6,041 research outputs found

    Risiken im Lebenszyklus: Theorie und Evidenz

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    Der einzelne Mensch ist im Lebensverlauf erheblichen biometrischen, ökonomischen, familiären und politischen Risiken ausgesetzt. Viele meinen, diese wären in den letzten Jahren größer geworden. Haben wir die richtigen Institutionen, um diese Risiken effizient abzudecken? Unter Institutionen verstehen wir individuelles Sparen, familiäre Hilfe, private Versicherungen und schließlich den Staat mit seinen Sozialversicherungen. Wo und wann funktionieren diese Institutionen? Wo und wann nicht? Was muss man tun, um sie zu verbessern? Wie sieht modernes "Social Risk Management" aus? Der erste Teil dieses Übersichtsbeitrags skizziert die wirtschaftstheoretischen Grundlagen des Sparverhaltens, der Portefeuillewahl und der Versicherungsnachfrage. Im Hauptteil werden die empirischen Befunde gesammelt, um im dritten Teil wirtschaftspolitische Schlussfolgerungen zu ziehen

    Optimizing passive acoustic sampling of bats in forests

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    Passive acoustic methods are increasingly used in biodiversity research and monitoring programs because they are cost-effective and permit the collection of large datasets. However, the accuracy of the results depends on the bioacoustic characteristics of the focal taxa and their habitat use. In particular, this applies to bats which exhibit distinct activity patterns in three-dimensionally structured habitats such as forests. We assessed the performance of 21 acoustic sampling schemes with three temporal sampling patterns and seven sampling designs. Acoustic sampling was performed in 32 forest plots, each containing three microhabitats: forest ground, canopy, and forest gap. We compared bat activity, species richness, and sampling effort using species accumulation curves fitted with the clench equation. In addition, we estimated the sampling costs to undertake the best sampling schemes. We recorded a total of 145,433 echolocation call sequences of 16 bat species. Our results indicated that to generate the best outcome, it was necessary to sample all three microhabitats of a given forest location simultaneously throughout the entire night. Sampling only the forest gaps and the forest ground simultaneously was the second best choice and proved to be a viable alternative when the number of available detectors is limited. When assessing bat species richness at the 1-km(2) scale, the implementation of these sampling schemes at three to four forest locations yielded highest labor cost-benefit ratios but increasing equipment costs. Our study illustrates that multiple passive acoustic sampling schemes require testing based on the target taxa and habitat complexity and should be performed with reference to cost-benefit ratios. Choosing a standardized and replicated sampling scheme is particularly important to optimize the level of precision in inventories, especially when rare or elusive species are expected

    The cost of surgical training: analysis of operative time for laparoscopic cholecystectomy

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    Background: Duration of surgery is a main cost factor of surgical training. The purpose of this analysis of operative times for laparoscopic cholecystectomies (LC) was to quantify the extra time and related costs in regards to the surgeons' experience in the operating room (OR). Methods: All LC performed between January 01, 2005 and December 31, 2008 in 46 hospitals reporting to the database of the Swiss Association for Quality Management in Surgery (AQC) were analyzed (n=10,010). Four levels of seniority were specified: resident (R), junior consultant (JC), senior consultant (SC), and attending surgeon (AS). The differences in operative time according to seniority were investigated in a multivariable log-linear and median regression analysis controlling for possible confounders. The OR costs were calculated by using a full cost rate in a teaching hospital. Results: A total of 9,208 LC were available for analysis; 802 had to be excluded due to missing data (n=212) or secondary major operations (n=590). Twenty-eight percent of the LC were performed by R as teaching operations (n=2,591). Compared with R, the multivariable analysis of operative time showed a median difference of −2.5min (−9.0; 4.8) for JC and −18min (−25; −11) for SC and −28min (−35; −10) for AS, respectively. The OR minute costs were €17.57, resulting in incremental costs of €492 (159; 615) per operation in case of tutorial assistance. Conclusions: The proportion of LC performed as tutorial assistance for R remains low. Surgical training in the OR causes relevant case-related extra time and therefore cost

    EFFECT OF AN IN-SEASON LIVING MULCH ON LEACHING OF INORGANIC NITROGEN IN CAULIFLOWER (BRASSICA OLERACEA L. VAR. BOTRYTIS) CROPPING IN SLOVENIA, GERMANY AND DENMARK

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    Vegetables with a high nitrogen demand such as cauliflower may cause intensive leaching of nitrate to the environment in conventional as well as in organic production. In organic cropping systems, the use of an in-season living mulch may decrease the risk of nitrate leaching after harvest when left growing in the field to the end of the leaching season in spring. The aim of this study was to investigate the effect of growing an in-season living mulch including legumes on the risk of leaching of inorganic nitrogen over winter, and soil nitrogen availability the following spring. Three field experiments were carried out in Slovenia, Germany and Denmark in the frame of the Interveg project (CORE organic II). Evaluation of soil inorganic nitrogen content was done at planting, at harvest, in late autumn and in spring to a depth of 0.6, 0.9 or 1.5 m as well as nitrogen uptake by the biomass. This study reports preliminary results of the first year of experiments on soil inorganic nitrogen at harvest and the end of the leaching season. They indicate that living mulches may have a potential to decrease the nitrate leaching risk depending on the design of the cropping system

    Relativistic and Radiative Energy Shifts for Rydberg States

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    We investigate relativistic and quantum electrodynamic effects for highly-excited bound states in hydrogenlike systems (Rydberg states). In particular, hydrogenic one-loop Bethe logarithms are calculated for all circular states (l = n-1) in the range 20 <= n <= 60 and successfully compared to an existing asymptotic expansion for large principal quantum number n. We provide accurate expansions of the Bethe logarithm for large values of n, for S, P and circular Rydberg states. These three expansions are expected to give any Bethe logarithms for principal quantum number n > 20 to an accuracy of five to seven decimal digits, within the specified manifolds of atomic states. Within the numerical accuracy, the results constitute unified, general formulas for quantum electrodynamic corrections whose validity is not restricted to a single atomic state. The results are relevant for accurate predictions of radiative shifts of Rydberg states and for the description of the recently investigated laser-dressed Lamb shift, which is observable in a strong coherent-wave light field.Comment: 8 pages; RevTeX

    Cultural differences in postnatal quality of life among German-speaking women - a prospective survey in two countries.

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    Assessment of quality of life after childbirth is an important health-outcome measurement for new mothers and is of special interest in midwifery. The Mother-Generated Index (MGI) is a validated instrument to assess postnatal quality of life. The tool has not been applied for making a cross-cultural comparison before. This study investigated (a) responses to the MGI in German-speaking women in Germany and Switzerland; and (b) associations between MGI scores on the one hand and maternity and midwifery care on the other

    Itinerant and Localized Magnetization Dynamics in Antiferromagnetic Ho

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    Using femtosecond time-resolved resonant magnetic x-ray diffraction at the Ho L 3 absorption edge, we investigate the demagnetization dynamics in antiferromagnetically ordered metallic Ho after femtosecond optical excitation. Tuning the x-ray energy to the electric dipole ( E 1 , 2 p → 5 d ) or quadrupole ( E 2 , 2 p → 4 f ) transition allows us to selectively and independently study the spin dynamics of the itinerant 5 d and localized 4 f electronic subsystems via the suppression of the magnetic (2 1 3 − τ ) satellite peak. We find demagnetization time scales very similar to ferromagnetic 4 f systems, suggesting that the loss of magnetic order occurs via a similar spin-flip process in both cases. The simultaneous demagnetization of both subsystems demonstrates strong intra-atomic 4 f − 5 d exchange coupling. In addition, an ultrafast lattice contraction due to the release of magneto-striction leads to a transient shift of the magnetic satellite peak

    Simplicial quantum dynamics

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    Present-day quantum field theory can be regularized by a decomposition into quantum simplices. This replaces the infinite-dimensional Hilbert space by a high-dimensional spinor space and singular canonical Lie groups by regular spin groups. It radically changes the uncertainty principle for small distances. Gaugeons, including the gravitational, are represented as bound fermion-pairs, and space-time curvature as a singular organized limit of quantum non-commutativity. Keywords: Quantum logic, quantum set theory, quantum gravity, quantum topology, simplicial quantization.Comment: 25 pages. 1 table. Conference of the International Association for Relativistic Dynamics, Taiwan, 201
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