15,297 research outputs found

    The knowledge, the will and the power : a plan of action to meet the HIV prevention needs of Africans living in England

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    The Knowledge, The Will and The Power is a statement of what we, the NAHIP Partners, plan to do to prevent HIV transmissions occurring during sexual activity among the diverse population of Africans living in England (Chapter 1). We describe the size and context of Africans living in England (Chapter 2), the size of the HIV epidemic and the number of new infections occurring (Chapter 3), as well as the behaviours and facilitators of new infections (Chapter 4). We then articulate how the NAHIP partners intend to influence future behaviours (Chapter 5). The final three chapters describe what is required in order to meet the HIV prevention needs of individual African people (Chapter 6), of NAHIP partner organisations (Chapter 7) and of those undertaking decisions related to policy, planning and research (Chapter 8)

    Influence of Dielectric Environment upon Isotope Effects onGlycoside Heterolysis: Computational Evaluation and AtomicHessian Analysis

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    Isotope effects depend upon the polarity of the bulk medium in which a chemical process occurs. Implicit solvent calculations with molecule-shaped cavities show that the equilibrium isotope effect (EIE) for heterolysis of the glycosidic bonds in 5′-methylthioadenosine and in 2-(p-nitrophenoxy)tetrahydropyran, both in water, are very sensitive in the range 2 ≤ ε ≤ 10 to the relative permittivity of the continuum surrounding the oxacarbenium ion. However, different implementations of nominally the same PCM method can lead to opposite trends being predicted for the same molecule. Computational modeling of the influence of the inhomogeneous effective dielectric surrounding a substrate within the protein environment of an enzymic reaction requires an explicit treatment. The EIE (KH/KD) for transfer of cyclopentyl, cyclohexyl, tetrahydrofuranyl and tetrahydropyranyl cations from water to cyclohexane is predicted by B3LYP/6-31+G(d) calculations with implicit solvation and confirmed by B3LYP/6-31+G(d)/OPLS-AA calculations with averaging over many explicit solvation configurations. Atomic Hessian analysis, whereby the full Hessian is reduced to the elements belonging to a single atom at the site of isotopic substitution, reveals a remarkable result for both implicit and explicit solvation: the influence of the solvent environment on these EIEs is essentially captured completely by only a 3 × 3 block of the Hessian, although these values must correctly reflect the influence of the whole environment. QM/MM simulation with ensemble averaging has an important role to play in assisting the meaningful interpretation of observed isotope effects for chemical reactions both in solution and catalyzed by enzymes

    Spitzer IRS Spectra of Luminous 8 micron Sources in the Large Magellanic Cloud: Testing color-based classifications

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    We present archival Spitzer IRS spectra of 19 luminous 8 micron selected sources in the Large Magellanic Cloud (LMC). The object classes derived from these spectra and from an additional 24 spectra in the literature are compared with classifications based on 2MASS/MSX (J, H, K, and 8 micron) colors in order to test the "JHK8" classification scheme (Kastner et al. 2008). The IRS spectra confirm the classifications of 22 of the 31 sources that can be classified under the JHK8 system. The spectroscopic classification of 12 objects that were unclassifiable in the JHK8 scheme allow us to characterize regions of the color-color diagrams that previously lacked spectroscopic verification, enabling refinements to the JHK8 classification system. The results of these new classifications are consistent with previous results concerning the identification of the most infrared-luminous objects in the LMC. In particular, while the IRS spectra reveal several new examples of asymptotic giant branch (AGB) stars with O-rich envelopes, such objects are still far outnumbered by carbon stars (C-rich AGB stars). We show that Spitzer IRAC/MIPS color-color diagrams provide improved discrimination between red supergiants and oxygen-rich and carbon-rich asymptotic giant branch stars relative to those based on 2MASS/MSX colors. These diagrams will enable the most luminous IR sources in Local Group galaxies to be classified with high confidence based on their Spitzer colors. Such characterizations of stellar populations will continue to be possible during Spitzer's warm mission, through the use of IRAC [3.6]-[4.5] and 2MASS colors.Comment: 31 pages, 10 figures, to be published in A

    CHINESE CONSUMER DEMAND FOR ANIMAL PRODUCTS AND IMPLICATIONS FOR U.S. PORK AND POULTRY EXPORTS

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    This paper examines Chinese consumer preference for major animal products and assesses the potential impacts of a reduction in China's import tariff on its pork and poultry demand and net import. Our analysis suggests that China's demand for animal products will continue to grow as income increases. Using a trade model, results of our scenario analysis indicate that a reduction in China's import tariffs will significantly increase its net pork and poultry imports and the U.S. will capture most of the increases. Nevertheless, the impact on the market price in China and the U.S. is likely to be very small.Almost Ideal Demand System, China, Consumer demand, Demand elasticity, Food demand, Partial equilibrium model, Two-stage budgeting, U.S. meat export, Demand and Price Analysis, International Relations/Trade,

    Studies on the generative reproduction of grapevine powdery mildew (Uncinula necator BERK.)

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    Morphology and factors influencing the development of Uncinula necator fruit bodies were studied.The resistance levels of hostplants and the amount of cleistothecia on their leaves were significantly correlated under field conditions.The number of cleistothecia was about 80 % lower on greenhouse plants than on field-grown vines with similar susceptibility.An UV irradiation (2 h) did not induce the opening of the cleistothecia after cold storage, neither did light or darkness. A longer UV treatment (5 h), however, decreased the percentage of open cleistothecia.Liquid water was essential for the opening process. An atmosphere with a 100 % relative humidity was not sufficient.The fruit bodies opened readily at +22 °C, but not at +5 °C and below.Cleistothecia contained up to 6 asci with an average content of 6 ascospores. About 50 % of the ascospores had still their full vitality after 6-weeks cold storage

    Pressure distribution for the wing of the YAV-8B airplane; with and without pylons

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    Pressure distribution data have been obtained in flight at four span stations on the wing panel of the YAV-8B airplane. Data obtained for the supercritical profiled wing, with and without pylons installed, ranged from Mach 0.46 to 0.88. The altitude ranged from approximately 20,000 to 40,000 ft and the resultant Reynolds numbers varied from approximately 7.2 million to 28.7 million based on the mean aerodynamic chord. Pressure distribution data and flow visualization results show that the full-scale flight wing performance is compromised because the lower surface cusp region experiences flow separation for some important transonic flight conditions. This condition is aggravated when local shocks occur on the lower surface of the wing (mostly between 20 and 35 percent chord) when the pylons are installed for Mach 0.8 and above. There is evidence that convex fairings, which cover the pylon attachment flanges, cause these local shocks. Pressure coefficients significantly more negative than those for sonic flow also occur farther aft on the lower surface (near 60 percent chord) whether or not the pylons are installed for Mach numbers greater than or equal to 0.8. These negative pressure coefficient peaks and associated local shocks would be expected to cause increasing wave and separation drag at transonic Mach number increases

    Do Individual Differences And Aging Effects In The Estimation Of Geographical Slant Reflect Cognitive Or Perceptual Effects?

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    Several individual differences including age have been suggested to affect the perception of slant. A cross-sectional study of outdoor hill estimation (N = 106) was analyzed using individual difference measures of age, experiential knowledge, fitness, personality traits, and sex. Of particular note, it was found that for participants who reported any experiential knowledge about slant, estimates decreased (i.e., became more accurate) as conscientiousness increased, suggesting that more conscientious individuals were more deliberate about taking their experiential knowledge (rather than perception) into account. Effects of fitness were limited to those without experiential knowledge, suggesting that they, too, may be cognitive rather than perceptual. The observed effects of age, which tended to produce lower, more accurate estimates of hill slant, provide more evidence that older adults do not see hills as steeper. The main effect of age was to lower slant estimates; such effects may be due to implicit experiential knowledge acquired over a lifetime. The results indicate the impact of cognitive, rather than perceptual factors on individual differences in slant estimation

    Optimal psycholinguistic environments for distance foreign langauge learning

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    Rational choices among the numerous technological options available for foreign language teaching need to be based, in part, on psycholinguistic considerations. Which technological advances help create an optimal psycholinguistic environment for language learning, and which may be innovative but relatively unhelpful? One potential source of guidance is offered by the ten methodological principles of Task-Based Language Teaching (Long, 1985, and elsewhere), each realizable by a variety of pedagogic procedures. Interest in TBLT derives from several sources, including its responsiveness to learners’ precisely specified communicative needs, the potential it offers for developing functional language proficiency without sacrificing grammatical accuracy, and its attempt to harmonize the way languages are taught with what SLA research has revealed about how they are learned. TBLT’s ten methodological principles are briefly defined and motivated, and illustrations provided of how the principles can inform choices among technological options in the particular case of distance education for the less commonly taught languages

    Freedom of Association

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    To determine whether a limitation upon freedom of association by a state is constitutionally justified, the Court must balance the interests of those individuals whose rights have been restricted against the interests of the state involved. Constitutional freedoms guaranteed by the First Amendment may be restricted only when the state has a compelling interest. A state may take action in the interest of public safety, health, or welfare to prevent abuse of the exercise of these freedoms, but it may not curtail the rights themselves. Only the public interest or a clear and present danger would justify restriction of First Amendment freedoms. Confronted with the desirability of suppressing an organization, a governmental group may use one or more of the following approaches: (1) enforce criminal laws; (2) apply administrative and regulatory powers; (3) bring the pressure of public opinion against the group and its members
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