Concatenated dynamical decoupling with virtual pulses

The loss of quantum information due to interaction with external degrees of freedom, which is known as decoherence, remains one of the main obstacles for large-scale implementations of quantum computing. Accordingly, different measures are being explored for reducing its effect. One of them is dynamical decoupling (DD) which offers a practical solution because it only requires the application of control pulses to the system qubits. Starting from basic DD sequences, more sophisticated schemes were developed that eliminate higher-order terms of the system-environment interaction and are also more robust against experimental imperfections. A particularly successful scheme, called concatenated DD (CDD), gives a recipe for generating higher order sequences by inserting lower order sequences into the delays of a generating sequence. Here, we show how this scheme can be improved further by converting some of the pulses to virtual (and thus ideal) pulses. The resulting scheme, called vCDD, has lower power deposition and is more robust against pulse imperfections than the original CDD scheme.Comment: 9 pages, 9 figure

Cadastro de pessoas

Esta nota técnica apresenta os problemas e propõe soluções técnicas para a implantação do processo de atualização dos dados cadastrais. A atualização dos dados cadastrais dos usuários da rede UNA-SUS é um processo desejável para a evolução da segurança, qualidade e a validade da informação administrada pela Secretaria Executiva do Sistema UNA-SUS (SE-UNA-SUS)

Interregional input-ouptut system for Ecuador, 2007: methodology and results

In this paper, we explore the structural characteristics of the interregional input-output system developed for Ecuador for the year 2007. As part of an ongoing project that aims to develop an interregional CGE model for the country, this database was developed under conditions of limited information. It provides the opportunity to better understand the spatial linkage structure associated with the national economy in the context of its 22 provinces, 15 sectors and 60 different products. This exploratory analysis is based on the description of structural coefficients and the use of traditional input-output techniques. Finally, we further explore the spatial linkage structure by looking at the regional decomposition of final demand. It is hoped that this exercise might result in a better appreciation of a broader set of dimensions that might improve our understanding of the integrated interregional economic system in Ecuador.Interregional input-output model; Ecuador; spatial linkages

Topological Line Defects around Graphene Nanopores for DNA Sequencing

Topological line defects in graphene represent an ideal way to produce highly controlled structures with reduced dimensionality that can be used in electronic devices. In this work we propose using extended line defects in graphene to improve nucleobase selectivity in nanopore-based DNA sequencing devices. We use a combination of QM/MM and non-equilibrium Green's functions methods to investigate the conductance modulation, fully accounting for solvent effects. By sampling over a large number of different orientations generated from molecular dynamics simulations, we theoretically demonstrate that distinguishing between the four nucleobases using line defects in a graphene-based electronic device appears possible. The changes in conductance are associated with transport across specific molecular states near the Fermi level and their coupling to the pore. Through the application of a specifically tuned gate voltage, such a device would be able to discriminate the four types of nucleobases more reliably than that of graphene sensors without topological line defects.Comment: 6 figures and 6 page

Molecular polymorphism, differentiation and introgression in the period gene between Lutzomyia intermedia and Lutzomyia whitmani

BACKGROUND: Lutzomyia intermedia and Lutzomyia whitmani (Diptera: Psychodidae) are important and very closely related vector species of cutaneous leishmaniasis in Brazil, which are distinguishable by a few morphological differences. There is evidence of mitochondrial introgression between the two species but it is not clear whether gene flow also occurs in nuclear genes. RESULTS: We analyzed the molecular variation within the clock gene period (per) of these two species in five different localities in Eastern Brazil. AMOVA and Fst estimates showed no evidence for geographical differentiation within species. On the other hand, the values were highly significant for both analyses between species. The two species show no fixed differences and a higher number of shared polymorphisms compared to exclusive mutations. In addition, some haplotypes that are "typical" of one species were found in some individuals of the other species suggesting either the persistence of old polymorphisms or the occurrence of introgression. Two tests of gene flow, one based on linkage disequilibrium and a MCMC analysis based on coalescence, suggest that the two species might be exchanging alleles at the per locus. CONCLUSION: Introgression might be occurring between L. intermedia and L. whitmani in period, a gene controlling behavioral rhythms in Drosophila. This result raises the question of whether similar phenomena are occurring at other loci controlling important aspects of behavior and vectorial capacity

Rhythmic expression of the cycle gene in a hematophagous insect vector

BACKGROUND: A large number of organisms have internal circadian clocks that enable them to adapt to the cyclic changes of the external environment. In the model organism Drosophila melanogaster, feedback loops of transcription and translation are believed to be crucial for the maintenance of the central pacemaker. In this mechanism the cycle (or bmal1) gene, which is constitutively expressed, plays a critical role activating the expression of genes that will later inhibit their own activity, thereby closing the loop. Unlike Drosophila, the molecular clock of insect vectors is poorly understood, despite the importance of circadian behavior in the dynamic of disease transmission. RESULTS: Here we describe the sequence, genomic organization and circadian expression of cycle in the crepuscular/nocturnal hematophagous sandfly Lutzomyia longipalpis, the main vector of visceral leishmaniasis in the Americas. Deduced amino acid sequence revealed that sandfly cycle has a C-terminal transactivation domain highly conserved among eukaryotes but absent in D. melanogaster. Moreover, an alternative form of the transcript was also identified. Interestingly, while cycle expression in Drosophila and other Diptera is constitutive, in sandflies it is rhythmic in males and female heads but constitutive in the female body. Blood-feeding, which causes down-regulation of period and timeless in this species, does not affect cycle expression. CONCLUSION: Sequence and expression analysis of cycle in L. longipalpis show interesting differences compared to Drosophila suggesting that hematophagous vector species might present interesting new models to study the molecular control of insect circadian clocks