1,990 research outputs found
Comment on "Theory of tailoring sonic devices: Diffraction dominates over refraction"
Recently N. Garcia et al. (Phys. Rev. E 67, 046606 (2003)) theoretically
studied several acoustic devices with dimensions on de order of several
wavelenghts. The authors discussed on experimental results previously reported
by several of us (F. Cervera et al., Phys. Rev. Lett. 88, 023902 (2002)). They
concluded that diffraction and not refraction is the ominating mechanism that
explain the focusing effects observed in those experiments. In this Comment we
reexamined their calculations and discussed why some of their interpretations
of our results are misleading.Comment: 2 pages, 2 figures, a comment on an articl
The recent uvigerinids (benthic foraminifera) in the northeastern Gulf of Cadiz
The distributional patterns and related environmental parameters for nine Uvigerina (benthic foraminifera) species occurring in the northeast Gulf of Cadiz are discussed. A new species (Uvigerina pusilla n. sp.) is described. Two assemblages (F1: Uvigerina peregrina and F2: Rectuvigerina phlegeri) are characteristic of the distribution of uvigerinids in this region, related to bathymetry and the mud-sand substrate in North Atlantic Superficial and Central water.Se ha determinado el área de distribución de los uvigerínidos (foraminíferos bentónicos) en el noreste del golfo de Cádiz, donde se han encontrado nueve especies. Su distribución está relacionada con las características texturales y geoquímicas del sedimento. Se ha descrito una especie nueva (Uvigerina pusilla nov. es.). Mediante análisis factorial y regresión multilineal se han diferenciado dos asociaciones, F1 (Uvigerina peregrina) y F2 (Rectuvigerina phlegeri) relacionadas con las características batimétricas y geoquímicas del medio, en la zona de influencia del agua superficial y central noratlántica.Instituto Español de Oceanografí
Toward CP-even Neutrino Beam
The best method of measuring CP violating effect in neutrino oscillation
experiments is to construct and use a neutrino beam made of an ideal mixture of
and of monochromatic lines. The conceptual design of such
a beam is described, together with how to measure the CP-odd quantity. We
propose to exploit an accelerated unstable hydrogen-like heavy ion in a storage
ring, whose decay has both electron capture and bound beta decay with a
comparable fraction.Comment: 6 pages, 2 figures, Published versio
First record of Calma gobioophaga Calado and Urgorri, 2002 (Gastropoda: Nudibranchia) in the Mediterranean Sea
Specimens of the nudibranch genus Calma were observed under stones at two Croatian localities while feeding on gobiid eggs. Some ambiguous morphological features compared with the original descriptions of the known species of the genus, C. glaucoides and C. gobioophaga, hampered an easy identification. Genetic data (COI and 16S sequences) confirmed the distinction between the two species of the genus Calma, and allowed to unambiguously identify the Croatian specimens as Calma gobioophaga. This is the first record of this species for the Mediterranean and extends remarkably its distribution range. Finally, the eggs fed by the Croatian specimens have been taxonomically identified by using the 12S rDNA marker as Gobius cobitis
First record of Calma gobioophaga Calado and Urgorri, 2002 (Gastropoda: Nudibranchia)in the Mediterranean sea
Specimens of the nudibranch genus Calma were observed under boulders at two Croatian localities while feeding on gobiid eggs. Some ambiguous morphological features compared with the original descriptions of the known species of the genus, C. glaucoides and C. gobioophaga hampered easy identification. Genetic data (COI and 16S sequences) confirmed the distinction between the two species of the genus Calma, and allowed unambiguous identification of the Croatian specimens as Calma gobioophaga. This is the first record of this species for the Mediterranean and extends its distribution range remarkably. Finally, the eggs consumed by the Croatian C. gobioophaga specimens have been taxonomically identified by using the 12S rDNA marker as Gobius cobitis
First record of Calma gobioophaga Calado and Urgorri, 2002 (Gastropoda: Nudibranchia) in the Mediterranean Sea
Specimens of the nudibranch genus Calma were observed under stones at two Croatian localities while feeding on gobiid eggs. Some ambiguous morphological features compared with the original descriptions of the known species of the genus, C. glaucoides and C. gobioophaga, hampered an easy identification. Genetic data (COI and 16S sequences) confirmed the distinction between the two species of the genus Calma, and allowed to unambiguously identify the Croatian specimens as Calma gobioophaga. This is the first record of this species for the Mediterranean and extends remarkably its distribution range. Finally, the eggs fed by the Croatian specimens have been taxonomically identified by using the 12S rDNA marker as Gobius cobitis
Determining Neutrino Mass Hierarchy by Precision Measurements in Electron and Muon Neutrino Disappearance Experiments
Recently a new method for determining the neutrino mass hierarchy by
comparing the effective values of the atmospheric \Delta m^2 measured in the
electron neutrino disappearance channel, \Delta m^2(ee), with the one measured
in the muon neutrino disappearance channel, \Delta m^2(\mu \mu), was proposed.
If \Delta m^2(ee) is larger (smaller) than \Delta m^2(\mu \mu) the hierarchy is
of the normal (inverted) type. We re-examine this proposition in the light of
two very high precision measurements: \Delta m^2(\mu \mu) that may be
accomplished by the phase II of the Tokai-to-Kamioka (T2K) experiment, for
example, and \Delta m^2(ee) that can be envisaged using the novel Mossbauer
enhanced resonant \bar\nu_e absorption technique. Under optimistic assumptions
for the systematic uncertainties of both measurements, we estimate the
parameter region of (\theta_13, \delta) in which the mass hierarchy can be
determined. If \theta_13 is relatively large, sin^2 2\theta_13 \gsim 0.05, and
both of \Delta m^2(ee) and \Delta m^2(\mu \mu) can be measured with the
precision of \sim 0.5 % it is possible to determine the neutrino mass hierarchy
at > 95% CL for 0.3 \pi \lsim \delta \lsim 1.7 \pi for the current best fit
values of all the other oscillation parameters.Comment: 12 pages, 6 postscript figure
Characterization of genetic variation within table grape varieties (Vitis vinifera L.) based on AFLP markers
AFLPs were used to characterize a collection of 35 table grape varieties. A single AFLP reaction with a single combination of selective primers yielded an average of 50 polymorphic and scorable amplified bands in this collection and was enough to unequivocally identify each analyzed variety, Genetic similarity between different varieties was estimated, based on the results obtained with two primer combinations, to be between 0.65 and 0.90, while sibling varieties derived from the same cross showed a genetic similarity higher than 0.80, The analysis of several samples belonging to the same varieties, yet from different origins, showed stability of the AFLP patterns as to unequivocally and reproducibly identify them. Furthermore, some specific primer combinations detected a low level of variation that could be due to somatic variation and would be useful in clonal identification
Analytic Approximations for Three Neutrino Oscillation Parameters and Probabilities in Matter
The corrections to neutrino mixing parameters in the presence of matter of
constant density are calculated systematically as series expansions in terms of
the mass hierarchy \dm{21}/\dm{31}. The parameter mapping obtained is then
used to find simple, but nevertheless accurate formulas for oscillation
probabibilities in matter including CP-effects. Expressions with one to one
correspondence to the vacuum case are derived, which are valid for neutrino
energies above the solar resonance energy. Two applications are given to show
that these results are a useful and powerful tool for analytical studies of
neutrino beams passing through the Earth mantle or core: First, the
``disentanglement problem'' of matter and CP-effects in the CP-asymmetry is
discussed and second, estimations of the statistical sensitivity to the
CP-terms of the oscillation probabilities in neutrino factory experiments are
presented.Comment: 17 pages, 3 figure
Necrosis aséptica de astrágalo: presentación de un caso en la infancia
Se presenta un caso de necrosis aséptica de astrágalo en la infancia de origen
idiopático que, hasta donde sabemos, resulta único en la literatura mundial. Se trata
de una niña con un síndrome de Klippel-Trenaunay que debuta a la edad de 8 años con
un cuadro de dolor e inflamación intermitente en tobillo derecho. Se realiza estudio mediante
radiografías simples, RNM y gammagrafía con "Tc, llegando al diagnóstico de necrosis
avascular de astrágalo. Se trata mediante descarga del miembro durante 3 meses,
realizando la paciente vida normal con mínimas molestias a los 3 años del diagnósticoWe present one case of idiopathic avascular necrosis of the talus in a child.To our knowledge, this is the first case reported in the literature. The patient is a girl diagnosed of Klippel-Trenaunay syndrome of the ipsilateral limb. When she was 8 years old began with pain and swelling in the right ankle. Simple X-ray, isotopic bone scan and MRI were done, and she was diagnosed of avascular necrosis of the talar dome. The treatment was no weight bearing for three months. She has no sympthoms three years after diagnosis
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