Large refractive index changes in tunable-electron-densityInGaAs/InAlAs quantum wells

Measurements of electrorefraction and electroabsorption in a multiple-quantum-well waveguide structure in which each InGaAs quantum well is provided with an individual electron reservoir are presented. External bias transfers electrons into the wells, thus quenching the absorption and producing a refractive index change at wavelengths below the bandedge which is linear in the applied voltage. It is shown that in this type of structure both the change in refractive index per applied field and the ratio of optical phase to intensity modulation can be significantly enhanced over those found in the quantum confined Stark effect     

Miniature Mach-Zehnder InGaAsP quantum well waveguideinterferometers for 1.3 μm

Electrooptic Mach-Zehnder interferometers with active lengths as small as 350 μm are discussed. These strip-loaded waveguide devices utilize the electrooptic effect in InGaAsP/InP quantum wells to achieve pi phase shift with single arm drive voltages of 12 V and 6 V drive in push-pull operation     

A Concise Parametric Representation of Electrocardiograms

This work is directed toward reducing the number of parameters necessary to describe the electrical activity of the heart. The approach taken is one of template matching using a linear combination of a set of template waveforms to fit a set of pattern waveforms. Using selected electrocardiogram (EKG) waveforms as a template results in a great reduction in the number of parameters needed to match other EKGs.     

Erythropoiesis in chronic renal disease

The diminished erythropoiesis in the anemia of chronic renal disease has been attributed to three possible factors: (1) decreased erythropoietin production, (2) inhibition of erythropoietin activity, and (3) decreased bone marrow response to erythropoietin. In this report we isolated and evaluated these parameters in 19 patients with chronic renal disease, nine patients with iron-deficiency anemia, and seven control subjects. The results in patients with chronic renal failure were as follows: (1) erythropoietin enhanced heme synthesis in bone marrow cell cultures by 88 +/- 12 per cent in renal failure, as compared to 65 +/- 7 per cent in the control group; (2) plasma erythropoietin activity did not increase appropriately for the degree of anemia; and (3) erythropoietin inhibitor activity in renal failure was not greater than in a control group. In conclusion, the relative failure of erythropoiesis in chronic renal disease appears to be due primarily to decreased production of erythropoietin and not to diminished marrow response to erythropoietin.     

Readout and control of a power-recycled interferometric gravitational-wave antenna

Interferometric gravitational-wave antennas are based on Michelson interferometers whose sensitivity to small differential length changes has been enhanced by the addition of multiple coupled optical resonators. The use of optical cavities is essential for reaching the required sensitivity but sets challenges for the control system, which must maintain the cavities near resonance. The goal for the strain sensitivity of the Laser Interferometer Gravitational-Wave Observatory (LIGO) is 10(-21) rms, integrated over a 100-Hz bandwidth centered at 150 Hz. We present the major design features of the LIGO length and frequency sensing and control system, which will hold the differential length to within 5 x 10(-14) m of the operating point. We also highlight the restrictions imposed by couplings of noise into the gravitational-wave readout signal and the required immunity against them.     

Early intervention in the path to alcohol problems through conduct problems: Treatment involvement and child behavior change.

A program for the prevention of conduct problems among preschool-age sons of alcoholic fathers was implemented to interrupt what is likely to be a major mediating factor in the development of alcoholism in later years. A population-based sample of 42 families participated in a 10-month intervention involving parent training and marital problem solving. Differences in treatment outcome were examined, with the expectation that level of treatment involvement—entailing both level of participation and level of investment—would account for variability in child outcome at termination. Significant changes in positive and negative child behaviors were observed only within the group of families who completed the program and where the mothers demonstrated a higher level of treatment investment. When pretreatment child, parent, and family predictors of child behavior change were accounted for, subsequent analyses identified maternal treatment investment as a significant predictor of child outcome. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

High-contrast electron-transfer GaAs-AlGaAs multiple-quantum-well waveguide modulator

The development of a GaAs-AlGaAs multiple quantum well electron transfer waveguide modulator is reported. On-off ratios as high as 75:1 are obtained at 864.5 nm of an applied voltage of -5 to 10 V. It is shown that the wavelength and voltage characteristics of the device can be successfully interpreted in terms of the calculated energy band diagram.<>     

Social support and stress factors in child maltreatment among alcoholic families.

Investigated the relationships among social support, stress, child maltreatment, and child aggressiveness in alcoholic families. Ss were 62 fathers, 65 mothers, and 65 children (aged 3–5 yrs). Three process models based on prior research were proposed and tested against one another using path analysis. Results suggest that for fathers, social support and stress were each independent direct predictors of child maltreatment. For mothers, social support was an indirect predictor of child maltreatment, and it buffered (moderated) the effect of stress on child maltreatment. For both fathers and mothers, lifetime alcohol problems predicted extent of child maltreatment. The data also indicate that child maltreatment influenced child aggressiveness. (French abstract) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Transformations of normal and inverted function tables

We develop a theory of function tables, similar to, and inspired by, that given in the work of D. Parnas. We consider, in particular, two classes of function tables: normal and inverted. We study effective transformations between tables of these two classes, as well as transformations which change the dimension of a table. We also consider the interrelationship between these three types of transformation.