128 research outputs found

    Minority Representation under Cumulative and Limited Voting

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    We examine minority representation resulting from modified at-large elections (cumulative and limited voting) used in U.S. localities in the 1990s. Hypotheses about the relative proportionality of descriptive representation under various local election systems are presented and tested. We find that CV/LV elections produced descriptive representation of African-Americans at levels similar to those in larger single-member district places, and at levels that exceed those from some small, southern SMD places. Results for Latino representation are more qualified. Our results offer encouragement for those interested in facilitating minority representation without using the acrimonious process of drawing districts on the basis of races

    Protected areas and poverty

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    Protected areas are controversial because they are so important for conservation and because they distribute fortune and misfortune unevenly. The nature of that distribution, as well as the terrain of protected areas themselves, have been vigorously contested. In particular, the relationship between protected areas and poverty is a long-running debate in academic and policy circles. We review the origins of this debate and chart its key moments. We then outline the continuing flashpoints and ways in which further evaluation studies could improve the evidence base for policy-making and conservation practice

    Angiosperm phylogeny: 17 genes, 640 taxa

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    Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/142064/1/ajb20704-sup-0010.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/142064/2/ajb20704.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/142064/3/ajb20704-sup-0001.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/142064/4/ajb20704-sup-0016.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/142064/5/ajb20704-sup-0017.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/142064/6/ajb20704-sup-0021.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/142064/7/ajb20704-sup-0003.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/142064/8/ajb20704-sup-0002.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/142064/9/ajb20704-sup-0011.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/142064/10/ajb20704-sup-0019.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/142064/11/ajb20704-sup-0015.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/142064/12/ajb20704-sup-0006.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/142064/13/ajb20704-sup-0020.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/142064/14/ajb20704-sup-0013.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/142064/15/ajb20704-sup-0004.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/142064/16/ajb20704-sup-0012.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/142064/17/ajb20704-sup-0005.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/142064/18/ajb20704-sup-0018.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/142064/19/ajb20704-sup-0009.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/142064/20/ajb20704-sup-0014.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/142064/21/ajb20704-sup-0007.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/142064/22/ajb20704-sup-0008.pd

    Angiosperm Phylogeny: 17 Genes, 640 Taxa

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    • Premise of the study : Recent analyses employing up to fi ve genes have provided numerous insights into angiosperm phylogeny, but many relationships have remained unresolved or poorly supported. In the hope of improving our understanding of angiosperm phylogeny, we expanded sampling of taxa and genes beyond previous analyses. • Methods : We conducted two primary analyses based on 640 species representing 330 families. The fi rst included 25 260 aligned base pairs (bp) from 17 genes (representing all three plant genomes, i.e., nucleus, plastid, and mitochondrion). The second included 19 846 aligned bp from 13 genes (representing only the nucleus and plastid). • Key results : Many important questions of deep-level relationships in the nonmonocot angiosperms have now been resolved with strong support. Amborellaceae, Nymphaeales, and Austrobaileyales are successive sisters to the remaining angiosperms ( Mesangiospermae ), which are resolved into Chloranthales + Magnoliidae as sister to Monocotyledoneae + [Ceratophyllaceae + Eudicotyledoneae ]. Eudicotyledoneae contains a basal grade subtending Gunneridae . Within Gunneridae , Gunnerales are sister to the remainder ( Pentapetalae ), which comprises (1) Superrosidae , consisting of Rosidae (including Vitaceae) and Saxifragales; and (2) Superasteridae , comprising Berberidopsidales, Santalales, Caryophyllales , Asteridae , and, based on this study, Dilleniaceae (although other recent analyses disagree with this placement). Within the major subclades of Pentapetalae , most deep-level relationships are resolved with strong support. • Conclusions : Our analyses confi rm that with large amounts of sequence data, most deep-level relationships within the angiosperms can be resolved. We anticipate that this well-resolved angiosperm tree will be of broad utility for many areas of biology, including physiology, ecology, paleobiology, and genomics

    COL4A1 Mutations Cause Ocular Dysgenesis, Neuronal Localization Defects, and Myopathy in Mice and Walker-Warburg Syndrome in Humans

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    Muscle-eye-brain disease (MEB) and Walker Warburg Syndrome (WWS) belong to a spectrum of autosomal recessive diseases characterized by ocular dysgenesis, neuronal migration defects, and congenital muscular dystrophy. Until now, the pathophysiology of MEB/WWS has been attributed to alteration in dystroglycan post-translational modification. Here, we provide evidence that mutations in a gene coding for a major basement membrane protein, collagen IV alpha 1 (COL4A1), are a novel cause of MEB/WWS. Using a combination of histological, molecular, and biochemical approaches, we show that heterozygous Col4a1 mutant mice have ocular dysgenesis, neuronal localization defects, and myopathy characteristic of MEB/WWS. Importantly, we identified putative heterozygous mutations in COL4A1 in two MEB/WWS patients. Both mutations occur within conserved amino acids of the triple-helix-forming domain of the protein, and at least one mutation interferes with secretion of the mutant proteins, resulting instead in intracellular accumulation. Expression and posttranslational modification of dystroglycan is unaltered in Col4a1 mutant mice indicating that COL4A1 mutations represent a distinct pathogenic mechanism underlying MEB/WWS. These findings implicate a novel gene and a novel mechanism in the etiology of MEB/WWS and expand the clinical spectrum of COL4A1-associated disorders

    The genetic architecture of the human cerebral cortex

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    The cerebral cortex underlies our complex cognitive capabilities, yet little is known about the specific genetic loci that influence human cortical structure. To identify genetic variants that affect cortical structure, we conducted a genome-wide association meta-analysis of brain magnetic resonance imaging data from 51,665 individuals. We analyzed the surface area and average thickness of the whole cortex and 34 regions with known functional specializations. We identified 199 significant loci and found significant enrichment for loci influencing total surface area within regulatory elements that are active during prenatal cortical development, supporting the radial unit hypothesis. Loci that affect regional surface area cluster near genes in Wnt signaling pathways, which influence progenitor expansion and areal identity. Variation in cortical structure is genetically correlated with cognitive function, Parkinson's disease, insomnia, depression, neuroticism, and attention deficit hyperactivity disorder
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