Dog sled
A dog sled is a sled that is pulled by sled dogs and can go over ice and snow. Dog sleds were first made by First Nations people in Canada before the English and French got there, because they had no horses so they used dogs to travel. They were also made by people in Norway, Sweden, Finland and Russia because it was also easier to travel with dogs in parts of those countries.
Racing dog sleds is a popular sport which a lot of people enjoy watching or actually going in the sleds to race. It is more popular in places where there is not much horse racing.
Multiset
A multiset (sometimes called a bag) is a concept from mathematics. In many ways, multisets are like sets. Certain items are either elements of that multiset, or they are not. However, multisets are different from sets: The same type of item can be in the multiset more than once. For this reason, mathematicians have defined a relation (function) that tells, how many copies of a certain type of item there are in a certain multiset. They call this "multiplicity". For example, in the multiset { "a", "a", "b", "b", "b", "c" }, the multiplicities of the members "a", "b", and "c" are 2, 3, and 1, respectively. From a set of "n" elements, the number of "r"-element multisets is written as formula_1. This is sometimes called the multiset coefficient.
A multiset is illustrated by means of a histogram.
A multiset can also be considered an unordered tuple:
One of the simplest examples is the multiset of prime factors of a number "n". Here, the underlying set of elements is the set of prime divisors of "n". For example, the number "120" has the prime factorisation
which gives the multiset {2, 2, 2, 3, 5}.
Another is the multiset of solutions of an algebraic equation. A quadratic equation, for example, has two solutions. However, in some cases they are both the same number. Thus the multiset of solutions of the equation could be { 3, 5 }, or it could be { 4, 4 }. In the latter case, it has a solution of multiplicity 2.
Tom Brokaw
Thomas John Brokaw (born February 6, 1940 in Webster, South Dakota) is a popular American television journalist and is the former anchorman (host) of "NBC Nightly News with Tom Brokaw". His last appearance as anchorman was on December 1, 2004. In the later part of hosting "NBC Nightly News", the program became the most-watched news program in the United States. Brokaw has received many awards and honors.
Brokaw was diagnosed with multiple myeloma in August 2013.
On April 26, 2018, Brokaw was accused of sexual harassment by two women.
Tuple
In mathematics, a tuple is a finite sequence of objects. Sometimes, the finite sequence is also called an "ordered list". This means that the order of the objects matter. In a tuple, the objects are either enclosed within parentheses (such as formula_1), or within angle brackets (such as formula_2). Each of the objects in the list has a certain type. A tuple consisting of "n" entries is called an n-tuple. Tuples are used to describe mathematical objects that are made of certain, well-defined components. They are also used very frequently with databases.
Tuples are different from sets:
In other words, tuples are like ordered multisets.
Manure
Manure is organic matter used as fertilizer in agriculture. Manures improve the fertility of the soil by adding organic matter and lots of nutrients, such as nitrogen that is trapped by bacteria in the soil. Higher organisms then feed on the fungi and bacteria in a chain of life.
The term "manure" was used for inorganic fertilizers in the past, but this usage is now very rare. Manure from birds and bats is called guano.
The word manure came from Middle English "manuren" meaning "to cultivate land," and initially from French "main-oeuvre" = "hand work" alluding to the work which involved manuring land.
There are two classes of manures in soil management: green manures and animal manures. Compost is distinguished from manure in that it is the "decomposed" remnants of organic materials (which may, nevertheless, include manure).
Most animal manure is feces–excrement of plant-eating mammals (herbivores) and plant material (often straw) which has been used as bedding for animals and thus is heavily contaminated with their feces and urine.
Green manures are crops grown for the express purpose of plowing them under. In so doing, fertility is increased through the nutrients and organic matter that are returned to the soil.
Manure has been used for centuries as a fertilizer for farming, as it is rich in nitrogen and other nutrients which facilitate the growth of plants. Liquid manure from pig/hog operations is usually knifed (injected) directly into soil to reduce the unpleasant odors. Manure from hogs and cattle is spread on fields using a manure spreader. Due to the relatively lower level of proteins in grasses, which herbivores eat, cattle manure has a milder smell than the dung of carnivores–for example, elephant dung is practically odorless. However, due to the quantity of manure applied to fields, odor can be a problem in some agricultural regions. Poultry droppings are harmful to plants when fresh but after a period of composting are valuable fertilizers.
The dried manure of animals has been used as fuel throughout history. Dried manure (usually known as dung) of cows was, and still is, an important fuel source in countries such as India, while camel dung may be used in treeless regions such as deserts. On the Oregon Trail, pioneering families collected large quantities of "buffalo chips" in lieu of scarce firewood. It has been used for many purposes, in cooking fires and to combat the cold desert nights.
Another use of manure is to make paper. This has been done with dung from elephants where it is a small industry in Africa and Asia, and also horses, llamas, and kangaroos. Other than the llama, these animals are not ruminants and thus tend to pass plant fibres undigested in their dung.
Nutrient
A nutrient is either a chemical element or compound used in an organism's metabolism or physiology. A nutrient is essential to an organism if it cannot be produced by the organism and must be obtained from a food source.
This article deals with nutrition in animals, especially humans. Nutrition in plants, fungi, bacteria and archaea is not discussed here.
The following table gives an idea of what elements are essential for humans:
Periodic table highlighting dietary elements
Histogram
A histogram is a concept from statistics. It is a graphical display that tells us about the distribution of the samples involved. They are commonly a picture made from a table with many categories. The table tells how many samples there are in each category.
The word "histogram" is derived from "histos" and "gramma" in Greek. "Histos" means "web" or "mast". "Gramma" means "drawing", "record" or "writing". A histogram of something is therefore, etymologically speaking, a drawing of the web of this something.
The histogram is one of the seven basic tools of quality control, which also include the Pareto chart, check sheet, control chart, cause-and-effect diagram, flowchart, and scatter diagram.
A population pyramid is two histograms.
A generalization of the histogram is kernel smoothing techniques. This will construct a smooth probability density function from the supplied data.
Green manure
Typically, a green manure crop is grown for a specific period, and then plowed under and incorporated into the soil. Green manures usually perform several functions, that include soil improvement and soil protection:
Historically, the practice of green manuring can be traced back to the fallow cycle of crop rotation, which was used to allow soils to recover.
Organic farming relies on soil health and cycling of nutrients through the soil using natural processes, such as the addition of animal manures. If animal manures are not available, in a stockless rotation, green manures perform a vital function of fertilization.
Normal distribution