Temperature and biomass influences on interannual changes in CO2 exchange in an alpine meadow on the Qinghai-Tibetan Plateau

Three years of eddy covariance measurements were used to characterize the seasonal and interannual variability of the CO2 fluxes above an alpine meadow (3250 m a.s.l.) on the Qinghai-Tibetan Plateau, China. This alpine meadow was a weak sink for atmospheric CO2, with a net ecosystem production (NEP) of 78.5, 91.7, and 192.5 g C m(-2) yr(-1) in 2002, 2003, and 2004, respectively. The prominent, high NEP in 2004 resulted from the combination of high gross primary production (GPP) and low ecosystem respiration (R-e) during the growing season. The period of net absorption of CO2 in 2004, 179 days, was 10 days longer than that in 2002 and 5 days longer than that in 2003. Moreover, the date on which the mean air temperature first exceeded 5.0 degrees C was 10 days earlier in 2004 (DOY110) than in 2002 or 2003. This date agrees well with that on which the green aboveground biomass (Green AGB) started to increase. The relationship between light-use efficiency and Green AGB was similar among the three years. In 2002, however, earlier senescence possibly caused low autumn GPP, and thus the annual NEP, to be lower. The low summertime R-e in 2004 was apparently caused by lower soil temperatures and the relatively lower temperature dependence of R-e in comparison with the other years. These results suggest that (1) the Qinghai-Tibetan Plateau plays a potentially significant role in global carbon sequestration, because alpine meadow covers about one-third of this vast plateau, and (2) the annual NEP in the alpine meadow was comprehensively controlled by the temperature environment, including its effect on biomass growth.

Social and ecological influences on dispersal and philopatry in the plateau pika (Ochotona curzoniae)

Benefits and costs of dispersal and philopatry of the social plateau pika (Ochotona curzoniae) were studied on the Tibetan plateau for 3 years. Although short-lived, plateau pikas live in cohesive family groups that occupy burrow systems in sedge meadow habitat Most (57.8%) plateau pikas were philopatric, and dispersal movements were extremely restricted. No juvenile females or adult pikas moved more than two family ranges between years; the greatest observed dispersal distances were by two juvenile males that moved five family ranges from the family of their birth. Traversing unfamiliar habitat was not a cost of pika dispersal because most dispersers settled in families that they could easily visit before dispersal. Dispersal movements appeared to result in equalization of density among pika families, an expected result if competition for environmental resources influenced dispersal. Males did not disperse to gain advantages in competition for mates, as evidenced by their moving to families with significantly fewer females. Females, however, moved to families with significantly more males. Males provide abundant paternal care, and significantly more offspring per female survived to become adults from families with more adult males per adult female. Evidence concerning the influence of inbreeding avoidance on natal dispersal was indirect. Some males exhibited natal philopatry; thus some families had opportunity for close inbreeding. Males and females that dispersed had no opposite-sex relatives in their new families. Philopatric pikas may have benefited by remaining in families that exhibited low local densities, and philopatric females might have benefited from social cooperation with relatives.

Contextual Influences on Saliency

This article describes a model for including scene/context priors in attention guidance. In the proposed scheme, visual context information can be available early in the visual processing chain, in order to modulate the saliency of image regions and to provide an efficient short cut for object detection and recognition. The scene is represented by means of a low-dimensional global description obtained from low-level features. The global scene features are then used to predict the probability of presence of the target object in the scene, and its location and scale, before exploring the image. Scene information can then be used to modulate the saliency of image regions early during the visual processing in order to provide an efficient short cut for object detection and recognition.

Ben Marais (1909-1999): The influences on and heritage of a South African Prophet during two periods of transformation

University of Pretoria / Dissertation / Department of Church History and Church Policy / Advised by Prof J W Hofmeyr

Affective and Experiential Influences on English Skills of Heritage Spanish Speakers

Gemstone Team GABS (Grammar Acquisition in Bilingual Students)

Sociocultural and socioeconomic influences on type 2 diabetes risk in overweight/obese African-American and Latino-American children and adolescents.

PURPOSE: It is unclear whether sociocultural and socioeconomic factors are directly linked to type 2 diabetes risk in overweight/obese ethnic minority children and adolescents. This study examines the relationships between sociocultural orientation, household social position, and type 2 diabetes risk in overweight/obese African-American (n = 43) and Latino-American (n = 113) children and adolescents. METHODS: Sociocultural orientation was assessed using the Acculturation, Habits, and Interests Multicultural Scale for Adolescents (AHIMSA) questionnaire. Household social position was calculated using the Hollingshead Two-Factor Index of Social Position. Insulin sensitivity (SI), acute insulin response (AIRG) and disposition index (DI) were derived from a frequently sampled intravenous glucose tolerance test (FSIGT). The relationships between AHIMSA subscales (i.e., integration, assimilation, separation, and marginalization), household social position and FSIGT parameters were assessed using multiple linear regression. RESULTS: For African-Americans, integration (integrating their family's culture with those of mainstream white-American culture) was positively associated with AIRG (β = 0.27 ± 0.09, r = 0.48, P < 0.01) and DI (β = 0.28 ± 0.09, r = 0.55, P < 0.01). For Latino-Americans, household social position was inversely associated with AIRG (β = -0.010 ± 0.004, r = -0.19, P = 0.02) and DI (β = -20.44 ± 7.50, r = -0.27, P < 0.01). CONCLUSIONS: Sociocultural orientation and household social position play distinct and opposing roles in shaping type 2 diabetes risk in African-American and Latino-American children and adolescents.

Age and gender influences on sensory perceptions of novel low cost nutrient-rich food products developed using traditional Ghanaian food ingredients

Background: A number of factors are known to influence food preferences and acceptability of new products. These include their sensory characteristics and strong, innate neural influences. In designing foods for any target group, it is important to consider intrinsic and extrinsic characteristics which may contribute to palatability, and acceptability of foods. Objective: To assess age and gender influences on sensory perceptions of novel low cost nutrient-rich food products developed using traditional Ghanaian food ingredients. Materials and Methods: In this study, a range of food products were developed from Ghanaian traditional food sources using the Food Multimix (FMM) concept. These products were subjected to sensory evaluation to assess the role of sensory perception on their acceptability among different target age groups across the life cycle (aged 11-68 years olds) and to ascertain any possible influences of gender on preference and choice. Variables including taste, odour, texture, flavour and appearance were tested and the results captured on a Likert scale and scores of likeness and acceptability analysed. Multivariate analyses were used to develop prediction models for targeted recipe development for different target groups. Multiple factor analysis of variance (ANOVA) and logistic linear regression were employed to test the strength of acceptability and to ascertain age and gender influences on product preference. Results: The results showed a positive trend in acceptability (r = 0.602) which tended towards statistical significance (p = 0.065) with very high product favourability rating (91% acceptability; P=0.005). However, age [odds ratios=1.44 (11-15 years old) odds ratios=2.01 (18-68 years old) and gender (P=0.000)] were major influences on product preference with children and females (irrespective of age) showing clear preferences or dislike of products containing certain particular ingredients. Conclusion: These findings are potentially useful in planning recipes for feeding interventions involving different vulnerable and target groups.