9,151 research outputs found
Farm size and nonparametric efficiency measurements for coffee farms in Vietnam
We study the efficiency of smallholder coffee farms in Vietnam. Data from a 2004 survey of farms in two districts in Dak Lak Province are used in a two-step analysis. In the first step, technical and cost efficiency measures are calculated using DEA. In the second step, Tobit regressions are used to identify factors correlated with technical and cost inefficiency. Results indicate that small farms were less efficient than large farms. Inefficiencies observed on small farms appear to be related, in part, to the scale of investments in irrigation infrastructure.Farm Management,
Systematic Development of Trans-Theoretically Based Behavioral Risk Management Programs
The authors explain the development and use of a behavioral Risk management strategy. It is designed for developing interventions to change behaviors, e.g., to lower the Risk of AIDS. The advantage of their strategy is said to be its structure combined with flexibility. Intervenors are not restricted to a single model in determining factors most relevant to changing Risky behavior
Linkages between Market Participation and Productivity: Results from a Multi-Country Farm Household Sample
We build upon international trade literature to analyze the direction of causality between market participation and productivity. Cross-country household data from Tanzania, Vietnam and Guatemala are used in a 2SLS approach with market participation and productivity as endogenous variables. Results indicate that households with higher productivity tend to participate in agricultural markets regardless of market access factors. In contrast, having better market access does not necessarily lead to higher productivity. This finding suggests that investments in market access infrastructure provide minimal, if any, improvements in agricultural productivity; whereas programs targeted at enhancements in farm structure and capital have the potential to increase both productivity and market participation.International Relations/Trade, Marketing, Productivity Analysis,
Agricultural Prices and Income Distribution among Farmers: A Whole-Household, Multi-Country, Multi-Year Analysis
Recent studies have emphasized that the poorest farmers are often net buyers of key commodities and therefore harmed by rising prices. We use LSMS data from Tanzania, Vietnam and Guatemala to test the degree of net purchases or sales by income level. We find that poorer farmers may be net buyers of individual crops, but only the poorest are net buyers of all crops. More generally, net sales among poor farmers are low. We conclude that agricultural price changes have a diverse but limited influence on poor farmers’ welfare, because their farm sales tend to be offset by food purchases.market participation, poverty, inequality, multi-continent multicountry, Agricultural Finance,
Invariant manifolds and equilibrium states for non-uniformly hyperbolic horseshoes
In this paper we consider horseshoes containing an orbit of homoclinic
tangency accumulated by periodic points. We prove a version of the Invariant
Manifolds Theorem, construct finite Markov partitions and use them to prove the
existence and uniqueness of equilibrium states associated to H\"older
continuous potentials.Comment: 33 pages, 6 figure
Genetic Improvement of Bermudagrass for Hay Producers
Bermudagrass (Cynodon spp.) is considered the most valuable warm-season perennial grass for hay producers in the Southeastern United States. Bermudagrass genotypes have overall good forage quality, high yields, and store well. However, there are challenges to producing good hay for the market. First, early green-up in the spring is needed to allow for four to five productive clippings during the summer. When first establishing production fields, quick emergence and cover are important for reducing weeds. Forage bermudagrass is somewhat tolerant to drought, however, low rainfall substantially reduces yields. If rainfall is too abundant, it is difficult to have timely curing in the field for baling. This is especially true for the higher quality thick-stemmed cultivars such as Tifton 85. More recently, the bermudagrass stem maggot (BSM, Atherigona reversura) has caused yield reductions and reduced net income for hay producers. Plant breeding has attempted to address all these issues. This talk will highlight some areas of research that has been done over the past few decades to improve bermudagrass for hay production
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Global Gene Expression Analysis Identifies Age-Related Differences in Knee Joint Transcriptome during the Development of Post-Traumatic Osteoarthritis in Mice.
Aging and injury are two major risk factors for osteoarthritis (OA). Yet, very little is known about how aging and injury interact and contribute to OA pathogenesis. In the present study, we examined age- and injury-related molecular changes in mouse knee joints that could contribute to OA. Using RNA-seq, first we profiled the knee joint transcriptome of 10-week-old, 62-week-old, and 95-week-old mice and found that the expression of several inflammatory-response related genes increased as a result of aging, whereas the expression of several genes involved in cartilage metabolism decreased with age. To determine how aging impacts post-traumatic arthritis (PTOA) development, the right knee joints of 10-week-old and 62-week-old mice were injured using a non-invasive tibial compression injury model and injury-induced structural and molecular changes were assessed. At six-week post-injury, 62-week-old mice displayed significantly more cartilage degeneration and osteophyte formation compared with young mice. Although both age groups elicited similar transcriptional responses to injury, 62-week-old mice had higher activation of inflammatory cytokines than 10-week-old mice, whereas cartilage/bone metabolism genes had higher expression in 10-week-old mice, suggesting that the differential expression of these genes might contribute to the differences in PTOA severity observed between these age groups
Genetic Characterization of Prairie Grass (\u3cem\u3eBromus Catharticus\u3c/em\u3e Vahl.) Natural Populations
Prairie grass, Bromus catharticus Vahl., is a winter annual or biennial grass, native of South America which is widely distributed in the Pampeana area of Argentina and also cultivated in temperate regions of the world. Morphophysiological traits are currently used to assess the variability from natural populations and cultivars of this species. Molecular markers, which are not influenced by the environment, allow a more accurate assessment of genetic variability. Previous results from our group (Puecher et al., 2001a) showed a narrow genetic basis for the prairie grass cultivars used in Argentina. On the other hand, we also observed that natural populations of this species collected in the typical area where prairie grass is cultivated in Argentina, showed a RAPD variability pattern similar to that previously observed for cultivars (Puecher et al., 2001b). The objective of this work was to establish, using RAPDs, the genetic relationships among prairie grass natural populations including accessions from the margins of the cultivation area of this species in Argentina
Kinetics and thermodynamics of adsorption of red dye 40 from acidic aqueous solutions onto a novel chitosan sulfate
The kinetic and thermodynamics of adsorption of Red Dye 40 from acidic aqueous solutions onto a partially sulfated chitosan (ChS) was studied. The partially sulfated ChS was water insoluble in the pH range of 2-12. Experiments were carried out batch wise to determine the effect of pH, dye concentration, and temperature on the adsorption capacity of ChStowards Red Dye 40. It was found that the equilibrium dye-binding capacity of ChS (qe) increased with increasing initial dye concentration; however, the percentage of dye removal decreased. Dye adsorption capacity of ChS increased when the solution pH was reduced. The Langmuir model was better fitted the experimental adsorption equilibrium data, and therate of dye adsorption onto ChS follows the pseudosecond order kinetic model. The adsorption capacity of ChS was enhanced by increasing the temperature.The thermodynamic adsorption parameters, enthalpy(ΔH°), entropy (ΔS°), and Gibbs energy (ΔG°) were evaluated. The adsorption process was endothermic, and the Gibbs energy negative indicating that it occurred spontaneously
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