3,436 research outputs found
Observational constraints on dark matter-dark energy scattering cross section
In this letter, we report precise and robust observational constraints on
dark matter-dark energy scattering cross section, using the latest data from
cosmic microwave background (CMB) Planck temperature and polarization, baryon
acoustic oscillations (BAO) measurements and weak gravitational lensing data
from Canada-France-Hawaii Telescope Lensing Survey (CFHTLenS). The scattering
scenario consists of a pure momentum exchange between the dark components, and
we find at 95\% CL from the joint analysis
(CMB + BAO + CFHTLenS), for typical dark matter particle mass of the order 1-10
. We notice that the scattering among the dark components may
influence the growth of large scale structure in the Universe, leaving the
background cosmology unaltered.Comment: 6 pages, 4 figures, 1 table, Minor changes/additions, Matches the
version published in EPJ
Dark sector interaction: a remedy of the tensions between CMB and LSS data
The well-known tensions on the cosmological parameters and
within the CDM cosmology shown by the Planck-CMB and LSS data are
possibly due to the systematics in the data or our ignorance of some new
physics beyond the CDM model. In this letter, we focus on the second
possibility, and investigate a minimal extension of the CDM model by
allowing a coupling between its dark sector components (dark energy and dark
matter). We analyze this scenario with Planck-CMB, KiDS and HST data, and find
that the and tensions disappear at 68\% CL. In the joint
analyzes with Planck, HST and KiDS data, we find non-zero coupling in the dark
sector up to 99\% CL. Thus, we find a strong statistical support from the
observational data for an interaction in the dark sector of the Universe while
solving the and tensions simultaneously.Comment: 5 pages, 3 figure
Computational binding mechanism of Mycobacterium tuberculosis UDP-NAG enolpyruvyl transferase (MurA) with inhibitors fosfomycin, cyclic disulfide analog RWJ-3981, pyrazolopyrimidine analog RWJ-110192, purine analog RWJ-140998, 5-sulfonoxy-anthranilic aci
Worldwide, tuberculosis (TB) remains the most frequent and important infectious disease causing morbidity and death. One-third of the world's population is infected with Mycobacterium tuberculosis (Mtb), the etiologic agent of TB. In this context, TB is in the top three, with malaria and HIV being the leading causes of death from a single infectious agent, and about two million deaths are attributable to TB annually. The bacterial enzyme MurA catalyzes the transfer of enolpyruvate from phosphoenolpyruvate (PEP) to uridine diphospho-N-acetylglucosamine (UNAG), which is the first committed step of bacterial cell wall biosynthesis. In this work, 3D structural model of Mtb-MurA enzyme has been developed, for the first time, by homology modeling and molecular dynamics simulation techniques. The model provided clear insight in its structure features, i.e. substrate binding pocket, and common docking site. Multiple sequence alignment and 3D structure model provided the putative substrate binding pocket of Mtb-MurA with respect to E.coli MurA. This analysis was helpful in identifying the binding sites and molecular function of the MurA homologue. Molecular docking study was performed on this 3D structural model, using different classes of inhibitors like fosfomycin, cyclic disulfide analog RWJ-3981, pyrazolopyrimidine analog RWJ-110192, purine analog RWJ-140998, 5-sulfonoxy-anthranilic acid derivatives T6361, T6362 and the results showed that the 5-sulfonoxyanthranilic acid derivatives is showed best interaction compared with other inhibitor, taking in to this we also design a new efficient analogs of T6361 and T6362 which are showed even better interaction with Mtb-MurA than the parental5-sulfonoxy-anthranilic acid derivatives. Further the comparative molecular electrostatic potential and cavity depth analysis of Mtb-MurA suggested several important differences in its substrate and inhibitor binding pocket. Such differences could be exploited in the future for designing of a more specific inhibitor for Mtb-MurA enzym
Synthesis and Antimicrobial Activity of 2-(Aminoacid ester)-3-(6-methyl-2-pyridyl)-3,4-dihydro-2H-1,3,2 λ5- benzoxazaphosphinin-2-thiones
Synthesis of 2-(aminoacid ester)-3-(6-methyl-2-pyridyl)-3,4-dihydro-2H-1,3,2λ5-benzoxazaphosphinin-2-thiones (3a–j) was accomplished through a two-step process. It involves the prior preparation of 2-chloro-3-(6-methyl-2-pyridyl)-3,4-dihydro-2H-1,3,2λ5-benzoxazaphosphinin-2-thione monochloride (2) and its subsequent reaction with the aminoacid ester hydrochlorides in dry tetrahydrofuran-toluene in the presence of triethylamine at various temperatures. These compounds were characterizedby IR, 1H, 13C, 31P NMR and mass spectral data.Keywords: 2-[(6-methyl-2-pyridyl) amino] methylphenol, 1,3,2-benzoxazaphosphinin-2-thione, antimicrobial activit
Updating non-standard neutrinos properties with Planck-CMB data and full-shape analysis of BOSS and eBOSS galaxies
Using the latest observational data from Planck-CMB and its combination with
the pre-reconstructed full-shape (FS) galaxy power spectrum measurements from
the BOSS DR12 sample and eBOSS LRG DR16 sample, we report the observational
constraints on the cosmic neutrino properties given by the extended
CDM scenario: CDM + + +
+ + , and its particular case
CDM + + + , where , , , , are the
effective number of species, the total neutrino mass, the sound speed in the
neutrinos rest frame, the viscosity parameter and the degeneracy parameter
quantifying a cosmological leptonic asymmetry, respectively. We observe that
the combination of FS power spectrum measurements with the CMB data
significantly improves the parametric space of the models compared to the CMB
data alone case. We find no evidence for neutrinos properties other than the
ones predicted by the standard cosmological theory. Our most robust
observational constraints are given by CMB + BOSS analysis. For the generalized
extended CDM scenario, we find , ,
, at 68\% CL, with eV at 95\% CL. These are the strongest limits ever reported for these
extended CDM scenarios.Comment: 22 pages, 4 figures, 3 tables; Substantial changes in the text with
updated results; matches the version published in JCAP except some additional
refs in this versio
Passive Source Localization Using Compressively Sensed Towed Array
The objective of this work is to estimate the sparse angular power spectrum using a towed acoustic pressure sensor (APS) array. In a passive towed array sonar, any reduction in the analog sensor signal conditioning receiver hardware housed inside the array tube, significantly improves the signal integrity and hence the localization performance. In this paper, a novel sparse acoustic pressure sensor (SAPS) array architecture is proposed to estimate the direction of arrival (DOA) of multiple acoustic sources. Bearing localization is effectively achieved by customizing the Capons spatial filter algorithm to suit the SAPS array architecture. Apart from the Monte Carlo simulations, the acoustic performance of the SAPS array with compressively sensed minimum variance distortionless response (CS-MVDR) filter is demonstrated using a real passive towed array data. The proposed sparse towed array architecture promises a significant reduction in the analog signal acquisition receiver hardware, transmission data rate, number of snapshots and software complexity.Defence Science Journal, 2013, 63(6), pp.630-635, DOI:http://dx.doi.org/10.14429/dsj.63.576
New cosmological constraints on gravity in the light of full Planck-CMB and type Ia Supernovae data
We investigate two new observational perspectives in the context of torsional
gravitational modification of general relativity, i.e., the gravity: i)
We use Pantheon data of type Ia supernovae motivated by a time variation of the
Newton's constant on the supernovae distance modulus relation, and find that a
joint analysis with Baryon Acoustic Oscillations (BAO) and Big Bang
Nucleosynthesis (BBN), i.e., Pantheon+BAO+BBN, provides constraints on the
effective free parameter of the theory to be well compatible with the
CDM prediction; ii) We present the framework of gravity at the
level of linear perturbations with the phenomenological functions, namely the
effective gravitational coupling and the light deflection parameter
, which are commonly used to parameterize possible modifications of the
Poisson equation relating the matter density contrast to the lensing and the
Newtonian potentials, respectively. We use the available Cosmic Microwave
Background (CMB) data sets from the Planck 2018 release to constrain the free
parameters of the gravity and CDM models. We find that CMB
data, and its joint analyses with Pantheon and BAO data constrain the
gravity scenario to be practically indistinguishable from the CDM
model. We obtain the strongest limits ever reported on gravity scenario
at the cosmological level.Comment: 18 pages, 2 tables, 5 figure
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