2,095 research outputs found
Spectral Properties of M87 Using Two-Component Flow
We fit the observational data for M87 using two-component advective disk
model. We show that the flat spectrum from the nucleus of M87 is due to
synchrotron radiation produced by non-thermal electrons in the CENBOL. The
non-thermal distribution is produced due to acceleration of electrons across
the shock in a sub-Keplerian flow.Comment: 4 Pages, 1 Figures, Proceeding of the 2nd Kolkata Conference on
"Observational Evidence for the Black Holes in the Universe", Published in
AIP, 200
Consistent 3D Quantum Gravity on Lens Spaces
We study non-perturbative quantization of 3d gravity with positive
cosmological constant (de Sitter space being the prototype vacuum solution,
whose Euclideanization of course gives the three sphere) on the background
topology of lens space, which is a three spheres modulo a discrete group.
Instead of the strategy followed by a recent work \cite{Castro:2011xb}, which
compares results in the second and first order formulations of gravity, we
concentrate on the later solely. We note, as a striking feature, that the
quantization, that relies heavily on the axiomatics of topological quantum
field theory (TQFT) can only be consistently carried by augmenting the
conventional theory by an additional topological term coupled through a
dimensionless parameter. More importantly the introduction of this additional
parameter renders the theory finite.Comment: New section and references added. Accepted in Phys. Rev. D for
publicatio
Nonlocality without inequality for spin-s system
We analyze Hardy's non-locality argument for two spin-s systems and show that
earlier solution in this regard was restricted due to imposition of some
conditions which have no role in the argument of non-locality. We provide a
compact form of non-locality condition for two spin-s systems and extend it to
n number of spin-s particles. We also apply more general kind of non-locality
argument still without inequality, to higher spin system.Comment: 6 page
Nonlocality without inequality for almost all two-qubit entangled state based on Cabello's nonlocality argument
Here we deal with a nonlocality argument proposed by Cabello which is more
general than Hardy's nonlocality argument but still maximally entangled states
do not respond. However, for most of the other entangled states maximum
probability of success of this argument is more than that of the Hardy's
argument.Comment: 9 pages, 1 figur
SS 433: Results of a Recent Multi-wavelength Campaign
We conducted a multi-wavelength campaign in September-October, 2002, to
observe SS 433. We used 45 meter sized 30 dishes of Giant Meter Radio Telescope
(GMRT) for radio observation, 1.2 meter Physical Research Laboratory Infra-red
telescope at Mt Abu for IR, 1 meter Telescope at the State Observatory,
Nainital for Optical photometry, 2.3 meter optical telescope at the Vainu Bappu
observatory for spectrum and Rossi X-ray Timing Explorer (RXTE) Target of
Opportunity (TOO) observation for X-ray observations. We find sharp variations
in intensity in time-scales of a few minutes in X-rays, IR and radio
wavelengths. Differential photometry at the IR observation clearly indicated
significant intrinsic variations in short time scales of minutes throughout the
campaign. Combining results of these wavelengths, we find a signature of delay
of about two days between IR and Radio. The X-ray spectrum yielded double Fe
line profiles which corresponded to red and blue components of the relativistic
jet. We also present the broadband spectrum averaged over the campaign
duration.Comment: 17 pages 10 figures MNRAS (submitted
CSF Biomarkers for Alzheimer's Disease Diagnosis
Alzheimer's disease (AD) is the most common form of dementia that affects several million people worldwide. The major neuropathological hallmarks of AD are the presence of extracellular amyloid plaques that are composed of Aβ40 and Aβ42 and intracellular neurofibrillary tangles (NFT), which is composed of hyperphosphorylated protein Tau. While the amyloid plaques and NFT could define the disease progression involving neuronal loss and dysfunction, significant cognitive decline occurs before their appearance. Although significant advances in neuroimaging techniques provide the structure and physiology of brain of AD cases, the biomarker studies based on cerebrospinal fluid (CSF) and plasma represent the most direct and convenient means to study the disease progression. Biomarkers are useful in detecting the preclinical as well as symptomatic stages of AD. In this paper, we discuss the recent advancements of various biomarkers with particular emphasis on CSF biomarkers for monitoring the early development of AD before significant cognitive dysfunction
Technical and Economical Investigation of Renewable Energy Sources for Supplying Offshore Oil production Facilities at Gulf of Suez Area
The Gulf of Suez is highly susceptible to economic and energy security due to the heavy need for imported fossil fuels. The energy produced from fossil fuels causes serious environmental pollution. So, it is important to find other clean sources of energy for stabilizing the released amount of carbon dioxide. Gulf of Suez has the potential to develop clean Solar Photovoltaic (PV) and wind systems to improve economic and environmental performance. This paper proposes a combination of floating solar panels (FSP) and offshore wind turbines to solve the main critical issues, such as the land area required for a large number of cells and the space required for wind turbines. In addition to their good economical and environmental benefits. A simplified model is provided to investigate the replacement of traditional generating units (Diesel and Gas operated) supplying offshore oil production field facilities at the Gulf of Suez area with a mix of renewable resources. The load flow analysis is carried out for the model and the cost is calculated and compared for four schemas, the traditional generating, Wind-Gas, PV-Gas, and PV-Wind-Gas hybrid system. From the techno-economic analysis and comparing environmental benefits, floating solar systems and offshore wind turbines can provide a good solution to the existing problems of energy needs with environmental impacts considered
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