3 research outputs found
Born Too Early and Too Small: Higher Order Cognitive Function and Brain at Risk at Ages 8-16
Prematurity presents a risk for higher order cognitive functions. Some of these deficits
manifest later in development, when these functions are expected to mature. However,
the causes and consequences of prematurity are still unclear. We conducted a
longitudinal study to first identify clinical predictors of ultrasound brain abnormalities in
196 children born very preterm (VP; gestational age 32 weeks) and with very low birth
weight (VLBW; birth weight 1500 g). At ages 8–16, the subset of VP-VLBW children
without neurological findings (124) were invited for a neuropsychological assessment
and an MRI scan (41 accepted). Of these, 29 met a rigorous criterion for MRI quality
and an age, and gender-matched control group (n = 14) was included in this study.
The key findings in the VP-VLBW neonates were: (a) 37% of the VP-VLBW neonates
had ultrasound brain abnormalities; (b) gestational age and birth weight collectively with
hospital course (i.e., days in hospital, neonatal intensive care, mechanical ventilation and
with oxygen therapy, surgeries, and retinopathy of prematurity) predicted ultrasound
brain abnormalities. At ages 8–16, VP-VLBW children showed: a) lower intelligent
quotient (IQ) and executive function; b) decreased gray and white matter (WM) integrity;
(c) IQ correlated negatively with cortical thickness in higher order processing cortical
areas. In conclusion, our data indicate that facets of executive function and IQ are the
most affected in VP-VLBW children likely due to altered higher order cortical areas and
underlying W
EpidemiologĂa e historia natural de las epilepsias de la infancia en la provincia de Albacete
Tesis doctoral inĂ©dita. Universidad AutĂłnoma de Madrid, Facultad de Medicina, Departamento de PediatrĂa. Fecha de lectura: 14 de Julio de 199
Optical microvariability of bright type 2 quasars
We present results from a project focused on searching optical microvariabilty (also known as “intra-night” variability) in type 2 - obscured - quasars. Optical microvariability can be described as very small changes in the flux, typically in the order of hundredths of magnitude, which can be observed on timescales of hours. Such studies have been so far conducted for samples of blazars and type 1, unobscured, AGNs, where the optical microvariability was detected with success. We have focused on obscured targets which would pose a challenge to the AGN standard model. In the present work, however, we have observed a sample of three bright (g mag< 17) type 2 quasar, based on the catalog of type 2 quasars from SDSS of Reyes et al. (2008). The observations were carried out with the 1.5 meter telescope at San Pedro Martir observatory in Mexico. The sample was observed during an observation period of four days in Johnsons V filter, resulting in at least two continuous intervals of observations per target during the observational run. We have obtained differential light curves for our sources as well as for the comparison stars. They were analyzed using one-way analysis of variance statistical test (ANOVA), which has been repeatedly used in the past for studies of unobscured targets. Based on the results from the statistical analysis, we show that at least two out of three observed targets appear to be variable on time scales of hours. So far, this is the first study which confirmed existence of optical microvariability in type 2 quasars.This research has been supported by the Spanish Ministerio de EconomĂa y Competitividad (MINECO) under the grant AYA2011-29517-C03-01. J. A. de Diego is grateful for support from grants SAB2010-0011 awarded by the Spanish MIED, and PAPIIT IN110013 awarded by the UNAM. J. I. González-Serrano is grateful for the support from AYA2011-29517-C03-02. The authors also would like to thank our colleague Yair Krongold for useful suggestions on this paper