253 research outputs found

    The evolutionary demise of a social interaction: experimentally induced loss of traits involved in the supply and demand of care

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    Phenotypic plasticity enables animals to adjust their behavior flexibly to their social environment—sometimes through the expression of adaptive traits that have not been exhibited for several generations. We investigated how long social adaptations can usefully persist when they are not routinely expressed, by using experimental evolution to document the loss of social traits associated with the supply and demand of parental care. We allowed populations of burying beetles Nicrophorus vespilloides to evolve in two different social environments for 48 generations in the lab. In “Full Care” populations, traits associated with the supply and demand of parental care were expressed at every generation, whereas in “No Care” populations we prevented expression of these traits experimentally. We then revived trait expression in the No Care populations at generations 24, 43, and 48 by allowing parents to supply post-hatching care and compared these social traits with those expressed by the Full Care populations. We found that offspring demands for care and male provision of care in the No Care populations were lost sooner than female provision of care. We suggest that this reflects differences in the strength of selection for the expression of alternative traits in offspring, males and females, which can enhance fitness when post-hatching care is disrupted

    Towards a Capabilities Taxonomy for Prognostics and Health Management

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    This communication proposes the development by the PHM Society of a classification or taxonomy for the skills needed for the prognostics and health management (PHM) field. This taxonomy is a set of descriptors for each skill for a chosen range of competency levels: entry, working and mastery. This communication defines a structure and process to ensure application to real needs by employers, practitioners and training developers. Preliminary results of the development of Analytics, Test and Experiment Design and Cost Benefit Studies sub-domains within the PHM field are reported based on workshops at the PHM 2012 and 2013 Annual Conferences. Steps for a way forward are proposed and mechanisms for interested parties to participate are suggested. The PHM Society’s Education and Professional Development Committee would lead these efforts

    Why Youth Leave 4-H After the First Year: A Multistate Study

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    Enrollment in US youth development programs is decreasing annually. Research has shown that youth in the 4-H youth development program experience a broad range of positive youth development outcomes, including greater community contributions, healthier choices, higher academic competence, critical life and leadership skills such as problem-solving, goal setting, communication, responsibility, and a sense of belonging and purpose. Finding ways to retain youth in the program for more than a year or two can profoundly impact society due to the skills developed and opportunities provided to youth in 4-H. The purpose of this study was to understand why youth might leave the 4-H program after one year of involvement. Using data from a multiyear, multistate study of first-year 4-H members, we examined why youth might leave the program and what first-year experiences correlate with youth dropout. Quantitative and qualitative survey data suggest that youth leave the program because of challenges related to belonging, welcoming, time, communication, interactions with adults, and overall organization. These findings can provide youth development faculty, programming staff, and volunteers with directions for improving the program to retain more youth

    Addressing Retention in Youth Programs: A Survey for Understanding Families\u27 Experiences

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    Research on retention in the 4-H youth development program has consistently shown that one of the primary indicators for youths\u27 dropping out of 4-H is being a first-year member. Extension 4-H professionals from California, Idaho, Wyoming, and New Jersey formed a team to study this issue. Our team surveyed first-year members and their parents/guardians to better understand why youths were not reenrolling in 4-H after their first year. This article introduces the survey used to assess the first-year experience and intent to reenroll. We discuss the survey development process, survey testing, lessons learned, and conclusions related to its future use

    The Use of Biomonitoring Data in Exposure and Human Health Risk Assessments

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    Biomonitoring uses analytic methods that permit the accurate measurement of low levels of environmental chemicals in human tissues. However, depending on the intended use, biomonitoring, like all exposure tools, may not be a stand-alone exposure assessment tool for some of its environmental public health uses. Although biomonitoring data demonstrate that many environmental chemicals are absorbed in human tissues, uncertainty exists regarding if and at what concentrations many of these chemicals cause adverse health outcomes. Moreover, without exposure pathway information, it is difficult to relate biomonitoring results to sources and routes of exposure and develop effective health risk management strategies. In September 2004, the Health and Environmental Sciences Institute, U.S. Environmental Protection Agency, Centers for Disease Control and Prevention, Agency for Toxic Substances and Disease Registry, and International Council of Chemical Associations co-sponsored the International Biomonitoring Workshop, which explored the processes and information needed for placing biomonitoring data into perspective for risk assessment purposes, with special emphasis on integrating biomarker measurements of exposure, internal dose, and potential health outcome. Scientists from international governments, academia, and industry recommended criteria for applying biomonitoring data for various uses. Six case studies, which are part of this mini-monograph, were examined: inorganic arsenic, methyl eugenol, organophosphorus pesticides, perfluorooctanesulfonate, phthalates, and polybrominated diphenyl ethers. Based on the workshop and follow-up discussions, this overview article summarizes lessons learned, identifies data gaps, outlines research needs, and offers guidance for designing and conducting biomonitoring studies, as well as interpreting biomonitoring data in the context of risk assessment and risk management

    International Coercion, Emulation and Policy Diffusion: Market-Oriented Infrastructure Reforms, 1977-1999

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    Why do some countries adopt market-oriented reforms such as deregulation, privatization and liberalization of competition in their infrastructure industries while others do not? Why did the pace of adoption accelerate in the 1990s? Building on neo-institutional theory in sociology, we argue that the domestic adoption of market-oriented reforms is strongly influenced by international pressures of coercion and emulation. We find robust support for these arguments with an event-history analysis of the determinants of reform in the telecommunications and electricity sectors of as many as 205 countries and territories between 1977 and 1999. Our results also suggest that the coercive effect of multilateral lending from the IMF, the World Bank or Regional Development Banks is increasing over time, a finding that is consistent with anecdotal evidence that multilateral organizations have broadened the scope of the “conditionality” terms specifying market-oriented reforms imposed on borrowing countries. We discuss the possibility that, by pressuring countries into policy reform, cross-national coercion and emulation may not produce ideal outcomes.http://deepblue.lib.umich.edu/bitstream/2027.42/40099/3/wp713.pd

    Analysis of candidate genes for macular telangiectasia type 2

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    Purpose: To find the gene(s) responsible for macular telangiectasia type 2 (MacTel) by a candidate-gene screening approach.Methods: Candidate genes were selected based on the following criteria: those known to cause or be associated with diseases with phenotypes similar to MacTel, genes with known function in the retinal vasculature or macular pigment transport, genes that emerged from expression microarray data from mouse models designed to mimic MacTel phenotype characteristics, and genes expressed in the retina that are also related to diabetes or hypertension, which have increased prevalence in MacTel patients. Probands from eight families with at least two affected individuals were screened by direct sequencing of 27 candidate genes. Identified nonsynonymous variants were analyzed to determine whether they cosegregate with the disease in families. Allele frequencies were determined by TaqMan analysis of the large MacTel and control cohorts.Results: We identified 23 nonsynonymous variants in 27 candidate genes in at least one proband. Of these, eight were known single nucleotide polymorphisms (SNPs) with allele frequencies of >0.05; these variants were excluded from further analyses. Three previously unidentified missense variants, three missense variants with reported disease association, and five rare variants were analyzed for segregation and/or allele frequencies. No variant fulfilled the criteria of being causal for MacTel. A missense mutation, p.Pro33Ser in frizzled homolog (Drosophila) 4 (FZD4), previously suggested as a disease-causing variant in familial exudative vitreoretinopathy, was determined to be a rare benign polymorphism.Conclusions: We have ruled out the exons and flanking intronic regions in 27 candidate genes as harboring causal mutations for MacTel

    Using individual-based bioenergetic models to predict the aggregate effects of disturbance on populations : a case study with beaked whales and Navy sonar

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    Funding: This research was supported by the Office of Naval Research (https://www.onr.navy.mil/) grant N0001419WX00431 and N000142012045: “Integrating information on displacement caused by mid-frequency active sonar and measurements of prey field into a population consequences of disturbance model for beaked whales” awarded to Dave Moretti, ND, SW, JH, LT, KB-B, AdR & VH. Funding support for tagging was provided by the US Navy's Office of Naval Research and Living Marine Resources program, the Chief of Naval Operations' Energy and Environmental Readiness Division and the NOAA Fisheries Ocean Acoustics Program.Anthropogenic activities can lead to changes in animal behavior. Predicting population consequences of these behavioral changes requires integrating short-term individual responses into models that forecast population dynamics across multiple generations. This is especially challenging for long-lived animals, because of the different time scales involved. Beaked whales are a group of deep-diving odontocete whales that respond behaviorally when exposed to military mid-frequency active sonar (MFAS), but the effect of these nonlethal responses on beaked whale populations is unknown. Population consequences of aggregate exposure to MFAS was assessed for two beaked whale populations that are regularly present on U.S. Navy training ranges where MFAS is frequently used. Our approach integrates a wide range of data sources, including telemetry data, information on spatial variation in habitat quality, passive acoustic data on the temporal pattern of sonar use and its relationship to beaked whale foraging activity, into an individual-based model with a dynamic bioenergetic module that governs individual life history. The predicted effect of disturbance from MFAS on population abundance ranged between population extinction to a slight increase in population abundance. These effects were driven by the interaction between the temporal pattern of MFAS use, baseline movement patterns, the spatial distribution of prey, the nature of beaked whale behavioral response to MFAS and the top-down impact of whale foraging on prey abundance. Based on these findings, we provide recommendations for monitoring of marine mammal populations and highlight key uncertainties to help guide future directions for assessing population impacts of nonlethal disturbance for these and other long-lived animals.Publisher PDFPeer reviewe
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