Spiders (Aranei) in the vegetation layer of agrocenoses in Leningrad Region, Russia

The research was carried out in 2012–2018 on fields of the Menkovsky Branch of the Agrophysical Research Institute, located in the Gatchina District of Leningrad Region. The study included cenoses of winter rye, winter wheat, spring wheat, spring barley, spring rapeseed, potatoes, narrow-leaved lupine, as well as perennial grasses – a mixture of meadow timothy and red clover. Collection of material on Aranei was timed to the phenological phases of a development of cultivated plants. The species composition, abundance, habitat distribution and population dynamics of spiders were studied in the vegetation layer of agrocenoses. The species composition includes at least 85 species; the abundance is from 0.23 to 1.03 specimens/10 swings of the net, depending on the characteristics of the agrocenosis. The spider complex in the herbage layer consists of representatives of the families Thomisidae, Araneidae, Philodromidae, Tetragnatidae and Lycosidae. The total number of spiders varies noticeably from year to year, increasing significantly in years with heavy rainfalls in June. The highest indices of abundance of spiders were typical for the fields with perennial grasses, and the least of all individuals were caught in the herbage of spring rapeseeds and potatoes. The maximum densities of spiders in the vegetation layer of agrocenoses is observed during the second and third decades of May, species diversity – in the period from the third decade of June to the second decade of Jul

Some mechanisms of winter resistance in apricot flower buds in the period of ecodormancy

Received: March 27th, 2021 ; Accepted: July 6th, 2021 ; Published: August 30th, 2021 ; Correspondence: [email protected] accelerated development of flower buds during the thaw in apricots and almonds during the ecodormancy period leads to significant damage to the flower elements during return frosts and loss of future crops. The aim of the research was to identify the mechanisms of delay in the rate of development of flower buds during the ecodormancy period, their relationship with the degree of frost resistance and the timing of flowering in apricots. The following indicators of flower buds were analyzed: the degree of exit from endodormancy, frost resistance at temperatures of -18 °C and -31 °C, the degree of morphological development of flower elements, the activity of α-amylases at temperatures of + 15 °C and + 60 °C, total content water, phenolcarboxylic acids, flavonoids and free proline. A significant positive correlation was revealed between the percentage of death of flower buds at a temperature of -18 °C and the percentage of buds emerging from endogenous dormancy (0.64*), the percentage of death of buds at a temperature of -31 °C and the degree of development of flower elements (0.70*), water content and the degree of development of flower elements (0.76**), amylase activity at +60 °C and amylase activity at +15 °C (0.76**), the content of phenolcarboxylic acids in the bark of shoots and flower buds (0.61*). For the first time, psychrophilic forms of α-amylases have been discovered in apricot flower buds

Rate-equation approach to atomic-laser light statistics

We consider three- and four-level atomic lasers that are either incoherently (unidirectionally) or coherently (bidirectionally) pumped, the single-mode cavity being resonant with the laser transition. The intra-cavity Fano factor and the photo-current spectral density are evaluated on the basis of rate equations. According to that approach, fluctuations are caused by jumps in active and detecting atoms. The algebra is considerably simpler than the one required by Quantum-Optics treatments. Whenever a comparison can be made, the expressions obtained coincide. The conditions under which the output light exhibits sub-Poissonian statistics are considered in detail. Analytical results, based on linearization, are verified by comparison with Monte Carlo simulations. An essentially exhaustive investigation of sub-Poissonian light generation by three- and four-level atoms lasers has been performed. Only special forms were reported earlier.Comment: 9 pages, 7 figures, RevTeX

Critical temperature of the superfluid transition in bose liquids

A phenomenological criterion for the superfluid transition is proposed, which is similar to the Lindemann criterion for the crystal melting. Then we derive a new formula for the critical temperature, relating $T_{\lambda}$ to the mean kinetic energy per particle above the transition. The suppression of the critical temperature in a sufficiently dense liquid is described as a result of the quantum decoherence phenomenon. The theory can account for the observed dependence of $T_{\lambda}$ on density in liquid helium and results in an estimate $T_{\lambda} \sim 1.1$ K for molecular hydrogen.Comment: 4 pages, 1 fi

Squeezing based on nondegenerate frequency doubling internal to a realistic laser

We investigate theoretically the quantum fluctuations of the fundamental field in the output of a nondegenerate second harmonic generation process occuring inside a laser cavity. Due to the nondegenerate character of the nonlinear medium, a field orthogonal to the laser field is for some operating conditions indepedent of the fluctuations produced by the laser medium. We show that this fact may lead to perfect squeezing for a certain polarization mode of the fundamental field. The experimental feasibility of the system is also discussed.Comment: 6 pages, 5 figure

Динамика морфологических изменений легких при тяжелой черепно-мозговой травме, осложненной аспирацией крови

26 pieces of corpses' lungs died from acute cerebral trauma had been investigated by morphological methods. The purpose of the research work is to estimate the character and time of morphological signs, which characterize acute lung injury. It was obtained that the most early morphological changes in lung - injuries of bronchial mucosa membrane, circulation damages (microcirculation), atelectasis, distelectasis and acute emphysema. Lung edema and signs of systemic inflammation reaction occur during the first hours after the trauma and aspiration.Морфологическими методами исследованы легкие трупов лиц, погибших в результате тяжелой черепно-мозговой травмы, осложненной аспирацией крови (26 наблюдений). Цель исследования - оценить характер и сроки развития морфологических признаков, характеризующих острое повреждение легких. Установлено, что наиболее ранними морфологическими изменениями легких являются: повреждение слизистой оболочки бронхов и бронхиол, расстройства кровообращения (в том числе микроциркуляции), развитие ателектазов, дистелектазов и острой эмфиземы. Отек легких и признаки системной воспалительной реакции формируются в первые часы после травмы и аспирации

Nonequilibrium electron cooling by NIS tunnel junctions

We discuss the theoretical framework to describe quasiparticle electric and heat currents in NIS tunnel junctions in the dirty limit. The approach is based on quasiclassical Keldysh-Usadel equations. We apply this theory to diffusive NIS'S tunnel junctions. Here N and S are respectively normal metal and superconductor reservoirs, I is an insulator layer and S' is a nonequilibrium superconducting lead. We calculate the quasiparticle electric and heat currents in such structures and consider the effect of inelastic relaxation in the S' lead. We find that in the absence of strong relaxation the electric current and the cooling power for voltages $eV < \Delta$ are suppressed. The value of this suppression scales with the diffusive transparency parameter. We ascribe this suppression to the effect of backtunneling of nonequilibrium quasiparticles into the normal metal.Comment: 12 pages, 6 figures, proceedings, to be published in JLT

Time-integrated luminosity recorded by the BABAR detector at the PEP-II e+e- collider

This article is the Preprint version of the final published artcile which can be accessed at the link below.We describe a measurement of the time-integrated luminosity of the data collected by the BABAR experiment at the PEP-II asymmetric-energy e+e- collider at the ϒ(4S), ϒ(3S), and ϒ(2S) resonances and in a continuum region below each resonance. We measure the time-integrated luminosity by counting e+e-→e+e- and (for the ϒ(4S) only) e+e-→μ+μ- candidate events, allowing additional photons in the final state. We use data-corrected simulation to determine the cross-sections and reconstruction efficiencies for these processes, as well as the major backgrounds. Due to the large cross-sections of e+e-→e+e- and e+e-→μ+μ-, the statistical uncertainties of the measurement are substantially smaller than the systematic uncertainties. The dominant systematic uncertainties are due to observed differences between data and simulation, as well as uncertainties on the cross-sections. For data collected on the ϒ(3S) and ϒ(2S) resonances, an additional uncertainty arises due to ϒ→e+e-X background. For data collected off the ϒ resonances, we estimate an additional uncertainty due to time dependent efficiency variations, which can affect the short off-resonance runs. The relative uncertainties on the luminosities of the on-resonance (off-resonance) samples are 0.43% (0.43%) for the ϒ(4S), 0.58% (0.72%) for the ϒ(3S), and 0.68% (0.88%) for the ϒ(2S).This work is supported by the US Department of Energy and National Science Foundation, the Natural Sciences and Engineering Research Council (Canada), the Commissariat à l’Energie Atomique and Institut National de Physique Nucléaire et de Physiquedes Particules (France), the Bundesministerium für Bildung und Forschung and Deutsche Forschungsgemeinschaft (Germany), the Istituto Nazionale di Fisica Nucleare (Italy), the Foundation for Fundamental Research on Matter (The Netherlands), the Research Council of Norway, the Ministry of Education and Science of the Russian Federation, Ministerio de Ciencia e Innovación (Spain), and the Science and Technology Facilities Council (United Kingdom). Individuals have received support from the Marie-Curie IEF program (European Union) and the A.P. Sloan Foundation (USA)

Measurement of the B0-anti-B0-Oscillation Frequency with Inclusive Dilepton Events

The $B^0$-$\bar B^0$ oscillation frequency has been measured with a sample of 23 million \B\bar B pairs collected with the BABAR detector at the PEP-II asymmetric B Factory at SLAC. In this sample, we select events in which both B mesons decay semileptonically and use the charge of the leptons to identify the flavor of each B meson. A simultaneous fit to the decay time difference distributions for opposite- and same-sign dilepton events gives $\Delta m_d = 0.493 \pm 0.012{(stat)}\pm 0.009{(syst)}$ ps$^{-1}$.Comment: 7 pages, 1 figure, submitted to Physical Review Letter

Intercalibration of the barrel electromagnetic calorimeter of the CMS experiment at start-up

Calibration of the relative response of the individual channels of the barrel electromagnetic calorimeter of the CMS detector was accomplished, before installation, with cosmic ray muons and test beams. One fourth of the calorimeter was exposed to a beam of high energy electrons and the relative calibration of the channels, the intercalibration, was found to be reproducible to a precision of about 0.3%. Additionally, data were collected with cosmic rays for the entire ECAL barrel during the commissioning phase. By comparing the intercalibration constants obtained with the electron beam data with those from the cosmic ray data, it is demonstrated that the latter provide an intercalibration precision of 1.5% over most of the barrel ECAL. The best intercalibration precision is expected to come from the analysis of events collected in situ during the LHC operation. Using data collected with both electrons and pion beams, several aspects of the intercalibration procedures based on electrons or neutral pions were investigated