3,881 research outputs found

    Signaling, Resource-Based Power, and Pre-IPO Organizational Change

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    The theory presented suggests that underwriters are both advisors and independent agents in the issuer’s attempt to send “signals” of quality to investors by making pre-IPO organizational changes. These pre-IPO gambits are intended to increase IPO proceeds, and preemptively address potential investor concerns that would deter them from subscribing. These organizational changes initially can financially benefit founders, early investors and underwriters. But they can also have a longterm impact that some issuers, especially founders, would prefer to avoid. Utilizing signaling and resource-based power, we find that underwriter power is significantly associated with making pre-IPO gambits and lower levels of underpricing

    Magnetic Hole Formation from the Perspective of Inverse Scattering Theory

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    The dynamics of oblique, weakly dispersive nonlinear Alfven waves in the presence of weak resistive damping are investigated numerically through an extension of the derivative nonlinear Schrodinger (DNLS) equation. It is observed numerically that the nonlinear dynamics are organized around the dynamics and allowed interactions of the underlying DNLS soliton families. There are three types of oblique Alfven solitons: the compressive two-parameter soliton and one-parameter bright soliton along with the rare factive one-parameter dark soliton. The damping of either of these compressive solitons is accompanied by the formation of one or more dark solitons. The implication of these processes is that any initial wave profile containing solitons in its Inverse Scattering Transformation representation, in the presence of weak resistive damping, will result in a leading train of dark solitons. These dark soliton shave been identified with magnetic holes, and the results described above are discussed in the context of magnetic hole observations and theory

    Fluid pressure penetration for advanced FEA of metal-to-metal seals

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    This numerical study investigates the behaviour of the contact faces in the metal-to-metal seal of a typical pressure relief valve in the commercial FE-package ANSYS. The valve geometry is simplified to an axisymmetric problem, which comprises a simple representative geometry consisting of only three components. A cylindrical nozzle, which has a valve seat on top, contacts with a disk, which is preloaded by a compressed linear spring. Analysis considerations include the effects of the Fluid Pressure Penetration (FPP) across the valve seat which exists at two different scales. In-service observations show that there is certain limited fluid leakage through the valve seat at operational pressures about 90% of the set pressure, which is caused by the fluid penetrating into surface asperities at the microscale. At the macroscale, non-linear FE-analysis using the FPP technique available in ANSYS revealed that there is also a limited amount of fluid penetrating into gap, which is caused primarily by the global plastic deformation of the valve seat. Accurate prediction of the fluid pressure profile over the valve seat is addressed in this study by considering the FPP interaction on both scales. The shape of this pressure profile introduces an additional component of the spring force, which needs to be considered to provide a reliable sealing

    Serological evidence of cross infection in a dialysis unit hepatitis-B epidemic

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    Serological evidence of cross infection in a dialysis unit hepatitis-B epidemic. This study provides serological as well as epidemiological evidence that a dialysis unit hepatitis-B epidemic was spread by cross contamination. There were 74 patients and staff who developed HB-Ag-positive hepatitis during a 28-month hospital surveillance period. Twenty-six of these cases were intimately related to the dialysis unit (21 dialysis/transplant patients and five hospital staff) and 58 were not. Representative sera from each group of cases were further tested for HB-Ag subtype specificity. Thirteen of 14 dialysis/transplant patients had subtype ay whereas ten of 15 general hospital patients had the alternate phenotype ad. All four staff who had probably acquired their infection from dialysis/transplant patients were ay subtype. Eight of the dialysis/transplant patients had never received blood. Transfusion rate in the infected dialysis patients was one-third that of leukemic patients but the hepatitis rate was higher.Preuve sérologique d'une contamination croisée dans une unité de dialyse par le virus B de l'hépatite. Ce travail apporte les preuves sérologiques et épidémiologiques de la contamination croisée d'une unité d'hémodialyse par le virus B de l'hépatite. Soixante-quatorze malades et membres de l'équipe ont développé une hépatite HB-Ag positive dans les 28 mois de la surveillance de l'hôpital. Vingt-six de ces cas ont été liés étroitement à la dialyse (21 malades de dialyse ou transplantation et 5 membres de l'équipe) et 58 ne l'étaient pas. Dans chaque groupe de cas le sérum a été étudié pour identifier les phénotypes de HB-Ag. Treize des 14 malades de dialyse ou transplantation avaient le phénotype ay alors que 10 parmi 15 des malades de l'hôpital général avaient l'autre phénotype ad. Les quatre membres de l'équipe qui avaient probablement contracté leur infection à partir de malades de transplantation ou de dialyse avaient le phénotype ay. Huit des malades de dialyse ou de transplantation n'avaient jamais reçu de sang. Le débit transfusions chez les malades en dialyse atteints par l'hépatite était le tiers de celui des malades leucémiques mais l'incidence de l'hépatite a été plus grande chez les premiers

    Tertiary Treatment of Wastewater Using Oxidation Ponds

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    The purpose of the project was to determine the value of using lagoons as a supplemental process for treating the effluent from an activated sludge wastewater treatment plant. Only tentative conclusions can be suggested since the project was not carried to completion. It appears that lagoons will have only minimal effect on the amounts of total nitrogen and phosphate in the plant effluent, although conversion of a portion of the ammonia to nitrate can be expected. However, the concentration of ammonia was never lower than that required by EPA guidelines. Some reduction of soluble BOD appears to occur, perhaps through conversion to new cell material. Suspended solids concentrations can be expected to increase during periods of algae growth. The numbers of both fecal and total coliform bacteria decreased substantially during the detention period provided by the lagoon system. Although not confirmed, it was concluded that the most probable cause for the decrease was the intensity and duration of sunlight. The lagoon served very effectively as a buffer between the treatment plant and the receiving stream, providing a considerable measure of protection to the stream even during those periods during which the plant was by-passing a portion of the inflow

    Combination GLP-1 and Insulin Treatment Fails to Alter Myocardial Fuel Selection Versus Insulin Alone in Type 2 Diabetes

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    Context Glucagon-like peptide-1 (GLP-1) and the clinically available GLP-1 agonists have been shown to exert effects on the heart. It is unclear whether these effects occur at clinically used doses in vivo in humans, possibly contributing to CVD risk reduction. Objective To determine whether liraglutide at clinical dosing augments myocardial glucose uptake alone or in combination with insulin compared to insulin alone in metformin-treated Type 2 diabetes mellitus. Design Comparison of myocardial fuel utilization after 3 months of treatment with insulin detemir, liraglutide, or combination detemir+liraglutide. Setting Academic hospital Participants Type 2 diabetes treated with metformin plus oral agents or basal insulin. Interventions Insulin detemir, liraglutide, or combination added to background metformin Main Outcome Measures Myocardial blood flow, fuel selection and rates of fuel utilization evaluated using positron emission tomography, powered to demonstrate large effects. Results We observed greater myocardial blood flow in the insulin-treated groups (median[25th, 75th percentile]: detemir 0.64[0.50, 0.69], liraglutide 0.52[0.46, 0.58] and detemir+liraglutide 0.75[0.55, 0.77] mL/g/min, p=0.035 comparing 3 groups and p=0.01 comparing detemir groups to liraglutide alone). There were no evident differences between groups in myocardial glucose uptake (detemir 0.040[0.013, 0.049], liraglutide 0.055[0.019, 0.105], detemir+liraglutide 0.037[0.009, 0.046] µmol/g/min, p=0.68 comparing 3 groups). Similarly there were no treatment group differences in measures of myocardial fatty acid uptake or handling, and no differences in total oxidation rate. Conclusions These observations argue against large effects of GLP-1 agonists on myocardial fuel metabolism as mediators of beneficial treatment effects on myocardial function and ischemia protection

    Evaluation of Plant- waxes to Estimate Forage Intake in Grazing Cattle

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    Although key to the efficiency of a cattle operation, feed intake is challenging to evaluate in a grazing setting. However, even within forage- based systems, plant- wax markers may be used to predict dietary choices and feed intake. Plant- waxes are a complex mixture of lipids found on the surface of plants. When sufficiently unique among plants, the composition of diets can be determined from the pattern of these compounds in the forages ingested. These markers were used to delineate the parts of the corn plant and, separately, 8 western rangeland grasses and legumes. Using plant waxes, the components of the corn plant were clearly distinguished. Th is technique therefore could be useful in a monoculture, such as a corn residue field, to determine the plant parts predominating in the diet. Delineating plants in a complex sward was more difficult, particularly among like species. Th e use of more markers may help to more explicitly distinguish plants within diverse pastures, such as western rangelands

    Study of mechanical aspects of leak tightness in a pressure relief valve using advanced FE-analysis

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    This paper presents a numerical study involving the deformation of contact faces in the metal-to-metal seal in a typical pressure relief valve. The valve geometry is simplified to an axisymmetric problem, which comprises a simple geometry consisting of only 3 components. A cylindrical nozzle, which has a valve seat on top, contacts with a disk, which is preloaded by a compressed linear spring. All the components are made of AISI type 316N(L) steel defined using the multilinear kinematic hardening model based on monotonic and cyclic tests at 20°C. In-service observations show that there is a limited fluid leakage through the valve seat at operational pressures about 90% of the set pressure, which is caused by the fluid penetrating into surface asperities at the microscale. Nonlinear FEA in ANSYS using the fluid pressure penetration (FPP) technique revealed that there is a limited amount of fluid penetrating into gap, which is caused by the plastic deformation of the valve seat at the macroscale. Prediction of the fluid pressure distribution over the valve seat just before the valve lift is addressed in this study considering the FPP interaction on multiscale. This is the principal scope, since it allows adjustment of the valve spring force in order to improve the leak tightness
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