Roton dipole moment

The roton excitation in the superfluid He-4 does not possess a stationary dipole moment. However, a roton has an instantaneous dipole moment, such that at any given moment one can find it in the state either with positive or with negative dipole moment projection on its momentum direction. The instantaneous value of electric dipole moment of roton excitation is evaluated. The result is in reasonable agreement with recent experimental observation of the splitting of microwave resonance absorption line at roton frequency under external electric field.Comment: 5 page

Micro-Ramps for External Compression Low-Boom Inlets

The application of vortex generators for flow control in an external compression, axisymmetric, low-boom concept inlet was investigated using RANS simulations with three-dimensional (3-D), structured, chimera (overset) grids and the WIND-US code. The low-boom inlet design is based on previous scale model 1- by 1-ft wind tunnel tests and features a zero-angle cowl and relaxed isentropic compression centerbody spike, resulting in defocused oblique shocks and a weak terminating normal shock. Validation of the methodology was first performed for micro-ramps in supersonic flow on a flat plate with and without oblique shocks. For the inlet configuration, simulations with several types of vortex generators were conducted for positions both upstream and downstream of the terminating normal shock. The performance parameters included incompressible axisymmetric shape factor, separation area, inlet pressure recovery, and massflow ratio. The design of experiments (DOE) methodology was used to select device size and location, analyze the resulting data, and determine the optimal choice of device geometry. The optimum upstream configuration was found to substantially reduce the post-shock separation area but did not significantly impact recovery at the aerodynamic interface plane (AIP). Downstream device placement allowed for fuller boundary layer velocity profiles and reduced distortion. This resulted in an improved pressure recovery and massflow ratio at the AIP compared to the baseline solid-wall configuration

A search for disordered (glassy) phase in solid 3He deformed in situ

A disordered (glassy) state has been searched in solid 3He deformed in the course of experiment employing precise measurements of pressure. The analysis of the temperature dependence of the crystal pressure measured at a constant volume shows that the main contribution to the pressure is made by the phonon subsystem, the influence of the disordered phase being very weak. Annealing of the deformed crystal does not affect this state. The results obtained differ greatly from the corresponding data for solid 4He measured in the region of supersolid effects where a pressure excessive in comparison to the phonon one was registered. The excess pressure had a quadratic dependence on temperature, which is typical of a disordered system. Absence of the excess pressure in solid 3He is unclear yet, some speculative interpretations are suggested.Comment: 9 pages, 4 figure

Этиология криптогенного инсульта

Ischemic stroke is a heterogeneous syndrome with a plurality of potential etiological factors. The routine diagnosis does not always allow the cause of acute cerebrovascular accident to be found, in such cases we talk about cryptogenic ischemic stroke, which incidence is 20-40%. The category of patients with cryptogenic stroke was first characterized and assigned to a separate group in the database of the National Institute of Neurological Diseases and Stroke in the USA, and later in the TOAST study. The diagnosis of cryptogenic stroke is usually based on the exclusion of well-known causes of acute cerebrovascular accidents, such as atherosclerosis, cardiac arrhythmias, arterial hypertension. Due to the considerable variability of concepts for cryptogenic stroke, the term ESUS (Embolic Stroke of Undetermined Source) appeared in 2014 and formulated criteria which accurately characterized these patients: non-lacunar cerebral infarction by CT and/or MRI, no atherosclerotic lesion stenosing a stroke-associated artery of more than 50%, no sources of high-risk cardioembolism, no other causes of stroke such as dissection of the artery supplying the area of infarction in the brain, migraine, arteritis. Among the potential causes and sources of cerebral embolism in patients with cryptogenic stroke are heart, veins of lower extremities and pelvis, nonstenosing atherosclerosis of brachiocephalic artery, atheroma of aortic arch, paradoxical embolism non-atherosclerotic vasculopathy, monogenic diseases, hypercoagulable states, and others. We should note that there is a lot of studies on the possible causes of cryptogenic stroke in the available literature, but no common approach to classification of etiologic factors and examination algorythms were developed. The high incidence of cryptogenic stroke, the significant heterogeneity of its etiopathogenetic mechanisms and the need for differentiated approaches to the secondary prevention of this type of acute cerebrovascular accident determine the relevance of further studies in this field.Ишемический инсульт является гетерогенным синдромом с множеством потенциально возможных этиологических факторов. Рутинная диагностика не всегда позволяет установить причину острого нарушения мозгового кровообращения (ОНМК), в таких случаях принято говорить о криптогенном ишемическом инсульте, частота которого составляет 20–40%. Категория пациентов с криптогенным инсультом впервые была охарактеризована и выделена в отдельную группу в базе данных Национального института неврологических заболеваний и инсульта США, а впоследствии в исследовании TOAST. Диагноз криптогенного инсульта, как правило, базируется на исключении хорошо известных причин ОНМК, таких как атеросклероз, нарушения ритма сердца, артериальная гипертензия. В связи со значительной вариабельностью понятия криптогенного инсульта в 2014 г. был введен термин ESUS (Embolic Stroke of Undetermined Source — эмболический инсульт с неустановленным источником) и сформулированы критерии, которые четко характеризуют таких пациентов: нелакунарный инфаркт мозга по данным компьютерной и/или магнитно-резонансной томографии, отсутствие атеросклеротического поражения, стенозирующего инсультсвязанную артерию более чем на 50%, отсутствие источников кардиоэмболии высокого риска, отсутствие других причин инсульта, таких как диссекция артерии, питающей область инфаркта мозга, мигрень, артериит. Среди потенциальных причин и источников церебральной эмболии у пациентов с криптогенным инсультом должны быть рассмотрены сердце, вены нижних конечностей и таза, нестенозирующий атеросклероз брахиоцефальных артерий, атеромы дуги аорты, парадоксальная эмболия, неатеросклеротическая васкулопатия, моногенные заболевания, гиперкоагуляционные состояния и др. Следует отметить, что в доступной нам литературе имеется большое количество исследований, посвященных описанию возможных причин криптогенного инсульта, однако единые подходы к систематизации этиологических факторов и протокола обследования пациентов отсутствуют. Высокая частота развития криптогенного инсульта, значительная гетерогенность его этиопатогенетических механизмов, необходимость дифференцированных подходов ко вторичной профилактике данного типа ОНМК обуславливают актуальность дальнейших исследований при данной патологии

Acoustic Overexposure Increases the Expression of VGLUT-2 Mediated Projections from the Lateral Vestibular Nucleus to the Dorsal Cochlear Nucleus

The dorsal cochlear nucleus (DCN) is a first relay of the central auditory system as well as a site for integration of multimodal information. Vesicular glutamate transporters VGLUT-1 and VGLUT-2 selectively package glutamate into synaptic vesicles and are found to have different patterns of organization in the DCN. Whereas auditory nerve fibers predominantly co-label with VGLUT-1, somatosensory inputs predominantly co-label with VGLUT-2. Here, we used retrograde and anterograde transport of fluorescent conjugated dextran amine (DA) to demonstrate that the lateral vestibular nucleus (LVN) exhibits ipsilateral projections to both fusiform and deep layers of the rat DCN. Stimulating the LVN induced glutamatergic synaptic currents in fusiform cells and granule cell interneurones. We combined the dextran amine neuronal tracing method with immunohistochemistry and showed that labeled projections from the LVN are co-labeled with VGLUT-2 by contrast to VGLUT-1. Wistar rats were exposed to a loud single tone (15 kHz, 110 dB SPL) for 6 hours. Five days after acoustic overexposure, the level of expression of VGLUT-1 in the DCN was decreased whereas the level of expression of VGLUT-2 in the DCN was increased including terminals originating from the LVN. VGLUT-2 mediated projections from the LVN to the DCN are likely to play a role in the head position in response to sound. Amplification of VGLUT-2 expression after acoustic overexposure could be a compensatory mechanism from vestibular inputs in response to hearing loss and to a decrease of VGLUT-1 expression from auditory nerve fibers

Stakeholder communication in 140 characters or less: a study of community sport foundations

Community sport foundations (CSFs), like other non-profit organizations, are increasingly employing social media such as Twitter to communicate their mission and activities to their diverse stakeholder groups. However, the way these CSFs utilize social media for communicating such practices remains unclear. Through a mixed-method approach of content analysis of tweets from 22 CSFs established by English professional football clubs and interviews with key individuals within these CSFs (n = 7), this study examines the extent to which CSFs’ core activities are being communicated through Twitter and identifies the strategies employed for doing so. Reflecting the target audiences CSFs are seeking to reach through Twitter and the challenges associated with communication about projects involving marginalized groups, tweets largely concern programs related to sports participation and education. The most frequently employed communication strategy is to inform, rather than interact or engage with stakeholders. However, CSFs with higher organizational capacity attempt to go beyond mere informing towards engaging with stakeholder groups that relate to their social agenda, highlighting the importance of trained and dedicated social media personnel in optimizing CSFs’ use of Twitter for communication