1,105 research outputs found

    Public Procurement Systems: Unpacking Stakeholder Aspirations and Expectations

    Get PDF
    Around the world, governments are increasingly becoming focused on improving their public procurement regimes. Significant developments include the establishment of internationally shared norms for public procurement systems, while, at the national level, a number of countries have adopted dramatically new public procurement regimes, and others are experimenting with new procurement vehicles, such as framework agreements and electronic reverse auctions, and new procurement schemes, including public-private partnerships. As each of these changes is contemplated, planned, implemented, and then assessed, government leaders and policy makers need a framework of analysis for decision making - a framework based on public procurement goals and understanding stakeholder interests.In this condensed working paper (being delivered at the Naval Postgraduate School Acquisition Symposium), we offer such a framework, building on the ideas in Steve Schooner\u27s 2002 article, \u27Desiderata: Objectives for a System of Government Contract Law.\u27 In that article, Schooner outlined nine objectives, or desiderata, of public procurement systems: competition, integrity, transparency, efficiency, customer satisfaction, best value, wealth distribution, risk avoidance, and uniformity. From that starting point, we use stakeholder analysis to further develop the desiderata into a two-part framework to give policy makers and government leaders a tool for public procurement decision making. Just as \u27Desiderata\u27 has contributed to public procurement decision making, this analytical framework can help clarify, and perhaps inform, many of the debates raging around procurement reform

    Impacts of Remotely Sensed Land Use Data on Watershed Hydrologic Change Assessment

    Get PDF
    Urbanization affects the stream system of a watershed. Increased urbanization alters the land cover and surface characteristics, the stream channel characteristics, and pollutant load of a stream system by increasing the amount of impervious surface. Once rural, forest, or wetland areas are changed to streets, highways, parking lots, sidewalks, and building rooftops. This results in large volumes of runoff being generated for an intense storm over a relatively short time period. As a result, sensitive ecosystems are likely to be damaged by increased urbanization. Projecting the impact of land use changes on a watershed scale often requires the use of remote sensing data to derive the required inputs on land cover and the related amount of impervious surface. Such forecasts are then used to devise alternative land use and stormwater control policies. One critical question that arises then is the impact of land use/land cover (LULC) mapping error on the resulting hydrologic model projections. In this research, we developed a methodology to assess those impacts. The Hydrologic Engineering Center-Hydrologic Modeling System (HEC-HMS) model was used to estimate the peak hydrograph for a baseline land use condition and then used to estimate the impact of LULC mapping accuracy levels on those forecasts. The Big Darby Creek Watershed located near Columbus, Ohio, which is experiencing increased urbanization, was selected to map LULC, calibrate a hydrologic model, and assess the hydrologic change due to LULC mapping error. The resulting analysis showed that modest changes in land cover classification did not produce significant impacts on the hydrologic modeling results in rural basins. However, the hydrologic changes are noticeable in urbanizing watersheds. The framework developed in this paper can be used for future modeling efforts to understand the hydrological impact of LULC change in a watershed at a large scale

    Nonlinear Response of Tropical Lower Stratospheric Temperature and Water Vapor to ENSO

    Get PDF
    A series of simulations using the NASA Goddard Earth Observing System Chemistry-Climate Model are analyzed in order to aid in the interpretation of observed interannual and sub-decadal variability in the tropical lower stratosphere over the past 35 years. The impact of El Nino-Southern Oscillation on temperature and water vapor in this region is nonlinear in boreal spring. While moderate El Nino events lead to cooling in this region, strong El Nino events lead to warming, even as the response of the large-scale Brewer Dobson circulation appears to scale nearly linearly with El Nino. This nonlinearity is shown to arise from the response in the Indo-West Pacific to El Nino: strong El Nino events lead to tropospheric warming extending into the tropical tropopause layer and up to the cold point in this region, where it allows for more water vapor to enter the stratosphere. The net effect is that both strong La Nina and strong El Nino events lead to enhanced entry water vapor and stratospheric moistening in boreal spring and early summer. These results lead to the following interpretation of the contribution of sea surface temperatures to the decline in water vapor in the early 2000s: the very strong El Nino event in 1997/1998, followed by more than 2 consecutive years of La Nina, led to enhanced lower-stratospheric water vapor. As this period ended in early 2001, entry water vapor concentrations declined. This effect accounts for approximately one-quarter of the observed drop

    Developing an advanced module for back-contact solar cells

    Get PDF
    This paper proposes a novel concept for integrating ultrathin solar cells into modules. It is conceived as a method for fabricating solar panels starting from back-contact crystalline silicon solar cells. However, compared to the current state of the art in module manufacturing for back-contact solar cells, this novel concept aims at improvements in performance, reliability, and cost through the use of an alternative encapsulant, namely silicones as opposed to ethylene vinyl acetate, an alternative deposition technology, being wet coating as opposed to dry lamination; and alternative module-level metallization techniques, as opposed to cell-level tabbing-stringing or conductive foil interconnects. The process flow is proposed, and the materials and fabrication technologies are discussed. As the durability of the module, translated into the module's lifetime, is very important in the targeted application, namely solar cell modules, modeling and reliability testing results and considerations are presented to illustrate how the experimental development process may be guided by experience and theoretical derivations. Finally, feasibility is demonstrated in some first proofs of the concept, and an outlook is given pointing out the direction for further research

    Escherichia coli from urine of female patients with urinary tract infections is competent for intracellular bacterial community formation

    Get PDF
    Nearly 50% of women experience at least one urinary tract infection (UTI) in their lifetime. Studies with mice have revealed that uropathogenic Escherichia coli (UPEC) isolates invade superficial umbrella cells that line the bladder, allowing them to find a safe haven and subvert clearance by innate host responses. Rapid intracellular replication results in the formation of distinctive intracellular bacterial communities (IBCs). In this study, we evaluated whether UPEC strains cultured from the urine of women and classified as causing acute cystitis, recurrent cystitis, asymptomatic bacteriuria, or pyelonephritis could progress through the IBC cascade in a well-characterized mouse model of cystitis. Of 18 UPEC isolates collected from women, 15 formed IBCs. Variations in the size, number, and kinetics of IBC formation were observed with strains isolated from women with different clinical syndromes. Two of the three isolates that did not form IBCs when inoculated alone were able to do so when coinoculated with an isolate that was capable of generating IBCs. The mixed infections dramatically altered the behavior of the coinfecting bacteria relative to their behavior in a single infection. The study also showed that mice with five different genetic backgrounds can support IBC formation. Although UPEC isolates differ genetically in their virulence factors, the majority of UPEC isolates from different types of UTI proceed through the IBC pathway, confirming the generality of IBCs in UTI pathogenesis in mice

    Glecaprevir and pibrentasvir for 12 weeks for hepatitis C virus genotype 1 infection and prior direct-acting antiviral treatment: Poordad et al.

    Get PDF
    Although direct‐acting antiviral (DAA) therapies for chronic hepatitis C virus (HCV) infection have demonstrated high rates of sustained virologic response, virologic failure may still occur, potentially leading to the emergence of viral resistance, which can decrease the effectiveness of subsequent treatment. Treatment options for patients who failed previous DAA‐containing regimens, particularly those with nonstructural protein 5A inhibitors, are limited and remain an area of unmet medical need. This phase 2, open‐label study (MAGELLAN‐1) evaluated the efficacy and safety of glecaprevir (GLE) + pibrentasvir (PIB) ± ribavirin (RBV) in HCV genotype 1–infected patients with prior virologic failure to HCV DAA‐containing therapy. A total of 50 patients without cirrhosis were randomized to three arms: 200 mg GLE + 80 mg PIB (arm A), 300 mg GLE + 120 mg PIB with 800 mg once‐daily RBV (arm B), or 300 mg GLE + 120 mg PIB without RBV (arm C). By intent‐to‐treat analysis, sustained virologic response at posttreatment week 12 was achieved in 100% (6/6, 95% confidence interval 61‐100), 95% (21/22, 95% confidence interval 78‐99), and 86% (19/22, 95% confidence interval 67‐95) of patients in arms A, B, and C, respectively. Virologic failure occurred in no patients in arm A and in 1 patient each in arms B and C (two patients were lost to follow‐up in arm C). The majority of adverse events were mild in severity; no serious adverse events related to study drug and no relevant laboratory abnormalities in alanine aminotransferase, total bilirubin, or hemoglobin were observed. Conclusion: The combination of GLE and PIB was highly efficacious and well tolerated in patients with HCV genotype 1 infection and prior failure of DAA‐containing therapy; RBV coadministration did not improve efficacy. (Hepatology 2017;66:389–397)

    Apolipoprotein E is a pancreatic extracellular factor that maintains mature β-cell gene expression.

    Get PDF
    The in vivo microenvironment of tissues provides myriad unique signals to cells. Thus, following isolation, many cell types change in culture, often preserving some but not all of their in vivo characteristics in culture. At least some of the in vivo microenvironment may be mimicked by providing specific cues to cultured cells. Here, we show that after isolation and during maintenance in culture, adherent rat islets reduce expression of key β-cell transcription factors necessary for β-cell function and that soluble pancreatic decellularized matrix (DCM) can enhance β-cell gene expression. Following chromatographic fractionation of pancreatic DCM, we performed proteomics to identify soluble factors that can maintain β-cell stability and function. We identified Apolipoprotein E (ApoE) as an extracellular protein that significantly increased the expression of key β-cell genes. The ApoE effect on beta cells was mediated at least in part through the JAK/STAT signaling pathway. Together, these results reveal a role for ApoE as an extracellular factor that can maintain the mature β-cell gene expression profile
    • …
    corecore