1,269 research outputs found
Provisions and Potential Impacts of the Average Crop Revenue Election (ACRE) Program
Replaced with revised version of paper 11/24/08.Agricultural and Food Policy, Crop Production/Industries,
Estimates of Minnesota Farm-Level Crop Commodity Payments under New House Framework
The objective of this study is to compare commodity payments under current Federal farm policy with the previous Senate and Administration proposals and the recently released “2008 Farm Bill Conference: House Agriculture Committee-Developed Concept for a Farm Bill Spending Framework.” Projections of crop revenue and government payments are made using historical yield data for each example farm, the county, and the nation; historical price data; and statistical distributions and relationships of these yields and prices. Using 2007 FAPRI price projections (which are closer to the prices expected in the next few years when a new farm bill will be in force), expected Total Government Payments (TGP) are almost entirely attributed to the fixed direct payments under all these proposals. Since commodity prices are so far above their “target levels” the possibility of a counter cyclical price or revenue payment or a loan deficiency payment is highly unlikely. TGP under the alternative policies follows a similar pattern on the example corn and soybean farms and a slightly different but fairly consistent pattern for the example wheat and soybean farms. For the corn and soybean example farms in southern Minnesota, the HB-RCCP and USDA proposals generate very similar levels of TGPs compared to current policy. HB-RCCP provides a slightly higher expected TGP than CP for all example farms except for one and higher TGP than USDA for all farms. ACR is estimated to provide lower TGP for all example corn and soybean farms. For the example wheat and soybean farms in northwest Minnesota, the results are mixed. Compared to the other three proposals, ACR provides higher TGP for 2 of the 6 example farms. Each of the proposals does reduce risk as measured by CV. We note ACR is not quite as efficient at risk reduction except for two wheat/soybean farms in northwest Minnesota.Farm Management,
Alternative Farm Bills: Impacts on Minnesota Farms
With the current federal farm bill set to expire at the end of September this year, many proposals have been made to redesign the next bill. The objectives of this study are to compare the current policy with major proposed alternatives and estimate the potential payments of farmers under each of the alternatives. The alternative policies are compared in two ways. First a historical comparison of crop revenue and estimated government payments for individual farms are made under each proposal from 2002-2005. In a second comparison, projections of crop revenue and government payments are made using historical yields for each farm, county, and nation; historical price data; statistical distributions of the yields and prices including averages, standard deviations, and correlations; and each proposal's rules for calculating payments. For yields, deviations from the yield trend are used. In three of the four years and on average, the American Soybean Association (ASA) proposal has higher payments and thus higher total gross revenue compared to current policy and the other three proposals. Since the ASA proposal raises both loan rates and target prices, the higher payments should be expected. The proposed USDA policy is estimated to have a slightly higher average government payment and total gross revenue compared to current policy, but it is not higher than current policy in each year. Lower total payments under the National Corn Growers Association (NCGA) proposal are due to higher than average revenues during 2002-05. The revenue insurance proposal does not create any indemnity payments in 2002-05 again due to the higher revenues in these years. Projections of potential revenue also show the ASA proposal to have higher estimated payments. Average government payments are estimated to be slightly higher under current policy compared to USDA's and NCGA's proposals. Since federal budget concerns may not allow the higher payments under the ASA proposal, the choice between the USDA and NCGA proposal may hinge on the level of administrative costs which would appear to be lower with the USDA proposal since it is based on one national estimate of revenue versus many county and individual calculations under the NCGA proposal. The potential use of multi-commodity revenue insurance will hinge on either the ability to provide additional support in fixed direct payments and green payments and larger federal budget concerns.Agricultural and Food Policy,
Genomic signatures of parasite-driven natural selection in north European Atlantic salmon (Salmo salar)
Abstract Understanding the genomic basis of host-parasite adaptation is important for predicting the long-term viability of species and developing successful management practices. However, in wild populations, identifying specific signatures of parasite-driven selection often presents a challenge, as it is difficult to unravel the molecular signatures of selection driven by different, but correlated, environmental factors. Furthermore, separating parasite-mediated selection from similar signatures due to genetic drift and population history can also be difficult. Populations of Atlantic salmon (Salmo salar L.) from northern Europe have pronounced differences in their reactions to the parasitic flatworm Gyrodactylus salaris Malmberg 1957 and are therefore a good model to search for specific genomic regions underlying inter-population differences in pathogen response. We used a dense Atlantic salmon SNP array, along with extensive sampling of 43 salmon populations representing the two G. salaris response extremes (extreme susceptibility vs resistant), to screen the salmon genome for signatures of directional selection while attempting to separate the parasite effect from other factors. After combining the results from two independent genome scan analyses, 57 candidate genes potentially under positive selection were identified, out of which 50 were functionally annotated. This candidate gene set was shown to be functionally enriched for lymph node development, focal adhesion genes and anti-viral response, which suggests that the regulation of both innate and acquired immunity might be an important mechanism for salmon response to G. salaris. Overall, our results offer insights into the apparently complex genetic basis of pathogen susceptibility in salmon and highlight methodological challenges for separating the effects of various environmental factors.Peer reviewe
Footprints of directional selection in wild atlantic salmon populations: Evidence for parasite-driven evolution?
Mechanisms of host-parasite co-adaptation have long been of interest in evolutionary biology; however, determining the genetic basis of parasite resistance has been challenging. Current advances in genome technologies provide new opportunities for obtaining a genome-scale view of the action of parasite-driven natural selection in wild populations and thus facilitate the search for specific genomic regions underlying inter-population differences in pathogen response. European populations of Atlantic salmon (Salmo salar L.) exhibit natural variance in susceptibility levels to the ectoparasite Gyrodactylus salaris Malmberg 1957, ranging from resistance to extreme susceptibility, and are therefore a good model for studying the evolution of virulence and resistance. However, distinguishing the molecular signatures of genetic drift and environment-associated selection in small populations such as land-locked Atlantic salmon populations presents a challenge, specifically in the search for pathogen-driven selection. We used a novel genome-scan analysis approach that enabled us to i) identify signals of selection in salmon populations affected by varying levels of genetic drift and ii) separate potentially selected loci into the categories of pathogen (G. salaris)-driven selection and selection acting upon other environmental characteristics. A total of 4631 single nucleotide polymorphisms (SNPs) were screened in Atlantic salmon from 12 different northern European populations. We identified three genomic regions potentially affected by parasite-driven selection, as well as three regions presumably affected by salinity-driven directional selection. Functional annotation of candidate SNPs is consistent with the role of the detected genomic regions in immune defence and, implicitly, in osmoregulation. These results provide new insights into the genetic basis of pathogen susceptibility in Atlantic salmon and will enable future searches for the specific genes involved
Footprints of directional selection in wild atlantic salmon populations: Evidence for parasite-driven evolution?
Mechanisms of host-parasite co-adaptation have long been of interest in evolutionary biology; however, determining the genetic basis of parasite resistance has been challenging. Current advances in genome technologies provide new opportunities for obtaining a genome-scale view of the action of parasite-driven natural selection in wild populations and thus facilitate the search for specific genomic regions underlying inter-population differences in pathogen response. European populations of Atlantic salmon (Salmo salar L.) exhibit natural variance in susceptibility levels to the ectoparasite Gyrodactylus salaris Malmberg 1957, ranging from resistance to extreme susceptibility, and are therefore a good model for studying the evolution of virulence and resistance. However, distinguishing the molecular signatures of genetic drift and environment-associated selection in small populations such as land-locked Atlantic salmon populations presents a challenge, specifically in the search for pathogen-driven selection. We used a novel genome-scan analysis approach that enabled us to i) identify signals of selection in salmon populations affected by varying levels of genetic drift and ii) separate potentially selected loci into the categories of pathogen (G. salaris)-driven selection and selection acting upon other environmental characteristics. A total of 4631 single nucleotide polymorphisms (SNPs) were screened in Atlantic salmon from 12 different northern European populations. We identified three genomic regions potentially affected by parasite-driven selection, as well as three regions presumably affected by salinity-driven directional selection. Functional annotation of candidate SNPs is consistent with the role of the detected genomic regions in immune defence and, implicitly, in osmoregulation. These results provide new insights into the genetic basis of pathogen susceptibility in Atlantic salmon and will enable future searches for the specific genes involved
Frequency-Reconfigurable Dipole Antenna Using Liquid-Metal Pixels
A frequency-tunable half-wavelength dipole antenna is realized using an array of electrically actuated liquid-metal pixels. The liquid-metal pixelated dipole antenna demonstrates frequency reconfigurability by switching between resonances at 2.51 GHz, 2.12 GHz, 1.85 GHz, and 1.68 GHz
Aged Human Stored Red Blood Cell Supernatant Inhibits Macrophage Phagocytosis in an HMGB1 Dependent Manner After Trauma in a Murine Model:
Red blood cell transfusions in the setting of trauma is a double edged sword, as it is a necessary component for life-sustaining treatment in massive hemorrhagic shock, but also associated with increased risk for nosocomial infections and immune suppression. The mechanisms surrounding this immune suppression are unclear. Using supernatant from human packed red blood cell (RBC), we demonstrate that clearance of E. coli by macrophages is inhibited both in vitro and in vivo using a murine model of trauma and hemorrhagic shock. We further explore the mechanism of this inhibition by demonstrating that human stored RBCs contain soluble high mobility group box 1 protein (HMGB1) which increases throughout storage. HMGB1 derived from the supernatant of human stored RBCs was shown to inhibit bacterial clearance, as neutralizing antibodies to HMGB1 restored the ability of macrophages to clear bacteria. These findings demonstrate that extracellular HMGB1 within stored RBCs could be one factor leading to immune suppression following transfusion in the trauma setting
Commencement Program, August (1966)
https://red.mnstate.edu/commencement/1105/thumbnail.jp
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