Monday, September 1, 2014

Sergei Winogradsky and the Science of Bacteriology

Sergei Winogradsky
(1856 - 1953)
On September 1, 1856, Ukrainian microbiologist, ecologist and soil scientist Sergei Nikolaievich Winogradsky was born, who pioneered the cycle of life concept. He helped to establish bacteriology as a major biological science.

Sergei Winogradsky was born in Kiev, which belonged to the Russian Empire. The young man finished his secondary education with the gold medal and entered the Imperial Conservatoire of Music in St Petersburg in 1875 to study piano. However, he decided to study chemistry and botany about two years later and was admitted to the University of Saint Petersburg, where he studied under Nikolai Menshchutkin and Andrei Sergeevich Famintzin. After receiving his master degree in 1884, Winogradsky continued his career at the University of Strasbourg and earned a great reputation for his work on sulfur bacteria. Winogradsky developed a method of culturing Beggiatoa by imitating its natural environment on glass slides and silica gel and he observed that the cells were rods and not, as it was previously assumed, pleomorphic [1].

The scientist settled in Zurich around 1888 and began investigating the process of nitrification, identifying the genera Nitrosomonas and Nitrosococcus, which oxidizes ammonium to nitrite, and Nitrobacter, which oxidizes nitrite to nitrate. Winogradsky's interest in nitrification continued throughout his career and he isolated several genera of nitrifying bacteria. The type species for the genus Nitrobacter, N. winogradskyi was named after the scientist. Years later, Winogradsky’s daughter Helen worked on nitrogen-oxidizing bacteria at the Pasteur Institute. She isolated and described the new genera Nitrosogloea and Nitrosocystis. In 1933, she coauthored a paper with her father on Nitrosospira [1,2].

Winogradsky returned to St. Petersburg around 1891 and was shortly after appointed director of the Institute of Experimental Medicine and editor of the journal, Archives of Science. In this period, he identified the obligate anaerobe Clostridium pasteurianum, which is capable of fixing atmospheric nitrogen and he was elected honorary member of the Moscow Society of Naturalists. Winogradsky retired from his post in 1905 and accepted a position as head of agricultural bacteriology at the Pasteur Institute at an experimental station at Brie-Comte-Robert near Paris, France. He retired from his active work life in 1940.

At yovisto, you may be interested in a video lecture about the History of Microbiology by Gilles Bolduc.

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Sunday, August 31, 2014

Sir Bernard Lovell and the Radioastronomy

Sir Bernard Lovell (1913-2012)
On August 31, 1913, English physicist and radio astronomer Sir Bernard Lovell was born. He was a pioneer in radar and radio telescopes and especially renowned for creating the Jodrell Bank radio telescope, the only antenna that could track rockets in space in the early years of the space race between the United States and the Soviet Union.

Born at Oldland Common, Bristol in 1913, as the son of Gilbert and Emily Laura Lovell, Bernard Lovell's childhood hobbies and interests included cricket and music – mainly the piano. He attended Kingswood Grammar School, now King's Oak Academy, before he studied physics at the University of Bristol, where he obtained a bachelor of science degree in 1934, and a PhD in 1936 on the electrical conductivity of thin films At this time he also received lessons from Raymond Jones, a teacher at Bath Technical School and later organist at Bath Abbey. The church organ was one of the main loves of his life, apart from science and cricket. After a year as an assistant lecturer in physics at the University of Manchester, he became a member of the cosmic-ray research team at that institution, working in this capacity until the outbreak of World War II in 1939.

During World War II Lovell worked for the Air Ministry, doing valuable research in the use of radar for detection and navigation purposes for which he was named an Officer of the Order of the British Empire (OBE) in 1946.[1] Returning to the University of Manchester in 1945 as a lecturer in physics, Lovell acquired a surplus army radar set for use in his research on cosmic rays. Because interference from the surrounding city hampered his efforts, he moved the equipment, which included a searchlight base, to Jodrell Bank, an open field located about 30km south of Manchester near Goostrey in Cheshire. Shortly thereafter authorities at the university agreed to provide him with a permanent establishment at the site, which already belonged to the university’s botany department, and to sponsor the construction of his first radio telescope, for which he used the searchlight base as a mounting.

In the course of his experiments, he was able to show that radar echoes could be obtained from daytime meteor showers as they entered the Earth's atmosphere and ionised the surrounding air. With University funding, he constructed the then-largest steerable radio telescope in the world, which now bears his name – the Lovell Telescope. Completed in 1957, the telescope – known initially as Mark 1 and renamed the Lovell Telescope on its 30th anniversary – dominates the surrounding countryside and continues to make huge contributions to the science of astronomy.[2] The Mark 1 telescope was the only instrument that could both detect the first Soviet and American satellites and transmit instructions to them. Oddly enough as it now seems, the need for such a telescope had escaped both the telecommunications industry and the military leaders of both superpowers.

Despite its spectacular success, which included tracking the Sputnik 1 satellite mission in 1957, Lovell went through a lot of trubles concerning the funding of the radio telescope. The main problem was to find sufficient funds to meet the rising costs of the project at times of government cuts. Thus in 1955 the project found itself £250,000 in debt. The Department of Scientific and Industrial Research agreed to find half if Lovell could raise the rest. A public appeal failed to raise more than £65,000 and it required a strong public press campaign to move the Treasury to meet the outstanding costs in 1960, three years after the telescope was first used. [3]

In 1951, Lovell became professor of radio astronomy at Manchester University and the founder and first director of Jodrell Bank Experimental Station . In 1958 he gave the Reith Lectures, for the BBC, entitled The Individual and the Universe. Beginning in 1958, Lovell carried out much research on the characteristics of flare stars. In 1960, he began collaborating with Fred Whipple of the Smithsonian Astrophysical Observatory in this work. In 1955 he was elected a fellow of the Royal Society; in 1960 he received the Royal Medal of the society. Lovell was knighted in 1961 for his important contributions to the development of radio astronomy,

At yovisto you can learn more about radio astronomy in the lecture of Prof. Walter Briskin from Princeton Institute of Advanced Studies on 'AstroGPU - Real-time Digital Signal Processing in Radio-Astronomy'

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Saturday, August 30, 2014

Fred Whipple and the Dirty Snowballs

Fred Whipple (1906-2004)
On August 30, 2004, American astronomer Fred Lawrence Whipple passed away. Amongst his achievements, he discovered some asteroids and comets, came up with the "dirty snowball" cometary hypothesis, and designed the Whipple shield.

Frank Whipple was born on November 5, 1906, in Red Oak, Iowa, as the son of a farmer. An early bout with polio ended his ambition of being a professional tennis player. Whipple studied at Occidental College in Southern California, then majored in mathematics at the University of California at Los Angeles, graduating in 1927. Intrigued by an astronomy course he encountered, Whipple changed his area of study to astronomy and earned a doctorate degree in 1931.[1] While in graduate school, he helped map the orbit of the then newly discovered dwarf planet Pluto. His first job out of college was at Harvard University, where he inspected the telescopes’ photographic plates to make sure the cameras were operating correctly. He studied the trajectories of meteors, confirming that they originated within the solar system rather than from interstellar space. In 1933, he discovered the periodic comet 36P/Whipple and the asteroid 1252 Celestia. He also discovered or co-discovered five other non-periodic comets.

Whipple found that nearly all visible meteors are made up of fragile material from comets, and that none can be shown to come from beyond the solar system. During World War II he co-invented chaff—aluminum fragments—to foil radar and protect planes.[2] He was awarded a Certificate of Merit for this in 1948. In 1950, in the same year he became professor of astronomy at Harvard, Whipple proposed his famous “dirty snowball” model for comet nuclei (originally he it"icy conglomerate" hypothesis of comet composition). He suggested that comets have icy cores inside thin insulating layers of dirt, and that jets of material ejected as a result of solar heating were the cause of orbital changes. The basic features of this hypothesis were confirmed in 1986 when spacecraft flew past comet Halley, however the exact amount (and thus the importance) of ices in a comet is an active field of research, with most of the recently obtained data pointing to a low contribution of ices to a comet's mass. [2]

Whipple also anticipated the era of artificial satellites and organized the members of Operation Moonwatch to track them. These groups were the only ones prepared and ready to make observations when the Soviet Union unexpectedly launched Sputnik I in 1957. His work on tracking artificial satellites led to improved knowledge of the shape of the earth and greatly improved positions on earth. Whipple directed the Smithsonian Astrophysical Observatory (SAO) from 1955 to 1973, before it joined with the Harvard College Observatory to form the Harvard-Smithsonian Center for Astrophysics (CfA). In the late 1960s, Whipple selected Mount Hopkins in southern Arizona as the site for a new SAO astronomical facility. Whipple was part of the group that initiated a novel and low-cost approach to building large telescopes first realized in the construction of the Multiple Mirror Telescope, a joint project of SAO and the University of Arizona. Mt. Hopkins Observatory was renamed Fred Lawrence Whipple Observatory in 1981. [3] Whipple died in 2004, aged 97.

At yovisto you can learn more about astronomy in a popular lecture by Neil deGrasse Tyson at the University of Washington in Seattle.

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If you like the daily blog posts of yovisto about the history of science, please support us by clicking on the amazon links and making your next amazon purchase via our offered links. Nevertheless, please do also support your local (real world) bookstore at the corner of the street.