Structure, inter-annual variability, and long-term change in zooplankton communities of the Chukchi Sea

Thesis (Ph.D.) University of Alaska Fairbanks, 2016The Chukchi Sea is a complex transition zone between the Pacific and Arctic Oceans that has been experiencing dramatic change in recent decades due to shifting sea ice cover and increasing temperatures. We examine summer mesozooplankton communities of the Chukchi Sea in Alaskan and Russian waters during summers 2004, 2009, 2010 and 2012 within the scope of the RUSALCA (Russian-American Long Term Census of the Arctic) program. Community structure was highly variable between the study years, but was overall tightly correlated to water mass properties, with bottom temperature being the most significant factor influencing communities. Zooplankton biomass was dominated by the large copepod Calanus glacialis, while abundance was dominated by small shelf species of copepods, such as Pseudocalanus spp. and Oithona similis. The “cold" summers of 2009-2012 had nearly twice the biomass and abundance of zooplankton compared to the oceanographically “warm" summer of 2004. We discuss the implications of the inter-annual variability of planktonic communities within the Chukchi Sea, and the possible effects of longer-term climate change. We then look at distribution and population structure of an ecologically important species complex within the zooplankton, Pseudocalanus spp, and evaluate the implications of a warming climate for this group of copepods. While numerically dominating the communities, Pseudocalanus spp. has been historically understudied at the species level due to very subtle morphological differences between the species. Our approach used a combination of microscopic identification as well as a novel species-specific PCR identification method to discriminate between the four species found in the Chukchi Sea. Our results suggest that shifting oceanographic patterns and climate warming will have unequal impact on this group of organisms, arising from species-specific life histories and tolerance to environmental conditions. These recent observations on zooplankton are then placed into a historical context through comparison to data collected throughout the past half-century (1946-2012). Despite significant challenges associated with the highly variable spatial coverage and methodology of the available datasets, significant trends were detected. In addition to high levels of inter-annual variability, we demonstrate significant increases in zooplankton biomass and abundance in recent years compared to historical studies, as well as shifting distribution ranges for several key species. This signal was most pronounced within the copepods, particularly Calanus glacialis, which appears to be indirectly benefiting from warming of the region. While summer zooplankton communities of the Chukchi Sea have been primarily Bering-Pacific in character for as long as our records exist, continuing warming and ice loss are increasing the influence of Bering-Pacific fauna within the Chukchi region

Изменение представления о цели брака в современных духовных учебных заведениях

The report is one example of the changing attitudes in the national spiritual education. Briefly describes the main provisions of the philosophy of the marriage of the outstanding Russian canonist of the twentieth century — S. V. Troitsky, his methodological principles of the study of this problem. Focuses on the indirect influence of searches of Russian religious philosophy of the early twentieth century setting to change teaching in theological schoolsВ докладе рассматривается один из примеров смены установок в отечественном духовном образовании. Кратко раскрываются основные положения философии брака выдающегося русского канониста ХХ в. — С. В. Троицкого, его методологические принципы в исследовании данной проблемы. Акцентируется внимание на опосредованном влиянии поисков русской религиозной философии начала ХХ в. на смене установок преподавания в духовных учебных заведения

DEM Study of Fluidized Bed Dynamics During Particle Coating in a Spouted Bed Apparatus

A novel process for coating of spherical aerogel particles in a spouted bed is suggested. Using Discrete Element Method the influence of the density and restitution coefficient of experimentally coated aerogels on the fluidized bed dynamics in the developed apparatus was described

Fast diffusion of graphene flake on graphene layer

Diffusion of a graphene flake on a graphene layer is analyzed and a new diffusion mechanism is proposed for the system under consideration. According to this mechanism, rotational transition of the flake from commensurate to incommensurate states takes place with subsequent simultaneous rotation and translational motion until the commensurate state is reached again, and so on. The molecular dynamics simulations and analytic estimates based on ab initio and semi-empirical calculations demonstrate that the proposed diffusion mechanism is dominant at temperatures T ~ Tcom, where Tcom corresponds to the barrier for transitions of the flake between adjacent energy minima in the commensurate states. For example, for the flake consisting of ~ 40, 200 and 700 atoms the contribution of the proposed diffusion mechanism through rotation of the flake to the incommensurate states exceeds that for diffusion of the flake in the commensurate states by one-two orders of magnitude at temperatures 50 - 150 K, 200 - 600 K and 800 - 2400 K, respectively. The possibility to experimentally measure the barriers to relative motion of graphene layers based on the study of diffusion of a graphene flake is considered. The results obtained are also relevant for understanding of dynamic behavior of polycyclic aromatic molecules on graphene and should be qualitatively valid for a set of commensurate adsorbate-adsorbent systems.Comment: 33 pages, 6 figure

Simulation of Atomic Structure Near Nanovoids in BCC Iron

Generally, displacement fields near voids are determined by the equations of elasticity theory. Such a description has its disadvantages as it does not take into account the discrete atomic structure of materials. In this work, we use a new variant of Molecular Static method for investigation of the atomic structure near nanovoids. In our model an iterative procedure is employed, in which the atomic structure in the void vicinity and the parameter determining the displacement of atoms embedded into an elastic continuum are obtained in a self-consistent manner. Results show that the displacements are significantly different for varies crystallographic directions. Keywords: voids; iron; simulation; atomic structure; vacancie

Comparison of expenditure of using experimental models of carcinogenesis

Despite significant advances in the diagnosis and treatment of oncopathology, the main epidemic indicators have a negative trend.Based on the above, a very relevant topic is the development of experimental models of carcinogenesis. The importance of scientific work in this area is increasing because in experimental conditions it is better to test new methods, diagnostics and treatment. Thus, it becomes possible to study the peculiarities of the pathogenesis of any tumor at different stages.The purpose of the work – to study and demonstrate the strengths and weaknesses of the main experimental models of carcinogenesis for further selection of the most appropriate.Results The main directions of carcinogenesis modeling are presented in the article. Initially, the problem was justified. The next step is described in chronological order of using the models.Of course, the achievements of clinical and experimental oncology played an important role in the emergence of models. Thus, the first model was the effect of physical and chemical carcinogens on a laboratory animal. The latest achievement of experimental oncology is the use of stem cells in combination with genetic engineering.No less important is the fact of comparing experimental models. We present the strengths and weaknesses of all these models.Conclusions1. To date, there are a large number of experimental models of carcinogenesis.2. When planning a study, you need to calculate all the goals to be achieved and select the appropriate model.3. The most effective and common model for ascites ovarian tumor is the transplantation of atypical cells to laboratory animals