307 research outputs found
Influence of summer temperatures on basic economic and tourism indicators of the middle mediterranean
The Middle Mediterranean is characterized by long, hot, and dry summers, significant historical and cultural values, and the warm Mediterranean sea, making it attractive for coastal tourism. Given these characteristics, the goal of our paper is to analyze the influence of summer temperatures in the region of the Middle Mediterranean on the values of underlying economic and tourism indicators. The method of simple linear correlation and regression was used. Based on the results of testing, we came to the conclusion that the temperatures in the summer months have no significant influence on selected economic and tourism indicators. Also, we conclude that social factors have the greatest influence on these indicators. The coefficients of variation are calculated in the observed period to analyze the variability of the tested values. It could not be identified a statistically significant relationship of indicators with summer temperatures
Hygienic substantiation of calculating models for predicting toxicity of different classes insecticides (first part).
This work is the first part of our study to develop alternative experimental mathematic models for predicting toxicity of insecticides. In the first stage, calculations will be carried out and the most reliable models will be proposed. In the second – a statistical analysis and comparative estimation of the toxicometric parameters obtained experimentally and calculated according to the proposed equations. The purpose of the research is the scientific substantiation of the calculation models for predicting toxicity of insecticides of different classes. Data on the physico-chemical properties and toxicometry parameters of fungicides are taken from the PPDB pesticides database. Insecticides of such chemical classes as derivatives of tetram and tetronic acids, benzoylureas, carbamates, neonicotinoids, pyrethroids, organophosphorus compounds, avermectins were selected for analysis. It has been established that there is a significant positive correlation between NO(A)EL in the chronic experiment of all insecticides, the median lethal doses at oral administration (LD50 per os) of pyrithoids and neonicotinoids, and the molecular weight (at p<0.05). There is a significant negative correlation between the toxicometry parameters of all insecticides and their individual groups (pyrithoids, neonicotinoids, organophosphorus compounds) and melting temperature and the octanol-water partition coefficient, log Po/w (at p<0.05). It is proved that the proposed calculation models for predicting insecticide hazards are adequate according to Fisher's criterion, and the coefficients of regression equations are reliable according to Student's criterion (p<0,05)
Endothelial dysfunction in adolescents with arterial hypertension: results of rheovasographic evaluation and heart rate variability analysis
Background As a major regulator of local vascular
homeostasis, the endothelium maintains vascular tone
through the balance between vasodilatation and vasoconstriction.
Upsetting this tight balance leads to endothelial
dysfunction . The latter is thought to be a marker of future
cardiovascular events in hypertensive patients.
The purpose of this research was to assess endothelial vasomotor
function with relation to heart rate variability in
adolescents with arterial hypertension.
Material and methods 56 adolescents (33 males, 23 females,
aged 22 ± 2 years) were subdivided into equal
groups (regarding gender, age, body mass index and genetic
burden) according to hypertension appearance and
smoking habits. All of them underwent forearm
rheovasography with measurements of reactive hyperemia
test heart rate variability being taken (a five-minute recording).
As reliable values for evaluating endothelial function,
relative changes in the peak blood flow velocity (DdZ/
/dT) and pulse blood volume (DdV) at the 1st min after
reperfusion were used. The following parameters of the
time (RRNN, SDNN, RMSSD, pNN50, CV) and frequency
(TP, VLF, LF, HF; LF/HF) domain analysis were
used for assessing heart rate modulation. Results Our analysis elicited a significant difference in both
velocity and volume characteristics between hypertensive
smokers and healthy individuals. Endothelial function in
hypertensive non-smoking patients and normotensive smokers
was also impaired. Heart rate variability was decreased
and sympathetic tone prevailed in hypertensive adolescents.
Both are associated with endothelial dysfunction.
Conclusions Endothelial function is likely to be impaired
in hypertensive adolescents, particularly among those who
smoke. Moreover, heart rate variability is decreased and
sympathetic tone prevails with relation to endothelial dysfunction
towards the autonomic imbalance
Transient and sustained afterdepolarizations in accessory olfactory bulb mitral cells are mediated by distinct mechanisms that are differentially regulated by neuromodulators
Social interactions between mammalian conspecifics rely heavily on molecular communication via the main and accessory olfactory systems. These two chemosensory systems show high similarity in the organization of information flow along their early stages: social chemical cues are detected by the sensory neurons of the main olfactory epithelium and the vomeronasal organ. These neurons then convey sensory information to the main (MOB) and accessory (AOB) olfactory bulbs, respectively, where they synapse upon mitral cells that project to higher brain areas. Yet, the functional difference between these two
Generation of electromagnetic fields of extremely high intensity by coherent summation of Cherenkov superradiance pulses
We demonstrate both theoretically and experimentally the possibility of correlating the phase of a Cherenkov superradiance (SR) pulse to the sharp edge of a current pulse, when spontaneous emission of the electron bunch edge serves as the seed for SR processes. By division of the driving voltage pulse across several parallel channels equipped with independent cathodes we can synchronize several SR sources to arrange a two-dimensional array. In the experiments carried out, coherent summation of radiation from four independent 8-mm wavelength band SR generators with peak power 600 MW results in the interference maximum of the directional diagram with an intensity that is equivalent to radiation from a single source with a power of 10 GW
Experimental observation of superradiance in millimeter-wave band
The first experimental results of the observation of superradiance from a single subnanosecond electron bunch are presented. Superradiance was associated with different varieties of stimulated emission (bremstruhlung, cyclotron, Cherenkov, etc). Unique megawatt power level microwave pulses of short duration (0.3-0.5 ns) have been obtained
Coherent summation of emission from relativistic Cherenkov sources as a way of production of extremely high-intensity microwave pulses
For relativistic Cherenkov devices, we investigate the process of high-power microwave pulse generation with its phase correlating to the sharp edge of an e-beam current pulse. Our theoretical consideration is referred to quasi-stationary and superradiative (SR) generation regimes when spontaneous emission of the e-beam edge serves as the seed for the development of further coherent oscillations. Phase correlation of the excited microwave pulses with the characteristics of the current pulse front and/or an initial external electromagnetic pulse has been additionally confirmed by particle-in-cell simulations. Pulse-to-pulse stability of the radiation phase within several percents of the oscillation period makes it possible to arrange multichannel schemes producing mutually coherent microwave pulses. In the experiments that have been carried out, the cathodes of independent generators were powered by identical accelerating pulses from strictly synchronized voltage modulators, or by splitting the pulse from a single powerful modulator. For the 2-ns regime with the power of each Ka-band backward-wave oscillator about 100 MW, we demonstrate quadratic growth of the power density in the interference maximum of the directional diagram. In a short pulse SR regime, with the peak power of 600 MW in a single channel, for a four-channel 2-D array, we attained a 16-fold radiation intensity gain
СТРАТЕГИЯ И МЕХАНИЗМЫ ОБЕСПЕЧЕНИЯ НАЦИОНАЛЬНОЙ ПРОДОВОЛЬСТВЕННОЙ БЕЗОПАСНОСТИ РЕСПУБЛИКИ БЕЛАРУСЬ
Currently the Republic of Belarus is entering a new level of solving problems in the field of national food security. It is required to maintain a high level of self-sufficiency, to create conditions for improving population nutrition quality, to ensure demand for Belarusian products in foreign markets, integration into the world market, etc. The article presents conceptual provisions, goals and objectives of the long-term strategy of the Republic of Belarus in the field of food security, and also analyzes the mechanisms for their implementation. These provisions form the basis of the Doctrine of National Food Security of the Republic of Belarus till 2030, which is to provide a fundamental basis for improving the welfare of population and availability of quality food for healthy nutrition and healthy lifestyle based on sustainable competitive agricultural production and creation of favorable social and economic conditions. The results of monitoring of the national food security in 2016 are presented, significant trends and factors of physical and economic accessibility of food products are identified. Mechanisms for achieving the goals and objectives of the national food security development are proposed, including mechanism for identifying, assessing and anticipating threats, regulatory support, as well as management and regulation ensuring implementation of target criteria at the national, regional and local levels. Implementation of the obtained results will allow to create stable prerequisites for the development of agro-industrial complex in the conditions of unstable external environment conditions, to strengthen food security and independence of the country.В настоящее время Республика Беларусь выходит на новый уровень решения задач в сфере национальной продовольственной безопасности. Требуется сохранить высокий уровень самообеспечения, создать условия для повышения качества питания населения, обеспечить востребовательность белорусской продукции на внешних рынках, интеграцию в мировой рынок и др. В статье представлены концептуальные положения, цели и задачи долгосрочной стратегии Республики Беларусь в области обеспечения продовольственной безопасности, а также проанализированы механизмы их реализации. Указанные положения составляют основу Доктрины национальной продовольственной безопасности Республики Беларусь до 2030 года (проект), которая призвана сформировать фундаментальную основу для повышения обеспеченности населения и доступности качественного продовольствия для полноценного питания и здорового образа жизни на основе устойчивого конкурентоспособного аграрного производства и создания благоприятных социально-экономических условий. Представлены результаты мониторинга национальной продовольственной безопасности по итогам 2016 г., определены значимые тенденции и факторы доступности продуктов питания. Предложены механизмы достижения целей и задач развития национальной продовольственной безопасности, включая механизм выявления, оценки и упреждения угроз, нормативно-правового обеспечения, а также управления и регулирования, обеспечивающий выполнение целевых критериев на национальном, региональном и местном уровнях. Внедрение полученных результатов позволит создать устойчивые предпосылки развития АПК в условиях нестабильной конъюнктуры внешней среды, укрепить продовольственную безопасность и независимость страны.
Experience of using MRT imaging in specifying diagnosis of obstructive diseases of the biliopancreatoduodenal zone.
The article presents the experience of surgical treatment of 12 patients with pancreatic cancer who were treated at the clinic of the Department of Surgery No. 2 of the ONMEDU during 2017. As a preoperative diagnosis, an MRI scan was performed in these patients. In general, the intraoperative size of the tumor was not significantly different from MRI - sizes: the medians of their differences were only + 5.5 mm and + 3.5 mm for the average and maximum MRT sizes. The calculated sensitivity and specificity of the method of MRTand CT in the assessment of artery invasion was 83.3% and 71.4% respectively, in the assessment of vein invasion - up to 50.0% and 42.9%, respectively. The combination of MRI and CT with intravenous contrast is the best option for planning surgical tactics today
Experience of using MRT imaging in specifying diagnosis of obstructive diseases of the biliopancreatoduodenal zone.
The article presents the experience of surgical treatment of 12 patients with pancreatic cancer who were treated at the clinic of the Department of Surgery No. 2 of the ONMEDU during 2017. As a preoperative diagnosis, an MRI scan was performed in these patients. In general, the intraoperative size of the tumor was not significantly different from MRI - sizes: the medians of their differences were only + 5.5 mm and + 3.5 mm for the average and maximum MRT sizes. The calculated sensitivity and specificity of the method of MRTand CT in the assessment of artery invasion was 83.3% and 71.4% respectively, in the assessment of vein invasion - up to 50.0% and 42.9%, respectively. The combination of MRI and CT with intravenous contrast is the best option for planning surgical tactics today
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