Multivariate Study (multivariate + study)

Distribution by Scientific Domains


Selected Abstracts


A comparison of catchment based salmonid habitat survey techniques in three river systems in Northern Ireland

FISHERIES MANAGEMENT & ECOLOGY, Issue 3 2002
W. C. K. O'CONNOR
Three survey techniques, a fully quantitative, multivariate study; a shorter or truncated fully quantitative method and a Geographical Information System (GIS) based, semi-quantitative, survey technique, were developed to assess in-river salmonid habitats on a catchment wide basis. These methods were tested and compared on three river systems in Northern Ireland: the Blackwater, the Bush and the Main. The research indicated that the fully quantitative method generated an accurate habitat database but required a high investment in time and resources to complete. The truncated survey approach often produced an inaccurate habitat database. The semi-quantitative technique generated a more accurate habitat dataset with greater productivity and efficiency for the resources invested in the survey. [source]


Colour characteristics of honeys as influenced by pollen grain content: a multivariate study

JOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 4 2004
Anass Terrab
Abstract A chromatic analysis by tristimulus colorimetry and a pollen analysis (pollen grains contained in each honey sample, considering their volume and geometrical shape) were carried out on 33 Eucalyptus unifloral honeys; the colour of the pollen grains was also considered. Multiple linear regression (MLR) and partial least squares regression (PLSR) were used to establish equations relating the chromatic variables to the pollen data, ie number and morphology of the pollen grains, thus allowing the prediction of the ultimate colour from the botanical characteristics. The results obtained show that lightness (L*) is significantly (p < 0.05) related to the pollen type Olea europaea; on the other hand, the variable that better relates to the chroma is the Zea mays pollen type. Copyright © 2004 Society of Chemical Industry [source]


Immunohistochemical study of the expression of adhesion molecules in ovarian serous neoplasms

PATHOLOGY INTERNATIONAL, Issue 2 2006
Eun Yoon Cho
To clarify possible roles of adhesion molecules including E-cadherin, ,- and ,-catenin, CD44s, CD44v6, CD56, and CD99 in ovarian serous neoplasms, an immunohistochemical study was undertaken for 23 benign, 40 borderline, and 95 malignant ovarian serous neoplasms using tissue microarray (TMA). Significantly reduced expression of E-cadherin, and overexpression of CD44s, CD56, and CD99 were more frequently observed in adenocarcinomas than in benign and borderline tumors. Expression of CD44v6 and nuclear ,- and ,-catenin were detected only in borderline tumors and adenocarcinomas. Reduced expression of E-cadherin was also correlated with high tumor grade (P = 0.03), presence of peritoneal seeding (P = 0.03), and low overall survival rate (P = 0.02). Overexpression of CD44s was significantly associated with high tumor grade (P = 0.04), advanced stage (P = 0.03), and low overall survival rate (P = 0.02). CD56 was increasingly expressed in the case of advanced stage (P = 0.005) and peritoneal seeding (P = 0.001). Nuclear staining for ,-catenin was correlated with tumor progression (P = 0.004) and advanced International Federation of Gynecology and Obstetrics (FIGO) stage (P = 0.02). Only CD44s expression and stage were correlated with overall survival in multivariate study. These results suggest that although E-cadherin, CD44s, CD56, and nuclear ,-catenin immunoexpression seem to be useful prognostic markers for serous neoplasm of the ovary, CD44s expression and FIGO stage are independent prognostic factors. [source]


Platelet turnover, coagulation factors, and soluble markers of platelet and endothelial activation in essential thrombocythemia: Relationship with thrombosis occurrence and JAK2 V617F allele burden,

AMERICAN JOURNAL OF HEMATOLOGY, Issue 2 2009
Eduardo Arellano-Rodrigo
Patients with essential thrombocythemia (ET) have an increased frequency of thrombosis, but the relationship of both thrombosis and JAK2 V617F allele burden with platelet turnover, acquired activated protein C resistance (aAPCR), and levels of coagulation factors and soluble markers of platelet, and endothelial activation is not well known. In 53 ET patients (26 with a history of thrombosis), reticulated platelets (RP) percentage, aAPCR, platelet tissue factor (TF) expression, and plasma levels of TF, coagulation factors, soluble P-selectin (sP-selectin), soluble CD40 ligand (sCD40L), von Willebrand factor antigen (VWF:Ag), soluble thrombomodulin (sTM), D -dimer and prothrombin fragment 1 + 2 were compared with those in matched healthy individuals and correlated with thrombosis occurrence and JAK2 mutational load. ET patients with thrombosis had significantly higher values for RP percentage, aAPCR, and levels of factors V and VIII, VWF:Ag, sP-selectin, and sCD40L than patients without thrombosis and controls. At multivariate study, RP percentage, factor V levels, and aAPCR were independently associated with an increased risk of thrombosis. Patients with JAK2 mutation had significantly lower levels of free protein S (PS) and higher levels of TF, sP-selectin, sCD40L, VWF:Ag, and sTM than those with wild-type allele. A mutant allele dosage effect (, 12%) was observed for TF, sP-selectin, sCD40L, VWF:Ag, and PS levels. These results support a role for platelet turnover, factor V, and aAPCR in the thrombosis of ET as well as the association between JAK2 V617F allele burden and either decreased free PS or increased TF and soluble markers of platelet and endothelial activation. Am. J. Hematol., 2009. © 2008 Wiley-Liss, Inc. [source]