21,599 research outputs found
Investigations on the respiration of the Neotropical fish, Colossoma macropomum (Serrasalmidae). The influence of weight and temperature on the routine oxygen consumption
The influence of weight and temperature on the routine oxygen consumption of Colossoma macropomum, a Neotropical fish species of the family Serrasalmidae, was investigated using a constant flow respirometer. Plotted on a double logarithmic grid, oxygen consumption increases linearly with weight. Slopes of 0.64 at 25 and 30 °C, and 0.78 at 35 °C were obtained. Because of the significant difference in the slopes, a general value could not be provided. The metabolic rate of a 100 g fish increases from 103.7 to 191.5 and 289.7 mg O2/kg/h at 20, 25, and 30 °C, respectively. At 35 °C, the oxygen consumption rate decreased to 212.4 mg O2/kg/h. The metabolic rate is comparable to those of other tropical fish species. Obviously, Colossoma macropomum is well adapted to the constant temperature conditions of its Neotropical habitats
Kinetic Modelling for Tar Evolution and Formation in a Downdraft Gasifier
Biomass gasification modeling is a powerful tool
used to optimize the design of a gasifier. A detailed kinetic model
was built by the current authors [1] to predict the behavior of
air blown downdraft gasifier for a wide range of materials
within the range of (38≤C≤52) %, (5.2≤H≤7) %, and
(21.7≤O≤45) %. The model was verified and showed a good
stability for a wide range of working parameters like
equivalence ratio and moisture content. In the current research,
4 main tar species are added to the model to represent tar
formation using detailed kinetic reactions. The yield of tar
species is discussed for different zones of a gasifier based on
temperature of each zone. Mass and energy balance are
calculated. 18 different kinetic reactions are implemented in the
kinetic code to predict the optimum working conditions that
leads to the production of higher value producer gas. Results
conclude that using ER of 0.3 with moisture content levels lower
than 10% will lead to the production of higher yields of syngas
with lower amounts of tar
Accretion mode changes in Centaurus X-3
We report here discovery of the existence of two different accretion modes in
the high mass X-ray binary pulsar Cen X-3 during its high states. The multiband
X-ray light curves of Cen X-3 lasting for more than 3400 days obtained with the
All Sky Monitor (ASM) onboard the Rossi X-ray Timing Explorer (RXTE) shows many
episodes of high and low X-ray intensities. The high intensity phases last
between a few to upto 110 days and the separation between two high intensity
phases also varies widely. One remarkable feature deduced from the RXTE-ASM
light curves is that during these high intensity phases, Cen X-3 manifests in
two very distinct spectral states. When the source makes a transition from the
low intensity phase to the high intensity phase, it adopts one of these two
spectral states and during the entire high intensity phase remains in that
particular spectral state. During December 2000 to April 2004, all the high
intensity episodes showed a hardness ratio which is significantly larger than
the same during all the high states prior to and subsequent to this period. It
is also found that most of the soft outbursts reach a nearly constant peak flux
in the 5--12 keV band. For comparison, similar analysis was carried out on the
long term X-ray light curves of three other X-ray binary pulsars Her X-1, Vela
X-1, and SMC X-1. Results obtained with these sources are also presented here
and we found that none of the other sources show such a behaviour. From these
observations, we suggest that Cen X-3 has two different accretion modes and in
the course of nine years it has exhibited two switch overs between these.Comment: 5 pages, 5 postscript figures, accepted for publication in Astronomy
and Astrophysics Letter
Comment on: Reply to comment on `Perfect imaging without negative refraction'
Whether or not perfect imaging is obtained in the mirrored version of
Maxwell's fisheye lens is debated in the comment/reply sequence
[Blaikie-2010njp, Leonhardt-2010njp] discussing Leonhardt's original paper
[Leonhardt-2009njp]. Here we show that causal solutions can be obtained without
the need for an "active localized drain", contrary to the claims in
[Leonhardt-2010njp].Comment: v2 (added MEEP ctl file), v3 (publisher statement
Hard-Loop Dynamics of Non-Abelian Plasma Instabilities
Non-Abelian plasma instabilities may be responsible for the fast apparent
quark-gluon thermalization in relativistic heavy-ion collisions if their
exponential growth is not hindered by nonlinearities. We study the real-time
evolution of instabilities in an anisotropic non-Abelian plasma with an SU(2)
gauge group in the hard-loop approximation. We find exponential growth of
non-Abelian plasma instabilities both in the linear and in the strongly
nonlinear regime, with only a brief phase of subexponential behavior in
between.Comment: 4 pages REVTEX4, 3 figures; updated to match version published in
Phys. Rev. Lett. (shorter introduction, added details on quality of numerical
simulation
The Integer Valued SU(3) Casson Invariant for Brieskorn spheres
We develop techniques for computing the integer valued SU(3) Casson
invariant. Our method involves resolving the singularities in the flat moduli
space using a twisting perturbation and analyzing its effect on the topology of
the perturbed flat moduli space. These techniques, together with Bott-Morse
theory and the splitting principle for spectral flow, are applied to calculate
the invariant for all Brieskorn homology spheres.Comment: 50 pages, 3 figure
B2B Infrastructures in the Process of Drug Discovery and Healthcare
In this paper we describe a demonstration of an innovative B2B infrastructure which can be used to support collaborations in the pharmaceutical industry to achieve the drug discovery goal. Based on experience gained in a wide range of collaborative projects in the areas of grid technology, semantics and data management we show future work and new topics in B2B infrastructures which arise when considering the use of patient records in the process of drug discovery and in healthcare applications
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