Timing and risk factors for clinical fractures among postmenopausal women: a 5-year prospective study

BACKGROUND: Many risk factors for fractures have been documented, including low bone-mineral density (BMD) and a history of fractures. However, little is known about the short-term absolute risk (AR) of fractures and the timing of clinical fractures. Therefore, we assessed the risk and timing of incident clinical fractures, expressed as 5-year AR, in postmenopausal women. METHODS: In total, 10 general practice centres participated in this population-based prospective study. Five years after a baseline assessment, which included clinical risk factor evaluation and BMD measurement, 759 postmenopausal women aged between 50 and 80 years, were re-examined, including undergoing an evaluation of clinical fractures after menopause. Risk factors for incident fractures at baseline that were significant in univariate analyses were included in a multivariate Cox survival regression analysis. The significant determinants were used to construct algorithms. RESULTS: In the total group, 12.5% (95% confidence interval (CI) 10.1–14.9) of the women experienced a new clinical fracture. A previous clinical fracture after menopause and a low BMD (T-score <-1.0) were retained as significant predictors with significant interaction. Women with a recent previous fracture (during the past 5 years) had an AR of 50.1% (95% CI 42.0–58.1) versus 21.2% (95% CI 20.7–21.6) if the previous fracture had occurred earlier. In women without a fracture history, the AR was 13.8% (95% CI 10.9–16.6) if BMD was low and 7.0% (95% CI 5.5–8.5) if BMD was normal. CONCLUSION: In postmenopausal women, clinical fractures cluster in time. One in two women with a recent clinical fracture had a new clinical fracture within 5 years, regardless of BMD. The 5-year AR for a first clinical fracture was much lower and depended on BMD

IMAGE CONSTRUCTION FROM THE IRAS SURVEY

IRAS survery data can be used successfully to produce images of extended objects. The major difficulties, viz. non-uniform sampling, different response functions for each detector, and varying signal-to-noise levels for each detector for each scan, have been resolved. The results of three different image construction techniques are compared: co-addition, constrained least-squares, and maximum entropy. The maximum entropy result is superior. We present an image of the galaxy M51 with an average spatial resolution of 45 arc seconds, using 60-mu-m survey data. This exceeds the telescope diffraction limit of about 1 minute of arc at this wavelength

Cool dust and gas in the Small Magellanic Cloud

We present high-angular-resolution, far-infrared images of the Small Magellanic Cloud (SMC). The images were reconstructed from data obtained with the Infrared Astronomical Satellite (IRAS), using the Pyramid Maximum Entropy algorithm. The angular resolutions of the images are 1 arcmin at 12, 25 and 60 mu m, and 1.7 arcmin at 100 mu m, which provides an excellent complement to the recent neutral hydrogen (H I) survey from the Australia Telescope Compact Array, which has a resolution of 1.6 arcmin. We use the 60- and 100-mu m data, together with a standard dust model, to derive a temperature map and a dust column density distribution. Dust temperatures range from 23 to 45 K, which is, on average, warmer than for the Galaxy, although there is a deficit of warm, very small dust grains in the SMC. The total amount of cool dust in the SMC is 1.8(-0.2)(+1.3) x 10(4) M.. There is a significant variation of the observed dust-to-gas ratio across the SMC. This may be caused by corresponding variations in metallicity, but this explanation is not supported by the limited available data in the literature. Alternatively, there may be a large amount of molecular hydrogen (H(2)) in the SMC, similar to 8 x 10(8) M., and/or a large amount (similar to 10(6) M.) of cold dust (less than or equal to 15 K) not seen by IRAS or COBE/DIRBE. The average dust-to-atomic gas ratio is, by mass, 8.2 x 10(-5), which is a factor of similar to 30 below the Galactic value. The spatial power spectrum of the dust column density image can be approximated by P(d)(k) proportional to k(-3.1), which shows that, as with the H I power spectrum, there is no preferred scale size for dust clouds. A spatial coherence analysis shows that, over a wide range of spatial scales (greater than or similar to 50 pc), H I and dust are well correlated (> 60 per cent)

Observing with the ISO Short-Wavelength Spectrometer.

The Short-Wavelength Spectrometer (SWS) is one of the four instruments on-board ESA's Infrared Space Observatory (ISO), launched on November 17, 1995. The spectrometer covers the wavelength range of 2.38 to 45.2 μm with a spectral resolution ranging from 1000 to 2000. By inserting Fabry-Perot filters the resolution can be enhanced by a factor 20 for the wavelength range from 11.4 to 44.5 μm. An overview is given of the instrument, its in-orbit calibration, performance, observing modes and off-line processing software.keywords: INSTRUMENTATION: SPECTROGRAPHS, METHODS: DATA ANALYSIS, METHODS: OBSERVATIONAL, TECHNIQUES: SPECTROSCOPIC, INFRARED: GENERAL adsurl: https://ui.adsabs.harvard.edu/#abs/1996A&A...315L..49D adsnote: Provided by the SAO/NASA Astrophysics Data Systemstatus: publishe