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Household demand persistence for child micronutrient supplementation.
Addressing early-life micronutrient deficiencies can improve short- and long-term outcomes. In most contexts, private supply chains will be key to effective and efficient preventative supplementation. With established vendors, we conducted a 60-week market trial for a food-based micronutrient supplement in rural Burkina Faso with randomized price and non-price treatments. Repeat purchases - critical for effective supplementation - are extremely price sensitive. Loyalty cards boost demand more than price discounts, particularly in non-poor households where the father is the cardholder. A small minority of households achieved sufficient supplementation for their children through purely retail distribution, suggesting the need for more creative public-private delivery platforms informed by insights into household demand persistence and heterogeneity
Integrating Economic Analysis with a Randomized Controlled Trial: Willingness-to-Pay for a New Maternal Nutrient Supplement
Maternal nutrition during pregnancy can have significant implications for a child’s prenatal growth and development, and undernutrition experienced during the prenatal period increases the risk of early childhood morbidity and mortality and can permanently impair a child’s physical growth and cognitive development. We use new data from Ghana generated using contingent valuation and experimental auction techniques to estimate willingness-to-pay (WTP) for LNS, a new nutrient supplement aimed at preventing maternal undernutrition during pregnancy. We also explore the relative importance of individual and household characteristics as well as information about the long-term benefits of preventing undernutrition on WTP. We find that WTP is positive for a large majority of individuals in our samples, and the level of WTP varies significantly with individual and household characteristics including gender, household food insecurity, and household expenditures. These findings suggest important policy implications for the development of delivery options and pricing mechanisms for LNS.Economic Development, Nutrition, Willingness-to-Pay, Food Consumption/Nutrition/Food Safety, Health Economics and Policy, International Development,
Detection of an Optical Counterpart to the ALFALFA Ultra-compact High Velocity Cloud AGC 249525
We report on the detection at 98% confidence of an optical counterpart to
AGC 249525, an Ultra-Compact High Velocity Cloud (UCHVC) discovered by the
ALFALFA blind neutral hydrogen survey. UCHVCs are compact, isolated HI clouds
with properties consistent with their being nearby low-mass galaxies, but
without identified counterparts in extant optical surveys. Analysis of the
resolved stellar sources in deep - and -band imaging from the WIYN pODI
camera reveals a clustering of possible Red Giant Branch stars associated with
AGC 249525 at a distance of 1.640.45 Mpc. Matching our optical detection
with the HI synthesis map of AGC 249525 from Adams et al. (2016) shows that the
stellar overdensity is exactly coincident with the highest-density HI contour
from that study. Combining our optical photometry and the HI properties of this
object yields an absolute magnitude of , a stellar
mass between and , and an HI to stellar mass ratio between 9 and 144. This object has
stellar properties within the observed range of gas-poor Ultra-Faint Dwarfs in
the Local Group, but is gas-dominated.Comment: 9 pages, 4 figures; accepted to ApJ
Constraints on the Intergalactic Transport of Cosmic Rays
Motivated by recent experimental proposals to search for extragalactic cosmic
rays (including anti-matter from distant galaxies), we study particle
propagation through the intergalactic medium (IGM). We first use estimates of
the magnetic field strength between galaxies to constrain the mean free path
for diffusion of particles through the IGM. We then develop a simple analytic
model to describe the diffusion of cosmic rays. Given the current age of
galaxies, our results indicate that, in reasonable models, a completely
negligible number of particles can enter our Galaxy from distances greater than
Mpc for relatively low energies ( GeV/n). We also find
that particle destruction in galaxies along the diffusion path produces an
exponential suppression of the possible flux of extragalactic cosmic rays.
Finally, we use gamma ray constraints to argue that the distance to any
hypothetical domains of anti-matter must be roughly comparable to the horizon
scale.Comment: 24 pages, AAS LaTex, 1 figure, accepted to Ap
Model fit versus biological relevance: evaluating photosynthesis-temperature models for three tropical seagrass species
When several models can describe a biological process, the equation that best fits the data is typically
considered the best. However, models are most useful when they also possess biologically-meaningful
parameters. In particular, model parameters should be stable, physically interpretable, and transferable
to other contexts, e.g. for direct indication of system state, or usage in other model types. As an
example of implementing these recommended requirements for model parameters, we evaluated
twelve published empirical models for temperature-dependent tropical seagrass photosynthesis,
based on two criteria: (1) goodness of fit, and (2) how easily biologically-meaningful parameters can
be obtained. All models were formulated in terms of parameters characterising the thermal optimum
(Topt) for maximum photosynthetic rate (Pmax). These parameters indicate the upper thermal limits
of seagrass photosynthetic capacity, and hence can be used to assess the vulnerability of seagrass
to temperature change. Our study exemplifies an approach to model selection which optimises the
usefulness of empirical models for both modellers and ecologists alike
The ALFALFA "Almost Darks" Campaign: Pilot VLA HI Observations of Five High Mass-to-Light Ratio Systems
We present VLA HI spectral line imaging of 5 sources discovered by ALFALFA.
These targets are drawn from a larger sample of systems that were not uniquely
identified with optical counterparts during ALFALFA processing, and as such
have unusually high HI mass to light ratios. These candidate "Almost Dark"
objects fall into 4 categories: 1) objects with nearby HI neighbors that are
likely of tidal origin; 2) objects that appear to be part of a system of
multiple HI sources, but which may not be tidal in origin; 3) objects isolated
from nearby ALFALFA HI detections, but located near a gas-poor early-type
galaxy; 4) apparently isolated sources, with no object of coincident redshift
within ~400 kpc. Roughly 75% of the 200 objects without identified counterparts
in the .40 database (Haynes et al. 2011) fall into category 1. This
pilot sample contains the first five sources observed as part of a larger
effort to characterize HI sources with no readily identifiable optical
counterpart at single dish resolution. These objects span a range of HI mass
[7.41 < log(M) < 9.51] and HI mass to B-band luminosity ratios (3 <
M/L < 9). We compare the HI total intensity and velocity
fields to SDSS optical imaging and to archival GALEX UV imaging. Four of the
sources with uncertain or no optical counterpart in the ALFALFA data are
identified with low surface brightness optical counterparts in SDSS imaging
when compared with VLA HI intensity maps, and appear to be galaxies with clear
signs of ordered rotation. One source (AGC 208602) is likely tidal in nature.
We find no "dark galaxies" in this limited sample. The present observations
reveal complex sources with suppressed star formation, highlighting both the
observational difficulties and the necessity of synthesis follow-up
observations to understand these extreme objects. (abridged)Comment: Astronomical Journal, in pres
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