Experimentos sorprendentes con la luz

Young readers will learn the ways that César Chávez fought to protect the rights and lives of migrant workers in this inspiring Spanish-translated biography that gives history behind protests and developments of unions that Chávez led. Vivid images and an interesting timeline of Chávez's life work in conjunction with supportive text and a helpful glossary, table of contents, and index to engage readers from cover to cover.

A land of extremes, from active volcanic peaks to dense rain forests, Guatemala has sustained great civilizations and attracted foreign conquerors. While shadows of its vicious, decades-long civil war still linger, Guatemala's people work toward peace and stability in the face of corruption and impunity. Illuminating photographs, insightful facts, and informative sidebars help the reader discover what it's like to live in today's Guatemala, its ancient beginnings, dramatic landscape, rich culture, resilient people, and more.

This Spanish language edition of Yuyi Morales's Pura Belpré Award winner and New York Times Bestseller Dreamers is now available in paperback! Caldecott Honor artist and six-time Pura Belpré winner Yuyi Morales's gorgeous book Dreamers, and its Spanish language version Soñadores, are about making a home in a new place. Yuyi and her son Kelly's passage was not easy, and Yuyi did not speak any English at the time. But together, they found an unexpected, unbelievable place: the public library. There, book by book, they untangled the language of this strange new land, and learned to make their ...

Esta cuarta edición expone los fundamentos de las señales y sistemas discretos en el tiempo y procesamiento digital de señales. Este texto es adecuado para estudiantes de Ingeniería eléctrica, ingeniería informática y Ciencia de la computación.