PRACTICAL CHALLENGES TO ESTIMATING THE BENEFITS OF AGRICULTURAL R&D: THE CASE OF PLANT BREEDING RESEARCH

Interest in the economics of plant breeding first emerged during the late 1960s and early 1970s following the well-known green revolutions in wheat and rice. Since that time, few branches of agricultural research have been subjected to as much scrutiny as plant breeding. Impacts assessment studies consistently conclude that the economic benefits generated by successful plant breeding programs are large, positive, and widely distributed. Case studies repeatedly find that investment in crop genetic improvement generates attractive rates of return compared to alternative investment opportunities. Similarly, case studies consistently show that the welfare benefits resulting from the adoption of modern varieties (MVs) are broadly shared by producers and consumers in both favored and marginal environments. Swayed by the large body of empirical evidence that supports these findings, governments, lending agencies, philanthropic organizations, and private corporations have invested millions in plant breeding research. But how reliable are the results of studies that estimate the benefits of plant breeding research? Are the methods used to conduct such studies theoretically sound? And are the data sufficiently complete and accurate? This paper reviews methods used to estimate the benefits of plant breeding research and discusses methodological issues and practical challenges that often receive inadequate attention in applied impacts work. Our goal is not to question the validity of the broad conceptual frameworks used to estimate the benefits of plant breeding research (e.g., economic surplus approach, production function approach). Nor is it our intention to examine theoretical issues that complicate research evaluation in general. Rather, the objectives of the paper are to examine problems that may arise during empirical evaluation of plant breeding research, to discuss what can happen if those problems are ignored or overlooked, and to propose workable solutions. The problems that affect the empirical evaluation of plant breeding research can be grouped into three general categories: measuring the adoption of MVs; estimating the benefits associated with adoption of MVs; and assigning credit for plant breeding research. In principle, estimating the area planted to MVs should be relatively easy. In practice, it is often very difficult. Important issues in estimating the benefits associated with MV adoption include the relationship between experimental and farm level yields; the relative effects of improved germplasm and improved crop management practices; maintenance research; non-yield benefits; and constructing counterfactual scenarios. The existence of spillovers in plant breeding research increases the overall benefits generated by the global plant breeding system, but it also complicates the task of assigning credit among individual breeding programs. CIMMYT researchers, working in collaboration with colleagues from national agricultural research organizations, have conducted a series of studies designed to document and quantify the impacts of international maize and wheat breeding research. Drawing on lessons learned from the CIMMYT studies, each of these three sets of problems that can affect the empirical evaluation of plant breeding research are discussed in detail, and practical guidelines are presented to help those interested in conducting applied impacts studies avoid common pitfalls that if ignored may lead to incorrect empirical results.Research and Development/Tech Change/Emerging Technologies,

Factor Analysis Reveals Effects of Reducing Conditions on the Fate and Transport of RDX in Groundwater

Groundwater investigations conducted at the Massachusetts Military Reservation (MMR) show the impact of historic activities on the development of groundwater contaminant plumes emanating from military ranges. Several of the plumes, located on the southeastern side of the reservation, contain elevated concentrations of hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX). In most cases, these plumes show continuity from the source to the leading edge, indicating that very little attenuation of RDX is occurring in the aquifer. Interesting exceptions to this trend are locations where plumes consisting of RDX and perchlorate intercept part of the aquifer that was previously impacted by a fuel spill; reducing conditions due to biological activity resulted from this spill. RDX concentrations show a significant positive correlation with both dissolved oxygen and oxidation-reduction potential, and a significant negative correlation with specific conductivity. The distribution of RDX is more consistent upgradient from the oxygen depleted zone and implies that RDX is degrading in the aquifer near the fuel spill. A factor analysis yielded two geochemical (44 percent variability explained) and two contaminant (30 percent variability explained) factors. This suggests that the geochemical nature of the aquifer is the primary source of groundwater parameter variability determined by this investigation

A Geoarchaeological Investigation of the Rush Creek Site, Cannon County, Tennessee

Geoarchaeological investigations were used to assess the depositional and post-depositional processes that effected the Rush Creek Site (40CN79) in Cannon County, Tennessee. Of particular interest was a buried landform, found in the floodplain of the East Fork Stones River, that was sealed by sterile alluvium. This formation contained both prehistoric and historic artifacts within the same context. The stratigraphy of the site was determined by deep testing to describe the site and the landforms associated with the site. Samples collected from the exposed profiles of the deep test pits were subjected to particle size, pH, carbon, and phosphorus analyses. Statistical parameters derived from the particle size analysis were subjected to multivariate statistical procedures. Particle size and multivariate analyses demonstrate that variable landforms can be discriminated according to relative age due to the formation of pedogenically derived clay in older landforms, and increased sand content in younger landforms. Carbon and phosphorus analyses show human influence in the buried floodplain formation due to the substantial amount of each found in the midden in comparison to the surrounding landforms. Conflicting radiocarbon dates and historic period research in the area helped to demonstrate that a possible historic truncation episode was responsible for the deposition of historic artifacts within the archaeological context of those of aboriginal origin

Effects Of Reducing Conditions On The Fate And Transport Of RDX In Groundwater; A Multivariate Approach

Groundwater investigations conducted at the Massachusetts Military Reservation (MMR) show the impact of historic activities on the development of groundwater contaminant plumes emanating from military ranges. Several of the plumes, located on the southeastern side of the reservation, contain elevated concentrations of hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX). In most cases, these plumes show continuity from the source to the leading edge, indicating that very little attenuation of RDX is occurring in the aquifer. Interesting exceptions to this trend are locations where plumes consisting of RDX and perchlorate intercept part of the aquifer that was previously impacted by a fuel spill; reducing conditions due to biological activity resulted from this spill. RDX concentrations show a significant positive correlation with both dissolved oxygen and oxidation-reduction potential, and a significant negative correlation with specific conductivity. The distribution of RDX is more consistent upgradient from the oxygen depleted zone and implies that RDX is degrading in the aquifer near the fuel spill. A factor analysis yielded two geochemical (44 percent variability explained) and two contaminant (30 percent variability explained) factors. This suggests that the geochemical nature of the aquifer is the primary source of groundwater parameter variability determined by this investigation

Anomaly Detection in Paleoclimate Records using Permutation Entropy

Permutation entropy techniques can be useful in identifying anomalies in paleoclimate data records, including noise, outliers, and post-processing issues. We demonstrate this using weighted and unweighted permutation entropy of water-isotope records in a deep polar ice core. In one region of these isotope records, our previous calculations revealed an abrupt change in the complexity of the traces: specifically, in the amount of new information that appeared at every time step. We conjectured that this effect was due to noise introduced by an older laboratory instrument. In this paper, we validate that conjecture by re-analyzing a section of the ice core using a more-advanced version of the laboratory instrument. The anomalous noise levels are absent from the permutation entropy traces of the new data. In other sections of the core, we show that permutation entropy techniques can be used to identify anomalies in the raw data that are not associated with climatic or glaciological processes, but rather effects occurring during field work, laboratory analysis, or data post-processing. These examples make it clear that permutation entropy is a useful forensic tool for identifying sections of data that require targeted re-analysis---and can even be useful in guiding that analysis.Comment: 15 pages, 7 figure

Gastric plexiform fibromyxoma tumor in a child – Case report and review of the literature

AbstractPlexiform fibromyxoma tumor (PFT) is an exceedingly rare tumor, particularly in children where only four cases have been reported to date. The patient reported herein presented with abdominal pain and vomiting related to gastric outlet obstruction caused by a large, polypoid PFT. We describe the clinical features, diagnostic evaluation, and surgical treatment of this rare tumor in our patient. Further, we review the literature of FPT to bring attention to this rare gastric tumor to the Pediatric Surgeon

Mechanisms Regulating the Association of Protein Phosphatase 1 with Spinophilin and Neurabin

Protein phosphorylation is a key mediator of signal transduction, allowing for dynamic regulation of substrate activity. Whereas protein kinases obtain substrate specificity by targeting specific amino acid sequences, serine/threonine phosphatase catalytic subunits are much more promiscuous in their ability to dephosphorylate substrates. To obtain substrate specificity, serine/threonine phosphatases utilize targeting proteins to regulate phosphatase subcellular localization and catalytic activity. Spinophilin and its homologue neurabin are two of the most abundant dendritic spine-localized protein phosphatase 1 (PP1) targeting proteins. The association between spinophilin and PP1 is increased in the striatum of animal models of Parkinson's disease (PD). However, mechanisms that regulate the association of spinophilin and neurabin with PP1 are unclear. Here, we report that the association between spinophilin and PP1α or PP1γ1 was increased by CDK5 expression and activation in a heterologous cell system. This increased association is at least partially due to phosphorylation of PP1. Conversely, CDK5 expression and activation decreased the association of PP1 with neurabin. As with dopamine depletion, methamphetamine (METH) abuse causes persistent alterations in dopamine signaling which influence striatal medium spiny neuron function and biochemistry. Moreover, both METH toxicity and dopamine depletion are associated with deficits in motor control and motor learning. Pathologically, we observed a decreased association of spinophilin with PP1 in rat striatum evaluated one month following a binge METH paradigm. Behaviorally, we found that loss of spinophilin recapitulates rotarod pathology previously observed in dopamine-depleted and METH-treated animals. Together, these data have implications in multiple disease states associated with altered dopamine signaling such as PD and psychostimulant drug abuse and delineate a novel mechanism by which PP1 interactions with spinophilin and neurabin may be differentially regulated