Amphibole content of cosmetic and pharmaceutical talcs.

Pharmaceutical and cosmetic-grade talcs were examined for asbestiform amphibole content using a new density-optical method. Talcs under the Food and Drug Administration are not regulated as to asbestos content; however, all talcs were well below the level mandated by the Occupational Safety and Health Administration for industrial talcs. Only one was found to contain an amphibole particle size distribution typical of asbestos

Rafiki: Children of Hope

Rafiki: Children or Hope .. is a story of\u27 survival, loss, hope and triumph. The explanatory narrative supplements the fifteen-minute documentary. and walks you through my journey of completing the video production. The video documentary exposes the reality the affect HIV/AIDS continues to have on Sub-Saharan Africa; more specifically, children at a small orphanage in Kikuyu, Kenya. Twenty-three children reside at Rafiki orphanage and each o[ those young faces all lost their parents to AlDS. Interviews with the House Mother and God Mother of Rafiki provide the organization history. Footage of the children reveals the emotional obstacles many of them were working to overcome. Rafiki is a Swahili word meaning friends or friendship\u27\u27 and this project was a collaborative effort between three friends. Tim Croskey, an engineer and videographer shot all of the video footage. His wife and Kenya native, Wangari Croskey, wrote the story behind the footage and I produced and edited the final project. Together, we created a powerful story showing that not all of\u27 Africa\u27s children are lost. This project proved to be challenging but. extremely rewarding. I spent a great deal logging various tapes of footage spanning the years of 2002 - 2006. Lack of communication with Tim and Wangari delayed crucial elements of the project. But I eventually obtained the English translations from Wangari and was able to move forward with recording audio. My passion for music and its power in documentaries guaranteed my selections would be chosen with care. I needed the film to emit a hopeful but melancholy mood. I wanted the viewer to feel the pain buried inside the children but also see the hope most of them finally bad. The project impressed upon me that you never stop learning. After all the elements of my project finally came together, the editing process proved to be the most difficult. Piecing together the recorded voiceovers with the taped interviews. creating original Li ties, correcting colors of shots, and deciding the proper format for the story - alI tested my assumed pre-existing knowledge. The AIDS epidemic spreading throughout Africa seems to be a losing battle. Nevertheless, the orphans at Rafiki are fighting and succeeding. Loise. the only orphan interviewed in the documentary is currently in college and studying Mass Communications. Although she lost both of her parents, she still has her will to fight the affects of such a deadly disease. From the solemn to the happy faces. I can only hope someone is touched and moved to support the Rafiki AIDS ministries after viewing my documentary

The Growth and Development of English Law

A study of the history of the development of English law

A Comparison of Pregnant/Parenting and Non-Pregnant/Non-Parenting Female Adolescents on Locus of Control and Perceived Parental Attachment

This study compared pregnant/parenting adolescent females and their childless counterparts on the variables of locus of control and perceived parental attachment. The sample was drawn from two high schools in the suburban St.. Louis area. Subjects completed the Levenson\u27s Multidimensional Locus of Control Subscales and the Parental Attachment Questionnaire. It was hypothesized that the pregnant/parenting group would score higher on the Powerful Others subscale of the Multidimensional Locus of Control instrument. Also, it was hypothesized that the pregnant/parenting group would score lower than the non-pregnant/non-parenting group on all of the subscales on the Parental Attachment Questionnaire for both mother and father. T-tests were conducted to analyze the relationships between the two groups. No significant differences were found between the two groups on any subscale

Optical injection and terahertz detection of the macroscopic Berry curvature

We propose an experimental scheme to probe the Berry curvature of solids. Our method is sensitive to arbitrary regions of the Brillouin zone, and employs only basic optical and terahertz techniques to yield a background free signal. Using semiconductor quantum wells as a prototypical system, we discuss how to inject Berry curvature macroscopically, and probe it in a way that provides information about the underlying microscopic Berry curvature.Comment: 4 pages, accepted in Physical Review Letter

Response of a particle in a one-dimensional lattice to an applied force: Dynamics of the effective mass

We study the behaviour of the expectation value of the acceleration of a particle in a one-dimensional periodic potential when an external homogeneous force is suddenly applied. The theory is formulated in terms of modified Bloch states that include the interband mixing induced by the force. This approach allows us to understand the behaviour of the wavepacket, which responds with a mass that is initially the bare mass, and subsequently oscillates around the value predicted by the effective mass. If Zener tunneling can be neglected, the expression obtained for the acceleration of the particle is valid over timescales of the order of a Bloch oscillation, which are of interest for experiments with cold atoms in optical lattices. We discuss how these oscillations can be tuned in an optical lattice for experimental detection.Comment: 15 pages, 12 figure

Anatomy of the quantum melting of the two dimensional Wigner crystal

The Fermi liquid-Wigner crystal transition in a two dimensional electronic system is revisited with a focus on the nature of the fixed node approximation done in quantum Monte Carlo calculations. Recently, we proposed (Phys. Rev. Lett. 94, 046801 (2005)) that for intermediate densities, a hybrid phase (with the symmetry of the crystal but otherwise liquid like properties) is more stable than both the liquid and the crystal phase. Here we confirm this result both in the thermodynamic and continuum limit. The liquid-hybrid transition takes place at rs=31.5 +/- 0.5. We find that the stability of the hybrid phase with respect to the crystal one is tightly linked to its delocalized nature. We discuss the implications of our results for various transition scenarii (quantum hexatic phase, supersolid, multiple exchange, microemulsions) proposed in the literature.Comment: 14 pages, 16 figure

Electron energy spectrum and the Berry phase in graphite bilayer

We emphasize that there exist four Dirac-type points in the electron-energy spectrum of a graphite bilayer near the point K of its Brillouin zone. One of the Dirac points is at the point K, and three Dirac points lie nearby. Each of these three points generates the Berry phase $\pi$, while the Dirac point at K gives the phase $-\pi$. It is these four points that determine the Berry phase in the bilayer. If an electron orbit surrounds all these points, the Berry phase is equal to $2\pi$.Comment: 4 pages, 2 figures, submitted to Phys. Rev. B ; expande