June 22

Jamshīd al-Kāshī was born around 1380 in Kashan, Persia. He authored the astronomical work “The Treatise of the Circumference” with tables of sines and tangents. Al-Kāshī calculated π to several decimal places using innovative iterative methods. He served at the Samarkand observatory under Ulugh Beg, advancing observational astronomy. His contributions influenced later mathematicians and remain studied by historians of science.

Born in 1819, Pierre Ossian Bonnet was a pioneering French mathematician and professor at the University of Toulouse. He is celebrated for the Gauss–Bonnet theorem, a fundamental result linking curvature and topology in geometry. Bonnet also made significant advances in differential equations and surface theory. As an educator, he influenced a generation of mathematicians through his lectures and published works. His rigorous approach and breakthroughs helped shape modern differential geometry. He passed away on June 22, 1892, solidifying his reputation as a foundational figure in mathematics.

Born in 1849 in Düsseldorf, Felix Klein was a transformative figure in 19th-century mathematics. He developed the Erlangen program, unifying geometry through group theory and symmetries. Klein introduced the concept of the Klein bottle, a non-orientable surface that challenged topological concepts. As a professor at the University of Erlangen and later Göttingen, he mentored future mathematicians and reformed mathematical education. His textbook "Elementary Mathematics from an Advanced Standpoint" influenced teaching methods worldwide. He passed away on June 22, 1925, leaving a profound impact on geometry and mathematical pedagogy.

Born in Lwów in 1866 and educated at the University of Lwów. He specialized in modern Polish history, publishing seminal works on the partitions. In 1919, he was appointed as Poland’s first envoy to France, strengthening diplomatic ties. He founded the Askenazy School, influencing generations of historians. His research combined archival rigor with a passion for national identity. He died in 1935, leaving a lasting legacy in historical scholarship.

Born in Berlin in 1882, he studied physics and philosophy. He became professor at the University of Vienna in 1922. He founded the Vienna Circle, promoting analytic philosophy and scientific rigor. His work 'General Theory of Knowledge' reshaped epistemology and philosophy of science. He advocated for a verification principle, influencing generations of thinkers. He was tragically assassinated by a former student in 1936.

Đặng Thùy Trâm was a dedicated Vietnamese surgeon who served with the 108th Field Hospital during the Vietnam War. Born in 1942, she treated countless soldiers and civilians under challenging conditions. In her private journals, she documented the daily realities of combat, capturing both hope and hardship with honesty and compassion. After her death in 1970, her diaries were discovered and later published, providing a unique perspective on the human cost of war. Her writings have since become an important part of Vietnam's historical narrative.

Ilya Frank shared the 1958 Nobel Prize in Physics for his contributions to the discovery and interpretation of Cherenkov radiation. After graduating from Leningrad University, he conducted groundbreaking research at the Lebedev Physical Institute. His work helped deepen the understanding of nuclear reactions and particle detection. Frank held academic positions throughout the Soviet Union, mentoring a generation of physicists. His scientific achievements laid important foundations for modern high-energy physics.

Bob Bemer pioneered many of the standards that underpin modern computing, most notably proposing the ASCII character set in the early 1960s. He worked at IBM, UNIVAC, and NASA, contributing to the development of COBOL and early programming practices. Bemer introduced the concept of the escape sequence and advocated for software portability across platforms. He served on numerous standards committees and authored influential technical papers. His legacy endures in the ubiquitous encoding systems and interoperability standards used today.

Born in Leningrad, she studied medicine at the Leningrad Medical Institute. Her early work focused on the electrophysiology of human brain responses. She became director of the Institute of Human Brain in St. Petersburg. She published over 300 scientific papers and multiple monographs. Her research advanced understanding of psychological processes and brain activity. She received the Lenin Prize and multiple state honors for her contributions. Her work laid the foundations for modern neuropsychology in Russia.

Born in Sidon, Lebanon, he earned his doctorate at the University of Washington. He served as a professor of Near Eastern studies at Johns Hopkins University. His books, including 'The Arab Predicament' and 'The Dream Palace of the Arabs', became definitive works on Arab politics. He was a senior fellow at the Council on Foreign Relations and advised policymakers. His commentary appeared in major publications and on news networks worldwide. He bridged scholarship and journalism, making complex issues accessible to a broad audience. His work shaped Western understanding of Middle Eastern affairs for decades.

Yves Coppens was a French anthropologist renowned for his research on human evolution. He co-led the 1974 expedition that discovered the hominin fossil 'Lucy' in Ethiopia. His analyses of Laetoli footprints advanced understanding of early bipedalism. Coppens held professorships at institutions including the Collège de France. He authored influential works on paleoanthropology for both academic and general audiences. He served as a member of the French Academy of Sciences and received prestigious awards. His pioneering contributions helped shape the field of human evolutionary studies.

Harry Markowitz was an American economist best known for developing Modern Portfolio Theory. His 1952 paper introduced the concept of portfolio diversification and risk optimization. Markowitz shared the 1990 Nobel Memorial Prize in Economic Sciences for his groundbreaking research. He served as a professor at several universities, including UCLA and the University of Pennsylvania’s Wharton School. His work laid the foundation for modern financial economics and investment management. Markowitz also contributed to programming languages and software for financial analysis. He remained active in research well into his 90s, influencing generations of economists.