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

A discrete slug population model determined by egg production

Slugs are significant pests in agriculture (as well as a nuisance to gardeners), and it is therefore important to understand their population dynamics for the construction of efficient and effective control measures. Differential equation models of slug populations require the inclusion of large (variable) temporal delays, and strong seasonal forcing results in a non-autonomous system. This renders such models open to only a limited amount of rigorous analysis. In this paper, we derive a novel batch model based purely upon the quantity of eggs produced at different times of the year. This model is open to considerable reduction; from the resulting two variable discrete-time system it is possible to reconstruct the dynamics of the full population across the year and give conditions for extinction or global stability and persistence. Furthermore, the steady state temporal population distribution displays qualitatively different behavior with only small changes in the survival probability of slugs. The model demonstrates how small variations in the favorability of different years may result in widely different slug population fluctuations between consecutive years, and is in good agreement with field data

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

Immunologic reactivity of an organism in patients with coxarthrosis in the assessment of risk of development of postoperative complications at the endoprosthesis replacement

It is known that research of immune system using separate parameters doesn't allow to estimate it as one. The aim of the work was to find new approaches to the estimation of immune system state for the determination of character and intensity of immunopathological manifestations in patients with hip joint pathology. We examined immune status in 73 patients with degenerative-dystrophic injuries and in 18 patients with posttraumatic hip joint injuries. We found the most significant immunological indices that allow to determine the state of immune reactivity of the patient before the operation. We identified two groups of patients: with presumably "compensated" and "subcompensated" form of immunodeficient state. It was shown that infectious infectious complications in the area of endoprosthesis appear in patients with low immune reactivity on the basis of calculation of equations of linear function in patients with posttraumatic coxarthrosis. The results of the research showed that it's not necessary to analyze many immunological indices to estimate the state of immune reactivity of an organism. Using discriminant analysis allows to reveal the determinant factors that characterize distinctness of Junctional state of immune system of a certain patient and to determine the risk of development of postoperative complications

Staining method for coronary arteries

Detection of elastic and collagen fibers in the same histological section to determine their relationships and quantification is important for connective tissue investigations. The aim of the study was to assess the possibility of differentiated staining of elastic and collagen fibers with resorcin-fuchsin and fast green FCF in the same histological section and compare the result of this method with the results of the classical methods of staining connective tissue, performed according to standard protocols. Material and methods. We studied adult human hearts, obtained from patients who died from non-cardiac causes. We cut tissue sections from the anterior interventricular artery and the underlying myocardium. After formalin fixation, standard processing and embedding in paraffin of the material, histological sections were made. Histological sections were deparaffinized and immersed resorcin-fuchsin for 15 minutes, then stained with Weigert’s iron hematoxylin for 2 minutes, then for 2 minutes were applied to the preparation surface 0.1% solution of fast green FCF mixed with a saturated solution of picric acid immediately before staining in a ratio of 1:10, the histological sections were dehydrated, cleared and mounted in permanent mounting medium. Results. Elastic fibers were dyed in dark blue, and collagen fibers in different shades of green, which made it possible to differentiate them on the basis of color differences in one histological section. Conclusion. We have developed and tested the method of staining, which provides the possibility of simultaneous detection of elastic and collagen fibers with successive staining with solutions of resorcin-fuchsin and fast green FCF on one histological section

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

Helical bilayer nonbenzenoid nanographene bearing a [10]helicene with two embedded heptagons

The precision synthesis of helical bilayer nanographenes (NGs) with new topology is of substantial interest because of their exotic physicochemical properties. However, helical bilayer NGs bearing non-hexagonal rings remain synthetically challenging. Here we present the efficient synthesis of the first helical bilayer nonbenzenoid nanographene (HBNG1) from a tailor-made azulene-embedded precursor, which contains a novel [10]helicene backbone with two embedded heptagons. Single-crystal X-ray analysis reveals its highly twisted bilayer geometry with a record small interlayer distance of 3.2 Å among the reported helical bilayer NGs. Notably, the close interlayer distance between the two layers offers intramolecular through-space conjugation as revealed by in situ spectroelectrochemistry studies together with DFT simulations. Furthermore, the chiroptical properties of the P/M enantiomers of HBNG1 are also evaluated by circular dichroism and circularly polarized luminescence

Changes in the spectrum of protein components and the concentration of phospholipids of the erythrocyte membrane in patients with ulcerative colitis

Ulcerative colitis is a chronic inflammatory bowel disease with unclear etiology. An insufficient amount of data on the etiopathogenetic mechanisms of the disease creates opportunities to research them at the cellular level, including the membrane level. Since the functional state of the cytoplasmic membrane largely depends on protein-lipid interactions, we studied the effect of the proportional ratio of three proteins (glucose transporter, glyceraldehyde-3-phosphate dehydrogenase (GAPDH) and glutathione-S-transferase (GST)) on the level of phosphatidylethanolamine and phosphatidylcholine in the erythrocyte membrane of patients with ulcerative colitis during an acute attack. The study involved 51 patients with ulcerative colitis during the acute attack and 26 clinically healthy individuals. The groups are comparable by gender and age to study the proteins of the cytoplasmic membrane, Laemmli electrophoresis technique in polyacrylamide gel was used, followed by an assessment of the intensity of protein bands staining on electropherograms. Phospholipid fractions were obtained using thin-layer chromatography and their content was assessed using the Mathcad 2001 Professional system. Statistical processing was carried out by the program Statistica 10.0 for Windows. Changes of phosphatidylcholine and phosphatidylethanolcholine levels in patients and healthy individuals are not of the same type and are interrelated with changes in the proportion of membrane proteins of the glucose transporter, GAPDH and GST. The proportions of proteins that affect the level of phospholipids have calculated. In patients with ulcerative colitis, a decrease in the level of the studied membrane lipids have revealed in comparison with the clinically healthy group, in addition, an increase in the proportion of the glucose transporter and a decrease in the proportion of GST have noted. In addition, the relationship between an increase in the level of the cytoplasmic membrane phospholipids in ulcerative colitis and a change in the proportion of GAFDH in a smaller direction, which slows down the process of glucose oxidation, was determined. The obtained data confirm the strengthening of the processes of antioxidant protection and the increased need for energy supply of the cell membrane in patients with ulcerative colitis during an acute attack