168 research outputs found
Explorations in Economic Research, Volume 4, number 3 (New Directions in Federal Economic Development Programs)
INTROGRESSION OF COYOTE MITOCHONDRIAL DNA INTO SYMPATRIC NORTH AMERICAN GRAY WOLF POPULATIONS
Mitochondrial DNA (mtDNA) genotypes of gray wolves and coyotes from localities throughout North America were determined using restriction fragment length polymorphisms. Of the 13 genotypes found among the wolves, 7 are clearly of coyote origin, indicating that genetic transfer of coyote mtDNA into wolf populations has occurred through hybridization. The transfer of mtDNA appears unidirectional from coyotes into wolves because no coyotes sampled have a wolf-derived mtDNA genotype. Wolves possessing coyote-derived genotypes are confined to a contiguous geographic region in Minnesota, Ontario, and Quebec, and the frequency of coyote- type mtDNA in these wolf populations is high (\u3e 500%). The ecological history of the hybrid zone suggests that hybridization is taking place in regions where coyotes have only recently become abundant following conversion of forests to farmlands. Dispersing male wolves unable to find conspecific mates may be pairing with female coyotes in deforested areas bordering wolf territories. Our results demonstrate that closely related species of mobile terrestrial vertebrates have the potential for extensive genetic exchange when ecological conditions change suddenly
A microfabricated deformability-based flow cytometer with application to malaria
Malaria resulting from Plasmodium falciparum infection is a major cause of human suffering and mortality. Red blood cell (RBC) deformability plays a major role in the pathogenesis of malaria. Here we introduce an automated microfabricated “deformability cytometer” that measures dynamic mechanical responses of 10[superscript 3] to 10[superscript 4] individual RBCs in a cell population. Fluorescence measurements of each RBC are simultaneously acquired, resulting in a population-based correlation between biochemical properties, such as cell surface markers, and dynamic mechanical deformability. This device is especially applicable to heterogeneous cell populations. We demonstrate its ability to mechanically characterize a small number of P. falciparum-infected (ring stage) RBCs in a large population of uninfected RBCs. Furthermore, we are able to infer quantitative mechanical properties of individual RBCs from the observed dynamic behavior through a dissipative particle dynamics (DPD) model. These methods collectively provide a systematic approach to characterize the biomechanical properties of cells in a high-throughput manner.National Institutes of Health (U.S.) (Grant R01 HL094270-01A1)National Institutes of Health (U.S.) (Grant 1-R01-GM076689-01)Singapore-MIT Alliance for Research and Technology Cente
A media framing analysis of urban flooding in Nigeria: current narratives and implications for policy
© 2017, The Author(s). A critical element of current flood management is the importance of engaging key policy actors when policy decisions are to be made. However, there is still only limited understanding of how narratives of flood management actors may influence flood management policies, even though there is a suggestion that actors can strategically use their narratives to influence policy directions. In a developing country like Nigeria, there are still questions around lessons that can be learnt from understanding the narratives of policy actors, to unravel the complex nature of strategies and policy directions in managing urban floods. To help fill these gaps, this paper uses quantitative content analysis to explore the frame of five policy actor groups (government, local communities, business, multilateral organisations and non-governmental organisations (NGOs)) as expressed in local and national newspapers between 2012 and 2016 to understand their narratives of causes and strategies to solve the problem of urban flooding in Nigeria. The narratives of government, local communities and businesses align with the premise that flooding can and should be prevented whilst that of multilateral and business actors champion adaptation strategies on the basis that flooding is inevitable and hence more energy should be directed at ‘living with water’—emergency response, damage reduction and the aftermath. The study also identified areas of potential consensus and conflict between direct actors such as government and local communities on the one hand and funders on the other. Better discussion among actors aiding understanding of contemporary thinking and local realities will aid policy-making and policy implementation in the Nigerian context. An important step will be in the collaborative design of an urgently needed ‘Nigerian policy on flooding’ which currently does not exist
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