Assimilation Patterns (assimilation + pattern)

Distribution by Scientific Domains

Selected Abstracts

Health Assimilation Patterns Amongst Australian Immigrants*

This paper compares the health of Australian immigrants with that of the Australian-born population and examines the extent to which differences vary with time since migration. Health is measured using self-reports of chronic diseases from three national health surveys. Probit models are used to estimate the health effects of immigrant arrival cohorts, years since migration and country of birth. We find that the health of Australian immigrants is better than the Australian-born population, but the longer immigrants spend in Australia, the closer their health approximates that of the Australian-born population. There are variations for different immigrant groups and for particular chronic diseases. [source]

Nitrate modifies the assimilation pattern of ammonium and urea in wheat seedlings

Maria Garnica
Abstract BACKGROUND: In certain plant species, ammonium or urea nutrition can cause negative effects on plant development which can result in toxic symptoms. Some authors suggest that the presence of nitrate can alleviate these symptoms by increasing ammonium and urea assimilation, avoiding its accumulation. In order to study this hypothesis, wheat (Triticum aestivum L.) seedlings were grown with various nitrogen supplies containing the main nitrogen forms (ammonium, nitrate and urea). Amino acids content and the activity of the three main enzymes involved in nitrogen assimilation (nitrate reductase, glutamine synthetase and urease) were studied. RESULTS: The application of nitrate along with urea and/or ammonium was not associated with a time-sustained increase in the activity of glutamine synthetase and urease. Amino acid analysis revealed that nitrate induced changes in amino acid metabolism enhancing its concentration. Likewise the content of protein was also higher in nitrate-treated plants. CONCLUSION: These results suggest that the effect of nitrate is compatible with a rapid and transient increase in the activity of glutamine synthetase and urease during the first hour after the onset of treatments. Nevertheless, a possible effect of nitrate reducing ammonium accumulation through the activation of alternative metabolic pathways different from that involving glutamine synthetase cannot be ruled out. Finally, nitrate effects on amino acid concentration indicate that, whereas ammonium assimilation takes place principally in the root, urea and nitrate assimilation occurred in the shoot, under the conditions of the experiment. Copyright © 2009 Society of Chemical Industry [source]

Dynamics of yeast populations recovered from decaying leaves in a nonpolluted stream: a 2-year study on the effects of leaf litter type and decomposition time

Ana Sampaio
Abstract Here we report on the results of a survey of the yeast populations occurring on submerged leaves (alder, eucalyptus and oak) in a natural mountain stream, during different phases of their decomposition and through two consecutive years. Leaf litter mass loss, total yeast counts, Shannon,Weiner index (H,), yeast community structure and physiologic abilities were analyzed to evaluate the dynamics of yeast communities during decay. Seventy-two yeast taxa were recorded, and in all litter types, species of basidiomycetous affinity predominated over ascomycetous ones. Discriminant analysis of presence/absence data (yeast species) showed significant differences both among substrate types (P<0.0026) and with decomposition time (P<0.0001). Carbon and nitrogen source utilization by yeast strains also varied with the substrate (P<0.0001) and decomposition time (P<0.0001). Further conclusions were that: (1) all litter types have in common ubiquitous yeast species, such as Cryptococcus albidus, Debaryomyces hansenii and Rhodotorula glutinis, among the common 20 yeast species; (2) only a few species were dominant, and most species were rare, being recorded once or twice throughout decomposition; and (3) the order of yeast appearance, and their substrate assimilation patterns, strongly suggest a succession phenomenon. Finally, explanations for the distribution patterns and variations in yeast communities are discussed. [source]

Carbon dioxide assimilation by a wetland sedge canopy exposed to ambient and elevated CO2: measurements and model analysis

D. P. Rasse
Summary 1The wetland sedge Scirpus olneyi Gray displays fast rates of CO2 assimilation and responds positively to increased atmospheric CO2 concentration. The present study was aimed at identifying the ecophysiological traits specific to S. olneyi that drive these CO2 -assimilation patterns under ambient and elevated CO2 conditions. 2The net ecosystem exchange (NEE) of CO2 between S. olneyi communities and the atmosphere was measured in open-top chambers. 3We developed a new mechanistic model for S. olneyi communities based on published ecophysiological data and additional measurements of photosynthetic parameters. 4Our NEE measurements confirmed that S. olneyi communities have a high rate of summertime CO2 assimilation, with noontime peaks reaching 40 µmol CO2 m,2 ground s,1 on productive summer days, and that elevated CO2 increased S. olneyi CO2 assimilation by c. 35,40%. 5Using S. olneyi -specific ecophysiological parameters, comparison with measured NEE showed that the model accurately simulated these high rates of CO2 uptake under ambient or elevated CO2. 6The model pointed to the Rubisco capacity of Scirpus leaves associated with their high total nitrogen content as the primary explanation for the high rates of CO2 assimilation, and indicated that the vertical-leaf canopy structure of S. olneyi had comparatively little influence on CO2 assimilation. [source]

Yeast associated with human infections in south-eastern Nigeria

MYCOSES, Issue 6 2006
L. N. Abia-Bassey
Summary A total of 1921 specimens from nine clinical sources were examined by direct microscopy and culture to recover yeast associated with human infection. Identification of yeast was based on their carbon assimilation patterns, using API 20C AUX and ID 32 C (bioMérieux, France) commercial kits. A total of 178 specimens (9.3%) were positive for yeast. Most of the yeast isolates were recovered from urine samples and genital swabs. Prevalence was significantly higher in women (14.7%) than in men (1.4%) (P < 0.05). The age group 21,30 years recorded the highest prevalence of yeast infection (65.2%) followed by age group 11,20 years (16.9%) and >40 years (9.0%). When genital samples were considered, prevalence was significantly higher in the age group 21,30 years than that in older ones (P < 0.05). Isolates recovered included seven species of Candida and Trichosporon inkin. C. albicans accounted for the highest number of isolates (128) followed by C. tropicalis (23) and C. parapsilosis (9). Two isolates each of C. famata and C. norvegensis were recorded and are reported for the first time in Nigeria. The two isolates of T. inkin were recovered from perianal lesions and are also reported for the first time from Nigeria. C. albicans, C. glabrata, C. parapsilosis and C. krusei were found to be the most common yeast species that act as agents of human disease in south-eastern Nigeria. [source]

The Role of Religion in the Postwar Settlement Patterns of Dutch Canadians,

Joanne van Dijk
Dans cet article, nous examinons l'influence de la religion sur les modèles de colonies de peuplement des Hollandais au Canada après la guerre. D'après les données historiques, des différences existaient dans l'assimilation des catholiques hollandais et des calvinistes hollandais au Canada. Lorsque les immigrants hollandais sont arrivés au Canada au début des années cinquante, les catholiques se sont inté-grés aux églises et aux écoles catholiques existantes alors que les calvinistes orthodoxes ont entrepris de forger leurs propres structures sociales et culturelles, car, selon eux, les institutions canadiennes ne reflétaient pas leurs croyances idéologiques et religieuses. La religion a joué un rôle important dans l'émergence de communautés hollando-canadiennes contrastées. Nous partons du modèle de pluralisme et d'intégration volontaires de Driedger (1996: 39) afin d'élaborer le cadre théorique de cet article. In this paper the influence of religion on the postwar settlement patterns of Dutch-Canadian immigrants is examined. Historical data show that there were differences in the assimilation patterns of Dutch Catholics and Dutch Calvinists within Canada. When Dutch immigrants arrived in Canada in the early 1950s, the Dutch Catholics joined existing Catholic churches and schools, while the orthodox Dutch Calvinists undertook the building of their own social and cultural structures because they could not find Canadian organizations based on their ideological and religious beliefs. Religion played an important role in the emergence of contrasting Dutch-Canadian communities. Driedger's (1996:39) model of voluntary pluralism and integration provides the theoretical framework for this study. [source]