What is a Pulsar by Cihan News Agency (CNA). An international team of astronomers has used X-ray telescopes in space and ground-based telescopes, including two of CSIRO's, to identify a. that switches between emitting X-rays and emitting radio waves.
The Panasonic Toughbook CF-53 is a beefy laptop with a rugged design that goes from the street to the office and out to the field without breaking a sweat.
A textbook is  a book used for the study of a subject. People use a textbook to learn facts and methods about a certain subject. Textbooks sometimes have questions to test the knowledge and understanding of the learner. A workbook is a type of textbook that has only practice questions and exercises. Workbooks are designed not to teach but to provide practice and to highlight areas which need more learning.