Site-fidelity and spatial movements of western North Pacific gray whales on their summer range off Sakhalin, Russia

The Western North-Pacific (WNP) gray whale feeding grounds are off the northeastern coast of Sakhalin Island, Russia and is comprised of a nearshore and offshore component that can be distinguished by both depth and location. Spatial movements of gray whales within their foraging grounds were examined based on 13 years of opportunistic vessel and shore-based photo-identification surveys. Site fidelity was assessed by examining annual return and resighting rates. Lagged Identification Rates (LIR) analyses were conducted to estimate the residency and transitional movement patterns within the two components of their feeding grounds. In total 243 individuals were identified from 2002-2014, among these were 94 calves. The annual return rate over the period 2002-2014 was 72%, excluding 35 calves only seen one year. Approximately 20% of the individuals identified from 2002-2010 were seen every year after their initial sighting (including eight individuals that returned for 13 consecutive years). The majority (239) of the WNP whales were observed in the nearshore area while only half (122) were found in the deeper offshore area. Within a foraging season, there was a significantly higher probability of gray whales moving from the nearshore to the offshore area. No mother-calf pairs, calves or yearlings were observed in the offshore area, which was increasingly used by mature animals. The annual return rates, and population growth rates that are primarily a result of calf production with little evidence of immigration, suggest that this population is demographically self-contained and that both the nearshore and offshore Sakhalin feeding grounds are critically important areas for their summer annual foraging activities. The nearshore habitat is also important for mother-calf pairs, younger individuals, and recently weaned calves. Nearshore feeding could also be energetically less costly compared to foraging in the deeper offshore habitat and provide more protection from predators, such as killer whales

Electron and hole g-factors and spin dynamics of negatively charged excitons in CdSe/CdS colloidal nanoplatelets with thick shells

We address spin properties and spin dynamics of carriers and charged excitons in CdSe/CdS colloidal nanoplatelets with thick shells. Magneto-optical studies are performed by time-resolved and polarization-resolved photoluminescence, spin-flip Raman scattering and picosecond pump-probe Faraday rotation in magnetic fields up to 30 T. We show that at low temperatures the nanoplatelets are negatively charged so that their photoluminescence is dominated by radiative recombination of negatively charged excitons (trions). Electron g-factor of 1.68 is measured and heavy-hole g-factor varying with increasing magnetic field from -0.4 to -0.7 is evaluated. Hole g-factors for two-dimensional structures are calculated for various hole confining potentials for cubic- and wurtzite lattice in CdSe core. These calculations are extended for various quantum dots and nanoplatelets based on II-VI semiconductors. We developed a magneto-optical technique for the quantitative evaluation of the nanoplatelets orientation in ensemble

Addressing the exciton fine structure in colloidal nanocrystals: the case of CdSe nanoplatelets

We study the band-edge exciton fine structure and in particular its bright-dark splitting in colloidal semiconductor nanocrystals by four different optical methods based on fluorescence line narrowing and time-resolved measurements at various temperatures down to 2 K. We demonstrate that all these methods provide consistent splitting values and discuss their advances and limitations. Colloidal CdSe nanoplatelets with thicknesses of 3, 4 and 5 monolayers are chosen for experimental demonstrations. The bright-dark splitting of excitons varies from 3.2 to 6.0 meV and is inversely proportional to the nanoplatelet thickness. Good agreement between experimental and theoretically calculated size dependence of the bright-dark exciton slitting is achieved. The recombination rates of the bright and dark excitons and the bright to dark relaxation rate are measured by time-resolved techniques

Modeling of the plasticity of microstructured and nanostructured materials

A new approach to modeling of the plasticity of materials with nanostructure and ultrafine one has been proposed. Its main advantage is the minimum number of physical parameters in use. In the context of the proposed model, we calculated the volumetric density of the energy of surface tension of the material grains. This energy is a significant part of the internal energy during deformation. The size dependence of the melting temperature of nanoparticles was compared with experimental data. We obtained size dependence of the yield point on its basis. Yield point was interpreted as the result of changes of grains surface energy during the deformation. The obtained yield point dependence on the grain size was related to the Hall–Petch law, and this resulted in confirmation of the hypothesis on the crucial role of surface tension forces in the initial stage of plastic deformation of ultrafine materials

Surface vs diffusion in TDS of hydrogen

The paper addresses the numerical simulation of conditions in which the measurement of thermal desorption spectra of hydrogen (TDS) is carried out. Plane steel samples of 10 mm thickness were used as the specimens for simulation. The skin effect which is observed with standard hydrogen charging of samples was accounted for the initial conditions. The standard diffusion of hydrogen was simulated according to Fick’s law. Solution of the Fick’s equation is obtained by finite element methods using the developed code. The resulting solutions show that standard hydrogen charging can lead to the appearance of an additional TDS peak, even without taking into account the traps. New interpretation of the TDS method for hydrogen dissolved in a solid was suggested

The First Results of Application of Novel Biopolymers in Surgery and Medicine and their Potentials

В статье проанализированы результаты пионерных ограниченных клинических испытаний высокотехнологичных изделий медицинского назначения, изготовленных из полигидрокисалканоатов (ПГА) – разрушаемых биополимеров микробиологического происхождения: сетчатых эндопротезов, модифицированных покрытием из ПГА для хирургического лечения паховых грыж, эндобилиарных стентов для лечения больных с механической желтухой, вызванной непроходимостью внепеченочных желчных протоков различной этиологии, а также биодеградируемых моножильных хирургических нитей для ушивания послеоперационных ран передней брюшной стенки. Дана сравнительная характеристика вышеперечисленных изделий с российскими и зарубежными аналогами, широко используемыми в клинике. Доказано влияние выбора изделий на частоту ранних и поздних послеоперационных осложнений, представлены различные лабораторные и клинические показатели и перспективность применения экспериментальных изделий из ПГА в реконструктивной хирургии.The paper reports analysis of results of the first limited clinical trials of high technology medical devices prepared using polyhydroxyalkanoates (PHAs) – degradable microbial biopolymers: PHA coated mesh stents for surgical repair of inguinal hernia, endobiliary stents for treatment of the patients with obstructive jaundice caused by extrahepatic biliary obstruction due to different reasons, and biodegradable monofilament sutures for closing operative wounds on the abdominal wall. The devices were compared with their commercial Russian and foreign analogs widely used clinically. The choice of the device influenced the incidence of early and delayed postsurgical complications and laboratory and clinical parameters. The study proves the suitability of PHA-based devices for reconstructive surgery

The First Results of Application of Novel Biopolymers in Surgery and Medicine and their Potentials

В статье проанализированы результаты пионерных ограниченных клинических испытаний высокотехнологичных изделий медицинского назначения, изготовленных из полигидрокисалканоатов (ПГА) – разрушаемых биополимеров микробиологического происхождения: сетчатых эндопротезов, модифицированных покрытием из ПГА для хирургического лечения паховых грыж, эндобилиарных стентов для лечения больных с механической желтухой, вызванной непроходимостью внепеченочных желчных протоков различной этиологии, а также биодеградируемых моножильных хирургических нитей для ушивания послеоперационных ран передней брюшной стенки. Дана сравнительная характеристика вышеперечисленных изделий с российскими и зарубежными аналогами, широко используемыми в клинике. Доказано влияние выбора изделий на частоту ранних и поздних послеоперационных осложнений, представлены различные лабораторные и клинические показатели и перспективность применения экспериментальных изделий из ПГА в реконструктивной хирургии.The paper reports analysis of results of the first limited clinical trials of high technology medical devices prepared using polyhydroxyalkanoates (PHAs) – degradable microbial biopolymers: PHA coated mesh stents for surgical repair of inguinal hernia, endobiliary stents for treatment of the patients with obstructive jaundice caused by extrahepatic biliary obstruction due to different reasons, and biodegradable monofilament sutures for closing operative wounds on the abdominal wall. The devices were compared with their commercial Russian and foreign analogs widely used clinically. The choice of the device influenced the incidence of early and delayed postsurgical complications and laboratory and clinical parameters. The study proves the suitability of PHA-based devices for reconstructive surgery