6 resultados para model selection in binary regression
em Universidad del Rosario, Colombia
Resumo:
A completely effective vaccine for malaria (one of the major infectious diseases worldwide) is not yet available; different membrane proteins involved in parasite-host interactions have been proposed as candidates for designing it. It has been found that proteins encoded by the merozoite surface protein (msp)-7 multigene family are antibody targets in natural infection; the nucleotide diversity of three Pvmsp-7 genes was thus analyzed in a Colombian parasite population. By contrast with P. falciparum msp-7 loci and ancestral P. vivax msp-7 genes, specie-specific duplicates of the latter specie display high genetic variability, generated by single nucleotide polymorphisms, repeat regions, and recombination. At least three major allele types are present in Pvmsp-7C, Pvmsp-7H and Pvmsp-7I and positive selection seems to be operating on the central region of these msp-7 genes. Although this region has high genetic polymorphism, the C-terminus (Pfam domain ID: PF12948) is conserved and could be an important candidate when designing a subunit-based antimalarial vaccine.
Resumo:
A completely effective vaccine for malaria (one of the major infectious diseases worldwide) is not yet available; different membrane proteins involved in parasite-host interactions have been proposed as candidates for designing it. It has been found that proteins encoded by the merozoite surface protein (msp)-7 multigene family are antibody targets in natural infection; the nucleotide diversity of three Pvmsp-7 genes was thus analyzed in a Colombian parasite population. By contrast with P. falciparum msp-7 loci and ancestral P. vivax msp-7 genes, specie-specific duplicates of the latter specie display high genetic variability, generated by single nucleotide polymorphisms, repeat regions, and recombination. At least three major allele types are present in Pvmsp-7C, Pvmsp-7H and Pvmsp-7I and positive selection seems to be operating on the central region of these msp-7 genes. Although this region has high genetic polymorphism, the C-terminus (Pfam domain ID: PF12948) is conserved and could be an important candidate when designing a subunit-based antimalarial vaccine.
Resumo:
Objective: To establish a prediction model of the degree of disability in adults with Spinal CordInjury (SCI ) based on the use of the WHO-DAS II . Methods: The disability degree was correlatedwith three variable groups: clinical, sociodemographic and those related with rehabilitation services.A model of multiple linear regression was built to predict disability. 45 people with sci exhibitingdiverse etiology, neurological level and completeness participated. Patients were older than 18 andthey had more than a six-month post-injury. The WHO-DAS II and the ASIA impairment scale(AIS ) were used. Results: Variables that evidenced a significant relationship with disability were thefollowing: occupational situation, type of affiliation to the public health care system, injury evolutiontime, neurological level, partial preservation zone, ais motor and sensory scores and number ofclinical complications during the last year. Complications significantly associated to disability werejoint pain, urinary infections, intestinal problems and autonomic disreflexia. None of the variablesrelated to rehabilitation services showed significant association with disability. The disability degreeexhibited significant differences in favor of the groups that received the following services: assistivedevices supply and vocational, job or educational counseling. Conclusions: The best predictiondisability model in adults with sci with more than six months post-injury was built with variablesof injury evolution time, AIS sensory score and injury-related unemployment.
Resumo:
I test the presence of hidden information and action in the automobile insurance market using a data set from several Colombian insurers. To identify the presence of hidden information I find a common knowledge variable providing information on policyholder s risk type which is related to both experienced risk and insurance demand and that was excluded from the pricing mechanism. Such unused variable is the record of policyholder s traffic offenses. I find evidence of adverse selection in six of the nine insurance companies for which the test is performed. From the point of view of hidden action I develop a dynamic model of effort in accident prevention given an insurance contract with bonus experience rating scheme and I show that individual accident probability decreases with previous accidents. This result brings a testable implication for the empirical identification of hidden action and based on that result I estimate an econometric model of the time spans between the purchase of the insurance and the first claim, between the first claim and the second one, and so on. I find strong evidence on the existence of unobserved heterogeneity that deceives the testable implication. Once the unobserved heterogeneity is controlled, I find conclusive statistical grounds supporting the presence of moral hazard in the Colombian insurance market.
Resumo:
El artículo busca encontrar evidencia empírica de los determinantes de la salud, como una medición de capital salud en un país en desarrollo después de una profunda reforma en el sector salud. Siguiendo el modelo de Grossman (1972) y tomando factores institucionales, además de las variables individuales y socioeconómicas. Se usaron las encuestas de 1997 y 2000 donde se responde subjetivamente sobre el estado de salud y tipo de afiliación al sistema de salud. El proceso de estimación usado es un probit ordenado. Los resultados muestran una importante conexión entre las variables individuales, institucionales y socioeconómicas con el estado de salud. El efecto de tipo de acceso al sistema de salud presiona las inequidades en salud.
Resumo:
La actividad física regular desempeña un papel fundamental en la prevención y control de los desórdenes musculo esqueléticos, dentro de la actividad laboral del profesor de educación física. Objetivo: El propósito del estudio fue determinar la relación entre los niveles de actividad física y la prevalencia de los desórdenes musculo esqueléticos, en profesores de educación física de 42 instituciones educativas oficiales de Bogotá-Colombia. Métodos. Se trata de un estudio de corte transversal en 262 profesores de educación física, de 42 instituciones educativas oficiales de Bogotá - Colombia. Se aplicó de manera auto-diligenciada el Cuestionario Nórdico de desórdenes músculos esqueléticos y el Cuestionario IPAQ versión corta para identificar los niveles de actividad física. Se obtuvieron medidas de tendencia central y de dispersión para variables cuantitativas y frecuencias relativas para variables cualitativas. Se calculó la prevalencia de vida y el porcentaje de reubicación laboral en los docentes que habían padecido diferentes tipo de dolor. Para estimar la relación entre el dolor y las variables sociodemográficas de los docentes, se utilizó un modelo de regresión logística binaria simple. Los análisis fueron realizados en SPSS versión 20 y se consideró como significativo un valor p < 0.05 para el contraste de hipótesis y un nivel de confianza para la estimación de parámetros. Resultados: El porcentaje de respuesta fue del 83.9%, se consideraron válidos 262 registros, 22.5% eran de género femenino, la mayor cantidad de docentes de educación física se encuentraon entre 25 y 35 años (43,9%), frente a los desórdenes musculo esqueléticos, el 16.9% de los profesores reporto haberlos sufrido alguna vez molestias en el cuello, el 17,2% en el hombro, 27,9% espalda, 7.93% brazo y en mano el 8.4%. Los profesores con mayores niveles de actividad física, reportaron una prevalencia menor de alteraciones musculo esqueléticas de 16,9 % para cuello; 27.7% para dorsal/lumbar frente a los sujetos con niveles bajos de actividad física. La presencia de los desórdenes se asoció a los años de experiencia (OR 3.39 IC95% 1.41-7.65), a pertenecer al género femenino (OR 4.94 IC95% 1.94-12.59), a la edad (OR 5.06 IC95% 1.25-20.59), y al atender más de 400 estudiantes a cargo dentro de la jornada laboral (OR 4.50 IC95% 1.74-11.62). Conclusiones: En los profesores de Educación Física no sé encontró una relación estadísticamente significativa entre los niveles de actividad física y los desórdenes musculo esqueléticos medidos por auto reporte.