223 research outputs found

    Experimental Investigation of the Nature of the Knee in the Primary Cosmic Ray Energy Spectrum with the GAMMA experiment

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    We present preliminary results obtained by a novel difference method for the study of the nature of the knee in the energy spectrum of the primary cosmic radiation. We have applied this method to data from the GAMMA experiment in Armenia. The analysis provides evidence for the possible existence of a nearby source of primary cosmic rays in the Southern hemisphere.Comment: 17 pages, 5 figure

    Positivity in younger and in older age: Associations with future time perspective and socioemotional functioning

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    Aging has been associated with a motivational shift to positive over negative information (i.e., positivity effect), which is often explained by a limited future time perspective (FTP) within the framework of socioemotional selectivity theory (SST). However, whether a limited FTP functions similarly in younger and older adults, and whether inter-individual differences in socioemotional functioning are similarly associated with preference for positive information (i.e., positivity) is still not clear. We investigated younger (20–35 years, N = 73) and older (60–75 years, N = 56) adults’ gaze preferences on pairs of happy, angry, sad, and neutral faces using an eye-tracking system. We additionally assessed several parameters potentially underlying inter-individual differences in emotion processing such as FTP, stress, cognitive functioning, social support, emotion regulation, and well-being. While we found no age-related differences in positivity when the entire trial duration was considered, older adults showed longer fixations on the more positive face in later stages of processing (i.e., positivity shifts). This allocation of resources toward more positive stimuli might serve an emotion regulatory purpose and seems consistent with the SST. However, our findings suggest that age moderates the relationship between FTP and positivity shifts, such that the relationship between FTP and positivity preferences was negative in older, and positive in younger adults, potentially stemming from an age-related differential meaning of the FTP construct across age. Furthermore, our exploratory analyses showed that along with the age and FTP interaction, lower levels of worry also played a significant role in positivity shifts. We conclude that positivity effects cannot be solely explained by aging, or the associated reduced FTP per se, but is rather determined by a complex interplay of psychosocial and emotional features

    Accurate measurement of the pulse wave delay with imaging photoplethysmography

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    © 2016 Optical Society of America.Assessment of the cardiovascular parameters using noncontact video-based or imaging photoplethysmography (IPPG) is usually considered as inaccurate because of strong influence of motion artefacts. To optimize this technique we performed a simultaneous recording of electrocardiogram and video frames of the face for 36 healthy volunteers. We found that signal disturbances originate mainly from the stochastically enhanced dichroic notch caused by endogenous cardiovascular mechanisms, with smaller contribution of the motion artefacts. Our properly designed algorithm allowed us to increase accuracy of the pulse-transit-time measurement and visualize propagation of the pulse wave in the facial region. Thus, the accurate measurement of the pulse wave parameters with this technique suggests a sensitive approach to assess local regulation of microcirculation in various physiological and pathological states

    Synaptic abnormalities in the infralimbic cortex of a model of congenital depression

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    Multiple lines of evidence suggest that disturbances in excitatory transmission contribute to depression. Whether these defects involve the number, size, or composition of glutamatergic contacts is unclear. This study used recently introduced procedures for fluorescence deconvolution tomography in a well-studied rat model of congenital depression to characterize excitatory synapses in layer I of infralimbic cortex, a region involved in mood disorders, and of primary somatosensory cortex. Three groups were studied: (1) rats bred for learned helplessness (cLH); (2) rats resistant to learned helplessness (cNLH); and (3) control Sprague Dawley rats. In fields within infralimbic cortex, cLH rats had the same numerical density of synapses, immunolabeled for either the postsynaptic density (PSD) marker PSD95 or the presynaptic protein synaptophysin, as controls. However, PSD95 immunolabeling intensities were substantially lower in cLH rats, as were numerical densities of synapse-sized clusters of the AMPA receptor subunit GluA1. Similar but less pronounced differences (comparable numerical densities but reduced immunolabeling intensity for PSD95) were found in the somatosensory cortex. In contrast, non-helpless rats had 25% more PSDs than either cLH or control rats without any increase in synaptophysin-labeled terminal frequency. Compared with controls, both cLH and cNLH rats had fewer GABAergic contacts. These results indicate that congenital tendencies that increase or decrease depression-like behavior differentially affect excitatory synapses

    Ionization by bulk heating of electrons in capacitive radio frequency atmospheric pressure microplasmas

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    Electron heating and ionization dynamics in capacitively coupled radio frequency (RF) atmospheric pressure microplasmas operated in helium are investigated by Particle in Cell simulations and semi-analytical modeling. A strong heating of electrons and ionization in the plasma bulk due to high bulk electric fields are observed at distinct times within the RF period. Based on the model the electric field is identified to be a drift field caused by a low electrical conductivity due to the high electron-neutral collision frequency at atmospheric pressure. Thus, the ionization is mainly caused by ohmic heating in this "Omega-mode". The phase of strongest bulk electric field and ionization is affected by the driving voltage amplitude. At high amplitudes, the plasma density is high, so that the sheath impedance is comparable to the bulk resistance. Thus, voltage and current are about 45{\deg} out of phase and maximum ionization is observed during sheath expansion with local maxima at the sheath edges. At low driving voltages, the plasma density is low and the discharge becomes more resistive resulting in a smaller phase shift of about 4{\deg}. Thus, maximum ionization occurs later within the RF period with a maximum in the discharge center. Significant analogies to electronegative low pressure macroscopic discharges operated in the Drift-Ambipolar mode are found, where similar mechanisms induced by a high electronegativity instead of a high collision frequency have been identified

    Novel capsaicin-induced parameters of microcirculation in migraine patients revealed by imaging photoplethysmography

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    © 2018, The Author(s). Background: The non-invasive biomarkers of migraine can help to develop the personalized medication of this disorder. In testing of the antimigraine drugs the capsaicin-induced skin redness with activated TRPV1 receptors in sensory neurons associated with the release of the migraine mediator CGRP has already been widely used. Methods: Fourteen migraine patients (mean age 34.6 ± 10.2 years) and 14 healthy volunteers (mean age 29.9 ± 9.7 years) participated in the experiment. A new arrangement of imaging photoplethysmography recently developed by us was used here to discover novel sensitive parameters of dermal blood flow during capsaicin applications in migraine patients. Results: Blood pulsation amplitude (BPA) observed as optical-intensity waveform varying synchronously with heartbeat was used for detailed exploration of microcirculatory perfusion induced by capsicum patch application. The BPA signals, once having appeared after certain latent period, were progressively rising until being saturated. Capsaicin-induced high BPA areas were distributed unevenly under the patch, forming “hot spots.” Interestingly the hot spots were much more variable in migraine patients than in the control group. In contrast to BPA, a slow component of waveforms related to the skin redness changed significantly less than BPA highlighting the latter parameter as the potential sensitive biomarker of capsaicin-induced activation of the blood flow. Thus, in migraine patients, there is a non-uniform (both in space and in time) reaction to capsaicin, resulting in highly variable openings of skin capillaries. Conclusion: BPA dynamics measured by imaging photoplethysmography could serve as a novel sensitive non-invasive biomarker of migraine-associated changes in microcirculation

    Halal dating: changing relationship attitudes and experiences among young British Muslims

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    Young Muslims in the UK are making space to gain greater control over their personal lives through the diction of ‘halal’ and ‘haram’ when reflecting on and negotiating personal relationships. This article explores the significance of ‘halal dating’ within the lived experiences and sexual relationships of young British Muslims. It draws upon 56 in-depth interviews conducted with young (16–30 years) British Muslims of Pakistani heritage. This research shows that, contrary to popular stereotype and widespread expectations, many young British Muslims do date, or have dated. By entertaining the idea that certain forms of dating may be halal, these young Muslims are finding and claiming agency to make relationship choices of their own

    Armenia and Belarus: caught between the EU's and Russia's conditionalities?

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    This article looks into Armenia's and Belarus’ engagement with the European Union's (EU) and Russia's conditionalities, the two EU Eastern Partnership (EaP) countries that are also members of the Russia-led Eurasian Economic Union (EAEU). While paying attention to political, economic (including energy and technical) as well as security dimensions of the EU's and Russia's approaches, as proposed in the present special section, the article demonstrates that the conditionalities extended by the EU and Russia to the two countries in question have differed. In their turn, Armenia and Belarus have reacted differently to Russia's and the EU's conditionalities. Against the backdrop of the changing significance ascribed to both the EU's and Russia's policies towards their common neighbourhood since the 1990s, the present contribution identifies and analyses factors that account for the diverging positions of Armenia and Belarus, including the type of regime, the geopolitical considerations, the stakes in the economic and energy spheres and the predisposition to integration. The article shows that in the resulting complex context, Armenia and Belarus have been able to influence the shape and content of the EU's and Russia's conditionalities, although in a different way and to a different extent.Ministry of Education and Science (UID/CPO/ 00758/2013
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