Variety and total number of food items recorded by a true longitudinal group of urban black South African children at five interceptions between 1995 and 2003: the Birth-to-Twenty (Bt20) Study

OBJECTIVE: To report on the variety and total number of food items recorded by a true longitudinal group of urban black South African children (n = 143) from the Birth-to-Twenty Study at five interceptions at the ages of 5 (1995), 7 (1997), 9 (1999), 10 (2000) and 13 (2003) years, respectively. METHODS: Dietary intake was assessed using a semi-quantitative food-frequency questionnaire. Frequencies were calculated per week, for each interception and for all five interceptions combined, using SAS. RESULTS: Five hundred and forty-six different individual food items were recorded 23 480 times for all five interceptions combined. The highest of 124 items was recorded in 1999 contributing 23% of the 546 items recorded. Each of the top 10 items (rice, stiff maize-meal porridge, chicken, sugar, sweets, tea, eggs, full-cream milk, carbonated beverages and oil) contributed between 2.5% and 3% and these items were recorded almost 600 times or more for all interceptions combined (n = 23 840). Rice and stiff maize-meal porridge were the top items recorded 684 and 676 times, both contributing 2.87% and 2.84%, respectively. The variety of food items and the ratio of the food groups to the total number of foods recorded in the present study were not significantly different but the denominators decreased over the five interceptions. CONCLUSION: The variety of food items recorded did not vary between 1995 and 2003 - the fact that new items were not added to the questionnaire as the children grew older could have contributed to this phenomenon. However, there was a difference in the ranking of these items that may suggest a change in eating patterns.     

Energy, macro- and micronutrient intake among a true longitudinal group of South African adolescents at two interceptions (2000 and 2003): the Birth-to-Twenty (Bt20) Study

OBJECTIVE: This study reports on the energy, macro- and micronutrient intakes of a true longitudinal group of 143 urban black South African children from the Birth-to-Twenty (Bt20) study at two interceptions (2000 and 2003) when they were 10 and 13 years old, respectively. METHODS: Subjects resided in the urban Johannesburg/Soweto area of the Gauteng Province in South Africa. Dietary intake was assessed using a semi-quantitative food-frequency questionnaire. The coded data were analysed using SAS. RESULTS: Mean daily intake of energy, all six macronutrients and most micronutrients (17/19) increased from 2000 to 2003. Of the 19 micronutrients investigated, the mean daily intake of eight (calcium, iron, zinc, vitamin A, riboflavin, nicotinic acid, pantothenic acid and biotin) fell below the recommended dietary allowance (RDA) at both interceptions. More than 70% of the children consumed less than the RDA for these same eight nutrients. From 2000 to 2003, there was a decrease in the percentage of children falling below the RDA for energy (from 73 to 59%), but an increase in the percentage of children falling below the RDA for most of the micronutrients. There was a positive percentage change in mean daily intake for all 26 macro- and micronutrients from 2000 to 2003. CONCLUSION: Mean daily intake of nutrients increased from 2000 to 2003, but intakes for most micronutrients were still below the RDA at both interceptions for a large percentage of the children. The study has provided valuable information on the nutrient intake and change in intake over time among a longitudinal group of South African adolescents.     

Apparent Rapid Loss of Endocrine Disruptors from Wetlands Used to Store Either Tertiary Treated Sewage Effluent or Stormwater Runoff

The disruption of endocrine systems due to environmental contaminants potentially impacts on the developmental, behavioural, regulatory and reproductive systems of animals. A major source of exposure of animals (terrestrial and aquatic) to endocrine-disrupting compounds is through contact with contaminated surface waters contaminated with sewage effluent and/or stormwater discharge. We studied the response to endocrine-disrupting compounds of Gambusia holbrooki mosquito fish resident of wetlands that were used for the storage of either treated sewage effluent or stormwater runoff. We found that fish from wetlands that received polluted waters directly from the source (treated sewage effluent or stormwater runoff) demonstrated a morphological response consistent with endocrine disruption. In contrast, fish in the second in the series of wetlands that housed treated sewage effluent did not show evidence of such response. However, those from the second in the series of stormwater receiving wetlands did display a morphological response, although it could be considered milder than was observed in fish from the first in this effluent stream. Fish were also smaller in the wetland that received sewage effluent directly from the sewage treatment plant than elsewhere. Although the differences were not statistically significant, the average size of fish in the first in the series of stormwater wetlands were also small and second only to those in the first sewage effluent wetland.     

Comparison of children's diets as reported by the child via the Youth/Adolescent Questionnaire and the parent via the Willett food-frequency questionnaire

OBJECTIVE: A comparison of a parent-completed Willett food-frequency questionnaire (FFQ) and a self-completed Youth/Adolescent Questionnaire (YAQ) has not yet been conducted. SETTING: In the Diabetes Autoimmunity Study in the Young (DAISY), parents report their child's diet on the FFQ annually from birth until age 10 years, when the child begins to report their own diet using the YAQ. SUBJECTS: To determine the comparability of these collection methods, 89 children aged 10-17 years and their parents completed the YAQ and FFQ, respectively, for the child's previous year's diet. DESIGN: We compared reported intakes for energy, the macronutrients and a variety of micronutrients of interest to the DAISY study. RESULTS: Bland-Altman plots of energy-adjusted differences between questionnaire responses against their means suggested that the two collection methods gave similar results. The average Spearman correlation coefficient of all energy-adjusted nutrient intakes was 0.50, and did not differ significantly by gender (males, r=0.48; females, r=0.46) or age (10-11 years, r=0.49; 12-17 years, r=0.51). While correlated, the nutrient values from the FFQ were higher than the nutrient values from the YAQ. CONCLUSIONS: While reported nutrient intakes are correlated, an indicator variable defining which survey method a nutrient was collected with should be included in any longitudinal data analyses examining nutrient intakes collected with the YAQ and the FFQ as independent predictors of a disease outcome.     

膜下滴灌制种玉米需水量与需水规律的研究

[目的]定位监测高产膜下滴灌制种玉米田间土壤水分动态变化,为膜下滴灌制种玉米拔节后水分管理提供理论依据.[方法]采用时域反射仪(TDR)对膜下滴灌制种玉米田间土壤水分动态变化连续监测并分析干物质的积累情况,运用水分平衡法计算膜下滴灌制种玉米各生育时期耗水量和水分生产率.[结果]拔节期至灌浆期45d左右是玉米耗水高峰期,日平均耗水强度为6.4 mm;灌浆期日耗水强度为3.2 mm.[结论]制种玉米拔节后根区的土壤体积含水量总是维持在23.5;～31.4;(田间持水量的60;～80;).     

The Seismic Structure of the Sun

Global Oscillation Network Group data reveal that the internal structure of the sun can be well represented by a calibrated standard model. However, immediately beneath the convection zone and at the edge of the energy-generating core, the sound-speed variation is somewhat smoother in the sun than it is in the model. This could be a consequence of chemical inhomogeneity that is too severe in the model, perhaps owing to inaccurate modeling of gravitational settling or to neglected macroscopic motion that may be present in the sun. Accurate knowledge of the sun's structure enables inferences to be made about the physics that controls the sun; for example, through the opacity, the equation of state, or wave motion. Those inferences can then be used elsewhere in astrophysics.     

The Quantum Event of Oceanic Crustal Accretion: Impacts of Diking at Mid-Ocean Ridges

Seafloor diking-eruptive events represent the irreducible, quantum events of upper oceanic crustal accretion. They record events by which a large portion of the oceanic crust has formed through geological history. Since 1993, the U.S. Navy's real-time Sound Surveillance System has allowed location of ongoing acoustic signatures of dike emplacement and basalt eruptions at ridge crests in the northeast Pacific. These diking-eruptive events trigger a sequence of related, rapidly evolving physical, chemical, and biological processes. Magmatic volatiles released during these events may provide nutrients for communities of subseafloor microorganisms, some of which thrive in high-temperature anaerobic environments. Many of the organisms identified from these systems are Archaea. If microorganisms can thrive in the water-saturated pores and cracks within deep, volcanically active portions of our planet, other hydrothermally active planets may harbor similar life forms.     

Off-axis crustal thickness across and along the east pacific rise within the MELT area

Wide-angle seismic data along the Mantle Electromagnetic and Tomography (MELT) arrays show that the thickness of 0.5- to 1. 5-million-year-old crust of the Nazca Plate is not resolvably different from that of the Pacific Plate, despite an asymmetry in depth and gravity across this portion of the East Pacific Rise. Crustal thickness on similarly aged crust on the Nazca plate near a magmatically robust part of the East Pacific Rise at 17 degrees15'S is slightly thinner (5.1 to 5.7 kilometers) than at the 15 degrees55'S overlapping spreading center (5.8 to 6.3 kilometers). This small north-south off-axis crustal thickness difference may reflect along-axis temporal variations in magma supply, whereas the across-axis asymmetry in depth and gravity must be caused by density variations in the underlying mantle.     

The Current State of Solar Modeling

Data from the Global Oscillation Network Group (GONG) project and other helioseismic experiments provide a test for models of stellar interiors and for the thermodynamic and radiative properties, on which the models depend, of matter under the extreme conditions found in the sun. Current models are in agreement with the helioseismic inferences, which suggests, for example, that the disagreement between the predicted and observed fluxes of neutrinos from the sun is not caused by errors in the models. However, the GONG data reveal subtle errors in the models, such as an excess in sound speed just beneath the convection zone. These discrepancies indicate effects that have so far not been correctly accounted for; for example, it is plausible that the sound-speed differences reflect weak mixing in stellar interiors, of potential importance to the overall evolution of stars and ultimately to estimates of the age of the galaxy based on stellar evolution calculations.     

栽培因素对北方粳稻产量及米质的影响——第10报不同叶龄秧苗对产量及米质的影响

通过不同秧龄秧苗对水稻生育和米质的影响试验,结果表明:插秧秧龄越大株高增高,叶龄和有效穗数增加,但千粒重有降低的趋势。3.5和4.5叶龄插秧时每穗粒数最多、产量最高。插秧秧龄大,加工品质差,外观品质变坏,但食味品质提高。