1,661 research outputs found

    The workings of the single member plurality electoral system in India and the need for reform

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    India uses single member plurality system (SMPS) to elect the members of the lower house of its national parliament and the state assemblies. Under SMPS, elections are conducted for separate geographical areas, known as constituencies or districts, and the electors cast one vote each for a candidate with the winner being the candidate who gets the plurality of votes. SMPS is traditionally defended primarily on the grounds of simplicity and its tendency to produce winning candidates, which promotes a link between constituents and their representatives. It tends to provide a clear-cut choice for voters between two main parties, and is expected to gives rise to single-party rather than coalition governments. It also has the benefit of excluding extremist parties from gaining representation, unless their support is geographically concentrated

    Haploinsufficiency and reduced expression of genes localized to the 8p chromosomal region in human prostate tumors

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    Cytogenetic and molecular studies have suggested that deletion or rearrangement of sequences that map to the short arm of chromosome 8 may be permissive for tumorigenesis in several organ systems, and in human prostate tumors in particular. In this study, we hypothesized that genes deleted for one copy and localized to the 8p chromosomal region may be transcriptionally down-regulated or ablated in affected human prostate tumor tissues. To test this hypothesis, we used cDNA microarray analysis to determine the transcriptional profiles for 259 transcribed sequences mapping to the 8p chromosomal region for seven human prostate tumor xenografts, completely characterized for numerical and structural alterations on chromosome 8, and five normal human prostate tissues. These experiments identified 33 genes differentially expressed between normal and malignant prostate tissues, the majority of which (28/33, 85%) were transcriptionally down-regulated in malignant compared to normal human prostate tissues. These findings, that haploinsufficiency and transcriptional down-regulation for genes mapping to 8p are largely coincident in human prostate tumors, should provide a powerful tool for the identification of tumor-suppressor genes associated with human prostate cancer initiation and progression. © 2003 Wiley-Liss, Inc.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/35134/1/10226_ftp.pd

    Reduced body weight is a common effect of gene knockout in mice

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    <p>Abstract</p> <p>Background</p> <p>During a search for obesity candidate genes in a small region of the mouse genome, we noticed that many genes when knocked out influence body weight. To determine whether this was a general feature of gene knockout or a chance occurrence, we surveyed the Jackson Laboratory Mouse Genome Database for knockout mouse strains and their phenotypes. Body weights were not available for all strains so we also obtained body weight information by contacting a random sample of investigators responsible for a knockout strain.</p> <p>Results</p> <p>We classified each knockout mouse strain as (1) lighter and smaller, (2) larger and heavier, or (3) the same weight, relative to control mice. We excluded knockout strains that died early in life, even though this type of lethality is often associated with a small embryo or reduced body size. Based on a dataset of 1,977 knockout strains, we found that that 31% of viable knockout mouse strains weighed less and an additional 3% weighed more than did controls.</p> <p>Conclusion</p> <p>Body weight is potentially a latent variable in about a third of experiments that use knockout mice and should be considered in interpreting experimental outcomes, e.g., in studies of hypertension, drug and hormone metabolism, organ development, cell proliferation and apoptosis, digestion, heart rate, or atherosclerosis. If we assume that the knockout genes we surveyed are representative then upward of 6,000 genes are predicted to influence the size of a mouse. Body weight is highly heritable, and numerous quantitative trait loci have been mapped in mice, but "multigenic" is an insufficient term for the thousands of loci that could contribute to this complex trait.</p

    The frequency of occurrence of novae hosting an ONe white dwarf

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    In this paper, we revisit the problem of the determination of the frequency of occurrence of galactic nova outbursts which involve an oxygen-neon (ONe) white dwarf. The improvement with respect to previous work on the subject derives from the fact that we use the results that our evolutionary calculations provide for the final mass and for the chemical profiles of intermediate-to-massive primary components of close binary systems. In particular, the final evolutionary stages, such as the carbon burning phase, have been carefully followed for the whole range of masses of interest. The chemical profiles obtained with our evolutionary code are of interest in determining the chemical composition of the ejecta after being processed through the thermonuclear runaway, although such other factors as the efficiency of the mixing between the accreted material and that of the underlying white dwarf must also be considered. In our calculations of the frequency of occurrence of nova outbursts involving an ONe white dwarf, we also take into account the observational selection effects introduced by the different recurrence times of the outbursts and by the spatial distribution of novae. In spite of the very different evolutionary sequences, we find that approximately 1/3 of the novae observed in outburst should involve an oxygen-neon white dwarf, in agreement with previous theoretical estimates.Comment: 9 pages, 6 figures, accepted for publication in A&

    Gravitational Waves From Known Pulsars: Results From The Initial Detector Era

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    We present the results of searches for gravitational waves from a large selection of pulsars using data from the most recent science runs (S6, VSR2 and VSR4) of the initial generation of interferometric gravitational wave detectors LIGO (Laser Interferometric Gravitational-wave Observatory) and Virgo. We do not see evidence for gravitational wave emission from any of the targeted sources but produce upper limits on the emission amplitude. We highlight the results from seven young pulsars with large spin-down luminosities. We reach within a factor of five of the canonical spin-down limit for all seven of these, whilst for the Crab and Vela pulsars we further surpass their spin-down limits. We present new or updated limits for 172 other pulsars (including both young and millisecond pulsars). Now that the detectors are undergoing major upgrades, and, for completeness, we bring together all of the most up-to-date results from all pulsars searched for during the operations of the first-generation LIGO, Virgo and GEO600 detectors. This gives a total of 195 pulsars including the most recent results described in this paper.United States National Science FoundationScience and Technology Facilities Council of the United KingdomMax-Planck-SocietyState of Niedersachsen/GermanyAustralian Research CouncilInternational Science Linkages program of the Commonwealth of AustraliaCouncil of Scientific and Industrial Research of IndiaIstituto Nazionale di Fisica Nucleare of ItalySpanish Ministerio de Economia y CompetitividadConselleria d'Economia Hisenda i Innovacio of the Govern de les Illes BalearsNetherlands Organisation for Scientific ResearchPolish Ministry of Science and Higher EducationFOCUS Programme of Foundation for Polish ScienceRoyal SocietyScottish Funding CouncilScottish Universities Physics AllianceNational Aeronautics and Space AdministrationOTKA of HungaryLyon Institute of Origins (LIO)National Research Foundation of KoreaIndustry CanadaProvince of Ontario through the Ministry of Economic Development and InnovationNational Science and Engineering Research Council CanadaCarnegie TrustLeverhulme TrustDavid and Lucile Packard FoundationResearch CorporationAlfred P. Sloan FoundationAstronom

    Global evidence of gender equity in academic health research: a scoping review

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    Objectives: To chart the global literature on gender equity in academic health research. Design: Scoping review. Participants: Quantitative studies were eligible if they examined gender equity within academic institutions including health researchers. Primary and secondary outcome measures: Outcomes related to equity across gender and other social identities in academia: (1) faculty workforce: representation of all genders in university/faculty departments, academic rank or position and salary; (2) service: teaching obligations and administrative/non-teaching activities; (3) recruitment and hiring data: number of applicants by gender, interviews and new hires for various rank; (4) promotion: opportunities for promotion and time to progress through academic ranks; (5) academic leadership: type of leadership positions, opportunities for leadership promotion or training, opportunities to supervise/mentor and support for leadership bids; (6) scholarly output or productivity: number/type of publications and presentations, position of authorship, number/value of grants or awards and intellectual property ownership; (7) contextual factors of universities; (8) infrastructure; (9) knowledge and technology translation activities; (10) availability of maternity/paternity/parental/family leave; (11) collaboration activities/opportunities for collaboration; (12) qualitative considerations: perceptions around promotion, finances and support. Results: Literature search yielded 94 798 citations; 4753 full-text articles were screened, and 562 studies were included. Most studies originated from North America (462/562, 82.2%). Few studies (27/562, 4.8%) reported race and fewer reported sex/gender (which were used interchangeably in most studies) other than male/female (11/562, 2.0%). Only one study provided data on religion. No other PROGRESS-PLUS variables were reported. A total of 2996 outcomes were reported, with most studies examining academic output (371/562, 66.0%). Conclusions: Reviewed literature suggest a lack in analytic approaches that consider genders beyond the binary categories of man and woman, additional social identities (race, religion, social capital and disability) and an intersectionality lens examining the interconnection of multiple social identities in understanding discrimination and disadvantage. All of these are necessary to tailor strategies that promote gender equity. Trial registration number: Open Science Framework: https://osf.io/8wk7e/

    Mathematical Modeling of Malaria Infection with Innate and Adaptive Immunity in Individuals and Agent-Based Communities

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    Background: Agent-based modeling of Plasmodium falciparum infection offers an attractive alternative to the conventional Ross-Macdonald methodology, as it allows simulation of heterogeneous communities subjected to realistic transmission (inoculation patterns). Methodology/Principal Findings: We developed a new, agent based model that accounts for the essential in-host processes: parasite replication and its regulation by innate and adaptive immunity. The model also incorporates a simplified version of antigenic variation by Plasmodium falciparum. We calibrated the model using data from malaria-therapy (MT) studies, and developed a novel calibration procedure that accounts for a deterministic and a pseudo-random component in the observed parasite density patterns. Using the parasite density patterns of 122 MT patients, we generated a large number of calibrated parameters. The resulting data set served as a basis for constructing and simulating heterogeneous agent-based (AB) communities of MT-like hosts. We conducted several numerical experiments subjecting AB communities to realistic inoculation patterns reported from previous field studies, and compared the model output to the observed malaria prevalence in the field. There was overall consistency, supporting the potential of this agent-based methodology to represent transmission in realistic communities. Conclusions/Significance: Our approach represents a novel, convenient and versatile method to model Plasmodiu

    A novel piggybac transposon inducible expression system identifies a role for akt signalling in primordial germ cell migration

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    In this work, we describe a single piggyBac transposon system containing both a tet-activator and a doxycycline-inducible expression cassette. We demonstrate that a gene product can be conditionally expressed from the integrated transposon and a second gene can be simultaneously targeted by a short hairpin RNA contained within the transposon, both in vivo and in mammalian and avian cell lines. We applied this system to stably modify chicken primordial germ cell (PGC) lines in vitro and induce a reporter gene at specific developmental stages after injection of the transposon-modified germ cells into chicken embryos. We used this vector to express a constitutively-active AKT molecule during PGC migration to the forming gonad. We found that PGC migration was retarded and cells could not colonise the forming gonad. Correct levels of AKT activation are thus essential for germ cell migration during early embryonic development
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