Covariance Research Articles

Gauss Process Based Approach for Application on Landslide Displacement Analysis and Prediction

In this paper, the Gauss process is proposed for application on landslide displacement analysis and prediction with dynamic crossing validation. The prediction problem using noisy observations is first introduced. Then the Gauss process method is proposed for modeling non-stationary series of landslide displacements based on its ability to model noisy data. The monitoring displacement series of the New Wolong Temple Landslide is comparatively studied with other methods as an instance to implement the strategy of the Gauss process for predicting landslide displacement. The dynamic crossing validation method is adopted to manage the displacement series so as to give more precise predictions. Different covariance functions are illustrated to give predictive results which show that different covariance functions result in varying levels of prediction accuracy. Comparisons with other methods are also discussed in this study. The results show that the Gauss process can perform better than the RBF network and the SVM methods in this problem in view of the trends according to the original data. Finally, the landslide criterion is given for creep-typed slopes that landslide event would occur imminently if the cross angle at the intersection point of displacement curve changes more than 45 .

Self-Concept of Adolescent Boys and Girls of 11 th and 12 th Standard Of kolkata City: A Comparative Study

Self-concept is a multi-dimensional construct that refers to an individual's perception of 'self in relation to any characteristics. It includes past, present and future selves of an individual. The self-concept may include the perception of one's abilities, motives, attitudes, beliefs, and other personality characteristics. The self-concept is composed of relatively permanent self-assessments, such as the perception of one's personality attributes, skills and abilities, motives, attitudes, beliefs, physical attributes and other personality characteristics. A person's self-concept may change with time, possibly if going through a turbulent periods of identity crisis and reassessments. In other words, the term self-concept refers to the ordered set of attitudes and perceptions that an individual holds about him or herself (Wolffe, 2000; Woolfolk, 2001; Tuttel & Tuttel, 2004).In an interesting study by Blomfield and Barber (2009) the relationship between Australian adolescents' participation in extracurricular activities and their self-concepts was investigated. Adolescents who participated in both sports and non-sports also reported a more positive social self-concept and general self-worth, compared to those who only participated in one of the activity types. This research provides support for extracurricular activities, which is considered as an essential part for learning social behaviour is facilitative of positive self-concept, and demonstrates the importance of a mixed participation profile for an adolescent's self-concept. Ybrandt (2008) observed association between positive self-concept and adjustment and for protection against common problem behaviour. A negative self-concept combined with female gender was risk factor for internalized problems. Self-control had only a direct effect on externalizing behaviour for boys. Adolescents of 15, 16 years of age had a stronger relationship between a negative self-concept and externalizing problem behaviour than younger and older adolescents. Internalizing problem behaviours such as anxiety and depression predicted aggressive and delinquent behaviour. These findings highlight the importance of promoting of a positive self-concept in every adolescent in various psychosocial contexts. Chang et al. (2003) revealed that social self-concept was a stronger correlate of life satisfaction for adolescents than for children.Evidence indicates boys having better self-concept as compared to girls (Park, 2003; Al-Zyoudi, 2007) whereas some studies found exactly the reverse (Wang, 1997). Crain (1996) noted that although the previous research in this area has been somewhat contradictory, there has been a consistent stream of findings documenting significant gender differences in domain specific areas of self-concept. Crain (1996) suggested that these differences were most notable in the areas of physical abilities and physical appearance, where boys appear to have higher levels of self-concept. However, the overall conclusion of this review was that the differences in self-concept among boys and girls are slight. The study by Byrne and Shavelson (1987) tested the invariance of a multidimensional, hierarchical self-concept structure for adolescent males and females. In a covariance structure analysis of data from a sample of 832 (412 males, 420 females) grade 11 and 12 students, with multiple measures of general, academic, English, and mathematics self-concept facets, self-concept structure differed for males and females. Although the number of self-concept factors, pattern of factor loadings (except for one), and hierarchical structure were invariant across gender, relations among the factors differed. Kaur et al., (2009) found self-concept to be positively correlated with academic achievement, though statistically not significant. However, a significantly positive relationship of home environment components of protectiveness, conformity, reward, and nurturance with self-concept has been revealed, and thereby author suggested use of rewards and nurturance from parents for positive self-concept development among adolescents. …

Efficacy of precise sequential therapy for primary liver cancer

Objective To investigate the construction and implementation of the concept of precise sequential therapy for primary liver cancer.Methods The clinical data of 207 patients with resectable liver cancer who were admitted to the Air Force General Hospital from May 2005 to June 2010 were retrospectively analyzed.Of all the patients,81 received conventional therapy (conventional therapy group),and the other 126 patients received precise sequential therapy (precise sequential therapy group).The conditions of the patients in perioperative phase,during postoperative sequential treatment and the period of follow-up between the 2 groups were compared.All data were analyzed by using the covariance analysis,analysis of variance,chi-square test or rank sum test.Results The detection rates of lesions with a diameter less than 1 cm,operation time,liver resection volume,intraoperative blood loss,rate of perioperative blood transfusion,duration of postoperative hospital stay,incidences of postoperative complications were 81％ (22/27),( 186 ± 36) minutes,(75 ± 29) ml,( 189 ± 60) ml,24％(30/126),(21 ± 12)days and 13％ (17/126) in the precise sequential therapy group,and 18％ (2/11),(222 ± 30)minutes,(133 ±88)ml,(327 ±46)ml,51％ (41/81),(26 ± 17)days and 20％ (16/81) in the conventional therapy group,respectively,with significant differences between the 2 groups (F =10.876,7.390,46.996,31.025,14.556,6.315,4.017,P ＜ 0.05).No significant difference was observed on the levels of alanine transaminase,albumin and the Child-Pugh score before and after the intervention in the precise sequential therapy group,but significant differences were observed in the conventional therapy group.The 1-,2-,3-year tumor recurrence rates and the 1-,2-,3-year survival rates were 17％ (21/126),22％ (17/76),26％ (8/31) and 87％ (110/126),87％ (66/76),84％ (26/31) in the precise sequential therapy group,and 31％ (25/81),38％ (27/71),48％(31/65 ) and 77％ (62/81),75％ (53/71 ) and 60％ (39/65) in the conventional therapy group,respectively.There were significant differences in the prognosis of the patients in the 2 groups ( x2 =4.958,4.292,4.168,4.062,3.640,5.470,P ＜ 0.05 ).Conclusion Through accurate assessment of the patients' condition before surgery,precise hepatectomy and precise postoperative intervention,the goal of effective control of tumor recurrence,maximum protection of the liver function and improvement of the survival rate can be achieved. Key words: Liver neoplasms; Precise sequential therapy; Liver function assessment; Hepatectomy ; Intervention

Distribution of the soil moister in Chinteni area using principal component analysis.

In this note was studied the soil moisture distribution at different depth and sites using theprincipal component analysis and SixPack free software. This method provides information used toemphasize the principal component of the soil moisture that allows characterizing all other soil moistersamples at different depth and sites using principal component obtained following the singular valuedecomposition of the covariance matrix for the matrix that organize the initial sets of measurements.

The Effects of Perceived Quality toward User Performance and Corporate Performance in Production Information Systems

The purpose of this study is to investigate the perceived quality toward user performance and corporate performance in production information systems. For this purpose, a research model and hypotheses are developed based on the relevant literature reviews. Data have been collected from 132 enterprises which have implemented production information systems, and the research hypotheses were tested by covariance structural model analysis. The results of this empirical study are summarized as follows. First, production information quality and support service quality are confirmed to have a positive effect on user's satisfaction, however, I found no evidence of a statistically significant relationship between system quality and user's satisfaction. Second, all of three quality factors which are production information quality, system quality, and support service quality have positive influence on system usage. Third, user's satisfaction has positive influence on system usage, and both of user's satisfaction and system usage have positive influence on performance improvement. Based on these findings, this study suggested the implications, as well as limitations and further research directions.

Characteristics, Covariances and the Value Effect of S&P 500 Index Addition

Characteristics, Covariances and the Value Effect of S&P 500 Index Addition

Genotype by Country Interaction for Birth and Weaning Weights for Shorthorn Cattle in Australia and the United States

Birth (BW) and weaning weights (WW) of Shorthorn beef cattle used to study the genotype by country (G´C) interactions between Australia (AU) and the United States (US). Data were collected depending on the connectedness on genetic links of common sires. The edited data consisted of numbers of sire, dam and calf of 2,013, 19,784 and 42,963 in AU and 4,797, 38,648 and 95,849 in the US, respectively. After that, sets of data were combined together and corresponding traits from different countries were treated as different traits. Therefore, a bivariate animal model including maternal genetic and permanent environment effects was used to study the interactions. No covariance due to maternal permanent environmental and environmental effects {cov(pe1,pe2) and cov(e1,e2) = 0} was assumed. Estimates of (co)variance components have been done by restricted maximum likelihood. Variance component estimates of the same trait across countries were slightly different. Direct and maternal genetic correlations (in parentheses) between corresponding traits were 0.93 (0.93) and 0.78 (0.86) for BW and WW, respectively. This implied that a joint BW genetic evaluation could be conducted using a model that treated the information as a single population. For WW, sires across AU and the US needed evaluation to consider carefully the G´C interactions.

The Effectiveness of Positive Parenting Skills Training Group for Parents of Children with Attention Deficit Disorder- Hyperactivity on Behavior Disorders in their Children

Recent years have witnessed increasing problems of parents of children affected with disorder in different fields. The aim of this article is to determine the effectiveness of group training of positive parenting of children affected with attention deficit hyperactivity disorder (ADHD). The current research is of quasi-experimental and of pre and post test type of study. In this study, 46 children with attention deficit hyperactivity disorder which referred to occupational therapy centers in Tehran, were randomly selected as the two groups of experiment and control. In addition to drug therapy and occupational therapy programs, mothers of those children received eight (2h) sessions of group training of positive parenting program and the control group did not receive the training. A post-test are performed on both of the groups after the completion. Demographic information and 48-questions (questionnaire of Conners classification scale of parents) are used and the data used by ANCOVA are applied. To review the test assumptions, covariance analysis test is used and the data are analyzed by SPSS software. The average scores of behavioral disorders decreased in post-test of related experimental group, which indicates that group training program of Sanders parenting impact, is positive. (F=5247, sig< 0.005). Hence, this model is recommended to be used as one of the training patterns to the parents to reduce behavioral disorders of ADHD children.

A Collaborative Classifier for Local and Global Learning

Inspired by covariance matrix stating data direction globally,we construct a novel large margin classifier called collaborative classification machine with local and global information(C2M).By the median rule of combining classifiers,this model collaboratively learns the decision boundary from two hyperplanes with global information.The proposed C2M algorithm can be individually solved as a quadratic programming(QP) problem,and has O(2N3) time complexity that is faster than O(N4) of existing maxi-min margin machine(M4).We describe the C2M model definition,provide the geometrical interpretation,and present theoretical justifications.As a major contribution,we show that C2M can robustly utilize the global information when M4 loses the global information on those data sets with confused classes margin.We also exploit kernelization trick and extend C2M to nonlinear classification.Moreover,we show that C2M can be transformed into standard support vector machine(SVM) model and can be solved by other quick algorithms widely used by SVM.Furthermore,we propose four indicators to evaluate the global impact of covariance matrix on classification.Experiments on toy and real-world data sets demonstrate that the C2M has comparable performance with SVM that utilizes only local information,while the C2M is more robust and time saving than M4.

Database for Time-of-flight Spectra Including Covariances

Database for Time-of-flight Spectra Including Covariances

Identifying population‐ and community‐level mechanisms of diversity–stability relationships in experimental grasslands

Summary1. While positive effects of biodiversity on temporal stability of communities have been demonstrated in theoretical and empirical studies, diversity–stability relationships at the population level remain poorly understood.2. We investigated temporal variability of plant populations in experimental grassland plots of varying species richness (1, 2, 4, 8, 16–60 species), functional group richness and composition (presence/absence of legumes × grasses × small herbs × tall herbs) in a long‐term biodiversity experiment from 2003 to 2009 (‘Jena Experiment’).3. Average population stability, defined as the reciprocal of the coefficient of variation of above‐ground biomass production over time, differed largely between species but was generally higher in grasses and small herbs than in legumes and tall herbs. Furthermore, population stability was positively related to a species’ proportional contribution to community biomass. Thus, an increasing number of subordinate species explained lower average population stabilities at higher diversity levels.4. A negative covariance (CV) across all species‐richness levels suggested negatively correlated species dynamics. Species belonging to different functional groups fluctuated asynchronously, while species dynamics within functional groups were more synchronous. Community‐wide species synchrony decreased with increasing species richness, and temporal stability at the community level increased.5. Synthesis: Our results suggest that diversity–stability relationships are driven by fluctuations in the population biomass of individual species which are less synchronized in more diverse than in less diverse mixtures and monocultures. Dominant plant species tend to be more stabilized than subdominant species, independently of community species richness. However, asynchrony of population dynamics outweighs decreasing population stability with increasing species richness, resulting in higher temporal stability at the plant community level.

Change of plasma resistin concentration in patients with traumatic brain injury

Objective To determine plasma resistin level in patients with traumatic brain injury (TBI) and evaluate its correlations with outcome and inflammatory reaction. Methods Fiftyfour patients with moderate TBI, 71 patients with severe TBI and 40 healthy controls were enrolled in this study. Plasma samples were obtained from the healthy controls on physical examination and from the TBI patients on admission. Enzyme-linked immunosorbent assay ( ELISA) was used to determine the plasma resistin concentrations. Results Twenty patients (37.0% ) and 53 patients (74.6% ) with moderate and severe TBI suffered from an unfavorable outcome (defined as GOS score for 1-3 points) three months after TBI respectively. Plasma resistin levels in the patients with moderate and severe TBI were substantially higher than that in the healthy controls ((21. 9 ± 8. 4) ng/ml and (29. 2 ± 9. 6) ng/ml vs (9. 3 ± 2.6) ng/ml, both P ＜0. 01] by using covariance analysis. By using the multivariate linear regression analysis, plasma C-reactive protein level (t =2.212,P =0.035; t =2. 274,P =0. 014) and GCS scores (t =3. 120,P =0.007; t=3.986,P=0.003) were associated with the plasma resistin levels. Logistic regression analysis selected plasma resistin level as an independent predictor for 3-month unfavorable outcome of the patients with moderate and severe TBI (odds ratio = 1. 124, 95% CI = 1. 040-1. 221, P = 0.011; odds ratio = 1. 145, 95% CI = 1. 044-1. 232, P = 0. 009). A receiver operating characteristic curve identified cutoff levels of plasma resistin (22.4 ng/ml and 30.5 ng/ml) that predicted 3-month unfavorable outcome of moderate and severe TBI patients with the high sensitivity (70. 0% and 79. 2% ) and specificity (70.6% and 72.2% ) ( area under curve = 0.719, 95% CI = 0.642-0.829, P = 0.000;area under curve =0.735, 95% CI =0. 671-0. 893, P = 0.000). Conclusions Plasma resistin level is increased after TBI and may be involved in inflammatory response of brain injury. Clinical detection of this indicator can help early determine the prognosis of the TBI patients. Key words: Brain injuries; Resistin; Inflammation; Prognosis

The in vitro and in vivo experimental study of long-circulating superparamagnetic iron oxide liposome nanoparticles as novel MR contrast agent

Objective To evaluate pharmacodynamics of prepared long-circulating superparamagnetic iron oxide (SPIO) liposomes. Methods Control and experimental groups were established after adding SPIO or long-circulating SPIO liposomes as agents. (1)Macrophages experiment in vitro: the RAW 264.7 macrophage cell strains were recovered, cultured and seeded in the culture plate at a density of 2.5×105 cells/well until they reached 80%-90% confluence. The intracellular Fe uptake of control and experimental group cells were quantified by Ferrozine assay after incubation with different concentrations of drugs. Factorial design analysis of variance was used as statistics method. Prussian blue staining method was used to detect staining of experimental cells.(2)Drug biodistribution in mice: C57BL/6J(n=6) were classified into blank control group (n=2), control group(n=2) and experimental group(n=2).Saline, SPIO and long circulating SPIO were injected via the tail vein in the blank control group, control group and experimental group respectively. Then distribution of drugs in the body was observed by pathological examination.(3) MR imaging of tumor-bearing nude mice: 20 BALB/c nude mice bearing lung cancer models were established and classified into control group and experimental group. After administration of drugs, all animals underwent MR scanning. Signal intensities of livers and tumors were measured, SNR-time dynamic curves were drew. Covariance analysis was used to compare post-enhanced SNR at the 12th hour. (4)Cytotoxicity studies (MTT): cytotoxicity of both drugs on human liver cell line HL-7702 was studied, and statistically analyzed using factorial design analysis of variance. Results (1) Macrophages experiment in vitro: The nanoparticle uptake by macrophage cells evaluated by ferrozine assay showed the uptake of blank SPIO was higher than long-circulating SPIO liposomes. Compared with the blank control group, there was strong blue staining in the macrophages with Prussian staining in the control group and little blue staining in the experimental group. (2) Drug biodistribution in mice: for blue stained cells composed of iron particles, the amounts in the liver, spleen, lung, kidney of the control group were more than those in the experimental group. (3) MR imaging of tumor-bearing nude mice: the non-enhanced SNR of livers and tumors in the control group and experimental group were 31.47 ± 0.56, 30.89 ± 1.41, 58.41 ± 0.61, 58.44 ± 1.08, respectively. After injecting of contrast agents, SNR of livers and tumors in the control group and experimental group were 17.00 ± 0.96, 22.29 ± 0.73, 58.50 ± 0.63, 52.47 ± 1.18, respectively. The covariance analysis showed that SNR of the livers in the control group after 12 hours was significantly lower than the experimental group (F=167.022, P=0.000); while the SNR of the tumors in the experimental group was significantly lower than the control group (F=266.106, P=0.000).(4) Cytotoxicity of nanoparticles by MTT method: the viability of HL-7702 cells tend to decrease with the increase of Fe concentration. Cytotoxicity in the long-circulating SPIO liposomes was lower than the SPIO(F=2256.204,P=0.000). Conclusions Long-circulating SPIO liposomes we prepared reveal suitable sizes, even distribution, and good anti-macrophage ability in vitro and in vivo. They have long circulation characteristic and T2 negative enhancement effect in the transplanted lung cancers, while they still maintain low cytotoxicity. Key words: Contrast media; Nanotechnology; Magnetic resonance imaging; Animals,laboratory

Lombalgia durante a gestação: eficácia do tratamento com Reeducação Postural Global (RPG)

Realizou-se um estudo clínico comparativo com o objetivo de avaliar o efeito da Reeducação Postural Global (RPG) no tratamento da lombalgia durante a gravidez e sua relação com limitações funcionais das gestantes. Os sujeitos foram 34 gestantes nulíparas atendidas em três centros de saúde e um hospital privado de Campinas, com idade gestacional entre 20 e 25 semanas e queixa de dor lombar. Dezessete gestantes foram submetidas a sessões de RPG durante oito semanas consecutivas, e as demais seguiram orientações de rotina para controle da dor lombar. Em cada sessão de RPG avaliou-se a intensidade da dor percebida pela mulher, antes e após os procedimentos. O grupo controle foi avaliado quanto à intensidade da dor na admissão, às quatro e oito semanas do estudo. Aplicou-se o questionário Roland-Morris para avaliar limitações funcionais, ao início e final do acompanhamento. O grupo de RPG apresentou decréscimo estatisticamente significativo na intensidade da dor antes e depois das sessões. Ao longo do estudo, as mulheres submetidas a RPG tiveram medianas de intensidade da dor e médias do escore de limitações funcionais significativamente menores que as do grupo controle. Análise de covariância indicou que o tratamento com RPG estava associado à menor intensidade da dor percebida ao final do estudo. Conclui-se que a RPG pode dar importante contribuição no tratamento da dor lombar durante a gestação, reduzindo, ao mesmo tempo, as limitações funcionais.

Investigation on performance of evapotranspiration temporal upscaling methods based on eddy covariance measurements

Investigation on performance of evapotranspiration temporal upscaling methods based on eddy covariance measurements

PILATES EXERCISE EFFECT ON PAIN AND GENERAL HEALTH OF FEMALE PATIENTS WITH CHRONIC LOW BACK PAIN

Background : There is ample evidence supporting the effectiveness of exercise in management of chronic low back pain. Recently, there has been a growing interest in Pilates exercise among researchers and other professionals involved in this subject. The purpose of this study was to evaluate the effects of Pilates exercise on chronic low back pain. Material and Methods: twenty-eight patients with chronic low back pain were randomly assigned to Pilates (n=15, mean age 40.20±8.07 yrs) and control group (n=13, mean age 38.30±7.84 yrs). The Pilates group underwent a six-week Pilates training program and the control group received routine treatments. Level of pain and General health status were respectively measured through Visual Analog Scale (VAS) and General Health Questionnaire (GHQ28) before and after the intervention. Covariance test with the variety factor (pre-test) in the level of α =0.05 was applied for statistical analysis of data. Results: after 6 weeks of treatment, the mean score of pain (p=0.024), and general health (p=0.04), as observed in Pilates group, was less than the usual-treatment group. Conclusion: The findings from the present study indicate that the selected Pilates exercises was more effective than the usual treatment methods in reducing pain level and improving general health in the patients with chronic low back pain. Therefore prescribing Pilates exercise for patients with chronic low back pain is suggested. Keywords: Pilates exercises, Chronic Low Back Pain, usual treatment, general health

Effects of pregnancy complicated with diabetes on insulin sensitivity of offspring during their early childhood

Objective To investigate the effects of pregnancy complicated with diabetes on the insulin sensitivity of offspring during their early childhood. Methods Offspring of diabetic mothers(ODM) and of non-diabetic mothers(ONDM) aged 1 month to 24 months were recruited into this prospective cohort study and followed up for two years. Body weight and body length were measured at 2, 4, 6, 8, 10, 12, 18 and 24 months of age respectively, and body mass index (BMI) were calculated. Fasting plasma glucose and fasting serum insulin levels were measured on the following-up day at 6, 12 and 24 months of age and insulin sensitivity index (ISI) was calculated. Homeostasis model assessment was used to calculate the insulin resistance (HOMA-IR). Insulin sensitivity was evaluated by fasting serum insulin, ISI and HOMA-IR. The difference of insulin sensitivity between ODM and ONDM group were examined by analysis of covariance adjusted by gender, gestational age,birth weight and BMI. Results Six hundred and five babies including ninety ODM and five hundred and eleven ONDM met the inclusion criteria. There were no differences in gender, gestational age,birth-weight/height between the two groups(P＞0. 05). ODM were heavier and higher than ONDM at each measure point during early childhood, but there were statistical differences at the age of 2, 4 and 6 months only (P＜0. 05). And the BMI at age of 2 and 4 months of ODM were higher than those of ONDM(P＜0.05). The number of baby who accepted the measurement of fasting plasma glucose and fasting serum insulin levels at 6, 12 and 24 months of age was 276 cases, 273 cases and 56 cases respectively. The fasting serum insulin of ODM (logarithmically transformed) were 0. 95±0. 30,0. 89±0. 34 and 0. 90±0. 27, which were higher than those of ONDM (0. 70±0. 45, 0. 73±0. 35 and 0. 67±0. 30) (t=9. 58, 5.01 and 6. 11, P＜0.05); HOMA-IR (logarithmically transformed) were 0. 34±0. 33, 0. 27±0. 36 and 0. 27±0. 31, which were higher than those of ONDM also(0.08±0. 46,0. 10±0. 36 and 0. 03 ± 0.33) (t= 9. 55, 4. 79 and 5. 06, P＜0.05); ISI(natural logarithmically transformed) were -3.87±0. 75, -3.73±0. 81 and -3. 73±0. 71, which were lower than those of ONDM(-3.29±1.05, -3.35±0.84 and -3.18±0. 77) (t=9.20, 4. 90 and 5.06, P＜0.05).There were differences in feeding characteristics of ODM between insulin sensitive subgroup [40. 9%(9/22) breast-feeding] and insulin insensitive subgroup [16.67 % (12/72) breast-feeding] (x2 = 7.02,P=0. 03). Conclusions Pregnancy complicated with diabetes has adverse effects on the offspring insulin sensitivity during their early childhood, and affects the early growth and development of them.Breast-feeding might decrease insulin resistance in babies. Key words: Diabetes,gestational; Infant; Insulin resistance; Breast feeding

A novel robust two-stage extended Kalman filter for bearings-only maneuvering target tracking

A novel robust filter is proposed via embedding extended Kalman filter into an optimal two-stage Kalman filter, which is improved through a modified Sage-Husa noise statistics estimator. Meanwhile, strong tracking multiple fading factors are introduced in this paper to improve the tracking performance for high maneuvering targets. The new method provides an optimal estimation of the target state through a combination of the output of the first stage (a “bias-free” filter) and that of the second stage (a “bias-compensating” filter). Furthermore, the unknown statistical parameters of virtual noises are estimated online, and the predicted covariance can be adjusted in real time by fading factors when high maneuvers occur. Simulation results of tracking a maneuvering target by 3 passive sensors show that the proposed algorithm has advantages over the conventional method in terms of the numerical accuracy with only a little additional computational cost. Key words: Target tracking, two-stage Kalman filter, noise statistics estimator, multiple fading factors.

Plasma levels of N-terminal pro-B-type natriuretic peptide in patients with metabolic syndrome

A retrospective analysis was made on clinical data of 230 cases of metabolic syndrome (MS) and 239 cases of non-MS admitted to department of cardiology and endocrinology of Huashan Hospital from July 2005 to August 2009.Multiple linear regression analysis was performed to assess the association between levels of N-terminal pro-B-type natriuretic peptide (NT-proBNP) and potential influencing factors.Covariance analysis was used for group comparison.Multiple linear regression analysis demonstrated that age,body mass index,systolic blood pressure,diastolic blood pressure,insulin resistance index,triglyceride,low density lipoprotein-cholesterol,creatine,left atrial diameter,left ventricular posterior wall dimensions,left ventricular ejection fraction were independent predictors for plasma levels of NT-proBNP in those subjects(P ＜ 0.05).Covariance analysis showed that plasma levels of NT-proBNP in MS group were significantly lower than those in non-MS group ( P ＜ 0.05).Further analysis found that plasma levels of NT-proBNP in MS patients with high triglyceride and body mass index,but normal systolic and diastolic blood pressure,normal fasting plasma glucose were significantly lower than those in non-MS group ( P ＜ 0.05 ).The results indicate that decreased plasma levels of NT-proBNP might be related to lipids disorder and obesity of MS patients. Key words: Metabolic syndrome X; N-Terminal Pro-B-Type Natriuretic peptide

Identification of clusters in tissue samples in gene expression data with Principal Component Analysis based on relative variance matrix

Principal Component Analysis (PCA) has been in use as a preprocessing step to clustering for long. We have focused on the clustering of tissue samples in gene expression data. Different clustering techniques and algorithm are available in literature on gene expression data but with the existing ambiguity on the number of clusters, apart from relying on biologically known groups. A consensus is needed to reach on the number of clusters in the wide variety of existing clustering techniques based on different similarity or dissimilarity metrics. The conventional usage of PCA for clustering is either by forcing the unit variance to each variable or the high magnitude of variance of an individual variable is allowed to dominate the entire results of PCA. We propose the use of relative variance covariance method in PCA, so as to give due consideration to the joint and individual variances in the dataset and identify clusters with principal component loadings. We emphasize empirically that the proposed approach of PCA is conclusively more informative than the available approaches to identify cluster structure in tissue samples (sample expression profiles). Clusters formed are valid with the existing results on the data set under study and with valid biological background. Key words: Clustering methods, gene expression analysis, principal component analysis, the relative variance covariance matrix, principal component loadings.