Electric Field Integral Equations for Electromagnetic Scattering Problems With Electrically Small and Electrically Large Regions

Numerically stable electric field integral equations (EFIE) are presented for electromagnetic scattering problems that may include both electrically small geometrically complex and electrically large regions. A reduced integrand is achieved by implementing quasi-static assumptions in the electrically small regions, full-wave methods in the electrically large regions, and applying appropriate coupling relations between the regions. Use of the method provides computational efficiency as well as insight into the conditions under which the electromagnetic fields within electrically small regions of the problem can be assumed to be primarily capacitive or inductive in nature. The theoretical development of the method is highlighted in this communication and then applied to examples of electrically small, inductively-loaded, and capacitively-loaded monopole antennas. The accuracy of the results is verified with two independent methods.     

Therapists' experiences treating Asian American women with eating disorders.

How do psychologists treat eating disorders (EDs) and subclinical issues in Asian American women in a culturally competent manner? Disordered eating and body dissatisfaction are so common in women that most therapists work with the issues to some degree, and it is increasingly likely they will see women of color. Asian American women are at significant risk and yet little treatment literature exists. Twelve therapists with experience in ED treatment were interviewed about their work with Asian American women. Grounded theory and consensual qualitative analysis methods were used to analyze the data, resulting in two central domains of conceptualization within the cultural context and treatment approach. Therapists reported that their clients were mostly first- and second-generation Americans who experienced acculturation stress and cultural conflict, particularly with elders. Other results suggested therapists perceived a strong connection between clients' desires to be thin and successful, and clients' efforts to conform to traditional Asian cultural values and fit in with U.S. mainstream culture. Therapists emphasized the cultural contextualization of family dynamics, developmental processes (e.g., individuation), and intergenerational conflicts. They viewed EDs as providing clients with culturally congruent coping strategies to affectively disconnect and to express distress. Treatment themes centered on psychoeducation and the importance of including parents in the treatment of their adult daughters. Helping clients navigate autonomy within the family and cultural context, and challenging clients and parents on the cultural (both Asian and mainstream U.S.) pressures regarding achievement and beauty were particularly important. Implications for therapy are discussed. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Using information, motivational enhancement, and skills training to reduce the risk of HIV infection for low-income urban women: A second randomized clinical trial.

This randomized clinical trial evaluated an HIV-risk reduction (HIV-RR) intervention based on the information–motivation–behavioral skills model. At baseline, 102 women (M age?=?29 years; 88% African American) completed a survey regarding HIV-related knowledge, risk perceptions, behavioral intentions, and risk behavior. Participants were then assigned to either the HIV-RR intervention or a health-promotion control group. Postintervention and follow-up data indicated that women in the HIV-RR program enhanced their knowledge and strengthened their risk reduction intentions relative to controls. Moreover, HIV-RR women who expressed "imperfect" intentions also increased their condom use, talked more with partners about condom use and HIV testing, and were more likely to have refused unprotected sex. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A wideband radar for high-resolution mapping of near-surface internal layers in glacial ice

Snow accumulation rate is an important parameter in determining the mass balance of polar ice sheets. Accumulation rate is currently determined by analyzing ice cores and snow pits. Inadequate sampling of the spatial variations in the ice sheet accumulation has resulted in accumulation rate uncertainties as large as 24%. We designed and developed a 600-900-MHz airborne radar system for high-resolution mapping of the near-surface internal layers for estimating the accumulation rate of polar ice sheets. Our radar system can provide improved spatial and temporal coverage by mapping a continuous profile of the isochronous layers in the ice sheet. During the 2002 field season in Greenland, we successfully mapped the near-surface layers to a depth of 200 m in the dry-snow zone, 120 m in the percolation zone, and 20 m in the melt zone. We determined the water equivalent accumulation rate at the NASA-U/spl I.bar/1 site to be 34.9/spl plusmn/5.1 cm/year from 1964 to 1992. This is in close agreement with the ice-core derived accumulation rate of 34.6 cm/year for the same period.     

Fully coupled solution of the equations for incompressible recirculating flows using a penalty-function finite-difference formulation

This paper describes two new solution algorithms for steady recirculating flows that use a penalty formulation to eliminate the pressure from the finite difference form of the governing equations. One algorithm uses successive substitution to linearize the equations, while the other employs the Newton-Raphson linearization. In both cases, the equations are solved in a fully coupled manner using a sparse matrix form of LU decomposition. The D'Yakonov iteration is used to avoid unnecessary factorizations of the coefficient matrix, significantly improving the computational efficiency. The Newton-Raphson linearization leads to faster convergence, but the execution times of the two methods are comparable. The algorithms converge rapidly and are robust to changes in grid size and Reynolds number. In a number of laminar two-dimensional flows, the new methods proved to be two to ten times faster than some conventional iterative methods.List of symbols A coefficient matrix - A _e area of east control-volume face - a coefficient in the discretization equations - â coefficients in the modified momentum equations in the penalty formulation, Eqs. (13) - b constant term in the discretization equations - F symbolic form of nonlinear system of equations, F ₍₎=A –b=0 - H characteristic length - J Jacobian matrix - n iteration number - P dimensionless pressure - p pressure - Re Reynolds number - U dimensionless u velocity - u x-direction velocity - V dimensionless v velocity - v y-direction velocity - X, Y dimensionless coordinates, X=x/H, Y=y/H - x, y physical coordinates - x x-direction width of the control volume - normalized error in the unconverged solution, Eqs. (19) - dimensionless penalty parameter, Eq. (7) - dimensional penalty parameter, Eq. (10) - viscosity - density