Modeling Exponential Population Growth

Science.gov (United States)

McCormick, Bonnie

2009-01-01

The concept of population growth patterns is a key component of understanding evolution by natural selection and population dynamics in ecosystems. The National Science Education Standards (NSES) include standards related to population growth in sections on biological evolution, interdependence of organisms, and science in personal and social…

Population growth and consumption.

Science.gov (United States)

Chalkley, K

1997-04-01

The relationship between population growth, resource consumption, and environmental degradation is complex. The rise in "greenhouse gases" that will cause climatic change is clearly due to human activity, and pollutants are often concentrated in densely populated areas. However, even an area with a negative population growth, such as Russia, can experience severe environmental degradation due to poor management. Consumption patterns have the most effect on ozone depletion, while population growth threatens biodiversity of and within species through the destruction of ecosystems. Migration joins population growth and social factors, such as land inequality, as major causes of deforestation, and global demand for water is expected to increase faster than the rate of population growth. Coastal development and over-fishing threaten to deplete the oceans, while soil quality is threatened by inappropriate land use. Estimates of the earth's carrying capacity range from less than 3 billion to more than 44 billion people, indicating how difficult it is to assess this figure. Development efforts throughout the world may lead to human gains that will ultimately be negated by environmental losses. These factors have led to growing support for environmentally sustainable development.

Population growth to put pressure on some food supplies.

Science.gov (United States)

1997-01-01

Continued high population growth in developing countries is likely to lead to intense pressure to produce more rice, according to estimates from the Manila-based International Rice Research Institute (IRRI). Ms. Mercedita Sombilla, a research scientist with IRRI, said that the projected increase in Asia's population will be the major force in accelerating demand for rice. According to various issues of the ESCAP Population Data Sheet, the population of the region will have increased from 3.3 billion in 1995 to almost 4.6 billion in 2020. The greatest growth in demand is expected to come from the lower-income countries of Asia, such as Bangladesh, India, Myanmar, Philippines, and Viet Nam, she said. However, in terms of overall food supplies, the Organization for Economic Cooperation and Development (OECD) estimates that food supplies will be sufficient. "Expecting reasonably strong productivity growth to be sustainable, no global food crisis seems likely to occur" between now and 2020, the organization stated in its report entitled "The World in 2020: Towards a New Global Age". full text

Perspectives on population growth.

Science.gov (United States)

1996-09-01

Assume that everyone has the same information on population growth. There are many different opinions on what that information means and what should be done about it. Some people worry about current rates of growth, especially in the context of growing per capita consumption, and believe that all reasonable steps should be taken to reduce rates and stabilize population size. Others believe that growing populations can be accommodated by reducing consumption in rich countries, that technological progress will supply the new resources needed, that the development needed to support a larger population can be sustained, that large population size fosters prosperity, or that birth rates are falling and current growth is just temporary. These are all valid positions worthy of at least debate. Interest groups commonly acknowledgement population growth as a significant issue, but offer no response to it. Sometimes the issue goes unrecognized because it conflicts with a more highly valued personal agenda item. Finally, some responses come from confusion and anger rather than reasoning or self-interest. The proponents of these latter arguments bring nothing constructive to the debate.

TOPICAL PROBLEMS: The phenomenological theory of world population growth

Science.gov (United States)

Kapitza, Sergei P.

1996-01-01

Of all global problems world population growth is the most significant. Demographic data describe this process in a concise and quantitative way in its past and present. Analysing this development it is possible by applying the concepts of systems analysis and synergetics, to work out a mathematical model for a phenomenological description of the global demographic process and to project its trends into the future. Assuming self-similarity as the dynamic principle of development, growth can be described practically over the whole of human history, assuming the growth rate to be proportional to the square of the number of people. The large parameter of the theory and the effective size of a coherent population group is of the order of 105 and the microscopic parameter of the phenomenology is the human lifespan. The demographic transition — a transition to a stabilised world population of some 14 billion in a foreseeable future — is a systemic singularity and is determined by the inherent pattern of growth of an open system, rather than by the lack of resources. The development of a quantitative nonlinear theory of the world population is of interest for interdisciplinary research in anthropology and demography, history and sociology, for population genetics and epidemiology, for studies in evolution of humankind and the origin of man. The model also provides insight into the stability of growth and the present predicament of humankind, and provides a setting for discussing the main global problems.

Population growth, poverty and health.

Science.gov (United States)

Kibirige, J S

1997-07-01

One of the most popular explanations for the many problems that face Africa is population growth. Africa's population has doubled since 1960. Africa has the highest fertility rate in the world and the rate of population growth is higher than in any other region. At the same time, Africa faces a social and economic situation that is viewed by many as alarming. Among the problems that devastate Africa is that of persistent poor health. Africa has lower life expectancy, higher mortality rates and is affected by more disease and illness conditions than any other region. Focusing on sub-Saharan Africa, this paper examines the relationship between population growth, poverty and poor health. While most analyses have focused on population growth as an original cause of poverty and underdevelopment, this paper argues that while both population growth and poor health play a significant role in exacerbating the problem of poverty, they are themselves primary consequences of poverty rather than its cause.

Meeting the Sustainable Development Goals leads to lower world population growth.

Science.gov (United States)

Abel, Guy J; Barakat, Bilal; Kc, Samir; Lutz, Wolfgang

2016-12-13

Here we show the extent to which the expected world population growth could be lowered by successfully implementing the recently agreed-upon Sustainable Development Goals (SDGs). The SDGs include specific quantitative targets on mortality, reproductive health, and education for all girls by 2030, measures that will directly and indirectly affect future demographic trends. Based on a multidimensional model of population dynamics that stratifies national populations by age, sex, and level of education with educational fertility and mortality differentials, we translate these goals into SDG population scenarios, resulting in population sizes between 8.2 and 8.7 billion in 2100. Because these results lie outside the 95% prediction range given by the 2015 United Nations probabilistic population projections, we complement the study with sensitivity analyses of these projections that suggest that those prediction intervals are too narrow because of uncertainty in baseline data, conservative assumptions on correlations, and the possibility of new policies influencing these trends. Although the analysis presented here rests on several assumptions about the implementation of the SDGs and the persistence of educational, fertility, and mortality differentials, it quantitatively illustrates the view that demography is not destiny and that policies can make a decisive difference. In particular, advances in female education and reproductive health can contribute greatly to reducing world population growth.

On population growth near protected areas.

Directory of Open Access Journals (Sweden)

Lucas N Joppa

Full Text Available Protected areas are the first, and often only, line of defense in efforts to conserve biodiversity. They might be detrimental or beneficial to rural communities depending on how they alter economic opportunities and access to natural resources. As such, protected areas may attract or repel human settlement. Disproportionate increases in population growth near protected area boundaries may threaten their ability to conserve biodiversity.Using decadal population datasets, we analyze population growth across 45 countries and 304 protected areas. We find no evidence for population growth near protected areas to be greater than growth of rural areas in the same country. Furthermore, we argue that what growth does occur near protected areas likely results from a general expansion of nearby population centers.Our results contradict those from a recent study by Wittemyer et al., who claim overwhelming evidence for increased human population growth near protected areas. To understand the disagreement, we re-analyzed the protected areas in Wittemyer et al.'s paper. Their results are simply artifacts of mixing two incompatible datasets. Protected areas may experience unusual population pressures near their edges; indeed, individual case studies provide examples. There is no evidence, however, of a general pattern of disproportionate population growth near protected areas.

Exile and demographic population growth in Serbia

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Stevanović Radoslav

2005-01-01

Full Text Available The data of the 2002 population census on refugee population are analyzed in this paper with a basic aim to determine the significance (contribution of refugee corpus in demographic development of the Republic of Serbia. By analyzing the data, it has been determined that the refugee corpus does not significantly differ from the domicile population in the basic, above all demographic and other qualitative characteristics. The differences which can be noticed with certain (primarily socio-economic characteristics, due to the proportionally small participation of refugee persons in relation to the total (domicile population, could not significantly influence the total demographic, socio-economic and other characteristics of the population of central Serbia and Vojvodina. The most significant contribution of refugee (classifying the refugee corpus in the country's total population is reflected in the mitigation of the depopulation trend, namely population growth, not only both micro-entities, but also lower administrative-territorial entities (districts depending on the enumerated refugee population in them. However, population projections indicate that by the middle of this century (2050 the positive effects of the basically larger number of inhabitants will be lost caused by the inflow of refugee population.

Incorporating regional growth into forecasts of greenhouse gas emissions from project-level residential and commercial development

International Nuclear Information System (INIS)

Rowangould, Dana; Eldridge, Melody; Niemeier, Deb

2013-01-01

To better understand the greenhouse gas (GHG) implications of land use planning decisions, regional planning organizations have developed tools to forecast the emissions from project-level residential and commercial development. This paper reviews the state of GHG emissions forecasting methods for project-level development. We argue that when forecasting changes in regional emissions it is important to make explicit what is assumed about a project′s effect on the population of residents and businesses in the region. We present five regional growth assumptions capturing the range of ways that project-level development might influence (i) construction and occupancy of similar developments elsewhere in a region and (ii) relocation of the initial activities that occur on-site before the project is built. We show that current forecasting tools inconsistently address the latter when they are interpreted as forecasted changes in regional emissions. Using a case study in Yolo County, California we demonstrate that forecasted changes in regional emissions are greatly affected by the regional growth assumption. In the absence of information about which regional growth assumption is accurate, we provide guidelines for selection of a conservative regional growth assumption. - Highlights: • Current tools inconsistently forecast GHG emissions from project-level development. • We outline five assumptions about how projects may affect regional growth. • Our assumptions capture a range of economic and population effects of projects. • Our case study shows that growth assumptions greatly affect regional GHG estimates. • We provide guidelines for selecting a conservative regional growth assumption

bayesPop: Probabilistic Population Projections

Directory of Open Access Journals (Sweden)

Hana Ševčíková

2016-12-01

Full Text Available We describe bayesPop, an R package for producing probabilistic population projections for all countries. This uses probabilistic projections of total fertility and life expectancy generated by Bayesian hierarchical models. It produces a sample from the joint posterior predictive distribution of future age- and sex-specific population counts, fertility rates and mortality rates, as well as future numbers of births and deaths. It provides graphical ways of summarizing this information, including trajectory plots and various kinds of probabilistic population pyramids. An expression language is introduced which allows the user to produce the predictive distribution of a wide variety of derived population quantities, such as the median age or the old age dependency ratio. The package produces aggregated projections for sets of countries, such as UN regions or trading blocs. The methodology has been used by the United Nations to produce their most recent official population projections for all countries, published in the World Population Prospects.

bayesPop: Probabilistic Population Projections

Science.gov (United States)

Ševčíková, Hana; Raftery, Adrian E.

2016-01-01

We describe bayesPop, an R package for producing probabilistic population projections for all countries. This uses probabilistic projections of total fertility and life expectancy generated by Bayesian hierarchical models. It produces a sample from the joint posterior predictive distribution of future age- and sex-specific population counts, fertility rates and mortality rates, as well as future numbers of births and deaths. It provides graphical ways of summarizing this information, including trajectory plots and various kinds of probabilistic population pyramids. An expression language is introduced which allows the user to produce the predictive distribution of a wide variety of derived population quantities, such as the median age or the old age dependency ratio. The package produces aggregated projections for sets of countries, such as UN regions or trading blocs. The methodology has been used by the United Nations to produce their most recent official population projections for all countries, published in the World Population Prospects. PMID:28077933

Modeling effects of cadmium on population growth of Palaemonetes pugio: Results of a full life cycle exposure

International Nuclear Information System (INIS)

Manyin, Teresa; Rowe, Christopher L.

2008-01-01

In an 8-month laboratory experiment, Palaemonetes pugio (grass shrimp) were exposed to aqueous cadmium (free cadmium ion concentrations of 1.51 or 2.51 μg Cd 2+ /L) for an entire life cycle, from larva to reproductive adult and through to production of second-generation larva. Individual-level effects on survival, life stage duration, and reproduction were measured, and population growth was projected using two models: a stage-based matrix model and a z-transformed life cycle graph analysis. Adult survival was significantly reduced at 2.51 μg Cd 2+ /L, but cadmium exposure had no effects on survival or stage duration of embryos, larvae, or juveniles. Survival of second-generation larvae was unaffected by maternal exposure. Brood size was reduced by 27% at 1.51 μg Cd 2+ /L and by 36% at 2.51 μg Cd 2+ /L. The percent of females in the population that was gravid was approximately 50% lower at 2.51 μg Cd 2+ /L, compared to controls. Both population models projected a dose-dependent decrease in population growth rate (λ), up to a 12% reduction at 2.51 μg Cd 2+ /L, which can be attributed mainly to contributions from reproductive effects. Elasticity analysis revealed that population growth rate was most sensitive to changes in survival of juveniles and adults. However, lethal effects of cadmium made only a small contribution to the effect on population growth rate. Even though both models project positive growth (λ > 1) of grass shrimp populations exposed to low concentrations of cadmium, the ability of populations to withstand predation pressure would be compromised

Modeling effects of cadmium on population growth of Palaemonetes pugio: Results of a full life cycle exposure

Energy Technology Data Exchange (ETDEWEB)

Manyin, Teresa [University of Maryland Center for Environmental Science, Chesapeake Biological Laboratory, PO Box 38, 1 Williams Street, Solomons, MD 20688 (United States)], E-mail: manyin@cbl.umces.edu; Rowe, Christopher L. [University of Maryland Center for Environmental Science, Chesapeake Biological Laboratory, PO Box 38, 1 Williams Street, Solomons, MD 20688 (United States)

2008-06-23

In an 8-month laboratory experiment, Palaemonetes pugio (grass shrimp) were exposed to aqueous cadmium (free cadmium ion concentrations of 1.51 or 2.51 {mu}g Cd{sup 2+}/L) for an entire life cycle, from larva to reproductive adult and through to production of second-generation larva. Individual-level effects on survival, life stage duration, and reproduction were measured, and population growth was projected using two models: a stage-based matrix model and a z-transformed life cycle graph analysis. Adult survival was significantly reduced at 2.51 {mu}g Cd{sup 2+}/L, but cadmium exposure had no effects on survival or stage duration of embryos, larvae, or juveniles. Survival of second-generation larvae was unaffected by maternal exposure. Brood size was reduced by 27% at 1.51 {mu}g Cd{sup 2+}/L and by 36% at 2.51 {mu}g Cd{sup 2+}/L. The percent of females in the population that was gravid was approximately 50% lower at 2.51 {mu}g Cd{sup 2+}/L, compared to controls. Both population models projected a dose-dependent decrease in population growth rate ({lambda}), up to a 12% reduction at 2.51 {mu}g Cd{sup 2+}/L, which can be attributed mainly to contributions from reproductive effects. Elasticity analysis revealed that population growth rate was most sensitive to changes in survival of juveniles and adults. However, lethal effects of cadmium made only a small contribution to the effect on population growth rate. Even though both models project positive growth ({lambda} > 1) of grass shrimp populations exposed to low concentrations of cadmium, the ability of populations to withstand predation pressure would be compromised.

Projecting county-level populations under three future scenarios: a technical document supporting the Forest Service 2010 RPA Assessment

Science.gov (United States)

Stanley J. Zarnoch; H. Ken Cordell; Carter J. Betz

2010-01-01

County-level population projections from 2010 to 2060 are developed under three national population growth scenarios for reporting in the 2010 Renewable Resources Planning Act (RPA) Assessment. These population growth scenarios are tied to global futures scenarios defined by the Intergovernmental Panel on Climate Change (IPCC), a program within the United Nations...

Population Growth Types in India, 1961-71

Science.gov (United States)

Chakravarti, A. K.

1976-01-01

An effective means of cartographic representation of India's population growth and its spatial characteristics is the focus of this paper. A population growth index and population growth types are discussed. (Author/ND)

National Health Expenditure Projections, 2017-26: Despite Uncertainty, Fundamentals Primarily Drive Spending Growth.

Science.gov (United States)

Cuckler, Gigi A; Sisko, Andrea M; Poisal, John A; Keehan, Sean P; Smith, Sheila D; Madison, Andrew J; Wolfe, Christian J; Hardesty, James C

2018-03-01

Under current law, national health spending is projected to grow 5.5 percent annually on average in 2017-26 and to represent 19.7 percent of the economy in 2026. Projected national health spending and enrollment growth over the next decade is largely driven by fundamental economic and demographic factors: changes in projected income growth, increases in prices for medical goods and services, and enrollment shifts from private health insurance to Medicare that are related to the aging of the population. The recent enactment of tax legislation that eliminated the individual mandate is expected to result in only a small reduction to insurance coverage trends.

Population growth and infant mortality

OpenAIRE

Fabella, Christina

2008-01-01

The relationship between population growth and economic outcomes is an issue of great policy significance. In the era of the Millennium Development Goals, poverty and its correlates have become the compelling issues. Economic growth may not automatically translate into reductions in poverty and its correlates (may not trickle down) if income distribution is at the same time worsening. We therefore investigate the direct effect of population growth on infant mortality for various income catego...

Approach to assessing local socio-cultural impacts using projections of population growth and composition

Energy Technology Data Exchange (ETDEWEB)

Baldwin, T. E.; Poetsch, R.

1977-08-01

All assessment of future domestic development projects assumes that the problems to be examined have been properly identified and defined before the application of a projection technique. An attempt is made to codify socio-cultural problems mentioned in literature and clarify how existing demographic projection techniques can be applied to assessing the problems. The relationship between changes in local population size and composition induced by in-migration and the potential for socio-cultural incompatibilities is described heuristically. For simplification, the problems expected to emerge from differences in demographic composition are classified into three categories: (1) service needs, such as those for housing, recreation, and education; (2) types of social organizations related to capacities for, or constraints on, reaping the benefits of rapid economic development and social changes (e.g., employment and income); and (3) attitudes, values, and cultural perspectives. These areas of concern are very broad, and quantitative projections of population size and composition are more easily related to the first than to the third. Although demographic projection provides a valuable tool for estimating future social change, the knowledge about cause and effect is not sufficient to support the quantification of socio-cultural impact. Therefore, the projections are used only as relative indicators and the assessments of socio-cultural impact based on them are qualitative only. Therefore, identification and assessment of socio-cultural impacts are a means of developing plans to overcome the expected problems.

Population growth changes targets for immunization.

Science.gov (United States)

Tuljapurkar, S; John, A M

1995-01-01

The faster the rate of population growth in developing countries, the less likely it is that current protocols for immunization against measles, rubella, and mumps will eradicate these childhood diseases. Standard protocols (timing, percentage of children to be immunized) do not take into account the rapid rates of population growth in developing countries (3.0% per year on average in sub-Saharan Africa and 2.0% in the rest of Africa, in Latin America, and in Asia, excluding China). Most public health planning models in this area were created based on static infant populations. The World Health Organization advises vaccinating at least 85% of children aged 6 to 9 months, a 3-month immunization window during which maternal antibodies are low (so the vaccination takes) and herd immunity is high (the probability that a child will encounter the disease is low because most children have been immunized). In practice, the immunization window in developing countries is 1 year or more. More susceptible children are present than assumed by the models. A larger number of susceptible babies are added each year during rapid population growth. As the age range for immunization widens, a higher percentage of children must be vaccinated to eradicate disease (chart). The proportion of each birth cohort that must be immunized rises as the population growth rate increases. At zero population growth, 94% must be vaccinated; at population growth rates greater than 3%, 98% must be vaccinated.

Kinetic Model of Growth of Arthropoda Populations

Science.gov (United States)

Ershov, Yu. A.; Kuznetsov, M. A.

2018-05-01

Kinetic equations were derived for calculating the growth of crustacean populations ( Crustacea) based on the biological growth model suggested earlier using shrimp ( Caridea) populations as an example. The development cycle of successive stages for populations can be represented in the form of quasi-chemical equations. The kinetic equations that describe the development cycle of crustaceans allow quantitative prediction of the development of populations depending on conditions. In contrast to extrapolation-simulation models, in the developed kinetic model of biological growth the kinetic parameters are the experimental characteristics of population growth. Verification and parametric identification of the developed model on the basis of the experimental data showed agreement with experiment within the error of the measurement technique.

Construction and analysis of a giant gartersnake (Thamnophis gigas) population projection model

Science.gov (United States)

Rose, Jonathan P.; Ersan, Julia S. M.; Wylie, Glenn D.; Casazza, Michael L.; Halstead, Brian J.

2018-03-19

The giant gartersnake (Thamnophis gigas) is a state and federally threatened species precinctive to California. The range of the giant gartersnake has contracted in the last century because its wetland habitat has been drained for agriculture and development. As a result of this habitat alteration, giant gartersnakes now largely persist in and near rice agriculture in the Sacramento Valley, because the system of canals that conveys water for rice growing approximates historical wetland habitat. Many aspects of the demography of giant gartersnakes are unknown, including how individuals grow throughout their life, how size influences reproduction, and how survival varies over time and among populations. We studied giant gartersnakes throughout the Sacramento Valley of California from 1995 to 2016 using capture-mark-recapture to study the growth, reproduction, and survival of this threatened species. We then use these data to construct an Integral Projection Model, and analyze this demographic model to understand which vital rates contribute most to the growth rate of giant gartersnake populations. We find that giant gartersnakes exhibit indeterminate growth; growth slows as individuals’ age. Fecundity, probability of reproduction, and survival all increase with size, although survival may decline for the largest female giant gartersnakes. The population growth rate of giant gartersnakes is most influenced by the survival and growth of large adult females, and the size at which 1 year old recruits enter the population. Our results indicate that management actions benefitting these influential demographic parameters will have the greatest positive effect on giant gartersnake population growth rates, and therefore population persistence. This study informs the conservation and management of giant gartersnakes and their habitat, and illustrates the effectiveness of hierarchical Bayesian models for the study of rare and elusive species.

Africa region population projections - 1988-89

OpenAIRE

Vu, My T.; Bos, Eduard; Bulatao, Rodolfo A.

1988-01-01

The report which is part of a series, presents population projection tables for each country in the Africa region. The report provides an explanation on projection results as well as a description of the projection methodology, summarizing the main results. The projections in the report cover the period 1985 - 2150. This time period allows countries to approach stability. The key elements in these projections are the base year (mid 1985). Total population estimates and age - sex structures ar...

On reducibility and ergodicity of population projection matrix models

DEFF Research Database (Denmark)

Stott, Iain; Townley, Stuart; Carslake, David

2010-01-01

from all stages to all other stages) and therefore ergodic (whatever initial stage structure is used in the population projection, it will always exhibit the same stable asymptotic growth rate). 2. Evaluation of 652 PPM models for 171 species from the literature suggests that 24·7% of PPM models...... structure used in the population projection). In our sample of published PPMs, 15·6% are non-ergodic. 3. This presents a problem: reducible–ergodic models often defy biological rationale in their description of the life cycle but may or may not prove problematic for analysis as they often behave similarly...... of reducibility in published PPMs, with significant implications for the predictive power of such models in many cases. We suggest that as a general rule, reducibility of PPM models should be avoided. However, we provide a guide to the pertinent analysis of reducible matrix models, largely based upon whether...

Does pollen limitation affect population growth of the endangered Dracocephalum austriacum L.?

Czech Academy of Sciences Publication Activity Database

Castro, Sílvia; Dostálek, Tomáš; van der Meer, S.; Oostermeijer, G.; Münzbergová, Zuzana

2015-01-01

Roč. 57, č. 1 (2015), s. 105-116 ISSN 1438-3896 R&D Projects: GA ČR GP13-10850P; GA ČR GAP505/10/0593 Institutional support: RVO:67985939 Keywords : Dracocephalum austriacum * pollination ecology * population growth rate Subject RIV: EF - Botanics Impact factor: 1.698, year: 2015

"India Population Projects" in Karnataka.

Science.gov (United States)

Reddy, P H; Badari, V S

1991-12-01

An overview, objectives, implementation, and research and evaluation studies of 2 India Population Projects in Karnataka are presented. The India Population Project I (IPP-I) was conducted in Karnataka and Uttar Pradesh. India Population Project III (IPP-III) took place between 1984-92 in 6 districts of Karnataka: Belgaum, Bijapur, Dharwad, Bidar, Gulbarga, and Raichur, and 4 districts in Kerala. The 6 districts in Karnataka accounted for 36% (13.2 million) of the total national population. The project cost was Rs. 713.1 million which was shared by the World Bank, and the Indian national and regional government. Due to poor past performance, these projects were undertaken to improve health and family welfare status. Specific project objectives are outlined. IPP-I included an urban component, and optimal Government of India program, and an intensive rural initiative. The urban program aimed to improved pre- and postnatal services and facilities, and the family planning (FP) in Bangalore city. The rural program was primarily to provide auxiliary nurse-midwives and hospitals and clinics, and also supplemental feeding program for pregnant and nursing mothers and children up to 2 years. The government program provided FP staff and facilities. IPP-I had 3 units to oversee building construction, to recruit staff and provide supplies and equipment, and to establish a Population Center. IPP-III was concerned with service delivery; information, education, and communication efforts (IEC) and population education; research and evaluation; and project management. Both projects contributed significantly to improving the infrastructure. A brief account of the types and kinds of studies undertaken is given. Studies were grouped into longitudinal studies of fertility, mortality, and FP; management information and evaluation systems for health and family welfare programs; experimental strategies; and other studies. Research and evaluation studies in IPP-III encompassed studies in

The finite state projection approach to analyze dynamics of heterogeneous populations

Science.gov (United States)

Johnson, Rob; Munsky, Brian

2017-06-01

Population modeling aims to capture and predict the dynamics of cell populations in constant or fluctuating environments. At the elementary level, population growth proceeds through sequential divisions of individual cells. Due to stochastic effects, populations of cells are inherently heterogeneous in phenotype, and some phenotypic variables have an effect on division or survival rates, as can be seen in partial drug resistance. Therefore, when modeling population dynamics where the control of growth and division is phenotype dependent, the corresponding model must take account of the underlying cellular heterogeneity. The finite state projection (FSP) approach has often been used to analyze the statistics of independent cells. Here, we extend the FSP analysis to explore the coupling of cell dynamics and biomolecule dynamics within a population. This extension allows a general framework with which to model the state occupations of a heterogeneous, isogenic population of dividing and expiring cells. The method is demonstrated with a simple model of cell-cycle progression, which we use to explore possible dynamics of drug resistance phenotypes in dividing cells. We use this method to show how stochastic single-cell behaviors affect population level efficacy of drug treatments, and we illustrate how slight modifications to treatment regimens may have dramatic effects on drug efficacy.

A phenomenological theory of world population growth and global problems

CERN Document Server

Kapitza, Sergei P

1996-01-01

Of all global problems world population growth is the most significant one. To describe this process in its past and project it into the future a mathematical model is worked out. It treats the world population as an entity, seen as an open and evolv The approach is phenomenological and growth over very many generations is assumed to be selfsimilar and described by scaling. In terms of kinetics, the growth rate is proportional to the square of the total number of people and the nonlinear hyperbol of all mechanisms that contribute to our development in a collective interactive process. The model gives an estimate of the beginning of human evolution c.a. 4.4 million years ago and of the total number of people who ever lived c.a. 100 billion. In the scope of the model large scale cycles defined by history and anthropology are shown to be uniformly spaced in time on a logarithmic scale, expressing and inherent periodicity. As we approach the present, this progression of cycles is now termo transition. This is a s...

National health expenditure projections, 2013-23: faster growth expected with expanded coverage and improving economy.

Science.gov (United States)

Sisko, Andrea M; Keehan, Sean P; Cuckler, Gigi A; Madison, Andrew J; Smith, Sheila D; Wolfe, Christian J; Stone, Devin A; Lizonitz, Joseph M; Poisal, John A

2014-10-01

In 2013 health spending growth is expected to have remained slow, at 3.6 percent, as a result of the sluggish economic recovery, the effects of sequestration, and continued increases in private health insurance cost-sharing requirements. The combined effects of the Affordable Care Act's coverage expansions, faster economic growth, and population aging are expected to fuel health spending growth this year and thereafter (5.6 percent in 2014 and 6.0 percent per year for 2015-23). However, the average rate of increase through 2023 is projected to be slower than the 7.2 percent average growth experienced during 1990-2008. Because health spending is projected to grow 1.1 percentage points faster than the average economic growth during 2013-23, the health share of the gross domestic product is expected to rise from 17.2 percent in 2012 to 19.3 percent in 2023. Project HOPE—The People-to-People Health Foundation, Inc.

Population and prehistory I: Food-dependent population growth in constant environments.

Science.gov (United States)

Lee, Charlotte T; Tuljapurkar, Shripad

2008-06-01

We present a demographic model that describes the feedbacks between food supply, human mortality and fertility rates, and labor availability in expanding populations, where arable land area is not limiting. This model provides a quantitative framework to describe how environment, technology, and culture interact to influence the fates of preindustrial agricultural populations. We present equilibrium conditions and derive approximations for the equilibrium population growth rate, food availability, and other food-dependent measures of population well-being. We examine how the approximations respond to environmental changes and to human choices, and find that the impact of environmental quality depends upon whether it manifests through agricultural yield or maximum (food-independent) survival rates. Human choices can complement or offset environmental effects: greater labor investments increase both population growth and well-being, and therefore can counteract lower agricultural yield, while fertility control decreases the growth rate but can increase or decrease well-being. Finally we establish equilibrium stability criteria, and argue that the potential for loss of local stability at low population growth rates could have important consequences for populations that suffer significant environmental or demographic shocks.

Population ageing alongside health care spending growth

Directory of Open Access Journals (Sweden)

Jakovljević Mihajlo

2017-01-01

Full Text Available The Silver Tsunami or population ageing has become a globally widespread phenomenon. The purpose of this review is to observe its dynamics and consequences from a local Balkan perspective. The main drivers of this unique demographic evolution are extended longevity, improved early childhood survival, absorption of women into the labor markets, and consequences of sexual revolution leading to falling female fertility. This process lasting well over a century is taking its toll on contemporary societies. Major side effects are shrinking young labor force and growing pool of elderly and retired citizens in many countries. This equation tends to worsen further in the future threatening long-term financial sustainability of public social and health insurance funds. Notable health expenditure growth, accelerating worldwide since the 1960s, is to a large degree attributable to ageing itself. Growing share of senior citizens increases demand for medical services and costs of health care provision. Home-based care provided by the family caregivers presents another important reality putting a huge burden on modern communities. Serbs are no exception in this landscape. Historical demographic evolution of this nation gives a clear evidence of advanced and accelerated ageing, which is well documented in post-World War II era. This synthesis of rich published evidence shows clear upward parallel trend between the pace of population aging and the growth of health expenditure. National authorities shall be forced to consider reform of the current health care financing pattern inherited from the demographic growth era. This might be the only way to smooth out the impact of population ageing on the financial sustainability of the health system and long-term medical care in Serbia. [Project of the Serbian Ministry of Education, Science and Technological Development, Grant no. OI 175014

Projected demographic composition of the United States population of people living with diagnosed HIV.

Science.gov (United States)

Hood, Julia E; Golden, Matthew R; Hughes, James P; Goodreau, Steven M; Siddiqi, Azfar-E-Alam; Buskin, Susan E; Hawes, Stephen E

2017-12-01

The transformation of HIV from a fatal disease to lifelong disease has resulted in an HIV-infected population that is growing and aging, placing new and increasing demands on public programs and health services. We used National HIV Surveillance System and US census data to project the demographic composition of the population of people living with diagnosed HIV (PLWDH) in the United States through 2045. The input parameters for the projections include: (1) census projections, (2) number of people with an existing HIV diagnosis in 2013, (3) number of new HIV diagnoses in 2013, and (4) death rate within the PLWDH population in 2013. Sex-, risk group-, and race-specific projections were estimated through an adapted Leslie Matrix Model for age-structured populations. Projections for 2013-2045 suggest that the number of PLWDH in the U.S. will consistently grow, from 917,294 to 1,232,054, though the annual growth rate will slow from 1.8% to 0.8%. The number of PLWDH aged 55 years and older will increase from 232,113 to 470,221. The number of non-Hispanic (NH) African Americans/Blacks and Hispanics is projected to consistently grow, shifting the racial/ethnic composition of the US PLWDH population from 32 to 23% NH-White, 42 to 38% NH-Black, and 20-32% Hispanic between 2013 and 2045. Given current trends, the composition of the PLWDH population is projected to change considerably. Public health practitioners should anticipate large shifts in the age and racial/ethnic structure of the PLWDH population in the United States.

The demographic consequences of mutualism: ants increase host-plant fruit production but not population growth.

Science.gov (United States)

Ford, Kevin R; Ness, Joshua H; Bronstein, Judith L; Morris, William F

2015-10-01

The impact of mutualists on a partner's demography depends on how they affect the partner's multiple vital rates and how those vital rates, in turn, affect population growth. However, mutualism studies rarely measure effects on multiple vital rates or integrate them to assess the ultimate impact on population growth. We used vital rate data, population models and simulations of long-term population dynamics to quantify the demographic impact of a guild of ant species on the plant Ferocactus wislizeni. The ants feed at the plant's extrafloral nectaries and attack herbivores attempting to consume reproductive organs. Ant-guarded plants produced significantly more fruit, but ants had no significant effect on individual growth or survival. After integrating ant effects across these vital rates, we found that projected population growth was not significantly different between unguarded and ant-guarded plants because population growth was only weakly influenced by differences in fruit production (though strongly influenced by differences in individual growth and survival). However, simulations showed that ants could positively affect long-term plant population dynamics through services provided during rare but important events (herbivore outbreaks that reduce survival or years of high seedling recruitment associated with abundant precipitation). Thus, in this seemingly clear example of mutualism, the interaction may actually yield no clear benefit to plant population growth, or if it does, may only do so through the actions of the ants during rare events. These insights demonstrate the value of taking a demographic approach to studying the consequences of mutualism.

Population Estimates and Projections: Projections of the Population of the United States, 1975 to 2050. Current Population Reports, Series P-25, No. 601.

Science.gov (United States)

Gibson, Campbell; Wetrogan, Signe

This report presents population projections of the United States by age, sex, and the components of population changes, births, deaths, and net immigration. These projections are shown annually by race--white and black--from 1975 to 2000 and in less detail for the total population from 2000 to 2050. In 1974, the population of the United States,…

The sensitivity analysis of population projections

NARCIS (Netherlands)

Caswell, H.; Sánchez Gassen, N.

2015-01-01

Background Population projections using the cohort component method can be written as time-varying matrix population models. The matrices are parameterized by schedules of mortality, fertility, immigration, and emigration over the duration of the projection. A variety of dependent variables are

Population Growth and Sprawl on the Pine Ridge Indian Reservation, South Dakota

Science.gov (United States)

Campbell, R. L.

2006-05-01

The most important impact on global land cover is human use and development. With the recent population growth occurring on the reservations in South Dakota, especially Pine Ridge Indian Reservation, the towns and agricultural areas of the reservation are undergoing a change. Although urban sprawl certainly is not a consideration on the reservations, the population explosion currently underway has seen a subsequent increase in rural sprawl. In this case, rural sprawl is defined as exponential population growth and geographic expansion of remote reservation communities. Using satellite imagery and software to render these images is a cost effective way to investigate this growth. Also, using remotely sensed data and a GIS (geographic information system) package can address different issues that concern people and communities in and around the Pine Ridge area. The objective of my project is to observe land use change on the Pine Ridge Indian reservation using Geographic Information Systems such as; ARCGis 9, ENVI, and Multispec, along with Landsat 4, 5, and 7 imagery over the past 20 years.

Projection of Chinese motor vehicle growth, oil demand, and CO2 emissions through 2050

Science.gov (United States)

2007-01-01

During this study a methodology was developed to project growth trends of the motor vehicle population and associated oil demand and carbon dioxide (CO2) emissions in China through 2050. In particular, the numbers of highway vehicles, motorcycles, an...

Uncertainty in population growth rates: determining confidence intervals from point estimates of parameters.

Directory of Open Access Journals (Sweden)

Eleanor S Devenish Nelson

Full Text Available BACKGROUND: Demographic models are widely used in conservation and management, and their parameterisation often relies on data collected for other purposes. When underlying data lack clear indications of associated uncertainty, modellers often fail to account for that uncertainty in model outputs, such as estimates of population growth. METHODOLOGY/PRINCIPAL FINDINGS: We applied a likelihood approach to infer uncertainty retrospectively from point estimates of vital rates. Combining this with resampling techniques and projection modelling, we show that confidence intervals for population growth estimates are easy to derive. We used similar techniques to examine the effects of sample size on uncertainty. Our approach is illustrated using data on the red fox, Vulpes vulpes, a predator of ecological and cultural importance, and the most widespread extant terrestrial mammal. We show that uncertainty surrounding estimated population growth rates can be high, even for relatively well-studied populations. Halving that uncertainty typically requires a quadrupling of sampling effort. CONCLUSIONS/SIGNIFICANCE: Our results compel caution when comparing demographic trends between populations without accounting for uncertainty. Our methods will be widely applicable to demographic studies of many species.

Population growth and development: the Kenyan experience.

Science.gov (United States)

Nyamwange, M

1995-01-01

Rapid population growth in Kenya and high fertility impacts negatively on economic development. The growth and high fertility results in declines in gross national product, per capita food consumption, and land quality; a high dependency ratio; urban crowding; and inadequate health systems. East Africa has the highest crude birth rates in Africa, and Kenya has the highest birth rate of 54/1000 population in East Africa. The African crude death rate is 50% higher than the world average, but Kenya's death rate is the lowest in East Africa and comparable to North American and European death rates. Kenya has the highest rate of natural increase of about 4%. Population growth rates rose over the decades. Kenya's average population density is well above the sub-Saharan African average and much lower than very high density countries. Population is unequally distributed. Regional densities are widely divergent, and the highest densities in Western province are well above densities in Rwanda and Burundi. Urban growth has increased, as has migration to urban areas. Nairobi has 57% of urban population. Improved health and nutrition have contributed to increased life expectancy. The desired family size is large. The impact of demographic factors on economic conditions is evident in the decline in gross national product per capita growth to under 1% during 1972-88. A slight upswing occurred during 1988-93, but other crises are emerging. Food production has not kept pace with population growth. Production has been low due to serious land degradation, short fallow periods, and traditional farming practices. Population pressure has forced families to shift agriculture onto marginal lands, and desertification has increased. A growing proportion of the population is unemployed or underemployed. Population programs should address the underlying conditions for fertility decline.

Political economy of population growth.

Science.gov (United States)

Mehta, S; Mehta, H S

1987-01-01

Tracing the origin of political economy as a class-science, this paper focuses on the political economy of population growth. Exposing the limitations of Malthusian ideas and their invalidity even for the capitalist economies, it discusses the subsequent revival of the Malthusian model during the period of de-colonization and the misinterpretation of the relationship between population growth and development in the developing and developed countries. Taking India, China, and Japan as some case studies, the paper examines the relationship between birth rate levels and some correlates. It elaborates on the Indian experience, emphasizing the association of population growth with poverty and unemployment and lays bare some of the hidden causes of these phenomena. The authors examine some interstate variations in India and identify constraints and prospects of the existing population policy. The paper proposes outlines of a democratic population policy as an integral part of India's development strategy which should recognize human beings not simply as consumers but also as producers of material values. It pleads for 1) restructuring of property relations; 2) bringing down the mortality rates and raising of the literacy levels, especially among females; and 3) improving nutritional levels, as prerequisites for bringing down birth rates.

[African population growth: status and prospects].

Science.gov (United States)

Tabutin, D

1991-01-01

Despite great improvements over the past several years, the quality of demographic data in Africa is still a problem, and Africa remains the least well known continent. Population growth is extremely rapid, with all countries growing at annual rates of over 3%. The natural increase rate even shows some signs of increasing slightly in the next decade or so. Africa's population was estimated at 220 million in 1950, 650 million at present, and is projected at 1.5 billion by 2025. Africans represented 9% of the world population in 1960, but will increase to 19% around 2025. The rapid population growth is the result of declining mortality since the 1950s unmatched by changes in fertility. There are significant socioeconomic and rural-urban mortality differentials in Africa, but as yet only highly educated urbanites have measurably reduced their family size. 2 consequences of this rapid growth are the youth of the population, with almost 50% under 20 years, and its high density in some areas. By 2025, 18 countries will have densities of over 100 persons per sq km. Almost everywhere in Africa, family sizes are at least 6 children/woman. 3 factors explaining this high level of fertility are the earliness and universality of marriage, rates of contraceptive usage of only 4-10% in most countries, and declining durations of breast feeding and sexual abstinence, which traditionally served as brakes on fertility. As a rule, women marry young and remain married until the end of their reproductive years. Divorce and widowhood are common, but remarriage is usually rapid if the woman is still of reproductive age. Life expectancy at birth in sub-Saharan Africa has increased from some 36 years around 1950 to 50 years at present. Progress in control of mortality, and especially infant mortality, has been slower than expected, and Africa still has by far the lowest life expectancy of any major region. Regional, rural-urban, and socioeconomic mortality differentials are considerable and

Population growth and its implications

Directory of Open Access Journals (Sweden)

Badii, M. H.

2005-01-01

Full Text Available Human populations have grown at an unprecedented rate over the past three centuries. By 2001, the world population stood at 6.2 billion people. If the current trend of 1.4 % per year persists, the population will double in 51years. Most of that growth will occur in the less developed countries of Asia, Africa, and Latin America. There is a serious concern that the number of humans in the world and our impact on the environment will overload the life support systems of the earth. The crude birth rate is the number of births in a year divided by the average population. A more accurate measure of growth is the general fertility rate, which takes into account the age structure and fecundity of the population. The crude birth rate minus the crude death rate gives the rate of natural increase. When this rate reaches a level at which people are just replacing themselves, zero population growth is achieved. In the more highly developed countries of the world, growth has slowed are even reversed in recent years so that without immigration from other areas, population would be declining. The change from high birth and death rates that accompanies in industrialization is called a demographic transition. Many developing nations have already begun this transition. Death rates have fallen, but birth rates remain high. Some demographers believe that as infant mortality drops and economic development progresses so that people in these countries can be sure of secure future, they will complete the transition to a stable population or a high standard living. While larger populations bring many problems, they also may be a valuable resource of energy, intelligence, and enterprise that will make it possible to overcome resource limitation problems. A social just view argues that a more equitable distribution of wealth might reduce both excess population growth and environmental degradation. We have many more options now for controlling fertility than were available

Modeling the pre-industrial roots of modern super-exponential population growth.

Science.gov (United States)

Stutz, Aaron Jonas

2014-01-01

To Malthus, rapid human population growth-so evident in 18th Century Europe-was obviously unsustainable. In his Essay on the Principle of Population, Malthus cogently argued that environmental and socioeconomic constraints on population rise were inevitable. Yet, he penned his essay on the eve of the global census size reaching one billion, as nearly two centuries of super-exponential increase were taking off. Introducing a novel extension of J. E. Cohen's hallmark coupled difference equation model of human population dynamics and carrying capacity, this article examines just how elastic population growth limits may be in response to demographic change. The revised model involves a simple formalization of how consumption costs influence carrying capacity elasticity over time. Recognizing that complex social resource-extraction networks support ongoing consumption-based investment in family formation and intergenerational resource transfers, it is important to consider how consumption has impacted the human environment and demography--especially as global population has become very large. Sensitivity analysis of the consumption-cost model's fit to historical population estimates, modern census data, and 21st Century demographic projections supports a critical conclusion. The recent population explosion was systemically determined by long-term, distinctly pre-industrial cultural evolution. It is suggested that modern globalizing transitions in technology, susceptibility to infectious disease, information flows and accumulation, and economic complexity were endogenous products of much earlier biocultural evolution of family formation's embeddedness in larger, hierarchically self-organizing cultural systems, which could potentially support high population elasticity of carrying capacity. Modern super-exponential population growth cannot be considered separately from long-term change in the multi-scalar political economy that connects family formation and

The Population Growth and Carrying Capacity in Semarang City

Science.gov (United States)

Hariyanto; Hadi, Sudharto P.; Buchori, Imam

2018-02-01

Population growth and development of city activities take some lands to carry them. As a result, land use competition happens among persons, society or sector. Land necessity for settlement, industry, or sector has taken over farm land, therefore farm land has been converted intensively and massively. Chronologically, population growth will cause land necessity increase. Unproductive land, especially farm land will be converted. Furthermore, farm land conversion will cause carrying capacity change. Carrying capacity has certain bio capacity. With the population growth, it will increase resource consumption; on the other side, farm land conversion will decrease carrying capacity. The objective of the study is to know about the influence of population growth towards carrying capacity (bio capacity) in Semarang city. Land consumption per capita is indeed influenced by city population, the higher the population is, the lower the land consumption per capita. With the population growth, it will influence carrying capacity. Carrying capacity here is the ratio of area to population. Analytical descriptive method is applied in the study with all sub-districts in Semarang city as the analysis unit. Population here is sub-district area and population per sub-district in Semarang city. Population growth data period is from 2000 until 2015. Main variables of the study are area per sub-district, population, population growth, carrying capacity. Result of the study shows significant influence of carrying capacity decrease, especially some outskirts in Semarang city. This condition happens because the outskirts in Semarang city tend to have dense population growth. Range of carrying capacity in Semarang city is from 0,007 to 0,117 of 0 to 1. Almost all sub-districts in Semarang city show miserable condition, except Mijen and Tugu. The conclusion of the study is that population will decrease carrying capacity. Therefore, the government should control population growth by paying

Making a stand: five centuries of population growth in colonizing populations of Pinus ponderosa.

Science.gov (United States)

Lesser, Mark R; Jackson, Stephen T

2012-05-01

The processes underlying the development of new populations are important for understanding how species colonize new territory and form viable long-term populations. Life-history-mediated processes such as Allee effects and dispersal capability may interact with climate variability and site-specific factors to govern population success and failure over extended time frames. We studied four disjunct populations of ponderosa pine in the Bighorn Basin of north-central Wyoming to examine population growth spanning more than five centuries. The study populations are separated from continuous ponderosa pine forest by distances ranging from 15 to >100 km. Strong evidence indicates that the initial colonizing individuals are still present, yielding a nearly complete record of population history. All trees in each population were aged using dendroecological techniques. The populations were all founded between 1530 and 1655 cal yr CE. All show logistic growth patterns, with initial exponential growth followed by a slowing during the mid to late 20th century. Initial population growth was slower than expectations from a logistic regression model at all four populations, but increased during the mid-18th century. Initial lags in population growth may have been due to strong Allee effects. A combination of overcoming Allee effects and a transition to favorable climate conditions may have facilitated a mid-18th century pulse in population growth rate.

Projections of highway vehicle population, energy demand, and CO{sub 2} emissions in India through 2040.

Energy Technology Data Exchange (ETDEWEB)

Arora, S.; Vyas, A.; Johnson, L.; Energy Systems

2011-02-22

This paper presents projections of motor vehicles, oil demand, and carbon dioxide (CO{sub 2}) emissions for India through the year 2040. The populations of highway vehicles and two-wheelers are projected under three different scenarios on the basis of economic growth and average household size in India. The results show that by 2040, the number of highway vehicles in India would be 206-309 million. The oil demand projections for the Indian transportation sector are based on a set of nine scenarios arising out of three vehicle-growth and three fuel-economy scenarios. The combined effects of vehicle-growth and fuel-economy scenarios, together with the change in annual vehicle usage, result in a projected demand in 2040 by the transportation sector in India of 404-719 million metric tons (8.5-15.1 million barrels per day). The corresponding annual CO{sub 2} emissions are projected to be 1.2-2.2 billion metric tons.

A stochastic population model to evaluate Moapa dace (Moapa coriacea) population growth under alternative management scenarios

Science.gov (United States)

Perry, Russell W.; Jones, Edward; Scoppettone, G. Gary

2015-07-14

The primary goal of this research project was to evaluate the response of Moapa dace (Moapa coriacea) to the potential effects of changes in the amount of available habitat due to human influences such as ground water pumping, barriers to movement, and extirpation of Moapa dace from the mainstem Muddy River. To understand how these factors affect Moapa dace populations and to provide a tool to guide recovery actions, we developed a stochastic model to simulate Moapa dace population dynamics. Specifically, we developed an individual based model (IBM) to incorporate the critical components that drive Moapa dace population dynamics. Our model is composed of several interlinked submodels that describe changes in Moapa dace habitat as translated into carrying capacity, the influence of carrying capacity on demographic rates of dace, and the consequent effect on equilibrium population sizes. The model is spatially explicit and represents the stream network as eight discrete stream segments. The model operates at a monthly time step to incorporate seasonally varying reproduction. Growth rates of individuals vary among stream segments, with growth rates increasing along a headwater to mainstem gradient. Movement and survival of individuals are driven by density-dependent relationships that are influenced by the carrying capacity of each stream segment.

Comparison of customised growth charts v. standard population

African Journals Online (AJOL)

pregnant diabetic population using population-based growth charts and customised growth charts. Methods. ... Of the patients, 44 had type 1, 66 type 2 and 173 gestational diabetes. The growth of .... with diabetic ketoacidosis, of whom one.

The Veteran Population Projection 2014

Data.gov (United States)

Department of Veterans Affairs — VetPop2014 is an actuarial projection model developed by the Office of the Actuary (OACT) for Veteran population projection from Fiscal Year FY2014 to FY2043. Using...

Is faster economic growth compatible with reductions in carbon emissions? The role of diminished population growth

Science.gov (United States)

Casey, Gregory; Galor, Oded

2017-01-01

We provide evidence that lower fertility can simultaneously increase income per capita and lower carbon emissions, eliminating a trade-off central to most policies aimed at slowing global climate change. We estimate the effect of lower fertility on carbon emissions, accounting for the fact that changes in fertility patterns affect carbon emissions through three channels: total population, the age structure of the population, and economic output. Our analysis proceeds in two steps. First, we estimate the elasticity of carbon emissions with respect to population and income per capita in an unbalanced yearly panel of cross-country data from 1950-2010. We demonstrate that the elasticity with respect to population is nearly seven times larger than the elasticity with respect to income per capita and that this difference is statistically significant. Thus, the regression results imply that 1% slower population growth could be accompanied by an increase in income per capita of nearly 7% while still lowering carbon emissions. In the second part of our analysis, we use a recently constructed economic-demographic model of Nigeria to estimate the effect of lower fertility on carbon emissions, accounting for the impacts of fertility on population growth, population age structure, and income per capita. We find that by 2100 C.E. moving from the medium to the low variant of the UN fertility projection leads to 35% lower yearly emissions and 15% higher income per capita. These results suggest that population policies could be part of the approach to combating global climate change.

The Growth of Older Inmate Populations: How Population Aging Explains Rising Age at Admission.

Science.gov (United States)

Luallen, Jeremy; Cutler, Christopher

2017-09-01

Older inmates are the fastest growing segment of the prison population; however, the reasons for this are not well understood. One explanation is that the general population is aging, driving prison age distributions to change. For this article, we study the role of population aging in prison growth by investigating how the baby boom phenomenon of post-World War II has contributed to the growth of older inmate populations. We identify the impact of population aging using simulation methods that explain prison growth as the combination of criminal justice processes. Overall, we find evidence that population aging has played a significant role in explaining the growth of older inmate populations, in particular among inmates aged between 50 and 64 years, contributing to as much as half of the observed increase in these groups since 2000. This finding stands in contrast to the notion that population aging has little explanatory power in describing the growth of prison populations and implies that older inmate groups are more sensitive to compositional changes in the general population. We argue that prediction-based modeling of prison growth should more seriously consider the impacts and consequences of demographic shifts among older prisoner populations. © The Author 2015. Published by Oxford University Press on behalf of The Gerontological Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

NIDI scenario. Strong population decline in China

OpenAIRE

de Beer, J.A.A.

2016-01-01

United Nations projections assume that by the end of this century one third of the world population will live in India, China or Nigeria. While population growth in India will slow down and the population size of China will decline, population growth in Nigeria will accelerate. A new NIDI scenario projects less population growth in Nigeria and sharp population decline in China.

Demographic models and IPCC climate projections predict the decline of an emperor penguin population

Science.gov (United States)

Jenouvrier, Stéphanie; Caswell, Hal; Barbraud, Christophe; Holland, Marika; Strœve, Julienne; Weimerskirch, Henri

2009-01-01

Studies have reported important effects of recent climate change on Antarctic species, but there has been to our knowledge no attempt to explicitly link those results to forecasted population responses to climate change. Antarctic sea ice extent (SIE) is projected to shrink as concentrations of atmospheric greenhouse gases (GHGs) increase, and emperor penguins (Aptenodytes forsteri) are extremely sensitive to these changes because they use sea ice as a breeding, foraging and molting habitat. We project emperor penguin population responses to future sea ice changes, using a stochastic population model that combines a unique long-term demographic dataset (1962–2005) from a colony in Terre Adélie, Antarctica and projections of SIE from General Circulation Models (GCM) of Earth's climate included in the most recent Intergovernmental Panel on Climate Change (IPCC) assessment report. We show that the increased frequency of warm events associated with projected decreases in SIE will reduce the population viability. The probability of quasi-extinction (a decline of 95% or more) is at least 36% by 2100. The median population size is projected to decline from ≈6,000 to ≈400 breeding pairs over this period. To avoid extinction, emperor penguins will have to adapt, migrate or change the timing of their growth stages. However, given the future projected increases in GHGs and its effect on Antarctic climate, evolution or migration seem unlikely for such long lived species at the remote southern end of the Earth. PMID:19171908

Poverty-led higher population growth in Bangladesh.

Science.gov (United States)

Nakibullah, A; Rahman, A

1996-01-01

This article discusses the issue whether population growth is exogenous or endogenous in the economic development of Bangladesh. Overpopulation adversely affects food supplies, foreign exchange, and human resources. Moreover, it depresses savings per capita and retards growth of physical capital per labor. Underdeveloped countries, like Bangladesh, are faced with the problem of allocating resources between infrastructure, education, and health service that are essential for human capital development and population control measures. With this, determination whether fertility is exogenous or endogenous is important for policy purposes in the context of Bangladesh. Results showed that there is a correlation between population growth and real gross domestic products per capita. Based on Granger causality test, population growth is endogenous in the development process of Bangladesh and its overpopulation is due to poverty. Thus, there is a need for appropriate policy to take measures to improve human capital and decrease fertility rates.

Growth and Project Finance in the Least Developed Countries

DEFF Research Database (Denmark)

la Cour, Lisbeth F.; Müller, Jennifer

2014-01-01

for economic growth in LDCs. We find that a higher regulatory quality, lower government consumption and a higher level of education helps increase growth. The significance of these variables are, however, not as consistently robust as the results for project finance.......This article examines the effects of project finance on economic growth in the least developed countries (LDC). Inspired by the neoclassical growth model we set up an econometric model to estimate the effects of project finance for a sample consisting of 38 of the least developed countries using...... data from the period 1994-2007. The results of our study suggest, that project finance has a significant positive effect on economic growth and therefore constitute an important source of financing in the selected set of countries. Additionally, the project sheds light on other factors of importance...

Population growth and food supply in sub-Saharan Africa.

Science.gov (United States)

Meerman, J; Cochrane, S H

1982-09-01

It is argued in this article that sub-Saharan Africa, given its present institutions and endowments of capital and technology, is already dangerously close to overpopulation. The rapid growth of its population projected for the next decades will greatly increase human misery and depress economic development. Specifically, rapid population growth will have disastrous effects on the region's ability to increase exports and provide people with food. There must be a search for new ways in which these effects could be mitigated. In sub-Saharan Africa fertility either continues to be very high or is increasing, in part due to some decline in traditional practices that reduce fertility, such as prolonged breastfeeding. This situation and the expectation of declining mortality imply that African population growth may increase further. Currently, population in sub-Saharan Africa is about half that of India and a third of China. There are 2 main reasons why reduced fertility in the next few decades is unlikely in sub-Saharan Africa as a whole: Africa has low literacy, high infant and child mortality, and low urbanization; and average African fertility rates may even increase for the next 20 years or so. The question that arises is what are the implications of continuing and rapid population growth for the African food supply. The region's cereal production is largely restricted to 4 grains, i.e., millet, sorghum, maize, and rice. The volume of grain production is less, by weight, than 60% of the production of roots and tubers. There are 2 main differences between the output of these crops in sub-Saharan Africa and the rest of the world: yields/hectare are lower in Africa than in elsewhere; and yields have generally been decreasing or largely constant in Africa. The low productivity has several causes. Today, population pressure has brought diminishing returns to traditional agriculture in much of the Sahel and the savanna, in parts of East Africa, Southern Africa, and parts

Projection of Chinese motor vehicle growth, oil demand, and CO{sub 2}emissions through 2050.

Energy Technology Data Exchange (ETDEWEB)

Wang, M.; Huo, H.; Johnson, L.; He, D.

2006-12-20

As the vehicle population in China increases, oil consumption and carbon dioxide (CO{sub 2}) emissions associated with on-road transportation are rising dramatically. During this study, we developed a methodology to project trends in the growth of the vehicle population, oil demand, and CO{sub 2} emissions associated with on-road transportation in China. By using this methodology, we projected--separately--the number of highway vehicles, motorcycles, and rural vehicles in China through 2050. We used three scenarios of highway vehicle growth (high-, mid-, and low-growth) to reflect patterns of motor vehicle growth that have occurred in different parts of the world (i.e., Europe and Asia). All are essentially business-as-usual scenarios in that almost none of the countries we examined has made concerted efforts to manage vehicle growth or to offer serious alternative transportation means to satisfy people's mobility needs. With this caveat, our projections showed that by 2030, China could have more highway vehicles than the United States has today, and by 2035, it could have the largest number of highway vehicles in the world. By 2050, China could have 486-662 million highway vehicles, 44 million motorcycles, and 28 million rural vehicles. These numbers, which assume essentially unmanaged vehicle growth, would result in potentially disastrous effects on the urban infrastructure, resources, and other social and ecological aspects of life in China. We designed three fuel economy scenarios, from conservative to aggressive, on the basis of current policy efforts and expectations of near-future policies in China and in developed countries. It should be noted that these current and near-future policies have not taken into consideration the significant potential for further fuel economy improvements offered by advanced technologies such as electric drive technologies (e.g., hybrid electric vehicles and fuel-cell vehicles). By using vehicle growth projections and

Environmental degradation, energy consumption, population growth ...

African Journals Online (AJOL)

Based on the result, there is no evidence of unidirectional causality running from CO2 emissions and energy consumption to economic growth and strong unidirectional causality running from CO2 emissions, energy consumption and economic growth to population growth was found. The long run and short run estimates ...

Hispanic Population Growth and Rural Income Inequality

Science.gov (United States)

Parrado, Emilio A.; Kandel, William A.

2010-01-01

We analyze the relationship between Hispanic population growth and changes in U.S. rural income inequality from 1990 through 2000. Applying comparative approaches used for urban areas we disentangle Hispanic population growth's contribution to inequality by comparing and statistically modeling changes in the family income Gini coefficient across…

Growth rate, population entropy, and perturbation theory.

OpenAIRE

Demetrius, L.

1989-01-01

This paper is concerned with the connection between two classes of population variables: measures of population growth rate—the Malthusian parameter, the net reproduction rate, the gross reproduction rate, and the mean life expectancy; and measures of demographic heterogeneity—population entropy. It is shown that the entropy functions predict the response of the growth rate parameters to perturbations in the age-specific fecundity and mortality schedule. These results are invoked to introduce...

Projections of the Size and Composition of the U.S. Population: 2014 to 2060. Population Estimates and Projections. Current Population Reports. P25-1143

Science.gov (United States)

Colby, Sandra L.; Ortman, Jennifer M.

2015-01-01

Between 2014 and 2060, the U.S. population is projected to increase from 319 million to 417 million, reaching 400 million in 2051. The U.S. population is projected to grow more slowly in future decades than in the recent past, as these projections assume that fertility rates will continue to decline and that there will be a modest decline in the…

Population Growth and Poverty in the Developing World.

Science.gov (United States)

Birdsall, Nancy

1980-01-01

The link between rapid population growth and the absolute poverty which currently afflicts 780 million people in developing countries (excluding China and other centrally planned economies) is examined. As a result of rapid population growth, many countries suffer slow per capita income growth, a lack of progress in reducing income inequality, and…

Impact of population growth and population ethics on climate change mitigation policy.

Science.gov (United States)

Scovronick, Noah; Budolfson, Mark B; Dennig, Francis; Fleurbaey, Marc; Siebert, Asher; Socolow, Robert H; Spears, Dean; Wagner, Fabian

2017-11-14

Future population growth is uncertain and matters for climate policy: higher growth entails more emissions and means more people will be vulnerable to climate-related impacts. We show that how future population is valued importantly determines mitigation decisions. Using the Dynamic Integrated Climate-Economy model, we explore two approaches to valuing population: a discounted version of total utilitarianism (TU), which considers total wellbeing and is standard in social cost of carbon dioxide (SCC) models, and of average utilitarianism (AU), which ignores population size and sums only each time period's discounted average wellbeing. Under both approaches, as population increases the SCC increases, but optimal peak temperature decreases. The effect is larger under TU, because it responds to the fact that a larger population means climate change hurts more people: for example, in 2025, assuming the United Nations (UN)-high rather than UN-low population scenario entails an increase in the SCC of 85% under TU vs. 5% under AU. The difference in the SCC between the two population scenarios under TU is comparable to commonly debated decisions regarding time discounting. Additionally, we estimate the avoided mitigation costs implied by plausible reductions in population growth, finding that large near-term savings ($billions annually) occur under TU; savings under AU emerge in the more distant future. These savings are larger than spending shortfalls for human development policies that may lower fertility. Finally, we show that whether lowering population growth entails overall improvements in wellbeing-rather than merely cost savings-again depends on the ethical approach to valuing population. Copyright © 2017 the Author(s). Published by PNAS.

Impact of Population Growth and Climate Change on the Freshwater Resources of Lamu Island, Kenya

Directory of Open Access Journals (Sweden)

Cornelius Okello

2015-03-01

Full Text Available Demand for freshwater is rising with factors, such as population growth, land use change and climate variations, rendering water availability in the future uncertain. Groundwater resources are being increasingly exploited to meet this growing demand. The aim of this study is to identify the influence of population growth induced by land use change and climate change on the future state of freshwater resources of Lamu Island in Kenya where a major port facility is under construction. The results of this study show that the “no industrial development” population scenario (assuming the port was not constructed would be expected to reach ~50,000 people by 2050, while the projected population upon completion is expected to reach 1.25 million in the same year when the Lamu Port-South Sudan-Ethiopia Transport Corridor Program (LAPSSET port reaches its full cargo-handling capacity. The groundwater abstraction in 2009 was 0.06 m3 daily per capita, while the demand is expected to raise to 0.1 m3 by 2050 according to the “LAPSSET development” projection. The modelling results show that the Shela aquifer in Lamu, which is the main source of water on the island, will not experience stress by 2065 for the “no industrial development” population scenario, whereas for the “LAPSSET development projection” population scenario, it will occur sooner (between 2020 and 2028. The modelling results show that the Representative Concentration Pathways (RCP climate change scenarios will have a smaller impact on the effective water volume reserves than Special Report on Emissions Scenarios (SRES for the “no industrial development”, while the impact is expected to be similar for the “LAPSSET development”, suggesting that population growth exacerbated by land use change will be a more significant driving force than climate change in affecting freshwater availability.

Urban population and economic growth: South Asia perspective

Directory of Open Access Journals (Sweden)

Sandip Sarker

2016-07-01

Full Text Available Previously economic growth was generally discussed in terms of foreign direct investment (FDI, educational growth, savings, investments, inflation as well as trade openness of a nation. Very recently it has been identified that population is one of the major determinants of economic growth of a nation. In the recent years, the study of urbanization has gained a matter of concern in developing countries as it has been recognized as part of a larger process of economic development which is affecting developing countries. South Asian countries are one of the emerging economics and growing at a faster rate over the past few years. At the same time, population of South Asia is growing at a significant rate. Therefore the study has attempted to identify the causal relationship between urban population and economic growth in South Asia using a panel data analysis. The study makes use of the Augmented Dickey-Fuller (ADF and Phillips-Perron (PP, Pesaran as well as Fisher methods for panel unit root test. The panel Pedroni cointegration test suggests that there is long run relationship between the variables. The further panel Vector Error Correction Model (VECM suggests that there is long run causality running from urban population growth to economic growth in South Asia. The study concludes that the growth of urban population can have significant impact on economic growth in South Asia in the long run.

Growth and project finance in the least developed countries

OpenAIRE

Lisbeth F. la Cour; Jennifer Müller

2014-01-01

This article examines the effects of project finance on economic growth in the least developed countries (LDC). Inspired by the neoclassical growth model we set up an econometric model to estimate the effects of project finance for a sample consisting of 38 of the least developed countries using data from the period 1994-2007. The results of our study suggest, that project finance has a significant positive effect on economic growth and therefore constitute an important source of ...

Implications of population growth for Nigeria's development | Fan ...

African Journals Online (AJOL)

Nigeria's population that was 16 million in 1911 is about 140 million today. Attention invariably turns to the implications of this growth to the qualities of life for her inhabitants. The paper notes that high birth rate, low death rate and migration are the sources of the high population growth in Nigeria. The population then ...

Metropolitan migration and population growth in selected developing countries.

Science.gov (United States)

1983-01-01

The purpose of this article is to estimate the components of metropolitan population growth in selected developing countries during 1960-1970 period. The study examines population growth in 26 cities: 5 are in Africa, 8 in Asia, and 13 in Latin America, using data from national census publications. These cities in general are the political capitals of their countries, but some additional large cities were selected in Brazil, Mexico, and South Africa. All cities, at the beginning of the 1960-1970 decade had over 500,000 population; Accra, the only exception, reached this population level during the 1960s. Some cities had over 4 million residents in 1970. Net migration contributed about 37% to total metropolitan population growth; the remainder of the growth is attributable to natural increase. Migration has a much stronger impact on metropolitan growth than suggested by the above figure: 1) Several metropolitan areas, for various reasons, are unlikely to receive many migrants; without those cities, the share of metropolitan growth from net migration is 44%. 2) Estimates of the natural increase of migrants after their arrival in the metropolitan areas, when added to migration itself, changes the total contribution of migration to 49% in some metropolitan areas. 3) Even where net migration contributes a smaller proportion to metropolitan growth than natural increase, the rates of net migration are generally high and should be viewed in the context of rapid metropolitan population growth from natural increase alone. Finally, the paper also compares the components of metropolitan growth with the components of growth in the remaining urban areas. The results show that the metropolitan areas, in general, grow faster than the remaining urban areas, and that this more rapid growth is mostly due to a higher rate of net migration. Given the significance of migration for metropolitan growth, further investigations of the effects of these migration streams, particularly with

Population growth, accessibility spillovers and persistent borders: Historical growth in West-European municipalities.

Science.gov (United States)

Jacobs-Crisioni, Chris; Koomen, Eric

2017-06-01

Lack of cross-border transport supply has repeatedly been blamed for the fact that national borders limit spatial interaction and, consequently, the growth of border regions. This study applies an accessibility approach to investigate for most municipalities in ten countries in mainland West Europe if foreign transport supply is lagging behind, and if population growth in these municipalities has been affected by the limits that national borders have imposed on market access. To do so, data describing historical population changes and road networks between 1961 and 2011 have been used. The results show that in the study area, cross-border transport accessibility was not at a disadvantage in 1961 and has since then grown even more than domestic accessibility. However, municipal population growth has depended almost exclusively on domestic market access. Processes of economic international integration in the study area are found to coincide with the growth of cross-border accessibility, but do not have a clear coincidence with the effects of cross-border accessibility on population growth.

The old age security hypothesis and optimal population growth.

Science.gov (United States)

Bental, B

1989-03-01

The application of the Samuelson-Diamond overlapping generations framework to the old age security hypothesis indicates that government intervention schemes can influence the relationship between population growth and capital accumulation. The most direct means of optimizing population growth is through taxes or subsidies that relate to the intergenerational transfer of wealth. A pay-as-you-go social security scheme, in which payment is predicated on the number of children the receiver has and is financed by taxes levied on the working population, emerges as the most likely intervention to produce the optimal steady state equilibrium. This system is able to correct any distortions the private sector may build into it. In contrast, a child support system, in which the government subsidizes or taxes workers according to their family size, can guarantee the optimal capital:labor ratio but not the optimal population growth rate. Thus, if the government seeks to decrease the population growth rate, the appropriate intervention is to levy a lump-sum social-security tax on workers and transfer the revenues to the old; the direction should be reversed if the goal is to increase population growth. Another alternative, a lump sum social security system, can guarantee optimal population growth but not a desirable capital:labor ratio. Finally, the introduction of money as a valued commodity into an economy with a high capital:labor ratio will also serve to decrease the population growth rate and solve the intergenerational transfer problem through the private sector without any need for government intervention.

Integrating sustainable growth into export pipeline projects

International Nuclear Information System (INIS)

Jeniffer, Barringer; William, Lukens; Patricia, Wild

2002-01-01

Full text: Sustainable growth in the energy industry is rapidly expanding beyond the conceptual stage. Policies addressing the three principles of Sustainable Development are being established and strategies to execute these policies are being developed and implemented in the field. Conoco is developing a strong corporate culture around sustainable growth; and, pipeline systems play a vital role in delivering the triple bottom line results for our stake holders. This paper will highlight some of the key focal points by Conoco Inc., in each phase of pipeline project development, execution, and operation to make pipeline projects a contributor to Conoco's sustainable growth success, and shares some lessons learned

Review on Population Projection Methodology for Radiological Dose Assessment

Energy Technology Data Exchange (ETDEWEB)

Jang, M. S.; Kang, H. S.; Kim, S. R. [NESS, Daejeon (Korea, Republic of); Hwang, W. T. [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Yang, Y. H. [KHNP, Daejeon (Korea, Republic of)

2015-05-15

Radiation environment report (RER), one of the essential documents in plant operating license or continuous operation license, includes population projection. Population estimates are utilized in determining the collective dose at the operation or restart time of nuclear power plant. Many population projection models are suggested and also under development. We carried out the sensitivity analysis on various population projection models to Daejeon city as a target. Daejeon city showed the increase or decrease in the cross-sectional population, because of the development of Sejong city, Doan new town and etc. We analyzed the population of Daejeon city using statistical ARIMA model and various simple population projection models. It is important to determine the population limit in Modified exponential model but it is not easy. Therefore, the various properties of the area such as the decrease and increase of population, new town development plan, social and natural environment change and etc., should be carefully reviewed to estimate the future population of any area.

Review on Population Projection Methodology for Radiological Dose Assessment

International Nuclear Information System (INIS)

Jang, M. S.; Kang, H. S.; Kim, S. R.; Hwang, W. T.; Yang, Y. H.

2015-01-01

Radiation environment report (RER), one of the essential documents in plant operating license or continuous operation license, includes population projection. Population estimates are utilized in determining the collective dose at the operation or restart time of nuclear power plant. Many population projection models are suggested and also under development. We carried out the sensitivity analysis on various population projection models to Daejeon city as a target. Daejeon city showed the increase or decrease in the cross-sectional population, because of the development of Sejong city, Doan new town and etc. We analyzed the population of Daejeon city using statistical ARIMA model and various simple population projection models. It is important to determine the population limit in Modified exponential model but it is not easy. Therefore, the various properties of the area such as the decrease and increase of population, new town development plan, social and natural environment change and etc., should be carefully reviewed to estimate the future population of any area

Contribution of population growth to per capita income and sectoral output growth in Japan, 1880-1970.

Science.gov (United States)

Yamaguchi, M; Kennedy, G

1984-09-01

The authors measured the positive and negative contributions of population and labor force growth to the growth of per capita income and sectoral output in Japan in the 1880-1970 period. A 2-sector growth accounting model that treats population and labor growth as separate variables was used. 3 alternative methods were used: the Residual method, the Verdoorn method, and the factor augmenting rate method. The total contribution of population cum labor growth to per capita income growth tended to be negative in the 1880-1930 period and positive in the 1930-40 and 1950-70. Over the 1880-1970 period as a whole, population cum labor growth made a positive contribution to per capita income growth under the Residual method (0.35%/year), the factor augmenting rate method (0.29%/year), and the Verdoorn method (0.01%/year). In addition, population cum labor growth contributed positively to sectoral output growth. The average contribution to agricultural output growth ranged from 1.03% (Verdoorn) - 1.46%/year (factor augmenting rate), while the average contribution to nonagricultural output growth ranged from 1.22% (Verdoorn) - 1.60%/year (Residual). Although these results are dependent on the model used, the fact that all 3 methods yielded consistent results suggests that population cum labor growth did make a positive contribution to per capita income and sectoral output growth in Japan. These findings imply that in economies where the rate of technical change in agricultural and nonagricultural sectors exceeds population growth, policies that reduce agricultural elasticities may be preferable; on the other hand, policies that reduce agricultural elasticities are to be avoided in economies with low rates of technical change. Moreover, in the early stages of economic development, policies that increase agricultural income and price elasticities should be considered.

Beyond the Mean: Sensitivities of the Variance of Population Growth.

Science.gov (United States)

Trotter, Meredith V; Krishna-Kumar, Siddharth; Tuljapurkar, Shripad

2013-03-01

Populations in variable environments are described by both a mean growth rate and a variance of stochastic population growth. Increasing variance will increase the width of confidence bounds around estimates of population size, growth, probability of and time to quasi-extinction. However, traditional sensitivity analyses of stochastic matrix models only consider the sensitivity of the mean growth rate. We derive an exact method for calculating the sensitivity of the variance in population growth to changes in demographic parameters. Sensitivities of the variance also allow a new sensitivity calculation for the cumulative probability of quasi-extinction. We apply this new analysis tool to an empirical dataset on at-risk polar bears to demonstrate its utility in conservation biology We find that in many cases a change in life history parameters will increase both the mean and variance of population growth of polar bears. This counterintuitive behaviour of the variance complicates predictions about overall population impacts of management interventions. Sensitivity calculations for cumulative extinction risk factor in changes to both mean and variance, providing a highly useful quantitative tool for conservation management. The mean stochastic growth rate and its sensitivities do not fully describe the dynamics of population growth. The use of variance sensitivities gives a more complete understanding of population dynamics and facilitates the calculation of new sensitivities for extinction processes.

Economic consequences of population size, structure and growth.

Science.gov (United States)

Lee, R

1983-01-01

There seems to be 4 major approaches to conceptualizing and modeling demographic influences on economic and social welfare. These approaches are combined in various ways to construct richer and more comprehensive models. The basic approaches are: demographic influences on household or family behavior; population growth and reproducible capital; population size and fixed factors; and population and advantages of scale. These 4 models emphasize the supply side effects of population. A few of the ways in which these theories have been combined are sketched. Neoclassical growth models often have been combined with age distributed populations of individuals (or households), assumed to pursue optimal life cycle consumption and saving. In some well known development models, neoclassical growth models for the modern sector are linked by labor markets and migration to fixed factor (land) models of the traditional (agricultural) sector. A whole series of macro simulation models for developed and developing countries was based on single sector neoclassical growth models with age distributed populations. Yet, typically the household level foundations of assumed age distribution effects were not worked out. Simon's (1977) simulation models are in a class by themselves, for they are the only models that attempt to incorporate all the kinds of effects discussed. The economic demography of the individual and family cycle, as it is affected by regimes of fertility, mortality, and nuptiality, taken as given, are considered. The examination touches on many of the purported consequences of aggregate population growth and age composition, since so many of these are based implicitly or explicitly on assertions about micro level behavior. Demographic influences on saving and consumption, on general labor supply and female labor supply, and on problems of youth and old age dependency frequently fall in this category. Finally, attention is focused specifically on macro economic issues in

Environmental impact of population growth

Science.gov (United States)

Naylor, Rosamond; Matson, Pamela

Earth's population currently numbers 5.4 billion; even given optimistic assumptions for reduction in growth rates, the number will double by the middle of the next century with most of the increase in the developing countries. Rapid population growth in the developing world raises the fundamental dilemma of how to alleviate chronic hunger and poverty in the short run while preserving the atmosphere and ecosystem services required for long-term human and biospheric sustenance. This dilemma, and the compromises required to solve it, were discussed by twenty-five researchers from five countries at the Aspen Global Change Institute 1992 Summer Science Session III, Food, Conservation, and Global Environmental Change: Is Compromise Possible?, held from August 16 to 28, in Aspen, Colo.

Effects of climate change on long-term population growth of pronghorn in an arid environment

Science.gov (United States)

Gedir, Jay V.; Cain, James W.; Harris, Grant; Turnbull, Trey T.

2015-01-01

Climate often drives ungulate population dynamics, and as climates change, some areas may become unsuitable for species persistence. Unraveling the relationships between climate and population dynamics, and projecting them across time, advances ecological understanding that informs and steers sustainable conservation for species. Using pronghorn (Antilocapra americana) as an ecological model, we used a Bayesian approach to analyze long-term population, precipitation, and temperature data from 18 populations in the southwestern United States. We determined which long-term (12 and 24 months) or short-term (gestation trimester and lactation period) climatic conditions best predicted annual rate of population growth (λ). We used these predictions to project population trends through 2090. Projections incorporated downscaled climatic data matched to pronghorn range for each population, given a high and a lower atmospheric CO2 concentration scenario. Since the 1990s, 15 of the pronghorn populations declined in abundance. Sixteen populations demonstrated a significant relationship between precipitation and λ, and in 13 of these, temperature was also significant. Precipitation predictors of λ were highly seasonal, with lactation being the most important period, followed by early and late gestation. The influence of temperature on λ was less seasonal than precipitation, and lacked a clear temporal pattern. The climatic projections indicated that all of these pronghorn populations would experience increased temperatures, while the direction and magnitude of precipitation had high population-specific variation. Models predicted that nine populations would be extirpated or approaching extirpation by 2090. Results were consistent across both atmospheric CO2 concentration scenarios, indicating robustness of trends irrespective of climatic severity. In the southwestern United States, the climate underpinning pronghorn populations is shifting, making conditions increasingly

Volatility and Growth in Populations of Rural Associations

Science.gov (United States)

Wollebaek, Dag

2010-01-01

This article uses unique community-level data aggregated from censuses of associations to analyze growth and volatility in rural populations of grassroots associations. A qualitative comparative analysis (QCA) shows that the two main paths to growth were (1) centralization in polycephalous (multicentered) municipalities and (2) population growth…

Adapting to Population Growth: The Evolutionary Alternative to Malthus

OpenAIRE

Axel Kristinsson; Árni Daníel Júlíusson

2016-01-01

A long-standing debate on the dynamics of population growth in human history has become polarized between a Malthusian stance and a Boserupian one. The former tends to view population growth as limited by carrying capacity, dependent on environment and technology, whereas the latter sees population growth itself as a major inducement to social, economic and technological developments. In this paper the authors experiment with approaching this debate by using recent developments in evolutionar...

The end of world population growth

NARCIS (Netherlands)

Lutz, W; Sanderson, W; Scherbov, S

2001-01-01

There has been enormous concern about the consequences of human population growth for the environment and for social and economic development. But this growth is likely to come to an end in the foreseeable future. Improving on earlier methods of probabilistic forecasting(1), here we show that there

Rapid Population Growth-Cause or Result of Global Problems?

Science.gov (United States)

Schwartz, Richard H.

Explosive population growth is a symptom of the world's unjust and inequitable social, political, and economic conditions. The current rate of growth is staggering, particularly in the cities of the underdeveloped countries. While some progress has been made in slowing population growth, several factors still contribute to its momentum. One of…

Economic analyses of rapid population growth.

Science.gov (United States)

Birdsall, N

1989-01-01

"Discussion of the macroeconomic consequences of rapid population growth is organized into three schools: pessimists, optimists, and the recent revisionists. For the revisionists, differing views are presented about the pervasiveness and relevance of market failures, such as the negative externalities of childbearing, and about the ability of families and institutions to adjust rapidly to changes brought on by rapid population growth. A welfare economics approach is used to review the merits of various public policies to reduce fertility, including public financing of family planning services and taxes and incentives associated with childbearing." The focus is on developing countries. excerpt

7 CFR 1948.78 - Growth management and housing planning projects.

Science.gov (United States)

2010-01-01

... 7 Agriculture 13 2010-01-01 2009-01-01 true Growth management and housing planning projects. 1948... Impacted Area Development Assistance Program § 1948.78 Growth management and housing planning projects. (a) Existing plans for growth management and housing may be used to meet the planning requirements of this...

Diet quality limits summer growth of field vole populations.

Directory of Open Access Journals (Sweden)

Kristian M Forbes

Full Text Available Marked variation occurs in both seasonal and multiannual population density peaks of northern European small mammal species, including voles. The availability of dietary proteins is a key factor limiting the population growth of herbivore species. The objective of this study is to investigate the degree to which protein availability influences the growth of increasing vole populations. We hypothesise that the summer growth of folivorous vole populations is positively associated with dietary protein availability. A field experiment was conducted over a summer reproductive period in 18 vegetated enclosures. Populations of field voles (Microtus agrestis were randomised amongst three treatment groups: 1 food supplementation with ad libitum high protein (30% dry weight pellets, 2 food supplementation with ad libitum low protein (1% dry weight; both supplemented foods had equivalent energy content pellets, and 3 control (no food supplementation, n = 6 per treatment. Vole density, survival, demographic attributes and condition indicators were monitored with live-trapping and blood sampling. Highest final vole densities were attained in populations that received high protein supplementation and lowest in low protein populations. Control populations displayed intermediate densities. The survival rate of voles was similar in all treatment groups. The proportion of females, and of those that were pregnant or lactating, was highest in the high protein supplemented populations. This suggests that variation in reproductive, rather than survival rates of voles, accounted for density differences between the treatment groups. We found no clear association between population demography and individual physiological condition. Our results demonstrate that dietary protein availability limits vole population growth during the summer growing season. This suggests that the nutritional quality of forage may be an underestimated source of interannual variation in the

Human Capital, Population Growth and Economic Development: Beyond Correlations

OpenAIRE

Rosenzweig, Mark R.

1987-01-01

Empirical evidence on three assertions commonly-made by population policy advocates about the relationships among population growth, human capital formation and economic development is discussed and evaluated in the light of economic-biological models of household behavior and of its relevance to population policy. The three assertions are that (a) population growth and human capital investments jointly reflect and respond to changes in the economic environment, (b) larger families directly i...

Lebensraum: paradoxically, population growth may eventually end wars.

Science.gov (United States)

Simon, J L

1989-03-01

Population growth may progressively reduce 1 of the motives for making war. Namely, population growth threatens shortages of resources, and especially land. Impending shortages cause a search for ways to mitigate the shortages. The discoveries eventually produce greater availability of resources than if population growth and pressure on resources had never occurred. The argument runs as follows: 1) Rhetoric about resources scarcity induced by population density has often contributed to international conflict, even if economics has not been the main motive in making war. 2) In the pre-modern era, war to obtain land and other resources may sometimes have been an economically sound policy. 3) Politicians and others in industrially developed nations believe resources may still be a casus belli. 4) Land and other productive resources are no longer worth acquiring at the cost of war.

Population growth of Yellowstone grizzly bears: Uncertainty and future monitoring

Science.gov (United States)

Harris, R.B.; White, Gary C.; Schwartz, C.C.; Haroldson, M.A.

2007-01-01

Grizzly bears (Ursus arctos) in the Greater Yellowstone Ecosystem of the US Rocky Mountains have recently increased in numbers, but remain vulnerable due to isolation from other populations and predicted reductions in favored food resources. Harris et al. (2006) projected how this population might fare in the future under alternative survival rates, and in doing so estimated the rate of population growth, 1983–2002. We address issues that remain from that earlier work: (1) the degree of uncertainty surrounding our estimates of the rate of population change (λ); (2) the effect of correlation among demographic parameters on these estimates; and (3) how a future monitoring system using counts of females accompanied by cubs might usefully differentiate between short-term, expected, and inconsequential fluctuations versus a true change in system state. We used Monte Carlo re-sampling of beta distributions derived from the demographic parameters used by Harris et al. (2006) to derive distributions of λ during 1983–2002 given our sampling uncertainty. Approximate 95% confidence intervals were 0.972–1.096 (assuming females with unresolved fates died) and 1.008–1.115 (with unresolved females censored at last contact). We used well-supported models of Haroldson et al. (2006) and Schwartz et al. (2006a,b,c) to assess the strength of correlations among demographic processes and the effect of omitting them in projection models. Incorporating correlations among demographic parameters yielded point estimates of λ that were nearly identical to those from the earlier model that omitted correlations, but yielded wider confidence intervals surrounding λ. Finally, we suggest that fitting linear and quadratic curves to the trend suggested by the estimated number of females with cubs in the ecosystem, and using AICc model weights to infer population sizes and λ provides an objective means to monitoring approximate population trajectories in addition to demographic

Migration, urban population growth and regional disparity in China

OpenAIRE

Renard, Mary-Françoise; Xu, Zelai; Zhu, Nong

2011-01-01

The main objective of this paper is to study the determinants of city population growth in China during the 1990s', as well as the determinants of migrations towards cities, which constitutes the main source of urban population growth in this period. A second objective is to identify regional differences in the urban growth and migrations, that is, whether urban growth and migration patterns are different between coastal and inland provinces. Additionally, we are interested in the differences...

Growth strategy of heterotrophic bacterial population along successional sequence on spoil of brown coal colliery substrate

Czech Academy of Sciences Publication Activity Database

Krištůfek, Václav; Elhottová, Dana; Chroňáková, Alica; Dostálková, I.; Picek, T.; Kalčík, Jiří

2005-01-01

Roč. 50, č. 5 (2005), s. 427-435 ISSN 0015-5632 R&D Projects: GA ČR(CZ) GA526/03/1259 Institutional research plan: CEZ:AV0Z60660521 Keywords : growth strategy * heterotrophic bacterial population * brown coal colliery spoil Subject RIV: EH - Ecology, Behaviour Impact factor: 0.918, year: 2005

Habitat-specific population growth of a farmland bird.

Directory of Open Access Journals (Sweden)

Debora Arlt

Full Text Available BACKGROUND: To assess population persistence of species living in heterogeneous landscapes, the effects of habitat on reproduction and survival have to be investigated. METHODOLOGY/PRINCIPAL FINDINGS: We used a matrix population model to estimate habitat-specific population growth rates for a population of northern wheatears Oenanthe oenanthe breeding in farmland consisting of a mosaic of distinct habitat (land use types. Based on extensive long-term data on reproduction and survival, habitats characterised by tall field layers (spring- and autumn-sown crop fields, ungrazed grasslands displayed negative stochastic population growth rates (log lambda(s: -0.332, -0.429, -0.168, respectively, that were markedly lower than growth rates of habitats characterised by permanently short field layers (pastures grazed by cattle or horses, and farmyards, log lambda(s: -0.056, +0.081, -0.059. Although habitats differed with respect to reproductive performance, differences in habitat-specific population growth were largely due to differences in adult and first-year survival rates, as shown by a life table response experiment (LTRE. CONCLUSIONS/SIGNIFICANCE: Our results show that estimation of survival rates is important for realistic assessments of habitat quality. Results also indicate that grazed grasslands and farmyards may act as source habitats, whereas crop fields and ungrazed grasslands with tall field layers may act as sink habitats. We suggest that the strong decline of northern wheatears in Swedish farmland may be linked to the corresponding observed loss of high quality breeding habitat, i.e. grazed semi-natural grasslands.

Population growth, human development, and deforestation in biodiversity hotspots.

Science.gov (United States)

Jha, S; Bawa, K S

2006-06-01

Human population and development activities affect the rate of deforestation in biodiversity hotspots. We quantified the effect of human population growth and development on rates of deforestation and analyzed the relationship between these causal factors in the 1980s and 1990s. We compared the averages of population growth, human development index (HDI, which measures income, health, and education), and deforestation rate and computed correlations among these variables for countries that contain biodiversity hotspots. When population growth was high and HDI was low there was a high rate of deforestation, but when HDI was high, rate of deforestation was low, despite high population growth. The correlation among variables was significant for the 1990s but not for the 1980s. The relationship between population growth and HDI had a regional pattern that reflected the historical process of development. Based on the changes in HDI and deforestation rate over time, we identified two drivers of deforestation: policy choice and human-development constraints. Policy choices that disregard conservation may cause the loss of forests even in countries that are relatively developed. Lack of development in other countries, on the other hand, may increase the pressure on forests to meet the basic needs of the human population. Deforestation resulting from policy choices may be easier to fix than deforestation arising from human development constraints. To prevent deforestation in the countries that have such constraints, transfer of material and intellectual resources from developed countries may be needed. Popular interest in sustainable development in developed countries can facilitate the transfer of these resources.

Estimating the effects of 17α-ethinylestradiol on stochastic population growth rate of fathead minnows: a population synthesis of empirically derived vital rates

Science.gov (United States)

Schwindt, Adam R.; Winkelman, Dana L.

2016-01-01

Urban freshwater streams in arid climates are wastewater effluent dominated ecosystems particularly impacted by bioactive chemicals including steroid estrogens that disrupt vertebrate reproduction. However, more understanding of the population and ecological consequences of exposure to wastewater effluent is needed. We used empirically derived vital rate estimates from a mesocosm study to develop a stochastic stage-structured population model and evaluated the effect of 17α-ethinylestradiol (EE2), the estrogen in human contraceptive pills, on fathead minnow Pimephales promelas stochastic population growth rate. Tested EE2 concentrations ranged from 3.2 to 10.9 ng L−1 and produced stochastic population growth rates (λ S ) below 1 at the lowest concentration, indicating potential for population decline. Declines in λ S compared to controls were evident in treatments that were lethal to adult males despite statistically insignificant effects on egg production and juvenile recruitment. In fact, results indicated that λ S was most sensitive to the survival of juveniles and female egg production. More broadly, our results document that population model results may differ even when empirically derived estimates of vital rates are similar among experimental treatments, and demonstrate how population models integrate and project the effects of stressors throughout the life cycle. Thus, stochastic population models can more effectively evaluate the ecological consequences of experimentally derived vital rates.

Population growth in Shanghai and its characteristics.

Science.gov (United States)

Zhang, K

1985-07-01

There has been an astonishing change in Shanghai's natural population growth over the past 34 years, with a significant difference between urban and suburban areas. In 1954, the birth rate reached as high as 52.6/1000 and the death rate dropped as low as 7.1/1000, the natural growth rate being 45.4/1000. The substantial decline in the rate of natural increase in Shanghai is due to the enormous achievements of family planning programs. In 1983, the 1-child rate of Shanghai areas was 96.56%, with that in urban areas reaching 99.36% and that in rural areas 92.4%. In the last decade, with the development of industrial production, several satellite cities have been built, attracting some of the urban residents from the city proper. The 5 characteristics relating to Shanghai's population growth are: 1) population density is high and population distribution is uneven; 2) fertility declined drastically in the 1970s; 3) the proportion of young is declining and the proportion of aged is increasing; 4) the mortality has been declining steadily, resulting in a longer life expectancy; and 5) the sex ratio has evened out since the liberation when males greatly outnumbered females. These factors point out the arduous task for family planning in the coming years. The enormous population and the increasing number of young people at child bearing ages point out the necessity of carrying on the family planning program.

The uncertainty of future water supply adequacy in megacities: Effects of population growth and climate change

Science.gov (United States)

Alarcon, T.; Garcia, M. E.; Small, D. L.; Portney, K.; Islam, S.

2013-12-01

Providing water to the expanding population of megacities, which have over 10 million people, with a stressed and aging water infrastructure creates unprecedented challenges. These challenges are exacerbated by dwindling supply and competing demands, altered precipitation and runoff patterns in a changing climate, fragmented water utility business models, and changing consumer behavior. While there is an extensive literature on the effects of climate change on water resources, the uncertainty of climate change predictions continues to be high. This hinders the value of these predictions for municipal water supply planning. The ability of water utilities to meet future water needs will largely depend on their capacity to make decisions under uncertainty. Water stressors, like changes in demographics, climate, and socioeconomic patterns, have varying degrees of uncertainty. Identifying which stressors will have a greater impact on water resources, may reduce the level of future uncertainty for planning and managing water utilities. Within this context, we analyze historical and projected changes of population and climate to quantify the relative impacts of these two stressors on water resources. We focus on megacities that rely primarily on surface water resources to evaluate (a) population growth pattern from 1950-2010 and projected population for 2010-2060; (b) climate change impact on projected climate change scenarios for 2010-2060; and (c) water access for 1950-2010; projected needs for 2010-2060.

Suitable Days for Plant Growth Disappear under Projected Climate Change: Potential Human and Biotic Vulnerability.

Directory of Open Access Journals (Sweden)

Camilo Mora

2015-06-01

Full Text Available Ongoing climate change can alter conditions for plant growth, in turn affecting ecological and social systems. While there have been considerable advances in understanding the physical aspects of climate change, comprehensive analyses integrating climate, biological, and social sciences are less common. Here we use climate projections under alternative mitigation scenarios to show how changes in environmental variables that limit plant growth could impact ecosystems and people. We show that although the global mean number of days above freezing will increase by up to 7% by 2100 under "business as usual" (representative concentration pathway [RCP] 8.5, suitable growing days will actually decrease globally by up to 11% when other climatic variables that limit plant growth are considered (i.e., temperature, water availability, and solar radiation. Areas in Russia, China, and Canada are projected to gain suitable plant growing days, but the rest of the world will experience losses. Notably, tropical areas could lose up to 200 suitable plant growing days per year. These changes will impact most of the world's terrestrial ecosystems, potentially triggering climate feedbacks. Human populations will also be affected, with up to ~2,100 million of the poorest people in the world (~30% of the world's population highly vulnerable to changes in the supply of plant-related goods and services. These impacts will be spatially variable, indicating regions where adaptations will be necessary. Changes in suitable plant growing days are projected to be less severe under strong and moderate mitigation scenarios (i.e., RCP 2.6 and RCP 4.5, underscoring the importance of reducing emissions to avoid such disproportionate impacts on ecosystems and people.

Population and the World Bank.

Science.gov (United States)

Sankaran, S

1973-12-01

The World Bank Group regards excessive population growth as the single greatest obstacle to economic and social advance in the underdeveloped world. Since 1969 the Bank and the International Development Agency have provided countries with technical assistance through education, fact-finding, and analysis and given 65.7 million dollars for population projects. These projects, in India, Indonesia, Iran, Jamaica, and Malaysia provide training centers, population education, research, and evaluation as well as actual construction of clinics and mobile units. Because population planning touches sensitive areas of religion, caste, race, morality, and politics, the involved nation's political commitment to plan population growth is critical to the success of any program.

Modeling Population Growth and Extinction

Science.gov (United States)

Gordon, Sheldon P.

2009-01-01

The exponential growth model and the logistic model typically introduced in the mathematics curriculum presume that a population grows exclusively. In reality, species can also die out and more sophisticated models that take the possibility of extinction into account are needed. In this article, two extensions of the logistic model are considered,…

Height-growth response to climatic changes differs among populations of Douglas-fir: A novel analysis of historic data

Science.gov (United States)

Laura P. Leites; Andrew P. Robinson; Gerald E. Rehfeldt; John D. Marshall; Nicholas L. Crookston

2012-01-01

Projected climate change will affect existing forests, as substantial changes are predicted to occur during their life spans. Species that have ample intraspecific genetic differentiation, such as Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco), are expected to display population-specific growth responses to climate change. Using a mixed-effects modeling approach,...

National health expenditure projections: modest annual growth until coverage expands and economic growth accelerates.

Science.gov (United States)

Keehan, Sean P; Cuckler, Gigi A; Sisko, Andrea M; Madison, Andrew J; Smith, Sheila D; Lizonitz, Joseph M; Poisal, John A; Wolfe, Christian J

2012-07-01

For 2011-13, US health spending is projected to grow at 4.0 percent, on average--slightly above the historically low growth rate of 3.8 percent in 2009. Preliminary data suggest that growth in consumers' use of health services remained slow in 2011, and this pattern is expected to continue this year and next. In 2014, health spending growth is expected to accelerate to 7.4 percent as the major coverage expansions from the Affordable Care Act begin. For 2011 through 2021, national health spending is projected to grow at an average rate of 5.7 percent annually, which would be 0.9 percentage point faster than the expected annual increase in the gross domestic product during this period. By 2021, federal, state, and local government health care spending is projected to be nearly 50 percent of national health expenditures, up from 46 percent in 2011, with federal spending accounting for about two-thirds of the total government share. Rising government spending on health care is expected to be driven by faster growth in Medicare enrollment, expanded Medicaid coverage, and the introduction of premium and cost-sharing subsidies for health insurance exchange plans.

Nigerian population growth and its implications for economic development.

Science.gov (United States)

Okpala, A O

1990-12-01

The population of Nigeria is growing at a rate of 3.75%/year indicating a doubling of the population every 22 years. Demographers estimated the population to be 91,178,000 in 1985. Even though population density is high (288 people/square mile), it is not equally distributed. It is highest in the south and southwest urban areas such as Lagos (1045 people/square mile) and lowest in the northeast (75 people/square mile). Moreover rural-urban migration is growing. A major reason for rural-urban migration is the dual nature of the economy in Nigeria. In urban areas, economic development brings about higher standards of living, but, in rural areas, a subsistence economy predominates. This coupled with rapid population growth results in small or no growth in per capita income. Only if the government were to integrate redistribution policies into complete economic development plans should it consider redistributing the population. It should stress rural development (e.g., incentives for firms to set up in rural areas). Further it should move some government offices to rural areas. The government also needs to adopt population policies encouraging the lowering of fertility levels. If it were to provide education through the secondary and prevocational education level free of charge, educated women will lower their fertility. Sex education should be included in the curriculum. Further the government must play an active role in family planning programs, especially educating rural women about family planning. It should also use the mass media to promote small family size, but it should not dictate family size. It also needs to recognize that population growth puts much pressure on the environment. For example, population growth causes soil erosion, nutrient exhaustion, rapid deforestation, and other problems which render the land unusable for agriculture.

Impact of demographic policy on population growth.

Science.gov (United States)

Podyashchikh, P

1968-01-01

Various bourgeois theories, including the reactionary Malthusianism and its variants, challenge the Marxist-Leninist revolutionary theory on the growth of population. Bourgeois science maintains that unchanging biological laws of proliferation form the foundation of social life. Malthus, in his "An Essay on the Principle of Population," contends that population increases in a geometric rate, while means of subsistence tend to increase only in an arithmetic rate: neither the way of production nor social conditions but this law of nature in control of proliferation had been the cause of overpopulation, which again leads to misery, hunger, and unemployment. From this follows the possible conclusion that the working classes should be concerned not about how to change the social order but how to reduce the number of childbirths. Progressive science views the laws of social life in a totally different way. Marxism-Leninism teaches that population size, despite the markedly important role played by it in historical progress, fails to represent that main force of social progress which determines the mode of production and of the distribution of material goods, but just the reverse: the mode of production determines the growth of population, the changes in its density and composition. Marxism-Leninism teaches that each historical stage of production (slavery, feudalism, capitalism) has its own special, historically valid demographic law. Bourgeois science maintains that humankind faces an absolute overpopulation caused by the means of production lagging behind the growth of population. Actually this is only a relative overpopulation due to the fact that capitalistic production is subjected to the interests of increasing capitalistic profit and not to those of meeting the demands of population. In socialist countries, production is incessantly developing and expanding, and employment of the entire productive population is ensured. Consequently, the problem of relative

On the theory of global population growth

International Nuclear Information System (INIS)

Kapitza, Sergei P

2010-01-01

Ours is an epoch of global demographic revolution, a time of a rapid transition from explosive population growth to a low reproduction level. This, possibly the most momentous change ever witnessed by humankind has, first and foremost, important implications for the dynamics of population. But it also affects billions of people in all aspects of their lives, and it is for this reason that demographic processes have grown into a vast problem, both globally and in Russia. Their fundamental understanding will to a large extent impact the present, the short-term future following the current critical epoch, the stable and uniform global development and its priorities, and indeed global security. Quantitative treatment of historical processes is reached using the phenomenological theory of mankind's population growth. This theory relies on the concepts and methods of physics and its conclusions should take into account the ideas of economics and genetics. (interdisciplinary physics)

The Female Population Growth Projection Year 2021 in Trenggalek Regency by Leslie Matrix Model on the Birth Rate and Life Expectancy

Directory of Open Access Journals (Sweden)

Dewi Anggreini

2017-10-01

Full Text Available This research aims to determine the number of female residents in Trenggalek Regency in 2021 based on data on birth rate and life expectancy. The use of eigenvalues and eigenvectors aims to determine the dividing age distribution by Leslie matrix model. The eigenvectors are used to determine the number of female populations of each age interval, while the eigenvalues are used to determine population growth rates. The research method used is to determine the subject of research. The next stage is to collect research data, then analyze the data and last draw conclusions. The research data is obtained from BPS Kabupaten Trenggalek and BPS East Java Province that is data of woman population from year 2010-2015. The result of this research using Leslie matrix model for female population in Trenggalek Regency that is discrete model. The discrete model is divided into fourteen age intervals constructed using the birthrate and life expectancy. The conclusions of the study showed that the number of female population in Trenggalek Regency tended to increase with positive eigen value greater than one. In other words, the growth rate of female population in Trenggalek Regency tends to be positive. The success of Leslie's matrix model is the application of case studies in predicting the number of female populations in Trenggalek District by 2021 using the MAPLE 16 Program.

Population growth and economic development: two new U.S. perspectives.

Science.gov (United States)

Wulf, D; Klitsch, M

1986-01-01

This report compares the research paths of economic development reports by the US National Academy of Sciences (NAS) and the American Assembly of Columbia University. The NAS group, made up principally of economists and demographers, refrained from recommending population reduction targets, in contrast to the stronger terms of its 1971 report. A 1965 report by the Assembly spoke of population as a serious negative influence for economic development, political stability, and world peace, while the new report speaks of negative socioeconomic effects, and of the limiting of a person's right to control family size. The NAS agenda was established before the US delegation to the UN population conference in Mexico City retreated from declaring population growth to be a necessarily negative influencer of socioeconomic progress. The Assembly took the position that possible benefits of population growth would be far outweighed by factors such as resource depletion and women's health. The NAS maintained that growth might provide incentives for institutional adjustments (market development, investment in education) and control of growth should not be considered a substitute for such interventions. Both reports agree that control of fertility is a human right, but the NAS report examined the question of the acceptable degree of compulsion to be used to encourage couples. The Assembly objected to limiting access to family planning by defunding abortion programs oversease. Differences exist between the 2 reports in questins such as the negative impact of 1950's population growth, the synergistic effect of growth on many areas of human activity, the extent to which welfare of future generations is considered relevant today, and the adequacy of pure economic analysis in assessing need. Much study of population/development linkages is still required.

Population Growth in the 1990s: Patterns within the United States.

Science.gov (United States)

Perry, Marc

2002-01-01

Examines population growth during the 1990s for a variety of geographic levels including regions, divisions, states, metropolitan areas, counties, and large cities. Compares growth rates for the 1990s with earlier decades to provide an historical context for present-day trends in population growth and decline. Discusses how differential population…

Future coastal population growth and exposure to sea-level rise and coastal flooding--a global assessment.

Directory of Open Access Journals (Sweden)

Barbara Neumann

Full Text Available Coastal zones are exposed to a range of coastal hazards including sea-level rise with its related effects. At the same time, they are more densely populated than the hinterland and exhibit higher rates of population growth and urbanisation. As this trend is expected to continue into the future, we investigate how coastal populations will be affected by such impacts at global and regional scales by the years 2030 and 2060. Starting from baseline population estimates for the year 2000, we assess future population change in the low-elevation coastal zone and trends in exposure to 100-year coastal floods based on four different sea-level and socio-economic scenarios. Our method accounts for differential growth of coastal areas against the land-locked hinterland and for trends of urbanisation and expansive urban growth, as currently observed, but does not explicitly consider possible displacement or out-migration due to factors such as sea-level rise. We combine spatially explicit estimates of the baseline population with demographic data in order to derive scenario-driven projections of coastal population development. Our scenarios show that the number of people living in the low-elevation coastal zone, as well as the number of people exposed to flooding from 1-in-100 year storm surge events, is highest in Asia. China, India, Bangladesh, Indonesia and Viet Nam are estimated to have the highest total coastal population exposure in the baseline year and this ranking is expected to remain largely unchanged in the future. However, Africa is expected to experience the highest rates of population growth and urbanisation in the coastal zone, particularly in Egypt and sub-Saharan countries in Western and Eastern Africa. The results highlight countries and regions with a high degree of exposure to coastal flooding and help identifying regions where policies and adaptive planning for building resilient coastal communities are not only desirable but essential

Future coastal population growth and exposure to sea-level rise and coastal flooding--a global assessment.

Science.gov (United States)

Neumann, Barbara; Vafeidis, Athanasios T; Zimmermann, Juliane; Nicholls, Robert J

2015-01-01

Coastal zones are exposed to a range of coastal hazards including sea-level rise with its related effects. At the same time, they are more densely populated than the hinterland and exhibit higher rates of population growth and urbanisation. As this trend is expected to continue into the future, we investigate how coastal populations will be affected by such impacts at global and regional scales by the years 2030 and 2060. Starting from baseline population estimates for the year 2000, we assess future population change in the low-elevation coastal zone and trends in exposure to 100-year coastal floods based on four different sea-level and socio-economic scenarios. Our method accounts for differential growth of coastal areas against the land-locked hinterland and for trends of urbanisation and expansive urban growth, as currently observed, but does not explicitly consider possible displacement or out-migration due to factors such as sea-level rise. We combine spatially explicit estimates of the baseline population with demographic data in order to derive scenario-driven projections of coastal population development. Our scenarios show that the number of people living in the low-elevation coastal zone, as well as the number of people exposed to flooding from 1-in-100 year storm surge events, is highest in Asia. China, India, Bangladesh, Indonesia and Viet Nam are estimated to have the highest total coastal population exposure in the baseline year and this ranking is expected to remain largely unchanged in the future. However, Africa is expected to experience the highest rates of population growth and urbanisation in the coastal zone, particularly in Egypt and sub-Saharan countries in Western and Eastern Africa. The results highlight countries and regions with a high degree of exposure to coastal flooding and help identifying regions where policies and adaptive planning for building resilient coastal communities are not only desirable but essential. Furthermore, we

Future Coastal Population Growth and Exposure to Sea-Level Rise and Coastal Flooding - A Global Assessment

Science.gov (United States)

Neumann, Barbara; Vafeidis, Athanasios T.; Zimmermann, Juliane; Nicholls, Robert J.

2015-01-01

Coastal zones are exposed to a range of coastal hazards including sea-level rise with its related effects. At the same time, they are more densely populated than the hinterland and exhibit higher rates of population growth and urbanisation. As this trend is expected to continue into the future, we investigate how coastal populations will be affected by such impacts at global and regional scales by the years 2030 and 2060. Starting from baseline population estimates for the year 2000, we assess future population change in the low-elevation coastal zone and trends in exposure to 100-year coastal floods based on four different sea-level and socio-economic scenarios. Our method accounts for differential growth of coastal areas against the land-locked hinterland and for trends of urbanisation and expansive urban growth, as currently observed, but does not explicitly consider possible displacement or out-migration due to factors such as sea-level rise. We combine spatially explicit estimates of the baseline population with demographic data in order to derive scenario-driven projections of coastal population development. Our scenarios show that the number of people living in the low-elevation coastal zone, as well as the number of people exposed to flooding from 1-in-100 year storm surge events, is highest in Asia. China, India, Bangladesh, Indonesia and Viet Nam are estimated to have the highest total coastal population exposure in the baseline year and this ranking is expected to remain largely unchanged in the future. However, Africa is expected to experience the highest rates of population growth and urbanisation in the coastal zone, particularly in Egypt and sub-Saharan countries in Western and Eastern Africa. The results highlight countries and regions with a high degree of exposure to coastal flooding and help identifying regions where policies and adaptive planning for building resilient coastal communities are not only desirable but essential. Furthermore, we

Optimal growth entails risky localization in population dynamics

Science.gov (United States)

Gueudré, Thomas; Martin, David G.

2018-03-01

Essential to each other, growth and exploration are jointly observed in alive and inanimate entities, such as animals, cells or goods. But how the environment's structural and temporal properties weights in this balance remains elusive. We analyze a model of stochastic growth with time correlations and diffusive dynamics that sheds light on the way populations grow and spread over general networks. This model suggests natural explanations of empirical facts in econo-physics or ecology, such as the risk-return trade-off and the Zipf law. We conclude that optimal growth leads to a localized population distribution, but such risky position can be mitigated through the space geometry. These results have broad applicability and are subsequently illustrated over an empirical study of financial data.

Growing pains: How risk perception and risk communication research can help to manage the challenges of global population growth.

Science.gov (United States)

Dawson, Ian G J; Johnson, Johnnie E V

2014-08-01

In 2011, the global human population reached 7 billion and medium variant projections indicate that it will exceed 9 billion before 2045. Theoretical and empirical perspectives suggest that this growth could lead to an increase in the likelihood of adverse events (e.g., food shortages, climate change, etc.) and/or the severity of adverse events (e.g., famines, natural disasters, etc.). Several scholars have posited that the size to which the global population grows and the extent to which this growth increases the likelihood of adverse outcomes will largely be shaped by individuals' decisions (in households, organizations, governments, etc.). In light of the strong relationship between perceived risk and decision behaviors, it is surprising that there remains a dearth of empirical research that specifically examines the perceived risks of population growth and how these perceptions might influence related decisions. In an attempt to motivate this important strand of research, this article examines the major risks that may be exacerbated by global population growth and draws upon empirical work concerning the perception and communication of risk to identify potential directions for future research. The article also considers how individuals might perceive both the risks and benefits of population growth and be helped to better understand and address the related issues. The answers to these questions could help humanity better manage the emerging consequences of its continuing success in increasing infant survival and adult longevity. © 2014 Society for Risk Analysis.

NIDI scenario. Strong population decline in China

NARCIS (Netherlands)

de Beer, J.A.A.

2016-01-01

United Nations projections assume that by the end of this century one third of the world population will live in India, China or Nigeria. While population growth in India will slow down and the population size of China will decline, population growth in Nigeria will accelerate. A new NIDI scenario

Geographic distribution of habitat, development, and population growth rates of the Asian citrus psyllid, Diaphorina citri, in Mexico.

Science.gov (United States)

López-Collado, José; Isabel López-Arroyo, J; Robles-García, Pedro L; Márquez-Santos, Magdalena

2013-01-01

The Asian citrus psyllid, Diaphorina citri Kuwayama (Hemiptera: Psyllidae), is an introduced pest in Mexico and a vector of huanglongbing, a lethal citrus disease. Estimations of the habitat distribution and population growth rates of D. citri are required to establish regional and areawide management strategies and can be used as a pest risk analysis tools. In this study, the habitat distribution of D. citri in Mexico was computed with MaxEnt, an inductive, machine-learning program that uses bioclimatic layers and point location data. Geographic distributions of development and population growth rates were determined by fitting a temperature-dependent, nonlinear model and projecting the rates over the target area, using the annual mean temperature as the predictor variable. The results showed that the most suitable regions for habitat of D. citri comprise the Gulf of Mexico states, Yucatán Peninsula, and areas scattered throughout the Pacific coastal states. Less suitable areas occurred in northern and central states. The most important predictor variables were related to temperature. Development and growth rates had a distribution wider than habitat, reaching some of the northern states of México. Habitat, development, and population growth rates were correlated to each other and with the citrus producing area. These relationships indicated that citrus producing states are within the most suitable regions for the occurrence, development, and population growth of D. citri, therefore increasing the risk of huanglongbing dispersion.

[Population: evolution of Rwandan attitudes or the adaptation of the Rwanda population to population growth].

Science.gov (United States)

Ngendakumana, M

1988-04-01

A consequence of the increasing pressure on Rwanda's ecosystem resulting from population growth has been that demographic factors have played a significant role in modifying attitudes and beliefs of the population. The history of Rwanda demonstrates a constant struggle for survival in the face of increasing population pressure. Migration, colonization of new agricultural lands, adoption of new crops and new forms of animal husbandry have been responses to population pressures. Recent unprecedented population growth has exceeded the capacity of older systems of cultivation and combinations of agricultural and animal husbandry to support the population. Smaller animals have largely replaced the cattle that once roamed freely in extensive pastures, and new techniques of stabling animals, use of organic or chemical fertilizers, and new tools adapted to the shrinking size of farm plots have represented responses to the new demographic realities. The concept of the family is likewise undergoing modification in the face of population growth and modernization. Children, who once were valued as a source of labor and constrained to conform to the wishes of the parents in return for the eventual inheritance of the goods and livelihood, now increasingly look beyond the household for education and employment. Family land holdings have become too small to support all the members with a claim on them. The greater distances between family members inevitably mean that relations between them lose closeness. The choice of a marriage partner is increasingly assumed by the young people themselves and not by their families. Old traditions of food sharing and hospitality have been curtailed because of the increasing scarcity of food. Despite the changes engendered by increasing population pressure, pronatalist sentiments are still widespread. But the desire to assure the future of each child rather than to await his services, a new conception of women less dependent on their reproductive

Taking Exception. Reduced mortality leads to population growth: an inconvenient truth.

Science.gov (United States)

Shelton, James D

2014-05-01

Reduced mortality has been the predominant cause of the marked global population growth over the last 3/4 of a century. While improved child survival increases motivation to reduce fertility, it comes too little and too late to forestall substantial population growth. And, beyond motivation, couples need effective means to control their fertility. It is an inconvenient truth that reducing child mortality contributes considerably to the population growth destined to compromise the quality of life of many, particularly in sub-Saharan Africa. Vigorous child survival programming is of course imperative. Wide access to voluntary family planning can help mitigate that growth and provide many other benefits.

Population growth and economic development.

Science.gov (United States)

Corbridge, S

1989-01-01

The Malthusian and neo-Malthusian approaches to the role of population growth in economic development and resource depletion are briefly outlined. Three arguments are then presented that emphasize demographic determinism, empirical evidence, and cause and effect. The author concludes that non-coercive family planning programs may have a role to play in countries that are unable to reduce inequalities, particularly for the poor and for women.

Projecting long term medical spending growth.

Science.gov (United States)

Borger, Christine; Rutherford, Thomas F; Won, Gregory Y

2008-01-01

We present a dynamic general equilibrium model of the U.S. economy and the medical sector in which the adoption of new medical treatments is endogenous and the demand for medical services is conditional on the state of technology. We use this model to prepare 75-year medical spending forecasts and a projection of the Medicare actuarial balance, and we compare our results to those obtained from a method that has been used by government actuaries. Our baseline forecast predicts slower health spending growth in the long run and a lower Medicare actuarial deficit relative to the previous projection methodology.

Experimental design and estimation of growth rate distributions in size-structured shrimp populations

International Nuclear Information System (INIS)

Banks, H T; Davis, Jimena L; Ernstberger, Stacey L; Hu, Shuhua; Artimovich, Elena; Dhar, Arun K

2009-01-01

We discuss inverse problem results for problems involving the estimation of probability distributions using aggregate data for growth in populations. We begin with a mathematical model describing variability in the early growth process of size-structured shrimp populations and discuss a computational methodology for the design of experiments to validate the model and estimate the growth-rate distributions in shrimp populations. Parameter-estimation findings using experimental data from experiments so designed for shrimp populations cultivated at Advanced BioNutrition Corporation are presented, illustrating the usefulness of mathematical and statistical modeling in understanding the uncertainty in the growth dynamics of such populations

Drought tolerance and growth in populations of a wide-ranging tree species indicate climate change risks for the boreal north.

Science.gov (United States)

Montwé, David; Isaac-Renton, Miriam; Hamann, Andreas; Spiecker, Heinrich

2016-02-01

Choosing drought-tolerant planting stock in reforestation programs may help adapt forests to climate change. To inform such reforestation strategies, we test lodgepole pine (Pinus contorta Doug. ex Loud. var latifolia Englm.) population response to drought and infer potential benefits of a northward transfer of seeds from drier, southern environments. The objective is addressed by combining dendroecological growth analysis with long-term genetic field trials. Over 500 trees originating from 23 populations across western North America were destructively sampled in three experimental sites in southern British Columbia, representing a climate warming scenario. Growth after 32 years from provenances transferred southward or northward over long distances was significantly lower than growth of local populations. All populations were affected by a severe natural drought event in 2002. The provenances from the most southern locations showed the highest drought tolerance but low productivity. Local provenances were productive and drought tolerant. Provenances from the boreal north showed lower productivity and less drought tolerance on southern test sites than all other sources, implying that maladaptation to drought may prevent boreal populations from taking full advantage of more favorable growing conditions under projected climate change. © 2015 John Wiley & Sons Ltd.

Assessing the Impact of Population Growth, Climate Change, and Land Use Change on Water Resources in India

Science.gov (United States)

Singh, N.; Cherkauer, K. A.

2014-12-01

India is poised to become the most populous country in the world by 2019 and reach a population of over 2 billion by 2050 based on current growth rates. It is also a region which will be under severe socio-economic and environmental stress if mitigation efforts are not adapted. In the past 10 years the population of India has grown by an average rate of 17 million people per year. In addition to unprecedented population growth, rapid urbanization and industrialization are straining the overburdened environmental system. This rapid growth in population, urbanization and industrialized will result in increased demand for food, requiring expansion of agricultural resources. Since total agricultural land in India has been relatively constant over the past 10 years the demand for additional food has to be partly met by enhanced production on existing land. Arable land in India has declined by around 3% according to FAOSTAT while the total agricultural area under irrigation has increased by about 9% thus further straining its water resources. In addition projections for future climate indicate that India is one of the regions where water resources are expected to be negatively impacted. Total agriculture water withdrawal in India increased by approximately 18 % from 2000-2010 while the total per capita water withdrawal increased by over 9% from 2000-2010. Total freshwater withdrawal as percentage of renewable water resources was around 40% in 2010. In addition, recent mandates of biofuel policies in India are also expected to impact its water resources. The combined impact of these various factors on future water availability in India could be one of the most severe globally due its unprecedented increase in population, food production and industrialization. In this study we assess the impact of land use and climate change on water resources over southern India in the face of a growing population and interest in development of national biofuel supplies. We use

Impact of Population Aging on Asia's Future Growth

OpenAIRE

Park, Donghyun; Shin, Kwanho

2011-01-01

First, the expert contributors argue, Asia must find ways to sustain rapid economic growth in the face of less favorable demographics, which implies slower growth of the workforce. Second, they contend, Asia must find ways to deliver affordable, adequate, and sustainable old-age economic security for its growing elderly population. Underpinned by rigorous analysis, a wide range of concrete policy options for sustaining economic growth while delivering economic security for the elderly are the...

Coastal seas as resource for Blue Growth - SmartSea project

Science.gov (United States)

Kotilainen, Aarno; Alvi, Kimmo; Boman, Anton; Hämäläinen, Jyrki; Kaskela, Anu; Rantataro, Jyrki; Vallius, Henry; Virtasalo, Joonas

2017-04-01

Blue growth is a long term strategy of the European Union (EU) to enhance the sustainable growth of the maritime sector. Our surrounding seas have been drivers for the European economy for a long time, but still they have great potential for further exploiting of natural resources and economic growth. Especially if the growth can be achieved in an environmentally sustainable way, benefits are obvious. It has been estimated that improvement of the state of the Baltic Sea would until 2030 create 900 000 jobs in the whole Baltic Sea area, mainly in Blue Tech, tourism, real estate and building businesses (Dahlgren et al. 2015). However, coastal seas already experience multiple stressors like off-shore construction, pollution, eutrophication, shipping, over-fishing, and climate change. In order to obtain sustainable Blue Growth, it is necessary to localize and assess the current maritime activities, estimate their growth potential, and investigate their present and future effects on each other and on the marine environment. The purpose of the SmartSea project is to support the growth of commercial marine activities in the Gulf of Bothnia region, in the northern Baltic Sea. The Gulf of Bothnia is an essential resource in terms of fish farming and wind power, for example, and it is also possible to make use of the geological resources of the gulf. Moreover, the rapid growth of the commercial marine activities and the consequences of the climate change may lead to conflicts between the different activities and harm the marine ecosystem of the Gulf of Bothnia. The SmartSea project aims to identify these risks and find solutions for the sustainable use of the sea. SmartSea project is funded by the Strategic Research Council of Academy of Finland, grant No: 292 985. The project will last for six years (2015-2020) and its funding totals nearly 8 million euros. The project involves close to 40 researchers from eight different institutions: the Finnish Meteorological Institute

Urban and rural population growth in a spatial panel of municipalities

NARCIS (Netherlands)

Costa da Silva, Diego Firmino; Elhorst, J. Paul; Silveira Neto, Raul da Mota

2017-01-01

Urban and rural population growth in a spatial panel of municipalities. Regional Studies. Using Bayesian posterior model probabilities and data pertaining to 3659 Brazilian minimum comparable areas (MCAs) over the period 1970-2010, two theoretical settings of population growth dynamics resulting in

Stochastic dynamics and logistic population growth

Science.gov (United States)

Méndez, Vicenç; Assaf, Michael; Campos, Daniel; Horsthemke, Werner

2015-06-01

The Verhulst model is probably the best known macroscopic rate equation in population ecology. It depends on two parameters, the intrinsic growth rate and the carrying capacity. These parameters can be estimated for different populations and are related to the reproductive fitness and the competition for limited resources, respectively. We investigate analytically and numerically the simplest possible microscopic scenarios that give rise to the logistic equation in the deterministic mean-field limit. We provide a definition of the two parameters of the Verhulst equation in terms of microscopic parameters. In addition, we derive the conditions for extinction or persistence of the population by employing either the momentum-space spectral theory or the real-space Wentzel-Kramers-Brillouin approximation to determine the probability distribution function and the mean time to extinction of the population. Our analytical results agree well with numerical simulations.

Endogenous population growth may imply chaos.

Science.gov (United States)

Prskawetz, A; Feichtinger, G

1995-01-01

The authors consider a discrete-time neoclassical growth model with an endogenous rate of population growth. The resulting one-dimensional map for the capital intensity has a tilted z-shape. Using the theory of nonlinear dynamical systems, they obtain numerical results on the qualitative behavior of time paths for changing parameter values. Besides stable and periodic solutions, erratic time paths may result. In particular, myopic and far-sighted economies--assumed to be characterized by low and high savings rate respectively--are characterized by stable per capita capital stocks, while solutions with chaotic windows exist between these two extremes.

Population facts that can spur women's well being.

Science.gov (United States)

Harrison, P

1994-01-01

Although women's rights proposals included in the International Conference on Population and Development deserve support on their own merit, governments are more likely to increase funding for human development if the environmental and economic advantages of investing in women are spelled out. A significant negative association between income growth and population growth emerged in the 1980s. During this decade, 41 countries where population was growing more slowly demonstrated an average income growth of 1.23% per year, while average income fell by an average of 1.25% per year in 41 countries where there was more rapid population growth. In the 1965-80 period, there was no such correlation. Moreover, population control is among the most effective measures for protecting the environment. If--through female education, women's rights, maternal-child health, and family planning--the United Nations' low population projection existed in the year 2050 as opposed to the medium projection (2.2 billion higher), 4.4 million square kilometers of land would be saved and there would be 9.3 billion tones less in carbon dioxide emissions per year. This would be equivalent to halting all current deforestation and a 26% improvement in global energy improvement. Achievement of the low projection would further result in 342 million fewer cases of malnutrition than the medium projection.

A new population growth map with variable coefficients

International Nuclear Information System (INIS)

Jannussis, A.

1986-01-01

In the present paper it is investigated a simple population growth map with variable coefficients. Moreover, it is studied the new population map of the form xsub(j+1) = axsub(j) (1/(1 + bxsub(j)) -1/(1 + cxsub(j))), c not= b, j = 0, 1,..., which is transformed in an equivalent logistic map

Modeling geo-homopholy in online social networks for population distribution projection

Directory of Open Access Journals (Sweden)

Yuanxing Zhang

2017-09-01

Full Text Available Purpose – Projecting the population distribution in geographical regions is important for many applications such as launching marketing campaigns or enhancing the public safety in certain densely populated areas. Conventional studies require the collection of people’s trajectory data through offline means, which is limited in terms of cost and data availability. The wide use of online social network (OSN apps over smartphones has provided the opportunities of devising a lightweight approach of conducting the study using the online data of smartphone apps. This paper aims to reveal the relationship between the online social networks and the offline communities, as well as to project the population distribution by modeling geo-homophily in the online social networks. Design/methodology/approach – In this paper, the authors propose the concept of geo-homophily in OSNs to determine how much the data of an OSN can help project the population distribution in a given division of geographical regions. Specifically, the authors establish a three-layered theoretic framework that first maps the online message diffusion among friends in the OSN to the offline population distribution over a given division of regions via a Dirichlet process and then projects the floating population across the regions. Findings – By experiments over large-scale OSN data sets, the authors show that the proposed prediction models have a high prediction accuracy in characterizing the process of how the population distribution forms and how the floating population changes over time. Originality/value – This paper tries to project population distribution by modeling geo-homophily in OSNs.

Feeding the world's increasing population while limiting climate change impacts: linking N2O and CH4 emissions from agriculture to population growth

International Nuclear Information System (INIS)

Beek, Christy L. van; Meerburg, Bastiaan G.; Schils, Rene L.M.; Verhagen, Jan; Kuikman, Peter J.

2010-01-01

The global demand for agricultural products, including food, is rapidly increasing due to population growth and shifts in consumption patterns. The required increase in agricultural production is predominantly to be achieved in countries with relatively low agricultural production levels at present. These are mainly developing countries and countries in transition, the so-called non-Annex I countries of the UNFCCC. However, intensification of agricultural production systems is currently closely linked to high emissions of greenhouse gases notably nitrous oxide (N 2 O) and methane (CH 4 ). In this paper the relations between population growth, agricultural development and emissions of N 2 O and CH 4 were assessed for 10 non-Annex I countries, viz. China, India, Vietnam, Brazil, Argentina, Mexico, Mongolia, Nigeria, Tanzania and South Africa. We combined FAO data on agricultural production levels, CENSUS data on population statistics and EDGAR data on N 2 O and CH 4 emissions. The projected trends in agricultural production indicate that emissions of N 2 O and CH 4 are expected to increase rapidly in the coming years and will level off from 2040 onwards. The results confirm the positive relation between population increase and increased emissions from agricultural activities for most countries. However, for some countries (South Africa, China and Mexico) this relation was weak or absent. Although numerous factors (e.g. changes in international trade) may have scattered the relation and we were unable to explain this decoupling, it suggests that population growth can be possible without additional emissions. The variation between the different countries and farming systems is however large and mitigation measures at farm-level should be tailored to the wide diversity in environmental conditions, regional customs and farming systems.

The utility of estimating population-level trajectories of terminal wellbeing decline within a growth mixture modelling framework.

Science.gov (United States)

Burns, R A; Byles, J; Magliano, D J; Mitchell, P; Anstey, K J

2015-03-01

Mortality-related decline has been identified across multiple domains of human functioning, including mental health and wellbeing. The current study utilised a growth mixture modelling framework to establish whether a single population-level trajectory best describes mortality-related changes in both wellbeing and mental health, or whether subpopulations report quite different mortality-related changes. Participants were older-aged (M = 69.59 years; SD = 8.08 years) deceased females (N = 1,862) from the dynamic analyses to optimise ageing (DYNOPTA) project. Growth mixture models analysed participants' responses on measures of mental health and wellbeing for up to 16 years from death. Multi-level models confirmed overall terminal decline and terminal drop in both mental health and wellbeing. However, modelling data from the same participants within a latent class growth mixture framework indicated that most participants reported stability in mental health (90.3 %) and wellbeing (89.0 %) in the years preceding death. Whilst confirming other population-level analyses which support terminal decline and drop hypotheses in both mental health and wellbeing, we subsequently identified that most of this effect is driven by a small, but significant minority of the population. Instead, most individuals report stable levels of mental health and wellbeing in the years preceding death.

Life-history and spatial determinants of somatic growth dynamics in Komodo dragon populations.

Science.gov (United States)

Laver, Rebecca J; Purwandana, Deni; Ariefiandy, Achmad; Imansyah, Jeri; Forsyth, David; Ciofi, Claudio; Jessop, Tim S

2012-01-01

Somatic growth patterns represent a major component of organismal fitness and may vary among sexes and populations due to genetic and environmental processes leading to profound differences in life-history and demography. This study considered the ontogenic, sex-specific and spatial dynamics of somatic growth patterns in ten populations of the world's largest lizard the Komodo dragon (Varanus komodoensis). The growth of 400 individual Komodo dragons was measured in a capture-mark-recapture study at ten sites on four islands in eastern Indonesia, from 2002 to 2010. Generalized Additive Mixed Models (GAMMs) and information-theoretic methods were used to examine how growth rates varied with size, age and sex, and across and within islands in relation to site-specific prey availability, lizard population density and inbreeding coefficients. Growth trajectories differed significantly with size and between sexes, indicating different energy allocation tactics and overall costs associated with reproduction. This leads to disparities in maximum body sizes and longevity. Spatial variation in growth was strongly supported by a curvilinear density-dependent growth model with highest growth rates occurring at intermediate population densities. Sex-specific trade-offs in growth underpin key differences in Komodo dragon life-history including evidence for high costs of reproduction in females. Further, inverse density-dependent growth may have profound effects on individual and population level processes that influence the demography of this species.

Life-history and spatial determinants of somatic growth dynamics in Komodo dragon populations.

Directory of Open Access Journals (Sweden)

Rebecca J Laver

Full Text Available Somatic growth patterns represent a major component of organismal fitness and may vary among sexes and populations due to genetic and environmental processes leading to profound differences in life-history and demography. This study considered the ontogenic, sex-specific and spatial dynamics of somatic growth patterns in ten populations of the world's largest lizard the Komodo dragon (Varanus komodoensis. The growth of 400 individual Komodo dragons was measured in a capture-mark-recapture study at ten sites on four islands in eastern Indonesia, from 2002 to 2010. Generalized Additive Mixed Models (GAMMs and information-theoretic methods were used to examine how growth rates varied with size, age and sex, and across and within islands in relation to site-specific prey availability, lizard population density and inbreeding coefficients. Growth trajectories differed significantly with size and between sexes, indicating different energy allocation tactics and overall costs associated with reproduction. This leads to disparities in maximum body sizes and longevity. Spatial variation in growth was strongly supported by a curvilinear density-dependent growth model with highest growth rates occurring at intermediate population densities. Sex-specific trade-offs in growth underpin key differences in Komodo dragon life-history including evidence for high costs of reproduction in females. Further, inverse density-dependent growth may have profound effects on individual and population level processes that influence the demography of this species.

Life-History and Spatial Determinants of Somatic Growth Dynamics in Komodo Dragon Populations

Science.gov (United States)

Laver, Rebecca J.; Purwandana, Deni; Ariefiandy, Achmad; Imansyah, Jeri; Forsyth, David; Ciofi, Claudio; Jessop, Tim S.

2012-01-01

Somatic growth patterns represent a major component of organismal fitness and may vary among sexes and populations due to genetic and environmental processes leading to profound differences in life-history and demography. This study considered the ontogenic, sex-specific and spatial dynamics of somatic growth patterns in ten populations of the world’s largest lizard the Komodo dragon (Varanus komodoensis). The growth of 400 individual Komodo dragons was measured in a capture-mark-recapture study at ten sites on four islands in eastern Indonesia, from 2002 to 2010. Generalized Additive Mixed Models (GAMMs) and information-theoretic methods were used to examine how growth rates varied with size, age and sex, and across and within islands in relation to site-specific prey availability, lizard population density and inbreeding coefficients. Growth trajectories differed significantly with size and between sexes, indicating different energy allocation tactics and overall costs associated with reproduction. This leads to disparities in maximum body sizes and longevity. Spatial variation in growth was strongly supported by a curvilinear density-dependent growth model with highest growth rates occurring at intermediate population densities. Sex-specific trade-offs in growth underpin key differences in Komodo dragon life-history including evidence for high costs of reproduction in females. Further, inverse density-dependent growth may have profound effects on individual and population level processes that influence the demography of this species. PMID:23028983

Spatial variability and macro‐scale drivers of growth for native and introduced Flathead Catfish populations

Science.gov (United States)

Massie, Danielle L.; Smith, Geoffrey; Bonvechio, Timothy F.; Bunch, Aaron J.; Lucchesi, David O.; Wagner, Tyler

2018-01-01

Quantifying spatial variability in fish growth and identifying large‐scale drivers of growth are fundamental to many conservation and management decisions. Although fish growth studies often focus on a single population, it is becoming increasingly clear that large‐scale studies are likely needed for addressing transboundary management needs. This is particularly true for species with high recreational value and for those with negative ecological consequences when introduced outside of their native range, such as the Flathead Catfish Pylodictis olivaris. This study quantified growth variability of the Flathead Catfish across a large portion of its contemporary range to determine whether growth differences existed between habitat types (i.e., reservoirs and rivers) and between native and introduced populations. Additionally, we investigated whether growth parameters varied as a function of latitude and time since introduction (for introduced populations). Length‐at‐age data from 26 populations across 11 states in the USA were modeled using a Bayesian hierarchical von Bertalanffy growth model. Population‐specific growth trajectories revealed large variation in Flathead Catfish growth and relatively high uncertainty in growth parameters for some populations. Relatively high uncertainty was also evident when comparing populations and when quantifying large‐scale patterns. Growth parameters (Brody growth coefficient [K] and theoretical maximum average length [L∞]) were not different (based on overlapping 90% credible intervals) between habitat types or between native and introduced populations. For populations within the introduced range of Flathead Catfish, latitude was negatively correlated with K. For native populations, we estimated an 85% probability that L∞ estimates were negatively correlated with latitude. Contrary to predictions, time since introduction was not correlated with growth parameters in introduced populations of Flathead Catfish

Life history, population viability, and the potential for local adaptation in isolated trout populations

Directory of Open Access Journals (Sweden)

K.J. Carim

2017-04-01

Full Text Available Habitat loss and fragmentation have caused population decline across taxa through impacts on life history diversity, dispersal patterns, and gene flow. Yet, intentional isolation of native fish populations is a frequently used management strategy to protect against negative interactions with invasive fish species. We evaluated the population viability and genetic diversity of 12 isolated populations of Oncorhynchus clarkii lewisi located on the Flathead Indian Reservation in Montana, USA. Length-structured integral projection models (IPMs were used to project population growth rate (lambda and its sensitivity to underlying vital rates and parameters. We examined relationships between lambda, genetic diversity, and habitat size and quality. Lambda ranged from 0.68 to 1.1 with 10 of 12 populations projected to be in decline. A sensitivity analysis of lambda with respect to projection matrix elements indicated that lambda was generally sensitive to changes in early life history stages (survival/growth, but patterns differed among populations. Another sensitivity analysis with respect to underlying model parameters showed highly consistent pattern across populations, with lambda being most sensitive to the slope of probability of maturity (estimated from published literature, generally followed by adult survival, and the slope of somatic growth rate (directly measured from each population. Lambda was not correlated with genetic diversity. For populations residing in small isolated streams (≤5 km of occupied habitat, lambda significantly increased with base flow discharge (r2=0.50, p<0.02. Our results highlight the potential importance of local adaptation for persistence of small, isolated populations. Specifically we saw evidence for higher probability of maturity at smaller sizes in the smallest, coldest isolated systems, increasing probability of persistence for these populations. Climate change threatens to further fragment populations of

The between-population genetic architecture of growth, maturation, and plasticity in Atlantic salmon.

Science.gov (United States)

Debes, Paul Vincent; Fraser, Dylan John; Yates, Matthew; Hutchings, Jeffrey A

2014-04-01

The between-population genetic architecture for growth and maturation has not been examined in detail for many animal species despite its central importance in understanding hybrid fitness. We studied the genetic architecture of population divergence in: (i) maturation probabilities at the same age; (ii) size at age and growth, while accounting for maturity status and sex; and (iii) growth plasticity in response to environmental factors, using divergent wild and domesticated Atlantic salmon (Salmo salar). Our work examined two populations and their multigenerational hybrids in a common experimental arrangement in which salinity and quantity of suspended sediments were manipulated to mimic naturally occurring environmental variation. Average specific growth rates across environments differed among crosses, maturity groups, and cross-by-maturity groups, but a growth-rate reduction in the presence of suspended sediments was equal for all groups. Our results revealed both additive and nonadditive outbreeding effects for size at age and for growth rates that differed with life stage, as well as the presence of different sex- and size-specific maturation probabilities between populations. The major implication of our work is that estimates of the genetic architecture of growth and maturation can be biased if one does not simultaneously account for temporal changes in growth and for different maturation probabilities between populations. Namely, these correlated traits interact differently within each population and between sexes and among generations, due to nonadditive effects and a level of independence in the genetic control for traits. Our results emphasize the challenges to investigating and predicting phenotypic changes resulting from between-population outbreeding.

Projections in donor organs available for liver transplantation in the United States: 2014-2025.

Science.gov (United States)

Parikh, Neehar D; Hutton, David; Marrero, Wesley; Sanghani, Kunal; Xu, Yongcai; Lavieri, Mariel

2015-06-01

With the aging US population, demographic shifts, and obesity epidemic, there is potential for further exacerbation of the current liver donor shortage. We aimed to project the availability of liver grafts in the United States. We performed a secondary analysis of the Organ Procurement and Transplantation Network database of all adult donors from 2000 to 2012 and calculated the total number of donors available and transplanted donor livers stratified by age, race, and body mass index (BMI) group per year. We used National Health and Nutrition Examination Survey and Centers for Disease Control and Prevention historical data to stratify the general population by age, sex, race, and BMI. We then used US population age and race projections provided by the US Census Bureau and the Weldon Cooper Center for Public Service and made national and regional projections of available donors and donor liver utilization from 2014 to 2025. We performed sensitivity analyses and varied the rate of the rise in obesity, proportion of Hispanics, population growth, liver utilization rate, and donation after cardiac death (DCD) utilization. The projected adult population growth in the United States from 2014 to 2025 will be 7.1%. However, we project that there will be a 6.1% increase in the number of used liver grafts. There is marked regional heterogeneity in liver donor growth. Projections were significantly affected by changes in BMI, DCD utilization, and liver utilization rates but not by changes in the Hispanic proportion of the US population or changes in the overall population growth. Overall population growth will outpace the growth of available donor organs and thus potentially exacerbate the existing liver graft shortage. The projected growth in organs is highly heterogeneous across different United Network for Organ Sharing regions. Focused strategies to increase the liver donor pool are warranted. © 2015 American Association for the Study of Liver Diseases.

A demographic model to predict future growth of the Addo elephant population

OpenAIRE

A.M. Woodd

1999-01-01

An age-structured demographic model of the growth of the Addo elephant population was developed using parameters calculated from long-term data on the population. The model was used to provide estimates of future population growth. Expansion of the Addo Elephant National Park is currently underway, and the proposed target population size for elephant within the enlarged park is 2700. The model predicts that this population size will be reached during the year 2043, so that the Addo elephant p...

[Is it necessary to control the population growth of national minorities].

Science.gov (United States)

Tian, X Y

1981-02-01

In the process of Socialist construction and modernization, the development of the population of national minorities deserves our attention because it is directly related to the economic and cultural development in the areas inhabited by such national minorities, and it has a great impact on the welfare and future of those people. Moreover, the population growth of the minorities is a key factor in the national population control strategy. A rapid population growth among the minorities has caused serious problems in distribution of farm land and food supply, low personal income, a rise in the unemployment rate, and a rise in the illiteracy rate. This has prevented a rise in the living standard among the minority population. In order to prevent and solve population problems among the minorities, we must take appropriate measures according to local conditions to control population increases. Through popularization of education, population growth may be put under control. For those people who volunteer to practice family planning, the government should provide all kinds of assistance. At the same time, an effort is needed to introduce the necessity of improving birth quality, to popularize new methods of child birth, and to develop health and medical care for the general public, so that the quality of the minority population may be gradually improved.

A population growth trend analysis for Neotricula aperta, the snail intermediate host of Schistosoma mekongi, after construction of the Pak-Mun dam.

Directory of Open Access Journals (Sweden)

Stephen W Attwood

2013-11-01

Full Text Available The Pak-Mun dam is a controversial hydro-power project on the Mun River in Northeast Thailand. The dam is sited in a habitat of the freshwater snail Neotricula aperta, which is the intermediate host for the parasitic blood-fluke Schistosoma mekongi causing Mekong schistosomiasis in humans in Cambodia and Laos. Few data are available which can be used to assess the effects of water resource development on N. aperta. The aim of this study was to obtain data and to analyze the possible impact of the dam on N. aperta population growth.Estimated population densities were recorded for an N. aperta population in the Mun River 27 km upstream of Pak-Mun, from 1990 to 2011. The Pak-Mul dam began to operate in 1994. Population growth was modeled using a linear mixed model expression of a modified Gompertz stochastic state-space exponential growth model. The N. aperta population was found to be quite stable, with the estimated growth parameter not significantly different from zero. Nevertheless, some marked changes in snail population density were observed which were coincident with changes in dam operation policy.The study found that there has been no marked increase in N. aperta population growth following operation of the Pak-Mun dam. The analysis did indicate a large and statistically significant increase in population density immediately after the dam came into operation; however, this increase was not persistent. The study has provided the first vital baseline data on N. aperta population behavior near to the Pak-Mun dam and suggests that the operation policy of the dam may have an impact on snail population density. Nevertheless, additional studies are required for other N. aperta populations in the Mun River and for an extended time series, to confirm or refine the findings of this work.

Adapting to Population Growth: The Evolutionary Alternative to Malthus

Directory of Open Access Journals (Sweden)

Axel Kristinsson

2016-06-01

Full Text Available A long-standing debate on the dynamics of population growth in human history has become polarized between a Malthusian stance and a Boserupian one. The former tends to view population growth as limited by carrying capacity, dependent on environment and technology, whereas the latter sees population growth itself as a major inducement to social, economic and technological developments. In this paper the authors experiment with approaching this debate by using recent developments in evolutionary theory. According to these, evolutionary principles, as expounded by Charles Darwin and subsequent evolutionary scientists, apply not only to biological evolution but also to social or cultural evolution. Here, the role of genes is taken over by culture and, since culture is much more pliable than our DNA, evolution speeds up. As the only organisms on Earth whose evolution relies as heavily on culture as on genes, humans have become extremely adaptable. Their hyper-adaptability suggest that humans, through their cultural evolution, have managed increasingly to adapt to their own growing population, thus succeeding in accommodating ever-growing numbers. This hypothesis fits the Boserupian approach to population very well but less so the Malthusian one, perhaps indicating a gradual shift from a Malthusian regime to a Boserupian one in human history. The hypothesis is discussed and examined through four case studies: The beginning of farming around Göbekli Tepe in southeast Turkey, the productive farming systems of Tiwanaku in South America, the population crisis of late medieval and early modern Iceland, and the ‘collapse’ of Rapa Nui (Easter Island.

Environmental vs Demographic Stochasticity in Population Growth

OpenAIRE

Braumann, C. A.

2010-01-01

Compares the effect on population growth of envinonmental stochasticity (random environmental variations described by stochastic differential equations) with demographic stochasticity (random variations in births and deaths described by branching processes and birth-and-death processes), in the density-independent and the density-dependent cases.

A demographic model to predict future growth of the Addo elephant population

Directory of Open Access Journals (Sweden)

A.M. Woodd

1999-07-01

Full Text Available An age-structured demographic model of the growth of the Addo elephant population was developed using parameters calculated from long-term data on the population. The model was used to provide estimates of future population growth. Expansion of the Addo Elephant National Park is currently underway, and the proposed target population size for elephant within the enlarged park is 2700. The model predicts that this population size will be reached during the year 2043, so that the Addo elephant population can continue to increase for a further 44 years before its target size within the enlarged park is attained.

Parameter Estimates in Differential Equation Models for Population Growth

Science.gov (United States)

Winkel, Brian J.

2011-01-01

We estimate the parameters present in several differential equation models of population growth, specifically logistic growth models and two-species competition models. We discuss student-evolved strategies and offer "Mathematica" code for a gradient search approach. We use historical (1930s) data from microbial studies of the Russian biologist,…

The role of population on economic growth and development: evidence from developing countries

OpenAIRE

Atanda, Akinwande A.; Aminu, Salaudeen B.; Alimi, Olorunfemi Y.

2012-01-01

The precise relationship between population growth and per capita income has been inconclusive in the literature and the nexus has been found not clearly explain the determinants of rapid population growth in developing countries that lacks fertility control and management framework. This forms the rationale for this study to access the trend of factors that influence rapid population growth in developing countries between 1980 and 2010. This paper examined the comparative trend review of pop...

Using an integral projection model to assess the effect of temperature on the growth of gilthead seabream Sparus aurata.

Science.gov (United States)

Heather, F J; Childs, D Z; Darnaude, A M; Blanchard, J L

2018-01-01

Accurate information on the growth rates of fish is crucial for fisheries stock assessment and management. Empirical life history parameters (von Bertalanffy growth) are widely fitted to cross-sectional size-at-age data sampled from fish populations. This method often assumes that environmental factors affecting growth remain constant over time. The current study utilized longitudinal life history information contained in otoliths from 412 juveniles and adults of gilthead seabream, Sparus aurata, a commercially important species fished and farmed throughout the Mediterranean. Historical annual growth rates over 11 consecutive years (2002-2012) in the Gulf of Lions (NW Mediterranean) were reconstructed to investigate the effect of temperature variations on the annual growth of this fish. S. aurata growth was modelled linearly as the relationship between otolith size at year t against otolith size at the previous year t-1. The effect of temperature on growth was modelled with linear mixed effects models and a simplified linear model to be implemented in a cohort Integral Projection Model (cIPM). The cIPM was used to project S. aurata growth, year to year, under different temperature scenarios. Our results determined current increasing summer temperatures to have a negative effect on S. aurata annual growth in the Gulf of Lions. They suggest that global warming already has and will further have a significant impact on S. aurata size-at-age, with important implications for age-structured stock assessments and reference points used in fisheries.

Adult survival and population growth rate in Colorado big brown bats (Eptesicus fuscus)

Science.gov (United States)

O'Shea, T.J.; Ellison, L.E.; Stanley, T.R.

2011-01-01

We studied adult survival and population growth at multiple maternity colonies of big brown bats (Eptesicus fuscus) in Fort Collins, Colorado. We investigated hypotheses about survival using information-theoretic methods and mark-recapture analyses based on passive detection of adult females tagged with passive integrated transponders. We constructed a 3-stage life-history matrix model to estimate population growth rate (??) and assessed the relative importance of adult survival and other life-history parameters to population growth through elasticity and sensitivity analysis. Annual adult survival at 5 maternity colonies monitored from 2001 to 2005 was estimated at 0.79 (95% confidence interval [95% CI] = 0.77-0.82). Adult survival varied by year and roost, with low survival during an extreme drought year, a finding with negative implications for bat populations because of the likelihood of increasing drought in western North America due to global climate change. Adult survival during winter was higher than in summer, and mean life expectancies calculated from survival estimates were lower than maximum longevity records. We modeled adult survival with recruitment parameter estimates from the same population. The study population was growing (?? = 1.096; 95% CI = 1.057-1.135). Adult survival was the most important demographic parameter for population growth. Growth clearly had the highest elasticity to adult survival, followed by juvenile survival and adult fecundity (approximately equivalent in rank). Elasticity was lowest for fecundity of yearlings. The relative importances of the various life-history parameters for population growth rate are similar to those of large mammals. ?? 2011 American Society of Mammalogists.

1 2 POPULATION GROWTH AND THE DILEMMA OF RURAL LIFE ...

African Journals Online (AJOL)

Dr Ike

The high as well as the unrestrained population growth rate of the country has, to a ... that it stimulates business and general economic growth cycles and therefore .... The privilege and opportunity of acquiring functional education, for instance ...

Linking individual phenotype to density-dependent population growth: the influence of body size on the population dynamics of malaria vectors

Science.gov (United States)

Russell, Tanya L.; Lwetoijera, Dickson W.; Knols, Bart G. J.; Takken, Willem; Killeen, Gerry F.; Ferguson, Heather M.

2011-01-01

Understanding the endogenous factors that drive the population dynamics of malaria mosquitoes will facilitate more accurate predictions about vector control effectiveness and our ability to destabilize the growth of either low- or high-density insect populations. We assessed whether variation in phenotypic traits predict the dynamics of Anopheles gambiae sensu lato mosquitoes, the most important vectors of human malaria. Anopheles gambiae dynamics were monitored over a six-month period of seasonal growth and decline. The population exhibited density-dependent feedback, with the carrying capacity being modified by rainfall (97% wAICc support). The individual phenotypic expression of the maternal (p = 0.0001) and current (p = 0.040) body size positively influenced population growth. Our field-based evidence uniquely demonstrates that individual fitness can have population-level impacts and, furthermore, can mitigate the impact of exogenous drivers (e.g. rainfall) in species whose reproduction depends upon it. Once frontline interventions have suppressed mosquito densities, attempts to eliminate malaria with supplementary vector control tools may be attenuated by increased population growth and individual fitness. PMID:21389034

Soil science, population growth and food production: some historical developments

NARCIS (Netherlands)

Hartemink, A.E.

2007-01-01

The world¿s population has doubled since 1960. Currently, the developing world accounts for about 95% of the population growth with Africa as the world¿s fastest growing continent. The growing population has many implications but most of all it requires an increase in agricultural production to meet

Growth of rural population in Punjab, 1971-81.

Science.gov (United States)

Gill, M S

1987-01-01

Except for the decade 1941-1951, in which Punjab's population declined because of a huge exchange of population between India and Pakistan and a large loss of life, the decade 1971-1981 was the 1st decade since 1911 to experience a deceleration in the growth rate of the rural population of Punjab, India. The deceleration was due to out-migration to urban areas. The scheduled caste population increased 28.37% between 1971 and 1981, while the nonscheduled caste population increased by only 13.32%, which was considerably below the rate of natural increase. Nonscheduled castes had experienced substantial out-migration because of 1) improved transport and communication facilities which enabled them to move to urban centers; 2) mechanization of main farming operations and easy availability of migrant laborers which lessened the need for family labor; 3) the rise of a relatively mobile younger generation with a high literacy rate; 4) rapidly decreasing land holdings which strengthened the push factor in the countryside; and 5) rising aspirations, especially among the younger generation. In 1981, Sikhs constituted 71.3% of the rural population in Punjab, followed by Hindus (26.51%), Christians (1.25%), and Muslims (.89%). From 1971-1981, Muslims experienced the greatest increase (49.29%). Sikhs grew by 20.74% and Hindus by 9.02%. The Sikhs high growth rate was due to 1) a new technique for counting religious affiliation in which all members of a household are considered the same religion as the head of household and 2) conversion of Hindus to Sikhism. Hindus had a low growth rate because 1) the new method of counting religious affiliation and 2) rural-urban migration. The area with the lowest population increase resulted from industrialists and other nonagriculturists buying farmland, causing the agriculturists to move away to less desirable land. Conclusions are 1) the sharp rural-urban division along religious lines should be lessened, 2) Sikhs' lag in urbanization and

Constant savings rates and quasi-arithmetic population growth under exhaustible resource constraints

NARCIS (Netherlands)

Asheim, G.B.; Buchholz, W.; Hartwick, J.M.; Mitra, T.; Withagen, C.A.A.M.

2007-01-01

In the Dasgupta–Heal–Solow–Stiglitz (DHSS) model of capital accumulation and resource depletion we show the following equivalence: if an efficient path has constant (gross and net of population growth) savings rates, then population growth must be quasi-arithmetic and the path is a maximin or a

Trends in the growth of population and labour force in Pakistan.

Science.gov (United States)

Hashmi, S S

1990-01-01

Trends in the growth of the population and labor force in Pakistan are examined and future prospects for growth of population and labor, particularly agriculture, are estimated. The definition of labor force as employed or seeking work after a short period of employment has led to a great disparity in results for women in the labor force. Past trends in population growth reflected a growth rate of 1.6% for the 1950's, and 2.4% in 1960. The population rose to 84.3 million in 1981 from 42.6 million in 1961, which intercensally was an increase of 3.6% per annum for 1961-72 and 3.1% per annum for 1972-81. The estimated rate for 1981-86 was 2.9%/year. The rural population doubled and the urban tripled. There was a net migration of 2.123 million to urban areas reported in the 1981 census. There is also evidence of a high sex ratio. Balochistan (7.1%) and Sindh (3.6%) provinces have the highest growth rates. Although the largest population is in the Punjab, the growth is the lowest at 2.7%. The population is primarily young -- 44.5% 15 years in 1981, which is the highest in the world. Under high, medium, and low levels of fertility, prospective trends are estimated for 2006 and 2031, and by sex every 5 years from 1981. Population under high fertility is expected to reach 270 million by 2031, which is 3.39 persons/hectare. The population/hectare of land under cultivation was 4.25 in 1981 and is expected to rise to 13.49 persons/hectare in 2031. 11 million acres could be brought under cultivation to reduce the ratio. However, there are ecological considerations as well as an employment problem. The dependency ratio under the high variant will decline from 76.8 persons 0-14 and 65 years/100 persons 15-64 years in 1986 to 70.3 in 2006 which is still considerably higher than other developing countries. It is suggested that replacement level fertility be attained as soon as possible. Under low fertility, replacement level can be reached by 2011 with strong political commitment

Headship Rate for Population Projection in Johor Bahru

OpenAIRE

Rawan Nurfilzah Mohamad; Zainun Noor Yasmin; Alias Ahmad Rizal; Ibrahim Izzah Sofea

2017-01-01

Headship rate method is used to forecast population for housing demand. This paper presents the application of the method for forecasting population in Johor Bahru metropolitan city in Malaysia. Data used in the projection was based on census data of Johor Bahru provided by Department of Statistic Malaysia for the period of three years. Headship rate can be determined based on the ratio of head of household in age group by its age group total population. Hence, the purpose for this study is t...

Integral projection models for finite populations in a stochastic environment.

Science.gov (United States)

Vindenes, Yngvild; Engen, Steinar; Saether, Bernt-Erik

2011-05-01

Continuous types of population structure occur when continuous variables such as body size or habitat quality affect the vital parameters of individuals. These structures can give rise to complex population dynamics and interact with environmental conditions. Here we present a model for continuously structured populations with finite size, including both demographic and environmental stochasticity in the dynamics. Using recent methods developed for discrete age-structured models we derive the demographic and environmental variance of the population growth as functions of a continuous state variable. These two parameters, together with the expected population growth rate, are used to define a one-dimensional diffusion approximation of the population dynamics. Thus, a substantial reduction in complexity is achieved as the dynamics of the complex structured model can be described by only three population parameters. We provide methods for numerical calculation of the model parameters and demonstrate the accuracy of the diffusion approximation by computer simulation of specific examples. The general modeling framework makes it possible to analyze and predict future dynamics and extinction risk of populations with various types of structure, and to explore consequences of changes in demography caused by, e.g., climate change or different management decisions. Our results are especially relevant for small populations that are often of conservation concern.

The hydrocarbon era, world population growth and oil use -- a continuing geological challenge

International Nuclear Information System (INIS)

Townes, H.L.

1993-01-01

The world's use of oil, the relationship of world population growth to this use, and what the energy situation might be in the future is a challenge to the geologist. The earth's population doubled between 1930 and 1975 and a comparison of world petroleum use and population growth show similar upward curves. Of the annual fossil fuel resources used in the world, crude oil supplies over 40 percent of the total resources. Petroleum is a finite resource and a projection of world oil production indicates it will peak early in the 21st century. Assuming an ultimate recovery range of 2600 to 3000 billion barrels of oil, 750 billion barrels have already been produced, there are 1000 billion barrels in proven reserves, and 1000 billion barrels remaining to be discovered. The challenge to the geologist will be to find these hidden oil reserves. Recovering this 1000 billion barrels of new oil reserves will require large capital expenditures and, currently, only 60 percent of the capital needed to discover this oil is being spent. With the world's demand for oil increasing, world-wide exploration expenditures are actually decreasing. Simple economics indicates that the reason for this drop in expenditures is that the price of oil is too low to encourage investment. Low oil prices also discourage investment in the development of alternative fuels. There is plenty of oil now, but the world must look to the future and realize present usage rate cannot continue forever. 23 refs., 10 figs

Do Class III patients have a different growth spurt than the general population?

Science.gov (United States)

Lee, Yun-Sik; Lee, Shin-Jae; An, Hongseok; Donatelli, Richard E; Kim, Soo-Hwan

2012-11-01

Understanding the timing and length of the growth spurt of Class III prognathic patients is fundamental to the strategy of interceptive orthopedic orthodontics as well as to the timing of orthognathic surgery. Consequently, this study was undertaken to determine whether there are any significant differences in the stature growth pattern of Class III subjects compared with non-Class III subjects and the general population. Twelve-year longitudinal stature growth data were collected for 402 randomly selected adolescents in the general population, 55 Class III mandibular prognathic patients, and 37 non-Class III patients. The growth data were analyzed by using the traditional linear interpolation method and nonlinear growth functions. The 6 stature growth parameters were measured: age at takeoff, stature at takeoff, velocity at takeoff, age at peak height velocity, stature at peak height velocity, and velocity at peak height velocity. Comparisons in the stature growth parameters and 15 cephalometric variables among the general population, Class III subjects, and non-Class III subjects were made with multivariate analysis. Patients with Class III prognathism did not have different growth parameters compared with Class II subjects or the general population. This study does not allow meaningful conclusions with regard to the relationship of mandibular size and stature growth pattern. The application of nonlinear growth curves vs the traditional linear interpolation method was also discussed. Copyright © 2012 American Association of Orthodontists. Published by Mosby, Inc. All rights reserved.

Projection of radiation-induced cancer risks across time and populations

International Nuclear Information System (INIS)

Muirhead, C.R.

1991-01-01

Various methods can be used to project the risks of radiation-induced cancer estimated in cohort studies beyond the period of follow-up and to other populations. The choice of risk projection model is reviewed based on data from studies such as those of the Japanese atomic bomb survivors and UK ankylosing spondylitis patients given X ray therapy. Risk estimates applicable to a UK population are calculated on the basis of various models, including those developed by the BEIR V Committee. It is emphasised that the continued follow-up of populations such as the Japanese atomic bomb survivors is of great importance in estimating lifetime risks. (author)

A Role for M-Matrices in Modelling Population Growth

Science.gov (United States)

James, Glyn; Rumchev, Ventsi

2006-01-01

Adopting a discrete-time cohort-type model to represent the dynamics of a population, the problem of achieving a desired total size of the population under a balanced growth (contraction) and the problem of maintaining the desired size, once achieved, are studied. Properties of positive-time systems and M-matrices are used to develop the results,…

[The decline in population growth, income distribution, and economic recession].

Science.gov (United States)

Banguero, H

1983-05-01

This work uses Keynesian principles and an analysis of the Colombian population in the 1970s to argue that the Colombian policy of slowing population growth, which was adopted with the aim of improving the general welfare of the population, has had shortterm negative effects on effective demand and thus on the level of employment and welfare. These negative effects were caused by the inflexibility of income distribution, which prevented expansion of the internal market, complicated by the stagnant condition of the external sector and the budget deficit. The results of the Colombian case study demonstrate how the deceleration of population growth beginning in the 1960s had a significant impact on the levels of consumption and savings and on the patterns of consumption, leading to low levels of investment and little dynamism. Although the current Colombian economic recession is aggravated by contextual factors such as the world economic recession, the high cost of capital, the industrial recession, and declining food production among others, at the core of the crisis are longer term structural determinants such as the decline in the rate of population growth and the highly unequal distribution of income and wealth, which have contributed to a shrinking of the internal market for some types of goods. Given the unlikelihood of renewed rapid population growth, the Keynesian model suggests that the only alternative for increasing aggregate demand is state intervention through public spending and investment and reorientation of the financial system to achieve a dynamic redistribution of income. Based on these findings and on proposals of other analysts, a stragegy for revitalization is proposed which would imply a gradual income redistribution to allow increased consumption of mass produced goods by the low income groups. Direct consumption subsidies would be avoided because of their inflationary and import-expanding tendencies; rather, incentives and support would be

Inflation, GDP growth and population change in the USA

OpenAIRE

Ivan Kitov

2005-01-01

Inflation in the USA between 1960 and 2004 is studied in the framework of the revealed rigidity of the personal income distribution normalized to the total nominal GDP. Inflation is found to be a mechanism, which prevents changes in the relative incomes induced by economic growth and population changes - both in number and age structure. A model is developed linking CPI to GDP growth rate and relative change of the number of people of some specific age. The GDP growth rate is characterized by...

[Fifty years of population growth and absorbing manual labor in Brazil, 1950-2000].

Science.gov (United States)

Paiva, P D

1986-01-01

The economically active population has grown rapidly in Brazil, resulting either from population growth or increased female participation in the work force. This rhythm of growth will continue at least until the end of this century. The authors suggest that the impact of the recent decline in fertility will be moderate and will only affect the younger age groups. Despite the rapid growth of employment in the processing industry, the relative size of the so-called informal sector has remained stable since 1950. It is further predicted that, given the economically active population's rate of growth and the decrease in employment in agriculture, there will be a great demand for urban employment in the next 20 years.

Building Context with Tumor Growth Modeling Projects in Differential Equations

Science.gov (United States)

Beier, Julie C.; Gevertz, Jana L.; Howard, Keith E.

2015-01-01

The use of modeling projects serves to integrate, reinforce, and extend student knowledge. Here we present two projects related to tumor growth appropriate for a first course in differential equations. They illustrate the use of problem-based learning to reinforce and extend course content via a writing or research experience. Here we discuss…

Psychologists and the problem of population growth : Reply to Bridgeman

NARCIS (Netherlands)

Clayton, Susan; Carrico, Amanda; Steg, Linda; Swim, Janet K.; Bonnes, Mirilia; Devine-Wright, Patrick

2017-01-01

Bridgeman (2017) describes the important role of population growth in contributing to environmental problems. The present essay argues that population is an important component of human impact on the environment, but it must be considered in combination with consumption rates. A place-based

Age and growth of two populations of West Coast steenbras ...

African Journals Online (AJOL)

... density-dependent competition for food, or biochemical genetic variations between the two populations, are possible reasons for the geographic differences found in the growth rates and length-at-age. Slow growth and longevity are characteristics of West Coast steenbras that make it extremely susceptible to overfishing; ...

Controlling the Growth of Future LEO Debris Populations with Active Debris Removal

Science.gov (United States)

Liou, J.-C.; Johnson, N. L.; Hill, N. M.

2008-01-01

Active debris removal (ADR) was suggested as a potential means to remediate the low Earth orbit (LEO) debris environment as early as the 1980s. The reasons ADR has not become practical are due to its technical difficulties and the high cost associated with the approach. However, as the LEO debris populations continue to increase, ADR may be the only option to preserve the near-Earth environment for future generations. An initial study was completed in 2007 to demonstrate that a simple ADR target selection criterion could be developed to reduce the future debris population growth. The present paper summarizes a comprehensive study based on more realistic simulation scenarios, including fragments generated from the 2007 Fengyun-1C event, mitigation measures, and other target selection options. The simulations were based on the NASA long-term orbital debris projection model, LEGEND. A scenario, where at the end of mission lifetimes, spacecraft and upper stages were moved to 25-year decay orbits, was adopted as the baseline environment for comparison. Different annual removal rates and different ADR target selection criteria were tested, and the resulting 200-year future environment projections were compared with the baseline scenario. Results of this parametric study indicate that (1) an effective removal strategy can be developed based on the mass and collision probability of each object as the selection criterion, and (2) the LEO environment can be stabilized in the next 200 years with an ADR removal rate of five objects per year.

Population Growth Rate: Teaching Guide. Measures of Progress Poster Kit Number 2.

Science.gov (United States)

World Bank, Washington, DC.

This teaching guide accompanies the Population Growth Rate poster kit which is designed to teach students about population growth differences between rich and poor nations and about what people in developing countries are doing to help improve their quality of life. The guide is designed for use with: (1) a poster map of the world providing social…

Perturbation analysis of transient population dynamics using matrix projection models

DEFF Research Database (Denmark)

Stott, Iain

2016-01-01

Non-stable populations exhibit short-term transient dynamics: size, growth and structure that are unlike predicted long-term asymptotic stable, stationary or equilibrium dynamics. Understanding transient dynamics of non-stable populations is important for designing effective population management...... these methods to know exactly what is being measured. Despite a wealth of existing methods, I identify some areas that would benefit from further development....

Human population and atmospheric carbon dioxide growth dynamics: Diagnostics for the future

Science.gov (United States)

Hüsler, A. D.; Sornette, D.

2014-10-01

We analyze the growth rates of human population and of atmospheric carbon dioxide by comparing the relative merits of two benchmark models, the exponential law and the finite-time-singular (FTS) power law. The later results from positive feedbacks, either direct or mediated by other dynamical variables, as shown in our presentation of a simple endogenous macroeconomic dynamical growth model describing the growth dynamics of coupled processes involving human population (labor in economic terms), capital and technology (proxies by CO2 emissions). Human population in the context of our energy intensive economies constitutes arguably the most important underlying driving variable of the content of carbon dioxide in the atmosphere. Using some of the best databases available, we perform empirical analyses confirming that the human population on Earth has been growing super-exponentially until the mid-1960s, followed by a decelerated sub-exponential growth, with a tendency to plateau at just an exponential growth in the last decade with an average growth rate of 1.0% per year. In contrast, we find that the content of carbon dioxide in the atmosphere has continued to accelerate super-exponentially until 1990, with a transition to a progressive deceleration since then, with an average growth rate of approximately 2% per year in the last decade. To go back to CO2 atmosphere contents equal to or smaller than the level of 1990 as has been the broadly advertised goals of international treaties since 1990 requires herculean changes: from a dynamical point of view, the approximately exponential growth must not only turn to negative acceleration but also negative velocity to reverse the trend.

Rapid population growth and fragile environments: the sub-Saharan African and south Asian experience.

Science.gov (United States)

Caldwell, J C; Caldwell, P

1994-02-18

Case studies of the world's two poorest regions, sub-Saharan Africa and South Asia, were used to illustrate the compromised standard of living of the poor and environmental damage due to continued rapid population growth. The conclusion was that the livelihoods of the poor should not be endangered for preserving the living standards of richer people. Nations must not ignore the challenges of reducing population growth as fast as can be achieved. The transitional period over the next 50 years is the main concern, because population growth rates will be slowing. Rural population growth is expected to decline from 60% of total population growth in South Asia to 7% between 2000 and 2025; similarly the decline in sub-Saharan Africa would be from 50% to 15%. Over the past 30 years, food production in South Asia has kept pace with population growth. Sub-Saharan Africa has adopted food importation to meet demand. African problems are a low resource base, faster population growth, and the fact that governments and individuals are too poor to maintain soil fertility. Long-term studies of how much soil depletion will occur are not available for these regions, and local area studies are not as pessimistic. Transition policies are needed to put "people first in terms of engineered or directed population and ecological change." The six main issues are the following: 1) the Brundtland Commission appropriately identified poverty as the main cause and effect of environmental degradation because of the threat to survival; 2) the verdict is still out about whether food production will keep pace with population growth through economic growth and investment in agriculture; 3) empirical research is needed to examine local social and regulatory institutions and the possibility of reinforcing these mechanisms rather than instituting central controls; 4) central coercion or modernizing economic policies can destroy local level controls; 5) famine is a complex ecological phenomenon and the

International standards for fetal growth based on serial ultrasound measurements: the Fetal Growth Longitudinal Study of the INTERGROWTH-21st Project.

Science.gov (United States)

Papageorghiou, Aris T; Ohuma, Eric O; Altman, Douglas G; Todros, Tullia; Cheikh Ismail, Leila; Lambert, Ann; Jaffer, Yasmin A; Bertino, Enrico; Gravett, Michael G; Purwar, Manorama; Noble, J Alison; Pang, Ruyan; Victora, Cesar G; Barros, Fernando C; Carvalho, Maria; Salomon, Laurent J; Bhutta, Zulfiqar A; Kennedy, Stephen H; Villar, José

2014-09-06

In 2006, WHO produced international growth standards for infants and children up to age 5 years on the basis of recommendations from a WHO expert committee. Using the same methods and conceptual approach, the Fetal Growth Longitudinal Study (FGLS), part of the INTERGROWTH-21(st) Project, aimed to develop international growth and size standards for fetuses. The multicentre, population-based FGLS assessed fetal growth in geographically defined urban populations in eight countries, in which most of the health and nutritional needs of mothers were met and adequate antenatal care was provided. We used ultrasound to take fetal anthropometric measurements prospectively from 14 weeks and 0 days of gestation until birth in a cohort of women with adequate health and nutritional status who were at low risk of intrauterine growth restriction. All women had a reliable estimate of gestational age confirmed by ultrasound measurement of fetal crown-rump length in the first trimester. The five primary ultrasound measures of fetal growth--head circumference, biparietal diameter, occipitofrontal diameter, abdominal circumference, and femur length--were obtained every 5 weeks (within 1 week either side) from 14 weeks to 42 weeks of gestation. The best fitting curves for the five measures were selected using second-degree fractional polynomials and further modelled in a multilevel framework to account for the longitudinal design of the study. We screened 13,108 women commencing antenatal care at less than 14 weeks and 0 days of gestation, of whom 4607 (35%) were eligible. 4321 (94%) eligible women had pregnancies without major complications and delivered live singletons without congenital malformations (the analysis population). We documented very low maternal and perinatal mortality and morbidity, confirming that the participants were at low risk of adverse outcomes. For each of the five fetal growth measures, the mean differences between the observed and smoothed centiles for the 3rd

Population Growth, Available Resources, and Quality of Life： China＇s Post-Reform Economic Development

Institute of Scientific and Technical Information of China (English)

Tim Futing Liao; Hua Qin

2012-01-01

Two opposing intellectual traditions and their contem- porary developments regarding the relations among population, available resources, and quality of life as reflected in economic growth are reviewed. What is at issue is whether population growth is detrimental to or beneficial for economic development. Neither of the extreme views gives a complete picture of the interplay among population, resources, and quality of life. Following previ- ous literature on the topic, this paper establishes a more balanced approach that considers the function linking population and quality of life not constant but variable and regards the limitedness of resources as not absolute but relative to regions and societies. The proposed approach is more flexible in better explaining the relation between population and economic growth. China is examined as a case in point to shed light on the interaction of population growth, economic development, and available resources, and its recent post-economic reform experiences showcase the appropriateness of the synthetic approach.

Morbidity, rickets and long-bone growth in post-medieval Britain--a cross-population analysis.

Science.gov (United States)

Pinhasi, R; Shaw, P; White, B; Ogden, A R

2006-01-01

Vitamin D deficiency rickets is associated with skeletal deformities including swollen rib junctions, bowing of the legs, and the flaring and fraying of the wrist and long-bone metaphyses. There is, however, scarce information on the direct effect of rickets on skeletal growth in either present or past populations. The study investigated the effect of vitamin D deficiency rickets on long-bone growth in two post-medieval skeletal populations from East London (Broadgate and Christ Church Spitalfields). Subsequently, inter-population growth variations in relation to non-specific environmental stress (dental enamel defects), industrialization, urbanization and socio-economic status during infancy (birth to 3 years) and early childhood (3-7 years) were examined. Data on long-bone diaphyseal length dimensions and stress indicators of 234 subadults from Anglo-Saxon, late medieval and post-medieval archaeological skeletal samples were analysed using both linear and non-linear growth models. Rickets had no effect on the growth curves for any of the long bones studied. However, pronounced variations in growth between the four populations were noted, mainly during infancy. The diaphyseal length of long bones of Broadgate were significantly smaller-per-age than those of Spitalfields and the other samples up to the age of 4 years, and were associated with a high prevalence of enamel defects during early infancy. Socio-economic status, rather than urbanization, industrialization or rickets, was the central factor behind the observed differences in growth among the post-medieval populations. The observed inter-population growth variations were only significant during infancy.

Population growth of Mexican free-tailed bats (Tadarida brasiliensis mexicana predates human agricultural activity

Directory of Open Access Journals (Sweden)

Cox Murray P

2011-04-01

Full Text Available Abstract Background Human activities, such as agriculture, hunting, and habitat modification, exert a significant effect on native species. Although many species have suffered population declines, increased population fragmentation, or even extinction in connection with these human impacts, others seem to have benefitted from human modification of their habitat. Here we examine whether population growth in an insectivorous bat (Tadarida brasiliensis mexicana can be attributed to the widespread expansion of agriculture in North America following European settlement. Colonies of T. b. mexicana are extremely large (~106 individuals and, in the modern era, major agricultural insect pests form an important component of their food resource. It is thus hypothesized that the growth of these insectivorous bat populations was coupled to the expansion of agricultural land use in North America over the last few centuries. Results We sequenced one haploid and one autosomal locus to determine the rate and time of onset of population growth in T. b. mexicana. Using an approximate Maximum Likelihood method, we have determined that T. b. mexicana populations began to grow ~220 kya from a relatively small ancestral effective population size before reaching the large effective population size observed today. Conclusions Our analyses reject the hypothesis that T. b. mexicana populations grew in connection with the expansion of human agriculture in North America, and instead suggest that this growth commenced long before the arrival of humans. As T. brasiliensis is a subtropical species, we hypothesize that the observed signals of population growth may instead reflect range expansions of ancestral bat populations from southern glacial refugia during the tail end of the Pleistocene.

Urban Ecology: Patterns of Population Growth and Ecological Effects

Science.gov (United States)

Wayne C. Zipperer; Steward T.A. Pickett

2012-01-01

Currently, over 50% of the world’s population lives in urban areas. By 2050, this estimate is expected to be 70%. This urban growth, however, is not uniformly distributed around the world. The majority of it will occur in developing nations and create megacities whose populations exceed at least 10 million people. Not all urban areas, however, are growing. Some are...

Life history and spatial determinants of somatic growth dynamics in Komodo dragon populations

OpenAIRE

Laver, Rj; Purwandana, D; Ariefiandy, A; Imansyah, J; Forsyth, D; Ciofi, C; Jessop, Ts

2012-01-01

Somatic growth patterns represent a major component of organismal fitness and may vary among sexes and populations due to genetic and environmental processes leading to profound differences in life-history and demography. This study considered the ontogenic, sex-specific and spatial dynamics of somatic growth patterns in ten populations of the world's largest lizard the Komodo dragon (Varanus komodoensis). The growth of 400 individual Komodo dragons was measured in a capture-mark-recapture st...

On the growth of primary industry and population of China’s counties

Science.gov (United States)

Xie, Wen-Jie; Gu, Gao-Feng; Zhou, Wei-Xing

2010-09-01

The growth dynamics of complex organizations have attracted much interest of econophysicists and sociophysicists in recent years. However, most of the studies are done for developed countries. We investigate the growth dynamics of the primary industry and the population of 2079 counties in mainland China using the data from the China County Statistical Yearbooks from 2000 to 2006. We find that the annual growth rates are distributed according to Student’s t distribution with the tail exponent less than 2. We find power-law relationships between the sample standard deviation of the growth rates and the initial size. The scaling exponent is less than 0.5 for the primary industry and close to 0.5 for the population.

Population growth, interest rate, and housing tax in the transitional China

Science.gov (United States)

He, Ling-Yun; Wen, Xing-Chun

2017-03-01

This paper combines and develops the models in Lastrapes (2002) and Mankiw and Weil (1989), which enables us to analyze the effects of interest rate and population growth shocks on housing price in one integrated framework. Based on this model, we carry out policy simulations to examine whether the housing (stock or flow) tax reduces the housing price fluctuations caused by interest rate or population growth shocks. Simulation results imply that the choice of housing tax tools depends on the kind of shock that housing market faces. In the situation where the housing price volatility is caused by the population growth shock, the flow tax can reduce the volatility of housing price while the stock tax makes no difference to it. If the shock is resulting from the interest rate, the policy maker should not impose any kind of the housing taxes. Furthermore, the effect of one kind of the housing tax can be strengthened by that of the other type of housing tax.

Income-based projections of water footprint of food consumption in Uzbekistan

Science.gov (United States)

Djanibekov, Nodir; Frohberg, Klaus; Djanibekov, Utkur

2013-11-01

Assessing future water requirements for feeding the growing population of Central Asia can improve understanding of the projected water supply scenarios in the region. Future water requirements will be partially determined by the dietary habits of the populations, and are thus responsive to significant variation of income levels. Using Uzbekistan as an example, this study projects the water footprints of income driven changes on the population's diet in Central Asia. To reveal the influence of large income changes on dietary habits a Normalized Quadratic-Quadratic Expenditure System was calibrated and applied to data from 2009. The national water footprints of food consumption in Uzbekistan were projected until 2034 by applying the parameterized demand system to estimate the respective water footprint values. The results showed that for Uzbekistan the projected increase in the food consumption water footprint would be primarily linked to income growth rather than population growth. Due to the high water footprint of common food products, the composition of the population's diet, and responsiveness to income, economic growth is expected to put greater pressure on water resources in Uzbekistan unless proper measures are undertaken.

Demographics of an experimentally released population of elk in Great Smoky Mountains National Park

Science.gov (United States)

Murrow, Jennifer L.; Clark, Joseph D.; Delozier, E. Kim

2009-01-01

We assessed the potential for reestablishing elk (Cervus elaphus) in Great Smoky Mountains National Park (GSMNP), USA, by estimating vital rates of experimentally released animals from 2001 to 2006. Annual survival rates for calves ranged from 0.333 to 1.0 and averaged 0.592. Annual survival for subadult and adult elk (i.e., ≥1 yr of age) ranged from 0.690 to 0.933, depending on age and sex. We used those and other vital rates to model projected population growth and viability using a stochastic individual-based model. The annual growth rate (λ) of the modeled population over a 25-year period averaged 0.996 and declined from 1.059 the first year to 0.990 at year 25. The modeled population failed to attain a positive 25-year mean growth rate in 46.0% of the projections. Poor calf recruitment was an important determinant of low population growth. Predation by black bears (Ursus americanus) was the dominant calf mortality factor. Most of the variance of growth projections was due to demographic variation resulting from the small population size (n  =  61). Management actions such as predator control may help increase calf recruitment, but our projections suggest that the GSMNP elk population may be at risk for some time because of high demographic variation.

Using a laboratory-based growth model to estimate mass- and temperature-dependent growth parameters across populations of juvenile Chinook Salmon

Science.gov (United States)

Perry, Russell W.; Plumb, John M.; Huntington, Charles

2015-01-01

To estimate the parameters that govern mass- and temperature-dependent growth, we conducted a meta-analysis of existing growth data from juvenile Chinook Salmon Oncorhynchus tshawytscha that were fed an ad libitum ration of a pelleted diet. Although the growth of juvenile Chinook Salmon has been well studied, research has focused on a single population, a narrow range of fish sizes, or a narrow range of temperatures. Therefore, we incorporated the Ratkowsky model for temperature-dependent growth into an allometric growth model; this model was then fitted to growth data from 11 data sources representing nine populations of juvenile Chinook Salmon. The model fit the growth data well, explaining 98% of the variation in final mass. The estimated allometric mass exponent (b) was 0.338 (SE = 0.025), similar to estimates reported for other salmonids. This estimate of b will be particularly useful for estimating mass-standardized growth rates of juvenile Chinook Salmon. In addition, the lower thermal limit, optimal temperature, and upper thermal limit for growth were estimated to be 1.8°C (SE = 0.63°C), 19.0°C (SE = 0.27°C), and 24.9°C (SE = 0.02°C), respectively. By taking a meta-analytical approach, we were able to provide a growth model that is applicable across populations of juvenile Chinook Salmon receiving an ad libitum ration of a pelleted diet.

Modeling the growth of individuals in plant populations: local density variation in a strand population of Xanthium strumarium (Asteraceae).

Science.gov (United States)

Weiner, J; Kinsman, S; Williams, S

1998-11-01

We studied the growth of individual Xanthium strumarium plants growing at four naturally occurring local densities on a beach in Maine: (1) isolated plants, (2) pairs of plants ≤1 cm apart, (3) four plants within 4 cm of each other, and (4) discrete dense clumps of 10-39 plants. A combination of nondestructive measurements every 2 wk and parallel calibration harvests provided very good estimates of the growth in aboveground biomass of over 400 individual plants over 8 wk and afforded the opportunity to fit explicit growth models to 293 of them. There was large individual variation in growth and resultant size within the population and within all densities. Local crowding played a role in determining plant size within the population: there were significant differences in final size between all densities except pairs and quadruples, which were almost identical. Overall, plants growing at higher densities were more variable in growth and final size than plants growing at lower densities, but this was due to increased variation among groups (greater variation in local density and/or greater environmental heterogeneity), not to increased variation within groups. Thus, there was no evidence of size asymmetric competition in this population. The growth of most plants was close to exponential over the study period, but half the plants were slightly better fit by a sigmoidal (logistic) model. The proportion of plants better fit by the logistic model increased with density and with initial plant size. The use of explicit growth models over several growth intervals to describe stand development can provide more biological content and more statistical power than "growth-size" methods that analyze growth intervals separately.

Population Growth and Its Expression in Spatial Built-up Patterns: The Sana’a, Yemen Case Study

Directory of Open Access Journals (Sweden)

Gunter Zeug

2010-04-01

Full Text Available In light of rapid global urbanisation, monitoring and mapping of urban and population growth is of great importance. Population growth in Sana’a was investigated for this reason. The capital of the Republic of Yemen is a rapidly growing middle sized city where the population doubles almost every ten years. Satellite data from four different sensors were used to explore urban growth in Sana’a between 1989 and 2007, assisted by topographic maps and cadastral vector data. The analysis was conducted by delineating the built-up areas from the various optical satellite data, applying a fuzzy-rule-based composition of anisotropic textural measures and interactive thresholding. The resulting datasets were used to analyse urban growth and changes in built-up density per district, qualitatively as well as quantitatively, using a geographic information system. The built-up area increased by 87 % between 1989 and 2007. Built-up density has increased in all areas, but particularly in the northern and southern suburban districts, also reflecting the natural barrier of surrounding mountain ranges. Based on long-term population figures, geometric population growth was assumed. This hypothesis was used together with census data for 1994 and 2004 to estimate population figures for 1989 and 2007, resulting in overall growth of about 240%. By joining population figures to district boundaries, the spatial patterns of population distribution and growth were examined. Further, urban built-up growth and population changes over time were brought into relation in order to investigate changes in population density per built-up area. Population densities increased in all districts, with the greatest density change in the peripheral areas towards the North. The results reflect the pressure on the city’s infrastructure and natural resources and could contribute to sustainable urban planning in the city of Sana’a.

Population, internal migration, and economic growth: an empirical analysis.

Science.gov (United States)

Moreland, R S

1982-01-01

The role of population growth in the development process has received increasing attention during the last 15 years, as manifested in the literature in 3 broad categories. In the 1st category, the effects of rapid population growth on the growth of income have been studied with the use of simulation models, which sometimes include endogenous population growth. The 2nd category of the literature is concerned with theoretical and empirical studies of the economic determinants of various demographic rates--most usually fertility. Internal migration and dualism is the 3rd population development category to recieve attention. An attempt is made to synthesize developments in these 3 categories by estimating from a consistent set of data a 2 sector economic demographic model in which the major demographic rates are endogenous. Due to the fact that the interactions between economic and demographic variables are nonlinear and complex, the indirect effects of changes in a particular variable may depend upon the balance of numerical coefficients. For this reason it was felt that the model should be empirically grounded. A brief overview of the model is provided, and the model is compared to some similar existing models. Estimation of the model's 9 behavior equations is discussed, followed by a "base run" simulation of a developing country "stereotype" and a report of a number of policy experiments. The relatively new field of economic determinants of demographic variables was drawn upon in estimating equations to endogenize demographic phenomena that are frequently left exogenous in simulation models. The fertility and labor force participation rate functions are fairly standard, but a step beyong existing literature was taken in the life expectancy and intersectorial migration equations. On the economic side, sectoral savings functions were estimated, and it was found that the marginal propensity to save is lower in agriculture than in nonagriculture. Testing to see the

Contributions of long-distance dispersal to population growth in colonising Pinus ponderosa populations.

Science.gov (United States)

Lesser, Mark R; Jackson, Stephen T

2013-03-01

Long-distance dispersal is an integral part of plant species migration and population development. We aged and genotyped 1125 individuals in four disjunct populations of Pinus ponderosa that were initially established by long-distance dispersal in the 16th and 17th centuries. Parentage analysis was used to determine if individuals were the product of local reproductive events (two parents present), long-distance pollen dispersal (one parent present) or long-distance seed dispersal (no parents present). All individuals established in the first century at each site were the result of long-distance dispersal. Individuals reproduced at younger ages with increasing age of the overall population. These results suggest Allee effects, where populations were initially unable to expand on their own, and were dependent on long-distance dispersal to overcome a minimum-size threshold. Our results demonstrate that long-distance dispersal was not only necessary for initial colonisation but also to sustain subsequent population growth during early phases of expansion. © 2012 Blackwell Publishing Ltd/CNRS.

Population growth, economic security, and cultural change in wilderness counties

Science.gov (United States)

Paul A. Lorah

2000-01-01

A familiar version of the “jobs versus the environment” argument asserts that wilderness areas limit economic growth by locking up potentially productive natural resources. Analysis of the development paths of rural Western counties shows that this is unlikely: the presence of Wilderness is correlated with income, employment and population growth. Similarly, Wilderness...

An exponential growth model with decreasing r captures bottom-up effects on the population growth of Aphis glycines Matsumura (Hemiptera: Aphididae)

NARCIS (Netherlands)

Costamagna, A.C.; Werf, van der W.; Bianchi, F.J.J.A.; Landis, D.A.

2007-01-01

1 There is ample evidence that the life history and population dynamics of aphids are closely linked to plant phenology. Based on life table studies, it has been proposed that the growth of aphid populations could be modeled with an exponential growth model, with r decreasing linearly with time.

Selection for life-history traits to maximize population growth in an invasive marine species

DEFF Research Database (Denmark)

Jaspers, Cornelia; Marty, Lise; Kiørboe, Thomas

2018-01-01

Species establishing outside their natural range, negatively impacting local ecosystems, are of increasing global concern. They often display life-history features characteristic for r-selected populations with fast growth and high reproduction rates to achieve positive population growth rates (r...

Influence of Plant Population and Nitrogen-Fertilizer at Various Levels on Growth and Growth Efficiency of Maize

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M. I. Tajul

2013-01-01

Full Text Available Field experiments were conducted to evaluate plant population and N-fertilizer effects on yield and yield components of maize (Zea mays L.. Three levels of plant populations (53000, 66000, and 800000 plants ha−1 corresponding to spacings of 75 × 25, 60 × 25, and 50 × 25 cm and 4 doses of N (100, 140, 180, and 220 kg ha−1 were the treatment variables. Results revealed that plant growth, light interception (LI, yield attributes, and grain yield varied significantly due to the variations in population density and N-rates. Crop growth rate (CGR was the highest with the population of 80,000 ha−1 receiving 220 kg N ha−1, while relative growth rate (RGR showed an opposite trend of CGR. Light absorption was maximum when most of densely populated plant received the highest amount of N (220 kg N ha−1. Response of soil-plant-analysis development (SPAD value as well as N-content to N-rates was found significant. Plant height was the maximum at the lowest plant density with the highest amount of N. Plants that received 180 kg N ha−1 with 80,000 plants ha−1 had larger foliage, greater SPAD value, and higher amount of grains cob−1 that contributed to the maximum yield (5.03 t ha−1 and the maximum harvest index (HI compared to the plants in other treatments.

Projected Population Proximity Indices (30km for 2005, 2030 & 2050

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Neil S. Alexander

2013-07-01

Full Text Available This data package includes nine population proximity index layers for 2005, 2030 and 2050, for rural, urban and total populations.  The layers are distributed as 1km GeoTIFFs and GeoJPGss at 1km. The aim of these layers is to describe the population which may be likely to visit a specific locality where access is determined by Euclidean distance. By using the layers alongside other geographic datasets relating to disease risk it may help identify where people may come into contact with a disease.  Human population layers are often used in models to identify risk areas where humans and viruses interact, however most pathogens are not restricted to areas of human habitation: many are found in lesser populated areas such as forests.  This dataset will help identify less populated areas that may well still receive high visitor numbers. The layers have been projected to 2030 and 2050 to enable projections of human/disease interfaces in the medium-term which are required to inform policy makers at country and continental level. Urban and rural populations have been separated into individual layers as in some cases it is useful to distinguish between the behaviour and associated risks attributed to the different population segments.  There may be a different risk of contacting diseases in rural habitats for rural workers than for than urban visitors.

Geographically distinct Ceratophyllum demersum populations differ in growth, photosynthetic responses and phenotypic plasticity to nitrogen availability

DEFF Research Database (Denmark)

Hyldgaard, Benita; Sorrell, Brian Keith; Olesen, Birgit

2012-01-01

from New Zealand (NZ) and a noninvasive population from Denmark (DK). The populations were compared with a focus on both morphological and physiological traits. The NZ population had higher relative growth rates (RGRs) and photosynthesis rates (Pmax) (range: RGR, 0.06–0.08 per day; Pmax, 200–395 µmol O......2 g–1 dry mass (DM) h–1) compared with the Danish population (range: RGR, 0.02–0.05 per day; Pmax, 88–169 µmol O2 g–1 DM h–1). The larger, faster-growing NZ population also showed higher plasticity than the DK population in response to nitrogen in traits important for growth. Hence, the observed...... differences in growth behaviour between the two populations are a result of genetic differences and differences in their level of plasticity. Here, we show that two populations of the same species from similar climates but different geographical areas can differ in several ecophysiological traits after growth...

Impact of Personal Growth Projects on Leadership Identity Development

Science.gov (United States)

Odom, Summer F.; Boyd, Barry L.; Williams, Jennifer

2012-01-01

Within personal leadership education courses, leadership educators should include experiences which help students develop themselves as leaders. In this article, the authors discuss results from a qualitative research study involving the analysis of Personal Growth Project (PGP) assignments in a personal leadership education collegiate course. The…

A 1000 Arab genome project to study the Emirati population.

Science.gov (United States)

Al-Ali, Mariam; Osman, Wael; Tay, Guan K; AlSafar, Habiba S

2018-04-01

Discoveries from the human genome, HapMap, and 1000 genome projects have collectively contributed toward the creation of a catalog of human genetic variations that has improved our understanding of human diversity. Despite the collegial nature of many of these genome study consortiums, which has led to the cataloging of genetic variations of different ethnic groups from around the world, genome data on the Arab population remains overwhelmingly underrepresented. The National Arab Genome project in the United Arab Emirates (UAE) aims to address this deficiency by using Next Generation Sequencing (NGS) technology to provide data to improve our understanding of the Arab genome and catalog variants that are unique to the Arab population of the UAE. The project was conceived to shed light on the similarities and differences between the Arab genome and those of the other ethnic groups.

JOB DISCRIMINATION AGAINST WOMEN AND ENDOGENOUS POPULATION CHANGE IN A GENERALIZED SOLOW GROWTH MODEL

OpenAIRE

Wei-Bin ZHANG

2017-01-01

This study examines economic growth and population change with discrimination against women in the labor market within the analytical framework of Solow’s neoclassical growth model. The study models dynamic interactions between wealth accumulation, time distribution between work, children caring, and leisure, population change with endogenous birth and mortality rates with gender discrimination. The production technology and markets are built on Solow’s neoclassical growth model. The basic me...

Projections of the Population of the Republic of Croatia to the Year 2031: Can Migration Alleviate Future Negative Trends?

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Snježana Mrđen

2004-03-01

Full Text Available The paper presents middle duration projections of Croatia’s population, until the year 2031, determined via the cohort-component method. It outlines eight variants derived from supposed hypotheses in regard to changing birth, migration and death rates. Differences in the variants are exclusively differences in birth and migration rates, since the assumptions in regard to the death rates are the same in all the variants. The corrected estimate of the population on January 1st 2001, according to the most recent census, served as the base population. The results of the projections indicate that in the next thirty years the overall and the natural population reduction of Croatia will continue, and at the end of the period (2031 the population will be demographically older than at the start (2001. The variants differ only in relation to the intensity (i.e. swiftness of the aging process, yet the direction remains the same. Thus, in the variant that assumes a positive migration balance, the process of aging would be somewhat slower. The only variant that assumes a constant proportion of young people (on the 2001 level, gradual demographic growth and at the end of the period a larger population than in 2001, is the variant based on a high birth rate and positive migration. The impact of migration is very important for future demographic processes. Namely, in the short run, migration cannot change the direction of demographic processes, but it can lessen already existing negative trends.

Genomic growth curves of an outbred pig population

Directory of Open Access Journals (Sweden)

Fabyano Fonseca e Silva

2013-01-01

Full Text Available In the current post-genomic era, the genetic basis of pig growth can be understood by assessing SNP marker effects and genomic breeding values (GEBV based on estimates of these growth curve parameters as phenotypes. Although various statistical methods, such as random regression (RR-BLUP and Bayesian LASSO (BL, have been applied to genomic selection (GS, none of these has yet been used in a growth curve approach. In this work, we compared the accuracies of RR-BLUP and BL using empirical weight-age data from an outbred F2 (Brazilian Piau X commercial population. The phenotypes were determined by parameter estimates using a nonlinear logistic regression model and the halothane gene was considered as a marker for evaluating the assumptions of the GS methods in relation to the genetic variation explained by each locus. BL yielded more accurate values for all of the phenotypes evaluated and was used to estimate SNP effects and GEBV vectors. The latter allowed the construction of genomic growth curves, which showed substantial genetic discrimination among animals in the final growth phase. The SNP effect estimates allowed identification of the most relevant markers for each phenotype, the positions of which were coincident with reported QTL regions for growth traits.

Poverty, population growth, and youth violence in DRC's cities ...

International Development Research Centre (IDRC) Digital Library (Canada)

2016-04-28

Apr 28, 2016 ... Poverty, population growth, and youth violence in DRC's cities ... Learn more about what drives DRC's urban violence and how it is linked to poverty ... ​Youth violence and the shift of land disputes from rural communities into ...

525 Population Growth, Hysteresis and Development Outcomes in ...

African Journals Online (AJOL)

technique of analysis is the Auto-Regressive Distributed Lag (ARDL) Bound test for long-run ..... Where; y is the actual income; λ is the adjustment factor and gy is output per ... income per capita if population growth leaves the ratio of workers to total ..... 0.00 and 0.01 probability values are not normally distributed around the.

Population increase, economic growth, educational inequality, and income distribution: some recent evidence.

Science.gov (United States)

Ram, R

1984-04-01

The relationship between population increase, economic growth, education and income inequality was examined in a cross-section study based on data from 26 developing and 2 developed countries. As other studies have noted, high population growth is associated with a less equal income distribution. A 1 percentage point reduction in the rate of population growth tends to raise the income share of the poorest 80% in the less developed world by almost 5 percentage points and is associated with a 1.7 percentage point increase in the income share of the poorest 40%. The relationship between short-run income growth and equality, on the other hand, is strong and positive. Estimates suggest that a 1 percentage point increase in the short-run rate of growth of the gross domestic product (GDP) increases the income share of the bottom 80% by about 2 percentage points and that of the poorest 40% by almost 1 percentage point. Although higher mean schooling appears to be a mild equalizer, educational inequality does not appear to have an adverse effect on income distribution. Overall, these results challenge the widely held belief that there must be a growth-equity trade-off. Moreover, they suggest that the impact of educational inequality on income distribution may be different from that observed in earlier studies, implying a need for caution in using these earlier results as a basis for educational policy development.

Manual on Cost-Effectiveness of Training Modalities in Population Education. Population Education Programme Service Series.

Science.gov (United States)

United Nations Educational, Scientific and Cultural Organization, Bangkok (Thailand). Principal Regional Office for Asia and the Pacific.

This manual is the result of a regional training workshop on the cost-effectiveness of different training strategies in population education by Unesco in Kathmandu, Nepal, June 1-8, 1987. The purpose of the manual is to enable project staff to initiate studies to determine cost-effective training strategies in population growth control education.…

Strong persistent growth differences govern individual performance and population dynamics in a tropical forest understorey palm

NARCIS (Netherlands)

Jansen, M.; Zuidema, P.A.; Anten, N.P.R.; Martínez-Ramos, M.

2012-01-01

1. Persistent variation in growth rate between individual plants can have strong effects on population dynamics as fast growers reach the reproductive size at an earlier age and thus potentially contribute more to population growth than slow growers. In tropical forests, such persistent growth

Influence of Cell-Cell Interactions on the Population Growth Rate in a Tumor

Science.gov (United States)

Chen, Yong

2017-12-01

The understanding of the macroscopic phenomenological models of the population growth at a microscopic level is important to predict the population behaviors emerged from the interactions between the individuals. In this work, we consider the influence of the population growth rate R on the cell-cell interaction in a tumor system and show that, in most cases especially small proliferative probabilities, the regulative role of the interaction will be strengthened with the decline of the intrinsic proliferative probabilities. For the high replication rates of an individual and the cooperative interactions, the proliferative probability almost has no effect. We compute the dependences of R on the interactions between the cells under the approximation of the nearest neighbor in the rim of an avascular tumor. Our results are helpful to qualitatively understand the influence of the interactions between the individuals on the growth rate in population systems. Supported by the National Natural Science Foundation of China under Grant Nos. 11675008 and 21434001

The effects of declining population growth on the demand for housing.

Science.gov (United States)

Thomas C. Marcin

1974-01-01

Declining population growth and unprecedented changes in the age structure of the population in the next several decades will profoundly affect housing demand in the next 50 years. A decline in housing demand and substantial change in the type of housing in demand are likely to occur by 1990.

Population studies of echinoderms and growth and mortality of sea cucumbers

International Nuclear Information System (INIS)

Ebert, T.A.

1979-01-01

Progress is reported on the following studies: methods of collecting sea cucumbers; determination of growth rates of plates of the calcareous ring; use of growth parameters and a length-frequency distribution to estimate mortality and population turnover; movement of materials through the atoll ecosystem; and autoradiographic studies on spines of sea urchins

Growth in an English population from the Industrial Revolution.

Science.gov (United States)

Mays, S; Brickley, M; Ives, R

2008-05-01

The rapid urbanization of the Industrial Revolution in 18th-19th century England presented new health challenges. Our aim is to investigate using English skeletal remains whether the living conditions for an urban working class group in the Industrial Revolution negatively impacted upon their skeletal growth compared with a population from a rural agrarian parish. The Industrial Revolution skeletal material is from St Martin's Churchyard, Birmingham (SMB), West Midlands. It dates primarily from the first half of the nineteenth century when Birmingham was a major manufacturing center. The rural group is from Wharram Percy (WP), North Yorkshire, and dates from 10th-19th century AD. The methodology involves plotting diaphyseal bone lengths versus dental age for subadults. No overall difference was found between the two populations in bone length-for-age among the 2- to 18-year cohort. However the younger parts of the SMB cohort were smaller than at WP; the opposite was true of the older parts of the cohort. Growth rate, as inferred from crosssectional data, appeared greater at SMB than at WP. The only result consistent with expectations is the larger bone dimensions in young children from WP, but this likely reflects prolonged breastfeeding at WP not differences in urban and rural environments. That the deleterious health effects that we know accompanied the major transition in human society from a rural agrarian to an urban industrialized living environment should be little manifest in skeletal endochondral growth data is discouraging for those who would use such methodology to monitor health in earlier populations. (c) 2008 Wiley-Liss, Inc.

Projecting optimal land-use and -management strategies under population growth and climate change using a coupled ecosystem & land use model framework

Science.gov (United States)

Rabin, Sam; Alexander, Peter; Anthoni, Peter; Henry, Roslyn; Huntingford, Chris; Pugh, Thomas; Rounsevell, Mark; Arneth, Almut

2017-04-01

A major question facing humanity is how well agricultural production systems will be able to feed the world in a future of rapid climate change, population growth, and demand shifts—all while minimizing our impact on the natural world. Global modeling has frequently been used to investigate certain aspects of this question, but in order to properly address the challenge, no one part of the human-environmental system can be assessed in isolation. It is especially critical that the effect on agricultural yields of changing temperature and precipitation regimes (including seasonal timing and frequency and intensity of extreme events), as well as rising atmospheric carbon dioxide levels, be taken into account when planning for future food security. Coupled modeling efforts, where changes in various parts of the Earth system are allowed to feed back onto one another, represent a powerful strategy in this regard. This presentation describes the structure and initial results of an effort to couple a biologically-representative vegetation and crop production simulator, LPJ-GUESS, with the climate emulator IMOGEN and the land-use model PLUMv2. With IMOGEN providing detailed future weather simulations, LPJ-GUESS simulates natural vegetation as well as cropland and pasture/rangeland; the simulated exchange of greenhouse gases between the land and atmosphere feeds back into IMOGEN's predictions. LPJ-GUESS also produces potential vegetation yields for irrigated vs. rainfed crops under three levels of nitrogen fertilizer addition. PLUMv2 combines these potential yields with endogenous demand and agricultural commodity price to calculate an optimal set of land use distributions and management strategies across the world for the next five years of simulation, based on socio-economic scenario data. These land uses are then fed back into LPJ-GUESS, and the cycle of climate, greenhouse gas emissions, crop yields, and land-use change continues. The globally gridded nature of the

A necessary condition for dispersal driven growth of populations with discrete patch dynamics.

Science.gov (United States)

Guiver, Chris; Packman, David; Townley, Stuart

2017-07-07

We revisit the question of when can dispersal-induced coupling between discrete sink populations cause overall population growth? Such a phenomenon is called dispersal driven growth and provides a simple explanation of how dispersal can allow populations to persist across discrete, spatially heterogeneous, environments even when individual patches are adverse or unfavourable. For two classes of mathematical models, one linear and one non-linear, we provide necessary conditions for dispersal driven growth in terms of the non-existence of a common linear Lyapunov function, which we describe. Our approach draws heavily upon the underlying positive dynamical systems structure. Our results apply to both discrete- and continuous-time models. The theory is illustrated with examples and both biological and mathematical conclusions are drawn. Copyright © 2017 The Authors. Published by Elsevier Ltd.. All rights reserved.

The impact of population growth on environment: the debate heats up.

Science.gov (United States)

Shaw, R P

1992-02-01

A proposed framework, which was introduced at the 1989 meetings of the American Association for the Advancement of Science, included political constraints as well as population growth as a proximate cause with potentially important impacts on the environment in Paul and Ann Ehrlich's well-known PAT equation. PAT limitations are identified as the 1.2 billion people caught in the debt-poverty trap, less developed countries' balance of payments deficits, and "distortionary factors" that undermined economic incentives and contributed to mismanagement of resources. Such factors could be keeping farm prices low and have an impact on deterring use of environmentally sound traditional agricultural practices. Mismanagement of public lands occurs when large commercial enterprises or large scale mechanization displace population onto marginal or less productive lands. Intergroup warfare is a new form impacting on the environment. In Burma loggers are authorized to clear cut large tracts of teak forests in order to ferret out Karen guerrillas. Over 15 million refugees were thus displaced and forced to live in encampments that require trees for shelter, firewood for survival, and overgrazing of livestock. Social and economic environments are also undermined by "dependency" factors such as trade protectionism, brain drain, and limited foreign aid. The Group of 77 Non-Aligned Developing Countries proposed that discussions of the links between population and the environment be omitted from the agenda of the 1994 UN Conference on Population and Development. Basic clarifications are needed to distinguish ultimate versus proximate factors and current versus future concerns. The debate ignores distribution patterns, migration, or changing age structures. The debate blames unjustifiably rapid population growth as the ultimate cause of global environmental degradation and links population growth to a host of other social problems such as famine and refugees, while ignoring civil unrest

Rapid population growth and environmental degradation: ultimate versus proximate factors.

Science.gov (United States)

Shaw, R P

1989-01-01

This philosophical review of 2 arguments about responsibility for and solutions to environmental degradation concludes that both sides are correct: the ultimate and the proximal causes. Ultimate causes of pollution are defined as the technology responsible for a given type of pollution, such as burning fossil fuel; proximate causes are defined as situation-specific factors confounding the problem, such as population density or rate of growth. Commoner and others argue that developed countries with low or negative population growth rates are responsible for 80% of world pollution, primarily in polluting technologies such as automobiles, power generation, plastics, pesticides, toxic wastes, garbage, warfaring, and nuclear weapons wastes. Distortionary policies also contribute; examples are agricultural trade protection, land mismanagement, urban bias in expenditures, and institutional rigidity., Poor nations are responsible for very little pollution because poverty allows little waste or expenditures for polluting, synthetic technologies. The proximal causes of pollution include numbers and rate of growth of populations responsible for the pollution. Since change in the ultimate cause of pollution remains out of reach, altering the numbers of polluters can make a difference. Predictions are made for proportions of the world's total waste production, assuming current 1.6 tons/capita for developed countries and 0.17 tons/capita for developing countries. If developing countries grow at current rates and become more wealthy, they will be emitting half the world's waste by 2025. ON the other hand, unsustainable population growth goes along with inadequate investment in human capital: education, health, employment, infrastructure. The solution is to improve farming technologies in the 117 non-self-sufficient countries, fund development in the most unsustainable enclaves of growing countries, break institutionalized socio-political rigidity in these enclaves, and focus on

Genetic variation facilitates seedling establishment but not population growth rate of a perennial invader.

Science.gov (United States)

Li, Shou-Li; Vasemägi, Anti; Ramula, Satu

2016-01-01

Assessing the demographic consequences of genetic variation is fundamental to invasion biology. However, genetic and demographic approaches are rarely combined to explore the effects of genetic variation on invasive populations in natural environments. This study combined population genetics, demographic data and a greenhouse experiment to investigate the consequences of genetic variation for the population fitness of the perennial, invasive herb Lupinus polyphyllus. Genetic and demographic data were collected from 37 L. polyphyllus populations representing different latitudes in Finland, and genetic variation was characterized based on 13 microsatellite loci. Associations between genetic variation and population size, population density, latitude and habitat were investigated. Genetic variation was then explored in relation to four fitness components (establishment, survival, growth, fecundity) measured at the population level, and the long-term population growth rate (λ). For a subset of populations genetic variation was also examined in relation to the temporal variability of λ. A further assessment was made of the role of natural selection in the observed variation of certain fitness components among populations under greenhouse conditions. It was found that genetic variation correlated positively with population size, particularly at higher latitudes, and differed among habitat types. Average seedling establishment per population increased with genetic variation in the field, but not under greenhouse conditions. Quantitative genetic divergence (Q(ST)) based on seedling establishment in the greenhouse was smaller than allelic genetic divergence (F'(ST)), indicating that unifying selection has a prominent role in this fitness component. Genetic variation was not associated with average survival, growth or fecundity measured at the population level, λ or its variability. The study suggests that although genetic variation may facilitate plant invasions by

Analysis of Urban Growth in Edwardsville Illinois Using Remote Sensing and Population Change

Science.gov (United States)

Onuoha, Hilda U.

Rapid urbanization is one of the many critical, global issues. This very significant social and economic phenomenon has brought about much debate in the past twenty years and has become a very important policy issue. Understanding its dynamics and patterns is important to develop appropriate policies and make more informed planning decisions. Many dimensions to the urban land growth have been identified in related literature including drivers, relationship with other factors like population, impacts, and methods of measurement. In this study, urban growth in the Edwardsville area (composed of Edwardsville and Glen Carbon, Illinois) is analyzed spatio-temporally using remote sensing and population change from 1990 to 2015. The objectives of this study are (a) identifying the major land use changes in the Edwardsville area from 1990 to 2015, (b) analyzing the rate of urban growth and its relationship to population change in the area from 1990 to 2015, (c) identifying the general pattern and direction of urban growth in the study area. Using multi-temporal satellite images to classify and derive changes in land cover classes during the study period, results showed that the land cover classes with major changes are the urban/built-up land and agricultural/grassland, with a steady increase in the former and steady decrease in the later. Results also show the highest rate of increase in urban land was between 2000 and 2010. In comparison to population, the both show increase over the study years but urban land shows a higher rate of increase indicating dispersion. To analyze urban growth pattern in the area, the study area was divided into three zones: NE, SE, and W. The SE zone showed the highest amount of the growth and from the results, the infill type of growth was inferred.

Growth of the human lens in the Indian adult population: Preliminary observations

Directory of Open Access Journals (Sweden)

Ashik Mohamed

2012-01-01

Full Text Available Context: The eye lens grows throughout life by the addition of new cells inside the surrounding capsule. How this growth affects the properties of the lens is essential for understanding disorders such as cataract and presbyopia. Aims: To examine growth of the human lens in the Indian population and compare this with the growth in Western populations by measuring in vitro dimensions together with wet and dry weights. Settings and Design: The study was conducted at the research wing of a tertiary eye care center in South India and the study design was prospective. Materials and Methods: Lenses were removed from eye bank eyes and their dimensions measured with a digital caliper. They were then carefully blotted dry and weighed before being placed in 5% buffered formalin. After 1 week fixation, the lenses were dried at 80 °C until constant weight was achieved. The constant weight was noted as the dry weight of the lens. Statistical Analysis Used: Lens parameters were analyzed as a function of age using linear and logarithmic regression methods. Results: Data were obtained for 251 lenses, aged 16-93 years, within a median postmortem time of 22 h. Both wet and dry weights increased linearly at 1.24 and 0.44 mg/year, respectively, throughout adult life. The dimensions also increased continuously throughout this time. Conclusions: Over the age range examined, lens growth in the Indian population is very similar to that in Western populations.

Rapid Population Growth and Human Carrying Capacity: Two Perspectives. World Bank Staff Working Papers No. 690 and Population and Development Series No. 15.

Science.gov (United States)

Mahar, Dennis J., Ed.; And Others

Two perspectives on carrying capacity and population growth are examined. The first perspective, "Carrying Capacity and Rapid Population Growth: Definition, Cases, and Consequences" (Robert Muscat), explores the possible meanings of the idea of carrying capacity under developing country conditions, looks at historical and present-day cases of…

Project ZEUS: a field irradiator for small-mammal population studies

International Nuclear Information System (INIS)

Turner, B.N.; Iverson, S.L.

1976-08-01

The ZEUS (Zoological Environment Under Stress) Project will assess the effects of long-term low-level radiation on meadow vole populations in a northern temperate area through a series of replicated experimental irradiations. These rodent populations will live in grassland areas surrounded by forest, and will be exposed to a dose designed to be a maximum 6 R/day. (author)

Studies of Health and Long-Term Care Expenditure Growth in Aging Populations

NARCIS (Netherlands)

C.A.M. de Meijer (Claudine)

2012-01-01

textabstractIn recent decades, elderly populations in most developed countries have increased considerably, both in absolute and relative terms. This growth of the elderly share of the population is mainly attributable to two demographic transitions: the (simultaneous) increase in longevity and

"Peer Review: Nonroad (NR) Updates to Population Growth, Compression Ignition (CI) Criteria, Toxic Emission Factors and Speciation Profiles"

Science.gov (United States)

This report focuses on the methodology for estimating growth in NR engine populations as used in the MOVES201X-NONROAD emission inventory model. MOVES NR growth rates start with base year engine populations and estimate growth in the populations of NR engines, while applying cons...

The demographic consequences of mutualism: ants increase host-plant fruit production but not population growth

Science.gov (United States)

Kevin Ford; Joshua H. Ness; Judith L. Bronstein; William F. Morris

2015-01-01

The impact of mutualists on a partner’s demography depends on how they affect the partner’s multiple vital rates and how those vital rates, in turn, affect population growth. However, mutualism studies rarely measure effects on multiple vital rates or integrate them to assess the ultimate impact on population growth. We used vital rate data, population models and...

Population growth and United States politics in the 1970s.

Science.gov (United States)

Nash, A E

1973-01-01

The 2 themes of this century, increasing environmental fragility and increasing human demands on government, are underlined by the failure of government to effectively govern, and the complex technology and modern communication systems which further divide the developing nations from the developed ones. Population stabilization may help relieve the tension between increasing expectation from government and the fiscal bind in 3 ways: 1)a higher per capita income would increase per capita government revenue which would have a better chance of meeting citizen expectations, 2)a moderately redistributive effect on personal income might occur by decreasing unwanted fertility through the dynamics of economics and increasing the role of government in elevating living standards, and 3)with reduction of government expenditure per capita, the cost of providing any given level of service would decrease. The nuclear age has altered the concept of what constitutes national security. Rapid population growth in the developing countries is also significant, and the United States economy depends on overseas investment. A constructive foreign policy, as opposed to neoimperialism or isolationism, is recommended to help influence world population growth.

Postnatal growth standards for preterm infants: the Preterm Postnatal Follow-up Study of the INTERGROWTH-21(st) Project.

Science.gov (United States)

Villar, José; Giuliani, Francesca; Bhutta, Zulfiqar A; Bertino, Enrico; Ohuma, Eric O; Ismail, Leila Cheikh; Barros, Fernando C; Altman, Douglas G; Victora, Cesar; Noble, Julia A; Gravett, Michael G; Purwar, Manorama; Pang, Ruyan; Lambert, Ann; Papageorghiou, Aris T; Ochieng, Roseline; Jaffer, Yasmin A; Kennedy, Stephen H

2015-11-01

Charts of size at birth are used to assess the postnatal growth of preterm babies on the assumption that extrauterine growth should mimic that in the uterus. The INTERGROWTH-21(st) Project assessed fetal, newborn, and postnatal growth in eight geographically defined populations, in which maternal health care and nutritional needs were met. From these populations, the Fetal Growth Longitudinal Study selected low-risk women starting antenatal care before 14 weeks' gestation and monitored fetal growth by ultrasonography. All preterm births from this cohort were eligible for the Preterm Postnatal Follow-up Study, which included standardised anthropometric measurements, feeding practices based on breastfeeding, and data on morbidity, treatments, and development. To construct the preterm postnatal growth standards, we selected all live singletons born between 26 and before 37 weeks' gestation without congenital malformations, fetal growth restriction, or severe postnatal morbidity. We did analyses with second-degree fractional polynomial regression models in a multilevel framework accounting for repeated measures. Fetal and neonatal data were pooled from study sites and stratified by postmenstrual age. For neonates, boys and girls were assessed separately. From 4607 women enrolled in the study, there were 224 preterm singleton births, of which 201 (90%) were enrolled in the Preterm Postnatal Follow-up Study. Variance component analysis showed that only 0·2% and 4·0% of the total variability in postnatal length and head circumference, respectively, could be attributed to between-site differences, justifying pooling the data from all study sites. Preterm growth patterns differed from those for babies in the INTERGROWTH-21(st) Newborn Size Standards. They overlapped with the WHO Child Growth Standards for term babies by 64 weeks' postmenstrual age. Our data have yielded standards for postnatal growth in preterm infants. These standards should be used for the assessment of

Comparisons of Growth and Survival Performance Among Selected Families and Wild Populations of Fenneropenaeus chinensis

Science.gov (United States)

Luo, Kun; Kong, Jie; Meng, Xianhong; Luan, Sheng; Cao, Baoxiang; Chen, Baolong

2018-04-01

In this study, families of selected population for growth (SP_BWT), selected population for white spot syndrome virus (WSSV) resistance (SP_RW), Bohai wild population (WP_BH) and Huanghai wild population (WP_HH) of F. chinensis were constructed through artificial insemination and with the standardized procedure of larvae rearing. Growth and survival performance were studied among four populations after a 70 days common test. The results showed that the maximum least square mean of body weight was 17.50 g in SP_BWT while the minimum was 13.03 g in WP_HH. Compared with WP_BH, body weight of SP_BWT increased by 23.41% ( P 0.05). Body weights of SP_BWT and SP_RW were significantly higher than that of WP_HH, which increased by 34.31% ( P populations was 0.19, 0.18, 0.17 and 0.16 g d-1, respectively. Coefficient of variation of body weight among four populations was high, which ranged from 32.67% to 35.25%. Such a range showed that there was the potentiality for further improvement in selected populations. Coefficient of variation of survival rate among four populations was low, varying between 3.20% and 5.90%. The difference of survival was highly significant ( P populations ( P growth performances were also observed among different families in each population. The body weight of 798F family was the highest. The absolute growth rate (AGR) was 0.25 g d-1, 150% higher than that of the lowest one, 0.1 g d-1 in 807F family. Survival rate of families among four populations was different. The highest was 94.74%, and the lowest was 71.88%.

Population prospects for Sub-Saharan Africa: determinants, consequences and policy.

Science.gov (United States)

Huth, M J

1986-01-01

Population projections for nine Sub-Saharan African countries (excluding southern Africa) are reviewed for the period to the year 2020. Consideration is given to the determinants of fertility and to the consequences of rapid population growth. Suggestions for population policies that will resolve population-related development problems are discussed.

A new ODE tumor growth modeling based on tumor population dynamics

Energy Technology Data Exchange (ETDEWEB)

Oroji, Amin; Omar, Mohd bin [Institute of Mathematical Sciences, Faculty of Science University of Malaya, 50603 Kuala Lumpur, Malaysia amin.oroji@siswa.um.edu.my, mohd@um.edu.my (Malaysia); Yarahmadian, Shantia [Mathematics Department Mississippi State University, USA Syarahmadian@math.msstate.edu (United States)

2015-10-22

In this paper a new mathematical model for the population of tumor growth treated by radiation is proposed. The cells dynamics population in each state and the dynamics of whole tumor population are studied. Furthermore, a new definition of tumor lifespan is presented. Finally, the effects of two main parameters, treatment parameter (q), and repair mechanism parameter (r) on tumor lifespan are probed, and it is showed that the change in treatment parameter (q) highly affects the tumor lifespan.

A new ODE tumor growth modeling based on tumor population dynamics

International Nuclear Information System (INIS)

Oroji, Amin; Omar, Mohd bin; Yarahmadian, Shantia

2015-01-01

In this paper a new mathematical model for the population of tumor growth treated by radiation is proposed. The cells dynamics population in each state and the dynamics of whole tumor population are studied. Furthermore, a new definition of tumor lifespan is presented. Finally, the effects of two main parameters, treatment parameter (q), and repair mechanism parameter (r) on tumor lifespan are probed, and it is showed that the change in treatment parameter (q) highly affects the tumor lifespan

Effects of Helicobacter pylori infection and smoking on gastric cancer incidence in China: a population-level analysis of trends and projections

Science.gov (United States)

Goldie, Sue J.; Kuntz, Karen M.; Ezzati, Majid

2010-01-01

Objective Although gastric cancer incidence is declining in China, trends may differ from historical patterns in developed countries. Our aim was to (1) retrospectively estimate the effects of Helicobacter pylori (H. pylori) and smoking on past gastric cancer incidence and (2) project how interventions on these two risk factors can reduce future incidence. Methods We used a population-based model of intestinal-type gastric cancer to estimate gastric cancer incidence between 1985 and 2050. Disease and risk factor data in the model were from community-based epidemiological studies and national prevalence surveys. Results Between 1985 and 2005, age-standardized gastric cancer incidence among Chinese men declined from 30.8 to 27.2 per 100,000 (12%); trends in H. pylori and smoking prevalences accounted for >30% of overall decline. If past risk factor trends continue, gastric cancer incidence will decline an additional 30% by 2050. Yet, annual cases will increase from 116,000 to 201,000 due to population growth and aging. Assuming that H. pylori prevention/treatment and tobacco control are implemented in 2010, the decline in gastric cancer incidence is projected to increase to 33% with universal H. pylori treatment for 20-year-olds, 42% for a hypothetical childhood H. pylori vaccine, and 34% for aggressive tobacco control. Conclusions The decline in gastric cancer incidence has been slower than in developed countries and will be offset by population growth and aging. Public health interventions should be implemented to reduce the total number of cases. PMID:19642005

Nonlinear dynamics in a business-cycle model with logistic population growth

International Nuclear Information System (INIS)

Brianzoni, Serena; Mammana, Cristiana; Michetti, Elisabetta

2009-01-01

We consider a discrete-time growth model of the Solow type where workers and shareholders have different but constant saving rates and the population growth dynamics is described by the logistic equation able to exhibit complicated dynamics. We show conditions for the resulting system having a compact global attractor and we describe its structure. We also perform a mainly numerical analysis using the critical lines method able to describe the strange attractor and the absorbing area, in order to show how cyclical or complex fluctuations may be produced in a business-cycle model. We study the dynamic behaviour of the model under different ranges of the main parameters, i.e. the elasticity of substitution between the two production factors and the one in the logistic equation (namely μ). We prove the existence of complex dynamics when the elasticity of substitution between production factors drops below one (so that capital income declines) or μ increases (so that the amplitude of movements in the population growth rate increases).

Population parameters for dose calculations: initial estimates of municipal, city and provincial age group population within 20, 50 and 80 kilometers of the PNPP-1

International Nuclear Information System (INIS)

Ramirez, R.A.

1985-01-01

The study attempts to determine the total population and population growth rates of four (4) age groups per municipality/city within twenty (20), fifty (50) and eighty (80) kilometers from the Philippine Nuclear Power Plant (PNPP-1). The population estimates were done at five (5) year intervals covering the next fifty years. The latest National Census and Statistics Office (NCSO) population projections at the provincial level under the assumption of moderate fertility and moderate mentality decline (series no. 2) were used to derive the estimates of the total population and population growth rates at the minicipality/city levels. The Bureau of Coastal and Geodetic Survey (BCGS) and the NCSO maps served as the bases for delineating the geographic and political boundaries covered by the study. The results will complement the findings of the PAEC project on agricultural parameters for radiation dose calculations and useful for related environmental studies. (author)

Fetal growth and risk of stillbirth: a population-based case-control study.

Science.gov (United States)

Bukowski, Radek; Hansen, Nellie I; Willinger, Marian; Reddy, Uma M; Parker, Corette B; Pinar, Halit; Silver, Robert M; Dudley, Donald J; Stoll, Barbara J; Saade, George R; Koch, Matthew A; Rowland Hogue, Carol J; Varner, Michael W; Conway, Deborah L; Coustan, Donald; Goldenberg, Robert L

2014-04-01

Stillbirth is strongly related to impaired fetal growth. However, the relationship between fetal growth and stillbirth is difficult to determine because of uncertainty in the timing of death and confounding characteristics affecting normal fetal growth. We conducted a population-based case-control study of all stillbirths and a representative sample of live births in 59 hospitals in five geographic areas in the US. Fetal growth abnormalities were categorized as small for gestational age (SGA) (90th percentile) at death (stillbirth) or delivery (live birth) using population, ultrasound, and individualized norms. Gestational age at death was determined using an algorithm that considered the time-of-death interval, postmortem examination, and reliability of the gestational age estimate. Data were weighted to account for the sampling design and differential participation rates in various subgroups. Among 527 singleton stillbirths and 1,821 singleton live births studied, stillbirth was associated with SGA based on population, ultrasound, and individualized norms (odds ratio [OR] [95% CI]: 3.0 [2.2 to 4.0]; 4.7 [3.7 to 5.9]; 4.6 [3.6 to 5.9], respectively). LGA was also associated with increased risk of stillbirth using ultrasound and individualized norms (OR [95% CI]: 3.5 [2.4 to 5.0]; 2.3 [1.7 to 3.1], respectively), but not population norms (OR [95% CI]: 0.6 [0.4 to 1.0]). The associations were stronger with more severe SGA and LGA (95th percentile). Analyses adjusted for stillbirth risk factors, subset analyses excluding potential confounders, and analyses in preterm and term pregnancies showed similar patterns of association. In this study 70% of cases and 63% of controls agreed to participate. Analysis weights accounted for differences between consenting and non-consenting women. Some of the characteristics used for individualized fetal growth estimates were missing and were replaced with reference values. However, a sensitivity analysis using individualized norms

Social Security Reform and Population Ageing in a Two-Sector Growth Model

NARCIS (Netherlands)

van Groezen, B.J.A.M.; Meijdam, A.C.; Verbon, H.A.A.

2002-01-01

This paper analyses the effects of reducing unfunded social security and population ageing on economic growth and welfare, both for a small open economy and for a closed economy.The economy consists of a service sector and a commodity sector.Productivity growth only occurs in the latter sector and

JOB DISCRIMINATION AGAINST WOMEN AND ENDOGENOUS POPULATION CHANGE IN A GENERALIZED SOLOW GROWTH MODEL

Directory of Open Access Journals (Sweden)

Wei-Bin ZHANG

2017-06-01

Full Text Available This study examines economic growth and population change with discrimination against women in the labor market within the analytical framework of Solow’s neoclassical growth model. The study models dynamic interactions between wealth accumulation, time distribution between work, children caring, and leisure, population change with endogenous birth and mortality rates with gender discrimination. The production technology and markets are built on Solow’s neoclassical growth model. The basic mechanisms for population changes in the Barro-Becker fertility choice model and the Haavelmo population model are integrated to model the population change. This study also takes account of discrimination against woman in the labor market. We synthesize these dynamic forces in a compact framework by applying Zhang’s utility function. The model properties are studied by simulation. We find equilibrium points and illustrate motion of the dynamic system. We also examine the effects of changes in the discrimination against woman, the propensity to save, woman’s propensity to pursue leisure activities, the propensity to have children, woman’s human capital and man’s emotional involvement in children caring.

Population size structure indices and growth standards for Salmo (trutta trutta Linnaeus, 1758 in Central Italy

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Pedicillo G.

2010-10-01

Full Text Available The purpose of this study was to provide reference data on the growth and population structure of brown trout Salmo (trutta trutta Linnaeus, in Central Italy. Standards for growth (percentiles and a standard growth model were developed from the von Bertalanffy growth model by using length-at-age data obtained from 122 sampling sites in the River Tiber basin. Length-frequency indices provide a numeric estimation for deviations of the population structure from a balanced population. We adapted the traditional North American Relative Stock Density (RSD and Proportional Stock Density (PSD indices to brown trout populations in Central Italy by means of two methods. In the first method, the benchmarks of length categories were established by using percentages applied to the largest individual in the dataset. In the second method, asymptotic length and size at maturity were used to define the length categories for index calculation. Both methods were tested on length-frequency data from 263 sampling sites in the River Tiber basin. The results showed that the PSD calculated by the first method provided a better insight into the population structures of brown trout. These results provide tools that will help ichthyologists and fish managers to compare the growth and population structure of brown trout throughout Central Italy.

Population growth and development of Liposcelis pearmani (Psocoptera: Liposcelididae) at constant temperatures and relative humidities.

Science.gov (United States)

Aminatou, B A; Gautam, S G; Opit, G P; Talley, J; Shakya, K

2011-08-01

Psocids of genus Liposcelis are now considered serious pests of stored products. We investigated the effects of eight temperatures (22.5, 25.0, 27.5, 30.0, 32.5, 35.0, 37.5, and 40.0°C) and four relative humidities (43, 55, 63, and 75%) on population growth and development of the psocid Liposcelis pearmani Lienhard. L. pearmani did not survive at 37.5 and 40.0°C, at all relative humidities tested; at 43% RH, at all temperatures tested; and at 55% RH, at 32.5 and 35°C. The greatest population growth was recorded at 32.5°C and 75% RH (32-fold growth). L. pearmani males have two to four nymphal instars, and the percentages of males with two, three, and four instars were 17, 63, and 20%, respectively. Female L. pearmani have two to five instars, and the percentages of females with two, three, four, and five instars were 5, 39, 55, and 1%, respectively. We developed temperature-dependent development equations for male and female eggs, individual nymphal, combined nymphal, and combined immature stages. Based on 30-d population growth, L. pearmani cannot survive at temperatures >35.0°C; does not thrive at low relative humidities (55%), at temperatures above 25°C; and has a high optimum relative humidity for population growth (75%). Therefore, we expect it to have a more limited distribution compared with other Liposcelis species. These data provide a better understanding of how temperature and RH may influence L. pearmani population dynamics and can be used in population growth models to help develop effective management strategies for this psocid, and to predict its occurrence.

Dynamics of urban population growth in Nigeria: The role of repeated migration.

Science.gov (United States)

Adepoju, A

1976-02-01

The paper examines the direct contribution of migration to the growth of the urban population both in terms of its mobility and stability components with special reference to Western Nigeria. The basis of the paper is a survey of urban migration conducted by the author in 1971-1972; the findings are supplemented where necessary by the 1952-1953 and 1963 census figures. Migration is a major factor in the growth of the urban population. The direct contribution by migrants to such growth can be traced to the following groups: the initial streams of migrants, the follow-up migrants and the potentially mobile migrants attracted from the migrants' communities of origin to the towns. Repeated migration by some migrants, particularly the young, the educated and the white collar-workers, are also major factors in the urban population growth. Such repeated migrations are predominantly urban to urban or turnover moves. The high mobility rate among a group of migrants tends to conceal the relative stability among the migrant population as a whole. Repeated migrants usually stay between 3 and 5 years at each destination, before moving on. A substantial proportion of migrants, mainly farmers, the less educated and the old, are relatively stable in the survey towns (Ife and Oshogho). The urban residence ration indices also indicate an increase in the rate of immigration, mainly of young persons, to the towns. The youthful age structure, the age selectivity in migration and the marital status of the young migrants tend to exacerbate the masculinity in the form of unbalanced sex ratio prevailing in most urban centers. The urban population is unlikely to be stable. The tendency for old migrants of rural origin to return to their villages at the end of their migration career and for contemporary migrants to consist predominantly of youths, will for the next generation or 2 lead to a young and unstable urban population.

[Effect of the population density on growth and regeneration in the snail Achatina fulica].

Science.gov (United States)

Sidel'nikov, A P; Stepanov, I I

2000-01-01

In the laboratory, the growth rate of the giant African snail Achatina fulica, as estimated by the weight and shell length was shown to decrease when the population density increased from 10 to 60 snails/m2 of the total terrarium area for five months. In the second experiment, when the population density increased from 48 to 193 snails/m2, the growth rate had already decreased by six weeks. In the groups with a high population density the feeding behavior was weakened, expressed by a greater amount of nonconsumed food, according to visual observations, than in the groups with lower population densities. At the population density of 10 to 60 snails/m2, the proliferative activity in the course of the optic tentacle regeneration, as expressed by the mitotic index, did not differ reliably within five months. In the second experiment, the mitotic indices at the population densities of 96 and 193 snails/m2 within 1.5 months exceeded that of 48 snails/m2. Recommendations are given concerning the population density from the viewpoint of commercial growth of the snails. It was proposed that, based on the analysis of the mechanism underlying the inhibition of feeding behavior in populations with extra high densities, one may develop a new approach to the production of chemical agents to control land snails as agricultural pests.

Growth rates and variances of unexploited wolf populations in dynamic equilibria

Science.gov (United States)

Mech, L. David; Fieberg, John

2015-01-01

Several states have begun harvesting gray wolves (Canis lupus), and these states and various European countries are closely monitoring their wolf populations. To provide appropriate perspective for determining unusual or extreme fluctuations in their managed wolf populations, we analyzed natural, long-term, wolf-population-density trajectories totaling 130 years of data from 3 areas: Isle Royale National Park in Lake Superior, Michigan, USA; the east-central Superior National Forest in northeastern Minnesota, USA; and Denali National Park, Alaska, USA. Ratios between minimum and maximum annual sizes for 2 mainland populations (n = 28 and 46 yr) varied from 2.5–2.8, whereas for Isle Royale (n = 56 yr), the ratio was 6.3. The interquartile range (25th percentile, 75th percentile) for annual growth rates, Nt+1/Nt, was (0.88, 1.14), (0.92, 1.11), and (0.86, 1.12) for Denali, Superior National Forest, and Isle Royale respectively. We fit a density-independent model and a Ricker model to each time series, and in both cases we considered the potential for observation error. Mean growth rates from the density-independent model were close to 0 for all 3 populations, with 95% credible intervals including 0. We view the estimated model parameters, including those describing annual variability or process variance, as providing useful summaries of the trajectories of these populations. The estimates of these natural wolf population parameters can serve as benchmarks for comparison with those of recovering wolf populations. Because our study populations were all from circumscribed areas, fluctuations in them represent fluctuations in densities (i.e., changes in numbers are not confounded by changes in occupied area as would be the case with populations expanding their range, as are wolf populations in many states).

Social security reform and population ageing in a two-sector growth model

NARCIS (Netherlands)

Groezen, Bas van; Meijdam, L.; Verbon, H.

2002-01-01

This paper analyses the e¤ects of reducing unfunded social security and population ageing on economic growth and welfare, both for a small open economy and for a closed economy. The economy consists of a service sector and a commodity sector. Productivity growth only occurs in the latter sector

Populational Growth Models Proportional to Beta Densities with Allee Effect

Science.gov (United States)

Aleixo, Sandra M.; Rocha, J. Leonel; Pestana, Dinis D.

2009-05-01

We consider populations growth models with Allee effect, proportional to beta densities with shape parameters p and 2, where the dynamical complexity is related with the Malthusian parameter r. For p>2, these models exhibit a population dynamics with natural Allee effect. However, in the case of 1

Density regulation in Northeast Atlantic fish populations: Density dependence is stronger in recruitment than in somatic growth.

Science.gov (United States)

Zimmermann, Fabian; Ricard, Daniel; Heino, Mikko

2018-05-01

Population regulation is a central concept in ecology, yet in many cases its presence and the underlying mechanisms are difficult to demonstrate. The current paradigm maintains that marine fish populations are predominantly regulated by density-dependent recruitment. While it is known that density-dependent somatic growth can be present too, its general importance remains unknown and most practical applications neglect it. This study aimed to close this gap by for the first time quantifying and comparing density dependence in growth and recruitment over a large set of fish populations. We fitted density-dependent models to time-series data on population size, recruitment and age-specific weight from commercially exploited fish populations in the Northeast Atlantic Ocean and the Baltic Sea. Data were standardized to enable a direct comparison within and among populations, and estimated parameters were used to quantify the impact of density regulation on population biomass. Statistically significant density dependence in recruitment was detected in a large proportion of populations (70%), whereas for density dependence in somatic growth the prevalence of density dependence depended heavily on the method (26% and 69%). Despite age-dependent variability, the density dependence in recruitment was consistently stronger among age groups and between alternative approaches that use weight-at-age or weight increments to assess growth. Estimates of density-dependent reduction in biomass underlined these results: 97% of populations with statistically significant parameters for growth and recruitment showed a larger impact of density-dependent recruitment on population biomass. The results reaffirm the importance of density-dependent recruitment in marine fishes, yet they also show that density dependence in somatic growth is not uncommon. Furthermore, the results are important from an applied perspective because density dependence in somatic growth affects productivity and

The Association between Natural Amenities, Rural Population Growth, and Long-Term Residents' Economic Well-Being

Science.gov (United States)

Hunter, Lori M; Boardman, Jason D.; Saint Onge, Jarron M.

2005-01-01

Population growth in rural areas characterized by high levels of natural amenities has recently received substantial research attention. A noted concern with amenity-driven rural population growth is its potential to raise local costs-of-living while yielding only low-wage service sector employment for long-term residents. The work presented here…

Demographic Models for Projecting Population and Migration: Methods for African Historical Analysis

Directory of Open Access Journals (Sweden)

Patrick Manning

2015-08-01

Full Text Available This study presents methods for projecting population and migration over time in cases were empirical data are missing or undependable. The methods are useful for cases in which the researcher has details of population size and structure for a limited period of time (most obviously, the end point, with scattered evidence on other times. It enables estimation of population size, including its structure in age, sex, and status, either forward or backward in time. The program keeps track of all the details. The calculated data can be reported or sampled and compared to empirical findings at various times and places to expected values based on other procedures of estimation. The application of these general methods that is developed here is the projection of African populations backwards in time from 1950, since 1950 is the first date for which consistently strong demographic estimates are available for national-level populations all over the African continent. The models give particular attention to migration through enslavement, which was highly important in Africa from 1650 to 1900. Details include a sensitivity analysis showing relative significance of input variables and techniques for calibrating various dimensions of the projection with each other. These same methods may be applicable to quite different historical situations, as long as the data conform in structure to those considered here.

The Vatican & Population Growth Control: Why an American Confrontation?

Science.gov (United States)

Mumford, Stephen D.

1983-01-01

The Vatican, because of its position on population growth, threatens the security of all nations. Catholic countries with right-wing dictatorships cannot confront the Vatican on family planning and survive. U.S. Catholics must confront the Vatican on this issue. American lay Catholics must break the American church away from the Vatican control.…

Linking individual phenotype to density-dependent population growth: the influence of body size on the population dynamics of malaria vectors

NARCIS (Netherlands)

Russell, T.L.; Lwetoijera, D.W.; Knols, B.G.J.; Takken, W.; Killeen, G.F.; Ferguson, H.M.

2011-01-01

Understanding the endogenous factors that drive the population dynamics of malaria mosquitoes will facilitate more accurate predictions about vector control effectiveness and our ability to destabilize the growth of either low- or high-density insect populations. We assessed whether variation in

Linking individual phenotype to density-dependent population growth: the influence of body size on the population dynamics of malaria vectors

NARCIS (Netherlands)

Russell, T.L.; Lwetoijera, D.W.; Knols, B.G.J.; Takken, W.; Killeen, G.F.; Ferguson, H.M.

2011-01-01

Understanding the endogenous factors that drive the population dynamics of malaria mosquitoes will facilitate more accurate predictions about vector control effectiveness and our ability to destabilize the growth of either low-or high-density insect populations. We assessed whether variation in

[Population trends and poverty].

Science.gov (United States)

Olmedo, C

1998-04-01

Implications of population growth in Ecuador for the quality of life of the poor population are analyzed. It is argued that if the gross national product (GNP) were to grow at a sustained annual rate of 5% or more, demographic trends would not present a significant obstacle to reducing poverty. National economic projections are for growth of only 2.5-3.5% annually. The continuing rapid growth of the poor population despite general slowing of demographic growth, the young age structure, the need for increased formal education to enable the poor to overcome their poverty, and the effect of unemployment on the dependency ratio will tend to hamper improvements in average productivity and per capita GNP. The need for spending on education, health, basic services, and housing will divert funds away from productive investment, generating a direct negative impact on economic growth. Over half of Ecuadorian children suffer from some degree of malnutrition, indicating that food production is inadequate to meet demand. The export-oriented agricultural policy and poor weather have led to a chronic shortage of basic foods. Progressive increase and diversification of agricultural production, along with maintenance of low prices and substantial increases in income levels and agricultural productivity, will be required if the entire population is to be fed adequately. Intense efforts will be needed from all sectors to bring demographic growth into balance with economic and development needs.

Population growth rate and genetic variability of small and large populations of Red flour beetle (Tribolium castaneum) following multigenerational exposure to copper.

Science.gov (United States)

Laskowski, Ryszard; Radwan, Jacek; Kuduk, Katarzyna; Mendrok, Magdalena; Kramarz, Paulina

2015-07-01

We reared large (1000 individuals) and small (20 individuals) populations of Tribolium castaneum on diet contaminated with copper in order to determine if the size of a population affects its ability to adapt to adverse environmental conditions. After 10 generations, we used microsatellite markers to estimate and subsequently compare the genetic variability of the copper-treated populations with that of the control populations, which were reared on uncontaminated medium. Additionally, we conducted a full cross-factorial experiment which evaluated the effects of 10 generations of "pre-exposure" to copper on a population's fitness in control and copper-contaminated environments. In order to distinguish results potentially arising from genetic adaptation from those due to non-genetic effects associated to parental exposure to copper, we subjected also F11 generation, originating from parents not exposed to copper, to the same cross-factorial experiment. The effects of long-term exposure to copper depended on population size: the growth rates of small populations that were pre-exposed to copper were inhibited compared to those of small populations reared in uncontaminated environments. Large Cu-exposed populations had a higher growth rate in the F10 generation compared to the control groups, while the growth rate of the F11 generation was unaffected by copper exposure history. The only factor that had a significant effect on genetic variability was population size, but this was to be expected given the large difference in the number of individuals between large and small populations. Neither copper contamination nor its interaction with population size affected the number of microsatellite alleles retained in the F10 generation.

Is Demography Destiny? Urban Population Change and Economic Vitality of Future Cities

Directory of Open Access Journals (Sweden)

Jacques Poot

Full Text Available ABSTRACT: The growth of cities has attracted considerable scholarly attention during the last decade as it is becoming clear that powerful agglomeration forces are reinforcing the role of cities as the engines of economic growth. Close to 4 billion people live in cities, about 55 per cent of the world's population. While population growth rates are declining and the world's population is likely to level off from the middle of the 21st century, probably ending up around 10 billion, further urbanization is expected to continue. Another 3 billion people will become urban citizens this century. At the same time no corner of the world will be sheltered from sweeping demographic changes due to population ageing and increasing migration. Such changes will be amplified in cities. In this paper we combine UN population projections and migration data with our own assumptions to derive projections of age composition and birthplace composition of urban populations by continent. We also briefly address the consequences of these demographic trends for future urban economic vitality. Particular attention is paid to the impacts of demographic changes on urban creativity and innovation. We conclude that, with the right policies in place, such demographic changes enhance rather than impede the future prosperity of the urban world. KEYWORDS: World population projections, urbanization, ageing, migration, ethnic diversity

Anthropometric growth study of the ear in a Chinese population.

Science.gov (United States)

Zhao, Shichun; Li, Dianguo; Liu, Zhenzhong; Wang, Yibiao; Liu, Lei; Jiang, Duyin; Pan, Bo

2018-04-01

A large number of anthropometric studies of the auricle have been reported in different nations, but little data were available in the Chinese population. The aim of this study was to analyze growth changes in the ear by measuring the width and length of ears in a Chinese population. A total of 480 participants were enrolled and classified into 1-, 3-, 5-, 7-, 9-, 12-, 14-, and 18-year groups (half were boys and half were girls in each group). Ear length, ear width, body weight, and body length were measured and recorded; ear index was calculated according to ear length and ear width. The growth of auricle and differences between genders were analyzed. Growth of ear in relation to body height and weight and the degree of emphasis on the length and width of the auricle were also analyzed. Ear length and width increased with age. Ear length achieved its mature size in both 14-year-old males and females. Ear width reached its mature size in males at 7 years and in females at 5 years. Different trends of ear index were shown between males and females. People in this population paid more attention to the length than the width of the auricle. The data indicated that ear development followed increase in age. There were gender and ethnic difference in the development of ear. These results may have potential implications for the diagnosis of congenital malformations, syndromes, and planning of ear reconstruction surgery. Copyright © 2017 British Association of Plastic, Reconstructive and Aesthetic Surgeons. Published by Elsevier Ltd. All rights reserved.

Detecting crop population growth using chlorophyll fluorescence imaging.

Science.gov (United States)

Wang, Heng; Qian, Xiangjie; Zhang, Lan; Xu, Sailong; Li, Haifeng; Xia, Xiaojian; Dai, Liankui; Xu, Liang; Yu, Jingquan; Liu, Xu

2017-12-10

For both field and greenhouse crops, it is challenging to evaluate their growth information on a large area over a long time. In this work, we developed a chlorophyll fluorescence imaging-based system for crop population growth information detection. Modular design was used to make the system provide high-intensity uniform illumination. This system can perform modulated chlorophyll fluorescence induction kinetics measurement and chlorophyll fluorescence parameter imaging over a large area of up to 45  cm×34  cm. The system can provide different lighting intensity by modulating the duty cycle of its control signal. Results of continuous monitoring of cucumbers in nitrogen deficiency show the system can reduce the judge error of crop physiological status and improve monitoring efficiency. Meanwhile, the system is promising in high throughput application scenarios.

Assessment of knowledge and skills about growth monitoring amongst multipurpose workers in an ICDS project.

Science.gov (United States)

Kapil, U; Sood, A K; Gaur, D R; Bhasin, S

1991-08-01

Knowledge and skills amongst 34 multipurpose workers working in an ICDS project about growth monitoring was assessed using interview technique. All workers had correct knowledge about rationale of growth monitoring. A total of 73.5% and 94.1% had knowledge that flattened growth curve indicates no weight gain and descending growth indicates decrease in weight, respectively.

Quantifying long-term population growth rates of threatened bull trout: challenges, lessons learned, and opportunities

Science.gov (United States)

Budy, Phaedra; Bowerman, Tracy; Al-Chokhachy, Robert K.; Conner, Mary; Schaller, Howard

2017-01-01

Temporal symmetry models (TSM) represent advances in the analytical application of mark–recapture data to population status assessments. For a population of char, we employed 10 years of active and passive mark–recapture data to quantify population growth rates using different data sources and analytical approaches. Estimates of adult population growth rate were 1.01 (95% confidence interval = 0.84–1.20) using a temporal symmetry model (λTSM), 0.96 (0.68–1.34) based on logistic regressions of annual snorkel data (λA), and 0.92 (0.77–1.11) from redd counts (λR). Top-performing TSMs included an increasing time trend in recruitment (f) and changes in capture probability (p). There was only a 1% chance the population decreased ≥50%, and a 10% chance it decreased ≥30% (λMCMC; based on Bayesian Markov chain Monte Carlo procedure). Size structure was stable; however, the adult population was dominated by small adults, and over the study period there was a decline in the contribution of large adults to total biomass. Juvenile condition decreased with increasing adult densities. Utilization of these different information sources provided a robust weight-of-evidence approach to identifying population status and potential mechanisms driving changes in population growth rates.

Effects of growth curve plasticity on size-structured population dynamics

DEFF Research Database (Denmark)

Zhang, Lai; Lin, Zhigui; Pedersen, Michael

2011-01-01

The physiological-structured population models assume that a fixed fraction of energy intake is utilized for individual growth and maintenance while the remaining for adult fertility. The assumption results in two concerns: energy loss for juveniles and a reproduction dilemma for adults. The dile...

Age-Specific Mortality and Fertility Rates for Probabilistic Population Projections

OpenAIRE

Ševčíková, Hana; Li, Nan; Kantorová, Vladimíra; Gerland, Patrick; Raftery, Adrian E.

2015-01-01

The United Nations released official probabilistic population projections (PPP) for all countries for the first time in July 2014. These were obtained by projecting the period total fertility rate (TFR) and life expectancy at birth ($e_0$) using Bayesian hierarchical models, yielding a large set of future trajectories of TFR and $e_0$ for all countries and future time periods to 2100, sampled from their joint predictive distribution. Each trajectory was then converted to age-specific mortalit...

The relationship between population ageing and the economic growth in Asia

Science.gov (United States)

Brendan, Lo Rick; Sek, Siok Kun

2017-08-01

Asia has witnessed robust economic growth since the 1960s. Today, emerging markets in Asia have managed to maintain rapid growth even when the world's main economies suffer from debt and banking crises. However, declining total fertility rate, increasing life expectancy, continuous change of birth and death patterns, and increasing share of old age population in the age distribution in Asia exert significant pressure on its economies. This paper analyses the relationship between population ageing and economic growth using 2 different panels of countries; one Asian and another the from the oldest countries worldwide between 1970 and 2014. The analysis is based on the Auto Regression Distributed Lag models. The MG (Mean Group) and PMG (Pooled Mean Group) estimations are applied in this analysis. The Hausman Test is conducted to decide between the MG and PMG estimators. We find that ageing will negatively affect the economy in the long run. The growing number of youths will initially have a negative effect on the economy but would eventually lead to a positive growth in the future. The old age dependency ratio has yet to have affect the Asian economy but is expected eventually to impose a negative effect as seen in the oldest nations of the world.

Growth and physiological responses to varied environments among populations of Pinus ponderosa

Science.gov (United States)

Jianwei Zhang; Bert M. Cregg

2005-01-01

We investigated population responses in physiology, morphology, and growth of mature Pinus ponderosa trees to an environmental gradient across Nebraska, USA. Ten populations from western Nebraska and eastern Wyoming were grown in three 26-year-old provenance tests from the warmest and wettest site in the east (Plattsmouth) to the intermediate site in...

Causes of mortality in California sea otters during periods of population growth and decline

Science.gov (United States)

Estes, J.A.; Hatfield, B.B.; Ralls, K.; Ames, J.

2003-01-01

Elevated mortality appears to be the main reason for both sluggish growth and periods of decline in the threatened California sea otter population. We assessed causes of mortality from salvage records of 3,105 beach-cast carcasses recovered from 1968 through 1999, contrasting two periods of growth with two periods of decline. Overall, an estimated 40%-60% of the deaths were not recovered and 70% of the recovered carcasses died from unknown causes. Nonetheless, several common patterns were evident in the salvage records during the periods of population decline. These included greater percentages of (1) prime age animals (3-10 yr), (2) carcasses killed by great white shark attacks, (3) carcasses recovered in spring and summer, and (4) carcasses for which the cause of death was unknown. Neither sex composition nor the proportion of carcasses dying of infectious disease varied consistently between periods of population increase and decline. The population decline from 1976 to 1984 was likely due to incidental mortality in a set-net fishery, and the decline from 1995 to 1999 may be related to a developing live-fish fishery. Long-term trends unrelated to periods of growth and decline included a decrease in per capita pup production and mass/length ratios of adult carcasses over the 31-yr study. The generally high proportion of deaths from infectious disease suggests that this factor has contributed to the chronically sluggish growth rate of the California sea otter population.

Differences in Townsend's chipmunk populations between second- and old-growth forests in western Oregon

Science.gov (United States)

D.K. Rosenberg; R.G. Anthony

1993-01-01

Because Townsend's chipmunks (Tomias townsendii) may be important in maintaining natural ecosystem processes in forests in the central Oregon Cascade Range, we compared their population characteristics in young second-growth and old-growth forests. We live-trapped Townsend's chipmunks in 5 young (30-60 yr old) second-growth and 5 old-...

Global fertility and population trends.

Science.gov (United States)

Bongaarts, John

2015-01-01

Over the past several decades, the world and most countries have undergone unprecedented demographic change. The most obvious example of this change is the rise in human numbers, and there are also important trends in fertility, family structure, mortality, migration, urbanization, and population aging. This paper summarizes past trends and projections in fertility and population. After reaching 2.5 billion in 1950, the world population grew rapidly to 7.2 billion in 2013 and the projections expect this total to be 10.9 billion by 2100. World regions differ widely in their demographic trends, with rapid population growth and high fertility continuing in the poorest countries, particularly in sub-Saharan Africa, while population decline, population aging, and very low fertility are now a key concern in many developed countries. These trends have important implications for human welfare and are of interest to policy makers. The conclusion comments briefly on policy options to address these adverse trends. Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.

Population pressures in Latin America. [Updated reprint].

Science.gov (United States)

Merrick, T W

1991-04-01

This publication examines the main demographic changes in Latin America since World War II, and considers their social and economic impact on the region. The paper looks at the following demographic trends: population growth, fertility, death rate, internal migration, international migration, and age structure. It also examines other factors such as marriage and family structure, and employment and education. Furthermore, the publication provides a discussion of the relationship between population growth and economic development from both a neo-Malthusian and Structuralist view. Finally, the paper considers the region's current population policies and future population prospects. From 1950-65, annual population growth averaged 2.8%, which decreased moderately to 2.4% from 1965-85. The report identified 3 population growth patterns in the region: 1) countries which experienced early and gradual declines in birth and death rates and generally lower population growth rates (the group includes Argentina, Cuba, Uruguay, with Chile and Panama also closely fitting the description); 2) countries which underwent rapid declines in birth rate during the 1950s and which began experiencing declines in the birth rate after 1960 (Brazil, Colombia, Costa Rica, the Dominican Republic, Mexico, Paraguay, and Venezuela, with Ecuador and Peru as borderline cases); and 3) countries which didn't begin to experience declines in mortality rates until relatively late and which lag behind in fertility declines (Bolivia, Haiti, El Salvador, Guatemala, Honduras, and Nicaragua). Although population growth has slowed and will continue to fall, UN projections do not expect the population to stabilize until late in the 21st Century.

World population in transition.

Science.gov (United States)

Merrick, T W

1986-04-01

The world's population growth rate peaked at slightly over 2%/year in the late 1960s and in 1986 is down to 1.7% and falling. Annual numbers added continue to rise because these rates apply to a very large base, 4.9 billion in 1986. According to UN medium variant projections, world population growth will peak at 89 million/year in the late 1990s and then taper off until world population stabilizes in the late decade of the 21st century at about 10.2 billion. Close to 95% of this growth is occurring in less developed countries (LDCs) of Africa, Asia (minus Japan), and Latin America. LDC fertility rates are declining, except in sub-Saharan Africa and parts of Latin America and South Asia, but most have far to go to reach the replacement level of 2.1 births/woman. Fertility is below replacement in virtually all more developed countries. For LDCs, large numbers will be added before stabilization even after attainment of replacement level fertility because of the demographic momentum built into their large and young population bases. This complicates efforts to bridge gaps between living standards in LDCs and industrialized countries. From a new debate about whether rapid population growth deters or stimulates economic growth, a more integrated view has emerged. This view recognizes the complementary relationship between efforts to slow population growth and other development efforts; e.g., to improve health and education, upgrade women's status, increase productivity. Most effective in the increased contraceptive prevalence and fertility declines seen in many LDCs has been the combination of organized programs to increase access to family planning information and supplies with socioeconomic development that enhances the desire for smaller families.

Headship Rate for Population Projection in Johor Bahru

Directory of Open Access Journals (Sweden)

Rawan Nurfilzah Mohamad

2017-01-01

Full Text Available Headship rate method is used to forecast population for housing demand. This paper presents the application of the method for forecasting population in Johor Bahru metropolitan city in Malaysia. Data used in the projection was based on census data of Johor Bahru provided by Department of Statistic Malaysia for the period of three years. Headship rate can be determined based on the ratio of head of household in age group by its age group total population. Hence, the purpose for this study is to compare a headship rate in Johor Bahru in year 1980, 2000 and 2010. The finding for the study shows that the male headship rate is higher than female headship rate in the 3 years’ time. For the male, the highest headship rate identified in age group 50-54 years old while for the female, the highest headship rate identified in age group 65-69 years old.

Population and labour force projections for 27 European countries, 2002-052: impact of international migration on population ageing: Projections de population et de population active pour 27 pays européens 2002-052: impact de la migration internationale sur le vieillissement de la population.

Science.gov (United States)

Bijak, Jakub; Kupiszewska, Dorota; Kupiszewski, Marek; Saczuk, Katarzyna; Kicinger, Anna

2007-03-01

Population and labour force projections are made for 27 selected European countries for 2002-052, focussing on the impact of international migration on population and labour force dynamics. Starting from single scenarios for fertility, mortality and economic activity, three sets of assumptions are explored regarding migration flows, taking into account probable policy developments in Europe following the enlargement of the EU. In addition to age structures, various support ratio indicators are analysed. The results indicate that plausible immigration cannot offset the negative effects of population and labour force ageing.

Are whooping cranes destined for extinction? Climate change imperils recruitment and population growth.

Science.gov (United States)

Butler, Matthew J; Metzger, Kristine L; Harris, Grant M

2017-04-01

Identifying climatic drivers of an animal population's vital rates and locating where they operate steers conservation efforts to optimize species recovery. The population growth of endangered whooping cranes ( Grus americana ) hinges on juvenile recruitment. Therefore, we identify climatic drivers (solar activity [sunspots] and weather) of whooping crane recruitment throughout the species' life cycle (breeding, migration, wintering). Our method uses a repeated cross-validated absolute shrinkage and selection operator approach to identify drivers of recruitment. We model effects of climate change on those drivers to predict whooping crane population growth given alternative scenarios of climate change and solar activity. Years with fewer sunspots indicated greater recruitment. Increased precipitation during autumn migration signified less recruitment. On the breeding grounds, fewer days below freezing during winter and more precipitation during breeding suggested less recruitment. We predicted whooping crane recruitment and population growth may fall below long-term averages during all solar cycles when atmospheric CO 2 concentration increases, as expected, to 500 ppm by 2050. Species recovery during a typical solar cycle with 500 ppm may require eight times longer than conditions without climate change and the chance of population decline increases to 31%. Although this whooping crane population is growing and may appear secure, long-term threats imposed by climate change and increased solar activity may jeopardize its persistence. Weather on the breeding grounds likely affects recruitment through hydrological processes and predation risk, whereas precipitation during autumn migration may influence juvenile mortality. Mitigating threats or abating climate change should occur within ≈30 years or this wild population of whooping cranes may begin declining.

Effects of temperature and population density on von Bertalanffy growth parameters in Atlantic herring: a macro-ecological analysis

NARCIS (Netherlands)

Brunel, T.P.A.; Dickey-Collas, M.

2010-01-01

The effect of temperature and population density on the growth of Atlantic herring Clupea harengus was studied using a comparative approach applied to 15 North Atlantic populations. The von Bertalanffy (VB) equation was applied to describe mean growth of individuals in each population, both averaged

Population growth, demographic change, and cultural landscapes.

Science.gov (United States)

Woodgate, G; Sage, C

1994-01-01

The inclusion of both ecological and socioeconomic components within landscapes makes possible the perception of the hierarchical character of landscape organization. A research approach is needed to conceptualize cultural landscapes as the product of interaction between society and nature. Richard Norgaard's 1984 paper on coevolutionary agricultural development attempts to meet this challenge. Coevolution is the interactive synthesis of natural and social mechanisms of change that characterize the relationship between social systems and ecosystems. The relationship between population, consumption, and environmental changes is complex. Currently industrialized countries present the biggest threat to global environmental resources. The issue of carrying capacity is the corollary of population and the environment. It is primarily the technological factor rather than population that needs to be controlled. The relationship between rich and poor countries is determined by superior economic power. An analysis of landscape change is made, tracing the coevolution of society and environment from the end of the feudal era and making comparisons with continental Europe. Over the years since 1945 the need to realize potential economies of scale has resulted in a wholesale loss of woodlands, hedgerows, and small ponds in the UK. In a global context the likely impacts of population growth and demographic change on landscapes will be influenced by such socioeconomic factors as technology and affluence; policies that ignore cause and effect; and the traditional tendency to treat the environment as a waste repository and a supply depot.

The relationship between population growth and poverty in Africa: a ...

African Journals Online (AJOL)

The mainstream view from these debates and discussions is that rapid population growth in Africa has put pressure on the environment, leading to environmental degradation which translates into shortfall in food production and atrophied development. This view is as a result of ritualistic adherence to narrow ideological ...

Posttraumatic Growth in Youth Survivors of a Disaster: An Arts-Based Research Project

Science.gov (United States)

Mohr, Elizabeth

2014-01-01

Evidence that posttraumatic growth is a potential outcome in the process of recovery from trauma and natural disaster highlights the importance of social environmental factors that encourage a growth response in survivors. This art-based research project followed up on a group of youth survivors (N = 11) of the 2007 earthquake in the Ica region of…

The Influence of Slope and Shelf Contour Currents On The Growth Pattern of A Cold-water Coral Mound Population Along The Margins of The Rockall Trough

Science.gov (United States)

Readman, P. W.; O'Reilly, B. M.; Shannon, P. M.; Jacob, A. W. B.

The importance of bottom currents along the shelf and slope regions of northeast At- lantic basin margins in controlling sediment transport patterns and the development of carbonate mound ecosystems is now well recognised. The detailed structure of one such large carbonate mound population has been resolved along the western margin of the Porupine Bank west of Ireland with deep-tow (TOBI) sidescan. The mounds which comprise the population are circular to elliptical in shape, 50 - 850 m across and up to about 200 m high. Large scale sedimentary bedforms at 800 m water depth are inferred from backscatter zonation produced by strong NE-flowing contour currents. Streamlining effects control the shape of the mounds as they become more elliptical as their size increases. The frequency distribution follows a general power law which is determined by the biological growth rate of the mounds and the rate at which they colonise the substrate. At first bottom currents aid mound growth until they become so large that hydraulic drag forces retard their growth. In the recent past (late Pleistocene to present) if the number of mounds colonising the slope has increased exponentially with time while their growth rate slowed in response to fluid form drag forces, the observed population curve can be recovered. A model for evolution of the population predicts that these increased forces slow biological growth and cause a sharp fall-off in the number of mounds, also in agreement with observation. Correlation with late Pleistocene and Holocene climatic change suggests that the population is either very robust and relatively insensitive to major environmental change along the continental slope such as a change in current regime, or that the factors controlling its develop- ment were stable over large time intervals. This project was undertaken on behalf of the Irish Petroleum Infrastructure Programme.

Determining individual variation in growth and its implication for life-history and population processes using the empirical Bayes method.

Directory of Open Access Journals (Sweden)

Simone Vincenzi

2014-09-01

Full Text Available The differences in demographic and life-history processes between organisms living in the same population have important consequences for ecological and evolutionary dynamics. Modern statistical and computational methods allow the investigation of individual and shared (among homogeneous groups determinants of the observed variation in growth. We use an Empirical Bayes approach to estimate individual and shared variation in somatic growth using a von Bertalanffy growth model with random effects. To illustrate the power and generality of the method, we consider two populations of marble trout Salmo marmoratus living in Slovenian streams, where individually tagged fish have been sampled for more than 15 years. We use year-of-birth cohort, population density during the first year of life, and individual random effects as potential predictors of the von Bertalanffy growth function's parameters k (rate of growth and L∞ (asymptotic size. Our results showed that size ranks were largely maintained throughout marble trout lifetime in both populations. According to the Akaike Information Criterion (AIC, the best models showed different growth patterns for year-of-birth cohorts as well as the existence of substantial individual variation in growth trajectories after accounting for the cohort effect. For both populations, models including density during the first year of life showed that growth tended to decrease with increasing population density early in life. Model validation showed that predictions of individual growth trajectories using the random-effects model were more accurate than predictions based on mean size-at-age of fish.

Determining individual variation in growth and its implication for life-history and population processes using the empirical Bayes method.

Science.gov (United States)

Vincenzi, Simone; Mangel, Marc; Crivelli, Alain J; Munch, Stephan; Skaug, Hans J

2014-09-01

The differences in demographic and life-history processes between organisms living in the same population have important consequences for ecological and evolutionary dynamics. Modern statistical and computational methods allow the investigation of individual and shared (among homogeneous groups) determinants of the observed variation in growth. We use an Empirical Bayes approach to estimate individual and shared variation in somatic growth using a von Bertalanffy growth model with random effects. To illustrate the power and generality of the method, we consider two populations of marble trout Salmo marmoratus living in Slovenian streams, where individually tagged fish have been sampled for more than 15 years. We use year-of-birth cohort, population density during the first year of life, and individual random effects as potential predictors of the von Bertalanffy growth function's parameters k (rate of growth) and L∞ (asymptotic size). Our results showed that size ranks were largely maintained throughout marble trout lifetime in both populations. According to the Akaike Information Criterion (AIC), the best models showed different growth patterns for year-of-birth cohorts as well as the existence of substantial individual variation in growth trajectories after accounting for the cohort effect. For both populations, models including density during the first year of life showed that growth tended to decrease with increasing population density early in life. Model validation showed that predictions of individual growth trajectories using the random-effects model were more accurate than predictions based on mean size-at-age of fish.

Economic implications of Japan's aging population: a macro-economic demographic modeling approach.

Science.gov (United States)

Ogawa, N

1982-01-01

This paper utilizes a macroeconomic demographic model to analyze the probable impact of population aging on various public programs in Japan. Rapid fertility decline aided by mortality decline has caused the proportion of the Japanese population aged 65 and over to increase from 4.9% in 1950 to 9.0% in 1980. A population projection based on the 1975 population census assumes a recovery of fertility from a total fertility rate (TFR) of 1.9 in 1976 to 2.16 in 1980 and a gradual decline to 2.1 by 1987, while an alternative projection assumes a continuing fertility decline to a TFR of 1.65 in 2025. According to these assumptions, in 2025 18.12% to 21.29% of the total population would be aged 65 or over and 38.66% to 43.80% of the working age population would be aged 45-64. A macroeconomic neoclassical growth model with some Keynesian features was formulated to evaluate the future impact of population aging on social security programs. Population changes are transmitted to economic variables in the model through the supply of labor, level of savings, public health care plans, and old-age pension schemes. The simulation experiments included the 2 population projections and 2 alternative production functions, 1 with the quality of labor incorporated and 1 without. The results indicated that, regardless of the population projection and production function used, the growth of the economy is likely to slow to 1 or 0% in the beginning of the next century due to decreased growth of the labor force and a change in its quality due to age-compositional variations. Public health insurance schemes and pension plans will require increasing financial resources as a result of accelerated population aging; depending on the choice of benefit levels, the proportion of national income allocated to them is expected to range from 14%-40% in the year 2010. Per capita gross national product will continue to grow despite decreased economic growth, but savings might be adversely affected if the

Optimal fetal growth for the Caucasian singleton and assessment of appropriateness of fetal growth: an analysis of a total population perinatal database

Directory of Open Access Journals (Sweden)

Lawrence David M

2005-05-01

Full Text Available Abstract Background The appropriateness of an individual's intra uterine growth is now considered an important determinant of both short and long term outcomes, yet currently used measures have several shortcomings. This study demonstrates a method of assessing appropriateness of intrauterine growth based on the estimation of each individual's optimal newborn dimensions from routinely available perinatal data. Appropriateness of growth can then be inferred from the ratio of the value of the observed dimension to that of the optimal dimension. Methods Fractional polynomial regression models including terms for non-pathological determinants of fetal size (gestational duration, fetal gender and maternal height, age and parity were used to predict birth weight, birth length and head circumference from a population without any major risk factors for sub-optimal intra-uterine growth. This population was selected from a total population of all singleton, Caucasian births in Western Australia 1998–2002. Births were excluded if the pregnancy was exposed to factors known to influence fetal growth pathologically. The values predicted by these models were treated as the optimal values, given infant gender, gestational age, maternal height, parity, and age. Results The selected sample (N = 62,746 comprised 60.5% of the total Caucasian singleton birth cohort. Equations are presented that predict optimal birth weight, birth length and head circumference given gestational duration, fetal gender, maternal height, age and parity. The best fitting models explained 40.5% of variance for birth weight, 32.2% for birth length, and 25.2% for head circumference at birth. Conclusion Proportion of optimal birth weight (length or head circumference provides a method of assessing appropriateness of intrauterine growth that is less dependent on the health of the reference population or the quality of their morphometric data than is percentile position on a birth weight

Impact of choice of future climate change projection on growth chamber experimental outcomes: a preliminary study in potato

Science.gov (United States)

Leisner, Courtney P.; Wood, Joshua C.; Vaillancourt, Brieanne; Tang, Ying; Douches, Dave S.; Robin Buell, C.; Winkler, Julie A.

2017-11-01

Understanding the impacts of climate change on agriculture is essential to ensure adequate future food production. Controlled growth experiments provide an effective tool for assessing the complex effects of climate change. However, a review of the use of climate projections in 57 previously published controlled growth studies found that none considered within-season variations in projected future temperature change, and few considered regional differences in future warming. A fixed, often arbitrary, temperature perturbation typically was applied for the entire growing season. This study investigates the utility of employing more complex climate change scenarios in growth chamber experiments. A case study in potato was performed using three dynamically downscaled climate change projections for the mid-twenty-first century that differ in terms of the timing during the growing season of the largest projected temperature changes. The climate projections were used in growth chamber experiments for four elite potato cultivars commonly planted in Michigan's major potato growing region. The choice of climate projection had a significant influence on the sign and magnitude of the projected changes in aboveground biomass and total tuber count, whereas all projections suggested an increase in total tuber weight and a decrease in specific gravity, a key market quality trait for potato, by mid-century. These results demonstrate that the use of more complex climate projections that extend beyond a simple incremental change can provide additional insights into the future impacts of climate change on crop production and the accompanying uncertainty.

An Assessment of Factors Affecting Population Growth of the Mountain Plover

Directory of Open Access Journals (Sweden)

Stephen J. Dinsmore

2010-06-01

Full Text Available Effective conservation measures should target the most sensitive life history attributes of a species, assuming they are responsive to potential management actions. The Mountain Plover (Charadrius montanus is a species of conservation concern with a patchy breeding distribution in western North America. Plovers prefer areas with short vegetation, bare ground, and disturbance for nesting. Current management tools, including grazing and burning, have been used to attract plovers and enhance nesting success. We used a stage-specific matrix model to study the influence of vital rates, e.g., juvenile and adult annual survival, on population growth rate in the Mountain Plover at two breeding sites in Colorado, South Park and Eastern Colorado, and one breeding site in Montana, USA. Our analysis was motivated by a need to 1 better understand the relationship between demographic rates and population growth rate, 2 assess current management tools for the plover by exploring their effect on population growth rate, and 3 identify areas of the plover's population biology where additional demographic work is needed. Stochastic population growth rate was most influenced by adult survival, especially in Montana and South Park, Colorado (elasticities > 0.60, and was least influenced by first-year reproduction (all elasticities < 0.20. The modeled relationships between lambda and each demographic rate were generally weak (r2 < 0.30 with the exception of number of eggs hatched per nest in Eastern Colorado (r2 = 0.63, chick survival in South Park (r2 = 0.40 and Montana (r2 = 0.38, and adult survival in Montana (r2 = 0.36. We examined the predicted increase in lambda that would result from increasing each demographic rate from its mean to the maximum value observed in our simulations. Chick and adult survival showed the greatest increase in lambda while eggs hatched per nest produced the smallest increase. Our results suggest that future conservation efforts should

Our population predicament: a new look.

Science.gov (United States)

Van Der Tak, J; Haub, C; Murphy, E

1979-12-01

Issued to mark the Population Reference Bureau's 50th anniversary, this issue updates the story of world population presented in its popular predecessor of 1971, "Man's Population Predicament." Estimated at 1/2 billion in 1650, world population reached about 2 billion in 1930, 4 billion in 1975, and is projected to be about 6 billion in 2000. Most of today's rapid growth is occurring among the 3/4 of the world's peoples living in less developed countries where the post-World War II gap between high birth rates and falling death rates has only recently begun to narrow. This growth, coupled with high consumption in developing countries, is putting tremendous pressures on the Earth's resources, environment, and social fabric. New evidence on Europe's population transition and from China, Indonesia, and Thailand in the 1970s suggests that well-designed family planning programs can speed fertility decline but rapid worldwide attainment of replacement level fertility will also require special development efforts and measures that go beyond family planning. Current projections of the world's ultimate peak population range from 8 billion in the mid 21st century to 11 billion in about 2125, depending on when replacement-level fertility is reached. China's drive for a drastic birth rate reduction and the oil crisis might change fertility behavior more rapidly than most demographers have heretofore thought likely.

Teaching Population Growth Using Cultures of Vinegar Eels, "Turbatrix aceti" (Nematoda)

Science.gov (United States)

Wallace, Robert L.

2005-01-01

A simple laboratory exercise is presented that follows the population growth of the common vinegar eel, "Turbatrix aceti" (Nematoda), in a microcosm using a simple culture medium. It lends itself to an exercise in a single semester course. (Contains 4 figures.)

Calculating second derivatives of population growth rates for ecology and evolution

NARCIS (Netherlands)

Shyu, E.; Caswell, H.

2014-01-01

Second derivatives of the population growth rate measure the curvature of its response to demographic, physiological or environmental parameters. The second derivatives quantify the response of sensitivity results to perturbations, provide a classification of types of selection and provide one way

Effect of Cadmium on the population growth of the marine diatom Chaetoceros gracilis Schutt

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Giovana Vera

2014-06-01

Full Text Available Phytoplankton constitutes the base of the trophic webs in the marine environment, so it is important to know the possible effects of pollutants on the algal populations. In the present paper the effect of cadmium on the population growth of the diatom Chaetoceros gracilis was assessed. The microalgae were cultured in the a modified “f/2” Guillard medium, and were exposed to different concentrations of cadmium between 50 and 100000 µg.–1, which produced an inhibitory effect from 20% to 99% on the population growth of Chaetoceros gracilis. Based on the dose (cadmium-response (inhibition relationship, a mean effective concentration (EC50% equal to 591 µg.L–1 of cadmium was obtained.

Population structure, growth and production of a recent brachiopod from the Chilean fjord region

KAUST Repository

Baumgarten, Sebastian

2013-12-04

Magellania venosa, the largest recent brachiopod, occurs in clusters and banks in population densities of up to 416 ind m-2 in Comau Fjord, Northern Chilean fjord region. Below 15 m, it co-occurs with the mytilid Aulacomya atra and it dominates the benthic community below 20 m. To determine the question of why M. venosa is a successful competitor, the in situ growth rate of the brachiopod was studied and its overall growth performance compared with that of other brachiopods and mussels. The growth in length was measured between February 2011 and March 2012 after mechanical tagging and calcein staining. Settlement and juvenile growth were determined from recruitment tiles installed in 2009 and from subsequent photocensus. Growth of M. venosa is best described by the general von Bertalanffy growth function, with a maximum shell length (L∞) of 71.53 mm and a Brody growth constant (K) of 0.336 year-1. The overall growth performance (OGP index = 5.1) is the highest recorded for a rynchonelliform brachiopod and in the range of that for Mytilus chilensis (4.8-5.27), but lower than that of A. atra (5.74). The maximal individual production (PInd) is 0.29 g AFDM ind-1 year-1 at 42 mm shell length and annual production ranges from 1.28 to 89.25 g AFDM year-1 m-2 (1-57% of that of A. atra in the respective fjords). The high shell growth rate of M. venosa, together with its high overall growth performance may explain the locally high population density of this brachiopod in Comau Fjord. However, the production per biomass of the population (P/B--ratio) is low (0.535) and M. venosa may play only a minor role in the food chain. Settling dynamics indicates that M. venosa is a pioneer species with low juvenile mortality. The coexistence of the brachiopod and bivalve suggests that brachiopod survival is affected by neither the presence of potential brachiopod predators nor that of space competitors (i.e. mytilids).

India in the Twenty-first Century: The Challenge of Population Growth. Fulbright-Hays Summer Seminars Abroad, 1997 (India).

Science.gov (United States)

La Fleur, Mary Ann

This paper contains a course outline for a five-hour graduate class focusing on the issue of population in India. Students examine contributing factors to population growth, along with studying characteristics of, and efforts to, control population growth. The significance of ethnic diversity in India also is addressed. Group discussion and group…

Population structure, growth and production of a recent brachiopod from the Chilean fjord region

KAUST Repository

Baumgarten, Sebastian; Laudien, Jü rgen; Jantzen, Carin; Hä ussermann, Verena; Fö rsterra, Gü nter

2013-01-01

-57% of that of A. atra in the respective fjords). The high shell growth rate of M. venosa, together with its high overall growth performance may explain the locally high population density of this brachiopod in Comau Fjord. However, the production per biomass

Mating system, population growth, and management scenario for Kalanchoe pinnata in an invaded seasonally dry tropical forest.

Science.gov (United States)

González de León, Salvador; Herrera, Ileana; Guevara, Roger

2016-07-01

Ecological invasions are a major issue worldwide, where successful invasion depends on traits that facilitate dispersion, establishment, and population growth. The nonnative succulent plant Kalanchoe pinnata, reported as invasive in some countries, is widespread in remnants of seasonally dry tropical forest on a volcanic outcrop with high conservation value in east-central Mexico where we assessed its mating system and demographic growth and identified management strategies. To understand its local mating system, we conducted hand-pollination treatments, germination, and survival experiments. Based on the experimental data, we constructed a life-stage population matrix, identified the key traits for population growth, weighted the contributions of vegetative and sexual reproduction, and evaluated management scenarios. Hand-pollination treatments had slight effects on fruit and seed setting, as well as on germination. With natural pollination treatment, the successful germination of seeds from only 2/39 fruit suggests occasional effective natural cross-pollination. The ratios of the metrics for self- and cross-pollinated flowers suggest that K. pinnata is partially self-compatible. Most of the pollinated flowers developed into fruit, but the seed germination and seedling survival rates were low. Thus, vegetative propagation and juvenile survival are the main drivers of population growth. Simulations of a virtual K. pinnata population suggest that an intense and sustained weeding campaign will reduce the population within at least 10 years. Synthesis and applications. The study population is partially self-compatible, but sexual reproduction by K. pinnata is limited at the study site, and population growth is supported by vegetative propagation and juvenile survival. Demographic modeling provides key insights and realistic forecasts on invasion process and therefore is useful to design management strategies.

Endogenous Population Dynamics and Economic Growth with Free Trade between Countries

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Wei-Bin Zhang

2016-05-01

Full Text Available This paper builds a model to deal with dynamic interdependence between different countries' birth rates, mortality rates, populations, wealth accumulation, and time distributions between working, leisure and children caring. The model shows the role of human capital, technological and preference changes on national differences in birth rates, mortality rates, time distributions, population change, and wealth accumulation. The economic mechanisms of wealth accumulation, production and trade are based the Solow growth model and the Oniki-Uzawa trade model. We use the utility function proposed by Zhang to describe the behavior of households. We model national and gender differences in human capital, propensity to have children, propensity to use leisure time, and children caring efficiency. We describe the dynamics of global economic growth, trade patterns, national differences in wealth, income, birth rates, mortality rates, and populations with differential equations. We simulate the model to show the motion of the system and identify the existence of equilibrium point. We also examine the effects of changes in the propensity to have children, the propensity to save, woman's propensity to use leisure, woman's human capital, and woman's emotional involvement in children caring on the dynamics of the global and national economies.

[Availability of physicians in Chile and its middle-term projection].

Science.gov (United States)

Goić, A

1994-02-01

The availability of active physicians in Chile and its 5 and 10 years projections were studied. The number of inhabitants was estimated using the 1992 National Population Census and the number of physicians, using the 1980 records of the Chilean College of Physicians (year in which enrollment was mandatory for all physicians). A 1.6% annual population growth rate and a 5% physician mortality rate was applied (slightly lower that the general population mortality rate). The annual retirement from professional practice was estimated in 0.5% and physicians over 70 years old were considered retired. According to these figures, in 1993 the population is 13,816,990 and there are 14,400 active physicians, a physician/inhabitant relationship of 1:960 (in 1980 it was 1:1,407). The estimated number agrees with that of the 1992 National Population Census and the 1993 income tax declarations. According to projections, in 1998 Chile will have 14,958,292 inhabitants, 16,770 physicians and an inhabitant/physician relationship of 1:921. The figures for year 2003 will be 16,193,867; 18,597 and 1:871 respectively. On the other hand, the study reveals a reduction in the number of admissions to medical schools and of graduated physicians and a reduction in the annual physician population growth rate from 5 to 2% (slightly higher than the general population growth rate). Depending on the economic growth estimations and the needs for medical attention for the next decade, the admission shares for medical schools should be revisited.

Fifty years of population growth and absorption of labor in Brazil: from 1950 to 2000.

Science.gov (United States)

Paiva, P D

1997-01-01

For a long time, the Brazilian population has grown at a relatively high rate, and only recently has the process of demographic transition intensified in the country. While the associated decline in fertility could result in a future decline in the size of the working-age population, it could also lead to an increase in female participation in the labor market. Brazil's economy is performing well, with gross domestic product (GDP) growing at an average annual rate of 7.1% during 1947-80. Marked growth in industrial employment opportunities has accompanied this growth in GDP. The size of the informal sector, however, has not decreased in similar proportion, while the 1981-83 economic crisis caused urban employment levels to drop, especially in industry and construction. Moreover, the level of rural-urban migration has increased and the agricultural employment index has fallen. The author evaluates past growth trends of the Economically Active Population (EAP) and of employment in Brazil, and assesses the potential growth of the labor force until the year 2000.

Prevalence and causes of blindness in a tropical African population ...

African Journals Online (AJOL)

It has a population of about 2, 654, 244 using the population growth rate of 3.0 percent per year. Egbedore LGA has a population of 49,555 being the projected estimate of the local census done in 1991. Study design: The study was in accordance with World Health Organisation recommendations. 3204 rural dwellers were ...

Growth Indicators of a 48-Clone Sugar Cane Population (Saccharum spp. with Forage Potential

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Yoslen Fernández Gálvez

2016-09-01

Full Text Available The aim of this paper was to determine growth indicators in a 48-clone sugar cane population, with promising phenotypical features for forage production. The following indicators were assessed: leaf area (A, leaf area index (LA1; leaf area ratio (LAR; specific leaf area (SLA; leaf weight ratio (LWR; crop growth rate (CGR; net assimilation rate (NAR; relative growth rate in weight (RGR; biomass production speed (G; leaf area duration (LAD; and biomass duration (Z, monthly (187 - 370 days. The minimum, the mean, the maximum values, and the population variance were determined for all cutting ages and the variables assessed. The results achieved have provided quantitative values that can be used as reference for selection and assessment of forage genotypes for ruminant nutrition.

Uropathogenic Escherichia coli Express Type 1 Fimbriae Only in Surface Adherent Populations Under Physiological Growth Conditions

DEFF Research Database (Denmark)

Stærk, Kristian; Kolmos, Hans Jørn; Khandige, Surabhi

2016-01-01

were correlated with the ability to adhere to and invade cultured human bladder cells. RESULTS:  Although inactive during planktonic growth in urine, T1F expression occurs when UPEC settles on and infects bladder epithelial cells or colonizes catheters. As a result, UPEC in these sessile populations...... with increased expression during surface growth adaptation and infection of uroepithelial cells. This leads to separation of UPEC into low-expression planktonic populations and high-expression sessile populations....... enhances bladder cell adhesion and invasion potential. Only T1F-negative UPEC are subsequently released to the urine, thus limiting T1F expression to surface-associated UPEC alone. CONCLUSION:  Our results demonstrate that T1F expression is strictly regulated under physiological growth conditions...

Status of India's population education programme--the subject of tripartite projects review and annual country review.

Science.gov (United States)

1981-12-01

A 3-step monitoring of India's population education program was undertaken in 1981 in order to determine the level of implementation and progress of the program. This monitoring program, conducted by the Unesco Mobile Team in collaboration with other institutions, followed 3 procedures: Project Progress Report (PPR); Tripartite Project Review (TPR); and Annual Country Review (ACR). The review meetings of the 10 state population education projects were organized at Chandigarh and Madras during August. The states covered in the review were Bihar, Haryana, Madhaya Pradesh, Punjab, Rajasthan, Chandigarh, Gujarat, Karnataka, Maharashtra, and Tamil Nadu. The Tripartite Review identified the following as problems which were hindering the smooth implementation of the population education program: 1) difficulty in spending funds unless certain formalities were completed by the governments of the states; 2) administrative problems such as getting printing paper for instructional materials, waiving the sales tax for equipment to be purchased under the project, and uncertainty regarding the admissible rates of per diem to be paid to the participants in various training programs; 3) the lack of experience of project staff; 4) problems created by having more than 1 cell in a state such as Rajasthan; and 5) an inadequate time frame within which the project should complete all its activities and make population education an integral part of the school system. The following were among the recommendations made: 1) the Project should be made coterminous with the 6th Five-Year Plan up to March 31, 1985; and 2) there should be only 1 Population Education Cell in every state. Among the points discussed at the annual country review, held during October, were the following: rephasing of the program from a 3 to 5 year project to synchronize it with the 6th plan; and the need for additional funds in view of inflation.

Is There Hidden Potential for Rural Population Growth in Sweden?

Science.gov (United States)

Niedomysl, Thomas; Amcoff, Jan

2011-01-01

Rural depopulation is a concern in many countries, and various policy initiatives have been taken to combat such trends. This article examines whether hidden potential for rural population growth can be found in Sweden. If such potential exists, it implies that the development prospects for many rural areas are not as unpromising as they may seem…

Africa's expanding population: old problems, new policies.

Science.gov (United States)

Goliber, T J

1989-11-01

Sub-Saharan Africa faces an historic challenge: to achieve economic and social progress while experiencing extraordinary population growth. With an estimated 1989 population of 512 million, the 42 countries of sub-Saharan Africa have the highest birth and death rates of any major world region. While death rates have fallen since the 1960s, persistently high birth rates yield annual growth rates above 3% in many countries. The United Nations projects that the region's population will increase 2.7 times by 2025--to 1.4 billion. Throughout the region, population has outstripped economic growth since the mid-1970s. In addition, many African countries are experiencing an epidemic of AIDS (Acquired Immunodeficiency Syndrome). The extent and demographic impact of the epidemic still are unknown, but disturbing social and political effects are already being felt. The region's population growth will slow only when African couples begin to have fewer children. The average number of children per woman ranges from 6 to 8 for most countries. The Africans' preference for large families is deeply rooted in the culture and fed by the perceived economic benefits they receive from their children. Economic stagnation during the 1980s prompted many national governments to recognize that rapid population growth was hindering their socioeconomic development. The political climate has shifted away from pronatalist or laissez-faire attitudes toward official policies to slow population growth. The policy formation process--detailed here for 4 countries (Zambia, Nigeria, Zaire, and Liberia)--is ponderous and beset with political and bureaucratic pitfalls, However, policy shifts in more and more countries combined with evidence of increased contraceptive use and fertility downturns in a few countries give some hope that the region's extraordinary population growth may have peaked and will start a descent. Whatever the case, the decade of the 1990s will be crucial for the future of sub

Population growth in a wild bird is buffered against phenological mismatch

NARCIS (Netherlands)

Reed, T.; Grotan, V.; Jenouvrier, S.; Saether, B.E.; Visser, M.E.

2013-01-01

road-scale environmental changes are altering patterns of natural selection in the wild, but few empirical studies have quantified the demographic cost of sustained directional selection in response to these changes. We tested whether population growth in a wild bird is negatively affected by

Open Innovation Projects in SMEs as an Engine for Sustainable Growth

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Byungun Yoon

2016-02-01

Full Text Available Most innovation activities that are inevitable for sustainable growth are coordinated via research and development (R&D projects, which can differ widely in terms of both project and open innovation characteristics, even when conducted within the same firm. Therefore, it is important to consider the peculiarities of R&D projects when evaluating the performance of open innovation strategies, as well as to explore how the benefits and costs of open innovation are shaped by cross-level interactions. This study identifies the differences between successful and unsuccessful open innovation projects, in both firm-level and project-level terms. We focus on small and medium enterprises (SMEs, which usually lack the full set of internal resources and competences required to effectively develop, produce, and commercialize their innovations, and thus must adopt open innovation approaches more actively for sustainability. Adopting an empirical approach, we conducted a survey of 517 Korean SMEs and analyzed 241 successful and unsuccessful open innovation projects in depth. By combining measurements at the firm and project levels, this study provides new insight into the intra-organizational challenges of implementing open innovation projects, which are not only helpful to strategic decision-makers in SMEs, but also to those who make policies for them.

Generation time, net reproductive rate, and growth in stage-age-structured populations

DEFF Research Database (Denmark)

Steiner, Uli; Tuljapurkar, Shripad; Coulson, Tim

2014-01-01

examples to show how reproductive timing Tc and level R0 are shaped by stage dynamics (individual trait changes), selection on the trait, and parent-offspring phenotypic correlation. We also show how population structure can affect dispersion in reproduction among ages and stages. These macroscopic...... to age-structured populations. Here we generalize this result to populations structured by stage and age by providing a new, unique measure of reproductive timing (Tc) that, along with net reproductive rate (R0), has a direct mathematical relationship to and approximates growth rate (r). We use simple...

Projected Regional Climate in 2025 Due to Urban Growth

Science.gov (United States)

Shepherd, J. Marshall; Manyin, Michael; Messen, Dmitry

2005-01-01

By 2025, 60 to 80 percent of the world s population will live in urban environments. Additionally, the following facts published by the United Nations further illustrates how cities will evolve in the future. Urban areas in the developing world are growing very rapidly. The urban growth rate will continue to be particularly rapid in the urban areas of less developed regions, averaging 2.4 per cent per year during 2000-2030, consistent with a doubling time of 29 years. The urbanization process will continue worldwide. The concentration of population in cities is expected to continue so that, by 2030, 84 percent of the inhabitants of more developed countries will be urban dwellers. Urbanization impacts the whole hierarchy of human settlements. In 2000,24.8 per cent of the world population lived in urban settlements with fewer than 500,000 inhabitants and by 2015 that proportion will likely rise to 27.1 per cent.

A note on the status of women as a factor in population growth in less developed countries.

Science.gov (United States)

Laidlaw, K A; Pugh, M D; Stockwell, E G

1980-01-01

The 1978 U.S. Bureau of the Census reported 4.3 billion as the world's population. 3.1 billion were living in the less developed areas where life is characterized by poverty and low levels of material well-being. In the develop countries the per capita income averaged $490, compared to $5,210 in developed areas. Little attention has been paid to the status of women in developing countries, where the impact of development often has a negative effect. As a measure of women's status, rates are given for male/female infant mortality. If the ratio is less than 1.14 the status of women is low. If the is 1.15-1.24 the status is medium. If the ratio is 1.25 and over, women enjoy high status. In countries where women have low status the population growth ra averages 3%. Where the status of women is medium, the growth rate is 2.5%. I countries of high status the population growth rate is 2.2. Further research is needed on correlations between population and economic growth, with particula emphasis on subtle factors behind population/economic development.

Nonylphenol stimulates fecundity but not population growth rate (λ) of Folsomia candida

DEFF Research Database (Denmark)

Widarto, T. H.; Krogh, P. H.; Forbes, V. E.

2007-01-01

of NP on these traits did not result in a statistically significant increase in population growth rate (λ). Decomposition analysis indicated that fecundity was the main contributor to the (non-significant) changes observed in λ However, since the elasticity of fecundity was very low, large changes...... at the population level and that λ is an appropriate endpoint for ecotoxicological studies. © 2007 Elsevier B.V. All rights reserved...

Development and population growth of Hydra viridissima Pallas, 1766 (Cnidaria, Hydrozoa in the laboratory

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FC. Massaro

Full Text Available Hydras, the most representative freshwater Cnidaria, are of common occurrence in bodies of water in every continent except Antarctica. This study was planned with the aim of maintaining a population of Hydra viridissima in laboratory culture to enable the determination of the individual and population growth-rates of this species, as well as its population doubling time and generation time, with a view to employing these common animals as test-organisms in ecotoxicological assays. The organisms were maintained in reconstituted water at 20 ± 2 °C, illuminated at 800 lux with a photoperiod of 12 hours light: 12 hours dark, and were fed on neonates of the cladoceran Ceriodaphnia silvestrii (3 or 4 neonates per hydra, 3 times a week. The individual growth-rate (k of the species was 0.43, the maximum length of the column 2.53 mm and the generation time 6.6 ± 1.5 days on average. The hydra population showed an intrinsic growth-rate (r of 0.0468, according to the fitted curve, and a doubling time of 14.8 ± 2.63 days. Hydra viridissima is easy to grow in the laboratory and performs well in the conditions used in this study. It is thus a promising candidate test-organism for ecotoxicological studies.

Variations in growth, survival and carbon isotope composition (delta(13)C) among Pinus pinaster populations of different geographic origins.

Science.gov (United States)

Correia, Isabel; Almeida, Maria Helena; Aguiar, Alexandre; Alía, Ricardo; David, Teresa Soares; Pereira, João Santos

2008-10-01

To evaluate differences in growth and adaptability of maritime pine (Pinus pinaster Ait.), we studied growth, polycyclism, needle tissue carbon isotope composition (delta(13)C) as an estimate of water-use efficiency (WUE) and survival of seven populations at 10 years of age growing in a performance trial at a provenance test site in Escaroupim, Portugal. Six populations were from relatively high rainfall sites in Portugal and southwestern France (Atlantic group), and one population was from a more arid Mediterranean site in Spain. There were significant differences between some populations in total height, diameter at breast height, delta(13)C of bulk needle tissue, polycyclism and survival. A population from central Portugal (Leiria, on the Atlantic coast) was the tallest and had the lowest delta(13)C. Overall, the variation in delta(13)C was better explained by the mean minimum temperatures of the coldest month than by annual precipitation at the place of origin. Analyses of the relationships between delta(13)C and growth or survival revealed a distinct pattern for the Mediterranean population, with low delta(13)C (and WUE) associated with the lowest growth potential and reduced survival. There were significant negative correlations between delta(13)C and height or survival in the Atlantic group. Variation in polycyclism was correlated with annual precipitation at the place of origin. Some Atlantic populations maintained a high growth potential while experiencing moderate water stress. A detailed knowledge of the relationships between growth, survival and delta(13)C in contrasting environments will enhance our ability to select populations for forestry or conservation.

Against all odds: Tales of survival and growth of the Foundational Approaches in Science Teaching (FAST) project

Science.gov (United States)

Yamamoto, Karen Kina

This study examines the dynamics of survival and growth of curricular and instructional innovations. It focuses on the Foundational Approaches in Science Teaching (FAST) project, a long-term survivor of reform in science education. Key questions guiding this study include: (1) How did the FAST project survive over the past 30 years? (2) What elements are essential for long-term survival and growth of an innovative science program? (3) Why did the project continue to survive amidst several waves of educational reform? The core of my conceptual framework is that the odds of survival and growth of curricular and instructional innovations are increased by the extent to which resources, theory-based curriculum development processes, and professional development strategies are not only incorporated into but also interdependent within a project. With this framework as a guide, the main methods of data collection were document analysis, interviews, and observations. FAST, developed by the University of Hawaii's Curriculum Research and Development Group (CRDG), consists of a sequential and interdisciplinary middle and high school science program for students in grades 6-10. According to the results of this study, the project was able to survive by receiving constant organizational support from CRDG and a steady source of State funding through the university since 1966; it also retained a relatively small but stable staff of highly qualified project personnel. Formulated on a discipline-based theory that values development of students' intellectual capacities as the platform for curriculum research, design, and development, the FAST project translated this vision of science education into key elements of an innovative program that survived and thrived: (1) an interdisciplinary program consisting of physical, biological, and earth sciences; inquiry as content and process; history and philosophy of science; and links between and among sciences, technology, and society; and (2

Fetal growth and psychiatric and socioeconomic problems: population-based sibling comparison.

Science.gov (United States)

Class, Quetzal A; Rickert, Martin E; Larsson, Henrik; Lichtenstein, Paul; D'Onofrio, Brian M

2014-11-01

It is unclear whether associations between fetal growth and psychiatric and socioeconomic problems are consistent with causal mechanisms. To estimate the extent to which associations are a result of unmeasured confounding factors using a sibling-comparison approach. We predicted outcomes from continuously measured birth weight in a Swedish population cohort (n = 3 291 773), while controlling for measured and unmeasured confounding. In the population, lower birth weight (⩽ 2500 g) increased the risk of all outcomes. Sibling-comparison models indicated that lower birth weight independently predicted increased risk for autism spectrum disorder (hazard ratio for low birth weight = 2.44, 95% CI 1.99-2.97) and attention-deficit hyperactivity disorder. Although attenuated, associations remained for psychotic or bipolar disorder and educational problems. Associations with suicide attempt, substance use problems and social welfare receipt, however, were fully attenuated in sibling comparisons. Results suggest that fetal growth, and factors that influence it, contribute to psychiatric and socioeconomic problems. Royal College of Psychiatrists.

Population and development.

Science.gov (United States)

Okita, S

1989-03-01

This speech on the life and work of Rafael Salas, who had been the first executive director of the UN Population Fund (UNFPA) and who contributed immensely to global awareness of population as a vital issue, inaugurated the Rafael M. Salas Lecture Series at the UN. Salas was concerned with individual rights and socioeconomic development while maintaining a balance between population and the environment. He built a large multinational assistance program for population activities and increased funding from $2.5 million in 1969 to $175 million to support 2500 projects in 130 developing countries. He organized both the 1974 World Population Conference and the 1984 International Conference on Population. In developing countries malnutrition and poverty are intertwined, lowering productivity and making people prone to diseases. Infant and child mortality rises with the malnutrition of mothers, therefore campaigns modelled after the postwar Japanese efforts are needed to improve nutrition, to train dietitians, and to introduce school lunch programs. Population stabilization could also be achieved in developing countries by raising income levels, although in Latin American countries birth rates have stayed the same despite increasing income. Direct measures are effective in reducing the birth rate: primary school education, increased income, improved nutrition, decline in infant mortality, higher status of women, and decisive governmental population policy. The Club of Rome report The Limits to Growth predicted that sometime in the 21st century a sudden decline in both population and industrial capacity will be reached at the present growth trends.

Trends in population growth in China's towns during the eighties, and town population in-migration and its decisive factors: a historic convergence of two types of demographic change.

Science.gov (United States)

Wei, J

1990-01-01

Relying on socioeconomic and population statistics, as well as population censuses, the author examines the growth of China's towns in the 1980s due to in-migration, and considers the economic causes and impact of the growth of towns. Prior to 1984, China's urbanization had been slow and uneven. But in the 4 years from 1984-87, China's urban population grew 3.8 times faster than the period before 1984. and unlike the previous pattern of urbanization, slightly over half of the urban growth occurred in small cities and towns. The rapid growth of towns was due to an unprecedented level of in-migration into towns from agricultural villages. This population transformed itself into a nonagricultural population. The author attributes the increase in urbanization and its changing patterns to a historic convergence: the shift in industry for the agricultural population and a regional shift for the village population--realized through a form of village-to-town population migration. The author goes on to examine the development of small-town enterprises, facilitated after the rural reform of 1984. The author notes that since that year, small-town industries have flourished, a development that has had a number of beneficial effects on both the provincial areas and the nation as a whole. Finally, the author considers the factors that have fueled town population in-migration: 1) in most provinces, higher incomes in towns have attracted people from the villages; and 2) in provinces with little discrepancy in income between town and village, a combination of the regions' relative isolation and government policy preventing migration to cities have spurred the growth of towns.

[The decline in the population growth rate--a priority issue in international politics].

Science.gov (United States)

Rhein, E

1994-08-25

The Third International UN Conference on Population and Development took place in Cairo in early September 1994 with the participation of 200 governments and 1000 nongovernmental organizations to discuss ways of stabilizing world population at the possible lowest level and how industrialized countries could contribute to this effort. As a consequence of the advances in reproductive medicine the use of contraceptives skyrocketed: in 1994 more than half of men and women were using contraception compared to only 5% in 1950. However, the demographic momentum would still increase world population for another 100 years, even if fertility would drop to 2.2 children per couple (compared to 4 children in 1990). Nevertheless, the present generation could be instrumental in deciding whether the world's population will remain around 8 billion or reach 12 billion between 2050 and 2150. Poor countries can no longer afford an annual growth rate of 2-4% while also trying to improve living standards; this would require an economic growth rate of 6-8%. For the control of population growth both a sustainable environmental policy in the North, with rapid transition to renewable energy and recycling, and a more effective population policy in the South are needed. Family planning (FP) is the precondition of stabilization. The global FP outlays are envisioned to double from the 1994 figure of $5 billion to over $10 billion in the year 2000, with donor contributions to increase from 20% to 40% of the total. The US contribution is to double from $500 million by 2000, while the European Commission decided to boost expenditures for FP from DM 30 million in 1994 to DM 600 million by 2000. Japan is also expending $3 billion during this period. Recent promising developments have emerged: national pronatalist policies have diminished sharply and the pronatalist influence of religions has also declined. Political commitment at the highest level is central to a successful population policy as

Nigerian CSM project ready to roll.

Science.gov (United States)

1985-01-01

Nigeria's contraceptive social marketing (CSM) project is ready to be launched. Population Services Intenational (PSI) had completed the groundwork for the project, funded primarily by a $200,000 grant from the nonpofit D.K. Tyagi Fund. The Population Crisis Committee also provided support for the new project. At presstime, PSI was negotiating for continued project funding from the US Agency for International Development (USAID) and The Futures Group. PSI already has identified suitable products, researched brand names, arranged for distribution, appointed an advertising agency, designed packaging, written a marketing plan, and taken steps to create a local, nonprofit marketing organization to manage the project. PSI has named Tim Barton as the resident manager. He will take up his post once the issue of future funding is resolved. Contraceptives now available are distributed through the private sector and by the Planned Parenthood Federation of Nigeria, the Local International Planned Parenthood Federation affiliate. Nigeria's annual rate of population growth is about 3% and the country is urbanizing rapidly. A 1983 fertility report revealed that only 14% of Nigerian women had ever used any type of contraception; 6% of married women were using a contraceptive method at the time of the survey.

The third population boom and corresponding macro-policies.

Science.gov (United States)

Tian, X

1990-01-01

China's birth peak between 1962-1973, and the expected 3rd peak beginning in 1986 has and will create a need for better, stable family planning measures; economic planning between 1990 and 2020 needs to accommodate the working population which in 2010 is expected to be 71.4% of the population (956 million); and a macro-strategic policy needs to be developed of the elderly who may constitute 17.44% of the population. The aging trend in China's working age population is expected to rise so rapidly that in 48 years, between 1982 and 2040, the over 65 population will quadruple ( a process in developed countries usually taking 80 years), thus creating a significant impact on a society with a low level of economic development. It is suggested that along with the growth in the national economy should come a state-provided welfare and retirement system, with reforms necessary to generate the additional income for elderly support; it is important that the cultural pattern of family care of the elderly remain intact. Assisting the able elderly in earning income in the service sector is encouraged. China's population has historically undergone 2 peak growth periods, between 1685 and 1830 with a 1% growth rate and between 1949-89 with an annual growth rate of 1.8%. The 2nd period is marked by 2 smaller peaks, one between 1953- 1957 with a growth rate of 2.38% and 1962-73 with a growth rate of 2.56%. A decline after 1974 changed to another upward cycle in 1986 with an increase to a 1.43 % growth rate expected to continue to 1996. The 1st peak between 1953-57 has already affected population control and the job market, and the fecund population is of concern because of the absolute size of the population, and because the planned limit for population growth of 1.2 billion by the year 2000 may be exceeded; and the projected rates, which have been increasing as expected, mean a population of 1.5 billion by 2050.

Data harmonization and federated analysis of population-based studies : the BioSHaRE project

NARCIS (Netherlands)

Doiron, Dany; Burton, Paul; Marcon, Yannick; Gaye, Amadou; Wolffenbuttel, Bruce H R; Perola, Markus; Stolk, Ronald P; Foco, Luisa; Minelli, Cosetta; Waldenberger, Melanie; Holle, Rolf; Kvaløy, Kirsti; Hillege, Hans L; Tassé, Anne-Marie; Ferretti, Vincent; Fortier, Isabel

2013-01-01

ABSTRACTS BACKGROUND: Individual-level data pooling of large population-based studies across research centres in international research projects faces many hurdles. The BioSHaRE (Biobank Standardisation and Harmonisation for Research Excellence in the European Union) project aims to address these

Stage-Structured Population Dynamics of AEDES AEGYPTI

Science.gov (United States)

Yusoff, Nuraini; Budin, Harun; Ismail, Salemah

Aedes aegypti is the main vector in the transmission of dengue fever, a vector-borne disease affecting world population living in tropical and sub-tropical countries. Better understanding of the dynamics of its population growth will help in the efforts of controlling the spread of this disease. In looking at the population dynamics of Aedes aegypti, this paper explored the stage-structured modeling of the population growth of the mosquito using the matrix population model. The life cycle of the mosquito was divided into five stages: eggs, larvae, pupae, adult1 and adult2. Developmental rates were obtained for the average Malaysian temperature and these were used in constructing the transition matrix for the matrix model. The model, which was based only on temperature, projected that the population of Aedes aegypti will blow up with time, which is not realistic. For further work, other factors need to be taken into account to obtain a more realistic result.

An application of the variable-r method to subpopulation growth rates in a 19th century agricultural population

Directory of Open Access Journals (Sweden)

Corey Sparks

2009-07-01

Full Text Available This paper presents an analysis of the differential growth rates of the farming and non-farming segments of a rural Scottish community during the 19th and early 20th centuries using the variable-r method allowing for net migration. Using this method, I find that the farming population of Orkney, Scotland, showed less variability in their reproduction and growth rates than the non-farming population during a period of net population decline. I conclude by suggesting that the variable-r method can be used in general cases where the relative growth of subpopulations or subpopulation reproduction is of interest.

POPULATION STRUCTURES OF FOUR TREE SPECIES IN LOGGED-OVER TROPICAL FOREST IN SOUTH PAPUA, INDONESIA: AN INTEGRAL PROJECTION MODEL APPROACH

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Relawan kuswandi

2015-12-01

Full Text Available Selective logging has been taking place in Papua for several decades. In contrast, very little is known about the stand structure in post-logged forest. Hence, this paper investigates stand structures in logged-over area of tropical forest in South Papua. Four species were selected in three one-hectare permanent sample plots (PSPs: Vatica rassak, Syzygium sp, Litsea timoriana and Canarium asperum. PSPs were located in the forest concession area of PT. Tunas Sawaerma in Assiki, Boven Digul, in South Papua. Data sets comprised measurements made in 2005 and 2012 consisting of species, diameter at breast height (DBH, mortality and number of tree of each species. Integral Projection Models (IPMs were developed, taking into account mortality, growth, recruitment and fecundity. Results show the pattern of stand structures of the four species were more or less similar, i.e. more individual trees were present in the small diameter classes than in the larger diameter classes. The general pattern of the individual distribution of the four species is the typical reverse-J shape. Syzygium sp. has a greater number of individuals in the small diameter classes than the other three species. Population growth rates (λ are above one, indicating that the stand structures of the population dynamics of the four species are recuperating. Conclusively, these results suggest that species composition and population structure in these logged-over forests are recovering increasingly.

Do social grants contribute to the jobless population growth in the former South African homelands?

CSIR Research Space (South Africa)

Geyer, H

2018-05-01

Full Text Available migration. A possible reason could be the high level of dependency on social grants in the former homelands. The article analyses population growth rates, economic growth rates and the ratio of social grant recipients within former homeland settlements...

Population dynamics and rural poverty.

Science.gov (United States)

Fong, M S

1985-01-01

An overview of the relationship between demographic factors and rural poverty in developing countries is presented. The author examines both the micro- and macro-level perspectives of this relationship and the determinants and consequences of population growth. The author notes the prospects for a rapid increase in the rural labor force and considers its implications for the agricultural production structure and the need for institutional change. Consideration is also given to the continuing demand for high fertility at the family level and the role of infant and child mortality in the poverty cycle. "The paper concludes by drawing attention to the need for developing the mechanism for reconciliation of social and individual optima with respect to family size and population growth." The need for rural development projects that take demographic factors into account is stressed as is the need for effective population programs. (summary in FRE, ITA) excerpt

Periodic matrix population models: growth rate, basic reproduction number, and entropy.

Science.gov (United States)

Bacaër, Nicolas

2009-10-01

This article considers three different aspects of periodic matrix population models. First, a formula for the sensitivity analysis of the growth rate lambda is obtained that is simpler than the one obtained by Caswell and Trevisan. Secondly, the formula for the basic reproduction number R0 in a constant environment is generalized to the case of a periodic environment. Some inequalities between lambda and R0 proved by Cushing and Zhou are also generalized to the periodic case. Finally, we add some remarks on Demetrius' notion of evolutionary entropy H and its relationship to the growth rate lambda in the periodic case.

Methodology of quality improvement projects for the Texas Medicare population.

Science.gov (United States)

Pendergrass, P W; Abel, R L; Bing, M; Vaughn, R; McCauley, C

1998-07-01

The Texas Medical Foundation, the quality improvement organization for the state of Texas, develops local quality improvement projects for the Medicare population. These projects are developed as part of the Health Care Quality Improvement Program undertaken by the Health Care Financing Administration. The goal of a local quality improvement project is to collaborate with providers to identify and reduce the incidence of unintentional variations in the delivery of care that negatively impact outcomes. Two factors are critical to the success of a quality improvement project. First, as opposed to peer review that is based on implicit criteria, quality improvement must be based on explicit criteria. These criteria represent key steps in the delivery of care that have been shown to improve outcomes for a specific disease. Second, quality improvement must be performed in partnership with the health care community. As such, the health care community must play an integral role in the design and evaluation of a quality improvement project and in the design and implementation of the resulting quality improvement plan. Specifically, this article provides a historical perspective for the transition from peer review to quality improvement. It discusses key steps used in developing and implementing local quality improvement projects including topic selection, quality indicator development, collaborator recruitment, and measurement of performance/improvement. Two Texas Medical Foundation projects are described to highlight the current methodology and to illustrate the impact of quality improvement projects.

POPULATION GROWTH AND PREFERENCE CHANGE IN A GENERALIZED SOLOW GROWTH MODEL WITH GENDER TIME DISTRIBUTIONS

Directory of Open Access Journals (Sweden)

Wei-Bin Zhang

2016-09-01

Full Text Available The study builds a model of dynamic interactions between the birth rate, the mortality rate, the population, wealth accumulation, time distribution between work, leisure and children caring, habit formation and preference change. The production technology and markets are built on the Solow growth model. We base our modeling the population dynamics on the Haavelmo population model and the Barro-Becker fertility choice model. This study takes account of habit formation and preference change. Although it is influenced by the Ramsey growth theory with time preference and habit formation, it uses Zhang’s approach to the household with habit formation and preference change. We synthesize different dynamic forces in a compact framework, using the utility function proposed by Zhang. Analytically, we focus on transitional processes as well as economic equilibrium. As the economic system is given by autonomous nonlinear differential equations, it is not easy to analyze its behavior. We simulate the model to demonstrate the existence of an equilibrium point and plot the motion of the dynamic system. We examine the effects of changes in weights given to the habit stock of children, the wife’s wage rate having negative impact on the propensity to have children, the wife weighing less the habit stock of leisure time, the wife’s habit stock of leisure time having negative impact on the husband’s propensity to use leisure time, the wife’s wage rate having negative impact on the husband’s propensity to use leisure time, woman’s human capital being improved, a rise in the total factor productivity, and the mother spending more time on each child fostering.

Growth Performance Of Mono-Sex And Mixed Sex Population Of ...

African Journals Online (AJOL)

The growth performance of all-male, all-female and mixed sex population of Oreochromis niloticus fed similar diet was carried out. The fingerlings used in the study were of relatively similar weight ranges (24.8 g – 26.6 g) with initial mean weight of 25.7±1.3 g and initial mean total length of 3.8 ± 1.5 cm. The mean increase ...

Living bacteria rheology: Population growth, aggregation patterns, and collective behavior under different shear flows

Science.gov (United States)

Patrício, P.; Almeida, P. L.; Portela, R.; Sobral, R. G.; Grilo, I. R.; Cidade, T.; Leal, C. R.

2014-08-01

The activity of growing living bacteria was investigated using real-time and in situ rheology—in stationary and oscillatory shear. Two different strains of the human pathogen Staphylococcus aureus—strain COL and its isogenic cell wall autolysis mutant, RUSAL9—were considered in this work. For low bacteria density, strain COL forms small clusters, while the mutant, presenting deficient cell separation, forms irregular larger aggregates. In the early stages of growth, when subjected to a stationary shear, the viscosity of the cultures of both strains increases with the population of cells. As the bacteria reach the exponential phase of growth, the viscosity of the cultures of the two strains follows different and rich behaviors, with no counterpart in the optical density or in the population's colony-forming units measurements. While the viscosity of strain COL culture keeps increasing during the exponential phase and returns close to its initial value for the late phase of growth, where the population stabilizes, the viscosity of the mutant strain culture decreases steeply, still in the exponential phase, remains constant for some time, and increases again, reaching a constant plateau at a maximum value for the late phase of growth. These complex viscoelastic behaviors, which were observed to be shear-stress-dependent, are a consequence of two coupled effects: the cell density continuous increase and its changing interacting properties. The viscous and elastic moduli of strain COL culture, obtained with oscillatory shear, exhibit power-law behaviors whose exponents are dependent on the bacteria growth stage. The viscous and elastic moduli of the mutant culture have complex behaviors, emerging from the different relaxation times that are associated with the large molecules of the medium and the self-organized structures of bacteria. Nevertheless, these behaviors reflect the bacteria growth stage.

The population crisis in sub-Saharan Africa.

Science.gov (United States)

Meerman, J; Cochrane, S H

1982-01-01

The authors argue that sub-Saharan Africa, given its present institutions and endowments of capital and technology, is already dangerously close to overpopulation. Specifically, they suggest that projected rapid population growth will have disastrous effects on the region's ability to increase exports and provide people with goods.

Effects of population density on the growth and egg-laying capacity ...

African Journals Online (AJOL)

The effects of the population density of adult African giant land snail, Archachatina marginata on the egg-laying capacity and the growth of the brooders and hatchlings were investigated for 9 months. Ten culture pens were stocked with snails at 20%, 40%, 60%, 80% and 100% capacity with each group in 2 replicates.

Stroke trends in an aging population. The Technology Assessment Methods Project Team.

Science.gov (United States)

Niessen, L W; Barendregt, J J; Bonneux, L; Koudstaal, P J

1993-07-01

Trends in stroke incidence and survival determine changes in stroke morbidity and mortality. This study examines the extent of the incidence decline and survival improvement in the Netherlands from 1979 to 1989. In addition, it projects future changes in stroke morbidity during the period 1985 to 2005, when the country's population will be aging. A state-event transition model is used, which combines Dutch population projections and existing data on stroke epidemiology. Based on the clinical course of stroke, the model describes historical national age- and sex-specific hospital admission and mortality rates for stroke. It extrapolates observed trends and projects future changes in stroke morbidity rates. There is evidence of a continuing incidence decline. The most plausible rate of change is an annual decline of -1.9% (range, -1.7% to -2.1%) for men and -2.4% (range, -2.3% to -2.8%) for women. Projecting a constant mortality decline, the model shows a 35% decrease of the stroke incidence rate for a period of 20 years. Prevalence rates for major stroke will decline among the younger age groups but increase among the oldest because of increased survival in the latter. In absolute numbers this results in an 18% decrease of acute stroke episodes and an 11% increase of major stroke cases. The increase in survival cannot fully explain the observed mortality decline and, therefore, a concomitant incidence decline has to be assumed. Aging of the population partially outweighs the effect of an incidence decline on the total burden of stroke. Increase in cardiovascular survival leads to a further increase in major stroke prevalence among the oldest age groups.

Human population growth offsets climate-driven increase in woody vegetation in sub-Saharan Africa

DEFF Research Database (Denmark)

Brandt, Martin Stefan; Rasmussen, Kjeld; Peñuelas, Josep

2017-01-01

The rapidly growing human population in sub-Saharan Africa generates increasing demand for agricultural land and forest products, which presumably leads to deforestation. Conversely, a greening of African drylands has been reported, but this has been difficult to associate with changes in woody...... an increase in woody cover largely in drylands, and 11% had a decrease (2,150,000 km2), mostly in humid zones. Increases in woody cover were associated with low population growth, and were driven by increases in CO2 in the humid zones and by increases in precipitation in drylands, whereas decreases in woody...... cover were associated with high population growth. The spatially distinct pattern of these opposing trends reflects, first, the natural response of vegetation to precipitation and atmospheric CO2, and second, deforestation in humid areas, minor in size but important for ecosystem services...

Age, growth and population structure of invasive lionfish (Pterois volitans/miles in northeast Florida using a length-based, age-structured population model

Directory of Open Access Journals (Sweden)

Eric G. Johnson

2016-12-01

Full Text Available The effective management of invasive species requires detailed understanding of the invader’s life history. This information is essential for modeling population growth and predicting rates of expansion, quantifying ecological impacts and assessing the efficacy of removal and control strategies. Indo-Pacific lionfish (Pterois volitans/miles have rapidly invaded the western Atlantic, Gulf of Mexico and Caribbean Sea with documented negative impacts on native ecosystems. To better understand the life history of this species, we developed and validated a length-based, age-structured model to investigate age, growth and population structure in northeast Florida. The main findings of this study were: (1 lionfish exhibited rapid growth with seasonal variation in growth rates; (2 distinct cohorts were clearly identifiable in the length-frequency data, suggesting that lionfish are recruiting during a relatively short period in summer; and (3 the majority of lionfish were less than two years old with no lionfish older than three years of age, which may be the result of culling efforts as well as ontogenetic habitat shifts to deeper water.

Age, growth and population structure of invasive lionfish (Pterois volitans/miles) in northeast Florida using a length-based, age-structured population model.

Science.gov (United States)

Johnson, Eric G; Swenarton, Mary Katherine

2016-01-01

The effective management of invasive species requires detailed understanding of the invader's life history. This information is essential for modeling population growth and predicting rates of expansion, quantifying ecological impacts and assessing the efficacy of removal and control strategies. Indo-Pacific lionfish ( Pterois volitans/miles ) have rapidly invaded the western Atlantic, Gulf of Mexico and Caribbean Sea with documented negative impacts on native ecosystems. To better understand the life history of this species, we developed and validated a length-based, age-structured model to investigate age, growth and population structure in northeast Florida. The main findings of this study were: (1) lionfish exhibited rapid growth with seasonal variation in growth rates; (2) distinct cohorts were clearly identifiable in the length-frequency data, suggesting that lionfish are recruiting during a relatively short period in summer; and (3) the majority of lionfish were less than two years old with no lionfish older than three years of age, which may be the result of culling efforts as well as ontogenetic habitat shifts to deeper water.

Social policy and population growth in South-East Asia.

Science.gov (United States)

You Poh Seng Rao, B; Shantakumar, G

1974-01-01

Social and population policies are considered for the 10 countries comprising Southeast Asia--Burma, Indonesia, the Khmer Republic, Laos, Malaysia, the Philippines, Singapore, Thailand, North Vietnam, and South Vietnam. All but Singapore have high fertility rates and Burma, Indonesia, the Khmer Republic, Laos and the two Vietnams have high mortality rates also. Government expenditures for education and social security systems is expanding throughout the region and it is hoped that their continued growth will contribute substantially to the effective implementation of population policies. Population policies in the 5 countries which have them are discussed. These are Indonesia, Malaysia, the Philippines, Singapore, and Thailand. It is noted, however, that declaration of policy is but the first step. Strategies and programs differ from one country to the next and depend very much on the stage of development, level of literacy, degree of urbanization, and other factors. Family planning activities generally are endogenous to urban social systems but exogenous to rural social systems. Thus, the rural elite has a large role to play in making population policies an integral part of rural life. The possibility is considered of developing workable incentive packages integrating health, education, and social security benefits with suitable emphasis on fertility reduction.

Stochastic resonance in a generalized Von Foerster population growth model

Energy Technology Data Exchange (ETDEWEB)

Lumi, N.; Mankin, R. [Institute of Mathematics and Natural Sciences, Tallinn University, 25 Narva Road, 10120 Tallinn (Estonia)

2014-11-12

The stochastic dynamics of a population growth model, similar to the Von Foerster model for human population, is studied. The influence of fluctuating environment on the carrying capacity is modeled as a multiplicative dichotomous noise. It is established that an interplay between nonlinearity and environmental fluctuations can cause single unidirectional discontinuous transitions of the mean population size versus the noise amplitude, i.e., an increase of noise amplitude can induce a jump from a state with a moderate number of individuals to that with a very large number, while by decreasing the noise amplitude an opposite transition cannot be effected. An analytical expression of the mean escape time for such transitions is found. Particularly, it is shown that the mean transition time exhibits a strong minimum at intermediate values of noise correlation time, i.e., the phenomenon of stochastic resonance occurs. Applications of the results in ecology are also discussed.

Optimal sampling plan for clean development mechanism lighting projects with lamp population decay

International Nuclear Information System (INIS)

Ye, Xianming; Xia, Xiaohua; Zhang, Jiangfeng

2014-01-01

Highlights: • A metering cost minimisation model is built with the lamp population decay to optimise CDM lighting projects sampling plan. • The model minimises the total metering cost and optimise the annual sample size during the crediting period. • The required 90/10 criterion sampling accuracy is satisfied for each CDM monitoring report. - Abstract: This paper proposes a metering cost minimisation model that minimises metering cost under the constraints of sampling accuracy requirement for clean development mechanism (CDM) energy efficiency (EE) lighting project. Usually small scale (SSC) CDM EE lighting projects expect a crediting period of 10 years given that the lighting population will decay as time goes by. The SSC CDM sampling guideline requires that the monitored key parameters for the carbon emission reduction quantification must satisfy the sampling accuracy of 90% confidence and 10% precision, known as the 90/10 criterion. For the existing registered CDM lighting projects, sample sizes are either decided by professional judgment or by rule-of-thumb without considering any optimisation. Lighting samples are randomly selected and their energy consumptions are monitored continuously by power meters. In this study, the sampling size determination problem is formulated as a metering cost minimisation model by incorporating a linear lighting decay model as given by the CDM guideline AMS-II.J. The 90/10 criterion is formulated as constraints to the metering cost minimisation problem. Optimal solutions to the problem minimise the metering cost whilst satisfying the 90/10 criterion for each reporting period. The proposed metering cost minimisation model is applicable to other CDM lighting projects with different population decay characteristics as well

Physical growth of the shuar: Height, Weight, and BMI references for an indigenous amazonian population.

Science.gov (United States)

Urlacher, Samuel S; Blackwell, Aaron D; Liebert, Melissa A; Madimenos, Felicia C; Cepon-Robins, Tara J; Gildner, Theresa E; Snodgrass, J Josh; Sugiyama, Lawrence S

2016-01-01

Information concerning physical growth among small-scale populations remains limited, yet such data are critical to local health efforts and to foster basic understandings of human life history and variation in childhood development. Using a large dataset and robust modeling methods, this study aims to describe growth from birth to adulthood among the indigenous Shuar of Amazonian Ecuador. Mixed-longitudinal measures of height, weight, and body mass index (BMI) were collected from Shuar participants (n = 2,463; age: 0-29 years). Centile growth curves and tables were created for each anthropometric variable of interest using Generalized Additive Models for Location, Scale, and Shape (GAMLSS). Pseudo-velocity and Lambda-Mu-Sigma curves were generated to further investigate Shuar patterns of growth and to facilitate comparison with United States Center for Disease Control and Prevention and multinational World Health Organization growth references. The Shuar are small throughout life and exhibit complex patterns of growth that differ substantially from those of international references. Similar to other Amazonians, Shuar growth in weight compares more favorably to references than growth in height, resulting in BMI curves that approximate international medians. Several additional characteristics of Shuar development are noteworthy, including large observed variation in body size early in life, significant infant growth faltering, extended male growth into adulthood, and a markedly early female pubertal growth spurt in height. Phenotypic plasticity and genetic selection in response to local environmental factors may explain many of these patterns. Providing a detailed reference of growth for the Shuar and other Amazonian populations, this study possesses direct clinical application and affords valuable insight into childhood health and the ecology of human growth. © 2015 Wiley Periodicals, Inc.

What's up in Kenya? (Besides population).

Science.gov (United States)

Yinger, N; Carty, W

1987-11-01

There are some indications that things are changing in Kenya, a nation with 1 of the world's fastest growing populations. Kenya's population will increase from the present 22.4 million to 44.8 million in the next 18 years if the 3.9% annual population growth rate remains constant. The government has renewed its campaign to increase awareness of the relationship between population growth and economic progress. There is not much progress to report as yet. Contraceptive prevalence is increasing slowly and now stands at 20% of eligible women. The government family planning program has been only minimally effective in recruiting or keeping family planning clients, but some smaller scale, private family planning programs demonstrate that Kenyans are receptive to family planning if they have access to appropriate and well-operated services. The key to the successful community-based program at Chogoria Hospital has been the use of the tradition of self-help. The original targets of the Family Planning Private Sector Project (FPPS), funded by the US Agency for International Development (USAID), have been met, and the new goals are for a total of 50 subprojects and 50,000 acceptors. The strategy of FPPS is to convince a company, plantation, para-state organization, private clinic, or school that its social and economic interests would be served by adopting a strong family planning program. The project then trains health clinic staff, and programs are designed to carry out the individual projects. Workers are educated about the economic and health benefits of smaller families and provided with appropriate information, contraceptives, and followup services. After 2 years of support, FPPS leaves the projects to the companies to operate and finance on a permanent basis. This approach works because Kenya has 1 of the largest and most socially responsible nongovernmental sectors in Africa. Project such as Chogoria and FPPS show that many Kenyans recognize the health and economic

Genetic variation in Pinus strobiformis growth and drought tolerance from southwestern US populations.

Science.gov (United States)

Goodrich, Betsy A; Waring, Kristen M; Kolb, Thomas E

2016-10-01

The persistence of some tree species is threatened by combinations of novel abiotic and biotic stressors. To examine the hypothesis that Pinus strobiformis Engelm., a tree threatened by an invasive forest pathogen and a changing climate, exhibits intraspecific genetic variation in adaptive traits, we conducted a common garden study of seedlings at one location with two watering regimes using 24 populations. Four key findings emerged: (i) growth and physiological traits were low to moderately differentiated among populations but differentiation was high for some traits in water-stressed populations; (ii) seedlings from warmer climates grew larger, had higher stomatal density and were more water-use efficient (as measured by the carbon isotope ratio) than populations from colder climates; (iii) seedlings from the northern edge of the species' distribution had lower water-use efficiency, higher stomatal conductance, slower growth and longer survival in a lethal drought experiment compared with seedlings from more southern populations; and (iv) based on non-metric multidimensional scaling analyses, populations clustered into southern and northern groups, which did not correspond to current seed transfer zones. Our discovery of a clinal geographic pattern of genetic variation in adaptive traits of P. strobiformis seedlings will be useful in developing strategies to maintain the species during ongoing climate change and in the face of an invasive pathogen. © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Maternal risk factors for abnormal placental growth: The national collaborative perinatal project

Directory of Open Access Journals (Sweden)

Nicholson Wanda K

2008-09-01

Full Text Available Abstract Background Previous studies of maternal risk factors for abnormal placental growth have focused on placental weight and placental ratio as measures of placental growth. We sought to identify maternal risk factors for placental weight and two neglected dimensions of placental growth: placental thickness and chorionic plate area. Methods We conducted an analysis of 24,135 mother-placenta pairs enrolled in the National Collaborative Perinatal Project, a prospective cohort study of pregnancy and child health. We defined growth restriction as th percentile and hypertrophy as > 90th percentile for three placental growth dimensions: placental weight, placental thickness and chorionic plate area. We constructed parallel multinomial logistic regression analyses to identify (a predictors of restricted growth (vs. normal and (b predictors of hypertrophic growth (vs. normal. Results Black race was associated with an increased likelihood of growth restriction for placental weight, thickness and chorionic plate area, but was associated with a reduced likelihood of hypertrophy for these three placental growth dimensions. We observed an increased likelihood of growth restriction for placental weight and chorionic plate area among mothers with hypertensive disease at 24 weeks or beyond. Anemia was associated with a reduced likelihood of growth restriction for placental weight and chorionic plate area. Pre-pregnancy BMI and pregnancy weight gain were associated with a reduced likelihood of growth restriction and an increased likelihood of hypertrophy for all three dimensions of placental growth. Conclusion Maternal risk factors are either associated with placental growth restriction or placental hypertrophy not both. Our findings suggest that the placenta may have compensatory responses to certain maternal risk factors suggesting different underlying biological mechanisms.

The interaction of human population, food production, and biodiversity protection.

Science.gov (United States)

Crist, Eileen; Mora, Camilo; Engelman, Robert

2017-04-21

Research suggests that the scale of human population and the current pace of its growth contribute substantially to the loss of biological diversity. Although technological change and unequal consumption inextricably mingle with demographic impacts on the environment, the needs of all human beings-especially for food-imply that projected population growth will undermine protection of the natural world. Numerous solutions have been proposed to boost food production while protecting biodiversity, but alone these proposals are unlikely to staunch biodiversity loss. An important approach to sustaining biodiversity and human well-being is through actions that can slow and eventually reverse population growth: investing in universal access to reproductive health services and contraceptive technologies, advancing women's education, and achieving gender equality. Copyright © 2017, American Association for the Advancement of Science.

Customized versus population-based growth curves: prediction of low body fat percent at term corrected gestational age following preterm birth.

Science.gov (United States)

Law, Tameeka L; Katikaneni, Lakshmi D; Taylor, Sarah N; Korte, Jeffrey E; Ebeling, Myla D; Wagner, Carol L; Newman, Roger B

2012-07-01

Compare customized versus population-based growth curves for identification of small-for-gestational-age (SGA) and body fat percent (BF%) among preterm infants. Prospective cohort study of 204 preterm infants classified as SGA or appropriate-for-gestational-age (AGA) by population-based and customized growth curves. BF% was determined by air-displacement plethysmography. Differences between groups were compared using bivariable and multivariable linear and logistic regression analyses. Customized curves reclassified 30% of the preterm infants as SGA. SGA infants identified by customized method only had significantly lower BF% (13.8 ± 6.0) than the AGA (16.2 ± 6.3, p = 0.02) infants and similar to the SGA infants classified by both methods (14.6 ± 6.7, p = 0.51). Customized growth curves were a significant predictor of BF% (p = 0.02), whereas population-based growth curves were not a significant independent predictor of BF% (p = 0.50) at term corrected gestational age. Customized growth potential improves the differentiation of SGA infants and low BF% compared with a standard population-based growth curve among a cohort of preterm infants.

Population growth and the decline of natural Southern yellow pine forests

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David B. South; Edward R. Buckner

2004-01-01

Population growth has created social and economic pressures that affect the sustainability of naturally regenerated southern yellow pine forests. Major causes of this decline include (1) a shift in public attitudes regarding woods burning (from one favoring it to one that favors fire suppression) and (2) an increase in land values (especially near urban centers). The...

Accounting for household heterogeneity in general equilibrium economic growth models

International Nuclear Information System (INIS)

Melnikov, N.B.; O'Neill, B.C.; Dalton, M.G.

2012-01-01

We describe and evaluate a new method of aggregating heterogeneous households that allows for the representation of changing demographic composition in a multi-sector economic growth model. The method is based on a utility and labor supply calibration that takes into account time variations in demographic characteristics of the population. We test the method using the Population-Environment-Technology (PET) model by comparing energy and emissions projections employing the aggregate representation of households to projections representing different household types explicitly. Results show that the difference between the two approaches in terms of total demand for energy and consumption goods is negligible for a wide range of model parameters. Our approach allows the effects of population aging, urbanization, and other forms of compositional change on energy demand and CO 2 emissions to be estimated and compared in a computationally manageable manner using a representative household under assumptions and functional forms that are standard in economic growth models.

Bone growth, limb proportions and non-specific stress in archaeological populations from Croatia.

Science.gov (United States)

Pinhasi, R; Timpson, A; Thomas, M; Slaus, M

2014-01-01

The effect of environmental factors and, in particular, non-specific stress on the growth patterns of limbs and other body dimensions of children from past populations is not well understood. This study assesses whether growth of mediaeval and post-mediaeval children aged between 0-11.5 years from Adriatic (coastal) and continental Croatia varies by region and by the prevalence and type of non-specific stress. Dental ages were estimated using the Moorrees, Fanning and Hunt (MFH) scoring method. Growth of long bone diaphyses (femur, tibia, humerus, radius and ulna) was assessed by using a composite Z-score statistic (CZS). Clavicular length was measured as a proxy for upper trunk width, distal metaphyseal width of the femur was measured as a proxy for body mass and upper and lower intra-limb indices were calculated. Differences between sub-sets sampled by (a) region and (b) active vs healed non-specific stress indicators and (c) intra-limb indices were tested by Mann--Whitney U-tests and Analysis of Covariance (ANCOVA). Adriatic children attained larger dimensions-per-age than continental children. Children with healed stress lesions had larger dimensions-per-age than those with active lesions. No inter-regional difference was found in intra-limb indices. These findings highlight the complexity of growth patterns in past populations and indicate that variation in environmental conditions such as diet and differences in the nature of non-specific stress lesions both exert a significant effect on long bone growth.

Increasing Dengue Incidence in Singapore over the Past 40 Years: Population Growth, Climate and Mobility.

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Claudio Jose Struchiner

Full Text Available In Singapore, the frequency and magnitude of dengue epidemics have increased significantly over the past 40 years. It is important to understand the main drivers for the rapid increase in dengue incidence. We studied the relative contributions of putative drivers for the rise of dengue in Singapore: population growth, climate parameters and international air passenger arrivals from dengue endemic countries, for the time period of 1974 until 2011. We used multivariable Poisson regression models with the following predictors: Annual Population Size; Aedes Premises Index; Mean Annual Temperature; Minimum and Maximum Temperature Recorded in each year; Annual Precipitation and Annual Number of Air Passengers arriving from dengue-endemic South-East Asia to Singapore. The relative risk (RR of the increase in dengue incidence due to population growth over the study period was 42.7, while the climate variables (mean and minimum temperature together explained an RR of 7.1 (RR defined as risk at the end of the time period relative to the beginning and goodness of fit associated with the model leading to these estimates assessed by pseudo-R2 equal to 0.83. Estimating the extent of the contribution of these individual factors on the increasing dengue incidence, we found that population growth contributed to 86% while the residual 14% was explained by increase in temperature. We found no correlation with incoming air passenger arrivals into Singapore from dengue endemic countries. Our findings have significant implications for predicting future trends of the dengue epidemics given the rapid urbanization with population growth in many dengue endemic countries. It is time for policy-makers and the scientific community alike to pay more attention to the negative impact of urbanization and urban climate on diseases such as dengue.

Impacts of invasive fish removal through angling on population characteristics and juvenile growth rate.

Science.gov (United States)

Evangelista, Charlotte; Britton, Robert J; Cucherousset, Julien

2015-06-01

Exploitation can modify the characteristics of fish populations through the selective harvesting of individuals, with this potentially leading to rapid ecological and evolutionary changes. Despite the well-known effects of invasive fishes on aquatic ecosystems generally, the potential effects of their selective removal through angling, a strategy commonly used to manage invasive fish, are poorly understood. The aim of this field-based study was to use the North American pumpkinseed Lepomis gibbosus as the model species to investigate the consequences of selective removal on their population characteristics and juvenile growth rates across 10 populations in artificial lakes in southern France. We found that the maximal individual mass in populations decreased as removal pressure through angling increased, whereas we did not observed any changes in the maximal individual length in populations as removal pressure increased. Total population abundance did not decrease as removal pressure increased; instead, here was a U-shaped relationship between removal pressure and the abundance of medium-bodied individuals. In addition, population biomass had a U-shaped curve response to removal pressure, implying that invasive fish populations can modulate their characteristics to compensate for the negative effects of selective removals. In addition, individual lengths at age 2 and juvenile growth rates decreased as removal pressure through angling increased, suggesting a shift toward an earlier size at maturity and an overall slower growing phenotype. Therefore, these outputs challenge the efficiency of selective management methods, suggesting the use of more proactive strategies to control invasive populations, and the need to investigate the potential ecological and evolutionary repercussions of nonrandom removal.

Can human populations be stabilized?

Science.gov (United States)

Warren, Stephen G.

2015-02-01

Historical examples of demographic change, in China, Italy, Nigeria, Utah, Easter Island, and elsewhere, together with simple mathematics and biological principles, show that stabilizing world population before it is limited by food supply will be more difficult than is generally appreciated. United Nations population projections are wrong because they assume, in spite of the absence of necessary feedbacks, that all nations will converge rapidly to replacement-level fertility and thereafter remain at that level. Education of women and provision of contraceptives have caused dramatic reductions in fertility, but many groups, including some that are well-educated, maintain high fertility. Small groups with persistent high fertility can grow to supplant low-fertility groups, resulting in continued growth of the total population. The global average fertility rate could rise even if each country's fertility rate is falling. In some low-fertility European countries where deaths exceed births, the population continues to grow because of immigration. Producing more than two offspring is normal for all animal species with stable populations because their populations are limited by resources or predation rather than birth control. It may therefore be appropriate to view the growth of human population as the result not of excess fertility but rather of excess food.

Projecting range-wide sun bear population trends using tree cover and camera-trap bycatch data.

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Lorraine Scotson

Full Text Available Monitoring population trends of threatened species requires standardized techniques that can be applied over broad areas and repeated through time. Sun bears Helarctos malayanus are a forest dependent tropical bear found throughout most of Southeast Asia. Previous estimates of global population trends have relied on expert opinion and cannot be systematically replicated. We combined data from 1,463 camera traps within 31 field sites across sun bear range to model the relationship between photo catch rates of sun bears and tree cover. Sun bears were detected in all levels of tree cover above 20%, and the probability of presence was positively associated with the amount of tree cover within a 6-km2 buffer of the camera traps. We used the relationship between catch rates and tree cover across space to infer temporal trends in sun bear abundance in response to tree cover loss at country and global-scales. Our model-based projections based on this "space for time" substitution suggested that sun bear population declines associated with tree cover loss between 2000-2014 in mainland southeast Asia were ~9%, with declines highest in Cambodia and lowest in Myanmar. During the same period, sun bear populations in insular southeast Asia (Malaysia, Indonesia and Brunei were projected to have declined at a much higher rate (22%. Cast forward over 30-years, from the year 2000, by assuming a constant rate of change in tree cover, we projected population declines in the insular region that surpassed 50%, meeting the IUCN criteria for endangered if sun bears were listed on the population level. Although this approach requires several assumptions, most notably that trends in abundance across space can be used to infer temporal trends, population projections using remotely sensed tree cover data may serve as a useful alternative (or supplement to expert opinion. The advantages of this approach is that it is objective, data-driven, repeatable, and it requires that

The little women of Loja--growth hormone-receptor deficiency in an inbred population of southern Ecuador.

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Rosenbloom, A L; Guevara Aguirre, J; Rosenfeld, R G; Fielder, P J

1990-11-15

Laron-type dwarfism, which is characterized by the clinical appearance of isolated growth hormone deficiency with elevated serum levels of growth hormone and decreased serum levels of insulin-like growth factor I (IGF-I), has been described in approximately 50 patients. This condition is caused by a deficiency of the cellular receptor for growth hormone, and it is transmitted as an autosomal recessive trait, as indicated by an equal sex distribution and a high rate of consanguinity in affected families. We studied 20 patients (19 females and 1 male, 2 to 49 years of age), from an inbred Spanish population in southern Ecuador, who had the clinical features of Laron-type dwarfism. Seventeen patients were members of two large pedigrees. Among the 13 affected sibships, there were 19 affected and 24 unaffected female siblings and 1 affected and 21 unaffected male siblings. The patients' heights ranged from 10.0 to 6.7 SD below the normal mean height for age in the United States. In addition to the previously described features, 15 patients had limited elbow extensibility, all had blue scleras, affected adults had relatively short extremities, and all four affected women over 30 years of age had hip degeneration. Basal serum concentrations of growth hormone were elevated in all affected children (30 to 160 micrograms per liter) and normal to moderately elevated in the adults. The serum level of growth hormone-binding protein ranged from 1 to 30 percent of normal; IGF-I concentrations were low--less than or equal to 7 micrograms per liter in the children and less than or equal to 66 micrograms per liter in the adults (normal for Ecuadorean women, 98 to 238). Serum levels of IGF-II and growth hormone-dependent IGF-binding protein-3 were also low. We describe an inbred population with a high incidence of growth hormone-receptor deficiency resulting in a clinical picture resembling Laron-type dwarfism but differing principally in showing a marked predominance of affected

Projecting the success of plant restoration with population viability analysis

Science.gov (United States)

Bell, T.J.; Bowles, M.L.; McEachern, A.K.; Brigham, C.A.; Schwartz, M.W.

2003-01-01

Conserving viable populations of plant species requires that they have high probabilities of long-term persistence within natural habitats, such as a chance of extinction in 100 years of less than 5% (Menges 1991, 1998; Brown 1994; Pavlik 1994; Chap. 1, this Vol.). For endangered and threatened species that have been severely reduces in range and whose habitats have been fragmented, important species conservation strategies may include augmenting existing populations or restoring new viable populations (Bowles and Whelan 1994; Chap. 2, this Vol.). Restoration objectives may include increasing population numbers to reduce extinction probability, deterministic manipulations to develop a staged cohort structure, or more complex restoration of a desired genetic structure to allow outcrossing or increase effective population size (DeMauro 1993, 1994; Bowles et al. 1993, 1998; Pavlik 1994; Knapp and Dyer 1998; Chap. 2, this Vol.). These efforts may require translocation of propagules from existing (in situ) populations, or from ex situ botanic gardens or seed storage facilities (Falk et al. 1996; Guerrant and Pavlik 1998; Chap. 2, this Vol.). Population viability analysis (PVA) can provide a critical foundation for plant restoration, as it models demographic projections used to evaluate the probability of population persistence and links plant life history with restoration strategies. It is unknown how well artificially created populations will meet demographic modeling requirements (e.g., due to artificial cohort transitions) and few, if any, PVAs have been applied to restorations. To guide application of PVA to restored populations and to illustrate potential difficulties, we examine effects of planting different life stages, model initial population sizes needed to achieve population viability, and compare demographic characteristics between natural and restored populations. We develop and compare plant population restoration viability analysis (PRVA) case studies of

Fetal growth trajectory and risk for eczema in a Saudi population.

Science.gov (United States)

AlMakoshi, Amel; Ellahi, Awaiss; Sallout, Bala; Devereux, Graham; Turner, Steve

2015-12-01

Recent studies in Western cohorts have identified associations between increasing fetal abdominal circumference (AC) during mid-pregnancy and increased risk for eczema and atopy. We sought to replicate these findings in a Saudi population where antenatal environmental exposures are different compared with Western countries. A Saudi birth cohort was recruited to relate maternal dietary intake and fetal growth to wheeze, eczema, and rhinitis in the first 2 yrs. Fetal size was determined from routine ultrasound scan measurements in the second and third trimesters and birthweight was noted. Parent-reported outcomes during the first 2 yrs were acquired by telephone-administered questionnaire. There were 1076 mothers recruited. AC was determined in 562 for the second, in 632 for the third, and in 281 for both second and third trimesters. A history of eczema was determined in 814 children at 2 yrs of age. There was an inverse relationship between change in abdominal circumference between the second and third trimesters for eczema (OR 0.66 per z score increase in AC [95% CI 0.49, 0.89]), and the quartile with the greatest faltering growth were at increased risk compared with other groups (p ≤ 0.045). Change in fetal size between the third trimester and birth was not associated with altered eczema risk. There were no associations between fetal growth and wheeze at the age of 2 yrs. Our findings contrast observations made in Western populations but nonetheless suggest that factors associated with changing fetal growth trajectory in the second half of pregnancy are also relevant to atopy development on the global setting. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Dynamics of individual growth in a recovering population of lake trout (Salvelinus namaycush)

Science.gov (United States)

Fabrizio, Mary C.; Dorazio, Robert M.; Schram, Stephen T.

2001-01-01

In 1976, the Wisconsin Department of Natural Resources established a refuge for a nearly depleted population of lake trout (Salvelinus namaycush) at Gull Island Shoal, Lake Superior. The refuge was intended to reduce fishing mortality by protecting adult lake trout. We examined the growth dynamics of these lake trout during the period of recovery by comparing estimates of ndividual growth before and after the refuge was established. Our estimates are based on an annual mark-recapture survey conducted at the spawning area since 1969. We developed a model that allowed mean growth rates to differ among individuals of different sizes and that accommodated variation in growth rates of individuals of the same size. Likelihood ratio tests were used to determine if the mean growth increments of lake trout changed ater the refuge was established. Our results suggest that growth of mature lake trout (particularly wild fish) decreased significantly in the postrefuge period. This decreased growth may have been associated with a reduction in food availability. We also observed reductions in growth as wild fish grew older and larger, which suggests that the growth of these fish may be adequately approximated by a von Bertalanffy growth model if it becomes possible to obtain accurate ages.

Modeling population dynamics and economic growth as competing species. An application to CO2 global emissions

International Nuclear Information System (INIS)

Puliafito, Salvador Enrique; Puliafito, Jose Luis; Grand, Mariana Conte

2008-01-01

Since the beginning of the last century the world is experiencing an important demographic transition, which will probably impact on economic growth. Many demographers and social scientists are trying to understand the key drivers of such transition as well as its profound implications. A correct understanding will help to predict other important trends of the world primary energy demand and the carbon emission to the atmosphere, which may be leading to an important climate change. This paper proposes a set of coupled differential equations to describe the changes of population, gross domestic product, primary energy consumption and carbon emissions, modeled as competing species as in Lotka-Volterra prey-predator relations. The predator-prey model is well known in the biological, ecological and environmental literature and has also been applied successfully in other fields. This model proposes a new and simple conceptual explanation of the interactions and feedbacks among the principal driving forces leading to the present transition. The estimated results for the temporal evolution of world population, gross domestic product, primary energy consumption and carbon emissions are calculated from year 1850 to year 2150. The calculated scenarios are in good agreement with common world data and projections for the next 100 years. (author)

Integrating physiological and biomechanical drivers of population growth over environmental gradients on coral reefs.

Science.gov (United States)

Madin, Joshua S; Hoogenboom, Mia O; Connolly, Sean R

2012-03-15

Coral reefs exhibit marked spatial and temporal variability, and coral reef organisms exhibit trade-offs in functional traits that influence demographic performance under different combinations of abiotic environmental conditions. In many systems, trait trade-offs are modelled using an energy and/or nutrient allocation framework. However, on coral reefs, differences in biomechanical vulnerability have major demographic implications, and indeed are believed to play an essential role in mediating species coexistence because highly competitive growth forms are vulnerable to physical dislodgment events that occur with high frequency (e.g. annual summer storms). Therefore, an integrated energy allocation and biomechanics framework is required to understand the effect of physical environmental gradients on species' demographic performance. However, on coral reefs, as in most ecosystems, the effects of environmental conditions on organisms are measured in different currencies (e.g. lipid accumulation, survival and number of gametes), and thus the relative contributions of these effects to overall capacity for population growth are not readily apparent. A comprehensive assessment of links between the environment and the organism, including those mediated by biomechanical processes, must convert environmental effects on individual-level performance (e.g. survival, growth and reproduction) into a common currency that is relevant to the capacity to contribute to population growth. We outline such an approach by considering the population-level performance of scleractinian reef corals over a hydrodynamic gradient, with a focus on the integrating the biomechanical determinants of size-dependent coral colony dislodgment as a function of flow, with the effects of flow on photosynthetic energy acquisition and respiration.

REGIONAL COMPONENTS OF GROWTH THE QUALITY OF LIFE OF THE POPULATION (FOR EXAMPLE, VORONEZH REGION

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N. A. Serebryakova

2015-01-01

Full Text Available At the present stage of development of economy there is a transformation of main objectives of the state from ensuring growth of welfare of citizens to ensuring continuous growth of quality of life. Ensuring growth of quality of life of the population is carried out not only on state, but also on regional levels. At the state level key tasks are formed, the state assumes a considerable share of functions on achievement of the designated purpose. In the real research the attention to consideration of the program documents directed on improvement of quality of life of the population on the example of the Voronezh region is paid. The program documents of a social orientation existing in the region are for this purpose studied. It is revealed that in the region a number of the programs and subprogrammes aimed at improvement of a demographic situation, improvement of a regional budgetary and tax policy, social support of citizens in general works. As tools which use regional authorities, are noted: social standards, address social help, social contracts. It is established that introduction of system of social contracts allows to save budget funds and, at the same time, to motivate the persons which are in a difficult life situation on change of the situation to the best, joint efforts with social security authorities. It is noted that as the leading principles of rendering the social help paramount value has detailed definition of degree of need of the help and a condition of granting. The last often generate dependant moods which are important for leveling, using levers of social interaction. The analysis of the contents of the realized programs for improvement of quality of life of the population allowed to reveal advantages and defects in these programs, and also to define reserves of growth of quality of life. So, it is specified that program documents of regional level in the prevailing majority have a narrow focus on ensuring the help and

Population growth, economic development and carrying capacity of the environment - are they compatible or in conflict?

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A. E. F. Heydom

1996-07-01

Full Text Available In South Africa, as in many other countries, human population growth is currently reaching levels which render competition for basic human needs such as land and water, inevitable. Concurrent to population growth is the absolute necessity for economic development and job opportunities which, in turn, make tremendous demands upon the environment and natural resource base. As a consequence ever greater emphasis is placed by the news media on apparent conflicts between industrial development and social needs on the one hand, and conservation of the environment and natural resources on the other.

Vegetation growth patterns on six rock-covered UMTRA Project disposal cells

International Nuclear Information System (INIS)

1992-02-01

This study assessed vegetation growth patterns, the potential impacts of vegetation growth on disposal cell cover integrity, and possible measures that could be taken to monitor and/or control plant growth, where necessary, on six Uranium Mill Tailings Remedial Action (UMTRA) Project rock-covered disposal cells. A large-scale invasion of volunteer plants was observed on the Shiprock and Burrell disposal cells. Plant growth at the South Clive, Green River, and Tuba City disposal cells was sparse except for the south rock apron and south slope of the Tuba City disposal cell, where windblown sand had filled up part of the rock cover and plant growth was observed. The rock-covered topslope of the Collins Ranch disposal cell was intentionally covered with topsoil and vegetated. Plant roots growing on the disposal cells are changing the characteristics of the cover by drying out the radon barrier, encouraging the establishment of soil-building processes in the bedding and radon barrier layers, creating channels in the radon barrier, and facilitating ecological succession, which could lead to the establishment of additional deep-rooted plants on the disposal cells. If left unchecked, plant roots would reach the tailings at the Burrell and Collins Ranch disposal cells within a few years, likely resulting in the transport of contaminants out of the cells

[The impact of population growth on Tamba Kosi, a Himalayan valley in Nepal].

Science.gov (United States)

Verliat, S

1994-01-01

Two several-month-long stays in the isolated Tamba Kosi valley in Nepal in 1983 and 1986 allowed an assessment of the importance of changes in rural societies. In about 50 years, the oldest inhabitants of some villages have seen the number of houses quadruple. In the absence of reliable statistical data, the inhabitants say that the Tamba Kosi valley population has doubled in the last 25 years. This population growth exacerbates the multiethnic fight for good land (i.e., ground of modest slope, hot, and humid). Many people have emigrated, which has somewhat eased problems relative to population growth. Soil degradation, which is becoming more and more acute, drives the inhabitants to cut down trees and clear the land for cultivation of new plots. These new plots are running up against steep slopes and high altitude. Most families have barely two hectares, which must suffice to feed 5-6 people on average. This fuels intensification of agricultural production, resulting in low efficacy. Livestock mutilate forests with their hooves and teeth. The marked increase in the variety of livestock accelerates this destruction. Three types of building materials are used in this high valley: thatch, shingles (fir tree), and bamboo matting. The disappearance of wild grasses used to make thatch roofs and people moving to higher and higher altitudes resulted in use of shingles to make roofs. Buildings made of shingles, which demanded changes in construction techniques, changed the conception of homes. They became the preferred building type, which increased the demand for fir trees and deforestation. This lead to a demand for roofing material made of bamboo matting and another change in construction techniques. The retreat of the forest and disappearance of the most wanted plant species are the most spectacular impacts of population growth. This environmental degradation exacerbates erosion at all bioclimatic altitudes.

Nutritional status and growth of children on macrobiotic diets : a population-based study

NARCIS (Netherlands)

Dagnelie, P.C.

1988-01-01

This thesis reports on the relationship between diet, growth, blood chemistry, psychomotor development, and clinical findings in the Dutch population of children on macrobiotic diets.- The macrobiotic diet mainly consisted of cereals, pulses and vegetables with small additions of seaweeds,

Understanding Underrepresented Populations in the Business School Pipeline. GMAC® Research Report RR-16-02

Science.gov (United States)

Daniel, Rhonda; Caruthers, Devina

2016-01-01

This white paper, "Understanding Underrepresented Populations in the Business School Pipeline," examines the shifting US racial and ethnic demographics and projected growth among US minority populations and the challenges--and incentives--these developments pose for US business schools to increase the opportunities for minority students…

Density-independent population projection trajectories of chromosome-substituted lines resistant and susceptible to organophosphate insecticides in Drosophila melanogaster

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Miyo Takahiro

2004-11-01

Full Text Available Abstract Background Seasonal fluctuations in susceptibility to organophosphate insecticides were observed in the Katsunuma population of Drosophila melanogaster for two consecutive years; susceptibility to three organophosphates tended to increase in the fall. To examine the hypothesis that variation in fitness among resistant and susceptible genotypes could trigger the change of genetic constitution within the fall population, we investigated density-independent population projection trajectories starting from single adult females with characteristics of chromosome-substituted lines resistant and susceptible to the three organophosphates. Results Density-independent population projection trajectories, expressed as the ratios of the number of each chromosome-substituted line to that of line SSS, for which all chromosomes were derived from the susceptible line, showed significant declines in numbers with time for all the resistant chromosome-substituted lines. Conclusion The declining tendency in the density-independent population projection trajectories of the resistant chromosome-substituted lines could explain the simultaneous decline in the levels of resistance to the three organophosphates, observed in the Katsunuma population in the fall.