1,392 research outputs found
Pearl farming as a sustainable development path
For centuries, wild pearl oysters and mussels were fished in the quest for natural pearls and shell material. This eventually led to the drastic overexploitation of oyster stocks in many areas of the globe.1 Scientific innovation and entrepreneurship eventually unearthed a solution: Researchers discovered a way for humans to farm pearl oysters and induce the formation of a cultured pearl. A century after this discovery, many pearl farming regions are vulnerable to climate change and coral and coastal habitat destruction. Pearl farming might provide a win-win opportunity for such communities
Discussion on a new model for the Hercynian Orogen of Gondwana France and Iberia by D. Shelley & G. Bossière.
In spite of numerous studies, the geodynamic evolution of the Hercynian Orogeny of Western Europe is still controversial. In a recent paper, Shelley and Bossière (2000) propose that the Hercynian Orogeny in Iberia and France was a ‘collage' of distinct fault-bounded ‘terranes' developed during a major dextral wrenching of more than 2000 km. This interpretation is in line with that already proposed by Badham (1982) but is at variance with most other published models that emphazise tangential tectonics, that is to say thrusting and collision tectonics driven by oceanic and continental subduction (e.g. Matte; Ledru; Dias and Faure and references therein). The Shelley and Bossière model has been criticized for parts dealing with the Iberian branch of the orogen by Pereira and Silva (2001). In the following, we shall comment on the strike-slip model for the S. Armorican branch of the belt, on the basis of first-hand geological data aquired from the SE part of the Armorican Massif ( Cartier and Cartier) and general considerations on the Hercynian Belt
Predicted Infrared and Raman Spectra for Neutral Ti_8C_12 Isomers
Using a density-functional based algorithm, the full IR and Raman spectra are
calculated for the neutral Ti_8C_12 cluster assuming geometries of Th, Td, D2d
and C3v symmetry. The Th pentagonal dodecahedron is found to be dynamically
unstable. The calculated properties of the relaxed structure having C3v
symmetry are found to be in excellent agreement with experimental gas phase
infrared results, ionization potential and electron affinity measurements.
Consequently, the results presented may be used as a reference for further
experimental characterization using vibrational spectroscopy.Comment: 6 pages, 5 figures. Physical Review A, 2002 (in press
Comparison of four-times-a-day and twice-a-day dosing regimens in subjects requiring 1200 μg or less of budesonide to control mild to moderate asthma
AbstractThe aim of this study was to compare the efficacy, compliance and side-effects of budesonide administered twice daily (b.d.) and four times a day (q.d.) with a Turbuhaler® device in asthmatic subjects requiring ≤ 1200 μg daily. The randomized, parallel group study design included a 2-week baseline period followed by a 6–12-month treatment period. Subjects were assessed at regular intervals in hospital through FEV1, PC20 methacholine, adrenal function and throat swabs. They were asked to record their symptoms and PEF values morning and evening at home. An asthmatic flare-up, which was the main outcome resulting in a patient's termination of the study, was defined beforehand as (a) 25% or greater diurnal variability in PEF for 2 consecutive days, and/or (b) nocturnal awakenings due to asthma symptoms 2 days or more in the same week and/or (c) an increase (doubling or more) in the need for inhaled bronchodilator 2 days in the same week.Fifty-eight adult asthmatic subjects (20 males and 38 females) entered the study, one-half being randomly assigned to the b.d. regimen and one-half to the q.d. regimen. Fourteen subjects were on 400 μg, 15 subjects on 800 μg and 29 subjects on 1200 μg of budesonide daily. Seventeen flare-ups were recorded in the b.d. regimen group as opposed to 11 in the q.d. regimen (P=0·05), significant differences being found in the 800 and 1200 μg groups (a total of 13 flare-ups in the b.d. group and eight flare-ups in the q.d. group for the two doses, P=0·01). Kaplan-Meier survival analysis yielded similar results. There was no significant difference in FEV1, PC20 or cortisol levels during the study on either regimen. Throat symptoms and growth of Candida albicans were more common in the q.d. group. Compliance assessed by the number of times the Turbuhaler® device was actuated was significantly better in the b.d. group (95%) as compared with the q.d. group (83%). To conclude, administering inhaled budesonide with a Turbuhaler® device on a q.d. basis results in fewer flare-ups in spite of less satisfactory compliance and more common, local side-effects than on a b.d. regimen at daily doses of 800 and 1200 μg
A different look at the spin state of Co ions in CoO pyramidal coordination
Using soft-x-ray absorption spectroscopy at the Co- and O- edges,
we demonstrate that the Co ions with the CoO pyramidal
coordination in the layered SrCoOCl compound are unambiguously in the
high spin state. Our result questions the reliability of the spin state
assignments made so far for the recently synthesized layered cobalt
perovskites, and calls for a re-examination of the modeling for the complex and
fascinating properties of these new materials.Comment: 5 pages 3 figure
The -genus and a regularization of an -equivariant Euler class
We show that a new multiplicative genus, in the sense of Hirzebruch, can be
obtained by generalizing a calculation due to Atiyah and Witten. We introduce
this as the -genus, compute its value for some examples and
highlight some of its interesting properties. We also indicate a connection
with the study of multiple zeta values, which gives an algebraic interpretation
for our proposed regularization procedure.Comment: 14 pages; version to appear in J. Phys.
Construction of nonsingular cosmological solutions in string theories
We study nonsingular cosmological scenarios in a general -dimensional
string effective action of the dilaton-modulus-axion system in the presence of
the matter source. In the standard dilatonic Brans-Dicke parameter
() with radiation, we analytically obtain singularity-free bouncing
solutions where the universe starts out in a state with a finite curvature and
evolves toward the weakly coupled regime. We apply this analytic method to the
string-gas cosmology including the massive state in addition to the leading
massless state (radiation), with and without the axion. We numerically find
bouncing solutions which asymptotically approach an almost radiation-dominant
universe with a decreasing curvature irrespective of the presence of the axion,
implying that inclusion of the matter source is crucial for the existence of
such solutions for . In the theories with , it is
possible to obtain complete regular bouncing solutions with a finite dilaton
and curvature in both past and future asymptotics for the general dimension,
. We also discuss the case where dilatonic higher-order corrections are
involved to the tree-level effective action and demonstrate that the presence
of axion/modulus fields and the matter source does not significantly affect the
dynamics of the dilaton-driven inflation and the subsequent graceful exit.Comment: 27 pages, 6 eps figure
Annual Survey of Virginia Law: Employment Law
This survey covers legislative and judicial developments in Virginia employment law between June 1986 and June 1987. It does not address the workers\u27 compensation and unemployment compensation statutes but focuses on state labor and fair employment laws and the employment-at-will doctrine
Nature of singularities in anisotropic string cosmology
We study nature of singularities in anisotropic string-inspired cosmological
models in the presence of a Gauss-Bonnet term. We analyze two string gravity
models-- dilaton-driven and modulus-driven cases-- in the Bianchi type-I
background without an axion field. In both scenarios singularities can be
classified in two ways- the determinant singularity where the main determinant
of the system vanishes and the ordinary singularity where at least one of the
anisotropic expansion rates of the Universe diverges. In the dilaton case,
either of these singularities inevitably appears during the evolution of the
system. In the modulus case, nonsingular cosmological solutions exist both in
asymptotic past and future with determinant and D=2, respectively.
In both scenarios nonsingular trajectories in either future or past typically
meet the determinant singularity in past/future when the solutions are
singular, apart from the exceptional case where the sign of the time-derivative
of dilaton is negative. This implies that the determinant singularity may play
a crucial role to lead to singular solutions in an anisotropic background.Comment: 21 pages, 8 figure
A Physicist's Proof of the Lagrange-Good Multivariable Inversion Formula
We provide yet another proof of the classical Lagrange-Good multivariable
inversion formula using techniques of quantum field theory.Comment: 9 pages, 3 diagram
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