Cell-mediated immunity to flavivirus infections

NK cells and T cells constitute a major part of the cell-mediated immune system and play important roles in the host defense against viral infections. Most current knowledge of cell-mediated immune responses to primary acute viral infections comes from murine models, while relatively less is known about human responses to, in particular, acute viral infections. In this thesis, the aim was to explore the early cell- mediated immune responses to acute viral infections in humans. The live attenuated yellow fever virus vaccine (YFV 17D) was used as a human in vivo model to study the dynamics and regulation of NK cell and T cell responses to the infection. In parallel, the NK cell and T cell responses to a natural acute infection caused by tick-borne encephalitis virus (TBEV) were studied. Infection with YFV 17D induced activation of NK cells and T cells. An early activation in NK cell function, around one week post-vaccination, could be observed along with increased functions in response to target cells. A specific effector CD8 T cell response occurred that reached a peak of activation around two weeks post-vaccination, while CD4 T cell activation peaked earlier, around day 10, preceding that of CD8 T cells. The functional profile of the YFV 17D-specific CD8 T cell response changed in composition as it matured from an effector- to a memory-type response, and tended to become less polyfunctional during the course of this transition. In TBEV infected patients, NK cells were activated at the time of hospitalization. The activation subsequently decreased to healthy control levels. Simultaneous activation of CD8 and CD4 T cells occurred at one week following hospitalization and the TBEV-specific CD8 T cells showed a mono- functional profile that persisted over time. Furthermore, TBEV-specific CD8 T cells showed a distinct transcriptional profile in the effector phase of the T cell response. Results presented in this thesis contribute to the understanding of the early T cell and NK cell responses in two human acute viral infections. In addition, they demonstrate that these two flaviviruses induce immune responses with different characteristics in infected humans

Research Expanding Current Understandings of Bullying in Sweden

This paper discusses the on-going research on the phenomenon of bullying in the Department of Child andYouth Studies at Stockholm University. The paper describes the reasons, and how to contribute with anunderstanding of bullying as a social group phenomenon, and specifically focuses on inductive ethnographicand cyberethnographic approaches toward peer-to-peer interactions in schools, preschools and on theInternet. The understanding of this phenomenon is based on a Swedish interdisciplinary approach whichincludes children’s perspectives. The objective is to explore bullying as a complex social group phenomenonwhich allows for a focus on the process of bullying, thus creating an opportunity for the enhancement of theunderstanding of inter- and intra-connected actions and perspectives. This article is intended to contribute toa discussion on a broadening of the conceptualization of the phenomenon of bullying

Public communication campaigns as mundane category

This article examines the public connection and understanding of public communication campaigns. Public communication campaigns are widespread, but the audience dimension of the campaign category itself is still a blind spot in research. Drawing on focus group interviews and a survey among Danish citizens, the article shows that public campaigns are recognized as a mundane communicative category. Moreover, drawing on theories of public connection and governmentality, we show how citizens receive and resist, accept and negotiate public campaigns.&nbsp

Cerebral Venous Thrombosis and Livedo Reticularis in a Case with MTHFR 677TT Homozygote

Hyperhomocysteinemia associated with methylene terahydrofolate reductase (MTHFR) mutation can be a risk factor for idiopathic cerebral venous thrombosis. We describe the first case of MTHFR 677TT homozygote with cerebral venous thrombosis and livedo reticularis. A 45-year-old man presented with seizures and mottled-like skin lesions, that were aggravated by cold temperature. Hemorrhagic infarct in the right frontoparietal area with superior sagittal sinus thrombosis was observed. He had hyperhomocysteinemia, low plasma folate level, and MTHFR 677TT homozygote genotype, which might be associated with livedo reticularis and increase the risk for cerebral venous thrombosis

A review of methods to assess the economic impact of distributed medical education (DME) in Canada

Background: Canadian distributed medical education (DME) increased substantially in the last decade, resulting in positive economic impacts to local communities. A reliable and simple method to estimate economic contributions is essential to provide managers with information on the extent of these impacts. This review paper fills a gap in the literature by answering the question: What are the most applicable quantitative methods to assess the economic impact of Canadian DME programs?Methods: The literature is reviewed to identify economic assessment methods. These are evaluated and compared based on the benefits, challenges, data needs, outputs and potential for use in the DME context.Results: We identified five economic impact methods used in similar contexts. Two of these methods have the potential for Canadian DME programs: the Canadian Input-Output (I-O) model and the Simplified American Council on Education (ACE) method.Conclusion: Choice of a method is contingent on the ability to measure the salient economic impacts, and provide an output that facilitates sustainable decision making. This paper thus fills a gap by identifying methods applicable to DME. These methods will assist stakeholders to calculate economic impacts, resulting in both the advancement and sustainability of these programs over short- and long-term time frames

Fusiform Gyrus Dysfunction is Associated with Perceptual Processing Efficiency to Emotional Faces in Adolescent Depression: A Model-Based Approach

While the extant literature has focused on major depressive disorder (MDD) as being characterized by abnormalities in processing affective stimuli (e.g., facial expressions), little is known regarding which specific aspects of cognition influence the evaluation of affective stimuli, and what are the underlying neural correlates. To investigate these issues, we assessed 26 adolescents diagnosed with MDD and 37 well-matched healthy controls (HCL) who completed an emotion identification task of dynamically morphing faces during functional magnetic resonance imaging (fMRI). We analyzed the behavioral data using a sequential sampling model of response time (RT) commonly used to elucidate aspects of cognition in binary perceptual decision making tasks: the Linear Ballistic Accumulator (LBA) model. Using a hierarchical Bayesian estimation method, we obtained group-level and individual-level estimates of LBA parameters on the facial emotion identification task. While the MDD and HCL groups did not differ in mean RT, accuracy, or group-level estimates of perceptual processing efficiency (i.e., drift rate parameter of the LBA), the MDD group showed significantly reduced responses in left fusiform gyrus compared to the HCL group during the facial emotion identification task. Furthermore, within the MDD group, fMRI signal in the left fusiform gyrus during affective face processing was significantly associated with greater individual-level estimates of perceptual processing efficiency. Our results therefore suggest that affective processing biases in adolescents with MDD are characterized by greater perceptual processing efficiency of affective visual information in sensory brain regions responsible for the early processing of visual information. The theoretical, methodological, and clinical implications of our results are discussed

A Study on Group Key Agreement in Sensor Network Environments Using Two-Dimensional Arrays

These days, with the emergence of the concept of ubiquitous computing, sensor networks that collect, analyze and process all the information through the sensors have become of huge interest. However, sensor network technology fundamentally has wireless communication infrastructure as its foundation and thus has security weakness and limitations such as low computing capacity, power supply limitations and price. In this paper, and considering the characteristics of the sensor network environment, we propose a group key agreement method using a keyset pre-distribution of two-dimension arrays that should minimize the exposure of key and personal information. The key collision problems are resolved by utilizing a polygonal shape’s center of gravity. The method shows that calculating a polygonal shape’s center of gravity only requires a very small amount of calculations from the users. The simple calculation not only increases the group key generation efficiency, but also enhances the sense of security by protecting information between nodes

Pesquisa sobre a expansão do conhecimento atual do bullying na Suécia

This paper discusses the on-going research on the phenomenon of bullying in the Department of Child and Youth Studies at Stockholm University. The paper describes the reasons, and how to contribute with an understanding of bullying as a social group phenomenon, and specifically focuses on inductive ethnographic and cyberethnographic approaches toward peer-to-peer interactions in schools, preschools and on the Internet. The understanding of this phenomenon is based on a Swedish interdisciplinary approach which includes children’s perspectives. The objective is to explore bullying as a complex social group phenomenon which allows for a focus on the process of bullying, thus creating an opportunity for the enhancement of the understanding of inter- and intra-connected actions and perspectives. This article is intended to contribute to a discussion on a broadening of the conceptualization of the phenomenon of bullying.Este documento plantea la investigación permanente sobre el fenómeno de matoneo en el Departamento de Estudios de Niñez y Juventud de la Universidad de Estocolmo. El documento describe las razones, y cómo contribuir con el entendimiento del matoneo como un fenómeno de un grupo social, y específicamente se enfoca en el empleo de etnografía inductiva y ciber-etnografía hacia las interacciones entre pares en los colegios, preescolar y en Internet. La comprensión de este fenómeno se basa en un enfoque interdisciplinario sueco que incluye las perspectivas de los niños. El objetivo es explorar el matoneo como un fenómeno de grupo social complejo, que permite un enfoque en el proceso de matoneo, y por tanto creando una oportunidad de ampliar el entendimiento de acciones y perspectivas inter e intra- conectadas. La intensión de este artículo es contribuir a la discusión de ampliar la conceptualización del fenómeno del bullying.Este artigo discute a pesquisa em curso sobre o fenômeno do bullying no Departamento de Estudos da Criança e da Juventude na Universidade de Estocolmo. O documento descreve as razões, e como contribuir com a compreensão do bullying como um fenômeno social de grupo e, especificamente, enfoca-se em abordagens etnográficas e cyber-etnográficas indutivas sobre interações entre pares em escolas, pré-escolas e internet. A compreensão deste fenômeno está baseado numa abordagem interdisciplinar sueca que inclui a perspectiva das crianças. O objetivo é explorar o bullying como um fenômeno social complexo de grupo que permite enfocar o processo de bullying criando, assim, uma oportunidade para melhorar o conhecimento das ações e perspectivas inter e intra-conectadas. Este artigo tem a intenção de contribuir para uma discussão sobre a ampliação da conceptualização do bullying

Approximate probabilistic verification of hybrid systems

Hybrid systems whose mode dynamics are governed by non-linear ordinary differential equations (ODEs) are often a natural model for biological processes. However such models are difficult to analyze. To address this, we develop a probabilistic analysis method by approximating the mode transitions as stochastic events. We assume that the probability of making a mode transition is proportional to the measure of the set of pairs of time points and value states at which the mode transition is enabled. To ensure a sound mathematical basis, we impose a natural continuity property on the non-linear ODEs. We also assume that the states of the system are observed at discrete time points but that the mode transitions may take place at any time between two successive discrete time points. This leads to a discrete time Markov chain as a probabilistic approximation of the hybrid system. We then show that for BLTL (bounded linear time temporal logic) specifications the hybrid system meets a specification iff its Markov chain approximation meets the same specification with probability $1$. Based on this, we formulate a sequential hypothesis testing procedure for verifying -approximately- that the Markov chain meets a BLTL specification with high probability. Our case studies on cardiac cell dynamics and the circadian rhythm indicate that our scheme can be applied in a number of realistic settings

VEGAS: A VST Early-type GAlaxy Survey. II. Photometric study of giant ellipticals and their stellar halos

Observations of diffuse starlight in the outskirts of galaxies are thought to be a fundamental source of constraints on the cosmological context of galaxy assembly in the $\Lambda$CDM model. Such observations are not trivial because of the extreme faintness of such regions. In this work, we investigate the photometric properties of six massive early type galaxies (ETGs) in the VEGAS sample (NGC 1399, NGC 3923, NGC 4365, NGC 4472, NGC 5044, and NGC 5846) out to extremely low surface brightness levels, with the goal of characterizing the global structure of their light profiles for comparison to state-of-the-art galaxy formation models. We carry out deep and detailed photometric mapping of our ETG sample taking advantage of deep imaging with VST/OmegaCAM in the g and i bands. By fitting the light profiles, and comparing the results to simulations of elliptical galaxy assembly, we identify signatures of a transition between "relaxed" and "unrelaxed" accreted components and can constrain the balance between in situ and accreted stars. The very good agreement of our results with predictions from theoretical simulations demonstrates that the full VEGAS sample of $\sim 100$ ETGs will allow us to use the distribution of diffuse light as a robust statistical probe of the hierarchical assembly of massive galaxies.Comment: Accepted for publication in Astronomy & Astrophysic