Isoperiodic deformations of the acoustic operator and periodic solutions of the Harry Dym equation

We consider the problem of describing the possible spectra of an acoustic operator with a periodic finite-gap density. We construct flows on the moduli space of algebraic Riemann surfaces that preserve the periods of the corresponding operator. By a suitable extension of the phase space, these equations can be written with quadratic irrationalities.Comment: 15 page

“Siena Case”: the Political Development of the Siena of the Renaissance in Historiography of the Second Half of XX-XXI Centuries

The basic approaches to the study of the political development and government of Siena, one of the Italian republics of the Renaissance, are examined. The works of Western, especially Italian, historians of the second half of the XX - beginning of the XXI centuries are analyzed. The novelty of the study is that the author summarizes the results of studying the problem, shows the evolution of approaches to its solution, introduces the reader to modern views on it. An urgent question about the specifics of the Renaissance state by the example of the formation of Siena statehood in the second half of the XIV - first half of the XVI centuries has been raised. Based on a study of the works touching upon this problem, the author shows that during the study period the issue of the features of Siena’s political and state development was considered from different perspectives and underwent evolution from the problem of the decline of Siena to the problems of autonomy of the Siena state within the “Medici state”. Analysis of Western historiography of this period leads the author to agree with the conclusions of Italian scientists that the formation of a system of “parties” and coalition governments in Siena determines not only the relatively late formation of Signoria Petrucci, but also the specifics of Siena’s political and state development a kind of historical alternative to the Florentine signoria

Breeding behavior and pup development of the Caspian seal, Pusa caspica

The Caspian seal, Pusa caspica, is an ice-breeding phocid endemic to the Caspian Sea. The breeding behavior of this species is poorly documented. Here, we report behavioral observations of 518 mother-pup pairs and 210 lone pups, made from the bridge of icebreakers traversing seal breeding grounds while servicing oil installations in the northeastern Caspian Sea, during 34 trips from late January to early March, 2006-2012. The breeding habitat of Caspian seals is land-fast or drift ice, usually at least 20 cm thick, overlying water 3–5 m deep. Pregnant females formed pairs or small groups. They were not observed to use lairs, but preferentially pupped beside ice ridges or ice-slab piles that afforded shelter to pups. In years when there were few natural leads into the ice-field, females often gave birth on the edge of artificial leads formed by shipping channels. Pups were categorized into stages from newborn (1), white-coat (2), molting (3), and molted (4), with Stage 3 and 4 pups appearing from mid to late February. The nursing period lasted at least 3 weeks and neighboring mother-pup pairs appeared to be mutually tolerant. Mothers left their pups alone or at nursery sites, presumably to forage. Most white-coat pups moved over the ice while avoiding water in response to disturbance from vessels. Mother-pup pairs maintained contact while moving across the ice by a combination of the pup’s following response and diligent chaperoning by the mother. During disturbances some lone pups sought refuge in shelters under ice slabs, whereas others followed a neighboring mother-pup pair away from the vessel. Male-female pairing occurred in late season with no male-male competition observed on the ice. While breeding and pup rearing behavior of Caspian seals has some features in common with that of other Holarctic seals, it is largely distinct and adapted to the unique conditions of the Caspian environment, in particular the paucity of snow cover on the ice

DNA double-strand breaks induced by high NaCl occur predominantly in gene deserts

High concentration of NaCl increases DNA breaks both in cell culture and in vivo. The breaks remain elevated as long as NaCl concentration remains high and are rapidly repaired when the concentration is lowered. The exact nature of the breaks, and their location, has not been entirely clear, and it has not been evident how cells survive, replicate, and maintain genome integrity in environments like the renal inner medulla in which cells are constantly exposed to high NaCl concentration. Repair of the breaks after NaCl is reduced is accompanied by formation of foci containing phosphorylated H2AX (γH2AX), which occurs around DNA double-strand breaks and contributes to their repair. Here, we confirm by specific comet assay and pulsed-field electrophoresis that cells adapted to high NaCl have increased levels of double-strand breaks. Importantly, γH2AX foci that occur during repair of the breaks are nonrandomly distributed in the mouse genome. By chromatin immunoprecipitation using anti-γH2AX antibody, followed by massive parallel sequencing (ChIP-Seq), we find that during repair of double-strand breaks induced by high NaCl, γH2AX is predominantly localized to regions of the genome devoid of genes (“gene deserts”), indicating that the high NaCl-induced double-strand breaks are located there. Localization to gene deserts helps explain why the DNA breaks are less harmful than are the random breaks induced by genotoxic agents such as UV radiation, ionizing radiation, and oxidants. We propose that the universal presence of NaCl around animal cells has directly influenced the evolution of the structure of their genomes

Magnetism and magnetic phase transition in nanowires of diamagnetically diluted superstrong magnets ε-InxFe1-xO3

The temperature dependences of magnetization of ordered arrays of diamagnetically diluted nanoparticles of superstrong ε-InxFe1-xO3 magnets (x = 0.04, 0.24) in cooling and heating mode in the permanent magnetic fields of different strengths -strong and weak compared to the magnetic anisotropy field -were measured. At temperatures of 150 K for x = 0.04 and 190 K for x = 0.24 a sharp drop in their magnetization is observed, practically to zero. Obtained evidence that the observed magnetic phase transition is accompanied by overturning of magnetization due to spin-reorientation transition of the first kind. The experimental results are described within the magnetodynamic and thermodynamic approaches

Individual variation in seasonal movements and foraging strategies of a land-locked, ice-breeding pinniped

Marine mammal satellite telemetry studies can provide important tests of movement and foraging theory. Here we present the first satellite tracking study of Caspian seals (Pusa caspica), an endangered, ice-breeding phocid seal, endemic to the Caspian Sea. The Caspian Sea is one of the most variable habitats inhabited by any pinniped species, and lacks competing large piscivores. Under such conditions foraging theory predicts individual variation in foraging strategy may develop to reduce intra-species competition. We deployed 75 Argos satellite tags 2009-2012 on adult seals of both sexes, and used State Space Modelling to describe movement, and behavioural states. During winter in all years most individuals were mobile within the icepack, making repeated trips into open water outside the ice field, with only brief stationary periods that may be related to breeding activity. During summer 2011, 60% of tagged animals migrated into the mid and southern Caspian, while the remainder spent the ice free season in the north. Summer foraging locations were not restricted by proximity to haul out sites, with animals spending more than 6 months at sea. Maximum dive depths exceeded 200m, and maximum duration was greater than 20 minutes, but 80% of dives were shallower than 15m and shorter than 5 minutes. Hierarchical cluster analysis identified 3 distinct groups of summer dive behaviour, comprising shallow, intermediate and deep divers, which were also spatially exclusive, suggesting potential niche partitioning and individual specialisation on prey or habitat types. The results can contribute to assessment of impacts from anthropogenic activities and to designation of protected areas encompassing critical habitats

Economic tools for realization of methane production project on Kuzbass coal deposits

Environmental issues and, above all, issues related to the release of greenhouse gases into the atmosphere, such as coal bed methane, actualize the challenge of searching a variety of options for its disposal. The difference in the macroeconomic, industrial, geological and infrastructural features determine the need to choose the most cost-effective option for using of methane emitted from the coal deposits. Various economic ways to improve the profitability of production are viewed on the basis of the analysis of methane production project from Kuzbass coal deposits, Kemerovo region, Russia

Mutations in human genes that increase the risk for severe influenza infection

The system of genetic control of innate immune responses to influenza infection and gene function allows for the development of systemic treatment of influenza with a focus on the phenotype of mutations based on individual genetic susceptibility to severe disease and/or the development of complications.The system of genetic control of innate immune responses to influenza infection and gene function allows for the development of systemic treatment of influenza with a focus on the phenotype of mutations based on individual genetic susceptibility to severe disease and/or the development of complications

Inter-year variation in pup production of Caspian seals (Pusa caspica) 2005-2012 determined from aerial surveys

Assessing species abundance and reproductive output is crucial for evaluations of population dynamics, conservation status and the development of management objectives. The Caspian seal (Pusa caspica) is a key predator in the Caspian Sea ecosystem and is listed as “Endangered” by IUCN. Here we report on fixed-wing aerial strip transect surveys of the breeding population on the Caspian Sea winter ice field carried out in February 2005-2012. Potential detection biases were estimated by applying a Petersen mark-recapture estimator to the counts from double photographic observations. We also tested for effects of weather conditions on count results, and for correlations between pup production and ice conditions and net primary productivity (npp). Fluctuations in pup production estimates were observed among years, ranging from 8,200 pups (95% CI 7,130-9342) in 2010 to 34,000 (95% CI 31,275-36,814) in 2005. Total adults on the ice ranged from 14,500 in 2010 to 66,300 in 2012. We did not detect significant associations between pup production and either ice summary data (ice season length, and ice area) or npp. The observed inter-year variation may be partly due to underlying biological drivers influencing the fecundity of the population, although measurement errors arising from observation bias, plus variation in survey timing and weather conditions may also have contributed. Identifying the potential drivers of Caspian seal population dynamics will require extending both the survey time series and the quality of supporting data. However, inter-year fluctuations should still cause concern that the population may be vulnerable to environmental variability and ecosystem dynamics

One-Dimensional Discrete Stark Hamiltonian and Resonance Scattering by Impurities

A one-dimensional discrete Stark Hamiltonian with a continuous electric field is constructed by extension theory methods. In absence of the impurities the model is proved to be exactly solvable, the spectrum is shown to be simple, continuous, filling the real axis; the eigenfunctions, the resolvent and the spectral measure are constructed explicitly. For this (unperturbed) system the resonance spectrum is shown to be empty. The model considering impurity in a single node is also constructed using the operator extension theory methods. The spectral analysis is performed and the dispersion equation for the resolvent singularities is obtained. The resonance spectrum is shown to contain infinite discrete set of resonances. One-to-one correspondence of the constructed Hamiltonian to some Lee-Friedrichs model is established.Comment: 20 pages, Latex, no figure