A Correlation Technique to Reduce the Number of Predictors to Estimate the Survival Time of HIV/ AIDS Patients on ART

Till now, many research papers have been published which aims to estimate the survivle time of the HIV/AIDS patients taking into consideration all the predictors viz, Age, Sex, CD4, MOT, Smoking, Weight, HB, Coinfection, Time, BMI, Location Status, Marital Status, Drug etc, although all the predictors need not to be included in the model. Since some of the predictors may be correlated/ associated and may have some influence on the outcome variable, therefore, instead of taking both the significantly correlated/ associated predictors, we may take only one of the two. In this way, we may be able to reduce the number of predictors without affecting the estimated survival time. In this paper we have tried to reduce the number of predictors by determining the highly positively correlated predictors and then evaluating the effect of correlation/ association on the survival time of HIV/AIDS patients. These predictors that we have considered in the starting are Age, Sex, State, Smoking, Alcohol, Drugs, Opportunistic Infections (OI), Living Status (LS), Occupation (OC), Marital Status (MS) and Spouse for the data collected from 2004 to 2014 of AIDS patients in an ART center of Delhi, India. We have performed one – way ANOVA to test the association between a quantitative and a categorical variable and Chi-square test to test between two categorical variables. To select one of the two highly correlated/ associated predictors, a suitable model is fitted keeping one predictor independent at a time and other dependent and the model having the smaller AIC is considered and the independent variable in the model is included in the modified model. The fitted models are logistic, linear and multinomial logistic depending on the type of the independent variable to be fitted. Then the true model (having all the predictors) and the modified model (with reduced number of predictors) are compared on the basis of their AICs and the model having minimum AIC is chosen. In this way we could reduce the number of predictors by almost 50% without affecting the estimated survival time with a reduced standard error

Absolute Stability Limit for Relativistic Charged Spheres

We find an exact solution for the stability limit of relativistic charged spheres for the case of constant gravitational mass density and constant charge density. We argue that this provides an absolute stability limit for any relativistic charged sphere in which the gravitational mass density decreases with radius and the charge density increases with radius. We then provide a cruder absolute stability limit that applies to any charged sphere with a spherically symmetric mass and charge distribution. We give numerical results for all cases. In addition, we discuss the example of a neutral sphere surrounded by a thin, charged shell.Comment: 25 pages, 1 figure 1 June 07: Replaced with added citations to prior work along same line

Evaluation of potential rice (Oryza sativa L.) genotypes with different levels of N under rainfed shallow lowland situation

A field experiment was conducted to evaluate the yield of potential rice genotypes during kharif season, 2012 and 2013 at Rice Research Station, Bankura, West Bengal, India on sandy loam soil of slightly acidic in reaction (pH: 5.7). This experiment was conducted in split-plot design with three replications. The results indicated that 105 kg N ha-1, the yield attributes recorded maximum number of panicles m-2 (307.9), panicle length (25.3cm), panicle weight (2.32g), number of filled grains per panicle (117.8), 1000-grains weight (24.5g) and finally recorded highest grain yield (4.80 t ha-1) than lower fertilities. While, 70 kg N ha-1 was remained closed to 105 kg N ha-1 in number of panicles m-2, panicle weight and number of filled grains per panicle. Among the potential rice varieties ‘Sampriti’ (IET 21987) recorded the highest grain yield (4.66 t ha-1) under rainfed shallow lowland situation of red and laterite zone of West Bengal. The highest grain yield (4.80 t ha-1) was obtained at 105 kg N ha-1and it was statistically at par with 70 kg N ha-1 (4.62 t ha-1). Therefore, the increased in grain yield of rice by the varieties due to overall respective performance in growth and appreciable improvement in the yield attributing characters

Structural and magnetization behaviors of Ni substituted Li-Mg ferrites

Magnetization behaviors of Ni-substituted LixMg0.5Ni0.5-2xFe2+xO4 ferrites, where x = 0.25, 0.20, 0.15, 0.10 and 0.00 synthesized by standard ceramic technology sintered at 1300°C in air for 5 hours has been presented in the present study. The bulk density and lattice constants of the samples found to be decreased with the increase in the Ni-content for the x values from 0.25 to 0.00. DC electrical resistivity has found to show highest magnitude at room temperature and decreases with further increase in temperature. Magnetization of the samples has been measured as a function of the field using hysteresis loop tracer at 30°C. It was observed that addition of nickel in polycrystalline Li-Mg ferrites plays an important role in modification of structural and magnetization characteristics

Optimization of Surface Roughness and MRR in EDM Using WPCA

AbstractThe objective of the present study is to find out the optimum combination of process parameters in EDM process so that surface roughness reaches a minimum value and the metal removal rate (MRR) reaches a maximum value. In this study, five roughness parameters (viz. center line average roughness, root mean square roughness, mean line peak spacing, skewness and kurtosis) along with MRR have been considered. To optimize the multi-response problems, Taguchi method alone is unable to solve the problem. Thus, the multi-response characteristics must be converted to a single performance index. In this study weighted principal components analysis (WPCA) method is used for this conversion. For the experimentation, Taguchi L27 orthogonal design with four process parameters, viz., pulse on time, pulse off time, discharge current and voltage at three different levels is used. The optimum combination of process parameters has been found out and verified through the confirmation test. The result of the confirmation test shows a good agreement with the predicted value. This indicates the utility of the WPCA technique as multi-objective optimizer in the field of EDM. In addition, the surface morphology is studied with the help of scanning electron microscopy (SEM) analysis

Linear Stability of Equilibrium Points in the Generalized Photogravitational Chermnykh's Problem

The equilibrium points and their linear stability has been discussed in the generalized photogravitational Chermnykh's problem. The bigger primary is being considered as a source of radiation and small primary as an oblate spheroid. The effect of radiation pressure has been discussed numerically. The collinear points are linearly unstable and triangular points are stable in the sense of Lyapunov stability provided $\mu< \mu_{Routh}=0.0385201$. The effect of gravitational potential from the belt is also examined. The mathematical properties of this system are different from the classical restricted three body problem

Intranuclear Inclusions of Expanded Polyglutamine Protein in Spinocerebellar Ataxia Type 3

AbstractThe mechanism of neurodegeneration in CAG/polyglutamine repeat expansion diseases is unknown but is thought to occur at the protein level. Here, in studies of spinocerebellar ataxia type 3, also known as Machado-Joseph disease (SCA3/MJD), we show that the disease protein ataxin-3 accumulates in ubiquitinated intranuclear inclusions selectively in neurons of affected brain regions. We further provide evidence in vitro for a model of disease in which an expanded polyglutamine-containing fragment recruits full-length protein into insoluble aggregates. Together with recent findings from transgenic models, our results suggest that intranuclear aggregation of the expanded protein is a unifying feature of CAG/polyglutamine diseases and may be initiated or catalyzed by a glutamine-containing fragment of the disease protein

On the Status of Highly Entropic Objects

It has been proposed that the entropy of any object must satisfy fundamental (holographic or Bekenstein) bounds set by the object's size and perhaps its energy. However, most discussions of these bounds have ignored the possibility that objects violating the putative bounds could themselves become important components of Hawking radiation. We show that this possibility cannot a priori be neglected in existing derivations of the bounds. Thus this effect could potentially invalidate these derivations; but it might also lead to observational evidence for the bounds themselves.Comment: 6 pages, RevTex, a few editorial change