Terahertz Superconducting Hot Electron Bolometer Heterodyne Array Receivers For Nasas Gusto Balloon Observatory

We demonstrate an ultra-compact Terahertz (THz) heterodyne detec- tion system based on a quantum cas- cade laser (QCL) as local oscillator and a hot electron bolometer (HEB) for the mixing. It relies on a new opti- cal coupling scheme where the local oscillator signal is coupled through the air side of the planar HEB an- tenna, while the signal to be de- tected is coupled to the HEB through the lens. This technique allows us to suppress the beam splitter usu- ally employed for heterodyne mea- surements. The mixer is a Niobium Nitride HEB with a log-spiral planar antenna on silicon and mounted on the back of a plano-convex silicon lens. We have developed a low power consumption and low beam di- vergence 3rd-order distributed feed- back laser with single mode emis- sion at the target frequency of 2.7 THz to be used as local oscillator for the heterodyne receiver. The cou- pling between the QC laser and the the HEB has been further optimized, using a dielectric hollow waveguide that reliably increases the laser beam directivity up to 55 dBi. Upon the high beam quality, sufficient output power in a single mode at the tar- geted frequency and low power dissi- pation of our local oscillator, we have build an ultra compact THz hetero- dyne receiver with sensitivity close to the state of the art at 2.7 THz.

Contents: Interplanetary gas and magnetic fields The terrestrial magnetic field The external terrestrial gravity field Corpuscular radiation in the vicinity of Earth Solar electromagnetic radiation The lunar environment Planetary environments Space environment of the solar system.

"Fletcherism: what it is: or, How I became young at sixty" by Horace fletcher is a fascinating book on nutrition and diet. The author here relates briefly the story of his regeneration, of how he rescued himself from the prospect of an early grave, and brought himself to his present splendid physical and mental condition. He tells of the discovery of his principles, which have helped millions of people to live better, happier, and healthier lives. The book is a good fit if you are concerned about health and diet.

Ptolemy's Almagest is one of the most influential scientific works in history. A masterpiece of technical exposition, it was the basic textbook of astronomy for more than a thousand years, and still is the main source for our knowledge of ancient astronomy. This translation, based on the standard Greek text of Heiberg, makes the work accessible to English readers in an intelligible and reliable form. It contains numerous corrections derived from medieval Arabic translations and extensive footnotes that take account of the great progress in understanding the work made in this century, due to the discovery of Babylonian records and other researches. It is designed to stand by itself as an interpretation of the original, but it will also be useful as an aid to reading the Greek text.

This volume presents the lectures of the nineteenth Canary Islands Winter School, dedicated to the Cosmic Microwave Background (CMB). This relict radiation from the very early Universe provides a fundamental tool for precision cosmology. Prestigious researchers in the field present a comprehensive overview of current knowledge of the CMB, reviewing the theoretical foundations, the main observational results and the most advanced statistical techniques used in this discipline. The lectures give coverage from the basic principles to the most recent research results, reviewing state of the art observational and statistical analysis techniques. The impact of new experiments and the constraints imposed on cosmological parameters are emphasized and put into the broader context of research in cosmology. This is an important resource for both graduate students and experienced researchers, revealing the spectacular progress that has been made in the study of the CMB within the last decade.

Absalom and Achitophel by John Dryden Absalom and Achitophel is "generally acknowledged as finest political satire in the English language."It is also described as an allegory regarding contemporary political events, and a mock heroic narrative. On the title page, Dryden himself describes it simply as "a poem." We are delighted to publish this classic book as part of our extensive Classic Library collection. Many of the books in our collection have been out of print for decades, and therefore have not been accessible to the general public. The aim of our publishing program is to facilitate rapid access to this vast reservoir of literature, and our view is that this is a significant literary work, which deserves to be brought back into print after many decades. The contents of the vast majority of titles in the Classic Library have been scanned from the original works. To ensure a high quality product, each title has been meticulously hand curated by our staff. Our philosophy has been guided by a desire to provide the reader with a book that is as close as possible to ownership of the original work. We hope that you will enjoy this wonderful classic work, and that for you it becomes an enriching experience.