Growth status of disadvantaged urban Guatemalan children of a resettled community

This paper reports the physical growth and body composition from the first year of longitudinal study of 519 Guatemalan children, and their families, from a disadvantaged urban community consisting largely of refugees of the 1976 earthquake. Four cohorts are described, composed of children of 1,3,5, and 7 years at examination. The children are smaller, weigh less, and have reduced fat stores compared either to NCHS reference data or to upper SES Guatemalan children. Stature (or length) and head circumference deviate more from reference data than do triceps or upper arm muscle circumference. Greater deviations are found in the linear dimensions of males than of females. These children are the smallest yet described from Guatemala City, though they are slightly larger than available rural samples. This suggests a continuum of environmental effects acting upon the growth of children of differing socioeconomic levels.     

Biomass: Is it a useful tool in paleocommunity reconstruction?

In general, more of the biomass of the community is preserved than is its numerical abundance. Thus, the paleontologist, on the average, works with more of the community when biomass is used. Community characteristics such as taxon dominance and habitat proportions are at least as accurately derived from biomass as numerical abundance. The use of biomass is clearly more appropriate in describing energy flow and trophic proportions. Whenever possible, biomass should be used as a complement to numerical abundance in future paleoecologic reconstructions.     

Chemical composition of whole plant and grain and yield of nutrients in grain of five barley cultivars

Summary twenty seven field experiments were conducted to determine if there were differences between five barley cultivars in their ability to utilize soil nutrients. There were significant differences among cultivars in yield of grain and in concentration of all macro and micro nutrients examined in both the whole plant and grain.Gateway ranked the highest for the concentration of Na, Mn, and Cu in the whole plant and was among the cultivars with highest concentration of Ca, Fe, and Zn. Centennial had generally the lowest concentration of all the nutrients determined in the whole plant. For the concentrations of Na, Mg, and Cu in grain Gateway ranked highest, but ranked third for the concentrations of K, Ca, Fe, Mn, and Zn in grain. Galt had the highest K and Mg concentration and lowest Mn, Cu and Zn concentration in grain. Except for K concentration in grain, Centennial had the lowest concentrations of all other cationic nutrients in grain.Yield of grain rather than nutrient concentration was the most important criteria in determining the ranking of nutrient yields per hectare. Because of its high grain yield, Bonanza produced the largest yield of micronutrient cations and was second to Galt in production of macronutrient cations, although it was lowest in macronutrient cation concentration. Similarly, Bonanza and Galt had the lowest protein concentration, but produced the highest yield of protein per hectare.The implications for animal nutrition of different levels of nutrients between cultivars are discussed.     

Mottling phenomena and quality of grains of different genotypes of Durum wheat grown under limited irrigation conditions

Summary Field experiment was conducted to show the effect of one irrigation of 10 cm water applied to durum wheat (Triticum durum) at crown root initiation stage, active tillering stage, anthesis stage and compared them with non irrigated plot using A-206, A-28, A-1-8-8-42-1, G.W.-1 and A-23-10 genotypes under the conditions of salt affected areas having shallow saline aquifer, on quality, yield and mottling phenomena in wheat grain. Application of irrigation significantly increased the yield and decreased the per cent mottled grain and the maximum achievement was obtained when water was applied during the stage of anthesis. Non mottled grain contained higher protein than mottled grain and there were no considerable differences in other biochemical constituents. Genotype G.W.-1 stands first in its yield performance and low mottled grain.     

Carotenoid composition in milo (Sorghum vulgare) shoots as affected by phytochrome and chlorophyll

The composition of coloured carotenoids in the milo shoot was investigated quantitatively (high performance liquid chromatography) during light-mediated plastidogenesis, including the time span of photodelay as caused by medium and high light fluxes. It was found that as long as only the far-red-absorbing form of phytochrome operates, the carotenoid pattern remains virtually the same as in complete darkness (violaxanthin and lutein as major constituents, traces of -carotene). On the other hand, the pattern changes dramatically in white or red light with increasing amounts of chlorophyll (lutein and -carotene dominate, -carotene showing the strongest relative increase). Photodelay during the early phase of plastidogenesis affects the carotenoid composition strongly. Increase of neoxanthin, violaxanthin and -carotene contents are diminished while lutein accumulation proves resistant towards chlorophyll-mediated photoinhibition. The photodelay can be diminished by an appropriate light pretreatment. The data indicate that light-mediated control over carotenoid accumulation is exerted at three levels: i) a coarse control through phytochrome, ii) fine tuning in connection with chlorophyll accumulation, iii) stabilization of holocomplexes against photodecomposition.Abbreviations GG14 high fluence rate green-yellow light - HPLC high-performance liquid chromatography - Chl chlorophyll - WL_w weak white light (1200 lx) - WL_m medium flux white light (12000 lx)     

Internal P loading in lakes: A different approach to its evaluation

P release rates in five lakes were estimated from a mass balance approach and from laboratory tests. The influence of various environmental parameters on P release has been considered. The internal P loading can contribute phosphorus to overlying waters at levels comparable to the external sources (from 30 to 100%). When considering the recovery from eutrophication of the investigated lakes, the nutrient release from sediments is of critical importance.     

A multivariate study of resource partitioning in soft bottom lotic Chironomidae

For two years a community of larval chironomid midges was studied in a sandy-run portion of a fourth order natural stream in SE Ohio, U.S.A. in order to determine if the species partitioned the spatial resources. The habitat structure was simplified from ten habitat variables to three significant principal components. The three eigenvectors were easily interpreted as sediment size, sediment heterogeneity, and organic deposition. Species abundances were loaded on these axes and niche metrics examined. Strong differences in habitat preference were demonstrated for midge species on each component. Also, there were no differences in distributions for the intraspecific instars for each species tested at a given time, but for each of the instars tested, their distributions were found to change from time to time. Apparently, individuals of a species, regardless of instar, simultaneously choose the same habitat, however, the preferred habitat may shift temporally due to change in resource availability, or niche expansion or compression due to competition.     

Uridine Transport and Metabolism in the Central Nervous System

Myelin and myelin-containing (P3) fractions were prepared from human white matter by discontinuous sucrose gradient centrifugation. The myelin isolated from each of the fractions of different densities was morphologically and biochemically distinct. Light myelin fractions consisted of compact, multilamellar myelin, whereas the denser fractions consisted predominantly of loose myelin with fewer lamellae. The amounts of both basic protein and lipophilin (proteolipid protein) were reduced in the denser fractions. In contrast, the high-molecular-weight components were elevated in the dense fractions. The lipid composition was similar in all the fractions studied. Analysis of basic protein by gel electrophoresis at pH 10.6 revealed differences in basic protein microheterogeneity among the fractions. The light myelin fraction was enriched in the more positively charged basic protein components (components 1, 2, and 3), whereas these components were reduced in the denser fractions. Myelin in the dense fractions was enriched in the more modified forms of basic protein (components 6, 7, and 8). The pattern of microheterogeneity was different for basic protein isolated from myelins of a 2-year-old and an adult brain; the former showed fewer components and mainly the most cationic species. On the other hand, the pattern of microheterogeneity of basic protein isolated from the different density gradient fractions was similar for both ages.     

Enumeration and structural assessment of peritoneal macrophages during progressive protein deficiency in rats

The effects of protein malnutrition on responsiveness of macrophages to proteosepeptone stimulation and on their chemical composition were investigated. Relative number of resident macrophages in rat peritoneal cavity was reduced by about 50 % during 4 weeks on 3 % protein diet. Similarly, decreased migration capacity of the circulating macrophages to the peritoneal exudate in response to the stimulant, was observed in protein-fasted rat compared to that in the 20 % protein-fed group. Further, the chemical composition of the isolated elicited cells was determined. Total proteins, sugars, lipids and nucleic acids were significantly low in the cells isolated from protein-deficient animals, though the cell size was not affected. However, cholesterol: phospholipid molar ratios were distinctly higher than that in control and increased progressively in the 3 and 8 % protein-fed animals. The implications of these structural changes in macrophages on their functional capability are discussed     

金沙江河谷苏铁天然植物群落的研究

近年在金沙江干热河谷及其邻近地区陆续发现的苏铁天然植物群落,为本属植物在欧亚大陆内陆分布的最北边缘。其中,面积最大和保存较好的是渡口市攀枝花苏铁(Cycas panzhihuaensis)植物群落。本文研究了这个群落的分布与生境、生长状况、外貌、种类组成以及群落的综合特征等。认为具有稀树草原的特点,而这里的稀树草原是次生性质的,苏铁群落是其中幸存的残遗植被类型。这对研究我国植物地理有着重要意义。