3,869 research outputs found

    Push or Pull? An Empirical Analysis of the Demand for Individual Project Grants from the Swiss National Science Foundation

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    This study empirically analyses on the basis of a panel of grant requests to the Swiss National Science Foundation (SNSF. From the results it can be concluded, that the different scientific disciplines react in very different ways to the institutional and financial framework conditions set by the funding agency. Regarding the expansion of the tertiary educational system it can concluded that it has an impact on research funding in the form of two contrary influences. These two effects offset each other to the extent that they do not suffice to explain the rising trend in terms of the number of requests observable as from the year 2000.research funding, universities, panel estimations

    Electron-magnon scattering in elementary ferromagnets from first principles: lifetime broadening and band anomalies

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    We study the electron-magnon scattering in bulk Fe, Co, and Ni within the framework of many-body perturbation theory implemented in the full-potential linearized augmented-plane-wave method. To this end, a k\mathbf{k}-dependent self-energy (GTGT self-energy) describing the scattering of electrons and magnons is constructed from the solution of a Bethe-Salpeter equation for the two-particle (electron-hole) Green function, in which single-particle Stoner and collective spin-wave excitations (magnons) are treated on the same footing. Partial self-consistency is achieved by the alignment of the chemical potentials. The resulting renormalized electronic band structures exhibit strong spin-dependent lifetime effects close to the Fermi energy, which are strongest in Fe. The renormalization can give rise to a loss of quasiparticle character close to the Fermi energy, which we attribute to electron scattering with spatially extended spin waves. This scattering is also responsible for dispersion anomalies in conduction bands of iron and for the formation of satellite bands in nickel. Furthermore, we find a band anomaly at a binding energy of 1.5~eV in iron, which results from a coupling of the quasihole with single-particle excitations that form a peak in the Stoner continuum. This band anomaly was recently observed in photoemission experiments. On the theory side, we show that the contribution of the Goldstone mode to the GTGT self-energy is expected to (nearly) vanish in the long-wavelength limit. We also present an in-depth discussion about the possible violation of causality when an incomplete subset of self-energy diagrams is chosen

    Chromosome Evolution in New World Monkeys (Platyrrhini)

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    During the last decades, New World monkey (NWM, Platyrrhini, Anthropoideae) comparative cytogenetics has shed light on many fundamental aspects of genome organisation and evolution in this fascinating, but also highly endangered group of neotropical primates. In this review, we first provide an overview about the evolutionary origin of the inferred ancestral NWM karyotype of 2n = 54 chromosomes and about the lineage-specific chromosome rearrangements resulting in the highly divergent karyotypes of extant NWM species, ranging from 2n = 16 in a titi monkey to 2n = 62 in a woolly monkey. Next, we discuss the available data on the chromosome phylogeny of NWM in the context of recent molecular phylogenetic analyses. In the last part, we highlight some recent research on the molecular mechanisms responsible for the large-scale evolutionary genomic changes in platyrrhine monkeys. Copyright (C) 2012 S. Karger AG, Base

    Three-dimensional waves of excitation during Dictyostelium morphogenesis

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    Cells in Dictyostelium slugs follow well-defined patterns of motion. We found that the chemotactic cell response is controlled by a scroll wave of messenger concentration in the highly excitable prestalk zone of the slug that decays in the less-excitable prespore region into planar wave fronts. This phenomenon is investigated by numerical solutions of partial differential equations that couple local nonlinear kinetics and diffusive transport of the chemotactic signal. In the interface of both regions a complex twisted scroll wave is formed that reduces the wave frequency in the prespore zone. The spatio-temporal dynamics of waves and filaments are followed over 33 periods of rotation. These results yield an explanation of collective self-organized cell motion in a multicellular organism

    Water vapor transport in the lower mesosphere of the subtropics: a trajectory analysis

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    The Institute of Applied Physics operates an airborne microwave radiometer AMSOS that measures the rotational transition line of water vapor at 183.3 GHz. Water vapor profiles are retrieved for the altitude range from 15 to 75 km along the flight track. We report on a water vapor enhancement in the lower mesosphere above India and the Arabian Sea. The measurements took place on our flight from Switzerland to Australia and back in November 2005 conducted during EC- project SCOUT-O3. We find an enhancement of up to 25% in the lower mesospheric H<sub>2</sub>O volume mixing ratio measured on the return flight one week after the outward flight. The origin of the air is traced back by means of a trajectory model in the lower mesosphere and wind fields from ECMWF. During the outward flight the air came from the Atlantic Ocean around 25 N and 40 W. On the return flight the air came from northern India and Nepal around 25 N and 90 E. Mesospheric H<sub>2</sub>O measurements from Aura/MLS confirm the transport processes of H<sub>2</sub>O derived by trajectory analysis of the AMSOS data. Thus the large variability of H<sub>2</sub>O VMR during our flight is explained by a change of the winds in the lower mesosphere. This study shows that trajectory analysis can be applied in the mesosphere and is a powerful tool to understand the large variability in mesospheric H<sub>2</sub>O

    DIFFERENT TECHNICAL STRATEGIES AND BIOMECHANICAL ASPECTS OF DOUBLE POLlNG IN ELITE CROSS-COUNTRY SKIING

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    The purpose of this study was to analyse double poling (DP) regarding biomechanical performance determinants and different strategies. Eleven elite cross-country skiers performed DP at 85% of their maximal DP velocity (V85%) during roller skiing (treadmill; 1° inclination) while pole forces and selected joint angles were recorded. A 2D video evaluation categorised skiers into two different DP strategy groups. Strategy A group showed higher elbow (p < 0.01) and hip flexion angular velocities, smaller minimum elbow, knee and hip angles, higher peak pole force, shorter time to peak pole force and a longer relati.ve recovery time (p < 0.05), variables to which V85% was significantly correlated (p < 0.05). DP strategy A provides an effective model for technique and specific strength training while its physiological economy has to be further investigated

    Chromosome Evolution in New World Monkeys (Platyrrhini)

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    During the last decades, New World monkey (NWM, Platyrrhini, Anthropoideae) comparative cytogenetics has shed light on many fundamental aspects of genome organisation and evolution in this fascinating, but also highly endangered group of neotropical primates. In this review, we first provide an overview about the evolutionary origin of the inferred ancestral NWM karyotype of 2n = 54 chromosomes and about the lineage-specific chromosome rearrangements resulting in the highly divergent karyotypes of extant NWM species, ranging from 2n = 16 in a titi monkey to 2n = 62 in a woolly monkey. Next, we discuss the available data on the chromosome phylogeny of NWM in the context of recent molecular phylogenetic analyses. In the last part, we highlight some recent research on the molecular mechanisms responsible for the large-scale evolutionary genomic changes in platyrrhine monkeys. Copyright (C) 2012 S. Karger AG, Base

    Preparing a mechanical oscillator in non-Gaussian quantum states

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    We propose a protocol for coherently transferring non-Gaussian quantum states from optical field to a mechanical oscillator. The open quantum dynamics and continuous-measurement process, which can not be treated by the stochastic-master-equation formalism, are studied by a new path-integral-based approach. We obtain an elegant relation between the quantum state of the mechanical oscillator and that of the optical field, which is valid for general linear quantum dynamics. We demonstrate the experimental feasibility of such protocol by considering the cases of both large-scale gravitational-wave detectors and small-scale cavity-assisted optomechanical devices.Comment: 4 pages, 3 figure
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