David Castañeda

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Computers are an important part of modern education, yet many schoolchildren lack access to a computer at home. We test whether this impedes educational achievement by conducting the largest-ever field experiment that randomly provides free home computers to students. Although computer ownership and use increased substantially, we find no effects on any(More)
In-utero in-vivo injection and electroporation of the embryonic mouse neocortex provides a powerful tool for the manipulation of individual progenitors lining the walls of the lateral ventricle. This technique is now widely used to study the processes involved in corticogenesis by over-expressing or knocking down genes and observing the effects on cellular(More)
Boys are doing worse in school than are girls, which has been dubbed "the Boy Crisis." An analysis of the latest data on educational outcomes among boys and girls reveals extensive disparities in grades, reading and writing test scores, and other measurable educational outcomes, and these disparities exist across family resources and race. Focusing on(More)
The focus of this work has been the study of Cr(VI) removal from ground waters and the simultaneous concentration for its reuse using three different technological alternatives: anion-exchange resins, liquid-liquid extraction assisted by hollow fibre membranes and emulsion pertraction. The viability of the considered objectives, i.e., Cr(VI) separation(More)
Many surgeons are also pilots; the two activities demand similar skill sets. Surgeons have developed an interest in aviation models for managing risk and reducing adverse events, such as Crew Resource Management training. This article provides seven suggestions from aviators that might be adopted by surgeons in an effort to improve surgical care and(More)
The problem of detecting specific features of microscopic dynamics in the macroscopic behavior of a many-degrees-of-freedom system is investigated by analyzing the position and momentum time series of a heavy impurity embedded in a chain of nearest-neighbor anharmonic Fermi-Pasta-Ulam oscillators. Results obtained in a previous work [M. Romero-Bastida,(More)
The focus of this work has been the study of simultaneous removal and recovery of Cr(VI) from ground waters with a high concentration of the metal (700 mg/l). The main objectives of water cleaning were the decrease of the Cr(VI) concentration down to the limits indicated by the Spanish regulations for discharge into channel waters (0.5 mg/l) and the(More)
ICID (Integrated Circuit IDentification) is a small mixed-signal cell that can be added to the test logic on a CMOS integrated circuit. It provides a unique 224 bit identification number that can be accessed during die test. This identification can be used to correlate test information for individual die on the wafer, through package test, and into the(More)
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