283 research outputs found

    The BTZ black hole with a time-dependent boundary

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    The non-rotating BTZ solution is expressed in terms of coordinates that allow for an arbitrary time-dependent scale factor in the boundary metric. We provide explicit expressions for the coordinate transformation that generates this form of the metric, and determine the regions of the complete Penrose diagram that are convered by our parametrization. This construction is utilized in order to compute the stress-energy tensor of the dual CFT on a time-dependent background. We study in detail the expansion of radial null geodesic congruences in the BTZ background for various forms of the scale factor of the boundary metric. We also discuss the relevance of our construction for the holographic calculation of the entanglement entropy of the dual CFT on time-dependent backgrounds.Comment: 14 pages, 13 figures, title changed in journal, conformal diagrams added, references added, final version to appear in Classical and Quantum Gravit

    Entanglement Entropy from a Holographic Viewpoint

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    The entanglement entropy has been historically studied by many authors in order to obtain quantum mechanical interpretations of the gravitational entropy. The discovery of AdS/CFT correspondence leads to the idea of holographic entanglement entropy, which is a clear solution to this important problem in gravity. In this article, we would like to give a quick survey of recent progresses on the holographic entanglement entropy. We focus on its gravitational aspects, so that it is comprehensible to those who are familiar with general relativity and basics of quantum field theory.Comment: Latex, 30 pages, invited review for Classical and Quantum Gravity, minor correction

    The Impact Of Consumer Attitudes About Bioengineering On Purchase Behavior Intentions: Moderating Effects Of Innate Consumer Innovativeness And Anxiety

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    Biotechnology is anticipated to be the next generation of innovations and is predicted to surpass the IT revolution in terms of economic prosperity (Darby and Zucher, 2003).  But available behavioral and social research relating to biotechnology is at its infant stage.  Most studies are qualitative in nature (i.e., focus groups) and are limited to public policy issues such as awareness, knowledge, and perception of risks (Bredahl, 1999; Frewer et al., 1997; Frewer, Howard, and Shepherd, 1997). According to Bredahl, 2001, few research projects have yet to determine how consumer attitudes can be expected to influence subsequent purchase behavior intentions with genetically modified products. As the U.S. Food and Drug Administration (FDA) continues to approve more and more inventions of biotechnology (i.e., foods such as genetically engineered potatoes and rice; industrial plastic from genetically modified organisms; and life saving pharmaceuticals for diseases such as cancer, HIV, and Alzheimer’s) there is a need for research that investigates how consumer attitudes about genetically modified products influence their purchase intentions and subsequent purchase behavior.  The primary purpose of this research is to investigate how consumer attitudes about bioengineering influence their purchase behavior intentions. Second, the influence of two personal variables innate consumer innovativeness and general anxiety about bioengineering as they relate to purchase behavior intentions will be investigated.  Finally, the study also makes an attempt to determine if the relationship between attitude and behavior intentions is moderated by the two personal variables innate consumer innovativeness and general anxiety about bioengineering.  Personal variables such as these can reasonably be expected to have a differential impact on the relationship between attitude about bioengineering and purchase behavior intentions.  That is, the strength of the relationship between attitude and purchase behavior intentions is likely to be stronger for consumers that are innovative and less anxious about bioengineering than others.  The study results have implications for both researchers and promoters of bioengineering. For researchers, it should be noted that an extensive literature search was unable to find any empirical research to date that have investigated the moderating effects on the relationship between attitude about bioengineering and purchase behavior intentions.  For practitioners, the study will aid biotechnology firms in their efforts in building a more positive attitude about biotechnology in general and to identify the profile of consumers that are more likely to purchase and use products of this technology

    Can adas distract driver’s attention? An rgb-d camera and deep learning-based analysis

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    Driver inattention is the primary cause of vehicle accidents; hence, manufacturers have introduced systems to support the driver and improve safety; nonetheless, advanced driver assistance systems (ADAS) must be properly designed not to become a potential source of distraction for the driver due to the provided feedback. In the present study, an experiment involving auditory and haptic ADAS has been conducted involving 11 participants, whose attention has been monitored during their driving experience. An RGB-D camera has been used to acquire the drivers’ face data. Subsequently, these images have been analyzed using a deep learning-based approach, i.e., a convolutional neural network (CNN) specifically trained to perform facial expression recognition (FER). Analyses to assess possible relationships between these results and both ADAS activations and event occurrences, i.e., accidents, have been carried out. A correlation between attention and accidents emerged, whilst facial expressions and ADAS activations resulted to be not correlated, thus no evidence that the designed ADAS are a possible source of distraction has been found. In addition to the experimental results, the proposed approach has proved to be an effective tool to monitor the driver through the usage of non-invasive techniques

    Angular reconstruction of high energy air showers using the radio signal spectrum

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    The Hellenic Open University extensive air shower array (also known as Astroneu array) is a small scale hybrid detection system operating in an area with high levels of electromagnetic noise from anthropogenic activity. In the present study we report the latest results of the data analysis concerning the estimation of the shower direction using the spectrum of the RF system. In a recent layout of the array, 4 RF antennas were operating receiving a common trigger from an autonomous detection station of 3 particle detectors. The directions estimated with the RF system are in very good agreement with the corresponding estimations using the particle detectors demonstrating that a single antenna has the potential for reconstructing the shower axis angular direction

    Understanding the Interplay Among Regulatory Self-Efficacy, Moral Disengagement, and Academic Cheating Behaviour During Vocational Education: A Three-Wave Study

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    The literature has suggested that to understand the diffusion of unethical conduct in the workplace, it is important to investigate the underlying processes sustaining engagement in misbehaviour and to study what occurs during vocational education. Drawing on social-cognitive theory, in this study, we longitudinally examined the role of two opposite dimensions of the self-regulatory moral system, regulatory self-efficacy and moral disengagement, in influencing academic cheating behaviour. In addition, in line with the theories highlighting the bidirectional relationship between cognitive processes and behaviour, we aimed to also examine the reciprocal influence of behaviour on these dimensions over time. Overall, no previous studies have examined the longitudinal interplay between these variables. The sample included 866 (62.8% female) nursing students who were assessed three times annually from the beginning of their vocational education. The findings from a cross-lagged model confirmed that regulatory self-efficacy and moral disengagement have opposite influences on cheating behaviour, that regulatory self-efficacy negatively influences not only the engagement in misconduct but also the justification mechanisms that allow the divorce between moral standards and action, and that moral disengagement and cheating behaviour reciprocally support each other over time. Specifically, not only did moral disengagement influence cheating behaviour even when controlling for its prior levels, but also cheating behaviour affected moral disengagement one year later, controlling for its prior levels. These findings suggest that recourse to wrongdoing could gradually lead to further normalising this kind of behaviour and morally desensitising individuals to misconduct

    A primary electron beam facility at CERN -- eSPS Conceptual design report

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    The design of a primary electron beam facility at CERN is described. The study has been carried out within the framework of the wider Physics Beyond Colliders study. It re-enables the Super Proton Synchrotron (SPS) as an electron accelerator, and leverages the development invested in Compact Linear Collider (CLIC) technology for its injector and as an accelerator research and development infrastructure. The facility would be relevant for several of the key priorities in the 2020 update of the European Strategy for Particle Physics, such as an electron-positron Higgs factory, accelerator R\&D, dark sector physics, and neutrino physics. In addition, it could serve experiments in nuclear physics. The electron beam delivered by this facility would provide access to light dark matter production significantly beyond the targets predicted by a thermal dark matter origin, and for natures of dark matter particles that are not accessible by direct detection experiments. It would also enable electro-nuclear measurements crucial for precise modelling the energy dependence of neutrino-nucleus interactions, which is needed to precisely measure neutrino oscillations as a function of energy. The implementation of the facility is the natural next step in the development of X-band high-gradient acceleration technology, a key technology for compact and cost-effective electron/positron linacs. It would also become the only facility with multi-GeV drive bunches and truly independent electron witness bunches for plasma wakefield acceleration. A second phase capable to deliver positron witness bunches would make it a complete facility for plasma wakefield collider studies. [...

    Expression Patterns of Genes Involved in Sugar Metabolism and Accumulation during Apple Fruit Development

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    Both sorbitol and sucrose are imported into apple fruit from leaves. The metabolism of sorbitol and sucrose fuels fruit growth and development, and accumulation of sugars in fruit is central to the edible quality of apple. However, our understanding of the mechanisms controlling sugar metabolism and accumulation in apple remains quite limited. We identified members of various gene families encoding key enzymes or transporters involved in sugar metabolism and accumulation in apple fruit using homology searches and comparison of their expression patterns in different tissues, and analyzed the relationship of their transcripts with enzyme activities and sugar accumulation during fruit development. At the early stage of fruit development, the transcript levels of sorbitol dehydrogenase, cell wall invertase, neutral invertase, sucrose synthase, fructokinase and hexokinase are high, and the resulting high enzyme activities are responsible for the rapid utilization of the imported sorbitol and sucrose for fruit growth, with low levels of sugar accumulation. As the fruit continues to grow due to cell expansion, the transcript levels and activities of these enzymes are down-regulated, with concomitant accumulation of fructose and elevated transcript levels of tonoplast monosaccharide transporters (TMTs), MdTMT1 and MdTMT2; the excess carbon is converted into starch. At the late stage of fruit development, sucrose accumulation is enhanced, consistent with the elevated expression of sucrose-phosphate synthase (SPS), MdSPS5 and MdSPS6, and an increase in its total activity. Our data indicate that sugar metabolism and accumulation in apple fruit is developmentally regulated. This represents a comprehensive analysis of the genes involved in sugar metabolism and accumulation in apple, which will serve as a platform for further studies on the functions of these genes and subsequent manipulation of sugar metabolism and fruit quality traits related to carbohydrates

    Conserved Genes Act as Modifiers of Invertebrate SMN Loss of Function Defects

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    Spinal Muscular Atrophy (SMA) is caused by diminished function of the Survival of Motor Neuron (SMN) protein, but the molecular pathways critical for SMA pathology remain elusive. We have used genetic approaches in invertebrate models to identify conserved SMN loss of function modifier genes. Drosophila melanogaster and Caenorhabditis elegans each have a single gene encoding a protein orthologous to human SMN; diminished function of these invertebrate genes causes lethality and neuromuscular defects. To find genes that modulate SMN function defects across species, two approaches were used. First, a genome-wide RNAi screen for C. elegans SMN modifier genes was undertaken, yielding four genes. Second, we tested the conservation of modifier gene function across species; genes identified in one invertebrate model were tested for function in the other invertebrate model. Drosophila orthologs of two genes, which were identified originally in C. elegans, modified Drosophila SMN loss of function defects. C. elegans orthologs of twelve genes, which were originally identified in a previous Drosophila screen, modified C. elegans SMN loss of function defects. Bioinformatic analysis of the conserved, cross-species, modifier genes suggests that conserved cellular pathways, specifically endocytosis and mRNA regulation, act as critical genetic modifiers of SMN loss of function defects across species
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