1,602 research outputs found

    Functional design for operational earth resources ground data processing

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    The author has identified the following significant results. Study emphasis was on developing a unified concept for the required ground system, capable of handling data from all viable acquisition platforms and sensor groupings envisaged as supporting operational earth survey programs. The platforms considered include both manned and unmanned spacecraft in near earth orbit, and continued use of low and high altitude aircraft. The sensor systems include both imaging and nonimaging devices, operated both passively and actively, from the ultraviolet to the microwave regions of the electromagnetic spectrum

    Interaction of surface acoustic waves with a two-dimensional electron gas in the presence of spin splitting of the Landau bands

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    The absorption and variation of the velocity of a surface acoustic wave of frequency ff= 30 MHz interacting with two-dimensional electrons are investigated in GaAs/AlGaAs heterostructures with an electron density n=(1.3−2.8)×1011cm−2n=(1.3 - 2.8) \times 10^{11} cm^{-2} at TT=1.5 - 4.2 K in magnetic fields up to 7 T. Characteristic features associated with spin splitting of the Landau level are observed. The effective g factor and the width of the spin-split Landau bands are determined: g∗≃5g^* \simeq 5 and AA=0.6 meV. The greater width of the orbital-split Landau bands (2 meV) relative to the spin-split bands is attributed to different shielding of the random fluctuation potential of charged impurities by 2D electrons. The mechanisms of the nonlinearities manifested in the dependence of the absorption and the velocity increment of the SAW on the SAW power in the presence of spin splitting of the Landau levels are investigated.Comment: Revtex 5 pages + 5 EPS Figures, v.2 - minor corrections in text and pic

    Physical Electronics

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    Contains reports on three research projects

    GOG 244-The lymphedema and gynecologic cancer (LEG) study: Incidence and risk factors in newly diagnosed patients

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    © 2019 Elsevier Inc. Objectives: To evaluate the incidence and risk factors for lymphedema associated with surgery for gynecologic malignancies on GOG study 244. Methods: Women undergoing a lymph node dissection for endometrial, cervical, or vulvar cancer were eligible for enrollment. Leg volume was calculated from measurements at 10-cm intervals starting 10 cm above the bottom of the heel to the inguinal crease. Measurements were obtained preoperatively and postoperatively at 4–6 weeks, and at 3-, 6-, 9-, 12-, 18-, and 24- months. Lymphedema was defined as a limb volume change (LVC) ≥10% from baseline and categorized as mild: 10–19% LVC; moderate: 20–40% LVC; or severe: \u3e40% LVC. Risk factors associated with lymphedema were also analyzed. Results: Of 1054 women enrolled on study, 140 were inevaluable due to inadequate measurements or eligibility criteria. This left 734 endometrial, 138 cervical, and 42 vulvar patients evaluable for LVC assessment. Median age was 61 years (range, 28–91) in the endometrial, 44 years (range, 25–83) in the cervical, and 58 years (range, 35–88) in the vulvar group. The incidence of LVC ≥10% was 34% (n = 247), 35% (n = 48), and 43% (n = 18), respectively. The peak incidence of lymphedema was at the 4–6 week assessment. Logistic regression analysis showed a decreased risk with advanced age (p = 0.0467). An exploratory analysis in the endometrial cohort showed an increased risk with a node count \u3e8 (p = 0.033). Conclusions: For a gynecologic cancer, LVC decreased with age greater than 65, but increased with a lymph node count greater than 8 in the endometrial cohort. There was no association with radiation or other risk factors
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