4,470 research outputs found
Brain Phosphorus Magnetic Resonance Spectroscopy Imaging of Sleep Homeostasis and Restoration in Drug Dependence
Numerous reports have documented a high occurrence of sleep difficulties in drug-dependent populations, prompting researchers to characterize sleep profiles and physiology in drug abusing populations. This mini-review examines studies indicating that drug-dependent populations exhibit alterations in sleep homeostatic and restoration processes in response to sleep deprivation. Sleep deprivation is a principal sleep research tool that results in marked physiological challenge, which provides a means to examine sleep homeostatic processes in response to extended wakefulness. A report from our laboratory demonstrated that following recovery sleep from sleep deprivation, brain high-energy phosphates particularly beta–nucleoside triphosphate (beta-NTP) are markedly increased as measured with phosphorus magnetic resonance spectroscopy (MRS). A more recent study examined the effects of sleep deprivation in opiate-dependent methadone-maintained (MM) subjects. The study demonstrated increases in brain beta-NTP following recovery sleep. Interestingly, these increases were of a markedly greater magnitude in MM subjects compared to control subjects. A similar study examined sleep deprivation in cocaine-dependent subjects demonstrating that cocaine-dependent subjects exhibit greater increases in brain beta-NTP following recovery sleep when compared to control subjects. The studies suggest that sleep deprivation in both MM subjects and cocaine-dependent subjects is characterized by greater changes in brain ATP levels than control subjects. Greater enhancements in brain ATP following recovery sleep may reflect a greater disruption to or impact of sleep deprivation in drug dependent subjects, whereby sleep restoration processes may be unable to properly regulate brain ATP and maintain brain high-energy equilibrium. These studies support the notion of a greater susceptibility to sleep loss in drug dependent populations. Additional sleep studies in drug abusing populations are needed, particularly those that examine potential differential effects of sleep deprivation
Effect of Order of Drug Administration and Repeat Placebos on the Galvanic Skin Resistance in Human Subjects
Evaluation of Dried Distillers Grains with Solubles as a Feedstuff for Heifers in the Last Trimester fo Gestation
Ninety-six crossbred heifers were used in an experiment to evaluate the effect of dried distillers grains plus solubles (DDGS), fed in the last trimester of gestation, on heifer performance and reproduction. Animals were blocked by previous heifer development strategy (Antelope Research Station range developed = ANT 1; Antelope Research Station dry lot developed = ANT 2; Cottonwood research station = CTW), stratified by expected calving date, body weight and body condition score, and randomly allotted to one of twelve pens. Each pen was randomly assigned to one of two treatments (6 pens/treatment; 4 pens per block). Treatments were 1) dried distillers grains and grass hay (DDGS) or 2) soybean hulls and grass hay (SBH). Treatments were applied during the last-trimester of gestation. Diets were developed utilizing the 1996 NRC computer model and designed to meet nutrient requirements at 240 days of gestation under thermo-neutral conditions. Treatment diets offered similar amounts of NEm each day based on assumptions of the energy content of SBH and DDGS (assumed SBH = 80% TDN and DDGS = 88% TDN). Heifers fed the DDGS had a greater (P\u3c0.01) increase in body weight and a heavier (P=0.03) final weight compared to the heifers fed SBH. Body condition score was not affected by diet. Calf birth weights were similar for both the DDGS and SBH treatments with a mean birth weight of 87.0 lbs ± 5.3lb and 85.0 lbs ± 3.4lbs respectively. Treatment had no effect on calving ease or calf vigor scores. These results suggest that in limit fed situations DDGS and SBH can both be supplemented at 40 percent of the diet with no negative affects on cow performance, calf birth weight, or calving difficulty
ASPM and the Evolution of Cerebral Cortical Size in a Community of New World Monkeys
The ASPM (abnormal spindle-like microcephaly associated) gene has been proposed as a major determinant of cerebral cortical size among primates, including humans. Yet the specific functions of ASPM and its connection to human intelligence remain controversial. This debate is limited in part by a taxonomic focus on Old World monkeys and apes. Here we expand the comparative context of ASPM sequence analyses with a study of New World monkeys, a radiation of primates in which enlarged brain size has evolved in parallel in spider monkeys (genus Ateles) and capuchins (genus Cebus). The primate community of Costa Rica is perhaps a model system because it allows for independent pairwise comparisons of smaller- and larger-brained species within two taxonomic families. Accordingly, we analyzed the complete sequence of exon 18 of ASPM in Ateles geoffroyi, Alouatta palliata, Cebus capucinus, and Saimiri oerstedii. As the analysis of multiple species in a genus improves phylogenetic reconstruction, we also analyzed eleven published sequences from other New World monkeys. Our exon-wide, lineage-specific analysis of eleven genera and the ratio of rates of nonsynonymous to synonymous substitutions (dN/dS) on ASPM revealed no detectable evidence for positive selection in the lineages leading toAteles or Cebus, as indicated by dN/dS ratios of ,1.0 (0.6502 and 0.4268, respectively). Our results suggest that a multitude of interacting genes have driven the evolution of larger brains among primates, with different genes involved in this process in different encephalized lineages, or at least with evidence for positive selection not readily apparent for the same genes in all lineages. The primate community of Costa Rica may serve as a model system for future studies that aim to elucidate the molecular mechanisms underlying cognitive capacity and cortical size
Patterns of Recent Natural Selection on Genetic Loci Associated with Sexually Differentiated Human Body Size and Shape Phenotypes
Levels of sex differences for human body size and shape phenotypes are hypothesized to have adaptively reduced following the agricultural transition as part of an evolutionary response to relatively more equal divisions of labor and new technology adoption. In this study, we tested this hypothesis by studying genetic variants associated with five sexually differentiated human phenotypes: height, body mass, hip circumference, body fat percentage, and waist circumference. We first analyzed genome-wide association (GWAS) results for UK Biobank individuals (~194,000 females and ~167,000 males) to identify a total of 114,199 single nucleotide polymorphisms (SNPs) significantly associated with at least one of the studied phenotypes in females, males, or both sexes (P \u3c 5x10-8). From these loci we then identified 3,016 SNPs (2.6%) with significant differences in the strength of association between the female- and male-specific GWAS results at a low false-discovery rate (FDR \u3c 0.001). Genes with known roles in sexual differentiation are significantly enriched for co-localization with one or more of these SNPs versus SNPs associated with the phenotypes generally but not with sex differences (2.73-fold enrichment; permutation test; P = 0.0041). We also confirmed that the identified variants are disproportionately associated with greater phenotype effect sizes in the sex with the stronger association value. We then used the singleton density score statistic, which quantifies recent (within the last ~3,000 years; post-agriculture adoption in Britain) changes in the frequencies of alleles underlying polygenic traits, to identify a signature of recent positive selection on alleles associated with greater body fat percentage in females (permutation test; P = 0.0038; FDR = 0.0380), directionally opposite to that predicted by the sex differences reduction hypothesis. Otherwise, we found no evidence of positive selection for sex difference-associated alleles for any other trait. Overall, our results challenge the longstanding hypothesis that sex differences adaptively decreased following subsistence transitions from hunting and gathering to agriculture
Tailoring non-stoichiometry and mixed ionic-electronic conductivity in nanostructured Pr-substituted ceria
High concentrations of mobile oxygen vacancies are crucial for devices such as SOFCs, SOECs, gas permeation membranes, and sensors, while for other applications such as ferroelectrics and piezoelectrics, oxygen vacancies are detrimental. Hence there is great interest in tailoring the oxygen vacancy concentration and mobility for given materials. Changes in oxygen non-stoichiometry also result in dilation of the crystal lattice, known as chemical expansion, and therefore there is a coupling between the electrical, chemical, and mechanical properties known as electro-chemo-mechanical coupling. Confined systems, such as thin films, are being investigated as a way to tailor the non-stoichiometry and transport properties of materials, shifting the paradigm away from searching for new materials or compositions.
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Evaluation of Performance and Costs of Two Heifer Development Systems
Early weaned (EW) heifers must be developed for a longer period of time usually resulting in increased development costs. Developing EW heifers on native range may reduce these costs. Dried distillers grains plus solubles (DDGS) offers protein and energy that compliment native forages for developing heifers. The objective of this study was to evaluate the performance and costs of two heifer development systems in northwest South Dakota. Sixty-five nulliparous crossbred beef heifers were randomly allotted to one of two systems: 1) heifers (n=33) weaned at 132 d of age (461 lb) and developed on range with a DDGS supplement (1.8 to 6.4 lb/hd/d) from Sept. 25 to May 18 (Range); 2) heifers (n=32) weaned at 218 days of age (605 lb) and developed in a drylot with grass hay and a conventional supplement (2.6 to 3.6 lb/hd/d) from Dec. 2 to May 18 (Normal). Supplement levels were established to result in both groups of heifers reaching 65% of mature weight at breeding (863 lb). All heifers were managed similarly after May 18. Heifers were synchronized with a shot of PGF2α and bred natural service beginning June 14. As necessary for target weights to be reached, ADG through the feeding period was greater (P \u3c 0.05) for Range (1.68 lb/d) than (Normal 1.34 lb/d). Range heifers tended (P = 0.12) to be heavier on May 18 (859 and 830 lb, respectively) and were heavier (P \u3c 0.05) at breeding (915 and 834 lb, respectively). Weight differences in May were a result of higher than expected gains by the Range heifers in the spring. From May 18 to June 14, Range heifers gained more (P \u3c 0.05) than Normal (2.07 and 0.32 lb/d, respectively). Synchronized conception and overall pregnancy rates were similar (P \u3e 0.25) between the Range and Normal heifers (58% vs. 50% and 91% vs. 88%, respectively). Supplement and forage costs for the Range system was similar (117/hd). Range development provides an alternative method for developing early-weaned heifers that reduces daily costs
Gourds and squashes (Cucurbita spp.) adapted to megafaunal extinction and ecological anachronism through domestication.
The genus Cucurbita (squashes, pumpkins, gourds) contains numerous domesticated lineages with ancient New World origins. It was broadly distributed in the past but has declined to the point that several of the crops' progenitor species are scarce or unknown in the wild. We hypothesize that Holocene ecological shifts and megafaunal extinctions severely impacted wild Cucurbita, whereas their domestic counterparts adapted to changing conditions via symbiosis with human cultivators. First, we used high-throughput sequencing to analyze complete plastid genomes of 91 total Cucurbita samples, comprising ancient (n = 19), modern wild (n = 30), and modern domestic (n = 42) taxa. This analysis demonstrates independent domestication in eastern North America, evidence of a previously unknown pathway to domestication in northeastern Mexico, and broad archaeological distributions of taxa currently unknown in the wild. Further, sequence similarity between distant wild populations suggests recent fragmentation. Collectively, these results point to wild-type declines coinciding with widespread domestication. Second, we hypothesize that the disappearance of large herbivores struck a critical ecological blow against wild Cucurbita, and we take initial steps to consider this hypothesis through cross-mammal analyses of bitter taste receptor gene repertoires. Directly, megafauna consumed Cucurbita fruits and dispersed their seeds; wild Cucurbita were likely left without mutualistic dispersal partners in the Holocene because they are unpalatable to smaller surviving mammals with more bitter taste receptor genes. Indirectly, megafauna maintained mosaic-like landscapes ideal for Cucurbita, and vegetative changes following the megafaunal extinctions likely crowded out their disturbed-ground niche. Thus, anthropogenic landscapes provided favorable growth habitats and willing dispersal partners in the wake of ecological upheaval.Research was supported by The Pennsylvania State University Huck Institutes of the Life Sciences and College of the Liberal Arts (G.H.P.), Wenner–Gren post-PhD Research Grant 8770 and Natural Environment Research Council Independent Research Fellowship NE/L012030/1 (to L.K.), and the Smithsonian Institution (B.D.S.). Instrumentation was funded by the National Science Foundation through Grant OCI–0821527.This is the author accepted manuscript. The final version is available from PNAS via http://dx.doi.org/10.1073/pnas.151610911
Evaluation of Reproduction and Blood Metabolites in Beef Heifers Fed Dried Distillers Grains Plus Solubles and Soybean Hulls During Late Gestation
Dried distillers grains plus solubles (DDGS) contain a significant amount of both undegradable intake protein and fat, which have both been shown to increase reproductive performance when supplemented to heifers during gestation. The mechanisms leading to enhanced reproduction when fat or UIP are supplemented have not been fully defined. The objective of this experiment was to evaluate DDGS or soybean hulls (SBH) fed during the last trimester of gestation on circulating concentrations of growth hormone (GH) and insulin-like growth factor-I (IGF-I) and reproductive efficiency. Ninety-five crossbred heifers were grouped by expected calving date, BW, BCS, and randomly assigned to DDGS or SBH (n = 6 pens per treatment). Diets were formulated to be isoenergetic and meet the nutrient requirements at d 240 of gestation. Diets were limit fed during the last trimester of gestation until parturition. Blood samples were collected prior to calving and once per week for 4 weeks following calving . Treatment had no effect on circulating concentrations of GH or IGF-I. Time influenced both GH and IGF-I. Circulating concentrations of GH were elevated at calving and decreased by 4 d after calving. Circulating concentrations of IGF-I rose for the first 2 d following calving and then decreased through d 6. At the start of the breeding season there was no difference between DDGS and SBH in the percent of heifers that had initiated estrous cycles (74% and 70%, respectively). There was a tendency for more DDGS treated heifers to become pregnant during a 64 d natural service breeding season compared to SBH treated heifers (92% vs 80%, respectively). There was no difference in the distribution of pregnancies throughout the breeding season between treatments. In summary, DDGS and SBH fed during the last trimester of pregnancy to heifers resulted in similar patterns of circulating concentrations of GH and IGF, but DDGS treated heifers tended to have improved pregnancy rates during a defined breeding season
Risk Factors for Diarrhea in Children Under Five Years of Age Residing in Peri-Urban Communities in Cochabamba, Bolivia
This study examined the relationship between childhood diarrhea prevalence and caregiver knowledge of the causes and prevention of diarrhea in a prospective cohort of 952 children \u3c 5 years of age in Cochabamba, Bolivia. The survey of caregiver knowledge found that more than 80% of caregivers were unaware that hand washing with soap could prevent childhood diarrhea. Furthermore, when asked how to keep food safe for children to eat only 17% of caregivers reported hand washing before cooking and feeding a child. Lack of caregiver awareness of the importance of practices related to hygiene and sanitation for diarrhea prevention were significant risk factors for diarrheal disease in this cohort. The knowledge findings from this study suggest that health promotion in these communities should put further emphasis on increasing knowledge of how water treatment, hand washing with soap, proper disposal of child feces, and food preparation relate to childhood diarrhea prevention
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