Diffuse Gamma Rays: Galactic and Extragalactic Diffuse Emission

"Diffuse" gamma rays consist of several components: truly diffuse emission from the interstellar medium, the extragalactic background, whose origin is not firmly established yet, and the contribution from unresolved and faint Galactic point sources. One approach to unravel these components is to study the diffuse emission from the interstellar medium, which traces the interactions of high energy particles with interstellar gas and radiation fields. Because of its origin such emission is potentially able to reveal much about the sources and propagation of cosmic rays. The extragalactic background, if reliably determined, can be used in cosmological and blazar studies. Studying the derived "average" spectrum of faint Galactic sources may be able to give a clue to the nature of the emitting objects.Comment: 32 pages, 28 figures, kapproc.cls. Chapter to the book "Cosmic Gamma-Ray Sources," to be published by Kluwer ASSL Series, Edited by K. S. Cheng and G. E. Romero. More details can be found at http://www.gamma.mpe-garching.mpg.de/~aws/aws.htm

Subjective utility moderates bidirectional effects of conflicting motivations on pain perception

Minimizing pain and maximizing pleasure are conflicting motivations when pain and reward co-occur. Decisions to prioritize reward consumption or pain avoidance are assumed to lead to pain inhibition or facilitation, respectively. Such decisions are a function of the subjective utility of the stimuli involved, i.e. the relative value assigned to the stimuli to compare the potential outcomes of a decision. To test perceptual pain modulation by varying degrees of motivational conflicts and the role of subjective utility, we implemented a task in which healthy volunteers had to decide between accepting a reward at the cost of receiving a nociceptive electrocutaneous stimulus or rejecting both. Subjective utility of the stimuli was assessed by a matching task between the stimuli. Accepting reward coupled to a nociceptive stimulus resulted in decreased perceived intensity, while rejecting the reward to avoid pain resulted in increased perceived intensity, but in both cases only if a high motivational conflict was present. Subjective utility of the stimuli involved moderated these bidirectional perceptual effects: the more a person valued money over pain, the more perceived intensity increased or decreased. These findings demonstrate pain modulation when pain and reward are simultaneously present and highlight the importance of subjective utility for such modulation

Assessing the psychometric and ecometric properties of neighborhood scales using adolescent survey data from urban and rural Scotland

This work was supported by NHS Health Scotland and the University of St Andrews.Background:  Despite the well-established need for specific measurement instruments to examine the relationship between neighborhood conditions and adolescent well-being outcomes, few studies have developed scales to measure features of the neighborhoods in which adolescents reside. Moreover, measures of neighborhood features may be operationalised differently by adolescents living in different levels of urban/rurality. This has not been addressed in previous studies. The objectives of this study were to: 1) establish instruments to measure adolescent neighborhood features at both the individual and neighborhood level, 2) assess their psychometric and ecometric properties, 3) test for invariance by urban/rurality, and 4) generate neighborhood level scores for use in further analysis. Methods:  Data were from the Scottish 2010 Health Behaviour in School-aged Children Survey, which included an over-sample of rural adolescents. The survey responses of interest came from questions designed to capture different facets of the local area in which each respondent resided. Intermediate data zones were used as proxies for neighborhoods. Internal consistency was evaluated by Cronbach’s alpha. Invariance was examined using confirmatory factor analysis. Multilevel models were used to estimate ecometric properties and generate neighborhood scores. Results:  Two constructs labeled neighborhood social cohesion and neighborhood disorder were identified. Adjustment was made to the originally specified model to improve model fit and measures of invariance. At the individual level, reliability was .760 for social cohesion and .765 for disorder, and between .524 and .571 for both constructs at the neighborhood level. Individuals in rural areas experienced greater neighborhood social cohesion and lower levels of neighborhood disorder compared with those in urban areas. Conclusions:  The scales are appropriate for measuring neighborhood characteristics experienced by adolescents across urban and rural Scotland, and can be used in future studies of neighborhoods and health. However, trade-offs between neighborhood sample size and reliability must be considered.Publisher PDFPeer reviewe

Morphine activation of mu opioid receptors causes disinhibition of neurons in the ventral tegmental area mediated by β-arrestin2 and c-Src

Abstract The tyrosine kinase, c-Src, participates in mu opioid receptor (MOP) mediated inhibition in sensory neurons in which β-arrestin2 (β-arr2) is implicated in its recruitment. Mice lacking β-arr2 exhibit increased sensitivity to morphine reinforcement; however, whether β-arr2 and/or c-Src participate in the actions of opioids in neurons within the reward pathway is unknown. It is also unclear whether morphine acts exclusively through MOPs, or involves delta opioid receptors (DOPs). We examined the involvement of MOPs, DOPs, β-arr2 and c-Src in the inhibition by morphine of GABAergic inhibitory postsynaptic currents (IPSCs) recorded from neurons in the mouse ventral tegmental area. Morphine inhibited spontaneous IPSC frequency, mainly through MOPs, with only a negligible effect remaining in MOP−/− neurons. However, a reduction in the inhibition by morphine for DOP−/− c.f. WT neurons and a DPDPE-induced decrease of IPSC frequency revealed a role for DOPs. The application of the c-Src inhibitor, PP2, to WT neurons also reduced inhibition by morphine, while the inactive PP3, and the MEK inhibitor, SL327, had no effect. Inhibition of IPSC frequency by morphine was also reduced in β-arr2−/− neurons in which PP2 caused no further reduction. These data suggest that inhibition of IPSCs by morphine involves a β-arr2/c-Src mediated mechanism

Strong interface-induced spin-orbit coupling in graphene on WS2

Interfacial interactions allow the electronic properties of graphene to be modified, as recently demonstrated by the appearance of satellite Dirac cones in the band structure of graphene on hexagonal boron nitride (hBN) substrates. Ongoing research strives to explore interfacial interactions in a broader class of materials in order to engineer targeted electronic properties. Here we show that at an interface with a tungsten disulfide (WS2) substrate, the strength of the spin-orbit interaction (SOI) in graphene is very strongly enhanced. The induced SOI leads to a pronounced low-temperature weak anti-localization (WAL) effect, from which we determine the spin-relaxation time. We find that spin-relaxation time in graphene is two-to-three orders of magnitude smaller on WS2 than on SiO2 or hBN, and that it is comparable to the intervalley scattering time. To interpret our findings we have performed first-principle electronic structure calculations, which both confirm that carriers in graphene-on-WS2 experience a strong SOI and allow us to extract a spin-dependent low-energy effective Hamiltonian. Our analysis further shows that the use of WS2 substrates opens a possible new route to access topological states of matter in graphene-based systems.Comment: Originally submitted version in compliance with editorial guidelines. Final version with expanded discussion of the relation between theory and experiments to be published in Nature Communication

Formation of regulatory modules by local sequence duplication

Turnover of regulatory sequence and function is an important part of molecular evolution. But what are the modes of sequence evolution leading to rapid formation and loss of regulatory sites? Here, we show that a large fraction of neighboring transcription factor binding sites in the fly genome have formed from a common sequence origin by local duplications. This mode of evolution is found to produce regulatory information: duplications can seed new sites in the neighborhood of existing sites. Duplicate seeds evolve subsequently by point mutations, often towards binding a different factor than their ancestral neighbor sites. These results are based on a statistical analysis of 346 cis-regulatory modules in the Drosophila melanogaster genome, and a comparison set of intergenic regulatory sequence in Saccharomyces cerevisiae. In fly regulatory modules, pairs of binding sites show significantly enhanced sequence similarity up to distances of about 50 bp. We analyze these data in terms of an evolutionary model with two distinct modes of site formation: (i) evolution from independent sequence origin and (ii) divergent evolution following duplication of a common ancestor sequence. Our results suggest that pervasive formation of binding sites by local sequence duplications distinguishes the complex regulatory architecture of higher eukaryotes from the simpler architecture of unicellular organisms

Purinergic signalling links mechanical breath profile and alveolar mechanics with the pro-inflammatory innate immune response causing ventilation-induced lung injury

Severe pulmonary infection or vigorous cyclic deformation of the alveolar epithelial type I (AT I) cells by mechanical ventilation leads to massive extracellular ATP release. High levels of extracellular ATP saturate the ATP hydrolysis enzymes CD39 and CD73 resulting in persistent high ATP levels despite the conversion to adenosine. Above a certain level, extracellular ATP molecules act as danger-associated molecular patterns (DAMPs) and activate the pro-inflammatory response of the innate immunity through purinergic receptors on the surface of the immune cells. This results in lung tissue inflammation, capillary leakage, interstitial and alveolar oedema and lung injury reducing the production of surfactant by the damaged AT II cells and deactivating the surfactant function by the concomitant extravasated serum proteins through capillary leakage followed by a substantial increase in alveolar surface tension and alveolar collapse. The resulting inhomogeneous ventilation of the lungs is an important mechanism in the development of ventilation-induced lung injury. The high levels of extracellular ATP and the upregulation of ecto-enzymes and soluble enzymes that hydrolyse ATP to adenosine (CD39 and CD73) increase the extracellular adenosine levels that inhibit the innate and adaptive immune responses rendering the host susceptible to infection by invading microorganisms. Moreover, high levels of extracellular adenosine increase the expression, the production and the activation of pro-fibrotic proteins (such as TGF-β, α-SMA, etc.) followed by the establishment of lung fibrosis

Survey context and question wording affects self reported annoyance due to road traffic noise: a comparison between two cross-sectional studies

<p>Abstract</p> <p>Background</p> <p>Surveys are a common way to measure annoyance due to road traffic noise, but the method has some draw-backs. Survey context, question wording and answer alternatives could affect participation and answers and could have implications when comparing studies and/or performing pooled analyses. The aim of this study was to investigate the difference in annoyance reporting due to road traffic noise in two types of surveys of which one was introduced broadly and the other with the clearly stated aim of investigating noise and health.</p> <p>Methods</p> <p>Data was collected from two surveys carried out in the municipality of Malmö, southern Sweden in 2007 and 2008 (n = 2612 and n = 3810). The first survey stated an aim of investigating residential environmental exposure, especially noise and health. The second survey was a broad public health survey stating a broader aim. The two surveys had comparable questions regarding noise annoyance, although one used a 5-point scale and the other a 4-point scale. We used geographic information systems (GIS) to assess the average road and railway noise (L_Aeq,24h) at the participants' residential address. Logistic regression was used to calculate odds ratios for annoyance in relation to noise exposure.</p> <p>Results</p> <p>Annoyance at least once a week due to road traffic noise was significantly more prevalent in the survey investigating environment and health compared to the public health survey at levels > 45 dB(A), but not at lower exposure levels. However no differences in annoyance were found when comparing the extreme alternatives "never" and "every day". In the study investigating environment and health, "Noise sensitive" persons were more likely to readily respond to the survey and were more annoyed by road traffic noise compared to the other participants in that survey.</p> <p>Conclusions</p> <p>The differences in annoyance reporting between the two surveys were mainly due to different scales, suggesting that extreme alternatives are to prefer before dichotomization when comparing results between the two. Although some findings suggested that noise-sensitive individuals were more likely to respond to the survey investigating noise and health, we could not find convincing evidence that contextual differences affected either answers or participation.</p

A systematic review of tests of empathy in medicine

Abstract Background Empathy is frequently cited as an important attribute in physicians and some groups have expressed a desire to measure empathy either at selection for medical school or during medical (or postgraduate) training. In order to do this, a reliable and valid test of empathy is required. The purpose of this systematic review is to determine the reliability and validity of existing tests for the assessment of medical empathy. Methods A systematic review of research papers relating to the reliability and validity of tests of empathy in medical students and doctors. Journal databases (Medline, EMBASE, and PsycINFO) were searched for English-language articles relating to the assessment of empathy and related constructs in applicants to medical school, medical students, and doctors. Results From 1147 citations, we identified 50 relevant papers describing 36 different instruments of empathy measurement. As some papers assessed more than one instrument, there were 59 instrument assessments. 20 of these involved only medical students, 30 involved only practising clinicians, and three involved only medical school applicants. Four assessments involved both medical students and practising clinicians, and two studies involved both medical school applicants and students. Eight instruments demonstrated evidence of reliability, internal consistency, and validity. Of these, six were self-rated measures, one was a patient-rated measure, and one was an observer-rated measure. Conclusion A number of empathy measures available have been psychometrically assessed for research use among medical students and practising medical doctors. No empathy measures were found with sufficient evidence of predictive validity for use as selection measures for medical school. However, measures with a sufficient evidential base to support their use as tools for investigating the role of empathy in medical training and clinical care are available.</p

Legionella Metaeffector Exploits Host Proteasome to Temporally Regulate Cognate Effector

Pathogen-associated secretion systems translocate numerous effector proteins into eukaryotic host cells to coordinate cellular processes important for infection. Spatiotemporal regulation is therefore important for modulating distinct activities of effectors at different stages of infection. Here we provide the first evidence of “metaeffector,” a designation for an effector protein that regulates the function of another effector within the host cell. Legionella LubX protein functions as an E3 ubiquitin ligase that hijacks the host proteasome to specifically target the bacterial effector protein SidH for degradation. Delayed delivery of LubX to the host cytoplasm leads to the shutdown of SidH within the host cells at later stages of infection. This demonstrates a sophisticated level of coevolution between eukaryotic cells and L. pneumophila involving an effector that functions as a key regulator to temporally coordinate the function of a cognate effector protein