311 research outputs found

    Experimental synchronization of circuit oscillations induced by common telegraph noise

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    Experimental realization and quantitative investigation of common-noise-induced synchronization of limit-cycle oscillations subject to random telegraph signals are performed using an electronic oscillator circuit. Based on our previous formulation [K. Nagai et al., Phys. Rev. E 71, 036217 (2005)], dynamics of the circuit is described as random-phase mappings between two limit cycles. Lyapunov exponents characterizing the degree of synchronization are estimated from experimentally determined phase maps and compared with linear damping rates of phase differences measured directly. Noisy on-off intermittency of the phase difference as predicted by the theory is also confirmed experimentally

    Wound healing and hyper-hydration - a counter intuitive model

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    Winters seminal work in the 1960s relating to providing an optimal level of moisture to aid wound healing (granulation and re-epithelialisation) has been the single most effective advance in wound care over many decades. As such the development of advanced wound dressings that manage the fluidic wound environment have provided significant benefits in terms of healing to both patient and clinician. Although moist wound healing provides the guiding management principle confusion may arise between what is deemed to be an adequate level of tissue hydration and the risk of developing maceration. In addition, the counter-intuitive model ‘hyper-hydration’ of tissue appears to frustrate the moist wound healing approach and advocate a course of intervention whereby tissue is hydrated beyond what is a normally acceptable therapeutic level. This paper discusses tissue hydration, the cause and effect of maceration and distinguishes these from hyper-hydration of tissue. The rationale is to provide the clinician with a knowledge base that allows optimisation of treatment and outcomes and explains the reasoning behind wound healing using hyper-hydration

    Development of voluntary behaviour of senior preschool children using gamification in physical education lessons

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    The article examines the issue of voluntary behaviour as a process aimed at personality development that contributes to the formation of skills necessary for learning at school. Voluntary behaviour manifests itself in various aspects of a child’s life, including play activity. Playing children learn to regulate their behaviour. Games with rules acquire a special role, using game rules children have to act purposefully and overcome difficulties in solving a game task. The study of the level of voluntary behaviour development in senior preschool children was carried out using diagnostic techniques. The results of the study showed that at the beginning of the research the pre-schoolers had low indicators of voluntary behaviour. Therefore, a complex of outdoor games with rules was selected for voluntary behaviour development in senior pre-schoolers since they contain a number accompanying conditions that increase voluntary behaviour

    Role of biomarkers of myocardial injury and inflammation in predicting ischemia-reperfusion injury in patients with ST-segment elevation acute coronary syndrome undergoing endovascular revascularization

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    Aim. To evaluate the informative value of biomarkers (cardiac troponin l (cTnl), high-sensitivity C-reactive protein (hsCRP), N-terminal pro-brain natriuretic peptide (NTproBNP), stimulating growth factor (ST2)) as laboratory markers of myocardial ischemia-reperfusion injury in patients with ST-segment elevation acute coronary syndrome (STEACS) undergoing endovascular revascularization.Material and methods. The study included 115 patients with STEACS who underwent endovascular myocardial revascularization. To identify the informative value of biomarkers, the levels of cTnl, NTproBNP, hsCRP, sST2 were analyzed at baseline, as well as after reperfusion therapy on the 2nd (cTnl) and 5th (sST2, hsCRP, NTproBNP) days. Contrast-enhanced cardiac magnetic resonance imaging was performed 5 days after endovascular intervention.Results. Microvascular obstruction was detected in 54 patients (47%), of which 24 (44%) patients had a combination of microvascular obstruction and myocardial hemorrhage. ln 61 cases (53%), no microvascular damage was registered. lt was found that with an increase in the threshold initial NTproBNP levels >590 pg/ml, the odds ratio (OR) of myocardial reperfusion injury was 12,2 (95% confidence interval (CI), 4,81-30,92, p<0,001). In addition, we analyzed biomarker levels in the early period after myocardial infarction, at which threshold values of reperfusion injury parameters were established as follows: for cTnI >8,1 ng/ml, OR=7,17 (95% CI, 3,11-16,53, p=0,001); for hsCRP >14 mg/L, OR=12,71 (95% CI, 5,03-32,08, p=0,001); for NTproBNP >334 pg/ml, OR=11,8 (95% CI, 4,88-28,59, p=0,001); for sST2 >41 ng/ml, OR=7,17 (95% CI, 3,11-16,53, p=0,001). According to multivariate analysis, predictors of microvascular injury were the initial NTproBNP values, as well as the cTnI, hsCRP, and sST2 values in the early postinfarction period (sensitivity — 89,5%, specificity — 83,3%).Conclusion. Thus, the initial NTproBNP, as well as cTnI, hsCRP, sST2 values after percutaneous coronary intervention are more informative for assessing the risk of microvascular damage

    The jellification of north temperate lakes.

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    Calcium (Ca) concentrations are decreasing in softwater lakes across eastern North America and western Europe. Using long-term contemporary and palaeo-environmental field data, we show that this is precipitating a dramatic change in Canadian lakes: the replacement of previously dominant pelagic herbivores (Ca-rich Daphnia species) by Holopedium glacialis, a jelly-clad, Ca-poor competitor. In some lakes, this transformation is being facilitated by increases in macro-invertebrate predation, both from native (Chaoborus spp.) and introduced (Bythotrephes longimanus) zooplanktivores, to which Holopedium, with its jelly coat, is relatively invulnerable. Greater representation by Holopedium within cladoceran zooplankton communities will reduce nutrient transfer through food webs, given their lower phosphorus content relative to daphniids, and greater absolute abundances may pose long-term problems to water users. The dominance of jelly-clad zooplankton will likely persist while lakewater Ca levels remain low.This work was primarily supported by grants from the Natural Sciences and Engineering Research Council of Canada and funding from the Ontario Ministry of the Environment.This is the accepted manuscript. The final version is available at http://rspb.royalsocietypublishing.org/content/282/1798/20142449

    Kemijski sastav endemske biljke Centaurea austro-anatolica i ispitivanje antimikrobnog djelovanja protiv multi-rezistentnih bakterija

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    Hexane, chloroform, ethyl acetate and ethanolic extracts of the aerial parts of C. austro-anatolica Hub.-Mor. (Asteraceae) were evaluated against microorganisms, including multi-resistant bacteria, using a paper disc diffusion method. The chloroform extract exhibited significant antibacterial activity toward all bacteria tested. The chemical composition of the chloroform extract was determined by gas chromatography (GC) and gas chromatography-mass spectrometry (GC-MS). The major compounds of the extract were caryophyllene oxide (21.32 %), spathulenol (10.86 %), n-tricosanol (9.58 %) and geranyl isovalerate (8.71 %).Heksanski, kloroformski, etil-acetatni i etanolni ekstrakti vršnih dijelova biljke C. austro-anatolica Hub.-Mor. (Asteraceae) ispitivani su na antimikrobno djelovanje protiv multi-rezistentnih bakterija, koristeći difuzijsku metodu na papirnom disku. Kloroformski ekstrakt pokazao je značajno antibakterijsko djelovanje protiv svih testiranih bakterija. Kemijski sastav tog ekstrakta određivan je plinskom kromatografijom (GC) i plinskom kromatografijom-spektrometrijom masa (GC-MS). Najvažniji sastojci ekstrakta bili su kariofilen oksid (21,32 %), spatulenol (10,86 %), n-trikozanol (9,58 %) i geranil izovalerat (8,71 %)

    Voluntary exercise can strengthen the circadian system in aged mice

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    Consistent daily rhythms are important to healthy aging according to studies linking disrupted circadian rhythms with negative health impacts. We studied the effects of age and exercise on baseline circadian rhythms and on the circadian system's ability to respond to the perturbation induced by an 8 h advance of the light:dark (LD) cycle as a test of the system's robustness. Mice (male, mPer2luc/C57BL/6) were studied at one of two ages: 3.5 months (n = 39) and >18 months (n = 72). We examined activity records of these mice under entrained and shifted conditions as well as mPER2::LUC measures ex vivo to assess circadian function in the suprachiasmatic nuclei (SCN) and important target organs. Age was associated with reduced running wheel use, fragmentation of activity, and slowed resetting in both behavioral and molecular measures. Furthermore, we observed that for aged mice, the presence of a running wheel altered the amplitude of the spontaneous firing rate rhythm in the SCN in vitro. Following a shift of the LD cycle, both young and aged mice showed a change in rhythmicity properties of the mPER2::LUC oscillation of the SCN in vitro, and aged mice exhibited longer lasting internal desynchrony. Access to a running wheel alleviated some age-related changes in the circadian system. In an additional experiment, we replicated the effect of the running wheel, comparing behavioral and in vitro results from aged mice housed with or without a running wheel (>21 months, n = 8 per group, all examined 4 days after the shift). The impact of voluntary exercise on circadian rhythm properties in an aged animal is a novel finding and has implications for the health of older people living with environmentally induced circadian disruption

    ИССЛЕДОВАНИЕ ВЛИЯНИЯ ПАССИВИРУЮЩИХ СЛОЕВ НА ЕМКОСТНЫЕ ХАРАКТЕРИСТИКИ ГЕТЕРОСТРУКТУР AlGaN/GaN

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    AlGaN/GaN heterostructures grown by MOCVD method on sapphire and silicon substrates were test subjects. The capacity− voltage characteristic measurements have been run in 200Hz — 1MHz frequency range at planar disposition of mercury and second probe on the sample surface. The shape of typical C−V curves for the heterostructures with the upper undoped i−AlGaN and i−GaN layers at thickness 15—25 A have been analyzed. The appearance of a typical peak on the C−V curves at changing from depletion region to accumulation region has been registered for some structures with thickness of i−GaN layer 50A at low frequencies (f < 50—200 kHz). The height of this peak increased with reduction of frequency. It has been found experimentally that frequency at which the peak is registered can depend on the dislocation density in heterostructures. Possible explanation of the peak formation and band diagram modifications in these structures under an applied electric field have been presented. We show that using a Si3N4 passivation layer results in the formation of additional positive charge.Исследованы гетероструктуры AlGaN/ GaN, выращенные методом МOCVD на сапфировых и кремниевых подложках. Проведены измерения вольт−фарадных характеристик при планарном расположении ртутного зонда и второго электрода на поверхности образцов в диапазоне частот от 200 Гц до 1 МГц. Проанализирован вид типичных С—V−характеристик для гетероструктур с верхними нелегированными слоями i−AlGaN и i−GaN при толщине верхних слоев 1,5—2,5 нм. В ходе исследований при работе на низких частотах (f < 50÷200 кГц) для ряда структур с толщиной слоя i−GaN 5,0 нм при переходе из области обе- днения в область обогащения зафиксировано появление на С—V− кривых характерного пика. Высота этого пика увеличивалась с уменьшением частоты. Экспериментально показано, что частота, при которой фиксировали этот пик, может зависеть от плотности дислокаций в гетероструктурах. Дано возможное объяснение причин появления пиков с учетом модификации зонной диаграммы таких структур при наложении внешних электрических полей. Показано, что использование пассивирующего слоя Si3N4 приводит к возникновению дополнительного положительного заряда в барьерном слое

    The state of the Martian climate

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    60°N was +2.0°C, relative to the 1981–2010 average value (Fig. 5.1). This marks a new high for the record. The average annual surface air temperature (SAT) anomaly for 2016 for land stations north of starting in 1900, and is a significant increase over the previous highest value of +1.2°C, which was observed in 2007, 2011, and 2015. Average global annual temperatures also showed record values in 2015 and 2016. Currently, the Arctic is warming at more than twice the rate of lower latitudes
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