Predicting long-term graft survival in adult kidney transplant recipients.

PubMed

Pinsky, Brett W; Lentine, Krista L; Ercole, Patrick R; Salvalaggio, Paolo R; Burroughs, Thomas E; Schnitzler, Mark A

2012-07-01

The ability to accurately predict a population's long-term survival has important implications for quantifying the benefits of transplantation. To identify a model that can accurately predict a kidney transplant population's long-term graft survival, we retrospectively studied the United Network of Organ Sharing data from 13,111 kidney-only transplants completed in 1988- 1989. Nineteen-year death-censored graft survival (DCGS) projections were calculated and compared with the population's actual graft survival. The projection curves were created using a two-part estimation model that (1) fits a Kaplan-Meier survival curve immediately after transplant (Part A) and (2) uses truncated observational data to model a survival function for long-term projection (Part B). Projection curves were examined using varying amounts of time to fit both parts of the model. The accuracy of the projection curve was determined by examining whether predicted survival fell within the 95% confidence interval for the 19-year Kaplan-Meier survival, and the sample size needed to detect the difference in projected versus observed survival in a clinical trial. The 19-year DCGS was 40.7% (39.8-41.6%). Excellent predictability (41.3%) can be achieved when Part A is fit for three years and Part B is projected using two additional years of data. Using less than five total years of data tended to overestimate the population's long-term survival, accurate prediction of long-term DCGS is possible, but requires attention to the quantity data used in the projection method.

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

USGS Publications Warehouse

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.

Does Specification Matter? Experiments with Simple Multiregional Probabilistic Population Projections

PubMed Central

Raymer, James; Abel, Guy J.; Rogers, Andrei

2012-01-01

Population projection models that introduce uncertainty are a growing subset of projection models in general. In this paper, we focus on the importance of decisions made with regard to the model specifications adopted. We compare the forecasts and prediction intervals associated with four simple regional population projection models: an overall growth rate model, a component model with net migration, a component model with in-migration and out-migration rates, and a multiregional model with destination-specific out-migration rates. Vector autoregressive models are used to forecast future rates of growth, birth, death, net migration, in-migration and out-migration, and destination-specific out-migration for the North, Midlands and South regions in England. They are also used to forecast different international migration measures. The base data represent a time series of annual data provided by the Office for National Statistics from 1976 to 2008. The results illustrate how both the forecasted subpopulation totals and the corresponding prediction intervals differ for the multiregional model in comparison to other simpler models, as well as for different assumptions about international migration. The paper ends end with a discussion of our results and possible directions for future research. PMID:23236221

Small area population forecasting: some experience with British models.

PubMed

Openshaw, S; Van Der Knaap, G A

1983-01-01

This study is concerned with the evaluation of the various models including time-series forecasts, extrapolation, and projection procedures, that have been developed to prepare population forecasts for planning purposes. These models are evaluated using data for the Netherlands. "As part of a research project at the Erasmus University, space-time population data has been assembled in a geographically consistent way for the period 1950-1979. These population time series are of sufficient length for the first 20 years to be used to build models and then evaluate the performance of the model for the next 10 years. Some 154 different forecasting models for 832 municipalities have been evaluated. It would appear that the best forecasts are likely to be provided by either a Holt-Winters model, or a ratio-correction model, or a low order exponential-smoothing model." excerpt

Organism and population-level ecological models for ...

EPA Pesticide Factsheets

Ecological risk assessment typically focuses on animal populations as endpoints for regulatory ecotoxicology. Scientists at USEPA are developing models for animal populations exposed to a wide range of chemicals from pesticides to emerging contaminants. Modeled taxa include aquatic and terrestrial invertebrates, fish, amphibians, and birds, and employ a wide range of methods, from matrix-based projection models to mechanistic bioenergetics models and spatially explicit population models. not applicable

Assessing the Energy and Emissions Implications of Alternative Population Scenarios Using a State-Level Integrated Assessment Model

EPA Science Inventory

We use GCAM-USA to examine the sensitivity of energy demands and resulting pollutant emissions and health impacts to differing population projections. The population projections are based on future fertility, mortality, migration and education assumptions consistent with the five...

Projection of the year 2050 burden of diabetes in the US adult population: dynamic modeling of incidence, mortality, and prediabetes prevalence

PubMed Central

2010-01-01

Background People with diabetes can suffer from diverse complications that seriously erode quality of life. Diabetes, costing the United States more than $174 billion per year in 2007, is expected to take an increasingly large financial toll in subsequent years. Accurate projections of diabetes burden are essential to policymakers planning for future health care needs and costs. Methods Using data on prediabetes and diabetes prevalence in the United States, forecasted incidence, and current US Census projections of mortality and migration, the authors constructed a series of dynamic models employing systems of difference equations to project the future burden of diabetes among US adults. A three-state model partitions the US population into no diabetes, undiagnosed diabetes, and diagnosed diabetes. A four-state model divides the state of "no diabetes" into high-risk (prediabetes) and low-risk (normal glucose) states. A five-state model incorporates an intervention designed to prevent or delay diabetes in adults at high risk. Results The authors project that annual diagnosed diabetes incidence (new cases) will increase from about 8 cases per 1,000 in 2008 to about 15 in 2050. Assuming low incidence and relatively high diabetes mortality, total diabetes prevalence (diagnosed and undiagnosed cases) is projected to increase from 14% in 2010 to 21% of the US adult population by 2050. However, if recent increases in diabetes incidence continue and diabetes mortality is relatively low, prevalence will increase to 33% by 2050. A middle-ground scenario projects a prevalence of 25% to 28% by 2050. Intervention can reduce, but not eliminate, increases in diabetes prevalence. Conclusions These projected increases are largely attributable to the aging of the US population, increasing numbers of members of higher-risk minority groups in the population, and people with diabetes living longer. Effective strategies will need to be undertaken to moderate the impact of these factors on national diabetes burden. Our analysis suggests that widespread implementation of reasonably effective preventive interventions focused on high-risk subgroups of the population can considerably reduce, but not eliminate, future increases in diabetes prevalence. PMID:20969750

bayesPop: Probabilistic Population Projections

PubMed Central

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

Report B: 1986 projected population, labor force and unemployment - Delaware

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

1985-09-01

Report B, the results of the Population, Labor Force and Unemployment Projections Model, contain current socio-economic indicators. For each geographic area, there is one page of summary/background information followed by three tables. These tables contain the population projections, the labor force projections, and the unemployment projections, respectively. These tables are composed of data for the following racial groups: total population, whites, blacks, and other races. Those who call themselves Hispanics may be covered in any of the last three racial groups. For those geographic areas which have provided more than one labor force and/or unemployment control total, the last twomore » tables will appear more than once.« less

A Theoretical Math Model for Projecting AIS3+ Thoracic Injury for Belted Occupants in Frontal Impact.

PubMed

Laituri, Tony R; Sullivan, Donald; Sullivan, Kaye; Prasad, Priya

2004-11-01

A theoretical math model was created to assess the net effect of aging populations versus evolving system designs from the standpoint of thoracic injury potential. The model was used to project the next twenty-five years of thoracic injuries in Canada. The choice of Canada was topical because rulemaking for CMVSS 208 has been proposed recently. The study was limited to properly-belted, front-outboard, adult occupants in 11-1 o'clock frontal crashes. Moreover, only AIS3+ thoracic injury potential was considered. The research consisted of four steps. First, sub-models were developed and integrated. The sub-models were made for numerous real-world effects including population growth, crash involvement, fleet penetration of various systems (via system introduction, vehicle production, and vehicle attrition), and attendant injury risk estimation. Second, existing NASS data were used to estimate the number of AIS3+ chest-injured drivers in Canada in 2001. This served as data for model validation. Third, the projection model was correlated favorably with the 2001 field estimate. Finally, for the scenario that 2004-2030 model-year systems would perform like 2000-2003 model-year systems, a projection was made to estimate the long-term effect of eliminating designs that would not comply with the proposed CMVSS 208. The 2006-2030-projection result for this scenario: 764 occupants would benefit from the proposed regulation. This projection was considered to be conservative because future innovation was not considered, and, to date, the fleet's average chest deflections have been decreasing. The model also predicted that, through 2016, the effect of improving system performance would be more influential than the population-aging effect; thereafter, the population-aging effect would somewhat counteract the effect of improving system performance. This theoretical math model can provide insights for both designers and rule makers.

Global asymptotic stability of density dependent integral population projection models.

PubMed

Rebarber, Richard; Tenhumberg, Brigitte; Townley, Stuart

2012-02-01

Many stage-structured density dependent populations with a continuum of stages can be naturally modeled using nonlinear integral projection models. In this paper, we study a trichotomy of global stability result for a class of density dependent systems which include a Platte thistle model. Specifically, we identify those systems parameters for which zero is globally asymptotically stable, parameters for which there is a positive asymptotically stable equilibrium, and parameters for which there is no asymptotically stable equilibrium. Copyright © 2011 Elsevier Inc. All rights reserved.

Climate change threatens polar bear populations: a stochastic demographic analysis.

PubMed

Hunter, Christine M; Caswell, Hal; Runge, Michael C; Regehr, Eric V; Amstrup, Steve C; Stirling, Ian

2010-10-01

The polar bear (Ursus maritimus) depends on sea ice for feeding, breeding, and movement. Significant reductions in Arctic sea ice are forecast to continue because of climate warming. We evaluated the impacts of climate change on polar bears in the southern Beaufort Sea by means of a demographic analysis, combining deterministic, stochastic, environment-dependent matrix population models with forecasts of future sea ice conditions from IPCC general circulation models (GCMs). The matrix population models classified individuals by age and breeding status; mothers and dependent cubs were treated as units. Parameter estimates were obtained from a capture-recapture study conducted from 2001 to 2006. Candidate statistical models allowed vital rates to vary with time and as functions of a sea ice covariate. Model averaging was used to produce the vital rate estimates, and a parametric bootstrap procedure was used to quantify model selection and parameter estimation uncertainty. Deterministic models projected population growth in years with more extensive ice coverage (2001-2003) and population decline in years with less ice coverage (2004-2005). LTRE (life table response experiment) analysis showed that the reduction in lambda in years with low sea ice was due primarily to reduced adult female survival, and secondarily to reduced breeding. A stochastic model with two environmental states, good and poor sea ice conditions, projected a declining stochastic growth rate, log lambdas, as the frequency of poor ice years increased. The observed frequency of poor ice years since 1979 would imply log lambdas approximately - 0.01, which agrees with available (albeit crude) observations of population size. The stochastic model was linked to a set of 10 GCMs compiled by the IPCC; the models were chosen for their ability to reproduce historical observations of sea ice and were forced with "business as usual" (A1B) greenhouse gas emissions. The resulting stochastic population projections showed drastic declines in the polar bear population by the end of the 21st century. These projections were instrumental in the decision to list the polar bear as a threatened species under the U.S. Endangered Species Act.

Climate change threatens polar bear populations: A stochastic demographic analysis

USGS Publications Warehouse

Hunter, C.M.; Caswell, H.; Runge, M.C.; Regehr, E.V.; Amstrup, Steven C.; Stirling, I.

2010-01-01

The polar bear (Ursus maritimus) depends on sea ice for feeding, breeding, and movement. Significant reductions in Arctic sea ice are forecast to continue because of climate warming. We evaluated the impacts of climate change on polar bears in the southern Beaufort Sea by means of a demographic analysis, combining deterministic, stochastic, environment-dependent matrix population models with forecasts of future sea ice conditions from IPCC general circulation models (GCMs). The matrix population models classified individuals by age and breeding status; mothers and dependent cubs were treated as units. Parameter estimates were obtained from a capture-recapture study conducted from 2001 to 2006. Candidate statistical models allowed vital rates to vary with time and as functions of a sea ice covariate. Model averaging was used to produce the vital rate estimates, and a parametric bootstrap procedure was used to quantify model selection and parameter estimation uncertainty. Deterministic models projected population growth in years with more extensive ice coverage (2001-2003) and population decline in years with less ice coverage (2004-2005). LTRE (life table response experiment) analysis showed that the reduction in ?? in years with low sea ice was due primarily to reduced adult female survival, and secondarily to reduced breeding. A stochastic model with two environmental states, good and poor sea ice conditions, projected a declining stochastic growth rate, log ??s, as the frequency of poor ice years increased. The observed frequency of poor ice years since 1979 would imply log ??s ' - 0.01, which agrees with available (albeit crude) observations of population size. The stochastic model was linked to a set of 10 GCMs compiled by the IPCC; the models were chosen for their ability to reproduce historical observations of sea ice and were forced with "business as usual" (A1B) greenhouse gas emissions. The resulting stochastic population projections showed drastic declines in the polar bear population by the end of the 21st century. These projections were instrumental in the decision to list the polar bear as a threatened species under the U.S. Endangered Species Act. ?? 2010 by the Ecological Society of America.

Projected impact of urbanization on cardiovascular disease in China.

PubMed

Chan, Faye; Adamo, Susana; Coxson, Pamela; Goldman, Lee; Gu, Dongfeng; Zhao, Dong; Chen, Chung-Shiuan; He, Jiang; Mara, Valentina; Moran, Andrew

2012-10-01

The Coronary Heart Disease (CHD) Policy Model-China, a national scale cardiovascular disease computer simulation model, was used to project future impact of urbanization. Populations and cardiovascular disease incidence rates were stratified into four submodels: North-Urban, South-Urban, North-Rural, and South-Rural. 2010 was the base year, and high and low urbanization rate scenarios were used to project 2030 populations. Rural-to-urban migration, population growth, and aging were projected to more than double cardiovascular disease events in urban areas and increase events by 27.0-45.6% in rural areas. Urbanization is estimated to raise age-standardized coronary heart disease incidence by 73-81 per 100,000 and stroke incidence only slightly. Rural-to-urban migration will likely be a major demographic driver of the cardiovascular disease epidemic in China.

Assessing the Energy and Emissions Implications of Alternative Population Scenarios Using a State-Level Integrated Assessment Model

NASA Astrophysics Data System (ADS)

Shi, W.; Nolte, C. G.; Loughlin, D. H.; Ou, Y.; Smith, S. J.

2017-12-01

We use GCAM-USA to examine the sensitivity of energy demands and resulting pollutant emissions and health impacts to differing population projections. The population projections are based on future fertility, mortality, migration and education assumptions consistent with the five Shared Socioeconomic Pathways (SSPs) (Jones and O'Neill, 2016). By using a state-level integrated assessment model, we capture the energy and emissions implications of population changes. Additionally, we overlay heating degree days and cooling degree days calculated from climate change projections to assess the individual and combined impacts of population shifts and climate change. A unique aspect of this work is the explicit representation of important regulatory drivers, such as the Cross-State Air Pollution Rule and vehicle efficiency standards. Preliminary results indicate there are significant differences across population scenarios in both U.S. national and state-level emissions. In this presentation, we will examine the influence of underlying factors such as climate, population, and technology changes on emissions and environmental impacts at 2050.

The PEDA Model. An advocacy tool modeling the interrelationships between population, development, the environment and agriculture in Africa.

PubMed

1999-01-01

This article reports on the PEDA (population changes, environment, socioeconomic development and agriculture) model and its implication for policy-making in Africa. PEDA is an interactive computer simulation model (developed for a Windows environment) demonstrating the long-term impacts of alternative national policies on food security status of the population. The model is based on multistate demographic techniques, projecting at the same time 8 different subgroups (by age and sex) in the population, and based on 3 dichotomous individual characteristics: urban/rural place of residence; literacy status; and food security status. Through the manipulation of scenario variables, the model enables the user to project the proportion of the population that will be food secure and food insecure for a chosen point in time. This model developed by Dr. W. Lutz, Director of the International Institute for Applied Systems Analysis, will serve as an advocacy tool to help convince policy-makers and country experts in Africa of the negative synergy arising from the interconnections of population growth, environmental deterioration, and declining agricultural production.

Analysis of urban-rural population dynamics for China.

PubMed

Shen, J

1991-12-01

The population dynamics of China are presented in a multiregional demographic model using regional estimates or mortality and migration based on the 1% population sample survey in 1987. An open ended population account is generated for period cohort a, gender g of region i (urban) and j (rural) using population, birth, death, and migration. Demographic rates and equations for flows of nonsurviving migrants of period cohort a of gender g are estimated using the forward demographic rate definition. Out-migration rates for period cohort a of gender g are defined by migration flow divided by the initial population. The death rate for period cohort A1 and A are estimated using a single region method. Death and migration rates are simultaneously estimated with an iterative procedure. The population accounts estimates and demographic rates are provided for the period ending 1986-87 for male births, males in period cohorts 10 and 20, female births, and females in period cohorts 10 and 20. The urban and rural population projection model is based on the population accounts concept and assumes fixed rates of mortality, migration, and normal fertility for the base year 1987. The results of this projection are a population of 1090 million that will grow to 1304 million in 2000, 1720 million in 2050, and 1791 million in 2087. Urban population will expand from 44.2% in 1988 to 46.6% in 2000, and 54.7% in 2087. The labor population of males 18-65 years and females 18-60 years will increase from 58.8% in 1988 to 59.7% in 2000 and decline to 58.4% by 2087. The old age population of males 65 years and females 60 years will increase from 6.5% in 1988 to 7.9% in 2000, and 16.3% in 2087. The mean age increased from 28.3 years in 1988 to 37 in 2087. Urban population may be underprojected; migration problems are recognized. Fertility also is likely to decline. An alternative projection (B) is given to account for the U-shape distribution and urban fertility of 1.8 in 2000, increasing to and stabilizing at 2.2 in 2020, such that population estimates for 2000 are 1291 and 1524 for 2087 with a peak in 2048 of 1573. A faster fertility decline is also used to generate projection C. The author's projections A, B, and C, which are based on more recent data and a more realistic model, are than the "objective projection" and than the "warning projection" generated by China's Population Census Office based on 1982 census data.

Coupled Flip-Flop Model for REM Sleep Regulation in the Rat

PubMed Central

Dunmyre, Justin R.; Mashour, George A.; Booth, Victoria

2014-01-01

Recent experimental studies investigating the neuronal regulation of rapid eye movement (REM) sleep have identified mutually inhibitory synaptic projections among REM sleep-promoting (REM-on) and REM sleep-inhibiting (REM-off) neuronal populations that act to maintain the REM sleep state and control its onset and offset. The control mechanism of mutually inhibitory synaptic interactions mirrors the proposed flip-flop switch for sleep-wake regulation consisting of mutually inhibitory synaptic projections between wake- and sleep-promoting neuronal populations. While a number of synaptic projections have been identified between these REM-on/REM-off populations and wake/sleep-promoting populations, the specific interactions that govern behavioral state transitions have not been completely determined. Using a minimal mathematical model, we investigated behavioral state transition dynamics dictated by a system of coupled flip-flops, one to control transitions between wake and sleep states, and another to control transitions into and out of REM sleep. The model describes the neurotransmitter-mediated inhibitory interactions between a wake- and sleep-promoting population, and between a REM-on and REM-off population. We proposed interactions between the wake/sleep and REM-on/REM-off flip-flops to replicate the behavioral state statistics and probabilities of behavioral state transitions measured from experimental recordings of rat sleep under ad libitum conditions and after 24 h of REM sleep deprivation. Reliable transitions from REM sleep to wake, as dictated by the data, indicated the necessity of an excitatory projection from the REM-on population to the wake-promoting population. To replicate the increase in REM-wake-REM transitions observed after 24 h REM sleep deprivation required that this excitatory projection promote transient activation of the wake-promoting population. Obtaining the reliable wake-nonREM sleep transitions observed in the data required that activity of the wake-promoting population modulated the interaction between the REM-on and REM-off populations. This analysis suggests neuronal processes to be targeted in further experimental studies of the regulatory mechanisms of REM sleep. PMID:24722577

Coupled flip-flop model for REM sleep regulation in the rat.

PubMed

Dunmyre, Justin R; Mashour, George A; Booth, Victoria

2014-01-01

Recent experimental studies investigating the neuronal regulation of rapid eye movement (REM) sleep have identified mutually inhibitory synaptic projections among REM sleep-promoting (REM-on) and REM sleep-inhibiting (REM-off) neuronal populations that act to maintain the REM sleep state and control its onset and offset. The control mechanism of mutually inhibitory synaptic interactions mirrors the proposed flip-flop switch for sleep-wake regulation consisting of mutually inhibitory synaptic projections between wake- and sleep-promoting neuronal populations. While a number of synaptic projections have been identified between these REM-on/REM-off populations and wake/sleep-promoting populations, the specific interactions that govern behavioral state transitions have not been completely determined. Using a minimal mathematical model, we investigated behavioral state transition dynamics dictated by a system of coupled flip-flops, one to control transitions between wake and sleep states, and another to control transitions into and out of REM sleep. The model describes the neurotransmitter-mediated inhibitory interactions between a wake- and sleep-promoting population, and between a REM-on and REM-off population. We proposed interactions between the wake/sleep and REM-on/REM-off flip-flops to replicate the behavioral state statistics and probabilities of behavioral state transitions measured from experimental recordings of rat sleep under ad libitum conditions and after 24 h of REM sleep deprivation. Reliable transitions from REM sleep to wake, as dictated by the data, indicated the necessity of an excitatory projection from the REM-on population to the wake-promoting population. To replicate the increase in REM-wake-REM transitions observed after 24 h REM sleep deprivation required that this excitatory projection promote transient activation of the wake-promoting population. Obtaining the reliable wake-nonREM sleep transitions observed in the data required that activity of the wake-promoting population modulated the interaction between the REM-on and REM-off populations. This analysis suggests neuronal processes to be targeted in further experimental studies of the regulatory mechanisms of REM sleep.

Comparison of reintroduction and enhancement effects on metapopulation viability

USGS Publications Warehouse

Halsey, Samniqueka J; Bell, Timothy J.; McEachern, A. Kathryn; Pavlovic, Noel B.

2015-01-01

Metapopulation viability depends upon a balance of extinction and colonization of local habitats by a species. Mechanisms that can affect this balance include physical characteristics related to natural processes (e.g. succession) as well as anthropogenic actions. Plant restorations can help to produce favorable metapopulation dynamics and consequently increase viability; however, to date no studies confirm this is true. Population viability analysis (PVA) allows for the use of empirical data to generate theoretical future projections in the form of median time to extinction and probability of extinction. In turn, PVAs can inform and aid the development of conservation, recovery, and management plans. Pitcher's thistle (Cirsium pitcheri) is a dune endemic that exhibited metapopulation dynamics. We projected viability of three natural and two restored populations with demographic data spanning 15–23 years to determine the degree the addition of reintroduced population affects metapopulation viability. The models were validated by comparing observed and projected abundances and adjusting parameters associated with demographic and environmental stochasticity to improve model performance. Our chosen model correctly predicted yearly population abundance for 60% of the population-years. Using that model, 50-year projections showed that the addition of reintroductions increases metapopulation viability. The reintroduction that simulated population performance in early-successional habitats had the maximum benefit. In situ enhancements of existing populations proved to be equally effective. This study shows that restorations can facilitate and improve metapopulation viability of species dependent on metapopulation dynamics for survival with long-term persistence of C. pitcheri in Indiana likely to depend on continued active management.

Bayesian probabilistic population projections for all countries.

PubMed

Raftery, Adrian E; Li, Nan; Ševčíková, Hana; Gerland, Patrick; Heilig, Gerhard K

2012-08-28

Projections of countries' future populations, broken down by age and sex, are widely used for planning and research. They are mostly done deterministically, but there is a widespread need for probabilistic projections. We propose a bayesian method for probabilistic population projections for all countries. The total fertility rate and female and male life expectancies at birth are projected probabilistically using bayesian hierarchical models estimated via Markov chain Monte Carlo using United Nations population data for all countries. These are then converted to age-specific rates and combined with a cohort component projection model. This yields probabilistic projections of any population quantity of interest. The method is illustrated for five countries of different demographic stages, continents and sizes. The method is validated by an out of sample experiment in which data from 1950-1990 are used for estimation, and applied to predict 1990-2010. The method appears reasonably accurate and well calibrated for this period. The results suggest that the current United Nations high and low variants greatly underestimate uncertainty about the number of oldest old from about 2050 and that they underestimate uncertainty for high fertility countries and overstate uncertainty for countries that have completed the demographic transition and whose fertility has started to recover towards replacement level, mostly in Europe. The results also indicate that the potential support ratio (persons aged 20-64 per person aged 65+) will almost certainly decline dramatically in most countries over the coming decades.

Impact of climate change on global malaria distribution.

PubMed

Caminade, Cyril; Kovats, Sari; Rocklov, Joacim; Tompkins, Adrian M; Morse, Andrew P; Colón-González, Felipe J; Stenlund, Hans; Martens, Pim; Lloyd, Simon J

2014-03-04

Malaria is an important disease that has a global distribution and significant health burden. The spatial limits of its distribution and seasonal activity are sensitive to climate factors, as well as the local capacity to control the disease. Malaria is also one of the few health outcomes that has been modeled by more than one research group and can therefore facilitate the first model intercomparison for health impacts under a future with climate change. We used bias-corrected temperature and rainfall simulations from the Coupled Model Intercomparison Project Phase 5 climate models to compare the metrics of five statistical and dynamical malaria impact models for three future time periods (2030s, 2050s, and 2080s). We evaluated three malaria outcome metrics at global and regional levels: climate suitability, additional population at risk and additional person-months at risk across the model outputs. The malaria projections were based on five different global climate models, each run under four emission scenarios (Representative Concentration Pathways, RCPs) and a single population projection. We also investigated the modeling uncertainty associated with future projections of populations at risk for malaria owing to climate change. Our findings show an overall global net increase in climate suitability and a net increase in the population at risk, but with large uncertainties. The model outputs indicate a net increase in the annual person-months at risk when comparing from RCP2.6 to RCP8.5 from the 2050s to the 2080s. The malaria outcome metrics were highly sensitive to the choice of malaria impact model, especially over the epidemic fringes of the malaria distribution.

Impact of climate change on global malaria distribution

PubMed Central

Caminade, Cyril; Kovats, Sari; Rocklov, Joacim; Tompkins, Adrian M.; Morse, Andrew P.; Colón-González, Felipe J.; Stenlund, Hans; Martens, Pim; Lloyd, Simon J.

2014-01-01

Malaria is an important disease that has a global distribution and significant health burden. The spatial limits of its distribution and seasonal activity are sensitive to climate factors, as well as the local capacity to control the disease. Malaria is also one of the few health outcomes that has been modeled by more than one research group and can therefore facilitate the first model intercomparison for health impacts under a future with climate change. We used bias-corrected temperature and rainfall simulations from the Coupled Model Intercomparison Project Phase 5 climate models to compare the metrics of five statistical and dynamical malaria impact models for three future time periods (2030s, 2050s, and 2080s). We evaluated three malaria outcome metrics at global and regional levels: climate suitability, additional population at risk and additional person-months at risk across the model outputs. The malaria projections were based on five different global climate models, each run under four emission scenarios (Representative Concentration Pathways, RCPs) and a single population projection. We also investigated the modeling uncertainty associated with future projections of populations at risk for malaria owing to climate change. Our findings show an overall global net increase in climate suitability and a net increase in the population at risk, but with large uncertainties. The model outputs indicate a net increase in the annual person-months at risk when comparing from RCP2.6 to RCP8.5 from the 2050s to the 2080s. The malaria outcome metrics were highly sensitive to the choice of malaria impact model, especially over the epidemic fringes of the malaria distribution. PMID:24596427

EVALUATION OF THE EFFICACY OF EXTRAPOLATION POPULATION MODELING TO PREDICT THE DYNAMICS OF AMERICAMYSIS BAHIA POPULATIONS IN THE LABORATORY

EPA Science Inventory

An age-classified projection matrix model has been developed to extrapolate the chronic (28-35d) demographic responses of Americamysis bahia (formerly Mysidopsis bahia) to population-level response. This study was conducted to evaluate the efficacy of this model for predicting t...

Adaptation of water resource systems to an uncertain future

NASA Astrophysics Data System (ADS)

Walsh, C. L.; Blenkinsop, S.; Fowler, H. J.; Burton, A.; Dawson, R. J.; Glenis, V.; Manning, L. J.; Kilsby, C. G.

2015-09-01

Globally, water resources management faces significant challenges from changing climate and growing populations. At local scales, the information provided by climate models is insufficient to support the water sector in making future adaptation decisions. Furthermore, projections of change in local water resources are wrought with uncertainties surrounding natural variability, future greenhouse gas emissions, model structure, population growth and water consumption habits. To analyse the magnitude of these uncertainties, and their implications for local scale water resource planning, we present a top-down approach for testing climate change adaptation options using probabilistic climate scenarios and demand projections. An integrated modelling framework is developed which implements a new, gridded spatial weather generator, coupled with a rainfall-runoff model and water resource management simulation model. We use this to provide projections of the number of days, and associated uncertainty that will require implementation of demand saving measures such as hose pipe bans and drought orders. Results, which are demonstrated for the Thames basin, UK, indicate existing water supplies are sensitive to a changing climate and an increasing population, and that the frequency of severe demand saving measures are projected to increase. Considering both climate projections and population growth the median number of drought order occurrences may increase five-fold. The effectiveness of a range of demand management and supply options have been tested and shown to provide significant benefits in terms of reducing the number of demand saving days. We found that increased supply arising from various adaptation options may compensate for increasingly variable flows; however, without reductions in overall demand for water resources such options will be insufficient on their own to adapt to uncertainties in the projected changes in climate and population. For example, a 30 % reduction in overall demand by 2050 has a greater impact on reducing the frequency of drought orders than any of the individual or combinations of supply options; hence a portfolio of measures are required.

A framework for studying transient dynamics of population projection matrix models.

PubMed

Stott, Iain; Townley, Stuart; Hodgson, David James

2011-09-01

Empirical models are central to effective conservation and population management, and should be predictive of real-world dynamics. Available modelling methods are diverse, but analysis usually focuses on long-term dynamics that are unable to describe the complicated short-term time series that can arise even from simple models following ecological disturbances or perturbations. Recent interest in such transient dynamics has led to diverse methodologies for their quantification in density-independent, time-invariant population projection matrix (PPM) models, but the fragmented nature of this literature has stifled the widespread analysis of transients. We review the literature on transient analyses of linear PPM models and synthesise a coherent framework. We promote the use of standardised indices, and categorise indices according to their focus on either convergence times or transient population density, and on either transient bounds or case-specific transient dynamics. We use a large database of empirical PPM models to explore relationships between indices of transient dynamics. This analysis promotes the use of population inertia as a simple, versatile and informative predictor of transient population density, but criticises the utility of established indices of convergence times. Our findings should guide further development of analyses of transient population dynamics using PPMs or other empirical modelling techniques. © 2011 Blackwell Publishing Ltd/CNRS.

78 FR 43147 - Fisheries of the South Atlantic; Southeast Data, Assessment, and Review (SEDAR); Public Meetings

Federal Register 2010, 2011, 2012, 2013, 2014

2013-07-19

..., estimates biological benchmarks, projects future population conditions, and recommends research and... the Assessment webinars are as follows: 1. Participants will employ assessment models to evaluate stock status, estimate population benchmarks and management criteria, and project future conditions. The...

Simulated bat populations erode when exposed to climate change projections for western North America

PubMed Central

Adams, Rick A.

2017-01-01

Recent research has demonstrated that temperature and precipitation conditions correlate with successful reproduction in some insectivorous bat species that live in arid and semiarid regions, and that hot and dry conditions correlate with reduced lactation and reproductive output by females of some species. However, the potential long-term impacts of climate-induced reproductive declines on bat populations in western North America are not well understood. We combined results from long-term field monitoring and experiments in our study area with information on vital rates to develop stochastic age-structured population dynamics models and analyzed how simulated fringed myotis (Myotis thysanodes) populations changed under projected future climate conditions in our study area near Boulder, Colorado (Boulder Models) and throughout western North America (General Models). Each simulation consisted of an initial population of 2,000 females and an approximately stable age distribution at the beginning of the simulation. We allowed each population to be influenced by the mean annual temperature and annual precipitation for our study area and a generalized range-wide model projected through year 2086, for each of four carbon emission scenarios (representative concentration pathways RCP2.6, RCP4.5, RCP6.0, RCP8.5). Each population simulation was repeated 10,000 times. Of the 8 Boulder Model simulations, 1 increased (+29.10%), 3 stayed approximately stable (+2.45%, +0.05%, -0.03%), and 4 simulations decreased substantially (-44.10%, -44.70%, -44.95%, -78.85%). All General Model simulations for western North America decreased by >90% (-93.75%, -96.70%, -96.70%, -98.75%). These results suggest that a changing climate in western North America has the potential to quickly erode some forest bat populations including species of conservation concern, such as fringed myotis. PMID:28686737

Simulated bat populations erode when exposed to climate change projections for western North America.

PubMed

Hayes, Mark A; Adams, Rick A

2017-01-01

Recent research has demonstrated that temperature and precipitation conditions correlate with successful reproduction in some insectivorous bat species that live in arid and semiarid regions, and that hot and dry conditions correlate with reduced lactation and reproductive output by females of some species. However, the potential long-term impacts of climate-induced reproductive declines on bat populations in western North America are not well understood. We combined results from long-term field monitoring and experiments in our study area with information on vital rates to develop stochastic age-structured population dynamics models and analyzed how simulated fringed myotis (Myotis thysanodes) populations changed under projected future climate conditions in our study area near Boulder, Colorado (Boulder Models) and throughout western North America (General Models). Each simulation consisted of an initial population of 2,000 females and an approximately stable age distribution at the beginning of the simulation. We allowed each population to be influenced by the mean annual temperature and annual precipitation for our study area and a generalized range-wide model projected through year 2086, for each of four carbon emission scenarios (representative concentration pathways RCP2.6, RCP4.5, RCP6.0, RCP8.5). Each population simulation was repeated 10,000 times. Of the 8 Boulder Model simulations, 1 increased (+29.10%), 3 stayed approximately stable (+2.45%, +0.05%, -0.03%), and 4 simulations decreased substantially (-44.10%, -44.70%, -44.95%, -78.85%). All General Model simulations for western North America decreased by >90% (-93.75%, -96.70%, -96.70%, -98.75%). These results suggest that a changing climate in western North America has the potential to quickly erode some forest bat populations including species of conservation concern, such as fringed myotis.

Bayesian probabilistic population projections for all countries

PubMed Central

Raftery, Adrian E.; Li, Nan; Ševčíková, Hana; Gerland, Patrick; Heilig, Gerhard K.

2012-01-01

Projections of countries’ future populations, broken down by age and sex, are widely used for planning and research. They are mostly done deterministically, but there is a widespread need for probabilistic projections. We propose a Bayesian method for probabilistic population projections for all countries. The total fertility rate and female and male life expectancies at birth are projected probabilistically using Bayesian hierarchical models estimated via Markov chain Monte Carlo using United Nations population data for all countries. These are then converted to age-specific rates and combined with a cohort component projection model. This yields probabilistic projections of any population quantity of interest. The method is illustrated for five countries of different demographic stages, continents and sizes. The method is validated by an out of sample experiment in which data from 1950–1990 are used for estimation, and applied to predict 1990–2010. The method appears reasonably accurate and well calibrated for this period. The results suggest that the current United Nations high and low variants greatly underestimate uncertainty about the number of oldest old from about 2050 and that they underestimate uncertainty for high fertility countries and overstate uncertainty for countries that have completed the demographic transition and whose fertility has started to recover towards replacement level, mostly in Europe. The results also indicate that the potential support ratio (persons aged 20–64 per person aged 65+) will almost certainly decline dramatically in most countries over the coming decades. PMID:22908249

Viability of the Alaskan breeding population of Steller’s eiders

USGS Publications Warehouse

Dunham, Kylee; Grand, James B.

2016-10-11

The U.S. Fish and Wildlife Service is tasked with setting objective and measurable criteria for delisting species or populations listed under the Endangered Species Act. Determining the acceptable threshold for extinction risk for any species or population is a challenging task, particularly when facing marked uncertainty. The Alaskan breeding population of Steller’s eiders (Polysticta stelleri) was listed as threatened under the Endangered Species Act in 1997 because of a perceived decline in abundance throughout their nesting range and geographic isolation from the Russian breeding population. Previous genetic studies and modeling efforts, however, suggest that there may be dispersal from the Russian breeding population. Additionally, evidence exists of population level nonbreeding events. Research was conducted to estimate population viability of the Alaskan breeding population of Steller’s eiders, using both an open and closed model of population process for this threatened population. Projections under a closed population model suggest this population has a 100 percent probability of extinction within 42 years. Projections under an open population model suggest that with immigration there is no probability of permanent extinction. Because of random immigration process and nonbreeding behavior, however, it is likely that this population will continue to be present in low and highly variable numbers on the breeding grounds in Alaska. Monitoring the winter population, which includes both Russian and Alaskan breeding birds, may offer a more comprehensive indication of population viability.

Bayesian Probabilistic Projection of International Migration.

PubMed

Azose, Jonathan J; Raftery, Adrian E

2015-10-01

We propose a method for obtaining joint probabilistic projections of migration for all countries, broken down by age and sex. Joint trajectories for all countries are constrained to satisfy the requirement of zero global net migration. We evaluate our model using out-of-sample validation and compare point projections to the projected migration rates from a persistence model similar to the method used in the United Nations' World Population Prospects, and also to a state-of-the-art gravity model.

PROJECTED POPULATION-LEVEL EFFECTS OF THIOBENCARB EXPOSURE ON THE MYSID, AMERICAMYSIS BAHIA, AND EXTINCTION PROBABILITY IN A CONCENTRATION-DECAY EXPOSURE SYSTEM

EPA Science Inventory

Population-level effects of the mysid, Americamysis bahia, exposed to varying thiobencarb concentrations were estimated using stage-structured matrix models. A deterministic density-independent matrix model estimated the decrease in population growth rate, l, with increas...

The finite state projection approach to analyze dynamics of heterogeneous populations

NASA Astrophysics Data System (ADS)

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.

An Exploration of the Effect of Community Engagement in Research on Perceived Outcomes of Partnered Mental Health Services Projects*

PubMed Central

Khodyakov, Dmitry; Stockdale, Susan; Jones, Felica; Ohito, Elizabeth; Jones, Andrea; Lizaola, Elizabeth; Mango, Joseph

2011-01-01

Mental health research projects address sensitive issues for vulnerable populations and are implemented in complex environments. Community-Based Participatory Research approaches are recommended for health research on vulnerable populations, but little is known about how variation in participation affects outcomes of partnered research projects. We developed a conceptual model demonstrating the impact of community engagement in research on outcomes of partnered projects. We collected data on key constructs from community and academic leaders of 21 sampled partnered research projects in two cycles of an NIMH research center. We conducted empirical analyses to test the model. Our findings suggest that community engagement in research is positively associated with perceived professional development, as well as political and community impact. PMID:22582144

A new model for care population management.

PubMed

Williams, Jeni

2013-03-01

Steps toward building a population management model of care should include: Identifying the population that would be cared for through a population management initiative. Conducting an actuarial analysis for this population, reviewing historical utilization and cost data and projecting changes in utilization. Investing in data infrastructure that supports the exchange of data among providers and with payers. Determining potential exposure to downside risk and organizational capacity to assume this risk. Experimenting with payment models and care delivery approaches Hiring care coordinators to manage care for high-risk patients.

Towards More Comprehensive Projections of Urban Heat-Related Mortality: Estimates for New York City Under Multiple Population, Adaptation, and Climate Scenarios

NASA Technical Reports Server (NTRS)

Petkova, Elisaveta P.; Vink, Jan K.; Horton, Radley M.; Gasparrini, Antonio; Bader, Daniel A.; Francis, Joe D.; Kinney, Patrick L.

2016-01-01

High temperatures have substantial impacts on mortality and, with growing concerns about climate change, numerous studies have developed projections of future heat-related deaths around the world. Projections of temperature-related mortality are often limited by insufficient information necessary to formulate hypotheses about population sensitivity to high temperatures and future demographics. This study has derived projections of temperature-related mortality in New York City by taking into account future patterns of adaptation or demographic change, both of which can have profound influences on future health burdens. We adopt a novel approach to modeling heat adaptation by incorporating an analysis of the observed population response to heat in New York City over the course of eight decades. This approach projects heat-related mortality until the end of the 21st century based on observed trends in adaptation over a substantial portion of the 20th century. In addition, we incorporate a range of new scenarios for population change until the end of the 21st century. We then estimate future heat-related deaths in New York City by combining the changing temperature-mortality relationship and population scenarios with downscaled temperature projections from the 33 global climate models (GCMs) and two Representative Concentration Pathways (RCPs).The median number of projected annual heat-related deaths across the 33 GCMs varied greatly by RCP and adaptation and population change scenario, ranging from 167 to 3331 in the 2080s compared to 638 heat-related deaths annually between 2000 and 2006.These findings provide a more complete picture of the range of potential future heat-related mortality risks across the 21st century in New York, and highlight the importance of both demographic change and adaptation responses in modifying future risks.

Dynamics of newly established elk populations

USGS Publications Warehouse

Sargeant, G.A.; Oehler, M.W.

2007-01-01

The dynamics of newly established elk (Cervus elaphus) populations can provide insights about maximum sustainable rates of reproduction, survival, and increase. However, data used to estimate rates of increase typically have been limited to counts and rarely have included complementary estimates of vital rates. Complexities of population dynamics cannot be understood without considering population processes as well as population states. We estimated pregnancy rates, survival rates, age ratios, and sex ratios for reintroduced elk at Theodore Roosevelt National Park, North Dakota, USA; combined vital rates in a population projection model; and compared model projections with observed elk numbers and population ratios. Pregnancy rates in January (early in the second trimester of pregnancy) averaged 54.1% (SE = 5.4%) for subadults and 91.0% (SE = 1.7%) for adults, and 91.6% of pregnancies resulted in recruitment at 8 months. Annual survival rates of adult females averaged 0.96 (95% CI = 0.94-0.98) with hunting included and 0.99 (95% CI = 0.97-0.99) with hunting excluded from calculations. Our fitted model explained 99.8% of past variation in population estimates and represents a useful new tool for short-term management planning. Although we found no evidence of temporal variation in vital rates, variation in population composition caused substantial variation in projected rates of increase (??=1.20-1.36). Restoring documented hunter harvests and removals of elk by the National Park Service led to a potential rate of ?? = 1.26. Greater rates of increase substantiated elsewhere were within the expected range of chance variation, given our model and estimates of vital rates. Rates of increase realized by small elk populations are too variable to support inferences about habitat quality or density dependence.

Use of an Inverse Method for Time Series to Estimate the Dynamics of and Management Strategies for the Box Jellyfish Carybdea marsupialis.

PubMed

Bordehore, Cesar; Fuentes, Verónica L; Segarra, Jose G; Acevedo, Melisa; Canepa, Antonio; Raventós, Josep

2015-01-01

Frequently, population ecology of marine organisms uses a descriptive approach in which their sizes and densities are plotted over time. This approach has limited usefulness for design strategies in management or modelling different scenarios. Population projection matrix models are among the most widely used tools in ecology. Unfortunately, for the majority of pelagic marine organisms, it is difficult to mark individuals and follow them over time to determine their vital rates and built a population projection matrix model. Nevertheless, it is possible to get time-series data to calculate size structure and densities of each size, in order to determine the matrix parameters. This approach is known as a "demographic inverse problem" and it is based on quadratic programming methods, but it has rarely been used on aquatic organisms. We used unpublished field data of a population of cubomedusae Carybdea marsupialis to construct a population projection matrix model and compare two different management strategies to lower population to values before year 2008 when there was no significant interaction with bathers. Those strategies were by direct removal of medusae and by reducing prey. Our results showed that removal of jellyfish from all size classes was more effective than removing only juveniles or adults. When reducing prey, the highest efficiency to lower the C. marsupialis population occurred when prey depletion affected prey of all medusae sizes. Our model fit well with the field data and may serve to design an efficient management strategy or build hypothetical scenarios such as removal of individuals or reducing prey. TThis This sdfsdshis method is applicable to other marine or terrestrial species, for which density and population structure over time are available.

PROJECTING POPULATION-LEVEL RESPONSE OF PURPLE SEA URCHINS TO LEAD CONTAMINATION FOR AN ESTUARINE ECOLOGICAL RISK ASSESSMENT

EPA Science Inventory

As part of an ecological risk assessment case study at the Portsmouth naval Shipyard (PNS), Kittery, Maine, USA, the population level effects of lead exposure to purple sea urchin, Arbacia punctulata, were investigated using a stage-classified matrix population model. The model d...

A changing climate: impacts on human exposures to O3 using ...

EPA Pesticide Factsheets

Predicting the impacts of changing climate on human exposure to air pollution requires future scenarios that account for changes in ambient pollutant concentrations, population sizes and distributions, and housing stocks. An integrated methodology to model changes in human exposures due to these impacts was developed by linking climate, air quality, land-use, and human exposure models. This methodology was then applied to characterize changes in predicted human exposures to O3 under multiple future scenarios. Regional climate projections for the U.S. were developed by downscaling global circulation model (GCM) scenarios for three of the Intergovernmental Panel on Climate Change’s (IPCC’s) Representative Concentration Pathways (RCPs) using the Weather Research and Forecasting (WRF) model. The regional climate results were in turn used to generate air quality (concentration) projections using the Community Multiscale Air Quality (CMAQ) model. For each of the climate change scenarios, future U.S. census-tract level population distributions from the Integrated Climate and Land Use Scenarios (ICLUS) model for four future scenarios based on the IPCC’s Special Report on Emissions Scenarios (SRES) storylines were used. These climate, air quality, and population projections were used as inputs to EPA’s Air Pollutants Exposure (APEX) model for 12 U.S. cities. Probability density functions show changes in the population distribution of 8 h maximum daily O3 exposur

Forecasting Financial Resources for Future Traumatic Spinal Cord Injury Care Using Simulation Modeling.

PubMed

Ahn, Henry; Lewis, Rachel; Santos, Argelio; Cheng, Christiana L; Noonan, Vanessa K; Dvorak, Marcel F; Singh, Anoushka; Linassi, A Gary; Christie, Sean; Goytan, Michael; Atkins, Derek

2017-10-15

Survivors of traumatic spinal cord injury (tSCI) have intense healthcare needs during acute and rehabilitation care and often through the rest of life. To prepare for a growing and aging population, simulation modeling was used to forecast the change in healthcare financial resources and long-term patient outcomes between 2012 and 2032. The model was developed with data from acute and rehabilitation care facilities across Canada participating in the Access to Care and Timing project. Future population and tSCI incidence for 2012 and 2032 were predicted with data from Statistics Canada and the Canadian Institute for Health Information. The projected tSCI incidence for 2012 was validated with actual data from the Rick Hansen SCI Registry of the participating facilities. Using a medium growth scenario, in 2032, the projected median age of persons with tSCI is 57 and persons 61 and older will account for 46% of injuries. Admissions to acute and rehabilitation facilities in 2032 were projected to increase by 31% and 25%, respectively. Because of the demographic shift to an older population, an increase in total population life expectancy with tSCI of 13% was observed despite a 22% increase in total life years lost to tSCI between 2012 and 2032. Care cost increased 54%, and rest of life cost increased 37% in 2032, translating to an additional CAD $16.4 million. With the demographics and management of tSCI changing with an aging population, accurate projections for the increased demand on resources will be critical for decision makers when planning the delivery of healthcare after tSCI.

Modeling the hepatitis A epidemiological transition in Brazil and Mexico

PubMed Central

Van Effelterre, Thierry; Guignard, Adrienne; Marano, Cinzia; Rojas, Rosalba; Jacobsen, Kathryn H.

2017-01-01

ABSTRACT Background: Many low- to middle-income countries have completed or are in the process of transitioning from high or intermediate to low endemicity for hepatitis A virus (HAV). Because the risk of severe hepatitis A disease increases with age at infection, decreased incidence that leaves older children and adults susceptible to HAV infection may actually increase the population-level burden of disease from HAV. Mathematical models can be helpful for projecting future epidemiological profiles for HAV. Methods: An age-specific deterministic, dynamic compartmental transmission model with stratification by setting (rural versus urban) was calibrated with country-specific data on demography, urbanization, and seroprevalence of anti-HAV antibodies. HAV transmission was modeled as a function of setting-specific access to safe water. The model was then used to project various HAV-related epidemiological outcomes in Brazil and in Mexico from 1950 to 2050. Results: The projected epidemiological outcomes were qualitatively similar in the 2 countries. The age at the midpoint of population immunity (AMPI) increased considerably and the mean age of symptomatic HAV cases shifted from childhood to early adulthood. The projected overall incidence rate of HAV infections decreased by about two thirds as safe water access improved. However, the incidence rate of symptomatic HAV infections remained roughly the same over the projection period. The incidence rates of HAV infections (all and symptomatic alone) were projected to become similar in rural and urban settings in the next decades. Conclusion: This model featuring population age structure, urbanization and access to safe water as key contributors to the epidemiological transition for HAV was previously validated with data from Thailand and fits equally well with data from Latin American countries. Assuming no introduction of a vaccination program over the projection period, both Brazil and Mexico were projected to experience a continued decrease in HAV incidence rates without any substantial decrease in the incidence rates of symptomatic HAV infections. PMID:28481680

Modeling the hepatitis A epidemiological transition in Brazil and Mexico.

PubMed

Van Effelterre, Thierry; Guignard, Adrienne; Marano, Cinzia; Rojas, Rosalba; Jacobsen, Kathryn H

2017-08-03

Many low- to middle-income countries have completed or are in the process of transitioning from high or intermediate to low endemicity for hepatitis A virus (HAV). Because the risk of severe hepatitis A disease increases with age at infection, decreased incidence that leaves older children and adults susceptible to HAV infection may actually increase the population-level burden of disease from HAV. Mathematical models can be helpful for projecting future epidemiological profiles for HAV. An age-specific deterministic, dynamic compartmental transmission model with stratification by setting (rural versus urban) was calibrated with country-specific data on demography, urbanization, and seroprevalence of anti-HAV antibodies. HAV transmission was modeled as a function of setting-specific access to safe water. The model was then used to project various HAV-related epidemiological outcomes in Brazil and in Mexico from 1950 to 2050. The projected epidemiological outcomes were qualitatively similar in the 2 countries. The age at the midpoint of population immunity (AMPI) increased considerably and the mean age of symptomatic HAV cases shifted from childhood to early adulthood. The projected overall incidence rate of HAV infections decreased by about two thirds as safe water access improved. However, the incidence rate of symptomatic HAV infections remained roughly the same over the projection period. The incidence rates of HAV infections (all and symptomatic alone) were projected to become similar in rural and urban settings in the next decades. This model featuring population age structure, urbanization and access to safe water as key contributors to the epidemiological transition for HAV was previously validated with data from Thailand and fits equally well with data from Latin American countries. Assuming no introduction of a vaccination program over the projection period, both Brazil and Mexico were projected to experience a continued decrease in HAV incidence rates without any substantial decrease in the incidence rates of symptomatic HAV infections.

Adaptation of water resource systems to an uncertain future

NASA Astrophysics Data System (ADS)

Walsh, Claire L.; Blenkinsop, Stephen; Fowler, Hayley J.; Burton, Aidan; Dawson, Richard J.; Glenis, Vassilis; Manning, Lucy J.; Jahanshahi, Golnaz; Kilsby, Chris G.

2016-05-01

Globally, water resources management faces significant challenges from changing climate and growing populations. At local scales, the information provided by climate models is insufficient to support the water sector in making future adaptation decisions. Furthermore, projections of change in local water resources are wrought with uncertainties surrounding natural variability, future greenhouse gas emissions, model structure, population growth, and water consumption habits. To analyse the magnitude of these uncertainties, and their implications for local-scale water resource planning, we present a top-down approach for testing climate change adaptation options using probabilistic climate scenarios and demand projections. An integrated modelling framework is developed which implements a new, gridded spatial weather generator, coupled with a rainfall-runoff model and water resource management simulation model. We use this to provide projections of the number of days and associated uncertainty that will require implementation of demand saving measures such as hose pipe bans and drought orders. Results, which are demonstrated for the Thames Basin, UK, indicate existing water supplies are sensitive to a changing climate and an increasing population, and that the frequency of severe demand saving measures are projected to increase. Considering both climate projections and population growth, the median number of drought order occurrences may increase 5-fold by the 2050s. The effectiveness of a range of demand management and supply options have been tested and shown to provide significant benefits in terms of reducing the number of demand saving days. A decrease in per capita demand of 3.75 % reduces the median frequency of drought order measures by 50 % by the 2020s. We found that increased supply arising from various adaptation options may compensate for increasingly variable flows; however, without reductions in overall demand for water resources such options will be insufficient on their own to adapt to uncertainties in the projected changes in climate and population. For example, a 30 % reduction in overall demand by 2050 has a greater impact on reducing the frequency of drought orders than any of the individual or combinations of supply options; hence, a portfolio of measures is required.

Spatially explicit global population scenarios consistent with the Shared Socioeconomic Pathways

DOE PAGES

Jones, B.; O’Neill, B. C.

2016-07-29

Here we report that the projected size and spatial distribution of the future population are important drivers of global change and key determinants of exposure and vulnerability to hazards. Spatial demographic projections are widely used as inputs to spatial projections of land use, energy use, and emissions, as well as to assessments of the impacts of extreme events, sea level rise, and other climate-related outcomes. To date, however, there are very few global-scale, spatially explicit population projections, and those that do exist are often based on simple scaling or trend extrapolation. Here we present a new set of global, spatiallymore » explicit population scenarios that are consistent with the new Shared Socioeconomic Pathways (SSPs) developed to facilitate global change research. We use a parameterized gravity-based downscaling model to produce projections of spatial population change that are quantitatively consistent with national population and urbanization projections for the SSPs and qualitatively consistent with assumptions in the SSP narratives regarding spatial development patterns. We show that the five SSPs lead to substantially different spatial population outcomes at the continental, national, and sub-national scale. In general, grid cell-level outcomes are most influenced by national-level population change, second by urbanization rate, and third by assumptions about the spatial style of development. However, the relative importance of these factors is a function of the magnitude of the projected change in total population and urbanization for each country and across SSPs. We also demonstrate variation in outcomes considering the example of population existing in a low-elevation coastal zone under alternative scenarios.« less

Spatially explicit global population scenarios consistent with the Shared Socioeconomic Pathways

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jones, B.; O’Neill, B. C.

Here we report that the projected size and spatial distribution of the future population are important drivers of global change and key determinants of exposure and vulnerability to hazards. Spatial demographic projections are widely used as inputs to spatial projections of land use, energy use, and emissions, as well as to assessments of the impacts of extreme events, sea level rise, and other climate-related outcomes. To date, however, there are very few global-scale, spatially explicit population projections, and those that do exist are often based on simple scaling or trend extrapolation. Here we present a new set of global, spatiallymore » explicit population scenarios that are consistent with the new Shared Socioeconomic Pathways (SSPs) developed to facilitate global change research. We use a parameterized gravity-based downscaling model to produce projections of spatial population change that are quantitatively consistent with national population and urbanization projections for the SSPs and qualitatively consistent with assumptions in the SSP narratives regarding spatial development patterns. We show that the five SSPs lead to substantially different spatial population outcomes at the continental, national, and sub-national scale. In general, grid cell-level outcomes are most influenced by national-level population change, second by urbanization rate, and third by assumptions about the spatial style of development. However, the relative importance of these factors is a function of the magnitude of the projected change in total population and urbanization for each country and across SSPs. We also demonstrate variation in outcomes considering the example of population existing in a low-elevation coastal zone under alternative scenarios.« less

Changes in Black-legged Tick Population in New England with Future Climate Change

NASA Astrophysics Data System (ADS)

Krishnan, S.; Huber, M.

2015-12-01

Lyme disease is one of the most frequently reported vector-borne diseases in the United States. In the Northeastern United States, vector transmission is maintained in a horizontal transmission cycle between the vector, the black-legged ticks, and the vertebrate reservoir hosts, which include white-tailed deer, rodents and other medium to large sized mammals. Predicting how vector populations change with future climate change is critical to understanding disease spread in the future, and for developing suitable regional adaptation strategies. For the United States, these predictions have mostly been made using regressions based on field and lab studies, or using spatial suitability studies. However, the relation between tick populations at various life-cycle stages and climate variables are complex, necessitating a mechanistic approach. In this study, we present a framework for driving a mechanistic tick population model with high-resolution regional climate modeling projections. The goal is to estimate changes in black-legged tick populations in New England for the 21st century. The tick population model used is based on the mechanistic approach of Ogden et al., (2005) developed for Canada. Dynamically downscaled climate projections at a 3-kms resolution using the Weather and Research Forecasting Model (WRF) are used to drive the tick population model.

Incorporating parametric uncertainty into population viability analysis models

USGS Publications Warehouse

McGowan, Conor P.; Runge, Michael C.; Larson, Michael A.

2011-01-01

Uncertainty in parameter estimates from sampling variation or expert judgment can introduce substantial uncertainty into ecological predictions based on those estimates. However, in standard population viability analyses, one of the most widely used tools for managing plant, fish and wildlife populations, parametric uncertainty is often ignored in or discarded from model projections. We present a method for explicitly incorporating this source of uncertainty into population models to fully account for risk in management and decision contexts. Our method involves a two-step simulation process where parametric uncertainty is incorporated into the replication loop of the model and temporal variance is incorporated into the loop for time steps in the model. Using the piping plover, a federally threatened shorebird in the USA and Canada, as an example, we compare abundance projections and extinction probabilities from simulations that exclude and include parametric uncertainty. Although final abundance was very low for all sets of simulations, estimated extinction risk was much greater for the simulation that incorporated parametric uncertainty in the replication loop. Decisions about species conservation (e.g., listing, delisting, and jeopardy) might differ greatly depending on the treatment of parametric uncertainty in population models.

LONG-TERM PROJECTIONS OF EASTERN OYSTER POPULATIONS UNDER VARIOUS MANAGEMENT SCENARIOS

EPA Science Inventory

Time series of fishery-dependent and fishery-independent data were used to parameterize a model of oyster population dynamics for Maryland's Chesapeake Bay. Model parameters are (1) fishing mortality, estimated from differences between predicted and reported landings scaled to a ...

About ICLUS

EPA Pesticide Factsheets

ICLUS is a project for developing scenarios broadly consistent with global-scale, peer-reviewed storylines of population growth and economic development, which are used by climate change modelers to develop projections of future climate.

Projecting community changes in hazard exposure to support long-term risk reduction: A case study of tsunami hazards in the U.S. Pacific Northwest

USGS Publications Warehouse

Sleeter, Benjamin M.; Wood, Nathan J.; Soulard, Christopher E.; Wilson, Tamara

2017-01-01

Tsunamis have the potential to cause considerable damage to communities along the U.S. Pacific Northwest coastline. As coastal communities expand over time, the potential societal impact of tsunami inundation changes. To understand how community exposure to tsunami hazards may change in coming decades, we projected future development (i.e. urban, residential, and rural), households, and residents over a 50-year period (2011–2061) along the Washington, Oregon, and northern California coasts. We created a spatially explicit, land use/land cover, state-and-transition simulation model to project future developed land use based on historical development trends. We then compared our development projection results to tsunami-hazard zones associated with a Cascadia subduction zone (CSZ) earthquake. Changes in tsunami-hazard exposure by 2061 were estimated for 50 incorporated cities, 7 tribal reservations, and 17 counties relative to current (2011) estimates. Across the region, 2061 population exposure in tsunami-hazard zones was projected to increase by 3880 households and 6940 residents. The top ten communities with highest population exposure to CSZ-related tsunamis in 2011 are projected to remain the areas with the highest population exposure by 2061. The largest net population increases in tsunami-hazard zones were projected in the unincorporated portions of several counties, including Skagit, Coos, and Humboldt. Land-change simulation modeling of projected future development serves as an exploratory tool aimed at helping local governments understand the hazard-exposure implications of community growth and to include this knowledge in risk-reduction planning.

Forecasting Financial Resources for Future Traumatic Spinal Cord Injury Care Using Simulation Modeling

PubMed Central

Ahn, Henry; Lewis, Rachel; Santos, Argelio; Cheng, Christiana L.; Dvorak, Marcel F.; Singh, Anoushka; Linassi, A. Gary; Christie, Sean; Goytan, Michael; Atkins, Derek

2017-01-01

Abstract Survivors of traumatic spinal cord injury (tSCI) have intense healthcare needs during acute and rehabilitation care and often through the rest of life. To prepare for a growing and aging population, simulation modeling was used to forecast the change in healthcare financial resources and long-term patient outcomes between 2012 and 2032. The model was developed with data from acute and rehabilitation care facilities across Canada participating in the Access to Care and Timing project. Future population and tSCI incidence for 2012 and 2032 were predicted with data from Statistics Canada and the Canadian Institute for Health Information. The projected tSCI incidence for 2012 was validated with actual data from the Rick Hansen SCI Registry of the participating facilities. Using a medium growth scenario, in 2032, the projected median age of persons with tSCI is 57 and persons 61 and older will account for 46% of injuries. Admissions to acute and rehabilitation facilities in 2032 were projected to increase by 31% and 25%, respectively. Because of the demographic shift to an older population, an increase in total population life expectancy with tSCI of 13% was observed despite a 22% increase in total life years lost to tSCI between 2012 and 2032. Care cost increased 54%, and rest of life cost increased 37% in 2032, translating to an additional CAD $16.4 million. With the demographics and management of tSCI changing with an aging population, accurate projections for the increased demand on resources will be critical for decision makers when planning the delivery of healthcare after tSCI. PMID:28594315

A Capstone Project: Closing the Achievement Gap of English Learners in Literacy at Sunshine Elementary School Using the Gap Analysis Model

ERIC Educational Resources Information Center

Herrera, Juan Carlos

2013-01-01

This project was an alternative capstone dissertation conducted by a team of three doctoral students. The project focused on systematic and long-term underachievement of the English Language (EL) population of a single school, Sunshine Elementary, using the gap analysis model (Clark and Estes, 2008). More specifically, the purpose of the analysis…

A Capstone Project: Closing the Achievement Gap of English Language Learners at Sunshine Elementary School Using the Gap Analysis Model

ERIC Educational Resources Information Center

Mingo-Long, Enyetta

2013-01-01

This project was an alternative capstone dissertation conducted by a team of three doctoral students. The project focused on systematic and long-term underachievement of the English Language Learner (ELL) population of a single school, Sunshine Elementary, using the gap analysis model (Clark and Estes, 2008). More specifically, the purpose of the…

Towards More Comprehensive Projections of Urban Heat-Related Mortality: Estimates for New York City under Multiple Population, Adaptation, and Climate Scenarios

PubMed Central

Petkova, Elisaveta P.; Vink, Jan K.; Horton, Radley M.; Gasparrini, Antonio; Bader, Daniel A.; Francis, Joe D.; Kinney, Patrick L.

2016-01-01

Background: High temperatures have substantial impacts on mortality and, with growing concerns about climate change, numerous studies have developed projections of future heat-related deaths around the world. Projections of temperature-related mortality are often limited by insufficient information to formulate hypotheses about population sensitivity to high temperatures and future demographics. Objectives: The present study derived projections of temperature-related mortality in New York City by taking into account future patterns of adaptation or demographic change, both of which can have profound influences on future health burdens. Methods: We adopted a novel approach to modeling heat adaptation by incorporating an analysis of the observed population response to heat in New York City over the course of eight decades. This approach projected heat-related mortality until the end of the 21st century based on observed trends in adaptation over a substantial portion of the 20th century. In addition, we incorporated a range of new scenarios for population change until the end of the 21st century. We then estimated future heat-related deaths in New York City by combining the changing temperature–mortality relationship and population scenarios with downscaled temperature projections from the 33 global climate models (GCMs) and two Representative Concentration Pathways (RCPs). Results: The median number of projected annual heat-related deaths across the 33 GCMs varied greatly by RCP and adaptation and population change scenario, ranging from 167 to 3,331 in the 2080s compared with 638 heat-related deaths annually between 2000 and 2006. Conclusions: These findings provide a more complete picture of the range of potential future heat-related mortality risks across the 21st century in New York City, and they highlight the importance of both demographic change and adaptation responses in modifying future risks. Citation: Petkova EP, Vink JK, Horton RM, Gasparrini A, Bader DA, Francis JD, Kinney PL. 2017. Towards more comprehensive projections of urban heat-related mortality: estimates for New York City under multiple population, adaptation, and climate scenarios. Environ Health Perspect 125:47–55; http://dx.doi.org/10.1289/EHP166 PMID:27337737

Towards More Comprehensive Projections of Urban Heat-Related Mortality: Estimates for New York City under Multiple Population, Adaptation, and Climate Scenarios.

PubMed

Petkova, Elisaveta P; Vink, Jan K; Horton, Radley M; Gasparrini, Antonio; Bader, Daniel A; Francis, Joe D; Kinney, Patrick L

2017-01-01

High temperatures have substantial impacts on mortality and, with growing concerns about climate change, numerous studies have developed projections of future heat-related deaths around the world. Projections of temperature-related mortality are often limited by insufficient information to formulate hypotheses about population sensitivity to high temperatures and future demographics. The present study derived projections of temperature-related mortality in New York City by taking into account future patterns of adaptation or demographic change, both of which can have profound influences on future health burdens. We adopted a novel approach to modeling heat adaptation by incorporating an analysis of the observed population response to heat in New York City over the course of eight decades. This approach projected heat-related mortality until the end of the 21st century based on observed trends in adaptation over a substantial portion of the 20th century. In addition, we incorporated a range of new scenarios for population change until the end of the 21st century. We then estimated future heat-related deaths in New York City by combining the changing temperature-mortality relationship and population scenarios with downscaled temperature projections from the 33 global climate models (GCMs) and two Representative Concentration Pathways (RCPs). The median number of projected annual heat-related deaths across the 33 GCMs varied greatly by RCP and adaptation and population change scenario, ranging from 167 to 3,331 in the 2080s compared with 638 heat-related deaths annually between 2000 and 2006. These findings provide a more complete picture of the range of potential future heat-related mortality risks across the 21st century in New York City, and they highlight the importance of both demographic change and adaptation responses in modifying future risks. Citation: Petkova EP, Vink JK, Horton RM, Gasparrini A, Bader DA, Francis JD, Kinney PL. 2017. Towards more comprehensive projections of urban heat-related mortality: estimates for New York City under multiple population, adaptation, and climate scenarios. Environ Health Perspect 125:47-55; http://dx.doi.org/10.1289/EHP166.

77 FR 3450 - Guidelines for Assessing Marine Mammal Stocks

Federal Register 2010, 2011, 2012, 2013, 2014

2012-01-24

... population trend model are available, such a model can be used to influence the uncertainty projections....) voluntarily submitted by the commenter may be publicly accessible. Do not submit Confidential Business... distribution and abundance of the stock, population growth rates and trends, estimates of annual human-caused...

Impact of transient climate change upon Grouse population dynamics in the Italian Alps

NASA Astrophysics Data System (ADS)

Pirovano, Andrea; Bocchiola, Daniele

2010-05-01

Understanding the effect of short to medium term weather condition, and of transient global warming upon wildlife species life history is essential to predict the demographic consequences therein, and possibly develop adaptation strategies, especially in game species, where hunting mortality may play an important role in population dynamics. We carried out a preliminary investigation of observed impact of weather variables upon population dynamics indexes of three alpine Grouse species (i.e. Rock Ptarmigan, Lagopus Mutus, Black Grouse, Tetrao Tetrix, Rock Partridge, Alectoris Graeca), nested within central Italian Alps, based upon 15 years (1995-2009) of available censuses data, provided by the Sondrio Province authority. We used a set of climate variables already highlighted within recent literature for carrying considerable bearing on Grouse population dynamics, including e.g. temperature at hatching time and during winter, snow cover at nesting, and precipitation during nursing period. We then developed models of Grouses' population dynamics by explicitly driving population change according to their dependence upon the significant weather variables and population density and we evaluated objective indexes to assess the so obtained predictive power. Eventually, we develop projection of future local climate, based upon locally derived trends, and upon projections from GCMs (A2 IPCC storyline) already validated for the area, to project forward in time (until 2100 or so) the significant climatic variables, which we then use to force population dynamics models of the target species. The projected patterns obtained through this exercise are discussed and compared against those expected under stationary climate conditions at present, and preliminary conclusions are drawn.

Statistical Tools for Fitting Models of the Population Consequences of Acoustic Disturbance to Data from Marine Mammal Populations (PCAD Tools II)

DTIC Science & Technology

2014-09-30

Consequences of Acoustic Disturbance to Data from Marine Mammal Populations (PCAD Tools II) Len Thomas, John Harwood, Catriona Harris, and Robert S... mammals changes over time. This project will develop statistical tools to allow mathematical models of the population consequences of acoustic...disturbance to be fitted to data from marine mammal populations. We will work closely with Phase II of the ONR PCAD Working Group, and will provide

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

USGS Publications Warehouse

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 inhospitable to pronghorn persistence. This realization informs and steers conservation and management decisions for pronghorn in North America, while exemplifying how similar research can aid ungulates inhabiting arid regions and confronting similar circumstances elsewhere.

The Conceptualization, Development and Implementation of a Comprehensive Guidance Model. [Georgia Comprehensive K-14 Career Guidance Project.] Final Report, July 1, 1975 through June 30, 1977.

ERIC Educational Resources Information Center

Vail, Paul

A project was conducted to develop, test, and implement a comprehensive program for Georgia school systems, grades K-14. The target population included regular students, students with special needs, out-of-school youth, and adults experiencing career problems. Project objectives were to develop a K-14 guidance model, develop a state/local…

Assessing the potential impact and uncertainty of climate, land use change and demographic trends on malaria transmission in Africa by 2050.

NASA Astrophysics Data System (ADS)

Tompkins, Adrian; Caporaso, Luca; Colon-Gonzalez, Felipe

2014-05-01

Previous analyses of data has shown that in addition to variability and longer term trends in climate variables, both land use change (LUC) and population mobility and urbanisation trends can impact malaria transmission intensities and socio-economic burden. With the new regional VECTRI dynamical malaria model it is now possible to examine these in an integrated modelling framework. Using 5 global climate models which were bias corrected using the WATCH data for the recent ISIMIP project, the four Representative Concentration Pathways (RCP), population projections disaggregated from the Shared Socioeconomic Pathways (SSP) and Land use change from the HYDE model output used in the CMIP5 process, we construct a multi-member ensemble of malaria transmission intensity projections for 2050. The ensemble integrations indicate that climate has the leading impact on malaria changes, but that population growth and urbanisation can offset the effect of climate locally. LUC impacts can also be significant on the local scale but their assessment is highly uncertain and only indicative in this study. It is argued that the study should be repeated with a range of malaria models or VECTRI configurations in order to assess the additional uncertainty due to the malaria model assumptions.

Inferential and forward projection modeling to evaluate options for controlling invasive mammals on islands.

PubMed

Anderson, D P; McMurtrie, P; Edge, K-A; Baxter, P W J; Byrom, A E

2016-12-01

Successful pest-mammal eradications from remote islands have resulted in important biodiversity benefits. Near-shore islands can also serve as refuges for native biota but require ongoing effort to maintain low-pest or pest-free status. Three management options are available in the presence of reinvasion risk: (1) control-to-zero density, in which immigration may occur but reinvaders are removed; (2) sustained population suppression (to relatively low numbers); or (3) no action. Biodiversity benefits can result from options one and two. The management challenge is to make evidence-based decisions on the selection of an appropriate objective and to identify a financially feasible control strategy that has a high probability of success. This requires understanding the pest species population dynamics and how it will respond to a range of potential management strategies, each with an associated financial cost. We developed a two-stage modeling approach that consisted of (1) Bayesian inferential modeling to estimate parameters for a model of pest population dynamics and control, and (2) a forward projection model to simulate a range of plausible management scenarios and quantify the probability of obtaining zero density within four years. We applied the model to an ongoing, six-year trapping program to control stoats (Mustela erminea) on Resolution Island, New Zealand. Zero density has not yet been achieved. Results demonstrate that management objectives were impeded by a combination of a highly fecund population, insufficient trap attractiveness, and a substantial proportion of the population that did not enter traps. Immigration is known to occur because the founding population arrived on the island by swimming from the mainland. However, immigration rate during this study was indistinguishable from zero. The forward projection modeling showed that control-to-zero density was feasible but required greater than a two-fold budget increase to intensify the trapping rate relative to population growth. The two-stage modeling provides the foundation for a management program in which broad-scale trials of additional trapping effort or improved trap lures would test model predictions and increase our understanding of system dynamics. © 2016 by the Ecological Society of America.

Arthroplasty Utilization in the United States is Predicted by Age-Specific Population Groups.

PubMed

Bashinskaya, Bronislava; Zimmerman, Ryan M; Walcott, Brian P; Antoci, Valentin

2012-01-01

Osteoarthritis is a common indication for hip and knee arthroplasty. An accurate assessment of current trends in healthcare utilization as they relate to arthroplasty may predict the needs of a growing elderly population in the United States. First, incidence data was queried from the United States Nationwide Inpatient Sample from 1993 to 2009. Patients undergoing total knee and hip arthroplasty were identified. Then, the United States Census Bureau was queried for population data from the same study period as well as to provide future projections. Arthroplasty followed linear regression models with the population group >64 years in both hip and knee groups. Projections for procedure incidence in the year 2050 based on these models were calculated to be 1,859,553 cases (hip) and 4,174,554 cases (knee). The need for hip and knee arthroplasty is expected to grow significantly in the upcoming years, given population growth predictions.

International migration beyond gravity: A statistical model for use in population projections

PubMed Central

Cohen, Joel E.; Roig, Marta; Reuman, Daniel C.; GoGwilt, Cai

2008-01-01

International migration will play an increasing role in the demographic future of most nations if fertility continues to decline globally. We developed an algorithm to project future numbers of international migrants from any country or region to any other. The proposed generalized linear model (GLM) used geographic and demographic independent variables only (the population and area of origins and destinations of migrants, the distance between origin and destination, the calendar year, and indicator variables to quantify nonrandom characteristics of individual countries). The dependent variable, yearly numbers of migrants, was quantified by 43653 reports from 11 countries of migration from 228 origins and to 195 destinations during 1960–2004. The final GLM based on all data was selected by the Bayesian information criterion. The number of migrants per year from origin to destination was proportional to (population of origin)0.86(area of origin)−0.21(population of destination)0.36(distance)−0.97, multiplied by functions of year and country-specific indicator variables. The number of emigrants from an origin depended on both its population and its population density. For a variable initial year and a fixed terminal year 2004, the parameter estimates appeared stable. Multiple R2, the fraction of variation in log numbers of migrants accounted for by the starting model, improved gradually with recentness of the data: R2 = 0.57 for data from 1960 to 2004, R2 = 0.59 for 1985–2004, R2 = 0.61 for 1995–2004, and R2 = 0.64 for 2000–2004. The migration estimates generated by the model may be embedded in deterministic or stochastic population projections. PMID:18824693

Projections of preventable risks for cardiovascular disease in Canada to 2021: a microsimulation modelling approach

PubMed Central

Manuel, Douglas G.; Tuna, Meltem; Hennessy, Deirdre; Okhmatovskaia, Anya; Finès, Philippe; Tanuseputro, Peter; Tu, Jack V.; Flanagan, William

2014-01-01

Background Reductions in preventable risks associated with cardiovascular disease have contributed to a steady decrease in its incidence over the past 50 years in most developed countries. However, it is unclear whether this trend will continue. Our objective was to examine future risk by projecting trends in preventable risk factors in Canada to 2021. Methods We created a population-based microsimulation model using national data on births, deaths and migration; socioeconomic data; cardiovascular disease risk factors; and algorithms for changes in these risk factors (based on sociodemographic characteristics and previous cardiovascular disease risk). An initial population of 22.5 million people, representing the Canadian adult population in 2001, had 13 characteristics including the risk factors used in clinical risk prediction. There were 6.1 million potential exposure profiles for each person each year. Outcome measures included annual prevalence of risk factors (smoking, obesity, diabetes, hypertension and lipid levels) and of co-occurring risks. Results From 2003 to 2009, the projected risks of cardiovascular disease based on the microsimulation model closely approximated those based on national surveys. Except for obesity and diabetes, all risk factors were projected to decrease through to 2021. The largest projected decreases were for the prevalence of smoking (from 25.7% in 2001 to 17.7% in 2021) and uncontrolled hypertension (from 16.1% to 10.8%). Between 2015 and 2017, obesity was projected to surpass smoking as the most prevalent risk factor. Interpretation Risks of cardiovascular disease are projected to decrease modestly in Canada, leading to a likely continuing decline in its incidence. PMID:25077135

Increase in Total Joint Arthroplasty Projected from 2014 to 2046 in Australia: A Conservative Local Model With International Implications.

PubMed

Inacio, Maria C S; Graves, Stephen E; Pratt, Nicole L; Roughead, Elizabeth E; Nemes, Szilard

2017-08-01

The incidence of joint arthroplasty is increasing worldwide. International estimates of future demand for joint arthroplasty have used models that propose either an exponential future increase, despite obvious system constraints, or static increases, which do not account for past trends. Country-specific projection estimates that address limitations of past projections are necessary. In Australia, a high-income country with the 7th highest incidence of TKA and 15th highest incidence of THA of the Organization for Economic Cooperation and Development (OECD) countries, the volume of TKAs and THAs increased 198% between 1994 and 2014. To determine the projected incidence and volume of primary TKAs and THAs from 2014 to 2046 in the Australian population older than 40 years. Australian State and Territory Health Department data were used to identify TKAs and THAs performed between 1994 and 1995 and 2013 and 2014. The Australian Bureau of Statistics was the source of the population estimates for the same periods and population-projected estimates until 2046. The incidence rate (IR), 95% CI, and prediction interval (PI) of TKAs and THAs per 100,000 Australian citizens older than 40 years were calculated. Future IRs were estimated using a logistic model, and volume was calculated from projected IR and population. The logistic growth model assumes the existence of an upper limit of the TKA and THA incidences and a growth rate directly related to this incidence. At the beginning, when the observed incidence is much lower than the asymptote, the increase is exponential, but it decreases as it approaches the upper limit. A 66% increase in the IR of primary THAs between 2013 and 2046 is projected for Australia (2013: IR = 307 per 100,000, [95% CI, 262-329 per 100,000] compared with 2046: IR= 510 per 100,000, [95% PI, 98-567 per 100,000]), which translates to a 219% increase in the volume during this period. For TKAs the IR is expected to increase by 26% by 2046 (IR = 575 per 100,000; 95% PI, 402-717 per 100,000) compared with 2013 (IR = 437 per 100,000; 95% CI, 397-479 per 100,000) and the volume to increase by 142%. A large increase in the volume of arthroplasties is expected using a conservative projection model that accounts for past surgical trends and future population changes in Australia. These findings have international implications, as they show that using country- specific, conservative projection approaches, a substantial increase in the number of these procedures is expected. This increase in joint arthroplasty volume will require appropriate workforce planning, resource allocation, and budget planning so that demand can be met. Level II, economic and decision analysis.

Projected response of an endangered marine turtle population to climate change

NASA Astrophysics Data System (ADS)

Saba, Vincent S.; Stock, Charles A.; Spotila, James R.; Paladino, Frank V.; Tomillo, Pilar Santidrián

2012-11-01

Assessing the potential impacts of climate change on individual species and populations is essential for the stewardship of ecosystems and biodiversity. Critically endangered leatherback turtles in the eastern Pacific Ocean are excellent candidates for such an assessment because their sensitivity to contemporary climate variability has been substantially studied. If incidental fisheries mortality is eliminated, this population still faces the challenge of recovery in a rapidly changing climate. Here we combined an Earth system model, climate model projections assessed by the Intergovernmental Panel on Climate Change and a population dynamics model to estimate a 7% per decade decline in the Costa Rica nesting population over the twenty-first century. Whereas changes in ocean conditions had a small effect on the population, the ~2.5°C warming of the nesting beach was the primary driver of the decline through reduced hatching success and hatchling emergence rate. Hatchling sex ratio did not substantially change. Adjusting nesting phenology or changing nesting sites may not entirely prevent the decline, but could offset the decline rate. However, if future observations show a long-term decline in hatching success and emergence rate, anthropogenic climate mitigation of nests (for example, shading, irrigation) may be able to preserve the nesting population.

Singapore Genome Variation Project: a haplotype map of three Southeast Asian populations.

PubMed

Teo, Yik-Ying; Sim, Xueling; Ong, Rick T H; Tan, Adrian K S; Chen, Jieming; Tantoso, Erwin; Small, Kerrin S; Ku, Chee-Seng; Lee, Edmund J D; Seielstad, Mark; Chia, Kee-Seng

2009-11-01

The Singapore Genome Variation Project (SGVP) provides a publicly available resource of 1.6 million single nucleotide polymorphisms (SNPs) genotyped in 268 individuals from the Chinese, Malay, and Indian population groups in Southeast Asia. This online database catalogs information and summaries on genotype and phased haplotype data, including allele frequencies, assessment of linkage disequilibrium (LD), and recombination rates in a format similar to the International HapMap Project. Here, we introduce this resource and describe the analysis of human genomic variation upon agglomerating data from the HapMap and the Human Genome Diversity Project, providing useful insights into the population structure of the three major population groups in Asia. In addition, this resource also surveyed across the genome for variation in regional patterns of LD between the HapMap and SGVP populations, and for signatures of positive natural selection using two well-established metrics: iHS and XP-EHH. The raw and processed genetic data, together with all population genetic summaries, are publicly available for download and browsing through a web browser modeled with the Generic Genome Browser.

Singapore Genome Variation Project: A haplotype map of three Southeast Asian populations

PubMed Central

Teo, Yik-Ying; Sim, Xueling; Ong, Rick T.H.; Tan, Adrian K.S.; Chen, Jieming; Tantoso, Erwin; Small, Kerrin S.; Ku, Chee-Seng; Lee, Edmund J.D.; Seielstad, Mark; Chia, Kee-Seng

2009-01-01

The Singapore Genome Variation Project (SGVP) provides a publicly available resource of 1.6 million single nucleotide polymorphisms (SNPs) genotyped in 268 individuals from the Chinese, Malay, and Indian population groups in Southeast Asia. This online database catalogs information and summaries on genotype and phased haplotype data, including allele frequencies, assessment of linkage disequilibrium (LD), and recombination rates in a format similar to the International HapMap Project. Here, we introduce this resource and describe the analysis of human genomic variation upon agglomerating data from the HapMap and the Human Genome Diversity Project, providing useful insights into the population structure of the three major population groups in Asia. In addition, this resource also surveyed across the genome for variation in regional patterns of LD between the HapMap and SGVP populations, and for signatures of positive natural selection using two well-established metrics: iHS and XP-EHH. The raw and processed genetic data, together with all population genetic summaries, are publicly available for download and browsing through a web browser modeled with the Generic Genome Browser. PMID:19700652

Trends and predicted trends in presentations of older people to Australian emergency departments: effects of demand growth, population aging and climate change.

PubMed

Burkett, Ellen; Martin-Khan, Melinda G; Scott, Justin; Samanta, Mayukh; Gray, Leonard C

2017-07-01

Objectives The aim of the present study was to describe trends in and age and gender distributions of presentations of older people to Australian emergency departments (EDs) from July 2006 to June 2011, and to develop ED utilisation projections to 2050. Methods A retrospective analysis of data collected in the National Non-admitted Patient Emergency Department Care Database was undertaken to assess trends in ED presentations. Three standard Australian Bureau of Statistics population growth models, with and without adjustment for current trends in ED presentation growth and effects of climate change, were examined with projections of ED presentations across three age groups (0-64, 65-84 and ≥85 years) to 2050. Results From 2006-07 to 2010-11, ED presentations increased by 12.63%, whereas the Australian population over this time increased by only 7.26%. Rates of presentation per head of population were greatest among those aged ≥85 years. Projections of ED presentations to 2050 revealed that overall ED presentations are forecast to increase markedly, with the rate of increase being most marked for older people. Conclusion Growth in Australian ED presentations from 2006-07 to 2010-11 was greater than that expected from population growth alone. The predicted changes in demand for ED care will only be able to be optimally managed if Australian health policy, ED funding instruments and ED models of care are adjusted to take into account the specific care and resource needs of older people. What is known about the topic? Rapid population aging is anticipated over coming decades. International studies and specific local-level Australian studies have demonstrated significant growth in ED presentations. There have been no prior national-level Australian studies of ED presentation trends by age group. What does this paper add? The present study examined national ED presentation trends from July 2006 to June 2011, with specific emphasis on trends in presentation by age group. ED presentation growth was found to exceed population growth in all age groups. The rate of ED presentations per head of population was highest among those aged ≥85 years. ED utilisation projections to 2050, using standard Australian Bureau of Statistics population modelling, with and without adjustment for current ED growth, were developed. The projections demonstrated linear growth in ED presentation for those aged 0-84 years, with growth in ED presentations of the ≥85 year age group demonstrating marked acceleration after 2030. What are the implications for practitioners? Growth in ED presentations exceeding population growth suggests that current models of acute health care delivery require review to ensure that optimal care is delivered in the most fiscally efficient manner. Trends in presentation of older people emphasise the imperative for ED workforce planning and education in care of this complex patient cohort, and the requirement to review funding models to incentivise investment in ED avoidance and substitutive care models targeting older people.

Influence of demographic changes on the impact of vaccination against varicella and herpes zoster in Germany - a mathematical modelling study.

PubMed

Horn, Johannes; Damm, Oliver; Greiner, Wolfgang; Hengel, Hartmut; Kretzschmar, Mirjam E; Siedler, Anette; Ultsch, Bernhard; Weidemann, Felix; Wichmann, Ole; Karch, André; Mikolajczyk, Rafael T

2018-01-09

Epidemiological studies suggest that reduced exposure to varicella might lead to an increased risk for herpes zoster (HZ). Reduction of exposure to varicella is a consequence of varicella vaccination but also of demographic changes. We analyzed how the combination of vaccination programs and demographic dynamics will affect the epidemiology of varicella and HZ in Germany over the next 50 years. We used a deterministic dynamic compartmental model to assess the impact of different varicella and HZ vaccination strategies on varicella and HZ epidemiology in three demographic scenarios, namely the projected population for Germany, the projected population additionally accounting for increased immigration as observed in 2015/2016, and a stationary population. Projected demographic changes alone result in an increase of annual HZ cases by 18.3% and a decrease of varicella cases by 45.7% between 1990 and 2060. Independently of the demographic scenario, varicella vaccination reduces the cumulative number of varicella cases until 2060 by approximately 70%, but also increases HZ cases by 10%. Unlike the currently licensed live attenuated HZ vaccine, the new subunit vaccine candidate might completely counteract this effect. Relative vaccine effects were consistent across all demographic scenarios. Demographic dynamics will be a major determinant of HZ epidemiology in the next 50 years. While stationary population models are appropriate for assessing vaccination impact, models incorporating realistic population structures allow a direct comparison to surveillance data and can thus provide additional input for immunization decision-making and resource planning.

Effects of climate change on an emperor penguin population: analysis of coupled demographic and climate models.

PubMed

Jenouvrier, Stéphanie; Holland, Marika; Stroeve, Julienne; Barbraud, Christophe; Weimerskirch, Henri; Serreze, Mark; Caswell, Hal

2012-09-01

Sea ice conditions in the Antarctic affect the life cycle of the emperor penguin (Aptenodytes forsteri). We present a population projection for the emperor penguin population of Terre Adélie, Antarctica, by linking demographic models (stage-structured, seasonal, nonlinear, two-sex matrix population models) to sea ice forecasts from an ensemble of IPCC climate models. Based on maximum likelihood capture-mark-recapture analysis, we find that seasonal sea ice concentration anomalies (SICa ) affect adult survival and breeding success. Demographic models show that both deterministic and stochastic population growth rates are maximized at intermediate values of annual SICa , because neither the complete absence of sea ice, nor heavy and persistent sea ice, would provide satisfactory conditions for the emperor penguin. We show that under some conditions the stochastic growth rate is positively affected by the variance in SICa . We identify an ensemble of five general circulation climate models whose output closely matches the historical record of sea ice concentration in Terre Adélie. The output of this ensemble is used to produce stochastic forecasts of SICa , which in turn drive the population model. Uncertainty is included by incorporating multiple climate models and by a parametric bootstrap procedure that includes parameter uncertainty due to both model selection and estimation error. The median of these simulations predicts a decline of the Terre Adélie emperor penguin population of 81% by the year 2100. We find a 43% chance of an even greater decline, of 90% or more. The uncertainty in population projections reflects large differences among climate models in their forecasts of future sea ice conditions. One such model predicts population increases over much of the century, but overall, the ensemble of models predicts that population declines are far more likely than population increases. We conclude that climate change is a significant risk for the emperor penguin. Our analytical approach, in which demographic models are linked to IPCC climate models, is powerful and generally applicable to other species and systems. © 2012 Blackwell Publishing Ltd.

Developing population models with data from marked individuals

USGS Publications Warehouse

Hae Yeong Ryu,; Kevin T. Shoemaker,; Eva Kneip,; Anna Pidgeon,; Patricia Heglund,; Brooke Bateman,; Thogmartin, Wayne E.; Reşit Akçakaya,

2016-01-01

Population viability analysis (PVA) is a powerful tool for biodiversity assessments, but its use has been limited because of the requirements for fully specified population models such as demographic structure, density-dependence, environmental stochasticity, and specification of uncertainties. Developing a fully specified population model from commonly available data sources – notably, mark–recapture studies – remains complicated due to lack of practical methods for estimating fecundity, true survival (as opposed to apparent survival), natural temporal variability in both survival and fecundity, density-dependence in the demographic parameters, and uncertainty in model parameters. We present a general method that estimates all the key parameters required to specify a stochastic, matrix-based population model, constructed using a long-term mark–recapture dataset. Unlike standard mark–recapture analyses, our approach provides estimates of true survival rates and fecundities, their respective natural temporal variabilities, and density-dependence functions, making it possible to construct a population model for long-term projection of population dynamics. Furthermore, our method includes a formal quantification of parameter uncertainty for global (multivariate) sensitivity analysis. We apply this approach to 9 bird species and demonstrate the feasibility of using data from the Monitoring Avian Productivity and Survivorship (MAPS) program. Bias-correction factors for raw estimates of survival and fecundity derived from mark–recapture data (apparent survival and juvenile:adult ratio, respectively) were non-negligible, and corrected parameters were generally more biologically reasonable than their uncorrected counterparts. Our method allows the development of fully specified stochastic population models using a single, widely available data source, substantially reducing the barriers that have until now limited the widespread application of PVA. This method is expected to greatly enhance our understanding of the processes underlying population dynamics and our ability to analyze viability and project trends for species of conservation concern.

Workforce Projections 2010-2020: Annual Supply and Demand Forecasting Models for Physical Therapists Across the United States.

PubMed

Landry, Michel D; Hack, Laurita M; Coulson, Elizabeth; Freburger, Janet; Johnson, Michael P; Katz, Richard; Kerwin, Joanne; Smith, Megan H; Wessman, Henry C Bud; Venskus, Diana G; Sinnott, Patricia L; Goldstein, Marc

2016-01-01

Health human resources continue to emerge as a critical health policy issue across the United States. The purpose of this study was to develop a strategy for modeling future workforce projections to serve as a basis for analyzing annual supply of and demand for physical therapists across the United States into 2020. A traditional stock-and-flow methodology or model was developed and populated with publicly available data to produce estimates of supply and demand for physical therapists by 2020. Supply was determined by adding the estimated number of physical therapists and the approximation of new graduates to the number of physical therapists who immigrated, minus US graduates who never passed the licensure examination, and an estimated attrition rate in any given year. Demand was determined by using projected US population with health care insurance multiplied by a demand ratio in any given year. The difference between projected supply and demand represented a shortage or surplus of physical therapists. Three separate projection models were developed based on best available data in the years 2011, 2012, and 2013, respectively. Based on these projections, demand for physical therapists in the United States outstrips supply under most assumptions. Workforce projection methodology research is based on assumptions using imperfect data; therefore, the results must be interpreted in terms of overall trends rather than as precise actuarial data-generated absolute numbers from specified forecasting. Outcomes of this projection study provide a foundation for discussion and debate regarding the most effective and efficient ways to influence supply-side variables so as to position physical therapists to meet current and future population demand. Attrition rates or permanent exits out of the profession can have important supply-side effects and appear to have an effect on predicting future shortage or surplus of physical therapists. © 2016 American Physical Therapy Association.

Some comments on the World Energy Conference (WEC) energy demand model

NASA Astrophysics Data System (ADS)

Brandell, L.

1982-04-01

The WEC model, relating the energy demand for a region in a year to gross national product (GNP), aggregated energy prices and elasticity constants, is generalized. The changes that result from the assumption that the elasticity factors are not constant are examined. The resulting differential equation contains the variables energy demand per capita and GNP per capita for the region considered. The effect of time lag in energy demand and the influence of the population growth rate are also included in the model. No projections of the future energy demand were made, but model sensitiveness to the modifications were studied. Time lag effects and population growth effects can raise the projected energy demand for a region by 10% or more.

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

PubMed

Scotson, Lorraine; Fredriksson, Gabriella; Ngoprasert, Dusit; Wong, Wai-Ming; Fieberg, John

2017-01-01

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 all assumptions be clearly stated.

Updates to the Demographic and Spatial Allocation Models to ...

EPA Pesticide Factsheets

EPA's announced the availability of the final report, Updates to the Demographic and Spatial Allocation Models to Produce Integrated Climate and Land Use Scenarios (ICLUS) (Version 2). This update furthered land change modeling by providing nationwide housing development scenarios up to 2100. This newest version includes updated population and land use data sets and addresses limitations identified in ICLUS v1 in both the migration and spatial allocation models. The companion user guide (Final Report) describes the development of ICLUS v2 and the updates that were made to the original data sets and the demographic and spatial allocation models. The GIS tool enables users to run SERGoM with the population projections developed for the ICLUS project and allows users to modify the spatial allocation housing density across the landscape.

ICLUS v1.3 Population Projections

EPA Pesticide Factsheets

Climate and land-use change are major components of global environmental change with feedbacks between these components. The consequences of these interactions show that land use may exacerbate or alleviate climate change effects. Based on these findings it is important to use land-use scenarios that are consistent with the specific assumptions underlying climate-change scenarios. The Integrated Climate and Land-Use Scenarios (ICLUS) project developed land-use outputs that are based on a downscaled version of the Intergovernmental Panel on Climate Change (IPCC) Special Report on Emissions Scenarios (SRES) social, economic, and demographic storylines. ICLUS outputs are derived from a pair of models. A demographic model generates county-level population estimates that are distributed by a spatial allocation model (SERGoM v3) as housing density across the landscape. Land-use outputs were developed for the four main SRES storylines and a baseline (base case). The model is run for the conterminous USA and output is available for each scenario by decade to 2100. In addition to housing density at a 1 hectare spatial resolution, this project also generated estimates of impervious surface at a resolution of 1 square kilometer. This shapefile holds population data for all counties of the conterminous USA for all decades (2010-2100) and SRES population growth scenarios (A1, A2, B1, B2), as well as a 'base case' (BC) scenario, for use in the Integrated Climate and Land Use

Projected asymmetric response of Adélie penguins to Antarctic climate change

NASA Astrophysics Data System (ADS)

Cimino, Megan A.; Lynch, Heather J.; Saba, Vincent S.; Oliver, Matthew J.

2016-06-01

The contribution of climate change to shifts in a species’ geographic distribution is a critical and often unresolved ecological question. Climate change in Antarctica is asymmetric, with cooling in parts of the continent and warming along the West Antarctic Peninsula (WAP). The Adélie penguin (Pygoscelis adeliae) is a circumpolar meso-predator exposed to the full range of Antarctic climate and is undergoing dramatic population shifts coincident with climate change. We used true presence-absence data on Adélie penguin breeding colonies to estimate past and future changes in habitat suitability during the chick-rearing period based on historic satellite observations and future climate model projections. During the contemporary period, declining Adélie penguin populations experienced more years with warm sea surface temperature compared to populations that are increasing. Based on this relationship, we project that one-third of current Adélie penguin colonies, representing ~20% of their current population, may be in decline by 2060. However, climate model projections suggest refugia may exist in continental Antarctica beyond 2099, buffering species-wide declines. Climate change impacts on penguins in the Antarctic will likely be highly site specific based on regional climate trends, and a southward contraction in the range of Adélie penguins is likely over the next century.

The relationship between climate change and the endangered rainforest shrub Triunia robusta (Proteaceae) endemic to southeast Queensland, Australia

NASA Astrophysics Data System (ADS)

Shimizu-Kimura, Yoko; Accad, Arnon; Shapcott, Alison

2017-04-01

Threatened species in rainforests may be vulnerable to climate change, because of their potentially narrow thermal tolerances, small population sizes and restricted distributions. This study modelled climate induced changes on the habitat distribution of the endangered rainforest plant Triunia robusta, endemic to southeast Queensland, Australia. Species distribution models were developed for eastern Australia at 250 m grids and southeast Queensland at 25 m grids using ground-truthed presence records and environmental predictor data. The species’ habitat distribution under the current climate was modelled, and the future potential habitat distributions were projected for the epochs 2030, 2050 and 2070. The eastern Australia model identified several spatially disjunct, broad habitat areas of coastal eastern Australia consistent with the current distribution of rainforests, and projected a southward and upslope contraction driven mainly by average temperatures exceeding current range limits. The southeast Queensland models suggest a dramatic upslope contraction toward locations where the majority of known populations are found. Populations located in the Sunshine Coast hinterland, consistent with past rainforest refugia, are likely to persist long-term. Upgrading the level of protection for less formal nature reserves containing viable populations is a high priority to better protect refugial T. robusta populations with respect to climate change.

The relationship between climate change and the endangered rainforest shrub Triunia robusta (Proteaceae) endemic to southeast Queensland, Australia

PubMed Central

Shimizu-Kimura, Yoko; Accad, Arnon; Shapcott, Alison

2017-01-01

Threatened species in rainforests may be vulnerable to climate change, because of their potentially narrow thermal tolerances, small population sizes and restricted distributions. This study modelled climate induced changes on the habitat distribution of the endangered rainforest plant Triunia robusta, endemic to southeast Queensland, Australia. Species distribution models were developed for eastern Australia at 250 m grids and southeast Queensland at 25 m grids using ground-truthed presence records and environmental predictor data. The species’ habitat distribution under the current climate was modelled, and the future potential habitat distributions were projected for the epochs 2030, 2050 and 2070. The eastern Australia model identified several spatially disjunct, broad habitat areas of coastal eastern Australia consistent with the current distribution of rainforests, and projected a southward and upslope contraction driven mainly by average temperatures exceeding current range limits. The southeast Queensland models suggest a dramatic upslope contraction toward locations where the majority of known populations are found. Populations located in the Sunshine Coast hinterland, consistent with past rainforest refugia, are likely to persist long-term. Upgrading the level of protection for less formal nature reserves containing viable populations is a high priority to better protect refugial T. robusta populations with respect to climate change. PMID:28422136

[Implementing population-based integrated care for a region: a work-in-progress report on the project "Gesundes Kinzigtal"].

PubMed

Hildebrandt, Helmut; Schmitt, Gwendolyn; Roth, Monika; Stunder, Brigitte

2011-01-01

The regional integrated care model "Gesundes Kinzigtal" pursues the idea of integrated health care with special focus on increasing the health gain of the served population. Physicians (general practitioners) and psychotherapists, physiotherapists, hospitals, nursing services, non-profit associations, fitness centers, and health insurance companies work closely together with a regional management company and its programs on prevention and care coordination and enhancement. The 10 year-project is run by a company that was founded by the physician network "MQNK" and "OptiMedis AG", a corporation with public health background specialising in integrated health care. The aim of this project is to enhance prevention and quality of health care for a whole region in a sustainable way, and to decrease costs of care. The article describes the special funding model of the project, the engagement of patients, and the different health and prevention programmes. The programmes and projects are developed, implemented, and evaluated by multidisciplinary teams. Copyright © 2011. Published by Elsevier GmbH.

Higher Education in California: New Goals for the Master Plan. Technical Appendices

ERIC Educational Resources Information Center

Johnson, Hans

2010-01-01

To determine new eligibility goals for California, the author and his colleagues developed a student flow model that projects student enrollment and degrees awarded for each year from 2005 to 2025. To develop the model, they first developed population projections for the state. They also used a plethora of data sources to identify current trends…

Projecting School Psychology Staffing Needs Using a Risk-Adjusted Model.

ERIC Educational Resources Information Center

Stellwagen, Kurt

A model is proposed to project optimal school psychology service ratios based upon the percentages of at risk students enrolled within a given school population. Using the standard 1:1,000 service ratio advocated by The National Association of School Psychologists (NASP) as a starting point, ratios are then adjusted based upon the size of three…

Elucidating the Population Dynamics of Japanese Knotweed Using Integral Projection Models

PubMed Central

Dauer, Joseph T.; Jongejans, Eelke

2013-01-01

Plant demographic studies coupled with population modeling are crucial components of invasive plant management because they inform managers when in a plant’s life cycle it is most susceptible to control efforts. Providing land managers with appropriate data can be especially challenging when there is limited data on potentially important transitions that occur belowground. For 2 years, we monitored 4 clonal Japanese knotweed ( Polygonum cuspidatum ) infestations for emergence, survival, shoot height until leaf senescence, dry shoot biomass after senescence, and rhizome connections for 424 shoots. We developed an integral projection model using both final autumn shoot height and shoot biomass as predictors of survival between years, growth from year to year, and number of rhizomes produced by a shoot (fecundity). Numbers of new shoots within an infestation (population growth rate λ) were projected to increase 13-233% in a year, with the greatest increase at the most frequently disturbed site. Elasticity analysis revealed population growth at 3 of the 4 sites was primarily due to ramet survival between years and to year-to-year growth in shoot height and shoot biomass. Population growth at the fourth site, the most disturbed, was due to the large production of new rhizomes and associated shoots. In contrast to previous studies, our excavation revealed that most of the shoots were not interconnected, suggesting rhizome production may be limited by the size or age of the plants, resource availability, disturbance frequency, or other factors. Future integration of plant population models with more data on belowground growth structures will clarify the critical stages in Japanese knotweed life cycle and support land managers in their management decisions. PMID:24073249

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

PubMed

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.

Coupling population dynamics with earth system models: the POPEM model.

PubMed

Navarro, Andrés; Moreno, Raúl; Jiménez-Alcázar, Alfonso; Tapiador, Francisco J

2017-09-16

Precise modeling of CO 2 emissions is important for environmental research. This paper presents a new model of human population dynamics that can be embedded into ESMs (Earth System Models) to improve climate modeling. Through a system dynamics approach, we develop a cohort-component model that successfully simulates historical population dynamics with fine spatial resolution (about 1°×1°). The population projections are used to improve the estimates of CO 2 emissions, thus transcending the bulk approach of existing models and allowing more realistic non-linear effects to feature in the simulations. The module, dubbed POPEM (from Population Parameterization for Earth Models), is compared with current emission inventories and validated against UN aggregated data. Finally, it is shown that the module can be used to advance toward fully coupling the social and natural components of the Earth system, an emerging research path for environmental science and pollution research.

A model of population dynamics of TB in a prison system and application to South Africa.

PubMed

Witbooi, Peter; Vyambwera, Sibaliwe Maku

2017-11-29

Tuberculosis (TB) continues to spread in South African prisons in particular, as prisons are over-capacitated and have poor ventilation. The awaiting trial detainees are not screened on admission and are at high risk of getting infected with TB. We propose a compartmental model to describe the population dynamics of TB disease in prisons. Our model considers the inflow of susceptible, exposed and TB infectives into the prison population. Removal of individuals out of the prison population can be either by death or by being released from prison, as compared to a general population in which removal is only by death. We describe conditions, including non-inflow of infectives into the prison, which will ensure that TB can be eradicated from the prison population. The model is calibrated for the South African prison system, by using data in existing literature. The model can be used to make quantitative projections of TB prevalence and to measure the effect of interventions. Illustrative simulations in this regard are presented. The model can be used for other prison populations too, if data is available to calculate the model parameters. Various simulations generated with our model serve to illustrate how it can be utilized in making future projections of the levels of prevalence of TB, and to quantify the effect of interventions such as screening, treatment or reduction of transmission parameter values through improved living conditions for inmates. This makes it particularly useful as there are various targets set by the World Health Organization and by governments, for reduction of TB prevalence and ultimately its eradication. Towards eradication of TB from a prison system, the theorem on global stability of the disease-free state is a useful indicator.

Orthogonal Projection in Teaching Regression and Financial Mathematics

ERIC Educational Resources Information Center

Kachapova, Farida; Kachapov, Ilias

2010-01-01

Two improvements in teaching linear regression are suggested. The first is to include the population regression model at the beginning of the topic. The second is to use a geometric approach: to interpret the regression estimate as an orthogonal projection and the estimation error as the distance (which is minimized by the projection). Linear…

Population-Based Analysis and Projections of Liver Supply Under Redistricting.

PubMed

Parikh, Neehar D; Marrero, Wesley J; Sonnenday, Christopher J; Lok, Anna S; Hutton, David W; Lavieri, Mariel S

2017-09-01

To reduce the geographic heterogeneity in liver transplant allocation, the United Network of Organ Sharing has proposed redistricting, which is impacted by both donor supply and liver transplantation demand. We aimed to determine the impact of demographic changes on the redistricting proposal and characterize causes behind geographic heterogeneity in donor supply. We analyzed adult donors from 2002 to 2014 from the United Network of Organ Sharing database and calculated regional liver donation and utilization stratified by age, race, and body mass index. We used US population data to make regional projections of available donors from 2016 to 2025, incorporating the proposed 8-region redistricting plan. We used donors/100 000 population age 18 to 84 years (D/100K) as a measure of equity. We calculated a coefficient of variation (standard deviation/mean) for each regional model. We performed an exploratory analysis where we used national rates of donation, utilization and both for each regional model. The overall projected D/100K will decrease from 2.53 to 2.49 from 2016 to 2025. The coefficient of variation in 2016 is expected to be 20.3% in the 11-region model and 13.2% in the 8-region model. We found that standardizing regional donation and utilization rates would reduce geographic heterogeneity to 4.9% in the 8-region model and 4.6% in the 11-region model. The 8-region allocation model will reduce geographic variation in donor supply to a significant extent; however, we project that geographic disparity will marginally increase over time. Though challenging, interventions to better standardize donation and utilization rates would be impactful in reducing geographic heterogeneity in organ supply.

Design of a digital phantom population for myocardial perfusion SPECT imaging research.

PubMed

Ghaly, Michael; Du, Yong; Fung, George S K; Tsui, Benjamin M W; Links, Jonathan M; Frey, Eric

2014-06-21

Digital phantoms and Monte Carlo (MC) simulations have become important tools for optimizing and evaluating instrumentation, acquisition and processing methods for myocardial perfusion SPECT (MPS). In this work, we designed a new adult digital phantom population and generated corresponding Tc-99m and Tl-201 projections for use in MPS research. The population is based on the three-dimensional XCAT phantom with organ parameters sampled from the Emory PET Torso Model Database. Phantoms included three variations each in body size, heart size, and subcutaneous adipose tissue level, for a total of 27 phantoms of each gender. The SimSET MC code and angular response functions were used to model interactions in the body and the collimator-detector system, respectively. We divided each phantom into seven organs, each simulated separately, allowing use of post-simulation summing to efficiently model uptake variations. Also, we adapted and used a criterion based on the relative Poisson effective count level to determine the required number of simulated photons for each simulated organ. This technique provided a quantitative estimate of the true noise in the simulated projection data, including residual MC simulation noise. Projections were generated in 1 keV wide energy windows from 48-184 keV assuming perfect energy resolution to permit study of the effects of window width, energy resolution, and crosstalk in the context of dual isotope MPS. We have developed a comprehensive method for efficiently simulating realistic projections for a realistic population of phantoms in the context of MPS imaging. The new phantom population and realistic database of simulated projections will be useful in performing mathematical and human observer studies to evaluate various acquisition and processing methods such as optimizing the energy window width, investigating the effect of energy resolution on image quality and evaluating compensation methods for degrading factors such as crosstalk in the context of single and dual isotope MPS.

Projection of temperature-related mortality due to cardiovascular disease in beijing under different climate change, population, and adaptation scenarios.

PubMed

Zhang, Boya; Li, Guoxing; Ma, Yue; Pan, Xiaochuan

2018-04-01

Human health faces unprecedented challenges caused by climate change. Thus, studies of the effect of temperature change on total mortality have been conducted in numerous countries. However, few of those studies focused on temperature-related mortality due to cardiovascular disease (CVD) or considered future population changes and adaptation to climate change. We present herein a projection of temperature-related mortality due to CVD under different climate change, population, and adaptation scenarios in Beijing, a megacity in China. To this end, 19 global circulation models (GCMs), 3 representative concentration pathways (RCPs), 3 socioeconomic pathways, together with generalized linear models and distributed lag non-linear models, were used to project future temperature-related CVD mortality during periods centered around the years 2050 and 2070. The number of temperature-related CVD deaths in Beijing is projected to increase by 3.5-10.2% under different RCP scenarios compared with that during the baseline period. Using the same GCM, the future daily maximum temperatures projected using the RCP2.6, RCP4.5, and RCP8.5 scenarios showed a gradually increasing trend. When population change is considered, the annual rate of increase in temperature-related CVD deaths was up to fivefold greater than that under no-population-change scenarios. The decrease in the number of cold-related deaths did not compensate for the increase in that of heat-related deaths, leading to a general increase in the number of temperature-related deaths due to CVD in Beijing. In addition, adaptation to climate change may enhance rather than ameliorate the effect of climate change, as the increase in cold-related CVD mortality greater than the decrease in heat-related CVD mortality in the adaptation scenarios will result in an increase in the total number of temperature-related CVD mortalities. Copyright © 2018 Elsevier Inc. All rights reserved.

Design of a digital phantom population for myocardial perfusion SPECT imaging research

NASA Astrophysics Data System (ADS)

Ghaly, Michael; Du, Yong; Fung, George S. K.; Tsui, Benjamin M. W.; Links, Jonathan M.; Frey, Eric

2014-06-01

Digital phantoms and Monte Carlo (MC) simulations have become important tools for optimizing and evaluating instrumentation, acquisition and processing methods for myocardial perfusion SPECT (MPS). In this work, we designed a new adult digital phantom population and generated corresponding Tc-99m and Tl-201 projections for use in MPS research. The population is based on the three-dimensional XCAT phantom with organ parameters sampled from the Emory PET Torso Model Database. Phantoms included three variations each in body size, heart size, and subcutaneous adipose tissue level, for a total of 27 phantoms of each gender. The SimSET MC code and angular response functions were used to model interactions in the body and the collimator-detector system, respectively. We divided each phantom into seven organs, each simulated separately, allowing use of post-simulation summing to efficiently model uptake variations. Also, we adapted and used a criterion based on the relative Poisson effective count level to determine the required number of simulated photons for each simulated organ. This technique provided a quantitative estimate of the true noise in the simulated projection data, including residual MC simulation noise. Projections were generated in 1 keV wide energy windows from 48-184 keV assuming perfect energy resolution to permit study of the effects of window width, energy resolution, and crosstalk in the context of dual isotope MPS. We have developed a comprehensive method for efficiently simulating realistic projections for a realistic population of phantoms in the context of MPS imaging. The new phantom population and realistic database of simulated projections will be useful in performing mathematical and human observer studies to evaluate various acquisition and processing methods such as optimizing the energy window width, investigating the effect of energy resolution on image quality and evaluating compensation methods for degrading factors such as crosstalk in the context of single and dual isotope MPS.

A model for evaluating the sustainability of community-directed treatment with ivermectin in the African Program for Onchocerciasis Control.

PubMed

Okeibunor, Joseph; Bump, Jesse; Zouré, Honorat G M; Sékétéli, Azodoga; Godin, Christine; Amazigo, Uche V

2012-01-01

Onchocerciasis is controlled by mass treatment of at-risk populations with ivermectin. Ivermectin is delivered through community-directed treatment (CDTI) approach. A model has been developed to evaluate the sustainability of the approach and has been tested at 35 projects in 10 countries of the African Program for Onchocerciasis Control (APOC). It incorporates quantitative and qualitative data collection and analysis, taking account of two factors identified as crucial to project sustainability. These are (i) the provision of project performance information to partners, and (ii) evidence-based support for project implementation. The model is designed to provide critical indicators of project performance of the model to implementing, coordinating, and funding partners. The model's participatory and flexible nature makes it culturally sensitive and usable by project management. This model is able to analyze the different levels involved in project implementation and arrive at a judgment for the whole project. It has inbuilt mechanisms for ensuring data reliability and validity. The model addresses the complex issue of sustainability with a cross-sectional design focusing on how and at which operational level of implementation to strengthen a CDTI project. The unique attributes and limitations of the model for evaluating the sustainability of projects were described. Copyright © 2012 John Wiley & Sons, Ltd.

Blue Book: EPA Radiogenic Cancer Risk Models and Projections for the U.S. Population

EPA Pesticide Factsheets

This document presents EPA estimates of cancer incidence and mortality risk coefficients pertaining to low dose exposures to ionizing radiation for the U.S. population, as well as their scientific basis.

The Actuarial Society of South Africa AIDS model.

PubMed

1997-01-01

The AIDS Committee of the Actuarial Society of South Africa has developed a demographic model to allow researchers to project the impact of HIV and AIDS in South Africa. The model is available for use as a projection tool rather than to endorse a given projected scenario as being representative. It is very flexible and can be adapted to suit different purposes by anyone with a working knowledge of Microsoft Excel. The need for a model, calibration of the model, the lack of allowance in the model for racial and cultural heterogeneity in the underlying population, and default scenario projections are discussed. The model is available free of charge via E-mail and on the worldwide web at the following respective addresses: awhitelo@oldmutual.com and http://www.und.ac.za/und/eco/eru/eru.htm.

Evaluating models of population process in a threatened population of Steller’s eiders: A retrospective approach

USGS Publications Warehouse

Dunham, Kylee; Grand, James B.

2016-10-11

The Alaskan breeding population of Steller’s eiders (Polysticta stelleri) was listed as threatened under the Endangered Species Act in 1997 in response to perceived declines in abundance throughout their breeding and nesting range. Aerial surveys suggest the breeding population is small and highly variable in number, with zero birds counted in 5 of the last 25 years. Research was conducted to evaluate competing population process models of Alaskan-breeding Steller’s eiders through comparison of model projections to aerial survey data. To evaluate model efficacy and estimate demographic parameters, a Bayesian state-space modeling framework was used and each model was fit to counts from the annual aerial surveys, using sequential importance sampling and resampling. The results strongly support that the Alaskan breeding population experiences population level nonbreeding events and is open to exchange with the larger Russian-Pacific breeding population. Current recovery criteria for the Alaskan breeding population rely heavily on the ability to estimate population viability. The results of this investigation provide an informative model of the population process that can be used to examine future population states and assess the population in terms of the current recovery and reclassification criteria.

Spatially-Explicit Simulation Modeling of Ecological Response to Climate Change: Methodological Considerations in Predicting Shifting Population Dynamics of Infectious Disease Vectors.

PubMed

Dhingra, Radhika; Jimenez, Violeta; Chang, Howard H; Gambhir, Manoj; Fu, Joshua S; Liu, Yang; Remais, Justin V

2013-09-01

Poikilothermic disease vectors can respond to altered climates through spatial changes in both population size and phenology. Quantitative descriptors to characterize, analyze and visualize these dynamic responses are lacking, particularly across large spatial domains. In order to demonstrate the value of a spatially explicit, dynamic modeling approach, we assessed spatial changes in the population dynamics of Ixodes scapularis , the Lyme disease vector, using a temperature-forced population model simulated across a grid of 4 × 4 km cells covering the eastern United States, using both modeled (Weather Research and Forecasting (WRF) 3.2.1) baseline/current (2001-2004) and projected (Representative Concentration Pathway (RCP) 4.5 and RCP 8.5; 2057-2059) climate data. Ten dynamic population features (DPFs) were derived from simulated populations and analyzed spatially to characterize the regional population response to current and future climate across the domain. Each DPF under the current climate was assessed for its ability to discriminate observed Lyme disease risk and known vector presence/absence, using data from the US Centers for Disease Control and Prevention. Peak vector population and month of peak vector population were the DPFs that performed best as predictors of current Lyme disease risk. When examined under baseline and projected climate scenarios, the spatial and temporal distributions of DPFs shift and the seasonal cycle of key questing life stages is compressed under some scenarios. Our results demonstrate the utility of spatial characterization, analysis and visualization of dynamic population responses-including altered phenology-of disease vectors to altered climate.

Spatially-Explicit Simulation Modeling of Ecological Response to Climate Change: Methodological Considerations in Predicting Shifting Population Dynamics of Infectious Disease Vectors

PubMed Central

Dhingra, Radhika; Jimenez, Violeta; Chang, Howard H.; Gambhir, Manoj; Fu, Joshua S.; Liu, Yang; Remais, Justin V.

2014-01-01

Poikilothermic disease vectors can respond to altered climates through spatial changes in both population size and phenology. Quantitative descriptors to characterize, analyze and visualize these dynamic responses are lacking, particularly across large spatial domains. In order to demonstrate the value of a spatially explicit, dynamic modeling approach, we assessed spatial changes in the population dynamics of Ixodes scapularis, the Lyme disease vector, using a temperature-forced population model simulated across a grid of 4 × 4 km cells covering the eastern United States, using both modeled (Weather Research and Forecasting (WRF) 3.2.1) baseline/current (2001–2004) and projected (Representative Concentration Pathway (RCP) 4.5 and RCP 8.5; 2057–2059) climate data. Ten dynamic population features (DPFs) were derived from simulated populations and analyzed spatially to characterize the regional population response to current and future climate across the domain. Each DPF under the current climate was assessed for its ability to discriminate observed Lyme disease risk and known vector presence/absence, using data from the US Centers for Disease Control and Prevention. Peak vector population and month of peak vector population were the DPFs that performed best as predictors of current Lyme disease risk. When examined under baseline and projected climate scenarios, the spatial and temporal distributions of DPFs shift and the seasonal cycle of key questing life stages is compressed under some scenarios. Our results demonstrate the utility of spatial characterization, analysis and visualization of dynamic population responses—including altered phenology—of disease vectors to altered climate. PMID:24772388

An Adaptation Dilemma Caused by Impacts-Modeling Uncertainty

NASA Astrophysics Data System (ADS)

Frieler, K.; Müller, C.; Elliott, J. W.; Heinke, J.; Arneth, A.; Bierkens, M. F.; Ciais, P.; Clark, D. H.; Deryng, D.; Doll, P. M.; Falloon, P.; Fekete, B. M.; Folberth, C.; Friend, A. D.; Gosling, S. N.; Haddeland, I.; Khabarov, N.; Lomas, M. R.; Masaki, Y.; Nishina, K.; Neumann, K.; Oki, T.; Pavlick, R.; Ruane, A. C.; Schmid, E.; Schmitz, C.; Stacke, T.; Stehfest, E.; Tang, Q.; Wisser, D.

2013-12-01

Ensuring future well-being for a growing population under either strong climate change or an aggressive mitigation strategy requires a subtle balance of potentially conflicting response measures. In the case of competing goals, uncertainty in impact estimates plays a central role when high confidence in achieving a primary objective (such as food security) directly implies an increased probability of uncertainty induced failure with regard to a competing target (such as climate protection). We use cross sectoral consistent multi-impact model simulations from the Inter-Sectoral Impact Model Intercomparison Project (ISI-MIP, www.isi-mip.org) to illustrate this uncertainty dilemma: RCP projections from 7 global crop, 11 hydrological, and 7 biomes models are combined to analyze irrigation and land use changes as possible responses to climate change and increasing crop demand due to population growth and economic development. We show that - while a no-regrets option with regard to climate protection - additional irrigation alone is not expected to balance the demand increase by 2050. In contrast, a strong expansion of cultivated land closes the projected production-demand gap in some crop models. However, it comes at the expense of a loss of natural carbon sinks of order 50%. Given the large uncertainty of state of the art crop model projections even these strong land use changes would not bring us ';on the safe side' with respect to food supply. In a world where increasing carbon emissions continue to shrink the overall solution space, we demonstrate that current impacts-modeling uncertainty is a luxury we cannot afford. ISI-MIP is intended to provide cross sectoral consistent impact projections for model intercomparison and improvement as well as cross-sectoral integration. The results presented here were generated within the first Fast-Track phase of the project covering global impact projections. The second phase will also include regional projections. It is the aim of the project to build up a CMIP like open archive for climate impact projections allowing for the necessary sharpening the our picture of a 1,2,3,4 degrees warmer world.

Metapopulation dynamics of a Burrowing Owl (Speotyto cunicularia) population in Colorado

Treesearch

R. Scott Lutz; David L. Plumpton

1997-01-01

We banded 555 Burrowing Owls (Speotyto cunicularia) either as adults (after hatch year; AHY) or as young of the year (hatch year; HY) and used capture-recapture models to estimate survival and recapture rates and Leslie matrix models to project population growth over time at the 6,900-ha Rocky Mountain Arsenal National Wildlife Refuge (RMANWR),...

Fishery management priorities vary with self‐recruitment in sedentary marine populations.

PubMed

Yau, Annie J; Lenihan, Hunter S; Kendall, Bruce E

Fisheries science often uses population models that assume no external recruitment, but nearshore marine populations harvested on small scales of <200 km often exhibit an unknown mix of self-recruitment and recruitment from external sources. Since empirical determination of self-recruitment vs. external recruitment is difficult, we used a modeling approach to examine the sensitivity of fishery management priorities to recruitment assumptions (self [closed], external [open]) in a local population of harvested giant clams (Tridacna maxima) on Mo'orea, French Polynesia. From 2006 to 2010, we measured growth, fecundity, recruitment, and survival (resulting from natural and fishing mortality). We used these data to parameterize both a closed (complete self-recruitment) and an open (no self-recruitment) integral projection model (IPM), and then calculated elasticities of demographic rates (growth, survival, recruitment) to future population abundance in 20 years. The models' lowest projected abundance was 93.4% (95% CI, [86.5%, 101.8%]) of present abundance, if the local population is entirely open and the present level of fishing mortality persists. The population will exhibit self-sustaining dynamics (1 ≤ λ ≤ 1.07) as for a closed population if the ratio of self-recruits per gram of dry gonad is >0.775 (equivalent to 52.85% self-recruitment under present conditions). Elasticity analysis of demographic parameters indicated that future abundance can most effectively be influenced by increasing survival of mid-sized clams (∼80–120 mm) if the population is self-sustaining, and by increasing survival of juvenile clams (∼40–70 mm) if the population is non-self-sustaining (as for an open population). Our results illustrate that management priorities can vary depending on the amount of self-recruitment in a local population.

The Ottawa Citizen Engagement and Action Model (OCEAM): A Citizen engagement Strategy Operationalized Through The Participatory Research in Ottawa, Management and Point-of-care of Tobacco (PROMPT) Study: A Community Based Participatory Action Research Project in Inner City Ottawa.

PubMed

Pakhale, Smita; Kaur, Tina; Florence, Kelly; Rose, Tiffany; Boyd, Robert; Haddad, Joanne; Pettey, Donna; Muckle, Wendy; Tyndall, Mark

2016-01-01

The PROMPT study is a community-based research project designed to understand the factors which affect smoking as well as ways to manage, reduce and quit smoking among people who use drugs in Ottawa. There is strong medical evidence that smoking tobacco is related to more than two dozen diseases and conditions. Smoking tobacco remains the leading cause of preventable death and has negative health impacts on people of all ages. Although Ottawa has one of the lowest smoking rates in Ontario (12 %), major differences exist, with approximately a 96 % smoking rate among those who use drugs in the city of Ottawa. To address this inequity, we recruited and trained four community research peers who were representative of the study target population (ex- or currently homeless, insecurely housed or multi-drug users). We designed the ten-step Ottawa Citizen Engagement and Action Model (OCEAM) for the PROMPT study. In this paper we have described this process in a step-by-step fashion, as used in the PROMPT study. The eighty PROMPT participants are being followed for six months and are being provided with free and off-label Nicotine Replacement Therapy (NRT). Objectives The PROMPT study, Participatory Research in Ottawa, Management and Point-of-care of Tobacco, is a prospective cohort study which utilizes community-based participation and social network-based approaches to address tobacco dependence in inner city Ottawa. The project was designed to: facilitate retention of participants; to understand the barriers and facilitators of smoking; optimize ways to manage, reduce, and quit tobacco use among people who use drugs in Ottawa, Canada. The purpose of this paper is to describe the processes utilized in citizen or patient engagement in academic research, through our tobacco dependence management project in the inner city population in Ottawa, Canada. Background Tobacco smoking is inequitably distributed in Canada with rates at 12 % in Ottawa, as compared to 18 % in rest of Canada. However, the PROUD Study (Participatory Research in Ottawa: Understanding Drugs) demonstrated that 96 % of the inner city population, of Ottawa currently smoke tobacco. This distinct inequity in tobacco use translates into inequitable distribution of health outcomes, such morbidity and mortality in this population. Consequently, a community-based participatory, peer-led research project was conducted in the inner city population of Ottawa. Methods We recruited and trained four community research peers who were representative of the study target population. We conceived, designed and operationalized the ten-step Ottawa Citizen Engagement and Action Model (OCEAM) for the PROMPT study. The peers have co-led all aspects of the project from conceptualizing the study question to participating in knowledge translation. Each step of the project had defined objectives and outcome measures. Discussion The involvement of peers in recruitment ensured representation of tobacco and drug users-individuals truly representative of the intended target population. Peer, participant engagement and trust was established from the conception of the project. For historical and self-evident reasons, trust and engagement is rarely found in this population. Peers successfully participated in all ten steps of the Citizen Engagement and Action model. The PROMPT study utilized the CBPR (Community Based Participatory research) approach to encourage engagement and build trust in a difficult to reach and hard to treat, inner city population. The ten-step OCEAM model was conceived, designed and operationalized and the PROMPT study will continue to follow the eighty PROMPT participants for six months to understand the optimal ways to manage, reduce, and quit smoking within an inner city population.

A high resolution spatial population database of Somalia for disease risk mapping.

PubMed

Linard, Catherine; Alegana, Victor A; Noor, Abdisalan M; Snow, Robert W; Tatem, Andrew J

2010-09-14

Millions of Somali have been deprived of basic health services due to the unstable political situation of their country. Attempts are being made to reconstruct the health sector, in particular to estimate the extent of infectious disease burden. However, any approach that requires the use of modelled disease rates requires reasonable information on population distribution. In a low-income country such as Somalia, population data are lacking, are of poor quality, or become outdated rapidly. Modelling methods are therefore needed for the production of contemporary and spatially detailed population data. Here land cover information derived from satellite imagery and existing settlement point datasets were used for the spatial reallocation of populations within census units. We used simple and semi-automated methods that can be implemented with free image processing software to produce an easily updatable gridded population dataset at 100 × 100 meters spatial resolution. The 2010 population dataset was matched to administrative population totals projected by the UN. Comparison tests between the new dataset and existing population datasets revealed important differences in population size distributions, and in population at risk of malaria estimates. These differences are particularly important in more densely populated areas and strongly depend on the settlement data used in the modelling approach. The results show that it is possible to produce detailed, contemporary and easily updatable settlement and population distribution datasets of Somalia using existing data. The 2010 population dataset produced is freely available as a product of the AfriPop Project and can be downloaded from: http://www.afripop.org.

A high resolution spatial population database of Somalia for disease risk mapping

PubMed Central

2010-01-01

Background Millions of Somali have been deprived of basic health services due to the unstable political situation of their country. Attempts are being made to reconstruct the health sector, in particular to estimate the extent of infectious disease burden. However, any approach that requires the use of modelled disease rates requires reasonable information on population distribution. In a low-income country such as Somalia, population data are lacking, are of poor quality, or become outdated rapidly. Modelling methods are therefore needed for the production of contemporary and spatially detailed population data. Results Here land cover information derived from satellite imagery and existing settlement point datasets were used for the spatial reallocation of populations within census units. We used simple and semi-automated methods that can be implemented with free image processing software to produce an easily updatable gridded population dataset at 100 × 100 meters spatial resolution. The 2010 population dataset was matched to administrative population totals projected by the UN. Comparison tests between the new dataset and existing population datasets revealed important differences in population size distributions, and in population at risk of malaria estimates. These differences are particularly important in more densely populated areas and strongly depend on the settlement data used in the modelling approach. Conclusions The results show that it is possible to produce detailed, contemporary and easily updatable settlement and population distribution datasets of Somalia using existing data. The 2010 population dataset produced is freely available as a product of the AfriPop Project and can be downloaded from: http://www.afripop.org. PMID:20840751

DOE Office of Scientific and Technical Information (OSTI.GOV)

Valin, Hugo; Sands, Ronald; van der Mensbrugghe, Dominique

Understanding the capacity of agricultural systems to feed the world population under climate change requires a good prospective vision on the future development of food demand. This paper reviews modeling approaches from ten global economic models participating to the AgMIP project, in particular the demand function chosen and the set of parameters used. We compare food demand projections at the horizon 2050 for various regions and agricultural products under harmonized scenarios. Depending on models, we find for a business as usual scenario (SSP2) an increase in food demand of 59-98% by 2050, slightly higher than FAO projection (54%). The prospectivemore » for animal calories is particularly uncertain with a range of 61-144%, whereas FAO anticipates an increase by 76%. The projections reveal more sensitive to socio-economic assumptions than to climate change conditions or bioenergy development. When considering a higher population lower economic growth world (SSP3), consumption per capita drops by 9% for crops and 18% for livestock. Various assumptions on climate change in this exercise do not lead to world calorie losses greater than 6%. Divergences across models are however notable, due to differences in demand system, income elasticities specification, and response to price change in the baseline.« less

Alzheimer's and other dementias in Canada, 2011 to 2031: a microsimulation Population Health Modeling (POHEM) study of projected prevalence, health burden, health services, and caregiving use.

PubMed

Manuel, Douglas G; Garner, Rochelle; Finès, Philippe; Bancej, Christina; Flanagan, William; Tu, Karen; Reimer, Kim; Chambers, Larry W; Bernier, Julie

2016-01-01

Worldwide, there is concern that increases in the prevalence of dementia will result in large demands for caregivers and supportive services that will be challenging to address. Previous dementia projections have either been simple extrapolations of prevalence or macrosimulations based on dementia incidence. A population-based microsimulation model of Alzheimer's and related dementias (POHEM:Neurological) was created using Canadian demographic data, estimates of dementia incidence, health status (health-related quality of life and mortality risk), health care costs and informal caregiving use. Dementia prevalence and 12 other measures were projected to 2031. Between 2011 and 2031, there was a projected two-fold increase in the number of people living with dementia in Canada (1.6-fold increase in prevalence rate). By 2031, the projected informal (unpaid) caregiving for dementia in Canada was two billion hours per year, or 100 h per year per Canadian of working age. The projected increase in dementia prevalence was largely related to the expected increase in older Canadians, with projections sensitive to changes in the age of dementia onset.

DATA FOR ENVIRONMENTAL MODELING: AN OVERVIEW

EPA Science Inventory

The objective of the project described here, entitled Data for Environmental Modeling (D4EM), is the development of a comprehensive set of software tools that allow an environmental model developer to automatically populate model input files with environmental data available from...

Intraspecific niche models for ponderosa pine (Pinus ponderosa) suggest potential variability in population-level response to climate change.

PubMed

Maguire, Kaitlin C; Shinneman, Douglas J; Potter, Kevin M; Hipkins, Valerie D

2018-03-14

Unique responses to climate change can occur across intraspecific levels, resulting in individualistic adaptation or movement patterns among populations within a given species. Thus, the need to model potential responses among genetically distinct populations within a species is increasingly recognized. However, predictive models of future distributions are regularly fit at the species level, often because intraspecific variation is unknown or is identified only within limited sample locations. In this study, we considered the role of intraspecific variation to shape the geographic distribution of ponderosa pine (Pinus ponderosa), an ecologically and economically important tree species in North America. Morphological and genetic variation across the distribution of ponderosa pine suggest the need to model intraspecific populations: the two varieties (var. ponderosa and var. scopulorum) and several haplotype groups within each variety have been shown to occupy unique climatic niches, suggesting populations have distinct evolutionary lineages adapted to different environmental conditions. We utilized a recently-available, geographically-widespread dataset of intraspecific variation (haplotypes) for ponderosa pine and a recently-devised lineage distance modeling approach to derive additional, likely intraspecific occurrence locations. We confirmed the relative uniqueness of each haplotype-climate relationship using a niche-overlap analysis, and developed ecological niche models (ENMs) to project the distribution for two varieties and eight haplotypes under future climate forecasts. Future projections of haplotype niche distributions generally revealed greater potential range loss than predicted for the varieties. This difference may reflect intraspecific responses of distinct evolutionary lineages. However, directional trends are generally consistent across intraspecific levels, and include a loss of distributional area and an upward shift in elevation. Our results demonstrate the utility in modeling intraspecific response to changing climate and they inform management and conservation strategies, by identifying haplotypes and geographic areas that may be most at risk, or most secure, under projected climate change.

Intraspecific niche models for ponderosa pine (Pinus ponderosa) suggest potential variability in population-level response to climate change

USGS Publications Warehouse

Maguire, Kaitlin C.; Shinneman, Douglas; Potter, Kevin M.; Hipkins, Valerie D.

2018-01-01

Unique responses to climate change can occur across intraspecific levels, resulting in individualistic adaptation or movement patterns among populations within a given species. Thus, the need to model potential responses among genetically distinct populations within a species is increasingly recognized. However, predictive models of future distributions are regularly fit at the species level, often because intraspecific variation is unknown or is identified only within limited sample locations. In this study, we considered the role of intraspecific variation to shape the geographic distribution of ponderosa pine (Pinus ponderosa), an ecologically and economically important tree species in North America. Morphological and genetic variation across the distribution of ponderosa pine suggest the need to model intraspecific populations: the two varieties (var. ponderosa and var. scopulorum) and several haplotype groups within each variety have been shown to occupy unique climatic niches, suggesting populations have distinct evolutionary lineages adapted to different environmental conditions. We utilized a recently-available, geographically-widespread dataset of intraspecific variation (haplotypes) for ponderosa pine and a recently-devised lineage distance modeling approach to derive additional, likely intraspecific occurrence locations. We confirmed the relative uniqueness of each haplotype-climate relationship using a niche-overlap analysis, and developed ecological niche models (ENMs) to project the distribution for two varieties and eight haplotypes under future climate forecasts. Future projections of haplotype niche distributions generally revealed greater potential range loss than predicted for the varieties. This difference may reflect intraspecific responses of distinct evolutionary lineages. However, directional trends are generally consistent across intraspecific levels, and include a loss of distributional area and an upward shift in elevation. Our results demonstrate the utility in modeling intraspecific response to changing climate and they inform management and conservation strategies, by identifying haplotypes and geographic areas that may be most at risk, or most secure, under projected climate change.

Generating a Dynamic Synthetic Population – Using an Age-Structured Two-Sex Model for Household Dynamics

PubMed Central

Namazi-Rad, Mohammad-Reza; Mokhtarian, Payam; Perez, Pascal

2014-01-01

Generating a reliable computer-simulated synthetic population is necessary for knowledge processing and decision-making analysis in agent-based systems in order to measure, interpret and describe each target area and the human activity patterns within it. In this paper, both synthetic reconstruction (SR) and combinatorial optimisation (CO) techniques are discussed for generating a reliable synthetic population for a certain geographic region (in Australia) using aggregated- and disaggregated-level information available for such an area. A CO algorithm using the quadratic function of population estimators is presented in this paper in order to generate a synthetic population while considering a two-fold nested structure for the individuals and households within the target areas. The baseline population in this study is generated from the confidentialised unit record files (CURFs) and 2006 Australian census tables. The dynamics of the created population is then projected over five years using a dynamic micro-simulation model for individual- and household-level demographic transitions. This projection is then compared with the 2011 Australian census. A prediction interval is provided for the population estimates obtained by the bootstrapping method, by which the variability structure of a predictor can be replicated in a bootstrap distribution. PMID:24733522

An answer to chronicity in the Basque Country: primary care-based population health management.

PubMed

Nuño-Solinís, Roberto; Orueta, Juan F; Mateos, Maider

2012-01-01

Chronic conditions have an impact on individuals since they represent a restraint on quality of life, functional status, and productivity of people who suffer from them but they also compromise the sustainability of health systems. In 2010, the Strategy for Tackling the Challenge of Chronicity in the Basque Country was published. It contains policies and projects aimed at reinventing the health delivery model with the purpose of improving the quality of care for chronic patients and advancing toward a more sustainable, proactive, and integrated model. We present 3 projects here: population stratification, integrated care initiatives, and innovation from health care staff.

Efficient coarse simulation of a growing avascular tumor

PubMed Central

Kavousanakis, Michail E.; Liu, Ping; Boudouvis, Andreas G.; Lowengrub, John; Kevrekidis, Ioannis G.

2013-01-01

The subject of this work is the development and implementation of algorithms which accelerate the simulation of early stage tumor growth models. Among the different computational approaches used for the simulation of tumor progression, discrete stochastic models (e.g., cellular automata) have been widely used to describe processes occurring at the cell and subcell scales (e.g., cell-cell interactions and signaling processes). To describe macroscopic characteristics (e.g., morphology) of growing tumors, large numbers of interacting cells must be simulated. However, the high computational demands of stochastic models make the simulation of large-scale systems impractical. Alternatively, continuum models, which can describe behavior at the tumor scale, often rely on phenomenological assumptions in place of rigorous upscaling of microscopic models. This limits their predictive power. In this work, we circumvent the derivation of closed macroscopic equations for the growing cancer cell populations; instead, we construct, based on the so-called “equation-free” framework, a computational superstructure, which wraps around the individual-based cell-level simulator and accelerates the computations required for the study of the long-time behavior of systems involving many interacting cells. The microscopic model, e.g., a cellular automaton, which simulates the evolution of cancer cell populations, is executed for relatively short time intervals, at the end of which coarse-scale information is obtained. These coarse variables evolve on slower time scales than each individual cell in the population, enabling the application of forward projection schemes, which extrapolate their values at later times. This technique is referred to as coarse projective integration. Increasing the ratio of projection times to microscopic simulator execution times enhances the computational savings. Crucial accuracy issues arising for growing tumors with radial symmetry are addressed by applying the coarse projective integration scheme in a cotraveling (cogrowing) frame. As a proof of principle, we demonstrate that the application of this scheme yields highly accurate solutions, while preserving the computational savings of coarse projective integration. PMID:22587128

Joint Probabilistic Projection of Female and Male Life Expectancy

PubMed Central

Raftery, Adrian E.; Lalic, Nevena; Gerland, Patrick

2014-01-01

BACKGROUND The United Nations (UN) produces population projections for all countries every two years. These are used by international organizations, governments, the private sector and researchers for policy planning, for monitoring development goals, as inputs to economic and environmental models, and for social and health research. The UN is considering producing fully probabilistic population projections, for which joint probabilistic projections of future female and male life expectancy at birth are needed. OBJECTIVE We propose a methodology for obtaining joint probabilistic projections of female and male life expectancy at birth. METHODS We first project female life expectancy using a one-sex method for probabilistic projection of life expectancy. We then project the gap between female and male life expectancy. We propose an autoregressive model for the gap in a future time period for a particular country, which is a function of female life expectancy and a t-distributed random perturbation. This method takes into account mortality data limitations, is comparable across countries, and accounts for shocks. We estimate all parameters based on life expectancy estimates for 1950–2010. The methods are implemented in the bayesLife and bayesPop R packages. RESULTS We evaluated our model using out-of-sample projections for the period 1995–2010, and found that our method performed better than several possible alternatives. CONCLUSIONS We find that the average gap between female and male life expectancy has been increasing for female life expectancy below 75, and decreasing for female life expectancy above 75. Our projections of the gap are lower than the UN’s 2008 projections for most countries and so lead to higher projections of male life expectancy. PMID:25580082

Models for estimating and projecting global, regional and national prevalence and disease burden of asthma: protocol for a systematic review.

PubMed

Bhuia, Mohammad Romel; Nwaru, Bright I; Weir, Christopher J; Sheikh, Aziz

2017-05-17

Models that have so far been used to estimate and project the prevalence and disease burden of asthma are in most cases inadequately described and irreproducible. We aim systematically to describe and critique the existing models in relation to their strengths, limitations and reproducibility, and to determine the appropriate models for estimating and projecting the prevalence and disease burden of asthma. We will search the following electronic databases to identify relevant literature published from 1980 to 2017: Medline, Embase, WHO Library and Information Services and Web of Science Core Collection. We will identify additional studies by searching the reference list of all the retrieved papers and contacting experts. We will include observational studies that used models for estimating and/or projecting prevalence and disease burden of asthma regarding human population of any age and sex. Two independent reviewers will assess the studies for inclusion and extract data from included papers. Data items will include authors' names, publication year, study aims, data source and time period, study population, asthma outcomes, study methodology, model type, model settings, study variables, methods of model derivation, methods of parameter estimation and/or projection, model fit information, key findings and identified research gaps. A detailed critical narrative synthesis of the models will be undertaken in relation to their strengths, limitations and reproducibility. A quality assessment checklist and scoring framework will be used to determine the appropriate models for estimating and projecting the prevalence anddiseaseburden of asthma. We will not collect any primary data for this review, and hence there is no need for formal National Health Services Research Ethics Committee approval. We will present our findings at scientific conferences and publish the findings in the peer-reviewed scientific journal. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2017. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

Stage-Structured Population Dynamics of AEDES AEGYPTI

NASA Astrophysics Data System (ADS)

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.

Chapter 37: Population Trends of the Marbled Murrelet Projected From Demographic Analyses

Treesearch

Steven B. Beissinger

1995-01-01

A demographic model of the Marbled Murrelet is developed to explore likely population trends and factors influencing them. The model was structured to use field data on juvenile ratios, collected near the end of the breeding season and corrected for date of census, to estimate fecundity. Survivorship was estimated for the murrelet based on comparative analyses of...

Demographic projection of high-elevation white pines infected with white pine blister rust: a nonlinear disease model

Treesearch

S. G. Field; A. W. Schoettle; J. G. Klutsch; S. J. Tavener; M. F. Antolin

2012-01-01

Matrix population models have long been used to examine and predict the fate of threatened populations. However, the majority of these efforts concentrate on long-term equilibrium dynamics of linear systems and their underlying assumptions and, therefore, omit the analysis of transience. Since management decisions are typically concerned with the short term (

Forecasting domestic water demand in the Haihe river basin under changing environment

NASA Astrophysics Data System (ADS)

Wang, Xiao-Jun; Zhang, Jian-Yun; Shahid, Shamsuddin; Xie, Yu-Xuan; Zhang, Xu

2018-02-01

A statistical model has been developed for forecasting domestic water demand in Haihe river basin of China due to population growth, technological advances and climate change. Historical records of domestic water use, climate, population and urbanization are used for the development of model. An ensemble of seven general circulation models (GCMs) namely, BCC-CSM1-1, BNU-ESM, CNRM-CM5, GISS-E2-R, MIROC-ESM, PI-ESM-LR, MRI-CGCM3 were used for the projection of climate and the changes in water demand in the Haihe River basin under Representative Concentration Pathways (RCPs) 4.5. The results showed that domestic water demand in different sub-basins of the Haihe river basin will gradually increase due to continuous increase of population and rise in temperature. It is projected to increase maximum 136.22 × 108 m3 by GCM BNU-ESM and the minimum 107.25 × 108 m3 by CNRM-CM5 in 2030. In spite of uncertainty in projection, it can be remarked that climate change and population growth would cause increase in water demand and consequently, reduce the gap between water supply and demand, which eventually aggravate the condition of existing water stress in the basin. Water demand management should be emphasized for adaptation to ever increasing water demand and mitigation of the impacts of environmental changes.

Modeling of Regional Climate Change Effects on Ground-Level Ozone and Childhood Asthma

PubMed Central

Sheffield, Perry E.; Knowlton, Kim; Carr, Jessie L.; Kinney, Patrick L.

2011-01-01

Background The adverse respiratory effects of ground-level ozone are well-established. Ozone is the air pollutant most consistently projected to increase under future climate change. Purpose To project future pediatric asthma emergency department visits associated with ground-level ozone changes, comparing 1990s to 2020s. Methods This study assessed future numbers of asthma emergency department visits for children aged 0–17 years using (1) baseline New York City metropolitan area emergency department rates, (2) a dose–response relationship between ozone levels and pediatric asthma emergency department visits, and (3) projected daily 8-hour maximum ozone concentrations for the 2020s as simulated by a global-to-regional climate change and atmospheric chemistry model. Sensitivity analyses included population projections and ozone precursor changes. This analysis occurred in 2010. Results In this model, climate change could cause an increase in regional summer ozone-related asthma emergency department visits for children aged 0–17 years of 7.3% across the New York City metropolitan region by the 2020s. This effect diminished with inclusion of ozone precursor changes. When population growth is included, the projections of morbidity related to ozone are even larger. Conclusions The results of this analysis demonstrate that the use of regional climate and atmospheric chemistry models make possible the projection of local climate change health effects for specific age groups and specific disease outcomes – such as emergency department visits for asthma. Efforts should be made to improve on this type of modeling to inform local and wider-scale climate change mitigation and adaptation policy. PMID:21855738

A Population Consequence of Acoustic Disturbance Model for Cuviers beaked whale (Ziphius cavirostris) in Southern California

DTIC Science & Technology

2015-09-30

two sources. The energetics model that will underpin both PCoD models for Md and Zc has also been published (New et al 2013). The full PCoD model...to Zc on SCORE. We will also be able to use the simplified PCoD model for beaked whales currently being developed under the ONR-funded project...34Using an interim PCoD protocol to assess the effects of disturbance associated with US Navy exercises on marine mammal populations”. This project will

Gunnison sage-grouse lek site suitability modeling

USGS Publications Warehouse

Ouren, Douglas S.; Ignizio, Drew A.; Siders, Melissa; Childers, Theresa; Tucker, Karen; Seward, Nathan

2014-01-01

In order to better understand and protect species with minimal or decreasing populations, it is imperative to determine their actual existing population size. The focal species for this project is the Gunnison sage-grouse (GUSG), which became a proposed endangered species under the Endangered Species Act, thus confirming the need for better population estimates. Lek site counting during mating season has historically been the primary method for estimating population size since the grouse are very difficult to count at other times of the year. The objective of this project was to use historical data and available technology to identify additional potential lekking sites. This was done by determining areas throughout the study area that have the same landscape characteristics as those where known lekking activities occur. More accurate population counts could be the outcome of locating more lek sites. One of the remaining seven GUSG populations, the Crawford population (estimated at 128 individuals) exists in an area that includes the Gunnison Gorge National Conservation Area and the northern portion of the Black Canyon of the Gunnison National Park (our study area). While the Crawford population is small, it is still considered a self-sustaining population; the persistence and growth of this population directly contribute to genetic diversity conservation of this declining species. To date, only observational and anecdotal information about the Crawford population’s range, movements, and seasonal habitat use exist. From 1978 to the present, GUSG population monitoring has been accomplished through annual lek counts conducted each spring during GUSG mating season. Although this method has provided information on GUSG population trends, it is somewhat limited because counts are based only on known lekking sites and historically minimal efforts have been made to identify additional lek sites. To meet the objective of locating more potential lekking sites, we used a suite of spatial data, geographic information system tools, and maximum entropy species distribution tools. Based on expert knowledge and landscape variables, the modeling process evolved into a hybrid approach for delineating areas that would have a significant probability for supporting GUSG lekking activities. Based on model results, a sampling protocol was developed for model verification. The results of this project provide wildlife managers with a more sophisticated methodology to evaluate GUSG habitat for potential lekking sites.

0-6766 : a generic mode choice model applicable for small and medium-sized MPOs : [project summary].

DOT National Transportation Integrated Search

2013-12-01

Due to the projected population growth increase : in Texas and the continued increase in total : motorized vehicle miles traveled in Texas, the : Texas Department of Transportation (TxDOT) is : interested in examining multimodal solutions to : aid in...

VETPOP2001 ADJ

EPA Science Inventory

VetPop2001Adj is VA's new official estimate and projection of the veteran population as of 9-30-02. It revises and replaces the estimate and projection in VetPop2001. Mathematica has been actively involved since 1998 in designing and developing an actuarial model, VetPop2001 that...

Project-induced displacement, secondary stressors, and health.

PubMed

Cao, Yue; Hwang, Sean-Shong; Xi, Juan

2012-04-01

It has been estimated that about 15 million people are displaced by development projects around the world each year. Despite the magnitude of people affected, research on the health and other impacts of project-induced displacement is rare. This study extends existing knowledge by exploring the short-term health impact of a large scale population displacement resulting from China's Three Gorges Dam Project. The study is theoretically guided by the stress process model, but we supplement it with Cernea's impoverishment risks and reconstruction (IRR) model widely used in displacement literature. Our panel analysis indicates that the displacement is associated positively with relocatees' depression level, and negatively with their self-rated health measured against a control group. In addition, a path analysis suggests that displacement also affects depression and self-rated health indirectly by changing social integration, socioeconomic status, and community resources. The importance of social integration as a protective mechanism, a factor that has been overlooked in past studies of population displacement, is highlighted in this study. Published by Elsevier Ltd.

PROJECT-INDUCED DISPLACEMENT, SECONDARY STRESSORS, AND HEALTH

PubMed Central

Cao, Yue; Hwang, Sean-Shong; Xi, Juan

2012-01-01

It has been estimated that about 15 million people are displaced by development projects around the world each year. Despite the magnitude of people affected, research on the health and other impacts of project-induced displacement is rare. This study extends existing knowledge by exploring the short-term health impact of a large scale population displacement resulting from China’s Three Gorges Dam Project. The study is theoretically guided by the stress process model, but we supplement it with Cernea’s Impoverishment Risks and Reconstruction (IRR) model widely used in displacement literature. Our panel analysis indicates that the displacement is associated positively with relocatees’ depression level, and negatively with their self-rated health measured against a control group. In addition, a path analysis suggests that displacement also affects depression and self-rated health indirectly by changing social integration, socioeconomic status, and community resources. The importance of social integration as a protective mechanism, a factor that has been overlooked in past studies of population displacement, is highlighted in this study. PMID:22341203

Linking climate change projections for an Alaskan watershed to future coho salmon production.

PubMed

Leppi, Jason C; Rinella, Daniel J; Wilson, Ryan R; Loya, Wendy M

2014-06-01

Climate change is predicted to dramatically change hydrologic processes across Alaska, but estimates of how these impacts will influence specific watersheds and aquatic species are lacking. Here, we linked climate, hydrology, and habitat models within a coho salmon (Oncorhynchus kisutch) population model to assess how projected climate change could affect survival at each freshwater life stage and, in turn, production of coho salmon smolts in three subwatersheds of the Chuitna (Chuit) River watershed, Alaska. Based on future climate scenarios and projections from a three-dimensional hydrology model, we simulated coho smolt production over a 20-year span at the end of the century (2080-2100). The direction (i.e., positive vs. negative) and magnitude of changes in smolt production varied substantially by climate scenario and subwatershed. Projected smolt production decreased in all three subwatersheds under the minimum air temperature and maximum precipitation scenario due to elevated peak flows and a resulting 98% reduction in egg-to-fry survival. In contrast, the maximum air temperature and minimum precipitation scenario led to an increase in smolt production in all three subwatersheds through an increase in fry survival. Other climate change scenarios led to mixed responses, with projected smolt production increasing and decreasing in different subwatersheds. Our analysis highlights the complexity inherent in predicting climate-change-related impacts to salmon populations and demonstrates that population effects may depend on interactions between the relative magnitude of hydrologic and thermal changes and their interactions with features of the local habitat. © 2013 The Authors. Global Change Biology published by John Wiley & Sons Ltd.

Development of a Web-Accessible Population Pharmacokinetic Service—Hemophilia (WAPPS-Hemo): Study Protocol

PubMed Central

Foster, Gary; Navarro-Ruan, Tamara; McEneny-King, Alanna; Edginton, Andrea N; Thabane, Lehana

2016-01-01

Background Individual pharmacokinetic assessment is a critical component of tailored prophylaxis for hemophilia patients. Population pharmacokinetics allows using individual sparse data, thus simplifying individual pharmacokinetic studies. Implementing population pharmacokinetics capacity for the hemophilia community is beyond individual reach and requires a system effort. Objective The Web-Accessible Population Pharmacokinetic Service—Hemophilia (WAPPS-Hemo) project aims to assemble a database of patient pharmacokinetic data for all existing factor concentrates, develop and validate population pharmacokinetics models, and integrate these models within a Web-based calculator for individualized pharmacokinetic estimation in patients at participating treatment centers. Methods Individual pharmacokinetic studies on factor VIII and IX concentrates will be sourced from pharmaceutical companies and independent investigators. All factor concentrate manufacturers, hemophilia treatment centers (HTCs), and independent investigators (identified via a systematic review of the literature) having on file pharmacokinetic data and willing to contribute full or sparse pharmacokinetic data will be eligible for participation. Multicompartmental modeling will be performed using a mixed-model approach for derivation and Bayesian forecasting for estimation of individual sparse data. NONMEM (ICON Development Solutions) will be used as modeling software. Results The WAPPS-Hemo research network has been launched and is currently joined by 30 HTCs from across the world. We have gathered dense individual pharmacokinetic data on 878 subjects, including several replicates, on 21 different molecules from 17 different sources. We have collected sparse individual pharmacokinetic data on 289 subjects from the participating centers through the testing phase of the WAPPS-Hemo Web interface. We have developed prototypal population pharmacokinetics models for 11 molecules. The WAPPS-Hemo website (available at www.wapps-hemo.org, version 2.4), with core functionalities allowing hemophilia treaters to obtain individual pharmacokinetic estimates on sparse data points after 1 or more infusions of a factor concentrate, was launched for use within the research network in July 2015. Conclusions The WAPPS-Hemo project and research network aims to make it easier to perform individual pharmacokinetic assessments on a reduced number of plasma samples by adoption of a population pharmacokinetics approach. The project will also gather data to substantially enhance the current knowledge about factor concentrate pharmacokinetics and sources of its variability in target populations. Trial Registration ClinicalTrials.gov NCT02061072; https://clinicaltrials.gov/ct2/show/NCT02061072 (Archived by WebCite at http://www.webcitation.org/6mRK9bKP6) PMID:27977390

Future Freshwater Stress on Small Islands: Population, Aridity and Global Warming Targets

NASA Astrophysics Data System (ADS)

Karnauskas, K. B.; Schleussner, C. F.; Donnelly, J. P.; Anchukaitis, K. J.

2017-12-01

Small island developing states (SIDS) face multiple threats from anthropogenic climate change, including potential changes in freshwater resource availability. Future freshwater stress, including geographic and seasonal variability, has important implications for climate change adaptation scenarios for vulnerable human populations living on islands across the world ocean. Due to a mismatch in spatial scale between SIDS landforms and the horizontal resolution of global climate models (GCMs), SIDS are mostly unaccounted for in GCMs that are used to make future projections of global climate change and its regional impacts. Specific approaches are required to address this gap between broad-scale model projections and regional, policy-relevant outcomes. Here we apply a recently developed methodology to project future changes in aridity in combination with population projections associated with different shared socioeconomic pathways (SSPs) to evaluate overall changes in freshwater stress in SIDS at warming levels of 1.5°C and 2°C above pre-industrial levels. By accounting for evaporative demand a posteriori, we reveal a robust yet spatially variable tendency towards increasing aridity for 16 million people living on islands by mid-century. Although about half of the islands are projected to experience increased rainfall—predominantly in the deep tropics—projected changes in evaporation are more uniform, shifting the global distribution of changes in island freshwater balance towards greater aridity. In many cases, the magnitude of projected drying is comparable to the amplitude of the estimated observed interannual variability, with important consequences for extreme events. While we find that future population growth will dominate changes in projected freshwater stress especially towards the end of the century, projected changes in aridity are found to compound freshwater stress for the vast majority of SIDS. Particularly across the Caribbean region, a substantial fraction ( 25%) of the large overall freshwater stress projected under 2°C at 2030 can be avoided by limiting global warming to 1.5°C. Our findings add to a growing body of literature on the difference in climate impacts between 1.5°C and 2°C and underscore the need for regionally specific analysis.

An integral projection model with YY-males and application to evaluating grass carp control

USGS Publications Warehouse

Erickson, Richard A.; Eager, Eric A.; Brey, Marybeth; Hansen, Michael J.; Kocovsky, Patrick

2017-01-01

Invasive fish species disrupt ecosystems and cause economic damage. Several methods have been discussed to control populations of invasive fish including the release of YY-males. YY-males are fish that have 2 male chromosomes compared to a XY-male. When YY-males mate, they only produce male (XY) offspring. This decreases the female proportion of the population and can, in theory, eradicate local populations by biasing the sex-ratio. YY-males have been used as a population control tool for brook trout in montane streams and lakes in Idaho, USA. The YY-male control method has been discussed for grass carp in Lake Erie, North America. We developed and presented an integral projection model for grass carp to model the use of YY-males as a control method for populations in this lake. Using only the YY-male control method, we found that high levels of YY-males would need to be release annually to control the species. Specifically, these levels were the same order of magnitude as the baseline adult population (e.g., 1000 YY-males needed to be released annual for 20 years to control a baseline adult population of 2500 grass carp). These levels may not be reasonable or obtainable for fisheries managers given the impacts of YY-males on aquatic vegetation and other constraints of natural resource management.

How Will the San Francisco Bay-Delta Ecosystem Respond to Climate Change and Continued Population Growth?

NASA Astrophysics Data System (ADS)

Cloern, J.

2008-12-01

Programs to ensure sustainability of coastal ecosystems and the biological diversity they harbor require ecological forecasting to assess habitat transformations from the coupled effects of climate change and human population growth. A multidisciplinary modeling project (CASCaDE) was launched in 2007 to develop 21st-century visions of the Sacramento-San Joaquin Delta and San Francisco Bay under four scenarios of climate change and increasing demand for California's water resource. The process begins with downscaled projections of daily weather from GCM's and routes these to a watershed model that computes runoff and an operations model that computes inflows to the Bay-Delta. Hydrologic and climatic outputs, including sea level rise, drive models of tidal hydrodynamics-salinity-temperature in the Delta, sediment inputs and evolving geomorphology of San Francisco Bay. These projected habitat changes are being used to address priority questions asked by resource managers: How will changes in seasonal streamflow, salinity and water temperature, frequency of extreme weather and hydrologic events, and geomorphology influence the sustainability of native species that depend upon the Bay-Delta and the ecosystem services it provides?

Population Growth and Economic Development: Lessons from Selected Asian Countries. Policy Development Studies, Number 10.

ERIC Educational Resources Information Center

Mason, Andrew; And Others

The major findings of a research project on the relationship between population growth and economic development are summarized in this monograph. The study compares recent demographic and economic trends in Japan, Korea, Thailand, and Indonesia to worldwide experience as described by an econometric model of population and development. The study…

Projecting demographic responses to climate change: adult and juvenile survival respond differently to direct and indirect effects of weather in a passerine population

USGS Publications Warehouse

Dybala, Kristen E.; Eadie, John M.; Gardali, Thomas; Seavy, Nathaniel E.; Herzog, Mark P.

2013-01-01

Few studies have quantitatively projected changes in demography in response to climate change, yet doing so can provide important insights into the processes that may lead to population declines and changes in species distributions. Using a long-term mark-recapture data set, we examined the influence of multiple direct and indirect effects of weather on adult and juvenile survival for a population of Song Sparrows (Melospiza melodia) in California. We found evidence for a positive, direct effect of winter temperature on adult survival, and a positive, indirect effect of prior rainy season precipitation on juvenile survival, which was consistent with an effect of precipitation on food availability during the breeding season. We used these relationships, and climate projections of significantly warmer and slightly drier winter weather by the year 2100, to project a significant increase in mean adult survival (12-17%) and a slight decrease in mean juvenile survival (4-6%) under the B1 and A2 climate change scenarios. Together with results from previous studies on seasonal fecundity and postfledging survival in this population, we integrated these results in a population model and projected increases in the population growth rate under both climate change scenarios. Our results underscore the importance of considering multiple, direct, and indirect effects of weather throughout the annual cycle, as well as differences in the responses of each life stage to climate change. Projecting demographic responses to climate change can identify not only how populations will be affected by climate change but also indicate the demographic process(es) and specific mechanisms that may be responsible. This information can, in turn, inform climate change adaptation plans, help prioritize future research, and identify where limited conservation resources will be most effectively and efficiently spent.

Constructing an Urban Population Model for Medical Insurance Scheme Using Microsimulation Techniques

PubMed Central

Xiong, Linping; Zhang, Lulu; Tang, Weidong; Ma, Yuqin

2012-01-01

China launched a pilot project of medical insurance reform in 79 cities in 2007 to cover urban nonworking residents. An urban population model was created in this paper for China's medical insurance scheme using microsimulation model techniques. The model made it clear for the policy makers the population distributions of different groups of people, the potential urban residents entering the medical insurance scheme. The income trends of units of individuals and families were also obtained. These factors are essential in making the challenging policy decisions when considering to balance the long-term financial sustainability of the medical insurance scheme. PMID:22481973

Hospitality Occupational Skills Training Cooperative. Project HOST Final Report.

ERIC Educational Resources Information Center

Northwest Educational Cooperative, Des Plaines, IL.

Project HOST (Hospitality Occupational Skills Training) provided vocational training and employment opportunities in the hotel industry to disadvantaged adult minority populations in Chicago. It demonstrated a model for successful cooperation between the business sector and a public vocational education agency and developed and piloted a…

Women and Poverty in Saskatchewan.

ERIC Educational Resources Information Center

Whyte, Jayne Melville; Thompson, Loraine

A project explored female poverty in Saskatchewan, Canada, and its implications within the framework of Health Canada's Population Health Promotion Model. Data were collected through consultations with 59 women who had experienced poverty, interviews with administrators of agencies and projects that serve poor women, and a literature review.…

Tripartite Governance: Enabling Successful Implementations with Vulnerable Populations.

PubMed

Kennedy, Margaret Ann

2016-01-01

Vulnerable populations are often at a distinct disadvantage when it comes to the implementation of health information systems in an equitable, appropriate, and timely manner. The disadvantages experienced by vulnerable populations are innumerable and include lack of representation, lack of appropriate levels of funding, lack of resources and capacity, and lack of representation. Increasingly, models of representation for complex implementations involve a tripartite project governance model. This tripartite partnership distributes accountability across all partners, and ensures that vulnerable populations have an equitable contribution to the direction of implementation according to their needs. This article shares lessons learned and best practices from complex tripartite partnerships supporting implementations with vulnerable populations in Canada.

A supply model for nurse workforce projection in Malaysia.

PubMed

Abas, Zuraida Abal; Ramli, Mohamad Raziff; Desa, Mohamad Ishak; Saleh, Nordin; Hanafiah, Ainul Nadziha; Aziz, Nuraini; Abidin, Zaheera Zainal; Shibghatullah, Abdul Samad; Rahman, Ahmad Fadzli Nizam Abdul; Musa, Haslinda

2017-08-18

The paper aims to provide an insight into the significance of having a simulation model to forecast the supply of registered nurses for health workforce planning policy using System Dynamics. A model is highly in demand to predict the workforce demand for nurses in the future, which it supports for complete development of a needs-based nurse workforce projection using Malaysia as a case study. The supply model consists of three sub-models to forecast the number of registered nurses for the next 15 years: training model, population model and Full Time Equivalent (FTE) model. In fact, the training model is for predicting the number of newly registered nurses after training is completed. Furthermore, the population model is for indicating the number of registered nurses in the nation and the FTE model is useful for counting the number of registered nurses with direct patient care. Each model is described in detail with the logical connection and mathematical governing equation for accurate forecasting. The supply model is validated using error analysis approach in terms of the root mean square percent error and the Theil inequality statistics, which is mportant for evaluating the simulation results. Moreover, the output of simulation results provides a useful insight for policy makers as a what-if analysis is conducted. Some recommendations are proposed in order to deal with the nursing deficit. It must be noted that the results from the simulation model will be used for the next stage of the Needs-Based Nurse Workforce projection project. The impact of this study is that it provides the ability for greater planning and policy making with better predictions.

Potential distribution of dengue fever under scenarios of climate change and economic development.

PubMed

Aström, Christofer; Rocklöv, Joacim; Hales, Simon; Béguin, Andreas; Louis, Valerie; Sauerborn, Rainer

2012-12-01

Dengue fever is the most important viral vector-borne disease with ~50 million cases per year globally. Previous estimates of the potential effect of global climate change on the distribution of vector-borne disease have not incorporated the effect of socioeconomic factors, which may have biased the results. We describe an empirical model of the current geographic distribution of dengue, based on the independent effects of climate and gross domestic product per capita (GDPpc, a proxy for socioeconomic development). We use the model, along with scenario-based projections of future climate, economic development, and population, to estimate populations at risk of dengue in the year 2050. We find that both climate and GDPpc influence the distribution of dengue. If the global climate changes as projected but GDPpc remained constant, the population at risk of dengue is estimated to increase by about 0.28 billion in 2050. However, if both climate and GDPpc change as projected, we estimate a decrease of 0.12 billion in the population at risk of dengue in 2050. Empirically, the geographic distribution of dengue is strongly dependent on both climatic and socioeconomic variables. Under a scenario of constant GDPpc, global climate change results in a modest but important increase in the global population at risk of dengue. Under scenarios of high GDPpc, this adverse effect of climate change is counteracted by the beneficial effect of socioeconomic development.

Socio-Cultural Case Studies for Population Education in Morocco, Peru, Rwanda and the United Republic of Tanzania. Co-ordinated Action Programme for the Advancement of Population Education (CAPAPE).

ERIC Educational Resources Information Center

United Nations Educational, Scientific, and Cultural Organization, Paris (France). Population Education Section.

Developed to serve as a guide, this document contains four case studies which demonstrate the application of a conceptual and methodological reference model which promotes the use of socio-cultural research in national population education projects. Information obtained from these kinds of studies can be used in developing population education…

Conservation status of polar bears (Ursus maritimus) in relation to projected sea-ice declines

NASA Astrophysics Data System (ADS)

Laidre, K. L.; Regehr, E. V.; Akcakaya, H. R.; Amstrup, S. C.; Atwood, T.; Lunn, N.; Obbard, M.; Stern, H. L., III; Thiemann, G.; Wiig, O.

2016-12-01

Loss of Arctic sea ice due to climate change is the most serious threat to polar bears (Ursus maritimus) throughout their circumpolar range. We performed a data-based sensitivity analysis with respect to this threat by evaluating the potential response of the global polar bear population to projected sea-ice conditions. We conducted 1) an assessment of generation length for polar bears, 2) developed of a standardized sea-ice metric representing important habitat characteristics for the species; and 3) performed population projections over three generations, using computer simulation and statistical models representing alternative relationships between sea ice and polar bear abundance. Using three separate approaches, the median percent change in mean global population size for polar bears between 2015 and 2050 ranged from -4% (95% CI = -62%, 50%) to -43% (95% CI = -76%, -20%). Results highlight the potential for large reductions in the global population if sea-ice loss continues. They also highlight the large amount of uncertainty in statistical projections of polar bear abundance and the sensitivity of projections to plausible alternative assumptions. The median probability of a reduction in the mean global population size of polar bears greater than 30% over three generations was approximately 0.71 (range 0.20-0.95. The median probability of a reduction greater than 50% was approximately 0.07 (range 0-0.35), and the probability of a reduction greater than 80% was negligible.

The implications of regional and national demographic projections for future GMS costs in Ireland through to 2026.

PubMed

Conway, Aisling; Kenneally, Martin; Woods, Noel; Thummel, Andreas; Ryan, Marie

2014-10-21

As the health services in Ireland have become more resource-constrained, pressure has increased to reduce public spending on community drug schemes such as General Medical Services (GMS) drug prescribing and to understand current and future trends in prescribing. The GMS scheme covers approximately 37% of the Irish population in 2011 and entitles them, inter alia, to free prescription drugs and appliances. This paper projects the effects of future changes in population, coverage, claims rates and average claims cost on GMS costs in Ireland. Data on GMS coverage, claims rates and average cost per claim are drawn from the Primary Care Reimbursement Service (PCRS) and combined with Central Statistics Office (CSO) (Regional and National Population Projections through to 2026). A Monte Carlo Model is used to simulate the effects of demographic change (by region, age, gender, coverage, claims rates and average claims cost) will have on GMS prescribing costs in 2016, 2021 and 2026 under different scenarios. The Population of Ireland is projected to grow by 32% between 2007 and 2026 and by 96% for the over 70s. The Eastern region is estimated to grow by 3% over the lifetime of the projections at the expense of most other regions. The Monte Carlo simulations project that females will be a bigger driver of GMS costs than males. Midlands region will be the most expensive of the eight old health board regions. Those aged 70 and over and children under 11 will be significant drivers of GMS costs with the impending demographic changes. Overall GMS medicines costs are projected to rise to €1.9bn by 2026. Ireland's population will experience rapid growth over the next decade. Population growth coupled with an aging population will result in an increase in coverage rates, thus the projected increase in overall prescribing costs. Our projections and simulations map the likely evolution of GMS cost, given existing policies and demographic trends. These costs can be contained by government policy initiatives.

The Addicted-Self Model of addictive behavior cessation: does it predict recovery for gender, ethnic, age and drug preference populations?

PubMed

Fiorentine, Robert; Hillhouse, Maureen P

2004-01-01

Although previous research provided empirical support for the main assumptions of the Addicted-Self (A-S) Model of recovery, it is not known whether the model predicts recovery for various gender, ethnic, age, and drug preference populations. It may be that the model predicts recovery only for some groups of addicts and should not be viewed as a general theory of the recovery process. Addressing this concern using data from the Los Angeles Target Cities Drug Treatment Enhancement Project, it was determined that only trivial population differences exist in the primary variables associated with the A-S Model. The A-S Model predicts abstinence with about the same degree of accuracy and parsimony for all populations. The findings indicate that the A-S Model is a general theory of drug and alcohol addictive behavior cessation.

Use of a GIS-based model of habitat cores and landscape corridors for the Virginia Department of Transportation's project planning and environmental scoping.

DOT National Transportation Integrated Search

2006-01-01

As important habitats are being lost to human development, transportation agencies are facing increased expectations that their road projects avoid or minimize further habitat destruction and adverse effects on wildlife populations. Wildlife linkage ...

78 FR 27957 - Fisheries of the South Atlantic, Southeast Data, Assessment, and Review (SEDAR); Public Meetings

Federal Register 2010, 2011, 2012, 2013, 2014

2013-05-13

..., describes the fisheries, evaluates the status of the stock, estimates biological benchmarks, projects future.... Participants will evaluate and recommend datasets appropriate for assessment analysis, employ assessment models to evaluate stock status, estimate population benchmarks and management criteria, and project future...

Projected poleward shift of king penguins' (Aptenodytes patagonicus) foraging range at the Crozet Islands, southern Indian Ocean.

PubMed

Péron, Clara; Weimerskirch, Henri; Bost, Charles-André

2012-07-07

Seabird populations of the Southern Ocean have been responding to climate change for the last three decades and demographic models suggest that projected warming will cause dramatic population changes over the next century. Shift in species distribution is likely to be one of the major possible adaptations to changing environmental conditions. Habitat models based on a unique long-term tracking dataset of king penguin (Aptenodytes patagonicus) breeding on the Crozet Islands (southern Indian Ocean) revealed that despite a significant influence of primary productivity and mesoscale activity, sea surface temperature consistently drove penguins' foraging distribution. According to climate models of the Intergovernmental Panel on Climate Change (IPCC), the projected warming of surface waters would lead to a gradual southward shift of the more profitable foraging zones, ranging from 25 km per decade for the B1 IPCC scenario to 40 km per decade for the A1B and A2 scenarios. As a consequence, distances travelled by incubating and brooding birds to reach optimal foraging zones associated with the polar front would double by 2100. Such a shift is far beyond the usual foraging range of king penguins breeding and would negatively affect the Crozet population on the long term, unless penguins develop alternative foraging strategies.

Projected poleward shift of king penguins' (Aptenodytes patagonicus) foraging range at the Crozet Islands, southern Indian Ocean

PubMed Central

Péron, Clara; Weimerskirch, Henri; Bost, Charles-André

2012-01-01

Seabird populations of the Southern Ocean have been responding to climate change for the last three decades and demographic models suggest that projected warming will cause dramatic population changes over the next century. Shift in species distribution is likely to be one of the major possible adaptations to changing environmental conditions. Habitat models based on a unique long-term tracking dataset of king penguin (Aptenodytes patagonicus) breeding on the Crozet Islands (southern Indian Ocean) revealed that despite a significant influence of primary productivity and mesoscale activity, sea surface temperature consistently drove penguins' foraging distribution. According to climate models of the Intergovernmental Panel on Climate Change (IPCC), the projected warming of surface waters would lead to a gradual southward shift of the more profitable foraging zones, ranging from 25 km per decade for the B1 IPCC scenario to 40 km per decade for the A1B and A2 scenarios. As a consequence, distances travelled by incubating and brooding birds to reach optimal foraging zones associated with the polar front would double by 2100. Such a shift is far beyond the usual foraging range of king penguins breeding and would negatively affect the Crozet population on the long term, unless penguins develop alternative foraging strategies. PMID:22378808

FITPOP, a heuristic simulation model of population dynamics and genetics with special reference to fisheries

USGS Publications Warehouse

McKenna, James E.

2000-01-01

Although, perceiving genetic differences and their effects on fish population dynamics is difficult, simulation models offer a means to explore and illustrate these effects. I partitioned the intrinsic rate of increase parameter of a simple logistic-competition model into three components, allowing specification of effects of relative differences in fitness and mortality, as well as finite rate of increase. This model was placed into an interactive, stochastic environment to allow easy manipulation of model parameters (FITPOP). Simulation results illustrated the effects of subtle differences in genetic and population parameters on total population size, overall fitness, and sensitivity of the system to variability. Several consequences of mixing genetically distinct populations were illustrated. For example, behaviors such as depression of population size after initial introgression and extirpation of native stocks due to continuous stocking of genetically inferior fish were reproduced. It also was shown that carrying capacity relative to the amount of stocking had an important influence on population dynamics. Uncertainty associated with parameter estimates reduced confidence in model projections. The FITPOP model provided a simple tool to explore population dynamics, which may assist in formulating management strategies and identifying research needs.

Updates to the Demographic and Spatial Allocation Models to ...

EPA Pesticide Factsheets

EPA announced the availability of the draft report, Updates to the Demographic and Spatial Allocation Models to Produce Integrated Climate and Land Use Scenarios (ICLUS) for a 30-day public comment period. The ICLUS version 2 (v2) modeling tool furthered land change modeling by providing nationwide housing development scenarios up to 2100. ICLUS V2 includes updated population and land use data sets and addressing limitations identified in ICLUS v1 in both the migration and spatial allocation models. The companion user guide describes the development of ICLUS v2 and the updates that were made to the original data sets and the demographic and spatial allocation models. [2017 UPDATE] Get the latest version of ICLUS and stay up-to-date by signing up to the ICLUS mailing list. The GIS tool enables users to run SERGoM with the population projections developed for the ICLUS project and allows users to modify the spatial allocation housing density across the landscape.

Using demography and movement behavior to predict range expansion of the southern sea otter.

USGS Publications Warehouse

Tinker, M.T.; Doak, D.F.; Estes, J.A.

2008-01-01

In addition to forecasting population growth, basic demographic data combined with movement data provide a means for predicting rates of range expansion. Quantitative models of range expansion have rarely been applied to large vertebrates, although such tools could be useful for restoration and management of many threatened but recovering populations. Using the southern sea otter (Enhydra lutris nereis) as a case study, we utilized integro-difference equations in combination with a stage-structured projection matrix that incorporated spatial variation in dispersal and demography to make forecasts of population recovery and range recolonization. In addition to these basic predictions, we emphasize how to make these modeling predictions useful in a management context through the inclusion of parameter uncertainty and sensitivity analysis. Our models resulted in hind-cast (1989–2003) predictions of net population growth and range expansion that closely matched observed patterns. We next made projections of future range expansion and population growth, incorporating uncertainty in all model parameters, and explored the sensitivity of model predictions to variation in spatially explicit survival and dispersal rates. The predicted rate of southward range expansion (median = 5.2 km/yr) was sensitive to both dispersal and survival rates; elasticity analysis indicated that changes in adult survival would have the greatest potential effect on the rate of range expansion, while perturbation analysis showed that variation in subadult dispersal contributed most to variance in model predictions. Variation in survival and dispersal of females at the south end of the range contributed most of the variance in predicted southward range expansion. Our approach provides guidance for the acquisition of further data and a means of forecasting the consequence of specific management actions. Similar methods could aid in the management of other recovering populations.

Comparing models of Red Knot population dynamics

USGS Publications Warehouse

McGowan, Conor P.

2015-01-01

Predictive population modeling contributes to our basic scientific understanding of population dynamics, but can also inform management decisions by evaluating alternative actions in virtual environments. Quantitative models mathematically reflect scientific hypotheses about how a system functions. In Delaware Bay, mid-Atlantic Coast, USA, to more effectively manage horseshoe crab (Limulus polyphemus) harvests and protect Red Knot (Calidris canutus rufa) populations, models are used to compare harvest actions and predict the impacts on crab and knot populations. Management has been chiefly driven by the core hypothesis that horseshoe crab egg abundance governs the survival and reproduction of migrating Red Knots that stopover in the Bay during spring migration. However, recently, hypotheses proposing that knot dynamics are governed by cyclical lemming dynamics garnered some support in data analyses. In this paper, I present alternative models of Red Knot population dynamics to reflect alternative hypotheses. Using 2 models with different lemming population cycle lengths and 2 models with different horseshoe crab effects, I project the knot population into the future under environmental stochasticity and parametric uncertainty with each model. I then compare each model's predictions to 10 yr of population monitoring from Delaware Bay. Using Bayes' theorem and model weight updating, models can accrue weight or support for one or another hypothesis of population dynamics. With 4 models of Red Knot population dynamics and only 10 yr of data, no hypothesis clearly predicted population count data better than another. The collapsed lemming cycle model performed best, accruing ~35% of the model weight, followed closely by the horseshoe crab egg abundance model, which accrued ~30% of the weight. The models that predicted no decline or stable populations (i.e. the 4-yr lemming cycle model and the weak horseshoe crab effect model) were the most weakly supported.

Model of Numerical Spatial Classification for Sustainable Agriculture in Badung Regency and Denpasar City, Indonesia

NASA Astrophysics Data System (ADS)

Trigunasih, N. M.; Lanya, I.; Subadiyasa, N. N.; Hutauruk, J.

2018-02-01

Increasing number and activity of the population to meet the needs of their lives greatly affect the utilization of land resources. Land needs for activities of the population continue to grow, while the availability of land is limited. Therefore, there will be changes in land use. As a result, the problems faced by land degradation and conversion of agricultural land become non-agricultural. The objectives of this research are: (1) to determine parameter of spatial numerical classification of sustainable food agriculture in Badung Regency and Denpasar City (2) to know the projection of food balance in Badung Regency and Denpasar City in 2020, 2030, 2040, and 2050 (3) to specify of function of spatial numerical classification in the making of zonation model of sustainable agricultural land area in Badung regency and Denpasar city (4) to determine the appropriate model of the area to protect sustainable agricultural land in spatial and time scale in Badung and Denpasar regencies. The method used in this research was quantitative method include: survey, soil analysis, spatial data development, geoprocessing analysis (spatial analysis of overlay and proximity analysis), interpolation of raster digital elevation model data, and visualization (cartography). Qualitative methods consisted of literature studies, and interviews. The parameters observed for a total of 11 parameters Badung regency and Denpasar as much as 9 parameters. Numerical classification parameter analysis results used the standard deviation and the mean of the population data and projections relationship rice field in the food balance sheet by modelling. The result of the research showed that, the number of different numerical classification parameters in rural areas (Badung) and urban areas (Denpasar), in urban areas the number of parameters is less than the rural areas. The based on numerical classification weighting and scores generate population distribution parameter analysis results of a standard deviation and average value. Numerical classification produced 5 models, which was divided into three zones are sustainable neighbourhood, buffer and converted in Denpasar and Badung. The results of Population curve parameter analysis in Denpasar showed normal curve, in contrast to the Badung regency showed abnormal curve, therefore Denpasar modeling carried out throughout the region, while in the Badung regency modeling done in each district. Relationship modelling and projections lands role in food balance in Badung views of sustainable land area whereas in Denpasar seen from any connection to the green open spaces in the spatial plan Denpasar 2011-2031. Modelling in Badung (rural) is different in Denpasar (urban), as well as population curve parameter analysis results in Badung showed abnormal curve while in Denpasar showed normal curve. Relationship modelling and projections lands role in food balance in the Badung regency sustainable in terms of land area, while in Denpasar in terms of linkages with urban green space in Denpasar City’s regional landuse plan of 2011-2031.

Time to act: crossing borders in global AIDS prevention.

PubMed

Convisser, J; Thuermer, K

1993-01-01

After 9 months of market research and collaboration among local health officials, businesses, politicians, and teenagers, Population Services International (PSI) launched Project ACTION in Portland, Oregon on December 1, 1992. It is the first PSI project in the United States concerned with prevention of human immunodeficiency virus (HIV) and acquired immunodeficiency syndrome (AIDS) in American youth. PSI has conducted 23 projects worldwide over the last 20 years that were based on social marketing (the utilization of commercial marketing techniques to promote healthy behavior). The objective of the project is promotion of safe sex practices, especially the use of condoms, among sexually active youth, aged 12-21. The Mass Media and Condom Social Marketing project of PSI in Zaire was used as a model for Project ACTION. Techniques used include mass marketing campaigns, point of purchase promotion, improvement of access to key products among target populations, and adjustment of purchase price to create a market. The target populations include adolescents who use drugs, are involved with the juvenile justice system, are pregnant, have a problem home environment, are homeless or live on the street, are chronically absent from school, or have a history of sexually transmitted disease.

Modeling the effects of land use and climate change on riverine smallmouth bass

USGS Publications Warehouse

Peterson, J.T.; Kwak, T.J.

1999-01-01

Anthropogenic changes in temperature and stream flow, associated with watershed land use and climate change, are critical influences on the distribution and abundance of riverine fishes. To project the effects of changing land use and climate, we modeled a smallmouth bass (Micropterus dolomieu) population in a midwestern USA, large river- floodplain ecosystem under historical (1915-1925), present (1977-1990), and future (2060, influenced by climate change) temperature and flow regimes. The age-structured model included parameters for temperature and river discharge during critical seasonal periods, fish population dynamics, and fishing harvest. Model relationships were developed from empirical field data collected over a 13-yr period. Sensitivity analyses indicated that discharge during the spawning/rearing period had a greater effect on adult density and fishing yield than did spawning/rearing temperature or winter discharge. Simulations for 100 years projected a 139% greater mean fish density under a historical flow regime (64.9 fish/ha) than that estimated for the present (27.1 fish/ha) with a sustainable fishing harvest under both flow regimes. Simulations under future climate-change-induced temperature and flow regimes with present land use projected a 69% decrease in mean fish density (8.5 fish/ha) from present and an unstable population that went extinct during 56% of the simulations. However, when simulated under a future climate-altered temperature and flow regime with historical land use, the population increased by 66% (45.0 fish/ha) from present and sustained a harvest. Our findings suggest that land-use changes may be a greater detriment to riverine fishes than projected climate change and that the combined effects of both factors may lead to local species extinction. However, the negative effects of increased temperature and precipitation associated with future global warming could be mitigated by river channel, floodplain, and watershed restoration.

Western Pacific emergent constraint lowers projected increase in Indian summer monsoon rainfall

NASA Astrophysics Data System (ADS)

Li, Gen; Xie, Shang-Ping; He, Chao; Chen, Zesheng

2017-10-01

The agrarian-based socioeconomic livelihood of densely populated South Asian countries is vulnerable to modest changes in Indian summer monsoon (ISM) rainfall. How the ISM rainfall will evolve is a question of broad scientific and socioeconomic importance. In response to increased greenhouse gas (GHG) forcing, climate models commonly project an increase in ISM rainfall. This wetter ISM projection, however, does not consider large model errors in both the mean state and ocean warming pattern. Here we identify a relationship between biases in simulated present climate and future ISM projections in a multi-model ensemble: models with excessive present-day precipitation over the tropical western Pacific tend to project a larger increase in ISM rainfall under GHG forcing because of too strong a negative cloud-radiation feedback on sea surface temperature. The excessive negative feedback suppresses the local ocean surface warming, strengthening ISM rainfall projections via atmospheric circulation. We calibrate the ISM rainfall projections using this `present-future relationship’ and observed western Pacific precipitation. The correction reduces by about 50% of the projected rainfall increase over the broad ISM region. Our study identifies an improved simulation of western Pacific convection as a priority for reliable ISM projections.

UNFINISHED JOURNEY Project. Quarterly report, September 1994--December 1994

DOE Office of Scientific and Technical Information (OSTI.GOV)

NONE

1998-02-01

In September, 1994, the U.S. Department of Energy (Nevada Operations Office) made a $199,708 grant (through the Mathematics, Science, and Technology Education Program), to the UNFINISHED JOURNEY Project. The Project began in April, 1994, to develop and implement an innovative model of student outreach by San Jose State University (SJSU) to underserved, underrepresented student populations of the East Side Union High School District (ESUHSD). The Project was formed by a consortium involving SJSU, ESUHSD, some 20 private sector organizations (foundations/corporations), numerous local community/professional organizations, and approximately 100 private funders. This proposal to the U.S. Department of Energy was to havemore » the Department join this unique partnership to focus University outreach to underserved student populations to pursue careers in mathematics, science, and technology.« less

Oceanography and life history predict contrasting genetic population structure in two Antarctic fish species.

PubMed

Young, Emma F; Belchier, Mark; Hauser, Lorenz; Horsburgh, Gavin J; Meredith, Michael P; Murphy, Eugene J; Pascoal, Sonia; Rock, Jennifer; Tysklind, Niklas; Carvalho, Gary R

2015-06-01

Understanding the key drivers of population connectivity in the marine environment is essential for the effective management of natural resources. Although several different approaches to evaluating connectivity have been used, they are rarely integrated quantitatively. Here, we use a 'seascape genetics' approach, by combining oceanographic modelling and microsatellite analyses, to understand the dominant influences on the population genetic structure of two Antarctic fishes with contrasting life histories, Champsocephalus gunnari and Notothenia rossii. The close accord between the model projections and empirical genetic structure demonstrated that passive dispersal during the planktonic early life stages is the dominant influence on patterns and extent of genetic structuring in both species. The shorter planktonic phase of C. gunnari restricts direct transport of larvae between distant populations, leading to stronger regional differentiation. By contrast, geographic distance did not affect differentiation in N. rossii, whose longer larval period promotes long-distance dispersal. Interannual variability in oceanographic flows strongly influenced the projected genetic structure, suggesting that shifts in circulation patterns due to climate change are likely to impact future genetic connectivity and opportunities for local adaptation, resilience and recovery from perturbations. Further development of realistic climate models is required to fully assess such potential impacts.

The E-MOSAICS project: simulating the formation and co-evolution of galaxies and their star cluster populations

NASA Astrophysics Data System (ADS)

Pfeffer, Joel; Kruijssen, J. M. Diederik; Crain, Robert A.; Bastian, Nate

2018-04-01

We introduce the MOdelling Star cluster population Assembly In Cosmological Simulations within EAGLE (E-MOSAICS) project. E-MOSAICS incorporates models describing the formation, evolution, and disruption of star clusters into the EAGLE galaxy formation simulations, enabling the examination of the co-evolution of star clusters and their host galaxies in a fully cosmological context. A fraction of the star formation rate of dense gas is assumed to yield a cluster population; this fraction and the population's initial properties are governed by the physical properties of the natal gas. The subsequent evolution and disruption of the entire cluster population are followed accounting for two-body relaxation, stellar evolution, and gravitational shocks induced by the local tidal field. This introductory paper presents a detailed description of the model and initial results from a suite of 10 simulations of ˜L⋆ galaxies with disc-like morphologies at z = 0. The simulations broadly reproduce key observed characteristics of young star clusters and globular clusters (GCs), without invoking separate formation mechanisms for each population. The simulated GCs are the surviving population of massive clusters formed at early epochs (z ≳ 1-2), when the characteristic pressures and surface densities of star-forming gas were significantly higher than observed in local galaxies. We examine the influence of the star formation and assembly histories of galaxies on their cluster populations, finding that (at similar present-day mass) earlier-forming galaxies foster a more massive and disruption-resilient cluster population, while galaxies with late mergers are capable of forming massive clusters even at late cosmic epochs. We find that the phenomenological treatment of interstellar gas in EAGLE precludes the accurate modelling of cluster disruption in low-density environments, but infer that simulations incorporating an explicitly modelled cold interstellar gas phase will overcome this shortcoming.

Incorporating population-level variation in thermal performance into predictions of geographic range shifts.

PubMed

Angert, Amy L; Sheth, Seema N; Paul, John R

2011-11-01

Determining how species' geographic ranges are governed by current climates and how they will respond to rapid climatic change poses a major biological challenge. Geographic ranges are often spatially fragmented and composed of genetically differentiated populations that are locally adapted to different thermal regimes. Tradeoffs between different aspects of thermal performance, such as between tolerance to high temperature and tolerance to low temperature or between maximal performance and breadth of performance, suggest that the performance of a given population will be a subset of that of the species. Therefore, species-level projections of distribution might overestimate the species' ability to persist at any given location. However, current approaches to modeling distributions often do not consider variation among populations. Here, we estimated genetically-based differences in thermal performance curves for growth among 12 populations of the scarlet monkeyflower, Mimulus cardinalis, a perennial herb of western North America. We inferred the maximum relative growth rate (RGR(max)), temperature optimum (T(opt)), and temperature breadth (T(breadth)) for each population. We used these data to test for tradeoffs in thermal performance, generate mechanistic population-level projections of distribution under current and future climates, and examine how variation in aspects of thermal performance influences forecasts of range shifts. Populations differed significantly in RGR(max) and had variable, but overlapping, estimates of T(opt) and T(breadth). T(opt) declined with latitude and increased with temperature of origin, consistent with tradeoffs between performances at low temperatures versus those at high temperatures. Further, T(breadth) was negatively related to RGR(max), as expected for a specialist-generalist tradeoff. Parameters of the thermal performance curve influenced properties of projected distributions. For both current and future climates, T(opt) was negatively related to latitudinal position, while T(breadth) was positively related to projected range size. The magnitude and direction of range shifts also varied with T(opt) and T(breadth), but sometimes in unexpected ways. For example, the fraction of habitat remaining suitable increased with T(opt) but decreased with T(breadth). Northern limits of all populations were projected to shift north, but the magnitude of shift decreased with T(opt) and increased with T(breadth). Median latitude was projected to shift north for populations with high T(breadth) and low T(opt), but south for populations with low T(breadth) and high T(opt). Distributions inferred by integrating population-level projections did not differ from a species-level projection that ignored variation among populations. However, the species-level approach masked the potential array of divergent responses by populations that might lead to genotypic sorting within the species' range. Thermal performance tradeoffs among populations within the species' range had important, but sometimes counterintuitive, effects on projected responses to climatic change. © The Author 2011. Published by Oxford University Press on behalf of the Society for Integrative and Comparative Biology. All rights reserved.

Predicting the effects of climate change on population connectivity and genetic diversity of an imperiled freshwater mussel, Cumberlandia monodonta (Bivalvia: Margaritiferidae), in riverine systems.

PubMed

Inoue, Kentaro; Berg, David J

2017-01-01

In the face of global climate change, organisms may respond to temperature increases by shifting their ranges poleward or to higher altitudes. However, the direction of range shifts in riverine systems is less clear. Because rivers are dendritic networks, there is only one dispersal route from any given location to another. Thus, range shifts are only possible if branches are connected by suitable habitat, and stream-dwelling organisms can disperse through these branches. We used Cumberlandia monodonta (Bivalvia: Unionoida: Margaritiferidae) as a model species to investigate the effects of climate change on population connectivity because a majority of contemporary populations are panmictic. We combined ecological niche models (ENMs) with population genetic simulations to investigate the effects of climate change on population connectivity and genetic diversity of C. monodonta. The ENMs were constructed using bioclimatic and landscape data to project shifts in suitable habitat under future climate scenarios. We then used forward-time simulations to project potential changes in genetic diversity and population connectivity based on these range shifts. ENM results under current conditions indicated long stretches of highly suitable habitat in rivers where C. monodonta persists; populations in the upper Mississippi River remain connected by suitable habitat that does not impede gene flow. Future climate scenarios projected northward and headwater-ward range contraction and drastic declines in habitat suitability for most extant populations throughout the Mississippi River Basin. Simulations indicated that climate change would greatly reduce genetic diversity and connectivity across populations. Results suggest that a single, large population of C. monodonta will become further fragmented into smaller populations, each of which will be isolated and begin to differentiate genetically. Because C. monodonta is a widely distributed species and purely aquatic, our results suggest that persistence and connectivity of stream-dwelling organisms will be significantly altered in response to future climate change. © 2016 John Wiley & Sons Ltd.

Vulnerability Reduction Needed to Maintain Current Burdens of Heat-Related Mortality in a Changing Climate-Magnitude and Determinants.

PubMed

Åström, Christofer; Åström, Daniel Oudin; Andersson, Camilla; Ebi, Kristie L; Forsberg, Bertil

2017-07-07

The health burden from heatwaves is expected to increase with rising global mean temperatures and more extreme heat events over the coming decades. Health-related effects from extreme heat are more common in elderly populations. The population of Europe is rapidly aging, which will increase the health effects of future temperatures. In this study, we estimate the magnitude of adaptation needed to lower vulnerability to heat in order to prevent an increase in heat-related deaths in the 2050s; this is the Adaptive Risk Reduction (ARR) needed. Temperature projections under Representative Concentration Pathway (RCP) 4.5 and RCP 8.5 from 18 climate models were coupled with gridded population data and exposure-response relationships from a European multi-city study on heat-related mortality. In the 2050s, the ARR for the general population is 53.5%, based on temperature projections under RCP 4.5. For the population above 65 years in Southern Europe, the ARR is projected to be 45.9% in a future with an unchanged climate and 74.7% with climate change under RCP 4.5. The ARRs were higher under RCP 8.5. Whichever emission scenario is followed or population projection assumed, Europe will need to adapt to a great degree to maintain heat-related mortality at present levels, which are themselves unacceptably high, posing an even greater challenge.

Vulnerability Reduction Needed to Maintain Current Burdens of Heat-Related Mortality in a Changing Climate—Magnitude and Determinants

PubMed Central

Åström, Christofer; Oudin Åström, Daniel; Andersson, Camilla; L. Ebi, Kristie; Forsberg, Bertil

2017-01-01

The health burden from heatwaves is expected to increase with rising global mean temperatures and more extreme heat events over the coming decades. Health-related effects from extreme heat are more common in elderly populations. The population of Europe is rapidly aging, which will increase the health effects of future temperatures. In this study, we estimate the magnitude of adaptation needed to lower vulnerability to heat in order to prevent an increase in heat-related deaths in the 2050s; this is the Adaptive Risk Reduction (ARR) needed. Temperature projections under Representative Concentration Pathway (RCP) 4.5 and RCP 8.5 from 18 climate models were coupled with gridded population data and exposure-response relationships from a European multi-city study on heat-related mortality. In the 2050s, the ARR for the general population is 53.5%, based on temperature projections under RCP 4.5. For the population above 65 years in Southern Europe, the ARR is projected to be 45.9% in a future with an unchanged climate and 74.7% with climate change under RCP 4.5. The ARRs were higher under RCP 8.5. Whichever emission scenario is followed or population projection assumed, Europe will need to adapt to a great degree to maintain heat-related mortality at present levels, which are themselves unacceptably high, posing an even greater challenge. PMID:28686197

[Consequences of increasing and ageing population of Basse-Normandie on gynecology and obstetrics activity].

PubMed

Mandon, M; Macé, J-M; Dreyfus, M; Berger, L

2015-11-01

In Basse-Normandie, the population over 65 years old will expend more rapidly between 2007 and 2042 (+11.6%) than the rest of the French population (+9.2%). The same population of Basse-Normandie will get old in the 15 years to come. The impact of these demographic changes over the activity in the gynecology-obstetrics field is not clearly identified. Although we cannot predict the technical and scientific developments in the next 15 years, we are presenting a model allowing to hypothesize about changes of gynecology and obstetrics according to population's aging. We have established a projection model for the realizable surgical acts in obstetrics and gynecology in accordance with the aging of the population in Basse-Normandie. The study was realized based on the acts concerning the cesarean sections (C-section), tubal sterilization, hysteroscopy and hysterectomy as well as ovarectomy and breast surgery. For each activity branch, the codes of the Classification commune des actes médicaux (CCAM) were selected and then removed from the Programme médicalisé des systèmes d'information (PMSI) database. We have used and adapted the Omphale model of the National Statistics and Economical Studies Institute and we have applied it for the period of 2009-2025. Our projection model has permeated to show a 5.5% regression of the C-section acts, a 2% incretion of the hysterectomies and hysteroscopies, 7.7% of ovarectomies as well as a 9.8% augmentation of the breast surgeries. However, we predict a 11.8% diminution of the sterilizations by tubal implants. Globally, the activity in obstetrics and gynecology will remain constant with an insignificant augmentation of 46 acts (0.01%). In Basse-Normandie, the surgical activity in gynecology-obstetrics will moderately increase in the next 15 years. This constant activity signifies that there is no need to form more residents than the number of practitioner to retire. The interest of this model is that it is applicable at a national level and it permits to confront the demographic data and the projections of different activities. Copyright © 2014 Elsevier Masson SAS. All rights reserved.

Climate-driven vital rates do not always mean climate-driven population.

PubMed

Tavecchia, Giacomo; Tenan, Simone; Pradel, Roger; Igual, José-Manuel; Genovart, Meritxell; Oro, Daniel

2016-12-01

Current climatic changes have increased the need to forecast population responses to climate variability. A common approach to address this question is through models that project current population state using the functional relationship between demographic rates and climatic variables. We argue that this approach can lead to erroneous conclusions when interpopulation dispersal is not considered. We found that immigration can release the population from climate-driven trajectories even when local vital rates are climate dependent. We illustrated this using individual-based data on a trans-equatorial migratory seabird, the Scopoli's shearwater Calonectris diomedea, in which the variation of vital rates has been associated with large-scale climatic indices. We compared the population annual growth rate λ i , estimated using local climate-driven parameters with ρ i , a population growth rate directly estimated from individual information and that accounts for immigration. While λ i varied as a function of climatic variables, reflecting the climate-dependent parameters, ρ i did not, indicating that dispersal decouples the relationship between population growth and climate variables from that between climatic variables and vital rates. Our results suggest caution when assessing demographic effects of climatic variability especially in open populations for very mobile organisms such as fish, marine mammals, bats, or birds. When a population model cannot be validated or it is not detailed enough, ignoring immigration might lead to misleading climate-driven projections. © 2016 John Wiley & Sons Ltd.

Multi-model assessment of water scarcity under climate change

NASA Astrophysics Data System (ADS)

Schewe, J.; Heinke, J.; Gerten, D.; Haddeland, I.; Arnell, N. W.; Clark, D. B.; Dankers, R.; Eisner, S.; Fekete, B. M.; Colon-Gonzalez, F. J.; Gosling, S. N.; KIM, H.; Liu, X.; Masaki, Y.; Portmann, F. T.; Satoh, Y.; Stacke, T.; Tang, Q.; Wada, Y.; Wisser, D.; albrecht, T.; Frieler, K.; Piontek, F.; Warszawski, L.; Kabat, P.

2013-12-01

Water scarcity severely impairs food security and economic prosperity in many countries today. Expected future population changes will, in many countries as well as globally, increase the pressure on available water resources. On the supply side, renewable water resources will be affected by projected changes in precipitation patterns, temperature, and other climate variables. In the framework of the Inter-Sectoral Impact Model Intercomparison Project (ISI-MIP) we use a large ensemble of global hydrological models (GHMs) forced by five global climate models (GCMs) and the latest greenhouse--gas concentration scenarios (RCPs) to synthesize the current knowledge about climate change impacts on water resources. We show that climate change is likely to exacerbate regional and global water scarcity considerably. In particular, the ensemble average projects that up to a global warming of 2°C above present (approx. 2.7°C above pre--industrial), each additional degree of warming will confront an additional approx. 7% of the global population with a severe decrease in water resources; and that climate change will increase the number of people living under absolute water scarcity (<500m3/capita/year) by another 40% (according to some models, more than 100%) compared to the effect of population growth alone. For some indicators of moderate impacts, the steepest increase is seen between present--day and 2°C, while indicators of very severe impacts increase unabated beyond 2°C. At the same time, the study highlights large uncertainties associated with these estimates, with both GCMs and GHMs contributing to the spread. GHM uncertainty is particularly dominant in many regions affected by declining water resources, suggesting a high potential for improved water resource projections through hydrological model development. Relative change in annual discharge at 2°C compared to present-day, under RCP8.5, from an ensemble of 11 global hydrological models (GHMs) driven by five global climate models (GCMs). Color hues show the multi-model mean change, and saturation shows the agreement on the sign of change across all GHM-GCM combinations (percentage of model runs agreeing on the sign).

Regional and seasonal response of a West Nile virus vector to climate change.

PubMed

Morin, Cory W; Comrie, Andrew C

2013-09-24

Climate change will affect the abundance and seasonality of West Nile virus (WNV) vectors, altering the risk of virus transmission to humans. Using downscaled general circulation model output, we calculate a WNV vector's response to climate change across the southern United States using process-based modeling. In the eastern United States, Culex quinquefasciatus response to projected climate change displays a latitudinal and elevational gradient. Projected summer population depressions as a result of increased immature mortality and habitat drying are most severe in the south and almost absent further north; extended spring and fall survival is ubiquitous. Much of California also exhibits a bimodal pattern. Projected onset of mosquito season is delayed in the southwestern United States because of extremely dry and hot spring and summers; however, increased temperature and late summer and fall rains extend the mosquito season. These results are unique in being a broad-scale calculation of the projected impacts of climate change on a WNV vector. The results show that, despite projected widespread future warming, the future seasonal response of C. quinquefasciatus populations across the southern United States will not be homogeneous, and will depend on specific combinations of local and regional conditions.

Ability of matrix models to explain the past and predict the future of plant populations.

USGS Publications Warehouse

McEachern, Kathryn; Crone, Elizabeth E.; Ellis, Martha M.; Morris, William F.; Stanley, Amanda; Bell, Timothy; Bierzychudek, Paulette; Ehrlen, Johan; Kaye, Thomas N.; Knight, Tiffany M.; Lesica, Peter; Oostermeijer, Gerard; Quintana-Ascencio, Pedro F.; Ticktin, Tamara; Valverde, Teresa; Williams, Jennifer I.; Doak, Daniel F.; Ganesan, Rengaian; Thorpe, Andrea S.; Menges, Eric S.

2013-01-01

Uncertainty associated with ecological forecasts has long been recognized, but forecast accuracy is rarely quantified. We evaluated how well data on 82 populations of 20 species of plants spanning 3 continents explained and predicted plant population dynamics. We parameterized stage-based matrix models with demographic data from individually marked plants and determined how well these models forecast population sizes observed at least 5 years into the future. Simple demographic models forecasted population dynamics poorly; only 40% of observed population sizes fell within our forecasts' 95% confidence limits. However, these models explained population dynamics during the years in which data were collected; observed changes in population size during the data-collection period were strongly positively correlated with population growth rate. Thus, these models are at least a sound way to quantify population status. Poor forecasts were not associated with the number of individual plants or years of data. We tested whether vital rates were density dependent and found both positive and negative density dependence. However, density dependence was not associated with forecast error. Forecast error was significantly associated with environmental differences between the data collection and forecast periods. To forecast population fates, more detailed models, such as those that project how environments are likely to change and how these changes will affect population dynamics, may be needed. Such detailed models are not always feasible. Thus, it may be wiser to make risk-averse decisions than to expect precise forecasts from models.

Ability of matrix models to explain the past and predict the future of plant populations.

PubMed

Crone, Elizabeth E; Ellis, Martha M; Morris, William F; Stanley, Amanda; Bell, Timothy; Bierzychudek, Paulette; Ehrlén, Johan; Kaye, Thomas N; Knight, Tiffany M; Lesica, Peter; Oostermeijer, Gerard; Quintana-Ascencio, Pedro F; Ticktin, Tamara; Valverde, Teresa; Williams, Jennifer L; Doak, Daniel F; Ganesan, Rengaian; McEachern, Kathyrn; Thorpe, Andrea S; Menges, Eric S

2013-10-01

Uncertainty associated with ecological forecasts has long been recognized, but forecast accuracy is rarely quantified. We evaluated how well data on 82 populations of 20 species of plants spanning 3 continents explained and predicted plant population dynamics. We parameterized stage-based matrix models with demographic data from individually marked plants and determined how well these models forecast population sizes observed at least 5 years into the future. Simple demographic models forecasted population dynamics poorly; only 40% of observed population sizes fell within our forecasts' 95% confidence limits. However, these models explained population dynamics during the years in which data were collected; observed changes in population size during the data-collection period were strongly positively correlated with population growth rate. Thus, these models are at least a sound way to quantify population status. Poor forecasts were not associated with the number of individual plants or years of data. We tested whether vital rates were density dependent and found both positive and negative density dependence. However, density dependence was not associated with forecast error. Forecast error was significantly associated with environmental differences between the data collection and forecast periods. To forecast population fates, more detailed models, such as those that project how environments are likely to change and how these changes will affect population dynamics, may be needed. Such detailed models are not always feasible. Thus, it may be wiser to make risk-averse decisions than to expect precise forecasts from models. © 2013 Society for Conservation Biology.

Drivers of seabird population recovery on New Zealand islands after predator eradication.

PubMed

Buxton, Rachel T; Jones, Christopher; Moller, Henrik; Towns, David R

2014-04-01

Eradication of introduced mammalian predators from islands has become increasingly common, with over 800 successful projects around the world. Historically, introduced predators extirpated or reduced the size of many seabird populations, changing the dynamics of entire island ecosystems. Although the primary outcome of many eradication projects is the restoration of affected seabird populations, natural population responses are rarely documented and mechanisms are poorly understood. We used a generic model of seabird colony growth to identify key predictor variables relevant to recovery or recolonization. We used generalized linear mixed models to test the importance of these variables in driving seabird population responses after predator eradication on islands around New Zealand. The most influential variable affecting recolonization of seabirds around New Zealand was the distance to a source population, with few cases of recolonization without a source population ≤25 km away. Colony growth was most affected by metapopulation status; there was little colony growth in species with a declining status. These characteristics may facilitate the prioritization of newly predator-free islands for active management. Although we found some evidence documenting natural recovery, generally this topic was understudied. Our results suggest that in order to guide management strategies, more effort should be allocated to monitoring wildlife response after eradication. © 2014 Society for Conservation Biology.

The impact of accelerating faster than exponential population growth on genetic variation.

PubMed

Reppell, Mark; Boehnke, Michael; Zöllner, Sebastian

2014-03-01

Current human sequencing projects observe an abundance of extremely rare genetic variation, suggesting recent acceleration of population growth. To better understand the impact of such accelerating growth on the quantity and nature of genetic variation, we present a new class of models capable of incorporating faster than exponential growth in a coalescent framework. Our work shows that such accelerated growth affects only the population size in the recent past and thus large samples are required to detect the models' effects on patterns of variation. When we compare models with fixed initial growth rate, models with accelerating growth achieve very large current population sizes and large samples from these populations contain more variation than samples from populations with constant growth. This increase is driven almost entirely by an increase in singleton variation. Moreover, linkage disequilibrium decays faster in populations with accelerating growth. When we instead condition on current population size, models with accelerating growth result in less overall variation and slower linkage disequilibrium decay compared to models with exponential growth. We also find that pairwise linkage disequilibrium of very rare variants contains information about growth rates in the recent past. Finally, we demonstrate that models of accelerating growth may substantially change estimates of present-day effective population sizes and growth times.

Past and ongoing shifts in Joshua tree distribution support future modeled range contraction

USGS Publications Warehouse

Cole, Kenneth L.; Ironside, Kirsten; Eischeid, Jon K.; Garfin, Gregg; Duffy, Phil; Toney, Chris

2011-01-01

The future distribution of the Joshua tree (Yucca brevifolia) is projected by combining a geostatistical analysis of 20th-century climates over its current range, future modeled climates, and paleoecological data showing its response to a past similar climate change. As climate rapidly warmed ;11 700 years ago, the range of Joshua tree contracted, leaving only the populations near what had been its northernmost limit. Its ability to spread northward into new suitable habitats after this time may have been inhibited by the somewhat earlier extinction of megafaunal dispersers, especially the Shasta ground sloth. We applied a model of climate suitability for Joshua tree, developed from its 20th-century range and climates, to future climates modeled through a set of six individual general circulation models (GCM) and one suite of 22 models for the late 21st century. All distribution data, observed climate data, and future GCM results were scaled to spatial grids of ;1 km and ;4 km in order to facilitate application within this topographically complex region. All of the models project the future elimination of Joshua tree throughout most of the southern portions of its current range. Although estimates of future monthly precipitation differ between the models, these changes are outweighed by large increases in temperature common to all the models. Only a few populations within the current range are predicted to be sustainable. Several models project significant potential future expansion into new areas beyond the current range, but the species' Historical and current rates of dispersal would seem to prevent natural expansion into these new areas. Several areas are predicted to be potential sites for relocation/ assisted migration. This project demonstrates how information from paleoecology and modern ecology can be integrated in order to understand ongoing processes and future distributions.

Bayesian Population Forecasting: Extending the Lee-Carter Method.

PubMed

Wiśniowski, Arkadiusz; Smith, Peter W F; Bijak, Jakub; Raymer, James; Forster, Jonathan J

2015-06-01

In this article, we develop a fully integrated and dynamic Bayesian approach to forecast populations by age and sex. The approach embeds the Lee-Carter type models for forecasting the age patterns, with associated measures of uncertainty, of fertility, mortality, immigration, and emigration within a cohort projection model. The methodology may be adapted to handle different data types and sources of information. To illustrate, we analyze time series data for the United Kingdom and forecast the components of population change to the year 2024. We also compare the results obtained from different forecast models for age-specific fertility, mortality, and migration. In doing so, we demonstrate the flexibility and advantages of adopting the Bayesian approach for population forecasting and highlight areas where this work could be extended.

Projecting the success of plant restoration with population viability analysis

USGS Publications Warehouse

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 two plant species listed in the USA for which federal recovery planning calls for population restoration: Cirsium pitcheri, a short-lived semelparous herb, and Asclepias meadii, a long-lived iteroparous herb.

Integral projection models for finite populations in a stochastic environment.

PubMed

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.

Climate change enhances interannual variability of the Nile river flow

NASA Astrophysics Data System (ADS)

Siam, Mohamed S.; Eltahir, Elfatih A. B.

2017-04-01

The human population living in the Nile basin countries is projected to double by 2050, approaching one billion. The increase in water demand associated with this burgeoning population will put significant stress on the available water resources. Potential changes in the flow of the Nile River as a result of climate change may further strain this critical situation. Here, we present empirical evidence from observations and consistent projections from climate model simulations suggesting that the standard deviation describing interannual variability of total Nile flow could increase by 50% (+/-35%) (multi-model ensemble mean +/- 1 standard deviation) in the twenty-first century compared to the twentieth century. We attribute the relatively large change in interannual variability of the Nile flow to projected increases in future occurrences of El Niño and La Niña events and to observed teleconnection between the El Niño-Southern Oscillation and Nile River flow. Adequacy of current water storage capacity and plans for additional storage capacity in the basin will need to be re-evaluated given the projected enhancement of interannual variability in the future flow of the Nile river.

Cost-effectiveness of diabetes case management for low-income populations.

PubMed

Gilmer, Todd P; Roze, Stéphane; Valentine, William J; Emy-Albrecht, Katrina; Ray, Joshua A; Cobden, David; Nicklasson, Lars; Philis-Tsimikas, Athena; Palmer, Andrew J

2007-10-01

To evaluate the cost-effectiveness of Project Dulce, a culturally specific diabetes case management and self-management training program, in four cohorts defined by insurance status. Clinical and cost data on 3,893 persons with diabetes participating in Project Dulce were used as inputs into a diabetes simulation model. The Center for Outcomes Research Diabetes Model, a published, peer-reviewed and validated simulation model of diabetes, was used to evaluate life expectancy, quality-adjusted life expectancy (QALY), cumulative incidence of complications and direct medical costs over patient lifetimes (40-year time horizon) from a third-party payer perspective. Cohort characteristics, treatment effects, and case management costs were derived using a difference in difference design comparing data from the Project Dulce program to a cohort of historical controls. Long-term costs were derived from published U.S. sources. Costs and clinical benefits were discounted at 3.0 percent per annum. Sensitivity analyses were performed. Incremental cost-effectiveness ratios of $10,141, $24,584, $44,941, and $69,587 per QALY gained were estimated for Project Dulce participants versus control in the uninsured, County Medical Services, Medi-Cal, and commercial insurance cohorts, respectively. The Project Dulce diabetes case management program was associated with cost-effective improvements in quality-adjusted life expectancy and decreased incidence of diabetes-related complications over patient lifetimes. Diabetes case management may be particularly cost effective for low-income populations.

WATER SUPPLY PIPE REPLACEMENT CONSIDERING SUSTAINABLE TRANSITION TO POPULATION DECREASED SOCIETY

NASA Astrophysics Data System (ADS)

Hosoi, Yoshihiko; Iwasaki, Yoji; Aklog, Dagnachew; Masuda, Takanori

Social infrastructures are aging and population is decreasing in Japan. The aged social infrastructures should be renewed. At the same time, they are required to be moved into new framework suitable for population decreased societies. Furthermore, they have to continue to supply sufficient services even during transition term that renewal projects are carried out. Authors propose sustainable soft landing management of infrastructures and it is tried to apply to water supply pipe replacement in this study. Methodology to replace aged pipes not only aiming for the new water supply network which suits for population decreased condition but also ensuring supply service and feasibility while the project is carried out was developed. It is applied for a model water supply network and discussions were carried out.

Current and Projected Heat-Related Morbidity and Mortality in Rhode Island.

PubMed

Kingsley, Samantha L; Eliot, Melissa N; Gold, Julia; Vanderslice, Robert R; Wellenius, Gregory A

2016-04-01

Climate change is expected to cause increases in heat-related mortality, especially among the elderly and very young. However, additional studies are needed to clarify the effects of heat on morbidity across all age groups and across a wider range of temperatures. We aimed to estimate the impact of current and projected future temperatures on morbidity and mortality in Rhode Island. We used Poisson regression models to estimate the association between daily maximum temperature and rates of all-cause and heat-related emergency department (ED) admissions and all-cause mortality. We then used downscaled Coupled Model Intercomparison Project Phase 5 (CMIP5; a standardized set of climate change model simulations) projections to estimate the excess morbidity and mortality that would be observed if this population were exposed to the temperatures projected for 2046-2053 and 2092-2099 under two representative concentration pathways (RCP): RCP 8.5 and 4.5. Between 2005 and 2012, an increase in maximum daily temperature from 75 to 85°F was associated with 1.3% and 23.9% higher rates of all-cause and heat-related ED visits, respectively. The corresponding effect estimate for all-cause mortality from 1999 through 2011 was 4.0%. The association with all-cause ED admissions was strongest for those < 18 or ≥ 65 years of age, whereas the association with heat-related ED admissions was most pronounced among 18- to 64-year-olds. If this Rhode Island population were exposed to temperatures projected under RCP 8.5 for 2092-2099, we estimate that there would be 1.2% (range, 0.6-1.6%) and 24.4% (range, 6.9-41.8%) more all-cause and heat-related ED admissions, respectively, and 1.6% (range, 0.8-2.1%) more deaths annually between April and October. With all other factors held constant, our findings suggest that the current population of Rhode Island would experience substantially higher morbidity and mortality if maximum daily temperatures increase further as projected. Kingsley SL, Eliot MN, Gold J, Vanderslice RR, Wellenius GA. 2016. Current and projected heat-related morbidity and mortality in Rhode Island. Environ Health Perspect 124:460-467; http://dx.doi.org/10.1289/ehp.1408826.

Multiple sclerosis in Canada 2011 to 2031: results of a microsimulation modelling study of epidemiological and economic impacts.

PubMed

Amankwah, Nana; Marrie, Ruth Ann; Bancej, Christina; Garner, Rochelle; Manuel, Douglas G; Wall, Ron; Finès, Philippe; Bernier, Julie; Tu, Karen; Reimer, Kim

2017-02-01

The objective of our study was to present model-based estimates and projections on current and future health and economic impacts of multiple sclerosis (MS) in Canada over a 20-year time horizon (2011-2031). Using Statistics Canada's Population Health Microsimulation Model (POHEM) framework, specifically the population-based longitudinal, microsimulation model named POHEM-Neurological, we identified people with MS from health administrative data sources and derived incidence and mortality rate parameters from a British Columbia population-based cohort for future MS incidence and mortality projections. We also included a utility-based measure (Health Utilities Index Mark 3) reflecting states of functional health to allow projections of health-related quality of life. Finally, we estimated caregiving parameters and health care costs from Canadian national surveys and health administrative data and included them as model parameters to assess the health and economic impact of the neurological conditions. The number of incident MS cases is expected to rise slightly from 4051 cases in 2011 to 4794 cases per 100 000 population in 2031, and the number of Canadians affected by MS will increase from 98 385 in 2011 to 133 635 in 2031. The total per capita health care cost (excluding out-of-pocket expenses) for adults aged 20 and older in 2011 was about $16 800 for individuals with MS, and approximately $2500 for individuals without a neurological condition. Thus, after accounting for additional expenditures due to MS (excluding out-of-pocket expenses), total annual health sector costs for MS are expected to reach $2.0 billion by 2031. As well, the average out-of-pocket expenditure for people with MS was around $1300 annually throughout the projection period. MS is associated with a significant economic burden on society, since it usually affects young adults during prime career- and family-building years. Canada has a particularly high prevalence of MS, so research such as the present study is essential to provide a better understanding of the current and future negative impacts of MS on the Canadian population, so that health care system policymakers can best plan how to meet the needs of patients who are affected by MS. These findings also suggest that identifying strategies to prevent MS and more effectively treat the disease are needed to mitigate these future impacts.

Multiple sclerosis in Canada 2011 to 2031: results of a microsimulation modelling study of epidemiological and economic impacts

PubMed Central

Nana, Amankwah; Ruth, Ann Marrie; Christina, Bancej; Rochelle, Garner; Douglas, G. Manuel; Ron, Wall; Philippe, Finès; Julie, Bernier; Karen, Tu; Kim, Reimer

2017-01-01

Introduction: The objective of our study was to present model-based estimates and projections on current and future health and economic impacts of multiple sclerosis (MS) in Canada over a 20-year time horizon (2011–2031). Methods: Using Statistics Canada’s Population Health Microsimulation Model (POHEM) framework, specifically the population-based longitudinal, microsimulation model named POHEM-Neurological, we identified people with MS from health administrative data sources and derived incidence and mortality rate parameters from a British Columbia population-based cohort for future MS incidence and mortality projections. We also included a utility-based measure (Health Utilities Index Mark 3) reflecting states of functional health to allow projections of health-related quality of life. Finally, we estimated caregiving parameters and health care costs from Canadian national surveys and health administrative data and included them as model parameters to assess the health and economic impact of the neurological conditions. Results: The number of incident MS cases is expected to rise slightly from 4051 cases in 2011 to 4794 cases per 100 000 population in 2031, and the number of Canadians affected by MS will increase from 98 385 in 2011 to 133 635 in 2031. The total per capita health care cost (excluding out-of-pocket expenses) for adults aged 20 and older in 2011 was about $16 800 for individuals with MS, and approximately $2500 for individuals without a neurological condition. Thus, after accounting for additional expenditures due to MS (excluding out-of-pocket expenses), total annual health sector costs for MS are expected to reach $2.0 billion by 2031. As well, the average out-of-pocket expenditure for people with MS was around $1300 annually throughout the projection period. Conclusion: MS is associated with a significant economic burden on society, since it usually affects young adults during prime career- and family-building years. Canada has a particularly high prevalence of MS, so research such as the present study is essential to provide a better understanding of the current and future negative impacts of MS on the Canadian population, so that health care system policymakers can best plan how to meet the needs of patients who are affected by MS. These findings also suggest that identifying strategies to prevent MS and more effectively treat the disease are needed to mitigate these future impacts. PMID:28273039

Building integral projection models: a user's guide

PubMed Central

Rees, Mark; Childs, Dylan Z; Ellner, Stephen P; Coulson, Tim

2014-01-01

In order to understand how changes in individual performance (growth, survival or reproduction) influence population dynamics and evolution, ecologists are increasingly using parameterized mathematical models. For continuously structured populations, where some continuous measure of individual state influences growth, survival or reproduction, integral projection models (IPMs) are commonly used. We provide a detailed description of the steps involved in constructing an IPM, explaining how to: (i) translate your study system into an IPM; (ii) implement your IPM; and (iii) diagnose potential problems with your IPM. We emphasize how the study organism's life cycle, and the timing of censuses, together determine the structure of the IPM kernel and important aspects of the statistical analysis used to parameterize an IPM using data on marked individuals. An IPM based on population studies of Soay sheep is used to illustrate the complete process of constructing, implementing and evaluating an IPM fitted to sample data. We then look at very general approaches to parameterizing an IPM, using a wide range of statistical techniques (e.g. maximum likelihood methods, generalized additive models, nonparametric kernel density estimators). Methods for selecting models for parameterizing IPMs are briefly discussed. We conclude with key recommendations and a brief overview of applications that extend the basic model. The online Supporting Information provides commented R code for all our analyses. PMID:24219157

Development of a Web-Accessible Population Pharmacokinetic Service-Hemophilia (WAPPS-Hemo): Study Protocol.

PubMed

Iorio, Alfonso; Keepanasseril, Arun; Foster, Gary; Navarro-Ruan, Tamara; McEneny-King, Alanna; Edginton, Andrea N; Thabane, Lehana

2016-12-15

Individual pharmacokinetic assessment is a critical component of tailored prophylaxis for hemophilia patients. Population pharmacokinetics allows using individual sparse data, thus simplifying individual pharmacokinetic studies. Implementing population pharmacokinetics capacity for the hemophilia community is beyond individual reach and requires a system effort. The Web-Accessible Population Pharmacokinetic Service-Hemophilia (WAPPS-Hemo) project aims to assemble a database of patient pharmacokinetic data for all existing factor concentrates, develop and validate population pharmacokinetics models, and integrate these models within a Web-based calculator for individualized pharmacokinetic estimation in patients at participating treatment centers. Individual pharmacokinetic studies on factor VIII and IX concentrates will be sourced from pharmaceutical companies and independent investigators. All factor concentrate manufacturers, hemophilia treatment centers (HTCs), and independent investigators (identified via a systematic review of the literature) having on file pharmacokinetic data and willing to contribute full or sparse pharmacokinetic data will be eligible for participation. Multicompartmental modeling will be performed using a mixed-model approach for derivation and Bayesian forecasting for estimation of individual sparse data. NONMEM (ICON Development Solutions) will be used as modeling software. The WAPPS-Hemo research network has been launched and is currently joined by 30 HTCs from across the world. We have gathered dense individual pharmacokinetic data on 878 subjects, including several replicates, on 21 different molecules from 17 different sources. We have collected sparse individual pharmacokinetic data on 289 subjects from the participating centers through the testing phase of the WAPPS-Hemo Web interface. We have developed prototypal population pharmacokinetics models for 11 molecules. The WAPPS-Hemo website (available at www.wapps-hemo.org, version 2.4), with core functionalities allowing hemophilia treaters to obtain individual pharmacokinetic estimates on sparse data points after 1 or more infusions of a factor concentrate, was launched for use within the research network in July 2015. The WAPPS-Hemo project and research network aims to make it easier to perform individual pharmacokinetic assessments on a reduced number of plasma samples by adoption of a population pharmacokinetics approach. The project will also gather data to substantially enhance the current knowledge about factor concentrate pharmacokinetics and sources of its variability in target populations. ClinicalTrials.gov NCT02061072; https://clinicaltrials.gov/ct2/show/NCT02061072 (Archived by WebCite at http://www.webcitation.org/6mRK9bKP6). ©Alfonso Iorio, Arun Keepanasseril, Gary Foster, Tamara Navarro-Ruan, Alanna McEneny-King, Andrea N Edginton, Lehana Thabane. Originally published in JMIR Research Protocols (http://www.researchprotocols.org), 15.12.2016.

Data for Environmental Modeling (D4EM): Background and Applications of Data Automation

EPA Science Inventory

The Data for Environmental Modeling (D4EM) project demonstrates the development of a comprehensive set of open source software tools that overcome obstacles to accessing data needed by automating the process of populating model input data sets with environmental data available fr...

Influence of internal variability on population exposure to hydroclimatic changes

NASA Astrophysics Data System (ADS)

Mankin, Justin S.; Viviroli, Daniel; Mekonnen, Mesfin M.; Hoekstra, Arjen Y.; Horton, Radley M.; E Smerdon, Jason; Diffenbaugh, Noah S.

2017-04-01

Future freshwater supply, human water demand, and people’s exposure to water stress are subject to multiple sources of uncertainty, including unknown future pathways of fossil fuel and water consumption, and ‘irreducible’ uncertainty arising from internal climate system variability. Such internal variability can conceal forced hydroclimatic changes on multi-decadal timescales and near-continental spatial-scales. Using three projections of population growth, a large ensemble from a single Earth system model, and assuming stationary per capita water consumption, we quantify the likelihoods of future population exposure to increased hydroclimatic deficits, which we define as the average duration and magnitude by which evapotranspiration exceeds precipitation in a basin. We calculate that by 2060, ∽31%-35% of the global population will be exposed to >50% probability of hydroclimatic deficit increases that exceed existing hydrological storage, with up to 9% of people exposed to >90% probability. However, internal variability, which is an irreducible uncertainty in climate model predictions that is under-sampled in water resource projections, creates substantial uncertainty in predicted exposure: ∽86%-91% of people will reside where irreducible uncertainty spans the potential for both increases and decreases in sub-annual water deficits. In one population scenario, changes in exposure to large hydroclimate deficits vary from -3% to +6% of global population, a range arising entirely from internal variability. The uncertainty in risk arising from irreducible uncertainty in the precise pattern of hydroclimatic change, which is typically conflated with other uncertainties in projections, is critical for climate risk management that seeks to optimize adaptations that are robust to the full set of potential real-world outcomes.

Computational Models Used to Assess US Tobacco Control Policies.

PubMed

Feirman, Shari P; Glasser, Allison M; Rose, Shyanika; Niaura, Ray; Abrams, David B; Teplitskaya, Lyubov; Villanti, Andrea C

2017-11-01

Simulation models can be used to evaluate existing and potential tobacco control interventions, including policies. The purpose of this systematic review was to synthesize evidence from computational models used to project population-level effects of tobacco control interventions. We provide recommendations to strengthen simulation models that evaluate tobacco control interventions. Studies were eligible for review if they employed a computational model to predict the expected effects of a non-clinical US-based tobacco control intervention. We searched five electronic databases on July 1, 2013 with no date restrictions and synthesized studies qualitatively. Six primary non-clinical intervention types were examined across the 40 studies: taxation, youth prevention, smoke-free policies, mass media campaigns, marketing/advertising restrictions, and product regulation. Simulation models demonstrated the independent and combined effects of these interventions on decreasing projected future smoking prevalence. Taxation effects were the most robust, as studies examining other interventions exhibited substantial heterogeneity with regard to the outcomes and specific policies examined across models. Models should project the impact of interventions on overall tobacco use, including nicotine delivery product use, to estimate preventable health and cost-saving outcomes. Model validation, transparency, more sophisticated models, and modeling policy interactions are also needed to inform policymakers to make decisions that will minimize harm and maximize health. In this systematic review, evidence from multiple studies demonstrated the independent effect of taxation on decreasing future smoking prevalence, and models for other tobacco control interventions showed that these strategies are expected to decrease smoking, benefit population health, and are reasonable to implement from a cost perspective. Our recommendations aim to help policymakers and researchers minimize harm and maximize overall population-level health benefits by considering the real-world context in which tobacco control interventions are implemented. © The Author 2017. Published by Oxford University Press on behalf of the Society for Research on Nicotine and Tobacco. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Model of the songbird nucleus HVC as a network of central pattern generators

PubMed Central

Abarbanel, Henry D. I.

2016-01-01

We propose a functional architecture of the adult songbird nucleus HVC in which the core element is a “functional syllable unit” (FSU). In this model, HVC is organized into FSUs, each of which provides the basis for the production of one syllable in vocalization. Within each FSU, the inhibitory neuron population takes one of two operational states: 1) simultaneous firing wherein all inhibitory neurons fire simultaneously, and 2) competitive firing of the inhibitory neurons. Switching between these basic modes of activity is accomplished via changes in the synaptic strengths among the inhibitory neurons. The inhibitory neurons connect to excitatory projection neurons such that during state 1 the activity of projection neurons is suppressed, while during state 2 patterns of sequential firing of projection neurons can occur. The latter state is stabilized by feedback from the projection to the inhibitory neurons. Song composition for specific species is distinguished by the manner in which different FSUs are functionally connected to each other. Ours is a computational model built with biophysically based neurons. We illustrate that many observations of HVC activity are explained by the dynamics of the proposed population of FSUs, and we identify aspects of the model that are currently testable experimentally. In addition, and standing apart from the core features of an FSU, we propose that the transition between modes may be governed by the biophysical mechanism of neuromodulation. PMID:27535375

Changes in seasonal climate outpace compensatory density-dependence in eastern brook trout

USGS Publications Warehouse

Bassar, Ronald D.; Letcher, Benjamin H.; Nislow, Keith H.; Whiteley, Andrew R.

2016-01-01

Understanding how multiple extrinsic (density-independent) factors and intrinsic (density-dependent) mechanisms influence population dynamics has become increasingly urgent in the face of rapidly changing climates. It is particularly unclear how multiple extrinsic factors with contrasting effects among seasons are related to declines in population numbers and changes in mean body size and whether there is a strong role for density-dependence. The primary goal of this study was to identify the roles of seasonal variation in climate driven environmental direct effects (mean stream flow and temperature) versus density-dependence on population size and mean body size in eastern brook trout (Salvelinus fontinalis). We use data from a 10-year capture-mark-recapture study of eastern brook trout in four streams in Western Massachusetts, USA to parameterize a discrete-time population projection model. The model integrates matrix modeling techniques used to characterize discrete population structures (age, habitat type and season) with integral projection models (IPMs) that characterize demographic rates as continuous functions of organismal traits (in this case body size). Using both stochastic and deterministic analyses we show that decreases in population size are due to changes in stream flow and temperature and that these changes are larger than what can be compensated for through density-dependent responses. We also show that the declines are due mostly to increasing mean stream temperatures decreasing the survival of the youngest age class. In contrast, increases in mean body size over the same period are the result of indirect changes in density with a lesser direct role of climate-driven environmental change.

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

USGS Publications Warehouse

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.

Current and future disease progression of the chronic HCV population in the United States.

PubMed

Zalesak, Martin; Francis, Kevin; Gedeon, Alex; Gillis, John; Hvidsten, Kyle; Kidder, Phyllis; Li, Hong; Martyn, Derek; Orne, Leslie; Smith, Amanda; Kwong, Ann

2013-01-01

Chronic hepatitis C virus (HCV) infection can lead to advanced liver disease (AdvLD), including cirrhosis, decompensated cirrhosis, and liver cancer. The aim of this study was to determine recent historical rates of HCV patient progression to AdvLD and to project AdvLD prevalence through 2015. We first determined total 2008 US chronic HCV prevalence from the National Health and Nutrition Evaluation Surveys. Next, we examined disease progression and associated non-pharmacological costs of diagnosed chronic HCV-infected patients between 2007-2009 in the IMS LifeLink and CMS Medicare claims databases. A projection model was developed to estimate AdvLD population growth through 2015 in patients diagnosed and undiagnosed as of 2008, using the 2007-2009 progression rates to generate a "worst case" projection of the HCV-related AdvLD population (i.e., scenario where HCV treatment is the same in the forecasted period as it was before 2009). We found that the total diagnosed chronic HCV population grew from 983,000 to 1.19 million in 2007-2009, with patients born from 1945-1964 accounting for 75.0% of all patients, 83.7% of AdvLD patients, and 79.2% of costs in 2009, indicating that HCV is primarily a disease of the "baby boomer" population. Non-pharmacological costs grew from $7.22 billion to $8.63 billion, with the majority of growth derived from the 60,000 new patients that developed AdvLD in 2007-2009, 91.5% of whom were born between 1945 and 1964. The projection model estimated the total AdvLD population would grow from 195,000 in 2008 to 601,000 in 2015, with 73.5% of new AdvLD cases from patients undiagnosed as of 2008. AdvLD prevalence in patients diagnosed as of 2008 was projected to grow 6.5% annually to 303,000 patients in 2015. These findings suggest that strategies to diagnose and treat HCV-infected patients are urgently needed to increase the likelihood that progression is interrupted, particularly for patients born from 1945-1964.

Multimodel assessment of water scarcity under climate change.

PubMed

Schewe, Jacob; Heinke, Jens; Gerten, Dieter; Haddeland, Ingjerd; Arnell, Nigel W; Clark, Douglas B; Dankers, Rutger; Eisner, Stephanie; Fekete, Balázs M; Colón-González, Felipe J; Gosling, Simon N; Kim, Hyungjun; Liu, Xingcai; Masaki, Yoshimitsu; Portmann, Felix T; Satoh, Yusuke; Stacke, Tobias; Tang, Qiuhong; Wada, Yoshihide; Wisser, Dominik; Albrecht, Torsten; Frieler, Katja; Piontek, Franziska; Warszawski, Lila; Kabat, Pavel

2014-03-04

Water scarcity severely impairs food security and economic prosperity in many countries today. Expected future population changes will, in many countries as well as globally, increase the pressure on available water resources. On the supply side, renewable water resources will be affected by projected changes in precipitation patterns, temperature, and other climate variables. Here we use a large ensemble of global hydrological models (GHMs) forced by five global climate models and the latest greenhouse-gas concentration scenarios (Representative Concentration Pathways) to synthesize the current knowledge about climate change impacts on water resources. We show that climate change is likely to exacerbate regional and global water scarcity considerably. In particular, the ensemble average projects that a global warming of 2 °C above present (approximately 2.7 °C above preindustrial) will confront an additional approximate 15% of the global population with a severe decrease in water resources and will increase the number of people living under absolute water scarcity (<500 m(3) per capita per year) by another 40% (according to some models, more than 100%) compared with the effect of population growth alone. For some indicators of moderate impacts, the steepest increase is seen between the present day and 2 °C, whereas indicators of very severe impacts increase unabated beyond 2 °C. At the same time, the study highlights large uncertainties associated with these estimates, with both global climate models and GHMs contributing to the spread. GHM uncertainty is particularly dominant in many regions affected by declining water resources, suggesting a high potential for improved water resource projections through hydrological model development.

Multimodel assessment of water scarcity under climate change

PubMed Central

Schewe, Jacob; Heinke, Jens; Gerten, Dieter; Haddeland, Ingjerd; Arnell, Nigel W.; Clark, Douglas B.; Dankers, Rutger; Eisner, Stephanie; Fekete, Balázs M.; Colón-González, Felipe J.; Gosling, Simon N.; Kim, Hyungjun; Liu, Xingcai; Masaki, Yoshimitsu; Portmann, Felix T.; Satoh, Yusuke; Stacke, Tobias; Tang, Qiuhong; Wada, Yoshihide; Wisser, Dominik; Albrecht, Torsten; Frieler, Katja; Piontek, Franziska; Warszawski, Lila; Kabat, Pavel

2014-01-01

Water scarcity severely impairs food security and economic prosperity in many countries today. Expected future population changes will, in many countries as well as globally, increase the pressure on available water resources. On the supply side, renewable water resources will be affected by projected changes in precipitation patterns, temperature, and other climate variables. Here we use a large ensemble of global hydrological models (GHMs) forced by five global climate models and the latest greenhouse-gas concentration scenarios (Representative Concentration Pathways) to synthesize the current knowledge about climate change impacts on water resources. We show that climate change is likely to exacerbate regional and global water scarcity considerably. In particular, the ensemble average projects that a global warming of 2 °C above present (approximately 2.7 °C above preindustrial) will confront an additional approximate 15% of the global population with a severe decrease in water resources and will increase the number of people living under absolute water scarcity (<500 m3 per capita per year) by another 40% (according to some models, more than 100%) compared with the effect of population growth alone. For some indicators of moderate impacts, the steepest increase is seen between the present day and 2 °C, whereas indicators of very severe impacts increase unabated beyond 2 °C. At the same time, the study highlights large uncertainties associated with these estimates, with both global climate models and GHMs contributing to the spread. GHM uncertainty is particularly dominant in many regions affected by declining water resources, suggesting a high potential for improved water resource projections through hydrological model development. PMID:24344289

Differential loss of striatal projection neurons in Huntington disease

DOE Office of Scientific and Technical Information (OSTI.GOV)

Reiner, A.; Albin, R.L.; Anderson, K.D.

1988-08-01

Huntington disease (HD) is characterized by the loss of striatal projection neurons, which constitute the vast majority of striatal neurons. To determine whether there is differential loss among different populations of striatal projection neurons, the integrity of the axon terminal plexuses arising from the different populations of substance P-containing and enkephalin-containing striatal projection neurons was studied in striatal target areas by immunohistochemistry. Analysis of 17 HD specimens indicated that in early and middle stages of HD, enkephalin-containing neurons projecting to the external segment of the globus pallidus were much more affected than substance P-containing neurons projecting to the internal pallidalmore » segment. Furthermore, substance P-containing neurons projecting to the substantia nigra pars reticulata were more affected than those projecting to the substantia nigra pars compacta. At the most advanced stages of the disease, projections to all striatal target areas were depleted, with the exception of some apparent sparing of the striatal projection to the substantia nigra pars compacta. These finding may explain some of the clinical manifestations and pharmacology of HD. They also may aid in identifying the neural defect underlying HD and provide additional data with which to evaluate current models of HD pathogenesis.« less

The southern megalopolis: using the past to predict the future of urban sprawl in the Southeast U.S.

USGS Publications Warehouse

Terando, Adam; Costanza, Jennifer; Belyea, Curtis; Dunn, Robert R.; McKerrow, Alexa; Collazo, Jaime

2014-01-01

The future health of ecosystems is arguably as dependent on urban sprawl as it is on human-caused climatic warming. Urban sprawl strongly impacts the urban ecosystems it creates and the natural and agro-ecosystems that it displaces and fragments. Here, we project urban sprawl changes for the next 50 years for the fast-growing Southeast U.S. Previous studies have focused on modeling population density, but the urban extent is arguably as important as population density per se in terms of its ecological and conservation impacts. We develop simulations using the SLEUTH urban growth model that complement population-driven models but focus on spatial pattern and extent. To better capture the reach of low-density suburban development, we extend the capabilities of SLEUTH by incorporating street-network information. Our simulations point to a future in which the extent of urbanization in the Southeast is projected to increase by 101% to 192%. Our results highlight areas where ecosystem fragmentation is likely, and serve as a benchmark to explore the challenging tradeoffs between ecosystem health, economic growth and cultural desires.

The Southern Megalopolis: Using the Past to Predict the Future of Urban Sprawl in the Southeast U.S

PubMed Central

Terando, Adam J.; Costanza, Jennifer; Belyea, Curtis; Dunn, Robert R.; McKerrow, Alexa; Collazo, Jaime A.

2014-01-01

The future health of ecosystems is arguably as dependent on urban sprawl as it is on human-caused climatic warming. Urban sprawl strongly impacts the urban ecosystems it creates and the natural and agro-ecosystems that it displaces and fragments. Here, we project urban sprawl changes for the next 50 years for the fast-growing Southeast U.S. Previous studies have focused on modeling population density, but the urban extent is arguably as important as population density per se in terms of its ecological and conservation impacts. We develop simulations using the SLEUTH urban growth model that complement population-driven models but focus on spatial pattern and extent. To better capture the reach of low-density suburban development, we extend the capabilities of SLEUTH by incorporating street-network information. Our simulations point to a future in which the extent of urbanization in the Southeast is projected to increase by 101% to 192%. Our results highlight areas where ecosystem fragmentation is likely, and serve as a benchmark to explore the challenging tradeoffs between ecosystem health, economic growth and cultural desires. PMID:25054329

A modeling framework for evaluating the drought resilience of a surface water supply system under non-stationarity

DOE PAGES

Zhao, Gang; Gao, Huilin; Kao, Shih -Chieh; ...

2018-05-23

Here, the future resilience of water supply systems is unprecedentedly challenged by non-stationary processes, such as fast population growth and a changing climate. A thorough understanding of how these non-stationarities impact water supply resilience is vital to support sustainable decision making, particularly for large cities in arid and/or semi-arid regions. In this study, a novel modeling framework, which integrates hydrological processes and water management, was established over a representative water limited metropolitan area to evaluate the impacts of water availability and water demand on reservoir storage and water supply reliability. In this framework, climate change induced drought events were selectedmore » from statistically downscaled Coupled Model Intercomparison Project Phase 5 outputs under the Representative Concentration Pathway 8.5 scenario, while future water demand was estimated by the product of projected future population and per capita water use. Compared with the first half of the 21st century (2000–2049), reservoir storage and water supply reliability during the second half century (2050–2099) are projected to reduce by 16.1% and 14.2%, respectively. While both future multi-year droughts and population growth will lower water supply resilience, the uncertainty associated with future climate projection is larger than that associated with urbanization. To reduce the drought risks, a combination of mitigation strategies (e.g., additional conservation, integrating new water sources, and water use redistribution) was found to be the most efficient approach and can significantly improve water supply reliability by as much as 15.9%.« less

A modeling framework for evaluating the drought resilience of a surface water supply system under non-stationarity

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhao, Gang; Gao, Huilin; Kao, Shih -Chieh

Here, the future resilience of water supply systems is unprecedentedly challenged by non-stationary processes, such as fast population growth and a changing climate. A thorough understanding of how these non-stationarities impact water supply resilience is vital to support sustainable decision making, particularly for large cities in arid and/or semi-arid regions. In this study, a novel modeling framework, which integrates hydrological processes and water management, was established over a representative water limited metropolitan area to evaluate the impacts of water availability and water demand on reservoir storage and water supply reliability. In this framework, climate change induced drought events were selectedmore » from statistically downscaled Coupled Model Intercomparison Project Phase 5 outputs under the Representative Concentration Pathway 8.5 scenario, while future water demand was estimated by the product of projected future population and per capita water use. Compared with the first half of the 21st century (2000–2049), reservoir storage and water supply reliability during the second half century (2050–2099) are projected to reduce by 16.1% and 14.2%, respectively. While both future multi-year droughts and population growth will lower water supply resilience, the uncertainty associated with future climate projection is larger than that associated with urbanization. To reduce the drought risks, a combination of mitigation strategies (e.g., additional conservation, integrating new water sources, and water use redistribution) was found to be the most efficient approach and can significantly improve water supply reliability by as much as 15.9%.« less

The Impact of Accelerating Faster than Exponential Population Growth on Genetic Variation

PubMed Central

Reppell, Mark; Boehnke, Michael; Zöllner, Sebastian

2014-01-01

Current human sequencing projects observe an abundance of extremely rare genetic variation, suggesting recent acceleration of population growth. To better understand the impact of such accelerating growth on the quantity and nature of genetic variation, we present a new class of models capable of incorporating faster than exponential growth in a coalescent framework. Our work shows that such accelerated growth affects only the population size in the recent past and thus large samples are required to detect the models’ effects on patterns of variation. When we compare models with fixed initial growth rate, models with accelerating growth achieve very large current population sizes and large samples from these populations contain more variation than samples from populations with constant growth. This increase is driven almost entirely by an increase in singleton variation. Moreover, linkage disequilibrium decays faster in populations with accelerating growth. When we instead condition on current population size, models with accelerating growth result in less overall variation and slower linkage disequilibrium decay compared to models with exponential growth. We also find that pairwise linkage disequilibrium of very rare variants contains information about growth rates in the recent past. Finally, we demonstrate that models of accelerating growth may substantially change estimates of present-day effective population sizes and growth times. PMID:24381333

Economic Impact of a Medicaid Population Health Management Program

PubMed Central

Strothers, Harry; Miller, William Johnson; McLaren, Susan; Moore, Barbara; Sambamoorthi, Usha

2011-01-01

Abstract A population health management program was implemented to assess growth in health care expenditures for the disabled segment of Georgia's Medicaid population before and during the first year of a population health outcomes management program, and to compare those expenditures with projected costs based on various cost inflation trend assumptions. A retrospective, nonexperimental approach was used to analyze claims data from Georgia Medicaid claims files for all program-eligible persons for each relevant time period (intent-to-treat basis). These included all non-Medicare, noninstitutionalized Medicaid aged-blind-disabled adults older than 18 years of age. Comparisons of health care expenditures and utilization were made between base year (2003–2004) and performance year one (2006–2007), and of the difference between actual expenditures incurred in the performance year vs. projected expenditures based on various cost inflation assumptions. Demographic characteristics and clinical complexity of the population (as measured by the Chronic Illness and Disability Payment System risk score) actually increased from baseline to implementation. Actual expenditures were less than projected expenditures using any relevant medical inflation assumption. Actual expenditures were less than projected expenditures by $9.82 million when using a conservative US general medical inflation rate, by $43.6 million using national Medicaid cost trends, and by $106 million using Georgia Medicaid's own cost projections for the non-dually eligible disabled segment of Medicaid enrollees. Quadratic growth curve modeling also demonstrated a lower rate of increase in total expenditures. The rate of increase in expenditures was lower over the first year of program implementation compared with baseline. Weighted utilization rates were also lower in high-cost categories, such as inpatient days, despite increases in the risk profile of the population. Varying levels of cost avoidance could be inferred from differences between actual and projected expenditures using each of the health-related inflation assumptions. (Population Health Management 2011;14:215–222) PMID:21506728

76 FR 31329 - EPA Radiogenic Cancer Risk Models and Projections for the U.S. Population (Blue Book)

Federal Register 2010, 2011, 2012, 2013, 2014

2011-05-31

... epidemiological study of Japanese atomic bomb survivors, who received an essentially instantaneously delivered... than for the Japanese A- bomb survivors. Such differences may be due to genetic or environmental... both the A-bomb survivors and medically irradiated cohorts. While studies on populations exposed...

Identifying Water Insecurity Hotspots in the Lake Victoria Basin of Eastern Africa

NASA Astrophysics Data System (ADS)

Pricope, N. G.; Shukla, S.; Linard, C.; Gaughan, A.

2014-12-01

The Lake Victoria Basin (LVB), one of Africa's most populated transboundary watersheds and home to more than 30 million inhabitants, is increasingly challenged by both water quality problems and water quantity shortages against a backdrop of climate variability and change; and other environmental challenges. As a result of pollution, droughts, more erratic rainfall, heightened demand for water for both consumption and agricultural needs as well as differences in water allocation among the riverine countries of Uganda, Tanzania, Kenya, Rwanda and Burundi, many parts of this region are already experiencing water scarcity on a recurrent basis. Furthermore, given projected annual population growth rates of 2.5 to 3.5% for the next 20 years, water shortages are likely to be exacerbated in the future. Analyzing historical changes in the water resources of this region is hence important to identify "hot spots" that might be most sensitive to future changes in climate and demography. In this presentation, we report the findings of a comprehensive analysis performed to (i) examine changes in water resources of LVB in recent decades and (ii) identify overlap between regions of significant changes in water resources with land cover changes and high population centers that are also projected to grow the fastest over the coming decades. We first utilize several satellite, stations and model(s) based climatic and hydrologic datasets to assess changes in water resources in this region. We then use a quality-controlled Moderate Resolution Imaging Spectroradiometer (MODIS) land cover product to identify areas of significant land cover changes. Simultaneously we use projections of gridded population density based on differential growth rates for rural and urban population to estimate fastest projected human population growth for 2030 and 2050 relative to 2010 data. Using the outcomes of these change analysis we identify water insecurity hotspots in the LVB.

Population growth rates: issues and an application.

PubMed Central

Godfray, H Charles J; Rees, Mark

2002-01-01

Current issues in population dynamics are discussed in the context of The Royal Society Discussion Meeting 'Population growth rate: determining factors and role in population regulation'. In particular, different views on the centrality of population growth rates to the study of population dynamics and the role of experiments and theory are explored. Major themes emerging include the role of modern statistical techniques in bringing together experimental and theoretical studies, the importance of long-term experimentation and the need for ecology to have model systems, and the value of population growth rate as a means of understanding and predicting population change. The last point is illustrated by the application of a recently introduced technique, integral projection modelling, to study the population growth rate of a monocarpic perennial plant, its elasticities to different life-history components and the evolution of an evolutionarily stable strategy size at flowering. PMID:12396521

[Integration of demographic variables into development plans in the Sahel].

PubMed

Wane, H R

1992-07-01

A founding principle of the Program of Action of N'Djamena is the interdependence of population and development and the need for development strategies to take demographic factors into account. The concept of integration of population variables into development has evolved since its introduction in the 1974 World Population Plan of Action from a simple description of population size, growth rates, and distribution to a stress on harmonizing population policies and development policies with macroeconomic variables. The essence of the concept is the consideration given by development policies and programs to the interrelations between population, resources, the environment, and development factors. Population variables and goals should ideally be treated as endogenous variables in development planning, but in practice the extreme complexity of such a systematic approach limits its ability to be made operational. Usually the most crucial problems only are included. Integrated planning is composed of explicit or implicit population policies intended to influence demographic variables and of socioeconomic policies intended to adapt to demographic change. In the Sahel, only Senegal, Burkina Faso, and Mali have formal population policies, but around 1980 several countries of the region began to show interest in influencing demographic variables as they did economic variables. Fundamental principles for developing an integration strategy can be applied regardless or whether the plan is based on projections, analysis of interaction of a demographic variable with factors specific to a sector, or a monosectorial or multisectorial demoeconomic planning model. Demographic data is used more frequently in diagnosing problems than in developing projections or formulating objectives. The level of disaggregation of demographic projections and estimates tends to be low, despite the great potential utility of demographic projections in planning. Demographic projections can be useful in analyses of the extent of changes and the implications of alternative scenarios of development planning. The most frequently used demographic variables in development planning have been spatial distribution of the population and mortality. An examination of past development plans in Mali relating to population and nutrition and population and health reveals several inconsistencies between stated goals and strategies intended to achieve them. The incoherence can be explained in part by the absence of a coherent national population policy, the failure to translate the population policy into programs that take into account reciprocal effects of demographic trends and economic perspectives and their social effects, and the absence of disaggregated population projections. An example from Senegal demonstrates the constraints imposed by structural adjustment programs on the entire planning process.

Characterizing the impact of projected changes in climate and ...

EPA Pesticide Factsheets

The impact of climate change on human and environmental health is of critical concern. Population exposures to air pollutants both indoors and outdoors are influenced by a wide range of air quality, meteorological, behavioral, and housing-related factors, many of which are also impacted by climate change. An integrated methodology for modeling changes in human exposures to tropospheric ozone (O3) owing to potential future changes in climate and demographics was implemented by linking existing modeling tools for climate, weather, air quality, population distribution, and human exposure. Human exposure results from the Air Pollutants Exposure Model (APEX) for 12 US cities show differences in daily maximum 8-h (DM8H) exposure patterns and levels by sex, age, and city for all scenarios. When climate is held constant and population demographics are varied, minimal difference in O3 exposures is predicted even with the most extreme demographic change scenario. In contrast, when population is held constant, we see evidence of substantial changes in O3 exposure for the most extreme change in climate. Similarly, we see increases in the percentage of the population in each city with at least one O3 exposure exceedance above 60 p.p.b and 70 p.p.b thresholds for future changes in climate. For these climate and population scenarios, the impact of projected changes in climate and air quality on human exposure to O3 are much larger than the impacts of changing demographics.

Vulnerable Population Challenges in the Transformation of Cancer Care.

PubMed

Meneses, Karen; Landier, Wendy; Dionne-Odom, J Nicholas

2016-05-01

To consider current trends and future strategies that will bring about change in cancer care delivery for vulnerable populations. Institute of Medicine reports, literature review, clinical practice observations and experiences. Vulnerable populations are older adults, both minorities and the underserved, children, and individuals at end of life. These groups pose unique challenges that require health system changes and innovative nursing models to assure access to patient-centered care in the future. In the future, attention to the needs of vulnerable populations, the growing aging cancer population and the improved outcomes in the pediatric and adolescent cancer population will all require new nursing services and models of care. System changes where nursing roles are critical to support the transition to earlier palliative care are projected. Copyright © 2016 Elsevier Inc. All rights reserved.

ESP v2.0: Enhanced method for exploring emission impacts of future scenarios in the United States – addressing spatial allocation

EPA Science Inventory

The Emission Scenario Projection (ESP) method produces future-year air pollutant emissions for mesoscale air quality modeling applications. We present ESP v2.0, which expands upon ESP v1.0 by spatially allocating future-year emissions to account for projected population and land ...

Inland Waters Night Lighting Configurations: A Navigation Rules Course for Coast Guard Auxiliarists.

ERIC Educational Resources Information Center

Griffiths, Gregory Peter

A project developed a training program to teach boaters to recognize and interpret properly the lights of other vessels in nighttime or other reduced visibility conditions in the inland waters of the United States. The project followed the Instructional Systems Design model in the development of the course. The target population were members of…

Development and application of a density dependent matrix ...

EPA Pesticide Factsheets

Ranging along the Atlantic coast from US Florida to the Maritime Provinces of Canada, the Atlantic killifish (Fundulus heteroclitus) is an important and well-studied model organism for understanding the effects of pollutants and other stressors in estuarine and marine ecosystems. Matrix population models are useful tools for ecological risk assessment because they integrate effects across the life cycle, provide a linkage between endpoints observed in the individual and ecological risk to the population as a whole, and project outcomes for many generations in the future. We developed a density dependent matrix population model for Atlantic killifish by modifying a model developed for fathead minnow (Pimephales promelas) that has proved to be extremely useful, e.g. to incorporate data from laboratory studies and project effects of endocrine disrupting chemicals. We developed a size-structured model (as opposed to one that is based upon developmental stages or age class structure) so that we could readily incorporate output from a Dynamic Energy Budget (DEB) model, currently under development. Due to a lack of sufficient data to accurately define killifish responses to density dependence, we tested a number of scenarios realistic for other fish species in order to demonstrate the outcome of including this ecologically important factor. We applied the model using published data for killifish exposed to dioxin-like compounds, and compared our results to those using

Model suggests potential for Porites coral population recovery after removal of anthropogenic disturbance (Luhuitou, Hainan, South China Sea).

PubMed

Zhao, Meixia; Riegl, Bernhard; Yu, Kefu; Shi, Qi; Zhang, Qiaomin; Liu, Guohui; Yang, Hongqiang; Yan, Hongqiang

2016-09-13

Population models are important for resource management and can inform about potential trajectories useful for planning purposes, even with incomplete monitoring data. From size frequency data on Luhuitou fringing reef, Hainan, South China Sea, a matrix population model of massive corals (Porites lutea) was developed and trajectories over 100 years under no disturbance and random disturbances were projected. The model reflects a largely open population of Porites lutea, with low local recruitment and preponderance of imported recruitment. Under no further disturbance, the population of Porites lutea will grow and its size structure will change from predominance of small size classes to large size classes. Therewith, total Porites cover will increase. Even under random disturbances every 10 to 20 years, the Porites population could remain viable, albeit at lower space cover. The models suggest recovery at Luhuitou following the removal of chronic anthropogenic disturbance. Extending the area of coral reef reserves to protect the open coral community and the path of connectivity is advisable and imperative for the conservation of Hainan's coral reefs.

Model suggests potential for Porites coral population recovery after removal of anthropogenic disturbance (Luhuitou, Hainan, South China Sea)

PubMed Central

Zhao, Meixia; Riegl, Bernhard; Yu, Kefu; Shi, Qi; Zhang, Qiaomin; Liu, Guohui; Yang, Hongqiang; Yan, Hongqiang

2016-01-01

Population models are important for resource management and can inform about potential trajectories useful for planning purposes, even with incomplete monitoring data. From size frequency data on Luhuitou fringing reef, Hainan, South China Sea, a matrix population model of massive corals (Porites lutea) was developed and trajectories over 100 years under no disturbance and random disturbances were projected. The model reflects a largely open population of Porites lutea, with low local recruitment and preponderance of imported recruitment. Under no further disturbance, the population of Porites lutea will grow and its size structure will change from predominance of small size classes to large size classes. Therewith, total Porites cover will increase. Even under random disturbances every 10 to 20 years, the Porites population could remain viable, albeit at lower space cover. The models suggest recovery at Luhuitou following the removal of chronic anthropogenic disturbance. Extending the area of coral reef reserves to protect the open coral community and the path of connectivity is advisable and imperative for the conservation of Hainan’s coral reefs. PMID:27622504

Recent progress in the theoretical modelling of Cepheids and RR Lyrae stars

NASA Astrophysics Data System (ADS)

Marconi, Marcella

2017-09-01

Cepheids and RR Lyrae are among the most important primary distance indicators to calibrate the extragalactic distance ladder and excellent stellar population tracers, for Population I and Population II, respectively. In this paper I first mention some recent theoretical studies of Cepheids and RR Lyrae obtained with different theoretical tools. Then I focus the attention on new results based on nonlinear convective pulsation models in the context of some international projects, including VMC@VISTA and the Gaia collaboration. The open problems for both Cepheids and RR Lyrae are briefly discussed together with some challenging future application.

Adaptive and plastic responses of Quercus petraea populations to climate across Europe.

PubMed

Sáenz-Romero, Cuauhtémoc; Lamy, Jean-Baptiste; Ducousso, Alexis; Musch, Brigitte; Ehrenmann, François; Delzon, Sylvain; Cavers, Stephen; Chałupka, Władysław; Dağdaş, Said; Hansen, Jon Kehlet; Lee, Steve J; Liesebach, Mirko; Rau, Hans-Martin; Psomas, Achilleas; Schneck, Volker; Steiner, Wilfried; Zimmermann, Niklaus E; Kremer, Antoine

2017-07-01

How temperate forests will respond to climate change is uncertain; projections range from severe decline to increased growth. We conducted field tests of sessile oak (Quercus petraea), a widespread keystone European forest tree species, including more than 150 000 trees sourced from 116 geographically diverse populations. The tests were planted on 23 field sites in six European countries, in order to expose them to a wide range of climates, including sites reflecting future warmer and drier climates. By assessing tree height and survival, our objectives were twofold: (i) to identify the source of differential population responses to climate (genetic differentiation due to past divergent climatic selection vs. plastic responses to ongoing climate change) and (ii) to explore which climatic variables (temperature or precipitation) trigger the population responses. Tree growth and survival were modeled for contemporary climate and then projected using data from four regional climate models for years 2071-2100, using two greenhouse gas concentration trajectory scenarios each. Overall, results indicated a moderate response of tree height and survival to climate variation, with changes in dryness (either annual or during the growing season) explaining the major part of the response. While, on average, populations exhibited local adaptation, there was significant clinal population differentiation for height growth with winter temperature at the site of origin. The most moderate climate model (HIRHAM5-EC; rcp4.5) predicted minor decreases in height and survival, while the most extreme model (CCLM4-GEM2-ES; rcp8.5) predicted large decreases in survival and growth for southern and southeastern edge populations (Hungary and Turkey). Other nonmarginal populations with continental climates were predicted to be severely and negatively affected (Bercé, France), while populations at the contemporary northern limit (colder and humid maritime regions; Denmark and Norway) will probably not show large changes in growth and survival in response to climate change. © 2017 John Wiley & Sons Ltd.

Idea Bank.

ERIC Educational Resources Information Center

Bisbee, Gregory D.; Fritz, Jane K.; Zurenda, Deb

1997-01-01

Presents three science activities: (1) Pizza Quadrants, a tool for estimating population size; (2) Ion Models, to assist students in understanding how to balance equations; and (3) Endangered Species Project, an interdisciplinary unit. (DDR)

Mixing times towards demographic equilibrium in insect populations with temperature variable age structures.

PubMed

Damos, Petros

2015-08-01

In this study, we use entropy related mixing rate modules to measure the effects of temperature on insect population stability and demographic breakdown. The uncertainty in the age of the mother of a randomly chosen newborn, and how it is moved after a finite act of time steps, is modeled using a stochastic transformation of the Leslie matrix. Age classes are represented as a cycle graph and its transitions towards the stable age distribution are brought forth as an exact Markov chain. The dynamics of divergence, from a non equilibrium state towards equilibrium, are evaluated using the Kolmogorov-Sinai entropy. Moreover, Kullback-Leibler distance is applied as information-theoretic measure to estimate exact mixing times of age transitions probabilities towards equilibrium. Using empirically data, we show that on the initial conditions and simulated projection's trough time, that population entropy can effectively be applied to detect demographic variability towards equilibrium under different temperature conditions. Changes in entropy are correlated with the fluctuations of the insect population decay rates (i.e. demographic stability towards equilibrium). Moreover, shorter mixing times are directly linked to lower entropy rates and vice versa. This may be linked to the properties of the insect model system, which in contrast to warm blooded animals has the ability to greatly change its metabolic and demographic rates. Moreover, population entropy and the related distance measures that are applied, provide a means to measure these rates. The current results and model projections provide clear biological evidence why dynamic population entropy may be useful to measure population stability. Copyright © 2015 Elsevier Inc. All rights reserved.

Meteorological limits on the growth and development of screwworm populations

NASA Technical Reports Server (NTRS)

Phinney, D. E.; Arp, G. K.

1978-01-01

A program to evaluate the use of remotely sensed data as an additional tool in existing and projected efforts to eradicate the screwworm began in 1973. Estimating weather conditions by use of remotely sensed data was part of the study. Next, the effect of weather on screwworm populations was modeled. A significant portion of the variation in screwworm population growth and development has been traced to weather-related parameters. This report deals with the salient points of the weather and the screwworm population interaction.

Estimates of Present and Future Flood Risk in the Conterminous United States

NASA Astrophysics Data System (ADS)

Wing, O.; Bates, P. D.; Smith, A.; Sampson, C. C.; Johnson, K.; Fargione, J.; Morefield, P.

2017-12-01

Past attempts to estimate flood risk across the USA either have incomplete coverage, coarse resolution or use overly simplified models of the flooding process. In this paper, we use a new 30m resolution model of the entire conterminous US (CONUS) with realistic flood physics to produce estimates of flood hazard which match to within 90% accuracy the skill of local models built with detailed data. Socio-economic data of commensurate resolution are combined with these flood depths to estimate current and future flood risk. Future population and land-use projections from the US Environmental Protection Agency (USEPA) are employed to indicate how flood risk might change through the 21st Century, while present-day estimates utilize the Federal Emergency Management Agency (FEMA) National Structure Inventory and a USEPA map of population distribution. Our data show that the total CONUS population currently exposed to serious flooding is 2.6 to 3.1 times higher than previous estimates; with nearly 41 million Americans living within the so-called 1 in 100-year (1% annual probability) floodplain, compared to only 13 million according to FEMA flood maps. Moreover, socio-economic change alone leads to significant future increases in flood exposure and risk, even before climate change impacts are accounted for. The share of the population living on the 1 in 100-year floodplain is projected to increase from 13.3% in the present-day to 15.6 - 15.8% in 2050 and 16.4 - 16.8% in 2100. The area of developed land within this floodplain, currently at 150,000 km2, is likely to increase by 37 - 72% in 2100 based on the scenarios selected. 5.5 trillion worth of assets currently lie on the 1% floodplain; we project that by 2100 this number will exceed 10 trillion. With this detailed spatial information on present-day flood risk, federal and state agencies can take appropriate action to mitigate losses. Use of USEPA population and land-use projections mean that particular attention can be paid to floodplains where development is projected. Steps to conserve such areas or ensure adequate defenses are in place could avoid the exposure of trillions of dollars of assets, not to mention the human suffering caused by loss of property and life.

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

NASA Astrophysics Data System (ADS)

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.

Evolution in Cloud Population Statistics of the MJO: From AMIE Field Observations to Global Cloud-Permiting Models

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhang, Chidong

Motivated by the success of the AMIE/DYNAMO field campaign, which collected unprecedented observations of cloud and precipitation from the tropical Indian Ocean in Octber 2011 – March 2012, this project explored how such observations can be applied to assist the development of global cloud-permitting models through evaluating and correcting model biases in cloud statistics. The main accomplishment of this project were made in four categories: generating observational products for model evaluation, using AMIE/DYNAMO observations to validate global model simulations, using AMIE/DYNAMO observations in numerical studies of cloud-permitting models, and providing leadership in the field. Results from this project provide valuablemore » information for building a seamless bridge between DOE ASR program’s component on process level understanding of cloud processes in the tropics and RGCM focus on global variability and regional extremes. In particular, experience gained from this project would be directly applicable to evaluation and improvements of ACME, especially as it transitions to a non-hydrostatic variable resolution model.« less

Recent range expansion of a terrestrial orchid corresponds with climate-driven variation in its population dynamics.

PubMed

van der Meer, Sascha; Jacquemyn, Hans; Carey, Peter D; Jongejans, Eelke

2016-06-01

The population dynamics and distribution limits of plant species are predicted to change as the climate changes. However, it remains unclear to what extent climate variables affect population dynamics, which vital rates are most sensitive to climate change, and whether the same vital rates drive population dynamics in different populations. In this study, we used long-term demographic data from two populations of the terrestrial orchid Himantoglossum hircinum growing at the northern edge of their geographic range to quantify the influence of climate change on demographic vital rates. Integral projection models were constructed to study how climate conditions between 1991 and 2006 affected population dynamics and to assess how projected future climate change will affect the long-term viability of this species. Based on the parameterised vital rate functions and the observed climatic conditions, one of the studied populations had an average population growth rate above 1 (λ = 1.04), while the other was declining at ca. 3 % year(-1) (λ = 0.97). Variation in temperature and precipitation mainly affected population growth through their effect on survival and fecundity. Based on UK Climate Projection 2009 estimates of future climate conditions for three greenhouse gas emission scenarios, population growth rates are expected to increase in one of the studied populations. Overall, our results indicate that the observed changes in climatic conditions appeared to be beneficial to the long-term survival of the species in the UK and suggest that they may have been the driving force behind the current range expansion of H. hircinum in England.

Oceanography and life history predict contrasting genetic population structure in two Antarctic fish species

PubMed Central

Young, Emma F; Belchier, Mark; Hauser, Lorenz; Horsburgh, Gavin J; Meredith, Michael P; Murphy, Eugene J; Pascoal, Sonia; Rock, Jennifer; Tysklind, Niklas; Carvalho, Gary R

2015-01-01

Understanding the key drivers of population connectivity in the marine environment is essential for the effective management of natural resources. Although several different approaches to evaluating connectivity have been used, they are rarely integrated quantitatively. Here, we use a ‘seascape genetics’ approach, by combining oceanographic modelling and microsatellite analyses, to understand the dominant influences on the population genetic structure of two Antarctic fishes with contrasting life histories, Champsocephalus gunnari and Notothenia rossii. The close accord between the model projections and empirical genetic structure demonstrated that passive dispersal during the planktonic early life stages is the dominant influence on patterns and extent of genetic structuring in both species. The shorter planktonic phase of C. gunnari restricts direct transport of larvae between distant populations, leading to stronger regional differentiation. By contrast, geographic distance did not affect differentiation in N. rossii, whose longer larval period promotes long-distance dispersal. Interannual variability in oceanographic flows strongly influenced the projected genetic structure, suggesting that shifts in circulation patterns due to climate change are likely to impact future genetic connectivity and opportunities for local adaptation, resilience and recovery from perturbations. Further development of realistic climate models is required to fully assess such potential impacts. PMID:26029262

Future cardiovascular disease in China: Markov model and risk factor scenario projections from the Coronary Heart Disease Policy Model-China

PubMed Central

Moran, Andrew; Gu, Dongfeng; Zhao, Dong; Coxson, Pamela; Wang, Y. Claire; Chen, Chung-Shiuan; Liu, Jing; Cheng, Jun; Bibbins-Domingo, Kirsten; Shen, Yu-Ming; He, Jiang; Goldman, Lee

2010-01-01

Background The relative effects of individual and combined risk factor trends on future cardiovascular disease in China have not been quantified in detail. Methods and Results Future risk factor trends in China were projected based on prior trends. Cardiovascular disease (coronary heart disease and stroke) in adults ages 35 to 84 years was projected from 2010 to 2030 using the Coronary Heart Disease Policy Model–China, a Markov computer simulation model. With risk factor levels held constant, projected annual cardiovascular events increased by >50% between 2010 and 2030 based on population aging and growth alone. Projected trends in blood pressure, total cholesterol, diabetes (increases), and active smoking (decline) would increase annual cardiovascular disease events by an additional 23%, an increase of approximately 21.3 million cardiovascular events and 7.7 million cardiovascular deaths over 2010 to 2030. Aggressively reducing active smoking in Chinese men to 20% prevalence in 2020 and 10% prevalence in 2030 or reducing mean systolic blood pressure by 3.8 mm Hg in men and women would counteract adverse trends in other risk factors by preventing cardiovascular events and 2.9 to 5.7 million total deaths over 2 decades. Conclusions Aging and population growth will increase cardiovascular disease by more than a half over the coming 20 years, and projected unfavorable trends in blood pressure, total cholesterol, diabetes, and body mass index may accelerate the epidemic. National policy aimed at controlling blood pressure, smoking, and other risk factors would counteract the expected future cardiovascular disease epidemic in China. PMID:20442213

Forecasting climate change impacts on plant populations over large spatial extents

DOE PAGES

Tredennick, Andrew T.; Hooten, Mevin B.; Aldridge, Cameron L.; ...

2016-10-24

Plant population models are powerful tools for predicting climate change impacts in one location, but are difficult to apply at landscape scales. Here, we overcome this limitation by taking advantage of two recent advances: remotely sensed, species-specific estimates of plant cover and statistical models developed for spatiotemporal dynamics of animal populations. Using computationally efficient model reparameterizations, we fit a spatiotemporal population model to a 28-year time series of sagebrush (Artemisia spp.) percent cover over a 2.5 × 5 km landscape in southwestern Wyoming while formally accounting for spatial autocorrelation. We include interannual variation in precipitation and temperature as covariates inmore » the model to investigate how climate affects the cover of sagebrush. We then use the model to forecast the future abundance of sagebrush at the landscape scale under projected climate change, generating spatially explicit estimates of sagebrush population trajectories that have, until now, been impossible to produce at this scale. Our broadscale and long-term predictions are rooted in small-scale and short-term population dynamics and provide an alternative to predictions offered by species distribution models that do not include population dynamics. Finally, our approach, which combines several existing techniques in a novel way, demonstrates the use of remote sensing data to model population responses to environmental change that play out at spatial scales far greater than the traditional field study plot.« less

Forecasting climate change impacts on plant populations over large spatial extents

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tredennick, Andrew T.; Hooten, Mevin B.; Aldridge, Cameron L.

Plant population models are powerful tools for predicting climate change impacts in one location, but are difficult to apply at landscape scales. Here, we overcome this limitation by taking advantage of two recent advances: remotely sensed, species-specific estimates of plant cover and statistical models developed for spatiotemporal dynamics of animal populations. Using computationally efficient model reparameterizations, we fit a spatiotemporal population model to a 28-year time series of sagebrush (Artemisia spp.) percent cover over a 2.5 × 5 km landscape in southwestern Wyoming while formally accounting for spatial autocorrelation. We include interannual variation in precipitation and temperature as covariates inmore » the model to investigate how climate affects the cover of sagebrush. We then use the model to forecast the future abundance of sagebrush at the landscape scale under projected climate change, generating spatially explicit estimates of sagebrush population trajectories that have, until now, been impossible to produce at this scale. Our broadscale and long-term predictions are rooted in small-scale and short-term population dynamics and provide an alternative to predictions offered by species distribution models that do not include population dynamics. Finally, our approach, which combines several existing techniques in a novel way, demonstrates the use of remote sensing data to model population responses to environmental change that play out at spatial scales far greater than the traditional field study plot.« less

Forecasting climate change impacts on plant populations over large spatial extents

USGS Publications Warehouse

Tredennick, Andrew T.; Hooten, Mevin B.; Aldridge, Cameron L.; Homer, Collin G.; Kleinhesselink, Andrew R.; Adler, Peter B.

2016-01-01

Plant population models are powerful tools for predicting climate change impacts in one location, but are difficult to apply at landscape scales. We overcome this limitation by taking advantage of two recent advances: remotely sensed, species-specific estimates of plant cover and statistical models developed for spatiotemporal dynamics of animal populations. Using computationally efficient model reparameterizations, we fit a spatiotemporal population model to a 28-year time series of sagebrush (Artemisia spp.) percent cover over a 2.5 × 5 km landscape in southwestern Wyoming while formally accounting for spatial autocorrelation. We include interannual variation in precipitation and temperature as covariates in the model to investigate how climate affects the cover of sagebrush. We then use the model to forecast the future abundance of sagebrush at the landscape scale under projected climate change, generating spatially explicit estimates of sagebrush population trajectories that have, until now, been impossible to produce at this scale. Our broadscale and long-term predictions are rooted in small-scale and short-term population dynamics and provide an alternative to predictions offered by species distribution models that do not include population dynamics. Our approach, which combines several existing techniques in a novel way, demonstrates the use of remote sensing data to model population responses to environmental change that play out at spatial scales far greater than the traditional field study plot.

Strategies for reforestation under uncertain future climates: guidelines for Alberta, Canada.

PubMed

Gray, Laura K; Hamann, Andreas

2011-01-01

Commercial forestry programs normally use locally collected seed for reforestation under the assumption that tree populations are optimally adapted to local environments. However, in western Canada this assumption is no longer valid because of climate trends that have occurred over the last several decades. The objective of this study is to show how we can arrive at reforestation recommendations with alternative species and genotypes that are viable under a majority of climate change scenarios. In a case study for commercially important tree species of Alberta, we use an ecosystem-based bioclimate envelope modeling approach for western North America to project habitat for locally adapted populations of tree species using multi-model climate projections for the 2020s, 2050s and 2080s. We find that genotypes of species that are adapted to drier climatic conditions will be the preferred planting stock over much of the boreal forest that is commercially managed. Interestingly, no alternative species that are currently not present in Alberta can be recommended with any confidence. Finally, we observe large uncertainties in projections of suitable habitat that make reforestation planning beyond the 2050s difficult for most species. More than 50,000 hectares of forests are commercially planted every year in Alberta. Choosing alternative planting stock, suitable for expected future climates, could therefore offer an effective climate change adaptation strategy at little additional cost. Habitat projections for locally adapted tree populations under observed climate change conform well to projections for the 2020s, which suggests that it is a safe strategy to change current reforestation practices and adapt to new climatic realities through assisted migration prescriptions.

Integrating Temperature-Dependent Life Table Data into a Matrix Projection Model for Drosophila suzukii Population Estimation

PubMed Central

Wiman, Nik G.; Walton, Vaughn M.; Dalton, Daniel T.; Anfora, Gianfranco; Burrack, Hannah J.; Chiu, Joanna C.; Daane, Kent M.; Grassi, Alberto; Miller, Betsey; Tochen, Samantha; Wang, Xingeng; Ioriatti, Claudio

2014-01-01

Temperature-dependent fecundity and survival data was integrated into a matrix population model to describe relative Drosophila suzukii Matsumura (Diptera: Drosophilidae) population increase and age structure based on environmental conditions. This novel modification of the classic Leslie matrix population model is presented as a way to examine how insect populations interact with the environment, and has application as a predictor of population density. For D. suzukii, we examined model implications for pest pressure on crops. As case studies, we examined model predictions in three small fruit production regions in the United States (US) and one in Italy. These production regions have distinctly different climates. In general, patterns of adult D. suzukii trap activity broadly mimicked seasonal population levels predicted by the model using only temperature data. Age structure of estimated populations suggest that trap and fruit infestation data are of limited value and are insufficient for model validation. Thus, we suggest alternative experiments for validation. The model is advantageous in that it provides stage-specific population estimation, which can potentially guide management strategies and provide unique opportunities to simulate stage-specific management effects such as insecticide applications or the effect of biological control on a specific life-stage. The two factors that drive initiation of the model are suitable temperatures (biofix) and availability of a suitable host medium (fruit). Although there are many factors affecting population dynamics of D. suzukii in the field, temperature-dependent survival and reproduction are believed to be the main drivers for D. suzukii populations. PMID:25192013

The influence of coarse-scale environmental features on current and predicted future distributions of narrow-range endemic crayfish populations

USGS Publications Warehouse

Dyer, Joseph J.; Brewer, Shannon K.; Worthington, Thomas A.; Bergey, Elizabeth A.

2013-01-01

1.A major limitation to effective management of narrow-range crayfish populations is the paucity of information on the spatial distribution of crayfish species and a general understanding of the interacting environmental variables that drive current and future potential distributional patterns. 2.Maximum Entropy Species Distribution Modeling Software (MaxEnt) was used to predict the current and future potential distributions of four endemic crayfish species in the Ouachita Mountains. Current distributions were modelled using climate, geology, soils, land use, landform and flow variables thought to be important to lotic crayfish. Potential changes in the distribution were forecast by using models trained on current conditions and projecting onto the landscape predicted under climate-change scenarios. 3.The modelled distribution of the four species closely resembled the perceived distribution of each species but also predicted populations in streams and catchments where they had not previously been collected. Soils, elevation and winter precipitation and temperature most strongly related to current distributions and represented 6587% of the predictive power of the models. Model accuracy was high for all models, and model predictions of new populations were verified through additional field sampling. 4.Current models created using two spatial resolutions (1 and 4.5km2) showed that fine-resolution data more accurately represented current distributions. For three of the four species, the 1-km2 resolution models resulted in more conservative predictions. However, the modelled distributional extent of Orconectes leptogonopodus was similar regardless of data resolution. Field validations indicated 1-km2 resolution models were more accurate than 4.5-km2 resolution models. 5.Future projected (4.5-km2 resolution models) model distributions indicated three of the four endemic species would have truncated ranges with low occurrence probabilities under the low-emission scenario, whereas two of four species would be severely restricted in range under moderatehigh emissions. Discrepancies in the two emission scenarios probably relate to the exclusion of behavioural adaptations from species-distribution models. 6.These model predictions illustrate possible impacts of climate change on narrow-range endemic crayfish populations. The predictions do not account for biotic interactions, migration, local habitat conditions or species adaptation. However, we identified the constraining landscape features acting on these populations that provide a framework for addressing habitat needs at a fine scale and developing targeted and systematic monitoring programmes.

Eastgate Geothermal Borehole Project: Predicting Fracture Geometry at Depth

NASA Astrophysics Data System (ADS)

Beattie, Stewart; Shipton, Zoe K.; Johnson, Gareth; Younger, Paul L.

2013-04-01

In 2004 an exploratory borehole at the Eastgate Geothermal Project encountered part of a vein system within the Weardale granite. At 995m depth brine was at a temperature of around 46°C. The geothermal source is likely related to the Slitt vein system that cuts through c.270m of carboniferous sedimentary strata overlying the Weardale granite pluton. The economic success of the Eastgate geothermal project is dependent on exploiting this vein system in an otherwise low permeability and low geothermal gradient setting. The Slitt vein system has been extensively mined. Mining records show the attitude of the vein through the sedimentary strata, however, the trajectory and magnitude of the vein within the pluton itself is unknown. Using mine records, geological maps and published literature, models of the vein system up to the depth of the pluton were created. To extend this model into the pluton itself requires some knowledge regarding the geometry and evolution of the pluton and subsequently properties of vein systems and other fracture populations at depth. The properties of fracture and vein populations within the granite will depend on forming processes including; cooling and contraction of the pluton, deformation of host rocks during pluton emplacement, and post emplacement deformation. Using published literature and gravity data a 3D model of the geometry of the pluton was constructed. Shape analysis of the pluton allows an estimation of the orientation of fractures within the pluton. Further modelling of the structural evolution of the pluton will enable kinematic or geomechanical strain associated with the structural evolution to be captured and subsequently used as a proxy for modelling both intensity and orientation of fracturing within the pluton. The successful prediction of areas of high fracture intensity and thus increased permeability is critical to the development of potential geothermal resources in low geothermal gradient and low permeability settings. This is also important in EGS settings where stimulation will often re-activate existing fracture networks. The development at the Eastgate Geothermal Borehole project provides an opportunity to model fracture and vein populations within an intrusive body and validate those model predictions with production data from the site.

Species distributions models in wildlife planning: agricultural policy and wildlife management in the great plains

USGS Publications Warehouse

Fontaine, Joseph J.; Jorgensen, Christopher; Stuber, Erica F.; Gruber, Lutz F.; Bishop, Andrew A.; Lusk, Jeffrey J.; Zach, Eric S.; Decker, Karie L.

2017-01-01

We know economic and social policy has implications for ecosystems at large, but the consequences for a given geographic area or specific wildlife population are more difficult to conceptualize and communicate. Species distribution models, which extrapolate species-habitat relationships across ecological scales, are capable of predicting population changes in distribution and abundance in response to management and policy, and thus, are an ideal means for facilitating proactive management within a larger policy framework. To illustrate the capabilities of species distribution modeling in scenario planning for wildlife populations, we projected an existing distribution model for ring-necked pheasants (Phasianus colchicus) onto a series of alternative future landscape scenarios for Nebraska, USA. Based on our scenarios, we qualitatively and quantitatively estimated the effects of agricultural policy decisions on pheasant populations across Nebraska, in specific management regions, and at wildlife management areas. 

Placing invasive species management in a spatiotemporal context.

PubMed

Baker, Christopher M; Bode, Michael

2016-04-01

Invasive species are a worldwide issue, both ecologically and economically. A large body of work focuses on various aspects of invasive species control, including how to allocate control efforts to eradicate an invasive population as cost effectively as possible: There are a diverse range of invasive species management problems, and past mathematical analyses generally focus on isolated examples, making it hard to identify and understand parallels between the different contexts. In this study, we use a single spatiotemporal model to tackle the problem of allocating control effort for invasive species when suppressing an island invasive species, and for long-term spatial suppression projects. Using feral cat suppression as an illustrative example, we identify the optimal resource allocation for island and mainland suppression projects. Our results demonstrate how using a single model to solve different problems reveals similar characteristics of the solutions in different scenarios. As well as illustrating the insights offered by linking problems through a spatiotemporal model, we also derive novel and practically applicable results for our case studies. For temporal suppression projects on islands, we find that lengthy projects are more cost effective and that rapid control projects are only economically cost effective when population growth rates are high or diminishing returns on control effort are low. When suppressing invasive species around conservation assets (e.g., national parks or exclusion fences), we find that the size of buffer zones should depend on the ratio of the species growth and spread rate.

Ecological modelling and toxicity data coupled to assess population recovery of marine amphipod Gammarus locusta: Application to disturbance by chronic exposure to aniline.

PubMed

de los Santos, Carmen B; Neuparth, Teresa; Torres, Tiago; Martins, Irene; Cunha, Isabel; Sheahan, Dave; McGowan, Tom; Santos, Miguel M

2015-06-01

A population agent-based model of marine amphipod Gammarus locusta was designed and implemented as a basis for ecological risk assessment of chemical pollutants impairing life-history traits at the individual level. We further used the model to assess the toxic effects of aniline (a priority hazardous and noxious substance, HNS) on amphipod populations using empirically-built dose-response functions derived from a chronic bioassay that we previously performed with this species. We observed a significant toxicant-induced mortality and adverse effects in reproductive performance (reduction of newborn production) in G. locusta at the individual level. Coupling the population model with the toxicological data from the chronic bioassay allowed the projection of the ecological costs associated with exposure to aniline that might occur in wild populations. Model simulations with different scenarios indicated that even low level prolonged exposure to the HNS aniline can have significant long-term impacts on G. locusta population abundance, until the impacted population returns to undisturbed levels. This approach may be a useful complement in ecotoxicological studies of chemical pollution to transfer individual-collected data to ecological-relevant levels. Copyright © 2015 Elsevier B.V. All rights reserved.

Tools for assessing climate impacts on fish and wildlife

Treesearch

Chad B. Wilsey; Joshua J. Lawler; Edwin P. Maurer; Donald McKenzie; Patricia A. Townsend; Richard Gwozdz; James A. Freund; Keala Hagmann; Karen M. Hutten

2013-01-01

Climate change is already affecting many fish and wildlife populations. Managing these populations requires an understanding of the nature, magnitude, and distribution of current and future climate impacts. Scientists and managers have at their disposal a wide array of models for projecting climate impacts that can be used to build such an understanding. Here, we...

The costs of diabetes among Australians aged 45–64 years from 2015 to 2030: projections of lost productive life years (PLYs), lost personal income, lost taxation revenue, extra welfare payments and lost gross domestic product from Health&WealthMOD2030

PubMed Central

Schofield, Deborah; Shrestha, Rupendra N; Cunich, Michelle M; Veerman, Lennert; Tanton, Robert; Kelly, Simon J

2017-01-01

Objectives To project the number of people aged 45–64 years with lost productive life years (PLYs) due to diabetes and related costs (lost income, extra welfare payments, lost taxation revenue); and lost gross domestic product (GDP) attributable to diabetes in Australia from 2015 to 2030. Design A simulation study of how the number of people aged 45–64 years with diabetes increases over time (based on population growth and disease trend data) and the economic losses incurred by individuals and the government. Cross-sectional outputs of a microsimulation model (Health&WealthMOD2030) which used the Australian Bureau of Statistics’ Survey of Disability, Ageing and Carers 2003 and 2009 as a base population and integrated outputs from two microsimulation models (Static Incomes Model and Australian Population and Policy Simulation Model), Treasury's population and labour force projections, and chronic disease trends data. Setting Australian population aged 45–64 years in 2015, 2020, 2025 and 2030. Outcome measures Lost PLYs, lost income, extra welfare payments, lost taxation revenue, lost GDP. Results 18 100 people are out of the labour force due to diabetes in 2015, increasing to 21 400 in 2030 (18% increase). National costs consisted of a loss of $A467 million in annual income in 2015, increasing to $A807 million in 2030 (73% increase). For the government, extra annual welfare payments increased from $A311 million in 2015 to $A350 million in 2030 (13% increase); and lost annual taxation revenue increased from $A102 million in 2015 to $A166 million in 2030 (63% increase). A loss of $A2.1 billion in GDP was projected for 2015, increasing to $A2.9 billion in 2030 attributable to diabetes through its impact on PLYs. Conclusions Individuals incur significant costs of diabetes through lost PLYs and lost income in addition to disease burden through human suffering and healthcare costs. The government incurs extra welfare payments, lost taxation revenue and lost GDP, along with direct healthcare costs. PMID:28069621

The costs of diabetes among Australians aged 45-64 years from 2015 to 2030: projections of lost productive life years (PLYs), lost personal income, lost taxation revenue, extra welfare payments and lost gross domestic product from Health&WealthMOD2030.

PubMed

Schofield, Deborah; Shrestha, Rupendra N; Cunich, Michelle M; Passey, Megan E; Veerman, Lennert; Tanton, Robert; Kelly, Simon J

2017-01-09

To project the number of people aged 45-64 years with lost productive life years (PLYs) due to diabetes and related costs (lost income, extra welfare payments, lost taxation revenue); and lost gross domestic product (GDP) attributable to diabetes in Australia from 2015 to 2030. A simulation study of how the number of people aged 45-64 years with diabetes increases over time (based on population growth and disease trend data) and the economic losses incurred by individuals and the government. Cross-sectional outputs of a microsimulation model (Health&WealthMOD2030) which used the Australian Bureau of Statistics' Survey of Disability, Ageing and Carers 2003 and 2009 as a base population and integrated outputs from two microsimulation models (Static Incomes Model and Australian Population and Policy Simulation Model), Treasury's population and labour force projections, and chronic disease trends data. Australian population aged 45-64 years in 2015, 2020, 2025 and 2030. Lost PLYs, lost income, extra welfare payments, lost taxation revenue, lost GDP. 18 100 people are out of the labour force due to diabetes in 2015, increasing to 21 400 in 2030 (18% increase). National costs consisted of a loss of $A467 million in annual income in 2015, increasing to $A807 million in 2030 (73% increase). For the government, extra annual welfare payments increased from $A311 million in 2015 to $A350 million in 2030 (13% increase); and lost annual taxation revenue increased from $A102 million in 2015 to $A166 million in 2030 (63% increase). A loss of $A2.1 billion in GDP was projected for 2015, increasing to $A2.9 billion in 2030 attributable to diabetes through its impact on PLYs. Individuals incur significant costs of diabetes through lost PLYs and lost income in addition to disease burden through human suffering and healthcare costs. The government incurs extra welfare payments, lost taxation revenue and lost GDP, along with direct healthcare costs. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/.

Building integral projection models: a user's guide.

PubMed

Rees, Mark; Childs, Dylan Z; Ellner, Stephen P

2014-05-01

In order to understand how changes in individual performance (growth, survival or reproduction) influence population dynamics and evolution, ecologists are increasingly using parameterized mathematical models. For continuously structured populations, where some continuous measure of individual state influences growth, survival or reproduction, integral projection models (IPMs) are commonly used. We provide a detailed description of the steps involved in constructing an IPM, explaining how to: (i) translate your study system into an IPM; (ii) implement your IPM; and (iii) diagnose potential problems with your IPM. We emphasize how the study organism's life cycle, and the timing of censuses, together determine the structure of the IPM kernel and important aspects of the statistical analysis used to parameterize an IPM using data on marked individuals. An IPM based on population studies of Soay sheep is used to illustrate the complete process of constructing, implementing and evaluating an IPM fitted to sample data. We then look at very general approaches to parameterizing an IPM, using a wide range of statistical techniques (e.g. maximum likelihood methods, generalized additive models, nonparametric kernel density estimators). Methods for selecting models for parameterizing IPMs are briefly discussed. We conclude with key recommendations and a brief overview of applications that extend the basic model. The online Supporting Information provides commented R code for all our analyses. © 2014 The Authors. Journal of Animal Ecology published by John Wiley & Sons Ltd on behalf of British Ecological Society.

Population Modeling of Modified Risk Tobacco Products Accounting for Smoking Reduction and Gradual Transitions of Relative Risk.

PubMed

Poland, Bill; Teischinger, Florian

2017-11-01

As suggested by the Food and Drug Administration (FDA) Modified Risk Tobacco Product (MRTP) Applications Draft Guidance, we developed a statistical model based on public data to explore the effect on population mortality of an MRTP resulting in reduced conventional cigarette smoking. Many cigarette smokers who try an MRTP persist as dual users while smoking fewer conventional cigarettes per day (CPD). Lower-CPD smokers have lower mortality risk based on large cohort studies. However, with little data on the effect of smoking reduction on mortality, predictive modeling is needed. We generalize prior assumptions of gradual, exponential decay of Excess Risk (ER) of death, relative to never-smokers, after quitting or reducing CPD. The same age-dependent slopes are applied to all transitions, including initiation to conventional cigarettes and to a second product (MRTP). A Monte Carlo simulation model generates random individual product use histories, including CPD, to project cumulative deaths through 2060 in a population with versus without the MRTP. Transitions are modeled to and from dual use, which affects CPD and cigarette quit rates, and to MRTP use only. Results in a hypothetical scenario showed high sensitivity of long-run mortality to CPD reduction levels and moderate sensitivity to ER transition rates. Models to project population effects of an MRTP should account for possible mortality effects of reduced smoking among dual users. In addition, studies should follow dual-user CPD histories and quit rates over long time periods to clarify long-term usage patterns and thereby improve health impact projections. We simulated mortality effects of a hypothetical MRTP accounting for cigarette smoking reduction by smokers who add MRTP use. Data on relative mortality risk versus CPD suggest that this reduction may have a substantial effect on mortality rates, unaccounted for in other models. This effect is weighed with additional hypothetical effects in an example. © The Author 2017. Published by Oxford University Press on behalf of the Society for Research on Nicotine and Tobacco. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

BIRTH AND DEATH PROJECTIONS USED IN PRESENT STUDENT-TEACHER POPULATION GROWTH MODELS.

ERIC Educational Resources Information Center

OKADA, TETSUO

A BRIEF DESCRIPTION OF THE METHODOLOGY USED IN DYNAMOD II TO PROJECT BIRTHS AND DEATHS IS PRESENTED. THE COMPUTATION OF DEATH RATES FOLLOWED THE METHOD USED BY THE DEPARTMENT OF HEALTH, EDUCATION AND WELFARE, MORTALITY DIVISION--DEATH RATE FOR AGE INTERVAL I THROUGH J EQUALS SUMMATION OF NUMBER OF DEATHS AT AGES I THROUGH J/SUMMATION OF POPULATION…

School Resegregation: Residential and School Process Study. A Collaborative Leadership Planning/Training Project, Third Year: 1978-79. Final Report.

ERIC Educational Resources Information Center

Williams, Georgia

This report summarizes the work undertaken by the Berkeley Unified School District's (BUSD) project to define a collaborative leadership planning/training model to combat school resegregation. In 1972, four years after full desegregation, the BUSD experienced a marked shift in the school population and its distribution. In 1976, the BUSD committed…

Population exposure to heat-related extremes: Demographic change vs climate change

NASA Astrophysics Data System (ADS)

Jones, B.; O'Neill, B. C.; Tebaldi, C.; Oleson, K. W.

2014-12-01

Extreme heat events are projected to increase in frequency and intensity in the coming decades [1]. The physical effects of extreme heat on human populations are well-documented, and anticipating changes in future exposure to extreme heat is a key component of adequate planning/mitigation [2, 3]. Exposure to extreme heat depends not only on changing climate, but also on changes in the size and spatial distribution of the human population. Here we focus on systematically quantifying exposure to extreme heat as a function of both climate and population change. We compare exposure outcomes across multiple global climate and spatial population scenarios, and characterize the relative contributions of each to population exposure to extreme heat. We consider a 2 x 2 matrix of climate and population output, using projections of heat extremes corresponding to RCP 4.5 and RCP 8.5 from the NCAR community land model, and spatial population projections for SSP 3 and SSP 5 from the NCAR spatial population downscaling model. Our primary comparison is across RCPs - exposure outcomes from RCP 4.5 versus RCP 8.5 - paying particular attention to how variation depends on the choice of SSP in terms of aggregate global and regional exposure, as well as the spatial distribution of exposure. We assess how aggregate exposure changes based on the choice of SSP, and which driver is more important, population or climate change (i.e. does that outcome vary more as a result of RCP or SSP). We further decompose the population component to analyze the contributions of total population change, migration, and changes in local spatial structure. Preliminary results from a similar study of the US suggests a four-to-six fold increase in total exposure by the latter half of the 21st century. Changes in population are as important as changes in climate in driving this outcome, and there is regional variation in the relative importance of each. Aggregate population growth, as well as redistribution of the population across larger US regions, strongly affects outcomes while smaller-scale spatial patterns of population change have smaller effects. [1] Collins, M. et al. (2013) Contribution of WG I to the 5th AR of the IPCC[2] Romero-Lankao, P. et al (2014) Contribution of WG II to the 5th AR of the IPCC[3] Walsh, J. et al. (2014) The 3rd National Climate Assessment

Mapping past, present, and future climatic suitability for invasive Aedes aegypti and Aedes albopictus in the United States: a process-based modeling approach using CMIP5 downscaled climate scenarios

NASA Astrophysics Data System (ADS)

Donnelly, M. A. P.; Marcantonio, M.; Melton, F. S.; Barker, C. M.

2016-12-01

The ongoing spread of the mosquitoes, Aedes aegypti and Aedes albopictus, in the continental United States leaves new areas at risk for local transmission of dengue, chikungunya, and Zika viruses. All three viruses have caused major disease outbreaks in the Americas with infected travelers returning regularly to the U.S. The expanding range of these mosquitoes raises questions about whether recent spread has been enabled by climate change or other anthropogenic influences. In this analysis, we used downscaled climate scenarios from the NASA Earth Exchange Global Daily Downscaled Projections (NEX GDDP) dataset to model Ae. aegypti and Ae. albopictus population growth rates across the United States. We used a stage-structured matrix population model to understand past and present climatic suitability for these vectors, and to project future suitability under CMIP5 climate change scenarios. Our results indicate that much of the southern U.S. is suitable for both Ae. aegypti and Ae. albopictus year-round. In addition, a large proportion of the U.S. is seasonally suitable for mosquito population growth, creating the potential for periodic incursions into new areas. Changes in climatic suitability in recent decades for Ae. aegypti and Ae. albopictus have occurred already in many regions of the U.S., and model projections of future climate suggest that climate change will continue to reshape the range of Ae. aegypti and Ae. albopictus in the U.S., and potentially the risk of the viruses they transmit.

Mapping Past, Present, and Future Climatic Suitability for Invasive Aedes Aegypti and Aedes Albopictus in the United States: A Process-Based Modeling Approach Using CMIP5 Downscaled Climate Scenarios

NASA Technical Reports Server (NTRS)

Donnelly, Marisa Anne Pella; Marcantonio, Matteo; Melton, Forrest S.; Barker, Christopher M.

2016-01-01

The ongoing spread of the mosquitoes, Aedes aegypti and Aedes albopictus, in the continental United States leaves new areas at risk for local transmission of dengue, chikungunya, and Zika viruses. All three viruses have caused major disease outbreaks in the Americas with infected travelers returning regularly to the U.S. The expanding range of these mosquitoes raises questions about whether recent spread has been enabled by climate change or other anthropogenic influences. In this analysis, we used downscaled climate scenarios from the NASA Earth Exchange Global Daily Downscaled Projections (NEX GDDP) dataset to model Ae. aegypti and Ae. albopictus population growth rates across the United States. We used a stage-structured matrix population model to understand past and present climatic suitability for these vectors, and to project future suitability under CMIP5 climate change scenarios. Our results indicate that much of the southern U.S. is suitable for both Ae. aegypti and Ae. albopictus year-round. In addition, a large proportion of the U.S. is seasonally suitable for mosquito population growth, creating the potential for periodic incursions into new areas. Changes in climatic suitability in recent decades for Ae. aegypti and Ae. albopictus have occurred already in many regions of the U.S., and model projections of future climate suggest that climate change will continue to reshape the range of Ae. aegypti and Ae. albopictus in the U.S., and potentially the risk of the viruses they transmit.

National water, food, and trade modeling framework: The case of Egypt.

PubMed

Abdelkader, A; Elshorbagy, A; Tuninetti, M; Laio, F; Ridolfi, L; Fahmy, H; Hoekstra, A Y

2018-10-15

This paper introduces a modeling framework for the analysis of real and virtual water flows at national scale. The framework has two components: (1) a national water model that simulates agricultural, industrial and municipal water uses, and available water and land resources; and (2) an international virtual water trade model that captures national virtual water exports and imports related to trade in crops and animal products. This National Water, Food & Trade (NWFT) modeling framework is applied to Egypt, a water-poor country and the world's largest importer of wheat. Egypt's food and water gaps and the country's food (virtual water) imports are estimated over a baseline period (1986-2013) and projected up to 2050 based on four scenarios. Egypt's food and water gaps are growing rapidly as a result of steep population growth and limited water resources. The NWFT modeling framework shows the nexus of the population dynamics, water uses for different sectors, and their compounding effects on Egypt's food gap and water self-sufficiency. The sensitivity analysis reveals that for solving Egypt's water and food problem non-water-based solutions like educational, health, and awareness programs aimed at lowering population growth will be an essential addition to the traditional water resources development solution. Both the national and the global models project similar trends of Egypt's food gap. The NWFT modeling framework can be easily adapted to other nations and regions. Copyright © 2018. Published by Elsevier B.V.

Economic impact of a Medicaid population health management program.

PubMed

Rust, George; Strothers, Harry; Miller, William Johnson; McLaren, Susan; Moore, Barbara; Sambamoorthi, Usha

2011-10-01

A population health management program was implemented to assess growth in health care expenditures for the disabled segment of Georgia's Medicaid population before and during the first year of a population health outcomes management program, and to compare those expenditures with projected costs based on various cost inflation trend assumptions. A retrospective, nonexperimental approach was used to analyze claims data from Georgia Medicaid claims files for all program-eligible persons for each relevant time period (intent-to-treat basis). These included all non-Medicare, noninstitutionalized Medicaid aged-blind-disabled adults older than 18 years of age. Comparisons of health care expenditures and utilization were made between base year (2003-2004) and performance year one (2006-2007), and of the difference between actual expenditures incurred in the performance year vs. projected expenditures based on various cost inflation assumptions. Demographic characteristics and clinical complexity of the population (as measured by the Chronic Illness and Disability Payment System risk score) actually increased from baseline to implementation. Actual expenditures were less than projected expenditures using any relevant medical inflation assumption. Actual expenditures were less than projected expenditures by $9.82 million when using a conservative US general medical inflation rate, by $43.6 million using national Medicaid cost trends, and by $106 million using Georgia Medicaid's own cost projections for the non-dually eligible disabled segment of Medicaid enrollees. Quadratic growth curve modeling also demonstrated a lower rate of increase in total expenditures. The rate of increase in expenditures was lower over the first year of program implementation compared with baseline. Weighted utilization rates were also lower in high-cost categories, such as inpatient days, despite increases in the risk profile of the population. Varying levels of cost avoidance could be inferred from differences between actual and projected expenditures using each of the health-related inflation assumptions.

Climate Modelling Shows Increased Risk to Eucalyptus sideroxylon on the Eastern Coast of Australia Compared to Eucalyptus albens

PubMed Central

Shabani, Farzin; Ahmadi, Mohsen

2017-01-01

Aim: To identify the extent and direction of range shift of Eucalyptus sideroxylon and E. albens in Australia by 2050 through an ensemble forecast of four species distribution models (SDMs). Each was generated using four global climate models (GCMs), under two representative concentration pathways (RCPs). Location: Australia. Methods: We used four SDMs of (i) generalized linear model, (ii) MaxEnt, (iii) random forest, and (iv) boosted regression tree to construct SDMs for species E. sideroxylon and E. albens under four GCMs including (a) MRI-CGCM3, (b) MIROC5, (c) HadGEM2-AO and (d) CCSM4, under two RCPs of 4.5 and 6.0. Here, the true skill statistic (TSS) index was used to assess the accuracy of each SDM. Results: Results showed that E. albens and E. sideroxylon will lose large areas of their current suitable range by 2050 and E. sideroxylon is projected to gain in eastern and southeastern Australia. Some areas were also projected to remain suitable for each species between now and 2050. Our modelling showed that E. sideroxylon will lose suitable habitat on the western side and will not gain any on the eastern side because this region is one the most heavily populated areas in the country, and the populated areas are moving westward. The predicted decrease in E. sideroxylon’s distribution suggests that land managers should monitor its population closely, and evaluate whether it meets criteria for a protected legal status. Main conclusions: Both Eucalyptus sideroxylon and E. albens will be negatively affected by climate change and it is projected that E. sideroxylon will be at greater risk of losing habitat than E. albens. PMID:29186755

Effect of climate change on marine ecosystems

NASA Astrophysics Data System (ADS)

Vikebo, F. B.; Sundby, S.; Aadlandsvik, B.; Fiksen, O.

2003-04-01

As a part of the INTEGRATION project, headed by Potsdam Institute for Climate Impact Research, funded by the German Research Council, the impact of climate change scenarios on marine fish populations will be addressed on a spesific population basis and will focus on fish populations in the northern North Atlantic with special emphasis on cod. The approach taken will mainly be a modelling study supported by analysis of existing data on fish stocks and climate. Through down-scaling and nesting techniques, various climate change scenarios with reduced THC in the North Atlantic will be investigated with higher spatial resolution for selected shelf areas. The hydrodynamical model used for the regional ocean modeling is ROMS (http://marine.rutgers.edu/po/models/roms/). An individual based model will be implemented into the larval drift module to simulate growth of the larvae along the drift paths.

Projecting the Population-level Effects of Mercury on the Common Loon in the Northeast

NASA Astrophysics Data System (ADS)

Evers, D. C.; Mitro, M. G.; Gleason, T. R.

2001-05-01

The Common Loon (Gavia immer) is a top-level predator in aquatic systems and is at risk to mercury contamination. This risk is of particular concern in the Northeast, the region of North America in which loons have the highest mean body concentration of methylmercury (MeHg). We used matrix population models to project the population-level effects of mercury on loons in four states in the Northeast (New York, Vermont, New Hampshire, and Maine) exhibiting different levels of risk to MeHg. Four categories of risk to MeHg (low, moderate, high, and extra high) were established based on MeHg levels observed in loons and associated effects observed at the individual and population levels in the field (e.g., behavior and reproductive success). We parameterized deterministic matrix population models using survival estimates from a 12-year band-resight data set and productivity estimates from a 25-year data set of nesting loon observations in NH. The juvenile loon survival rate was 0.55 (minimum) and 0.63 (maximum) (ages 1-3), and the adult loon survival rate was 0.95 (ages 4-30). The mean age at first reproduction was 7. The mean fertility was 0.26 fledgelings per individual at low to moderate risk; there were 53% fewer fledged young per individual at high to extra high risk. Productivity was weighted by risk for each state. The portion of the breeding population at high to extra high risk was 10% in NY, 15% in VT, 17% in NH, and 28% in ME. We also constructed a stochastic model in which productivity was randomly selected in each time step from the 25 estimates in the NH data set. Model results indicated a negative population growth rate for some states. There was a decreasing trend in population growth rate as the percentage of the loon population at high to extra high risk increased. The stochastic model showed that the population growth rate varied over a range of about 0.05 from year to year, and this range decreased as the percentage of the loon population at high to extra high risk increased. These results suggest that an increase in risk to mercury that effects a change in reproductive success may have a negative population-level effect on loons.

A trait-based approach for predicting species responses to environmental change from sparse data: how well might terrestrial mammals track climate change?

PubMed

Santini, Luca; Cornulier, Thomas; Bullock, James M; Palmer, Stephen C F; White, Steven M; Hodgson, Jenny A; Bocedi, Greta; Travis, Justin M J

2016-07-01

Estimating population spread rates across multiple species is vital for projecting biodiversity responses to climate change. A major challenge is to parameterise spread models for many species. We introduce an approach that addresses this challenge, coupling a trait-based analysis with spatial population modelling to project spread rates for 15 000 virtual mammals with life histories that reflect those seen in the real world. Covariances among life-history traits are estimated from an extensive terrestrial mammal data set using Bayesian inference. We elucidate the relative roles of different life-history traits in driving modelled spread rates, demonstrating that any one alone will be a poor predictor. We also estimate that around 30% of mammal species have potential spread rates slower than the global mean velocity of climate change. This novel trait-space-demographic modelling approach has broad applicability for tackling many key ecological questions for which we have the models but are hindered by data availability. © 2016 The Authors. Global Change Biology Published by John Wiley & Sons Ltd.

Erosion of lizard diversity by climate change and altered thermal niches.

PubMed

Sinervo, Barry; Méndez-de-la-Cruz, Fausto; Miles, Donald B; Heulin, Benoit; Bastiaans, Elizabeth; Villagrán-Santa Cruz, Maricela; Lara-Resendiz, Rafael; Martínez-Méndez, Norberto; Calderón-Espinosa, Martha Lucía; Meza-Lázaro, Rubi Nelsi; Gadsden, Héctor; Avila, Luciano Javier; Morando, Mariana; De la Riva, Ignacio J; Victoriano Sepulveda, Pedro; Rocha, Carlos Frederico Duarte; Ibargüengoytía, Nora; Aguilar Puntriano, César; Massot, Manuel; Lepetz, Virginie; Oksanen, Tuula A; Chapple, David G; Bauer, Aaron M; Branch, William R; Clobert, Jean; Sites, Jack W

2010-05-14

It is predicted that climate change will cause species extinctions and distributional shifts in coming decades, but data to validate these predictions are relatively scarce. Here, we compare recent and historical surveys for 48 Mexican lizard species at 200 sites. Since 1975, 12% of local populations have gone extinct. We verified physiological models of extinction risk with observed local extinctions and extended projections worldwide. Since 1975, we estimate that 4% of local populations have gone extinct worldwide, but by 2080 local extinctions are projected to reach 39% worldwide, and species extinctions may reach 20%. Global extinction projections were validated with local extinctions observed from 1975 to 2009 for regional biotas on four other continents, suggesting that lizards have already crossed a threshold for extinctions caused by climate change.

Less than 2 °C warming by 2100 unlikely

NASA Astrophysics Data System (ADS)

Raftery, Adrian E.; Zimmer, Alec; Frierson, Dargan M. W.; Startz, Richard; Liu, Peiran

2017-09-01

The recently published Intergovernmental Panel on Climate Change (IPCC) projections to 2100 give likely ranges of global temperature increase in four scenarios for population, economic growth and carbon use. However, these projections are not based on a fully statistical approach. Here we use a country-specific version of Kaya's identity to develop a statistically based probabilistic forecast of CO2 emissions and temperature change to 2100. Using data for 1960-2010, including the UN's probabilistic population projections for all countries, we develop a joint Bayesian hierarchical model for Gross Domestic Product (GDP) per capita and carbon intensity. We find that the 90% interval for cumulative CO2 emissions includes the IPCC's two middle scenarios but not the extreme ones. The likely range of global temperature increase is 2.0-4.9 °C, with median 3.2 °C and a 5% (1%) chance that it will be less than 2 °C (1.5 °C). Population growth is not a major contributing factor. Our model is not a `business as usual' scenario, but rather is based on data which already show the effect of emission mitigation policies. Achieving the goal of less than 1.5 °C warming will require carbon intensity to decline much faster than in the recent past.

The no-project alternative analysis: An early product of the Tahoe Decision Support System

USGS Publications Warehouse

Halsing, David L.; Hessenflow, Mark L.; Wein, Anne

2005-01-01

We report on the development of a No-project alternative analysis (NPAA) or “business as usual” scenario with respect to a 20-year projection of 21 indicators of environmental and socioeconomic conditions in the Lake Tahoe Basin for the Tahoe Regional Planning Agency (TRPA). Our effort was inspired by earlier work that investigated the tradeoffs between an environmental and an economic objective. The NPAA study has implications for a longer term goal of building a Tahoe Decision Support System (TDSS) to assist the TRPA and other Basin agencies in assessing the outcomes of management strategies. The NPAA assumes no major deviations from current management practices or from recent environmental or societal trends and planned Environmental Improvement Program (EIP) projects. Quantitative “scenario generation” tools were constructed to simulate site-specific land uses, various population categories, and associated vehicle miles traveled. Projections of each indicator’s attainment status were made by building visual conceptual models of the relevant natural and social processes, extrapolating trends, and using available models, research, and expert opinion. We present results of the NPAA, projected indicator status, key factors affecting the indicators, indicator functionality, and knowledge gaps. One important result is that current management practices may slow the loss or degradation of environmental qualities but not halt or reverse it. Our analysis also predicts an increase in recreation and commuting into and within the basin, primarily in private vehicles. Private vehicles, which are a critical mechanism by which the Basin population affects the surrounding environment, are a key determinant of air-quality indicators, a source of particulate matter affecting Secchi depth, a source of noise, and a factor in recreational and scenic quality, largely owing to congestion. Key uncertainties in the NPAA include climate change, EIP project effectiveness, and external population, economic activity, and air pollution.

Uncertainty in Population Growth Rates: Determining Confidence Intervals from Point Estimates of Parameters

PubMed Central

Devenish Nelson, Eleanor S.; Harris, Stephen; Soulsbury, Carl D.; Richards, Shane A.; Stephens, Philip A.

2010-01-01

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. PMID:21049049

Privacy by Design at Population Data BC: a case study describing the technical, administrative, and physical controls for privacy-sensitive secondary use of personal information for research in the public interest.

PubMed

Pencarrick Hertzman, Caitlin; Meagher, Nancy; McGrail, Kimberlyn M

2013-01-01

Population Data BC (PopData) is an innovative leader in facilitating access to linked data for population health research. Researchers from academic institutions across Canada work with PopData to submit data access requests for projects involving linked administrative data, with or without their own researcher-collected data. PopData and its predecessor-the British Columbia Linked Health Database-have facilitated over 350 research projects analyzing a broad spectrum of population health issues. PopData embeds privacy in every aspect of its operations. This case study focuses on how implementing the Privacy by Design model protects privacy while supporting access to individual-level data for research in the public interest. It explores challenges presented by legislation, stewardship, and public perception and demonstrates how PopData achieves both operational efficiencies and due diligence.

Privacy by Design at Population Data BC: a case study describing the technical, administrative, and physical controls for privacy-sensitive secondary use of personal information for research in the public interest

PubMed Central

Pencarrick Hertzman, Caitlin; Meagher, Nancy; McGrail, Kimberlyn M

2013-01-01

Population Data BC (PopData) is an innovative leader in facilitating access to linked data for population health research. Researchers from academic institutions across Canada work with PopData to submit data access requests for projects involving linked administrative data, with or without their own researcher-collected data. PopData and its predecessor—the British Columbia Linked Health Database—have facilitated over 350 research projects analyzing a broad spectrum of population health issues. PopData embeds privacy in every aspect of its operations. This case study focuses on how implementing the Privacy by Design model protects privacy while supporting access to individual-level data for research in the public interest. It explores challenges presented by legislation, stewardship, and public perception and demonstrates how PopData achieves both operational efficiencies and due diligence. PMID:22935136

Current and Projected Heat-Related Morbidity and Mortality in Rhode Island

PubMed Central

Kingsley, Samantha L.; Eliot, Melissa N.; Gold, Julia; Vanderslice, Robert R.; Wellenius, Gregory A.

2015-01-01

Background: Climate change is expected to cause increases in heat-related mortality, especially among the elderly and very young. However, additional studies are needed to clarify the effects of heat on morbidity across all age groups and across a wider range of temperatures. Objectives: We aimed to estimate the impact of current and projected future temperatures on morbidity and mortality in Rhode Island. Methods: We used Poisson regression models to estimate the association between daily maximum temperature and rates of all-cause and heat-related emergency department (ED) admissions and all-cause mortality. We then used downscaled Coupled Model Intercomparison Project Phase 5 (CMIP5; a standardized set of climate change model simulations) projections to estimate the excess morbidity and mortality that would be observed if this population were exposed to the temperatures projected for 2046–2053 and 2092–2099 under two representative concentration pathways (RCP): RCP 8.5 and 4.5. Results: Between 2005 and 2012, an increase in maximum daily temperature from 75 to 85°F was associated with 1.3% and 23.9% higher rates of all-cause and heat-related ED visits, respectively. The corresponding effect estimate for all-cause mortality from 1999 through 2011 was 4.0%. The association with all-cause ED admissions was strongest for those < 18 or ≥ 65 years of age, whereas the association with heat-related ED admissions was most pronounced among 18- to 64-year-olds. If this Rhode Island population were exposed to temperatures projected under RCP 8.5 for 2092–2099, we estimate that there would be 1.2% (range, 0.6–1.6%) and 24.4% (range, 6.9–41.8%) more all-cause and heat-related ED admissions, respectively, and 1.6% (range, 0.8–2.1%) more deaths annually between April and October. Conclusions: With all other factors held constant, our findings suggest that the current population of Rhode Island would experience substantially higher morbidity and mortality if maximum daily temperatures increase further as projected. Citation: Kingsley SL, Eliot MN, Gold J, Vanderslice RR, Wellenius GA. 2016. Current and projected heat-related morbidity and mortality in Rhode Island. Environ Health Perspect 124:460–467; http://dx.doi.org/10.1289/ehp.1408826 PMID:26251954

Robust changes in the socio-climate risk over CONUS by mid 21st century

NASA Astrophysics Data System (ADS)

Ashfaq, M.; Rastogi, D.; Batibeniz, F.; Alifa, M.; Pagán, B. R.; Bonds, B. W.; Pal, J. S.; Diffenbaugh, N. S.; Preston, B. L.

2017-12-01

Using high-resolution near-term ensemble projections of hydro-climatic changes, we investigate impacts of climate change on natural and human systems across the CONUS. Climate projections are based a hybrid downscaling approach where a combination of regional and hydrological models are used to downscales 11 Global Climate Models from the 5th phase of Coupled Model Inter-comparison Project to 4km horizontal grid spacing for 41 years in the historical period (1965-2005) and 41 years in the near-term future period (2010-2050) under Representative Concentration Pathway 8.5. Should emissions continue to rise, climatic changes will likely intensify the regional hydrological cycle over CONUS through the acceleration of the historical trends in cold, warm and wet extremes. Our results show robust changes in the occurrence of severe weather conditions and in the likelihood of ice, freezing rain and snowstorms that may have disruptive impact on large human population across the U.S. More summer like conditions will also drive increase in cooling demands and a net increase in the energy consumption over many regions. We further use an integrated vulnerability index that combines human exposure to different climate extremes (hot, cold, wet and dry) and changes in socioeconomic pathways (due to changes in population and income levels), to reveal that future exposure to potentially damaging climatic conditions will likely increase manifold for population living in major urban centers in California, Texas, Florida, Michigan, Illinois and Northeast. With the current trajectory of emissions, these results warrant that a large human population across the U.S. may feel the impacts of climate change within its lifespan.

Combining dispersal, landscape connectivity and habitat suitability to assess climate-induced changes in the distribution of Cunningham's skink, Egernia cunninghami.

PubMed

Ofori, Benjamin Y; Stow, Adam J; Baumgartner, John B; Beaumont, Linda J

2017-01-01

The ability of species to track their climate niche is dependent on their dispersal potential and the connectivity of the landscape matrix linking current and future suitable habitat. However, studies modeling climate-driven range shifts rarely address the movement of species across landscapes realistically, often assuming "unlimited" or "no" dispersal. Here, we incorporate dispersal rate and landscape connectivity with a species distribution model (Maxent) to assess the extent to which the Cunningham's skink (Egernia cunninghami) may be capable of tracking spatial shifts in suitable habitat as climate changes. Our model was projected onto four contrasting, but equally plausible, scenarios describing futures that are (relative to now) hot/wet, warm/dry, hot/with similar precipitation and warm/wet, at six time horizons with decadal intervals (2020-2070) and at two spatial resolutions: 1 km and 250 m. The size of suitable habitat was projected to decline 23-63% at 1 km and 26-64% at 250 m, by 2070. Combining Maxent output with the dispersal rate of the species and connectivity of the intervening landscape matrix showed that most current populations in regions projected to become unsuitable in the medium to long term, will be unable to shift the distance necessary to reach suitable habitat. In particular, numerous populations currently inhabiting the trailing edge of the species' range are highly unlikely to be able to disperse fast enough to track climate change. Unless these populations are capable of adaptation they are likely to be extirpated. We note, however, that the core of the species distribution remains suitable across the broad spectrum of climate scenarios considered. Our findings highlight challenges faced by philopatric species and the importance of adaptation for the persistence of peripheral populations under climate change.

Assessment of changes in nutrient and sediment delivery to and carbon accumulation in coastal oceans of the Eastern United States

NASA Astrophysics Data System (ADS)

Bergamaschi, B. A.; Smith, R. A.; Shih, J. S.; Sohl, T. L.; Sleeter, B. M.; Zhu, Z.

2014-12-01

Land-use and land-cover distributions are primary determinants of terrestrial fluxes of sediments and nutrients to coastal oceans. Sediment and nutrient delivery to coastal waters have already been significantly altered by changes in population and land use, resulting in modified patterns of coastal production and carbon storage. Continued population growth and increasing agricultural areal extent and intensity are expected to accelerate these changes. The USGS LandCarbon project developed prospective future land use and land cover projections based on IPCC scenarios A1b, A2 and B1 to 2050 as the basis for a multitude of biogeochemical assessments. We assessed the impacts on delivery of nutrients and sediments to the coastal ocean, and concomitant carbon storage. Fluxes were estimated using the SPARROW model, calibrated on historical water quality measurements. Significantly greater fluxes of nutrients and sediments to coastal waters by 2050 are projected by the model. For example, for the Eastern United States, nitrate fluxes for 2050 are projected to be16 to 52 percent higher than the baseline year, depending on scenario. As a consequence, an associated increase in the frequency and duration of coastal and estuarine hypoxia events and harmful algal blooms could be expected. Model estimates indicate that these prospective future nutrient and sediment fluxes will increase carbon storage rates in coastal waters by 18 to 56 percent in some regions.

Scalable Entity-Based Modeling of Population-Based Systems, Final LDRD Report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cleary, A J; Smith, S G; Vassilevska, T K

2005-01-27

The goal of this project has been to develop tools, capabilities and expertise in the modeling of complex population-based systems via scalable entity-based modeling (EBM). Our initial focal application domain has been the dynamics of large populations exposed to disease-causing agents, a topic of interest to the Department of Homeland Security in the context of bioterrorism. In the academic community, discrete simulation technology based on individual entities has shown initial success, but the technology has not been scaled to the problem sizes or computational resources of LLNL. Our developmental emphasis has been on the extension of this technology to parallelmore » computers and maturation of the technology from an academic to a lab setting.« less

Wildfire, climate, and invasive grass interactions negatively impact an indicator species by reshaping sagebrush ecosystems.

PubMed

Coates, Peter S; Ricca, Mark A; Prochazka, Brian G; Brooks, Matthew L; Doherty, Kevin E; Kroger, Travis; Blomberg, Erik J; Hagen, Christian A; Casazza, Michael L

2016-10-25

Iconic sagebrush ecosystems of the American West are threatened by larger and more frequent wildfires that can kill sagebrush and facilitate invasion by annual grasses, creating a cycle that alters sagebrush ecosystem recovery post disturbance. Thwarting this accelerated grass-fire cycle is at the forefront of current national conservation efforts, yet its impacts on wildlife populations inhabiting these ecosystems have not been quantified rigorously. Within a Bayesian framework, we modeled 30 y of wildfire and climatic effects on population rates of change of a sagebrush-obligate species, the greater sage-grouse, across the Great Basin of western North America. Importantly, our modeling also accounted for variation in sagebrush recovery time post fire as determined by underlying soil properties that influence ecosystem resilience to disturbance and resistance to invasion. Our results demonstrate that the cumulative loss of sagebrush to direct and indirect effects of wildfire has contributed strongly to declining sage-grouse populations over the past 30 y at large spatial scales. Moreover, long-lasting effects from wildfire nullified pulses of sage-grouse population growth that typically follow years of higher precipitation. If wildfire trends continue unabated, model projections indicate sage-grouse populations will be reduced to 43% of their current numbers over the next three decades. Our results provide a timely example of how altered fire regimes are disrupting recovery of sagebrush ecosystems and leading to substantial declines of a widespread indicator species. Accordingly, we present scenario-based stochastic projections to inform conservation actions that may help offset the adverse effects of wildfire on sage-grouse and other wildlife populations.

Wildfire, climate, and invasive grass interactions negatively impact an indicator species by reshaping sagebrush ecosystems

USGS Publications Warehouse

Coates, Peter S.; Ricca, Mark; Prochazka, Brian; Brooks, Matthew L.; Doherty, Kevin E.; Kroger, Travis; Blomberg, Erik J.; Hagen, Christian A.; Casazza, Michael L.

2016-01-01

Iconic sagebrush ecosystems of the American West are threatened by larger and more frequent wildfires that can kill sagebrush and facilitate invasion by annual grasses, creating a cycle that alters sagebrush ecosystem recovery post disturbance. Thwarting this accelerated grass–fire cycle is at the forefront of current national conservation efforts, yet its impacts on wildlife populations inhabiting these ecosystems have not been quantified rigorously. Within a Bayesian framework, we modeled 30 y of wildfire and climatic effects on population rates of change of a sagebrush-obligate species, the greater sage-grouse, across the Great Basin of western North America. Importantly, our modeling also accounted for variation in sagebrush recovery time post fire as determined by underlying soil properties that influence ecosystem resilience to disturbance and resistance to invasion. Our results demonstrate that the cumulative loss of sagebrush to direct and indirect effects of wildfire has contributed strongly to declining sage-grouse populations over the past 30 y at large spatial scales. Moreover, long-lasting effects from wildfire nullified pulses of sage-grouse population growth that typically follow years of higher precipitation. If wildfire trends continue unabated, model projections indicate sage-grouse populations will be reduced to 43% of their current numbers over the next three decades. Our results provide a timely example of how altered fire regimes are disrupting recovery of sagebrush ecosystems and leading to substantial declines of a widespread indicator species. Accordingly, we present scenario-based stochastic projections to inform conservation actions that may help offset the adverse effects of wildfire on sage-grouse and other wildlife populations.

Modelling Future Cardiovascular Disease Mortality in the United States: National Trends and Racial and Ethnic Disparities

PubMed Central

Pearson-Stuttard, Jonathan; Guzman-Castillo, Maria; Penalvo, Jose L.; Rehm, Colin D.; Afshin, Ashkan; Danaei, Goodarz; Kypridemos, Chris; Gaziano, Tom; Mozaffarian, Dariush; Capewell, Simon; O’Flaherty, Martin

2016-01-01

Background Accurate forecasting of cardiovascular disease (CVD) mortality is crucial to guide policy and programming efforts. Prior forecasts have often not incorporated past trends in rates of reduction in CVD mortality. This creates uncertainties about future trends in CVD mortality and disparities. Methods and Results To forecast US CVD mortality and disparities to 2030, we developed a hierarchical Bayesian model to determine and incorporate prior age, period and cohort (APC) effects from 1979–2012, stratified by age, gender and race; which we combined with expected demographic shifts to 2030. Data sources included the National Vital Statistics System, SEER single year population estimates, and US Bureau of Statistics 2012 National Population projections. We projected coronary disease and stroke deaths to 2030, first based on constant APC effects at 2012 values, as most commonly done (conventional); and then using more rigorous projections incorporating expected trends in APC effects (trend-based). We primarily evaluated absolute mortality. The conventional model projected total coronary and stroke deaths by 2030 to increase by approximately 18% (67,000 additional coronary deaths/year) and 50% (64,000 additional stroke deaths/year). Conversely, the trend-based model projected that coronary mortality would fall by 2030 by approximately 27% (79,000 fewer deaths/year); and stroke mortality would remain unchanged (200 fewer deaths/year). Health disparities will be improved in stroke deaths, but not coronary deaths. Conclusions After accounting for prior mortality trends and expected demographic shifts, total US coronary deaths are expected to decline, while stroke mortality will remain relatively constant. Health disparities in stroke, but not coronary, deaths will be improved but not eliminated. These APC approaches offer more plausible predictions than conventional estimates. PMID:26846769

Increasing Prediction the Original Final Year Project of Student Using Genetic Algorithm

NASA Astrophysics Data System (ADS)

Saragih, Rijois Iboy Erwin; Turnip, Mardi; Sitanggang, Delima; Aritonang, Mendarissan; Harianja, Eva

2018-04-01

Final year project is very important forgraduation study of a student. Unfortunately, many students are not seriouslydidtheir final projects. Many of studentsask for someone to do it for them. In this paper, an application of genetic algorithms to predict the original final year project of a studentis proposed. In the simulation, the data of the final project for the last 5 years is collected. The genetic algorithm has several operators namely population, selection, crossover, and mutation. The result suggest that genetic algorithm can do better prediction than other comparable model. Experimental results of predicting showed that 70% was more accurate than the previous researched.

The evolution of labile traits in sex- and age-structured populations.

PubMed

Childs, Dylan Z; Sheldon, Ben C; Rees, Mark

2016-03-01

Many quantitative traits are labile (e.g. somatic growth rate, reproductive timing and investment), varying over the life cycle as a result of behavioural adaptation, developmental processes and plastic responses to the environment. At the population level, selection can alter the distribution of such traits across age classes and among generations. Despite a growing body of theoretical research exploring the evolutionary dynamics of labile traits, a data-driven framework for incorporating such traits into demographic models has not yet been developed. Integral projection models (IPMs) are increasingly being used to understand the interplay between changes in labile characters, life histories and population dynamics. One limitation of the IPM approach is that it relies on phenotypic associations between parents and offspring traits to capture inheritance. However, it is well-established that many different processes may drive these associations, and currently, no clear consensus has emerged on how to model micro-evolutionary dynamics in an IPM framework. We show how to embed quantitative genetic models of inheritance of labile traits into age-structured, two-sex models that resemble standard IPMs. Commonly used statistical tools such as GLMs and their mixed model counterparts can then be used for model parameterization. We illustrate the methodology through development of a simple model of egg-laying date evolution, parameterized using data from a population of Great tits (Parus major). We demonstrate how our framework can be used to project the joint dynamics of species' traits and population density. We then develop a simple extension of the age-structured Price equation (ASPE) for two-sex populations, and apply this to examine the age-specific contributions of different processes to change in the mean phenotype and breeding value. The data-driven framework we outline here has the potential to facilitate greater insight into the nature of selection and its consequences in settings where focal traits vary over the lifetime through ontogeny, behavioural adaptation and phenotypic plasticity, as well as providing a potential bridge between theoretical and empirical studies of labile trait variation. © 2016 The Authors Journal of Animal Ecology published by John Wiley & Sons Ltd on behalf of British Ecological Society.

Assessing local population vulnerability to wind energy development with branching process models: an application to wind energy development

USGS Publications Warehouse

Erickson, Richard A.; Eager, Eric A.; Stanton, Jessica C.; Beston, Julie A.; Diffendorfer, James E.; Thogmartin, Wayne E.

2015-01-01

Quantifying the impact of anthropogenic development on local populations is important for conservation biology and wildlife management. However, these local populations are often subject to demographic stochasticity because of their small population size. Traditional modeling efforts such as population projection matrices do not consider this source of variation whereas individual-based models, which include demographic stochasticity, are computationally intense and lack analytical tractability. One compromise between approaches is branching process models because they accommodate demographic stochasticity and are easily calculated. These models are known within some sub-fields of probability and mathematical ecology but are not often applied in conservation biology and applied ecology. We applied branching process models to quantitatively compare and prioritize species locally vulnerable to the development of wind energy facilities. Specifically, we examined species vulnerability using branching process models for four representative species: A cave bat (a long-lived, low fecundity species), a tree bat (short-lived, moderate fecundity species), a grassland songbird (a short-lived, high fecundity species), and an eagle (a long-lived, slow maturation species). Wind turbine-induced mortality has been observed for all of these species types, raising conservation concerns. We simulated different mortality rates from wind farms while calculating local extinction probabilities. The longer-lived species types (e.g., cave bats and eagles) had much more pronounced transitions from low extinction risk to high extinction risk than short-lived species types (e.g., tree bats and grassland songbirds). High-offspring-producing species types had a much greater variability in baseline risk of extinction than the lower-offspring-producing species types. Long-lived species types may appear stable until a critical level of incidental mortality occurs. After this threshold, the risk of extirpation for a local population may rapidly increase with only minimal increases in wind mortality. Conservation biologists and wildlife managers may need to consider this mortality pattern when issuing take permits and developing monitoring protocols for wind facilities. We also describe how our branching process models may be generalized across a wider range of species for a larger assessment project and then describe how our methods may be applied to other stressors in addition to wind.

The Pelagics Habitat Analysis Module (PHAM): Decision Support Tools for Pelagic Fisheries

NASA Astrophysics Data System (ADS)

Armstrong, E. M.; Harrison, D. P.; Kiefer, D.; O'Brien, F.; Hinton, M.; Kohin, S.; Snyder, S.

2009-12-01

PHAM is a project funded by NASA to integrate satellite imagery and circulation models into the management of commercial and threatened pelagic species. Specifically, the project merges data from fishery surveys, and fisheries catch and effort data with satellite imagery and circulation models to define the habitat of each species. This new information on habitat will then be used to inform population distribution and models of population dynamics that are used for management. During the first year of the project, we created two prototype modules. One module, which was developed for the Inter-American Tropical Tuna Commission, is designed to help improve information available to manage the tuna fisheries of the eastern Pacific Ocean. The other module, which was developed for the Coastal Pelagics Division of the Southwest Fishery Science Center, assists management of by-catch of mako, blue, and thresher sharks along the Californian coast. Both modules were built with the EASy marine geographic information system, which provides a 4 dimensional (latitude, longitude, depth, and time) home for integration of the data. The projects currently provide tools for automated downloading and geo-referencing of satellite imagery of sea surface temperature, height, and chlorophyll concentrations; output from JPL’s ECCO2 global circulation model and its ROM California current model; and gridded data from fisheries and fishery surveys. It also provides statistical tools for defining species habitat from these and other types of environmental data. These tools include unbalanced ANOVA, EOF analysis of satellite imagery, and multivariate search routines for fitting fishery data to transforms of the environmental data. Output from the projects consists of dynamic maps of the distribution of the species that are driven by the time series of satellite imagery and output from the circulation models. It also includes relationships between environmental variables and recruitment. During the talk, we will briefly demonstrate features of the software and present the results of our analyses of habitats.

Reintroducing Guanaco in the Upper Belt of Central Argentina: Using Population Viability Analysis to Evaluate Extinction Risk and Management Priorities

PubMed Central

Barri, Fernando Rafael

2016-01-01

Wildlife reintroduction is an increasingly used strategy to reverse anthropocene defaunation. For the purpose of ecosystem restoration, in 2007 the guanaco (Lama guanicoe) was reintroduced to the Quebrada del Condorito National Park, situated in the mountains of central Argentina. With the aim of developing management recommendations, the project included permanently monitoring the population to evaluate its dynamics and the ecological response of the individuals released into the area. Nine years later and after two releases of guanacos (113 individuals in 2007 without and 25 in 2011 with a pre-adaptation period), only 24 individuals, which conform three reproductive groups, and one group of solitary males were settled in the Park. Here I modeled a population viability analysis to evaluate extinction risk, using VORTEX software. Initial population structure, specified age distribution, mortality and reproductive rates, and mate monopolization recorded during field work were used in the model, whereas the remaining used demographic parameters, such as age of first offspring, maximum number of broods per year, mean foaling rate, and length of fecundity period, were taken from the literature. Each of the three different scenarios (without supplementation of individuals, and with a realistic and optimistic supplementation) and two possible catastrophic events (fires and food shortage) covering 100 years was repeated 1000 times. Even though the guanaco reintroduction project can be considered to have been partially successful since its start, the model predicts that the current reintroduced population could be extinct in the next few decades if no reinforcements occur, and that only a continuous supplementation can reach the probability that the population survives over the next 100 years. I conclude that, so far, the current population is at a high risk of extinction if further supplementation of individuals is discontinued. PMID:27741302

Reintroducing Guanaco in the Upper Belt of Central Argentina: Using Population Viability Analysis to Evaluate Extinction Risk and Management Priorities.

PubMed

Barri, Fernando Rafael

2016-01-01

Wildlife reintroduction is an increasingly used strategy to reverse anthropocene defaunation. For the purpose of ecosystem restoration, in 2007 the guanaco (Lama guanicoe) was reintroduced to the Quebrada del Condorito National Park, situated in the mountains of central Argentina. With the aim of developing management recommendations, the project included permanently monitoring the population to evaluate its dynamics and the ecological response of the individuals released into the area. Nine years later and after two releases of guanacos (113 individuals in 2007 without and 25 in 2011 with a pre-adaptation period), only 24 individuals, which conform three reproductive groups, and one group of solitary males were settled in the Park. Here I modeled a population viability analysis to evaluate extinction risk, using VORTEX software. Initial population structure, specified age distribution, mortality and reproductive rates, and mate monopolization recorded during field work were used in the model, whereas the remaining used demographic parameters, such as age of first offspring, maximum number of broods per year, mean foaling rate, and length of fecundity period, were taken from the literature. Each of the three different scenarios (without supplementation of individuals, and with a realistic and optimistic supplementation) and two possible catastrophic events (fires and food shortage) covering 100 years was repeated 1000 times. Even though the guanaco reintroduction project can be considered to have been partially successful since its start, the model predicts that the current reintroduced population could be extinct in the next few decades if no reinforcements occur, and that only a continuous supplementation can reach the probability that the population survives over the next 100 years. I conclude that, so far, the current population is at a high risk of extinction if further supplementation of individuals is discontinued.

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

Treesearch

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,...

An ecological model of the habitat mosaic in estuarine nursery areas: Part II – Projecting effects of sea level rise on fish production

EPA Science Inventory

Understanding the response of fish populations to habitat change mediated by sea level rise (SLR) is a key component of ecosystem-based management. Yet, no direct link has been established between habitat change due to SLR and fish population production. Here we take a coupled ...

Orbital Debris Shape Characterization Project Abstract

NASA Technical Reports Server (NTRS)

Pease, Jessie

2016-01-01

I have been working on a project to further our understanding of orbital debris by helping create a new dataset previously too complex to be implemented in past orbital debris propagation models. I am doing this by creating documentation and 3D examples and illustrations of the shape categories. Earlier models assumed all orbital debris to be spherical aluminum fragments. My project will help expand our knowledge of shape populations to 6 categories: Straight Needle/Rod/Cylinder, Bent Needle/Rod/Cylinder, Flat Plate, Bent Plate, Nugget/Parallelepiped/Spheroid, and Flexible. The last category, Flexible, is still up for discussion and may be modified. These categories will be used to characterize fragments in the DebriSat experiment.

Impact of the economic downturn on total joint replacement demand in the United States: updated projections to 2021.

PubMed

Kurtz, Steven M; Ong, Kevin L; Lau, Edmund; Bozic, Kevin J

2014-04-16

Few studies have explored the role of the National Health Expenditure and macroeconomics on the utilization of total joint replacement. The economic downturn has raised questions about the sustainability of growth for total joint replacement in the future. Previous projections of total joint replacement demand in the United States were based on data up to 2003 using a statistical methodology that neglected macroeconomic factors, such as the National Health Expenditure. Data from the Nationwide Inpatient Sample (1993 to 2010) were used with United States Census and National Health Expenditure data to quantify historical trends in total joint replacement rates, including the two economic downturns in the 2000s. Primary and revision hip and knee arthroplasty were identified using codes from the International Classification of Diseases, Ninth Revision, Clinical Modification. Projections in total joint replacement were estimated using a regression model incorporating the growth in population and rate of arthroplasties from 1993 to 2010 as a function of age, sex, race, and census region using the National Health Expenditure as the independent variable. The regression model was used in conjunction with government projections of National Health Expenditure from 2011 to 2021 to estimate future arthroplasty rates in subpopulations of the United States and to derive national estimates. The growth trend for the incidence of joint arthroplasty, for the overall United States population as well as for the United States workforce, was insensitive to economic downturns. From 2009 to 2010, the total number of procedures increased by 6.0% for primary total hip arthroplasty, 6.1% for primary total knee arthroplasty, 10.8% for revision total hip arthroplasty, and 13.5% for revision total knee arthroplasty. The National Health Expenditure model projections for primary hip replacement in 2020 were higher than a previously projected model, whereas the current model estimates for total knee arthroplasty were lower. Economic downturns in the 2000s did not substantially influence the national growth trends for hip and knee arthroplasty in the United States. These latest updated projections provide a basis for surgeons, hospitals, payers, and policy makers to plan for the future demand for total joint replacement surgery.

Performance Evaluation and Analysis of Rural Drinking Water Safety Project——A Case Study in Jiangsu, China

NASA Astrophysics Data System (ADS)

Du, Xiaorong

2017-04-01

Water is the basic condition for human survival and development. As China is the most populous country, rural drinking water safety problems are most conspicuous. Therefore, the Chinese government keeps increasing investment and has built a large number of rural drinking water safety projects. Scientific evaluation of project performance is of great significance to promote the sustainable operation of the project and the sustainable development of rural economy. Previous studies mainly focus on the economic benefits of the project, while ignoring the fact that the rural drinking water safety project is quasi-public goods, which has economic, social and ecological benefits. This paper establishes a comprehensive evaluation model for rural drinking water safety performance, which adapts the rules of "5E" (economy, efficiency, effectiveness, equity and environment) as the value orientation, and selects a rural drinking water safety project as object in case study at K District, which is in the north of Jiangsu Province, China. The results shows: 1) the comprehensive performance of K project is in good condition; 2) The performance of every part shows that the scores of criteria "efficiency", "environment" and "effect" are higher than the mean performance, while the "economy" is slightly lower than the mean and the "equity" is the lowest. 3) The performance of indicator layer shows that: the planned completion rate of project, the reduction rate of project cost and the penetration rate of water-use population are significantly lower than other indicators. Based on the achievements of previous studies and the characteristics of rural drinking water safety project, this study integrates the evaluation dimensions of equity and environment, which can contribute to a more comprehensive and systematic assessment of project performance and provide empirical data for performance evaluation and management of rural drinking water safety project. Key Words: Rural drinking water safety project; Performance evaluation; 5E rules; Comprehensive evaluation model

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

ERIC Educational Resources Information Center

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…

Estimating the impact of oyster restoration scenarios on transient fish production

USGS Publications Warehouse

McCoy, Elizabeth; Borrett, Stuart R.; LaPeyre, Megan K.; Peterson, Bradley J.

2017-01-01

Oyster reef restoration projects are increasing in number both to enhance oyster density and to retain valuable ecosystem services provided by oyster reefs. Although some oyster restoration projects have demonstrated success by increasing density and biomass of transient fish, it still remains a challenge to quantify the effects of oyster restoration on transient fish communities. We developed a bioenergetics model to assess the impact of selected oyster reef restoration scenarios on associated transient fish species. We used the model to analyze the impact of changes in (1) oyster population carrying capacity; (2) oyster population growth rate; and (3) diet preference of transient fish on oyster reef development and associated transient fish species. Our model results indicate that resident fish biomass is directly affected by oyster restoration and oyster biomass, and oyster restoration can have cascading impacts on transient fish biomass. Furthermore, the results highlight the importance of a favorable oyster population growth rate during early restoration years, as it can lead to rapid increases in mean oyster biomass and biomass of transient fish species. The model also revealed that a transient fish's diet solely dependent on oyster reef-derived prey could limit the biomass of transient fish species, emphasizing the importance of habitat connectivity in estuarine areas to enhance transient fish species biomass. Simple bioenergetics models can be developed to understand the dynamics of a system and make qualitative predictions of management and restoration scenarios.

Modeling the Complex Impacts of Timber Harvests to Find Optimal Management Regimes for Amazon Tidal Floodplain Forests

PubMed Central

Fortini, Lucas B.; Cropper, Wendell P.; Zarin, Daniel J.

2015-01-01

At the Amazon estuary, the oldest logging frontier in the Amazon, no studies have comprehensively explored the potential long-term population and yield consequences of multiple timber harvests over time. Matrix population modeling is one way to simulate long-term impacts of tree harvests, but this approach has often ignored common impacts of tree harvests including incidental damage, changes in post-harvest demography, shifts in the distribution of merchantable trees, and shifts in stand composition. We designed a matrix-based forest management model that incorporates these harvest-related impacts so resulting simulations reflect forest stand dynamics under repeated timber harvests as well as the realities of local smallholder timber management systems. Using a wide range of values for management criteria (e.g., length of cutting cycle, minimum cut diameter), we projected the long-term population dynamics and yields of hundreds of timber management regimes in the Amazon estuary, where small-scale, unmechanized logging is an important economic activity. These results were then compared to find optimal stand-level and species-specific sustainable timber management (STM) regimes using a set of timber yield and population growth indicators. Prospects for STM in Amazonian tidal floodplain forests are better than for many other tropical forests. However, generally high stock recovery rates between harvests are due to the comparatively high projected mean annualized yields from fast-growing species that effectively counterbalance the projected yield declines from other species. For Amazonian tidal floodplain forests, national management guidelines provide neither the highest yields nor the highest sustained population growth for species under management. Our research shows that management guidelines specific to a region’s ecological settings can be further refined to consider differences in species demographic responses to repeated harvests. In principle, such fine-tuned management guidelines could make management more attractive, thus bridging the currently prevalent gap between tropical timber management practice and regulation. PMID:26322896

Modeling the complex impacts of timber harvests to find optimal management regimes for Amazon tidal floodplain forests

USGS Publications Warehouse

Fortini, Lucas B.; Cropper, Wendell P.; Zarin, Daniel J.

2015-01-01

At the Amazon estuary, the oldest logging frontier in the Amazon, no studies have comprehensively explored the potential long-term population and yield consequences of multiple timber harvests over time. Matrix population modeling is one way to simulate long-term impacts of tree harvests, but this approach has often ignored common impacts of tree harvests including incidental damage, changes in post-harvest demography, shifts in the distribution of merchantable trees, and shifts in stand composition. We designed a matrix-based forest management model that incorporates these harvest-related impacts so resulting simulations reflect forest stand dynamics under repeated timber harvests as well as the realities of local smallholder timber management systems. Using a wide range of values for management criteria (e.g., length of cutting cycle, minimum cut diameter), we projected the long-term population dynamics and yields of hundreds of timber management regimes in the Amazon estuary, where small-scale, unmechanized logging is an important economic activity. These results were then compared to find optimal stand-level and species-specific sustainable timber management (STM) regimes using a set of timber yield and population growth indicators. Prospects for STM in Amazonian tidal floodplain forests are better than for many other tropical forests. However, generally high stock recovery rates between harvests are due to the comparatively high projected mean annualized yields from fast-growing species that effectively counterbalance the projected yield declines from other species. For Amazonian tidal floodplain forests, national management guidelines provide neither the highest yields nor the highest sustained population growth for species under management. Our research shows that management guidelines specific to a region’s ecological settings can be further refined to consider differences in species demographic responses to repeated harvests. In principle, such fine-tuned management guidelines could make management more attractive, thus bridging the currently prevalent gap between tropical timber management practice and regulation.

Strategies for Reforestation under Uncertain Future Climates: Guidelines for Alberta, Canada

PubMed Central

Gray, Laura K.; Hamann, Andreas

2011-01-01

Background Commercial forestry programs normally use locally collected seed for reforestation under the assumption that tree populations are optimally adapted to local environments. However, in western Canada this assumption is no longer valid because of climate trends that have occurred over the last several decades. The objective of this study is to show how we can arrive at reforestation recommendations with alternative species and genotypes that are viable under a majority of climate change scenarios. Methodology/Principal Findings In a case study for commercially important tree species of Alberta, we use an ecosystem-based bioclimate envelope modeling approach for western North America to project habitat for locally adapted populations of tree species using multi-model climate projections for the 2020s, 2050s and 2080s. We find that genotypes of species that are adapted to drier climatic conditions will be the preferred planting stock over much of the boreal forest that is commercially managed. Interestingly, no alternative species that are currently not present in Alberta can be recommended with any confidence. Finally, we observe large uncertainties in projections of suitable habitat that make reforestation planning beyond the 2050s difficult for most species. Conclusion/Significance More than 50,000 hectares of forests are commercially planted every year in Alberta. Choosing alternative planting stock, suitable for expected future climates, could therefore offer an effective climate change adaptation strategy at little additional cost. Habitat projections for locally adapted tree populations under observed climate change conform well to projections for the 2020s, which suggests that it is a safe strategy to change current reforestation practices and adapt to new climatic realities through assisted migration prescriptions. PMID:21853061

Projected trends in high-mortality heatwaves under different scenarios of climate, population, and adaptation in 82 US communities.

PubMed

Anderson, G Brooke; Oleson, Keith W; Jones, Bryan; Peng, Roger D

2018-02-01

Some rare heatwaves have extreme daily mortality impacts; moderate heatwaves have lower daily impacts but occur much more frequently at present and so account for large aggregated impacts. We applied health-based models to project trends in high-mortality heatwaves, including proportion of all heatwaves expected to be high-mortality, using the definition that a high-mortality heatwave increases mortality risk by ≥20 %. We projected these trends in 82 US communities in 2061-2080 under two scenarios of climate change (RCP4.5, RCP8.5), two scenarios of population change (SSP3, SSP5), and three scenarios of community adaptation to heat (none, lagged, on-pace) for large- and medium-ensemble versions of the National Center for Atmospheric Research's Community Earth System Model. More high-mortality heatwaves were expected compared to present under all scenarios except on-pace adaptation, and population exposure was expected to increase under all scenarios. At least seven more high-mortality heatwaves were expected in a twenty-year period in the 82 study communities under RCP8.5 than RCP4.5 when assuming no adaptation. However, high-mortality heatwaves were expected to remain <1 % of all heatwaves and heatwave exposure under all scenarios. Projections were most strongly influenced by the adaptation scenario- going from a scenario of on-pace to lagged adaptation or from lagged to no adaptation more than doubled the projected number of and exposure to high-mortality heatwaves. Based on our results, fewer high-mortality heatwaves are expected when following RCP4.5 versus RCP8.5 and under higher levels of adaptation, but high-mortality heatwaves are expected to remain a very small proportion of total heatwave exposure.

Community-based intervention packages facilitated by NGOs demonstrate plausible evidence for child mortality impact.

PubMed

Ricca, Jim; Kureshy, Nazo; LeBan, Karen; Prosnitz, Debra; Ryan, Leo

2014-03-01

Evidence exists that community-based intervention packages can have substantial child and newborn mortality impact, and may help more countries meet Millennium Development Goal 4 (MDG 4) targets. A non-governmental organization (NGO) project using such programming in Mozambique documented an annual decline in under-five mortality rate (U5MR) of 9.3% in a province in which Demographic and Health Survey (DHS) data showed a 4.2% U5MR decline during the same period. To test the generalizability of this finding, the same analysis was applied to a group of projects funded by the US Agency for International Development. Projects supported implementation of community-based intervention packages aimed at increasing use of health services while improving preventive and home-care practices for children under five. All projects collect baseline and endline population coverage data for key child health interventions. Twelve projects fitted the inclusion criteria. U5MR decline was estimated by modelling these coverage changes in the Lives Saved Tool (LiST) and comparing with concurrent measured DHS mortality data. Average coverage changes for all interventions exceeded average concurrent trends. When population coverage changes were modelled in LiST, they were estimated to give a child mortality improvement in the project area that exceeded concurrent secular trend in the subnational DHS region in 11 of 12 cases. The average improvement in modelled U5MR (5.8%) was more than twice the concurrent directly measured average decline (2.5%). NGO projects implementing community-based intervention packages appear to be effective in reducing child mortality in diverse settings. There is plausible evidence that they raised coverage for a variety of high-impact interventions and improved U5MR by more than twice the concurrent secular trend. All projects used community-based strategies that achieved frequent interpersonal contact for health behaviour change. Further study of the effectiveness and scalability of similar packages should be part of the effort to accelerate progress towards MDG 4.

Technoeconomic assumptions adopted for the development of a long-term electricity supply model for Cyprus.

PubMed

Taliotis, Constantinos; Taibi, Emanuele; Howells, Mark; Rogner, Holger; Bazilian, Morgan; Welsch, Manuel

2017-10-01

The generation mix of Cyprus has been dominated by oil products for decades. In order to conform with European Union and international legislation, a transformation of the supply system is called for. Energy system models can facilitate energy planning into the future, but a large volume of data is required to populate such models. The present data article provides information on key modelling assumptions and input data adopted with the aim of representing the electricity supply system of Cyprus in a separate research article. Data in regards to renewable energy technoeconomic characteristics and investment cost projections, fossil fuel price projections, storage technology characteristics and system operation assumptions are described in this article.

A Novel Application of Agent-based Modeling: Projecting Water Access and Availability Using a Coupled Hydrologic Agent-based Model in the Nzoia Basin, Kenya

NASA Astrophysics Data System (ADS)

Le, A.; Pricope, N. G.

2015-12-01

Projections indicate that increasing population density, food production, and urbanization in conjunction with changing climate conditions will place stress on water resource availability. As a result, a holistic understanding of current and future water resource distribution is necessary for creating strategies to identify the most sustainable means of accessing this resource. Currently, most water resource management strategies rely on the application of global climate predictions to physically based hydrologic models to understand potential changes in water availability. However, the need to focus on understanding community-level social behaviors that determine individual water usage is becoming increasingly evident, as predictions derived only from hydrologic models cannot accurately represent the coevolution of basin hydrology and human water and land usage. Models that are better equipped to represent the complexity and heterogeneity of human systems and satellite-derived products in place of or in conjunction with historic data significantly improve preexisting hydrologic model accuracy and application outcomes. We used a novel agent-based sociotechnical model that combines the Soil and Water Assessment Tool (SWAT) and Agent Analyst and applied it in the Nzoia Basin, an area in western Kenya that is becoming rapidly urbanized and industrialized. Informed by a combination of satellite-derived products and over 150 household surveys, the combined sociotechnical model provided unique insight into how populations self-organize and make decisions based on water availability. In addition, the model depicted how population organization and current management alter water availability currently and in the future.

Quantitative assessment of the importance of phenotypic plasticity in adaptation to climate change in wild bird populations.

PubMed

Vedder, Oscar; Bouwhuis, Sandra; Sheldon, Ben C

2013-07-01

Predictions about the fate of species or populations under climate change scenarios typically neglect adaptive evolution and phenotypic plasticity, the two major mechanisms by which organisms can adapt to changing local conditions. As a consequence, we have little understanding of the scope for organisms to track changing environments by in situ adaptation. Here, we use a detailed individual-specific long-term population study of great tits (Parus major) breeding in Wytham Woods, Oxford, UK to parameterise a mechanistic model and thus directly estimate the rate of environmental change to which in situ adaptation is possible. Using the effect of changes in early spring temperature on temporal synchrony between birds and a critical food resource, we focus in particular on the contribution of phenotypic plasticity to population persistence. Despite using conservative estimates for evolutionary and reproductive potential, our results suggest little risk of population extinction under projected local temperature change; however, this conclusion relies heavily on the extent to which phenotypic plasticity tracks the changing environment. Extrapolating the model to a broad range of life histories in birds suggests that the importance of phenotypic plasticity for adjustment to projected rates of temperature change increases with slower life histories, owing to lower evolutionary potential. Understanding the determinants and constraints on phenotypic plasticity in natural populations is thus crucial for characterising the risks that rapidly changing environments pose for the persistence of such populations.

The future impact of population growth and aging on coronary heart disease in China: projections from the Coronary Heart Disease Policy Model-China

PubMed Central

Moran, Andrew; Zhao, Dong; Gu, Dongfeng; Coxson, Pamela; Chen, Chung-Shiuan; Cheng, Jun; Liu, Jing; He, Jiang; Goldman, Lee

2008-01-01

Background China will experience an overall growth and aging of its adult population in coming decades. We used a computer model to forecast the future impact of these demographic changes on coronary heart disease (CHD) in China. Methods The CHD Policy Model is a validated state-transition, computer simulation of CHD on a national scale. China-specific CHD risk factor, incidence, case-fatality, and prevalence data were incorporated, and a CHD prediction model was generated from a Chinese cohort study and calibrated to age-specific Chinese mortality rates. Disability-adjusted life years (DALYs) due to CHD were calculated using standard methods. The projected population of China aged 35–84 years was entered, and CHD events, deaths, and DALYs were simulated over 2000–2029. CHD risk factors other than age and case-fatality were held at year 2000 levels. Sensitivity analyses tested uncertainty regarding CHD mortality coding, the proportion of total deaths attributable to CHD, and case-fatality. Results We predicted 7.8 million excess CHD events (a 69% increase) and 3.4 million excess CHD deaths (a 64% increase) in the decade 2020–2029 compared with 2000–2009. For 2030, we predicted 71% of almost one million annual CHD deaths will occur in persons ≥65 years old, while 67% of the growing annual burden of CHD death and disability will weigh on adults <65 years old. Substituting alternate CHD mortality assumptions led to 17–20% more predicted CHD deaths over 2000–2029, though the pattern of increases in CHD events and deaths over time remained. Conclusion We forecast that absolute numbers of CHD events and deaths will increase dramatically in China over 2010–2029, due to a growing and aging population alone. Recent data suggest CHD risk factor levels are increasing, so our projections may underestimate the extent of the potential CHD epidemic in China. PMID:19036167

Future Declines of Coronary Heart Disease Mortality in England and Wales Could Counter the Burden of Population Ageing

PubMed Central

Guzman Castillo, Maria; Gillespie, Duncan O. S.; Allen, Kirk; Bandosz, Piotr; Schmid, Volker; Capewell, Simon; O’Flaherty, Martin

2014-01-01

Background Coronary Heart Disease (CHD) remains a major cause of mortality in the United Kingdom. Yet predictions of future CHD mortality are potentially problematic due to population ageing and increase in obesity and diabetes. Here we explore future projections of CHD mortality in England & Wales under two contrasting future trend assumptions. Methods In scenario A, we used the conventional counterfactual scenario that the last-observed CHD mortality rates from 2011 would persist unchanged to 2030. The future number of deaths was calculated by applying those rates to the 2012–2030 population estimates. In scenario B, we assumed that the recent falling trend in CHD mortality rates would continue. Using Lee-Carter and Bayesian Age Period Cohort (BAPC) models, we projected the linear trends up to 2030. We validate our methods using past data to predict mortality from 2002–2011. Then, we computed the error between observed and projected values. Results In scenario A, assuming that 2011 mortality rates stayed constant by 2030, the number of CHD deaths would increase 62% or approximately 39,600 additional deaths. In scenario B, assuming recent declines continued, the BAPC model (the model with lowest error) suggests the number of deaths will decrease by 56%, representing approximately 36,200 fewer deaths by 2030. Conclusions The decline in CHD mortality has been reasonably continuous since 1979, and there is little reason to believe it will soon halt. The commonly used assumption that mortality will remain constant from 2011 therefore appears slightly dubious. By contrast, using the BAPC model and assuming continuing mortality falls offers a more plausible prediction of future trends. Thus, despite population ageing, the number of CHD deaths might halve again between 2011 and 2030. This has implications for how the potential benefits of future cardiovascular strategies might best be calculated and presented. PMID:24918442

An aging population and growing disease burden will require a large and specialized health care workforce by 2025.

PubMed

Dall, Timothy M; Gallo, Paul D; Chakrabarti, Ritasree; West, Terry; Semilla, April P; Storm, Michael V

2013-11-01

As the US population ages, the increasing prevalence of chronic disease and complex medical conditions will have profound implications for the future health care system. We projected future prevalence of selected diseases and health risk factors to model future demand for health care services for each person in a representative sample of the current and projected future population. Based on changing demographic characteristics and expanded medical coverage under the Affordable Care Act, we project that the demand for adult primary care services will grow by approximately 14 percent between 2013 and 2025. Vascular surgery has the highest projected demand growth (31 percent), followed by cardiology (20 percent) and neurological surgery, radiology, and general surgery (each 18 percent). Market indicators such as long wait times to obtain appointments suggest that the current supply of many specialists throughout the United States is inadequate to meet the current demand. Failure to train sufficient numbers and the correct mix of specialists could exacerbate already long wait times for appointments, reduce access to care for some of the nation's most vulnerable patients, and reduce patients' quality of life.

Fragmentation and thermal risks from climate change interact to affect persistence of native trout in the Colorado River basin.

PubMed

Roberts, James J; Fausch, Kurt D; Peterson, Douglas P; Hooten, Mevin B

2013-05-01

Impending changes in climate will interact with other stressors to threaten aquatic ecosystems and their biota. Native Colorado River cutthroat trout (CRCT; Oncorhynchus clarkii pleuriticus) are now relegated to 309 isolated high-elevation (>1700 m) headwater stream fragments in the Upper Colorado River Basin, owing to past nonnative trout invasions and habitat loss. Predicted changes in climate (i.e., temperature and precipitation) and resulting changes in stochastic physical disturbances (i.e., wildfire, debris flow, and channel drying and freezing) could further threaten the remaining CRCT populations. We developed an empirical model to predict stream temperatures at the fragment scale from downscaled climate projections along with geomorphic and landscape variables. We coupled these spatially explicit predictions of stream temperature with a Bayesian Network (BN) model that integrates stochastic risks from fragmentation to project persistence of CRCT populations across the upper Colorado River basin to 2040 and 2080. Overall, none of the populations are at risk from acute mortality resulting from high temperatures during the warmest summer period. In contrast, only 37% of populations have a ≥90% chance of persistence for 70 years (similar to the typical benchmark for conservation), primarily owing to fragmentation. Populations in short stream fragments <7 km long, and those at the lowest elevations, are at the highest risk of extirpation. Therefore, interactions of stochastic disturbances with fragmentation are projected to be greater threats than warming for CRCT populations. The reason for this paradox is that past nonnative trout invasions and habitat loss have restricted most CRCT populations to high-elevation stream fragments that are buffered from the potential consequences of warming, but at risk of extirpation from stochastic events. The greatest conservation need is for management to increase fragment lengths to forestall these risks. © 2013 Blackwell Publishing Ltd.

Fragmentation and thermal risks from climate change interact to affect persistence of native trout in the Colorado River basin

USGS Publications Warehouse

Roberts, James J.; Fausch, Kurt D.; Peterson, Douglas P.; Hooten, Mevin B.

2013-01-01

Impending changes in climate will interact with other stressors to threaten aquatic ecosystems and their biota. Native Colorado River cutthroat trout (CRCT; Oncorhynchus clarkii pleuriticus) are now relegated to 309 isolated high-elevation (>1700 m) headwater stream fragments in the Upper Colorado River Basin, owing to past nonnative trout invasions and habitat loss. Predicted changes in climate (i.e., temperature and precipitation) and resulting changes in stochastic physical disturbances (i.e., wildfire, debris flow, and channel drying and freezing) could further threaten the remaining CRCT populations. We developed an empirical model to predict stream temperatures at the fragment scale from downscaled climate projections along with geomorphic and landscape variables. We coupled these spatially explicit predictions of stream temperature with a Bayesian Network (BN) model that integrates stochastic risks from fragmentation to project persistence of CRCT populations across the upper Colorado River basin to 2040 and 2080. Overall, none of the populations are at risk from acute mortality resulting from high temperatures during the warmest summer period. In contrast, only 37% of populations have a greater than or equal to 90% chance of persistence for 70 years (similar to the typical benchmark for conservation), primarily owing to fragmentation. Populations in short stream fragments <7 km long, and those at the lowest elevations, are at the highest risk of extirpation. Therefore, interactions of stochastic disturbances with fragmentation are projected to be greater threats than warming for CRCT populations. The reason for this paradox is that past nonnative trout invasions and habitat loss have restricted most CRCT populations to high-elevation stream fragments that are buffered from the potential consequences of warming, but at risk of extirpation from stochastic events. The greatest conservation need is for management to increase fragment lengths to forestall these risks. 

[Comparison between administrative and clinical databases in the evaluation of cardiac surgery performance].

PubMed

Rosato, Stefano; D'Errigo, Paola; Badoni, Gabriella; Fusco, Danilo; Perucci, Carlo A; Seccareccia, Fulvia

2008-08-01

The availability of two contemporary sources of information about coronary artery bypass graft (CABG) interventions, allowed 1) to verify the feasibility of performing outcome evaluation studies using administrative data sources, and 2) to compare hospital performance obtainable using the CABG Project clinical database with hospital performance derived from the use of current administrative data. Interventions recorded in the CABG Project were linked to the hospital discharge record (HDR) administrative database. Only the linked records were considered for subsequent analyses (46% of the total CABG Project). A new selected population "clinical card-HDR" was then defined. Two independent risk-adjustment models were applied, each of them using information derived from one of the two different sources. Then, HDR information was supplemented with some patient preoperative conditions from the CABG clinical database. The two models were compared in terms of their adaptability to data. Hospital performances identified by the two different models and significantly different from the mean was compared. In only 4 of the 13 hospitals considered for analysis, the results obtained using the HDR model did not completely overlap with those obtained by the CABG model. When comparing statistical parameters of the HDR model and the HDR model + patient preoperative conditions, the latter showed the best adaptability to data. In this "clinical card-HDR" population, hospital performance assessment obtained using information from the clinical database is similar to that derived from the use of current administrative data. However, when risk-adjustment models built on administrative databases are supplemented with a few clinical variables, their statistical parameters improve and hospital performance assessment becomes more accurate.

Improving socioeconomic land use forecasting for medium-sized metropolitan organizations in Virginia.

DOT National Transportation Integrated Search

2008-01-01

Socioeconomic forecasts are the foundation for long range travel demand modeling, projecting variables such as population, households, employment, and vehicle ownership. In Virginia, metropolitan planning organizations (MPOs) develop socioeconomic fo...

Comparing estimates of child mortality reduction modelled in LiST with pregnancy history survey data for a community-based NGO project in Mozambique

PubMed Central

2011-01-01

Background There is a growing body of evidence that integrated packages of community-based interventions, a form of programming often implemented by NGOs, can have substantial child mortality impact. More countries may be able to meet Millennium Development Goal (MDG) 4 targets by leveraging such programming. Analysis of the mortality effect of this type of programming is hampered by the cost and complexity of direct mortality measurement. The Lives Saved Tool (LiST) produces an estimate of mortality reduction by modelling the mortality effect of changes in population coverage of individual child health interventions. However, few studies to date have compared the LiST estimates of mortality reduction with those produced by direct measurement. Methods Using results of a recent review of evidence for community-based child health programming, a search was conducted for NGO child health projects implementing community-based interventions that had independently verified child mortality reduction estimates, as well as population coverage data for modelling in LiST. One child survival project fit inclusion criteria. Subsequent searches of the USAID Development Experience Clearinghouse and Child Survival Grants databases and interviews of staff from NGOs identified no additional projects. Eight coverage indicators, covering all the project’s technical interventions were modelled in LiST, along with indicator values for most other non-project interventions in LiST, mainly from DHS data from 1997 and 2003. Results The project studied was implemented by World Relief from 1999 to 2003 in Gaza Province, Mozambique. An independent evaluation collecting pregnancy history data estimated that under-five mortality declined 37% and infant mortality 48%. Using project-collected coverage data, LiST produced estimates of 39% and 34% decline, respectively. Conclusions LiST gives reasonably accurate estimates of infant and child mortality decline in an area where a package of community-based interventions was implemented. This and other validation exercises support use of LiST as an aid for program planning to tailor packages of community-based interventions to the epidemiological context and for project evaluation. Such targeted planning and assessments will be useful to accelerate progress in reaching MDG4 targets. PMID:21501454

The potential impacts of 21st century climatic and population changes on human exposure to the virus vector mosquito Aedes aegypti.

PubMed

Monaghan, A J; Sampson, K M; Steinhoff, D F; Ernst, K C; Ebi, K L; Jones, B; Hayden, M H

2018-02-01

The mosquito Aedes (Ae). aegypti transmits the viruses that cause dengue and chikungunya, two globally-important vector-borne diseases. We investigate how choosing alternate emissions and/or socioeconomic pathways may modulate future human exposure to Ae. aegypti . Occurrence patterns for Ae. aegypti for 2061-2080 are mapped globally using empirically downscaled air temperature and precipitation projections from the Community Earth System Model, for the Representative Concentration Pathway (RCP) 4.5 and 8.5 scenarios. Population growth is quantified using gridded global population projections consistent with two Shared Socioeconomic Pathways (SSPs), SSP3 and SSP5. Change scenarios are compared to a 1950-2000 reference period. A global land area of 56.9 M km 2 is climatically suitable for Ae. aegypti during the reference period, and is projected to increase by 8% (RCP4.5) to 13% (RCP8.5) by 2061-2080. The annual average number of people exposed globally to Ae. aegypti for the reference period is 3794 M, a value projected to statistically significantly increase by 298-460 M (8-12%) by 2061-2080 if only climate change is considered, and by 4805-5084 M (127-134%) for SSP3 and 2232-2483 M (59-65%) for SSP5 considering both climate and population change (lower and upper values of each range represent RCP4.5 and RCP8.5 respectively). Thus, taking the lower-emissions RCP4.5 pathway instead of RCP8.5 may mitigate future human exposure to Ae. aegypti globally, but the effect of population growth on exposure will likely be larger. Regionally, Australia, Europe and North America are projected to have the largest percentage increases in human exposure to Ae. aegypti considering only climate change.

A History of Sandia’s Water Decision Modeling and Analysis Program

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lowry, Thomas Stephen; Pate, Ronald C.

This document provides a brief narrative, and selected project descriptions, that represent Sandia’s history involving data, modeling, and analysis related to water, energy-water nexus, and energy-water-agriculture nexus within the context of climate change. Sandia National Laboratories has been engaged since the early-1990s with program development involving data, modeling, and analysis projects that address the interdependent issues, risks, and technology-based mitigations associated with increasing demands and stresses being placed on energy, water, and agricultural/food resources, and the related impacts on their security and sustainability in the face of both domestic and global population growth, expanding economic development, and climate change.

Population growth of Yellowstone grizzly bears: Uncertainty and future monitoring

USGS Publications Warehouse

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 analysis.

Population models for passerine birds: structure, parameterization, and analysis

USGS Publications Warehouse

Noon, B.R.; Sauer, J.R.; McCullough, D.R.; Barrett, R.H.

1992-01-01

Population models have great potential as management tools, as they use infonnation about the life history of a species to summarize estimates of fecundity and survival into a description of population change. Models provide a framework for projecting future populations, determining the effects of management decisions on future population dynamics, evaluating extinction probabilities, and addressing a variety of questions of ecological and evolutionary interest. Even when insufficient information exists to allow complete identification of the model, the modelling procedure is useful because it forces the investigator to consider the life history of the species when determining what parameters should be estimated from field studies and provides a context for evaluating the relative importance of demographic parameters. Models have been little used in the study of the population dynamics of passerine birds because of: (1) widespread misunderstandings of the model structures and parameterizations, (2) a lack of knowledge of life histories of many species, (3) difficulties in obtaining statistically reliable estimates of demographic parameters for most passerine species, and (4) confusion about functional relationships among demographic parameters. As a result, studies of passerine demography are often designed inappropriately and fail to provide essential data. We review appropriate models for passerine bird populations and illustrate their possible uses in evaluating the effects of management or other environmental influences on population dynamics. We identify environmental influences on population dynamics. We identify parameters that must be estimated from field data, briefly review existing statistical methods for obtaining valid estimates, and evaluate the present status of knowledge of these parameters.

The effect of future ambient air pollution on human premature mortality to 2100 using output from the ACCMIP model ensemble

NASA Astrophysics Data System (ADS)

Silva, Raquel A.; West, J. Jason; Lamarque, Jean-François; Shindell, Drew T.; Collins, William J.; Dalsoren, Stig; Faluvegi, Greg; Folberth, Gerd; Horowitz, Larry W.; Nagashima, Tatsuya; Naik, Vaishali; Rumbold, Steven T.; Sudo, Kengo; Takemura, Toshihiko; Bergmann, Daniel; Cameron-Smith, Philip; Cionni, Irene; Doherty, Ruth M.; Eyring, Veronika; Josse, Beatrice; MacKenzie, Ian A.; Plummer, David; Righi, Mattia; Stevenson, David S.; Strode, Sarah; Szopa, Sophie; Zengast, Guang

2016-08-01

Ambient air pollution from ground-level ozone and fine particulate matter (PM2.5) is associated with premature mortality. Future concentrations of these air pollutants will be driven by natural and anthropogenic emissions and by climate change. Using anthropogenic and biomass burning emissions projected in the four Representative Concentration Pathway scenarios (RCPs), the ACCMIP ensemble of chemistry-climate models simulated future concentrations of ozone and PM2.5 at selected decades between 2000 and 2100. We use output from the ACCMIP ensemble, together with projections of future population and baseline mortality rates, to quantify the human premature mortality impacts of future ambient air pollution. Future air-pollution-related premature mortality in 2030, 2050 and 2100 is estimated for each scenario and for each model using a health impact function based on changes in concentrations of ozone and PM2.5 relative to 2000 and projected future population and baseline mortality rates. Additionally, the global mortality burden of ozone and PM2.5 in 2000 and each future period is estimated relative to 1850 concentrations, using present-day and future population and baseline mortality rates. The change in future ozone concentrations relative to 2000 is associated with excess global premature mortality in some scenarios/periods, particularly in RCP8.5 in 2100 (316 thousand deaths year-1), likely driven by the large increase in methane emissions and by the net effect of climate change projected in this scenario, but it leads to considerable avoided premature mortality for the three other RCPs. However, the global mortality burden of ozone markedly increases from 382 000 (121 000 to 728 000) deaths year-1 in 2000 to between 1.09 and 2.36 million deaths year-1 in 2100, across RCPs, mostly due to the effect of increases in population and baseline mortality rates. PM2.5 concentrations decrease relative to 2000 in all scenarios, due to projected reductions in emissions, and are associated with avoided premature mortality, particularly in 2100: between -2.39 and -1.31 million deaths year-1 for the four RCPs. The global mortality burden of PM2.5 is estimated to decrease from 1.70 (1.30 to 2.10) million deaths year-1 in 2000 to between 0.95 and 1.55 million deaths year-1 in 2100 for the four RCPs due to the combined effect of decreases in PM2.5 concentrations and changes in population and baseline mortality rates. Trends in future air-pollution-related mortality vary regionally across scenarios, reflecting assumptions for economic growth and air pollution control specific to each RCP and region. Mortality estimates differ among chemistry-climate models due to differences in simulated pollutant concentrations, which is the greatest contributor to overall mortality uncertainty for most cases assessed here, supporting the use of model ensembles to characterize uncertainty. Increases in exposed population and baseline mortality rates of respiratory diseases magnify the impact on premature mortality of changes in future air pollutant concentrations and explain why the future global mortality burden of air pollution can exceed the current burden, even where air pollutant concentrations decrease.

The effect of future ambient air pollution on human premature mortality to 2100 using output from the ACCMIP model ensemble.

PubMed

Silva, Raquel A; West, J Jason; Lamarque, Jean-François; Shindell, Drew T; Collins, William J; Dalsoren, Stig; Faluvegi, Greg; Folberth, Gerd; Horowitz, Larry W; Nagashima, Tatsuya; Naik, Vaishali; Rumbold, Steven T; Sudo, Kengo; Takemura, Toshihiko; Bergmann, Daniel; Cameron-Smith, Philip; Cionni, Irene; Doherty, Ruth M; Eyring, Veronika; Josse, Beatrice; MacKenzie, I A; Plummer, David; Righi, Mattia; Stevenson, David S; Strode, Sarah; Szopa, Sophie; Zeng, Guang

2016-01-01

Ambient air pollution from ground-level ozone and fine particulate matter (PM 2.5 ) is associated with premature mortality. Future concentrations of these air pollutants will be driven by natural and anthropogenic emissions and by climate change. Using anthropogenic and biomass burning emissions projected in the four Representative Concentration Pathway scenarios (RCPs), the ACCMIP ensemble of chemistry-climate models simulated future concentrations of ozone and PM 2.5 at selected decades between 2000 and 2100. We use output from the ACCMIP ensemble, together with projections of future population and baseline mortality rates, to quantify the human premature mortality impacts of future ambient air pollution. Future air pollution-related premature mortality in 2030, 2050 and 2100 is estimated for each scenario and for each model using a health impact function based on changes in concentrations of ozone and PM 2.5 relative to 2000 and projected future population and baseline mortality rates. Additionally, the global mortality burden of ozone and PM 2.5 in 2000 and each future period is estimated relative to 1850 concentrations, using present-day and future population and baseline mortality rates. The change in future ozone concentrations relative to 2000 is associated with excess global premature mortality in some scenarios/periods, particularly in RCP8.5 in 2100 (316 thousand deaths/year), likely driven by the large increase in methane emissions and by the net effect of climate change projected in this scenario, but it leads to considerable avoided premature mortality for the three other RCPs. However, the global mortality burden of ozone markedly increases from 382,000 (121,000 to 728,000) deaths/year in 2000 to between 1.09 and 2.36 million deaths/year in 2100, across RCPs, mostly due to the effect of increases in population and baseline mortality rates. PM 2.5 concentrations decrease relative to 2000 in all scenarios, due to projected reductions in emissions, and are associated with avoided premature mortality, particularly in 2100: between -2.39 and -1.31 million deaths/year for the four RCPs. The global mortality burden of PM 2.5 is estimated to decrease from 1.70 (1.30 to 2.10) million deaths/year in 2000 to between 0.95 and 1.55 million deaths/year in 2100 for the four RCPs, due to the combined effect of decreases in PM 2.5 concentrations and changes in population and baseline mortality rates. Trends in future air pollution-related mortality vary regionally across scenarios, reflecting assumptions for economic growth and air pollution control specific to each RCP and region. Mortality estimates differ among chemistry-climate models due to differences in simulated pollutant concentrations, which is the greatest contributor to overall mortality uncertainty for most cases assessed here, supporting the use of model ensembles to characterize uncertainty. Increases in exposed population and baseline mortality rates of respiratory diseases magnify the impact on premature mortality of changes in future air pollutant concentrations and explain why the future global mortality burden of air pollution can exceed the current burden, even where air pollutant concentrations decrease.

Health Impacts of Increased Physical Activity from Changes in Transportation Infrastructure: Quantitative Estimates for Three Communities

PubMed Central

2015-01-01

Recently, two quantitative tools have emerged for predicting the health impacts of projects that change population physical activity: the Health Economic Assessment Tool (HEAT) and Dynamic Modeling for Health Impact Assessment (DYNAMO-HIA). HEAT has been used to support health impact assessments of transportation infrastructure projects, but DYNAMO-HIA has not been previously employed for this purpose nor have the two tools been compared. To demonstrate the use of DYNAMO-HIA for supporting health impact assessments of transportation infrastructure projects, we employed the model in three communities (urban, suburban, and rural) in North Carolina. We also compared DYNAMO-HIA and HEAT predictions in the urban community. Using DYNAMO-HIA, we estimated benefit-cost ratios of 20.2 (95% C.I.: 8.7–30.6), 0.6 (0.3–0.9), and 4.7 (2.1–7.1) for the urban, suburban, and rural projects, respectively. For a 40-year time period, the HEAT predictions of deaths avoided by the urban infrastructure project were three times as high as DYNAMO-HIA's predictions due to HEAT's inability to account for changing population health characteristics over time. Quantitative health impact assessment coupled with economic valuation is a powerful tool for integrating health considerations into transportation decision-making. However, to avoid overestimating benefits, such quantitative HIAs should use dynamic, rather than static, approaches. PMID:26504832

Health Impacts of Increased Physical Activity from Changes in Transportation Infrastructure: Quantitative Estimates for Three Communities.

PubMed

Mansfield, Theodore J; MacDonald Gibson, Jacqueline

2015-01-01

Recently, two quantitative tools have emerged for predicting the health impacts of projects that change population physical activity: the Health Economic Assessment Tool (HEAT) and Dynamic Modeling for Health Impact Assessment (DYNAMO-HIA). HEAT has been used to support health impact assessments of transportation infrastructure projects, but DYNAMO-HIA has not been previously employed for this purpose nor have the two tools been compared. To demonstrate the use of DYNAMO-HIA for supporting health impact assessments of transportation infrastructure projects, we employed the model in three communities (urban, suburban, and rural) in North Carolina. We also compared DYNAMO-HIA and HEAT predictions in the urban community. Using DYNAMO-HIA, we estimated benefit-cost ratios of 20.2 (95% C.I.: 8.7-30.6), 0.6 (0.3-0.9), and 4.7 (2.1-7.1) for the urban, suburban, and rural projects, respectively. For a 40-year time period, the HEAT predictions of deaths avoided by the urban infrastructure project were three times as high as DYNAMO-HIA's predictions due to HEAT's inability to account for changing population health characteristics over time. Quantitative health impact assessment coupled with economic valuation is a powerful tool for integrating health considerations into transportation decision-making. However, to avoid overestimating benefits, such quantitative HIAs should use dynamic, rather than static, approaches.

Cholera epidemic in Haiti, 2010: using a transmission model to explain spatial spread of disease and identify optimal control interventions.

PubMed

Tuite, Ashleigh R; Tien, Joseph; Eisenberg, Marisa; Earn, David J D; Ma, Junling; Fisman, David N

2011-05-03

Haiti is in the midst of a cholera epidemic. Surveillance data for formulating models of the epidemic are limited, but such models can aid understanding of epidemic processes and help define control strategies. To predict, by using a mathematical model, the sequence and timing of regional cholera epidemics in Haiti and explore the potential effects of disease-control strategies. Compartmental mathematical model allowing person-to-person and waterborne transmission of cholera. Within- and between-region epidemic spread was modeled, with the latter dependent on population sizes and distance between regional centroids (a "gravity" model). Haiti, 2010 to 2011. Haitian hospitalization data, 2009 census data, literature-derived parameter values, and model calibration. Dates of epidemic onset and hospitalizations. The plausible range for cholera's basic reproductive number (R(0), defined as the number of secondary cases per primary case in a susceptible population without intervention) was 2.06 to 2.78. The order and timing of regional cholera outbreaks predicted by the gravity model were closely correlated with empirical observations. Analysis of changes in disease dynamics over time suggests that public health interventions have substantially affected this epidemic. A limited vaccine supply provided late in the epidemic was projected to have a modest effect. Assumptions were simplified, which was necessary for modeling. Projections are based on the initial dynamics of the epidemic, which may change. Despite limited surveillance data from the cholera epidemic in Haiti, a model simulating between-region disease transmission according to population and distance closely reproduces reported disease patterns. This model is a tool that planners, policymakers, and medical personnel seeking to manage the epidemic could use immediately.

Targeted and Non-Targeted Analysis of Serum Pools to Provide Chemical Exposure Data for Exposure Modeling and Chemical Prioritization

EPA Science Inventory

Biomonitoring data can help inform the development and calibration of high-throughput exposure modeling for use in prioritization and risk evaluation. A pilot project was conducted to evaluate the feasibility of using pooled banked blood samples to generate initial data on popul...

75 FR 51242 - Fisheries of the South Atlantic; Southeast Data, Assessment, and Review (SEDAR); Public Meeting

Federal Register 2010, 2011, 2012, 2013, 2014

2010-08-19

... benchmarks, projects future population conditions, and recommends research and monitoring needs. Participants....--4 p.m. Assessment panelists will discuss data inputs to the stock assessment model and make recommendations for additional years of data to be updated in the model. New information on black sea bass life...

MULTIREGION: a simulation-forecasting model of BEA economic area population and employment. [Bureau of Economic Analysis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Olsen, R.J.; Westley, G.W.; Herzog, H.W. Jr.

This report documents the development of MULTIREGION, a computer model of regional and interregional socio-economic development. The MULTIREGION model interprets the economy of each BEA economic area as a labor market, measures all activity in terms of people as members of the population (labor supply) or as employees (labor demand), and simultaneously simulates or forecasts the demands and supplies of labor in all BEA economic areas at five-year intervals. In general the outputs of MULTIREGION are intended to resemble those of the Water Resource Council's OBERS projections and to be put to similar planning and analysis purposes. This report hasmore » been written at two levels to serve the needs of multiple audiences. The body of the report serves as a fairly nontechnical overview of the entire MULTIREGION project; a series of technical appendixes provide detailed descriptions of the background empirical studies of births, deaths, migration, labor force participation, natural resource employment, manufacturing employment location, and local service employment used to construct the model.« less

[Fishery resource protection by artificial propagation in hydroelectric development: Lixianjiang River drainage in Yunnan as an example].

PubMed

Yang, Yong-Hong; Yang, Jun-Xing; Pan, Xiao-Fu; Zhou, Wei; Yang, Mei-Lin

2011-04-01

Hydroelectric developments can result in a number of negative environmental consequences. Conservation aquaculture is a branch of science derived from conservation and population recovery studies on endangered fishes. Here we discuss the impacts on fishes caused by hydropower projects in Lixianjiang, and evaluate effects and problems on the propagation of Parazacco spilurus, Hemibagrus pluriradiatus, Neolissochilus benasi and Semilabeo obscurus. A successful propagation project includes foraging ecology in fields, pond cultivation, juvenile fish raising, prevention and curing on fish disease, genetic management, artificial releasing and population monitoring. Artificial propagation is the practicable act on genetic intercommunication, preventing population deterioration for fishes in upper and lower reaches of the dam. For long-term planning, fish stocks are not suitable for many kind of fishes, but can prevent fishes from going extinct in the wild. Basic data collection on fish ecology, parent fish hunting, prevention on fish disease are the most important factors on artificial propagation. Strengthening the genetic management of stock population for keeping a higher genetic diversity can increase the success of stock enhancement. The works on Lixianjiang provide a new model for river fish protection. To make sure the complicated project works well, project plans, commission contracts, base line monitoring and techniques on artificial reproduction must be considered early. Last, fishery conservation should be considered alongside location development.

Tuning stochastic matrix models with hydrologic data to predict the population dynamics of a riverine fish.

PubMed

Sakaris, Peter C; Irwin, Elise R

2010-03-01

We developed stochastic matrix models to evaluate the effects of hydrologic alteration and variable mortality on the population dynamics of a lotic fish in a regulated river system. Models were applied to a representative lotic fish species, the flathead catfish (Pylodictis olivaris), for which two populations were examined: a native population from a regulated reach of the Coosa River (Alabama, USA) and an introduced population from an unregulated section of the Ocmulgee River (Georgia, USA). Size-classified matrix models were constructed for both populations, and residuals from catch-curve regressions were used as indices of year class strength (i.e., recruitment). A multiple regression model indicated that recruitment of flathead catfish in the Coosa River was positively related to the frequency of spring pulses between 283 and 566 m3/s. For the Ocmulgee River population, multiple regression models indicated that year class strength was negatively related to mean March discharge and positively related to June low flow. When the Coosa population was modeled to experience five consecutive years of favorable hydrologic conditions during a 50-year projection period, it exhibited a substantial spike in size and increased at an overall 0.2% annual rate. When modeled to experience five years of unfavorable hydrologic conditions, the Coosa population initially exhibited a decrease in size but later stabilized and increased at a 0.4% annual rate following the decline. When the Ocmulgee River population was modeled to experience five years of favorable conditions, it exhibited a substantial spike in size and increased at an overall 0.4% annual rate. After the Ocmulgee population experienced five years of unfavorable conditions, a sharp decline in population size was predicted. However, the population quickly recovered, with population size increasing at a 0.3% annual rate following the decline. In general, stochastic population growth in the Ocmulgee River was more erratic and variable than population growth in the Coosa River. We encourage ecologists to develop similar models for other lotic species, particularly in regulated river systems. Successful management of fish populations in regulated systems requires that we are able to predict how hydrology affects recruitment and will ultimately influence the population dynamics of fishes.

1980 ASEAN programme roundup: a model in the making.

PubMed

1981-01-01

Association of Southeast Asian Nations (ASEAN) experts and heads of national population programs held their 4th meeting in Singapore from November 24-28, 1980. Program heads resolved to take steps to link their national activities in the population field with those of the ASEAN Population Program and carry out studies and a joint programming exercise in 1981. Progress reports on the following Phase 1 projects were given: 1) integration of population and rural development policies and programs in ASEAN countries including Indonesia, Malaysia, Philippines, Singapore, and Thailand; 2) development of an inter-country modular training program for personnel in population and rural development; 3) multi-media support for population programs in the context of rural development in ASEAN countries; 4) utilization of research findings in population and family planning for policy formulation and program management in ASEAN countries; and 5) migration in relation to rural development. Phase 2 projects approved by ASEAN country participants were also discussed: 1) institutional development and exchange of personnel, 2) women in development, 3) developing and strengthening national population information systems and networks in ASEAN countries, 4) population and development dynamics and the man/resource balance, 5) studies on health and family planning in ASEAN countries, 6) population migration movement and development, and 7) development of ASEAN social indicators.

The human core of the shared socioeconomic pathways: Population scenarios by age, sex and level of education for all countries to 2100.

PubMed

Kc, Samir; Lutz, Wolfgang

2017-01-01

This paper applies the methods of multi-dimensional mathematical demography to project national populations based on alternative assumptions on future, fertility, mortality, migration and educational transitions that correspond to the five shared socioeconomic pathways (SSP) storylines. In doing so it goes a significant step beyond past population scenarios in the IPCC context which considered only total population size. By differentiating the human population not only by age and sex-as is conventionally done in demographic projections-but also by different levels of educational attainment the most fundamental aspects of human development and social change are being explicitly addressed through modeling the changing composition of populations by these three important individual characteristics. The scenarios have been defined in a collaborative effort of the international Integrated Assessment Modeling community with the medium scenario following that of a major new effort by the Wittgenstein Centre for Demography and Global Human Capital (IIASA, OEAW, WU) involving over 550 experts from around the world. As a result, in terms of total world population size the trajectories resulting from the five SSPs stay very close to each other until around 2030 and by the middle of the century already a visible differentiation appears with the range between the highest (SSP3) and the lowest (SSP1) trajectories spanning 1.5 billion. The range opens up much more with the SSP3 reaching 12.6 billion in 2100 and SSP1 falling to 6.9 billion which is lower than today's world population.

Cost-Savings to Medicare From Pre-Medicare Colorectal Cancer Screening.

PubMed

Goede, Simon L; Kuntz, Karen M; van Ballegooijen, Marjolein; Knudsen, Amy B; Lansdorp-Vogelaar, Iris; Tangka, Florence K; Howard, David H; Chin, Joseph; Zauber, Ann G; Seeff, Laura C

2015-07-01

Many individuals have not received recommended colorectal cancer (CRC) screening before they become Medicare eligible at the age of 65. We aimed to estimate the long-term implications of increased CRC screening in the pre-Medicare population (50-64 y) on costs in the pre-Medicare and Medicare populations (65+ y). We used 2 independently developed microsimulation models [Microsimulation Screening Analysis Colon (MISCAN) and Simulation Model of CRC (SimCRC)] to project CRC screening and treatment costs under 2 scenarios, starting in 2010: "current trends" (60% of the population up-to-date with screening recommendations) and "enhanced participation" (70% up-to-date). The population was scaled to the projected US population for each year between 2010 and 2060. Costs per year were derived by age group (50-64 and 65+ y). By 2060, the discounted cumulative total costs in the pre-Medicare population were $35.7 and $28.1 billion higher with enhanced screening participation, than in the current trends scenario ($252.1 billion with MISCAN and $239.5 billion with SimCRC, respectively). Because of CRC treatment savings with enhanced participation, cumulative costs in the Medicare population were $18.3 and $32.7 billion lower (current trends: $423.5 billion with MISCAN and $372.8 billion with SimCRC). Over the 50-year time horizon an estimated 60% (MISCAN) and 89% (SimCRC) of the increased screening costs could be offset by savings in Medicare CRC treatment costs. Increased CRC screening participation in the pre-Medicare population could reduce CRC incidence and mortality, whereas the additional screening costs can be largely offset by long-term Medicare treatment savings.

Developing a Resource for Implementing ArcSWAT Using Global Datasets

NASA Astrophysics Data System (ADS)

Taggart, M.; Caraballo Álvarez, I. O.; Mueller, C.; Palacios, S. L.; Schmidt, C.; Milesi, C.; Palmer-Moloney, L. J.

2015-12-01

This project developed a comprehensive user manual outlining methods for adapting and implementing global datasets for use within ArcSWAT for international and worldwide applications. The Soil and Water Assessment Tool (SWAT) is a hydrologic model that looks at a number of hydrologic variables including runoff and the chemical makeup of water at a given location on the Earth's surface using Digital Elevation Models (DEM), land cover, soil, and weather data. However, the application of ArcSWAT for projects outside of the United States is challenging as there is no standard framework for inputting global datasets into ArcSWAT. This project aims to remove this obstacle by outlining methods for adapting and implementing these global datasets via the user manual. The manual takes the user through the processes of data conditioning while providing solutions and suggestions for common errors. The efficacy of the manual was explored using examples from watersheds located in Puerto Rico, Mexico and Western Africa. Each run explored the various options for setting up a ArcSWAT project as well as a range of satellite data products and soil databases. Future work will incorporate in-situ data for validation and calibration of the model and outline additional resources to assist future users in efficiently implementing the model for worldwide applications. The capacity to manage and monitor freshwater availability is of critical importance in both developed and developing countries. As populations grow and climate changes, both the quality and quantity of freshwater are affected resulting in negative impacts on the health of the surrounding population. The use of hydrologic models such as ArcSWAT can help stakeholders and decision makers understand the future impacts of these changes enabling informed and substantiated decisions.

Challenges and Opportunities in Disease Forecasting in Outbreak Settings: A Case Study of Measles in Lola Prefecture, Guinea

PubMed Central

Graham, Matthew; Suk, Jonathan E.; Takahashi, Saki; Metcalf, C. Jessica; Jimenez, A. Paez; Prikazsky, Vladimir; Ferrari, Matthew J.; Lessler, Justin

2018-01-01

Abstract. We report on and evaluate the process and findings of a real-time modeling exercise in response to an outbreak of measles in Lola prefecture, Guinea, in early 2015 in the wake of the Ebola crisis. Multiple statistical methods for the estimation of the size of the susceptible (i.e., unvaccinated) population were applied to weekly reported measles case data on seven subprefectures throughout Lola. Stochastic compartmental models were used to project future measles incidence in each subprefecture in both an initial and a follow-up iteration of forecasting. Measles susceptibility among 1- to 5-year-olds was estimated to be between 24% and 43% at the beginning of the outbreak. Based on this high baseline susceptibility, initial projections forecasted a large outbreak occurring over approximately 10 weeks and infecting 40 children per 1,000. Subsequent forecasts based on updated data mitigated this initial projection, but still predicted a significant outbreak. A catch-up vaccination campaign took place at the same time as this second forecast and measles cases quickly receded. Of note, case reports used to fit models changed significantly between forecast rounds. Model-based projections of both current population risk and future incidence can help in setting priorities and planning during an outbreak response. A swiftly changing situation on the ground, coupled with data uncertainties and the need to adjust standard analytical approaches to deal with sparse data, presents significant challenges. Appropriate presentation of results as planning scenarios, as well as presentations of uncertainty and two-way communication, is essential to the effective use of modeling studies in outbreak response. PMID:29532773

Challenges and Opportunities in Disease Forecasting in Outbreak Settings: A Case Study of Measles in Lola Prefecture, Guinea.

PubMed

Graham, Matthew; Suk, Jonathan E; Takahashi, Saki; Metcalf, C Jessica; Jimenez, A Paez; Prikazsky, Vladimir; Ferrari, Matthew J; Lessler, Justin

2018-05-01

We report on and evaluate the process and findings of a real-time modeling exercise in response to an outbreak of measles in Lola prefecture, Guinea, in early 2015 in the wake of the Ebola crisis. Multiple statistical methods for the estimation of the size of the susceptible (i.e., unvaccinated) population were applied to weekly reported measles case data on seven subprefectures throughout Lola. Stochastic compartmental models were used to project future measles incidence in each subprefecture in both an initial and a follow-up iteration of forecasting. Measles susceptibility among 1- to 5-year-olds was estimated to be between 24% and 43% at the beginning of the outbreak. Based on this high baseline susceptibility, initial projections forecasted a large outbreak occurring over approximately 10 weeks and infecting 40 children per 1,000. Subsequent forecasts based on updated data mitigated this initial projection, but still predicted a significant outbreak. A catch-up vaccination campaign took place at the same time as this second forecast and measles cases quickly receded. Of note, case reports used to fit models changed significantly between forecast rounds. Model-based projections of both current population risk and future incidence can help in setting priorities and planning during an outbreak response. A swiftly changing situation on the ground, coupled with data uncertainties and the need to adjust standard analytical approaches to deal with sparse data, presents significant challenges. Appropriate presentation of results as planning scenarios, as well as presentations of uncertainty and two-way communication, is essential to the effective use of modeling studies in outbreak response.

Population Accessibility to Radiotherapy Services in New South Wales Region of Australia: a methodological contribution

NASA Astrophysics Data System (ADS)

Shukla, Nagesh; Wickramasuriya, Rohan; Miller, Andrew; Perez, Pascal

2015-05-01

This paper proposes an integrated modelling process to assess the population accessibility to radiotherapy treatment services in future based on future cancer incidence and road network-based accessibility. Previous research efforts assessed travel distance/time barriers affecting access to cancer treatment services, as well as epidemiological studies that showed that cancer incidence rates vary with population demography. It is established that travel distances to treatment centres and demographic profiles of the accessible regions greatly influence the demand for cancer radiotherapy (RT) services. However, an integrated service planning approach that combines spatially-explicit cancer incidence projections, and the RT services accessibility based on patient road network have never been attempted. This research work presents this novel methodology for the accessibility assessment of RT services and demonstrates its viability by modelling New South Wales (NSW) cancer incidence rates for different age-sex groups based on observed cancer incidence trends; estimating the road network-based access to current NSW treatment centres; and, projecting the demand for RT services in New South Wales, Australia from year 2011 to 2026.

Revised Baseline Budget Projections for Fiscal Years 1999-2008

DTIC Science & Technology

1998-03-03

or for the conclusions that CBO reached. CONTENTS SUMMARY AND INTRODUCTION 1 MODELING THE ECONOMY 3 Production 6 Private Capital and Labor 7... modeling the economy and the federal budget in the long run and to estimating the effects of uncertainty about future population and productivity . MODELING ...conventions of the official national income and product accounts (NIPAs). Given the equations, the model needs two other factors to make a simulation

Detecting past changes of effective population size

PubMed Central

Nikolic, Natacha; Chevalet, Claude

2014-01-01

Understanding and predicting population abundance is a major challenge confronting scientists. Several genetic models have been developed using microsatellite markers to estimate the present and ancestral effective population sizes. However, to get an overview on the evolution of population requires that past fluctuation of population size be traceable. To address the question, we developed a new model estimating the past changes of effective population size from microsatellite by resolving coalescence theory and using approximate likelihoods in a Monte Carlo Markov Chain approach. The efficiency of the model and its sensitivity to gene flow and to assumptions on the mutational process were checked using simulated data and analysis. The model was found especially useful to provide evidence of transient changes of population size in the past. The times at which some past demographic events cannot be detected because they are too ancient and the risk that gene flow may suggest the false detection of a bottleneck are discussed considering the distribution of coalescence times. The method was applied on real data sets from several Atlantic salmon populations. The method called VarEff (Variation of Effective size) was implemented in the R package VarEff and is made available at https://qgsp.jouy.inra.fr and at http://cran.r-project.org/web/packages/VarEff. PMID:25067949

Mainstreaming Modeling and Simulation to Accelerate Public Health Innovation

PubMed Central

Sepulveda, Martin-J.; Mabry, Patricia L.

2014-01-01

Dynamic modeling and simulation are systems science tools that examine behaviors and outcomes resulting from interactions among multiple system components over time. Although there are excellent examples of their application, they have not been adopted as mainstream tools in population health planning and policymaking. Impediments to their use include the legacy and ease of use of statistical approaches that produce estimates with confidence intervals, the difficulty of multidisciplinary collaboration for modeling and simulation, systems scientists’ inability to communicate effectively the added value of the tools, and low funding for population health systems science. Proposed remedies include aggregation of diverse data sets, systems science training for public health and other health professionals, changing research incentives toward collaboration, and increased funding for population health systems science projects. PMID:24832426

Assessing the Impacts of Climate and Land Use Change on Streamflow and Nutrient Loading in the Arroyo Colorado Watershed in Southern Texas

NASA Astrophysics Data System (ADS)

Osidele, O.; Sun, A.; Green, R.

2011-12-01

Based on results of the Second National Climate Assessment reported in 2009, the U.S. Global Change Research Program projects temperatures in southern Texas will increase 5 to 8° F by the end of the 21st century, with larger changes occurring under scenarios of higher greenhouse gas emissions. Temperature increases in summer are projected to be larger than in winter. Although drier conditions are expected in the region, sea-level rise, extreme rainfall events, and associated storm surges are projected to occur more frequently because of the likely increase in intensity of hurricanes and tropical storms in the Gulf of Mexico. The range of possible responses to climate change is attributable to a combination of characteristics at global, regional, and local scales. The risk of flooding and catastrophic infrastructure damage due to global climate phenomena has been incorporated into local climate adaptation plans for many low-lying areas and communities in the Gulf Coast region of southern Texas. However, because this region is dominated by irrigated agriculture and the population is projected to double by 2050, it is important to examine how climate change will affect water resources and environmental quality. The purpose of this study is to investigate the potential hydrologic and water quality impacts of projected climate change, land use change, and population change scenarios in the headwaters of the Arroyo Colorado. The results of this work will provide content for a web-based, collaborative geospatial decision support system being developed to support environmental management in the Arroyo Colorado Watershed. Presently, land use in the Arroyo Colorado Watershed is more than 50 percent agricultural and almost 25 percent residential with varying levels of urbanization. As a result, flow in the Arroyo Colorado is sustained primarily by discharge from municipal wastewater treatment facilities, irrigation return flows, and urban storm runoff. In this study, streamflow and nutrient loading simulations for the Arroyo Colorado Watershed are based on the application of the Soil and Water Assessment Tool (SWAT) model driven by projected future climatic conditions generated from five global circulation models under three greenhouse gas emission scenarios. Land use change data are incorporated based on various remote sensing earth observation products including NASA's Moderate Resolution Imaging Spectroradiometer datasets and Landsat images in the multiagency National Land Cover Database. Population change and urbanization are considered in terms of changes in permitted wastewater treatment discharges. The findings of this study indicate that hydrological models like SWAT are useful tools for evaluating the watershed impacts from global climate change scenarios. In developing climate adaption plans, such models should include significant interactions among various local water management systems driven by population growth and urbanization in communities, and site-specific agricultural water use.

Addressing potential local adaptation in species distribution models: implications for conservation under climate change

USGS Publications Warehouse

Hällfors, Maria Helena; Liao, Jishan; Dzurisin, Jason D. K.; Grundel, Ralph; Hyvärinen, Marko; Towle, Kevin; Wu, Grace C.; Hellmann, Jessica J.

2016-01-01

Species distribution models (SDMs) have been criticized for involving assumptions that ignore or categorize many ecologically relevant factors such as dispersal ability and biotic interactions. Another potential source of model error is the assumption that species are ecologically uniform in their climatic tolerances across their range. Typically, SDMs to treat a species as a single entity, although populations of many species differ due to local adaptation or other genetic differentiation. Not taking local adaptation into account, may lead to incorrect range prediction and therefore misplaced conservation efforts. A constraint is that we often do not know the degree to which populations are locally adapted, however. Lacking experimental evidence, we still can evaluate niche differentiation within a species' range to promote better conservation decisions. We explore possible conservation implications of making type I or type II errors in this context. For each of two species, we construct three separate MaxEnt models, one considering the species as a single population and two of disjunct populations. PCA analyses and response curves indicate different climate characteristics in the current environments of the populations. Model projections into future climates indicate minimal overlap between areas predicted to be climatically suitable by the whole species versus population-based models. We present a workflow for addressing uncertainty surrounding local adaptation in SDM application and illustrate the value of conducting population-based models to compare with whole-species models. These comparisons might result in more cautious management actions when alternative range outcomes are considered.

Future requirements for and supply of ophthalmologists for an aging population in Singapore.

PubMed

Ansah, John P; De Korne, Dirk; Bayer, Steffen; Pan, Chong; Jayabaskar, Thiyagarajan; Matchar, David B; Lew, Nicola; Phua, Andrew; Koh, Victoria; Lamoureux, Ecosse; Quek, Desmond

2015-11-17

Singapore's population, as that of many other countries, is aging; this is likely to lead to an increase in eye diseases and the demand for eye care. Since ophthalmologist training is long and expensive, early planning is essential. This paper forecasts workforce and training requirements for Singapore up to the year 2040 under several plausible future scenarios. The Singapore Eye Care Workforce Model was created as a continuous time compartment model with explicit workforce stocks using system dynamics. The model has three modules: prevalence of eye disease, demand, and workforce requirements. The model is used to simulate the prevalence of eye diseases, patient visits, and workforce requirements for the public sector under different scenarios in order to determine training requirements. Four scenarios were constructed. Under the baseline business-as-usual scenario, the required number of ophthalmologists is projected to increase by 117% from 2015 to 2040. Under the current policy scenario (assuming an increase of service uptake due to increased awareness, availability, and accessibility of eye care services), the increase will be 175%, while under the new model of care scenario (considering the additional effect of providing some services by non-ophthalmologists) the increase will only be 150%. The moderated workload scenario (assuming in addition a reduction of the clinical workload) projects an increase in the required number of ophthalmologists of 192% by 2040. Considering the uncertainties in the projected demand for eye care services, under the business-as-usual scenario, a residency intake of 8-22 residents per year is required, 17-21 under the current policy scenario, 14-18 under the new model of care scenario, and, under the moderated workload scenario, an intake of 18-23 residents per year is required. The results show that under all scenarios considered, Singapore's aging and growing population will result in an almost doubling of the number of Singaporeans with eye conditions, a significant increase in public sector eye care demand and, consequently, a greater requirement for ophthalmologists.

Terrestrial population models for ecological risk assessment: A state-of-the-art review

USGS Publications Warehouse

Emlen, J.M.

1989-01-01

Few attempts have been made to formulate models for predicting impacts of xenobiotic chemicals on wildlife populations. However, considerable effort has been invested in wildlife optimal exploitation models. Because death from intoxication has a similar effect on population dynamics as death by harvesting, these management models are applicable to ecological risk assessment. An underlying Leslie-matrix bookkeeping formulation is widely applicable to vertebrate wildlife populations. Unfortunately, however, the various submodels that track birth, death, and dispersal rates as functions of the physical, chemical, and biotic environment are by their nature almost inevitably highly species- and locale-specific. Short-term prediction of one-time chemical applications requires only information on mortality before and after contamination. In such cases a simple matrix formulation may be adequate for risk assessment. But generally, risk must be projected over periods of a generation or more. This precludes generic protocols for risk assessment and also the ready and inexpensive predictions of a chemical's influence on a given population. When designing and applying models for ecological risk assessment at the population level, the endpoints (output) of concern must be carefully and rigorously defined. The most easily accessible and appropriate endpoints are (1) pseudoextinction (the frequency or probability of a population falling below a prespecified density), and (2) temporal mean population density. Spatial and temporal extent of predicted changes must be clearly specified a priori to avoid apparent contradictions and confusion.

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

PubMed

Schwindt, Adam R; Winkelman, Dana L

2016-09-01

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.

Shortage of cardiothoracic surgeons is likely by 2020.

PubMed

Grover, Atul; Gorman, Karyn; Dall, Timothy M; Jonas, Richard; Lytle, Bruce; Shemin, Richard; Wood, Douglas; Kron, Irving

2009-08-11

Even as the burden of cardiovascular disease in the United States is increasing as the population grows and ages, the number of active cardiothoracic surgeons has fallen for the first time in 20 years. Meanwhile, the treatment of patients with coronary artery disease continues to evolve amid uncertain changes in technology. This study evaluates current and future requirements for cardiothoracic surgeons in light of decreasing rates of coronary artery bypass grafting procedures. Projections of supply and demand for cardiothoracic surgeons are based on analysis of population, physician office, hospital, and physician data sets to estimate current patterns of healthcare use and delivery. Using a simulation model, we project the future supply of cardiothoracic surgeons under alternative assumptions about the number of new fellows trained each year. Future demand is modeled, taking into account patient demographics, under current and alternative use rates that include the elimination of open revascularization. By 2025, the demand for cardiothoracic surgeons could increase by 46% on the basis of population growth and aging if current healthcare use and service delivery patterns continue. Even with complete elimination of coronary artery bypass grafting, there is a projected shortfall of cardiothoracic surgeons because the active supply is projected to decrease 21% over the same time period as a result of retirement and declining entrants. The United States is facing a shortage of cardiothoracic surgeons within the next 10 years, which could diminish quality of care if non-board-certified physicians expand their role in cardiothoracic surgery or if patients must delay appropriate care because of a shortage of well-trained surgeons.

Impact of Climate Change on Heat-Related Mortality in Jiangsu Province, China

NASA Technical Reports Server (NTRS)

Chen, Kai; Horton, Radley M.; Bader, Daniel A.; Lesk, Corey; Jiang, Leiwen; Jones, Bryan; Zhou, Lian; Chen, Xiaodong; Bi, Jun; Kinney, Patrick L.

2017-01-01

A warming climate is anticipated to increase the future heat-related total mortality in urban areas. However, little evidence has been reported for cause-specific mortality or nonurban areas. Here we assessed the impact of climate change on heat-related total and cause-specific mortality in both urban and rural counties of Jiangsu Province, China, in the next five decades. To address the potential uncertainty in projecting future heat-related mortality, we applied localized urban- and nonurban-specific exposure response functions, six population projections including a no population change scenario and five Shared Socioeconomic Pathways (SSPs), and 42 temperature projections from 21 global-scale general circulation models and two Representative Concentration Pathways (RCPs). Results showed that projected warmer temperatures in 2016-2040 and 2041-2065 will lead to higher heat-related mortality for total non-accidental, cardiovascular, respiratory, stroke, ischemic heart disease (IHD), and chronic obstructive pulmonary disease (COPD) causes occurring annually during May to September in Jiangsu Province, China. Nonurban residents in Jiangsu will suffer from more excess heat-related cause-specific mortality in 2016-2065 than urban residents. Variations across climate models and RCPs dominated the uncertainty of heat-related mortality estimation whereas population size change only had limited influence. Our findings suggest that targeted climate change mitigation and adaptation measures should be taken in both urban and nonurban areas of Jiangsu Province. Specific public health interventions should be focused on the leading causes of death (stroke, IHD, and COPD), whose health burden will be amplified by a warming climate.

Impact of climate change on heat-related mortality in Jiangsu Province, China.

PubMed

Chen, Kai; Horton, Radley M; Bader, Daniel A; Lesk, Corey; Jiang, Leiwen; Jones, Bryan; Zhou, Lian; Chen, Xiaodong; Bi, Jun; Kinney, Patrick L

2017-05-01

A warming climate is anticipated to increase the future heat-related total mortality in urban areas. However, little evidence has been reported for cause-specific mortality or nonurban areas. Here we assessed the impact of climate change on heat-related total and cause-specific mortality in both urban and rural counties of Jiangsu Province, China, in the next five decades. To address the potential uncertainty in projecting future heat-related mortality, we applied localized urban- and nonurban-specific exposure response functions, six population projections including a no population change scenario and five Shared Socioeconomic Pathways (SSPs), and 42 temperature projections from 21 global-scale general circulation models and two Representative Concentration Pathways (RCPs). Results showed that projected warmer temperatures in 2016-2040 and 2041-2065 will lead to higher heat-related mortality for total non-accidental, cardiovascular, respiratory, stroke, ischemic heart disease (IHD), and chronic obstructive pulmonary disease (COPD) causes occurring annually during May to September in Jiangsu Province, China. Nonurban residents in Jiangsu will suffer from more excess heat-related cause-specific mortality in 2016-2065 than urban residents. Variations across climate models and RCPs dominated the uncertainty of heat-related mortality estimation whereas population size change only had limited influence. Our findings suggest that targeted climate change mitigation and adaptation measures should be taken in both urban and nonurban areas of Jiangsu Province. Specific public health interventions should be focused on the leading causes of death (stroke, IHD, and COPD), whose health burden will be amplified by a warming climate. Copyright © 2017 Elsevier Ltd. All rights reserved.

Characterizing the impact of projected changes in climate and air quality on human exposures to ozone.

PubMed

Dionisio, Kathie L; Nolte, Christopher G; Spero, Tanya L; Graham, Stephen; Caraway, Nina; Foley, Kristen M; Isaacs, Kristin K

2017-05-01

The impact of climate change on human and environmental health is of critical concern. Population exposures to air pollutants both indoors and outdoors are influenced by a wide range of air quality, meteorological, behavioral, and housing-related factors, many of which are also impacted by climate change. An integrated methodology for modeling changes in human exposures to tropospheric ozone (O 3 ) owing to potential future changes in climate and demographics was implemented by linking existing modeling tools for climate, weather, air quality, population distribution, and human exposure. Human exposure results from the Air Pollutants Exposure Model (APEX) for 12 US cities show differences in daily maximum 8-h (DM8H) exposure patterns and levels by sex, age, and city for all scenarios. When climate is held constant and population demographics are varied, minimal difference in O 3 exposures is predicted even with the most extreme demographic change scenario. In contrast, when population is held constant, we see evidence of substantial changes in O 3 exposure for the most extreme change in climate. Similarly, we see increases in the percentage of the population in each city with at least one O 3 exposure exceedance above 60 p.p.b and 70 p.p.b thresholds for future changes in climate. For these climate and population scenarios, the impact of projected changes in climate and air quality on human exposure to O 3 are much larger than the impacts of changing demographics. These results indicate the potential for future changes in O 3 exposure as a result of changes in climate that could impact human health.

Delivering colonoscopy screening for low-income populations in Suffolk County: strategies, outcomes, and benchmarks.

PubMed

Lane, Dorothy S; Messina, Catherine R; Cavanagh, Mary F; Anderson, Joseph C

2013-08-01

Current and pending legislation provides colorectal cancer screening reimbursement for previously uninsured populations. Colonoscopy is currently the screening method most frequently recommended by physicians for insured patients. The experience of the SCOPE (Suffolk County Preventive Endoscopy) demonstration project (Project SCOPE) at Stony Brook University Medical Center provides a model for delivering colonoscopy screening to low-income populations to meet anticipated increasing demands. Project SCOPE, based in the Department of Preventive Medicine, featured internal collaboration with the academic medical center's large gastroenterology practice and external collaboration with the Suffolk County Department of Health Services' network of community health centers. Colonoscopies were performed by faculty gastroenterologists or supervised fellows. Measures of colonoscopy performance were compared with quality indicators and differences between faculty and supervised fellows were identified. During a 40-month screening period, 800 initial colonoscopies were performed. Approximately 21% of women screened were found to have adenomatous polyps compared with 36% of men. Five cancers were detected. The majority of the population screened (70%) were members of minority populations. African American individuals had a higher percentage of proximally located adenomas (78%) compared with white individuals (65%) and Hispanics (49%), based on the location of the most advanced lesion. Hispanic individuals had a 36% lower risk of adenomas compared with white individuals. Performance measures including the percentage of procedures with adequate bowel preparation, cecum reached, scope withdrawal time, and adenoma detection rate met quality benchmarks when performed by either faculty or supervised fellows. Project SCOPE's operational strategies demonstrated a feasible method for an academic medical center to provide high-quality screening colonoscopy for low-income populations. © 2013 American Cancer Society.

Hierarchical Bayesian Logistic Regression to forecast metabolic control in type 2 DM patients.

PubMed

Dagliati, Arianna; Malovini, Alberto; Decata, Pasquale; Cogni, Giulia; Teliti, Marsida; Sacchi, Lucia; Cerra, Carlo; Chiovato, Luca; Bellazzi, Riccardo

2016-01-01

In this work we present our efforts in building a model able to forecast patients' changes in clinical conditions when repeated measurements are available. In this case the available risk calculators are typically not applicable. We propose a Hierarchical Bayesian Logistic Regression model, which allows taking into account individual and population variability in model parameters estimate. The model is used to predict metabolic control and its variation in type 2 diabetes mellitus. In particular we have analyzed a population of more than 1000 Italian type 2 diabetic patients, collected within the European project Mosaic. The results obtained in terms of Matthews Correlation Coefficient are significantly better than the ones gathered with standard logistic regression model, based on data pooling.

Land, Water and Society in the Maya Lowlands

NASA Astrophysics Data System (ADS)

Murtha, T.; French, K.; Duffy, C.; Webster, D.

2013-12-01

This paper reports the results of our project investigating the long-term spatial and temporal dynamics of land use management, agricultural decision-making and patterns of resource availability in the tropical lowlands of Central America. Overall, our project combines diachronic environmental simulation with historic settlement pattern survey to address a series of long-standing questions about the coupled natural and human (CNH) landscape history in the Central Maya lowlands (at the UNESCO world heritage site of Tikal in the Maya Biosphere Reserve). The paper describes the preliminary results of our project, including changing patterns of land, water, settlement and political history using climate, soil and hydrologic modeling and time series spatial analysis of population and settlement patterns. The critical period of the study, 1000 BC until the present, begins with dispersed settlements accompanied by widespread deforestation and soil erosion. Population size and density grows rapidly for 800 years, while deforestation and erosion rates decline; however, there is striking evidence of political evolution during this period, including the construction of monumental architecture, hieroglyphic monuments detailing wars and alliances, and the construction of a defensive earthwork feature, signaling political territories and possibly delineating natural resource boundaries. Population decline and steady reforestation followed until more recent migration into the region, which has impacted the biosphere ecology. Building on our previous research regionally and comparative research completed in Belize and Mexico, we are modeling sample periods the 3,000-year landscape history of the region, comparing land and water availability to population distributions and what we know about political history. Simulations are generated using historic climate and land use data, primarily relying on the Erosion Productivity Impact Calculator (EPIC) and the Penn State Integrated Hydrologic Modeling System (PIHMgis). This study primarily contributes to understanding long-term environmental change, agrarian decision-making, settlement patterns and critical issues facing agrarian communities globally. Specifically, our research provides an enhanced understanding of one of the most compelling landscape narratives of coupled human and natural history, i.e., the rise and fall of the Maya in the lowland tropical forest of Central America. Importantly, we offer a new approach to studying these broad issues, by integrating coupled climate, soil and hydrologic modeling, with more traditional landscape and anthropological research methods. Data model illustrating relationship between deforestation maize production and population history. 100 year sample periods are highlighted.

Projection specificity in heterogeneous locus coeruleus cell populations: implications for learning and memory

PubMed Central

Uematsu, Akira; Tan, Bao Zhen

2015-01-01

Noradrenergic neurons in the locus coeruleus (LC) play a critical role in many functions including learning and memory. This relatively small population of cells sends widespread projections throughout the brain including to a number of regions such as the amygdala which is involved in emotional associative learning and the medial prefrontal cortex which is important for facilitating flexibility when learning rules change. LC noradrenergic cells participate in both of these functions, but it is not clear how this small population of neurons modulates these partially distinct processes. Here we review anatomical, behavioral, and electrophysiological studies to assess how LC noradrenergic neurons regulate these different aspects of learning and memory. Previous work has demonstrated that subpopulations of LC noradrenergic cells innervate specific brain regions suggesting heterogeneity of function in LC neurons. Furthermore, noradrenaline in mPFC and amygdala has distinct effects on emotional learning and cognitive flexibility. Finally, neural recording data show that LC neurons respond during associative learning and when previously learned task contingencies change. Together, these studies suggest a working model in which distinct and potentially opposing subsets of LC neurons modulate particular learning functions through restricted efferent connectivity with amygdala or mPFC. This type of model may provide a general framework for understanding other neuromodulatory systems, which also exhibit cell type heterogeneity and projection specificity. PMID:26330494

Projection of invertebrate populations in the headwater streams of a temperate catchment under a changing climate.

PubMed

Nukazawa, Kei; Arai, Ryosuke; Kazama, So; Takemon, Yasuhiro

2018-06-14

Climate change places considerable stress on riverine ecosystems by altering flow regimes and increasing water temperature. This study evaluated how water temperature increases under climate change scenarios will affect stream invertebrates in pristine headwater streams. The studied headwater-stream sites were distributed within a temperate catchment of Japan and had similar hydraulic-geographical conditions, but were subject to varying temperature conditions due to altitudinal differences (100 to 850 m). We adopted eight general circulation models (GCMs) to project air temperature under conservative (RCP2.6), intermediate (RCP4.5), and extreme climate scenarios (RCP8.5) during the near (2031-2050) and far (2081-2100) future. Using the water temperature of headwater streams computed by a distributed hydrological-thermal model as a predictor variable, we projected the population density of stream invertebrates in the future scenarios based on generalized linear models. The mean decrease in the temporally averaged population density of Plecoptera was 61.3% among the GCMs, even under RCP2.6 in the near future, whereas density deteriorated even further (90.7%) under RCP8.5 in the far future. Trichoptera density was also projected to greatly deteriorate under RCP8.5 in the far future. We defined taxa that exhibited temperature-sensitive declines under climate change as cold stenotherms and found that most Plecoptera taxa were cold stenotherms in comparison to other orders. Specifically, the taxonomic families that only distribute in Palearctic realm (e.g., Megarcys ochracea and Scopura longa) were selectively assigned, suggesting that Plecoptera family with its restricted distribution in the Palearctic might be a sensitive indicator of climate change. Plecoptera and Trichoptera populations in the headwaters are expected/anticipated to decrease over the considerable geographical range of the catchment, even under the RCP2.6 in the near future. Given headwater invertebrates play important roles in streams, such as contributing to watershed productivity, our results provide useful information for managing streams at the catchment-level. Copyright © 2018 Elsevier B.V. All rights reserved.

Baselines For Land-Use Change In The Tropics: Application ToAvoided Deforestation Projects

DOE Office of Scientific and Technical Information (OSTI.GOV)

Brown, Sandra; Hall, Myrna; Andrasko, Ken

2007-06-01

Although forest conservation activities particularly in thetropics offer significant potential for mitigating carbon emissions,these types of activities have faced obstacles in the policy arena causedby the difficulty in determining key elements of the project cycle,particularly the baseline. A baseline for forest conservation has twomain components: the projected land-use change and the correspondingcarbon stocks in the applicable pools such as vegetation, detritus,products and soil, with land-use change being the most difficult toaddress analytically. In this paper we focus on developing and comparingthree models, ranging from relatively simple extrapolations of pasttrends in land use based on simple drivers such as population growthmore » tomore complex extrapolations of past trends using spatially explicitmodels of land-use change driven by biophysical and socioeconomicfactors. The three models of the latter category used in the analysis atregional scale are The Forest Area Change (FAC) model, the Land Use andCarbon Sequestration (LUCS) model, and the Geographical Modeling (GEOMOD)model. The models were used to project deforestation in six tropicalregions that featured different ecological and socioeconomic conditions,population dynamics, and uses of the land: (1) northern Belize; (2) SantaCruz State, Bolivia; (3) Parana State in Brazil; (4) Campeche, Mexico;(5) Chiapas, Mexico; and (6) Michoacan, Mexico. A comparison of all modeloutputs across all six regions shows that each model produced quitedifferent deforestation baseline. In general, the simplest FAC model,applied at the national administrative-unit scale, projected the highestamount of forest loss (four out of six) and the LUCS model the leastamount of loss (four out of five). Based on simulations of GEOMOD, wefound that readily observable physical and biological factors as well asdistance to areas of past disturbance were each about twice as importantas either sociological/demographic or economic/infrastructure factors(less observable) in explaining empirical land-use patterns. We proposefrom the lessons learned, a methodology comprised of three main steps andsix tasks can be used to begin developing credible baselines. We alsopropose that the baselines be projected over a 10-year period because,although projections beyond 10 years are feasible, they are likely to beunrealistic for policy purposes. In the first step, an historic land-usechange and deforestation estimate is made by determining the analyticdomain (size of the region relative to the size of proposed project),obtaining historic data, analyzing candidate historic baseline drivers,and identifying three to four major drivers. In the second step, abaseline of where deforestation is likely to occur --a potential land-usechange (PLUC) map is produced using a spatial model such as GEOMOD thatuses the key drivers from step one. Then rates of deforestation areprojected over a 10-year baseline period using any of the three models.Using the PLUC maps, projected rates of deforestation, and carbon stockestimates, baselineprojections are developed that can be used for projectGHG accounting and crediting purposes: The final step proposes that, atagreed interval (eg, +10 years), the baseline assumptions about baselinedrivers be re-assessed. This step reviews the viability of the 10-yearbaseline in light of changes in one or more key baseline drivers (e.g.,new roads, new communities, new protected area, etc.). The potentialland-use change map and estimates of rates of deforestation could beredone at the agreed interval, allowing the rates and changes in spatialdrivers to be incorporated into a defense of the existing baseline, orderivation of a new baseline projection.« less

Understanding the Long Run Determinants of Land Use in Global Crop Production

NASA Astrophysics Data System (ADS)

Baldos, U. C.; Hertel, T. W.

2011-12-01

Cropland cover is expected to increase in the future given the projected growth on global demand for crops. Over the past century, crop demand has largely been driven by food demands, which were, in turn driven by a combination of rising population growth and increased per capita incomes, with the former dominating. However, with population growth slowing, and incomes rising more strongly in the developing world - where dietary upgrading is a significant factor - income growth has emerged as a relatively more significant driver of total food demand. At the same time, renewable energy policies across the world have introduced a new, dynamic element to the industrial demand for cropland. However, the drivers of long run cropland use are not limited to those directly related to crop demand. New trends suggest that crop yield growth may be slowing in critical breadbaskets around the world. In addition, some agricultural lands have been lost to urbanization and soil degradation. There is also a growing interest in setting aside land for biodiversity. Finally, there is considerable interest in terrestrial carbon sequestration which could place important new demands on the world's croplands. The co-existence of so many competing factors poses a challenge for properly assessing the long-run global supply and demand for croplands in 2050. In this paper, we quantify the contributions of each of these key drivers to the long-run global cropland use using a partial equilibrium model of global agriculture. To implement the model, we also construct a global database for key land use, agricultural and socio-economic variables from several sources. Our analysis starts with validation of the model over an historical period from 2001 up to 2007-05 (5 years). The model's prediction regarding cropland use is slightly lower than the observed change (+5.8% vs. +8.3%). Decomposition of the drivers of land use change shows that income growth (+3.9%) has a larger impact than population growth (+1.6%), biofuels (+0.2%) and urbanization (-0.3%). Technological change in crop, livestock and processed food production also have a modest impact on global cropland use over this historical period (+0.8%, -0.3% and +0.1%, respectively). We then turn our attention to projections of global land use over the coming decade. Here we project continued expansion in global cropland (13.7%). We then decompose the drivers of this projected change in land use. For example, if population grows at projected rates and yields grow at recent historical rates, then projected cropland use rises by just 1.7%. If we add urbanization, then global cropland use is slightly reduced (+1.5%). Because of the magnitude of the projected production targets, adding biofuels boosts global cropland use strongly (+4.2%) when added to the preceding factors. Adding technological change in the livestock and food processing sectors, as well as growth in per capita incomes boosts projected cropland use to 13.7%. In short, income growth is likely to be the critical driver of global cropland change in the future.

Climate Change and Human Disturbance Can Lead to Local Extinction of Alpine Rock Ptarmigan: New Insight from the Western Italian Alps

PubMed Central

Imperio, Simona; Bionda, Radames; Viterbi, Ramona; Provenzale, Antonello

2013-01-01

Alpine grouses are particularly vulnerable to climate change due to their adaptation to extreme conditions and to their relict distributions in the Alps where global warming has been particularly marked in the last half century. Grouses are also currently threatened by habitat modification and human disturbance, and an assessment of the impact of multiple stressors is needed to predict the fate of Alpine populations of these birds in the next decades. We estimated the effect of climate change and human disturbance on a rock ptarmigan population living in the western Italian Alps by combining an empirical population modelling approach and stochastic simulations of the population dynamics under the a1B climate scenario and two different disturbance scenarios, represented by the development of a ski resort, through 2050.The early appearance of snow-free ground in the previous spring had a favorable effect on the rock ptarmigan population, probably through a higher reproductive success. On the contrary, delayed snowfall in autumn had a negative effect possibly due to a mismatch in time to molt to white winter plumage which increases predation risk. The regional climate model PROTHEUS does not foresee any significant change in snowmelt date in the study area, while the start date of continuous snow cover is expected to be significantly delayed. The net effect in the stochastic projections is a more or less pronounced (depending on the model used) decline in the studied population. The addition of extra-mortality due to collision with ski-lift wires led the population to fatal consequences in most projections. Should these results be confirmed by larger studies the conservation of Alpine populations would deserve more attention. To counterbalance the effects of climate change, the reduction of all causes of death should be pursued, through a strict preservation of the habitats in the present area of occurrence. PMID:24260581

Climate change and human disturbance can lead to local extinction of Alpine rock ptarmigan: new insight from the western Italian Alps.

PubMed

Imperio, Simona; Bionda, Radames; Viterbi, Ramona; Provenzale, Antonello

2013-01-01

Alpine grouses are particularly vulnerable to climate change due to their adaptation to extreme conditions and to their relict distributions in the Alps where global warming has been particularly marked in the last half century. Grouses are also currently threatened by habitat modification and human disturbance, and an assessment of the impact of multiple stressors is needed to predict the fate of Alpine populations of these birds in the next decades. We estimated the effect of climate change and human disturbance on a rock ptarmigan population living in the western Italian Alps by combining an empirical population modelling approach and stochastic simulations of the population dynamics under the a1B climate scenario and two different disturbance scenarios, represented by the development of a ski resort, through 2050.The early appearance of snow-free ground in the previous spring had a favorable effect on the rock ptarmigan population, probably through a higher reproductive success. On the contrary, delayed snowfall in autumn had a negative effect possibly due to a mismatch in time to molt to white winter plumage which increases predation risk. The regional climate model PROTHEUS does not foresee any significant change in snowmelt date in the study area, while the start date of continuous snow cover is expected to be significantly delayed. The net effect in the stochastic projections is a more or less pronounced (depending on the model used) decline in the studied population. The addition of extra-mortality due to collision with ski-lift wires led the population to fatal consequences in most projections. Should these results be confirmed by larger studies the conservation of Alpine populations would deserve more attention. To counterbalance the effects of climate change, the reduction of all causes of death should be pursued, through a strict preservation of the habitats in the present area of occurrence.

STRUCTURED POPULATION MODELS OF HERBIVEROUS ZOOPLANKTON. (R823588)

EPA Science Inventory

The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...

The 4D Nucleome Project

PubMed Central

Dekker, Job; Belmont, Andrew S.; Guttman, Mitchell; Leshyk, Victor O.; Lis, John T.; Lomvardas, Stavros; Mirny, Leonid A.; O’Shea, Clodagh C.; Park, Peter J.; Ren, Bing; Ritland Politz, Joan C.; Shendure, Jay; Zhong, Sheng

2017-01-01

Preface The 4D Nucleome Network aims to develop and apply approaches to map the structure and dynamics of the human and mouse genomes in space and time with the goal of gaining deeper mechanistic understanding of how the nucleus is organized and functions. The project will develop and benchmark experimental and computational approaches for measuring genome conformation and nuclear organization, and investigate how these contribute to gene regulation and other genome functions. Validated experimental approaches will be combined with biophysical modeling to generate quantitative models of spatial genome organization in different biological states, both in cell populations and in single cells. PMID:28905911

The demographic consequences of growing older and bigger in oyster populations.

PubMed

Moore, Jacob L; Lipcius, Romuald N; Puckett, Brandon; Schreiber, Sebastian J

2016-10-01

Structured population models, particularly size- or age-structured, have a long history of informing conservation and natural resource management. While size is often easier to measure than age and is the focus of many management strategies, age-structure can have important effects on population dynamics that are not captured in size-only models. However, relatively few studies have included the simultaneous effects of both age- and size-structure. To better understand how population structure, particularly that of age and size, impacts restoration and management decisions, we developed and compared a size-structured integral projection model (IPM) and an age- and size-structured IPM, using a population of Crassostrea gigas oysters in the northeastern Pacific Ocean. We analyzed sensitivity of model results across values of local retention that give populations decreasing in size to populations increasing in size. We found that age- and size-structured models yielded the best fit to the demographic data and provided more reliable results about long-term demography. Elasticity analysis showed that population growth rate was most sensitive to changes in the survival of both large (>175 mm shell length) and small (<75 mm shell length) oysters, indicating that a maximum size limit, in addition to a minimum size limit, could be an effective strategy for maintaining a sustainable population. In contrast, the purely size-structured model did not detect the importance of large individuals. Finally, patterns in stable age and stable size distributions differed between populations decreasing in size due to limited local retention and populations increasing in size due to high local retention. These patterns can be used to determine population status and restoration success. The methodology described here provides general insight into the necessity of including both age- and size-structure into modeling frameworks when using population models to inform restoration and management decisions. © 2016 by the Ecological Society of America.

A Statistical Modeling Framework for Projecting Future Ambient Ozone and its Health Impact due to Climate Change

PubMed Central

Chang, Howard H.; Hao, Hua; Sarnat, Stefanie Ebelt

2014-01-01

The adverse health effects of ambient ozone are well established. Given the high sensitivity of ambient ozone concentrations to meteorological conditions, the impacts of future climate change on ozone concentrations and its associated health effects are of concern. We describe a statistical modeling framework for projecting future ozone levels and its health impacts under a changing climate. This is motivated by the continual effort to evaluate projection uncertainties to inform public health risk assessment. The proposed approach was applied to the 20-county Atlanta metropolitan area using regional climate model (RCM) simulations from the North American Regional Climate Change Assessment Program. Future ozone levels and ozone-related excesses in asthma emergency department (ED) visits were examined for the period 2041–2070. The computationally efficient approach allowed us to consider 8 sets of climate model outputs based on different combinations of 4 RCMs and 4 general circulation models. Compared to the historical period of 1999–2004, we found consistent projections across climate models of an average 11.5% higher ozone levels (range: 4.8%, 16.2%), and an average 8.3% (range: −7% to 24%) higher number of ozone exceedance days. Assuming no change in the at-risk population, this corresponds to excess ozone-related ED visits ranging from 267 to 466 visits per year. Health impact projection uncertainty was driven predominantly by uncertainty in the health effect association and climate model variability. Calibrating climate simulations with historical observations reduced differences in projections across climate models. PMID:24764746

24 CFR 960.403 - Applicability.

Code of Federal Regulations, 2014 CFR

2014-04-01

... Mixed Population Projects § 960.403 Applicability. (a) This subpart applies to all dwelling units in mixed population projects (as defined in § 960.405), or portions of mixed population projects, assisted...

24 CFR 960.403 - Applicability.

Code of Federal Regulations, 2011 CFR

2011-04-01

... Mixed Population Projects § 960.403 Applicability. (a) This subpart applies to all dwelling units in mixed population projects (as defined in § 960.405), or portions of mixed population projects, assisted...

24 CFR 960.403 - Applicability.

Code of Federal Regulations, 2010 CFR

2010-04-01

... Mixed Population Projects § 960.403 Applicability. (a) This subpart applies to all dwelling units in mixed population projects (as defined in § 960.405), or portions of mixed population projects, assisted...

24 CFR 960.403 - Applicability.

Code of Federal Regulations, 2012 CFR

2012-04-01

... Mixed Population Projects § 960.403 Applicability. (a) This subpart applies to all dwelling units in mixed population projects (as defined in § 960.405), or portions of mixed population projects, assisted...

24 CFR 960.403 - Applicability.

Code of Federal Regulations, 2013 CFR

2013-04-01

... Mixed Population Projects § 960.403 Applicability. (a) This subpart applies to all dwelling units in mixed population projects (as defined in § 960.405), or portions of mixed population projects, assisted...

Topographic, latitudinal and climatic distribution of Pinus coulteri: geographic range limits are not at the edge of the climate envelope

USGS Publications Warehouse

Chardon, Nathalie I.; Cornwell, William K.; Flint, Lorraine E.; Flint, Alan L.; Ackerly, David D.

2015-01-01

With changing climate, many species are projected to move poleward or to higher elevations to track suitable climates. The prediction that species will move poleward assumes that geographically marginal populations are at the edge of the species' climatic range. We studied Pinus coulteri from the center to the northern (poleward) edge of its range, and examined three scenarios regarding the relationship between the geographic and climatic margins of a species' range. We used herbarium and iNaturalist.org records to identify P. coulteri sites, generated a species distribution model based on temperature, precipitation, climatic water deficit, and actual evapotranspiration, and projected suitability under future climate scenarios. In fourteen populations from the central to northern portions of the range, we conducted field studies and recorded elevation, slope and aspect (to estimate solar insolation) to examine relationships between local and regional distributions. We found that northern populations of P. coulteri do not occupy the cold or wet edge of the species' climatic range; mid-latitude, high elevation populations occupy the cold margin. Aspect and insolation of P. coulteri populations changed significantly across latitudes and elevations. Unexpectedly, northern, low-elevation stands occupy north-facing aspects and receive low insolation, while central, high-elevation stands grow on more south-facing aspects that receive higher insolation. Modeled future climate suitability is projected to be highest in the central, high elevation portion of the species range, and in low-lying coastal regions under some scenarios, with declining suitability in northern areas under most future scenarios. For P. coulteri, the lack of high elevation habitat combined with a major dispersal barrier may limit northward movement in response to a warming climate. Our analyses demonstrate the importance of distinguishing geographically vs. climatically marginal populations, and the importance of quantitative analysis of the realized climate space to understand species range limits.

Agent-Based Phytoplankton Models of Cellular and Population Processes: Fostering Individual-Based Learning in Undergraduate Research

NASA Astrophysics Data System (ADS)

Berges, J. A.; Raphael, T.; Rafa Todd, C. S.; Bate, T. C.; Hellweger, F. L.

2016-02-01

Engaging undergraduate students in research projects that require expertise in multiple disciplines (e.g. cell biology, population ecology, and mathematical modeling) can be challenging because they have often not developed the expertise that allows them to participate at a satisfying level. Use of agent-based modeling can allow exploration of concepts at more intuitive levels, and encourage experimentation that emphasizes processes over computational skills. Over the past several years, we have involved undergraduate students in projects examining both ecological and cell biological aspects of aquatic microbial biology, using the freely-downloadable, agent-based modeling environment NetLogo (https://ccl.northwestern.edu/netlogo/). In Netlogo, actions of large numbers of individuals can be simulated, leading to complex systems with emergent behavior. The interface features appealing graphics, monitors, and control structures. In one example, a group of sophomores in a BioMathematics program developed an agent-based model of phytoplankton population dynamics in a pond ecosystem, motivated by observed macroscopic changes in cell numbers (due to growth and death), and driven by responses to irradiance, temperature and a limiting nutrient. In a second example, junior and senior undergraduates conducting Independent Studies created a model of the intracellular processes governing stress and cell death for individual phytoplankton cells (based on parameters derived from experiments using single-cell culturing and flow cytometry), and then this model was embedded in the agents in the pond ecosystem model. In our experience, students with a range of mathematical abilities learned to code quickly and could use the software with varying degrees of sophistication, for example, creation of spatially-explicit two and three-dimensional models. Skills developed quickly and transferred readily to other platforms (e.g. Matlab).

Changes in Urban Climate due to Future Land-Use Changes based on Population Changes in the Nagoya Region

NASA Astrophysics Data System (ADS)

Adachi, S. A.; Hara, M.; Takahashi, H. G.; Ma, X.; Yoshikane, T.; Kimura, F.

2013-12-01

Severe hot weather in summer season becomes a big social problem in metropolitan areas, including the Nagoya region in Japan. Surface air temperature warming is projected in the future. Therefore, the reduction of surface air temperature is an urgent issue in the urban area. Although there are several studies dealing with the effects of global climate change and urbanization to the local climate in the future, these studies tend to ignore the future population changes. This study estimates future land-use scenarios associated with the multi-projections of future population and investigates the impacts of these scenarios on the surface temperature change. The Weather Research and Forecast model ver. 3.3.1 (hereafter, WRF) was used in this study. The horizontal resolutions were 20km, 4km, and 2km, for outer, middle, and inner domains, respectively. The results from the inner domain, covering the Nagoya region, were used for the analysis. The Noah land surface model and the single-layer urban canopy model were applied to calculate the land surface processes and urban surface processes, respectively. The initial and boundary conditions were given from the NCEP/NCAR reanalysis data in August 2010. The urban area ratio used in the WRF model was calculated from the future land-use data provided by the S8 project. The land-use data was created as follows. (1) Three scenarios of population, namely, with high-fertility assumption and low-mortality assumption (POP-high), with medium-fertility assumption and medium-mortality assumption (POP-med), and with low-fertility assumption and high-mortality assumption (POP-low), are estimated using the method proposed by Ariga and Matsuhashi (2012). These scenarios are based on the future projections provided by the National Institute of Population and Social Security Research. (2) The future changes in urban area ratio were assumed to be proportional to the population change (Hanasaki et al., 2012). The averaged urban area ratio in the Nagoya region was 0.37 in 2010. The area ratios were projected to reach a peak in 2010 to 2020, and then to decrease in the future in all of scenarios. The urban heat island intensity in the Nagoya region is about 1.5°C in 2010. In contrast, the differences of surface temperature is -0.17°C, -0.21°C, and -0.30°C in POP-high, POP-med, and POP-low, from the current situation in 2010. These impacts correspond to the 10% to 20% of current urban heat island intensity. However, the changes in the efficiency of energy consumption were not considered. Considering that the future surface temperature change is projected to be about 1.2°C to 4°C in 2070, it is required to quantitatively evaluate future urban scenarios including the mitigation strategies for urban heat island such as the improvement of energy consumption, greening, and so on. Acknowledgments. This study was supported by the Research Program on Climate Change Adaptation (RECCA) Fund by Ministry of Education, Culture, Sports, Science and Technology (MEXT) of Japan and the Global Environment Research Fund (S-8) of the Ministry of the Environment of Japan.

Sustainability: the elusive dimension of international health projects.

PubMed

Edwards, Nancy C; Roelofs, Susan M

2006-01-01

The Canada-China Yunnan Maternal and Child Health Project (1997-2003) sought to improve the quality of village life and promote development of productivity and social prosperity in Yunnan province, China. The project targeted grassroots maternal and child health workers: new and in-service village doctors; traditional village midwives; doctors at township health centres; doctors at county maternal and child health hospitals; and provincial health staff. Ten impoverished counties (population 2.2 million) in Yunnan province with high proportions of ethnic minority populations. There were three major innovations: training grassroots maternal and child health workers in participatory and community-based approaches and clinical skills; designing a model comprehensive referral system including provision of basic equipment; and introducing participatory monitoring and evaluation methods. Strategies to support sustainability were built into the project from the outset. Over 4,000 village, township, and county health workers received training. Maternal, infant, and under-five mortality rates declined over 30% in project counties. Project innovations were disseminated throughout the province, into other donor-funded initiatives, and integrated into national health projects by local partners. Maintaining the long-term benefits of international health interventions depends on sustaining innovations beyond short project timelines. Achieving sustainability poses a conundrum to implementing agencies. Three mechanisms influenced uptake in the Yunnan project: maintaining a good fit between core project elements and the existing health system; developing adequate organizational supports; and creating a handover plan from the outset. This project highlights some of the ways in which sustainability can be operationalized.

Estimation of Potential Population Level Effects of Contaminants on Wildlife

DOE Office of Scientific and Technical Information (OSTI.GOV)

Loar, J.M.

2001-06-11

The objective of this project is to provide DOE with improved methods to assess risks from contaminants to wildlife populations. The current approach for wildlife risk assessment consists of comparison of contaminant exposure estimates for individual animals to literature-derived toxicity test endpoints. These test endpoints are assumed to estimate thresholds for population-level effects. Moreover, species sensitivities to contaminants is one of several criteria to be considered when selecting assessment endpoints (EPA 1997 and 1998), yet data on the sensitivities of many birds and mammals are lacking. The uncertainties associated with this approach are considerable. First, because toxicity data are notmore » available for most potential wildlife endpoint species, extrapolation of toxicity data from test species to the species of interest is required. There is no consensus on the most appropriate extrapolation method. Second, toxicity data are represented as statistical measures (e.g., NOAEL s or LOAELs) that provide no information on the nature or magnitude of effects. The level of effect is an artifact of the replication and dosing regime employed, and does not indicate how effects might increase with increasing exposure. Consequently, slight exceedance of a LOAEL is not distinguished from greatly exceeding it. Third, the relationship of toxic effects on individuals to effects on populations is poorly estimated by existing methods. It is assumed that if the exposure of individuals exceeds levels associated with impaired reproduction, then population level effects are likely. Uncertainty associated with this assumption is large because depending on the reproductive strategy of a given species, comparable levels of reproductive impairment may result in dramatically different population-level responses. This project included several tasks to address these problems: (1) investigation of the validity of the current allometric scaling approach for interspecies extrapolation an d development of new scaling models; (2) development of dose-response models for toxicity data presented in the literature; and (3) development of matrix-based population models that were coupled with dose-response models to provide realistic estimation of population-level effects for individual responses.« less

A population genetic model for high-elevation five-needle pines: Projecting population outcomes in the presence of white pine blister rust

Treesearch

A. W. Schoettle; J. G. Klutsch; M. F. Antolin; S. Field

2011-01-01

The slow growth and long generation time of the five-needle pines have historically enabled these trees to persist on the landscape for centuries, but without sufficient regeneration opportunities these same traits hinder the species' ability to adapt to novel stresses such as the non-native disease white pine blister rust (WPBR). Increasing the frequency of...

The impacts of climate, land use, and demography on fires during the 21st century simulated by CLM-CN

NASA Astrophysics Data System (ADS)

Kloster, S.; Mahowald, N. M.; Randerson, J. T.; Lawrence, P. J.

2012-01-01

Landscape fires during the 21st century are expected to change in response to multiple agents of global change. Important controlling factors include climate controls on the length and intensity of the fire season, fuel availability, and fire management, which are already anthropogenically perturbed today and are predicted to change further in the future. An improved understanding of future fires will contribute to an improved ability to project future anthropogenic climate change, as changes in fire activity will in turn impact climate. In the present study we used a coupled-carbon-fire model to investigate how changes in climate, demography, and land use may alter fire emissions. We used climate projections following the SRES A1B scenario from two different climate models (ECHAM5/MPI-OM and CCSM) and changes in population. Land use and harvest rates were prescribed according to the RCP 45 scenario. In response to the combined effect of all these drivers, our model estimated, depending on our choice of climate projection, an increase in future (2075-2099) fire carbon emissions by 17 and 62% compared to present day (1985-2009). The largest increase in fire emissions was predicted for Southern Hemisphere South America for both climate projections. For Northern Hemisphere Africa, a region that contributed significantly to the global total fire carbon emissions, the response varied between a decrease and an increase depending on the climate projection. We disentangled the contribution of the single forcing factors to the overall response by conducting an additional set of simulations in which each factor was individually held constant at pre-industrial levels. The two different projections of future climate change evaluated in this study led to increases in global fire carbon emissions by 22% (CCSM) and 66% (ECHAM5/MPI-OM). The RCP 45 projection of harvest and land use led to a decrease in fire carbon emissions by -5%. The RCP 26 and RCP 60 harvest and landuse projections caused decreases around -20%. Changes in human ignition led to an increase of 20%. When we also included changes in fire management efforts to suppress fires in densely populated areas, global fire carbon emission decreased by -6% in response to changes in population density. We concluded from this study that changes in fire emissions in the future are controlled by multiple interacting factors. Although changes in climate led to an increase in future fire emissions this could be globally counterbalanced by coupled changes in land use, harvest, and demography.

Fire management, managed relocation, and land conservation options for long-lived obligate seeding plants under global changes in climate, urbanization, and fire regime.

PubMed

Bonebrake, Timothy C; Syphard, Alexandra D; Franklin, Janet; Anderson, Kurt E; Akçakaya, H Resit; Mizerek, Toni; Winchell, Clark; Regan, Helen M

2014-08-01

Most species face multiple anthropogenic disruptions. Few studies have quantified the cumulative influence of multiple threats on species of conservation concern, and far fewer have quantified the potential relative value of multiple conservation interventions in light of these threats. We linked spatial distribution and population viability models to explore conservation interventions under projected climate change, urbanization, and changes in fire regime on a long-lived obligate seeding plant species sensitive to high fire frequencies, a dominant plant functional type in many fire-prone ecosystems, including the biodiversity hotspots of Mediterranean-type ecosystems. First, we investigated the relative risk of population decline for plant populations in landscapes with and without land protection under an existing habitat conservation plan. Second, we modeled the effectiveness of relocating both seedlings and seeds from a large patch with predicted declines in habitat area to 2 unoccupied recipient patches with increasing habitat area under 2 projected climate change scenarios. Finally, we modeled 8 fire return intervals (FRIs) approximating the outcomes of different management strategies that effectively control fire frequency. Invariably, long-lived obligate seeding populations remained viable only when FRIs were maintained at or above a minimum level. Land conservation and seedling relocation efforts lessened the impact of climate change and land-use change on obligate seeding populations to differing degrees depending on the climate change scenario, but neither of these efforts was as generally effective as frequent translocation of seeds. While none of the modeled strategies fully compensated for the effects of land-use and climate change, an integrative approach managing multiple threats may diminish population declines for species in complex landscapes. Conservation plans designed to mitigate the impacts of a single threat are likely to fail if additional threats are ignored. © 2014 Society for Conservation Biology.

Financial arrangement selection for energy management projects

NASA Astrophysics Data System (ADS)

Woodroof, Eric Aubrey

Scope and method of study. The purpose of this study was to develop a model (E-FUND) to help facility managers select financial arrangements for energy management projects (EMPs). The model was developed with the help of a panel of expert financiers. The panel also helped develop a list of key objectives critical to the decision process. The E-FUND model was tested by a population of facility managers in four case studies. Findings and conclusions. The results may indicate that having a high economic benefit (from an EMP) is not overwhelmingly important, when compared to other qualitative objectives. The results may also indicate that the true lease and performance contract may be the most applicable financial arrangements for EMPs.

Anticipating Forest and Range Land Development in Central Oregon (USA) for Landscape Analysis, with an Example Application Involving Mule Deer

NASA Astrophysics Data System (ADS)

Kline, Jeffrey D.; Moses, Alissa; Burcsu, Theresa

2010-05-01

Forest policymakers, public lands managers, and scientists in the Pacific Northwest (USA) seek ways to evaluate the landscape-level effects of policies and management through the multidisciplinary development and application of spatially explicit methods and models. The Interagency Mapping and Analysis Project (IMAP) is an ongoing effort to generate landscape-wide vegetation data and models to evaluate the integrated effects of disturbances and management activities on natural resource conditions in Oregon and Washington (USA). In this initial analysis, we characterized the spatial distribution of forest and range land development in a four-county pilot study region in central Oregon. The empirical model describes the spatial distribution of buildings and new building construction as a function of population growth, existing development, topography, land-use zoning, and other factors. We used the model to create geographic information system maps of likely future development based on human population projections to inform complementary landscape analyses underway involving vegetation, habitat, and wildfire interactions. In an example application, we use the model and resulting maps to show the potential impacts of future forest and range land development on mule deer ( Odocoileus hemionus) winter range. Results indicate significant development encroachment and habitat loss already in 2000 with development located along key migration routes and increasing through the projection period to 2040. The example application illustrates a simple way for policymakers and public lands managers to combine existing data and preliminary model outputs to begin to consider the potential effects of development on future landscape conditions.

Probabilistic models of genetic variation in structured populations applied to global human studies.

PubMed

Hao, Wei; Song, Minsun; Storey, John D

2016-03-01

Modern population genetics studies typically involve genome-wide genotyping of individuals from a diverse network of ancestries. An important problem is how to formulate and estimate probabilistic models of observed genotypes that account for complex population structure. The most prominent work on this problem has focused on estimating a model of admixture proportions of ancestral populations for each individual. Here, we instead focus on modeling variation of the genotypes without requiring a higher-level admixture interpretation. We formulate two general probabilistic models, and we propose computationally efficient algorithms to estimate them. First, we show how principal component analysis can be utilized to estimate a general model that includes the well-known Pritchard-Stephens-Donnelly admixture model as a special case. Noting some drawbacks of this approach, we introduce a new 'logistic factor analysis' framework that seeks to directly model the logit transformation of probabilities underlying observed genotypes in terms of latent variables that capture population structure. We demonstrate these advances on data from the Human Genome Diversity Panel and 1000 Genomes Project, where we are able to identify SNPs that are highly differentiated with respect to structure while making minimal modeling assumptions. A Bioconductor R package called lfa is available at http://www.bioconductor.org/packages/release/bioc/html/lfa.html jstorey@princeton.edu Supplementary data are available at Bioinformatics online. © The Author 2015. Published by Oxford University Press.

Taking a 'Big Data' approach to data quality in a citizen science project.

PubMed

Kelling, Steve; Fink, Daniel; La Sorte, Frank A; Johnston, Alison; Bruns, Nicholas E; Hochachka, Wesley M

2015-11-01

Data from well-designed experiments provide the strongest evidence of causation in biodiversity studies. However, for many species the collection of these data is not scalable to the spatial and temporal extents required to understand patterns at the population level. Only data collected from citizen science projects can gather sufficient quantities of data, but data collected from volunteers are inherently noisy and heterogeneous. Here we describe a 'Big Data' approach to improve the data quality in eBird, a global citizen science project that gathers bird observations. First, eBird's data submission design ensures that all data meet high standards of completeness and accuracy. Second, we take a 'sensor calibration' approach to measure individual variation in eBird participant's ability to detect and identify birds. Third, we use species distribution models to fill in data gaps. Finally, we provide examples of novel analyses exploring population-level patterns in bird distributions.

Evolution in Stage-Structured Populations

PubMed Central

Barfield, Michael; Holt, Robert D.; Gomulkiewicz, Richard

2016-01-01

For many organisms, stage is a better predictor of demographic rates than age. Yet no general theoretical framework exists for understanding or predicting evolution in stage-structured populations. Here, we provide a general modeling approach that can be used to predict evolution and demography of stage-structured populations. This advances our ability to understand evolution in stage-structured populations to a level previously available only for populations structured by age. We use this framework to provide the first rigorous proof that Lande’s theorem, which relates adaptive evolution to population growth, applies to stage-classified populations, assuming only normality and that evolution is slow relative to population dynamics. We extend this theorem to allow for different means or variances among stages. Our next major result is the formulation of Price’s theorem, a fundamental law of evolution, for stage-structured populations. In addition, we use data from Trillium grandiflorum to demonstrate how our models can be applied to a real-world population and thereby show their practical potential to generate accurate projections of evolutionary and population dynamics. Finally, we use our framework to compare rates of evolution in age- versus stage-structured populations, which shows how our methods can yield biological insights about evolution in stage-structured populations. PMID:21460563

Modeling tradeoffs in avian life history traits and consequences for population growth

USGS Publications Warehouse

Clark, M.E.; Martin, T.E.

2007-01-01

Variation in population dynamics is inherently related to life history characteristics of species, which vary markedly even within phylogenetic groups such as passerine birds. We computed the finite rate of population change (??) from a matrix projection model and from mark-recapture observations for 23 bird species breeding in northern Arizona. We used sensitivity analyses and a simulation model to separate contributions of different life history traits to population growth rate. In particular we focused on contrasting effects of components of reproduction (nest success, clutch size, number of clutches, and juvenile survival) versus adult survival on ??. We explored how changes in nest success or adult survival coupled to costs in other life history parameters affected ?? over a life history gradient provided by our 23 Arizona species, as well as a broader sample of 121 North American passerine species. We further examined these effects for more than 200 passeriform and piciform populations breeding across North America. Model simulations indicate nest success and juvenile survival exert the largest effects on population growth in species with moderate to high reproductive output, whereas adult survival contributed more to population growth in long-lived species. Our simulations suggest that monitoring breeding success in populations across a broad geographic area provides an important index for identifying neotropical migratory populations at risk of serious population declines and a potential method for identifying large-scale mechanisms regulating population dynamics. ?? 2007 Elsevier B.V. All rights reserved.

Nonevent stress contributes to mental health disparities based on sexual orientation: evidence from a personal projects analysis.

PubMed

Frost, David M; LeBlanc, Allen J

2014-09-01

This study examined the role of nonevent stress--in the form of frustrated personal project pursuits in the arenas of relationships and work--as a contributing factor to mental health disparities between heterosexual and lesbian, gay, and bisexual (LGB) populations. A purposive sample of 431 LGB (55%) and heterosexually identified (45%) individuals living in the United States and Canada completed the Personal Project Inventory by describing and rating core personal projects they were pursuing. The intensity of perceived barriers to the achievement of relationship- and work-related personal projects served as indicators nonevent stress. Hierarchical linear regression models tested the hypothesis that nonevent stress contributes to the association between sexual orientation and two indicators of mental health: depressive symptoms and psychological well-being. LGB individuals had significantly more depressive symptoms and lower levels of psychological well-being than heterosexuals. Indicators of nonevent stress were significantly associated with mental health outcomes and their inclusion in models attenuated sexual orientation differences in mental health. The critical indirect pathway leading from sexual minority status to mental health occurred via barriers to relationship projects from interpersonal sources. This research suggests that nonevent stress because of structural and interpersonal stigma may contribute to mental health disparities between LGB and heterosexual individuals. The findings have important implications for policy reform around same-sex relationship recognition and workplace discrimination. Future research and clinical work will benefit by expanding existing foci on stress to include nonevent stressors to better understand and address mental health problems, particularly in LGB populations.

Nonevent Stress Contributes to Mental Health Disparities Based on Sexual Orientation: Evidence From a Personal Projects Analysis

PubMed Central

Frost, David M.; LeBlanc, Allen J.

2015-01-01

This study examined the role of nonevent stress—in the form of frustrated personal project pursuits in the arenas of relationships and work—as a contributing factor to mental health disparities between heterosexual and lesbian, gay, and bisexual (LGB) populations. A purposive sample of 431 LGB (55%) and heterosexually identified (45%) individuals living in the United States and Canada completed the Personal Project Inventory by describing and rating core personal projects they were pursuing. The intensity of perceived barriers to the achievement of relationship- and work-related personal projects served as indicators nonevent stress. Hierarchical linear regression models tested the hypothesis that nonevent stress contributes to the association between sexual orientation and two indicators of mental health: depressive symptoms and psychological well-being. LGB individuals had significantly more depressive symptoms and lower levels of psychological well-being than heterosexuals. Indicators of nonevent stress were significantly associated with mental health outcomes and their inclusion in models attenuated sexual orientation differences in mental health. The critical indirect pathway leading from sexual minority status to mental health occurred via barriers to relationship projects from interpersonal sources. This research suggests that nonevent stress because of structural and interpersonal stigma may contribute to mental health disparities between LGB and heterosexual individuals. The findings have important implications for policy reform around same-sex relationship recognition and workplace discrimination. Future research and clinical work will benefit by expanding existing foci on stress to include nonevent stressors to better understand and address mental health problems, particularly in LGB populations. PMID:25265219

Aging Will Amplify the Heat-related Mortality Risk under a Changing Climate: Projection for the Elderly in Beijing, China

NASA Astrophysics Data System (ADS)

Li, Tiantian; Horton, Radley M.; Bader, Daniel A.; Zhou, Maigeng; Liang, Xudong; Ban, Jie; Sun, Qinghua; Kinney, Patrick L.

2016-06-01

An aging population could substantially enhance the burden of heat-related health risks in a warming climate because of their higher susceptibility to extreme heat health effects. Here, we project heat-related mortality for adults 65 years and older in Beijing China across 31 downscaled climate models and 2 representative concentration pathways (RCPs) in the 2020s, 2050s, and 2080s. Under a scenario of medium population and RCP8.5, by the 2080s, Beijing is projected to experience 14,401 heat-related deaths per year for elderly individuals, which is a 264.9% increase compared with the 1980s. These impacts could be moderated through adaptation. In the 2080s, even with the 30% and 50% adaptation rate assumed in our study, the increase in heat-related death is approximately 7.4 times and 1.3 times larger than in the 1980s respectively under a scenario of high population and RCP8.5. These findings could assist countries in establishing public health intervention policies for the dual problems of climate change and aging population. Examples could include ensuring facilities with large elderly populations are protected from extreme heat (for example through back-up power supplies and/or passive cooling) and using databases and community networks to ensure the home-bound elderly are safe during extreme heat events.

Aging Will Amplify the Heat-Related Mortality Risk Under a Changing Climate: Projection for the Elderly in Beijing, China

NASA Technical Reports Server (NTRS)

Li, Tiantian; Horton, Radley M.; Bader, Daniel A.; Zhou, Maigeng; Liang, Xudong; Ban, Jie; Sun, Qinghua; Kinney, Patrick L.

2016-01-01

An aging population could substantially enhance the burden of heat-related health risks in a warming climate because of their higher susceptibility to extreme heat health effects. Here, we project heatrelated mortality for adults 65 years and older in Beijing China across 31 downscaled climate models and 2 representative concentration pathways (RCPs) in the 2020s, 2050s, and 2080s. Under a scenario of medium population and RCP8.5, by the 2080s, Beijing is projected to experience 14,401 heat-related deaths per year for elderly individuals, which is a 264.9% increase compared with the 1980s. These impacts could be moderated through adaptation. In the 2080s, even with the 30% and 50% adaptation rate assumed in our study, the increase in heat-related death is approximately 7.4 times and 1.3 times larger than in the 1980s respectively under a scenario of high population and RCP8.5. These findings could assist countries in establishing public health intervention policies for the dual problems of climate change and aging population. Examples could include ensuring facilities with large elderly populations are protected from extreme heat (for example through back-up power supplies and/or passive cooling) and using databases and community networks to ensure the home-bound elderly are safe during extreme heat events.

Interim 2001-based national population projections for the United Kingdom and constituent countries.

PubMed

Shaw, Chris

2003-01-01

This article describes new 2001-based national population projections which were carried out following the publication in September 2002 of the first results of the 2001 Census. These "interim" projections, carried out by the Government Actuary in consultation with the Registrars General, take preliminary account of the results of the Census which showed that the base population used in previous projections was overestimated. The interim projections also incorporate a reduced assumption of net international migration to the United Kingdom, informed by the first results of the 2001 Census and taking account of more recent migration information. The population of the United Kingdom is now projected to increase from an estimated 58.8 million in 2001 to reach 63.2 million by 2026. The projected population at 2026 is about 1.8 million (2.8 per cent) lower than in the previous (2000-based) projections.

Effects of uncertainty and variability on population declines and IUCN Red List classifications.

PubMed

Rueda-Cediel, Pamela; Anderson, Kurt E; Regan, Tracey J; Regan, Helen M

2018-01-22

The International Union for Conservation of Nature (IUCN) Red List Categories and Criteria is a quantitative framework for classifying species according to extinction risk. Population models may be used to estimate extinction risk or population declines. Uncertainty and variability arise in threat classifications through measurement and process error in empirical data and uncertainty in the models used to estimate extinction risk and population declines. Furthermore, species traits are known to affect extinction risk. We investigated the effects of measurement and process error, model type, population growth rate, and age at first reproduction on the reliability of risk classifications based on projected population declines on IUCN Red List classifications. We used an age-structured population model to simulate true population trajectories with different growth rates, reproductive ages and levels of variation, and subjected them to measurement error. We evaluated the ability of scalar and matrix models parameterized with these simulated time series to accurately capture the IUCN Red List classification generated with true population declines. Under all levels of measurement error tested and low process error, classifications were reasonably accurate; scalar and matrix models yielded roughly the same rate of misclassifications, but the distribution of errors differed; matrix models led to greater overestimation of extinction risk than underestimations; process error tended to contribute to misclassifications to a greater extent than measurement error; and more misclassifications occurred for fast, rather than slow, life histories. These results indicate that classifications of highly threatened taxa (i.e., taxa with low growth rates) under criterion A are more likely to be reliable than for less threatened taxa when assessed with population models. Greater scrutiny needs to be placed on data used to parameterize population models for species with high growth rates, particularly when available evidence indicates a potential transition to higher risk categories. © 2018 Society for Conservation Biology.

Comparative Longterm Mortality Trends in Cancer vs. Ischemic Heart Disease in Puerto Rico.

PubMed

Torres, David; Pericchi, Luis R; Mattei, Hernando; Zevallos, Juan C

2017-06-01

Although contemporary mortality data are important for health assessment and planning purposes, their availability lag several years. Statistical projection techniques can be employed to obtain current estimates. This study aimed to assess annual trends of mortality in Puerto Rico due to cancer and Ischemic Heart Disease (IHD), and to predict shorterm and longterm cancer and IHD mortality figures. Age-adjusted mortality per 100,000 population projections with a 50% interval probability were calculated utilizing a Bayesian statistical approach of Age-Period-Cohort dynamic model. Multiple cause-of-death annual files for years 1994-2010 for Puerto Rico were used to calculate shortterm (2011-2012) predictions. Longterm (2013-2022) predictions were based on quinquennial data. We also calculated gender differences in rates (men-women) for each study period. Mortality rates for women were similar for cancer and IHD in the 1994-1998 period, but changed substantially in the projected 2018-2022 period. Cancer mortality rates declined gradually overtime, and the gender difference remained constant throughout the historical and projected trends. A consistent declining trend for IHD historical annual mortality rate was observed for both genders, with a substantial changepoint around 2004-2005 for men. The initial gender difference of 33% (80/100,00 vs. 60/100,000) in mortality rates observed between cancer and IHD in the 1994-1998 period increased to 300% (60/100,000 vs. 20/100,000) for the 2018-2022 period. The APC projection model accurately projects shortterm and longterm mortality trends for cancer and IHD in this population: The steady historical and projected cancer mortality rates contrasts with the substantial decline in IHD mortality rates, especially in men.

Projection of ambient PM2.5 exposure in India and associated health burden

NASA Astrophysics Data System (ADS)

Chowdhury, Sourangsu; Dey, Sagnik; Smith, Kirk

2017-04-01

Ambient particulate matter with diameter < 2.5 µm (PM2.5) is the major criteria pollutant for health assessments of air quality. (WHO, 2006). Exposure to PM2.5 has potential health risks due to cardiovascular and respiratory diseases leading to premature mortality. The annual premature mortality burden from ambient PM2.5 exposure in India is large ( 0.6-0.8 million). It is important to understand how the ambient PM2.5 concentration will change in future under the warming climate and how it translates into premature mortality, when the population distribution exposed to the pollution and baseline mortality are expected to change in response to changes in socio-economic condition to adapt to climate change impacts. We estimate ambient PM2.5 future (up to 2100) by adopting 2 approaches. In the first approach, PM2.5 is estimated as a product of AOD from the CMIP5 models (under both RCP4.5 and RCP8.5 scenarios) and the present day conversion factor estimated by the Geos-CHEM model as a function of present day meteorological conditions and emission. The second approach involves adding up all the PM2.5 components (SO4, NH4, BC, SOA, POA, a fraction of sea salt and dust) available from 13 CMIP5 models under the RCP4.5 and RCP8.5 climate change scenarios. The change is represented in relative terms with respect to the baseline period PM2.5 exposure (2001-2005), when satellite data are available and the CMIP5 models are run in historical mode. The difference between these two approaches implies the role of meteorology in modulating PM2.5 exposure for future due to climate change. We present the decadal statistics and separate the role of meteorology from the combined role of meteorology and emission in modulating PM2.5 variability. We project premature mortality for future using population for future, projected under 5 SSP (Shared Socioeconomic Pathways) scenarios (definitions of these scenarios are provided in Table 1) developed by IIASA. The population under these five scenarios have varying capability to adapt and mitigate to cope up with the changing climate. We estimate premature mortality for two cases, (i) assuming BM to remain constant as of the present day, and (ii) modifying the BM as a function of gross development product. Relative risk is estimated using the IER function. Hence we develop customized scenarios for estimating premature death by linking projected PM2.5 under 2 RCP scenarios with population and baseline mortality from 5 SSP scenarios for each decade up to 2100, creating a total of 10 combined scenarios for each decade. We project that if baseline mortality remains as of present day (WHO 2011) then premature mortality increases up to the middle of the century and then decreases, but never decreases below the present day premature mortality, whereas if we assume that baseline mortality varies as a exponentially decaying function of GDP, premature mortality for future decades are projected to decrease below the present day estimate of premature mortality as GDP is projected to increase in all the 5 SSP scenarios. We further separate the effect of future meteorology, epidemiological changes and demographic changes in future on projected premature mortality. This study can help in the government in developing policies for future in order to avert the projected mortality and follow all the requirements that the best case scenario deserves in order to mitigate the effect of PM2.5 on mortality.

Meeting the Sustainable Development Goals leads to lower world population growth

PubMed Central

Abel, Guy J.; Barakat, Bilal; KC, Samir; Lutz, Wolfgang

2016-01-01

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. PMID:27911797

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

PubMed

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.

Future of family support: Projected living arrangements and income sources of older people in Hong Kong up to 2030.

PubMed

Ng, Kok-Hoe

2016-06-01

The study aims to project future trends in living arrangements and access to children's cash contributions and market income sources among older people in Hong Kong. A cell-based model was constructed by combining available population projections, labour force projections, an extrapolation of the historical trend in living arrangements based on national survey datasets and a regression model on income sources. Under certain assumptions, the proportion of older people living with their children may decline from 59 to 48% during 2006-2030. Although access to market income sources may improve slightly, up to 20% of older people may have no access to either children's financial support or market income sources, and will not live with their children by 2030. Family support is expected to contract in the next two decades. Public pensions should be expanded to protect financially vulnerable older people. © 2015 AJA Inc.

The effect of Missouri mathematics project learning model on students’ mathematical problem solving ability

NASA Astrophysics Data System (ADS)

Handayani, I.; Januar, R. L.; Purwanto, S. E.

2018-01-01

This research aims to know the influence of Missouri Mathematics Project Learning Model to Mathematical Problem-solving Ability of Students at Junior High School. This research is a quantitative research and uses experimental research method of Quasi Experimental Design. The research population includes all student of grade VII of Junior High School who are enrolled in the even semester of the academic year 2016/2017. The Sample studied are 76 students from experimental and control groups. The sampling technique being used is cluster sampling method. The instrument is consisted of 7 essay questions whose validity, reliability, difficulty level and discriminating power have been tested. Before analyzing the data by using t-test, the data has fulfilled the requirement for normality and homogeneity. The result of data shows that there is the influence of Missouri mathematics project learning model to mathematical problem-solving ability of students at junior high school with medium effect.

A long-term study of ecological impacts of river channelization on the population of an endangered fish: Lessons learned for assessment and restoration

USGS Publications Warehouse

Roberts, James H.; Anderson, Gregory B.; Angermeier, Paul

2016-01-01

Projects to assess environmental impact or restoration success in rivers focus on project-specific questions but can also provide valuable insights for future projects. Both restoration actions and impact assessments can become “adaptive” by using the knowledge gained from long-term monitoring and analysis to revise the actions, monitoring, conceptual model, or interpretation of findings so that subsequent actions or assessments are better informed. Assessments of impact or restoration success are especially challenging when the indicators of interest are imperiled species and/or the impacts being addressed are complex. From 1997 to 2015, we worked closely with two federal agencies to monitor habitat availability for and population density of Roanoke logperch (Percina rex), an endangered fish, in a 24-km-long segment of the upper Roanoke River, VA. We primarily used a Before-After-Control-Impact analytical framework to assess potential impacts of a river channelization project on the P. rex population. In this paper, we summarize how our extensive monitoring facilitated the evolution of our (a) conceptual understanding of the ecosystem and fish population dynamics; (b) choices of ecological indicators and analytical tools; and (c) conclusions regarding the magnitude, mechanisms, and significance of observed impacts. Our experience with this case study taught us important lessons about how to adaptively develop and conduct a monitoring program, which we believe are broadly applicable to assessments of environmental impact and restoration success in other rivers. In particular, we learned that (a) pre-treatment planning can enhance monitoring effectiveness, help avoid unforeseen pitfalls, and lead to more robust conclusions; (b) developing adaptable conceptual and analytical models early was crucial to organizing our knowledge, guiding our study design, and analyzing our data; (c) catchment-wide processes that we did not monitor, or initially consider, had profound implications for interpreting our findings; and (d) using multiple analytical frameworks, with varying assumptions, led to clearer interpretation of findings than the use of a single framework alone. Broader integration of these guiding principles into monitoring studies, though potentially challenging, could lead to more scientifically defensible assessments of project effects.

Forecasting consequences of changing sea ice availability for Pacific walruses

USGS Publications Warehouse

Udevitz, Mark S.; Jay, Chadwick V.; Taylor, Rebecca; Fischbach, Anthony S.; Beatty, William S.; Noren, Shawn R.

2017-01-01

The accelerating rate of anthropogenic alteration and disturbance of environments has increased the need for forecasting effects of environmental change on fish and wildlife populations. Models linking projections of environmental change with behavioral responses and bioenergetic effects can provide a basis for these forecasts. There is particular interest in forecasting effects of projected reductions in sea ice availability on Pacific walruses (Odobenus rosmarus divergens). Declining extent of summer sea ice in the Chukchi Sea has caused Pacific walruses to increase use of coastal haulouts and decrease use of more productive offshore feeding areas. Such climate-induced changes in distribution and behavior could ultimately affect the status of the population. We developed behavioral models to relate changes in sea ice availability to adult female walrus movements and activity levels, and adapted previously developed bioenergetics models to relate those activity levels to energy requirements and the ability to meet those requirements. We then linked these models to general circulation model projections of future ice availability to forecast autumn body condition for female walruses during mid- and late-century time periods. Our results suggest that as sea ice becomes less available in the Chukchi Sea, female walruses will spend more time in the southwestern region of that sea, less time resting, and less time foraging. Median forecasted autumn body masses were 7–12% lower in future scenarios than during recent times, but posterior distributions broadly overlapped and median forecasted seasonal mass losses (15–34%) were comparable to seasonal mass losses routinely experienced by other pinnipeds. These seasonal reductions in body condition would be unlikely to result in demographic effects, but if walruses were unable to rebuild endogenous reserves while wintering in the Bering Sea, cumulative effects could have implications for reproduction and survival, ultimately affecting the status of the Pacific walrus population. Our approach provides a general framework for forecasting consequences of the broad range of environmental changes and anthropogenic disturbances that may affect bioenergetics through behavioral responses or changes in prey availability.

Modeling the epidemic of nonalcoholic fatty liver disease demonstrates an exponential increase in burden of disease

PubMed Central

Razavi, Homie; Loomba, Rohit; Younossi, Zobair; Sanyal, Arun J.

2017-01-01

Nonalcoholic fatty liver disease (NAFLD) and resulting nonalcoholic steatohepatitis (NASH) are highly prevalent in the United States, where they are a growing cause of cirrhosis and hepatocellular carcinoma (HCC) and increasingly an indicator for liver transplantation. A Markov model was used to forecast NAFLD disease progression. Incidence of NAFLD was based on historical and projected changes in adult prevalence of obesity and type 2 diabetes mellitus (DM). Assumptions were derived from published literature where available and validated using national surveillance data for incidence of NAFLD‐related HCC. Projected changes in NAFLD‐related cirrhosis, advanced liver disease, and liver‐related mortality were quantified through 2030. Prevalent NAFLD cases are forecasted to increase 21%, from 83.1 million (2015) to 100.9 million (2030), while prevalent NASH cases will increase 63% from 16.52 million to 27.00 million cases. Overall NAFLD prevalence among the adult population (aged ≥15 years) is projected at 33.5% in 2030, and the median age of the NAFLD population will increase from 50 to 55 years during 2015‐2030. In 2015, approximately 20% of NAFLD cases were classified as NASH, increasing to 27% by 2030, a reflection of both disease progression and an aging population. Incidence of decompensated cirrhosis will increase 168% to 105,430 cases by 2030, while incidence of HCC will increase by 137% to 12,240 cases. Liver deaths will increase 178% to an estimated 78,300 deaths in 2030. During 2015‐2030, there are projected to be nearly 800,000 excess liver deaths. Conclusion: With continued high rates of adult obesity and DM along with an aging population, NAFLD‐related liver disease and mortality will increase in the United States. Strategies to slow the growth of NAFLD cases and therapeutic options are necessary to mitigate disease burden. (Hepatology 2018;67:123‐133). PMID:28802062

Modeling the Present and Future Incidence of Pediatric Hand, Foot, and Mouth Disease Associated with Ambient Temperature in Mainland China.

PubMed

Zhao, Qi; Li, Shanshan; Cao, Wei; Liu, De-Li; Qian, Quan; Ren, Hongyan; Ding, Fan; Williams, Gail; Huxley, Rachel; Zhang, Wenyi; Guo, Yuming

2018-04-20

There is limited evidence about the association between ambient temperature and the incidence of pediatric hand, foot, and mouth disease (HFMD) nationwide in China. We examined the childhood temperature-HFMD associations across mainland China, and we projected the change in HFMD cases due to projected temperature change by the 2090s. Data on daily HFMD (children 0-14 y old) counts and weather were collected from 362 sites during 2009-2014. Daily temperature by the 2090s was downscaled under the Representative Concentration Pathway (RCP) 4.5 and 8.5 scenarios. Temperature-HFMD associations were quantified using a two-stage Poisson regression with a distributed lag nonlinear model. The impact of changes in temperature on the incidence of HFMD was estimated by combining the fitted temperature-HFMD associations with projected temperatures under each scenario, assuming a constant population structure. Sensitivity analyses were performed to assess the influence of primary model assumptions. During 2009-2014, >11 million HFMD cases were reported. In most regions, the temperature-HFMD association had an inverted U shape with a peak at approximately 20°C, but the association leveled off or continued to increase in the Inner Mongolia and Northeast regions. When estimates were pooled across all regions and the population size was held constant, the projected incidence of HFMD increased by 3.2% [95% empirical confidence interval (eCI): −13.5%, 20.0%] and 5.3% (95% eCI: −33.3%, 44.0%) by the 2090s under the RCP 4.5 and 8.5 scenarios, respectively. However, regional projections suggest that HFMD may decrease with climate change in temperate areas of central and eastern China. Our estimates suggest that the association between temperature and HFMD varies across China and that the future impact of climate change on HFMD incidence will vary as well. Other factors, including changes in the size of the population at risk (children 0-14 y old) will also influence future HFMD trends. https://doi.org/10.1289/EHP3062.

MoSeS: Modelling and Simulation for e-Social Science.

PubMed

Townend, Paul; Xu, Jie; Birkin, Mark; Turner, Andy; Wu, Belinda

2009-07-13

MoSeS (Modelling and Simulation for e-Social Science) is a research node of the National Centre for e-Social Science. MoSeS uses e-Science techniques to execute an events-driven model that simulates discrete demographic processes; this allows us to project the UK population 25 years into the future. This paper describes the architecture, simulation methodology and latest results obtained by MoSeS.

Assessing Ozone-Related Health Impacts under a Changing Climate

PubMed Central

Knowlton, Kim; Rosenthal, Joyce E.; Hogrefe, Christian; Lynn, Barry; Gaffin, Stuart; Goldberg, Richard; Rosenzweig, Cynthia; Civerolo, Kevin; Ku, Jia-Yeong; Kinney, Patrick L.

2004-01-01

Climate change may increase the frequency and intensity of ozone episodes in future summers in the United States. However, only recently have models become available that can assess the impact of climate change on O3 concentrations and health effects at regional and local scales that are relevant to adaptive planning. We developed and applied an integrated modeling framework to assess potential O3-related health impacts in future decades under a changing climate. The National Aeronautics and Space Administration–Goddard Institute for Space Studies global climate model at 4° × 5° resolution was linked to the Penn State/National Center for Atmospheric Research Mesoscale Model 5 and the Community Multiscale Air Quality atmospheric chemistry model at 36 km horizontal grid resolution to simulate hourly regional meteorology and O3 in five summers of the 2050s decade across the 31-county New York metropolitan region. We assessed changes in O3-related impacts on summer mortality resulting from climate change alone and with climate change superimposed on changes in O3 precursor emissions and population growth. Considering climate change alone, there was a median 4.5% increase in O3-related acute mortality across the 31 counties. Incorporating O3 precursor emission increases along with climate change yielded similar results. When population growth was factored into the projections, absolute impacts increased substantially. Counties with the highest percent increases in projected O3 mortality spread beyond the urban core into less densely populated suburban counties. This modeling framework provides a potentially useful new tool for assessing the health risks of climate change. PMID:15531442

Population pressure on coral atolls: trends and approaching limits.

PubMed

Rapaport, M

1990-09-01

Trends and approaching limits of population pressure on coral atolls is discussed by examining the atoll environment in terms of the physical geography, the production systems, and resource distribution. Atoll populations are grouped as dependent and independent, and demographic trends in population growth, migraiton, urbanization, and political dependency are reviewed. Examination of the carrying capacity includes a dynamic model, the influences of the West, and philopsophical considerations. The carrying capacity is the "maximal population supportable in a given area". Traditional models are criticized because of a lack in accounting for external linkages. The proposed model is dynamic and considers perceived needs and overseas linkages. It also explains regional disparities in population distribution, and provides a continuing model for population movement from outer islands to district centers and mainland areas. Because of increased expectations and perceived needs, there is a lower carrying capacity for outlying areas, and expanded capacity in district centers. This leads to urbanization, emigration, and carrying capacity overshot in regional and mainland areas. Policy intervention is necessary at the regional and island community level. Atolls, which are islands surrounding deep lagoons, exist in archipelagoes across the oceans, and are rich in aquatic life. The balance in this small land area with a vulnerable ecosystem may be easily disturbed by scarce water supplies, barren soils, rising sea levels in the future, hurricanes, and tsunamis. Traditionally, fisheries and horticulture (pit-taro, coconuts, and breadfruit) have sustained populations, but modern influences such as blasting, reef mining, new industrial technologies, population pressure, and urbanization threaten the balance. Population pressure, which has lead to pollution, epidemics, malnutrition, crime, social disintegration, and foreign dependence, is evidenced in the areas of Tuvalu, Kiribati, the Marshall Islands, and the Maldive Islands, independent islands. Other areas with low migration, low growth rates, and minimal urbanization include the Tokelau Islands, the Northern Cook Islands, the Tuamotu Archipelago, and the outer islands in the Federated States of Micronesia. Additional research is needed to identify and develop drought resistant and salt resistent varieties of trees, root crops, and other resources. Fresh water areas need protection from overland latrines and irrigation projects, and construction projects. Improvements are needed for regional cooperation and collaboration in industrial development. Tourism and the export industries yield income but produce urban problems. Addressing low growth areas with economic means alleviates spillover effects.

The Effect of Future Ambient Air Pollution on Human Premature Mortality to 2100 Using Output from the ACCMIP Model Ensemble

NASA Technical Reports Server (NTRS)

Silva, Raquel A.; West, J. Jason; Lamarque, Jean-Francois; Shindell, Drew T.; Collins, William J.; Dalsoren, Stig; Faluvegi, Greg; Folberth, Gerd; Horowitz, Larry W.; Nagashima, Tatsuya;

A log-linear model approach to estimation of population size using the line-transect sampling method

USGS Publications Warehouse

Anderson, D.R.; Burnham, K.P.; Crain, B.R.

1978-01-01

The technique of estimating wildlife population size and density using the belt or line-transect sampling method has been used in many past projects, such as the estimation of density of waterfowl nestling sites in marshes, and is being used currently in such areas as the assessment of Pacific porpoise stocks in regions of tuna fishing activity. A mathematical framework for line-transect methodology has only emerged in the last 5 yr. In the present article, we extend this mathematical framework to a line-transect estimator based upon a log-linear model approach.

Climate change overruns resilience conferred by temperature-dependent sex determination in sea turtles and threatens their survival.

PubMed

Santidrián Tomillo, Pilar; Genovart, Meritxell; Paladino, Frank V; Spotila, James R; Oro, Daniel

2015-08-01

Temperature-dependent sex determination (TSD) is the predominant form of environmental sex determination (ESD) in reptiles, but the adaptive significance of TSD in this group remains unclear. Additionally, the viability of species with TSD may be compromised as climate gets warmer. We simulated population responses in a turtle with TSD to increasing nest temperatures and compared the results to those of a virtual population with genotypic sex determination (GSD) and fixed sex ratios. Then, we assessed the effectiveness of TSD as a mechanism to maintain populations under climate change scenarios. TSD populations were more resilient to increased nest temperatures and mitigated the negative effects of high temperatures by increasing production of female offspring and therefore, future fecundity. That buffered the negative effect of temperature on the population growth. TSD provides an evolutionary advantage to sea turtles. However, this mechanism was only effective over a range of temperatures and will become inefficient as temperatures rise to levels projected by current climate change models. Projected global warming threatens survival of sea turtles, and the IPCC high gas concentration scenario may result in extirpation of the studied population in 50 years. © 2015 John Wiley & Sons Ltd.

Predicting 21st-century polar bear habitat distribution from global climate models

USGS Publications Warehouse

Durner, George M.; Douglas, David C.; Nielson, R.M.; Amstrup, Steven C.; McDonald, T.L.; Stirling, I.; Mauritzen, Mette; Born, E.W.; Wiig, O.; Deweaver, E.; Serreze, Mark C.; Belikov, Stanislav; Holland, M.M.; Maslanik, J.; Aars, Jon; Bailey, D.A.; Derocher, A.E.

2009-01-01

Projections of polar bear (Ursus maritimus) sea ice habitat distribution in the polar basin during the 21st century were developed to understand the consequences of anticipated sea ice reductions on polar bear populations. We used location data from satellitecollared polar bears and environmental data (e.g., bathymetry, distance to coastlines, and sea ice) collected from 1985 to 1995 to build resource selection functions (RSFs). RSFs described habitats that polar bears preferred in summer, autumn, winter, and spring. When applied to independent data from 1996 to 2006, the RSFs consistently identified habitats most frequently used by polar bears. We applied the RSFs to monthly maps of 21st-century sea ice concentration projected by 10 general circulation models (GCMs) used in the Intergovernmental Panel of Climate Change Fourth Assessment Report, under the A1B greenhouse gas forcing scenario. Despite variation in their projections, all GCMs indicated habitat losses in the polar basin during the 21st century. Losses in the highest-valued RSF habitat (optimal habitat) were greatest in the southern seas of the polar basin, especially the Chukchi and Barents seas, and least along the Arctic Ocean shores of Banks Island to northern Greenland. Mean loss of optimal polar bear habitat was greatest during summer; from an observed 1.0 million km2 in 1985-1995 (baseline) to a projected multi-model mean of 0.32 million km2 in 2090-2099 (-68% change). Projected winter losses of polar bear habitat were less: from 1.7 million km2 in 1985-1995 to 1.4 million km2 in 2090-2099 (-17% change). Habitat losses based on GCM multi-model means may be conservative; simulated rates of habitat loss during 1985-2006 from many GCMs were less than the actual observed rates of loss. Although a reduction in the total amount of optimal habitat will likely reduce polar bear populations, exact relationships between habitat losses and population demographics remain unknown. Density and energetic effects may become important as polar bears make long-distance annual migrations from traditional winter ranges to remnant high-latitude summer sea ice. These impacts will likely affect specific sex and age groups differently and may ultimately preclude bears from seasonally returning to their traditional ranges.

Projections of annual rainfall and surface temperature from CMIP5 models over the BIMSTEC countries

NASA Astrophysics Data System (ADS)

Pattnayak, K. C.; Kar, S. C.; Dalal, Mamta; Pattnayak, R. K.

2017-05-01

Bay of Bengal Initiative for Multi-Sectoral Technical and Economic Cooperation (BIMSTEC) comprising Bangladesh, Bhutan, India, Myanmar, Nepal, Sri Lanka and Thailand brings together 21% of the world population. Thus the impact of climate change in this region is a major concern for all. To study the climate change, fifth phase of Climate Model Inter-comparison Project (CMIP5) models have been used to project the climate for the 21st century under the Representative Concentration Pathways (RCPs) 4.5 and 8.5 over the BIMSTEC countries for the period 1901 to 2100 (initial 105 years are historical period and the later 95 years are projected period). Climate change in the projected period has been examined with respect to the historical period. In order to validate the models, the mean annual rainfall has been compared with observations from multiple sources and temperature has been compared with the data from Climatic Research Unit (CRU) during the historical period. Comparison reveals that ensemble mean of the models is able to represent the observed spatial distribution of rainfall and temperature over the BIMSTEC countries. Therefore, data from these models may be used to study the future changes in the 21st century. Four out of six models show that the rainfall over India, Thailand and Myanmar has decreasing trend and Bangladesh, Bhutan, Nepal and Sri Lanka show an increasing trend in both the RCP scenarios. In case of temperature, all the models show an increasing trend over all the BIMSTEC countries in both the scenarios, however, the rate of increase is relatively less over Sri Lanka than the other countries. The rate of increase/decrease in rainfall and temperature are relatively more in RCP8.5 than RCP4.5 over all these countries. Inter-model comparison show that there are uncertainties within the CMIP5 model projections. More similar studies are required to be done for better understanding the model uncertainties in climate projections over this region.

Tuning stochastic matrix models with hydrologic data to predict the population dynamics of a riverine fish

USGS Publications Warehouse

Sakaris, P.C.; Irwin, E.R.

2010-01-01

We developed stochastic matrix models to evaluate the effects of hydrologic alteration and variable mortality on the population dynamics of a lotie fish in a regulated river system. Models were applied to a representative lotic fish species, the flathead catfish (Pylodictis olivaris), for which two populations were examined: a native population from a regulated reach of the Coosa River (Alabama, USA) and an introduced population from an unregulated section of the Ocmulgee River (Georgia, USA). Size-classified matrix models were constructed for both populations, and residuals from catch-curve regressions were used as indices of year class strength (i.e., recruitment). A multiple regression model indicated that recruitment of flathead catfish in the Coosa River was positively related to the frequency of spring pulses between 283 and 566 m3/s. For the Ocmulgee River population, multiple regression models indicated that year class strength was negatively related to mean March discharge and positively related to June low flow. When the Coosa population was modeled to experience five consecutive years of favorable hydrologic conditions during a 50-year projection period, it exhibited a substantial spike in size and increased at an overall 0.2% annual rate. When modeled to experience five years of unfavorable hydrologic conditions, the Coosa population initially exhibited a decrease in size but later stabilized and increased at a 0.4% annual rate following the decline. When the Ocmulgee River population was modeled to experience five years of favorable conditions, it exhibited a substantial spike in size and increased at an overall 0.4% annual rate. After the Ocmulgee population experienced five years of unfavorable conditions, a sharp decline in population size was predicted. However, the population quickly recovered, with population size increasing at a 0.3% annual rate following the decline. In general, stochastic population growth in the Ocmulgee River was more erratic and variable than population growth in the Coosa River. We encourage ecologists to develop similar models for other lotic species, particularly in regulated river systems. Successful management of fish populations in regulated systems requires that we are able to predict how hydrology affects recruitment and will ultimately influence the population dynamics of fishes. ?? 2010 by the Ecological Society of America.

DynaPop-X: A population dynamics model applied to spatio-temporal exposure assessment - Implementation aspects from the CRISMA project

NASA Astrophysics Data System (ADS)

Aubrecht, Christoph; Steinnocher, Klaus; Humer, Heinrich; Huber, Hermann

2014-05-01

In the context of proactive disaster risk as well as immediate situational crisis management knowledge of locational social aspects in terms of spatio-temporal population distribution dynamics is considered among the most important factors for disaster impact minimization (Aubrecht et al., 2013a). This applies to both the pre-event stage for designing appropriate preparedness measures and to acute crisis situations when an event chain actually unfolds for efficient situation-aware response. The presented DynaPop population dynamics model is developed at the interface of those interlinked crisis stages and aims at providing basic input for social impact evaluation and decision support in crisis management. The model provides the starting point for assessing population exposure dynamics - thus here labeled as DynaPop-X - which can either be applied in a sense of illustrating the changing locations and numbers of affected people at different stages during an event or as ex-ante estimations of probable and maximum expected clusters of affected population (Aubrecht et al., 2013b; Freire & Aubrecht, 2012). DynaPop is implemented via a gridded spatial disaggregation approach and integrates previous efforts on spatio-temporal modeling that account for various aspects of population dynamics such as human mobility and activity patterns that are particularly relevant in picturing the highly dynamic daytime situation (Ahola et al., 2007; Bhaduri, 2008; Cockings et al., 2010). We will present ongoing developments particularly focusing on the implementation logic of the model using the emikat software tool, a data management system initially designed for inventorying and analysis of spatially resolved regional air pollutant emission scenarios. This study was performed in the framework of the EU CRISMA project. CRISMA is funded from the European Community's Seventh Framework Programme FP7/2007-2013 under grant agreement no. 284552. REFERENCES Ahola, T., Virrantaus, K., Krisp, J.K., Hunter, G.J. (2007) A spatio-temporal population model to support risk assessment and damage analysis for decision-making. International Journal of Geographical Information Science, 21(8), 935-953. Aubrecht, C., Fuchs, S., Neuhold, C. (2013a) Spatio-temporal aspects and dimensions in integrated disaster risk management. Natural Hazards, 68(3), 1205-1216. Aubrecht, C., Özceylan, D., Steinnocher, K., Freire, S. (2013b) Multi-level geospatial modeling of human exposure patterns and vulnerability indicators. Natural Hazards, 68(1), 147-163. Bhaduri, B. (2008) Population distribution during the day. In S. Shekhar & X. Hui, eds., Encyclopedia of GIS. Springer US, 880-885. Cockings, S., Martin, D. & Leung, S. (2010) Population 24/7: building space-time specific population surface models. In M. Haklay, J. Morley, & H. Rahemtulla, eds., Proceedings of the GIS Research UK 18th Annual conference. GISRUK 2010. London, UK, 41-47. Freire, S., Aubrecht, C. (2012) Integrating population dynamics into mapping human exposure to seismic hazard. Natural Hazards and Earth System Sciences, 12(11), 3533-3543.

Sightability adjustment methods for aerial surveys of wildlife populations

USGS Publications Warehouse

Steinhorst, R.K.; Samuel, M.D.

1989-01-01

Aerial surveys are routinely conducted to estimate the abundance of wildlife species and the rate of population change. However, sightability of animal groups is acknowledged as a significant source of bias in these estimates. Recent research has focused on the development of sightability models to predict the probability of sighting groups under various conditions. Given such models, we show how sightability can be incorporated into the estimator of population size as a probability of response using standard results from sample surveys. We develop formulas for the cases where the sighting probability must be estimated. An example, using data from a helicopter survey of moose in Alberta (Jacobson, Alberta Oil Sands Research Project Report, 1976), is given to illustrate the technique.

Assessment of Medical Risks and Optimization of their Management using Integrated Medical Model

NASA Technical Reports Server (NTRS)

Fitts, Mary A.; Madurai, Siram; Butler, Doug; Kerstman, Eric; Risin, Diana

2008-01-01

The Integrated Medical Model (IMM) Project is a software-based technique that will identify and quantify the medical needs and health risks of exploration crew members during space flight and evaluate the effectiveness of potential mitigation strategies. The IMM Project employs an evidence-based approach that will quantify probability and consequences of defined in-flight medical risks, mitigation strategies, and tactics to optimize crew member health. Using stochastic techniques, the IMM will ultimately inform decision makers at both programmatic and institutional levels and will enable objective assessment of crew health and optimization of mission success using data from relevant cohort populations and from the astronaut population. The objectives of the project include: 1) identification and documentation of conditions that may occur during exploration missions (Baseline Medical Conditions List [BMCL), 2) assessment of the likelihood of conditions in the BMCL occurring during exploration missions (incidence rate), 3) determination of the risk associated with these conditions and quantify in terms of end states (Loss of Crew, Loss of Mission, Evacuation), 4) optimization of in-flight hardware mass, volume, power, bandwidth and cost for a given level of risk or uncertainty, and .. validation of the methodologies used.

The Atlanta Urban Heat Island Mitigation and Air Quality Modeling Project: How High-Resoution Remote Sensing Data Can Improve Air Quality Models

NASA Technical Reports Server (NTRS)

Quattrochi, Dale A.; Estes, Maurice G., Jr.; Crosson, William L.; Khan, Maudood N.

2006-01-01

The Atlanta Urban Heat Island and Air Quality Project had its genesis in Project ATLANTA (ATlanta Land use Analysis: Temperature and Air quality) that began in 1996. Project ATLANTA examined how high-spatial resolution thermal remote sensing data could be used to derive better measurements of the Urban Heat Island effect over Atlanta. We have explored how these thermal remote sensing, as well as other imaged datasets, can be used to better characterize the urban landscape for improved air quality modeling over the Atlanta area. For the air quality modeling project, the National Land Cover Dataset and the local scale Landpro99 dataset at 30m spatial resolutions have been used to derive land use/land cover characteristics for input into the MM5 mesoscale meteorological model that is one of the foundations for the Community Multiscale Air Quality (CMAQ) model to assess how these data can improve output from CMAQ. Additionally, land use changes to 2030 have been predicted using a Spatial Growth Model (SGM). SGM simulates growth around a region using population, employment and travel demand forecasts. Air quality modeling simulations were conducted using both current and future land cover. Meteorological modeling simulations indicate a 0.5 C increase in daily maximum air temperatures by 2030. Air quality modeling simulations show substantial differences in relative contributions of individual atmospheric pollutant constituents as a result of land cover change. Enhanced boundary layer mixing over the city tends to offset the increase in ozone concentration expected due to higher surface temperatures as a result of urbanization.

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

USGS Publications Warehouse

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.

Conservation biology for suites of species: Demographic modeling for Pacific island kingfishers

USGS Publications Warehouse

Kesler, D.C.; Haig, S.M.

2007-01-01

Conservation practitioners frequently extrapolate data from single-species investigations when managing critically endangered populations. However, few researchers initiate work with the intent of making findings useful to conservation efforts for other species. We presented and explored the concept of conducting conservation-oriented research for suites of geographically separated populations with similar natural histories, resource needs, and extinction threats. An example was provided in the form of an investigation into the population demography of endangered Micronesian kingfishers (Todiramphus cinnamominus). We provided the first demographic parameter estimates for any of the 12 endangered Pacific Todiramphus species, and used results to develop a population projection matrix model for management throughout the insular Pacific. Further, we used the model for elasticity and simulation analyses with demographic values that randomly varied across ranges that might characterize congener populations. Results from elasticity and simulation analyses indicated that changes in breeding adult survival exerted the greatest magnitude of influence on population dynamics. However, changes in nestling survival were more consistently correlated with population dynamics as demographic rates were randomly altered. We concluded that conservation practitioners working with endangered Pacific kingfishers should primarily focus efforts on factors affecting nestling and breeder survival, and secondarily address fledgling juveniles and helpers. Further, we described how the generalized base model might be changed to focus on individual populations and discussed the potential application of multi-species models to other conservation situations. ?? 2007 Elsevier Ltd. All rights reserved.

Modeling social norms and social influence in obesity

PubMed Central

Shoham, David A.; Hammond, Ross; Rahmandad, Hazhir; Wang, Youfa; Hovmand, Peter

2015-01-01

The worldwide increase in obesity has led to changes in what is considered “normal” or desirable weight, especially among populations at higher risk. We show that social norms are key to understanding the obesity epidemic, and that social influence mechanisms provide a necessary linkage between individual obesity-related behaviors and population-level characteristics. Because influence mechanisms cannot be directly observed, we show how three complex systems tools may be used to gain insights into observed epidemiologic patterns: social network analysis, agent-based modeling, and systems dynamics modeling. However, simulation and mathematical modeling approaches raise questions regarding acceptance of findings, especially among policy makers. Nevertheless, we point to modeling successes in obesity and other fields, including the NIH-funded National Collaborative on Childhood Obesity Research (NCCOR) Envison project. PMID:26576335

Toward Dynamic Ocean Management: Fisheries assessment and climate projections informed by community developed habitat models based on dynamic coastal oceanography

NASA Astrophysics Data System (ADS)

Kohut, J. T.; Manderson, J.; Palamara, L. J.; Saba, V. S.; Saba, G.; Hare, J. A.; Curchitser, E. N.; Moore, P.; Seibel, B.; DiDomenico, G.

2016-12-01

Through a multidisciplinary study group of experts in marine ecology, physical oceanography and stock assessment from the fishing industry, government and academia we developed a method to explicitly account for shifting habitat distributions in fish population assessments. We used data from field surveys throughout the Northwest Atlantic Ocean to develop a parametric thermal niche model for an important short-lived pelagic forage fish, Atlantic Butterfish. This niche model was coupled to a hindcast of daily bottom water temperature derived from a regional numerical ocean model in order to project daily thermal habitat suitability over the last 40 years. This ecological hindcast was used to estimate the proportion of thermal habitat suitability available on the U.S. Northeast Shelf that was sampled on fishery-independent surveys, accounting for the relative motions of thermal habitat and the trajectory of sampling on the survey. The method and habitat based estimates of availability was integrated into the catchability estimate used to scale population size in the butterfish stock assessment model accepted by the reviewers of the 59th NEFSC stock assessment review, as well as the mid-Atlantic Council's Scientific and Statistical Committee. The contribution of the availability estimate (along with an estimate of detectability) allowed for the development of fishery reference points, a change in stock status from unknown to known, and the establishment of a directed fishery with an allocation of 20,000 metric tons of quota. This presentation will describe how a community based workgroup utilized ocean observing technologies combined with ocean models to better understand the physical ocean that structures marine ecosystems. Using these approaches we will discuss opportunities to inform ecological hindcasts and climate projections with mechanistic models that link species-specific physiology to climate-based thermal scenarios.

Toward Dynamic Ocean Management: Fisheries assessment and climate projections informed by community developed habitat models based on dynamic coastal oceanography

NASA Astrophysics Data System (ADS)

Kohut, J. T.; Manderson, J.; Palamara, L. J.; Saba, V. S.; Saba, G.; Hare, J. A.; Curchitser, E. N.; Moore, P.; Seibel, B.; DiDomenico, G.

2016-02-01

Through a multidisciplinary study group of experts in marine ecology, physical oceanography and stock assessment from the fishing industry, government and academia we developed a method to explicitly account for shifting habitat distributions in fish population assessments. We used data from field surveys throughout the Northwest Atlantic Ocean to develop a parametric thermal niche model for an important short-lived pelagic forage fish, Atlantic Butterfish. This niche model was coupled to a hindcast of daily bottom water temperature derived from a regional numerical ocean model in order to project daily thermal habitat suitability over the last 40 years. This ecological hindcast was used to estimate the proportion of thermal habitat suitability available on the U.S. Northeast Shelf that was sampled on fishery-independent surveys, accounting for the relative motions of thermal habitat and the trajectory of sampling on the survey. The method and habitat based estimates of availability was integrated into the catchability estimate used to scale population size in the butterfish stock assessment model accepted by the reviewers of the 59th NEFSC stock assessment review, as well as the mid-Atlantic Council's Scientific and Statistical Committee. The contribution of the availability estimate (along with an estimate of detectability) allowed for the development of fishery reference points, a change in stock status from unknown to known, and the establishment of a directed fishery with an allocation of 20,000 metric tons of quota. This presentation will describe how a community based workgroup utilized ocean observing technologies combined with ocean models to better understand the physical ocean that structures marine ecosystems. Using these approaches we will discuss opportunities to inform ecological hindcasts and climate projections with mechanistic models that link species-specific physiology to climate-based thermal scenarios.

The influence of lightning activity and anthropogenic factors on large-scale characteristics of natural fires

NASA Astrophysics Data System (ADS)

Eliseev, A. V.; Mokhov, I. I.; Chernokulsky, A. V.

2017-01-01

A module for simulating of natural fires (NFs) in the climate model of the A.M. Obukhov Institute of Atmospheric Physics, Russian Academy of Sciences (IAP RAS CM), is extended with respect to the influence of lightning activity and population density on the ignition frequency and fire suppression. The IAP RAS CM is used to perform numerical experiments in accordance with the conditions of the project that intercompares climate models, CMIP5 (Coupled Models Intercomparison Project, phase 5). The frequency of lightning flashes was assigned in accordance with the LIS/OTD satellite data. In the calculations performed, anthropogenic ignitions play an important role in NF occurrences, except for regions at subpolar latitudes and, to a lesser degree, tropical and subtropical regions. Taking into account the dependence of fire frequency on lightning activity and population density intensifies the influence of characteristics of natural fires on the climate changes in tropics and subtropics as compared to the version of the IAP RAS CM that does not take the influence of ignition sources on the large-scale characteristics of NFs into consideration.

Combining dispersal, landscape connectivity and habitat suitability to assess climate-induced changes in the distribution of Cunningham’s skink, Egernia cunninghami

PubMed Central

Stow, Adam J.; Baumgartner, John B.; Beaumont, Linda J.

2017-01-01

The ability of species to track their climate niche is dependent on their dispersal potential and the connectivity of the landscape matrix linking current and future suitable habitat. However, studies modeling climate-driven range shifts rarely address the movement of species across landscapes realistically, often assuming “unlimited” or “no” dispersal. Here, we incorporate dispersal rate and landscape connectivity with a species distribution model (Maxent) to assess the extent to which the Cunningham’s skink (Egernia cunninghami) may be capable of tracking spatial shifts in suitable habitat as climate changes. Our model was projected onto four contrasting, but equally plausible, scenarios describing futures that are (relative to now) hot/wet, warm/dry, hot/with similar precipitation and warm/wet, at six time horizons with decadal intervals (2020–2070) and at two spatial resolutions: 1 km and 250 m. The size of suitable habitat was projected to decline 23–63% at 1 km and 26–64% at 250 m, by 2070. Combining Maxent output with the dispersal rate of the species and connectivity of the intervening landscape matrix showed that most current populations in regions projected to become unsuitable in the medium to long term, will be unable to shift the distance necessary to reach suitable habitat. In particular, numerous populations currently inhabiting the trailing edge of the species’ range are highly unlikely to be able to disperse fast enough to track climate change. Unless these populations are capable of adaptation they are likely to be extirpated. We note, however, that the core of the species distribution remains suitable across the broad spectrum of climate scenarios considered. Our findings highlight challenges faced by philopatric species and the importance of adaptation for the persistence of peripheral populations under climate change. PMID:28873398

Population viability of the Snake River chinook salmon (Oncorhynchus tshawytscha)

USGS Publications Warehouse

Emlen, John M.

1995-01-01

In the presence of historical data, population viability models of intermediate complexity can be parameterized and utilized to project the consequences of various management actions for endangered species. A general stochastic population dynamics model with density feedback, age structure, and autocorrelated environmental fluctuations was constructed and parameterized for best fit over 36 years of spring chinook salmon (Oncorhynchus tshawytscha) redd count data in five Idaho index streams. Simulations indicate that persistence of the Snake River spring chinook salmon population depends primarily on density-independent mortality. Improvement of rearing habitat, predator control, reduced fishing pressure, and improved dam passage all would alleviate density-independent mortality. The current value of the Ricker α should provide for a continuation of the status quo. A recovery of the population to 1957–1961 levels within 100 years would require an approximately 75% increase in survival and (or) fecundity. Manipulations of the Ricker β are likely to have little or no effect on persistence versus extinction, but considerable influence on population size.

The projection of a test genome onto a reference population and applications to humans and archaic hominins.

PubMed

Yang, Melinda A; Harris, Kelley; Slatkin, Montgomery

2014-12-01

We introduce a method for comparing a test genome with numerous genomes from a reference population. Sites in the test genome are given a weight, w, that depends on the allele frequency, x, in the reference population. The projection of the test genome onto the reference population is the average weight for each x, [Formula: see text]. The weight is assigned in such a way that, if the test genome is a random sample from the reference population, then [Formula: see text]. Using analytic theory, numerical analysis, and simulations, we show how the projection depends on the time of population splitting, the history of admixture, and changes in past population size. The projection is sensitive to small amounts of past admixture, the direction of admixture, and admixture from a population not sampled (a ghost population). We compute the projections of several human and two archaic genomes onto three reference populations from the 1000 Genomes project-Europeans, Han Chinese, and Yoruba-and discuss the consistency of our analysis with previously published results for European and Yoruba demographic history. Including higher amounts of admixture between Europeans and Yoruba soon after their separation and low amounts of admixture more recently can resolve discrepancies between the projections and demographic inferences from some previous studies. Copyright © 2014 by the Genetics Society of America.

Health Benefits of Reducing Sugar-Sweetened Beverage Intake in High Risk Populations of California: Results from the Cardiovascular Disease (CVD) Policy Model

PubMed Central

Mekonnen, Tekeshe A.; Odden, Michelle C.; Coxson, Pamela G.; Guzman, David; Lightwood, James; Wang, Y. Claire; Bibbins-Domingo, Kirsten

2013-01-01

Background Consumption of sugar-sweetened beverage (SSB) has risen over the past two decades, with over 10 million Californians drinking one or more SSB per day. High SSB intake is associated with risk of type 2 diabetes, obesity, hypertension, and coronary heart disease (CHD). Reduction of SSB intake and the potential impact on health outcomes in California and among racial, ethnic, and low-income sub-groups has not been quantified. Methods We projected the impact of reduced SSB consumption on health outcomes among all Californians and California subpopulations from 2013 to 2022. We used the CVD Policy Model – CA, an established computer simulation of diabetes and heart disease adapted to California. We modeled a reduction in SSB intake by 10–20% as has been projected to result from proposed penny-per-ounce excise tax on SSB and modeled varying effects of this reduction on health parameters including body mass index, blood pressure, and diabetes risk. We projected avoided cases of diabetes and CHD, and associated health care cost savings in 2012 US dollars. Results Over the next decade, a 10–20% SSB consumption reduction is projected to result in a 1.8–3.4% decline in the new cases of diabetes and an additional drop of 0.5–1% in incident CHD cases and 0.5–0.9% in total myocardial infarctions. The greatest reductions are expected in African Americans, Mexican Americans, and those with limited income regardless of race and ethnicity. This reduction in SSB consumption is projected to yield $320–620 million in medical cost savings associated with diabetes cases averted and an additional savings of $14–27 million in diabetes-related CHD costs avoided. Conclusions A reduction of SSB consumption could yield substantial population health benefits and cost savings for California. In particular, racial, ethnic, and low-income subgroups of California could reap the greatest health benefits. PMID:24349119

Projecting Future Urbanization with Prescott College's Spatial Growth Model to Promote Environmental Sustainability and Smart Growth, A Case Study in Atlanta, Georgia

NASA Technical Reports Server (NTRS)

Estes, Maurice G., Jr.; Crosson, William; Limaye, Ashutosh; Johnson, Hoyt; Quattrochi, Dale; Lapenta, William; Khan, Maudood

2006-01-01

Planning is an integral element of good management and necessary to anticipate events not merely respond to them. Projecting the quantity and spatial distribution of urban growth is essential to effectively plan for the delivery of city services and to evaluate potential environmental impacts. The major drivers of growth in large urban areas are increasing population, employment opportunities, and quality of life attractors such as a favorable climate and recreation opportunities. The spatial distribution of urban growth is dictated by the amount and location of developable land, topography, energy and water resources, transportation network, climate change, and the existing land use configuration. The Atlanta region is growing very rapidly both in population and the consumption of forestland or low-density residential development. Air pollution and water availability are significant ongoing environmental issues. The Prescott Spatial Growth Model (SGM) was used to make growth projections for the metropolitan Atlanta region to 2010,2020 and 2030 and results used for environmental assessment in both business as usual and smart growth scenarios. The Prescott SGM is a tool that uses an ESRI ArcView extension and can be applied at the parcel level or more coarse spatial scales and can accommodate a wide range of user inputs to develop any number of growth rules each of which can be weighted depending on growth assumptions. These projections were used in conjunction with meteorological and air quality models to evaluate future environmental impacts. This presentation will focus on the application of the SGM to the 13-County Atlanta Regional Commission planning jurisdiction as a case study. The SGM will be described, including how rule sets are developed and the decision process for allocation of future development to available land use categories. Data inputs required to effectively run the model will be discussed. Spatial growth projections for ten, twenty, and thirty year planning horizons will be presented and results discussed, including regional climate and air quality impacts.

The Evolving Urban Community and Military Installations: A Dynamic Spatial Decision Support System for Sustainable Military Communities

DTIC Science & Technology

2007-01-01

focus on identifying growth by income and housing costs. These, and other models are focused on the city itself and deal with growth over the course...2. This model employs a set of econometric models to project future population, household, and employment. The landscape is gridded into one... model in LEAM (LEAMecon) forecasts changes in output, employment and income over time based on changes in the market, technology, productivity and

Frequency-dependent population dynamics: effect of sex ratio and mating system on the elasticity of population growth rate.

PubMed

Haridas, C V; Eager, Eric Alan; Rebarber, Richard; Tenhumberg, Brigitte

2014-11-01

When vital rates depend on population structure (e.g., relative frequencies of males or females), an important question is how the long-term population growth rate λ responds to changes in rates. For instance, availability of mates may depend on the sex ratio of the population and hence reproductive rates could be frequency-dependent. In such cases change in any vital rate alters the structure, which in turn, affect frequency-dependent rates. We show that the elasticity of λ to a rate is the sum of (i) the effect of the linear change in the rate and (ii) the effect of nonlinear changes in frequency-dependent rates. The first component is always positive and is the classical elasticity in density-independent models obtained directly from the population projection matrix. The second component can be positive or negative and is absent in density-independent models. We explicitly express each component of the elasticity as a function of vital rates, eigenvalues and eigenvectors of the population projection matrix. We apply this result to a two-sex model, where male and female fertilities depend on adult sex ratio α (ratio of females to males) and the mating system (e.g., polygyny) through a harmonic mating function. We show that the nonlinear component of elasticity to a survival rate is negligible only when the average number of mates (per male) is close to α. In a strictly monogamous species, elasticity to female survival is larger than elasticity to male survival when α<1 (less females). In a polygynous species, elasticity to female survival can be larger than that of male survival even when sex ratio is female biased. Our results show how demography and mating system together determine the response to selection on sex-specific vital rates. Copyright © 2014 Elsevier Inc. All rights reserved.

Projected health and economic impact of rotavirus vaccination in GAVI-eligible countries: 2011-2030.

PubMed

Atherly, Deborah E; Lewis, Kristen D C; Tate, Jacqueline; Parashar, Umesh D; Rheingans, Richard D

2012-04-27

Rotavirus is the leading cause of diarrheal disease in children under 5 years of age. It is responsible for more than 450,000 deaths each year, with more than 90% of these deaths occurring in low-resource countries eligible for support by the GAVI Alliance. Significant efforts made by the Alliance and its partners are providing countries with the opportunity to introduce rotavirus vaccines into their national immunization programs, to help prevent childhood illness and death. We projected the cost-effectiveness and health impact of rotavirus vaccines in GAVI-eligible countries, to assist decision makers in prioritizing resources to achieve the greatest health benefits for their populations. A decision-analytic model was used to project the health outcomes and direct costs of a birth cohort in the target population, with and without a rotavirus vaccine. Current data on disease burden, vaccine efficacy, immunization rates, and costs were used in the model. Vaccination in GAVI-eligible countries would prevent 2.46 million childhood deaths and 83 million disability-adjusted life years (DALYs) from 2011 to 2030, with annual reductions of 180,000 childhood deaths at peak vaccine uptake. The cost per DALY averted is $42 for all GAVI countries combined, over the entire period. Rotavirus vaccination would be considered very cost-effective for the entire cohort of GAVI countries, and in each country individually, as cost-effectiveness ratios are less than the gross domestic product (GDP) per capita. Vaccination is most cost-effective and has the greatest impact in regions with high rotavirus mortality. Rotavirus vaccination in GAVI-eligible countries is very cost-effective and is projected to substantially reduce childhood mortality in this population. Copyright © 2012. Published by Elsevier Ltd.

Impact of climate change on ozone-related mortality and morbidity in Europe.

PubMed

Orru, Hans; Andersson, Camilla; Ebi, Kristie L; Langner, Joakim; Aström, Christofer; Forsberg, Bertil

2013-02-01

Ozone is a highly oxidative pollutant formed from precursors in the presence of sunlight, associated with respiratory morbidity and mortality. All else being equal, concentrations of ground-level ozone are expected to increase due to climate change. Ozone-related health impacts under a changing climate are projected using emission scenarios, models and epidemiological data. European ozone concentrations are modelled with the model of atmospheric transport and chemistry (MATCH)-RCA3 (50×50 km). Projections from two climate models, ECHAM4 and HadCM3, are applied under greenhouse gas emission scenarios A2 and A1B, respectively. We applied a European-wide exposure-response function to gridded population data and country-specific baseline mortality and morbidity. Comparing the current situation (1990-2009) with the baseline period (1961-1990), the largest increase in ozone-associated mortality and morbidity due to climate change (4-5%) have occurred in Belgium, Ireland, the Netherlands and the UK. Comparing the baseline period and the future periods (2021-2050 and 2041-2060), much larger increases in ozone-related mortality and morbidity are projected for Belgium, France, Spain and Portugal, with the impact being stronger using the climate projection from ECHAM4 (A2). However, in Nordic and Baltic countries the same magnitude of decrease is projected. The current study suggests that projected effects of climate change on ozone concentrations could differentially influence mortality and morbidity across Europe.

METABOLIC RATE MODELS AND THE SUBSTITUTABILITY OF PREDATOR POPULATIONS. (R825795)

EPA Science Inventory

The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...

Accommodating environmental variation in population models: metaphysiological biomass loss accounting.

PubMed

Owen-Smith, Norman

2011-07-01

1. There is a pressing need for population models that can reliably predict responses to changing environmental conditions and diagnose the causes of variation in abundance in space as well as through time. In this 'how to' article, it is outlined how standard population models can be modified to accommodate environmental variation in a heuristically conducive way. This approach is based on metaphysiological modelling concepts linking populations within food web contexts and underlying behaviour governing resource selection. Using population biomass as the currency, population changes can be considered at fine temporal scales taking into account seasonal variation. Density feedbacks are generated through the seasonal depression of resources even in the absence of interference competition. 2. Examples described include (i) metaphysiological modifications of Lotka-Volterra equations for coupled consumer-resource dynamics, accommodating seasonal variation in resource quality as well as availability, resource-dependent mortality and additive predation, (ii) spatial variation in habitat suitability evident from the population abundance attained, taking into account resource heterogeneity and consumer choice using empirical data, (iii) accommodating population structure through the variable sensitivity of life-history stages to resource deficiencies, affecting susceptibility to oscillatory dynamics and (iv) expansion of density-dependent equations to accommodate various biomass losses reducing population growth rate below its potential, including reductions in reproductive outputs. Supporting computational code and parameter values are provided. 3. The essential features of metaphysiological population models include (i) the biomass currency enabling within-year dynamics to be represented appropriately, (ii) distinguishing various processes reducing population growth below its potential, (iii) structural consistency in the representation of interacting populations and (iv) capacity to accommodate environmental variation in space as well as through time. Biomass dynamics provide a common currency linking behavioural, population and food web ecology. 4. Metaphysiological biomass loss accounting provides a conceptual framework more conducive for projecting and interpreting the population consequences of climatic shifts and human transformations of habitats than standard modelling approaches. © 2011 The Author. Journal of Animal Ecology © 2011 British Ecological Society.

Projecting the Local Impacts of Climate Change on a Central American Montane Avian Community

NASA Technical Reports Server (NTRS)

Gasner, Matthew R.; Jankowski, Jill E.; Ciecka, Anna L.; Kyle, Keiller O.; Rabenold, Kerry N.

2010-01-01

Significant changes in the climates of Central America are expected over the next century. Lowland rainforests harbor high alpha diversity on local scales (<1 km2), yet montane landscapes often support higher beta diversity on 10-100 km2 scales. Climate change will likely disrupt the altitudinal zonation of montane communities that produces such landscape diversity. Projections of biotic response to climate change have often used broad-scale modelling of geographical ranges, but understanding likely impacts on population viability is also necessary for anticipating local and global extinctions. We model species abundances and estimate range shifts for birds in the Tilaran Mountains of Costa Rica, asking whether projected changes in temperature and rainfall could be sufficient to imperil high-elevation endemics and whether these variables will likely impact communities similarly. We find that nearly half of 77 forest bird species can be expected to decline in the next century. Almost half of species projected to decline are endemic to Central America, and seven of eight species projected to become locally extinct are endemic to the highlands of Costa Rica and Panam . Logistic-regression modelling of distributions and similarity in projections produced by temperature and rainfall models suggest that changes in both variables will be important. Although these projections are probably conservative because they do not explicitly incorporate biological or climate variable interactions, they provide a starting point for incorporating more realistic biological complexity into community-change models. Prudent conservation planning for tropical mountains should focus on regions with room for altitudinal reorganization of communities comprised of ecological specialists.

Land Cover Applications, Landscape Dynamics, and Global Change

USGS Publications Warehouse

Tieszen, Larry L.

2007-01-01

The Land Cover Applications, Landscape Dynamics, and Global Change project at U.S. Geological Survey (USGS) Center for Earth Resources Observation and Science (EROS) seeks to integrate remote sensing and simulation models to better understand and seek solutions to national and global issues. Modeling processes related to population impacts, natural resource management, climate change, invasive species, land use changes, energy development, and climate mitigation all pose significant scientific opportunities. The project activities use remotely sensed data to support spatial monitoring, provide sensitivity analyses across landscapes and large regions, and make the data and results available on the Internet with data access and distribution, decision support systems, and on-line modeling. Applications support sustainable natural resource use, carbon cycle science, biodiversity conservation, climate change mitigation, and robust simulation modeling approaches that evaluate ecosystem and landscape dynamics.

An aerial sightability model for estimating ferruginous hawk population size

USGS Publications Warehouse

Ayers, L.W.; Anderson, S.H.

1999-01-01

Most raptor aerial survey projects have focused on numeric description of visibility bias without identifying the contributing factors or developing predictive models to account for imperfect detection rates. Our goal was to develop a sightability model for nesting ferruginous hawks (Buteo regalis) that could account for nests missed during aerial surveys and provide more accurate population estimates. Eighteen observers, all unfamiliar with nest locations in a known population, searched for nests within 300 m of flight transects via a Maule fixed-wing aircraft. Flight variables tested for their influence on nest-detection rates included aircraft speed, height, direction of travel, time of day, light condition, distance to nest, and observer experience level. Nest variables included status (active vs. inactive), condition (i.e., excellent, good, fair, poor, bad), substrate type, topography, and tree density. A multiple logistic regression model identified nest substrate type, distance to nest, and observer experience level as significant predictors of detection rates (P < 0.05). The overall model was significant (??26 = 124.4, P < 0.001, n = 255 nest observations), and the correct classification rate was 78.4%. During 2 validation surveys, observers saw 23.7% (14/59) and 36.5% (23/63) of the actual population. Sightability model predictions, with 90% confidence intervals, captured the true population in both tests. Our results indicate standardized aerial surveys, when used in conjunction with the predictive sightability model, can provide unbiased population estimates for nesting ferruginous hawks.

Climate change projections over three metropolitan regions in Southeast Brazil using the non-hydrostatic Eta regional climate model at 5-km resolution

NASA Astrophysics Data System (ADS)

Lyra, Andre; Tavares, Priscila; Chou, Sin Chan; Sueiro, Gustavo; Dereczynski, Claudine; Sondermann, Marcely; Silva, Adan; Marengo, José; Giarolla, Angélica

2018-04-01

The objective of this work is to assess changes in three metropolitan regions of Southeast Brazil (Rio de Janeiro, São Paulo, and Santos) based on the projections produced by the Eta Regional Climate Model (RCM) at very high spatial resolution, 5 km. The region, which is densely populated and extremely active economically, is frequently affected by intense rainfall events that trigger floods and landslides during the austral summer. The analyses are carried out for the period between 1961 and 2100. The 5-km simulations are results from a second downscaling nesting in the HadGEM2-ES RCP4.5 and RCP8.5 simulations. Prior to the assessment of the projections, the higher resolution simulations were evaluated for the historical period (1961-1990). The comparison between the 5-km and the coarser driver model simulations shows that the spatial patterns of precipitation and temperature of the 5-km Eta simulations are in good agreement with the observations. The simulated frequency distribution of the precipitation and temperature extremes from the 5-km Eta RCM is consistent with the observed structure and extreme values. Projections of future climate change using the 5-km Eta runs show stronger warming in the region, primarily during the summer season, while precipitation is strongly reduced. Projected temperature extremes show widespread heating with maximum temperatures increasing by approximately 9 °C in the three metropolitan regions by the end of the century in the RCP8.5 scenario. A trend of drier climate is also projected using indices based on daily precipitation, which reaches annual rainfall reductions of more than 50 % in the state of Rio de Janeiro and between 40 and 45 % in São Paulo and Santos. The magnitude of these changes has negative implications to the population health conditions, energy security, and economy.

Prediction of cancer incidence and mortality in Korea, 2014.

PubMed

Jung, Kyu-Won; Won, Young-Joo; Kong, Hyun-Joo; Oh, Chang-Mo; Lee, Duk Hyoung; Lee, Jin Soo

2014-04-01

We studied and reported on cancer incidence and mortality rates as projected for the year 2014 in order to estimate Korea's current cancer burden. Cancer incidence data from 1999 to 2011 were obtained from the Korea National Cancer Incidence Database, and cancer mortality data from 1993 to 2012 were acquired from Statistics Korea. Cancer incidence in 2014 was projected by fitting a linear regression model to observed age-specific cancer incidence rates against observed years, then multiplying the projected age-specific rates by the age-specific population. For cancer mortality, a similar procedure was employed, except that a Joinpoint regression model was used to determine at which year the linear trend changed significantly. A total of 265,813 new cancer cases and 74,981 cancer deaths are expected to occur in Korea in 2014. Further, the crude incidence rate per 100,000 of all sites combined will likely reach 524.7 and the age-standardized incidence rate, 338.5. Meanwhile, the crude mortality rate of all sites combined and age-standardized rate are projected to be 148.0 and 84.6, respectively. Given the rapid rise in prostate cancer cases, it is anticipated to be the fourth most frequently occurring cancer site in men for the first time. Cancer has become the most prominent public health concern in Korea, and as the population ages, the nation's cancer burden will continue to increase.

Mapping Application for Penguin Populations and Projected Dynamics (MAPPPD): Data and Tools for Dynamic Management and Decision Support

NASA Technical Reports Server (NTRS)

Humphries, G. R. W.; Naveen, R.; Schwaller, M.; Che-Castaldo, C.; McDowall, P.; Schrimpf, M.; Schrimpf, Michael; Lynch, H. J.

2017-01-01

The Mapping Application for Penguin Populations and Projected Dynamics (MAPPPD) is a web-based, open access, decision-support tool designed to assist scientists, non-governmental organizations and policy-makers working to meet the management objectives as set forth by the Commission for the Conservation of Antarctic Marine Living Resources (CCAMLR) and other components of the Antarctic Treaty System (ATS) (that is, Consultative Meetings and the ATS Committee on Environmental Protection). MAPPPD was designed specifically to complement existing efforts such as the CCAMLR Ecosystem Monitoring Program (CEMP) and the ATS site guidelines for visitors. The database underlying MAPPPD includes all publicly available (published and unpublished) count data on emperor, gentoo, Adelie) and chinstrap penguins in Antarctica. Penguin population models are used to assimilate available data into estimates of abundance for each site and year.Results are easily aggregated across multiple sites to obtain abundance estimates over any user-defined area of interest. A front end web interface located at www.penguinmap.com provides free and ready access to the most recent count and modelled data, and can act as a facilitator for data transfer between scientists and Antarctic stakeholders to help inform management decisions for the continent.

Implementation of a deidentified federated data network for population-based cohort discovery

PubMed Central

Abend, Aaron; Mandel, Aaron; Geraghty, Estella; Gabriel, Davera; Wynden, Rob; Kamerick, Michael; Anderson, Kent; Rainwater, Julie; Tarczy-Hornoch, Peter

2011-01-01

Objective The Cross-Institutional Clinical Translational Research project explored a federated query tool and looked at how this tool can facilitate clinical trial cohort discovery by managing access to aggregate patient data located within unaffiliated academic medical centers. Methods The project adapted software from the Informatics for Integrating Biology and the Bedside (i2b2) program to connect three Clinical Translational Research Award sites: University of Washington, Seattle, University of California, Davis, and University of California, San Francisco. The project developed an iterative spiral software development model to support the implementation and coordination of this multisite data resource. Results By standardizing technical infrastructures, policies, and semantics, the project enabled federated querying of deidentified clinical datasets stored in separate institutional environments and identified barriers to engaging users for measuring utility. Discussion The authors discuss the iterative development and evaluation phases of the project and highlight the challenges identified and the lessons learned. Conclusion The common system architecture and translational processes provide high-level (aggregate) deidentified access to a large patient population (>5 million patients), and represent a novel and extensible resource. Enhancing the network for more focused disease areas will require research-driven partnerships represented across all partner sites. PMID:21873473

Implementation of a deidentified federated data network for population-based cohort discovery.

PubMed

Anderson, Nicholas; Abend, Aaron; Mandel, Aaron; Geraghty, Estella; Gabriel, Davera; Wynden, Rob; Kamerick, Michael; Anderson, Kent; Rainwater, Julie; Tarczy-Hornoch, Peter

2012-06-01

The Cross-Institutional Clinical Translational Research project explored a federated query tool and looked at how this tool can facilitate clinical trial cohort discovery by managing access to aggregate patient data located within unaffiliated academic medical centers. The project adapted software from the Informatics for Integrating Biology and the Bedside (i2b2) program to connect three Clinical Translational Research Award sites: University of Washington, Seattle, University of California, Davis, and University of California, San Francisco. The project developed an iterative spiral software development model to support the implementation and coordination of this multisite data resource. By standardizing technical infrastructures, policies, and semantics, the project enabled federated querying of deidentified clinical datasets stored in separate institutional environments and identified barriers to engaging users for measuring utility. The authors discuss the iterative development and evaluation phases of the project and highlight the challenges identified and the lessons learned. The common system architecture and translational processes provide high-level (aggregate) deidentified access to a large patient population (>5 million patients), and represent a novel and extensible resource. Enhancing the network for more focused disease areas will require research-driven partnerships represented across all partner sites.

Rapid processing of chemosensor transients in a neuromorphic implementation of the insect macroglomerular complex

PubMed Central

Pearce, Timothy C.; Karout, Salah; Rácz, Zoltán; Capurro, Alberto; Gardner, Julian W.; Cole, Marina

2012-01-01

We present a biologically-constrained neuromorphic spiking model of the insect antennal lobe macroglomerular complex that encodes concentration ratios of chemical components existing within a blend, implemented using a set of programmable logic neuronal modeling cores. Depending upon the level of inhibition and symmetry in its inhibitory connections, the model exhibits two dynamical regimes: fixed point attractor (winner-takes-all type), and limit cycle attractor (winnerless competition type) dynamics. We show that, when driven by chemosensor input in real-time, the dynamical trajectories of the model's projection neuron population activity accurately encode the concentration ratios of binary odor mixtures in both dynamical regimes. By deploying spike timing-dependent plasticity in a subset of the synapses in the model, we demonstrate that a Hebbian-like associative learning rule is able to organize weights into a stable configuration after exposure to a randomized training set comprising a variety of input ratios. Examining the resulting local interneuron weights in the model shows that each inhibitory neuron competes to represent possible ratios across the population, forming a ratiometric representation via mutual inhibition. After training the resulting dynamical trajectories of the projection neuron population activity show amplification and better separation in their response to inputs of different ratios. Finally, we demonstrate that by using limit cycle attractor dynamics, it is possible to recover and classify blend ratio information from the early transient phases of chemosensor responses in real-time more rapidly and accurately compared to a nearest-neighbor classifier applied to the normalized chemosensor data. Our results demonstrate the potential of biologically-constrained neuromorphic spiking models in achieving rapid and efficient classification of early phase chemosensor array transients with execution times well beyond biological timescales. PMID:23874265

Quantifying Land and People Exposed to Sea-Level Rise with No Mitigation and 1.5°C and 2.0°C Rise in Global Temperatures to Year 2300

NASA Astrophysics Data System (ADS)

Brown, S.; Nicholls, R. J.; Goodwin, P.; Haigh, I. D.; Lincke, D.; Vafeidis, A. T.; Hinkel, J.

2018-03-01

We use multiple synthetic mitigation sea-level scenarios, together with a non-mitigation sea-level scenario from the Warming Acidification and Sea-level Projector model. We find sea-level rise (SLR) continues to accelerate post-2100 for all but the most aggressive mitigation scenarios indicative of 1.5°C and 2.0°C. Using the Dynamic Interactive Vulnerability Assessment modeling framework, we project land and population exposed in the 1 in 100 year coastal flood plain under SLR and population change. In 2000, the flood plain is estimated at 540 × 103 km2. By 2100, under the mitigation scenarios, it ranges between 610 × 103 and 640 × 103 km2 (580 × 103 and 700 × 103 km2 for the 5th and 95th percentiles). Thus differences between the mitigation scenarios are small in 2100. However, in 2300, flood plains are projected to increase to between 700 × 103 and 960 × 103 km2 in 2300 (610 × 103 and 1290 × 103 km2) for the mitigation scenarios, but 1630 × 103 km2 (1190 × 103 and 2220 × 103 km2) for the non-mitigation scenario. The proportion of global population exposed to SLR in 2300 is projected to be between 1.5% and 5.4% (1.2%-7.6%) (assuming no population growth after 2100) for the aggressive mitigation and the non-mitigation scenario, respectively. Hence over centennial timescales there are significant benefits to climate change mitigation and temperature stabilization. However, sea-levels will continue to rise albeit at lower rates. Thus potential impacts will keep increasing necessitating adaptation to existing coastal infrastructure and the careful planning of new coastal developments.

Impact of the population at risk of diabetes on projections of diabetes burden in the United States: an epidemic on the way

PubMed Central

Baker, R.; Koopman, R. J.; Saxena, S.; Diaz, V. A.; Everett, C. J.; Majeed, A.

2006-01-01

Aims/hypothesis The aim of this study was to make projections of the future diabetes burden for the adult US population based in part on the prevalence of individuals at high risk of developing diabetes. Materials and methods Models were created from data in the nationally representative National Health and Nutrition Examination Survey (NHANES) II mortality survey (1976–1992), the NHANES III (1988–1994) and the NHANES 1999–2002. Population models for adults (>20 years of age) from NHANES III data were fitted to known diabetes prevalence in the NHANES 1999–2002 before making future projections. We used a multivariable diabetes risk score to estimate the likelihood of diabetes incidence in 10 years. Estimates of future diabetes (diagnosed and undiagnosed) prevalence in 2011, 2021, and 2031 were made under several assumptions. Results Based on the multivariable diabetes risk score, the number of adults at high risk of diabetes was 38.4 million in 1991 and 49.9 million in 2001. The total diabetes burden is anticipated to be 11.5% (25.4 million) in 2011, 13.5% (32.6 million) in 2021, and 14.5% (37.7 million) in 2031. Among individuals aged 30 to 39 years old who are not currently targeted for screening according to age, the prevalence of diabetes is expected to rise from 3.7% in 2001 to 5.2% in 2031. By 2031, 20.2% of adult Hispanic individuals are expected to have diabetes. Conclusions/interpretation The prevalence of diabetes is projected to rise to substantially greater levels than previously estimated. Diabetes prevalence within the Hispanic community is projected to be potentially overwhelming. Electronic supplementary material Supplementary material is available in the online version of this article at http://dx.doi.org/10.1007/s00125-006-0528-5 and is accessible to authorized users. PMID:17119914

Projecting the Global Distribution of the Emerging Amphibian Fungal Pathogen, Batrachochytrium dendrobatidis, Based on IPCC Climate Futures.

PubMed

Xie, Gisselle Yang; Olson, Deanna H; Blaustein, Andrew R

2016-01-01

Projected changes in climate conditions are emerging as significant risk factors to numerous species, affecting habitat conditions and community interactions. Projections suggest species range shifts in response to climate change modifying environmental suitability and is supported by observational evidence. Both pathogens and their hosts can shift ranges with climate change. We consider how climate change may influence the distribution of the emerging infectious amphibian chytrid fungus, Batrachochytrium dendrobatidis (Bd), a pathogen associated with worldwide amphibian population losses. Using an expanded global Bd database and a novel modeling approach, we examined a broad set of climate metrics to model the Bd-climate niche globally and regionally, then project how climate change may influence Bd distributions. Previous research showed that Bd distribution is dependent on climatic variables, in particular temperature. We trained a machine-learning model (random forest) with the most comprehensive global compilation of Bd sampling records (~5,000 site-level records, mid-2014 summary), including 13 climatic variables. We projected future Bd environmental suitability under IPCC scenarios. The learning model was trained with combined worldwide data (non-region specific) and also separately per region (region-specific). One goal of our study was to estimate of how Bd spatial risks may change under climate change based on the best available data. Our models supported differences in Bd-climate relationships among geographic regions. We projected that Bd ranges will shift into higher latitudes and altitudes due to increased environmental suitability in those regions under predicted climate change. Specifically, our model showed a broad expansion of areas environmentally suitable for establishment of Bd on amphibian hosts in the temperate zones of the Northern Hemisphere. Our projections are useful for the development of monitoring designs in these areas, especially for sensitive species and those vulnerable to multiple threats.

A model of northern pintail productivity and population growth rate

USGS Publications Warehouse

Flint, Paul L.; Grand, James B.; Rockwell, Robert F.

1998-01-01

Our objective was to synthesize individual components of reproductive ecology into a single estimate of productivity and to assess the relative effects of survival and productivity on population dynamics. We used information on nesting ecology, renesting potential, and duckling survival of northern pintails (Anas acuta) collected on the Yukon-Kuskokwim Delta (Y-K Delta), Alaska, 1991-95, to model the number of ducklings produced under a range of nest success and duckling survival probabilities. Using average values of 25% nest success, 11% duckling survival, and 56% renesting probability from our study population, we calculated that all young in our population were produced by 13% of the breeding females, and that early-nesting females produced more young than later-nesting females. Further, we calculated, on average, that each female produced only 0.16 young females/nesting season. We combined these results with estimates of first-year and adult survival to examine the growth rate (X) of the population and the relative contributions of these demographic parameters to that growth rate. Contrary to aerial survey data, the population projection model suggests our study population is declining rapidly (X = 0.6969). The relative effects on population growth rate were 0.1175 for reproductive success, 0.1175 for first-year survival, and 0.8825 for adult survival. Adult survival had the greatest influence on X for our population, and this conclusion was robust over a range of survival and productivity estimates. Given published estimates of annual survival for adult females (61%), our model suggested nest success and duckling survival need to increase to approximately 40% to achieve population stability. We discuss reasons for the apparent discrepancy in population trends between our model and aerial surveys in terms of bias in productivity and survival estimates.

The projected health care burden of Type 2 diabetes in the UK from 2000 to 2060.

PubMed

Bagust, A; Hopkinson, P K; Maslove, L; Currie, C J

2002-07-01

To predict the incidence and prevalence of Type 2 diabetes in the UK, the trends in the levels of diabetes-related complications, and the associated health care costs for the period 2000-60. An established epidemiological and economic model of the long-term complications and health care costs of Type 2 diabetes was applied to UK population projections from 2000 to 2060. The model was used to calculate the incidence and prevalence of Type 2 diabetes, the caseloads and population burden for diabetes-related complications, and annual NHS health care costs for Type 2 diabetes over this time period. The total UK population will not increase by more than 3% at any time in the next 60 years. However, the population over 30 will increase by a maximum of 11% by 2030. Due to population ageing, in 2036 there will be approximately 20% more cases of Type 2 diabetes than in 2000. Cases of diabetes-related complications will increase rapidly to peak 20-30% above present levels between 2035 and 2045, before showing a modest decline. The cost of health care for patients with Type 2 diabetes rises by up to 25% during this period, but because of reductions in the economically active age groups, the relative economic burden of the disease can be expected to increase by 40-50%. In the next 30 years Type 2 diabetes will present a serious clinical and financial challenge to the UK NHS.

The potential effects of climate change on malaria in tropical Africa using regionalised climate projections

NASA Astrophysics Data System (ADS)

Ermert, V.; Fink, A. H.; Paeth, H.; Morse, A. P.

2012-04-01

The projected climate change will probably alter the range and transmission potential of malaria in Africa. The potential impacts of climate change on the malaria distribution is assessed for tropical Africa. Bias-corrected regional climate projections with a horizontal resolution of 0.5° are used from the Regional Model (REMO), which include land use and land cover changes. The malaria models employed are the 2010 version of the Liverpool Malaria Model (LMM2010), the Garki model, the Plasmodium falciparum infection model from Smith et al. (2005) (S2005), and the Malaria Seasonality Model (MSM) from the Mapping Malaria Risk in Africa project. The results of the models are compared with data from the Malaria Atlas Project (MAP) and novel validation procedures for the LMM2010 and MSM lend more credence to their results. For climate scenarios A1B and B1 and for 2001-2050, REMO projects an overall drying and warming trend in the African malaria belt, that is largely imposed by the man-made degradation of vegetation. As a result, the malaria projections show a decreased malaria spread in West Africa. The northern Sahel is no more suitable for malaria in the projections. More unstable malaria transmission and shorter malaria seasons are expected for various areas farther south. An increase in the malaria epidemic risk is found for more densely populated areas in the southern part of the Sahel. In East Africa, higher temperatures and nearly unchanged precipitation patterns lead to longer transmission seasons and an increase in the area of highland malaria. For altitudes up to 2000 m the malaria transmission stabilises and the epidemic risk is reduced but for higher altitudes the risk of malaria epidemics is increased. The results of the more complex and simple malaria models are similar to each other. However, a different response to the warming of highlands is found for the LMM2010 and MSM. This shows the requirement of a multi model uncertainty analysis for the projection of the future malaria spread.

Modeling Urban Energy Savings Scenarios Using Earth System Microclimate and Urban Morphology

NASA Astrophysics Data System (ADS)

Allen, M. R.; Rose, A.; New, J. R.; Yuan, J.; Omitaomu, O.; Sylvester, L.; Branstetter, M. L.; Carvalhaes, T. M.; Seals, M.; Berres, A.

2017-12-01

We analyze and quantify the relationships among climatic conditions, urban morphology, population, land cover, and energy use so that these relationships can be used to inform energy-efficient urban development and planning. We integrate different approaches across three research areas: earth system modeling; impacts, adaptation and vulnerability; and urban planning in order to address three major gaps in the existing capability in these areas: i) neighborhood resolution modeling and simulation of urban micrometeorological processes and their effect on and from regional climate; ii) projections for future energy use under urbanization and climate change scenarios identifying best strategies for urban morphological development and energy savings; iii) analysis and visualization tools to help planners optimally use these projections.

Promoting excellence in end-of-life care: a report on innovative models of palliative care.

PubMed

Byock, Ira; Twohig, Jeanne Sheils; Merriman, Melanie; Collins, Karyn

2006-02-01

Promoting Excellence in End-of Life Care, a national program of The Robert Wood Johnson Foundation, funded 22 demonstration projects representing a wide range of health care settings and patient populations to develop innovative models for delivering palliative care that addressed documented deficiencies in the care of patients and families facing the final stage of life. To determine the practicality (feasibility of development and operation as well as acceptance by stakeholders) of new models of care and to determine the impact of the models on access to, quality of and financing for palliative care. The program cannot report scientifically rigorous outcomes, but the grant-funded projects used a variety of methods and measures to assess acceptance of new models and their impact from the perspectives of various stakeholders, including patients and their families, clinicians, administrators and payers. While it is not possible to aggregate data across projects, the data reported to the Promoting Excellence national program office were used to describe program impact with respect to the practicality of palliative care service integration into existing clinical care settings (feasibility and acceptance by stakeholders), the availability and use of palliative care services (access), quality of care (conformance to patient expectations and accepted clinical standards) and costs of care. The 22 projects provided services in urban as well as rural settings, in integrated health systems, hospitals, outpatient clinics, cancer centers, nursing homes, renal dialysis clinics, inner city public health and safety net systems and prisons. Populations served included prison inmates, military veterans, renal dialysis patients, Native Americans, Native Alaskans, and African American patients, inner-city medically underserved patients, pediatric patients, and persons with serious mental illness patients. Hosting or adopting institutions sustained or expanded twenty of the 22 models, and feedback from all stakeholders was positive. Project sites developed and utilized new palliative care services and addressed quality through implementation of new standards and clinical protocols. Costs of care, where they could be assessed, were unaffected or decreased for project patients versus historical or concurrent controls. The 22 Promoting Excellence in End-of Life Care projects demonstrated that by individualizing patient and family assessment, effectively employing existing resources and aligning services with specific patient and family needs, it is possible to expand access to palliative services and improve quality of care in ways that are financially feasible and acceptable to patients, families, clinicians, administrators, and payers.

Projecting surgeon supply using a dynamic model.

PubMed

Fraher, Erin P; Knapton, Andy; Sheldon, George F; Meyer, Anthony; Ricketts, Thomas C

2013-05-01

To develop a projection model to forecast the head count and full-time equivalent supply of surgeons by age, sex, and specialty in the United States from 2009 to 2028. The search for the optimal number and specialty mix of surgeons to care for the United States population has taken on increased urgency under health care reform. Expanded insurance coverage and an aging population will increase demand for surgical and other medical services. Accurate forecasts of surgical service capacity are crucial to inform the federal government, training institutions, professional associations, and others charged with improving access to health care. The study uses a dynamic stock and flow model that simulates future changes in numbers and specialty type by factoring in changes in surgeon demographics and policy factors. : Forecasts show that overall surgeon supply will decrease 18% during the period form 2009 to 2028 with declines in all specialties except colorectal, pediatric, neurological surgery, and vascular surgery. Model simulations suggest that none of the proposed changes to increase graduate medical education currently under consideration will be sufficient to offset declines. The length of time it takes to train surgeons, the anticipated decrease in hours worked by surgeons in younger generations, and the potential decreases in graduate medical education funding suggest that there may be an insufficient surgeon workforce to meet population needs. Existing maldistribution patterns are likely to be exacerbated, leading to delayed or lost access to time-sensitive surgical procedures, particularly in rural areas.

Modeled response of the West Nile virus vector Culex quinquefasciatus to changing climate using the dynamic mosquito simulation model

NASA Astrophysics Data System (ADS)

Morin, Cory W.; Comrie, Andrew C.

2010-09-01

Climate can strongly influence the population dynamics of disease vectors and is consequently a key component of disease ecology. Future climate change and variability may alter the location and seasonality of many disease vectors, possibly increasing the risk of disease transmission to humans. The mosquito species Culex quinquefasciatus is a concern across the southern United States because of its role as a West Nile virus vector and its affinity for urban environments. Using established relationships between atmospheric variables (temperature and precipitation) and mosquito development, we have created the Dynamic Mosquito Simulation Model (DyMSiM) to simulate Cx. quinquefasciatus population dynamics. The model is driven with climate data and validated against mosquito count data from Pasco County, Florida and Coachella Valley, California. Using 1-week and 2-week filters, mosquito trap data are reproduced well by the model ( P < 0.0001). Dry environments in southern California produce different mosquito population trends than moist locations in Florida. Florida and California mosquito populations are generally temperature-limited in winter. In California, locations are water-limited through much of the year. Using future climate projection data generated by the National Center for Atmospheric Research CCSM3 general circulation model, we applied temperature and precipitation offsets to the climate data at each location to evaluate mosquito population sensitivity to possible future climate conditions. We found that temperature and precipitation shifts act interdependently to cause remarkable changes in modeled mosquito population dynamics. Impacts include a summer population decline from drying in California due to loss of immature mosquito habitats, and in Florida a decrease in late-season mosquito populations due to drier late summer conditions.

Nurse practitioners in aged care: documentary analysis of successful project proposals.

PubMed

Clark, Shannon J; Parker, Rhian M; Davey, Rachel

2014-11-01

Meeting the primary health care needs of an aging population is an increasing challenge for many Western nations. In Australia, the federal government introduced a program to develop, test, and evaluate nurse practitioner models in aged care settings. In this article, we present a documentary analysis of 32 project proposals awarded funding under the Nurse Practitioner-Aged Care Models of Practice Program. Successfully funded models were diverse and were operated by a range of organizations across Australia. We identified three key priorities as underlying the proposed models: "The right care," "in the right place," and "at the right time." In this article, we explore how these priorities were presented by different applicants in different ways. Through the presentation of their models, the program's applicants identified and proposed to address current gaps in health services. Applicants contrasted their proposed models with available services to create persuasive and competitive applications for funding. © The Author(s) 2014.

Postdispersal seed predation limits the abundance of a long-lived perennial forb (Lithospermum ruderale).

PubMed

Bricker, Mary; Maron, John

2012-03-01

Loss of seeds to consumers is common in plant communities, but the degree to which these losses influence plant abundance or population growth is often unclear. This is particularly the case for postdispersal seed predation by rodents, as most studies of rodent seed predation have focused on the sources of spatiotemporal variation in seed loss but not quantified the population consequences of this loss. In previous work we showed that seed predation by deer mice (Peromyscus maniculatus) substantially reduced seedling recruitment and establishment of Lithospermum ruderale (Boraginaceae), a long-lived perennial forb. To shed light on how rodent seed predation and the near-term effects on plant recruitment might influence longer-term patterns of L. ruderale population growth, we combined experimental results with demographic data in stage-based population models. Model outputs revealed that rodent seed predation had a significant impact on L. ruderale population growth rate (lambda). With the removal of postdispersal seed predation, the projected population growth rates increased between 0.06 and 0.12, depending on site (mean deltalambda across sites = 0.08). Seed predation shifted the projected stable stage distribution of populations from one with a high proportion of young plants to one in which larger adult size classes dominate. Elasticities of vital rates also changed, with germination and growth of seedlings and young plants becoming more important with the removal of seed predation. Simulations varying the magnitude of seed predation pressure while holding other vital rates constant showed that seed predation could lower lambda even if only 40% of available seeds were consumed. These results demonstrate that rodent granivory can be a potent force limiting the abundance of a long-lived perennial forb.

Tidal saltmarsh fragmentation and persistence of San Pablo Song Sparrows (Melospiza melodia samuelis): Assessing benefits of wetland restoration in San Francisco Bay

USGS Publications Warehouse

Takekawa, John Y.; Sacks, B.N.; Woo, I.; Johnson, M.L.; Wylie, G.D.; ,

2006-01-01

The San Pablo Song Sparrow (Melospiza melodia samuelis) is one of three morphologically distinct Song Sparrow subspecies in tidal marshes of the San Francisco Bay estuary. These subspecies are rare, because as the human population has grown, diking and development have resulted in loss of 79% of the historic tidal marshes. Hundreds of projects have been proposed in the past decade to restore tidal marshes and benefit endemic populations. To evaluate the value of these restoration projects for Song Sparrows, we developed a population viability analysis (PVA) model to examine persistence of samuelis subspecies in relation to parcel size, connectivity, and catastrophe in San Pablo Bay. A total of 101 wetland parcels were identified from coverages of modern and historic tidal marshes. Parcels were grouped into eight fragments in the historical landscape and 10 in the present landscape. Fragments were defined as a group of parcels separated by >1 km, a distance that precluded regular interchange. Simulations indicated that the historic (circa 1850) samuelis population was three times larger than the modern population. However, only very high levels (>70% mortality) of catastrophe would threaten their persistence. Persistence of populations was sensitive to parcel size at a carrying capacity of <10 pairs, but connectivity of parcels was found to have little importance because habitats were dominated by a few large parcels. Our analysis indicates little risk of extinction of the samuelis subspecies with the current extent of tidal marshes, but the vulnerability of the small-est parcels suggests that restoration should create larger continuous tracts. Thus, PVA models may be useful tools for balancing the costs and benefits of restoring habitats for threatened tidal-marsh populations in wetland restoration planning.

ADVANCEMENTS IN SOURCE-TO-DOSE ANALYSIS OF POPULATION EXPOSURES TO OZONE

EPA Science Inventory

The current study takes advantage of the observations from regional air quality monitoring networks, the data from the NE-OPS (North East Oxidant and Particulate Study) Project in the Philadelphia region, and regional photochemical air quality model predictions to obtain and co...

Changes in Extreme Maximum Temperature Events and Population Exposure in China under Global Warming Scenarios of 1.5 and 2.0°C: Analysis Using the Regional Climate Model COSMO-CLM

NASA Astrophysics Data System (ADS)

Zhan, Mingjin; Li, Xiucang; Sun, Hemin; Zhai, Jianqing; Jiang, Tong; Wang, Yanjun

2018-02-01

We used daily maximum temperature data (1986-2100) from the COSMO-CLM (COnsortium for Small-scale MOdeling in CLimate Mode) regional climate model and the population statistics for China in 2010 to determine the frequency, intensity, coverage, and population exposure of extreme maximum temperature events (EMTEs) with the intensity-area-duration method. Between 1986 and 2005 (reference period), the frequency, intensity, and coverage of EMTEs are 1330-1680 times yr-1, 31.4-33.3°C, and 1.76-3.88 million km2, respectively. The center of the most severe EMTEs is located in central China and 179.5-392.8 million people are exposed to EMTEs annually. Relative to 1986-2005, the frequency, intensity, and coverage of EMTEs increase by 1.13-6.84, 0.32-1.50, and 15.98%-30.68%, respectively, under 1.5°C warming; under 2.0°C warming, the increases are 1.73-12.48, 0.64-2.76, and 31.96%-50.00%, respectively. It is possible that both the intensity and coverage of future EMTEs could exceed the most severe EMTEs currently observed. Two new centers of EMTEs are projected to develop under 1.5°C warming, one in North China and the other in Southwest China. Under 2.0°C warming, a fourth EMTE center is projected to develop in Northwest China. Under 1.5 and 2.0°C warming, population exposure is projected to increase by 23.2%-39.2% and 26.6%-48%, respectively. From a regional perspective, population exposure is expected to increase most rapidly in Southwest China. A greater proportion of the population in North, Northeast, and Northwest China will be exposed to EMTEs under 2.0°C warming. The results show that a warming world will lead to increases in the intensity, frequency, and coverage of EMTEs. Warming of 2.0°C will lead to both more severe EMTEs and the exposure of more people to EMTEs. Given the probability of the increased occurrence of more severe EMTEs than in the past, it is vitally important to China that the global temperature increase is limited within 1.5°C.

LEGEND, a LEO-to-GEO Environment Debris Model

NASA Technical Reports Server (NTRS)

Liou, Jer Chyi; Hall, Doyle T.

2013-01-01

LEGEND (LEO-to-GEO Environment Debris model) is a three-dimensional orbital debris evolutionary model that is capable of simulating the historical and future debris populations in the near-Earth environment. The historical component in LEGEND adopts a deterministic approach to mimic the known historical populations. Launched rocket bodies, spacecraft, and mission-related debris (rings, bolts, etc.) are added to the simulated environment. Known historical breakup events are reproduced, and fragments down to 1 mm in size are created. The LEGEND future projection component adopts a Monte Carlo approach and uses an innovative pair-wise collision probability evaluation algorithm to simulate the future breakups and the growth of the debris populations. This algorithm is based on a new "random sampling in time" approach that preserves characteristics of the traditional approach and captures the rapidly changing nature of the orbital debris environment. LEGEND is a Fortran 90-based numerical simulation program. It operates in a UNIX/Linux environment.

Modeling the Economic Feasibility of Large-Scale Net-Zero Water Management: A Case Study.

PubMed

Guo, Tianjiao; Englehardt, James D; Fallon, Howard J

  While municipal direct potable water reuse (DPR) has been recommended for consideration by the U.S. National Research Council, it is unclear how to size new closed-loop DPR plants, termed "net-zero water (NZW) plants", to minimize cost and energy demand assuming upgradient water distribution. Based on a recent model optimizing the economics of plant scale for generalized conditions, the authors evaluated the feasibility and optimal scale of NZW plants for treatment capacity expansion in Miami-Dade County, Florida. Local data on population distribution and topography were input to compare projected costs for NZW vs the current plan. Total cost was minimized at a scale of 49 NZW plants for the service population of 671,823. Total unit cost for NZW systems, which mineralize chemical oxygen demand to below normal detection limits, is projected at ~$10.83 / 1000 gal, approximately 13% above the current plan and less than rates reported for several significant U.S. cities.

The BMC ACCESS project: the development of a medically enhanced safe haven shelter.

PubMed

Lincoln, Alisa; Johnson, Peggy; Espejo, Dennis; Plachta-Elliott, Sara; Lester, Peggy; Shanahan, Christopher; Abbott, Susan; Cabral, Howard; Jamanka, Amber; Delman, Jonathan; Kenny, Patty

2009-10-01

This paper describes the development and implementation of the Boston Medical Center (BMC) Advanced Clinical Capacity for Engagement, Safety, and Services Project. In October 2002, the BMC Division of Psychiatry became the first such entity to open a Safe Haven shelter for people who are chronically homeless, struggling with severe mental illness, and actively substance abusing. The low-demand Safe Haven model targets the most difficult to reach population and serves as a "portal of entry" to the mental health and addiction service systems. In this paper, the process by which this blended funded, multi-level collaboration, consisting of a medical center, state, city, local, and community-based consumer organizations, was created and is maintained, as well as the clinical model of care is described. Lessons learned from creating the Safe Haven Shelter and the development and implementation of the consumer-informed evaluation are discussed as well as implications for future work with this population.

Climate and human intervention effects on future fire activity and consequences for air pollution across the 21st century

NASA Astrophysics Data System (ADS)

Val Martin, M.; Pierce, J. R.; Heald, C. L.; Li, F.; Lawrence, D. M.; Wiedinmyer, C.; Tilmes, S.; Vitt, F.

2016-12-01

Emissions of aerosols and gases from fires have been shown to adversely affect air quality across the world. Fire activity is strongly related to climate and anthropogenic activities. Current fire projections for the 21st century seem very uncertain, ranging from increasing to declining depending on the climate, land cover change and population growth scenarios used. Here we present an analysis of the changes in future wildfire activity and consequences on air quality, with focus on PM2.5 and surface O3 over regions vulnerable to fire. We use the global Community Earth System Model (CESM) with a process-based fire model to simulate emissions from agriculture, peatland, deforestation and landscape fires for present-day and throughout the current century. We consider two future Representative Concentration Pathways climate scenarios combined with population density changes predicted from Shared Socio-economic Pathways to project climate and demographic effects on fire activity and further consequences for future air quality.

Modeling the Potential Effects of New Tobacco Products and Policies. A Dynamic Population Model for Multiple Product Use and Harm

DOE PAGES

Vugrin, Eric D.; Rostron, Brian L.; Verzi, Stephen J.; ...

2015-03-27

Background Recent declines in US cigarette smoking prevalence have coincided with increases in use of other tobacco products. Multiple product tobacco models can help assess the population health impacts associated with use of a wide range of tobacco products. Methods and Findings We present a multi-state, dynamical systems population structure model that can be used to assess the effects of tobacco product use behaviors on population health. The model incorporates transition behaviors, such as initiation, cessation, switching, and dual use, related to the use of multiple products. The model tracks product use prevalence and mortality attributable to tobacco use formore » the overall population and by sex and age group. The model can also be used to estimate differences in these outcomes between scenarios by varying input parameter values. We demonstrate model capabilities by projecting future cigarette smoking prevalence and smoking-attributable mortality and then simulating the effects of introduction of a hypothetical new lower-risk tobacco product under a variety of assumptions about product use. Sensitivity analyses were conducted to examine the range of population impacts that could occur due to differences in input values for product use and risk. We demonstrate that potential benefits from cigarette smokers switching to the lower-risk product can be offset over time through increased initiation of this product. Model results show that population health benefits are particularly sensitive to product risks and initiation, switching, and dual use behaviors. Conclusion Our model incorporates the variety of tobacco use behaviors and risks that occur with multiple products. As such, it can evaluate the population health impacts associated with the introduction of new tobacco products or policies that may result in product switching or dual use. Further model development will include refinement of data inputs for non-cigarette tobacco products and inclusion of health outcomes such as morbidity and disability.« less

Modeling the Potential Effects of New Tobacco Products and Policies: A Dynamic Population Model for Multiple Product Use and Harm

PubMed Central

Vugrin, Eric D.; Rostron, Brian L.; Verzi, Stephen J.; Brodsky, Nancy S.; Brown, Theresa J.; Choiniere, Conrad J.; Coleman, Blair N.; Paredes, Antonio; Apelberg, Benjamin J.

2015-01-01

Background Recent declines in US cigarette smoking prevalence have coincided with increases in use of other tobacco products. Multiple product tobacco models can help assess the population health impacts associated with use of a wide range of tobacco products. Methods and Findings We present a multi-state, dynamical systems population structure model that can be used to assess the effects of tobacco product use behaviors on population health. The model incorporates transition behaviors, such as initiation, cessation, switching, and dual use, related to the use of multiple products. The model tracks product use prevalence and mortality attributable to tobacco use for the overall population and by sex and age group. The model can also be used to estimate differences in these outcomes between scenarios by varying input parameter values. We demonstrate model capabilities by projecting future cigarette smoking prevalence and smoking-attributable mortality and then simulating the effects of introduction of a hypothetical new lower-risk tobacco product under a variety of assumptions about product use. Sensitivity analyses were conducted to examine the range of population impacts that could occur due to differences in input values for product use and risk. We demonstrate that potential benefits from cigarette smokers switching to the lower-risk product can be offset over time through increased initiation of this product. Model results show that population health benefits are particularly sensitive to product risks and initiation, switching, and dual use behaviors. Conclusion Our model incorporates the variety of tobacco use behaviors and risks that occur with multiple products. As such, it can evaluate the population health impacts associated with the introduction of new tobacco products or policies that may result in product switching or dual use. Further model development will include refinement of data inputs for non-cigarette tobacco products and inclusion of health outcomes such as morbidity and disability. PMID:25815840

Modeling the potential effects of new tobacco products and policies: a dynamic population model for multiple product use and harm.

PubMed

Vugrin, Eric D; Rostron, Brian L; Verzi, Stephen J; Brodsky, Nancy S; Brown, Theresa J; Choiniere, Conrad J; Coleman, Blair N; Paredes, Antonio; Apelberg, Benjamin J

2015-01-01

Recent declines in US cigarette smoking prevalence have coincided with increases in use of other tobacco products. Multiple product tobacco models can help assess the population health impacts associated with use of a wide range of tobacco products. We present a multi-state, dynamical systems population structure model that can be used to assess the effects of tobacco product use behaviors on population health. The model incorporates transition behaviors, such as initiation, cessation, switching, and dual use, related to the use of multiple products. The model tracks product use prevalence and mortality attributable to tobacco use for the overall population and by sex and age group. The model can also be used to estimate differences in these outcomes between scenarios by varying input parameter values. We demonstrate model capabilities by projecting future cigarette smoking prevalence and smoking-attributable mortality and then simulating the effects of introduction of a hypothetical new lower-risk tobacco product under a variety of assumptions about product use. Sensitivity analyses were conducted to examine the range of population impacts that could occur due to differences in input values for product use and risk. We demonstrate that potential benefits from cigarette smokers switching to the lower-risk product can be offset over time through increased initiation of this product. Model results show that population health benefits are particularly sensitive to product risks and initiation, switching, and dual use behaviors. Our model incorporates the variety of tobacco use behaviors and risks that occur with multiple products. As such, it can evaluate the population health impacts associated with the introduction of new tobacco products or policies that may result in product switching or dual use. Further model development will include refinement of data inputs for non-cigarette tobacco products and inclusion of health outcomes such as morbidity and disability.

Modeling the Potential Effects of New Tobacco Products and Policies. A Dynamic Population Model for Multiple Product Use and Harm

DOE Office of Scientific and Technical Information (OSTI.GOV)

Vugrin, Eric D.; Rostron, Brian L.; Verzi, Stephen J.

Background Recent declines in US cigarette smoking prevalence have coincided with increases in use of other tobacco products. Multiple product tobacco models can help assess the population health impacts associated with use of a wide range of tobacco products. Methods and Findings We present a multi-state, dynamical systems population structure model that can be used to assess the effects of tobacco product use behaviors on population health. The model incorporates transition behaviors, such as initiation, cessation, switching, and dual use, related to the use of multiple products. The model tracks product use prevalence and mortality attributable to tobacco use formore » the overall population and by sex and age group. The model can also be used to estimate differences in these outcomes between scenarios by varying input parameter values. We demonstrate model capabilities by projecting future cigarette smoking prevalence and smoking-attributable mortality and then simulating the effects of introduction of a hypothetical new lower-risk tobacco product under a variety of assumptions about product use. Sensitivity analyses were conducted to examine the range of population impacts that could occur due to differences in input values for product use and risk. We demonstrate that potential benefits from cigarette smokers switching to the lower-risk product can be offset over time through increased initiation of this product. Model results show that population health benefits are particularly sensitive to product risks and initiation, switching, and dual use behaviors. Conclusion Our model incorporates the variety of tobacco use behaviors and risks that occur with multiple products. As such, it can evaluate the population health impacts associated with the introduction of new tobacco products or policies that may result in product switching or dual use. Further model development will include refinement of data inputs for non-cigarette tobacco products and inclusion of health outcomes such as morbidity and disability.« less

1996-based national population projections for the United Kingdom and constituent countries.

PubMed

Shaw, C

1998-01-01

The 1996-based national population projections, carried out by the Government Actuary in consultation with the Registrars General, show the population of the United Kingdom rising from 58.8 million in 1996 to over 62 million by 2021. The population will become gradually older with the mean age expected to rise from 38.4 years in 1996 to nearly 42 years by 2021. The number of children aged under 16 is projected to fall by 1.0 million (9 per cent) by 2021, while the number aged 65 and over is projected to increase by 2.7 million (29 per cent). Longer-term projections suggest the population will peak around 2031 and then gradually start to fall.

Estimates of future water demand for selected water-service areas in the Upper Duck River basin, central Tennessee; with a section on Methodology used to develop population forecasts for Bedford, Marshall, and Maury counties, Tennessee, from 1993 through 2050

USGS Publications Warehouse

Hutson, S.S.; Schwarz, G.E.

1996-01-01

Estimates of future water demand were determined for selected water-service areas in the upper Duck River basin in central Tennessee through the year 2050. The Duck River is the principal source of publicly-supplied water in the study area providing a total of 15.6 million gallons per day (Mgal/d) in 1993 to the cities of Columbia, Lewisburg, Shelbyville, part of southern Williamson County, and several smaller communities. Municipal water use increased 19 percent from 1980 to 1993 (from 14.5 to 17.2 Mgal/d). Based on certain assumptions about socioeconomic conditions and future development in the basin, water demand should continue to increase through 2050. Projections of municipal water demand for the study area from 1993 to 2015 were made using econometric and single- coefficient (unit-use) requirement models of the per capita type. The models are part of the Institute for Water Resources-Municipal and Industrial Needs System, IWR-MAIN. Socioeconomic data for 1993 were utilized to calibrate the models. Projections of water demand in the study area from 2015 to 2050 were made using a single- coefficient requirement model. A gross per capita use value (unit-requirement) was estimated for each water-service area based on the results generated by IWR-MAIN for year 2015. The gross per capita estimate for 2015 was applied to population projections for year 2050 to calculate water demand. Population was projected using the log-linear form of the Box-Cox regression model. Water demand was simulated for two scenarios. The scenarios were suggested by various planning agencies associated with the study area. The first scenario reflects a steady growth pattern based on present demographic and socioeconomic conditions in the Bedford, Marshall, and Maury/southern Williamson water-service areas. The second scenario considers steady growth in the Bedford and Marshall water-service areas and additional industrial and residential development in the Maury/southern Williamson water-service area beginning in 2000. For the study area, water demand for scenario one shows an increase of 121 percent (from 17.2 to 38 Mgal/d) from 1993 to 2050. In scenario two, simulated water demand increases 150 percent (17.2 to 43 Mgal/d) from 1993 to 2050.

Development and use of role model stories in a community level HIV risk reduction intervention.

PubMed Central

Corby, N H; Enguídanos, S M; Kay, L S

1996-01-01

A theory-based HIV prevention intervention was implemented as part of a five-city AIDS Community Demonstration Project for the development and testing of a community-level intervention to reduce AIDS risk among historically underserved groups. This intervention employed written material containing stories of risk-reducing experiences of members of the priority populations, in this case, injecting drug users, their female sex partners, and female sex workers. These materials were distributed to members of these populations by their peers, volunteers from the population who were trained to deliver social reinforcement for interest in personal risk reduction and the materials. The participation of the priority populations in the development and implementation of the intervention was designed to increase the credibility of the intervention and the acceptance of the message. The techniques involved in developing role-model stories are described in this paper. PMID:8862158

Partnering with insiders: A review of peer models across community-engaged research, education and social care.

PubMed

Vaughn, Lisa M; Whetstone, Crystal; Boards, Alicia; Busch, Melida D; Magnusson, Maria; Määttä, Sylvia

2018-03-07

Within community-engaged research, education and social care, peer models that partner with local "insiders" are increasingly common. Peer models are composed of insider "lay" community members who often share similarities or background with a project's target population. Peers are not academically trained, but work alongside researchers and professionals to carry out specific tasks within a project, or in the truest sense of partnership, peers collaborate throughout the project from start to finish as an equal member of the team. Although peer models are used widely, the literature lacks consistency and clarity. This systematic review of literature used a qualitative thematic synthesis to examine and report how, where and why peer models have been used in research, education and social care. We examined the language and titles used to describe the peers, details of their involvement in community-engaged projects, the setting, content/topic of study, level of engagement and related benefits/outcomes of such models. Focusing on the last 10 years, we conducted a comprehensive literature search twice between September 2016 and June 2017. The search resulted in 814 articles which were assessed for eligibility. Overall, 251 articles met our inclusion criteria and were categorised into three categories: empirical (n = 115); process/descriptive (n = 93); and "about" peers (n = 43). Findings suggest that there is a wide variety of peers, titles and terminology associated with peer models. There is inconsistency in how these models are used and implemented in research studies and projects. The majority of articles used an employment peer model, while only a handful involved peers in all phases of the project. The results of this literature review contribute to understanding the use, development and evolution of peer models. We highlight potential benefits of peer models for peers, their communities and community-engaged work, and we offer recommendations for future implementation of peer models. © 2018 John Wiley & Sons Ltd.

Development of a Community-Based Palliative Care Model for Advance Cancer Patients in Public Health Centers in Busan, Korea.

PubMed

Kim, Sook-Nam; Choi, Soon-Ock; Shin, Seong Hoon; Ryu, Ji-Sun; Baik, Jeong-Won

2017-07-01

A feasible palliative care model for advance cancer patients is needed in Korea with its rapidly aging population and corresponding increase in cancer prevalence. This study describes the process involved in the development of a community-based palliative care (CBPC) model implemented originally in a Busan pilot project. The model development included steps I and II of the pilot project, identification of the service types, a survey exploring the community demand for palliative care, construction of an operational infrastructure, and the establishment of a service delivery system. Public health centers (including Busan regional cancer centers, palliative care centers, and social welfare centers) served as the regional hubs in the development of a palliative care model. The palliative care project included the provision of palliative care, establishment of a support system for the operations, improvement of personnel capacity, development of an educational and promotional program, and the establishment of an assessment system to improve quality. The operational infrastructure included a service management team, provision teams, and a support team. The Busan Metropolitan City CBPC model was based on the principles of palliative care as well as the characteristics of public health centers that implemented the community health projects. The potential use of the Busan CBPC model in Korea should be explored further through service evaluations.

Using a new high resolution regional model for malaria that accounts for population density and surface hydrology to determine sensitivity of malaria risk to climate drivers

NASA Astrophysics Data System (ADS)

Tompkins, Adrian; Ermert, Volker; Di Giuseppe, Francesca

2013-04-01

In order to better address the role of population dynamics and surface hydrology in the assessment of malaria risk, a new dynamical disease model been developed at ICTP, known as VECTRI: VECtor borne disease community model of ICTP, TRIeste (VECTRI). The model accounts for the temperature impact on the larvae, parasite and adult vector populations. Local host population density affects the transmission intensity, and the model thus reproduces the differences between peri-urban and rural transmission noted in Africa. A new simple pond model framework represents surface hydrology. The model can be used on with spatial resolutions finer than 10km to resolve individual health districts and thus can be used as a planning tool. Results of the models representation of interannual variability and longer term projections of malaria transmission will be shown for Africa. These will show that the model represents the seasonality and spatial variations of malaria transmission well matching a wide range of survey data of parasite rate and entomological inoculation rate (EIR) from across West and East Africa taken in the period prior to large-scale interventions. The model is used to determine the sensitivity of malaria risk to climate variations, both in rainfall and temperature, and then its use in a prototype forecasting system coupled with ECMWF forecasts will be demonstrated.

Target prioritization and strategy selection for active case-finding of pulmonary tuberculosis: a tool to support country-level project planning.

PubMed

Nishikiori, Nobuyuki; Van Weezenbeek, Catharina

2013-02-02

Despite the progress made in the past decade, tuberculosis (TB) control still faces significant challenges. In many countries with declining TB incidence, the disease tends to concentrate in vulnerable populations that often have limited access to health care. In light of the limitations of the current case-finding approach and the global urgency to improve case detection, active case-finding (ACF) has been suggested as an important complementary strategy to accelerate tuberculosis control especially among high-risk populations. The present exercise aims to develop a model that can be used for county-level project planning. A simple deterministic model was developed to calculate the number of estimated TB cases diagnosed and the associated costs of diagnosis. The model was designed to compare cost-effectiveness parameters, such as the cost per case detected, for different diagnostic algorithms when they are applied to different risk populations. The model was transformed into a web-based tool that can support national TB programmes and civil society partners in designing ACF activities. According to the model output, tuberculosis active case-finding can be a costly endeavor, depending on the target population and the diagnostic strategy. The analysis suggests the following: (1) Active case-finding activities are cost-effective only if the tuberculosis prevalence among the target population is high. (2) Extensive diagnostic methods (e.g. X-ray screening for the entire group, use of sputum culture or molecular diagnostics) can be applied only to very high-risk groups such as TB contacts, prisoners or people living with human immunodeficiency virus (HIV) infection. (3) Basic diagnostic approaches such as TB symptom screening are always applicable although the diagnostic yield is very limited. The cost-effectiveness parameter was sensitive to local diagnostic costs and the tuberculosis prevalence of target populations. The prioritization of appropriate target populations and careful selection of cost-effective diagnostic strategies are critical prerequisites for rational active case-finding activities. A decision to conduct such activities should be based on the setting-specific cost-effectiveness analysis and programmatic assessment. A web-based tool was developed and is available to support national tuberculosis programmes and partners in the formulation of cost-effective active case-finding activities at the national and subnational levels.

Projected distributions and diversity of flightless ground beetles within the Australian Wet Tropics and their environmental correlates.

PubMed

Staunton, Kyran M; Robson, Simon K A; Burwell, Chris J; Reside, April E; Williams, Stephen E

2014-01-01

With the impending threat of climate change, greater understanding of patterns of species distributions and richness and the environmental factors driving them are required for effective conservation efforts. Species distribution models enable us to not only estimate geographic extents of species and subsequent patterns of species richness, but also generate hypotheses regarding environmental factors determining these spatial patterns. Projected changes in climate can then be used to predict future patterns of species distributions and richness. We created distribution models for most of the flightless ground beetles (Carabidae) within the Wet Tropics World Heritage Area of Australia, a major component of regionally endemic invertebrates. Forty-three species were modelled and the environmental correlates of these distributions and resultant patterns of species richness were examined. Flightless ground beetles generally inhabit upland areas characterised by stable, cool and wet environmental conditions. These distribution and richness patterns are best explained using the time-stability hypothesis as this group's primary habitat, upland rainforest, is considered to be the most stable regional habitat. Projected changes in distributions indicate that as upward shifts in distributions occur, species currently confined to lower and drier mountain ranges will be more vulnerable to climate change impacts than those restricted to the highest and wettest mountains. Distribution models under projected future climate change suggest that there will be reductions in range size, population size and species richness under all emission scenarios. Eighty-eight per cent of species modelled are predicted to decline in population size by over 80%, for the most severe emission scenario by the year 2080. These results suggest that flightless ground beetles are among the most vulnerable taxa to climate change impacts so far investigated in the Wet Tropics World Heritage Area. These findings have dramatic implications for all other flightless insect taxa and the future biodiversity of this region.

Projected Distributions and Diversity of Flightless Ground Beetles within the Australian Wet Tropics and Their Environmental Correlates

PubMed Central

Staunton, Kyran M.; Robson, Simon K. A.; Burwell, Chris J.; Reside, April E.; Williams, Stephen E.

2014-01-01

With the impending threat of climate change, greater understanding of patterns of species distributions and richness and the environmental factors driving them are required for effective conservation efforts. Species distribution models enable us to not only estimate geographic extents of species and subsequent patterns of species richness, but also generate hypotheses regarding environmental factors determining these spatial patterns. Projected changes in climate can then be used to predict future patterns of species distributions and richness. We created distribution models for most of the flightless ground beetles (Carabidae) within the Wet Tropics World Heritage Area of Australia, a major component of regionally endemic invertebrates. Forty-three species were modelled and the environmental correlates of these distributions and resultant patterns of species richness were examined. Flightless ground beetles generally inhabit upland areas characterised by stable, cool and wet environmental conditions. These distribution and richness patterns are best explained using the time-stability hypothesis as this group’s primary habitat, upland rainforest, is considered to be the most stable regional habitat. Projected changes in distributions indicate that as upward shifts in distributions occur, species currently confined to lower and drier mountain ranges will be more vulnerable to climate change impacts than those restricted to the highest and wettest mountains. Distribution models under projected future climate change suggest that there will be reductions in range size, population size and species richness under all emission scenarios. Eighty-eight per cent of species modelled are predicted to decline in population size by over 80%, for the most severe emission scenario by the year 2080. These results suggest that flightless ground beetles are among the most vulnerable taxa to climate change impacts so far investigated in the Wet Tropics World Heritage Area. These findings have dramatic implications for all other flightless insect taxa and the future biodiversity of this region. PMID:24586362

Community-based Participatory Research

PubMed Central

Holkup, Patricia A.; Tripp-Reimer, Toni; Salois, Emily Matt; Weinert, Clarann

2009-01-01

Community-based participatory research (CBPR), with its emphasis on joining with the community as full and equal partners in all phases of the research process, makes it an appealing model for research with vulnerable populations. However, the CBPR approach is not without special challenges relating to ethical, cultural, and scientific issues. In this article, we describe how we managed the challenges we encountered while conducting a CBPR project with a Native American community. We also suggest criteria that will enable evaluation of the project. PMID:15455579

A system dynamics modelling approach to assess the impact of launching a new nicotine product on population health outcomes.

PubMed

Hill, Andrew; Camacho, Oscar M

2017-06-01

In 2012 the US FDA suggested the use of mathematical models to assess the impact of releasing new nicotine or tobacco products on population health outcomes. A model based on system dynamics methodology was developed to project the potential effects of a new nicotine product at a population level. A model representing traditional smoking populations (never, current and former smokers) and calibrated using historical data was extended to a two-product model by including electronic cigarettes use statuses. Smoking mechanisms, such as product initiation, switching, transition to dual use, and cessation, were represented as flows between smoking statuses (stocks) and the potential effect of smoking renormalisation through a feedback system. Mortality over a 50-year period (2000-2050) was the health outcome of interest, and was compared between two scenarios, with and without e-cigarettes being introduced. The results suggest that by 2050, smoking prevalence in adults was 12.4% in the core model and 9.7% (including dual users) in the counterfactual. Smoking-related mortality was 8.4% and 8.1%, respectively. The results suggested an overall beneficial effect from launching e-cigarettes and that system dynamics could be a useful approach to assess the potential population health effects of nicotine products when epidemiological data are not available. Copyright © 2017 The Authors. Published by Elsevier Inc. All rights reserved.

Estimation of a genetically viable population for multigenerational interstellar voyaging: Review and data for project Hyperion

NASA Astrophysics Data System (ADS)

Smith, Cameron M.

2014-04-01

Designing interstellar starships for human migration to exoplanets requires establishing the starship population, which factors into many variables including closed-ecosystem design, architecture, mass and propulsion. I review the central issues of population genetics (effects of mutation, migration, selection and drift) for human populations on such voyages, specifically referencing a roughly 5-generation (c. 150-year) voyage currently in the realm of thought among Icarus Interstellar's Project Hyperion research group. I present several formulae as well as concrete numbers that can be used to help determine populations that could survive such journeys in good health. I find that previously proposed such populations, on the order of a few hundred individuals, are significantly too low to consider based on current understanding of vertebrate (including human) genetics and population dynamics. Population genetics theory, calculations and computer modeling determine that a properly screened and age- and sex-structured total founding population (Nc) of anywhere from roughly 14,000 to 44,000 people would be sufficient to survive such journeys in good health. A safe and well-considered Nc figure is 40,000, an Interstellar Migrant Population (IMP) composed of an Effective Population [Ne] of 23,400 reproductive males and females, the rest being pre- or post-reproductive individuals. This number would maintain good health over five generations despite (a) increased inbreeding resulting from a relatively small human population, (b) depressed genetic diversity due to the founder effect, (c) demographic change through time and (d) expectation of at least one severe population catastrophe over the 5-generation voyage.

Stochastic agent-based modeling of tuberculosis in Canadian Indigenous communities.

PubMed

Tuite, Ashleigh R; Gallant, Victor; Randell, Elaine; Bourgeois, Annie-Claude; Greer, Amy L

2017-01-13

In Canada, active tuberculosis (TB) disease rates remain disproportionately higher among the Indigenous population, especially among the Inuit in the north. We used mathematical modeling to evaluate how interventions might enhance existing TB control efforts in a region of Nunavut. We developed a stochastic, agent-based model of TB transmission that captured the unique household and community structure. Evaluated interventions included: (i) rapid treatment of active cases; (ii) rapid contact tracing; (iii) expanded screening programs for latent TB infection (LTBI); and (iv) reduced household density. The outcomes of interest were incident TB infections and total diagnosed active TB disease over a 10- year time period. Model-projected incidence in the absence of additional interventions was highly variable (range: 33-369 cases) over 10 years. Compared to the 'no additional intervention' scenario, reducing the time between onset of active TB disease and initiation of treatment reduced both the number of new TB infections (47% reduction, relative risk of TB = 0.53) and diagnoses of active TB disease (19% reduction, relative risk of TB = 0.81). Expanding general population screening was also projected to reduce the burden of TB, although these findings were sensitive to assumptions around the relative amount of transmission occurring outside of households. Other potential interventions examined in the model (school-based screening, rapid contact tracing, and reduced household density) were found to have limited effectiveness. In a region of northern Canada experiencing a significant TB burden, more rapid treatment initiation in active TB cases was the most impactful intervention evaluated. Mathematical modeling can provide guidance for allocation of limited resources in a way that minimizes disease transmission and protects population health.

Population viability analysis for endangered Roanoke logperch

USGS Publications Warehouse

Roberts, James H.; Angermeier, Paul; Anderson, Gregory B.

2016-01-01

A common strategy for recovering endangered species is ensuring that populations exceed the minimum viable population size (MVP), a demographic benchmark that theoretically ensures low long-term extinction risk. One method of establishing MVP is population viability analysis, a modeling technique that simulates population trajectories and forecasts extinction risk based on a series of biological, environmental, and management assumptions. Such models also help identify key uncertainties that have a large influence on extinction risk. We used stochastic count-based simulation models to explore extinction risk, MVP, and the possible benefits of alternative management strategies in populations of Roanoke logperch Percina rex, an endangered stream fish. Estimates of extinction risk were sensitive to the assumed population growth rate and model type, carrying capacity, and catastrophe regime (frequency and severity of anthropogenic fish kills), whereas demographic augmentation did little to reduce extinction risk. Under density-dependent growth, the estimated MVP for Roanoke logperch ranged from 200 to 4200 individuals, depending on the assumed severity of catastrophes. Thus, depending on the MVP threshold, anywhere from two to all five of the logperch populations we assessed were projected to be viable. Despite this uncertainty, these results help identify populations with the greatest relative extinction risk, as well as management strategies that might reduce this risk the most, such as increasing carrying capacity and reducing fish kills. Better estimates of population growth parameters and catastrophe regimes would facilitate the refinement of MVP and extinction-risk estimates, and they should be a high priority for future research on Roanoke logperch and other imperiled stream-fish species.

A statistical framework for the validation of a population exposure model based on personal exposure data

NASA Astrophysics Data System (ADS)

Rodriguez, Delphy; Valari, Myrto; Markakis, Konstantinos; Payan, Sébastien

2016-04-01

Currently, ambient pollutant concentrations at monitoring sites are routinely measured by local networks, such as AIRPARIF in Paris, France. Pollutant concentration fields are also simulated with regional-scale chemistry transport models such as CHIMERE (http://www.lmd.polytechnique.fr/chimere) under air-quality forecasting platforms (e.g. Prev'Air http://www.prevair.org) or research projects. These data may be combined with more or less sophisticated techniques to provide a fairly good representation of pollutant concentration spatial gradients over urban areas. Here we focus on human exposure to atmospheric contaminants. Based on census data on population dynamics and demographics, modeled outdoor concentrations and infiltration of outdoor air-pollution indoors we have developed a population exposure model for ozone and PM2.5. A critical challenge in the field of population exposure modeling is model validation since personal exposure data are expensive and therefore, rare. However, recent research has made low cost mobile sensors fairly common and therefore personal exposure data should become more and more accessible. In view of planned cohort field-campaigns where such data will be available over the Paris region, we propose in the present study a statistical framework that makes the comparison between modeled and measured exposures meaningful. Our ultimate goal is to evaluate the exposure model by comparing modeled exposures to monitor data. The scientific question we address here is how to downscale modeled data that are estimated on the county population scale at the individual scale which is appropriate to the available measurements. To assess this question we developed a Bayesian hierarchical framework that assimilates actual individual data into population statistics and updates the probability estimate.

Bird response to future climate and forest management focused on mitigating climate change

Treesearch

Jaymi J. LeBrun; Jeffrey E. Schneiderman; Frank R. Thompson; William D. Dijak; Jacob S. Fraser; Hong S. He; Joshua J. Millspaugh

2016-01-01

Context. Global temperatures are projected to increase and affect forests and wildlife populations. Forest management can potentially mitigate climateinduced changes through promoting carbon sequestration, forest resilience, and facilitated change. Objectives. We modeled direct and indirect effects of climate change on avian...

Early College High Schools: Model Policy Components. Policy Analysis

ERIC Educational Resources Information Center

Zinth, Jennifer

2016-01-01

An alarming convergence of factors--diminishing percentages of high school graduates enrolling immediately in postsecondary education, traditionally underserved students comprising a growing proportion of the overall U.S. school population, and projections that more occupations in the future will need education beyond high school--suggest that…

Environmental Biosciences Program Quarterly Report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lawrence C. Mohr, M.D.

2009-01-30

Current research projects have focused Environmental Biosciences Program (EBP) talent and resources on providing the scientific basis for risk-based standards, risk-based decision making and the accelerated clean-up of widespread environmental hazards. These hazards include trichloroethylene, low-dose ionizing radiation (gamma and neutron) and alpha radiation from plutonium. Trichloroethylene research has been conducted as a joint collaborative effort with the University of Georgia. Work on the trichloroethylene research projects has been slowed as a result of funding uncertainties. The impact of these funding uncertainties has been discussed with the United States Department of Energy (DOE). Laboratory work has been completed on severalmore » trichloroethylene risk assessment projects, and these projects have been brought to a close. Plans for restructuring the performance schedule of the remaining trichloroethylene projects have been submitted to the department. A comprehensive manuscript on the scientific basis of trichloroethylene risk assessment is in preparation. Work on the low-dose radiation risk assessment projects is also progressing at a slowed rate as a result of funding uncertainties. It has been necessary to restructure the proponency and performance schedule of these projects, with the project on Low-Dose Radiation: Epidemiology Risk Models transferred to DOE Office of Science proponency under a separate funding instrument. Research on this project will continue under the provisions of the DOE Office of Science funding instrument, with progress reported in accordance with the requirements of that funding instrument. Progress on that project will no longer be reported in quarterly reports for DE-FC09-02CH11109. Following a meeting at the Savannah River Site on May 8, 2008, a plan was submitted for development of an epidemiological cohort study and prospective medical surveillance system for the assessment of disease rates among workers at the Savannah River Site (SRS). This project will be incorporated into the ongoing project on Population Health Risks in the Vicinity of the Savannah River Site. During a meeting at the SRS on October 21, 2008, a presentation was made on EBP participation in the development and operation of an Epidemiology Consortium at the SRS. A follow-up meeting with SRS officials is planned for 29 and 30 January 2009 at Medical University of South Carolina (MUSC).An epidemiology project on population health risk assessment is being conducted to assess health risks among populations in the vicinity of the SRS. This project is using the capabilities of the EBP GIS for the geographical assessment of cancer and non-cancer disease rates, as well as the potential association of population health risks with environmental exposures. Although funding uncertainties have slowed progress on some aspects of this project, it has not been necessary to restructure the performance schedule to date.« less

United Nations population estimates and projections with special reference to the Arab world.

PubMed

1980-06-01

The United Nations Population Division has been preparing world population estimates and projections by region since 1951, by country since 1958, and by sex and age for each country since 1968. The latest revision of the projections was prepared in 1978. The 2 basic methods of preparing population projections are mathematical and component, and the component methods are most widely used at present, by both national governments and the United Nations. Before projections are prepared, the base data must be evaluated and adjusted. In the UN projections, the assumptions imply that orderly progress will be made and that there will be no catastrophes such as famines and epidemics during the projection period. The projectins are prepared in 4 variants--"medium", "high," "low," and "constant." A major source of uncertainty in populations arises from the problem of estimating future fertility. Changes in fertility affect the age distribution and the total population size more than changes in mortality. At the UN, mortality assumptions are initially made in terms of life expectancy at birth and then in terms of age-sex patterns of probabilities of survival corresponding to different life expectancy levels at birth. Some of the results of the 1978 revision of the medium variant of the estimates and projections are shown in table form. The world total population of 4,033,000,000 in 1975 is projected to reach 6,199,000,000 by the year 2000. Among the major areas and regions of the world, the most rapid population growth for the future is projected for the Arab countries, Africa and Latin America. Of the 2 Arab regions, North Africa and Southwest Asia, Southwest Asia is expected to have the higher rate of growth because of assumed continued immigration. Within the Arab regions, there has been an increasing diversity in the rate of population growth. This divergence is expected to narrow with assumed decreased migration rates during the 1980s.

Population Projections

Science.gov Websites

United States Census Bureau Topics Population Latest Information Age and Sex Ancestry Children Mobility Population Estimates Population Projections Race Veterans Economy Latest Information Portal Other Economic Programs Business Latest Information Business Characteristics Classification Codes

[Statistical surveys].

PubMed

1981-01-01

Data are included on fertility and mortality projections for Czechoslovakia, 1981-2000; population projections, 1981-2000; population of reproductive age, 1981-2000; and natural growth of population, 1975-1980

Interim 2003-based national population projections for the United Kingdom and constituent countries.

PubMed

Shaw, Chris

2004-01-01

The 2003-based national population projections, carried out by the Government Actuary in consultation with the Registrars General, and using essentially the same underlying assumptions as for the previous 2002-based projections, show the population of the United Kingdom rising from 59.6 million in 2003, passing 60 million during 2005, to reach 65.7 million by 2031. Longer-term projections suggest the population will peak around 2050 at nearly 67 million and then very gradually start to fall. The population will become older with the median age expected to rise from 38.4 years in 2003 to 43.3 years by 2031. In 2003, there were around 700 thousand (six per cent) more children aged under 16, than people of state pensionable age. However, from 2007, the population of pensionable age is projected to exceed the number of children.

Application of the stage-projection model with density-dependent fecundity to the population dynamics of Spanish ibex

USGS Publications Warehouse

Escos, J.; Alados, C.L.; Emlen, John M.

1994-01-01

A stage-class population model with density-feedback term included was used to identify the most critical parameters determining the population dynamics of female Spanish ibex (Capra pyrenaica) in southern Spain. A population in the Cazorla and Segura mountains is rapidly declining, but the eastern Sierra Nevada population is growing. The stable population density obtained using estimated values of kid and adult survival (0.49 and 0.87, respectively) and with fecundity equal to 0.367 in the absence of density feedback is 12.7 or 16.82 individuals/km2, based on a non-time-lagged and a time-lagged model, respectively. Given the maximum estimate of fecundity and an adult survival rate of 0.87, a kid survival rate of at least 0.41 is required to avoid extinction. At the minimum fecundity estimate, kid survival would have to exceed 0.52. Elasticities were used to estimate the influence of variation in life-cycle parameters on the intrinsic rate of increase. Adult survival is the most critical parameter, while fecundity and juvenile survival are less important. An increase in adult survival from 0.87 to 0.91 in the Cazorla and Segura mountains population would almost stabilize the population in the absence of stochastic variation, while the same increase in the Sierra Nevada population would yield population growth of 4–5% per annum. A reduction in adult survival to 0.83 results in population decline in both cases.

Avoiding verisimilitude when modelling ecological responses to climate change: the influence of weather conditions on trapping efficiency in European badgers (Meles meles).

PubMed

Noonan, Michael J; Rahman, M Abidur; Newman, Chris; Buesching, Christina D; Macdonald, David W

2015-10-01

The signal for climate change effects can be abstruse; consequently, interpretations of evidence must avoid verisimilitude, or else misattribution of causality could compromise policy decisions. Examining climatic effects on wild animal population dynamics requires ability to trap, observe or photograph and to recapture study individuals consistently. In this regard, we use 19 years of data (1994-2012), detailing the life histories on 1179 individual European badgers over 3288 (re-) trapping events, to test whether trapping efficiency was associated with season, weather variables (both contemporaneous and time lagged), body-condition index (BCI) and trapping efficiency (TE). PCA factor loadings demonstrated that TE was affected significantly by temperature and precipitation, as well as time lags in these variables. From multi-model inference, BCI was the principal driver of TE, where badgers in good condition were less likely to be trapped. Our analyses exposed that this was enacted mechanistically via weather variables driving BCI, affecting TE. Notably, the very conditions that militated for poor trapping success have been associated with actual survival and population abundance benefits in badgers. Using these findings to parameterize simulations, projecting best-/worst-case scenario weather conditions and BCI resulted in 8.6% ± 4.9 SD difference in seasonal TE, leading to a potential 55.0% population abundance under-estimation under the worst-case scenario; 38.6% over-estimation under the best case. Interestingly, simulations revealed that while any single trapping session might prove misrepresentative of the true population abundance, due to weather effects, prolonging capture-mark-recapture studies under sub-optimal conditions decreased the accuracy of population estimates significantly. We also use these projection scenarios to explore how weather could impact government-led trapping of badgers in the UK, in relation to TB management. We conclude that population monitoring must be calibrated against the likelihood that weather conditions could be altering trap success directly, and therefore biasing model design. © 2015 John Wiley & Sons Ltd.

Projecting population change in the interior Columbia River Basin.

Treesearch

Stephen F. McCool; Richard W. Haynes

1996-01-01

Management of ecosystems requires projecting the human population for a biologically significant timeframe, because the impacts of potential alternative ecosystem management strategies will differ depending on the size, location, and expectations of the human population. Increases since 1990 in the net migration rates are changing the expectations for projections of...

Impact of forestry practices at a landscape scale on the dynamics of amphibian populations.

PubMed

Harper, Elizabeth B; Patrick, David A; Gibbs, James P

2015-12-01

Forest loss is a primary cause of worldwide amphibian decline. Timber harvesting in the United States has caused dramatic changes in quality and extent of forest ecosystems, and intensive forest management still occurs. Although numerous studies have documented substantial reductions in amphibian densities related to timber harvest, subsequent extinctions are rare. To better understand the population dynamics that have allowed so many amphibian species to persist in the face of widespread forest disturbance, we developed spatially explicit metapopulation models for four forest-dependent amphibian species (Lithobates sylvaticus, Ambystoma opacum, A. talpoideum, and A. maculatum) that incorporated demographic and habitat selection data derived from experiments conducted as part of the Land Use Effects on Amphibian Populations Project (LEAP). We projected local and landscape-scale population persistence under 108 different forestry practice scenarios, varying treatment (partial cut, clear-cut with coarse woody debris [CWD] removed, and clearcut with CWD retained), cut patch size (1, 10, or 50 ha), total area cut (10, 20, or 30%), and initial amphibian population size (5, 50, or 500 adult females per local breeding population). Under these scenarios, landscape-scale extinction was highly unlikely, occurring in < 1% of model runs and for only 2 of the 4 species, because landscape-scale populations were able to persist via dispersal even despite frequent local extinctions. Yet for all species, population sizes were reduced to -50% in all clear-cut scenarios, regardless of the size of harvested patches. These findings suggest that debate over timber harvesting on pool-breeding amphibian populations in the United States should focus not on questions of landscape-scale extinction but on the ecological consequences of dramatic reductions in amphibian biomass, including changes in trophic interactions, nutrient cycling, and energy transfer. Additionally, we conclude that amphibian declines and extinctions are far more likely to occur as a result of permanent habitat loss resulting from development than from the temporary degradation of habitat caused by current forestry practices.

2002-based national population projections for the United Kingdom and constituent countries.

PubMed

Shaw, Chris

2004-01-01

The 2002-based national population projections, carried out by the Government Actuary in consultation with the Registrars General, show the population of the United Kingdom rising from 59.2 million in 2002 to nearly 65 million by 2031. Longer-term projections suggest the population will peak around 2050 at over 65 million and then gradually start to fall. The population will become gradually older with the median age expected to rise from 38.2 years in 2002 to 43.3 years by 2031. In 2002, there were around 850 thousand (8 per cent) more children aged under 16, than people of state pensionable age. However, from 2007, the population of pensionable age is projected to exceed the number of children.

2000-based national population projections for the United Kingdom and its constituent countries.

PubMed

Shaw, Chris

2002-01-01

The 2000-based national population projections, carried out by the Government Actuary at the request of the Registrars General, show the population of the United Kingdom rising from 59.8 million in 2000 to nearly 65 million by 2025. Longer-term projections suggest the population will peak at nearly 66 million around 2040 and then gradually start to fall. The population will become gradually older with the median age expected to rise from 37.4 years in 2000 to 42.4 years by 2025. In 2000, there were 1.3 million (12 per cent) more children aged under 16, than people of state pensionable age. However, by 2007, the population of state pensionable age is projected to exceed the number of children.

1998-based national population projections for the United Kingdom and constituent countries.

PubMed

Shaw, C

2000-01-01

The 1998-based national population projections, carried out by the Government Actuary in consultation with the Registrars General, show the population of the United Kingdom rising from 59.2 million in 1998 to over 63.5 million by 2021. Longer-term projections suggest the population will peak around 2036 and then gradually start to fall. The population will become gradually older with the median age expected to rise from 36.9 years in 1998 to nearly 42 years by 2021. In 1998, there were 1.4 million (13 per cent) more children aged under 16, than people of pensionable age. However, by 2008, the population of pensionable age is projected to exceed the number of children.

Childhood Obesity Research Demonstration Project: Cross-Site Evaluation Methods

PubMed Central

Lee, Rebecca E.; Mehta, Paras; Thompson, Debbe; Bhargava, Alok; Carlson, Coleen; Kao, Dennis; Layne, Charles S.; Ledoux, Tracey; O'Connor, Teresia; Rifai, Hanadi; Gulley, Lauren; Hallett, Allen M.; Kudia, Ousswa; Joseph, Sitara; Modelska, Maria; Ortega, Dana; Parker, Nathan; Stevens, Andria

2015-01-01

Abstract Introduction: The Childhood Obesity Research Demonstration (CORD) project links public health and primary care interventions in three projects described in detail in accompanying articles in this issue of Childhood Obesity. This article describes a comprehensive evaluation plan to determine the extent to which the CORD model is associated with changes in behavior, body weight, BMI, quality of life, and healthcare satisfaction in children 2–12 years of age. Design/Methods: The CORD Evaluation Center (EC-CORD) will analyze the pooled data from three independent demonstration projects that each integrate public health and primary care childhood obesity interventions. An extensive set of common measures at the family, facility, and community levels were defined by consensus among the CORD projects and EC-CORD. Process evaluation will assess reach, dose delivered, and fidelity of intervention components. Impact evaluation will use a mixed linear models approach to account for heterogeneity among project-site populations and interventions. Sustainability evaluation will assess the potential for replicability, continuation of benefits beyond the funding period, institutionalization of the intervention activities, and community capacity to support ongoing program delivery. Finally, cost analyses will assess how much benefit can potentially be gained per dollar invested in programs based on the CORD model. Conclusions: The keys to combining and analyzing data across multiple projects include the CORD model framework and common measures for the behavioral and health outcomes along with important covariates at the individual, setting, and community levels. The overall objective of the comprehensive evaluation will develop evidence-based recommendations for replicating and disseminating community-wide, integrated public health and primary care programs based on the CORD model. PMID:25679060

ProjectHeartforGirls.com: Development of a Web-Based HIV/STD Prevention Program for Adolescent Girls Emphasizing Sexual Communication Skills.

PubMed

Widman, Laura; Golin, Carol E; Noar, Seth M; Massey, Joy; Prinstein, Mitchell J

2016-10-01

This article describes the development of ProjectHeartforGirls.com , an interactive web-based program designed to improve sexual communication skills and reduce the risk of HIV/STDs among adolescent girls, a population at heightened risk for negative sexual health outcomes (Centers for Disease Control and Prevention, 2013). Although sexual communication is a critical predictor of safer sex among teens, there are few online interventions that target these skills as a central program component. We developed ProjectHeartforGirls.com to fill this gap. Program development involved (1) identifying the target population (ethnically diverse high school girls), (2) clarifying the theoretical foundation (Reasoned Action Model), (3) conducting formative qualitative research (n = 25 girls), (4) drafting initial program content, (5) receiving ongoing feedback from a teen advisory board (n = 5 girls), (6) programming online content, and (7) conducting usability testing (n = 6 girls). These steps are described along with the final intervention product, which is currently being evaluated in a randomized controlled trial.

ProjectHeartForGirls.com: Development of a web-based HIV/STD prevention program for adolescent girls emphasizing sexual communication skills

PubMed Central

Widman, Laura; Golin, Carol E.; Noar, Seth M.; Massey, Joy; Prinstein, Mitchell J.

2017-01-01

This article describes the development of ProjectHeartforGirls.com, an interactive web-based program designed to improve sexual communication skills and reduce the risk of HIV/STDs among adolescent girls, a population at heightened risk for negative sexual health outcomes (CDC, 2013). Although sexual communication is a critical predictor of safer sex among teens, there are few online interventions that target these skills as a central program component. We developed ProjectHeartforGirls.com to fill this gap. Program development involved 1) identifying the target population (ethnically-diverse high school girls); 2) clarifying the theoretical foundation (Reasoned Action Model); 3) conducting formative qualitative research (n=25 girls); 4) drafting initial program content; 5) receiving ongoing feedback from a teen advisory board (n=5 girls); 6) programming online content; and 7) conducting usability testing (n=6 girls). These steps are described along with the final intervention product, which is currently being evaluated in a randomized controlled trial. PMID:27710087

Quantifying Future PM2.5 and Associated Health Effects Due to Changes in US Wildfires

NASA Astrophysics Data System (ADS)

Pierce, J. R.; Val Martin, M.; Ford, B.; Zelasky, S.; Heald, C. L.; Li, F.; Lawrence, D. M.; Fischer, E. V.

2017-12-01

Fine particulate matter (PM2.5) from landscape fires has been shown to adversely affect visibility, air quality and and health across the US. Fire activity is strongly related to climate and human activities. Predictions based on climate scenarios and future land cover projections that consider socioeconomic development suggest that fire activity will rise dramatically over the next decades. As PM2.5 is associated with increased mortality and morbidity rates, increases in emissions from landscape fires may alter the health burden on the US population. Here we present an analysis of the changes in future wildfire activity and consequences for PM2.5 and health over the US from 2000 to 2100. We employ the global Community Earth System Model (CESM) with the IPCC RCP projections. Within CESM, we use a process-based global fire parameterization to project future climate-driven and human-caused fire emissions. From these simulations, we determine the current and future impact on PM2.5 concentrations and visibility for different regions of the US, and we also calculate the mortality attributable to PM2.5 and wildfire-specific PM2.5 using existing concentration-response functions. Results show that although total PM2.5 concentrations in the US are projected to be similar in 2100 as in 2000, the dominant source of PM2.5 will change. Under the RCP8.5 climate projection and SSP3 population projection, non-fire emissions (mostly anthropogenic) are projected to decrease, but PM2.5 from CONUS and non-US wildfires is projected to increase from approximately 20% of all PM2.5 in 2000 to 80% of all PM2.5 in 2100. Furthermore, although the US population is expected to decline between 2000 and 2100, the mortality attributable to wildfire smoke is expected to increase from 25,000 deaths per year in 2000 to 75,000 deaths per year in 2100.

An injury prevention strategy for teen restaurant workers. Washington State's ProSafety project.

PubMed

Ward, Julie A; de Castro, A B; Tsai, Jenny Hsin-Chun; Linker, Darren; Hildahl, Lyle; Miller, Mary E

2010-02-01

High levels of youth employment, workplace hazards, and characteristics unique to adolescents contribute to a relatively high incidence of injuries among teens in the restaurant industry. This article discusses the ProSafety model of injury prevention among teen restaurant workers. Through integration with an existing career and technical education program, the ProSafety project seeks to prevent occupational injuries among the teen worker population through classroom safety education and internship skills reinforcement. ProSafety is the product of an innovative collaboration with occupational health nurses, business professionals, educators, and government. Its approach is derived from Social Cognitive Theory, is consistent with key values and strategies of occupational health nurses, and provides lessons for practitioners seeking to reduce occupational injuries in food service or among other populations of adolescent workers.

[Implementing models of cross-sectoral mental health care (integrated health care, regional psychiatry budget) in Germany: systematic literature review].

PubMed

Schmid, Petra; Steinert, Tilman; Borbé, Raoul

2013-11-01

Cross-sectoral integrated health-care and the regional psychiatry budget are two models of cross-sectoral health care (comprising in-patient and out-patient care) in Germany. Both models of financing were created in order to overcome the so-called fragmentation in German health care. The regional psychiatry budget is a specific solution for psychiatric services whereas integrated health care models can be developed for all areas of health care. The purpose of this overview is to elucidate both the current state of implementation of these models and the results of evaluation research. Systematic literature review, additional manual search. 28 journal articles and 38 websites referring to 21 projects were identified. The projects are highly heterogenuous in terms of size, included populations and services, aims, and steering-function (concerning the different pathways of care). The projects yield innovative models of mental health care capable of competing with the co-existing traditional financing systems of in-patient and out-patient services. The future of mental health care organisation in Germany is currently open and under political discussion. © Georg Thieme Verlag KG Stuttgart · New York.

Population viability analysis: using a modeling tool to assess the viability of tapir populations in fragmented landscapes.

PubMed

Medici, Emília Patrícia; Desbiez, Arnaud Leonard Jean

2012-12-01

A population viability analysis (PVA) was conducted of the lowland tapir populations in the Atlantic Forest of the Pontal do Paranapanema region, Brazil, including Morro do Diabo State Park (MDSP) and surrounding forest fragments. Results from the model projected that the population of 126 tapirs in MDSP is likely to persist over the next 100 years; however, 200 tapirs would be required to maintain a viable population. Sensitivity analysis showed that sub-adult mortality and adult mortality have the strongest influence on the dynamics of lowland tapir populations. High road-kill has a major impact on the MDSP tapir population and can lead to population extinction. Metapopulation modeling showed that dispersal of tapirs from MDSP to the surrounding fragments can be detrimental to the overall metapopulation, as fragments act as sinks. Nevertheless, the model showed that under certain conditions the maintenance of the metapopulation dynamics might be determinant for the persistence of tapirs in the region, particularly in the smaller fragments. The establishment of corridors connecting MDSP to the forest fragments models resulted in an increase in the stochastic growth rate, making tapirs more resilient to threats and catastrophes, but only if rates of mortality were not increased when using corridors. The PVA showed that the conservation of tapirs in the Pontal region depends on: the effective protection of MDSP; maintenance and, whenever possible, enhancement of the functional connectivity of the landscape, reducing mortality during dispersal and threats in the unprotected forest fragments; and neutralization of all threats affecting tapirs in the smaller forest fragments. © 2012 Wiley Publishing Asia Pty Ltd, ISZS and IOZ/CAS.

Policy evaluation in diabetes prevention and treatment using a population-based macro simulation model: the MICADO model.

PubMed

van der Heijden, A A W A; Feenstra, T L; Hoogenveen, R T; Niessen, L W; de Bruijne, M C; Dekker, J M; Baan, C A; Nijpels, G

2015-12-01

To test a simulation model, the MICADO model, for estimating the long-term effects of interventions in people with and without diabetes. The MICADO model includes micro- and macrovascular diseases in relation to their risk factors. The strengths of this model are its population scope and the possibility to assess parameter uncertainty using probabilistic sensitivity analyses. Outcomes include incidence and prevalence of complications, quality of life, costs and cost-effectiveness. We externally validated MICADO's estimates of micro- and macrovascular complications in a Dutch cohort with diabetes (n = 498,400) by comparing these estimates with national and international empirical data. For the annual number of people undergoing amputations, MICADO's estimate was 592 (95% interquantile range 291-842), which compared well with the registered number of people with diabetes-related amputations in the Netherlands (728). The incidence of end-stage renal disease estimated using the MICADO model was 247 people (95% interquartile range 120-363), which was also similar to the registered incidence in the Netherlands (277 people). MICADO performed well in the validation of macrovascular outcomes of population-based cohorts, while it had more difficulty in reflecting a highly selected trial population. Validation by comparison with independent empirical data showed that the MICADO model simulates the natural course of diabetes and its micro- and macrovascular complications well. As a population-based model, MICADO can be applied for projections as well as scenario analyses to evaluate the long-term (cost-)effectiveness of population-level interventions targeting diabetes and its complications in the Netherlands or similar countries. © 2015 The Authors. Diabetic Medicine © 2015 Diabetes UK.

A regional-scale, high resolution dynamical malaria model that accounts for population density, climate and surface hydrology.

PubMed

Tompkins, Adrian M; Ermert, Volker

2013-02-18

The relative roles of climate variability and population related effects in malaria transmission could be better understood if regional-scale dynamical malaria models could account for these factors. A new dynamical community malaria model is introduced that accounts for the temperature and rainfall influences on the parasite and vector life cycles which are finely resolved in order to correctly represent the delay between the rains and the malaria season. The rainfall drives a simple but physically based representation of the surface hydrology. The model accounts for the population density in the calculation of daily biting rates. Model simulations of entomological inoculation rate and circumsporozoite protein rate compare well to data from field studies from a wide range of locations in West Africa that encompass both seasonal endemic and epidemic fringe areas. A focus on Bobo-Dioulasso shows the ability of the model to represent the differences in transmission rates between rural and peri-urban areas in addition to the seasonality of malaria. Fine spatial resolution regional integrations for Eastern Africa reproduce the malaria atlas project (MAP) spatial distribution of the parasite ratio, and integrations for West and Eastern Africa show that the model grossly reproduces the reduction in parasite ratio as a function of population density observed in a large number of field surveys, although it underestimates malaria prevalence at high densities probably due to the neglect of population migration. A new dynamical community malaria model is publicly available that accounts for climate and population density to simulate malaria transmission on a regional scale. The model structure facilitates future development to incorporate migration, immunity and interventions.

A regional-scale, high resolution dynamical malaria model that accounts for population density, climate and surface hydrology

PubMed Central

2013-01-01

Background The relative roles of climate variability and population related effects in malaria transmission could be better understood if regional-scale dynamical malaria models could account for these factors. Methods A new dynamical community malaria model is introduced that accounts for the temperature and rainfall influences on the parasite and vector life cycles which are finely resolved in order to correctly represent the delay between the rains and the malaria season. The rainfall drives a simple but physically based representation of the surface hydrology. The model accounts for the population density in the calculation of daily biting rates. Results Model simulations of entomological inoculation rate and circumsporozoite protein rate compare well to data from field studies from a wide range of locations in West Africa that encompass both seasonal endemic and epidemic fringe areas. A focus on Bobo-Dioulasso shows the ability of the model to represent the differences in transmission rates between rural and peri-urban areas in addition to the seasonality of malaria. Fine spatial resolution regional integrations for Eastern Africa reproduce the malaria atlas project (MAP) spatial distribution of the parasite ratio, and integrations for West and Eastern Africa show that the model grossly reproduces the reduction in parasite ratio as a function of population density observed in a large number of field surveys, although it underestimates malaria prevalence at high densities probably due to the neglect of population migration. Conclusions A new dynamical community malaria model is publicly available that accounts for climate and population density to simulate malaria transmission on a regional scale. The model structure facilitates future development to incorporate migration, immunity and interventions. PMID:23419192

Modelling the effect of urbanization on the transmission of an infectious disease.

PubMed

Zhang, Ping; Atkinson, Peter M

2008-01-01

This paper models the impact of urbanization on infectious disease transmission by integrating a CA land use development model, population projection matrix model and CA epidemic model in S-Plus. The innovative feature of this model lies in both its explicit treatment of spatial land use development, demographic changes, infectious disease transmission and their combination in a dynamic, stochastic model. Heuristically-defined transition rules in cellular automata (CA) were used to capture the processes of both land use development with urban sprawl and infectious disease transmission. A population surface model and dwelling distribution surface were used to bridge the gap between urbanization and infectious disease transmission. A case study is presented involving modelling influenza transmission in Southampton, a dynamically evolving city in the UK. The simulation results for Southampton over a 30-year period show that the pattern of the average number of infection cases per day can depend on land use and demographic changes. The modelling framework presents a useful tool that may be of use in planning applications.

Simulating the Interactions Among Land Use, Transportation, and Economy to Inform Light Rail Transit Decisions

EPA Science Inventory

In most transportation studies, computer models that forecast travel behavior statistics for a future year use static projections of the spatial distribution of future population and employment growth as inputs. As a result, they are unable to account for the temporally dynamic a...

Simulating the Interactions Among Land Use, Transportation, and Economy to Inform Light Rail Transit Decisions (proceedings)

EPA Science Inventory

In most transportation studies, computer models that forecast travel behavior statistics for a future year use static projections of the spatial distribution of future population and employment growth as inputs. As a result, they are unable to account for the temporally dynamic a...

A GIS-BASED WETLAND ASESSMENT MODEL FOR PREDICTING AVIAN HABITAT SUITABILITY UNDER UNCERTAINTY

EPA Science Inventory

The Farmington Bay region of the Great Salt Lake is fringed with an array of wetland complexes providing critical avian habitat. Land use and hydrological changes resulting from projected urban population increases and combined with the low topographical relief of the lake basin...

78 FR 16509 - Amendment to Information Collection Activity; Comment Request

Federal Register 2010, 2011, 2012, 2013, 2014

2013-03-15

... the labor market and achieve self-sufficiency. The projects will evaluate up to twelve subsidized and... assist ex-offenders and noncustodial parents improve labor market outcomes, reduce criminal recidivism... related program models and target populations. Thus, ACF and ETA have agreed to collaborate on the design...

Using population viability analysis to predict the effects of climate change on the extinction risk of an endangered limestone endemic shrub, Arizona cliffrose.

PubMed

Maschinski, Joyce; Baggs, Joanne E; Quintana-Ascencio, Pedro F; Menges, Eric S

2006-02-01

The threat of global warming to rare species is a growing concern, yet few studies have predicted its effects on rare populations. Using demographic data gathered in both drought and nondrought years between 1996-2003 in central Arizona upper Sonoran Desert, we modeled population viability for the federally endangered Purshia subintegra (Kearney) Henrickson (Arizona cliffrose). We used deterministic matrix projection models and stochastic models simulating weather conditions during our study, given historical weather variation and under scenarios of increased aridity. Our models suggest that the P. subintegra population in Verde Valley is slowly declining and will be at greater risk of extinction with increased aridity. Across patches at a fine spatial scale, demographic performance was associated with environmental factors. Moist sites (patches with the highest soil moisture, lowest sand content, and most northern aspects) had the highest densities, highest seedling recruitment, and highest risk of extinction over the shortest time span. Extinction risk in moist sites was exacerbated by higher variance in recruitment and mortality. Dry sites had higher cumulative adult survival and lower extinction risk but negative growth rates. Steps necessary for the conservation of the species include introductions at more northern latitudes and in situ manipulations to enhance seedling recruitment and plant survival. We demonstrate that fine spatial-scale modeling is necessary to predict where patches with highest extinction risk or potential refugia for rare species may occur Because current climate projections for the 21st century imply range shifts at rates of 300 to 500 km/century, which are beyond even exceptional examples of shifts in the fossil record of 100-150 km, it is likely that preservation of many rare species will require human intervention and a long-term commitment. Global warming conditions are likely to reduce the carrying capacity of many rare species' habitats.

Forecast of the number of patients with end-stage renal disease in the United States to the year 2010.

PubMed

Xue, J L; Ma, J Z; Louis, T A; Collins, A J

2001-12-01

As the United States end-stage renal disease (ESRD) program enters the new millennium, the continued growth of the ESRD population poses a challenge for policy makers, health care providers, and financial planners. To assist in future planning for the ESRD program, the growth of patient numbers and Medicare costs was forecasted to the year 2010 by modeling of historical data from 1982 through 1997. A stepwise autoregressive method and exponential smoothing models were used. The forecasting models for ESRD patient numbers demonstrated mean errors of -0.03 to 1.03%, relative to the observed values. The model for Medicare payments demonstrated -0.12% mean error. The R(2) values for the forecasting models ranged from 99.09 to 99.98%. On the basis of trends in patient numbers, this forecast projects average annual growth of the ESRD populations of approximately 4.1% for new patients, 6.4% for long-term ESRD patients, 7.1% for dialysis patients, 6.1% for patients with functioning transplants, and 8.2% for patients on waiting lists for transplants, as well as 7.7% for Medicare expenditures. The numbers of patients with ESRD in 2010 are forecasted to be 129,200 +/- 7742 (95% confidence limits) new patients, 651,330 +/- 15,874 long-term ESRD patients, 520,240 +/- 25,609 dialysis patients, 178,806 +/- 4349 patients with functioning transplants, and 95,550 +/- 5478 patients on waiting lists. The forecasted Medicare expenditures are projected to increase to $28.3 +/- 1.7 billion by 2010. These projections are subject to many factors that may alter the actual growth, compared with the historical patterns. They do, however, provide a basis for discussing the future growth of the ESRD program and how the ESRD community can meet the challenges ahead.