Sökresultat

This study reconstructs the regional vegetation and climate dynamics between the upper Late Pleistoceneand Holocene around Pian del Lago, a coastal mountain marshland located at 831 m asl in westernLiguria (NW-Italy), based on the pollen analysis of a 13 m-long sediment core. The record provided aunique opportunity to study a poorly documented period in northern Italy and across many parts ofsouth

An experimental study on the duration of load effects in a glued shear plate dowel joint was conducted. The joint design features a single large diameter dowel for load transfers between members, via external steel plates, which are bonded to the timber with a low stiffness bond line. Due to the low bond line stiffness, the timber element is subjected to a close to uniform shear stress distributio

Cardiovascular disease is common among patients with chronic obstructive pulmonary disease (COPD). Takotsubo syndrome (TTS) is a transient cardiac disorder that, in its typical form, involves left ventricular dysfunction with apical ballooning and mimics acute coronary syndrome (ACS). "Bronchogenic TTS" has been proposed as a specific form of TTS (during severe acute dyspnea in asthma or COPD) witCardiovascular disease is common among patients with chronic obstructive pulmonary disease (COPD). Takotsubo syndrome (TTS) is a transient cardiac disorder that, in its typical form, involves left ventricular dysfunction with apical ballooning and mimics acute coronary syndrome (ACS). "Bronchogenic TTS" has been proposed as a specific form of TTS (during severe acute dyspnea in asthma or COPD) wit

Premise of research. Phenotypic traits that consistently mediate species’ responses to environmental variation (functional traits) provide a promising approach toward generalizing ecological and evolutionary patterns and thereby gaining insights into the processes generating them. In the plant functional ecology literature, most trait-based studies have focused on traits mediating either resource

Environmental governance relies on the translation of socioecological knowledge across disciplines and cultural–political boundaries. Comparatively few studies have, however, examined how such expert knowledge is translated back into the local contexts where projects are implemented. This article explores these processes of translation for the case of forest-based carbon offsetting using a case st

The free-electron laser facility FLASH at DESY (Hamburg) was upgraded during a five month shutdown in winter 2009 [1]. Part of this upgrade was the installation of a direct seeding experiment in the XUV spectral range. Besides all components for transport and diagnostics of the photon beam into and out of the accelerator environment, a new 10m long variable-gap undulator was installed upstream of

Starting from next year the technical feasibility of a direct seeding scheme at 30 and 13 nm will be studied at the Free-electron LASer in Hamburg (FLASH). During a major shutdown the SASE-FEL facility will be upgraded and it is planned to install in addition a high-harmonic generation (HHG) seed laser, a new chain of 10 m variable gap un-dulators and a dedicated commissioning beamline for photon

The quasi-stationary state characterizing the saturation of a single-pass free-electron laser is governed by the Vlasov equation obtained by performing the continuum limit of the Colson-Bonifacio model. By means of a statistical treatment, this approach allows to predict analytically the saturated laser intensity as well as the final electron-beam energy distribution. In this paper we consider the

The optical klystron installed on the Elettra storage-ring is normally used as interaction region for an oscillator free-electron laser, but, removing the optical cavity and using an external seed laser, one obtains an effective scheme for single-pass harmonic generation. In this configuration the high-power external laser is synchronized with the electron beam entering the first undulator of the

UV absorption from carbon nanoparticles is a very interesting astrophysical topic. The prominent hump centred at 217.5 nm is the most dominant feature in the interstellar extinction curve and also the most controversial and a long-standing problem in astrophysics. At the University of Milano an experimental set-up based on a Pulsed Microplasma Cluster Source has been developed for the investigatio

In a Storage-Ring Free-Electron Laser (SRFEL) giant pulses can be produced by the interaction between the light stored in the optical cavity and an electron beam with low energy-spread (cold beam). This interplay produces the heating of the beam. After the generation of a single giant pulse the overlap between electrons and radiation is periodically prevented for a time necessary to dump the energ

In a storage-ring free-electron laser (FEL), the onset and growth of intra-cavity power at the resonator wavelength can be naturally accompanied by coherent emission at higher harmonics. Contrary to what happens in singlepass linac-based devices, the electron beam is re-circulated in the storage ring and, while the microbunching becomes "thermalized" from turn to turn, the evolution of other bunch

Single-pass free-electron lasers constitute an example of systems with long-range interactions. The light-particle interplay leading to the power growth and successive relaxation towards a quasi-stationary state is governed by the Vlasov equation. A maximum entropy principle inspired to Lynden-Bell's theory of "violent relaxation" for the Vlasov equation can be invoked to analytically characterize

Coherent radiation from a relativistic electron beam is a valuable way to overcome the present limitations of conventional lasers and synchrotron radiation light sources. The typical scheme has electrons, directly from a linac, in a single-pass interaction with a laser pulse in the presence of a static undulator magnetic field. We demonstrate that a storage-ring free-electron laser can also achiev