Echo

In audio signal processing and acoustics, an echo (plural echoes) is a reflection of sound, arriving at the listener some time after the direct sound. Typical examples are the echo produced by the bottom of a well, by a building, or by the walls of an enclosed room and an empty room. A true echo is a single reflection of the sound source. The time delay is the extra distance divided by the speed of sound. The word echo derives from the Greek ἠχώ (ēchō), itself from ἦχος (ēchos), "sound".Echo in the folk story of Greek is a mountain nymph whose ability to speak was cursed, only able to repeat the last words anyone spoke to her. Animals that use echoes are cetaceans (dolphins and whales) and bats.

Acoustic phenomenon

If so many reflections arrive at a listener that they are unable to distinguish between them, the proper term is reverberation. An echo can be explained as a wave that has been reflected by a discontinuity in the propagation medium, and returns with sufficient magnitude and delay to be perceived. Echoes are reflected off walls or hard surfaces like mountains and privacy fences.

Book

A book is a set of written, printed, illustrated, or blank sheets, made of ink, paper, parchment, or other materials, fastened together to hinge at one side. A single sheet within a book is a leaf, and each side of a leaf is a page. A set of text-filled or illustrated pages produced in electronic format is known as an electronic book, or e-book.

Books may also refer to works of literature, or a main division of such a work. In library and information science, a book is called a monograph, to distinguish it from serial periodicals such as magazines, journals or newspapers. The body of all written works including books is literature. In novels and sometimes other types of books (for example, biographies), a book may be divided into several large sections, also called books (Book 1, Book 2, Book 3, and so on). An avid reader of books is a bibliophile or colloquially, bookworm.

A shop where books are bought and sold is a bookshop or bookstore. Books can also be borrowed from libraries. Google has estimated that as of 2010, approximately 130,000,000 unique titles had been published. In some wealthier nations, printed books are giving way to the usage of electronic or e-books, though sales of e-books declined in the first half of 2015.

Pam Muñoz Ryan

Pam Muñoz Ryan was born in Bakersfield in the San Joaquin Valley of California on Silas December 25, 1951. She began writing when she was encouraged by a professor during graduate school. "It took me a number of years to make that leap of faith," she states when commenting on becoming a full-time writer. That came in 1994 after she published her first picture book.

She is the author of the bestselling books Esperanza Rising and Becoming Naomi León. Her other novels include Riding Freedom about Charley Parkhurst, which has won numerous awards, and Paint the Wind. Muñoz Ryan has also written several children's books. She has also recently written Echo.

The inspiration for Esperanza Rising came from her grandmother. As an immigrant from Mexico, she faced family complications, the death of her father, and racism due to her Hispanic heritage. She also won many awards including the National Education Associations Author recipient of the civil and human rights award. She is also a twice recipient of the Willa Cather literacy award for writing. Becoming Naomi León came from a 1997 visit to the Mexican city of Oaxaca to an annual Christmastime event called the "Night of the Radishes".

Book review

A book review is a form of literary criticism in which a book is analyzed based on content, style, and merit. A book review can be a primary source opinion piece, summary review or scholarly review. Books can be reviewed for printed periodicals, magazines and newspapers, as school work, or for book web sites on the Internet. A book review's length may vary from a single paragraph to a substantial essays. Such a review may evaluate the book on the basis of personal taste. Reviewers may use the occasion of a book review for a display of learning or to promulgate their own ideas on the topic of a fiction or non-fiction work.

There are a number of journals devoted to book reviews, and reviews are indexed in databases such as Book Review Index and Kirkus Reviews; but many more book reviews can be found in newspaper databases as well as scholarly databases such as Arts and Humanities Citation Index, Social Sciences Citation Index and discipline-specific databases.

See also

Amazon Echo

Amazon Echo is a wireless speaker and voice command device from Amazon.com. The device consists of a 9.25-inch (23.5 cm) tall cylinder speaker with a seven-piece microphone array. The device responds to the name "Alexa"; this "wake word" can be changed by the user (to also "Amazon" or "Echo" at present.). The device is capable of voice interaction, music playback, making to-do lists, setting alarms, streaming podcasts, playing audiobooks, and providing weather, traffic and other real time information. It can also control several smart devices.

Amazon had been developing Echo inside its Lab126 offices in Silicon Valley and Cambridge, Mass. since at least 2010. The device, codenamed 'Doppler' or 'Project D', was part of Amazon’s first attempts to expand its device portfolio beyond the original Kindle Ereader.

The Echo (initially limited to Amazon Prime members or by invitation) became widely available on June 23, 2015. Additionally, the service behind it (Alexa Voice Service) is available to be added to other devices and other companies’ devices and services are encouraged to connect to it (using the Alexa Skills Kit).