444 research outputs found
The Dirichlet and the weighted metrics for the space of Kahler metrics
In this work we study the intrinsic geometry of the space of Kahler metrics
under various Riemannian metrics. The first part is on the Dirichlet metric. We
motivate its study, we compute its curvature, and we make links with the Calabi
metric, the K-energy, the degenerate complex Hessian equation. The second part
is on the weighted metrics, for which we investigate as well their geometric
properties.Comment: 33 pages, new sections on the weighted metric
Energy and angular momentum sharing in dissipative collisions
Primary and secondary masses of heavy reaction products have been deduced
from kinematics and E-ToF measurements, respectively, for the direct and
reverse collisions of 93Nb and 116Sn at 25 AMeV. Light charged particles have
also been measured in coincidence with the heavy fragments.
Direct experimental evidence of the correlation of energy-sharing with net
mass transfer has been found using the information from both the heavy
fragments and the light charged particles.
The ratio of Hydrogen and Helium multiplicities points to a further
correlation of angular momentum sharing with net mass transfer.Comment: 21 pages, 20 figures. Submitted to European Physics Journal
GM1 and GM2 gangliosides: recent developments.
AbstractGM1 and GM2 gangliosides are important components of the cell membrane and play an integral role in cell signaling and metabolism. In this conceptual overview, we discuss recent developments in our understanding of the basic biological functions of GM1 and GM2 and their involvement in several diseases. In addition to a well-established spectrum of disorders known as gangliosidoses, such as Tay-Sachs disease, more and more evidence points at an involvement of GM1 in Alzheimer's and Parkinson's diseases. New emerging methodologies spanning from single-molecule imaging in vivo to simulations in silico have complemented standard studies based on ganglioside extraction
sound archives accessibility
International audience; The paper analyses the conflicting issues that arise when dealing with Intangible Cultural Heritage (ICH) held in audio digital archives, when the demand for open access conflicts with ownership rights and ethical issues. It describes two case studies in order to evaluate the procedures used for doing research on oral materials while respecting the rights of others. The first refers to the activities carried on at the Phonothèque de la Maison méditerranéenne des sciences de l'homme, a French sound archive; the second refers to the solutions envisaged by an Italian research project, Grammo-foni. Le soffitte della voce (Gra.fo), jointly carried out by Scuola Normale Superiore of Pisa and the University of Siena
Phenotypic and Molecular-Phylogenetic Analysis Provide Novel Insights into the Diversity of Curtobacterium flaccumfaciens.
A multiphasic approach was used to decipher the phenotypic features, genetic diversity, and phylogenetic position of 46 Curtobacterium spp. strains isolated from dry beans and other annual crops in Iran and Spain. Pathogenicity tests, resistance to arsenic compounds, plasmid profiling and BOX-PCR were performed on the strains. Multilocus sequence analysis (MLSA) was also performed on five housekeeping genes (i.e., atpD, gyrB, ppk, recA, and rpoB) of all the strains, as well as five pathotype strains of the species. Pathogenicity test showed that six out of 42 strains isolated in Iran were nonpathogenic on common bean. Despite no differences found between pathogenic and nonpathogenic strains in their plasmid profiling, the former were resistant to different concentrations of arsenic, while the latter were sensitive to the same concentrations. Strains pathogenic on common bean were polyphyletic with at least two evolutionary lineages (i.e., yellow-pigmented strains versus red/orange-pigmented strains). Nonpathogenic strains isolated from solanaceous vegetables were clustered within either the strains of C. flaccumfaciens pv. flaccumfaciens or different pathovars of the species. The results of MLSA and BOX-PCR analysis were similar to each other and both methods were able to discriminate the yellow-pigmented strains from the red/orange-pigmented strains. A comprehensive study of a worldwide collection representing all five pathovars as well as nonpathogenic strains of C. flaccumfaciens is warranted for a better understanding of the diversity within this phytopathogenic bacterium
Enhancement of hadron–electron discrimination in calorimeters by detection of the neutron component
In many physics experiments where calorimeters are employed, the requirement of an accurate energy measurement is accompanied by the requirement of very high hadronelectron discrimination power. Normally the latter requirement is achieved by designing a high-granularity detector with sufficient depth so that the showers can fully develop. This method has many drawbacks ranging from the high number of electronic channels to the high mass of the detector itself. Some of these drawbacks may in fact severely limit the deployment of such a detector in many experiments, most notably in space-based ones. Another method, proposed by our group and currently under investigation, relies on the use of scintillation detectors which are sensitive to the neutron component of the hadron showers. Here a review of the current status will be presented starting with the simulations performed both with GEANT4 and FLUKA. A small prototype detector has been built and has been tested in a high-energy pion/electron beam behind a "shallow" calorimeter. Results are encouraging and indicate that it is possible to enhance the discrimination power of an existing calorimeter by the addition of a small-mass neutron detector, thus paving the way for better performing astroparticle experiments. © 2010 Elsevier B.V. All rights reserved
On line power spectra identification and whitening for the noise in interferometric gravitational wave detectors
In this paper we address both to the problem of identifying the noise Power
Spectral Density of interferometric detectors by parametric techniques and to
the problem of the whitening procedure of the sequence of data. We will
concentrate the study on a Power Spectral Density like the one of the
Italian-French detector VIRGO and we show that with a reasonable finite number
of parameters we succeed in modeling a spectrum like the theoretical one of
VIRGO, reproducing all its features. We propose also the use of adaptive
techniques to identify and to whiten on line the data of interferometric
detectors. We analyze the behavior of the adaptive techniques in the field of
stochastic gradient and in the
Least Squares ones.Comment: 28 pages, 21 figures, uses iopart.cls accepted for pubblication on
Classical and Quantum Gravit
Noise parametric identification and whitening for LIGO 40-meter interferometer data
We report the analysis we made on data taken by Caltech 40-meter prototype
interferometer to identify the noise power spectral density and to whiten the
sequence of noise. We concentrate our study on data taken in November 1994, in
particular we analyzed two frames of data: the 18nov94.2.frame and the
19nov94.2.frame.
We show that it is possible to whiten these data, to a good degree of
whiteness, using a high order whitening filter. Moreover we can choose to
whiten only restricted band of frequencies around the region we are interested
in, obtaining a higher level of whiteness.Comment: 11 pages, 15 figures, accepted for publication by Physical Review
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