10,777 research outputs found

    Protocol for electrophysiological monitoring of carotid endarterectomies.

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    Near zero stroke rates can be achieved in carotid endarterectomy (CEA) surgery with selective shunting and electrophysiological neuromonitoring. though false negative rates as high as 40% have been reported. We sought to determine if improved training for interpretation of the monitoring signals can advance the efficacy of selective shunting with electrophysiological monitoring across multiple centers, and determine if other factors could contribute to the differences in reports. Processed and raw beta band (12.5-30 Hz) electroencephalogram (EEG) and median and tibial nerve somatosensory evoked potentials (SSEP) were monitored in 668 CEA cases at six surgical centers. A decrease in amplitude of 50% or more in any EEG or SSEP channel was the criteria for shunting or initiating a neuroprotective protocol. A reduction of 50% or greater in the beta band of the EEG or amplitude of the SSEP was observed in 150 cases. No patient showed signs of a cerebral infarct after surgery. Selective shunting based on EEG and SSEP monitoring can reduce CEA intraoperative stroke rate to a near zero level if trained personnel adopted standardized protocols. We also found that the rapid administration of a protective stroke protocol by attending anesthesiologists was an important aspect of this success rate

    A Configurable Matchmaking Framework for Electronic Marketplaces

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    E-marketplaces constitute a major enabler of B2B and B2C e-commerce activities. This paper proposes a framework for one of the central activities of e-marketplaces: matchmaking of trading intentions lodged by market participants. The framework identifies a core set of concepts and functions that are common to all types of marketplaces and can serve as the basis for describing the distinct styles of matchmaking employed within various market mechanisms. A prototype implementation of the framework based on Web services technology is presented, illustrating its ability to be dynamically configured to meet specific market needs and its potential to serve as a foundation for more fully fledged e-marketplace frameworks

    Lepton Asymmetry of the Universe and Charged Quark-Gluon Plasma

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    The lepton asymmetry of order one is not excluded experimentally and, if present, can lead to interesting phenomena in the early Universe. It is shown that, when the temperature is above the quark-hadron transition, the lepton asymmetry induces chemical potentials for electric charge and for baryon number, and makes the quark-gluon plasma electrically charged.Comment: 7 pages, 2 figures; v2: misprints in eqs. 10 and 13 correcte

    Environmental research on the new Lincoln University dairy farm

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    A major challenge to the New Zealand’s growing dairy industry is to achieve an annual productivity gain of 4% in order to remain internationally competitive. However, it is important to ensure that this productivity gain is achieved without significantly comprising the quality and integrity of New Zealand’s “clean and green” environment. There is increasing public concern about the effects of dairying on the environment, both within New Zealand and by our overseas customers. One of the main concerns is the possible threat to the quality of groundwater and surface water, particularly by nitrate, phosphate and microbial contaminants. Nitrate leaching from soil is of concern because of its impact on drinking water quality and the effects that nitrate can have on rivers and lakes. A high nitrate concentration in drinking water is a recognised health hazard and a high concentration in rivers and lakes can cause excessive growth of algae and weeds, which may reduce the fish population. Nitrate leaching also represents a financial cost to the farmer and a loss in soil fertility. The establishment of the new Lincoln University dairy farm is designed to enable us to develop and test practical methods to improve productivity and at the same time protect the environment. The objective of the environmental project on the new Lincoln University dairy farm is to develop best management practices under irrigation which will ensure that the dairy industry’s 4% productivity gain is achieved in a sustainable way, and that the wider environment is protected

    Hiding relativistic degrees of freedom in the early universe

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    We quantify the extent to which extra relativistic energy density can be concealed by a neutrino asymmetry without conflicting with the baryon asymmetry measured by the Wilkinson Microwave Anisotropy Probe (WMAP). In the presence of a large electron neutrino asymmetry, slightly more than seven effective neutrinos are allowed by Big Bang Nucleosynthesis (BBN) and WMAP at 2\sigma. The same electron neutrino degeneracy that reconciles the BBN prediction for the primordial helium abundance with the observationally inferred value also reconciles the LSND neutrino with BBN by suppressing its thermalization prior to BBN.Comment: 5 pages, 5 figure

    HST Grism Observations of a Gravitationally Lensed Redshift 10 Galaxy

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    We present deep spectroscopic observations of a Lyman-break galaxy candidate (hereafter MACS1149-JD) at z9.5z\sim9.5 with the Hubble\textit{Hubble} Space Telescope (HST\textit{HST}) WFC3/IR grisms. The grism observations were taken at 4 distinct position angles, totaling 34 orbits with the G141 grism, although only 19 of the orbits are relatively uncontaminated along the trace of MACS1149-JD. We fit a 3-parameter (zz, F160W mag, and Lyα\alpha equivalent width) Lyman-break galaxy template to the three least contaminated grism position angles using an MCMC approach. The grism data alone are best fit with a redshift of zgrism=9.530.60+0.39z_{\mathrm{grism}}=9.53^{+0.39}_{-0.60} (68%68\% confidence), in good agreement with our photometric estimate of zphot=9.510.12+0.06z_{\mathrm{phot}}=9.51^{+0.06}_{-0.12} (68%68\% confidence). Our analysis rules out Lyman-alpha emission from MACS1149-JD above a 3σ3\sigma equivalent width of 21 \AA{}, consistent with a highly neutral IGM. We explore a scenario where the red Spitzer\textit{Spitzer}/IRAC [3.6][4.5][3.6] - [4.5] color of the galaxy previously pointed out in the literature is due to strong rest-frame optical emission lines from a very young stellar population rather than a 4000 \AA{} break. We find that while this can provide an explanation for the observed IRAC color, it requires a lower redshift (z9.1z\lesssim9.1), which is less preferred by the HST\textit{HST} imaging data. The grism data are consistent with both scenarios, indicating that the red IRAC color can still be explained by a 4000 \AA{} break, characteristic of a relatively evolved stellar population. In this interpretation, the photometry indicate that a 34035+29340^{+29}_{-35} Myr stellar population is already present in this galaxy only 500 Myr\sim500~\mathrm{Myr} after the Big Bang.Comment: Accepted to ApJ. This is the accepted versio

    Technical Performance Reduces during the Extra-Time Period of Professional Soccer Match-Play

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    Despite the importance of extra-time in determining progression in specific soccer tournament matches, few studies have profiled the demands of 120-minutes of soccer match-play. With a specific focus on the extra-time period, and using a within-match approach, we examined the influence of prolonged durations of professional soccer match-play on markers of technical (i.e., skilled) performance. In 18 matches involving professional European teams played between 2010 and 2014, this retrospective study quantified the technical actions observed during eight 15-minute epochs (E1: 00:00–14:59 min, E2: 15:00-29:59 min, E3: 30:00-44:59 min, E4: 45:00-59:59 min, E5: 60:00-74:59 min, E6: 75:00-89:59 min, E7: 90:00-104:59 min, E8: 105:00-119:59 min). Analysis of players who completed the demands of the full 120 min of match-play revealed that the cumulative number of successful passes observed during E8 (61±23) was lower than E1-4 (E1: 88±23, P=0.001; E2: 77±21, P=0.005; E3: 79±18, P=0.001; E4: 80±21, P=0.001) and E7 (73±20, P=0.002). Similarly, the total number of passes made in E8 (71±25) was reduced when compared to E1 (102±22, P=0.001), E3 (91±19, P=0.002), E4 (93±22, P≤0.0005) and E7 (84±20, P=0.001). The cumulative number of successful dribbles reduced in E8 (9±4) when compared to E1 (14±4, P=0.001) and E3 (12±4, P≤0.0005) and the total time the ball was in play was less in E8 (504±61 s) compared to E1 (598±70 s, P≤0.0005). These results demonstrate that match-specific factors reduced particular indices of technical performance in the second half of extra-time. Interventions that seek to maintain skilled performance throughout extra-time warrant further investigation

    Big Bang Nucleosynthesis with Gaussian Inhomogeneous Neutrino Degeneracy

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    We consider the effect of inhomogeneous neutrino degeneracy on Big Bang nucleosynthesis for the case where the distribution of neutrino chemical potentials is given by a Gaussian. The chemical potential fluctuations are taken to be isocurvature, so that only inhomogeneities in the electron chemical potential are relevant. Then the final element abundances are a function only of the baryon-photon ratio η\eta, the effective number of additional neutrinos ΔNν\Delta N_\nu, the mean electron neutrino degeneracy parameter ξˉ\bar \xi, and the rms fluctuation of the degeneracy parameter, σξ\sigma_\xi. We find that for fixed η\eta, ΔNν\Delta N_\nu, and ξˉ\bar \xi, the abundances of helium-4, deuterium, and lithium-7 are, in general, increasing functions of σξ\sigma_\xi. Hence, the effect of adding a Gaussian distribution for the electron neutrino degeneracy parameter is to decrease the allowed range for η\eta. We show that this result can be generalized to a wide variety of distributions for ξ\xi.Comment: 9 pages, 3 figures, added discussion of neutrino oscillations, altered presentation of figure
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