656 research outputs found

    The validity of weighted scoring evaluation techniques applied to design: studies in the appraisal of heating, ventilating and air conditioning systems for office buildings.

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    The common weighted scoring evaluation technique is presented by the design methods literature and by many practical guides as being an appropriate method for appraising different design solutions, however there are few critical assessments of the assumptions inherent in the method and no serious attempts to evaluate the validity of the technique as applied in a design context. This thesis presents a series of empirical studies and theoretical reviews which examine, in a logical sequence, aspects of the validity of weighted scoring techniques in the context of early stage heating, ventilating and air conditioning (HVAC) system design for office buildings. The nature of the HVAC design process is investigated, and in parallel with this a theoretical critique of the weighted scoring method as described in the design methods literature is conducted. It is found that the common approach to weighted scoring is invalid, raising concern over the indiscriminate use of such decision aids. However, a theoretically correct interpretation known as Multi-Attribute Value Theory (MAVT) is possible. It is also found that the method is not applicable to the selection of HVAC systems in general, but may be considered reasonably valid in more restricted tasks such as air conditioning system selection for a specific area in a building. While the MAVT models developed are judged to be reasonably valid, it is argued that their usefulness is debatable. If all the information on which to base the decision is available and the decision maker is reasonably skilled then MAVT will only improve decision making at the margin where the penalty for a wrong decision is less significant

    Pensions and the Labor Market

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    Employers typically view their investment in pension plans as a means of providing retirement income for their workers. Economists, on the other hand, view pension programs as a way to increase workplace productivity. Dorsey, Cornwell and Macpherson explore the theoretical and empirical basis for this perspective and, in the process, offer a complete and up-to-date discussion on the productivity theory of pensions.https://research.upjohn.org/up_press/1067/thumbnail.jp

    Piperazinyl quinolines as chemosensitizers to increase fluconazole susceptibility of Candida albicans clinical isolates

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    The effectiveness of the potent antifungal drug fluconazole is being compromised by the rise of drug-resistant fungal pathogens. While inhibition of Hsp90 or calcineurin can reverse drug resistance in Candida, such inhibitors also impair the homologous human host protein and fungal-selective chemosensitizers remain rare. The MLPCN library was screened to identify compounds that selectively reverse fluconazole resistance in a Candida albicans clinical isolate, while having no antifungal activity when administered as a single agent. A piperazinyl quinoline was identified as a new small-molecule probe (ML189) satisfying these criteria.National Institutes of Health (U.S.) (1 R03 MH086456-01

    Pensions and Productivity

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    Employers typically view their investment in pension plans as a means of providing retirement income for their workers. Economists, on the other hand, view pension programs as a way to increase workplace productivity. Dorsey, Cornwell and Macpherson explore the theoretical and empirical basis for this perspective and, in the process, offer a complete and up-to-date discussion on the productivity theory of pensions.https://research.upjohn.org/up_press/1067/thumbnail.jp

    Cardiovascular effects of serotonergic agents

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    Serotonin (5-hydroxytryptamine, 5-HT) is a neurotransmitter which exerts its cardiovascular effects predominantly by interaction with specific 5-HT1 and 5- HT2 receptors. The effects of serotonergic agents differ between in vivo and in vitro preparations and display wide inter-species variation. It is therefore impossible to extrapolate results from animal or in vitro studies to the clinical situation. The role of these two receptors has therefore been studied in patients with suspected coronary artery disease using 3 different 5-HT1 agonists and ketanserin, a 5-HT2 antagonist. Sumatriptan and naratriptan, 5-HT1B/D receptor agonists, vasoconstrict the systemic and pulmonary circulations. Sumatriptan-induced vasoconstriction appears more pronounced in the pulmonary circulation suggesting a greater density of 5-HT1 receptors in the pulmonary compared to the systemic circulation. Although left ventricular end diastolic pressure and pulmonary artery wedge pressure rose after sumatriptan, there was no change in peak rate of left ventricular pressure rise, indicating the absence of a negative inotropic action. Naratriptan, an analogue of sumatriptan, displayed no significant effect on coronary artery diameter, a finding previously noted with sumatriptan. Eletriptan, a selective 5-HT1D agonist with less 5-HT1B activity, had little vasoconstrictor effect on the systemic, pulmonary or coronary circulation perhaps suggesting that the 5-HT1B receptor subtype mediates vasoconstriction. The effect of sumatriptan on systolic time intervals and forearm blood flow was also assessed. The results suggest that STI's are of potential use in the non-invasive assessment of 5-HT1 agonists. No significant effect on forearm blood flow was observed but plasma noradrenaline levels fell after subcutaneous sumatriptan. Ketanserin, a 5-HT2 antagonist, acted as a vasodilator in the systemic and pulmonary circulation but failed to vasodilate the coronary arteries, presumably because the patients in this study had stable angina without platelet activation and therefore had low circulating levels of serotonin

    Electrochemistry at carbon nanotube forests : sidewalls and closed ends allow fast electron transfer

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    The electrochemical properties of the closed ends and sidewalls of pristine carbon nanotube forests are investigated directly using a nanopipet electrochemical cell. Both are shown to promote fast electron transfer, without any activation or processing of the carbon nanotube material required, in contrast to the current model in the literature

    Performance of the CMS Cathode Strip Chambers with Cosmic Rays

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    The Cathode Strip Chambers (CSCs) constitute the primary muon tracking device in the CMS endcaps. Their performance has been evaluated using data taken during a cosmic ray run in fall 2008. Measured noise levels are low, with the number of noisy channels well below 1%. Coordinate resolution was measured for all types of chambers, and fall in the range 47 microns to 243 microns. The efficiencies for local charged track triggers, for hit and for segments reconstruction were measured, and are above 99%. The timing resolution per layer is approximately 5 ns

    Performance and Operation of the CMS Electromagnetic Calorimeter

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    The operation and general performance of the CMS electromagnetic calorimeter using cosmic-ray muons are described. These muons were recorded after the closure of the CMS detector in late 2008. The calorimeter is made of lead tungstate crystals and the overall status of the 75848 channels corresponding to the barrel and endcap detectors is reported. The stability of crucial operational parameters, such as high voltage, temperature and electronic noise, is summarised and the performance of the light monitoring system is presented
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