885 research outputs found

    Trade, gravity and aggregation

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    Gravity regressions are a common tool in the empirical international trade literature and serve an important function for many policy purposes. We study to what extent micro-level parameters can be recovered from gravity regressions estimated with aggregate data. We show that estimation of gravity equations in their original multiplicative form via Poisson pseudo maximum likelihood (PPML) is more robust to aggregation than estimation of log-linearized gravity equations via ordinary least squares (OLS). In the leading case where regressors do not vary at the micro level, PPML estimates obtained with aggregate data have a clear interpretation as trade-weighted averages of micro-level parameters that is not shared by OLS estimates. However, when regressors vary at the micro level, using disaggregated data is essential because in this case not even PPML can recover parameters of interest. We illustrate our results with an application to Baier and Bergstrand's (2007) influential study of the effects of trade agreements on trade flows. We examine how their findings change when estimation is performed at different levels of aggregation, and explore the consequences of aggregation for predicting the effects of trade agreements

    Multimodal Outcome Prognostication After Cardiac Arrest and Targeted Temperature Management: Analysis at 36 °C.

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    Targeted temperature management (TTM) represents the standard of care in comatose survivors after cardiac arrest (CA) and may be applied targeting 33° or 36 °C. While multimodal prognostication has been extensively tested for 33 °C, scarce information exists for 36 °C. In this cohort study, consecutive comatose adults after CA treated with TTM at 36 °C between July 2014 and October 2016 were included. A combination of neurological examination, electrophysiological features, and serum neuron-specific enolase (NSE) was evaluated for outcome prediction at 3 months (mortality; good outcome defined as cerebral performance categories (CPC) score of 1-2, poor outcome defined as CPC 3-5). We analyzed 61 patients. The presence of two or more predictors out of, unreactive electroencephalogram (EEG) background, epileptiform EEG, absent pupillary and/or corneal reflex, early myoclonus, bilaterally absent cortical somatosensory evoked potentials, and serum NSE >75 μg/l, had a high specificity for predicting mortality (positive predictive value [PPV] = 1.00, 95% CI 0.87-1.00) and poor outcome (PPV = 1.00, 95% CI 0.80-1.00). Reactive EEG background was highly sensitive for predicting good outcome (0.95, 95% CI 0.74-0.99). Prediction of outcome after CA and TTM targeting 36 °C seems valid in adults using the same features tested at 33 °C. A reactive EEG under TTM appears highly sensitive for good outcome

    Status epilepticus: impact of therapeutic coma on outcome.

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    OBJECTIVES: Therapeutic coma is advocated in guidelines for management of refractory status epilepticus; this is, however, based on weak evidence. We here address the specific impact of therapeutic coma on status epilepticus outcome. DESIGN: Retrospective assessment of a prospectively collected cohort. SETTING: Academic hospital. PATIENTS: Consecutive adults with incident status epilepticus lasting greater than or equal to 30 minutes, admitted between 2006 and 2013. MEASUREMENTS AND MAIN RESULTS: We recorded prospectively demographics, clinical status epilepticus features, treatment, and outcome at discharge and retrospectively medical comorbidities, hospital stay, and infectious complications. Associations between potential predictors and clinical outcome were analyzed using multinomial logistic regressions. Of 467 patients with incident status epilepticus, 238 returned to baseline (51.1%), 162 had new disability (34.6%), and 67 died (14.3%); 50 subjects (10.7%) were managed with therapeutic coma. Therapeutic coma was associated with poorer outcome in the whole cohort (relative risk ratio for new disability, 6.86; 95% CI, 2.84-16.56; for mortality, 9.10; 95% CI, 3.17-26.16); the effect was more important in patients with complex partial compared with generalized convulsive or nonconvulsive status epilepticus in coma. Prevalence of infections was higher (odds ratio, 3.81; 95% CI, 1.66-8.75), and median hospital stay in patients discharged alive was longer (16 d [range, 2-240 d] vs 9 d [range, 1-57 d]; p < 0.001) in subjects managed with therapeutic coma. CONCLUSIONS: This study provides class III evidence that therapeutic coma is associated with poorer outcome after status epilepticus; furthermore, it portends higher infection rates and longer hospitalizations. These data suggest caution in the straightforward use of this approach, especially in patients with complex partial status epilepticus

    Intravenous lacosamide in status epilepticus: Correlation between loading dose, serum levels, and clinical response.

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    Intravenous lacosamide (LCM) is increasingly used in the treatment of status epilepticus (SE), but optimal loading dose and target serum levels are unclear. We analysed the correlation between LCM serum levels after intravenous loading dose and clinical response. Retrospective study in two centres from December 2014 to May 2016 including consecutive SE patients treated with LCM, in which trough serum levels after intravenous loading dose were available. Trough levels were correlated with the loading dose and the clinical response, defined as LCM introduction terminating SE without the need of further treatment. Correlations were adjusted for other SE characteristics. Among 40 patients, 16 (40%) responded to LCM. LCM serum concentrations within the reference interval (10-20mg/l) were associated with loading doses of >9mg/kg (p=0.003; χ2). However, we observed no difference between LCM serum levels in responders (median 10.4mg/l) versus non-responders (median 9.5mg/l; p=0.36; U test), even after adjusting for other predictors of clinical outcome (SE severity, aetiology, and number of previous treatment). High intravenous LCM loading doses (>9mg/kg) were associated with serum levels within the reference interval, there was however no correlation with the clinical response. Prospective studies are needed to evaluate the benefit of increasing the LCM loading dose in SE

    Owyhee Russet: AVariety with High Yields of U.S. No. 1 Tubers, Excellent Processing Quality, and Moderate Resistance to Fusarium Dry Rot (\u3ci\u3eFusarium solani var. coeruleum\u3c/i\u3e)

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    Owyhee Russet (AO96160-3) originated from a cross between A89384-10 and A89512-3 in 1996. Owyhee Russet was released in 2009 by Oregon State University, in cooperation with the USDA-ARS and the Agricultural Experiment Stations of Idaho and Washington and is a product of the Northwest Potato Variety (Tri-State) Development Program. Owyhee Russet has semi-erect medium sized vines with medium to late maturity. The tubers are long, with a tan skin, medium russeting, and attractive tuber appearance for fresh market. Owyhee Russet was evaluated in several locations across the Northwest for more than 15 years. Total yield of Owyhee Russet is similar to that of Russet Burbank and Ranger Russet but significantly higher than Russet Norkotah. U.S. No.1 tuber yield of Owyhee Russet is significantly higher than Russet Burbank and Russet Norkotah, resulting in substantially higher marketable yield. Owyhee Russet tubers have significantly higher specific gravity than Russet Burbank and Russet Norkotah. Fry color following tuber storage at 4°C and 9°C is significantly lighter for Owyhee Russet than the comparison varieties. Relative strengths include high yield with a very high proportion of U.S. No.1 tubers, good tuber appearance and excellent processing quality, resistance to cold sweetening, common scab and Fusarium dry rot. Weaknesses include susceptibility to foliar and tuber late blight and susceptibility to metribuzin herbicide injury. Allelic patterns of five SSR markers have shown that Owyhee Russet has a distinctive DNA genetic fingerprint from its russet type reference varieties which are Ranger Russet, Russet Burbank, and Russet Norkotah

    Interplay among transversity induced asymmetries in hadron leptoproduction

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    In the fragmentation of a transversely polarized quark several left-right asymmetries are possible for the hadrons in the jet. When only one unpolarized hadron is selected, it exhibits an azimuthal modulation known as Collins effect. When a pair of oppositely charged hadrons is observed, three asymmetries can be considered, a di-hadron asymmetry and two single hadron asymmetries. In lepton deep inelastic scattering on transversely polarized nucleons all these asymmetries are coupled with the transversity distribution. From the high statistics COMPASS data on oppositely charged hadron-pair production we have investigated for the first time the dependence of these three asymmetries on the difference of the azimuthal angles of the two hadrons. The similarity of transversity induced single and di-hadron asymmetries is discussed. A new analysis of the data allows to establish quantitative relationships among them, providing for the first time strong experimental indication that the underlying fragmentation mechanisms are all driven by a common physical process.Comment: 6 figure

    Interplay among transversity induced asymmetries in hadron leptoproduction

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    In the fragmentation of a transversely polarized quark several left-right asymmetries are possible for the hadrons in the jet. When only one unpolarized hadron is selected, it exhibits an azimuthal modulation known as Collins effect. When a pair of oppositely charged hadrons is observed, three asymmetries can be considered, a di-hadron asymmetry and two single hadron asymmetries. In lepton deep inelastic scattering on transversely polarized nucleons all these asymmetries are coupled with the transversity distribution. From the high statistics COMPASS data on oppositely charged hadron-pair production we have investigated for the first time the dependence of these three asymmetries on the difference of the azimuthal angles of the two hadrons. The similarity of transversity induced single and di-hadron asymmetries is discussed. A new analysis of the data allows to establish quantitative relationships among them, providing for the first time strong experimental indication that the underlying fragmentation mechanisms are all driven by a common physical process.Comment: 6 figure

    Leading-order determination of the gluon polarisation from semi-inclusive deep inelastic scattering data

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    Using a novel analysis technique, the gluon polarisation in the nucleon is re-evaluated using the longitudinal double-spin asymmetry measured in the cross section of semi-inclusive single-hadron muoproduction with photon virtuality Q2>1 (GeV/c)2Q^2>1~({\rm GeV}/c)^2. The data were obtained by the COMPASS experiment at CERN using a 160 GeV/cc polarised muon beam impinging on a polarised 6^6LiD target. By analysing the full range in hadron transverse momentum pTp_{\rm T}, the different pTp_{\rm T}-dependences of the underlying processes are separated using a neural-network approach. In the absence of pQCD calculations at next-to-leading order in the selected kinematic domain, the gluon polarisation Δg/g\Delta g/g is evaluated at leading order in pQCD at a hard scale of μ2=Q2=3(GeV/c)2\mu^2= \langle Q^2 \rangle = 3 ({\rm GeV}/c)^2. It is determined in three intervals of the nucleon momentum fraction carried by gluons, xgx_{\rm g}, covering the range 0.04 ⁣< ⁣xg ⁣< ⁣0.280.04 \!<\! x_{ \rm g}\! <\! 0.28~ and does not exhibit a significant dependence on xgx_{\rm g}. The average over the three intervals, Δg/g=0.113±0.038(stat.)±0.036(syst.)\langle \Delta g/g \rangle = 0.113 \pm 0.038_{\rm (stat.)}\pm 0.036_{\rm (syst.)} at xg0.10\langle x_{\rm g} \rangle \approx 0.10, suggests that the gluon polarisation is positive in the measured xgx_{\rm g} range.Comment: 14 pages, 6 figure
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