7,040 research outputs found
Behind at the Starting Line: Poverty Among Hispanic Infants
In this brief, authors Daniel Lichter, Scott Sanders, and Kenneth Johnson examine the economic circumstances of Hispanic infants using the Census Bureau’s American Community Survey annual microdata files from 2006 through 2010. They report that a disproportionate share of Hispanic infants start life’s race behind the starting line, poor and disadvantaged—an important finding because the proportion of all U.S. births that are Hispanic is growing rapidly. The poverty risk is especially high among rural Hispanic infants and those in new destinations. Despite higher poverty risks, Hispanic infants receive less governmental assistance. High Hispanic infant poverty has immediate and long-term consequences for infants and the nation. Failing to invest in families and children now has long-term consequences because early childhood poverty tends to set into motion a series of lifecycle disadvantages (such as insufficient parenting, bad neighborhoods, underfunded schools, and poor health care) that greatly increases the likelihood of poverty in adulthood. The authors conclude that whether today’s Hispanic children will assimilate into America’s economic mainstream is an open question, but the Hispanic infants who will help reshape America’s future require public policy attention now
Classical and quantum fingerprinting with shared randomness and one-sided error
Within the simultaneous message passing model of communication complexity,
under a public-coin assumption, we derive the minimum achievable worst-case
error probability of a classical fingerprinting protocol with one-sided error.
We then present entanglement-assisted quantum fingerprinting protocols
attaining worst-case error probabilities that breach this bound.Comment: 10 pages, 1 figur
Working poverty is a widespread but under-analyzed and poorly-measured problem in the US
Data and statistics are integral to policymakers in government trying to tackle problems such as working poverty. And yet, estimates of the proportion of working poor in the US vary from 2 to 19 percent. In new research, Brian C. Thiede, Daniel T. Lichter, and Scott R. Sanders seek to explain the variation in statistics around those in working poverty. They write that estimates about the magnitude of working poverty, and on its incidence among racial and ethnic groups can be sensitive to the often technical choices, often based on assumptions about how people get into poverty, made by those who are doing the estimating
Valorisation of lignin – Achievements of the LignoValue project
Lignocellulosic biorefinery for production of biofuels, materials and chemicals requires valorization of all fractions including lignin. As a consequence of its poly-aromatic structure, lignin potentially serves as a source for aromatic chemicals. The developed biorefinery concept of the LignoValue project comprises two major steps: (1) Organosolv fractionation of wheat straw and willow into (hemi)cellulose and high purity lignin. (2) Further conversion of the isolated lignin via catalytic pyrolysis, supercritical depolymerization and partial hydrodeoxygenation (HDO) into different components like low molecular phenolic compounds, wood adhesives and fuel additives. The cellulose fraction resulting after organosolv fractionation is effectively hydrolysed by enzymes for biofuel production. Quality assessment of the liberated lignins shows interesting characteristics for follow-up chemistry such as high purity, relatively low molar mass and polydispersity. Catalytic pyrolysis in a fluidised bed at 400-500°C was found to convert organosolv lignin in 35-55% phenolic oil, 10% identified monomeric phenolic compounds, 10-20% water, 5-20% gas and 35-55% char. Supercritical depolymerisation of lignin in carbon dioxide based solvents resulted in a similar spectrum of products, however, at a lower temperature (ca 300°C) but at higher pressures. In both thermochemical processes the use of promotors or catalysts lead to an improved yield of the target monomeric aromatic products. Also the residual char fraction shows interesting properties for use in bio-char applications. Catalytic semi-continuous HDO of lignin in hydrogen atmosphere can be manipulated to yield both light oils or heavy oils as potential additives to fuels. Suitable catalysts were found to convert depolymerised lignin to phenolic oils in high yields. In this process no char formation is observed. The lignin oils were successfully tested on lab scale as partial substitution of phenol in resins for gluing wood panels. The LignoValue concept is critically reviewed in a techno-economic analysis demonstrating the potential for further commercial development and adoptation of this innovative biorefinery process in Europe
Child health, infant formula funding and South African health professionals: Eliminating conflict of interest
Despite clear evidence of the benefits of exclusive and continued breastfeeding for children, women and society, far too few children in South Africa (SA) are breastfed. One of the major impediments to improving this situation is the continued and aggressive marketing of breastmilk substitutes (BMSs) and infiltration of the BMS industry into contexts with exposure to health professionals. In this article we, as academics, practitioners and child health advocates, describe contraventions of the regulations that protect breastfeeding in SA and argue that bold, proactive leadership to eliminate conflict of interest in respect of the BMS industry is urgently required, together with far greater investments in proven interventions to promote and support breastfeeding
Astrophysical Constraints on Modifying Gravity at Large Distances
Recently, several interesting proposals were made modifying the law of
gravity on large scales, within a sensible relativistic formulation. This
allows a precise formulation of the idea that such a modification might account
for galaxy rotation curves, instead of the usual interpretation of these curves
as evidence for dark matter. We here summarize several observational
constraints which any such modification must satisfy, and which we believe make
more challenging any interpretation of galaxy rotation curves in terms of new
gravitational physics.Comment: References added, submitted to Classical & Quantum Gravit
AzTEC Millimetre Survey of the COSMOS Field - II. Source Count Overdensity and Correlations with Large-Scale Structure
We report an over-density of bright sub-millimetre galaxies (SMGs) in the
0.15 sq. deg. AzTEC/COSMOS survey and a spatial correlation between the SMGs
and the optical-IR galaxy density at z <~ 1.1. This portion of the COSMOS field
shows a ~ 3-sigma over-density of robust SMG detections when compared to a
background, or "blankfield", population model that is consistent with SMG
surveys of fields with no extragalactic bias. The SMG over-density is most
significant in the number of very bright detections (14 sources with measured
fluxes S(1.1mm) > 6 mJy), which is entirely incompatible with sample variance
within our adopted blank-field number densities and infers an over-density
significance of >> 4. We find that the over-density and spatial correlation to
optical-IR galaxy density are most consistent with lensing of a background SMG
population by foreground mass structures along the line of sight, rather than
physical association of the SMGs with the z <~ 1.1 galaxies/clusters. The SMG
positions are only weakly correlated with weak-lensing maps, suggesting that
the dominant sources of correlation are individual galaxies and the more
tenuous structures in the region and not the massive and compact clusters.
These results highlight the important roles cosmic variance and large-scale
structure can play in the study of SMGs.Comment: 12 pages, 11 figures, 2 tables, accepted for publication in MNRA
Deep 1.1 mm-wavelength imaging of the GOODS-S field by AzTEC/ASTE - I. Source catalogue and number counts
[Abridged] We present the first results from a 1.1 mm confusion-limited map
of the GOODS-S field taken with AzTEC on the ASTE telescope. We imaged a 270
sq. arcmin field to a 1\sigma depth of 0.48 - 0.73 mJy/beam, making this one of
the deepest blank-field surveys at mm-wavelengths ever achieved. Although our
GOODS-S map is extremely confused, we demonstrate that our source
identification and number counts analyses are robust, and the techniques
discussed in this paper are relevant for other deeply confused surveys. We find
a total of 41 dusty starburst galaxies with S/N >= 3.5 within this uniformly
covered region, where only two are expected to be false detections. We derive
the 1.1mm number counts from this field using both a "P(d)" analysis and a
semi-Bayesian technique, and find that both methods give consistent results.
Our data are well-fit by a Schechter function model with (S', N(3mJy), \alpha)
= (1.30+0.19 mJy, 160+27 (mJy/deg^2)^(-1), -2.0). Given the depth of this
survey, we put the first tight constraints on the 1.1 mm number counts at
S(1.1mm) = 0.5 mJy, and we find evidence that the faint-end of the number
counts at S(850\mu m) < 2.0 mJy from various SCUBA surveys towards lensing
clusters are biased high. In contrast to the 870 \mu m survey of this field
with the LABOCA camera, we find no apparent under-density of sources compared
to previous surveys at 1.1 mm. Additionally, we find a significant number of
SMGs not identified in the LABOCA catalogue. We find that in contrast to
observations at wavelengths < 500 \mu m, MIPS 24 \mu m sources do not resolve
the total energy density in the cosmic infrared background at 1.1 mm,
demonstrating that a population of z > 3 dust-obscured galaxies that are
unaccounted for at these shorter wavelengths potentially contribute to a large
fraction (~2/3) of the infrared background at 1.1 mm.Comment: 21 pages, 9 figures. Accepted to MNRAS
Resistant Starch and Starch Thermal Characteristics in Exotic Corn Lines Grown in Temperate and Tropical Environments
Corn as a food that is heated and cooled to allow starch retrogradation has higher levels of resistant starch (RS). Increasing the amount of RS can make corn an even healthier food and may be accomplished by breeding and selection, especially by using exotic germplasm. Sixty breeding lines of introgressed exotic germplasm backgrounds, selected for high yield, were grown in three tropical and temperate locations and analyzed for starch thermal characteristics and RS levels. Although actual values for all starch characteristics were within normal levels, most characteristics had significant genotypic effects, and all had significant location effects. Thermal properties of retrograded starch were more influenced by the environment than the thermal properties of raw starch, making retrograded starch traits more heritable than raw starch traits. This suggests that a breeding strategy based on retrograded starch traits will have a better chance of success than a breeding strategy based on raw starch traits. A significant genotype effect for RS levels indicates that genotypic selection to raise the level of RS and increase the healthful aspects of corn food should be successful. Significant location effects indicate that breeders using winter nurseries to accelerate their breeding progress need to be careful when making selections using RS data collected on seed grown in the tropics. A small but highly significant correlation between RS and some thermal characteristics, especially percentage of retrogradation, indicates that we may be able to select promising genotypes for RS selection based on our extensive database of thermal characteristics collected on a wide number of diverse corn lines
AzTEC Millimetre Survey of the COSMOS Field: I. Data Reduction and Source Catalogue
We present a 1.1 mm wavelength imaging survey covering 0.3 sq. deg. in the
COSMOS field. These data, obtained with the AzTEC continuum camera on the James
Clerk Maxwell Telescope (JCMT), were centred on a prominent large-scale
structure over-density which includes a rich X-ray cluster at z = 0.73. A total
of 50 millimetre galaxy candidates, with a significance ranging from 3.5-8.5
sigma, are extracted from the central 0.15 sq. deg. area which has a uniform
sensitivity of 1.3 mJy/beam. Sixteen sources are detected with S/N > 4.5, where
the expected false-detection rate is zero, of which a surprisingly large number
(9) have intrinsic (de-boosted) fluxes > 5 mJy at 1.1 mm. Assuming the emission
is dominated by radiation from dust, heated by a massive population of young,
optically-obscured stars, then these bright AzTEC sources have FIR luminosities
> 6 x 10^12 L(sun) and star formation-rates > 1100 M(sun)/yr. Two of these nine
bright AzTEC sources are found towards the extreme peripheral region of the
X-ray cluster, whilst the remainder are distributed across the larger-scale
over-density. We describe the AzTEC data reduction pipeline, the
source-extraction algorithm, and the characterisation of the source catalogue,
including the completeness, flux de-boosting correction, false-detection rate
and the source positional uncertainty, through an extensive set of Monte-Carlo
simulations. We conclude with a preliminary comparison, via a stacked analysis,
of the overlapping MIPS 24 micron data and radio data with this AzTEC map of
the COSMOS field.Comment: 16 pages, 12 figures, 2 tables, accepted for publication in MNRA
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