Search results for "statistical [methods]"
showing 10 items of 1664 documents
Cluster size distributions in particle systems with asymmetric dynamics
2001
We present exact and asymptotic results for clusters in the one-dimensional totally asymmetric exclusion process (TASEP) with two different dynamics. The expected length of the largest cluster is shown to diverge logarithmically with increasing system size for ordinary TASEP dynamics and as a logarithm divided by a double logarithm for generalized dynamics, where the hopping probability of a particle depends on the size of the cluster it belongs to. The connection with the asymptotic theory of extreme order statistics is discussed in detail. We also consider a related model of interface growth, where the deposited particles are allowed to relax to the local gravitational minimum.
Solid-solid phase transition in hard ellipsoids
2009
We present a computer simulation study of the crystalline phases of hard ellipsoids of revolution. A previous study [P. Pfleiderer and T. Schilling, Phys. Rev. E 75, 020402 (2007)]. showed that for aspect ratios a/bor=3 the previously suggested stretched-fcc phase [D. Frenkel and B. Mulder, Mol. Phys. 55, 1171 (1985)] is unstable with respect to a simple monoclinic phase with two ellipsoids of different orientations per unit cell (SM2). In order to study the stability of these crystalline phases at different aspect ratios and as a function of density we have calculated their free energies by thermodynamic integration. The integration path was sampled by an expanded ensemble method in which …
Thermalization of Levy flights: Path-wise picture in 2D
2013
We analyze two-dimensional (2D) random systems driven by a symmetric L\'{e}vy stable noise which, under the sole influence of external (force) potentials $\Phi (x) $, asymptotically set down at Boltzmann-type thermal equilibria. Such behavior is excluded within standard ramifications of the Langevin approach to L\'{e}vy flights. In the present paper we address the response of L\'{e}vy noise not to an external conservative force field, but directly to its potential $\Phi (x)$. We prescribe a priori the target pdf $\rho_*$ in the Boltzmann form $\sim \exp[- \Phi (x)]$ and next select the L\'evy noise of interest. Given suitable initial data, this allows to infer a reliable path-wise approxima…
Quantification of the heterogeneity of prognostic cellular biomarkers in ewing sarcoma using automated image and random survival forest analysis
2014
Driven by genomic somatic variation, tumour tissues are typically heterogeneous, yet unbiased quantitative methods are rarely used to analyse heterogeneity at the protein level. Motivated by this problem, we developed automated image segmentation of images of multiple biomarkers in Ewing sarcoma to generate distributions of biomarkers between and within tumour cells. We further integrate high dimensional data with patient clinical outcomes utilising random survival forest (RSF) machine learning. Using material from cohorts of genetically diagnosed Ewing sarcoma with EWSR1 chromosomal translocations, confocal images of tissue microarrays were segmented with level sets and watershed algorithm…
Ductal Carcinoma In Situ of the Breast: A Comparative Analysis of Histology, Nuclear Area, Ploidy, and Neovascularization Provides Differentiation Be…
2002
Ductal carcinoma in situ (DCIS) is a heterogeneous group of lesions that has been subdivided into three types: well differentiated (grade I), moderately differentiated (grade II), and poorly differentiated (grade III). Forty-five cases of DCIS were analyzed for image analysis: nuclear area, DNA ploidy, and vascularization in order to establish a more precise correlation between the histologic grade and these morphometric parameters. Our results confirm that the mean nuclear area, DNA ploidy, and microvessel density (MVD) progressively increased from DCIS grade I to DCIS grade III. The analysis of the nuclear area in relationship to DCIS grading demonstrated a progressive increase of values …
Manual segmentation qualification platform for the EADC-ADNI harmonized protocol for hippocampal segmentation project
2015
The use of hippocampal volumetry as a biomarker for Alzheimer's disease (AD) requires that tracers from different laboratories comply with the same segmentation method. Here we present a platform for training and qualifying new tracers to perform the manual segmentation of the hippocampus on magnetic resonance images (MRI) following the European Alzheimer's Disease Consortium and Alzheimer's Disease Neuroimaging Initiative (EADC-ADNI) Harmonized Protocol (HarP). Our objective was to demonstrate that the training process embedded in the platform leads to increased compliance and qualification with the HarP.Thirteen new tracers' segmentations were compared with benchmark images with respect t…
Metallothionein immunoexpression in non-syndromic and syndromic keratocystic odontogenic tumour
2015
Background To compare the metallothionein (MT) immunoexpression in non-syndromic and syndromic keratocystic odontogenic tumour (KOT), to correlate MT with cellular proliferation, and to evaluate the influence of inflammation in MT. Material and Methods Fourteen cases of KOT were submitted to immunohistochemistry for MT and Ki-67 analysis. The lesions were grouped according to their grade of inflammation, and statistical analysis was performed. Results MT was higher in non-syndromic KOT than in syndromic KOT (p<0.05). No statistical difference in Ki-67 could be identified; however, an inverse correlation was observed between MT and Ki-67 in both lesions. When analysing inflammation, non-synd…
FRI0696 Patient activation and adherence to biological therapy: preliminary results
2018
Background: Medication non-adherence is associated with treatment failure. Some authors show a positive relationship between patient activation and both, adherence to treatment for chronic conditions and improved outcomes. Objectives: To present preliminary results of a study measuring adherence to biological therapy and its relationship with the Patient Activation Measure (PAM) in the outpatient setting. Methods: Ambispective longitudinal observational descriptive study in a general tertiary university hospital. Patients on treatment with the same biological drug for ≥6 months were included in order of arrival. Patients with some degree of mental disability, which prevented understanding o…
Comparison of the effect of pharmacotherapy and neuro-feedback therapy on oral health of children with attention deficit hyperactivity disorder
2018
Background Attention deficit hyperactivity disorder (ADHD) is a chronic and progressive mental disorder related to the childhood period. This study aims to compare the oral health of two groups of ADHD children: those under pharmacotherapy and those under neuro-feedback therapy. Material and methods 72 ADHD children (aged 6-12) were divided into two 36 member groups: The pharmacotherapy group and the neuro-feedback therapy group. Unstimulated salivary flow (USF), DMFT, and plaque index were assessed in these children. Statistical analysis was carried out on the data with the independent t-test, which was performed using SPSS 16. The significance level of the study was p Results In this stud…
Perceived barriers to the provision of preventive care among dentists of Udaipur, India
2015
Aim: To investigate the practice-, patient- and dentist related barriers to the provision of preventive dental care as perceived by dentists of Udaipur city, Rajasthan, India. Settings and Design:- A cross sectional descriptive survey was conducted among 120 dentists of Udaipur city, Rajasthan. Material and Methods: Mean Content Validity Ratio (CVR) was calculated as 0.87 based on the opinions expressed by a panel of total six academicians. Cronbach's coefficient was found to be 0.88, which showed a high internal reliability of the questionnaire. The questionnaire consisted of demographic questions and 12 specific research questions. Statistical analysis used:- Student's t-test and ANOVA te…