2,513 research outputs found
A Transfer Report on the Development of a Framework to Evaluate Search Interfaces for their Support of Different User Types and Search Tactics
No full textAs the understanding of search systems, user needs and seeking strategies is developing, the design of search user interfaces is evolving to support more complicated and exploratory forms of search. With the design of new search features that enable these richer modes of exploration, comes the need to better understand the support they provide. In this report a new evaluation framework is presented that analyses search features for how they a) contribute to an overall interface, b) allow users to carry out different search tactics, and c) support different types of users and their needs. The novel contributions of the framework improve on some of the limitations of typical user studies, and allow search systems to be systematically analysed in much more detail and in much less time. The presented evaluation framework is then validated in three ways. First the validity of the models used as the building blocks of the framework are investigated through related work. Second the method of integrating these building-block models is validated and strengthened by consensus of expert opinion. Third, the overall approach is validated by comparing its analyses to the results of previously carried out user studies. The validation process has shown both the value of the framework and identified areas of future work that should be addressed for the framework to be completed. This report concludes with the set of contributions that the framework makes, and why the remaining work will be challenging, but critical to the final design
Combining Max-min and Max-max Approaches for Robust SoS Architecting
No full textAbstractA System of Systems (SoS) architecting problem requires creating a selection of systems in order to provide a set of capabilities. SoS architecting finds many applications in military/defense projects. In this paper, we study a multi-objective SoS architecting problem, where the cost of the architecture is minimized while its performance is maximized. The cost of the architecture is the summation of the costs of the systems to be included in the SoS. Similarly, the performance of the architecture is defined as the sum of the performance of the capabilities, where the performance of a capability is the sum of the selected systems’ contributions towards its performance. Here, nevertheless, the performance of a system in providing a capability is not known with certainty. To model this uncertainty, we assume that the performance of a system for providing a capability has lower and upper bounds and subject to complete uncertainty, i.e., no information is available about the probability distribution of the performance values. To solve the resulting multi-objective SoS architecting problem with uncertainty, we propose and compare three robust approaches: max-min, max-max, and max-mid. We apply these methods on a military example and numerically compare the results of the different approaches
Reductive debromination by sponge-associated anaerobic bacteria coupled to carbon isotope fractionation
No full textMarine sponges contain diverse brominated compounds as secondary metabolites and the sponge habitat appears to enrich for a population of anaerobic dehalogenating bacteria. Hence, there is interest in understanding how these natural and anthropogenic compounds are degraded in the marine environment. Compound specific isotope analysis (CSIA) is a useful tool to monitor and to quantify the degradation and fate of aquatic pollutants. The objective of this study was to evaluate whether reductive dehalogenation of brominated phenols by sponge-associated bacteria, including Desulfoluna spongiiphila, can be monitored by CSIA. Debromination of 2,6-dibromophenol to phenol by sponge-associated cultures resulted in measurable stable carbon isotope fractionation. All sponge-associated cultures showed similar isotopic enrichment factors (ε). The ε values for two independent sponge-derived dehalogenating cultures were -3.1 ± 1.5 ‰, and -3.0 ± 0.3 ‰, and that of sponge associated sediment cultures -2.0 ± 0.3 ‰. Thus, we demonstrate that reductive debromination of 2,6- dibromophenol resulted in measurable carbon isotope fractionation and that CSIA can be used to assess reductive debromination and to monitor and estimate in vivo dehalogenation in a sponge animal.Peer reviewe
Regulation of Business - Sherman Act - Expansion of Per Se Doctrine Over Tying Agreements
No full textThrough congressional grant defendant\u27s predecessor acquired approximately forty million acres of land, consisting of every alternate section in a twenty to forty mile wide belt on each side of its railroad track from Lake Superior to Puget Sound. Defendant sold about thirty-seven million acres of its holdings and leased the balance. Many of the sales contracts and most of the leases, together covering several million acres of land, contained preferential routing clauses which compelled the grantee or lessee to ship all commodities produced or manufactured on the land over defendant\u27s lines, unless competitors\u27 rates were lower or, in some instances, unless their services were better. In an action for injunctive relief by the government, charging that defendant\u27s preferential routing, or tying, agreements were unlawful as unreasonable restraints of trade in violation of section I of the Sherman Act, the district court granted the government\u27s motion for summary judgment. On appeal, held, affirmed, three justices dissenting and one justice not sitting. Tying agreements are per se unreasonable whenever a party has sufficient economic power with respect to the tying product (land) to restrain appreciably free competition in the market for the tied product (transportation) and a not insubstantial amount of interstate commerce is affected. Northern Pacific Ry. Co. v. United States, 356 U.S. I (1958)
THE LOW-TEMPERATURE NUCLEAR SPIN EQUILIBRIUM OF H IN COLLISIONS WITH H
No full textAuthor Institution: Max-Planck-Institut fur Kernphysik, 69117 Heidelberg, Germany; Department of Chemistry, University of Illinois, Urbana, IL, 61801; I. Physikalisches Institut, Universitat zu Koln, 50937 Koln, GermanyObservations of H in diffuse molecular clouds have revealed that the ratio of its \textit{ortho} and \textit{para} nuclear spin modifications are not in thermodynamic equilibrium with the environment. This discrepancy could be explained if the reaction H + H H + H, which interconverts the nuclear spin modifications of H, has a nonthermal outcome at low temperatures, possibly arising from nuclear spin selection rules on systems of identical fermions. While the nuclear spin dependence of this reaction has previously been investigated experimentally, the prior measurements were limited to temperatures above 130 K, well above the 50-70 K typical of diffuse molecular clouds. To investigate whether the outcome of the H + H reaction is nonthermal, H ions were allowed to interact with H in the temperature-controlled environment of a 22-pole radiofrequency ion trap, and the relative abundances of \textit{ortho}- and \textit{para}-H at steady state were measured using action spectroscopy. By carefully controlling the \textit{ortho}:\textit{para} ratio of the H samples in conjunction with the ion trap temperature, the outcome of the reaction was observed to be close to thermodynamic equilibrium over the temperature range of 45-100 K. Thus, the nonequilibrium \textit{ortho}:\textit{para} ratio of H observed in diffuse molecular clouds does not arise from a nonthermal outcome of the H + H reaction at low temperature. This implies that the origin of the discrepancy lies in the respective formation and destruction mechanisms of H
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Report on Applicability of Residential Ventilation Standards in California
No full textThe California Energy Commission is considering updating its requirements for residential ventilation in the next round of its energy code, known as ''Title 24''. This report contains recommendations for potential changes to the code. These recommendations must be further developed into specific wording before they can be formally considered. Residential ventilation standards always address local and whole-house ventilation rates and some basic source control requirements, but there are many interactions with building systems that must also be considered. McKone and Sherman [8] laid out a set of additional issues that should be addressed before any specific changes to the code should be made. Those key issues included the following: Adventitious Air Flow; Air Distribution; Filtration and Air Cleaning; Occupant Acceptability and Control; Outdoor Air; Peak Demand; Unusual Sources and High-Polluting Events; and Window Operation. McWilliams and Sherman reviewed the literature on residential ventilation and in particular these key issues. They also reviewed codes, standards and guidelines relevant to residential ventilation. That literature serves as the technical basis for this report
CHEMICAL PROBING SPECTROSCOPY OF H IN A CRYOGENIC RADIOFREQUENCY TRAP
No full textH. Kreckel, D. Bing, S. Reinhardt, A. Petrignani, Max Berg, and A. Wolf, J. Chem. Phys. 129, 164312 (2008)Author Institution: Max-Planck-Institut fur Kernpysik, Saupfercheckweg 1, 69117 Heidelberg, GermanyThe H molecular ion is a key species for the chemistry of the interstellar medium. Being the simplest polyatomic ion it also serves as a benchmark system for quantum chemistry calculations. Due to the absence of a permanent dipole moment and since no stable electronically excited states are known, spectroscopy is restricted to vibrational transitions in the infrared. To date more than 800 transitions covering states up to 13\,600\,cm above the ground state have been observed. Nevertheless, for a better understanding of H dissociation and dynamics, it is necessary to extend that range considerably towards the dissociation limit of ~35\,000\,cm. We have developed a chemical probing technique that is able to probe high-lying H states with unprecedented sensitivity. The H ions are buffer-gas cooled in a radiofreqeuncy ion trap at 55\,K. Argon is let in as a probe gas and laser transitions between 11\,330 and 13\,300\,cm trigger the formation of ArH ions which are detected by a quadrupole mass spectrometer. Here, we report the detection of the weakest H transitions observed to date and discuss the possible extension of the scheme into visible wavelengths and beyond
A model-independent Dalitz plot analysis of B±→DK± with D→K0Sh+h− (h=π,K) decays and constraints on the CKM angle γ
No full textA binned Dalitz plot analysis of B ±→DK ± decays, with D→KS0π+π- and D→KS0K+K-, is performed to measure the CP-violating observables x ± and y ± which are sensitive to the CKM angle γ. The analysis exploits 1.0 fb -1 of data collected by the LHCb experiment. The study makes no model-based assumption on the variation of the strong phase of the D decay amplitude over the Dalitz plot, but uses measurements of this quantity from CLEO-c as input. The values of the parameters are found to be x -=(0.0±4.3±1.5±0.6)×10 -2, y -=(2.7±5.2±0.8±2.3)×10 -2, x +=(-10.3±4.5±1.8±1.4)×10 -2 and y +=(-0.9±3.7±0.8±3.0)×10 -2. The first, second, and third uncertainties are the statistical, the experimental systematic, and the error associated with the precision of the strong-phase parameters measured at CLEO-c, respectively. These results correspond to γ=(44-38+43)°, with a second solution at γ→γ+180°, and r B=0.07±0.04, where r B is the ratio between the suppressed and favoured B decay amplitudes
Search for direct CP violation in D0→h−h+ modes using semileptonic B decays
No full textA search for direct CP violation in D0 → h-h+ (where h = K or π) is presented using data corresponding to an integrated luminosity of 1.0 fb-1 collected in 2011 by LHCb in pp collisions at a centre-of-mass energy of 7 TeV. The analysis uses D0 mesons produced in inclusive semileptonic b-hadron decays to the D0μX final state, where the charge of the accompanying muon is used to tag the flavour of the D0 meson. The difference in the CP-violating asymmetries between the two decay channels is measured to be ΔACP = ACP(K-K+) - ACP(π-π+) = (0.49± 0.30 (stat) ± 0.14 (syst))%
Spectroscopic detection of an arylchlorocarbene-ethyl acetate carbonyl ylide and subsequent oxirane formation
No full textLaser flash photolysis of 3-chloro-3-(p-nitrophenyl)diazirine (1) generates the corresponding ground-state singlet carbene (lambda-max = 310 nm), which reacts with ethyl acetate to form a carbonyl ylide of the ester (lambda-max = 490 nm). The absolute rate constant for ylide formation in CH2Cl2 is k = (2.85 +/- 0.17) X 10(6) M-1 s-1. Subsequent cyclization of the ylide to the corresponding oxirane (lambda-max = 350 nm) occurs with a rate constant of 1.26 x 10(6) S-1 (21-degrees-C) in ethyl acetate with Arrhenius activation parameters for oxirane formation of E(act) = 6.68 +/- 0.19 kcal/mol and log A (s-1) = 11.08 +/- 0.15. The carbonyl ylide is also intercepted with the dipolarophile, diethyl fumarate, with a rate constant of (1.04 +/- 0.07) x 10(7) M-1 s-1. Additionally, solvent polarity effects on (p-nitrophenyl)chlorocarbene reactivity and spectroscopic evidence of oxirane formation (lambda-max = 350 nm) from the related acetone ylide of (p-nitrophenyl)chlorocarbene are presented.PT: J; CR: BONNEAU R, 1989, J CHEM SOC CHEM COMM, P510 BONNEAU R, 1990, J AM CHEM SOC, V112, P744 IBATA T, 1987, CHEM LETT, V28, P2135 LIU MTH, 1972, CAN J CHEM, V50, P3009 LIU MTH, 1987, TETRAHEDRON LETT, V28, P1011 LIU MTH, 1990, J CHEM SOC CHEM COMM, P1482 NAGARAJAN V, 1985, J PHYS CHEM-US, V89, P2330 PAUL H, 1978, J AM CHEM SOC, V100, P4520 PLATZ MS, COMMUNICATION REICHARDT C, 1988, SOLVENTS SOLVENT EFF, P352 SOUNDARARAJAN N, 1988, J AM CHEM SOC, V110, P7143 SOUNDARARAJAN N, 1988, TETRAHEDRON LETT, V29, P3419; NR: 12; TC: 14; J9: J AMER CHEM SOC; PG: 4; GA: GB298Source type: Electronic(1
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