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🔗 Technology 🔗 Physics 🔗 Radio 🔗 Astronomy 🔗 Engineering

In engineering, the terahertz gap is a frequency band in the terahertz region of the electromagnetic spectrum between radio waves and infrared light for which practical technologies for generating and detecting the radiation do not exist. It is defined as 0.1 to 10 THz (wavelengths of 3 mm to 30 µm). Currently, at frequencies within this range, useful power generation and receiver technologies are inefficient and unfeasible.

Mass production of devices in this range and operation at room temperature (at which energy k·T is equal to the energy of a photon with a frequency of 6.2 THz) are mostly impractical. This leaves a gap between mature microwave technologies in the highest frequencies of the radio spectrum and the well developed optical engineering of infrared detectors in their lowest frequencies. This radiation is mostly used in small-scale, specialized applications such as submillimetre astronomy. Research that attempts to resolve this issue has been conducted since the late 20th century.

🔗 Human rights 🔗 Soviet Union 🔗 Crime 🔗 Death 🔗 Philosophy 🔗 Discrimination 🔗 Philosophy/Ethics 🔗 Soviet Union/history of Russia 🔗 Soviet Union/Russia 🔗 Ukraine 🔗 Ethnic groups

The Holodomor (Ukrainian: Голодомо́р, romanized: Holodomór; derived from морити голодом, moryty holodom, 'to kill by starvation'), also known as the Terror-Famine and sometimes referred to as the Great Famine was a famine in Soviet Ukraine from 1932 to 1933 that killed millions of Ukrainians. The term Holodomor emphasises the famine's man-made and intentional aspects such as rejection of outside aid, confiscation of all household foodstuffs and restriction of population movement. As part of the wider Soviet famine of 1932–33 which affected the major grain-producing areas of the country, millions of inhabitants of Ukraine, the majority of whom were ethnic Ukrainians, died of starvation in a peacetime catastrophe unprecedented in the history of Ukraine. Since 2006, the Holodomor has been recognized by Ukraine and 15 other countries as a genocide of the Ukrainian people carried out by the Soviet government.

Early estimates of the death toll by scholars and government officials varied greatly. According to higher estimates, up to 12 million ethnic Ukrainians were said to have perished as a result of the famine. A United Nations joint statement signed by 25 countries in 2003 declared that 7–10 million perished. Research has since narrowed the estimates to between 3.3 and 7.5 million. According to the findings of the Court of Appeal of Kyiv in 2010, the demographic losses due to the famine amounted to 10 million, with 3.9 million direct famine deaths, and a further 6.1 million birth deficits.

Whether the Holodomor was genocide is still the subject of academic debate, as are the causes of the famine and intentionality of the deaths. Some scholars believe that the famine was planned by Joseph Stalin to eliminate a Ukrainian independence movement.

🔗 Medicine 🔗 China 🔗 Plants 🔗 Pharmacology 🔗 Psychoactive and Recreational Drugs

For over two millennia, texts in Chinese herbology and traditional Chinese medicine have recorded medicinal plants that are also hallucinogens and psychedelics. Some are familiar psychoactive plants in Western herbal medicine (e.g., Chinese: 莨菪; pinyin: làngdàng, i.e. Hyoscyamus niger), but several Chinese plants have not been noted as hallucinogens in modern works (e.g.,Chinese: 雲實; pinyin: yúnshí; lit. 'cloud seed', i.e. Caesalpinia decapetala). Chinese herbals are an important resource for the history of botany, for instance, Zhang Hua's c. 290 Bowuzhi is the earliest record of the psilocybin mushroom xiàojùn 笑菌 (lit. "laughing mushroom", i.e. Gymnopilus junonius).

🔗 Physics 🔗 Astronomy

In astrophysics and physical cosmology, Olbers' paradox, named after the German astronomer Heinrich Wilhelm Olbers (1758–1840), also known as the "dark night sky paradox", is the argument that the darkness of the night sky conflicts with the assumption of an infinite and eternal static universe. In the hypothetical case that the universe is static, homogeneous at a large scale, and populated by an infinite number of stars, any line of sight from Earth must end at the surface of a star and hence the night sky should be completely illuminated and very bright. This contradicts the observed darkness and non-uniformity of the night.

The darkness of the night sky is one of the pieces of evidence for a dynamic universe, such as the Big Bang model. That model explains the observed non-uniformity of brightness by invoking spacetime's expansion, which lengthens the light originating from the Big Bang to microwave levels via a process known as redshift; this microwave radiation background has wavelengths much longer than those of visible light, and so appears dark to the naked eye. Other explanations for the paradox have been offered, but none have wide acceptance in cosmology.

🔗 Spaceflight 🔗 Military history 🔗 Military history/North American military history 🔗 Military history/United States military history 🔗 Military history/Military science, technology, and theory 🔗 Moon 🔗 Military history/Cold War 🔗 Cold War 🔗 Solar System 🔗 Solar System/Moon

Project A119, also known as A Study of Lunar Research Flights, was a top-secret plan developed in 1958 by the United States Air Force. The aim of the project was to detonate a nuclear bomb on the Moon, which would help in answering some of the mysteries in planetary astronomy and astrogeology. If the explosive device detonated on the surface, not in a lunar crater, the flash of explosive light would have been faintly visible to people on Earth with their naked eye, a show of force resulting in a possible boosting of domestic morale in the capabilities of the United States, a boost that was needed after the Soviet Union took an early lead in the Space Race and was also working on a similar project.

The project was never carried out, being cancelled primarily out of a fear of a negative public reaction, with the potential militarization of space that it would also have signified, and because a Moon landing would undoubtedly be a more popular achievement in the eyes of the American and international public alike. A similar project by the Soviet Union also never came to fruition.

The existence of the US project was revealed in 2000 by a former executive at the National Aeronautics and Space Administration (NASA), Leonard Reiffel, who led the project in 1958. A young Carl Sagan was part of the team responsible for predicting the effects of a nuclear explosion in vacuum and low gravity and in evaluating the scientific value of the project. The project documents remained secret for nearly 45 years, and despite Reiffel's revelations, the United States government has never officially recognized its involvement in the study.

🔗 Human rights 🔗 Medicine 🔗 History of Science 🔗 Alabama 🔗 Science Policy 🔗 Nursing

The Tuskegee Study of Untreated Syphilis in the Negro Male (informally referred to as the Tuskegee Experiment or Tuskegee Syphilis Study) was a study conducted between 1932 and 1972 by the United States Public Health Service (PHS) and the Centers for Disease Control and Prevention (CDC) on a group of nearly 400 African American men with syphilis. The purpose of the study was to observe the effects of the disease when untreated, though by the end of the study medical advancements meant it was entirely treatable. The men were not informed of the nature of the experiment, and more than 100 died as a result.

The Public Health Service started the study in 1932 in collaboration with Tuskegee University (then the Tuskegee Institute), a historically Black college in Alabama. In the study, investigators enrolled a total of 600 impoverished African-American sharecroppers from Macon County, Alabama. Of these men, 399 had latent syphilis, with a control group of 201 men who were not infected. As an incentive for participation in the study, the men were promised free medical care. While the men were provided with both medical and mental care that they otherwise would not have received, they were deceived by the PHS, who never informed them of their syphilis diagnosis and provided disguised placebos, ineffective methods, and diagnostic procedures as treatment for "bad blood".

The men were initially told that the experiment was only going to last six months, but it was extended to 40 years. After funding for treatment was lost, the study was continued without informing the men that they would never be treated. None of the infected men were treated with penicillin despite the fact that, by 1947, the antibiotic was widely available and had become the standard treatment for syphilis.

The study continued, under numerous Public Health Service supervisors, until 1972, when a leak to the press resulted in its termination on November 16 of that year. By then, 28 patients had died directly from syphilis, 100 died from complications related to syphilis, 40 of the patients' wives were infected with syphilis, and 19 children were born with congenital syphilis.

The 40-year Tuskegee Study was a major violation of ethical standards and has been cited as "arguably the most infamous biomedical research study in U.S. history." Its revelation led to the 1979 Belmont Report and to the establishment of the Office for Human Research Protections (OHRP) and federal laws and regulations requiring institutional review boards for the protection of human subjects in studies. The OHRP manages this responsibility within the United States Department of Health and Human Services (HHS). Its revelation has also been an important cause of distrust in medical science and the US government amongst African Americans.

On May 16, 1997, President Bill Clinton formally apologized on behalf of the United States to victims of the study, calling it shameful and racist. "What was done cannot be undone, but we can end the silence," he said. "We can stop turning our heads away. We can look at you in the eye, and finally say, on behalf of the American people, what the United States government did was shameful and I am sorry."

🔗 Songs

"Hitler Has Only Got One Ball", sometimes known as "The River Kwai March", is a World War II British song, the lyrics of which, sung to the tune of the World War I-era "Colonel Bogey March", impugn the masculinity of Nazi leaders by alleging they had missing, deformed, or undersized testicles. Multiple variant lyrics exist, but the most common version refers to rumours that Adolf Hitler had monorchism ("one ball"), and accuses Hermann Göring and Heinrich Himmler of microorchidism ("two but very small") and Joseph Goebbels of anorchia ("no balls at all"). An alternative version suggests Hitler's missing testicle is displayed as a war trophy in the Royal Albert Hall.

The author of the lyrics is unknown, though several claims have been made. The song first appeared among British soldiers in 1939 and was quickly taken up by Allied military and civilians. Its familiarity increased after its use in a scene in the 1957 film The Bridge on the River Kwai. The song has been cited as an example of morally-correct disrespect that used political mockery to boost morale in wartime.

🔗 Technology 🔗 Electronics 🔗 Electrical engineering

A ferrite bead (also known as a ferrite block, ferrite core, ferrite ring, EMI filter, or ferrite choke) is a type of choke that suppresses high-frequency electronic noise in electronic circuits.

Ferrite beads employ high-frequency current dissipation in a ferrite ceramic to build high-frequency noise suppression devices.

🔗 Biography 🔗 Aviation 🔗 Aviation/Aviation accident 🔗 Women's History 🔗 Libraries 🔗 Peru 🔗 Animals

Juliane Koepcke (born 1954), also known by her married name Juliane Diller, is a German Peruvian mammalogist. As a teenager in 1971, Koepcke was the lone survivor of the LANSA Flight 508 plane crash, then survived eleven days alone in the Amazon rainforest.