Patricia M. Valenzuela

Genetic design of biologically inspired receptive fields for neural pattern recognition

This paper proposes a new method for the design, through simulated evolution, of biologically inspired receptive fields in feedforward neural networks (NNs). The method is intended to enhance pattern recognition performance by creating new neural architectures specifically tuned for a particular pattern recognition problem. It proposes a combined neural architecture composed of two networks in cascade: a feature extraction network (FEN) followed by a neural classifier. The FEN is composed of several layers with receptive fields constructed by additive superposition of excitatory and inhibitory fields. A genetic algorithm (GA) is used to select receptive field parameters to improve classification performance. The parameters are receptive field size, orientation, and bias as well as the number of different receptive fields in each layer. Based on a random initial population where each individual represents a different neural architecture, the GA creates new enhanced individuals. The method is applied to handwritten digit classification and face recognition. In both problems, results show strong dependency between NN classification performance and receptive field architecture. GA selected parameters of the receptive fields produced improvements in the classification performance on the test set up to 90.8% for the problem of handwritten digit classification and up to 84.2% for the face recognition problem. On the same test sets, results were compared advantageously to standard feedforward multilayer perceptron (MLP) NNs where receptive fields are not explicitly defined. The MLP reached a maximum classification performance of 84.9% and 77.5% in both problems, respectively.

Environmental pediatrics: an emerging issue

OBJECTIVE To review the most relevant articles regarding environmental pediatrics, its potential effects on health, and especially its advances in prevention. SOURCES A literature search was conducted using MEDLINE/PubMed and SciELO databases. Articles from 1990 to 2010 were reviewed, in addition to book chapters related to environmental pediatrics. SUMMARY OF THE FINDINGS There is a significant variety of factors that make children highly vulnerable to environmental hazard exposure, which are mainly associated with childrens comparatively greater consumption of water, food, and air in relation to body weight. According to the World Health Organization, every year more than 3 million children under the age of 5 die because of environment-related conditions. Approximately 30 to 40% of pediatric diseases are related to environmental factors. Children are constantly exposed to various environmental health hazards, among which the following stand out: contaminated water, lack of adequate sanitation facilities, air pollution, disease vectors, chemical hazards, injuries, and accidents. CONCLUSIONS Nowadays, pediatricians are challenged to address environmental pediatrics health care needs. The pediatric health history needs to be more comprehensive by adding pointed questions to help identify potential environmental risks. Awareness and understanding of the noxious effects of various environmental conditions and knowledge of the related prevention measures will result in timely and adequate interventions that will improve our childrens health and development.

Analysis of a learning assessment system for pediatric internship based upon objective structured clinical examination, clinical practice observation and written examination.

OBJECTIVE To describe and analyze three tools used in the assessment system applied to the pediatric internship over a 7-year period at the School of Medicine, Pontificia Universidad Católica de Chile, Santiago, Chile. METHODS Retrospective observational research design for the assessment modalities implemented in the pediatric internship from 2001 through 2007. The tools were as follows: objective structured clinical examination (OSCE), written examination and daily clinical practice observation guidelines (DCPOG). The assessment methods were applied to the sixth-year pediatric internship with a total of 697 students. Statistical analysis included a descriptive assessment, with correlation and simple linear and multiple regressions (ANOVA), Bonferroni test and Cronbachs alpha coefficient. Significance level was set at p < 0.05. RESULTS OSCE success scores were reached in 75.7+/-8%, with a better mean among females (p < 0.001). OSCE scores improved after the third year of implementation. Cronbachs alpha coefficient was 0.11-0.78. Written examination had a mean score of 79.8+/-10% and there were no sex differences. Mean DCPOG score was 97.1+/-3% and the results were better among females (p < 0.005). Correlation between the three assessment methods showed a moderate positive relationship except in the year of 2007, where the correlation was higher (p < 0.001). CONCLUSIONS Analysis of the learning assessment system was performed using OSCE, written examination and DCPOG, which are complementary to each other, and yielded good results.

Pediatria ambiental: um tema emergente

OBJECTIVE: To review the most relevant articles regarding environmental pediatrics, its potential effects on health, and especially its advances in prevention. SOURCES: A literature search was conducted using MEDLINE/PubMed and SciELO databases. Articles from 1990 to 2010 were reviewed, in addition to book chapters related to environmental pediatrics. SUMMARY OF THE FINDINGS: There is a significant variety of factors that make children highly vulnerable to environmental hazard exposure, which are mainly associated with children’s comparatively greater consumption of water, food, and air in relation to body weight. According to the World Health Organization, every year more than 3 million children under the age of 5 die because of environment-related conditions. Approximately 30 to 40% of pediatric diseases are related to environmental factors. Children are constantly exposed to various environmental health hazards, among which the following stand out: contaminated water, lack of adequate sanitation facilities, air pollution, disease vectors, chemical hazards, injuries, and accidents. CONCLUSIONS: Nowadays, pediatricians are challenged to address environmental pediatrics health care needs. The pediatric health history needs to be more comprehensive by adding pointed questions to help identify potential environmental risks. Awareness and understanding of the noxious effects of various environmental conditions and knowledge of the related prevention measures will result in timely and adequate interventions that will improve our children’s health and development.

Well-Being and Agency in Parents of Children With Congenital Heart Disease: A Survey in Chile

Background: Parents of children having congenital heart diseases (CHDs) develop symptoms of depression, distress, anxiety, and hopelessness more frequently than parents of healthy children. Associated with the described symptoms, parents may experience a lack of control and disempowerment, which decreases the parent’s agency, a construct from development studies, and which may have negative consequences on adherence to treatment. The primary aim of this study was to assess the effect of medical treatment on well-being and agency in parents of children having CHDs, in Chile, and to compare it with reference values. Methods: Forty parents of children having CHDs (before surgery and before hospital discharge) and 115 parents of healthy children were surveyed. The following scales were applied to this population: the General Health Questionnaire, the Basic Psychological Needs Scales, the Self-Determination Scale, the Beck Hopelessness Scale, and a socioeconomic survey. Results: Children’s surgery decreased parents’ hopelessness (3.13 ± 0.35 and 2.18 ± 0.40, P = .04), and no significant differences were found in the remaining scales. Parents of children with CHDs scored significantly worse than parents of healthy children on the General Health Questionnaire (13.82 ± 1.03 and 9.21 ± 0.64, P = .001). This difference was not found using the others scales. Conclusion: Children’s surgery has a positive effect on parent’s hopelessness, but it does not have any impact on their well-being nor agency. Parents of children with CHD have a decreased well-being compared to parents of healthy children but have a similar level of agency. Socioeconomic level and gender may influence this association.

International Perspectives: Chile

In the past 50 years, Chile has transitioned from an underdeveloped to a developing country with important improvements in health indicators. The creation of a National Health Service with hospitals and health centers across the country, in addition to national health programs are the main factors behind this achievement. The decrease of infant mortality has led to an increase in the number of vulnerable infants with disorders that evolve to chronic conditions and compromised quality of life. In Chile, 12.9 % of the population has some degree of disability and 9 % has intellectual and developmental disability (IDD). Since 1994 several policies and laws have been enacted to protect children and adults with disabilities. Also, in 2008 Chile ratified the “Convention on the Rights of Persons with Disabilities” of the United Nations. During the past 10–20 years, governmental health programs for health promotion and protection of children’s rights have been created. These programs are aimed at underprivileged groups, including children with IDD. In Chile there are health surveillance programs for preterm children (PT) and for children with Down syndrome (DS). The growing group of children with autism spectrum disorder (ASD) needs more attention; at the time of writing, there is no special health program for them. Currently a National Health Program for Children has been developed including new recommendations for the care of children with IDD. However there are still inequities in the access to quality health care attention and therapies especially in regions far from the capital city. Some rehabilitation services are available for children with IDD, they mostly consist of physical and occupational therapy, and there is a big need of early intervention services.

La vacuna polio oral en lactantes no interfiere con la detección de enterovirus en sangre

Introduccion: No existen estudios que indiquen si la vacuna polio oral (VPO) produce viremia detectable mediante metodos moleculares. Una eventual viremia podria afectar el rendimiento de la RPC tiempo real para detectar enterovirus (EV) no polio, examen de creciente uso clinico en lactantes pequenos con fiebre sin foco. Objetivo: Determinar viremia post VPO en lactantes sanos, por metodos moleculares. Metodos: 50 menores de 3 meses, al momento de recibir su primera VPO se distribuyeron en forma aleatoria en 5 grupos: control, muestra de sangre pre-vacunacion; grupo 1, muestra al 2° dia; grupo 2, al 4° dia; grupo 3, al 6° dia y grupo 4, al 8° dia post-vacunacion. Se realizo RPC convencional especifica para virus polio y RPC tiempo real para EV no polio en las muestras de sangre y en muestras de VPO. Resultados: No se identifico presencia de material genetico de virus polio en lactante alguno, mientras que en 9 (18%) se identifico presencia de EV no polio. La RPC tiempo real para EV no polio no amplifico material genetico a partir de las muestras de VPO. Discusion: Los resultados sugieren que no existe viremia post-VPO detectable por metodos moleculares. Considerando que la RPC tiempo real de EV no polio de uso clinico no permite identificar la presencia de virus polio, estos hallazgos indican que no existiran falsos positivos de este examen como resultado de una vacunacion VPO reciente. Adicionalmente se documento presencia de EV no polio en sangre de lactantes asintomaticos.