882 research outputs found

    Extreme fire weather associated with nocturnal drying in elevated coastal Terrain of California

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    The second largest fire shelter deployment in U.S. history occurred in August 2003 during the Devil Fire, which was burning in a remote and rugged region of the San Francisco Bay Area, when relative humidity abruptly dropped in the middle of the night, causing rapid fire growth. Nocturnal drying events in the higher elevations along California\u27s central coast are a unique phenomenon that poses a great risk to wildland firefighters. Single-digit relative humidity with dewpoints below -25°C is not uncommon during summer nights in this region. To provide the fire management community with knowledge of these hazardous conditions, an event criterion was established to develop a climatology of nocturnal drying and to investigate the synoptic patterns associated with these events. A lower-tropospheric source region of dry air was found over the northeastern Pacific Ocean corresponding to an area of maximum low-level divergence and associated subsidence. This dry air forms above a marine inversion and advects inland overnight with the marine layer and immerses higher-elevation terrain with warm and dry air. An average of 15-20 nocturnal drying events per year occur in elevations greater than 700m in the San Francisco Bay Area, and their characteristics are highly variable, making them a challenge to forecast

    Russian Wolves In Folktales And Literature Of The Plains A Question Of Origins

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    F or the past several years, my research associate, Robert Buchheit, and I have collected recordings of German dialects spoken by people advanced in years who immigrated to the United States and settled in the Great Plains region decades ago. Our purpose has been to acquire aural records of folk languages, to study the linguistic transformations that have occurred in them, and to preserve permanently languages that will soon disappear. In the course of our research, we have encouraged our informants to speak freely of their personal experiences, family histories, customs, and culture. The numerous recordings that we have made also include many folktales\u27 from Europe. A large proportion of our informants, most of whom reside on farms or in small towns in Nebraska, Kansas, and the Dakotas, are Germans from Russia. The ancestors of these people emigrated originally from Germany to Russia beginning in 1764 during the reign of Catherine the Great, who was herself a princess of German birth. Thousands of Germans were encouraged by the Russian government to form virtually autonomous colonies in the then sparsely populated districts north of the Black Sea and in the region of the Volga River. The migration to Russia continued into the nineteenth century until approximately 1860. Meanwhile the German colonies in Russia grew and prospered until the 1870s, when the government undertook a program of Russianization aimed at breaking down the cultural exclusiveness of the German colonies and integrating the people into Russian society. Objecting strongly to this cultural imperialism, more than one hundred thousand Russian Germans chose to emigrate to the United States, where they settled chiefly in the Great Plains region. RUSSIAN-GERMAN FOLKTALES Among the folktales that these Germans brought ·to the Great Plains are wolf stories, dozens of which Buchheit and I have recorded in recent years. They fall into two distinct groups: folktales with happy, often humorous, endings and those that end tragically as packs of famished wolves ferociously attack and devour human beings. A typical example of the first type is the story of Fritz and the wolf, told to me in German dialect by an informant in Henderson, Nebraska: On the way home Fritz encountered a wolf. What to do? He had been told that wolves do not attack dead people. And so he lay down absolutely still. The wolf stood over him, and its saliva dropped down on his head. He grabbed the wolf\u27s front paws and held them so that the wolf could not bite him, and so he walked home, carrying the wolf on his back. When he came home, he banged the wolf against the door and called out: Father, open up, I\u27ve got a live wolf on my back! Then they turned the wolf and the dogs loose, and they chased the wolf away

    Hypercholesterolemia is associated with hyperactive cardiac mTORC1 and mTORC2 signaling

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    Nutritional excess and hyperlipidemia increase the heart’s susceptibility to ischemic injury. Mammalian target of rapamycin (mTOR) controls the cellular response to nutritional status and may play a role in ischemic injury. To explore the effect of hypercholesterolemia on cardiac mTOR signaling, we assessed mTOR signaling in hypercholesterolemic swine (HC) that are also susceptible to increased cardiac ischemia-reperfusion injury. Yucatan pigs were fed a high-fat/high-cholesterol diet for 4 weeks to induce hypercholesterolemia, and mTOR signaling was measured by immunoblotting and immunofluorescence in the non-ischemic left ventricular area. Total myocardial mTOR and raptor levels were markedly increased in the HC group compared to the normocholesterolemic group, and directly correlated with serum cholesterol levels. mTOR exhibited intense perinuclear staining in myocytes only in the HC group. Hypercholesterolemia was associated with hyperactive signaling upstream and downstream of both mTOR complexes, including myocardial Akt, S6K1, 4EBP1, S6 and PKC-alpha, increased levels of cardiac hypertrophy markers, and a trend toward lower levels of myocardial autophagy. Hypercholesterolemia can now be added to the growing list of conditions associated with aberrant mTOR signaling. Hypercholesterolemia produces a unique profile of alterations in cardiac mTOR signaling, which is a potential target in cardiac diseases associated with hypercholesterolemia and nutritional excess

    A cautionary tale of low-pass sequencing and imputation with respect to haplotype accuracy

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    BACKGROUND: Low-pass whole-genome sequencing and imputation offer significant cost savings, enabling substantial increases in sample size and statistical power. This approach is particularly promising in livestock breeding, providing an affordable means of screening individuals for deleterious alleles or calculating genomic breeding values. Consequently, it may also be of value in companion animal genomics to support pedigree breeding. We sought to evaluate in dogs the impact of low coverage sequencing and reference-guided imputation on genotype concordance and association analyses.RESULTS: DNA isolated from saliva of 30 Labrador retrievers was sequenced at low (0.9X and 3.8X) and high (43.5X) coverage, and down-sampled from 43.5X to 9.6X and 17.4X. Genotype imputation was performed using a diverse reference panel (1021 dogs), and two subsets of the former panel (256 dogs each) where one had an excess of Labrador retrievers relative to other breeds. We observed little difference in imputed genotype concordance between reference panels. Association analyses for a locus acting as a disease proxy were performed using single-marker (GEMMA) and haplotype-based (XP-EHH) tests. GEMMA results were highly correlated (r ≥ 0.97) between 43.5X and ≥ 3.8X depths of coverage, while for 0.9X the correlation was lower (r ≤ 0.8). XP-EHH results were less well correlated, with r ranging from 0.58 (0.9X) to 0.88 (17.4X). Across a random sample of 10,000 genomic regions averaging 17 kb in size, we observed a median of three haplotypes per dog across the sequencing depths, with 5% of the regions returning more than eight haplotypes. Inspection of one such region revealed genotype and phasing inconsistencies across sequencing depths.CONCLUSIONS: We demonstrate that saliva-derived canine DNA is suitable for whole-genome sequencing, highlighting the feasibility of client-based sampling. Low-pass sequencing and imputation require caution as incorrect allele assignments result when the subject possesses alleles that are absent in the reference panel. Larger panels have the capacity for greater allelic diversity, which should reduce the potential for imputation error. Although low-pass sequencing can accurately impute allele dosage, we highlight issues with phasing accuracy that impact haplotype-based analyses. Consequently, if accurately phased genotypes are required for analyses, we advocate sequencing at high depth (&gt; 20X).</p

    Endurance exercise training in pulmonary hypertension increases skeletal muscle electron transport chain supercomplex assembly

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    Pulmonary hypertension is associated with pronounced exercise intolerance (decreased V ċ O2 max) that can significantly impact quality of life. The cause of exercise intolerance in pulmonary hypertension remains unclear. Mitochondrial supercomplexes are large respiratory assemblies of individual electron transport chain complexes which can promote more efficient respiration. In this study, we examined pulmonary hypertension and exercise-induced changes in skeletal muscle electron transport chain protein expression and supercomplex assembly. Pulmonary arterial hypertension was induced in rats with the Sugen/Hypoxia model (10% FiO2, three weeks). Pulmonary arterial hypertension and control rats were assigned to an exercise training protocol group or kept sedentary for one month. Cardiac function and V ċ O2 max were assessed at the beginning and end of exercise training. Red (Type 1—oxidative muscle) and white (Type 2—glycolytic muscle) gastrocnemius were assessed for changes in electron transport chain complex protein expression and supercomplex assembly via SDS- and Blue Native-PAGE. Results showed that pulmonary arterial hypertension caused a significant decrease in V ċ O2 max via treadmill testing that was improved with exercise (P \u3c 0.01). Decreases in cardiac output and pulmonary acceleration time due to pulmonary arterial hypertension were not improved with exercise. Pulmonary arterial hypertension reduced expression in individual electron transport chain complex protein expression (NDUFB8 (CI), SDHB (CII), Cox IV (CIV), but not UQCRC2 (CIII), or ATP5a (CV)) in red gastrocnemius muscle. Both red gastrocnemius and white gastrocnemius electron transport chain expression was unaffected by exercise. However, non-denaturing Blue Native-PAGE analysis of mitochondrial supercomplexes demonstrated increases with exercise training in pulmonary arterial hypertension in the red gastrocnemius but not white gastrocnemius muscle. Pulmonary arterial hypertension-induced exercise intolerance is improved with exercise and is associated with muscle type specific alteration in mitochondrial supercomplex assembly and expression of mitochondrial electron transport chain proteins

    Colon and rectal cancer incidence and water trihalomethane concentrations in New South Wales, Australia

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    BACKGROUND There is evidence, although inconsistent, that long term exposure to disinfection by products (DBPs) increases the risk of bowel cancer. No study has been conducted in Australia to examine this association and due to difference in the methods of disinfection the risk can vary across geographical regions and. This study was conducted to analyse the association of trihalomethanes (THMs) in water with colon and rectal cancer in NSW Australia. METHODS Average yearly concentrations of total and individual species of THMs were obtained for 50 local government areas (LGAs). Indirectly-standardized incidence rates of colon and rectal cancers in LGAs for the period 1995 to 2001 were regressed against mean THM concentrations lagged five years, adjusting for socioeconomic status, high risk drinking, smoking status, usual source of water and year of diagnosis, including local and global random effects within a Bayesian framework. The incidence rate ratios (IRRs) for an interquartile range (IQR) increase in THMs were estimated. RESULTS Using five year lag of exposure there was a positive association between bromoform concentration and CRC in men (IRR = 1.025, 95% CI 1.010, 1.040) but not in women (IRR = 1.003, 95% CI 0.987, 1.018). The association in men was mainly found in colon cancer with bromoform (IRR = 1.035, 95% CI 1.017, 1.053). There was no appreciable association of colorectal cancer with other species of THMs. Sensitivity analyses did not materially change the associations observed. CONCLUSION A positive association was observed between colon cancer and water bromoform concentrations in men. Given the potential population impact of such an association, further research into the relationship between THMs, particularly brominated species, and colorectal cancer is warranted.This study was conducted as part of a PhD thesis. The PhD was funded by the Endeavor International Postgraduate Research Scholarship program of the Australian Government and the University of Sydney’s international postgraduate award program and Sydney School of Public Health. The expenditure for data collection was borne by the Sydney School of Public Health, the University of Sydney. The case data were provided by the NSW central cancer registry. The exposure data were provided by the Sydney Water Corporation and the Hunter Water Corporation in NSW, Australia
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