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  • 401.
    Alfredsson, Hanna
    Högskolan i Kalmar, Naturvetenskapliga institutionen. Högskolan i Kalmar, Naturvetenskapliga institutionen.
    Prey selection of European eel (Anguilla anguilla) larvae in the Sargasso Sea: a molecular approach.2009Independent thesis Advanced level (degree of Master (Two Years)), 40 poäng / 60 hpOppgave
    Abstract [en]

    Abstract

    The European eel (Anguilla anguilla) migrates to the Sargasso Sea to spawn. Even though the biology of A. anguilla leptocephali in the Sargasso Sea has been studied for several decades, information regarding their diet has remained unknown until now. Previous dietary studies concerning other species of leptocephali in the Pacific Ocean have been limited to the recognition of identifiable prey remains amongst gut contents. Hence, in this study a molecular approach relying on the detection of prey DNA amongst gut contents was used to study dietary profiles of A. anguilla leptocephali in the Sargasso Sea.

     

    Leptocephali were collected during the circumglobal Galathea 3 expedition in spring 2007 to the Sargasso Sea. DNA extracted from gut contents were PCR amplified using universal primers targeting the nuclear 18S rRNA gene. In order to separate eel amplicons from prey amplicons, PCR products were analyzed by denaturing gradient gel electrophoresis (DGGE). Furthermore, clone libraries were constructed using universal primers targeting a portion of the 18S rRNA and mitochondrial COI gene, respectively. In total, the gut contents of 78 leptocephali were screened by DGGE.

     

    A diverse array of eukaryotic taxa was identified, hence demonstrating the applicability of a universal PCR- DGGE approach to study gut contents of leptocephali. The results presented here show, for the first time, that young stages of A. anguilla leptocephali feed on a large variety of zooplankton of which many were gelatinous (e.g. Hydrozoa, Thaliacea and Ctenophora). Several of the identified taxa also constitute important parts of the Sargasso Sea zooplankton community and are of size ranges (adult or larval stages) that made them reasonable as leptocephali prey.

    Fulltekst (pdf)
    FULLTEXT01
  • 402.
    Algotsson, Sarah
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för matematik (MA).
    Tror jag att jag kan det här?: En kvantitativ studie om elevers tilltro till sin egen matematiska förmåga i relation till faktisk prestation i metod-och problemlösningsuppgifter  2018Independent thesis Advanced level (professional degree), 10 poäng / 15 hpOppgave
    Abstract [sv]

    Denna kvantitativa forskningsrapport inriktar sig på hur elever uppfattar sin egen matematiska förmåga, vilken grad av tilltro eleverna har till sin förmåga och hur de presterar i matematikämnet med särskilt fokus på metod- och problemlösningsuppgifter. Den litteratur som ligger till grund för studien baseras på vad det innebär att tro på sin egen förmåga, förmågan att kunna värdera sig själv och sin förmåga samt matematikuppgifters betydelse för skapandet av självuppfattning och tilltro till den egna förmågan. Den forskningsmetod som används för att kunna besvara studiens frågeställningar är av kvantitativ karaktär och består av ett självskattningsformulär där syftet är att synliggöra elevernas grad av tilltro till den egna matematiska förmågan samt ett tillhörande matematiktest där eleverna löser metod- och problemlösningsuppgifter. Lösningsfrekvensen av de olika uppgiftstyperna analyseras i relation till elevernas grad av tilltro. Studien genomsyras av ett socialpsykologiskt perspektiv och resultatet teoretiseras genom att utgå från den socialpsykologiska teorin om själveffektivitet samt symbolisk interaktionism. För att analysera sambanden har materialet även analyserats ur ett statistiskt perspektiv genom analysverktyget SPSS. Resultatet av studien visar att det verkar finnas ett samband mellan elevernas grad av tilltro till sin matematiska förmåga och hur de presterar i både metod- och problemlösningsuppgifter.

    Fulltekst (pdf)
    fulltext
  • 403.
    Al-Hadad, Mohamed
    Linnéuniversitetet, Fakultetsnämnden för naturvetenskap och teknik, Institutionen för naturvetenskap, NV.
    Metodjämförelse mellan IMMAGE 800 och BN ProSpec för U-albumin, U-IgG, U-kappa och U-lambda2010Independent thesis Basic level (degree of Bachelor), 10 poäng / 15 hpOppgave
    Abstract [sv]

    Njurarna är ett organsystem med viktiga funktioner som exempelvis utsöndring av flertalet vattenlösliga substanser. För att sjukdomssymtom ska uppträda krävs mer än tre fjärdedelars bortfall av njurfunktionen, eftersom njurarna har en enorm reservkapacitet. Genom att analysera bland annat proteinerna albumin, immunoglobulin G, kappa och lambda i urin utreds om njurfunktionen fungerar som den ska. Analys av dessa proteiner kan ske med analysinstrumenten IMMAGE 800 från Beckman Coulter och BN ProSpec från DADE BEHRING. Båda dessa analysinstrument använder sig av metoden nefelometri, som är en metod där ljusspridning i en vätska eller gas kan mätas.

    Syftet med föreliggande studie var att analysera urinprover på både IMMAGE 800 och BN ProSpec och sedan jämföra resultaten. Under denna studie kalibrerades standardkurvor, genomfördes kvalitetskontroller och 37 prov analyserades. Samma prov analyserades flera gånger, både under samma dag och vid ett antal kommande dagar för att erhålla precisionen. Korrelationskoefficienten blev 0,999 för U-albumin; 0,998 för U-IgG; 0,947 för U-kappa och 0,883 för U-lambda. ProSpec kan således användas vid analys av U-albumin, U-IgG, U-kappa och U-lambda då den uppfyller EQUALIS kvalitetsmål.

    Fulltekst (pdf)
    FULLTEXT01
  • 404.
    Ali, Abdul Aziz
    et al.
    Linnéuniversitetet, Ekonomihögskolan (FEH), Institutionen för nationalekonomi och statistik (NS).
    Månsson, Kristofer
    Jönköping University, Sweden.
    Shukur, Ghazi
    Linnéuniversitetet, Ekonomihögskolan (FEH), Institutionen för nationalekonomi och statistik (NS).
    A wavelet-based variance ratio unit root test for a system of equations2019Inngår i: Studies in Nonlinear Dynamics and Econometrics, ISSN 1081-1826, E-ISSN 1558-3708, s. 1-16, artikkel-id 20180005Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In this paper, we suggest a unit root test for a system of equations using a spectral variance decomposition method based on the Maximal Overlap Discrete Wavelet Transform. We obtain the limiting distribution of the test statistic and study its small sample properties using Monte Carlo simulations. We find that, for multiple time series of small lengths, the wavelet-based method is robust to size distortions in the presence of cross-sectional dependence. The wavelet-based test is also more powerful than the Cross-sectionally Augmented Im et al. unit root test (Pesaran, M. H. 2007. "A Simple Panel Unit Root Test in the Presence of Cross-section Dependence." Journal of Applied Econometrics 22 (2): 265-312.) for time series with between 20 and 100 observations, using systems of 5 and 10 equations. We demonstrate the usefulness of the test through an application on evaluating the Purchasing Power Parity theory for the Group of 7 countries and find support for the theory, whereas the test by Pesaran (Pesaran, M. H. 2007. "A Simple Panel Unit Root Test in the Presence of Cross-section Dependence." Journal of Applied Econometrics 22 (2): 265-312.) finds no such support. © 2019 Walter de Gruyter GmbH, Berlin/Boston.

  • 405.
    Ali, Amjad
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för datavetenskap (DV).
    Migration from Internet Protocol Version 4 To Internet Protocol Version 62014Independent thesis Advanced level (degree of Master (One Year)), 10 poäng / 15 hpOppgave
    Abstract [en]

    IPv4 has played it big role in spreading Internet and Internet based applications for more than 20 years. Now it will hand over the stage to its more powerful successor IPv6. IP is an important component of the TCP/IP protocol suit and the Internet is built on it.

             IPv6 is a new generation protocol suite which has been proposed by the Internet Engineering Task Force (IETF) which uses the 128-bit address instead of IPv4 32-bit address. Moving to the next generation of Internet Protocol became an issue to solve many problems in the current generation.

             Unfortunately IPv4 and IPv6 are incompatible with each other. It is necessary to create smooth transition mechanisms that a transition mechanism is required during the time of migration from IPv4 to IPv6 networks. This paper aims to supplement this by presenting the design and implementation of IPv4 to IPv6 Transition Scenarios. This paper very clearly illustrates the transition of IPv4-to-IPv6 Transition mechanisms along with how to execute IPv6 commands.

    Fulltekst (pdf)
    fulltext
  • 406.
    Ali, Sharafat
    et al.
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för byggd miljö och energiteknik (BET).
    Jonson, Bo
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för byggd miljö och energiteknik (BET).
    Difficulties associated with the formation of oxynitride glasses2014Konferansepaper (Fagfellevurdert)
  • 407.
    Ali, Sharafat
    et al.
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för bygg- och energiteknik (BE).
    Jonson, Bo
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för bygg- och energiteknik (BE).
    Formation and properties of nitrogen rich Ca-Si- (Al)-O-N glasses and Ceramics2014Inngår i: Conference proceeding 2014 Spring World Congress on Engineering and Technology, Shanghai, China (April 2014)., 2014, s. 59-59Konferansepaper (Fagfellevurdert)
  • 408.
    Ali, Sharafat
    et al.
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för byggd miljö och energiteknik (BET).
    Jonson, Bo
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för byggd miljö och energiteknik (BET).
    Properties of nitrogen rich mixed La-Pr silicon oxynitride glasses2014Konferansepaper (Fagfellevurdert)
  • 409.
    Ali, Sharafat
    et al.
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för byggd miljö och energiteknik (BET).
    Jonson, Bo
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för byggd miljö och energiteknik (BET).
    J. Pomeroy, Michael
    University of Limerick, Ireland.
    Stuart, Hampshire
    University of Limerick, Ireland.
    Issues associated with the development of transparent oxynitride glasses2015Inngår i: Ceramics International, ISSN 0272-8842, E-ISSN 1873-3956, Vol. 41, nr 3, s. 3345-3354Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Oxynitride glasses and glass ceramics are increasingly recognized as potential materials in specialist applications in modern industrial sectors. Oxynitride glasses have superior mechanical, rheological and optical properties to their oxide glass counterparts. Properties of these glasses can be tailored by changes in nitrogen content and additions of various alkaline-earth and or rare-earth elements. In contrast to oxide glasses, oxynitride glasses are difficult to prepare which adds to production costs. Furthermore, they contain impurities in the form of elemental silicon and silicides, have poor oxidation resistance in air above their glass transition temperatures and have poor transparency in the visible region. This article reviews the above issues in relation to the potential applications of these glasses.

  • 410.
    Ali, Sharafat
    et al.
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för byggd miljö och energiteknik (BET).
    Paul, Biplab
    Linköping University.
    Magnusson, Roger
    Linköping University.
    Greczynski, Grzegorz
    Linköping University.
    Broitman, Esteban
    Linköping University.
    Jonson, Bo
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för byggd miljö och energiteknik (BET).
    Eklund, Per
    Linköping University.
    Birch, Jens
    Linköping University.
    Novel transparent Mg-Si-O-N thin films with high hardness and refractive index2016Inngår i: Vacuum, ISSN 0042-207X, E-ISSN 1879-2715, Vol. 131, s. 1-4Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    There is an increasing demand for glass materials with better mechanical and optical properties for display and electronic applications. This paper describes the deposition of novel thin films of Mg-Si-O-N onto float glass substrates. Amorphous thin films in the Mg-Si-O-N system with high nitrogen and magnesium contents were deposited by reactive RF magnetron co-sputtering from Mg and Si targets in Ar/N2/O2 gas mixtures. The thin films studied span an unprecedented range of compositions up to 45 at% Mg and 80 at% N out of cations and anions respectively. Thin films in the Mg-Si-O-N system were found to be homogeneous and transparent in the visible region. Mechanical properties like hardness (H) and reduced elastic modulus (Er) show high values, up to 21 GPa and 166 GPa respectively. The refractive index (1.87-2.00) increases with increasing magnesium and nitrogen contents.

  • 411.
    Alice, Reinaudo
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för matematik (MA).
    Empirical testing of pseudo random number generators based on elliptic curves2015Independent thesis Basic level (degree of Bachelor), 10 poäng / 15 hpOppgave
    Abstract [en]

    An introduction on random numbers, their history and applications is given, along with explanations of different methods currently used to generate them. Such generators can be of different kinds, and in particular they can be based on physical systems or algorithmic procedures. The latter type of procedures gives rise to pseudo-random number generators. Specifically, several such generators which are based on elliptic curves are examined. Therefore, in order to ease understanding, a basic primer on elliptic curves over fields and the operations arising from their group structure is also provided. Empirical tests to verify randomness of generated sequences are then considered. Afterwards, there are some statistical considerations and observations about theoretical properties of the generators at hand, useful in order to use them optimally. Finally, several randomly generated curves are created and used to produce pseudo-random sequences which are then tested by means of the previously described generators. In the end, an analysis of the results is attempted and some final considerations are made.

    Fulltekst (pdf)
    fulltext
  • 412.
    Alimohammad, Roohollah
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för informatik (IK).
    The Foundations and Limitations of Public Information on Sustainability and Food Purchasing in Sweden2015Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    This thesis examines the nature and effects of current public information about food production, purchasing and sustainability that is available in Sweden. The thesis follows a two part structure based on the Action Research Cycle; it focuses predominantly on the initial diagnostic stage, using document review, questionnaires and Cultural Probes to examine what information is currently available to Swedish consumers, as well as how they respond to this information. The thesis then moves towards the action planning stage of the Action Research Cycle, using current academic literature in IS with the findings of my diagnostic research to suggest ways in which information-communication technology can be used to improve upon the current situation, and paving the way for future research in the area of public information and food sustainability.

    Fulltekst (pdf)
    Roohollah Alimohammad - Master Thesis
  • 413.
    Alissandrakis, Aris
    et al.
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för medieteknik (ME).
    Milrad, Marcelo
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för medieteknik (ME).
    Designing interactive mobile services to promote civic participation in northern Uganda2013Inngår i: ICT for Anti-Corruption, Democracy And Education In East Africa / [ed] Katja Sarajeva, Stockholm: Stockholm University, 2013, s. 53-65Kapittel i bok, del av antologi (Fagfellevurdert)
    Abstract [en]

    This chapter presents the activities and outcomes of the "People's Voices: Developing Cross Media Services to Promote Citizens Participation in Local Governance Activities" project.

    The aims of the project were a) to identify and describe a number of cross media services that can be used to promote citizens’ participation in political decisions and civic activities, and b) to develop a conceptual design and a prototype system of such a service. The project included a number of field trips from Sweden to Uganda, and used participatory design and ethnographic techniques for requirements elicitation, actively involving the different stakeholders. The developed system allows people in Uganda to use their mobile phones to submit reports of irregularities in local governance or poor services delivery using an interactive voice menu interface.

    We hope that our specific contribution will emphasize on how novel ways of integrating and using ICT can provide opportunities to encourage and facilitate civic engagement in North Uganda. The potential massive adoption of the kind of interactive mobile services described in this book chapter can be used in unique ways to provide opportunities to make governmental services more innovative, transparent and cost-effective, as well as to encourage citizens to become more engaged and goal-focused for the common good of their society.

    Fulltekst (pdf)
    fulltext
  • 414.
    Alissandrakis, Aris
    et al.
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för datavetenskap och medieteknik (DM), Institutionen för medieteknik (ME).
    Nake, Isabella
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för datavetenskap och medieteknik (DM), Institutionen för medieteknik (ME).
    A New Approach for Visualizing Quantified Self Data Using Avatars2016Inngår i: Proceedings of the 2016 ACM International Joint Conference on Pervasive and Ubiquitous Computing: Adjunct, New York, NY, USA: ACM Press, 2016, s. 522-527Konferansepaper (Fagfellevurdert)
    Abstract [en]

    In recent years, it is becoming more common for people to use applications or devices that keep track of their life and activities, such as physical fitness, places they visited, the music they listen to, or pictures they took. This generates data that are used by the service providers for a variety of (usually analytics) purposes, but commonly there are limitations on how the users themselves can also explore or interact with these data. Our position paper describes a new approach of visualizing such Quantified Self data, in a meaningful and enjoyable way that can give the users personal insights into their own data. The visualization of the information is proposed as an avatar that maps the different activities the user is engaged with, along with each such activity level, as graphical features. An initial prototype (both in terms of graphical design and software architecture) as well as possible future extensions are discussed.

  • 415.
    Alissandrakis, Aris
    et al.
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för datavetenskap och medieteknik (DM), Institutionen för medieteknik (ME).
    Reski, Nico
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för datavetenskap och medieteknik (DM), Institutionen för medieteknik (ME).
    Using Mobile Augmented Reality to Facilitate Public Engagement2017Inngår i: Extended Papers of the International Symposium on Digital Humanities (DH 2016) / [ed] Koraljka Golub, Marcelo Milrad, CEUR-WS , 2017, Vol. 2021, s. 99-109Konferansepaper (Fagfellevurdert)
    Abstract [en]

    This paper presents our initial efforts towards the development of a framework for facilitating public engagement through the use of mobile Augmented Reality (mAR), that fall under the overall project title "Augmented Reality for Public Engagement" (PEAR). We present the concept, implementation, and discuss the results from the deployment of a mobile phone app (PEAR 4 VXO). The mobile app was used for a user study in conjunction with a campaign carried out by Växjö municipality (Sweden) while exploring how to get citizens more engaged in urban planning actions and decisions. These particular activities took place during spring 2016.One of the salient features of our approach is that it combines novel ways of using mAR together with social media, online databases, and sensors, to support public engagement. In addition, the data collection process and audience engagement were tested in a follow-up limited deployment.The analysis and outcomes of our initial results validate the overall concept and indicate the potential usefulness of the app as a tool, but also highlight the need for an active campaign from the part of the stakeholders.Our future efforts will focus on addressing some of the problems and challenges that we have identified during the different phases of this user study.

    Fulltekst (pdf)
    Alissandrakis_Reski_PEAR_2017.pdf
  • 416.
    Alissandrakis, Aris
    et al.
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för datavetenskap och medieteknik (DM).
    Reski, Nico
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för datavetenskap och medieteknik (DM).
    Laitinen, Mikko
    University of Eastern Finland, Finland.
    Tyrkkö, Jukka
    Linnéuniversitetet, Fakulteten för konst och humaniora (FKH), Institutionen för språk (SPR).
    Levin, Magnus
    Linnéuniversitetet, Fakulteten för konst och humaniora (FKH), Institutionen för språk (SPR).
    Lundberg, Jonas
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för datavetenskap och medieteknik (DM).
    Visualizing dynamic text corpora using Virtual Reality2018Inngår i: ICAME 39 : Tampere, 30 May – 3 June, 2018: Corpus Linguistics and Changing Society : Book of Abstracts, Tampere: University of Tampere , 2018, s. 205-205Konferansepaper (Fagfellevurdert)
    Abstract [en]

    In recent years, data visualization has become a major area in Digital Humanities research, and the same holds true also in linguistics. The rapidly increasing size of corpora, the emergence of dynamic real-time streams, and the availability of complex and enriched metadata have made it increasingly important to facilitate new and innovative approaches to presenting and exploring primary data. This demonstration showcases the uses of Virtual Reality (VR) in the visualization of geospatial linguistic data using data from the Nordic Tweet Stream (NTS) project (see Laitinen et al 2017). The NTS data for this demonstration comprises a full year of geotagged tweets (12,443,696 tweets from 273,648 user accounts) posted within the Nordic region (Denmark, Finland, Iceland, Norway, and Sweden). The dataset includes over 50 metadata parameters in addition to the tweets themselves.

    We demonstrate the potential of using VR to efficiently find meaningful patterns in vast streams of data. The VR environment allows an easy overview of any of the features (textual or metadata) in a text corpus. Our focus will be on the language identification data, which provides a previously unexplored perspective into the use of English and other non-indigenous languages in the Nordic countries alongside the native languages of the region.

    Our VR prototype utilizes the HTC Vive headset for a room-scale VR scenario, and it is being developed using the Unity3D game development engine. Each node in the VR space is displayed as a stacked cuboid, the equivalent of a bar chart in a three-dimensional space, summarizing all tweets at one geographic location for a given point in time (see: https://tinyurl.com/nts-vr). Each stacked cuboid represents information of the three most frequently used languages, appropriately color coded, enabling the user to get an overview of the language distribution at each location. The VR prototype further encourages users to move between different locations and inspect points of interest in more detail (overall location-related information, a detailed list of all languages detected, the most frequently used hashtags). An underlying map outlines country borders and facilitates orientation. In addition to spatial movement through the Nordic areas, the VR system provides an interface to explore the Twitter data based on time (days, weeks, months, or time of predefined special events), which enables users to explore data over time (see: https://tinyurl.com/nts-vr-time).

    In addition to demonstrating how the VR methods aid data visualization and exploration, we will also briefly discuss the pedagogical implications of using VR to showcase linguistic diversity.

  • 417.
    Alissandrakis, Aris
    et al.
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för datavetenskap och medieteknik (DM).
    Reski, Nico
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för datavetenskap och medieteknik (DM).
    Laitinen, Mikko
    University of Eastern Finland, Finland.
    Tyrkkö, Jukka
    Linnéuniversitetet, Fakulteten för konst och humaniora (FKH), Institutionen för språk (SPR).
    Lundberg, Jonas
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för datavetenskap och medieteknik (DM).
    Levin, Magnus
    Linnéuniversitetet, Fakulteten för konst och humaniora (FKH), Institutionen för språk (SPR).
    Visualizing rich corpus data using virtual reality2019Inngår i: Studies in Variation, Contacts and Change in English, ISSN 1797-4453, E-ISSN 1797-4453, Vol. 20Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We demonstrate an approach that utilizes immersive virtual reality (VR) to explore and interact with corpus linguistics data. Our case study focuses on the language identification parameter in the Nordic Tweet Stream corpus, a dynamic corpus of Twitter data where each tweet originated within the Nordic countries. We demonstrate how VR can provide previously unexplored perspectives into the use of English and other non-indigenous languages in the Nordic countries alongside the native languages of the region and showcase its geospatial variation. We utilize a head-mounted display (HMD) for a room-scale VR scenario that allows 3D interaction by using hand gestures. In addition to spatial movement through the Nordic areas, the interface enables exploration of the Twitter data based on time (days, weeks, months, or time of predefined special events), making it particularly useful for diachronic investigations.

    In addition to demonstrating how the VR methods aid data visualization and exploration, we briefly discuss the pedagogical implications of using VR to showcase linguistic diversity. Our empirical results detail students’ reactions to working in this environment. The discussion part examines the benefits, prospects and limitations of using VR in visualizing corpus data.

  • 418.
    Aliti, Admirim
    et al.
    Linnéuniversitetet, Fakultetsnämnden för naturvetenskap och teknik, Institutionen för datavetenskap, fysik och matematik, DFM.
    Akkaya, Deniz
    Linnéuniversitetet, Fakultetsnämnden för naturvetenskap och teknik, Institutionen för datavetenskap, fysik och matematik, DFM.
    Employees' Role in Improving Information Systems Security2011Independent thesis Advanced level (degree of Master (One Year)), 10 poäng / 15 hpOppgave
    Abstract [en]

    Information security is one of the most essential concerns in today’s organizations. IT departments in larger organizations are tasked to implement security, by both ensuring to have pertinent hardware and software, and likewise enlighten, teach and educate organization’s employees about security issues. The aim of this research is to focus on the human factor of the organization, which impacts the security of the information, since technological solutions of technical problems become incomprehensible without human recognition about security. If the security is not addressed in firms, this might lead to essential data of the organization to be compromised. This study explores ways to enhance information security and improve the human factor by integrating the crucial information security elements in organizations. Social constructivist worldview is adopted throughout the study, and an inductive based - qualitative approach, a single case study design and hermeneutical analysis for analyzing the observations and interviews are utilized. The research setting for this study is Växjö Municipality in Sweden. The empirical investigation suggests that human factor plays an essential role in maintaining information security, and organizations can improve employees’ role by keeping their security policies up to date and find the best ways to disseminate that information. As a result, this research comes up with “information security human management model” for organizations.

    Fulltekst (pdf)
    Master_Thesis_Informatics_Admirim Aliti_Deniz Akkaya
  • 419.
    Aliu, Armend
    Växjö universitet, Fakulteten för matematik/naturvetenskap/teknik, Matematiska och systemtekniska institutionen.
    Matematiksvårigheter: textuppgifter inom algebra2006Independent thesis Basic level (degree of Bachelor), 10 poäng / 15 hpOppgave
    Abstract [sv]

    I detta arbete fördjupar jag mina kunskaper omkring elevernas svårigheter, kring dem matematiska begrepp och kring formuleringen av de olika textuppgifter som framkommer inom avsnittet algebra. Här ville jag ta reda på om det är matematiska begreppen eller om det är formuleringarna i matematikuppgifterna som eleverna har svårt att förstå samtidigt som jag ville se vilka strategier som eleverna använder sig av när de får olika typer av uppgifter inom avsnittet algebra. De klasser som jag ska göra min undersökning på är två åk 1 klasser som går handelsprogrammet. Detta medför att de läser matematik –A kursen och håller på med avsnittet som handlar om algebra och ekvationer. Jag utför en stor undersökning i form av prov som består av 8 uppgifter. Efter att provet genomförs och rättas så väljs några elever för en intervju. Förhoppningen var att med hjälp av intervjun komma underfund med vad i dessa uppgifter eleverna har problem med. Arbetet visar att elever oftast är osäkra när det gäller de olika matematiska begreppen. När det gäller formuleringen i textuppgifter har många elever i min undersökning svårt att hålla isär och hämta in rätt information för att kunna lösa uppgifterna rätt. Vidare visar arbetet att majoriteten av eleverna har problem med formuleringarna i uppgiften dvs. när uppgiften är lång och mycket information ges.

    Fulltekst (pdf)
    FULLTEXT01
  • 420. Aliu, E.
    et al.
    Archambault, S.
    Arlen, T.
    Aune, T.
    Behera, B.
    Beilicke, M.
    Benbow, W.
    Berger, K.
    Bird, R.
    Bouvier, A.
    Buckley, J. H.
    Bugaev, V.
    Byrum, K.
    Cerruti, M.
    Chen, X.
    Ciupik, L.
    Connolly, M. P.
    Cui, W.
    Duke, C.
    Dumm, J.
    Errando, M.
    Falcone, A.
    Federici, S.
    Feng, Q.
    Finley, J. P.
    Fleischhack, H.
    Fortin, P.
    Fortson, L.
    Furniss, A.
    Galante, N.
    Gillanders, G. H.
    Griffin, S.
    Griffiths, S. T.
    Grube, J.
    Gyuk, G.
    Hanna, D.
    Holder, J.
    Hughes, G.
    Humensky, T. B.
    Johnson, C. A.
    Kaaret, P.
    Kertzman, M.
    Khassen, Y.
    Kieda, D.
    Krawczynski, H.
    Krennrich, F.
    Lang, M. J.
    Madhavan, A. S.
    Maier, G.
    Majumdar, P.
    McArthur, S.
    McCann, A.
    Meagher, K.
    Millis, J.
    Moriarty, P.
    Mukherjee, R.
    Nieto, D.
    O’Faoláin de Bhróithe, A.
    Ong, R. A.
    Otte, A. N.
    Park, N.
    Perkins, J. S.
    Pohl, M.
    Popkow, A.
    Prokoph, Heike
    DESY, Germany .
    Quinn, J.
    Ragan, K.
    Reyes, L. C.
    Reynolds, P. T.
    Richards, G. T.
    Roache, E.
    Sembroski, G. H.
    Smith, A. W.
    Staszak, D.
    Telezhinsky, I.
    Theiling, M.
    Varlotta, A.
    Vassiliev, V. V.
    Vincent, S.
    Wakely, S. P.
    Weekes, T. C.
    Weinstein, A.
    Welsing, R.
    Williams, D. A.
    Zajczyk, A.
    Zitzer, B.
    A Three-year Multi-wavelength Study of the Very-high-energy γ-Ray Blazar 1ES 0229+2002014Inngår i: Astrophysical Journal, ISSN 0004-637X, E-ISSN 1538-4357, Vol. 782, nr 1, artikkel-id 13Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The high-frequency-peaked BL Lacertae object 1ES 0229+200 is a relatively distant (z = 0.1396), hard-spectrum (Γ ~ 2.5), very-high-energy (VHE; E > 100 GeV) emitting γ-ray blazar. VHE measurements of this active galactic nucleus have been used to place constraints on the intensity of the extragalactic background light and the intergalactic magnetic field (IGMF). A multi-wavelength study of this object centered around VHE observations by Very Energetic Radiation Imaging Telescope Array System (VERITAS) is presented. This study obtained, over a period of three years, an 11.7 standard deviation detection and an average integral flux F(E > 300 GeV) = (23.3 ± 2.8stat ± 5.8sys× 10–9 photons m–2 s–1, or 1.7% of the Crab Nebula's flux (assuming the Crab Nebula spectrum measured by H.E.S.S). Supporting observations from Swift and RXTE are analyzed. TheSwift observations are combined with previously published Fermi observations and the VHE measurements to produce an overall spectral energy distribution which is then modeled assuming one-zone synchrotron-self-Compton emission. The χ2probability of the TeV flux being constant is 1.6%. This, when considered in combination with measured variability in the X-ray band, and the demonstrated variability of many TeV blazars, suggests that the use of blazars such as 1ES 0229+200 for IGMF studies may not be straightforward and challenges models that attribute hard TeV spectra to secondary γ-ray production along the line of sight.

  • 421. Aliu, E.
    et al.
    Archambault, S.
    Arlen, T.
    Aune, T.
    Beilicke, M.
    Benbow, W.
    Bird, R.
    Bouvier, A.
    Bradbury, S. M.
    Buckley, J. H.
    Bugaev, V.
    Byrum, K.
    Cannon, A.
    Cesarini, A.
    Ciupik, L.
    Collins-Hughes, E.
    Connolly, M. P.
    Cui, W.
    Dickherber, R.
    Duke, C.
    Dumm, J.
    Dwarkadas, V. V.
    Errando, M.
    Falcone, A.
    Federici, S.
    Feng, Q.
    Finley, J. P.
    Finnegan, G.
    Fortson, L.
    Furniss, A.
    Galante, N.
    Gall, D.
    Gillanders, G. H.
    Godambe, S.
    Gotthelf, E. V.
    Griffin, S.
    Grube, J.
    Gyuk, G.
    Hanna, D.
    Holder, J.
    Huan, H.
    Hughes, G.
    Humensky, T. B.
    Kaaret, P.
    Karlsson, N.
    Kertzman, M.
    Khassen, Y.
    Kieda, D.
    Krawczynski, H.
    Krennrich, F.
    Lang, M. J.
    Lee, K.
    Madhavan, A. S.
    Maier, G.
    Majumdar, P.
    McArthur, S.
    McCann, A.
    Millis, J.
    Moriarty, P.
    Mukherjee, R.
    Nelson, T.
    O’Faoláin de Bhróithe, A.
    Ong, R. A.
    Orr, M.
    Otte, A. N.
    Pandel, D.
    Park, N.
    Perkins, J. S.
    Pohl, M.
    Popkow, A.
    Prokoph, Heike
    DESY, Germany .
    Quinn, J.
    Ragan, K.
    Reyes, L. C.
    Reynolds, P. T.
    Roache, E.
    Rose, H. J.
    Ruppel, J.
    Saxon, D. B.
    Schroedter, M.
    Sembroski, G. H.
    \c Sentürk, G. D.
    Skole, C.
    Telezhinsky, I.
    Tesić, G.
    Theiling, M.
    Thibadeau, S.
    Tsurusaki, K.
    Tyler, J.
    Varlotta, A.
    Vassiliev, V. V.
    Vincent, S.
    Wakely, S. P.
    Ward, J. E.
    Weekes, T. C.
    Weinstein, A.
    Weisgarber, T.
    Welsing, R.
    Williams, D. A.
    Zitzer, B.
    Discovery of TeV Gamma-Ray Emission toward Supernova Remnant SNR G78.2+2.12013Inngår i: Astrophysical Journal, ISSN 0004-637X, E-ISSN 1538-4357, \apj, Vol. 770, nr 2, artikkel-id 93Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We report the discovery of an unidentified, extended source of very-high-energy gamma-ray emission, VER J2019+407, within the radio shell of the supernova remnant SNR G78.2+2.1, using 21.4 hr of data taken by the VERITAS gamma-ray observatory in 2009. These data confirm the preliminary indications of gamma-ray emission previously seen in a two-year (2007-2009) blind survey of the Cygnus region by VERITAS. VER J2019+407, which is detected at a post-trials significance of 7.5 standard deviations in the 2009 data, is localized to the northwestern rim of the remnant in a region of enhanced radio and X-ray emission. It has an intrinsic extent of  and its spectrum is well-characterized by a differential power law (dN/dE = N 0 × (E/TeV)–Γ) with a photon index of Γ = 2.37 ± 0.14stat ± 0.20sys and a flux normalization of N 0 = 1.5 ± 0.2stat ± 0.4sys × 10–12 photon TeV–1 cm–2 s–1. This yields an integral flux of 5.2 ± 0.8stat ± 1.4sys × 10–12 photon cm–2 s–1above 320 GeV, corresponding to 3.7% of the Crab Nebula flux. We consider the relationship of the TeV gamma-ray emission with the GeV gamma-ray emission seen from SNR G78.2+2.1 as well as that seen from a nearby cocoon of freshly accelerated cosmic rays. Multiple scenarios are considered as possible origins for the TeV gamma-ray emission, including hadronic particle acceleration at the SNR shock.

  • 422. Aliu, E.
    et al.
    Archambault, S.
    Arlen, T.
    Aune, T.
    Beilicke, M.
    Benbow, W.
    Bird, R.
    Bouvier, A.
    Buckley, J. H.
    Bugaev, V.
    Cesarini, A.
    Ciupik, L.
    Connolly, M. P.
    Cui, W.
    Dumm, J.
    Errando, M.
    Falcone, A.
    Federici, S.
    Feng, Q.
    Finley, J. P.
    Fortin, P.
    Fortson, L.
    Furniss, A.
    Galante, N.
    Gérard, L.
    Gillanders, G. H.
    Griffin, S.
    Grube, J.
    Gyuk, G.
    Hanna, D.
    Holder, J.
    Hughes, G.
    Humensky, T. B.
    Kaaret, P.
    Kertzman, M.
    Khassen, Y.
    Kieda, D.
    Krawczynski, H.
    Krennrich, F.
    Lang, M. J.
    Madhavan, A. S.
    Maier, G.
    Majumdar, P.
    McArthur, S.
    McCann, A.
    Moriarty, P.
    Mukherjee, R.
    Nieto, D.
    O’Faoláin de Bhróithe, A.
    Ong, R. A.
    Orr, M.
    Otte, A. N.
    Park, N.
    Perkins, J. S.
    Pohl, M.
    Popkow, A.
    Prokoph, Heike
    DESY, Germany.
    Quinn, J.
    Ragan, K.
    Reyes, L. C.
    Reynolds, P. T.
    Richards, G. T.
    Roache, E.
    Saxon, D. B.
    Sembroski, G. H.
    Skole, C.
    Smith, A. W.
    Soares-Furtado, M.
    Staszak, D.
    Telezhinsky, I.
    Te\v sić, G.
    Theiling, M.
    Varlotta, A.
    Vassiliev, V. V.
    Vincent, S.
    Wakely, S. P.
    Weekes, T. C.
    Weinstein, A.
    Welsing, R.
    Williams, D. A.
    Zitzer, B.
    Collaboration, V E R I T A S
    Böttcher, M.
    Fumagalli, M.
    Jadhav, J.
    Long Term Observations of B2 1215+30 with VERITAS2013Inngår i: Astrophysical Journal, ISSN 0004-637X, E-ISSN 1538-4357, Vol. 779, nr 2, artikkel-id 92Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We report on VERITAS observations of the BL Lac object B2 1215+30 between 2008 and 2012. During this period, the source was detected at very high energies (VHEs; E > 100 GeV) by VERITAS with a significance of 8.9s and showed clear variability on timescales larger than months. In 2011, the source was found to be in a relatively bright state and a power-law fit to the differential photon spectrum yields a spectral index of 3.6 +/- 0.4(stat) +/- 0.3(syst) withan integral flux above 200 GeV of (8.0 +/- 0.9(stat) +/- 3.2(syst)) x 10(-12) cm(-2) s(-1). No short term variability could be detected during the bright state in 2011. Multi-wavelength data were obtained contemporaneously with the VERITAS observations in 2011 and cover optical (Super-LOTIS, MDM, Swift/UVOT), X-ray (Swift/XRT), and gamma-ray (Fermi-LAT) frequencies. These were used to construct the spectral energy distribution (SED) of B2 1215+30. A one-zone leptonic model is used to model the blazar emission and the results are compared to those of MAGIC from early 2011 and other VERITAS-detected blazars. The SED can be reproduced well with model parameters typical for VHE-detected BL Lac objects.

  • 423. Aliu, E.
    et al.
    Archambault, S.
    Arlen, T.
    Aune, T.
    Beilicke, M.
    Benbow, W.
    Bird, R.
    Böttcher, M.
    Bouvier, A.
    Bugaev, V.
    Byrum, K.
    Cesarini, A.
    Ciupik, L.
    Collins-Hughes, E.
    Connolly, M. P.
    Cui, W.
    Dickherber, R.
    Duke, C.
    Dumm, J.
    Errando, M.
    Falcone, A.
    Federici, S.
    Feng, Q.
    Finley, J. P.
    Finnegan, G.
    Fortson, L.
    Furniss, A.
    Galante, N.
    Gall, D.
    Gillanders, G. H.
    Griffin, S.
    Grube, J.
    Gyuk, G.
    Hanna, D.
    Holder, J.
    Hughes, G.
    Humensky, T. B.
    Kaaret, P.
    Kertzman, M.
    Khassen, Y.
    Kieda, D.
    Krawczynski, H.
    Krennrich, F.
    Lang, M. J.
    Madhavan, A. S.
    Maier, G.
    Majumdar, P.
    McArthur, S.
    McCann, A.
    Moriarty, P.
    Mukherjee, R.
    Nelson, T.
    O’Faoláin de Bhróithe, A.
    Ong, R. A.
    Orr, M.
    Otte, A. N.
    Park, N.
    Perkins, J. S.
    Pichel, A.
    Pohl, M.
    Popkow, A.
    Prokoph, Heike
    DESY, Germany.
    Quinn, J.
    Ragan, K.
    Reyes, L. C.
    Reynolds, P. T.
    Roache, E.
    Saxon, D. B.
    Schroedter, M.
    Sembroski, G. H.
    Skole, C.
    Smith, A. W.
    Staszak, D.
    Telezhinsky, I.
    Theiling, M.
    Tyler, J.
    Varlotta, A.
    Vassiliev, V. V.
    Wakely, S. P.
    Weekes, T. C.
    Weinstein, A.
    Welsing, R.
    Williams, D. A.
    Zitzer, B.
    Multiwavelength Observations and Modeling of 1ES 1959+650 in a Low Flux State2013Inngår i: Astrophysical Journal, ISSN 0004-637X, E-ISSN 1538-4357, Vol. 775, nr 1, artikkel-id 3Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We report on the VERITAS observations of the high-frequency peaked BL Lac object 1ES 1959+650 in the period 2007-2011. This source is detected at TeV energies by VERITAS at 16.4 standard deviation (σ) significance in 7.6 hr of observation in a low flux state. A multiwavelength spectral energy distribution (SED) is constructed from contemporaneous data from VERITAS,Fermi-LAT, RXTE PCA, and Swift UVOT. Swift XRT data is not included in the SED due to a lack of simultaneous observations with VERITAS. In contrast to the orphan γ-ray flare exhibited by this source in 2002, the X-ray flux of the source is found to vary by an order of magnitude, while other energy regimes exhibit less variable emission. A quasi-equilibrium synchrotron self-Compton model with an additional external radiation field is used to describe three SEDs corresponding to the lowest, highest, and average X-ray states. The variation in the X-ray spectrum is modeled by changing the electron injection spectral index, with minor adjustments of the kinetic luminosity in electrons. This scenario produces small-scale flux variability of the order of  2 in the high energy (E > 1 MeV) and very high energy (E > 100 GeV) γ-ray regimes, which is corroborated by the Fermi-LAT, VERITAS, and Whipple 10 m telescope light curves.

  • 424. Aliu, E.
    et al.
    Archambault, S.
    Arlen, T.
    Aune, T.
    Beilicke, M.
    Benbow, W.
    Bouvier, A.
    Bradbury, S. M.
    Buckley, J. H.
    Bugaev, V.
    Byrum, K.
    Cannon, A.
    Cesarini, A.
    Christiansen, J. L.
    Ciupik, L.
    Collins-Hughes, E.
    Connolly, M. P.
    Cui, W.
    Decerprit, G.
    Dickherber, R.
    Dumm, J.
    Errando, M.
    Falcone, A.
    Feng, Q.
    Ferrer, F.
    Finley, J. P.
    Finnegan, G.
    Fortson, L.
    Furniss, A.
    Galante, N.
    Gall, D.
    Godambe, S.
    Griffin, S.
    Grube, J.
    Gyuk, G.
    Hanna, D.
    Holder, J.
    Huan, H.
    Hughes, G.
    Humensky, T. B.
    Kaaret, P.
    Karlsson, N.
    Kertzman, M.
    Khassen, Y.
    Kieda, D.
    Krawczynski, H.
    Krennrich, F.
    Lee, K.
    Madhavan, A. S.
    Maier, G.
    Majumdar, P.
    McArthur, S.
    McCann, A.
    Moriarty, P.
    Mukherjee, R.
    Ong, R. A.
    Orr, M.
    Otte, A. N.
    Park, N.
    Perkins, J. S.
    Pohl, M.
    Prokoph, Heike
    DESY, Germany.
    Quinn, J.
    Ragan, K.
    Reyes, L. C.
    Reynolds, P. T.
    Roache, E.
    Rose, H. J.
    Ruppel, J.
    Saxon, D. B.
    Schroedter, M.
    Sembroski, G. H.
    \c Sentürk, G. D.
    Skole, C.
    Smith, A. W.
    Staszak, D.
    Telezhinsky, I.
    Te\v sić, G.
    Theiling, M.
    Thibadeau, S.
    Tsurusaki, K.
    Varlotta, A.
    Vassiliev, V. V.
    Vincent, S.
    Vivier, M.
    Wagner, R. G.
    Wakely, S. P.
    Ward, J. E.
    Weekes, T. C.
    Weinstein, A.
    Weisgarber, T.
    Williams, D. A.
    Zitzer, B.
    VERITAS deep observations of the dwarf spheroidal galaxy Segue 12012Inngår i: Physical Review D, ISSN 1550-7998, E-ISSN 1550-2368, Vol. 85, nr 6, artikkel-id 062001Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The VERITAS array of Cherenkov telescopes has carried out a deep observational program on the nearby dwarf spheroidal galaxy Segue 1. We report on the results of nearly 48 hours of good quality selected data, taken between January 2010 and May 2011. No significant γ-ray emission is detected at the nominal position of Segue 1, and upper limits on the integrated flux are derived. According to recent studies, Segue 1 is the most dark matter-dominated dwarf spheroidal galaxy currently known. We derive stringent bounds on various annihilating and decaying dark matter particle models. The upper limits on the velocity-weighted annihilation cross-section are ⟨σv⟩95% CL≲10−23  cm3 s−1, improving our limits from previous observations of dwarf spheroidal galaxies by at least a factor of 2 for dark matter particle masses mχ≳300  GeV. The lower limits on the decay lifetime are at the level of τ95% CL≳1024  s. Finally, we address the interpretation of the cosmic ray lepton anomalies measured by ATIC and PAMELA in terms of dark matter annihilation, and show that the VERITAS observations of Segue 1 disfavor such a scenario.

  • 425. Aliu, E.
    et al.
    Archambault, S.
    Arlen, T.
    Aune, T.
    Beilicke, M.
    Benbow, W.
    Bouvier, A.
    Bradbury, S. M.
    Buckley, J. H.
    Bugaev, V.
    Byrum, K.
    Cannon, A.
    Cesarini, A.
    Ciupik, L.
    Collins-Hughes, E.
    Connolly, M. P.
    Cui, W.
    Decerprit, G.
    Dickherber, R.
    Duke, C.
    Dumm, J.
    Dwarkadas, V. V.
    Errando, M.
    Falcone, A.
    Feng, Q.
    Finley, J. P.
    Finnegan, G.
    Fortson, L.
    Furniss, A.
    Galante, N.
    Gall, D.
    Godambe, S.
    Griffin, S.
    Grube, J.
    Gyuk, G.
    Hanna, D.
    Holder, J.
    Huan, H.
    Hughes, G.
    Humensky, T. B.
    Kaaret, P.
    Karlsson, N.
    Kertzman, M.
    Khassen, Y.
    Kieda, D.
    Krawczynski, H.
    Krennrich, F.
    Lang, M. J.
    Lee, K.
    Maier, G.
    Majumdar, P.
    McArthur, S.
    McCann, A.
    Millis, J.
    Moriarty, P.
    Mukherjee, R.
    Nuñez, P. D.
    Ong, R. A.
    Orr, M.
    Otte, A. N.
    Pandel, D.
    Park, N.
    Perkins, J. S.
    Pohl, M.
    Prokoph, Heike
    DESY, Germany .
    Quinn, J.
    Ragan, K.
    Reyes, L. C.
    Reynolds, P. T.
    Roache, E.
    Rose, H. J.
    Ruppel, J.
    Saxon, D. B.
    Schroedter, M.
    Sembroski, G. H.
    Skole, C.
    Smith, A. W.
    Staszak, D.
    Telezhinsky, I.
    Tesić, G.
    Theiling, M.
    Thibadeau, S.
    Tsurusaki, K.
    Tyler, J.
    Varlotta, A.
    Vincent, S.
    Vivier, M.
    Wakely, S. P.
    Ward, J. E.
    Weekes, T. C.
    Weinstein, A.
    Weisgarber, T.
    Welsing, R.
    Williams, D. A.
    Zitzer, B.
    VERITAS Observations of the Nova in V407 Cygni2012Inngår i: Astrophysical Journal, ISSN 0004-637X, E-ISSN 1538-4357, \apj, Vol. 754, nr 1, artikkel-id 77Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We report on very high energy (E > 100 GeV) gamma-ray observations of V407 Cygni, a symbiotic binary that underwent a nova outburst producing 0.1-10 GeV gamma rays during 2010 March 10-26. Observations were made with the Very Energetic Radiation Imaging Telescope Array System during 2010 March 19-26 at relatively large zenith angles due to the position of V407 Cyg. An improved reconstruction technique for large zenith angle observations is presented and used to analyze the data. We do not detect V407 Cygni and place a differential upper limit on the flux at 1.6 TeV of 2.3 × 10–12 erg cm–2 s–1 (at the 95% confidence level). When considered jointly with data from Fermi-LAT, this result places limits on the acceleration of very high energy particles in the nova.

  • 426. Aliu, E.
    et al.
    Archambault, S.
    Arlen, T.
    Aune, T.
    Beilicke, M.
    Benbow, W.
    Bouvier, A.
    Buckley, J. H.
    Bugaev, V.
    Byrum, K.
    Cesarini, A.
    Ciupik, L.
    Collins-Hughes, E.
    Connolly, M. P.
    Cui, W.
    Dickherber, R.
    Duke, C.
    Dumm, J.
    Falcone, A.
    Federici, S.
    Feng, Q.
    Finley, J. P.
    Finnegan, G.
    Fortson, L.
    Furniss, A.
    Galante, N.
    Gall, D.
    Gillanders, G. H.
    Godambe, S.
    Griffin, S.
    Grube, J.
    Gyuk, G.
    Hanna, D.
    Holder, J.
    Huan, H.
    Hughes, G.
    Humensky, T. B.
    Kaaret, P.
    Karlsson, N.
    Khassen, Y.
    Kieda, D.
    Krawczynski, H.
    Krennrich, F.
    Lang, M. J.
    LeBohec, S.
    Lee, K.
    Lyutikov, M.
    Madhavan, A. S.
    Maier, G.
    Majumdar, P.
    McArthur, S.
    McCann, A.
    Moriarty, P.
    Mukherjee, R.
    Nelson, T.
    O’Faoláin de Bhróithe, A.
    Ong, R. A.
    Orr, M.
    Otte, A. N.
    Park, N.
    Perkins, J. S.
    Pohl, M.
    Prokoph, Heike
    DESY, Germany .
    Quinn, J.
    Ragan, K.
    Reyes, L. C.
    Reynolds, P. T.
    Roache, E.
    Saxon, D. B.
    Schroedter, M.
    Sembroski, G. H.
    Sentürk, G. D.
    Smith, A. W.
    Staszak, D.
    Telezhinsky, I.
    Te\v sić, G.
    Theiling, M.
    Thibadeau, S.
    Tsurusaki, K.
    Varlotta, A.
    Vincent, S.
    Vivier, M.
    Wagner, R. G.
    Wakely, S. P.
    Weekes, T. C.
    Weinstein, A.
    Welsing, R.
    Williams, D. A.
    Zitzer, B.
    Kondratiev, V.
    Search for a Correlation between Very-high-energy Gamma Rays and Giant Radio Pulses in the Crab Pulsar2012Inngår i: Astrophysical Journal, ISSN 0004-637X, E-ISSN 1538-4357, Vol. 760, nr 2, artikkel-id 136Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We present the results of a joint observational campaign between the Green Bank radio telescope and the VERITAS gamma-ray telescope, which searched for a correlation between the emission of very-high-energy (VHE) gamma rays (E γ > 150 GeV) and giant radio pulses (GRPs) from the Crab pulsar at 8.9 GHz. A total of 15,366 GRPs were recorded during 11.6 hr of simultaneous observations, which were made across four nights in 2008 December and in 2009 November and December. We searched for an enhancement of the pulsed gamma-ray emission within time windows placed around the arrival time of the GRP events. In total, eight different time windows with durations ranging from 0.033 ms to 72 s were positioned at three different locations relative to the GRP to search for enhanced gamma-ray emission which lagged, led, or was concurrent with, the GRP event. Furthermore, we performed separate searches on main pulse GRPs and interpulse GRPs and on the most energetic GRPs in our data sample. No significant enhancement of pulsed VHE emission was found in any of the preformed searches. We set upper limits of 5-10 times the average VHE flux of the Crab pulsar on the flux simultaneous with interpulse GRPs on single-rotation-period timescales. On ~8 s timescales around interpulse GRPs, we set an upper limit of 2-3 times the average VHE flux. Within the framework of recent models for pulsed VHE emission from the Crab pulsar, the expected VHE-GRP emission correlations are below the derived limits.

  • 427. Aliu, E.
    et al.
    Archambault, S.
    Arlen, T.
    Aune, T.
    Beilicke, M.
    Benbow, W.
    Bouvier, A.
    Buckley, J. H.
    Bugaev, V.
    Cesarini, A.
    Ciupik, L.
    Collins-Hughes, E.
    Connolly, M. P.
    Cui, W.
    Dickherber, R.
    Duke, C.
    Dumm, J.
    Dwarkadas, V. V.
    Errando, M.
    Falcone, A.
    Federici, S.
    Feng, Q.
    Finley, J. P.
    Finnegan, G.
    Fortson, L.
    Furniss, A.
    Galante, N.
    Gall, D.
    Gillanders, G. H.
    Godambe, S.
    Gotthelf, E. V.
    Griffin, S.
    Grube, J.
    Gyuk, G.
    Hanna, D.
    Holder, J.
    Hughes, G.
    Humensky, T. B.
    Kaaret, P.
    Kargaltsev, O.
    Karlsson, N.
    Khassen, Y.
    Kieda, D.
    Krawczynski, H.
    Krennrich, F.
    Lang, M. J.
    Lee, K.
    Madhavan, A. S.
    Maier, G.
    Majumdar, P.
    McArthur, S.
    McCann, A.
    Moriarty, P.
    Mukherjee, R.
    Nelson, T.
    O’Faoláin de Bhróithe, A.
    Ong, R. A.
    Orr, M.
    Otte, A. N.
    Park, N.
    Perkins, J. S.
    Pohl, M.
    Prokoph, Heike
    DESY, Germany.
    Quinn, J.
    Ragan, K.
    Reyes, L. C.
    Reynolds, P. T.
    Roache, E.
    Roberts, M.
    Saxon, D. B.
    Schroedter, M.
    Sembroski, G. H.
    Slane, P.
    Smith, A. W.
    Staszak, D.
    Telezhinsky, I.
    Tesić, G.
    Theiling, M.
    Thibadeau, S.
    Tsurusaki, K.
    Tyler, J.
    Varlotta, A.
    Vassiliev, V. V.
    Vincent, S.
    Vivier, M.
    Wakely, S. P.
    Weekes, T. C.
    Weinstein, A.
    Welsing, R.
    Williams, D. A.
    Zitzer, B.
    Discovery of TeV Gamma-Ray Emission from CTA 1 by VERITAS2013Inngår i: Astrophysical Journal, ISSN 0004-637X, E-ISSN 1538-4357, Vol. 764, nr 1, artikkel-id 38Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We report the discovery of TeV gamma-ray emission coincident with the shell-type radio supernova remnant (SNR) CTA 1 using the VERITAS gamma-ray observatory. The source, VER J0006+729, was detected as a 6.5 standard deviation excess over background and shows an extended morphology, approximated by a two-dimensional Gaussian of semimajor (semiminor) axis 030 (024) and a centroid 5' from the Fermi gamma-ray pulsar PSR J0007+7303 and its X-ray pulsar wind nebula (PWN). The photon spectrum is well described by a power-law dN/dE = N 0(E/3 TeV)–Γ, with a differential spectral index of Γ = 2.2 ± 0.2stat ± 0.3sys, and normalization N 0 = (9.1 ± 1.3stat ± 1.7sys× 10–14 cm–2 s–1 TeV–1. The integral flux, F γ = 4.0 ×10–12 erg cm–2 s–1 above 1 TeV, corresponds to 0.2% of the pulsar spin-down power at 1.4 kpc. The energetics, colocation with the SNR, and the relatively small extent of the TeV emission strongly argue for the PWN origin of the TeV photons. We consider the origin of the TeV emission in CTA 1.

  • 428. Aliu, E.
    et al.
    Archambault, S.
    Arlen, T.
    Aune, T.
    Beilicke, M.
    Benbow, W.
    Böttcher, M.
    Bouvier, A.
    Bradbury, S. M.
    Buckley, J. H.
    Bugaev, V.
    Byrum, K.
    Cannon, A.
    Cesarini, A.
    Ciupik, L.
    Collins-Hughes, E.
    Connolly, M. P.
    Coppi, P.
    Cui, W.
    Decerprit, G.
    Dickherber, R.
    Dumm, J.
    Errando, M.
    Falcone, A.
    Feng, Q.
    Finley, J. P.
    Finnegan, G.
    Fortson, L.
    Furniss, A.
    Galante, N.
    Gall, D.
    Godambe, S.
    Griffin, S.
    Grube, J.
    Gyuk, G.
    Hanna, D.
    Hawkins, K.
    Holder, J.
    Huan, H.
    Hughes, G.
    Humensky, T. B.
    Kaaret, P.
    Karlsson, N.
    Kertzman, M.
    Khassen, Y.
    Kieda, D.
    Krawczynski, H.
    Krennrich, F.
    Lang, M. J.
    Lee, K.
    Madhavan, A. S.
    Maier, G.
    Majumdar, P.
    McArthur, S.
    McCann, A.
    Moriarty, P.
    Mukherjee, R.
    Ong, R. A.
    Orr, M.
    Otte, A. N.
    Palma, N.
    Park, N.
    Perkins, J. S.
    Pichel, A.
    Pohl, M.
    Prokoph, Heike
    DESY, Germany.
    Quinn, J.
    Ragan, K.
    Reyes, L. C.
    Reynolds, P. T.
    Roache, E.
    Rose, H. J.
    Ruppel, J.
    Saxon, D. B.
    Schroedter, M.
    Sembroski, G. H.
    \c Sentürk, G. D.
    Smith, A. W.
    Staszak, D.
    Telezhinsky, I.
    Tesić, G.
    Theiling, M.
    Thibadeau, S.
    Tsurusaki, K.
    Varlotta, A.
    Vivier, M.
    Wakely, S. P.
    Ward, J. E.
    Weekes, T. C.
    Weinstein, A.
    Weisgarber, T.
    Williams, D. A.
    Zitzer, B.
    Fortin, P.
    Horan, D.
    Discovery of High-energy and Very High Energy γ-Ray Emission from the Blazar RBS 04132012Inngår i: Astrophysical Journal, ISSN 0004-637X, E-ISSN 1538-4357, Vol. 750, nr 2, artikkel-id 94Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We report on the discovery of high-energy (HE; E > 0.1 GeV) and very high energy (VHE; E > 100 GeV) γ-ray emission from the high-frequency-peaked BL Lac object RBS 0413. VERITAS, a ground-based γ-ray observatory, detected VHE γ rays from RBS 0413 with a statistical significance of 5.5 standard deviations (σ) and a γ-ray flux of (1.5 ± 0.6stat ± 0.7syst× 10–8 photons m–2 s–1 (~1% of the Crab Nebula flux) above 250 GeV. The observed spectrum can be described by a power law with a photon index of 3.18 ± 0.68stat ± 0.30syst. Contemporaneous observations with the Large Area Telescope (LAT) on the Fermi Gamma-ray Space Telescope detected HE γ rays from RBS 0413 with a statistical significance of more than 9σ, a power-law photon index of 1.57 ± 0.12stat +0.11 – 0.12sys, and a γ-ray flux between 300 MeV and 300 GeV of (1.64 ± 0.43stat +0.31 – 0.22sys× 10–5photons m–2 s–1. We present the results from Fermi-LAT and VERITAS, including a spectral energy distribution modeling of the γ-ray, quasi-simultaneous X-ray (Swift-XRT), ultraviolet (Swift-UVOT), and R-band optical (MDM) data. We find that, if conditions close to equipartition are required, both the combined synchrotron self-Compton/external-Compton and the lepto-hadronic models are preferred over a pure synchrotron self-Compton model.

  • 429. Aliu, E.
    et al.
    Archambault, S.
    Arlen, T.
    Aune, T.
    Beilicke, M.
    Benbow, W.
    Böttcher, M.
    Bouvier, A.
    Buckley, J. H.
    Bugaev, V.
    Cesarini, A.
    Ciupik, L.
    Collins-Hughes, E.
    Connolly, M. P.
    Cui, W.
    Dickherber, R.
    Duke, C.
    Dumm, J.
    Errando, M.
    Falcone, A.
    Federici, S.
    Feng, Q.
    Finley, J. P.
    Finnegan, G.
    Fortson, L.
    Furniss, A.
    Galante, N.
    Gall, D.
    Godambe, S.
    Griffin, S.
    Grube, J.
    Gyuk, G.
    Hanna, D.
    Holder, J.
    Huan, H.
    Kaaret, P.
    Karlsson, N.
    Khassen, Y.
    Kieda, D.
    Krawczynski, H.
    Krennrich, F.
    Lee, K.
    Madhavan, A. S.
    Maier, G.
    Majumdar, P.
    McArthur, S.
    McCann, A.
    Moriarty, P.
    Mukherjee, R.
    Nelson, T.
    O’Faoláin de Bhróithe, A.
    Ong, R. A.
    Orr, M.
    Otte, A. N.
    Park, N.
    Perkins, J. S.
    Pichel, A.
    Pohl, M.
    Prokoph, Heike
    DESY, Germany .
    Quinn, J.
    Ragan, K.
    Reyes, L. C.
    Reynolds, P. T.
    Roache, E.
    Saxon, D. B.
    Sembroski, G. H.
    Staszak, D.
    Telezhinsky, I.
    Tesić, G.
    Theiling, M.
    Thibadeau, S.
    Tsurusaki, K.
    Varlotta, A.
    Vassiliev, V. V.
    Vincent, S.
    Vivier, M.
    Wakely, S. P.
    Weekes, T. C.
    Weinstein, A.
    Welsing, R.
    Williams, D. A.
    Zitzer, B.
    Collaboration, V E R I T A S
    Fortin, P.
    Horan, D.
    Fumagalli, M.
    Kaplan, K.
    Prochaska, J. X.
    VERITAS Observations of Six Bright, Hard-spectrum Fermi-LAT Blazars2012Inngår i: Astrophysical Journal, ISSN 0004-637X, E-ISSN 1538-4357, Vol. 759, nr 2, artikkel-id 102Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We report on VERITAS very high energy (VHE; E ≥ 100 GeV) observations of six blazars selected from the Fermi Large Area Telescope First Source Catalog (1FGL). The gamma-ray emission from 1FGL sources was extrapolated up to the VHE band, taking gamma-ray absorption by the extragalactic background light into account. This allowed the selection of six bright, hard-spectrum blazars that were good candidate TeV emitters. Spectroscopic redshift measurements were attempted with the Keck Telescope for the targets without Sloan Digital Sky Survey spectroscopic data. No VHE emission is detected during the observations of the six sources described here. Corresponding TeV upper limits are presented, along with contemporaneousFermi observations and non-concurrent Swift UVOT and X-Ray Telescope data. The blazar broadband spectral energy distributions (SEDs) are assembled and modeled with a single-zone synchrotron self-Compton model. The SED built for each of the six blazars shows a synchrotron peak bordering between the intermediate- and high-spectrum-peak classifications, with four of the six resulting in particle-dominated emission regions.

  • 430. Aliu, E.
    et al.
    Archambault, S.
    Aune, T.
    Behera, B.
    Beilicke, M.
    Benbow, W.
    Berger, K.
    Bird, R.
    Bouvier, A.
    Buckley, J. H.
    Bugaev, V.
    Byrum, K.
    Cerruti, M.
    Chen, X.
    Ciupik, L.
    Connolly, M. P.
    Cui, W.
    Duke, C.
    Dumm, J.
    Errando, M.
    Falcone, A.
    Federici, S.
    Feng, Q.
    Finley, J. P.
    Fortin, P.
    Fortson, L.
    Furniss, A.
    Galante, N.
    Gillanders, G. H.
    Griffin, S.
    Griffiths, S. T.
    Grube, J.
    Gyuk, G.
    Hanna, D.
    Holder, J.
    Hughes, G.
    Humensky, T. B.
    Kaaret, P.
    Kertzman, M.
    Khassen, Y.
    Kieda, D.
    Krawczynski, H.
    Krennrich, F.
    Lang, M. J.
    Madhavan, A. S.
    Maier, G.
    Majumdar, P.
    McCann, A.
    Moriarty, P.
    Mukherjee, R.
    Nieto, D.
    de Bhroithe, A. O'Faolain
    Ong, R. A.
    Otte, A. N.
    Park, N.
    Perkins, J. S.
    Pohl, M.
    Popkow, A.
    Prokoph, Heike
    Quinn, J.
    Ragan, K.
    Rajotte, J.
    Reyes, L. C.
    Reynolds, P. T.
    Richards, G. T.
    Roache, E.
    Rousselle, J.
    Sembroski, G. H.
    Sheidaei, F.
    Skole, C.
    Smith, A. W.
    Staszak, D.
    Stroh, M.
    Telezhinsky, I.
    Theiling, M.
    Tucci, J. V.
    Tyler, J.
    Varlotta, A.
    Vincent, S.
    Wakely, S. P.
    Weinstein, A.
    Welsing, R.
    Williams, D. A.
    Zajczyk, A.
    Zitzer, B.
    Abramowski, A.
    Aharonian, F.
    Benkhali, F. Ait
    Akhperjanian, A. G.
    Anguener, E.
    Anton, G.
    Balenderan, S.
    Balzer, A.
    Barnacka, A.
    Becherini, Yvonne
    Heidelberg Univ, Germany.
    Tjus, J. Becker
    Bernloehr, K.
    Birsin, E.
    Bissaldi, E.
    Biteau, J.
    Boettcher, M.
    Boisson, C.
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    Bordas, P.
    Brucker, J.
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    Casanova, S.
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    Poon, H.
    Puehlhofer, G.
    Punch, Michael
    niv Paris Diderot, APC, AstroParticule & Cosmology, CNRS,IN2P3,CEA,Irfu, Observ Paris,Sorbonne Paris C, 10 Rue Alice Domon & Leonie Duquet, F-75205 Paris 13, France.
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    Zech, A.
    Zechlin, H. -S
    Long-term TeV and X-ray Observations of the Gamma-ray Binary HESS J0632+0572014Inngår i: Astrophysical Journal, ISSN 0004-637X, E-ISSN 1538-4357, Vol. 780, nr 2, artikkel-id 168Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    HESS J0632+057 is the only gamma-ray binary known so far whose position in the sky allows observations with ground-based observatories in both thenorthern and southern hemispheres. Here we report on long-term observations of HESS J0632+057 conducted with the Very Energetic Radiation Imaging Telescope Array System and High Energy Stereoscopic System Cherenkov telescopes and the X-ray satellite Swift, spanning a time range from 2004 to 2012 and covering most of the system's orbit. The very-high-energy (VHE) emission is found to be variable and is correlated with that at X-ray energies. An orbital period of 315(-4)(+6) days is derived from the X-ray data set, which is compatible with previous results, P = (321 +/- 5) days. The VHE light curve shows a distinct maximum at orbital phases close to 0.3, or about 100 days after periastron passage, which coincides with the periodic enhancement of the X-rayemission. Furthermore, the analysis of the TeV data shows for the first time a statistically significant (> 6.5 sigma) detection at orbital phases 0.6-0.9. Theobtained gamma-ray and X-ray light curves and the correlation of the source emission at these two energy bands are discussed in the context of the recent ephemeris obtained for the system. Our results are compared to those reported for other gamma-ray binaries.

  • 431. Aliu, E.
    et al.
    Archambault, S.
    Aune, T.
    Behera, B.
    Beilicke, M.
    Benbow, W.
    Berger, K.
    Bird, R.
    Buckley, J. H.
    Bugaev, V.
    Cardenzana, J. V.
    Cerruti, M.
    Chen, X.
    Ciupik, L.
    Collins-Hughes, E.
    Connolly, M. P.
    Cui, W.
    Dumm, J.
    Dwarkadas, V. V.
    Errando, M.
    Falcone, A.
    Federici, S.
    Feng, Q.
    Finley, J. P.
    Fleischhack, H.
    Fortin, P.
    Fortson, L.
    Furniss, A.
    Galante, N.
    Gall, D.
    Gillanders, G. H.
    Griffin, S.
    Griffiths, S. T.
    Grube, J.
    Gyuk, G.
    Hanna, D.
    Holder, J.
    Hughes, G.
    Humensky, T. B.
    Kaaret, P.
    Kertzman, M.
    Khassen, Y.
    Kieda, D.
    Krennrich, F.
    Kumar, S.
    Lang, M. J.
    Madhavan, A. S.
    Maier, G.
    McCann, A. J.
    Meagher, K.
    Millis, J.
    Moriarty, P.
    Mukherjee, R.
    Nieto, D.
    O’Faoláin de Bhróithe, A.
    Ong, R. A.
    Otte, A. N.
    Pandel, D.
    Park, N.
    Pohl, M.
    Popkow, A.
    Prokoph, Heike
    DESY, Germany .
    Quinn, J.
    Ragan, K.
    Rajotte, J.
    Ratliff, G.
    Reyes, L. C.
    Reynolds, P. T.
    Richards, G. T.
    Roache, E.
    Rousselle, J.
    Sembroski, G. H.
    Shahinyan, K.
    Sheidaei, F.
    Smith, A. W.
    Staszak, D.
    Telezhinsky, I.
    Tsurusaki, K.
    Tucci, J. V.
    Tyler, J.
    Varlotta, A.
    Vassiliev, V. V.
    Vincent, S.
    Wakely, S. P.
    Ward, J. E.
    Weinstein, A.
    Welsing, R.
    Wilhelm, A.
    Investigating the TeV Morphology of MGRO J1908+06 with VERITAS2014Inngår i: Astrophysical Journal, ISSN 0004-637X, E-ISSN 1538-4357, Vol. 787, nr 2, artikkel-id 166Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We report on deep observations of the extended TeV gamma-ray source MGRO J1908+06 made with the VERITAS very high energy gamma-ray observatory. Previously, the TeV emission has been attributed to the pulsar wind nebula (PWN) of theFermi-LAT pulsar PSR J1907+0602. We detect MGRO J1908+06 at a significance level of 14 standard deviations (14σ) and measure a photon index of 2.20 ± 0.10stat ± 0.20sys. The TeV emission is extended, covering the region near PSR J1907+0602 and also extending toward SNR G40.5-0.5. When fitted with a two-dimensional Gaussian, the intrinsic extension has a standard deviation of σsrc = 044 ± 002. In contrast to other TeV PWNe of similar age in which the TeV spectrum softens with distance from the pulsar, the TeV spectrum measured near the pulsar location is consistent with that measured at a position near the rim of G40.5-0.5, 033 away.

  • 432. Aliu, E.
    et al.
    Archambault, S.
    Behera, B.
    Berger, K.
    Beilicke, M.
    Benbow, W.
    Bird, R.
    Bouvier, A.
    Bugaev, V.
    Cerruti, M.
    Chen, X.
    Ciupik, L.
    Connolly, M. P.
    Cui, W.
    Dumm, J.
    Falcone, A.
    Federici, S.
    Feng, Q.
    Finley, J. P.
    Fortin, P.
    Fortson, L.
    Furniss, A.
    Galante, N.
    Gillanders, G. H.
    Griffin, S.
    Griffiths, S. T.
    Grube, J.
    Gyuk, G.
    Hanna, D.
    Holder, J.
    Hughes, G.
    Humensky, T. B.
    Kaaret, P.
    Kertzman, M.
    Khassen, Y.
    Kieda, D.
    Krennrich, F.
    Lang, M. J.
    Maier, G.
    Majumdar, P.
    McArthur, S.
    McCann, A.
    Moriarty, P.
    Mukherjee, R.
    O’Faoláin de Bhróithe, A.
    Ong, R. A.
    Otte, A. N.
    Park, N.
    Perkins, J. S.
    Pohl, M.
    Popkow, A.
    Prokoph, Heike
    DESY, Germany.
    Quinn, J.
    Ragan, K.
    Rajotte, J.
    Ratliff, G.
    Reynolds, P. T.
    Richards, G. T.
    Roache, E.
    Sembroski, G. H.
    Sheidaei, F.
    Skole, C.
    Smith, A. W.
    Staszak, D.
    Telezhinsky, I.
    Tyler, J.
    Varlotta, A.
    Vincent, S.
    Wakely, S. P.
    Weekes, T. C.
    Weinstein, A.
    Welsing, R.
    Zajczyk, A.
    Zitzer, B.
    Multiwavelength Observations of the TeV Binary LS I +61° 303 with VERITAS, Fermi-LAT, and Swift/XRT during a TeV Outburst2013Inngår i: Astrophysical Journal, ISSN 0004-637X, E-ISSN 1538-4357, Vol. 779, nr 1, artikkel-id 88Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We present the results of a multiwavelength observational campaign on the TeV binary system LS I +61° 303 with the VERITAS telescope array (>200 GeV), Fermi-LAT (0.3-300 GeV), and Swift/XRT (2-10 keV). The data were taken from 2011 December through 2012 January and show a strong detection in all three wavebands. During this period VERITAS obtained 24.9 hr of quality selected livetime data in which LS I +61° 303 was detected at a statistical significance of 11.9σ. These TeV observations show evidence for nightly variability in the TeV regime at a post-trial significance of 3.6σ. The combination of the simultaneously obtained TeV and X-ray fluxes do not demonstrate any evidence for a correlation between emission in the two bands. For the first time since the launch of the Fermi satellite in 2008, this TeV detection allows the construction of a detailed MeV-TeV spectral energy distribution from LS I +61° 303. This spectrum shows a distinct cutoff in emission near 4 GeV, with emission seen by the VERITAS observations following a simple power-law above 200 GeV. This feature in the spectrum of LS I +61° 303, obtained from overlapping observations with Fermi-LAT and VERITAS, may indicate that there are two distinct populations of accelerated particles producing the GeV and TeV emission.

  • 433. Aliu, E.
    et al.
    Arlen, T.
    Aune, T.
    Beilicke, M.
    Benbow, W.
    Bouvier, A.
    Bradbury, S. M.
    Buckley, J. H.
    Bugaev, V.
    Byrum, K.
    Cannon, A.
    Cesarini, A.
    Ciupik, L.
    Collins-Hughes, E.
    Connolly, M. P.
    Cui, W.
    Dickherber, R.
    Duke, C.
    Errando, M.
    Falcone, A.
    Finley, J. P.
    Finnegan, G.
    Fortson, L.
    Furniss, A.
    Galante, N.
    Gall, D.
    Godambe, S.
    Griffin, S.
    Grube, J.
    Guenette, R.
    Gyuk, G.
    Hanna, D.
    Holder, J.
    Huan, H.
    Hughes, G.
    Hui, C. M.
    Humensky, T. B.
    Imran, A.
    Kaaret, P.
    Karlsson, N.
    Kertzman, M.
    Kieda, D.
    Krawczynski, H.
    Krennrich, F.
    Lang, M. J.
    LeBohec, S.
    Madhavan, A. S.
    Maier, G.
    Majumdar, P.
    McArthur, S.
    McCann, A.
    Moriarty, P.
    Mukherjee, R.
    Nuñez, P. D.
    Ong, R. A.
    Orr, M.
    Otte, A. N.
    Park, N.
    Perkins, J. S.
    Pichel, A.
    Pohl, M.
    Prokoph, Heike
    DESY, Germany .
    Quinn, J.
    Ragan, K.
    Reyes, L. C.
    Reynolds, P. T.
    Roache, E.
    Rose, H. J.
    Ruppel, J.
    Saxon, D. B.
    Schroedter, M.
    Sembroski, G. H.
    \c Sentürk, G. D.
    Skole, C.
    Staszak, D.
    Te\v sić, G.
    Theiling, M.
    Thibadeau, S.
    Tsurusaki, K.
    Tyler, J.
    Varlotta, A.
    Vassiliev, V. V.
    Vincent, S.
    Vivier, M.
    Wakely, S. P.
    Ward, J. E.
    Weekes, T. C.
    Weinstein, A.
    Weisgarber, T.
    Williams, D. A.
    Zitzer, B.
    VERITAS Observations of Day-scale Flaring of M 87 in 2010 April2012Inngår i: Astrophysical Journal, ISSN 0004-637X, E-ISSN 1538-4357, Vol. 746, nr 2, artikkel-id 141Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    VERITAS has been monitoring the very-high-energy (VHE; > 100 GeV) gamma-ray activity of the radio galaxy M 87 since 2007. During 2008, flaring activity on a timescale of a few days was observed with a peak flux of (0.70 ± 0.16) × 10–11 cm–2 s–1 at energies above 350 GeV. In 2010 April, VERITAS detected a flare from M 87 with peak flux of (2.71 ± 0.68) × 10–11 cm–2 s–1 forE > 350 GeV. The source was observed for six consecutive nights during the flare, resulting in a total of 21 hr of good-quality data. The most rapid flux variation occurred on the trailing edge of the flare with an exponential flux decay time of 0.90+0.22 –0.15 days. The shortest detected exponential rise time is three times as long, at 2.87+1.65 –0.99 days. The quality of the data sample is such that spectral analysis can be performed for three periods: rising flux, peak flux, and falling flux. The spectra obtained are consistent with power-law forms. The spectral index at the peak of the flare is equal to 2.19 ± 0.07. There is some indication that the spectrum is softer in the falling phase of the flare than the peak phase, with a confidence level corresponding to 3.6 standard deviations. We discuss the implications of these results for the acceleration and cooling rates of VHE electrons in M 87 and the constraints they provide on the physical size of the emitting region.

  • 434. Aliu, E.
    et al.
    Arlen, T.
    Aune, T.
    Beilicke, M.
    Benbow, W.
    Böttcher, M.
    Bouvier, A.
    Bradbury, S. M.
    Buckley, J. H.
    Bugaev, V.
    Cannon, A.
    Cesarini, A.
    Ciupik, L.
    Collins-Hughes, E.
    Connolly, M. P.
    Cui, W.
    Dickherber, R.
    Errando, M.
    Falcone, A.
    Finley, J. P.
    Fortson, L.
    Furniss, A.
    Galante, N.
    Gall, D.
    Gillanders, G. H.
    Godambe, S.
    Griffin, S.
    Grube, J.
    Gyuk, G.
    Hanna, D.
    Holder, J.
    Huan, H.
    Hughes, G.
    Hui, C. M.
    Humensky, T. B.
    Kaaret, P.
    Karlsson, N.
    Kertzman, M.
    Kieda, D.
    Krawczynski, H.
    Krennrich, F.
    Madhavan, A. S.
    Maier, G.
    Majumdar, P.
    McArthur, S.
    McCann, A.
    Moriarty, P.
    Mukherjee, R.
    Ong, R. A.
    Orr, M.
    Otte, A. N.
    Park, N.
    Perkins, J. S.
    Pichel, A.
    Pohl, M.
    Prokoph, Heike
    DESY, Germany.
    Quinn, J.
    Ragan, K.
    Reyes, L. C.
    Reynolds, P. T.
    Roache, E.
    Rose, H. J.
    Ruppel, J.
    Saxon, D. B.
    Schroedter, M.
    Sembroski, G. H.
    Skole, C.
    Smith, A. W.
    Staszak, D.
    Te\v sić, G.
    Theiling, M.
    Thibadeau, S.
    Tsurusaki, K.
    Tyler, J.
    Varlotta, A.
    Vincent, S.
    Vivier, M.
    Wakely, S. P.
    Ward, J. E.
    Weinstein, A.
    Weisgarber, T.
    Williams, D. A.
    VERITAS Observations of the Unusual Extragalactic Transient Swift J164449.3+5734512011Inngår i: Astrophysical Journal Letters, ISSN 2041-8205, E-ISSN 2041-8213, Vol. 738, nr 2, artikkel-id L30Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We report on very high energy (>100 GeV) gamma-ray observations of Swift J164449.3+573451, an unusual transient object first detected by the Swift Observatory and later detected by multiple radio, optical, and X-ray observatories. A total exposure of 28 hr was obtained on Swift J164449.3+573451 with the Very Energetic Radiation Imaging Telescope Array System (VERITAS) during 2011 March 28-April 15. We do not detect the source and place a differential upper limit on the emission at 500 GeV during these observations of 1.4 × 10–12 erg cm–2 s–1 (99% confidence level). We also present time-resolved upper limits and use a flux limit averaged over the X-ray flaring period to constrain various emission scenarios that can accommodate both the radio-through-X-ray emission detected from the source and the lack of detection by VERITAS.

  • 435. Aliu, E.
    et al.
    Aune, T.
    Barnacka, A.
    Beilicke, M.
    Benbow, W.
    Berger, K.
    Biteau, J.
    Buckley, J. H.
    Bugaev, V.
    Byrum, K.
    Cardenzana, J. V.
    Cerruti, M.
    Chen, X.
    Ciupik, L.
    Connaughton, V.
    Cui, W.
    Dickinson, H. J.
    Eisch, J. D.
    Errando, M.
    Falcone, A.
    Federici, S.
    Feng, Q.
    Finley, J. P.
    Fleischhack, H.
    Fortin, P.
    Fortson, L.
    Furniss, A.
    Galante, N.
    Gillanders, G. H.
    Griffin, S.
    Griffiths, S. T.
    Grube, J.
    Gyuk, G.
    Håkansson, N.
    Hanna, D.
    Holder, J.
    Hughes, G.
    Humensky, T. B.
    Johnson, C. A.
    Kaaret, P.
    Kar, P.
    Kertzman, M.
    Khassen, Y.
    Kieda, D.
    Krawczynski, H.
    Krennrich, F.
    Lang, M. J.
    Madhavan, A. S.
    Maier, G.
    McArthur, S.
    McCann, A.
    Meagher, K.
    Millis, J.
    Moriarty, P.
    Mukherjee, R.
    Nieto, D.
    O’Faoláin de Bhróithe, A.
    Ong, R. A.
    Otte, A. N.
    Park, N.
    Pohl, M.
    Popkow, A.
    Prokoph, Heike
    DESY, Germany .
    Pueschel, E.
    Quinn, J.
    Ragan, K.
    Rajotte, J.
    Reyes, L. C.
    Reynolds, P. T.
    Richards, G. T.
    Roache, E.
    Sembroski, G. H.
    Shahinyan, K.
    Smith, A. W.
    Staszak, D.
    Telezhinsky, I.
    Tucci, J. V.
    Tyler, J.
    Varlotta, A.
    Vassiliev, V. V.
    Vincent, S.
    Wakely, S. P.
    Weiner, O. M.
    Weinstein, A.
    Welsing, R.
    Wilhelm, A.
    Williams, D. A.
    Zitzer, B.
    McEnery, J. E.
    Perkins, J. S.
    Veres, P.
    Zhu, S.
    Constraints on Very High Energy Emission from GRB 130427A2014Inngår i: Astrophysical Journal Letters, ISSN 2041-8205, E-ISSN 2041-8213, Vol. 795, nr 1, artikkel-id L3Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Prompt emission from the very fluent and nearby (z = 0.34) gamma-ray burst GRB 130427A was detected by several orbiting telescopes and by ground-based, wide-field-of-view optical transient monitors. Apart from the intensity and proximity of this GRB, it is exceptional due to the extremely long-lived high-energy (100 MeV to 100 GeV) gamma-ray emission, which was detected by the Large Area Telescope on the Fermi Gamma-Ray Space Telescope for ~70 ks after the initial burst. The persistent, hard-spectrum, high-energy emission suggests that the highest-energy gamma rays may have been produced via synchrotron self-Compton processes though there is also evidence that the high-energy emission may instead be an extension of the synchrotron spectrum. VERITAS, a ground-based imaging atmospheric Cherenkov telescope array, began follow-up observations of GRB 130427A ~71 ks (~20 hr) after the onset of the burst. The GRB was not detected with VERITAS; however, the high elevation of the observations, coupled with the low redshift of the GRB, make VERITAS a very sensitive probe of the emission from GRB 130427A for E > 100 GeV. The non-detection and consequent upper limit derived place constraints on the synchrotron self-Compton model of high-energy gamma-ray emission from this burst.

  • 436. Aliu, E.
    et al.
    Aune, T.
    Behera, B.
    Beilicke, M.
    Benbow, W.
    Berger, K.
    Bird, R.
    Buckley, J. H.
    Bugaev, V.
    Cardenzana, J. V.
    Cerruti, M.
    Chen, X.
    Ciupik, L.
    Connolly, M. P.
    Cui, W.
    Duke, C.
    Dumm, J.
    Errando, M.
    Falcone, A.
    Federici, S.
    Feng, Q.
    Finley, J. P.
    Fortin, P.
    Fortson, L.
    Furniss, A.
    Galante, N.
    Gillanders, G. H.
    Griffin, S.
    Griffiths, S. T.
    Grube, J.
    Gyuk, G.
    Hanna, D.
    Holder, J.
    Hughes, G.
    Humensky, T. B.
    Kaaret, P.
    Kargaltsev, O.
    Kertzman, M.
    Khassen, Y.
    Kieda, D.
    Krawczynski, H.
    Lang, M. J.
    Madhavan, A. S.
    Maier, G.
    Majumdar, P.
    McCann, A.
    Moriarty, P.
    Mukherjee, R.
    Nieto, D.
    O’Faoláin de Bhróithe, A.
    Ong, R. A.
    Otte, A. N.
    Pandel, D.
    Perkins, J. S.
    Pohl, M.
    Popkow, A.
    Prokoph, Heike
    DESY, Germany .
    Quinn, J.
    Ragan, K.
    Rajotte, J.
    Reyes, L. C.
    Reynolds, P. T.
    Richards, G. T.
    Roache, E.
    Sembroski, G. H.
    Skole, C.
    Staszak, D.
    Telezhinsky, I.
    Theiling, M.
    Tucci, J. V.
    Tyler, J.
    Varlotta, A.
    Vincent, S.
    Wakely, S. P.
    Weekes, T. C.
    Weinstein, A.
    Welsing, R.
    Williams, D. A.
    Zitzer, B.
    Observations of the Unidentified Gamma-Ray Source TeV J2032+4130 by VERITAS2014Inngår i: Astrophysical Journal, ISSN 0004-637X, E-ISSN 1538-4357, Vol. 783Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    TeV J2032+4130 was the first unidentified source discovered at very high energies (VHEs; E > 100 GeV), with no obvious counterpart in any other wavelength. It is also the first extended source to be observed in VHE gamma rays. Following its discovery, intensive observational campaigns have been carried out in all wavelengths in order to understand the nature of the object, which have met with limited success. We report here on a deep observation of TeV J2032+4130   based on 48.2 hr of data taken from 2009 to 2012 by the Very Energetic Radiation Imaging Telescope Array System experiment. The source is detected at 8.7 standard deviations (σ) and is found to be extended and asymmetric with a width of 9.'5 ± 1.'2 along the major axis and 4.'0 ± 0.'5 along the minor axis. The spectrum is well described by a differential power law with an index of 2.10 ± 0.14stat ± 0.21sys and a normalization of (9.5 ± 1.6stat ± 2.2sys× 10–13 TeV–1 cm–2 s–1 at 1 TeV. We interpret these results in the context of multiwavelength scenarios which particularly favor the pulsar wind nebula interpretation.

  • 437. Aliu, E.
    et al.
    Aune, T.
    Beilicke, M.
    Benbow, W.
    Böttcher, M.
    Bouvier, A.
    Bradbury, S. M.
    Buckley, J. H.
    Bugaev, V.
    Cannon, A.
    Cesarini, A.
    Ciupik, L.
    Connolly, M. P.
    Cui, W.
    Decerprit, G.
    Dickherber, R.
    Duke, C.
    Errando, M.
    Falcone, A.
    Feng, Q.
    Finnegan, G.
    Fortson, L.
    Furniss, A.
    Galante, N.
    Gall, D.
    Gillanders, G. H.
    Godambe, S.
    Griffin, S.
    Grube, J.
    Gyuk, G.
    Hanna, D.
    Hivick, B.
    Holder, J.
    Huan, H.
    Hughes, G.
    Hui, C. M.
    Humensky, T. B.
    Kaaret, P.
    Karlsson, N.
    Kertzman, M.
    Kieda, D.
    Krawczynski, H.
    Krennrich, F.
    Maier, G.
    Majumdar, P.
    McArthur, S.
    McCann, A.
    Moriarty, P.
    Mukherjee, R.
    Nelson, T.
    Ong, R. A.
    Orr, M.
    Otte, A. N.
    Park, N.
    Perkins, J. S.
    Pichel, A.
    Pohl, M.
    Prokoph, Heike
    DESY, Germany.
    Quinn, J.
    Ragan, K.
    Reyes, L. C.
    Reynolds, P. T.
    Roache, E.
    Rose, H. J.
    Ruppel, J.
    Saxon, D. B.
    Sembroski, G. H.
    Skole, C.
    Smith, A. W.
    Staszak, D.
    Tesić, G.
    Theiling, M.
    Thibadeau, S.
    Tsurusaki, K.
    Tyler, J.
    Varlotta, A.
    Vassiliev, V. V.
    Wakely, S. P.
    Weekes, T. C.
    Weinstein, A.
    Williams, D. A.
    Zitzer, B.
    Collaboration, V E R I T A S
    Ciprini, S.
    Fumagalli, M.
    Kaplan, K.
    Paneque, D.
    Prochaska, J. X.
    Multiwavelength Observations of the Previously Unidentified Blazar RX J0648.7+15162011Inngår i: Astrophysical Journal, ISSN 0004-637X, E-ISSN 1538-4357, Vol. 742, nr 2, artikkel-id 127Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We report on the VERITAS discovery of very high energy (VHE) gamma-ray emission above 200 GeV from the high-frequency-peaked BL Lac (HBL) object RX J0648.7+1516 (GB J0648+1516), associated with 1FGL J0648.8+1516. The photon spectrum above 200 GeV is fitted by a power law dN/dE = F 0(E/E 0)–Γ with a photon index Γ of 4.4 ± 0.8stat ± 0.3syst and a flux normalization F 0 of (2.3 ± 0.5stat ± 1.2sys× 10–11 TeV–1 cm–2 s–1 with E 0 = 300 GeV. No VHE variability is detected during VERITAS observations of RX J0648.7+1516 between 2010 March 4 and April 15. Following the VHE discovery, the optical identification and spectroscopic redshift were obtained using the Shane 3 m Telescope at the Lick Observatory, showing the unidentified object to be a BL Lac type with a redshift of z = 0.179. Broadband multiwavelength observations contemporaneous with the VERITAS exposure period can be used to subclassify the blazar as an HBL object, including data from the MDM observatory, Swift-UVOT, and X-Ray Telescope, and continuous monitoring at photon energies above 1 GeV from the FermiLarge Area Telescope (LAT). We find that in the absence of undetected, high-energy rapid variability, the one-zone synchrotron self-Compton (SSC) model overproduces the high-energy gamma-ray emission measured by the Fermi-LAT over 2.3 years. The spectral energy distribution can be parameterized satisfactorily with an external-Compton or lepto-hadronic model, which have two and six additional free parameters, respectively, compared to the one-zone SSC model.

  • 438.
    Alkhars, Abeer
    et al.
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för datavetenskap (DV).
    Mahmoud, Wasan
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för datavetenskap (DV).
    Cross-Platform Desktop Development (JavaFX vs. Electron)2017Independent thesis Basic level (degree of Bachelor), 10 poäng / 15 hpOppgave
    Abstract [en]

    Today, there are many technologies available for developing cross-platform desktop apps. JavaFX is a software platform based on the Java language. It has a set of features that play a role in its success. On the other hand, Electron is a new framework that allows developers to employ web technologies (JavaScript, HTML, and CSS) to create cross-platform desktop applications. This thesis describes and compares between these two frameworks. The purpose of this report is to provide guidance in choosing the right technique for a particular cross-platform desktop application. Simple cross-platform desktop applications have been developed to compare both approaches as well as find the advantages and disadvantages. The results show that both apps satisfied the functional and nonfunctional requirements. Each framework architecture has its own advantage in building particular apps. Both frameworks have rich APIs as well as rich GUI components for building desktop apps. Electron has good documentation and community help, but it cannot be compared to JavaFX. The Electron app gives faster execution time and less memory usage than JavaFX app. However, the implementation of OOP concepts in Electron using JavaScript has some concerns in terms of encapsulation and inheritance. 

    Fulltekst (pdf)
    fulltext
  • 439.
    Alkmark, Niklas
    Växjö universitet, Fakulteten för humaniora och samhällsvetenskap, Institutionen för pedagogik.
    Praktisk matematik ur ett lärarperspektiv2006Independent thesis Basic level (degree of Bachelor), 10 poäng / 15 hpOppgave
    Abstract [sv]

    Abstract: I rapporten intervjuas fyra mellanstadielärare på en 4-6 skola i Borås stad, om deras syn på praktisk matematik. I vilken utsträckning använder sig lärarna av praktisk matematik, när använder dom det, hur ser de på själva uppgiften samt om uppgifterna ökar elevernas motivation, lust och förståelse för matematik.

    Intervjuerna deklarerar att det finns en stor osäkerhet i hur praktisk matematik skall användas och vilka fördelar den för med sig. Lärarna anser att det bedrivs för lite praktisk matematik på skolan, bokens trygghet lockar allt för mycket. Lärarna poängterar också att vissa områden är lättare än andra att applicera praktisk matematik på. Det finns inte någon direkt uttalad linje när det gäller praktiska moment utan det kommer när det kommer. Däremot är man överens om att lusten och motivationen ofta stärks och att de svaga eleverna får möjlighet att lyckas. Vissa forskare menar att ett praktiskt arbetssätt är helt nödvändigt för att ta upp kunskapen på en ny nivå. Kunskapen måste kunna sättas in i en kontext för att djupinlärning skall erhållas.

    Fulltekst (pdf)
    FULLTEXT01
  • 440.
    All Carreberg, Susanna
    et al.
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för matematik (MA).
    Karlsson, Lina
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för matematik (MA).
    Tal och tanke: hur problemlösningsdiskurser förändras genom samarbete2019Independent thesis Advanced level (degree of Master (One Year)), 10 poäng / 15 hpOppgave
    Abstract [sv]

    Syftet med denna studie är att beskriva processen som sker när elever arbetar tillsammans med en problemlösningsuppgift de tidigare inte kunnat lösa vid enskilt arbete. Fokus har varit på förändrad användning av Sfards (2008) nyckelbegrepp: ämnesspecifika ord, visuella mediatorer, rutiner och berättelser samt vilka diskursförändringar som synliggjorts. Studien är kvalitativ och empirin har samlats in genom observationer av problemlösningsarbetet, ljudinspelningar under pararbeten och bildupptagningar av elevmaterialet. Totalt tio observationer av gemensamt arbete genomfördes och transkriberades och av dessa djupanalyserades fem transkriberingar med hjälp av flödesscheman och Sfards (2008) nyckelbegrepp. Resultatet visar att eleverna i studien använde fler nyckelbegrepp vid den gemensamma problemlösningen och därmed ingick i diskursförändringar som bidrog till att föra problemlösningen framåt. Visuella mediatorer och användningen av tid visade sig vara viktiga aspekter för användning av fler nyckelbegrepp och förändring av diskurser.

    Fulltekst (pdf)
    Tal och tanke
  • 441. Allahverdyan, A
    et al.
    Khrennikov, Andrei
    Växjö universitet, Fakulteten för matematik/naturvetenskap/teknik, Matematiska och systemtekniska institutionen.
    Nieuwenhuizen, Th. M
    Brownian entanglement2005Inngår i: Physical Review A. Atomic, Molecular, and Optical Physics, ISSN 1050-2947, E-ISSN 1094-1622, Vol. 72, s. 032102-Artikkel i tidsskrift (Fagfellevurdert)
  • 442.
    Alldén, Sofie
    Linnéuniversitetet, Fakultetsnämnden för naturvetenskap och teknik, Institutionen för naturvetenskap, NV.
    Utvärdering av näringsstatus inför återskapande av kalkkärr vid Hagebyhöga, Östergötland2011Independent thesis Basic level (degree of Bachelor), 10 poäng / 15 hpOppgave
    Abstract [en]

    Calcareous fens constitute a specific habitat which is uncommon in Europe and protected by the EU habitat directive due to its importance to several threatened species. Hagebyhöga in Östergötland is a calcareous fen habitat included in the Natura 2000 Networking Programme. Adjacent to the existing fen, a degraded fen area is situated. The area has been used for agriculture for several years but is now going to be restored to its former state by the county administrative board of Östergötland.

    When working with restoration of degraded fen areas it is important to aquire knowledge about the chemical soil conditions. Plant growth limited by phosphorus and low fertility are characteristic conditions for calcareous fens, whilst arable land usually is highly fertile and limited by nitrogen.

    The purpose of this study is to bring forth useful knowledge for restoring the degraded calcareous fen of Hagebyhöga. Phytometric assessments have been conducted on samples from the ground that is going to be restored, to investigate which element limits growth, and whether the fertility is comparable to that in the fen allready present. The results will be used when deciding whether the top soil layer needs to be removed, and if that is the case, how much of the soil needs to be removed to recreate the fen environment.

    The samples were collected from two areas (A and B) with different moisture content in the arable ground and three depths from each area (0-10 cm, 10-30 cm and 30-40 cm). As reference, a sample from the top soil layer of the existing fen was used. The results from the phytometric assessment reveals all samples from area A and the sample from area B, 30-40 cm to have plant growth limited by phosphorus. The results also reveals the fertility in all samples except for area A, 30-40 cm to be significantly higher than the fertility of the existing fen. Both conditions, low fertility and plant growth limited by phosphorus, are present in the sample from area A, 30-40 cm.

    Fulltekst (pdf)
    fulltext
  • 443.
    Allender, Chris J.
    et al.
    Cardiff University, UK.
    Andersson, Håkan S.
    Högskolan i Kalmar, Naturvetenskapliga institutionen. Cardiff University, UK.
    Brain, Keith R.
    Cardiff University, UK.
    Ramström, Olof
    Cardiff University, UK.
    Preface2001Inngår i: Analytica Chimica Acta, ISSN 0003-2670, E-ISSN 1873-4324, Vol. 435, nr 1, s. 1-2Artikkel i tidsskrift (Annet vitenskapelig)
  • 444. Allers, E
    et al.
    Gomez-Consarnau, Laura
    Högskolan i Kalmar, Naturvetenskapliga institutionen.
    Pinhassi, Jarone
    Högskolan i Kalmar, Naturvetenskapliga institutionen.
    Simek, K
    Gasol, JM
    Pernthaler, J
    Population dynamics of Alteromonas and Roseobacter in marine mesocosms after substrate and nutrient manipulations2007Inngår i: Environmental Microbiology, ISSN 1462-2912, E-ISSN 1462-2920, Vol. 9, s. 2417-2429Artikkel i tidsskrift (Fagfellevurdert)
  • 445.
    Allmér, Hans
    Linnéuniversitetet, Ekonomihögskolan (FEH), Institutionen för marknadsföring (MF). Åbo Akademi, Finland.
    Digital wellness services' servicescape for young elderly2018Inngår i: 31th Bled eConference Digital Transformation - Meeting the Challanges,Conference Proceedings / [ed] Pucihar, Andreja Kljajic Borstnar, Mirjana Kittl, Christian Ravensteijn, Pascal Clarke, Roger Bons, Roger, Bled, Slovenia: University of Maribor Press , 2018, s. 159-170Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Digital devices reshape the servicescape of wellness, helping people, e.g. young elderly, to benefit from digital wellness services (henceforth DWSs) provided in a digital servicescape. This paper builds on five prior studies and explores: (i) what requirements young elderly have, in order to benefit from DWSs, and (ii) what service providers should consider, and pay regard to, when they develop and offer DWSs to young elderly. Hence, this paper argues for DWSs to be subsets of a digital servicescape. This research developed a model for how different parties, e.g. young elderly, their friends and relatives, developers, providers, but also the society per se, could gain from the DWSs. The DWSs create opportunities for a win-win-win situation. Important for the young elderly are motivation, trust, and credibility. Important for developers and providers are to motivate the users, to create trustworthiness, to provide user guidance, and to develop through co-creation.

  • 446.
    Allmér, Hans
    Åbo Akademi University, Finland.
    Servicescape for Digital Wellness Services for Young Elderly2018Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    In this thesis digital wellness services (DWSs) are in focus. The DWSs are services provided through digital devices, such as smartphones, bracelets, and tablets, by using digital environments such as Internet, cloud services, and websites. They can provide users with information that has an impact on their wellness, such as pulse, nutrition, and training guidance. The focus for this work on DWSs is on the age group of young elderly (60 – 75 years old). They belong to a group who were born long before digital devices and environments emerged and this factor may affect their motivation and willingness to use and benefit from DWSs.

    This thesis offers a framework for a digital servicescape that enables young elderly to benefit from DWSs. DWSs are produced and offered in digital servicescapes, where the interaction between the service providers and the service users occurs. The interaction can take place in different spaces like fitness studios, shopping malls or banks. DWSs for large groups of young elderly will require an ecosystem of stakeholders to develop, distribute, maintain, support, and further develop these services. An ecosystem builds on policies, strategies, processes, information, technologies, applications and stakeholders, and includes people who build, sell, manage and use the system. In order to understand the ecosystem, it is necessary to have a holistic approach to work out how its context, technology, stakeholders, and use interact with each other. A digital servicescape offers the conceptual basis for the ecosystem to form, evolve, and survive and produces platforms on which it is easy, effective, and productive to access and use DWSs.

    The described interaction between digital servicescape and DWSs for improved health leads to the research question: How can a digital servicescape enhance young elderly’s use of Digital Wellness Services (DWSs)?

    In order to answer the research question, the thesis presents different approaches that influence the young elderly’s capabilities and willingness to use and benefit from DWSs. If the young elderly follow recommendations to apply DWSs they will benefit in terms of healthier aging, reduced ill health, and a better quality of life. For developers and providers of DWSs development work will open up business opportunities if they understand the needs and demands of the young elderly. In addition, DWSs can contribute to significant health, social, and economic benefits for society in general. Proactive wellness programs for young elderly will have cumulative effects on the conditions for good health. The digital servicescape is a conceptual framework for future work on actually building the necessary platforms for DWSs.

    The work on this thesis follows an explorative approach. The data collection was carried out through surveys, literature review, and focus groups after which the data was sorted, analysed and interpreted. As the work progressed, a need arose to obtain insights from additional perspectives with the consequence that the additional data contributed to a deeper knowledge of the young elderly, DWSs and digital servicescape.

    The young elderly are, as a group, a very large market consisting of almost 100 million people in Europe alone. For the young elderly, digitalisation has been a part of their lives and its development has provided them with new opportunities to communicate. To them the interface on their digital device is where the interaction with a service provider occurs. Behind the interface, a digital servicescape and an ecosystem provide the necessary tools for the young elderly to achieve the wellness they seek. Nevertheless, to understand the target group it is important to consider four wellness dimensions: i) physical wellness, ii) social wellness, iii) emotional wellness, and iv) intellectual wellness. Together, the four dimensions form a holistic wellness approach to motivate young elderly to use DWSs. The research results show that the young elderly need to be motivated to adopt the services offered. Motivation that affects the young elderly is both intrinsic and extrinsic and this should be considered when developing and providing DWSs and digital servicescapes. Therefore, the service providers have to meet the expectations, needs, and demands of the young elderly and develop services that are suited for the target group. However, this is not enough, as this research shows that the young elderly want to be in a context where they feel safe.

    Information systems offer a basis for communication and interaction with and through digital devices such as smartphones, tablets, and bracelets. The Internet constitutes a platform for service and social interaction. Services offered on the Web, make it possible to do shopping, be entertained, entertain, and be involved in education, research, business and much more. The internet forms an important part of the infrastructure for DWSs and digital servicescapes.

    An efficient and well-designed DWS and its servicescape can create a win-win-win situation. The first part is the young elderly who can benefit from DWSs by increasing their chances of a longer, healthier, and happier life and thereby achieve wellness. The second win situation concerns the service developers and providers who can build a business by designing well-working DWSs aimed at the young elderly. Finally, the third win situation is about family, friends, and society. Well-designed DWSs can be beneficial for family and friends to help the young elderly to achieve wellness and require less support from family and friends. For society in general, there are financial benefits, as healthier and happier young elderly will reduce the demand for health care and support. Together the three win-win-win scenarios build an opportunity for a better tomorrow for all concerned.

     

    This thesis has created a foundation for continued research, testing, and development of DWSs and digital servicescapes. It has shown that there is a need for deeper understanding of the benefits a well-designed servicescape for DWSs can bring to people in general and to the group of young elderly in particular. Furthermore, there is a need for further research in the win-win-win situations when young elderly get access to digital wellness devices. A particularly interesting avenue of research would be to investigate how that digital servicescape could be designed and whether society should provide devices free of charge, at discount or with some other business model.

  • 447. Allwood, Jens
    et al.
    Henrichsen, Peter Juel
    Grönqvist, Leif
    Växjö universitet, Fakulteten för matematik/naturvetenskap/teknik, Matematiska och systemtekniska institutionen.
    Ahlsén, Elisabeth
    Gunnarsson, Magnus
    Transliteration between Spoken Language Corpora: Moving between Danish BySoc and Swedish GSLC2005Inngår i: Nordic Journal of Linguistics, Vol. 28, nr 1, s. 5-36Artikkel i tidsskrift (Fagfellevurdert)
  • 448.
    Almasri, Abdullah
    et al.
    Karlstad University.
    Locking, Håkan
    Linnéuniversitetet, Ekonomihögskolan (FEH), Institutionen för nationalekonomi och statistik (NS).
    Forecasting risk premium using wavelet transform2015Inngår i: Festschrift in honor of Professor Ghazi Shukur on the occasion of his 60th birthday / [ed] Thomas Holgersson, Linnaeus University Press, 2015, 1, s. 1-7Kapittel i bok, del av antologi (Annet vitenskapelig)
  • 449.
    Almasri, Abdullah
    et al.
    Karlstad University.
    Locking, Håkan
    Linnéuniversitetet, Ekonomihögskolan (FEH), Institutionen för nationalekonomi och statistik (NS).
    Shukur, Ghazi
    Linnéuniversitetet, Ekonomihögskolan (FEH), Institutionen för nationalekonomi och statistik (NS). Jönköping University.
    Testing for trends and causality in Swedish environmental data, using Wavelet analysis2013Konferansepaper (Fagfellevurdert)
    Abstract [en]

    This paper utilizes Wavelet based methodology to estimate and test for trends and granger causality in temperature andprecipitation. We use quarterly data from Sweden for the period 1884 up to 2011. The analysis suggests that temperatureand precipitation in Sweden currently have a positive trend in 2011. Thus the recent lower levels of the variables 2009-2010are estimated to be temporary fluctuations or deviations from the trend. Moreover, in the short run there are feedbackeffects between the variables and over longer periods, 4-8 years, temperature granger cause precipitation.

  • 450.
    Almasri, Abdullah
    et al.
    Växjö universitet, Fakulteten för humaniora och samhällsvetenskap, Ekonomihögskolan, EHV.
    Locking, Håkan
    Växjö universitet, Fakulteten för humaniora och samhällsvetenskap, Ekonomihögskolan, EHV.
    Shukur, Ghazi
    Växjö universitet, Fakulteten för humaniora och samhällsvetenskap, Ekonomihögskolan, EHV.
    Wavelet Based Forecasting Approach, with Application2009Inngår i: 2009 International Conference on Financial Theory and Engineering / [ed] Patrick Kellenberger, 2009Konferansepaper (Fagfellevurdert)
    Abstract [en]

    In this paper we outline a framework for forecasting using maximal overlap discrete wavelet transform (MODWT) based multiresoulution analysis (MRA). This framework has been applied for forecasting the tourism arrival series from Denmark to Norway. We compare forecasted values obtained from modeling the data in the time domain with the forecasted values from the wavelet domain using the traditional Box-Jenkins methodology. In both cases, diagnostic tests have been conducted to insure the specification of the model. The results have shown that the wavelet based forecasts outperforms the traditional Box-Jenkins approach in term of forecasts accuracy.

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