Bladder carcinoma is one of the most common urological malignancies with many rare histological variants associated with various prognosis. The recognition of these rare histological variants of ...bladder carcinoma may be helpful in selecting appropriate therapeutic approach and to predict the prognosis of the patients. We present three such rare entities of urothelial carcinoma with squamous differentiation, squamous cell carcinoma of bladder and metastatic bladder carcinoma which are associated with bad prognosis.
Understanding the evolution of Universe is, in the forefront of, the modern day observational cosmology. It requires precise and accurate measurement of cosmological
signal, orders of magnitude ...weaker than the bright sky background. Detection of such a signal having distinct spectral signature, needs an antenna with frequency independent
characteristics over more than an octave bandwidth. A spherical monopole antenna has been designed to operate in the frequency range 50-200 MHz with a spectral smoothness of about few parts in 104. The structure has been modeled and optimized using WIPL-D, to minimize spectral features arising out of abrupt reflections of surface currents and frequency dependent radiation patterns. A prototype has been built to validate the design. This paper presents the methodology adopted in the overall antenna design, experiences in its prototyping and simulation and the measurement results.
Introduction: Among various methods of dental age (DA) estimation, Demirjian method and Nolla’s method are commonly used. One of the methods of determining cervical vertebral morphology was given by ...Hassel and Farman. Indian age-specific modified Demirjian method by Acharya has not been utilized in the Hyderabad population, and the age derivation information is sparse. Objectives: To correlate the DA using modified Demirjian’s method and Nolla’s method using orthopantomograph with skeletal maturation by cervical vertebral maturation index (CVMI) method using lateral cephalogram. They were compared and correlated for assessing chronological age (CA) and determining the accuracy. Materials and Methods: Among 200 boys and girls (100 each) between 6 and 21 years, the DA was evaluated using orthopantomogram by Ashith Acharya’s modified Demirjian method and also by Nolla’s method. The skeletal maturation was assessed by CVMI method given by Hassel and Farman using lateral cephalogram. These were compared and correlated with CA. The data derived were statistically analyzed using SPSS software 20.0 version. Results: The maximum underestimation of age was found within the age group of 19–19.9 years using Ashith Acharya’s modified Demirjian method and 18-18.9 years using Nolla’s method with median values of −5.05 and −5.03, respectively. Statistically significant difference was found between CAs and cervical vertebral maturation stages in both genders (P = 0.000). The study showed that girls had a late dental development compared to corresponding cervical maturation. Conclusions: The methods of age estimation were not reliable in predicting the accurate age in the Indian population.
The Murchison Wide-Field Array (MWA) is a low-frequency radio telescope, currently under construction, intended to search for the spectral signature of the epoch of reionization (EOR) and to probe ...the structure of the solar corona. Sited in western Australia, the full MWA will comprise 8192 dipoles grouped into 512 tiles and will be capable of imaging the sky south of 40° declination, from 80 MHz to 300 MHz with an instantaneous field of view that is tens of degrees wide and a resolution of a few arcminutes. A 32 station prototype of the MWA has been recently commissioned and a set of observations has been taken that exercise the whole acquisition and processing pipeline. We present Stokes
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integrations of a field 20° wide centered on Pictoris A. These images demonstrate the capacity and stability of a real-time calibration and imaging technique employing the weighted addition of warped snapshots to counter extreme wide-field imaging distortions.
We have carried out multiwavelength observations of the nearby (z = 0.046) rich, merging galaxy cluster Abell 3376 with the Murchison Widefield Array (MWA). As a part of the GaLactic and ...Extragalactic All-sky MWA Survey, this cluster was observed at 88, 118, 154, 188, and 215 MHz. The known radio relics, towards the eastern and western peripheries of the cluster, were detected at all the frequencies. The relics, with a linear extent of ∼1 Mpc each, are separated by ∼2 Mpc. Combining the current observations with those in the literature, we have obtained the spectra of these relics over the frequency range 80–1400 MHz. The spectra follow power laws, with α = −1.17 ± 0.06 and −1.37 ± 0.08 for the west and east relics, respectively (S∝να). Assuming the break frequency to be near the lower end of the spectrum we estimate the age of the relics to be ∼0.4 Gyr. No diffuse radio emission from the central regions of the cluster (halo) was detected. The upper limit on the radio power of any possible halo that might be present in the cluster is a factor of 35 lower than that expected from the radio power and X-ray luminosity correlation for cluster haloes. From this we conclude that the cluster halo is very extended (>500 kpc) and/or most of the radio emission from the halo has decayed. The current limit on the halo radio power is a factor of 10 lower than the existing upper limits with possible implications for models of halo formation.
Detection of the fluctuations in a 21cm line emission from neutral hydrogen during the Epoch of Reionization in thousand hour integrations poses stringent requirements on calibration and image ...quality, both of which necessitate accurate primary beam models. The Murchison Widefield Array (MWA) uses phased-array antenna elements which maximize collecting area at the cost of complexity. To quantify their performance, we have developed a novel beam measurement system using the 137MHz ORBCOMM satellite constellation and a reference dipole antenna. Using power ratio measurements, we measure the in situ beampattern of the MWA antenna tile relative to that of the reference antenna, canceling the variation of satellite flux or polarization with time. We employ angular averaging to mitigate multipath effects (ground scattering) and assess environmental systematics with a null experiment in which the MWA tile is replaced with a second-reference dipole. We achieve beam measurements over 30dB dynamic range in beam sensitivity over a large field of view (65% of the visible sky), far wider and deeper than drift scans through astronomical sources allow. We verify an analytic model of the MWA tile at this frequency within a few percent statistical scatter within the full width at half maximum. Toward the edges of the main lobe and in the sidelobes, we measure tens of percent systematic deviations. We compare these errors with those expected from known beamforming errors. Key Points We develop an antenna beam measurement system using the ORBCOMM constellation We make precision MWA antenna tile beam measurements at Green Bank, WV We measure MWA beams down to 30dB from boresight over 65% of the visible sky
Low‐frequency, wide field‐of‐view (FOV) radio telescopes such as the Murchison Widefield Array (MWA) enable the ionosphere to be sampled at high spatial completeness. We present the results of the ...first power spectrum analysis of ionospheric fluctuations in MWA data, where we examined the position offsets of radio sources appearing in two data sets. The refractive shifts in the positions of celestial sources are proportional to spatial gradients in the electron column density transverse to the line of sight. These can be used to probe plasma structures and waves in the ionosphere. The regional (10–100 km) scales probed by the MWA, determined by the size of its FOV and the spatial density of radio sources (typically thousands in a single FOV), complement the global (100–1000 km) scales of GPS studies and local (0.01–1 km) scales of radar scattering measurements. Our data exhibit a range of complex structures and waves. Some fluctuations have the characteristics of traveling ionospheric disturbances, while others take the form of narrow, slowly drifting bands aligned along the Earth's magnetic field.
Key Points
First spatiotemporal power spectrum analysis of ionospheric structures by MWA
High sampling completeness and large FOV of MWA allow it to image ionosphere
Detect plane wavelike structures, including TIDs and field‐aligned ducts
Refraction and diffraction of incoming radio waves by the ionosphere induce time variability in the angular positions, peak amplitudes and shapes of radio sources, potentially complicating the ...automated cross-matching and identification of transient and variable radio sources. In this work, we empirically assess the effects of the ionosphere on data taken by the Murchison Widefield Array (MWA) radio telescope. We directly examine 51 h of data observed over 10 nights under quiet geomagnetic conditions (global storm index K
p < 2), analysing the behaviour of short-time-scale angular position and peak flux density variations of around ten thousand unresolved sources. We find that while much of the variation in angular position can be attributed to ionospheric refraction, the characteristic displacements (10–20 arcsec) at 154 MHz are small enough that search radii of 1–2 arcmin should be sufficient for cross-matching under typical conditions. By examining bulk trends in amplitude variability, we place upper limits on the modulation index associated with ionospheric scintillation of 1–3 per cent for the various nights. For sources fainter than ∼1 Jy, this variation is below the image noise at typical MWA sensitivities. Our results demonstrate that the ionosphere is not a significant impediment to the goals of time-domain science with the MWA at 154 MHz.
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