1,281 research outputs found
Studies on Structure and Dynamics of Components of Phytochrome Mediated Light Signaling in Plants and Cyanobacteria
From a structural point of view, phytochrome mediated light signaling in plants and bacteria constitutes a scarcely understood system. Albeit the tremendous research activity in the field, no X-ray or NMR-based structural information is available. For the first time now, the crystal structures of two cyanobacterial response regulators (RR), which directly interact with bacterial phytochrome receptors, have been solved. This could be accomplished by heterologous expression, purification and crystallization of the proteins, and X-ray structure determination, employing multiple anomalous wavelength dispersion (MAD) and molecular replacement (MR) techniques
Measurement on Different MLI Systems Between 77 K and 4 K and their Application in Cryogenic Engineering
Precise thermal measurements were done on different types of large surface MLI samples under various boundary conditions. The measurements were focused on the use of MLI for large industrial plants considering quick and simple installation. The results of the measurements aim at optimising MLI parameters, which control the thermal behaviour. Practical recommendations of MLI materials and their installation are given
Test Station for a 30 m long Superconducting Link
The Large Hadron Collider (LHC) requires distribution of high electrical currents in the limited space of LHC tunnel. Four superconducting links of about 76 m length and one of 510 m will be installed in the tunnel to carry 6Â kA and 600 A. For validation of the longest link a test station was designed which is presently under construction. The design will permit the test station to be adapted for other links and/or cables as well. It will operate either in pool boiling mode, in order to measure thermal loads, or in forced super-critical helium flow mode to simulate real operation. Inlet pressure is 1.2 bar to 3 bar. Inlet temperature is adjustable from 4.4 K up to about 20 K. The station is being prepared to validate the LHC model link, consisting of 48 superconducting cables, each operating at 600 A between 4.5 K and 5.4 K. This article describes features of the equipment
Plant Physiology LEAF SHEATHS AND THE INHIBITION O F GERMINATION OF YOUNG AXILLARY BUDS IN SUGARCANE(')S(2)
ABSTRACT The younger parts of field-grown stalks of the sugarcane variety Co 205, with spindle included but with leaf blades trimmed back, were grown in distilled water in the dark. .When sheaths were left intact, few buds germinated; axillary shoots developed only from mature nodes. When sheaths were removed, many more buds germinated; axillary shoots developed from both older immature and mature nodes. The results, applied to normal stalk development, suggest that the sheath helps to control tillering. Germination of young bdds could, be inhibited by the sheath when the sheath is tight as around upper cylindrical nodes, but not when the sheath is loose as around lower obconic nodes at the base of the stalk
UKRmol+: A suite for modelling electronic processes in molecules interacting with electrons, positrons and photons using the R-matrix method
UKRmol+ is a new implementation of the time-independent UK R-matrix electron-molecule scattering code. Key features of the implementation are the use of quantum chemistry codes such as Molpro to provide target molecular orbitals; the optional use of mixed Gaussian – B-spline basis functions to represent the continuum and improved configuration and Hamiltonian generation. The code is described, and examples covering electron collisions from a range of targets, positron collisions and photoionization are presented. The codes are freely available as a tarball from Zenodo
Design of the second series 15 m LHC prototype dipole magnet cryostats
A first series of six LHC 10 m long prototype dipole magnets and cryostats have been manufactured in European Industry and the assembled cryo-magnets tested singly and connected in series in a test string at CERN between March 1994 and December 1996. During the same period, an evolution in the requirements for LHC cryogenics distribution has lead the project management to adopt a separate cryo-distribution line running parallel to the LHC machine1. The former standard LHC half-cell, made up of a short straight section unit and four 10 m dipoles, has been discarded and replaced with one composed of a short straight section unit and three 15 m dipoles. The new 15 m LHC dipole magnet cryostats are described. These units house the dipole magnet cold mass standing on three low heat in-leak support columns, and enclosed within an actively cooled radiation screen operating at 4.5-20 K and an actively cooled thermal shield operating at 50-75 K
Electron correlation and short-range dynamics in attosecond angular streaking
We employ the R matrix with time-dependence method to study attosecond angular streaking of F−. Using this negative ion, free of long-range Coulomb interactions, we elucidate the role of short-range electron correlation effects in an attoclock scheme. Through solution of the multielectron time-dependent Schrödinger equation, we aim to bridge the gap between experiments using multielectron targets, and one-electron theoretical approaches. We observe significant negative offset angles in the photoelectron momentum distributions, despite the short-range nature of the binding potential. We show that the offset angle is sensitive to the atomic structure description of the residual F atom. We also investigate the response of co- and counter-rotating electrons, and observe an angular separation in their emissio
Effects of summary knowledge of results in motor skills acquisition
The effects of Summary Knowledge of Results (KR) were tested, using 30 volunteers and a positioning task in which a tennis ball had to be transported in 30 trials, following a specific sequence and with a target time of 3000 msec. Ten minutes after the acquisition phase, the transfer test was performed with 10 trials of different sequences and target times. The retention test took place 24 hours later with 10 trials of the same sequence and target time as the acquisition phase. In the transfer and retention tests, KR was not provided. The volunteers were randomly divided into three groups: G5 (KR every five trials); G3 (KR every three trials) and G100 (KR every trial). The results showed that G3 had a smaller absolute error than G100. However, G3 and G5 had a smaller constant error than G100. In general, the effects of G3 and G5 on motor skill acquisition could be caused by the lower KR frequency, which was 33% and 20% respectively.El efecto del conocimiento de los resultados (KR) resumen ha sido probado por 30 voluntarios en tarea de posicionamiento que requiere el transporte de una pelota de tenis en una secuencia específica con el tiempo objetivo de 3000 ms. en 30 ensayos. Diez minutos después de la fase de adquisición se jugó el test de transferencia con 10 ensayos con diferente secuencia y tempo objetivo. La retención se realizó la prueba 24 horas más tarde con la misma secuencia y tiempo objetivo fase de adquisición. En los testes de transferencia y retención de la CR no fue suministrado. Los voluntarios fueron divididos aleatoriamente en tres grupos: G5 (CR después de 5 ensayos); G3 (CR después de 3 ensayos) y G100 (CR en todos los ensayos). El resultado mostró que G3 tuvieron menor error absoluto que G100. Sin embargo, G3 y G5 se han registrado menor error constante que G100. En general, los efectos de G3 y G5 en la adquisición de las habilidades motoras pueden ser causados por la disminución de frecuencias CR, que fueron 33% y 20 %, respectivamente.O efeito do conhecimento de resultados (CR) sumário foi testado por 30 voluntários em uma tarefa de posicionamento a qual exigia o transporte de uma bola de tênis em uma sequência específica com tempo alvo de 3000 mseg. durante 30 tentativas. Dez minutos após a fase de aquisição foi desempenhado o teste de transferência com 10 tentativas com sequência e tempo alvo diferente. O teste de retenção foi realizado 24 horas mais tarde com a mesma sequência e tempo alvo da fase de aquisição. Nos testes de transferência e retenção o CR não foi fornecido. Os voluntários foram aleatoriamente divididos em três grupos: G5 (CR depois de 5 tentativas); G3 (CR depois de 3 tentativas) e G100 (CR em todas tentativas). O resultado mostrou que G3 apresentou menor erro absoluto que G100. Entretanto, G3 e G5 registraram menor erro constante que G100. Em geral, os efeitos de G3 e G5 sobre a aquisição de habilidades motoras podem ser causados pelas frequências reduzidas de CR, que foram de 33% e 20%, respectivamente
Convergence to stable laws for multidimensional stochastic recursions: the case of regular matrices
Given a sequence of i.i.d.\ random variables with
generic copy , we consider the random
difference equation (RDE) , and assume
the existence of such that \lim_{n \to \infty}(\E{\norm{M_1 ...
M_n}^\kappa})^{\frac{1}{n}} = 1 . We prove, under suitable assumptions, that
the sequence , appropriately normalized, converges in
law to a multidimensional stable distribution with index . As a
by-product, we show that the unique stationary solution of the RDE is
regularly varying with index , and give a precise description of its
tail measure. This extends the prior work http://arxiv.org/abs/1009.1728v3 .Comment: 15 page
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