127,232 research outputs found
Dietary Protein Intake in Young Children in Selected Low-Income Countries Is Generally Adequate in Relation to Estimated Requirements for Healthy Children, Except When Complementary Food Intake Is Low.
Background: Previous research indicates that young children in low-income countries (LICs) generally consume greater amounts of protein than published estimates of protein requirements, but this research did not account for protein quality based on the mix of amino acids and the digestibility of ingested protein.Objective: Our objective was to estimate the prevalence of inadequate protein and amino acid intake by young children in LICs, accounting for protein quality.Methods: Seven data sets with information on dietary intake for children (6-35 mo of age) from 6 LICs (Peru, Guatemala, Ecuador, Bangladesh, Uganda, and Zambia) were reanalyzed to estimate protein and amino acid intake and assess adequacy. The protein digestibility-corrected amino acid score of each child's diet was calculated and multiplied by the original (crude) protein intake to obtain an estimate of available protein intake. Distributions of usual intake were obtained to estimate the prevalence of inadequate protein and amino acid intake for each cohort according to Estimated Average Requirements.Results: The prevalence of inadequate protein intake was highest in breastfeeding children aged 6-8 mo: 24% of Bangladeshi and 16% of Peruvian children. With the exception of Bangladesh, the prevalence of inadequate available protein intake decreased by age 9-12 mo and was very low in all sites (0-2%) after 12 mo of age. Inadequate protein intake in children <12 mo of age was due primarily to low energy intake from complementary foods, not inadequate protein density.Conclusions: Overall, most children consumed protein amounts greater than requirements, except for the younger breastfeeding children, who were consuming low amounts of complementary foods. These findings reinforce previous evidence that dietary protein is not generally limiting for children in LICs compared with estimated requirements for healthy children, even after accounting for protein quality. However, unmeasured effects of infection and intestinal dysfunction on the children's protein requirements could modify this conclusion
Statistics of Titan's South Polar Tropospheric Clouds
We present the first long-term study of the behavior of the sporadically observed tropospheric clouds recently discovered near Titan's south pole. We find that one or more small individual cloud systems is present in the 70°-80° south region during every night of observation. These clouds account for 0.5%-1% of Titan's 2.0 μm flux, consistent with a global cloud cover fraction of 0.2%-0.6%. Clouds observed over multiple-night observing periods remained nearly fixed in brightness and position with respect to Titan's surface. The continual presence of south polar clouds is consistent with the hypothesis that surface heating during the long period of continuous polar sunlight at the time of Titan's southern summer solstice drives seasonal convection and cloud formation at the pole
Similarities in Evasive Behavior of Wolf Spiders (Araneae: Lycosidae), American Toads (Anura: Bufonidae) and Ground Beetles (Coleopterea: Carabidae)
(excerpt) While collecting newly metalnorphosed American toads, Bufo anlericanus Holbrook, we have observed that they exhibited evasive behavior similar to that of adults of the wolf spiders, Pardosa saxatilis (Hentz), Pirata insularis Emerton, Pirata arerzicola Emerton, Pirata piratica (Oliver), and adults of the ground beetle, Elaplrrus ruscarius Say. When pursued or disturbed, the spiders, beetles and toads ran across the pound rapidly for short distances (ca. 1-50 cm). They then stopped abruptly and remained motionless. If they were further pursued, this escape sequence was repeated in the same or another direction. Toads and spiders occasionally moved to shallow water to avoid capture. Spiders ran across the water surface whereas the toads swam partially submerged. N\u27e observed this resemblance in evasive behavior on numerous occasions at ponds on the south edge of Carbondale, Illinois (spiders and toads), 1 krn west of Grinnell, Iowa (spiders and toads), and 1.5 km west of Bloomington, Illinois (spiders, toads and beetles). (Specimens were collected for identification from the latter site.
Effects of protein or amino-acid supplementation on the physical growth of young children in low-income countries.
Child growth stunting is common in low-income countries, possibly due to insufficient protein intakes. Most previous studies have concluded that children's protein intakes are adequate in relation to estimated requirements, but these studies did not consider issues of protein digestibility and effects of infection on dietary protein utilization. Using an alternative approach to assess the possible role of protein inadequacy in children's growth restriction, the results of 18 intervention trials in which supplementary protein or amino acids were provided to children ages 6-35 months and growth outcomes were reviewed. Eight studies conducted in hospitalized children recovering from acute malnutrition found that the recommended protein intake levels for healthy children supported normal growth rates, but higher intakes were needed for accelerated rates of "catch-up" growth. Ten community-based studies did not demonstrate a consistent benefit of supplemental protein on children's growth. However, weaknesses in the study designs limit the conclusions that can be drawn from these studies, and additional appropriately designed trials are needed to answer this question definitively. Recommendations for optimizing future study designs are provided herein
Tentative Detection of the Rotation of Eris
We report a multi-week sequence of B-band photometric measurements of the
dwarf planet Eris using the {\it Swift} satellite. The use of an observatory in
low-Earth orbit provides better temporal sampling than is available with a
ground-based telescope. We find no compelling evidence for an unusually slow
rotation period of multiple days, as has been suggested previously. A
1.08 day rotation period is marginally detected at a modest level of
statistical confidence (97%). Analysis of the combination of the
data with the ground-based B-band measurements of \citet{2007AJ....133...26R}
returns the same period (1.08 day) at a slightly higher statistical
confidence (99%).Comment: Accepted to Icarus 2008-Aug-19. 19 pages total, including 4 figures
and 1 tabl
The Formation of High-Mass Black Holes in Low Mass X-ray Binaries
In this note we suggest that high-mass black holes; i.e., black holes of
several solar masses, can be formed in binaries with low-mass main-sequence
companions, provided that the hydrogen envelope of the massive star is removed
in common envelope evolution which begins only after the massive star has
finished He core burning. That is, the massive star is in the supergiant stage,
which lasts only years, so effects of mass loss by He winds are
small. Since the removal of the hydrogen envelope of the massive star occurs so
late, it evolves essentially as a single star, rather than one in a binary.
Thus, we can use evolutionary calculations of Woosley & Weaver (1995) of single
stars. We find that the black holes in transient sources can be formed from
stars with ZAMS masses in the interval 20-35\msun. The black hole mass is
only slightly smaller than the He core mass, typically \sim 7\msun.Comment: 19 pages, substantial changes, accepted in New Astronom
Evolution and Merging of Binaries with Compact Objects
In the light of recent observations in which short gamma-ray bursts are
interpreted as arising from black-hole(BH), neutron-star(NS) or NS-NS mergings
we would like to review our research on the evolution of compact binaries,
especially those containing NS's. These were carried out with predictions for
LIGO in mind, but are directly applicable to short gamma-ray bursts in the
interpretation above.
Most important in our review is that we show that the standard scenario for
evolving NS-NS binaries always ends up with a low-mass BH (LMBH), NS binary.
Bethe and Brown (1998) showed that this fate could be avoided if the two giants
in the progenitor binary burned He at the same time, and that in this way the
binary could avoid the common envelope evolution of the NS with red giant
companion which sends the first born NS into a BH in the standard scenario. The
burning of He at the same time requires, for the more massive giants such as
the progenitors of the Hulse-Taylor binary NS that the two giants be within 4%
of each other in ZAMS mass. Applying this criterion to all binaries results in
a factor 5 of LMBH-NS binaries as compared with NS-NS binaries.
Our scenario of NS-NS binaries as having been preceded by a double He-star
binary is collecting observational support in terms of the nearly equal NS
masses within a given close binary.Comment: 32 pages, 1 figure, substantial changes from v
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