Neural networks and statistical analysis for classification of corneal videokeratography maps based on Zernike coefficients: a quantitative comparison

PURPOSE: The main goal of this study was to develop and compare two different techniques for classification of specific types of corneal shapes when Zernike coefficients are used as inputs. A feed-forward artificial Neural Network (NN) and discriminant analysis (DA) techniques were used. METHODS: The inputs both for the NN and DA were the first 15 standard Zernike coefficients for 80 previously classified corneal elevation data files from an Eyesys System 2000 Videokeratograph (VK), installed at the Departamento de Oftalmologia of the Escola Paulista de Medicina, São Paulo. The NN had 5 output neurons which were associated with 5 typical corneal shapes: keratoconus, with-the-rule astigmatism, against-the-rule astigmatism, "regular" or "normal" shape and post-PRK. RESULTS: The NN and DA responses were statistically analyzed in terms of precision ([true positive+true negative]/total number of cases). Mean overall results for all cases for the NN and DA techniques were, respectively, 94% and 84.8%. CONCLUSION: Although we used a relatively small database, results obtained in the present study indicate that Zernike polynomials as descriptors of corneal shape may be a reliable parameter as input data for diagnostic automation of VK maps, using either NN or DA.

Changes in parents' and self-reports of behavioral problems in Brazilian adolescents after behavioral treatment with urine alarm for nocturnal enuresis

PURPOSE: Compare parents' reports of youth problems (PRYP) with adolescent problems self-reports (APSR) pre/post behavioral treatment of nocturnal enuresis (NE) based on the use of a urine alarm. MATERIALS AND METHODS: Adolescents (N = 19) with mono-symptomatic (primary or secondary) nocturnal enuresis group treatment for 40 weeks. Discharge criterion was established as 8 weeks with consecutive dry nights. PRYP and APSR were scored by the Child Behavior Checklist (CBCL) and Youth Self-Report (YSR). RESULTS: Pre-treatment data: 1) Higher number of clinical cases based on parent report than on self-report for Internalizing Problems (IP) (13/19 vs. 4/19), Externalizing Problems (EP) (7/19 vs. 5/19) and Total Problem (TP) (11/19 vs. 5/19); 2) Mean PRYP scores for IP (60.8) and TP (61) were within the deviant range (T score ≥ 60); while mean PRYP scores for EP (57.4) and mean APSR scores (IP = 52.4, EP = 49.5, TP = 52.4) were within the normal range. Difference between PRYP' and APSR' scores was significant. Post treatment data: 1) Discharge for majority of the participants (16/19); 2) Reduction in the number of clinical cases on parental evaluation: 9/19 adolescents remained within clinical range for IP, 2/19 for EP, and 7/19 for TP. 3) All post-treatment mean scores were within the normal range; the difference between pre and post evaluation scores was significant for PRYP. CONCLUSIONS: The behavioral treatment based on the use of urine alarm is effective for adolescents with mono-symptomatic (primary and secondary) nocturnal enuresis. The study favors the hypothesis that enuresis is a cause, not a consequence, of other behavioral problems.

Molecular phylogeny of advanced snakes (Serpentes, Caenophidia) with an emphasis on South American Xenodontines: a revised classification and descriptions of new taxa

We present a molecular phylogenetic analysis of caenophidian (advanced) snakes using sequences from two mitochondrial genes (12S and 16S rRNA) and one nuclear (c-mos) gene (1681 total base pairs), and with 131 terminal taxa sampled from throughout all major caenophidian lineages but focussing on Neotropical xenodontines. Direct optimization parsimony analysis resulted in a well-resolved phylogenetic tree, which corroborates some clades identified in previous analyses and suggests new hypotheses for the composition and relationships of others. The major salient points of our analysis are: (1) placement of Acrochordus, Xenodermatids, and Pareatids as successive outgroups to all remaining caenophidians (including viperids, elapids, atractaspidids, and all other "colubrid" groups); (2) within the latter group, viperids and homalopsids are sucessive sister clades to all remaining snakes; (3) the following monophyletic clades within crown group caenophidians: Afro-Asian psammophiids (including Mimophis from Madagascar), Elapidae (including hydrophiines but excluding Homoroselaps), Pseudoxyrhophiinae, Colubrinae, Natricinae, Dipsadinae, and Xenodontinae. Homoroselaps is associated with atractaspidids. Our analysis suggests some taxonomic changes within xenodontines, including new taxonomy for Alsophis elegans, Liophis amarali, and further taxonomic changes within Xenodontini and the West Indian radiation of xenodontines. Based on our molecular analysis, we present a revised classification for caenophidians and provide morphological diagnoses for many of the included clades; we also highlight groups where much more work is needed. We name as new two higher taxonomic clades within Caenophidia, one new subfamily within Dipsadidae, and, within Xenodontinae five new tribes, six new genera and two resurrected genera. We synonymize Xenoxybelis and Pseudablabes with Philodryas; Erythrolamprus with Liophis; and Lystrophis and Waglerophis with Xenodon.

Causas mal definidas de morte e óbitos sem assistência

OBJETIVOS: Este trabalho estuda a distribuição dos óbitos por causas mal definidas no Brasil, no ano de 2003, entre as quais identifica a proporção de mortes sem assistência. MÉTODOS: Os dados provieram do Sistema de Informações Sobre Mortalidade, coordenado pelo Ministério da Saúde. As causas mal definidas de morte compreenderam as incluídas no "Capítulo XVIII - Sintomas, sinais e achados anormais de exames clínicos e de laboratório não classificados em outra parte" da Classificação Estatística Internacional de Doenças e Problemas Relacionados à Saúde, décima revisão, capítulo este no qual a categoria R98 identificava a "morte sem assistência". RESULTADOS: No Brasil, em 2003, a causa básica de 13,3% dos óbitos foi identificada como mal definida, sendo que as proporções maiores ocorreram nas Regiões Nordeste e Norte. Do total de causas mal definidas no país, 53,3% corresponderam a mortes sem assistência, proporção esta que superou 70% nos Estados do Maranhão, Piauí, Rio Grande do Norte, Pernambuco, Bahia, Paraíba e Alagoas. CONCLUSÃO: Dada a estrutura descentralizada para o levantamento dos óbitos no país, identifica-se a maior responsabilidade dos municípios e, em seguida, dos Estados para o aprimoramento da qualidade das estatísticas de mortalidade.

O papel das Classificações da OMS - CID e CIF nas definições de deficiência e incapacidade

A Organização Mundial de Saúde tem hoje duas classificações de referência para a descrição dos estados de saúde: a Classificação Estatística Internacional de Doenças e Problemas Relacionados à Saúde, que corresponde à décima revisão da Classificação Internacional de Doenças (CID-10) e a Classificação Internacional de Funcionalidade, Incapacidade e Saúde (CIF). A utilização da CIF vem sendo aguardada com grande expectativa pelas organizações de pessoas com deficiências e instituições relacionadas. A falta de definição clara de "deficiência" ou "incapacidade" tem sido apontada como um impedimento para a promoção de saúde de pessoas com deficiência. É importante que essas definições, especialmente no âmbito legislativo e regulamentar, sejam consistentes e se fundamentem num modelo coerente sobre o processo que origina as situações de incapacidade. Este artigo tem como objetivo apresentar elementos da CID-10 e da CIF, e o papel que desempenham para definir deficiência e incapacidade. Os componentes da CIF podem contribuir para diferentes campos de aplicabilidade no que diz respeito ao entendimento das definições de deficiência ou incapacidade a partir do conceito de funcionalidade e dos fatores contextuais.

A new classification of foods based on the extent and purpose of their processing

This paper describes a new food classification which assigns foodstuffs according to the extent and purpose of the industrial processing applied to them. Three main groups are defined: unprocessed or minimally processed foods (group 1), processed culinary and food industry ingredients (group 2), and ultra-processed food products (group 3). The use of this classification is illustrated by applying it to data collected in the Brazilian Household Budget Survey which was conducted in 2002/2003 through a probabilistic sample of 48,470 Brazilian households. The average daily food availability was 1,792 kcal/person being 42.5% from group 1 (mostly rice and beans and meat and milk), 37.5% from group 2 (mostly vegetable oils, sugar, and flours), and 20% from group 3 (mostly breads, biscuits, sweets, soft drinks, and sausages). The share of group 3 foods increased with income, and represented almost one third of all calories in higher income households. The impact of the replacement of group 1 foods and group 2 ingredients by group 3 products on the overall quality of the diet, eating patterns and health is discussed.

O papel das Classificações da OMS-CID e CIF nas definições de deficiência e incapacidade

A Organização Mundial de Saúde tem hoje duas classificações de referência para a descrição dos estados de saúde: a Classificação Estatística Internacional de Doenças e Problemas Relacionados à Saúde, que corresponde à décima revisão da Classificação Internacional de Doenças (CID-10) e a Classificação Internacional de Funcionalidade, Incapacidade e Saúde (CIF). A utilização da CIF vem sendo aguardada com grande expectativa pelas organizações de pessoas com deficiências e instituições relacionadas. A falta de definição clara de "deficiência" ou "incapacidade" tem sido apontada como um impedimento para a promoção de saúde de pessoas com deficiência. É importante que essas definições, especialmente no âmbito legislativo e regulamentar, sejam consistentes e se fundamentem num modelo coerente sobre o processo que origina as situações de incapacidade. Este artigo tem como objetivo apresentar elementos da CID-10 e da CIF, e o papel que desempenham para definir deficiência e incapacidade. Os componentes da CIF podem contribuir para diferentes campos de aplicabilidade no que diz respeito ao entendimento das definições de deficiência ou incapacidade a partir do conceito de funcionalidade e dos fatores contextuais

A mortalidade de idosos no Brasil: a questão das causas mal definidas

O envelhecimento populacional é um fato marcante da transição demográfica. O estudo das causas básicas em idosos permite visualizar seu perfil epidemiológico, embora possa ser prejudicado pela alta proporção de causas mal definidas. O objetivo deste trabalho é descrever a mortalidade dos idosos por essas causas no Brasil. A fonte dos dados foi o Sistema de Informações sobre Mortalidade do Ministério da Saúde.Entre as variáveis, a principal modalidade foi a causa básica mal definida [ Capítulo XVIII da Classificação Estatística Internacional de Doenças e Problemas Relacionados à Saúde-Décima Revisão (CID-10)]. O decréscimo desses óbitos em idosos foi de 35 por cento entre 1996 e 2005.Considerando os óbitos de 60 a 69 anos e os de 80 e mais anos, as proporções de mal definidos aumentaram em 9,9 por cento e 14,8 por cento, respectivamente, no ano de 2005. Métodos visando a sua diminuição são sugeridos, salientando-se que o fato mais importante é o de os médicos preencherem adequadamente as declarações de óbito- com as reais causas básicas, conseqüênciais e terminais-, objetivo maior dos estudiosos

Mortes maternas e mortes por causas maternas

Ao mensurar-se mortalidade materna, é necessário distinguir ' mortes por causas maternas' e 'mortes maternas' Para a Organização Mundial da Saúde-OMS-,mortes maternas são as que ocorrem na gestação, no parto e até 42 dias após o parto; e mortes por causas maternas englobam as causas classificadas no Capítulo XV da Classificação Estatística Internacional de Doenças e Problemas Relacionados à Saúde, Décima Revisão (CID-10), incluindo as ocorridas quando passados 42 dias do parto. Apresentam-se resultados da investigação de mortes femininas em idade fértil-10 a 49 anos- nas capitais de Estados e no Distrito Federal do Brasil, em 2002. Adotou-se a metodologia RAMOS, comparando-se as causas básicas das declarações de óbito originais com as das declarações preenchidas após o resgate de informações, obtidas em entrevistas domiciliares e prontuários. Entre as mortes por causas maternas originais, 15,9 por cento não eram mortes maternas, de acordo com a definição da OMS. Houve, concomitantemente, subenumeração de mortes maternas. Sugestões são feitas para melhorar o preenchimento das declarações de óbito e inclusão de novas categorias na CID-10, visando melhorar a informação das causas maternas

Classification of breast masses using a committee machine of artificial neural networks

This work proposes a new approach using a committee machine of artificial neural networks to classify masses found in mammograms as benign or malignant. Three shape factors, three edge-sharpness measures, and 14 texture measures are used for the classification of 20 regions of interest (ROIs) related to malignant tumors and 37 ROIs related to benign masses. A group of multilayer perceptrons (MLPs) is employed as a committee machine of neural network classifiers. The classification results are reached by combining the responses of the individual classifiers. Experiments involving changes in the learning algorithm of the committee machine are conducted. The classification accuracy is evaluated using the area A. under the receiver operating characteristics (ROC) curve. The A, result for the committee machine is compared with the A, results obtained using MLPs and single-layer perceptrons (SLPs), as well as a linear discriminant analysis (LDA) classifier Tests are carried out using the student's t-distribution. The committee machine classifier outperforms the MLP SLP, and LDA classifiers in the following cases: with the shape measure of spiculation index, the A, values of the four methods are, in order 0.93, 0.84, 0.75, and 0.76; and with the edge-sharpness measure of acutance, the values are 0.79, 0.70, 0.69, and 0.74. Although the features with which improvement is obtained with the committee machines are not the same as those that provided the maximal value of A(z) (A(z) = 0.99 with some shape features, with or without the committee machine), they correspond to features that are not critically dependent on the accuracy of the boundaries of the masses, which is an important result. (c) 2008 SPIE and IS&T.

Combining Legendre's Polynomials and Genetic Algorithm in the Solution of Nonlinear Initial-Value Problems

This work develops a method for solving ordinary differential equations, that is, initial-value problems, with solutions approximated by using Legendre's polynomials. An iterative procedure for the adjustment of the polynomial coefficients is developed, based on the genetic algorithm. This procedure is applied to several examples providing comparisons between its results and the best polynomial fitting when numerical solutions by the traditional Runge-Kutta or Adams methods are available. The resulting algorithm provides reliable solutions even if the numerical solutions are not available, that is, when the mass matrix is singular or the equation produces unstable running processes.

Cost-effectiveness analysis of PCR for the rapid diagnosis of pulmonary tuberculosis

Background: Tuberculosis is one of the most prominent health problems in the world, causing 1.75 million deaths each year. Rapid clinical diagnosis is important in patients who have comorbidities such as Human Immunodeficiency Virus (HIV) infection. Direct microscopy has low sensitivity and culture takes 3 to 6 weeks [1-3]. Therefore, new tools for TB diagnosis are necessary, especially in health settings with a high prevalence of HIV/TB co-infection. Methods: In a public reference TB/HIV hospital in Brazil, we compared the cost-effectiveness of diagnostic strategies for diagnosis of pulmonary TB: Acid fast bacilli smear microscopy by Ziehl-Neelsen staining (AFB smear) plus culture and AFB smear plus colorimetric test (PCR dot-blot). From May 2003 to May 2004, sputum was collected consecutively from PTB suspects attending the Parthenon Reference Hospital. Sputum samples were examined by AFB smear, culture, and PCR dot-blot. The gold standard was a positive culture combined with the definition of clinical PTB. Cost analysis included health services and patient costs. Results: The AFB smear plus PCR dot-blot require the lowest laboratory investment for equipment (US$ 20,000). The total screening costs are 3.8 times for AFB smear plus culture versus for AFB smear plus PCR dot blot costs (US$ 5,635,760 versus US$ 1,498, 660). Costs per correctly diagnosed case were US$ 50,773 and US$ 13,749 for AFB smear plus culture and AFB smear plus PCR dot-blot, respectively. AFB smear plus PCR dot-blot was more cost-effective than AFB smear plus culture, when the cost of treating all correctly diagnosed cases was considered. The cost of returning patients, which are not treated due to a negative result, to the health service, was higher in AFB smear plus culture than for AFB smear plus PCR dot-blot, US$ 374,778,045 and US$ 110,849,055, respectively. Conclusion: AFB smear associated with PCR dot-blot associated has the potential to be a cost-effective tool in the fight against PTB for patients attended in the TB/HIV reference hospital.

Automated supervised classification of variable stars in the CoRoT programme Method and application to the first four exoplanet fields

Aims. In this work, we describe the pipeline for the fast supervised classification of light curves observed by the CoRoT exoplanet CCDs. We present the classification results obtained for the first four measured fields, which represent a one-year in-orbit operation. Methods. The basis of the adopted supervised classification methodology has been described in detail in a previous paper, as is its application to the OGLE database. Here, we present the modifications of the algorithms and of the training set to optimize the performance when applied to the CoRoT data. Results. Classification results are presented for the observed fields IRa01, SRc01, LRc01, and LRa01 of the CoRoT mission. Statistics on the number of variables and the number of objects per class are given and typical light curves of high-probability candidates are shown. We also report on new stellar variability types discovered in the CoRoT data. The full classification results are publicly available.

TESTING STATISTICAL HYPOTHESIS ON RANDOM TREES AND APPLICATIONS TO THE PROTEIN CLASSIFICATION PROBLEM

Efficient automatic protein classification is of central importance in genomic annotation. As an independent way to check the reliability of the classification, we propose a statistical approach to test if two sets of protein domain sequences coming from two families of the Pfam database are significantly different. We model protein sequences as realizations of Variable Length Markov Chains (VLMC) and we use the context trees as a signature of each protein family. Our approach is based on a Kolmogorov-Smirnov-type goodness-of-fit test proposed by Balding et at. [Limit theorems for sequences of random trees (2008), DOI: 10.1007/s11749-008-0092-z]. The test statistic is a supremum over the space of trees of a function of the two samples; its computation grows, in principle, exponentially fast with the maximal number of nodes of the potential trees. We show how to transform this problem into a max-flow over a related graph which can be solved using a Ford-Fulkerson algorithm in polynomial time on that number. We apply the test to 10 randomly chosen protein domain families from the seed of Pfam-A database (high quality, manually curated families). The test shows that the distributions of context trees coming from different families are significantly different. We emphasize that this is a novel mathematical approach to validate the automatic clustering of sequences in any context. We also study the performance of the test via simulations on Galton-Watson related processes.

Multiclass Hammersley-Aldous-Diaconis process and multiclass-customer queues

In the Hammersley-Aldous-Diaconis process, infinitely many particles sit in R and at most one particle is allowed at each position. A particle at x, whose nearest neighbor to the right is at y, jumps at rate y - x to a position uniformly distributed in the interval (x, y). The basic coupling between trajectories with different initial configuration induces a process with different classes of particles. We show that the invariant measures for the two-class process can be obtained as follows. First, a stationary M/M/1 queue is constructed as a function of two homogeneous Poisson processes, the arrivals with rate, and the (attempted) services with rate rho > lambda Then put first class particles at the instants of departures (effective services) and second class particles at the instants of unused services. The procedure is generalized for the n-class case by using n - 1 queues in tandem with n - 1 priority types of customers. A multi-line process is introduced; it consists of a coupling (different from Liggett's basic coupling), having as invariant measure the product of Poisson processes. The definition of the multi-line process involves the dual points of the space-time Poisson process used in the graphical construction of the reversed process. The coupled process is a transformation of the multi-line process and its invariant measure is the transformation described above of the product measure.