The atmospheric neutrino flavour ratio measured using a 1.52 kton-year exposure of Soudan 2 is found to be 0.72 ± 0.19
−0.07
+0.05 relative to the expected value from a Monte Carlo calculation. The ...possible background of interactions of neutrons and photons produced in muon interactions in the rock surrounding the detector has been investigated and is shown not to produce low values of the ratio.
BACKGROUND: Although the role of vitamin D deficiency in causing osteomalacia is well recognised, there is limited evidence to suggest that vitamin D deficiency is associated with osteoporosis. One ...community based study has suggested a reduction in bone density in females with low vitamin D levels, while another has shown no effect of isolated vitamin D deficiency on population fracture rates. We aimed to assess bone density in a cohort of women with low vitamin D levels but no other identified risk factors for osteoporosis. We wished to see if there was any relationship between the two, in order to clarify whether measurement of vitamin D was justified in aiding selection of patients for DXA, and whether DXA was justified in patients found to have isolated vitamin D deficiency. METHODS: We identified 70 women referred to an open access DXA scanning service by their GP with low vitamin D levels (under 48 nmol/l) as their only risk factor. We performed DXA of hip and spine and recorded the absolute bone density and Z scores for each patient, together with their vitamin D levels. We calculated the mean (SD) values for Z score at hip and spine, and compared these to a control group of women referred for baseline DXA prior to commencing aromatase inhibitors for breast cancer. We also compared the results with those obtained from the rest of the GP database for women referred up with a 10 year risk of osteoporotic fractures calculated at over 10% using FRAX. These statistical comparisons were made using unpaired Students t test. Mean values for Z scores at hip and spine were calculated and compared within the index group for those with vitamin D levels above and below 20 nmol/l using Students t test. Correlation coefficients between vitamin D levels and Z scores at hip and spine were also calculated for the index group. RESULTS: Mean (SD) values for Z scores in the hip and spine for patients with isolated vitamin D deficiency were +0.30 (0.87) and +0.46 (0.92) respectively. These were not significantly different from controls whose corresponding values were +0.17 (0.34) and +0.49 (0.45). By contrast, patients with a 10 year risk of fracture of over 10% had lower values at hip -0.01 (0.07) and spine -0.13 (0.09) p = 0.01. Mean Z scores for those with very low vitamin D levels (under 20 nmol/l) were not significantly different at either site when compared to those with less severe deficiency (20-48 nmol/l) p = 0.26. There was no correlation between vitamin D levels and Z scores at hip or spine r = 0.01 CONCLUSIONS: There was no overall decrease in bone density associated with low vitamin D levels in women in our study. There is no evidence to support the routine measurement of vitamin D to select patients for DXA scanning. There is no reason to perform DXA scans in those patients who have an isolated vitamin D deficiency in the absence of defined risk factors for osteoporosis. Disclosure statement: The authors have declared no conflicts of interest.
We present results from an analysis of B(0)B(0)--> rho(+)rho(-) using 232 x 10(6) Gamma (4S) --> BB decays collected with the BABAR detector at the PEP-II asymmetric-energy B factory at SLAC. We ...measure the longitudinal polarization fraction f(L) = 0.978 +/- 0.014(stat) + 0.021 / -0.029(syst) and the CP-violating parameters S(L)= -0.33 +/- 0.24(stat) + 0.08 / -0.14(syst) and C(L)= -0.03 +/- 0.18(stat) +/- 0.09(syst). Using an isospin analysis of B --> rhorho decays, we determine the unitarity triangle parameter alpha. The solution compatible with the standard model is alpha = (100 +/- 13) degrees.
(Note: This consensus statement appeared in somewhat differing
format as an editorial in the Western Journal of Medicine
2001;175 October 2001. The full text and list of
cosigners is published here ...for the first time.) Bioethics is the formal discipline concerned with ethical and
broader issues arising in the practice of medicine and the other
healthcare professions and science as a whole. Bioethicists are
concerned not only with the impacts and quandaries faced by
individual patients and their caregivers, but the impacts of
healthcare on society and the broader natural world. Although
bioethicists approach such issues from many different theoretical
perspectives, most if not all agree that the healthcare professions
and industry should seek to minimize any real or potential health
risks associated with providing healthcare.
We report measurements of branching fractions and charge asymmetries of exclusive decays of neutral and charged B mesons into two-body final states containing a charmonium state and a light strange ...meson. The charmonium mesons considered are J/psi, psi(2S) and chi(c1), and the light meson is either K or K(*). We use a sample of about 124x10(6) BB pairs collected with the BABAR detector at the PEP-II storage ring at the Stanford Linear Accelerator Center.
This study assesses the performance of the Geostationary Ocean Imager (GOCI) for mapping of suspended paniculate matter in the Bohai Sea, a turbid water region. GOCI imagery for remote sensing ...reflectance and Total Suspended Solids (TSS) is analysed in detail for two days in June 2011 (8 images per day). Both instantaneous and daily composite maps are considered and a comparison is made with corresponding reflectance and TSS products from MODIS-AQUA. Results show TSS distributions corresponding to previous studies of the region. The advantage of the higher acquisition frequency (8 images/day instead of 1) offered by GOCI is clearly demonstrated in the daily composite which is more complete during this period of scattered but moving clouds. Consideration of temporal variation over the day indicates low natural variability but some artificial variability from processing errors - this analysis provides a first indication of how the higher frequency of data from geostationary ocean colour could lead to improved data quality control via temporal coherency outlier detection. While there is room for improvement on the GOCI calibration, atmospheric correction and retrieval algorithms, the current study suggests that the GOCI data can already be used now to study qualitatively sediment dynamics except in the extremely turbid waters which are masked out of the current dataset. In a wider context, it is considered that the technical challenges of geostationary ocean colour have been met by the GOCI concept, and, notwithstanding potential improvements on the concept and data processing methods, it is recommended that this mission serve as a model for future geostationary ocean colour sensors over Europe/Africa and the Americas.
Spontaneous light emission from fibers in MINOS Avvakumov, S.; Barrett, W.L.; Belias, T. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
06/2005, Letnik:
545, Številka:
1
Journal Article
Recenzirano
We report on the observation and measurements of unexpected background rates in the MINOS Far Detector. The noise level at the Far Detector is significantly greater than that expected from natural ...radioactivity and intrinsic photomultiplier dark current. We have conducted a series of additional tests which demonstrate that the excess rate is caused by spontaneous light emission in the wavelength-shifting fibers, which are used to read out signals from scintillator strips. This noise due to fibers exhibits an exponential fall off with time with a decay time constant of the order of 100 days.
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