Internet television - Wikipedia. Internet television (or online television) is the digital distribution of television content, such as TV shows, via the public Internet (which also carries other types of data), as opposed to dedicated terrestrial television via an over- the- air aerial system, cable television, and/or satellite television systems. It is sometimes called web television, though this phrase is also used to describe the genre of TV shows broadcast only online. Elements[edit]Internet television is a type of over- the- top content. Over- the- top" (OTT) is the delivery of audio, video, and other media over the Internet without the involvement of a multiple- system operator (such as a cable television provider) in the control or distribution of the content.

It has several elements: Content provider[edit]Examples include: An independent service, such as Netflix or Amazon Video, Hotstar, Google Play Movies, my. TV (Arabic), Sony LIV, Viewster, or Qello (which specializes in concerts). A service owned by a traditional cable, or satellite TV provider, such as Ditto. TV, Sling TV (owned by Dish Network) or Direc. TV (owned by AT& T)An international movies brand, such as Eros International or Eros Now.

A service owned by a traditional film or television network, television channel, or content conglomerate, such as BBC Three since 1. Jan 2. 01. 6, CBSN, CNNGo, HBO Now, Now TV (UK) (owned by Sky), Play. Station Vue (owned by Sony), or Hulu (a joint venture)A peer- to- peer video hosting service such as You.

Tube, Vimeo, or Crunchyroll. Combination services like TV UOL which combines a Brazilian Internet- only TV station with user- uploaded content, or Crackle, which combines content owned by Sony Pictures with user uploaded content. Audio- only services like Spotify, though not "Internet television" per se, are sometimes accessible through video- capable devices in the same way. For a more complete list, see List of Internet television providers and List of video hosting services. Internet[edit]The public Internet is used for transmission from the streaming servers to the consumer end- user. Receiver[edit]The receiver must have an Internet connection, typically by Wi- fi or Ethernet, and could be: A web browser running on a personal computer (typically controlled by mouse and keyboard) or mobile device, such as Firefox, Google Chrome, or Internet Explorer.

About the UltraViolet FAQ. This is a frequently asked questions (FAQ) document about UltraViolet, the online entertainment ecosystem. Watch Hide Online Idigitaltimes. It's not about wavelengths.

A mobile app running on a smartphone or tablet computer. A dedicated digital media player, typically with remote control. These can take the form of a small box, or even a stick that plugs directly into an HDMI port. Examples include Roku, Amazon Fire, Apple TV, Google TV, Boxee, and WD TV. Sometimes these boxes allow streaming of content from the local network or storage drive, typically providing an indirect connection between a television and computer or USB stick. A Smart. TV which has Internet capability and built- in software accessed with the remote control.

NWS Heat Safety Watches and Warnings Home page. The official SpectraLight website: maker of revolutionary ultraviolet [UV] disinfection systems for swimming pools & spas. Enjoy cleaner, safer, greener pools. Photosensitivity (sun allergy). Authoritative facts about the skin from DermNet New Zealand. Your UltraViolet Library is stored online in the cloud, so it goes everywhere you do. Stream online instantly or download for offline access anywhere – at the gym.

A Video Game Console connected to the internet such as the Xbox One and PS4. A DVD player or Blu- ray disc player with Internet capabilities in addition to its primary function of playing content from physical discs. A set- top box or digital video recorder (DVR) provided by the cable or satellite company or an independent party like Ti. Vo, which has Internet capabilities in addition to its primary function of receiving and recording programming from the non- Internet cable or satellite connection. Not all receiver devices can access all content providers. Most have websites that allow viewing of content in a web browser, but sometimes this is not done due to digital rights management concerns or restrictions.

While a web browser has access to any website, some consumers find it inconvenient to control and interact with content with a mouse and keyboard, inconvenient to connect a computer to their television, or confusing.[1] Manufacturers of Smart. TVs, boxes, sticks, and players must decide which providers to support, typically based either on popularity, common corporate ownership, or receiving payment from the provider. Display device[edit]A display device, which could be: Comparison with IPTV[edit]IPTV delivers television content using signals based on the Internet protocol (IP), through the open, unmanaged Internet with the "last- mile" telecom company acting only as the Internet service provider (ISP). As described above, "Internet television" is "over- the- top technology" (OTT). Both IPTV and OTT use the Internet protocol over a packet- switched network to transmit data, but IPTV operates in a closed system—a dedicated, managed network controlled by the local cable, satellite, telephone, or fiber- optic company.[2] In its simplest form, IPTV simply replaces traditional circuit switched analog or digital television channels with digital channels which happen to use packet- switched transmission.

In both the old and new systems, subscribers have set- top boxes or other customer- premises equipment that communicates directly over company- owned or dedicated leased lines with central- office servers. Packets never travel over the public Internet, so the television provider can guarantee enough local bandwidth for each customer's needs.

The Internet protocol is a cheap, standardized way to enable two- way communication and simultaneously provide different data (e. TV- show files, email, Web browsing) to different customers. This supports DVR- like features for time shifting television: for example, to catch up on a TV show that was broadcast hours or days ago, or to replay the current TV show from its beginning. It also supports video on demand—browsing a catalog of videos (such as movies or television shows) which might be unrelated to the company's scheduled broadcasts.

IPTV has an ongoing standardization process (for example, at the European Telecommunications Standards Institute). Comparison tables[edit]IPTVOver- the- top technology. Content provider. Local telecom. Studio, channel, or independent service. Transmission network.

Local telecom - dedicated owned or leased network. Public Internet + local telecom. Receiver. Local telecom provides (set- top box)Purchased by consumer (box, stick, TV, computer, or mobile)Display device. Screen provided by consumer. Screen provided by consumer. OTT (Over the Top Technology)IPTV (Internet Protocol Television)Examples.

Video on demand services like Play. Station Vue, Sky Go, You. Tube, Netflix, Amazon, Ditto. TV, Yupp. TV, Lovefilm, BBC i.

Photosensitivity Derm. Net New Zealand. Home ». Topics A–Z » Photosensitivity. Author: A/Prof Amanda Oakley, Dermatologist, Hamilton, New Zealand, 1. Updated by Prof Oakley, January 2. What is photosensitivity?

Photosensitivity refers to various symptoms, diseases and conditions caused or aggravated by exposure to sunlight. A rash due to photosensitivity is a photodermatosis (plural photodermatoses). If the rash is eczematous, it is a photodermatitis.

A chemical or drug that causes photosensitivity is a photosensitiser. A phototoxic reaction to a photosensitiser results in an exaggerated sunburn reaction and no immune reaction is involved. A photoallergic reaction to a photosensitiser results in photodermatitis and is due to delayed hypersensitivity reaction.

A photoexacerbated condition describes a flare of an underlying skin disease on exposure to sunlight. Who gets photosensitivity? Photosensitivity occurs in males and females of all races and at all ages.

Different types of photosensitivity may be prevalent at different times of life. Genetic and environmental factors are involved. People with very white skin who don’t tan on exposure to the sun (Fitzpatrick skin type 1), especially if they also have red hair and blue eyes, are often considered photosensitive, relative to people with darker skin phototypes that tan more easily. These fair skinned individuals do not have a photodermatosis. Classification of photosensitivity. Photosensitivity is classified into the following groups: Primary photodermatoses.

The causes of primary or idiopathic photodermatoses have not yet been discovered. Exposure to the sun produces a clearly defined disease entity. These include: With the exception of polymorphic light eruption and juvenile spring eruption, these disorders are rare. Exogenous photodermatoses. Exogenous photodermatoses are those in which phototoxic or photoallergic reaction is caused by an external photosensitiser.

These include: Photoexacerbated dermatoses. Photoexacerbated dermatoses include: Metabolic photodermatoses. Photosensitivity can be caused by a metabolic defect. The most common disorders of this type are porphyrias, in which phototoxic porphyrins accumulate in the skin. There are genetic defects in various enzymes, and the diseases may be activated by exposure to certain medications or toxins.

Clinical presentation depends on which enzyme is defective. Genetic photodermatoses.

Photosensitivity can be associated with a pre- existing genetic disorder. These are rare. What causes photosensitivity? Photosensitivity is caused by an abnormal reaction to some component of the electromagnetic spectrum of sunlight and a chromophore (reactive compound) within the skin.

The electromagnetic spectrum ranges from cosmic rays, invisible rays called ultraviolet radiation (UVR), through visible light, to infrared, microwaves and radiowaves. UVR has 3 portions. UVC: ultrashort wavelength rays 2.

UVB: short wavelength rays 2. UVA: longer wavelength rays 3. Patients can be sensitive to one kind of sunlight (i. UVB, UVA or visible light) or to a wider range of radiation.

The most common photosensitivity is to UVA. Properties of UVA include: Present throughout the year, but there is more UVA during summer. Present throughout the day, but there is more UVA around the solar noon that earlier or later.

UVA is of lower energy than UVB, thus photon for photon, UVA is less damaging than UVB to DNA in skin cells. UVA is however 1. UVBUVA can penetrate through the epidermis into the dermis thus UVA damages more deeply than UVBUVA can penetrate untreated and untinted glass, which blocks UVBUVA is blocked by polycarbonate and densely woven fabric. Porphyria is mainly triggered by exposure to visible light. What are the clinical features of photosensitivity? The clinical features depend on the specific photodermatosis. Photodermatoses affect areas exposed to sunlight (face, neck, hands) and do not affect areas not exposed to the light (covered at least by underwear), or are less severe in covered areas.

Sometimes they spare areas that are habitually exposed to the light, eg the face in polymorphic light eruption. Sometimes they only affect certain parts of the body, eg juvenile spring eruption is confined to the tops of the ears. Photodermatoses may also occur following indoor exposure to artificial sources of UVR (eg fluorescent lamps) or visible radiation. Rashes on exposed sites may be due to another cause. For example: Clues to photosensitivity include: Summer exacerbation; note that many photodermatoses are present year round.

Sharp cut- off between affected area and skin covered by clothing or jewellery (eg watch strap, ring)Sparing of folds of upper eyelids. Sparing of deep furrows on face and neck. Sparing of skin covered by hair. Sparing of skin shadowed by the ears, under the nose and under the chin. Sparing of the web spaces between the fingers.

Complications of photosensitivity. Severe photosensitivity can lead to a person being unable to go outdoors during the day unless completely covered (including face). This leads to social isolation and depression. Some photodermatoses cause permanent scarring. How is photosensitivity diagnosed?

Photosensitivity is diagnosed by the history of a skin problem arising on exposure to sunlight. The specific type is determined by examination of the skin and specific tests. Photosensitivity is sometimes confirmed by phototests — artificial light from various different sources and at different doses is shone on small areas of the skin to see whether the rash can be reproduced, or if sunburn occurs more easily than expected. These tests can be difficult to perform and to interpret, and are only available in specialised centres. Contact photosensitivity can be tested by photopatch tests, in association with standard patch tests. Adhesive patches containing known photosensitising materials are applied to the upper back, removed after two days, and light is shone on the area.

The reaction is observed two days later. Investigations may include: Full blood count.

Connective tissueantibodies including antinuclear antibodies (ANA), extractable nuclear antigens (ENA)Porphyrins in blood, urine and faeces. Patients suspected of porphyria cutanea tarda may also have liver function and iron tests. What is the treatment for photosensitivity? Management of photosensitivity involves sun protection and treatment of the underlying disorder. How can photosensitivity reactions be prevented?