Resonance scattering and singularities of the scattering function

Recent studies of transport phenomena with complex potentials are explained by generic square root singularities of spectrum and eigenfunctions of non-Hermitian Hamiltonians. Using a two channel problem we demonstrate that such singularities produce a significant effect upon the pole behaviour of the scattering matrix, and more significantly upon the associated residues. This mechanism explains why by proper choice of the system parameters the resonance cross section is increased drastically in one channel and suppressed in the other channel.Comment: 4 pages, 3 figure

Life-Course Neighborhood Socioeconomic Status and Cardiovascular Events in Black and White Adults in the Atherosclerosis Risk in Communities Study

It has been reported that residents of low–socioeconomic-status (SES) neighborhoods have a higher risk of developing cardiovascular disease (CVD). However, most of the previous studies focused on 1-time measurement of neighborhood SES in middle-to-older adulthood and lacked demographic diversity to allow for comparisons across different race/ethnicity and sex groups. We examined neighborhood SES in childhood and young, middle, and older adulthood in association with CVD risk among Black and White men and women in the Atherosclerosis Risk in Communities Study (1996–2019). We found that lower neighborhood SES in young, middle, and older adulthood, but not in childhood, was associated with a higher risk of CVD later in life. When compared with the highest quartile, the lowest quartile of neighborhood SES in young, middle, and older adulthood was associated with 18% (hazard ratio (HR) = 1.18, 95% confidence interval (CI): 1.02, 1.36), 21% (HR = 1.21, 95% CI: 1.04, 1.39), and 12% (HR = 1.12, 95% CI: 0.99, 1.26) increases in the hazard of total CVD, respectively. The association between lower neighborhood SES in older adulthood and higher CVD hazard was particularly strong among Black women. Our study findings support the role of neighborhood SES in cardiovascular health in both Black and White adults

Associations of leisure-time physical activity and television viewing with life expectancy cancer-free at age 50: The ARIC study

Background: Physical activity has been associated with longer chronic disease-free life expectancy, but specific cancer types have not been investigated. We examined whether leisure-time moderate- to-vigorous physical activity (LTPA) and television (TV) viewing were associated with life expectancy cancer-free. Methods: We included 14,508 participants without a cancer history from the Atherosclerosis Risk in Communities (ARIC) study. We used multistate survival models to separately examine associations of LTPA (no LTPA, <median, ≥median) and TV viewing (seldom/never, sometimes, often/very often) with life expectancy cancer-free at age 50 from invasive colorectal, lung, prostate, and postmenopausal breast cancer. Models were adjusted for age, gender, race, ARIC center, education, smoking, and alcohol intake. Results: Compared with no LTPA, participants who engaged in LTPA ≥median had a greater life expectancy cancer-free from colorectal [men-2.2 years (95% confidence interval (CI), 1.7-2.7), women-2.3 years (95% CI, 1.7-2.8)], lung [men-2.1 years (95% CI, 1.5-2.6), women-2.1 years (95% CI, 1.6-2.7)], prostate [1.5 years (95% CI, 0.8-2.2)], and postmenopausal breast cancer [2.4 years (95% CI, 1.4-3.3)]. Compared with watching TV often/very often, participants who seldom/never watched TV had a greater colorectal, lung, and postmenopausal breast cancer-free life expectancy of ∼1 year. Conclusions: Participating in LTPA was associated with longer life expectancy cancer-free from colorectal, lung, prostate, and postmenopausal breast cancer. Viewing less TV was associated with more years lived cancer-free from colorectal, lung, and postmenopausal breast cancer. Impact: Increasing physical activity and reducing TV viewing may extend the number of years lived cancer-free

Use of troponins in the classification of myocardial infarction from electronic health records. The Atherosclerosis Risk in Communities (ARIC) Study

Objective: Electronic health record (EHR) data are underutilized for abstracting classification criteria for heart disease. We compared extraction of EHR data on troponin I and T levels with human abstraction. Methods: Using EHR for hospitalizations identified through the Atherosclerosis Risk in Communities (ARIC) Study in four US hospitals, we compared blood levels of troponins I and T extracted from EHR structured data elements with levels obtained through data abstraction by human abstractors to 3 decimal places. Observations were divided randomly 50/50 into training and validation sets. Bayesian multilevel logistic regression models were used to estimate agreement by hospital in first and maximum troponin levels, troponin assessment date, troponin upper limit of normal (ULN), and classification of troponin levels as normal (2× ULN), or missing. Results: Estimated overall agreement in first measured troponin level in the validation data was 88.2% (95% credible interval: 65.0%-97.5%) and 95.5% (91.2-98.2%) for the maximum troponin level observed during hospitalization. The largest variation in probability of agreement was for first troponin measured, which ranged from 66.4% to 95.8% among hospitals. Conclusion: Extraction of maximum troponin values during a hospitalization from EHR structured data is feasible and accurate

Contribution of medications and risk factors to QTc interval lengthening in the atherosclerosis risk in communities (ARIC) study

Rationale, aims, and objectives: Prolongation of the corrected QT (QTc) interval is associated with increased morbidity and mortality. The association between QTc interval–prolonging medications (QTPMs) and risk factors with magnitude of QTc interval lengthening is unknown. We examined the contribution of risk factors alone and in combination with QTPMs to QTc interval lengthening. Method: The Atherosclerosis Risk in Communities study assessed 15 792 participants with a resting, standard 12-lead electrocardiogram and ≥1 measure of QTc interval over 4 examinations at 3-year intervals (1987-1998). From 54 638 person-visits, we excluded participants with QRS ≥ 120 milliseconds (n = 2333 person-visits). We corrected the QT interval using the Bazett and Framingham formulas. We examined QTc lengthening using linear regression for 36 602 person-visit observations for 14 160 cohort members controlling for age ≥ 65 years, female sex, left ventricular hypertrophy, QTc > 500 milliseconds at the prior visit, and CredibleMeds categorized QTPMs (Known, Possible, or Conditional risk). We corrected standard errors for repeat observations per person. Results: Eighty percent of person-visits had at least one risk factor for QTc lengthening. Use of QTPMs increased over the 4 visits from 8% to 17%. Among persons not using QTPMs, history of prolonged QTc interval and female sex were associated with the greatest QTc lengthening, 39 and 12 milliseconds, respectively. In the absence of risk factors, Known QTPMs and ≥2 QTPMs were associated with modest but greater QTc lengthening than Possible or Conditional QTPMs. In the presence of risk factors, ≥2 QTPM further increased QTc lengthening. In combination with risk factors, the association of all QTPM categories with QTc lengthening was greater than QTPMs alone. Conclusion: Risk factors, particularly female sex and history of prolonged QTc interval, have stronger associations with QTc interval lengthening than any QTPM category alone. All QTPM categories augmented QTc interval lengthening associated with risk factors

Orthostatic hypotension and novel blood pressure-associated gene variants: Genetics of Postural Hemodynamics (GPH) Consortium

Aims Orthostatic hypotension (OH), an independent predictor of mortality and cardiovascular events, strongly correlates with hypertension. Recent genome-wide studies have identified new loci influencing blood pressure (BP) in populations, but their impact on OH remains unknown. Methods and resultsA total of 38 970 men and women of European ancestry from five population-based cohorts were included, of whom 2656 (6.8) met the diagnostic criteria for OH (systolic/diastolic BP drop <20/10 mmHg within 3 min of standing). Thirty-one recently discovered BP-associated single nucleotide polymorphisms (SNPs) were examined using an additive genetic model and the major allele as referent. Relations between OH, orthostatic systolic BP response, and genetic variants were assessed by inverse variance-weighted meta-analysis. We found Bonferroni adjusted (P < 0.0016) significant evidence for association between OH and the EBF1 locus (rs11953630, per-minor-allele odds ratio, 95 confidence interval: 0.90, 0.850.96; P=0.001), and nominal evidence (P < 0.05) for CYP17A1 (rs11191548: 0.85, 0.750.95; P=0.005), and NPR3-C5orf23 (rs1173771: 0.92, 0.870.98; P=0.009) loci. Among subjects not taking BP-lowering drugs, three SNPs within the NPPA/NPPB locus were nominally associated with increased risk of OH (rs17367504: 1.13, 1.021.24; P=0.02, rs198358: 1.10, 1.011.20; P=0.04, and rs5068: 1.22, 1.041.43; P=0.01). Moreover, an ADM variant was nominally associated with continuous orthostatic systolic BP response in the adjusted model (P=0.04). ConclusionThe overall association between common gene variants in BP loci and OH was generally weak and the direction of effect inconsistent with resting BP findings. These results suggest that OH and resting BP share few genetic components

Low Q^2 Jet Production at HERA and Virtual Photon Structure

The transition between photoproduction and deep-inelastic scattering is investigated in jet production at the HERA ep collider, using data collected by the H1 experiment. Measurements of the differential inclusive jet cross-sections dsigep/dEt* and dsigmep/deta*, where Et* and eta* are the transverse energy and the pseudorapidity of the jets in the virtual photon-proton centre of mass frame, are presented for 0 < Q2 < 49 GeV2 and 0.3 < y < 0.6. The interpretation of the results in terms of the structure of the virtual photon is discussed. The data are best described by QCD calculations which include a partonic structure of the virtual photon that evolves with Q2.Comment: 20 pages, 5 Figure

Hadron Production in Diffractive Deep-Inelastic Scattering

Characteristics of hadron production in diffractive deep-inelastic positron-proton scattering are studied using data collected in 1994 by the H1 experiment at HERA. The following distributions are measured in the centre-of-mass frame of the photon dissociation system: the hadronic energy flow, the Feynman-x (x_F) variable for charged particles, the squared transverse momentum of charged particles (p_T^{*2}), and the mean p_T^{*2} as a function of x_F. These distributions are compared with results in the gamma^* p centre-of-mass frame from inclusive deep-inelastic scattering in the fixed-target experiment EMC, and also with the predictions of several Monte Carlo calculations. The data are consistent with a picture in which the partonic structure of the diffractive exchange is dominated at low Q^2 by hard gluons.Comment: 16 pages, 6 figures, submitted to Phys. Lett.

Energy Flow in the Hadronic Final State of Diffractive and Non-Diffractive Deep-Inelastic Scattering at HERA

An investigation of the hadronic final state in diffractive and non--diffractive deep--inelastic electron--proton scattering at HERA is presented, where diffractive data are selected experimentally by demanding a large gap in pseudo --rapidity around the proton remnant direction. The transverse energy flow in the hadronic final state is evaluated using a set of estimators which quantify topological properties. Using available Monte Carlo QCD calculations, it is demonstrated that the final state in diffractive DIS exhibits the features expected if the interaction is interpreted as the scattering of an electron off a current quark with associated effects of perturbative QCD. A model in which deep--inelastic diffraction is taken to be the exchange of a pomeron with partonic structure is found to reproduce the measurements well. Models for deep--inelastic $ep$ scattering, in which a sizeable diffractive contribution is present because of non--perturbative effects in the production of the hadronic final state, reproduce the general tendencies of the data but in all give a worse description.Comment: 22 pages, latex, 6 Figures appended as uuencoded fil

A Search for Selectrons and Squarks at HERA

Data from electron-proton collisions at a center-of-mass energy of 300 GeV are used for a search for selectrons and squarks within the framework of the minimal supersymmetric model. The decays of selectrons and squarks into the lightest supersymmetric particle lead to final states with an electron and hadrons accompanied by large missing energy and transverse momentum. No signal is found and new bounds on the existence of these particles are derived. At 95% confidence level the excluded region extends to 65 GeV for selectron and squark masses, and to 40 GeV for the mass of the lightest supersymmetric particle.Comment: 13 pages, latex, 6 Figure