196 research outputs found

    Sutures and contact homology I

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    We define a relative version of contact homology for contact manifolds with convex boundary, and prove basic properties of this relative contact homology. Similar considerations also hold for embedded contact homology

    Political Context, Issue Salience, and Selective Attentiveness: Constituent Knowledge of the Clarence Thomas Confirmation Vote

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    Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/72941/1/0022-3816.00090.pd

    Report on Provisional Ballots and American Elections

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    Both empirical and anecdotal data indicate that the use of provisional ballots in U.S. elections is a mixed bag. On the one hand, providing voters whose eligibility is unclear with an opportunity to cast a provisional ballot might prevent many voters from being disenfranchised. Indeed, the evidence from several states (for example, in California provisional ballots were estimated to be 5.8% of all ballots cast in 2008) indicates that the incidence of disputed eligibility can be quite substantial, and that provisional balloting options are substantively important. On the other hand, those states with provisional balloting systems may be less likely to seek to improve their registration, voter list, and election administration procedures, as provisional ballots provide a “fail-safe” option. We assume that the goal here is to (a) reduce incidences in which voter eligibility is at issue, and (b) provide an opportunity for all eligible voters to participate. In light of these goals, we recommend the best practices identified in the U.S. Election Assistance Commission’s 2010 report on provisional voting: improving voter outreach/communication, adding to staff and poll worker training, encouraging more consistent and comprehensive Election Day management procedures, and strengthening procedures for offering and counting provisional ballots as well as upgrading post-election statistical systems. These recommendations respect differences between and amongst the states, but provide a pathway for achieving consistency within states and improving voting procedures across the board. We also recommend that provisional ballot procedures are consistent within a given state, that younger voters be targeted for outreach, that provisional voting data be integrated into the voter lists and analyzed to inform outreach, and that both Election Day and (especially) post-election procedures for using and counting provisional ballots be strictly defined, understood, and implemented by election administrators

    Miniature standoff Raman probe for neurosurgical applications

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    Removal of intrinsic brain tumors is a delicate process, where a high degree of specificity is required to remove all of the tumor tissue without damaging healthy brain. The accuracy of this process can be greatly enhanced by intraoperative guidance. Optical biopsies using Raman spectroscopy are a minimally invasive and lower-cost alternative to current guidance methods. A miniature Raman probe for performing optical biopsies of human brain tissue is presented. The probe allows sampling inside a conventional stereotactic brain biopsy system: a needle of length 200 mm and inner diameter of 1.8 mm. By employing a miniature stand-off Raman design, the probe removes the need for any additional components to be inserted into the brain. Additionally, the probe achieves a very low internal silica background while maintaining good collection of Raman signal. To illustrate this, the probe is compared with a Raman probe that uses a pair of optical fibers for collection. The miniature stand-off Raman probe is shown to collect a comparable number of Raman scattered photons, but the Raman signal to background ratio is improved by a factor of five at Raman shifts below ∌500  cm−1. The probe’s suitability for use on tissue is demonstrated by discriminating between different types of healthy porcine brain tissue

    Consequences of sexual selection for fisheries-induced evolution: an exploratory analysis

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    Reproductive behaviour and mating system complexity may influence fisheries-induced evolution. Mate choice and intrasexual competition might favour late-, large-maturing genotypes in contrast to the selection imposed by many fisheries. Here, we simulate changes to the mean and variance in body size of Atlantic cod (Gadus morhua) concomitant with increased fishing intensity. Comparing selection differentials (S) for length under the assumptions that size does and does not affect reproductive success, we find that the strength of selection for smaller body size associated with increased fishing pressure depends on: (i) the initial variance in body size; (ii) changes to the variance in size with increasing fishing intensity; and (iii) the influence of size on reproductive success. If the initial variability in length is sufficiently high and its coefficient of variation (CV) increases with fishing intensity, the predicted evolutionary shift towards smaller size generated by fishing is less than that expected under the assumption that reproductive success is independent of size. However, if size influences reproduction and if the CV in body size declines as fishing pressure increases, a trend that may be characteristic of many intensively exploited populations, the strength of selection for smaller size is predicted to be comparatively rapid. We conclude that fisheries-induced evolution can be influenced by changes to the mean and variance of traits under sexual selection, and that the benefits of maintaining broad phenotypic variability in traits such as body size may be greater than previously thought

    African Swine Fever Virus Isolate, Georgia, 2007

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    The virus isolate introduced to the Caucasus in 2007 is closely related to a group of viruses, genotype II, circulating in Mozambique, Madagascar, and Zambia

    MOCVD of ultra-thin PV solar cell devices using a pyrite based p-i-n structure

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    Ultra-thin photovoltaic (PV) devices were produced by atmospheric pressure metal organic chemical vapour deposition (AP-MOCVD) incorporating a highly absorbing intermediate sulphurised FeSₓ layer into a CdS/CdTe structure. X ray diffraction (XRD) confirmed a transitional phase change to pyrite FeS₂ after post growth sulphur (S) annealing of the FeSₓ layer between 400⁰C and 500⁰C. Devices using a superstrate configuration incorporating a sulphurised or non sulphurised FeSₓ layer were compared to p-n devices with only a CdS/CdTe structure. Devices with sulphurised FeSₓ layers performed least efficiently, even though pyrite fractions were present. Rutherford back scattering (RBS) confirmed deterioration of the CdS/FeSₓ interface due to S inter-diffusion during the annealing process

    Soft-bottom fishes and spatial protection: findings from a temperate marine protected area

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    Numerous studies over the last decades have focused on marine protected areas (MPAs) and their effects on fish communities. However, there is a knowledge gap regarding how species that live associated with soft-substrates (e.g., sand, mud) respond to spatial protection. We analyzed abundance, biomass and total lengths of the soft-bottom fishes in a multiple-use MPA in the north-eastern Atlantic, the Luiz Saldanha Marine Park (Portugal), during and after the implementation of its management plan. Data were collected by experimental fishing in areas with three different levels of protection, during the implementation period and for three years after full implementation of the MPA. Univariate analysis detected significant biomass increases between the two periods. Fish assemblages were mainly structured by depth and substrate, followed by protection level. Community composition analyses revealed significant differences between protection levels and between the two periods. Species exhibited a broad variation in their response to protection, and we hypothesize that factors such as species habitat preferences, body size and late maturity might be underlying determinants. Overall, this study provides some evidence of protection effectiveness in soft-bottom fish communities, supported by the significant increase in biomass in the protected areas and the positive trends of some species.project LIFE-BIOMARES [LIFE06 NAT/P/000192]; project BUFFER (ERA-Net BiodivERsA); company SECIL-Companhia Geral de Cal e Cimento S.A.; FCT-Foundation for Science and Technology [CCMAR/Multi/04326/2013, SFRH/BD/80771/2011]; Foundation for Science and Technology [SFRH/BD/80771/2011]; 2012 Sesimbra Scientific Priz

    Mutational analysis of the Aspergillus ambient pH receptor PalH underscores its potential as a target for antifungal compounds.

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    The pal/RIM ambient pH signalling pathway is crucial for the ability of pathogenic fungi to infect hosts. The Aspergillus nidulans 7-TMD receptor PalH senses alkaline pH, subsequently facilitating ubiquitination of the arrestin PalF. Ubiquitinated PalF triggers downstream signalling events. The mechanism(s) by which PalH transduces the alkaline pH signal to PalF is poorly understood. We show that PalH is phosphorylated in a signal dependent manner, resembling mammalian GPCRs, although PalH phosphorylation, in contrast to mammalian GPCRs, is arrestin dependent. A genetic screen revealed that an ambient-exposed region comprising the extracellular loop connecting TM4-TM5 and ambient-proximal residues within TM5 is required for signalling. In contrast, substitution by alanines of four aromatic residues within TM6 and TM7 results in a weak 'constitutive' activation of the pathway. Our data support the hypothesis that PalH mechanistically resembles mammalian GPCRs that signal via arrestins, such that the relative positions of individual helices within the heptahelical bundle determines the Pro316-dependent transition between inactive and active PalH conformations, governed by an ambient-exposed region including critical Tyr259 that potentially represents an agonist binding site. These findings open the possibility of screening for agonist compounds stabilizing the inactive conformation of PalH, which might act as antifungal drugs against ascomycetes
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