1,572 research outputs found

    Anisotropy of Imbalanced Alfvenic Turbulence in Fast Solar Wind

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    We present the first measurement of the scale-dependent power anisotropy of Elsasser variables in imbalanced fast solar wind turbulence. The dominant Elsasser mode is isotropic at lower spacecraft frequencies but becomes increasingly anisotropic at higher frequencies. The sub-dominant mode is anisotropic throughout, but in a scale-independent way (at higher frequencies). There are two distinct subranges exhibiting different scalings within what is normally considered the inertial range. The low Alfven ratio and shallow scaling of the sub-dominant Elsasser mode suggest an interpretation of the observed discrepancy between the velocity and magnetic field scalings. The total energy is dominated by the latter. These results do not appear to be fully explained by any of the current theories of incompressible imbalanced MHD turbulence.Comment: 5 pages, 2 figure

    The Weights of Young African Children in a Township in Rhodesia

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    A CAJM article on the standard weight of Zimbabwean (Rhodesian) children vis-a-vis the avarage incomes of their parents.No standards of normal weight for young children exist for the African population in Rhodesia. Ford (1964) suggested that the Havard Standards (Stuart and Stevenson, 1959) could be used as a guide in assessing malnutrition in different ethnic groups when no local standards of reference are available. This idea has been further elaborated by Jelliffe (1966), who suggested a General Standard of Reference, which was derived from the Havard data. This study establishes a standard for African children in Rhodesia and also compares the weight-for-age curve of these young children of mixed genetic background with that derived from the Havard data

    Modified Contactor for Experimental Studies of Mass Transfer and Chemical Reaction Across a Liquid-Liquid Interface

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    A Modified Stirred-Cell Type Contactor Has Been Designed and Tested for its Use in Experimental Investigations of Mass Transfer and Chemical Reaction in Liquid-Liquid Systems. its Design overcomes the Shortcomings of Previously Proposed Contactors. It is Easy to Operate and Has the Ability to Investigate the Effect of a Wide Range of Operating Conditions. the Mixing Performance of the Contactor Was Tested using a Dye Injection and a Tracer Technique. Experiments to Evaluate Mass-Transfer Coefficients Across a Liquid-Liquid Interface Have Been Conducted to Determine its Effectiveness. the Results Verified that the Contactor Could Be Successfully Employed as a Useful Experimental Research Apparatus

    Rwanda\u27s Miracle: From Genocide and Poverty to Peace and Economic Prosperity

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    The purpose of this thesis was to examine how liberalization and the introduction of pro-poor policies can be successful in post-conflict countries using the Rwanda coffee market as a case study. My research supports the notion that economic development, political stability and peace can be a result of liberalization when policies that are pro-poor and focus on the largest sector of the population are created. The study examines why and how Rwanda chose to liberalize their economy in the way they did by focusing on the intentions of the actors and the effects their actions have had on the coffee market and country as a whole. The findings suggest that Rwanda’s coffee market liberalization has been successful and has contributed to stability and economic development in Rwanda. The conclusion indicates that pro-poor liberalization policies with the assistance from a variety of actors and institutions can lead developing countries on the path to development in ways the international community has not seen before

    An Experimental Overview of Results Presented at SQM 2006

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    I have been asked to give an critical overview on the experimental results shown in the conference with a emphasis of what has been learned and the challenges that are ahead in trying to understand the physics of the strongly interacting quark-gluon plasma. I will not try to summarize all of the results presented, rather I will concentrate primarily on RHIC data from this conference. Throughout this summary, I will periodically review some of the previous results for those not familiar with the present state of the field.Comment: 15 pages, 12 Figure

    Evaluating the Agronomic Feasibility of Planting late Season Corn for Feedlot Cattle

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    Yield, Ib/acre, bushel weight (BD), Ib/bu, relative maturity (RELMAT), chemical composition and in vitro dry matter digestibility (IVDMD) were used to screen corn varieties In = 20) of varying maturities grown under the stress of a shortened growing season. Corn varieties were planted in late June of 1996. Whole shell corn (WSC) and ear corn (EC) were harvested. Bushel weight was quantified on WSC. Yields for WSC, and EC were 1941 + 706 and 2307 ± 997 Ib DM/acre, respectively. Whole shell corn and EC were sorted into yield (YGP) groups. Whole shell corn yields were 2942 ± 248, 2305 ± 138, and 1292 ± 343 Ib DM/acre for YGPI through YGP3, respectively. The EC yields were 3740 ± 207, 2980 ± 208, 1897 ± 235 and 1139 ± 455 Ib DM1 acre for YGP 1 through 4, respectively. For WSC, YGP 1, YGP 2 and YGP 3 produced 2529, 1956 and 1099 Ib TDN/ac, respectively. Ear corn YGP 1, YGP 2, YGP 3 and YGP 4 produced 2980, 2180, 1437 and 780 Ib of TDN/ac, respectively. Increased yield in corn varieties grown under the stress of a shortened growing season was attributed to an increase in starch content. Even so, digestibility and energy content were not related (P \u3e .05) to yield or BD. Relative maturity did not influence (P \u3e .05) chemical composition, digestibility or energy content. Results suggest that while selecting earlier maturing corn for short growing seasons improves yields, it gives no advantage to feed value. Bushel weight, yield or maturity date should not be used as single criteria when predicting feed value of corn grown under the stress of a shortened growing season

    Anisotropy of Solar Wind Turbulence between Ion and Electron Scales

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    The anisotropy of turbulence in the fast solar wind, between the ion and electron gyroscales, is directly observed using a multispacecraft analysis technique. Second order structure functions are calculated at different angles to the local magnetic field, for magnetic fluctuations both perpendicular and parallel to the mean field. In both components, the structure function value at large angles to the field S_perp is greater than at small angles S_par: in the perpendicular component S_perp/S_par = 5 +- 1 and in the parallel component S_perp/S_par > 3, implying spatially anisotropic fluctuations, k_perp > k_par. The spectral index of the perpendicular component is -2.6 at large angles and -3 at small angles, in broad agreement with critically balanced whistler and kinetic Alfven wave predictions. For the parallel component, however, it is shallower than -1.9, which is considerably less steep than predicted for a kinetic Alfven wave cascade.Comment: 4 pages, 4 figures, replaced to match published versio

    A Generalized Diffusion Tensor for Fully Anisotropic Diffusion of Energetic Particles in the Heliospheric Magnetic Field

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    The spatial diffusion of cosmic rays in turbulent magnetic fields can, in the most general case, be fully anisotropic, i.e. one has to distinguish three diffusion axes in a local, field-aligned frame. We reexamine the transformation for the diffusion tensor from this local to a global frame, in which the Parker transport equation for energetic particles is usually formulated and solved. Particularly, we generalize the transformation formulas to allow for an explicit choice of two principal local perpendicular diffusion axes. This generalization includes the 'traditional' diffusion tensor in the special case of isotropic perpendicular diffusion. For the local frame, we motivate the choice of the Frenet-Serret trihedron which is related to the intrinsic magnetic field geometry. We directly compare the old and the new tensor elements for two heliospheric magnetic field configurations, namely the hybrid Fisk and the Parker field. Subsequently, we examine the significance of the different formulations for the diffusion tensor in a standard 3D model for the modulation of galactic protons. For this we utilize a numerical code to evaluate a system of stochastic differential equations equivalent to the Parker transport equation and present the resulting modulated spectra. The computed differential fluxes based on the new tensor formulation deviate from those obtained with the 'traditional' one (only valid for isotropic perpendicular diffusion) by up to 60% for energies below a few hundred MeV depending on heliocentric distance.Comment: 8 pages, 6 figures, accepted in Ap
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