2,274 research outputs found
The Monge problem in Wiener Space
We address the Monge problem in the abstract Wiener space and we give an
existence result provided both marginal measures are absolutely continuous with
respect to the infinite dimensional Gaussian measure {\gamma}
Uncertainties in Atmospheric Neutrino Fluxes
An evaluation of the principal uncertainties in the computation of neutrino
fluxes produced in cosmic ray showers in the atmosphere is presented. The
neutrino flux predictions are needed for comparison with experiment to perform
neutrino oscillation studies. The paper concentrates on the main limitations
which are due to hadron production uncertainties. It also treats primary cosmic
ray flux uncertainties, which are at a lower level. The absolute neutrino
fluxes are found to have errors of around 15% in the neutrino energy region
important for contained events underground. Large cancellations of these errors
occur when ratios of fluxes are considered, in particular, the
ratio below GeV, the
ratio below GeV and
the up/down ratios above GeV are at the 1% level. A detailed
breakdown of the origin of these errors and cancellations is presented.Comment: 14 pages, 22 postscript figures, written in Revte
Search for nuclearites with the SLIM detector
We discuss the properties of cosmic ray nuclearites, from the point of view
of their search with large nuclear track detector arrays exposed at different
altitudes, in particular with the SLIM experiment at the Chacaltaya high
altitude lab (5290 m a.s.l.). We present calculations concerning their
propagation in the Earth atmosphere and discuss their possible detection with
CR39 and Makrofol nuclear track detectors.Comment: 11 pages, 6 figure
Calculus and heat flow in metric measure spaces and applications to spaces with Ricci bounds from below
This paper is devoted to a deeper understanding of the heat flow and to the
refinement of calculus tools on metric measure spaces (X,d,m). Our main results
are:
- A general study of the relations between the Hopf-Lax semigroup and
Hamilton-Jacobi equation in metric spaces (X,d).
- The equivalence of the heat flow in L^2(X,m) generated by a suitable
Dirichlet energy and the Wasserstein gradient flow of the relative entropy
functional in the space of probability measures P(X).
- The proof of density in energy of Lipschitz functions in the Sobolev space
W^{1,2}(X,d,m).
- A fine and very general analysis of the differentiability properties of a
large class of Kantorovich potentials, in connection with the optimal transport
problem.
Our results apply in particular to spaces satisfying Ricci curvature bounds
in the sense of Lott & Villani [30] and Sturm [39,40], and require neither the
doubling property nor the validity of the local Poincar\'e inequality.Comment: Minor typos corrected and many small improvements added. Lemma 2.4,
Lemma 2.10, Prop. 5.7, Rem. 5.8, Thm. 6.3 added. Rem. 4.7, Prop. 4.8, Prop.
4.15 and Thm 4.16 augmented/reenforced. Proof of Thm. 4.16 and Lemma 9.6
simplified. Thm. 8.6 corrected. A simpler axiomatization of weak gradients,
still equivalent to all other ones, has been propose
New records of Pteridophytes in the semi-arid region of Brazil.
The goal of this paper is to enumerate the pteridophytes that occur in the semi-árid region of the State of Pernambuco, Brazil
Interaction between sucrose and pH during in vitro culture of Nephrolepis biserrata (Sw.) Schott (Pteridophyta).
Interaction between sucrose and pH during in vitro culture of Nephrolepis biserrata (Sw.) Schott (Pteridophyta)). The present work reports the effect of different pH and sucrose concentrations on in vitro propagation of Nephrolepis biserrata. Fronds aseptically obtained from stolon segment culture were cultivated in MS semi-solid medium supplemented with 0, 15, 30, 45 and 60 g.L -1 sucrose and pH adjusted to 3, 5, 7 and 9, in a factorial design. Frond number and length, pinnae number, raquis length and diam eter, fresh and dry matter weight were measured. Inhibition of shoot and leaf regeneration was observed in all the pH treatments in the abs ence of sucrose. On the other hand, when sucrose was added to the medium, the shoot number increased, reaching the maximum average values of 51.25 and 38.25 shoot per explant at pH 5 and 7, respectively. Sucrose concentrations from 15 to 45g.L -1 increased leaf length and diameter and the pH 9 did not affect the dry matter weight, and was still not adequate for development of new fronds. Young sporophytes were successfully acclimated
Time correlations of high energy muons in an underground detector
We present the result of a search for correlations in the arrival times of
high energy muons collected from 1995 till 2000 with the streamer tube system
of the complete MACRO detector at the underground Gran Sasso Lab. Large samples
of single muons (8.6 million), double muons (0.46 million) and multiple muons
with multiplicities from 3 to 6 (0.08 million) were selected. These samples
were used to search for time correlations of cosmic ray particles coming from
the whole upper hemisphere or from selected space cones. The results of our
analyses confirm with high statistics a random arrival time distribution of
high energy cosmic rays.Comment: (12 pages, 7 figures, Accepted for publication in Astroparticle
Physics
SBV Regularity for Genuinely Nonlinear, Strictly Hyperbolic Systems of Conservation Laws in one space dimension
We prove that if is the entropy
solution to a strictly hyperbolic system of conservation laws with
genuinely nonlinear characteristic fields then up to a
countable set of times the function is in
, i.e. its distributional derivative is a measure with no
Cantorian part.
The proof is based on the decomposition of into waves belonging to
the characteristic families and the balance
of the continuous/jump part of the measures in regions bounded by
characteristics. To this aim, a new interaction measure \mu_{i,\jump} is
introduced, controlling the creation of atoms in the measure .
The main argument of the proof is that for all where the Cantorian part
of is not 0, either the Glimm functional has a downward jump, or there is
a cancellation of waves or the measure is positive
CPT-violating neutrino oscillations
We propose a simple phenomenological model predicting, through Lorentz
symmetry breaking, a CPT-violating asymmetry between particle and antiparticle
states in neutrino oscillations involving sterile neutrinos. Such a model is
able to explain the apparently observed anomalous excess of low-energy
\nu_e-like events, reported by the MiniBooNE collaboration, as well as the
non-observation of the corresponding anomalous excess of \ov{\nu}_e-like
events. The present model leads to very specific physical predictions in the
neutrino oscillations scenario, and account for the observed anomalies in terms
of only one CPT-Lorentz violation parameter of the order of the
Grand-Unification energy scale.Comment: revtex, 4 pages, no figure
Puerperal Complications Following Elective Cesarean Sections for Twin Pregnancies
OBJECTIVE:
To estimate the maternal puerperal morbidity in elective and emergent cesareans in twins.
STUDY DESIGN:
We evaluated postpartum complications among patients who underwent elective cesarean birth for twin pregnancy. This group was compared to matched singletons and to emergent cesareans in twins.
RESULTS:
During the period September 1994-March 2006 there were 299 (47.4%) elective and 80 (12.7%) emergent cesarean sections in twin pregnancies, for a total of 379 (60.1%) cesarean births for both twins. Controls included 299 cases of elective cesareans in singletons. The comparison between elective and emergent cesareans and between elective cesareans in twins and in singletons found no significant differences in postpartum fever, scar infection, and postpartum hemorrhage. Venous thromboembolism occurred in two twin pregnancies, one in the elective and one in the emergent cesarean group. Postpartum hysterectomy was required in a singleton pregnancy following an elective cesarean birth.
CONCLUSION:
At present, no data exist to show a disadvantage for a planned cesarean birth for twins.info:eu-repo/semantics/publishedVersio
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