2,639 research outputs found

    Numerical generation of two-dimensional grids by the use of Poisson equations with grid control at boundaries

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    A method for generating boundary-fitted, curvilinear, two dimensional grids by the use of the Poisson equations is presented. Grids of C-type and O-type were made about airfoils and other shapes, with circular, rectangular, cascade-type, and other outer boundary shapes. Both viscous and inviscid spacings were used. In all cases, two important types of grid control can be exercised at both inner and outer boundaries. First is arbitrary control of the distances between the boundaries and the adjacent lines of the same coordinate family, i.e., stand-off distances. Second is arbitrary control of the angles with which lines of the opposite coordinate family intersect the boundaries. Thus, both grid cell size (or aspect ratio) and grid cell skewness are controlled at boundaries. Reasonable cell size and shape are ensured even in cases wherein extreme boundary shapes would tend to cause skewness or poorly controlled grid spacing. An inherent feature of the Poisson equations is that lines in the interior of the grid smoothly connect the boundary points (the grid mapping functions are second order differentiable)

    Simplified clustering of nonorthogonal grids generated by elliptic partial differential equations

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    A simple clustering transformation is combined with the Thompson, Thames, and Mastin (TTM) method of generating computational grids to produce controlled mesh spacings. For various practical grids, the resulting hybrid scheme is easier to apply than the inhomogeneous clustering terms included in the TTM method for this purpose. The technique is illustrated in application to airfoil problems, and listings of a FORTRAN computer code for this usage are included

    Use of hyperbolic partial differential equations to generate body fitted coordinates

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    The hyperbolic scheme is used to efficiently generate smoothly varying grids with good step size control near the body. Although only two dimensional applications are presented, the basic concepts are shown to extend to three dimensions

    The Enduring and Elusive Quest for a General Theory of Leadership: Initial Efforts and New Horizons

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    When the idea of convening a group of scholars to formulate a general theory of leadership was first proposed, one of those who eventually became a key member remarked that the idea of such a project was \u27quixotic\u27. Professor Joanne Ciulla used the term exactly as it is defined - as the American Heritage Dictionary (2009) has it, \u27idealistic or romantic without regard to practicality.\u27 What a charming, silly idea. And in the end, the quest and idealism endures but the goal of a general theory remains elusive. However, as Ciulla herself documents, we went far, and learned a great deal along the way

    Calcium(II)3 (3,5-Diisopropylsalicylate)6(H2O)6 Activates Nitric Oxide Synthase: An Accounting for its Action in Decreasing Platelet Aggregation

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    Purposes of these studies were first; to determine whether or not Calcium(II)3 (3,5- diisopropylsalicylate)6(H2O)6 [Ca(II)3(3,5-DIPS)6], a lipophilic calcium complex, could decrease activated-platelet aggregation, and second; to determine whether or not it is plausible that Ca(II)3(3,5-DIPS)6 decreases activated-platelet aggregation by facilitating the synthesis of Nitric Oxide (NO) by Nitric Oxide Synthase (NOS). The influence of Ca(II)3(3,5-DIPS)6 on the initial rate of activated-platelet aggregation was determined by measuring the decrease in rate of increase in transmission at 550 nm for a suspension of Thrombin-CaCl2 activated platelets following the addition of 0, 50, 100, 250, or 500 ÎĽM Ca(II)3(3,5-DIPS)6. To establish that the Ca(lI)3(3,5- DIPS)6-mediated decrease in aggregation was due to activation of NOS, the effect of Ęź-NMMA, an inhibitor of NOS, on the inhibition of platelet aggregation by Ca(II)3(3,5-DIPS)6 was determined using a suspension of activated platelets contaimng 0 or 250 ÎĽM Ca(II)3(3,5-DIPS)6 without or with 1 mM Ęź-NMMA. An in vitro Bovine Brain NOS reaction mixture, containing CaCl2 for the activation of Phosphodiesterase-3' ,5'-Cyclic Nucleotide Activator required for the activation of NOS, was used to determine whether or not Ca(II)3(3,5-DIPS)6 could be used as a substitute for the addition of Ca. The decrease in absorbance at 340 nm, lambda maximum for NADPH, was measured to determine NOS activity following the addition of NOS to the complete reaction mixture containing either CaCl2, Ca(II)3(3,5-DIPS)6, or neither Ca compound. Increasing the concentration of Ca(II)3(3,5-DIPS)6 caused a concentration related decrease in activated platelet aggregation. The addition of Ęź-NMMA to activated platelets, in the absence of Ca(II)3(3,5-DIPS)6, caused a 129% increase in initial rate of platelet aggregation. The initial rate of platelet aggregation decreased 74% with the addition of 250 ÎĽM Ca(II)3(3,5-DIPS)6 and the addition of Ęź-NMMA plus 250 ÎĽM Ca(II)3(3,5-DIPS)6 caused a 197% decrease in initial rate of aggregation compared to the initial rate observed width the presence of 1 mM Ęź-NMMA alone. There was only a small, 27%, increase in initial rate of 0.4 mM NADPH oxidation when 0.9 mM CaCl2 was added to the NOS reaction mixture in comparison to the initial rate of NADPH oxidation with no addition of CaCI2. Addition of an equivalent amount of Ca in the form of Ca(II)3(3,5-DIPS)6, 333 ÎĽM, caused a 37% increase in initial rate of NADPH oxidation compared to the addition of 0.9 mM CaCl2. Addition of increasing concentrations of Ęź-NMMA plus 0.9 mM CaCl2 or 333 ÎĽM Ca(II)3(3,5-DIPS)6 to the NOS reaction mixture caused a concentration related increase in initial rate of NADPH oxidation. Addition of Ęź-NMMA while expected to decrease NADPH oxidation actually increased the rate of NADPH oxidation. Additions of 133 ÎĽM or 267 ÎĽM Ca(II)3(3,5- DIPS)6 also caused concentration related increases in initial rate of NADPH oxidation in the presence of 113 ÎĽM Ęź-NMMA. However, the addition of 533 ÎĽM Ca(II)3(3,5-DIPS)6 caused a dramatic decrease in initial rate of NADPH oxidation by NOS. It is concluded that: 1) Ca(II)3(3,5- DIPS)6 activates platelet NOS in preventing platelet aggregation, 2) in vitro NOS activity can be observed spectrophotometrically by following the consumption of NADPH as a decrease in absorbance at 340 nm, 3) Ca(II)3(3,5-DIPS)6 plays a role in enhancing Bovine Brain NOS activity resulting in an increased rate of NADPH oxidation by NOS, 4) Ca(II)3(3,5-DIPS)6 is a useful form of Ca in activating NOS and superior to CaCl2 with regard to the facilitation of a NADPH oxidation, and 5) Ęź-NMMA stimulates Bovine Brain NOS activity rather than causing an inhibition of this enzyme and must serve as a reducible substrate for Bovine Brain NOS

    Review of methods applicable to the assessment of mold exposure to children.

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    This article presents discussion of the assessment of the exposure of children to fungi, substances derived from fungi, and the environmental conditions that may lead to exposure. The principles driving investigations of fungal contamination and subsequent exposure are presented as well as guidelines for conducting these investigations. A comprehensive description of available research sampling and analysis techniques is also presented

    Down-Regulation of Porcine Heart Diaphorase Reactivity by Trimanganese Hexakis(3,5-Diisopropylsalicylate), Mn3(3,5-DIPS)6, and Down-Regulation of Nitric Oxide Synthase Reactivity by Mn3(3,5-DIPS)6 and Cu(II)2(3,5-DIPS)4

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    Purposes of this work were to examine the plausible down-regulation of porcine heart diaphorase (PHD) enzyme reactivity and nitric oxide synthase (NOS) enzyme reactivity by trimanganese hexakis(3,5-diisopropylsalicylate), [Mn3(3,5-DIPS)6] as well as dicopper tetrakis(3,5- diisopropylsalicylate, [Cu(II)2(3,5-DIPS)4] as a mechanistic accounting for their pharmacological activities

    “Thank you, Marojejy:” affective learning outcomes of student participants in place-based field trips to Marojejy National Park

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    Evaluations of conservation education programmes are most often concerned within the cognitive domain, where logical learning takes place. In place-based education, emphasis is instead placed on learning in multiple domains, including the cognitive and affective domains. Here, we  quantitatively and qualitatively evaluate student learning in the affective domain following a series of short educational trips to Marojejy National  Park, Northeast Madagascar. Student responses to the prompt “write about your trip to Marojejy” were evaluated for content, including emotional  responses using cultural consensus, saliency scoring, and qualitative evaluation. The most salient term used in responses were “a good trip”. when  tested 1.5 to 2 weeks after their trip. Students wrote about the emotional impact of the trip in four out of five levels of the affective domain. Our findings highlight the value of place-based education for learning in the affective domain. We demonstrated that even over a brief period of three  days, placebased conservation education can have a marked impact on the values and emotions of participants. Les Ă©valuations de programmes d’éducation en matière de prĂ©servation sont le plus souvent axĂ©es sur le domaine cognitif, lĂ  oĂą s’effectue  l’apprentissage logique. Dans l’éducation effectuĂ©e sur place, l’accent est au contraire mis sur un apprentissage multidisciplinaire, qui inclut Ă  la  fois les domaines cognitifs et affectifs. Ici, nous Ă©valuons de façon quantitative et qualitative l’apprentissage des Ă©tudiants dans le domaine affectif  en suivant une sĂ©rie de brèves excursions Ă  but Ă©ducatif au Parc national de Marojejy, dans le Nord-Est de Madagascar. Les rĂ©ponses des Ă©tudiants  Ă  l’instruction « Parlez-nous de votre excursion Ă  Marojejy » ont fait l’objet d’une Ă©valuation tenant Ă©galement compte des aspects Ă©motionnels, sur  la base du consensus culturel, du score de saillance et du point de vue qualitatif. L’expression la plus saillante utilisĂ©e dans les rĂ©ponses a Ă©tĂ© «  bonne excursion » dans les tests effectuĂ©s 1,5 Ă  2 semaines après leur retour. Les Ă©tudiants ont relatĂ© l’impact Ă©motionnel de l’excursion dans  quatre des cinq niveaux du domaine affectif. Nos rĂ©sultats mettent en Ă©vidence la valeur d’une Ă©ducation sur place pour un apprentissage au  niveau affectif. Nous avons dĂ©montrĂ© que mĂŞme après une brève pĂ©riode de trois jours, l’éducation en matière de prĂ©servation peut avoir,  lorsqu’elle est effectuĂ©e sur place, un impact significatif sur les valeurs et les Ă©motions des participants
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