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CASE Cody was always a short child with stature at the 5th percentile of a standard growth curve since he was a toddler. His weight was between the 10th and [...]

Spaced antenna (SA) radars retrieve wind-fields by tracking resolution volume sized bins of scatterers as they advect between two physically displaced antennas. To date, SA methods have been applied for profiling the ionosphere and precipitation free atmosphere. The primary technological difficulty in applying these methods to probe precipitation at microwave frequencies is the requirement for such a short antenna separation that a significant overlap in apertures is necessary. In this article, we synthesize overlapped apertures by segmenting active phased-arrays into subarrays that are multiplexed in time. Antenna pattern measurements are then employed to evaluate beamforming errors on a family of implementations. Based on measurements and Monte Carlo simulations, we find that highly overlapping apertures are most immune to beam squint errors. This is because element-level phase errors are retained on the synthesized SAs and differential beam squint errors are minimized. Finally, we demonstrate a novel method to measure relative phase center displacement between SAs that obviates the need for near-field antenna measurements. [ABSTRACT FROM AUTHOR]

We evaluated the efficacy of a depot preparation of growth hormone (GH) in a 15% gelatin solution (GH-gel) in the treatment of 15 growth hormone-deficient children. The studies were designed to see if prolonging absorption of GH to achieve lower more physiological concentrations of GH in plasma would decrease the frequency of injection, reduce the amount of GH needed for effective therapeutic response, and improve the response to long-term treatment. We found that after a single dose of GH-gel the plasma concentrations of GH were lower than those achieved after the standard aqueous preparation. The preparation was efficacious in promoting growth and our 1st study of 6 patients suggested that GH-gel given twice a week had a growth response equal to that of the three-times a week aqueous schedule. However both schedules resulted in the frequently observed decreased growth rate during the second treatment year. Our 2nd study, attempting to ameliorate this waning effect by using the GH-gel preparation twice a week in a weight-adjusted dose during the entire second year did not resolve the problem. Thus, GH in depot gel results in more physiological plasma concentrations of GH and may be beneficial in reducing the quantity of hormone needed and the injection frequency but it does not offer a solution to the waning response to the long-term administration of GH. [ABSTRACT FROM AUTHOR]

Spaced antenna baseline wind retrievals, in conjunction with traditional Doppler measurements, are a potential means of fine angular resolution weather radar wind vector retrieval. A spaced antenna implementation on an X-band active phased array architecture is investigated via Monte Carlo simulations of the backscattered electric fields at the antenna array. Several retrieval methods are exercised on the data produced by the simulator. Parameters of the X-band spaced-antenna design are then optimized. Benefiting from the parametric fitting procedure inherent in the time domain slope at zero lag and full correlation analysis, the study finds both of these algorithms to be more immune to thermal noise than the spectral retrieval algorithms investigated. With appropriately chosen baselines, these time domain algorithms are shown to perform adequately for 5-dB SNR and above. The study also shows that the Gaussian slope at zero lag (G-SZL) algorithm leads to more robust estimates over a wider range of beamwidths than the Gaussian full correlation analysis (G-FCA) algorithm. The predicted performance of the X-band array is compared to a similar spaced antenna implementation on the S-band National Weather Radar Testbed (NWRT). Since the X-band signal decorrelates more rapidly (relative to S band), the X-band array accumulates more independent samples, thereby obtaining lower retrieval uncertainty. However, the same rapid decorrelation also limits the maximum range of the X-band array, as the pulse rate must be sufficiently high to sample the cross-correlation function. It also limits the range of tolerable turbulence velocity within the resolution cell. [ABSTRACT FROM AUTHOR]

Total backscatter-coefficient inversion error bounds for the two-component lidar inversion algorithm (so-called Fernald's or Klett-Fernald-Sasano's method) are derived in analytical form in response to the following three error sources: 1) the measurement noise; 2) the user uncertainty in the backscatter-coefficient calibration; and 3) the aerosol extinction-to-backscatter ratio. The following two different types of error bounds are presented: 1) approximate error bounds using first-order error propagation and 2) exact error bounds using a total-increment method. Both error bounds are formulated in explicit analytical form, which is of advantage for practical physical sensitivity analysis and computational implementation. A Monte Carlo approach is used to validate the error bounds at 355-, 532-, and 1064-nm wavelengths. [ABSTRACT FROM AUTHOR]

A method is described for adjusting the far-field polarization of an electronically steered phased-array antenna. In this method, the polarization of a small subset of array elements is switched in order to reduce far-field cross-polarization of the overall array. The technique is intended for antennas used in polarimetric radars that measure quantities such as differential reflectivity (Zdr) and specific differential phase (KDP). In particular, it is appropriate for lower cost arrays where only one transmit or receive polarization is active at a time. In such arrays, it will reduce the number of measurements needed by one-third. Analysis of the tradeoffs in the technique is presented as well as examples in hypothetical large arrays. Measured results are presented for a small 4×4 array. [ABSTRACT FROM AUTHOR]

In this work, the accuracy of the Doppler beam-swinging (DBS) technique for wind measurements is studied using an imaging radar—the turbulent eddy profiler (TEP) developed by the University of Massachusetts, with data collected in summer 2003. With up to 64 independent receivers, and using coherent radar imaging (CRI), several hundred partially independent beams can be formed simultaneously within the volume defined by the transmit beam. By selecting a subset of these beams, an unprecedented number of DBS configurations with varying zenith angle, azimuth angle, and number of beams can be investigated. The angular distributions of echo power and radial velocity obtained by CRI provide a unique opportunity to validate the inherent assumption in the DBS method of homogeneity across the region defined by the beam directions. Through comparison with a reference wind field, calculated as the optimal uniform wind field derived from all CRI beams with sufficient signal-to-noise ratio (SNR), the accuracy of the wind estimates for various DBS configurations is statistically analyzed. It is shown that for a three-beam DBS configuration, although the validity of the homogeneity assumption is enhanced at smaller zenith angles, the root-mean-square (RMS) error increases because of the ill-conditioned matrix in the DBS algorithm. As expected, inhomogeneities in the wind field produce large bias for the three-beam DBS configuration for large zenith angles. An optimal zenith angle, in terms of RMS error, of approximately 9°–10° was estimated. It is further shown that RMS error can be significantly reduced by increasing the number of off-vertical beams used for the DBS processing. [ABSTRACT FROM AUTHOR]

The ability of high-resolution imaging systems to resolve small-scale structure on the ocean surface suggests the possibility of using characteristics of Langmuir circulation to map the surface mixed-layer depth and near-surface current. We illustrate this using synthetic aperture radar and infrared imagery that are collected across the edge of the Gulf Stream (GS), which reveals surfactant streaks, or ldquowindrows,rdquo that are induced by Langmuir circulation. Based on changes in the windrow spacing and orientation, the mixed layer is estimated to deepen from 7 to 12 m across the edge of the GS and the current to increase from about 1 to 2 m/s. These spatial changes compare reasonably well with independent data, suggesting that the approach is plausible. It may also be possible to extract additional environmental information from the windrows. [ABSTRACT FROM PUBLISHER]

The calibration of large antenna arrays in the absence of a beamforming point source is a common problem in beamforming radars and interferometric radiometers. In this paper the fundamentals of the redundant space calibration (RSC) method for phase and amplitude are reviewed, pointing out the parallelism between the active and passive cases, the technique is then applied in a general and systematic way to two cases of interest: hexagonal planar and Y-shaped arrays, which are known to be the optimum periodic two-dimensional configurations. In both cases, the system of equations is determined taking into account the available redundancies and symmetries of these structures. The performance of the RSC method is analysed in terms of the propagation of errors in reference phase/amplitude. The technique is then considered for two hexagonal array systems: the Turbulent Eddy Profiler (TEP), a volume-imaging radar of the lower atmosphere developed at the University of Massachusetts, and the Microwave Imaging Radiometer by Aperture Synthesis (MIRAS), an L-band interferometric radiometer to be launched in 2005 in the Earth Explorer Opportunity Mission--Soil Moisture and Ocean Salinity Mission (SMOS) of the European Space Agency (ESA). In the TEP case the proposed scheme stabilizes an otherwise ill-posed inversion problem, and in the MIRAS case it presents an alternative calibration method to the noise-injection one, without any additional hardware required. [ABSTRACT FROM AUTHOR]

Evaluates the experience which has been reported in the application of growth hormone stimulation tests to the laboratory confirmation of growth hormone deficiency in children. Confirmation of the original observation of low and frequently undetectable fasting plasma growth hormone levels in normal children; General agreement regarding the measurement of human growth hormone in a single fasting blood sample; Observation of a peak in the blood level of growth hormone in association with the onset of deep sleep.

Published data on the influence of hypothyroidism on fertility, gestation, and the offspring are controversial. We studied nine hypothyroid women during 11 pregnancies. Mean serum values for thyroxine, triiodothyronine (T3), resin T3 uptake ratio, and thyroid-stimulating hormone were 2.3 microgram/dL, 82 ng/dL, 0.64, and 105 mU/mL, respectively. Four patients had iatrogenic hypothyroidism (three remote thyroidectomy, one remote 131I therapy), two Hashimoto's thyroiditis, and three idiopathic primary hypothyroidism. Seven patients first presented untreated after the 24th week of gestation. Two patients needed cesarean section; seven delivered vaginally. There was one stillborn infant in the only patient with pre-eclampsia. Another infant had Down's syndrome and an ostium primum defect (mother's age, 41 years). The remaining nine infants were normal at birth. All placentas were normal. Follow-up in seven infants up to 2.7 years showed normal thyroid function and somatic development. Infants of hypothyroid mothers may be normal because their hypothalamic-pituitary thyroid axis develops independently from the mother. [ABSTRACT FROM AUTHOR]

The plasma concentration of androstenedione and testosterone, metabolic clearance rate of androstenedione, and in vivo conversion ratio of androstenedione to testosterone have been studied in a normotensive 5-year-old female with congenital adrenal hyperplasia due to a deficiency of 11 β-hydroxylase. Prior to glucocorticoid administration, the urinary excretion of 17-ketosteroids varied from 2.2 to 4.9 mg/24 hours, urinary excretion of pregnanetriol varied from 0.7 to 2.2 mg/24 hours, and total 17-hydroxysteroid excretion varied from 1.2 to 7.5 mg/24 hours. Urinary tetrahydro-11-deoxy cortisol (TSH) was detected at a concentration of 550 µg/24 hours. The plasma concentration of androstenedione varied from 100 to 530 mµg/100 ml and the plasma concentration of testosterone varied from 40 to 90 mµg/100 ml. These values are significantly elevated when compared to those obtained in normal prepubertal females. Urinary steroid excretion and plasma androgen concentrations fell to normal in response to glucocorticoid administration. The metabolic clearance rate of androstenedione was 890 liters per day per M² and the in vivo conversion ratio of androstenedione to testosterone was 11%. The calculated production rate of androstenedione was 4.7 mg per day per M². Virilization in congenital adrenal hyperplasia due to 11 β-hydroxylase deficiency can be explained by an elevated plasma concentration of testosterone, which can be accounted for on the basis of conversion from androstenedione. [ABSTRACT FROM AUTHOR]

Frasier syndrome is a relatively rare disorder associated with XY gonadal dysgenesis, gonadoblastoma, and kidney failure. In this report, we identify a classic mutation in the Wilms'' tumor 1 gene in one of the original cases of Frasier syndrome reported in this Journal in 1964. [Copyright &y& Elsevier]