349 research outputs found

    Aspirin but not ibuprofen use is associated with reduced risk of prostate cancer: a PLCO study.

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    Background: Although most epidemiological studies suggest that non-steroidal anti-inflammatory drug use is inversely associated with prostate cancer risk, the magnitude and specificity of this association remain unclear. Methods: We examined self-reported aspirin and ibuprofen use in relation to prostate cancer risk among 29 450 men ages 55–74 who were initially screened for prostate cancer from 1993 to 2001 in the Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial. Men were followed from their first screening exam until 31 December 2009, during which 3575 cases of prostate cancer were identified. Results: After adjusting for potential confounders, the hazard ratios (HRs) of prostate cancer associated with \u3c1 and 1 pill of aspirin daily were 0.98 (95% confidence interval (CI), 0.90–1.07) and 0.92 (95% CI: 0.85–0.99), respectively, compared with never use (P for trend 0.04). The effect of taking at least one aspirin daily was more pronounced when restricting the analyses to men older than age 65 or men who had a history of cardiovascular-related diseases or arthritis (HR (95% CI); 0.87 (0.78–0.97), 0.89 (0.80–0.99), and 0.88 (0.78–1.00), respectively). The data did not support an association between ibuprofen use and prostate cancer risk. Conclusion: Daily aspirin use, but not ibuprofen use, was associated with lower risk of prostate cancer risk

    An optical fibre rereadable radiation dosimeter for use at high doses and at elevated temperature

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    A new type of radiation dosimeter for large radiation doses is described, which is based on silica fibre material. Conventional radioluminescence or thermoluminescence of silica produces emission in the blue region of the spectrum. However, in this new material irradiation, in conjunction with a heat treatment, generates a green emission band. The intensity of the green band can be monitored by either radioluminescence or thermoluminescence using a test dose. The signals are directly related to the total irradiation history of the material. The dosimeter is therefore rereadable. The production mechanism of the green emission centre requires a thermal processing stage, with an activation energy of 0.52 eV. Further, the dosimeter is effective at recording radiation during high-temperature exposure, to at least 400Β°C, with the subsequent dosimetry being performed below 200Β°C

    Equal opportunities: Do shareable interfaces promote more group participation than single users displays?

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    Computers designed for single use are often appropriated suboptimally when used by small colocated groups working together. Our research investigates whether shareable interfaces–that are designed for more than one user to inter-act with–can facilitate more equitable participation in colocated group settings compared with single user displays. We present a conceptual framework that characterizes Shared Information Spaces (SISs) in terms of how they constrain and invite participation using different entry points. An experiment was conducted that compared three different SISs: a physical-digital set-up (least constrained), a multitouch tabletop (medium), and a laptop display (most constrained). Statistical analyses showed there to be little difference in participation levels between the three conditions other than a predictable lack of equity of control over the interface in the laptop condition. However, detailed qualitative analyses revealed more equitable participation took place in the physical-digital condition in terms of verbal utterances over time. Those who spoke the least contributed most to the physical design task. The findings are discussed in relation to the conceptual framework and, more generally, in terms of how to select, design, and combine different display technologies to support collaborative activities

    Towards an approach for analysing external representations created during sensemaking using generative grammar

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    During sensemaking, users often create external representations to help them make sense of what they know, and what they need to know. In doing so, they necessarily adopt or construct some form of representational language using the tools at hand. By describing such languages implicit in representations we believe that we are better able to describe and differentiate what users do and better able to describe and differentiate interfaces that might support them. Drawing on approaches to the analysis of language, and in particular, Mann and Thompson’s Rhetorical Structure Theory, we analyse the representations that users create to expose their underlying β€˜visual grammar’. We do this in the context of a user study involving evidential reasoning. Participants were asked to address an adapted version of IEEE VAST 2011 mini challenge 3 (interpret a potential terrorist plot implicit in a set of news reports). We show how our approach enables the unpacking of the heterogeneous and embedded nature of user-generated representations and allows us to show how visual grammars evolve and become more complex over time in response to evolving sensemaking needs

    Modeling of dielectric hysteresis loops in ferroelectric semiconductors with charged defects

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    We have proposed the phenomenological description of dielectric hysteresis loops in ferroelectric semiconductors with charged defects and prevailing extrinsic conductivity. Exactly we have modified Landau-Ginsburg approach and shown that the macroscopic state of the aforementioned inhomogeneous system can be described by three coupled equations for three order parameters. Both the experimentally observed coercive field values well below the thermodynamic one and the various hysteresis loop deformations (constricted and double loops) have been obtained in the framework of our model. The obtained results quantitatively explain the ferroelectric switching in such ferroelectric materials as thick PZT films.Comment: 21 pages, 10 figures, sent to Journal of Physics: Condensed Matte

    Probing the Interstellar Medium in Early type galaxies with ISO observations

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    Four IRAS-detected early type galaxies were observed with ISO. With the exception of the 15 micron image of NGC1052, the mid-IR emission from NGC1052, NGC1155, NGC5866 and NGC6958 at 4.5, 7 and 15 microns show extended emission. Mid-IR emission from NGC1052, NGC1155, and NGC6958 follows a de Vaucouleurs profile. The ratio of 15/7 micron flux decreases with radius in these galaxies, approaching the values empirically observed for purely stellar systems. In NGC5866, the 7 and 15 micron emission is concentrated in the edge-on dust lane. All the galaxies are detected in the [CII] line, and the S0s NGC1155 and NGC5866 are detected in the [OI] line as well. The ISO-LWS observations of the [CII] line are more sensitive measures of cool, neutral ISM than HI and CO by about a factor of 10-100. Three of four early type galaxies, namely NGC1052, NGC6958 and NGC5866, have low ratio FIR/Blue and show a lower [CII]/FIR, which is due to a softer radiation field from old stellar populations. The low [CII]/CO ratio in NGC5866 ([CII]/CO(1-0) < 570) confirms this scenario. We estimate the UV radiation expected from the old stellar populations in these galaxies and compare it to that needed to heat the gas to account for the cooling observed [CII] and [OI] lines. In three out of four galaxies, NGC1052, NGC5866 and NGC6958, the predicted UV radiation falls short by a factor of 2-3. In view of the observed intrinsic scatter in the "UV-upturn" in elliptical galaxies and its great sensitivity to age and metallicity effects, this is not significant. However, the much larger difference (about a factor of 20) between the UV radiation from old stars and that needed to produce the FIR lines for NGC 1155 is strong evidence for the presence of young stars, in NGC1155.Comment: To appear in the Astrophysical Journal. Figure 1 appears as a separate jpg figur

    Adult weight change and premenopausal breast cancer risk: A prospective pooled analysis of data from 628,463 women.

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    Early-adulthood body size is strongly inversely associated with risk of premenopausal breast cancer. It is unclear whether subsequent changes in weight affect risk. We pooled individual-level data from 17 prospective studies to investigate the association of weight change with premenopausal breast cancer risk, considering strata of initial weight, timing of weight change, other breast cancer risk factors and breast cancer subtype. Hazard ratios (HR) and 95% confidence intervals (CI) were obtained using Cox regression. Among 628,463 women, 10,886 were diagnosed with breast cancer before menopause. Models adjusted for initial weight at ages 18-24 years and other breast cancer risk factors showed that weight gain from ages 18-24 to 35-44 or to 45-54 years was inversely associated with breast cancer overall (e.g., HR per 5 kg to ages 45-54: 0.96, 95% CI: 0.95-0.98) and with oestrogen-receptor(ER)-positive breast cancer (HR per 5 kg to ages 45-54: 0.96, 95% CI: 0.94-0.98). Weight gain from ages 25-34 was inversely associated with ER-positive breast cancer only and weight gain from ages 35-44 was not associated with risk. None of these weight gains were associated with ER-negative breast cancer. Weight loss was not consistently associated with overall or ER-specific risk after adjusting for initial weight. Weight increase from early-adulthood to ages 45-54 years is associated with a reduced premenopausal breast cancer risk independently of early-adulthood weight. Biological explanations are needed to account for these two separate factors

    Dynamical Evolution of Planetary Systems

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    Planetary systems can evolve dynamically even after the full growth of the planets themselves. There is actually circumstantial evidence that most planetary systems become unstable after the disappearance of gas from the protoplanetary disk. These instabilities can be due to the original system being too crowded and too closely packed or to external perturbations such as tides, planetesimal scattering, or torques from distant stellar companions. The Solar System was not exceptional in this sense. In its inner part, a crowded system of planetary embryos became unstable, leading to a series of mutual impacts that built the terrestrial planets on a timescale of ~100 My. In its outer part, the giant planets became temporarily unstable and their orbital configuration expanded under the effect of mutual encounters. A planet might have been ejected in this phase. Thus, the orbital distributions of planetary systems that we observe today, both solar and extrasolar ones, can be different from the those emerging from the formation process and it is important to consider possible long-term evolutionary effects to connect the two.Comment: Review to appear as a chapter in the "Handbook of Exoplanets", ed. H. Deeg & J.A. Belmont
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