Morenz died from problems with a broken leg, an injury he suffered in a game. After his death, the Canadiens stopped using his jersey number, the first time the team had done so for any player. When the Hockey Hall of Fame opened in 1945, Morenz was one of the first 12 people to be added. In 1950, the Canadian Press named him the best ice hockey player of the first half of the 20th century.
Norbury
Norbury is a town in the London Borough of Croydon, on the border with the London Borough of Lambeth and the London Borough of Merton. It shares the postcode London SW16 with nearby Streatham. Norbury is south of Charing Cross.
Waterloo station
Waterloo station, also known as 'London Waterloo', is a major railway terminus in London. It is owned and operated by Network Rail. It is near the South Bank in the London Borough of Lambeth, and in Travelcard Zone 1.
Highbury
Highbury is an area in the London Borough of Islington.
Leyton
Leyton is an area of East London and part of the London Borough of Waltham Forest, northeast of Charing Cross. It borders Walthamstow and Leytonstone; Stratford in Newham; and Homerton and Lower Clapton in the London Borough of Hackney.
There is a professional football team based in Leyton called Leyton Orient F.C.
Tooting
Tooting is a suburb in the London Borough of Wandsworth in south London. It is south south-west of Charing Cross. The area is identified in the London Plan as one of 35 major centres in Greater London.
Atomic radius
The atomic radius of an element is the distance between the nucleus and the edge of the electron cloud.
The atomic radius is rather hard to define, because it is impossible to know where all of the electrons are at a given time.
In the periodic table of the elements, the atomic radius tends to increase as you move down a group because the number of electrons is greater, and so the radius of the circle of electrons in the element is bigger. As you move to the right across a period, the atomic radius tends to decrease due to the shielding effect.
Dale Davis
Dale Davis (born March 25, 1969) is a retired NBA basketball player who played the positions of center and power forward. When he played in the NBA, he played with the Indiana Pacers, the Portland Trail Blazers, the Golden State Warriors, and the Detroit Pistons. He played college basketball at Clemson University.
Underpinning
In construction, underpinning is the process of strengthening and stabilizing the foundation of an existing building or other structure. Underpinning may be needed for a many of reasons:
Epistasis
Epistasis is the interaction between genes at different loci. It was a term invented by William Bateson in 1909.
When Gregor Mendel did his experiments on the sweet pea, he chose seven traits, such as round vs wrinkled peas, and tall vs short plants. He found the plants had pairs of 'factors' (genes) which controlled their appearance (phenotype). However, one pair of factors "never affected the other pairs". But with epistasis, the action of one gene does affect another gene, even one on a different chromosome.
Use of the term has varied somewhat. Its original meaning was quite narrow: for instance, a gene for "no wings" in "Drosophila" will obviously mask genes for any other aspect of the wings. In general, however, epistasis denotes any departure from independence of the effects of different genetic loci.
Holborn tramway station
Holborn tramway station (not to be confused with Holborn tube station) was a tram stop underneath Kingsway in central London. It was part of the Kingsway tramway subway route. When the station opened opened it was named "Great Queen Street".
Services from Angel Islington to Aldwych started on 24 February 1906. Services rom Highbury station to Tower Bridge and from Highbury station to Kennington Gate started on 10 April 1908.
The station closed just after 12.30am on 6 April 1952. Much of the station remains in the disused tunnel but there is no public access.
Epigenetics
Epigenetics is the study of changes in gene activity which are "not" caused by changes in the DNA sequence. It is the study of gene expression, the way genes bring about their phenotypic effects.
These changes in gene activity may stay for the remainder of the cell's life and may also last for many generations of cells, through cell divisions. However, there is no change in the underlying DNA sequence of the organism. Instead, non-hereditary factors cause the organism's genes to behave (express themselves) differently. Epigenetics works by specific mechanisms, such as DNA methylation.
Epigenetic factors may last into adulthood.
A general definition is "the study of... gene activity during the development of complex organisms". Thus "epigenetic" can be used to describe anything other than DNA sequence that influences the development of an organism.
A stricter or narrower definition is "the study of mitotically and/or meiotically heritable changes in gene function that cannot be explained by changes in DNA sequence".
The term "epigenetics" has been used to describe processes which are not heritable. An example is histone modification. So some definitions do not require heritability. Adrian Bird defined epigenetics as "the structural adaptation of chromosomal regions so as to register, signal or perpetuate altered activity states". This definition includes DNA repair or cell division phases, and stable changes across cell generations. It excludes others such as prions unless they affect chromosome function.
The NIH Roadmap Epigenomics Project uses the definition: "...For purposes of this program, epigenetics refers to both heritable changes in gene activity and expression (in the progeny of cells or individuals) and also stable, long-term alterations in the transcriptional potential of a cell".
In 2008, a consensus definition of the epigenetic trait, "stably heritable phenotype resulting from changes in a chromosome without alterations in the DNA sequence", was made at a Cold Spring Harbor meeting.
A reliable and readable account is from "The Guardian" newspaper.
Imprinting in this context means taggimg a gene for the lifetime of the individual. Tagging is the basic operation where cytosine amino acids have a methyl group added by the enzyme DNA methyltransferase. This changes the operation of the gene concerned to be (usually) more favourable to the individual. In general, the advantage of this is to keep the gene output in the most favourable condition for the lifetime of the particular individual.
Imprinting is giving rise to much medical research at present.
Imprinting evolved only about 150 million years ago, and is largely confined to mammals.
The best example of epigenetic changes in eukaryotes is the process of cell differentiation. During morphogenesis, generalised stem cells become the cell lines of the embryo which in turn become fully differentiated cells. In other words, a single fertilized egg cell – the zygote – divides and changes into all the many cell types: neurons, muscle cells, epithelium, blood vessels etc.
As the embryo develops, some genes get switched on, while others are switched off or moderated. This process is called gene regulation. There are many molecules inside the cell nucleus which do the job of adjusting the genes' output.
DNA and histones make up what is called chromatin. Epigenetic modifications to the chromatin are copied during cell division. This produces a line of cells, all of which are alike. This is called a tissue.
Meiosis cancels epigenetic changes, and resets the genome to its baseline state, so the process unfolds in each new generation. There are some exceptions to this rule, but none of these exceptions involve changes to DNA base pair sequences.
This process is different from mutations of the DNA. Genetic mutations change the primary DNA sequence, and mutations can happen in any cell. However, only mutations in cells involved in reproduction can affect the offspring.
Cell differentiation