Isolated ionospheric disturbances as deduced from global GPS network

International audienceWe investigate an unusual class of medium-scale traveling ionospheric disturbances of the nonwave type, isolated ionospheric disturbances (IIDs) that manifest themselves in total electron content (TEC) variations in the form of single aperiodic negative TEC disturbances of a duration of about 10min (the total electron content spikes, TECS). The data were obtained using the technology of global detection of ionospheric disturbances using measurements of TEC variations from a global network of receivers of the GPS. For the first time, we present the TECS morphology for 170 days in 1998?2001. The total number of TEC series, with a duration of each series of about 2.3h (2h18m), exceeded 850000. It was found that TECS are observed in no more than 1?2% of the total number of TEC series mainly in the nighttime in the spring and autumn periods. The TECS amplitude exceeds the mean value of the "background" TEC variation amplitude by a factor of 5?10 as a minimum. TECS represent a local phenomenon with a typical radius of spatial correlation not larger than 500km. The IID-induced TEC variations are similar in their amplitude, form and duration to the TEC response to shock-acoustic waves (SAW) generated during rocket launchings and earthquakes. However, the IID propagation velocity is less than the SAW velocity (800?1000m/s) and are most likely to correspond to the velocity of background medium-scale acoustic-gravity waves, on the order of 100?200m/s. Key words. Ionosphere (ionospheric irregularities, instruments and techniques) - Radio science (ionospheric propagation

Actual problems of increased efficiency of use of the region's resource potential

This article defines the current trends and discloses regularities connected with integration management of the competitiveness reserves system for the food complex enterprises. The study presents in detail the main financial indicators relating to economic activity of the leading enterprises of the Republic of Tatarstan territorial production complexes. In the course of the analysis, an unstable dynamics of the domestic enterprises' development was revealed; on results of the study we drew a conclusion and gave recommendations regarding the economic efficiency of the business processes management. At the present development stage of the market relations the enterprise's senior management needs to monitor the current market and to solve constantly the problems associated with increased competitive advantages for organizing sustainable enterprise development. In order to manage effectively the modern business processes now, it is necessary to have a deep knowledge of the market situation and possibility to respond flexibly to the rapidly varying market changes. The competitiveness reserves and factors of the region's food complex were systematized. According to the following classification features, various factors were presented in the work: short-, medium-, long-term, by management and content in projects and programs, by period and content of the problems to be solved

Arctic sea ice area changes in CMIP3 and CMIP5 climate models’ ensembles

The shrinking Arctic sea ice cover observed during the last decades is probably the clearest manifestation of ongoing climate change. While climate models in general reproduce the sea ice retreat in the Arctic during the 20th century and simulate further sea ice area loss during the 21st century in response to anthropogenic forcing, the models suffer from large biases and the results exhibit considerable spread. Here, we compare results from the two last generations of climate models, CMIP3 and CMIP5, with respect to total and regional Arctic sea ice change. Different characteristics of sea ice area (SIA) in March and September have been analysed for the Entire Arctic, Central Arctic and Barents Sea. Further, the sensitivity of SIA to changes in Northern Hemisphere (NH) temperature is investigated and dynamical links between SIA and some atmospheric variability modes are assessed. CMIP3 (SRES A1B) and CMIP5 (RCP8.5) models not only simulate a coherent decline of the Arctic SIA but also depict consistent changes in the SIA seasonal cycle. The spatial patterns of SIC variability improve in CMIP5 ensemble, most noticeably in summer when compared to HadISST1 data. A better simulation of summer SIA in the Entire Arctic by CMIP5 models is accompanied by a slightly increased bias for winter season in comparison to CMIP3 ensemble. SIA in the Barents Sea is strongly overestimated by the majority of CMIP3 and CMIP5 models, and projected SIA changes are characterized by a high uncertainty. Both CMIP ensembles depict a significant link between the SIA and NH temperature changes indicating that a part of inter-ensemble SIA spread comes from different temperature sensitivity to anthropogenic forcing. The results suggest that, in general, a sensitivity of SIA to external forcing is enhanced in CMIP5 models. Arctic SIA interannual variability in the end of the 20th century is on average well simulated by both ensembles. To the end of the 21st century, September variability is strongly reduced in CMIP5 models under RCP8.5 scenario, whereas variability changes in CMIP3 and in both ensembles in March are relatively small. The majority of models in both CMIP ensembles demonstrate an ability to capture a negative correlation of interannual SIA variations in the Barents Sea with North Atlantic Oscillation and sea level pressure gradient in the western Barents Sea opening serving as an index of oceanic inflow to the Sea

Изменения площади арктических морских льдов в ансамблях климатических моделей CMIP3 и CMIP5

The shrinking Arctic sea ice cover observed during the last decades is probably the clearest manifestation of ongoing climate change. While climate models in general reproduce the sea ice retreat in the Arctic during the 20th century and simulate further sea ice area loss during the 21st century in response to anthropogenic forcing, the models suffer from large biases and the results exhibit considerable spread. Here, we compare results from the two last generations of climate models, CMIP3 and CMIP5, with respect to total and regional Arctic sea ice change. Different characteristics of sea ice area (SIA) in March and September have been analysed for the Entire Arctic, Central Arctic and Barents Sea. Further, the sensitivity of SIA to changes in Northern Hemisphere (NH) temperature is investigated and dynamical links between SIA and some atmospheric variability modes are assessed.CMIP3 (SRES A1B) and CMIP5 (RCP8.5) models not only simulate a coherent decline of the Arctic SIA but also depict consistent changes in the SIA seasonal cycle. The spatial patterns of SIC variability improve in CMIP5 ensemble, most noticeably in summer when compared to HadISST1 data. A better simulation of summer SIA in the Entire Arctic by CMIP5 models is accompanied by a slightly increased bias for winter season in comparison to CMIP3 ensemble. SIA in the Barents Sea is strongly overestimated by the majority of CMIP3 and CMIP5 models, and projected SIA changes are characterized by a high uncertainty. Both CMIP ensembles depict a significant link between the SIA and NH temperature changes indicating that a part of inter-ensemble SIA spread comes from different temperature sensitivity to anthropogenic forcing. The results suggest that, in general, a sensitivity of SIA to external forcing is enhanced in CMIP5 models. Arctic SIA interannual variability in the end of the 20th century is on average well simulated by both ensembles. To the end of the 21st century, September variability is strongly reduced in CMIP5 models under RCP8.5 scenario, whereas variability changes in CMIP3 and in both ensembles in March are relatively small. The majority of models in both CMIP ensembles demonstrate an ability to capture a negative correlation of interannual SIA variations in the Barents Sea with North Atlantic Oscillation and sea level pressure gradient in the western Barents Sea opening serving as an index of oceanic inflow to the Sea.Сокращение площади арктических морских льдов в течение последних десятилетий служит, пожалуй, самым ярким проявлением изменений климата. Хотя глобальные модели климата в целом воспроизводят уменьшение площади морских льдов в Арктике во второй половине XX в. и предсказывают сокращение этой площади в XXI  в. при заданных сценариях антропогенного воздействия, результаты моделей характеризуются значительным разбросом и систематическими ошибками. В работе сравниваются результаты моделирования площади морских льдов в Арктике двумя последними поколениями глобальных климатических моделей CMIP3 и CMIP5 в XX и XXI вв. Рассматриваются различные характеристики площади льдов в марте и сентябре для всей Арктики, Центральной Арктики и Баренцева моря. Также анализируются чувствительность площади морских льдов к изменению приземной температуры в Северном полушарии и связь вариаций этой площади с некоторыми модами атмосферной циркуляции

Side Chain Hydrophobicity Modulates Therapeutic Activity and Membrane Selectivity of Antimicrobial Peptide Mastoparan-X

The discovery of new anti-infective compounds is stagnating and multi-resistant bacteria continue to emerge, threatening to end the "antibiotic era". Antimicrobial peptides (AMPs) and lipo-peptides such as daptomycin offer themselves as a new potential class of antibiotics; however, further optimization is needed if AMPs are to find broad use as antibiotics. In the present work, eight analogues of mastoparan-X (MPX) were investigated, having side chain modifications in position 1, 8 and 14 to modulate peptide hydrophobicity. The self-association properties of the peptides were characterized, and the peptide-membrane interactions in model membranes were compared with the bactericidal and haemolytic properties. Alanine substitution at position 1 and 14 resulted in higher target selectivity (red blood cells versus bacteria), but also decreased bactericidal potency. For these analogues, the gain in target selectivity correlated to biophysical parameters showing an increased effective charge and reduction in the partitioning coefficient for membrane insertion. Introduction of an unnatural amino acid, with an octyl side chain by amino acid substitution, at positions 1, 8 and 14 resulted in increased bactericidal potency at the expense of radically reduced membrane target selectivity. Overall, optimized membrane selectivity or bactericidal potency was achieved by changes in side chain hydrophobicity of MPX. However, enhanced potency was achieved at the expense of selectivity and vice versa in all cases

NEW NUTRIENT MEDIUM ON THE BASIS OF DRY FIBRIN HYDROLYSATE FOR V. CHOLERAE CULTIVATION

The data on exploration of biological properties of experimental solid and liquid media on the basis of dry enzymatic hydrolysate of fibrinobtained from production waste of anti-rabies immunoglobulin is presened here. The culture media engineered meets the requirements of normative documents and. is highly competitive with the test medium in their qualitative characteristics. Suggested media can be used for V. cholerae cultivation, including submerged cultivation, in production of cholera preventive and. diagnostic preparations