Leptoquarks decaying to a top quark and a charged lepton at hadron colliders

We study the sensitivity of the Tevatron and the 7 TeV LHC to a leptoquark S coupling to a top quark and a charged lepton L (= e, mu, or tau). For the Tevatron, we focus on the case m_S < m_t, where the leptoquark pair production cross section is large, and the decay is three-body: S --> W b L^{\pm}. We argue that existing Tevatron observations could exclude m_S \lsim 160 GeV. For m_S > m_t, we show that the LHC experiments with low integrated luminosity could be sensitive to such leptoquarks decaying to tl^{\pm} with l= mu or tau.Comment: 13 pages, 6 figures, minor changes (typos

Oral History Interview on Education/Instruccion, part 2

Julia Ramos Grenier recalls her experience as a co-director of Education/Instruccion, a civil rights advocacy group based in Hartford, Connecticut, with Ben Dixon and Boyd Hinds. She describes her work in challenging housing discrimination with the Ya Basta project (translated as Enough already ), including organizing volunteers to pose as home buyers in different Hartford and suburban neighborhoods to compare how real estate firms steered racial and language minorities toward specific areas. She also recounts more about the Westledge School and her activism at stockholder board meetings of insurance corporations based in Hartford

Oral History Interview on Education/Instruccion, part 1

Dr. Julia Ramos Grenier recalls her time working as co-director of Education/Instruccion, a civil rights advocacy group based in Hartford, Connecticut. As a young Puerto Rican woman, she speaks about how she met the other co-directors (Boyd Hinds and Ben Dixon, at Westledge School in West Simsbury) and their work on challenging institutional racism and housing discrimination. She also describes obtaining her prior role with anti-poverty programs, earning her PhD in psychology, her work with multicultural consulting at The Travelers insurance company, her time with the Hartford Community Mental Health Center, her studies with Brazilian educator Paulo Freire, and her interactions with other Hispanic community leaders in Hartford

Magnetization Measurements on Single Crystals of Superconducting Ba0.6K0.4BiO3

Extensive measurements of the magnetization of superconducting single crystal samples of Ba0.6K0.4BiO3} have been made using SQUID and cantilever force magnetometry at temperatures ranging between 1.3 and 350 K and in magnetic fields from near zero to 27 T. Hysteresis curves of magnetization versus field allow a determination of the thermodynamic critical field, the reversibility field, and the upper critical field as a function of temperature. The lower critical field is measured seperately and the Ginzburg-Landau parameter is found to be temperature dependent. All critical fields have higher T = 0 limits than have been previously noted and none of the temperature dependence of the critical fields follow the expected power laws leading to possible alternate interpretation of the thermodynamic nature of the superconducting transition.Comment: 33 pages, 11 figures, accepted for publication in Philosophical Magazine B on 7 August 1999. This paper supplies the experimental details for the argument presented in our PRL 82 (1999) p. 4532-4535 (also at cond-mat/9904288

Social determinants of health and health inequities in Nakuru (Kenya)

<p>Abstract</p> <p>Background</p> <p>Dramatic inequalities dominate global health today. The rapid urban growth sustained by Kenya in the last decades has created many difficulties that also led to worsening inequalities in health care. The continuous decline in its Human Development Index since the 1990s highlights the hardship that continues to worsen in the country, against the general trend of Sub-Saharan Africa. This paper examines the health status of residents in a major urban centre in Kenya and reviews the effects of selected social determinants on local health.</p> <p>Methods</p> <p>Through field surveys, focus group discussions and a literature review, this study canvasses past and current initiatives and recommends priority actions.</p> <p>Results</p> <p>Areas identified which unevenly affect the health of the most vulnerable segments of the population were: water supply, sanitation, solid waste management, food environments, housing, the organization of health care services and transportation.</p> <p>Conclusion</p> <p>The use of a participatory method proved to be a useful approach that could benefit other urban centres in their analysis of social determinants of health.</p

Cosmic-ray propagation properties for an origin in SNRs

We have studied the impact of cosmic-ray acceleration in SNR on the spectra of cosmic-ray nuclei in the Galaxy using a series expansion of the propagation equation, which allows us to use analytical solutions for part of the problem and an efficient numerical treatment of the remaining equations and thus accurately describes the cosmic-ray propagation on small scales around their sources in three spatial dimensions and time. We found strong variations of the cosmic-ray nuclei flux by typically 20% with occasional spikes of much higher amplitude, but only minor changes in the spectral distribution. The locally measured spectra of primary cosmic rays fit well into the obtained range of possible spectra. We further showed that the spectra of the secondary element Boron show almost no variations, so that the above findings also imply significant fluctuations of the Boron-to-Carbon ratio. Therefore the commonly used method of determining CR propagation parameters by fitting secondary-to-primary ratios appears flawed on account of the variations that these ratios would show throughout the Galaxy.Comment: Accepted for publication in Ap

The EGRET sky: a new interstellar emission model and source detection

The comparison of HI, CO, dust, and gamma-ray maps in the solar neighborhood has led to the discovery of large amounts of dark gas. The large mass and angular extent of the local dark clouds, as well as their clumpiness, imply severe revisions of the interstellar emission model to high latitudes, therefore of the detectability of a point-source above the diffuse background. We have used this new model to search for point-like sources at 5\degres$\leq$|b|$_leq$80\degres and we show that numerous persistent unidentified EGRET sources are not confirmed as significant sources

Social determinants of health in Tunisia: the case-analysis of Ariana

<p>Abstract</p> <p>Background</p> <p>Few research projects have analyzed how social determinants of health impact cities in North Africa. The sustained growth in these countries has nevertheless proven to exacerbate health disparities and create many social and economic inequalities. This strategic analysis examines selected social determinants of health in a major urban centre of Tunisia, identifies the most influential stakeholders able to influence equity/inequity, and reviews the accomplishments and need for action to foster health equity.</p> <p>Methods</p> <p>This analysis was performed through a literature review and participatory research methods that included focus groups discussions and interview with key informants.</p> <p>Results</p> <p>Access to health care, changes in lifestyles, housing issues and gender-related inequities are prime, socially-determined elements that affect health in Ariana.</p> <p>Conclusion</p> <p>Recognition of emerging health issues is needed along with improved inter and intrasectoral coordination among stakeholders. The community-participatory approach used in this paper proved to be a useful scoping technique for this setting. A similar methodology could be used by other researchers as a first step toward health equity action at a city level.</p

Normal State Magnetic Properties of Ni and Zn Substituted in YBa_{2}Cu_{3} O_{6+x}: Hole-Doping Dependence

We present SQUID susceptibility data on Zn and Ni substituted YBa_{2}Cu_{3}O_{6+x}. Cross-checks with NMR yield an unprecedented accuracy in the estimate of the magnetic susceptibility associated with the substituants, from the underdoped to the lightly overdoped case. This allows us to determine the Weiss temperature \theta for YBCO: its value is very small for all hole dopings n_h. Since in conventional metals, the Kondo temperature, $T_{K}<\theta$, magnetic screening effects would not be expected for $T\gg \theta$; in contrast, increasing n_h produces a reduction of the small moment induced by Zn^{2+} and a nearly constant effective moment for Ni^{2+} corresponding to a spin 1/2 rather than to a spin 1.Comment: 4 pages, 5 figures, to be published in Europhysics Letter