			Home About us Contact

Clear Clustering (clear + clustering)

Distribution by Scientific Domains

Chemistry	75%

Selected Abstracts

Lipid composition of retailed organic, free-range and conventional chicken breasts

INTERNATIONAL JOURNAL OF FOOD SCIENCE & TECHNOLOGY, Issue 3 2007
Kishowar Jahan
Summary Lipid fractions of 20 retailed chicken breasts were correlated with production system: organic, corn-fed, free-range and conventional. Neutral lipid (NL), phospholipid (PL) and free fatty acids (FFA) were examined separately. Influence of production systems was found more pronounced in PL composition than NLs. Corn-fed and free-range NLs had higher contents of nutritionally beneficial eicosapentanoic acid (C20:5 n-3) and docosahexanoic acid (C22:6 n-3) than organic and conventional. Lower polyunsaturated fatty acids in organic and free-range PLs could be beneficial for tissue stability. Principal component product space for PLs showed clear clustering related to product category. In contrast, this was not observed with FFA except in the partial least square regression product space suggesting influences on NLs and PLs and FFA. PLs had lower contents of arachidonic acid than in earlier studies. Advantages were observed in lipid fractionation using advanced sorbent extraction matrices. [source]

Migration and the Reproduction of Poverty: The Refugee Camps in Jordan

INTERNATIONAL MIGRATION, Issue 2 2003
Marwan Khawaja
Summary This study examines the link between poverty and migration into and out of camps, using 1999 household survey data on the refugee camp populations in Jordan and a binomial logistic regression. The findings show a clear clustering of poverty in the camps, where about one-third of households are poor. Results from several nested regression models show that in-migration is not the cause of persistent poverty in the camps. On the other hand, human capital variables, especially education, economic activity, and "social inheritance", as well as demographic factors such as household headship and dependency rate have significant effects on poverty incidence. Some theoretical and policy implications of the findings are discussed. [source]

Facial Soft Tissue Depths in Craniofacial Identification (Part I): An Analytical Review of the Published Adult Data,

JOURNAL OF FORENSIC SCIENCES, Issue 6 2008
Carl N. Stephan Ph.D.
Abstract:, With the ever increasing production of average soft tissue depth studies, data are becoming increasingly complex, less standardized, and more unwieldy. So far, no overarching review has been attempted to determine: the validity of continued data collection; the usefulness of the existing data subcategorizations; or if a synthesis is possible to produce a manageable soft tissue depth library. While a principal components analysis would provide the best foundation for such an assessment, this type of investigation is not currently possible because of a lack of easily accessible raw data (first, many studies are narrow; second, raw data are infrequently published and/or stored and are not always shared by some authors). This paper provides an alternate means of investigation using an hierarchical approach to review and compare the effects of single variables on published mean values for adults whilst acknowledging measurement errors and within-group variation. The results revealed: (i) no clear secular trends at frequently investigated landmarks; (ii) wide variation in soft tissue depth measures between different measurement techniques irrespective of whether living persons or cadavers were considered; (iii) no clear clustering of non-Caucasoid data far from the Caucasoid means; and (iv) minor differences between males and females. Consequently, the data were pooled across studies using weighted means and standard deviations to cancel out random and opposing study-specific errors, and to produce a single soft tissue depth table with increased sample sizes (e.g., 6786 individuals at pogonion). [source]

Mass spectrometry in the characterization of ambers.

RAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 5 2008

Amber is a fossil resin constituted of organic polymers derived through complex maturation processes of the original plant resin. A classification of eight samples of amber of different geological age (Miocene to Triassic) and geographical origin is here proposed using direct mass spectrometric techniques, i.e. laser desorption ionization (LDI), atmospheric pressure chemical ionization (APCI) and atmospheric pressure photoionization (APPI), in order to obtain a fingerprint related to the amber origin. Differences and similarities were detected among the spectra with the four methods, showing quite complex spectra, full of ionic species in the mass range investigated (up to m/z 2000). The evaluation required statistical analysis involving multivariate techniques. Cluster analysis or principal component analysis (PCA) generally did not show a clear clustering with respect to the age of samples, except for the APPI method, which allowed a satisfying clustering. Using the total ion current (TIC) obtained by the different analytical approaches on equal quantities of the different amber samples and plotted against the age, the only significant correlation appeared to be that involving APPI. To validate the method, four amber samples from Cretaceous of Spain were analyzed. Also in this case a significant correlation with age was found only with APPI data. PCA obtained with TIC values from all the MS methods showed a fair grouping of samples, according to their age. Three main clusters could be detected, belonging to younger, intermediate and older fossil resins, respectively. This MS analysis on crude amber, either solid or extract, followed by appropriate multivariate statistical evaluation, can provide useful information on amber age. The best results are those obtained by APPI, indicating that the quantity of amber soluble components that can be photoionized decreases with increasing age, in agreement with the formation of highly stable, insoluble polymers. Copyright © 2008 John Wiley & Sons, Ltd. [source]