A RESOURCE-DEPENDENT COMPETITION MODEL:EFFECTS OF POPULATION PRESSURE AUGMENTED INDUSTRIALIZATION

In this paper,a nonlinear mathematical model is proposed and analyzed to study the effects of population pressure augmented industrialization on the survival of competing species dependent on resource.It is assumed that the growths of competing species are logistic and carrying capacities increase with increase in the density of resource biomass.Further,it is assumed that the resource biomass too is growing logistically in the envi-ronment and its carrying capacity decreases with the increase in densities of competing species and industrialization.The growth rate of population pressure is assumed to be proportional to the densities of competing species.Stabilities of all equilibria and con-ditions which influence the permanence of the system are carried out using theory of differential equations.Numerical simulations are performed to accomplish our analytical findings.It is shown that the equilibrium density of resource biomass decreases as(i)the growth rate coefficient of population pressure increases(ii)the growth rate coeffi-cient of industrialization due to population pressure increases and(iii)the growth rate coefficient of industrialization due to resource biomass increases.It is found that the competitive outcome alters with increase in the growth rate coefficient of population pressure.Decrease in the equilibrium densities of competing species is also noted with increase in the growth rate coefficient of industrialization due to resource biomass.

A MATHEMATICAL MODEL FOR THE DEPLETION OF FORESTRY RESOURCES DUE TO POPULATION AND POPULATION PRESSURE AUGMENTED INDUSTRIALIZATION

In this paper,a nonlinear mathematical model is proposed and analyzed to study the depletion of forestry resources caused simultaneously by population and population pressure augmented industrialization.The control of population pressure,using economic efforts is also considered in the modeling process.It is assumed that cumulative biomass density of forestry resources and the density of population follow logistic models.It is further assumed that the density of population and the level of industrialization increase as the cumulative biomass density of forestry resources increases.The cumulative density of economic efforts,which are applied to control the population pressure,is considered to be proportional to the population pressure.The model analysis shows that as the population pressure increases,the level of industrialization increases leading to decrease in the cumulative biomass density of forestry resources.It is found that if population pressure is controlled by using some economic efforts,the decrease in cumulative biomass density of forestry resources can be made much less than the case when no control is applied.It is also noted that if the population pressure augmented industrialization increases without control,the forestry resources may become extinct.

Relief Degree of Land Surface and Population Distribution of Mountainous Areas in China

Evaluation on the population pressure in the mountainous areas is a necessary condition for the protection and good governance. The evaluation depends on accurate population density assessment. Traditional methods used to calculate population density often adopt the administrative region as a scale for statistical analysis. These methods did not consider the effects of the relief degree of land surface(RDLS) on the population distribution. Therefore they cannot accurately reflect the degree of population aggregation, especially in mountainous areas. To explore this issue further, we took the mountainous areas of China as the research area. China has A total area of 666 km2 can be classified as mountainous area,accounting for 69.4% of the country's total landmass. The data used in this research included the digital elevation model(DEM) of China at a scale of 1:1,000,000, National population density raster data, the DEM and the national population density raster data. First, we determined the relief degree of land surface(RDLS). Next, we conducted a correlation analysis between the population distribution and the RDLS using the Statistical Package for Social Science(SPSS). Based on the correlation analysis results and population distribution, this new method was used to revise the provincial population density of themountainous areas. The revised results were used to determine the population pressure of different mountainous areas. Overall, the following results were obtained:(1) The RDLS was low in most mountainous areas(with a value between 0 and 3.5) and exhibited a spatial pattern that followed the physiognomy of China;(2) The relationship between the RDLS and population density were logarithmic, with an R2 value up to 0.798(p<0.05), and the correlation decreased from east to west;(3) The difference between the revised population density(RPD) and the traditional population density(PD) was larger in the southeastern region of China than in the northwestern region;(4) In addition, compared with traditional results, the revised result indicated that the population pressure was larger. Based on these results, the following conclusions were made:(1) the revised method for estimating population density that incorporates the RDLS is reasonable and practical,(2) the potential population pressure in the southeastern mountainous areas is substantial,(3) the characteristics of the terrain in the high mountainous areas are important for the scattered distribution of the population, and(4) the population distribution of mountainous areas in China should be guided by local conditions, such as social, economic, and topographic conditions.

Relationship between population competitive intensity and yield in maize cultivars

Competition is a common phenomenon in agriculture production.Research on the relationship between competitive ability and crop yield is extensive,but the results have been inconsistent.Few studies have focused on the relationship between population competitive intensity and yield of maize（Zea mays L.）cultivars.The main objective of this study was to determine if a consistent relationship exists between maize yield and competitive ability.A two-year field experiment was conducted,employing a de Wit replacement series design.When two maize cultivars were grown in a mixture,yield was reduced for the modern cultivar and increased for the older cultivar.In each replacement series,per plant level yield of each cultivar,and population level yield of the mixture,decreased with increasing proportion of the older cultivar.Competitive ratio（CR）reflected differences in competitive ability of the three maize cultivars.In each replacement series,population competition pressure（PCP）increased with increasing proportion of the older cultivar,indicating that the older cultivar was a strong competitor.Biomass yield,grain yield,harvest index,thousand-kernel weight,and kernel number per plant,were negatively correlated with PCP.Our results demonstrated that inter-cultivar competition affects maize productivity,and increasing PCP will decrease translocation of assimilates to grain and,ultimately,reduce yield.Therefore,there is a negative correlation between population competitive intensity and yield performance in maize,breeders should develop a communal ideotype that would not perform well in competition in future.

Nigerian Population Research on Environment,Gene and Health (NIPREGH)-objectives and protocol

Sub-Saharan Africa is currently undergoing an epidemiological transition from a disease burden largely attributable to communicable diseases to that resulting from a combination of both communicable and chronic non-communicable diseases.Data on chronic disease incidence,lifestyle,environmental and genetic risk factors are sparse in this region.This report aimed at providing relevant information in respect to risk factors that increase blood pressure and lead to development of intermediate cardiovascular phenotypes.We presented the rationale,objectives and key methodological features of the Nigerian Population Research on Environment,Gene and Health（NIPREGH） study.The challenges encountered in carrying out population study in this part of the world and the approaches at surmounting them were also presented.The preliminary data as at 20 November 2013 showed that out of the 205 individuals invited starting from early April 2013,160（72 women） consented and were enrolled;giving a response rate of 78%.Participants＇ age ranged from 18 to 80 years,with a mean（SD） of 39.8（12.4） years and they were of 34 different ethnic groups spread over 24 states out of the 36 states that constitute Nigeria.The mean（SD） of office and home blood pressures were 113.0（15.2） mm Hg systolic,73.5（12.5） mm Hg diastolic and 117.3（15.0） mm Hg systolic,and 76.0（9.6） mm Hg diastolic,respectively.Forty-three（26.8%） participants were hypertensive and 8（5.0%） were diabetic.In addition to having the unique potential of recruiting a cohort that is a true representative of the entire Nigerian population,NIPREGH is feasible and the objectives realisable.

Blood pressure differences in people with various individual characteristics in Guangdong Province

Objective To study the differences in blood pressure (BP) levels and the main factors raising BP among the population in Guangdong Province. Methods The data analyzed stem from the sampling survey of hypertension in Guangdong Province in 1991, covering 42, 894 subjects over 15 years old. Individual characteristics included age, sex, occupation, education, smoking, alcohol drinking and body mass index (BMI) . Results Systolic and diastolic BP increased with age. The hypertension prevalence rate in male is higher than in female. The age - adjusted prevalence rate in office personnel is the highest (12.9 % ) among all occupations. It was increased with education level and BMI (in people educated at university and over is 13. 1 % ), and higher in smokers and alcohol-drinkers than non-smokers and non -alcohol-drinkers. Conclusions Age, occupation, education, smoking, alcohol drinking and BMI all effect BP. These risk factors should be reduced in the Guangdong population.

Application of Remote Sensing and GIS Technology to the Study of Desertification of Arable Lands in North Shaanxi, China

The policy of the Chinese government concerning the horizontal expansion of the cultivated land through the reclamation of desert soils result in a total increase of 665.985 km 2 during the period 1987\|1999 in North Shaanxi. This increase is less than the loss in arable land by urbanization. The accelerated rate of change in agricultural areas calls for more rapid surveys of urbanization and loss of arable land. Remote sensing has a number of advantages over ground\|based methods for such surveys. The multi\|scale concept of remote sensing data help us study the problem in four towns. Several maps were produced to analyze the situation of urban coverage in different times. The evaluation of the status, rate and risk of urbanization are based on an accepted average of urban increase as 2% of population growth per year.

Tropical forest canopies and their relationships with climate and disturbance： results from a global dataset of consistent field-based measurements

Background： Canopy structure, defined by leaf area index （LAI）, fractional vegetation cover （FCover） and fraction of absorbed photosynthetically active radiation （fAPAR）, regulates a wide range of forest functions and ecosystem services. Spatially consistent field-measurements of canopy structure are however lacking, particularly for the tropics. Methods： Here, we introduce the Global LAI database： a global dataset of field-based canopy structure measurements spanning tropical forests in four continents （Africa, Asia, Australia and the Americas）. We use these measurements to test for climate dependencies within and across continents, and to test for the potential of anthropogenic disturbance and forest protection to modulate those dependences. Results： Using data collected from 887 tropical forest plots, we show that maximum water deficit, defined across the most arid months of the year, is an important predictor of canopy structure, with all three canopy attributes declining significantly with increasing water deficit. Canopy attributes also increase with minimum temperature, and with the protection of forests according to both active （within protected areas） and passive measures （through topography）. Once protection and continent effects are accounted for, other anthropogenic measures （e.g. human population） do not improve the model. Conclusions： We conclude that canopy structure in the tropics is primarily a consequence of forest adaptation to the maximum water deficits historically experienced within a given region. Climate change, and in particular changes in drought regimes may thus affect forest structure and function, but forest protection may offer some resilience against this effect.

Environmental Change in Agricultural Land in Southwest Cote d’Ivoire:Driving Forces and Impacts

Environmental conditions change in the Southwest of Cote d’Ivoire has been a major issue in development debates over the last decades. Using remote sensing based on land cover change analysis, climatic data, national statistical data, we analyzed the drivers of environmental change in Southwestern of Cote d’Ivoire. Being part of the perennial crops basin, Southwestern of Cote d’Ivoire has witnessed rapid degradation of environmental conditions caused by the conversion of forest areas to agricultural land during the last 20 - 30 years and by a combination of decline in precipitation, soil degradation, a diversity of policies with little concern for the environment and population pressure. We concluded that while climate variability has influenced environmental change in the area of Sassandra, various types of anthropogenic and State interventions in agriculture appear to have been the main underlying causes of environmental degradation.

Modeling the effects of environmental pollution intensified by urbanization on human population

A mathematical model is presented here to investigate the effects of environmental pollution,intensified by urbanization,on the density of human population.Here,urbanization is assumed to grow with constant rate and also,induced through growing population and the corresponding population pressure.The model analysis,qualitatively and numerically,show that though the growth of population or population pressure is responsible for the growing urbanization,but for very large increase of urbanization,the population may not survive in the long run due to environmental pollution driven by urbanization.

Social buffer or avoidance depends on the similarity of stress between queen ants

The association of unrelated ant queens(pleometrosis)is supposed to improve nest foundation and competitiveness under environmental stress,but its evolutionary maintenance is difficult to explain because only one of the queens survives after nest foundation.My aim was to test the potential effect of queen association as a social buffer,that is,as a mechanism reducing stress and improving fitness due to the benefits of social contact.I analyzed the survival,fecundity,and behavior of isolated and paired Lasius flavus queens exposed and not exposed to stressors(disturbing environmental conditions).I found no difference in survivorship between isolated and paired queens or between stressed and unstressed isolated queens.Groups in which 1 or 2 paired queens were stressed showed higher mortality.Unstressed queens died similarly to their stressed nestmates,suggesting stress transmission.A trend suggested that paired queens produced eggs more quickly,but eggs were produced similarly between isolated and paired queens.Social avoidance was observed in groups with 1 stressed and 1 unstressed queen.However,the groups with 2 stressed queens showed the expected behaviors according to social buffering:lower mobility and more interindividual inspection.My findings suggest the synergistic effect of pleometrosis and stress and the dependence of stress level similarity between nestmates on social buffering or rejection on ant queens.

Migration for survival under natural disasters:A reluctant and passive choice for agriculturalists in historical China

This study quantitatively investigates the long-term dynamics of the association between natural disasters and the migration of agriculturists in historical China. Population pressure is also studied because migration is a population density-dependent phenomenon. This study has adopted correlation analysis, multivariate linear/Poisson regression analyses, and Granger causality analysis to verify the linkages of natural disaster-migration and population-migration in historical China by collecting updated datasets. This study is the first attempt to reveal that the duration effects of natural disasters on the migration of agriculturalists are short-term and almost instantaneous. Although the agrarian society has a low buffering capacity, the effects of natural disasters within a short-term scale could be relieved to some extent. However, population pressure can push migration on a long-term scale despite its limited forcefulness.