329 research outputs found

    Stratigraphic Chart of the Waubansee Group in Nebraska

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    Centennial Guidebook to the Geology of Southeastern Nebraska

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    A Deep Search For Faint Galaxies Associated With Very Low-redshift C IV Absorbers: III. The Mass- and Environment-dependent Circumgalactic Medium

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    Using Hubble Space Telescope Cosmic Origins Spectrograph observations of 89 QSO sightlines through the Sloan Digital Sky Survey footprint, we study the relationships between C IV absorption systems and the properties of nearby galaxies as well as large-scale environment. To maintain sensitivity to very faint galaxies, we restrict our sample to 0.0015 < z < 0.015, which defines a complete galaxy survey to L > 0.01 L* or stellar mass log M_* > 8 Msun. We report two principal findings. First, for galaxies with impact parameter rho < 1 rvir, C IV detection strongly depends on the luminosity/stellar mass of the nearby galaxy. C IV is preferentially associated with galaxies with log M_* > 9.5 Msun; lower mass galaxies rarely exhibit significant C IV absorption (covering fraction f = 9 +12-6% for 11 galaxies with log M_* < 9.5 Msun). Second, C IV detection within the log M_* > 9.5 Msun population depends on environment. Using a fixed-aperture environmental density metric for galaxies with rho < 160 kpc at z < 0.055, we find that 57+/-12% (8/14) of galaxies in low-density regions (regions with fewer than seven L > 0.15 L* galaxies within 1.5 Mpc) have affiliated C IV absorption; however, none (0/7) of the galaxies in denser regions show C IV. Similarly, the C IV detection rate is lower for galaxies residing in groups with dark-matter halo masses of log Mhalo > 12.5 Msun. In contrast to C IV, H I is pervasive in the CGM without regard to mass or environment. These results indicate that C IV absorbers with log N(C IV) > 13.5 cm^-2 trace the halos of log M_* > 9.5 Msun galaxies but also reflect larger scale environmental conditions.Comment: 26 pages, 13 figures. ApJ, in pres

    Nonparametric Inference for Multivariate Data: The R Package npmv

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    We introduce the R package npmv that performs nonparametric inference for the comparison of multivariate data samples and provides the results in easy-to-understand, but statistically correct, language. Unlike in classical multivariate analysis of variance, multivariate normality is not required for the data. In fact, the different response variables may even be measured on different scales (binary, ordinal, quantitative). p values are calculated for overall tests (permutation tests and F approximations), and, using multiple testing algorithms which control the familywise error rate, significant subsets of response variables and factor levels are identified. The package may be used for low- or highdimensional data with small or with large sample sizes and many or few factor levels

    Pavement Management in Kentucky

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    The principal objective of this paper is to summarize current pavement management activities in Kentucky. Early pavement management activities generally were decentralized (involving a number of transportation functions such as planning, design, construction, maintenance, and research) and involved long-term monitoring for skid resistance and ride quality (roughness). Current pavement management activities may be categorized by evaluation, project selection, and development of recommendations for pavement rehabilitation strategies. Pavement evaluation activities at the statewide system level typically involve assessments of ride quality (ridesbility index) and estimated pavement serviceability, skid resistance, visual condition ratings, and the accumulation of traffic volumes and pavement fatigue. Funding allocations to highway districts involves the application of limiting criteria to system level data obtained during the evaluation phase. Factors considered include rideability index (estimated from roughness measurements), skid resistance, visual condition ratings, accumulation of traffic volumes and fatigue, and engineering judgment. Recommendations for rehabilitation strategies also may be based on structural evaluations using deflection measurements. Typical rehabilitation strategies are discussed. Procedures and criteria for the allocation and distribution of funding to the highway districts are presented

    Sexual health promotion and contraceptive services in local authorities: a systematic review of economic evaluations 2010-2015

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    Background Since 2013, health commissioners in England’s local authorities have been responsible for sexual health services, including contraception, HIV testing, STI testing and treatment, health education and specialist sexual health services. Effective commissioning requires information to indicate which interventions may, or may not, be cost-effective. However, current UK guidance and recent research on the cost-effectiveness of sexual health services provides patchy and fragmented evidence. This study aims systematically to review the evidence available on the cost-effectiveness of OECD-based interventions relevant to UK local authority-commissioned sexual health services. Methods Key informants, bibliographic database searches and reference lists of guidance documents and included studies were searched for potentially relevant research. Guided by key stakeholders, we sought economic evaluations of sexual health interventions within the responsibility of local authorities, and focused in the UK, on contraception and on health promotion, published between 2010 and 2015 in English. Eligible studies were full economic evaluations based in an OECD country. Studies were classified using a specifically developed tool and assessed for methodological risk of bias using one of three design-specific assessment tools. Descriptive frequencies of codes were analysed to provide a ‘map’ of research that informed stakeholder discussions to focus the subsequent synthesis. The characteristics of studies, quality ratings and cost outcomes from each included study were extracted into tables and findings summarised narratively. Studies were assessed for their relative cost-saving or cost-effectiveness according to NICE guidance. Results In total, 17,705 references were screened; of these, 29 met our inclusion criteria and were included in the synthesis. Nine studies were undertaken in the UK; the remainder were US based. Fifteen studies examined the economics of contraception and 14 evaluated health promotion. Overall, studies were of medium methodological quality. In general, economic evaluations of contraception reported cost-effectiveness or cost savings for ulipristal acetate (UPA) as emergency contraception, long-acting reversible contraceptives (LARCs) for regular, post-natal and post-abortion contraception, and targeting to high risk groups; none, however, reported costs per quality-adjusted life year (QALY) within NICE thresholds. Economic evaluations of sexual health promotion interventions indicated more mixed results. Only three interventions were found to be cost-effective according to the NICE thresholds for HIV or sexually transmitted infection (STI) outcomes: nurse-led rapid testing and tailored counselling; condom negotiations skills training for female sex workers; and a teacher-led STI prevention and skills training intervention. UK studies focused on health promotion and contraception, and supported the above findings. In general, there has been a reasonable amount of economic research into sexual health interventions since 2010, and these support current NICE sexual health guidance. Abstract Sexual health promotion and contraceptive services in local authorities: a systematic review of economic evaluations 2010-2015 vi Conclusions The broad nature of the research question posed in this systematic review resulted in the inclusion of a dataset very diverse in terms of populations, interventions, outcomes and types of economic evaluation designs. In considering the cost-effectiveness of these strategies in relation to their own commissioning climate, policy and decision makers should consider carefully the fit between their context and that of individual studies. Use of longer-term outcomes in trials used in economic evaluations would strengthen estimates of effects such as QALYs, as would the routine use of longitudinal cohort data

    How Cosmic Web Environment Affects Galaxy Quenching Across Cosmic Time

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    We investigate how cosmic web structures affect galaxy quenching in the IllustrisTNG (TNG-100) cosmological simulations by reconstructing the cosmic web in each snapshot using the DisPerSE framework. We measure the distance from each galaxy with stellar mass log(M*/Msun)>=8 to the nearest node (dnode) and the nearest filament spine (dfil) and study the dependence of both median specific star formation rate () and median gas fraction () on these distances. We find that of galaxies is only dependent on cosmic web environment at z<2, with the dependence increasing with time. At z<=0.5, 8<=log(M*/Msun)<9 galaxies are quenched at dnode<1 Mpc, and significantly star formation-suppressed at dfil<1 Mpc, trends which are driven mostly by satellite galaxies. At z of log(M*/Msun)=10 galaxies actually experience an upturn in at dnode<0.2 Mpc (this is caused by both satellites and centrals). Much of this cosmic web-dependence of star formation activity can be explained by the evolution in . Our results suggest that in the past ~10 Gyr, low-mass satellites are quenched by rapid gas stripping in dense environments near nodes and gradual gas starvation in intermediate-density environments near filaments, while at earlier times cosmic web structures efficiently channeled cold gas into most galaxies. State-of-the-art ongoing spectroscopic surveys such as SDSS and DESI, as well as those planned with JWST and Roman are required to test our predictions against observations.Comment: 5 Figures, 15 pages, submitted to ApJ Letter

    Filaments of The Slime Mold Cosmic Web And How They Affect Galaxy Evolution

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    We present a novel method for identifying cosmic web filaments using the IllustrisTNG (TNG100) cosmological simulations and investigate the impact of filaments on galaxies. We compare the use of cosmic density field estimates from the Delaunay Tessellation Field Estimator (DTFE) and the Monte Carlo Physarum Machine (MCPM), which is inspired by the slime mold organism, in the DisPerSE structure identification framework. The MCPM-based reconstruction identifies filaments with higher fidelity, finding more low-prominence/diffuse filaments and better tracing the true underlying matter distribution than the DTFE-based reconstruction. Using our new filament catalogs, we find that most galaxies are located within 1.5-2.5 Mpc of a filamentary spine, with little change in the median specific star formation rate and the median galactic gas fraction with distance to the nearest filament. Instead, we introduce the filament line density, {\Sigma}fil(MCPM), as the total MCPM overdensity per unit length of a local filament segment, and find that this parameter is a superior predictor of galactic gas supply and quenching. Our results indicate that most galaxies are quenched and gas-poor near high-line density filaments at z10.5 galaxies is mainly driven by mass, while lower-mass galaxies are significantly affected by the filament line density. In high-line density filaments, satellites are strongly quenched, whereas centrals have reduced star formation, but not gas fraction, at z<=0.5. We discuss the prospect of applying our new filament identification method to galaxy surveys with SDSS, DESI, Subaru PFS, etc. to elucidate the effect of large-scale structure on galaxy formation.Comment: Submitted to ApJ, comments welcome. Data available at https://github.com/farhantasy/CosmicWeb-Galaxies
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