8,660 research outputs found

    In the Wake of the Flood

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    Porous silica spheres as indoor air pollutant scavengers

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    Porous silica spheres were investigated for their effectiveness in removing typical indoor air pollutants, such as aromatic and carbonyl-containing volatile organic compounds (VOCs), and compared to the commercially available polymer styrene-divinylbenzene (XAD-4). The silica spheres and the XAD-4 resin were coated on denuder sampling devices and their adsorption efficiencies for volatile organic compounds evaluated using an indoor air simulation chamber. Real indoor sampling was also undertaken to evaluate the affinity of the silica adsorbents for a variety of indoor VOCs. The silica sphere adsorbents were found to have a high affinity for polar carbonyls and found to be more efficient than the XAD-4 resin at adsorbing carbonyls in an indoor environment

    A new mid-infrared map of the BN/KL region using the Keck telescope

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    We present a new mid-infrared (12.5micron) map of the BN/KL high-mass star-forming complex in Orion using the LWS instrument at Keck I. Despite poor weather we achieved nearly diffraction-limited images (FWHM = 0.38'') over a roughly 25'' X 25'' region centered on IRc2 down to a flux limit of ~250 mJy. Many of the known infrared (IR) sources in the region break up into smaller sub-components. We have also detected 6 new mid-IR sources. Nearly all of the sources are resolved in our mosaic. The near-IR source ''n'' is slightly elongated in the mid-IR along a NW--SE axis and perfectly bisects the double-peaked radio source ''L''. Source n has been identified as a candidate for powering the large IR luminosity of the BN/KL region (L = 10^5 L_sun). We postulate that the 12 micron emission arises in a circumstellar disk surrounding source n. The morphology of the mid-IR emission and the Orion ''hot core'' (as seen in NH_3 emission), along with the location of water and OH masers, is very suggestive of a bipolar cavity centered on source n and aligned with the rotation axis of the hypothetical circumstellar disk. IRc2, once thought to be the dominant energy source for the BN/KL region, clearly breaks into 4 sub-sources in our mosaic, as seen previously at 3.8 -- 5.0 micron. The anti-correlation of mid-IR emission and NH_3 emission from the nearby hot core indicates that the IRc2 sources are roughly coincident (or behind) the dense hot core. The nature of IRc2 is not clear: neither self-luminous sources (embedded protostars) nor external heating by source I can be definitively ruled out. We also report the discovery of a new arc-like feature SW of the BN object, and some curious morphology surrounding near-IR source ''t".Comment: To appear in The Astronomical Journal, July 2004 (16 pages, 7 figures

    Purposive models of legislative behavior

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    Memory: looking back and looking forward

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    This review brings together past and present achievements in memory research, ranging from molecular to psychological discoveries. Despite some false starts, major advances include our growing understanding of learning-related neural plasticity and the characterisation of different classes of memory. One striking example is the ability to reactivate targeted neuronal ensembles so that an animal will seemingly re-experience a particular memory, with the further potential to modify such memories. Meanwhile, human functional imaging studies can distinguish individual episodic memories based on voxel activation patterns. While the hippocampus continues to provide a rich source of information, future progress requires broadening our research to involve other sites. Related challenges include the need to understand better the role of glial-neuron interactions and to look beyond the synapse as the sole site of experience-dependent plasticity. Unmet goals include translating our neuroscientific knowledge in order to optimise learning and memory, especially amongst disadvantaged populations

    Toward a Theory of Legislative Decision

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    Recent developments in formal political analysis have spawned two seemingly related theories of democratic political processes. The more familiar of the two is the theory of electoral competition based on Downs' (1957) heuristics and greatly elaborated by Davis, Hinich and Ordeshook (1970), Kramer (1975), McKelvey (1976), and others. Somewhat less familiar (perhaps because the intellectual movement is less well integrated) is the theory of legislative decision which has grown from roots in game theory and the theory of social choice. Black (1958), Riker (1962), Plott (1967), Wilson (1969), Schwartz (1970), Kadane (1972), and several others have nurtured the rudimentary models which compose this theory

    The Constituency Service Basis of the Personal Vote for U.S. Representatives and British Members of Parliament

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    Under the guise of the "incumbency advantage" American research of the past decade has devoted heavy emphasis to what may be termed the "personal vote" in Congressional elections. Is this phenomenon a purely American one, or is it something susceptible to comparative treatment? This paper contrasts the personal vote in the 1980 U. S. House elections with that in the 1979 British General Election. The analysis utilizes data from surveys conducted by the Center for Political Studies and British Gallup, respectively, in combination with interviews of House AAs and British MPs and party agents whose constituencies fall in the sampling frames of the mass surveys. The analysis finds an incumbency advantage or personal vote in Britain, much weaker than that in the U. S., but of somewhat greater importance than is commonly believed, As in the U. S. constituency service appears to be an important component of the personal vote

    The Images of Incumbents in Great Britain and the United States

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    Incumbents in single member, simple plurality systems strive to develop name recognition and positive images of themselves. We propose to analyze the images that constituents in Great Britain and the United States have of their MPs and Congressmen and to measure the impact which incumbent activities have on those images. We also examine the normative expectations that constituents in both countries have of their representatives and how these expectations shape their evaluations. The data for this study comes from matching elite and voter surveys in Great Britain and the United States. Our results can be summarized as follows: 1) a large percentage of constituents in both countries believe that casework and protecting district interests are the most important functions of the representative; 2) those from working class, less well educated backgrounds are more inclined to prefer a service role for their representative than a policy role; 3) the evaluations that constituents have of their representatives reflects the importance of constituency service in their priorities as well; and 4) that representatives who undertake high levels of constituency service have better constituent images than other representatives
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