8,574 research outputs found
Wilms Tumour with Intracardiac Extension.
Wilms tumour or nephroblastoma is the most common renal tumour of in children. It accounts for 6% of all pediatric tumours and is the second most frequent intrabdominal solid organ tumour in children. Inferior vena cava (IVC) involvement by Wilms tumour occurs in 4-10% of patients and right atrium thrombus extension in less than 1%. Using a multidisciplinary approach, overall survival is excellent in Wilms tumour. We are presenting this case because Wilms tumour with right atrial thrombus is relatively rare and continues to remain a challenge for treating physicians
Resonant Electro-Optic Frequency Comb
High speed optical telecommunication is enabled by wavelength division
multiplexing, whereby hundreds of individually stabilized lasers encode the
information within a single mode optical fiber. In the seek for larger
bandwidth the optical power sent into the fiber is limited by optical
non-linearities within the fiber and energy consumption of the light sources
starts to become a significant cost factor. Optical frequency combs have been
suggested to remedy this problem by generating multiple laser lines within a
monolithic device, their current stability and coherence lets them operate only
in small parameter ranges. Here we show that a broadband frequency comb
realized through the electro-optic effect within a high quality whispering
gallery mode resonator can operate at low microwave and optical powers.
Contrary to the usual third order Kerr non-linear optical frequency combs we
rely on the second order non-linear effect which is much more efficient. Our
result uses a fixed microwave signal which is mixed with an optical pump signal
to generate a coherent frequency comb with a precisely determined carrier
separation. The resonant enhancement enables us to operate with microwave
powers three order magnitude smaller than in commercially available devices. We
can expect the implementation into the next generation long distance
telecommunication which relies on coherent emission and detection schemes to
allow for operation with higher optical powers and at reduced cost
Seasonal variation in the proximate composition of rock oyster Saccostrea cucullata from Bombay coast
Changes in proximate composition of soft tissue of rock oyster Saccostrea cucullata inhabiting a polluted station at Bandra (stn. B) and a relatively clean area at Mudh Island (stn. M) were studied. An average protein content of 48.88 plus or minus 3.73 and 53.68 plus or minus 3.59% were recorded respectively for oysters from stns. M and B and the difference was significant. Mean carbohydrate content in oysters from stn. M amounted to 14.69 plus or minus 3.22 whereas at stn. B it was 8.70 plus or minus 1.61 and the difference was found highly significant. However, appreciable variation between stations was not observed in lipid and carbon content in oysters. Suitable periods for harvesting of these organisms are suggested
A Comprehensive Review of Modulation Techniques used in Long Term Evolution
3rd Generation Partnership Project (3GPP) has come up with a technology called Long Term Evolution (LTE) to attain a new high-speed radio access in the field of mobile communications. Design of wireless communication system has been an important and challenging problem due to the nature of wireless channel. There are number of factors involved in the performance of a LTE system. Orthogonal Frequency Division Multiple Access (OFDMA) and Single Carrier Frequency Division (SC-FDMA) are a dominant part of future mobile communication. This paper describes about LTE physical layer, OFDMA and SC-FDMA receiver and transmitter structures, draw attention on the factor that influences the performance and improvement of multiple access techniques. The substantial use of the adaptive modulation in LTE is the main highlight of the paper. The selection of modulation techniques on the basis of BER, Error probability and SNR are computed
Life-cycle of the Pea Crab, Pinnotheres vicajii Chhapgar, infesting the clam, Paphia malabarica
Various crab stages commencing with the invasive stage to adult stages of male and female
in the lile cycle of Pinnotheres vicajii infesting the edible clam, Paphia malabarica, occurring
in the Mandovi estuary of Goa have been described. Except the adult male and female the rest
of the stages have been described here for the first time in this species. Zoeae larvae liberated
from the eggs carried by ovigerous females are characterized by the presence of 3 spines on the
carapace. Comparison of these larvae with those of other species has been attempted. Planktonic
zoea larvae in the estuary occur almost throughout the year with 2 peak periods in MayJune
and December-January, coinciding with high salinity conditions of waters. Egg counts
of 12 ovigerous females of different sizes show a minimum of 611 and a maximum of 3800 with
an average of 1853 eggs. An attempt has been made to study the host-symbiont relationship.
No signflcant damage has been noticed on the soft parts of the host and there is no marked difference
in the meat weight - whole weight relationships of the infested and non-infested clams.
However, a slight decrease has been noticed in the averages of meat weights of infested clams
in the bigger whole weight groups
Mean frequency estimation of narrowband signals
Journal ArticleAbstract-This letter shows that the single frequency approximation for a narrowband lowpass signal embedded in white noise using the Pisarenko harmonic decomposition algorithm is approximately the power-weighted mean frequency of the signal. Experimental results indicate that this method is superior to a commonly used Fourier transform based mean frequency estimation method
Robust estimation of fetal heart rate variability using doppler ultrasound
Journal ArticleAbstract-This paper presents a new measure of heart rate variability (HRV) that can be estimated using Doppler ultrasound techniques and is robust to variations in the angle of incidence of the ultrasound beam and the measurement noise. This measure employs the multiple signal characterization (MUSIC) algorithm which is a high-resolution method for estimating the frequencies of sinusoidal signals embedded in white noise from short-duration measurements. We show that the product of the square-root of the estimated signal-to-noise ratio (SNR) and the mean-square error of the frequency estimates is independent of the noise level in the signal. Since varying angles of incidence effectively changes the input SNR, this measure of HRV is robust to the input noise as well as the angle of incidence. This paper includes the results of analyzing synthetic and real Doppler ultrasound data that demonstrates the usefulness of the new measure in HRV analysis
Prediction of pregnancy-induced hypertension using coherence analysis
Journal ArticleABSTRACT This paper presents a novel method to predict hypertensive disorders in pregnancy using coherence analysis. Previous studies suggest that there is inadequate secondary trophoblast invasion in hypertensive pregnancies implying that there are differences in the functional relationships between the maternal and fetal circulations. Magnitude squared coherence (MSC) is a function with values between 0 and 1 that indicates how well two waveforms correspond to each other in the frequency domain. The results presented in this paper using the MSC of maternal and fetal blood flow velocity waveforms indicate that in complicated hypertensive pregnancies its value is lower than in non-hypertensive controls. With additional validation, this method has the potential to provide an early test for hypertensive obstetric complications
Mean frequency estimation of narrowband signals and its application to doppler ultrasound blood velocity waveform estimation
Journal ArticleABSTRACT Many applications involving Doppler signals require the accurate estimation of the power-weighted mean frequency over short durations of the signal due to it's nonstationarity. This paper presents a novel algorithm for estimating mean frequencies using the eigenstructure of the covariance matrix of the Doppler data. Experimental results indicate that this method is superior to the competing non-parametric methods
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