Photoassociative Frequency Shift in a Quantum Degenerate Gas

We observe a light-induced frequency shift in single-photon photoassociative spectra of magnetically trapped, quantum degenerate 7Li. The shift is a manifestation of the coupling between the threshold continuum scattering states and discrete bound levels in the excited-state molecular potential induced by the photoassociation laser. The frequency shift is observed to be linear in the laser intensity with a measured proportionality constant that is in good agreement with theoretical predictions. The frequency shift has important implications for a scheme to alter the interactions between atoms in a Bose-Einstein condensate using photoassociation resonances.Comment: 3 figure

Measuring energy spectra of TeV gamma-ray emission from the Cygnus region of our galaxy with Milagro

High energy gamma rays can provide fundamental clues to the origins of cosmic rays. In this thesis, TeV gamma-ray emission from the Cygnus region is studied. Previously the Milagro experiment detected five TeV gamma-ray sources in this region and a significant excess of TeV gamma rays whose origin is still unclear. To better understand the diffuse excess the separation of sources and diffuse emission is studied using the latest and most sensitive data set of the Milagro experiment. In addition, a newly developed technique is applied that allows the energy spectrum of the TeV gamma rays to be reconstructed using Milagro data. No conclusive statement can be made about the spectrum of the diffuse emission from the Cygnus region because of its low significance of 2.2 σ above the background in the studied data sample. The entire Cygnus region emission is best fit with a power law with a spectral index of α=2.40 (68% confidence interval: 1.35-2.92) and a exponential cutoff energy of 31.6 TeV (10.0-251.2 TeV). In the case of a simple power law assumption without a cutoff energy the best fit yields a spectral index of α=2.97 (68% confidence interval: 2.83-3.10). Neither of these best fits are in good agreement with the data. The best spectral fit to the TeV emission from MGRO J2019+37, the brightest source in the Cygnus region, yields a spectral index of α=2.30 (68% confidence interval: 1.40-2.70) with a cutoff energy of 50.1 TeV (68% confidence interval: 17.8-251.2 TeV) and a spectral index of α=2.75 (68% confidence interval: 2.65-2.85) when no exponential cutoff energy is assumed. According to the present analysis, MGRO J2019+37 contributes 25% to the differential flux from the entire Cygnus at 15 TeV

Telecommunications reform in Malawi

In 1998 the Government of Malawi decided to reform its telecommunications sector. Although the reform was ambitious in some ways, it was modest when compared with the most ambitious reforms adopted elsewhere in Sub-Saharan Africa. The two main accomplishments were splitting the incumbent fixed line monopoly, the Malawi Post and Telecommunications Corporation, into two companies-Malawi Telecommunications Limited (MTL) and Malawi Post Corporation (MPC)-and issuing two new cellular licenses to two new private entrants. In addition, the Government also established a new regulator which was separate from, but heavily dependent on, the Ministry of Information and liberalized entry in value-added and Internet services. However, the Government had neither privatized the fixed-line telecommunications operator nor introduced competition in fixed-line services by the end of 2002. Clarke, Gebreab, and Mgombelo discuss sector performance before reform, details of the reform, the political motivation for reform, and events in the five years following the reform. The reform yielded mixed results. Although cellular penetration and Internet use expanded dramatically following reform, prices increased, especially for cellular calls, and fixed-line penetration remains low by regional standards.Public Sector Economics&Finance,Rural Communications,Telecommunications Infrastructure,ICT Policy and Strategies,Knowledge Economy,ICT Policy and Strategies,Rural Communications,Education for the Knowledge Economy,Knowledge Economy,Public Sector Economics&Finance

The binary fraction of planetary nebula central stars I. A high-precision, I-band excess search

In an attempt to determine how many planetary nebulae derive from binary interactions, we have started a project to measure their unbiased binary fraction. This number, when compared to the binary fraction of the presumed parent population can give a first handle on the origin of planetary nebulae. By detecting 27 bona fide central stars in the I band we have found that 30% of our sample have an I band excess between one and a few sigmas, possibly denoting companions brighter than M3-4V and with separations smaller than approximately 1000 AU. By accounting for the undetectable companions, we determine a de-biased binary fraction of 67-78% for all companions at all separations. We compare this number to a main sequence binary fraction of (50+/-4)% determined for spectral types F6V-G2V, appropriate if the progenitors of today's PN central star population is indeed the F6V-G2V stars. The error on our estimate could be between 10 and 30%. We conclude that the central star binary fraction may be larger than expected from the putative parent population. Using the more sensitive J band of a subset of 11 central stars, the binary fraction is 54% for companions brighter than approximately M5-6V and with separations smaller than about 900 AU. De-biassing this number we obtain a binary fraction of 100-107%. The two numbers should be the same and the discrepancy is likely due to small number statistics. We also present an accurately vetted compilation of observed main sequence star magnitudes, colours and masses, which can serve as a reference for future studies. We also present synthetic colours of hot stars as a function of temperature (20-170kK) and gravity (log g= 6-8) for Solar and PG1159 compositions.Comment: 22 pages, 6 figures, 12 tables, accepted by MNRA

Man and Superman : Waltzes

https://digitalcommons.library.umaine.edu/mmb-ps/2765/thumbnail.jp

Assessment of the user characteristics of the out- patient service of Jimma Hospital

Abstract: A survey to assess users' characteristics of the out-patient (OPD) Service of Jimma Hospital (South West Ethiopia) was undertaken during 1-15 August 1993. A total of 1256 patients who reported to OPD services during the day and night, including emergency hours, were interviewed using a structured questionnaire to examine socio-demographic factors, reasons for hospital visit and others. Among the 1256 interviewed 76.6% were from Jimma town and 12.7% were referred from other health institutions, 52.9% were females; 63.5% were married; 7.3% have a family size of > 10 and 74.5% patients travelled for less than one hour while 2.6% travelled more than 12 hours to reach the Hospital. It was also found out that 11.8%,49.3% and 11.8% sought medical help within 24 hours, 1-7 weeks and 12 weeks, respectively. Age, sex and inefficient referral system were found to have significant effect on the utilization of the OPD services of Jimma Hospital. [Ethiop. I. Health Dev. 1996;10(2):111-115

Testing the binary hypothesis for the formation and shaping of planetary nebulae

There is no quantitative theory to explain why a high 80% of all planetary nebulae are non-spherical. The Binary Hypothesis states that a companion to the progenitor of a central star of planetary nebula is required to shape the nebula and even for a planetary nebula to be formed at all. A way to test this hypothesis is to estimate the binary fraction of central stars of planetary nebulae and to compare it with that of the main sequence population. Preliminary results from photometric variability and the infrared excess techniques indicate that the binary fraction of central stars of planetary nebulae is higher than that of the main sequence, implying that PNe could preferentially form via a binary channel. This article briefly reviews these results and current studies aiming to refine the binary fraction.Comment: EUROWD12 Proceeding

Planetary nebulae : getting closer to an unbiased binary fraction

Why 80% of planetary nebulae are not spherical is not yet understood. The Binary Hypothesis states that a companion to the progenitor of the central star of a planetary nebula is required to shape the nebula and even for a planetary nebula to be formed at all. A way to test this hypothesis is to estimate the binary fraction of central stars of planetary nebula and to compare it with the main sequence population. Preliminary results from photometric variability and infrared excess techniques indicate that the binary fraction of central stars of planetary nebulae is higher than that of the putative main sequence progenitor population, implying that PNe could be preferentially formed via a binary channel. This article briefly reviews these results and future studies aiming to refine the binary fraction.Comment: SF2A 2012 proceeding

The Vacancy Rate and Rent Levels in the Commercial Office Market

This paper develops and estimates a cross-sectional model of the commercial office market in which the building vacancy rate is a key factor in the determination of rents. Individual buildings in Greensboro, North Carolina are used as the unit of analysis and simultaneous equation procedures are employed to produce estimates of rent per square foot. The estimates confirm that the vacancy rate must be included when estimating the price of commercial office space.

Geobase Information System Impacts on Space Image Formats

As Geobase Information Systems increase in number, size and complexity, the format compatability of satellite remote sensing data becomes increasingly more important. Because of the vast and continually increasing quantity of data available from remote sensing systems the utility of these data is increasingly dependent on the degree to which their formats facilitate, or hinder, their incorporation into Geobase Information Systems. To merge satellite data into a geobase system requires that they both have a compatible geographic referencing system. Greater acceptance of satellite data by the user community will be facilitated if the data are in a form which most readily corresponds to existing geobase data structures. The conference addressed a number of specific topics and made recommendations