High resolution images of P/Tempel 1 and P/Tempel 2 constructed from IRAS survey data

Infrared images of P/Tempel 1 and P/Tempel 2 were constructed from IRAS survey data using a computer algorithm based on the Maximum Correlation Method for Image Construction (Aumann et al, 1990). The resulting images are of sufficiently high quality and resolution to delineate coma and tail morphology, and permit accurate photometry of the total dust complex. Comparisons of the infrared colors and photometric profiles of Tempel 1 and Tempel 2 at similar heliocentric distances show that the grains produced by the two comets are quite similar in radiometric and dynamic properties. Tempel 1 is found to produce about 30 percent more dust in its coma and tail than Tempel 2. The comae of Tempel 1 and Tempel 2 are expanding with mean velocities of 5.8 plus or minus 0.07 and 6.1 plus or minus 0.17 m/sec respectively, indicative of the ejection of large grains. The IRAS cataloged infrared fluxes (Walker, 1986) are found to be underestimated by as much as a factor of three for the comets. Therefore, it is essential to create images of the comets to obtain meaningful IRAS photometry

Revealing the Changing Spatial Structure of Cities from Human Activity Patterns

Identifying changes in the spatial structure of cities is a prerequisite for the development and validation of adequate planning strategies. Nevertheless, current methods of measurement are becoming ever more challenged by the highly diverse and intertwined ways of how people actually make use of urban space. Here, we propose a new quantitative measure for the centrality of locations, taking into account not only the numbers of people attracted to different locations, but also the diversity of the activities they are engaged in. This ‘centrality index’ allows for the identification of functional urban centres and for a systematic tracking of their relative importance over time, thus contributing to our understanding of polycentricity. We demonstrate the proposed index using travel survey data in Singapore for different years between 1997 and 2012. It is shown that, on the one hand, the city-state has been developing rapidly towards a polycentric urban form that compares rather closely with the official urban development plan. On the other hand, however, the downtown core has strongly gained in its importance, and this can be partly attributed to the recent extension of the public transit system

Novel bleeding risk score for patients with atrial fibrillation on oral anticoagulants, including direct oral anticoagulants

Objective: Balancing bleeding risk and stroke risk in patients with atrial fibrillation (AF) is a common challenge. Though several bleeding risk scores exist, most have not included patients on direct oral anticoagulants (DOACs). We aimed at developing a novel bleeding risk score for patients with AF on oral anticoagulants (OAC) including both vitamin K antagonists (VKA) and DOACs. Methods: We included patients with AF on OACs from a prospective multicenter cohort study in Switzerland (SWISS-AF). The outcome was time to first bleeding. Bleeding events were defined as major or clinically relevant non-major bleeding. We used backward elimination to identify bleeding risk variables. We derived the score using a point score system based on the β-coefficients from the multivariable model. We used the Brier score for model calibration (<0.25 indicating good calibration), and Harrel's c-statistics for model discrimination. Results: We included 2147 patients with AF on OAC (72.5% male, mean age 73.4 ± 8.2 years), of whom 1209 (56.3%) took DOACs. After a follow-up of 4.4 years, a total of 255 (11.9%) bleeding events occurred. After backward elimination, age > 75 years, history of cancer, prior major hemorrhage, and arterial hypertension remained in the final prediction model. The Brier score was 0.23 (95% confidence interval [CI] 0.19–0.27), the c-statistic at 12 months was 0.71 (95% CI 0.63–0.80). Conclusion: In this prospective cohort study of AF patients and predominantly DOAC users, we successfully derived a bleeding risk prediction model with good calibration and discrimination

Bordetella pertussis Infection or Vaccination Substantially Protects Mice against B. bronchiseptica Infection

Although B. bronchiseptica efficiently infects a wide range of mammalian hosts and efficiently spreads among them, it is rarely observed in humans. In contrast to the many other hosts of B. bronchiseptica, humans are host to the apparently specialized pathogen B. pertussis, the great majority having immunity due to vaccination, infection or both. Here we explore whether immunity to B. pertussis protects against B. bronchiseptica infection. In a murine model, either infection or vaccination with B. pertussis induced antibodies that recognized antigens of B. bronchiseptica and protected the lower respiratory tract of mice against three phylogenetically disparate strains of B. bronchiseptica that efficiently infect naïve animals. Furthermore, vaccination with purified B. pertussis-derived pertactin, filamentous hemagglutinin or the human acellular vaccine, Adacel, conferred similar protection against B. bronchiseptica challenge. These data indicate that individual immunity to B. pertussis affects B. bronchiseptica infection, and suggest that the high levels of herd immunity against B. pertussis in humans could explain the lack of observed B. bronchiseptica transmission. This could also explain the apparent association of B. bronchiseptica infections with an immunocompromised state

Stimulation cardiaque. Extraction percutanee de sondes infectees. [Cardiac pacing. Percutaneous extraction of infected pacing catheter]

Infection of a cardiac pacemaker is a rare but serious complication. Percutaneous ablation of the pacemaker and pacing catheter is the only effective treatment. Techniques of extraction of pacing systems have been evaluated but the long term results require analysis. Eighteen patients with infection of cardiac pacemakers underwent extraction of one or more pacing catheters (14 atrial and 20 ventricular) in one same centre. The indication was infection of the pacemaker unit (12 cases) or septicaemia (6 cases) The causal organism was a staphylococcus (aureus: 7 cases, epidermidis: 10 cases, capitis: 1 case). Three techniques were used: 1) direct external manual traction, 2) internal traction with several devices, 3) endovascular counter-traction (Byrd-Cook system). The time from primary implantation of the pacing catheter to its extraction was 42 months and from last pacemaker manipulation to infection, 23 months. The average duration of the extraction procedure was 120 +/- 45 minutes; that of fluoroscopy was 10 +/- 6 minutes. The first technique was used 12 times, the second 8 times and the third 14 times, with complete extraction of the catheter in 88.2% of cases. The metallic tip of the distal electrode embolised in 2 cases and remained stuck in the right ventricle in 1 case. Only one pacing catheter was abandoned. After an average follow-up of 45 months, none of the patients had recurrent infection or any other complication. The authors conclude that extraction of infected pacing catheters is safe and effective. It is the treatment of choice of this complication