4,164 research outputs found

    Severe storm electricity

    Get PDF
    Successful ground truth support of U-2 overflights was been accomplished. Data have been reduced for 4 June 1984 and some of the results have been integrated into some of MSFC's efforts. Staccato lightning (multiply branched, single stroke flash with no continuing current) is prevalent within the rainfree region around the main storm updraft and this is believed to be important, i.e., staccato flashes might be an important indicator of severe storm electrification. Results from data analysis from two stations appear to indicate that charge center heights can be estimated from a combination of intercept data with data from the fixed laboratory at NSSL. An excellent data base has been provided for determining the sight errors and efficiency of NSSL's LLP system. Cloud structures, observable in a low radar reflectivity region and on a scale smaller than is currently resolved by radar, which appear to be related to electrical activity are studied

    Tauroursodeoxycholic acid exerts anticholestatic effects by a cooperative cPKC alpha-/PKA-dependent mechanism in rat liver.

    Get PDF
    Objective: Ursodeoxycholic acid (UDCA) exerts anticholestatic effects in part by protein kinase C (PKC)-dependent mechanisms. Its taurine conjugate, TUDCA, is a cPKCa agonist. We tested whether protein kinase A (PKA) might contribute to the anticholestatic action of TUDCA via cooperative cPKCa-/PKA-dependent mechanisms in taurolithocholic acid (TLCA)-induced cholestasis. Methods: In perfused rat liver, bile flow was determined gravimetrically, organic anion secretion spectrophotometrically, lactate dehydrogenase (LDH) release enzymatically, cAMP response-element binding protein (CREB) phosphorylation by immunoblotting, and cAMP by immunoassay. PKC/PKA inhibitors were tested radiochemically. In vitro phosphorylation of the conjugate export pump, Mrp2/Abcc2, was studied in rat hepatocytes and human Hep-G2 hepatoma cells. Results: In livers treated with TLCA (10 mmol/l)+TUDCA (25 mmol/l), combined inhibition of cPKC by the cPKCselective inhibitor Go¨6976 (100 nmol/l) or the nonselective PKC inhibitor staurosporine (10 nmol/l) and of PKA by H89 (100 nmol/l) reduced bile flow by 36% (p,0.05) and 48% (p,0.01), and secretion of the Mrp2/ Abcc2 substrate, 2,4-dinitrophenyl-S-glutathione, by 31% (p,0.05) and 41% (p,0.01), respectively; bile flow was unaffected in control livers or livers treated with TUDCA only or TLCA+taurocholic acid. Inhibition of cPKC or PKA alone did not affect the anticholestatic action of TUDCA. Hepatic cAMP levels and CREB phosphorylation as readout of PKA activity were unaffected by the bile acids tested, suggesting a permissive effect of PKA for the anticholestatic action of TUDCA. Rat and human hepatocellular Mrp2 were phosphorylated by phorbol ester pretreatment and recombinant cPKCa, nPKCe, and PKA, respectively, in a staurosporine-sensitive manner. Conclusion: UDCA conjugates exert their anticholestatic action in bile acid-induced cholestasis in part via cooperative post-translational cPKCa-/PKA-dependent mechanisms. Hepatocellular Mrp2 may be one target of bile acid-induced kinase activation

    Economically Optimal Distiller Grain Inclusion in Beef Feedlot Rations: Recognition of Omitted Factors

    Get PDF
    With the rapid expansion of the ethanol industry, the feeding landscape familiar to the feedlot industry is changing. While concerns regarding rising corn prices persist, many within the industry are looking at distiller’s grains, a by-product of ethanol production, to serve as a feed substitute. The question remains as to what extent these two feed sources are substitutable. The purpose of this study is to identify the economically optimal inclusion rate of distiller’s grains in beef feedlot rations, considering an array of often omitted factors. Most currently prevailing recommendation rates are strictly biologically based and frequently reference only one feeding trial. Unique economic factors considered in this research include the impact of by-product inclusion rates on animal performance (utilizing recently conducted meta-analysis from 17 relevant feeding trials), enhanced likelihood of death loss from heightened sulfur content, and manure disposal costs. Results indicate that excluding these factors can significantly impact optimal inclusion levels and that reliance on a single or few feeding trials may greatly bias results.distiller’s grains, livestock rations, manure disposal cost,

    Economically Optimal Distiller Grain Inclusion in Beef Feedlot Rations: Recognition of Omitted Factors

    Get PDF
    With the rapid expansion of the ethanol industry, the feeding landscape familiar to the feedlot industry is changing. While concerns regarding rising corn prices persist, many within the industry are looking at distillers grains, a by-product of ethanol production, to serve as a feed substitute. The question remains as to what extent these two feed sources are substitutable. The purpose of this study is to identify the economically optimal inclusion rate of distillers grains in beef feedlot rations, considering an array of often omitted factors. Most currently prevailing recommendation rates are strictly biologically based and frequently reference only one feeding trial. Unique economic factors considered in this research include the impact of by-product inclusion rates on animal performance (utilizing recently conducted meta-analysis from 17 relevant feeding trials), enhanced likelihood of death loss from heightened sulfur content, and manure disposal costs. Results indicate that excluding these factors can significantly impact optimal inclusion levels and that reliance on a single or few feeding trials may greatly bias results.Livestock Production/Industries,

    Microscopic resolution broadband dielectric spectroscopy

    Get PDF
    Results are presented for a non-contact measurement system capable of micron level spatial resolution. It utilises the novel electric potential sensor (EPS) technology, invented at Sussex, to image the electric field above a simple composite dielectric material. EP sensors may be regarded as analogous to a magnetometer and require no adjustments or offsets during either setup or use. The sample consists of a standard glass/epoxy FR4 circuit board, with linear defects machined into the surface by a PCB milling machine. The sample is excited with an a.c. signal over a range of frequencies from 10 kHz to 10 MHz, from the reverse side, by placing it on a conducting sheet connected to the source. The single sensor is raster scanned over the surface at a constant working distance, consistent with the spatial resolution, in order to build up an image of the electric field, with respect to the reference potential. The results demonstrate that both the surface defects and the internal dielectric variations within the composite may be imaged in this way, with good contrast being observed between the glass mat and the epoxy resin

    Can Streamer Blobs prevent the Buildup of the Interplanetetary Magnetic Field?

    Full text link
    Coronal Mass Ejections continuously drag closed magnetic field lines away from the Sun, adding new flux to the interplanetary magnetic field (IMF). We propose that the outward-moving blobs that have been observed in helmet streamers are evidence of ongoing, small-scale reconnection in streamer current sheets, which may play an important role in the prevention of an indefinite buildup of the IMF. Reconnection between two open field lines from both sides of a streamer current sheet creates a new closed field line, which becomes part of the helmet, and a disconnected field line, which moves outward. The blobs are formed by plasma from the streamer that is swept up in the trough of the outward moving field line. We show that this mechanism is supported by observations from SOHO/LASCO. Additionally, we propose a thorough statistical study to quantify the contribution of blob formation to the reduction of the IMF, and indicate how this mechanism may be verified by observations with SOHO/UVCS and the proposed NASA STEREO and ESA Polar Orbiter missions.Comment: 7 pages, 2 figures; accepted by The Astrophysical Journal Letters; uses AASTe

    An exploratory study of how a Korean chaebol’s learning culture facilitates customer service

    Get PDF
    This paper explains how the organizational learning concept is used by managers in a global Korean company to promote group work, information sharing and an open communication style in order to produce a high level of customer service. Previously collected data from a set of in-depth personal interviews undertaken with three senior managers in a Korean electronics company were analyzed and interpreted using the grounded theory approach, and a number of propositions are put forward. The research findings show that managers in a chaebol deploy organizational learning to identify skilled and knowledgeable staff, and improve the organization’s capability by placing emphasis on developing harmonious, mutually oriented relationships that permeate throughout the organization. Top management demand that staff identify with government economic objectives and align the organization’s strategy accordingly so that the products produced are marketable. To achieve this, the organization fosters continual interaction among managers throughout the organization’s hierarchy. The chaebol’s organizational learning model encapsulates a “corollary” (continual communication) and “tools” (cultural influence and relationship management), and manifests in a unique strategy that allows management systems to evolve naturally

    Signal specific electric potential sensors for operation in noisy environments

    Get PDF
    Limitations on the performance of electric potential sensors are due to saturation caused by environmental electromagnetic noise. The work described involves tailoring the response of the sensors to reject the main components of the noise, thereby enhancing both the effective dynamic range and signal to noise. We show that by using real-time analogue signal processing it is possible to detect a human heartbeat at a distance of 40 cm from the front of a subject in an unshielded laboratory. This result has significant implications both for security sensing and biometric measurements in addition to the more obvious safety related applications

    The Ethics of Corporate Governance

    Get PDF
    How should corporate directors determine what is the right decision? For at least the past 30 years the debate has raged as to whether shareholder value should take precedence over corporate social responsibility when crucial decisions arise. Directors face pressure, not least from ethical investors, to do the good thing when they seek to make the right choice. Corporate governance theory has tended to look to agency theory and the need of boards to curb excessive executive power to guide directors' decisions. While useful for those purposes, agency theory provides only limited guidance. Supplementing it with the alternatives - stakeholder theory and stewardship theory - tends to put directors in conflict with their legal obligations to work in the interests of shareholders. This paper seeks to reframe the discussion about corporate governance in terms of the ethical debate between consequential, teleological approaches to ethics and idealist, deontological ones, suggesting that directors are - for good reason - more inclined toward utilitarian judgments like those underpinning shareholder value. But the problems with shareholder value have become so great that a different framework is needed: strategic value, with an emphasis on long-term value creation judged from a decidedly utilitarian standpoint
    • …
    corecore