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Search Results: 1 - 10 of 544919 matches for " M. C. Mora Espí "
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Realtime calibration of the A4 electromagnetic lead fluoride calorimeter
S. Baunack,D. Balaguer Ríos,L. Capozza,J. Diefenbach,R. Frascaria,B. Gl?ser,D. v. Harrach,Y. Imai,R. Kothe,R. Kunne,J. H. Lee,F. E. Maas,M. C. Mora Espí,M. Morlet,S. Ong,E. Schilling,J. van de Wiele,C. Weinrich
Physics , 2011, DOI: 10.1016/j.nima.2011.02.099
Abstract: Sufficient energy resolution is the key issue for the calorimetry in particle and nuclear physics. The calorimeter of the A4 parity violation experiment at MAMI is a segmented calorimeter where the energy of an event is determined by summing the signals of neighbouring channels. In this case the precise matching of the individual modules is crucial to obtain a good energy resolution. We have developped a calibration procedure for our total absorbing electromagnetic calorimeter which consists of 1022 lead fluoride (PbF_2) crystals. This procedure reconstructs the the single-module contributions to the events by solving a linear system of equations, involving the inversion of a 1022 x 1022-matrix. The system has shown its functionality at beam energies between 300 and 1500 MeV and represents a new and fast method to keep the calorimeter permanently in a well-calibrated state.
Class of PPT bound entangled states associated to almost any set of pure entangled states
M. Piani,C. Mora
Physics , 2006, DOI: 10.1103/PhysRevA.75.012305
Abstract: We analyze a class of entangled states for bipartite $d \otimes d$ systems, with $d$ non-prime. The entanglement of such states is revealed by the construction of canonically associated entanglement witnesses. The structure of the states is very simple and similar to the one of isotropic states: they are a mixture of a separable and a pure entangled state whose supports are orthogonal. Despite such simple structure, in an opportune interval of the mixing parameter their entanglement is not revealed by partial transposition nor by the realignment criterion, i.e. by any permutational criterion in the bipartite setting. In the range in which the states are Positive under Partial Transposition (PPT), they are not distillable; on the other hand, the states in the considered class are provably distillable as soon as they are Nonpositive under Partial Transposition (NPT). The states are associated to any set of more than two pure states. The analysis is extended to the multipartite setting. By an opportune selection of the set of multipartite pure states, it is possible to construct mixed states which are PPT with respect to any choice of bipartite cuts and nevertheless exhibit genuine multipartite entanglement. Finally, we show that every $k$-positive but not completely positive map is associated to a family of nondecomposable maps.
Measurement of Strange Quark Contributions to the Vector Form Factors of the Proton at Q**2=0.22 (GeV/c)**2
S. Baunack,K. Aulenbacher,D. Balaguer Ríos,L. Capozza,J. Diefenbach,B. Gl?ser,D. v. Harrach,Y. Imai,E. M. Kabu?,R. Kothe,J. H. Lee,H. Merkel,M. C. Mora Espí,U. Müller,E. Schilling,G. Stephan,C. Weinrich,J. Arvieux,M. A. El-Yakoubi,R. Kunne,F. E. Maas,M. Morlet,S. Ong,J. van de Wiele,S. Kowalski,Y. Prok,S. Taylor
Physics , 2009, DOI: 10.1103/PhysRevLett.102.151803
Abstract: A new measurement of the parity violating asymmetry in elastic electron scattering on hydrogen at backward angles and at a four momentum transfer of Q^2=0.22 (GeV/c)^2 is reported here. The measured asymmetry is A_LR=(-17.23 +- 0.82_stat +-0.89_syst) ppm. The Standard Model prediction assuming no strangeness is A_0=(-15.87 +- 1.22) ppm. In combination with previous results from measurements at forward angles, it it possible to disentangle for the first time the strange electric and magnetic form factors at this momentum transfer, G_E^s(0.22)=0.050 +- 0.038 +- 0.019 and G_M^s(0.22)=-0.14 +- 0.11 +- 0.11.
La Investigación orientada en el nivel superior para la ense anza del campo eléctrico
M. Sandoval,César Mora
Latin-American Journal of Physics Education , 2011,
Abstract: We show a work using oriented research as teaching strategy to electric field concept in freshmen. The results showsthat (in experimental group) pre-conceptual models among students of high and low academic level tend to be very similar in activities that involve conceptual reasoning; however on activities more abstract the difference among them are remark. We found also that gain in experimental group was 11% compared with 3.8% of control group.
Modelos erróneos sobre la comprensión del campo eléctrico en estudiantes universitarios
M. Sandoval,César Mora
Latin-American Journal of Physics Education , 2009,
Abstract: We show results of research about misconceptions, in university students, about electric field concepts and itsinfluence among electric charges and electric energy conservation. Exhibit a didactic proposal based on history sciencein order to improve this topic in those students; this proposed rest in a technical socio-constructivist called Jigsaw,primarily history of charges concept and history of lines force. We show some advantage over traditional teaching, wecan observe a better attitude among students in experimental group at moment of solve problem and study history text,so there is little grow in score of post test compared with control group.
Natural Contaminants in Drinking Waters (Arsenic, Boron, Fluorine and Vanadium) in the Southern Pampean Plain, Argentina  [PDF]
Martín E. Espósito, Juan D. Paoloni, Mario E. Sequeira, Nilda M. Amiotti, María del C. Blanco
Journal of Environmental Protection (JEP) , 2011, DOI: 10.4236/jep.2011.21011
Abstract: This research aims at making a diagnosis of the presence of arsenic, boron, fluorine and vanadium in the waters from the basin of El Divisorio stream, tributary of Paso de las Piedras reservoir, in the southwest of Buenos Aires Province. This storage is used to provide water to the cities of Bahía Blanca and Punta Alta with a population of approximately 400,000 inhabitants. A selective and specific sampling of wells, perforations and superficial watercourses was made in 46 points, in an area of nearly 400 km2. Groundwaters had arsenic (max. 0.114 mg/l) exceeding the reference guideline in 97.3% of the samples, boron (max. 1.42 mg/l), vanadium (max. 0.8 mg/l) and fluorine (max. 6.6 mg/l), being respect- tively, 91.9%, 82.9%, and 67.6%. Regarding the superficial flow, while arsenic concentrations were higher than the limit in 100% of the cases (max. 0.072 mg/l), 88.9% corresponded to elevated boron (max. 1 mg/l) and vanadium (max. 0.23 mg/l) and only 22.2% to fluorine (max. 3.18 mg/l) ones. In all these cases, concentrations exceed the reference guideline values suggested by the World Health Organization, the Argentine Food Code and the Environmental Protec- tion Agency. The presence of these contaminants that finally could determine the quality of the water resource entering the reservoir is attributed to the natural characteristics of the environment since contributions by anthropic actions have not been detected in the area. The most critical sectors in the basin were identified in order to stress the possible negative influence of consuming these waters on the community’s health, with the purpose of reporting the results to institutions, authorities and the population and applying them to preventive medicine.
Acerca del cáncer cervicouterino como un importante problema de salud pública About uterocervical cancer as an important public health problem
Julio César Espín Falcón,Adriana Cardona Almeida,Yuxini Acosta Gómez,Mariela Valdés Mora
Revista Cubana de Medicina General Integral , 2012,
Abstract: El cáncer se presenta como un importante problema de salud, dada la alta morbilidad y mortalidad que produce. Es uno de los procesos más complejos de la naturaleza y resulta el más complicado en la esfera de la medicina por su origen multicausal, la complejidad de sus mecanismos patogénicos y la variedad de formas y tipos que pueden originarse en el ser vivo. El objetivo de este trabajo es ofrecer información útil y actualizada acerca del cáncer cervicouterino. Esta enfermedad es prevenible y curable y se relaciona con la aparición del cáncer en vagina, cuello uterino, vulva y ano; en las mujeres se ha demostrado que la infección por el virus del papiloma humano es un factor de riesgo para su desarrollo. En la actualidad existen y se comercializan en el mundo dos tipos de vacuna, lo que se considera uno de los mayores avances en la medicina preventiva moderna. La aplicación de estas vacunas profilácticas contra el virus del papiloma humano podría reducir la incidencia y mortalidad por cáncer cervicouterino. Esta enfermedad constituye una de las entidades con más impacto y repercusión sobre la salud femenina, particularmente en las mujeres jóvenes. Está considerada una enfermedad emergente desde hace escasos a os y sus consecuencias sociales, humanas y económicas lo convierten en un problema importante de salud pública y de la humanidad. Cancer represents an important health problem due to its high morbidity and mortality. It is one of the most complex processes of nature and the most complicated in medicine because of its multiple cause origin, the complexity of its pathogenic mechanisms and the variety of forms and types that may adopt in the subject alive. The objective of this paper was to provide useful and updated information on the uterocervical cancer. This disease is preventable and curable; it is related to the occurrence of cancer in the vagina, the uterine neck, the vulva and the anus. It has been proved that human papiloma virus infection is one of the risk factor for cancer in females. Two kinds of vaccine are marketed worldwide, and this is considered as one of the major advances in the modern preventive medicine. The administration of these prophylactic vaccines against the human papiloma could reduce the incidence and the mortality cause by uterocervical cancer, one of the diseases with high impact and repercussion on the female health, particularly in young females. It is considered an emerging disease and its human, social and economic consequences turn it into an important public health problem for mankind.
A weak Local Linearization scheme for stochastic differential equations with multiplicative noise
J. C. Jimenez,C. Mora,M. Selva
Mathematics , 2015,
Abstract: In this paper, a weak Local Linearization scheme for Stochastic Differential Equations (SDEs) with multiplicative noise is introduced. First, for a time discretization, the solution of the SDE is locally approximated by the solution of the piecewise linear SDE that results from the Local Linearization strategy. The weak numerical scheme is then defined as a sequence of random vectors whose first moments coincide with those of the piecewise linear SDE on the time discretization. The rate of convergence is derived and numerical simulations are presented for illustrating the performance of the scheme.
Nordhaus-Gaddum bounds for locating domination
C. Hernando,M. Mora,I. M. Pelayo
Mathematics , 2012,
Abstract: A dominating set S of graph G is called metric-locating-dominating if it is also locating, that is, if every vertex v is uniquely determined by its vector of distances to the vertices in S. If moreover, every vertex v not in S is also uniquely determined by the set of neighbors of v belonging to S, then it is said to be locating-dominating. Locating, metric-locating-dominating and locating-dominating sets of minimum cardinality are called b-codes, e-codes and l-codes, respectively. A Nordhaus-Gaddum bound is a tight lower or upper bound on the sum or product of a parameter of a graph G and its complement G. In this paper, we present some Nordhaus-Gaddum bounds for the location number b, the metric-location-number e and the location-domination number l. Moreover, in each case, the graph family attaining the corresponding bound is characterized.
On global location-domination in graphs
C. Hernando,M. Mora,I. M. Pelayo
Mathematics , 2013,
Abstract: A dominating set $S$ of a graph $G$ is called locating-dominating, LD-set for short, if every vertex $v$ not in $S$ is uniquely determined by the set of neighbors of $v$ belonging to $S$. Locating-dominating sets of minimum cardinality are called $LD$-codes and the cardinality of an LD-code is the location-domination number $\lambda(G)$. An LD-set $S$ of a graph $G$ is global if it is an LD-set of both $G$ and its complement $\overline{G}$. The global location-domination number $\lambda_g(G)$ is the minimum cardinality of a global LD-set of $G$. In this work, we give some relations between locating-dominating sets and the location-domination number in a graph and its complement.
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