968 research outputs found

    Duties Of The Business Teacher In Small Texas High Schools

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    The curriculum of all Texas high schools have been expanded, and with this expansion, the duties of all teachers have become more diversified. However, the snail high school is faced with many unique problems as a result of the greatly expanded curriculum. Foremost among these problems is that of providing a well-rounded academic program for a small student body with a limited staff of teachers. The enrollment of the small high school of necessity limits the teaching staff, and as a result, teachers trained specifically in one area are often assigned to teach subjects in a second or third area. This investigation will seek to determine the undergraduate preparation of the business teacher in the small high school and to analyze the relationship of his training to the curricular and extra-curricular duties to which the teacher is assigned. Purposes of the Study The purposes of this investigation are 1. To determine the duties, curricular and extra-curricular, of the business teacher in the small high schools of Texas. 2, To determine the relationship of these duties to the undergraduate college training of these teachers, 3. To collect Information regarding the duties of the business teacher that might possibly provide help in the training of prospective business teachers for small high schools. Importance of the Study Many prospective business education teachers earn their degrees with the idea of teaching only business subjects. If a position is secured in a small high school, business teachers may be called upon to teach subjects or to direct student activities for which their undergraduate training in business has left them totally unprepared. In order for a teacher to be properly trained, it is necessary to acquire knowledge as to the duties which he might be assigned to perform. It then becomes necessary to acquire information regarding the curricular and extracurricular duties that teachers of business in small high schools are now performing, This investigation will seek to point out the duties that teachers of business in small high schools perform which have no direct relationship to the training received in business

    Wheat middlings in high concentrate rations: digestibility and ruminal metabolism

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    Six medium-framed steers, fitted with ruminal cannulae were used in a 6 × 6 Latin square design and fed the following six high concentrat e (90%) rations: control; 5, 10, or 15% pelleted wheat middlings (WM) replacing the concentrate (dry rolled corn); and 5 or 10% pelleted WM replacing the roughage (chopped alfalfa hay). Dry matter (DM), organic matter (OM), and starch digestibilities decreased linearly when increasing levels of WM replaced the concentrate , but replacing the roughage increased DM and OM digestibilities linearly. WM could replace only up to 5 % of the concentrate without reducing nutrient digestibilities, but complete (10% WM) replacement of the roughage increased nutrient digestibilities

    Glutathione metabolism is essential for self-renewal and chemoresistance of pancreatic cancer stem cells

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    BACKGROUND Cellular metabolism regulates stemness in health and disease. A reduced redox state is essential for self-renewal of normal and cancer stem cells (CSCs). However, while stem cells rely on glycolysis, different CSCs, including pancreatic CSCs, favor mitochondrial metabolism as their dominant energy-producing pathway. This suggests that powerful antioxidant networks must be in place to detoxify mitochondrial reactive oxygen species (ROS) and maintain stemness in oxidative CSCs. Since glutathione metabolism is critical for normal stem cell function and CSCs from breast, liver and gastric cancer show increased glutathione content, we hypothesized that pancreatic CSCs also rely on this pathway for ROS detoxification. AIM To investigate the role of glutathione metabolism in pancreatic CSCs. METHODS Primary pancreatic cancer cells of patient-derived xenografts (PDXs) were cultured in adherent or CSC-enriching sphere conditions to determine the role of glutathione metabolism in stemness. Real-time polymerase chain reaction (PCR) was used to validate RNAseq results involving glutathione metabolism genes in adherent vs spheres, as well as the expression of pluripotency-related genes following treatment. Public TCGA and GTEx RNAseq data from pancreatic cancer vs normal tissue samples were analyzed using the webserver GEPIA2. The glutathione-sensitive fluorescent probe monochlorobimane was used to determine glutathione content by fluorimetry or flow cytometry. Pharmacological inhibitors of glutathione synthesis and recycling [buthionine-sulfoximine (BSO) and 6-Aminonicotinamide (6-AN), respectively] were used to investigate the impact of glutathione depletion on CSC-enriched cultures. Staining with propidium iodide (cell cycle), Annexin-V (apoptosis) and CD133 (CSC content) were determined by flow cytometry. Self-renewal was assessed by sphere formation assay and response to gemcitabine treatment was used as a readout for chemoresistance. RESULTS Analysis of our previously published RNAseq dataset E-MTAB-3808 revealed up-regulation of genes involved in the KEGG (Kyoto Encyclopedia of Genes and Genomes) Pathway Glutathione Metabolism in CSC-enriched cultures compared to their differentiated counterparts. Consistently, in pancreatic cancer patient samples the expression of most of these up-regulated genes positively correlated with a stemness signature defined by NANOG, KLF4, SOX2 and OCT4 expression (P < 10-5). Moreover, 3 of the upregulated genes (MGST1, GPX8, GCCT) were associated with reduced disease-free survival in patients [Hazard ratio (HR) 2.2-2.5; P = 0.03-0.0054], suggesting a critical role for this pathway in pancreatic cancer progression. CSC-enriched sphere cultures also showed increased expression of different glutathione metabolism-related genes, as well as enhanced glutathione content in its reduced form (GSH). Glutathione depletion with BSO induced cell cycle arrest and apoptosis in spheres, and diminished the expression of stemness genes. Moreover, treatment with either BSO or the glutathione recycling inhibitor 6-AN inhibited self-renewal and the expression of the CSC marker CD133. GSH content in spheres positively correlated with intrinsic resistance to gemcitabine treatment in different PDXs r = 0.96, P = 5.8 × 1011). Additionally, CD133+ cells accumulated GSH in response to gemcitabine, which was abrogated by BSO treatment (P < 0.05). Combined treatment with BSO and gemcitabine-induced apoptosis in CD133+ cells to levels comparable to CD133- cells and significantly diminished self-renewal (P < 0.05), suggesting that chemoresistance of CSCs is partially dependent on GSH metabolism. CONCLUSION Our data suggest that pancreatic CSCs depend on glutathione metabolism. Pharmacological targeting of this pathway showed that high GSH content is essential to maintain CSC functionality in terms of self-renewal and chemoresistance

    Generalized Gravi-Electromagnetism

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    A self consistant and manifestly covariant theory for the dynamics of four charges (masses) (namely electric, magnetic, gravitational, Heavisidian) has been developed in simple, compact and consistent manner. Starting with an invariant Lagrangian density and its quaternionic representation, we have obtained the consistent field equation for the dynamics of four charges. It has been shown that the present reformulation reproduces the dynamics of individual charges (masses) in the absence of other charge (masses) as well as the generalized theory of dyons (gravito - dyons) in the absence gravito - dyons (dyons). key words: dyons, gravito - dyons, quaternion PACS NO: 14.80H

    Motion of Bound Domain Walls in a Spin Ladder

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    The elementary excitation spectrum of the spin-12\frac{1}{2} antiferromagnetic (AFM) Heisenberg chain is described in terms of a pair of freely propagating spinons. In the case of the Ising-like Heisenberg Hamiltonian spinons can be interpreted as domain walls (DWs) separating degenerate ground states. In dimension d>1d>1, the issue of spinons as elementary excitations is still unsettled. In this paper, we study two spin-12\frac{1}{2} AFM ladder models in which the individual chains are described by the Ising-like Heisenberg Hamiltonian. The rung exchange interactions are assumed to be pure Ising-type in one case and Ising-like Heisenberg in the other. Using the low-energy effective Hamiltonian approach in a perturbative formulation, we show that the spinons are coupled in bound pairs. In the first model, the bound pairs are delocalized due to a four-spin ring exchange term in the effective Hamiltonian. The appropriate dynamic structure factor is calculated and the associated lineshape is found to be almost symmetric in contrast to the 1d case. In the case of the second model, the bound pair of spinons lowers its kinetic energy by propagating between chains. The results obtained are consistent with recent theoretical studies and experimental observations on ladder-like materials.Comment: 12 pages, 7 figure

    Spin-orbit induced backflow in neutron matter with auxiliary field diffusion Monte Carlo

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    The energy per particle of zero-temperature neutron matter is investigated, with particular emphasis on the role of the L⃗⋅S⃗\vec L\cdot\vec S interaction. An analysis of the importance of explicit spin--orbit correlations in the description of the system is carried out by the auxiliary field diffusion Monte Carlo method. The improved nodal structure of the guiding function, constructed by explicitly considering these correlations, lowers the energy. The proposed spin--backflow orbitals can conveniently be used also in Green's Function Monte Carlo calculations of light nuclei.Comment: 4 pages, 1 figur

    <i>Vibrio communis</i> sp. nov., isolated from the marine animals <i>Mussismilia hispida, Phyllogorgia dilatata, Palythoa caribaeorum, Palythoa variabilis</i> and <i>Litopenaeus vannamei</i>

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    Eight Vibrio isolates originating from the marine corals Mussismilia hispida and Phyllogorgia dilatata and the zoanthids Palythoa caribaeorum and Palythoa variabilis in Brazil and the Pacific white shrimp (Litopenaeus vannamei) in Ecuador were studied by means of a polyphasic approach. The novel isolates formed a tight monophyletic group in the genus Vibrio and were closely related to species of the Vibrio harveyi group, to which they showed more than 99?% 16S rRNA gene sequence similarity. Analysis based on concatenated sequences of the following seven genes, 16S rRNA, gyrB, recA, rpoA, topA, pyrH and mreB (5633 bp in length), showed clear separation between the isolates and species of the V. harveyi group. Amplified fragment length polymorphism (AFLP) analysis, performed previously, revealed that a representative isolate of this group, LMG 20370, was clearly separate from known Vibrio species (it belonged to the so-called AFLP cluster A31). DNA–DNA hybridization (DDH) experiments with representative isolates and type strains of the V. harveyi species group revealed high DDH between the novel isolates (more than 74?%) and less than 70?% DDH towards type strains of related Vibrio species, proving the novel species status of the isolates. Phenotypically, the novel species belongs to the arginine dihydrolase (A)-negative, lysine decarboxylase (L)-positive and ornithine decarboxylase (O)-positive (A-/L+/O+) cluster reported previously. Most species of the V. harveyi group (i.e. Vibrio rotiferianus, V. harveyi, V. parahaemolyticus and V. alginolyticus) also belong to this A-/L+/O+ cluster. However, several phenotypic features can be used for the identification of the novel species. In contrast to its closest phylogenetic neighbours, the novel species exhibits esterase (C4) and N-acetyl-ß-glucosaminidase activities, but it does not produce acetoin, does not use citrate, a-ketoglutaric acid or propionic acid and does not ferment melibiose. The novel species can also be differentiated on the basis of the presence of the fatty acids C17?:?0, C17?:?1?8c, iso-C17?:?0 and iso-C13?:?0 and the absence of the fatty acid C18?:?0. The name Vibrio communis sp. nov. is proposed for this taxon. Strain R-40496T (=LMG 25430T =CAIM 1816T) is the type strain

    The primary structure of three hemoglobin chains from the indigo snake (Drymarchon corais erebennus, Serpentes): First evidence for αD chains and two β chain types in snakes

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    The hemoglobin of the indigo snake (Drymarchon corais erebennus, Colubrinae) consists of two components, HbA and HbD, in the ratio of 1:1. They differ in both their alpha and beta chains. The amino acid sequences of both alpha chains (alpha(A) and alpha(D)) and one beta chain (betaI) were determined. The presence of an alpha(D)chain in a snake hemoglobin is described for the first time. A comparison of all snake beta chain sequences revealed the existence of two paralogous beta chain types in snakes as well, which are designated as betaI and betaII type. For the discussion of the physiological properties of Drymarchon hemoglobin, the sequences were compared with those of the human alpha and beta chains and those of the closely related water snake Liophis miliaris where functional data are available. Among the heme contacts, the substitution alpha(D)58(E7)His--&gt;Gln is unusual but most likely without any effect. The residues responsible for the main part of the Bohr effect are the same as in mammalian hemoglobins. In each of the three globin chains only two residues at positions involved in the alpha1/beta2 interface contacts, most important for the stability and the properties of the hemoglobin molecule, are substituted with regard to human hemoglobin. On the contrary, nine, eleven, and six alpha1/beta1 contact residues are replaced in the alpha(A), alpha(D), betaI chains, respectively

    Weak Localization Effect in Superconductors by Radiation Damage

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    Large reductions of the superconducting transition temperature TcT_{c} and the accompanying loss of the thermal electrical resistivity (electron-phonon interaction) due to radiation damage have been observed for several A15 compounds, Chevrel phase and Ternary superconductors, and NbSe2\rm{NbSe_{2}} in the high fluence regime. We examine these behaviors based on the recent theory of weak localization effect in superconductors. We find a good fitting to the experimental data. In particular, weak localization correction to the phonon-mediated interaction is derived from the density correlation function. It is shown that weak localization has a strong influence on both the phonon-mediated interaction and the electron-phonon interaction, which leads to the universal correlation of TcT_{c} and resistance ratio.Comment: 16 pages plus 3 figures, revtex, 76 references, For more information, Plesse see http://www.fen.bilkent.edu.tr/~yjki
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