SOS

SOS is the international Morse code distress signal (· · · – – – · · ·). This distress signal was first adopted by the German government in radio regulations effective April 1, 1905, and became the worldwide standard under the second International Radiotelegraphic Convention, which was signed on November 3, 1906, and became effective on July 1, 1908. SOS remained the maritime radio distress signal until 1999, when it was replaced by the Global Maritime Distress and Safety System. SOS is still recognized as a visual distress signal.

The SOS distress signal is a continuous sequence of three dits, three dahs, and three dits, all run together without letter spacing. In International Morse Code, three dits form the letter S, and three dahs make the letter O, so "SOS" became an easy way to remember the order of the dits and dahs. In modern terminology, SOS is a Morse "procedural signal" or "prosign", and the formal way to write it is with a bar above the letters: SOS.

In popular usage, SOS became associated with such phrases as "Save Our Ship" or "Save Our Souls" or "Send Out Succour". SOS is only one of several ways that the combination could have been written; VTB, for example, would produce exactly the same sound, but SOS was chosen to describe this combination. SOS is the only nine-element signal in Morse code, making it more easily recognizable, as no other symbol uses more than eight elements.

21st Special Operations Squadron

The 21st Special Operations Squadron is a unit within the 352d Special Operations Group (352 SOG), United States Air Force, United States European Command, and was based at Royal Air Force base RAF Mildenhall in Suffolk, eastern England.

Mission

The 21st Special Operations Squadron, which fell under the 352nd Special Operations Group, RAF Mildenhall, UK, was inactivated on 31 October 2007 with the inactivation ceremony taking place at RAF Mildenhall, UK on 9 October temporarily ending the Air Force Special Operations vertical lift mission in Europe.

The inactivation of the Dust Devils was the first step in preparation for the arrival of the CV-22 tilt-rotor aircraft.

The 21st Special Operations Squadron's mission consisted of day or night, all-weather, low-level penetration of denied territory to provide infiltration, exfiltration, resupply, or fire support for elite air, ground, and naval forces. The unique capabilities of the MH-53J permitted the squadron to operate from unprepared landing zones.

1st Special Operations Squadron

The 1st Special Operations Squadron (1 SOS) is part of the 353d Special Operations Group at Kadena Air Base, Japan. It operates MC-130 Combat Talon II aircraft providing special operations capability. Air crews are trained in night low-level flying, using night vision goggles.

Mission

To deliver troops and equipment into denied areas during adverse weather conditions at night by airdrop or landing.

History

The 1st conducted gunnery testing and training from 1939–1942. It flew administrative airlift from 1949–1952 and 1953–1954.

The 1st flew combat missions in Southeast Asia from 8 July 1963 – 7 November 1972 and 15 December 1972 – 28 January 1973. It also trained Vietnamese Air Force pilots in counter-insurgency operations from, July 1963 – November 1972. It acquired the Combat Talon mission from the redesignated 90th Tactical Fighter Squadron on 15 December 1972. Three MC-130 Combat Talons from the 1st SOS led the Night One mission of Operation Eagle Claw, the hostage rescue mission in Iran, in April 1980.

TRIX (operating system)

TRIX is a network-oriented research operating system developed in the late 1970s at MIT's Laboratory for Computer Science (LCS) by Professor Steve Ward and his research group. It ran on the NuMachine and had remote procedure call functionality built into its kernel, but was otherwise a Version 7 Unix workalike.

Design and implementation

On startup, the NuMachine would load the same program on each CPU in the system, passing each instance of the program the numeric ID of the CPU it was running on. TRIX relied on this design to have the first CPU set up global data structures and then set a flag to signal when initialization completed. After that, each instance of the kernel was able to access global data. The system also supported data private to each CPU. Access to the filesystem was provided by a program in user space.

The kernel supported unnamed threads running in domains. A domain was the equivalent of a Unix process without a stack pointer (each thread in a domain had a stack pointer). A thread could change domains, and the system scheduler would migrate threads between CPUs in order to keep all processors busy. Threads had access to a single kind of mutual exclusion primitive, and one of seven priorities. The scheduler was designed to avoid priority inversion. User space programs could create threads through a spawn system call.

Trix (cereal)

Trix is a brand of breakfast cereal made by Kelloggs in Minneapolis, Minnesota, for the North American market and by Cereal Partners (using the Nestlé brand) elsewhere in the world. The cereal consists of fruit-flavored, sweetened, ground-corn pieces. They were originally spherical cereal pieces, but in 1991, were changed to puffed fruit-shaped pieces. In 2007, they reverted to their original shape in the United States. However, they maintained the fruit-shaped pieces in Mexico.

Overview

Trix, when introduced in 1955 by General Mills, was composed of more than 46% sugar. The original cereal included eight colors: "Blackberry Black", "Cherry Red", "Grapefruity Pink," "Wildberry Purple", "Blueberry Blue", "Orangey Orange", "Lemony Yellow", and "Raspberry Red". Twelve fruit shapes and colors were added over the years: "Grapity Purple", (1984), "Lime Green", (1991), "Banana Yellow", (1995), "Wildberry Blue", (1998–2007), "Watermelon", (1999), "Strawberry Red", (2002), "Raspberry Blue", (2003), "Apple", (2005), "Pineapple Yellow", (2007), "Wildberry Red", (2011), "Kiwi", (2012), and "Cherry Blue", (2015). In the cereal pieces were given a brighter, more colorful look. General Mills' Yoplait division produces a Trix-branded yogurt marketed to children with sweetened fruit flavors such as "Watermelon Burst". Later, Trix Swirls were introduced, with flavors such Trix Swirls have since been discontinued; and the pieces in the original Trix were changed to their original 2007 flavor and shape lineup in 2014.

Trix (technical analysis)

Trix (or TRIX) is a technical analysis oscillator developed in the 1980s by Jack Hutson, editor of Technical Analysis of Stocks and Commodities magazine. It shows the slope (i.e. derivative) of a triple-smoothed exponential moving average. The name Trix is from "triple exponential."

Trix is calculated with a given N-day period as follows:

Like any moving average, the triple EMA is just a smoothing of price data and, therefore, is trend-following. A rising or falling line is an uptrend or downtrend and Trix shows the slope of that line, so it's positive for a steady uptrend, negative for a downtrend, and a crossing through zero is a trend-change, i.e. a peak or trough in the underlying average.