2,349 research outputs found
Multilevel correlates of household anthropometric typologies in Colombian mothers and their infants
Background. The aim of this study was to establish the association of maternal, family, and contextual correlates of anthropometric typologies at the household level in Colombia using 2005 Demographic Health Survey (DHS/ENDS) data.Methods. Household-level information from mothers 18-49 years old and their children less than 5 years old was included. Stunting and overweight were assessed for each child. Mothers were classified according to their body mass index. Four anthropometric typologies at the household level were constructed: normal, underweight, overweight, and dual burden. Four three-level [households (n = 8598) nested within municipalities (n = 226), nested within states (n = 32)] hierarchical polytomous logistic models were developed. Household log-odds of belonging to one of the four anthropometric categories, holding 'normal' as the reference group, were obtained.Results. This study found that anthropometric typologies were associated with maternal and family characteristics of maternal age, parity, maternal education, and wealth index. Higher municipal living conditions index was associated with a lower likelihood of underweight typology and a higher likelihood of overweight typology. Higher population density was associated with a lower likelihood of overweight typology.Conclusion. Distal and proximal determinants of the various anthropometric typologies at the household level should be taken into account when framing policies and designing interventions to reduce malnutrition in Colombia. Copyright © The Author(s) 2018
Multilevel correlates of household anthropometric typologies in Colombian mothers and their infants
Background. The aim of this study was to establish the association of maternal, family, and contextual correlates of anthropometric typologies at the household level in Colombia using 2005 Demographic Health Survey (DHS/ENDS) data.Methods. Household-level information from mothers 18-49 years old and their children less than 5 years old was included. Stunting and overweight were assessed for each child. Mothers were classified according to their body mass index. Four anthropometric typologies at the household level were constructed: normal, underweight, overweight, and dual burden. Four three-level [households (n = 8598) nested within municipalities (n = 226), nested within states (n = 32)] hierarchical polytomous logistic models were developed. Household log-odds of belonging to one of the four anthropometric categories, holding 'normal' as the reference group, were obtained.Results. This study found that anthropometric typologies were associated with maternal and family characteristics of maternal age, parity, maternal education, and wealth index. Higher municipal living conditions index was associated with a lower likelihood of underweight typology and a higher likelihood of overweight typology. Higher population density was associated with a lower likelihood of overweight typology.Conclusion. Distal and proximal determinants of the various anthropometric typologies at the household level should be taken into account when framing policies and designing interventions to reduce malnutrition in Colombia. Copyright © The Author(s) 2018
"Cold Melting" of Invar Alloys
An anomalously strong volume magnetostriction in Invars may lead to a
situation when at low temperatures the dislocation free energy becomes negative
and a multiple generation of dislocations becomes possible. This generation
induces a first order phase transition from the FCC crystalline to an amorphous
state, and may be called "cold melting". The possibility of the cold melting in
Invars is connected with the fact that the exchange energy contribution into
the dislocation self energy in Invars is strongly enhanced, as compared to
conventional ferromagnetics, due to anomalously strong volume magnetostriction.
The possible candidate, where this effect can be observed, is a FePt disordered
Invar alloy in which the volume magnetostriction is especially large
Parton Distributions Working Group
The main focus of this working group was to investigate the different issues
associated with the development of quantitative tools to estimate parton
distribution functions uncertainties. In the conclusion, we introduce a
"Manifesto" that describes an optimal method for reporting data.Comment: Report of the Parton Distributions Working Group of the 'QCD and Weak
Boson Physics workshop in preparation for Run II at the Fermilab Tevatron'.
Co-Conveners: L. de Barbaro, S.A. Keller, S. Kuhlmann, H. Schellman, and
W.-K. Tun
Determination of the Jet Energy Scale at the Collider Detector at Fermilab
A precise determination of the energy scale of jets at the Collider Detector
at Fermilab at the Tevatron collider is described. Jets are used in
many analyses to estimate the energies of partons resulting from the underlying
physics process. Several correction factors are developed to estimate the
original parton energy from the observed jet energy in the calorimeter. The jet
energy response is compared between data and Monte Carlo simulation for various
physics processes, and systematic uncertainties on the jet energy scale are
determined. For jets with transverse momenta above 50 GeV the jet energy scale
is determined with a 3% systematic uncertainty
COSMOGRAIL XVI: Time delays for the quadruply imaged quasar DES J0408-5354 with high-cadence photometric monitoring
We present time-delay measurements for the new quadruply imaged quasar DES
J0408-5354, the first quadruply imaged quasar found in the Dark Energy Survey
(DES). Our result is made possible by implementing a new observational strategy
using almost daily observations with the MPIA 2.2m telescope at La Silla
observatory and deep exposures reaching a signal-to-noise ratio of about 1000
per quasar image. This data quality allows us to catch small photometric
variations (a few mmag rms) of the quasar, acting on temporal scales much
shorter than microlensing, hence making the time delay measurement very robust
against microlensing. In only 7 months we measure very accurately one of the
time delays in DES J0408-5354: Dt(AB) = -112.1 +- 2.1 days (1.8%) using only
the MPIA 2.2m data. In combination with data taken with the 1.2m Euler Swiss
telescope, we also measure two delays involving the D component of the system
Dt(AD) = -155.5 +- 12.8 days (8.2%) and Dt(BD) = -42.4 +- 17.6 days (41%),
where all the error bars include systematics. Turning these time delays into
cosmological constraints will require deep HST imaging or ground-based Adaptive
Optics (AO), and information on the velocity field of the lensing galaxy.Comment: 9 pages, 5 figures, accepted for publication in Astronomy &
Astrophysic
Forward Global Photometric Calibration of the Dark Energy Survey
Many scientific goals for the Dark Energy Survey (DES) require calibration of
optical/NIR broadband photometry that is stable in time and uniform
over the celestial sky to one percent or better. It is also necessary to limit
to similar accuracy systematic uncertainty in the calibrated broadband
magnitudes due to uncertainty in the spectrum of the source. Here we present a
"Forward Global Calibration Method (FGCM)" for photometric calibration of the
DES, and we present results of its application to the first three years of the
survey (Y3A1). The FGCM combines data taken with auxiliary instrumentation at
the observatory with data from the broad-band survey imaging itself and models
of the instrument and atmosphere to estimate the spatial- and time-dependence
of the passbands of individual DES survey exposures. "Standard" passbands are
chosen that are typical of the passbands encountered during the survey. The
passband of any individual observation is combined with an estimate of the
source spectral shape to yield a magnitude in the standard
system. This "chromatic correction" to the standard system is necessary to
achieve sub-percent calibrations. The FGCM achieves reproducible and stable
photometric calibration of standard magnitudes of stellar
sources over the multi-year Y3A1 data sample with residual random calibration
errors of per exposure. The accuracy of the
calibration is uniform across the DES footprint to
within . The systematic uncertainties of magnitudes in
the standard system due to the spectra of sources are less than
for main sequence stars with .Comment: 25 pages, submitted to A
Contribution of noncanonical antigens to virulence and adaptive immunity in human infection with enterotoxigenic E. coli
Enterotoxigenic Escherichia coli (ETEC) contributes significantly to the substantial burden of infectious diarrhea among children living in low- and middle-income countries. In the absence of a vaccine for ETEC, children succumb to acute dehydration as well as nondiarrheal sequelae related to these infections, including malnutrition. The considerable diversity of ETEC genomes has complicated canonical vaccine development approaches defined by a subset of ETEC pathovar-specific antigens known as colonization factors (CFs). To identify additional conserved immunogens unique to this pathovar, we employed an “open-aperture” approach to capture all potential conserved ETEC surface antigens, in which we mined the genomic sequences of 89 ETEC isolates, bioinformatically selected potential surface-exposed pathovar-specific antigens conserved in more than 40% of the genomes (n = 118), and assembled the representative proteins onto microarrays, complemented with known or putative colonization factor subunit molecules (n = 52) and toxin subunits. These arrays were then used to interrogate samples from individuals with acute symptomatic ETEC infections. Surprisingly, in this approach, we found that immune responses were largely constrained to a small number of antigens, including individual colonization factor antigens and EtpA, an extracellular adhesin. In a Bangladeshi cohort of naturally infected children <2 years of age, both EtpA and a second antigen, EatA, elicited significant serologic responses that were associated with protection from symptomatic illness. In addition, children infected with ETEC isolates bearing either etpA or eatA genes were significantly more likely to develop symptomatic disease. These studies support a role for antigens not presently targeted by vaccines (noncanonical) in virulence and the development of adaptive immune responses during ETEC infections. These findings may inform vaccine design efforts to complement existing approaches
- …