Geological and Natural History Survey of Canada

the survey of the virtual higher education in iran and the ways of its development and improvement

این پژوهش با هدف "بررسی وضعیت موجود آموزش عالی مجازی در ایران و راههای توسعه و ارتقای آن " و با روش توصیفی-تحلیلی و پیمایشی صورت پذیرفته است. بررسی اسنادو مدارک موجود در زمینه آموزش مجازی نشان داد تعداد دانشجویان و مقاطع تحصیلی و رشته محل های دوره های الکترونیکی چندان مطلوب نبوده و از نظر کیفی نیز وضعیت شاخص خدمات آموزشی اساتید و وضعیت شبکه اینترنت در محیط آموزش مجازی نامطلوب است.

United States Geological Survey

A geological history of reflecting optics.

Optical reflectors in animals are diverse and ancient. The first image-forming eye appeared around 543 million years ago. This introduced vision as a selection pressure in the evolution of animals, and consequently the evolution of adapted optical devices. The earliest known optical reflectors--diffraction gratings--are 515 Myr old. The subsequent fossil record preserves multilayer reflectors, ...

A geological history of the Turkana Basin.

The Turkana Basin preserves a long and detailed record of biotic evolution, cultural development, and rift valley geology in its sedimentary strata. Before the formation of the modern basin, Cretaceous fluvial systems, Paleogene lakes, and Oligo-Miocene volcano-sedimentary sequences left fossil-bearing strata in the region. These deposits were in part related to an early system of rift basins t...

Natural history of prostatic obstruction. A prospective survey.

THE aims of the investigation were set out in a letter by the secretary of the research committee of the Royal College of General Practitioners, East Anglia Faculty on 6 February 1961. These were to find out the answers to the following questions: 1. Which symptoms are indicative of prostatic obstruction and how long can surgery be reasonably delayed after the development of symptoms? 2. Whethe...