1,961 research outputs found

    Regulation of Peripheral Molecular Clocks in Mammalian Tissues and In Vitro Skeletal Muscle Activation of AMP-Activated Protein Kinase via AICAR

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    Most organisms possess a common molecular machinery that governs cellular and tissue circadian rhythmicity through a roughly 24-hour transcription-translation feedback loop. It is estimated that up to 15 percent of human genes are influenced by the core clock machinery. It is likely, however, that the metabolic networks affected by the molecular clock differ according to body tissue. Recent evidence suggests that peripheral molecular clocks are governed to a greater extent by energy availability than by light and dark cycles. AMP-activated protein kinase (AMPK) acts as a cellular fuel gauge within the cell and is activated in response to exercise and fasting. AMPK can also be pharmacologically activated by 5-amino-1-β-D-ribofuranosyl-imidazole-4-carboxamide (AICAR). AMPK likely serves as an intermediary between metabolism and the molecular clock due to its activation of the rate-limiting enzyme in Nicotinamide adenine dinucleotide (NAD) biosynthesis, Nicotinamide phosphoribosyltransferase (NAMPT), and its role in PER and CRY degradation. The NAD-dependent histone deacetylase SIRT 1 inhibits the BMAL1-CLOCK complex in a NAMPT-dependent manner.The complex interplay between metabolism and peripheral clocks mediated by AMPK is beginning to be unraveled. AMPK’s tissue-specific influence on the molecular clock in skeletal muscles and other mammalian tissues requires further elucidation as it may provide insight into the etiology and treatment of metabolic disease. [excerpt

    Eccentricity evolution of giant planet orbits due to circumstellar disk torques

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    The extrasolar planets discovered to date possess unexpected orbital elements. Most orbit their host stars with larger eccentricities and smaller semi-major axes than similarly sized planets in our own solar system do. It is generally agreed that the interaction between giant planets and circumstellar disks (Type II migration) drives these planets inward to small radii, but the effect of these same disks on orbital eccentricity, e, is controversial. Several recent analytic calculations suggest that disk-planet interactions can excite eccentricity, while numerical studies generally produce eccentricity damping. This paper addresses this controversy using a quasi-analytic approach, drawing on several preceding analytic studies. This work refines the current treatment of eccentricity evolution by removing several approximations from the calculation of disk torques. We encounter neither uniform damping nor uniform excitation of orbital eccentricity, but rather a function de/dt that varies in both sign and magnitude depending on eccentricity and other solar system properties. Most significantly, we find that for every combination of disk and planet properties investigated herein, corotation torques produce negative values of de/dt for some range in e within the interval [0.1, 0.5]. If corotation torques are saturated, this region of eccentricity damping disappears, and excitation occurs on a short timescale of less than 0.08 Myr. Thus, our study does not produce eccentricity excitation on a timescale of a few Myr -- we obtain either eccentricity excitation on a short time scale, or eccentricity damping on a longer time scale. Finally, we discuss the implications of this result for producing the observed range in extrasolar planet eccentricity.Comment: 24 pages including 13 figures; accepted to ICARU

    Mapping the moral compass : the relationships between in-house lawyers' role, professional orientations, team cultures, organisational pressures, ethical infrastructure and ethical inclination

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    This is a survey of 400 in-house lawyers working in public, third and commercial sectors. We set out here the findings at the highest level. A number of organisations assisted with the distribution of the survey. This report provides a unique profile of real differences within the in-house community. We examine individual and team orientations to the in-house role; the invocation of professional principles; and ethical infrastructure, ethical pressure and relationships with the employer. We relate these to externally validated indicators of ethical inclination: (i) moral attentiveness (the extent to which people deal with problems as moral problems and the extent to which people identify moral problems); and (ii) moral disengagement (the extent to which people are inclined to morally disengage to behave unethically without feeling distress). It is as rich a picture of what it means to be an ethical inhouse lawyer as has ever been attempted. A more detailed summary and discussion of our findings is found in the final chapter of the main report for those who would like to know more but do not have the appetite or time to read the whole report. Through this research we profile the characteristics of individuals, teams and environments most associated with a stronger or weaker inclination to behave ethically. It is important to emphasise that this mapping of the 'moral compass' of in-house lawyers shows that ethicality is associated with individual and professional notions of the in-house role but also with team orientations and the broader organisational environment. Ethicality is both a systemic and individual phenomenon. We think the systemic lesson is important: there is too much emphasis in legal circles on thinking that ethics is about being the right sort of individual. That kind of thinking is complacent and dangerous. As we show here, individuals, systems and cultures mesh together in meaningful and measurable ways to increase or reduce ethical risk. As numerous corporate scandals have shown, such ethical risk puts individual lawyers at risk of professional misconduct but it also encourages poor quality decision-making for the organisations that employ in-house lawyers: short-termism and sharp practice can lead to catastrophic error

    Modeled El Niño-Southern Oscillation Effects on Grain Sorghum under Varying Irrigation Strategies and Cultural Practices

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    Equatorial sea surface temperatures vary systematically to cause the El Niño southern oscillation (ENSO) that produces predictable weather patterns in North America and may permit longrange climate predictions and eventual proactive summer crop irrigation management. The declining Ogallala Aquifer in the Southern High Plains and consequently limited well capacities challenge producers to adapt cropping practices for irrigation that doesn’t meet crop water demand. Our objective was to evaluate sorghum [Sorghum bicolor (L.) Moench] yield response to ENSO climate-informed management of cultural practices and irrigation strategies on a Pullman soil (fine, mixed, superactive, thermic Torrertic Paleustoll). We used the simulation model SORKAM and long-term (1961–2000) weather records from Bushland, TX, classified by ENSO phase to calculate sorghum grain yields for all combinations of irrigation levels (0.0, 2.5, 3.75, or 5.0 mm d–1), planting day of year (DOY = 135, 156, 176), and cultivar maturity (early, 95 d; medium, 105 d; late, 120 d). Using the September–November Oceanic Niño Index (ONI) to identify ENSO phase, La Niña years had 50 mm less precipitation and a corresponding 14.5% reduction in overall yield to 4550 kg ha–1 for sorghum planted at 16 plants m–2 population. Late maturing cultivars and late planting led to sorghum freeze injury and reduced yields regardless of ENSO phase. While yields consistently increased with irrigation, we conclude that concentrating water to irrigate an area partitioned 2:1 or 1:1 at 3.75- or 5.0-mm d–1 with complementary dryland produced \u3e30% more grain, overall, than uniformly irrigating an area at 2.5 mm d–1

    Meteoroid Bulk Density and Ceplecha Types

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    Determination of asteroid bulk density is an important aspect of NEO characterization, yet difficult to measure. As a fraction of meteoroids originate from asteroids (including some NEOs), a study of meteoroid bulk densities can potentially provide useful insights into the densities of NEOs and PHOs in lieu of mutual perturbations, satellite, or expensive spacecraft missions. NASA's Meteoroid Environment Office characterizes the meteoroid environment for the purpose of spacecraft risk and operations. To accurately determine the risk, a distribution of meteoroid bulk densities are needed. This is not trivial to determine. If the particle survives to the ground the bulk density can be directly measured, however only the most dense particles land on the Earth. The next best approach is to model the meteor's ablation, which is not straightforward. Clear deceleration is necessary to do this and there are discrepancies in results between models. One approach to a distribution of bulk density is to use a measured proxy for the densities, then calibrate the proxy with known densities from meteorite falls, ablation modelling, and other sources. An obvious proxy choice is the Ceplecha type, K(sub B), thought to indicate the strength of a meteoroid. KB is frequented cited as a good proxy for meteoroid densities, but we find it is poorly correlated with density. However, a distinct split by dynamical type was seen with Jovian Tisserand parameter, T(sub J), with meteoroids from Halley Type comets (T(sub J less than 2 ) exhibiting much lower densities than those originating from Jupiter and asteroids (T(sub J greater than 2)

    The ethical identity of law students

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    This is the author accepted manuscript. The final version is available from the publisher via the DOI in this recordThis paper uses measures of values, moral outlook and professional identity to explore the ethical and professional identity of law students. We do so in two jurisdictions, surveying 441 students studying in England and Wales and 569 students studying in the US. The survey covers the first and final years of an undergraduate law degree and the postgraduate vocational stage in England and Wales, as well as students in all years of the JD programme in the US. We explore whether law students towards the end of their legal education have ethical identities predictive of less ethical conduct than those at the beginning of their legal education; whether law students intending careers in business law have values and profiles consistent with less ethical conduct than those intending to work for government or individuals; and what factors might explain these differences in ethical outlook. Our findings suggest that ethical identity is strongly associated with gender and career intentions. They also suggest weaker moral identities for students intending to practise business law. Ultimately, our findings support a conclusion that is more nuanced than the predominant theses about the impact of legal education on student ethicality which tend to suggest legal education diminishes ethicality

    Pine straw yields and economic benefits when added to traditional wood products in loblolly, longleaf and slash pine stands

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    Paper presented at the 12th North American Agroforesty Conference, which was held June 4-9, 2011 in Athens, Georgia.In Ashton, S. F., S.W. Workman, W.G. Hubbard and D.J. Moorhead, eds. Agroforestry: A Profitable Land Use. Proceedings, 12th North American Agroforestry Conference, Athens, GA, June 4-9, 2011.Many forest landowners have the opportunity to manage their loblolly, longleaf and slash pine stands for pine straw (fresh undecomposed needles; the litter layer) for additional revenues. Pine straw is used primarily as mulch in landscaping and has grown in revenues paid to landowners from 15.5millionin1999to15.5 million in 1999 to 81 million in 2009 in Georgia. Pine straw is typically sold by the acre or by the bale. Selling pine straw by the acre is advantageous for absentee landowners. Selling pine straw by the bale can generate more annual income but bale counts need to be accurate and bale size must be clearly defined. Recent (2005-09) per acre revenues range from 50to50 to 125/year. Rectangular (13x13x28 inches) bale prices range from 0.25to0.25 to 0.40 for loblolly, 0.50to0.50 to 1.25 for longleaf, and 0.50to0.50 to 0.65 for slash pine in Georgia. Per rake yields from loblolly stands tend to be 15 to 30% greater (150 to 425 bales/acre) than slash (120 to 375 bales/acre) and longleaf pine (100 to 350 bales/acre). Pine straw raking starts at canopy closure continuing to the first thinning, generating from 300/acretoover300/acre to over 1000/acre in new income.E. David Dickens (1), David J. Moorhead (1), Charles T. Bargeron (1),and Bryan C. McElvany (2) ; 1. Warnell School of Forestry & Natural Resources. 2. College of Agriculture & Environmental Sciences, The University of Georgia, Statesboro, Tifton, and Soperton, GA.Includes bibliographical references

    Forest Resources Digital Information System

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    Forestry Images, the digitized documented forest health image archive, was developed with the aim to gather, create, maintain, and distribute digital information as tools to enhance and complement information exchange and educational activities. The Forestry Images System exists under the umbrella of Bugwood Network (Bargeron, Douce, & Moorhead, 2000). The increased volume of images and its usage statistics required major changes to enhance the system access, better content management, and security. The enhanced system is standard compliant based on recommendations from the World Wide Web Consortium (W3C) and the U.S. government Section 508
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