1,559 research outputs found
Franck-Condon Blockade in a Single-Molecule Transistor
We investigate vibron-assisted electron transport in single-molecule
transistors containing an individual Fe4 Single-Molecule Magnet. We observe a
strong suppression of the tunneling current at low bias in combination with
vibron-assisted excitations. The observed features are explained by a strong
electron-vibron coupling in the framework of the Franck-Condon model supported
by density-functional theory
Creating the ‘ethics industry': Mary Warnock, in vitro fertilization and the history of bioethics in Britain
Recent decades have seen a shift in the management and discussion of biomedicine. Issues once considered by doctors and scientists are now handled by a diverse array of participants, including philosophers, lawyers, theologians and lay representatives. This new approach, known as ‘bioethics', has become the norm in regulatory committees and public debate. In this article, I argue that bioethics emerged as a valued enterprise in Britain during the 1980s because it fulfilled, and linked, the concerns of several groups. My analysis centres on the moral philosopher Mary Warnock, who chaired a government inquiry into human fertilization and embryology between 1982 and 1984, and became a strong advocate of bioethics. I detail how Warnock's promotion of bioethics tallied with the Conservative government's desire for increased surveillance of hitherto autonomous professions – while fulfilling her own belief that philosophers should engage in public affairs. And I also show that Warnock simultaneously promoted bioethics to doctors and scientists as an essential safeguard against declining political and public trust. This stance, I argue, framed bioethics as a vital intermediary between politics, the public, and biomedicine, and explains the growth and endurance of what the Guardian identified as an ethics industry
Sodium Transport in Capillaries Isolated from Rat Brain
Brain capillary endothelial cells form a bloodbrain barrier (BBB) that appears to play a role in fluid and ion homeostasis in brain. One important transport system that may be involved in this regulatory function is the Na + ,K + -ATPase that was previously demonstrated to be present in isolated brain capillaries. The goal of the present study was to identify additional Na + transport systems in brain capillaries that might contribute to BBB function. Microvessels were isolated from rat brains and 22 Na + uptake by and efflux from the cells were studied. Total 22 Na + uptake was increased and the rate of 22 Na + efflux was decreased by ouabain, confirming the presence of Na + ,K + -ATPase in capillary cells. After inhibition of Na + ,K + -ATPase activity, another saturable Na + transport mechanism became apparent. Capillary uptake of 22 Na + was stimulated by an elevated concentration of Na + or H + inside the cells and inhibited by extracellular Na + , H + , Li + , and NH 4 + . Amiloride inhibited 22 Na + uptake with a K i between 10 −5 and 10 −6 M but there was no effect of 1 mM furosemide on 22 Na + uptake by the isolated microvessels. These results indicate the presence in brain capillaries of a transport system capable of mediating Na + / Na + and Na + /H + exchange. As a similar transport system does not appear to be present on the luminal membrane of the brain capillary endothelial cell, it is proposed that Na + /H + exchange occurs primarily across the antiluminal membrane.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/66187/1/j.1471-4159.1983.tb09065.x.pd
STELAR: An experiment in the electronic distribution of astronomical literature
STELAR (Study of Electronic Literature for Astronomical Research) is a Goddard-based project designed to test methods of delivering technical literature in machine readable form. To that end, we have scanned a five year span of the ApJ, ApJ Supp, AJ and PASP, and have obtained abstracts for eight leading academic journals from NASA/STI CASI, which also makes these abstracts available through the NASA RECON system. We have also obtained machine readable versions of some journal volumes from the publishers, although in many instances, the final typeset versions are no longer available. The fundamental data object for the STELAR database is the article, a collection of items associated with a scientific paper - abstract, scanned pages (in a variety of formats), figures, OCR extractions, forward and backward references, errata and versions of the paper in various formats (e.g., TEX, SGML, PostScript, DVI). Articles are uniquely referenced in the database by journal name, volume number and page number. The selection and delivery of articles is accomplished through the WAIS (Wide Area Information Server) client/server models requiring only an Internet connection. Modest modifications to the server code have made it capable of delivering the multiple data types required by STELAR. WAIS is a platform independent and fully open multi-disciplinary delivery system, originally developed by Thinking Machines Corp. and made available free of charge. It is based on the ISO Z39.50 standard communications protocol. WAIS servers run under both UNIX and VMS. WAIS clients run on a wide variety of machines, from UNIX-based Xwindows systems to MS-DOS and macintosh microcomputers. The WAIS system includes full-test indexing and searching of documents, network interface and easy access to a variety of document viewers. ASCII versions of the CASI abstracts have been formatted for display and the full test of the abstracts has been indexed. The entire WAIS database of abstracts is now available for use by the astronomical community. Enhancements of the search and retrieval system are under investigation to include specialized searches (by reference, author or keyword, as opposed to full test searches), improved handling of word stems, improvements in relevancy criteria and other retrieval techniques, such as factor spaces. The STELAR project has been assisted by the full cooperation of the AAS, the ASP, the publishers of the academic journals, librarians from GSFC, NRAO and STScI, the Library of Congress, and the University of North Carolina at Chapel Hill
Nephropathy in males and females with Fabry disease: cross-sectional description of patients before treatment with enzyme replacement therapy
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Repositioning of special schools within a specialist, personalised educational marketplace - the need for a representative principle
This paper considers how notions of inclusive education as defined in the United Nations Educational, Scientific and Cultural Organization (UNESCO) Salamanca Agreement (1994) have become dissipated, and can be developed and reframed to encourage their progress. It analyses the discourse within a range of academic, legal and media texts, exploring how this dissipation has taken place within the UK. Using data from 78 specialist school websites it contextualises this change in the use of the terms and ideas of inclusion with the rise of two other constructs, the 'specialist school' and 'personalisation'. It identifies the need for a precisely defined representative principle to theorise the type of school which inclusion aims to achieve, which cannot be subsumed by segregated providers. It suggests that this principle should not focus on the individual, but draw upon a liberal/democratic view of social justice, underlining inclusive education's role in removing social barriers that prevent equity, access and participation for all
Autism and the U.K. secondary school experience
This research investigated the self-reported mainstream school experiences of those diagnosed on the autistic spectrum compared with the typically developing school population. Existing literature identifies four key areas that affect the quality of the school experience for students with autism: social skills, perceived relationships with teaching staff, general school functioning, and interpersonal strengths of the young person. These areas were explored in a mainstream U.K. secondary school with 14 students with autism and 14 age and gender matched students without autism, using self-report questionnaires and semi-structured interviews. Quantitative analyses showed consistent school experiences for both groups, although content analysis of interview data highlighted some differences in the ways in which the groups perceive group work, peers, and teaching staff within school. Implications for school inclusion are discussed, drawing attention to how staff awareness of autism could improve school experience and success for students with autism attending mainstream schools
Impact of the Wiggler Coherent Synchrotron Radiation Impedance on the Beam Instability
Coherent Synchrotron Radiation (CSR) can play an important role by not only
increasing the energy spread and emittance of a beam, but also leading to a
potential instability. Previous studies of the CSR induced longitudinal
instability were carried out for the CSR impedance due to dipole magnets.
However, many storage rings include long wigglers where a large fraction of the
synchrotron radiation is emitted. This includes high-luminosity factories such
as DAPHNE, PEP-II, KEK-B, and CESR-C as well as the damping rings of future
linear colliders. In this paper, the instability due to the CSR impedance from
a wiggler is studied assuming a large wiggler parameter . The primary
consideration is a low frequency microwave-like instability, which arises near
the pipe cut-off frequency. Detailed results are presented on the growth rate
and threshold for the damping rings of several linear collider designs.
Finally, the optimization of the relative fraction of damping due to the
wiggler systems is discussed for the damping rings.Comment: 10 pages, 7 figure
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