901 research outputs found
Quantifying entanglement in multipartite conditional states of open quantum systems by measurements of their photonic environment
A key lesson of the decoherence program is that information flowing out from
an open system is stored in the quantum state of the surroundings.
Simultaneously, quantum measurement theory shows that the evolution of any open
system when its environment is measured is nonlinear and leads to pure states
conditioned on the measurement record. Here we report the discovery of a
fundamental relation between measurement and entanglement which is
characteristic of this scenario. It takes the form of a scaling law between the
amount of entanglement in the conditional state of the system and the
probabilities of the experimental outcomes obtained from measuring the state of
the environment. Using the scaling, we construct the distribution of
entanglement over the ensemble of experimental outcomes for standard models
with one open channel and provide rigorous results on finite-time
disentanglement in systems coupled to non-Markovian baths. The scaling allows
the direct experimental detection and quantification of entanglement in
conditional states of a large class of open systems by quantum tomography of
the bath.Comment: 12 pages (including supplementary information), 4 figure
Same Difference: How Gender Myths Are Hurting Our Relationships, Our Children, and Our Jobs, by Rosalind Barnett & Caryl Rivers
Ontology-Based Data Access and Integration
An ontology-based data integration (OBDI) system is an information management system consisting of three components: an ontology, a set of data sources, and the mapping between the two. The ontology is a conceptual, formal description of the domain of interest to a given organization (or a community of users), expressed in terms of relevant concepts, attributes of concepts, relationships between concepts, and logical assertions characterizing the domain knowledge. The data sources are the repositories accessible by the organization where data concerning the domain are stored. In the general case, such repositories are numerous, heterogeneous, each one managed and maintained independently from the others. The mapping is a precise specification of the correspondence between the data contained in the data sources and the elements of the ontology. The main purpose of an OBDI system is to allow information consumers to query the data using the elements in the ontology as predicates.
In the special case where the organization manages a single data source, the term ontology-based data access (ODBA) system is used
On the succinctness of query rewriting over shallow ontologies
We investigate the succinctness problem for conjunctive query rewritings over OWL2QL ontologies of depth 1 and 2 by means of hypergraph programs computing Boolean functions. Both positive and negative results are obtained. We show that, over ontologies of depth 1, conjunctive queries have polynomial-size nonrecursive datalog rewritings; tree-shaped queries have polynomial positive existential rewritings; however, in the worst case, positive existential rewritings can be superpolynomial. Over ontologies of depth 2, positive existential and nonrecursive datalog rewritings of conjunctive queries can suffer an exponential blowup, while first-order rewritings can be superpolynomial unless NP ïżœis included in P/poly. We also analyse rewritings of tree-shaped queries over arbitrary ontologies and note that query entailment for such queries is fixed-parameter tractable
Quantum Conductance Steps in Solutions of Multiwalled Carbon Nanotubes
We have prepared solutions of multiwalled carbon nanotubes in Aroclor 1254, a
mixture of polychlorinated biphenyls. The solutions are stable at room
temperature. Transport measurements were performed using a scanning--tunneling
probe on a sample prepared by spin--coating of the solution on gold substrates.
Conductance steps were clearly seen. An histogram of a high number of traces
shows maximum peaks at integer values of the conductance quantum , demonstrating ballistic transport at room temperature along the carbon
nanotube over distances longer than .Comment: 4 pages and 2 figure
Analysis of Turkish swordfish (Xiphias gladius) catch rates in the eastern Mediterranean
Indices of abundance of swordfish (Xiphias gladius) from the Turkish gillnet and longline
fisheries operating in the eastern Mediterranean are presented for the period 2008-2013.
Annual standardized indices were estimated by means of Generalized Linear Modeling
techniques and the predictor variables included the Year and, Month of sampling. Gillnet
CPUE data suggested the presence of and increasing abundance trend over the period 2008-
2010, while not any particular trend was identified from the analysis of the longline data set.VersiĂłn del edito
Contribution of microscopy for understanding the mechanism of action against trypanosomatids
Transmission electron microscopy (TEM) has proved to be a useful tool to study the ultrastructural alterations and the target organelles of new antitrypanosomatid drugs. Thus, it has been observed that sesquiterpene lactones induce diverse ultrastructural alterations in both T. cruzi and Leishmania spp., such as cytoplasmic vacuolization, appearance of multilamellar structures, condensation of nuclear DNA, and, in some cases, an important accumulation of lipid vacuoles. This accumulation could be related to apoptotic events. Some of the sesquiterpene lactones (e.g., psilostachyin) have also been demonstrated to cause an intense mitochondrial swelling accompanied by a visible kinetoplast deformation as well as the appearance of multivesicular bodies. This mitochondrial swelling could be related to the generation of oxidative stress and associated to alterations in the ergosterol metabolism. The appearance of multilamellar structures and multiple kinetoplasts and flagella induced by the sesquiterpene lactone psilostachyin C indicates that this compound would act at the parasite cell cycle level, in an intermediate stage between kinetoplast segregation and nuclear division. In turn, the diterpene lactone icetexane has proved to induce the external membrane budding on T. cruzi together with an apparent disorganization of the pericellar cytoskeleton. Thus, ultrastructural TEM studies allow elucidating the possible mechanisms and the subsequent identification of molecular targets for the action of natural compounds on trypanosomatids.Fil: Lozano, Esteban SebastiĂĄn. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico Conicet - Mendoza. Instituto de Medicina y BiologĂa Experimental de Cuyo; ArgentinaFil: Spina Zapata, Renata MarĂa. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico Conicet - Mendoza. Instituto de HistologĂa y EmbriologĂa de Mendoza Dr. Mario H. Burgos. Universidad Nacional de Cuyo. Facultad de Ciencias MĂ©dicas. Instituto de HistologĂa y EmbriologĂa de Mendoza Dr. Mario H. Burgos; ArgentinaFil: Barrera, Patricia Andrea. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico Conicet - Mendoza. Instituto de HistologĂa y EmbriologĂa de Mendoza Dr. Mario H. Burgos. Universidad Nacional de Cuyo. Facultad de Ciencias MĂ©dicas. Instituto de HistologĂa y EmbriologĂa de Mendoza Dr. Mario H. Burgos; ArgentinaFil: Tonn, Carlos Eugenio. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico Conicet - San Luis. Instituto de Investigaciones en TecnologĂa QuĂmica. Universidad Nacional de San Luis. Facultad de QuĂmica, BioquĂmica y Farmacia. Instituto de Investigaciones en TecnologĂa QuĂmica; ArgentinaFil: Sosa Escudero, Miguel Angel. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico Conicet - Mendoza. Instituto de HistologĂa y EmbriologĂa de Mendoza Dr. Mario H. Burgos. Universidad Nacional de Cuyo. Facultad de Ciencias MĂ©dicas. Instituto de HistologĂa y EmbriologĂa de Mendoza Dr. Mario H. Burgos; Argentin
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Characterization of nonlinear dynamic systems using artificial neural networks
The efficient characterization of nonlinear systems is an important goal of vibration and model testing. The authors build a nonlinear system model based on the acceleration time series response of a single input, multiple output system. A series of local linear models are used as a template to train artificial neutral networks (ANNs). The trained ANNs map measured time series responses into states of a nonlinear system. Another NN propagates response states in time, and a third ANN inverts the original map, transforming states into acceleration predictions in the measurement domain. The technique is illustrated using a nonlinear oscillator, in which quadratic and cubic stiffness terms play a major part in the system`s response. Reasonable maps are obtained for the states, and accurate, long-term response predictions are made for data outside the training data set
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