Multivariate Statistical Studies Research Articles

Evaluation of Groundwater Chemistry and Multivariate Statistical Studies in Parts of Tirupur District, India

Groundwater quality at any location depends on the mutual possessions of several progressions beside the subsurface flow path. The natural history and degree of infectivity in a particular region can be ascertained by hydro-chemical statistics. In order to assess the groundwater chemistry and its appropriateness for consumption purposes, sixty-three subsurface water samples were analyzed. Based on the perceptive of the hydro-geological and groundwater environment, the chemical characteristics of the groundwater were evaluated. The favored parameters for the quality assessment were major anions and cations along with pH, turbidity, total dissolved solids, total hardness, fluoride and iron as trace metals. Total dissolved solids distribution, hydro-chemical facies, Piper diagram, factor analysis, correlation studies and cluster analysis were done to monitor the study zone. The total dissolved solids (TDS) were clustered independently. It was concluded from the assessment that the groundwater of the Tirupur region was critically deteriorated by different anthropogenic activities.

Intake of toxic metals through dietary eggs consumption and its potential health risk assessment on the peoples of the capital city Dhaka, Bangladesh

Around the world, hen meat and eggs are very widely consumed in dishes like curries, processed cuisine, and fast food. The ingestion of contaminated eggs poses a biochemical risk from the perspective of food safety due to the presence of heavy metal and trace element residues in hen eggs. The purpose of this study was to examine the concentrations of heavy metals in eggs from commercial chicken farms from capital city and hens from local area in order to identify the most significant heavy metal concentration in hen eggs. The concentrations of Cd, Cr, Cu, Pb, Mn, Ni, Fe, Zn, Co and As in samples of hen eggs collected from different locations were measured in the present study and concentrations of these selective metals were found to be between < 0.001, 0.01–0.89, 0.81–0.015, 0.81–58.8, 0.32–1.9, 0.05–1.03, 0.04–0.38, 10.6–104.02, 2.41–48.46, 0.04–0.5 mg/kg-fw and BDL respectively. The findings showed that Cu, Pb, Fe and Zn had levels over the dietary food's maximum permissible limit (MPL). Multivariate statistical studies showed that human activity was the main contributor to the presence of heavy metals in the sampled diets. Estimated daily intake (EDI), target hazard quotient (THQ) of individual heavy metals, and carcinogenic risk (CR) for lifetime exposure were used to evaluate the risks to human health associated with dietary intake of these metals through consumption of hen eggs. Provisional tolerable daily intake values (PTDI) for Pb, Cu, Zn, and Fe were higher, indicating that these metals might be harmful to human health if consumed in eggs by both children and adults. The evaluated foodstuffs can be consumed with low or less risk of exposure to heavy metals because the computed values of THQ and CR were below their respective allowed thresholds.

Hydrogeochemical Studies to Assess the Suitability of Groundwater for Drinking and Irrigation Purposes: The Upper East Region of Ghana Case Study

Groundwater is increasingly being used to help meet the Sustainable Development Goals (SDGs) 2 and 6 in many parts of the world, including Ghana. Against this background, hydrogeochemical and multivariate statistical studies were conducted to determine the physicochemical characteristics and suitability of groundwater in some agrarian communities in the Upper East Region of Ghana for drinking and irrigational farming. Additional analyses were also performed to identify potential health risks associated with the groundwater use and to better understand the hydrogeochemical processes controlling groundwater evolution for its effective management. The results showed that the groundwater is typically fresh; moderate to very hard in character; undersaturated with calcite, dolomite, halite, and gypsum; and supersaturated with quartz and amorphous silica. The physicochemical characteristics of the groundwater are controlled by both anthropogenic and natural activities/processes, such as fertilizer application, irrigation return flows, rock weathering, and forward/reverse cation exchange. The total dissolved solids (TDS) (165–524 mg/L), electrical conductivity (EC) (275–873 μS/cm), sodium percentage (Na%; 9.05–17.74%), magnesium ratios (MR) (29.25–53.3%), permeability index (PI) (36.6–74.6%), and sodium adsorption ratio (SAR) (0.20–0.51) point to the possibility of using the groundwater for irrigation, however, with some salinity control. The water quality and health risk analysis also revealed that the groundwater can be used for drinking; however, the high concentrations of fluoride, which can cause noncarcinogenic health issues such as dental and skeletal fluorosis in both adults and children, must be reduced to the WHO required level of 1.5 mg/L.

Diabetes mellitus type 2: Exploratory data analysis based on clinical reading

AbstractDiabetes mellitus type 2 (DMT2) is a severe and complex health problem. It is the most common type of diabetes. DMT2 is a chronic metabolic disorder that affects the way your body metabolizes sugar. With DMT2, your body either resists the effects of insulin or does not produce sufficient insulin to continue normal glucose levels. DMT2 is a disease that requires a multifactorial approach of controlling that includes lifestyle change and pharmacotherapy. Less than ideal management increases the risk of developing complications and comorbidities such as cardiovascular disease and numerous social and economic penalties. That is why the studies dedicated to the pathophysiological mechanisms and the treatment of DMT2 are extremely numerous and diverse. In this study, exploratory data analysis approaches are applied for the treatment of clinical and anthropometric readings of patients with DMT2. Since multivariate statistics is a well-known method for classification, modeling and interpretation of large collections of data, the major aim of the present study was to reveal latent relations between the objects of the investigation (group of patients and control group) and the variables describing the objects (clinical and anthropometric parameters). In the proposed method by the application of hierarchical cluster analysis and principal component analysis it is possible to identify reduced number of parameters which appear to be the most significant discriminant parameters to distinguish between four patterns of patients with DMT2. However, there is still lack of multivariate statistical studies using DMT2 data sets to assess different aspects of the problem like optimal rapid monitoring of the patients or specific separation of patients into patterns of similarity related to their health status which could be of help in preparation of data bases for DMT2 patients. The outcome from the study could be of custom for the selection of significant tests for rapid monitoring of patients and more detailed approach to the health status of DMT2 patients.

The Upper Paleolithic man from Markina Gora: Morphology vs. genetics?

The latest results of anthropological studies of bone remains from the earliest Upper Paleolithic burial discovered on Russian territory, the Markina Gora site (Kostenki 14), are described. Multivariate statistical methods and parallel studies of the buried skull structure and dentition established that their morphological characteristics undoubtedly belonged to the Caucasian complex. In combination with paleogenetic data, the findings contradict the earlier hypothesis of the southern origin of the Kostenki 14 individual and its similarity to the population of the Australo-Melanesian region.

Biostratigraphy and biofacies of the Middle Darriwilian (Ordovician) conodonts from the Laoshidan section in the western margin of the North China Craton

Abstract Middle Ordovician conodonts from the Sandaokan and Zhuozishan formations of the Laoshidan section at the western margin of the North China Craton, consist of 39 identified and six indeterminate species belonging to 21 genera, and three taxa left in open nomenclature at both genus and species levels. Of particular biostratigraphic importance is the presence of morphologically advanced species of Histiodella associated with several age-diagnostic endemic taxa, making it possible to recognize international conodont biozones in the main part of the sequence. Three Histiodella-based zones are recognized in the studied section; including the Histiodella cf. holodentata, Histiodella kristinae and Histiodella bellburnensis zones, in ascending order. They can be directly correlated with the conodont zonations established in western Newfoundland, Canada and Tarim, western China, and compared well with the conodont biozones of Baltoscandia and Yangtze, central China. However, the same stratigraphic interval on the North China Platform is barren of conodonts. Multivariate statistical studies on these conodonts allow recognition of four conodont biofacies: Scalpellodus biofacies, Panderodus biofacies, Drepanoistodus biofacies and Phragmodus biofacies. Turnovers of the conodont biofacies are related to either sea-level changes or mixing of shallow water conodonts due to down slope transportation. Excluding the effect of the allochthonous conodonts, the transgressive-regressive patterns demonstrated by the conodont biofacies compare closely to the published sea-level curves for the western margin of the North China Craton.

Early–Middle Ordovician conodont biofacies on the Yangtze Platform margin, South China: Applications to palaeoenvironment and sea-level changes

9172 Conodonts have been recovered from the uppermost Hunghuayuan Formation and the Zitai Formation at two sections in Shitai County, southern Anhui Province, South China, which was situated close to the margin of the Lower Yangtze Platform during the Early to Middle Ordovician. Systematic and multivariate statistical studies on these conodonts permit recognition of seven conodont biofacies: Tropodus biofacies, Diaphorodus biofacies, Oepikodus biofacies, Baltoniodus biofacies, Paroistodus biofacies, Periodon biofacies and Protopanderodus biofacies. Each biofacies is restricted to a particular lithofacies and stratal position and shows a consistent order and/or position within the succession. Turnover of these conodont biofacies is related to sea-level changes. The transgressive–regressive patterns demonstrated by the conodont biofacies compare closely to published sea level curves for South China, and highlight the utility of conodont biofacies as a means of confirming sedimentological evidence of relative sea-level change.

Portfolio of Automated Trading Systems: Complexity and Learning Set Size Issues

In this paper, we consider using profit/loss histories of multiple automated trading systems (ATSs) as N input variables in portfolio management. By means of multivariate statistical analysis and simulation studies, we analyze the influences of sample size (L) and input dimensionality on the accuracy of determining the portfolio weights. We find that degradation in portfolio performance due to inexact estimation of N means and N(N - 1)/2 correlations is proportional to N/L; however, estimation of N variances does not worsen the result. To reduce unhelpful sample size/dimensionality effects, we perform a clustering of N time series and split them into a small number of blocks. Each block is composed of mutually correlated ATSs. It generates an expert trading agent based on a nontrainable 1/N portfolio rule. To increase the diversity of the expert agents, we use training sets of different lengths for clustering. In the output of the portfolio management system, the regularized mean-variance framework-based fusion agent is developed in each walk-forward step of an out-of-sample portfolio validation experiment. Experiments with the real financial data (2003-2012) confirm the effectiveness of the suggested approach.

Application of multivariate statistical analyses in the differentiation between two phosphate ores from the Nuba Mountains, Sudan

In previously published research, uranium abundance and major and trace element content were determined in phosphate ore samples from the Kurun and Uro areas of the Nuba Mountains in Sudan. The current work aims to characterise and differentiate between the phosphate ores from these two areas by subjecting the obtained geochemical data to quantitative and qualitative statistical analyses. Multivariate statistical analyses and correlation studies show several geochemical differences in the occurrence of uranium in Kurun and Uro phosphate ores. Uranium in Uro phosphate ore shows a higher degree of mobility coefficient of variability (CV% = 91) than that in Kurun phosphate ore (CV% = 48). Kurun and Uro phosphate ores are found to be good sources of titanium and strontium. The average concentrations of Ti and Sr in Uro phosphate ore are 4880 and 2780 mg kg–1, respectively. The corresponding values in Kurun phosphate ore are 7300 and 2630 mg kg–1, respectively. A cluster analysis of trace elements demonstrates that both Ti and Sr, which are the most abundant trace elements, appear in individual groups or in sub-groups. Uranium behaves in the same manner in both phosphate ores in that it associates in groups containing all the transition metals except for the most abundant trace element, titanium.

Comparison of the 2000 and 2005 spatial distributions of heavy metals in wild mussels from the North-Atlantic Spanish coast

Spatial distributions of Cd, Cu, Hg, Pb and Zn in Mytilus galloprovincialis in 41 sampling sites in the North-Atlantic Spanish coast were monitored in 2000 and 2005 to assess the coastal environmental pollution. A pool of mussel soft tissue was prepared using 50 or more individuals representing the available size range. Samples were grounded, homogenised and quantified by atomic absorption spectrometry. Quality of the chemical analyses was assessed by participation in periodic interlaboratory exercises. Univariate and multivariate statistical studies, Principal Components Analysis and Procrustes rotation (a technique intended to compare several data spaces) were carried out. Some decreasing trends were observed for the concentrations throughout the 2000–2005 period, mainly for Hg and Pb. In general, the Northern area showed higher median concentrations (e.g., 3.79 and 4.28mg Pb/kg dry weight, and 0.160 and 0.191mg Hg/kg dry weight, for 2000 and 2005, respectively) than the Atlantic ones (e.g., 1.47 and 1.44mg Pb/kg dry weight, and 0.097 and 0.084mgHg/kg dry weight, for 2000 and 2005, respectively). Nevertheless, some Atlantic sampling points, located far from human inputs (cities, industries, rivers, etc.) exhibited high concentrations of Cd, which was attributed to the influence of the natural upwelling processes which occur annually in that geographical region.

Magnetic parameters, trace elements, and multivariate statistical studies of river sediments from southeastern India: a case study from the Vellar River

This contribution constitutes a new study using magnetic parameters and trace element determinations of pollutants in river sediments from the Tamil Nadu state. The Vellar River covers a total length of about 200 km and flows into the Bay of Bengal. Sediment samples were collected at different sediment depths (up to 90 cm) from 12 sites to investigate their magnetic properties (27 samples) and the contents of trace elements (21 out of 27 samples) along the river; as well as to perform magnetic studies for various grain size fractions (16 sub samples). The magnetic results of magnetic susceptibility and remanent magnetizations suggest that the magnetic signal of these sediments is controlled by ferrimagnetic minerals magnetite-like minerals and a minor contribution of antiferromagnetic carriers (such as hematite minerals). Detailed studies of selected samples showed a higher magnetic concentration in finer grain-sized fractions and a slightly different magnetic mineralogy. Magnetic concentration-dependent parameters evidenced high values, which, together with the background values, allowed us to identify magnetic enhancement at some sites. The Pearson correlation and multivariate statistical studies (Principal Component Analysis, Canonical Correlation Analysis) supported the relationship between the magnetic and chemical variables; in particular, magnetic susceptibility, anhysteretic and isothermal remanent magnetization are closely correlated to Co, Cr, Cu, Fe, V, Zn, and the pollution load index. In addition, Principal Coordinate Analysis and fuzzy C-means cluster analysis allowed us to make a classification and to perform a magnetic-chemical characterization of the data into four groups, thereby identifying critical (possibly polluted) sites from the Vellar River.

Recent Advances in Psychopathy Research

Can J Psychiatry. 2009;54(12):787-790. The study of psychopathy is a rapidly growing area of psychiatry and psychology. The articles in this In Reviewprovide insight into 3 critical domains of psychopathy research. Taken together, they illustrate the substantial progress made in understanding psychopathy and the mechanisms that underlie it. In addition, each identifies limitations of current knowledge and suggests important directions for fixture studies. Dr Robert D Hare and Dr Craig S Neumann1 provide a good introduction to the syndrome and summarize various issues related to using the expert-rater Psychopathy Checklist (PCL) measures to assess psychopathy, and address relations between psychopathy, antisocial behaviour, and violence. In reviewing similarities and differences between psychopathy and antisocial personality disorder (ASPD), they argue persuasively that psychopathy merits a greater role in diagnostic taxonomies. Their reviews of the application of multivariate statistical methods and intervention studies are especially informative. Regarding intervention, they make the provocative argument that treatment need not alter the personality of psychopathic offenders to reduce antisocial behaviour. They also review recent findings suggesting somewhat effective treatment both of adults and of youth with psychopathic features. I comment here on only a few of these issues. First, Dr Hare and Dr Neumann' address the trend toward studying the dimensions underlying psychopathy rather than psychopathy itself. These studies raise questions about when the full psychopathy syndrome, compared with one of its components, is most useful in predicting outcomes of interest. Although they illustrate this issue within the domain of antisocial behaviour, the same issue applies to the affective, cognitive, and physiological anomalies associated with psychopathy. A related issue is that regression and structural equation modelling studies commonly report unique relations of factor scores to scores on criterion variables. However, because intercorrelations between psychopathy factor scores often account for one-half or more of the variance in a factor score, it is difficult to interpret the meaning of relations that are evident only after controlling for the influence of other factor scores.2 Substantial additional research on this issue is needed. Second, they review recent research suggesting the possibility of rater bias in assessments completed by clinicians in adversarial contexts. Given the increasing use of psychopathy in courtrooms, it is striking that so much of what we know about the disorder is based on research in which psychopathy is assessed confidentially. Evidence on the impact of biased self-presentation3 and on rater bias in adversarial contexts suggests that PCL ratings may be less reliable in forensic than in laboratory settings,4'5 another critical direction for fixture research. As Dr Hare and Dr Neumann note,1 PCL assessments that are completed based solely on file material provide a method that circumvents the need to interview defendants. However, such assessments may provide less information at higher levels of psychopathy and less adequate assessments of interpersonal-affective aspects of psychopathy.6 Whereas Dr Hare and Dr Neumann note that PCL: Youth Version (YV) scores have many of the same correlates as PCL - Revised scores, their chief focus is on psychopathy in adults. In contrast, Dr Paul J Frick7 reviews the burgeoning literature on youth with psychopathic traits. Given the probability that understanding the development of psychopathy will aid in preventing it, the past decade has seen a dramatic increase in studies of youth with psychopathic traits. Dr Frick's work occupies a pivotal place in this growing empirical literature. Instead of using expert-rater measures, Dr Frick7 focuses on studies employing parent, teacher, or self-ratings of psychopathic traits. …

Should Policy Makers Strive for Neighborhood Social Mix? An Analysis of the Western European Evidence Base

The paper presents an analytical framework for elucidating the equity and social efficiency criteria that might be used to justify a housing policy aiming for a substantial mix of neighborhood residents by income, ethnicity and/or immigrant status. This framework permits the classification of multivariate statistical studies comprising the Western European evidence base and shows the importance of distinguishing intra- and extra-neighborhood processes when evaluating evidence related to the efficiency criterion. Evaluation of the evidence base in light of this framework reveals that it sufficiently supports a mixing policy aimed at avoiding concentrations of disadvantaged individuals if, and only if, policy makers emphasize equity grounds (i.e. improving the well-being of the disadvantaged absolutely). The evidence base does not support a mixing policy on efficiency grounds, regardless of whether intra-neighborhood social interactions or extra-neighborhood stigmatization/resource restrictions are presumed to be the primary causal mechanism for neighborhood effects.

Histoire et dynamique du marécage tropical de Ndurumu (Burundi), données polliniques

This paper presents the results of the pollen analysis of two cores taken in a papyrus swamp of the Ndurumu Valley, north of Burundi (2°43′S, 29°58′E) at 1367 m of altitude. The zonation ofthe pollen record and the interpretation of pollen data are controlled by multivariate statistical studies such as the diversity index, factorial and cluster analysis. At the bottom of the core, dated around 6400 yr BP, the pollen assemblages document the installation of a pioneer forest including Macaranga and abundant ferns. Between 2800 and 1600 yr BP, the valley was occupied by a swamp forest dominated by Syzygium and Phoenix. The establishment of a papyrus swamp dates from 1250 yr BP when the forest disappeared. The abrupt disappearance of the forest is interpreted as the result of a rising water table rather than an effect of human deforestation, although a synchronous appearance of the cultivated Ricinus communis is registered at the same time.

Organizational Climate and Culture: A Conceptual Analysis of the School Workplace

The concepts of organizational climate and culture have become part of the standard rhetoric in contemporary discussions of school effectiveness. Unfortunately, both terms are complex and neither is dearly defined. This article examines the intellectual traditions and conceptual underpinnings of climate and culture and then provides working definitions for each. Examples of frameworks to study school climate and school culture are presented and contrasted. The tension between research on climate using multivariate statistical analyses and studies of culture using the tools of the phenomenologist and ethnographer provides a healthy competition, one that should enhance our understanding of the school workplace if both perspectives are given an opportunity to flourish.

Data transformations in multivariate morphometric analyses

The results of a systematic investigation of the properties of several data transformations commonly used in multivariate statistical studies of primate functional morphology are considered. Using the same sample of 11 extant primate taxa and the same set of linear measurements of the elbow complex, each transformation is examined with regard to its biological meaning and its mathematical appropriateness for use in discriminant function analysis. Discriminant function analysis has been selected for this investigation since it is the technique most often used in multivariate statistical analyses of primate functional morphology. Only three of the transformed data sets strictly meet the requirements of discriminant analysis. These are: (1) data scaled by a size measure; (2) the logarithm of the raw data; and (3) the logarithm of data transformed by an allometric correction. Discriminant analyses of the latter two data sets produce virtually identical results, separating the 11 groups primarily on the basis of size. In the discriminant analysis of the scaled data, however, the first two discriminant axes, at least, appear to separate the taxa along functionally significant lines. We recommend the use of scaled data in multivariate analyses of functional morphology for two reasons. First, scaled data meet the mathematical requirements of discriminant analysis (and most other multivariate statistical methods). In addition, scaled data, by measuring relative sizes of features, contain more information about shape (and, thus, about function) than do data transformed by other commonly used transformations.

The place of the australopithecines in human evolution: grounds for doubt?

Although most studies emphasise the similarity of the australopithecines to modern man, and suggest, therefore, that these creatures were bipedal tool-makers at least one form of which (Australopithecus africanus--"Homo habilis", "Homo africanus") was almost directly ancestral to man, a series of multivariate statistical studies of various postcranial fragments suggests other conclusions. Their locomotion may not have been like that of modern man, and may, though including a form or forms of bipedality, have been different enough to allow marked abilities for climbing. Bipedality may have arisen more than once, the Australopithecinae displaying one or more experiments in bipedality that failed. The genus Homo may, in fact, be so ancient as to parallel entirely the genus Australopithecus thus denying the latter a direct place in the human lineage.

Multiple-Discriminant Analysis of Geographical Variation in the Aquatic Beetle, Rhantus Gutticollis (Say) (Dytiscidae)

Zimmerman, James R., and John A. Ludwig (Department of Biology, New Mexico State University, Las Cruces, New Mexico 88003) 1974. Multiple discriminant analysis of geographical variation in the aquatic beetle Rhantus gutticollis (Say) (Dytiscidae). Syst. Zool. 24:63-71.-Multiple-discriminant analysis with aid of the Mahalanobis D2 statistic is a useful way of.-analyzing geographical variation in Rhantus gutticollis (Say). A moderate number of mensural characters (14) and rather small sample sizes (N 25 or 30) give results which permit discrimination to a fine degree among apparently very similar populations. The approach reveals more features of geographical variation than would probably be seen in the usual one-character comparisons. It is a widespread species with considerable regional differentiation and with well-marked boundaries between different population groups. In spite of those differences, the situation does not readily lend itself to conventional subspecific fractionation. The results from MDA are interpreted as reflections of gene flow rather than differentiation of local populations. [multiple-discriminant analysis, geographic variation, Dytiscidae, gene flow.] The problem of analyzing geographical variation within species continues to receive attention by taxonomists. For the traditional taxonomist, recognition of geographical and ecological races, clines, chromosomal differences, and polymorphs has probably been the principal means of illustrating regional variations in species. Some character differences between populations have traditionally been compared using univariate statistical procedures. Increasingly more multivariate statistical studies have been used to examine geographical variation (see the review of Gould & Johnston 1972, and Genoways & Choate 1972, Rohwer 1972, Jackson 1973, Johnston 1973, Niles 1973). Among the techniques is multiple-discriminant analysis (MDA) which includes both discriminant functions and generalized distance, or the D2 statistic. Discriminant function is a linear function that will best discriminate between two sample populations based on multiple characteristics. Generalized distance is a measure of a statistical distance between two sample populations. D2 is easily calculated using a discriminant function (Rao 1952). We wish to examine geographic variation in the aquatic beetle Rhantus gutticollis (Say) using the D2 statistic. R. gutticollis is a medium-sized species of predacious diving beetle ranging from British Columbia to Costa Rica, and from the Pacific Coast to the western edge of the Great Plains (Fig. 1). Zimmerman and Smith (In press) document the species limits and synonymy used for this paper. R. gutticollis, described by Say in 1834 from Mexico, was long unknown and usually confused with R. binotatus (Harris). Wallis (1933) recognized gutticollis and considered it as distinct from a Pacific Northwest population which he described as hoppingi. Leech and Chandler (1956) confirmed that the two forms were separable and noted the occurrence of gutticollis and hoppingi in California. Another nominal species, R. mexicanus (Aube'), has proven to be a dark polymorphic form of gutticollis which occurs throughout the southern part of the range. It differs only in its mostly black rather than the irrorated (color applied as grains of sand) elytral pattern which is found in the more common morph. The mexicanus morph is indistinguishable from the common form in the 14 characters used in this study. Intergrades (with the penis and male protarsal claws as diagnostic characters) be-