26,178 research outputs found
Transaction Costs and Cattle Farmers' Choice of Marketing Channels in North-Central Namibia
About 70% of the Namibian population depends on agricultural activities for their livelihood. Moreover, agriculture remains an important sector to Namibia because its national economy is widely dependent on agricultural production. Cattle producers in the Northern Communal Areas (NCAs) have an option to market their cattle via the formal or informal markets. Efforts have been made to encourage producers to market their cattle through the formal market; however, limited improvement has been observed. In this study a number of factors have been analysed to determine its influences on cattle marketing decisions. Factors influencing the marketing decision of whether or not to sell through the formal market are analysed using the Probit model. Factors influencing the proportion of cattle sold through the formal market on condition that a producer uses the formal markets to sell cattle are analysed with the Truncated model. Testing the Tobit model against the alternative of a two-part model is done using Cragg’s model. Empirical results revealed that problems with transport to MeatCo, improved productivity, accessibility to market-related information and access to new information technology, are some factors significantly affecting the decision of whether or not to sell through the formal market. Payment arrangements by MeatCo, animal handling, accessibility to new information technology, age of respondents and lack of access to marketing expertise, are some factors influencing the proportional number of cattle sold through the formal market. The results suggest that substantially more information is obtained by modelling cattle marketing behaviour as a two decision-making instead of a single decision-making framework.Cattle marketing, decision-making, formal markets, transaction costs, Livestock Production/Industries,
Compatibility of Glyphosate with Galerucella calmariensis; a Biological Control Agent for Purple Loosestrife (Lythrum salicaria)
By integrating Galerucella calmariensis with glyphosate there is potential to achieve both immediate and sustained control of purple loosestrife (Lythrum salicaria). The objective of this study was to determine the compatibility of glyphosate on the oviposition and survival of adult G. Calmariensis and on the ability of G. calmariensis third instar larvae to pupate to teneral adults. Our results revealed glyphosate (formulated as Roundup) at a concentration of 2% (2.43L/acre) and 4% solution (4.86 L/acre) had no impact on the ability of G. calmariensis third instar larvae to pupate to new generation adults. To examine the effect of a 2% solution of glyphosate on adult G. calmariensis oviposition and survival, adults were randomly divided between a direct contact group (adults sprayed directly), an indirect contact group (host plants with adults were sprayed), and a control group. Our results revealed that glyphosate does not impact G. calmariensis oviposition or adult survival. The results of this study indicate that G. calmariensis is compatible with glyphosate indicating that further field studies examining integrated control strategies for purple loosestrife are warranted
Quality assessment of two- and three-dimensional unstructured meshes and validation of an upwind Euler flow solver
Quality assessment procedures are described for two-dimensional and three-dimensional unstructured meshes. The procedures include measurement of minimum angles, element aspect ratios, stretching, and element skewness. Meshes about the ONERA M6 wing and the Boeing 747 transport configuration are generated using an advancing front method grid generation package of programs. Solutions of Euler's equations for these meshes are obtained at low angle-of-attack, transonic conditions. Results for these cases, obtained as part of a validation study demonstrate the accuracy of an implicit upwind Euler solution algorithm
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Membrane-Mediated Alterations of Intracellular Na+ and K+ in Lytic-Virus-Infected and Retrovirus-Transformed Cells
Infection of chick-embryo fibroblasts and other ceils by certain animal viruses results in alterations in the intracellular concentrations of Na + and K +. Dramatic alterations in monovalent-cation concentrations of lytic-virus-infected ceils may favor the synthesis of viral proteins over cellular proteins. More subtle alterations in retrovirus-transformed cells may result in the expression of many morphological and biochemical changes associated with the transformed phenotype.Public Health Service Grant CA 26169, CA 27003National Cancer Institute CA 06593Integrative Biolog
Schwarzchild Black Holes in Matrix Theory II
We present a crude Matrix Theory model for Schwarzchild black holes in
uncompactified dimension greater than . The model accounts for the size,
entropy, and long range state interactions of black holes. The key feature of
the model is a Boltzmann gas of D0 branes, a concept which depends on certain
qualitative features of Matrix Theory which have not previously been utilized
in studies of black holes.Comment: 20 pages,harvmac,big, Some Typos corrected, 1 reference adde
Regional variation in digital cushion pressure in the forefeet of horses and elephants
In this study, we seek to understand how the digital cushion morphologies evident in horse and elephant feet influence internal and external foot pressures. Our novel use of invasive blood pressure monitoring equipment, combined with a pressure pad and force plate, enabled measurements of (ex vivo) digital cushion pressure under increasing axial loads in seven horse and six elephant forefeet. Linear mixed effects models (LMER) revealed that internal digital cushion pressures increase under load and differ depending on region; elephant feet experienced higher magnitudes of medial digital cushion pressure, whereas horse feet experienced higher magnitudes of centralised digital cushion pressure. Direct comparison of digital cushion pressure magnitudes in both species, at equivalent loads relative to body weight, revealed that medial and lateral pressures increased more rapidly with load in elephant limbs. Within the same approximate region, internal pressures exceeded external, palmar pressures (on the sole of the foot), supporting previous Finite Element (FE) predictions. High pressures and large variations in pressure may relate to the development of foot pathology, which is a major concern in horses and elephants in a captive/domestic environment
Quantum Monte Carlo method using phase-free random walks with Slater determinants
We develop a quantum Monte Carlo method for many fermions that allows the use
of any one-particle basis. It projects out the ground state by random walks in
the space of Slater determinants. An approximate approach is formulated to
control the phase problem with a trial wave function . Using
plane-wave basis and non-local pseudopotentials, we apply the method to Si
atom, dimer, and 2, 16, 54 atom (216 electrons) bulk supercells. Single Slater
determinant wave functions from density functional theory calculations were
used as with no additional optimization. The calculated binding
energy of Si2 and cohesive energy of bulk Si are in excellent agreement with
experiments and are comparable to the best existing theoretical results.Comment: 5 pages, Latex, with 1 fi
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