The Pope John XXIII Lecture

This Pope John XXIII Lecture was given March 20, 1997 at The Catholic University of America, Columbus School of Law in Washington, D.C

The Pope John XXIII Lecture

This Pope John XXIII Lecture was given March 20, 1997 at The Catholic University of America, Columbus School of Law in Washington, D.C

Photon antibunching in the fluorescence of individual color centers in diamond

We have observed photon antibunching in the fluorescence light emitted from a single N-V center in diamond at room temperature. The possibility of generating triggerable single photons with such a solide state system is discussedComment: 4 pages, 4 figure

Automatic correction of dental artifacts in PET/MRI

A challenge when using current magnetic resonance (MR)-based attenuation correction in positron emission tomography/MR imaging (PET/MRI) is that the MRIs can have a signal void around the dental fillings that is segmented as artificial air-regions in the attenuation map. For artifacts connected to the background, we propose an extension to an existing active contour algorithm to delineate the outer contour using the nonattenuation corrected PET image and the original attenuation map. We propose a combination of two different methods for differentiating the artifacts within the body from the anatomical air-regions by first using a template of artifact regions, and second, representing the artifact regions with a combination of active shape models and k-nearest-neighbors. The accuracy of the combined method has been evaluated using 25 [Formula: see text]-fluorodeoxyglucose PET/MR patients. Results showed that the approach was able to correct an average of [Formula: see text] of the artifact areas

Reduction versus abrupt cessation in smokers who want to quit.

Background\ud The standard way to stop smoking is to quit abruptly on a designated quit day. A number of smokers have tried unsuccessfully to quit this way. Reducing smoking before quitting could be an alternative approach to cessation. Before this method is adopted it is important to determine whether it is at least as successful as abrupt quitting.\ud \ud Objectives\ud 1. To compare the success of reducing smoking to quit and abrupt quitting interventions. 2. To compare adverse events between arms in studies that used pharmacotherapy to aid reduction.\ud \ud Search methods\ud We searched the Cochrane Tobacco Addiction Review Group specialised register, MEDLINE, EMBASE and PsycInfo for topic specific terms combined with terms used to identify trials of tobacco addiction interventions. We also searched reference lists of relevant papers and contacted authors of ongoing trials. Date of most recent search: November 2009.\ud \ud Selection criteria\ud We included randomized controlled trials (RCTs) that recruited adults who wanted to quit smoking. Studies included at least one condition which instructed participants to reduce their smoking and then quit and one condition which instructed participants to quit abruptly.\ud \ud Data collection and analysis\ud The outcome measure was abstinence from smoking after at least six months follow-up. We pooled the included trials using a Mantel-Haenszel fixed-effect model. Trials were split for two sub-group analyses: pharmacotherapy vs no pharmacotherapy, self help therapy vs behavioural support. Adverse events were summarised as a narrative. It was not possible to compare them quantitatively as there was variation in the nature and depth of reporting across studies.\ud \ud Main results\ud Ten studies were relevant for inclusion, with a total of 3760 participants included in the meta-analysis. Three of these studies used pharmacotherapy as part of the interventions. Five studies included behavioural support in the intervention, four included self-help therapy, and the remaining study had arms which included behavioural support and arms which included self-help therapy. Neither reduction or abrupt quitting had superior abstinence rates when all the studies were combined in the main analysis (RR= 0.94, 95% CI= 0.79 to 1.13), whether pharmacotherapy was used (RR= 0.87, 95% CI= 0.65 to 1.22), or not (RR= 0.97, 95% CI= 0.78 to 1.21), whether studies included behavioural support (RR= 0.87, 95% CI= 0.64 to 1.17) or self-help therapy (RR= 0.98, 95% CI= 0.78 to1.23). We were unable to draw conclusions about the difference in adverse events between interventions, however recent studies suggest that pre-quit NRT does not increase adverse events.\ud \ud Authors' conclusions\ud Reducing cigarettes smoked before quit day and quitting abruptly, with no prior reduction, produced comparable quit rates, therefore patients can be given the choice to quit in either of these ways. Reduction interventions can be carried out using self-help materials or aided by behavioural support, and can be carried out with the aid of pre-quit NRT. Further research needs to investigate which method of reduction before quitting is the most effective, and which categories of smokers benefit the most from each method, to inform future policy and intervention development.\ud \u

Single photon generation by pulsed excitation of a single dipole

The fluorescence of a single dipole excited by an intense light pulse can lead to the generation of another light pulse containing a single photon. The influence of the duration and energy of the excitation pulse on the number of photons in the fluorescence pulse is studied. The case of a two-level dipole with strongly damped coherences is considered. The presence of a metastable state leading to shelving is also investigated.Comment: 17 pages, 4 figures, submitted to PR

XVII International AIDS Conference: From Evidence to Action - Social, behavioural and economic science and policy and political science

AIDS 2008 firmly established stigma and discrimination as fundamental priorities in the push for universal access to HIV prevention, treatment, care and support. Conference sessions and discussions reinforced the tangible negative effects of stigma on national legislation and policies. A strong theme throughout the conference was the need to replace prevention interventions that focus exclusively on individual behaviour change or biomedical prevention interventions with "combination prevention" approaches that address both individual and structural factors that increase vulnerability to HIV infection