Scar

Scars are areas of fibrous tissue (fibrosis) that replace normal skin after injury. A scar results from the biological process of wound repair in the skin and other tissues of the body. Thus, scarring is a natural part of the healing process. With the exception of very minor lesions, every wound (e.g., after accident, disease, or surgery) results in some degree of scarring. An exception to this are animals with complete regeneration, which regrow tissue without scar formation.

Scar tissue is composed of the same protein (collagen) as the tissue that it replaces, but the fiber composition of the protein is different; instead of a random basketweave formation of the collagen fibers found in normal tissue, in fibrosis the collagen cross-links and forms a pronounced alignment in a single direction. This collagen scar tissue alignment is usually of inferior functional quality to the normal collagen randomised alignment. For example, scars in the skin are less resistant to ultraviolet radiation, and sweat glands and hair follicles do not grow back within scar tissues. A myocardial infarction, commonly known as a heart attack, causes scar formation in the heart muscle, which leads to loss of muscular power and possibly heart failure. However, there are some tissues (e.g. bone) that can heal without any structural or functional deterioration.

Atom

An atom is the smallest constituent unit of ordinary matter that has the properties of a chemical element. Every solid, liquid, gas, and plasma is composed of neutral or ionized atoms. Atoms are very small; typical sizes are around 100 pm (a ten-billionth of a meter, in the short scale). However, atoms do not have well-defined boundaries, and there are different ways to define their size that give different but close values.

Atoms are small enough that classical physics gives noticeably incorrect results. Through the development of physics, atomic models have incorporated quantum principles to better explain and predict the behavior.

Every atom is composed of a nucleus and one or more electrons bound to the nucleus. The nucleus is made of one or more protons and typically a similar number of neutrons (none in hydrogen-1). Protons and neutrons are called nucleons. More than 99.94% of an atom's mass is in the nucleus. The protons have a positive electric charge, the electrons have a negative electric charge, and the neutrons have no electric charge. If the number of protons and electrons are equal, that atom is electrically neutral. If an atom has more or fewer electrons than protons, then it has an overall negative or positive charge, respectively, and it is called an ion.

Official

An official is someone who holds an office (function or mandate, regardless whether it carries an actual working space with it) in an organization or government and participates in the exercise of authority (either his own or that of his superior and/or employer, public or legally private).

A government official or functionary is an official who is involved in public administration or government, through either election, appointment, selection, or employment. A bureaucrat or civil servant is a member of the bureaucracy. An elected official is a person who is an official by virtue of an election. Officials may also be appointed ex officio (by virtue of another office, often in a specified capacity, such as presiding, advisory, secretary). Some official positions may be inherited. A person who currently holds an office is referred to as an incumbent.

The word official as a noun has been recorded since the Middle English period, first seen in 1314. It comes from the Old French official (12th century), from the Latin officialis ("attendant to a magistrate, public official"), the noun use of the original adjective officialis ("of or belonging to duty, service, or office") from officium ("office"). The meaning "person in charge of some public work or duty" was first recorded in 1555. The adjective is first attested in English in 1533, via the Old French oficial.

Scientific Committee on Antarctic Research

The Scientific Committee on Antarctic Research (SCAR) is an interdisciplinary body of the International Council for Science (ICSU).

History

It was established in February 1958 to continue the international coordination of Antarctic scientific activities that had begun during the International Geophysical Year of 1957-58. SCAR is charged with the initiating, developing and coordinating scientific research in the Antarctic region. The scientific business of SCAR is conducted by its Standing Scientific Groups. SCAR also provides scientific advice to the Antarctic Treaty Consultative Meetings and other organizations on issues of science and conservation affecting the management of Antarctica and the Southern Ocean. In that role, SCAR has made numerous recommendations on a variety of matters, very few of which have been incorporated into Antarctic Treaty instruments.

Activities

SCAR meets every two years to conduct its administrative business at the SCAR Delegates Meeting. An Executive Committee elected from the delegates is responsible for the day-to-day administration of SCAR though its Secretariat at the Scott Polar Research Institute in Cambridge, England. The Executive Committee comprises the President and four Vice-Presidents. The SCAR Secretariat is staffed by the Executive Director, Executive Officer and an administrative assistant.