1,768 research outputs found

    Nutritional Immunomodulation as an Approach to Decreasing the Negative Effects of Stress in Poultry Production

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    Stress can lead to changes in the immune response resulting in both increased and decreased resistance to opportunistic bacterial pathogens. Growth-promoting antibiotics have been a major tool in modulating hostpathogen interactions and limiting clinical and subclinical bacterial infection in confined animal production. Regulatory pressures to limit antibiotic use in poultry production and recent international marketing agreements that prohibit treating poultry with antibiotics have limited the disease-fighting tools available to poultry and livestock producers, particularly in Europe. There is a need to evaluate potential antibiotic alternatives to improve both production and disease resistance in high-intensity food animal production. Nutritional approaches to counteract the debilitating effects of stress and infection may provide producers with useful alternatives to antibiotics. Improving disease resistance in food animals, particularly in the absence of antibiotic treatment, is a key strategy in the effort to increase food safety. ARS research has demonstrated the efficacy of several nutritional immunomodulators, including vitamin D3 and yeast cell wall products, to protect against bacterial infection due to stress and challenge with opportunistic pathogens. These studies also provide an animal model for testing the efficacy of nutritional strategies that may affect the response to stress and related infection in humans

    Critical Evaluation of Bacteriophage to Prevent and Treat Colibacillosis in Poultry

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    There is a continuing need to find alternatives to antibiotics in animal and human medicine. Bacteriophages are viruses that infect and kill bacteria, with no known activity to plant and animal cells. We have conducted research to critically evaluate the efficacy of bacteriophage to both prevent and treat colibacillosis in poultry. Bacteriophages lytic to an Escherichia coli pathogenic to poultry were isolated from municipal waste water treatment plants and poultry processing plants. Two bacteriophage isolates were selected to use in studies designed to determine the efficacy of these bacteriophage to prevent and treat severe colibacillosis in poultry. Colibacillosis was induced by injecting 6 X 104 cfu of E. coli into the thoracic airsac when the birds were 1 week of age. Initial studies demonstrated that mortality was significantly reduced when the challenge culture was mixed with bacteriophage prior to challenging the birds. In subsequent studies, we have shown that an aerosol spray of bacteriophage given to the birds prior to this E. coli challenge can prevent the disease, and that an intramuscular injection of bacteriophage provides an effective treatment of this disease. We have demonstrated that bacteriophage can be used to both prevent and treat colibacillosis in poultry and may provide an effective alternative to antibiotic use in animal and human medicine

    Organizational learning and emotion: constructing collective meaning in support of strategic themes

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    Missing in the organizational learning literature is an integrative framework that reflects the emotional as well as the cognitive dynamics involved. Here, we take a step in this direction by focusing in depth over time (five years) on a selected organization which manufactures electronic equipment for the office industry. Drawing on personal construct theory, we define organizational learning as the collective re-construal of meaning in the direction of strategically significant themes. We suggest that emotions arise as members reflect on progress or lack of progress in achieving organizational learning. Our evidence suggests that invalidation – where organizational learning fails to correspond with expectations – gives rise to anxiety and frustration, while validation – where organizational learning is aligned with or exceeds expectations – evokes comfort or excitement. Our work aims to capture the key emotions involved as organizational learning proceeds

    Perspectives for the Delivery of Early Intervention Services via Telemedicine in Rural States: Outcomes from the COVID-19 Pandemic

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    The current study describes outcomes for seven families who participated in telehealth services from an early intervention clinic in a rural state during the COVID-19 pandemic. Families received different levels of care from a Board-Certified Behavior Analyst (BCBA®) over three months, ranging from one hour to 20 hours per week. The telemedicine sessions primarily focused on teaching caregivers to implement protocols that focused on rapport-building (i.e., Time-In [TI]), increasing child compliance with instructions (i.e., Effective Instruction Delivery [EID]), and language acquisition programs selected from the Promoting Emergence of Advanced Knowledge (PEAK) Comprehensive Assessment and Curriculum. At the conclusion of the telemedicine sessions, parents implemented the protocols with high degrees of treatment integrity, and improvements in skill acquisition on a standardized language assessment were observed for children with autism spectrum disorder (ASD). Implications for providing telemedicine services to rural and underserved communities without access to early intervention services and future directions for research are discussed

    Embedded Stellar Populations towards Young Massive Star Formation Regions I. G305.2+0.2

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    We present deep, wide-field J, H and Ks images taken with IRIS2 on the Anglo Australian Telescope, towards the massive star formation region G305.2+0.2. Combined with 3.6, 4.5, 5.8 and 8.0 micron data from the GLIMPSE survey on the Spitzer Space Telescope, we investigate the properties of the embedded stellar populations. After removing contamination from foreground stars we separate the sources based on their IR colour. Strong extended emission in the GLIMPSE images hampers investigation of the most embedded sources towards the known sites of massive star formation. However, we find a sizeable population of IR excess sources in the surrounding region free from these completeness effects. Investigation reveals the recent star formation activity in the region is more widespread than previously known. Stellar density plots show the embedded cluster in the region, G305.24+0.204, is offset from the dust emission. We discuss the effect of this cluster on the surrounding area and argue it may have played a role in triggering sites of star formation within the region. Finally, we investigate the distribution of IR excess sources towards the cluster, in particular their apparent lack towards the centre compared with its immediate environs.Comment: 16 pages, 16 figures (significantly size reduced), 2 tables, accepted MNRA

    PEG Branched Polymer for Functionalization of Nanomaterials with Ultralong Blood Circulation

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    Nanomaterials have been actively pursued for biological and medical applications in recent years. Here, we report the synthesis of several new poly(ethylene glycol) grafted branched-polymers for functionalization of various nanomaterials including carbon nanotubes, gold nanoparticles (NP) and gold nanorods (NRs), affording high aqueous solubility and stability for these materials. We synthesize different surfactant polymers based upon poly-(g-glutamic acid) (gPGA) and poly(maleic anhydride-alt-1-octadecene) (PMHC18). We use the abundant free carboxylic acid groups of gPGA for attaching lipophilic species such as pyrene or phospholipid, which bind to nanomaterials via robust physisorption. Additionally, the remaining carboxylic acids on gPGA or the amine-reactive anhydrides of PMHC18 are then PEGylated, providing extended hydrophilic groups, affording polymeric amphiphiles. We show that single-walled carbon nanotubes (SWNTs), Au NPs and NRs functionalized by the polymers exhibit high stability in aqueous solutions at different pHs, at elevated temperatures and in serum. Morever, the polymer-coated SWNTs exhibit remarkably long blood circulation (t1/2 22.1 h) upon intravenous injection into mice, far exceeding the previous record of 5.4 h. The ultra-long blood circulation time suggests greatly delayed clearance of nanomaterials by the reticuloendothelial system (RES) of mice, a highly desired property for in vivo applications of nanomaterials, including imaging and drug delivery

    Electron Self Energy for the K and L Shell at Low Nuclear Charge

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    A nonperturbative numerical evaluation of the one-photon electron self energy for the K- and L-shell states of hydrogenlike ions with nuclear charge numbers Z=1 to 5 is described. Our calculation for the 1S state has a numerical uncertainty of 0.8 Hz in atomic hydrogen, and for the L-shell states (2S and 2P) the numerical uncertainty is 1.0 Hz. The method of evaluation for the ground state and for the excited states is described in detail. The numerical results are compared to results based on known terms in the expansion of the self energy in powers of (Z alpha).Comment: 21 pages, RevTeX, 5 Tables, 6 figure

    The geography of recent genetic ancestry across Europe

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    The recent genealogical history of human populations is a complex mosaic formed by individual migration, large-scale population movements, and other demographic events. Population genomics datasets can provide a window into this recent history, as rare traces of recent shared genetic ancestry are detectable due to long segments of shared genomic material. We make use of genomic data for 2,257 Europeans (the POPRES dataset) to conduct one of the first surveys of recent genealogical ancestry over the past three thousand years at a continental scale. We detected 1.9 million shared genomic segments, and used the lengths of these to infer the distribution of shared ancestors across time and geography. We find that a pair of modern Europeans living in neighboring populations share around 10-50 genetic common ancestors from the last 1500 years, and upwards of 500 genetic ancestors from the previous 1000 years. These numbers drop off exponentially with geographic distance, but since genetic ancestry is rare, individuals from opposite ends of Europe are still expected to share millions of common genealogical ancestors over the last 1000 years. There is substantial regional variation in the number of shared genetic ancestors: especially high numbers of common ancestors between many eastern populations likely date to the Slavic and/or Hunnic expansions, while much lower levels of common ancestry in the Italian and Iberian peninsulas may indicate weaker demographic effects of Germanic expansions into these areas and/or more stably structured populations. Recent shared ancestry in modern Europeans is ubiquitous, and clearly shows the impact of both small-scale migration and large historical events. Population genomic datasets have considerable power to uncover recent demographic history, and will allow a much fuller picture of the close genealogical kinship of individuals across the world.Comment: Full size figures available from http://www.eve.ucdavis.edu/~plralph/research.html; or html version at http://ralphlab.usc.edu/ibd/ibd-paper/ibd-writeup.xhtm
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