English language learners and kindergarten entry age: Achievement and social-emotional effects     

Michael Gottfried  Vi-Nhuan Le  Ashlesha Datar 《The Journal of educational research》2016,109(4):424-435

In evaluating the role of kindergarten entry age, previous researchers have not examined the entry-age effects for English language learners (ELL). Additionally, little work has assessed the role of entry age on both achievement and social-emotional outcomes. This study is the first to do both simultaneously. The authors used data from a longitudinal study that followed a national sample of U.S. students from kindergarten through Grade 5. Relying on variation in children's birth dates and in states' kindergarten entrance age cutoffs, the authors estimated how differences in the age at which children enroll in kindergarten are related to their achievement and social-emotional outcomes. Our results show that enrolling in kindergarten as an older entrant is associated with significantly higher achievement and social-behavioral outcomes during the early elementary school years for ELL students, but that these effects largely disappear by the end of elementary school. Policy implications are addressed.  相似文献   

Differential electronic detector to monitor apoptosis using dielectrophoresis-induced translation of flowing cells (dielectrophoresis cytometry)     

Marija Nikolic-Jaric  Tim Cabel  Elham Salimi  Ashlesha Bhide  Katrin Braasch  Michael Butler  Greg E. Bridges  Douglas J. Thomson 《Biomicrofluidics》2013,7(2)

The instrument described here is an all-electronic dielectrophoresis (DEP) cytometer sensitive to changes in polarizability of single cells. The important novel feature of this work is the differential electrode array that allows independent detection and actuation of single cells within a short section ( ～ 300?μm) of the microfluidic channel. DEP actuation modifies the altitude of the cells flowing between two altitude detection sites in proportion to cell polarizability; changes in altitude smaller than 0.25 μm can be detected electronically. Analysis of individual experimental signatures allows us to make a simple connection between the Clausius-Mossotti factor (CMF) and the amount of vertical cell deflection during actuation. This results in an all-electronic, label-free differential detector that monitors changes in physiological properties of the living cells and can be fully automated and miniaturized in order to be used in various online and offline probes and point-of-care medical applications. High sensitivity of the DEP cytometer facilitates observations of delicate changes in cell polarization that occur at the onset of apoptosis. We illustrate the application of this concept on a population of Chinese hamster ovary (CHO) cells that were followed in their rapid transition from a healthy viable to an early apoptotic state. DEP cytometer viability estimates closely match an Annexin V assay (an early apoptosis marker) on the same population of cells.  相似文献