Raman scattering of atoms from a quasi-condensate in a perturbative regime

It is demonstrated that measurements of positions of atoms scattered from a quasi-condensate in a Raman process provide information on the temperature of the parent cloud. In particular, the widths of the density and second order correlation functions are sensitive to the phase fluctuations induced by non-zero temperature of the quasi-condensate. It is also shown how these widths evolve during expansion of the cloud of scattered atoms. These results are useful for planning future Raman scattering experiments and indicate the degree of spatial resolution of atom-position measurements necessary to detect the temperature dependence of the quasi-condensate.Comment: 8 pages, 8 figure

Tradeoffs for number-squeezing in collisions of Bose-Einstein condensates

We investigate the factors that influence the usefulness of supersonic collisions of Bose-Einstein condensates as a potential source of entangled atomic pairs by analyzing the reduction of the number difference fluctuations between regions of opposite momenta. We show that non-monochromaticity of the mother clouds is typically the leading limitation on number squeezing, and that the squeezing becomes less robust to this effect as the density of pairs grows. We develop a simple model that explains the relationship between density correlations and the number squeezing, allows one to estimate the squeezing from properties of the correlation peaks, and shows how the multi-mode nature of the scattering must be taken into account to understand the behavior of the pairing. We analyze the impact of the Bose enhancement on the number squeezing, by introducing a simplified low-gain model. We conclude that as far as squeezing is concerned the preferable configuration occurs when atoms are scattered not uniformly but rather into two well separated regions.Comment: 13 pages, 13 figures, final versio

Knowledge of dengue among students in Universiti Sultan Zainal Abidin (UNISZA), Terengganu, Malaysia and the influence of knowledge of dengue on attitude and practice

Reducing the vector population not only organization responsible, individual itself plays as important role in dengue prevention and control. Upon the understanding of the value of baseline data, a cross-sectional study was carried out in the dengue hotspot areas in Universiti Sultan Zainal Abidin (UniSZA). The study results show that 83.9% of the population had a high level of knowledge, 10.6% had a good attitude and 81.8% were performing good practice against dengue infection. After adjusting confounding variables, age and educational level of respondents, knowledge as well as attitude were found to be significant associated factors for having good practice against dengue. The study findings provide the need for further information to undertake a holistic approach, which is in need of community participation and cooperation.Keywords: dengue fever; knowledge; attitudes; practice; studen

Quasilocal energy for rotating charged black hole solutions in general relativity and string theory

We explore the (non)-universality of Martinez's conjecture, originally proposed for Kerr black holes, within and beyond general relativity. The conjecture states that the Brown-York quasilocal energy at the outer horizon of such a black hole reduces to twice its irreducible mass, or equivalently, to \sqrt{A} /(2\sqrt{pi}), where `A' is its area. We first consider the charged Kerr black hole. For such a spacetime, we calculate the quasilocal energy within a two-surface of constant Boyer-Lindquist radius embedded in a constant stationary-time slice. Keeping with Martinez's conjecture, at the outer horizon this energy equals the irreducible mass. The energy is positive and monotonically decreases to the ADM mass as the boundary-surface radius diverges. Next we perform an analogous calculation for the quasilocal energy for the Kerr-Sen spacetime, which corresponds to four-dimensional rotating charged black hole solutions in heterotic string theory. The behavior of this energy as a function of the boundary-surface radius is similar to the charged Kerr case. However, we show that in this case it does not approach the expression conjectured by Martinez at the horizon.Comment: 15 page

Glycerol residue - a rich source of glycerol and medium chain fatty acids

Glycerol residue, a by-product of glycerol refining from a palm kernel oil methyl ester plant, was found to be a good source of glycerol and medium chain fatty acids. From analyses of twelve samples, it was found to contain, on average, 20.2 % glycerol and 6.6 % fatty acids. The fatty acids comprised mainly C8:0 (30.3 %), C10:0 (9.4 %) and C12:0 (40.8 %)

Improving jitney service quality : an appropriate governance model for San Juan, Puerto Rico

Thesis (M.C.P.)--Massachusetts Institute of Technology, Dept. of Urban Studies and Planning, 2002.Includes bibliographical references (p. 154-160).San Juan, Puerto Rico, like many North American cities, has turned to rail lines as a solution to the mounting traffic congestion threatening the urban environment. However, a rail system must rely on other transit modes to provide feeder services in order to expand its reach and broaden its customer base. This requires intermodal integration. The challenge facing the future success of Tren Urbano, the new rail system projected to open in the next two years, is the integration of the publicos. The publico is the owner operated jitney service indigenous to Puerto Rico that the government anticipates will offer crucial feeder services to Tren Urbano. For intermodal integration to succeed, publicos must offer comparable service quality. Unfortunately, the service quality of publico transit is poor as a consequence of the long-term decline of the publico industry. Therefore, the goal of the government is to improve publico service quality so it is comparable with the rest of the transit system, while recognizing the unique owner operator quality of the industry. This thesis examines four different jitney systems in North America. The study documents the development of the jitney service, how different cities govern jitney operators, and what affect the governance structure has on the quality of service. The purpose of this study is to determine what kind of governance structure leads to a high quality of jitney service. The study also examines what other factors contribute to high quality service. The ultimate goal is to apply the findings to San Juan, Puerto Rico in order to define future publico reforms. The case studies illustrate that North American jitney services all rely on hybrid governance models, consisting of government controls and self-regulating mechanisms. The study suggests that a hybrid governance structure that is based on cooperation between operators and government regulators leads to superior service quality. However, service quality is not merely a function of governance structure. Service quality also depends on the profitability of the jitney service, institutional strength, and the context of the industry. In a highly profitable setting, industry actors will spontaneously mobilize and provide a high quality of service. Consequently, the recommendations from this study examine ways of improving the profitability of the publico industry in order to improve the quality of service. In an unprofitable environment, the government must take the lead in developing other strategies to encourage service quality improvements. The recommendations in this study also suggests that the government proactively assist the publico industry improve service quality though various institutional and governance strategies.by Cybele T.Z. Chang.M.C.P

The evaluation of shear deformation for contact analysis with large displacement

A common problem encountered in the study of contact problem is the failure to obtain stable and accurate convergence result when the contact node is close to the element edge, which is referred as "critical area". In previous studies, the modification of the element force equation to apply it to a node-element contact problem using the Euler-Bernoulli beam theory [1]. A simple single-element consists two edges and a contact point was used to simulate contact phenomenon of a plane frame. The modification was proven to be effective by the convergeability of the unbalanced force at the tip of element edge, which enabled the contact node to "pass-through", resulting in precise results. However, in another recent study, we discover that, if shear deformation based on Timoshenko beam theory is taken into consideration, a basic simply supported beam coordinate afforded a much simpler and more efficient technique for avoiding the divergence of the unbalanced force in the "critical area". Using our unique and robust Tangent Stiffness Method, the improved equation can be used to overcome any geometrically nonlinear analyses, including those involving extremely large displacements

Characterization of the jabuticaba residue dehydrated and lyophilizated.

ISBN: 978-972-8936-28-0. I CLBHort. Editores Paulo César Tavares de Melo, António Calado. 1-4 nov. 2017

Low-loss slot waveguides with silicon (111) surfaces realized using anisotropic wet etching

We demonstrate low-loss slot waveguides on silicon-on-insulator (SOI) platform. Waveguides oriented along the (11-2) direction on the Si (110) plane were first fabricated by a standard e-beam lithography and dry etching process. A TMAH based anisotropic wet etching technique was then used to remove any residual side wall roughness. Using this fabrication technique propagation loss as low as 3.7dB/cm was realized in silicon slot waveguide for wavelengths near 1550nm. We also realized low propagation loss of 1dB/cm for silicon strip waveguides