Libros de ciencias, página 12 de 2685

Supercritical fluids are neither gas nor liquid, but can be compressed gradually from low to high density and they are therefore interesting and important as tunable solvents and reaction media in the chemical process industry. By adjusting the density the properties of these fluids can be customised and manipulated for a given process - physical or chemical transformation. Separation and processing using supercritical solvents such as CO2 are currently on-line commercially in the food, essential oils and polymer industries. Many agencies and industries are considering the use of supercritical water for waste remediation. Supercritical fluid chromatography represents another, major analytical application. Significant advances have recently been made in materials processing, ranging from particle formation to the creation of porous materials.

The Maris Nostri Novus Atlas project was carried out by two archaeobotanists, Dr Diego Sabato and Dr Leonor Peña-Chocarro, researchers at the Archaeobiology Laboratory of the Institute of History which is part of the CSIC (Spanish National Research Counci

This text provides a supportive environment to help students successfully learn the content of a standard algebra and trigonometry course. By incorporating interactive learning techniques, the Aufmann team helps students to better understand concepts, focus their studying habits, and obtain greater mathematical success. Prerequisite review is include in the textbook (and supporting materials) so that instructors can spend less time covering review material and students can still fill in the gaps in their mathematical knowledge. Integrated Review Notes provided next to examples throughout the text help students see the key prerequisite skills used within the example. For added convenience, these example-specific notes direct students to the page(s) where they can practice and review the skills needed to understand the new concept, thus decreasing students'' frustration and increasing their success. Prepare for the Next Section Exercises, found at the end of the exercise sets, have been carefully selected to review the prerequisite skills students will need in the next section. Next to each exercise is a reference to a section of the text where students can go to review topics they don''t understand. Answers to all of these exercises are provided in the Answer Appendix to help students better understand what they need to do to prepare for the next section. Interactive reading and study support is provided through careful placement of a Question/Answer feature throughout the exposition of the text so that students can check their understanding of concepts, think more critically about the mathematics, and more actively engage in learning mathematics. To support students studying independently, the Answer to each question is conveniently provided as a footnote on the same page as the question. To create a link between the algebraic and visual representations of a solution, increase students'' understanding of the concept presented, and accommodate different learning styles, the authors have provided both an algebraic solution and a graphical solution (represented by either a coordinate grid graph or a graphing calculator screen) for appropriate examples. Focus on Problem Solving at the beginning of every chapter reviews and demonstrates various strategies used by successful problem-solvers. Students become more comfortable with problem-solving and have a collection of tips and strategies to refer t

En este breve pero intenso libro, la doctora Levi Montalcini desdeña las reflexiones consolatorias o las lamentaciones lúgubres sobre la vejez, para explicarnos que el cerebro puede seguir funcionando perfectamente incluso a una edad avanzada, a diferencia de lo que ocurre con otras funciones fisiologicas, ya que si bien es cierto que pierde algunas de sus capacidades, las sustituye con otras que compensan e incluso superan a las perdidas. La neurobiologia moderna demuestra que merced a la plasticidad neuronal el cerebro suple la perdida de celulas que acontece con la edad con la propiedad que tienen las restantes de compensar esa disminucion numerica con un aumento de las ramificaciones y la utilizacion de circuitos neuronales alternativos.