7,157 research outputs found

    A study of HII regions in spiral galaxies using multiobject spectroscopy

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    Multiobject spectroscopy results of HII regions in nearby late-type spiral galaxies are given. Results include excitation measurements, log ((O III)/H beta), for 81 regions in M 101, 30 regions in NGC 2403, and 13 regions in M 51. Researchers conclude that late-type spirals can be classified into two distinct populations, examine possible causes of this division, and derive metallicity gradients for these galaxies. M 51 appears to have an anomalously shallow abundance gradient

    New Distributional Record for \u3ci\u3eBalcha Indica\u3c/i\u3e (Hymenoptera: Eupelmidae) in Eastern West Virginia Discovered During Emerald Ash Borer Parasitoid Recovery Surveys

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    Between 2010 and 2012, approximately 6,300 Spathius agrili Yang (Hymenoptera: Braconidae) and 9,500 Tetrastichus planipennisi Yang (Hymenoptera: Eulophidae) parasitoids were released for biological control of the invasive emerald ash borer, Agrilus planipennis Fairmaire, at Cacapon State Park and the Cool Front Development in Morgan County, West Virginia. The invasive beetle was first detected there in 2009, and extensive ash mortality is currently occurring. We conducted parasitoid recovery surveys in 2013 but did not recover either of the released parasitoid species. However, we did rear Balcha indica Mani and Kaul (Hymenoptera: Eupelmidae), which is native to Asia and is a documented parasitoid of A. planipennis, from bolts infested with A. planipennis. This is the first documented record of B. indica for West Virginia

    Residual finiteness of extensions of arithmetic subgroups of SU(d,1){{\,\mathrm{SU}\,}}(d,1) with cusps

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    Let Γ be an arithmetic subgroup of SU(d,1) with cusps, and let XΓ be the associated locally symmetric space. In this paper we investigate the pre-image of Γ in the covering groups of SU(d,1). Let H∙!(XΓ,C) be the inner cohomology, i.e. the image in H∙(XΓ,C) of the compactly supported cohomology. We prove that if the first inner cohomology group H1!(XΓ,C) is non-zero then the pre-image of Γ in each connected cover of SU(d,1) is residually finite. At the end of the paper we give an example of an arithmetic subgroup Γ satisfying the criterion H1!(XΓ,C)≠0

    Power Corrections to the Universal Heavy WIMP-Nucleon Cross Section

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    WIMP-nucleon scattering is analyzed at order 1/M1/M in Heavy WIMP Effective Theory. The 1/M1/M power corrections, where MmWM\gg m_W is the WIMP mass, distinguish between different underlying UV models with the same universal limit and their impact on direct detection rates can be enhanced relative to naive expectations due to generic amplitude-level cancellations at leading order. The necessary one- and two-loop matching calculations onto the low-energy effective theory for WIMP interactions with Standard Model quarks and gluons are performed for the case of an electroweak SU(2) triplet WIMP, considering both the cases of elementary fermions and composite scalars. The low-velocity WIMP-nucleon scattering cross section is evaluated and compared with current experimental limits and projected future sensitivities. Our results provide the most robust prediction for electroweak triplet Majorana fermion dark matter direct detection rates; for this case, a cancellation between two sources of power corrections yields a small total 1/M1/M correction, and a total cross section close to the universal limit for Mfew×100GeVM \gtrsim {\rm few} \times 100\,{\rm GeV}. For the SU(2) composite scalar, the 1/M1/M corrections introduce dependence on underlying strong dynamics. Using a leading chiral logarithm evaluation, the total 1/M1/M correction has a larger magnitude and uncertainty than in the fermionic case, with a sign that further suppresses the total cross section. These examples provide definite targets for future direct detection experiments and motivate large scale detectors capable of probing to the neutrino floor in the TeV mass regime.Comment: 12 pages, 4 figures; references added, XENONnT projection included, version to appear in Physics Letters

    Water Quality, Stormwater Management, and Development Planning on the Urban Fringe

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    This Article reports on a study to formulate an environmental plan for a large development project in Austin, Texas. The issue was stormwater quality, and the principal concern was the meaningfulness of Austin\u27s environmental ordinance, which is based on environmental indicators. We present an alternative approach to planning for stormwater management: one based on the form and function of the runoff system. The development project, called Steiner Ranch, is a 4600-acre parcel in the Hill Country, fifteen miles west of Austin

    Do Agency Administrative Changes Affect the Effectiveness and Efficiency of DHR Employees?

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    This study examined the perceived effectiveness and efficiency of DHR employees before and after agency administrative changes. Results indicated that the employees\u27 perceptions of effectiveness and efficiency after agency administrative changes were not significantly affected. The employees also felt that communication was the major factor hindering them in becoming more effective and efficient

    Data Acquisition System Architecture and Capabilities at NASA GRC Plum Brook Station's Space Environment Test Facilities

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    Very large space environment test facilities present unique engineering challenges in the design of facility data systems. Data systems of this scale must be versatile enough to meet the wide range of data acquisition and measurement requirements from a diverse set of customers and test programs, but also must minimize design changes to maintain reliability and serviceability. This paper presents an overview of the common architecture and capabilities of the facility data acquisition systems available at two of the world's largest space environment test facilities located at the NASA Glenn Research Center's Plum Brook Station in Sandusky, Ohio; namely, the Space Propulsion Research Facility (commonly known as the B-2 facility) and the Space Power Facility (SPF). The common architecture of the data systems is presented along with details on system scalability and efficient measurement systems analysis and verification. The architecture highlights a modular design, which utilizes fully-remotely managed components, enabling the data systems to be highly configurable and support multiple test locations with a wide-range of measurement types and very large system channel counts

    Integrating biological knowledge into variable selection : an empirical Bayes approach with an application in cancer biology

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    Background: An important question in the analysis of biochemical data is that of identifying subsets of molecular variables that may jointly influence a biological response. Statistical variable selection methods have been widely used for this purpose. In many settings, it may be important to incorporate ancillary biological information concerning the variables of interest. Pathway and network maps are one example of a source of such information. However, although ancillary information is increasingly available, it is not always clear how it should be used nor how it should be weighted in relation to primary data. Results: We put forward an approach in which biological knowledge is incorporated using informative prior distributions over variable subsets, with prior information selected and weighted in an automated, objective manner using an empirical Bayes formulation. We employ continuous, linear models with interaction terms and exploit biochemically-motivated sparsity constraints to permit exact inference. We show an example of priors for pathway- and network-based information and illustrate our proposed method on both synthetic response data and by an application to cancer drug response data. Comparisons are also made to alternative Bayesian and frequentist penalised-likelihood methods for incorporating network-based information. Conclusions: The empirical Bayes method proposed here can aid prior elicitation for Bayesian variable selection studies and help to guard against mis-specification of priors. Empirical Bayes, together with the proposed pathway-based priors, results in an approach with a competitive variable selection performance. In addition, the overall procedure is fast, deterministic, and has very few user-set parameters, yet is capable of capturing interplay between molecular players. The approach presented is general and readily applicable in any setting with multiple sources of biological prior knowledge
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