Ozone depletion substances (ODS). These compounds are transported into the stratosphere by the winds after being emitted from the surface. Once in the stratosphere, they release halogen atoms through photodissociation, which catalyze the breakdown of ozone (O) into oxygen (O). Both types of ozone depletion were observed to increase as emissions of halocarbons increased. Ozone depletion and the ozone hole have generated worldwide concern over increased cancer risks and other negative effects. The ozone layer prevents most harmful UVB wavelengths of ultraviolet light (UV light) from passing through the Earth's atmosphere. These wavelengths cause skin cancer, sunburn and cataracts, which were projected
Session layer the person displayed on screen is the current speaker. Another application is in live TV programs, where streams of audio and video need to be seamlessly merged and transitioned from one to the other to avoid silent airtime or excessive overlap. The TCP/IP reference model does not concern itself with the OSI model's details of application or transport protocol semantics and therefore does not consider a session layer. OSI's session management in connection with the typical transport protocols (TCP, SCTP), is contained in the transport-layer protocols, or otherwise considered the realm of the application layer protocols. TCP/IP's layers are "descriptions"