500 research outputs found
Polarized quark distributions from semiinclusive leptoproduction
No full textSemi-inclusive deep inelastic scattering of
longitudinally polarized electrons on a polarized
proton (deuteron) target have been simulated
by means of Monte Carlo techniques for the proposed
HERMES experiment. The simulations show how HERMES
could determine the spin contribution of valence quarks
to the proton spin and reveal the existence of a negatively
polarized sea
Body weight gain after radioiodine therapy of hyperthyroidism
No full textSummary
Aim: Analysis and follow up of body weight after radioiodine therapy (RITh) of hyperthyroidism, since excessive weight gain is a common complaint among these patients. Methods: Therapy and body weight related data of 100 consecutive RITh-patients were retrospectively analysed from the time before up to three years after RITh. All patients suffered from hyperthyroidism (Graves‘ disease or autonomy), but were adjusted to euthyroid levels after RITh. Patients‘ data were compared to a control group of 48 euthyroid patients out of the same ambulance and during the same time scale. Results: All patients (RITh and controls) gained weight over the time. There was no statistically significant difference in BMI development over three years between RITh-patients and controls (5.5% resp. 4.9% increase). In the first year after RITh, weight gain of the RITh patients was higher indeed, but lower in the follow up, resulting in the same range of weight gain after three years as the controls. Besides that women showed a slightly higher increase of BMI than men, and so did younger patients compared to elder as well as patients with overweight already before RITh. Conclusions: An initially distinct increase of body weight after RITh of hyperthyroidism is mainly a compensation of pretherapeutic weight loss due to hyperthyroidism. Presupposing adequate euthyroid adjustment of thyroid metabolism after therapy, RITh is not responsible for later weight gain and adipositas.</jats:p
Nuclear medium dependence of transverse Lambda polarization in quasi-real photoproduction
No full textMeasurements of atomic recombination in the HERMES polarized hydrogen and deuterium storage cell target
No full textThe use of storage cells has become a standard technique for internal gas targets in storage rings. In case of polarized hydrogen or deuterium targets, recombination of the atoms occurs during the collisions of the atoms with the walls of the storage cell and may lead to a reduction of the target polarization. In this paper, we present measurements of recombination at the polarized internal hydrogen and deuterium gas target of the HERMES experiment in the years 1997-1999 within a temperature range of 35-250 K. The underlying reaction mechanisms will be discussed with respect to the measured temperature and gas density dependence of surface recombination. Special attention is paid to the influence of water on recombination.
These dependencies can be consistently described by a combination of three reaction mechanisms. The first one, dominating at temperatures above 120 K, is an activated Eley-Rideal reaction. A second process dominating below 100 K in case of new storage cells, is interpreted as a tunneling reaction between a physisorbed state and an atom chemically bound on the surface. When the storage cell coating is aged by the influence of the HERA positron beam, the second process is suppressed and a third (weaker) process starts to dominate. This third mechanism is described by Langmuir-Hinshelwood type reactions between physisorbed atoms
Kosten-Effektivitäts-Analyse: Radioiod oder thyreostatische Medikation bei der Primärbehandlung der Immunhyperthyreose
No full textZusammenfassung
Ziel: Die Erstmanifestation einer Immunhyperthyreose wird in Europa überwiegend thyreostatisch, in den USA mehrheitlich mit Radioiod definitiv behandelt. Diese beiden Alternativen wurden auf dem Hintergrund neuer nationaler Entlassungsrichtwerte nach einer Radioiodtherapie (RITh) verglichen. Methode: Aus Sicht der Gesellschaft entscheiden einerseits die langfristigen Rezidivraten, andererseits die Menge medizinischer Leistungen, der Versicherungsstatus und der Produktivitätsausfall des Patienten (Fehlzeiten, Einkommen) sowie die zeitliche Verteilung der Kosten (Diskontierung) über die Kosten-Effektivität. Lebenszeitbezogen wurden die medizinischen Leistungen auf 30 Patientenjahre hochgerechnet. Die Kosten der RITh basierten auf 300 Patienten, deren Entlassung bei 250 MBq lod-131-Restaktivität angenommen wurde. Ergebnis: Kosteneffektivität der konservativen Behandlung war bei einer Rezidivrate von 50% oder günstiger, bei einem Leistungsumfang gemäß den Empfehlungen der Fachgesellschaften und bei einem Zeiteinsatz des Patienten für eine ambulante Untersuchung von einem Viertel seines Arbeitstages oder kürzer zu erwarten. Sofern diese Annahmen nicht vorlagen, wurde die primäre RITh in 1593 von 1944 durchgeführten Modellrechnungen zur kosteneffektiven Entscheidung. Konservative Therapieversuche der Rezidivhyperthyreose besaßen eine stark kostenhebende Wirkung. Schlußfolgerung: Für die Patienten mit erhöhter Rezidivwahrscheinlichkeit im Falle der konservativen Behandlung (Struma, jüngeres Lebensalter, persistierend erhöhte TSH-Rezeptor-Antikörper beziehungsweise erhöhter Technetium-Uptake) bedeutet die primäre RITH eine kosteneffektive Entscheidung.</jats:p
Measurements of the nucleon structure function F on iron
No full textThe nucleon structure function F/sub 2/ has been measured by the European Muon Collaboration at four different energies using an iron scintillator target. Preliminary data are presented for beam energies of 250 and 280 GeV. (10 refs)
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