120 research outputs found

    "Context effects in a negative externality experiment"

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    This study investigates the degree to which framing and context influence observed rates of free-riding behavior in a negative externality laboratory experiment. Building on the work of Andreoni (1995a) and Messer et al. (2007) we frame the decision not to contribute to a public fund as generating a negative externality on other group members. The experimental treatments involving 252 subjects vary communication, voting, and the status quo of the initial endowment. Results indicate that allowing groups the opportunity to communicate and vote significantly reduces rates of free-riding, and this effect is especially pronounced when initial endowments are placed in the private as opposed to the public fund.Negative externality; voluntary contribution mechanism; cheap talk; voting; status quo bias; experimental economics

    The impact of information on behavior under an ambient-based policy for regulating nonpoint source pollution

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    Stemming from Segerson [1988], literature on nonpoint source pollution shows that ambient-based regulatory policies can induce polluters in a common watershed to comply with an exogenously determined emissions standard. This study uses laboratory economic experiments in a spatially heterogeneous setting to test the effectiveness of an ambient tax/subsidy policy in a setting with realistic in-stream nutrient transport dynamics when varying levels of ambient information about the pollution is available to the agents and the regulator. We find that increasing the frequency of ambient monitoring improves the spatial allocation of emissions reductions. In particular with more frequent monitoring, the ambient-based policy induces firms further from the monitoring point to reduce emissions significantly more than downstream firms. Overall, the results suggest that enhanced information, especially enhanced temporal resolution, leads to efficiency gains

    Characterizing Heterogeneous Behavior of Non-Point-Source Polluters in a Spatial Game under Alternate Sensing and Incentive Designs

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    Behavioral research on natural resource management has revealed a number of variables that can impact collective action. This research builds upon an interactive decision game using experimental economics methods with a focus on production decisions and the corresponding impact they have on ambient water quality. Using hierarchical clustering algorithms, four primary types of behavior are identified: competitive, hypercompetitive, cooperative, and hypercooperative. The results from the experiment are used to test the following three hypotheses: (1) financial incentives increase cooperative behavior, (2) increasing the number and frequency of water quality sensors increases cooperative behavior, and (3) the spatial location of the agents and sensors affect cooperative behavior. Mixed-effect multinomial logistic models reveal that policy incentives, sensor location, and frequency of sensing alter the behavioral strategies of decision makers in the experiment and that outcomes vary by spatial location. From a watershed planning perspective, minimal investments in advanced environmental monitoring/sensing systems can potentially have large effects in improving water quality; however, there is also some evidence of marginal diminishing returns associated with such investments

    Improved gastrointestinal profile with diroximel fumarate is associated with a positive impact on quality of life compared with dimethyl fumarate: Results from the randomized, double-blind, phase III EVOLVE-MS-2 study

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    BACKGROUND: Diroximel fumarate (DRF) is a novel oral fumarate approved for relapsing forms of multiple sclerosis (MS). DRF demonstrated significantly improved gastrointestinal (GI) tolerability METHODS: A RESULTS: In total, 504 patients (DRF, CONCLUSIONS: The improved GI tolerability with DRF translated into clinically meaningful benefits to QoL, as patients experienced less impact on daily life and work and required less concomitant symptomatic medication use. TRIAL REGISTRATION: [ClinicalTrials.gov identifier: NCT03093324]

    Emergence potential of sylvatic dengue virus type 4 in the urban transmission cycle is restrained by vaccination and homotypic immunity

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    Sylvatic dengue viruses (DENV) are both evolutionarily and ecologically distinct from human DENV and are maintained in an enzootic transmission cycle. Evidence of sylvatic human infections from West Africa and Southeast Asia suggests that sylvatic DENV come into regular contact with humans. Thus, this potential of emergence into the human transmission cycle could limit the potential for eradicating this cycle with vaccines currently in late stages of development. We assessed the likelihood of sylvatic DENV-4 emergence in the face of natural immunity to current human strains and vaccination with two DENV-4 vaccine candidates. Our data indicate homotypic neutralization of sylvatic and human DENV-4 strains by human primary convalescent and vaccinee sera but limited heterotypic immunity. These results suggest that emergence of sylvatic strains into the human cycle would be limited by homotypic immunity mediated by virus neutralizing antibodies produced by natural infection or vaccination

    Emergence potential of sylvatic dengue virus type 4 in the urban transmission cycle is restrained by vaccination and homotypic immunity

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    Sylvatic dengue viruses (DENV) are both evolutionarily and ecologically distinct from human DENV and are maintained in an enzootic transmission cycle. Evidence of sylvatic human infections from West Africa and Southeast Asia suggests that sylvatic DENV come into regular contact with humans. Thus, this potential of emergence into the human transmission cycle could limit the potential for eradicating this cycle with vaccines currently in late stages of development. We assessed the likelihood of sylvatic DENV-4 emergence in the face of natural immunity to current human strains and vaccination with two DENV-4 vaccine candidates. Our data indicate homotypic neutralization of sylvatic and human DENV-4 strains by human primary convalescent and vaccinee sera but limited heterotypic immunity. These results suggest that emergence of sylvatic strains into the human cycle would be limited by homotypic immunity mediated by virus neutralizing antibodies produced by natural infection or vaccination

    Dengue viruses cluster antigenically but not as discrete serotypes.

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    The four genetically divergent dengue virus (DENV) types are traditionally classified as serotypes. Antigenic and genetic differences among the DENV types influence disease outcome, vaccine-induced protection, epidemic magnitude, and viral evolution. We characterized antigenic diversity in the DENV types by antigenic maps constructed from neutralizing antibody titers obtained from African green monkeys and after human vaccination and natural infections. Genetically, geographically, and temporally, diverse DENV isolates clustered loosely by type, but we found that many are as similar antigenically to a virus of a different type as to some viruses of the same type. Primary infection antisera did not neutralize all viruses of the same DENV type any better than other types did up to 2 years after infection and did not show improved neutralization to homologous type isolates. That the canonical DENV types are not antigenically homogeneous has implications for vaccination and research on the dynamics of immunity, disease, and the evolution of DENV.This research was supported in part by the Intramural Research Program of the US NIH, National Institute of Allergy and Infectious Diseases, European Union (EU) FP7 programs EMPERIE (223498) and ANTIGONE (278976), Human Frontier Science Program (HFSP) program grant P0050/2008, the NIH Director’s Pioneer Award DP1-OD000490-01, the FIRST program from the Bill and Melinda Gates Foundation and the Instituto Carlos Slim de la Salud (E.H.). The antigenic cartography toolkit was in part supported by NIAID-NIH Centers of Excellence for Influenza Research and Surveillance contracts HHSN266200700010C and HHSN272201400008C for use on influenza virus. L.C.K. was supported by the Gates Cambridge Scholarship and the NIH Oxford Cambridge Scholars Program. J.M.F. was supported by an MRC Fellowship (MR/K021885/1) and a Junior Research Fellowship from Homerton College Cambridge. E.C.H. was supported by an NHMRC Australia Fellowship. N.V. and R.B.T were supported by NIH contract HHSN272201000040I/HHSN27200004/D04.This is the author accepted manuscript. The final version is available from AAAS via http://dx.doi.org/10.1126/science.aac501

    Gene duplication and phenotypic changes in the evolution of Mammalian metabolic networks

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    Metabolic networks attempt to describe the complete suite of biochemical reactions available to an organism. One notable feature of these networks in mammals is the large number of distinct proteins that catalyze the same reaction. While the existence of these isoenzymes has long been known, their evolutionary significance is still unclear. Using a phylogenetically-aware comparative genomics approach, we infer enzyme orthology networks for sixteen mammals as well as for their common ancestors. We find that the pattern of isoenzymes copy-number alterations (CNAs) in these networks is suggestive of natural selection acting on the retention of certain gene duplications. When further analyzing these data with a machine-learning approach, we found that that the pattern of CNAs is also predictive of several important phenotypic traits, including milk composition and geographic range. Integrating tools from network analyses, phylogenetics and comparative genomics both allows the prediction of phenotypes from genetic data and represents a means of unifying distinct biological disciplines

    Baby Business: a randomised controlled trial of a universal parenting program that aims to prevent early infant sleep and cry problems and associated parental depression

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    <p>Abstract</p> <p>Background</p> <p>Infant crying and sleep problems (e.g. frequent night waking, difficulties settling to sleep) each affect up to 30% of infants and often co-exist. They are costly to manage and associated with adverse outcomes including postnatal depression symptoms, early weaning from breast milk, and later child behaviour problems. Preventing such problems could improve these adverse outcomes and reduce costs to families and the health care system. Anticipatory guidance-i.e. providing parents with information about normal infant sleep and cry patterns, ways to encourage self-settling in infants, and ways to develop feeding and settling routines <it>before </it>the onset of problems-could prevent such problems. This paper outlines the protocol for our study which aims to test an anticipatory guidance approach.</p> <p>Methods/Design</p> <p>750 families from four Local Government Areas in Melbourne, Australia have been randomised to receive the <it>Baby Business </it>program (intervention group) or usual care (control group) offered by health services. The <it>Baby Business </it>program provides parents with information about infant sleep and crying via a DVD and booklet (mailed soon after birth), telephone consultation (at infant age 6-8 weeks) and parent group session (at infant age 12 weeks). All English speaking parents of healthy newborn infants born at > 32 weeks gestation and referred by their maternal and child health nurse at their first post partum home visit (day 7-10 postpartum), are eligible. The primary outcome is parent report of infant night time sleep as a problem at four months of age and secondary outcomes include parent report of infant daytime sleep or crying as a problem, mean duration of infant sleep and crying/24 hours, parental depression symptoms, parent sleep quality and quantity and health service use. Data will be collected at two weeks (baseline), four months and six months of age. An economic evaluation using a cost-consequences approach will, from a societal perspective, compare costs and health outcomes between the intervention and control groups.</p> <p>Discussion</p> <p>To our knowledge this is the first randomised controlled trial of a program which aims to prevent both infant sleeping and crying problems and associated postnatal depression symptoms. If effective, it could offer an important public health prevention approach to these common, distressing problems.</p> <p>Trial registration number</p> <p>ISRCTN: <a href="http://www.controlled-trials.com/ISRCTN63834603">ISRCTN63834603</a></p
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