28,511 research outputs found
Killing vectors and anisotropy
We consider an action that can generate fluids with three unequal stresses
for metrics with a spacelike Killing vector. The parameters in the action are
directly related to the stress anisotropies. The field equations following from
the action are applied to an anisotropic cosmological expansion and an
extension of the Gott-Hiscock cosmic string
Phantom Accretion by Black Holes and the Generalized Second Law of Thermodynamics
The accretion of a phantom fluid with non-zero chemical potential by black
holes is discussed with basis on the Generalized Second Law of thermodynamics.
For phantom fluids with positive temperature and negative chemical potential we
demonstrate that the accretion process is possible, and that the condition
guaranteeing the positiveness of the phantom fluid entropy coincides with the
one required by Generalized Second Law. In particular, this result provides a
complementary confirmation that cosmological phantom fluids do not need to have
negative temperatures
85% efficiency for cw frequency doubling from 1.08 to 0.54 μm
Conversion efficiency of 85% has been achieved in cw second-harmonic generation from 1.08 to 0.54 μm with a potassium titanyl phosphate crystal inside an external ring cavity. An absolute comparison between the experimental data and a simple theory is made and shows good agreement
Production cross-sections and momentum distributions of fragments from neutron-deficient 36Ar at 1.05 A.GeV
We have measured production cross sections and longitudinal momentum
distributions of fragments from neutron-deficient 36Ar at 1.05 A.GeV. The
production cross-sections show excellent agreement with the predictions of the
semiempirical formula EPAX. We have compared these results, involving extremly
neutron deficient nuclei, with model calculations to extract informa tion about
the response of these models close to the driplines. The longitudinal momentum
distributions have also been extracted and are compared with the Goldhaber and
Morrissey systematics.Comment: 16 pages, 6 figure
Some addition formulae for Abelian functions for elliptic and hyperelliptic curves of cyclotomic type
We discuss a family of multi-term addition formulae for Weierstrass functions
on specialized curves of genus one and two with many automorphisms. In the
genus one case we find new addition formulae for the equianharmonic and
lemniscate cases, and in genus two we find some new addition formulae for a
number of curves, including the Burnside curve.Comment: 19 pages. We have extended the Introduction, corrected some typos and
tidied up some proofs, and inserted extra material on genus 3 curve
A Herschel Study of 24 micron-Selected AGNs and Their Host Galaxies
We present a sample of 290 24-micron-selected active galactic nuclei (AGNs)
mostly at z ~ 0.3 -- 2.5, within 5.2 square degrees distributed as 25' X 25'
fields around each of 30 galaxy clusters in the Local Cluster Substructure
Survey (LoCuSS). The sample is nearly complete to 1 mJy at 24 microns, and has
a rich multi-wavelength set of ancillary data; 162 are detected by Herschel. We
use spectral templates for AGNs, stellar populations, and infrared emission by
star forming galaxies to decompose the spectral energy distributions (SEDs) of
these AGNs and their host galaxies, and estimate their star formation rates
(SFRs), AGN luminosities, and host galaxy stellar masses. The set of templates
is relatively simple: a standard Type-1 quasar template; another for the
photospheric output of the stellar population; and a far infrared star-forming
template. For the Type-2 AGN SEDs, we substitute templates including internal
obscuration, and some Type-1 objects require a warm component (T > 50 K). The
individually Herschel- detected Type-1 AGNs and a subset of 17 Type-2 ones
typically have luminosities > 10^{45} ergs/s, and supermassive black holes of ~
3 X 10^8 Msun emitting at ~ 10% of the Eddington rate. We find them in about
twice the numbers of AGN identified in SDSS data in the same fields, i.e., they
represent typical high luminosity AGN, not an infrared-selected minority. These
AGNs and their host galaxies are studied further in an accompanying paper
A view from the watershed
International audiencePapers by H. L. Penman, H. C. Pereira, J. E. Nash and M. Nixon presented at a one-day Symposium to mark the opening of the Institute of Hydrology's new building in 1973 and reprinted from Institute of Hydrology Report No. 20
Efeito de agentes geleificantes alternativos no meio de cultura no cultivo in vitro de abacaxizeiro e bananeira.
Com este trabalho, objetivou-se avaliar a ação do ágar e sua substituição parcial e total pelo amido de mandioca na composição de meios de cultura de bananeira e abacaxizeiro. Gemas axilares de abacaxizeiro, cvs. Rio Branco e Quinari foram estabelecidas e avaliadas por quatro subcultivos quanto à multiplicação em meio de MS, suplementado com 2 mg.L-1 de BAP e 0,25 mg.L-1 de ANA, e os seguintes tratamentos: M1: ágar (5 g.L-1), M2: ágar (2,5 g.L-1) + fécula de mandioca (60 g.L-1), M3: fécula de mandioca (60 g.L-1), e M4: ágar (2,5 g.L-1) + fécula de mandioca (30 g.L-1). Num segundo experimento, por três subcultivos sucessivos brotações de bananeira da cv. Grand Naine foram avaliadas quanto à multiplicação em meio de cultura composto por: MM1: ágar (6 g.L-1) ; MM2: ágar (3 g.L-1) + fécula de mandioca (30 g.L-1); MM3: fécula de mandioca (60 g.L-1) e; MM4: meio de consistência líquida estacionário.Estes meios foram suplementados com 0, 2, 4 e 6 mg.L-1 de BAP. Para o abacaxizeiro, verificou-se quea substituição total do ágar pela fécula proporcionou resultados similares aos obtidos com o tratamento com ágar. Na combinação ágar + fécula os resultados foram inferiores aos obtidos com os solidificantes usados isoladamente. Para a bananeira, o uso isolado ou combinado da fécula com ágar não proporcionou melhora nas taxas de multiplicação. Os melhores resultados foram obtidos em meio com ágar e 2 mg.L-1 de BAP. O cultivo em meio líquido apresentou o menor índice de multiplicação
Impact of Combined Exercise on Chronic Obstructive Pulmonary Patients' State of Health
AIM: The aim of the study was to evaluate the effectiveness of a 10-week combined training programme (aerobic and strength exercise) compared to an aerobic training programme, and respiratory physiotherapy on COPD patients' health.
METHODS: Fifty subjects with moderate to severe COPD were randomly assigned to two groups. Combined group (CG, n=25) who underwent combined training, and aerobic group (AG, n=25) who underwent aerobic training. These were compared with fifty COPD subjects who underwent respiratory physiotherapy, breathing control and bronchial clearance techniques (RP group, n = 50). We evaluated health state through two questionnaires, St. George's Respiratory Questionnaire (SGRQ) and SF-36, at the beginning and at the end of the programme.
RESULTS: The CG group showed differences (p<0.0001) in modification rates in state of health compared to the AG and RP groups in the activity (64 ± 9%, 19 ± 7%, 1 ± 15%) , impact (35 ± 5%, 20 ± 18%, 1 ± 14%) and total (41 ± 9%, 26 ± 17%, 1 ± 15%) domains assessed by the SGRQ, and the physical function (109 ± 74%, 22 ± 12%, 0.1 ± 18%), physical role (52 ± 36%, 11 ± 15%, 1.3 ± 21%) and vitality (83 ± 39%, 14 ± 38%) domains assessed by SF-36.
CONCLUSION: These results suggest that combined training in subjects with COPD appears to be a more effective method, with better clinical changes, and improvements in health state perception
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