The Impact of Ethnicity on Executive Functioning in Youth

Executive function can be defined as a group of processes that guide and direct cognitive functions (Isquith, Roth & Gioia, 2013). Relatively little is known about executive function in ethnic minority children. This dissertation examined whether ethnicity predicts performance and parent rating scores on three executive function processes. To date, no study has teased apart the effects of ethnic minority status and its confounding variables in executive function. A total of 134 Caucasian and African American youth between the ages of 11-17 were included in the study. Of those 134 youth, 116 had complete data (both performance-based scores and rating scales) and 18 had rating scales only and no performance-based scores. Results of the current study demonstrate that ethnicity does not predict performance scores or parent-report scores on any executive function after controlling for age, gender, comorbidity, diagnosis, and socioeconomic status. Comorbidity, or number of diagnoses was a significant predictor of performance scores and parent-report scores. Finally, socioeconomic status and age moderated the relationship between rating scales and performance-based measures, with youth over the age of 13 and youth of higher socioeconomic status reporting significantly fewer executive function deficits regardless of their scores on performance-based measures. Executive functions are an integral part of success across settings. There is a continued need to identify variables that impact executive functions in order to implement appropriate interventions

The Toxoplasma gondii plastid replication and repair enzyme complex, PREX

A plastid-like organelle, the apicoplast, is essential to the majority of medically and veterinary important apicomplexan protozoa including Toxoplasma gondii and Plasmodium. The apicoplast contains multiple copies of a 35 kb genome, the replication of which is dependent upon nuclear-encoded proteins that are imported into the organelle. In P. falciparum an unusual multi-functional gene, pfprex, was previously identified and inferred to encode a protein with DNA primase, DNA helicase and DNA polymerase activities. Herein, we report the presence of a prex orthologue in T. gondii. The protein is predicted to have a bi-partite apicoplast targeting sequence similar to that demonstrated on the PfPREX polypeptide, capable of delivering marker proteins to the apicoplast. Unlike the P. falciparum gene that is devoid of introns, the T. gondii prex gene carries 19 introns, which are spliced to produce a contiguous mRNA. Bacterial expression of the polymerase domain reveals the protein to be active. Consistent with the reported absence of a plastid in Cryptosporidium species, in silico analysis of their genomes failed to demonstrate an orthologue of prex. These studies indicate that prex is conserved across the plastid-bearing apicomplexans and may play an important role in the replication of the plastid genome

Existence Results for Abstract Partial Neutral Integro-differential Equation with Unbounded Delay

In this paper we study the existence and regularity of mild solutions for a class of abstract partial neutral integro-differential equations with unbounded delay.FONDECYT-CONICYT[1050314]FONDECYT-CONICYT[7050034]Capes, Brasi

Comportamiento frente al fuego de tableros y madera de Pino radiata con y sin pintura retardante de llama

En aplicaciones para la construcción se requiere aportar al conocimiento del comportamiento de la madera y tableros a base de madera frente a la acción del fuego para mejorar condiciones de uso en servicio. Se comparó en tableros a base de madera y en madera sólida de pino radiata el efecto de una pintura retardante de fuego y testigos sin pintar, con el propósito de discriminar entre tipos de tableros y comparar con respecto a la madera sólida.Los tableros ensayados fueron: Contrachapado estructurales de Pino radiata D. Don, Oriented Strand Board (OSB), Medium Density Fiberboard (MDF), Hard Board (HB) y tableros de partículas, los que fueron pintados superficialmente con pintura retardante de llama y comparados con tableros sin protección. Se incluyó en el estudio, madera de pino radiata con y sin retardante de llama.El análisis estadístico indicó diferencias significativas en pérdida de peso e índice de carbonización para todos los tableros con retardante de llama al compararlos con los tableros sin protección. Entre tableros estructurales: contrachapados y OSB, el contrachapado con retardante de llama fue el que presentó un mejor comportamiento frente al fuego y, HB presentó el comportamiento más deficiente.Se demostró que una pintura retardante de llama resulta efectiva en la protección de los tableros estudiados al comparar con tableros sin protección.La aplicación de esta norma de ensayo fue un buen indicador del comportamiento al fuego y aportó información significativa de los tableros, aconsejándose su empleo como un complemento de los ensayos de resistencia al fuego que se realizan a escala real. AbstractIn housing contruction to require increase the knowledge of these materials behavior against to deterioration agents. The security opposite to the fire action is fundamental to improve their use in service.The boards tested were: radiata pine structural Plywood, Oriented Strand Board (OSB), Medium Density Fiberboard (MDF), Hard Board (HB) and particleboard, which were protected with flame retardant paint and were compared with boards without protection.  Radiata pine wood with and without flame retardant paint was included in the study.The statistical analysis showed significant differences in weight loss and carbonization index for all the boards with flame retardant compared them with the boards without protection. Between structural boards: plywood and OSB, plywood with flame retardant was the one that presented best fire performance, while HB presented the worst behavior.It was demonstrated that the flame retardant paint of turns out to be effective in the protection of the boards studied on having compared with boards without protection.The implementation of this standard test was a good indicator of the fire performance and contributed with significant information of the boards, its utilization is advised as a complement to fire resistance test carried out at real scale

Emergent bursting and synchrony in computer simulations of neuronal cultures

Experimental studies of neuronal cultures have revealed a wide variety of spiking network activity ranging from sparse, asynchronous firing to distinct, network-wide synchronous bursting. However, the functional mechanisms driving these observed firing patterns are not well understood. In this work, we develop an in silico network of cortical neurons based on known features of similar in vitro networks. The activity from these simulations is found to closely mimic experimental data. Furthermore, the strength or degree of network bursting is found to depend on a few parameters: the density of the culture, the type of synaptic connections, and the ratio of excitatory to inhibitory connections. Network bursting gradually becomes more prominent as either the density, the fraction of long range connections, or the fraction of excitatory neurons is increased. Interestingly, biologically prevalent values of parameters result in networks that are at the transition between strong bursting and sparse firing. Using principal components analysis, we show that a large fraction of the variance in firing rates is captured by the first component for bursting networks. These results have implications for understanding how information is encoded at the population level as well as for why certain network parameters are ubiquitous in cortical tissue

Tratamiento químico de acetilación en madera de Pinus radiata

Al saturar la pared celular de la madera con anhídrido acético, se reemplazan los grupos hi-droxilos libres de las macromoléculas celulosa y hemicelulosa. Con ello se logra rellenar los espacios moleculares con grupos acetilo y así evitar que éstos reaccionen con las moléculas de agua o con los complejos enzimáticos de los hongos de pudrición. Así, se produce la muerte de los hongos por falta de alimento. Con esta modificación química de la madera también se ha mejorado la estabilidad dimensional y la resistencia a agentes xilófagos. Bajo esta premisa, se evaluó el tratamiento químico de acetilación para la protección de madera de Pinus radiata D. Don. Se empleó una metodología en condiciones de laboratorio  que permitió determinar el efecto de la acetilación sobre las propiedades de: contenido de humedad; densidad; absorción de agua; estabilidad dimensional y biodegradación por hongos en madera de Pinus radiata D. Don.Se trabajó con dos tiempos de inmersión en anhídrido acético y dos tiempos en autoclave logran-do ganancias en peso que fueron desde 6 a 20%. Se mejoraron algunas propiedades de la madera del Pinus radiata D. Don, tales como: a) la resistencia a la degradación producto de la acción de hongos de pudrición café, dado que las pérdidas de peso en las maderas acetiladas fueron desde 1.38% a 17.43% en comparación con la madera control que alcanzó un 64.94%, con el mismo hongo; b) Con un hongo de pudrición blanca se obtuvieron valores de pérdida de peso en madera acetilada que fueron entre 2.96% y 9.12% en comparación con madera no acetilada que exhibió sólo 17.9%, tras cuatro meses de exposición. Además, se mejoraron las propiedades de estabilidad dimensional y absorción de agua. AbstractWhen woody cell wall is saturated with acetic anhydride, the free hydroxyl groups present on ce-llulosic structures are replaced. Thus, the capillary spaces are filled with acetyl groups and this repla-cement avoids further reactions with water or enzymatic degradation provoked by rot fungi. So, the death of different fungi is produced by the lack of food. It has been observed too that this chemical modification has improved the dimensional stability and the resistance to xylophages agents. Under this premise, we conducted a research in order to test acetylation of Pinus radiata D. Don wood as a strategy for their protection. An experimental methodology was used under laboratory conditions to determine the effect of the acetylation on some properties such as: water content; density, water uptake; dimensional stability and biodegradation provoked by rot fungi in Pinus radiata D. Don. Two immersion times of pine wood on acetic anhydride and two times in autoclave were tested (30 and 60 minutes). Thus, observed weight gains ranged between 6 and 20%. We also noted the improvement of other properties such as: a) the resistance to the degradation provoked by brown rot fungi, because in treated wood the weight losses ranged between 1.38% and 17.43% in comparison to control samples which reached 64.94% when the same fungi strain was used; b) when a white rot fungi strain was tested, weight losses ranged between 2.96% and 9.12% for acetylated samples in comparison to untreated pieces which showed 17.9% aft er 4 months of incubation. Furthermore, the dimensional stability and water absorption capacity improved

The Toxoplasma gondii Plastid replication and Repair Enzyme Complex, PREX

A plastid-like organelle, the apicoplast, is essential to the majority of medically and veterinary important apicomplexan protozoa including Toxoplasma gondii and Plasmodium. The apicoplast contains multiple copies of a 35 kb genome, the replication of which is dependent upon nuclear-encoded proteins that are imported into the organelle. In P. falciparum an unusual multi-functional gene, pfprex, was previously identified and inferred to encode a protein with DNA primase, DNA helicase and DNA polymerase activities. Herein, we report the presence of a prex orthologue in T. gondii. The protein is predicted to have a bi-partite apicoplast targeting sequence similar to that demonstrated on the PfPREX polypeptide, capable of delivering marker proteins to the apicoplast. Unlike the P. falciparum gene that is devoid of introns, the T. gondii prex gene carries 19 introns, which are spliced to produce a contiguous mRNA. Bacterial expression of the polymerase domain reveals the protein to be active. Consistent with the reported absence of a plastid in Cryptosporidium species, in silico analysis of their genomes failed to demonstrate an orthologue of prex. These studies indicate that prex is conserved across the plastid-bearing apicomplexans and may play an important role in the replication of the plastid genom