A semi-Markov model for stroke with piecewise-constant hazards in the presence of left, right and interval censoring.

This paper presents a parametric method of fitting semi-Markov models with piecewise-constant hazards in the presence of left, right and interval censoring. We investigate transition intensities in a three-state illness-death model with no recovery. We relax the Markov assumption by adjusting the intensity for the transition from state 2 (illness) to state 3 (death) for the time spent in state 2 through a time-varying covariate. This involves the exact time of the transition from state 1 (healthy) to state 2. When the data are subject to left or interval censoring, this time is unknown. In the estimation of the likelihood, we take into account interval censoring by integrating out all possible times for the transition from state 1 to state 2. For left censoring, we use an Expectation-Maximisation inspired algorithm. A simulation study reflects the performance of the method. The proposed combination of statistical procedures provides great flexibility. We illustrate the method in an application by using data on stroke onset for the older population from the UK Medical Research Council Cognitive Function and Ageing Study

Numerical Computation of p-values with myFitter

Likelihood ratio tests are a widely used method in global analyses in particle physics. The computation of the statistical significance (p-value) of these tests is usually done with a simple formula that relies on Wilks' theorem. There are, however, many realistic situations where Wilks' theorem does not apply. In particular, no simple formula exists for the comparison of models that are not nested, in the sense that one model can be obtained from the other by fixing some of its parameters. In this paper I present methods for efficient numerical computations of p-values, which work for both nested and non-nested models and do not rely on additional approximations. These methods have been implemented in a publicly available C++ framework for maximum likelihood fits called myFitter and have recently been applied in a global analysis of the Standard Model with a fourth generation of fermions

A PROSPECTIVE STUDY OF SERUM FOLATE CONCENTRATION AND HEMOGLOBIN IN CERVIX CARCINOMA PATIENTS

Objective: The study aimed to have a prospective study of serum folate concentration and hemoglobin (Hb%) in cervical carcinoma patients. Methods: The study was conducted on women suffering from carcinoma cervix. The research was conducted in the Gynecological Outpatient Department (OPD) of the Oncology Unit in Mahavir Cancer Sansthan Patna, Bihar. The study period was from May 2016 to April 2017. The sample was collected after face to face interview by Figo staging and the sample was taken regularly. As a result strong association of Hb% and carcinoma cervix was found with the mean value of lower than 11.12, which is lower than the normal range of Hb%. As per the further estimation of folic acid, the level of cervical cancer is low. Results: The data were estimated with help of tools such as SPSS 16.0 and PRISMA 5.0. The Hb% the mean value of patients was estimated to be lower than 11.12, which is not under the normal range of Hb%, that is, nearly 12.5 mg/dl. The low mean value shows less Hb% content which leads to anemia in normal beings as well as in patients with cervical cancer. A strong association of Hb% which affected to patients in carcinoma cervix can be seen in the graph that the mean value of patients low 11.12±0.20 which not comes under normal range of Hb%, that is, 12.5 mg/dl. The R square value is 0.9556. Conclusion: As per our study, we have estimated that the folic acid level in cervical cancer is low. The -normal range of folic acid level in plasma serum is 2.2–20 ug/ml. The mean of 20 control cases, new cervical cancer patients, on treating patients, and follow-up patients is 11.08, 2.206, 3.554, and 2.783, respectively. The control 11.08 shows the better level in plasma serum level comes under a normal range of folic acid level

Enhancing structure relaxations for first-principles codes: an approximate Hessian approach

We present a method for improving the speed of geometry relaxation by using a harmonic approximation for the interaction potential between nearest neighbor atoms to construct an initial Hessian estimate. The model is quite robust, and yields approximately a 30% or better reduction in the number of calculations compared to an optimized diagonal initialization. Convergence with this initializer approaches the speed of a converged BFGS Hessian, therefore it is close to the best that can be achieved. Hessian preconditioning is discussed, and it is found that a compromise between an average condition number and a narrow distribution in eigenvalues produces the best optimization.Comment: 9 pages, 3 figures, added references, expanded optimization sectio

Southwestern Ontario secondary adult day-school teachers\u27 perceptions of the effects of changes in education on their work lives and on their dispositions toward future educational change.

The educational literature of the past 35 years was dominated by studies examining innovations, school improvements, and educational restructuring. Few of these efforts to change schools were considered successful. Researchers have more recently focused on systemic reform and the pivotal role teachers play in ensuring its success. The purpose of this study was to determine how a sample of southwestern Ontario secondary adult day-school teachers perceived change, how the educational changes altered their work lives, and how these alterations affected their dispositions toward future educational change. This was accomplished through a questionnaire completed by 41 teachers from 5 secondary adult day-schools in June, 1995 to January, 1996. In order to recognize the context of these teachers\u27 contributions, a follow-up researcher-completed interview was also conducted with 21 teachers and 5 school leaders. Findings indicated that participants were positive about the changes in the past 5 years which they considered to have had the strongest effect on their work lives. Those changes tended to be changes in policy or practice regarding both subject matter and teaching methodologies or school structure and were initiated or planned by the teachers. Despite the resource and time constraints resulting from the changes, participants believed such changes made it easier for them to meet students\u27 needs, improved their relationships with students, were beneficial for students, made teaching more satisfying, and enhanced teacher collaboration and professionalism. Teachers, however, perceived that they were generally unprepared for and not in control of change. Even with these concerns, most teachers and school leaders were very willing to be active participants in similar future changes or future change in general. Paper copy at Leddy Library: Theses & Major Papers - Basement, West Bldg. / Call Number: Thesis1996 .S56. Source: Masters Abstracts International, Volume: 37-01, page: 0023. Adviser: Colin Ball. Thesis (M.Ed.)--University of Windsor (Canada), 1996

Global convergence of a primal-dual interior-point method for nonlinear programming

Many recent convergence results obtained for primal-dual interior-point methods for nonlinear programming, use assumptions of the boundedness of generated iterates. In this paper we replace such assumptions by new assumptions on the NLP problem, develop a modification of a primal-dual interior-point method implemented in software package LOQO and analyze convergence of the new method from any initial guess

Grey-box model identification via evolutionary computing

This paper presents an evolutionary grey-box model identification methodology that makes the best use of a priori knowledge on a clear-box model with a global structural representation of the physical system under study, whilst incorporating accurate blackbox models for immeasurable and local nonlinearities of a practical system. The evolutionary technique is applied to building dominant structural identification with local parametric tuning without the need of a differentiable performance index in the presence of noisy data. It is shown that the evolutionary technique provides an excellent fitting performance and is capable of accommodating multiple objectives such as to examine the relationships between model complexity and fitting accuracy during the model building process. Validation results show that the proposed method offers robust, uncluttered and accurate models for two practical systems. It is expected that this type of grey-box models will accommodate many practical engineering systems for a better modelling accuracy

The detection of globular clusters in galaxies as a data mining problem

We present an application of self-adaptive supervised learning classifiers derived from the Machine Learning paradigm, to the identification of candidate Globular Clusters in deep, wide-field, single band HST images. Several methods provided by the DAME (Data Mining & Exploration) web application, were tested and compared on the NGC1399 HST data described in Paolillo 2011. The best results were obtained using a Multi Layer Perceptron with Quasi Newton learning rule which achieved a classification accuracy of 98.3%, with a completeness of 97.8% and 1.6% of contamination. An extensive set of experiments revealed that the use of accurate structural parameters (effective radius, central surface brightness) does improve the final result, but only by 5%. It is also shown that the method is capable to retrieve also extreme sources (for instance, very extended objects) which are missed by more traditional approaches.Comment: Accepted 2011 December 12; Received 2011 November 28; in original form 2011 October 1

HARES: an efficient method for first-principles electronic structure calculations of complex systems

We discuss our new implementation of the Real-space Electronic Structure method for studying the atomic and electronic structure of infinite periodic as well as finite systems, based on density functional theory. This improved version which we call HARES (for High-performance-fortran Adaptive grid Real-space Electronic Structure) aims at making the method widely applicable and efficient, using high performance Fortran on parallel architectures. The scaling of various parts of a HARES calculation is analyzed and compared to that of plane-wave based methods. The new developments that lead to enhanced performance, and their parallel implementation, are presented in detail. We illustrate the application of HARES to the study of elemental crystalline solids, molecules and complex crystalline materials, such as blue bronze and zeolites.Comment: 17 two-column pages, including 9 figures, 5 tables. To appear in Computer Physics Communications. Several minor revisions based on feedbac