347 research outputs found

    Observation of resonant interactions among surface gravity waves

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    We experimentally study resonant interactions of oblique surface gravity waves in a large basin. Our results strongly extend previous experimental results performed mainly for perpendicular or collinear wave trains. We generate two oblique waves crossing at an acute angle, while we control their frequency ratio, steepnesses and directions. These mother waves mutually interact and give birth to a resonant wave whose properties (growth rate, resonant response curve and phase locking) are fully characterized. All our experimental results are found in good quantitative agreement with four-wave interaction theory with no fitting parameter. Off-resonance experiments are also reported and the relevant theoretical analysis is conducted and validated.Comment: 11 pages, 7 figure

    Influence of flow confinement on the drag force on a static cylinder

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    The influence of confinement on the drag force FF on a static cylinder in a viscous flow inside a rectangular slit of aperture h0h_0 has been investigated from experimental measurements and numerical simulations. At low enough Reynolds numbers, FF varies linearly with the mean velocity and the viscosity, allowing for the precise determination of drag coefficients λ\lambda_{||} and λ\lambda_{\bot} corresponding respectively to a mean flow parallel and perpendicular to the cylinder length LL. In the parallel configuration, the variation of λ\lambda_{||} with the normalized diameter β=d/h0\beta = d/h_0 of the cylinder is close to that for a 2D flow invariant in the direction of the cylinder axis and does not diverge when β=1\beta = 1. The variation of λ\lambda_{||} with the distance from the midplane of the model reflects the parabolic Poiseuille profile between the plates for β1\beta \ll 1 while it remains almost constant for β1\beta \sim 1. In the perpendicular configuration, the value of λ\lambda_{\bot} is close to that corresponding to a 2D system only if β1\beta \ll 1 and/or if the clearance between the ends of the cylinder and the side walls is very small: in that latter case, λ\lambda_{\bot} diverges as β1\beta \to 1 due to the blockage of the flow. In other cases, the side flow between the ends of the cylinder and the side walls plays an important part to reduce λ\lambda_{\bot}: a full 3D description of the flow is needed to account for these effects

    Retrieval Contexts and the Concreteness Effect: Dissociations in Memory of Concrete and Abstract Words

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    Decades of research on the concreteness effect, namely better memory for concrete as compared with abstract words, suggest it is a fairly robust phenomenon. Nevertheless, little attention has been given to limiting retrieval contexts. Two experiments evaluated intentional memory for concrete and abstract word lists in three retrieval contexts: free recall, explicit word-stem completion, and implicit word-stem completion. Concreteness effects were observed in free recall and in explicit word-stem completion, but not in implicit word-stem completion. These findings are consistent with both a bidirectional version of the relational-distinctiveness processing framework (Ruiz-Vargas, Cuevas, & Marschark, 1996) and a second framework combining insights from dual coding theory (Paivio, 1971, 1986) and the transfer appropriate processing framework (Roediger, Weldon, & Challis, 1989). Also, consistent with the relational-distinctiveness framework, the second experiment suggested that concreteness effects might depend on relational processing at encoding: Concreteness effects were observed in explicit memory for related word lists but not for unrelated word lists. © 2005 Psychology Press Ltd

    Antioxidant enzyme levels in intestinal and renal tissues after a 60-minute exercise in untrained mice

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    The present study was designed to determine the effects of exercise on the antioxidant enzymatic system and lipid peroxidation in small intestine and kidney, during the post-exercise period in untrained mice. Two days after the last adaptation running exercise, animals were ran on the treadmill for 60 min at 18 m/min, 5 degrees slope. After the acute exercise the animals were killed by cervical dislocation, immediately (0 h), 3 hours (3 h) and 24 hours (24 h) after the exercise. Control animals were killed without running exercise. Their proximal small intestinal and renal tissues were quickly removed. Changes in the concentration of thiobarbituric acid reactive substance (TBARS), as an index of lipid peroxidation, in intestine and kidney were studied in mice after the running exercise and in unexercised control group. The activities of superoxide dismutase (SOD) and glutathione peroxidase (GPx) were determined in these tissues. Tissue SOD, GPx activities and TBARS level were not increase by the exercise in kidney. Intestinal SOD activity decreased after exercise (0 h and 3 h respectively, p<0.05, p<0.01) and returned to control levels. Intestinal GPx activity increased after exercise (0 h, p<0.05) and returned to control levels. There was no significant difference among groups in intestinal tissue TBARS levels. These findings could suggest that submaximal exercise may not cause oxidative stress in proximal small intestinal tissue and kidney

    Rapid stress system drives chemical transfer of fear from sender to receiver

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    Humans can register another person’s fear not only with their eyes and ears, but also with their nose. Previous research has demonstrated that exposure to body odors from fearful individuals elicited implicit fear in others. The odor of fearful individuals appears to have a distinctive signature that can be produced relatively rapidly, driven by a physiological mechanism that has remained unexplored in earlier research. The apocrine sweat glands in the armpit that are responsible for chemosignal production contain receptors for adrenalin. We therefore expected that the release of adrenalin through activation of the rapid stress response system (i.e., the sympathetic-adrenal medullary system) is what drives the release of fear sweat, as opposed to activation of the slower stress response system (i.e., hypothalamus- pituitary-adrenal axis). To test this assumption, sweat was sampled while eight participants prepared for a speech. Participants had higher heart rates and produced more armpit sweat in the fast stress condition, compared to baseline and the slow stress condition. Importantly, exposure to sweat from participants in the fast stress condition induced in receivers (N = 31) a simulacrum of the state of the sender, evidenced by the emergence of a fearful facial expression (facial electromyography) and vigilant behavior (i.e., faster classification of emotional facial expressions).Netherlands Organization for Scientific Research awar

    Балльно-прогностическая шкала оценки риска ущемления паховых и бедренных грыж

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     Today, algorithms have been developed for actions after excluding hernia incarceration directly during the patient’s hospitalization, but there are no clear recommendations for how to proceed: to offer surgery in this hospitalization or  to recommend planned surgical treatment. To answer this question, it is necessary to assume the probability of repeated incarceration. To solve this  problem, we have suggested high, medium and low risk of incarceration of  inguinal or femoral hernia and determine the optimal timing of surgery.  На сегодняшний день разработан алгоритм действий хирурга при вправившейся ущемленной грыже непосредственно при госпитализации пациента, но нет четких рекомендаций как быть дальше, после исключения ущемления: предлагать операцию в данную госпитализацию  или рекомендовать плановое оперативное  лечение. Чтобы аргументированно ответить на этот вопрос, необходимо прогнозировать вероятность повторного ущемления. Для решения данной проблемы  нами была предложена балльно-прогностическая шкала  оценки риска ущемления паховых и бедренных грыж. Применение данной шкалы на практике позволит выявлять  пациентов с высоким, умеренным и низким риском ущемления  паховой или бедренной грыжи и определять оптимальные  сроки для хирургического лечения.

    Балльно-прогностическая шкала оценки риска ущемления послеоперационных вентральных грыж

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    The problem of treatment for strangulated incisional hernia does not lose its relevance due to the large number of postoperative complications and high mortality rates, which significantly exceed these indicators in selective surgery. One of the solutions to this problem is to identify patients with a high risk of strangulation, which will allow you to perform the operation in a timely manner and avoid possible complications. The most relevant issue is the timing of surgery in patients with postoperative hernias after strangulation. Проблема лечения ущемленных послеоперационных вентральных грыж не теряет своей актуальности по причине большого количества послеоперационных осложнений и высокого уровня летальности, которые значительно превышают данные показатели в плановой хирургии. Один из вариантов решения данной проблемы — выявление пациентов с высоким риском ущемления, что позволит своевременно выполнить плановую операцию и избежать возможных осложнений. Наиболее актуальным является решение вопроса о сроках операции у пациентов с разущемившимися послеоперационными грыжами.

    Assessment of drought resistance in sorghum CMS lines based on various sterility sources

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    Background. Global climate changes have recently led to a more frequent occurrence of adverse factors and a decrease in the productivity of major crops. Sorghum is a highly drought-resistant crop that can tolerate long-term soil and air droughts with much lower harvest losses than wheat or barley. It is important to understand physiological mechanisms affecting drought tolerance when breeding efforts are aimed at improving the adaptability to abiotic conditions and productivity of sorghum hybrids.Materials and methods. Twenty sterile lines of grain sorghum with 8 types of CMS were studied in 2019 and 2020 in the arid conditions of Saratov Province. Indicators of the leaf water regime were assessed according to VIR’s guidelines. Statistical processing of the research results was performed using the AGROS 2.09 software.Results. The indicators of the leaf water regime that reflected differentiated responses of the CMS-line plants to the prevailing water and temperature stressors during the critical flowering period for sorghum were analyzed. Four CMS lines were identified according to the chosen set of indicators: they manifested 71.13–72.02% of total water content, 5.26–9.08% of water deficit, and 57.40–83.17% of water retention capacity on average for the two years of research. For the first time, the effect of CMS in sorghum on the manifestation of water regime indicators was registered. In isonuclear CMS lines, the greatest effect on drought resistance was shown by cytoplasm A3 versus A4 (with the Zheltozernoe 10 genome), cytoplasm A5 versus A1 (with the Karlik 4v genome), and M35-1A versus the analog on cytoplasm 9E (with the Pischevoe 614 genome).Conclusion. It is shown that genetically different types of sterility can be used in breeding practice to increase the resistance to abiotic stressors in components of F1 crosses and hybrids

    Chemical fingerprints of emotional body odor

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    Chemical communication is common among animals. In humans, the chemical basis of social communication has remained a black box, despite psychological and neural research showing distinctive physiological, behavioral, and neural consequences of body odors emitted during emotional states like fear and happiness. We used a multidisciplinary approach to examine whether molecular cues could be associated with an emotional state in the emitter. Our research revealed that the volatile molecules transmitting different emotions to perceivers also have objectively different chemical properties. Chemical analysis of underarm sweat collected from the same donors in fearful, happy, and emotionally neutral states was conducted using untargeted two-dimensional (GC×GC) coupled with time of flight (ToF) MS-based profiling. Based on the multivariate statistical analyses, we find that the pattern of chemical volatiles (N = 1655 peaks) associated with fearful state is clearly different from that associated with (pleasant) neutral state. Happy sweat is also significantly different from the other states, chemically, but shows a bipolar pattern of overlap with fearful as well as neutral state. Candidate chemical classes associated with emotional and neutral sweat have been identified, specifically, linear aldehydes, ketones, esters, and cyclic molecules (5 rings). This research constitutes a first step toward identifying the chemical fingerprints of emotion.info:eu-repo/semantics/publishedVersio

    Turkish Accession and Defining the Boundaries of Nationalism and Supranationalism: Discourses in the European Commission

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    The European Union in general and the European Commission in particular are characterised by supranational governance. The enlargement policy gives the Commission the opportunity to export and promote supranational norms and define the boundaries of Europe as a supranational polity through the conditionality of membership and intensive contact with the candidate countries. This article analyses the discourses of the Commission on Turkey and gives us insights into how well Turkey fits the supranational model in the eyes of Commission officials. It demonstrates how the boundaries of supranationalism are set and even challenged by the prospects of Turkey’s accession
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