1,998 research outputs found

    Thermal performance of a naturally ventilated building using a combined algorithm of probabilistic occupant behaviour and deterministic heat and mass balance models

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    This study explores the role of occupant behaviour in relation to natural ventilation and its effects on summer thermal performance of naturally ventillated buildings. We develop a behavioural algorithm (the Yun algorithm) representing probablistic occupant behaviour and implement this within a dynamic energy simulation tool. A core of this algorithm is the use of Markov chain and Monte Carlo methods in order to integrate probablistic window use models into dynamic energy simulation procedures. The comparison between predicted and monitored window use patterns shows good agreement. Performance of the Yn algorithm is demonstrated for active, medium and passive window users and a range of office constructions. Results indicate, for example, that in some cases, the temperature of an office occupied by the active window user in summer is up to 2.6ÂșC lower than that for the passive window user. A comparison is made with results from an alernative bahavioural algorithm developed by Humphreys [H.B. Rijal, P. Tuohy, M.A. Humphreys, J.F. Nicol, A. Samual, J. Clarke, Using results from field surveys to predict the effect of open windows on thermal comfort and energy use in buildings, Energy and Buildings 39(7)(2007) 823-836.]. In general, the two algorithms lead to similar predictions, but the results suggest that the Yun algorithm better reflects the observed time of day effects on window use (i.e. the increased probability of action on arrival)

    Synthesis and Reactivity of Tricarbonyl(1-ethoxy-carbonyl-2-methylpentadienyl)iron(1+) Cation

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    The title cation was prepared in two steps from the known (ethyl 3-methyl-6-oxo-2,4-hexadienoate)Fe(CO)3. Reation of the cation with NaBH3CN, methyl cuprate, phthalimide, water, PPh3, or malonate anions gave predominantly the products from nucleophilic attack at the C5 pentadienyl carbon

    Iron-mediated Preparation of Vinylcyclopropanes. Scope, Mechanism, and Applications

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    The addition of stabilized carbon nucleophiles to tricarbonyl(1-methoxycarbonylpentadienyl)iron(1+) cation (1a) proceeds via attack at C2 on the face of the ligand opposite the Fe(CO)3 group to generate tricarbonyl(pentenediyl)iron complexes 2. Oxidation of complexes 2 affords vinylcyclopropanecarboxylates in good yield. In general, the relative stereochemistry about the cyclopropane ring reflects reductive elimination with retention of configuration. In cases where the C2 substituent is bulky (i.e., 2b) the major cyclopropane product 9b represents ring closure with inversion at C3. A mechanism involving π−σ−π rearrangement of the initially oxidized (pentenediyl)iron species is proposed to account for these results. Experiments which probe the stereochemistry of deuterium labeling in the vinyl group of the vinylcyclopropanecarboxylate products were carried out, and these results are consistent with the proposed mechanism. This methodology for the preparation of vinylcyclopropanecarboxylates was applied to the synthesis of 2-(2‘-carboxycyclopropyl)glycines (+)-22 and (−)-23 and the cyclopropane triester (−)-26

    What determines social service workers’ wages: A cross-country analysis using a Luxembourg Income Study

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    The study is aimed at exploring the influencing factor of wages among social service workers (SSWs) through a cross-country analysis. Using Luxembourg Income Study data, two aspects are emphasised: first, the trends and patterns of wage levels among SSWs. Second, the determining factors that influence their low wages at a cross-national level and how those factors are intersectionally intertwined to exacerbate the wage level. Three significant findings are confirmed: a universal gendered wage gap; a more significant wage gap for those on part-time and/or fractured contracts and employed in the private sector; and a substantial association between a higher education and higher wages. Two policy concerns are raised for discussion: first, tackling the gendered wage gap and ensuring more secure employment, and a guaranteed living wage for those employed in the private sector. Second, enhancing the professionalism for empowering their effective choices in the labour market is essential [148 words]

    Development of Organoiron Methodology for Preparation of the Polyene Natural Product Macrolactin A

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    Methodology for the synthesis of the C7–C13 segment (19) and C14–C24 segment (41) of macrolactin A have been developed. Dicarbonyl(methyl 7-nitro-2E,4Z-heptadienoate)triphenylphosphineiron (19) is prepared by nucleophilic addition to a (1-methoxycarbonylpentadienyl)iron cation. The C23 stereocenter of 41 is established by introduction of a C20 stereocenter, chirality transfer from C20 to C23 followed by (diene)iron mediated selective ionic reduction of the C20 hydroxyl. The C15 stereocenter may be established by nitrile oxide–olefin cyclocondensation

    Bristles reduce the force required to ‘fling’ wings apart in the smallest insects

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    ABSTRACT The smallest flying insects commonly possess wings with long bristles. Little quantitative information is available on the morphology of these bristles, and their functional importance remains a mystery. In this study, we (1) collected morphological data on the bristles of 23 species of Mymaridae by analyzing high-resolution photographs and (2) used the immersed boundary method to determine via numerical simulation whether bristled wings reduced the force required to fling the wings apart while still maintaining lift. The effects of Reynolds number, angle of attack, bristle spacing and wing–wing interactions were investigated. In the morphological study, we found that as the body length of Mymaridae decreases, the diameter and gap between bristles decreases and the percentage of the wing area covered by bristles increases. In the numerical study, we found that a bristled wing experiences less force than a solid wing. The decrease in force with increasing gap to diameter ratio is greater at higher angles of attack than at lower angles of attack, suggesting that bristled wings may act more like solid wings at lower angles of attack than they do at higher angles of attack. In wing–wing interactions, bristled wings significantly decrease the drag required to fling two wings apart compared with solid wings, especially at lower Reynolds numbers. These results support the idea that bristles may offer an aerodynamic benefit during clap and fling in tiny insects

    Impact of time to treatment of oseltamivir on influenza hospitalization cost among Korean children

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    BackgroundAlthough oseltamivir is a common influenza treatment, there is a lack of data on the economic benefits of timely oseltamivir treatment.MethodsFrom February 2004 through June 2007, 116 hospitalized children ≀15 years of age with laboratory‐confirmed influenza who received oseltamivir were identified via retrospective medical chart review. Demographic, clinical, and cost data were abstracted and multivariate linear regression was used to assess the association between oseltamivir time to treatment and treatment‐related costs among hospitalized children with laboratory‐confirmed influenza.ResultsOverall, 28% (n = 33) of patients were treated with oseltamivir ≄day 3 of admission. Rapid influenza diagnostic test was used in a significantly lower proportion of patients treated with oseltamivir ≄day 3 of admission compared with those who received oseltamivir earlier. On multivariate linear regression, initiation of oseltamivir ≄day 3 of admission was associated with a 60.84% increase (95%CI: 32.59–95.11) in treatment‐related hospital costs, compared with initiation on admission.ConclusionDelayed initiation of oseltamivir was found to be associated with increased treatment‐related hospital costs among children hospitalized with laboratory‐confirmed influenza.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/111958/1/ped12526.pd
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