An impact evaluation of technology adoption by smallholders in Sichuan, China: the case of sweet potato-pig systems

We employ propensity score matching (PSM) framework to examine the impact of sweet potato-based feed technology adoption on household-based pig production in Sichuan, China. An ex post survey in six villages was conducted in 2009, of which five villages were in project intervention sites (exposed area) and one village in the same township but not exposed to project intervention (non-exposed area). We randomly selected 111 households in the exposed areas from the list of households previously interviewed in a baseline survey and 53 households from non-exposed area. Matching estimators such as nearest neighbor matching (NNM), radius matching (RM) and kernel matching (KM) were used to estimate average treatment effects. Results indicate positive net benefit from adoption of sweet potato-based feeding technology, i.e., gross margin estimates of silage adopters are on average higher by 2-4 RMB per kg liveweight of output than non-adopters of similar characteristics. Silage adopters are also likely to produce 3-7 more slaughter pigs per year than non-adopters having similar characteristics, on average. Analysis of factors driving adoption indicates that sweet potato-based feed technology is not suitable in all smallholder context in Sichuan. Where this is suitable is in systems where sweet potato is an important crop, where there is limited access to input markets such as in upland or mountainous areas, where corn is not an important crop, and where households raise no more than 10 pigs given available household labor for pig raising in rural areas (generally either old people who are no longer active in the labor force, or young children who are still in school). Overall, the results show that sweet potato-based feed technology plays an important role in helping household-based pig producers become resilient, by having options in feeding strategies that help them cope with volatility in output prices (e.g., prices of live pigs as a function of retail prices of pork) and input prices (e.g., price of corn vis-à-vis price of pork, price of industrial feed). Exposure to the technology and its benefits through actual demonstration also appears to be more effective in engendering uptake and sustaining adoption.Technology adoption, impact assessment, crop-livestock systems, Livestock Production/Industries, Production Economics, O22, O33, Q16,

Generalized Matrix Decomposition Regression: Estimation and Inference for Two-way Structured Data

This paper studies high-dimensional regression with two-way structured data. To estimate the high-dimensional coefficient vector, we propose the generalized matrix decomposition regression (GMDR) to efficiently leverage any auxiliary information on row and column structures. The GMDR extends the principal component regression (PCR) to two-way structured data, but unlike PCR, the GMDR selects the components that are most predictive of the outcome, leading to more accurate prediction. For inference on regression coefficients of individual variables, we propose the generalized matrix decomposition inference (GMDI), a general high-dimensional inferential framework for a large family of estimators that include the proposed GMDR estimator. GMDI provides more flexibility for modeling relevant auxiliary row and column structures. As a result, GMDI does not require the true regression coefficients to be sparse; it also allows dependent and heteroscedastic observations. We study the theoretical properties of GMDI in terms of both the type-I error rate and power and demonstrate the effectiveness of GMDR and GMDI on simulation studies and an application to human microbiome data.Comment: 25 pages, 6 figures, Accepted by the Annals of Applied Statistic

Mapping susceptibility loci for alcohol consumption using number of grams of alcohol consumed per day as a phenotype measure

BACKGROUND: There is substantial evidence for a significant genetic component to the risk for alcoholism. However, susceptibility loci or genes for alcohol dependence remain largely unknown. To identify susceptibility loci for alcohol dependence, we selected 329 extended families from the Framingham Heart Study population in which at least one family member reported alcohol consumption during the interview in 1970–1971, and performed genome-wide linkage analyses using various analytical methods. RESULTS: Multi-point sib-pair regression analysis using the SIBPAL program of S.A.G.E. provided strong evidence for linkage of alcohol dependence to chromosomes 9 (p-value < 0.0001) and weak evidence to chromosomes 15 and 16 (p-value < 0.005). To confirm these findings, we re-analyzed the same data set by various methods implemented in GENEHUNTER and found that only one region was significant with a LOD score > 2.0 by the variance-component method. This region is located on chromosome 9 between markers GATA21F05 and GATA81C04. CONCLUSION: Analyses of the Framingham Heart Study population provided evidence of genetic susceptibility loci for alcohol dependence on chromosomes 9, 15, and 16. The genomic region identified on chromosome 9 was particularly interesting because the region has also been previously reported to be linked to alcohol dependence in the American Indian population by another group

Morphological population balance modelling of the effect of crystallisation environment on the evolution of crystal size and shape of para-aminobenzoic acid

A current morphological population balance (MPB) modelling methodology, which integrates crystal morphology, facet growth kinetics with multi-dimensional population balance, is overviewed and demonstrated, hence providing an attractive approach for modelling crystallisation processes. MPB modelling is applied to simulate the batch crystallisation of the alpha-form of para-aminobenzoic acid from ethanolic solutions as a function of the crystallisation environment including cooling rate, seeding temperature and seed conditions (loading, size and shape). The evolution of crystal shape/size and their distributions revealed that higher loading led to smaller and less needle-like crystals with similar yields, hence potentially being an important parameter for process control. Examination of the development of the fracture surface for broken seeds, mimicking the seed conditions after milling in practice in the simulated processes, demonstrated that these faces grew fast and then rapidly disappeared from the external crystal morphology. Restriction and challenges inherent in the current model are also highlighted

A genome-wide scan to identify loci for smoking rate in the Framingham Heart Study population

BACKGROUND: Although many years of genetic epidemiological studies have demonstrated that genetics plays a significant role in determining smoking behavior, little information is available on genomic loci or genes affecting nicotine dependence. Several susceptibility chromosomal regions for nicotine dependence have been reported, but few have received independent confirmation. To identify susceptibility loci for nicotine dependence, 313 extended pedigrees selected from the Framingham Heart Study population were analyzed by both the GENEHUNTER and S.A.G.E. programs. RESULTS: After performing linkage analyses on the 313 extended Framingham Heart Study families, the EM Haseman-Elston method implemented in GENEHUNTER provided evidence for significant linkage of smoking rate to chromosome 11 and suggestive linkage to chromosomes 9, 14, and 17. Multipoint sib-pair regression analysis using the SIBPAL program of S.A.G.E. on 1389 sib pairs that were split from the 313 extended families identified suggestive linkage of smoking rate to chromosomes 4, 7, and 17. Of these identified positive regions for nicotine dependence, loci on chromosomes 7, 11, and 17 were identified by both GENEHUNTER and S.A.G.E. programs. CONCLUSION: Our genome-wide scan results on the Framingham Heart Study data provide evidence for significant linkage of smoking rate to chromosome 11 and suggestive linkage to chromosomes 4, 7, 9, 14, and 17. These findings suggest that some of these regions may harbor susceptibility loci for nicotine dependence, and warrant further investigation in this and other populations

RAPID AND RELIABLE HEALING OF CRITICAL SIZE BONE DEFECTS WITH GENETICALLY MODIFIED SHEEP MUSCLE

Large segmental defects in bone fail to heal and remain a clinical problem. Muscle is highly osteogenic, and preliminary data suggest that autologous muscle tissue expressing bone morphogenetic protein-2 (BMP-2) efficiently heals critical size defects in rats. Translation into possible human clinical trials requires, inter alia, demonstration of efficacy in a large animal, such as the sheep. Scale-up is fraught with numerous biological, anatomical, mechanical and structural variables, which cannot be addressed systematically because of cost and other practical issues. For this reason, we developed a translational model enabling us to isolate the biological question of whether sheep muscle, transduced with adenovirus expressing BMP-2, could heal critical size defects in vivo. Initial experiments in athymic rats noted strong healing in only about one-third of animals because of unexpected immune responses to sheep antigens. For this reason, subsequent experiments were performed with Fischer rats under transient immunosuppression. Such experiments confirmed remarkably rapid and reliable healing of the defects in all rats, with bridging by 2 weeks and remodelling as early as 3-4 weeks, despite BMP-2 production only in nanogram quantities and persisting for only 1-3 weeks. By 8 weeks the healed defects contained well-organised new bone with advanced neo-cortication and abundant marrow. Bone mineral content and mechanical strength were close to normal values. These data demonstrate the utility of this model when adapting this technology for bone healing in sheep, as a prelude to human clinical trials

The estimated economic burden of genital herpes in the United States. An analysis using two costing approaches

BACKGROUND: Only limited data exist on the costs of genital herpes (GH) in the USA. We estimated the economic burden of GH in the USA using two different costing approaches. METHODS: The first approach was a cross-sectional survey of a sample of primary and secondary care physicians, analyzing health care resource utilization. The second approach was based on the analysis of a large administrative claims data set. Both approaches were used to generate the number of patients with symptomatic GH seeking medical treatment, the average medical expenditures and estimated national costs. Costs were valued from a societal and a third party payer's perspective in 1996 US dollars. RESULTS: In the cross-sectional study, based on an estimated 3.1 million symptomatic episodes per year in the USA, the annual direct medical costs were estimated at a maximum of $984 million. Of these costs, 49.7$214 million. The analysis of 1,565 GH cases from the claims database yielded a minimum national estimate of $283 million direct medical costs. CONCLUSIONS: GH appears to be an important public health problem from the health economic point of view. The observed difference in direct medical costs may be explained with the influence of compliance to treatment and possible undersampling of subpopulations in the claims data set. The present study demonstrates the validity of using different approaches in estimating the economic burden of a specific disease to the health care system

An impact evaluation of technology adoption by smallholders in Sichuan, China: The case of sweet potato-pig systems

We employ propensity score matching (PSM) framework to examine the impact of sweet potatobased feed technology adoption on household-based pig production in Sichuan, China. An ex post survey in six villages was conducted in 2009, of which five villages were in project intervention sites (exposed area) and one village in the same township but not exposed to project intervention (nonexposed area). We randomly selected 111 households in the exposed areas from the list of households previously interviewed in a baseline survey and 53 households from non-exposed area. Matching estimators such as nearest neighbor matching (NNM), radius matching (RM) and kernel matching (KM) were used to estimate average treatment effects. Results indicate positive net benefit from adoption of sweet potato-based feeding technology, i.e., gross margin estimates of silage adopters are on average higher by 2-4 RMB per kg liveweight of output than non-adopters of similar characteristics. Silage adopters are also likely to produce 3-7 more slaughter pigs per year than non-adopters having similar characteristics, on average. Analysis of factors driving adoption indicates that sweet potato-based feed technology is not suitable in all smallholder context in Sichuan. Where this is suitable is in systems where sweet potato is an important crop, where there is limited access to input markets such as in upland or mountainous areas, where corn is not an important crop, and where households raise no more than 10 pigs given available household labor for pig raising in rural areas (generally either old people who are no longer active in the labor force, or young children who are still in school). Overall, the results show that sweet potato-based feed technology plays an important role in helping household-based pig producers become resilient, by having options in feeding strategies that help them cope with volatility in output prices (e.g., prices of live pigs as a function of retail prices of pork) and input prices (e.g., price of corn vis-à-vis price of pork, price of industrial feed). Exposure to the technology and its benefits through actual demonstration also appears to be more effective in engendering uptake and sustaining adoption