2,471 research outputs found
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,
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
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
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
Resources for Evidence-Based Health Care: Accessibility and Availability
Evidence – Based Practice (EBP) is a problem solving approach to clinical care that incorporates the conscientious use of current best evidence from well-designed studies, clinician’s expertise, and patient values and preferences (Melnyk & Fineout-Overholt, 2005; Sackett, Straus, Richardson, Rosenberg, &Haynes, 2000). It is important to see clinical expertise as the ability to integrate research evidence and patients' circumstances and preferences to help patients arrive at optimal decisions (Guyatt, Cook,& Haynes, 2004). Research has shown that patient outcomes are 28% better when clinical care is based upon evidence, versus clinical practice steeped in tradition (Heater, Becker, & Olsen, 1998). The process of EBP minimizes the translation time needed for incorporating research findings into practice and clarifies the differences between ritualistic practice, habitual approaches, personal preferences, anecdotal experiences, empirical data, and statistical significance to support nursing practice (Alspach, 2006). The availability of evidence based practice tools and methods helps in faster identification of the best available evidence to provide care at the point it matters most.
Implementing EBP in health care is complex and challenging. One of the main components of EBP is retrieving evidence from different sources. Information explosion with thousands of health literature and research papers published every year has created a need to expand the knowledge base for providing evidence based health care worldwide. Retrieval of evidence from various sources may be difficult due to several reasons. It may be difficult for health professionals to find the best available evidence due to time constraints (Ervin, 2002) or lack of knowledge among health professionals to effectively search for evidence (Sitzia, 2002). It is even difficult to find authentic sources of evidence
Pterodactyl: Trade Study for an Integrated Control System Design of a Mechanically Deployable Entry Vehicle
This paper presents the trade study method used to evaluate and downselect from a set of guidance and control (G&C) system designs for a mechanically Deployable Entry Vehicle (DEV). The Pterodactyl project was prompted by the challenge to develop an effective G&C system for a vehicle without a backshell, which is the case for DEVs. For the DEV, the project assumed a specific aeroshell geometry pertaining to an Adaptable, Deployable Entry and Placement Technology (ADEPT) vehicle, which was successfully developed by NASAs Space Technology Mission Directorate (STMD) prior to this study. The Pterodactyl project designed three different entry G&C systems for precision targeting. This paper details the Figures of Merit (FOMs) and metrics used during the course of the projects G&C system assessment. The relative importance of the FOMs was determined from the Analytic Hierarchy Process (AHP), which was used to develop weights that were combined with quantitative design metrics and engineering judgement to rank the G&C systems against one another. This systematic method takes into consideration the projects input while simultaneously reducing unintentional judgement bias and ultimately was used to select a single G&C design for the project to pursue in the next design phase
Towards the drivers of value creation in the biogas industry:enablers and inhibiters in the Netherlands
The Dutch biogas industry is developing slowly and in many instances still unviable. Insights in the drivers of value creation may help to create viable biogas business networks. This research explores these related drivers and accordingly, proposes a new and comprehensive definition of a driver of value creation. This definition focuses on the enabling and inhibiting factors of value creation in a business network and forms the backbone of three case studies. The results suggest the presence of four specific drivers as necessary for a viable biogas business network: stability and certainty, partner alignment, local opportunities and economies of scale
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