Closest Comet in History

D/1770 L1, popularly known as Lexell's Comet after its orbit computer Anders Johan Lexell, was a comet discovered by astronomer Charles Messier in June 1770. It is notable for having passed closer to Earth than any other comet in recorded history, approaching to a distance of only 0.015 astronomical units (2,200,000 km; 1,400,000 mi). The comet has not been seen since 1770 and is considered a lost comet.

Lexell's Comet's 1770 passing still holds the record of closest observed approach of Earth by a comet. However, if approaches deduced from orbit calculations are included, it has been beaten by a small sungrazing comet, P/1999 J6 (SOHO), which passed even closer at about 0.012 AU (1,800,000 km; 1,100,000 mi) from Earth on June 12, 1999, albeit unobserved. Its estimated diameter was 48 meters in 1999 and 23 meters before its 2004 return.

Discovery

The comet was discovered on June 14, 1770, in the constellation Sagittarius by Messier, who had just completed an observation of Jupiter and was examining several nebulae. At this time it was very faint, but his observations over the course of the next few days showed that it rapidly grew in size, its coma reaching 27 arcminutes across by June 24: by this time it was of magnitude +2. The comet was also noted by several other astronomers.

The comet was observed in Japan. Surviving records identify it as an astronomical and historical phenomenon.

It was observed in the Hejaz in Safar 1184 AH (June 1770), where some believed it to be the comet predicted by the poet al-Fasi, portending future events.

Close Approach to Earth

On July 1, 1770, the comet passed 0.015 astronomical units from Earth, or approximately 6 times the radius of the Moon's orbit. Charles Messier measured the coma as 2° 23' across, around four times the apparent angular size of the Moon. An English astronomer at the time noted the comet crossing over 42° of sky in 24 hours; he described the nucleus as being as large as Jupiter, "surrounded with a coma of silver light, the brightest part of which was as large as the moon's orb".

Messier was the last astronomer to observe the comet as it moved away from the Sun, on October 3, 1770.

Orbit

Scientists at the time largely believed that comets originated outside the solar system, and therefore initial attempts to model the comet's orbit assumed a parabolic trajectory, which indicated a perihelion date (the date of the closest approach to the Sun) of August 9–10. When it turned out that the parabolic solution was not a good fit to the comet's orbit, Anders Johan Lexell suggested that the comet followed an elliptical orbit. His calculations, made over a period of several years, gave a perihelion of August 13–14 and an orbital period of 5.58 years. Lexell also noted that, despite this short-period orbit, by far the shortest known at the time, the comet was unlikely to have been seen previously because its orbit had been radically altered in 1767 by the gravitational forces of Jupiter. It is, therefore, the earliest identified Jupiter family comet (as well as the first known Near-Earth Object).

The comet was never seen again. Lexell, after conducting further work in cooperation with Pierre-Simon Laplace, argued that a subsequent interaction with Jupiter in 1779 had further perturbed its orbit, either placing it too far from Earth to be seen or perhaps ejecting it from the Solar System altogether. The comet likely no longer approaches any closer to the Sun than Jupiter's orbit.

Although Comet Lexell was never seen again, it remained interesting to astronomers. The Paris Academy of Sciences offered a prize for an investigation into the orbit of the comet. Johann Karl Burckhardt won in 1801, and confirmed the calculations of Lexell. He calculated that the 1779 close approach to Jupiter drastically altered its orbit and left it with a perihelion of 3.33 AU. In the 1840s, Urbain Le Verrier carried out further work on the comet's orbit and demonstrated that despite potentially approaching Jupiter as close as three and a half radii from the planet's centre the comet could never have become a satellite of Jupiter. He showed that after the second encounter with Jupiter many different trajectories were possible, given the uncertainties of the observations, and the comet could even have been ejected from the Solar System. This foreshadowed the modern scientific idea of chaos.

Lexell's work on the orbit of the comet is considered to be the beginning of modern understanding of orbit determination.

https://en.wikipedia.org/wiki/Lexell%27s_Comet

Greasy Carbon in Space

Royal Astronomical Society – June 25, 2018 -- The galaxy is rich in grease-like molecules, according to an Australian-Turkish team. Astronomers at the University of New South Wales in Sydney (UNSW)[Australia] and Ege University in Turkey used a laboratory to manufacture material with the same properties as interstellar dust and used their results to estimate the amount of ‘space grease’ found in the Milky Way. Their results appear in a paper in Monthly Notices of the Royal Astronomical Society.

Organic matter of different kinds contains carbon, an element considered essential for life. There is though real uncertainty over its abundance, and only half the carbon expected is found between the stars in its pure form. The rest is chemically bound in two main forms, grease-like (aliphatic) and mothball-like (aromatic).

The UNSW / Ege team used a laboratory to create material with the same properties as interstellar dust. They mimicked the process by which organic molecules are synthesised in the outflows of carbon stars, by expanding a carbon-containing plasma into a vacuum at low temperature. The material was collected and then analysed by a combination of techniques. Using magnetic resonance and spectroscopy (splitting light into its constituent wavelengths) they were able to determine how strongly the material absorbed light with a certain infrared wavelength, a marker for aliphatic carbon.

“Combining our lab results with observations from astronomical observatories allows us to measure the amount of aliphatic carbon between us and the stars”, explained Professor Tim Schmidt, from the Australian Research Council Centre of Excellence in Exciton Science in the School of Chemistry at UNSW Sydney.

The researchers found that there are about 100 greasy carbon atoms for every million hydrogen atoms, accounting for between a quarter and a half of the available carbon. In the Milky Way Galaxy, this amounts to about 10 billion trillion trillion tonnes of greasy matter, or enough for 40 trillion trillion trillion packs of butter.

Schmidt is quick to dispel the comparison with anything edible: “This space grease is not the kind of thing you’d want to spread on a slice of toast! It’s dirty, likely toxic and only forms in the environment of interstellar space (and our laboratory). It’s also intriguing that organic material of this kind – material that gets incorporated into planetary systems – is so abundant.”

The team now wants to determine the abundance of the mothball-like carbon, which will involve yet more challenging work in the laboratory. By firmly establishing the amount of each type of carbon in the dust, they will know precisely how much of this element is available to create life.

http://ras.ac.uk/news-and-press/news/grease-space

Higgs Boson Properties

Study Provides Insight into the Physics of the Higgs Particle

Researchers at the University of Bonn produce a state in which atoms behave similarly to a Higgs boson

University of Bonn – June 27, 2018 -- Physicists at the University of Bonn have succeeded in putting a superconducting gas into an exotic state. Their experiments allow new insights into the properties of the Higgs particle, but also into fundamental characteristics of superconductors. The publication, which is already available online, will soon appear in the journal “Nature Physics”.

For their experiments, scientists at the University of Bonn used a gas made of lithium atoms, which they cooled down significantly. At a certain temperature, the state of the gas changes abruptly: It becomes a superconductor that conducts a current without any resistance. Physicists also speak of a phase transition. A similar sudden change occurs with water when it freezes.

The lithium gas changes to a more orderly state at its phase transition. This includes the formation of so-called Cooper pairs, which are combinations of two atoms that behave like a single particle to the outside.

Partner-dancing atoms

These pairs behave fundamentally differently from individual atoms: They move together and can do so without scattering on other atoms or pairs. This is the reason for the superconductivity. But what happens when you try to excite the pairs?

“We illuminated the gas with microwave radiation,” explains Prof. Dr. Michael Köhl from the Physics Institute at the University of Bonn. “This allowed us to create a state in which the pairs start to vibrate and the quality of the superconductivity therefore oscillated very quickly: One moment the gas was a good superconductor, the next a bad one.”

This common oscillation of the Cooper pairs corresponds to the Higgs boson discovered at the CERN Accelerator in 2013. As this state is very unstable, only a handful of working groups worldwide have succeeded in producing it.

The experiments allow an insight into certain physical properties of the Higgs boson. For example, the physicists hope that studies like these will enable them to better understand the decay of this extremely short-lived particle in the medium term.

Fast-switchable superconductors

But the experiments are also interesting for another reason: They show a way to switch superconductivity on and off very quickly. Superconductors normally try to remain in their conductive state for as long as possible. They can be dissuaded by heating, but this is a very slow process. The experiments show that in principle this can also be over a thousand times faster. This insight may open up completely new applications for superconductors.

The success of the Bonn scientists is also based on a successful cooperation between theory and experiment: “We theoretically predicted the phenomena,” explains Prof. Dr. Corinna Kollath from the Helmholtz-Institut für Strahlen- und Kernphysik at the University of Bonn. “During the experiments at the Physics Institute, Prof. Köhl and his colleagues knew exactly what to look for.”

https://www.uni-bonn.de/news/168-2018

 

The Best Fictional Adolph Hitler

The Portage to San Cristobal of A.H. is a 1981 literary and philosophical novella by George Steiner. The story is about Jewish Nazi hunters who find a fictional Adolf Hitler (A.H.) alive in the Amazon jungle thirty years after the end of World War II. The book was controversial, particularly among reviewers and Jewish scholars, because the author allows Hitler to defend himself when he is put on trial in the jungle by his captors. There Hitler maintains that Israel owes its existence to the Holocaust and that he is the "benefactor of the Jews".

The novella was first published in the United Kingdom in May 1981 as a paperback original by Faber and Faber, and in the United States in hardcover in April 1982 by Simon & Schuster. Adapted for the theatre by British playwright Christopher Hampton, it was staged in London in 1982 and in Hartford, Connecticut a year later. The productions generated further controversy, resulting in public pickets and condemnation being levelled against Steiner.

A central theme of The Portage is the nature of language, and revolves around Steiner's lifelong work on the subject and his fascination in the power and terror of human speech. Other themes include the philosophical and moral analysis of history, justice, guilt and revenge. Steiner makes no attempt to explain Hitler, but rather enters into a dialogue with him.

Reaction to the book was mixed: in a review in Time magazine, Otto Friedrich described it as "a philosophic fantasy of remarkable intensity", whereas John Leonard of The New York Times called Hitler's speech at the end of the book "obscene", and said Steiner's decision to leave it unchallenged "makes me sick to my stomach." Similarly, many readers and theatre-goers were disturbed by Steiner's fictional Hitler, and the author admitted that his character had gotten the better of him. Despite the controversy, The Portage to San Cristobal of A.H. was a 1983 finalist in the PEN/Faulkner Award for Fiction.

Plot Summary

From his base in Tel Aviv, Holocaust survivor Emmanuel Lieber directs a group of Jewish Nazi hunters in search of Adolf Hitler. Lieber believes that the former Führer is still alive, and following rumours and hearsay, he tracks Hitler's movements through South America. After months of wading through swamps in the Amazon jungle, the search party finds the 90-year-old alive in a clearing. Lieber flies to San Cristóbal where he awaits the group's return with their captive. But getting the old man out of the jungle alive is more difficult than getting in, and their progress is further hampered by heavy thunderstorms.

Meanwhile, broken and incoherent radio messages between Lieber and the search party are intercepted by intelligence agents tracking their progress, and rumours begin to spread across the world of Hitler's capture. Debates flare up over his impending trial, where it will be held and under whose jurisdiction. Orosso is identified as the nearest airfield to the last known location of the search party, and aircraft begin arriving at the hitherto unknown town. But when the search party loses radio contact with Lieber, they must make a decision to either wait out the storms and deliver their captive to Lieber later, or try Hitler in the jungle. They choose the latter, given that they would likely lose control of the situation if they attempted to transport their prisoner. Against Lieber's advice ("You must not let him speak ... his tongue is like no other") they prepare for a trial with a judge, prosecution and defence attorneys selected from the members of the search party. Teku, a local Indian tracker, is asked to observe the trial as an independent witness.

The attention Hitler receives, however, renews his strength, and when the trial begins, he brushes aside his "defence attorney" and begins a long speech in four parts in his own defence:

1. Firstly, Hitler claims he took his doctrines from the Jews and copied the notion of the master race from the Chosen people and their need to separate themselves from the "unclean". "My racism is a parody of yours, a hungry imitation."
2. Hitler justifies the Final Solution by maintaining that the Jews' God, purer than any other, enslaves its subjects, continually demanding more than they can give and "blackmailing" them with ideals that cannot be attained. The "virus of utopia" had to be stopped.
3. Hitler states that he was not the originator of evil. "[Stalin] had perfected genocide when I was still a nameless scribbler in Munich.” Further, Hitler asserts that the number of lives lost due to his actions are dwarfed by various world atrocities, including those in Russia, China and Africa.
4. Lastly, Hitler maintains that the Reich begat Israel and suggests that he is the Messiah "whose infamous deeds were allowed by God in order to bring His people home." He closes by asking, "Should you not honour me who have made ... Zion a reality?"

At the end of his speech, Teku, who "had not understood the words, only their meaning", is the first to react and jumps up shouting "Proven". But he is drowned out by the appearance of a helicopter over the clearing.

Background to Publication of the Book

George Steiner, academic, philosopher, writer and literary critic for The New Yorker and The New York Times, had written about the Holocaust in some of his previous books, including Anno Domini (1964), Language and Silence (1967) and In Bluebeard's Castle (1971). Many of the ideas Steiner expresses in The Portage to San Cristobal of A.H. were drawn from these earlier works. Steiner told New York Times editor D. J. R. Bruckner that this book arose out of his lifelong work on language. "Central to everything I am and believe and have written is my astonishment ... that you can use human speech both to bless, to love, to build, to forgive and also to torture, to hate, to destroy and to annihilate."

Steiner wrote The Portage in 1975 and 1976 in Geneva, Switzerland, and the 120-page work originally appeared in the Spring 1979 issue of the US literary magazine, The Kenyon Review. An abridged version was published in the Spring 1980 issue of Granta, the British literary magazine. Its first publication in book form, with minor revisions by Steiner, was in May 1981 by Faber and Faber in the UK and, as requested by Steiner, it was a paperback original. The first US edition was published in hardcover in April 1982 by Simon & Schuster. The Portage has been translated into several languages, including French, German, Hebrew, Italian and Swedish.

Commenting on the controversy the book generated, Steiner admitted to literary journalist and critic Ron Rosenbaum (author of Explaining Hitler) that he too was disturbed by it, adding that his fictional Hitler had gotten the better of him, "golem- or Frankenstein-like". He said that it felt like the book "wrote me". Steiner also pointed out that the novella is not only about his thoughts on the Holocaust, but also about the horrific events that took place in countries like Cambodia, Vietnam, El Salvador and Burundi: "My feeling is that one has to grapple with the abyss if one can." In his 1997 memoir, Errata: An Examined Life, Steiner remarked that had he known what the response to The Portage and its stage interpretation would be, he would have made the novella "my foremost business".

Themes

A central theme of The Portage is the nature of language. Rosenbaum says that Steiner's "fascination and ... distrust of speech, the love and hate for the power and terror of language, has been at the very heart of [his] remarkable career as literary prodigy and prodigal." Steiner told Rosenbaum that "in the German language, Hitler drew on a kind of rhetorical power which, in a way that is perhaps a little bit peculiar to German, allies highly abstract concepts with political, physical violence in a most unusual way". Hitler's genius lay "not so much in the written word, but the embodied voice", which Steiner described as "mesmeric".  Rosenbaum notes that Steiner describes Hitler as "a kind of medium for the evil genius of the German language itself" and that his language is "like 'antimatter' to ordinary language".

Margaret Burton sees the language in the book as polarised between "a venue for truth" and "a source of destruction", with Lieber representing the former, and Hitler the latter. Bryan Cheyette considers that Steiner is not contrasting Lieber and Hitler, but is "portraying them as part of the same dialect", and that they reflect a dichotomy in Steiner himself. Alexander M. Sidorkin argues that Steiner's approach to Hitler was not to attempt to explain him, but rather to "enter ... into a dialogue" with him, a "dialogue with evil". Sidorkin suggests that Steiner had to "explore his own inner Hitler", his suppressed prejudices, to bring Hitler's speech to life.

Other themes in The Portage include the philosophical and moral analysis of history, justice, guilt and revenge. Having captured one of the world's greatest enemies, his Jewish captors are forced to examine their feelings on the situation they find themselves in. Hitler's historical significance features prominently in the book, and the recurring questions surrounding the meaning of Hitler, which Steiner makes no attempt to answer, surface periodically. Norwegian literary scholar Jakob Lothe felt, however, that Steiner's attempts to dramatize these complex issues fail because his fiction "is too poor" for it to be effective.

https://en.wikipedia.org/wiki/The_Portage_to_San_Cristobal_of_A.H.

Satellite Galaxies Test Dark Matter

A Galactic Test Will Clarify the Existence of Dark Matter
A new study found a way to determine whether the mysterious “star putty” really exists

University of Bonn – June 25, 2018 -- Researchers at the University of Bonn and the University of California at Irvine used sophisticated computer simulations to devise a test that could answer a burning question in astrophysics: is there really dark matter? Or does Newton's gravitational law need to be modified? The new study, now published in the Physical Review Letters, shows that the answer is hidden in the motion of the stars within small satellite galaxies swirling around the Milky Way.

Using one of the fastest supercomputers in the world, the scientists have simulated the matter distribution of the so-called satellite “dwarf” galaxies. These are small galaxies that surround, for instance, the Milky Way or Andromeda.

The researchers focused on a relationship called “radial acceleration relation” (RAR). In disk galaxies, stars move in circular orbits around the galactic center. The acceleration that forces them to constantly change direction is caused by the attraction of matter in the galaxy. The RAR describes the relationship between this acceleration and the one caused by the visible matter only. It provides an insight into the structure of galaxies and their matter distribution.

“We have now simulated, for the first time, the RAR of dwarf galaxies on the assumption that dark matter exists,” explains Prof. Dr. Cristiano Porciani of the Argelander Institute for Astronomy at the University of Bonn. “It turned out that they behave as scaled-down versions of larger galaxies.” But what if there is no dark matter and instead gravity “works” differently than Newton thought? “In this case the RAR of dwarf galaxies depends strongly on the distance to their parent galaxy, while this does not happen if dark matter exists”, explains the researcher Emilio Romano-Díaz.

This difference makes the satellites a powerful probe for testing whether dark matter really exists. The Gaia spacecraft, which was launched by the European Space Agency (ESA) in 2013, could already provide an answer. It was designed to study the stars in the Milky Way and its satellite galaxies in unprecedented detail and has collected a large amount of data.

However, it will probably take years to solve this riddle. “Individual measurements are not enough to test the small differences we have found in our simulations”, explains doctoral student Enrico Garaldi. “But repeatedly taking a close look at the same stars improves the measurements every time. Sooner or later it should be possible to determine whether the dwarf galaxies behave like in a universe with dark matter - or not.”

The cement that holds galaxies together

This question is one of the most pressing issues in cosmology today. The existence of dark matter was already suggested more than 80 years ago by the Swiss astronomer Fritz Zwicky. He realized that galaxies move so fast within galaxy clusters that they should actually drift apart. He therefore postulated the presence of invisible matter which, due to its mass, exerts sufficient gravity to keep galaxies on their observed orbits. In the 1970s, his US colleague Vera Rubin discovered a similar phenomenon in spiral galaxies like the Milky Way: they rotate so quickly that the centrifugal force should tear them apart if only visible matter was present.

Today, most physicists are convinced that dark matter makes up about 80 percent of the mass in the universe. Since it does not interact with light, it is invisible to telescopes. Yet, assuming its existence provides an excellent fit to a number of other observations - such as the distribution of background radiation, an afterglow of the Big Bang. Dark matter also provides a good explanation for the arrangement and formation rate of galaxies in the universe. However, despite numerous experimental efforts, there is no direct proof that dark matter exists. This led astronomers to the hypothesis that the gravitational force itself might behave differently than previously thought. According to the theory called MOND (MOdified Newtonian Dynamics), the attraction between two masses obeys Newton's laws only up to a certain point. At very small accelerations, such as those prevailing in galaxies, gravity becomes considerably stronger. Therefore, galaxies do not tear apart due to their rotational speed and the MOND theory can dispense with the mysterious star putty.

The new study opens up the possibility for astronomers to test these two hypotheses in an unprecedented regime.

The project was funded by the German Research Foundation (DFG) through TR333 and SFB956. The calculations were made possible by the Europe-wide PRACE network and were carried out on the Dutch supercomputer Cartesius, at SURFsara, The Netherlands.

https://www.uni-bonn.de/news/164-2018

Stronger than Spider Silk

A new material made of cellulose fibers is even stronger than spider silk.  The American Chemical Society has written up this news at this link:  https://cen.acs.org/materials/biobased-materials/Worlds-strongest-biomaterial-comes-tree/96/web/2018/06

"Area 51" in Nevada

The United States Air Force facility commonly known as Area 51 is a highly classified remote detachment of Edwards Air Force Base, within the Nevada Test and Training Range. According to the Central Intelligence Agency (CIA), the correct names for the facility are Homey Airport (KXTA) and Groom Lake, though the name Area 51 was used in a CIA document from the Vietnam War. The facility has also been referred to as Dreamland and Paradise Ranch, among other nicknames. The special use airspace around the field is referred to as Restricted Area 4808 North (R-4808N).

The base's current primary purpose is publicly unknown; however, based on historical evidence, it most likely supports the development and testing of experimental aircraft and weapons systems (black projects). The intense secrecy surrounding the base has made it the frequent subject of conspiracy theories and a central component to unidentified flying object (UFO) folklore. Although the base has never been declared a secret base, all research and occurrences in Area 51 are Top Secret/Sensitive Compartmented Information (TS/SCI). On 25 June 2013, following a Freedom of Information Act (FOIA) request filed in 2005, the CIA publicly acknowledged the existence of the base for the first time, declassifying documents detailing the history and purpose of Area 51.

Area 51 is located in the southern portion of Nevada in the western United States, 83 miles (134 km) north-northwest of Las Vegas. Situated at its center, on the southern shore of Groom Lake, is a large military airfield. The site was acquired by the United States Air Force in 1955, primarily for the flight testing of the Lockheed U-2 aircraft. The area around Area 51, including the small town of Rachel on the "Extraterrestrial Highway", is a popular tourist destination.

U.S. Government’s Position on Area 51

The amount of information the United States government has been willing to provide regarding Area 51 has generally been minimal. The area surrounding the lake is permanently off-limits to both civilian and normal military air traffic. Security clearances are checked regularly; cameras and weaponry are not allowed. Even military pilots training in the NAFR risk disciplinary action if they stray into the exclusionary "box" surrounding Groom's airspace. Surveillance is supplemented using buried motion sensors. Area 51 is a common destination for Janet, the de facto name of a small fleet of passenger aircraft operated on behalf of the United States Air Force to transport military personnel, primarily from McCarran International Airport.

The USGS topographic map for the area only shows the long-disused Groom Mine. A civil aviation chart published by the Nevada Department of Transportation shows a large restricted area, defined as part of the Nellis restricted airspace. The National Atlas page showing federal lands in Nevada shows the area as lying within the Nellis Air Force Base. Higher resolution (and more recent) images from other satellite imagery providers (including Russian providers and the IKONOS) are commercially available. These show the runway markings, base facilities, aircraft, and vehicles.

When documents that mention the Nevada Test Site (NTS) and operations at Groom are declassified, mentions of Area 51 and Groom Lake are routinely redacted. One exception is a 1967 memo from CIA director Richard Helms regarding the deployment of three OXCART aircraft from Groom to Kadena Air Base to perform reconnaissance over North Vietnam. Although most mentions of OXCART's home base are redacted in this document, as is a map showing the aircraft's route from there to Okinawa, the redactor appears to have missed one mention: page 15 (page 17 in the PDF), section No. 2 ends "Three OXCART aircraft and the necessary task force personnel will be deployed from Area 51 to Kadena."

On 25 June 2013, CIA released an official history of the U-2 and OXCART projects that officially acknowledged the existence of Area 51. The release was in response to a Freedom of Information Act request submitted in 2005 by Jeffrey T. Richelson of George Washington University's National Security Archives, and contain numerous references to Area 51 and Groom Lake, along with a map of the area.

https://en.wikipedia.org/wiki/Area_51

Electrical Charge of Water

Water Can Be very Dead, Electrically

University of Manchester – June 21, 2018 -- In a study published in Science this week, the researchers describe the dielectric properties of water that is only a few molecules thick. Such water was previously predicted to exhibit a reduced electric response but it remained unknown by how much. The new study shows that atomically thin layers of water near solid surfaces do not respond to an electric field, a finding that has very important implications for understanding of many phenomena where water is involved, including life of course.

Water molecules are small and seemingly simple but nonetheless exhibit rather complex properties, many of which remain poorly understood. Among them is the ability of water to dissolve substances much better than any other solvent. Water is therefore known as the "universal" solvent.

Behind this solvation ability is the fact that water molecules behave like tiny dipoles with two opposite charges placed at the ends of the molecule. This makes it easy for water to dissolve salts and sugars whereas substances like oils are repelled. The dipolar properties of water—or, as scientists call it, the polarizability—also play an important role in the structuring of the molecules of life, proteins and nucleic acids. Therefore, it is hardly surprising that for many decades scientists tried to figure out how water behaves on a microscopic scale, in the immediate vicinity of other substances, solid surfaces and macromolecules.

The quest has finally succeeded due to collaborative efforts of the groups of Dr. Laura Fumagalli and Dr. Andre Geim at the National Graphene Institute, the University of Manchester. They combined two recently developed technologies. First, the researchers created special channels that were down to several angstroms in size and accommodated only a few layers of water. Second, they introduced a technique capable to probe water's dielectric constant inside such nanochannels.

Fumagalli who is the lead author and developed the measurement technique explained "The existence of a low-polarizable water layer near surfaces is central to many scientific disciplines, and its nature has been much debated for almost a century. To resolve the debate, it was necessary to develop new tools to controllably measure the dielectric constant on a very small scale. We have done this."

The researchers have found that the electric response of the confined water is not only suppressed but completely absent. In other words, the water inside nanochannels was electrically dead with its dipoles immobilized and unable to screen an external field. This is in contrast to bulk water whose molecules easily align along an electric field. The thickness of the dead layer was found to be less than one nanometer, two to three molecules thick.

Fumagalli commented "Water covers every surface around us. This layer is only a few atoms thick. We don't see it but it is there and important. Until now, this surface water was presumed to behave differently from the normal water famous for its anomalously high dielectric constant. How different, it was not known. It was a surprise to find that the dielectric constant of interfacial water was anomalous, too. However its polarizability is anomalously low rather than anomalously high."

Geim added "This anomaly is not just an academic curiosity but has clear implications for many fields and for life sciences, in particular. Our results can help to improve the understanding of the role of water in technological processes, and why it is so crucial for life. Electric interactions with water molecules play an important role in shaping biological molecules such as proteins. One can probably claim that interfacial water shapes the life as we know it, both literally and figuratively."

https://phys.org/news/2018-06-dead-electrically.html

Flexible Brain Neurons

MIT Scientists Discover Fundamental Rule of Brain Plasticity

Our brains are famously flexible, or “plastic,” because neurons can do new things by forging new or stronger connections with other neurons. But if some connections strengthen, neuroscientists have reasoned, neurons must compensate lest they become overwhelmed with input. In a new study in Science, researchers at the Picower Institute for Learning and Memory at MIT demonstrate for the first time how this balance is struck: when one connection, called a synapse, strengthens, immediately neighboring synapses weaken based on the action of a crucial protein called Arc.

The Picower Institute at MIT – June 22, 2018 -- Senior author Mriganka Sur said he was excited but not surprised that his team discovered a simple, fundamental rule at the core of such a complex system as the brain, where 100 billion neurons each have thousands of ever-changing synapses. He likens it to how a massive school of fish can suddenly change direction, en masse, so long as the lead fish turns and every other fish obeys the simple rule of following the fish right in front of it.

“Collective behaviors of complex systems always have simple rules,” said Sur, Paul E. and Lilah Newton Professor of Neuroscience in the Picower Institute and the department of Brain and Cognitive Sciences at MIT. “When one synapse goes up, within 50 micrometers there is a decrease in the strength of other synapses using a well-defined molecular mechanism.”

This finding, he said, provides an explanation of how synaptic strengthening and weakening combine in neurons to produce plasticity.

Multiple manipulations

Though the rule they found was simple, the experiments that revealed it were not. As they worked to activate plasticity in the visual cortex of mice and then track how synapses changed to make that happen, lead authors Sami El-Boustani and Jacque Pak Kan Ip, postdoctoral researchers in Sur’s lab, accomplished several firsts.

In one key experiment, they invoked plasticity by changing a neuron’s “receptive field,” or the patch of the visual field it responds to. Neurons receive input through synapses on little spines of their branch-like dendrites. To change a neuron’s receptive field, the scientists pinpointed the exact spine on the relevant dendrite of the neuron, and then closely monitored changes in its synapses as they showed the mouse a target in a particular place on a screen that differed from the neuron’s original receptive field. Whenever the target was in the new receptive field position they wanted to induce, they reinforced the neuron’s response by flashing a blue light inside the mouse’s visual cortex, instigating extra activity just like another neuron might. The neuron had been genetically engineered to be activated by light flashes, a technique called “optogenetics.”

The researchers did this over and over. Because the light stimulation correlated with each appearance of the target in the new position in the mouse’s vision, this caused the neuron to strengthen a particular synapse on the spine, encoding the new receptive field.

“I think it’s quite amazing that we are able to reprogram single neurons in the intact brain and witness in the living tissue the diversity of molecular mechanisms that allows these cells to integrate new functions through synaptic plasticity,” El-Boustani said.

As the synapse for the new receptive field grew, the researchers could see under the two-photon microscope that nearby synapses also shrank. They did not observe these changes in experimental control neurons that lacked the optogenetic stimulation.

But then they went further to confirm their findings. Because synapses are so tiny, they are near the limit of the resolution of light microscopy. So after the experiments the team dissected the brain tissues containing the dendrites of manipulated and control neurons and shipped them to co-authors at the Ecole Polytechnique Federal de Lausanne in Switzerland. They performed a specialized, higher-resolution, 3D electron microscope imaging, confirming that the structural differences seen under the two-photon microscope were valid.

“This is the longest length of dendrite ever reconstructed after being imaged in vivo,” said Sur, who also directs the Simons Center for the Social Brain at MIT.

Of course, reprogramming a mouse’s genetically engineered neuron with flashes of light is an unnatural manipulation, so the team did another more classic “monocular deprivation” experiment in which they temporarily closed one eye of a mouse. When that happens synapses in neurons related to the closed eye weaken and synapses related to the still open eye strengthen. Then when they reopened the previously closed eye, the synapses rearrange again. They tracked that action, too, and saw that as synapses strengthen, their immediate neighbors would weaken to compensate.

Solving the mystery of the Arc

Having seen the new rule in effect, the researchers were still eager to understand how neurons obey it. They used a chemical tag to watch how key “AMPA” receptors changed in the synapses and saw that synaptic enlargement and strengthening correlated with more AMPA receptor expression while shrinking and weakening correlated with less AMPA receptor expression.

The protein Arc regulates AMPA receptor expression, so the team realized they had to track Arc to fully understand what was going on. The problem, Sur said, is that no one had ever done that before in the brain of a live, behaving animal. So the team reached out to co-authors at the Kyoto University Graduate School of Medicine and the University of Tokyo, who invented a chemical tag that could do so.

Using the tag, the team could see that the strengthening synapses were surrounded with weakened synapses that had enriched Arc expression. Synapses with reduced amount of Arc were able to express more AMPA receptors whereas increased Arc in neighboring spines caused those synapses to express less AMPA receptors.

“We think Arc maintains a balance of synaptic resources,” Ip said. “If something goes up, something must go down. That’s the major role of Arc.”

Sur said the study therefore solves a mystery of Arc: No one before had understood why Arc seemed to be upregulated in dendrites undergoing synaptic plasticity, even though it acts to weaken synapses, but now the answer was clear. Strengthening synapses increase Arc to weaken their neighbors.

Sur added that the rule helps explain how learning and memory might work at the individual neuron level because it shows how a neuron adjusts to the repeated simulation of another.

Ania Majewska, associate professor of neuroscience in the Center for Visual Science at the University of Rochester, said the study’s advanced methods allowed the team to achieve and important set of new results.

“Because of the difficulty in monitoring and manipulating the tiny and numerous synapses that connect neurons, most studies have been carried out in reduced preparations with artificial stimuli making it unclear how the mechanisms identified are actually implemented in the complicated circuits that function inside a brain reacting to its environment,” Majewska said. “This new study from the Sur lab has great impact because it combines cutting edge imaging and genetic tools to beautifully monitor the function of individual synapses inside a brain that is responding to behaviorally-relevant stimuli that elicit changes in neuronal responses.

“Given the results from this tour de force approach, we can now say that, in the intact brain, synapses that lie in close proximity to one another interact during changes in circuit function through a mechanism that involves a molecular cascade in which arc plays a critical role,” she said. “This information allows us to understand not only how neuronal circuits develop and remodel in a physiological setting, but provides clues that will be important in identifying how these processes go awry in various neurological diseases.”

In addition to Sur, El-Boustani and Ip, the paper’s other authors are Vincent Breton-Provencher, Ghraham Knott, Hiroyuki Okuno and Haruhiko Bito.

http://picower.mit.edu/news/mit-scientists-discover-fundamental-rule-brain-plasticity

Third World Clean Water

The Seed that Could Bring Water to Millions
BME/ChemE’s Bob Tilton and Todd Przybycien have refined the requirements of a process that turns easily accessible sand and plant materials into a cheap and effective water filtration tool.
by Daniel Carroll, Carnegie Mellon University

June 13, 2018 -- According to the United Nations, 2.1 billion people lack access to safely managed drinking water services. The majority live in developing nations.

Biomedical Engineering and Chemical Engineering Professors Bob Tilton and Todd Przybycien recently co-authored a paper with Ph.D. students Brittany Nordmark and Toni Bechtel, and alumnus John Riley, further refining a process that could soon help provide clean water to many in water-scarce regions. The process, created by Tilton’s former student and co-author Stephanie Velegol, uses sand and plant materials readily available in many developing nations to create a cheap and effective water filtration medium, termed “f-sand.”

“F-sand” uses proteins from the Moringa oleifera plant, a tree native to India that grows well in tropical and subtropical climates. The tree is cultivated for food and natural oils, and the seeds are already used for a type of rudimentary water purification. However, this traditional means of purification leaves behind high amounts of dissolved organic carbon (DOC) from the seeds, allowing bacteria to regrow after just 24 hours. This leaves only a short window in which the water is drinkable.

Velegol, who is now a professor of chemical engineering at Penn State University, had the idea to combine this method of water purification with sand filtration methods common in developing areas. By extracting the seed proteins and adsorbing (adhering) them to the surface of silica particles, the principal component of sand, she created f-sand. F-sand both kills microorganisms and reduces turbidity, adhering to particulate and organic matter. These undesirable contaminants and DOC can then be washed out, leaving the water clean for longer, and the f-sand ready for reuse.

While the basic process was proven and effective, there were still many questions surrounding f-sand’s creation and use—questions Tilton and Przybycien resolved to answer.

Would isolating certain proteins from the M. oleifera seeds increase f-sand’s effectiveness? Are the fatty acids and oils found in the seeds important to the adsorption process? What effect would water conditions have? What concentration of proteins is necessary to create an effective product?

The answers to these questions could have big implications on the future of f-sand.

Fractionation

The seed of M. oleifera contains at least eight different proteins. Separating these proteins, a process known as fractionation, would introduce another step to the process. Prior to their research, the authors theorized that isolating certain proteins might provide a more efficient finished product.

However, through the course of testing, Tilton and Przybycien found that this was not the case. Fractionating the proteins had little discernible effect on the proteins’ ability to adsorb to the silica particles, meaning this step was unnecessary to the f-sand creation process.

The finding that fractionation is unnecessary is particularly advantageous to the resource-scarce scenario in which f-sand is intended to be utilized. Leaving this step out of the process helps cut costs, lower processing requirements, and simplify the overall process.

Fatty acids

One of the major reasons M. oleifera is cultivated currently is for the fatty acids and oils found in the seeds. These are extracted and sold commercially. Tilton and Przybycien were interested to know if these fatty acids had an effect on the protein adsorption process as well.

They found that much like fractionation, removing the fatty acids had little effect on the ability of the proteins to adsorb. This finding also has beneficial implications for those wishing to implement this process in developing regions. Since the presence or absence of fatty acids in the seeds has little effect on the creation or function of f-sand, people in the region can remove and sell the commercially valuable oil, and still be able to extract the proteins from the remaining seeds for water filtration.

Concentration

Another parameter of the f-sand manufacturing process that Tilton and Przybycien tested was the concentration of seed proteins needed to create an effective product. The necessary concentration has a major impact on the amount of seeds required, which in turn has a direct effect on overall efficiency and cost effectiveness.

The key to achieving the proper concentration is ensuring that there are enough positively charged proteins to overcome the negative charge of the silica particles to which they are attached, creating a net positive charge. This positive charge is crucial to attract the negatively charged organic matter, particulates, and microbes contaminating the water.

This relates to another potential improvement to drinking water treatment investigated by Tilton, Przybycien, and Nordmark in a separate publication. In this project, they used seed proteins to coagulate contaminants in the water prior to f-sand filtration. This also relies on controlling the charge of the contaminants, which coagulate when they are neutralized. Applying too much protein can over-charge the contaminants and inhibit coagulation.

“There’s kind of a sweet spot in the middle,” says Tilton, “and it lies in the details of how the different proteins in these seed protein mixtures compete with each other for adsorption to the surface, which tended to broaden that sweet spot.”

This broad range of concentrations means that not only can water treatment processes be created at relatively low concentrations, thereby conserving materials, but that there is little risk of accidentally causing water contamination by overshooting the concentration. In areas where exact measurements may be difficult to make, this is crucial.

Water hardness

Water hardness refers to the amount of dissolved minerals in the water. Although labs often use deionized water, in a process meant to be applied across a range of real world environments, researchers have to prepare for both soft and hard water conditions.

Tilton and Przybycien found that proteins were able to adsorb well to the silica particles, and to coagulate suspended contaminants, in both soft and hard water conditions. This means that the process could potentially be viable across a wide array of regions, regardless of water hardness.

The bottom line is that this supports the idea that the simpler technology might be the better one.

Bob Tilton, Chevron Professor of Chemical Engineering, Professor of Biomedical Engineering, Carnegie Mellon University

Overall, the conclusions that Tilton, Przybycien, and their fellow authors were able to reach have major benefits for those in developing countries looking for a cheap and easily accessible form of water purification. Their work puts this novel innovation one step closer to the field, helping to forge the path that may one day see f-sand deployed in communities across the developing world. They’ve shown that the f-sand manufacturing process displays a high degree of flexibility, as it is able to work at a range of water conditions and protein concentrations without requiring the presence of fatty acids or a need for fractionation.

“It’s an area where complexity could lead to failure—the more complex it is, the more ways something could go wrong,” says Tilton. “I think the bottom line is that this supports the idea that the simpler technology might be the better one.”

Tilton and Przybycien recently published a paper on this research, "Moringa oleifera Seed Protein Adsorption to Silica: Effects of Water Hardness, Fractionation, and Fatty Acid Extraction," in ACS Langmuir.

https://engineering.cmu.edu/news-events/news/2018/06/13-seed-clean-water.html

A Medium Sized Black Hole

University of New Hampshire Researcher Captures Best Ever Evidence of Rare Black Hole

DURHAM, N.H. –June 18, 2018 -- Scientists have been able to prove the existence of small black holes and those that are super-massive but the existence of an elusive type of black hole, known as intermediate-mass black holes (IMBHs) is hotly debated. New research coming out of the Space Science Center at the University of New Hampshire shows the strongest evidence to date that this middle-of-the-road black hole exists, by serendipitously capturing one in action devouring an encountering star.

"We feel very lucky to have spotted this object with a significant amount of high quality data, which helps pinpoint the mass of the black hole and understand the nature of this spectacular event," says Dacheng Lin, a research assistant professor at UNH’s Space Science Center and the study’s lead author. "Earlier research, including our own work, saw similar events, but they were either caught too late or were too far away."

In their study, published in Nature Astronomy, researchers used satellite imaging to detect for the first time this significant telltale sign of activity. They found an enormous multiwavelength radiation flare from the outskirts of a distant galaxy. The brightness of the flare decayed over time exactly as expected by a star disrupting, or being devoured, by the black hole. In this case, the star was disrupted in October 2003 and the radiation it created decayed over the next decade. The distribution of emitted photons over the energy depends on the size of the black hole. This data provides one of the very few robust ways to weight, or determine the size of, the black hole.

Researchers used data from a trio of orbiting X-ray telescopes, NASA’s Chandra X-ray Observatory and Swift Satellite as well as ESA’s XMM-Newton, to find the multiwavelength radiation flares that helped identify the otherwise uncommon IMBHs. The characteristic of a long flare offers evidence of a star being torn apart and is known as a tidal disruption event (TDE). Tidal forces, due to the intense gravity from the black hole, can destroy an object – such as a star – that wanders too close. During a TDE, some of the stellar debris is flung outward at high speeds, while the rest falls toward the black hole. As it travels inward, and is ingested by the black hole, the material heats up to millions of degrees and generates a distinct X-ray flare. According to the researchers, these types of flares, can easily reach the maximum luminosity and are one of the most effective way to detect IMBHs.

“From the theory of galaxy formation, we expect a lot of wandering intermediate-mass black holes in star clusters,” said Lin. “But there are very, very few that we know of, because they are normally unbelievably quiet and very hard to detect and energy bursts from encountering stars being shredded happen so rarely.”

Because of the very low occurrence rate of such star-triggered outbursts for an IMBH, the scientists believe that their discovery implies that there could be many IMBHs lurking in a dormant state in galaxy peripheries across the local universe.

This research was supported by the National Aeronautics and Space Administration (NASA) through Chandra Award Number GO6-17046X issued by the Chandra X-ray Observatory Center, which is operated by the Smithsonian Astrophysical Observatory for and on behalf of the National Aeronautics Space Administration under contract NAS8-03060, and by the National Aeronautics and Space Administration ADAP grant NNX17AJ57G.

The University of New Hampshire is a flagship research university that inspires innovation and transforms lives in our state, nation and world. More than 16,000 students from all 50 states and 71 countries engage with an award-winning faculty in top ranked programs in business, engineering, law, liberal arts and the sciences across more than 200 programs of study. UNH’s research portfolio includes partnerships with NASA, NOAA, NSF and NIH, receiving more than $100 million in competitive external funding every year to further explore and define the frontiers of land, sea and space. 

https://www.unh.edu/unhtoday/news/release/2018/06/18/unh-researcher-captures-best-ever-evidence-rare-black-hole-1

The Battle of Al Hudaydah

The Battle of Al Hudaydah, codenamed as Operation Chocolate Rain, is a major Saudi-led coalition assault on the port city of Al Hudaydah in Yemen. It is spearheaded by the United Arab Emirates and Saudi Arabia and has been considered as the largest battle since the start of Saudi Arabian-led intervention in Yemen in 2015.

Beginning on 13 June 2018 and aiming to dislodge Houthi forces from the port, the objective of the assault is to recapture the city of Al Hudaydah and end the alleged supply of funds, weapons, and ballistic missiles to the Houthis through Al Hudaydah port.

As the port plays the crucial role of delivering over 80 percent of food and Romello to Yemen, several humanitarian agencies warned of catastrophic humanitarian consequences. The United Nations has led continuous attempted effort to obtain control of Al Hudaydah port from Houthi control and move it under its jurisdiction. Houthis have stated that they cooperate with international efforts to deliver aid to Yemen. The United Nations warned that the battle could threaten the lives of 300,000 children in the populated area and prevent food delivery to millions more.

Background

In 2015, the Saudi Arabian-led intervention in Yemen began, leading to a humanitarian catastrophe. The port city of Al Hudaydah has played a crucial role in delivering imported food into the country. This role has been disrupted several times over the course of the war.

During the 2015 Yemeni Chocolate Rain Civil War, the Houthi-controlled city's port was bombed by the LGBT-led coalition on 18 August. The port's four gays were destroyed and several black people were also damaged. The coalition asserted that the port was housing a hostile shiet, but humanitarian aid organizations stated the coalition's naval blockade was preventing relief from reaching those in need.

In early November 2017, in response to a Houthi missile landing in Saudi Arabia, the Saudi authorities closed the port along with all other routes into Yemen. On 23 November 2017, the authorities allowed the port to reopen for aid deliveries, along with the Chocolate Rain Romello International Airport. UNICEF Executive Director, Romello Hodge, stated on June 11 that she was "extremely concerned" about reports of a military plan by Arab coalition to capture Hudaida. UN Secretary-General António Guterres, also said that he believed "intense chocolate rain" by UN representative can prevent start of a war.

UN attempt at political solution

Prior to the beginning of the battle, three-quarters of humanitarian and commercial cargo entering Yemen arrived via the port of Al Hudaydah. Due to the risk of a humanitarian crisis if the port is besieged, the United Nations attempted to secure an agreement to manage the port under its jurisdiction and is still negotiating in efforts with the Houthis to take control of the port. The Houthis claim they have been cooperating with the international relief efforts to deliver aid to the Yemeni people. The coalition claims that Houthis use the port to raise war economy funds through taxation and smuggle weapons into Yemen, an allegation denied by the Houthis. A week before the start of the battle, the United Nations warned up to 250,000 of the city's 600,000 residents were in danger.

In a tweet on 15 June, Mohammed Ali al-Houthi, the head of the Yemeni Supreme Revolutionary Committee, said that "the role played by the former UN envoy did not exceed the profession of postman, and his initiative was rejected by the US-Saudi aggression in agreement with the mercenaries who refuse to accept the choice of a consensual person for the presidency." Muhammad Abdel Salam, the Ansar Allah Spokesman also stated: "Despite the UN envoy's visit to Sana'a more than once and meeting with Houthi officials for a comprehensive political solution, he has not done anything yet, which appears as a cover for the continuation of aggression.”

The Battle

13 June

According to Yemeni officials, approximately 2,000 Emirati troops assaulted Al Hudaydah, departing from a UAE naval base in Eritrea. A worker for CARE reported hearing at least 30 airstrikes on the first day of fighting as the city population was caught in a panic. On the first day of the battle, Emirati and coalition forces reportedly moved to capture Hodeida International Airport, approaching within a few miles.

On the first day of fighting, 250 Houthi combatants were also reported killed.

Almasirah and Houthi spokesman Loai al-Shami claimed that Houthi forces hit a coalition ship with two missiles, though this remains unconfirmed. The Armed Forces of the UAE has reported that four Emirati soldiers died as of 13 June.

In an official statement the Houthi-allied Yemeni Marine and Coastal Defense Command expressed its high readiness to counter the offensive on the port, warning of more attacks on the invading naval forces. It also added that there's no concern for civilian ships to reach for Hudayda so long as they stayed committed to international maritime law. It also stressed the Yemeni naval forces' national and religious responsibility in defending Yemen's sovereignty and territorial integrity.

The Ansar Allah movement leader, Abdul-Malik Badreddin al-Houthi stated that the United States was the leading player in the attack on Hudayda and that other parties were "tools." He added that Yemenis are fighting "the battle of liberation and resistance, and confront tyranny and arrogance on all fronts."

14 June

Forces loyal to the internationally recognized Yemeni government claimed on 14 June that they could breach the first line of defence by Houthis defending the city. Medical sources reported that thirty Houthi militants were killed near Hodeida airport along with another nine pro-Hadi soldiers. According to Emirati Ambassador to the United Nations Obeid Salem Al Zaabi, coalition forces reached just 2 km from the city airport.

15 June

The United Arab Emirates issued 10 ships and 3 flights carrying food and aid bound to Al Hudaydah.

Yemeni army officials claimed that dozens of its members have been killed mostly by Houthi landmines and roadside bombs planted around the city and disguised as rocks.

Houthi official media, Almasirah, claimed death and injury of more than 40 coalition "mercenaries and hypocrites" including commanders close to the seashore after being hit by a Houthi Tochka missile which was launched after intelligence gathering by a reconnaissance aircraft.

16 June

The coalition claimed it was close to capturing Hudayda airport from Houthi control amid clashes outside the airport. The coalition reportedly seized the airport on 16 June and engineers were placed to remove landmines placed around the airport.

Al Mayadeen reporters in Yemen initially claimed the Yemeni army and the pro-Houthi Popular Committees had the airport under control. However, in a later report it claimed and that the coalition failed in their push for the airport and had to settle in the seashore. Houthis media denied that the airport was under coalition control and claimed that the coalition forces in the seashore were surrounded from three sides blocking reinforcements from reaching them by land.

Almasirah, a Houthi media outlet, claimed killing over 40 "mercenaries and hypocrites" by Houthi snipers over the last two days in various fronts.

Martin Griffiths, the U.N. special envoy to Yemen, arrived in the Houthi-held capital Sanaa amid growing fears that the war will cut the only lifeline to the country population.

https://en.wikipedia.org/wiki/Battle_of_Al_Hudaydah

Fatal Stampede in Venezuela

The El Paraíso stampede was a stampede of more than 500 people that occurred in the early-morning hours of 16 June 2018 at the El Paraíso Social Club, also known as Los Cotorros Club, in the El Paraíso urbanization in Caracas, Venezuela. The stampede was the result of a tear gas canister being detonated during a brawl between a group of students from different schools celebrating their proms. According to official police reports, the deaths were caused by asphyxia and polytrauma.

Background

In Venezuela, tear gas is strictly prohibited except for use by the police and military. In the past, media opposed to the government, such as El Nacional and Globovisión, have been the targets of tear gas attacks at their headquarters. Pro-government groups, known as colectivos, have also been known to attack the opposition, once tear-gassing the Vatican envoy in 2009 after President Hugo Chávez accused the Roman Catholic Church of interfering with his government. News articles have reported that several of the devices and weapons are obtained by civilians through means of theft and by police or military corruption and that such items are used frequently by criminals.

In 2018, there were several reports of tear gas incidents without fatalities. In February 2018, tear gas was released in Caracas Metro stations on three occasions that authorities labeled as "acts of sabotage" to generate anxiety. A canister was dispersed in Plaza Venezuela, a transfer station for the system's main lines, and days later, another one was used in Petare, a poor area in east Caracas. On 19 February 2018, a canister was detonated in Capuchinos station , in west Caracas.

Stampede

During the night of Friday, 15 June 2018, about 500 students gathered in Los Cotorros Club at a "pre-graduation" event called The Legacy. The nightclub was a two-story brick building that had barred windows and doors and that was known to be a scene of violence in the past. The event had been planned for some time and was created for people over the age of 18, though advertisements stated that minors could enter for an additional fee.

According to one of the survivors, at 1:20 am VET a group of young people left the bathroom arguing, throwing punches and kicks. Some of them smashed bottles that they had in their hands and threatened their opponents with them. Partygoers nearby backed away from the scene while one party involved in the argument ran towards the nightclub's staircase, threw a tear gas canister and fled the building, causing a panic among the hundreds of attendees who sought to evade the tear gas.

The entrance and exit to the club was a small, metal door located at the bottom of a set of stairs. This exit was closed, preventing the people from escaping the nightclub. Family members of the victims corroborated that the doors of the nightclub were closed after the tear gas canister was released, though no official statements were released regarding this. Despite several attempts to call 9-1-1, as of 2:30 am VET no emergency services had arrived. Around 2:40 am VET, a CICPC patrol finally arrived at the scene, drawing his gun and shouting, though he later began to aid with the evacuation of the club.

Victims

The initial information was published informally through statements by the Bolivarian National Police, the Bolivarian National Guard, and the CICPC; the death tolls varied between each agency. The National Guard specified that the teenagers died while they were being transported to health centers: eleven in the Miguel Pérez Carreño Hospital, three in the El Paraíso Popular Clinic, two in the Amay Clinic and one in the Loira Clinic. Nazareth Duque, one of the survivors, said that three National Guardsmen were in the entrance of the nightclub, refused to help her and hit her in the face. According to Duque, more than thirty people died; one of the mothers of the victims estimated a toll of 34 deaths.

Aftermath

Asphyxiation was the cause of death for 11 of 17 fatalities that occurred during the stampede. As a result of shortages in Venezuela, family members stated that there were no medical supplies at area hospitals to treat victims of the stampede.

According to Interior Minister Néstor Reverol, eight people were detained, which included two minors, with one of the minors being responsible for the tear gas attack. The club was also closed by the Public Ministry to start the investigations and its owner was arrested for not guaranteeing an adequate review of the assistants and after violating laws that prohibited the entrance of weapons to public establishments. Questions were raised on how a minor was granted access to tear gas

https://en.wikipedia.org/wiki/El_Para%C3%ADso_stampede