Time-domain Hong-Ou-Mandel interference of quasi-thermal fields and its application in linear optical circuit characterization

We study temporal correlations of interfering quasi-thermal fields, obtained by scattering laser radiation on a rotating ground glass disk. We show that the Doppler effect causes oscillations in temporal cross-correlation function. Furthermore, we propose how to use Hong-Ou-Mandel interference of quasi-thermal fields in the time domain to characterize linear optical circuits.Comment: 8 pages, 5 figures (main), 4 pages, 1 figure (supplemental

Phenological shifts of abiotic events, producers and consumers across a continent

Ongoing climate change can shift organism phenology in ways that vary depending on species, habitats and climate factors studied. To probe for large-scale patterns in associated phenological change, we use 70,709 observations from six decades of systematic monitoring across the former Union of Soviet Socialist Republics. Among 110 phenological events related to plants, birds, insects, amphibians and fungi, we find a mosaic of change, defying simple predictions of earlier springs, later autumns and stronger changes at higher latitudes and elevations. Site mean temperature emerged as a strong predictor of local phenology, but the magnitude and direction of change varied with trophic level and the relative timing of an event. Beyond temperature-associated variation, we uncover high variation among both sites and years, with some sites being characterized by disproportionately long seasons and others by short ones. Our findings emphasize concerns regarding ecosystem integrity and highlight the difficulty of predicting climate change outcomes. The authors use systematic monitoring across the former USSR to investigate phenological changes across taxa. The long-term mean temperature of a site emerged as a strong predictor of phenological change, with further imprints of trophic level, event timing, site, year and biotic interactions.Peer reviewe

Chronicles of nature calendar, a long-term and large-scale multitaxon database on phenology

We present an extensive, large-scale, long-term and multitaxon database on phenological and climatic variation, involving 506,186 observation dates acquired in 471 localities in Russian Federation, Ukraine, Uzbekistan, Belarus and Kyrgyzstan. The data cover the period 1890-2018, with 96% of the data being from 1960 onwards. The database is rich in plants, birds and climatic events, but also includes insects, amphibians, reptiles and fungi. The database includes multiple events per species, such as the onset days of leaf unfolding and leaf fall for plants, and the days for first spring and last autumn occurrences for birds. The data were acquired using standardized methods by permanent staff of national parks and nature reserves (87% of the data) and members of a phenological observation network (13% of the data). The database is valuable for exploring how species respond in their phenology to climate change. Large-scale analyses of spatial variation in phenological response can help to better predict the consequences of species and community responses to climate change.Peer reviewe

Breaking Rayleigh's curse for multi-parameter objects using BLESS technique

According to the Rayleigh criterion, it is impossible to resolve two statistically independent point sources separated by a distance below the width of the point spread function (PSF). Almost twenty years ago it was shown that the distance between two point sources can be statistically estimated with an accuracy better than the PSF width. However, the estimation error increases with decreasing distance. This effect was informally named Rayleigh's curse. Next, it was demonstrated that PSF shaping allows breaking the curse provided that all other source parameters except for the distance, are known a priori. In this work, we propose a new imaging technique based on the target Beam moduLation and the Examination of Shot Statistics (BLESS). Using the Fisher information approach, we show that the technique can break Rayleigh's curse even for unbalanced point sources with unknown centroid and intensity ratio

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Exact mathematical description of the photon annihilation and beam splitter actio

The Skin Potential Level of Facial Biologically Active Zones as Indicators of the Level of Emotional Burnout in Students.

Статичні електричні потенціали (СТЕП) у біологічно активних зонах шкіри (БАЗ) відображають рівень фонової активації мозкових структур і рівень психічного стресу. Мета дослідження – виявити зв’язки СТЕП у симетричних біологічно активних зонах шкіри обличчя з рівнем емоційного вигорання в студентів. Виявлена зворотна кореляція між формуванням емоційного вигорання й рівнем електричного потенціалу шкіри в правих білявушних БАЗ (r s = - .43, р < .05) відносно долоні як референтної ділянки. Знайдено кореляції між розвитком стадії опору вигоранню та фоновими СТЕП у правих і лівих лобних БАЗ (відповідно, r s = - .44 і r s = - .47, р < .05) і СТЕП у лівій лобній БАЗ після впливу негативних кадрів телевізійних новин (r s = - .50, р < .01). Це вказує на те, що формування емоційного вигорання знижує передпускову (до початку експерименту) емоційну напругу й відповідь, тобто силу реакції, на «зовнішні» негативні емоційні стимули. Отримані дані свідчать про те, що електродермальні потенціали можуть служити об’єктивними критеріями формування емоційного вигорання. Emotional burnout syndrome sees as a reaction to stress in interpersonal communication in the form of full or partial shutdown of emotions. V. Boyko dynamic model of burnout that was used as basis of this study classified in 3 stages in accordance with the mechanism of stress. There exist 3 phases: Anxiety Tension, Resistance, and Exhaustion. Strengthening of stressful factors in everyday life triggers the formation of emotional burnout (Anxiety Tension stage). The respondents with «Resistance» stage begin to economize emotion and characterize by emotional and moral disorientation. The central nervous activity reduction and the fall in energy tone are evident in the «Exhaustion» stage. Inadequate reactions to the different stimulus are associated with the hyperreactivity of the nervous system. The skin potential level (SPL) of facial biologically active zones (BAZs) reflects the level of background activation of brain structures and the level of mental stress. That is why skin potential level reflects the formation of emotional burnout. Purpose. The aim of the study was to detect the changes of SPL in symmetric biologically active zones of face skin (frontal, superciliary, paranasal, temporal, periotic and postaural) depending on the level of emotional burnout. Methods. 31 healthy volunteers (women and men) – first-third year students (Mage = 19.07, SD = 1.91 years, from 17 to 23 years) were recruited from the Taras Shevchenko National University of Kyiv, Educational and Scientific Centre «Institute of Biology and Medicine» and Faculty of Psychology, and participated for course credit during preexam period. Skin potential level was recorded via nonpolarizable silver electrodes from the symmetric biologically active zones of face skin (frontal, superciliary, paranasal, temporal, periotic and postaural) with the palm as a reference area. To determine the stages of burnout we used the Boyko «Syndrome of emotional burnout» test adapted for students by Tukaiev and Vasheka. The value of each of Burnout stages was measured on a scale from 0 to 120 points: 0 to 36 points – the stage was not formed, 37 to 60 points – the stage was under development, 61 to 120 points – the stage was formed. The Speerman rank test was carried out for the correlation analysis. Results. Inverse correlation was found between the formation of emotional burnout and the skin potential level in right periotic BAZ (parotid BAZ) (r = - .43, p < .05). We found correlation between the development of the Resistance stage of burnout and background SPL in the right and left frontal BAZ (respectively r = - .44 and r = - .47, p < .05) and SPL in the left frontal BAZ after the exposure of negative frames of documentaries (r = - .50, p < .01). Conclusion. Our data indicates that the formation of burnout reduced the prestarting initial emotional tension and response strength to «external» negative emotional stimuli. It indicates that electrodermal potentials can serve as objective criteria of formation of emotional burnout

Differences in spatial versus temporal reaction norms for spring and autumn phenological events

For species to stay temporally tuned to their environment, they use cues such as the accumulation of degree-days. The relationships between the timing of a phenological event in a population and its environmental cue can be described by a population-level reaction norm. Variation in reaction norms along environmental gradients may either intensify the environmental effects on timing (cogradient variation) or attenuate the effects (countergradient variation). To resolve spatial and seasonal variation in species' response, we use a unique dataset of 91 taxa and 178 phenological events observed across a network of 472 monitoring sites, spread across the nations of the former Soviet Union. We show that compared to local rates of advancement of phenological events with the advancement of temperature-related cues (i.e., variation within site over years), spatial variation in reaction norms tend to accentuate responses in spring (cogradient variation) and attenuate them in autumn (countergradient variation). As a result, among-population variation in the timing of events is greater in spring and less in autumn than if all populations followed the same reaction norm regardless of location. Despite such signs of local adaptation, overall phenotypic plasticity was not sufficient for phenological events to keep exact pace with their cues-the earlier the year, the more did the timing of the phenological event lag behind the timing of the cue. Overall, these patterns suggest that differences in the spatial versus temporal reaction norms will affect species' response to climate change in opposite ways in spring and autumn