Electromagnetic Radiation from Broken Symmetries in Relativistic Nuclear Collisions

A new channel of direct photon production from a quark gluon plasma (QGP) is explored in the framework of high-temperature QCD. This process appears at next-to-leading order, in the presence of a charge asymmetry in the excited matter. The photon production rate from this new mechanism is suppressed compared to the QCD annihilation and Compton scattering at low baryon density but assumes importance in baryon-rich matter.Comment: 6 pages, 3 figures, Contribution to the Quark Matter 2006 Conference in Shanghai, Nov 14-20 2006, to be submitted to International Journal of Modern Physics E (World Scientific

An open environment CT-US fusion for tissue segmentation during interventional guidance.

Therapeutic ultrasound (US) can be noninvasively focused to activate drugs, ablate tumors and deliver drugs beyond the blood brain barrier. However, well-controlled guidance of US therapy requires fusion with a navigational modality, such as magnetic resonance imaging (MRI) or X-ray computed tomography (CT). Here, we developed and validated tissue characterization using a fusion between US and CT. The performance of the CT/US fusion was quantified by the calibration error, target registration error and fiducial registration error. Met-1 tumors in the fat pads of 12 female FVB mice provided a model of developing breast cancer with which to evaluate CT-based tissue segmentation. Hounsfield units (HU) within the tumor and surrounding fat pad were quantified, validated with histology and segmented for parametric analysis (fat: -300 to 0 HU, protein-rich: 1 to 300 HU, and bone: HU>300). Our open source CT/US fusion system differentiated soft tissue, bone and fat with a spatial accuracy of ∼1 mm. Region of interest (ROI) analysis of the tumor and surrounding fat pad using a 1 mm(2) ROI resulted in mean HU of 68±44 within the tumor and -97±52 within the fat pad adjacent to the tumor (p<0.005). The tumor area measured by CT and histology was correlated (r(2) = 0.92), while the area designated as fat decreased with increasing tumor size (r(2) = 0.51). Analysis of CT and histology images of the tumor and surrounding fat pad revealed an average percentage of fat of 65.3% vs. 75.2%, 36.5% vs. 48.4%, and 31.6% vs. 38.5% for tumors <75 mm(3), 75-150 mm(3) and >150 mm(3), respectively. Further, CT mapped bone-soft tissue interfaces near the acoustic beam during real-time imaging. Combined CT/US is a feasible method for guiding interventions by tracking the acoustic focus within a pre-acquired CT image volume and characterizing tissues proximal to and surrounding the acoustic focus

Remarks on the Qin-Ma Parametrization of Quark Mixing Matrix

Recently, Qin and Ma (QM) have advocated a new Wolfenstein-like parametrization of the quark mixing matrix based on the triminimal expansion of the Cabibbo-Kobayashi-Maskawa (CKM) parametrization. The CP-odd phase in the QM parametrization is around $90^\circ$ just as that in the CKM parametrization. We point out that the QM parametrization can be readily obtained from the Wolfenstein parametrization after appropriate phase redefinition for quark fields and that the phase $\delta$ in both QM and CKM parametrizations is related to the unitarity angles $\alpha$, $\beta$ and $\gamma$, namely, $\delta= \beta+\gamma$ or $\pi-\alpha$. We show that both QM and Wolfenstein parametrizations can be deduced from the CKM and Chau-Keung-Maiani ones. By deriving the QM parametrization from the Fritzsch-Xing (FX) parametrization of the quark mixing matrix, we find that the phase of the FX form is in the vicinity of $-270^\circ$ and hence $\sin\delta\approx 1$. We discuss the seeming discrepancy between the Wolfenstein and QM parametrizations at the high order of $\lambda\approx |V_{us}|$.Comment: 8 pages, a shortened version accepted by PL

Incarceration and Unwed Fathers in Fragile Families

Criminal justice policies have resulted in millions of Americans being incarcerated over the past three decades in systems that provide little or no rehabilitation. This study uses a new dataset-The Fragile Families Study-to document poor labor market outcomes that are associated with incarceration. We find that fathers who had been incarcerated earned 28 percent less annually thanfathers who were never incarceratedT hese previously incarceratedfa thers worked less weeks per year, less hours per week and were less likely to be working during the week prior to their interview. We also found that fathers who had been incarcerated were more likely to depend on underground employment and off-the-books earnings

The Role of National Culture on Relationships Between Customers’ Perception of Quality, Values, Satisfaction, and Behavioral Intentions

The purpose of this paper is to examine the influence of individualistic cultures (such as the American culture) and collectivistic cultures (such as the Chinese culture) on the interrelationship among service quality, food quality, perceived value, customer satisfaction, and behavioral intentions in the fast-food industry. First, the authors provide empirical evidence of the robust relationships among the constructs across diverse cultures. Second, they investigate how moderator variables such as customer age, gender, and national culture affect customer behavioral intentions. Moreover, they examine how national culture, as a moderator, affects the magnitude of the relationships among these constructs. Using survey data collected from the United States and China, results indicate that national culture does have a moderating effect on the relationships and there are differences in the behavioral intentions of American and Chinese customers. More specifically, in the United States, service quality and food quality have a stronger influence on customer satisfaction than in China. Also, the effect of perceived value on customer satisfaction and the effect of customer satisfaction on customers’ behavioral intentions are stronger in China than in the United States. Overall, the findings provide rare crosscultural insights and thus serve as building blocks for strategies in the global fast-food domain

Radiative and Collisional Jet Energy Loss in the Quark-Gluon Plasma at RHIC

We calculate and compare bremsstrahlung and collisional energy loss of hard partons traversing a quark-gluon plasma. Our treatment of both processes is complete at leading order in the coupling and accounts for the probabilistic nature of the jet energy loss. We find that the nuclear modification factor $R_{AA}$ for neutral $\pi^0$ production in heavy ion collisions is sensitive to the inclusion of collisional and radiative energy loss contributions while the averaged energy loss only slightly increases if collisional energy loss is included for parent parton energies $E\gg T$. These results are important for the understanding of jet quenching in Au+Au collisions at $200 {\rm AGeV}$ at RHIC. Comparison with data is performed applying the energy loss calculation to a relativistic ideal (3+1)-dimensional hydrodynamic description of the thermalized medium formed at RHIC.Comment: 4 pages, 3 figure

Phase III, Randomized, Double-Blind, Placebo-Controlled Evaluation of Pregabalin for Alleviating Hot Flashes, N07C1

PURPOSE: Hot flashes are a common problem for which effective and safe treatments are needed. The current trial was conducted on the basis of preliminary promising data that pregabalin decreased hot flashes. PATIENTS AND METHODS: A double-blind, placebo-controlled, randomized trial design was used to compare pregabalin at target doses of 75 mg twice daily and 150 mg twice daily with a placebo. Hot flash frequencies and scores (frequency times mean severity) were recorded daily during a baseline week and for six treatment weeks. The primary end point for this study was the change-from-baseline hot flash score during treatment week 6 between the 150 mg twice daily target pregabalin treatment and placebo. Nonparametric Wilcoxon rank sum tests, two-sample t tests, and chi(2) tests were used to compare the primary and secondary hot flash efficacy end points between pregabalin treatments and placebo. RESULTS: Hot flash score changes available for 163 patients during the sixth treatment week compared with a baseline week decreased by 50%, 65%, and 71% in the placebo, and target 75 mg twice daily and 150 mg twice daily pregabalin arms, respectively (P = .009 and P = .007, comparing respective pregabalin arms to the placebo arm). While some toxicities were significantly more common in the pregabalin arms, being more evident with the higher dose, pregabalin was generally well tolerated by most patients. CONCLUSION: Pregabalin decreases hot flashes and is reasonably well tolerated. A target dose of 75 mg twice daily is recommended. Its effects appear to be roughly comparable to what has been reported with gabapentin and with some newer antidepressant

How Sample Completeness Affects Gamma-Ray Burst Classification

Unsupervised pattern recognition algorithms support the existence of three gamma-ray burst classes; Class I (long, large fluence bursts of intermediate spectral hardness), Class II (short, small fluence, hard bursts), and Class III (soft bursts of intermediate durations and fluences). The algorithms surprisingly assign larger membership to Class III than to either of the other two classes. A known systematic bias has been previously used to explain the existence of Class III in terms of Class I; this bias allows the fluences and durations of some bursts to be underestimated (Hakkila et al., ApJ 538, 165, 2000). We show that this bias primarily affects only the longest bursts and cannot explain the bulk of the Class III properties. We resolve the question of Class III existence by demonstrating how samples obtained using standard trigger mechanisms fail to preserve the duration characteristics of small peak flux bursts. Sample incompleteness is thus primarily responsible for the existence of Class III. In order to avoid this incompleteness, we show how a new dual timescale peak flux can be defined in terms of peak flux and fluence. The dual timescale peak flux preserves the duration distribution of faint bursts and correlates better with spectral hardness (and presumably redshift) than either peak flux or fluence. The techniques presented here are generic and have applicability to the studies of other transient events. The results also indicate that pattern recognition algorithms are sensitive to sample completeness; this can influence the study of large astronomical databases such as those found in a Virtual Observatory.Comment: 29 pages, 6 figures, 3 tables, Accepted for publication in The Astrophysical Journa

Interventions that Increase Enrolment of Women in Higher Education: The University of Dar es Salaam, Tanzania

Gender equality and equity has long been a focus area in Tanzanian government, encouraging the increased recruitment of female students in to higher education. This article investigates the effectiveness of affirmative action policy interventions that introduced and designed to increase female students' enrolment at the University of Dar es Salaam. The study based on the data obtained from University of Dar es Salaam records and report, documentary of key policies, online articles, publications and ministry of higher education website. Using the case of the University of Dar es Salaam (UDSM) was justified by, is the oldest and largest institution of higher education in Tanzania that has a large in terms population and offers a verity of disciplines in both science and Humanities. The findings from this study reveal that affirmative action policy interventions have positive effect towards increasing recruitment female students at the University of Dar es salaam. However the date shows that the number of female students is still low in Sciences and Engineering disciplines compared to that of their male peers. This suggests that men dominated all specializations in the faculty of science. Keywords: Gender equity, Access to high education, Affirmative actio