Reconstructing the Star Formation History of the Galaxy

The evolution of the star formation rate in the Galaxy is one of the key ingredients quantifying the formation and determining the chemical and luminosity evolution of galaxies. Many complementary methods exist to infer the star formation history of the components of the Galaxy, from indirect methods for analysis of low-precision data, to new exact analytic methods for analysis of sufficiently high quality data. We summarise available general constraints on star formation histories, showing that derived star formation rates are in general comparable to those seen today. We then show how colour-magnitude diagrams of volume- and absolute magnitude-limited samples of the solar neighbourhood observed by Hipparcos may be analysed, using variational calculus techniques, to reconstruct the local star formation history. The remarkable accuracy of the data coupled to our maximum-likelihood variational method allows objective quantification of the local star formation history with a time resolution of ~ 50 Myr. Over the past 3Gyr, the solar neighbourhood star formation rate has varied by a factor of ~ 4, with characteristic timescale about 0.5Gyr, possibly triggered by interactions with spiral arms.Comment: 12 pages, Proc. of the Sept. 20-24, 1999 Vulcano Workshop ``The chemical evolution of the Milky Way: stars vs. clusters'', eds. F. Matteucci & F. Giovanell

Randomized clinical trial of a phytotherapic compound containing <it>Pimpinella anisum</it>, <it>Foeniculum vulgare</it>, <it>Sambucus nigra</it>, and <it>Cassia augustifolia </it>for chronic constipation

<p>Abstract</p> <p>Background</p> <p>A phytotherapic compound containing <it>Pimpinella anisum </it>L., <it>Foeniculum vulgare </it>Miller, <it>Sambucus nigra </it>L., and Cassia <it>augustifolia </it>is largely used in Brazil for the treatment of constipation. However, the laxative efficacy of the compound has never been tested in a randomized clinical trial. The aim of this study was to evaluate the efficacy and safety of the product.</p> <p>Methods</p> <p>This randomized, crossover, placebo-controlled, single-blinded trial included 20 patients presenting with chronic constipation according to the criteria of the American Association of Gastroenterology. The order of treatments was counterbalanced across subjects: half of the subjects received the phytotherapic compound for a 5-day period, whereas the other half received placebo for the same period. Both treatment periods were separated by a 9-day washout period followed by the reverse treatment for another 5-day period. The primary endpoint was colonic transit time (CTT), measured radiologically. Secondary endpoints included number of evacuations per day, perception of bowel function, adverse effects, and quality of life.</p> <p>Results</p> <p>Mean CTT assessed by X ray was 15.7 hours (95%CI 11.1-20.2) in the active treatment period and 42.3 hours (95%CI 33.5-51.1) during the placebo treatment (p < 0.001). Number of evacuations per day increased during the use of active tea; significant differences were observed as of the second day of treatment (p < 0.001). Patient perception of bowel function was improved (p < 0.01), but quality of life did not show significant differences among the study periods. Except for a small reduction in serum potassium levels during the active treatment, no significant differences were observed in terms of adverse effects throughout the study period.</p> <p>Conclusions</p> <p>The findings of this randomized controlled trial allow to conclude that the phytotherapic compound assessed has laxative efficacy and is a safe alternative option for the treatment of constipation.</p> <p>Trial registration</p> <p>ClinicalTrial.gov NCT00872430</p

The RaDIANT community study protocol: community-based participatory research for reducing disparities in access to kidney transplantation

BACKGROUND: The Southeastern United States has the lowest kidney transplant rates in the nation, and racial disparities in kidney transplant access are concentrated in this region. The Southeastern Kidney Transplant Coalition (SEKTC) of Georgia, North Carolina, and South Carolina is an academic and community partnership that was formed with the mission to improve access to kidney transplantation and reduce disparities among African American (AA) end stage renal disease (ESRD) patients in the Southeastern United States. METHODS/DESIGN: We describe the community-based participatory research (CBPR) process utilized in planning the Reducing Disparities In Access to kidNey Transplantation (RaDIANT) Community Study, a trial developed by the SEKTC to reduce health disparities in access to kidney transplantation among AA ESRD patients in Georgia, the state with the lowest kidney transplant rates in the nation. The SEKTC Coalition conducted a needs assessment of the ESRD population in the Southeast and used results to develop a multicomponent, dialysis facility-randomized, quality improvement intervention to improve transplant access among dialysis facilities in GA. A total of 134 dialysis facilities are randomized to receive either: (1) standard of care or “usual” transplant education, or (2) the multicomponent intervention consisting of transplant education and engagement activities targeting dialysis facility leadership, staff, and patients within dialysis facilities. The primary outcome is change in facility-level referral for kidney transplantation from baseline to 12 months; the secondary outcome is reduction in racial disparity in transplant referral. DISCUSSION: The RaDIANT Community Study aims to improve equity in access to kidney transplantation for ESRD patients in the Southeast. TRIAL REGISTRATION: Clinicaltrials.gov number NCT02092727