29 research outputs found

    On the Hybrid Extension of CTL and CTL+

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    The paper studies the expressivity, relative succinctness and complexity of satisfiability for hybrid extensions of the branching-time logics CTL and CTL+ by variables. Previous complexity results show that only fragments with one variable do have elementary complexity. It is shown that H1CTL+ and H1CTL, the hybrid extensions with one variable of CTL+ and CTL, respectively, are expressively equivalent but H1CTL+ is exponentially more succinct than H1CTL. On the other hand, HCTL+, the hybrid extension of CTL with arbitrarily many variables does not capture CTL*, as it even cannot express the simple CTL* property EGFp. The satisfiability problem for H1CTL+ is complete for triply exponential time, this remains true for quite weak fragments and quite strong extensions of the logic

    Characteristics of Quantum-Classical Correspondence for Two Interacting Spins

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    The conditions of quantum-classical correspondence for a system of two interacting spins are investigated. Differences between quantum expectation values and classical Liouville averages are examined for both regular and chaotic dynamics well beyond the short-time regime of narrow states. We find that quantum-classical differences initially grow exponentially with a characteristic exponent consistently larger than the largest Lyapunov exponent. We provide numerical evidence that the time of the break between the quantum and classical predictions scales as log(J/{\cal J}/ \hbar), where J{\cal J} is a characteristic system action. However, this log break-time rule applies only while the quantum-classical deviations are smaller than order hbar. We find that the quantum observables remain well approximated by classical Liouville averages over long times even for the chaotic motions of a few degree-of-freedom system. To obtain this correspondence it is not necessary to introduce the decoherence effects of a many degree-of-freedom environment.Comment: New introduction, accepted in Phys Rev A (May 2001 issue), 12 latex figures, 3 ps figure

    HI in the Outskirts of Nearby Galaxies

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    The HI in disk galaxies frequently extends beyond the optical image, and can trace the dark matter there. I briefly highlight the history of high spatial resolution HI imaging, the contribution it made to the dark matter problem, and the current tension between several dynamical methods to break the disk-halo degeneracy. I then turn to the flaring problem, which could in principle probe the shape of the dark halo. Instead, however, a lot of attention is now devoted to understanding the role of gas accretion via galactic fountains. The current Λ\rm \Lambda cold dark matter theory has problems on galactic scales, such as the core-cusp problem, which can be addressed with HI observations of dwarf galaxies. For a similar range in rotation velocities, galaxies of type Sd have thin disks, while those of type Im are much thicker. After a few comments on modified Newtonian dynamics and on irregular galaxies, I close with statistics on the HI extent of galaxies.Comment: 38 pages, 17 figures, invited review, book chapter in "Outskirts of Galaxies", Eds. J. H. Knapen, J. C. Lee and A. Gil de Paz, Astrophysics and Space Science Library, Springer, in pres

    Reactor physics project progress report no. 2

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    Statement of responsibility on title page reads: Editors: M.J. Driscoll, I. Kaplan, D.D. Lanning; Contributors: V. Agarwala, F.M. Clikeman, J.N. Donohew, M.J. Driscoll, G. T. Hamilton, T.L. Harper, Y. Hukai, I. Kaplan, T. J. Kelley, D.D. Lanning, T.C. Leung, E.L. McFarland, N.C. Rasmussen, S.S. Seth, J.M. Sicilian, G.E. Sullivan, A.T.Supple and T.J. Thompson"September 30, 1969.""MIT-3944-4."Includes bibliographical referencesProgress report no. 2; October 1, 1968 through September 30. 1969This is the second annual report in an experimental and theoretical program to develop and apply single and few element heterogeneous methods for the determination of reactor lattice parameters. During the period covered by the report, October 1, 1968 through September 30. 1969, work was primarily devoted to measurement of the heterogeneous fuel element parameters (F, rl and A) of 19- and 31- rod clusters of plutonium-containing fuel. Methods development research focused on determination of the epithermal absorption constant, A. Calculations and an analysis of data reported in the literature were made to assess the applicability of heterogeneous methods to H 20- moderated systems. Advanced gamma spectrometric methods using Ge(Li) detectors were applied to the analysis of prompt and delayed gamma spectra from fertile and fissile materials and from fuel elements. These methods were used successfully for nondestructive analysis of the composition of fuel elements. A feasibility study was performed on an in-pile gamma spectrometer. Two fuel pins irradiated to a burnup of approximately 20,000 MWD/MT in the Dresden reactor were received and preparations made for their analysis and use in reactor physics experiments.U. S. Atomic Energy Commission contract AT(30-1)-394

    Four-Year Follow-Up of Intensive, Simulator-Based Pilot Training

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    Sixteen students, who began with 0-20 flight hours, enrolled in an intensive, simulator based, collegiate training program. They completed their training with fewer flight hours than the US average: FAA Private Pilot within 4-6 weeks; instrument ratings in 3-4 weeks; Commercial within an average of 20 weeks and CFI ratings in an average of 40 weeks and all graduated with Bachelor’s degrees (ISAP, 2013). The students had met selection criteria. At the time, indicators of success included variables associatedwith simulator based training, camaraderie, shared learning and opportunities to reflect on training. Four years later, 81% are now flying professionally: eight as flight instructors, four as first officer airline pilots, one commercial pilot, and three employed elsewhere in the aviation industry. This qualitative follow-up study suggests that initial, rapid learning was neither shallow nor short-lived. Most are still friends. They became active alumni and mentors for incoming flight students

    A comparative analysis of implementation of the Energy Performance of Buildings Directive in the Mediterranean

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    The Energy Performance of Buildings Directive (EPBD) 2002/91/EC introduced various obligatory requirements intended to achieve the reduction of use of energy resources in buildings. This directive had to be transposed into national legislation by the EU member states. Concurrently the European Committee for Standardisation developed a number of technical standards to assist member states to define the methodology for the calculation of the energy performance of buildings. The purpose of this paper is to present a comparative review of the relationship between the European directive and the standards, and the different country legislation and methodologies that have been implemented in Malta, Italy, Spain and Cyprus.peer-reviewe

    Determinação do número ótimo de classificações imperfeitas na avaliação da conformidade de produtos Determination of the optimal number of imperfect classifications in the evaluation of the conformity of products

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    Neste trabalho estudamos o número ótimo de classificações independentes por unidade produzida supondo que haja dois tipos de erro: o tipo I, no qual classifica-se um produto como não-conforme quando ele na realidade é conforme; e o tipo II, no qual classifica-se um produto como conforme quando na realidade é não-conforme. Desenvolvemos um modelo econômico para minimizar o custo médio total em função dos erros de classificação e do custo de cada classificação. Pela complexidade da função-objetivo associada ao modelo, utilizamos um procedimento exaustivo de busca juntamente com um limitante superior do valor ótimo. Todo o procedimento computacional teve uma implementação relativamente simples e está disponível como uma planilha eletrônica do Excel e um código do software estatístico Minitab.<br>In this study we investigate the optimal number of independent classifications per unit produced when there are two types of classification errors: type I, where product is classified as conforming when it is not in reality, and type II, where product is classified as non-conforming when in reality it is conforming. We developed an economic model to minimize the total medium cost as a function of the classification errors and the cost of each classification. Due to the complexity of the objective function associated to the model, we used an exhaustive procedure with an upper bound of the optimal value. The procedure may be implemented easily and is available either as an Excel spreadsheet or as a macro of the statistical software Minitab

    Influence of the year and calving season on production, composition and mozzarella cheese yield of water buffalo in the State of Rio Grande Do Norte, Brazil

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    This research was carried out to evaluate the influence of the year and calving season on the production, composition and mozzarella cheese yield index (PKM) of Murrah water buffalos. We analyzed a data set of 514 lactations collected from 2004 to 2008, recorded and archived in software of a farm located in Taipu, in the eastern region of Rio Grande do Norte State, Brazil. To assess the effects of calving season, the year was divided into a rainy season (from March to August) and a dry season (from September to February). Results showed that the year influenced daily production and PKM (P<0.05). However, no effects were observed on logarithm somatic cell count (LSCC), fat, protein and total dry extract (TDE). The season had no influence on the variables analyzed and no interaction was observed between the year and the season. The season and its interactions had no effect on water buffalo performance in relation to dairy production and PKM index of mozzarella efficiency

    A biophysical study of DNA condensation mediated by histones and protamines

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    The compaction of long DNA strands into confined spaces such as the nuclei of eukaryotic cells is an essential phenomenon towards the emergence of elaborated forms of life. Histones and protamines are the major nucleoproteins involved in this task participating in the formation of chromatin in somatic and germinative cells, respectively. In addition to a fundamental understanding of critical biological processes, DNA condensation also holds strong potential in biotechnology. Herein, we investigate the mesoscale structure of complexes formed between DNA and histones or protamines. A sophisticated set of biophysical methods encompassing steady-state fluorimetry, small-angle X-ray scattering and infrared nano spectroscopy was used to unveil both the self-assembly and molecular interactions of these complexes. We explored the fluorescence of a molecular rotor, thioflavin T, to investigate the accessibility of ligands in the inter-base environment of DNA strands. AFM-based infrared spectroscopy was used for the first time to probe the vibrational signature of individual DNA/nucleoprotein nano assemblies and disclose secondary-structure features. Our results show that protamines form highly compact structures in which DNA folding hinders access to the inter-base spacing. These assemblies exhibit diversified secondary-structure conformations, with the presence of -sheets stabilizing the packing. In contrast, histone-based complexes are characterized by fibrillar nano assemblies exhibiting larger inter strands separations and access to guest molecules that intercalate between bases. The findings presented here may help the understanding of DNA condensation mediated by these two major nucleoproteins and may assist the optimization of gene vehicles based on these promising nano assemblies.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)FAPESP, 19/20907-
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