21 research outputs found

    High-resolution and low-background 163^{163}Ho spectrum: interpretation of the resonance tails

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    The determination of the effective electron neutrino mass via kinematic analysis of beta and electron capture spectra is considered to be model-independent since it relies on energy and momentum conservation. At the same time the precise description of the expected spectrum goes beyond the simple phase space term. In particular for electron capture processes, many-body electron-electron interactions lead to additional structures besides the main resonances in calorimetrically measured spectra. A precise description of the 163^{163}Ho spectrum is fundamental for understanding the impact of low intensity structures at the endpoint region where a finite neutrino mass affects the shape most strongly. We present a low-background and high-energy resolution measurement of the 163^{163}Ho spectrum obtained in the framework of the ECHo experiment. We study the line shape of the main resonances and multiplets with intensities spanning three orders of magnitude. We discuss the need to introduce an asymmetric line shape contribution due to Auger–Meitner decay of states above the auto-ionisation threshold. With this we determine an enhancement of count rate at the endpoint region of about a factor of 2, which in turn leads to an equal reduction in the required exposure of the experiment to achieve a given sensitivity on the effective electron neutrino mass

    The electron capture in 163^{163}Ho experiment – ECHo

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    Neutrinos, and in particular their tiny but non-vanishing masses, can be considered one of the doors towards physics beyond the Standard Model. Precision measurements of the kinematics of weak interactions, in particular of the 3^{3}H β-decay and the 163^{163}Ho electron capture (EC), represent the only model independent approach to determine the absolute scale of neutrino masses. The electron capture in 163^{163}Ho experiment, ECHo, is designed to reach sub-eV sensitivity on the electron neutrino mass by means of the analysis of the calorimetrically measured electron capture spectrum of the nuclide 163^{163}Ho. The maximum energy available for this decay, about 2.8 keV, constrains the type of detectors that can be used. Arrays of low temperature metallic magnetic calorimeters (MMCs) are being developed to measure the 163^{163}Ho EC spectrum with energy resolution below 3 eV FWHM and with a time resolution below 1 μs. To achieve the sub-eV sensitivity on the electron neutrino mass, together with the detector optimization, the availability of large ultra-pure 163^{163}Ho samples, the identification and suppression of background sources as well as the precise parametrization of the 163^{163}Ho EC spectrum are of utmost importance. The high-energy resolution 163^{163}Ho spectra measured with the first MMC prototypes with ion-implanted 163^{163}Ho set the basis for the ECHo experiment. We describe the conceptual design of ECHo and motivate the strategies we have adopted to carry on the present medium scale experiment, ECHo-1K. In this experiment, the use of 1 kBq 163^{163}Ho will allow to reach a neutrino mass sensitivity below 10 eV/c2^{2}. We then discuss how the results being achieved in ECHo-1k will guide the design of the next stage of the ECHo experiment, ECHo-1M, where a source of the order of 1 MBq 163^{163}Ho embedded in large MMCs arrays will allow to reach sub-eV sensitivity on the electron neutrino mass

    The electron capture in 163Ho experiment – ECHo

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    Talking matters: Abused women's views on disclosure of partner abuse to the family doctor and its role in handling the abuse situation

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    Objective: We aimed to explore what women valued most in disclosing partner abuse to their doctor and whether disclosure played a role in handling their abuse situation. Methods: A qualitative method was used to understand abused women's views and experiences with disclosure to their family doctor. Thirty-six women were interviewed within 4 weeks after disclosure to their family doctor. Results: Most women went to see the doctor for some medical complaint, and only three women planned to disclose the abuse. Twenty-five women valued most their doctor's communicative approach with empathy or empowering and nine women valued most the instrumental approach. Eight women of the latter group wanted this combined with a communicative approach. After disclosure to the family doctor, a group of women (n = 20) perceived a real change in their possibilities to handle their situation. They appeared to be in a position we named: 'in transition', a state in which they started or continued a process of change. Another group of women (n = 13) appeared to be in a 'locked-up' position, a state without any prospect on change, feeling out of control and fearing the abuser. Three women reacted reserved towards change. Conclusion: A communicative approach, providing empathy and empowerment, is important to women in disclosing partner abuse. More than half of the women perceived possibilities for a change. Practice implications: Talking about abuse is an important step in a woman's process of change. Doctors should acknowledge the advantage of their position as a professional confidant and ask women about abuse. (c) 2007 Elsevier Ireland Ltd. All rights reserved

    Functional Outcome of Femoral versus Obturator Nerve Block after Total Knee Arthroplasty

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    Patients undergoing total knee arthroplasty often experience substantial postoperative pain, which may delay functional recovery and hospital discharge. We recently reported the short-term analgesic efficacy of a single-injection femoral nerve block after spinal anesthesia in total knee arthroplasty. We have now followed 30 patients a minimum of 1 year to determine the functional outcome and pain relief after femoral and obturator nerve block after total knee arthroplasty. Patients undergoing primary unilateral total knee arthroplasty were randomized to one of three treatment groups: (1) femoral nerve block; (2) obturator nerve block; or (3) placebo (sham block). At 6 weeks and 1 year, all three groups had similar total Hospital for Special Surgery knee scores and similar subscores such as range of motion, daily function, and resting and dynamic pain. The data support the usefulness of a peripheral nerve blockade in the context of a multimodal analgesic regimen and a tailored rehabilitation program to individual patients and institutions
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