MODELING PRICE IMPACTS OF BACKWARD VERTICAL INTEGRATION IN THE US PORK INDUSTRY

The U.S. pork sector is evolving from an industry of small, independent firms vertically linked by spot markets to one of substantially larger firms vertically connected through contractual agreements and integration. Potential benefits to this tighter vertical arrangement include lower consumer pork prices, although the true nature of this benefit is still under debate. At the same time, there is concern of market foreclosure because highly vertically integrated industry may prevent independent hog producers from having access to open markets in which to sell their output. The objective of this paper is to develop an econometric model to estimate the extent of backward integration by pork processing firms into the upstream hog production stage, taking into account the oligopsonistic nature of the processors, and to simulate the effect of vertical integration on consumer and producer prices and welfare.backward vertical integration, oligopsony, pork, Industrial Organization, Livestock Production/Industries,

Minnesota Agricultural Economist 689

Livestock Production/Industries, Marketing,

Evidence That Cytochrome \u3cem\u3eb\u3csub\u3e5\u3c/sub\u3e\u3c/em\u3e Acts as a Redox Donor in CYP17A1 Mediated Androgen Synthesis

Cytochrome P450 17A1 (CYP17A1) is an important drug target for castration resistant prostate cancer. It is a bi-functional enzyme, catalyzing production of glucocorticoid precursors by hydroxylation of pregnene-nucleus, and androgen biosynthesis by a second C--C lyase step, at the expense of glucocorticoid production. Cytochrome b5(cyt b5) is known to be a key regulator of the androgen synthesis reaction in vivo, by a mechanism that is not well understood. Two hypotheses have been proposed for the mechanism by which cyt b5 increases androgen biosynthesis. Cyt b5 could act as an allosteric effector, binding to CYP17A1 and either changing its selective substrate affinity or altering the conformation of the P450 to increase the catalytic rate or decrease unproductive uncoupling channels. Alternatively, cyt b5 could act as a redox donor for supply of the second electron in the P450 cycle, reducing the oxyferrous complex to form the reactive peroxo-intermediate. To understand the mechanism of lyase enhancement by cyt b5, we generated a redox-inactive form of cyt b5, in which the heme is replaced with a Manganese-protoporphyrin IX (Mn-b5), and investigated enhancement of androgen producing lyase reaction by CYP17A1. Given the critical significance of a stable membrane anchor for all of the proteins involved and the need for controlled stoichiometric ratios, we employed the Nanodisc system for this study. The redox inactive form was observed to have no effect on the lyase reaction, while reactions with the normal heme-iron containing cyt b5 were enhanced ∼5 fold as compared to reactions in the absence of cyt b5. We also performed resonance Raman measurements on ferric CYP17A1 bound to Mn-b5. Upon addition of Mn-b5 to Nanodisc reconstituted CYP17A1, we observed clear evidence for the formation of a b5-CYP17A1 complex, as noted by changes in the porphyrin modes and alteration in the proximal Fe--S vibrational frequency. Thus, although Mn-b5 binds to CYP17A1, it is unable to enhance the lyase reaction, strongly suggesting that cyt b5 has a redox effector role in enhancement of the CYP17A1 mediated lyase reaction necessary for androgen synthesis

Supergravities with Minkowski x Sphere Vacua

Recently the authors have introduced a new gauged supergravity theory with a positive definite potential in D=6, obtained through a generalised Kaluza-Klein reduction from D=7. Of particular interest is the fact that this theory admits certain Minkowski x Sphere vacua. In this paper we extend the previous results by constructing gauged supergravities with positive definitive potentials in diverse dimensions, together with their vacuum solutions. In addition, we prove the supersymmetry of the generalised reduction ansatz. We obtain a supersymmetric solution with no form-field fluxes in the new gauged theory in D=9. This solution may be lifted to D=10, where it acquires an interpretation as a time-dependent supersymmetric cosmological solution supported purely by the dilaton. A further uplift to D=11 yields a solution describing a pp-wave.Comment: Latex, 26 pages, typos correcte

Black carbon physical and optical properties across northern India during pre-monsoon and monsoon seasons

Black carbon (BC) is known to have major impacts on both climate and human health and is therefore of global importance, particularly in regions close to large populations that have strong sources. The size-resolved mixing state of BC-containing particles was characterised using a single-particle soot photometer (SP2). The study focusses on the Indo-Gangetic Plain (IGP) during the pre-monsoon and monsoon seasons. Data presented are from the UK Facility for Airborne Atmospheric Measurements BAe-146 research aircraft that performed flights during the pre-monsoon (11 and 12 June) and monsoon (30 June to 11 July) seasons of 2016. Over the IGP, BC mass concentrations were greater (1.95 µg m−3) compared to north-west India (1.50 µg m−3) and north-east India (0.70 µg m−3) during the pre-monsoon season. Across northern India, two distinct BC modes were recorded; a mode of small BC particles (core diameter <0.16 µm and coating thickness <50 nm) and a mode of moderately coated BC (core diameter <0.22 µm and coating thickness of 50–200 nm). The IGP and north-east India locations exhibited moderately coated black carbon particles with enhanced coating thicknesses, core sizes, mass absorption cross sections, and scattering enhancement values compared to much lower values present in the north-west. The coating thickness and mass absorption cross section increased with altitude (13 %) compared to those in the boundary layer. As the monsoon arrived across the region, mass concentration of BC decreased over the central IGP and north-east locations (38 % and 28 % respectively), whereas for the north-west location BC properties remained relatively consistent. Post-monsoon onset, the coating thickness, core size, mass absorption cross section, and scattering enhancement values were all greatest over the central IGP much like the pre-monsoon season but were considerably reduced over both north-east and north-west India. Increases in mass absorption cross section through the atmospheric column were still present during the monsoon for the north-west and central IGP locations, but less so over the north-east due to lack of long-range transport aerosol aloft. Across the Indo-Gangetic Plain and north-east India during the pre-monsoon and monsoon seasons, solid-fuel (wood burning) emissions form the greatest proportion of BC with moderately coated particles. However, as the monsoon develops in the north-east there was a switch to small uncoated BC particles indicative of traffic emissions, but the solid-fuel emissions remained in the IGP into the monsoon. For both seasons in the north-west, traffic emissions form the greatest proportion of BC particles. Our findings will prove important for greater understanding of the BC physical and optical properties, with important consequences for the atmospheric radiative forcing of BC-containing particles. The findings will also help constrain the regional aerosol models for a variety of applications such as space-based remote sensing, chemistry transport modelling, air quality, and BC source and emission inventories

Development, characteristics, and effects of the new Chatham Harbor inlet

A new tidal inlet into Chatham Harbor, Massachusetts, has developed from a breach in the barrier beach, Nauset Beach, that forms the outer shoreline of southeastern Cape Cod. Increased tidal range and wave energy resulting from the new inlet produced acute coastal erosion and channel shoaling within Chatham Harbor, with significant impacts on the fishing and boating industries, and on private and public propeny and interests. Study results are consistent with the hypothesis that the Nauset-Monomoy barrier beach system undergoes a long-term cycle of geomorphological change, and that a new cycle was initiated with the formation of this new inlet. Based on this new understanding, future changes in the system can be foreseen and provided to coastal resource managers.Funding was provided by the Commonwealth of Massachusetts, Department of Environmental Management, Division of Waterways; the Town of Chatham; Woods Hole Sea Grant Program; Massachusetts Office of Coastal Zone Management; U.S. Army Corps of Engineers (New England Division and Coastal Engineering Research Center); Town of Orleans; and Friends of Pleasant Bay

Regulation-Structured Dynamic Metabolic Model Provides a Potential Mechanism for Delayed Enzyme Response in Denitrification Process

In a recent study of denitrification dynamics in hyporheic zone sediments, we observed a significant time lag (up to several days) in enzymatic response to the changes in substrate concentration. To explore an underlying mechanism and understand the interactive dynamics between enzymes and nutrients, we developed a trait-based model that associates a community’s traits with functional enzymes, instead of typically used species guilds (or functional guilds). This enzyme-based formulation allows to collectively describe biogeochemical functions of microbial communities without directly parameterizing the dynamics of species guilds, therefore being scalable to complex communities. As a key component of modeling, we accounted for microbial regulation occurring through transcriptional and translational processes, the dynamics of which was parameterized based on the temporal profiles of enzyme concentrations measured using a new signature peptide-based method. The simulation results using the resulting model showed several days of a time lag in enzymatic responses as observed in experiments. Further, the model showed that the delayed enzymatic reactions could be primarily controlled by transcriptional responses and that the dynamics of transcripts and enzymes are closely correlated. The developed model can serve as a useful tool for predicting biogeochemical processes in natural environments, either independently or through integration with hydrologic flow simulators

Regulation-Structured Dynamic Metabolic Model Provides a Potential Mechanism for Delayed Enzyme Response in Denitrification Process

In a recent study of denitrification dynamics in hyporheic zone sediments, we observed a significant time lag (up to several days) in enzymatic response to the changes in substrate concentration. To explore an underlying mechanism and understand the interactive dynamics between enzymes and nutrients, we developed a trait-based model that associates a community’s traits with functional enzymes, instead of typically used species guilds (or functional guilds). This enzyme-based formulation allows to collectively describe biogeochemical functions of microbial communities without directly parameterizing the dynamics of species guilds, therefore being scalable to complex communities. As a key component of modeling, we accounted for microbial regulation occurring through transcriptional and translational processes, the dynamics of which was parameterized based on the temporal profiles of enzyme concentrations measured using a new signature peptide-based method. The simulation results using the resulting model showed several days of a time lag in enzymatic responses as observed in experiments. Further, the model showed that the delayed enzymatic reactions could be primarily controlled by transcriptional responses and that the dynamics of transcripts and enzymes are closely correlated. The developed model can serve as a useful tool for predicting biogeochemical processes in natural environments, either independently or through integration with hydrologic flow simulators