334 research outputs found

    BEEF CATTLE GRAZING PREFERENCE OF TALL FESCUE AS AFFECTED BY ENDOPHYTE

    Get PDF
    Many factors control, contribute to, stimulate and limit forage selection. It is apparent that cattle prefer certain cultivars compared to others. This study sought to test if cattle displayed preferences for certain cultivars over a two-year period in 2008 and 2009. Determining the effect of endophyte status on preference was another objective. Previous research showed rapid increase in the selection of preferred cultivars, i.e., diet learning. We attempted to replicate those results. Forty cultivars (34 tall fescue (Lolium arundinaceum (Schreb.) Darbysh.) cultivars), two festuloliums (Festuca pratensis x Lolium perenne), two meadow fescue (Lolium pratense) and one meadow brome (Bromus biebersteinii), and one orchard grass (Dactylis glomerta L.)) were used to determine preference and to investigate factors contributing to preference. From this two-year study, we observed that cattle preferred certain cultivars compared to others, e.g. KYFA9819 \u3e Latar-OG \u3e Barfest-FL and AU-Triumph \u3c 97TF1-EF \u3c Seine, the most and least preferred cultivars, respectively. During drought conditions, both novel and toxic endophyte cultivars were preferred significantly (P \u3c 0.05) to endophyte free counterparts. The cattle showed rejection of unpalatable grasses but did not clearly show learning to increase selection of desired cultivars

    ANGIOTENSIN II INDUCTION OF REGIONAL EFFECTS IN MURINE VASCULATURE

    Get PDF
    The renin angiotensin system (RAS) exerts many diverse physiological functions throughout the body, mediated by its effector peptide, angiotensin II (AngII). AngII has been linked with a variety of different functions ranging from the initiation of severe vascular pathologies, such as atherosclerosis and abdominal aortic aneurysm (AAA), to mundane physiological processes of fluid homeostasis, vascular contraction, and regulation of blood pressure. To provide a potential link between these functions, an in-depth analysis of regional effects of AngII on aortic vasculature was performed. The studies presented in this dissertation tested the overall hypothesis of whether regional changes exist in the vasculature in response to angiotensin II (AngII). We first infused AngII into C57BL/6 animals and studied the aortic morphology in detail. On first glance, we detected a thickening throughout the aorta, with no overt changes from region to region. However, upon further analysis, it was demonstrated that there was a region-specific aortic arch hyperplasia, versus the hypertrophy in the remainder of the aorta. Through a series of experiments, this hyperplasia was linked to the redox-mediated protein Id3. Further analysis of the vasculature demonstrated AngII exerted aortic contractions which were limited to the infrarenal aorta. These contractions were mediated by the AT1b receptor subtype in the RAS. We also demonstrate that AngII leads to suprarenal specific formation of AAA, which can be attenuated by the deletion of specific innate immune mediator proteins, such as MyD88 and TLR4. Overall, these data suggest many region-specific roles for AngII in the aortic vasculature and provide many novel findings as to the cause of these effects

    Tailoring a ConOps for NASA LSP Integrated Operations

    Get PDF
    An integral part of the Systems Engineering process is the creation of a Concept of Operations (ConOps) for a given system, with the ConOps initially established early in the system design process and evolved as the system definition and design matures. As Integration Engineers in NASA's Launch Services Program (LSP) at Kennedy Space Center (KSC), our job is to manage the interface requirements for all the robotic space missions that come to our Program for a Launch Service. LSP procures and manages a launch service from one of our many commercial Launch Vehicle Contractors (LVCs) and these commercial companies are then responsible for developing the Interface Control Document (ICD), the verification of the requirements in that document, and all the services pertaining to integrating the spacecraft and launching it into orbit. However, one of the systems engineering tools that have not been employed within LSP to date is a Concept of Operations. The goal of this paper is to research the format and content that goes into these various aerospace industry ConOps and tailor the format and content into template form, so the template may be used as an engineering tool for spacecraft integration with future LSP procured launch services. This tailoring effort was performed as the authors final Masters Project in the Spring of 2016 for the Stevens Institute of Technology and modified for publication with INCOSE (Owens, 2016)

    Energy-efficient, Flow-specific Medium Access using Preamble Sampling

    Get PDF
    Current wireless sensor network applications face challenging power constraints that demand low duty cycles. In this paper, we propose an energy-efficient, flow-specific medium access scheme that is capable of achieving low duty cycles while taking advantage of the performance improvements available through a flow-specific medium access approach. The scheme is based on an adaptive sleep and wake cycle that responds to changes in both contention and non-contention traffic loads through the use of preamble sampling. A preamble sampling probability parameter is introduced to manage the trade-off between energy efficiency and network throughput and delay performance. A performance analysis is conducted and verified through simulation

    Dive into terahertz technology

    Get PDF
    Oklahoma Louis Stokes Alliance for Minority Participation ProgramElectrical and Computer Engineerin

    A Process for Capturing the Art of Systems Engineering

    Get PDF
    There is both an art and a science to systems engineering. The science of systems engineering is effectively captured in processes and procedures, but the art is much more elusive. We propose that there is six step process that can be applied to any systems engineering organization to create an environment from which the "art" of that organization can be captured, be allowed to evolve collaboratively and be shared with all members of the organization. This paper details this process as it was applied to NASA Launch Services Program (LSP) Integration Engineering Branch during a pilot program of Confluence, a Commercial Off The Shelf (COTS) wiki tool

    Housing Externalities

    Get PDF
    Using data compiled from concentrated residential urban revitalization programs implemented in Richmond, VA, between 1999 and 2004, we study residential externalities. Specifically, we provide evidence that in neighborhoods targeted by the programs, sites that did not directly benefit from capital improvements nevertheless experienced considerable increases in land value relative to similar sites in a control neighborhood. Within the targeted neighborhoods, increases in land value are consistent with externalities that fall exponentially with distance. In particular, we estimate that housing externalities decrease by half approximately every 990 feet. On average, land prices in neighborhoods targeted for revitalization rose by 2 to 5 percent at an annual rate above those in the control neighborhood. These increases translate into land value gains of between 2and2 and 6 per dollar invested in the program over a six-year period. We provide a simple theory that helps us interpret and estimate these effects.

    A Pilot Study to Determine MBSE Utility for Process Modeling of Complex Interfaces

    Get PDF
    Modeling a full system or a complete interface between systems in a MBSE environment is a very large task and not all organizations will benefit enough from using MBSE to offset the effort that is required to do this. Completely modeling a system or interface is not necessary to evaluate the utility of MBSE for a specific application or organization. A small pilot can be executed over a short period of time that only models small portions of a system or interface and, if structured properly, this pilot can successfully demonstrate the utility of MBSE for an organization before having to invest a larger amount of resources to fully implement and deploy MBSE. This paper documents one such pilot that was conducted for NASAs Launch Services Program

    A Pilot Study to Determine MBSE Utility for Process Modeling of Complex Interfaces

    Get PDF
    Modeling a full system or a complete interface between systems in a MBSE environment is a very large task and not all organizations will benefit enough from using MBSE to offset the effort that is required to do this. Completely modeling a system or interface is not necessary to evaluate the utility of MBSE for a specific application or organization. A small pilot can be executed over a short period of time that only models small portions of a system or interface and, if structured properly, this pilot can successfully demonstrate the utility of MBSE for an organization before having to invest a larger amount of resources to fully implement and deploy MBSE. This paper documents one such pilot that was conducted for NASA's Launch Services Program
    • …
    corecore