The becquerel is the SI derived unit of radioactivity. One becquerel is defined as the activity of a quantity of radioactive material in which one nucleus decays per second; the becquerel is therefore equivalent to an inverse second, s−1. The becquerel is named after Henri Becquerel, who shared a Nobel Prize in Physics with Pierre and Marie Curie in 1903 for their work in discovering radioactivity; as with every International System of Units unit named for a person, the first letter of its symbol is uppercase. However, when an SI unit is spelled out in English, it should always begin with a lowercase letter —except in a situation where any word in that position would be capitalized, such as at the beginning of a sentence or in material using title case. 1 Bq = 1 s−1A special name was introduced for the reciprocal second to represent radioactivity to avoid dangerous mistakes with prefixes. For example, 1 µs−1 could be taken to mean 106 disintegrations per second: 1·−1 = 106 s−1. Other names considered were hertz, a special name in use for the reciprocal second, fourier.
The hertz is now only used for periodic phenomena. Whereas 1 Hz is 1 cycle per second, 1 Bq is 1 aperiodic radioactivity event per second; the gray and the becquerel were introduced in 1975. Between 1953 and 1975, absorbed dose was measured in rads. Decay activity was measured in curies before 1946 and in rutherfords between 1946 and 1975. Like any SI unit, Bq can be prefixed. For practical applications, 1 Bq is a small unit. For example, the 0.0169 g of potassium-40 present in a typical human body produces 4,400 disintegrations per second or 4.4 kBq of activity. The global inventory of carbon-14 is estimated to be 8.5×1018 Bq. The nuclear explosion in Hiroshima is estimated to have produced 8×1024 Bq; the becquerel succeeded the curie, an older, non-SI unit of radioactivity based on the activity of 1 gram of radium-226. The curie is defined as 3.7 · 1010 s 37 GBq. Conversion factors: 1 Ci = 3.7×1010 Bq = 37 GBq 1 μCi = 37,000 Bq = 37 kBq 1 Bq = 2.7×10−11 Ci = 2.7×10−5 μCi 1 MBq = 0.027 mCi For a given mass m of an isotope with atomic mass m a and a half-life of t 1 / 2, the radioactivity can be calculated using: A B q = m m a N A ln t 1 / 2 With N A = 6.02214179×1023 mol−1, the Avogadro constant.
Since m / m a is the number of moles, the amount of radioactivity A can be calculated by: A B q = n N A ln t 1 / 2 For instance, on average each gram of potassium contains 0.000117 gram of 40K that has a t 1 / 2 of 1.277×109 years = 4.030×1016 s, has an atomic mass of 39.964 g/mol, so the amount of radioactivity associated with a gram of potassium is 30 Bq. The following table shows radiation quantities in non-SI units. Background radiation Banana equivalent dose Counts per minute Ionizing radiation Orders of magnitude Radiation poisoning Relative Biological Effectiveness Rem Rutherford Sievert Derived units on the International Bureau of Weights and Measures web site
The Canadian Rockies or Canadian Rocky Mountains comprise the Canadian segment of the North American Rocky Mountains. They are the eastern part of the Canadian Cordillera, a system of multiple ranges of mountains which runs from the Canadian Prairies to the Pacific Coast; the Canadian Rockies mountain system comprises the southeastern part of this system, lying between the Interior Plains of Alberta and Northeastern British Columbia on the east to the Rocky Mountain Trench of BC on the west. The southern end borders Montana of the United States. In geographic terms the boundary is at the Canada/US border, but in geological terms it might be considered to be at Marias Pass in northern Montana; the northern end is at the Liard River in northern British Columbia. The Canadian Rockies have numerous high ranges, such as Mount Robson and Mount Columbia; the Canadian Rockies are composed of limestone. Much of the range is protected by national and provincial parks, several of which collectively comprise a World Heritage Site.
The Canadian Rockies are the easternmost part of the Canadian Cordillera, the collective name for the mountains of Western Canada. They form part of the American Cordillera, an continuous sequence of mountain ranges that runs all the way from Alaska to the tip of South America; the Cordillera, in turn, is the eastern part of the Pacific Ring of Fire that runs all the way around the Pacific Ocean. The Canadian Rockies are bounded on the east by the Canadian Prairies, on the west by the Rocky Mountain Trench, on the north by the Liard River. Contrary to popular misconception, the Rockies do not extend north into Yukon or Alaska, or west into central British Columbia. North of the Liard River, the Mackenzie Mountains, which are a distinct mountain range, form a portion of the border between the Yukon and the Northwest Territories; the mountain ranges to the west of the Rocky Mountain Trench in southern British Columbia are called the Columbia Mountains, are not considered to be part of the Rockies by Canadian geologists.
Mount Robson is the highest peak in the Canadian Rockies, but not the highest in British Columbia, since there are some higher mountains in the Coast Mountains and Saint Elias Mountains. Mount Robson lies on the continental divide near Yellowhead Pass, one of the lowest passes in the Canadian Rockies, is close to the Yellowhead Highway, its base is985 m above sea level, with a total vertical relief of 2,969 m. Mount Columbia is the second-highest peak in the Canadian Rockies, is the highest mountain in Alberta. Snow Dome is the hydrological apex of North America. Water flows off Snow Dome into three different watersheds, into the Pacific Ocean, Arctic Ocean, Atlantic Ocean via Hudson Bay; the Canadian Rockies are not the highest mountain ranges in Canada. Both the Saint Elias Mountains and the Coast Mountains have higher summits; the Canadian Rockies are subdivided into numerous mountain ranges, structured in two main groupings, the Continental Ranges, which has three main subdivisions, the Front Range, Park Ranges and Kootenay Ranges, the Northern Rockies which comprise two main groupings, the Hart Ranges and the Muskwa Ranges.
The division-point of the two main groupings is at Monkman Pass northwest of Mount Robson and to the southwest of Mount Ovington. The Canadian Rockies are noted for being the source of several major river systems, for the many rivers within the range itself; the Rockies form the divide between the Pacific Ocean drainage on the west and that of Hudson Bay and the Arctic Ocean on the east. Of the range's rivers, only the Peace River penetrates the range. Notable rivers originating in the Canadian Rockies include the Fraser, North Saskatchewan and Athabasca Rivers; the Canadian Rockies are quite different in appearance and geology from the American Rockies to the south of them. The Canadian Rockies are composed of layered sedimentary rock such as limestone and shale, whereas the American Rockies are made of metamorphic and igneous rock such as gneiss and granite; the Canadian Rockies are overall more jagged than the American Rockies because the Canadian Rockies have been more glaciated, resulting in pointed mountains separated by wide, U-shaped valleys gouged by glaciers, whereas the American Rockies are overall more rounded, with river-carved V-shaped valleys between them.
The Canadian Rockies are cooler and wetter, giving them moister soil, bigger rivers, more glaciers. The tree line is much lower in the Canadian Rockies than in the American Rockies. Five national parks are located within the Canadian Rockies, four of which are adjacent and make up the Canadian Rocky Mountain Parks; these four parks are Banff, Jasper and Yoho. The fifth national park, Waterton is not adjacent to the others. Waterton lies farther south, straddling the Canada–US border as the Canadian half of the Waterton-Glacier International Peace Park. All five of these parks, combined with three British Columbia provincial parks, were declared a single UNESCO World Heritage Site in 1984 for the unique mountain landscapes found there. Numerous provincial parks are located in the Canadian Rockies, including Hamber, Mount Assiniboine and Mount Robson parks. Throughout the Rockies, in the national parks, the Alpine Club of Canada maintains a series of alpine huts for use by mountaineers and adventurers.
The Canadian Pacific Railway was founded to provide a link from the province of British Columbia to the eastern provinces. The main difficulty in p
The Columbia River is the largest river in the Pacific Northwest region of North America. The river rises in the Rocky Mountains of Canada, it flows northwest and south into the US state of Washington turns west to form most of the border between Washington and the state of Oregon before emptying into the Pacific Ocean. The river is 1,243 miles long, its largest tributary is the Snake River, its drainage basin is the size of France and extends into seven US states and a Canadian province. The fourth-largest river in the United States by volume, the Columbia has the greatest flow of any North American river entering the Pacific; the Columbia and its tributaries have been central to the region's culture and economy for thousands of years. They have been used for transportation since ancient times, linking the region's many cultural groups; the river system hosts many species of anadromous fish, which migrate between freshwater habitats and the saline waters of the Pacific Ocean. These fish—especially the salmon species—provided the core subsistence for native peoples.
In the late 18th century, a private American ship became the first non-indigenous vessel to enter the river. In the following decades, fur trading companies used the Columbia as a key transportation route. Overland explorers entered the Willamette Valley through the scenic but treacherous Columbia River Gorge, pioneers began to settle the valley in increasing numbers. Steamships along the river linked facilitated trade. Since the late 19th century and private sectors have developed the river. To aid ship and barge navigation, locks have been built along the lower Columbia and its tributaries, dredging has opened and enlarged shipping channels. Since the early 20th century, dams have been built across the river for power generation, navigation and flood control; the 14 hydroelectric dams on the Columbia's main stem and many more on its tributaries produce more than 44 percent of total US hydroelectric generation. Production of nuclear power has taken place at two sites along the river. Plutonium for nuclear weapons was produced for decades at the Hanford Site, now the most contaminated nuclear site in the US.
These developments have altered river environments in the watershed through industrial pollution and barriers to fish migration. The Columbia begins its 1,243-mile journey in the southern Rocky Mountain Trench in British Columbia. Columbia Lake – 2,690 feet above sea level – and the adjoining Columbia Wetlands form the river's headwaters; the trench is a broad and long glacial valley between the Canadian Rockies and the Columbia Mountains in BC. For its first 200 miles, the Columbia flows northwest along the trench through Windermere Lake and the town of Invermere, a region known in British Columbia as the Columbia Valley northwest to Golden and into Kinbasket Lake. Rounding the northern end of the Selkirk Mountains, the river turns south through a region known as the Big Bend Country, passing through Revelstoke Lake and the Arrow Lakes. Revelstoke, the Big Bend, the Columbia Valley combined are referred to in BC parlance as the Columbia Country. Below the Arrow Lakes, the Columbia passes the cities of Castlegar, located at the Columbia's confluence with the Kootenay River, Trail, two major population centers of the West Kootenay region.
The Pend Oreille River joins the Columbia about 2 miles north of the US–Canada border. The Columbia enters eastern Washington flowing south and turning to the west at the Spokane River confluence, it marks the southern and eastern borders of the Colville Indian Reservation and the western border of the Spokane Indian Reservation. The river turns south after the Okanogan River confluence southeasterly near the confluence with the Wenatchee River in central Washington; this C‑shaped segment of the river is known as the "Big Bend". During the Missoula Floods 10,000 to 15,000 years ago, much of the floodwater took a more direct route south, forming the ancient river bed known as the Grand Coulee. After the floods, the river found its present course, the Grand Coulee was left dry; the construction of the Grand Coulee Dam in the mid-20th century impounded the river, forming Lake Roosevelt, from which water was pumped into the dry coulee, forming the reservoir of Banks Lake. The river flows past The Gorge Amphitheatre, a prominent concert venue in the Northwest through Priest Rapids Dam, through the Hanford Nuclear Reservation.
Within the reservation is Hanford Reach, the only US stretch of the river, free-flowing, unimpeded by dams and not a tidal estuary. The Snake River and Yakima River join the Columbia in the Tri‑Cities population center; the Columbia makes a sharp bend to the west at the Washington–Oregon border. The river defines that border for the final 309 miles of its journey; the Deschutes River joins the Columbia near The Dalles. Between The Dalles and Portland, the river cuts through the Cascade Range, forming the dramatic Columbia River Gorge. No other rivers except for the Klamath and Pit River breaches the Cascades—the other rivers that flow through the range originate in or near the mountains; the headwaters and upper course of the Pit River are on the Modoc Plateau. In contrast, the Columbia cuts through the range nearly a thousand miles from its source in the Rocky Mountains; the gorge is known
The mountain goat known as the Rocky Mountain goat, is a hoofed mammal endemic to North America. A subalpine to alpine species, it is a sure-footed climber seen on cliffs and ice. Despite its vernacular name, it is not a member of Capra, the genus that includes all other goats, such as the wild goat, Capra aegagrus, from which the domestic goat is derived; the mountain goat is an even-toed ungulate of the order Artiodactyla and the family Bovidae that includes antelopes and cattle. It belongs to the subfamily Caprinae, along with true goats, wild sheep, the chamois, the muskox and other species. Notably, the takins of the Himalayan region, while not a sister lineage of the mountain goat, are nonetheless closely related and coeval. Other members of this group are the true goats and the Himalayan tahr; the chamois and true sheep lineages are very related, while the muskox lineage is somewhat more distant. The mountain goats diverged from their relatives in the late Tortonian, some 7.5 to 8 million years ago.
Given that all major caprine lineages emerged in the Late Miocene and contain at least one but several species from the eastern Himalayan region, their most place of origin is between today's Tibet and Mongolia or nearby. The mountain goat's ancestors thus crossed the Bering Strait after they split from their relatives before the Wisconsinian glaciation. No Pliocene mountain goats have been identified yet. In the Pleistocene, the small prehistoric mountain goat Oreamnos harringtoni lived in the southern Rocky Mountains. Ancient DNA studies suggest that this was the sister species of the living mountain goat, not its ancestor; the mountain goat is the only living species in the genus Oreamnos. The name Oreamnos is derived from the Greek term oros "mountain" and the word amnos "lamb". Both billy and nanny mountain goats have beards, short tails, long black horns, 15–28 cm in length, which contain yearly growth rings, they are protected from the elements by their woolly white double coats. The fine, dense wool of their undercoats is covered by an outer layer of longer, hollow hairs.
Mountain goats molt in spring by rubbing against rocks and trees, with the adult billies shedding their extra wool first and the pregnant nannies shedding last. Their coats help them to withstand winter temperatures as low as −50 °F and winds of up to 160 kilometres per hour. A billy stands about 1 m at the shoulder to the waist and can weigh more than the nanny. Male goats have longer horns and longer beards than females. Mountain goats can weigh between 45 and 140 kg, billies will weigh less than 82 kg; the head-and-body length can range from 120–179 cm, with a small tail adding 10–20 cm. The mountain goat's feet are well-suited for climbing steep, rocky slopes with pitches exceeding 60°, with inner pads that provide traction and cloven hooves that can spread apart; the tips of their feet have sharp dewclaws. They have powerful neck muscles that help propel them up steep slopes; the mountain goat inhabits the Rocky Mountains and Cascade Range and other mountain regions of the Western Cordillera of North America, from Washington and Montana through British Columbia and Alberta, into the southern Yukon and southeastern Alaska.
Its northernmost range is said to be along the northern fringe of the Chugach Mountains in southcentral Alaska. Introduced populations can be found in such areas as Idaho, Utah, Oregon, South Dakota, the Olympic Peninsula of Washington. Mountain goats are the largest mammals found in their high-altitude habitats, which can exceed elevations of 13,000 feet, they sometimes descend to sea level in coastal areas although they are an alpine and subalpine species. The animals stay above the tree line throughout the year but they will migrate seasonally to higher or lower elevations within that range. Winter migrations to low-elevation mineral licks take them several kilometers through forested areas. Daily movements by individual mountain goats are confined to areas on the same mountain face, drainage basin, or alpine opening. Daily movements reflect an individual's needs for foraging, resting and security from predators or disturbance. Seasonal movements reflect nutritional needs, reproductive needs, climatic influences.
In general, seasonal movements are to exhibit a strong elevational component, whereby lower, forested elevations are used during the spring-summer to access lower elevation mineral licks, during winter to access forage. The farthest movements are expected to be by dispersing mountain goats; such movements are to involve mountain goats crossing forested valleys as they move between mountain blocks. Mountain goats spend most of their time grazing, their diets include grasses, sedges, mosses and twigs and leaves from the low-growing shrubs and conifers of the
The mule deer is a deer indigenous to western North America. The several subspecies include the black-tailed deer. Unlike the related white-tailed deer, found through most of North America east of the Rockies Mountains and in the valleys of the Rocky Mountains from Idaho and Wyoming northward, mule deer are only found on the western Great Plains, in the Rocky Mountains, in the United States southwest, on the West Coast of North America. Mule deer have been introduced to Argentina and Kauai, Hawaii; the most noticeable differences between white-tailed and mule deer are the size of their ears, the color of their tails, the configuration of their antlers. In many cases, body size is a key difference; the mule deer's tail is black-tipped. Mule deer antlers are bifurcated; each spring, a buck's antlers start to regrow immediately after the old antlers are shed. Shedding takes place in mid-February, with variations occurring by locale. Although capable of running, mule deer are seen stotting, with all four feet coming down together.
The mule deer is the larger of the two Odocoileus species on average, with a height of 80–106 cm at the shoulders and a nose-to-tail length ranging from 1.2 to 2.1 m. Of this, the tail may comprise 11.6 to 23 cm. Adult bucks weigh 55–150 kg, averaging around 92 kg, although trophy specimens may weigh up to 210 kg. Does are rather smaller and weigh from 43 to 90 kg, with an average of around 68 kg. Unlike the whitetail, the mule deer does not show marked size variation across its range, although environmental conditions can cause considerable weight fluctuations in any given population. An exception to this is the subspecies the Sitka deer; this race is markedly smaller than other mule deer, with an average weight of 54.5 kg and 36 kg in males and females, respectively. In addition to movements related to available shelter and food, the breeding cycle is important in understanding deer behavior; the "rut" or mating season begins in the fall as does go into estrus for a period of a few days and males become more aggressive, competing for mates.
Does may mate with more than one buck and go back into estrus within a month if they did not become pregnant. The gestation period is about 190–200 days, with fawns born in the spring; the survival rate of the fawns during labor is about 50%. Fawns are weaned in the fall after about 60 -- 75 days. Mule deer females give birth to two fawns, although if it is their first time having a fawn, they have just one. A buck's antlers fall off during the winter; the annual cycle of antler growth is regulated by changes in the length of the day. For a guide to identify the sex and age class of Rocky Mountain mule deer at various seasons see S1 File. For more information see the main article on deer; the size of mule deer groups follows a marked seasonal pattern. Groups are smallest during largest in early gestation. Besides humans, the three leading predators of mule deer are coyotes and cougars. Bobcats, Canadian lynxes, black bears, brown bears may prey upon adult deer, but most only attack fawns or infirm specimens or eat the deer after it has died naturally.
Bears and smaller-sized carnivores are opportunistic feeders, pose little threat to a strong, healthy mule deer. In 99 studies of mule deer diets, some 788 species of plants were eaten by mule deer, their diets vary depending on the season, geographic region and elevation; the studies gave these data for Rocky Mountain mule deer diets: The diets of mule deer are similar to those of whitetail deer in areas where they coexist. Mule deer are intermediate feeders rather than pure grazers. Mule deer adapt to agricultural products and landscape plantings. In the Sierra Nevada range, mule deer depend on the lichen Bryoria fremontii as a winter food source; the most common plant species consumed by mule deer are: Among trees and shrubs: Artemisia tridentata, Cercocarpus ledifolius, Cercocarpus montanus, Cowania mexicana, Populus tremuloides, Purshia tridentata, Quercus gambelii, Rhus trilobata. Among forbs: Achillea millefolium, Antennaria sp. Artemisia frigida, Artemisia ludoviciana, Aster spp. Astragalus sp.
Balsamorhiza sagittata, Cirsium sp. Erigeron spp. Geranium sp. Lactuca serriola, Lupinus spp. Medicago sativa, Penstemon spp. Phlox spp. Polygonum sp. Potentilla spp. Taraxacum officinale, Tragopogon dubius, Trifolium sp. and Vicia americana. Among grasses and grasslike species: Agropyron, Elytrigia, Pascopyrum sp. Pseudoroegneria spi
Canada is a country in the northern part of North America. Its ten provinces and three territories extend from the Atlantic to the Pacific and northward into the Arctic Ocean, covering 9.98 million square kilometres, making it the world's second-largest country by total area. Canada's southern border with the United States is the world's longest bi-national land border, its capital is Ottawa, its three largest metropolitan areas are Toronto and Vancouver. As a whole, Canada is sparsely populated, the majority of its land area being dominated by forest and tundra, its population is urbanized, with over 80 percent of its inhabitants concentrated in large and medium-sized cities, many near the southern border. Canada's climate varies across its vast area, ranging from arctic weather in the north, to hot summers in the southern regions, with four distinct seasons. Various indigenous peoples have inhabited what is now Canada for thousands of years prior to European colonization. Beginning in the 16th century and French expeditions explored, settled, along the Atlantic coast.
As a consequence of various armed conflicts, France ceded nearly all of its colonies in North America in 1763. In 1867, with the union of three British North American colonies through Confederation, Canada was formed as a federal dominion of four provinces; this began an accretion of provinces and territories and a process of increasing autonomy from the United Kingdom. This widening autonomy was highlighted by the Statute of Westminster of 1931 and culminated in the Canada Act of 1982, which severed the vestiges of legal dependence on the British parliament. Canada is a parliamentary democracy and a constitutional monarchy in the Westminster tradition, with Elizabeth II as its queen and a prime minister who serves as the chair of the federal cabinet and head of government; the country is a realm within the Commonwealth of Nations, a member of the Francophonie and bilingual at the federal level. It ranks among the highest in international measurements of government transparency, civil liberties, quality of life, economic freedom, education.
It is one of the world's most ethnically diverse and multicultural nations, the product of large-scale immigration from many other countries. Canada's long and complex relationship with the United States has had a significant impact on its economy and culture. A developed country, Canada has the sixteenth-highest nominal per capita income globally as well as the twelfth-highest ranking in the Human Development Index, its advanced economy is the tenth-largest in the world, relying chiefly upon its abundant natural resources and well-developed international trade networks. Canada is part of several major international and intergovernmental institutions or groupings including the United Nations, the North Atlantic Treaty Organization, the G7, the Group of Ten, the G20, the North American Free Trade Agreement and the Asia-Pacific Economic Cooperation forum. While a variety of theories have been postulated for the etymological origins of Canada, the name is now accepted as coming from the St. Lawrence Iroquoian word kanata, meaning "village" or "settlement".
In 1535, indigenous inhabitants of the present-day Quebec City region used the word to direct French explorer Jacques Cartier to the village of Stadacona. Cartier used the word Canada to refer not only to that particular village but to the entire area subject to Donnacona. From the 16th to the early 18th century "Canada" referred to the part of New France that lay along the Saint Lawrence River. In 1791, the area became two British colonies called Upper Canada and Lower Canada collectively named the Canadas. Upon Confederation in 1867, Canada was adopted as the legal name for the new country at the London Conference, the word Dominion was conferred as the country's title. By the 1950s, the term Dominion of Canada was no longer used by the United Kingdom, which considered Canada a "Realm of the Commonwealth"; the government of Louis St. Laurent ended the practice of using'Dominion' in the Statutes of Canada in 1951. In 1982, the passage of the Canada Act, bringing the Constitution of Canada under Canadian control, referred only to Canada, that year the name of the national holiday was changed from Dominion Day to Canada Day.
The term Dominion was used to distinguish the federal government from the provinces, though after the Second World War the term federal had replaced dominion. Indigenous peoples in present-day Canada include the First Nations, Métis, the last being a mixed-blood people who originated in the mid-17th century when First Nations and Inuit people married European settlers; the term "Aboriginal" as a collective noun is a specific term of art used in some legal documents, including the Constitution Act 1982. The first inhabitants of North America are hypothesized to have migrated from Siberia by way of the Bering land bridge and arrived at least 14,000 years ago; the Paleo-Indian archeological sites at Old Crow Flats and Bluefish Caves are two of the oldest sites of human habitation in Canada. The characteristics of Canadian indigenous societies included permanent settlements, complex societal hierarchies, trading networks; some of these cultures had collapsed by the time European explorers arrived in the late 15th and early 16th centuries and have only been discovered through archeological investigations.
The indigenous population at the time of the first European settlements is estimated to have been between 200,000