959 resultados para Minimum eigenvalue


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This final report contains two separate reports which describe the retroreflectivity levels of various traffic signs and pavement markings on the Iowa primary road system. The data was collected in the fall/winter of 1994 and given to the Federal Highway Administration in March of 1995. This information is currently being combined with similar information from other jurisdictions across the country for the purpose of determining the impact of mandated minimum retroreflectivity levels. The FHWA will be releasing their report sometime in 1996. In October 1992, Congress mandated (Public Law 102-388) the Secretary of Transportation to revise the Manual of Uniform Traffic Control Devices to include a minimum level of retroreflectivity for pavement markings and traffic signs which shall apply to all roads open to public travel. In 1994, the FHWA initiated research studies to determine the retroreflectivity levels which currently exist for signs and markings in an attempt to develop standards which are reasonable to implement. The Iowa Department of Transportation participated in both of the studies and the final reports are included. After compilation and analysis of the collected retroreflectivity data, the FHWA will propose the new MUTCD standards through the federal rule making process. It is estimated that the actual MUTCD change will occur sometime in late 1997 or early 1998.

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Individuals with disabilities have civil rights protection similar to that provided to individuals on the basis of race, sex, national origin, and religion. The advent of the Americans with Disabilities Act has improved these protections and brought this issue into the forefront. This book is not intended to be a legal translation of state or federal laws. Its purpose is to assist people with disabilities in understanding their rights. Please consult the Code of Iowa, the appropriate federal laws or an attorney if you need a legal interpretation.

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Markets, in the real world, are not efficient zero-sum games where hypotheses of the CAPM are fulfilled. Then, it is easy to conclude the market portfolio is not located on Markowitz"s efficient frontier, and passive investments (and indexing) are not optimal but biased. In this paper, we define and analyze biases suffered by passive investors: the sample, construction, efficiency and active biases and tracking error are presented. We propose Minimum Risk Indices (MRI) as an alternative to deal with to market index biases, and to provide investors with portfolios closer to the efficient frontier, that is, more optimal investment possibilities. MRI (using a Parametric Value-at-Risk Minimization approach) are calculated for three stock markets achieving interesting results. Our indices are less risky and more profitable than current Market Indices in the Argentinean and Spanish markets, facing that way the Efficient Market Hypothesis. Two innovations must be outlined: an error dimension has been included in the backtesting and the Sharpe"s Ratio has been used to select the"best" MRI

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We answer the following question: given any n∈ℕ, which is the minimum number of endpoints en of a tree admitting a zero-entropy map f with a periodic orbit of period n? We prove that en=s1s2…sk−∑i=2ksisi+1…sk, where n=s1s2…sk is the decomposition of n into a product of primes such that si≤si+1 for 1≤ie, then the topological entropy of f is positive

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Contrast enhancement is an image processing technique where the objective is to preprocess the image so that relevant information can be either seen or further processed more reliably. These techniques are typically applied when the image itself or the device used for image reproduction provides poor visibility and distinguishability of different regions of interest inthe image. In most studies, the emphasis is on the visualization of image data,but this human observer biased goal often results to images which are not optimal for automated processing. The main contribution of this study is to express the contrast enhancement as a mapping from N-channel image data to 1-channel gray-level image, and to devise a projection method which results to an image with minimal error to the correct contrast image. The projection, the minimum-error contrast image, possess the optimal contrast between the regions of interest in the image. The method is based on estimation of the probability density distributions of the region values, and it employs Bayesian inference to establish the minimum error projection.

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INTRODUCTION: Periprosthetic femur fracture (PFF) is a serious complication after total hip arthroplasty that can be treated using different internal fixation devices. However, the outcomes with curved non-locking plates with eccentric holes in this indication have not been reported previously. The objectives of this study were to determine: (1) the union rate; (2) the complication rate; (3) autonomy in a group of patients with a Vancouver type B PFF who were treated with this plate. HYPOTHESIS: Use of this plate results in a high union rate with minimal mechanical complications. MATERIALS AND METHODS: Forty-three patients with a mean age of 79 years±13 (41-98) who had undergone fixation of Vancouver type B PFF with this plate between 2002 and 2007 were included in the study. The time to union and Parker Mobility Score were evaluated. The revision-free survival (all causes) was calculated using Kaplan-Meier analysis. The average follow-up was 42 months±20 (16-90). RESULTS: Union was obtained in all patients in a mean of 2.4 months±0.6 (2-4). One patient had varus malunion of the femur. The Parker Mobility Score decreased from 5.93±1.94 (2-9) to 4.93±1.8 (1-9) (P=0.01). Two patients required a surgical revision: one for an infection after 4.5 years and one for stem loosening. The survival of the femoral stem 5 years after fracture fixation was 83.3%±12.6%. CONCLUSION: Use of a curved plate with eccentric holes for treating type B PFF led to a high union rate and a low number of fixation-related complications. However, PFF remains a serious complication of hip arthroplasty that is accompanied by high morbidity and mortality rates. LEVEL OF EVIDENCE: Retrospective study, level IV.

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La fracture périprothétique du fémur (FPF) représente une complication sérieuse des arthroplasties de hanche. Différents matériels d'ostéosynthèse ont été utilisés pour l'ostéosynthèse des FPFs. Toutefois, aucune étude n'a rapporté les résultats obtenus avec une plaque anatomique non-verrouillée avec des trous excentrés. Les buts de ce travail étaient de présenter 1) le taux de consolidation des FPF traitées par cet implant, 2) les caractéristiques péri-opératoires 3) le taux de complications, et 4) les résultats en terme d'autonomie obtenus après le traitement des FPF du groupe B selon Vancouver avec une plaque anatomique à trous excentrés. Hypothèse L'utilisation de cette plaque permet d'obtenir un taux élevé de consolidation avec un minimum de complications mécaniques. Matériels et Méthodes Quarante-trois patients, d'âge moyen 79 ans ± 13 (41 - 98), qui ont été traités pour une ostéosynthèse d'une FPF de type B selon Vancouver avec cette plaque entre 2002 et 2007 ont été inclus. Les patients ont été classifiées selon les scores ASA et de Charnley. Le temps opératoire, les pertes sanguines chirurgicales, le nombre de transfusion, la durée d'hospitalisation, le délai de consolidation, le lieu de vie ainsi que l'autonomie (score de Parker) ont été évalués. Le taux de survie sans révision a été calculé par la méthode de Kaplan-Meier. Le recul moyen est de 42 mois ± 20 (min - max : 16 - 90). Résultats La consolidation a été obtenue chez tous les patients avec un délai moyen de 2,4 mois ± 0,6 (2-4). 1 patient avec un cal vicieux en varus était à déplorer. Le score de Parker a diminué de 5,93 ± 1,94 (2-9) à 4,93 ± 1,8 (1- 9) (p = 0.01). 2 révisions chirurgicales ont été nécessaires sur la série. Le taux de survie à 5 ans des prothèses après ostéosynthèse de la FPF était de 83,3 % ± 12,6 %. Conclusion Cette plaque anatomique avec trous excentrés permet le traitement des FPF du type B et garantit une consolidation de la fracture avec un faible taux de complications liés à l'ostéosynthèse. Toutefois, les FPF représentent une complication sérieuse des arthroplasties de hanche assortie d'un fort taux de morbidités et de mortalité.

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Markets, in the real world, are not efficient zero-sum games where hypotheses of the CAPM are fulfilled. Then, it is easy to conclude the market portfolio is not located on Markowitz"s efficient frontier, and passive investments (and indexing) are not optimal but biased. In this paper, we define and analyze biases suffered by passive investors: the sample, construction, efficiency and active biases and tracking error are presented. We propose Minimum Risk Indices (MRI) as an alternative to deal with to market index biases, and to provide investors with portfolios closer to the efficient frontier, that is, more optimal investment possibilities. MRI (using a Parametric Value-at-Risk Minimization approach) are calculated for three stock markets achieving interesting results. Our indices are less risky and more profitable than current Market Indices in the Argentinean and Spanish markets, facing that way the Efficient Market Hypothesis. Two innovations must be outlined: an error dimension has been included in the backtesting and the Sharpe"s Ratio has been used to select the"best" MRI

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The set of initial conditions for which the pseudoclassical evolution algorithm (and minimality conservation) is verified for Hamiltonians of degrees N (N>2) is explicitly determined through a class of restrictions for the corresponding classical trajectories, and it is proved to be at most denumerable. Thus these algorithms are verified if and only if the system is quadratic except for a set of measure zero. The possibility of time-dependent a-equivalence classes is studied and its physical interpretation is presented. The implied equivalence of the pseudoclassical and Ehrenfest algorithms and their relationship with minimality conservation is discussed in detail. Also, the explicit derivation of the general unitary operator which linearly transforms minimum-uncertainty states leads to the derivation, among others, of operators with a general geometrical interpretation in phase space, such as rotations (parity, Fourier).

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The chemical treatment evaluation in the field to control post-harvest fruit anthracnose (Colletotrichum gloeosporioides) requires a suitable disease incidence assessment on harvested papaya (Carica papaya) fruits. The minimum number of papaya fruit harvests was determined for valid treatment comparison in field trials for anthracnose chemical control. Repeatability analysis was done using previously published data. The coefficient determination (R²) estimate range, using four methods, and based on means of 12 assessment times, was 92.58 < R² < 94.45%. The number of assessment times required for R²=90% varied from seven to nine. The R² values of 85.1 < R² < 91.3% estimated by ANOVA suggested that any seven successive assessment times were sufficient for treatment comparison.

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To maintain a competitive development of the Brazilian aviculture, some measures must be taken to enable the identification and reduction of risks to the health of birds, as well as for the physical environment. Therefore, the aim of this study was to evaluate the effectiveness of three different systems of minimum ventilation (positive pressure - SVMP, negative pressure - SVMN and natural ventilation - SVMNat) in the air quality during the first 21 days of life of broiler chicks, during winter. Three points were selected along the length to verify ammonia, carbon monoxide and oxygen concentrations at 3a.m., 9a.m., 3p.m. and 9p.m., by the respiration level of birds and workers. The averages of pollutant gases did not exceed the tolerance levels for the three minimum ventilation systems evaluated, which is 20 and 10ppm for the birds level and 20 and 39ppm for the workers level, for ammonia and carbon monoxide, respectively. It was evident that the minimum ventilation systems were appropriately sized for the required minimum ambient air renovation, in respect to ventilation rates applied for the SVMN and SVMP systems, and with air velocity at levels that do not stress the chicks, including for the SVMNat. The three studied systems of minimum ventilation allowed the birds to externalize their productive performance, with values close to the ones considered satisfactory for all evaluated parameters, in accordance with the Brazilian aviculture standards.

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ABSTRACT This study aimed to develop a methodology based on multivariate statistical analysis of principal components and cluster analysis, in order to identify the most representative variables in studies of minimum streamflow regionalization, and to optimize the identification of the hydrologically homogeneous regions for the Doce river basin. Ten variables were used, referring to the river basin climatic and morphometric characteristics. These variables were individualized for each of the 61 gauging stations. Three dependent variables that are indicative of minimum streamflow (Q7,10, Q90 and Q95). And seven independent variables that concern to climatic and morphometric characteristics of the basin (total annual rainfall – Pa; total semiannual rainfall of the dry and of the rainy season – Pss and Psc; watershed drainage area – Ad; length of the main river – Lp; total length of the rivers – Lt; and average watershed slope – SL). The results of the principal component analysis pointed out that the variable SL was the least representative for the study, and so it was discarded. The most representative independent variables were Ad and Psc. The best divisions of hydrologically homogeneous regions for the three studied flow characteristics were obtained using the Mahalanobis similarity matrix and the complete linkage clustering method. The cluster analysis enabled the identification of four hydrologically homogeneous regions in the Doce river basin.