3,289 research outputs found
Conceptual Trends and Implications for Risk Research. Report of the Task Force Meeting: Risk and Policy Analysis Under Conditions of Uncertainty, November 25-27,1985
The Task Force focused on the uncertainties in decision systems for choosing or modifying technologies intended to improve human well-being. The challenge was to delineate an international research agenda to assist communities to venture into the future with greater confidence in technological innovation.
The Task Force recommended research in three interrelated areas: (1) Protocols -- Development of procedural advice for the integrated assessment of the contribution of technologies to environmental and economic achievements, and the associated uncertainties. (2) Case Studies -- Integrated assessments involving local or regional clusters of technologies and decision-making bodies, and investigation of ecosystem effects, economic effects, and effects on human well-being, as well as the structure and performance of institutions. (3) Educational Materials -- Development of educational materials to support integrated assessments
High-Excitation Hole States in the (p,d) Reaction
This work was supported by National Science Foundation Grant PHY 76-84033 and Indiana Universit
Specific heat study of the Na(0.3)CoO(2).1.3H(2)O superconductor: influence of the complex chemistry
We report results of specific heat measurements on polycrystalline samples of
the layered superconductor, Na(0.3)CoO(2).1.3H(2)O. The electronic contribution
to the specific heat, gamma, is found to be 12.2 mJ/mol-K2. The feature at the
superconducting transition is rather sharp, becoming broad and strongly
suppressed in an applied magnetic field. The data indicate a residual normal
state electronic specific heat at low temperatures, implying that there is a
sizable population of normal state electrons in the samples even below Tc.
Inhomogeneity in the Na content, to which the superconducting state is
exquisitely sensitive, appears to be the most likely explanation for these
results. These results further indicate that special sample handling is
required for an accurate characterization of the superconducting state in this
material.Comment: publication information adde
First-principles study of stability and vibrational properties of tetragonal PbTiO_3
A first-principles study of the vibrational modes of PbTiO_3 in the
ferroelectric tetragonal phase has been performed at all the main symmetry
points of the Brillouin zone (BZ). The calculations use the local-density
approximation and ultrasoft pseudopotentials with a plane-wave basis, and
reproduce well the available experimental information on the modes at the Gamma
point, including the LO-TO splittings. The work was motivated in part by a
previously reported transition to an orthorhombic phase at low temperatures
[(J. Kobayashi, Y. Uesu, and Y. Sakemi, Phys. Rev. B {\bf 28}, 3866 (1983)]. We
show that a linear coupling of orthorhombic strain to one of the modes at Gamma
plays a role in the discussion of the possibility of this phase transition.
However, no mechanical instabilities (soft modes) are found, either at Gamma or
at any of the other high-symmetry points of the BZ.Comment: 8 pages, two-column style with 3 postscript figures embedded. Uses
REVTEX and epsf macros. Also available at
http://www.physics.rutgers.edu/~dhv/preprints/index.html#ag_pbt
Deep Hole States in the Mirror Nuclei 23-Mg and 23-Na
This work was supported by National Science Foundation Grant PHY 76-84033 and Indiana Universit
High Excitation Hole States in the (p,d) Reaction
This work was supported by National Science Foundation Grant PHY 75-00289 and Indiana Universit
High-Excitation Hole States in the 24-Mg(p,d) Reaction
This work was supported by National Science Foundation Grants PHY 76-84033A01, PHY 78-22774, and Indiana Universit
Supporting the learning of deaf students in higher education: a case study at Sheffield Hallam University
This article is an examination of the issues surrounding support for the learning of deaf students in higher education (HE). There are an increasing number of deaf students attending HE institutes, and as such provision of support mechanisms for these students is not only necessary but essential. Deaf students are similar to their hearing peers, in that they will approach their learning and require differing levels of support dependant upon the individual. They will, however, require a different kind of support, which can be technical or human resource based. This article examines the issues that surround supporting deaf students in HE with use of a case study of provision at Sheffield Hallam University (SHU), during the academic year 1994-95. It is evident that by considering the needs of deaf students and making changes to our teaching practices that all students can benefit
Chemical Instability of the Cobalt Oxyhydrate Superconductor under Ambient Conditions
The layered sodium cobalt oxyhydrate superconductor Na0.3CoO2*1.4H2O is shown
through X-ray diffraction and thermogravimetric studies to be one of a series
of hydrated phases of Na0.3CoO2. Further, it is shown that the material is
exceptionally sensitive to both temperature and humidity near ambient
conditions, easily dehydrating to a non-superconducting lower hydrate. The
observation of this stable lower hydrate with c=13.8 angstroms implies that the
superconductivity turns on in this system between CoO2 layer spacings of 6.9
and 9.9 angstroms at nominally constant chemical doping.Comment: 10 pages and 4 figure
Keratoacanthoma management: results of a survey of UK dermatologists and surgeons.
Distinction of keratoacanthoma (KA) from squamous cell carcinoma (SCC) is challenging. Management is controversial, with some advocating prompt surgical excision and others monitoring to allow for spontaneous resolution(1) . The controversy is compounded by rare reports of metastasis(2) . And yet the benign natural history of KA is supported by various studies, including a systematic review of 455 cases with no cases of metastasis or death(1) , and observational studies confirming spontaneous resolution(1)
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