4,645 research outputs found
A Rule-Based Approach to Analyzing Database Schema Objects with Datalog
Database schema elements such as tables, views, triggers and functions are
typically defined with many interrelationships. In order to support database
users in understanding a given schema, a rule-based approach for analyzing the
respective dependencies is proposed using Datalog expressions. We show that
many interesting properties of schema elements can be systematically determined
this way. The expressiveness of the proposed analysis is exemplarily shown with
the problem of computing induced functional dependencies for derived relations.
The propagation of functional dependencies plays an important role in data
integration and query optimization but represents an undecidable problem in
general. And yet, our rule-based analysis covers all relational operators as
well as linear recursive expressions in a systematic way showing the depth of
analysis possible by our proposal. The analysis of functional dependencies is
well-integrated in a uniform approach to analyzing dependencies between schema
elements in general.Comment: Pre-proceedings paper presented at the 27th International Symposium
on Logic-Based Program Synthesis and Transformation (LOPSTR 2017), Namur,
Belgium, 10-12 October 2017 (arXiv:1708.07854
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A major T cell antigen of Mycobacterium leprae is a 10-kD heat-shock cognate protein.
Several mycobacterial antigens, identified by monoclonal antibodies and patient sera, have been found to be homologous to stress or heat-shock proteins (hsp) defined in Escherichia coli and yeast. A major antigen recognized by most Mycobacterium leprae-reactive human T cell lines and cell wall-reactive T cell clones is a 10-kD protein that has now been cloned and sequenced. The predicted amino acid sequence of this protein is 44% homologous to the hsp 10 (GroES) of E. coli. The purified native and recombinant 10-kD protein was found to be a stronger stimulator of peripheral blood T cell proliferation than other native and recombinant M. leprae proteins tested. The degree of reactivity paralleled the response to intact M. leprae throughout the spectrum of leprosy. Limiting-dilution analysis of peripheral blood lymphocytes from a patient contact and a tuberculoid patient indicated that approximately one third of M. leprae-reactive T cell precursors responded to the 10-kD antigen. T cell lines derived from lepromin skin tests were strongly responsive to the 10-kD protein. T cell clones reactive to both the purified native and recombinant 10-kD antigens recognized M. leprae-specific epitopes as well as epitopes crossreactive with the cognate antigen of M. tuberculosis. Further, the purified hsp 10 elicited strong delayed-type hypersensitivity reactions in guinea pigs sensitized to M. leprae. The strong T cell responses against the M. leprae 10-kD protein suggest a role for this heat-shock cognate protein in the protective/resistant responses to infection
Numerical analysis of fracture in interpenetrating phase composites based on crack phase field model
A numerical model based on crack phase field analysis is introduced to study the quasi-static fracture process in interpenetrating phase composites (IPCs). Materials were considered elastic solids, and the interface was assumed to be perfectly bonded. Tougher and stiffer tougheners lead to more fracture in the brittle phase, but less fracture in the toughening phase. Thus, the overall fracture performance results from competition between increasing breakage in the brittle phase and declining breakage in the toughening phase. The toughening mechanisms are discussed from both stress-strain and crack topology viewpoints. The toughening phase transfers the load from the crack tip to the whole domain until the maximum stress is reached, and impeded crack growth occurs afterwards. The load transferring and impediment effects made the brittle phase engage in fracture, and several crack propagation patterns were identified for the sacrificial fracture behaviour, namely, crack deflection, crack bridging, crack branching, microcracking and crack blocking. Moreover, fracture in three different microstructures (co-continuous, particle-reinforced, laminar) was compared, and the most effective toughening morphology depends on the tougheners and the loading states. This methodology enables optimum microstructures to be identified to achieve high toughness in aerospace and energy generation applications, increasing safety and reducing weight
XMM-Newton observation of the ultraluminous quasar SDSS J010013.02+280225.8 at redshift 6.326
A brief Chandra observation of the ultraluminous quasar SDSS J010013.02+280225.8 at redshift 6.326 showed it to be a relatively bright, soft X-ray source with a count rate of about 1 count ksâ1. In this article, we present results for the quasar from a 65-ks XMMâNewton observation, which constrains its spectral shape well. The quasar is clearly detected with a total of ~460 net counts in the 0.2â10 keV band. The spectrum is characterized by a simple power-law model with a photon index of = 2.30+0.10 â0.10 and the intrinsic 2â10 keV luminosity is 3.14 Ă 1045 erg sâ1. The 1Ï upper limit to any intrinsic absorption column density is NH = 6.07 Ă 1022 cmâ2. No significant iron emission lines were detected. We derive an X-rayto-optical flux ratio αox of â1.74 ± 0.01, consistent with the values found in other quasars of comparable ultraviolet luminosity. We did not detect significant flux variations either in the XMMâNewton exposure or between XMMâNewton and Chandra observations, which are separated by âŒ8 months. The X-ray observation enables the bolometric luminosity to be calculated after modelling the spectral energy distribution: the accretion rate is found to be sub-Eddington
Prognostic ability of a panel of immunohistochemistry markers â retailoring of an 'old solution'
An urgent requirement exists for new prognostic and predictive assays in breast cancer. Despite the development of high-throughput technologies such as DNA microarrays, it would now appear that immunohistochemistry (IHC) may play an increasingly important role in the clinical management of breast cancer. In this editorial, the authors discuss the potential prognostic ability of a panel of IHC markers, and question whether this well-established assay technology may in fact allow for improved prognostic and predictive tests in breast cancer
Learning Gradient Fields for Shape Generation
In this work, we propose a novel technique to generate shapes from point
cloud data. A point cloud can be viewed as samples from a distribution of 3D
points whose density is concentrated near the surface of the shape. Point cloud
generation thus amounts to moving randomly sampled points to high-density
areas. We generate point clouds by performing stochastic gradient ascent on an
unnormalized probability density, thereby moving sampled points toward the
high-likelihood regions. Our model directly predicts the gradient of the log
density field and can be trained with a simple objective adapted from
score-based generative models. We show that our method can reach
state-of-the-art performance for point cloud auto-encoding and generation,
while also allowing for extraction of a high-quality implicit surface. Code is
available at https://github.com/RuojinCai/ShapeGF.Comment: Published in ECCV 2020 (Spotlight); Project page:
https://www.cs.cornell.edu/~ruojin/ShapeGF
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