Assessment and Recommended Revision of Board Policies for Gretna Public Schools

It is commonly acknowledged that, because of the complexity of schools and the rapidity of change, the development and continual revision of written educational policies by local school boards is a necessity. Policies to guide decision making are necessary because situations or decisions repeatedly occur in school districts across the nation. Board members, parents and staff and student often have different perceptions or questions about routine procedures and complex problems

The regulatory effect of semaphorin 7A on proliferation and migration in human umbilical vein endothelial cells

Semaphorin 7A (SEMA 7A), a factor originally identified as regulating axon growth, has recently been implicated as a pro-angiogenic factor. The molecular mechanisms for this ability to stimulate angiogenesis have not been identified. This study examines if SEMA 7A can have a direct effect on vascular endothelial cells or whether it indirectly induces angiogenesis through stimulation and recruitment of macrophages as has been suggested. Using human umbilical vein endothelial cells (HUVECs), the ability of SEMA 7A to affect proliferation and migration was examined. HUVECs were exposed to SEMA 7A directly or to conditioned media collected from macrophages exposed to SEMA 7A and a cell proliferation assay was performed. Additionally, the ability of the cells to migrate was also measured using a transwell and a scratch assay. Direct exposure of HUVECs to SEMA 7A resulted in a significant decrease in cell proliferation. Preliminary results also suggest that direct exposure also results in a slight inhibitory effect on the migration of HUVECs. SEMA 7A treatment of macrophages did not result in the production of factors that stimulate HUVECs to proliferate. Additionally, our results suggest that macrophages exhibited a slight stimulation of migration in response to SEMA 7A

Inhibition of Phosphoinositide Metabolism or Chelation of Intracellular Calcium Blocks FSH-Induced but Not Spontaneous Meiotic Resumption in Mouse Oocytes

AbstractMammalian oocytes are arrested at the diplotene phase of the first meiotic division until ovulation. In the mouse, germinal vesicle breakdown (GVBD) and progression to metaphase II is thought to be triggered by a positive signal originating in the follicular cells following stimulation by the luteinizing hormone (LH) surge. Isolated, fully grown oocytes can also undergo spontaneous reinitiation of meiosisin vitroin the absence of gonadotrophin stimulation. To investigate the mechanism of meiotic resumption, inhibitors of phosphoinositide metabolism and an intracellular calcium chelator were used during maturationin vitrounder different conditions. In a series of experiments, isolated cumulus cell–oocyte complexes (COCs) maintained in meiotic arrest by hypoxanthine were induced to resume meiosis by treatment with follicle-stimulating hormone (FSH). Under these conditions, both LiCl and neomycin, which inhibit phosphoinositide hydrolysis, produced a dose-dependent inhibitory effect on meiotic resumption. Similar results were obtained when FSH-induced meiotic resumption was observed in the presence of the acetoxymethyl ester form of 1,2-bis(o-aminophenoxy)ethane-N,N,N′,N′-tetraacetic acid (BAPTA/AM), an intracellular calcium chelator. In hypoxanthine-arrested oocytes, GVBD induced by epidermal growth factor (EGF), which mimics FSH action inin vitromaturation, was also repressed by LiCl and neomycin. Conversely, meiotic resumption triggered by a pulse of 8-bromo-cyclic adenosine monophosphate (8-Br cAMP) was not affected by these two inhibitors. In experiments in which oocytes were cultured under conditions which permit spontaneous meiotic maturation, resumption of meiosis was not affected by either inhibition of phosphoinositide hydrolysis or chelation of intracellular calcium. Therefore, it appears that meiotic resumption induced by hormone stimulation requires activation of the phosphoinositide pathway and mobilization of intracellular calcium. In contrast, spontaneous maturation probably occurs through a different mechanism because it is not affected by inhibition of this signaling pathway

Impact of Changes in U.S. Grain Standards on Discounts for Insects in Stored Grain

The Federal Grain Inspection Service changed U.S. grain standards in 1988. Insect discounts given at country elevators and at terminal elevators were analyzed to determine impacts of the new standards. Insect discounts influence grain quality by affecting insect control decisions by producers and country elevator managers.Grain Inspection, Insect Discounts, Wheat, Farm Storage, Elevator Storage, Crop Production/Industries,

The Market Value of Diversified Firms in Australia

This paper refines the Berger and Ofek (1995) methodology to approximate the market value of diversified firms in Australia between 1988 and 1998. Mixed evidence is found for the diversification discount, with diversified firms trading at a discount to single segment firms using an earnings-based excess value measure and at a premium employing an assets excess value measure. Measurement errors are identified with the earning-based excess value measure and refinements are presented. Ordinary Least Squares (OLS) regression models are applied to explain the variations in the diversification results. There is strong evidence for differential pricing of diversified firms in Australia with high performing diversified firms trading at a premium to single segment firms

Launching a report on unlawful file sharing

A launch event for a scoping review of a decade of file sharing research was held by the CREATe group on 11 April 2014. Panellists were invited from stakeholder groups including industry, civil rights and technological intermediaries. The review addressed five key determinants of unlawful file sharing which were repeatedly found in the 206 reviewed studies: legal and financial, technical, experiential, social and moral. It also covered issues of social welfare and the costs and benefits to producers and consumers. The unequal coverage of different media sectors and research types, and the insufficient actual causal behavioural data, were highlighted. A subsequent discussion covered technological change, harm and issues of production. There is need for more and better evidence to support policy

Risk, benefit and moderators of the affect heuristic in a widespread unlawful activity: Evidence from a survey of unlawful file sharing behavior

Increasing the perception of legal risk via publicized litigation and lobbying for copyright law enforcement has had limited success in reducing unlawful content sharing by the public. We consider the extent to which engaging in file sharing online is motivated by the perceived benefits of this activity as opposed to perceived legal risks. Moreover, we explore moderators of the relationship between perceived risk and perceived benefits; namely trust in industry and legal regulators, and perceived online anonymity. We examine these questions via a large two-part survey of consumers of music (n = 658) and eBooks (n = 737). We find that perceptions of benefit, but not of legal risk, predict stated file sharing behavior. An affect heuristic is employed: as perceived benefit increases, perceived risk falls. This relationship is increased under high regulator and industry trust (which actually increases perceived risk in this study) and low anonymity (which also increases perceived risk). We propose that, given the limited impact of perceived legal risk upon unlawful downloading, it would be better for the media industries to target enhancing the perceived benefit and availability of lawful alternatives

A comparison of local simulations and reduced models of MRI-induced turbulence

We run mean-field shearing-box numerical simulations with a temperature-dependent resistivity and compare them to a reduced dynamical model. Our simulations reveal the co-existence of two quasi-steady states, a `quiet' state and an `active' turbulent state, confirming the predictions of the reduced model. The initial conditions determine on which state the simulation ultimately settles. The active state is strongly influenced by the geometry of the computational box and the thermal properties of the gas. Cubic domains support permanent channel flows, bar-shaped domains exhibit eruptive behaviour, and horizontal slabs give rise to infrequent channels. Meanwhile, longer cooling time-scales lead to higher saturation amplitudes.Comment: MNRAS accepted, 9 pages, 11 figure

Exact shering box solutions of MHD flows with resistivity, viscosity and cooling

Axisymmetric incompressible modes of the magneto-rotational instability (MRI) with a vertical wavenumber are exact solutions of the non-linear local equations of motion for a disk (shearing box). They are referred to as "channel solutions". Here, we generalize a class of these solutions to include energy losses, viscous, and resistive effects. In the limit of zero shear, we recover the result that torsional Alfv\'en waves are exact solutions of the non-linear equations. Our method allows the extension of these solutions into the dissipative regime. These new solutions serve as benchmarks for simulations including dissipation and energy loss, and to calibrate numerical viscosity and resistivity in the Zeus3D code. We quantify the anisotropy of numerical dissipation and compute its scaling with time and space resolution. We find a strong dependence of the dissipation on the mean magnetic field that may affect the saturation state of the MRI as computed with Zeus3D. It is also shown that elongated grid cells generally preclude isotropic dissipation and that a Courant time step smaller than that which is commonly used should be taken to avoid spurious anti-diffusion of magnetic field.Comment: 17 pages, 18 figures, MNRAS in pres