Deep and extensive meltwater system beneath the former Eurasian Ice Sheet in the Kara Sea

Abstract The Eurasian ice sheet extended across the Barents and Kara Seas during the late Quaternary, yet evidence on past ice dynamics and thermal structure across its huge eastern periphery remains largely unknown. Here we use three-dimensional seismic data sets covering ∼4500 km2 of the Kara Sea west of Yamal Peninsula, Siberia (71°–73°N), to identify, for the first time in the Russian Arctic seas, several buried generations of vast subglacial tunnel valley networks. Individual valleys are up to 50 km long and are incised as much as 400 m deep; among the largest tunnel valleys ever reported. This discovery represents the first documentation of an extensively warm-based eastern margin of the Eurasian ice sheet during the Quaternary glaciations. The presence of major subglacial channel networks on the shallow shelf, with no evidence of ice streaming, suggests that significant meltwater discharge and subsequent freshwater forcing of ocean circulation may be long-lived rather than catastrophic, occurring during the latest stages of deglaciation in areas where the ice sheet flows slowly and is grounded largely above sea level. Furthermore, the first account of an extensive hydrological network across large areas of the Kara Sea provides important empirical evidence for active subglacial hydrological processes that should be considered in future numerical modeling of the eastern margin of the Quaternary Eurasian ice sheet.</jats:p

A comparison of the two approaches of the theory of critical distances based on linear-elastic and elasto-plastic analyses

The problem of determining the strength of engineering structures, considering the effects of the non-local fracture in the area of stress concentrators is a great scientific and industrial interest. This work is aimed on modification of the classical theory of critical distance that is known as a method of failure prediction based on linear-elastic analysis in case of elasto-plastic material behaviour to improve the accuracy of estimation of lifetime of notched components. Accounting plasticity has been implemented with the use of the Simplified Johnson-Cook model. Mechanical tests were carried out using a 300 kN electromechanical testing machine Shimadzu AG-X Plus. The cylindrical un-notched specimens and specimens with stress concentrators of titanium alloy Grade2 were tested under tensile loading with different grippers travel speed, which ensured several orders of strain rate. The results of elasto-plastic analyses of stress distributions near a wide variety of notches are presented. The results showed that the use of the modification of the TCD based on elasto-plastic analysis gives us estimates falling within an error interval of ±5-10%, that more accurate predictions than the linear elastic TCD solution. The use of an improved description of the stress-strain state at the notch tip allows introducing the critical distances as a material parameter

On the use of the Theory of Critical Distances to estimate the dynamic strength of notched 6063-T5 aluminium alloy

In this paper the so-called Theory of Critical Distances is reformulated to make it suitable for estimating the strength of notched metals subjected to dynamic loading. The TCD takes as its starting point the assumption that engineering materials’ strength can accurately be predicted by directly post-processing the entire linear-elastic stress field acting on the material in the vicinity of the stress concentrator being assessed. In order to extend the used of the TCD to situations involving dynamic loading, the hypothesis is formed that the required critical distance (which is treated as a material property) varies as the loading rate increases. The accuracy and reliability of this novel reformulation of the TCD was checked against a number of experimental results generated by testing notched cylindrical bars of Al6063-T5. This validation exercise allowed us to prove that the TCD (applied in the form of the Point, Line, and Area Method) is capable of estimates falling within an error interval of ±20%. This result is very promising especially in light of the fact that such a design method can be used in situations of practical interest without the need for explicitly modelling the non-linear stress vs. strain dynamic behaviour of metals

Dental evidence for variation in diet over time and space in the Arctic fox, Vulpes lagopus

Studies of the effects of variation in resource availability are important for understanding the ecology of high-latitude mammals. This paper examines the potential of dental evidence (tooth wear and breakage) as a proxy for diet and food choice in Vulpes lagopus, the Arctic fox. It presents a preliminary study of dental microwear, gross wear score, and tooth breakage in a sample (n = 78 individuals) from the Yamal Peninsula of the Russian Arctic. While these measures have each been associated with feeding ecology in larger carnivorans (e.g., proportion of bone in the diet), they have yet to be combined in any study and have rarely been applied to smaller species or those from high latitudes. Arctic foxes from the north and south of the peninsula, and those from rodent peak and trough density periods, are compared to assess impact of changes in food availability across space and time. Results indicate that microwear textures vary in dispersion, with more variation in texture complexity, including higher values (suggesting more consumption of bone), in the rodent-poor period in the north of Yamal. Gross wear scores and tooth breakage are also significantly higher for the north of Yamal than the south. These data together suggest that dental evidence can provide important insights into variation in the feeding ecology of Arctic foxes and potentially into the impacts of changes in food abundance across space and time

Dental evidence for variation in diet over time and space in the Arctic fox, Vulpes lagopus

Studies of the effects of variation in resource availability are important for understanding the ecology of high-latitude mammals. This paper examines the potential of dental evidence (tooth wear and breakage) as a proxy for diet and food choice in Vulpes lagopus, the Arctic fox. It presents a preliminary study of dental microwear, gross wear score, and tooth breakage in a sample (n = 78 individuals) from the Yamal Peninsula of the Russian Arctic. While these measures have each been associated with feeding ecology in larger carnivorans (e.g., proportion of bone in the diet), they have yet to be combined in any study and have rarely been applied to smaller species or those from high latitudes. Arctic foxes from the north and south of the peninsula, and those from rodent peak and trough density periods, are compared to assess impact of changes in food availability across space and time. Results indicate that microwear textures vary in dispersion, with more variation in texture complexity, including higher values (suggesting more consumption of bone), in the rodent-poor period in the north of Yamal. Gross wear scores and tooth breakage are also significantly higher for the north of Yamal than the south. These data together suggest that dental evidence can provide important insights into variation in the feeding ecology of Arctic foxes and potentially into the impacts of changes in food abundance across space and time

Chemiluminescence analysis of biological fluids in herpetic infection in Children

Chemiluminescent analysis of tears, oral fluid, plasma and red blood cells of children with herpetic keratitis, as well as oral fluid, plasma and red blood cells of children with acute herpetic stomatitis in the course of the disease was carried out. With herpetic infection, the intensity of the chemiluminescence indices of the tear and oral fluid correlates with the indices of plasma and blood erythrocytes. In the case of an ophthalmoherpes, an increase in the maximum flash intensity, a light sum of chemiluminescence, and a light sum after the maximum value of chemiluminescence in a tear testifies to the intensification of free radical oxidation. In acute herpetic stomatitis the parameters of chemiluminescence of oral fluid, plasma and red blood cells correlate with the severity of the disease. The high sensitivity of chemiluminescent analysis of tears and saliva can be recommended as a non-invasive method of assessing the effectiveness of treatment of herpetic infection in children.Проведен хемилюминесцентный анализ слезы, ротовой жидкости, плазмы и эритроцитов крови детей при герпетическом кератите, а также ротовой жидкости, плазмы и эритроцитов крови детей при остром герпетическом стоматите в динамике заболевания. При герпетической инфекции интенсивность показателей хемилюминесценции слезы и ротовой жидкости коррелирует с показателями плазмы и эритроцитов крови. При офтальмогерпесе увеличение показателей максимальной интенсивности вспышки, светосуммы хемилюминесценции, светосуммы после максимального значения хемилюминесценции в слезе свидетельствует об интенсификации свободнорадикального окисления. При остром герпетическом стоматите показатели хемилюминесценции ротовой жидкости, плазмы и эритроцитов крови коррелируют с тяжестью заболевания. Высокая чувствительность хемилюминесцентного анализа слезы и ротовой жидкости позволяет рекомендовать его как неинвазивный метод оценки эффективности лечения герпетической инфекции у детей

THE RESEARCH OF THE COMPOSITION OF SAFFLOWER SEED OIL OBTAINED BY METHOD OF COLD PRESSING

Safflower - oil crops, the seeds contain 25-37 % provisious oil and 12% protein. The object of the research used seeds of safflower varieties Iris. Studies of the fatty acid composition of safflower oil obtained by method cold pressing. It established that omega-6 fatty acids predominate in safflower oil.It is established that in safflower oil fatty acids of 18 and 16 groups prevail, the content of other fatty acids in the sum makes 1,2 %In the test sample there is a predominance of omega-6 fatty acids (concentration of 80 % linoleic and γ-linolenic fatty acids). The article presents the research of fatty acid composition of safflower oil obtained by method cold pressing. It established that in safflower oil fatty acids of 18 and 16 groups prevail, the content of other fatty acids in the sum makes 1,2 %. In the studied sample there is a predominance of omega-6 fatty acids (concentration of 80 % linoleic and γ-linolenic fatty acids). Also defined physic-chemical characteristics of safflower oil: the acid number AN = 1, 07 mg KOH/g, peroxide number PN = 8, 09 mmol/кгО2, anisidin number AN = 3,25. Humidity safflower oil 0,03 %. The obtained values for the qualitative characteristics indicate the advantages of using this type of oil: directly for food, as well as for the production of oilseeds, such as mayonnaise, sauces, spreads; as biofuel; when designing and optimizing the recipe-tour of animal feed

Factors of negative psycho-emotional states among women undergoing IVF treatment. .

Open access publication In Russian (Abstract and References in English) The article presents the results of a study of clinical and psychological factors of mental and emotional states among women (N=127) with the extracorporal fertilization (IVF) treatment. There are analyzed data from clinical interviews (type of infertility (female, male), cause of infertility, the planning time of pregnancy, number of attempts and the kind of IVF experiences of relationships in the parent family and with husband, self-relationship and health) and socio-demographic indicators (nature of work, type of marriage and number of marriages, the availability and scheduling of children). There are analyzed the relationship of these indicators with personal and situational anxiety. In the group among women with a female infertility a personal and situational anxiety were higher. Personal anxiety is higher among women with negative mental states (apathy, depression, emotional fatigue, high anxiety, and sleep disturbance, obsessive thoughts about pregnancy, fears, panic attacks), than among women with somatic problems (physical fatigue, lack of sexual desire, hormonal imbalance, endocrine disorders, vascular dystonia, cystitis, eye problems, problems with the musculoskeletal system). There is a need in further research to clarify causal relationships between personal characteristics and negative mental states, and other risk factors, such as problems in the relationship. Personal anxiety is higher among women who indicated relationship problems with their husbands. More severe anxiety among women with children (their own, husband’s) can indicate the complexity of personal experiences and the system of motives of pregnancy that requires a differentiated approach in the psychological support to this category of women with the treatment on the IVF program. The obtained data testify that the characteristics and dynamics of the mental states among women in the program of IVF treatment can be associated with the causes of infertility; negative experience of relationships in the parent family, especially the authoritarian and emotionally cold relationship with the mother; the personal qualities among women, the nature of the dominant reproductive motives, which in turn are connected with the peculiarities of the social situation (marriage, children); the time of pregnancy planning, which may be due to the type (female, male) reproductive health problems and the number of IVF attempts. The identification of the relationships and interdependency of these factors, the nature of their impact on the treatment process, the course and outcome of pregnancy in cases of external reproductive technologies need further study in longitudinal and comparative studies on larger samples of respondents. The obtained data allow: to carry out early diagnostics of social and psychological factors that impede the process of infertility treatment methods of assisted reproduction; to carry out psychological prevention of the formation of negative mental states and targeted psychological assistance in medical treatment with the IVF program

The Impact of Maternal Overweight on Hair Essential Trace Element and Mineral Content in Pregnant Women and Their Children

The aim of the present study was to investigate hair essential trace elements and mineral levels in 105 pregnant normal-weight (control) and 55 overweight and obese women in the third trimester of pregnancy, as well as in their children at the age of 9 months. The hair essential trace elements and mineral levels were assessed using inductively coupled plasma mass-spectrometry. Overweight pregnant women had significantly reduced Cr (- 24%; p = 0.047) and Zn (- 13%; p = 0.008) content, as well as elevated hair Na and K levels as compared to the controls. Children from overweight and obese mothers had lower hair Mo (- 18%; p = 0.017), Se (- 8%; p = 0.043), and V (- 24%; p = 0.028) levels, as well as elevated Sr content (19%; p = 0.025). Correlation analysis revealed a significant relationship between maternal and child hair levels of Co (r = 0.170; p = 0.038), Cu (r = 0.513; p < 0.001), Mn (r = 0.240; p = 0.003), and Na (r = 0.181; p = 0.027) in the whole sample. Pre-pregnancy maternal body mass index (BMI) positively correlated with maternal hair K (r = 0.336; p < 0.001) and Na (r = 0.212; p = 0.008) and negatively correlated with V (r = - 0.204; p = 0.011) and Zn (r = - 0.162; p = 0.045) levels. The results indicate that impaired trace element and mineral metabolism may play a role in the link between maternal obesity, complications of pregnancy and child's postnatal development. Hypothetically, dietary improvement may be used as a tool to reduce these risks. However, further experimental and clinical studies are required to investigate the relationship between obesity and trace element metabolism in pregnancy

The impact of lifestyle factors on age-related differences in hair trace element content in pregnant women in the third trimester

BACKGROUND: Trace elements play a significant role in the regulation of human reproduction, while advanced age may have a significant impact on trace element metabolism. The objective of the present study was to assess the impact of lifestyle factors on age-related differences in hair trace element content in pregnant women in the third trimester. METHODS: A total of 124 pregnant women aged 20&ndash;29 (n = 72) and 30&ndash;39 (n = 52) were ex- amined. Scalp hair trace element content was assessed using inductively coupled plasma mass spectrometry at NexION 300D (Perkin Elmer, USA) after microwave digestion. RESULTS: The results showed that the elder pregnant women had 36% (p = 0.009), 14% (p = 0.045), and 45% (p = 0.044) lower hair Zn, V, and Cd content, and 16% (p = 0.044) higher hair B levels &ndash; in comparison to the respective younger group values. Multiple regression analysis demonstrated that the age of the women had a significant influence on hair V and Zn levels. B content was also significantly influenced by age at first intercourse, smoking status, and specific dietary habits. None of the lifestyle factors were associated with hair Cd content in pregnant women. Hair V levels were also affected by following a special diet. Interestingly, alcohol intake did not have a significant impact on hair trace element content. CONCLUSIONS: These data indicate that lifestyle factors have a significant influence on age-related changes in hair trace elements during pregnancy that may impact the outcome of pregnancy