1,201 research outputs found
Addressing Undernutrition in Nigeria: What Next?
This briefing sets out the Priorities for Action that emerged from an online discussion amongst experts from central and sub-national government, multilateral and bilateral development agencies, national and international non-governmental organisations, civil society organisations, and research institutions operating in different sectors and levels in Nigeria, and who share the same goal of ending undernutrition in Nigeria. Those advocating within and outside government for commitment and action to address undernutrition in Nigeria are encouraged to adopt and use these Priorities for Action to inform and guide their advocacy efforts
Analysis of ultrasonic transducers with fractal architecture
Ultrasonic transducers composed of a periodic piezoelectric composite are generally accepted as the design of choice in many applications. Their architecture is normally very regular and this is due to manufacturing constraints rather than performance optimisation. Many of these manufacturing restrictions no longer hold due to new production methods such as computer controlled, laser cutting, and so there is now freedom to investigate new types of geometry. In this paper, the plane wave expansion model is utilised to investigate the behaviour of a transducer with a self-similar architecture. The Cantor set is utilised to design a 2-2 conguration, and a 1-3 conguration is investigated with a Sierpinski Carpet geometry
Genetic Control of Immune Response to Pseudorabies and Atrophic Rhinitis Vaccines: II: Comparison of Additive Direct and Maternal Genetic Effects
Data from 52 litters farrowed in two seasons of a cross-fostering experiment were analyzed to estimate variances and covariances for additive direct and maternal genetic effects on immune response to pseudorabies virus and B. bronchiseptica vaccine. Twenty purebred boars and 44 sows of the Duroc, Landrace and Yorkshire breeds were used. Immune response was measured after vaccine challenge. A modified-live pseudorabies (PR) vaccine was administered to piglets at 28 d of age; response was measured by log, serum neutralization titers at 56 d. An inactivated B. bronchiseptica bacterin was administered at 28, 42 and 112 d. Antibody levels were measured relative to positive and negative controls at 28, 56 and 119 d by using an enzyme-linked immunosorbent assay (ELISA). Results from this study for heritability were .18 ± .09 for PR titer and .15 ± .07 and .52 ± .15 for 56- and 119-d ELISA values, respectively. The variability due to nurse environment (maternal genetic variance and common environmental variance) as a percentage of phenotypic variance was 11.1% for PR titers and 29.6 and 8.8% for 56- and 119-d ELISA values, respectively. The heritabilities estimated in this study indicate that, if improved immune response to vaccines is desired, selection may be useful. However, the importance of maternal environment would make early selections less accurate than selections based on immune response measured later in life
Genetic Control of Immune Response to Pseudorabies and Atrophic Rhinitis Vaccines: I. Heterosis, General Combining Ability and Relationship to Growth and Backfat
Data from 988 pigs from 119 litters farrowed in two seasons of a three-breed diallel crossbreeding experiment were analyzed to estimate general combining abilities of breeds and heterosis for humoral immune response to pseudorabies virus and atrophic rhinitis vaccines. Twenty purebred boars and 85 sows of the Duroc, Landrace and Yorkshire breeds were mated to provide the nine breed-of-sire and breed-of-dam combinations. Immune response was measured after vaccination. A modified-live pseudorabies virus (PR) vaccine was administered to piglets at 28 d of age and response measured as log2 serum neutralization titers at 56 d. An inactivated B. bronchiseptica bacterin was administered at 28, 42 and 112 d. Antibody levels were measured relative to positive and negative controls at 28, 56 and 119 d by using an enzyme-linked immunosorbent assay. The results of this study showed that ranking by breed of sire and breed of dam did not differ for general combining ability, and no evidence of significant heterosis for any immune responses was observed. Higher immune response at 56 d to B. bronchiseptica vaccine was associated with lower weaning weight (r = â.09, P\u3c.01). Correlations of days to 100 kg with 56-d and 119-d B. bronchiseptica antibody levels were .15 (P\u3c.01) and .12 (P\u3c.01). The relationship between humoral immune response to PR vaccine and growth traits was similar to that observed for B. bronchiseptica vaccine. Immune response to both antigens was not associated with backfat thickness. Further research using more specifically defined antigens and homogeneous populations of animals is needed to examine nonadditive gene action on the humoral immune response in swine
Smartphone scene generator for efficient characterization of visible imaging detectors
Full characterization of imaging detectors involves subjecting them to
spatially and temporally varying illumination patterns over a large dynamic
range. Here we present a scene generator that fulfills many of these functions.
Based on a modern smartphone, it has a number of good features, including the
ability to generate nearly arbitrary optical scenes, high spatial resolution
(13 um), high dynamic range (~10^4), near-Poisson limited illumination
stability over time periods from 100 ms to many days, and no background noise.
The system does not require any moving parts and may be constructed at modest
cost. We present the optical, mechanical, and software design, test data
validating the performance, and application examples.Comment: 14 pages. This version includes code, available here:
https://github.com/Leo-Nea
Search for Optical Pulsation in M82 X-2
We report on a search for optical pulsation from M82 X-2 over a range of periods. M82 X-2 is an X-ray pulsar with a 1.37s average spin period and a 2.5 day sinusoidal modulation. The observations were done with the ARray Camera for Optical to Near-IR Spectrophotometry at the 200 inch Hale telescope at the Palomar Observatory. We performed H test and Ï^2 statistical analysis. No significant optical pulsations were found in the wavelength range of 3000â11000 Ă
with a pulsation period between 1.36262 and 1.37462 s. We found an upper limit on pulsed emission in the 4000â8000 Ă
wavelength range to be fainter than ~20.5 mag_(AB) , corresponding to ~23 ÎŒJy
Trends in the Statistical Assessment of Reliability
Changes in technology have had and will continue to have a strong effect on changes in the area of statistical assessment of reliability data. These changes include higher levels of integration in electronics, improvements in measurement technology and the deployment of sensors and smart chips into more products, dramatically improved computing power and storage technology, and the development of new, powerful statistical methods for graphics, inference, and experimental design and reliability test planning. This paper traces some of the history of the development of statistical methods for reliability assessment and makes some predictions about the future
Smectic ordering in liquid crystal - aerosil dispersions II. Scaling analysis
Liquid crystals offer many unique opportunities to study various phase
transitions with continuous symmetry in the presence of quenched random
disorder (QRD). The QRD arises from the presence of porous solids in the form
of a random gel network. Experimental and theoretical work support the view
that for fixed (static) inclusions, quasi-long-range smectic order is destroyed
for arbitrarily small volume fractions of the solid. However, the presence of
porous solids indicates that finite-size effects could play some role in
limiting long-range order. In an earlier work, the nematic - smectic-A
transition region of octylcyanobiphenyl (8CB) and silica aerosils was
investigated calorimetrically. A detailed x-ray study of this system is
presented in the preceding Paper I, which indicates that pseudo-critical
scaling behavior is observed. In the present paper, the role of finite-size
scaling and two-scale universality aspects of the 8CB+aerosil system are
presented and the dependence of the QRD strength on the aerosil density is
discussed.Comment: 14 pages, 10 figures, 1 table. Companion paper to "Smectic ordering
in liquid crystal - aerosil dispersions I. X-ray scattering" by R.L. Leheny,
S. Park, R.J. Birgeneau, J.-L. Gallani, C.W. Garland, and G.S. Iannacchion
Drag on particles in a nematic suspension by a moving nematic-isotropic interface
We report the first clear demonstration of drag on colloidal particles by a moving nematic-isotropic
interface. The balance of forces explains our observation of periodic, strip-like structures that are produced by the movement of these particles
Associations between mixtures of urinary phthalate metabolites with gestational age at delivery: a time to event analysis using summative phthalate risk scores
Abstract
Background
Preterm birth is a significant public health concern and exposure to phthalates has been shown to be associated with an increased odds of preterm birth. Even modest reductions in gestational age at delivery could entail morbid consequences for the neonate and analyzing data with this additional information may be useful. In the present analysis, we consider gestational age at delivery as our outcome of interest and examine associations with multiple phthalates.
Methods
Women were recruited early in pregnancy as part of a prospective, longitudinal birth cohort at the Brigham and Womenâs Hospital in Boston, Massachusetts. Urine samples were collected at up to four time points during gestation for urinary phthalate metabolite measurement, and birth outcomes were recorded at delivery. From this population, we selected all 130 cases of preterm birth (<â37Â weeks of gestation) as well as 352 random controls. We conducted analysis with both geometric average of the exposure concentrations across the first three visits as well as using repeated measures of the exposure. Two different time to event models were used to examine associations between nine urinary phthalate metabolite concentrations and time to delivery. Two different approaches to constructing a summative phthalate risk score were also considered.
Results
The single-pollutant analysis using a Cox proportional hazards model showed the strongest association with a hazard ratio (HR) of 1.21 (95% confidence interval (CI): 1.09, 1.33) per interquartile range (IQR) change in average log-transformed mono-2-ethyl-5-carboxypentyl phthalate (MECPP) concentration. Using the accelerated failure time model, we observed a 1.19% (95% CI: 0.26, 2.11%) decrease in gestational age in association with an IQR change in average log-transformed MECPP. We next examined associations with an environmental risk score (ERS). The fourth quartile of ERS was significantly associated with a HR of 1.44 (95% CI: 1.19, 1.75) and a reduction of 2.55% (95% CI: 0.76, 4.30%) in time to delivery (in days) compared to the first quartile.
Conclusions
On average, pregnant women with higher urinary metabolite concentrations of individual phthalates have shorter time to delivery. The strength of the observed associations are amplified with the risk scores when compared to individual pollutants.https://deepblue.lib.umich.edu/bitstream/2027.42/144517/1/12940_2018_Article_400.pd
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