1,071 research outputs found
On The Injection Spectrum of Ultrahigh Energy Cosmic Rays in the Top-Down Scenario
We analyze the uncertainties involved in obtaining the injection spectra of
UHECR particles in the top-down scenario of their origin. We show that the
DGLAP evolution of fragmentation functions (FF) to (mass of the X
particle) from their initial values at low is subject to considerable
uncertainties. We therefore argue that, for x\lsim 0.1 (the region of
interest for most large values of interest, being the
scaled energy variable), the FF obtained from DGLAP evolution is no more
reliable than that provided, for example, by a simple Gaussian form (in the
variable ) obtained under the Modified Leading Log Approximation
(MLLA). Additionally, we find that for x\gsim0.1, the evolution in of
the singlet FF, which determines the injection spectrum, is ``minimal'' -- the
singlet FF changes by barely a factor of 2 after evolving it over 14
orders of magnitude in . We, therefore, argue that as long as the
measurement of the UHECR spectrum above \sim10^{20}\ev is going to remain
uncertain by a factor of 2 or larger, it is good enough for most practical
purposes to directly use any one of the available initial parametrisations of
the FFs in the region x\gsim0.1 based on low energy data even without
evolving them to the requisite value.Comment: Minor changes, added a reference, version to appear in Phys. Rev.
Cellular landscaping of COVID-19 and gynaecological cancers: An infrequent correlation
COVID-19 resulted in a mortality rate of 3-6% caused by SARS-CoV-2 and its variant leading to unprecedented consequences of acute respiratory distress septic shock and multiorgan failure. In such a situation, evaluation, diagnosis, treatment, and care for cancer patients are difficult tasks faced by medical staff. Moreover, patients with gynaecological cancer appear to be more prone to severe infection and mortality from COVID-19 due to immunosuppression by chemotherapy and coexisting medical disorders. To deal with such a circumtances oncologists have been obliged to reconsider the entire diagnostic, treatment, and management approach. This review will provide and discuss the molecular link with gynaecological cancer under COVID-19 infection, providing a novel bilateral relationship between the two infections. Moreover, the authors have provided insights to discuss the pathobiology of COVID-19 in gynaecological cancer and their risks associated with such comorbidity. Furthermore, we have depicted the overall impact of host immunity along with guidelines for the treatment of patients with gynaecological cancer under COVID-19 infection. We have also discussed the feasible scope for the management of COVID-19 and gynaecological cancer
The Effect of P2P File Sharing on Music Markets: A SurvivalAnalysisofAlbums on Ranking Charts
Recent technological and market forces have profoundly impacted the
music industry. Emphasizing threats from peer-to-peer (P2P)
technologies, the industry continues to seek sanctions against
individuals who offer significant number of songs for others to copy.
Yet there is little rigorous empirical analysis of the impacts of online
sharing on the success of music products. Combining data on the
performance of music albums on the Billboard charts with file sharing
data from a popular network, we: 1) assess the impact of recent
developments related to the music industry on survival of music albums
on the charts, and 2) evaluate the specific impact of P2P sharing on an
album's survival on the charts. In the post P2P era, we find
significantly reduced chart survival. The second phase of our study
isolates the impact of file sharing on album survival. We find that
sharing does not seem to hurt the survival of albums
Turbulence and Multiscaling in the Randomly Forced Navier Stokes Equation
We present an extensive pseudospectral study of the randomly forced
Navier-Stokes equation (RFNSE) stirred by a stochastic force with zero mean and
a variance , where is the wavevector and the dimension . We present the first evidence for multiscaling of velocity structure
functions in this model for . We extract the multiscaling exponent
ratios by using extended self similarity (ESS), examine their
dependence on , and show that, if , they are in agreement with those
obtained for the deterministically forced Navier-Stokes equation (NSE). We
also show that well-defined vortex filaments, which appear clearly in studies
of the NSE, are absent in the RFNSE.Comment: 4 pages (revtex), 6 figures (postscript
The Effect of P2P File Sharing on Music Markets: A SurvivalAnalysisofAlbums on Ranking Charts
Recent technological and market forces have profoundly impacted the
music industry. Emphasizing threats from peer-to-peer (P2P)
technologies, the industry continues to seek sanctions against
individuals who offer significant number of songs for others to copy.
Yet there is little rigorous empirical analysis of the impacts of online
sharing on the success of music products. Combining data on the
performance of music albums on the Billboard charts with file sharing
data from a popular network, we: 1) assess the impact of recent
developments related to the music industry on survival of music albums
on the charts, and 2) evaluate the specific impact of P2P sharing on an
album's survival on the charts. In the post P2P era, we find
significantly reduced chart survival. The second phase of our study
isolates the impact of file sharing on album survival. We find that
sharing does not seem to hurt the survival of albums
Characterization of systematic error in Advanced LIGO calibration
The raw outputs of the detectors within the Advanced Laser Interferometer
Gravitational-Wave Observatory need to be calibrated in order to produce the
estimate of the dimensionless strain used for astrophysical analyses. The two
detectors have been upgraded since the second observing run and finished the
year-long third observing run. Understanding, accounting, and/or compensating
for the complex-valued response of each part of the upgraded detectors improves
the overall accuracy of the estimated detector response to gravitational waves.
We describe improved understanding and methods used to quantify the response of
each detector, with a dedicated effort to define all places where systematic
error plays a role. We use the detectors as they stand in the first half (six
months) of the third observing run to demonstrate how each identified
systematic error impacts the estimated strain and constrain the statistical
uncertainty therein. For this time period, we estimate the upper limit on
systematic error and associated uncertainty to be in magnitude and deg in phase ( confidence interval) in the most sensitive frequency
band 20-2000 Hz. The systematic error alone is estimated at levels of
in magnitude and deg in phase
Statistical Properties of Turbulence: An Overview
We present an introductory overview of several challenging problems in the
statistical characterisation of turbulence. We provide examples from fluid
turbulence in three and two dimensions, from the turbulent advection of passive
scalars, turbulence in the one-dimensional Burgers equation, and fluid
turbulence in the presence of polymer additives.Comment: 34 pages, 31 figure
Science with the Daksha High Energy Transients Mission
We present the science case for the proposed Daksha high energy transients
mission. Daksha will comprise of two satellites covering the entire sky from
1~keV to ~MeV. The primary objectives of the mission are to discover and
characterize electromagnetic counterparts to gravitational wave source; and to
study Gamma Ray Bursts (GRBs). Daksha is a versatile all-sky monitor that can
address a wide variety of science cases. With its broadband spectral response,
high sensitivity, and continuous all-sky coverage, it will discover fainter and
rarer sources than any other existing or proposed mission. Daksha can make key
strides in GRB research with polarization studies, prompt soft spectroscopy,
and fine time-resolved spectral studies. Daksha will provide continuous
monitoring of X-ray pulsars. It will detect magnetar outbursts and high energy
counterparts to Fast Radio Bursts. Using Earth occultation to measure source
fluxes, the two satellites together will obtain daily flux measurements of
bright hard X-ray sources including active galactic nuclei, X-ray binaries, and
slow transients like Novae. Correlation studies between the two satellites can
be used to probe primordial black holes through lensing. Daksha will have a set
of detectors continuously pointing towards the Sun, providing excellent hard
X-ray monitoring data. Closer to home, the high sensitivity and time resolution
of Daksha can be leveraged for the characterization of Terrestrial Gamma-ray
Flashes.Comment: 19 pages, 7 figures. Submitted to ApJ. More details about the mission
at https://www.dakshasat.in
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