Homelessness is lacking stable and appropriate housing. People can be categorized as homeless if they are: living on the streets (primary homelessness); moving between temporary shelters, including houses of friends, family and emergency accommodation (secondary homelessness); living in private boarding houses without a private bathroom or security of tenure (tertiary homelessness). The legal definition of homeless varies from country to country, or among different jurisdictions in the same country or region. United States government homeless enumeration studies also include people who sleep in a public or private place not designed for use as a regular sleeping accommodation for human beings. People who are homeless are most often unable to acquire and maintain regular, safe, secure and adequate housing due to income that is inconsistent or lacking altogether. Homelessness and poverty are interrelated. There is no methodological consensus on counting the homeless and identifying their needs; therefore in most cities only estimated homeless populations are known.
In 2005, an estimated 100 million people worldwide were homeless and as many as one billion people (one in 6.5 at the time) live as squatters, refugees or in temporary shelter, all lacking adequate housing. Historically in the Western countries, the majority of homeless have been men (50–80%), with single males particularly over represented.
When compared to the general population, people who are homeless experience higher rates of adverse physical and mental health outcomes. Chronic disease severity, respiratory conditions, rates of mental health illnesses and substance use are all often greater in homeless populations than the general population. Homelessness is also associated with a high risk of suicide attempts. People experiencing homelessness have limited access to resources and are often disengaged from health services, making them that much more susceptible to extreme weather events (e.g., extreme cold or heat) and ozone levels. These disparities often result in increased morbidity and mortality in the homeless population.
There are a number of organizations that provide help for homeless people. Most countries provide a variety of services to assist homeless people. These services often provide food, shelter (beds), and clothing and may be organized and run by community organizations (often with the help of volunteers) or by government departments or agencies. These programs may be supported by the government, charities, churches, and individual donors. Many cities also have street newspapers, which are publications designed to provide employment opportunities to homeless people. While some homeless people have jobs, some must seek other methods to make a living. Begging or panhandling is one option, but is becoming increasingly illegal in many cities. People who are homeless may have additional conditions, such as physical or mental health issues or substance addiction; these issues make resolving homelessness a challenging policy issue.A computer is a machine that can be programmed to carry out sequences of arithmetic or logical operations automatically. Modern computers can perform generic sets of operations known as programs. These programs enable computers to perform a wide range of tasks. A computer system is a "complete" computer that includes the hardware, operating system (main software), and peripheral equipment needed and used for "full" operation. This term may also refer to a group of computers that are linked and function together, such as a computer network or computer cluster.
A broad range of industrial and consumer products use computers as control systems. Simple special-purpose devices like microwave ovens and remote controls are included, as are factory devices like industrial robots and computer-aided design, as well as general-purpose devices like personal computers and mobile devices like smartphones. Computers power the Internet, which links hundreds of millions of other computers and users.
Early computers were meant to be used only for calculations. Simple manual instruments like the abacus have aided people in doing calculations since ancient times. Early in the Industrial Revolution, some mechanical devices were built to automate long tedious tasks, such as guiding patterns for looms. More sophisticated electrical machines did specialized analog calculations in the early 20th century. The first digital electronic calculating machines were developed during World War II. The first semiconductor transistors in the late 1940s were followed by the silicon-based MOSFET (MOS transistor) and monolithic integrated circuit (IC) chip technologies in the late 1950s, leading to the microprocessor and the microcomputer revolution in the 1970s. The speed, power and versatility of computers have been increasing dramatically ever since then, with transistor counts increasing at a rapid pace (as predicted by Moore's law), leading to the Digital Revolution during the late 20th to early 21st centuries.
Conventionally, a modern computer consists of at least one processing element, typically a central processing unit (CPU) in the form of a microprocessor, along with some type of computer memory, typically semiconductor memory chips. The processing element carries out arithmetic and logical operations, and a sequencing and control unit can change the order of operations in response to stored information. Peripheral devices include input devices (keyboards, mice, joystick, etc.), output devices (monitor screens, printers, etc.), and input/output devices that perform both functions (e.g., the 2000s-era touchscreen). Peripheral devices allow information to be retrieved from an external source and they enable the result of operations to be saved and retrieved.Survival, or the act of surviving, is the propensity of something to continue existing, particularly when this is done despite conditions that might kill or destroy it. The concept can be applied to humans and other living things (or, hypothetically, any sentient being), to physical object, and to abstract things such as beliefs or ideas. Living things generally have a self-preservation instinct to survive, while objects intended for use in harsh conditions are designed for survivability. Survival tools can be anything from water filter bottles to tactical self-defence pens and even a smartphone can act as a survival tool.