Thorium-uranium fractionation by garnet: evidence for a deep source and rapid rise of oceanic basalts

Mid-ocean ridge basalts (MORBs) and ocean island basalts (QIBs) are derived by partial melting of the upper mantle and are marked by systematic excesses of thorium-230 activity relative to the activity of its parent, uranium-238. Experimental measurements of the distribution of thorium and uranium between the melt and solid residue show that, of the major phases in the upper mantle, only garnet will retain uranium over thorium. This sense of fractionation, which is opposite to that caused by clinopyroxene-melt partitioning, is consistent with the thorium-230 excesses observed in young oceanic basalts. Thus, both MORBs and QIBs must begin partial melting in the garnet stability field or below about 70 kilometers. A calculation shows that the thorium-230-uranium-238 disequilibrium in MORBs can be attributed to dynamic partial melting beginning at 80 kilometers with a melt porosity of 0.2 percent or more. This result requires that melting beneath ridges occurs in a wide region and that the magma rises to the surface at a velocity of at least 0.9 meter per year.     

Regeneration in crustacean motoneurons: evidence for axonal fusion

Crayfish motor axons remain excitable for over 100 days after severance from their central cell bodies, and continue to store and release normal amounts of transmitter substance. Evidence indicates that regeneration occurs by fusion of the central process with its surviving peripheral segment.     

Human urine and/or plasma levels of methionine,methionine sulfoxide,and inorganic sulfate after consumption of a soy isolate: A preliminary study

In a preliminary study, three human subjects consumed 35 or 70g of a commercially available soy isolate containing 298 or 596 mg of methionine sulfoxide. Methionine sulfoxide appeared in human plasma within one hour after consumption of the isolate. This observation suggests rapid absorption by humans of this oxidized form of methionine. Plasma levels of sulfoxide as determined in one subject returned to zero within 24 hours of consumption of the isolate. Ingested methionine sulfoxide was excreted in the urine in free form in very small quantities relative to intake. These results are consistent with, but of course do not prove, utilization of methionine sulfoxide as a methionine replacement in human subjects.     

Effect of grazing severity on perennial ryegrass herbage production and sward structural characteristics throughout an entire grazing season

The objective of this study, which was part of a larger grazing‐systems experiment, was to investigate the cumulative impact of three levels of grazing intensity on sward production, utilization and structural characteristics. Pastures were grazed by rotational stocking with Holstein–Friesian dairy cows from 10 February to 18 November 2009. Target post‐grazing heights were 4·5 to 5 cm (high; H), 4 to 4·5 cm (intermediate; I) and 3·5 to 4 cm (low; L). Detailed sward measurement were undertaken on 0·08 of each farmlet area. There were no significant treatment differences in herbage accumulated or in herbage harvested [mean 11·3 and 11·2 t dry matter (DM) ha^?1 respectively]. Above the 3·5 cm horizon, H, I and L swards had 0·56, 0·62 and 0·67 of DM as leaf and 0·30, 0·23 and 0·21 of DM as stem respectively. As grazing severity increased, tiller density of grass species other than perennial ryegrass (PRG) decreased (from 3,350 to 2,780 and to 1771 tillers m^?2 for H, I and L paddocks respectively) and the rejected area decreased (from 0·27 to 0·20 and to 0·10 for H, I and L paddocks respectively). These results indicate the importance of grazing management practice on sward structure and quality and endorse the concept of increased grazing severity as a strategy to maintain high‐quality grass throughout the grazing season. The findings are presented in the context of the need for intensive dairy production systems to provide greater quantities of high‐quality pasture over an extended grazing season, in response to policy changes with the abolition of EU milk quotas.     

Does living in an urban environment confer advantages for childhood nutritional status? Analysis of disparities in nutritional status by wealth and residence in Angola, Central African Republic and Senegal

OBJECTIVE: The purpose of this paper is to examine the relationship between childhood undernutrition and poverty in urban and rural areas. DESIGN: Anthropometric and socio-economic data from Multiple Indicator Cluster Surveys in Angola-Secured Territory (Angola ST), Central African Republic and Senegal were used in this analysis. The population considered in this study is children 0-59 months, whose records include complete anthropometric data on height, weight, age, gender, socio-economic level and urban or rural area of residence. In addition to simple urban/rural comparisons, the population was stratified using a wealth index based on living conditions and asset ownership to compare the prevalence, mean Z-score and odds ratios for stunting and wasting. RESULTS: In all cases, when using a simple urban/rural comparison, the prevalence of stunting was significantly higher in rural areas. However, when the urban and rural populations were stratified using a measure of wealth, the differences in prevalence of stunting and underweight in urban and rural areas of Angola ST, Central African Republic and Senegal disappeared. Poor children in these urban areas were just as likely to be stunted or underweight as poor children living in rural areas. The odds ratio of stunting in the poorest compared with the richest quintile was 3.4, 3.2 and 1.5 in Angola ST, Senegal and Central African Republic, respectively. CONCLUSIONS: This paper demonstrates that simple urban/rural comparisons mask wide disparities in subgroups according to wealth. There is a strong relationship between poverty and chronic undernutrition in both urban and rural areas; this relationship does not change simply by living in an urban environment. However, urban and rural living conditions and lifestyles differ, and it is important to consider these differences when designing programmes and policies to address undernutrition.