Isolated cultured roots of Convolvulus arvensis L. were incubated in 0.2 microcurie per milliliter methyl-(3)H-thymidine for 14 hours, for 64 hours, or for 14 hours followed by transfer to fresh nutrient medium without tritiated thymidine. Autoradiographs of serial, longitudinal sections of roots which were continuously incubated with tritiated thymidine showed that cells of the root cap colume...

This article examines the extent to which indicators of the college-going climate of urban high schools are associated with students’ application to, enrollment in, and choice among four-year colleges. The investigators examine two mechanisms by which high schools may shape college enrollment among low-income students in an urban school system: (1) by ensuring whether seniors who aspire to a fo...

The majority of pollinating insects are generalists whose lifetimes overlap flowering periods of many potentially suitable plant species. Such generality is instrumental in allowing exotic plant species to invade pollination networks. The particulars of how existing networks change in response to an invasive plant over the course of its phenology are not well characterized, but may shed light o...

ANTONIS MARKOGIANNAKIS, PANAYOTIS T. TASSIOS, MARIA LAMBIRI, LINDA R. WARD, JENNY KOUREA-KREMASTINOU, NICHOLAS J. LEGAKIS, THE GREEK NONTYPHOIDAL SALMONELLA STUDY GROUP,† AND ALKIVIADIS C. VATOPOULOS* Department of Microbiology and Department of Hygiene and Epidemiology, Medical School, University of Athens, and National Reference Centre for Salmonella and Shigella, National School of Public He...