915 resultados para Orthogonal polynomials on the real line


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It is almost a tradition that celluloid (or digital) villains are represented with some characteristics that remind us the real political enemies of the producer country of the film, or even enemies within the country according to the particular ideology that sustains the film. The case of Christopher Nolan The Dark Knight trilogy, analyzed here, is representative of this trend for two reasons. First, because it gets marked by political radicalization conducted by the US government after the attack of September 11, 2001. Secondly, because it offers a profuse gallery of villains who are outside the circle of friends as the new doctrine “either with us or against us” opened by George Bush for the XXI century. This gallery includes from the very terrorists who justify the War on Terror (Ra's al Ghul, the Joker), to the “radical left” (Bane, Talia al Ghul) including liberal politicians (Harvey Dent), and corrupt that take advantage of the softness of the law to commit crimes with impunity (Dr. Crane, the Scarecrow).

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This note presents a simple model for prediction of liquid hold-up in two-phase horizontal pipe flow for the stratified roll wave (St+RW) flow regime. Liquid hold-up data for horizontal two-phase pipe flow [1, 2, 3, 4, 5 and 6] exhibit a steady increase with liquid velocity and a more dramatic fall with increasing gas rate as shown by Hand et al. [7 and 8] for example. In addition the liquid hold-up is reported to show an additional variation with pipe diameter. Generally, if the initial liquid rate for the no-gas flow condition gives a liquid height below the pipe centre line, the flow patterns pass successively through the stratified (St), stratified ripple (St+R), stratified roll wave, film plus droplet (F+D) and finally the annular (A+D, A+RW, A+BTS) regimes as the gas rate is increased. Hand et al. [7 and 8] have given a detailed description of this progression in flow regime development and definitions of the patterns involved. Despite the fact that there are over one hundred models which have been developed to predict liquid hold-up, none have been shown to be universally useful, while only a handful have proven to be applicable to specific flow regimes [9, 10, 11 and 12]. One of the most intractable regimes to predict has been the stratified roll wave pattern where the liquid hold-up shows the most dramatic change with gas flow rate. It has been suggested that the momentum balance-type models, which give both hold-up and pressure drop prediction, can predict universally for all flow regimes but particularly in the case of the difficult stratified roll wave pattern. Donnelly [1] recently demonstrated that the momentum balance models experienced some difficulties in the prediction of this regime. Without going into lengthy details, these models differ in the assumed friction factor or shear stress on the surfaces within the pipe particularly at the liquid–gas interface. The Baker–Jardine model [13] when tested against the 0.0454 m i.d. data of Nguyen [2] exhibited a wide scatter for both liquid hold-up and pressure drop as shown in Fig. 1. The Andritsos–Hanratty model [14] gave better prediction of pressure drop but a wide scatter for liquid hold-up estimation (cf. Fig. 2) when tested against the 0.0935 m i.d. data of Hand [5]. The Spedding–Hand model [15], shown in Fig. 3 against the data of Hand [5], gave improved performance but was still unsatisfactory with the prediction of hold-up for stratified-type flows. The MARS model of Grolman [6] gave better prediction of hold-up (cf. Fig. 4) but deterioration in the estimation of pressure drop when tested against the data of Nguyen [2]. Thus no method is available that will accurately predict liquid hold-up across the whole range of flow patterns but particularly for the stratified plus roll wavy regime. The position is particularly unfortunate since the stratified-type regimes are perhaps the most predominant pattern found in multiphase lines.

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Quantitative application of elastoplastic theory to the yielding behaviour of natural soils has always been uncertain. Part of the reason is that the theory was developed for reconstituted materials with isotropic structure, in contrast to natural soils that are usually anisotropic. The approach considered in this study assumes that pre-yielding behaviour is governed by the theory of linear anisotropic elasticity and that yield loci in the mean effective stress ( p') – deviator stress (q) plane are aligned approximately along the coefficient of earth pressure (K0) line. The assumption of a rotated yield locus associated with anisotropic elastic behaviour within the state boundary surface indicates that the elastic wall within the state boundary surface is inclined. The form of the state boundary surface has been determined mathematically in terms of anisotropic elastic and Cam-Clay soil parameters. Stress path tests were conducted on samples of Belfast Upper Boulder Clay removed from a depth of 28 m below ground surface. Good agreement was found between predicted and measured yield loci. The study also examined the influence of subsequent isotropic compression on the yielding characteristics of the natural clay. The indications are that the anisotropy developed during deposition disappears when the sample is loaded to a stress level at least twice the stress generated during the original deposition process. The methods developed in the paper have also been applied to test results reported previously on Winnipeg clay, and good agreement was obtained.

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We present results from the first high-resolution, high signal-to-noise ratio spectrum of SN 2002ic. The resolved Ha line has a P Cygni-type profile, clearly demonstrating the presence of a dense, slow-moving (~100 km s-1) outflow. We have additionally found a huge near-infrared excess, hitherto unseen in Type Ia supernovae. We argue that this is due to an infrared light-echo arising from the pre-existing dusty circumstellar medium. We deduce a circumstellar medium mass probably exceeding 0.3 Msolar produced by a mass-loss rate greater than several times 10-4 Msolar yr-1. For the progenitor, we favour a single-degenerate system where the companion is a post-asymptotic giant branch star. As a by-product of our optical data, we are able to provide a firm identification of the host galaxy of SN 2002ic.

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We study the classes of homogeneous polynomials on a Banach space with unconditional Schauder basis that have unconditionally convergent monomial expansions relative to this basis. We extend some results of Matos, and we show that the homogeneous polynomials with unconditionally convergent expansions coincide with the polynomials that are regular with respect to the Banach lattices structure of the domain.

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The effects of diabetes mellitus on male reproductive health have not been clearly defined. A previous publication from this group reported significantly higher levels of nuclear DNA fragmentation and mitochondrial DNA deletions in spermatozoa from men with type 1 diabetes. This study compared semen profiles, sperm DNA fragmentation and levels of oxidative DNA modification in spermatozoa of diabetic and non-diabetic men. Semen samples from 12 non-diabetic, fertile men and 11 type 1 diabetics were obtained and subjected to conventional light microscopic semen analysis. Nuclear DNA fragmentation was assessed using an alkaline Comet assay and concentrations of 7,8-dihydro-8-oxo-2-deoxyguanosine (8-OHdG), an oxidative adduct of the purine guanosine, were assessed by high-performance liquid chromatography. Conventional semen profiles were similar in both groups, whilst spermatozoa from type 1 diabetics showed significantly higher levels of DNA fragmentation (44% versus 27%; P < 0.05) and concentrations of 8-OHdG (3.6 versus 2.0 molecules of 8-OHdG per 105 molecules of deoxyguanosine; P < 0.05). Furthermore, a positive correlation was observed between DNA fragmentation and concentrations of 8-OHdG per 105 molecules of deoxyguanosine (rs = 0.7, P < 0.05). The genomic damage evident in spermatozoa of type 1 diabetics may have important implications for their fertility and the outcome of pregnancies fathered by these individuals.

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CO multipulse temporal analysis of products (TAP) experiments were used to characterize a ceria-supported platinum catalyst after various oxidative and reductive pretreatments using O-2, H2O, CO2, and H-2. Based on the amount of CO consumed, using the final CO-saturated catalyst composition as the common state point, the oxidatively pretreated catalyst could be described using a general scale. From a kinetic analysis of the CO multipulse responses, two kinetic regimes corresponding to two types of active sites could be identified. As the temperature was raised, the number of the most active sites did not change while the amount of the less active site increased. Comparison of the number of active sites determined from the TAP data reported herein with that determined by a previous steady-state isotope transient kinetic analysis experiment showed excellent agreement. This correlation indicates that the (very fast response) TAP experiments can provide information regarding the number and type of active sites that are relevant to a catalyst under real reaction conditions. (c) 2007 Elsevier Inc. All rights reserved.

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Within undergraduate psychology courses, students often have significant levels of anxiety and negative attitudes toward the statistical element. This has been attributed to poor interaction with teachers, fears about mathematical abilities, and simply being unaware of that portion of the course or its relevance to psychology. To address this, 196 undergraduate psychology students completed a survey on statistics anxiety and attitudes. Additionally, 27 different students in similar situations took part in focus group to share their experiences of introductory statistics courses. Survey results showed that fewer than half were aware of the statistics portion of their course and that the expectation was a key factor in their experiences. Qualitative feedback from the focus groups revealed much about how the teaching may or may not improve attitudes nor decrease anxiety. Findings support various broad strategies (i.e. increase awareness of statistics in psychology and confidence in success in the course) as opposed to skill-specific (better ways of teaching probability or using games to increase participation, for example) classroom interventions to improve statistics education.

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Aims. We study the dependence of the profiles of molecular abundances and line emission on the accretion flow in the hot (100 K) inner region of protoplanetary disks.
Methods. The gas-phase reactions initiated by evaporation of the ice mantle on dust grains are calculated along the accretion flow. We focus on methanol, a molecule that is formed predominantly by the evaporation of warm ice mantles, to demonstrate how its abundance profile and line emission depend on the accretion flow.
Results. Our results indicate that some evaporated molecules retain high abundances only when the accretion velocity is sufficiently high, and that methanol could be useful as a diagnostic of the accretion flow by means of ALMA observations at the disk radius of 10 AU.

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A curved crystal spectrometer in Johann configuration has been implemented on MAST to obtain values for electron temperature, ion temperature and toroidal velocity. The spectrometer is used to examine medium Z impurities in the soft x-ray region by utilising a Silicon (111) crystal, bent using a 4 pin bending jig, and a CCD detector (Deltat=8 ms). Helium-like Argon emissions from 3.94 to 4.00 Angstrom have been examined using a crystal radius of 859.77 mm. The Bragg angle and crystal radius can be adjusted with relative ease. The spectrometer can be scanned toroidally and poloidally to include a radial view which facilitates absolute velocity measurements by assuming radial velocity =0. Doppler shifts of 2.3x10(-5) Angstrom (1.8 kms(-1)) can be measured. The line of sight is shared with a neutral particle analyzer, which enables in situ ion temperature comparisons. Ray tracing has been used for the development of new imaging spectrometers, using spherical/toroidal crystals, planned to be implemented on MAST. (C) 2004 American Institute of Physics.

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Context: The masses previously obtained for the X-ray binary 2S 0921-630 inferred a compact object that was either a high-mass neutron star or low-mass black-hole, but used a previously published value for the rotational broadening (v sin i) with large uncertainties. Aims: We aim to determine an accurate mass for the compact object through an improved measurement of the secondary star's projected equatorial rotational velocity. Methods: We have used UVES echelle spectroscopy to determine the v sin i of the secondary star (V395 Car) in the low-mass X-ray binary 2S 0921-630 by comparison to an artificially broadened spectral-type template star. In addition, we have also measured v sin i from a single high signal-to-noise ratio absorption line profile calculated using the method of Least-Squares Deconvolution (LSD). Results: We determine v sin i to lie between 31.3±0.5 km s-1 to 34.7±0.5 km s-1 (assuming zero and continuum limb darkening, respectively) in disagreement with previous results based on intermediate resolution spectroscopy obtained with the 3.6 m NTT. Using our revised v sin i value in combination with the secondary star's radial velocity gives a binary mass ratio of 0.281±0.034. Furthermore, assuming a binary inclination angle of 75° gives a compact object mass of 1.37±0.13 M_?. Conclusions: We find that using relatively low-resolution spectroscopy can result in systemic uncertainties in the measured v sin i values obtained using standard methods. We suggest the use of LSD as a secondary, reliable check of the results as LSD allows one to directly discern the shape of the absorption line profile. In the light of the new v sin i measurement, we have revised down the compact object's mass, such that it is now compatible with a canonical neutron star mass.

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This paper describes the application of multivariate regression techniques to the Tennessee Eastman benchmark process for modelling and fault detection. Two methods are applied : linear partial least squares, and a nonlinear variant of this procedure using a radial basis function inner relation. The performance of the RBF networks is enhanced through the use of a recently developed training algorithm which uses quasi-Newton optimization to ensure an efficient and parsimonious network; details of this algorithm can be found in this paper. The PLS and PLS/RBF methods are then used to create on-line inferential models of delayed process measurements. As these measurements relate to the final product composition, these models suggest that on-line statistical quality control analysis should be possible for this plant. The generation of `soft sensors' for these measurements has the further effect of introducing a redundant element into the system, redundancy which can then be used to generate a fault detection and isolation scheme for these sensors. This is achieved by arranging the sensors and models in a manner comparable to the dedicated estimator scheme of Clarke et al. 1975, IEEE Trans. Pero. Elect. Sys., AES-14R, 465-473. The effectiveness of this scheme is demonstrated on a series of simulated sensor and process faults, with full detection and isolation shown to be possible for sensor malfunctions, and detection feasible in the case of process faults. Suggestions for enhancing the diagnostic capacity in the latter case are covered towards the end of the paper.

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This paper describes an experimental investigation of the behaviour of corroded reinforced concrete beams. These have been stored in a chloride environment for a period of 26 years under service loading so as to be representative of real structural and environmental conditions. The configuration and the widths of the cracks in the two seriously corroded short-span beams were depicted carefully, and then the beams were tested until failure by a three-point loading system. Another two beams of the same age but without corrosion were also tested as control specimens. A short span arrangement was chosen to investigate any effect of a reduction in the area and bond strength of the reinforcement on shear capacity. The relationship of load and deflection was recorded so as to better understand the mechanical behaviour of the corroded beams, together with the slip of the tensile bars. The corrosion maps and the loss of area of the tensile bars were also described after having extracted the corroded bars from the concrete beams. Tensile tests of the main longitudinal bars were also carried out. The residual mechanical behaviour of the beams is discussed in terms of the experimental results and the cracking maps. The results show that the corrosion of the reinforcement in the beams induced by chloride has a very important effect on the mechanical behaviour of the short-span beams, as loss of cross-sectional area and bond strength have a very significant effect on the bending capacity.

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In this letter, the performance bound of the IEEE 802.16d channel is examined analytically in order to gain an insight into its theoretical potential. Different design strategies, such as orthogonal frequency division multiplexing (OFDM) and single-carrier frequency-domain equalization (SC-FDE), time-domain decision feedback equalization (DFE), and sphere decoder (SD) techniques are discussed and compared to the theoretical bound.

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Bradykinin and related peptides are found in the defensive skin secretions of many frogs and toads. While the physiological roles of bradykinin-related peptides in sub-mammalian vertebrates remains obscure, in mammals, including humans, canonical bradykinin mediates a multitude of biological effects including the proliferation of many types of cancer cell. Here we have examined the effect of the bradykinin B2 receptor antagonist peptide, kinestatin, originally isolated by our group from the skin secretion of the giant fire-bellied toad, Bombina maxima, on the proliferation of the human prostate cancer cell lines, PC3, DU175 and LnCAP. The bradykinin receptor status of all cell lines investigated was established through PCR amplification of transcripts encoding both B1 and B2 receptor subtypes. Following this demonstration, all cell lines were grown in the presence or absence of kinestatin and several additional bradykinin receptor antagonists of amphibian skin origin and the effects on proliferation of the cell lines was investigated using the MTT assay and by counting of the cells in individual wells of 96-well plates. All of the amphibian skin secretion-derived bradykinin receptor antagonists inhibited proliferation of all of the prostate cancer lines investigated in a dose-dependent manner. In addition, following incubation of peptides with each cell line and analysis of catabolites by mass spectrometry, it was found that bradykinin was highly labile and each antagonist was highly stable under the conditions employed. Bradykinin signalling pathways are thus worthy of further investigation in human prostate cancer cell lines and the evidence presented here would suggest the testing of efficacy in animal models of prostate cancer as a positive outcome could lead to a drug development programme for the treatment of this disease.