SUMMARY / RELATED TOPICS

Robert Watson-Watt

Sir Robert Alexander Watson-Watt, KCB, FRS, FRAeS was a British pioneer of radio direction finding and radar technology. Watt began his career in radio physics with a job at the Met Office, where he began looking for accurate ways to track thunderstorms using the radio signals given off by lightning; this led to the 1920s development of a system known as huff-duff. Although well publicized at the time, the system's enormous military potential was not developed until the late 1930s. Huff-duff allowed operators to determine the location of an enemy radio in seconds and it became a major part of the network of systems that helped defeat the U-boat threat, it is estimated. In 1935 Watt was asked to comment on reports of a German death ray based on radio. Watt and his assistant Arnold Frederic Wilkins determined it was not possible, but Wilkins suggested using radio signals to locate aircraft at long distances; this led to a February 1935 demonstration where signals from a BBC short-wave transmitter were bounced off a Handley Page Heyford aircraft.

Watt led the development of a practical version of this device, which entered service in 1938 under the code name Chain Home. This system provided the vital advance information that helped the Royal Air Force win the Battle of Britain. After the success of his invention, Watson-Watt was sent to the US in 1941 to advise on air defence after Japan’s attack on Pearl Harbor, he continued to lead radar development for the War Office and Ministry of Supply. He was elected a Fellow of the Royal Society in 1941, was given a knighthood in 1942 and was awarded the US Medal for Merit in 1946. Born in Brechin, Scotland, on 13 April 1892 Watson-Watt was a descendant of James Watt, the famous engineer and inventor of the practical steam engine. After attending Damacre Primary School and Brechin High School, he was accepted to University College, Dundee. Watson-Watt had a successful time as a student, winning the Carnelley Prize for Chemistry and a class medal for Ordinary Natural Philosophy in 1910, he graduated with a BSc in engineering in 1912, was offered an assistantship by Professor William Peddie, the holder of the Chair of Physics at University College, Dundee from 1907 to 1942.

It was Peddie who encouraged Watson-Watt to study radio, or "wireless telegraphy" as it was known, who took him through what was a postgraduate class of one on the physics of radio frequency oscillators and wave propagation. At the start of the Great War Watson-Watt was working as an assistant in the College's Engineering Department. In 1916 Watson-Watt wanted a job with the War Office, but nothing obvious was available in communications. Instead he joined the Meteorological Office, interested in his ideas on the use of radio for the detection of thunderstorms. Lightning gives off a radio signal as it ionizes the air, his goal was to detect this signal to warn pilots of approaching thunderstorms; the signal occurs across a wide range of frequencies, could be detected and amplified by naval longwave sets. In fact, lightning was a major problem for communications at these common wavelengths, his early experiments were successful in detecting the signal and he proved to be able to do so at ranges up to 2,500 km.

Location was determined by rotating a loop antenna to maximise the signal, thus "pointing" to the storm. The strikes were so fleeting that it was difficult to turn the antenna in time to positively locate one. Instead, the operator would develop a rough average location. At first, he worked at the Wireless Station of Air Ministry Meteorological Office in Aldershot, Hampshire. In 1924 when the War Department gave notice that they wished to reclaim their Aldershot site, he moved to Ditton Park near Slough, Berkshire; the National Physical Laboratory was using this site and had two main devices that would prove pivotal to his work. The first was an Adcock antenna, an arrangement of four masts that allowed the direction of a signal to be detected through phase differences. Using pairs of these antennas positioned at right angles, one could make a simultaneous measurement of the lightning's direction on two axes. Displaying the fleeting signals was a problem; this was solved by the second device, the WE-224 oscilloscope acquired from Bell Labs.

By feeding the signals from the two antennas into the X and Y channels of the oscilloscope, a single strike caused the appearance of a line on the display, indicating the direction of the strike. The scope's "slow" phosphor allowed the signal to be read long after the strike had occurred. Watt's new system was the topic of an extensive paper by Watt and Herd; the Met and NPL radio teams were amalgamated in 1927 to form the Radio Research Station with Watt as director. Continuing research throughout, the teams had become interested in the causes of "static" radio signals, found that much could be explained by distant signals located over the horizon being reflected off the upper atmosphere; this was the first direct indication of the reality of the Heaviside layer, proposed earlier but at this time dismissed by engineers. To determine the altitude of the layer, Watt and others developed the'squegger' to develop a'time base' display, which would cause the oscilloscope's dot to move smoothly across the display at high speed.

By timing the squegger so that the dot arrived at the far end of the display at the same time as expected signals reflected

Heterobasidion irregulare

Heterobasidion irregulare is a tree root rotting pathogenic fungus that belongs to the genus Heterobasidion, which includes important pathogens of conifers and other woody plants. It has a wide host and geographic range throughout North America and causes considerable economic damage in pine plantations in the United States; this fungus is a serious worry in eastern Canada. Heterobasidion irregulare has been introduced to Italy where it has been responsible for extensive tree mortality of stone pine. Due to the ecology, disease type, host range/preference, interfertility group, genetic information, H. irregulare was designated a new species and distinguished from Heterobasidion occidentale. Many woody plant species have been reported as hosts for H. irregulare. Hosts consist of pines and some other conifers and hardwoods, including ponderosa pine, shortleaf pine, red pine, incense-cedar, western juniper, Manzanita. Heterobasidion irregulare causes both below-ground symptoms. Above-ground symptoms of infected trees consist of reduced height growth, patches of dead and declining trees, wind-thrown trees, reduced shoot and diameter growth, resin-soaking at the root collar.

Additionally, the crown may become thin and foliage becomes chlorotic. The characteristic symptom of most tree root disease, including this type, is a disease center; this occurs when the fungus has infected one tree and spreads through the roots to other trees and kills them too. This creates a pattern of old dead trees in the center of the pocket and progressively newer dead, chlorotic healthy trees in a circular area. Below-ground symptoms of H. irregulare include excessive pitch production, white root decay, root lesions. Signs include the formation of white mycelia between bark scales followed by conks that form in the duff layer at the base of the tree or stump; the fruit bodies can form as "foam" on the ground rising from roots under the surface. The disease cycle of Heterobasidion irregulare begins with natural wounds on trees or cut stumps. Basidiospores are land on tree wounds. Most spores land within 100 metres of the fruiting bodies; the spores germinate and the mycelia, or vegetative structure of the fungus, grows into the wood.

The mycelia colonizes the wood by decomposing the lignin and cellulose, producing a stringy white rot. It spreads from tree to tree by killing trees in an ever-widening circle; the sexual reproductive structures of the fungus, annual or perennial basidiocarps, appear on decomposing stumps and at the base of dead trees and release spores in summer and fall to mid-winter. The highest sporulation occurs from late summer to; when the conk temperatures are above freezing the spores of the fungus are released and carried by wind currents to land in open wounds or stumps of cut trees. The fungus can survive freezing temperatures both as mycelia and as basidiocarps, overwinters in the roots and stem tissue of trees; the mycelia produce infectious conidia. When the fungus has obtained enough nutrients it grows a basidiocarp on the outside of a trunk or stump of a tree in the eastern US or inside a hollow stump in the western US. Various abiotic factors attribute to the ability of Heterobasidion irregulare to cause disease on trees.

Factors such as gaseous regime, pH of the soil, moisture content, may affect fungal growth. Disease is most severe on alkaline, or former agricultural soils. H. irregulare grows best on well drained sandy soils, which are now farm fields that have been converted into plantations in the southern US. Plantations favor this fungus because it enters the plant through a wound or cut surface and spreads by the roots. Research on temperature requirements for germination and spore production is being conducted, it is known however, that H. irregulare is able to germinate at temperatures as low as 8 °C. The best strategy to manage this disease is to avoid infection of stumps. To do this, do not cut trees at major sporulation times, which are summer to late fall, treat fresh stumps with protectants such as borax, registered as cellu-treat or sporax, either as a powder or in aqueous form; these treatments are most effective if done after stump is created. Other control measures include: use wide spacing when planting to reduce the need for thinning and reduce the potential root grafts, thin only when spores are less abundant, plant tree species that are less susceptible.

Another strategy is to avoid logging injuries as the spores enter through such injuries and infect and kill the tree and begin a disease center. Once the fungus is in the stand there is nothing that can be done about it except expensive stump removal and prevention of new infections. There are bio-controls used in Europe against the Heterobasidion species found there. However, they are not approved for use in the United States and it is uncertain whether they work on Heterobasidion irregulare because of the recent naming of this species, not much research has been done outside of the US on its reaction to biocontrols; this disease is economically important because of its effect on timber species in plantations in the Midwest and Southeast in the United States. It destroys commercially viable trees and causes losses both from reduction of marketable wood and increased cost of treatment

Club Melilla Baloncesto

Club Melilla Baloncesto is a professional basketball team based in Melilla that plays in the LEB league. This is the only team in Spain; the team's home arena is the Pabellón Javier Imbroda Ortiz, with a capacity of up to 3,800 spectators. Club Melilla Baloncesto was founded in 1991 as a merge of CB Gran Tercio. In its first season, played in the second division with the name of Unicaja Melilla as an affiliated team of Liga ACB club Unicaja. Despite being relegated, remained in the league after its expansion to 31 teams, that allowed the club to continue playing in the second division, indeed when the Liga EBA was created. In 1996, Melilla became one of the founding clubs of the Liga LEB. In 1999, the club achieved their first title by winning the Copa Príncipe de Asturias after defeating Menorca Bàsquet in the final, is close to promote to the Liga ACB, but was eliminated in the last round of the playoffs by Breogán Universidade. In 2001, Melilla clinched their segund Copa Príncipe de Asturias, this time beating Bàsquet Manresa in the Final Four played at home.

After several years of consolidation in the league, in 2008 the club reached again the last round of the promotion playoffs but lost to Lucentum Alicante in the last round. One year despite winning their third Cup and despite being the top seeded team, was eliminated in the semifinals of the promotion playoffs to Ford Burgos. In 2013 the club suffered their first relegation from the LEB Oro, but remained in the league after achieving a vacant place. Three years in 2016, the club clinched the promotion to Liga ACB, but resigned to join the league resigned to promote due to the impossibility to fulfill the requirements. Copa Príncipe de Asturias: 1999, 2001, 2010 All-LEB Oro Team Eduardo Hernández-Sonseca – 2016 Federación Española de Baloncesto Melilla Baloncesto Official Site