Airborne lidar observations of Arctic polar stratospheric clouds

Polar stratospheric clouds (PSC's) have been detected repeatedly during Arctic and Antarctic winters since 1978/1979 by the SAM II (Stratospheric Aerosol Measurement II) instrument aboard the NIMBUS-7 satellite. PSC's are believed to form when supercooled sulfuric acid droplets freeze, and subsequently grow by deposition of ambient water vapor as the local stratospheric temperature falls below the frost point. In order to study the characteristics of PSC's at higher spatial and temporal resolution than that possible from the satellite observations, aircraft missions were conducted within the Arctic polar night vortex in Jan. 1984 and Jan. 1986 using the NASA Langley Research Center airborne dual polarization ruby lidar system. A synopsis of the 1984 and 1986 PSC observations is presented illustrating short range spatial changes in cloud structure, the variation of backscatter ratio with temperature, and the depolarization characterics of cloud layers. Implications are noted with regard to PSC particle characteristics and the physical process by which the clouds are thougth to form

Panel discussion

"The Importance of Being Predictable" by John B. Taylor -- "Monetary Policy Under Uncertainty" by Ben S. Bernanke -- "The Importance of Being Predictable" by William PooleMonetary policy

Few-electron quantum dots in III-V ternary alloys: role of fluctuations

We study experimentally the electron transport properties of gated quantum dots formed in InGaAs/InP and InAsP/InP quantum well structures grown by chemical-beam epitaxy. For the case of the InGaAs quantum well, quantum dots form directly underneath narrow gate electrodes due to potential fluctuations. We measure the Coulomb-blockade diamonds in the few-electron regime of a single quantum dot and observe photon-assisted tunneling peaks under microwave irradiation. A singlet-triplet transition at high magnetic field and Coulomb-blockade effects in the quantum Hall regime are also observed. For the InAsP quantum well, an incidental triple quantum dot forms also due to potential fluctuations within a single dot layout. Tunable quadruple points are observed via transport measurements.Comment: 3.3 pages, 3 figures. Added two new subfigures, new references, and improved the tex

Panel discussion monetary policy modeling: where are we and where should we be going?

Monetary policy ; Inflation (Finance) ; Econometric models

Reducing Polarization Mode Dispersion With Controlled Polarization Rotations

One of the fundamental limitations to high bit rate, long distance, telecommunication in optical fibers is Polarization Mode Dispersion (PMD). Here we introduce a conceptually new method to reduce PMD in optical fibers by carrying out controlled rotations of polarization at predetermined locations along the fiber. The distance between these controlled polarization rotations must be less than both the beat length and the mode coupling length of the fiber. This method can also be combined with the method in which the fiber is spun while it drawn. The incidence of imperfections on the efficiency of the method is analysed.Comment: 4 page

HOW PROFESSIONAL PROVIDERS ADDRESS THE SELF-ESTEEM OF AFRICAN AMERICAN ADOLESCENT GIRLS LIVING IN LOW-INCOME COMMUNITIES

HOW PROFESSIONAL PROVIDERS ADDRESS THE SELF-ESTEEM OF AFRICAN AMERICAN ADOLESCENT GIRLS LIVING IN LOW-INCOME COMMUNITIES Khidhra Smith Poole MSW, LCSW Dr. Joretha Bourjolly MSW, PhD., Dissertation Chair Objective: This study aimed to explore how professionals are addressing the self-esteem of African American girls living in low-income communities. Factors such as gender, race, and socioeconomic status play a significant role in the development of a healthy self-esteem. Given the disproportionately high representation of African American youth among individuals living in poverty, their increased exposure to stress in the context of poverty, and the association between stress and psychological symptoms for African American girls, the search for protective factors that foster resilience for low-income African American girls is particularly important. Methods: A modified grounded theory approach was used to analyze audiotaped transcribed focus group discussions, self-esteem written intervention materials, and direct observation notes from self-esteem interventions conducted by study participants. Fennell’s cognitive model of low self-esteem was used as a theoretical framework for this study to help understand which factors contribute to low self-esteem and as a result need to be considered when improving overall self-esteem among African American adolescent girls living in low-income communities. Results: Teaching skills and providing opportunities for girls to practice new skills, guided group discussions and talks, exposure to new experiences, addressing basic needs, healthy relationship building, the positive use of self, spiritual/cultural approaches and the lack of family involvement were all themes that emerged when professionals addressed the self-esteem of African American adolescent girls living in low-income communities. The study also discovered that professionals should find ways to include the primary caregiver when addressing self-esteem with this group. Conclusions: The findings suggest that addressing self-esteem with this group begins with understanding their culture, listening to what they need and observing obstacles faced by these girls to sustain a healthy self-esteem. Implications for social work practice are discussed. Keywords: African American girls, African American youth, Self-Esteem