AN ECONOMIC ANALYSIS OF PASTURE-RAISED BEEF SYSTEMS IN APPALACHIA

Cow-calf operations are important enterprises for family farmers in Appalachia and provide significant opportunity for supplemental income. This analysis constitutes a thorough economic assessment of pasture-raised beef production, an alternative to traditional production that could benefit the region's producers in terms of profitability and mitigated risk. Stochastic budgeting was utilized for profitability and risk comparison between traditional and pasture-raised operations and accounted for seasonal variability in prices, pasture availability and animal performance. Pasture-raised systems, in relation to traditional ones, were shown to consistently yield higher returns over variable costs and were shown less likely to yield losses over total costs in typical production seasons. Economic risk for pasture-raised producers stems largely from production factors but, overall, is seemingly less pronounced than the market risk faced by traditional producers selling live cattle.Farm Management,

Absorption of gamma-emitting fission products and activation products by rice under flooded and unflooded conditions from two tropical soils

The absorption of gamma-emitting fission products 106Ru,125Sb,137Cs and144Ce and activation products59Fe,58Co.54Mn and65Zn by rice plants grown on two contrasting tropical soils, namely, a blak soil (pellustert) and a laterite (oxisol), and the effects of flooding were studied under controlled conditions. Results indicated greater uptake of 106Ru and 125Sb from the black soil than from the laterite. In contrast, the uptake of 144Ce and 137Cs was greater in the laterite than in the black soil. Flooding treatment enhanced the uptake of all these fission products by rice plants in the laterite soil whereas this effect was observed only for 125Sb and 137Cs in the black soil. The plant uptake of activation products from the two soil types showed maximum accumulation of 65Zn followed by 54Mn,59Fe and 58Co in both soil types. Besides, uptake of these nuclides was greater from the laterite soil than from the black soil. Flooding treatment for rice while showing a reduction of 59Fe uptake, showed an increase in plant uptake of 58Co,54Mn and 65Zn in both soil types

Rac regulates integrin-mediated spreading and increased adhesion of T lymphocytes

Leukocyte adhesion to the extracellular matrix (ECM) is tightly controlled and is vital for the immune response. Circulating lymphocytes leave the bloodstream and adhere to ECM components at sites of inflammation and lymphoid tissues. Mechanisms for regulating T-lymphocyte-ECM adhesion include (i) an alteration in the affinity of cell surface integrin receptors for their extracellular ligands and (ii) an alteration of events following postreceptor occupancy (e.g., cell spreading). Whereas H-Ras and R-Ras were previously shown to affect T-cell adhesion by altering the affinity state of the integrin receptors, no signaling molecule has been identified for the second mechanism. In this study, we demonstrated that expression of an activated mutant of Rac triggered dramatic spreading of T cells and their increased adhesion on immobilized fibronectin in an integrin-dependent manner. This effect was not mimicked by expression of activated mutant forms of Rho, Cdc42, H-Ras, of ARF6, indicating the unique role of pac in this event. The Rac-induced spreading was accompanied by specific cytoskeletal rearrangements; Also, a clustering of integrins at sites of cell adhesion and at the peripheral edges of spread cells was observed. We demonstrate that expression of RacV12 did not alter the level of expression of cell surface integrins or the affinity state of the integrin receptors. Moreover, our results indicate that Rac plays a role in the regulation of T-cell adhesion by a mechanism involving cell spreading, rather than by altering the level of expression or the affinity of the integrin receptors. Furthermore, we show that the Rac-mediated signaling pathway leading to spreading of T lymphocytes did not require activation of c-Jun kinase, serum response factor, or pp70(S6) (kinase) but appeared to involve a phospholipid kinase

Robust Bain distortion in the premartensite phase of platinum substituted Ni2MnGa magnetic shape memory alloy

The premartensite phase of shape memory and magnetic shape memory alloys (MSMAs) is believed to be a precursor state of the martensite phase with preserved austenite phase symmetry. The thermodynamic stability of the premartensite phase and its relation to the martensitic phase is still an unresolved issue, even though it is critical to the understanding of the functional properties of MSMAs. We present here unambiguous evidence for macroscopic symmetry breaking leading to robust Bain distortion in the premartensite phase of 10% Pt substituted Ni2MnGa. We show that the robust Bain distorted premartensite (T2) phase results from another premartensite (T1) phase with preserved cubic-like symmetry through an isostructural phase transition. The T2 phase finally transforms to the martensite phase with additional Bain distortion on further cooling. Our results demonstrate that the premartensite phase should not be considered as a precursor state with the preserved symmetry of the cubic austenite phase

Amphiphilic diblock copolymers as functional surfaces for protein chromatography

Stationary phase plays a crucial role in the operation of a protein chromatography column. Conventional resins composed of acrylic polymers and their derivatives contribute to heterogeneity of the packing of stationary phase inside these columns. Alternative polymer combinations through customized surface functionalization schemes which consist of multiple steps using static coating techniques are well known. In comparison, it is hypothesized that a single-step scheme is sufficient to obtain porous adsorbents as stationary phase for tuning surface morphology and protein immobilization. To overcome the challenge of heterogeneous packing and ease of fabrication at a laboratory scale, a change in the form factor of separation materials has been proposed in the form of functional copolymer surfaces. In the present work, an amphiphilic, block copolymer, poly(methyl methacrylate-co-methacrylic acid) has been chosen and fully characterized for its potential usage in protein chromatography. Hydrophilicity of the acrylic copolymer and abundance of carboxyl groups inherently on the copolymer surface have been successfully demonstrated through contact angle measurements, Fourier transform infrared (FTIR) and X-ray photoelectron spectroscopy (XPS) studies. Morphological studies indicate presence of a microporous region (nearly 1 to 1.5 $\mu$m pore size) that could be beneficial as a cation exchange media as part of the stationary phase in protein chromatography.Comment: 10 figures, submitted to Journa

Pterodactyl: Thermal Protection System for Integrated Control Design of a Mechanically Deployed Entry Vehicle

The need for precision landing of high mass payloads on Mars and the return of sensitive samples from other planetary bodies to specific locations on Earth is driving the development of an innovative NASA technology referred to as the Deployable Entry Vehicle (DEV). A DEV has the potential to deliver an equivalent science payload with a stowed diameter 3 to 4 times smaller than a traditional rigid capsule configuration. However, the DEV design does not easily lend itself to traditional methods of directional control. The NASA Space Technology Mission Directorate (STMD)s Pterodactyl project is currently investigating the effectiveness of three different Guidance and Control (G&C) systems actuated flaps, Center of Gravity (CG) or mass movement, and Reaction Control System (RCS) for use with a DEV using the Adaptable, Deployable, Entry, and Placement Technology (ADEPT) design. This paper details the Thermal Protection System (TPS) design and associated mass estimation efforts for each of the G&C systems. TPS is needed for the nose cap of the DEV and the flaps of the actuated flap control system. The development of a TPS selection, sizing, and mass estimation method designed to deal with the varying requirements for the G&C options throughout the trajectory is presented. The paper discusses the methods used to i) obtain heating environments throughout the trajectory with respect to the chosen control system and resulting geometry; ii) determine a suitable TPS material; iii) produce TPS thickness estimations; and, iv) determine the final TPS mass estimation based on TPS thickness, vehicle control system, vehicle structure, and vehicle payload

Unified framework for hybrid percolation transitions based on microscopic dynamics

A hybrid percolation transition (HPT) exhibits both discontinuity of the order parameter and critical behavior at the transition point. Such dynamic transitions can occur in two ways: by cluster pruning with suppression of loop formation of cut links or by cluster merging with suppression of the creation of large clusters. While the microscopic mechanism of the former is understood in detail, a similar framework is missing for the latter. By studying two distinct cluster merging models, we uncover the universal mechanism of the features of HPT-s at a microscopic level. We find that these features occur in three steps: (i) medium-sized clusters accumulate due to the suppression rule hindering the growth of large clusters, (ii) those medium size clusters eventually merge and a giant cluster increases rapidly, and (iii) the suppression effect becomes obsolete and the kinetics is governed by the Erd\H{o}s-R\'enyi type of dynamics. We show that during the second and third period, the growth of the largest component must proceed in the form of a Devil's staircase. We characterize the critical behavior by two sets of exponents associated with the order parameter and cluster size distribution, which are related to each other by a scaling relation. Extensive numerical simulations are carried out to support the theory where a specific method is applied for finite-size scaling analysis to enable handling the large fluctuations of the transition point. Our results provide a unified theoretical framework for the HPT.Comment: 15 pages, 14 figures, 4 table