Pramita Bagchi

Ruhr University Bochum | RUB · Arbeitsgruppe Mathematische Statistik

Background: Infection rates are high in heart transplant (HT) patients due to the need for immunosuppressive medication. MicroRNAs (miR) are non-coding RNAs, that regulate gene expression and are promising biomarkers for identifying patients at risk for infection. Hypothesis: MiR profiles can identify HT patients who are at increased risk for devel...

This article investigates some nice properties of the least squares estimator of mul-tivariate isotonic regression function (denoted as LSEMIR), when the model is mis-specified, and the errors are β-mixing stationary random variables. Under mild conditions, it is observed that the least squares estimator converges uniformly to a certain monotone fu...

Background Little is known about sex-related differences in outcomes of patients with cardiogenic shock (CS) treated within a standardized team-based approach (STBA). Methods We evaluated 520 consecutive patients (151 women and 369 men) with CS due to acute myocardial infarction (AMI) and heart failure (HF) in a single-center registry (January 201...

Background: Cardiac magnetic resonance imaging (CMR) determines the extent of interstitial fibrosis, measured by increased extracellular volume (ECV), and replacement fibrosis with late gadolinium myocardial enhancement (LGE). Despite advances in detection, the pathophysiology of subclinical myocardial fibrosis is incompletely understood. Targeted...

BACKGROUND Chinese American family caregivers of persons with dementia experience high rates of psychosocial distress and adverse health outcomes. Due to their immigrant and minority status, they face substantial obstacles to care and support, including stigma and misperception of dementia, limited knowledge and use of welfare and services, and poo...

Background: Noninvasive monitoring of heart allograft health is important to improve clinical outcomes. MicroRNAs (miRs) are promising biomarkers of cardiovascular disease and limited studies suggest they can be used to noninvasively diagnose acute heart transplant rejection. Methods: The Genomic Research Alliance for Transplantation (GRAfT) is...

Background: Little is known about clinical characteristics, hospital course, and longitudinal outcomes of patients with cardiogenic shock (CS) related to heart failure (HF-CS) compared to acute myocardial infarction (AMI; CS related to AMI [AMI-CS]). Methods: We examined in-hospital and 1-year outcomes of 520 (219 AMI-CS, 301 HF-CS) consecutive...

Purpose Recently, protein biomarkers such as N-terminal B-type natriuretic peptide (NT-proBNP), and growth differentiation factor-15 (GDF-15) have been shown to predict risk for gastrointestinal bleeding (GIB) and stroke in atrial fibrillation. This study aims to assess the validity of these biomarkers in predicting the incidence of stroke or GIB i...

Purpose Non-invasive monitoring of heart allograft health is an important clinical goal and circulating microRNAs (miRs) have been associated with acute rejection in limited studies. Methods The Genomic Research Alliance for Transplantation (GRAfT) is a multicenter prospective study. Patients with no history of rejection after transplant were sele...

Objective In United States, Asian Americans are 10 times more likely to have hepatitis B virus (HBV) infection than Whites. Asian immigrants with limited English proficiency face extra barriers to HBV screening and many are unaware of the infectious status. This study aimed to evaluate a social media-based intervention to promote HBV screening and...

Aim The association of subclinical atherosclerotic disease in the coronary arteries and thoracic aorta with incident peripheral arterial disease (PAD) is unknown. We investigated the association between coronary artery calcium score (CACs) and thoracic aortic calcium score (TACs) with incident clinical and subclinical PAD. Methods and results The...

Introduction: Historically, studies have focused on short-term morbidity and mortality associated with cardiogenic shock (CS). Little is known about post discharge outcomes following acute myocardial infarction (AMI-CS) as compared to acute decompensated heart failure (ADHF-CS). Methods: We examined 520 (219 AMI-CS, 301 ADHF-CS) consecutive patient...

We propose a new test to validate the assumption of homoscedasticity in a functional linear model. We consider a minimum distance measure of heteroscedasticity in functional data, which is zero in the case where the variance is constant and positive otherwise. We derive an explicit form of the measure, propose an estimator for the quantity, and sho...

This paper reports on our efforts to collect daily COVID-19-related symptoms for a large public university population, as well as study relationship between reported symptoms and individual movements. We developed a set of tools to collect and integrate individual-level data. COVID-19-related symptoms are collected using a self-reporting tool initi...

The frequency-domain properties of nonstationary functional time series often contain valuable information. These properties are characterized through its time-varying power spectrum. Practitioners seeking low-dimensional summary measures of the power spectrum often partition frequencies into bands and create collapsed measures of power within band...

Introduction: The Sequential Organ Failure Assessment (SOFA) score predicts intensive care unit (ICU) mortality within a medical ICU population but utility of the SOFA score in the contemporary cardiac ICU (CICU) is unclear. Methods: Data from consecutive patients with primary cardiac (PC) and non-cardiac (PNC) disease admitted to the CICU at a ter...

Introduction: Coronary artery calcium score (CACs) measured by non-contrast cardiac CT has a strong correlation with coronary atherosclerotic burden. Although CACs predicts incident coronary heart disease, its gender-specific association with incident peripheral artery disease (PAD) is not clear. Methods: The multi-ethnic study of atherosclerosis (...

Funding information SFB 823, Project C1 Consider the problem of pointwise estimation of in a multi-variate isotonic regression model = (1 , … , ,) + , where is the response variable, is an unknown non-parametric regression function, which is isotonic with respect to each component , and is the error term. In this article, we investigate the behavio...

Using latent class analysis, we previously identified three acculturation strategies employed by South Asian immigrants in the US. Members of the Separation class showed a preference for South Asian culture over US culture, while members of the Assimilation class showed a preference for US culture, and those in the Integration class showed a simila...

Consider the problem of pointwise estimation of f in a multiple isotonic regression model Z = f (X1,. .. , X d) + , where Z is the response variable, f is an unknown non-parametric regression function , which is isotonic with respect to each component, and is the error term. In this article, we investigate the behaviour of the least square estimato...

The assumption of separability is a simplifying and very popular assumption in the analysis of spatio-temporal or hypersurface data structures. It is often made in situations where the covariance structure cannot be easily estimated, for example because of a small sample size or because of computational storage problems. In this paper we propose a...

In the past, epidemiologic research on acculturation and health has been criticized for its conceptual ambiguity and simplistic measurement approaches. This study applied a widely-used theoretical framework from cross-cultural psychology to identify acculturation strategies among South Asian immigrants in the US and to examine sociodemographic corr...

We propose a new procedure for white noise testing of a functional time series. Our approach is based on an explicit representation of the $L^2$-distance between the spectral density operator and its best ($L^2$-)approximation by a spectral density operator corresponding to a white noise process. The estimation of this distance can be easily accomp...

We propose a new procedure for white noise testing of a functional time series. Our approach is based on an explicit representation of the $L^2$-distance between the spectral density operator and its best ($L^2$-)approximation by a spectral density operator corresponding to a white noise process. The estimation of this distance can be easily accomp...

We introduce new point-wise confidence interval estimates for monotone functions observed with additive, dependent noise. Our methodology applies to both short- and long-range dependence regimes for the errors. The interval estimates are obtained via the method of inversion of certain discrepancy statistics. This approach avoids the estimation of n...

The work discusses different non-standard problems under different types of short and long range dependence. In the first part we introduce new point-wise confidence interval estimates for monotone functions observed with additive and dependent noise. Existence of such monotone trend is quite common in time series data. We study both short- and lo...

AimsTo examine the associations between endogenous sex steroid hormones (oestradiol, testosterone and sex hormone-binding globulin) with diabetes risk in a South-Asian population living in the USA.Methods We used data from the Metabolic Syndrome and Atherosclerosis in South-Asians Living in America pilot study. The analytical sample included 60 wom...

We focus on the problem estimating a monotone trend function under additive and dependent noise. New point-wise confidence interval estimators under both short- and long-range dependent errors are introduced and studied. These intervals are obtained via the method of inversion of certain discrepancy statistics arising in hypothesis testing problems...

For secure communications in wireless sensor network in adversarial conditions, one way is providing keys to sensor nodes before deployment. Two sensor nodes can communicate provided they have at least one key in common or there is a path between the two nodes where each pair of neighboring nodes on this path has at least one key in common. However...