33,597 research outputs found

    Measurement of anisotropies in the large-scale diffuse gamma-ray emission

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    We have performed the first measurement of the angular power spectrum in the large-scale diffuse emission at energies from 1-50 GeV. We compared results from data and a simulated model in order to identify significant differences in anisotropy properties. We found angular power above the photon noise level in the data at multipoles greater than ~ 100 for energies 1< E <10 GeV. The excess power in the data suggests a contribution from a point source population not present in the model.Comment: Contribution to SciNeGHE 2010, Trieste, Italy, September 2010; 4 pages, 5 figure

    Optimum matchings in weighted bipartite graphs

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    Given an integer weighted bipartite graph {G=(UV,E),w:EZ}\{G=(U\sqcup V, E), w:E\rightarrow \mathbb{Z}\} we consider the problems of finding all the edges that occur in some minimum weight matching of maximum cardinality and enumerating all the minimum weight perfect matchings. Moreover, we construct a subgraph GcsG_{cs} of GG which depends on an ϵ\epsilon-optimal solution of the dual linear program associated to the assignment problem on {G,w}\{G,w\} that allows us to reduced this problems to their unweighed variants on GcsG_{cs}. For instance, when GG has a perfect matching and we have an ϵ\epsilon-optimal solution of the dual linear program associated to the assignment problem on {G,w}\{G,w\}, we solve the problem of finding all the edges that occur in some minimum weight perfect matching in linear time on the number of edges. Therefore, starting from scratch we get an algorithm that solves this problem in time O(nmlog(nW))O(\sqrt{n}m\log(nW)), where n=UVn=|U|\geq |V|, m=Em=|E|, and W=max{w(e):eE}W={\rm max}\{|w(e)|\, :\, e\in E\}.Comment: 11 page

    Excited bands in odd-mass rare-earth nuclei

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    Normal parity bands are studied in 157Gd, 163Dy and 169Tm using the pseudo SU(3) shell model. Energies and B(E2) transition strengths of states belonging to six low-lying rotational bands with the same parity in each nuclei are presented. The pseudo SU(3) basis includes states with pseudo-spin 0 and 1, and 1/2 and 3/2, for even and odd number of nucleons, respectively. States with pseudo-spin 1 and 3/2 must be included for a proper description of some excited bands.Comment: 8 pages, 6 figures, Submitted to Phys. Rev.

    Non-Hermitian robust edge states in one-dimension: Anomalous localization and eigenspace condensation at exceptional points

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    Capital to topological insulators, the bulk-boundary correspondence ties a topological invariant computed from the bulk (extended) states with those at the boundary, which are hence robust to disorder. Here we put forward an ordering unique to non-Hermitian lattices, whereby a pristine system becomes devoid of extended states, a property which turns out to be robust to disorder. This is enabled by a peculiar type of non-Hermitian degeneracy where a macroscopic fraction of the states coalesce at a single point with geometrical multiplicity of 11, that we call a phenomenal point.Comment: 6 pages, 4 figure

    A 300 GHz "Always-in-Focus" Focusing System for Target Detection

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    A focusing system for a 300 GHz radar with 5 m target distance and 10 mm diameter spot size resolution is proposed. The focusing system is based on a Gaussian telescope scheme and its main parameters have been de¬signed using Gaussian beam quasi-optical propagation theory with an in-house developed MATLAB® based analysis tool. Then, this approach has been applied to a real focusing system based on two elliptical mirrors in order to reduce the distortion and cross-polar level and a plane mirror to provide scanning capabilities. The over¬all system has been simulated with a full-wave electromag¬netic simulator and its behavior is presented. With this approach, the focusing system always works "in-focus" since the only mirror that is rotated when scanning is the output plane mirror, so the beam is almost not distorted. The design process, although based in the well-known Gaussian beam quasi-optical propagation theory, provides a fast and accurate method and minimizes the overall size of the mirrors. As a consequence, the size of the focusing system is also reduced

    Neisseria gonorrhoeae challenge increases matrix metalloproteinase-8 expression in fallopian tube explants

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    Indexación: Scopus.Background: Neisseria gonorrhoeae (Ngo) is the etiological agent of gonorrhea, a sexually transmitted infection that initially infects the female lower genital tract. In untreated women, the bacteria can ascend to the upper genital reproductive tract and infect the fallopian tube (FTs), which is associated with salpingitis and can lead to impaired FT function and infertility. The extracellular matrix (ECM) plays an important role in cell migration and differentiation in the female genital tract, and some pathogens modify the ECM to establish successful infections. The ECM is regulated by matrix metalloproteinases (MMPs) and tissue inhibitors of metalloproteinases (TIMPs), their endogenous inhibitors; MMP deregulation causes pathological conditions in a variety of tissues. Results: The aim of this work was to analyze the expression and localization of MMP-3, MMP-8, MMP-9, and TIMP-1 in FT explants during Ngo infection using real-time PCR, immunohistochemistry, zymography and ELISA. No significant variations in MMP-3, MMP-9, and TIMP-1 transcript levels were observed. In contrast, a significant increase (p < 0.05) was observed for MMP-8 expression and was accompanied by stromal immunoreactivity in infected explants. ELISA results supported these findings and showed that MMP-8 release increased upon gonococcal infection. Conclusions: Our results indicate that gonococcal infection induces increased MMP-8 expression, which might contribute to FT damage during infection. © 2017 Juica, Rodas, Solar, Borda, Vargas, Muñoz, Paredes, Christodoulides and Velasquez.https://www.frontiersin.org/articles/10.3389/fcimb.2017.00399/ful

    Triad Model of Education (II) and Instructional Engineering

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    A pesar del dinero y el sudor que forman parte de las nuevas tecnologías instructivas, no producen el alto nivel global de logro por parte de los estudiantes que las sociedades buscan. Una enseñanza más efectiva requiere una solución profunda. Requiere una tríada coordinada de factores: una ciencia adecuada, una estructura organizacional correcta y una tecnología instructiva de ingeniería. Este segundo artículo de una serie de artículos sobre el Modelo Tríada de Educación se centra en la ingeniería instructiva. La ingeniería instructiva extraída de la ciencia se basa en las contingencias. Los sistemas basados en contingencias siempre manejan los dos componentes inevitables de la instrucción: los repertorios de los estudiantes y los contextos o escenarios que dan forma a dichos repertorios. El componente contextual consta de cinco elementos: la asignatura, los objetivos, el control de la calidad, los modos de presentación y la logística. El componente del repertorio consiste en el gobierno de los repertorios—gobernados por eventos y por la lengua, el tipo de repertorio—saber, resolver y crear y la variabilidad del repertorio—convergente y divergente. Estos elementos y su ingeniería necesaria revelan una tarea instructiva más compleja de lo que se había pensado con anterioridad. El progreso con dicha complejidad sólo ocurre cuando todos los componentes de la tríada se encuentran en su lugar.Despite the money and sweat that go into new instructional technologies, they do not produce the overall high level of student performances that societies seek. More effective teaching calls for a profound solution. It requires a coordinate triad of factors: a proper science, the correct organizational structure, and an engineering instructional technology. This second of a series of articles on the Triad Model of Education concentrates on instructional engineering. The instructional engineering drawn from the science is contingency-based. Contingency-based instructional systems always handle the inevitable two components of instruction: the repertoires of students and the setups that shape those repertoires. The setup component features five elements: subject matter, objectives, quality control, presentation modes, and logistics. The repertoire component consists of the governance of repertoires—event and lingual governed, the type of repertoire—knowing, solving, and creating, and the variability of the repertoire—convergent and divergent. These elements, and their required engineering, reveal an instructional task more complex than previously considered. Progress with such complexity occurs only when all components of the triad are in place

    Microscopic study of neutron-rich Dysprosium isotopes

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    Microscopic studies in heavy nuclei are very scarce due to large valence spaces involved. This computational problem can be avoided by means of the use of symmetry based models. Ground-state, gamma and beta-bands, and their B(E2) transition strengths in 160-168Dy isotopes, are studied in the framework of the pseudo-SU(3) model which includes the preserving symmetry Q.Q term and the symmetry-breaking Nilsson and pairing terms, systematically parametrized. Additionally, three rotor-like terms are considered whose free parameters, fixed for all members of the chain are used to fine tune the moment of inertia of rotational bands and the band-head of gamma and beta-bands. The model succesfully describes in a systematic way rotational features in these nuclei and allows to extrapolate toward the midshell nucleus 170Dy. The results presented show that it is possible to study full chain of isotopes or isotones in the region with the present model
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