32,536 research outputs found
EAGLE 2006 – Multi-purpose, multi-angle and multi-sensor in-situ and airborne campaigns over grassland and forest
EAGLE2006 - an intensive field campaign - was carried out in the Netherlands from the 8th until the
18th of June 2006. Several airborne sensors - an optical imaging sensor, an imaging microwave
radiometer, and a flux airplane – were used and extensive ground measurements were conducted over
one grassland (Cabauw) site and two forest sites (Loobos & Speulderbos) in the central part of the
Netherlands, in addition to the acquisition of multi-angle and multi-sensor satellite data. The data set is
both unique and urgently needed for the development and validation of models and inversion
algorithms for quantitative surface parameter estimation and process studies. EAGLE2006 was led by
the Department of Water Resources of the International Institute for Geo-Information Science and
Earth Observation and originated from the combination of a number of initiatives coming under
different funding. The objectives of the EAGLE2006 campaign were closely related to the objectives of
other ESA Campaigns (SPARC2004, Sen2Flex2005 and especially AGRISAR2006). However, one
important objective of the campaign is to build up a data base for the investigation and validation of the
retrieval of bio-geophysical parameters, obtained at different radar frequencies (X-, C- and L-Band)
and at hyperspectral optical and thermal bands acquired over vegetated fields (forest and grassland). As
such, all activities were related to algorithm development for future satellite missions such as Sentinels
and for satellite validations for MERIS, MODIS as well as AATSR and ASTER thermal data
validation, with activities also related to the ASAR sensor on board ESA’s Envisat platform and those
on EPS/MetOp and SMOS. Most of the activities in the campaign are highly relevant for the EU
GEMS EAGLE project, but also issues related to retrieval of biophysical parameters from MERIS and
MODIS as well as AATSR and ASTER data were of particular relevance to the NWO-SRON EcoRTM
project, while scaling issues and complementary between these (covering only local sites) and global
sensors such as MERIS/SEVIRI, EPS/MetOP and SMOS were also key elements for the SMOS cal/val
project and the ESA-MOST DRAGON programme. This contribution describes the mission objectives
and provides an overview of the airborne and field campaigns
Local Density of States and Angle-Resolved Photoemission Spectral Function of an Inhomogeneous D-wave Superconductor
Nanoscale inhomogeneity seems to be a central feature of the d-wave
superconductivity in the cuprates. Such a feature can strongly affect the local
density of states (LDOS) and the spectral weight functions. Within the
Bogoliubov-de Gennes formalism we examine various inhomogeneous configurations
of the superconducting order parameter to see which ones better agree with the
experimental data. Nanoscale large amplitude oscillations in the order
parameter seem to fit the LDOS data for the underdoped cuprates. The
one-particle spectral function for a general inhomogeneous configuration
exhibits a coherent peak in the nodal direction. In contrast, the spectral
function in the antinodal region is easily rendered incoherent by the
inhomogeneity. This throws new light on the dichotomy between the nodal and
antinodal quasiparticles in the underdoped cuprates.Comment: 5 pages, 9 pictures. Phys. Rev. B (in press
Magnetic control of the pair creation in spatially localized supercritical fields
We examine the impact of a perpendicular magnetic field on the creation mechanism of electron-positron pairs in a supercritical static electric field, where both fields are localized along the direction of the electric field. In the case where the spatial extent of the magnetic field exceeds that of the electric field, quantum field theoretical simulations based on the Dirac equation predict a suppression of pair creation even if the electric field is supercritical. Furthermore, an arbitrarily small magnetic field outside the interaction zone can bring the creation process even to a complete halt, if it is sufficiently extended. The mechanism for this magnetically induced complete shutoff can be associated with a reopening of the mass gap and the emergence of electrically dressed Landau levels
Lie bialgebras of generalized Witt type
In a paper by Michaelis a class of infinite-dimensional Lie bialgebras
containing the Virasoro algebra was presented. This type of Lie bialgebras was
classified by Ng and Taft. In this paper, all Lie bialgebra structures on the
Lie algebras of generalized Witt type are classified. It is proved that, for
any Lie algebra of generalized Witt type, all Lie bialgebras on are
coboundary triangular Lie bialgebras. As a by-product, it is also proved that
the first cohomology group is trivial.Comment: 14 page
Mott-Peierls Transition in the extended Peierls-Hubbard model
The one-dimensional extended Peierls-Hubbard model is studied at several band
fillings using the density matrix renormalization group method. Results show
that the ground state evolves from a Mott-Peierls insulator with a correlation
gap at half-filling to a soliton lattice with a small band gap away from
half-filling. It is also confirmed that the ground state of the Peierls-Hubbard
model undergoes a transition to a metallic state at finite doping. These
results show that electronic correlations effects should be taken into account
in theoretical studies of doped polyacetylene. They also show that a
Mott-Peierls theory could explain the insulator-metal transition observed in
this material.Comment: 4 pages with 3 embedded eps figure
Liquid-gas Phase Transition in Strange Hadronic Matter with Weak Y-Y Interaction
The liquid-gas phase transition in strange hadronic matter is reexamined by
using the new parameters about the interaction deduced from
recent observation of double hypernucleus. The
extended Furnstahl-Serot-Tang model with nucleons and hyperons is utilized. The
binodal surface, the limit pressure, the entropy, the specific heat capacity
and the Caloric curves are addressed. We find that the liquid-gas phase
transition can occur more easily in strange hadronic matter with weak Y-Y
interaction than that of the strong Y-Y interaction.Comment: 10 pages, 7 figure
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The heterogeneous effects of CSR dimensions on financial performance -a new approach for CSR measurement
This paper investigates the differential effects of corporate social responsibility (CSR) dimensions on corporate financial performance (CFP) across sectors in China. This research uses a unique data set provided by China Stock Market and Accounting Research (CSMAR), showing expenditure on CSR programs from 568 Chinese publicly traded firm-year observations from 2008 to 2017. Compared to previous studies using scores produced by extra-financial rating agencies, this research quantifies CSR efforts by corporate expenditure on CSR practices, which offers quantitative and precise information in explaining the CSR-CFP link. The results show that the dimension of the environment has negative effects on financial performance in capital-intensive manufacturing industries. The impact of HR expenditure on CFP is negative in the tertiary sector and resource-intensive manufacturing industries. However, CSR investments in the community are positively related to financial performance in resource-intensive industries and other secondary sector (mining, construction, and utilities). Firms, in general, could gain benefits when spending more on business and financial stakeholders
Design, Synthesis and Relaxivity Behaviour of mRNA Targeting Contrast Agents
Introduction: Magnetic Resonance Imaging (MRI) is one of the most important diagnostic tools available in medicine. The specificity and sensitivity of MRI can be further enhanced by the introduction of contrast agents (CAs). As many clinically valuable targets reside inside the cell membrane, the development of efficient intracellular targeted MR contrast agent is required. Potential intracellular targets would be DNA, mRNA or protein/enzymes. The prerequisite for the intracellular targeting is not only the efficient delivery of probes inside the cell but also the colocalization with the target. The objective of the present study is to design and synthesize efficient intracellular MR contrast agents [1] which include three functional domains (i) Gd based MR reporter part (ii) antisense PNA to target mRNA (iii) cell penetrating peptide (CPP) or cholesterol as the delivery agent. The antisense PNA can hybridize uniquely to the complementary mRNA and provides cell specific targeting for cells containing the mRNA. Thus, the expression of the corresponding gene can be visualized non invasively by in vivo MR imaging. Methods: The conjugates were synthesized by continuous solid phase synthesis. Cellular uptake was confirmed by fluorescence microscopy, spectroscopy and MRI of labeled cells. Results: CPP conjugated mRNA targeting CAs were taken up efficiently into cells by an exclusively endosomal mechanism. A subtoxic labeling concentration at low micromolar range was sufficient to enhance significant MR imaging contrast. Cell free binding assays proved a specific interaction with a synthetic target. However, because of the vesicular entrapment, it can be expected that there would be a lack of specific interaction between CA and mRNA located in the cytosol. In order to overcome this problem, cholesterol conjugated CAs are designed and synthesized [2]. The idea behind cholesterol coupling was from the already published report [3] where covalent conjugates of cholesterol and siRNAs were facilitating cellular import and were able to silence protein expression effectively. Initial results have shown that these agents were delivered more efficiently than CPP conjugated CAs. Unfortunately, they were also entrapped in vesicles. Both types of CA were able to enhance contrast in labeled target containing as well as non-targeted parent cells. However, there was not efficient colocalization and specific interaction of CA and target mRNA achievable to be exploited for MR imaging purposes. Conclusion: CPP or lipid coupled CAs are internalized efficiently into cells. However, vesicular entrapment prevented sufficient specific interaction between CA and mRNA. Further modifications are required to achieve the release from endosomes or a direct uptake into the cytosol
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