A plat consists of a map, drawn to scale, showing the divisions of a piece of land. U.S. General Land Office surveyors drew township plats to show the distance and bearing between survey corners, and sometimes included topographic or vegetation information. City, town or village plats show subdivisions into blocks with streets and alleys. Further refinement often splits blocks into individual lots, usually for the purpose of selling the described lots; this has become known as subdivision. After the filing of a plat, legal descriptions can refer to block and lot-numbers rather than portions of sections.
In order for plats to become legally valid, a local governing body, such as a public works department, urban planning commission, or zoning board must normally review and approve them.
A Plat of Subdivision appears when a landowner or municipality divides land into smaller parcels. If a landowner owns an acre of land, for instance, and wants to divide it into three pieces, a surveyor would have to take precise measurements of the land and submit the survey to the governing body, which would then have to approve it.
A Correction Plat or Amending Plat records minor corrections to an existing plat, such as correcting a surveying mistake or a scrivener's error. Such plats can sometimes serve to relocate lot-lines or other features, but laws usually tightly restrict such use.
A Vacating Plat functions to legally void a prior plat or portion of a plat. The rules normally allow such plats only when all the platted lots remain unsold and no construction of buildings or public improvements has taken place.
Other names associated with Parcel Maps are: Land Maps, Tax Maps, Real Estate Maps, Landowner Maps, Lot and Block Survey System and Land Survey Maps. Parcel maps, unlike any other public real estate record, have no federal, state or municipal oversight with their development.
Plats contain a number of informational elements:
The word "plat" in medieval English (and ever since) refers to a piece (or "plot") of land.
The creation of a plat map marks an important step in the process of incorporating a town or city according to United States law. Because the process of incorporation sometimes occurred at a courthouse, the incorporation papers for many American cities may be stored hundreds of miles away in another state.
For example, to view the original plat for the city of San Francisco, California, filed in 1849, one must visit the Clackamas County courthouse in Oregon City, Oregon, then the capital of the Oregon Territory and the site of the closest federal land office. This happened because California did not gain statehood until 1850.
Tissue plasminogen activator (abbreviated tPA or PLAT) is a protein involved in the breakdown of blood clots. Specifically, it is a serine protease found on endothelial cells, the cells that line the blood vessels. As an enzyme, it catalyzes the conversion of plasminogen to plasmin, the major enzyme responsible for clot breakdown. Because it works on the clotting system, tPA is used in clinical medicine to treat stroke.
The classic role of tPA is in the clotting system. Specifically, tPA catalyzes the conversion of plasminogen into plasmin. It does so by cleaving the single-chained plasminogen into two chains. These two chains are linked by a disulfide bond and the resulting molecule is called plasmin.
Increased enzymatic activity causes hyperfibrinolysis, which manifests as excessive bleeding. Decreased activity leads to hypofibrinolysis which can result in thrombosis or embolism.
Tissue plasminogen activator also plays a role in cell migration and tissue remodeling.
Tissue plasminogen activator is a protein encoded by the PLAT gene, which is located on chromosome 8. The primary transcript produced by this gene undergoes alternative splicing, producing three distinct messenger RNAs.
Recently tPA has been used to dissolve thrombi associated with ischemic strokes and brain injury.
In addition, people with frostbite that were treated with tPA had fewer amputations than those that were not.