404 research outputs found

    Hyperhomocysteinaemia is associated with coronary events in type 2 diabetes

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    Objectives. Amongst nondiabetic individuals, a high serum homocysteine concentration is an independent but relatively weak risk factor for coronary events. However, it is not known whether homocysteine increases risk of coronary events in type 2 diabetes. Therefore, we examined the combined effect of homocysteine and type 2 diabetes on risk of fatal and nonfatal coronary events. Subjects. We assessed the 10-year risk of coronary events associated with homocysteine amongst diabetic (n = 140) and nondiabetic (n = 361) individuals. Design. We did this in the Hoorn Study, a population-based study of glucose tolerance and related complications in Caucasian men and women aged 50-75 years. Results. The incidence rate for coronary events was 2.63 (29 of 140) per 100 person-years amongst diabetic and 1.29 (42 of 361) amongst nondiabetic individuals. Amongst diabetic individuals, risk of coronary events increased 28% for each 5-μmol

    CP violation at colliders

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    The prospects of experimental detection of CPCP violation at e+ee^+e^- and pp/pppp/p\overline{p} colliders are reviewed. After a general discussion on the quantities which can measure CPCP violation and on the implications of the CPTCPT theorem, various possibilities of measuring CPCP violation arising outside the standard model are taken up. CPCP violation in leptonic processes, especially polarization effects in e+el+le^+e^-\rightarrow l^+l^- are discussed next. CPCP violation in ttt\overline{t} and W+WW^+W^- production and decay is also described. (Based on talk presented at the WHEPP3, Madras, January 1994).Comment: 20 pages, latex, no figures (only revision is the comment that the article is based on a talk presented at WHEPP3, Madras, January 1994

    Pure spinor computation towards open string three-loop

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    Using the recent results in the pure spinor formulation, we lay out a ground-work towards the full momentum space amplitudes of open superstrings at three-loop. After briefly reviewing the one-loop amplitude, we directly work out the two-loop and reproduce the result that was obtained by a symmetry argument. For the three-loop, first we use the two-loop regulator as a warm-up exercise. The result vanishes. We then employ the regulator that has been recently proposed by Aisaka and Berkovits (AB). It is noted that the terms in higher power in 1λλˉ\frac{1}{\lambda\bar{\lambda}} that render the two-loop regulator disqualified for the three-loop do not contribute. This with a few other indications suggests a possibility that the AB regulator might also lead to a vanishing result. Nevertheless, we argue that it is possible to acquire the three-loop amplitude, and present a result that we anticipate to be the three-loop amplitude.Comment: 41 pages, latex, cosmetic change

    Weak dipole moment of τ\tau in e+ee^+e^- collisions with longitudinally polarized electrons

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    It is pointed out that certain CP-odd momentum correlations in the production and subsequent decay of tau pairs in e+ee^+e^- collisions get enhanced when the ee^- is longitudinally polarized. Analytic expressions for these correlations are obtained for the single-pion decay mode of τ\tau when τ+τ\tau^+\tau^- have a ``weak" dipole form factor (WDFF) coupling to ZZ . For e+ee^+e^- collisions at the ZZ peak, a sensitivity of about 1-5×1017\times 10^{-17}\mbox{ee cm} for the τ\tau WDFF can be reached using a {\em single} τ+τ\tau^+\tau^- decay channel, with 106Z10^6\, Z's likely to be available at the SLC at Stanford with ee^- polarization of 62\%-75\%.Comment: 9 pages, Latex, PRL-TH-93/17 (Revised

    Measurement of the τ\tau electric dipole moment using longitudinal polarization of e+ee^+e^- beams

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    Certain CP-odd momentum correlations in the production and subsequent decay of τ\tau pairs in e+ee^+ e^- collisions are enhanced significantly when the e+e^+ and ee^- beams are longitudinally polarized. These may be used to probe the real and imaginary parts of dτγd_\tau^\gamma, the electric dipole moment of the τ\tau. Closed-form expressions for these ``vector correlations'' and the standard deviation of the operators defining them due to standard model interactions are presented for the two-body final states of τ\tau decays. If 42\% average polarization of each beam is achieved, as proposed for the tau-charm factories, with equal integrated luminosities for each sign of polarization and a total yield of 21072\cdot 10^7 τ+τ\tau^+ \tau^- pairs, it is possible to attain sensitivities for δRedτγ\vert\delta {\rm Re} d_{\tau}^{\gamma}\vert of 810198\cdot 10^{-19}, 110191\cdot 10^{-19}, 110191\cdot 10^{-19} ee cm respectively and for δImdτγ\vert\delta {\rm Im} d_{\tau}^{\gamma}\vert of 410144\cdot 10^{-14}, 610156\cdot 10^{-15}, 510165\cdot 10^{-16} ee cm respectively at the three operating center-of-mass energies of 3.67, 4.25 and 10.58 GeV. These bounds emerge when the effects of a posible weak dipole form factor dτZd_\tau^Z are negligible as is the case when it is of the same order of magnitude as dτγd_\tau^\gamma. Furthermore, in such a polarization experiment where different polarizations are possible, a model-independent disentangling of their individual effects is possible, and a technique to achieve this is described. A strong longitudinal polarization physics programme at the tau-charm factory appears warranted.Comment: 30 pages, latex, no figure

    Pure Spinor Approach to Type IIA Superstring Sigma Models and Free Differential Algebras

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    This paper considers the Free Differential Algebra and rheonomic parametrization of type IIA Supergravity, extended to include the BRS differential and the ghosts. We consider not only the ghosts lambda's of supersymmetry but also the ghosts corresponding to gauge and Lorentz transformations. In this way we can derive not only the BRS transformations of fields and ghosts but also the standard pure spinor constraints on lambda's. Moreover the formalism allows to derive the action for the pure spinor formulation of type IIA superstrings in a general background, recovering the action first obtained by Berkovits and Howe.Comment: 1+23 pages, v2: added clarifications and a reference, misprints corrected, v3: presentation improved, results unchange

    From ozone monitoring instrument (OMI) to tropospheric monitoring instrument (TROPOMI)

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    The OMI instrument is an ultraviolet-visible imaging spectrograph that uses two-dimensional CCD detectors to register both the spectrum and the swath perpendicular to the flight direction with a 115° wide swath, which enables global daily ground coverage with high spatial resolution. This paper presents a selection of in-flight radiometric and CCD detector calibration and performance monitoring results since the launch in July 2004. From these examples it will be shown that OMI is performing very well after more than four years in orbit. It is shown how the OMI irradiance measurement data have been used to derive a high resolution solar reference spectrum with good radiometric calibration, good wavelength calibration and high spectral sampling. The surface reflectance climatology derived from three years of in-orbit OMI measurement data is presented and discussed. The OMI mission may possibly be extended in 2009 for another two or four years, depending on the performance of the instrument. By 2013-2014 OMI on EOS-Aura and SCIAMACHY on ENVISAT will have reached more that twice their anticipated lifetimes. In order to guarantee continuity of Earth atmosphere tropospheric and climate measurement data new instrumentation shall be available around that time. A successor of OMI and SCIAMACHY, named TROPOspheric Monitoring Instrument (TROPOMI), scheduled for launch by the end of 2013, is discussed in this paper

    Magnetic Resonance Imaging-targeted Prostate Biopsy Compared with Systematic Prostate Biopsy in Biopsy-naïve Patients with Suspected Prostate Cancer

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    BACKGROUND: It remains uncertain whether transrectal ultrasound (TRUS)-guided systematic biopsies can be omitted and rely solely on multiparametric magnetic resonance imaging–targeted biopsies (MRI-TBx) in biopsy-naïve men suspected of prostate cancer (PCa). OBJECTIVE: To compare PCa detection in biopsy-naïve men between systematic biopsy and MRI-TBx. DESIGN, SETTING, AND PARTICIPANTS: A prospective cohort study was conducted in a Dutch teaching hospital. Consecutive patients with suspected PCa, no history of biopsy, and no clinical suspicion of metastasis underwent both TRUS-guided systematic biopsies and MRI-TBx by multiparametric magnetic resonance imaging (mpMRI)-ultrasound fusion, including sham biopsies in case of negative mpMRI. OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS: Clinically significant PCa (csPCa), defined as group ≥2 on the International Society of Urological Pathology grading, was detected. RESULTS AND LIMITATIONS: The overall prevalence of csPCa, irrespective of biopsy technique, was 37.4% (132/353) in our population. MRI-TBx were performed in 263/353 (74.5%) patients with suspicious mpMRI (Prostate Imaging Reporting and Data System [PI-RADS] ≥3). The detection rates for csPCa were 39.5% for MRI-TBx and 42.9% for systematic biopsies. The added values, defined as the additional percentages of patients with csPCa detected by adding one biopsy technique, were 8.7% for the systematic biopsies and 5.3% for MRI-TBx. In patients with nonsuspicious mpMRI, five cases (6%) of csPCa were found by systematic biopsies. CONCLUSIONS: This study in biopsy-naïve patients suspected for PCa showed that systematic biopsies have added value to MRI-TBx alone in patients with mpMRI PI-RADS >2. PATIENT SUMMARY: We studied magnetic resonance imaging (MRI)-guided prostate biopsy for diagnosing prostate cancer and compared it with the standard method of prostate biopsy. Standard systematic biopsies cannot be omitted in patients with suspicious MRI, as they add to the detection of significant prostate cancer
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