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George Dantzig

Biography of George Dantzig
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George Dantzig Biography

George Bernard Dantzig (November 8, 1914 – May 13, 2004) was a physicist and mathematician. He was born in Portland, Oregon, United States. His father, Tobias Dantzig, was a mathematician with Russian origin who studied with Henri Poincaré in Paris. Then at the Sorbonne University, he was a professor of Mathematics and started a relationship with his student Anja Ourisson. After a while, they got married and emigrated to the United States. Their firstborn was George. During Dantzig’s youth his father worked as the director of the Department of Mathematics at the University of Maryland, but at the end of World War II, he resigned from this position. On the other side, Anja’s mother was a linguist specializing in Slavic languages.

George was accepted in the University of Maryland to study mathematics in where he would get his B.S. However, he was never satisfied with the teaching methods this university used. In 1937, Dantzig began working in the Bureau of Labor Statistics. Motivated and convinced he started a Doctorate in Statistics at the University of Berkeley, CA where he also felt that the courses were too simple and even meaningless which led him to think about dropping out college. While attending a class in 1939, Professor Jerzy Neyman wrote on the board two complex statistical problems to resolve.

According to Dantzig, the problems were complex, but not impossible to solve. A few days later, he obtained the results. Dantzig received the visit of professor Jerzy Neyman, who pretended, admired by his intelligence, to publish Dantzig’s solution to the problems in a mathematical magazine. Indeed, it was so, years later another researcher, Abraham Wald, complemented and published the last article on this feat in which he explained the conclusion of the second problem, Dantzig was included as the co-author. The solutions to these problems were his doctoral thesis, at the suggestion of Professor Neyman.

Nevertheless, Dantzig interrupted his doctorate shortly after the start of World War II to join the United States Air Force and work with the Combat Analysis Branch of Statistical Control. Soon after, he returned and finished the last stage of his doctorate. After achieving this, he returned to the Air Force to take up the post of Mathematics Advisor of the U. S. Air Force Controller.

He assumed the direction of the Combat Analysis Branch of Statistical Air Force Headquarters of the United States. This work motivated him to perform his great mathematical feats because the Air Force needed to calculate the duration of the stages of a deployment program, training and logistics supply in a more optimal and efficient way. Although he spent a lot of time to find this, he made a great contribution in 1947 when he proposed the Simplex Method to solve a linear programming problem.

In 1952, he was a mathematical researcher at the RAND Corporation, where he implemented linear programming, already studied, in the computers of the corporation. The success at that time was big, and he would keep on doing similar jobs in the universities of Berkeley and Stanford in California, also in centers like the International Institute for Applied Systems Analysis (IIASA) in Vienna. In this last work, he made improvements regarding linear programming problems.

On October 3, 1947, Dantzig met John von Neumann, considered one of the best Mathematician in the world, at the Institute for Advanced Study. Neumann told him about the “Game Theory” a work that was still under construction, carried out in conjunction with Oscar Morgenstern. This was very important because with the acquired knowledge he developed the theory of duality, developed with Fulkerson and Johnson in 1954.

On the other hand, he worked on bifurcation and cutting methods, used in programming to solve big problems. He was responsible for stochastic programming that focuses on the problems of mathematical programming that contain random variables, from this programming, have emerged various models. His knowledge and contribution were reflected in his two books: Linear Programming and Extensions (1963), and a book of two volumes: Linear Programming (1997 and 2003), written with N. Thapa.

He received several recognitions for his great work and his contribution to the military forces of his country. In 1976, President Gerald Ford granted Dantzig the National Medal of Science, his work was recognized during an important ceremony in the White House where he recognized his invention of Linear Programming, which allowed an efficient use of mathematical theory. He also received the Von Neumann Theory Award in 1975, Prize in Applied Mathematics and Numerical Analysis from the National Academy of Sciences in 1977. In Israel, he was awarded the Harvey Prize in Science and Technology from Technion, in 1985. The Academy of Sciences and The US National Academy of Engineering recognized his contribution as a member. A prize was created in his honor given by the Mathematical Programming Societies and SIAM.

The last years of his life had several complications related to his health. Diabetes and cardiovascular problems. Due to this, on May 13, 2004, George Bernard Dantzig died at the age of 90 years accompanied by his family at his residence located in Stanford.

 

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The history of biology

history of biology
CC BY-NC 4.0, Midjourney

The history of biology

The origin of biology dates back to Greek philosophy, when the natural sciences were introduced. Hippocrates was the first to give a biological concept of life, and Aristotle is recognized as the first to classify animals. Aristotle was one of the greatest naturalists of ancient times and his greatest interest was living nature. He was the first great biologist of Europe and formulated the principle that all organisms are adapted to the environment in which they live. In addition, he stated that nature does not release energy unnecessarily, that is, it is parsimonious.

Aristotle, a biologist two thousand years ahead of his time: Some biological observations made by Aristotle took centuries to be confirmed by naturalists, especially those referring to the habits of aquatic animals. Aristotle pointed out that the male of the catfish guarded the eggs laid by the female until the fry were born. For a long time, Aristotle’s assertions, fruit of his observations, were considered to be fables.

 

The origin and evolution of Biology

Biology can be defined in a seemingly simple but precise way as the science that studies life. The historical discussion revolves around what life is.

victorian_biologicalThe etymology of the word Biology is formed by the combination of the Greek terms: “bios” which means life and “logia” which means science.

The first samples of biology go back to the study of living beings and their vital manifestations from ancient times to our time. In this sense, the first classifications of living beings were made according to practical criteria considering usefulness and risk. It was not until the work of Linné (Carlos Linneo) saw the light, in the seventeenth century (Species Plantarum), when a “nature” classification was found.

Although the concept of Biology as a science was born in the 19th century, it studies all aspects or characteristics of living beings such as their chemical composition, reproduction, growth, metabolism, cellular organization and movement.

During the 18th and 19th centuries, biological sciences, such as botany and zoology, became scientific disciplines. It was during these centuries that Lavoisier and other physical scientists began to unite the animate and inanimate worlds through physics and chemistry. Explorer-naturalists, such as Alexander von Humboldt, expanded the fields of science by investigating the interaction between organisms and their environment, initiating biogeography, ethology, and ecology. Later, the cell theory provided a new appearance on the foundations of life.

 

The history of biology is divided into three major stages:

Ancient: theories and discoveries made from prehistory to the Middle Ages. In this sedentary stage of life, man began to observe phenomena of nature such as changes in seasons, tides, rainfall, all this attributed to the action of different gods; this way of explaining natural phenomena through religion and mythology lasted until the 6th century BC. Period in which several Greek philosophers called naturalists appeared, among them were Tales of Mileto, Anaximander, Pythagoras, Jenofanes of Colophon and Parmenides of Elea. Then the first documents of biology appeared, many of them attributed to Hippocrates and he is remembered for the Oath. Aristotle was considered the Father of Zoology; and Galen, last doctor of antiquity, as father of Anatomy.

Modern: With the Renaissance, this era of Biology began that lasted until just before the second decade of the 20th century. Here great biological changes were defined and some apparatuses and tools were invented that made research more optimal. Among the most important advances made in this stage is the invention of the microscope, with which biological structures that were not possible to see at first sight began to be observed.

Modern biology is based on several unifying themes, namely:

  • The Cell Theory.
  • The Theory of Evolution by Natural Selection of Darwin and Wallace.
  • Mendel’s Laws.
  • The Chromosomal Theory of Inheritance.
  • Crick’s Central Dogma on the flow of information.

This stage was also characterized by the use of an experimental work method and the attempt to relate cellular structures to their function. New fields of Biology emerged such as Microbiology and Genetics.

Within this period, some famous researchers stand out in the establishment of the importance of the cell as the fundamental anatomical unit of all living organisms. Among them are:

  • Robert Hooke: the first scientist to use the word “cell”.
  • Robert Brown: Established in 1831 that all cell types have a nucleus.
  • Matthias Schleiden and Theodor Schwann: In 1838, both biologists established that the cell was the fundamental anatomical and structural unit of all living beings. These would be two of the postulates of the Cell Theory.
  • Rudolf Virchow: Proposed the third postulate of the Cell Theory by ensuring in 1858 that the cell is the unit of origin.

Other important researchers of this time were Charles Darwin (theory of evolution); Louis Pasteur (founder of microbiology and creator of the rabies vaccine); Gregor Johann Mendel (Mendel’s laws) and Carlos Linneo (classification of organisms, system of nomenclature).

Molecular: This is the current moment, based on the basis of cellular constitution. Molecular life, which can be called biology of our time in a way, begins in 1920. The invention of the electron microscope, technological advances have made possible great achievements in the different fields of biology, highlighting in particular what has been achieved at the level of Genetic research.

At the beginning of the 20th century, the rediscovery of Mendel’s work led to the rapid development of genetics by Thomas Hunt Morgan and his students, the combination of population genetics and natural classification in modern evolutionary synthesis during 1930. New sciences developed rapidly, especially after James Watson (American biologist) and Francis Crick (British biologist) discovered the structure of DNA in 1953. At the end of the 20th century, new fields such as Genomics and Proteomics inverted this trend, with organic biologists using molecular techniques and investigating the interaction between genes and the environment.

 

Current

In the 21st century, biological sciences contributed as new and classic disciplines previously differentiated as physics in research fields such as biophysics. Advances were made in analytical chemistry and physical instrumentation, optical components, networks, satellites, and computing power for data collection, storage, visualization, and simulation. All of these technological advances allowed for the theoretical and experimental search for molecular biochemistry, biological systems, and ecosystem science. This made global entry possible for the improvement of measurements, complex simulations, analysis, observational content of data over the internet. New research fields in biological sciences emerged such as “bioinformatics” (application of computational technologies to the processing and observation of biological data). “Theoretical biology” (conceptual characterization of biological problems). “Computational genomics” (the use of computational analysis to interpret the biology of genome sequences). “Astrobiology” (combines biology and astronomy to study the origin, evolution, distribution, and future of life in the universe) and “Synthetic biology” (the synthesis of biomolecules, the belief that studies the chemical composition of living beings).

The current moment is that of biotechnology, genetic engineering, and genomics. Contributions from scientists, biochemists, physicists, and engineers are important within this stage, such as Max Perutz and John Kendrew, fundamental in the rapid development of structural biology; E. O. Wilson (biologist, father of biodiversity); Niels Kaj Jerne (immunologist, co-author with Frank Macfarlane Burnet of the clonal selection theory); Moto Kimura (author in 1968 of the neutralist theory of molecular evolution); Paul Berg (biochemist, obtained the first artificial DNA molecule, recombinant DNA, in 1972); Frederick Sanger (discoverer of the structure of insulin); Walter Gilbert (Nobel Prize in Chemistry for his studies on the structure and evolution of DNA sequences) and Carl Woese (creator of the new molecular taxonomy based on the comparison between species of the 16s and 18s mitochondrial RNA.

 

Some branches of Biology are:

  • Anatomy
  • Anthropology
  • Bacteriology
  • Biophysics
  • Marine biology
  • Biomedicine
  • Biochemistry
  • Biotechnology
  • Botany
  • Cytogenetics
  • Cytochemistry
  • Ecology
  • Entomology
  • Ethology
  • Evolution
  • Physiology
  • Genetics
  • Molecular genetics
  • Histology
  • Immunology
  • Microbiology
  • Parasitology
  • Paleontology
  • Taxonomy
  • Virology
  • Zoology
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Willem Einthoven

Willem Einthoven Biography
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Willem Einthoven Biography

Willem Einthoven (May 21, 1860 – September 28, 1927) Physiologist and physician. Nobel Prize in Medicine in 1924. He was born in Semarang, Indonesia. He is well known for his contributions to the development of the electrocardiograph and its clinical application. His father died when they lived in Java, so Willem moved to the University of Utrecht to study medicine.

After finishing his studies he obtained the position of professor at the University of Leiden to deal with the positions of physiology and histology. He took the opportunity to advance an important work in the field of research. He quickly showed himself as a reputable scientist, participated in numerous international scientific forums and the best thing is that by managing several languages ​​he could communicate his ideas faithfully without the need for translators.

For several years he experimented with the rope galvanometer and its utility for the registration of cardiac potentials, and the results obtained were published in an article in the year 1901. Five years later, he masterfully described the clinical applications of the electrocardiogram in Telecardiogramme (1906). After that, he published another article that laid the foundations for the development of this important tool in cardiology analysis. His investigative work was carried out simultaneously with his work as a professor.

Thanks to his work, the galvanometer was used to measure the differences in electrical potential during systolic and diastolic heart contractions and reproduce them graphically. This procedure is known as an electrocardiogram.

Later, he was interested in analyzing how healthy hearts worked and then defining a reference frame, through which attention was paid to the deviations caused by the disease. To sum up, he revolutionized the study, diagnosis, and treatment of cardiac pathologies. In his honor, the lunar crater Einthoven bears his name.

 

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Lucy Wills

Lucy Wills Biography
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Lucy Wills Biography

Lucy Wills (May 10, 1888 – 1964) hematologist and botany. She was born in Sutton Coldfield, United Kingdom. Her family enjoyed a good social and economic position. Therefore, she was able to study at Cheltenham Ladies ’College, an educational institute that offered high educational standards in teaching. Then, she studied Botany and Geology in 1911 but did not receive a Cambridge graduate degree until 1928, when Cambridge began granting degrees to women.

By that time, Wills had admirably managed to graduate as a doctor at the London Royal Free Hospital School of Medicine for Women. From the beginning, he knew that he would devote her knowledge to research and teaching in the Department of Pathological Chemistry of the same center in London. For the year 1928 Margaret Balfour contacted her. For several years she served as chief of pathology until her retirement in 1947.

After her retirement, she worked in South Africa and Fiji studying the effects of nutrition on health. During the last ten years of her life, she was a member of the local government for Chelsea. She started working on macrocytic anemia of pregnancy that primarily affects pregnant women in the tropics, with inadequate diets, this work was developed in several areas of India.

This woman is owed several contributions, such as discovering a nutritional factor in yeast that prevents and cures this disorder: the Wills factor or folate, the natural form of folic acid. In that sense, in the year 1930, she showed that anemia could be reversed with brewer’s yeast, which contains folate.

As part of a recognition of her work and the advancement of medicine, on May 10, 2019, the 131st anniversary of her birth, the Google search engine commemorated Wills with a Doodle available for North America, parts of South America and Europe, Israel, India, and New Zealand. Her knowledge changed the face of prenatal preventive care for women around the world.

 

WORKS

  • Studies on blood and urinary chemistry during pregnancy: blood sugar curves.
  • Studies in pernicious anemia of pregnancy (1930). This research has 4 parts.
  • Treatment of “pernicious anemia” of pregnancy and “tropical anemia” with special reference to yeast extract as a healing agent.
  • The nature of the hemopoietic factor in Marmite.
  • A new factor in the production and cure of certain macrocytic anemias.
  • Tropical macrocytic anemia: its relationship with pernicious anemia.
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Claude Bernard

Claude Bernard Biography
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Claude Bernard Biography

Claude Bernard (July 12, 1813 – February 10, 1878) physiologist. He was born in Saint-Julien, France. The top representative of the French physiology of the 19th century. His life was dedicated to studying the nervous regulation of salivary secretion, pancreatic digestion, and glycogenic liver function. He is admired for having discovered vasomotor innervation and creating the concept of internal secretion. His contributions to experimental pharmacology are also salvageable.

Bernard at nineteen entered as a clerk in a pharmacy in Vaise, a suburb of Lyon. He liked literature so he wrote a drama entitled Arthur de Bretagne, he went to Paris; but then he started studying medicine, leaving literature aside. At first, he had the guidance of the physiologist François Magendie, who was a trainer, and soon gave proof of his genius. In 1843 he could already demonstrate the glycogenic function of the liver. He was an assistant to Magendie and professor of physiology at Collège de France. In the year of 1853, he obtained the title of doctor of science with the thesis Investigations about a new function of the liver, considered as a producing organ of sugary matter.

The following year he was a professor of experimental medicine at the Collège de France. Years later, and thanks to the knowledge acquired, he wrote Introduction to the study of experimental medicine (1865) allowed him to be part of the French Academy; this year he was entrusted with the chair of general physiology of the Sorbonne Natural History Museum, and in 1869 he was appointed member of the Imperial Senate of Napoleon III. In 1870 his intellectual vitality was affected by a kidney disease contracted because of the cold and humidity of his laboratory.

This French defended the determinism linked to neo-vitalism. He also studied, in addition to hepatic glycogenesis, the sympathetic nervous system and poisons. Among his works are Leçon sur la physiologie expérimentale appliquée a la médecine (1856), Les propriétés des tissus vivants (1866) and Leçon Sur Les phenomènes de la vie (1878).

In broad strokes, his works advocated naturalistic principles and thus generated a great influence that he exerted on the naturalist movement, mainly in Zola. Bernard establishes the rules of medicine that is true science and method, must have a solid foundation. For hi medicine must be like physics and chemistry, a science that undergoes an experimental method. But experience is not proven simply by the facts, without being guided by a precise conviction; rather, it must be rigorous and complete experimentation. So, the philosophical and theological yoke is excluded, admitting a personal scientific authority.

Thus, Bernard says, the hypotheses will encourage discoveries and experimentation serves as a guide. Émile Zola developed in his thinking of naturalist novelist Bernard’s famous scientific premises; his essay The experimental novel represents the attempt to apply the principles of physiology to a conception of art. Unfortunately, he died on February 10, 1878. He is remembered for being one of the referents of experimental physiology of the nineteenth century, and, at the same time, one of the most illustrious thinkers of the time in Europe. The medicine had many advances in an anomaly that affects the sympathetic nerves of the face, it was called Claude Bernard-Horner syndrome.

Similarly, he contributed to the development of therapeutics, diabetes, indications of bleeding, detoxification by carbon monoxide through mechanical ventilation, the treatment of anemia with iron lactate, the decrease in body temperature through physical means, treatment of alcohol intoxication, morphine applications, the effects of carbon dioxide, intravenous administration of physiological serum, cardiopulmonary resuscitation techniques, among others.

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Adolf Von Baeyer

Adolf Von Baeyer Biography
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Adolf Von Baeyer Biography

Adolf von Baeyer (October 31, 1835 – August 20, 1917) Chemist and Nobel Prize in Chemistry (1905). He was born in Berlin, Germany. He is recognized for the research he carried out on the structure and artificial synthesis of numerous organic compounds. In short, he discovered phenolphthalein and fluorescein. Baeyer is known primarily for the synthesis of indigo.

His father was a military man named Jakob Baeyer, and creator of the European geodetic measurement system. From an early age, Adolf showed great interest in chemistry. His curiosity and intelligence allowed him to synthesize and isolate for the first time a double copper salt with only twelve years of age. Upon finishing his high school studies he entered the University of Berlin to study physics and mathematics. In 1856 he joined the laboratory of Robert Bunsen in Heidelberg. A year later he published the results of several studies on methyl chloride (CH3Cl). In the year of 1858, he was the first research assistant of August Kekulé. The knowledge of this chemist was very helpful in organic chemistry.

Baeyer began studies on uric acid that led to the synthesis of barbituric acid. Then, he served as a professor at the University of Berlin in 1860. Thanks to his long days in the laboratory he discovered that when a complex molecule was subjected to high temperatures in the presence of zinc dust, it could be fragmented. Two of his disciples: Carl Graebe and Karl Liebermann, unraveled the structure of alizarin, a red dye from the root of the tinctorum used to dye the uniforms of the French army.

After seventeen years of studies and research, he found the synthesis of indigo, an intense blue tincture obtained from the leaves and stems of the Indigofera tinctorum. So, he made a synthesis between 1878 and 1882. They were not used for commercial purposes (although, today this dye is necessary for the textile industry). Thanks to this he received the Davy Medal of the Royal Society of London in 1881.

In 1868 he married Adelheid Bendemann. In 1871 he obtained a place at the University of Strasbourg, which he left two years later to start as Professor at the University of Munich. He enjoyed a modern laboratory. He conducted studies on acetylene and polyacetylene, works with benzene and cyclic terpenes, on the other hand, defined the Theory of Torsion, basically, this allows us to understand why those of five and six carbons are the most stable existing cyclic compounds. His work and scientific career were recognized in 1905 with the Nobel Prize in chemistry for his contribution to organic chemistry through chemical dyes. That same year, he turned seventy birthdays, and several of his articles were published in important scientific journals.

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