Semiparametric Regression for Periodic Longitudinal Hormone Data from Multiple Menstrual Cycles

We consider Semiparametric regression for periodic longitudinal data. Parametric fixed effects are used to model the covariate effects and a periodic nonparametric smooth function is used to model the time effect. The within–subject correlation is modeled using subject-specific random effects and a random stochastic process with a periodic variance function. We use maximum penalized likelihood to estimate the regression coefficients and the periodic nonparametric time function, whose estimator is shown to be a periodic cubic smoothing spline. We use restricted maximum likelihood to simultaneously estimate the smoothing parameter and the variance components. We show that all model parameters can be easily obtained by fitting a linear mixed model. A common problem in the analysis of longitudinal data is to compare the time profiles of two groups, e.g., between treatment and placebo. We develop a scaled chi-squared test for the equality of two nonparametric time functions. The proposed model and the test are illustrated by analyzing hormone data collected during two consecutive menstrual cycles and their performance is evaluated through simulations.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/65472/1/j.0006-341X.2000.00031.x.pd

Linear mixed models with flexible distributions of random effects for longitudinal data.

SUMMARY. Normality of random effects is a routine assumption for the linear mixed model, but it may be unrealistic, obscuring important features of among-individual variation. We relax this assumption by approximating the random effects density by the seminonparameteric (SNP) representation of Gallant and Nychka (1987, Econometrics 55, 363-390), which includes normality as a special case and provides flexibility in capturing a broad range of nonnormal behavior, controlled by a user-chosen tuning parameter. An advantage is that the marginal likelihood may be expressed in closed form, so inference may be carried out using standard optimization techniques. We demonstrate that standard information criteria may be used to choose the tuning parameter and detect departures from normality, and we illustrate the approach via simulation and using longitudinal data from the Framingham study

Investigation of genetic diversity and population structure of common wheat cultivars in northern China using DArT markers

<p>Abstract</p> <p>Background</p> <p>In order to help establish heterotic groups of Chinese northern wheat cultivars (lines), Diversity arrays technology (DArT) markers were used to investigate the genetic diversity and population structure of Chinese common wheat (<it>Triticum aestivum </it>L.).</p> <p>Results</p> <p>In total, 1637 of 7000 DArT markers were polymorphic and scored with high confidence among a collection of 111 lines composed mostly of cultivars and breeding lines from northern China. The polymorphism information content (PIC) of DArT markers ranged from 0.03 to 0.50, with an average of 0.40, with P > 80 (reliable markers). With principal-coordinates analysis (PCoA) of DArT data either from the whole genome or from the B-genome alone, all lines fell into one of two major groups reflecting 1RS/1BL type (1RS/1BL and non-1RS/1BL). Evidence of geographic clustering of genotypes was also observed using DArT markers from the A genome. Cluster analysis based on the unweighted pair-group method with algorithmic mean suggested the existence of two subgroups within the non-1RS/1BL group and four subgroups within the 1RS/1BL group. Furthermore, analysis of molecular variance (AMOVA) revealed highly significant (<it>P </it>< 0.001) genetic variance within and among subgroups and among groups.</p> <p>Conclusion</p> <p>These results provide valuable information for selecting crossing parents and establishing heterotic groups in the Chinese wheat-breeding program.</p

Interpregnancy weight retention patterning in women who breastfed

This study compares weight change in lactating women with an 18-month interpregnancy interval with woman who also breastfed but did not have an immediate subsequent pregnancy. Cases were women who breastfed an index infant for 6 months and subsequently became pregnant within 18 months (cases = 25), and the controls also breastfed an index infant for 6 months but had no ensuing pregnancy (controls = 20) within 18 months. The pattern of postpartum weight retention following the initial pregnancy was not statistically different in cases compared to the controls. However, following their ensuing subsequent pregnancy, cases were 1.3 kg heavier than their average weight after their baseline pregnancy ( P = 0.02). The best predictor of this greater weight was their weight change during the interpregnancy interval ( P = 0.03). Total weight gain during the gestational period of the subsequent pregnancy was not associated with the greater weight following the subsequent pregnancy. Likewise, estimates of the amount of energy as calories or physical activity levels were not significant predictors of this greater weight following the subsequent pregnancy. These findings suggest that monitoring of postpartum weight, even in breastfeeding women, is essential. These findings indicate that breastfeeding women begin the next postpartum interval weighing more than the amount observed in the initial postpartum period. J. Matern.–Fetal Med. 7:89–94, 1998. © 1998 Wiley-Liss, Inc.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/35150/1/7_ftp.pd

Availability and trend of dissemination of cardiac rehabilitation in China: report from the multicenter national registration platform between 2012 and 2021

The study aimed to evaluate the current status of cardiac rehabilitation programs in China by registering and tracking patients undergoing CR programs in the database. Data were extracted from the online registry platform of the China Society of Cardiopulmonary Prevention and Rehabilitation from February 2012 to December 2021. Overall, data on 19,896 patients with cardiovascular diseases (CVDs) from 159 hospitals in 34 provinces of China were extracted. From a time point of view, the number of patients who had undergone CR and institutions that perform CR showed the first decline in 2009 and then increased until 2021. From a geographic point of view, the degree of participation varied greatly among regions, most of which were concentrated in eastern parts of China. A higher population of patients who underwent CR were male, aged less than 60 years, with low-a risk for coronary heart disease (CHD), and tended to choose the hospital-based CR program among all cases registered in the database. The top three diseases in the patients who participated in CR were CHD, hypertension, and metabolic syndrome (MS). Centers with CR were more likely to be tertiary-level hospitals. After adjusting for baseline values, there were significant differences in post-CR exercise capacity among the three groups (home-based CR group, hospital-based CR group, and hybrid CR group), which were in favor of the hybrid CR group compared with other groups. The underutilization of CR is a global issue, not just in China. Despite the number of CR programs showing an increasing trend in the past years, CR in China is still in the preliminary stage of development. Furthermore, the participation of CR in China shows wide diversity across geography, disease, age, sex, risk stratification, and hospital-level factors. These findings reinforce the importance of the implementation of effective measures to improve the participation, enrollment in, and uptake of cardiac rehabilitation

Optimal discrimination between quantum operations

In this paper, we address the problem of discriminating two given quantum operations. Firstly, based on the Bloch representation of single qubit systems, we give the exact minimum error probability of discriminating two single qubit quantum operations by unentangled input states. In particular, for the Pauli channels discussed in [Phys. Rev. A {\bf 71}, 062340 (2005)], we use a more intuitional and visual method to deal with their discrimination problem. Secondly, we consider the condition for perfect discrimination of two quantum operations. Specially, we get that two generalized Pauli channels are perfectly distinguishable if and only if their characteristic vectors are orthogonal.Comment: 6 pages (revtex4 version); comments are welcom

Genetic Variants at Newly Identified Lipid Loci Are Associated with Coronary Heart Disease in a Chinese Han Population

Recent genome-wide association studies (GWAS) have mapped several novel loci influencing blood lipid levels in Caucasians. We sought to explore whether the genetic variants at newly identified lipid-associated loci were associated with CHD susceptibility in a Chinese Han population. and 0.001, respectively).We identified two novel SNPs (rs599839 and rs16996148) at newly identified lipid-associated loci that were significantly associated with CHD susceptibility in a Chinese Han population

The pattern of late gadolinium enhancement by cardiac MRI in fulminant myocarditis and its prognostic implication: a two-year follow-up study

BackgroundMyocardial fibrosis, as quantified by late gadolinium enhancement (LGE) in cardiac magnetic resonance (CMR), provides valuable prognostic information for patients with myocarditis. However, due to the low incidence rate of fulminant myocarditis (FM) and accordingly small sample size, the knowledge about the role of LGE to patients with FM is limited.Methods and resultsA total of 44 adults with viral-FM receiving the Chinese treating regimen were included in this retrospective study. They were divided into the low LGE group and the high LGE group according to the ratio of LGE to left ventricular mass (LGE mass%). CMR exams and LGE were performed after hemodynamic assistance at discharge in all patients with FM. Routine echocardiography parameters and global longitudinal strain (GLS) at discharge and at 2-year follow-up were obtained and then compared. Both left ventricular ejection fraction (LVEF) and GLS showed no significant difference in both groups at discharge, whereas significant differences were observed at 2-year follow-up between two groups. Moreover, there were significant improvements of LVEF and GLS in the low LGE group, but not in the high LGE group during the 2-year period. Furthermore, LGE mass% was negatively correlated with GLS and LVEF.ConclusionsThere were two distinct forms of LGE presentation in patients with FM. Moreover, the cardiac function of patients with low LGE was significantly better than those with high LGE at 2-year follow-up. LGE mass% at discharge provided significant prognosis information about cardiac function of patients with FM