scholarly journals Evolutionary Mechanisms of Persistence and Diversification of a Calicivirus within Endemically Infected Natural Host Populations

2006 ◽  
Vol 81 (4) ◽  
pp. 1961-1971 ◽  
Author(s):  
Karen P. Coyne ◽  
Rosalind M. Gaskell ◽  
Susan Dawson ◽  
Carol J. Porter ◽  
Alan D. Radford
Keyword(s):  
Host Population ◽  
Evolutionary Mechanisms ◽  
Term Survival ◽  
Variable Regions ◽  
Individual Level ◽  
Relative Contribution ◽  
Different Strains ◽  
The Individual ◽  
Mechanisms Of Persistence

ABSTRACT In order to understand the evolutionary mechanisms of persistence and diversification within the Caliciviridae, we have been exploiting endemic infection of feline calicivirus within five geographically distinct household groups of cats. By sequencing immunodominant and variable regions of the capsid gene, we identified the relative contribution of the different evolutionary processes employed by the virus to ensure its long-term survival in the host population. Such strategies included progressive evolution of a given variant of a strain through mutation accumulation within an individual, sequential reinfection with either a variant of the same strain or with a different strain, and mixed infection. Recombination between different strains in this study has been reported in detail elsewhere (K. P. Coyne et al., J. Gen. Virol. 87:921-926, 2006). Here, we provide evidence to suggest that true long-term persistent infection in individuals is relatively rare, with the majority of apparent viral carriers undergoing a combination of progressive evolution and cyclical reinfection. Progressive evolution at the individual level and variant reinfection at both the individual and population levels were associated with positive selection. Two measures of evolution rate were determined; for a virus progressively evolving within an individual (1.32 × 10−2 to 2.64 × 10−2 substitutions per nucleotide per year, i.e., no transmission) and for a strain circulating within a population (3.84 × 10−2 to 4.56 × 10−2 substitutions per nucleotide per year, i.e., including transmission). Reiteration of both progressive evolution and variant reinfection appeared to lead to a gradual increase in the diversity of a given strain of virus, both in the individual and in the population, until eventually new strains emerged.

scholarly journals Does workplace social capital protect against long-term sickness absence? Linking workplace aggregated social capital to sickness absence registry data

2017 ◽  
Vol 46 (3) ◽  
pp. 290-296 ◽  
Author(s):  
Anne-Sophie K. Hansen ◽  
Ida E. H. Madsen ◽  
Sannie Vester Thorsen ◽  
Ole Melkevik ◽  
Jakob Bue Bjørner ◽  
...  
Keyword(s):  
Social Capital ◽  
Private Sector ◽  
Sickness Absence ◽  
Collective Good ◽  
Standard Deviation Increase ◽  
Individual Level ◽  
The Individual ◽  
Adjusted Model ◽  
Workplace Social Capital

Aims: Most previous prospective studies have examined workplace social capital as a resource of the individual. However, literature suggests that social capital is a collective good. In the present study we examined whether a high level of workplace aggregated social capital (WASC) predicts a decreased risk of individual-level long-term sickness absence (LTSA) in Danish private sector employees. Methods: A sample of 2043 employees (aged 18–64 years, 38.5% women) from 260 Danish private-sector companies filled in a questionnaire on workplace social capital and covariates. WASC was calculated by assigning the company-averaged social capital score to all employees of each company. We derived LTSA, defined as sickness absence of more than three weeks, from a national register. We examined if WASC predicted employee LTSA using multilevel survival analyses, while excluding participants with LTSA in the three months preceding baseline. Results: We found no statistically significant association in any of the analyses. The hazard ratio for LTSA in the fully adjusted model was 0.93 (95% CI 0.77–1.13) per one standard deviation increase in WASC. When using WASC as a categorical exposure we found a statistically non-significant tendency towards a decreased risk of LTSA in employees with medium WASC (fully adjusted model: HR 0.78 (95% CI 0.48–1.27)). Post hoc analyses with workplace social capital as a resource of the individual showed similar results. Conclusions: WASC did not predict LTSA in this sample of Danish private-sector employees.

Suitability of a young deciduous-dominated forest for American marten and the effects of forest removal

2004 ◽  
Vol 82 (3) ◽  
pp. 423-435 ◽  
Author(s):  
Kim G Poole ◽  
Aswea D Porter ◽  
Andrew de Vries ◽  
Chris Maundrell ◽  
Scott D Grindal ◽  
...  
Keyword(s):  
Populus Tremuloides ◽  
Forest Cover ◽  
Agricultural Land ◽  
Prey Availability ◽  
Population Level ◽  
Home Ranges ◽  
American Marten ◽  
Individual Level ◽  
The Individual

American marten (Martes americana (Turton, 1806)) are generally considered to be reliant upon and most successful in continuous late-successional coniferous forests. By contrast, young seral forests and deciduous-dominated forests are assumed to provide low-quality marten habitat, primarily as a result of insufficient structure, overhead cover, and prey. This study examined a moderate-density population of marten in northeastern British Columbia in what appeared to be comparatively low-quality, deciduous-dominated habitat, overgrown agricultural land primarily consisting of 30- to 40-year-old stands of regenerating trembling aspen (Populus tremuloides Michx.). Over 4 years, we monitored 52 radio-collared marten. The population appeared to be stable, as indicated by large numbers of adults, relatively constant densities, long-term residency of many individuals, low mortality rates, and older age structure. Relatively small home ranges (males, 3.3 km2; females, 2.0 km2) implied good habitat quality and prey availability. Shearing (removal of immature forest cover) of 17% of the study area resulted in home range shifts at the individual level but no detectable impact at the population level. Categorically, marten avoided nonforested cover types and preferred mature coniferous (>25% conifer) stands (7% of the study area) but otherwise appeared to use all forested stands relative to their availability, including extensive use of deciduous-dominated stands and deciduous stands <40 years of age. Thus, these young deciduous forests appeared to have sufficient structure, overhead cover, and prey to maintain moderate densities of resident marten on a long-term basis.

scholarly journals Addressing the Pension Decumulation Phase of Employee Retirement Planning

2020 ◽  
Author(s):  
Jorge Miguel Ventura Bravo
Keyword(s):  
Mortality Data ◽  
Term Care ◽  
Individual Level ◽  
Bequest Motives ◽  
Care Services ◽  
Life Annuity ◽  
Financial Options ◽  
Income Stream ◽  
The Individual

Longevity increases and population ageing create challenges for all societal institutions, particularly those providing retirement income, healthcare, and long-term care services. At the individual level, an obvious question is how to ensure all retirees have an adequate, secure, stable, and predictable lifelong income stream that will allow them to maintain a target standard of living for, however, long the individual lives. In this chapter, we review and discuss the main pension decumulation options by explicitly modelling consumers’ behaviour and objectives though an objective function based on utility theory accounting for consumption and bequest motives and different risk preferences. Using a Monte-Carlo simulation approach calibrated to US financial market and mortality data, our results suggest that purchasing a capped participating longevity-linked life annuity at retirement including embedded longevity and financial options that allow the annuity provider to periodically revise annuity payments if observed survivorship and portfolio outcomes deviate from expected (or guaranteed) values at contract initiation deliver superior welfare results when compared with classical annuitization and non-annuitization decumulation strategies.

scholarly journals SOCIAL ELITES IN LATE IMPERIAL EKATERINBURG: A PROGRAM FOR HISTORICAL AND DEMOGRAPHIC RESEARCH

2021 ◽  
Vol 72 (3) ◽  
pp. 169-179
Author(s):  
Dmitry S. Bakharev ◽  
◽  
Elena M. Glavatskaya ◽  
Keyword(s):  
Social History ◽  
Reference Group ◽  
Historical Context ◽  
Evolutionary Mechanisms ◽  
Electronic Resource ◽  
Individual Level ◽  
Late Imperial ◽  
Social Elite ◽  
The Social ◽  
The Individual

This article develops a theoretical basis for studying the socio-demographic evolution of elites in local/urban historical communities. The authors analyzed the methodological and terminological apparatus used in modern elite studies and formulated the concept of “social elite” based on synthesizing the civilizational aspects of elite theory and modernization theory. The social elite is understood as a minority that is a reference group for the rest of society in the sphere of sociodemographic practices. A fruitful study of such an object is realistic only by employing mass nominative sources that recorded demographic events in individual lives. The most important nominative source which contains demographic and, in addition, social information about the demographically representative communities of imperial Russia, are metricheskie knigi — parish vital events records. The potential of this type of source is most effectively realized by transcribing the information into databases for subsequent quantitative analysis. The research was carried out based on the URAPP — “Ural Population Project” — a comprehensive electronic resource containing information from the Orthodox parishes records in Ekaterinburg for 1880–1919, now extended to about 57000 entries. The initial adaptation of the proposed model to the historical context of late imperial Ekaterinburg enabled us to identify a community of townspeople — the parish of the Orthodox Epiphany Cathedral — that was more modernized than the rest of the city. Concentrating the research focus on socio-demographic processes among the parishioners of this community at the individual level, will in the future make it possible to represent more fully the evolutionary mechanisms of the social elite in the late Imperial Russian city. The proposed scheme can be used to study the problems of Russian social history in the late 19th — early 20th centuries, primarily to identify the agents driving the socio-demographic modernization.

scholarly journals An extreme sea level indicator for the contiguous United States coastline

2019 ◽  
Vol 6 (1) ◽  
Author(s):  
Md. Mamunur Rashid ◽  
Thomas Wahl ◽  
Don P. Chambers ◽  
Francisco M. Calafat ◽  
William V. Sweet
Keyword(s):  
United States ◽  
Sea Level ◽  
Decadal Variability ◽  
Level Indicator ◽  
Relative Contribution ◽  
Level Data ◽  
Water Level Data ◽  
The Individual

AbstractWe develop an aggregated extreme sea level (ESL) indicator for the contiguous United States coastline, which is comprised of separate indicators for mean sea level (MSL) and storm surge climatology (SSC). We use water level data from tide gauges to estimate interannual to multi-decadal variability of MSL and SSC and identify coastline stretches where the observed changes are coherent. Both the MSL and SSC indicators show significant fluctuations. Indicators of the individual components are combined with multi-year tidal contributions into aggregated ESL indicators. The relative contribution of the different components varies considerably in time and space. Our results highlight the important role of interannual to multi-decadal variability in different sea level components in exacerbating, or reducing, the impacts of long-term MSL rise over time scales relevant for coastal planning and management. Regularly updating the proposed indicator will allow tracking changes in ESL posing a threat to many coastal communities, including the identification of periods where the likelihood of flooding is particularly large or small.

scholarly journals Resource acquisition and allocation traits in symbiotic rhizobia with implications for life-history outside of legume hosts

2018 ◽  
Vol 5 (12) ◽  
pp. 181124 ◽  
Author(s):  
Katherine E. Muller ◽  
R. Ford Denison
Keyword(s):  
Root Nodules ◽  
Natural Populations ◽  
Heritable Variation ◽  
Free Living ◽  
Term Survival ◽  
Individual Level ◽  
Dividing Cells ◽  
Term Functions ◽  
Microbial Symbionts

Resources that microbial symbionts obtain from hosts may enhance fitness during free-living stages when resources are comparatively scarce. For rhizobia in legume root nodules, diverting resources from nitrogen fixation to polyhydroxybutyrate (PHB) has been discussed as a source of host–symbiont conflict. Yet, little is known about natural variation in PHB storage and its implications for rhizobial evolution. We therefore measured phenotypic variation in natural rhizobia populations and investigated how PHB might contribute to fitness in the free-living stage. We found that natural populations of rhizobia from Glycine max and Chamaecrista fasciculata had substantial, heritable variation in PHB acquisition during symbiosis. A model simulating temperature-dependent metabolic activity showed that the observed range of stored PHB per cell could support survival for a few days, for active cells, or over a century for sufficiently dormant cells. Experiments with field-isolated Bradyrhizobium in starvation culture suggest PHB is partitioned asymmetrically in dividing cells, consistent with individual-level bet-hedging previously demonstrated in E. meliloti . High-PHB isolates used more PHB over the first month, yet still retained more PHB for potential long-term survival in a dormant state. These results suggest that stored resources like PHB may support both short-term and long-term functions that contribute to fitness in the free-living stage.

scholarly journals In Search of Network Sustainability: A Multi-Level Perspective on the Paradox of Cooperation and Competition in Networks

2018 ◽  
Vol 10 (7) ◽  
pp. 2466 ◽  
Author(s):  
Agata Austen
Keyword(s):  
Mutual Influence ◽  
Public Institutions ◽  
Non Profit ◽  
Individual Level ◽  
Cooperation And Competition ◽  
Multi Level ◽  
The Individual ◽  
Local Partnerships ◽  
Research Show

Although all types of public collaborative networks are aimed towards taking joint actions, relations between partner organizations are not always so explicit. Referring to the dialectic approach, it may be concluded that a number of tensions are identifiable in networks, among them tension between cooperation and competition. Understanding the tensions that exist in inter-organizational networks is vital for a proper comprehension of networks, as continuous efforts to meet multiple, divergent demands should bring about long–term sustainability. To examine the phenomena of cooperation and competition in interorganizational networks, a quantitative study on local partnerships among Social Welfare Centers and other public institutions and non-profit institutions was conducted. Using a multi-level perspective, the research introduces orientation towards both cooperation and competition at different levels of analysis and examines the tensions between them. The results of this research show that there is a mutual influence of orientation towards competition/cooperation, both at the individual level and the network level, and that there is a mutual influence of the reconciliation of the contradictions between orientation towards cooperation and orientation towards competition both at the individual level and the network level.

scholarly journals Marital strain trajectories over a quarter century and spouses’ loneliness: Couple-level and individual pathways

2019 ◽  
Vol 37 (3) ◽  
pp. 821-842 ◽  
Author(s):  
Kandauda A. S. Wickrama ◽  
Tae Kyoung Lee ◽  
Catherine Walker O’Neal
Keyword(s):  
Extended Period ◽  
Married Couples ◽  
Later Life ◽  
Well Being ◽  
Quarter Century ◽  
Individual Level ◽  
The Individual ◽  
Marital Strain ◽  
Over 40 Years

Although research suggests that stressful marital experiences may lead to feelings of loneliness in later life, little is known about the influence of marital strain over an extended period of time on loneliness in later years. Thus, in the present study, drawing from family systems and cognitive theories along with common fate and actor–partner interdependence modeling approaches, we hypothesized a hybrid model comprised of two multilevel pathways explaining the persistent influence of marital strain on loneliness, including: (a) a couple-level pathway and (b) an individual pathway involving within-spouse and between-spouse effects. Specifically, we investigated the influences of individual- and couple-level trajectories of marital strain over a period of 25 years (from 1991 to 2015) on loneliness outcomes in later years with a sample of 257 couples in enduring, long-term (over 40 years) marriages. The results mostly supported both hypothesized pathways. Consistent with the pathway involving a couple-level process, couple-level trajectories of marital strain predicted couples’ later-life loneliness as reflected by both spouses’ reports of loneliness (shared perceptions). In addition, at the individual level, each spouses’ unexplained variances (unique perception) in marital strain trajectories predicted his/her own later-life loneliness outcomes (within-spouse effect or actor effect). Findings are discussed as they relate to intervention and prevention programs focusing on the well-being of married couples in later life.

Union pay premium in China: an individual-level analysis

2016 ◽  
Vol 37 (4) ◽  
pp. 606-627 ◽  
Author(s):  
Morley Gunderson ◽  
Byron Y Lee ◽  
Hui Wang
Keyword(s):  
Wage Gap ◽  
Quantile Regressions ◽  
Pay Gap ◽  
Content Type ◽  
Individual Level ◽  
Relative Contribution ◽  
Nationally Representative ◽  
Union Impact ◽  
The Individual ◽  
The Impact

Purpose – The purpose of this paper is to estimate the union-nonunion pay gap impact separately for wages and bonuses as well as total compensation to include both wages and bonuses in China. The way in which the impact varies as control variables are added is illustrated as is how the impact varies by the type of firm ownership. The overall pay gap is also decomposed into a component due to differences in their pay determining characteristics as well as a component due to differences in their returns to those characteristics. These separate components are also calculated throughout the pay distribution. Design/methodology/approach – Using the 2010 China Family Panel Studies Survey, a nationally representative survey in China, the methodology involves different estimation procedures as appropriate for the nature of the data and the dependent variables. First the authors estimate a single equation to determine the union-nonunion pay gap. Then the authors estimate the union impact on the various components of compensation (wages and bonuses). Next the authors decompose the relative contribution of each factor in explaining the wage gap. Finally, quantile regressions are used to examine the union impact across various levels of the pay distribution. Findings – The authors find a gross union-nonunion pay gap (wages + bonuses) of 42 percent, dropping to 12 percent after controlling for the effect of other pay determining factors. The union impact on wages is only 8 percent, but bonuses are about twice as high for union workers. The union impact is essentially zero for (state-owned firms) SOEs and for foreign-owned firms but it is large at 16 percent for private firms and even larger at 22 percent for government agencies. Of the overall pay gap of 42 percent, about three-quarters is attributable to differences in their endowments of pay determining characteristics and about one-quarter to differences in the returns for the same endowments of characteristics. Quantile regressions reveal that the pure or adjusted union wage premium exhibits a u-shaped pattern being highest in the bottom and to a lesser extent the top of the pay distribution. Originality/value – There are a dearth of studies examining the union-nonunion pay gap in China. Of the studies that examine this issue, all of them are at the enterprise level with no studies at the individual level. Taking a nationally representative dataset at the individual level, the authors are able to estimate the union-nonunion pay gap in China. The authors identify the portion of the gap that reflects differences in endowments of pay determining characteristics and the portion that reflects different returns to those characteristics, and the relative contribution of the different variables to those components; and how these components change over the pay distribution. The authors also offer explanations for many of these patterns.

Voting Outcomes in the 1984 Democratic Party Primaries and Caucuses

1987 ◽  
Vol 81 (1) ◽  
pp. 67-84 ◽  
Author(s):  
T. Wayne Parent ◽  
Calvin C. Jillson ◽  
Ronald E. Weber
Keyword(s):  
Democratic Party ◽  
Aggregate Level ◽  
Individual Level ◽  
Primary Election ◽  
Electoral Outcomes ◽  
The Individual ◽  
Scholarly Inquiry ◽  
Level Analysis ◽  
Level Of Analysis

Scholarly inquiry concerning influences on electoral outcomes in the presidential nomination process, though extensive, has been conducted almost exclusively with data collected at the individual level of analysis. The Michigan model of normal vote analysis suggests that long-term influences measured at the aggregate level, such as the sociodemographic, economic, and ideological characteristics of the states, are also important in determining electoral outcomes. We present an aggregate-level analysis of state characteristics that affected the Hart, Jackson, and Mondale vote proportions in the 1984 Democratic caucuses and primaries. Our primary election models explain between 65% and 83% of the variance in candidate vote shares, with sociodemographic and economic factors as the leading indicators. In the caucuses, we find that campaign spending and sociodemographic influences are dominant in models that explain between 38% and 81% of the variance. We conclude with a brief discussion of what our findings mean for future Democratic candidates.

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