510 research outputs found

    Charge-exchange processes of hydrogen ions with Hg atoms at keV energies

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    A search for the production of the 2p2 3Pe state of H- has been made by crossing a H-(1s2) ion beam of energies E\u3c140 keV with a thermal Hg beam inside a static electric field. The formation of\u3eH-(2p2) ions and their subsequent decay to neutral H(1s) results in a feature on the angular distribution of the neutral particles produced in electron loss of the ground-state H-(1s2) ions. The absence of such a feature sets an upper limit of 10-20 cm2 to the cross section for formation of the 2p2 3Pe state. Differential (with respect to angle) charge-transfer cross sections for scattering in the angular range 3Ā°\u3c\u3c15Ā°as well as the small-angle forward cross sections 10 and -10 for hydrogen ions passing through Hg vapor are presented. Ā© 1985 The American Physical Society

    Associations between Source-Specific Particulate Matter and Respiratory Infections in New York State Adults

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    The response of respiratory infections to source-specific particulate matter (PM) is an area of active research. Using source-specific PM2.5 concentrations at six urban sites in New York State, a case-crossover design, and conditional logistic regression, we examined the association between source-specific PM and the rate of hospitalizations and emergency department (ED) visits for influenza or culture-negative pneumonia from 2005 to 2016. There were at most N = 14 764 influenza hospitalizations, N = 57 522 influenza ED visits, N = 274 226 culture-negative pneumonia hospitalizations, and N = 113 997 culture-negative pneumonia ED visits included in our analyses. We separately estimated the rate of respiratory infection associated with increased concentrations of source-specific PM2.5, including secondary sulfate (SS), secondary nitrate (SN), biomass burning (BB), pyrolyzed organic carbon (OP), road dust (RD), residual oil (RO), diesel (DIE), and spark ignition vehicle emissions (GAS). Increased rates of ED visits for influenza were associated with interquartile range increases in concentrations of GAS (excess rate [ER] = 9.2%; 95% CI: 4.3%, 14.3%) and DIE (ER = 3.9%; 95% CI: 1.1%, 6.8%) for lag days 0-3. There were similar associations between BB, SS, OP, and RO, and ED visits or hospitalizations for influenza, but not culture-negative pneumonia hospitalizations or ED visits. Short-term increases in PM2.5 from traffic and other combustion sources appear to be a potential risk factor for increased rates of influenza hospitalizations and ED visits

    Changes in the hospitalization and ED visit rates for respiratory diseases associated with source-specific PM2.5 in New York State from 2005 to 2016

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    Prior work found increased rates for emergency department (ED) visits for asthma and hospitalizations for chronic obstructive pulmonary disease per unit mass of PM2.5 across New York State (NYS) during 2014ā€“2016 after significant reductions in ambient PM2.5 concentrations had occurred following implementation of various policy actions and major economic disruptions. The associations of source-specific PM2.5 concentrations with these respiratory diseases were assessed with a time-stratified case-cossover design and logistic regression models to identify the changes in the PM2.5 that have led to the apparently increased toxicity per unit mass. The rates of ED visits and hospitalizations for asthma and COPD associated with increases in source-specific PM2.5 concentrations in the prior 1, 4, and 7 days were estimated for 6 urban sites in New York State. Overall, there were similar numbers of significantly increased (n = 9) and decreased rates (n = 8) of respiratory events (asthma and COPD hospitalizations and ED visits) associated with increased source-specific PM2.5 concentrations in the previous 1, 4, and 7 days. Associations of source-specific PM2.5 concentrations with excess rates of hospitalizations for COPD for spark- and compression ignition vehicles increased in the 2014ā€“2016 period, but the values were not statistically significant. Other source types showed inconsistent patterns of excess rates. For asthma ED visits, only biomass burning and road dust showed consistent positive associations with road dust having significant values for most lag times. Secondary nitrate also showed significant positive associations with asthma ED visits in the AFTER period compared to no associations in the prior periods. These results suggest that the relationships of asthma and COPD exacerbation with source-specific PM2.5 are not well defined and further work will be needed to determine the causes of the apparent increases in the per unit mass toxicity of PM2.5 in New York State in the 2014-16 period

    Associations between serum taurine concentrations in mothers and neonates and the children's anthropometrics and early neurodevelopment:Results from the Seychelles Child Development Study, Nutrition Cohort 2

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    Background: High concentrations of taurine are present in the developing human brain and maternal breast milk. Taurine is thought to influence fetal growth and brain development based on experimental rodent studies. As fish is an important dietary source of taurine, we investigated associations between taurine concentrations and child outcomes in a high fish consuming population. Objective: To examine associations between maternal and cord serum taurine concentrations and birth anthropometric measures and cognitive development in children at 20 months of age. Methods: Pregnant women were recruited between 2008 and 2011 as part of Nutrition Cohort 2 (NC2) of the Seychelles Child Development Study (SCDS). Maternal taurine serum concentrations were measured at 28 weekā€™s gestation and in cord serum. Child weight, length and head circumference were measured at birth and neurodevelopment was assessed using Bayley Scales of Infant Development II (BSID-II) at 20 months of age. Associations between taurine status, birth measures and neurodevelopmental outcomes were examined (n = 300) using regression models and adjusted for relevant covariates. Results: Mean (SD) maternal and cord taurine concentrations were 124.9 (39.2) Āµmol/L (range 28.2ā€“253.9 Āµmol/ L) and 187.6 (60.0) Āµmol/L (range 55.0ā€“417.4 Āµmol/L) respectively. We found no associations between maternal taurine concentrations and child anthropometric and neurodevelopmental measures (weight Ī² = āˆ’ 0.001, SE=0.001; length Ī² = āˆ’ 0.006, SE=0.006; head circumference Ī² = āˆ’ 0.002, SE=0.002; MDI Ī² = āˆ’ 0.005, SE=0.015; PDI Ī² = āˆ’ 0.004, SE=0.016; all P > 0.05), or between cord taurine concentrations and outcomes (weight Ī² = āˆ’ 0.001, SE<0.000; length Ī² = āˆ’ 0.001, SE=0.004; head circumference Ī² < 0.000, SE=0.002; MDI Ī² = 0.004, SE=0.010; PDI Ī² = āˆ’ 0.015, SE=0.012; all P > 0.05). Conclusion: The Seychellois population have high maternal and cord taurine concentrations owing to their high fish intake and may be considered taurine replete compared to individuals who consume a Westernised diet. This high taurine status may explain why there were no significant associations between maternal and cord taurine concentrations and outcomes after adjusting for covariates

    Calculation of the Electron Self Energy for Low Nuclear Charge

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    We present a nonperturbative numerical evaluation of the one-photon electron self energy for hydrogenlike ions with low nuclear charge numbers Z=1 to 5. Our calculation for the 1S state has a numerical uncertainty of 0.8 Hz for hydrogen and 13 Hz for singly-ionized helium. Resummation and convergence acceleration techniques that reduce the computer time by about three orders of magnitude were employed in the calculation. The numerical results are compared to results based on known terms in the expansion of the self energy in powers of (Z alpha).Comment: 10 pages, RevTeX, 2 figure

    Extramitral Valvular Cardiac Involvement in Patients With Significant Secondary Mitral Regurgitation

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    Patients with secondary mitral regurgitation (SMR) often have extramitral valve cardiac involvement, which can influence the prognosis. SMR can be defined according to groups of extramitral valve cardiac involvement. The prognostic implications of such groups in patients with moderate and severe SMR (significant SMR) are unknown. A total of 325 patients with significant SMR were classified according to the extent of cardiac involvement on echocardiography: left ventricular involvement (group 1), left atrial involvement (group 2), tricuspid valve and pulmonary artery vasculature involvement (group 3), or right ventricular involvement (group 4). The primary end point was all-cause mortality. The prevalence of each cardiac involvement group was 17% in group 1, 12% in group 2, 23% in group 3%, and 48% in group 4. Group 3 and group 4 were independently associated with all-cause mortality (hazard ratio 1.794, 95% confidence interval 1.067 to 3.015, p = 0.027 and hazard ratio 1.857, 95% confidence interval 1.145 to 3.012, p = 0.012, respectively). In conclusion, progressive extramitral valve cardiac involvement (group 3 and group 4) was independently associated with all-cause mortality in patients with significant SMR.</p

    Electron Self Energy for the K and L Shell at Low Nuclear Charge

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    A nonperturbative numerical evaluation of the one-photon electron self energy for the K- and L-shell states of hydrogenlike ions with nuclear charge numbers Z=1 to 5 is described. Our calculation for the 1S state has a numerical uncertainty of 0.8 Hz in atomic hydrogen, and for the L-shell states (2S and 2P) the numerical uncertainty is 1.0 Hz. The method of evaluation for the ground state and for the excited states is described in detail. The numerical results are compared to results based on known terms in the expansion of the self energy in powers of (Z alpha).Comment: 21 pages, RevTeX, 5 Tables, 6 figure

    Using the Autism-Spectrum Quotient to Discriminate Autism Spectrum Disorder from ADHD in Adult Patients With and Without Comorbid Substance Use Disorder

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    It is unknown whether the Autism-spectrum quotient (AQ) can discriminate between Autism Spectrum Disorder (ASD) and Attention Deficit and Hyperactivity Disorder (ADHD) with or without comorbid Substance Use Disorder (SUD). ANOVAā€™s were used to analyse the mean AQ (sub)scores of 129 adults with ASD or ADHD. We applied receiver operating characteristic (ROC) computations to assess discriminant power. All but one of the mean AQ (sub)scores were significantly higher for adults with ASD compared to those with ADHD. The SUD status in general was not significantly associated with AQ (sub)scores. On the Social Skills subscale patients with ASD and comorbid SUD showed less impairment than those without SUD. The cut-off score 26 yielded 73% correct classifications. The clinical use of the AQ in differentiating between ASD and ADHD is limited
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