948 resultados para non-reproducibility of the cross sections


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First published in Russian in the "Russkoe slovo," October, 1915.

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The buffer allocation problem (BAP) is a well-known difficult problem in the design of production lines. We present a stochastic algorithm for solving the BAP, based on the cross-entropy method, a new paradigm for stochastic optimization. The algorithm involves the following iterative steps: (a) the generation of buffer allocations according to a certain random mechanism, followed by (b) the modification of this mechanism on the basis of cross-entropy minimization. Through various numerical experiments we demonstrate the efficiency of the proposed algorithm and show that the method can quickly generate (near-)optimal buffer allocations for fairly large production lines.

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* Partialy supported by contract MM 523/95 with Ministry of Science and Technologies of Republic of Bulgaria.

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Based on a geometry problem by Ivan Salabashev we demonstrate an exploratory process leading to conic sections as a locus of points. We work for the purpose with the GeoGebra dynamic software making use of different objects’ representations for explorations related with conic sections.

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This study examined relationships among variables in the Pre-International Baccalaureate (Pre-IB) Program admissions criteria and the Pre-IB Program course grades to discriminate between recipient and non recipient groups of the International Baccalaureate (IB) Diploma award. The study involved a multiracial sample of 142 IB Diploma graduates between the years 1992 and 1996 from one IB magnet school. The IB school is located within an urban high school of a predominantly Black student enrollment. A discriminant function analysis found that the highest correlations between predictors and the discriminant function were 9th- and 10th-grade mathematics and 10th-grade science course grades. Ninth-grade course grades of science, 9th-grade and 10th-grade course grades of English, foreign language, and social studies, and 7th-grade Iowa Tests of Basic Skills (ITBS) Reading Comprehension scores were also highly correlated to the discriminant function. The ITBS Battery and subscores of Vocabulary, Total Language, Total Work-Study, and Total Mathematics subscores in seventh grade and a grade point average from language arts, social studies, science, and mathematics in seventh grade were not highly correlated to the discriminant function. Recommendations were presented in the areas of curriculum and instruction, guidance services, student mentoring, and decision-making processes which would parallel the IB examination procedure and thereby enhance the alignment of the IB Program enabling more students to become recipients of the IB Diploma award. ^

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The Cross-Florida Barge Canal, synonymous with boondoggle and waste, became the cause celebre of environmental activism in Florida of the late 1960s. Dramatic changes in Florida's and the nation's politics doomed the CFBC to failure. My purpose is to place in national context the important developments and personalities of Florida's most important environmental controversy. ^ The methodology involved a series of interviews with the most important actors in the canal drama and the environmental movement. Also utilized were regional collections in Florida Public Libraries, the Florida State Archives, personal papers housed at the University of Florida and Corps of Engineers documents. Results showed a clear connection between Florida activism and national environmental policy through the influence of key individuals. I concluded that the CFBC acted as a catalyst to Florida's environmental movement, serving as an indicator of a larger political change from the New Deal coalition to the Republican realignment of 1968. ^

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Lineup procedures have recently garnered extensive empirical attention, in an effort to reduce the number of mistaken identifications that plague the criminal justice system. Relatively little attention, however, has been paid to the influence of the lineup constructor or the lineup construction technique on the quality of the lineup. This study examined whether the cross-race effect has an influence on the quality of lineups constructed using a match-to-suspect or match-to-description technique in a series of three phases. Participants generated descriptions of same- and other-race targets in Phase 1, which were used in Phase 2. In Phase 2, participants were asked to create lineups for own-race targets and other-race targets using one of two techniques. The lineups created in this phase were examined for lineup quality in Phase 3 by calculating lineup fairness assessments through the use of a mock witness paradigm. ^ Overall, the results of these experiment phases suggest that the race of those involved in the lineup construction process influences lineups. There was no difference in witness description accuracy in Phase 1, which ran counter to predictions based on the cross-race effect. The cross-race effect was observed, however, in Phases 2 and 3. The lineup construction technique used also influenced several of the process measures, selection estimates, and fairness judgments in Phase 2. Interestingly, the presence of the cross-race effect was in the opposite direction as predicted for some measures in both phases. In Phase 2, the cross-race effect was as predicted for number of foils viewed, but in the opposite direction for average time spent viewing each foil. In Phase 3, the cross-race effect was in the opposite direction than predicted, with higher levels of lineup fairness in other-race lineups. The practical implications of these findings are discussed in relation to lineup fairness within the legal system. ^

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Dust attenuation affects nearly all observational aspects of galaxy evolution, yet very little is known about the form of the dust-attenuation law in the distant universe. Here, we model the spectral energy distributions of galaxies at z ~ 1.5–3 from CANDELS with rest-frame UV to near-IR imaging under different assumptions about the dust law, and compare the amount of inferred attenuated light with the observed infrared (IR) luminosities. Some individual galaxies show strong Bayesian evidence in preference of one dust law over another, and this preference agrees with their observed location on the plane of infrared excess (IRX, L_TIR/L_UV) and UV slope (β). We generalize the shape of the dust law with an empirical model, A_ λ,σ =E(B-V)k_ λ (λ / λ v)^ σ where k_λ is the dust law of Calzetti et al., and show that there exists a correlation between the color excess E(B-V) and tilt δ with δ =(0.62±0.05)log(E(B-V))+(0.26±0.02). Galaxies with high color excess have a shallower, starburst-like law, and those with low color excess have a steeper, SMC-like law. Surprisingly, the galaxies in our sample show no correlation between the shape of the dust law and stellar mass, star formation rate, or β. The change in the dust law with color excess is consistent with a model where attenuation is caused by scattering, a mixed star–dust geometry, and/or trends with stellar population age, metallicity, and dust grain size. This rest-frame UV-to-near-IR method shows potential to constrain the dust law at even higher redshifts (z>3).

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Steady laminar flow of a non-Newtonian fluid based on couple stress fluid theory, through narrow tubes of varying cross-sections has been studied theoretically. Asymptotic solutions are obtained for the basic equations and the expressions for the velocity field and the wall shear stress are derived for a general cross-section. Computation and discussions are carried out for the geometries which occur in the context of physiological flows or in particular blood flows. The tapered tubes and constricted tubes are of special importance. It is observed that increase in certain parameters results in erratic flow behaviour proximal to the constricted areas which is further enhanced by the increase in the geometric parameters. This elucidates the implications of the flow in the development of vascular lesions.

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We calculate the in-medium nucleon-nucleon scattering cross sections from the G-matrix using the Dirac-Brueckner-Hartree-Fock (DBHF) approach. And we investigate the influence of the different representations of the G-matrix to the cross sections, the difference of which is mainly from the different effective masses.

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Charts and graphs of cross sections from Brown’s ditch culvert to the main drain, cross sections from the feeder on the road allowance between lots 26 and 27 in the 5th concession of Humberstone, Cross sections of the main drain from Lyons Creek culvert to the road allowance between lots 7 and 8 in Wainfleet and cross selections of the old ditch on the west side of the road allowance between lots 17 and 18 in the 3rd concession in Wainfleet (8 pages, hand drawn), n.d.

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Within a QCD-based eikonal model with a dynamical infrared gluon mass scale we discuss how the small x behavior of the gluon distribution function at moderate Q(2) is directly related to the rise of total hadronic cross-sections. In this model the rise of total cross-sections is driven by gluon-gluon semihard scattering processes, where the behavior of the small x gluon distribtuion function exhibits the power law xg(x, Q(2)) = h(Q(2))x(-epsilon). Assuming that the Q(2) scale is proportional to the dynamical gluon mass one, we show that the values of h(Q(2)) obtained in this model are compatible with an earlier result based on a specific nonperturbative Pomeron model. We discuss the implications of this picture for the behavior of input valence-like gluon distributions at low resolution scales.

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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Within a QCD-based eikonal model with a dynamical infrared gluon mass scale we discuss how the small x behavior of the gluon distribution function at moderate Q 2 is directly related to the rise of total hadronic cross-sections. In this model the rise of total cross-sections is driven by gluon-gluon semihard scattering processes, where the behavior of the small x gluon distribution function exhibits the power law xg(x, Q 2) = h(Q 2)x( -∈). Assuming that the Q 2 scale is proportional to the dynamical gluon mass one, we show that the values of h(Q 2) obtained in this model are compatible with an earlier result based on a specific nonperturbative Pomeron model. We discuss the implications of this picture for the behavior of input valence-like gluon distributions at low resolution scales. © 2008 World Scientific Publishing Company.