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Sample records for long-term stochastic population

  1. Stochastic Induction of Long-Term Potentiation and Long-Term Depression.

    PubMed

    Antunes, G; Roque, A C; Simoes-de-Souza, F M

    2016-01-01

    Long-term depression (LTD) and long-term potentiation (LTP) of granule-Purkinje cell synapses are persistent synaptic alterations induced by high and low rises of the intracellular calcium ion concentration ([Ca(2+)]), respectively. The occurrence of LTD involves the activation of a positive feedback loop formed by protein kinase C, phospholipase A2, and the extracellular signal-regulated protein kinase pathway, and its expression comprises the reduction of the population of synaptic AMPA receptors. Recently, a stochastic computational model of these signalling processes demonstrated that, in single synapses, LTD is probabilistic and bistable. Here, we expanded this model to simulate LTP, which requires protein phosphatases and the increase in the population of synaptic AMPA receptors. Our results indicated that, in single synapses, while LTD is bistable, LTP is gradual. Ca(2+) induced both processes stochastically. The magnitudes of the Ca(2+) signals and the states of the signalling network regulated the likelihood of LTP and LTD and defined dynamic macroscopic Ca(2+) thresholds for the synaptic modifications in populations of synapses according to an inverse Bienenstock, Cooper and Munro (BCM) rule or a sigmoidal function. In conclusion, our model presents a unifying mechanism that explains the macroscopic properties of LTP and LTD from their dynamics in single synapses. PMID:27485552

  2. Stochastic Induction of Long-Term Potentiation and Long-Term Depression

    PubMed Central

    Antunes, G.; Roque, A. C.; Simoes-de-Souza, F. M.

    2016-01-01

    Long-term depression (LTD) and long-term potentiation (LTP) of granule-Purkinje cell synapses are persistent synaptic alterations induced by high and low rises of the intracellular calcium ion concentration ([Ca2+]), respectively. The occurrence of LTD involves the activation of a positive feedback loop formed by protein kinase C, phospholipase A2, and the extracellular signal-regulated protein kinase pathway, and its expression comprises the reduction of the population of synaptic AMPA receptors. Recently, a stochastic computational model of these signalling processes demonstrated that, in single synapses, LTD is probabilistic and bistable. Here, we expanded this model to simulate LTP, which requires protein phosphatases and the increase in the population of synaptic AMPA receptors. Our results indicated that, in single synapses, while LTD is bistable, LTP is gradual. Ca2+ induced both processes stochastically. The magnitudes of the Ca2+ signals and the states of the signalling network regulated the likelihood of LTP and LTD and defined dynamic macroscopic Ca2+ thresholds for the synaptic modifications in populations of synapses according to an inverse Bienenstock, Cooper and Munro (BCM) rule or a sigmoidal function. In conclusion, our model presents a unifying mechanism that explains the macroscopic properties of LTP and LTD from their dynamics in single synapses. PMID:27485552

  3. Long-term dynamics of Typha populations

    USGS Publications Warehouse

    Grace, J.B.; Wetzel, R.G.

    1998-01-01

    The zonation of Typha populations in an experimental pond in Michigan was re-examined 15 years after the original sampling to gain insight into the long-term dynamics. Current distributions of Typha populations were also examined in additional experimental ponds at the site that have been maintained for 23 years. The zonation between T. latifolia and T. angustifolia in the previously studied pond 15 years after the initial sampling revealed that the density and distribution of shoots had not changed significantly. Thus, it appears that previously reported results (based on 7- year old populations) have remained consistent over time. Additional insight into the interaction between these two taxa was sought by comparing mixed and monoculture stands in five experimental ponds that have remained undisturbed for their 23-year history. The maximum depth of T. latifolia, the shallow- water species, was not significantly reduced when growing in the presence of the more flood tolerant T. angustifolia. In contrast, the minimum depth of T. angustifolia was reduced from 0 to 37 cm when in the presence of T. latifolia. When total populations were compared between monoculture and mixed stands, the average density of T. angustifolia shoots was 59.4 percent lower in mixed stands while the density of T. latifolia was 32 percent lower, with T. angustifolia most affected at shallow depths (reduced by 92 percent) and T. latifolia most affected at the deepest depths (reduced by 60 percent). These long-term observations indicate that competitive displacement between Typha taxa has remained stable over time.

  4. A scalable computational framework for establishing long-term behavior of stochastic reaction networks.

    PubMed

    Gupta, Ankit; Briat, Corentin; Khammash, Mustafa

    2014-06-01

    Reaction networks are systems in which the populations of a finite number of species evolve through predefined interactions. Such networks are found as modeling tools in many biological disciplines such as biochemistry, ecology, epidemiology, immunology, systems biology and synthetic biology. It is now well-established that, for small population sizes, stochastic models for biochemical reaction networks are necessary to capture randomness in the interactions. The tools for analyzing such models, however, still lag far behind their deterministic counterparts. In this paper, we bridge this gap by developing a constructive framework for examining the long-term behavior and stability properties of the reaction dynamics in a stochastic setting. In particular, we address the problems of determining ergodicity of the reaction dynamics, which is analogous to having a globally attracting fixed point for deterministic dynamics. We also examine when the statistical moments of the underlying process remain bounded with time and when they converge to their steady state values. The framework we develop relies on a blend of ideas from probability theory, linear algebra and optimization theory. We demonstrate that the stability properties of a wide class of biological networks can be assessed from our sufficient theoretical conditions that can be recast as efficient and scalable linear programs, well-known for their tractability. It is notably shown that the computational complexity is often linear in the number of species. We illustrate the validity, the efficiency and the wide applicability of our results on several reaction networks arising in biochemistry, systems biology, epidemiology and ecology. The biological implications of the results as well as an example of a non-ergodic biological network are also discussed. PMID:24968191

  5. A Scalable Computational Framework for Establishing Long-Term Behavior of Stochastic Reaction Networks

    PubMed Central

    Khammash, Mustafa

    2014-01-01

    Reaction networks are systems in which the populations of a finite number of species evolve through predefined interactions. Such networks are found as modeling tools in many biological disciplines such as biochemistry, ecology, epidemiology, immunology, systems biology and synthetic biology. It is now well-established that, for small population sizes, stochastic models for biochemical reaction networks are necessary to capture randomness in the interactions. The tools for analyzing such models, however, still lag far behind their deterministic counterparts. In this paper, we bridge this gap by developing a constructive framework for examining the long-term behavior and stability properties of the reaction dynamics in a stochastic setting. In particular, we address the problems of determining ergodicity of the reaction dynamics, which is analogous to having a globally attracting fixed point for deterministic dynamics. We also examine when the statistical moments of the underlying process remain bounded with time and when they converge to their steady state values. The framework we develop relies on a blend of ideas from probability theory, linear algebra and optimization theory. We demonstrate that the stability properties of a wide class of biological networks can be assessed from our sufficient theoretical conditions that can be recast as efficient and scalable linear programs, well-known for their tractability. It is notably shown that the computational complexity is often linear in the number of species. We illustrate the validity, the efficiency and the wide applicability of our results on several reaction networks arising in biochemistry, systems biology, epidemiology and ecology. The biological implications of the results as well as an example of a non-ergodic biological network are also discussed. PMID:24968191

  6. 3D printed cellular solid outperforms traditional stochastic foam in long-term mechanical response.

    PubMed

    Maiti, A; Small, W; Lewicki, J P; Weisgraber, T H; Duoss, E B; Chinn, S C; Pearson, M A; Spadaccini, C M; Maxwell, R S; Wilson, T S

    2016-01-01

    3D printing of polymeric foams by direct-ink-write is a recent technological breakthrough that enables the creation of versatile compressible solids with programmable microstructure, customizable shapes, and tunable mechanical response including negative elastic modulus. However, in many applications the success of these 3D printed materials as a viable replacement for traditional stochastic foams critically depends on their mechanical performance and micro-architectural stability while deployed under long-term mechanical strain. To predict the long-term performance of the two types of foams we employed multi-year-long accelerated aging studies under compressive strain followed by a time-temperature-superposition analysis using a minimum-arc-length-based algorithm. The resulting master curves predict superior long-term performance of the 3D printed foam in terms of two different metrics, i.e., compression set and load retention. To gain deeper understanding, we imaged the microstructure of both foams using X-ray computed tomography, and performed finite-element analysis of the mechanical response within these microstructures. This indicates a wider stress variation in the stochastic foam with points of more extreme local stress as compared to the 3D printed material, which might explain the latter's improved long-term stability and mechanical performance.

  7. 3D printed cellular solid outperforms traditional stochastic foam in long-term mechanical response

    PubMed Central

    Maiti, A.; Small, W.; Lewicki, J. P.; Weisgraber, T. H.; Duoss, E. B.; Chinn, S. C.; Pearson, M. A.; Spadaccini, C. M.; Maxwell, R. S.; Wilson, T. S.

    2016-01-01

    3D printing of polymeric foams by direct-ink-write is a recent technological breakthrough that enables the creation of versatile compressible solids with programmable microstructure, customizable shapes, and tunable mechanical response including negative elastic modulus. However, in many applications the success of these 3D printed materials as a viable replacement for traditional stochastic foams critically depends on their mechanical performance and micro-architectural stability while deployed under long-term mechanical strain. To predict the long-term performance of the two types of foams we employed multi-year-long accelerated aging studies under compressive strain followed by a time-temperature-superposition analysis using a minimum-arc-length-based algorithm. The resulting master curves predict superior long-term performance of the 3D printed foam in terms of two different metrics, i.e., compression set and load retention. To gain deeper understanding, we imaged the microstructure of both foams using X-ray computed tomography, and performed finite-element analysis of the mechanical response within these microstructures. This indicates a wider stress variation in the stochastic foam with points of more extreme local stress as compared to the 3D printed material, which might explain the latter’s improved long-term stability and mechanical performance. PMID:27117858

  8. 3D printed cellular solid outperforms traditional stochastic foam in long-term mechanical response

    DOE PAGES

    Maiti, A.; Small, W.; Lewicki, J.; Weisgraber, T. H.; Duoss, E. B.; Chinn, S. C.; Pearson, M. A.; Spadaccini, C. M.; Maxwell, R. S.; Wilson, T. S.

    2016-04-27

    3D printing of polymeric foams by direct-ink-write is a recent technological breakthrough that enables the creation of versatile compressible solids with programmable microstructure, customizable shapes, and tunable mechanical response including negative elastic modulus. However, in many applications the success of these 3D printed materials as a viable replacement for traditional stochastic foams critically depends on their mechanical performance and micro-architectural stability while deployed under long-term mechanical strain. To predict the long-term performance of the two types of foams we employed multi-year-long accelerated aging studies under compressive strain followed by a time-temperature-superposition analysis using a minimum-arc-length-based algorithm. The resulting master curvesmore » predict superior long-term performance of the 3D printed foam in terms of two different metrics, i.e., compression set and load retention. To gain deeper understanding, we imaged the microstructure of both foams using X-ray computed tomography, and performed finite-element analysis of the mechanical response within these microstructures. As a result, this indicates a wider stress variation in the stochastic foam with points of more extreme local stress as compared to the 3D printed material, which might explain the latter’s improved long-term stability and mechanical performance.« less

  9. 3D printed cellular solid outperforms traditional stochastic foam in long-term mechanical response

    NASA Astrophysics Data System (ADS)

    Maiti, A.; Small, W.; Lewicki, J. P.; Weisgraber, T. H.; Duoss, E. B.; Chinn, S. C.; Pearson, M. A.; Spadaccini, C. M.; Maxwell, R. S.; Wilson, T. S.

    2016-04-01

    3D printing of polymeric foams by direct-ink-write is a recent technological breakthrough that enables the creation of versatile compressible solids with programmable microstructure, customizable shapes, and tunable mechanical response including negative elastic modulus. However, in many applications the success of these 3D printed materials as a viable replacement for traditional stochastic foams critically depends on their mechanical performance and micro-architectural stability while deployed under long-term mechanical strain. To predict the long-term performance of the two types of foams we employed multi-year-long accelerated aging studies under compressive strain followed by a time-temperature-superposition analysis using a minimum-arc-length-based algorithm. The resulting master curves predict superior long-term performance of the 3D printed foam in terms of two different metrics, i.e., compression set and load retention. To gain deeper understanding, we imaged the microstructure of both foams using X-ray computed tomography, and performed finite-element analysis of the mechanical response within these microstructures. This indicates a wider stress variation in the stochastic foam with points of more extreme local stress as compared to the 3D printed material, which might explain the latter’s improved long-term stability and mechanical performance.

  10. Sensitivity of train stochastic dynamics to long-term evolution of track irregularities

    NASA Astrophysics Data System (ADS)

    Lestoille, N.; Soize, C.; Funfschilling, C.

    2016-05-01

    The influence of the track geometry on the dynamic response of the train is of great concern for the railway companies, because they have to guarantee the safety of the train passengers in ensuring the stability of the train. In this paper, the long-term evolution of the dynamic response of the train on a stretch of the railway track is studied with respect to the long-term evolution of the track geometry. The characterisation of the long-term evolution of the train response allows the railway companies to start off maintenance operations of the track at the best moment. The study is performed using measurements of the track geometry, which are carried out very regularly by a measuring train. A stochastic model of the studied stretch of track is created in order to take into account the measurement uncertainties in the track geometry. The dynamic response of the train is simulated with a multibody software. A noise is added in output of the simulation to consider the uncertainties in the computational model of the train dynamics. Indicators on the dynamic response of the train are defined, allowing to visualize the long-term evolution of the stability and the comfort of the train, when the track geometry deteriorates.

  11. Disturbance frequency and vertical distribution of seeds affect long-term population dynamics: a mechanistic seed bank model.

    PubMed

    Eager, Eric Alan; Haridas, Chirakkal V; Pilson, Diana; Rebarber, Richard; Tenhumberg, Brigitte

    2013-08-01

    Seed banks are critically important for disturbance specialist plants because seeds of these species germinate only in disturbed soil. Disturbance and seed depth affect the survival and germination probability of seeds in the seed bank, which in turn affect population dynamics. We develop a density-dependent stochastic integral projection model to evaluate the effect of stochastic soil disturbances on plant population dynamics with an emphasis on mimicking how disturbances vertically redistribute seeds within the seed bank. We perform a simulation analysis of the effect of the frequency and mean depth of disturbances on the population's quasi-extinction probability, as well as the long-term mean and variance of the total density of seeds in the seed bank. We show that increasing the frequency of disturbances increases the long-term viability of the population, but the relationship between the mean depth of disturbance and the long-term viability of the population are not necessarily monotonic for all parameter combinations. Specifically, an increase in the probability of disturbance increases the long-term viability of the total seed bank population. However, if the probability of disturbance is too low, a shallower mean depth of disturbance can increase long-term viability, a relationship that switches as the probability of disturbance increases. However, a shallow disturbance depth is beneficial only in scenarios with low survival in the seed bank.

  12. The importance of stochastic signaling processes in the induction of long-term synaptic plasticity.

    PubMed

    De Schutter, Erik

    2013-11-01

    A stochastic model of the signaling network responsible for the induction of long-term depression (LTD) at the parallel fiber to Purkinje cell synapse is described. The model includes a PKC-ERK-cPLA2 positive feedback loop and mechanisms of AMPA receptor trafficking. It was tuned to replicate calcium uncaging experiments that cause LTD. The ultrasensitive activation of ERK makes the signaling network activity bistable, causing either LTD or not. Therefore, in single synapses only two discrete stable states (LTD and non-LTD) can be expressed. The stochastic properties of the signaling network causes threshold dithering and probabilistic expression of LTD, which allows at the macroscopic level for many different and stable mean magnitudes of depression. When the volume of a single spine is simulated no thresholds for the calcium input signal are present. Such thresholds appear only when the volume of simulation is increased by a factor 100 or more and the model output is then bistable. Similarly, deterministic solutions of the same model show only bistable behavior. LTD induction requires activation of the PKC-ERK-cPLA2 positive feedback loop but this activity is not constant: the activities of ERK and of cPLA2 fluctuate strongly. This is much less the case for PKC which is more constantly activated and thereby promotes a stable output of the pathway. PMID:23267752

  13. Long-term projections of national, regional, and state population

    SciTech Connect

    McDonald, J.F.; South, D.W.

    1986-07-01

    The projections prepared by the US Bureau of the Census are the best available projections of total US population. The DRI projections of population at the regional and state level to the year 2008 are the best available and are consistent with the US Bureau of the Census projections of total US population. The DRI regional and state projections can be extended from 2008 to 2030 with a simple model based on economic opportunity, although an even simpler model - constant shares - is used for the 1985 test runs. The US Bureau of the Census prepares the best available projections of the US age-sex distribution.

  14. Are Changes in the Mean or Variability of Climate Signals More Important for Long-Term Stochastic Growth Rate?

    PubMed Central

    García-Carreras, Bernardo; Reuman, Daniel C.

    2013-01-01

    Population dynamics are affected by changes in both the mean and standard deviation of climate, e.g., changes in average temperature are likely to affect populations, but so are changes in the strength of year-to-year temperature variability. The impacts of increases in average temperature are extensively researched, while the impacts of changes in climate variability are less studied. Is the greater attention given to changes in mean environment justified? To help answer this question we developed a simple population model, explicitly linked to an environmental process. We used the model to compare the sensitivities of a population's long-term stochastic growth rate, a measure of fitness, to changes in the mean and standard deviation of the environment. Results are interpreted in light of a comparative analysis of the relative magnitudes of change in means and standard deviations of biologically relevant climate variables in the United States. Results show that changes in the variability of the environment can be more important for many populations. Changes in mean conditions are likely to have a greater impact than changes in variability on populations far from their ideal environment, for example, populations near species range boundaries and potentially of conservation concern. Populations near range centres and close to their ideal environment are more likely to be affected by changes in variability. Among pest and insect disease vectors, as well as species of commercial value, populations likely to be of greatest economic and public health significance are those near species range centers, living in a near-ideal environment for the species. Observed changes in the variability of climate variables may benefit these populations. PMID:23691131

  15. Long-term dynamics of adaptation in asexual populations.

    PubMed

    Wiser, Michael J; Ribeck, Noah; Lenski, Richard E

    2013-12-13

    Experimental studies of evolution have increased greatly in number in recent years, stimulated by the growing power of genomic tools. However, organismal fitness remains the ultimate metric for interpreting these experiments, and the dynamics of fitness remain poorly understood over long time scales. Here, we examine fitness trajectories for 12 Escherichia coli populations during 50,000 generations. Mean fitness appears to increase without bound, consistent with a power law. We also derive this power-law relation theoretically by incorporating clonal interference and diminishing-returns epistasis into a dynamical model of changes in mean fitness over time.

  16. Long-term care of the aging population with intellectual and developmental disabilities.

    PubMed

    Kim, Nae-Hwa; Hoyek, Georges El; Chau, Diane

    2011-05-01

    The aging population with intellectual and developmental disabilities (I/DD) deserves appropriate health care and social support. This population poses unique medical and social challenges to the multidisciplinary team that provides care. In the past, long-term care (LTC) facilities played an essential role in the livelihood of this population. The likelihood that the geriatric LTC system must prepare for adequately caring for this population is high. This article conveys the need to prepare for the inclusion of the growing aging population with I/DD into long-term care with the general elderly population in the near future.

  17. Long-term effective population size dynamics of an intensively monitored vertebrate population.

    PubMed

    Mueller, A-K; Chakarov, N; Krüger, O; Hoffman, J I

    2016-10-01

    Long-term genetic data from intensively monitored natural populations are important for understanding how effective population sizes (Ne) can vary over time. We therefore genotyped 1622 common buzzard (Buteo buteo) chicks sampled over 12 consecutive years (2002-2013 inclusive) at 15 microsatellite loci. This data set allowed us to both compare single-sample with temporal approaches and explore temporal patterns in the effective number of parents that produced each cohort in relation to the observed population dynamics. We found reasonable consistency between linkage disequilibrium-based single-sample and temporal estimators, particularly during the latter half of the study, but no clear relationship between annual Ne estimates () and census sizes. We also documented a 14-fold increase in between 2008 and 2011, a period during which the census size doubled, probably reflecting a combination of higher adult survival and immigration from further afield. Our study thus reveals appreciable temporal heterogeneity in the effective population size of a natural vertebrate population, confirms the need for long-term studies and cautions against drawing conclusions from a single sample. PMID:27553455

  18. Long-term growth of desert tortoises (Gopherus agassizii) in a southern Nevada population

    USGS Publications Warehouse

    Medica, Philip A.; Nussear, Kenneth E.; Esque, Todd C.; Saethre, Mary B.

    2012-01-01

    Knowledge of growth rates, age at maturity, and longevity are important aspects of a species life history and are directly applicable to life table creation and population viability analyses. We measured the growth of a cohort of 17 semi-wild Desert Tortoises (Gopherus agassizii) located in Rock Valley, Nevada over a 47-yr period beginning in 1963. The tortoises were initially marked as hatchling and juvenile animals between the years 1963 and 1965 and ranged in size from 47 to 77 mm in plastron length. We assigned ages of 1--4 yr to the tortoises at initial capture based on their body size. These tortoises were recaptured, measured, and weighed approximately annually since their initial capture. Growth of male and female tortoises did not differ significantly until animals reached the age of 23--25 yr. Annual tortoise growth was correlated with the production of ephemeral vegetation, while accounting for size, sex, and repeated measurements of the animals as well as the interval between measurements. However, the production of ephemeral plants was likewise highly correlated (non-linearly) with winter rainfall. Stochastic predation events between 2003 and 2007 decimated this cohort of tortoises. The average age of the long-term surviving tortoises from this cohort was 43 yr with a range of 39--47 yr. Twelve of the tortoises survived to the age of 39 yr and 11 of the 12 reached 40 yr.

  19. Long-term growth of Desert Tortoises (Gopherus agassizii) in a southern Nevada population

    USGS Publications Warehouse

    Medica, P.A.; Nussear, Kenneth E.; Esque, Todd C.; Saethre, Mary B.

    2012-01-01

    Knowledge of growth rates, age at maturity, and longevity are important aspects of a species life history and are directly applicable to life table creation and population viability analyses. We measured the growth of a cohort of 17 semi-wild Desert Tortoises (Gopherus agassizii) located in Rock Valley, Nevada over a 47-yr period beginning in 1963. The tortoises were initially marked as hatchling and juvenile animals between the years 1963 and 1965 and ranged in size from 47 to 77 mm in plastron length. We assigned ages of 1-4 yr to the tortoises at initial capture based on their body size. These tortoises were recaptured, measured, and weighed approximately annually since their initial capture. Growth of male and female tortoises did not differ significantly until animals reached the age of 23-25 yr. Annual tortoise growth was correlated with the production of ephemeral vegetation, while accounting for size, sex, and repeated measurements of the animals as well as the interval between measurements. However, the production of ephemeral plants was likewise highly correlated (non-linearly) with winter rainfall. Stochastic predation events between 2003 and 2007 decimated this cohort of tortoises. The average age of the long-term surviving tortoises from this cohort was 43 yr with a range of 39-47 yr. Twelve of the tortoises survived to the age of 39 yr and 11 of the 12 reached 40 yr.

  20. Deterministic processes guide long-term synchronised population dynamics in replicate anaerobic digesters

    PubMed Central

    Vanwonterghem, Inka; Jensen, Paul D; Dennis, Paul G; Hugenholtz, Philip; Rabaey, Korneel; Tyson, Gene W

    2014-01-01

    A replicate long-term experiment was conducted using anaerobic digestion (AD) as a model process to determine the relative role of niche and neutral theory on microbial community assembly, and to link community dynamics to system performance. AD is performed by a complex network of microorganisms and process stability relies entirely on the synergistic interactions between populations belonging to different functional guilds. In this study, three independent replicate anaerobic digesters were seeded with the same diverse inoculum, supplied with a model substrate, α-cellulose, and operated for 362 days at a 10-day hydraulic residence time under mesophilic conditions. Selective pressure imposed by the operational conditions and model substrate caused large reproducible changes in community composition including an overall decrease in richness in the first month of operation, followed by synchronised population dynamics that correlated with changes in reactor performance. This included the synchronised emergence and decline of distinct Ruminococcus phylotypes at day 148, and emergence of a Clostridium and Methanosaeta phylotype at day 178, when performance became stable in all reactors. These data suggest that many dynamic functional niches are predictably filled by phylogenetically coherent populations over long time scales. Neutral theory would predict that a complex community with a high degree of recognised functional redundancy would lead to stochastic changes in populations and community divergence over time. We conclude that deterministic processes may play a larger role in microbial community dynamics than currently appreciated, and under controlled conditions it may be possible to reliably predict community structural and functional changes over time. PMID:24739627

  1. Analysis of Quantitative Traits in Two Long-Term Randomly Mated Soybean Populations I. Genetic Variances

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The genetic effects of long term random mating and natural selection aided by genetic male sterility were evaluated in two soybean [Glycine max (L.) Merr.] populations: RSII and RSIII. Population means, variances, and heritabilities were estimated to determine the effects of 26 generations of random...

  2. Genetic and phenotypic correlations of quantitative traits in two long-term randomly mated soybean populations

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The genetic effects of long term random mating and natural selection aided by genetic male sterility (gms) were evaluated in two soybean [Glycine max (L.) Merr.] populations designated: RSII and RSIII. These populations were evaluated in the field at three locations each with two replications. Genot...

  3. Gauging the Purported Costs of Public Data Archiving for Long-Term Population Studies

    PubMed Central

    Evans, Simon Robin

    2016-01-01

    It was recently proposed that long-term population studies be exempted from the expectation that authors publicly archive the primary data underlying published articles. Such studies are valuable to many areas of ecological and evolutionary biological research, and multiple risks to their viability were anticipated as a result of public data archiving (PDA), ultimately all stemming from independent reuse of archived data. However, empirical assessment was missing, making it difficult to determine whether such fears are realistic. I addressed this by surveying data packages from long-term population studies archived in the Dryad Digital Repository. I found no evidence that PDA results in reuse of data by independent parties, suggesting the purported costs of PDA for long-term population studies have been overstated. PMID:27058254

  4. Long-term prescribing of antidepressants in the older population: a qualitative study

    PubMed Central

    Dickinson, Rebecca; Knapp, Peter; House, Allan O; Dimri, Vandana; Zermansky, Arnold; Petty, Duncan; Holmes, John; Raynor, David K

    2010-01-01

    Background High rates of long-term antidepressant prescribing have been identified in the older population. Aims To explore the attitudes of older patients and their GPs to taking long-term antidepressant therapy, and their accounts of the influences on long-term antidepressant use. Design of study Qualitative study using in-depth semi-structured interviews. Setting One primary care trust in North Bradford. Method Thirty-six patients aged ≥75 years and 10 GPs were interviewed. Patients were sampled to ensure diversity in age, sex, antidepressant type, and home circumstances. Results Participants perceived significant benefits and expressed little apprehension about taking long-term antidepressants, despite being aware of the psychological and social factors involved in onset and persistence of depression. Barriers to discontinuation were identified following four themes: pessimism about the course and curability of depression; negative expectations and experiences of ageing; medicine discontinuation perceived by patients as a threat to stability; and passive (therapeutic momentum) and active (therapeutic maintenance) decisions to accept the continuing need for medication. Conclusion There is concern at a public health level about high rates of long-term antidepressant prescribing, but no evidence was found of a drive for change either from the patients or the doctors interviewed. Any apprehension was more than balanced by attitudes and behaviours supporting continuation. These findings will need to be incorporated into the planning of interventions aimed at reducing long-term antidepressant prescribing in older people. PMID:20353660

  5. Long-term metapopulation study of the Glanville fritillary butterfly (Melitaea cinxia): survey methods, data management, and long-term population trends

    PubMed Central

    Ojanen, Sami P; Nieminen, Marko; Meyke, Evgeniy; Pöyry, Juha; Hanski, Ilkka

    2013-01-01

    Long-term observational studies conducted at large (regional) spatial scales contribute to better understanding of landscape effects on population and evolutionary dynamics, including the conditions that affect long-term viability of species, but large-scale studies are expensive and logistically challenging to keep running for a long time. Here, we describe the long-term metapopulation study of the Glanville fritillary butterfly (Melitaea cinxia) that has been conducted since 1991 in a large network of 4000 habitat patches (dry meadows) within a study area of 50 by 70 km in the Åland Islands in Finland. We explain how the landscape structure has been described, including definition, delimitation, and mapping of the habitat patches; methods of field survey, including the logistics, cost, and reliability of the survey; and data management using the EarthCape biodiversity platform. We describe the long-term metapopulation dynamics of the Glanville fritillary based on the survey. There has been no long-term change in the overall size of the metapopulation, but the level of spatial synchrony and hence the amplitude of fluctuations in year-to-year metapopulation dynamics have increased over the years, possibly due to increasing frequency of exceptional weather conditions. We discuss the added value of large-scale and long-term population studies, but also emphasize the need to integrate more targeted experimental studies in the context of long-term observational studies. For instance, in the case of the Glanville fritillary project, the long-term study has produced an opportunity to sample individuals for experiments from local populations with a known demographic history. These studies have demonstrated striking differences in dispersal rate and other life-history traits of individuals from newly established local populations (the offspring of colonizers) versus individuals from old, established local populations. The long-term observational study has stimulated the

  6. Declining scaup populations: A retrospective analysis of long-term population and harvest survey data

    USGS Publications Warehouse

    Afton, A.D.; Anderson, M.G.

    2001-01-01

    We examined long-term databases concerning population status of scaup (lesser [Aythya affinis] and greater scaup [A. marila] combined) and harvest statistics of lesser scaup to identify factors potentially limiting population growth. Specifically, we explored evidence for and against the general hypotheses that scaup populations have declined in association with declining recruitment and/or female survival. We examined geographic heterogeneity in scaup demographic patterns that could yield evidence about potential limiting factors. Several biases exist in survey methodology used to estimate scaup populations and harvest statistics; however, none of these biases likely accounted for our major findings that (1) the continental scaup breeding population has declined over the last 20 years, with widespread and consistent declines within surveyed areas of the Canadian western boreal forest where most lesser scaup breed; (2) sex ratios of lesser scaup in the U.S. harvest have increased (more males now relative to females); and (3) age ratios of lesser scaup in the U.S. harvest have declined (fewer immatures now relative to adults), especially in the midcontinent region. We interpreted these major findings as evidence that (1) recruitment of lesser scaup has declined over the last 20 years, particularly in the Canadian western boreal forest; and (2) survival of female lesser scaup has declined relative to that of males. We found little evidence that harvest was associated with the scaup population decline. Our findings underscore the need for both improvements and changes to population survey procedures and new research to discriminate among various hypotheses explaining the recent scaup population decline.

  7. Development of a Compound Distribution Markov Chain Model for Stochastic Generation of Rainfall with Long Term Persistence

    NASA Astrophysics Data System (ADS)

    Kamal Chowdhury, AFM; Lockart, Natalie; Willgoose, Garry; Kuczera, George

    2015-04-01

    One of the overriding issues in the rainfall simulation is the underestimation of observed rainfall variability in longer timescales (e.g. monthly, annual and multi-year), which usually results into under-estimation of reservoir reliability in urban water planning. This study has developed a Compound Distribution Markov Chain (CDMC) model for stochastic generation of daily rainfall. We used two parameters of Markov Chain process (transition probabilities of wet-to-wet and dry-to-dry days) for simulating rainfall occurrence and two parameters of gamma distribution (calculated from mean and standard deviation of wet-day rainfall) for simulating wet-day rainfall amounts. While two models with deterministic parameters underestimated long term variability, our investigation found that the long term variability of rainfall in the model is predominantly governed by the long term variability of gamma parameters, rather than the variability of Markov Chain parameters. Therefore, in the third approach, we developed the CDMC model with deterministic parameters of Markov Chain process, but stochastic parameters of gamma distribution by sampling the mean and standard deviation of wet-day rainfall from their log-normal and bivariate-normal distribution. We have found that the CDMC is able to replicate both short term and long term rainfall variability, when we calibrated the model at two sites in east coast of Australia using three types of daily rainfall data - (1) dynamically downscaled, 10 km resolution gridded data produced by NSW/ACT Regional Climate Modelling project, (2) 5 km resolution gridded data by Australian Water Availability Project and (3) point scale raingauge stations data by Bureau of Meteorology, Australia. We also examined the spatial variability of parameters and their link with local orography at our field site. The suitability of the model in runoff generation and urban reservoir-water simulation will be discussed.

  8. Long-term benefits of full-day kindergarten: a longitudinal population-based study

    PubMed Central

    Brownell, M.D.; Nickel, N.C.; Chateau, D.; Martens, P.J.; Taylor, C.; Crockett, L.; Katz, A.; Sarkar, J.; Burland, E.; Goh, C.Y.

    2015-01-01

    In the first longitudinal, population-based study of full-day kindergarten (FDK) outcomes beyond primary school in Canada, we used linked administrative data to follow 15 kindergarten cohorts (n ranging from 112 to 736) up to grade 9. Provincial assessments conducted in grades 3, 7, and 8 and course marks and credits earned in grade 9 were compared between FDK and half-day kindergarten (HDK) students in both targeted and universal FDK programmes. Propensity score matched cohort and stepped-wedge designs allowed for stronger causal inferences than previous research on FDK. We found limited long-term benefits of FDK, specific to the type of programme, outcomes examined, and subpopulations. FDK programmes targeted at low-income areas showed long-term improvements in numeracy for lower income girls. Our results suggest that expectations for wide-ranging long-term academic benefits of FDK are unwarranted. PMID:25632172

  9. Integrating acute and long-term care for high-cost populations.

    PubMed

    Master, R J; Eng, C

    2001-01-01

    The inadequacies of our fragmented acute and long-term care financing and delivery systems have been well recognized for many years. Yet over the past two decades only a very small number of "boutique" initiatives have been able to improve the financing and the delivery of care to chronically ill and disabled populations. These initiatives share most of the following characteristics: prepaid, risk-adjusted financing; integrated Medicare and Medicaid funding streams; a flexible array of acute and long-term benefits; well-organized, redesigned care delivery systems that tailor these benefits to individual need; a mission-driven philosophy; and considerable creativity in engaging government payers. The experience of these "boutiques" illustrates both the obstacles to, and the opportunity for, meaningful, widespread care delivery reform for vulnerable chronically ill populations. PMID:11816654

  10. [Impact of long-term continuous cropping on the Fusarium population in soybean rhizosphere].

    PubMed

    Wei, Wei; Xu, Yan-Li; Zhu, Lin; Zhang, Si-Jia; Li, S

    2014-02-01

    The impact of long-term continuous cropping on the Fusarium population abundance and diversity, pathogenicity and phylogeny in soybean field were analyzed by using isolation, morphological identification, pathogenicity test, sequencing analysis and molecular marker with restricted fragment length polymorphisms (RFLP). The soybean field was located at the Hailun Experimental Station of Agricultural Ecology of Chinese Academy of Sciences in Northeast China and had been under a long-term rotation experiment designed to two treatments, i. e., long-term continuous cropping (LCC) of soybean for 20 years and short-term continuous cropping (SCC) for 3 years. In SCC field, the population density of Fusarium spp. was 6.0 x 10(4) CFU x g(-1), in which F. oxysporum, F. graminearum and F. verticillioides possessing high pathogenicity and F. solani possessing moderate pathogenicity were the dominant species. In LCC field, the population density of Fusarium population and the dominance index of dominant species were significantly lower than that in SCC. The population density of F. oxysporum, F. graminearum and F. solani were only 36% , 32% and 22% of that in SCC, and F. verticillioide with highest pathogenicity was absent. The diversity and evenness index of Fusarium population were significantly higher than that in SCC. F. tricinctum, F. lateritium and F. avenaceum, just isolated from LCC, possessing a distant genetic relationship with Fusarium isolates possessing high pathogenicity based on internal transcribed spacer (ITS) and translation elongation factor 1-alpha (EF-1alpha) gene, were non-pathogenicity for soybean. Thus, it seemed that LCC of soybean could cause the inhibition of soil Fusarium population size, alteration of Fusarium community composition and genetic diversity, and even the decline of pathogenicity for soybean root rot disease of Fusarium population. PMID:24830251

  11. An optical model for implementing Parrondo's game and designing stochastic game with long-term memory

    NASA Astrophysics Data System (ADS)

    Si, Tieyan

    2012-11-01

    An optical model of classical photons propagating through array of many beam splitters is developed to give a physical analogy of Parrondo's game and Parrondo-Harmer-Abbott game. We showed both the two games are reasonable game without so-called game paradox and they are essentially the same. We designed the games with long-term memory on loop lattice and history-entangled game. The strong correlation between nearest two rounds of game can make the combination of two losing game win, lose or oscillate between win and loss. The periodic potential in Brownian ratchet is analogous to a long chain of beam splitters. The coupling between two neighboring potential wells is equivalent to two coupled beam splitters. This correspondence may help us to understand the anomalous motion of exceptional Brownian particles moving in the opposite direction to the majority. We designed the capital wave for a game by introducing correlations into independent capitals instead of sub-games. Playing entangled quantum states in many coupled classical games obey the same rules for manipulating quantum states in many body physics.

  12. 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

  13. Inversion polymorphism in two Serbian natural populations of Drosophila subobscura: analysis of long-term changes.

    PubMed

    Zivanovic, G; Arenas, C; Mestres, F

    2014-06-01

    To study whether inversions (or arrangements) by themselves or karyotypes are the main global warming adaptive target of natural selection, two Drosophila subobscura Serbian populations (Apatin and Petnica) were re-analyzed using different statistical approaches. Both populations were sampled in an approximately 15 years period: Apatin in 1994 and 2008 + 2009 and Petnica in 1995 and 2010. For all chromosomes, the four collections studied were in Hardy-Weinberg equilibrium. Thus, it seems that inversions (or arrangements) combined at random to constitute populations' karyotypes. However, there were differences in karyotypic frequencies along the years, although they were significant only for Apatin population. It is possible to conclude that inversions (or arrangements) are likely the target of natural selection, because they presented long-term changes, but combine at random to generate the corresponding karyotypic combinations. As a consequence, the frequencies of karyotypes also change along time.

  14. Temporal Population Genetics of Time Travelling Insects: A Long Term Study in a Seed-Specialized Wasp

    PubMed Central

    Lefèvre, François; Candau, Jean-Noël; Chalon, Alain; Boivin, Thomas

    2013-01-01

    Many animal species experiencing spatial or interannual fluctuations of their environment are capable of prolonged diapause, a kind of dormancy that extends over more than one year. Such a prolonged diapause is commonly perceived as a temporal demographic refuge in stochastic environments, but empirical evidence is still lacking of its consequences on temporal population genetic structures. In this long-term study, we investigated how a particular pattern of prolonged diapause may influence the temporal population genetics of the invasive seed-specialized wasp Megastigmus schimitscheki (Hymenoptera: Torymidae) in southeastern France. We characterized the diapause strategy of M. schimitscheki using records of emergence from diapause in 97 larval cohorts, and we conducted a temporal population genetic study on a natural invasive wasp population sampled during ten consecutive years (1999–2008) using polymorphic microsatellite markers. We found that M. schimitscheki can undergo a prolonged diapause of up to five years and displays two main adult emergence peaks after two and four years of diapause. Such a bimodal and atypical pattern did not disrupt temporal gene flow between cohorts produced in even and in odd years during the period of the study. Unexpectedly, we found that this wasp population consisted of two distinct genetic sub-populations that strongly diverged in their diapause strategies, with very few admixed individuals. One of the sub-populations displayed both short and prolonged diapause (2 and 4 years respectively) in equal proportions, whereas the other sub-population displayed mainly short diapause. This study provided empirical evidence that prolonged diapause phenotypes can substantially contribute to reproduction and impact temporal genetic structures. Prolonged diapause is likely to act as both demographic and genetic refuges for insect populations living in fluctuating environments. PMID:23936470

  15. Long-term survival following intensive care: subgroup analysis and comparison with the general population.

    PubMed

    Wright, J C; Plenderleith, L; Ridley, S A

    2003-07-01

    This study aimed to compare the very long-term survival of critically ill patients with that of the general population, and examine the association among age, sex, admission diagnosis, APACHE II score and mortality. In a retrospective observational cohort study of prospectively gathered data, 2104 adult patients admitted to the intensive care unit (ICU) of a teaching hospital in Glasgow from 1985 to 1992, were followed until 1997. Vital status at five years was compared with that of an age- and sex-matched Scottish population. Five-year mortality for the ICU patients was 47.1%, 3.4 times higher than that of the general population. For those surviving intensive care the five-year mortality was 33.4%. Mortality was greater than that of the general population for four years following intensive care unit admission (95% confidence interval included 1.0 at four years). Multivariate analysis showed that risk factors for mortality in those admitted to ICU were age, APACHE II score on admission and diagnostic category. Mortality was higher for those admitted with haematological (87.5%) and neurological diseases (61.7%) and septic shock (62.9%). A risk score was produced: Risk Score = 10 (age hazard ratio + APACHE II hazard ratio + diagnosis hazard ratio). None of the patients with a risk score > 100 survived more than five years and for those who survived to five years the mean risk score was 57. Long-term survival following intensive care is not only related to age and severity of illness but also diagnostic category. The risk of mortality in survivors of critical illness matches that of the normal population after four years. Age, severity of illness and diagnosis can be combined to provide an estimate of five-year survival.

  16. Climate effects and feedback structure determining weed population dynamics in a long-term experiment.

    PubMed

    Lima, Mauricio; Navarrete, Luis; González-Andujar, José Luis

    2012-01-01

    Pest control is one of the areas in which population dynamic theory has been successfully applied to solve practical problems. However, the links between population dynamic theory and model construction have been less emphasized in the management and control of weed populations. Most management models of weed population dynamics have emphasized the role of the endogenous process, but the role of exogenous variables such as climate have been ignored in the study of weed populations and their management. Here, we use long-term data (22 years) on two annual weed species from a locality in Central Spain to determine the importance of endogenous and exogenous processes (local and large-scale climate factors). Our modeling study determined two different feedback structures and climate effects in the two weed species analyzed. While Descurainia sophia exhibited a second-order feedback and low climate influence, Veronica hederifolia was characterized by a first-order feedback structure and important effects from temperature and rainfall. Our results strongly suggest the importance of theoretical population dynamics in understanding plant population systems. Moreover, the use of this approach, discerning between the effect of exogenous and endogenous factors, can be fundamental to applying weed management practices in agricultural systems and to controlling invasive weedy species. This is a radical change from most approaches currently used to guide weed and invasive weedy species managements.

  17. Climate Effects and Feedback Structure Determining Weed Population Dynamics in a Long-Term Experiment

    PubMed Central

    Lima, Mauricio; Navarrete, Luis; González-Andujar, José Luis

    2012-01-01

    Pest control is one of the areas in which population dynamic theory has been successfully applied to solve practical problems. However, the links between population dynamic theory and model construction have been less emphasized in the management and control of weed populations. Most management models of weed population dynamics have emphasized the role of the endogenous process, but the role of exogenous variables such as climate have been ignored in the study of weed populations and their management. Here, we use long-term data (22 years) on two annual weed species from a locality in Central Spain to determine the importance of endogenous and exogenous processes (local and large-scale climate factors). Our modeling study determined two different feedback structures and climate effects in the two weed species analyzed. While Descurainia sophia exhibited a second-order feedback and low climate influence, Veronica hederifolia was characterized by a first-order feedback structure and important effects from temperature and rainfall. Our results strongly suggest the importance of theoretical population dynamics in understanding plant population systems. Moreover, the use of this approach, discerning between the effect of exogenous and endogenous factors, can be fundamental to applying weed management practices in agricultural systems and to controlling invasive weedy species. This is a radical change from most approaches currently used to guide weed and invasive weedy species managements. PMID:22272362

  18. SY 04-2 LONG-TERM CVD RISK PREDICTION IN LOW-INCIDENCE EUROPEAN POPULATIONS.

    PubMed

    Veronesi, Giovanni

    2016-09-01

    In Italy, the European SCORE Project risk score is the recommended tool for cardiovascular disease risk stratification in the primary prevention setting. Among non-diabetic subjects aged 40 to 64, the model estimates the 10-year probability of death due to cardiovascular disease based on individual's age, total cholesterol, blood pressure and smoking status. A growing body of evidence suggests that in middle-aged adults this stratification may suffer from two major drawbacks. First, mortality risk severely underestimates the global burden of disease incidence. Second, younger individuals and women are likely to be classified in the "low 10-year risk" category despite the presence of risk factors.The latest European and American guidelines have eventually introduced the assessment of long-term risk of disease as additional tool to improve risk communication and increase risk awareness. Long-term risk scores were first developed in the US and in the UK, i.e. in high-risk populations. In low-incidence populations, these models may have poor calibration and discrimination ability, as shown for the Framingham equation. Therefore, our research team developed and validated a 20-year risk score for the Italian population. As part of a collaborative study with the Italian Health Institute, we pooled 7 population-based cohorts of middle-aged individuals recruited in Northern and in Central Italy in mid 1980 s and early 1990 s following a similar protocol with standardized MONICA procedures. Overall, more than 10500 men and women 35-69 years old and free of CVD at baseline, who developed 830 first major atherosclerotic events (coronary heart disease or ischemic strokes) during a median 17 years of follow-up. The score was based on traditional risk factors (age, blood lipids, systolic blood pressure and treatment, smoking and diabetes). In addition, social status and family history of coronary heart disease did improve risk prediction, at least in men. Finally we showed

  19. Population ageing and wellbeing: lessons from Japan's long-term care insurance policy.

    PubMed

    Tamiya, Nanako; Noguchi, Haruko; Nishi, Akihiro; Reich, Michael R; Ikegami, Naoki; Hashimoto, Hideki; Shibuya, Kenji; Kawachi, Ichiro; Campbell, John Creighton

    2011-09-24

    Japan's population is ageing rapidly because of long life expectancy and a low birth rate, while traditional supports for elderly people are eroding. In response, the Japanese Government initiated mandatory public long-term care insurance (LTCI) in 2000, to help older people to lead more independent lives and to relieve the burdens of family carers. LTCI operates on social insurance principles, with benefits provided irrespective of income or family situation; it is unusually generous in terms of both coverage and benefits. Only services are provided, not cash allowances, and recipients can choose their services and providers. Analysis of national survey data before and after the programme started shows increased use of formal care at lower cost to households, with mixed results for the wellbeing of carers. Challenges to the success of the system include dissatisfaction with home-based care, provision of necessary support for family carers, and fiscal sustainability. Japan's strategy for long-term care could offer lessons for other nations.

  20. Long Term Population, City Size and Climate Trends in the Fertile Crescent: A First Approximation.

    PubMed

    Lawrence, Dan; Philip, Graham; Hunt, Hannah; Snape-Kennedy, Lisa; Wilkinson, T J

    2016-01-01

    Over the last 8000 years the Fertile Crescent of the Near East has seen the emergence of urban agglomerations, small scale polities and large territorial empires, all of which had profound effects on settlement patterns. Computational approaches, including the use of remote sensing data, allow us to analyse these changes at unprecedented geographical and temporal scales. Here we employ these techniques to examine and compare long term trends in urbanisation, population and climate records. Maximum city size is used as a proxy for the intensity of urbanisation, whilst population trends are modelled from settlement densities in nine archaeological surveys conducted over the last 30 years across the region. These two measures are then compared with atmospheric moisture levels derived from multiple proxy analyses from two locations close to the study area, Soreq Cave in Israel and Lake Van in south-eastern Turkey, as well as wider literature. The earliest urban sites emerged during a period of relatively high atmospheric moisture levels and conform to a series of size thresholds. However, after the Early Bronze Age maximum urban size and population levels increase rapidly whilst atmospheric moisture declines. We argue that although the initial phase of urbanization may have been linked to climate conditions, we can see a definitive decoupling of climate and settlement patterns after 2000 BC. We relate this phenomenon to changes in socio-economic organisation and integration in large territorial empires. The complex relationships sustaining urban growth during this later period resulted in an increase in system fragility and ultimately impacted on the sustainability of cities in the long term.

  1. Retinal Microvasculature Is Associated With Long-Term Survival in the General Adult Dutch Population.

    PubMed

    Mutlu, Unal; Ikram, M Kamran; Wolters, Frank J; Hofman, Albert; Klaver, Caroline C W; Ikram, M Arfan

    2016-02-01

    Retinal vascular diameters are associated with (sub)clinical cardiovascular disease and short-term cardiovascular mortality, but their association with long-term mortality is uncertain. We studied the association of retinal vascular diameters with cause-specific mortality in the general adult Dutch population during 25 years of follow-up. From 1990 to 1993, arteriolar and venular diameters were measured semiautomatically on digitized images in 5674 persons (mean age 68.0 years, 59% women) from the population-based Rotterdam study. Follow-up for mortality was complete till March 2015. Associations between vascular diameters and mortality were examined using Cox proportional hazards models, adjusting for age, sex, cardiovascular risk factors, and the fellow vessel diameter. During 85 770 person-years (mean±SD: 15.1±6.67), 3794 (66.8%) persons died, of whom 1034 due to cardiovascular causes. We found that narrower arterioles and wider venules were associated with higher risk of mortality (adjusted hazard ratio [95% confidence interval] per SD decrease 1.04 [1.00-1.08] and increase 1.07 [1.03-1.12], respectively). For arterioles, these associations were strongest for cardiovascular mortality, whereas venules showed consistent associations for cardiovascular and noncardiovascular mortality. Importantly, these associations remained unchanged after excluding the first 10 years of follow-up as immortal person-time. We found evidence for effect modification with stronger associations in persons <70 years (venules only) and smokers (P value for interaction<0.01). We replicated our findings in another independent cohort from the Rotterdam Study of 3106 persons with 19 880 person-years of follow-up and 144 deaths (hazard ratio for venules 1.22 [1.00-1.49]). Markers of retinal microvasculature are associated with long-term mortality in the general adult Dutch population. PMID:26628677

  2. Long-term fracture risk among infertile women: a population-based cohort study.

    PubMed

    Melton, L J; Hesdorffer, D C; Malkasian, G D; Atkinson, E J; Brinton, L A; O'Fallon, W M

    2001-04-01

    Nulliparity has been linked to bone loss and fractures, but the contribution of infertility is unclear. The purpose of this study was to assess the long-term risk of fractures among infertile women. In a population-based retrospective cohort study, all 658 Olmsted County, Minnesota, women with infertility (failure to conceive after 1 year despite intercourse without contraception) first diagnosed at Mayo Clinic in 1935-1964 were followed for fractures. Risk was assessed by comparing new fractures of each type to the number expected from sex-specific and age-specific fracture rates in the general population (standardized incidence ratios [SIR]). During 18,130 person-years of follow-up, 184 women experienced at least one fracture when 291 would have been expected on the basis of fracture incidence rates in the general population (SIR 0.6, 95% CI 0.5-0.7). There was no increase in proximal femur fractures (SIR 1.0, 95% CI 0.6-1.6) and a statistically significant decrease in the risk of distal forearm fractures (SIR 0.7, 95% CI 0.5-0.97), two of the three sites traditionally associated with osteoporosis. By contrast, there was a significant increase in subsequent vertebral fractures (SIR 1.9, 95% CI 1.4-2.4) that was consistent across divergent causes of infertility and reported menstrual patterns. Although an apparent increase in the risk of vertebral fractures requires further investigation, we saw no indication of an increase in limb fractures, suggesting that infertility does not have long-term adverse skeletal effects like those reported for athletes and dieters with irregular menses.

  3. Long Term Population, City Size and Climate Trends in the Fertile Crescent: A First Approximation.

    PubMed

    Lawrence, Dan; Philip, Graham; Hunt, Hannah; Snape-Kennedy, Lisa; Wilkinson, T J

    2016-01-01

    Over the last 8000 years the Fertile Crescent of the Near East has seen the emergence of urban agglomerations, small scale polities and large territorial empires, all of which had profound effects on settlement patterns. Computational approaches, including the use of remote sensing data, allow us to analyse these changes at unprecedented geographical and temporal scales. Here we employ these techniques to examine and compare long term trends in urbanisation, population and climate records. Maximum city size is used as a proxy for the intensity of urbanisation, whilst population trends are modelled from settlement densities in nine archaeological surveys conducted over the last 30 years across the region. These two measures are then compared with atmospheric moisture levels derived from multiple proxy analyses from two locations close to the study area, Soreq Cave in Israel and Lake Van in south-eastern Turkey, as well as wider literature. The earliest urban sites emerged during a period of relatively high atmospheric moisture levels and conform to a series of size thresholds. However, after the Early Bronze Age maximum urban size and population levels increase rapidly whilst atmospheric moisture declines. We argue that although the initial phase of urbanization may have been linked to climate conditions, we can see a definitive decoupling of climate and settlement patterns after 2000 BC. We relate this phenomenon to changes in socio-economic organisation and integration in large territorial empires. The complex relationships sustaining urban growth during this later period resulted in an increase in system fragility and ultimately impacted on the sustainability of cities in the long term. PMID:27018998

  4. Long Term Population, City Size and Climate Trends in the Fertile Crescent: A First Approximation

    PubMed Central

    Lawrence, Dan; Philip, Graham; Hunt, Hannah; Snape-Kennedy, Lisa; Wilkinson, T. J.

    2016-01-01

    Over the last 8000 years the Fertile Crescent of the Near East has seen the emergence of urban agglomerations, small scale polities and large territorial empires, all of which had profound effects on settlement patterns. Computational approaches, including the use of remote sensing data, allow us to analyse these changes at unprecedented geographical and temporal scales. Here we employ these techniques to examine and compare long term trends in urbanisation, population and climate records. Maximum city size is used as a proxy for the intensity of urbanisation, whilst population trends are modelled from settlement densities in nine archaeological surveys conducted over the last 30 years across the region. These two measures are then compared with atmospheric moisture levels derived from multiple proxy analyses from two locations close to the study area, Soreq Cave in Israel and Lake Van in south-eastern Turkey, as well as wider literature. The earliest urban sites emerged during a period of relatively high atmospheric moisture levels and conform to a series of size thresholds. However, after the Early Bronze Age maximum urban size and population levels increase rapidly whilst atmospheric moisture declines. We argue that although the initial phase of urbanization may have been linked to climate conditions, we can see a definitive decoupling of climate and settlement patterns after 2000 BC. We relate this phenomenon to changes in socio-economic organisation and integration in large territorial empires. The complex relationships sustaining urban growth during this later period resulted in an increase in system fragility and ultimately impacted on the sustainability of cities in the long term. PMID:27018998

  5. Introducing health gains in location-allocation models: A stochastic model for planning the delivery of long-term care

    NASA Astrophysics Data System (ADS)

    Cardoso, T.; Oliveira, M. D.; Barbosa-Póvoa, A.; Nickel, S.

    2015-05-01

    Although the maximization of health is a key objective in health care systems, location-allocation literature has not yet considered this dimension. This study proposes a multi-objective stochastic mathematical programming approach to support the planning of a multi-service network of long-term care (LTC), both in terms of services location and capacity planning. This approach is based on a mixed integer linear programming model with two objectives - the maximization of expected health gains and the minimization of expected costs - with satisficing levels in several dimensions of equity - namely, equity of access, equity of utilization, socioeconomic equity and geographical equity - being imposed as constraints. The augmented ε-constraint method is used to explore the trade-off between these conflicting objectives, with uncertainty in the demand and delivery of care being accounted for. The model is applied to analyze the (re)organization of the LTC network currently operating in the Great Lisbon region in Portugal for the 2014-2016 period. Results show that extending the network of LTC is a cost-effective investment.

  6. Influence of melanin on mutation load in Drosophila populations after long-term irradiation

    SciTech Connect

    Mosse, I.B.; Lyakh, I.P.

    1994-09-01

    The effect of melanin on the level of mutation load has been studied in experimental Drosophila populations exposed to radiation for 115 generations. Four types of populations have been analyzed: (1) control; (2) treated with melanin; (3) irradiated; (4) irradiated and treated with melanin. Melanin was produced by auto-oxidation of 1-dioxyphenylallanine and was constantly added to food. Populations were X-irradiated twice in each generation (at the larvae stage with 6 Gy and at the imago stage with 9 Gy). The level of recessive mutation on the third chromosome was analyzed by a standard genetic method of balanced lethals. The data obtained have shown that the populations exposed to long-term irradiation have the greatest number of mutations decreasing viability. Melanin exhibited radioprotective properties-it reduced the percentage of lethal, semilethal and subvital mutations. Thus the possibility of effective protection of populations exposed to radiation for many generations by melanin has been shown for the first time. 19 refs., 1 fig., 1 tab.

  7. Effects of long-term chronic exposure to radionuclides in plant populations.

    PubMed

    Geras'kin, S; Evseeva, T; Oudalova, A

    2013-07-01

    The results of field studies carried out on different plant species (winter rye and wheat, spring barley, oats, Scots pine, wild vetch, crested hairgrass) in various radioecological situations (nuclear weapon testing, the Chernobyl accident, uranium and radium processing) to investigate the effects of long-term chronic exposure to radionuclides are discussed. Plant populations growing in areas with relatively low levels of pollution are characterized by an increased level of both cytogenetic disturbances and genetic diversity. Although ionizing radiation causes primary damage at the molecular level, there are emergent effects at the level of populations, non-predictable from the knowledge of elementary mechanisms of cellular effects formation. Accumulation of cellular alterations may afterward influence biological parameters important for populations such as health and reproduction. Presented data provide evidence that in plant populations inhabiting heavily contaminated territories cytogenetic damage could be accompanied by a decrease in reproductive capacity. However, in less contaminated sites, because of the scarcity of data available, a steady relationship between cytogenetic effects and reproductive capacity was not revealed. Under radioactive contamination of the plant's environment, a population's resistance to exposure may increase. However, there are radioecological situations where an enhanced radioresistance has not evolved or has not persisted. PMID:22483340

  8. Reversibility of T helper 1 and 2 populations is lost after long-term stimulation

    PubMed Central

    1996-01-01

    Commitment of T helper 1 (Th1) or Th2 populations developing during an immune response to a pathogen, or an inappropriate immune response to an allergen or autoantigen, may determine the difference between health and chronic disease. We show that strongly polarized Th1 and Th2 populations assessed by immunoassay are heterogeneous using flow cytometry to detect single cells producing interferon gamma (IFN-gamma) and interleukin 4 (IL-4). Th1 populations arising after 1 wk of stimulation in IL-12 plus anti-IL-4 antibodies could convert to Th2 cells when restimulated in IL-4. Th2 populations resulting from stimulation for 1 wk in IL-4 could give rise to Th1 cells upon restimulation in IL-12 plus anti-IL-4. In contrast, the cytokine profiles of long-term Th1 and Th2 populations arising originally from repeated stimulation in IL-12 or IL-4 appeared more homogeneous and were not reversible, although IL-4 dramatically reduced the number of IFN-gamma-producing Th1 cells. This may explain previous reports that Th1 cells can be converted to Th2 cells. PMID:8642294

  9. Standardizing flow cytometric assays in long-term population-based studies

    NASA Astrophysics Data System (ADS)

    Melzer, Susanne; Bocsi, Jozsef; Tárnok, Attila

    2015-03-01

    Quantification of leukocyte subpopulations and characterization of antigen-expression pattern on the cellular surface can play an important role in diagnostics. The state of cellular immunology on the single-cell level was analyzed by polychromatic flow cytometry in a recent comparative study within the average Leipzig population (LIFE - Leipzig Research Centre for Civilization Diseases). Data of 1699 subjects were recorded over a long-time period of three years (in a total of 1126 days). To ensure compatibility of such huge data sets, quality-controls on many levels (stability of instrumentation, low intra-laboratory variance and reader independent data analysis) are essential. The LIFE study aims to analyze various cytometric pattern to reveal the relationship between the life-style, the environmental effects and the individual health. We therefore present here a multi-step quality control procedure for long-term comparative studies.

  10. Local Competition and Metapopulation Processes Drive Long-Term Seagrass-Epiphyte Population Dynamics

    PubMed Central

    Lobelle, Delphine; Kenyon, Emma J.; Cook, Kevan J.; Bull, James C.

    2013-01-01

    It is well known that ecological processes such as population regulation and natural enemy interactions potentially occur over a range of spatial scales, and there is a substantial body of literature developing theoretical understanding of the interplay between these processes. However, there are comparatively few studies quantifying the long-term effects of spatial scaling in natural ecosystems. A key challenge is that trophic complexity in real-world biological communities quickly obscures the signal from a focal process. Seagrass meadows provide an excellent opportunity in this respect: in many instances, seagrasses effectively form extensive natural monocultures, in which hypotheses about endogenous dynamics can be formulated and tested. We present amongst the longest unbroken, spatially explict time series of seagrass abundance published to date. Data include annual measures of shoot density, total above-ground abundance, and associated epiphyte cover from five Zostera marina meadows distributed around the Isles of Scilly, UK, from 1996 to 2011. We explore empirical patterns at the local and metapopulation scale using standard time series analysis and develop a simple population dynamic model, testing the hypothesis that both local and metapopulation scale feedback processes are important. We find little evidence of an interaction between scales in seagrass dynamics but that both scales contribute approximately equally to observed local epiphyte abundance. By quantifying the long-term dynamics of seagrass-epiphyte interactions we show how measures of density and extent are both important in establishing baseline information relevant to predicting responses to environmental change and developing management plans. We hope that this study complements existing mechanistic studies of physiology, genetics and productivity in seagrass, whilst highlighting the potential of seagrass as a model ecosystem. More generally, this study provides a rare opportunity to test

  11. Long-term musculoskeletal morbidity after adult burn injury: a population-based cohort study

    PubMed Central

    Randall, Sean M; Fear, Mark W; Wood, Fiona M; Rea, Suzanne; Boyd, James H; Duke, Janine M

    2015-01-01

    Objective To investigate if adults who are hospitalised for a burn injury have increased long-term hospital use for musculoskeletal diseases. Design A population-based retrospective cohort study using linked administrative health data from the Western Australian Data Linkage System. Subjects Records of 17 753 persons aged at least 20 years when hospitalised for a first burn injury in Western Australia during the period 1980–2012, and 70 758 persons who were age and gender-frequency matched with no injury admissions randomly selected from Western Australia's electoral roll. Main outcome measures Admission rates and cumulative length of stay for musculoskeletal diseases. Negative binomial and Cox proportional hazards regression modelling were used to generate incidence rate ratios (IRR) and HRs with 95% CIs, respectively. Results After adjustment for pre-existing health status and demographic characteristics, the burn cohort had almost twice the hospitalisation rate for a musculoskeletal condition (IRR, 95% CI 1.98, 1.86 to 2.10), and spent 3.70 times as long in hospital with a musculoskeletal diagnosis (95% CI 3.10 to 4.42) over the 33-year period, than the uninjured comparison cohort. Adjusted survival analyses of incident post-burn musculoskeletal disease admissions found significant increases for the 15-year post burn discharge period (0–6 months: HR, 95% CI 2.51, 2.04 to 3.11; 6 months–2 years: HR, 95% CI 1.77, 1.53 to 2.05; 2–15 years: HR, 95% CI 1.32, 1.23 to 1.42). Incident admission rates were significantly elevated for 20 years post-burn for minor and severe burn injury for a range of musculoskeletal diseases that included arthropathies, dorsopathies, osteopathies and soft tissue disorders. Conclusions Minor and severe burn injuries were associated with significantly increased post-burn incident admission rates, long-term hospital use and prolonged length of stay for a range of musculoskeletal diseases. Further research is required

  12. Long-term population dynamics of breeding bird species in the German Wadden Sea area

    NASA Astrophysics Data System (ADS)

    Vauk, Gottfried; Prüter, Johannes; Hartwig, Eike

    1989-09-01

    For no other group of organisms in coastal areas are there so exact and long-term data available as there are for seabirds. Since the beginning of the 20th century, documentation of population size, especially for species breeding in colonies from the groups gulls, terns and auks, is almost complete. These species act as bio-indicators, and data on fluctuations in their population size are useful as they reflect changes in the state of the marine ecosystem. The population development of some of these seabird species (Herring Gull, Guillemot, Common, Arctic and Sandwich Tern) from the German North Sea coast, which primarily feed on fish, is given. Common to all these species is an exponential increase in numbers in recent years (1970 1985). Possible causes for this development, e.g. pressure from enemies or competitors, availability of breeding places, anthropogenic stress and mortality factors, as well as the direct and indirect anthropogenic-influenced changes in the trophic system due to the increasing eutrophication of coastal waters, are evaluated. Signs of a collapse in the stocks of seabrids resulting from environmental pollution are discussed. Consequences resulting from the ecosystem changes, such as reduction of nutrient discharge into the North Sea and the expansion of biological monitoring, are described.

  13. Geriatrics and the triple aim: defining preventable hospitalizations in the long-term care population.

    PubMed

    Ouslander, Joseph G; Maslow, Katie

    2012-12-01

    Reducing preventable hospitalizations is fundamental to the "triple aim" of improving care, improving health, and reducing costs. New federal government initiatives that create strong pressure to reduce such hospitalizations are being or will soon be implemented. These initiatives use quality measures to define which hospitalizations are preventable. Reducing hospitalizations could greatly benefit frail and chronically ill adults and older people who receive long-term care (LTC) because they often experience negative effects of hospitalization, including hospital-acquired conditions, morbidity, and loss of functional abilities. Conversely, reducing hospitalizations could mean that some people will not receive hospital care they need, especially if the selected measures do not adequately define hospitalizations that can be prevented without jeopardizing the person's health and safety. An extensive literature search identified 250 measures of preventable hospitalizations, but the measures have not been validated in the LTC population and generally do not account for comorbidity or the capacity of various LTC settings to provide the required care without hospitalization. Additional efforts are needed to develop measures that accurately differentiate preventable from necessary hospitalizations for the LTC population, are transparent and fair to providers, and minimize the potential for gaming and unintended consequences. As the new initiatives take effect, it is critical to monitor their effect and to develop and disseminate training and resources to support the many community- and institution-based healthcare professionals and emergency department staff involved in decisions about hospitalization for this population. PMID:23194066

  14. Long-term effects of timber harvesting on hemicellulolytic microbial populations in coniferous forest soils.

    PubMed

    Leung, Hilary T C; Maas, Kendra R; Wilhelm, Roland C; Mohn, William W

    2016-02-01

    Forest ecosystems need to be sustainably managed, as they are major reservoirs of biodiversity, provide important economic resources and modulate global climate. We have a poor knowledge of populations responsible for key biomass degradation processes in forest soils and the effects of forest harvesting on these populations. Here, we investigated the effects of three timber-harvesting methods, varying in the degree of organic matter removal, on putatively hemicellulolytic bacterial and fungal populations 10 or more years after harvesting and replanting. We used stable-isotope probing to identify populations that incorporated (13)C from labeled hemicellulose, analyzing (13)C-enriched phospholipid fatty acids, bacterial 16 S rRNA genes and fungal ITS regions. In soil microcosms, we identified 104 bacterial and 52 fungal hemicellulolytic operational taxonomic units (OTUs). Several of these OTUs are affiliated with taxa not previously reported to degrade hemicellulose, including the bacterial genera Methylibium, Pelomonas and Rhodoferax, and the fungal genera Cladosporium, Pseudeurotiaceae, Capronia, Xenopolyscytalum and Venturia. The effect of harvesting on hemicellulolytic populations was evaluated based on in situ bacterial and fungal OTUs. Harvesting treatments had significant but modest long-term effects on relative abundances of hemicellulolytic populations, which differed in strength between two ecozones and between soil layers. For soils incubated in microcosms, prior harvesting treatments did not affect the rate of incorporation of hemicellulose carbon into microbial biomass. In six ecozones across North America, distributions of the bacterial hemicellulolytic OTUs were similar, whereas distributions of fungal ones differed. Our work demonstrates that diverse taxa in soil are hemicellulolytic, many of which are differentially affected by the impact of harvesting on environmental conditions. However, the hemicellulolytic capacity of soil communities appears

  15. Long-term population dynamics of a managed burrowing owl colony

    USGS Publications Warehouse

    Barclay, John H.; Korfanta, Nicole M.; Kauffman, Matthew J.

    2011-01-01

    We analyzed the population dynamics of a burrowing owl (Athene cunicularia) colony at Mineta San Jose International Airport in San Jose, California, USA from 1990-2007. This colony was managed by using artificial burrows to reduce the occurrence of nesting owls along runways and within major airport improvement projects during the study period. We estimated annual reproduction in natural and artificial burrows and age-specific survival rates with mark-recapture techniques, and we estimated the relative contribution of these vital rates to population dynamics using a life table response experiment. The breeding colony showed 2 distinct periods of change: high population growth from 7 nesting pairs in 1991 to 40 pairs in 2002 and population decline to 17 pairs in 2007. Reproduction was highly variable: annual nesting success (pairs that raised =1 young) averaged 79% and ranged from 36% to 100%, whereas fecundity averaged 3.36 juveniles/pair and ranged from 1.43 juveniles/pair to 4.54 juveniles/pair. We estimated annual adult survival at 0.710 during the period of colony increase from 1996 to 2001 and 0.465 during decline from 2002 to 2007, but there was no change in annual survival of juveniles between the 2 time periods. Long-term population growth rate (lambda) estimated from average vital rates was lambdaa=1.072 with lambdai=1.288 during colony increase and lambdad=0.921 (DELTA lambda=0.368) during decline. A life table response experiment showed that change in adult survival rate during increasing and declining phases explained more than twice the variation in growth rate than other vital rates. Our findings suggest that management and conservation of declining burrowing owl populations should address factors that influence adult survival.

  16. Long-term effects of timber harvesting on hemicellulolytic microbial populations in coniferous forest soils.

    PubMed

    Leung, Hilary T C; Maas, Kendra R; Wilhelm, Roland C; Mohn, William W

    2016-02-01

    Forest ecosystems need to be sustainably managed, as they are major reservoirs of biodiversity, provide important economic resources and modulate global climate. We have a poor knowledge of populations responsible for key biomass degradation processes in forest soils and the effects of forest harvesting on these populations. Here, we investigated the effects of three timber-harvesting methods, varying in the degree of organic matter removal, on putatively hemicellulolytic bacterial and fungal populations 10 or more years after harvesting and replanting. We used stable-isotope probing to identify populations that incorporated (13)C from labeled hemicellulose, analyzing (13)C-enriched phospholipid fatty acids, bacterial 16 S rRNA genes and fungal ITS regions. In soil microcosms, we identified 104 bacterial and 52 fungal hemicellulolytic operational taxonomic units (OTUs). Several of these OTUs are affiliated with taxa not previously reported to degrade hemicellulose, including the bacterial genera Methylibium, Pelomonas and Rhodoferax, and the fungal genera Cladosporium, Pseudeurotiaceae, Capronia, Xenopolyscytalum and Venturia. The effect of harvesting on hemicellulolytic populations was evaluated based on in situ bacterial and fungal OTUs. Harvesting treatments had significant but modest long-term effects on relative abundances of hemicellulolytic populations, which differed in strength between two ecozones and between soil layers. For soils incubated in microcosms, prior harvesting treatments did not affect the rate of incorporation of hemicellulose carbon into microbial biomass. In six ecozones across North America, distributions of the bacterial hemicellulolytic OTUs were similar, whereas distributions of fungal ones differed. Our work demonstrates that diverse taxa in soil are hemicellulolytic, many of which are differentially affected by the impact of harvesting on environmental conditions. However, the hemicellulolytic capacity of soil communities appears

  17. Jensen's Inequality and the Impact of Short-Term Environmental Variability on Long-Term Population Growth Rates.

    PubMed

    Pickett, Evan J; Thomson, David L; Li, Teng A; Xing, Shuang

    2015-01-01

    It is well established in theory that short-term environmental fluctuations could affect the long-term growth rates of wildlife populations, but this theory has rarely been tested and there remains little empirical evidence that the effect is actually important in practice. Here we develop models to quantify the effects of daily, seasonal, and yearly temperature fluctuations on the average population growth rates, and we apply them to long-term data on the endangered Black-faced Spoonbill (Platalea minor); an endothermic species whose population growth rates follow a concave relationship with temperature. We demonstrate for the first time that the current levels of temperature variability, particularly seasonal variability, are already large enough to substantially reduce long-term population growth rates. As the climate changes, our results highlight the importance of considering the ecological effects of climate variability and not just average conditions. PMID:26352857

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

    ERIC Educational Resources Information Center

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

    2005-01-01

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

  19. Seasonal Fluctuations and Long-Term Persistence of Pathogenic Populations of Agrobacterium spp. in Soils

    PubMed Central

    Krimi, Z.; Petit, A.; Mougel, C.; Dessaux, Y.; Nesme, X.

    2002-01-01

    Short- and long-term persistence of pathogenic (i.e., tumor forming) agrobacteria in soil was investigated in six nursery plots with a history of high crown gall incidence. No pathogenic Agrobacterium strains were isolated in soil samples taken in fall and winter in any plots, but such strains were isolated from both bulk soils and weed rhizospheres (over 0.5 × 105 pathogenic CFU/g of bulk soil or rhizosphere) in three out of six plots in spring and summer. PCR amplifications of a vir sequence from DNA extracted from soil confirmed the presence of Ti plasmids in summer and their absence in fall and winter. The results indicate that strains that harbor a Ti plasmid had an unforeseen positive fitness versus Ti plasmid-free strains in soil and rhizosphere in spring and summer in spite of the apparent absence of tumor, and hence of opines. The gain of fitness occurred during a bloom of all cultivable agrobacteria observed only in conducive soils. An evolution of the pathogenic population was recorded during a 4-year period in one particularly conducive soil. In 1990, the pathogenic population in this soil consisted of only biovar 1 strains harboring both octopine- and nopaline-type Ti plasmids. In 1994, it consisted of only nopaline-type Ti plasmids equally distributed among biovar 1 and 2 strains. These results suggest that nopaline-type Ti plasmids conferred a better survival ability than octopine-type Ti plasmids to biovar 2 agrobacteria under the present field conditions. PMID:12089015

  20. Long-term imaging of circadian locomotor rhythms of a freely crawling C. elegans population

    PubMed Central

    Winbush, Ari; Gruner, Matthew; Hennig, Grant W.; van der Linden, Alexander M.

    2016-01-01

    Background Locomotor activity is used extensively as a behavioral output to study the underpinnings of circadian rhythms. Recent studies have required a populational approach for the study of circadian rhythmicity in Caenorhabditis elegans locomotion. New method We describe an imaging system for long-term automated recording and analysis of locomotion data of multiple free-crawling C. elegans animals on the surface of an agar plate. We devised image analysis tools for measuring specific features related to movement and shape to identify circadian patterns. Results We demonstrate the utility of our system by quantifying circadian locomotor rhythms in wild-type and mutant animals induced by temperature cycles. We show that 13 °C:18 °C (12:12 h) cycles are sufficient to entrain locomotor activity of wild-type animals, which persist but are rapidly damped during 13 °C free-running conditions. Animals with mutations in tax-2, a cyclic nucleotide-gated (CNG) ion channel, significantly reduce locomotor activity during entrainment and free-running. Comparison with existing method(s) Current methods for measuring circadian locomotor activity is generally restricted to recording individual swimming animals of C. elegans, which is a distinct form of locomotion from crawling behavior generally observed in the laboratory. Our system works well with up to 20 crawling adult animals, and allows for a detailed analysis of locomotor activity over long periods of time. Conclusions Our population-based approach provides a powerful tool for quantification of circadian rhythmicity of C. elegans locomotion, and could allow for a screening system of candidate circadian genes in this model organism. PMID:25911068

  1. Long-term follow-up of congenital esotropia in a population-based cohort

    PubMed Central

    Louwagie, Curtis R.; Diehl, Nancy N.; Greenberg, Amy E.; Mohney, Brian G.

    2009-01-01

    PURPOSE To report the long-term outcomes of a population-based cohort of children diagnosed with congenital esotropia during a 30-year period. METHODS The medical records of all patients diagnosed with congenital esotropia as residents of Olmsted County, MN, from January 1, 1965, through December 31, 1994, were retrospectively reviewed. RESULTS A total of 130 children were diagnosed during the 30-year period at a median age of 7.4 months with a mean deviation of 30Δ. During a median follow-up of 11.9 years, 126 patients underwent a mean of 1.8 strabismus surgeries. The risk for undergoing a second surgery was significantly greater in patients with a larger presenting angle (p = 0.017) and a younger age at first surgery (p = 0.006). The Kaplan-Meier rate of having a second surgery was 51% at 10 years and 66% at 20 years. For those with 6 weeks or more of follow-up from the final surgery, last examined at a mean age of 15.1 years, 42 of 94 (45%) were within 8Δ of orthotropia and 30 of 98 had some level of stereopsis (≤3000 arcsec). CONCLUSIONS In this population-based study of children with congenital esotropia, a second surgery was necessary in half the patients after 10 years and was more likely in those patients with a larger presenting angle and a younger age at first surgery. Approximately half of the patients were within 8Δ of orthotropia and one-third had measurable stereopsis after a mean of 10.9 years of follow-up. PMID:18993096

  2. Long-term population monitoring: Lessons learned from an endangered passerine in Hawai‘i

    USGS Publications Warehouse

    Johnson, Luanne; Camp, Richard J.; Brinck, Kevin W.; Banko, Paul C.

    2006-01-01

    interpretation were regeneration of trees in response to reduced numbers of introduced browsing mammals, seasonally variable rates of vocalization, non-territoriality, and resource-tracking along an elevation gradient. We believe our adaptive approach to analysis and interpretation of 25 years of annual variable circular plot data could help guide similar long-term monitoring efforts.

  3. The Association Between Natural Amenities, Rural Population Growth, and Long-Term Residents’ Economic Well-Being*

    PubMed Central

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

    2011-01-01

    Population growth in rural areas characterized by high levels of natural amenities has recently received substantial research attention. A noted concern with amenity-driven rural population growth is its potential to raise local costs-of-living while yielding only low-wage service sector employment for long-term residents. The work presented here empirically models long-term rural residents’ economic well-being, making use of longitudinal data from the Panel Study of Income Dynamics. In general, the results suggest that long-term rural families residing in high-growth amenity and recreation areas tend to have higher annual incomes than do their counterparts in non-growth amenity/recreation areas, regardless of the sex, race, or age of the family head. However, higher costs-of-living in these areas supplant any relative gains in income. As such, these analyses provide empirical evidence of patterns inferred by earlier anecdotal evidence and case studies. PMID:21874070

  4. The CD44+ALDH+ Population of Human Keratinocytes Is Enriched for Epidermal Stem Cells with Long-Term Repopulating Ability

    PubMed Central

    Szabo, Akos Z.; Fong, Stephen; Yue, Lili; Zhang, Kai; Strachan, Lauren R.; Scalapino, Kenneth; Mancianti, Maria Laura; Ghadially, Ruby

    2014-01-01

    Like for other somatic tissues, isolation of a pure population of stem cells has been a primary goal in epidermal biology. We isolated discrete populations of freshly obtained human neonatal keratinocytes (HNKs) using previously untested candidate stem cell markers aldehyde dehydrogenase (ALDH) and CD44 as well as the previously studied combination of integrin α6 and CD71. An in vivo transplantation assay combined with limiting dilution analysis was used to quantify enrichment for long-term repopulating cells in the isolated populations. The ALDH+CD44+ population was enriched 12.6-fold for long-term repopulating epidermal stem cells (EpiSCs) and the integrin α6hiCD71lo population was enriched 5.6-fold, over unfractionated cells. In addition to long-term repopulation, CD44+ALDH+ keratinocytes exhibited other stem cell properties. CD44+ALDH+ keratinocytes had self-renewal ability, demonstrated by increased numbers of cells expressing nuclear Bmi-1, serial transplantation of CD44+ALDH+ cells, and holoclone formation in vitro. CD44+ALDH+ cells were multipotent, producing greater numbers of hair follicle-like structures than CD44−ALDH− cells. Furthermore, 58% ± 7% of CD44+ALDH+ cells exhibited label-retention. In vitro, CD44+ALDH+ cells showed enhanced colony formation, in both keratinocyte and embryonic stem cell growth media. In summary, the CD44+ALDH+ population exhibits stem cell properties including long-term epidermal regeneration, multipotency, label retention, and holoclone formation. This study shows that it is possible to quantify the relative number of EpiSCs in human keratinocyte populations using long-term repopulation as a functional test of stem cell nature. Future studies will combine isolation strategies as dictated by the results of quantitative transplantation assays, in order to achieve a nearly pure population of EpiSCs. PMID:23335266

  5. Tibial stress fractures in an active duty population: long-term outcomes.

    PubMed

    Kilcoyne, Kelly G; Dickens, Jonathan F; Rue, John-Paul

    2013-01-01

    Tibial stress fractures are a common overuse injury among military recruits. The purpose of this study was to determine what, if any, long-term effects that tibial stress fractures have on military personnel with respect to physical activity level, completion of military training, recurrence of symptoms, and active duty service. Twenty-six military recruits included in a previous tibial stress fracture study were contacted 10 years after initial injury and asked a series of questions related to any long-term consequences of their tibial stress fracture. Of the 13 patients available for contact, no patients reported any necessary limited duty while on active duty, and no patient reported being separated or discharged from the military as a result of stress fracture. Tibial stress fractures in military recruits are most often an isolated injury and do not affect ability to complete military training or reflect a long-term need for decreased physical activity.

  6. Importance of climate, forest fires and human population size on the long-term boreal forest dynamics in Northern Europe

    NASA Astrophysics Data System (ADS)

    Kuosmanen, Niina; Seppä, Heikki; Alenius, Teija; Bradshaw, Richard; Clear, Jennifer; Filimonova, Fludmila; Heikkilä, Maija; Renssen, Hans; Tallavaara, Miikka; Reitalu, Triin

    2016-04-01

    Palaeoecological data provides valuable information for understanding the processes behind the past changes in forest composition, and hence can provide important knowledge regarding the potential effects of future changes in climate on boreal vegetation. Furthermore, it is essential to consider both regional and local factors in order to better understand the processes behind the boreal forest dynamics. The relative importance of climate, forest fires and human population size on long-term boreal forest composition were statistically investigated at regional and local scales in Fennoscandia. Statistical method variation partitioning was employed to assess the relative importance of these three variables. Fossil pollen data reflecting long-term boreal forest composition, at both regional (lake records) and local (small hollow records) scales from Russia, Finland and Sweden, were used as response matrix. Climate, generated from a climate model and oxygen isotope data, past forest fires generated from sedimentary charcoal data and human population size derived from radiocarbon dated archaeological findings were used as potential drivers of long-term boreal vegetation. Though the results clearly demonstrate that climate is the main driver of long-term vegetation changes at the regional scale, the role of climate notably is smaller at local scale and the influence of local site specific factors increases. However, the relative importance of forest fires on long-term changes in boreal forest composition remain generally low both at regional and local scale. The relatively low importance of both climate and forest fires on the variation in long-term boreal forest composition at local scale demonstrates the complexity of factors affecting stand-scale forest dynamics. In general, the relative importance of human population size on long-term changes in boreal vegetation was low. However, this was the first time that this type of human population size data was statistically

  7. Orthostatic Hypotension and the Long-Term Risk of Dementia: A Population-Based Study

    PubMed Central

    Wolters, Frank J.; Mattace-Raso, Francesco U. S.; Hofman, Albert; Ikram, M. Arfan

    2016-01-01

    .00–1.17, p = 0.06). The risk of dementia was particularly increased in those with OH who lacked a compensatory increase in heart rate (within lowest quartile of heart rate response: aHR 1.39, 95% CI 1.04–1.85, p-interaction = 0.05). Limitations of this study include potential residual confounding despite rigorous adjustments, and potentially limited generalisability to populations not of European descent. Conclusions In this population predominantly of European descent, OH was associated with an increase in long-term risk of dementia. PMID:27727284

  8. Long-term outcome of epilepsy surgery: a retrospective study in a population of 379 cases.

    PubMed

    Yu, Shengkun; Lin, Zhiguo; Liu, Li; Pu, Song; Wang, Haiyang; Wang, Jiabin; Xie, Chuncheng; Yang, Changlin; Li, Meng; Shen, Hong

    2014-03-01

    We evaluated the long-term outcome of epilepsy surgery in drug-resistant epilepsy patients, and investigated preoperative factors associated with postoperative long-term surgical outcome. We performed a retrospective study of 379 patients who received epilepsy surgeries from 2000 to 2010. Patients had completed a minimum of 2-year and up to 12-year follow-up. Preoperative evaluations, surgical outcomes and clinical data of patients were collected and analyzed. We found that the epilepsy surgery was effective in drug-resistant patients and the long-term outcome of epilepsy surgery was satisfactory. The bipolar electro-coagulation could improve the surgical outcome when the epileptogenic focus was on the functional cortex. Results of the 2-year follow-up showed that preoperative seizure characteristics including the history of febrile seizure, seizure frequency, and location, quantity and range of seizure foci were significantly associated with the surgical outcome. The surgery procedure including the surgery type and the extent of resection also affected outcome. Abnormal head or hippocampus MRI, inconsistent results of preoperative investigations, seizure types, and pathology type might also be predictors of long-term surgical outcome. PMID:24461543

  9. Changes in microbial populations of WPC34 and WPC80 whey protein during long term storage

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The use of whey protein (WPC34 and WPC80) as a food ingredient and as a base for making biodegradable products is increasing. The need to alleviate world hunger in arid and semi-arid regions demands that we investigate the behavior of native bacteria in these products, especially during long term st...

  10. Long-term outcome of epilepsy surgery: a retrospective study in a population of 379 cases.

    PubMed

    Yu, Shengkun; Lin, Zhiguo; Liu, Li; Pu, Song; Wang, Haiyang; Wang, Jiabin; Xie, Chuncheng; Yang, Changlin; Li, Meng; Shen, Hong

    2014-03-01

    We evaluated the long-term outcome of epilepsy surgery in drug-resistant epilepsy patients, and investigated preoperative factors associated with postoperative long-term surgical outcome. We performed a retrospective study of 379 patients who received epilepsy surgeries from 2000 to 2010. Patients had completed a minimum of 2-year and up to 12-year follow-up. Preoperative evaluations, surgical outcomes and clinical data of patients were collected and analyzed. We found that the epilepsy surgery was effective in drug-resistant patients and the long-term outcome of epilepsy surgery was satisfactory. The bipolar electro-coagulation could improve the surgical outcome when the epileptogenic focus was on the functional cortex. Results of the 2-year follow-up showed that preoperative seizure characteristics including the history of febrile seizure, seizure frequency, and location, quantity and range of seizure foci were significantly associated with the surgical outcome. The surgery procedure including the surgery type and the extent of resection also affected outcome. Abnormal head or hippocampus MRI, inconsistent results of preoperative investigations, seizure types, and pathology type might also be predictors of long-term surgical outcome.

  11. Burn injury and long-term nervous system morbidity: a population-based cohort study

    PubMed Central

    Vetrichevvel, Thirthar P; Randall, Sean M; Fear, Mark W; Wood, Fiona M; Boyd, James H; Duke, Janine M

    2016-01-01

    Objective To investigate if children and adults who are hospitalised for a burn injury have increased long-term hospital use for nervous system diseases. Design A population-based retrospective cohort study using linked administrative health data from the Western Australian Data Linkage System. Participants Records of 30 997 persons hospitalised for a first burn injury in Western Australia during the period 1980–2012, and 123 399 persons who were age and gender frequency matched with no injury admissions randomly selected from Western Australia's birth registrations and electoral roll. Main outcome measures Admission rates and summed length of stay for nervous system diseases. Negative binomial and Cox proportional hazards regression modelling were used to generate incidence rate ratios (IRRs) and HRs with 95% CIs, respectively. Results After adjustment for demographic factors and pre-existing health status, the burn injury cohort had 2.20 times (95% CI 1.86 to 2.61) as many nervous system admissions and 3.25 times the number of days in hospital (95% CI: 2.28 to 4.64) than the uninjured cohort. This increase was found for those who had sustained burns during childhood (<15 years: IRR, 95% CI: 1.97, 1.49 to 2.61) and early to mid-adulthood (15–45 years: IRR, 95% CI: 2.70, 2.06 to 3.55) and older adults (≥45 years: IRR, 95% CI: 1.62, 1.33 to 1.97). Significantly elevated first-time postburn admissions were observed for children for 15 years postburn discharge (0–5 years: HR, 95% CI: 1.97, 1.75 to 2.22; 5–15 years: HR, 95% CI: 1.44, 1.28 to 1.63) and for adults 45 years and older at index burn for 5 years postburn only (HR, 95% CI: 1.72, 1.42 to 2.09). Conclusions Burn injury appears to be associated with increased nervous system-related morbidity for many years after burn injury. Further work into the mechanisms and possible treatments to reduce this morbidity are warranted in light of these findings. PMID:27609857

  12. Long term trends in prevalence of neural tube defects in Europe: population based study

    PubMed Central

    Loane, Maria; de Walle, Hermien; Arriola, Larraitz; Addor, Marie-Claude; Barisic, Ingeborg; Beres, Judit; Bianchi, Fabrizio; Dias, Carlos; Draper, Elizabeth; Garne, Ester; Gatt, Miriam; Haeusler, Martin; Klungsoyr, Kari; Latos-Bielenska, Anna; Lynch, Catherine; McDonnell, Bob; Nelen, Vera; Neville, Amanda J; O’Mahony, Mary T; Queisser-Luft, Annette; Rankin, Judith; Rissmann, Anke; Ritvanen, Annukka; Rounding, Catherine; Sipek, Antonin; Tucker, David; Verellen-Dumoulin, Christine; Wellesley, Diana; Dolk, Helen

    2015-01-01

    Study question What are the long term trends in the total (live births, fetal deaths, and terminations of pregnancy for fetal anomaly) and live birth prevalence of neural tube defects (NTD) in Europe, where many countries have issued recommendations for folic acid supplementation but a policy for mandatory folic acid fortification of food does not exist? Methods This was a population based, observational study using data on 11 353 cases of NTD not associated with chromosomal anomalies, including 4162 cases of anencephaly and 5776 cases of spina bifida from 28 EUROCAT (European Surveillance of Congenital Anomalies) registries covering approximately 12.5 million births in 19 countries between 1991 and 2011. The main outcome measures were total and live birth prevalence of NTD, as well as anencephaly and spina bifida, with time trends analysed using random effects Poisson regression models to account for heterogeneities across registries and splines to model non-linear time trends. Summary answer and limitations Overall, the pooled total prevalence of NTD during the study period was 9.1 per 10 000 births. Prevalence of NTD fluctuated slightly but without an obvious downward trend, with the final estimate of the pooled total prevalence of NTD in 2011 similar to that in 1991. Estimates from Poisson models that took registry heterogeneities into account showed an annual increase of 4% (prevalence ratio 1.04, 95% confidence interval 1.01 to 1.07) in 1995-99 and a decrease of 3% per year in 1999-2003 (0.97, 0.95 to 0.99), with stable rates thereafter. The trend patterns for anencephaly and spina bifida were similar, but neither anomaly decreased substantially over time. The live birth prevalence of NTD generally decreased, especially for anencephaly. Registration problems or other data artefacts cannot be excluded as a partial explanation of the observed trends (or lack thereof) in the prevalence of NTD. What this study adds In the absence of mandatory fortification

  13. Evidence for the impact of global warming on the long-term population dynamics of common birds.

    PubMed

    Julliard, Romain; Jiguet, Frédéric; Couvet, Denis

    2004-12-01

    Taking the opportunity in 2003 of the exceptionally warm spring in France as a natural simulation of possible future climate, we analysed common bird productivity using the French long-term capture-recapture national monitoring scheme. Two-thirds of the 32 species studied had an above-average productivity in 2003. However, this gain in productivity was not consistent among species, with a relatively low productivity for species exhibiting a long-term decline and relatively high productivity for stable or increasing species. Such links between long-term and short-term dynamics suggest that the impact of increasingly warm springs on productivity is a major component of the recent population dynamics of a variety of common bird species.

  14. [The genetic history of long-term Russian resident populations of polar northeastern Siberia based on mitochondrial DNA variability].

    PubMed

    Sukernik, R I; Volod'ko, N V; Mazunin, I O; El'tsov, N P; Starikovskaia, E B

    2010-11-01

    The mtDNA variation has been studied in representatives of the Russkoe Ust'e (n = 30), Kolyma (n = 31), and Markovo (n = 26) ethnic subgroups originating from Russian military men, hunters, and fishers who married local Yukaghir women and settled at the Arctic Ocean coast and on the Anadyr' River more than 350 years ago. The mtDNA haplotypes characteristic of indigenous Siberian peoples have been demonstrated to form the basis of the mitochondrial gene pool of long-term Russian resident populations of the region. Only one of 30 identified haplotypes belonging to 11 haplogroups (H2a) is characteristic of European populations. The C and D haplogroups are the most diverse. The analysis has revealed the characteristics of the population structure of the long-term Russian resident populations and allowed them to be interpreted in terms of recent historical and environmental processes.

  15. Stochastic models of population extinction.

    PubMed

    Ovaskainen, Otso; Meerson, Baruch

    2010-11-01

    Theoretical ecologists have long sought to understand how the persistence of populations depends on biotic and abiotic factors. Classical work showed that demographic stochasticity causes the mean time to extinction to increase exponentially with population size, whereas variation in environmental conditions can lead to a power-law scaling. Recent work has focused especially on the influence of the autocorrelation structure ('color') of environmental noise. In theoretical physics, there is a burst of research activity in analyzing large fluctuations in stochastic population dynamics. This research provides powerful tools for determining extinction times and characterizing the pathway to extinction. It yields, therefore, sharp insights into extinction processes and has great potential for further applications in theoretical biology.

  16. Long-term follow-up of endoscopic third ventriculostomy performed in the pediatric population.

    PubMed

    Stovell, Matthew G; Zakaria, Rasheed; Ellenbogen, Jonathan R; Gallagher, Mathew J; Jenkinson, Michael D; Hayhurst, Caroline; Mallucci, Conor L

    2016-06-01

    OBJECTIVE Endoscopic third ventriculostomy (ETV) is an effective treatment for obstructive hydrocephalus and avoids the risk for foreign-body infection associated with ventriculoperitoneal (VP) shunts. The short-term failure rate of ETV strongly depends on the indications for its use but is generally thought to be lower in the long term than that of VP shunts. However, few studies are available with long-term follow-up data of ETV for hydrocephalus in children. The authors reviewed the long-term success of ETV at their institution to investigate the rate of any late failures of this procedure. METHODS Between April 1998 and June 2006, 113 children (including neonates and children up to 16 years old) had primary or secondary ETV for different causes of hydrocephalus. The patients' medical records and the authors' electronic operation database were reviewed for evidence of additional surgery (i.e., repeat ETV or VP shunt insertion). These records were checked at both the pediatric and adult neurosurgical hospitals for those patients who had their care transferred to adult services. RESULTS The median length of follow-up was 8.25 years (range 1 month to 16 years). Long-term follow-up data for 96 patients were available, 47 (49%) of whom had additional ETV or VP shunt insertion for ETV failure. Twenty patients (21%) had a second procedure within 1 month, 17 patients (18%) between 1 and 12 months, 7 patients (7%) between 1 and 5 years, and 3 patients (3%) between 5 and 8 years. CONCLUSIONS In the authors' series, ETV had an initial early failure rate for the treatment of pediatric hydrocephalus as reported previously, and this rate significantly depended on patient age and hydrocephalus etiology. Once stabilized and effective, ETV appeared to be durable but not guaranteed, and some late decline in effectiveness was observed, with some ETV failures occurring many years later. Thus, successful ETV in children cannot be guaranteed for life, and some form of follow-up is

  17. Long-term transients and complex dynamics of a stage-structured population with time delay and the Allee effect.

    PubMed

    Morozov, A Yu; Banerjee, M; Petrovskii, S V

    2016-05-01

    Traditionally, mathematical modeling in population ecology is mainly focused on asymptotic behavior of the model, i.e. as given by the system attractors. Recently, however, transient regimes and especially long-term transients have been recognized as playing a crucial role in the dynamics of ecosystems. In particular, long-term transients are a potential explanation of ecological regime shifts, when an apparently healthy population suddenly collapses and goes extinct. In this paper, we show that the interplay between delay in maturation and a strong Allee effect can result in long-term transients in a single species system. We first derive a simple 'conceptual' model of the population dynamics that incorporates both a strong Allee effect and maturation delay. Unlike much of the previous work, our approach is not empirical since our model is derived from basic principles. We show that the model exhibits a high complexity in its asymptotic dynamics including multi-periodic and chaotic attractors. We then show the existence of long-term transient dynamics in the system, when the population size oscillates for a long time between locally stable stationary states before it eventually settles either at the persistence equilibrium or goes extinct. The parametric space of the model is found to have a complex structure with the basins of attraction corresponding to the persistence and extinction states being of a complicated shape. This impedes the prediction of the eventual fate of the population, as a small variation in the maturation delay or the initial population size can either bring the population to extinction or ensure its persistence.

  18. A National Population Study of the Co-Occurrence of Multiple Long-Term Conditions in People With Multimorbidity, Denmark, 2013.

    PubMed

    Friis, Karina; Pedersen, Marie Hauge; Larsen, Finn Breinholt; Lasgaard, Mathias

    2016-01-01

    The objective of this study was to describe the prevalence of pairwise combinations of 17 long-term conditions. Data were obtained from a national, representative population-based study including 162,283 Danish citizens aged 16 years or older. We calculated the prevalence of each long-term condition given the presence of another long-term condition. Compared with the general population, people with angina pectoris had more than twice the odds of having 12 of the 16 other long-term conditions, and inversely, people with cancer, tinnitus, or cataracts did not have notably higher odds for any of the other long-term conditions.

  19. A National Population Study of the Co-Occurrence of Multiple Long-Term Conditions in People With Multimorbidity, Denmark, 2013

    PubMed Central

    Pedersen, Marie Hauge; Larsen, Finn Breinholt; Lasgaard, Mathias

    2016-01-01

    The objective of this study was to describe the prevalence of pairwise combinations of 17 long-term conditions. Data were obtained from a national, representative population-based study including 162,283 Danish citizens aged 16 years or older. We calculated the prevalence of each long-term condition given the presence of another long-term condition. Compared with the general population, people with angina pectoris had more than twice the odds of having 12 of the 16 other long-term conditions, and inversely, people with cancer, tinnitus, or cataracts did not have notably higher odds for any of the other long-term conditions. PMID:26820044

  20. Host resistance, population structure and the long-term persistence of bubonic plague: contributions of a modelling approach in the Malagasy focus.

    PubMed

    Gascuel, Fanny; Choisy, Marc; Duplantier, Jean-Marc; Débarre, Florence; Brouat, Carine

    2013-01-01

    Although bubonic plague is an endemic zoonosis in many countries around the world, the factors responsible for the persistence of this highly virulent disease remain poorly known. Classically, the endemic persistence of plague is suspected to be due to the coexistence of plague resistant and plague susceptible rodents in natural foci, and/or to a metapopulation structure of reservoirs. Here, we test separately the effect of each of these factors on the long-term persistence of plague. We analyse the dynamics and equilibria of a model of plague propagation, consistent with plague ecology in Madagascar, a major focus where this disease is endemic since the 1920s in central highlands. By combining deterministic and stochastic analyses of this model, and including sensitivity analyses, we show that (i) endemicity is favoured by intermediate host population sizes, (ii) in large host populations, the presence of resistant rats is sufficient to explain long-term persistence of plague, and (iii) the metapopulation structure of susceptible host populations alone can also account for plague endemicity, thanks to both subdivision and the subsequent reduction in the size of subpopulations, and extinction-recolonization dynamics of the disease. In the light of these results, we suggest scenarios to explain the localized presence of plague in Madagascar.

  1. Bowel, Urinary, and Sexual Problems Among Long-Term Prostate Cancer Survivors: A Population-Based Study

    SciTech Connect

    Mols, Floortje Korfage, Ida J.; Vingerhoets, Ad J.J.M.; Kil, Paul J.M.; Coebergh, Jan Willem W.; Essink-Bot, Marie-Louise; Poll-Franse, Lonneke V. van de

    2009-01-01

    Purpose: To obtain insight into the long-term (5- to 10-year) effects of prostate cancer and treatment on bowel, urinary, and sexual function, we performed a population-based study. Prostate-specific function was compared with an age-matched normative population without prostate cancer. Methods and Materials: Through the population-based Eindhoven Cancer Registry, we selected all men diagnosed with prostate cancer between 1994 and 1998 in the southern Netherlands. In total, 964 patients, alive in November 2004, received questionnaire; 780 (81%) responded. Results: Urinary problems were most common after a prostatectomy; bowel problems were most common after radiotherapy. Compared with an age-matched normative population both urinary and bowel functioning and bother were significantly worse among survivors. Urinary incontinence was reported by 23-48% of survivors compared with 4% of the normative population. Bowel leakage occurred in 5-14% of patients compared with 2% of norms. Erection problems occurred in 40-74% of patients compared with 18% of norms. Conclusions: These results form an important contribution to the limited information available on prostate-specific problems in the growing group of long-term prostate cancer survivors. Bowel, urinary, and sexual problems occur more often among long-term survivors compared with a reference group and cannot be explained merely by age. Because these problems persist for many years, urologists should provide patients with adequate information before treatment. After treatment, there should be an appropriate focus on these problems.

  2. The implications of long term community involvement for the production and circulation of population knowledge

    PubMed Central

    Madhavan, Sangeetha; Collinson, Mark; Townsend, Nicholas W.; Kahn, Kathleen; Tollman, Stephen M.

    2010-01-01

    Demographic surveillance systems (DSS) depend on community acceptance and involvement to produce high quality longitudinal data. Ensuring community support also exposes power relations usually concealed in the research process. We discuss the Agincourt Health and Demographic Surveillance System in South Africa to argue that: 1) long-term presence and community involvement contribute to high response rates and data quality, 2) to maintain community support the project must demonstrate its usefulness, 3) reporting to community members provides valuable checks on the local relevance and comprehension of questions, and 4) community opinion can modify both wording and content of research questions. PMID:20396402

  3. Magnetic Tunnel Junction Based Long-Term Short-Term Stochastic Synapse for a Spiking Neural Network with On-Chip STDP Learning.

    PubMed

    Srinivasan, Gopalakrishnan; Sengupta, Abhronil; Roy, Kaushik

    2016-01-01

    Spiking Neural Networks (SNNs) have emerged as a powerful neuromorphic computing paradigm to carry out classification and recognition tasks. Nevertheless, the general purpose computing platforms and the custom hardware architectures implemented using standard CMOS technology, have been unable to rival the power efficiency of the human brain. Hence, there is a need for novel nanoelectronic devices that can efficiently model the neurons and synapses constituting an SNN. In this work, we propose a heterostructure composed of a Magnetic Tunnel Junction (MTJ) and a heavy metal as a stochastic binary synapse. Synaptic plasticity is achieved by the stochastic switching of the MTJ conductance states, based on the temporal correlation between the spiking activities of the interconnecting neurons. Additionally, we present a significance driven long-term short-term stochastic synapse comprising two unique binary synaptic elements, in order to improve the synaptic learning efficiency. We demonstrate the efficacy of the proposed synaptic configurations and the stochastic learning algorithm on an SNN trained to classify handwritten digits from the MNIST dataset, using a device to system-level simulation framework. The power efficiency of the proposed neuromorphic system stems from the ultra-low programming energy of the spintronic synapses. PMID:27405788

  4. Magnetic Tunnel Junction Based Long-Term Short-Term Stochastic Synapse for a Spiking Neural Network with On-Chip STDP Learning

    PubMed Central

    Srinivasan, Gopalakrishnan; Sengupta, Abhronil; Roy, Kaushik

    2016-01-01

    Spiking Neural Networks (SNNs) have emerged as a powerful neuromorphic computing paradigm to carry out classification and recognition tasks. Nevertheless, the general purpose computing platforms and the custom hardware architectures implemented using standard CMOS technology, have been unable to rival the power efficiency of the human brain. Hence, there is a need for novel nanoelectronic devices that can efficiently model the neurons and synapses constituting an SNN. In this work, we propose a heterostructure composed of a Magnetic Tunnel Junction (MTJ) and a heavy metal as a stochastic binary synapse. Synaptic plasticity is achieved by the stochastic switching of the MTJ conductance states, based on the temporal correlation between the spiking activities of the interconnecting neurons. Additionally, we present a significance driven long-term short-term stochastic synapse comprising two unique binary synaptic elements, in order to improve the synaptic learning efficiency. We demonstrate the efficacy of the proposed synaptic configurations and the stochastic learning algorithm on an SNN trained to classify handwritten digits from the MNIST dataset, using a device to system-level simulation framework. The power efficiency of the proposed neuromorphic system stems from the ultra-low programming energy of the spintronic synapses. PMID:27405788

  5. Magnetic Tunnel Junction Based Long-Term Short-Term Stochastic Synapse for a Spiking Neural Network with On-Chip STDP Learning

    NASA Astrophysics Data System (ADS)

    Srinivasan, Gopalakrishnan; Sengupta, Abhronil; Roy, Kaushik

    2016-07-01

    Spiking Neural Networks (SNNs) have emerged as a powerful neuromorphic computing paradigm to carry out classification and recognition tasks. Nevertheless, the general purpose computing platforms and the custom hardware architectures implemented using standard CMOS technology, have been unable to rival the power efficiency of the human brain. Hence, there is a need for novel nanoelectronic devices that can efficiently model the neurons and synapses constituting an SNN. In this work, we propose a heterostructure composed of a Magnetic Tunnel Junction (MTJ) and a heavy metal as a stochastic binary synapse. Synaptic plasticity is achieved by the stochastic switching of the MTJ conductance states, based on the temporal correlation between the spiking activities of the interconnecting neurons. Additionally, we present a significance driven long-term short-term stochastic synapse comprising two unique binary synaptic elements, in order to improve the synaptic learning efficiency. We demonstrate the efficacy of the proposed synaptic configurations and the stochastic learning algorithm on an SNN trained to classify handwritten digits from the MNIST dataset, using a device to system-level simulation framework. The power efficiency of the proposed neuromorphic system stems from the ultra-low programming energy of the spintronic synapses.

  6. China’s Rapidly Aging Population Creates Policy Challenges In Shaping A Viable Long-Term Care System

    PubMed Central

    Feng, Zhanlian; Liu, Chang; Guan, Xinping; Mor, Vincent

    2013-01-01

    In China, formal long-term care services for the large aging population have increased to meet escalating demands as demographic shifts and socioeconomic changes have eroded traditional elder care. We analyze China’s evolving long-term care landscape and trace major government policies and private-sector initiatives shaping it. Although home and community-based services remain spotty, institutional care is booming with little regulatory oversight. Chinese policy makers face mounting challenges overseeing the rapidly growing residential care sector, given the tension arising from policy inducements to further institutional growth, a weak regulatory framework, and the lack of enforcement capacity. We recommend addressing the following pressing policy issues: building a balanced system of services and avoiding an “institutional bias” that promotes rapid growth of elder care institutions over home or community-based care; strengthening regulatory oversight and quality assurance with information systems; and prioritizing education and training initiatives to grow a professionalized long-term care workforce. PMID:23213161

  7. Long-Term Trends and Role of Climate in the Population Dynamics of Eurasian Reindeer.

    PubMed

    Uboni, Alessia; Horstkotte, Tim; Kaarlejärvi, Elina; Sévêque, Anthony; Stammler, Florian; Olofsson, Johan; Forbes, Bruce C; Moen, Jon

    2016-01-01

    Temperature is increasing in Arctic and sub-Arctic regions at a higher rate than anywhere else in the world. The frequency and nature of precipitation events are also predicted to change in the future. These changes in climate are expected, together with increasing human pressures, to have significant impacts on Arctic and sub-Arctic species and ecosystems. Due to the key role that reindeer play in those ecosystems, it is essential to understand how climate will affect the region's most important species. Our study assesses the role of climate on the dynamics of fourteen Eurasian reindeer (Rangifer tarandus) populations, using for the first time data on reindeer abundance collected over a 70-year period, including both wild and semi-domesticated reindeer, and covering more than half of the species' total range. We analyzed trends in population dynamics, investigated synchrony among population growth rates, and assessed the effects of climate on population growth rates. Trends in the population dynamics were remarkably heterogeneous. Synchrony was apparent only among some populations and was not correlated with distance among population ranges. Proxies of climate variability mostly failed to explain population growth rates and synchrony. For both wild and semi-domesticated populations, local weather, biotic pressures, loss of habitat and human disturbances appear to have been more important drivers of reindeer population dynamics than climate. In semi-domesticated populations, management strategies may have masked the effects of climate. Conservation efforts should aim to mitigate human disturbances, which could exacerbate the potentially negative effects of climate change on reindeer populations in the future. Special protection and support should be granted to those semi-domesticated populations that suffered the most because of the collapse of the Soviet Union, in order to protect the livelihood of indigenous peoples that depend on the species, and the multi

  8. Long-Term Trends and Role of Climate in the Population Dynamics of Eurasian Reindeer.

    PubMed

    Uboni, Alessia; Horstkotte, Tim; Kaarlejärvi, Elina; Sévêque, Anthony; Stammler, Florian; Olofsson, Johan; Forbes, Bruce C; Moen, Jon

    2016-01-01

    Temperature is increasing in Arctic and sub-Arctic regions at a higher rate than anywhere else in the world. The frequency and nature of precipitation events are also predicted to change in the future. These changes in climate are expected, together with increasing human pressures, to have significant impacts on Arctic and sub-Arctic species and ecosystems. Due to the key role that reindeer play in those ecosystems, it is essential to understand how climate will affect the region's most important species. Our study assesses the role of climate on the dynamics of fourteen Eurasian reindeer (Rangifer tarandus) populations, using for the first time data on reindeer abundance collected over a 70-year period, including both wild and semi-domesticated reindeer, and covering more than half of the species' total range. We analyzed trends in population dynamics, investigated synchrony among population growth rates, and assessed the effects of climate on population growth rates. Trends in the population dynamics were remarkably heterogeneous. Synchrony was apparent only among some populations and was not correlated with distance among population ranges. Proxies of climate variability mostly failed to explain population growth rates and synchrony. For both wild and semi-domesticated populations, local weather, biotic pressures, loss of habitat and human disturbances appear to have been more important drivers of reindeer population dynamics than climate. In semi-domesticated populations, management strategies may have masked the effects of climate. Conservation efforts should aim to mitigate human disturbances, which could exacerbate the potentially negative effects of climate change on reindeer populations in the future. Special protection and support should be granted to those semi-domesticated populations that suffered the most because of the collapse of the Soviet Union, in order to protect the livelihood of indigenous peoples that depend on the species, and the multi

  9. Long-Term Trends and Role of Climate in the Population Dynamics of Eurasian Reindeer

    PubMed Central

    Horstkotte, Tim; Kaarlejärvi, Elina; Sévêque, Anthony; Stammler, Florian; Olofsson, Johan; Forbes, Bruce C.; Moen, Jon

    2016-01-01

    Temperature is increasing in Arctic and sub-Arctic regions at a higher rate than anywhere else in the world. The frequency and nature of precipitation events are also predicted to change in the future. These changes in climate are expected, together with increasing human pressures, to have significant impacts on Arctic and sub-Arctic species and ecosystems. Due to the key role that reindeer play in those ecosystems, it is essential to understand how climate will affect the region’s most important species. Our study assesses the role of climate on the dynamics of fourteen Eurasian reindeer (Rangifer tarandus) populations, using for the first time data on reindeer abundance collected over a 70-year period, including both wild and semi-domesticated reindeer, and covering more than half of the species’ total range. We analyzed trends in population dynamics, investigated synchrony among population growth rates, and assessed the effects of climate on population growth rates. Trends in the population dynamics were remarkably heterogeneous. Synchrony was apparent only among some populations and was not correlated with distance among population ranges. Proxies of climate variability mostly failed to explain population growth rates and synchrony. For both wild and semi-domesticated populations, local weather, biotic pressures, loss of habitat and human disturbances appear to have been more important drivers of reindeer population dynamics than climate. In semi-domesticated populations, management strategies may have masked the effects of climate. Conservation efforts should aim to mitigate human disturbances, which could exacerbate the potentially negative effects of climate change on reindeer populations in the future. Special protection and support should be granted to those semi-domesticated populations that suffered the most because of the collapse of the Soviet Union, in order to protect the livelihood of indigenous peoples that depend on the species, and the multi

  10. Short and long term neuro-behavioral alterations in type 1 diabetes mellitus pediatric population.

    PubMed

    Litmanovitch, Edna; Geva, Ronny; Rachmiel, Marianna

    2015-03-15

    Type 1 diabetes mellitus (T1DM) is one of the most prevalent chronic conditions affecting individuals under the age of 18 years, with increasing incidence worldwide, especially among very young age groups, younger than 5. There is still no cure for the disease, and therapeutic goals and guidelines are a challenge. Currently, despite T1DM intensive management and technological interventions in therapy, the majority of pediatric patients do not achieve glycemic control goals. This leads to a potential prognosis of long term diabetic complications, nephrological, cardiac, ophthalmological and neurological. Unfortunately, the neurological manifestations, including neurocognitive and behavioral complications, may present soon after disease onset, during childhood and adolescence. These manifestations may be prominent, but at times subtle, thus they are often not reported by patients or physicians as related to the diabetes. Furthermore, the metabolic mechanism for such manifestations has been inconsistent and difficult to interpret in practical clinical care, as reported in several reviews on the topic of brain and T1DM. However, new technological methods for brain assessment, as well as the introduction of continuous glucose monitoring, provide new insights and information regarding brain related manifestations and glycemic variability and control parameters, which may impact the clinical care of children and youth with T1DM. This paper provides a comprehensive review of the most recently reported behavioral, cognitive domains, sleep related, electrophysiological, and structural alterations in children and adolescences from a novel point of view. The review focuses on reported impairments based on duration of T1DM, its timeline, and modifiable disease related risk parameters. These findings are not without controversy, and limitations of data are presented in addition to recommendations for future research direction. PMID:25789107

  11. Short and long term neuro-behavioral alterations in type 1 diabetes mellitus pediatric population.

    PubMed

    Litmanovitch, Edna; Geva, Ronny; Rachmiel, Marianna

    2015-03-15

    Type 1 diabetes mellitus (T1DM) is one of the most prevalent chronic conditions affecting individuals under the age of 18 years, with increasing incidence worldwide, especially among very young age groups, younger than 5. There is still no cure for the disease, and therapeutic goals and guidelines are a challenge. Currently, despite T1DM intensive management and technological interventions in therapy, the majority of pediatric patients do not achieve glycemic control goals. This leads to a potential prognosis of long term diabetic complications, nephrological, cardiac, ophthalmological and neurological. Unfortunately, the neurological manifestations, including neurocognitive and behavioral complications, may present soon after disease onset, during childhood and adolescence. These manifestations may be prominent, but at times subtle, thus they are often not reported by patients or physicians as related to the diabetes. Furthermore, the metabolic mechanism for such manifestations has been inconsistent and difficult to interpret in practical clinical care, as reported in several reviews on the topic of brain and T1DM. However, new technological methods for brain assessment, as well as the introduction of continuous glucose monitoring, provide new insights and information regarding brain related manifestations and glycemic variability and control parameters, which may impact the clinical care of children and youth with T1DM. This paper provides a comprehensive review of the most recently reported behavioral, cognitive domains, sleep related, electrophysiological, and structural alterations in children and adolescences from a novel point of view. The review focuses on reported impairments based on duration of T1DM, its timeline, and modifiable disease related risk parameters. These findings are not without controversy, and limitations of data are presented in addition to recommendations for future research direction.

  12. Modelling cadmium contamination in paddy soils under long-term remediation measures: Model development and stochastic simulations.

    PubMed

    Peng, Chi; Wang, Meie; Chen, Weiping

    2016-09-01

    A pollutant accumulation model (PAM) based on the mass balance theory was developed to simulate long-term changes of heavy metal concentrations in soil. When combined with Monte Carlo simulation, the model can predict the probability distributions of heavy metals in a soil-water-plant system with fluctuating environmental parameters and inputs from multiple pathways. The model was used for evaluating different remediation measures to deal with Cd contamination of paddy soils in Youxian county (Hunan province), China, under five scenarios, namely the default scenario (A), not returning paddy straw to the soil (B), reducing the deposition of Cd (C), liming (D), and integrating several remediation measures (E). The model predicted that the Cd contents of soil can lowered significantly by (B) and those of the plants by (D). However, in the long run, (D) will increase soil Cd. The concentrations of Cd in both soils and rice grains can be effectively reduced by (E), although it will take decades of effort. The history of Cd pollution and the major causes of Cd accumulation in soil were studied by means of sensitivity analysis and retrospective simulation. PMID:27257714

  13. Long-term monitoring of endangered Laysan ducks: Index validation and population estimates 1998–2012

    USGS Publications Warehouse

    Reynolds, Michelle H.; Courtot, Karen; Brinck, Kevin W.; Rehkemper, Cynthia; Hatfield, Jeffrey

    2015-01-01

    Monitoring endangered wildlife is essential to assessing management or recovery objectives and learning about population status. We tested assumptions of a population index for endangered Laysan duck (or teal; Anas laysanensis) monitored using mark–resight methods on Laysan Island, Hawai’i. We marked 723 Laysan ducks between 1998 and 2009 and identified seasonal surveys through 2012 that met accuracy and precision criteria for estimating population abundance. Our results provide a 15-y time series of seasonal population estimates at Laysan Island. We found differences in detection among seasons and how observed counts related to population estimates. The highest counts and the strongest relationship between count and population estimates occurred in autumn (September–November). The best autumn surveys yielded population abundance estimates that ranged from 674 (95% CI = 619–730) in 2003 to 339 (95% CI = 265–413) in 2012. A population decline of 42% was observed between 2010 and 2012 after consecutive storms and Japan’s To¯hoku earthquake-generated tsunami in 2011. Our results show positive correlations between the seasonal maximum counts and population estimates from the same date, and support the use of standardized bimonthly counts of unmarked birds as a valid index to monitor trends among years within a season at Laysan Island.

  14. The effect of long-term migration dynamics on population structure in England & Wales and Scotland.

    PubMed

    Murphy, Michael

    2016-07-01

    We investigated the effect of migration on population dynamics in England & Wales and Scotland from the mid-nineteenth century to the present by comparing actual population size and structure with estimates based on zero net migration from a range of starting dates. In this period, Scotland had the largest net outflow among countries in Europe for which detailed information is available, whereas overall net migration in England & Wales was close to zero. In the absence of migration, population would have been over twice as large in Scotland in 2013 as the actual value, but similar to its actual value in England & Wales. Levels and pace of population ageing have been broadly similar in both countries, so the major impact of differential migration has been on population size rather than structure. We discuss these findings in relation to the debate on migration policy between political parties supporting and opposing independence in the 2014 Scottish referendum. PMID:27294474

  15. Police use of handcuffs in the homeless population leads to long-term negative attitudes within this group.

    PubMed

    Krameddine, Yasmeen I; Silverstone, Peter H

    2016-01-01

    The police interact with homeless individuals frequently. However, there has been relatively little research on the attitudes of homeless individuals towards the police, and how police interactions may impact these. This is important since the attitudes of homeless individuals can impact how often they report crimes, and how well they support police when they are investigating crimes in this population. We interviewed 213 homeless individuals in a single city, representing approximately 10% of the total homeless population. They were interviewed at either homeless shelters, or events held specifically for the homeless population. Of these individuals, 75% were male, and 47% had interacted with a police officer within the past month. Self-reports suggested that 60% had a drug and/or alcohol issue and 78% had a mental illness. We found a highly statistically significant difference between the group that had been handcuffed and/or arrested compared to those that had not. This was across multiple domains and included how the individual regarded the police in terms of their empathy and communication skills, and how much they trusted the police. These changes were long-term, and if a homeless individual had been arrested or handcuffed (and verbal reporting suggested that being handcuffed was the by far the most important factor) then these negative attitudes lasted at least 2 years. The primary conclusion from this study is that when police handcuff a homeless individual, this can lead to long-term negative views about the police across several domains that appear to be long lasting, and were linked to feelings of not being respected by the police. It is therefore proposed that police officers should be made aware of the potential long-term negative consequences of this single action, and that police forces should consider providing specific training to minimize any unnecessary overuse of handcuffs.

  16. The Long Term Recovery of New Orleans’ Population after Hurricane Katrina

    PubMed Central

    Fussell, Elizabeth

    2015-01-01

    Hurricane Katrina created a catastrophe in the city of New Orleans when the storm surge caused the levee system to fail on August 29, 2005. The destruction of housing displaced hundreds of thousands of residents for varying lengths of time, often permanently. It also revealed gaps in our knowledge of how population is recovered after a disaster causes widespread destruction of urban infrastructure, housing and workplaces, and how mechanisms driving housing recovery often produce unequal social, spatial and temporal population recovery. In this article, I assemble social, spatial and temporal explanatory frameworks for housing and population recovery and then review research on mobility – both evacuation and migration – after Hurricane Katrina. The review reveals a need for a comprehensive social, spatial and temporal framework for explaining inequality in population recovery and displacement. It also shows how little is known about in-migrants and permanent out-migrants after a disaster. PMID:26880853

  17. Long-term changes in Serengeti-Mara wildebeest and land cover: Pastoralism, population, or policies?

    PubMed Central

    Homewood, K.; Lambin, E. F.; Coast, E.; Kariuki, A.; Kikula, I.; Kivelia, J.; Said, M.; Serneels, S.; Thompson, M.

    2001-01-01

    Declines in habitat and wildlife in semiarid African savannas are widely reported and commonly attributed to agropastoral population growth, livestock impacts, and subsistence cultivation. However, extreme annual and shorter-term variability of rainfall, primary production, vegetation, and populations of grazers make directional trends and causal chains hard to establish in these ecosystems. Here two decades of changes in land cover and wildebeest in the Serengeti-Mara region of East Africa are analyzed in terms of potential drivers (rainfall, human and livestock population growth, socio-economic trends, land tenure, agricultural policies, and markets). The natural experiment research design controls for confounding variables, and our conceptual model and statistical approach integrate natural and social sciences data. The Kenyan part of the ecosystem shows rapid land-cover change and drastic decline for a wide range of wildlife species, but these changes are absent on the Tanzanian side. Temporal climate trends, human population density and growth rates, uptake of small-holder agriculture, and livestock population trends do not differ between the Kenyan and Tanzanian parts of the ecosystem and cannot account for observed changes. Differences in private versus state/communal land tenure, agricultural policy, and market conditions suggest, and spatial correlations confirm, that the major changes in land cover and dominant grazer species numbers are driven primarily by private landowners responding to market opportunities for mechanized agriculture, less by agropastoral population growth, cattle numbers, or small-holder land use. PMID:11675492

  18. Population dynamics of Meloidogyne arenaria and Pasteuria penetrans in a long-term crop rotation study.

    PubMed

    Timper, Patricia

    2009-12-01

    The endospore-forming bacterium Pasteuria penetrans is an obligate parasite of root-knot nematodes (Meloidogyne spp.). The primary objective of this study was to determine the effect of crop sequence on abundance of P. penetrans. The experiment was conducted from 2000 to 2008 at a field site naturally infested with both the bacterium and its host Meloidogyne arenaria and included the following crop sequences: continuous peanut (Arachis hypogaea) (P-P-P) and peanut rotated with either 2 years of corn (Zea mays) (C-C-P), 1 year each of cotton (Gossypium hirsutum) and corn (Ct-C-P), or 1 year each of corn and a vegetable (V-C-P). The vegetable was a double crop of sweet corn and eggplant (Solanum melongena). A bioassay with second-stage juveniles (J2) of M. arenaria from a greenhouse (GH) population was used to estimate endospore abundance under the different crop sequences. A greater numerical increase in endospore densities was expected in the P-P-P and V-C-P sequences than in the other sequences because both peanut and eggplant are good hosts for M. arenaria. However, endospore densities, as determined by bioassay, did not substantially increase in any of the sequences during the 9-year experiment. To determine whether the nematode population had developed resistance to the resident P. penetrans, five single egg-mass (SEM) lines from the field population of M. arenaria were tested alongside the GH population for acquisition of endospores from the field soil. Four of the five SEM lines acquired 9 to 14 spores/J2 whereas the GH population and one of the SEM lines acquired 3.5 and 1.8 spores/J2, respectively. Endospore densities estimated with the four receptive SEM lines were highest in the P-P-P plots (14-20 spores/J2), intermediate in the V-C-P plots (6-7 spores/J2), and lowest in the Ct-C-P plots (< 1 spore/J2). These results indicate that the field population of M. arenaria is heterogeneous for attachment of P. penetrans endospores. Moreover, spore densities

  19. Estimating the long-term historic evolution of exposure to flooding of coastal populations

    NASA Astrophysics Data System (ADS)

    Stevens, A. J.; Clarke, D.; Nicholls, R. J.; Wadey, M. P.

    2015-02-01

    Coastal managers face the task of assessing and managing flood risk. This requires knowledge of the area of land, the number of people, properties and other infrastructure potentially affected by floods. Such analyses are usually static; i.e. they only consider a snapshot of the current situation. This misses the opportunity to learn about the role of key drivers of historical changes in flood risk, such as development and population rise in the coastal flood plain and sea-level rise. In this paper, we develop and apply a method to analyse the temporal evolution of residential population exposure to coastal flooding. It uses readily available data in a GIS environment. We examine how population and sea level change modify exposure over two centuries in two neighbouring coastal sites: Portsea and Hayling Islands on the UK south coast. The analysis shows that flood exposure changes as a result of increases in population, changes in coastal population density and sea level rise. The results indicate that to date, population change is the dominant driver of the increase in exposure to flooding in the study sites, but climate change may outweigh this in the future. A full analysis of flood risk is not possible as data on historic defences and wider vulnerability are not available. Hence, the historic evolution of flood exposure is as close as we can get to a historic evolution of flood risk. The method is applicable anywhere that suitable floodplain geometry, sea level and population datasets are available and could be widely applied, and will help inform coastal managers of the time evolution in coastal flood drivers.

  20. Estimating the long-term historic evolution of exposure to flooding of coastal populations

    NASA Astrophysics Data System (ADS)

    Stevens, A. J.; Clarke, D.; Nicholls, R. J.; Wadey, M. P.

    2015-06-01

    Coastal managers face the task of assessing and managing flood risk. This requires knowledge of the area of land, the number of people, properties and other infrastructure potentially affected by floods. Such analyses are usually static; i.e. they only consider a snapshot of the current situation. This misses the opportunity to learn about the role of key drivers of historical changes in flood risk, such as development and population rise in the coastal flood plain, as well as sea-level rise. In this paper, we develop and apply a method to analyse the temporal evolution of residential population exposure to coastal flooding. It uses readily available data in a GIS environment. We examine how population and sea-level change have modified exposure over two centuries in two neighbouring coastal sites: Portsea and Hayling Islands on the UK south coast. The analysis shows that flood exposure changes as a result of increases in population, changes in coastal population density and sea level rise. The results indicate that to date, population change is the dominant driver of the increase in exposure to flooding in the study sites, but climate change may outweigh this in the future. A full analysis of changing flood risk is not possible as data on historic defences and wider vulnerability are not available. Hence, the historic evolution of flood exposure is as close as we can get to a historic evolution of flood risk. The method is applicable anywhere that suitable floodplain geometry, sea level and population data sets are available and could be widely applied, and will help inform coastal managers of the time evolution in coastal flood drivers.

  1. Mountain gorilla genomes reveal the impact of long-term population decline and inbreeding.

    PubMed

    Xue, Yali; Prado-Martinez, Javier; Sudmant, Peter H; Narasimhan, Vagheesh; Ayub, Qasim; Szpak, Michal; Frandsen, Peter; Chen, Yuan; Yngvadottir, Bryndis; Cooper, David N; de Manuel, Marc; Hernandez-Rodriguez, Jessica; Lobon, Irene; Siegismund, Hans R; Pagani, Luca; Quail, Michael A; Hvilsom, Christina; Mudakikwa, Antoine; Eichler, Evan E; Cranfield, Michael R; Marques-Bonet, Tomas; Tyler-Smith, Chris; Scally, Aylwyn

    2015-04-10

    Mountain gorillas are an endangered great ape subspecies and a prominent focus for conservation, yet we know little about their genomic diversity and evolutionary past. We sequenced whole genomes from multiple wild individuals and compared the genomes of all four Gorilla subspecies. We found that the two eastern subspecies have experienced a prolonged population decline over the past 100,000 years, resulting in very low genetic diversity and an increased overall burden of deleterious variation. A further recent decline in the mountain gorilla population has led to extensive inbreeding, such that individuals are typically homozygous at 34% of their sequence, leading to the purging of severely deleterious recessive mutations from the population. We discuss the causes of their decline and the consequences for their future survival.

  2. Long-term observation of amphibian populations inhabiting urban and forested areas in Yekaterinburg, Russia

    PubMed Central

    Vershinin, Vladimir L.; Vershinina, Svetlana D.; Berzin, Dmitry L.; Zmeeva, Darya V.; Kinev, Alexander V.

    2015-01-01

    This article presents data derived from a 36 year-long uninterrupted observational study of amphibian populations living in the city and vicinity of Yekaterinburg, Russia. This area is inhabited by six amphibian species. Based on a degree of anthropogenic transformation, the urban territory is divided into five highly mosaic zones characterized by vegetation, temperature, and a distinctive water pollution profile. Population data is presented year-by-year for the number of animals, sex ratio, and species-specific fecundity including the number and quality of spawns for the following amphibian species: Salamandrella keyserligii, Rana arvalis, R. temporaria, Lissotriton vulgaris, and Pelophylax ridibundus. These data provide an excellent opportunity to assess an urban environment from an animal population-wide perspective, as well as revealing the forces driving animal adaptation to the anthropogenic transformation of habitats. PMID:25984350

  3. Long-term variation of fiddler crab populations in North Carolina salt marshes

    SciTech Connect

    Cammen, L.M.; Seneca, E.D.; Stroud, L.M.

    1984-06-01

    As part of the environmental monitoring of possible effects of the Brunswick nuclear power plant fiddle crab populations were sampled in several salt marshes in the lower Cape Fear River estuary, North Carolina for five years. Total biomass of the fiddler crabs Uca Pugnax and U. minax in four Spartina marshes declined by 65 to 70% between the summers of 1974-1975 and 1976-1977 with no significant decrease in population density; there was evidence of a recovery in summer of 1978 to the 1974-1975 levels. The cause of these fluctuations is unknown, but such a degree of variability in intertidal populations emphasizes the need for caution in using one or two-year baseline studies to evalute potential environmental impacts. 1 figure, 2 table.

  4. Mountain gorilla genomes reveal the impact of long-term population decline and inbreeding

    PubMed Central

    Ayub, Qasim; Szpak, Michal; Frandsen, Peter; Chen, Yuan; Yngvadottir, Bryndis; Cooper, David N.; de Manuel, Marc; Hernandez-Rodriguez, Jessica; Lobon, Irene; Siegismund, Hans R.; Pagani, Luca; Quail, Michael A.; Hvilsom, Christina; Mudakikwa, Antoine; Eichler, Evan E.; Cranfield, Michael R.; Marques-Bonet, Tomas; Tyler-Smith, Chris; Scally, Aylwyn

    2015-01-01

    Mountain gorillas are an endangered great ape subspecies and a prominent focus for conservation, yet we know little about their genomic diversity and evolutionary past. We sequenced whole genomes from multiple wild individuals and compared the genomes of all four Gorilla subspecies. We found that the two eastern subspecies have experienced a prolonged population decline over the past 100,000 years, resulting in very low genetic diversity and an increased overall burden of deleterious variation. A further recent decline in the mountain gorilla population has led to extensive inbreeding, such that individuals are typically homozygous at 34% of their sequence, leading to the purging of severely deleterious recessive mutations from the population. We discuss the causes of their decline and the consequences for their future survival. PMID:25859046

  5. Long-Term Benefits of Full-Day Kindergarten: A Longitudinal Population-Based Study

    ERIC Educational Resources Information Center

    Brownell, M. D.; Nickel, N. C.; Chateau, D.; Martens, P. J.; Taylor, C.; Crockett, L.; Katz, A.; Sarkar, J.; Burland, E.; Goh, C. Y.

    2015-01-01

    In the first longitudinal, population-based study of full-day kindergarten (FDK) outcomes beyond primary school in Canada, we used linked administrative data to follow 15 kindergarten cohorts (n ranging from 112 to 736) up to grade 9. Provincial assessments conducted in grades 3, 7, and 8 and course marks and credits earned in grade 9 were…

  6. 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 ...

  7. Bacterial populations within copper mine tailings: long-term effects of amendment with Class A biosolids

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This study evaluates the effect of surface application of dried Class A biosolids on microbial populations within copper mine tailings. Methods and Results: Mine tailing sites were established at ASARCO Mission Mine close to Sahuarita, Arizona. Site 1 (Dec. 1998) was amended with 248 tons ha-1 of C...

  8. Improved Analysis of Long-Term Monitoring Data Demonstrates Marked Regional Declines of Bat Populations in the Eastern United States.

    PubMed

    Ingersoll, Thomas E; Sewall, Brent J; Amelon, Sybill K

    2013-01-01

    Bats are diverse and ecologically important, but are also subject to a suite of severe threats. Evidence for localized bat mortality from these threats is well-documented in some cases, but long-term changes in regional populations of bats remain poorly understood. Bat hibernation surveys provide an opportunity to improve understanding, but analysis is complicated by bats' cryptic nature, non-conformity of count data to assumptions of traditional statistical methods, and observation heterogeneities such as variation in survey timing. We used generalized additive mixed models (GAMMs) to account for these complicating factors and to evaluate long-term, regional population trajectories of bats. We focused on four hibernating bat species - little brown myotis (Myotis lucifugus), tri-colored bat (Perimyotis subflavus), Indiana myotis (M. sodalis), and northern myotis (M. septentrionalis) - in a four-state region of the eastern United States during 1999-2011. Our results, from counts of nearly 1.2 million bats, suggest that cumulative declines in regional relative abundance by 2011 from peak levels were 71% (with 95% confidence interval of ±11%) in M. lucifugus, 34% (±38%) in P. subflavus, 30% (±26%) in M. sodalis, and 31% (±18%) in M. septentrionalis. The M. lucifugus population fluctuated until 2004 before persistently declining, and the populations of the other three species declined persistently throughout the study period. Population trajectories suggest declines likely resulted from the combined effect of multiple threats, and indicate a need for enhanced conservation efforts. They provide strong support for a change in the IUCN Red List conservation status in M. lucifugus from Least Concern to Endangered within the study area, and are suggestive of a need to change the conservation status of the other species. Our modeling approach provided estimates of uncertainty, accommodated non-linearities, and controlled for observation heterogeneities, and thus has wide

  9. Long-term population, productivity, and energy use trends in the sequence of leading capitalist nations.

    SciTech Connect

    LePoire, D. J.

    2010-10-01

    There are many theories on why sustainable science, technology, and commerce emerged first in Western Europe rather than elsewhere. A general theory is that the geography of Europe facilitated the development of diverse and independent states and resultant competition among them. Over the past 500 years, the sequence of leading states began with Portugal and the Netherlands on the edge of continental Western Europe, then moved to the British Isles, and finally moved across the Atlantic Ocean to the United States. The transitions of leadership from one state to another occurred about every 100 years. This sequence suggests that leadership moves from smaller states to larger states (although not to the largest existing state at the time), perhaps because larger states have the flexibility to develop more complex organizational processes and adapt new technology. To explore this theory further, this paper analyzes state population data at the beginning and end of each leadership period. The data reveal an accelerating initial population sequence. Further understanding is gained from comparing the populations of the preceding and succeeding states at the time of each transition: the succeeding state's population is usually about two times larger than that of the preceding state. It is also seen that over time, the new organizational processes and technologies developed by the leading state are diffused and adapted by other states. Evidence of the effects of this diffusion should be seen in the dynamics of relative productivity and energy use (since the relative advantage of new ideas and technology can be maintained for a short period of about 100 years). This paper investigates these trends in population, trade, and resources to provide insight on possible future transitions.

  10. On the decline of the Rusty Blackbird and the use of ornithological literature to document long-term population trends

    USGS Publications Warehouse

    Greenberg, R.; Droege, S.

    1999-01-01

    Unlike most North American blackbirds, Rusty Blackbirds (Euphagus carolensis) have shown steep population declines. Declines of approximately 90% are indicated for three recent decades from the Breeding Bird Survey, Christmas Bird Counts, and Quebec Checklist Program. Analyses of abundance classifications in bird distribution books and annotated checklists reveal an overlooked but long-term decline dating back to at least the early part of this century. Rusty Blackbirds were described as very common to abundant in 5656 of the pre-192O published accounts, 19% of the 1921-1950 accounts, and only 7% of the post-1950 accounts. Rusty Blackbirds were described as uncommon in none of the pre-1950 accounts, 18% of the 1951-1980 accounts, and 43% of the post-1980 accounts. A similar pattern was found for analyses based on local checklists. Destruction of wooded wetlands on wintering grounds, acid precipitation, and the conversion of boreal forest wetlands could have contributed to these declines. Systematic analysis of regional guides and checklists provides a valuable tool for examining large-scale and long-term population changes in birds.

  11. Impacts of neonicotinoid use on long-term population changes in wild bees in England

    NASA Astrophysics Data System (ADS)

    Woodcock, Ben A.; Isaac, Nicholas J. B.; Bullock, James M.; Roy, David B.; Garthwaite, David G.; Crowe, Andrew; Pywell, Richard F.

    2016-08-01

    Wild bee declines have been ascribed in part to neonicotinoid insecticides. While short-term laboratory studies on commercially bred species (principally honeybees and bumblebees) have identified sub-lethal effects, there is no strong evidence linking these insecticides to losses of the majority of wild bee species. We relate 18 years of UK national wild bee distribution data for 62 species to amounts of neonicotinoid use in oilseed rape. Using a multi-species dynamic Bayesian occupancy analysis, we find evidence of increased population extinction rates in response to neonicotinoid seed treatment use on oilseed rape. Species foraging on oilseed rape benefit from the cover of this crop, but were on average three times more negatively affected by exposure to neonicotinoids than non-crop foragers. Our results suggest that sub-lethal effects of neonicotinoids could scale up to cause losses of bee biodiversity. Restrictions on neonicotinoid use may reduce population declines.

  12. Impacts of neonicotinoid use on long-term population changes in wild bees in England.

    PubMed

    Woodcock, Ben A; Isaac, Nicholas J B; Bullock, James M; Roy, David B; Garthwaite, David G; Crowe, Andrew; Pywell, Richard F

    2016-08-16

    Wild bee declines have been ascribed in part to neonicotinoid insecticides. While short-term laboratory studies on commercially bred species (principally honeybees and bumblebees) have identified sub-lethal effects, there is no strong evidence linking these insecticides to losses of the majority of wild bee species. We relate 18 years of UK national wild bee distribution data for 62 species to amounts of neonicotinoid use in oilseed rape. Using a multi-species dynamic Bayesian occupancy analysis, we find evidence of increased population extinction rates in response to neonicotinoid seed treatment use on oilseed rape. Species foraging on oilseed rape benefit from the cover of this crop, but were on average three times more negatively affected by exposure to neonicotinoids than non-crop foragers. Our results suggest that sub-lethal effects of neonicotinoids could scale up to cause losses of bee biodiversity. Restrictions on neonicotinoid use may reduce population declines.

  13. Impacts of neonicotinoid use on long-term population changes in wild bees in England

    PubMed Central

    Woodcock, Ben A.; Isaac, Nicholas J. B.; Bullock, James M.; Roy, David B.; Garthwaite, David G.; Crowe, Andrew; Pywell, Richard F.

    2016-01-01

    Wild bee declines have been ascribed in part to neonicotinoid insecticides. While short-term laboratory studies on commercially bred species (principally honeybees and bumblebees) have identified sub-lethal effects, there is no strong evidence linking these insecticides to losses of the majority of wild bee species. We relate 18 years of UK national wild bee distribution data for 62 species to amounts of neonicotinoid use in oilseed rape. Using a multi-species dynamic Bayesian occupancy analysis, we find evidence of increased population extinction rates in response to neonicotinoid seed treatment use on oilseed rape. Species foraging on oilseed rape benefit from the cover of this crop, but were on average three times more negatively affected by exposure to neonicotinoids than non-crop foragers. Our results suggest that sub-lethal effects of neonicotinoids could scale up to cause losses of bee biodiversity. Restrictions on neonicotinoid use may reduce population declines. PMID:27529661

  14. A population approach to mitigating the long-term health effects of combat deployments.

    PubMed

    Reisinger, Heather Schacht; Hunt, Stephen C; Burgo-Black, A Lucile; Agarwal, Madhulika A

    2012-01-01

    A major focus of the mission of the US Department of Veterans Affairs (VA) is to respond to the needs of military personnel returning from war. Given the broad spectrum of the potential effects of combat deployment on the health and well being of service members, VA is increasingly oriented toward comprehensive postcombat support, health promotion, disease prevention, and proactive approaches to caring for combat veterans. This article briefly summarizes the health care needs of service members returning from Afghanistan and Iraq, describes VA's approaches to addressing their needs, and outlines VA's evolving vision for how to apply principles of population health management to ensure prompt and effective response to the postdeployment needs of veterans returning from future conflicts. At the heart of postcombat care will be population-based approaches oriented to health recovery using interdisciplinary, team-based platforms.

  15. Impacts of neonicotinoid use on long-term population changes in wild bees in England.

    PubMed

    Woodcock, Ben A; Isaac, Nicholas J B; Bullock, James M; Roy, David B; Garthwaite, David G; Crowe, Andrew; Pywell, Richard F

    2016-01-01

    Wild bee declines have been ascribed in part to neonicotinoid insecticides. While short-term laboratory studies on commercially bred species (principally honeybees and bumblebees) have identified sub-lethal effects, there is no strong evidence linking these insecticides to losses of the majority of wild bee species. We relate 18 years of UK national wild bee distribution data for 62 species to amounts of neonicotinoid use in oilseed rape. Using a multi-species dynamic Bayesian occupancy analysis, we find evidence of increased population extinction rates in response to neonicotinoid seed treatment use on oilseed rape. Species foraging on oilseed rape benefit from the cover of this crop, but were on average three times more negatively affected by exposure to neonicotinoids than non-crop foragers. Our results suggest that sub-lethal effects of neonicotinoids could scale up to cause losses of bee biodiversity. Restrictions on neonicotinoid use may reduce population declines. PMID:27529661

  16. Long-term population-based marriage rates among adult survivors of childhood cancer in Britain.

    PubMed

    Frobisher, Clare; Lancashire, Emma R; Winter, David L; Jenkinson, Helen C; Hawkins, Michael M

    2007-08-15

    The objectives of this study were to assess the number of adult survivors of childhood cancer who ever married and the factors influencing marriage, compare observed marriages to those expected from the general population, and assess age at marriage and influencing factors. The data is based on the British Childhood Cancer Survivor Study (BCCSS), which is a population-based cohort of 18,119 individuals who were diagnosed with childhood cancer between 1940 and 91 and survived at least 5 years. Fourteen thousand five hundred thirty-nine were alive, aged at least 16 years and eligible to receive a postal questionnaire, which ascertained marriage status. Thirty-four percent of 9,954 survivors had married. Survivors with the following characteristics: males, CNS neoplasm, received radiotherapy, diagnosed with mental retardation, registered blind, low social functioning score (calculated from SF-36 health status measure), and achieved the highest level of educational attainment, were less likely to have married than the complementary survivor groups. The deficits in the proportion ever married compared to the general population were mostly between 9 and 18% among males and 7-10% among females. The largest ever married deficits were among male CNS neoplasm survivors aged 30 years or over (29-38%). Age at first marriage among survivors was related to: sex, childhood cancer type, age at diagnosis, chemotherapy, radiotherapy, mental retardation, and level of educational attainment. Regular follow-up for these survivors should address not just physical late-effects of the childhood cancer and treatment, but also psychosocial needs throughout the lifespan of the survivors to help them achieve life events as they occur in the general population.

  17. Long-term analysis of survival, fertility, and population growth rate of black bears in North Carolina

    USGS Publications Warehouse

    Brongo, L.L.; Mitchell, M.S.; Grand, J.B.

    2005-01-01

    We estimated survival, fertility, and realized and asymptotic population growth rates from 1981 to 2002 for a protected population of black bears (Ursus americanus) in the southern Appalachian Mountains. We used Akaike's information criterion to assess the time interval for averaging observations that was best for estimating vital rates for our study, given our yearly sample sizes. The temporal symmetry approach allowed us to directly assess population growth and to address all losses and gains to the population by using only capture data, offering an alternative to the logistically intensive collection of reproductive data. Models that averaged survival and fertility across 5- and 7-year time intervals were best supported by our data. Studies of black bear populations with annual sample sizes similar to ours should be of at least 5 years in duration to estimate vital rates reliably, and at least 10 years in duration to evaluate changes in population growth rate (??). We also hypothesized that survival would not track changes in ?? because ?? is influenced by both survival and fertility. The 5-year model supported our hypothesis, but the 7-year model did not. Where long-term dynamics of large, relatively stable bear populations are of interest, monitoring survival is likely to be sufficient for evaluating trends in ??. For rapidly changing, small populations, however, failure to incorporate fertility into assessments of ?? could be misleading. ?? 2005 American Society of Mammalogists.

  18. Chronic hepatitis C: treatment, complications, and long-term outcomes in a population of Latino veterans

    PubMed Central

    Santiago-Rolon, Amarilys; Purcell, Dagmary; Grigg, Nicole; Toro, Doris H.

    2016-01-01

    Objectives Chronic hepatitis C (CHC) is a major public health problem in Puerto Rico. It is the most common cause of chronic liver disease and the most frequent indication for liver transplantation in the United States." Our main objectives were to estimate the seroprevalence of CHC infection, to describe the demographic and histological parameters of the infection in our sample population, and to evaluate the treatment outcomes in Puerto Rican veterans. Methods To determine overall seroprevalence, we reviewed all the hepatitis C cases (encompassing from January 1, 2002, to December 31, 2009) of the VA Caribbean Healthcare System, Department of Veterans Affairs. The records of only those individuals who received treatment with pegylated interferon and ribavirin were reviewed to determine risks factors for infection, response rates, adverse events, and outcomes. Results During the study period, there were a total of 1,496 patients identified as being infected with HCV, for an estimated seroprevalence of 2.3%. Of these, approximately 10% (137) were treated with combination therapy and were included in this study. The mean age was 58 (±6.4); 96.4% were men. The most common genotype was type 1. The responses to treatment were generally poor, with only 48.4% of the patients achieving Ssustained virological response. Discussion Though the seroprevalence of chronic hepatitis C in the Latino veteran population of Puerto Rico is high, relatively few patients have received treatment, most probably because of the contraindications of the medications used. Combination therapy with pegylated interferon plus weight-based ribavirin was inefficient and plagued with side effects; as a whole, this therapy was not found to be overly beneficial to our patients. New emerging and approved therapies will change this paradigm, allowing the treatment of a larger population without the side effects of the studied therapy. PMID:26932282

  19. Spatial Analysis of Factors Influencing Long-Term Stress in the Grizzly Bear (Ursus arctos) Population of Alberta, Canada

    PubMed Central

    Bourbonnais, Mathieu L.; Nelson, Trisalyn A.; Cattet, Marc R. L.; Darimont, Chris T.; Stenhouse, Gordon B.

    2013-01-01

    Non-invasive measures for assessing long-term stress in free ranging mammals are an increasingly important approach for understanding physiological responses to landscape conditions. Using a spatially and temporally expansive dataset of hair cortisol concentrations (HCC) generated from a threatened grizzly bear (Ursus arctos) population in Alberta, Canada, we quantified how variables representing habitat conditions and anthropogenic disturbance impact long-term stress in grizzly bears. We characterized spatial variability in male and female HCC point data using kernel density estimation and quantified variable influence on spatial patterns of male and female HCC stress surfaces using random forests. Separate models were developed for regions inside and outside of parks and protected areas to account for substantial differences in anthropogenic activity and disturbance within the study area. Variance explained in the random forest models ranged from 55.34% to 74.96% for males and 58.15% to 68.46% for females. Predicted HCC levels were higher for females compared to males. Generally, high spatially continuous female HCC levels were associated with parks and protected areas while low-to-moderate levels were associated with increased anthropogenic disturbance. In contrast, male HCC levels were low in parks and protected areas and low-to-moderate in areas with increased anthropogenic disturbance. Spatial variability in gender-specific HCC levels reveal that the type and intensity of external stressors are not uniform across the landscape and that male and female grizzly bears may be exposed to, or perceive, potential stressors differently. We suggest observed spatial patterns of long-term stress may be the result of the availability and distribution of foods related to disturbance features, potential sexual segregation in available habitat selection, and may not be influenced by sources of mortality which represent acute traumas. In this wildlife system and others

  20. Spatial analysis of factors influencing long-term stress in the grizzly bear (Ursus arctos) population of Alberta, Canada.

    PubMed

    Bourbonnais, Mathieu L; Nelson, Trisalyn A; Cattet, Marc R L; Darimont, Chris T; Stenhouse, Gordon B

    2013-01-01

    Non-invasive measures for assessing long-term stress in free ranging mammals are an increasingly important approach for understanding physiological responses to landscape conditions. Using a spatially and temporally expansive dataset of hair cortisol concentrations (HCC) generated from a threatened grizzly bear (Ursus arctos) population in Alberta, Canada, we quantified how variables representing habitat conditions and anthropogenic disturbance impact long-term stress in grizzly bears. We characterized spatial variability in male and female HCC point data using kernel density estimation and quantified variable influence on spatial patterns of male and female HCC stress surfaces using random forests. Separate models were developed for regions inside and outside of parks and protected areas to account for substantial differences in anthropogenic activity and disturbance within the study area. Variance explained in the random forest models ranged from 55.34% to 74.96% for males and 58.15% to 68.46% for females. Predicted HCC levels were higher for females compared to males. Generally, high spatially continuous female HCC levels were associated with parks and protected areas while low-to-moderate levels were associated with increased anthropogenic disturbance. In contrast, male HCC levels were low in parks and protected areas and low-to-moderate in areas with increased anthropogenic disturbance. Spatial variability in gender-specific HCC levels reveal that the type and intensity of external stressors are not uniform across the landscape and that male and female grizzly bears may be exposed to, or perceive, potential stressors differently. We suggest observed spatial patterns of long-term stress may be the result of the availability and distribution of foods related to disturbance features, potential sexual segregation in available habitat selection, and may not be influenced by sources of mortality which represent acute traumas. In this wildlife system and others

  1. Spatial analysis of factors influencing long-term stress in the grizzly bear (Ursus arctos) population of Alberta, Canada.

    PubMed

    Bourbonnais, Mathieu L; Nelson, Trisalyn A; Cattet, Marc R L; Darimont, Chris T; Stenhouse, Gordon B

    2013-01-01

    Non-invasive measures for assessing long-term stress in free ranging mammals are an increasingly important approach for understanding physiological responses to landscape conditions. Using a spatially and temporally expansive dataset of hair cortisol concentrations (HCC) generated from a threatened grizzly bear (Ursus arctos) population in Alberta, Canada, we quantified how variables representing habitat conditions and anthropogenic disturbance impact long-term stress in grizzly bears. We characterized spatial variability in male and female HCC point data using kernel density estimation and quantified variable influence on spatial patterns of male and female HCC stress surfaces using random forests. Separate models were developed for regions inside and outside of parks and protected areas to account for substantial differences in anthropogenic activity and disturbance within the study area. Variance explained in the random forest models ranged from 55.34% to 74.96% for males and 58.15% to 68.46% for females. Predicted HCC levels were higher for females compared to males. Generally, high spatially continuous female HCC levels were associated with parks and protected areas while low-to-moderate levels were associated with increased anthropogenic disturbance. In contrast, male HCC levels were low in parks and protected areas and low-to-moderate in areas with increased anthropogenic disturbance. Spatial variability in gender-specific HCC levels reveal that the type and intensity of external stressors are not uniform across the landscape and that male and female grizzly bears may be exposed to, or perceive, potential stressors differently. We suggest observed spatial patterns of long-term stress may be the result of the availability and distribution of foods related to disturbance features, potential sexual segregation in available habitat selection, and may not be influenced by sources of mortality which represent acute traumas. In this wildlife system and others

  2. Long-term variation of octocoral populations in St. John, US Virgin Islands

    NASA Astrophysics Data System (ADS)

    Lenz, Elizabeth A.; Bramanti, Lorenzo; Lasker, Howard R.; Edmunds, Peter J.

    2015-12-01

    The decline in abundance of scleractinian corals over the past three decades in the Caribbean has raised the possibility that other important benthic taxa, such as octocorals, are also changing in abundance. We used photoquadrats taken over 20 yr from reefs (7-9 m depth) at six sites on the south coast of St. John, US Virgin Islands, to test the hypothesis that octocorals have changed in abundance since 1992. Octocorals were counted in 0.25 m2 photoquadrats at 2- to 3-yr intervals and identified to genus or family. Overall, there was variation over time in population density of octocorals (pooled among taxa, and also separately for Antillogorgia spp., Gorgonia spp., and plexaurids) at each site, and densities remained unchanged or increased over 20 yr; where increases in density occurred, the effects were accentuated after 2002. The local-scale analysis was expanded to the Caribbean (including the Florida Keys) by compiling data for octocoral densities from 31 studies for reefs at ≤25 m depth between 1968 and 2013. At this scale, analyses were limited by the paucity of historical data, and despite a weak trend of higher octocoral densities in recent decades, statistically, there was no change in octocoral abundance over time. Together with data from the whole Caribbean, the present analysis suggests that octocorals have not experienced a decadal-scale decline in population density, which has occurred for many scleractinian corals.

  3. Worldwide Population Structure, Long-Term Demography, and Local Adaptation of Helicobacter pylori

    PubMed Central

    Montano, Valeria; Didelot, Xavier; Foll, Matthieu; Linz, Bodo; Reinhardt, Richard; Suerbaum, Sebastian; Moodley, Yoshan; Jensen, Jeffrey D.

    2015-01-01

    Helicobacter pylori is an important human pathogen associated with serious gastric diseases. Owing to its medical importance and close relationship with its human host, understanding genomic patterns of global and local adaptation in H. pylori may be of particular significance for both clinical and evolutionary studies. Here we present the first such whole genome analysis of 60 globally distributed strains, from which we inferred worldwide population structure and demographic history and shed light on interesting global and local events of positive selection, with particular emphasis on the evolution of San-associated lineages. Our results indicate a more ancient origin for the association of humans and H. pylori than previously thought. We identify several important perspectives for future clinical research on candidate selected regions that include both previously characterized genes (e.g., transcription elongation factor NusA and tumor necrosis factor alpha-inducing protein Tipα) and hitherto unknown functional genes. PMID:25995212

  4. Multiple Processes Regulate Long-Term Population Dynamics of Sea Urchins on Mediterranean Rocky Reefs

    PubMed Central

    Hereu, Bernat; Linares, Cristina; Sala, Enric; Garrabou, Joaquim; Garcia-Rubies, Antoni; Diaz, David; Zabala, Mikel

    2012-01-01

    We annually monitored the abundance and size structure of herbivorous sea urchin populations (Paracentrotus lividus and Arbacia lixula) inside and outside a marine reserve in the Northwestern Mediterranean on two distinct habitats (boulders and vertical walls) over a period of 20 years, with the aim of analyzing changes at different temporal scales in relation to biotic and abiotic drivers. P. lividus exhibited significant variability in density over time on boulder bottoms but not on vertical walls, and temporal trends were not significantly different between the protection levels. Differences in densities were caused primarily by variance in recruitment, which was less pronounced inside the MPA and was correlated with adult density, indicating density-dependent recruitment under high predation pressure, as well as some positive feedback mechanisms that may facilitate higher urchin abundances despite higher predator abundance. Populations within the reserve were less variable in abundance and did not exhibit the hyper-abundances observed outside the reserve, suggesting that predation effects maybe more subtle than simply lowering the numbers of urchins in reserves. A. lixula densities were an order of magnitude lower than P. lividus densities and varied within sites and over time on boulder bottoms but did not differ between protection levels. In December 2008, an exceptionally violent storm reduced sea urchin densities drastically (by 50% to 80%) on boulder substrates, resulting in the lowest values observed over the entire study period, which remained at that level for at least two years (up to the present). Our results also showed great variability in the biological and physical processes acting at different temporal scales. This study highlights the need for appropriate temporal scales for studies to fully understand ecosystem functioning, the concepts of which are fundamental to successful conservation and management. PMID:22606306

  5. Long Term Seasonal Dynamics of Synechococcus Population Structure in the Gulf of Aqaba, Northern Red Sea

    PubMed Central

    Post, Anton F.; Penno, Sigrid; Zandbank, Keren; Paytan, Adina; Huse, Susan M.; Welch, David Mark

    2011-01-01

    Spatial patterns of marine Synechococcus diversity across ocean domains have been reported on extensively. However, much less is known of seasonal and multiannual patterns of change in Synechococcus community composition. Here we report on the genotypic diversity of Synechococcus populations in the Gulf of Aqaba, Northern Red Sea, over seven annual cycles of deep mixing and stabile stratification, using ntcA as a phylogenetic marker. Synechococcus clone libraries were dominated by clade II and XII genotypes and a total of eight different clades were identified. Inclusion of ntcA sequences from the Global Ocean Sampling database in our analyses identified members of clade XII from beyond the Gulf of Aqaba, extending its known distribution. Most of the Synechococcus diversity was attributed to members of clade II during the spring bloom, while clade III contributed significantly to diversity during summer stratification. Clade XII diversity was most prevalent in fall and winter. Clade abundances were estimated from pyrosequencing of the V6 hypervariable region of 16S rRNA. Members of clade II dominated Synechococcus communities throughout the year, whereas the less frequent genotypes showed a pattern of seasonal succession. Based on the prevailing nutritional conditions we observed that clade I members thrive at higher nutrient concentrations during winter mixing. Clades V, VI and X became apparent during the transition periods between mixing and stratification. Clade III became prominent during sumeer stratification. We propose that members of clades V, VI, and X, and clade III are Synechococcus ecotypes that are adapted to intermediate and low nutrient levels respectively. This is the first time that molecular analyses have correlated population dynamics of Synechococcus genotypes with temporal fluctuations in nutrient regimes. Since these Synechococcus genotypes are routinely observed in the Gulf of Aqaba we suggest that seasonal fluctuations in nutrient levels

  6. Multiple processes regulate long-term population dynamics of sea urchins on Mediterranean rocky reefs.

    PubMed

    Hereu, Bernat; Linares, Cristina; Sala, Enric; Garrabou, Joaquim; Garcia-Rubies, Antoni; Diaz, David; Zabala, Mikel

    2012-01-01

    We annually monitored the abundance and size structure of herbivorous sea urchin populations (Paracentrotus lividus and Arbacia lixula) inside and outside a marine reserve in the Northwestern Mediterranean on two distinct habitats (boulders and vertical walls) over a period of 20 years, with the aim of analyzing changes at different temporal scales in relation to biotic and abiotic drivers. P. lividus exhibited significant variability in density over time on boulder bottoms but not on vertical walls, and temporal trends were not significantly different between the protection levels. Differences in densities were caused primarily by variance in recruitment, which was less pronounced inside the MPA and was correlated with adult density, indicating density-dependent recruitment under high predation pressure, as well as some positive feedback mechanisms that may facilitate higher urchin abundances despite higher predator abundance. Populations within the reserve were less variable in abundance and did not exhibit the hyper-abundances observed outside the reserve, suggesting that predation effects maybe more subtle than simply lowering the numbers of urchins in reserves. A. lixula densities were an order of magnitude lower than P. lividus densities and varied within sites and over time on boulder bottoms but did not differ between protection levels. In December 2008, an exceptionally violent storm reduced sea urchin densities drastically (by 50% to 80%) on boulder substrates, resulting in the lowest values observed over the entire study period, which remained at that level for at least two years (up to the present). Our results also showed great variability in the biological and physical processes acting at different temporal scales. This study highlights the need for appropriate temporal scales for studies to fully understand ecosystem functioning, the concepts of which are fundamental to successful conservation and management. PMID:22606306

  7. Immigration-extinction dynamics of stochastic populations

    NASA Astrophysics Data System (ADS)

    Meerson, Baruch; Ovaskainen, Otso

    2013-07-01

    How high should be the rate of immigration into a stochastic population in order to significantly reduce the probability of observing the population become extinct? Is there any relation between the population size distributions with and without immigration? Under what conditions can one justify the simple patch occupancy models, which ignore the population distribution and its dynamics in a patch, and treat a patch simply as either occupied or empty? We answer these questions by exactly solving a simple stochastic model obtained by adding a steady immigration to a variant of the Verhulst model: a prototypical model of an isolated stochastic population.

  8. Long-term morbidity and mortality after hospitalization with community-acquired pneumonia: a population-based cohort study.

    PubMed

    Johnstone, Jennie; Eurich, Dean T; Majumdar, Sumit R; Jin, Yan; Marrie, Thomas J

    2008-11-01

    Little is known about the long-term sequelae of community-acquired pneumonia (CAP). Therefore, we describe the long-term morbidity and mortality of patients after pneumonia requiring hospitalization. We specifically hypothesized that the Pneumonia Severity Index (PSI), designed to predict 30-day pneumonia-related mortality, would also be associated with longer-term all-cause mortality. Between 2000 and 2002, 3415 adults with CAP admitted to 6 hospitals in Edmonton, Alberta, Canada, were prospectively enrolled in a population-based cohort. At the time of hospital admission, demographic, clinical, and laboratory data were collected and the PSI was calculated for each patient. Postdischarge outcomes through to 2006 were ascertained using multiple linked administrative databases. Outcomes included all-cause mortality, hospital admissions, and re-hospitalization for pneumonia over a maximum of 5.4 years of follow-up. Follow-up data were available for 3284 (96%) patients; 66%were > or =65 years of age, 53% were male, and according to the PSI fully 63% were predicted to have greater than 18% 30-day pneumonia-related mortality (that is, PSI class IV-V). Median follow-up was 3.8 years. The 30-day, 1-year, and end of study mortality rates were 12%, 28%, and 53%, respectively. Overall, 82(19%) patients aged <45 years died compared with 1456 (67%) patients aged > or =65 years (hazard ratio [HR], 5.07; 95% confidence interval [CI], 4.06-6.34). Male patients were more likely to die than female patients during follow-up (971 [56%] vs. 767 [49%], respectively; HR, 1.20; 95% CI, 1.13-1.37). Initial PSI classification predicted not only 30-day mortality, but also long-term postdischarge mortality, with 92 (15%) of PSI class I-II patients dying compared with 616 (82%) PSI class V patients (HR, 11.80; 95% CI, 4.70-14.70). Of 2950 patients who survived the initial CAP hospitalization, 72% were hospitalized again (median, 2 admissions over follow-up) and 16% were re-hospitalized with

  9. Drastic changes in aquatic bacterial populations from the Cuatro Cienegas Basin (Mexico) in response to long-term environmental stress.

    PubMed

    Pajares, Silvia; Eguiarte, Luis E; Bonilla-Rosso, German; Souza, Valeria

    2013-12-01

    Understanding the changes of aquatic microbial community composition in response to changes in temperature and ultraviolet irradiation is relevant for predicting biogeochemical modifications in the functioning of natural microbial communities under global climate change scenarios. Herein we investigate shifts in the bacterioplankton composition in response to long-term changes in temperature and UV radiation. For this purpose, 15 mesocosms were seeded with composite aquatic microbial communities from natural pools within the Cuatro Cienegas Basin (Mexican Chihuahuan desert) and were subject to different temperatures and UV conditions. 16S rRNA gene clone libraries were obtained from water samples at the mid-point (4 months) and the end of the experiment (8 months). An increase in bacterial diversity over time was found in the treatment of constant temperature and UV protection, which suggests that stable environments promote the establishment of complex and diverse bacterial community. Drastic changes in the phylogenetic bacterioplankton composition and structure were observed in response to fluctuating temperature and increasing UV radiation and temperature. Fluctuating temperature induced the largest decrease of bacterial richness during the experiment, indicating that frequent temperature changes drive the reduction in abundance of several species, most notably autotrophs. The long-term impact of these environmental stresses reduced diversity and selected for generalist aquatic bacterial populations, such as Porphyrobacter. These changes at the community level occur at an ecological time scale, suggesting that under global warming scenarios cascade effects on the food web are possible if the microbial diversity is modified.

  10. Acute Anticholinesterase Pesticide Poisoning Caused a Long-Term Mortality Increase: A Nationwide Population-Based Cohort Study.

    PubMed

    Huang, Hung-Sheng; Hsu, Chien-Chin; Weng, Shih-Feng; Lin, Hung-Jung; Wang, Jhi-Joung; Su, Shih-Bin; Huang, Chien-Cheng; Guo, How-Ran

    2015-07-01

    Acute anticholinesterase pesticide (organophosphate and carbamate) poisoning (ACPP) often produces severe complications, and sometimes death. We investigated the long-term mortality of patients with ACPP because it is not sufficiently understood. In this retrospective nationwide population-based cohort study, 818 patients with ACPP and 16,360 healthy comparisons from 1999 to 2010 were selected from Taiwan's National Health Insurance Research Database. They were followed until 2011. Ninety-four (11.5%) ACPP patients and 793 (4.9%) comparisons died (P < 0.01) during follow-up. The incidence rate ratios (IRRs) of death were 2.5 times higher in ACPP patients than in comparisons (P < 0.01). The risk of death was particularly high in the first month after ACPP (IRR: 92.7; 95% confidence interval [CI]: 45.0-191.0) and still high for ~6 months (IRR: 3.8; 95% CI: 1.9-7.4). After adjusting for age, gender, selected comorbidities, geographic area, and monthly income, the hazard ratio of death for ACPP patients was still 2.4 times higher than for comparisons. Older age (≥35 years), male gender, diabetes mellitus, coronary artery disease, hypertension, stroke, mental disorder, and lower monthly income also predicted death. ACPP significantly increased long-term mortality. In addition to early follow-up after acute treatment, comorbidity control and socioeconomic assistance are needed for patients with ACPP.

  11. Long-term cancer risk after hysterectomy on benign indications: Population-based cohort study.

    PubMed

    Altman, Daniel; Yin, Li; Falconer, Henrik

    2016-06-01

    Hysterectomy on benign indications is associated with an increased risk for adverse health effects. However, little is known about the association between hysterectomy and subsequent cancer occurrence later in life. The purpose of this study was to assess the effect of hysterectomy on the incidence of cancer. In this population-based cohort study, we used data on 111,595 hysterectomized and 537,9843 nonhysterectomized women from nationwide Swedish Health Care registers including the Inpatient Register, the Cancer Register and the Cause of Death Register between 1973 and 2009. Hysterectomy with or without concomitant bilateral salpingo-ophorectomy (BSO) performed on benign indications was considered as exposure and incidence of primary cancers was used as outcome measure. Rare primary cancers (<100 cases for the two groups combined) were excluded from analysis. A marginal risk reduction for any cancer was observed for women with previous hysterectomy and for those with hysterectomy and concurrent BSO (HR 0.93, 95% CI 0.91-0.95 and HR 0.92, 95% CI 0.87-0.96, respectively). Compared to nonhysterectomized women, significant risks were observed for thyroid cancer (HR 1.76, 95% CI 1.45-2.14). For both hysterectomy and hysterectomy with BSO, an association with brain cancer was observed (HR 1.48, 95% CI 1.32-1.65 and HR 1.45, 95% CI 1.15-1.83, respectively). Hysterectomy, with or without BSO, was not associated with breast, lung or gastrointestinal cancer. We conclude that hysterectomy on benign indications is associated with an increased risk for thyroid and brain cancer later in life. Further research efforts are needed to identify patient groups at risk of malignancy following hysterectomy.

  12. A population genetic model to infer allotetraploid speciation and long-term evolution applied to two yarrow species.

    PubMed

    Guo, Yan-Ping; Tong, Xiao-Yuan; Wang, Lan-Wei; Vogl, Claus

    2013-07-01

    Allotetraploid speciation, that is, the generation of a hybrid tetraploid species from two diploid species, and the long-term evolution of tetraploid populations and species are important in plants. We developed a population genetic model to infer population genetic parameters of tetraploid populations from data of the progenitor and descendant species. Two yarrow species, Achillea alpina-4x and A. wilsoniana-4x, arose by allotetraploidization from the diploid progenitors, A. acuminata-2x and A. asiatica-2x. Yet, the population genetic process has not been studied in detail. We applied the model to sequences of three nuclear genes in populations of the four yarrow species and compared their pattern of variability with that in four plastid regions. The plastid data indicated that the two tetraploid species probably originated from multiple independent allopolyploidization events and have accumulated many mutations since. With the nuclear data, we found a low rate of homeologous recombination or gene conversion and a reduction in diversity relative to the level of both diploid species combined. The present analysis with a novel probabilistic model suggests a genetic bottleneck during tetraploid speciation, that the two tetraploid species have a long evolutionary history, and that they have a small amount of genetic exchange between the homeologous genomes. PMID:23574432

  13. Short-Term and Long-Term Biological Effects of Chronic Chemical Contamination on Natural Populations of a Marine Bivalve

    PubMed Central

    Graber, Marianne; Murillo, Laurence; Becquet, Vanessa; Churlaud, Carine; Fruitier-Arnaudin, Ingrid; Huet, Valérie; Lacroix, Camille; Pante, Eric; Le Floch, Stéphane; Thomas-Guyon, Hélène

    2016-01-01

    Understanding the effects of chronic chemical contamination on natural populations of marine organisms is complex due to the combined effects of different types of pollutants and environmental parameters that can modulate the physiological responses to stress. Here, we present the effects of a chronic contamination in a marine bivalve by combining multiple approaches that provide information on individual and population health. We sampled variegated scallops (Mimachlamys varia) at sites characterized by different contaminants and contamination levels to study the short and long-term (intergenerational) responses of this species to physiological stress. We used biomarkers (SOD, MDA, GST, laccase, citrate synthase and phosphatases) as indicators of oxidative stress, immune system alteration, mitochondrial respiration and general metabolism, and measured population genetic diversity at each site. In parallel, concentration of 14 trace metals and 45 organic contaminants (PAHs, PCBs, pesticides) in tissues were measured. Scallops were collected outside and during their reproductive season to investigate temporal variability in contaminant and biomarker levels. Our analyses revealed that the levels of two biomarkers (Laccase-type phenoloxidase and malondialdehyde) were significantly correlated with Cd concentration. Additionally, we observed significant seasonal differences for four of the five biomarkers, which is likely due to the scallop reproductive status at time of sampling. As a source of concern, a location that was identified as a reference site on the basis of inorganic contaminant levels presented the same level of some persistent organic pollutants (DDT and its metabolites) than more impacted sites. Finally, potential long-term effects of heavy metal contamination were observed for variegated scallops as genetic diversity was depressed in the most polluted sites. PMID:26938082

  14. Long-term occupancy trends in a data-poor dugong population in the Andaman and Nicobar archipelago.

    PubMed

    D'Souza, Elrika; Patankar, Vardhan; Arthur, Rohan; Alcoverro, Teresa; Kelkar, Nachiket

    2013-01-01

    Prioritizing efforts for conserving rare and threatened species with limited past data and lacking population estimates is predicated on robust assessments of their occupancy rates. This is particularly challenging for elusive, long-lived and wide-ranging marine mammals. In this paper we estimate trends in long-term (over 50 years) occupancy, persistence and extinction of a vulnerable and data-poor dugong (Dugong dugon) population across multiple seagrass meadows in the Andaman and Nicobar archipelago (India). For this we use hierarchical Bayesian dynamic occupancy models accounting for false negatives (detection probability<1), persistence and extinction, to two datasets: a) fragmentary long-term occurrence records from multiple sources (1959-2004, n = 40 locations), and b) systematic detection/non-detection data from current surveys (2010-2012, n = 57). Dugong occupancy across the archipelago declined by 60% (from 0.45 to 0.18) over the last 20 years and present distribution was largely restricted to sheltered bays and channels with seagrass meadows dominated by Halophila and Halodule sp. Dugongs were not found in patchy meadows with low seagrass cover. In general, seagrass habitat availability was not limiting for dugong occupancy, suggesting that anthropogenic factors such as entanglement in gillnets and direct hunting may have led to local extinction of dugongs from locations where extensive seagrass meadows still thrive. Effective management of these remnant dugong populations will require a multi-pronged approach, involving 1) protection of areas where dugongs still persist, 2) monitoring of seagrass habitats that dugongs could recolonize, 3) reducing gillnet use in areas used by dugongs, and 4) engaging with indigenous/settler communities to reduce impacts of hunting. PMID:24143180

  15. Long-Term Prediction of the Demand of Colonoscopies Generated by a Population-Based Colorectal Cancer Screening Program

    PubMed Central

    Mendivil, Joan; Andreu, Montserrat; Hernández, Cristina; Castells, Xavier

    2016-01-01

    Objective To estimate the long-term need for colonoscopies after a positive fecal immunochemical test (FIT) and post-polypectomy surveillance in the context of a population-based colorectal cancer (CRC) screening program. Methods A discrete-event simulation model was built to reproduce the process of CRC screening and post-polypectomy surveillance following European guidelines in a population of 100,000 men and women aged 50–69 years over a 20-year period. Screening consisted of biennial FIT and colonoscopy in participants with positive results. The model was mainly fed using data from the first and second rounds of a Spanish program (2010–2013). Data on post-polypectomy surveillance results were obtained from the literature. A probabilistic multivariate sensitivity analysis was performed on the effect of participation, FIT positivity, and adherence to surveillance colonoscopies. The main outcome variables were the number of colonoscopies after a positive FIT, surveillance colonoscopies, and the overall number of colonoscopies. Results An average yearly number of 1,200 colonoscopies after a positive FIT were predicted per 100,000 inhabitants with a slight increase to 1,400 at the end of the 20-year period. Surveillance colonoscopies increased to an average of 1,000 per 100,000 inhabitants in the long-term, showing certain stabilization in the last years of the 20-year simulation horizon. The results were highly sensitive to FIT positivity. Conclusions Implementing a population-based CRC screening program will increase the demand for colonoscopies, which is expected to double in 20 years, mainly due to an increase in surveillance colonoscopies. PMID:27732635

  16. Short-Term and Long-Term Biological Effects of Chronic Chemical Contamination on Natural Populations of a Marine Bivalve.

    PubMed

    Breitwieser, Marine; Viricel, Amélia; Graber, Marianne; Murillo, Laurence; Becquet, Vanessa; Churlaud, Carine; Fruitier-Arnaudin, Ingrid; Huet, Valérie; Lacroix, Camille; Pante, Eric; Le Floch, Stéphane; Thomas-Guyon, Hélène

    2016-01-01

    Understanding the effects of chronic chemical contamination on natural populations of marine organisms is complex due to the combined effects of different types of pollutants and environmental parameters that can modulate the physiological responses to stress. Here, we present the effects of a chronic contamination in a marine bivalve by combining multiple approaches that provide information on individual and population health. We sampled variegated scallops (Mimachlamys varia) at sites characterized by different contaminants and contamination levels to study the short and long-term (intergenerational) responses of this species to physiological stress. We used biomarkers (SOD, MDA, GST, laccase, citrate synthase and phosphatases) as indicators of oxidative stress, immune system alteration, mitochondrial respiration and general metabolism, and measured population genetic diversity at each site. In parallel, concentration of 14 trace metals and 45 organic contaminants (PAHs, PCBs, pesticides) in tissues were measured. Scallops were collected outside and during their reproductive season to investigate temporal variability in contaminant and biomarker levels. Our analyses revealed that the levels of two biomarkers (Laccase-type phenoloxidase and malondialdehyde) were significantly correlated with Cd concentration. Additionally, we observed significant seasonal differences for four of the five biomarkers, which is likely due to the scallop reproductive status at time of sampling. As a source of concern, a location that was identified as a reference site on the basis of inorganic contaminant levels presented the same level of some persistent organic pollutants (DDT and its metabolites) than more impacted sites. Finally, potential long-term effects of heavy metal contamination were observed for variegated scallops as genetic diversity was depressed in the most polluted sites. PMID:26938082

  17. Stochastic Population Dynamics of a Montane Ground-Dwelling Squirrel

    PubMed Central

    Hostetler, Jeffrey A.; Kneip, Eva; Van Vuren, Dirk H.; Oli, Madan K.

    2012-01-01

    Understanding the causes and consequences of population fluctuations is a central goal of ecology. We used demographic data from a long-term (1990–2008) study and matrix population models to investigate factors and processes influencing the dynamics and persistence of a golden-mantled ground squirrel (Callospermophilus lateralis) population, inhabiting a dynamic subalpine habitat in Colorado, USA. The overall deterministic population growth rate λ was 0.94±SE 0.05 but it varied widely over time, ranging from 0.45±0.09 in 2006 to 1.50±0.12 in 2003, and was below replacement (λ<1) for 9 out of 18 years. The stochastic population growth rate λs was 0.92, suggesting a declining population; however, the 95% CI on λs included 1.0 (0.52–1.60). Stochastic elasticity analysis showed that survival of adult females, followed by survival of juvenile females and litter size, were potentially the most influential vital rates; analysis of life table response experiments revealed that the same three life history variables made the largest contributions to year-to year changes in λ. Population viability analysis revealed that, when the influences of density dependence and immigration were not considered, the population had a high (close to 1.0 in 50 years) probability of extinction. However, probability of extinction declined to as low as zero when density dependence and immigration were considered. Destabilizing effects of stochastic forces were counteracted by regulating effects of density dependence and rescue effects of immigration, which allowed our study population to bounce back from low densities and prevented extinction. These results suggest that dynamics and persistence of our study population are determined synergistically by density-dependence, stochastic forces, and immigration. PMID:22479616

  18. Stochastic population dynamics of a montane ground-dwelling squirrel.

    PubMed

    Hostetler, Jeffrey A; Kneip, Eva; Van Vuren, Dirk H; Oli, Madan K

    2012-01-01

    Understanding the causes and consequences of population fluctuations is a central goal of ecology. We used demographic data from a long-term (1990-2008) study and matrix population models to investigate factors and processes influencing the dynamics and persistence of a golden-mantled ground squirrel (Callospermophilus lateralis) population, inhabiting a dynamic subalpine habitat in Colorado, USA. The overall deterministic population growth rate λ was 0.94±SE 0.05 but it varied widely over time, ranging from 0.45±0.09 in 2006 to 1.50±0.12 in 2003, and was below replacement (λ<1) for 9 out of 18 years. The stochastic population growth rate λ(s) was 0.92, suggesting a declining population; however, the 95% CI on λ(s) included 1.0 (0.52-1.60). Stochastic elasticity analysis showed that survival of adult females, followed by survival of juvenile females and litter size, were potentially the most influential vital rates; analysis of life table response experiments revealed that the same three life history variables made the largest contributions to year-to year changes in λ. Population viability analysis revealed that, when the influences of density dependence and immigration were not considered, the population had a high (close to 1.0 in 50 years) probability of extinction. However, probability of extinction declined to as low as zero when density dependence and immigration were considered. Destabilizing effects of stochastic forces were counteracted by regulating effects of density dependence and rescue effects of immigration, which allowed our study population to bounce back from low densities and prevented extinction. These results suggest that dynamics and persistence of our study population are determined synergistically by density-dependence, stochastic forces, and immigration.

  19. Effects of crop rotation and reduced nitrogen fertilisation on Apera spica-venti populations in a long-term experiment.

    PubMed

    Schulz, A; Pallurt, B; Gerowitt, B

    2011-01-01

    Apera spica-venti is one of the most serious annual grass weeds in Germany and may cause considerably yield losses in untreated fields. A long-term field experiment was conducted investigating the effects of crop rotation and nitrogen fertiliser use on A. spica-venti populations. A six-field cash-crop rotation with 67% winter cereals and a six-field fodder crop rotation with 50% winter cereals were studied. The rate of tillering was in the fodder crop rotation significantly higher than in the cash crop rotation. The halving of nitrogen fertilizer dose caused a significant increase in the tillering rate. Most plants of A. spica-venti emerged in winter wheat. There was an increase of emerged A. spica-venti in winter wheat from year to year.

  20. Increased Long-Term Risk of Dementia in Patients With Carbon Monoxide Poisoning: A Population-Based Study.

    PubMed

    Wong, Chung-Shun; Lin, Ying-Chin; Hong, Li-Yee; Chen, Tzu-Ting; Ma, Hon-Ping; Hsu, Yung-Ho; Tsai, Shin-Han; Lin, Yuh-Feng; Wu, Mei-Yi

    2016-01-01

    Carbon monoxide (CO) poisoning may cause toxicity of the central nervous system and heart. However, the association between CO poisoning and long-term dementia risk remains unestablished. We investigated the incidence of dementia in patients with CO poisoning in Taiwan and evaluated whether they had a higher risk of dementia than did the general population.A nationwide population-based cohort study was conducted among patients with CO poisoning identified using Taiwan's National Health Insurance Research Database (NHIRD) during 2004 to 2013. CO poisoning was defined according to the International Classification of Diseases, Ninth Revision, Clinical Modification codes. The study cohort comprised patients with CO poisoning between 2005 and 2010 (N = 14,590). Each patient was age-, sex-, and index date-matched with 4 randomly selected controls from the comparison cohort (N = 58,360). All patients were followed from the study date until dementia development, death, or the end of 2013. Cox proportional hazards regressions were performed for comparing the hazard ratios for dementia between the 2 cohorts.Incident cases of dementia were identified from the NHIRD.After adjustment for potential confounders, the study cohort was independently associated with a higher dementia risk (adjusted hazard ratio, 2.75; 95% confidence interval, 2.26-3.35).This population-based cohort study indicated that patients with CO poisoning have a higher risk of dementia than do people without CO poisoning.

  1. Long-term Prairie Falcon population changes in relation to prey abundance, weather, land uses, and habitat conditions

    USGS Publications Warehouse

    Steenhof, K.; Kochert, M.N.; Carpenter, L.B.; Lehman, R.N.

    1999-01-01

    We studied a nesting population of Prairie Falcons (Falco mexicanus) in the Snake River Birds of Prey National Conservation Area (NCA) from 1974-1997 to identify factors that influence abundance and reproduction. Our sampling period included two major droughts and associated crashes in Townsend's ground squirrel (Spermophilus townsendii) populations. The number of Prairie Falcon pairs found on long-term survey segments declined significantly from 1976-1997. Early declines were most severe at the eastern end of the NCA, where fires and agriculture have changed native shrubsteppe habitat. More recent declines occurred in the portion of canyon near the Orchard Training Area (OTA), where the Idaho Army National Guard conducts artillery firing and tank maneuvers. Overall Prairie Falcon reproductive rates were tied closely to annual indexes of ground squirrel abundance, but precipitation before and during the breeding season was related inversely to some measures of reproduction. Most reproductive parameters showed no significant trends over time, but during the 1990s, nesting success and productivity were lower in the stretch of canyon near the OTA than in adjacent areas. Extensive shrub loss, by itself, did not explain the pattern of declines in abundance and reproduction that we observed. Recent military training activities likely have interacted with fire and livestock grazing to create less than favorable foraging opportunities for Prairie Falcons in a large part of the NCA. To maintain Prairie Falcon populations in the NCA, managers should suppress wildfires, restore native plant communities, and regulate potentially incompatible land uses.

  2. Long-term prairie falcon population changes in relation to prey abundance, weather, land uses, and habitat conditions

    USGS Publications Warehouse

    Steenhof, Karen; Kochert, Michael N.; Carpenter, L.B.; Lehman, Robert N.

    1999-01-01

    We studied a nesting population of Prairie Falcons( Falco mexicanus) in the Snake River Birds of Prey National Conservation Area (NCA) from 1974-1997 to identify factors that influence abundance and reproduction. Our sampling period included two major droughts and associated crashes in Townsenda??s ground squirrel (Spermophilus townsendii) populations. The number of Prairie Falcon pairs found on long-term survey segments declined significantly from 1976-1997. Early declines were most severe at the eastern end of the NCA, where fires and agriculture have changed native shrubsteppe habitat. More recent declines occurred in the portion of canyon near the Orchard Training Area (OTA), where the Idaho Army National Guard conducts artillery firing and tank maneuvers. Overall Prairie Falcon reproductive rates were tied closely to annual indexes of ground squirrel abundance, but precipitation before and during the breeding season was related inversely to some measures of reproduction. Most reproductive parameters showed no significant trends over time, but during the 199Os, nesting success and productivity were lower in the stretch of canyon near the OTA than in adjacent areas. Extensive shrub loss, by itself, did not explain the pattern of declines in abundance and reproduction that we observed. Recent military training activities likely have interacted with fire and livestock grazing to create less than favorable foraging opportunities for Prairie Falcons in a large part of the NCA. To maintain Prairie Falcon populations in the NCA, managers should suppress wildfires, restore native plant communities, and regulate potentially incompatible land uses.

  3. Population pharmacokinetic model of THC integrates oral, intravenous, and pulmonary dosing and characterizes short- and long-term pharmacokinetics.

    PubMed

    Heuberger, Jules A A C; Guan, Zheng; Oyetayo, Olubukayo-Opeyemi; Klumpers, Linda; Morrison, Paul D; Beumer, Tim L; van Gerven, Joop M A; Cohen, Adam F; Freijer, Jan

    2015-02-01

    Δ(9)-Tetrahydrocannobinol (THC), the main psychoactive compound of Cannabis, is known to have a long terminal half-life. However, this characteristic is often ignored in pharmacokinetic (PK) studies of THC, which may affect the accuracy of predictions in different pharmacologic areas. For therapeutic use for example, it is important to accurately describe the terminal phase of THC to describe accumulation of the drug. In early clinical research, the THC challenge test can be optimized through more accurate predictions of the dosing sequence and the wash-out between occasions in a crossover setting, which is mainly determined by the terminal half-life of the compound. The purpose of this study is to better quantify the long-term pharmacokinetics of THC. A population-based PK model for THC was developed describing the profile up to 48 h after an oral, intravenous, and pulmonary dose of THC in humans. In contrast to earlier models, the current model integrates all three major administration routes and covers the long terminal phase of THC. Results show that THC has a fast initial and intermediate half-life, while the apparent terminal half-life is long (21.5 h), with a clearance of 38.8 L/h. Because the current model characterizes the long-term pharmacokinetics, it can be used to assess the accumulation of THC in a multiple-dose setting and to forecast concentration profiles of the drug under many different dosing regimens or administration routes. Additionally, this model could provide helpful insights into the THC challenge test used for the development of (novel) compounds targeting the cannabinoid system for different therapeutic applications and could improve decision making in future clinical trials.

  4. Prevalence of unknown and untreated arrhythmias in an older outpatient population screened by wireless long-term recording ECG

    PubMed Central

    Lindberg, Terese; Bohman, Doris M; Elmståhl, Sölve; Jogréus, Claes; Sanmartin Berglund, Johan

    2016-01-01

    Purpose With longer life expectancies, the prevalence of arrhythmias is increasing; thus, there is a need for new methods to screen the older outpatient population. This population-based study describes the prevalence of arrhythmias in 200 outpatients aged ≥66 years. We also investigated the feasibility of wireless long-term recording (LTR) using the ECG-BodyKom®. Methods Two hundred elderly persons aged 66–93 years were recruited from the Swedish National Study on Aging and Care in 2010–2013, and data were collected via wireless LTR ECG-BodyKom. Results Screening with the LTR ECG revealed that persistent atrial fibrillation (AF) occurred in 10% of the outpatient population aged ≥66 years. Paroxysmal AF occurred in 5.5% of the population, with no difference between younger (60–80 years) and older (>80 years) elderly participants. Furthermore, all patients with paroxysmal AF had a CHA2DS2VASc score of ≥2 and were therefore potential candidates for follow-up and medical examination. LTR ECG-BodyKom can be considered a feasible method to screen for arrhythmias in older outpatient populations. This simple method requires little of the user, and there was high satisfaction with the equipment and a good overall experience wearing it. Conclusion The increasing occurrence of arrhythmias in the older population, as well as the high number of untreated cases of arrhythmias such as persistent AF and paroxysmal AF, poses a challenge for health care. Therefore, it is essential to develop effective strategies for their prevention and treatment. PMID:27570450

  5. Long-term effects of single and combined introductions of antibiotics and bacteriophages on populations of Pseudomonas aeruginosa.

    PubMed

    Torres-Barceló, Clara; Franzon, Blaise; Vasse, Marie; Hochberg, Michael E

    2016-04-01

    With escalating resistance to antibiotics, there is an urgent need to develop alternative therapies against bacterial pathogens and pests. One of the most promising is the employment of bacteriophages (phages), which may be highly specific and evolve to counter antiphage resistance. Despite an increased understanding of how phages interact with bacteria, we know very little about how their interactions may be modified in antibiotic environments and, reciprocally, how phage may affect the evolution of antibiotic resistance. We experimentally evaluated the impacts of single and combined applications of antibiotics (different doses and different types) and phages on in vitro evolving populations of the opportunistic pathogen Pseudomonas aeruginosa PAO1. We also assessed the effects of past treatments on bacterial virulence in vivo, employing larvae of Galleria mellonella to survey the treatment consequences for the pathogen. We find a strong synergistic effect of combining antibiotics and phages on bacterial population density and in limiting their recovery rate. Our long-term study establishes that antibiotic dose is important, but that effects are relatively insensitive to antibiotic type. From an applied perspective, our results indicate that phages can contribute to managing antibiotic resistance levels, with limited consequences for the evolution of bacterial virulence.

  6. Untangling individual variation in natural populations: ecological, genetic and epigenetic correlates of long-term inequality in herbivory.

    PubMed

    Herrera, C M; Bazaga, P

    2011-04-01

    Individual variation in ecologically important features of organisms is a crucial element in ecology and evolution, yet disentangling its underlying causes is difficult in natural populations. We applied a genomic scan approach using amplified fragment length polymorphism (AFLP) markers to quantify the genetic basis of long-term individual differences in herbivory by mammals at a wild population of the violet Viola cazorlensis monitored for two decades. In addition, methylation-sensitive amplified polymorphism (MSAP) analyses were used to investigate the association between browsing damage and epigenetic characteristics of individuals, an aspect that has been not previously explored for any wild plant. Structural equation modelling was used to identify likely causal structures linking genotypes, epigenotypes and herbivory. Individuals of V. cazorlensis differed widely in the incidence of browsing mammals over the 20-year study period. Six AFLP markers (1.6% of total) were significantly related to herbivory, accounting altogether for 44% of population-wide variance in herbivory levels. MSAP analyses revealed considerable epigenetic variation among individuals, and differential browsing damage was significantly related to variation in multilocus epigenotypes. In addition, variation across plants in epigenetic characteristics was related to variation in several herbivory-related AFLP markers. Statistical comparison of alternative causal models suggested that individual differences in herbivory are the outcome of a complex causal structure where genotypes and epigenotypes are interconnected and have direct and indirect effects on herbivory. Insofar as methylation states of MSAP markers influential on herbivory are transgenerationally heritable, herbivore-driven evolutionary changes at the study population will involve correlated changes in genotypic and epigenotypic distributions.

  7. Primary prevention with lipid lowering drugs and long term risk of vascular events in older people: population based cohort study

    PubMed Central

    Alpérovitch, Annick; Kurth, Tobias; Bertrand, Marion; Ancelin, Marie-Laure; Helmer, Catherine; Debette, Stéphanie

    2015-01-01

    Objective To determine the association between use of lipid lowering drugs (statin or fibrate) in older people with no known history of vascular events and long term risk of coronary heart disease and stroke Design Ongoing prospective population based cohort study recruited in 1999-2000, with five face-to-face examinations. Setting Random sample of community dwelling population aged 65 years and over, living in three French cities (Bordeaux, Dijon, Montpellier). Participants 7484 men and women (63%) with mean age 73.9 years and no known history of vascular events at entry. Mean follow-up was 9.1 years. Main outcome measures Adjusted hazard ratios of coronary heart disease and stroke in baseline lipid lowering drug users compared with non-users, calculated using multivariable Cox proportional hazard models adjusted for numerous potential confounding factors. Hazard ratios were estimated for use of any lipid lowering drug and for statin and fibrate separately. Results Lipid lowering drug users were at decreased risk of stroke compared with non-users (hazard ratio 0.66, 95% confidence interval 0.49 to 0.90); hazard ratios for stroke were similar for statin (0.68, 0.45 to1.01) and fibrate (0.66, 0.44 to 0.98). No association was found between lipid lowering drug use and coronary heart disease (hazard ratio 1.12, 0.90 to 1.40). Analyses stratified by age, sex, body mass index, hypertension, systolic blood pressure, triglyceride concentrations, and propensity score did not show any effect modification by these variables, either for stroke or for coronary heart disease. Conclusion In a population based cohort of older people with no history of vascular events, use of statins or fibrates was associated with a 30% decrease in the incidence of stroke. PMID:25989805

  8. Long-term data reveal a population decline of the tropical lizard Anolis apletophallus, and a negative affect of el nino years on population growth rate.

    PubMed

    Stapley, Jessica; Garcia, Milton; Andrews, Robin M

    2015-01-01

    Climate change threatens biodiversity worldwide, however predicting how particular species will respond is difficult because climate varies spatially, complex factors regulate population abundance, and species vary in their susceptibility to climate change. Studies need to incorporate these factors with long-term data in order to link climate change to population abundance. We used 40 years of lizard abundance data and local climate data from Barro Colorado Island to ask how climate, total lizard abundance and cohort-specific abundance have changed over time, and how total and cohort-specific abundance relate to climate variables including those predicted to make the species vulnerable to climate change (i.e. temperatures exceeding preferred body temperature). We documented a decrease in lizard abundance over the last 40 years, and changes in the local climate. Population growth rate was related to the previous years' southern oscillation index; increasing following cooler-wetter, la niña years, decreasing following warmer-drier, el nino years. Within-year recruitment was negatively related to rainfall and minimum temperature. This study simultaneously identified climatic factors driving long-term population fluctuations and climate variables influencing short-term annual recruitment, both of which may be contributing to the population decline and influence the population's future persistence.

  9. Bogalusa Heart Study: a long-term community study of a rural biracial (Black/White) population.

    PubMed

    Berenson, G S

    2001-11-01

    The Bogalusa Heart Study, a long-term population study with a continued relationship with a community, addresses the problem of capacity building in minority health research. The study was originally funded as a Specialized Center of Research-Arteriosclerosis (SCOR-A) by the National Heart Lung and Blood Institute (NHLBI). These centers were to conduct research on atherosclerosis, coronary artery disease (CAD), hypertension, diabetes mellitus, and complications of cardiovascular-renal disease as the major causes of deaths in the United States. From earlier research on atherosclerosis, we became interested in the underlying characteristics in early life that would eventually lead to clinical morbidity and mortality from heart disease. An observation at autopsy showed the degree of atherosclerotic involvement in human aortas, from young to older individuals (Figure 1). For example, at age 40 years, marked individual variability occurred in the severity and involvement with atherosclerotic disease. Some individuals showed very little disease, while almost 70% of the surface was diseased in others. Further studies on arterial wall matrix showed aortas from young individuals varied with the extent of disease and its chemical composition. This background stimulated an interest in studying children for early clinical evidence of major adult heart diseases. The Bogalusa Heart Study was begun in 1972 as an epidemiology study of cardiovascular risk factors in children and adolescents; it eventually evolved into observations of young adults. Bogalusa, LA, is a biracial (black/white) rural community 70 miles north of New Orleans, comparable to many other communities in southeastern United States.

  10. Bogalusa Heart Study: a long-term community study of a rural biracial (black/white) population.

    PubMed

    Berenson, G S

    2001-11-01

    The Bogalusa Heart Study, a long-term population study with a continued relationship with a community, addresses the problem of capacity building in minority health research. The study was originally funded as a Specialized Center of Research-Arteriosclerosis (SCOR-A) by the National Heart Lung and Blood Institute (NHLBI). These centers were to conduct research on atherosclerosis, coronary artery disease (CAD), hypertension, diabetes mellitus, and complications of cardiovascular-renal disease as the major causes of deaths in the United States. From earlier research on atherosclerosis, we became interested in the underlying characteristics in early life that would eventually lead to clinical morbidity and mortality from heart disease. An observation at autopsy showed the degree of atherosclerotic involvement in human aortas, from young to older individuals (Figure 1). For example, at age 40 years, marked individual variability occurred in the severity and involvement with atherosclerotic disease. Some individuals showed very little disease, while almost 70% of the surface was diseased in others. Further studies on arterial wall matrix showed aortas from young individuals varied with the extent of disease and its chemical composition. This background stimulated an interest in studying children for early clinical evidence of major adult heart diseases. The Bogalusa Heart Study was begun in 1972 as an epidemiology study of cardiovascular risk factors in children and adolescents; it eventually evolved into observations of young adults. Bogalusa, LA, is a biracial (black/white) rural community 70 miles north of New Orleans, comparable to many other communities in southeastern United States.

  11. Gaps in understanding health and engagement with healthcare providers across common long-term conditions: a population survey of health literacy in 29 473 Danish citizens

    PubMed Central

    Friis, Karina; Lasgaard, Mathias; Osborne, Richard H; Maindal, Helle T

    2016-01-01

    Objectives To (1) quantify levels of subjective health literacy in people with long-term health conditions (diabetes, cardiovascular disease, chronic obstructive pulmonary disease, musculoskeletal disorders, cancer and mental disorders) and compare these to levels in the general population and (2) examine the association between health literacy, socioeconomic characteristics and comorbidity in each long-term condition group. Design Population-based survey in the Central Denmark Region (n=29 473). Main outcome measures Health literacy was measured using two scales from the Health Literacy Questionnaire (HLQ): (1) Ability to understand health information and (2) Ability to actively engage with healthcare providers. Results People with long-term conditions reported more difficulties than the general population in understanding health information and actively engaging with healthcare providers. Wide variation was found between disease groups, with people with cancer having fewer difficulties and people with mental health disorders having more difficulties in actively engaging with healthcare providers than other long-term condition groups. Having more than one long-term condition was associated with more difficulty in engaging with healthcare providers and understanding health information. People with low levels of education had lower health literacy than people with high levels of education. Conclusions Compared with the general population, people with long-term conditions report more difficulties in understanding health information and engaging with healthcare providers. These two dimensions are critical to the provision of patient-centred healthcare and for optimising health outcomes. More effort should be made to respond to the health literacy needs among individuals with long-term conditions, multiple comorbidities and low education levels, to improve health outcomes and to reduce social inequality in health. PMID:26769783

  12. Short and long-term effects of hydraulic dredging on benthic communities and ocean quahog (Arctica islandica) populations.

    PubMed

    Ragnarsson, Stefán Áki; Thorarinsdóttir, Gudrún G; Gunnarsson, Karl

    2015-08-01

    The short and long-term effects of hydraulic dredging on ocean quahog (Arctica islandica) populations and on non-target organisms were examined in Þistilfjörður Bay, NE Iceland over a five-year period. The overall species richness was low and the fauna was composed of species typical of sandy seabeds characterised by frequent wave-induced disturbances. The initial effects of dredging on the overall benthic community were large. Most taxa were significantly affected by dredging, with abundances sometimes decreasing or increasing by more than 50% immediately after dredging. However, with the exception of the ocean quahog, their recovery was rapid, and most taxa attained similar abundances as in the undisturbed control sediments after three months, and all did so after about a year. The effects of dredging on ocean quahogs were drastic and long-lasting. Of the original ocean quahog biomass before fishing took place, the dredge captured 82%, while a further 11% was lost as a result of mortality due to shell damage and predation. The total direct and indirect loss of ocean quahog biomass within dredged tracks due to fishing was thus 93%. The recovery of ocean quahogs in fished areas was extremely slow. Five years after dredging, the total ocean quahog biomass in tracks had increased from 7% to 26% relative to that in the controls. The proportional increase among ocean quahogs of targeted sizes (>70 mm) was from 2% to 14% over the same period. This study shows that while the longer-term effects of hydraulic dredging on non-target benthic organisms were small, the effects of dredging on ocean quahog densities were drastic, with full recovery expected to take place on decadal time-scales. The impacts of dredging on ocean quahog populations at the scale of the fishery are discussed. PMID:26149090

  13. Short and long-term effects of hydraulic dredging on benthic communities and ocean quahog (Arctica islandica) populations.

    PubMed

    Ragnarsson, Stefán Áki; Thorarinsdóttir, Gudrún G; Gunnarsson, Karl

    2015-08-01

    The short and long-term effects of hydraulic dredging on ocean quahog (Arctica islandica) populations and on non-target organisms were examined in Þistilfjörður Bay, NE Iceland over a five-year period. The overall species richness was low and the fauna was composed of species typical of sandy seabeds characterised by frequent wave-induced disturbances. The initial effects of dredging on the overall benthic community were large. Most taxa were significantly affected by dredging, with abundances sometimes decreasing or increasing by more than 50% immediately after dredging. However, with the exception of the ocean quahog, their recovery was rapid, and most taxa attained similar abundances as in the undisturbed control sediments after three months, and all did so after about a year. The effects of dredging on ocean quahogs were drastic and long-lasting. Of the original ocean quahog biomass before fishing took place, the dredge captured 82%, while a further 11% was lost as a result of mortality due to shell damage and predation. The total direct and indirect loss of ocean quahog biomass within dredged tracks due to fishing was thus 93%. The recovery of ocean quahogs in fished areas was extremely slow. Five years after dredging, the total ocean quahog biomass in tracks had increased from 7% to 26% relative to that in the controls. The proportional increase among ocean quahogs of targeted sizes (>70 mm) was from 2% to 14% over the same period. This study shows that while the longer-term effects of hydraulic dredging on non-target benthic organisms were small, the effects of dredging on ocean quahog densities were drastic, with full recovery expected to take place on decadal time-scales. The impacts of dredging on ocean quahog populations at the scale of the fishery are discussed.

  14. Association of folate deficiency and selected tumor marker concentrations in long-term hexavalent chromium exposed population.

    PubMed

    Wang, Tian-Cheng; Song, Yan-Shuang; Yu, Shan-Fa; Zhang, Ji; Wang, Hui; Gu, Yong-En; Chen, Tian; Jia, Guang

    2014-01-01

    Both hexavalent chromium [Cr (VI)] exposure and folate deficiency have been associated with increased cancer risks. Our previous studies have found folate deficiency in Cr (VI) exposed population. Here the relationship between some tumor markers and folate status in long-term Cr (VI) exposure was investigated carefully to show the multiple aspects of Cr (VI) carcinogenesis. A group of 115 workers occupationally exposed to chromate and 60 matched, unexposed controls in Shandong province of China were recruited. Environmental and biological exposure assessments including personal exposure to airborne Cr and Cr contents in erythrocytes were performed. Serum folate, plasma total homocysteine (tHcy) and plasma carcinoembryonic antigen (CEA), neuron specific enolase (NSE), squamous cell carcinoma antigen (SCC), cytokeratin fragment antigen 21-1 (CYFRA 21-1), cancer antigen 72-4 (CA72-4), as well as α-fetoprotein (AFP) were measured. Smoking index (SI) was also calculated to discriminate possible confounding effects of smoking status. Serum folate level decreased significantly, while plasma tHcy, CEA, NSE, SCC, CYFRA21-1, CA72-4 and AFP concentrations increased significantly after Cr (VI) exposure. Meanwhile, plasma CEA, NSE and SCC were negatively correlated with serum folate. SI was negatively correlated with serum folate but positively correlated with plasma tHcy, CEA and NSE levels. Present study suggests that folate deficiency was associated with increased cancer risks and might be affected by smoking in Cr (VI) exposed population. Folate might play a key role in Cr (VI) carcinogenesis although further detailed investigations are needed to clarify the mechanism of this process. PMID:23623598

  15. Bayesian age-period-cohort models with versatile interactions and long-term predictions: mortality and population in Finland 1878-2050.

    PubMed

    Havulinna, Aki S

    2014-02-28

    Age-period-cohort (APC) models are widely used for studying time trends of disease incidence or mortality. Model identifiability has become less of a problem with Bayesian APC models. These models are usually based on random walk (RW1, RW2) smoothing priors. For long and complex time series and for long predicted periods, these models as such may not be adequate. We present two extensions for the APC models. First, we introduce flexible interactions between the age, period and cohort effects based on a two-dimensional conditional autoregressive smoothing prior on the age/period plane. Our second extension uses autoregressive integrated (ARI) models to provide reasonable long-term predictions. To illustrate the utility of our model framework, we provide stochastic predictions for the Finnish male and female population, in 2010-2050. For that, we first study and forecast all-cause male and female mortality in Finland, 1878-2050, showing that using an interaction term is needed for fitting and interpreting the observed data. We then provide population predictions using a cohort component model, which also requires predictions for fertility and migration. As our main conclusion, ARI models have better properties for predictions than the simple RW models do, but mixing these prediction models with RW1 or RW2 smoothing priors for observed periods leads to a model that is not fully consistent. Further research with our model framework will concentrate on using a more consistent model for smoothing and prediction, such as autoregressive integrated moving average models with state-space methods or Gaussian process priors. PMID:24105769

  16. Long-Term Care

    MedlinePlus

    ... this page please turn Javascript on. Long-Term Care What Is Long-Term Care? Long-term care involves a variety of services ... the Escape (Esc) button on your keyboard.) Most Care Provided at Home Long-term care is provided ...

  17. Randomised controlled trial of the effect of long-term selenium supplementation on plasma cholesterol in an elderly Danish population.

    PubMed

    Cold, Frederik; Winther, Kristian H; Pastor-Barriuso, Roberto; Rayman, Margaret P; Guallar, Eliseo; Nybo, Mads; Griffin, Bruce A; Stranges, Saverio; Cold, Søren

    2015-12-14

    Although cross-sectional studies have shown a positive association between Se and cholesterol concentrations, a recent randomised controlled trial in 501 elderly UK individuals of relatively low-Se status found that Se supplementation for 6 months lowered total plasma cholesterol. The Danish PRECISE (PREvention of Cancer by Intervention with Selenium) pilot study (ClinicalTrials.gov ID: NCT01819649) was a 5-year randomised, double-blinded, placebo-controlled trial with four groups (allocation ratio 1:1:1:1). Men and women aged 60-74 years (n 491) were randomised to 100 (n 124), 200 (n 122) or 300 (n 119) μg Se-enriched yeast or matching placebo-yeast tablets (n 126) daily for 5 years. A total of 468 participants continued the study for 6 months and 361 participants, equally distributed across treatment groups, continued for 5 years. Plasma samples were analysed for total and HDL-cholesterol and for total Se concentrations at baseline, 6 months and 5 years. The effect of different doses of Se supplementation on plasma lipid and Se concentrations was estimated by using linear mixed models. Plasma Se concentration increased significantly and dose-dependently in the intervention groups after 6 months and 5 years. Total cholesterol decreased significantly both in the intervention groups and in the placebo group after 6 months and 5 years, with small and nonsignificant differences in changes in plasma concentration of total cholesterol, HDL-cholesterol, non-HDL-cholesterol and total:HDL-cholesterol ratio between intervention and placebo groups. The effect of long-term supplementation with Se on plasma cholesterol concentrations or its sub-fractions did not differ significantly from placebo in this elderly population. PMID:26420334

  18. Randomised controlled trial of the effect of long-term selenium supplementation on plasma cholesterol in an elderly Danish population.

    PubMed

    Cold, Frederik; Winther, Kristian H; Pastor-Barriuso, Roberto; Rayman, Margaret P; Guallar, Eliseo; Nybo, Mads; Griffin, Bruce A; Stranges, Saverio; Cold, Søren

    2015-12-14

    Although cross-sectional studies have shown a positive association between Se and cholesterol concentrations, a recent randomised controlled trial in 501 elderly UK individuals of relatively low-Se status found that Se supplementation for 6 months lowered total plasma cholesterol. The Danish PRECISE (PREvention of Cancer by Intervention with Selenium) pilot study (ClinicalTrials.gov ID: NCT01819649) was a 5-year randomised, double-blinded, placebo-controlled trial with four groups (allocation ratio 1:1:1:1). Men and women aged 60-74 years (n 491) were randomised to 100 (n 124), 200 (n 122) or 300 (n 119) μg Se-enriched yeast or matching placebo-yeast tablets (n 126) daily for 5 years. A total of 468 participants continued the study for 6 months and 361 participants, equally distributed across treatment groups, continued for 5 years. Plasma samples were analysed for total and HDL-cholesterol and for total Se concentrations at baseline, 6 months and 5 years. The effect of different doses of Se supplementation on plasma lipid and Se concentrations was estimated by using linear mixed models. Plasma Se concentration increased significantly and dose-dependently in the intervention groups after 6 months and 5 years. Total cholesterol decreased significantly both in the intervention groups and in the placebo group after 6 months and 5 years, with small and nonsignificant differences in changes in plasma concentration of total cholesterol, HDL-cholesterol, non-HDL-cholesterol and total:HDL-cholesterol ratio between intervention and placebo groups. The effect of long-term supplementation with Se on plasma cholesterol concentrations or its sub-fractions did not differ significantly from placebo in this elderly population.

  19. Sources of variability in spotted owl population growth rate: testing predictions using long-term mark-recapture data.

    PubMed

    Seamans, Mark E; Gutiérrez, R J

    2007-05-01

    For long-lived iteroparous vertebrates that annually produce few young, life history theory predicts that reproductive output (R) and juvenile survival should influence temporal variation in population growth rate (lambda) more than adult survival does. We examined this general prediction using 15 years of mark-recapture data from a population of California spotted owls (Strix occidentalis occidentalis). We found that survival of individuals > or =1 year old (phi) exhibited much less temporal variability (CV = 0.04), where CV is coefficient of variation, than R (CV = 0.83) and that R was strongly influenced by environmental stochasticity. Although lambda was most sensitive (ê; log-transformed sensitivity) to phi (ê = 0.77), and much less sensitive to either R (ê = 0.12) or juvenile survival (survival rate of owls from fledging to 1 year old; ê = 0.12), we estimated that R contributed as much as phi to the observed annual variability in lambda. The contribution of juvenile survival to variability in lambda was proportional to its ê. These results are consistent with the hypothesis that natural selection may have favored the evolution of longevity in spotted owls as a strategy to increase the probability of experiencing favorable years for reproduction. Our finding that annual weather patterns that most affected R (temperature and precipitation during incubation) and phi (conditions during winter related to the Southern Oscillation Index) were equally good at explaining temporal variability in lambda supports the conclusion that R and phi were equally responsible for variability in lambda. Although currently accepted conservation measures for spotted owl populations attempt to enhance survival, our results indicated that conservation measures that target R may be as successful, as long as actions do not reduce phi. PMID:17160689

  20. The Chronicity of Self-Injurious Behaviour: A Long-Term Follow-Up of a Total Population Study

    ERIC Educational Resources Information Center

    Taylor, Lorne; Oliver, Chris; Murphy, Glynis

    2011-01-01

    Background: Self-injurious behaviour (SIB) is a relatively common problem for people with intellectual disabilities and it is known to be associated with various risk markers, such as degree of disability, sensory impairments, and autism (McClintock "et al." 2003). Less is known about its long-term course however. Method: The present study was…

  1. Spotlight on "Long-Term English Language Learners": Characteristics and Prior Schooling Experiences of an Invisible Population

    ERIC Educational Resources Information Center

    Menken, Kate; Kleyn, Tatyana; Chae, Nabin

    2012-01-01

    This article presents qualitative research findings about the characteristics and prior schooling experiences of "long-term English language learners" (LTELLs), who have attended U.S. schools for 7 years or more, and about whom there is little empirical research, despite their significant numbers. Findings indicate that these students are orally…

  2. Stochastic population dynamics in populations of western terrestrial garter snakes with divergent life histories

    USGS Publications Warehouse

    Miller, David A.; Clark, W.R.; Arnold, S.J.; Bronikowski, A.M.

    2011-01-01

    Comparative evaluations of population dynamics in species with temporal and spatial variation in life-history traits are rare because they require long-term demographic time series from multiple populations. We present such an analysis using demographic data collected during the interval 1978-1996 for six populations of western terrestrial garter snakes (Thamnophis elegans) from two evolutionarily divergent ecotypes. Three replicate populations from a slow-living ecotype, found in mountain meadows of northeastern California, were characterized by individuals that develop slowly, mature late, reproduce infrequently with small reproductive effort, and live longer than individuals of three populations of a fast-living ecotype found at lakeshore locales. We constructed matrix population models for each of the populations based on 8-13 years of data per population and analyzed both deterministic dynamics based on mean annual vital rates and stochastic dynamics incorporating annual variation in vital rates. (1) Contributions of highly variable vital rates to fitness (??s) were buffered against the negative effects of stochastic variation, and this relationship was consistent with differences between the meadow (M-slow) and lakeshore (L-fast) ecotypes. (2) Annual variation in the proportion of gravid females had the greatest negative effect among all vital rates on ?? s. The magnitude of variation in the proportion of gravid females and its effect on ??s was greater in M-slow than L-fast populations. (3) Variation in the proportion of gravid females, in turn, depended on annual variation in prey availability, and its effect on ??s was 4- 23 times greater in M-slow than L-fast populations. In addition to differences in stochastic dynamics between ecotypes, we also found higher mean mortality rates across all age classes in the L-fast populations. Our results suggest that both deterministic and stochastic selective forces have affected the evolution of divergent life

  3. Stochastic delocalization of finite populations

    NASA Astrophysics Data System (ADS)

    Geyrhofer, Lukas; Hallatschek, Oskar

    2013-01-01

    The localization of populations of replicating bacteria, viruses or autocatalytic chemicals arises in various contexts, such as ecology, evolution, medicine or chemistry. Several deterministic mathematical models have been used to characterize the conditions under which localized states can form, and how they break down due to convective driving forces. It has been repeatedly found that populations remain localized unless the bias exceeds a critical threshold value, and that close to the transition the population is characterized by a diverging length scale. These results, however, have been obtained upon ignoring number fluctuations (‘genetic drift’), which are inevitable given the discreteness of the replicating entities. Here, we study the localization/delocalization of a finite population in the presence of genetic drift. The population is modeled by a linear chain of subpopulations, or demes, which exchange migrants at a constant rate. Individuals in one particular deme, called ‘oasis’, receive a growth rate benefit, and the total population is regulated to have constant size N. In this ecological setting, we find that any finite population delocalizes on sufficiently long time scales. Depending on parameters, however, populations may remain localized for a very long time. The typical waiting time to delocalization increases exponentially with both population size and distance to the critical wind speed of the deterministic approximation. We augment these simulation results by a mathematical analysis that treats the reproduction and migration of individuals as branching random walks subject to global constraints. For a particular constraint, different from a fixed population size constraint, this model yields a solvable first moment equation. We find that this solvable model approximates very well the fixed population size model for large populations, but starts to deviate as population sizes are small. Nevertheless, the qualitative behavior of the

  4. Management of drug-drug interactions: considerations for special populations--focus on opioid use in the elderly and long term care.

    PubMed

    Lynch, Tom

    2011-09-01

    Elderly patients and residents in long term care facilities requiring pain medication often have multiple pharmacologic and physiologic factors that can impact the choice of analgesic. One particular problem with prescribing opioids to the elderly and long term care residents is that opioid safety and efficacy have not been well studied in these populations, and it may be difficult to predict how these patients will respond to opioid treatment. As people age, numerous physiological changes occur, which may affect opioid pharmacokinetics and the potential for drug-drug interactions (DDIs). Long term care residents include the elderly but also include many younger patients who require assistance for a variety of reasons, such as physical or mental disability. Many elderly and long term care patients have cognitive deficits that impede communication about their pain, thus making detection of opioid DDIs more difficult. Knowledge of the patient's medical history and current prescriptions can help guide the pain management team in the selection of treatment, help minimize the risk of DDIs, and provide these patients with the pain relief they require. There are several practice management recommendations for opioid therapy in the elderly and long term care residents, with the goal of optimizing analgesia while avoiding adverse events and drug interactions.

  5. Effects of capturing and collaring on polar bears: findings from long-term research on the southern Beaufort Sea population

    USGS Publications Warehouse

    Rode, Karyn D.; Pagano, Anthony M.; Bromaghin, Jeffrey F.; Atwood, Todd C.; Durner, George M.; Simac, Kristin; Amstrup, Steven C.

    2014-01-01

    Implications: This study provides empirical evidence that current capture-based research methods do not have long-term implications, and are not contributing to observed changes in body condition, reproduction or survival in the southern Beaufort Sea. Continued refinement of capture protocols, such as the use of low-impact dart rifles and reversible drug combinations, might improve polar bear response to capture and abate short-term reductions in activity and movement post-capture.

  6. Association between hyperglycaemic crisis and long-term major adverse cardiovascular events: a nationwide population-based, propensity score-matched, cohort study

    PubMed Central

    Chang, Li-Hsin; Lin, Liang-Yu; Tsai, Ming-Tsun; How, Chorng-Kuang; Chiang, Jen-Huai; Hsieh, Vivian Chia-Rong; Hu, Sung-Yuan; Hsieh, Ming-Shun

    2016-01-01

    Objective Hyperglycaemic crisis was associated with significant intrahospital morbidity and mortality. However, the association between hyperglycaemic crisis and long-term cardiovascular outcomes remained unknown. This study aimed to investigate the association between hyperglycaemic crisis and subsequent long-term major adverse cardiovascular events (MACEs). Participants and methods This population-based cohort study was conducted using data from Taiwan's National Health Insurance Research Database for the period of 1996–2012. A total of 2171 diabetic patients with hyperglycaemic crisis fit the inclusion criteria. Propensity score matching was used to match the baseline characteristics of the study cohort to construct a comparison cohort which comprised 8684 diabetic patients without hyperglycaemic crisis. The risk of long-term MACEs was compared between the two cohorts. Results Six hundred and seventy-six MACEs occurred in the study cohort and the event rate was higher than that in the comparison cohort (31.1% vs 24.1%, p<0.001). Patients with hyperglycaemic crisis were associated with a higher risk of long-term MACEs even after adjusting for all baseline characteristics and medications (adjusted HR=1.76, 95% CI 1.62 to 1.92, p<0.001). Acute myocardial infarction had the highest adjusted HR (adjusted HR=2.19, 95% CI 1.75 to 2.75, p<0.001) in the four types of MACEs, followed by congestive heart failure (adjusted HR=1.97, 95% CI 1.70 to 2.28, p<0.001). Younger patients with hyperglycaemic crisis had a higher risk of MACEs than older patients (adjusted HR=2.69 for patients aged 20–39 years vs adjusted HR=1.58 for patients aged >65 years). Conclusions Hyperglycaemic crisis was significantly associated with long-term MACEs, especially in the young population. Further prospective longitudinal study should be conducted for validation. PMID:27554106

  7. Stochastic population dynamics under resource constraints

    NASA Astrophysics Data System (ADS)

    Gavane, Ajinkya S.; Nigam, Rahul

    2016-06-01

    This paper investigates the population growth of a certain species in which every generation reproduces thrice over a period of predefined time, under certain constraints of resources needed for survival of population. We study the survival period of a species by randomizing the reproduction probabilities within a window at same predefined ages and the resources are being produced by the working force of the population at a variable rate. This randomness in the reproduction rate makes the population growth stochastic in nature and one cannot predict the exact form of evolution. Hence we study the growth by running simulations for such a population and taking an ensemble averaged over 500 to 5000 such simulations as per the need. While the population reproduces in a stochastic manner, we have implemented a constraint on the amount of resources available for the population. This is important to make the simulations more realistic. The rate of resource production then is tuned to find the rate which suits the survival of the species. We also compute the mean life time of the species corresponding to different resource production rate. Study for these outcomes in the parameter space defined by the reproduction probabilities and rate of resource production is carried out.

  8. Molecular demographic history of the annual sunflowers Helianthus annuus and H. petiolaris--large effective population sizes and rates of long-term gene flow.

    PubMed

    Strasburg, Jared L; Rieseberg, Loren H

    2008-08-01

    Hybridization between distinct species may lead to introgression of genes across species boundaries, and this pattern can potentially persist for extended periods as long as selection at some loci or genomic regions prevents thorough mixing of gene pools. However, very few reliable estimates of long-term levels of effective migration are available between hybridizing species throughout their history. Accurate estimates of divergence dates and levels of gene flow require data from multiple unlinked loci as well as an analytical framework that can distinguish between lineage sorting and gene flow and incorporate the effects of demographic changes within each species. Here we use sequence data from 18 anonymous nuclear loci in two broadly sympatric sunflower species, Helianthus annuus and H. petiolaris, analyzed within an "isolation with migration" framework to make genome-wide estimates of the ages of these two species, long-term rates of gene flow between them, and effective population sizes and historical patterns of population growth. Our results indicate that H. annuus and H. petiolaris are approximately one million years old and have exchanged genes at a surprisingly high rate (long-term N(ef)m estimates of approximately 0.5 in each direction), with somewhat higher rates of introgression from H. annuus into H. petiolaris than vice versa. In addition, each species has undergone dramatic population expansion since divergence, and both species have among the highest levels of genetic diversity reported for flowering plants. Our results provide the most comprehensive estimate to date of long-term patterns of gene flow and historical demography in a nonmodel plant system, and they indicate that species integrity can be maintained even in the face of extensive gene flow over a prolonged period.

  9. The Long-Term Relationship between Population Growth and Vegetation Cover: An Empirical Analysis Based on the Panel Data of 21 Cities in Guangdong Province, China

    PubMed Central

    Li, Chao; Kuang, Yaoqiu; Huang, Ningsheng; Zhang, Chao

    2013-01-01

    It is generally believed that there is an inverse relationship between population growth and vegetation cover. However, reports about vegetation protection and reforestation around the World have been continuously increasing in recent decades, which seems to indicate that this relationship may not be true. In this paper, we have taken 21 cities in Guangdong Province, China as the study area to test the long-term relationship between population growth and vegetation cover, using an AVHRR NDVI data set and the panel cointegrated regression method. The results show that there is a long-term inverted N-shaped curve relationship between population growth and vegetation cover in the region where there are frequent human activities and the influence of climate change on vegetation cover changes is relatively small. The two turning points of the inverted N-shaped curve for the case of Guangdong Province correspond to 2,200 persons·km−2 and 3,820 persons·km−2, and they can provide a reference range for similar regions of the World. It also states that the population urbanization may have a negative impact on the vegetation cover at the early stage, but have a positive impact at the later stage. In addition, the Panel Error Correction Model (PECM) is used to investigate the causality direction between population growth and vegetation cover. The results show that not only will the consuming destruction effect and planting construction effect induced by the population growth have a great impact on vegetation cover changes, but vegetation cover changes in turn will also affect the population growth in the long term. PMID:23435589

  10. Monitoring Tree Population Dynamics in Arid Zone Through Multiple Temporal Scales: Integration of Spatial Analysis, Change Detection and Field Long Term Monitoring

    NASA Astrophysics Data System (ADS)

    Isaacson, S.; Rachmilevitch, S.; Ephrath, J. E.; Maman, S.; Blumberg, D. G.

    2016-06-01

    High mortality rates and lack of recruitment in the acacia populations throughout the Negev Desert and the Arava rift valley of Israel have been reported in previous studies. However, it is difficult to determine whether these reports can be evidence to a significant decline trend of the trees populations. This is because of the slow dynamic processes of acaia tree populations and the lack of long term continuous monitoring data. We suggest a new data analysis technique that expands the time scope of the field long term monitoring of trees in arid environments. This will enables us to improve our understanding of the spatial and temporal changes of these populations. We implemented two different approaches in order to expand the time scope of the acacia population field survey: (1) individual based tree change detection using Corona satellite images and (2) spatial analysis of trees population, converting spatial data into temporal data. The next step was to integrate the results of the two analysis techniques (change detection and spatial analysis) with field monitoring. This technique can be implemented to other tree populations in arid environments to help assess the vegetation conditions and dynamics of those ecosystems.

  11. Too Many Is Too Bad: Long-Term Net Negative Effects of High Density Ungulate Populations on a Dominant Mediterranean Shrub

    PubMed Central

    Lecomte, Xavier; Fedriani, José M.; Caldeira, Maria C.; Clemente, Adelaide S.; Olmi, Alessandro; Bugalho, Miguel N.

    2016-01-01

    Plant–animal interactions imply costs and benefits with net balance depending on interacting species and ecological context. Ungulates, in particular, confer costs (e.g., plant leaf consumption, flower bud predation) and benefits (e.g., plant overcompensation, seed dispersal) to plants. Magnitude of costs and benefits may be altered by habitat management or ecological conditions favoring high density ungulate populations. Little is known however on whether plant costs or benefits predominate over the years, or the long-term outcomes of plant-animal interactions in habitat types sustaining high density ungulate populations. We investigated how high density ungulate populations alter plant costs and benefits by quantifying ungulate long-term effects on the shrub Cistus ladanifer (Cistaceae) individual size, seed weight and number, seed bank, and population density, through a 12-year ungulate exclusion experiment in a Mediterranean scrubland. We monitored plant size and flower buds in plants exposed or protected from ungulates and number of developed capsules and seeds consumed (potential seed dispersal) by ungulates during three reproductive seasons. We found that ungulates negatively affected shrub size and led to a dramatically decline of shrub reproductive structures and seed production, affecting the plant reproductive cycle. Number of buds was 27 times higher and number of developed seed 5 times higher in ungulate-excluded as compared to ungulate-exposed plots. After 9 years of ungulate exclusion, the C. ladanifer seed bank was 2.6 times higher in ungulate-excluded plots. The population density of C. ladanifer was 4 times higher in ungulate-excluded plots. Our long-term experiment showed that high density ungulate populations can alter plant-animal interactions by reducing plant benefits and increasing plant costs. PMID:27387134

  12. Too Many Is Too Bad: Long-Term Net Negative Effects of High Density Ungulate Populations on a Dominant Mediterranean Shrub.

    PubMed

    Lecomte, Xavier; Fedriani, José M; Caldeira, Maria C; Clemente, Adelaide S; Olmi, Alessandro; Bugalho, Miguel N

    2016-01-01

    Plant-animal interactions imply costs and benefits with net balance depending on interacting species and ecological context. Ungulates, in particular, confer costs (e.g., plant leaf consumption, flower bud predation) and benefits (e.g., plant overcompensation, seed dispersal) to plants. Magnitude of costs and benefits may be altered by habitat management or ecological conditions favoring high density ungulate populations. Little is known however on whether plant costs or benefits predominate over the years, or the long-term outcomes of plant-animal interactions in habitat types sustaining high density ungulate populations. We investigated how high density ungulate populations alter plant costs and benefits by quantifying ungulate long-term effects on the shrub Cistus ladanifer (Cistaceae) individual size, seed weight and number, seed bank, and population density, through a 12-year ungulate exclusion experiment in a Mediterranean scrubland. We monitored plant size and flower buds in plants exposed or protected from ungulates and number of developed capsules and seeds consumed (potential seed dispersal) by ungulates during three reproductive seasons. We found that ungulates negatively affected shrub size and led to a dramatically decline of shrub reproductive structures and seed production, affecting the plant reproductive cycle. Number of buds was 27 times higher and number of developed seed 5 times higher in ungulate-excluded as compared to ungulate-exposed plots. After 9 years of ungulate exclusion, the C. ladanifer seed bank was 2.6 times higher in ungulate-excluded plots. The population density of C. ladanifer was 4 times higher in ungulate-excluded plots. Our long-term experiment showed that high density ungulate populations can alter plant-animal interactions by reducing plant benefits and increasing plant costs. PMID:27387134

  13. Amerciamysis bahia Stochastic Matrix Population Model for Laboratory Populations

    EPA Science Inventory

    The population model described here is a stochastic, density-independent matrix model for integrating the effects of toxicants on survival and reproduction of the marine invertebrate, Americamysis bahia. The model was constructed using Microsoft® Excel 2003. The focus of the mode...

  14. Long-Term Changes in Cyanobacteria Populations in Lake Kinneret (Sea of Galilee), Israel: An Eco-Physiological Outlook

    PubMed Central

    Hadas, Ora; Kaplan, Aaron; Sukenik, Assaf

    2015-01-01

    The long-term record of cyanobacteria abundance in Lake Kinneret (Sea of Galilee), Israel, demonstrates changes in cyanobacteria abundance and composition in the last five decades. New invasive species of the order Nostocales (Aphanizomenon ovalisporum and Cylindrospermopsis raciborskii) became part of the annual phytoplankton assemblage during summer-autumn. Concomitantly, bloom events of Microcystis sp. (Chroococcales) during winter-spring intensified. These changes in cyanobacteria pattern may be partly attributed to the management policy in Lake Kinneret’s vicinity and watershed aimed to reduce effluent discharge to the lake and partly to climate changes in the region; i.e., increased water column temperature, less wind and reduced precipitation. The gradual decrease in the concentration of total and dissolved phosphorus and total and dissolved nitrogen and an increase in alkalinity, pH and salinity, combined with the physiological features of cyanobacteria, probably contributed to the success of cyanobacteria. The data presented here indicate that the trend of the continuous decline of nutrients may not be sufficient to reduce and to control the abundance and proliferation of toxic and non-toxic cyanobacteria. PMID:25664964

  15. Long-term changes in cyanobacteria populations in lake kinneret (sea of galilee), Israel: an eco-physiological outlook.

    PubMed

    Hadas, Ora; Kaplan, Aaron; Sukenik, Assaf

    2015-02-05

    The long-term record of cyanobacteria abundance in Lake Kinneret (Sea of Galilee), Israel, demonstrates changes in cyanobacteria abundance and composition in the last five decades. New invasive species of the order Nostocales (Aphanizomenon ovalisporum and Cylindrospermopsis raciborskii) became part of the annual phytoplankton assemblage during summer-autumn. Concomitantly, bloom events of Microcystis sp. (Chroococcales) during winter-spring intensified. These changes in cyanobacteria pattern may be partly attributed to the management policy in Lake Kinneret's vicinity and watershed aimed to reduce effluent discharge to the lake and partly to climate changes in the region; i.e., increased water column temperature, less wind and reduced precipitation. The gradual decrease in the concentration of total and dissolved phosphorus and total and dissolved nitrogen and an increase in alkalinity, pH and salinity, combined with the physiological features of cyanobacteria, probably contributed to the success of cyanobacteria. The data presented here indicate that the trend of the continuous decline of nutrients may not be sufficient to reduce and to control the abundance and proliferation of toxic and non-toxic cyanobacteria.

  16. Comparison of indigenous and exogenous microbial populations during slurry phase biodegradation of long-term hydrocarbon-contaminated soil.

    PubMed

    Aburto-Medina, Arturo; Adetutu, Eric M; Aleer, Sam; Weber, John; Patil, Sayali S; Sheppard, Petra J; Ball, Andrew S; Juhasz, Albert L

    2012-11-01

    In this study, a number of slurry-phase strategies were trialled over a 42 day period in order to determine the efficacy of bioremediation for long-term hydrocarbon-contaminated soil (145 g kg(-1) C(10)-C(40)). The addition of activated sludge and nutrients to slurries (bioaugmentation) resulted in enhanced hydrocarbon removal (51.6 ± 8.5 %) compared to treatments receiving only nutrients (enhanced natural attenuation [ENA]; 41.3 ± 6.4 %) or no amendments (natural attenuation; no significant hydrocarbon removal, P < 0.01). This data suggests that the microbial community in the activated sludge inoculum contributed to the enhanced removal of hydrocarbons in ENA slurries. Microbial diversity in slurries was monitored using DGGE with dominant bands excised and sequenced for identification. Applying the different bioremediation strategies resulted in the formation of four distinct community clusters associated with the activated sludge (inoculum), bioaugmentation strategy at day 0, bioaugmentation strategy at weeks 2-6 and slurries with autoclaved sludge and nutrient additions (bioaugmentation negative control). While hydrocarbon-degrading bacteria genera (e.g. Aquabacterium and Haliscomenobacter) were associated with the hydrocarbon-contaminated soil, bioaugmentation of soil slurries with activated sludge resulted in the introduction of bacteria associated with hydrocarbon degradation (Burkholderiales order and Klebsiella genera) which presumably contributed to the enhanced efficacy for this slurry strategy.

  17. Evaluation of long-term community recovery from Hurricane Andrew: sources of assistance received by population sub-groups.

    PubMed

    McDonnell, S; Troiano, R P; Barker, N; Noji, E; Hlady, W G; Hopkins, R

    1995-12-01

    Two three-stage cluster surveys were conducted in South Dade County, Florida, 14 months apart, to assess recovery following Hurricane Andrew. Response rates were 75 per cent and 84 per cent. Sources of assistance used in recovery from Hurricane Andrew differed according to race, per capita income, ethnicity, and education. Reports of improved living situation post-hurricane were not associated with receiving relief assistance, but reports of a worse situation were associated with loss of income, being exploited, or job loss. The number of households reporting problems with crime and community violence doubled between the two surveys. Disaster relief efforts had less impact on subjective long-term recovery than did job or income loss or housing repair difficulties. Existing sources of assistance were used more often than specific post-hurricane relief resources. The demographic make-up of a community may determine which are the most effective means to inform them after a disaster and what sources of assistance may be useful.

  18. Does long-term care use within primary health care reduce hospital use among older people in Norway? A national five-year population-based observational study

    PubMed Central

    2011-01-01

    Background Population ageing may threaten the sustainability of future health care systems. Strengthening primary health care, including long-term care, is one of several measures being taken to handle future health care needs and budgets. There is limited and inconsistent evidence on the effect of long-term care on hospital use. We explored the relationship between the total use of long-term care within public primary health care in Norway and the use of hospital beds when adjusting for various effect modifiers and confounders. Methods This national population-based observational study consists of all Norwegians (59% women) older than 66 years (N = 605676) (13.2% of total population) in 2002-2006. The unit of analysis was defined by municipality, age and sex. The association between total number of recipients of long-term care per 1000 inhabitants (LTC-rate) and hospital days per 1000 inhabitants (HD-rate) was analysed in a linear regression model. Modifying and confounding effects of socioeconomic, demographic and geographic variables were included in the final model. We defined a difference in hospitalization rates of more than 1000 days per 1000 inhabitants as clinically important. Results Thirty-one percent of women and eighteen percent of men were long-term care users. Men had higher HD-rates than women. The crude association between LTC-rate and HD-rate was weakly negative. We identified two effect modifiers (age and sex) and two strong confounders (travel time to hospital and mortality). Age and sex stratification and adjustments for confounders revealed a positive statistically significant but not clinically important relationship between LTC-rates and hospitalization for women aged 67-79 years and all men. For women 80 years and over there was a weak but negative relationship which was neither statistically significant nor clinically important. Conclusions We found a weak positive adjusted association between LTC-rates and HD-rates. Opposite to common

  19. Long-Term Effects of Metal-Rich Sewage Sludge Application on Soil Populations of Bradyrhizobium japonicum.

    PubMed

    Kinkle, B K; Angle, J S; Keyser, H H

    1987-02-01

    The application of sewage sludge to land may increase the concentration of heavy metals in soil. Of considerable concern is the effect of heavy metals on soil microorganisms, especially those involved in the biocycling of elements important to soil productivity. Bradyrhizobium japonicum is a soil bacterium involved in symbiotic nitrogen fixation with Glycine max, the common soybean. To examine the effect of metal-rich sludge application on B. japonicum, the MICs for Pb, Cu, Al, Fe, Ni, Zn, Cd, and Hg were determined in minimal media by using laboratory reference strains representing 11 common serogroups of B. japonicum. Marked differences were found among the B. japonicum strains for sensitivity to Cu, Cd, Zn, and Ni. Strain USDA 123 was most sensitive to these metals, whereas strain USDA 122 was most resistant. In field studies, a silt loam soil amended 11 years ago with 0, 56, or 112 Mg of digested sludge per ha was examined for total numbers of B. japonicum by using the most probable number method. Nodule isolates from soybean nodules grown on this soil were serologically typed, and their metal sensitivity was determined. The number of soybean rhizobia in the sludge-amended soils was found to increase with increasing rates of sludge. Soybean rhizobia strains from 11 serogroups were identified in the soils; however, no differences in serogroup distribution or proportion of resistant strains were found between the soils. Thus, the application of heavy metal-containing sewage sludge did not have a long-term detrimental effect on soil rhizobial numbers, nor did it result in a shift in nodule serogroup distribution.

  20. Long-Term Effects of Metal-Rich Sewage Sludge Application on Soil Populations of Bradyrhizobium japonicum

    PubMed Central

    Kinkle, B. K.; Angle, J. S.; Keyser, H. H.

    1987-01-01

    The application of sewage sludge to land may increase the concentration of heavy metals in soil. Of considerable concern is the effect of heavy metals on soil microorganisms, especially those involved in the biocycling of elements important to soil productivity. Bradyrhizobium japonicum is a soil bacterium involved in symbiotic nitrogen fixation with Glycine max, the common soybean. To examine the effect of metal-rich sludge application on B. japonicum, the MICs for Pb, Cu, Al, Fe, Ni, Zn, Cd, and Hg were determined in minimal media by using laboratory reference strains representing 11 common serogroups of B. japonicum. Marked differences were found among the B. japonicum strains for sensitivity to Cu, Cd, Zn, and Ni. Strain USDA 123 was most sensitive to these metals, whereas strain USDA 122 was most resistant. In field studies, a silt loam soil amended 11 years ago with 0, 56, or 112 Mg of digested sludge per ha was examined for total numbers of B. japonicum by using the most probable number method. Nodule isolates from soybean nodules grown on this soil were serologically typed, and their metal sensitivity was determined. The number of soybean rhizobia in the sludge-amended soils was found to increase with increasing rates of sludge. Soybean rhizobia strains from 11 serogroups were identified in the soils; however, no differences in serogroup distribution or proportion of resistant strains were found between the soils. Thus, the application of heavy metal-containing sewage sludge did not have a long-term detrimental effect on soil rhizobial numbers, nor did it result in a shift in nodule serogroup distribution. PMID:16347281

  1. A Population-Based Study of Childhood Sexual Contact in China: Prevalence and Long-Term Consequences

    PubMed Central

    Luo, Ye; Parish, William L.; Laumann, Edward O.

    2008-01-01

    Objectives This study provides national estimates of the prevalence of childhood sexual contact and its association with sexual well-being and psychological distress among adults in China. Method A national stratified probability sample of 1,519 women and 1,475 men aged 20 to 64 years in urban China completed a computer-administered survey in 1999–2000. The data from this survey on both adult-to-child and peer-to-peer sexual contact before age 14 were subjected to descriptive and multivariate analyses that were adjusted for both sampling weights and sampling design. Results The overall prevalence of reported childhood sexual contact was 4.2%, with prevalence higher among men (5.1%) than among women (3.3%) and higher among those aged 20–29 years (8.3%). Childhood sexual contact was associated with multiplex consequences, including hyper-sexuality (high levels of masturbation, thoughts about sex, varieties of sexual practices, partner turnover), adult sexual victimization (unwanted sex, unwanted sexual acts, sexual harassment), sexual difficulties (genitor-urinary symptoms, sexually transmitted infections, sexual dysfunctions), and psychological distress. Psychological distress was largely mediated by adult sexual victimization, sexual difficulties, and hyper-sexuality. Conclusions Despite the relatively modest prevalence of childhood sexual contact among Chinese adults, the association with multiplex adult outcomes suggests that much as in the West early sexual contact is a significant issue. Practice Implications The findings underscore the importance of public education about childhood sexual contact and abuse in China. The findings suggest a need for public health campaigns that tackle the stigma associated with being abused and encourage victims to report abusive behavior to proper sources. The findings are also consistent with new efforts to alleviate the negative long-term impact of childhood sexual abuse. PMID:18614231

  2. Inexact fuzzy-stochastic mixed-integer programming approach for long-term planning of waste management--Part A: methodology.

    PubMed

    Guo, P; Huang, G H

    2009-01-01

    In this study, an inexact fuzzy chance-constrained two-stage mixed-integer linear programming (IFCTIP) approach is proposed for supporting long-term planning of waste-management systems under multiple uncertainties in the City of Regina, Canada. The method improves upon the existing inexact two-stage programming and mixed-integer linear programming techniques by incorporating uncertainties expressed as multiple uncertainties of intervals and dual probability distributions within a general optimization framework. The developed method can provide an effective linkage between the predefined environmental policies and the associated economic implications. Four special characteristics of the proposed method make it unique compared with other optimization techniques that deal with uncertainties. Firstly, it provides a linkage to predefined policies that have to be respected when a modeling effort is undertaken; secondly, it is useful for tackling uncertainties presented as intervals, probabilities, fuzzy sets and their incorporation; thirdly, it facilitates dynamic analysis for decisions of facility-expansion planning and waste-flow allocation within a multi-facility, multi-period, multi-level, and multi-option context; fourthly, the penalties are exercised with recourse against any infeasibility, which permits in-depth analyses of various policy scenarios that are associated with different levels of economic consequences when the promised solid waste-generation rates are violated. In a companion paper, the developed method is applied to a real case for the long-term planning of waste management in the City of Regina, Canada. PMID:19800164

  3. Inexact fuzzy-stochastic mixed-integer programming approach for long-term planning of waste management--Part A: methodology.

    PubMed

    Guo, P; Huang, G H

    2009-01-01

    In this study, an inexact fuzzy chance-constrained two-stage mixed-integer linear programming (IFCTIP) approach is proposed for supporting long-term planning of waste-management systems under multiple uncertainties in the City of Regina, Canada. The method improves upon the existing inexact two-stage programming and mixed-integer linear programming techniques by incorporating uncertainties expressed as multiple uncertainties of intervals and dual probability distributions within a general optimization framework. The developed method can provide an effective linkage between the predefined environmental policies and the associated economic implications. Four special characteristics of the proposed method make it unique compared with other optimization techniques that deal with uncertainties. Firstly, it provides a linkage to predefined policies that have to be respected when a modeling effort is undertaken; secondly, it is useful for tackling uncertainties presented as intervals, probabilities, fuzzy sets and their incorporation; thirdly, it facilitates dynamic analysis for decisions of facility-expansion planning and waste-flow allocation within a multi-facility, multi-period, multi-level, and multi-option context; fourthly, the penalties are exercised with recourse against any infeasibility, which permits in-depth analyses of various policy scenarios that are associated with different levels of economic consequences when the promised solid waste-generation rates are violated. In a companion paper, the developed method is applied to a real case for the long-term planning of waste management in the City of Regina, Canada.

  4. Paleoecological studies on variability in marine fish populations: A long-term perspective on the impacts of climatic change on marine ecosystems

    NASA Astrophysics Data System (ADS)

    Finney, Bruce P.; Alheit, Jürgen; Emeis, Kay-Christian; Field, David B.; Gutiérrez, Dimitri; Struck, Ulrich

    2010-02-01

    The use of historical fishing records to understand relationships between climatic change and fish abundance is limited by the relatively short duration of these records, and complications due to the strong influence of human activity in addition to climatic change. Sedimentary records containing scales, bones or geochemical proxies of variability in fish populations provide unique insights on long-term ecosystem dynamics and relationships with climatic change. Available records from Holocene sediments are summarized and synthesized. The records are from several widespread locations near or along the continental margins of the South Atlantic and Pacific oceans, including Alaska, USA (Pacific salmon), Saanich and Effingham Inlets, British Columbia, Canada (pelagic fish), Santa Barbara Basin, California, USA (Northern anchovies and Pacific sardines), Gulf of California, Mexico (Pacific sardines, Northern anchovies and Pacific hake), Peru upwelling system (sardines, anchovies and hake), and Benguela Current System, South Africa (sardines, anchovies and hake). These records demonstrate that fish population sizes are not constant, and varied significantly over a range of time scales prior to the advent of large-scale commercial fishing. In addition to the decadal-scale variability commonly observed in historical records, the long-term records reveal substantial variability over centennial and millennial time scales. Shifts in abundance are often, but not always, correlated with regional and/or global climatic changes. The long-term perspective reveals different patterns of variability in fish populations, as well as fish-climate relationships, than suggested by analysis of historical records. Many records suggest prominent changes in fish abundance at ca. 1000-1200 AD, during the Little Ice Age, and during the transition at the end of the Little Ice Age in the 19th century that may be correlative, and that were likely driven by major hemispheric or global

  5. Could residual oil from the Exxon Valdez spill create a long-term population "sink" for sea otters in Alaska?

    USGS Publications Warehouse

    Monson, D.H.; Doak, D.F.; Ballachey, B.E.; Bodkin, J.L.

    2011-01-01

    Over 20 years ago, the Exxon Valdez oil tanker spilled 42 million L of crude oil into the waters of Prince William Sound, Alaska, USA. At the time of the spill, the sea otter (Enhydra lutris) population inhabiting the spill area suffered substantial acute injuries and loss. Subsequent research has resulted in one of the best-studied species responses to an oil spill in history. However, the question remains: Is the spill still influencing the Prince William Sound sea otter population? Here we fit time-varying population models to data for the sea otter population of western Prince William Sound to quantify the duration and extent of mortality effects from the spill. We hypothesize that the patchy nature of residual oil left in the environment has created a source-sink population dynamic. We fit models using the age distributions of both living and dying animals and estimates of sea otter population size to predict the number of sea otters in the hypothesized sink population and the number lost to this sink due to chronic exposure to residual oil. Our results suggest that the sink population has remained at just over 900 individuals (95% CI: 606-960) between 1990 and 2009, during which time prime-age survival remained 2-6% below pre-spill levels. This reduced survival led to chronic losses of ???900 animals over the past two decades, which is similar in magnitude to the number of sea otter deaths documented in western Prince William Sound during the acute phase of the spill. However, the unaffected source population appears to be counterbalancing these losses, with the model indicating that the sea otter population increased from ???2150 individuals in 1990 to nearly 3000 in 2009. The most optimistic interpretation of our results suggests that mortality effects dissipated between 2005 and 2007. Our results suggest that residual oil can affect wildlife populations on time scales much longer than previously believed and that cumulative chronic effects can be as

  6. Long-term changes in human colonic Bifidobacterium populations induced by a 5-day oral amoxicillin-clavulanic acid treatment.

    PubMed

    Mangin, Irène; Lévêque, Christophe; Magne, Fabien; Suau, Antonia; Pochart, Philippe

    2012-01-01

    The objective of this study was to assess the possible modifications due to amoxicillin-clavulanic acid (AMC) treatment on total bacteria and on Bifidobacterium species balance in human colonic microbiota. Eighteen healthy volunteers (19 to 36 years old) were given a 875/125 mg dose of AMC twice a day for 5 days. Fecal samples were obtained before and after antibiotic exposure. After total DNA extraction, total bacteria and bifidobacteria were specifically quantified using real-time PCR. Dominant species were monitored over time using bacterial and bifidobacterial Temporal Temperature Gradient gel Electrophoresis (TTGE). At the end of AMC exposure, total bacterial concentrations as well as bifidobacteria concentrations were significantly reduced compared to before AMC exposure:10.7±0.1 log(10) 16S rRNA gene copies/g vs 11.1±0.1 log(10) (p = 0.003) and 8.1±0.5 log(10) 16S rRNA gene copies/g vs 9.4±0.3 log(10) (p = 0.003), respectively. At the same time, the mean similarity percentages of TTGE bacteria and TTGE bifidobacteria profiles were significantly reduced compared to before AMC exposure: 51.6%±3.5% vs 81.4%±2.1% and 55.8%±7.6% vs 84.5%±4.1%, respectively. Occurrence of B. adolescentis, B. bifidum and B. pseudocatenulatum/B. catenulatum species significantly decreased. Occurrence of B. longum remained stable. Moreover, the number of distinct Bifidobacterium species per sample significantly decreased (1.5±0.3 vs 2.3±0.3; p = 0.01). Two months after AMC exposure, the mean similarity percentage of TTGE profiles was 55.6% for bacteria and 62.3% for bifidobacteria. These results clearly demonstrated that a common antibiotic treatment may qualitatively alter the colonic microbiota. Such modifications may have potential long-term physiological consequences.

  7. Does human-induced hybridization have long-term genetic effects? Empirical testing with domesticated, wild and hybridized fish populations

    PubMed Central

    Harbicht, Andrew; Wilson, Chris C; Fraser, Dylan J

    2014-01-01

    Current conservation practices exclude human-generated hybridized populations from protection, as the genetic effects of hybridization in the wild have been observed to be long-lasting based on neutral genetic markers and are considered potentially irreversible. Theory, however, predicts otherwise for genes under selection. We transplanted combinations of wild, domesticated and hybridized populations of a fish species to new environments. We then compared survival, phenotypic variation and plasticity to determine whether hybridization affects adaptive potential after multiple generations of selection in the wild. Although the fitness of our hybridized populations at the onset of hybridization cannot be assessed, our results suggest that within five to eleven generations, selection can remove introduced foreign genes from wild populations that have hybridized with domesticated conspecifics. The end result is hybridized populations that, in terms of survival, phenotypic plasticity, mean trait expression and overall general responses to environmental change, closely resemble neighbouring wild populations. These results have important implications for considering the potential conservation value of hybridized populations and illustrate the effectiveness of selection in a local environment. PMID:25558279

  8. Long-term effects of translocation and release numbers on fine-scale population structure among coho salmon (Oncorhynchus kisutch).

    PubMed

    Eldridge, William H; Naish, Kerry A

    2007-06-01

    Management actions, such as translocations, reintroductions and supportive breeding, can have both negative and positive effects on population recovery. Several studies have examined the incidence of introgression following such actions, but few studies have explored the effect of release numbers on gene flow between closely related recipient populations. We examined population structure of coho salmon in Puget Sound (Washington State, USA) to evaluate the relationship between the number of individuals transferred between rivers, and the number released within rivers, on inter- and intrariver population divergence. Eleven microsatellite loci were surveyed in 23 hatchery and wild samples collected from 11 rivers within and one hatchery outside Puget Sound. Pairwise genetic divergences between most populations were significant, but the population structure could not be explained by an isolation-by-distance model (Mantel test, P > 0.05). In contrast, we detected significant hatchery influence on population structure. The numbers of fish transferred among rivers between 1952 and 2004 was negatively correlated with differentiation between rivers (partial Mantel test, P = 0.005) but not within rivers (t-test, P = 0.41). Number of fish released from hatcheries that collect broodstock locally was negatively correlated with population structure within rivers (t-test P = 0.002), and between nearby rivers (partial Mantel P = 0.04). Our results indicate that the population structure can, to some degree, be altered by the number of individuals transferred and by local release number of individuals in ongoing artificial propagation programs. The findings presented here emphasize the need to control the number of individuals that are either inadvertently introduced, or are deliberately released under conservation scenarios.

  9. Landscape resistance to dispersal: Predicting long-term effects for a small and isolated wolf population in southwestern Manitoba, Canada

    EPA Science Inventory

    Landscape fragmentation affects wildlife population viability, in part through the effects it has on individual dispersal. Considerable fragmentation of native habitats and loss of forest cover has occurred in association with agricultural development over the past 50 years in o...

  10. Long-term monitoring of feral genetically modified herbicide-tolerant Brassica napus populations around unloading Japanese ports

    PubMed Central

    Katsuta, Kensuke; Matsuo, Kazuhito; Yoshimura, Yasuyuki; Ohsawa, Ryo

    2015-01-01

    Genetically modified, herbicide-tolerant (GMHT) Brassica napus plants originating from seed spill have recently been found along roadsides leading from Japanese ports that unload oilseed rape. Such introductions have potential biodiversity effects (as defined by the Cartagena Protocol): these include replacement of native elements in the biota through competitive suppression or hybridization. We conducted surveys in the period 2006–2011 to assess such threats. We examined shifts in the population distribution and occurrence of GMHT plants in 1,029 volunteer introduced assemblages of B. napus, 1,169 of B. juncea, and 184 of B. rapa around 12 ports. GMHT B. napus was found around 10 of 12 ports, but its proportion in the populations varied greatly by year and location. Over the survey period, the distributions of a pure non-GMHT population around Tobata and a pure GMHT population around Hakata increased significantly. However, there was no common trend of population expansion or contraction around the 12 ports. Furthermore, we found no herbicide tolerant B. juncea and B. rapa plants derived from crosses with GMHT B. napus. Therefore, GMHT B. napus is not invading native vegetation surrounding its populations and not likely to cross with congeners in Japanese environment. PMID:26175624

  11. Long-term monitoring of feral genetically modified herbicide-tolerant Brassica napus populations around unloading Japanese ports.

    PubMed

    Katsuta, Kensuke; Matsuo, Kazuhito; Yoshimura, Yasuyuki; Ohsawa, Ryo

    2015-06-01

    Genetically modified, herbicide-tolerant (GMHT) Brassica napus plants originating from seed spill have recently been found along roadsides leading from Japanese ports that unload oilseed rape. Such introductions have potential biodiversity effects (as defined by the Cartagena Protocol): these include replacement of native elements in the biota through competitive suppression or hybridization. We conducted surveys in the period 2006-2011 to assess such threats. We examined shifts in the population distribution and occurrence of GMHT plants in 1,029 volunteer introduced assemblages of B. napus, 1,169 of B. juncea, and 184 of B. rapa around 12 ports. GMHT B. napus was found around 10 of 12 ports, but its proportion in the populations varied greatly by year and location. Over the survey period, the distributions of a pure non-GMHT population around Tobata and a pure GMHT population around Hakata increased significantly. However, there was no common trend of population expansion or contraction around the 12 ports. Furthermore, we found no herbicide tolerant B. juncea and B. rapa plants derived from crosses with GMHT B. napus. Therefore, GMHT B. napus is not invading native vegetation surrounding its populations and not likely to cross with congeners in Japanese environment. PMID:26175624

  12. Long-term monitoring of feral genetically modified herbicide-tolerant Brassica napus populations around unloading Japanese ports.

    PubMed

    Katsuta, Kensuke; Matsuo, Kazuhito; Yoshimura, Yasuyuki; Ohsawa, Ryo

    2015-06-01

    Genetically modified, herbicide-tolerant (GMHT) Brassica napus plants originating from seed spill have recently been found along roadsides leading from Japanese ports that unload oilseed rape. Such introductions have potential biodiversity effects (as defined by the Cartagena Protocol): these include replacement of native elements in the biota through competitive suppression or hybridization. We conducted surveys in the period 2006-2011 to assess such threats. We examined shifts in the population distribution and occurrence of GMHT plants in 1,029 volunteer introduced assemblages of B. napus, 1,169 of B. juncea, and 184 of B. rapa around 12 ports. GMHT B. napus was found around 10 of 12 ports, but its proportion in the populations varied greatly by year and location. Over the survey period, the distributions of a pure non-GMHT population around Tobata and a pure GMHT population around Hakata increased significantly. However, there was no common trend of population expansion or contraction around the 12 ports. Furthermore, we found no herbicide tolerant B. juncea and B. rapa plants derived from crosses with GMHT B. napus. Therefore, GMHT B. napus is not invading native vegetation surrounding its populations and not likely to cross with congeners in Japanese environment.

  13. Inexact fuzzy-stochastic mixed integer programming approach for long-term planning of waste management---Part B: case study.

    PubMed

    Guo, P; Huang, G H

    2009-01-01

    In this study, a solid waste decision-support system was developed for the long-term planning of waste management in the City of Regina, Canada. Interactions among various system components, objectives, and constraints will be analyzed. Issues concerning planning for cost-effective diversion and prolongation of the landfill will be addressed. Decisions of system-capacity expansion and waste allocation within a multi-facility, multi-option, and multi-period context will be obtained. The obtained results would provide useful information and decision-support for the City's solid waste management and planning. In the application, four scenarios are considered. Through the above scenario analyses under different waste-management policies, useful decision support for the City's solid waste managers and decision makers was generated. Analyses for the effects of varied policies (for allowable waste flows to different facilities) under 35 and 50% diversion goals were also undertaken. Tradeoffs among system cost and constraint-violation risk were analyzed. Generally, a policy with lower allowable waste-flow levels corresponded to a lower system cost under advantageous conditions but, at the same time, a higher penalty when such allowances were violated. A policy with higher allowable flow levels corresponded to a higher cost under disadvantageous conditions. The modeling results were useful for (i) scheduling adequate time and capacity for long-term planning of the facility development and/or expansion in the city's waste management system, (ii) adjusting of the existing waste flow allocation patterns to satisfy the city's diversion goal, and (iii) generating of desired policies for managing the city's waste generation, collection and disposal. PMID:19818549

  14. Reduced flight-to-light behaviour of moth populations exposed to long-term urban light pollution.

    PubMed

    Altermatt, Florian; Ebert, Dieter

    2016-04-01

    The globally increasing light pollution is a well-recognized threat to ecosystems, with negative effects on human, animal and plant wellbeing. The most well-known and widely documented consequence of light pollution is the generally fatal attraction of nocturnal insects to artificial light sources. However, the evolutionary consequences are unknown. Here we report that moth populations from urban areas with high, globally relevant levels of light pollution over several decades show a significantly reduced flight-to-light behaviour compared with populations of the same species from pristine dark-sky habitats. Using a common garden setting, we reared moths from 10 different populations from early-instar larvae and experimentally compared their flight-to-light behaviour under standardized conditions. Moths from urban populations had a significant reduction in the flight-to-light behaviour compared with pristine populations. The reduced attraction to light sources of 'city moths' may directly increase these individuals' survival and reproduction. We anticipate that it comes with a reduced mobility, which negatively affects foraging as well as colonization ability. As nocturnal insects are of eminent significance as pollinators and the primary food source of many vertebrates, an evolutionary change of the flight-to-light behaviour thereby potentially cascades across species interaction networks. PMID:27072407

  15. Predicting the effects of human developments on individual dolphins to understand potential long-term population consequences.

    PubMed

    Pirotta, Enrico; Harwood, John; Thompson, Paul M; New, Leslie; Cheney, Barbara; Arso, Monica; Hammond, Philip S; Donovan, Carl; Lusseau, David

    2015-11-01

    Human activities that impact wildlife do not necessarily remove individuals from populations. They may also change individual behaviour in ways that have sublethal effects. This has driven interest in developing analytical tools that predict the population consequences of short-term behavioural responses. In this study, we incorporate empirical information on the ecology of a population of bottlenose dolphins into an individual-based model that predicts how individuals' behavioural dynamics arise from their underlying motivational states, as well as their interaction with boat traffic and dredging activities. We simulate the potential effects of proposed coastal developments on this population and predict that the operational phase may affect animals' motivational states. For such results to be relevant for management, the effects on individuals' vital rates also need to be quantified. We investigate whether the relationship between an individual's exposure and the survival of its calves can be directly estimated using a Bayesian multi-stage model for calf survival. The results suggest that any effect on calf survival is probably small and that a significant relationship could only be detected in large, closely studied populations. Our work can be used to guide management decisions, accelerate the consenting process for coastal and offshore developments and design targeted monitoring. PMID:26511044

  16. Reduced flight-to-light behaviour of moth populations exposed to long-term urban light pollution.

    PubMed

    Altermatt, Florian; Ebert, Dieter

    2016-04-01

    The globally increasing light pollution is a well-recognized threat to ecosystems, with negative effects on human, animal and plant wellbeing. The most well-known and widely documented consequence of light pollution is the generally fatal attraction of nocturnal insects to artificial light sources. However, the evolutionary consequences are unknown. Here we report that moth populations from urban areas with high, globally relevant levels of light pollution over several decades show a significantly reduced flight-to-light behaviour compared with populations of the same species from pristine dark-sky habitats. Using a common garden setting, we reared moths from 10 different populations from early-instar larvae and experimentally compared their flight-to-light behaviour under standardized conditions. Moths from urban populations had a significant reduction in the flight-to-light behaviour compared with pristine populations. The reduced attraction to light sources of 'city moths' may directly increase these individuals' survival and reproduction. We anticipate that it comes with a reduced mobility, which negatively affects foraging as well as colonization ability. As nocturnal insects are of eminent significance as pollinators and the primary food source of many vertebrates, an evolutionary change of the flight-to-light behaviour thereby potentially cascades across species interaction networks.

  17. Application of a Systems Pharmacology-Based Placebo Population Model to Analyze Long-Term Data of Postmenopausal Osteoporosis.

    PubMed

    Berkhout, J; Stone, J A; Verhamme, K M; Stricker, B H; Sturkenboom, M C; Danhof, M; Post, T M

    2015-09-01

    Osteoporosis is a progressive bone disease characterized by decreased bone mass resulting in increased fracture risk. The objective of this investigation was to test whether a recently developed disease systems analysis model for osteoporosis could describe disease progression in a placebo-treated population from the Early Postmenopausal Intervention Cohort (EPIC) study. First, we qualified the model using a subset from the placebo arm of the EPIC study of 222 women who had similar demographic characteristics as the 149 women from the placebo arm of the original population. Second, we applied the model to all 470 women. Bone mineral density (BMD) dynamics were changed to an indirect response model to describe lumbar spine and total hip BMD in this second population. This updated disease systems analysis placebo model describes the dynamics of all biomarkers in the corresponding datasets to a very good approximation; a good description of an individual placebo response will be valuable for evaluating treatments for osteoporosis.

  18. Second Cancers After Fractionated Radiotherapy: Stochastic Population Dynamics Effects

    NASA Technical Reports Server (NTRS)

    Sachs, Rainer K.; Shuryak, Igor; Brenner, David; Fakir, Hatim; Hahnfeldt, Philip

    2007-01-01

    When ionizing radiation is used in cancer therapy it can induce second cancers in nearby organs. Mainly due to longer patient survival times, these second cancers have become of increasing concern. Estimating the risk of solid second cancers involves modeling: because of long latency times, available data is usually for older, obsolescent treatment regimens. Moreover, modeling second cancers gives unique insights into human carcinogenesis, since the therapy involves administering well characterized doses of a well studied carcinogen, followed by long-term monitoring. In addition to putative radiation initiation that produces pre-malignant cells, inactivation (i.e. cell killing), and subsequent cell repopulation by proliferation can be important at the doses relevant to second cancer situations. A recent initiation/inactivation/proliferation (IIP) model characterized quantitatively the observed occurrence of second breast and lung cancers, using a deterministic cell population dynamics approach. To analyze ifradiation-initiated pre-malignant clones become extinct before full repopulation can occur, we here give a stochastic version of this I I model. Combining Monte Carlo simulations with standard solutions for time-inhomogeneous birth-death equations, we show that repeated cycles of inactivation and repopulation, as occur during fractionated radiation therapy, can lead to distributions of pre-malignant cells per patient with variance >> mean, even when pre-malignant clones are Poisson-distributed. Thus fewer patients would be affected, but with a higher probability, than a deterministic model, tracking average pre-malignant cell numbers, would predict. Our results are applied to data on breast cancers after radiotherapy for Hodgkin disease. The stochastic IIP analysis, unlike the deterministic one, indicates: a) initiated, pre-malignant cells can have a growth advantage during repopulation, not just during the longer tumor latency period that follows; b) weekend

  19. Increasing cell culture population doublings for long-term growth of finite life span human cell cultures

    DOEpatents

    Stampfer, Martha R.; Garbe, James C.

    2016-06-28

    Cell culture media formulations for culturing human epithelial cells are herein described. Also described are methods of increasing population doublings in a cell culture of finite life span human epithelial cells and prolonging the life span of human cell cultures. Using the cell culture media disclosed alone and in combination with addition to the cell culture of a compound associated with anti-stress activity achieves extended growth of pre-stasis cells and increased population doublings and life span in human epithelial cell cultures.

  20. Increasing cell culture population doublings for long-term growth of finite life span human cell cultures

    SciTech Connect

    Stampfer, Martha R; Garbe, James C

    2015-02-24

    Cell culture media formulations for culturing human epithelial cells are herein described. Also described are methods of increasing population doublings in a cell culture of finite life span human epithelial cells and prolonging the life span of human cell cultures. Using the cell culture media disclosed alone and in combination with addition to the cell culture of a compound associated with anti-stress activity achieves extended growth of pre-stasis cells and increased population doublings and life span in human epithelial cell cultures.

  1. Long-term survival after coronary bypass surgery. Comparison of various subsets of patients with general population.

    PubMed Central

    Greene, D G; Bunnell, I L; Arani, D T; Schimert, G; Lajos, T Z; Lee, A B; Tandon, R N; Zimdahl, W T; Bozer, J M; Kohn, R M; Visco, J P; Dean, D C; Smith, G L

    1981-01-01

    Life-table analysis consecutive cases of isolated coronary bypass surgery at the Buffalo Hospital between 1973 and 1977 showed an estimated survival of 94 per cent at five years, equal to that of an age- and sex-matched group of the US population. Subsets of these patients divided according to sex, age, number of vessels narrowed, number of segments grafted, history of myocardial infarction, ejection fraction, and presence of unstable angina have estimated survivals not statistically less in any of these subsets than that of matched cohorts of the general population. PMID:6971646

  2. A long-term study of Rattus norvegicus in the London borough of Enfield using baiting returns as an indicator of sewer population levels.

    PubMed Central

    Channon, D.; Cole, M.; Cole, L.

    2000-01-01

    This is a long-term study that investigates the dynamics of a population of Rattus norvegicus (Berk) inhabiting a sewerage system in London. Thirteen years (1986/7-1998/9) of data from sewer baiting records were analysed (a total of 35,478 records). Manholes were baited with the anticoagulant Brodifacoum (0.005%) on a pinhead oatmeal bait base. Time series analysis was conducted on the data set to determine the underlying trend of the data and the population fluctuations about this trend. An exponential curve was found to give an accurate and realistic fit to the data and indicated that the rat population had decreased over the study period. Decomposition analysis indicated a 5-year cycle best described fluctuations around this trend. PMID:11117969

  3. Secondary Surge Capacity: A Framework for Understanding Long-Term Access to Primary Care for Medically Vulnerable Populations in Disaster Recovery

    PubMed Central

    Brock-Martin, Amy; Karmaus, Wilfried; Svendsen, Erik R.

    2012-01-01

    Disasters create a secondary surge in casualties because of the sudden increased need for long-term health care. Surging demands for medical care after a disaster place excess strain on an overtaxed health care system operating at maximum or reduced capacity. We have applied a health services use model to identify areas of vulnerability that perpetuate health disparities for at-risk populations seeking care after a disaster. We have proposed a framework to understand the role of the medical system in modifying the health impact of the secondary surge on vulnerable populations. Baseline assessment of existing needs and the anticipation of ballooning chronic health care needs following the acute response for at-risk populations are overlooked vulnerability gaps in national surge capacity plans. PMID:23078479

  4. Alcohol Habits in Patients with Long-Term Musculoskeletal Pain: Comparison with a Matched Control Group from the General Population

    ERIC Educational Resources Information Center

    Thelin Bronner, Kerstin Birgitta; Wennberg, Peter; Kallmen, Hakan; Schult, Marie-Louise Birgitta

    2012-01-01

    This prospective study aimed to describe alcohol habits in patients with chronic pain compared with those in a matched control group from the general Swedish population. In total, 100 consecutive patients enrolled were matched against 100 individuals in a control group on the basis of age and sex. Alcohol habits were measured using the Alcohol Use…

  5. Understanding the contribution of habitats and regional variation to long-term population trends in tricolored blackbirds.

    PubMed

    Graves, Emily E; Holyoak, Marcel; Rodd Kelsey, T; Meese, Robert J

    2013-09-01

    Population trends represent a minimum amount of information required to assess the conservation status of a species. However, understanding and detecting trends can be complicated by variation among habitats and regions, and by dispersal connecting habitats through source-sink dynamics. We analyzed trends in breeding populations between habitats and regions to better understand the overall dynamics of a species' decline. Specifically, we analyzed historical trends in breeding populations of tricolored blackbirds (Agelaius tricolor) using breeding records from 1907 to 2009. The species breeds itinerantly and ephemerally uses multiple habitat types and breeding areas, which make interpretation of trends complex. We found overall abundance declines of 63% between 1935 and 1975. Since 1980 overall declines became nonsignificant and obscure despite large amounts of data from 1980 to 2009. Temporal trends differed between breeding habitat types and were associated with regional differences in population declines. A new habitat, triticale crops (a wheat-rye hybrid grain) produced colonies 40× larger, on average, than other breeding habitats, and contributed to a change in regional distribution since it primarily occurred in a single region. The mechanism for such an effect is not clear, but could represent the local availability of foodstuffs in the landscape rather than something specific to triticale crops. While variation in trends among habitats clearly occurred, they could not easily be ascribed to source-sink dynamics, ecological traps, habitat selection or other detailed ecological mechanisms. Nonetheless, such exchanges provide valuable information to guide management of dynamic systems.

  6. Understanding the contribution of habitats and regional variation to long-term population trends in tricolored blackbirds

    PubMed Central

    Graves, Emily E; Holyoak, Marcel; Rodd Kelsey, T; Meese, Robert J

    2013-01-01

    Population trends represent a minimum amount of information required to assess the conservation status of a species. However, understanding and detecting trends can be complicated by variation among habitats and regions, and by dispersal connecting habitats through source-sink dynamics. We analyzed trends in breeding populations between habitats and regions to better understand the overall dynamics of a species' decline. Specifically, we analyzed historical trends in breeding populations of tricolored blackbirds (Agelaius tricolor) using breeding records from 1907 to 2009. The species breeds itinerantly and ephemerally uses multiple habitat types and breeding areas, which make interpretation of trends complex. We found overall abundance declines of 63% between 1935 and 1975. Since 1980 overall declines became nonsignificant and obscure despite large amounts of data from 1980 to 2009. Temporal trends differed between breeding habitat types and were associated with regional differences in population declines. A new habitat, triticale crops (a wheat-rye hybrid grain) produced colonies 40× larger, on average, than other breeding habitats, and contributed to a change in regional distribution since it primarily occurred in a single region. The mechanism for such an effect is not clear, but could represent the local availability of foodstuffs in the landscape rather than something specific to triticale crops. While variation in trends among habitats clearly occurred, they could not easily be ascribed to source-sink dynamics, ecological traps, habitat selection or other detailed ecological mechanisms. Nonetheless, such exchanges provide valuable information to guide management of dynamic systems. PMID:24101977

  7. Understanding the contribution of habitats and regional variation to long-term population trends in tricolored blackbirds.

    PubMed

    Graves, Emily E; Holyoak, Marcel; Rodd Kelsey, T; Meese, Robert J

    2013-09-01

    Population trends represent a minimum amount of information required to assess the conservation status of a species. However, understanding and detecting trends can be complicated by variation among habitats and regions, and by dispersal connecting habitats through source-sink dynamics. We analyzed trends in breeding populations between habitats and regions to better understand the overall dynamics of a species' decline. Specifically, we analyzed historical trends in breeding populations of tricolored blackbirds (Agelaius tricolor) using breeding records from 1907 to 2009. The species breeds itinerantly and ephemerally uses multiple habitat types and breeding areas, which make interpretation of trends complex. We found overall abundance declines of 63% between 1935 and 1975. Since 1980 overall declines became nonsignificant and obscure despite large amounts of data from 1980 to 2009. Temporal trends differed between breeding habitat types and were associated with regional differences in population declines. A new habitat, triticale crops (a wheat-rye hybrid grain) produced colonies 40× larger, on average, than other breeding habitats, and contributed to a change in regional distribution since it primarily occurred in a single region. The mechanism for such an effect is not clear, but could represent the local availability of foodstuffs in the landscape rather than something specific to triticale crops. While variation in trends among habitats clearly occurred, they could not easily be ascribed to source-sink dynamics, ecological traps, habitat selection or other detailed ecological mechanisms. Nonetheless, such exchanges provide valuable information to guide management of dynamic systems. PMID:24101977

  8. Risk of death from cardiovascular disease associated with low-level arsenic exposure among long-term smokers in a US population-based study.

    PubMed

    Farzan, Shohreh F; Chen, Yu; Rees, Judy R; Zens, M Scot; Karagas, Margaret R

    2015-09-01

    High levels of arsenic exposure have been associated with increases in cardiovascular disease risk. However, studies of arsenic's effects at lower exposure levels are limited and few prospective studies exist in the United States using long-term arsenic exposure biomarkers. We conducted a prospective analysis of the association between toenail arsenic and cardiovascular disease mortality using longitudinal data collected on 3939 participants in the New Hampshire Skin Cancer Study. Using Cox proportional hazard models adjusted for potential confounders, we estimated hazard ratios and 95% confidence intervals associated with the risk of death from any cardiovascular disease, ischemic heart disease, and stroke, in relation to natural-log transformed toenail arsenic concentrations. In this US population, although we observed no overall association, arsenic exposure measured from toenail clipping samples was related to an increased risk of ischemic heart disease mortality among long-term smokers (as reported at baseline), with increased hazard ratios among individuals with ≥ 31 total smoking years (HR: 1.52, 95% CI: 1.02, 2.27), ≥ 30 pack-years (HR: 1.66, 95% CI: 1.12, 2.45), and among current smokers (HR: 1.69, 95% CI: 1.04, 2.75). These results are consistent with evidence from more highly exposed populations suggesting a synergistic relationship between arsenic exposure and smoking on health outcomes and support a role for lower-level arsenic exposure in ischemic heart disease mortality.

  9. Mid- and long-term effects of family constellation seminars in a general population sample: 8- and 12-month follow-up.

    PubMed

    Hunger, Christina; Weinhold, Jan; Bornhäuser, Annette; Link, Leoni; Schweitzer, Jochen

    2015-06-01

    In a previous randomized controlled trial (RCT), short-term efficacy of family constellation seminars (FCSs) in a general population sample was demonstrated. In this article, we examined mid- and long-term stability of these effects. Participants were 104 adults (M = 47 years; SD = 9; 84% female) who were part of the intervention group in the original RCT (3-day FCS; 64 active participants and 40 observing participants). FCSs were carried out according to manuals. It was predicted that FCSs would improve psychological functioning (Outcome Questionnaire OQ-45.2) at 8- and 12-month follow-up. Additionally, we assessed the effects of FCSs on psychological distress, motivational incongruence, individuals' experience in their personal social systems, and overall goal attainment. Participants yielded significant improvement in psychological functioning (d = 0.41 at 8-month follow-up, p = .000; d = 0.40 at 12-month follow-up, p = .000). Results were confirmed for psychological distress, motivational incongruence, the participants' experience in their personal social systems, and overall goal attainment. No adverse events were reported. This study provides first evidence for the mid- and long-term efficacy of FCSs in a nonclinical population. The implications of the findings are discussed.

  10. In a long-term experimental demography study, excluding ungulates reversed invader's explosive population growth rate and restored natives.

    PubMed

    Kalisz, Susan; Spigler, Rachel B; Horvitz, Carol C

    2014-03-25

    A major goal in ecology is to understand mechanisms that increase invasion success of exotic species. A recent hypothesis implicates altered species interactions resulting from ungulate herbivore overabundance as a key cause of exotic plant domination. To test this hypothesis, we maintained an experimental demography deer exclusion study for 6 y in a forest where the native ungulate Odocoileus virginianus (white-tailed deer) is overabundant and Alliaria petiolata (garlic mustard) is aggressively invading. Because population growth is multiplicative across time, we introduce metrics that correctly integrate experimental effects across treatment years, the cumulative population growth rate, λc, and its geometric mean, λper-year, the time-averaged annual population growth rate. We determined λc and λper-year of the invader and of a common native, Trillium erectum. Our results conclusively demonstrate that deer are required for the success of Alliaria; its projected population trajectory shifted from explosive growth in the presence of deer (λper-year = 1.33) to decline toward extinction where deer are excluded (λper-year = 0.88). In contrast, Trillium's λper-year was suppressed in the presence of deer relative to deer exclusion (λper-year = 1.04 vs. 1.20, respectively). Retrospective sensitivity analyses revealed that the largest negative effect of deer exclusion on Alliaria came from rosette transitions, whereas the largest positive effect on Trillium came from reproductive transitions. Deer exclusion lowered Alliaria density while increasing Trillium density. Our results provide definitive experimental support that interactions with overabundant ungulates enhance demographic success of invaders and depress natives' success, with broad implications for biodiversity and ecosystem function worldwide.

  11. The influence of predator--prey population dynamics on the long-term evolution of food web structure.

    PubMed

    Drossel, B; Higgs, P G; McKane, A J

    2001-01-01

    We develop a set of equations to describe the population dynamics of many interacting species in food webs. Predator-prey interactions are nonlinear, and are based on ratio-dependent functional responses. The equations account for competition for resources between members of the same species, and between members of different species. Predators divide their total hunting/foraging effort between the available prey species according to an evolutionarily stable strategy (ESS). The ESS foraging behaviour does not correspond to the predictions of optimal foraging theory. We use the population dynamics equations in simulations of the Webworld model of evolving ecosystems. New species are added to an existing food web due to speciation events, whilst species become extinct due to coevolution and competition. We study the dynamics of species-diversity in Webworld on a macro-evolutionary time-scale. Coevolutionary interactions are strong enough to cause continuous overturn of species, in contrast to our previous Webworld simulations with simpler population dynamics. Although there are significant fluctuations in species diversity because of speciation and extinction, very large-scale extinction avalanches appear to be absent from the dynamics, and we find no evidence for self-organized criticality.

  12. Long-term assessment of wild boar harvesting and cattle removal for bovine tuberculosis control in free ranging populations.

    PubMed

    Mentaberre, Gregorio; Romero, Beatriz; de Juan, Lucía; Navarro-González, Nora; Velarde, Roser; Mateos, Ana; Marco, Ignasi; Olivé-Boix, Xavier; Domínguez, Lucas; Lavín, Santiago; Serrano, Emmanuel

    2014-01-01

    Wild boar is a recognized reservoir of bovine tuberculosis (TB) in the Mediterranean ecosystems, but information is scarce outside of hotspots in southern Spain. We describe the first high-prevalence focus of TB in a non-managed wild boar population in northern Spain and the result of eight years of TB management. Measures implemented for disease control included the control of the local wild boar population through culling and stamping out of a sympatric infected cattle herd. Post-mortem inspection for detection of tuberculosis-like lesions as well as cultures from selected head and cervical lymph nodes was done in 745 wild boar, 355 Iberian ibexes and five cattle between 2004 and 2012. The seasonal prevalence of TB reached 70% amongst adult wild boar and ten different spoligotypes and 13 MIRU-VNTR profiles were detected, although more than half of the isolates were included in the same clonal complex. Only 11% of infected boars had generalized lesions. None of the ibexes were affected, supporting their irrelevance in the epidemiology of TB. An infected cattle herd grazed the zone where 168 of the 197 infected boars were harvested. Cattle removal and wild boar culling together contributed to a decrease in TB prevalence. The need for holistic, sustained over time, intensive and adapted TB control strategies taking into account the multi-host nature of the disease is highlighted. The potential risk for tuberculosis emergence in wildlife scenarios where the risk is assumed to be low should be addressed. PMID:24558435

  13. Competing pressures on populations: long-term dynamics of food availability, food quality, disease, stress and animal abundance.

    PubMed

    Chapman, Colin A; Schoof, Valérie A M; Bonnell, Tyler R; Gogarten, Jan F; Calmé, Sophie

    2015-05-26

    Despite strong links between sociality and fitness that ultimately affect the size of animal populations, the particular social and ecological factors that lead to endangerment are not well understood. Here, we synthesize approximately 25 years of data and present new analyses that highlight dynamics in forest composition, food availability, the nutritional quality of food, disease, physiological stress and population size of endangered folivorous red colobus monkeys (Procolobus rufomitratus). There is a decline in the quality of leaves 15 and 30 years following two previous studies in an undisturbed area of forest. The consumption of a low-quality diet in one month was associated with higher glucocorticoid levels in the subsequent month and stress levels in groups living in degraded forest fragments where diet was poor was more than twice those in forest groups. In contrast, forest composition has changed and when red colobus food availability was weighted by the protein-to-fibre ratio, which we have shown positively predicts folivore biomass, there was an increase in the availability of high-quality trees. Despite these changing social and ecological factors, the abundance of red colobus has remained stable, possibly through a combination of increasing group size and behavioural flexibility.

  14. Competing pressures on populations: long-term dynamics of food availability, food quality, disease, stress and animal abundance.

    PubMed

    Chapman, Colin A; Schoof, Valérie A M; Bonnell, Tyler R; Gogarten, Jan F; Calmé, Sophie

    2015-05-26

    Despite strong links between sociality and fitness that ultimately affect the size of animal populations, the particular social and ecological factors that lead to endangerment are not well understood. Here, we synthesize approximately 25 years of data and present new analyses that highlight dynamics in forest composition, food availability, the nutritional quality of food, disease, physiological stress and population size of endangered folivorous red colobus monkeys (Procolobus rufomitratus). There is a decline in the quality of leaves 15 and 30 years following two previous studies in an undisturbed area of forest. The consumption of a low-quality diet in one month was associated with higher glucocorticoid levels in the subsequent month and stress levels in groups living in degraded forest fragments where diet was poor was more than twice those in forest groups. In contrast, forest composition has changed and when red colobus food availability was weighted by the protein-to-fibre ratio, which we have shown positively predicts folivore biomass, there was an increase in the availability of high-quality trees. Despite these changing social and ecological factors, the abundance of red colobus has remained stable, possibly through a combination of increasing group size and behavioural flexibility. PMID:25870398

  15. Long-Term Assessment of Wild Boar Harvesting and Cattle Removal for Bovine Tuberculosis Control in Free Ranging Populations

    PubMed Central

    Mentaberre, Gregorio; Romero, Beatriz; de Juan, Lucía; Navarro-González, Nora; Velarde, Roser; Mateos, Ana; Marco, Ignasi; Olivé-Boix, Xavier; Domínguez, Lucas; Lavín, Santiago; Serrano, Emmanuel

    2014-01-01

    Wild boar is a recognized reservoir of bovine tuberculosis (TB) in the Mediterranean ecosystems, but information is scarce outside of hotspots in southern Spain. We describe the first high-prevalence focus of TB in a non-managed wild boar population in northern Spain and the result of eight years of TB management. Measures implemented for disease control included the control of the local wild boar population through culling and stamping out of a sympatric infected cattle herd. Post-mortem inspection for detection of tuberculosis-like lesions as well as cultures from selected head and cervical lymph nodes was done in 745 wild boar, 355 Iberian ibexes and five cattle between 2004 and 2012. The seasonal prevalence of TB reached 70% amongst adult wild boar and ten different spoligotypes and 13 MIRU-VNTR profiles were detected, although more than half of the isolates were included in the same clonal complex. Only 11% of infected boars had generalized lesions. None of the ibexes were affected, supporting their irrelevance in the epidemiology of TB. An infected cattle herd grazed the zone where 168 of the 197 infected boars were harvested. Cattle removal and wild boar culling together contributed to a decrease in TB prevalence. The need for holistic, sustained over time, intensive and adapted TB control strategies taking into account the multi-host nature of the disease is highlighted. The potential risk for tuberculosis emergence in wildlife scenarios where the risk is assumed to be low should be addressed. PMID:24558435

  16. Competing pressures on populations: long-term dynamics of food availability, food quality, disease, stress and animal abundance

    PubMed Central

    Chapman, Colin A.; Schoof, Valérie A. M.; Bonnell, Tyler R.; Gogarten, Jan F.; Calmé, Sophie

    2015-01-01

    Despite strong links between sociality and fitness that ultimately affect the size of animal populations, the particular social and ecological factors that lead to endangerment are not well understood. Here, we synthesize approximately 25 years of data and present new analyses that highlight dynamics in forest composition, food availability, the nutritional quality of food, disease, physiological stress and population size of endangered folivorous red colobus monkeys (Procolobus rufomitratus). There is a decline in the quality of leaves 15 and 30 years following two previous studies in an undisturbed area of forest. The consumption of a low-quality diet in one month was associated with higher glucocorticoid levels in the subsequent month and stress levels in groups living in degraded forest fragments where diet was poor was more than twice those in forest groups. In contrast, forest composition has changed and when red colobus food availability was weighted by the protein-to-fibre ratio, which we have shown positively predicts folivore biomass, there was an increase in the availability of high-quality trees. Despite these changing social and ecological factors, the abundance of red colobus has remained stable, possibly through a combination of increasing group size and behavioural flexibility. PMID:25870398

  17. Long-term fluctuations in Cystoseira populations along the west Istrian Coast (Croatia) related to eutrophication patterns in the northern Adriatic Sea.

    PubMed

    Iveša, Ljiljana; Djakovac, Tamara; Devescovi, Massimo

    2016-05-15

    An exploration of historical data suggested that eutrophication patterns might drive long-term fluctuations in Cystoseira populations along the west Istrian Coast (northern Adriatic Sea, Croatia). The regimes of northern Italian rivers, which flow approximately 100km west of the study area, mainly modulate the eutrophication levels of the northern Adriatic Sea. A regression of Cystoseira populations from the 1970s through the 1990s corresponded to increased levels of eutrophication in the study area. During the late 1990s, the density of sea urchins, which are efficacious macroalgal predators, decreased, likely due to an intense formation of pelagic mucilage aggregates that resulted in mass mortality episodes of macrozoobenthic species. During the 2000-2013 period, an oligotrophication of the northern Adriatic formed the basis for the recovery of Cystoseira taxa, whose abundances from 2009 to 2013 were similar to those characterising the most flourishing Mediterranean Cystoseira assemblages.

  18. The roles of flowering, overwinter survival and sea surface temperature in the long-term population dynamics of Zostera marina around the Isles of Scilly, UK.

    PubMed

    Potouroglou, Maria; Kenyon, Emma J; Gall, Angie; Cook, Kevan J; Bull, James C

    2014-06-30

    Interaction between biotic and abiotic drivers of dynamics is an important topic in ecology. Despite numerous short-term studies, there is a paucity of evidence about how environmental structure modifies dynamics in marine systems. We quantified Zostera marina flowering and non-flowering shoot density annually from 1996 to 2012 around the Isles of Scilly, UK, parameterizing a population dynamic model. Flowering is structured in time and space, with temperature and flowering positively associated at some locations only. We found no evidence that flower production contributes to seagrass density but 'patchiness' was positively associated with flowering in the previous year. With evidence of substantial overwinter survival, findings support the hypothesis that local populations are maintained largely through vegetative reproduction but sexual reproduction may contribute to colonisation of vacant habitat. This long-term study (1) tests validity of shorter-term investigations, (2) quantifies interaction between biotic and abiotic factors and (3) promotes seagrass as a model ecosystem. PMID:24731880

  19. The roles of flowering, overwinter survival and sea surface temperature in the long-term population dynamics of Zostera marina around the Isles of Scilly, UK.

    PubMed

    Potouroglou, Maria; Kenyon, Emma J; Gall, Angie; Cook, Kevan J; Bull, James C

    2014-06-30

    Interaction between biotic and abiotic drivers of dynamics is an important topic in ecology. Despite numerous short-term studies, there is a paucity of evidence about how environmental structure modifies dynamics in marine systems. We quantified Zostera marina flowering and non-flowering shoot density annually from 1996 to 2012 around the Isles of Scilly, UK, parameterizing a population dynamic model. Flowering is structured in time and space, with temperature and flowering positively associated at some locations only. We found no evidence that flower production contributes to seagrass density but 'patchiness' was positively associated with flowering in the previous year. With evidence of substantial overwinter survival, findings support the hypothesis that local populations are maintained largely through vegetative reproduction but sexual reproduction may contribute to colonisation of vacant habitat. This long-term study (1) tests validity of shorter-term investigations, (2) quantifies interaction between biotic and abiotic factors and (3) promotes seagrass as a model ecosystem.

  20. Some results of long-term investigation population exposed as a result of release of radioactive wastes into the Techa River in Southern Urals

    SciTech Connect

    Degteva, M.O.; Kozheurov, V.P.; Vorobiova, M.I.

    1992-06-01

    This paper describes results of a long-term investigation of a population exposed to radioactive waste release in 1949-1956 into the Techa River in the Southern Urals. Systematic measurements of radionuclide concentration in the river waters, sediments, and floodplain soils and measurements of exposure gamma dose rates as well as studies of the radionuclide composition in the contaminated areas began in the summer of 1951. As a result of the contamination, 124,000 residents were exposed to radiation and 28,100 received significant doses in terms of health effect potential. Covered results include the following: estimation of external radiation doses; content of strontium-90 in humans and estimation of radionuclide ingestion rates; age-dependent model of strontium metabolism in the human body; evaluation of doses of internal irradiation; distribution of exposed population according to accumulated doses. 11 refs; 15 figs.

  1. Long-term fluctuations in Cystoseira populations along the west Istrian Coast (Croatia) related to eutrophication patterns in the northern Adriatic Sea.

    PubMed

    Iveša, Ljiljana; Djakovac, Tamara; Devescovi, Massimo

    2016-05-15

    An exploration of historical data suggested that eutrophication patterns might drive long-term fluctuations in Cystoseira populations along the west Istrian Coast (northern Adriatic Sea, Croatia). The regimes of northern Italian rivers, which flow approximately 100km west of the study area, mainly modulate the eutrophication levels of the northern Adriatic Sea. A regression of Cystoseira populations from the 1970s through the 1990s corresponded to increased levels of eutrophication in the study area. During the late 1990s, the density of sea urchins, which are efficacious macroalgal predators, decreased, likely due to an intense formation of pelagic mucilage aggregates that resulted in mass mortality episodes of macrozoobenthic species. During the 2000-2013 period, an oligotrophication of the northern Adriatic formed the basis for the recovery of Cystoseira taxa, whose abundances from 2009 to 2013 were similar to those characterising the most flourishing Mediterranean Cystoseira assemblages. PMID:26975612

  2. Long-term development of the radionuclide exposure of murine rodent populations in Belarus after the Chernobyl accident.

    PubMed

    Ryabokon, N I; Smolich, I I; Kudryashov, V P; Goncharova, R I

    2005-12-01

    As a determinant of the associated health risks, the behavior of radionuclides in natural ecosystems needs to be better understood. Therefore, the activity concentration of various long-lived radionuclides released due to the Chernobyl accident, and the corresponding contributions to the whole-body dose rate, was studied as a function of time in mammalian indicator species inhabiting the natural forest ecosystems of Belarus, the bank vole (Clethrionomys glareolus) and the yellow-necked mouse (Apodemus flavicollus). The activity concentrations of 137Cs, 134Cs, 90Sr, 238Pu, 239,240Pu, 241Pu and 241Am in soil and in animals were measured at five monitoring sites with different ground deposition of radionuclides at different distances from the destroyed reactor. The observed temporal pattern of the radionuclide activity concentration in the studied animal populations reflects the changes in biological availability of these isotopes for biota, mostly due to fuel particle destruction and appearance of dissolved and exchangeable forms of radionuclides. The time course of 134+137Cs activity concentrations in animal populations appeared as a sequence of increase, peak and decrease. Maximal levels of radiocesium occurred 1-2 years after deposition, followed by an exponential decrease. Concentrations of incorporated 90Sr increased up to the tenth year after deposition. The activity concentrations of transuranic elements (238Pu, 239,240Pu, 241Pu and 241Am) were much lower than those of the other radionuclides, in the studied animals. A considerable activity of 241Am in animals from areas with high levels of contamination was firstly detected 5 years after deposition, it increased up to the tenth year and is expected to increase further in the future. Maximal values of the whole-body absorbed dose rates occurred during the year of deposition, followed by a decrease in the subsequent period. Generally, this decrease was monotonic, mainly determined by the decrease of the

  3. Long-term development of the radionuclide exposure of murine rodent populations in Belarus after the Chernobyl accident.

    PubMed

    Ryabokon, N I; Smolich, I I; Kudryashov, V P; Goncharova, R I

    2005-12-01

    As a determinant of the associated health risks, the behavior of radionuclides in natural ecosystems needs to be better understood. Therefore, the activity concentration of various long-lived radionuclides released due to the Chernobyl accident, and the corresponding contributions to the whole-body dose rate, was studied as a function of time in mammalian indicator species inhabiting the natural forest ecosystems of Belarus, the bank vole (Clethrionomys glareolus) and the yellow-necked mouse (Apodemus flavicollus). The activity concentrations of 137Cs, 134Cs, 90Sr, 238Pu, 239,240Pu, 241Pu and 241Am in soil and in animals were measured at five monitoring sites with different ground deposition of radionuclides at different distances from the destroyed reactor. The observed temporal pattern of the radionuclide activity concentration in the studied animal populations reflects the changes in biological availability of these isotopes for biota, mostly due to fuel particle destruction and appearance of dissolved and exchangeable forms of radionuclides. The time course of 134+137Cs activity concentrations in animal populations appeared as a sequence of increase, peak and decrease. Maximal levels of radiocesium occurred 1-2 years after deposition, followed by an exponential decrease. Concentrations of incorporated 90Sr increased up to the tenth year after deposition. The activity concentrations of transuranic elements (238Pu, 239,240Pu, 241Pu and 241Am) were much lower than those of the other radionuclides, in the studied animals. A considerable activity of 241Am in animals from areas with high levels of contamination was firstly detected 5 years after deposition, it increased up to the tenth year and is expected to increase further in the future. Maximal values of the whole-body absorbed dose rates occurred during the year of deposition, followed by a decrease in the subsequent period. Generally, this decrease was monotonic, mainly determined by the decrease of the

  4. Response of microbial community of tundra soil to global warming: Simulation of seasonal and long-term population dynamics

    SciTech Connect

    Panikov, N.S.

    1994-11-01

    A mathematical model has been constructed and verified to simulate dynamics of a microbial community in typical tundra. The model contains the following state variables: the population densities of three competing microbial species (exemplified by Arthrobacter, Pseudomonas, and Bacillus), indexes of their physiological state, concentration of available organic substrate, plant litter reserves, the amount of microbiovorous protozoans, and temperature. The mathematical model simulates adequately the qualitative features of microbial seasonal dynamics observed in tundra. The global warming and associated increase in primary productivity, as predicted by simulation, will relieve the pressure of L-selection and thus result in stabilization of the tundra microbial community. The model also predicts that aerobic decomposition of dead organic matter in solid will be accelerated compared to its formation. 24 refs., 7 figs., 1 tab.

  5. Correlations between postural stability and strength of lower body extremities of women population living in long-term care facilities.

    PubMed

    Wiacek, Magdalena; Hagner, Wojciech; Hagner-Derengowska, Magdalena; Bluj, Barbara; Drozd, Monika; Czereba, Jolanta; Zubrzycki, Igor Z

    2009-01-01

    The present study was aimed at analyzing correlation between strength of lower body extremities and postural stability in function of age. A pool of 180 women divided into 6 age groups (65-69, 70-74, 75-79, 80-84, 85-89 and 90-94 years) was examined. They all were informed-consent participants. The results suggest that age is negatively correlated with lower body strength and positively correlated with decrease of postural balance. There is also an exponential correlation between the strength of lower body part and postural balance. The conclusion was derived that postural stability is at least partially controlled by the strength of lower body. The age of 75 in women population seems to be a threshold above which the neurodegenerative and muscle degeneration processes are responsible for significant increase of risk of fall.

  6. Phylogeography, genetic structure and population divergence time of cheetahs in Africa and Asia: evidence for long-term geographic isolates

    PubMed Central

    Charruau, P; Fernandes, C; Orozco-terWengel, P; Peters, J; Hunter, L; Ziaie, H; Jourabchian, A; Jowkar, H; Schaller, G; Ostrowski, S; Vercammen, P; Grange, T; Schlötterer, C; Kotze, A; Geigl, E-M; Walzer, C; Burger, P A

    2011-01-01

    The cheetah (Acinonyx jubatus) has been described as a species with low levels of genetic variation. This has been suggested to be the consequence of a demographic bottleneck 10 000–12 000 years ago (ya) and also led to the assumption that only small genetic differences exist between the described subspecies. However, analysing mitochondrial DNA and microsatellites in cheetah samples from most of the historic range of the species we found relatively deep phylogeographic breaks between some of the investigated populations, and most of the methods assessed divergence time estimates predating the postulated bottleneck. Mitochondrial DNA monophyly and overall levels of genetic differentiation support the distinctiveness of Northern-East African cheetahs (Acinonyx jubatus soemmeringii). Moreover, combining archaeozoological and contemporary samples, we show that Asiatic cheetahs (Acinonyx jubatus venaticus) are unambiguously separated from African subspecies. Divergence time estimates from mitochondrial and nuclear data place the split between Asiatic and Southern African cheetahs (Acinonyx jubatus jubatus) at 32 000–67 000 ya using an average mammalian microsatellite mutation rate and at 4700–44 000 ya employing human microsatellite mutation rates. Cheetahs are vulnerable to extinction globally and critically endangered in their Asiatic range, where the last 70–110 individuals survive only in Iran. We demonstrate that these extant Iranian cheetahs are an autochthonous monophyletic population and the last representatives of the Asiatic subspecies A. j. venaticus. We advocate that conservation strategies should consider the uncovered independent evolutionary histories of Asiatic and African cheetahs, as well as among some African subspecies. This would facilitate the dual conservation priorities of maintaining locally adapted ecotypes and genetic diversity. PMID:21214655

  7. The Phenology of Ticks and the Effects of Long-Term Prescribed Burning on Tick Population Dynamics in Southwestern Georgia and Northwestern Florida

    PubMed Central

    Gleim, Elizabeth R.; Conner, L. Mike; Berghaus, Roy D.; Levin, Michael L.; Zemtsova, Galina E.; Yabsley, Michael J.

    2014-01-01

    Some tick populations have increased dramatically in the past several decades leading to an increase in the incidence and emergence of tick-borne diseases. Management strategies that can effectively reduce tick populations while better understanding regional tick phenology is needed. One promising management strategy is prescribed burning. However, the efficacy of prescribed burning as a mechanism for tick control is unclear because past studies have provided conflicting data, likely due to a failure of some studies to simulate operational management scenarios and/or account for other predictors of tick abundance. Therefore, our study was conducted to increase knowledge of tick population dynamics relative to long-term prescribed fire management. Furthermore, we targeted a region, southwestern Georgia and northwestern Florida (USA), in which little is known regarding tick dynamics so that basic phenology could be determined. Twenty-one plots with varying burn regimes (burned surrounded by burned [BB], burned surrounded by unburned [BUB], unburned surrounded by burned [UBB], and unburned surrounded by unburned [UBUB]) were sampled monthly for two years while simultaneously collecting data on variables that can affect tick abundance (e.g., host abundance, vegetation structure, and micro- and macro-climatic conditions). In total, 47,185 ticks were collected, of which, 99% were Amblyomma americanum, 0.7% were Ixodes scapularis, and fewer numbers of Amblyomma maculatum, Ixodes brunneus, and Dermacentor variabilis. Monthly seasonality trends were similar between 2010 and 2011. Long-term prescribed burning consistently and significantly reduced tick counts (overall and specifically for A. americanum and I. scapularis) regardless of the burn regimes and variables evaluated. Tick species composition varied according to burn regime with A. americanum dominating at UBUB, A. maculatum at BB, I. scapularis at UBB, and a more even composition at BUB. These data indicate that

  8. Trace metals in the environment and population as possible long term consequence of war in Osijek-Baranja County, Croatia.

    PubMed

    Vidosavljević, Domagoj; Puntarić, Dinko; Gvozdić, Vlatka; Jergović, Matijana; Jurčev-Savičević, Anamarija; Puntarić, Ida; Vidosavljević, Marina

    2014-09-01

    War in Croatia resulted with a significant release of contaminants into the environment as a result of the use of combat assets, mainly conventional, mostly aimed at civilian targets. The aim of the study was to investigate the concentration of metals and metalloids in the soils, water, plants (Taraxacum officinale), serum, urine and hair of the inhabitants in eastern Croatia. Overall results show minor abnormalities in presence of some trace metals in soil (As, Hg, Pb, Sb), water (As, Fe) and dandelion leaves (As) in some locations. Compared with soil samples from areas exposed to low intensity combat activity soil samples from areas exposed to heavy fighting had higher concentrations of As, Hg and Pb than allowed by national legislation for ecologic farming. Drinking water with the exceptions of the concentrations of Fe, As and Mn was in accordance with national legislation. Examinees from Dalj had mean hair Sb level 10-19x higher then examinees from any other location. However, when these data are correlated through methods of principal component analysis, presence of trace metals in some war affected areas can be followed from soil, through plants up to population proving that intense combat activities over small area leave metal presence that can be followed even 15 years after the war. PMID:25507359

  9. Trace metals in the environment and population as possible long term consequence of war in Osijek-Baranja County, Croatia.

    PubMed

    Vidosavljević, Domagoj; Puntarić, Dinko; Gvozdić, Vlatka; Jergović, Matijana; Jurčev-Savičević, Anamarija; Puntarić, Ida; Vidosavljević, Marina

    2014-09-01

    War in Croatia resulted with a significant release of contaminants into the environment as a result of the use of combat assets, mainly conventional, mostly aimed at civilian targets. The aim of the study was to investigate the concentration of metals and metalloids in the soils, water, plants (Taraxacum officinale), serum, urine and hair of the inhabitants in eastern Croatia. Overall results show minor abnormalities in presence of some trace metals in soil (As, Hg, Pb, Sb), water (As, Fe) and dandelion leaves (As) in some locations. Compared with soil samples from areas exposed to low intensity combat activity soil samples from areas exposed to heavy fighting had higher concentrations of As, Hg and Pb than allowed by national legislation for ecologic farming. Drinking water with the exceptions of the concentrations of Fe, As and Mn was in accordance with national legislation. Examinees from Dalj had mean hair Sb level 10-19x higher then examinees from any other location. However, when these data are correlated through methods of principal component analysis, presence of trace metals in some war affected areas can be followed from soil, through plants up to population proving that intense combat activities over small area leave metal presence that can be followed even 15 years after the war. PMID:25420375

  10. Effects of Orbital Lifetime Reduction on the Long-Term Earth Satellite Population as Modeled by EVOLVE 4.0

    NASA Technical Reports Server (NTRS)

    Krisko, Paula H.; Opiela, John N.; Liou, Jer-Chyi; Anz-Meador, Phillip D.; Theall, Jeffrey R.

    1999-01-01

    The latest update of the NASA orbital debris environment model, EVOLVE 4.0, has been used to study the effect of various proposed debris mitigation measures, including the NASA 25-year guideline. EVOLVE 4.0, which includes updates of the NASA breakup, solar activity, and the orbit propagator models, a GEO analysis option, and non-fragmentation debris source models, allows for the statistical modeling and predicted growth of the particle population >1 mm in characteristic length in LEO and GEO orbits. The initial implementation of this &odel has been to study the sensitivity of the overall LEO debris environment to mitigation measures designed to limit the lifetime of intact objects in LEO orbits. The mitigation measures test matrix for this study included several commonly accepted testing schemes, i.e., the variance of the maximum LEO lifetime from 10 to 50 years, the date of the initial implementation of this policy, the shut off of all explosions at some specified date, and the inclusion of disposal orbits. All are timely studies in that all scenarios have been suggested by researchers and satellite operators as options for the removal of debris from LEO orbits.

  11. Long-term fracture risk in patients with celiac disease: a population-based study in Olmsted County, Minnesota.

    PubMed

    Jafri, Mohammed R; Nordstrom, Charles W; Murray, Joseph A; Van Dyke, Carol T; Dierkhising, Ross A; Zinsmeister, Alan R; Melton, Lee J

    2008-04-01

    Celiac disease is associated with decreased bone density, but there are conflicting data regarding fracture risk. We determined the fracture incidence relative to matched controls in a population-based cohort with celiac disease before and after diagnosis. Olmsted County residents with celiac disease (n = 83) diagnosed between 1950 and 2002 were compared with 166 gender and age matched controls. Fracture histories were ascertained from each subject's medical records. Celiac disease is linked to an increased fracture risk before and after diagnosis. Before the index date, cases had a fracture rate twice that of controls (CI: 1.0-3.9, P = 0.045) and 2.5-fold greater after the index date (CI: 1.1-5.6, P = 0.026). Appendicular and axial fractures were 2.5 (CI: 0.9-6.5) and 3.2 times more likely (CI: 1.0-10.5) after the index date. These observations support a rationale for earlier detection of celiac disease, and active management of bone disease before bone effects have occurred, to reduce the persistent risk of fractures.

  12. Long-term fracture risk in patients with celiac disease: a population-based study in Olmsted County, Minnesota.

    PubMed

    Jafri, Mohammed R; Nordstrom, Charles W; Murray, Joseph A; Van Dyke, Carol T; Dierkhising, Ross A; Zinsmeister, Alan R; Melton, Lee J

    2008-04-01

    Celiac disease is associated with decreased bone density, but there are conflicting data regarding fracture risk. We determined the fracture incidence relative to matched controls in a population-based cohort with celiac disease before and after diagnosis. Olmsted County residents with celiac disease (n = 83) diagnosed between 1950 and 2002 were compared with 166 gender and age matched controls. Fracture histories were ascertained from each subject's medical records. Celiac disease is linked to an increased fracture risk before and after diagnosis. Before the index date, cases had a fracture rate twice that of controls (CI: 1.0-3.9, P = 0.045) and 2.5-fold greater after the index date (CI: 1.1-5.6, P = 0.026). Appendicular and axial fractures were 2.5 (CI: 0.9-6.5) and 3.2 times more likely (CI: 1.0-10.5) after the index date. These observations support a rationale for earlier detection of celiac disease, and active management of bone disease before bone effects have occurred, to reduce the persistent risk of fractures. PMID:17934823

  13. Predicting long-term cardiovascular risk using the mayo clinic cardiovascular risk score in a referral population.

    PubMed

    Dhoble, Abhijeet; Lahr, Brian D; Allison, Thomas G; Bailey, Kent R; Thomas, Randal J; Lopez-Jimenez, Francisco; Kullo, Iftikhar J; Gupta, Bhanu; Kopecky, Stephen L

    2014-09-01

    Exercise testing provides valuable information but is rarely integrated to derive a risk prediction model in a referral population. In this study, we assessed the predictive value of conventional cardiovascular risk factors and exercise test parameters in 6,546 consecutive adults referred for exercise testing, who were followed for a period of 8.1 ± 3.7 years for incident myocardial infarction, coronary revascularization, and cardiovascular death. A risk prediction model was developed, and cross-validation of model was performed by splitting the data set into 10 equal random subsets, with model fitting based on 9 of the 10 subsets and testing in of the remaining subset, repeated in all 10 possible ways. The best performing model was chosen based on measurements of model discrimination and stability. A risk score was constructed from the final model, with points assigned for the presence of each predictor based on the regression coefficients. Using both conventional risk factors and exercise test parameters, a total of 9 variables were identified as independent and robust predictors and were included in a risk score. The prognostic ability of this model was compared with that of the Adult Treatment Panel III model using the net reclassification and integrated discrimination index. From the cross-validation results, the c statistic of 0.77 for the final model indicated strong predictive power. In conclusion, we developed, tested, and internally validated a novel risk prediction model using exercise treadmill testing parameters. PMID:25052544

  14. Walleye consumption and long-term population trends following gizzard shad introduction into a Western South Dakota reservoir

    USGS Publications Warehouse

    Ward, M.J.; Willis, D.W.; Miller, B.H.; Chipps, S.R.

    2007-01-01

    The gizzard shad (Dorosoma cepedianum) was introduced into 1,955-ha Angostura Reservoir, South Dakota to provide increased prey resources for walleye (Sander vitreus). Linear correlation analysis indicated that following gizzard shad introduction, walleye catch-per-unit-effort and mean length at age have increased over time (r = 0.68 to 0.85, P = 0.02 to 0.001). Walleye stomach contents were collected monthly from April through September, 2004 to determine the extent to which age-0 gizzard shad were being utilized as prey during the growing season. Age-0 gizzard shad were absent from walleye diets from April to mid-July (pre-shad-available period); however, from mid-July through early September (shad-available period), age-0 gizzard shad were an important prey item in all walleye diets. Mean weight decreased for walleyes of ages 2-5 during the spring, before age-0 gizzard shad became available; however, growth rate of walleyes increased appreciably during the shad-available period and was attributable to consumption of age-0 shad prey. In Angostura Reservoir, which lies at the northwestern edge of the gizzard shad range, walleye population characteristics have improved following shad introduction and during 2004, age-0 shad directly affected walleye feeding and growth.

  15. [Effects of long-term petroleum and heavy metals pollution on the diversity and community structure of Pesudomonas populations in agricultural soils].

    PubMed

    Zhang, Qin; Zhang, Hui-wen; Su, Zhen-cheng; Li, Xin-yu; Zhang, Cheng-gang

    2007-06-01

    By using PCR-DGGE method, this paper studied the diversity and community structure of Pseudomonas populations in long-term petroleum- and heavy metals-contaminated agricultural soils in Northeast China. The results showed that the Shannon diversity index of Pseudomonas was significantly higher in petroleum- than in heavy metals-contaminated soils. The diversity of Pseudomonas in petroleum-contaminated soil was approached to that in clean soil but lower than that in polluted lowland rice soil, suggesting that contaminant type and cultivation mode were the main factors affecting the diversity of Pseudomonas in agricultural soils. The sequences of V6/V7 regions in 16S rRNA gene indicated that P. mendocina, P. stutzeri and P. aeruginosa were the dominant species in both petroleum- and heavy metals-contaminated soils, demonstrating that these three species were enriched under the stress of long-term pollution, which might correlate with the natural degradation of petroleum and the resistance of Pseudomonas to heavy metals. PMID:17763738

  16. Long-term effects of wildfire on greater sage-grouse - integrating population and ecosystem concepts for management in the Great Basin

    USGS Publications Warehouse

    Coates, Peter S.; Ricca, Mark A.; Prochazka, Brian G.; Doherty, Kevin E.; Brooks, Matthew L.; Casazza, Michael L.

    2015-09-10

    Greater sage-grouse (Centrocercus urophasianus; hereinafter, sage-grouse) are a sagebrush obligate species that has declined concomitantly with the loss and fragmentation of sagebrush ecosystems across most of its geographical range. The species currently is listed as a candidate for federal protection under the Endangered Species Act (ESA). Increasing wildfire frequency and changing climate frequently are identified as two environmental drivers that contribute to the decline of sage-grouse populations, yet few studies have rigorously quantified their effects on sage-grouse populations across broad spatial scales and long time periods. To help inform a threat assessment within the Great Basin for listing sage-grouse in 2015 under the ESA, we conducted an extensive analysis of wildfire and climatic effects on sage-grouse population growth derived from 30 years of lek-count data collected across the hydrographic Great Basin of Western North America. Annual (1984–2013) patterns of wildfire were derived from an extensive dataset of remotely sensed 30-meter imagery and precipitation derived from locally downscaled spatially explicit data. In the sagebrush ecosystem, underlying soil conditions also contribute strongly to variation in resilience to disturbance and resistance to plant community changes (R&R). Thus, we developed predictions from models of post-wildfire recovery and chronic effects of wildfire based on three spatially explicit R&R classes derived from soil moisture and temperature regimes. We found evidence of an interaction between the effects of wildfire (chronically affected burned area within 5 kilometers of a lek) and climatic conditions (spring through fall precipitation) after accounting for a consistent density-dependent effect. Specifically, burned areas near leks nullifies population growth that normally follows years with relatively high precipitation. In models, this effect results in long-term population declines for sage-grouse despite cyclic

  17. Population-level Consequences of Breeding Phenology in Response to Climate Variability in Seabirds and Landbirds: Two Long-term Studies From California

    NASA Astrophysics Data System (ADS)

    Warzybok, P.; Nur, N.; Bradley, R.; Sydeman, W. J.; Abraham, C.; Chase, M. K.

    2007-12-01

    Long-term studies conducted on breeding populations on the Farallon Islands (1971 to 2007) and in the Point Reyes National Seashore (1980 to 2007), provide the means to characterize breeding phenology of seabird and landbird species and determine how that has changed over multiple temporal scales (variation among years, among decades, shifts in ocean regimes, etc.). However, to interpret phenological patterns and shifts requires information on the demography and ecological context of these species. Here we describe studies on three seabird species (Common Murre Uria aalge, Cassin's Auklet Ptychoramphus aleuticus, Brandt's Cormorant, Phalacrocorax penicillatus) where we have tied changes in breeding phenology, within a year, and among years, to demographic consequences (reproductive success, proportion of the population that breeds, adult survival, etc.). In addition, for these species we have information on diet choice of parents feeding chicks and how that has varied within and among years, as well as oceanographic correlates (sea surface temperature, upwelling indices, etc). Results reveal marked variation among the species in their response to oceanographic and climate variability, reflecting their different ecologies. We describe how these results can be used to forecast response to future climate change, as well as to interpret year by response to climate variability. We also summarize results from a long-term study of Song Sparrows (Melospiza melodia), where we have investigated onset and termination of breeding and the climate factors that may influence it, while identifying the population-level responses associated with phenological shifts. We close by making recommendations for large-scale monitoring of phenology based on these more localized studies.

  18. Population signatures of large-scale, long-term disjunction and small-scale, short-term habitat fragmentation in an Afromontane forest bird.

    PubMed

    Habel, J C; Mulwa, R K; Gassert, F; Rödder, D; Ulrich, W; Borghesio, L; Husemann, M; Lens, L

    2014-09-01

    The Eastern Afromontane cloud forests occur as geographically distinct mountain exclaves. The conditions of these forests range from large to small and from fairly intact to strongly degraded. For this study, we sampled individuals of the forest bird species, the Montane White-eye Zosterops poliogaster from 16 sites and four mountain archipelagos. We analysed 12 polymorphic microsatellites and three phenotypic traits, and calculated Species Distribution Models (SDMs) to project past distributions and predict potential future range shifts under a scenario of climate warming. We found well-supported genetic and morphologic clusters corresponding to the mountain ranges where populations were sampled, with 43% of all alleles being restricted to single mountains. Our data suggest that large-scale and long-term geographic isolation on mountain islands caused genetically and morphologically distinct population clusters in Z. poliogaster. However, major genetic and biometric splits were not correlated to the geographic distances among populations. This heterogeneous pattern can be explained by past climatic shifts, as highlighted by our SDM projections. Anthropogenically fragmented populations showed lower genetic diversity and a lower mean body mass, possibly in response to suboptimal habitat conditions. On the basis of these findings and the results from our SDM analysis we predict further loss of genotypic and phenotypic uniqueness in the wake of climate change, due to the contraction of the species' climatic niche and subsequent decline in population size.

  19. Population signatures of large-scale, long-term disjunction and small-scale, short-term habitat fragmentation in an Afromontane forest bird

    PubMed Central

    Habel, J C; Mulwa, R K; Gassert, F; Rödder, D; Ulrich, W; Borghesio, L; Husemann, M; Lens, L

    2014-01-01

    The Eastern Afromontane cloud forests occur as geographically distinct mountain exclaves. The conditions of these forests range from large to small and from fairly intact to strongly degraded. For this study, we sampled individuals of the forest bird species, the Montane White-eye Zosterops poliogaster from 16 sites and four mountain archipelagos. We analysed 12 polymorphic microsatellites and three phenotypic traits, and calculated Species Distribution Models (SDMs) to project past distributions and predict potential future range shifts under a scenario of climate warming. We found well-supported genetic and morphologic clusters corresponding to the mountain ranges where populations were sampled, with 43% of all alleles being restricted to single mountains. Our data suggest that large-scale and long-term geographic isolation on mountain islands caused genetically and morphologically distinct population clusters in Z. poliogaster. However, major genetic and biometric splits were not correlated to the geographic distances among populations. This heterogeneous pattern can be explained by past climatic shifts, as highlighted by our SDM projections. Anthropogenically fragmented populations showed lower genetic diversity and a lower mean body mass, possibly in response to suboptimal habitat conditions. On the basis of these findings and the results from our SDM analysis we predict further loss of genotypic and phenotypic uniqueness in the wake of climate change, due to the contraction of the species' climatic niche and subsequent decline in population size. PMID:24713824

  20. Moving house: long-term dynamics of corticosterone secretion are unaltered in translocated populations of a rare reptile (the tuatara, Sphenodon punctatus)

    PubMed Central

    Anderson, Lindsay E.; Cree, Alison; Towns, David R.; Nelson, Nicola J.

    2015-01-01

    Translocations are an important conservation tool used to restore at-risk species to their historical range. Unavoidable procedures during translocations, such as habitat disturbance, capture, handling, processing, captivity, transport and release to a novel environment, have the potential to be stressful for most species. In this study, we examined acute and chronic stress (through the measurement of the glucocorticoid corticosterone) in a rare reptile (the tuatara, Sphenodon punctatus). We found that: (i) the acute corticosterone response remains elevated during the initial translocation process but is not amplified by cumulative stressors; and (ii) the long-term dynamics of corticosterone secretion are similar in translocated and source populations. Taken together, our results show that translocated tuatara are generally resistant to cumulative acute stressors and show no hormonal sign of chronic stress. Translocation efforts in tuatara afford the potential to reduce extinction risk and restore natural ecosystems. PMID:27293699

  1. Risk of death from cardiovascular disease associated with low-level arsenic exposure among long-term smokers in a US population-based study

    SciTech Connect

    Farzan, Shohreh F.; Chen, Yu; Rees, Judy R.; Zens, M. Scot; Karagas, Margaret R.

    2015-09-01

    High levels of arsenic exposure have been associated with increases in cardiovascular disease risk. However, studies of arsenic's effects at lower exposure levels are limited and few prospective studies exist in the United States using long-term arsenic exposure biomarkers. We conducted a prospective analysis of the association between toenail arsenic and cardiovascular disease mortality using longitudinal data collected on 3939 participants in the New Hampshire Skin Cancer Study. Using Cox proportional hazard models adjusted for potential confounders, we estimated hazard ratios and 95% confidence intervals associated with the risk of death from any cardiovascular disease, ischemic heart disease, and stroke, in relation to natural-log transformed toenail arsenic concentrations. In this US population, although we observed no overall association, arsenic exposure measured from toenail clipping samples was related to an increased risk of ischemic heart disease mortality among long-term smokers (as reported at baseline), with increased hazard ratios among individuals with ≥ 31 total smoking years (HR: 1.52, 95% CI: 1.02, 2.27), ≥ 30 pack-years (HR: 1.66, 95% CI: 1.12, 2.45), and among current smokers (HR: 1.69, 95% CI: 1.04, 2.75). These results are consistent with evidence from more highly exposed populations suggesting a synergistic relationship between arsenic exposure and smoking on health outcomes and support a role for lower-level arsenic exposure in ischemic heart disease mortality. - Highlights: • Arsenic (As) has been associated with increased cardiovascular disease (CVD) risk. • Little is known about CVD effects at lower levels of As exposure common in the US. • Few have investigated the joint effects of As and smoking on CVD in US adults. • We examine chronic low-level As exposure and smoking in relation to CVD mortality. • Arsenic exposure may increase ischemic heart disease mortality among smokers in US.

  2. A disintegrin and metalloprotease 33 polymorphism association with COPD in long-term tobacco smokers of the ethnic Kashmiri population of India

    PubMed Central

    Shah, Sonaullah; Rashid, Amir; Shah, Zaffar A; Jan, Rafi Ahmad; Khan, Umar Hafiz; Bhat, Imtiyaz A; Mantoo, Suhail; Shah, Tajamul H; Koul, Parvaiz A

    2015-01-01

    Background: Chronic obstructive pulmonary disease (COPD) is characterized by an interaction of various environmental influences especially cigarette smoking and genetic determinants. The prevalence of this disease is ever increasing and characterization of the genetic determinants of the disease has been undertaken globally. The ‘A disintegrin and metalloprotease 33’ (ADAM 33) gene is one candidate gene that has been studied. Objective: Our objective was to investigate whether single nucleotide polymorphisms in ADAM33 gene are associated with COPD in long-term tobacco smokers in the ethnic Kashmiri population of northern India. Materials and Methods: This was a randomized case-control study, which included 78 stable COPD (GOLD stage11-IV) patients, who were compared with 77 age- and sex-matched long-term tobacco smokers (>20 pack years) without any evidence of COPD. Polymorphic analysis for three single nucleotide polymorphisms (SNPs), (T1, T2, and Q1) of the ADAM33 gene was done by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) followed by sequencing. The data were analyzed by descriptive statistics and comparative evaluation was done by parametric/non-parametric tests. Results: The analysis of the T1, T2, and Q1 SNPs, revealed that the frequencies of the T2GG, T1GG, and the Q1AG genotypes were significantly higher in patients with COPD in comparison with the controls (P < 0.001). Similarly, the T1G and T2G allele frequency was higher in the patients than in the controls (p = 0.177 and 0.43, respectively). Conclusion: Three SNPs of the ADAM33 gene were significantly associated with COPD in the Kashmiri population of India. This study establishes the possible role of ADAM33 SNPS in the causation of COPD. Further studies across different geographical areas in the country will unravel the contribution of this gene in the causation of COPD in India. PMID:25983406

  3. Causes of Morbidity in Wild Raptor Populations Admitted at a Wildlife Rehabilitation Centre in Spain from 1995-2007: A Long Term Retrospective Study

    PubMed Central

    Molina-López, Rafael A.; Casal, Jordi; Darwich, Laila

    2011-01-01

    Background Morbidity studies complement the understanding of hazards to raptors by identifying natural or anthropogenic factors. Descriptive epidemiological studies of wildlife have become an important source of information about hazards to wildlife populations. On the other hand, data referenced to the overall wild population could provide a more accurate assessment of the potential impact of the morbidity/mortality causes in populations of wild birds. Methodology/Principal Findings The present study described the morbidity causes of hospitalized wild raptors and their incidence in the wild populations, through a long term retrospective study conducted at a wildlife rehabilitation centre of Catalonia (1995–2007). Importantly, Seasonal Cumulative Incidences (SCI) were calculated considering estimations of the wild population in the region and trend analyses were applied among the different years. A total of 7021 birds were analysed: 7 species of Strigiformes (n = 3521) and 23 of Falconiformes (n = 3500). The main causes of morbidity were trauma (49.5%), mostly in the Falconiformes, and orphaned/young birds (32.2%) mainly in the Strigiformes. During wintering periods, the largest morbidity incidence was observed in Accipiter gentillis due to gunshot wounds and in Tyto alba due to vehicle trauma. Within the breeding season, Falco tinnunculus (orphaned/young category) and Bubo bubo (electrocution and metabolic disorders) represented the most affected species. Cases due to orphaned/young, infectious/parasitic diseases, electrocution and unknown trauma tended to increase among years. By contrast, cases by undetermined cause, vehicle trauma and captivity decreased throughout the study period. Interestingly, gunshot injuries remained constant during the study period. Conclusions/Significance Frequencies of morbidity causes calculated as the proportion of each cause referred to the total number of admitted cases, allowed a qualitative assessment of hazards for

  4. Deep phylogeographic structuring of populations of the trapdoor spider Moggridgea tingle (Migidae) from southwestern Australia: evidence for long-term refugia within refugia.

    PubMed

    Cooper, Steven J B; Harvey, Mark S; Saint, Kathleen M; Main, Barbara Y

    2011-08-01

    Southwestern Australia has been recognized as a biodiversity hot spot of global significance, and it is particularly well known for its considerable diversity of flowering plant species. Questions of interest are how this region became so diverse and whether its fauna show similar diverse patterns of speciation. Here, we carried out a phylogeographic study of trapdoor spiders (Migidae: Moggridgea), a presumed Gondwanan lineage found in wet forest localities across southwestern Australia. Phylogenetic, molecular clock and population genetic analyses of mitochondrial (mtDNA) COI gene and ITS rRNA (internal transcribed spacer) data revealed considerable phylogeographic structuring of Moggridgea populations, with evidence for long-term (>3 million years) isolation of at least nine populations in different geographic locations, including upland regions of the Stirling and Porongurup Ranges. High levels of mtDNA divergence and no evidence of recent mitochondrial gene flow among valley populations of the Stirling Range suggest that individual valleys have acted as refugia for the spiders throughout the Pleistocene. Our findings support the hypothesis that climate change, particularly the aridification of Australia after the late Miocene, and the topography of the landscape, which allowed persistence of moist habitats, have been major drivers of speciation in southwestern Australia. PMID:21689192

  5. Deep phylogeographic structuring of populations of the trapdoor spider Moggridgea tingle (Migidae) from southwestern Australia: evidence for long-term refugia within refugia.

    PubMed

    Cooper, Steven J B; Harvey, Mark S; Saint, Kathleen M; Main, Barbara Y

    2011-08-01

    Southwestern Australia has been recognized as a biodiversity hot spot of global significance, and it is particularly well known for its considerable diversity of flowering plant species. Questions of interest are how this region became so diverse and whether its fauna show similar diverse patterns of speciation. Here, we carried out a phylogeographic study of trapdoor spiders (Migidae: Moggridgea), a presumed Gondwanan lineage found in wet forest localities across southwestern Australia. Phylogenetic, molecular clock and population genetic analyses of mitochondrial (mtDNA) COI gene and ITS rRNA (internal transcribed spacer) data revealed considerable phylogeographic structuring of Moggridgea populations, with evidence for long-term (>3 million years) isolation of at least nine populations in different geographic locations, including upland regions of the Stirling and Porongurup Ranges. High levels of mtDNA divergence and no evidence of recent mitochondrial gene flow among valley populations of the Stirling Range suggest that individual valleys have acted as refugia for the spiders throughout the Pleistocene. Our findings support the hypothesis that climate change, particularly the aridification of Australia after the late Miocene, and the topography of the landscape, which allowed persistence of moist habitats, have been major drivers of speciation in southwestern Australia.

  6. Health-related quality of life in chronic myeloid leukemia patients receiving long-term therapy with imatinib compared with the general population.

    PubMed

    Efficace, Fabio; Baccarani, Michele; Breccia, Massimo; Alimena, Giuliana; Rosti, Gianantonio; Cottone, Francesco; Deliliers, Giorgio Lambertenghi; Baratè, Claudia; Rossi, Antonella Russo; Fioritoni, Giuseppe; Luciano, Luigia; Turri, Diamante; Martino, Bruno; Di Raimondo, Francesco; Dabusti, Melissa; Bergamaschi, Micaela; Leoni, Pietro; Simula, Maria Pina; Levato, Luciano; Ulisciani, Stefano; Veneri, Dino; Sica, Simona; Rambaldi, Alessandro; Vignetti, Marco; Mandelli, Franco

    2011-10-27

    The main objective of this study was to investigate whether patients with chronic myeloid leukemia (CML) in treatment with long-term therapy imatinib have a different health-related quality-of-life (HRQOL) profile compared with the general population. In total, 448 CML patients were enrolled, and the SF-36 Health Survey was used to compare generic HRQOL profiles. Symptoms were also assessed. HRQOL comparisons were adjusted for key possible confounders. The median age of patients was 57 years and the median time of imatinib treatment was 5 years (range 3-9 years). The largest HRQOL differences were found in younger patients. In particular, patients aged between 18 and 39 years had marked impairments in role limitations because of physical and emotional problems, respectively: -22.6 (P < .001), -22.3 (P < .001). Patients with CML age 60 or older had a HRQOL profile very similar to that reported by the general population. Women had a worse profile than men when each were compared with their peers in the general population. Fatigue was the most frequently reported symptom. The HRQOL of CML patients is comparable with that of population norms in many areas, however, younger and female patients seem to report the major limitations.

  7. Community composition and population genetics of insect pathogenic fungi in the genus Metarhizium from soils of a long-term agricultural research system.

    PubMed

    Kepler, Ryan M; Ugine, Todd A; Maul, Jude E; Cavigelli, Michel A; Rehner, Stephen A

    2015-08-01

    Fungi in the genus Metarhizium are insect pathogens able to function in other niches, including soil and plant rhizosphere habitats. In agroecosystems, cropping and tillage practices influence soil fungal communities with unknown effects on the distribution of Metarhizium, whose presence can reduce populations of crop pests. We report results from a selective media survey of Metarhizium in soils sampled from a long-term experimental farming project in the mid-Atlantic region. Field plots under soybean cultivation produced higher numbers of Metarhizium colony-forming units (cfu) than corn or alfalfa. Plots managed organically and via chisel-till harboured higher numbers of Metarhizium cfu than no-till plots. Sequence typing of Metarhizium isolates revealed four species, with M. robertsii and M. brunneum predominating. The M. brunneum population was essentially fixed for a single clone as determined by multilocus microsatellite genotyping. In contrast, M. robertsii was found to contain significant diversity, with the majority of isolates distributed between two principal clades. Evidence for recombination was observed only in the most abundant clade. These findings illuminate multiple levels of Metarhizium diversity that can be used to inform strategies by which soil Metarhizium populations may be manipulated to exert downward pressure on pest insects and promote plant health. PMID:25627647

  8. Long-term Prognosis of Paroxysmal Atrial Fibrillation and Predictors for Progression to Persistnt or Chronic Atrial Fibrillation in the Korean Population.

    PubMed

    Im, Sung Ii; Chun, Kwang Jin; Park, Seung-Jung; Park, Kyoung-Min; Kim, June Soo; On, Young Keun

    2015-07-01

    Little is known about the long-term prognosis of or predictors for the different clinical types of atrial fibrillation (AF) in Korean populations. The aim of this study was to validate a risk stratification to assess the probability of AF progression from paroxysmal AF (PAF) to persistent AF (PeAF) or permanent AF. A total of 434 patients with PAF were consecutively enrolled (mean age; 71.7 ± 10.7 yr, 60.6% male). PeAF was defined as episodes that are sustained > 7 days and not self-terminating, while permanent AF was defined as an ongoing long-term episode. Atrial arrhythmia during follow-up was defined as atrial premature complex, atrial tachycardia, and atrial flutter. During a mean follow-up of 72.7 ± 58.3 months, 168 patients (38.7%) with PAF progressed to PeAF or permanent AF. The mean annual AF progression was 10.7% per year. In univariate analysis, age at diagnosis, body mass index, atrial arrhythmia during follow-up, left ventricular ejection fraction, concentric left ventricular hypertrophy, left atrial diameter (LAD), and severe mitral regurgitation (MR) were significantly associated with AF progression. In multivariate analysis, age at diagnosis (P = 0.009), atrial arrhythmia during follow-up (P = 0.015), LAD (P = 0.002) and MR grade (P = 0.026) were independent risk factors for AF progression. Patients with younger age at diagnosis, atrial arrhythmia during follow-up, larger left atrial chamber size, and severe MR grade are more likely to progress to PeAF or permanent AF, suggesting more intensive medical therapy with close clinical follow-up would be required in those patients.

  9. Prognosis for long-term survival and renal recovery in critically ill patients with severe acute renal failure: a population-based study

    PubMed Central

    Bagshaw, Sean M; Laupland, Kevin B; Doig, Christopher J; Mortis, Garth; Fick, Gordon H; Mucenski, Melissa; Godinez-Luna, Tomas; Svenson, Lawrence W; Rosenal, Tom

    2005-01-01

    Introduction Severe acute renal failure (sARF) is associated with considerable morbidity, mortality and use of healthcare resources; however, its precise epidemiology and long-term outcomes have not been well described in a non-specified population. Methods Population-based surveillance was conducted among all adult residents of the Calgary Health Region (population 1 million) admitted to multidisciplinary and cardiovascular surgical intensive care units between May 1 1999 and April 30 2002. Clinical records were reviewed and outcome at 1 year was assessed. Results sARF occurred in 240 patients (11.0 per 100,000 population/year). Rates were highest in males and older patients (≥65 years of age). Risk factors for development of sARF included previous heart disease, stroke, pulmonary disease, diabetes mellitus, cancer, connective tissue disease, chronic renal dysfunction, and alcoholism. The annual mortality rate was 7.3 per 100,000 population with rates highest in males and those ≥65 years. The 28-day, 90-day, and 1-year case-fatality rates were 51%, 60%, and 64%, respectively. Increased Charlson co-morbidity index, presence of liver disease, higher APACHE II score, septic shock, and need for continuous renal replacement therapy were independently associated with death at 1 year. Renal recovery occurred in 78% (68/87) of survivors at 1 year. Conclusion sARF is common and males, older patients, and those with underlying medical conditions are at greatest risk. Although the majority of patients with sARF will die, most survivors will become independent from renal replacement therapy within a year. PMID:16280066

  10. Long-term trends and patterns of fatal traumatic brain injuries in the pediatric and adolescent population of austria in 1980-2012: analysis of 33 years.

    PubMed

    Majdan, Marek; Mauritz, Walter; Rusnak, Martin; Brazinova, Alexandra; Rehorcikova, Veronika; Leitgeb, Johannes

    2014-06-01

    Traumatic brain injuries (TBIs) are of special concern in the pediatric and adolescent population because of high incidence, mortality, and potential years of life lost (PYLL). Knowledge on causes and mortality trends is essential for effective prevention. The aim of this study was to analyze the long-term trends and causes of TBI-related mortality between 1980 and 2012 in the pediatric and adolescent populations of Austria. Death certificate data on TBI-related deaths of children and adolescents 0-19 years of age and exact population numbers were obtained from the Austrian Statistical Office. Five age groups were created. Mortality trends and causes of TBI were analyzed. PYLL were used to indicate the public health impact. Of 5319 identified TBI-related deaths, 75% were male victims. The annual mortality rates per 100,000 between 1980 and 2012 decreased from 25 to 2.6 in males, from 8.5 to 1.0 in females, and from 16.9 to 1.8 in the total population. Those 15-19 years of age had the highest mortalities, followed by 0-2 years of age. Over 80% of deaths were caused by accidents, inflicted TBIs were most common in those 0-2 years of age, and traffic accidents in those 15-19 years of age. In the studied period, 295,793 PYLL could be attributed to TBIs. Measures to prevent traffic accidents contributed significantly to the decrease of mortality and PYLL, especially in 15- to 19-year-old men. Causes and trends of TBI-related mortality exhibit age-group-specific patterns, and this knowledge could contribute to planning further preventive action to reduce TBI fatalities in the studied population.

  11. Life after childhood cancer: marriage and offspring in adult long-term survivors--a population-based study in the Piedmont region, Italy.

    PubMed

    Dama, Elisa; Maule, Milena M; Mosso, Maria L; Alessi, Daniela; Ghisleni, Micaela; Pivetta, Emanuele; Pisani, Paola; Magnani, Corrado; Pastore, Guido; Merletti, Franco

    2009-11-01

    The majority of childhood cancer cases survive to adulthood. We describe the experience of marriage and reproduction as indicators of quality of life, in a population-based cohort of adult long-term survivors after early cancer reported to the Childhood Cancer Registry of Piedmont. The study included 1237 survivors with a malignant neoplasm diagnosed during 1967-2000 when aged 0-14 years, who attained age 18 years. Vital and marital status and number of offspring were assessed through the Vital Statistics Offices. Marriage and fertility deficits were estimated by comparison with the Piedmont population. Among the individuals included in this study, 919 (74.3%) never married and never lived as married. The marriage deficit was 32% [observed/expected 0.68; 95% confidence interval (CI): 0.55-0.83] in men and 18% (observed/expected 0.82; 95% CI: 0.68-0.98) in women. A total of 179 children were born to 120 women, with a fertility deficit of 41% (observed/expected 0.59; 95% CI: 0.51-0.69). In conclusion, the observed decrements in marriage in men and women and fertility in women suggest that efforts should be made to improve the recovery from physical and psychological traumas related to diagnosis and treatment of cancer.

  12. Stochastic dispersal and population persistence in marine organisms.

    PubMed

    Williams, Paul David; Hastings, Alan

    2013-08-01

    Temporally variable conditions introduce time dependence into vital rates, and predicting the effect of this variability on population dynamics and persistence is critical for the effective management of natural populations subject to fluctuating environments. In many marine species, dispersal during the larval stage establishes links among populations and is largely determined by temporally variable fluid dynamic processes. However, the consequences of time-dependent dispersal for population persistence are largely unexplored, and so we present a model of stochastically driven dispersal to study population persistence in a temporally variable, patchy habitat. We illustrate how patterns of temporal autocorrelation, expressed as variance in stochastic population connectivity, can have counterintuitive consequences for predictions, where switching between two sets of dynamics, each of which leads to extinction, can promote metapopulation persistence. We contend that accounting for stochastic dispersal can have great relevance for understanding population persistence, in marine populations in particular and in organisms with some degree of passive dispersal in general. PMID:23852360

  13. Long-Term Blood Pressure Variability, New-Onset Diabetes Mellitus, and New-Onset Chronic Kidney Disease in the Japanese General Population.

    PubMed

    Yano, Yuichiro; Fujimoto, Shouichi; Kramer, Holly; Sato, Yuji; Konta, Tsuneo; Iseki, Kunitoshi; Iseki, Chiho; Moriyama, Toshiki; Yamagata, Kunihiro; Tsuruya, Kazuhiko; Narita, Ichiei; Kondo, Masahide; Kimura, Kenjiro; Asahi, Koichi; Kurahashi, Issei; Ohashi, Yasuo; Watanabe, Tsuyoshi

    2015-07-01

    Whether long-term blood pressure (BP) variability among individuals without diabetes mellitus is associated with new-onset chronic kidney disease (CKD) risk, independently of other BP parameters (eg, mean BP, cumulative exposure to BP) and metabolic profile changes during follow-up, remains uncertain. We used data from a nationwide study of 48 587 Japanese adults aged 40 to 74 years (mean age, 61.7 years; 39% men) without diabetes mellitus or CKD (estimated glomerular filtration rate <60 mL/min per 1.73 m2 or proteinuria by dipstick). BP was measured at baseline and during 3 annual follow-up visits (4 visits). BP variability was defined as standard deviation (SD) and average real variability during the 4 visits. At the year 3 follow-up visit, 6.3% of the population had developed CKD. In multivariable-adjusted logistic regression models, 1 SD increases in SDSBP (per 5 mmHg), SDDBP (per 3 mmHg), average real variabilitySBP (per 6 mmHg), and average real variabilityDBP (per 4 mmHg) were associated with new-onset CKD (odds ratios [ORs] and 95% confidence intervals, 1.15 [1.11-1.20], 1.08 [1.04-1.12], 1.13 [1.09-1.17], 1.06 [1.02-1.10], respectively; all P<0.01) after adjustment for clinical characteristics, and with mean BP from year 0 to year 3. The associations of SDBP and average real variabilityBP with CKD remained significant after additional adjustments for metabolic parameter changes during follow-up (ORs, 1.06-1.15; all P<0.01). Sensitivity analyses by sex, antihypertensive medication use, and the presence of hypertension showed similar conclusions. Among those in the middle-aged and elderly general population without diabetes mellitus, long-term BP variability during 3 years was associated with new-onset CKD risk, independently of mean or cumulative exposure to BP and metabolic profile changes during follow-up.

  14. Distribution of population-averaged observables in stochastic gene expression.

    PubMed

    Bhattacharyya, Bhaswati; Kalay, Ziya

    2014-01-01

    Observation of phenotypic diversity in a population of genetically identical cells is often linked to the stochastic nature of chemical reactions involved in gene regulatory networks. We investigate the distribution of population-averaged gene expression levels as a function of population, or sample, size for several stochastic gene expression models to find out to what extent population-averaged quantities reflect the underlying mechanism of gene expression. We consider three basic gene regulation networks corresponding to transcription with and without gene state switching and translation. Using analytical expressions for the probability generating function of observables and large deviation theory, we calculate the distribution and first two moments of the population-averaged mRNA and protein levels as a function of model parameters, population size, and number of measurements contained in a data set. We validate our results using stochastic simulations also report exact results on the asymptotic properties of population averages which show qualitative differences among different models. PMID:24580265

  15. Dynamics of coastal cod populations: intra- and intercohort density dependence and stochastic processes

    PubMed Central

    Stenseth, N. C.; rnstad, O. N. Bj; Falck, W.; Fromentin, J.-M.; ter, J. Gj s; Gray, J. S.

    1999-01-01

    Skagerrak populations of Atlantic cod (Gadus morhua L.) have been surveyed at several fixed stations since 1919. These coastal populations consist of local stocks with a low age of maturity and a short life span. We investigated 60 time-series of 0-group juveniles (i.e. young of the year) sampled annually from 1945 to 1994. An age-structured model was developed which incorporates asymmetrical interactions between the juvenile cohorts (0-group and 1-group; i.e. one-year-old juveniles) and stochastic reproduction. The model was expressed in delay coordinates in order to estimate model parameters directly from the time-series and thereby test the model predictions. The autocovariance structure of the time-series was consistent with the delay coordinates model superimposed upon a long-term trend. The model illustrates how both regulatory (density-dependent) and disruptive (stochastic) forces are crucial in shaping the dynamics of the coastal cod populations. The age-structured life cycle acts to resonance the stochasticity inherent in the recruitment process.

  16. Long-term trends in survival of a declining population: the case of the little owl (Athene noctua) in the Netherlands.

    PubMed

    Le Gouar, Pascaline J; Schekkerman, Hans; van der Jeugd, Henk P; Boele, Arjan; van Harxen, Ronald; Fuchs, Piet; Stroeken, Pascal; van Noordwijk, Arie J

    2011-06-01

    The little owl (Athene noctua) has declined significantly in many parts of Europe, including the Netherlands. To understand the demographic mechanisms underlying their decline, we analysed all available Dutch little owl ringing data. The data set spanned 35 years, and included more than 24,000 ringed owls, allowing detailed estimation of survival rates through multi-state capture-recapture modelling taking dispersal into account. We investigated geographical and temporal variation in age-specific survival rates and linked annual survival estimates to population growth rate in corresponding years, as well as to environmental covariates. The best model for estimating survival assumed time effects on both juvenile and adult survival rates, with average annual survival estimated at 0.258 (SE = 0.047) and 0.753 (SE = 0.019), respectively. Juvenile survival rates decreased with time whereas adult survival rates fluctuated regularly among years, low survival occurring about every 4 years. Years when the population declined were associated with low juvenile survival. More than 60% of the variation in juvenile survival was explained by the increase in road traffic intensity or in average temperature in spring, but these correlations rather reflect a gradual decrease in juvenile survival coinciding with long-term global change than direct causal effects. Surprisingly, vole dynamics did not explain the cyclic dynamics of adult survival rate. Instead, dry and cold years led to low adult survival rates. Low juvenile survival rates, that limit recruitment of first-year breeders, and the regular occurrence of years with poor adult survival, were the most important determinants of the population decline of the little owl.

  17. Stochastic switching induced adaptation in a starved Escherichia coli population.

    PubMed

    Shimizu, Yoshihiro; Tsuru, Saburo; Ito, Yoichiro; Ying, Bei-Wen; Yomo, Tetsuya

    2011-01-01

    Population adaptation can be determined by stochastic switching in living cells. To examine how stochastic switching contributes to the fate decision for a population under severe stress, we constructed an Escherichia coli strain crucially dependent on the expression of a rewired gene. The gene essential for tryptophan biosynthesis, trpC, was removed from the native regulatory unit, the Trp operon, and placed under the extraneous control of the lactose utilisation network. Bistability of the network provided the cells two discrete phenotypes: the induced and suppressed level of trpC. The two phenotypes permitted the cells to grow or not, respectively, under conditions of tryptophan depletion. We found that stochastic switching between the two states allowed the initially suppressed cells to form a new population with induced trpC in response to tryptophan starvation. However, the frequency of the transition from suppressed to induced state dropped off dramatically in the starved population, in comparison to that in the nourished population. This reduced switching rate was compensated by increasing the initial population size, which probably provided the cell population more chances to wait for the rarely appearing fit cells from the unfit cells. Taken together, adaptation of a starved bacterial population because of stochasticity in the gene rewired from the ancient regulon was experimentally confirmed, and the nutritional status and the population size played a great role in stochastic adaptation. PMID:21931628

  18. Side population cells from long-term passage non-small cell lung cancer cells display loss of cancer stem cell-like properties and chemoradioresistance

    PubMed Central

    Gu, Hao; Wu, Xin-Yu; Fan, Rui-Tai; Wang, Xin; Guo, You-Zhong; Wang, Rui

    2016-01-01

    The side population (SP) assay is a widely used method for isolating stem cell-like cells from cancer cell lines and primary cells. The cancer cells used in different laboratories have been passaged for different generations. Emerging evidence revealed that repeated passaging of cell lines for multiple generations frequently leads to change of characteristics. Thus, it is worth investigating the effects of repeated passaging on the biological and functional properties of the enriched SP fraction from early- and late-passage cells. The present study reports that the cancer stem cell (CSC) characteristics, including increased frequency of tumor-initiating and self-renewal capacity, and resistance to the chemotherapy agent doxorubicin and ionizing radiation, was diminished in SP cells from late-passage non-small cell lung cancer (NSCLC) cells. This finding revealed that the SP from long-term passage NSCLC cells was not consistently enriched for stem cell-like cancer cells, and low-passage cell lines and primary cancer cells are therefore recommended in the CSCs field.

  19. Long-term radiation-related health effects in a unique human population: lessons learned from the atomic bomb survivors of Hiroshima and Nagasaki.

    PubMed

    Douple, Evan B; Mabuchi, Kiyohiko; Cullings, Harry M; Preston, Dale L; Kodama, Kazunori; Shimizu, Yukiko; Fujiwara, Saeko; Shore, Roy E

    2011-03-01

    For 63 years scientists in the Atomic Bomb Casualty Commission and its successor, the Radiation Effects Research Foundation, have been assessing the long-term health effects in the survivors of the atomic bombings of Hiroshima and Nagasaki and in their children. The identification and follow-up of a large population (approximately a total of 200,000, of whom more than 40% are alive today) that includes a broad range of ages and radiation exposure doses, and healthy representatives of both sexes; establishment of well-defined cohorts whose members have been studied longitudinally, including some with biennial health examinations and a high survivor-participation rate; and careful reconstructions of individual radiation doses have resulted in reliable excess relative risk estimates for radiation-related health effects, including cancer and noncancer effects in humans, for the benefit of the survivors and for all humankind. This article reviews those risk estimates and summarizes what has been learned from this historic and unique study.

  20. Long-term Radiation-Related Health Effects in a Unique Human Population: Lessons Learned from the Atomic Bomb Survivors of Hiroshima and Nagasaki

    PubMed Central

    Douple, Evan B.; Mabuchi, Kiyohiko; Cullings, Harry M.; Preston, Dale L.; Kodama, Kazunori; Shimizu, Yukiko; Fujiwara, Saeko; Shore, Roy E.

    2014-01-01

    For 63 years scientists in the Atomic Bomb Casualty Commission and its successor, the Radiation Effects Research Foundation, have been assessing the long-term health effects in the survivors of the atomic bombings of Hiroshima and Nagasaki and in their children. The identification and follow-up of a large population (approximately a total of 200 000, of whom more than 40% are alive today) that includes a broad range of ages and radiation exposure doses, and healthy representatives of both sexes; establishment of well-defined cohorts whose members have been studied longitudinally, including some with biennial health examinations and a high survivor participation rate; and careful reconstructions of individual radiation doses have resulted in reliable excess relative risk estimates for radiation-related health effects, including cancer and noncancer effects in humans, for the benefit of the survivors and for all humankind. This article reviews those risk estimates and summarizes what has been learned from this historic and unique study. PMID:21402804

  1. Long-term radiation-related health effects in a unique human population: lessons learned from the atomic bomb survivors of Hiroshima and Nagasaki.

    PubMed

    Douple, Evan B; Mabuchi, Kiyohiko; Cullings, Harry M; Preston, Dale L; Kodama, Kazunori; Shimizu, Yukiko; Fujiwara, Saeko; Shore, Roy E

    2011-03-01

    For 63 years scientists in the Atomic Bomb Casualty Commission and its successor, the Radiation Effects Research Foundation, have been assessing the long-term health effects in the survivors of the atomic bombings of Hiroshima and Nagasaki and in their children. The identification and follow-up of a large population (approximately a total of 200,000, of whom more than 40% are alive today) that includes a broad range of ages and radiation exposure doses, and healthy representatives of both sexes; establishment of well-defined cohorts whose members have been studied longitudinally, including some with biennial health examinations and a high survivor-participation rate; and careful reconstructions of individual radiation doses have resulted in reliable excess relative risk estimates for radiation-related health effects, including cancer and noncancer effects in humans, for the benefit of the survivors and for all humankind. This article reviews those risk estimates and summarizes what has been learned from this historic and unique study. PMID:21402804

  2. Long-term cardiovascular outcomes and overall survival of early-stage breast cancer patients with early discontinuation of trastuzumab: a population-based study.

    PubMed

    Gong, Inna Y; Verma, Sunil; Yan, Andrew T; Ko, Dennis T; Earle, Craig C; Tomlinson, George A; Trudeau, Maureen E; Krahn, Murray D; Krzyzanowska, Monika K; Brezden-Masley, Christine B; Gavura, Scott; Peacock, Stuart; Chan, Kelvin K W

    2016-06-01

    We critically examined long-term cardiovascular (CV) outcomes and overall survival (OS) of breast cancer (BC) patients who had cardiotoxicity during adjuvant trastuzumab treatment requiring discontinuation in a population-based sample. This was a retrospective cohort of early-stage BC patients diagnosed before 2010 and treated with trastuzumab in Ontario. Patients were stratified based on trastuzumab doses received: 1-8, 9-15, ≥16 (therapy completion). Time-dependent multivariable Cox models were used to analyze primary endpoint OS, and the following composite endpoints: hospitalization/emergency room visit for heart failure (HF) or death; non-HF CV (myocardial infarction, stroke) or death; and clinically significant relapse (palliative systemic therapy initiation >90 days after last trastuzumab dose) or death. Of the 3134 women, 6, 10, and 85 % received 1-8, 9-15, and ≥16 doses, respectively. Over 5-year median follow-up, early trastuzumab discontinuation was associated with more HF/death [1-8 doses hazard ratio (HR) 4.0, 95 % confidence interval (CI) 2.7-6.0; 9-15 doses HR 2.97, 95 % CI 2.1-4.3], non-HF/death (1-8 doses HR 4.3, 95 % CI 3.0-6.1; 9-15 doses HR 3.1, 95 % CI 2.2-4.4), clinically significant relapse/death (1-8 doses HR 3.1, 95 % CI 2.2-4.4; 9-15 doses HR 2.4, 95 % CI 1.8-3.3), and importantly lower OS (77, 80, 93 %; P < 0.001). Early discontinuation (1-8 doses HR 2.41, 95 % CI 1.5-3.8; 9-15 doses HR 2.9, 95 % CI 2.0-4.1) and clinically significant relapse (HR 34.0, 95 % CI 24.9-46.6) were both independent predictors of mortality. Of note, early discontinuation remained a critical independent predictor of OS even after adjusting for incident HF. Early trastuzumab discontinuation is a powerful independent predictor of cardiac events and clinically significant relapse, and both may contribute to poor survival. Both adequate cancer control and optimal CV management are required to improve long-term outcomes. PMID:27271767

  3. Long-Term Impact of Preterm Birth on Exercise Capacity in Healthy Young Men: A National Population-Based Cohort Study

    PubMed Central

    Svedenkrans, Jenny; Henckel, Ewa; Kowalski, Jan

    2013-01-01

    Background Increasing numbers of survivors of preterm birth are growing into adulthood today. Long-term health-effects of prematurity are still poorly understood, but include increased risk for diabetes, obesity and cardiovascular diseases in adult life. To test if reduced physical fitness may be a link in the causal chain of preterm birth and diseases in later life, the association of preterm birth and adult exercise capacity was investigated. The hypothesis was that preterm birth contributes independently of other risk factors to lower physical fitness in adulthood. Methods and Findings Population-based national cohort study of all males conscripting for military service in 1993–2001 and born in Sweden 1973–1983, n = 218,820. Data were retrieved from the Swedish Conscript Register, the Medical Birth Register and the Population and Housing Census 1990. Primary outcome was the results from maximal exercise test (Wmax in Watt) performed at conscription. Association to perinatal and socioeconomic risk factors, other co-variates and confounders were analysed. General linear modelling showed that preterm birth predicted low Wmax in a dose-response related pattern, with 25 Watt reduction in Wmax for the lowest gestational ages, those born ≤27 weeks. Low birth weight for gestational age also independently predicted low Wmax compared to normal and high birth weight (32 Watt reduction for those with a birth weight Standard Deviation Score <2). Low parental education was significantly associated with reduced Wmax (range 17 Watt), as well as both low and high current BMI, with severe obesity resulting in a 16 Watt deficit compared to Wmax top performance. Conclusion Being born preterm as well as being born small for gestational age predicts low exercise capacity in otherwise healthy young men. The effect size of being born preterm equal or exceed that of other known risk factors for unfitness in adults, such as low parental education and overweight. PMID:24324639

  4. Dampening prey cycle overrides the impact of climate change on predator population dynamics: a long-term demographic study on tawny owls

    PubMed Central

    Millon, Alexandre; Petty, Steve J; Little, Brian; Gimenez, Olivier; Cornulier, Thomas; Lambin, Xavier

    2014-01-01

    Predicting the dynamics of animal populations with different life histories requires careful understanding of demographic responses to multifaceted aspects of global changes, such as climate and trophic interactions. Continent-scale dampening of vole population cycles, keystone herbivores in many ecosystems, has been recently documented across Europe. However, its impact on guilds of vole-eating predators remains unknown. To quantify this impact, we used a 27-year study of an avian predator (tawny owl) and its main prey (field vole) collected in Kielder Forest (UK) where vole dynamics shifted from a high- to a low-amplitude fluctuation regime in the mid-1990s. We measured the functional responses of four demographic rates to changes in prey dynamics and winter climate, characterized by wintertime North Atlantic Oscillation (wNAO). First-year and adult survival were positively affected by vole density in autumn but relatively insensitive to wNAO. The probability of breeding and number of fledglings were higher in years with high spring vole densities and negative wNAO (i.e. colder and drier winters). These functional responses were incorporated into a stochastic population model. The size of the predator population was projected under scenarios combining prey dynamics and winter climate to test whether climate buffers or alternatively magnifies the impact of changes in prey dynamics. We found the observed dampening vole cycles, characterized by low spring densities, drastically reduced the breeding probability of predators. Our results illustrate that (i) change in trophic interactions can override direct climate change effect; and (ii) the demographic resilience entailed by longevity and the occurrence of a floater stage may be insufficient to buffer hypothesized environmental changes. Ultimately, dampened prey cycles would drive our owl local population towards extinction, with winter climate regimes only altering persistence time. These results suggest that other

  5. Dampening prey cycle overrides the impact of climate change on predator population dynamics: a long-term demographic study on tawny owls.

    PubMed

    Millon, Alexandre; Petty, Steve J; Little, Brian; Gimenez, Olivier; Cornulier, Thomas; Lambin, Xavier

    2014-06-01

    Predicting the dynamics of animal populations with different life histories requires careful understanding of demographic responses to multifaceted aspects of global changes, such as climate and trophic interactions. Continent-scale dampening of vole population cycles, keystone herbivores in many ecosystems, has been recently documented across Europe. However, its impact on guilds of vole-eating predators remains unknown. To quantify this impact, we used a 27-year study of an avian predator (tawny owl) and its main prey (field vole) collected in Kielder Forest (UK) where vole dynamics shifted from a high- to a low-amplitude fluctuation regime in the mid-1990s. We measured the functional responses of four demographic rates to changes in prey dynamics and winter climate, characterized by wintertime North Atlantic Oscillation (wNAO). First-year and adult survival were positively affected by vole density in autumn but relatively insensitive to wNAO. The probability of breeding and number of fledglings were higher in years with high spring vole densities and negative wNAO (i.e. colder and drier winters). These functional responses were incorporated into a stochastic population model. The size of the predator population was projected under scenarios combining prey dynamics and winter climate to test whether climate buffers or alternatively magnifies the impact of changes in prey dynamics. We found the observed dampening vole cycles, characterized by low spring densities, drastically reduced the breeding probability of predators. Our results illustrate that (i) change in trophic interactions can override direct climate change effect; and (ii) the demographic resilience entailed by longevity and the occurrence of a floater stage may be insufficient to buffer hypothesized environmental changes. Ultimately, dampened prey cycles would drive our owl local population towards extinction, with winter climate regimes only altering persistence time. These results suggest that other

  6. Dampening prey cycle overrides the impact of climate change on predator population dynamics: a long-term demographic study on tawny owls.

    PubMed

    Millon, Alexandre; Petty, Steve J; Little, Brian; Gimenez, Olivier; Cornulier, Thomas; Lambin, Xavier

    2014-06-01

    Predicting the dynamics of animal populations with different life histories requires careful understanding of demographic responses to multifaceted aspects of global changes, such as climate and trophic interactions. Continent-scale dampening of vole population cycles, keystone herbivores in many ecosystems, has been recently documented across Europe. However, its impact on guilds of vole-eating predators remains unknown. To quantify this impact, we used a 27-year study of an avian predator (tawny owl) and its main prey (field vole) collected in Kielder Forest (UK) where vole dynamics shifted from a high- to a low-amplitude fluctuation regime in the mid-1990s. We measured the functional responses of four demographic rates to changes in prey dynamics and winter climate, characterized by wintertime North Atlantic Oscillation (wNAO). First-year and adult survival were positively affected by vole density in autumn but relatively insensitive to wNAO. The probability of breeding and number of fledglings were higher in years with high spring vole densities and negative wNAO (i.e. colder and drier winters). These functional responses were incorporated into a stochastic population model. The size of the predator population was projected under scenarios combining prey dynamics and winter climate to test whether climate buffers or alternatively magnifies the impact of changes in prey dynamics. We found the observed dampening vole cycles, characterized by low spring densities, drastically reduced the breeding probability of predators. Our results illustrate that (i) change in trophic interactions can override direct climate change effect; and (ii) the demographic resilience entailed by longevity and the occurrence of a floater stage may be insufficient to buffer hypothesized environmental changes. Ultimately, dampened prey cycles would drive our owl local population towards extinction, with winter climate regimes only altering persistence time. These results suggest that other

  7. Mycorrhizal diversity, seed germination and long-term changes in population size across nine populations of the terrestrial orchid Neottia ovata.

    PubMed

    Jacquemyn, Hans; Waud, Michael; Merckx, Vincent S F T; Lievens, Bart; Brys, Rein

    2015-07-01

    In plant species that rely on mycorrhizal symbioses for germination and seedling establishment, seedling recruitment and temporal changes in abundance can be expected to depend on fungal community composition and local environmental conditions. However, disentangling the precise factors that determine recruitment success in species that critically rely on mycorrhizal fungi represents a major challenge. In this study, we used seed germination experiments, 454 amplicon pyrosequencing and assessment of soil conditions to investigate the factors driving changes in local abundance in 28 populations of the orchid Neottia ovata. Comparison of population sizes measured in 2003 and 2013 showed that nearly 60% of the studied populations had declined in size (average growth rate across all populations: -0.01). Investigation of the mycorrhizal fungi in both the roots and soil revealed a total of 68 species of putatively mycorrhizal fungi, 21 of which occurred exclusively in roots, 25 that occurred solely in soil and 22 that were observed in both the soil and roots. Seed germination was limited and significantly and positively related to soil moisture content and soil pH, but not to fungal community composition. Large populations or populations with high population growth rates showed significantly higher germination than small populations or populations declining in size, but no significant relationships were found between population size or growth and mycorrhizal diversity. Overall, these results indicate that temporal changes in abundance were related to the ability of seeds to germinate, but at the same time they provided limited evidence that variation in fungal communities played an important role in determining population dynamics.

  8. Mycorrhizal diversity, seed germination and long-term changes in population size across nine populations of the terrestrial orchid Neottia ovata.

    PubMed

    Jacquemyn, Hans; Waud, Michael; Merckx, Vincent S F T; Lievens, Bart; Brys, Rein

    2015-07-01

    In plant species that rely on mycorrhizal symbioses for germination and seedling establishment, seedling recruitment and temporal changes in abundance can be expected to depend on fungal community composition and local environmental conditions. However, disentangling the precise factors that determine recruitment success in species that critically rely on mycorrhizal fungi represents a major challenge. In this study, we used seed germination experiments, 454 amplicon pyrosequencing and assessment of soil conditions to investigate the factors driving changes in local abundance in 28 populations of the orchid Neottia ovata. Comparison of population sizes measured in 2003 and 2013 showed that nearly 60% of the studied populations had declined in size (average growth rate across all populations: -0.01). Investigation of the mycorrhizal fungi in both the roots and soil revealed a total of 68 species of putatively mycorrhizal fungi, 21 of which occurred exclusively in roots, 25 that occurred solely in soil and 22 that were observed in both the soil and roots. Seed germination was limited and significantly and positively related to soil moisture content and soil pH, but not to fungal community composition. Large populations or populations with high population growth rates showed significantly higher germination than small populations or populations declining in size, but no significant relationships were found between population size or growth and mycorrhizal diversity. Overall, these results indicate that temporal changes in abundance were related to the ability of seeds to germinate, but at the same time they provided limited evidence that variation in fungal communities played an important role in determining population dynamics. PMID:25963669

  9. Long-term Direct Costs Before and After Proctocolectomy for Ulcerative Colitis: A Population-based Study in Olmsted County, Minnesota

    PubMed Central

    Holubar, Stefan D.; Long, Kirsten Hall; Loftus, Edward V.; Wolff, Bruce G.; Pemberton, John H.; Cima, Robert R.

    2009-01-01

    PURPOSE We hypothesized that patients undergoing definitive surgery for chronic ulcerative colitis have reduced direct medical costs after, as compared with before, total proctocolectomy. METHODS A population-based cohort who underwent proctocolectomy for ulcerative colitis from 1988–2007 was identified using the Rochester Epidemiology Project. Total direct healthcare costs were estimated from an administrative database. The primary outcome was the observed cost difference between a 2-year period before surgery and the 2-year period after a surgery/recovery period (surgery+180 days). Statistical significance was assessed using paired t-tests and bootstrapping methods. Demographic data were presented as median (interquartile range) or frequency (proportion). Mean costs are reported in 2007 constant dollars. RESULTS Sixty patients were Olmsted County, Minnesota residents at operation and for the entire period of obervation. Overall 40 patients (66%) were men, median age of 42 years (31–52), median colitis duration of 4 years (1–11). Operations included ileal-pouch anal anastomosis (n=45, mean cost of surgery/recovery period $50,530) or total proctocolectomy with Brooke ileostomy (n=15, mean cost of surgery/recovery period $39,309). In the pouch subgroup, direct medical costs on average were reduced by $9,296 (P<0.001, bootstrapped 95% CI: $324 to $15,628) in the 2-years after recovery. In the Brooke ileostomy subgroup, direct medical costs on average were reduced by $12,529 (P<0.001, bootstrapped 95% CI: $6467 to $18,688) in the 2-years after recovery. CONCLUSIONS Surgery for chronic ulcerative colitis resulted in reduced direct costs in the 2-years after surgical recovery. These observations suggest that surgical intervention for ulcerative colitis is associated with long-term economic benefit. PMID:19966626

  10. Long-term healthcare use and costs in patients with stable coronary artery disease: a population-based cohort using linked health records (CALIBER)

    PubMed Central

    Walker, Simon; Asaria, Miqdad; Manca, Andrea; Palmer, Stephen; Gale, Chris P.; Shah, Anoop Dinesh; Abrams, Keith R.; Crowther, Michael; Timmis, Adam; Hemingway, Harry; Sculpher, Mark

    2016-01-01

    Aims To examine long-term healthcare utilization and costs of patients with stable coronary artery disease (SCAD). Methods and results Linked cohort study of 94 966 patients with SCAD in England, 1 January 2001 to 31 March 2010, identified from primary care, secondary care, disease, and death registries. Resource use and costs, and cost predictors by time and 5-year cardiovascular disease (CVD) risk profile were estimated using generalized linear models. Coronary heart disease hospitalizations were 20.5% in the first year and 66% in the year following a non-fatal (myocardial infarction, ischaemic or haemorrhagic stroke) event. Mean healthcare costs were £3133 per patient in the first year and £10 377 in the year following a non-fatal event. First-year predictors of cost included sex (mean cost £549 lower in females), SCAD diagnosis (non-ST-elevation myocardial infarction cost £656 more than stable angina), and co-morbidities (heart failure cost £657 more per patient). Compared with lower risk patients (5-year CVD risk 3.5%), those of higher risk (5-year CVD risk 44.2%) had higher 5-year costs (£23 393 vs. £9335) and lower lifetime costs (£43 020 vs. £116 888). Conclusion Patients with SCAD incur substantial healthcare utilization and costs, which varies and may be predicted by 5-year CVD risk profile. Higher risk patients have higher initial but lower lifetime costs than lower risk patients as a result of shorter life expectancy. Improved cardiovascular survivorship among an ageing CVD population is likely to require stratified care in anticipation of the burgeoning demand. PMID:27042338

  11. A Survey of Very-Long-Term Outcomes after Traumatic Brain Injury among Members of a Population-Based Incident Cohort

    PubMed Central

    Moessner, Anne M.; Mandrekar, Jay; Diehl, Nancy N.; Leibson, Cynthia L.; Malec, James F.

    2011-01-01

    Abstract To assess quality of life and barriers to participation in vocational and community life for persons with traumatic brain injury (TBI) over the very-long term, a population-based cohort was identified in Olmsted County, Minnesota; 1623 individuals were identified as having experienced a confirmed TBI while a resident of Olmsted County, Minnesota, during the period from 1935–2000. A survey was sent to eligible individuals that included elements of standardized instruments addressing health status and disability, and questions that assessed issues important to successful social reintegration after TBI. Of 1623 eligible participants sent surveys, 605 responded (37% response rate). Thirty-nine percent of respondents were female and 79% had mild injuries. Mean age at injury was 30.8 years, and mean years since injury was 28.8. Overall, respondents reported living in the community; the majority were married and had achieved education beyond high school. Problems with memory, thinking, and physical and emotional health were most often reported. Respondents reported low levels of depression and anxiety, and high levels of satisfaction with life. Seventy-three percent of respondents reported no problems that they attributed to their TBI. Increasing injury severity was associated with a significant risk of reporting injury-related problems at survey completion. Respondents with a longer time since injury were less likely to report any TBI-related problems. These results indicate that self-reported outcomes and adaptation to impairment-related limitations improve as the time since injury increases. These findings highlight the importance of providing coordinated medical rehabilitation and community-based support services to promote positive outcomes over the life span after TBI. PMID:21121813

  12. Long-term prognostic value of blood pressure variability in the general population: results of the Pressioni Arteriose Monitorate e Loro Associazioni Study.

    PubMed

    Mancia, Giuseppe; Bombelli, Michele; Facchetti, Rita; Madotto, Fabiana; Corrao, Giovanni; Trevano, Fosca Quarti; Grassi, Guido; Sega, Roberto

    2007-06-01

    The hypothesis has been advanced that cardiovascular prognosis is related not only to 24-hour mean blood pressure but also to blood pressure variability. Data, however, are inconsistent, and no long-term prognostic study is available. In 2012 individuals randomly selected from the population of Monza (Milan), 24-hour ambulatory blood pressure (Spacelabs 90207) was measured via readings spaced by 20 minutes. Systolic and diastolic blood pressure variability was obtained by calculating the following: (1) the SD of 24-hour, day, and night mean values; (2) the day-night blood pressure difference; and (3) the residual or erratic blood pressure variability (Fourier spectral analysis). Fatal cardiovascular and noncardiovascular events were registered for 148 months. When adjusted for age, sex, 24-hour mean blood pressure, and other risk factors, there was no relationship between the risk of death and 24-hour, day, and night blood pressure SDs. In contrast, the adjusted risk of cardiovascular death was inversely related to day-night diastolic BP difference (beta coefficient=-0.040; P<0.02) and showed a significant positive relationship with residual diastolic blood pressure variability (beta coefficient=0.175; P<0.002). Twenty-four-hour mean blood pressure attenuation of nocturnal hypotension and erratic diastolic blood pressure variability all independently predicted the mortality risk, with the erratic variability being the most important factor. Our data show that the relationship of blood pressure to prognosis is complex and that phenomena other than 24-hour mean values are involved. They also provide the first evidence that short-term erratic components of blood pressure variability play a prognostic role, with their increase being accompanied by an increased cardiovascular risk. PMID:17452502

  13. Genetic and environmental contributions to long-term sick leave and disability pension: a population-based study of young adult Norwegian twins.

    PubMed

    Gjerde, Line C; Knudsen, Gun Peggy; Czajkowski, Nikolai; Gillespie, Nathan; Aggen, Steven H; Røysamb, Espen; Reichborn-Kjennerud, Ted; Tambs, Kristian; Kendler, Kenneth S; Orstavik, Ragnhild E

    2013-08-01

    Although exclusion from the workforce due to long-term sick leave (LTSL) and disability pension (DP) is a major problem in many Western countries, the etiology of LTSL and DP is not well understood. These phenomena have a strong association as most patients receiving DP have first been on LTSL. However, only a few of those on LTSL end up with DP. The present study aimed to investigate the common and specific genetic and environmental risk factors for LTSL and DP. The present study utilizes a population-based sample of 7,710 young adult twins from the Norwegian Institute of Public Health Twin Panel, which has been linked to the Historical-Event Database (FD-Trygd; 1998-2008). Univariate and bivariate twin models were fitted to determine to what degree genetic and environmental factors contribute to variation in LTSL and DP. The estimated heritabilities of LTSL and DP were 0.49 and 0.66, respectively. There was no evidence for shared environmental or sex-specific factors. The phenotypic-, genetic-, and non-familial environmental correlations between the variables were 0.86, 0.82, and 0.94, respectively. Our results indicate that familial transmission of LTSL and DP is due to genetic and not environmental factors. The risk factors contributing to LTSL and DP were mainly shared, suggesting that what increases risk for LTSL also increases risk for DP. However, a non-negligible part of the genetic variance was not shared between the variables, which may contribute to explaining why some progress from LTSL to DP, whereas others return to work.

  14. Information exchange between short term and long term operations

    NASA Astrophysics Data System (ADS)

    Weijs, Steven

    2016-04-01

    This research focuses on the interactions between optimal short term and long term operations of managed water systems. Stochastic Dynamic Programming is used as a framework to find and analyze optimal operations. When considering optimal operations under uncertainty, the short term operations are influenced by the long term optimal policy through the value function of the end-state at the short term horizon. Conversely, the optimal long-term operations are influenced by the value of future decisions, which is partly determined by the short term operations. This leads to a two-way information flow between short and long term operations. The implications of this information flow are discussed.

  15. Important factors governing exposure of the population and countermeasure application in rural settlements of the Russian Federation in the long-term after the Chernobyl accident.

    PubMed

    Fesenko, S; Jacob, P; Alexakhin, R; Sanzharova, N I; Panov, A; Fesenko, G; Cecille, L

    2001-01-01

    Rural settlements located in areas of the Russian Federation contaminated after the Chernobyl accident and exceeding an annual dose of 1 mSv a-1 have been classified according to 137Cs contamination density, internal dose and the neighbourhood of forests. It has been shown that, with the exception of the most contaminated areas, the internal doses decreased in accordance with a decline in 137Cs availability for plant root uptake. An inverse tendency was observed in areas with 137Cs contamination above 555 kBq m-2 which can be explained by a reduction or even termination of countermeasure application and by an increasing consumption of forest products in areas where restrictive countermeasures are still implemented. Twenty-seven settlements have been studied to estimate the effectiveness of countermeasures applied previously and to identify the most important factors governing the radiation exposure to the population and its change with time. It has been shown that the effectiveness of countermeasures which resulted in a decrease of up to 40% of doses has a tendency to decline in the long term. The need for continuation of remediation in rural settlements was evaluated both for selected settlements and extrapolated to the whole contaminated area and it has been shown that the application of countermeasures will be of importance at least up to the year 2045. Rather high effectiveness in terms of internal dose reduction (factor of 2-2.5) of radical improvement (disking, ploughing and reseeding) and administration of Cs binders to animals (Ferrocyn) was demonstrated for the selected settlements. It could be demonstrated that for forest-remote settlements there is a linear dependence between internal dose normalised to the density of contamination and the proportion of peat soils around settlements. For near-forest settlements, this dependence was less pronounced which can be explained by the high contribution of forest food products to the internal dose. Milk is still

  16. Stochastic solution of population balance equations for reactor networks

    SciTech Connect

    Menz, William J.; Akroyd, Jethro; Kraft, Markus

    2014-01-01

    This work presents a sequential modular approach to solve a generic network of reactors with a population balance model using a stochastic numerical method. Full-coupling to the gas-phase is achieved through operator-splitting. The convergence of the stochastic particle algorithm in test networks is evaluated as a function of network size, recycle fraction and numerical parameters. These test cases are used to identify methods through which systematic and statistical error may be reduced, including by use of stochastic weighted algorithms. The optimal algorithm was subsequently used to solve a one-dimensional example of silicon nanoparticle synthesis using a multivariate particle model. This example demonstrated the power of stochastic methods in resolving particle structure by investigating the transient and spatial evolution of primary polydispersity, degree of sintering and TEM-style images. Highlights: •An algorithm is presented to solve reactor networks with a population balance model. •A stochastic method is used to solve the population balance equations. •The convergence and efficiency of the reported algorithms are evaluated. •The algorithm is applied to simulate silicon nanoparticle synthesis in a 1D reactor. •Particle structure is reported as a function of reactor length and time.

  17. Long-term home care research.

    PubMed

    Green, J H

    1989-11-01

    The population of seniors is growing and health service reimbursement is shrinking. Long-term home health care services were developed with an assumption that the services would decrease costs. This assumption has not been validated. What has been recognized is that long-term home health care targets a new and growing population of frail seniors who need services but are probably not at risk for institutionalization. The impact of long-term home care services on the health status and quality of life of seniors and caregivers has been limited by outcome measurement problems. There are indications that the services improved life satisfaction and reduced services needs, but further evaluations need to replicate the outcomes. In effect, long-term outcomes have not been sufficiently explored. Further research also needs to assist us in identifying outcomes for certain services with precise target populations. Public policy questions are ahead. Should a program that can increase costs, has demonstrated some but not dramatic impacts on quality of life and health status, and has the possibility of expansion, be funded? The question is obviously debatable. From a nursing perspective of health promotion and prevention, the answer is "yes." Funding should be continued in conjunction with increased research on the program impacts. In Kane's (1988) analysis of the Channeling experiments, she summarized the situation effectively: Knowing these facts, we are now in a position to reformulate public policies to design a system of long-term care that satisfies the preferences of consumers and protects them from catastrophic long-term expenses, while promoting the triple virtues of acceptable, quality, equitable access, and defensible costs. . . Nothing in the Channeling results should prevent us from going ahead and trying to develop both community based and institutionally based long-term services in which this country can take pride.

  18. Long-term use of metformin and colorectal cancer risk in type II diabetics: a population-based case-control study.

    PubMed

    Cardel, Majken; Jensen, Sara M; Pottegård, Anton; Jørgensen, Trine L; Hallas, Jesper

    2014-10-01

    In vitro and animal studies indicate that metformin prevents colorectal cancer (CRC). Epidemiological studies, however, have been equivocal. We undertook this study to assess whether metformin prevents CRC in individuals with type II diabetes. We performed a nested case-control study restricted to Danish citizens with type II diabetes. Data were collected from four Danish nationwide registries. Cases were type II diabetics with a primary CRC between 2000 and 2009, and controls were sampled among subjects with type II diabetes. Long-term exposure to metformin was defined by the redeeming of prescriptions for a cumulative dose of 2000 g within 5 years prior to the index date. To control for potential confounders, we used unconditional logistic regression. We generated adjusted odds ratios (OR) for the association between metformin and CRC and performed subanalyses for selected subgroups and for the dose-response relation. We identified 2088 cases and 9060 controls during the study period. The association between long-term metformin use and CRC gave an adjusted OR at 0.83 (95% CI 0.68-1.00). A protective effect on CRC with long-term use of metformin was only evident for women (OR 0.66 vs. 0.99 for men). There was a significant dose-response association of metformin use >250 defined daily dose (DDD) and for the duration of metformin use >1 year. We found an indication of a protective effect of long-term metformin use against CRC in type II diabetics, although this effect was only seen in women.

  19. Long-term environmental stewardship.

    SciTech Connect

    Nagy, Michael David

    2010-08-01

    The purpose of this Supplemental Information Source Document is to effectively describe Long-Term Environmental Stewardship (LTES) at Sandia National Laboratories/New Mexico (SNL/NM). More specifically, this document describes the LTES and Long-Term Stewardship (LTS) Programs, distinguishes between the LTES and LTS Programs, and summarizes the current status of the Environmental Restoration (ER) Project.

  20. Presynaptic long-term plasticity

    PubMed Central

    Yang, Ying; Calakos, Nicole

    2013-01-01

    Long-term synaptic plasticity is a major cellular substrate for learning, memory, and behavioral adaptation. Although early examples of long-term synaptic plasticity described a mechanism by which postsynaptic signal transduction was potentiated, it is now apparent that there is a vast array of mechanisms for long-term synaptic plasticity that involve modifications to either or both the presynaptic terminal and postsynaptic site. In this article, we discuss current and evolving approaches to identify presynaptic mechanisms as well as discuss their limitations. We next provide examples of the diverse circuits in which presynaptic forms of long-term synaptic plasticity have been described and discuss the potential contribution this form of plasticity might add to circuit function. Finally, we examine the present evidence for the molecular pathways and cellular events underlying presynaptic long-term synaptic plasticity. PMID:24146648

  1. Stochastic population dynamics in astrochemistry and aerosol science

    NASA Astrophysics Data System (ADS)

    Losert-Valiente Kroon, C. M.

    Classical, non-equilibrium systems of diffusing species or entities undergoing depletion, evaporation and reaction processes are at the heart of many problems in Physics, Chemistry, Biology and Financial Mathematics. It is well known that fluctuations and correlations in statistical systems can have a profound influence on the macroscopic properties of the system. However, the traditional rate equations that describe the evolution of mean populations in time and space do not incorporate statistical fluctuations. This becomes an issue of great importance when population densities are low. In order to develop a stochastic description of birth-and-death processes beyond the mean field approximation I employ techniques in classical many-body Physics in a manner analogous to the treatment of quantum systems. I obtain promising results to understand and quantify the exact circumstances of the failure of the mean-field approximation in specific problems in Astrophysics, namely heterogeneous chemical reactions in interstellar clouds, and in Aerosol Science, namely heterogeneous nucleation processes, and deliver the means to manipulate the alternative stochastic framework according to the Doi-Peliti formalism. In this framework the mean population of a species is given by the average of a solution to a set of constraint equations over all realisations of the stochastic noise. The constraint equations are inhomogeneous stochastic partial differential equations with multiplicative real or complex Gaussian noise. In general, these equations cannot be solved analytically. Therefore I resort to the numerical implementation of the Doi-Peliti formalism. The main code is written in the GNU C language, some algebraic calculations are performed by means of the MapleV package. In the case of large population densities the stochastic framework renders the same results as the mean field approximation whereas for low population densities its predictions differ substantially from the

  2. Deterministic versus stochastic aspects of superexponential population growth models

    NASA Astrophysics Data System (ADS)

    Grosjean, Nicolas; Huillet, Thierry

    2016-08-01

    Deterministic population growth models with power-law rates can exhibit a large variety of growth behaviors, ranging from algebraic, exponential to hyperexponential (finite time explosion). In this setup, selfsimilarity considerations play a key role, together with two time substitutions. Two stochastic versions of such models are investigated, showing a much richer variety of behaviors. One is the Lamperti construction of selfsimilar positive stochastic processes based on the exponentiation of spectrally positive processes, followed by an appropriate time change. The other one is based on stable continuous-state branching processes, given by another Lamperti time substitution applied to stable spectrally positive processes.

  3. Stochastic predation events and population persistence in bighorn sheep.

    PubMed

    Festa-Bianchet, Marco; Coulson, Tim; Gaillard, Jean-Michel; Hogg, John T; Pelletier, Fanie

    2006-06-22

    Many studies have reported temporal changes in the relative importance of density-dependence and environmental stochasticity in affecting population growth rates, but they typically assume that the predominant factor limiting growth remains constant over long periods of time. Stochastic switches in limiting factors that persist for multiple time-steps have received little attention, but most wild populations may periodically experience such switches. Here, we consider the dynamics of three populations of individually marked bighorn sheep (Ovis canadensis) monitored for 24-28 years. Each population experienced one or two distinct cougar (Puma concolor) predation events leading to population declines. The onset and duration of predation events were stochastic and consistent with predation by specialist individuals. A realistic Markov chain model confirms that predation by specialist cougars can cause extinction of isolated populations. We suggest that such processes may be common. In such cases, predator-prey equilibria may only occur at large geographical and temporal scales, and are unlikely with increasing habitat fragmentation.

  4. Stochastic predation events and population persistence in bighorn sheep

    PubMed Central

    Festa-Bianchet, Marco; Coulson, Tim; Gaillard, Jean-Michel; Hogg, John T; Pelletier, Fanie

    2006-01-01

    Many studies have reported temporal changes in the relative importance of density-dependence and environmental stochasticity in affecting population growth rates, but they typically assume that the predominant factor limiting growth remains constant over long periods of time. Stochastic switches in limiting factors that persist for multiple time-steps have received little attention, but most wild populations may periodically experience such switches. Here, we consider the dynamics of three populations of individually marked bighorn sheep (Ovis canadensis) monitored for 24–28 years. Each population experienced one or two distinct cougar (Puma concolor) predation events leading to population declines. The onset and duration of predation events were stochastic and consistent with predation by specialist individuals. A realistic Markov chain model confirms that predation by specialist cougars can cause extinction of isolated populations. We suggest that such processes may be common. In such cases, predator–prey equilibria may only occur at large geographical and temporal scales, and are unlikely with increasing habitat fragmentation. PMID:16777749

  5. A core stochastic population projection model for Florida manatees (Trichechus manatus latirostris)

    USGS Publications Warehouse

    Runge, Michael C.; Sanders-Reed, Carol A.; Fonnesbeck, Christopher J.

    2007-01-01

    probability of extinction is low, the model predicts that current and emerging threats are likely to result in a long-term decline in the statewide population and a change in the regional distribution of manatees. Analyses of sensitivity and variance contribution highlight the importance of reducing uncertainty in some life-history parameters, particularly adult survival, temporal variance of adult survival, and long-term warm-water capacity. This core biological model is expected to evolve over time, as better information becomes available about manatees and their habitat, and as new assessment needs arise. We anticipate that this core model will be customized for other state and federal assessments in the near future.

  6. A core stochastic population projection model for Florida manatees (Trichechus manatus latirostris)

    USGS Publications Warehouse

    Runge, M.C.; Sanders-Reed, C.A.; Fonnesbeck, C.J.

    2007-01-01

    probability of extinction is low, the model predicts that current and emerging threats are likely to result in a long-term decline in the statewide population and a change in the regional distribution of manatees. Analyses of sensitivity and variance contribution highlight the importance of reducing uncertainty in some life-history parameters, particularly adult survival, temporal variance of adult survival, and long-term warm-water capacity. This core biological model is expected to evolve over time, as better information becomes available about manatees and their habitat, and as new assessment needs arise. We anticipate that this core model will be customized for other state and federal assessments in the near future.

  7. Modeling bacterial population growth from stochastic single-cell dynamics.

    PubMed

    Alonso, Antonio A; Molina, Ignacio; Theodoropoulos, Constantinos

    2014-09-01

    A few bacterial cells may be sufficient to produce a food-borne illness outbreak, provided that they are capable of adapting and proliferating on a food matrix. This is why any quantitative health risk assessment policy must incorporate methods to accurately predict the growth of bacterial populations from a small number of pathogens. In this aim, mathematical models have become a powerful tool. Unfortunately, at low cell concentrations, standard deterministic models fail to predict the fate of the population, essentially because the heterogeneity between individuals becomes relevant. In this work, a stochastic differential equation (SDE) model is proposed to describe variability within single-cell growth and division and to simulate population growth from a given initial number of individuals. We provide evidence of the model ability to explain the observed distributions of times to division, including the lag time produced by the adaptation to the environment, by comparing model predictions with experiments from the literature for Escherichia coli, Listeria innocua, and Salmonella enterica. The model is shown to accurately predict experimental growth population dynamics for both small and large microbial populations. The use of stochastic models for the estimation of parameters to successfully fit experimental data is a particularly challenging problem. For instance, if Monte Carlo methods are employed to model the required distributions of times to division, the parameter estimation problem can become numerically intractable. We overcame this limitation by converting the stochastic description to a partial differential equation (backward Kolmogorov) instead, which relates to the distribution of division times. Contrary to previous stochastic formulations based on random parameters, the present model is capable of explaining the variability observed in populations that result from the growth of a small number of initial cells as well as the lack of it compared to

  8. Long-Term Stability of Social Participation

    ERIC Educational Resources Information Center

    Hyyppa, Markku T.; Maki, Juhani; Alanen, Erkki; Impivaara, Olli; Aromaa, Arpo

    2008-01-01

    The long-term stability of social participation was investigated in a representative urban population of 415 men and 579 women who had taken part in the nationwide Mini-Finland Health Survey in the years 1978-1980 and were re-examined 20 years later. Stability was assessed by means of the following tracking coefficients: kappa, proportion of…

  9. Stochastic Hopf and torus bifurcations in population biology

    NASA Astrophysics Data System (ADS)

    Stollenwerk, Nico; Sommer, Pablo Fuentes; Mateus, Luis; Kooi, Bob; Aguiar, Maíra

    2016-06-01

    In population biological systems often bifurcation sequences via period doubling are observed, especially in simplest models of epidemiology like the susceptible-infected-recovered (SIR) model with seasonal forcing in the infection rate. But other routes to complex behaviour can as easily be found, for example in multi-strain models of SIR-type without forcing, here after a Hopf bifurcation a torus bifurcation leads into chaos. However, these models are already relatively high dimensional. One of the simplest models in population biology, now in ecology, is the Rosenzweig-MacArthur model, displaying a Hopf bifurcation and with forcing also a torus bifurcation leading to more complex behaviour subsequently. Here we investigate an only slightly extended version which again can be interpreted as a stochastic process of a population dynamical model. Such stochastic models give insight into what can be observed ultimately in empirical data of the systems under investigation.

  10. Stochastic resonance in a generalized Von Foerster population growth model

    SciTech Connect

    Lumi, N.; Mankin, R.

    2014-11-12

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

  11. Long-Term Use of Benzodiazepines

    PubMed Central

    Potts, Nicholas L.S.; Krishnan, K. Ranga R.

    1992-01-01

    Problems associated with physical dependence and abuse of benzodiazepines by a small percentage of patients have reduced their popularity from the most commonly prescribed psychoactive drug in the 1970s to being prescribed for mainly short periods. Patients who benefit from long-term benzodiazepine use are nearly ignored by the medical community as a whole. This article details what patient population can improve from long-term benzodiazepine therapy, the risks and benefits of treatment, and how to select appropriate candidates. PMID:21229127

  12. Long term complications of diabetes

    MedlinePlus

    ... this page: //medlineplus.gov/ency/patientinstructions/000327.htm Long term complications of diabetes To use the sharing ... sores and infections. If it goes on too long, your toes, foot, or leg may need to ...

  13. Abdominal Pain, Long-Term

    MedlinePlus

    MENU Return to Web version Abdominal Pain, Long-term See complete list of charts. Ongoing or recurrent abdominal pain, also called chronic pain, may be difficult to diagnose, causing frustration for ...

  14. Long-term biomass research

    SciTech Connect

    Not Available

    1981-03-01

    Some of DOE's long term R and D programs for biomass are summarized in this article. These include research efforts in the fields of anaerobic digestion, energy farming, short rotation cultivation and aquatic farming. (DMC)

  15. Long-term outcomes after severe shock.

    PubMed

    Pratt, Cristina M; Hirshberg, Eliotte L; Jones, Jason P; Kuttler, Kathryn G; Lanspa, Michael J; Wilson, Emily L; Hopkins, Ramona O; Brown, Samuel M

    2015-02-01

    Severe shock is a life-threatening condition with very high short-term mortality. Whether the long-term outcomes among survivors of severe shock are similar to long-term outcomes of other critical illness survivors is unknown. We therefore sought to assess long-term survival and functional outcomes among 90-day survivors of severe shock and determine whether clinical predictors were associated with outcomes. Seventy-six patients who were alive 90 days after severe shock (received ≥1 μg/kg per minute of norepinephrine equivalent) were eligible for the study. We measured 3-year survival and long-term functional outcomes using the Medical Outcomes Study 36-Item Short-Form Health Survey, the EuroQOL 5-D-3L, the Hospital Anxiety and Depression Scale, the Impact of Event Scale-Revised, and an employment instrument. We also assessed the relationship between in-hospital predictors and long-term outcomes. The mean long-term survival was 5.1 years; 82% (62 of 76) of patients survived, of whom 49 were eligible for follow-up. Patients who died were older than patients who survived. Thirty-six patients completed a telephone interview a mean of 5 years after hospital admission. The patients' Physical Functioning scores were below U.S. population norms (P < 0.001), whereas mental health scores were similar to population norms. Nineteen percent of the patients had symptoms of depression, 39% had symptoms of anxiety, and 8% had symptoms of posttraumatic stress disorder. Thirty-six percent were disabled, and 17% were working full-time. Early survivors of severe shock had a high 3-year survival rate. Patients' long-term physical and psychological outcomes were similar to those reported for cohorts of less severely ill intensive care unit survivors. Anxiety and depression were relatively common, but only a few patients had symptoms of posttraumatic stress disorder. This study supports the observation that acute illness severity does not determine long-term outcomes. Even extremely

  16. Biomonitoring short- and long-term exposure to the herbicide terbuthylazine in agriculture workers and in the general population using urine and hair specimens.

    PubMed

    Mercadante, Rosa; Polledri, Elisa; Bertazzi, Pier Alberto; Fustinoni, Silvia

    2013-10-01

    The aim of this work was to evaluate short-term and long-term exposure to terbuthylazine (TBA) in agriculture workers (AW), rural residents (RR), and urban residents (UR) using urine and hair specimens. Twelve AW, 13 RR, and 17 UR were included in the study. Urine spot samples were collected with two different protocols. AW urine samples were collected before the application season (February, U0), at bedtime on the day of TBA application (March-May, U1), and prior to the next shift on the day after TBA application (U2). RR and UR urine samples were collected on any day during the application season (Ue). Hair samples were collected for all subjects before the application season (February, H0) and at the end of the season (June, H1). TBA and its metabolite desethylterbuthylazine (DET) were measured by liquid chromatography coupled with triple quadrupole mass spectrometry detection. DET was exclusively found in urine, while TBA was mostly found in the hair. In the AW, the urinary levels of DET were not detected in the U0 samples, and they increased to median levels of 1.81 and 2.94μg/L in the U1 and U2 samples, respectively (p<0.001). In the RR and UR, DET was not detected in the Ue samples. In the UR, TBA was not detected in the H0 samples, and the median levels of TBA were 0.01ng/mg hair in both the AW and RR. In the H1 samples, the median TBA levels were not detected, 0.01, and 0.08ng/mg hair in the UR, RR, and AW, respectively (p<0.001). Urinary DET and hair TBA are promising candidates for biomonitoring short- and long-term exposure to TBA. The use of this herbicide in agriculture leads to exposure in rural residents.

  17. An examination of population exposure to traffic related air pollution: Comparing spatially and temporally resolved estimates against long-term average exposures at the home location.

    PubMed

    Shekarrizfard, Maryam; Faghih-Imani, Ahmadreza; Hatzopoulou, Marianne

    2016-05-01

    Air pollution in metropolitan areas is mainly caused by traffic emissions. This study presents the development of a model chain consisting of a transportation model, an emissions model, and atmospheric dispersion model, applied to dynamically evaluate individuals' exposure to air pollution by intersecting daily trajectories of individuals and hourly spatial variations of air pollution across the study domain. This dynamic approach is implemented in Montreal, Canada to highlight the advantages of the method for exposure analysis. The results for nitrogen dioxide (NO2), a marker of traffic related air pollution, reveal significant differences when relying on spatially and temporally resolved concentrations combined with individuals' daily trajectories compared to a long-term average NO2 concentration at the home location. We observe that NO2 exposures based on trips and activity locations visited throughout the day were often more elevated than daily NO2 concentrations at the home location. The percentage of all individuals with a lower 24-hour daily average at home compared to their 24-hour mobility exposure is 89.6%, of which 31% of individuals increase their exposure by more than 10% by leaving the home. On average, individuals increased their exposure by 23-44% while commuting and conducting activities out of home (compared to the daily concentration at home), regardless of air quality at their home location. We conclude that our proposed dynamic modelling approach significantly improves the results of traditional methods that rely on a long-term average concentration at the home location and we shed light on the importance of using individual daily trajectories to understand exposure.

  18. An examination of population exposure to traffic related air pollution: Comparing spatially and temporally resolved estimates against long-term average exposures at the home location.

    PubMed

    Shekarrizfard, Maryam; Faghih-Imani, Ahmadreza; Hatzopoulou, Marianne

    2016-05-01

    Air pollution in metropolitan areas is mainly caused by traffic emissions. This study presents the development of a model chain consisting of a transportation model, an emissions model, and atmospheric dispersion model, applied to dynamically evaluate individuals' exposure to air pollution by intersecting daily trajectories of individuals and hourly spatial variations of air pollution across the study domain. This dynamic approach is implemented in Montreal, Canada to highlight the advantages of the method for exposure analysis. The results for nitrogen dioxide (NO2), a marker of traffic related air pollution, reveal significant differences when relying on spatially and temporally resolved concentrations combined with individuals' daily trajectories compared to a long-term average NO2 concentration at the home location. We observe that NO2 exposures based on trips and activity locations visited throughout the day were often more elevated than daily NO2 concentrations at the home location. The percentage of all individuals with a lower 24-hour daily average at home compared to their 24-hour mobility exposure is 89.6%, of which 31% of individuals increase their exposure by more than 10% by leaving the home. On average, individuals increased their exposure by 23-44% while commuting and conducting activities out of home (compared to the daily concentration at home), regardless of air quality at their home location. We conclude that our proposed dynamic modelling approach significantly improves the results of traditional methods that rely on a long-term average concentration at the home location and we shed light on the importance of using individual daily trajectories to understand exposure. PMID:26970897

  19. 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

  20. 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

  1. Population Uncertainty in Model Ecosystem: Analysis by Stochastic Differential Equation

    NASA Astrophysics Data System (ADS)

    Morita, Satoru; Tainaka, Kei-ichi; Nagata, Hiroyasu; Yoshimura, Jin

    2008-09-01

    Perturbation experiments are carried out by the numerical simulations of a contact process and its mean-field version. Here, the mortality rate increases or decreases suddenly. It is known that fluctuation enhancement (FE) occurs after perturbation, where FE indicates population uncertainty. In the present paper, we develop a new theory of stochastic differential equation. The agreement between the theory and the mean-field simulation is almost perfect. This theory enables us to find a much stronger FE than that reported previously. We discuss the population uncertainty in the recovering process of endangered species.

  2. Long-term epidemiological studies of atomic bomb survivors in Hiroshima and Nagasaki: study populations, dosimetry and summary of health effects.

    PubMed

    Okubo, Toshiteru

    2012-10-01

    The Radiation Effects Research Foundation succeeded 28 years' worth of activities of the Atomic Bomb Casualty Commission on long-term epidemiological studies in Hiroshima and Nagasaki. It has three major cohorts of atomic bomb survivors, i.e. the Life Span Study (LSS) of 120,000 people, the In Utero Cohort of 3600 and the Second Generation Study (F(1)) of 77,000. The LSS and F(1) studies include a periodic health examination for each sub-cohort, i.e. the Adult Health Study and the F(1) Clinical Study, respectively. An extensive individual dose estimation was conducted and the system was published as the Dosimetry System established in 2002 (DS02). As results of these studies, increases of cancers in relation to dose were clearly shown. Increases of other mortality causes were also observed, including heart and respiratory diseases. There has been no evidence of genetic effects in the survivors' children, including cancer and other multi-factorial diseases. The increase in the expected mortality number in the next 10 y would allow the analyses of further details of the observed effects related to atomic bomb exposures.

  3. Long-term epidemiological studies of atomic bomb survivors in Hiroshima and Nagasaki: study populations, dosimetry and summary of health effects.

    PubMed

    Okubo, Toshiteru

    2012-10-01

    The Radiation Effects Research Foundation succeeded 28 years' worth of activities of the Atomic Bomb Casualty Commission on long-term epidemiological studies in Hiroshima and Nagasaki. It has three major cohorts of atomic bomb survivors, i.e. the Life Span Study (LSS) of 120,000 people, the In Utero Cohort of 3600 and the Second Generation Study (F(1)) of 77,000. The LSS and F(1) studies include a periodic health examination for each sub-cohort, i.e. the Adult Health Study and the F(1) Clinical Study, respectively. An extensive individual dose estimation was conducted and the system was published as the Dosimetry System established in 2002 (DS02). As results of these studies, increases of cancers in relation to dose were clearly shown. Increases of other mortality causes were also observed, including heart and respiratory diseases. There has been no evidence of genetic effects in the survivors' children, including cancer and other multi-factorial diseases. The increase in the expected mortality number in the next 10 y would allow the analyses of further details of the observed effects related to atomic bomb exposures. PMID:22908354

  4. Risk of Acute Kidney Injury and Long-Term Outcome in Patients With Acetaminophen Intoxication: A Nationwide Population-Based Retrospective Cohort Study.

    PubMed

    Chen, Yu-Guang; Lin, Cheng-Li; Dai, Ming-Shen; Chang, Ping-Ying; Chen, Jia-Hong; Huang, Tzu-Chuan; Wu, Yi-Ying; Kao, Chia-Hung

    2015-11-01

    Acetaminophen (APAP) intoxication is a common cause of hepatic toxicity and life-threatening hepatic failure. However, few studies have investigated the possible association between APAP intoxication and acute kidney injury (AKI). We constructed a retrospective cohort study to clarify the relationship between APAP intoxication and the risk of AKI.We identified patients with APAP intoxication and selected a comparison cohort that was 1:4 frequency matched according to age, sex, and year of APAP intoxication diagnosis from the Taiwan National Health Insurance Research Database from 1998 to 2010. We analyzed the risks of AKI for patients with APAP intoxication by using Cox proportional hazards regression models.In this study, 2914 patients with APAP intoxication and 11,656 controls were included. The overall risks of developing AKI were 2.41-fold in the patients with APAP intoxication compared with the comparison cohort. After we excluded APAP intoxication patients with coexisting AKI and hepatic failure/hepatitis, the overall risks of developing AKI were still 2.22-fold in the patients with APAP intoxication. There were 2 patients who had end-stage renal disease (ESRD) following APAP intoxication-related AKI. Limitations include retrospective review, selection bias, and absence of data on detail medications used, laboratory investigations and dosage of APAP intoxication.Our long-term cohort study results showed that AKI is a possible adverse effect among patients with APAP intoxication, regardless of whether patients have presented with hepatic toxicity. However, additional studies are necessary to clarify whether such patients can progress to ESRD. PMID:26579812

  5. Long-term parenteral nutrition

    PubMed Central

    Ladefoged, Karin; Jarnum, Stig

    1978-01-01

    Nineteen patients (11 women and eight men) aged 20-68 received long-term parenteral nutrition, mostly at home, for six to 63 months (mean 19 months). Indications for LTPN were extensive, active Crohn's disease in three patients, intestinocutaneous fistulas in three, and short-bowel syndrome in the remaining 13 patients. Subclavian or intra-atrial (Broviac) catheters were most commonly used, for which the average life was four and seven months respectively. Complications of long-term parenteral nutrition included pneumothorax in four out of 48 subclavian vein punctures. Catheter-induced thrombosis of central veins was shown by phlebography 17 times in nine patients, and eight episodes of total occlusion occurred. Two of these patients had pulmonary infarction. Nineteen episodes of catheter sepsis occurred in 11 patients, but only one was fatal. Complications related to intestinal disease included intra-abdominal abscesses and intestinal fistulas, and disturbances of liver function. Five patients died, though in only two was death related to long-term parenteral nutrition. One of these patients died from catheter sepsis, the other had subdural haematoma possibly caused by anticoagulant treatment. Eight of the 14 surviving patients still needed parenteral nutrition. All received a disability pension, but six had an acceptable quality of life with almost normal social activities. Despite problems such as difficulties in maintaining standardised infusion programmes, it was concluded that long-term parenteral nutrition at home is practicable and consistent with an acceptable quality of life. ImagesFIG 2 PMID:98199

  6. Evolution of gene expression and expression plasticity in long-term experimental populations of Drosophila melanogaster maintained under constant and variable ethanol stress.

    PubMed

    Yampolsky, Lev Y; Glazko, Galina V; Fry, James D

    2012-09-01

    Gene expression responds to the environment and can also evolve rapidly in response to altered selection regimes. Little is known, however, about the extent to which evolutionary adaptation to a particular type of stress involves changes in the within-generation ('plastic') responses of gene expression to the stress. We used microarrays to quantify gene expression plasticity in response to ethanol in laboratory populations of Drosophila melanogaster differing in their history of ethanol exposure. Two populations ('R' populations) were maintained on regular medium, two ('E') were maintained on medium supplemented with ethanol, and two ('M') were maintained in a mixed regime in which half of the population was reared on one medium type, and half on the other, each generation. After more than 300 generations, embryos from each population were collected and exposed to either ethanol or water as a control, and RNA was extracted from the larvae shortly after hatching. Nearly 2000 transcripts showed significant within-generation responses to ethanol exposure. Evolutionary history also affected gene expression: the E and M populations were largely indistinguishable in expression, but differed significantly in expression from the R populations for over 100 transcripts, the majority of which did not show plastic responses. Notably, in no case was the interaction between selection regime and ethanol exposure significant after controlling for multiple comparisons, indicating that adaptation to ethanol in the E and M populations did not involve substantial changes in gene expression plasticity. The results give evidence that expression plasticity evolves considerably more slowly than mean expression.

  7. Long-Term Patterns in the Population Dynamics of Daphnia longispina, Leptodora kindtii and Cyanobacteria in a Shallow Reservoir: A Self-Organising Map (SOM) Approach.

    PubMed

    Wojtal-Frankiewicz, Adrianna; Kruk, Andrzej; Frankiewicz, Piotr; Oleksińska, Zuzanna; Izydorczyk, Katarzyna

    2015-01-01

    The recognition of long-term patterns in the seasonal dynamics of Daphnia longispina, Leptodora kindtii and cyanobacteria is dependent upon their interactions, the water temperature and the hydrological conditions, which were all investigated between 1999 and 2008 in the lowland Sulejow Reservoir. The biomass of cyanobacteria, densities of D. longispina and L. kindtii, concentration of chlorophyll a and water temperature were assessed weekly from April to October at three sampling stations along the longitudinal reservoir axis. The retention time was calculated using data on the actual water inflow and reservoir volume. A self-organising map (SOM) was used due to high interannual variability in the studied parameters and their often non-linear relationships. Classification of the SOM output neurons into three clusters that grouped the sampling terms with similar biotic states allowed identification of the crucial abiotic factors responsible for the seasonal sequence of events: cluster CL-ExSp (extreme/spring) corresponded to hydrologically unstable cold periods (mostly spring) with extreme values and highly variable abiotic factors, which made abiotic control of the biota dominant; cluster CL-StSm (stable/summer) was associated with ordinary late spring and summer and was characterised by stable non-extreme abiotic conditions, which made biotic interactions more important; and the cluster CL-ExSm (extreme/summer), was associated with late spring/summer and characterised by thermal or hydrological extremes, which weakened the role of biotic factors. The significance of the differences between the SOM sub-clusters was verified by Kruskal-Wallis and post-hoc Dunn tests. The importance of the temperature and hydrological regimes as the key plankton-regulating factors in the dam reservoir, as shown by the SOM, was confirmed by the results of canonical correlation analyses (CCA) of each cluster. The demonstrated significance of hydrology in seasonal plankton dynamics

  8. The Long-Term Effects of Organophosphates Poisoning as a Risk Factor of CVDs: A Nationwide Population-Based Cohort Study

    PubMed Central

    Lin, Cheng-Li; Chang, Shih-Yu; Sung, Fung-Chang; Tai, Sally C. W.

    2015-01-01

    Background Organophosphorus pesticides are widely used throughout the world. Because of their ease of availability, organophosphorus compounds are commonly used for self-poisoning in developing countries. The acute effects of exposure to organophosphorus pesticides are well known, but the chronic effects are unclear. Recent studies suggest that abnormalities of the central and peripheral nervous systems persisted for up to 5 years after acute poisoning due to a single large dose of organophosphates (OPs). However, the long-term effects on cardiovascular diseases are poorly understood. Methodology/Principal Findings An OPs-exposed cohort (N = 7,561) and an age- and gender-matched control cohort (N = 30,244), both identified from the National Health Insurance Research Database, were compared. We utilized the multivariable Cox proportional model to estimate the risks of developing arrhythmia, coronary artery disease (CAD) and congestive heart failure (CHF). The patients with acute poisoning from OPs had higher incidence rates of arrhythmia (5.89 vs. 3.61 per 1,000 person-years), CAD (9.10 vs. 6.88 per 1,000 person-years), and CHF (3.89 vs. 2.98 per 1,000 person-years) compared with that of the non-OPs poisoning cohort, with a crude subhazard ratio (SHR) of 1.40, 1.13, and 1.12, respectively. Additionally, a significantly higher risk of arrhythmia was observed in the OPs poisoning cohort (adjusted SHR = 1.25) compared with the non-OPs poisoning cohort, particularly in male patients (adjusted SHR = 1.33) and those under 49 years of age (adjusted SHR = 3.16). After accounting for the competing risks of death, there was a higher risk of arrhythmia and CAD during a three year follow-up period (adjusted SHR = 1.50 for arrhythmia; adjusted SHR = 1.10 for CAD). We also found an adjusted SHR of 1.36 associated with developing CHF after 6 years of follow-up for OPs poisoning cohort. Conclusions Acute OPs poisoning may continuously impact human health through mechanisms that are

  9. Long-Term Patterns in the Population Dynamics of Daphnia longispina, Leptodora kindtii and Cyanobacteria in a Shallow Reservoir: A Self-Organising Map (SOM) Approach

    PubMed Central

    Wojtal-Frankiewicz, Adrianna; Kruk, Andrzej; Frankiewicz, Piotr; Oleksińska, Zuzanna; Izydorczyk, Katarzyna

    2015-01-01

    The recognition of long-term patterns in the seasonal dynamics of Daphnia longispina, Leptodora kindtii and cyanobacteria is dependent upon their interactions, the water temperature and the hydrological conditions, which were all investigated between 1999 and 2008 in the lowland Sulejow Reservoir. The biomass of cyanobacteria, densities of D. longispina and L. kindtii, concentration of chlorophyll a and water temperature were assessed weekly from April to October at three sampling stations along the longitudinal reservoir axis. The retention time was calculated using data on the actual water inflow and reservoir volume. A self-organising map (SOM) was used due to high interannual variability in the studied parameters and their often non-linear relationships. Classification of the SOM output neurons into three clusters that grouped the sampling terms with similar biotic states allowed identification of the crucial abiotic factors responsible for the seasonal sequence of events: cluster CL-ExSp (extreme/spring) corresponded to hydrologically unstable cold periods (mostly spring) with extreme values and highly variable abiotic factors, which made abiotic control of the biota dominant; cluster CL-StSm (stable/summer) was associated with ordinary late spring and summer and was characterised by stable non-extreme abiotic conditions, which made biotic interactions more important; and the cluster CL-ExSm (extreme/summer), was associated with late spring/summer and characterised by thermal or hydrological extremes, which weakened the role of biotic factors. The significance of the differences between the SOM sub-clusters was verified by Kruskal-Wallis and post-hoc Dunn tests. The importance of the temperature and hydrological regimes as the key plankton-regulating factors in the dam reservoir, as shown by the SOM, was confirmed by the results of canonical correlation analyses (CCA) of each cluster. The demonstrated significance of hydrology in seasonal plankton dynamics

  10. Long-Term Patterns in the Population Dynamics of Daphnia longispina, Leptodora kindtii and Cyanobacteria in a Shallow Reservoir: A Self-Organising Map (SOM) Approach.

    PubMed

    Wojtal-Frankiewicz, Adrianna; Kruk, Andrzej; Frankiewicz, Piotr; Oleksińska, Zuzanna; Izydorczyk, Katarzyna

    2015-01-01

    The recognition of long-term patterns in the seasonal dynamics of Daphnia longispina, Leptodora kindtii and cyanobacteria is dependent upon their interactions, the water temperature and the hydrological conditions, which were all investigated between 1999 and 2008 in the lowland Sulejow Reservoir. The biomass of cyanobacteria, densities of D. longispina and L. kindtii, concentration of chlorophyll a and water temperature were assessed weekly from April to October at three sampling stations along the longitudinal reservoir axis. The retention time was calculated using data on the actual water inflow and reservoir volume. A self-organising map (SOM) was used due to high interannual variability in the studied parameters and their often non-linear relationships. Classification of the SOM output neurons into three clusters that grouped the sampling terms with similar biotic states allowed identification of the crucial abiotic factors responsible for the seasonal sequence of events: cluster CL-ExSp (extreme/spring) corresponded to hydrologically unstable cold periods (mostly spring) with extreme values and highly variable abiotic factors, which made abiotic control of the biota dominant; cluster CL-StSm (stable/summer) was associated with ordinary late spring and summer and was characterised by stable non-extreme abiotic conditions, which made biotic interactions more important; and the cluster CL-ExSm (extreme/summer), was associated with late spring/summer and characterised by thermal or hydrological extremes, which weakened the role of biotic factors. The significance of the differences between the SOM sub-clusters was verified by Kruskal-Wallis and post-hoc Dunn tests. The importance of the temperature and hydrological regimes as the key plankton-regulating factors in the dam reservoir, as shown by the SOM, was confirmed by the results of canonical correlation analyses (CCA) of each cluster. The demonstrated significance of hydrology in seasonal plankton dynamics

  11. Long-term data archiving

    SciTech Connect

    Moore, David Steven

    2009-01-01

    Long term data archiving has much value for chemists, not only to retain access to research and product development records, but also to enable new developments and new discoveries. There are some recent regulatory requirements (e.g., FDA 21 CFR Part 11), but good science and good business both benefit regardless. A particular example of the benefits of and need for long term data archiving is the management of data from spectroscopic laboratory instruments. The sheer amount of spectroscopic data is increasing at a scary rate, and the pressures to archive come from the expense to create the data (or recreate it if it is lost) as well as its high information content. The goal of long-term data archiving is to save and organize instrument data files as well as any needed meta data (such as sample ID, LIMS information, operator, date, time, instrument conditions, sample type, excitation details, environmental parameters, etc.). This editorial explores the issues involved in long-term data archiving using the example of Raman spectral databases. There are at present several such databases, including common data format libraries and proprietary libraries. However, such databases and libraries should ultimately satisfy stringent criteria for long term data archiving, including readability for long times into the future, robustness to changes in computer hardware and operating systems, and use of public domain data formats. The latter criterion implies the data format should be platform independent and the tools to create the data format should be easily and publicly obtainable or developable. Several examples of attempts at spectral libraries exist, such as the ASTM ANDI format, and the JCAMP-DX format. On the other hand, proprietary library spectra can be exchanged and manipulated using proprietary tools. As the above examples have deficiencies according to the three long term data archiving criteria, Extensible Markup Language (XML; a product of the World Wide Web

  12. Landscape resistnace to dispersal: Predicting long-term effects of human disturbance on a small and isolated wolf population in southwestern Manitoba, Canada

    EPA Science Inventory

    Landscape fragmentation affects wildlife population viability, in part through the effects it has on individual dispersal. Agricultural development over the past 60 years has resulted in considerable habitat fragmentation in the Riding Mountain National Park (RMNP) region in sou...

  13. A Stochastic Super-Exponential Growth Model for Population Dynamics

    NASA Astrophysics Data System (ADS)

    Avila, P.; Rekker, A.

    2010-11-01

    A super-exponential growth model with environmental noise has been studied analytically. Super-exponential growth rate is a property of dynamical systems exhibiting endogenous nonlinear positive feedback, i.e., of self-reinforcing systems. Environmental noise acts on the growth rate multiplicatively and is assumed to be Gaussian white noise in the Stratonovich interpretation. An analysis of the stochastic super-exponential growth model with derivations of exact analytical formulae for the conditional probability density and the mean value of the population abundance are presented. Interpretations and various applications of the results are discussed.

  14. Radiation risk during long-term spaceflight

    NASA Astrophysics Data System (ADS)

    Petrov, V. M.

    Cosmonauts` exposure to cosmic rays during long-term spaceflight can cause unfavorable effects in health and risk for the crew members` lives. All unfavorable effects induced by exposure should be taken into consideration for the risk estimation. They should include both the acute deterministic effects and delayed effects called stochastic. On the ground the limitation of unfavorable consequences of acute exposure is achieved by means of establishing dose limits. But in space applications this approach can't be acceptable. Establishing a fixed dose limit is adequate to introducing indefinite reserve coefficient and therefore ineffective usage of spacecraft resource. The method of radiation risk calculation caused by acute and delayed effects of cosmonauts' exposure is discussed and substantiated in the report. Peculiarities of the impact of permanent radiation sources (galactic cosmic rays and trapped radiation) and the variable one (solar cosmic rays) are taken into consideration.

  15. Radiation risk during long-term spaceflight.

    PubMed

    Petrov, V M

    2002-01-01

    Cosmonauts' exposure to cosmic rays during long-term spaceflight can cause unfavorable effects in health and risk for the crew members' lives. All unfavorable effects induced by exposure should be taken into consideration for the risk estimation. They should include both the acute deterministic effects and delayed effects called stochastic. On the ground the limitation of unfavorable consequences of acute exposure is achieved by means of establishing dose limits. But in space applications this approach can't be acceptable. Establishing a fixed dose limit is adequate to introducing indefinite reserve coefficient and therefore ineffective usage of spacecraft resource. The method of radiation risk calculation caused by acute and delayed effects of cosmonauts' exposure is discussed and substantiated in the report. Peculiarities of the impact of permanent radiation sources (galactic cosmic rays and trapped radiation) and the variable one (solar cosmic rays) are taken into consideration. PMID:12539775

  16. Long-term trends in naturalized rainbow trout (Oncorhynchus mykiss) populations in the upper Esopus Creek, Ulster County, New York, 2009–15

    USGS Publications Warehouse

    George, Scott D.; Baldigo, Barry P.

    2016-05-13

    The U.S. Geological Survey, in cooperation with Cornell Cooperative Extension of Ulster County, New York State Energy Research and Development Authority, the New York State Department of Environmental Conservation, and the New York City Department of Environmental Protection, surveyed fish communities annually on the main stem and tributaries of the upper Esopus Creek, Ulster County, New York, from 2009 to 2015. This report summarizes the density, biomass, and size structure of rainbow trout (Oncorhynchus mykiss) and brown trout (Salmo trutta) populations from the 2015 surveys along with data from the preceding 6 years. The mean density of rainbow trout populations in 2015 was 98 fish per 0.1 hectare, which was the highest value observed since 2010, and the mean biomass of rainbow trout populations in 2015 was 864 grams per 0.1 hectare, which was the highest value observed since 2012.

  17. Long-Term Health-Related Quality of Life in German Patients with Juvenile Idiopathic Arthritis in Comparison to German General Population

    PubMed Central

    Barth, Swaantje; Haas, Johannes-Peter; Schlichtiger, Jenny; Molz, Johannes; Bisdorff, Betty; Michels, Hartmut; Hügle, Boris; Radon, Katja

    2016-01-01

    Objective Aims of the study were to investigate health-related quality of life (HRQOL) in adult patients with former diagnosis of Juvenile Idiopathic Arthritis (JIA), to compare their HRQOL with the general population and to identify factors related to a poor outcome. Methods In 2012, a cross-sectional survey was performed by mailing a questionnaire to a large cohort of former and current patients of the German Centre for Rheumatology in Children and Adolescents. Only adult patients (≥18 years) with a diagnosis compatible with JIA were included (n = 2592; response 66%). The questionnaire included information about HRQOL (EQ5D), disease-related questions and socio-demographics. Prevalence and 95% confidence intervals (CI) of problems with mobility, self-care, usual activities, pain and anxiety/depression were standardized to the German general population. Factors associated with low HRQOL in JIA patients were identified using logistic regression models. Results Sixty-two percent of the study population was female; age range was 18–73 years. In all dimensions, JIA patients reported statistically significantly more problems than the general population with largest differences in the pain dimension (JIA patients 56%; 95%CI 55–58%; general population 28%; 26–29%) and the anxiety/depression dimension (28%; 27–29% vs. 4%; 4–5%). Lower HRQOL in JIA patients was associated with female sex, older age, lower level of education, still being under rheumatic treatment and disability. Conclusions HRQOL in adult JIA patients is considerably lower than in the general population. As this cohort includes historic patients the new therapeutic schemes available today are expected to improve HRQOL in future. PMID:27115139

  18. Efficacy of a Tailored Tobacco Control Program on Long-Term Use in a Population of U.S. Military Troops

    ERIC Educational Resources Information Center

    Klesges, Robert C.; DeBon, Margaret; Vander Weg, Mark W.; Haddock, C. Keith; Lando, Harry A.; Relyea, George E.; Peterson, Alan L.; Talcott, G. Wayne

    2006-01-01

    The authors evaluated the effect of a brief tailored smoking control intervention delivered during basic military training on tobacco use in a population of military personnel (N = 33,215). Participants were randomized to either a tobacco use intervention (smoking cessation, smokeless tobacco use cessation, or prevention depending on tobacco…

  19. Allelic Richness following Population Founding Events – A Stochastic Modeling Framework Incorporating Gene Flow and Genetic Drift

    PubMed Central

    Greenbaum, Gili; Templeton, Alan R.; Zarmi, Yair; Bar-David, Shirli

    2014-01-01

    Allelic richness (number of alleles) is a measure of genetic diversity indicative of a population's long-term potential for adaptability and persistence. It is used less commonly than heterozygosity as a genetic diversity measure, partially because it is more mathematically difficult to take into account the stochastic process of genetic drift for allelic richness. This paper presents a stochastic model for the allelic richness of a newly founded population experiencing genetic drift and gene flow. The model follows the dynamics of alleles lost during the founder event and simulates the effect of gene flow on maintenance and recovery of allelic richness. The probability of an allele's presence in the population was identified as the relevant statistical property for a meaningful interpretation of allelic richness. A method is discussed that combines the probability of allele presence with a population's allele frequency spectrum to provide predictions for allele recovery. The model's analysis provides insights into the dynamics of allelic richness following a founder event, taking into account gene flow and the allele frequency spectrum. Furthermore, the model indicates that the “One Migrant per Generation” rule, a commonly used conservation guideline related to heterozygosity, may be inadequate for addressing preservation of diversity at the allelic level. This highlights the importance of distinguishing between heterozygosity and allelic richness as measures of genetic diversity, since focusing merely on the preservation of heterozygosity might not be enough to adequately preserve allelic richness, which is crucial for species persistence and evolution. PMID:25526062

  20. Allelic richness following population founding events--a stochastic modeling framework incorporating gene flow and genetic drift.

    PubMed

    Greenbaum, Gili; Templeton, Alan R; Zarmi, Yair; Bar-David, Shirli

    2014-01-01

    Allelic richness (number of alleles) is a measure of genetic diversity indicative of a population's long-term potential for adaptability and persistence. It is used less commonly than heterozygosity as a genetic diversity measure, partially because it is more mathematically difficult to take into account the stochastic process of genetic drift for allelic richness. This paper presents a stochastic model for the allelic richness of a newly founded population experiencing genetic drift and gene flow. The model follows the dynamics of alleles lost during the founder event and simulates the effect of gene flow on maintenance and recovery of allelic richness. The probability of an allele's presence in the population was identified as the relevant statistical property for a meaningful interpretation of allelic richness. A method is discussed that combines the probability of allele presence with a population's allele frequency spectrum to provide predictions for allele recovery. The model's analysis provides insights into the dynamics of allelic richness following a founder event, taking into account gene flow and the allele frequency spectrum. Furthermore, the model indicates that the "One Migrant per Generation" rule, a commonly used conservation guideline related to heterozygosity, may be inadequate for addressing preservation of diversity at the allelic level. This highlights the importance of distinguishing between heterozygosity and allelic richness as measures of genetic diversity, since focusing merely on the preservation of heterozygosity might not be enough to adequately preserve allelic richness, which is crucial for species persistence and evolution.

  1. How domain growth is implemented determines the long-term behavior of a cell population through its effect on spatial correlations

    NASA Astrophysics Data System (ADS)

    Ross, Robert J. H.; Baker, R. E.; Yates, C. A.

    2016-07-01

    Domain growth plays an important role in many biological systems, and so the inclusion of domain growth in models of these biological systems is important to understanding how these systems function. In this work we present methods to include the effects of domain growth on the evolution of spatial correlations in a continuum approximation of a lattice-based model of cell motility and proliferation. We show that, depending on the way in which domain growth is implemented, different steady-state densities are predicted for an agent population. Furthermore, we demonstrate that the way in which domain growth is implemented can result in the evolution of the agent density depending on the size of the domain. Continuum approximations that ignore spatial correlations cannot capture these behaviors, while those that account for spatial correlations do. These results will be of interest to researchers in developmental biology, as they suggest that the nature of domain growth can determine the characteristics of cell populations.

  2. Impact of External Beam Adjuvant Radiotherapy on Health-Related Quality of Life for Long-Term Survivors of Endometrial Adenocarcinoma: A Population-Based Study

    SciTech Connect

    Poll-Franse, Lonneke V. van de; Essink-Bot, Marie-Louise; Vingerhoets, Ad J.J.M.; Lybeert, Marnix L.M.; Berg, Hetty A. van den; Coebergh, Jan Willem W.

    2007-09-01

    Purpose: To compare the health-related quality of life (HRQOL) among 5-10-year survivors of Stage I-II endometrial (adeno-)carcinoma (EC) treated with surgery alone or surgery with external beam adjuvant radiotherapy (EBRT) and an age-matched norm population. Methods and Materials: A population-based, cross-sectional survey was conducted by the Eindhoven Cancer Registry. All patients were included who had been diagnosed with EC between 1994 and 1998 (n = 462). Information from the questionnaires returned was linked to data from the Eindhoven Cancer Registry on patient, tumor, and treatment characteristics. Results: Responses were received from 75% of the patients. The analyses were restricted to women with Stage I-II disease at diagnosis, treated with either surgery alone or surgery with adjuvant EBRT, and without recurrent disease or new primary malignancies (n = 264). The patients who had received adjuvant EBRT (n = 80) had had a significantly higher tumor stage and grade at diagnosis (p < 0.0001) and a longer mean time since diagnosis (p = 0.04). Age, number of comorbid diseases, current marital status, nulliparity, education, and occupation were similar for both treatment groups. On multivariate analyses, adjuvant EBRT was independently and negatively associated with the vitality and physical and social well-being scale scores. The HRQOL scores of both treatment groups, however, were similar to those of an age-matched norm population. Conclusion: In general, the HRQOL of EC survivors is good. EC survivors treated with surgery alone had a better HRQOL than women treated with surgery and adjuvant EBRT, although for both groups, the HRQOL was in the range of the norm population.

  3. Long-term decline of the populations of Fucales (Cystoseira spp. and Sargassum spp.) in the Albères coast (France, North-western Mediterranean).

    PubMed

    Thibaut, Thierry; Pinedo, Susana; Torras, Xavier; Ballesteros, Enric

    2005-12-01

    Only five of fourteen species of Fucales reported at the end of the XIXth century are currently present in the Albères Coast (France, NW Mediterranean). According to historical data there has been a steady decrease of all the populations since the 1940s. Seven taxa now extinct (Cystoseira crinita, Cystoseira barbata, Cystoseira foeniculacea f. tenuiramosa, Cystoseira spinosa, Cystoseira spinosa var. compressa, Sargassum hornschuchii and Sargassum vulgare) were considered frequent and some of them were the dominant and engineering species in several phytobenthic assemblages. Moreover, only one of the five species left, shows no signs of regression (Cystoseira compressa), two are considered as rare (Cystoseira caespitosa, Cystoseira zosteroides), and one is very rare (Cystoseira elegans). Cystoseira mediterranea, a species that was reported to make a continuous belt along the shores of the Albères coast, has almost disappeared from some areas. Overgrazing by sea urchins, outcompetition by mussels, habitat destruction, scientific research sampling and, probably, human trampling and chemical pollution are to be blamed for the decline of populations thriving in shallow waters. Deep-water species have been affected by an increase in water turbidity and, probably, chemical pollution and direct plant destruction attributed to net fishing. If degradation of the environmental conditions continues, the remaining Cystoseira species will face a most unwelcome prospect. Even after the removal of the causes that led to its die-off, natural restoration of extinct species seems not to be possible because the decline has also affected populations from nearby areas and zygotes are unable to disperse over long distances. Urgent management actions have to be designed in order to improve the current situation of the populations of Fucales in the Albères coast.

  4. Long-term decline of the populations of Fucales (Cystoseira spp. and Sargassum spp.) in the Albères coast (France, North-western Mediterranean).

    PubMed

    Thibaut, Thierry; Pinedo, Susana; Torras, Xavier; Ballesteros, Enric

    2005-12-01

    Only five of fourteen species of Fucales reported at the end of the XIXth century are currently present in the Albères Coast (France, NW Mediterranean). According to historical data there has been a steady decrease of all the populations since the 1940s. Seven taxa now extinct (Cystoseira crinita, Cystoseira barbata, Cystoseira foeniculacea f. tenuiramosa, Cystoseira spinosa, Cystoseira spinosa var. compressa, Sargassum hornschuchii and Sargassum vulgare) were considered frequent and some of them were the dominant and engineering species in several phytobenthic assemblages. Moreover, only one of the five species left, shows no signs of regression (Cystoseira compressa), two are considered as rare (Cystoseira caespitosa, Cystoseira zosteroides), and one is very rare (Cystoseira elegans). Cystoseira mediterranea, a species that was reported to make a continuous belt along the shores of the Albères coast, has almost disappeared from some areas. Overgrazing by sea urchins, outcompetition by mussels, habitat destruction, scientific research sampling and, probably, human trampling and chemical pollution are to be blamed for the decline of populations thriving in shallow waters. Deep-water species have been affected by an increase in water turbidity and, probably, chemical pollution and direct plant destruction attributed to net fishing. If degradation of the environmental conditions continues, the remaining Cystoseira species will face a most unwelcome prospect. Even after the removal of the causes that led to its die-off, natural restoration of extinct species seems not to be possible because the decline has also affected populations from nearby areas and zygotes are unable to disperse over long distances. Urgent management actions have to be designed in order to improve the current situation of the populations of Fucales in the Albères coast. PMID:16026805

  5. Long-term monitoring of reef corals at the Flower Garden Banks (northwest Gulf of Mexico): Reef coral population changes and historical incorporation of barium in Montastrea annularis

    SciTech Connect

    Deslarzes, K.J.P.

    1992-01-01

    Reef coral populations were monitored from 1988 to 1991 at the Flower Garden Banks located in the northwestern Gulf of Mexico. The status of reef coral populations, and natural or man-made factors potentially affecting their well-being were determined. Man-made chronic disturbances are degrading coral reef resources on a global scale. Yet, the Flower Garden coral reefs seem to have been sheltered from the effects of regional stresses generated by population growth and increased industrial activity. Since 1974, reef coral population levels have remained unchanged in the Montastrea-Diploria Zones at the Flower Garden Banks. Live coral cover ranges between 46 and 46.5%. Montastrea annularis and Diploria strigosa comprise 80% of the coral cover on either bank. The remainder of the cover is mostly shared by eight other taxa. Coral taxa appear to be more homogeneously distributed on the West Bank. The relatively greater number of Agaricia spp., Madracis decastis, and P. astreoides colonies on the East Bank may be the source of a decreased evenness. The health of reef corals was assessed using repetitive and non-repetitive photographic methods, and accretionary growth measurements of M. annularis. Reef corals have undergone small scale changes at the Flower Gardens probably reflecting natural disturbance, predation, disease, and inter-specific competition. White mat disease (ridge disease) is shown to generate more tissue loss than any of the three bleaching events that took place at the Flower Gardens (1989, 1990, and 1991). Advance to retreat linear ratios of encrusting growth revealed a net tissue gain on the East Bank and a net tissue loss on the West Bank. Growth rates of M. annularis were highly variable. The annual barium content from 1910 in 1989 in a M. annularis colony from the West Flower Garden did not reveal trends associated with the extensive oil and gas exploration in the northern Gulf of Mexico.

  6. Interventions promoting physical activity among obese populations: a meta-analysis considering global effect, long-term maintenance, physical activity indicators and dose characteristics.

    PubMed

    Gourlan, M J; Trouilloud, D O; Sarrazin, P G

    2011-07-01

    As the benefits that regular physical activity (PA) have on obesity are well known, many interventions promote active lifestyle adoption among obese populations. This meta-analysis aims to determine (i) the global effect that interventions promoting PA among obese populations have on their PA behaviour; (ii) variations in the effect of interventions depending on the PA indicator used; (iii) the programme's dose characteristics and (iv) maintenance of the intervention effects after the intervention has ended. A comprehensive search through databases and review articles was completed. Forty-six studies met the inclusion criteria. Calculations of effect size (Cohen's d) and a moderator analysis were conducted. The meta-analysis showed that interventions globally have an impact on the PA behaviour of obese populations (d = 0.44; 95% CI = 0.31, 0.57). The moderator analysis revealed that interventions of less than 6 months reported significantly larger effects than longer interventions. Moreover, the interventions had a stronger impact on the number of steps and the PA indexes (i.e. composite scores reflecting PA practice) than on other PA indicators. Finally, the analysis revealed that interventions succeed in maintaining PA behaviour after the intervention is over. However, relatively few studies addressed this issue (n = 9). Despite global positive effects, further research is needed to determine the optimal dose for interventions and to evaluate the maintenance of intervention effects.

  7. NT-proBNP Predicts Cardiovascular Death in the General Population Independent of Left Ventricular Mass and Function: Insights from a Large Population-Based Study with Long-Term Follow-Up

    PubMed Central

    Dietl, Alexander; Stark, Klaus; Zimmermann, Martina E.; Meisinger, Christa; Schunkert, Heribert; Birner, Christoph; Maier, Lars S.; Peters, Annette

    2016-01-01

    Aims B-type natriuretic peptide (BNP) and N-terminal proBNP (NT-proBNP) predict cardiovascular endpoints in patients and all-cause death in the general population. This was assigned to their association with clinical cardiac remodelling defined as changes in size, shape and function of the heart. The aim of this study was to evaluate whether NT-proBNP and BNP were associated with cardiovascular and overall death independent of clinical cardiac remodelling measured by echocardiography as left ventricular hypertrophy (LVH), diastolic dysfunction and left ventricular ejection fraction (EF). Methods and Results In a general population-based cohort study from Germany (KORA-S3) with subjects’ baseline age ranging from 25 to 74 years, cardiac morphology and function were assessed as left ventricular mass (LVM), diastolic dysfunction and EF by echocardiography and circulating NT-proBNP and BNP were measured at baseline. In 1,223 subjects with mortality follow-up information, we examined the association of baseline NT-proBNP and BNP with cardiovascular mortality (number of deaths = 52, median follow-up time = 12.9years) using Cox regression without and with adjustment for cardiovascular risk factors, LVM, diastolic dysfunction and EF. The risk of cardiovascular mortality increased with higher NT-proBNP levels measured at baseline (hazard ratio HR = 1.67 per unit increment in logNT-proBNP, p = 2.78*10−4, adjusted for age and sex). This increased risk persisted after adjustment for cardiovascular risk factors, LVM, diastolic dysfunction and EF (HR = 1.73; p = 0.047). When excluding subjects with relevant LVH (LVM to body surface area > 149g/m2 in men / 122g/m2 in women), the NT-proBNP association with mortality was still significant (n = 1,138; number of deaths = 35; HR = 1.48; p = 0.04). We found similar results for BNP. Conclusion Our data confirms NT-proBNP and BNP as predictor of cardiovascular mortality in a large general population-based study with long-term follow

  8. A stochastic population model of mid-continental mallards

    USGS Publications Warehouse

    Koford, Rolf R.; Sauer, J.R.; Johnson, D.H.; Nichols, J.D.; Samuel, M.D.; McCullough, D.R.; Barrett, R.H.

    1992-01-01

    We developed a simulation model that integrates infonnation on factors affecting the population dynamics of mallards in the mid-continental region of the United States. In the model we vary age, body mass, and reproductive and molt status of simulated females. Females use several types of nesting and foraging habitat in 15 geographic areas. Deterministic and stochastic events cause mortality or attribute changes on a daily basis, depending on current attributes, habitat, area, calendar date, wetland conditions, temperature, and various mortality agents. Because the model encompasses the entire year, it can be used to examine cross-seasonal effects. A simulated increase in nest success from 0.14 to 0.17 changed the annual rate of population growth from -6% to -1 %. A simulated 75% reduction in lead poisoning changed the rate from -6% to -3%.

  9. Volunteer Conservation Action Data Reveals Large-Scale and Long-Term Negative Population Trends of a Widespread Amphibian, the Common Toad (Bufo bufo)

    PubMed Central

    Petrovan, Silviu O.

    2016-01-01

    Rare and threatened species are the most frequent focus of conservation science and action. With the ongoing shift from single-species conservation towards the preservation of ecosystem services, there is a greater need to understand abundance trends of common species because declines in common species can disproportionately impact ecosystems function. We used volunteer-collected data in two European countries, the United Kingdom (UK) and Switzerland, since the 1970s to assess national and regional trends for one of Europe’s most abundant amphibian species, the common toad (Bufo bufo). Millions of toads were moved by volunteers across roads during this period in an effort to protect them from road traffic. For Switzerland, we additionally estimated trends for the common frog (Rana temporaria), a similarly widespread and common amphibian species. We used state-space models to account for variability in detection and effort and included only populations with at least 5 years of data; 153 populations for the UK and 141 for Switzerland. Common toads declined continuously in each decade in both countries since the 1980s. Given the declines, this common species almost qualifies for International Union for the Conservation of Nature (IUCN) red-listing over this period despite volunteer conservation efforts. Reasons for the declines and wider impacts remain unknown. By contrast, common frog populations were stable or increasing in Switzerland, although there was evidence of declines after 2003. “Toads on Roads” schemes are vital citizen conservation action projects, and the data from such projects can be used for large scale trend estimations of widespread amphibians. We highlight the need for increased research into the status of common amphibian species in addition to conservation efforts focusing on rare and threatened species. PMID:27706154

  10. The Effects of Both Recent and Long-Term Selection and Genetic Drift Are Readily Evident in North American Barley Breeding Populations.

    PubMed

    Poets, Ana M; Mohammadi, Mohsen; Seth, Kiran; Wang, Hongyun; Kono, Thomas J Y; Fang, Zhou; Muehlbauer, Gary J; Smith, Kevin P; Morrell, Peter L

    2015-12-29

    Barley was introduced to North America ∼400 yr ago but adaptation to modern production environments is more recent. Comparisons of allele frequencies among growth habits and spike (inflorescence) types in North America indicate that significant genetic differentiation has accumulated in a relatively short evolutionary time span. Allele frequency differentiation is greatest among barley with two-row vs. six-row spikes, followed by spring vs. winter growth habit. Large changes in allele frequency among breeding programs suggest a major contribution of genetic drift and linked selection on genetic variation. Despite this, comparisons of 3613 modern North American cultivated barley breeding lines that differ for spike-type and growth habit permit the discovery of 142 single nucleotide polymorphism (SNP) outliers putatively linked to targets of selection. For example, SNPs within the Cbf4, Ppd-H1, and Vrn-H1 loci, which have previously been associated with agronomically adaptive phenotypes, are identified as outliers. Analysis of extended haplotype sharing identifies genomic regions shared within and among breeding populations, suggestive of a number of genomic regions subject to recent selection. Finally, we are able to identify recent bouts of gene flow between breeding populations that could point to the sharing of agronomically adaptive variation. These results are supported by pedigrees and breeders' understanding of germplasm sharing.

  11. How domain growth is implemented determines the long-term behavior of a cell population through its effect on spatial correlations.

    PubMed

    Ross, Robert J H; Baker, R E; Yates, C A

    2016-07-01

    Domain growth plays an important role in many biological systems, and so the inclusion of domain growth in models of these biological systems is important to understanding how these systems function. In this work we present methods to include the effects of domain growth on the evolution of spatial correlations in a continuum approximation of a lattice-based model of cell motility and proliferation. We show that, depending on the way in which domain growth is implemented, different steady-state densities are predicted for an agent population. Furthermore, we demonstrate that the way in which domain growth is implemented can result in the evolution of the agent density depending on the size of the domain. Continuum approximations that ignore spatial correlations cannot capture these behaviors, while those that account for spatial correlations do. These results will be of interest to researchers in developmental biology, as they suggest that the nature of domain growth can determine the characteristics of cell populations. PMID:27575165

  12. Consequences of digital mammography in population-based breast cancer screening: initial changes and long-term impact on referral rates

    PubMed Central

    Karssemeijer, Nico; Beijerinck, David; Deurenberg, Jan J. M.; van Engen, Ruben E.; Broeders, Mireille J. M.; den Heeten, Gerard J.

    2010-01-01

    Objectives: To investigate the referral pattern after the transition to full-field digital mammography (FFDM) in a population-based breast cancer screening programme. Methods: Preceding the nationwide digitalisation of the Dutch screening programme, an FFDM feasibility study was conducted. Detection and referral rates for FFDM and screen-film mammography (SFM) were compared for first and subsequent screens. Furthermore, radiological characteristics of referrals in digital screening were assessed. Results: A total of 312,414 screening mammograms were performed (43,913 digital and 268,501 conventional), with 4,473 consecutive referrals (966 following FFDM). Initially the FFDM referral rate peaked, and many false-positive results were noted as a consequence of pseudolesions and increased detection of (benign) microcalcifications. A higher overall referral rate was observed in FFDM screening in both first and subsequent examinations (p < .001), with a significant increase in cancer detection (p = .010). Conclusion: As a result of initial inexperience with digital screening images implementing FFDM in a population-based breast cancer screening programme may lead to a strong, but temporary increase in referral. Dedicated training in digital screening for radiographers and screening radiologists is therefore recommended. Referral rates decrease and stabilise (learning curve effect) at a higher level than in conventional screening, yet with significantly enhanced cancer detection. PMID:20407901

  13. The Effects of Both Recent and Long-Term Selection and Genetic Drift Are Readily Evident in North American Barley Breeding Populations

    PubMed Central

    Poets, Ana M.; Mohammadi, Mohsen; Seth, Kiran; Wang, Hongyun; Kono, Thomas J. Y.; Fang, Zhou; Muehlbauer, Gary J.; Smith, Kevin P.; Morrell, Peter L.

    2015-01-01

    Barley was introduced to North America ∼400 yr ago but adaptation to modern production environments is more recent. Comparisons of allele frequencies among growth habits and spike (inflorescence) types in North America indicate that significant genetic differentiation has accumulated in a relatively short evolutionary time span. Allele frequency differentiation is greatest among barley with two-row vs. six-row spikes, followed by spring vs. winter growth habit. Large changes in allele frequency among breeding programs suggest a major contribution of genetic drift and linked selection on genetic variation. Despite this, comparisons of 3613 modern North American cultivated barley breeding lines that differ for spike-type and growth habit permit the discovery of 142 single nucleotide polymorphism (SNP) outliers putatively linked to targets of selection. For example, SNPs within the Cbf4, Ppd-H1, and Vrn-H1 loci, which have previously been associated with agronomically adaptive phenotypes, are identified as outliers. Analysis of extended haplotype sharing identifies genomic regions shared within and among breeding populations, suggestive of a number of genomic regions subject to recent selection. Finally, we are able to identify recent bouts of gene flow between breeding populations that could point to the sharing of agronomically adaptive variation. These results are supported by pedigrees and breeders’ understanding of germplasm sharing. PMID:26715093

  14. [Long-term survival after severe trauma].

    PubMed

    Mutschler, W; Mutschler, M; Graw, M; Lefering, R

    2016-07-01

    Long-term survival after severe trauma is rarely addressed in German trauma journals although knowledge of life expectancy and identification of factors contributing to increased mortality are important for lifetime care management, development of service models, and targeting health promotion and prevention interventions. As reliable data in Germany are lacking, we compiled data mainly from the USA and Australia to describe life expectancy, risk factors, and predictors of outcome in patients experiencing traumatic spinal cord injury, traumatic brain injury, and polytrauma. Two years after trauma, life expectancy in all three categories was significantly lower than that of the general population. It depends strongly on severity of disability, age, and gender and is quantifiable. Whereas improvements in medical care have led to a marked decline in short-term mortality, surprisingly long-term survival in severe trauma has not changed over the past 30 years. Therefore, there is need to intensify long-term trauma patient care and to find new strategies to limit primary damage. PMID:27342106

  15. [Autoimmune processes after long-term low-level exposure to electromagnetic fields (the results of an experiment). Part 1. Mobile communications and changes in electromagnetic conditions for the population. Needs for additional substantiation of the existing hygienic standards].

    PubMed

    Grigor'ev, Iu G; Grigor'ev, O A; Ivanov, A A; Liaginskaia, A M; Merkulov, A V; Stepanov, V S; Shagina, N B

    2010-01-01

    Mobile communications provides a new source of electromagnetic exposure for almost the whole population of the Russian Federation. For the first time in the history of civilization the brain of mobile phone users was exposed to localized radiofrequency (RF) electromagnetic fields (EMF). Population exposure from the base stations is also considered to be specific. However, existing standards for limiting the exposure do not account for this special EMF source and may not ensure the absence of health effects. There was a need for reliable information that would extend databases used for development of new standards. As recommended by the World Health Organization an additional experiment was performed under the supervision of foreign experts, which showed changes in autoimmune status in rats after long-term low-level RF EMF exposure with an incident power density of 500 microW/cm2.

  16. Development of autoimmune disease in SCID mice populated with long-term "in vitro" proliferating (NZB x NZW)F1 pre-B cells

    PubMed Central

    1992-01-01

    Pre-B cell lines proliferating for several months on stromal cells in the presence of interleukin 7 (IL-7) were established from fetal liver of (NZB x NZW)F1 mice. They express the B lineage-specific markers PB76, B220, and VpreB, but do not express surface immunoglobulin (sIg). Upon removal of IL-7 from the culture, they differentiate to sIg+ B cells that can then be stimulated by lipopolysaccharide to become IgM- secreting cells. Transfer of these pre-B cell lines into SCID mice leads to hypergammaglobulinemia of IgM (600-900 micrograms/ml), IgG2a (1-3 mg/ml), and IgG3 (300-500 micrograms/ml) for the next 3-5 mo. The spleen appears populated with (NZB x NZW)F1-derived pre-B cells, few B cells, and many IgM and/or IgG-producing plasma cells. In contrast, SCID mice populated with pre-B cell lines of normal (C57BL/6 x DBA/2)F1 mouse fetal liver develop normal levels of serum IgM (approximately 100- 300 micrograms/ml), almost no detectable levels of IgG, and no plasma cell hyperplasia. The (NZB x NZW)F1 pre-B cell-populated SCID mice contain elevated serum titers of IgG antinuclear autoantibodies, but no retroviral gp70-specific nor erythrocyte-specific autoantibodies. Up to 20% of the SCID mice develop proteinuria as a consequence of IgG deposits in the kidney glomeruli during a 7-mo period of observation. All signs of autoimmune disease seen in these mice are independent of the sex of the SCID host. This experimental system provides a distinction between the disease-determining (NZB x NZW)F1 genes, which are expressed in the B lymphocyte lineage and cause the development of the disease, from those expressed in other cell lineages which only modulate its progression. PMID:1402680

  17. Long term cause specific mortality among 34 489 five year survivors of childhood cancer in Great Britain: population based cohort study

    PubMed Central

    Fidler, Miranda M; Reulen, Raoul C; Winter, David L; Kelly, Julie; Jenkinson, Helen C; Skinner, Rod; Frobisher, Clare

    2016-01-01

    Objective To determine whether modern treatments for cancer are associated with a net increased or decreased risk of death from neoplastic and non-neoplastic causes among survivors of childhood cancer. Design Population based cohort study. Setting British Childhood Cancer Survivor Study. Participants Nationwide population based cohort of 34 489 five year survivors of childhood cancer with a diagnosis from 1940 to 2006 and followed up until 28 February 2014. Main outcome measures Cause specific standardised mortality ratios and absolute excess risks are reported. Multivariable Poisson regression models were utilised to evaluate the simultaneous effect of risk factors. Likelihood ratio tests were used to test for heterogeneity or trend. Results Overall, 4475 deaths were observed, which was 9.1 (95% confidence interval 8.9 to 9.4) times that expected in the general population, corresponding to 64.2 (95% confidence interval 62.1 to 66.3) excess deaths per 10 000 person years. The number of excess deaths from all causes declined among those treated more recently; those treated during 1990-2006 experienced 30% of the excess number of deaths experienced by those treated before 1970. The corresponding percentages for the decline in excess deaths from recurrence or progression and non-neoplastic causes were 30% and 60%, respectively. Among survivors aged 50-59 years, 41% and 22% of excess deaths were attributable to subsequent primary neoplasms and circulatory conditions, respectively, whereas the corresponding percentages among those aged 60 years or more were 31% and 37%. Conclusions The net effects of changes in cancer treatments, and surveillance and management for late effects, over the period 1940 to 2006 was to reduce the excess number of deaths from both recurrence or progression and non-neoplastic causes among those treated more recently. Among survivors aged 60 years or more, the excess number of deaths from circulatory causes exceeds the excess number

  18. Towards a landscape scale management of pesticides: ERA using changes in modelled occupancy and abundance to assess long-term population impacts of pesticides.

    PubMed

    Topping, Chris J; Craig, Peter S; de Jong, Frank; Klein, Michael; Laskowski, Ryszard; Manachini, Barbara; Pieper, Silvia; Smith, Rob; Sousa, José Paulo; Streissl, Franz; Swarowsky, Klaus; Tiktak, Aaldrik; van der Linden, Ton

    2015-12-15

    Pesticides are regulated in Europe and this process includes an environmental risk assessment (ERA) for non-target arthropods (NTA). Traditionally a non-spatial or field trial assessment is used. In this study we exemplify the introduction of a spatial context to the ERA as well as suggest a way in which the results of complex models, necessary for proper inclusion of spatial aspects in the ERA, can be presented and evaluated easily using abundance and occupancy ratios (AOR). We used an agent-based simulation system and an existing model for a widespread carabid beetle (Bembidion lampros), to evaluate the impact of a fictitious highly-toxic pesticide on population density and the distribution of beetles in time and space. Landscape structure and field margin management were evaluated by comparing scenario-based ERAs for the beetle. Source-sink dynamics led to an off-crop impact even when no pesticide was present off-crop. In addition, the impacts increased with multi-year application of the pesticide whereas current ERA considers only maximally one year. These results further indicated a complex interaction between landscape structure and pesticide effect in time, both in-crop and off-crop, indicating the need for NTA ERA to be conducted at landscape- and multi-season temporal-scales. Use of AOR indices to compare ERA outputs facilitated easy comparison of scenarios, allowing simultaneous evaluation of impacts and planning of mitigation measures. The landscape and population ERA approach also demonstrates that there is a potential to change from regulation of a pesticide in isolation, towards the consideration of pesticide management at landscape scales and provision of biodiversity benefits via inclusion and testing of mitigation measures in authorisation procedures.

  19. Towards a landscape scale management of pesticides: ERA using changes in modelled occupancy and abundance to assess long-term population impacts of pesticides.

    PubMed

    Topping, Chris J; Craig, Peter S; de Jong, Frank; Klein, Michael; Laskowski, Ryszard; Manachini, Barbara; Pieper, Silvia; Smith, Rob; Sousa, José Paulo; Streissl, Franz; Swarowsky, Klaus; Tiktak, Aaldrik; van der Linden, Ton

    2015-12-15

    Pesticides are regulated in Europe and this process includes an environmental risk assessment (ERA) for non-target arthropods (NTA). Traditionally a non-spatial or field trial assessment is used. In this study we exemplify the introduction of a spatial context to the ERA as well as suggest a way in which the results of complex models, necessary for proper inclusion of spatial aspects in the ERA, can be presented and evaluated easily using abundance and occupancy ratios (AOR). We used an agent-based simulation system and an existing model for a widespread carabid beetle (Bembidion lampros), to evaluate the impact of a fictitious highly-toxic pesticide on population density and the distribution of beetles in time and space. Landscape structure and field margin management were evaluated by comparing scenario-based ERAs for the beetle. Source-sink dynamics led to an off-crop impact even when no pesticide was present off-crop. In addition, the impacts increased with multi-year application of the pesticide whereas current ERA considers only maximally one year. These results further indicated a complex interaction between landscape structure and pesticide effect in time, both in-crop and off-crop, indicating the need for NTA ERA to be conducted at landscape- and multi-season temporal-scales. Use of AOR indices to compare ERA outputs facilitated easy comparison of scenarios, allowing simultaneous evaluation of impacts and planning of mitigation measures. The landscape and population ERA approach also demonstrates that there is a potential to change from regulation of a pesticide in isolation, towards the consideration of pesticide management at landscape scales and provision of biodiversity benefits via inclusion and testing of mitigation measures in authorisation procedures. PMID:26318547

  20. Long-term course of opioid addiction.

    PubMed

    Hser, Yih-Ing; Evans, Elizabeth; Grella, Christine; Ling, Walter; Anglin, Douglas

    2015-01-01

    Opioid addiction is associated with excess mortality, morbidities, and other adverse conditions. Guided by a life-course framework, we review the literature on the long-term course of opioid addiction in terms of use trajectories, transitions, and turning points, as well as other factors that facilitate recovery from addiction. Most long-term follow-up studies are based on heroin addicts recruited from treatment settings (mostly methadone maintenance treatment), many of whom are referred by the criminal justice system. Cumulative evidence indicates that opioid addiction is a chronic disorder with frequent relapses. Longer treatment retention is associated with a greater likelihood of abstinence, whereas incarceration is negatively related to subsequent abstinence. Over the long term, the mortality rate of opioid addicts (overdose being the most common cause) is about 6 to 20 times greater than that of the general population; among those who remain alive, the prevalence of stable abstinence from opioid use is low (less than 30% after 10-30 years of observation), and many continue to use alcohol and other drugs after ceasing to use opioids. Histories of sexual or physical abuse and comorbid mental disorders are associated with the persistence of opioid use, whereas family and social support, as well as employment, facilitates recovery. Maintaining opioid abstinence for at least five years substantially increases the likelihood of future stable abstinence. Recent advances in pharmacological treatment options (buprenorphine and naltrexone) include depot formulations offering longer duration of medication; their impact on the long-term course of opioid addiction remains to be assessed.

  1. Sea Star Wasting Disease in the Keystone Predator Pisaster ochraceus in Oregon: Insights into Differential Population Impacts, Recovery, Predation Rate, and Temperature Effects from Long-Term Research

    PubMed Central

    Menge, Bruce A.; Cerny-Chipman, Elizabeth B.; Johnson, Angela; Sullivan, Jenna; Gravem, Sarah; Chan, Francis

    2016-01-01

    Sea star wasting disease (SSWD) first appeared in Oregon in April 2014, and by June had spread to most of the coast. Although delayed compared to areas to the north and south, SSWD was initially most intense in north and central Oregon and spread southward. Up to 90% of individuals showed signs of disease from June-August 2014. In rocky intertidal habitats, populations of the dominant sea star Pisaster ochraceus were rapidly depleted, with magnitudes of decline in density among sites ranging from -2x to -9x (59 to 84%) and of biomass from -2.6x to -15.8x (60 to 90%) by September 2014. The frequency of symptomatic individuals declined over winter and persisted at a low rate through the spring and summer 2015 (~5–15%, at most sites) and into fall 2015. Disease expression included six symptoms: initially with twisting arms, then deflation and/or lesions, lost arms, losing grip on substrate, and final disintegration. SSWD was disproportionally higher in orange individuals, and higher in tidepools. Although historically P. ochraceus recruitment has been low, from fall 2014 to spring 2015 an unprecedented surge of sea star recruitment occurred at all sites, ranging from ~7x to 300x greater than in 2014. The loss of adult and juvenile individuals in 2014 led to a dramatic decline in predation rate on mussels compared to the previous two decades. A proximate cause of wasting was likely the “Sea Star associated Densovirus” (SSaDV), but the ultimate factors triggering the epidemic, if any, remain unclear. Although warm temperature has been proposed as a possible trigger, SSWD in Oregon populations increased with cool temperatures. Since P. ochraceus is a keystone predator that can strongly influence the biodiversity and community structure of the intertidal community, major community-level responses to the disease are expected. However, predicting the specific impacts and time course of change across west coast meta-communities is difficult, suggesting the need for

  2. An analysis of a zooplankton sampling-gear change in the CalCOFI long-term monitoring program, with implications for copepod population abundance trends

    NASA Astrophysics Data System (ADS)

    Rebstock, Ginger A.

    The California Cooperative Oceanic Fisheries Investigations (CalCOFI) program has been systematically sampling zooplankton off the west coast of North America since 1949. In 1978, the 1-m diameter ring net used by the program was replaced with a bongo net, which consists of two 0.71-m diameter nets on a single frame. This study compares paired zooplankton samples taken with a ring net and a 0.71-m or 0.6-m bongo net to determine the relative performances of the two net types for catching calanoid copepods. Thirty-one species and stages were enumerated, along with the category ‘total female calanoids’. Twenty-one categories of calanoid copepods were abundant enough to test for effects of changes in net type. No significant differences between the nets were found after correcting for multiple testing. Statistical power was then estimated for a range of potential net effects equivalent to ratios of copepod densities between the nets of 1.1-3.0. The probability of detecting differences greater than a factor of 1.5-3.0 was high (≥80%) for total female calanoids, Metridia pacifica, Pleuromamma abdominalis edentata, P. borealis, Calanus pacificus, Eucalanus californicus and Rhincalanus nasutus. For these categories of copepods, any population changes greater than a factor of 1.5-3.0 that might be found from the CalCOFI data set can be assumed to be the result of factors other than the change in net type.

  3. Long-term performance of rapid oxidation of arsenite in simulated groundwater using a population of arsenite-oxidizing microorganisms in a bioreactor.

    PubMed

    Li, Hao; Zeng, Xian-Chun; He, Zhong; Chen, Xiaoming; E, Guoji; Han, Yiyang; Wang, Yanxin

    2016-09-15

    A population of arsenite-oxidizing microorganisms enriched from the tailing of the Shimen realgar mine was used to generate biofilms on the surfaces of perlites. This bioreactor is able to completely oxidize 1100 μg/L As(III) dissolved in simulated groundwater into As(V) within 10 min; after 140 days of operation, approximately 20 min were required to completely oxidize the same concentration of As(III). Analysis for the 16S rRNA genes of the microbial community showed that Bacteroidetes and Proteobacteria are dominant in the reactor. Six different bacterial strains were randomly isolated from the reactor. Function and gene analysis indicated that all the isolates possess arsenite-oxidizing activity, and five of them are chemoautotrophic. Further analysis showed that a large diversity of AioAs and two types of RuBisCOs are present in the microbial community. This suggests that many chemoautotrophic arsenite-oxidizing microorganisms were responsible for quick oxidation of arsenite in the reactor. We also found that the reactor is easily regenerated and its number is readily expanded. To the best of our knowledge, the arsenite-oxidizing efficiency, which was expressed as the minimum time for complete oxidization of a certain concentration of As(III) under a single operation, of this bioreactor is the highest among the described bioreactors; it is also the most stable, economic and environment-friendly.

  4. Long-term performance of rapid oxidation of arsenite in simulated groundwater using a population of arsenite-oxidizing microorganisms in a bioreactor.

    PubMed

    Li, Hao; Zeng, Xian-Chun; He, Zhong; Chen, Xiaoming; E, Guoji; Han, Yiyang; Wang, Yanxin

    2016-09-15

    A population of arsenite-oxidizing microorganisms enriched from the tailing of the Shimen realgar mine was used to generate biofilms on the surfaces of perlites. This bioreactor is able to completely oxidize 1100 μg/L As(III) dissolved in simulated groundwater into As(V) within 10 min; after 140 days of operation, approximately 20 min were required to completely oxidize the same concentration of As(III). Analysis for the 16S rRNA genes of the microbial community showed that Bacteroidetes and Proteobacteria are dominant in the reactor. Six different bacterial strains were randomly isolated from the reactor. Function and gene analysis indicated that all the isolates possess arsenite-oxidizing activity, and five of them are chemoautotrophic. Further analysis showed that a large diversity of AioAs and two types of RuBisCOs are present in the microbial community. This suggests that many chemoautotrophic arsenite-oxidizing microorganisms were responsible for quick oxidation of arsenite in the reactor. We also found that the reactor is easily regenerated and its number is readily expanded. To the best of our knowledge, the arsenite-oxidizing efficiency, which was expressed as the minimum time for complete oxidization of a certain concentration of As(III) under a single operation, of this bioreactor is the highest among the described bioreactors; it is also the most stable, economic and environment-friendly. PMID:27288673

  5. Stochastic weighted particle methods for population balance equations

    SciTech Connect

    Patterson, Robert I.A.; Wagner, Wolfgang; Kraft, Markus

    2011-08-10

    Highlights: {yields} Weight transfer functions for Monte Carlo simulation of coagulation. {yields} Efficient support for single-particle growth processes. {yields} Comparisons to analytic solutions and soot formation problems. {yields} Better numerical accuracy for less common particles. - Abstract: A class of coagulation weight transfer functions is constructed, each member of which leads to a stochastic particle algorithm for the numerical treatment of population balance equations. These algorithms are based on systems of weighted computational particles and the weight transfer functions are constructed such that the number of computational particles does not change during coagulation events. The algorithms also facilitate the simulation of physical processes that change single particles, such as growth, or other surface reactions. Four members of the algorithm family have been numerically validated by comparison to analytic solutions to simple problems. Numerical experiments have been performed for complex laminar premixed flame systems in which members of the class of stochastic weighted particle methods were compared to each other and to a direct simulation algorithm. Two of the weighted algorithms have been shown to offer performance advantages over the direct simulation algorithm in situations where interest is focused on the larger particles in a system. The extent of this advantage depends on the particular system and on the quantities of interest.

  6. Characterization of chlordecone-tolerant fungal populations isolated from long-term polluted tropical volcanic soil in the French West Indies.

    PubMed

    Merlin, Chloé; Devers, Marion; Crouzet, Olivier; Heraud, Cécile; Steinberg, Christian; Mougin, Christian; Martin-Laurent, Fabrice

    2014-04-01

    The insecticide chlordecone is a contaminant found in most of the banana plantations in the French West Indies. This study aims to search for fungal populations able to grow on it. An Andosol heavily contaminated with chlordecone, perfused for 1 year in a soil-charcoal system, was used to conduct enrichment cultures. A total of 103 fungal strains able to grow on chlordecone-mineral salt medium were isolated, purified, and deposited in the MIAE collection (Microorganismes d'Intérêt Agro-Environnemental, UMR Agroécologie, Institut National de la Recherche Agronomique, Dijon, France). Internal transcribed spacer sequencing revealed that all isolated strains belonged to the Ascomycota phylum and gathered in 11 genera: Metacordyceps, Cordyceps, Pochonia, Acremonium, Fusarium, Paecilomyces, Ophiocordyceps, Purpureocillium, Bionectria, Penicillium, and Aspergillus. Among predominant species, only one isolate, Fusarium oxysporum MIAE01197, was able to grow in a liquid culture medium that contained chlordecone as sole carbon source. Chlordecone increased F. oxysporum MIAE01197 growth rate, attesting for its tolerance to this organochlorine. Moreover, F. oxysporum MIAE01197 exhibited a higher EC50 value than the reference strain F. oxysporum MIAE00047. This further suggests its adaptation to chlordecone tolerance up to 29.2 mg l(-1). Gas chromatography-mass spectrometry (GC-MS) analysis revealed that 40 % of chlordecone was dissipated in F. oxysporum MIAE01197 suspension culture. No chlordecone metabolite was detected by GC-MS. However, weak amount of (14)CO2 evolved from (14)C10-chlordecone and (14)C10-metabolites were observed. Sorption of (14)C10-chlordecone onto fungal biomass followed a linear relationship (r (2) = 0.99) suggesting that it may also account for chlordecone dissipation in F. oxysporum MIAE01197 culture. PMID:23872892

  7. Examining Long-Term Global Climate Change on the Web.

    ERIC Educational Resources Information Center

    Huntoon, Jacqueline E.; Ridky, Robert K.

    2002-01-01

    Describes a web-based, inquiry-oriented activity that enables students to examine long-term global climate change. Supports instruction in other topics such as population growth. (Contains 34 references.) (DDR)

  8. Robustness against extinction by stochastic sex determination in small populations.

    PubMed

    Schneider, David M; do Carmo, Eduardo; Bar-Yam, Yaneer; de Aguiar, Marcus A M

    2012-10-01

    Sexually reproducing populations with a small number of individuals may go extinct by stochastic fluctuations in sex determination, causing all their members to become male or female in a generation. In this work we calculate the time to extinction of isolated populations with fixed number N of individuals that are updated according to the Moran birth and death process. At each time step, one individual is randomly selected and replaced by its offspring resulting from mating with another individual of the opposite sex; the offspring can be male or female with equal probability. A set of N time steps is called a generation, the average time it takes for the entire population to be replaced. The number k of females fluctuates in time, similarly to a random walk, and extinction, which is the only asymptotic possibility, occurs when k=0 or k=N. We show that it takes only one generation for an arbitrary initial distribution of males and females to approach the binomial distribution. This distribution, however, is unstable and the population eventually goes extinct in 2(N)/N generations. We also discuss the robustness of these results against bias in the determination of the sex of the offspring, a characteristic promoted by infection by the bacteria Wolbachia in some arthropod species or by temperature in reptiles.

  9. Robustness against extinction by stochastic sex determination in small populations

    NASA Astrophysics Data System (ADS)

    Schneider, David M.; do Carmo, Eduardo; Bar-Yam, Yaneer; de Aguiar, Marcus A. M.

    2012-10-01

    Sexually reproducing populations with a small number of individuals may go extinct by stochastic fluctuations in sex determination, causing all their members to become male or female in a generation. In this work we calculate the time to extinction of isolated populations with fixed number N of individuals that are updated according to the Moran birth and death process. At each time step, one individual is randomly selected and replaced by its offspring resulting from mating with another individual of the opposite sex; the offspring can be male or female with equal probability. A set of N time steps is called a generation, the average time it takes for the entire population to be replaced. The number k of females fluctuates in time, similarly to a random walk, and extinction, which is the only asymptotic possibility, occurs when k=0 or k=N. We show that it takes only one generation for an arbitrary initial distribution of males and females to approach the binomial distribution. This distribution, however, is unstable and the population eventually goes extinct in 2N/N generations. We also discuss the robustness of these results against bias in the determination of the sex of the offspring, a characteristic promoted by infection by the bacteria Wolbachia in some arthropod species or by temperature in reptiles.

  10. Impact of local surgical treatment on survival in young women with T1 breast cancer: long-term results of a population-based cohort.

    PubMed

    Jeon, Ye Won; Choi, Jung Eun; Park, Heung Kyu; Kim, Ku Sang; Lee, Jee Yeon; Suh, Young Jin

    2013-04-01

    The aim of this study was to analyze the effect of the type of local surgical treatment on survival in young women aged less than 40 years with T1 breast cancer. We analyzed data from 3,512 patients aged ≤40 years old who were diagnosed with T1 breast cancer from the Korean Breast Cancer Registry database between January 1988 and December 2006 and underwent either breast-conserving therapy (BCT) or mastectomy. The overall survival (OS) and breast-cancer-specific survival (BCSS) were compared between BCT and mastectomy. Of the 3,512 patients analyzed, 1,951 (55.6 %) underwent BCT, and 1,561 (44.4 %) underwent mastectomy. The median follow-up period was 111.0 (79.0-131.5) months. Overall, the 10-year OS rates for BCT and mastectomy were 95 and 92.1 %, respectively (p = 00004), and the 10-year BCSS rates for BCT and mastectomy patients were 96.9 and 94.9 %, respectively (p = 0.12). In node-negative patients, no significant difference was observed in either the OS (adjusted hazard ratio [HR] 1.072; 95 % CI, 0.750-1.5332, p = 0.704) or BCSS (adjusted HR 0.988; 95 % CI, 0.620-1.574, p = 0.960) rate between the BCT and mastectomy groups. In node-positive patients, no significant difference was observed in the OS (adjusted HR 1.634; 95 % CI, 0.982-2.272, p = 0.59) and BCSS (adjusted HR 1.410; 95 % CI, 0.755-2.633, p = 0.281) rates between the BCT and mastectomy groups. In this large, population-based analysis of young women with T1 breast cancer, the OS and BCSS were not different between BCT and mastectomy. PMID:23456232

  11. Long term survival with stereotactic ablative radiotherapy (SABR) versus thoracoscopic sublobar lung resection in elderly people: national population based study with propensity matched comparative analysis

    PubMed Central

    Paul, Subroto; Lee, Paul C; Mao, Jialin; Isaacs, Abby J

    2016-01-01

    Objectives To compare cancer specific survival after thoracoscopic sublobar lung resection and stereotactic ablative radiotherapy (SABR) for tumors ≤2 cm in size and thoracoscopic resection (sublobar resection or lobectomy) and SABR for tumors ≤5 cm in size. Design National population based retrospective cohort study with propensity matched comparative analysis. Setting Surveillance, Epidemiology, and End Results (SEER) registry linked with Medicare database in the United States. Participants Patients aged ≥66 with lung cancer undergoing SABR or thoracoscopic lobectomy or sublobar resection from 1 Oct 2007 to 31 June 2012 and followed up to 31 December 2013. Main outcome measures Cancer specific survival after SABR or thoracoscopic surgery for lung cancer. Results 690 (275 (39.9%) SABR and 415 (60.1%) thoracoscopic sublobar lung resection) and 2967 (714 (24.1%) SABR and 2253 (75.9%) thoracoscopic resection) patients were included in primary and secondary analyses. The average age of the entire cohort was 76. Follow-up of the entire cohort ranged from 0 to 6.25 years, with an average of three years. In the primary analysis of patients with tumors sized ≤2 cm, 37 (13.5%) undergoing SABR and 44 (10.6%) undergoing thoracoscopic sublobar resection died from lung cancer, respectively. The cancer specific survival diverged after one year, but in the matched analysis (201 matched patients in each group) there was no significant difference between the groups (SABR v sublobar lung resection mortality: hazard ratio 1.32, 95% confidence interval 0.77 to 2.26; P=0.32). Estimated cancer specific survival at three years after SABR and thoracoscopic sublobar lung resection was 82.6% and 86.4%, respectively. The secondary analysis (643 matched patients in each group) showed that thoracoscopic resection was associated with improved cancer specific survival over SABR in patients with tumors sized ≤5 cm (SABR v resection mortality: hazard ratio 2.10, 1.52 to 2.89; P<0

  12. Complex Population Dynamics in Mussels Arising from Density-Linked Stochasticity

    PubMed Central

    Wootton, J. Timothy; Forester, James D.

    2013-01-01

    Population fluctuations are generally attributed to the deterministic consequences of strong non-linear interactions among organisms, or the effects of random stochastic environmental variation superimposed upon the deterministic skeleton describing population change. Analysis of the population dynamics of the mussel Mytilus californianus taken in 16 plots over 18-years found no evidence that these processes explained observed strong fluctuations. Instead, population fluctuations arose because environmental stochasticity varied with abundance, which we term density-linked stochasticity. This phenomenon arises from biologically relevant mechanisms: recruitment variation and transmission of disturbance among neighboring individuals. Density-linked stochasticity is probably present frequently in populations, as it arises naturally from several general ecological processes, including stage structure variation with density, ontogenetic niche shifts, and local transmission of stochastic perturbations. More thoroughly characterizing and interpreting deviations from the mean behavior of a system will lead to better ecological prediction and improved insight into the important processes affecting populations and ecosystems. PMID:24086617

  13. Long-Term Care Policy: Singapore's Experience.

    PubMed

    Chin, Chee Wei Winston; Phua, Kai-Hong

    2016-01-01

    Singapore, like many developed countries, is facing the challenge of a rapidly aging population and the increasing need to provide long-term care (LTC) services for elderly in the community. The Singapore government's philosophy on care for the elderly is that the family should be the first line of support, and it has relied on voluntary welfare organizations (VWOs) or charities for the bulk of LTC service provision. For LTC financing, it has emphasized the principles of co-payment and targeting of state support to the low-income population through means-tested government subsidies. It has also instituted ElderShield, a national severe disability insurance scheme. This paper discusses some of the challenges facing LTC policy in Singapore, particularly the presence of perverse financial incentives for hospitalization, the pitfalls of over-reliance on VWOs, and the challenges facing informal family caregivers. It discusses the role of private LTC insurance in LTC financing, bearing in mind demand- and supply-side failures that have plagued the private LTC insurance market. It suggests the need for more standardized needs assessment and portable LTC benefits, with reference to the Japanese Long-Term Care Insurance program, and also discusses the need to provide more support to informal family caregivers. PMID:26808468

  14. Stochastic stability and the evolution of coordination in spatially structured populations.

    PubMed

    Van Cleve, Jeremy; Lehmann, Laurent

    2013-11-01

    Animals can often coordinate their actions to achieve mutually beneficial outcomes. However, this can result in a social dilemma when uncertainty about the behavior of partners creates multiple fitness peaks. Strategies that minimize risk ("risk dominant") instead of maximizing reward ("payoff dominant") are favored in economic models when individuals learn behaviors that increase their payoffs. Specifically, such strategies are shown to be "stochastically stable" (a refinement of evolutionary stability). Here, we extend the notion of stochastic stability to biological models of continuous phenotypes at a mutation-selection-drift balance. This allows us to make a unique prediction for long-term evolution in games with multiple equilibria. We show how genetic relatedness due to limited dispersal and scaled to account for local competition can crucially affect the stochastically-stable outcome of coordination games. We find that positive relatedness (weak local competition) increases the chance the payoff dominant strategy is stochastically stable, even when it is not risk dominant. Conversely, negative relatedness (strong local competition) increases the chance that strategies evolve that are neither payoff nor risk dominant. Extending our results to large multiplayer coordination games we find that negative relatedness can create competition so extreme that the game effectively changes to a hawk-dove game and a stochastically stable polymorphism between the alternative strategies evolves. These results demonstrate the usefulness of stochastic stability in characterizing long-term evolution of continuous phenotypes: the outcomes of multiplayer games can be reduced to the generic equilibria of two-player games and the effect of spatial structure can be analyzed readily.

  15. Long Term Surface Salinity Measurements

    NASA Technical Reports Server (NTRS)

    Schmitt, Raymond W.; Brown, Neil L.

    2005-01-01

    Our long-term goal is to establish a reliable system for monitoring surface salinity around the global ocean. Salinity is a strong indicator of the freshwater cycle and has a great influence on upper ocean stratification. Global salinity measurements have potential to improve climate forecasts if an observation system can be developed. This project is developing a new internal field conductivity cell that can be protected from biological fouling for two years. Combined with a temperature sensor, this foul-proof cell can be deployed widely on surface drifters. A reliable in-situ network of surface salinity sensors will be an important adjunct to the salinity sensing satellite AQUARIUS to be deployed by NASA in 2009. A new internal-field conductivity cell has been developed by N Brown, along with new electronics. This sensor system has been combined with a temperature sensor to make a conductivity - temperature (UT) sensor suitable for deployment on drifters. The basic sensor concepts have been proven on a high resolution CTD. A simpler (lower cost) circuit has been built for this application. A protection mechanism for the conductivity cell that includes antifouling protection has also been designed and built. Mr. A.Walsh of our commercial partner E-Paint has designed and delivered time-release formulations of antifoulants for our application. Mr. G. Williams of partner Clearwater Instrumentation advised on power and communication issues and supplied surface drifters for testing.

  16. Long-term equilibrium tides

    NASA Astrophysics Data System (ADS)

    Shaffer, John A.; Cerveny, Randall S.

    1998-08-01

    Extreme equilibrium tides, or ``hypertides,'' are computed in a new equilibrium tidal model combining algorithms of a version of the Chapront ELP-2000/82 Lunar Theory with the BER78 Milankovitch astronomical expansions. For the recent past, a high correspondence exists between computed semidiurnal tide levels and a record of coastal flooding demonstrating that astronomical alignment is a potential influence on such flooding. For the Holocene and near future, maximum tides demonstrate cyclic variations with peaks at near 5000 B.P. and 4000 A.P. On the late Quaternary timescale, variations in maximum equilibrium tide level display oscillations with periods of approximately 10,000, 100,000 and 400,000 years, because of precessional shifts in tidal maxima between vernal and autumnal equinoxes. While flooding occurs under the combined effects of tides and storms via ``storm surges,'' the most extensive flooding will occur with the coincidence of storms and the rarer hypertides and is thus primarily influenced by hypertides. Therefore we suggest that astronomical alignment's relationship to coastal flooding is probabilistic rather than deterministic. Data derived from this model are applicable to (1) archaeological and paleoclimatic coastal reconstructions, (2) long-term planning, for example, radioactive waste site selection, (3) sealevel change and paleoestuarine studies or (4) ocean-meteorological interactions.

  17. Long-Term Planning in Higher Education.

    ERIC Educational Resources Information Center

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

    This report presents the concepts and issues discussed at a Regional Symposium on Long-term Planning in Higher Education held in Dhaka, Bangladesh, September 21-30, 1986. Chapter 1 explores some fundamental issues about the rationale for the objectives of long-term planning. It defines long-term planning in higher education, considers its…

  18. Long term prediction of flood occurrence

    NASA Astrophysics Data System (ADS)

    Aguilar, Cristina; Montanari, Alberto; José Polo, María

    2016-05-01

    How long a river remembers its past is still an open question. Perturbations occurring in large catchments may impact the flow regime for several weeks and months, therefore providing a physical explanation for the occasional tendency of floods to occur in clusters. The research question explored in this paper may be stated as follows: can higher than usual river discharges in the low flow season be associated to a higher probability of floods in the subsequent high flow season? The physical explanation for such association may be related to the presence of higher soil moisture storage at the beginning of the high flow season, which may induce lower infiltration rates and therefore higher river runoff. Another possible explanation is persistence of climate, due to presence of long-term properties in atmospheric circulation. We focus on the Po River at Pontelagoscuro, whose catchment area amounts to 71 000 km2. We look at the stochastic connection between average river flows in the pre-flood season and the peak flows in the flood season by using a bivariate probability distribution. We found that the shape of the flood frequency distribution is significantly impacted by the river flow regime in the low flow season. The proposed technique, which can be classified as a data assimilation approach, may allow one to reduce the uncertainty associated to the estimation of the flood probability.

  19. Influenza in long-term care facilities: preventable, detectable, treatable.

    PubMed

    Mossad, Sherif B

    2009-09-01

    Influenza in long-term care facilities is an ever more challenging problem. Vaccination of residents and health care workers is the most important preventive measure. Although vaccine efficacy has been questioned, the preponderance of data favors vaccination. Antiviral resistance complicates postexposure chemoprophylaxis and treatment. Factors that limit the choice of antiviral agents in this patient population include limited vaccine supplies and impaired dexterity and confusion in long-term care residents. PMID:19726556

  20. Long-term mechanical ventilation and nutrition.

    PubMed

    Ambrosino, Nicolino; Clini, Enrico

    2004-05-01

    Mechanical ventilation (MV) in chronic situations is commonly used, either delivered invasively or by means of non-invasive interfaces, to control hypoventilation in patients with chest wall, neuromuscular or obstructive lung diseases (either in adulthood or childhood). The global prevalence of ventilator-assisted individuals (VAI) in Europe ranges from 2 to 30 per 100000 population according to different countries. Nutrition is a common problem to face with in patients with chronic respiratory diseases: nonetheless, it is a key component in the long-term management of underweight COPD patients whose muscular disfunction may rapidly turn to peripheral muscle waste. Since long-term mechanical ventilation (LTMV) is usually prescribed in end-stage respiratory diseases with poor nutritional status, nutrition and dietary intake related problems need to be carefully assessed and corrected in these patients. This paper aims to review the most recent innovations in the field of nutritional status and food intake-related problems of VAI (both in adulthood and in childhood).

  1. Role of healthcare in Korean long-term care insurance.

    PubMed

    Kang, Im-Oak; Park, Chong Yon; Lee, Yunhwan

    2012-05-01

    With the rapid aging of the population, Korea introduced public long-term care insurance for older people in 2008. The long-term care insurance was designed as a separate scheme from the national health insurance, with eligibility qualifications and the certification process based on functional disability, benefits and coverage of community-based and institutional care, and a financing structure through multi-party contributions. Delivering appropriate health services to long-term care beneficiaries who manifest a high prevalence of comorbid chronic conditions with rising healthcare costs, however, presents a particular challenge. The lack of coordination between the health and long-term care sectors, limited consideration of physicians' assessments in the certification process, inadequate provision of health services in long-term care facilities, and overlapping and inefficient use of care resources act as barriers to providing comprehensive healthcare for older beneficiaries. Through active participation in the long-term care system, health professionals can help older patients navigate through the complex long-term care terrain to obtain quality healthcare.

  2. Safety of long-term PPI therapy.

    PubMed

    Reimer, Christina

    2013-06-01

    Proton pump inhibitors have become the mainstay of medical treatment of acid-related disorders. Long-term use is becoming increasingly common, in some cases without a proper indication. A large number of mainly observational studies on a very wide range of possible associations have been published in the past decade and are critically reviewed in this article and the existing evidence is evaluated and translated into possible clinical consequences. Based on the existing evidence the benefits of PPI treatment seem to outweigh potential risks in the large majority of patients especially if PPI use is based on a relevant indication. The concern for complications should primarily be directed at elderly, malnourished with significant co-morbidity. In this population an increased risk for enteric infections, fractures and nutritional deficiencies might have clinical consequences and should lead to a careful evaluation of the indication for PPI treatment. PMID:23998981

  3. Scientific Understanding from Long Term Observations: Insights from the Long Term Ecological Research (LTER) Program

    NASA Astrophysics Data System (ADS)

    Gosz, J.

    2001-12-01

    estuaries below by removing all incoming freshwater. At Toolik Lake, long-term experiments of removing top predators from the good web of lakes showed dramatic alterations of lake populations of small fish and zooplankton. In New Mexico, LTER research on small mammal populations is successfully predicting rodent increases and the potential for increased zoonotic diseases such as Hantavirus and bubonic plague. This ability to forecast based on El Nino prediction is being used to increase scientific awareness and public health awareness through media based communication with the public. In Oregon, the Andrews Forest LTER program has had long, strong links with natural resource policy and management. Basic understanding of forest-stream interactions, characteristics of old-growth forests, roles of woody debris in temperate forest ecosystems, invertebrate biodiversity and ecosystem function have been incorporated in management guidelines, plans and regulations for public and private lands throughout the Pacific Northwest. Other examples of the values of long-term research and monitoring will be presented.

  4. The UCLA population studies of chronic obstructive respiratory disease. IV. Respiratory effect of long-term exposure to photochemical oxidants, nitrogen dioxide, and sulfates on current and never smokers

    SciTech Connect

    Detels, R.; Sayre, J.W.; Coulson, A.H.; Rokaw, S.N.; Massey, F.J. Jr.; Tashkin, D.P.; Wu, M.M.

    1981-12-01

    Questionnaires, spirometry, and the single-breath nitrogen test were administered to 3,192 participants 25 to 39 yr of age in area exposed to low concentrations of all pollutants (Lancaster, California) and to 2,369 similar participants living in an area exposed to high concentrations of photochemical oxidants, nitrogen dioxide, and sulfates (Glendora, California). The prevalence of symptoms and results in the majority of the tests were worse in the polluted area between current and never smokers and men and women. Those tests associated primarily with small airways (Vmax50, Vmax75, delta N 2(750-1250) showed little or no difference between areas. The difference in the prevalence of participants with a poor FEV1 and/or poor FEV1 and/or poor FVC and in the mean Vmax and closing volume was greater between areas than between smoking categories. These results suggest that long-term exposure to high concentrations of photochemical oxidants, NO2, and sulfates at place of residence may result in measurable impairment in both current smokers and never smokers. Firmer documentation of this effect will require following these populations for changes in lung function that correlate with pollutant exposures.

  5. High quality long-term CD4+ and CD8+ effector memory populations stimulated by DNA-LACK/MVA-LACK regimen in Leishmania major BALB/c model of infection.

    PubMed

    Sánchez-Sampedro, Lucas; Gómez, Carmen Elena; Mejías-Pérez, Ernesto; Sorzano, Carlos Oscar S; Esteban, Mariano

    2012-01-01

    Heterologous vaccination based on priming with a plasmid DNA vector and boosting with an attenuated vaccinia virus MVA recombinant, with both vectors expressing the Leishmania infantum LACK antigen (DNA-LACK and MVA-LACK), has shown efficacy conferring protection in murine and canine models against cutaneus and visceral leishmaniasis, but the immune parameters of protection remain ill defined. Here we performed by flow cytometry an in depth analysis of the T cell populations induced in BALB/c mice during the vaccination protocol DNA-LACK/MVA-LACK, as well as after challenge with L. major parasites. In the adaptive response, there is a polyfunctional CD4(+) and CD8(+) T cell activation against LACK antigen. At the memory phase the heterologous vaccination induces high quality LACK-specific long-term CD4(+) and CD8(+) effector memory cells. After parasite challenge, there is a moderate boosting of LACK-specific CD4(+) and CD8(+) T cells. Anti-vector responses were largely CD8(+)-mediated. The immune parameters induced against LACK and triggered by the combined vaccination DNA/MVA protocol, like polyfunctionality of CD4(+) and CD8(+) T cells with an effector phenotype, could be relevant in protection against leishmaniasis. PMID:22715418

  6. Chronic sodium salicylate administration enhances population spike long-term potentiation following a combination of theta frequency primed-burst stimulation and the transient application of pentylenetetrazol in rat CA1 hippocampal neurons.

    PubMed

    Gholami, Masoumeh; Moradpour, Farshad; Semnanian, Saeed; Naghdi, Nasser; Fathollahi, Yaghoub

    2015-11-15

    The effect of chronic administration of sodium salicylate (NaSal) on the excitability and synaptic plasticity of the rodent hippocampus was investigated. Repeated systemic treatment with NaSal reliably induced tolerance to the anti-nociceptive effect of NaSal (one i.p. injection per day for 6 consecutive days). Following chronic NaSal or vehicle treatment, a series of electrophysiological experiments on acute hippocampal slices (focusing on the CA1 circuitry) were tested whether tolerance to NaSal would augment pentylenetetrazol (PTZ)-induced long-term potentiation (LTP) and /or epileptic activity, and whether the augmentation was the same after priming activity with a natural stimulus pattern prior to PTZ. We noted an altered synaptic input-to-spike transformation, such that neuronal firing increased after a given synaptic drive. Population spike-LTP (PS-LTP) was increased in the NaSal-tolerant animals, but only when it was induced via a combination of electrical stimulation (theta pattern primed-burst stimulation) and the transient application of PTZ. Identifying and understanding these changes in neuronal excitability and synaptic plasticity following chronic salicylate treatment could prove useful in the clinical diagnosis or treatment of chronic aspirin-induced, or even idiopathic, seizure activity.

  7. Long-term solar-terrestrial observations

    NASA Technical Reports Server (NTRS)

    1988-01-01

    The results of an 18-month study of the requirements for long-term monitoring and archiving of solar-terrestrial data is presented. The value of long-term solar-terrestrial observations is discussed together with parameters, associated measurements, and observational problem areas in each of the solar-terrestrial links (the sun, the interplanetary medium, the magnetosphere, and the thermosphere-ionosphere). Some recommendations are offered for coordinated planning for long-term solar-terrestrial observations.

  8. Long-Term Economic and Labor Forecast Trends for Washington. 1996.

    ERIC Educational Resources Information Center

    Lefberg, Irv; And Others

    This publication provides actual historical and long-term forecast data on labor force, total wage and salary employment, industry employment, and personal income for the state of Washington. The data are based upon the Washington Office of Financial Management long-term population forecast. Chapter 1 presents long-term forecasts of Washington…

  9. Effects of stochastic population fluctuations in two models of biological macroevolution

    NASA Astrophysics Data System (ADS)

    Murase, Yohsuke; Shimada, Takashi; Ito, Nobuyasu; Rikvold, Per Arne

    Two mathematical models of macroevolution are studied. These models have population dynamics at the species level, and mutations and extinction of species are also included. The population dynamics are updated by difference equations with stochastic noise terms that characterize population fluctuations. The effects of the stochastic population fluctuations on diversity and total population sizes on evolutionary time scales are studied. In one model, species can make either predator-prey, mutualistic, or competitive interactions, while the other model allows only predator-prey interactions. When the noise in the population dynamics is strong enough, both models show intermittent behavior and their power spectral densities show approximate 1/f fluctuations. In the noiseless limit, the two models have different power spectral densities. For the predator-prey model, 1/f2 fluctuations appears, indicating random-walk like behavior, while the other model still shows 1/f noise. These results indicate that stochastic population fluctuations may significantly affect long-time evolutionary dynamics.

  10. Impact of stochasticity in immigration and reintroduction on colonizing and extirpating populations.

    PubMed

    Rajakaruna, Harshana; Potapov, Alexei; Lewis, Mark

    2013-05-01

    A thorough quantitative understanding of populations at the edge of extinction is needed to manage both invasive and extirpating populations. Immigration can govern the population dynamics when the population levels are low. It increases the probability of a population establishing (or reestablishing) before going extinct (EBE). However, the rate of immigration can be highly fluctuating. Here, we investigate how the stochasticity in immigration impacts the EBE probability for small populations in variable environments. We use a population model with an Allee effect described by a stochastic differential equation (SDE) and employ the Fokker-Planck diffusion approximation to quantify the EBE probability. We find that, the effect of the stochasticity in immigration on the EBE probability depends on both the intrinsic growth rate (r) and the mean rate of immigration (p). In general, if r is large and positive (e.g. invasive species introduced to favorable habitats), or if p is greater than the rate of population decline due to the demographic Allee effect (e.g., effective stocking of declining populations), then the stochasticity in immigration decreases the EBE probability. If r is large and negative (e.g. endangered populations in unfavorable habitats), or if the rate of decline due to the demographic Allee effect is much greater than p (e.g., weak stocking of declining populations), then the stochasticity in immigration increases the EBE probability. However, the mean time for EBE decreases with the increasing stochasticity in immigration with both positive and negative large r. Thus, results suggest that ecological management of populations involves a tradeoff as to whether to increase or decrease the stochasticity in immigration in order to optimize the desired outcome. Moreover, the control of invasive species spread through stochastic means, for example, by stochastic monitoring and treatment of vectors such as ship-ballast water, may be suitable strategies

  11. Commentary: The Broader Context of Long-Term Care Ethics.

    PubMed

    Lesandrini, Jason; O'Connell, Carol

    2016-07-01

    Ethical issues in long-term care settings, although having received attention in the literature, have not in our opinion received the appropriate level they require. Thus, we applaud the Cambridge Quarterly for publishing this case. We can attest to the significance of ethical issues arising in long-term care facilities, as Mr. Hope's case is all too familiar to those practicing in these settings. What is unique about this case is that an actual ethics consult was made in a long-term care setting. We have seen very little in the published literature on the use of ethics structures in long-term care populations. Our experience is that these healthcare settings are ripe for ethical concerns and that providers, patients, families, and staff need/desire ethics resources to actively and preventively address ethical concerns. The popular press has begun to recognize the ethical issues involved in long-term care settings and the need for ethics structures. Recently, in California a nurse refused to initiate CPR for an elderly patient in a senior residence. In that case, the nurse was quoted as saying that the facility had a policy that nurses were not to start CPR for elderly patients. 1 Although this case is not exactly the same as that of Mr. Hope, it highlights the need for developing robust ethics program infrastructures in long-term care settings that work toward addressing ethical issues through policy, education, and active consultation.

  12. Private Financing Options for Long-term Care

    PubMed Central

    Brody, Barbara L.; Simon, Harold J.; Smallwood, Dennis E.

    1987-01-01

    Private financing for long-term care now comes almost exclusively from out-of-pocket payments. Long-term-care costs quickly impoverish most elderly, resulting in Medicaid dependency. The consequences are profound for the western Sun Belt with its rapidly growing elderly population. Key private financing options are long-term-care individual retirement accounts (LTC/IRAs), home equity conversion, social-health maintenance organizations and long-term-care insurance. Study of data from the past half century suggests that the LTC/IRA approach would prove unsatisfactory for the purpose despite the intuitive appeal of this mechanism. Experience with home equity conversions is still very limited, and unresolved questions limit this approach to the role of a reserve option for now. While promising, social-health maintenance organizations are still in the experimental stages and not yet commercially available. Long-term-care insurance is currently sold on a thin market and emphasizes nursing home coverage. New approaches to private financing through long-term-care insurance seem to offer the best approach for immediate implementation. PMID:3118576

  13. Long-term memory of atmospheric aerosols over India

    NASA Astrophysics Data System (ADS)

    B, A.

    2014-12-01

    Long-term memory of atmospheric variables is a least understood facet in atmospheric science. The temporal and spatial distribution of atmospheric aerosols depends largely on the atmospheric parameters. Time series analysis using a stochastic model reveals that atmospheric aerosols over India exhibit a long-term memory. Our analysis confirms that by using Autoregressive Integrated Moving Average (ARIMA) model we can parsimoniously model the aerosol optical depth (AOD) over the Indian region with a reasonably good accuracy. This major advantage of this method is that by using past observations we were able to generate forecasts for next 3 years. The forecasts thus generate shows a good fit with the observations. This persistence is due to the presence of temporal dependence between successive observations.

  14. Financing long-term care in Canada.

    PubMed

    Jacobs, P; Mills, C; Hollander, M

    1997-06-01

    Financial policies relating to long-term care in Canada are changing rapidly in response to demands for health care reform. This chapter focuses on the financial structure of institutional care, primarily nursing homes, in the western provinces of Alberta and British Columbia. Community-based long-term care is discussed briefly.

  15. Virtual Models of Long-Term Care

    ERIC Educational Resources Information Center

    Phenice, Lillian A.; Griffore, Robert J.

    2012-01-01

    Nursing homes, assisted living facilities and home-care organizations, use web sites to describe their services to potential consumers. This virtual ethnographic study developed models representing how potential consumers may understand this information using data from web sites of 69 long-term-care providers. The content of long-term-care web…

  16. Long-term preservation of Anammox bacteria

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Deposit of useful microorganisms in culture collections requires long-term preservation and successful reactivation techniques. The goal of this study was to develop a simple preservation protocol for the long-term storage and reactivation of the anammox biomass. To achieve this, anammox biomass w...

  17. Forecasting demand for long-term care services.

    PubMed Central

    Lane, D; Uyeno, D; Stark, A; Kliewer, E; Gutman, G

    1985-01-01

    This article analyzes three methods used to forecast the transition of long-term care clients through a variety of possible home and facility placements and levels of care. The test population (N = 1,653) is derived from the larger population of clients admitted in 1978 to British Columbia's newly established Long-Term Care program. The investigators have accumulated 5 years of service-generated data on moves, discharges, and deaths of these clients. Results show that the first-order Markov chain with stationary transition probabilities yields a superior forecast to state-by-state moving average growth and state-by-state regression analyses. The results of these analyses indicate that the Markov method should receive serious consideration as a tool for resource planning and allocation in long-term care. PMID:3932260

  18. Paying for long-term care.

    PubMed Central

    Estes, C L; Bodenheimer, T

    1994-01-01

    Everyone agrees that insurance for long-term care is inadequate in the United States. Disagreement exists, however, on whether such insurance should be provided through the private or public sector. Private insurance generally uses the experience-rating principle that persons with higher risk of illness are charged higher premiums. For private insurance for long-term care, this principle creates a dilemma. Most policies will be purchased by the elderly; yet, because the elderly have a high risk of needing long-term care, only about 20% of them can afford the cost of premiums. A public-private partnership by which the government partially subsidizes private long-term-care insurance is unlikely to resolve this dilemma. Only a social insurance program for long-term care can provide universal, affordable, and equitable coverage. PMID:8128712

  19. Epidemics on networks with heterogeneous population and stochastic infection rates.

    PubMed

    Bonaccorsi, Stefano; Ottaviano, Stefania

    2016-09-01

    In this paper we study the diffusion of an SIS-type epidemics on a network under the presence of a random environment, that enters in the definition of the infection rates of the nodes. Accordingly, we model the infection rates in the form of independent stochastic processes. To analyze the problem, we apply a mean field approximation, which allows to get a stochastic differential equations for the probability of infection in each node, and classical tools about stability, which require to find suitable Lyapunov's functions. Here, we find conditions which guarantee, respectively, extinction and stochastic persistence of the epidemics. We show that there exists two regions, given in terms of the coefficients of the model, one where the system goes to extinction almost surely, and the other where it is stochastic permanent. These two regions are, unfortunately, not adjacent, as there is a gap between them, whose extension depends on the specific level of noise. In this last region, we perform numerical analysis to suggest the true behavior of the solution. PMID:27404211

  20. The Association Between Self-Assessed Future Work Ability and Long-Term Sickness Absence, Disability Pension and Unemployment in a General Working Population: A 7-Year Follow-Up Study.

    PubMed

    Lundin, A; Kjellberg, K; Leijon, O; Punnett, L; Hemmingsson, T

    2016-06-01

    Purpose Work ability is commonly measured with self-assessments, in the form of indices or single items. The validity of these assessments lies in their predictive ability. Prospective studies have reported associations between work ability and sickness absence and disability pension, but few examined why these associations exist. Several correlates of work ability have been reported, but their mechanistic role is largely unknown. This study aims to investigate to what extent individual's own prognosis of work ability predicts labor market participation and whether this was due to individual characteristics and/or working conditions. Methods Self-assessed prognosis of work ability, 2 years from "now," in the Stockholm Public Health Questionnaire (2002-2003) was linked to national registers on sickness absence, disability pension and unemployment up to year 2010. Effects were studied with Cox regression models. Results Of a total of 12,064 individuals 1466 reported poor work ability. There were 299 cases of disability pension, 1466 long-term sickness absence cases and 765 long-term unemployed during follow-up. Poor work ability increased the risk of long-term sickness absence (HR 2.25, CI 95 % 1.97-2.56), disability pension (HR 5.19, CI 95 % 4.07-6.62), and long-term unemployment (HR 2.18, CI 95 % 1.83-2.60). These associations were partially explained by baseline health conditions, physical and (less strongly) psychosocial aspects of working conditions. Conclusions Self-assessed poor ability predicted future long-term sickness absence, disability pension and long-term unemployment. Self-assessed poor work ability seems to be an indicator of future labor market exclusion of different kinds, and can be used in public health monitoring.

  1. The Association Between Self-Assessed Future Work Ability and Long-Term Sickness Absence, Disability Pension and Unemployment in a General Working Population: A 7-Year Follow-Up Study.

    PubMed

    Lundin, A; Kjellberg, K; Leijon, O; Punnett, L; Hemmingsson, T

    2016-06-01

    Purpose Work ability is commonly measured with self-assessments, in the form of indices or single items. The validity of these assessments lies in their predictive ability. Prospective studies have reported associations between work ability and sickness absence and disability pension, but few examined why these associations exist. Several correlates of work ability have been reported, but their mechanistic role is largely unknown. This study aims to investigate to what extent individual's own prognosis of work ability predicts labor market participation and whether this was due to individual characteristics and/or working conditions. Methods Self-assessed prognosis of work ability, 2 years from "now," in the Stockholm Public Health Questionnaire (2002-2003) was linked to national registers on sickness absence, disability pension and unemployment up to year 2010. Effects were studied with Cox regression models. Results Of a total of 12,064 individuals 1466 reported poor work ability. There were 299 cases of disability pension, 1466 long-term sickness absence cases and 765 long-term unemployed during follow-up. Poor work ability increased the risk of long-term sickness absence (HR 2.25, CI 95 % 1.97-2.56), disability pension (HR 5.19, CI 95 % 4.07-6.62), and long-term unemployment (HR 2.18, CI 95 % 1.83-2.60). These associations were partially explained by baseline health conditions, physical and (less strongly) psychosocial aspects of working conditions. Conclusions Self-assessed poor ability predicted future long-term sickness absence, disability pension and long-term unemployment. Self-assessed poor work ability seems to be an indicator of future labor market exclusion of different kinds, and can be used in public health monitoring. PMID:26319413

  2. Globalization, Women's Migration, and the Long-Term-Care Workforce

    ERIC Educational Resources Information Center

    Browne, Colette V.; Braun, Kathryn L.

    2008-01-01

    With the aging of the world's population comes the rising need for qualified direct long-term-care (DLTC) workers (i.e., those who provide personal care to frail and disabled older adults). Developed nations are increasingly turning to immigrant women to fill these needs. In this article, we examine the impact of three global trends--population…

  3. Stochasticity and determinism: how density-independent and density-dependent processes affect population variability.

    PubMed

    Ohlberger, Jan; Rogers, Lauren A; Stenseth, Nils Chr

    2014-01-01

    A persistent debate in population ecology concerns the relative importance of environmental stochasticity and density dependence in determining variability in adult year-class strength, which contributes to future reproduction as well as potential yield in exploited populations. Apart from the strength of the processes, the timing of density regulation may affect how stochastic variation, for instance through climate, translates into changes in adult abundance. In this study, we develop a life-cycle model for the population dynamics of a large marine fish population, Northeast Arctic cod, to disentangle the effects of density-independent and density-dependent processes on early life-stages, and to quantify the strength of compensatory density dependence in the population. The model incorporates information from scientific surveys and commercial harvest, and dynamically links multiple effects of intrinsic and extrinsic factors on all life-stages, from eggs to spawners. Using a state-space approach we account for observation error and stochasticity in the population dynamics. Our findings highlight the importance of density-dependent survival in juveniles, indicating that this period of the life cycle largely determines the compensatory capacity of the population. Density regulation at the juvenile life-stage dampens the impact of stochastic processes operating earlier in life such as environmental impacts on the production of eggs and climate-dependent survival of larvae. The timing of stochastic versus regulatory processes thus plays a crucial role in determining variability in adult abundance. Quantifying the contribution of environmental stochasticity and compensatory mechanisms in determining population abundance is essential for assessing population responses to climate change and exploitation by humans. PMID:24893001

  4. Long-Term Consequences of Neonatal Injury

    PubMed Central

    Beggs, Simon

    2015-01-01

    The maturation of the central nervous system’s (CNS’s) sensory connectivity is driven by modality-specific sensory input in early life. For the somatosensory system, this input is the physical, tactile interaction with the environment. Nociceptive circuitry is functioning at the time of birth; however, there is still considerable organization and refinement of this circuitry that occurs postnatally, before full discrimination of tactile and noxious input is possible. This fine-tuning involves separation of tactile and nociceptive afferent input to the spinal cord’s dorsal horn and the maturation of local and descending inhibitory circuitry. Disruption of that input in early postnatal life (for example, by tissue injury or other noxious stimulus), can have a profound influence on subsequent development, and consequently the mature functioning of pain systems. In this review, the impact of neonatal surgical incision on nociceptive circuitry is discussed in terms of the underlying developmental neurobiology. The changes are complex, occurring at multiple anatomical sites within the CNS, and including both neuronal and glial cell populations. The altered sensory input from neonatal injury selectively modulates neuronal excitability within the spinal cord, disrupts inhibitory control, and primes the immune system, all of which contribute to the adverse long-term consequences of early pain exposure. PMID:26174217

  5. Long-term treatment outcome in acromegaly.

    PubMed

    Holdaway, I M; Rajasoorya, C R; Gamble, G D; Stewart, A W

    2003-08-01

    A number of groups have developed guidelines to indicate whether an individual with acromegaly has been cured by treatment. However, studies to date do not provide a robust definition of biochemical remission of the disorder based on correlation with long-term outcome. Available data suggest that those with a random serum growth hormone (GH) level of <2.5 microg/l, or a glucose-suppressed GH level of <1 microg/l following treatment have mortality figures indistinguishable from the general population. However, the confidence limits for these mortality estimates are quite wide. It remains possible that growth hormone levels lower than 1 microg/l for random samples, or even lower when using ultrasensitive GH assays, may indicate superior outcome, but this remains to be confirmed. There are limited data relating serum insulin-like growth factor-I (IGF-I) levels to outcome, although normalisation of serum IGF-I clearly improves outcome compared with continued elevation of measurements after treatment. Current evidence suggests that a post-treatment random serum GH <2.5 microg/l and a normal serum IGF-I value defines biochemical cure. Available data suggest that achieving similar growth hormone levels after treatment also reduces the prevalence of chronic complications of the disorder, which is subsequently reflected in improved mortality. PMID:12914751

  6. Long Term Effects of Food Poisoning

    MedlinePlus

    ... develop chronic arthritis. Brain and nerve damage A Listeria infection can lead to meningitis, an inflammation of ... brain. If a newborn infant is infected with Listeria , long-term consequences may include mental retardation, seizures, ...

  7. Asthma Medicines: Long-Term Control

    MedlinePlus

    ... Español Text Size Email Print Share Asthma Medicines: Long-term Control Page Content Article Body Corticosteroids Synthetic ... and sprinkle forms are available for young children. Long-Acting Beta2-Agonists Medications in the beta 2 - ...

  8. Long Term Outcomes after Pediatric Liver Transplantation

    PubMed Central

    2013-01-01

    Long term outcomes after liver transplantation are major determinants of quality of life and of the value of this heroic treatment. As short term outcomes are excellent, our community is turning to take a harder look at long term outcomes. The purpose of this paper is to review these outcomes, and highlight proposed treatments, as well as pressing topics needing to be studied. A systemic review of the English literature was carried in PubMed, covering all papers addressing long term outcomes in pediatric liver transplant from 2000-2013. Late outcomes after pediatric liver transplant affect the liver graft in the form of chronic liver dysfunction. The causes include rejection particularly humoral rejection, but also de novo autoimmune hepatitis, and recurrent disease. The metabolic syndrome is a major factor in long term cardiovascular complication risk. Secondary infections, kidney dysfunction and malignancy remain a reality of those patients. There is growing evidence of late cognitive and executive function delays affecting daily life productivity as well as likely adherence. Finally, despite a good health status, quality of life measures are comparable to those of children with chronic diseases. Long term outcomes are the new frontier in pediatric liver transplantation. Much is needed to improve graft survival, but also to avoid systemic morbidities from long term immunosuppression. Quality of life is a new inclusive measure that will require interventions and innovative approaches respectful not only on the patients but also of their social circle. PMID:24511516

  9. A mechanistic, stochastic, population model of egg production.

    PubMed

    Johnston, S A; Gous, R M

    2007-04-01

    1. A mechanistic, stochastic egg production model is presented. Mean age at first egg may be predicted from the lighting programme applied during rearing, using the Bristol-Reading model (Lewis et al., 2002). 2. Rate of ovulation is determined by an amended version of the mathematical model of the ovulatory cycle, originally proposed by Etches and Schoch (1984). 3. Oviposition times are estimated from ovulation times. 4. Yolk, albumen and shell weights are calculated using allometric functions. 5. The model predicts egg production of a theoretical flock of laying hens for a full laying year, including random occurrences of double-yolked and soft-shelled eggs and internal ovulations.

  10. Demographic stochasticity in small remnant populations of the declining distylous plant Primula veris

    USGS Publications Warehouse

    Kery, M.; Matthies, D.; Schmid, B.

    2003-01-01

    We studied ecological consequences of distyly for the declining perennial plant Primula veris in the Swiss Jura. Distyly favours cross-fertilization and avoids inbreeding, but may lead to pollen limitation and reduced reproduction if morph frequencies deviate from 50 %. Disassortative mating is promoted by the reciprocal position of stigmas and anthers in the two morphs (pin and thrum) and by intramorph incompatibility and should result in equal frequencies of morphs at equilibrium. However, deviations could arise because of demographic stochasticity, the lower intra-morph incompatibility of the pin morph, and niche differentiation between morphs. Demographic stochasticity should result in symmetric deviations from an even morph frequency among populations and in increased deviations with decreasing population size. If crosses between pins occurred, these would only generate pins, and this could result in a pin-bias of morph frequencies in general and in small populations in particular. If the morphs have different niches, morph frequencies should be related to environmental factors, morphs might be spatially segregated, and morphological differences between morphs would be expected. We tested these hypotheses in the declining distylous P. veris. We studied morph frequencies in relation to environmental conditions and population size, spatial segregation in field populations, morphological differences between morphs, and growth responses to nutrient addition. Morph frequencies in 76 populations with 1 - 80000 flowering plants fluctuated symmetrically about 50 %. Deviations from 50 % were much larger in small populations, and sixof the smallest populations had lost one morph altogether. In contrast, morph frequencies were neither related to population size nor to 17 measures of environmental conditions. We found no spatial segregation or morphological differences in the field or in the common garden. The results suggest that demographic stochasticity caused

  11. Long term cultivation of larger benthic Foraminifera

    NASA Astrophysics Data System (ADS)

    Wöger, Julia; Eder, Wolfgang; Kinoshita, Shunichi; Antonino, Briguglio; Carles, Ferrandes-Cañadell; Hohenegger, Johann

    2015-04-01

    Benthic Foraminifera are used in a variety of applications employing numerous different methods, i.e. ecological monitoring, studying the effects of ocean acidification, reconstructing palaeo-bathymetry or investigating palaeo-salinity and palaeo-temperature to name only a few. To refine our understanding of ecological influences on larger benthic foraminiferal biology and to review inferences from field observations, culture experiments have become an indispensable tool. While culture experiments on smaller benthic foraminifera have become increasingly frequent in the past century, reports of the cultivation of symbiont bearing larger Foraminifera are rare. Generally, cultivation experiments can be divided into two groups: Culturing of populations and cultivation of single specimens allowing individual investigation. The latter differ form the former by several restrictions resulting from the need to limit individual motility without abridging microenvironmental conditions in the Foraminiferans artificial habitat, necessary to enable the individual to development as unfettered as possible. In this study we present first experiences and preliminary results of the long-term cultivation of larger benthic Foraminifera conducted at the 'Tropical Biosphere Research Station Sesoko Island, University of the Ryukyus', Japan, trying to reproduce natural conditions as closely as possible. Individuals of three species of larger benthic Foraminifera (Heterostegina depressa, Palaeonummulites venosus and Operculina complanata) have been cultured since April 2014. At the time of the general assembly the cultivation experiments will have been going on for more than one year, with the aim to investigate growth rates, longevities and reproduction strategies for comparison with results statistically inferred from application of the of the 'natural laboratory' method. The most important factor influencing foraminiferal health and development was found to be light intensity and light

  12. Integration of Research with Long-Term Monitoring: Breeding Wood Ducks on the Savannah River Site

    SciTech Connect

    Kennamer, R.A.; Hepp, G.R.

    2000-10-01

    In 1981, long-term monitoring of breeding wood ducks was initiated. Females were marked and recaptured for 15 years and annual population parameters were developed. Precise parameter estimates were possible due to high capture rates. The results contribute to the long-term understanding of wood duck populations.

  13. Long-term outcomes of autoimmune pancreatitis.

    PubMed

    Ikeura, Tsukasa; Miyoshi, Hideaki; Shimatani, Masaaki; Uchida, Kazushige; Takaoka, Makoto; Okazaki, Kazuichi

    2016-09-14

    Autoimmune pancreatitis (AIP) has been considered a favorable-prognosis disease; however, currently, there is limited information on natural course of AIP during long-term follow-up. Recently published studies regarding the long-term outcomes of AIP has demonstrated the developments of pancreatic stone formation, exocrine insufficiency, and endocrine insufficiency are observed in 5%-41%, 34%-82%, and 38%-57% of patients having the disease. Furthermore, the incidence rate of developing pancreatic cancer ranges from 0% to 4.8% during the long-term follow-up. The event of death from AIP-related complications other than accompanying cancer is likely to be rare. During follow-up of AIP patients, careful surveillance for not only relapse of the disease but also development of complications at regular intervals is needed. PMID:27678359

  14. Long-term outcomes of autoimmune pancreatitis

    PubMed Central

    Ikeura, Tsukasa; Miyoshi, Hideaki; Shimatani, Masaaki; Uchida, Kazushige; Takaoka, Makoto; Okazaki, Kazuichi

    2016-01-01

    Autoimmune pancreatitis (AIP) has been considered a favorable-prognosis disease; however, currently, there is limited information on natural course of AIP during long-term follow-up. Recently published studies regarding the long-term outcomes of AIP has demonstrated the developments of pancreatic stone formation, exocrine insufficiency, and endocrine insufficiency are observed in 5%-41%, 34%-82%, and 38%-57% of patients having the disease. Furthermore, the incidence rate of developing pancreatic cancer ranges from 0% to 4.8% during the long-term follow-up. The event of death from AIP-related complications other than accompanying cancer is likely to be rare. During follow-up of AIP patients, careful surveillance for not only relapse of the disease but also development of complications at regular intervals is needed. PMID:27678359

  15. Long-term outcomes of autoimmune pancreatitis

    PubMed Central

    Ikeura, Tsukasa; Miyoshi, Hideaki; Shimatani, Masaaki; Uchida, Kazushige; Takaoka, Makoto; Okazaki, Kazuichi

    2016-01-01

    Autoimmune pancreatitis (AIP) has been considered a favorable-prognosis disease; however, currently, there is limited information on natural course of AIP during long-term follow-up. Recently published studies regarding the long-term outcomes of AIP has demonstrated the developments of pancreatic stone formation, exocrine insufficiency, and endocrine insufficiency are observed in 5%-41%, 34%-82%, and 38%-57% of patients having the disease. Furthermore, the incidence rate of developing pancreatic cancer ranges from 0% to 4.8% during the long-term follow-up. The event of death from AIP-related complications other than accompanying cancer is likely to be rare. During follow-up of AIP patients, careful surveillance for not only relapse of the disease but also development of complications at regular intervals is needed.

  16. Establishing a beachhead: A stochastic population model with an Allee effect applied to species invasion

    USGS Publications Warehouse

    Ackleh, A.S.; Allen, L.J.S.; Carter, J.

    2007-01-01

    We formulated a spatially explicit stochastic population model with an Allee effect in order to explore how invasive species may become established. In our model, we varied the degree of migration between local populations and used an Allee effect with variable birth and death rates. Because of the stochastic component, population sizes below the Allee effect threshold may still have a positive probability for successful invasion. The larger the network of populations, the greater the probability of an invasion occurring when initial population sizes are close to or above the Allee threshold. Furthermore, if migration rates are low, one or more than one patch may be successfully invaded, while if migration rates are high all patches are invaded. ?? 2007 Elsevier Inc. All rights reserved.

  17. Predator-prey model for the self-organization of stochastic oscillators in dual populations

    NASA Astrophysics Data System (ADS)

    Moradi, Sara; Anderson, Johan; Gürcan, Ozgür D.

    2015-12-01

    A predator-prey model of dual populations with stochastic oscillators is presented. A linear cross-coupling between the two populations is introduced following the coupling between the motions of a Wilberforce pendulum in two dimensions: one in the longitudinal and the other in torsional plain. Within each population a Kuramoto-type competition between the phases is assumed. Thus, the synchronization state of the whole system is controlled by these two types of competitions. The results of the numerical simulations show that by adding the linear cross-coupling interactions predator-prey oscillations between the two populations appear, which results in self-regulation of the system by a transfer of synchrony between the two populations. The model represents several important features of the dynamical interplay between the drift wave and zonal flow turbulence in magnetically confined plasmas, and a novel interpretation of the coupled dynamics of drift wave-zonal flow turbulence using synchronization of stochastic oscillator is discussed.

  18. Scenarios for long-term analysis

    SciTech Connect

    Wolbers, Stephen; /Fermilab

    2009-01-01

    Data Preservation and Long-Term Analysis of High Energy Physics (HEP) Experiments data is described and summarized in this talk. The summary covers information presented at the First Workshop on Data Preservation and Long-Term Analysis. Experiments representing e{sup +}e{sup -} collisions (LEP, B Factories and CLEO), ep collisions (H1 and ZEUS), p{bar p} collisions (CDF and D0) and others presented interesting information related to utilizing the large datasets collected over many years at these HEP facilities. Many questions and issues remain to be explored.

  19. Long-term demographic consequences of a seed dispersal disruption

    PubMed Central

    Traveset, Anna; González-Varo, Juan P.; Valido, Alfredo

    2012-01-01

    The loss or decline of vertebrate frugivores can limit the regeneration of plants that depend on them. However, empirical evidence is showing that this is still very scarce, as functionally equivalent species may contribute to maintain the mutualistic interaction. Here, we investigated the long-term consequences of the extinction of frugivorous lizards on the population persistence of a Mediterranean relict shrub Cneorum tricoccon (Cneoraceae). We examined the demographic parameters among 26 insular and mainland populations, which encompass the entire plant distributional range, comparing populations with lizards with those in which these are extinct, but in which alien mammals currently act as seed dispersers. Plant recruitment was found to be higher on island populations with lizards than on those with mammals, and the long-term effects of the native disperser's loss were found in all vital phases of plant regeneration. The study thus gives evidence of the cascading effects of human-induced changes in ecosystems, showing how the disruption of native ecological processes can lead to species regression and, in the long term, even to local extinctions. PMID:22628466

  20. Stochastic demography and population dynamics in the red kangaroo Macropus rufus.

    PubMed

    Jonzén, Niclas; Pople, Tony; Knape, Jonas; Sköld, Martin

    2010-01-01

    1. Many organisms inhabit strongly fluctuating environments but their demography and population dynamics are often analysed using deterministic models and elasticity analysis, where elasticity is defined as the proportional change in population growth rate caused by a proportional change in a vital rate. Deterministic analyses may not necessarily be informative because large variation in a vital rate with a small deterministic elasticity may affect the population growth rate more than a small change in a less variable vital rate having high deterministic elasticity. 2. We analyse a stochastic environment model of the red kangaroo (Macropus rufus), a species inhabiting an environment characterized by unpredictable and highly variable rainfall, and calculate the elasticity of the stochastic growth rate with respect to the mean and variability in vital rates. 3. Juvenile survival is the most variable vital rate but a proportional change in the mean adult survival rate has a much stronger effect on the stochastic growth rate. 4. Even if changes in average rainfall have a larger impact on population growth rate, increased variability in rainfall may still be important also in long-lived species. The elasticity with respect to the standard deviation of rainfall is comparable to the mean elasticities of all vital rates but the survival in age class 3 because increased variation in rainfall affects both the mean and variability of vital rates. 5. Red kangaroos are harvested and, under the current rainfall pattern, an annual harvest fraction of c. 20% would yield a stochastic growth rate about unity. However, if average rainfall drops by more than c. 10%, any level of harvesting may be unsustainable, emphasizing the need for integrating climate change predictions in population management and increase our understanding of how environmental stochasticity translates into population growth rate.

  1. Stochastic Tunneling of Two Mutations in a Population of Cancer Cells

    PubMed Central

    Haeno, Hiroshi; Maruvka, Yosef E.

    2013-01-01

    Cancer initiation, progression, and the emergence of drug resistance are driven by specific genetic and/or epigenetic alterations such as point mutations, structural alterations, DNA methylation and histone modification changes. These alterations may confer advantageous, deleterious or neutral effects to mutated cells. Previous studies showed that cells harboring two particular alterations may arise in a fixed-size population even in the absence of an intermediate state in which cells harboring only the first alteration take over the population; this phenomenon is called stochastic tunneling. Here, we investigated a stochastic Moran model in which two alterations emerge in a cell population of fixed size. We developed a novel approach to comprehensively describe the evolutionary dynamics of stochastic tunneling of two mutations. We considered the scenarios of large mutation rates and various fitness values and validated the accuracy of the mathematical predictions with exact stochastic computer simulations. Our theory is applicable to situations in which two alterations are accumulated in a fixed-size population of binary dividing cells. PMID:23840359

  2. Evolutionary Branching in a Finite Population: Deterministic Branching vs. Stochastic Branching

    PubMed Central

    Wakano, Joe Yuichiro; Iwasa, Yoh

    2013-01-01

    Adaptive dynamics formalism demonstrates that, in a constant environment, a continuous trait may first converge to a singular point followed by spontaneous transition from a unimodal trait distribution into a bimodal one, which is called “evolutionary branching.” Most previous analyses of evolutionary branching have been conducted in an infinitely large population. Here, we study the effect of stochasticity caused by the finiteness of the population size on evolutionary branching. By analyzing the dynamics of trait variance, we obtain the condition for evolutionary branching as the one under which trait variance explodes. Genetic drift reduces the trait variance and causes stochastic fluctuation. In a very small population, evolutionary branching does not occur. In larger populations, evolutionary branching may occur, but it occurs in two different manners: in deterministic branching, branching occurs quickly when the population reaches the singular point, while in stochastic branching, the population stays at singularity for a period before branching out. The conditions for these cases and the mean branching-out times are calculated in terms of population size, mutational effects, and selection intensity and are confirmed by direct computer simulations of the individual-based model. PMID:23105010

  3. Characteristics of Long-Term First Marriages.

    ERIC Educational Resources Information Center

    Fenell, David L.

    1993-01-01

    Investigated characteristics of long-term first marriages (over 20 years). Findings from 147 couples revealed: lifetime commitment to marriage, loyalty to spouse, strong moral values, respect for spouse as best friend, commitment to sexual fidelity, desire to be good parent, faith in God, desire to please and support spouse, good companion to…

  4. Long Term Transfer Effect of Metaphoric Allusion.

    ERIC Educational Resources Information Center

    Hayes, David A.; Mateja, John A.

    A study was conducted to investigate the long term transfer effect of metaphoric allusion used to clarify unfamiliar subject matter. Forty-nine high school students were given unfamiliar prose materials variously augmented by metaphoric allusion. The subjects' immediate performance on a transfer task was compared to their performance on an…

  5. Evaluating Long-Term Disability Insurance Plans.

    ERIC Educational Resources Information Center

    Powell, Jan

    1992-01-01

    This report analyzes the factors involved in reviewing benefits and services of employer-sponsored group long-term disability plans for higher education institutions. Opening sections describe the evolution of disability insurance and its shape today. Further sections looks at the complex nature of "value" within a plan, relationship between plan…

  6. The long term characteristics of greenschist

    NASA Astrophysics Data System (ADS)

    Jang, Bo-An

    2016-04-01

    The greenschist in the Jinping II Hydropower Station in southwest China exhibits continuous creep behaviour because of the geological conditions in the region. This phenomenon illustrates the time-dependent deformation and progressive damage that occurs after excavation. In this study, the responses of greenschist to stress over time were determined in a series of laboratory tests on samples collected from the access tunnel walls at the construction site. The results showed that the greenschist presented time-dependent behaviour under long-term loading. The samples generally experienced two stages: transient creep and steady creep, but no accelerating creep. The periods of transient creep and steady creep increased with increasing stress levels. The long-term strength of the greenschist was identified based on the variation of creep strain and creep rate. The ratio of long-term strength to conventional strength was around 80% and did not vary much with confining pressures. A quantitative method for predicting the failure period of greenschist, based on analysis of the stress-strain curve, is presented and implemented. At a confining pressure of 40 MPa, greenschist was predicted to fail in 5000 days under a stress of 290 MPa and to fail in 85 days under the stress of 320 MPa, indicating that the long-term strength identified by the creep rate and creep strain is a reliable estimate.

  7. LONG TERM HYDROLOGICAL IMPACT ASSESSMENT (LTHIA)

    EPA Science Inventory

    LTHIA is a universal Urban Sprawl analysis tool that is available to all at no charge through the Internet. It estimates impacts on runoff, recharge and nonpoint source pollution resulting from past or proposed land use changes. It gives long-term average annual runoff for a lan...

  8. Long-Term Memory and Learning

    ERIC Educational Resources Information Center

    Crossland, John

    2011-01-01

    The English National Curriculum Programmes of Study emphasise the importance of knowledge, understanding and skills, and teachers are well versed in structuring learning in those terms. Research outcomes into how long-term memory is stored and retrieved provide support for structuring learning in this way. Four further messages are added to the…

  9. Who Recommends Long-Term Care Matters

    ERIC Educational Resources Information Center

    Kane, Robert L.; Bershadsky, Boris; Bershadsky, Julie

    2006-01-01

    Purpose: Making good consumer decisions requires having good information. This study compared long-term-care recommendations among various types of health professionals. Design and Methods: We gave randomly varied scenarios to a convenience national sample of 211 professionals from varying disciplines and work locations. For each scenario, we…

  10. Long-term lysimeter data on evapotranspiration

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Long term crop evapotranspiration (ET) data measured using large weighing lysimeters have only been gathered in a few places in the world, yet are of great importance for ground truthing of many models of plant water use, mesoscale climate, remote sensing estimation of ET, climate change and climate...

  11. Professionalism in Long-Term Care Settings

    ERIC Educational Resources Information Center

    Lubinski, Rosemary

    2006-01-01

    Speech-language pathologists who serve elders in a variety of long-term care settings have a variety of professional skills and responsibilities. Fundamental to quality service is knowledge of aging and communication changes and disorders associated with this process, institutional alternatives, and the changing nature of today's elders in…

  12. Plutonium packaging and long-term storage

    NASA Astrophysics Data System (ADS)

    Lloyd, Jane A.; Wedman, Douglas E.

    2000-07-01

    It has been demonstrated that the Advanced Recovery and Integrated Extraction System (ARIES) packaging line at Los Alamos National Laboratory can successfully package plutonium to meet DOE requirements for safe long-term storage. The ARIES system has just completed the disassembly and conversion of its first cores ("pits") for nuclear weapons.

  13. Long-Term Sequelae of Stroke

    PubMed Central

    Teasell, Robert W.

    1992-01-01

    Scant attention has been paid to the long-term consequences and complications resulting from a stroke. Many stroke survivors go on to develop a variety of medical, musculoskeletal, and psychosocial complications, years after the acute stroke. The family physician is regularly called upon to deal with these problems, but is often hampered by a lack of resources. PMID:21221264

  14. Social evolution and genetic interactions in the short and long term.

    PubMed

    Van Cleve, Jeremy

    2015-08-01

    The evolution of social traits remains one of the most fascinating and feisty topics in evolutionary biology even after half a century of theoretical research. W.D. Hamilton shaped much of the field initially with his 1964 papers that laid out the foundation for understanding the effect of genetic relatedness on the evolution of social behavior. Early theoretical investigations revealed two critical assumptions required for Hamilton's rule to hold in dynamical models: weak selection and additive genetic interactions. However, only recently have analytical approaches from population genetics and evolutionary game theory developed sufficiently so that social evolution can be studied under the joint action of selection, mutation, and genetic drift. We review how these approaches suggest two timescales for evolution under weak mutation: (i) a short-term timescale where evolution occurs between a finite set of alleles, and (ii) a long-term timescale where a continuum of alleles are possible and populations evolve continuously from one monomorphic trait to another. We show how Hamilton's rule emerges from the short-term analysis under additivity and how non-additive genetic interactions can be accounted for more generally. This short-term approach reproduces, synthesizes, and generalizes many previous results including the one-third law from evolutionary game theory and risk dominance from economic game theory. Using the long-term approach, we illustrate how trait evolution can be described with a diffusion equation that is a stochastic analogue of the canonical equation of adaptive dynamics. Peaks in the stationary distribution of the diffusion capture classic notions of convergence stability from evolutionary game theory and generally depend on the additive genetic interactions inherent in Hamilton's rule. Surprisingly, the peaks of the long-term stationary distribution can predict the effects of simple kinds of non-additive interactions. Additionally, the peaks

  15. The Changing Face of Long-Term Care

    PubMed Central

    Vladeck, Bruce C.; Miller, Nancy A.; Clauser, Steven B.

    1993-01-01

    In this article, we present population estimates of individuals with disabilities and discuss the manner in which the composition of this population is changing. We then highlight aspects of service delivery systems that are evolving in response to the changing long-term care (LTC) population. Following a summary of financing issues, we discuss several cross-cutting issues related to the organization of service delivery, quality assurance (QA), and financing. Current and future Health Care Financing Administration (HCFA) research and demonstrations emerging from these issues are then described. PMID:10171815

  16. Relationship between short- and long-term memory and short- and long-term extinction.

    PubMed

    Cammarota, Martín; Bevilaqua, Lia R M; Rossato, Janine I; Ramirez, Maria; Medina, Jorge H; Izquierdo, Iván

    2005-07-01

    Both the acquisition and the extinction of memories leave short- and long-term mnemonic traces. Here, we show that in male Wistar rats, the short-term memory for a step-down inhibitory avoidance task (IA) is resistant to extinction, and that its expression does not influence retrieval or extinction of long-term memory. It has been known for some time that short- and long-term inhibitory avoidance memory involve separate and parallel processes. Here we show that, instead, short-term extinction of IA long-term memory is the first step towards its long-term extinction, and that this link requires functional NMDA receptors and protein synthesis in the CA1 region of the dorsal hippocampus at the time of the first CS-no US presentation.

  17. Long-Term Care Financing: Lessons From France

    PubMed Central

    Doty, Pamela; Nadash, Pamela; Racco, Nathalie

    2015-01-01

    Context An aging population leads to a growing demand for long-term services and supports (LTSS). In 2002, France introduced universal, income-adjusted, public long-term care coverage for adults 60 and older, whereas the United States funds means-tested benefits only. Both countries have private long-term care insurance (LTCI) markets: American policies create alternatives to out-of-pocket spending and protect purchasers from relying on Medicaid. Sales, however, have stagnated, and the market's viability is uncertain. In France, private LTCI supplements public coverage, and sales are growing, although its potential to alleviate the long-term care financing problem is unclear. We explore whether France's very different approach to structuring public and private financing for long-term care could inform the United States’ long-term care financing reform efforts. Methods We consulted insurance experts and conducted a detailed review of public reports, academic studies, and other documents to understand the public and private LTCI systems in France, their advantages and disadvantages, and the factors affecting their development. Findings France provides universal public coverage for paid assistance with functional dependency for people 60 and older. Benefits are steeply income adjusted and amounts are low. Nevertheless, expenditures have exceeded projections, burdening local governments. Private supplemental insurance covers 11% of French, mostly middle-income adults (versus 3% of Americans 18 and older). Whether policyholders will maintain employer-sponsored coverage after retirement is not known. The government's interest in pursuing an explicit public/private partnership has waned under President François Hollande, a centrist socialist, in contrast to the previous center-right leader, President Nicolas Sarkozy, thereby reducing the prospects of a coordinated public/private strategy. Conclusions American private insurers are showing increasing interest in long-term

  18. Random sparse sampling strategy using stochastic simulation and estimation for a population pharmacokinetic study

    PubMed Central

    Huang, Xiao-hui; Wang, Kun; Huang, Ji-han; Xu, Ling; Li, Lu-jin; Sheng, Yu-cheng; Zheng, Qing-shan

    2013-01-01

    The purpose of this study was to use the stochastic simulation and estimation method to evaluate the effects of sample size and the number of samples per individual on the model development and evaluation. The pharmacokinetic parameters and inter- and intra-individual variation were obtained from a population pharmacokinetic model of clinical trials of amlodipine. Stochastic simulation and estimation were performed to evaluate the efficiencies of different sparse sampling scenarios to estimate the compartment model. Simulated data were generated a 1000 times and three candidate models were used to fit the 1000 data sets. Fifty-five kinds of sparse sampling scenarios were investigated and compared. The results showed that, 60 samples with three points and 20 samples with five points are recommended, and the quantitative methodology of stochastic simulation and estimation is valuable for efficiently estimating the compartment model and can be used for other similar model development and evaluation approaches. PMID:24493975

  19. Optimal vaccination in a stochastic epidemic model of two non-interacting populations.

    PubMed

    Yuan, Edwin C; Alderson, David L; Stromberg, Sean; Carlson, Jean M

    2015-01-01

    Developing robust, quantitative methods to optimize resource allocations in response to epidemics has the potential to save lives and minimize health care costs. In this paper, we develop and apply a computationally efficient algorithm that enables us to calculate the complete probability distribution for the final epidemic size in a stochastic Susceptible-Infected-Recovered (SIR) model. Based on these results, we determine the optimal allocations of a limited quantity of vaccine between two non-interacting populations. We compare the stochastic solution to results obtained for the traditional, deterministic SIR model. For intermediate quantities of vaccine, the deterministic model is a poor estimate of the optimal strategy for the more realistic, stochastic case.

  20. Long-term care as part of the continuum.

    PubMed

    McGrail, Kimberlyn

    2011-01-01

    Long-term care (LTC) is but one piece of a continuum of care that stretches from living at home completely independently to the 24-hour supervision and care provided in LTC facilities. People want to stay at home as long as possible and to retain as much independence as they can, and they are often aided in doing so with informal care provided by family and friends. These realities should inform the debates around the construction of the continuum of care. Canada's spending on facility-based long-term care puts us in the middle of the pack among OECD countries; if we consider the whole of continuing care, combining LTC, supportive housing/assisted living and home-based healthcare, Canada stands out as spending the highest proportion (among the 15 countries compared) on facility-based care. Predicting the number of new long-term care beds needed in the future is difficult because of shifting needs and changes in service delivery - new stops on the continuum of care. It is quite possible to organize a system of care that includes a continuum from home-based care to supportive housing and assisted living to LTC that de-emphasizes this last step. The increasing elderly population in Canada will not bring an apocalypse to the healthcare system, but caring for this population will require a redistribution of resources to increase the emphasis on home and community-based services. Our planning for just how many (if any) new long-term care beds are needed and our assessment of reasonable access to those beds need to rest on a vision for the full spectrum of care and attention to the desires of the population we are trying to serve. PMID:21593615

  1. Stochastic recruitment leads to symmetry breaking in foraging populations

    NASA Astrophysics Data System (ADS)

    Biancalani, Tommaso; Dyson, Louise; McKane, Alan

    2014-03-01

    When an ant colony is faced with two identical equidistant food sources, the foraging ants are found to concentrate more on one source than the other. Analogous symmetry-breaking behaviours have been reported in various population systems, (such as queueing or stock market trading) suggesting the existence of a simple universal mechanism. Past studies have neglected the effect of demographic noise and required rather complicated models to qualitatively reproduce this behaviour. I will show how including the effects of demographic noise leads to a radically different conclusion. The symmetry-breaking arises solely due to the process of recruitment and ceases to occur for large population sizes. The latter fact provides a testable prediction for a real system.

  2. Long-term changes in Saturn's troposphere

    SciTech Connect

    Trafton, L.

    1985-09-01

    Attention is given to the results of a long term monitoring study of Saturn's H/sub 2/ quadrupole and CH/sub 4/ band absorptions outside the equatorial zone, over an interval of half a Saturn year that covers most of the perihelion half of Saturn's elliptical orbit (which is approximately bounded by the equinoxes). Marked long term changes are noted in the CH/sub 4/ absorption, accompanied by weakly opposite changes in the H/sub 2/ absorption. Seasonal changes are inferred on the basis of temporal variations in absorption. Spatial measurements have also been made in the 6450 A NH/sub 3/ band since the 1980 equinox. 42 references.

  3. Long-term reinforced fixed provisional restorations.

    PubMed

    Galindo, D; Soltys, J L; Graser, G N

    1998-06-01

    Extensive prosthodontic treatment often requires fabrication of long-term provisional restorations. Numerous materials and techniques have been described for prolonged insertion of interim restorations. This article describes a procedure for fabrication of long-term reinforced heat-processed provisional restorations based on a diagnostic wax-up. Reinforced heat-processed provisional restorations reduced flexure, which minimizes progressive loss of cement and diminished the possibility of recurrent decay. Occlusal stability and vertical dimension were maintained because of greater wear resistance. Occlusion, tooth contours, and pontic design developed in the provisional restoration were duplicated in the definitive restoration. The use of a matrix from a diagnostic wax-up facilitated fabrication of the prosthesis, and made the procedure less time-consuming and more predictable.

  4. The effects of erythropoiesis-stimulating agents on the short-term and long-term survivals in metastatic breast cancer patients receiving chemotherapy: a SEER population-based study.

    PubMed

    Lai, Yinzhi; Ye, Zhong; Civan, Jesse M; Wang, Chun; Cristofanilli, Massimo; Mu, Zhaomei; Austin, Laura; Palazzo, Juan P; Myers, Ronald E; Yang, Hushan

    2015-09-01

    Current clinical guidelines state that the use of erythropoiesis-stimulating agents (ESAs) may be considered to treat chemotherapy-induced anemia in the non-curative setting to alleviate anemia-related symptoms. However, no convincing survival benefit has been demonstrated to support the use of ESAs in these patients. Using the comprehensive data collected in the National Cancer Institute (NCI)-surveillance epidemiology and end results (SEER) and Medicare-linked database, we analyzed the effect of ESA use on the short-term (18-month) and long-term (60-month) survival rates of chemotherapy-treated metastatic breast cancer patients. Confounding variables were adjusted using a propensity score approach. We also analyzed the effects of ESA on the survival of patients receiving trastuzumab, a commonly prescribed targeted therapy agent in treating HER2-positive tumors. Metastatic breast cancer patients who received ESA treatment exhibited similar 60-month survival rate to those without ESA treatment (22.8 vs. 24.9%, p = 0.8). ESA-treated patients had a trend toward better 18-month survival [crude hazard ratio (HR) 0.86, 95% confidence intervals (CI) 0.68-1.09, p = 0.21]. This protective effect during the first 18 months of chemotherapy became marginally significant after adjusting for the propensity of receiving ESAs (HR 0.80, 95% CI 0.63-1.01, p = 0.070). An interaction effect between ESA and trastuzumab on patient survival was noticeable but not statistically significant. ESAs did not negatively affect the long-term survival of metastatic breast cancer patients. Moreover, ESAs improved patients' survival during the first 18 months of chemotherapy treatment. These findings endorse the current clinical guideline. Given the short survival of these patients, the potential short-term beneficial effects of ESAs are clinically meaningful.

  5. [Taiwan long-term care insurance and the evolution of long-term care in Japan].

    PubMed

    Huang, Hui-Wen; Liu, Shu-Hui; Pai, Yu-Chu

    2010-08-01

    The proportion of elderly (65 years of age and older) in Taiwan has exceeded 10% since 2008. With more elderly, the number of patients suffering from dementia and disabilities has also been rapidly increasing. Japan also has been facing increasing demand for long-term care due to an aging society. Prior to 2000, social welfare programs in Japan, working to cope with changing needs, typically provided insufficient services, and geriatric patients were hospitalized unnecessarily, wasting medical resources and causing undue patient hardship. In response, Japan launched its long-term care insurance program in April 2000. Under the program, city, town and village-based organizations should take responsibility for providing care to the elderly in their place of residence. The program significantly improved previous financial shortfalls and long-term care supply and demand has been met by existing social welfare organization resources. In Taiwan, the provision of long-term care by county / city authorities has proven inconsistent, with performance deemed poor after its first decade of long-term care operations. Service was found to be affected by differences in available resources and insufficient long-term care administration. The cultures of Taiwan and Japan are similar. The authors visited the Japan Long-Term Care Insurance Institute in August 2009. Main issues involved in the implementation and evolution of the Japan long-term Care Insurance are reported on in this paper. We hope such may be useful information to those working to develop long-term care programs in Taiwan. PMID:20661859

  6. Coarse-grained analysis of stochastically simulated cell populations with a positive feedback genetic network architecture.

    PubMed

    Aviziotis, I G; Kavousanakis, M E; Bitsanis, I A; Boudouvis, A G

    2015-06-01

    Among the different computational approaches modelling the dynamics of isogenic cell populations, discrete stochastic models can describe with sufficient accuracy the evolution of small size populations. However, for a systematic and efficient study of their long-time behaviour over a wide range of parameter values, the performance of solely direct temporal simulations requires significantly high computational time. In addition, when the dynamics of the cell populations exhibit non-trivial bistable behaviour, such an analysis becomes a prohibitive task, since a large ensemble of initial states need to be tested for the quest of possibly co-existing steady state solutions. In this work, we study cell populations which carry the lac operon network exhibiting solution multiplicity over a wide range of extracellular conditions (inducer concentration). By adopting ideas from the so-called "equation-free" methodology, we perform systems-level analysis, which includes numerical tasks such as the computation of coarse steady state solutions, coarse bifurcation analysis, as well as coarse stability analysis. Dynamically stable and unstable macroscopic (population level) steady state solutions are computed by means of bifurcation analysis utilising short bursts of fine-scale simulations, and the range of bistability is determined for different sizes of cell populations. The results are compared with the deterministic cell population balance model, which is valid for large populations, and we demonstrate the increased effect of stochasticity in small size populations with asymmetric partitioning mechanisms.

  7. Cutaneous oxalosis after long-term hemodialysis.

    PubMed

    Abuelo, J G; Schwartz, S T; Reginato, A J

    1992-07-01

    A 27-year-old woman undergoing long-term hemodialysis developed cutaneous calcifications on her fingers. A skin biopsy specimen showed that the deposits were calcium oxalate. To our knowledge, only one previous article has reported pathologic and crystallographic studies on calcifications of the skin resulting from dialysis oxalosis. We speculate that vitamin C supplements, liberal tea consumption, an increased serum ionized calcium concentration, and the long duration of hemodialysis contributed to the production of these deposits.

  8. Consequences of long-term hyperparathyroidism.

    PubMed

    Graal, M B; Wolffenbuttel, B H

    1998-07-01

    We describe a young woman with long-term untreated hyperparathyroidism with a superimposed vitamin D deficiency and an extremely decreased bone mineral density that was complicated by a vertebral fracture. Despite pretreatment with intravenous pamidronate and short-term vitamin D supplementation, severe and long-standing hypocalcaemia ('hungry bone syndrome') developed after parathyroidectomy. We discuss the consequences of hyperparathyroidism, especially the effects on bone, the complications of parathyroidectomy and the possibilities of preoperative treatment with bisphosphonates.

  9. Long-term consequences of anorexia nervosa.

    PubMed

    Meczekalski, Blazej; Podfigurna-Stopa, Agnieszka; Katulski, Krzysztof

    2013-07-01

    Anorexia nervosa (AN) is a psychiatric disorder that occurs mainly in female adolescents and young women. The obsessive fear of weight gain, critically limited food intake and neuroendocrine aberrations characteristic of AN have both short- and long-term consequences for the reproductive, cardiovascular, gastrointestinal and skeletal systems. Neuroendocrine changes include impairment of gonadotropin releasing-hormone (GnRH) pulsatile secretion and changes in neuropeptide activity at the hypothalamic level, which cause profound hypoestrogenism. AN is related to a decrease in bone mass density, which can lead to osteopenia and osteoporosis and a significant increase in fracture risk in later life. Rates of birth complications and low birth weight may be higher in women with previous AN. The condition is associated with fertility problems, unplanned pregnancies and generally negative attitudes to pregnancy. During pregnancy, women with the condition have higher rates of hyperemesis gravidarum, anaemia and obstetric complications, as well as impaired weight gain and compromised intrauterine foetal growth. It is reported that 80% of AN patients are affected by a cardiac complications such as sinus bradycardia, a prolonged QT interval on electrocardiography, arrythmias, myocardial mass modification and hypotension. A decrease in bone mineral density (BMD) is one of the most important medical consequences of AN. Reduced BMD may subsequently lead to a three- to seven-fold increased risk of spontaneous fractures. Untreated AN is associated with a significant increase in the risk of death. Better detection and sophisticated therapy should prevent the long-term consequences of this disorder. The aims of treatment are not only recovery but also prophylaxis and relief of the long-term effects of this disorder. Further investigations of the long-term disease risk are needed. PMID:23706279

  10. Interest in Long-Term Care among Health Services Administration Students

    ERIC Educational Resources Information Center

    Temple, April; Thompson, Jon M.

    2011-01-01

    The aging of the population has created increased opportunities for health administrators in long-term care. This study consisted of a cross-sectional survey of 68 undergraduate health services administration students to explore factors related to interest in a career in long-term care administration. One third expressed interest working in the…

  11. The international migration of nurses in long-term care.

    PubMed

    Redfoot, Donald L; Houser, Ari N

    2008-01-01

    This article describes five major factors that are affecting patterns of international migration among nurses who work in long-term care settings: DEMOGRAPHIC DRIVERS: The aging of the populations in developed countries and the low to negative growth in the working-age population will increase the demand for international workers to provide long-term care services. GENDER AND RACE: A dual labor market of long-term care workers, increasingly made up of women of color, is becoming internationalized by the employment of migrating nurses from developing countries. CREDENTIALING: The process of credentialing skilled workers creates barriers to entry for migrating nurses and leads to "decredentialing" where registered nurses work as licensed practical nurses or aides. COLONIAL HISTORY AND GEOGRAPHY: The colonial histories of many European countries and the United States have increased migration from former colonies in developing countries to former colonial powers. WORKER RECRUITMENT: Efforts to limit the recruitment of health care workers from some developing countries have had little effect on migration, in part because much of the recruitment comes through informal channels of family and friends.

  12. The coevolution of long-term pair bonds and cooperation.

    PubMed

    Song, Z; Feldman, M W

    2013-05-01

    The evolution of social traits may not only depend on but also change the social structure of the population. In particular, the evolution of pairwise cooperation, such as biparental care, depends on the pair-matching distribution of the population, and the latter often emerges as a collective outcome of individual pair-bonding traits, which are also under selection. Here, we develop an analytical model and individual-based simulations to study the coevolution of long-term pair bonds and cooperation in parental care, where partners play a Snowdrift game in each breeding season. We illustrate that long-term pair bonds may coevolve with cooperation when bonding cost is below a threshold. As long-term pair bonds lead to assortative interactions through pair-matching dynamics, they may promote the prevalence of cooperation. In addition to the pay-off matrix of a single game, the evolutionarily stable equilibrium also depends on bonding cost and accidental divorce rate, and it is determined by a form of balancing selection because the benefit from pair-bond maintenance diminishes as the frequency of cooperators increases. Our findings highlight the importance of ecological factors affecting social bonding cost and stability in understanding the coevolution of social behaviour and social structures, which may lead to the diversity of biological social systems. PMID:23496797

  13. Electrodes for long-term esophageal electrocardiography.

    PubMed

    Niederhauser, Thomas; Haeberlin, Andreas; Marisa, Thanks; Jungo, Michael; Goette, Josef; Jacomet, Marcel; Abacherli, Roger; Vogel, Rolf

    2013-09-01

    The emerging application of long-term and high-quality ECG recording requires alternative electrodes to improve the signal quality and recording capability of surface skin electrodes. The esophageal ECG has the potential to overcome these limitations but necessitates novel recorder and lead designs. The electrode material is of particular interest, since the material has to ensure conflicting requirements like excellent biopotential recording properties and inertness. To this end, novel electrode materials like PEDOT and silver-PDMS as well as established electrode materials such as stainless steel, platinum, gold, iridium oxide, titanium nitride, and glassy carbon were investigated by long-term electrochemical impedance spectroscopy and model-based signal analysis using the derived in vitro interfacial properties in conjunction with a dedicated ECG amplifier. The results of this novel approach show that titanium nitride and iridium oxide featuring microstructured surfaces did not degrade when exposed to artificial acidic saliva. These materials provide low electrode potential drifts and insignificant signal distortion superior to surface skin electrodes making them compatible with accepted standards for ambulatory ECG. They are superior to the noble and polarizable metals such as platinum, silver, and gold that induced more signal distortions and are superior to esophageal stainless steel electrodes that corrode in artificial saliva. The study provides rigorous criteria for the selection of electrode materials for prolonged ECG recording by combining long-term in vitro electrode material properties with ECG signal quality assessment.

  14. Titanium for long-term tritium storage

    SciTech Connect

    Heung, L.K.

    1994-12-01

    Due to the reduction of nuclear weapon stockpile, there will be an excess of tritium returned from the field. The excess tritium needs to be stored for future use, which might be several years away. A safe and cost effective means for long term storage of tritium is needed. Storing tritium in a solid metal tritide is preferred to storing tritium as a gas, because a metal tritide can store tritium in a compact form and the stored tritium will not be released until heat is applied to increase its temperature to several hundred degrees centigrade. Storing tritium as a tritide is safer and more cost effective than as a gas. Several candidate metal hydride materials have been evaluated for long term tritium storage. They include uranium, La-Ni-Al alloys, zirconium and titanium. The criteria used include material cost, radioactivity, stability to air, storage capacity, storage pressure, loading and unloading conditions, and helium retention. Titanium has the best combination of properties and is recommended for long term tritium storage.

  15. Long-term EEG in children.

    PubMed

    Montavont, A; Kaminska, A; Soufflet, C; Taussig, D

    2015-03-01

    Long-term video-EEG corresponds to a recording ranging from 1 to 24 h or even longer. It is indicated in the following situations: diagnosis of epileptic syndromes or unclassified epilepsy, pre-surgical evaluation for drug-resistant epilepsy, follow-up of epilepsy or in cases of paroxysmal symptoms whose etiology remains uncertain. There are some specificities related to paediatric care: a dedicated pediatric unit; continuous monitoring covering at least a full 24-hour period, especially in the context of pre-surgical evaluation; the requirement of presence by the parents, technician or nurse; and stronger attachment of electrodes (cup electrodes), the number of which is adapted to the age of the child. The chosen duration of the monitoring also depends on the frequency of seizures or paroxysmal events. The polygraphy must be adapted to the type and topography of movements. It is essential to have at least an electrocardiography (ECG) channel, respiratory sensor and electromyography (EMG) on both deltoids. There is no age limit for performing long-term video-EEG even in newborns and infants; nevertheless because of scalp fragility, strict surveillance of the baby's skin condition is required. In the specific context of pre-surgical evaluation, long-term video-EEG must record all types of seizures observed in the child. This monitoring is essential in order to develop hypotheses regarding the seizure onset zone, based on electroclinical correlations, which should be adapted to the child's age and the psychomotor development.

  16. Infective endocarditis: determinants of long term outcome

    PubMed Central

    Netzer, R O M; Altwegg, S C; Zollinger, E; Täuber, M; Carrel, T; Seiler, C

    2002-01-01

    Objective: To evaluate predictors of long term prognosis in infective endocarditis. Design: Retrospective cohort study. Setting: Tertiary care centre. Patients: 212 consecutive patients with infective endocarditis between 1980 and 1995 Main outcome measures: Overall and cardiac mortality; event-free survival; and the following events: recurrence, need for late valve surgery, bleeding and embolic complications, cerebral dysfunction, congestive heart failure. Results: During a mean follow up period of 89 months (range 1–244 months), 56% of patients died. In 180 hospital survivors, overall and cardiac mortality amounted to 45% and 24%, respectively. By multivariate analysis, early surgical treatment, infection by streptococci, age < 55 years, absence of congestive heart failure, and > 6 symptoms or signs of endocarditis during active infection were predictive of improved overall long term survival. Independent determinants of event-free survival were infection by streptococci and age < 55 years. Event-free survival was 17% at the end of follow up both in medically–surgically treated patients and in medically treated patients. Conclusions: Long term survival following infective endocarditis is 50% after 10 years and is predicted by early surgical treatment, age < 55 years, lack of congestive heart failure, and the initial presence of more symptoms of endocarditis. PMID:12067947

  17. Short- and Long-Term Outcomes for Extremely Preterm Infants.

    PubMed

    Patel, Ravi Mangal

    2016-02-01

    Prematurity is the leading cause of infant mortality worldwide. In developed countries, extremely preterm infants contribute disproportionately to both neonatal and infant mortality. Survival of this high-risk population has incrementally improved in recent years. Despite these improvements, approximately one in four extremely preterm infants dies during the birth hospitalization. Among those who survive, respiratory and other morbidities are common, although their effect on quality of life is variable. In addition, long-term neurodevelopmental impairment is a large concern for patients, clinicians, and families. However, the interplay of multiple factors contributes to neurodevelopmental impairment, with measures that change over time and outcomes that can be difficult to define and predict. Understanding outcomes of extremely preterm infants can help better counsel families regarding antenatal and postnatal care and guide strategies to improve survival without morbidity. This review summarizes recent evidence to provide an overview into the short- and long-term outcomes for extremely preterm infants.

  18. Sexual selection enables long-term coexistence despite ecological equivalence.

    PubMed

    M'Gonigle, Leithen K; Mazzucco, Rupert; Otto, Sarah P; Dieckmann, Ulf

    2012-04-26

    Empirical data indicate that sexual preferences are critical for maintaining species boundaries, yet theoretical work has suggested that, on their own, they can have only a minimal role in maintaining biodiversity. This is because long-term coexistence within overlapping ranges is thought to be unlikely in the absence of ecological differentiation. Here we challenge this widely held view by generalizing a standard model of sexual selection to include two ubiquitous features of populations with sexual selection: spatial variation in local carrying capacity, and mate-search costs in females. We show that, when these two features are combined, sexual preferences can single-handedly maintain coexistence, even when spatial variation in local carrying capacity is so slight that it might go unnoticed empirically. This theoretical study demonstrates that sexual selection alone can promote the long-term coexistence of ecologically equivalent species with overlapping ranges, and it thus provides a novel explanation for the maintenance of species diversity. PMID:22466286

  19. A Quantitative Analysis of Factors That Influence Participation in Continuing Education among Nurses Employed in Long-Term Care Facilities

    ERIC Educational Resources Information Center

    Murray, Rhoda R.

    2013-01-01

    As the American population ages, the need for more long-term care services will increase. The elderly who are afflicted with a number of chronic illnesses predominantly use long-term care services. By 2020, 12 million older Americans will need long-term care services, and those 65 and older have a 40% chance of entering some type of long-term care…

  20. A Stochastic Model for the Interbreeding of Two Populations Continuously Sharing the Same Habitat.

    PubMed

    Serva, Maurizio

    2015-12-01

    We propose and solve a stochastic mathematical model of general applicability to interbreeding populations which share the same habitat. Resources are limited so that the total population size is fixed by environmental factors. Interbreeding occurs during all the time of coexistence until one of the two population disappears by a random fluctuation. None of the two populations has a selective advantage. We answer the following questions: How long the two populations coexist and how genetically similar they become before the extinction of one of the two? how much the genetic makeup of the surviving population changes by the contribution of the disappearing one? what it is the number of interbreeding events given the observed introgression of genetic material? The model was originally motivated by a paleoanthropological problem concerning the interbreeding of Neanderthals and African modern humans in Middle East which is responsible for the fraction of Neanderthal genes (1-4%) in present Eurasian population. PMID:26585747

  1. Principles of Long-Term Dynamics of Dendritic Spines

    PubMed Central

    Yasumatsu, Nobuaki; Matsuzaki, Masanori; Miyazaki, Takashi; Noguchi, Jun; Kasai, Haruo

    2008-01-01

    Long-term potentiation (LTP) of synapse strength requires enlargement of dendritic spines on cerebral pyramidal neurons. Long-term depression (LTD) is linked to spine shrinkage. Indeed, spines are dynamic structures: they form, change their shapes and volumes or can disappear in the space of hours. Do all such changes result from synaptic activity, or do some changes result from intrinsic processes? How do enlargement and shrinkage of spines relate to elimination and generation of spines, and how do these processes contribute to the stationary distribution of spine volumes? To answer these questions, we recorded the volumes of many individual spines daily for several days using two-photon imaging of CA1 pyramidal neurons in cultured slices of rat hippocampus between postnatal day 17 to 23. With normal synaptic transmission, spines often changed volume or were created or eliminated, thereby showing activity-dependent plasticity. However, we found that spines changed volume even after we blocked synaptic activity, reflecting a native instability of these small structures over the long term. Such “intrinsic fluctuations” showed unique dependence on spine volume. A mathematical model constructed from these data and the theory of random fluctuations explains population behaviors of spines, such as rates of elimination and generation, stationary distribution of volumes and the long-term persistence of large spines. Our study finds that generation and elimination of spines are more prevalent than previously believed, and spine volume shows significant correlation with its age and life expectancy. The population dynamics of spines also predict key psychological features of memory. PMID:19074033

  2. Experimental evidence of population differences in reproductive investment conditional on environmental stochasticity.

    PubMed

    Gauthey, Zoé; Panserat, Stéphane; Elosegi, Arturo; Herman, Alexandre; Tentelier, Cédric; Labonne, Jacques

    2016-01-15

    Environmental stochasticity is expected to shape life histories of species, wherein organisms subjected to strong environmental variation should display adaptive response by being able to tune their reproductive investment. For riverine ecosystems, climate models forecast an increase in the frequency and intensity of extreme events such as floods and droughts. The speed and the mechanisms by which organisms may adapt their reproductive investment are therefore of primary importance to understand how species will cope with such radical environmental changes. In the present study, we sampled spawners from two different populations of wild brown trout, originating from two environments with contrasting levels of flow stochasticity. We placed them in sympatry within an experimental channel during reproductive season. In one modality, water flow was maintained constant, whereas in another modality, water flow was highly variable. Reproductive investment of all individuals was monitored using weight and energetic plasma metabolite variation throughout the reproductive season. Only the populations originating from the most variable environment showed a plastic response to experimental manipulation of water flow, the females being able to reduce their weight variation (from 19.2% to 13.1%) and metabolites variations (from 84.2% to 18.6% for triglycerides for instance) under variable flow conditions. These results imply that mechanisms to cope with environmental stochasticity can differ between populations of the same species, where some populations can be plastic whereas other cannot.

  3. SLUG - stochastically lighting up galaxies - III. A suite of tools for simulated photometry, spectroscopy, and Bayesian inference with stochastic stellar populations

    NASA Astrophysics Data System (ADS)

    Krumholz, Mark R.; Fumagalli, Michele; da Silva, Robert L.; Rendahl, Theodore; Parra, Jonathan

    2015-09-01

    Stellar population synthesis techniques for predicting the observable light emitted by a stellar population have extensive applications in numerous areas of astronomy. However, accurate predictions for small populations of young stars, such as those found in individual star clusters, star-forming dwarf galaxies, and small segments of spiral galaxies, require that the population be treated stochastically. Conversely, accurate deductions of the properties of such objects also require consideration of stochasticity. Here we describe a comprehensive suite of modular, open-source software tools for tackling these related problems. These include the following: a greatly-enhanced version of the SLUG code introduced by da Silva et al., which computes spectra and photometry for stochastically or deterministically sampled stellar populations with nearly arbitrary star formation histories, clustering properties, and initial mass functions; CLOUDY_SLUG, a tool that automatically couples SLUG-computed spectra with the CLOUDY radiative transfer code in order to predict stochastic nebular emission; BAYESPHOT, a general-purpose tool for performing Bayesian inference on the physical properties of stellar systems based on unresolved photometry; and CLUSTER_SLUG and SFR_SLUG, a pair of tools that use BAYESPHOT on a library of SLUG models to compute the mass, age, and extinction of mono-age star clusters, and the star formation rate of galaxies, respectively. The latter two tools make use of an extensive library of pre-computed stellar population models, which are included in the software. The complete package is available at http://www.slugsps.com.

  4. The Stochastic Evolutionary Game for a Population of Biological Networks Under Natural Selection

    PubMed Central

    Chen, Bor-Sen; Ho, Shih-Ju

    2014-01-01

    In this study, a population of evolutionary biological networks is described by a stochastic dynamic system with intrinsic random parameter fluctuations due to genetic variations and external disturbances caused by environmental changes in the evolutionary process. Since information on environmental changes is unavailable and their occurrence is unpredictable, they can be considered as a game player with the potential to destroy phenotypic stability. The biological network needs to develop an evolutionary strategy to improve phenotypic stability as much as possible, so it can be considered as another game player in the evolutionary process, ie, a stochastic Nash game of minimizing the maximum network evolution level caused by the worst environmental disturbances. Based on the nonlinear stochastic evolutionary game strategy, we find that some genetic variations can be used in natural selection to construct negative feedback loops, efficiently improving network robustness. This provides larger genetic robustness as a buffer against neutral genetic variations, as well as larger environmental robustness to resist environmental disturbances and maintain a network phenotypic traits in the evolutionary process. In this situation, the robust phenotypic traits of stochastic biological networks can be more frequently selected by natural selection in evolution. However, if the harbored neutral genetic variations are accumulated to a sufficiently large degree, and environmental disturbances are strong enough that the network robustness can no longer confer enough genetic robustness and environmental robustness, then the phenotype robustness might break down. In this case, a network phenotypic trait may be pushed from one equilibrium point to another, changing the phenotypic trait and starting a new phase of network evolution through the hidden neutral genetic variations harbored in network robustness by adaptive evolution. Further, the proposed evolutionary game is extended to

  5. Stochastic Demography and the Neutral Substitution Rate in Class-Structured Populations

    PubMed Central

    Lehmann, Laurent

    2014-01-01

    The neutral rate of allelic substitution is analyzed for a class-structured population subject to a stationary stochastic demographic process. The substitution rate is shown to be generally equal to the effective mutation rate, and under overlapping generations it can be expressed as the effective mutation rate in newborns when measured in units of average generation time. With uniform mutation rate across classes the substitution rate reduces to the mutation rate. PMID:24594520

  6. The dynamics of income and neighborhood context for population health: do long-term measures of socioeconomic status explain more of the black/white health disparity than single-point-in-time measures?

    PubMed

    Do, D Phuong

    2009-04-01

    Socioeconomic status, though a robust and strong predictor of health, has generally been unable to fully explain the health gap between blacks and whites in the United States. However, at both the individual and neighborhood levels, socioeconomic status is often treated as a static factor with only single-point-in-time measurements. These cross-sectional measures fail to account for possible heterogeneous histories within groups who may share similar characteristics at a given point in time. As such, ignoring the dynamic nature of socioeconomic status may lead to the underestimation of its importance in explaining health and racial health disparities. In this study, I use national longitudinal data to investigate the relationship between neighborhood poverty and respondent-rated health, focusing on whether the addition of a temporal dimension reveals a stronger relationship between neighborhood poverty and health, and a greater explanatory power for the health gap between blacks and whites. Results indicate that long-term neighborhood measures are stronger predictors of health outcomes and explain a greater amount of the black/white health gap than single-point measures.

  7. Long-term EARLINET dust observations

    NASA Astrophysics Data System (ADS)

    Mona, Lucia; Amiridis, Vassilis; Amodeo, Aldo; Binietoglou, Ioannis; D'Amico, Giuseppe; Schwarz, Anja; Papagiannopoulos, Nikolaos; Papayannis, Alexandros; Sicard, Michael; Comeron, Adolfo; Pappalardo, Gelsomina

    2015-04-01

    Systematic observations of Saharan dust events over Europe are performed from May 2000 by EARLINET, the European Aerosol Research LIdar NETwork. EARLINET is a coordinated network of stations that make use of advanced lidar methods for the vertical profiling of aerosols. The backbone of EARLINET network is a common schedule for performing the measurements and the quality assurance of instruments/data. Particular attention is paid to monitoring the Saharan dust intrusions over the European continent. The geographical distribution of the EARLINET stations is particularly appealing for the dust observation, with stations located all around the Mediterranean and in the center of the Mediterranean (Italian stations) where dust intrusions are frequent, and with several stations in the central Europe where dust penetrates occasionally. All aerosol backscatter and extinction profiles related to observations collected during these alerts are grouped in the devoted "Saharan dust" category of the EARLINET database. This category consists of about 4700 files (as of December 2013). Case studies involving several stations around Europe selected from this long-term database have been provided the opportunity to investigate dust modification processes during transport over the continent. More important, the long term EARLINET dust monitoring allows the investigation of the horizontal and vertical extent of dust outbreaks over Europe and the climatological analysis of dust optical intensive and extensive properties at continental scale. This long-term database is also a unique tool for a systematic comparison with dust model outputs and satellite-derived dust products. Because of the relevance for both dust modeling and satellite retrievals improvement, results about desert dust layers extensive properties as a function of season and source regions are investigated and will be presented at the conference. First comparisons with models outputs and CALIPSO dust products will be

  8. Human Behaviour in Long-Term Missions

    NASA Technical Reports Server (NTRS)

    1997-01-01

    In this session, Session WP1, the discussion focuses on the following topics: Psychological Support for International Space Station Mission; Psycho-social Training for Man in Space; Study of the Physiological Adaptation of the Crew During A 135-Day Space Simulation; Interpersonal Relationships in Space Simulation, The Long-Term Bed Rest in Head-Down Tilt Position; Psychological Adaptation in Groups of Varying Sizes and Environments; Deviance Among Expeditioners, Defining the Off-Nominal Act in Space and Polar Field Analogs; Getting Effective Sleep in the Space-Station Environment; Human Sleep and Circadian Rhythms are Altered During Spaceflight; and Methodological Approach to Study of Cosmonauts Errors and Its Instrumental Support.

  9. Long Term Analysis for the BAM device

    NASA Astrophysics Data System (ADS)

    Bonino, D.; Gardiol, D.

    2011-02-01

    Algorithms aimed at the evaluation of critical quantities are based on models with many parameters, which values are estimated from data. The knowledge, with high accuracy, of these values and the control of their temporal evolution are important features. In this work, we focus on the latter subject, and we show a proposed pipeline for the BAM (Basic Angle Monitoring) Long Term Analysis, aimed at the study of the calibration parameters of the BAM device and of the Basic Angle variation, searching for unwanted trends, cyclic features, or other potential unexpected behaviours.

  10. Long-term outcomes in multiple gestations.

    PubMed

    Rand, Larry; Eddleman, Keith A; Stone, Joanne

    2005-06-01

    Children born from a multiple gestation are at increased risk for cerebral palsy, learning disability, and language and neurobehavioral deficits. With the increased incidence of multiple pregnancies and use of assisted reproductive technology (ART), these issues are more commonly affecting parents. Long-term outcomes are a critical part of preconceptual and early pregnancy counseling for parents faced with a multiple gestation or considering ART, and the provider should be well versed on issues surrounding zygosity, gestational age, higher-order multiples, and the effects of options such as multifetal pregnancy reduction. PMID:15922795

  11. Long-Term Wind Power Variability

    SciTech Connect

    Wan, Y. H.

    2012-01-01

    The National Renewable Energy Laboratory started collecting wind power data from large commercial wind power plants (WPPs) in southwest Minnesota with dedicated dataloggers and communication links in the spring of 2000. Over the years, additional WPPs in other areas were added to and removed from the data collection effort. The longest data stream of actual wind plant output is more than 10 years. The resulting data have been used to analyze wind power fluctuations, frequency distribution of changes, the effects of spatial diversity, and wind power ancillary services. This report uses the multi-year wind power data to examine long-term wind power variability.

  12. Long-term effects of sibling incest.

    PubMed

    Daie, N; Witztum, E; Eleff, M

    1989-11-01

    Although sexual abuse of children is recognized as a serious problem, sibling incest has received relatively little attention. A distinction has been made between power-oriented sibling incest and nurturance-oriented incest. The authors review the relevant literature and present four clinical examples. The cases illustrate the broad range of sibling incest and demonstrate its effects, including the long-term consequences for the perpetrator. Lasting difficulties in establishing and maintaining close relationships, especially sexual ones, are prominent features of each case. Without denying the occurrences of benign sex-play between siblings, the authors emphasize exploitation and abuse as pathogenic aspects of sibling incest.

  13. Performance considerations in long-term spaceflight

    NASA Technical Reports Server (NTRS)

    Akins, F. R.

    1979-01-01

    Maintenance of skilled performance during extended space flight is of critical importance to both the health and safety of crew members and to the overall success of mission goals. An examination of long term effects and performance requirements is therefore a factor of immense importance to the planning of future missions. Factors that were investigated include: definition of performance categories to be investigated; methods for assessing and predicting performance levels; in-flight factors which can affect performance; and factors pertinent to the maintenance of skilled performance.

  14. Long-term space flights - personal impressions

    NASA Astrophysics Data System (ADS)

    Polyakov, V. V.

    During a final 4-month stage of a 1-year space flight of cosmonauts Titov and Manarov, a physician, Valery Polyakov was included on a crew for the purpose of evaluating their health, correcting physical status to prepare for the spacecraft reentry and landing operations. The complex program of scientific investigations and experiments performed by the physician included an evaluation of adaptation reactions of the human body at different stages of space mission using clinicophysiological and biochemical methods; testing of alternative regimes of exercise and new countermeasures to prevent an unfavourable effect of long-term weightlessness.

  15. 17 CFR 256.224 - Other long-term debt.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 17 Commodity and Securities Exchanges 3 2011-04-01 2011-04-01 false Other long-term debt. 256.224... COMPANY ACT OF 1935 6. Long-Term Debt § 256.224 Other long-term debt. This account shall include all long-term debt to nonassociates and not subject to current settlement. Note: Subaccounts shall be...

  16. 17 CFR 256.224 - Other long-term debt.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 17 Commodity and Securities Exchanges 3 2010-04-01 2010-04-01 false Other long-term debt. 256.224... COMPANY ACT OF 1935 6. Long-Term Debt § 256.224 Other long-term debt. This account shall include all long-term debt to nonassociates and not subject to current settlement. Note: Subaccounts shall be...

  17. 47 CFR 54.303 - Long term support.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 47 Telecommunication 3 2010-10-01 2010-10-01 false Long term support. 54.303 Section 54.303... SERVICE Universal Service Support for High Cost Areas § 54.303 Long term support. (a) Beginning January 1... shall receive Long Term Support. Beginning July 1, 2004, no carrier shall receive Long Term Support....

  18. 47 CFR 54.303 - Long term support.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 47 Telecommunication 3 2011-10-01 2011-10-01 false Long term support. 54.303 Section 54.303... SERVICE Universal Service Support for High Cost Areas § 54.303 Long term support. (a) Beginning January 1... shall receive Long Term Support. Beginning July 1, 2004, no carrier shall receive Long Term Support....

  19. Toward a comprehensive long term nicotine policy

    PubMed Central

    Gray, N; Henningfield, J; Benowitz, N; Connolly, G; Dresler, C; Fagerstrom, K; Jarvis, M; Boyle, P

    2005-01-01

    Global tobacco deaths are high and rising. Tobacco use is primarily driven by nicotine addiction. Overall tobacco control policy is relatively well agreed upon but a long term nicotine policy has been less well considered and requires further debate. Reaching consensus is important because a nicotine policy is integral to the target of reducing tobacco caused disease, and the contentious issues need to be resolved before the necessary political changes can be sought. A long term and comprehensive nicotine policy is proposed here. It envisages both reducing the attractiveness and addictiveness of existing tobacco based nicotine delivery systems as well as providing alternative sources of acceptable clean nicotine as competition for tobacco. Clean nicotine is defined as nicotine free enough of tobacco toxicants to pass regulatory approval. A three phase policy is proposed. The initial phase requires regulatory capture of cigarette and smoke constituents liberalising the market for clean nicotine; regulating all nicotine sources from the same agency; and research into nicotine absorption and the role of tobacco additives in this process. The second phase anticipates clean nicotine overtaking tobacco as the primary source of the drug (facilitated by use of regulatory and taxation measures); simplification of tobacco products by limitation of additives which make tobacco attractive and easier to smoke (but tobacco would still be able to provide a satisfying dose of nicotine). The third phase includes a progressive reduction in the nicotine content of cigarettes, with clean nicotine freely available to take the place of tobacco as society's main nicotine source. PMID:15923465

  20. Long term changes in the polar vortices

    NASA Astrophysics Data System (ADS)

    Braathen, Geir O.

    2015-04-01

    As the amount of halogens in the stratosphere is slowly declining and the ozone layer slowly recovers it is of interest to see how the meteorological conditions in the vortex develop over the long term since such changes might alter the foreseen ozone recovery. In conjunction with the publication of the WMO Antarctic and Arctic Ozone Bulletins, WMO has acquired the ERA Interim global reanalysis data set for several meteorological parameters. This data set goes from 1979 - present. These long time series of data can be used for several useful studies of the long term development of the polar vortices. Several "environmental indicators" for vortex change have been calculated, and a climatology, as well as trends, for these parameters will be presented. These indicators can act as yardsticks and will be useful for understanding past and future changes in the polar vortices and how these changes affect polar ozone depletion. Examples of indicators are: vortex mean temperature, vortex minimum temperature, vortex mean PV, vortex "importance" (PV*area), vortex break-up time, mean and maximum wind speed. Data for both the north and south polar vortices have been analysed at several isentropic levels from 350 to 850 K. A possible link between changes in PV and sudden stratospheric warmings will be investigated, and the results presented.

  1. Long-term anticoagulation. Indications and management.

    PubMed Central

    Stults, B M; Dere, W H; Caine, T H

    1989-01-01

    Each year half a million persons in the United States receive long-term anticoagulant therapy to prevent venous and arterial thromboembolism. Unfortunately, the relative benefits and risks of anticoagulant therapy have not been adequately quantified for many thromboembolic disorders, and the decisions as to whether, for how long, and how intensely to administer anticoagulation are often complex and controversial. Several expert panels have published recommendations for anticoagulant therapy for different thromboembolic disorders; the primary area of disagreement among these panels concerns the optimal intensity of anticoagulation. Recent research and analytic reviews have helped to clarify both the risk factors for and the appropriate diagnostic evaluation of anticoagulant-induced hemorrhage. Clinicians must be aware of the nonhemorrhagic complications of anticoagulant therapy, particularly during pregnancy. The administration of anticoagulants is difficult both in relation to dosing and long-term monitoring. Knowledge of the pharmacology of the anticoagulants, an organized approach to ongoing monitoring, and thorough patient education may facilitate the safe and effective use of these drugs. PMID:2686173

  2. Long-term outcome in personality disorders.

    PubMed

    Stone, M H

    1993-03-01

    Personality disorders meeting DSM or ICD criteria represent the severe end of the broad spectrum of personality configurations involving maladaptive traits. The literature regarding long-term outcome of personality disorders is sparse. Most attention is devoted to formerly institutionalised patients with borderline, antisocial, or schizotypal disorders. Borderline patients at 10-25-year follow-up have a wide range of outcomes, from clinical recovery (50-60%) to suicide (3-9%). Certain factors (e.g. artistic talent) conduce to higher recovery rates, others (e.g. parental cruelty) to lower rates. Schizoid and schizotypal patients tend to remain isolated, and to lead marginal lives. The long-term outcome in antisocial persons is bleak if psychopathic traits are prominent. Personality traits and their corresponding disorders are egosyntonic, harden into habit, and are both slow to change and hard to modify. There is no one treatment of choice. Psychoanalysis and related methods work best within the anxious/inhibited group; cognitive/behavioural techniques are well suited to the disorders requiring limit setting and the amelioration of maladaptive habits. PMID:8453424

  3. Long term perfusion system supporting adipogenesis.

    PubMed

    Abbott, Rosalyn D; Raja, Waseem K; Wang, Rebecca Y; Stinson, Jordan A; Glettig, Dean L; Burke, Kelly A; Kaplan, David L

    2015-08-01

    Adipose tissue engineered models are needed to enhance our understanding of disease mechanisms and for soft tissue regenerative strategies. Perfusion systems generate more physiologically relevant and sustainable adipose tissue models, however adipocytes have unique properties that make culturing them in a perfusion environment challenging. In this paper we describe the methods involved in the development of two perfusion culture systems (2D and 3D) to test their applicability for long term in vitro adipogenic cultures. It was hypothesized that a silk protein biomaterial scaffold would provide a 3D framework, in combination with perfusion flow, to generate a more physiologically relevant sustainable adipose tissue engineered model than 2D cell culture. Consistent with other studies evaluating 2D and 3D culture systems for adipogenesis we found that both systems successfully model adipogenesis, however 3D culture systems were more robust, providing the mechanical structure required to contain the large, fragile adipocytes that were lost in 2D perfused culture systems. 3D perfusion also stimulated greater lipogenesis and lipolysis and resulted in decreased secretion of LDH compared to 2D perfusion. Regardless of culture configuration (2D or 3D) greater glycerol was secreted with the increased nutritional supply provided by perfusion of fresh media. These results are promising for adipose tissue engineering applications including long term cultures for studying disease mechanisms and regenerative approaches, where both acute (days to weeks) and chronic (weeks to months) cultivation are critical for useful insight. PMID:25843606

  4. Long Term Changes in the Polar Vortices

    NASA Astrophysics Data System (ADS)

    Braathen, Geir O.

    2016-04-01

    As the amount of halogens in the stratosphere is slowly declining and the ozone layer slowly recovers it is of interest to see how the meteorological conditions in the vortex develop over the long term since such changes might alter the foreseen ozone recovery. In conjunction with the publication of the WMO Antarctic and Arctic Ozone Bulletins, WMO has acquired the ERA Interim global reanalysis data set for several meteorological parameters. This data set goes from 1979 - present. These long time series of data can be used for several useful studies of the long term development of the polar vortices. Several "environmental indicators" for vortex change have been calculated, and a climatology, as well as trends, for these parameters will be presented. These indicators can act as yardsticks and will be useful for understanding past and future changes in the polar vortices and how these changes affect polar ozone depletion. Examples of indicators are: vortex mean temperature, vortex minimum temperature, vortex mean PV, vortex "importance" (PV*area), vortex break-up time, mean and maximum wind speed. Data for both the north and south polar vortices have been analysed at several isentropic levels from 350 to 850 K. A possible link between changes in PV and sudden stratospheric warmings will be investigated, and the results presented. The unusual meteorological conditions of the 2015 south polar vortex and the 2010/11 and 2015/16 north polar vortices will be compared to other recent years.

  5. Long term perfusion system supporting adipogenesis

    PubMed Central

    Abbott, Rosalyn D.; Raja, Waseem K.; Wang, Rebecca Y.; Stinson, Jordan A.; Glettig, Dean L.; Burke, Kelly A.; Kaplan, David L.

    2015-01-01

    Adipose tissue engineered models are needed to enhance our understanding of disease mechanisms and for soft tissue regenerative strategies. Perfusion systems generate more physiologically relevant and sustainable adipose tissue models, however adipocytes have unique properties that make culturing them in a perfusion environment challenging. In this paper we describe the methods involved in the development of two perfusion culture systems (2D and 3D) to test their applicability for long term in vitro adipogenic cultures. It was hypothesized that a silk protein biomaterial scaffold would provide a 3D framework, in combination with perfusion flow, to generate a more physiologically relevant sustainable adipose tissue engineered model than 2D cell culture. Consistent with other studies evaluating 2D and 3D culture systems for adipogenesis we found that both systems successfully model adipogensis, however 3D culture systems were more robust, providing the mechanical structure required to contain the large, fragile adipocytes that were lost in 2D perfused culture systems. 3D perfusion also stimulated greater lipogenesis and lipolysis and resulted in decreased secretion of LDH compared to 2D perfusion. Regardless of culture configuration (2D or 3D) greater glycerol was secreted with the increased nutritional supply provided by perfusion of fresh media. These results are promising for adipose tissue engineering applications including long term cultures for studying disease mechanisms and regenerative approaches, where both acute (days to weeks) and chronic (weeks to months) cultivation are critical for useful insight. PMID:25843606

  6. Toward a comprehensive long term nicotine policy.

    PubMed

    Gray, N; Henningfield, J E; Benowitz, N L; Connolly, G N; Dresler, C; Fagerstrom, K; Jarvis, M J; Boyle, P

    2005-06-01

    Global tobacco deaths are high and rising. Tobacco use is primarily driven by nicotine addiction. Overall tobacco control policy is relatively well agreed upon but a long term nicotine policy has been less well considered and requires further debate. Reaching consensus is important because a nicotine policy is integral to the target of reducing tobacco caused disease, and the contentious issues need to be resolved before the necessary political changes can be sought. A long term and comprehensive nicotine policy is proposed here. It envisages both reducing the attractiveness and addictiveness of existing tobacco based nicotine delivery systems as well as providing alternative sources of acceptable clean nicotine as competition for tobacco. Clean nicotine is defined as nicotine free enough of tobacco toxicants to pass regulatory approval. A three phase policy is proposed. The initial phase requires regulatory capture of cigarette and smoke constituents liberalising the market for clean nicotine; regulating all nicotine sources from the same agency; and research into nicotine absorption and the role of tobacco additives in this process. The second phase anticipates clean nicotine overtaking tobacco as the primary source of the drug (facilitated by use of regulatory and taxation measures); simplification of tobacco products by limitation of additives which make tobacco attractive and easier to smoke (but tobacco would still be able to provide a satisfying dose of nicotine). The third phase includes a progressive reduction in the nicotine content of cigarettes, with clean nicotine freely available to take the place of tobacco as society's main nicotine source. PMID:15923465

  7. Long-term Trend of Sunspot Numbers

    NASA Astrophysics Data System (ADS)

    Gao, P. X.

    2016-10-01

    Using the Hilbert–Huang Transform method, we investigate the long-term trend of yearly mean total sunspot numbers in the time interval of 1700–2015, which come from the World Data Center—the sunspot Index and long-term solar observations. The main findings of this study are summarized below. (1) From the adaptive trend, which is extracted from the yearly mean total sunspot numbers, we can find that the value gradually increases during the time period 1700–1975, then decreases gradually from 1975 to 2015. (2) The Centennial Gleissberg Cycle is extracted from the yearly mean total sunspot numbers and confirms that a new grand minimum is in progress; the Dalton Minimum, the Gleissberg Minimum, and low level of solar activity during solar cycle 24 (the part of the new grand minimum) all can be understood as minima of the Centennial Gleissberg Cycle. (3) Based on the adaptive (overall) trend, and the 100-year and longer timescale trend of yearly mean total sunspot numbers, we can infer that the level of solar activity during the new grand minimum may be close to that during the Gleissberg Minimum, slightly higher than that during the Dalton Minimum, and significantly higher than that during the Maunder Minimum. Our results do not support the suggestion that a new grand minimum, somewhat resembling the Maunder Minimum, is in progress.

  8. Long term perfusion system supporting adipogenesis.

    PubMed

    Abbott, Rosalyn D; Raja, Waseem K; Wang, Rebecca Y; Stinson, Jordan A; Glettig, Dean L; Burke, Kelly A; Kaplan, David L

    2015-08-01

    Adipose tissue engineered models are needed to enhance our understanding of disease mechanisms and for soft tissue regenerative strategies. Perfusion systems generate more physiologically relevant and sustainable adipose tissue models, however adipocytes have unique properties that make culturing them in a perfusion environment challenging. In this paper we describe the methods involved in the development of two perfusion culture systems (2D and 3D) to test their applicability for long term in vitro adipogenic cultures. It was hypothesized that a silk protein biomaterial scaffold would provide a 3D framework, in combination with perfusion flow, to generate a more physiologically relevant sustainable adipose tissue engineered model than 2D cell culture. Consistent with other studies evaluating 2D and 3D culture systems for adipogenesis we found that both systems successfully model adipogenesis, however 3D culture systems were more robust, providing the mechanical structure required to contain the large, fragile adipocytes that were lost in 2D perfused culture systems. 3D perfusion also stimulated greater lipogenesis and lipolysis and resulted in decreased secretion of LDH compared to 2D perfusion. Regardless of culture configuration (2D or 3D) greater glycerol was secreted with the increased nutritional supply provided by perfusion of fresh media. These results are promising for adipose tissue engineering applications including long term cultures for studying disease mechanisms and regenerative approaches, where both acute (days to weeks) and chronic (weeks to months) cultivation are critical for useful insight.

  9. Are breast conservation and mastectomy equally effective in the treatment of young women with early breast cancer? Long-term results of a population-based cohort of 1,451 patients aged ≤ 40 years.

    PubMed

    van der Sangen, Maurice J C; van de Wiel, Fenneke M M; Poortmans, Philip M P; Tjan-Heijnen, Vivianne C G; Nieuwenhuijzen, Grard A P; Roumen, Rudi M H; Ernst, Miranda F; Tutein Nolthenius-Puylaert, M Cathelijne B J E; Voogd, Adri C

    2011-05-01

    To compare the effectiveness of breast-conserving therapy (BCT) and mastectomy, all women aged ≤ 40 years, treated for early-stage breast cancer in the southern part of the Netherlands between 1988 and 2005, were identified. A total of 562 patients underwent mastectomy and 889 patients received BCT. During follow-up, 23 patients treated with mastectomy and 135 patients treated with BCT developed a local relapse without previous or simultaneous evidence of distant disease. The local relapse risk for patients treated with mastectomy was 4.4% (95% confidence interval (CI) 2.4-6.4) at 5 years and reached a plateau after 6 years at 6.0% (95% CI 3.5-8.5). After BCT, the 5-, 10- and 15-year risks were 8.3% (95% CI 6.3-10.5), 18.4% (95% CI 15.0-21.8) and 28.2% (95% CI 23.0-33.4), respectively (P < 0.0001). Adjuvant systemic therapy following BCT reduced the 15-year local relapse risk from 32.9% (95% CI 26.7-39.1) to 16.1% (95% CI 9.1-23.1), (P = 0.0007). In conclusion, local tumor control in young patients with early-stage breast cancer is worse after BCT than after mastectomy. Adjuvant systemic therapy significantly improves local control following BCT and also for that reason it should be considered for most patients ≤ 40 years. Long-term follow-up is highly recommended for young patients after BCT, because even with systemic treatment an annual risk of local relapse of 1% remains up to 15 years after treatment.

  10. Star Cluster Properties in Two LEGUS Galaxies Computed with Stochastic Stellar Population Synthesis Models

    NASA Astrophysics Data System (ADS)

    Krumholz, Mark R.; Adamo, Angela; Fumagalli, Michele; Wofford, Aida; Calzetti, Daniela; Lee, Janice C.; Whitmore, Bradley C.; Bright, Stacey N.; Grasha, Kathryn; Gouliermis, Dimitrios A.; Kim, Hwihyun; Nair, Preethi; Ryon, Jenna E.; Smith, Linda J.; Thilker, David; Ubeda, Leonardo; Zackrisson, Erik

    2015-10-01

    We investigate a novel Bayesian analysis method, based on the Stochastically Lighting Up Galaxies (slug) code, to derive the masses, ages, and extinctions of star clusters from integrated light photometry. Unlike many analysis methods, slug correctly accounts for incomplete initial mass function (IMF) sampling, and returns full posterior probability distributions rather than simply probability maxima. We apply our technique to 621 visually confirmed clusters in two nearby galaxies, NGC 628 and NGC 7793, that are part of the Legacy Extragalactic UV Survey (LEGUS). LEGUS provides Hubble Space Telescope photometry in the NUV, U, B, V, and I bands. We analyze the sensitivity of the derived cluster properties to choices of prior probability distribution, evolutionary tracks, IMF, metallicity, treatment of nebular emission, and extinction curve. We find that slug's results for individual clusters are insensitive to most of these choices, but that the posterior probability distributions we derive are often quite broad, and sometimes multi-peaked and quite sensitive to the choice of priors. In contrast, the properties of the cluster population as a whole are relatively robust against all of these choices. We also compare our results from slug to those derived with a conventional non-stochastic fitting code, Yggdrasil. We show that slug's stochastic models are generally a better fit to the observations than the deterministic ones used by Yggdrasil. However, the overall properties of the cluster populations recovered by both codes are qualitatively similar.

  11. STAR CLUSTER PROPERTIES IN TWO LEGUS GALAXIES COMPUTED WITH STOCHASTIC STELLAR POPULATION SYNTHESIS MODELS

    SciTech Connect

    Krumholz, Mark R.; Adamo, Angela; Fumagalli, Michele; Wofford, Aida; Calzetti, Daniela; Grasha, Kathryn; Lee, Janice C.; Whitmore, Bradley C.; Bright, Stacey N.; Ubeda, Leonardo; Gouliermis, Dimitrios A.; Kim, Hwihyun; Nair, Preethi; Ryon, Jenna E.; Smith, Linda J.; Zackrisson, Erik E-mail: adamo@astro.su.se

    2015-10-20

    We investigate a novel Bayesian analysis method, based on the Stochastically Lighting Up Galaxies (slug) code, to derive the masses, ages, and extinctions of star clusters from integrated light photometry. Unlike many analysis methods, slug correctly accounts for incomplete initial mass function (IMF) sampling, and returns full posterior probability distributions rather than simply probability maxima. We apply our technique to 621 visually confirmed clusters in two nearby galaxies, NGC 628 and NGC 7793, that are part of the Legacy Extragalactic UV Survey (LEGUS). LEGUS provides Hubble Space Telescope photometry in the NUV, U, B, V, and I bands. We analyze the sensitivity of the derived cluster properties to choices of prior probability distribution, evolutionary tracks, IMF, metallicity, treatment of nebular emission, and extinction curve. We find that slug's results for individual clusters are insensitive to most of these choices, but that the posterior probability distributions we derive are often quite broad, and sometimes multi-peaked and quite sensitive to the choice of priors. In contrast, the properties of the cluster population as a whole are relatively robust against all of these choices. We also compare our results from slug to those derived with a conventional non-stochastic fitting code, Yggdrasil. We show that slug's stochastic models are generally a better fit to the observations than the deterministic ones used by Yggdrasil. However, the overall properties of the cluster populations recovered by both codes are qualitatively similar.

  12. Predator-prey model for the self-organization of stochastic oscillators in dual populations

    NASA Astrophysics Data System (ADS)

    Moradi, Sara; Anderson, Johan; Gürcan, Ozgur D.

    A predator-prey model of dual populations with stochastic oscillators is presented. A linear cross-coupling between the two populations is introduced that follows the coupling between the motions of a Wilberforce pendulum in two dimensions: one in the longitudinal and the other in torsional plain. Within each population a Kuramoto type competition between the phases is assumed. Thus, the synchronization state of the whole system is controlled by these two types of competitions. The results of the numerical simulations show that by adding the linear cross-coupling interactions predator-prey oscillations between the two populations appear which results in self-regulation of the system by a transfer of synchrony between the two populations. The model represents several important features of the dynamical interplay between the drift wave and zonal flow turbulence in magnetically confined plasmas, and a novel interpretation of the coupled dynamics of drift wave-zonal flow turbulence using synchronization of stochastic oscillator is discussed. Sara Moradi has benefited from a mobility grant funded by the Belgian Federal Science Policy Office and the MSCA of the European Commission (FP7-PEOPLE-COFUND-2008 nº 246540).

  13. Predator-prey model for the self-organization of stochastic oscillators in dual populations.

    PubMed

    Moradi, Sara; Anderson, Johan; Gürcan, Ozgür D

    2015-12-01

    A predator-prey model of dual populations with stochastic oscillators is presented. A linear cross-coupling between the two populations is introduced following the coupling between the motions of a Wilberforce pendulum in two dimensions: one in the longitudinal and the other in torsional plain. Within each population a Kuramoto-type competition between the phases is assumed. Thus, the synchronization state of the whole system is controlled by these two types of competitions. The results of the numerical simulations show that by adding the linear cross-coupling interactions predator-prey oscillations between the two populations appear, which results in self-regulation of the system by a transfer of synchrony between the two populations. The model represents several important features of the dynamical interplay between the drift wave and zonal flow turbulence in magnetically confined plasmas, and a novel interpretation of the coupled dynamics of drift wave-zonal flow turbulence using synchronization of stochastic oscillator is discussed. PMID:26764797

  14. Long-term performance of filtration layer

    NASA Astrophysics Data System (ADS)

    Radfar, A.; Rockaway, T. D.

    2013-12-01

    Permeable pavements are commonly employed to capture and divert stormwater before it enters the stormwater or sewer conveyance systems. During a storm event, runoff water passes through the permeable pavement surface, enters a storage gallery and finally exfiltrates into the surrounding soil. Thus, the ability of the system to store an appropriate volume of runoff water is an important consideration for stormwater control design. Traditionally, crushed stone or other porous material has been used to provide the necessary interstitial void space to store the runoff water. Unfortunately, over time the available void space within the storage gallery is reduced due to settlement, biological growth and sediment accumulation. This gradual reduction in void space reduces the long-term effectiveness of these stormwater controls by limiting its ability to store and pass runoff water. This study examined the long-term performance of the storage gallery layer with respect to its ability to both store and pass runoff water. As the porosity within the storage gallery decreased, it was anticipated that volumetric water content within the gallery would increase and that time necessary to drain the gallery would increase as well. The effects of the gallery porosity were assessed over a one-year study using both laboratory experimentation and monitoring data from naturally occurring rain events. Changes in gallery porosity were first assessed by correlating monitoring piezometer data with surface infiltration testing; building a relation between know volume of poured water being used for the test and the associated pressure head at the base of the gallery. As a known volume of water enters the system, volume change in the gallery directly correlate to increases in pressure head. Second, the time required for water to permeate through pavers and gallery layer to trigger the TDRs in the filtration layer and the time to drain it from the crushed stone were calculated and compared by

  15. Managing soils for long-term productivity

    PubMed Central

    Syers, J. K.

    1997-01-01

    Meeting the goal of long-term agricultural productivity requires that soil degradation be halted and reversed. Soil fertility decline is a key factor in soil degradation and is probably the major cause of declining crop yields. There is evidence that the contribution of declining soil fertility to soil degradation has been underestimated.
    Sensitivity to soil degradation is implicit in the assessment of the sustainability of land management practices, with wide recognition of the fact that soils vary in their ability to resist change and recover subsequent to stress. The concept of resilience in relation to sustainability requires further elaboration and evaluation.
    In the context of soil degradation, a decline in soil fertility is primarily interpreted as the depletion of organic matter and plant nutrients. Despite a higher turnover rate of organic matter in the tropics there is no intrinsic difference between the organic matter content of soils from tropical and temperate regions. The level of organic matter in a soil is closely related to the above and below ground inputs. In the absence of adequate organic material inputs and where cultivation is continuous, soil organic matter declines progressively. Maintaining the quantity and quality of soil organic matter should be a guiding principle in developing management practices.
    Soil microbial biomass serves as an important reservoir of nitrogen (N), phosphorus (P) and sulphur (S), and regulates the cycling of organic matter and nutrients. Because of its high turnover rate, microbial biomass reacts quickly to changes in management and is a sensitive indicator for monitoring and predicting changes in soil organic matter. Modelling techniques have been reasonably successful in predicting changes in soil organic matter with different organic material inputs, but there is little information from the tropics.
    Nutrient depletion through harvested crop components and residue removal, and by leaching and soil

  16. 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

  17. Long-term global nuclear energy and fuel cycle strategies

    SciTech Connect

    Krakowski, R.A.

    1997-09-24

    The Global Nuclear Vision Project is examining, using scenario building techniques, a range of long-term nuclear energy futures. The exploration and assessment of optimal nuclear fuel-cycle and material strategies is a