1,192 research outputs found

    Higher Education Scorecards, Performance Based Metrics, and Faculty Compensation

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    U ovom radu rješavao se problem projektiranja jednokanalnog EKG pojačala. Projektirao se prema ulaznim zahtjevima prema kojima je predviđeno napajanje pojačala baterijom nominalnog napona 3,7 V, mora imati 2 načina rada: dijagnostički (0,05 – 120 Hz) i monitoriranje (1 – 45 Hz), a ulazni filtar mora biti niskopropusni. Kao ulazni filtar odabran je niskopropusni RC filtar. Nakon pojačanja u instrumentacijskom pojačalu, guše se niske frekvencije u Besselovom visokopropusnom filtru. Na kraju se signal dodatno pojačava u neinvertirajućem pojačalu. Dobiveno je pojačalo karakteristika bliskih zahtijevanim. Izmjeren je EKG na ispitaniku pri čemu je dobiven očekivani signal na izlazu.This thesis is based on a problem of designing a single – channel electrocardiogram. Its design is based on given specifications which include 3,7 V single power supply, low – pass filter in its input stage and ability to work in two different modes chosen by the user: diagnosting mode (0,05 – 120 Hz) and monitoring mode (1 – 45 Hz). The chosen input stage filter is low – pass RC filter. After amplifying the signal in an instrumentation amplifier, low frequencies are attenuated in a high – pass Bessel filter. Finally, the signal is amplified in a non – inverting amplifier. As a result, the designed ECG amplifier was confirmed to have very close specifications to the ones requested. Finally, ECG was measured on a test subject which resulted in expected output signals

    Shiga toxin production and translocation during microaerobic human colonic infection with Shiga toxin-producing E. coli O157:H7 and O104:H4

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    Haemolytic uraemic syndrome caused by Shiga toxin-producing E. coli (STEC) is dependent on release of Shiga toxins (Stxs) during intestinal infection and subsequent absorption into the bloodstream. An understanding of Stx-related events in the human gut is limited due to lack of suitable experimental models. In this study, we have used a vertical diffusion chamber system with polarized human colon carcinoma cells to simulate the microaerobic (MA) environment in the human intestine and investigate its influence on Stx release and translocation during STEC O157:H7 and O104:H4 infection. Stx2 was the major toxin type released during infection. Whereas microaerobiosis significantly reduced bacterial growth as well as Stx production and release into the medium, Stx translocation across the epithelial monolayer was enhanced under MA versus aerobic conditions. Increased Stx transport was dependent on STEC infection and occurred via a transcellular pathway other than macropinocytosis. While MA conditions had a similar general effect on Stx release and absorption during infection with STEC O157:H7 and O104:H4, both serotypes showed considerable differences in colonization, Stx production, and Stx translocation which suggest alternative virulence strategies. Taken together, our study suggests that the MA environment in the human colon may modulate Stx-related events and enhance Stx absorption during STEC infection

    Bacterial-epithelial contact is a key determinant of host innate immune responses to enteropathogenic and enteroaggregative escherichia coli

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    Background: Enteropathogenic (EPEC) and Enteroaggregative (EAEC) E. coli have similar, but distinct clinical symptoms and modes of pathogenesis. Nevertheless when they infect the gastrointestinal tract, it is thought that their flagellin causes IL-8 release leading to neutrophil recruitment and gastroenteritis. However, this may not be the whole story as the effect of bacterial adherence to IEC innate response(s) remains unclear. Therefore, we have characterized which bacterial motifs contribute to the innate epithelial response to EPEC and EAEC, using a range of EPEC and EAEC isogenic mutant strains. Methodology: Caco-2 and HEp-2 cell lines were exposed to prototypical EPEC strain E2348/69 or EAEC strain O42, in addition to a range of isogenic mutant strains. E69 [LPS, non-motile, non-adherent, type three secretion system (TTSS) negative, signalling negative] or O42 [non-motile, non-adherent]. IL-8 and CCL20 protein secretion was measured. Bacterial surface structures were assessed by negative staining Transmission Electron Microscopy. The Fluorescent-actin staining test was carried out to determine bacterial adherence. Results: Previous studies have reported a balance between the host pro-inflammatory response and microbial suppression of this response. In our system an overall balance towards the host pro-inflammatory response is seen with the E69 WT and to a greater extent O42 WT, which is in fit with clinical symptoms. On removal of the external EPEC structures flagella, LPS, BFP, EspA and EspC; and EAEC flagella and AAF, the host inflammatory response is reduced. However, removal of E69 lymphostatin increases the host inflammatory response suggesting involvement in the bacterial mediated anti-inflammatory response. Conclusion: Epithelial responses were due to combinations of bacterial agonists, with host-bacterial contact a key determinant of these innate responses. Host epithelial recognition was offset by the microbe's ability to down-regulate the inflammatory response. Understanding the complexity of this host-microbial balance will contribute to improved vaccine design for infectious gastroenteritis

    NASA Advanced Concepts Office, Earth-To-Orbit Team Design Process and Tools

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    The Earth-to-Orbit Team (ETO) of the Advanced Concepts Office (ACO) at NASA Marshall Space Flight Center (MSFC) is considered the pre-eminent "go-to" group for pre-phase A and phase A concept definition. Over the past several years the ETO team has evaluated thousands of launch vehicle concept variations for a significant number of studies including agency-wide efforts such as the Exploration Systems Architecture Study (ESAS), Constellation, Heavy Lift Launch Vehicle (HLLV), Augustine Report, Heavy Lift Propulsion Technology (HLPT), Human Exploration Framework Team (HEFT), and Space Launch System (SLS). The ACO ETO Team is called upon to address many needs in NASA's design community; some of these are defining extremely large trade-spaces, evaluating advanced technology concepts which have not been addressed by a large majority of the aerospace community, and the rapid turn-around of highly time critical actions. It is the time critical actions, those often limited by schedule or little advanced warning, that have forced the five member ETO team to develop a design process robust enough to handle their current output level in order to meet their customer's needs. Based on the number of vehicle concepts evaluated over the past year this output level averages to four completed vehicle concepts per day. Each of these completed vehicle concepts includes a full mass breakdown of the vehicle to a tertiary level of subsystem components and a vehicle trajectory analysis to determine optimized payload delivery to specified orbital parameters, flight environments, and delta v capability. A structural analysis of the vehicle to determine flight loads based on the trajectory output, material properties, and geometry of the concept is also performed. Due to working in this fast-paced and sometimes rapidly changing environment, the ETO Team has developed a finely tuned process to maximize their delivery capabilities. The objective of this paper is to describe the interfaces between the three disciplines used in the design process: weights and sizing, trajectory, and structural analysis. The tools used to perform such analysis are INtegrated Rocket Sizing (INTROS), Program to Optimize Simulated Trajectories (POST), and Launch Vehicle Analysis (LVA) respectively. The methods each discipline uses to streamline their particular part of the design process will also be discussed

    NASA Advanced Concepts Office, Earth-To-Orbit Team Design Process and Tools

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    The Earth-to-Orbit Team (ETO) of the Advanced Concepts Office (ACO) at NASA Marshall Space Flight Center (MSFC) is considered the pre-eminent go-to group for pre-phase A and phase A concept definition. Over the past several years the ETO team has evaluated thousands of launch vehicle concept variations for a significant number of studies including agency-wide efforts such as the Exploration Systems Architecture Study (ESAS), Constellation, Heavy Lift Launch Vehicle (HLLV), Augustine Report, Heavy Lift Propulsion Technology (HLPT), Human Exploration Framework Team (HEFT), and Space Launch System (SLS). The ACO ETO Team is called upon to address many needs in NASA s design community; some of these are defining extremely large trade-spaces, evaluating advanced technology concepts which have not been addressed by a large majority of the aerospace community, and the rapid turn-around of highly time critical actions. It is the time critical actions, those often limited by schedule or little advanced warning, that have forced the five member ETO team to develop a design process robust enough to handle their current output level in order to meet their customer s needs. Based on the number of vehicle concepts evaluated over the past year this output level averages to four completed vehicle concepts per day. Each of these completed vehicle concepts includes a full mass breakdown of the vehicle to a tertiary level of subsystem components and a vehicle trajectory analysis to determine optimized payload delivery to specified orbital parameters, flight environments, and delta v capability. A structural analysis of the vehicle to determine flight loads based on the trajectory output, material properties, and geometry of the concept is also performed. Due to working in this fast-paced and sometimes rapidly changing environment, the ETO Team has developed a finely tuned process to maximize their delivery capabilities. The objective of this paper is to describe the interfaces between the three disciplines used in the design process: weights and sizing, trajectory, and structural analysis. The tools used to perform such analysis are INtegrated Rocket Sizing (INTROS), Program to Optimize Simulated Trajectories (POST), and Launch Vehicle Analysis (LVA) respectively. The methods each discipline uses to streamline their particular part of the design process will also be discussed

    Bound on Lorentz- and CPT-Violating Boost Effects for the Neutron

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    A search for an annual variation of a daily sidereal modulation of the frequency difference between co-located 129{}^{129}Xe and 3{}^{3}He Zeeman masers sets a stringent limit on boost-dependent Lorentz and CPT violation involving the neutron, consistent with no effect at the level of 150 nHz. In the framework of the general Standard-Model Extension, the present result provides the first clean test for the fermion sector of the symmetry of spacetime under boost transformations at a level of 102710^{-27} GeV.Comment: 4 pages, 1 figur

    Totally Magic Graphs

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    A total labeling of a graph with v vertices and e edges is defined as a one-to-one map taking the vertices and edges onto the integers 1, 2, · · · , v+e. Such a labeling is vertex magic if the sum of the label on a vertex and the labels on its incident edges is a constant independent of the choice of vertex, and edge magic if the sum of an edge label and the labels of the endpoints of the edge is constant. In this paper we examine graphs possessing a labeling that is simultaneously vertex magic and edge magic. Such graphs appear to be rare

    Moderate-Intensity Exercise Improves Body Composition and Improves Physiological Markers of Stress in HIV-Infected Men

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    HIV/AIDS and its treatment often alter body composition and result in poorer physical functioning. The aim of this study was to determine the effects of a moderate-intensity exercise program on body composition and the hormones and cytokines associated with adverse health outcomes. HIV-infected males (N = 111) were randomized to an exercise group (EX) who completed 6 weeks of moderate-intensity exercise training, or to a nonintervention control group (CON). In pre- and postintervention, body composition was estimated via DXA, peak strength was assessed, and resting blood samples were obtained. There was a decrease in salivary cortisol at wake (P = 0.025) in the EX and a trend (P = 0.07) for a decrease 1 hour after waking. The EX had a significant increase in lean tissue mass (LTM) (P \u3c 0.001) following the intervention. Those in the EX below median body fat (20%) increased LTM (P = 0.014) only, while those above 20% decreased fat mass (P = 0.02), total fat (N = 0.009), and trunk fat (P = 0.001), while also increasing LTM (P = 0.027). Peak strength increased between 14% and 28% on all exercises in the EX group. These data indicate that 6 weeks of moderate-intensity exercise training can decrease salivary cortisol levels, improve physical performance, and improve body composition in HIV-infected men

    Why coordinated distributed experiments should go global

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    The performance of coordinated distributed experiments designed to compare ecosystem sensitivity to global-change drivers depends on whether they cover a significant proportion of the global range of environmental variables. In the present article, we described the global distribution of climatic and soil variables and quantified main differences among continents. Then, as a test case, we assessed the representativeness of the International Drought Experiment (IDE) in parameter space. Considering the global environmental variability at this scale, the different continents harbor unique combinations of parameters. As such, coordinated experiments set up across a single continent may fail to capture the full extent of global variation in climate and soil parameter space. IDE with representation on all continents has the potential to address global scale hypotheses about ecosystem sensitivity to environmental change. Our results provide a unique vision of climate and soil variability at the global scale and highlight the need to design globally distributed networks.Fil: Yahdjian, María Laura. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones Fisiológicas y Ecológicas Vinculadas a la Agricultura. Universidad de Buenos Aires. Facultad de Agronomía. Instituto de Investigaciones Fisiológicas y Ecológicas Vinculadas a la Agricultura; ArgentinaFil: Sala, Osvaldo Esteban. Indiana University; Estados Unidos. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Piñeiro Guerra, Juan Manuel. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones Fisiológicas y Ecológicas Vinculadas a la Agricultura. Universidad de Buenos Aires. Facultad de Agronomía. Instituto de Investigaciones Fisiológicas y Ecológicas Vinculadas a la Agricultura; ArgentinaFil: Knapp, Alan K.. State University of Colorado - Fort Collins; Estados UnidosFil: Collins, Scott L.. University of New Mexico; Estados UnidosFil: Phillips, Richard P.. State University of Colorado - Fort Collins; Estados UnidosFil: Smith, Melinda D.. State University of Colorado - Fort Collins; Estados Unido
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