10,239 research outputs found
Federal child nutrition programs are important to rural households
This brief, based on data from the U.S. Census Bureau, examines how rural families use four of the major federal child nutrition programs. It finds that 29 percent of rural families with children participate but that there are barriers to these nutrition programs, such as the lack of public transportation and high operating costs for rural schools and child care programs
Mixture of easy trials enables transient and sustained perceptual improvements through priming and perceptual learning.
The sense of vision allows us to discriminate fine details across a wide range of tasks. How to improve this perceptual skill, particularly within a short training session, is of substantial interest. Emerging evidence suggests that mixing easy trials can quickly improve performance in hard trials, but it is equivocal whether the improvement is short-lived or long-lasting, and additionally what accounts for this improvement. Here, by tracking objective performance (accuracy) and subjective experience (ratings of target visibility and choice confidence) over time and in a large sample of participants, we demonstrate the coexistence of transient and sustained effects of mixing easy trials, which differ markedly in their timescales, in their effects on subjective awareness, and in individual differences. In particular, whereas the transient effect was found to be ubiquitous and manifested similarly across objective and subjective measures, the sustained effect was limited to a subset of participants with weak convergence from objective and subjective measures. These results indicate that mixture of easy trials enables two distinct, co-existing forms of rapid perceptual improvements in hard trials, as mediated by robust priming and fragile learning. Placing constraints on theory of brain plasticity, this finding may also have implications for alleviating visual deficits
Smoking related disease risk, area deprivation and health behaviours
Acknowledgements We thank Professor Luke Vale, Dr Diane Stockton and participants at the Faculty of Public Health conference, Aviemore, Scotland, November 2011 and UK Society for Behavioural Medicine conference, Stirling, Scotland, December 2011 for helpful comments. Funding This work was supported by the Medical Research Council National Preventive Research Initiative Phase 2 [G0701874]; see http://www.npri.org.uk. The Funding Partners relevant to this award are: British Heart Foundation; Cancer Research UK; Department of Health; Diabetes UK; Economic and Social Research Council; Medical Research Council; Research and Development Office for the Northern Ireland Health and Social Services; Chief Scientist Office; Scottish Government Health Directorates; The Stroke Association; Welsh Assembly Government and World Cancer Research Fund. The Health Economics Research Unit is funded by the Chief Scientist Office of the Scottish Government Health and Social Care DirectoratePeer reviewedPostprin
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Assessing the detailed time course of perceptual sensitivity change in perceptual learning.
The learning curve in perceptual learning is typically sampled in blocks of trials, which could result in imprecise and possibly biased estimates, especially when learning is rapid. Recently, Zhao, Lesmes, and Lu (2017, 2019) developed a Bayesian adaptive quick Change Detection (qCD) method to accurately, precisely, and efficiently assess the time course of perceptual sensitivity change. In this study, we implemented and tested the qCD method in assessing the learning curve in a four-alternative forced-choice global motion direction identification task in both simulations and a psychophysical experiment. The stimulus intensity in each trial was determined by the qCD, staircase or random stimulus selection (RSS) methods. Simulations showed that the accuracy (bias) and precision (standard deviation or confidence bounds) of the estimated learning curves from the qCD were much better than those obtained by the staircase and RSS method; this is true for both trial-by-trial and post hoc segment-by-segment qCD analyses. In the psychophysical experiment, the average half widths of the 68.2% credible interval of the estimated thresholds from the trial-by-trial and post hoc segment-by-segment qCD analyses were both quite small. Additionally, the overall estimates from the qCD and staircase methods matched extremely well in this task where the behavioral rate of learning is relatively slow. Our results suggest that the qCD method can precisely and accurately assess the trial-by-trial time course of perceptual learning
Effects of vegetation, fire and other disturbance factors on small mammal ecology and conservation
The relationship of vegetation and disturbance factors to the distribution, abundance and diversity of small mammals in the eastern Otway region, Victoria were investigated. Antechinus stuartii, Rattus fuscipes and Rattus lutreolus were widely distributed and occurred in the majority of the eleven floristic vegetation groups identified. Antechinus minimus, Antechinus swainsonnii and Pseudomys novaehollandiae had restricted distributions and were recorded in only two or three vegetation groups. New information on the distribution of the rare species P. novaehollandiae, was obtained and two floristically rich vegetation groups that it preferred were identified. Species-rich small mammal communities occurred in vegetation communities with high numbers of sclerophyll plant species and high structural diversity. Maximum food resources were considered to be provided in these communities. Local habitat diversity was also correlated with species-richness. Small mammal abundance was maximum in non-sclerophyllous canmunities, where high plant productivity was considered to be important. For the first time, the presence of the plant pathogen Phytophthora cinnamomi was shown to affect small mammals. It was associated with small mammal communities of low species richness and abundance, Recovery of small mammal populations after wildfire was slow until the fourth year. Mus musculus reached peak abundance from 2-3 years and then declined rapidly. P. novaehollandiae was the only native species that achieved maximum abundance early in the succession. A. stuartii, R. fuscipes and R. lutreolus approached maximum abundance in mid-succession, while Isoodon obesulus was a mid- to late-successional species. A. minimus survived the fire, but did not persist after one year. The pattern of succession was influenced by attributes of species, such as survival after fire, their ability to disperse and reproduce
The small bowel and functional dyspepsia - peptide hormones and neurotransmitters
Functional dyspepsia (FD) is believed to be caused by pathophysiological changes in
the upper gut. Gastro-intestinal motility, epithelial transport and signalling is associated
with the metabolism of nutrients and the complex regulation of hunger and satiety.
Glucagon-like peptide 1 (GLP-1) and peptide YY (PYY) are considered āhot targetsā.
Both are anorexigenic, can induce nausea, and are involved in neuronal and hormonal
feedback. Epithelial transport and signalling are partly controlled by the action of the
neurotransmitter serotonin (5-HT). 5-HT forms the ālinkā between luminal stimulation
and the enteric nervous system. We aimed at investigating if GLP-1, PYY and 5-HT
are involved in the pathogenesis of FD.
In study I and II healthy subjects were given a radiolabelled omelette during
intravenous infusion of saline, PYY1-36, or PYY3-36 (study I) and saline or the GLP-
1 receptor antagonist Exendin(9-39)amide (study II) in a single-blinded, randomized
design. Gastric emptying (scintigraphy), appetite ratings (VAS), and plasma
concentrations of insulin, glucose, GLP-1, PYY and glucagon were studied. In study
III FD patients and controls consumed two liquid meals, first a fixed amount and then
until maximal satiety. Gastric emptying (paracetamol absorption test) and plasma
concentrations of GLP-1, glucose and insulin were assessed as well as appetite ratings
and dyspeptic symptoms. In study IV duodenal mucosal biopsies from FD patients and
controls were studied for the number of 5-HT-containing cells (immunohistochemistry)
and the expression of different 5-HT receptors by means of PCR. Biopsies were also
mounted in Ussing chambers for evaluation of basal and 5-HT-stimulated short-circuit
current. In study V duodenal biopsies from non-patients with FD and controls from a
population based upper endoscopy study were evaluated immunohistochemically for
Chromogranin A (CGA) as endocrine cell marker and 5-HT. Individuals with FD were
further divided into epigastric pain syndrome (EPS) and postprandial distress syndrome
(PDS).
PYY3-36 and PYY1-36 inhibits gastric emptying (PYY3-36 most effectively), and
decreased the postprandial rise in insulin. PYY3-36 induced nausea and decreased
prospective consumption. GLP-1 was involved in regulation of postprandial gastric
motility, in insulin and glucose levels, and restrained glucagon secretion. Gastric
emptying was not affected and we conclude that GLP-1 has a role as incretin hormone
independent of gastric emptying. FD patients had normal postprandial glucose and
GLP-1 concentrations. The FD-EPS subgroup had higher postprandial insulin levels
compared to controls. Exogenous 5-HT induced lower short-circuit current and higher
electrical resistance in FD. FD patients had higher gene expression of HTR3E and
SERT and lower expression of HTR7 and TPH1. The number of 5-HT containing cells
in duodenal mucosa was similar in FD patients and controls, and adults with FD had
less endocrine cells and a normal number of 5-HT containing cells compared to
controls. Endocrine cells was significantly decreased in the duodenal bulb in EPS but
not PDS.
Our results provide new evidence that altered endocrine secretion in the small bowel is
part of the disease mechanism in FD, with PYY and GLP-1 as key candidates. GLP-1
specifically contributes to the development of nausea. Furthermore, FD patients have
abnormal 5-HT stimulated electrolyte secretion in the duodenum with possible
involvement of the 5-HT receptors 3E and 7
Characterization Of Invariant Membrane Proteins Of Trypanosoma (duttonella) Vivax
Monoclonal antibodies (mAbs), raised against whole, fixed, uncoated, culture forms of Trypanosoma (Duttonella) vivax, were used to identify two invariant membrane proteins of this protozoan parasite. Since non-variant membrane proteins of the cell surface, flagellar pocket and endocytic pathway are potential targets for the control of trypanosomiasis of livestock by immunization, the identification and characterization of invariant membrane proteins is a necessary preliminary step.;A 65 kDA invariant membrane glycoprotein (gp65), identified using mAb 4E1, was the main focus of this study. Immunolocalization studies using the monoclonal antibody (mAb 4E1) for immunofluorescence staining and immunoelectron microscopy, demonstrated that the 65 kDa antigen was associated with tubulo-vesicular profiles in the posterior region of the bloodstream form parasite. Endocytosis and co-localization experiments revealed that gp65 was associated with an endocytic compartment of T. vivax which is morphologically and temporally similar to the endosomal system of mammalian cells. Double labelling experiments using the mAb and a polyclonal anti-variant surface glycoprotein antibody (R{dollar}{lcub}\alpha{rcub}{dollar}VSG) to simultaneously localize both gp65 and intracellular VSG, demonstrated that there was little overlap in the distribution of these antigens. Thus, gp65 is associated with tubules and vesicles that are involved in endocytosis but which appear to be distinct from VSG processing pathways in the cell.;A 35 kDa T. vivax antigen was shown in immunolocalization studies to be associated primarily with the surface of bloodstream forms of the parasite. Although T. vivax 3{dollar}\sp{lcub}\prime{rcub}{dollar}-nucleotidase activity, a surface membrane enzyme in other trypanosomatids, migrated at 35 kDa on SDS-PAGE gels, it is doubtful that the 35 kDa antigen identified with the monoclonal antibody (mAb 4B11) is specific for the T. vivax 3{dollar}\sp\prime{dollar}-nucleotidase since the two proteins exhibited different capacities to bind to immobilized Concanavalin A.;Both T. vivax invariant antigens have potential as targets for disease control based on their location in the cell and thus merit further study to this end. In addition, gp65 is the first putative marker for an endosomal compartment of trypanosomes and has potential for use in the further study of endocytosis in African trypanosomes, a process upon which these parasites are dependent upon for survival
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