7,815 research outputs found

    The Detection of a 3.5-h Period in the Classical Nova Velorum 1999 (V382 Vel) and the Long Term Behavior of the Nova Light Curve

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    We present CCD photometry, light curve and time series analysis of the classical nova V382 Vel (N Vel 1999). The source was observed for 2 nights in 2000, 21 nights in 2001 and 7 nights in 2002 using clear filters. We report the detection of a distinct period in the light curve of the nova P=0.146126(18) d (3.5 h). The period is evident in all data sets, and we interpret it as the binary period of the system. We also measured an increase in the amplitude modulation of the optical light (in magnitude) by more than 55% from 2000 to 2001 and about 64% from 2001 to 2002. The pulse profiles in 2001 show deviations from a pure sinusoidal shape which progressively become more sinusoidal by 2002. The main cause of the variations in 2001 and 2002 can be explained with the occultation of the accretion disk by the secondary star. We interpret the observed deviations from a pure sinusoidal shape as additional flux resulting from the aspect variations of the irradiated face of the secondary star.Comment: 16 pages and 4 figures, accepted as it stands to be published in the Astronomical Journal (AJ

    Wess-Zumino-Witten model off criticality

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    We study the renormalization group flow properties of the Wess-Zumino-Witten model in the region of couplings between g2=0g^2=0 and g2=4Ï€/kg^2=4\pi/k, by evaluating the two-loop Zamolodchikov's cc-function. We also discuss the region of negative couplings.Comment: 8 page

    The effect of three years of TNF alpha blocking therapy on markers of bone turnover and their predictive value for treatment discontinuation in patients with ankylosing spondylitis: a prospective longitudinal observational cohort study

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    INTRODUCTION: The aim of this study was to investigate the effect of three years of tumor necrosis factor-alpha (TNF-alpha) blocking therapy on bone turnover as well as to analyze the predictive value of early changes in bone turnover markers (BTM) for treatment discontinuation in patients with ankylosing spondylitis (AS). METHODS: This is a prospective cohort study of 111 consecutive AS outpatients who started TNF-alpha blocking therapy. Clinical assessments and BTM were assessed at baseline, three and six months, as well as at one, two, and three years. Z-scores of BTM were calculated to correct for age and gender. Bone mineral density (BMD) was assessed yearly. RESULTS: After three years, 72 patients (65%) were still using their first TNF-alpha blocking agent. In these patients, TNF-alpha blocking therapy resulted in significantly increased bone-specific alkaline phosphatase, a marker of bone formation; decreased serum collagen-telopeptide (sCTX), a marker of bone resorption; and increased lumbar spine and hip BMD compared to baseline. Baseline to three months decrease in sCTX Z-score (HR: 0.394, 95% CI: 0.263 to 0.591), AS disease activity score (ASDAS; HR: 0.488, 95% CI: 0.317 to 0.752), and physician's global disease activity (HR: 0.739, 95% CI: 0.600 to 0.909) were independent inversely related predictors of time to treatment discontinuation because of inefficacy or intolerance. Early decrease in sCTX Z-score correlated significantly with good long-term response regarding disease activity, physical function and quality of life. CONCLUSIONS: Three years of TNF-alpha blocking therapy results in a bone turnover balance that favors bone formation, especially mineralization, in combination with continuous improvement of lumbar spine BMD. Early change in sCTX can serve as an objective measure in the evaluation of TNF-alpha blocking therapy in AS, in addition to the currently used more subjective measures

    Broilers with Taste - Sustainable chicken takes flight

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    Engelse versie van de brochure 'Pluimvee met smaak : duurzame kip krijgt vleugels', die laat zien waar kansen liggen voor de Nederlandse pluimveesector om te verduurzamen. Twee uiteenlopende concepten, de Som der Delen en de Windstreek, geven ieder op eigen wijze invulling aan duurzaamheid op het primaire bedrijf. Ze bevatten belangrijke elementen voor verduurzaming, die als geheel of in onderdelen, nu of later, in de praktijk gebracht kunnen worden. Duurzaamheid kent immers niet één, maar vele vormen, afhankelijk van de ondernemers, de markt en de omgeving

    On the identity of broad-shelled mussels (Mollusca, Bivalvia, Mytilus) from the Dutch delta region

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    Late Quaternary (Eemian) deposits of the Netherlands contain shells that resemble those of living Mytilus galloprovincialis. Similar broad-shelled mytilids also occur in estuaries of the southwestern Netherlands together with slender individuals typical of M. edulis. We sampled living mussels along a depth gradient in the Oosterschelde to a) investigate whether a relation exists between shell shape and depth, b) test if the broadshelled specimens might represent M. galloprovincialis (or a hybrid with M. edulis) and c) assess by inference if the Quaternary specimens might be attributed to M. galloprovincialis as well. In order to do so, we compared genetic (length polymorphism of Me 15/16, COIII sequences and AFLPs) and shellmorphological characteristics (juvenile L/W ratios and socalled Verduin parameters) of the same specimens. The obtained dataset indicates that all studied mussels from the Oosterschelde should be attributed to M. edulis, including those with broad shell outlines. No correlation of shell-morphology and depth-distribution was found. The worn and generally damaged state of the Eemian specimens precluded measurement of the Verduin parameters, while juvenile L/W ratios turned out not to be diagnostic. Therefore the shell characters examined in this study are insufficient to demonstrate the possible presence of M. galloprovincialis shells in Quaternary deposits of the Netherlands.

    Decuplet baryon magnetic moments in a QCD-based quark model beyond quenched approximation

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    We study the decuplet baryon magnetic moments in a QCD-based quark model beyond quenched approximation. Our approach for unquenching the theory is based on the heavy baryon perturbation theory in which the axial couplings for baryon - meson and the meson-meson-photon couplings from the chiral perturbation theory are used together with the QM moment couplings. It also involves the introduction of a form factor characterizing the structure of baryons considered as composite particles. Using the parameters obtained from fitting the octet baryon magnetic moments, we predict the decuplet baryon magnetic moments. The Ω−\Omega^- magnetic moment is found to be in good agreement with experiment: μΩ−\mu_{\Omega^-} is predicted to be −1.97μN-1.97 \mu_N compared to the experimental result of (−-2.02 ±\pm 0.05) μN\mu_N.Comment: 19 pages, 2 figure

    Ferromagnetism below 10 K in Mn doped BiTe

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    Ferromagnetism is observed below 10 K in [Bi0.75Te0.125Mn0.125]Te. This material has the BiTe structure, which is made from the stacking of two Te-Bi-Te-Bi-Te blocks and one Bi-Bi block per unit cell. Crystal structure analysis shows that Mn is localized in the Bi2 blocks, and is accompanied by an equal amount of TeBi anti-site occupancy in the Bi2Te3 blocks. These TeBi anti-site defects greatly enhance the Mn solubility. This is demonstrated by comparison of the [Bi1-xMnx]Te and [Bi1-2xTexMnx]Te series; in the former, the solubility is limited to x = 0.067, while the latter has xmax = 0.125. The magnetism in [Bi1-xMnx]Te changes little with x, while that for [Bi1-2xTexMnx]Te shows a clear variation, leading to ferromagnetism for x > 0.067. Magnetic hysteresis and the anomalous Hall Effect are observed for the ferromagnetic samples.Comment: Accepted for publication in Phys. Rev.

    Feasibility of a dose-intensive CMF regimen with granulocyte colony-stimulating factor as adjuvant therapy in premenopausal patients with node-positive breast cancer

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    Our aim was to study the feasibility of an intensified intravenous CMF (cyclophosphamide, methotrexate and 5-fluorouracil) schedule with the aim to escalate dose intensity (DI). Twenty-three premenopausal breast cancer patients received 6 cycles of adjuvant CMF intravenously on days 1 and 8 every 3 weeks and granulocyte colony-stimulating factor days 9–18. Endpoints were DI and toxicity. Twenty-one out of 23 patients (91%) received the projected total dose and reached ≥ 85% of the projected DI. Compared to ‘classical’ CMF, all patients reached ≥ 111% DI. Nine patients received the planned schedule without delay. Thirteen patients (57%) were treated for infection and four patients (17%) were hospitalized for febrile neutropenia. Twelve patients received red blood cell transfusions (52%). Radiation therapy (n= 6) had no adverse impact on dose intensity or haematological toxicity. This dose-intensified CMF schedule was accompanied by enhanced haematological toxicity with clinical sequelae, namely fever, intravenous antibiotics and red blood cell transfusions, but allows a high dose intensity in a majority of patients. © 2000 Cancer Research Campaig
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