30,711 research outputs found

    An alternative method to access diverse N,N′-diquaternised-3,3′-biquinoxalinium “biquinoxen” dications

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    An alternative synthetic route for the design of N,N′-diquaternised-3,3′-biquinoxalinium “biquinoxen” dications is reported, involving oxidative radical coupling of dithionite reduced quinoxaline quaternary salts. Although the reaction is not regioselective, leading to relatively modest yields (up to 32%), the advantages of this new synthetic protocol lie in a simple potentially gram scale synthesis using inexpensive easily accessible reagents with no metal catalysts and no purification steps. Thus whereas the method reported previously to access the N,N′-dimethyl-3,3′-biquinoxalinium, “methylbiquinoxen” precursor gave higher yield than the new method reported here, this new method avoids the limitation of using scarce oxonium reagents. Overall, the new protocol is a robust synthetic strategy which offers new design possibilities

    Neutrino interactions in neon-hydrogen at high energy

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    Status and capabilities of sonic boom simulators

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    The current status and capabilities of sonic boom simulators which might be used in future studies of the effects of sonic boom on people, animals, or structures is summarized. The list of candidate simulators is based on a literature search which was confined to the United States and Canada. Some of the simulators are fully operational, others could be made operational with a modest investment, and still others would require a major investment. For the sake of the completeness, some simulators which were the subject of a previous review, but which no longer exist, are also included herein

    Effects of conversation interference on annoyance due to aircraft noise

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    The annoyance and interference effects of aircraft flyover noise on face to face conversation were investigated. Twenty 5 minute sessions, each composed of three flyovers, were presented to each of 20 pairs of female subjects in a simulated living room. Flyovers varied in peak noise level (55-79 dB, A-weighted) and spectrum (low or high frequency components). Subjects engaged in conversation for 10 sessions and in reverie for the other 10 sessions, and completed subjective ratings following every session. Annoyance was affected by noise level, but was not significantly different for the two activities of reverie and conversation. A noise level of 77 db was found unacceptable for conversation by 50 percent of the subjects. Conversation interference was assessed by incidence of increased vocal effort and/or interruption of conversation during flyovers. Although conversation interference increased with noise level, the conversation interference measures did not improve prediction of individual annoyance judgments

    SAM 2 measurements of the polar stratospheric aerosol. Volume 9: October 1982 - April 1983

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    The Stratospheric Aerosol Measurement (SAM) II sensor aboard Nimbus 7 is providing 1.0 micron extinction measurements of Antarctic and Arctic stratospheric aerosols with a vertical resolution of 1 km. Representative examples and weekly averages including corresponding temperature profiles provided by NOAA for the time and place of each SAM II measurement are presented. Contours of aerosol extinction as a function of altitude and longitude or time are plotted, and aerosol optical depths are calculated for each week. Typical values of aerosol extinction and stratospheric optical depth in the Arctic are unusually large due to the presence of material from the El Chichon volcano eruption in the Spring of 1982. For example, the optical depth peaked at 0.068, more than 50 times background values. Typical values of aerosol extinction and stratospheric optical depth in the Antarctic varied considerably during this period due to the transport and arrival of the material from the El Chichon eruption. For example, the stratospheric optical depth varied from 0.002 in October 1982, to 0.021 in January 1983. Polar stratospheric clouds were observed during the Arctic winter, as expected. A representative sample is provided of the ninth 6-month period of data to be used in atmospheric and climatic studies

    Thermocouple installation

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    A thermocouple assembly which includes a plug having a pair of small diameter holes near one end thereof which are spaced a small distance apart to leave a thin quantity of plug material between the holes is presented. There are a pair of thermocouple wires extending through the different holes and with the outer ends of the wires joined to the thin quantity of plug material which lies between the holes to form a thermocouple junction

    Shaking off the cloak of ‘certainty’ and embracing ethical dilemmas in baby rooms research

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    For a decade, we (the authors) have been actively engaged in funded research about Early Childhood Education and Care (ECEC) for babies and toddlers. In all cases, our work was approved by a Research Ethics Committee (REC). This scrutiny process provides an important mechanism for encouraging researchers to consider carefully the impact of their intentions and for protecting research participants from harm. But it can be simplistic in its requirements, its application and its conceptualisations of research relationships, procedures and outcomes. This article is not concerned with the shortcomings of RECs; instead, we consider some of the situated and relational ethical considerations that we encountered and which, in our experience, rarely surface in applications for ethical approval. We acknowledge that the very act of researching can do harm or lead to unintended consequences. Through our work, we became aware that research can produce results that may be unpalatable to the researchers and / or the participants. We have used Tronto’s (2013) five elements of an Ethic of Care to frame our post hoc reflections about researching the principles and practice of early childhood education and care (ECEC) for babies from birth to two in England. We employ the term, ‘palimpsest’ to convey our understanding of the ways in which multiple scripts, including research narratives, are layered upon those working with babies and young children. For example, the imposition of a national curriculum ‘script’ has the potential to usurp pre-existing professional beliefs, knowledge, understanding, identity and autonomy

    The impact of a high versus a low glycaemic index breakfast cereal meal on verbal episodic memory in healthy adolescents

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    In this study, healthy adolescents consumed a) a low glycaemic index (G.I.) breakfast cereal meal, or b) a high G.I. breakfast cereal meal, before completing a test of verbal episodic memory in which the memory materials were encoded under conditions of divided attention. Analysis of remembering/forgetting indices revealed that the High G.I. breakfast group remembered significantly more items relative to the Low G.I. breakfast group after a long delay. The superior performance observed in the High G.I. group, relative to the Low G.I. group, may be due to the additional glucose availability provided by the high G.I. meal at the time of memory encoding. This increased glucose availability may be necessary for effective encoding under dual task conditions
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