Age Composition Of Population Research Articles

Incidence and mortality of endometrial cancer in China, data from China Cancer Registry Annual Report, 2004-2017

Objective: To analysis the incidence rate and mortality rate of endometrial cancer in China from 2004 to 2017 according to the data from China Cancer Registry Annual Report. Methods: The incidence and mortality data of endometrial cancer were extracted from the China Cancer Registry Annual Report 2004 to 2017, and the incidence, mortality, number of new cases, number of deaths were extracted according to the region (national, urban, rural and eastern, middle and western areas) and the age composition of population to estimate the incidence and mortality of endometrial cancer nationwide. The age-standardized incidence rate and mortality rate were calculated based on the Chinese standard population in 2000 (ASIRC, ASIRW) and Segi's world population (ASMRC, ASMRW). Join Point regression was used to calculate the annual percentage change of morbidity rate, and Cochran-Armitage trend test was used to analyze the changing trend of morbidity and mortality. Results: From 2004 to 2017, the number of women covered by the China Cancer Registry Annual Report has increased from 35 571 657 to 215 201 995, and the total population of the covered areas has increased from 5.53% to 31.39%. The crude incidence rate of endometrial cancer increased from 6.20/100 000 to 10.06/100 000, and showed an upward trend over time (P<0.001). After adjusting for age, ASIRC increased from 5.75/100 000 in 2004 to 6.79/100 000 in 2017, and ASIRW increased from 5.60/100 000 in 2004 to 6.56/100 000 in 2017, both showing an upward trend over time (all P<0.001). The crude incidence rates in urban area and rural area were respectively 10.89/100 000 and 9.25/100 000 in 2017, and the ASIRC was higher in urban than rural areas (7.14/100 000 vs 6.43/100 000) after adjusting for age. The ASIRW was higher in eastern areas than middle areas and western areas (7.16/100 000 vs 6.44/100 000 vs 5.60/100 000). The incidence rate in rural areas showed more significant growth than urban areas [annual percent change (APC): 3.2% vs 0.7%, P<0.001]. The age-specific incidence rate increased with age and reached a peak in the age group of 50-54 years (25.70/100 000). Incidence rate in the under-40 age group increased more in rural areas than in urban areas (69.84% vs-7.09%). From 2004 to 2017, the age-standardized mortality rate shows a decreasing trend, with the ASMRC from 1.83/100 000 to 1.47/100 000, and the ASMRW from 1.81/100, 000 to 1.46/100, 000. There was no significant difference between urban and rural areas in mortality of endometrial cancer. Age-specific mortality rates increased with age, reaching a peak in the age group 85 years and older (13.16/100 000). Conclusions: Recent years, there was an increasing incidence rate of endometrial cancer in China. Especially in rural areas, the incidence rate of endometrial cancer is increasing rapidly in young women under 40 years of age. There were differences between urban and rural areas and regions in the incidence rate of endometrial cancer. The incidence rates of endometrial cancer in some high-income cities have occupied the first place of female reproductive system malignant cancers. The age-standardized mortality rate of endometrial cancer shows a decreasing trend.

Bats (Chiroptera, Vespertilionidae) of the Bashkiria National Park

In 2018, 2019, 2021 and 2022 in the national park “Bashkiria” located in the southeastern part of the Republic of Bashkortostan, studies of the local fauna of bats (Mammalia: Chiroptera) were carried out. The uniqueness of the specially protected natural area lies in the presence of linden-maple-oak forests located on the eastern border of their range and a wide variety of surface and deep relief forms associated with the development of karst rocks. As a result, data on the habitation of 12 species of bats, which belong to six genera of the Vespertilionidae family, were obtained. Of these, eight species are included in the regional Red Book. The species Nyctalus lasiopterus, listed in the Red Book of the Russian Federation, was found in the Republic of Bashkortostan for the fi rst time. A cadastre is presented with a description of the places of work, geographical coordinates and results of catches, information on wintering places, the nature of stay in the region, reproduction, age and sex composition of populations, indicators of relative abundance. According to traps, the most numerous in the national park are: Pipistrellus nathusii, Vespertilio murinus, Myotis brandtii, Nyctalus noctula, M. daubentonii and Plecotus auritus. Few species are: Eptesicus nilssonii, M. mystacinus, N. leisleri and M. dasycneme, while M. nattereri and N. lasiopterus are rare. In addition to the identifi ed species, Pipistrellus pygmaeus, discovered by us 30 km south of the borders of the national park, can live on the territory. Recommendations on the protection of bats and the introduction of N. lasiopterus into the Red Book of the Republic of Bashkortostan are presented.

Long-term remote monitoring of the rookery of Eumetopias jubatus (Pinnipedia, Otariidae) on Matykil Island in the Magadan State Nature Reserve (Russia)

The severe decline in the number of Eumetopias jubatus (hereinafter – Steller sea lion) almost throughout the entire range has drawn the public attention to monitor the abundance and increase in research activity of the species. In Russia, such a study has been conducted regularly since the early 2000s. It includes range-wide population surveys in the Russian Far East, marking newborn pups and monitoring their survival, movements, and reproduction success. In the first decade of the XXI century, observers conducted direct observations on rookeries during the breeding season. Since 2011 a novel survey method has been used, using custom-made autonomous high-resolution remote cameras, which have been taking images of the rookeries all year round. In 2013, six remote-camera units were installed in the Magadan State Nature Reserve (Russia) at the rookery of the Steller sea lion located on Matykil Island. The cameras gathered images during day time every 5–30 min. Maintenance of the photo recorders was carried out once per year in the summer period. A total of 721 927 photographs were collected during eight years of the surveys. Of them, 60 632 photographs were manually analysed in this research. It was found that the Steller sea lions use the rookery throughout the year, with the exception of March when a dense and wide ice cover in the study area prevents the Steller sea lions from reaching the shore of Matykil Island. During the year, two peaks of the Steller sea lion population abundance were observed, namely summer and, with a higher number of individuals, in autumn. In summer, females predominate on the rookery, while in the autumn-winter period, young animals (mainly males) and mature (8+ years) adults. In winter, the number of Steller sea lions was low on the shore. We have seen branded Steller sea lions on Matykil Island from all rookeries in the Russian Far East, with the exception of animals born on the Commander Islands. The highest number of migrant Steller sea lions appears in the autumn period, and it is represented mainly by young animals (1–3 years old) and semi-adults (males aged 4–7 years). In general, the data obtained from images collected by remote cameras during the entire year provided a detailed picture of the rookery used by Steller sea lions during the entire annual cycle of their life and monitored the seasonal population dynamics, the sex and age composition of animals on the shore, and the reproductive success of marked Steller sea lions. Currently, the use of autonomous remote cameras remains the only available method of year-round monitoring of the state and habitat use of hard-to-reach remote Steller sea lion’s rookeries.

Spatial Distribution, Size and Age Composition of Population of Mya japonica Jay, 1857 (Bivalvia: Myidae) in Peter the Great Bay, Sea of Japan

Spatial Distribution, Size and Age Composition of Population of Mya japonica Jay, 1857 (Bivalvia: Myidae) in Peter the Great Bay, Sea of Japan

Spatial Distribution, Size and Age Composition of Population of &lt;i&gt;Mya japonica&lt;/i&gt; Jay, 1857 (Bivalvia: Myidae) in Peter the Great Bay, Sea of Japan

In July–August 2022, the spatial distribution and the composition of local aggregations of the bivalve mollusc Mya japonica Jay, 1857 in the Vostok Bay (Peter the Great Bay of the Sea of Japan) were studied. M. japonica occurred almost throughout the entire bay in a wide range of depths from 0 to 22 m at water temperatures from –1.9 to 25°С and salinity from 0 to 34‰. M. japonica was the most abundant in the shallow areas of the bays, closed from the direct wave impact, where, at a depth of up to 4–5 m, the density of the mollusc reached 27 ind./m2, and the biomass was almost 4 kg/m2, which averaged 56% of the total macrozoobenthos biomass. With increasing depth and moving from the dead-end of the bay to the open sea, the abundance of M. japo-nica decreased by one or two orders of magnitude. Local settlements differed significantly in size and age composition, size-frequency distribution of molluscs, indicating the nature of the replenishment of the benthic population with juveniles, as well as the proportion of commercial size individuals, which ranged from 37 to 98%. The reasons for the revealed features of the distribution and structure of the population of M. japonica are discussed.

On age composition of dynamic heterogeneous populations

. Populations of items continuously manufactured and incepted into operation are characterized by the corresponding distribution of a random age at each instant of chronological time. In this study, we consider heterogeneous populations with lifetime distributions indexed by a frailty parameter. Two approaches to defining the age composition for the described populations are described and the corresponding stochastic comparisons are considered.

THE AVIAN SONG OVER TIME: VARIABILITY AND STABILITY

Information is reviewed on the dynamics of bird singing over time, analyzing the rate of change in individual and population repertoires, and considering the factors affecting the rate of such changes. The available data indicate very significant periods of persistence of vocal patterns (song types) in songbird populations. The rate of change in population and individual repertoires is higher in species with an unlimited period of imprinting a song compared to species with a fixed period. The population repertoire of song types in numerous populations inhabiting vast and continuous habitats is more stable than in small and isolated populations occupying structurally fragmented habitats. The most common vocal patterns are the most conserved from year to year, while rare variants often disappear from the population repertoire over time. Abnormal climatic phenomena that cause significant changes in the age composition of populations contribute to rapid changes of dialects. The cases of rapid synchronous changes in vocal repertoires in individuals in local populations, as well as in populations separated from each other by a great distance, are considered in detail. The causes that give rise to this need further research. The most likely reasons may be an exchange of vocal models at wintering grounds or the simultaneous introduction of a large number of migrants into the study populations, which in species with an open training period may cause changes in the repertoire of local individuals also borrowing new vocal models.

Improving the age composition of dynamic populations of manufactured items

Populations of manufactured degrading items that are incepted into operation with a given rate are considered. To improve the age composition of these dynamic populations, the truncation of items’ lifetimes is proposed and the corresponding optimization problem is studied. The impact of shocks on the population age structures is also described. The effect of these ‘interventions’ for dynamic and static populations has not been studied in the literature.

Management strategy of the naked carp (Gymnocypris przewalskii) in the Qinghai lake using matrix population modeling

Naked carp (Gymnocypris przewalskii) is the only fish species commercially harvested in Qinghai Lake, which is the largest inland saltwater lake in China. Multiple ecological stresses such as long-term overfishing, drying-up of riverine inflows, and decreases in spawning habitat caused the naked carp population to decrease from 320,000 tons before the 1950s to only 3000 tons by the early 2000s. We used matrix projection population modeling to quantitatively simulate the dynamics of the naked carp population from the 1950s to the 2020s. Five versions of the matrix model were developed from the field and laboratory information that represented different population states (high but declining, low abundance, very low abundance, initial recovery, pristine). Equilibrium analysis was applied to density-independent versions of the matrices and population growth rate, age composition, and elasticities were compared among versions. Stochastic, density-dependent version of the most recent decade (recovering) version was used to simulate the time-dependent responses to a range of levels of artificial reproduction (addition of age-1 from hatchery) and of the pristine version to simulate combinations of fishing rate and minimum age of harvest. Results showed the major role of overfishing in the population decline and that the population growth rate was most sensitive to the survival of juveniles and the spawning success of early-age adults. Dynamic simulations showed a rapid population response to artificial reproduction when population abundance was low and that if artificial reproduction continues at its current level, then population biomass would reach 75% of its pristine biomass after 50 years. Simulations with the pristine version identified sustainable fishing levels and the importance of protecting the first few ages of maturity. Overall, modeling results showed that artificial reproduction under conditions of no fishing is an effective approach to restoring the naked carp population. Further effectiveness should consider maximizing survival in the months just after release and maintaining genetic and phenotypic diversity. More information on density-dependent growth, survival, and reproduction, as well as on the genetic diversity and growth and migratory behavior (phenotypic variation) of released and native-spawned fish, would help inform management and conservation strategies and practices going forward.

Changes in human potential in Russia until 2050 under the influence of the transformation of the age structure of the population

The subject of the study is the projected changes in the age composition of the population as a factor of the prospective dynamics of the components of human potential. The purpose of the work is to assess the upcoming shifts in the age composition of the Russian population for the period up to 2050 and related changes in the health status of the population and the proportion of people with higher education as components of human potential. The article presents the results of the forecast calculation of the age population of Russia for the period up to 2050. As a result of the study, it was found out that a significant increase in the proportion of the elderly population is expected, a decrease in the proportion of people of working age and an even greater decrease in the proportion of the population under the age of 20. An assessment of possible changes in the health status of the population (according to self-assessment) in connection with the upcoming aging of the population is given. It is concluded that taking into account generational changes in the proportion of people with higher education, combined with upcoming shifts in the age structure of the population, indicate a likely significant increase in this indicator in the population of Russia in the next 30 years.

Conservation Biology of Endangered Wild Walnut in Tianshan Valley, Xinjiang

Wild walnut belongs to the walnut family in Tianshan Valley of Xinjiang. Tertiary tree species in Central Asia and endangered plant under state protection. Its main distribution areas are as far as the Western Tianshan Mountains and Pamir-Alai Mountains of the former Soviet Union, and it is only distributed in Dekuztala County of Xinjiang, China. It is of great scientific value to study the origin and evolution of cultivated walnut, paleofloristic changes, paleogeography, Tertiary and Quaternary climatic changes. Due to the narrow distribution of wild walnut in Xinjiang, harsh desert conditions, climate change, human disturbance, habitat fragmentation and other factors, wild walnut in Xinjiang is facing the risk of extinction, and it is urgent to carry out research on conservation biology and conservation genetics. In this paper, floristic, community and plant population research and analysis methods were adopted [1][6]. In this paper, the floristic composition, plant ecological type structure, plant climate and soil water characteristics of wild walnut community, age structure of wild walnut population, fluctuation cycle and evolution trend of population age composition, population growth characteristics, phenotypic plasticity of seeds and compound leaves, and biomass allocation were analyzed comprehensively in Xinjiang Nature Reserve. And put forward scientific protection countermeasures.

Геодемографическая классификация регионов Северо-Кавказского федерального округа

Introduction. The dynamics of the vital movement of the population of the North Caucasus for 2005-2020 is investigated. Research methods and materials. Both traditional and the latest geographic research methods are used - comparative geographical, spatial analysis, statistical, GIS technologies, population surveys, etc. Research results. The conducted studies have shown that despite the apparent well-being, a tense demographic situation is developing in the North Caucasus. Favorable demographic results are obtained only at the expense of three subjects - Dagestan, Ingushetia and Chechnya. In other regions, narrowed and negative reproduction is observed. The natural increase is getting lower and lower. The small generation born in the 1990s reached the fertile age. COVID-19 restrictions and a crisis in the economy have led to an even greater decline in the birth rate and an increase in mortality. The conducted geodemographic classification of the regions of the North Caucasus showed that the most favorable situation is observed in Ingushetia, the situation is slightly worse in Chechnya and Dagestan, narrowed reproduction in Kabardino-Balkaria and Karachay-Cherkessia and the most tense situation is in North Ossetia and the Stavropol Territory. Conclusion. To improve the situation, a differentiated approach is needed to different regions in the demographic sphere, the creation of new workplaces. The outflow of the able-bodied population from the regions of the North Caucasus leads to a violation of the population age composition and, thereby, undermines the fertility of the population. This leads to a decrease in the birth rate and, accordingly, natural increase. Resume. The article presents the results of studies of the natural movement of the population of Russia and the North Caucasus Federal District. At the same time, the multi-scale method of research and geodemographic classification was taken as the basis. It has been established that relatively favorable results on the scale of Russia were achieved in the North Caucasus Federal District, and on the scale of the North Caucasian Federal District - in Ingushetia, Chechnya and Dagestan. It was determined that along with the traditional factors of mortality, the factor of infectious morbidity began to play a significant role. It is shown that at the same time, mortality in working age has increased. It was revealed that there is a significant territorial differentiation of the natural movement of the population both in Russia as a whole and in the North Caucasus Federal District. The results of the research can be useful in developing programs for further demographic development of the regions.

The Impact of Socio-economic Factors on Fertility Behaviour: A Cross-country Analysis

International comparisons of fertility behaviour are based on two crucial assumptions. First, it is assumed that the response of fertility rates to socio-economic factors is similar across different age-cohorts of female population in the reproductive age-group. Second, it is assumed that country-specific effects do not influence the parameter estimates of the fertility model. Recent availability of cross-country data for a number of years allows us to pool data for more than 100 countries for the period 1955–1985 and estimate the fertility model. The results show that the impact of socio-economic factors differs across different age-cohorts; particularly, the negative impact of improvements in female status on the fertility rates is higher among the younger age-cohorts. Similarly, our results show that cross-country differences affect fertility rates significantly. However, the differences tend to diminish as countries become more developed. These results indicate that not only cross-country differences but also the changes in age-composition of female population should be taken into account in formulating the policies to control fertility and population growth. Furthermore, improvements in female literacy turn out to be the most effective tool to control population growth.

UNPARTNERED AND CHILDLESS OLDER ADULTS' RISK OF LONELINESS DURING COVID-19 BY COUNTRY CONTEXT

Abstract Older adults with non-traditional family structures (unpartnered and childless) may be at higher risk for loneliness. Yet, experiences of loneliness during COVID-19 can vary depending on a country’s context (e.g., culture, demography, COVID-19 mitigation policies, severity of the pandemic). We explore associations between older Europeans’ family structure and loneliness to assess risks for those with non-traditional family structures (e.g., unpartnered vs partnered, childless vs parents) during the pandemic across a variety of country contexts. We analyze data from the Survey of Health, Ageing and Retirement in Europe (SHARE) collected before (2019/2020) and twice during (2020, 2021) the pandemic to examine if unpartnered and childless older adults are at higher risk of loneliness, and compare results by multiple indicators of country context (fertility and partnership rates, stringency of COVID mitigation policies, population age composition, and COVID fatality rates). Results of this study can potentially inform current and future pandemic mitigation strategies.

Increased risk of out-of-hospital cardiac arrest in patients with congenital heart disease: a nationwide study

Abstract Background The last four decades witnessed substantial improvements in treatment of congenital heart disease (CHD) leading to most children surviving into adulthood. Currently, the number of adults with CHD surpasses that of children. The shift in the CHD population's age composition necessitates focusing on long-term problems. A significant, but not well-investigated, issue is the risk of out-of-hospital cardiac arrest (OHCA) in adults with CHD. Purpose To investigate overall and temporal changes in the rate of OHCA associated with CHD compared with the general population. Method We conducted a nested case-control study matching all adult patients with OHCA of presumed cardiac cause between 2001 and 2015 with up to five controls from the entire Danish population on age, sex, date of OHCA and cardiac comorbidities status (at least one among ischemic heart disease, heart failure and presence of implantable cardioverter-defibrillator). Patients with CHD were identified using in- and out-patient hospital diagnoses any time prior to OHCA and divided into two mutually exclusive subgroups, either non-severe or severe CHD. The subclassification of CHD is based on a hierarchical approach previously used, where at least one severe CHD diagnosis is required to be classified as severe. We used Cox regression models to compute hazard ratios (HRs) and 95% confidence intervals (CI) of OHCA. We stratified on CHD status (non-severe, severe or control), sex and OHCA year group (2001–2008 vs 2009–2015). Results We included 35,005 OHCA cases and 175,025 controls: the median age was 72 years, 66.9% were male and 34.6% had cardiac comorbidities. In total, among cases, we identified 103 patients with non-severe CHD and 51 with severe CHD, while, among controls, 247 with non-severe CHD and 69 with severe CHD. Both non-severe and severe CHD were overall associated with higher rates of OHCA compared with the general population: HR 2.11 (95% CI, 1.68–2.66) and HR 3.93 (95% CI, 2.71–5.69), respectively (Figure A). We found similar results when we stratified the analyses according to the presence of cardiac comorbidities at date of OHCA (Figure B) and sex. When stratified by OHCA year group, we observed stable rates of OHCA associated with non-severe CHD: from HR 2.03 (95% CI, 1.36–3.03) in the period 2001–2008 to HR 2.15 (95% CI, 1.62–2.86) in the period 2009–2015. Conversely, we observed a trend towards decreasing rates of OHCA associated with severe CHD: from HR 5.04 (95% CI, 2.79–9.11) in the period 2001–2008 to HR 3.10 (95% CI, 1.80–5.19) in the period 2009–2015 Conclusions Non-severe and severe CHD were both associated with higher rates of OHCA compared with the general population. While we observed decreasing rates of OHCA over calendar year for severe CHD, they remained stable for non-severe CHD. Funding Acknowledgement Type of funding sources: Public hospital(s). Main funding source(s): Gentofte University Hospital, Hellerup, Denmark

Variation in growth, length and age characteristics of estuarine Acanthopagrus (Sparidae) populations in New South Wales, Australia

Knowledge of spatial variation in growth and demographic characteristics of exploited teleost populations is informative for understanding levels of resilience and susceptibility to environmental and anthropogenic perturbations and for resource management. This study investigated variation in length- and age-compositions, length-at-age and growth, longevity and mortality of Acanthopagrus (A. australis, A. butcheri and their hybrids) population complexes across seven estuaries spanning seven degrees of latitude in eastern Australia. Populations were sampled using two gears according to standardised fishery-independent survey protocols. Populations within each estuary displayed considerable variation in length-at-age, with sex-specific growth attributes evident in some estuaries but not others. Nevertheless, females dominated populations, and on average, the mean lengths and ages of females were greater than males within each estuary population. Estuary type and location appeared to influence the estuary-specific growth characteristics of both sexes, with populations in the southern coastal lakes having, on average, greater mean lengths at age and faster growth than those in the northern riverine estuaries. Length and age compositions of populations did not vary accordingly, with observed longevities and estimated natural mortalities varying among estuaries, most likely reflecting estuary-specific environmental conditions and anthropogenic activities. In general, populations across all estuaries primarily comprised fish <25 cm fork length (FL) and 10 years of age. Given their potential to reach FLs up to 50 cm and ages >20 years, populations across most estuaries appeared length and age truncated. Ecological relationships and resource management implications are discussed.

The importance of reclassification to understanding urban growth: A demographic decomposition of the United States, 1990–2010

AbstractAn improved understanding of reclassification as a sociodemographic component of urban growth is important for urban planning and sustainable development. However, empirical assessments of the effect of reclassification on urban population dynamics are lacking, especially in countries in the later stage of the urban transition. Using recently available data on spatial reclassification of rural and urban land areas and population, and adopting multiregional demographic methods, we explicitly examine the effects of reclassification, natural growth and rural–urban migration on urban growth in the United States for the intercensal periods of 1990–2000 and 2000–2010. Results suggest that reclassification played a significant role in U.S. urban population change but its magnitude depends on assumptions about the timing of reclassification. The net effect of reclassification on urban change is the largest when reclassification is assumed to occur at the end, and the smallest when assumed to occur at the beginning, of the decennial census periods. While the impact of natural growth on U.S. urban population change is relatively stable, there is significant uncertainty in the effects of reclassification and rural–urban migration. Additionally, international migration is a key source of urban growth in the United States. We find that the places reclassified from rural to urban or from urban to rural experienced the largest changes in population sizes and age composition.

ДИНАМИКА ПОКАЗАТЕЛЕЙ СМЕРТНОСТИ НАСЕЛЕНИЯ ЦЕНТРАЛЬНОГО ФЕДЕРАЛЬНОГО ОКРУГА

Based on the data of the Federal State Statistics Service, the results of the analysis of mortality rates of the population of the Central Federal District for the period from 2016 to 2020 are presented. According to Rosstat, the number of deaths in Russia increased significantly in 2020. In January-December 2020, 2,124.5 thousand deaths were registered, which is 323.8 thousand people, or 18 % more than in January-December of the previous year. Of these, about half are those who died from COVID-19. The number of deaths from coronavirus during the pandemic exceeded 162 thousand people. The overall mortality rate increased to 14.5 % (deaths per 1,000 permanent population) against 12.3 % according to the 2019 data. The resumption of the trend of moderate growth in the number of deaths is quite expected, given the aging of the population and the wave-like deformations of the age structure of the Russian population. Now the age of 70 years and older is reached by numerous generations born in the 1950s, and the mortality rate already at the age of 60 years and older is an order of magnitude higher than in middle ages. In 2014-2019, age-related mortality rates decreased to one degree or another across all age groups, but at the same time the age composition of the population changed markedly. In 2019, the population in the age groups of 60 years and older was noticeably larger than in 2014. The only exception was a relatively small group of people 75-79 years old, born in 1940-1944. If in 2019 the age composition of the Russian population had been the same as in 2014, then with the age mortality rates of 2019, the total number of deaths would have been 6 % less than the actual one; or, in other words, the actual number of deaths turned out to be 6.4 % more due to changes in the age structure. However, the change in the age composition of the population can only partially explain an increased number of deaths in 2020. The increase turned out to be several times more than one would expect, and it mainly occurred at the end of the year.

Samarkand Region Population Age Composition and Increment of Labor Resources

Annotation: It is noted in the article that it is of great importance to research Samarkand Region population age composition and increment of labor resources. The direct impact of age composition to increment of labor resources is also studied in this article. Also, the issue of employment of the population is considered. Keywords: age composition, labor resources, population density, populated locality, city, village, children, adults, pensioners

The Different Effects of the Dynamic Population on Agricultural Productivity as a Comparison among Less and More Developed Countries

The objectives of this study are to identify and explain the different between population dynamic and agricultural productivity in LDC’s and MDC’s; as well as to investigate the relationships between population dynamic and agricultural productivity in LDC’s and MDC’s. The sample was involved 109 countries. According to the Human Development Report (2019), 58 of these countries are considering as LDC’s, while others 51 are considering as MDC’s. Means, standard deviation, T test, and Spearman correlation coefficients used as statistical techniques. Results of T test indicate a different statistically significant between LDC’s and MDC’s for the all dependent and independent variables, except the total population variable. The results of Spearman's correlation coefficients showed that the highest index of crop production is likely to occur among LDC’s that have a high population growth rate and more dependency ratio, while it occurs among MDC’s with the highest percentage of the population age composition (0-14). Furthermore, the results suggest that the highest food production index are more likely to occur among MDC’s that have the more growth rate of population, more growth rates of urban population, highest rate of net migration, lowest dependency ratio, highest percent of population age composition (0-14 and 15-64), and lowest percent of population age composition (65+), while it occurs among LDC’s with the high population growth rate. Moreover, the results suggest that the highest livestock production index are more likely to occur among MDC’s that have the highest growth rate of population, highest growth rate of urban population, highest rate of net migration, less dependency ratio, highest percent of population age composition (15-64), and lowest percent of population age composition (65+).