1,255 research outputs found
Structure of Madrid basin (NE zone) derived from gravity data
[Abstract] Modelling of five profiles in the NE area of Madrid Basin shows that low anomalies are related to both the thicker sediments infill of the Basin and the
basement rocks like gneiss and granites. The highs are related to thick sequences
ofalternating slates and quarzites, outcropping or underlaying a thin cover. The
main gradients are related to the marginal faults of the Basin. The existence of
a granitic body and a NE-SW striking fault, was also detected. Out of the data
obtained in the models, an isobaths map has been depicted of Madrid Basin which shows a fault bounded structure
Fast ferrous heme-NO oxidation in nitric oxide synthases.
International audienceDuring catalysis, the heme in nitric oxide synthase (NOS) binds NO before releasing it to the environment. Oxidation of the NOS ferrous heme-NO complex by O2 is key for catalytic cycling, but the mechanism is unclear. We utilized stopped-flow methods to study the reaction of O2 with ferrous heme-NO complexes of inducible and neuronal NOS enzymes. We found that the reaction does not involve heme-NO dissociation, but instead proceeds by a rapid direct reaction of O2 with the ferrous heme-NO complex. This behavior is novel and may distinguish heme-thiolate enzymes, such as NOS, from related heme proteins
Stability of the hard-sphere icosahedral quasilattice
The stability of the hard-sphere icosahedral quasilattice is analyzed using
the differential formulation of the generalized effective liquid approximation.
We find that the icosahedral quasilattice is metastable with respect to the
hard-sphere crystal structures. Our results agree with recent findings by
McCarley and Ashcroft [Phys. Rev. B {\bf 49}, 15600 (1994)] carried out using
the modified weighted density approximation.Comment: 15 pages, 2 figures available from authors upon request, (revtex),
submitted to Phys. Rev.
Coherent and non-coherent processing of multiband radar sensor data
Increasing resolution is an attractive goal for all types of radar sensor applications. Obtaining high radar resolution is strongly related to the signal bandwidth which can be used. The currently available frequency bands however, restrict the available bandwidth and consequently the achievable range resolution. As nowadays more sensors become available e.g. on automotive platforms, methods of combining sensor information stemming from sensors operating in different and not necessarily overlapping frequency bands are of concern. It will be shown that it is possible to derive benefit from perceiving the same radar scenery with two or more sensors in distinct frequency bands. Beyond ordinary sensor fusion methods, radar information can be combined more effectively if one compensates for the lack of mutual coherence, thus taking advantage of phase information. <P> At high frequencies, complex scatterers can be approximately modeled as a group of single scattering centers with constant delay and slowly varying amplitude, i.e. a set of complex exponentials buried in noise. The eigenanalysis algorithms are well known for their capability to better resolve complex exponentials as compared to the classical spectral analysis methods. These methods exploit the statistical properties of those signals to estimate their frequencies. Here, two main approaches to extend the statistical analysis for the case of data collected at two different subbands are presented. One method relies on the use of the band gap information (and therefore, coherent data collection is needed) and achieves an increased resolution capability compared with the single-band case. On the other hand, the second approach does not use the band gap information and represents a robust way to process radar data collected with incoherent sensors. Combining the information obtained with these two approaches a robust estimator of the target locations with increased resolution can be built
Open charm meson in nuclear matter at finite temperature beyond the zero range approximation
The properties of open charm mesons, , , and in
nuclear matter at finite temperature are studied within a self-consistent
coupled-channel approach. The interaction of the low lying pseudoscalar mesons
with the ground state baryons in the charm sector is derived from a -channel
vector-exchange model. The in-medium scattering amplitudes are obtained by
solving the Lippmann-Schwinger equation at finite temperature including Pauli
blocking effects, as well as , , and self-energies
taking their mutual influence into account. We find that the in-medium
properties of the meson are affected by the -meson self-energy through
the intermediate loops coupled to states. Similarly, dressing the
meson in the loops has an influence over the properties of
the meson.Comment: 23 pages, 9 figures, 2 table
Étale Covers and Fundamental Groups of Schematic Finite Spaces
[EN] We introduce the category of finite étale covers of an arbitraryschematic space X and show that, equipped with an appropriate naturalfiber functor, it is a Galois Category. This allows us to define the étale
fundamental group of schematic spaces. If X is a finite model of a schemeS, we show that the resulting Galois theory on X coincides with theclassical theory of finite étale covers on S, and therefore, we recover
the classical étale fundamental group introduced by Grothendieck. Toprove these results, it is crucial to find a suitable geometric notion ofconnectedness for schematic spaces and also to study their geometric
points. We achieve these goals by means of the strong cohomologicalconstraints enjoyed by schematic spaces.Publicación en abierto financiada por el Consorcio de Bibliotecas Universitarias de Castilla y León (BUCLE), con cargo al Programa Operativo 2014ES16RFOP009 FEDER 2014-2020 DE CASTILLA Y LEÓN, Actuación:20007-CL - Apoyo Consorcio BUCLE
- …