Slate is a fine-grained, homogeneous metamorphic rock derived from an original shale-type sedimentary rock composed of clay or volcanic ash through low-grade regional metamorphism. It is the finest grained foliated metamorphic rock. Foliation may not correspond to the original sedimentary layering, but instead is in planes perpendicular to the direction of metamorphic compression; the foliation in slate is called "slaty cleavage". It is caused by strong compression causing fine grained clay flakes to regrow in planes perpendicular to the compression; when expertly "cut" by striking parallel to the foliation, with a specialized tool in the quarry, many slates will display a property called fissility, forming smooth flat sheets of stone which have long been used for roofing, floor tiles, other purposes. Slate is grey in color when seen, en masse, covering roofs. However, slate occurs in a variety of colors from a single locality. Slate is not to schist; the word "slate" is used for certain types of object made from slate rock.

It may mean a writing slate. They were traditionally a small, smooth piece of the rock framed in wood, used with chalk as a notepad or notice board, for recording charges in pubs and inns; the phrases "clean slate" and "blank slate" come from this usage. Before the mid-19th century, the terms slate and schist were not distinguished. In the context of underground coal mining in the United States, the term slate was used to refer to shale well into the 20th century. For example, roof slate referred to shale above a coal seam, draw slate referred to shale that fell from the mine roof as the coal was removed. Slate is composed of the minerals quartz and muscovite or illite along with biotite, chlorite and pyrite and, less apatite, kaolinite, tourmaline, or zircon as well as feldspar; as in the purple slates of North Wales, ferrous reduction spheres form around iron nuclei, leaving a light green spotted texture. These spheres are sometimes deformed by a subsequent applied stress field to ovoids, which appear as ellipses when viewed on a cleavage plane of the specimen.

Slate can be made into roofing slates, a type of roof shingle, or more a type of roof tile, which are installed by a slater. Slate has two lines of breakability – cleavage and grain – which make it possible to split the stone into thin sheets; when broken, slate retains a natural appearance while remaining flat and easy to stack. A series of "slate booms" occurred in Europe from the 1870s until the First World War following improvements in railway and waterway transportation systems. Slate is suitable as a roofing material as it has an low water absorption index of less than 0.4%, making the material waterproof. In fact, this natural slate, which requires only minimal processing, has the lowest embodied energy of all roofing materials. Natural slate is used by building professionals as a result of its durability. Slate is durable and can last several hundred years with little or no maintenance, its low water absorption makes it resistant to frost damage and breakage due to freezing. Natural slate is fire resistant and energy efficient.

Slate roof tiles are fixed either with nails, or with hooks as is common with Spanish slate. In the UK, fixing is with double nails onto timber battens or nailed directly onto timber sarking boards. Nails were traditionally of copper, although there are modern alloy and stainless steel alternatives. Both these methods, if used properly, provide a long-lasting weathertight roof with a lifespan of around 80–100 years; some mainland European slate suppliers suggest that using hook fixing means that: Areas of weakness on the tile are fewer since no holes have to be drilled Roofing features such as valleys and domes are easier to create since narrow tiles can be used Hook fixing is suitable in regions subject to severe weather conditions, since there is greater resistance to wind uplift, as the lower edge of the slate is secured. The metal hooks are, however and may be unsuitable for historic properties. Slate tiles are used for interior and exterior flooring, stairs and wall cladding. Tiles are grouted along the edges.

Chemical sealants are used on tiles to improve durability and appearance, increase stain resistance, reduce efflorescence, increase or reduce surface smoothness. Tiles are sold gauged, meaning that the back surface is ground for ease of installation. Slate flooring can be slippery. Slate tiles were used in 19th century UK building construction and in slate quarrying areas such as Blaenau Ffestiniog and Bethesda, Wales there are still many buildings wholly constructed of slate. Slates can be set into walls to provide a rudimentary damp-proof membrane. Small offcuts are used as shims to level floor joists. In areas where slate is plentiful it is used in pieces of various sizes for building walls and hedges, sometimes combined with other kinds of stone. In modern homes slate is used as table coasters; because it is a good electrical insulator and fireproof, it was used to construct early-20th-century electric switchboards and relay controls for large electric motors. Fine slate can be used as a whetstone to hone knives.

Due to its thermal sta

Hasta la Vista (MC Solaar song)

"Hasta la vista" is a 2001 song recorded by the hip hop artist MC Solaar. It was the second single from his fifth studio album, Cinquième As. Released on May 2001, the song was the first number-one single for the singer in France; the song, composed by Alain J, Eric K-Roz, Claude M'Barali and Kurser, was recorded in Spanish language, included on the CD and the vinyl. The song contains many puns as well as numerous Latino components, such as the Spanish guitar played by the Italian-French performer Miro, the name of the song and the first verse in Spanish-language, the "atmosphere and the passionate singings of the refrain" performed by Moïra Conrath; the song started at number nine in France on 2 June 2001 jumped to number one and stayed there for five weeks. It totaled 13 weeks in the top ten, 22 weeks in the top 50 and 27 weeks in the top 100, it was certified Gold disc by the SNEP two months after its release and features at number 12 on 2001 annual chart. First number-one in France which mixes the French and Spanish languages, the song is to date MC Solaar's second most successful single in France.

As of July 2014, it was the 99th best-selling single of the 21st century in France, with 309,000 units sold. Charted for 17 weeks on the Ultratop 40, the song debuted at number 20 on 16 June 2001, reached the top ten two weeks and peaked at number five in its seventh week, it remained for nine weeks in the top ten kept on drop on the chart. It ranked number 31 on the year-end chart; the single achieved a moderate success in Switzerland: after a debut at number 23, its highest position, on 5 August, it dropped every week and fell off the chart after 14 weeks. CD maxi"Hasta la vista" — 0:15 "Hasta la vista" — 3:23 "¡Hasta la vista mi amor!" — 0:15 "¡Hasta la vista mi amor!" — 3:2312" maxi"Hasta la vista" — 0:15 "Hasta la vista" — 3:23 "¡Hasta la vista mi amor!" — 0:15 "¡Hasta la vista mi amor!" — 3:23 "C'est ça que les gens veulent" — 4:05 "Hasta la vista", music video

Susan J. Smith

Susan Jane Smith, is a British geographer and academic. Since 2009, she has been Mistress of Cambridge. Smith held the Ogilvie Chair of Geography at the University of Edinburgh from 1990–2004 and until 2009 was a professor of geography at Durham University, where she played a key role in establishing the Institute of Advanced Study. On 1 October 2011, she was conferred the title of Honorary Professor of Social and Economic Geography in the Department of Geography at the University of Cambridge for five years, which has since been renewed until 2021, she studied at Oxford University, reading Geography at St Anne's College and completing her DPhil at Nuffield College. She held Research Fellowships at St Peter's College, Oxford, at Brunel University and at the University of Glasgow. Smith's research is concerned with the challenge of inequality, addressing themes such as residential segregation, housing for health, fear of crime, her current work focuses on inequalities in the housing market. In 2010, Smith gave the Tanner Lectures on Human Values at Cambridge University with the title "Care-full markets – Miracle or Mirage?" which examined—from a perspective of the ethics of care—the moral economy of the housing market.

Her work combines qualitative and quantitative approaches, she is interested in an array of participatory techniques. In collaboration with Dr. Mia Gray and the Menagerie Theatre Company, Smith has developed a project on'public choices in times of austerity', an experiment in dramatizing the findings of a study in Interactive Forum Theatre style. Smith plays euphonium with the City of Cambridge Brass Band. In 1999, Smith was elected a Fellow of the Academy of Social Sciences. In 2000, she was elected Fellow of the Royal Society of Edinburgh. In 2008, she was elected Fellow of the British Academy. In 2010, she was appointed as a Tanner lecturer at Clare Hall, Cambridge, a recognition for'uncommon achievement and outstanding abilities in the field of human values'. In 2014, she was awarded the Victoria Medal of the Royal Geographical Society