Die Rolle von Kommunikationskanälen für die Nahrungsmittelproduktion und die Wohlfahrt der Haushalte: Empirische Evidenz aus Nord-Ghana

Lack of information on innovative agricultural technologies continue to be a major constrain and cause of low technology adoption and productivity among farmers in sub-Saharan Africa. The emergence of new communication channels such as ICTs offer some prospects to boost agricultural extension delivery and lower the barriers to information diffusion among farmers. However, not much is known about the impact of the new communication channels on food production and welfare via its role in improving farmers’ technology adoption. This study in chapter two contributes to literature by employing copula functions, to examine the impact of participation in ICT-based extension channels on improved technology adoption, specifically the new Rhizobia inoculant technology, and its impact on farmers’ technical knowledge, yields and farm net returns. Low technology adoption persist among smallholder farmers in developing countries. This has been attributed to lack of understanding about the adoption decision-making behavior of farmers, leading to inability to develop appropriate extension policies that can enhance technology adoption. In chapter three, this study contributes to knowledge by employing dynamic treatment effect model to analyze farmers’ adoption decision-making as a dynamic process, one that comprises a series of multiple decisions made over several stages or periods. The inability to develop appropriate extension policies has also been attributed to the disconnection between empirical studies that examine adoption of technological packages and studies that analyze management practices of those packages. Chapter four of this study attempts to bridge the knowledge gap by employing the stochastic frontier treatment effect with endogenous mediator model to simultaneously estimate the impact of technology adoption and extension participation and decompose their interaction effect into direct and indirect effects. The use of farmers’ egocentric information or social networks to diffusion information about new technologies leading to adoption is voluminous in the literature. However, the impact of the egocentric information networks on the technical efficiency of farmers appears to be over looked in the literature. This study in chapter five contributes to literature by employing spatial stochastic frontier analysis to investigate the impact of egocentric information networks on farmers’ technical efficiency, productivity and its distributive mechanisms among farmers in the network. The findings in chapter two reveal that ICT-based extension channels are equally effective as the conventional extension channels, and in some instances, outperform them. The study found that ICT extension channels lead to higher yields, farm net returns, and knowledge gained, relative to conventional extension channels and non-participation in extension programs. The study in chapter three further reveal the existence of significant impact heterogeneities across different adoption stages, with the long-term benefits of adoption outweighing the short-term benefits. The study found that there exist unrealized potential gains at some stages in the adoption process, in particular, at knowledge acquisition and trial stages, which extension policymakers can target in order to maximize adoption impacts and save resources to expand extension outreach to benefit more farmers. Chapter four of the results show that the direct impact of technology adoption alone contributes 72% to farm productivity and 73% indirectly due to improvement in farmers’ efficiency, leading to overall welfare improvement of 77%. Similarly, the direct impact of extension participation alone contributes 28% to farm productivity and 27% indirectly due to improvement in farmers’ efficiency, resulting in 23% improvement in farmers’ welfare. The findings suggest that, it is insufficient and less beneficial to provide extension services to farmers without the provision of improved technology. Finally, the study in chapter five reveal that 19% of farmers’ technical inefficiency depend on the inefficiency of the farmers from whom they seek farming advice. The results also show that inefficient farmers tend to depend on efficient farmers in their egocentric information networks to improve their level of efficiency. In general, the study provides empirical evidence to inform effective extension service delivery policies, towards attainment of the Sustainable Development Goals (SDGs), in particular goal two and five, which seek to achieve zero hunger and equal access to extension services by all for enhance agricultural productivity

Reciprocal expression of interferon gamma or interleukin 4 during the resolution or progression of murine leishmaniasis. Evidence for expansion of distinct helper T cell subsets.

We purified poly(A)+ mRNA from the spleen and lymph nodes at designated times after infection with Leishmania major in genetically susceptible BALB/c and resistant C57BL/6 mice. The steady-state levels of IL-2, IFN-gamma, IL-4, and IL-1 beta mRNA were determined using Northern hybridizations. IL-2 mRNA levels in the infected organs of BALB/c and C57BL/6 mice were comparable after infection, but IFN-gamma and IL-4 mRNA levels were reciprocally expressed. Levels of IFN-gamma mRNA in C57BL/6 draining nodes and spleen were significantly greater than in BALB/c mice except at 4 and 6 wk of infection, when splenic IFN-gamma mRNA levels were transiently comparable. In contrast, IL-4 mRNA was apparent only in BALB/c and not in C57BL/6 nodes and spleen. Tissue levels of IL-1 beta mRNA were 10-20-fold greater in BALB/c mice. BALB/c mice were pretreated with GK1.5 mAb, a manipulation that promotes healing of subsequent infection by transiently depleting L3T4+ cells. At 8 wk of infection, by which time lymphoid organs were repopulated with L3T4+ cells, GK1.5-pretreated BALB/c mice produced IFN-gamma, but not IL-4 message. Serum levels of IgE were markedly elevated in infected BALB/c, but not in infected C57BL/6 or GK1.5-pretreated BALB/c mice, consistent with in vivo biologic activity of IL-4 in nonhealing mice. Treatment of infected BALB/c mice with neutralizing anti-IL-4 antibody abolished the elevation of serum IgE and significantly attenuated the progression of disease as assessed by size and ulceration of the lesion, and by reduction in the number of tissue parasites. Both protective and deleterious responses to Leishmania infection have previously been shown to be L3T4+ cell dependent. Our findings are consistent with the differential expansion of protective, IFN-gamma-producing Th1 cells in healing mice, and the expansion of deleterious, IL-4-producing Th2 cells in nonhealing mice. The inverse relationship of IFN-gamma and IL-4 gene expression during leishmaniasis may underlie the divergence of cellular and humoral immunity that occurs during chronic infection with Leishmania and possibly other intracellular parasites

Cure of murine leishmaniasis with anti-interleukin 4 monoclonal antibody. Evidence for a T cell-dependent, interferon gamma-independent mechanism.

BALB/c mice infected with Leishmania major develop fatal, progressive disease, despite an immune response characterized by expansion of CD4+ T cells in the draining lymph nodes. The immune response has been further characterized by a lack of IFN-gamma mRNA, but increased IL-4 mRNA in lymphoid tissues, and striking elevation of serum IgE. Treatment of infected BALB/c mice with rIFN-gamma at doses shown to be beneficial in other protozoan infections was insufficient to ameliorate L. major infection. In contrast, neutralization of IL-4 by six weekly injections of mAb 11B11 led to attenuation of disease in 100% of animals, and complete cure in 85%. Resolution of disease required the presence of T cells, and recovered mice remained resistant to reinfection at 12 wk. This immunity was adoptively transferable and was dependent on both CD4+ and CD8+ cells. Although administration of anti-IL-4 was associated with fourfold increase in IFN-gamma mRNA in lymph node cells draining the lesion, the coadministration of neutralizing R4 6A2 anti-IFN-gamma mAb had no effect on resistance to disease. This was in marked contrast to resolution of disease in both resistant C57BL/6- and GK1.5-pretreated BALB/c mice that was abrogated by in vivo treatment with anti-IFN-gamma. These data suggest a novel mechanism of cellular immunity established by interference with the development of Th2 cells during infection

Impacts of extension dissemination and technology adoption on farmers' efficiency and welfare in Ghana: Evidence from legume inoculant technology

Examining the welfare impact of agricultural development interventions that incorporate diffusion of improved production technologies to farmers within extension delivery programs can be very challenging, because of the difficulty in disentangling the individual impacts of the production technology and the extension delivery program. Using recent farm level survey data from extension dissemination program of legume inoculant technology of 600 farmers in Ghana, we employ a recent methodological approach to investigate, simultaneously, the impact of the inoculant technology adoption and the extension program participation on farmers' productivity, efficiency and welfare. We decompose each of these impact measures into subcomponents whose causal paths can be traced to both the adoption of the production technology and the extension delivery program. We find that, in terms of yields and net revenue, direct contribution of improved technology adoption alone is 34 and 64%, respectively, and 35 and 66% indirectly due to improved farmer efficiency, leading to 36 and 74% improvement in farmers' welfare, respectively. On the other hand, direct contribution of extension delivery program participation alone is 66 and 36%, respectively, with 66 and 34% indirectly due to improved farmer efficiency, resulting in 64 and 26% improvement in farmers' welfare, respectively. Based on the findings, we recommend that policymakers should invest in research and development to produce yield enhancing agricultural technologies suitable for poor and degraded soil conditions in developing countries which can contribute immensely to poverty and food insecurity reduction. The development of new agricultural technologies must be pursued with vigorous provision of extension services to farmers to be able to exploit the full potentials of the new technologies

Multi-product versus single-product timber rotation : comparative by regression and computer simulation

The study was done in cooperation with staff and assigned personnel of the Division of Land and Forest Resources, TVA, utilizing the simulation power of the agency\u27s WRAP program. WRAP is an acronym for Woodland Resource Analysis Program. The major purposes of the study were: 1. To develop regression models to examine multi-product versus single-product timber rotations through the financial-optimization procedures of WRAP. 2. To develop regression models to determine the relationship among the financial inputs to WRAP and the income stream generated in WRAP output. The study had four stages: 1) The generation of individual - stand simulated data through WRAP analysis for natural stands of loblolly pine (Pinus taeda L.); 2) Model building - i.e., definitions of independent and dependent variables and the form of the equations; 3) Regression analysis using both forward and backward stepwise procedures; and 4) Sensitivity testing of the regression equations including graphic illustrations to predict optimum rotations and present worths by different variables. Twelve separate equations were found by regression analysis using both forward and backward stepwise programs of the SAS package. Effective interest rate was the most important independent model variable in predicting either optimum rotation or present worth. Relative prices of sawtimber versus pulpwood were also very important under the assumptions of the study. The optimum rotation equations provided by this study varied from 18 to 55 years and should allow users to predict in advance the single product versus multi-product rotations which will be in the WRAP output. This knowledge should allow a better assignment of silvicultural treatments by the user. Price breaks among current product prices were also found for different optimum rotations

Dust-tolerant electrical connector

A connector assembly includes releasably mateable plug and receptacle units. At least one socket is enclosed within the receptacle unit and is aligned with at least one permeable membrane disposed in the front end of the receptacle unit. The plug unit includes a body slidably mounted within a longitudinal bore therein. At least one pin extends from the front end of the body and is aligned with at least one permeable membrane disposed in the front end of the plug unit. The plug unit is biased toward a first, de-mate position in which the body is extended rearwardly such that the pin is enclosed with the plug unit and is slidable to a second, mate position in which the body is compressed forwardly such that the pin projects through the permeable membranes of the plug and receptacle units to electrically connect with the socket

Contract farming and the adoption of sustainable farm practices: Empirical evidence from cashew farmers in Ghana

Contract farming has been shown to increase agricultural productivity and thus welfare of farmers in developing countries. However, studies that look at the potential environmental effects of contract farming remain quite scanty. This is however crucial, since contract farming may contribute to intensification in cultivation of the contracted crops, in terms of area and the intensity of inputs used. This study investigates the impact of participation in contract farming on sustainable farm practices, using a marginal treatment effects (MTEs) approach to account for potential selection bias and heterogeneity across households. The empirical results show significant heterogeneity in the effects of contract farming on the intensity of sustainable farm practice use. In particular, farmers with high propensity to participate in contract farming tend to have low probabilities of using sustainable farm practices. The findings of this study not only provide new insights into the heterogeneous effects of contract farming, but also entry points for further research to address the dual challenge of agriculture to produce sufficient food, while reducing the adverse impact on the environment

EFFECT OF MATURITY STAGE AND STORAGE DURATION ON PHYSICO-CHEMICAL PROPERTIES OF CITRUS (CITRUS SINESIS VAR. LATE VALENCIA)

This study investigated the effect of maturity stage and duration of storage on physico-chemical properties of citrus fruits (Citrus sinensis var. late Valencia) in the Ashanti region of Ghana. A total of 450 mature fruits were harvested from the same farm for three different months, harvesting 150 fruits each month. Each harvest was categorised into three base on stage of maturity namely; mature green (MG), half ripe (HR) and full ripe (FR) fruits. A random sample of 50 fruits from the three categories were analysed on day one of harvest for their physico-chemical properties while the remaining 100 fruits were stored at ambient temperature (between 25C0 to 30C0) for 5 and 10 days before their physico-chemical properties were analysed. The physico-chemical properties measured were weight, juice yield, firmness, pH, vitamin C, TSS, sugar, TDS, TTA and EC. Some of the major findings of the study were that TTA in FR fruits were lower than that of MG and HR fruits at day five and ten of storage.Vitamin C content in MG, HR and FR fruits increased as storage duration increases to day five and ten under ambient temperature. Holding of MG and HR fruits for up to ten days increased the juice yield during processing compared to holding FR fruits. The study recommended that processors of natural orange juice should monitor closely the maturity stage of fruits they procure and the length of time fruits are stored before processing as product quality could be compromised or enhanced by these factors

EFFECT OF MATURITY STAGE AND STORAGE DURATION ON PHYSICO-CHEMICAL PROPERTIES OF CITRUS (CITRUS SINESIS VAR. LATE VALENCIA)

This study investigated the effect of maturity stage and duration of storage on physico-chemical properties of citrus fruits (Citrus sinensis var. late Valencia) in the Ashanti region of Ghana. A total of 450 mature fruits were harvested from the same farm for three different months, harvesting 150 fruits each month. Each harvest was categorised into three base on stage of maturity namely; mature green (MG), half ripe (HR) and full ripe (FR) fruits. A random sample of 50 fruits from the three categories were analysed on day one of harvest for their physico-chemical properties while the remaining 100 fruits were stored at ambient temperature (between 25C0 to 30C0) for 5 and 10 days before their physico-chemical properties were analysed. The physico-chemical properties measured were weight, juice yield, firmness, pH, vitamin C, TSS, sugar, TDS, TTA and EC. Some of the major findings of the study were that TTA in FR fruits were lower than that of MG and HR fruits at day five and ten of storage.Vitamin C content in MG, HR and FR fruits increased as storage duration increases to day five and ten under ambient temperature. Holding of MG and HR fruits for up to ten days increased the juice yield during processing compared to holding FR fruits. The study recommended that processors of natural orange juice should monitor closely the maturity stage of fruits they procure and the length of time fruits are stored before processing as product quality could be compromised or enhanced by these factors