249 research outputs found
The extinct, giant giraffid Sivatherium giganteum: skeletal reconstruction and body mass estimation
Sivatherium giganteum is an extinct giraffid from the Plio–Pleistocene boundary of the Himalayan foothills. To date, there has been no rigorous skeletal reconstruction of this unusual mammal. Historical and contemporary accounts anecdotally state that Sivatherium rivalled the African elephant in terms of its body mass, but this statement has never been tested. Here, we present a three-dimensional composite skeletal reconstruction and calculate a representative body mass estimate for this species using a volumetric method. We find that the estimated adult body mass of 1246 kg (857—1812 kg range) does not approach that of an African elephant, but confirms that Sivatherium was certainly a large giraffid, and may have been the largest ruminant mammal that has ever existed. We contrast this volumetric estimate with a bivariate scaling estimate derived from Sivatherium's humeral circumference and find that there is a discrepancy between the two. The difference implies that the humeral circumference of Sivatherium is greater than expected for an animal of this size, and we speculate this may be linked to a cranial shift in centre of mass
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Developing an Economic Profile of Texas Shrimp Trawling Operations in The Gulf of Mexico
The annual assessment of shrimp fishing performance is important to three interrelated audiences: the regulatory community which defines the policy arena in which fishermen operate, financial institutions which extend credit, and producers. Historic, economic performance data enables policy makers to estimate the ability of producers to absorb production losses and/or increased expenses that resource management measures may mandate. Likewise, commercial lenders accustomed to using industry benchmarks can compare historic performance of a loan applicant against his peers. At the firm level, if key measures of competitiveness such as production costs, profitability, and return on assets are to be improved, producers can gain from knowing how their performance compares against industry standards. This paper describes the development of a database that meets the needs of these three audiences. Annual economic, financial, and production data are provided by cooperating vessel owners. Accrual-adjusted financial statements are the primary sources of financial and economic information while fishing records highlight production-oriented measures (e.g. days-at-sea, gallons of fuel used, pounds harvested, etc.). To create benchmarks in production costs, revenues, and equity changes, a standardized set of ratios and measures is computed that reflects the financial position and performance of trawlers over time. These ratios and measures are computed according to guidelines adopted by the Farm Financial Standards Council. With this information, the impacts of proposed regulations can be assessed both economically and financially providing a basis for communication with policy makers. Similarly, such ratios and measures allow commercial lenders and cooperators to compare individual performance against industry standards.Keywords: shrimp fishing, financial performance, economic analysi
Child obesity cut-offs as derived from parental perceptions: cross-sectional questionnaire.
BACKGROUND: Overweight children are at an increased risk of premature mortality and disease in adulthood. Parental perceptions and clinical definitions of child obesity differ, which may lessen the effectiveness of interventions to address obesity in the home setting. The extent to which parental and objective weight status cut-offs diverge has not been documented. AIM: To compare parental perceived and objectively derived assessment of underweight, healthy weight, and overweight in English children, and to identify sociodemographic characteristics that predict parental under- or overestimation of a child's weight status. DESIGN AND SETTING: Cross-sectional questionnaire completed by parents linked with objective measurement of height and weight by school nurses, in English children from five regions aged 4-5 and 10-11 years old. METHOD: Parental derived cut-offs for under- and overweight were derived from a multinomial model of parental classification of their own child's weight status against school nurse measured body mass index (BMI) centile. RESULTS: Measured BMI centile was matched with parent classification of weight status in 2976 children. Parents become more likely to classify their children as underweight when they are at the 0.8th centile or below, and overweight at the 99.7th centile or above. Parents were more likely to underestimate a child's weight if the child was black or South Asian, male, more deprived, or the child was older. These values differ greatly from the BMI centile cut-offs for underweight (2nd centile) and overweight (85th). CONCLUSION: Clinical and parental classifications of obesity are divergent at extremes of the weight spectrum
CAPOT: A flexible rapid assessment model to estimate local deposition of fish cage farm wastes
The Cage Aquaculture Particulate Output and Transport (CAPOT) model is an easy to use and flexible farm-scale model that can rapidly estimate particulate waste deposition from fish cage production. This paper describes and tests the model and demonstrates its use for Atlantic salmon (Salmo salar) and Atlantic cod (Gadus morhua). The spreadsheet-based model gives outputs for waste distribution in a variety of spatial modelling software formats, used for further analysis. The model was tested at a commercial Atlantic cod farm and commercial Atlantic salmon farm under full production conditions. Sediment trap data showed predictions, using actual recorded feed and biomass data, to be 96% (±36%) similar for Atlantic cod beyond 5 m from the cage edge, giving a satisfactory estimate of local benthic impact in the vicinity of the farm. For Atlantic salmon, using estimated production biomass and FCR (Feed Conversion Ratio) to calculate feed input, the model overestimated wastes directly beneath the cages (120% ± 148%) and underestimated beyond 5 m from the cage edge, being 48% (±42%) similar to sediment trap data. CAPOT is a suitable initial, rapid assessment model to give an overview of potential impact of particulate waste from new or expanded fish cage farms, with little operator expertise by a wide range of stakeholders
The interlayer cohesive energy of graphite from thermal desorption of polyaromatic hydrocarbons
We have studied the interaction of polyaromatic hydrocarbons (PAHs) with the
basal plane of graphite using thermal desorption spectroscopy. Desorption
kinetics of benzene, naphthalene, coronene and ovalene at sub-monolayer
coverages yield activation energies of 0.50 eV, 0.85 eV, 1.40 eV and 2.1 eV,
respectively. Benzene and naphthalene follow simple first order desorption
kinetics while coronene and ovalene exhibit fractional order kinetics owing to
the stability of 2-D adsorbate islands up to the desorption temperature.
Pre-exponential frequency factors are found to be in the range
- as obtained from both Falconer--Madix (isothermal
desorption) analysis and Antoine's fit to vapour pressure data. The resulting
binding energy per carbon atom of the PAH is 5 meV and can be identified
with the interlayer cohesive energy of graphite. The resulting cleavage energy
of graphite is ~meV/atom which is considerably larger than previously
reported experimental values.Comment: 8 pages, 4 figures, 2 table
Hydrofunctionalisation of an Aromatic Triphosphabenzene
The aromatic heterocycle 2,4,6-tri-tert-butyl-1,3,5-triphosphabenzene reacts with a series of silanes, germanes and stannanes, with weaker E-H bonds reacting in an increasingly facile manner. All react by 1,4-addition to give bicyclic products with diastereomeric ratios varying with the substrate. Density functional theory (DFT) calculations show that activation of the E-H bond occurs across the 1,4-C/P axis of the triphosphabenzene, with the small energetic differences with respect to the stereochemistry of the addition offering insight into the experimentally observed diastereomeric ratios
How humans transmit language:horizontal transmission matches word frequencies among peers on Twitter
The microbiota regulates murine inflammatory responses to toxin-induced CNS demyelination but has minimal impact on remyelination.
The microbiota is now recognized as a key influence on the host immune response in the central nervous system (CNS). As such, there has been some progress toward therapies that modulate the microbiota with the aim of limiting immune-mediated demyelination, as occurs in multiple sclerosis. However, remyelination-the regeneration of myelin sheaths-also depends upon an immune response, and the effects that such interventions might have on remyelination have not yet been explored. Here, we show that the inflammatory response during CNS remyelination in mice is modulated by antibiotic or probiotic treatment, as well as in germ-free mice. We also explore the effect of these changes on oligodendrocyte progenitor cell differentiation, which is inhibited by antibiotics but unaffected by our other interventions. These results reveal that high combined doses of oral antibiotics impair oligodendrocyte progenitor cell responses during remyelination and further our understanding of how mammalian regeneration relates to the microbiota.This work was supported by grants from UK Multiple Sclerosis Society,
The British Trust for the Myelin Project, MedImmune, The Adelson Medical
Research Foundation, Wellcome Trust, BBSRC, the Leverhulme Trust and a
core support grant from the Wellcome Trust and MRC to the Wellcome
Trust - Medical Research Council Cambridge Stem Cell Institute. CEM was
supported by grants from the Jean Shanks Foundation and the James Baird
Fund, AGF was supported by an ECTRIMS fellowship and OBZ received a
BIRAX fellowship
Identification of Mendelian inconsistencies between SNP and pedigree information of sibs
Background Using SNP genotypes to apply genomic selection in breeding programs is becoming common practice. Tools to edit and check the quality of genotype data are required. Checking for Mendelian inconsistencies makes it possible to identify animals for which pedigree information and genotype information are not in agreement. Methods Straightforward tests to detect Mendelian inconsistencies exist that count the number of opposing homozygous marker (e.g. SNP) genotypes between parent and offspring (PAR-OFF). Here, we develop two tests to identify Mendelian inconsistencies between sibs. The first test counts SNP with opposing homozygous genotypes between sib pairs (SIBCOUNT). The second test compares pedigree and SNP-based relationships (SIBREL). All tests iteratively remove animals based on decreasing numbers of inconsistent parents and offspring or sibs. The PAR-OFF test, followed by either SIB test, was applied to a dataset comprising 2,078 genotyped cows and 211 genotyped sires. Theoretical expectations for distributions of test statistics of all three tests were calculated and compared to empirically derived values. Type I and II error rates were calculated after applying the tests to the edited data, while Mendelian inconsistencies were introduced by permuting pedigree against genotype data for various proportions of animals. Results Both SIB tests identified animal pairs for which pedigree and genomic relationships could be considered as inconsistent by visual inspection of a scatter plot of pairwise pedigree and SNP-based relationships. After removal of 235 animals with the PAR-OFF test, SIBCOUNT (SIBREL) identified 18 (22) additional inconsistent animals. Seventeen animals were identified by both methods. The numbers of incorrectly deleted animals (Type I error), were equally low for both methods, while the numbers of incorrectly non-deleted animals (Type II error), were considerably higher for SIBREL compared to SIBCOUNT. Conclusions Tests to remove Mendelian inconsistencies between sibs should be preceded by a test for parent-offspring inconsistencies. This parent-offspring test should not only consider parent-offspring pairs based on pedigree data, but also those based on SNP information. Both SIB tests could identify pairs of sibs with Mendelian inconsistencies. Based on type I and II error rates, counting opposing homozygotes between sibs (SIBCOUNT) appears slightly more precise than comparing genomic and pedigree relationships (SIBREL) to detect Mendelian inconsistencies between sib
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