2,263 research outputs found

    The impact of introducing patient co-payments in Germany on the use of IVF and ICSI:a price-elasticity of demand assessment

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    BACKGROUND: Authorities concerned by rising healthcare costs have a tendency to target reproductive treatments because of the perception that infertility is a low priority. In 2004 German health authorities introduced a 50% co-payment for patients, in an effort to save cost. We explored the impact of this pricing policy on the utilization of reproductive treatments in Germany. METHODS: Using aggregated annual in-vitro fertilization (IVF) and intracytoplasmic sperm injection (ICSI) cycle data in Germany, we evaluated the relationship between changes in the number of cycles in relation to changes in costs faced by consumers following the introduction of a patient co-payment from 'no fees' to (sic)1500-2000 by estimating the short-run price-elasticity of demand. The impact of introducing patient co-payments for IVF/ICSI on the likelihood of switching to other low-cost fertility treatments was evaluated using the cross-price elasticity methodology. RESULTS: The reduction in demand for IVF and ICSI cycles in the year following the introduction of patient co-payments resulted in elasticities of -0.41 and -0.34, respectively. The price-elasticity for the combined reduction of IVF/ICSI in relation to the co-payment was estimated to be -0.36. The cross-price elasticity for clomifene was close to zero (-0.01) suggesting that demand for these interventions are independent of each other and no substitution occurred. CONCLUSIONS: We report price elasticities for IVF and ICSI of -0.41 and -0.34 after introducing a (sic)1500-2000 co-payment. These findings likely represent short-run elasticities that are likely to vary over time as factors that influence the supply and demand for fertility treatments change

    Neutron resonance capture applied to some prehistoric bronze axes

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    The elemental analysis of materials and objects on the basis of neutron resonance capture by nuclei as a function of neutron energy is briefly explained. The feasibility of neutron resonance capture analysis (NRCA) is demonstrated with five prehistoric “bronze” axes of different kinds and complex elemental compositions. Attention is paid to the occurrence of indium as a trace element in these artefacts

    Microwave Transport in Metallic Single-Walled Carbon Nanotubes

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    The dynamical conductance of electrically contacted single-walled carbon nanotubes is measured from dc to 10 GHz as a function of source-drain voltage in both the low-field and high-field limits. The ac conductance of the nanotube itself is found to be equal to the dc conductance over the frequency range studied for tubes in both the ballistic and diffusive limit. This clearly demonstrates that nanotubes can carry high-frequency currents at least as well as dc currents over a wide range of operating conditions. Although a detailed theoretical explanation is still lacking, we present a phenomenological model of the ac impedance of a carbon nanotube in the presence of scattering that is consistent with these results.Comment: Added reference

    Electron-hole symmetry in a semiconducting carbon nanotube quantum dot

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    Optical and electronic phenomena in solids arise from the behaviour of electrons and holes (unoccupied states in a filled electron sea). Electron-hole symmetry can often be invoked as a simplifying description, which states that electrons with energy above the Fermi sea behave the same as holes below the Fermi energy. In semiconductors, however, electron-hole symmetry is generally absent since the energy band structure of the conduction band differs from the valence band. Here we report on measurements of the discrete, quantized-energy spectrum of electrons and holes in a semiconducting carbon nanotube. Through a gate, an individual nanotube is filled controllably with a precise number of either electrons or holes, starting from one. The discrete excitation spectrum for a nanotube with N holes is strikingly similar to the corresponding spectrum for N electrons. This observation of near perfect electron-hole symmetry demonstrates for the first time that a semiconducting nanotube can be free of charged impurities, even in the limit of few-electrons or holes. We furthermore find an anomalously small Zeeman spin splitting and an excitation spectrum indicating strong electron-electron interactions.Comment: 12 pages, 4 figure

    Neutron Resonance Spectroscopy of 106Pd, and 108Pd from 20–2000 eV

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    Parity nonconserving asymmetries have been measured in p-wave resonances of 106Pd and 108Pd. The data analysis requires knowledge of the neutron resonance parameters. Transmission and capture γ-ray yields were measured for En=20–2000 eV with the time-of-flight method at the Los Alamos Neutron Science Center (LANSCE). A total of 28 resonances in 106Pd and 32 resonances in 108Pd were studied. The resonance parameters for 106Pd are new for all except one resonance. In 108Pd six new resonances were observed and the precision improved for many of the resonance parameters. A Bayesian analysis was used to assign orbital angular momentum for the resonances studied

    Cost-minimisation analysis of a treat-and-extend regimen with anti-VEGFs in patients with neovascular age-related macular degeneration

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    PURPOSE: Although intraocular anti-vascular endothelial growth factors (anti-VEGFs) are effective as treatment of neovascular age-related macular degeneration (nAMD), the (economic) burden on the healthcare system is considerable. A treat-and-extend (T&E) regimen is associated with a lower number of injections without compromising the effectiveness and can therefore help optimise nAMD treatment. This study investigates the per-patient costs associated with nAMD treatment, when using aflibercept, bevacizumab, or ranibizumab with a T&E regimen. METHODS: In this cost-minimisation model, the per-patient costs in the Netherlands were modelled using a healthcare payers’ perspective over a 3-year time horizon with the assumption that efficacy of treatments is similar. Additionally, the break-even price of the different anti-VEGFs was calculated relative to the cheapest option and injection frequency. RESULTS: The injection frequency varied from 14.2 for aflibercept to 27.4 for bevacizumab in 3 years. Nonetheless, bevacizumab remains the cheapest treatment option (€14,215), followed by aflibercept (€18,202) and ranibizumab (€31,048). The medication covers the majority of the per-patient costs for aflibercept and ranibizumab, while administration covers the majority of the per-patient costs for bevacizumab. The break-even prices of aflibercept and ranibizumab are respectively €507 and €60.58 per injection. Brolucizumab was included in the scenario analysis and was more expensive than aflibercept (€20,446). Brolucizumab should reduce to 13.8 injections over 3 years to be as costly as aflibercept. CONCLUSION: Bevacizumab is the cheapest anti-VEGF treatment. The list prices of all anti-VEGFs should reduce to be as costly as bevacizumab. Aflibercept is the second-choice treatment and so far brolucizumab is not

    Molecular dynamics with coupling to an external bath

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    In molecular dynamics (MD) simulations the need often arises to maintain such parameters as temperature or pressure rather than energy and volume, or to impose gradients for studying transport properties in nonequilibrium MD. A method is described to realize coupling to an external bath with constant temperature or pressure with adjustable time constants for the coupling. The method is easily extendable to other variables and to gradients, and can be applied also to polyatomic molecules involving internal constraints. The influence of coupling time constants on dynamical variables is evaluated. A leap‐frog algorithm is presented for the general case involving constraints with coupling to both a constant temperature and a constant pressure bath
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