Semiparametric Bayesian analysis of gene-environment interactions with error in measurement of environmental covariates and missing genetic data

Case-control studies are widely used to detect geneenvironment interactions in the etiology of complex diseases. Many variables that are of interest to biomedical researchers are difficult to measure on an individual level, e.g. nutrient intake, cigarette smoking exposure, long-term toxic exposure. Measurement error causes bias in parameter estimates, thus masking key features of data and leading to loss of power and spurious/masked associations. We develop a Bayesian methodology for analysis of case-control studies for the case when measurement error is present in an environmental covariate and the genetic variable has missing data. This approach offers several advantages. It allows prior information to enter the model to make estimation and inference more precise. The environmental covariates measured exactly are modeled completely nonparametrically. Further, information about the probability of disease can be incorporated in the estimation procedure to improve quality of parameter estimates, what cannot be done in conventional case-control studies. A unique feature of the procedure under investigation is that the analysis is based on a pseudo-likelihood function therefore conventional Bayesian techniques may not be technically correct. We propose an approach using Markov Chain Monte Carlo sampling as well as a computationally simple method based on an asymptotic posterior distribution. Simulation experiments demonstrated that our method produced parameter estimates that are nearly unbiased even for small sample sizes. An application of our method is illustrated using a population-based case-control study of the association between calcium intake with the risk of colorectal adenoma development

Statistical forecasting of panel data based on state space models

Panel (or longitudinal) data describes a set of objects which are observed during certain period of time, so they consist of repeated observations of the same objects in sequential time periods. The following examples of panel data can be mentioned: annual household studies, monthly performance indicators for economic institutions and many others. In this study we provide another approach to forecasting cross-sectional data based on state space models together with Kalman filtering procedure

Самостоятельная работа студентов как фактор самообразования и развития познавательных способностей личности

The main purpose of the paper is to show the role of independent work for provision ,of high student’s progress in studies and his self-education as a demand of permanent perfection of the experience. The paper may be used for organization of teaching and educational work with students. Основная цель статьи - показать роль самостоятельной работы в обеспечении высокой успеваемости студента и его самообразовании как потребности в постоянном совершенствовании опыта. Может быть использована в организации учебной и воспитательной работы со студентами

Random raman fiber laser based on a twin-core fiber with FBGs inscribed by femtosecond radiation

Narrowband Raman lasing in a polarization-maintaining two-core fiber (TCF) is demonstrated. Femtosecond point-by-point inscription of fiber Bragg gratings (FBGs) in individual cores produces a half-open cavity with random distributed feedback. The laser linewidth in the cavity with a single FBG inscribed in one core of the TCF reduced by ∼2 times with respect to the cavity with a fiber loop mirror. It is shown that the inscription of two FBGs in different cores leads to the formation of a Michelson-type interferometer, leading to the modulation of generation spectra near threshold. This technique offers new possibilities for spectral filtering or multi-wavelength generation

Urban Public Transport, Logistic Approach to the Transport Management

In modern condition further development and improvement of economy are based on progressive transport maintenance

Urban Public Transport, Logistic Approach to the Transport Management

In modern condition further development and improvement of economy are based on progressive transport maintenance

Doctrinal comprehension of cyber terrorism in the context of intensive development of information and communication technologies in the modern world

The paper examines the doctrinal aspects of understanding cyber terrorism as an atypical manifestation (form) of traditional terrorism updated in light of the intensive development and widespread dissemination of information and communication technologies (ICT) in the modern world. The conclusion is substantiated that cyber terrorism is a conceptually relevant concept, which is perceived either as a method of committing a terrorist act (reduced understanding), or as any crimes of a terrorist nature that are committed using information and communication technologies (broad understanding).У статті розглядаються доктринальні аспекти розуміння кібертероризму як нетипового прояву (форми) традиційного тероризму, оновленого у світлі інтенсивного розвитку та широкого розповсюдження інформаційно-комунікаційних технологій (ІКТ) у сучасному світі. Обґрунтовано висновок, що кібертероризм - це концептуально відповідне поняття, яке сприймається або як метод вчинення терористичного акту (знижене розуміння), або як будь-які злочини терористичного характеру, що вчиняються з використанням інформаційно-комунікаційних технологій (широке розуміння).В статье рассматриваются доктринальные аспекты понимания кибертерроризма как нетипичного проявления (формы) традиционного терроризма, обновленного в свете интенсивного развития и широкого распространения информационно-коммуникационных технологий (ИКТ) в современном мире. Обоснован вывод, что кибертерроризм — это концептуально соответствующее понятие, воспринимается либо как метод совершения террористического акта (пониженное понимание), или как любые преступления террористического характера, совершаемых с использованием информационно-коммуникационных технологий (широкое понимание)

Frontal white matter tracts sustaining speech production in primary progressive aphasia

In primary progressive aphasia (PPA), speech and language difficulties are caused by neurodegeneration of specific brain networks. In the nonfluent/agrammatic variant (nfvPPA), motor speech and grammatical deficits are associated with atrophy in a left fronto-insular-striatal network previously implicated in speech production. In vivo dissection of the crossing white matter (WM) tracts within this "speech production network" is complex and has rarely been performed in health or in PPA. We hypothesized that damage to these tracts would be specific to nfvPPA and would correlate with differential aspects of the patients' fluency abilities. We prospectively studied 25 PPA and 21 healthy individuals who underwent extensive cognitive testing and 3 T MRI. Using residual bootstrap Q-ball probabilistic tractography on high angular resolution diffusion-weighted imaging (HARDI), we reconstructed pathways connecting posterior inferior frontal, inferior premotor, insula, supplementary motor area (SMA) complex, striatum, and standard ventral and dorsal language pathways. We extracted tract-specific diffusion tensor imaging (DTI) metrics to assess changes across PPA variants and perform brain-behavioral correlations. Significant WM changes in the left intrafrontal and frontostriatal pathways were found in nfvPPA, but not in the semantic or logopenic variants. Correlations between tract-specific DTI metrics with cognitive scores confirmed the specific involvement of this anterior-dorsal network in fluency and suggested a preferential role of a posterior premotor-SMA pathway in motor speech. This study shows that left WM pathways connecting the speech production network are selectively damaged in nfvPPA and suggests that different tracts within this system are involved in subcomponents of fluency. These findings emphasize the emerging role of diffusion imaging in the differential diagnosis of neurodegenerative diseases

The effect of feedback to general practitioners on quality of care for people with type 2 diabetes. A systematic review of the literature

<p>Abstract</p> <p>Background</p> <p>There have been numerous efforts to improve and assure the quality of treatment and follow-up of people with Type 2 diabetes (PT2D) in general practice. Facilitated by the increasing usability and validity of guidelines, indicators and databases, feedback on diabetes care is a promising tool in this aspect. Our goal was to assess the effect of feedback to general practitioners (GPs) on the quality of care for PT2D based on the available literature.</p> <p>Methods</p> <p>Systematic review searches were conducted using October 2008 updates of Medline (Pubmed), Cochrane library and Embase databases. Additional searches in reference lists and related articles were conducted. Papers were included if published in English, performed as randomized controlled trials, studying diabetes, having general practice as setting and using feedback to GPs on diabetes care. The papers were assessed according to predefined criteria.</p> <p>Results</p> <p>Ten studies complied with the inclusion criteria. Feedback improved the care for PT2D, particularly process outcomes such as foot exams, eye exams and Hba1c measurements. Clinical outcomes like lowering of blood pressure, Hba1c and cholesterol levels were seen in few studies. Many process and outcome measures did not improve, while none deteriorated. Meta analysis was unfeasible due to heterogeneity of the studies included. Two studies used electronic feedback.</p> <p>Conclusion</p> <p>Based on this review, feedback seems a promising tool for quality improvement in diabetes care, but more research is needed, especially of electronic feedback.</p