Current trends in global demographic processes

Current local and national demographic trends have deepened the existing and formed new global demographic processes that have received a new historical reasoning that requires deep scientific research taking into account the influence of the multifactorial global dimension of the modern society development. The purpose of the article is to study the development of global demographic processes and to define the causes of their occurrence, manifestations, implications and prospects for implementation in the first half of the 21st century. The authors have identified and characterized four global demographic processes, namely population growth, migration, increase of tourism, and change in population structure. It is projected that in the 30’s of the 21st century, the number and growth rates of the world population will reach the objective growth and these dynamics over the next two decades will begin to change in the direction of reducing the growth rates, which will lead to gradual stabilization, and eventually reduce the size of the world population. By the middle of the 21st century, one can observe the preservation of the growth rates of international and domestic migration, the growth of international migration flows from the South to the North and from the East to the West, the strengthening of new economically developed centers of gravity (Canada, Australia and New Zealand), the increase in migration of rural population to cities, as well as urbanization and activation of the metropolises development. The share of international tourists in comparison with the world population will be constantly increasing, and the annual growth rate of the number of international tourists will significantly depend on the world economy and may vary at the several percent level. Permanent change will occur in the age, religious-cultural and socio-economic structure of the population

РАЗРАБОТКА КОМПЬЮТЕРНОЙ МОДЕЛИ ГЕРМАНИЕВОГО ДЕТЕКТОРА И ПОЛУЧЕНИЕ МОДЕЛЬНЫХ СПЕКТРОВ СТАНДАРТНЫХ ОБРАЗЦОВ УРАНА U3O8 SRM-969

Computer modeling was carried out for gamma-ray spectra of nuclear materials, which were measured by using a semiconductor high-purity germanium detector ORTEC GEM25P4-70. The standard SRM-969 samples were used as sources of gamma radiation, which are cylindrical tanks of fixed volume, made of aluminum alloy 6061, filled with a dispersed uranium oxide powder (U3O8) with different concentrations of 235U. The products from radioactive decay chains are determined for uranium isotopes 235U and 238U, which give the main contribution to the gamma spectrum of uranium oxide (U3O8). A technique that makes it possible to compare the results of measurements with model spectra is developed. The correlation of the measured spectra to the model spectra was made by comparing the areas of the total absorption peaks for energies of 185 keV and 1001 keV, which are often used in gamma spectrometry to determine uranium enrichment. The selected parameters of the model and the source of the detector allowed to describe the measured gamma-ray spectra with an accuracy of better than 6 % at the total areas of the absorption peaks in the energy range 150–1100 keV. The developed model makes it possible to obtain the model of gamma spectra of various fissile materials, provided that there are the data available about the isotopic composition, the quantum yield of gamma lines for each isotope, and the activity of fissile material. These model spectra can be used for the development of measurement techniques and software testing in the field of nuclear spectroscopy. Проведено компьютерное моделирование гамма-спектров ядерных материалов, измеренных при помощи полупроводникового детектора из особо чистого германия ORTEC GEM25P4-70. В качестве источников гамма-излучения использовались стандартные образцы SRM-969, представляющие собой цилиндрические емкости фиксированного объема, выполненные из алюминиевого сплава (aluminum alloy 6061), заполненные мелкодисперсным порошком оксида урана (U3O8) с различной концентрацией 235U. Определены продукты распада из цепочек радиоактивных превращений изотопов урана 235U и 238U, которые дают наибольший вклад в гамма-спектр оксида урана (U3O8). Разработана методика, позволяющая сопоставить результаты измерений с модельными спектрами. Соответствие измеренных спектров модельным спектрам производилось путем сравнения площадей пиков полного поглощения для энергий 185 и 1001 кэВ, наиболее часто используемых в гамма-спектрометрии для определения обогащения урана. Выбранные параметры модели детектора и источника позволили описать измеренные гамма-спектры с погрешностью не хуже 6 % в площадях пиков полного поглощения в энергетическом диапазоне 150–1100 кэВ. Разработанная модель позволяет получить модельные гамма-спектры различных делящихся материалов при условии наличия сведений об изотопном составе, квантовом выходе гамма-линий для каждого изотопа, активности делящегося материала. Данные модельные спектры могут быть использованы при разработке методик выполнения измерений и тестировании программного обеспечения в области ядерной спектроскопии. Наиболее вероятное применение компьютерной модели – получение модельных спектров для контроля обогащения ядерного топлива и математическая калибровка гамма-спектрометра для неразрушающего анализа ядерных материалов различных конструкций и различного химического и изотопного состава.

The Fruit Flies (Diptera, Tephritidae) in Bhutan: New Faunistic Records and Compendium of Fauna

Based on a field survey from 2017, twenty-three species are reported from Bhutan for the first time: Acroceratitis ceratitina, A. hardyi, Anomoia approximata, Bactrocera connecta, B. latifrons, B. nigrifacia, B. syzygii, Campiglossa sororcula, Cecidochares connexa, Dacus jacobi, Gastrozona fasciventris, Hoplandromyia antelopa, Lenitovena ultima, Ptilona confinis, Rioxoptilona dunlopi, R. formosana, R. vaga, Spathulina acroleuca, Themara yunnana, Trypeta indica, Zeugodacus apiciflavus, Z. diversus, and Z. fereuncinatus. Four species of the genera Cornutrypeta, Hemilea, Morinowotome, and Vidalia are also recorded for the first time, but the precise determination to species needs additional study and material. As the result, 71 species is listed from Bhutan by far. Their taxonomic position and key characters are discussed. Illustrations for most of the newly recorded species are given

Comprehensive inventory of true flies (Diptera) at a tropical site

Peer reviewe

Comprehensive inventory of true flies (Diptera) at a tropical site

Estimations of tropical insect diversity generally suffer from lack of known groups or faunas against which extrapolations can be made, and have seriously underestimated the diversity of some taxa. Here we report the intensive inventory of a four-hectare tropical cloud forest in Costa Rica for one year, which yielded 4332 species of Diptera, providing the first verifiable basis for diversity of a major group of insects at a single site in the tropics. In total 73 families were present, all of which were studied to the species level, providing potentially complete coverage of all families of the order likely to be present at the site. Even so, extrapolations based on our data indicate that with further sampling, the actual total for the site could be closer to 8000 species. Efforts to completely sample a site, although resource-intensive and time-consuming, are needed to better ground estimations of world biodiversity based on limited sampling