Thursday, June 23, 2011

NASA’s Cassini–Huygens spacecraft has discovered evidence for a large-scale saltwater reservoir beneath the icy crust of Saturn’s moon Enceladus. The data came from the spacecraft’s direct analysis of salt-rich ice grains close to the jets ejected from the moon. The study has been published in this week’s edition of the journal Nature.

Data from Cassini’s cosmic dust analyzer show the grains expelled from fissures, known as tiger stripes, are relatively small and usually low in salt far away from the moon. Closer to the moon’s surface, Cassini found that relatively large grains rich with sodium and potassium dominate the plumes. The salt-rich particles have an “ocean-like” composition and indicate that most, if not all, of the expelled ice and water vapor comes from the evaporation of liquid salt-water. When water freezes, the salt is squeezed out, leaving pure water ice behind.

Cassini’s ultraviolet imaging spectrograph also recently obtained complementary results that support the presence of a subsurface ocean. A team of Cassini researchers led by Candice Hansen of the Planetary Science Institute in Tucson, Arizona, measured gas shooting out of distinct jets originating in the moon’s south polar region at five to eight times the speed of sound, several times faster than previously measured. These observations of distinct jets, from a 2010 flyby, are consistent with results showing a difference in composition of ice grains close to the moon’s surface and those that made it out to the E ring, the outermost ring that gets its material primarily from Enceladean jets. If the plumes emanated from ice, they should have very little salt in them.

“There currently is no plausible way to produce a steady outflow of salt-rich grains from solid ice across all the tiger stripes other than salt water under Enceladus’s icy surface,” said Frank Postberg, a Cassini team scientist at the University of Heidelberg in Germany.

The data suggests a layer of water between the moon’s rocky core and its icy mantle, possibly as deep as about 50 miles (80 kilometers) beneath the surface. As this water washes against the rocks, it dissolves salt compounds and rises through fractures in the overlying ice to form reserves nearer the surface. If the outermost layer cracks open, the decrease in pressure from these reserves to space causes a plume to shoot out. Roughly 400 pounds (200 kilograms) of water vapor is lost every second in the plumes, with smaller amounts being lost as ice grains. The team calculates the water reserves must have large evaporating surfaces, or they would freeze easily and stop the plumes.

“We imagine that between the ice and the ice core there is an ocean of depth and this is somehow connected to the surface reservoir,” added Postberg.

The Cassini mission discovered Enceladus’ water-vapor and ice jets in 2005. In 2009, scientists working with the cosmic dust analyzer examined some sodium salts found in ice grains of Saturn’s E ring but the link to subsurface salt water was not definitive. The new paper analyzes three Enceladus flybys in 2008 and 2009 with the same instrument, focusing on the composition of freshly ejected plume grains. In 2008, Cassini discovered a high “density of volatile gases, water vapor, carbon dioxide and carbon monoxide, as well as organic materials, some 20 times denser than expected” in geysers erupting from the moon. The icy particles hit the detector target at speeds between 15,000 and 39,000 MPH (23,000 and 63,000 KPH), vaporizing instantly. Electrical fields inside the cosmic dust analyzer separated the various constituents of the impact cloud.

“Enceladus has got warmth, water and organic chemicals, some of the essential building blocks needed for life,” said Dennis Matson in 2008, Cassini project scientist at NASA’s Jet Propulsion Laboratory in Pasadena, California.

“This finding is a crucial new piece of evidence showing that environmental conditions favorable to the emergence of life can be sustained on icy bodies orbiting gas giant planets,” said Nicolas Altobelli, the European Space Agency’s project scientist for Cassini.

“If there is water in such an unexpected place, it leaves possibility for the rest of the universe,” said Postberg.

Sunday, May 23, 2021

A study by Public Health England (PHE), conducted between April 5 and May 16, found today the Pfizer- and AstraZeneca- made COVID-19 vaccines are effective against the B.1.617.2 variant of the coronavirus, first identified in India, offering a similar level of defence as against Lineage B.1.1.7, first identified in Kent, England.

Two doses of the Pfizer vaccine was, two weeks later, 88% effective in stopping symptomatic disease arising from the India variant and 93% against the Kent variant. Two doses of the AstraZeneca jab was 60% effective against the India variant and 66% against the Kent variant. However, after one dose of either, both vaccines were 33% effective against the India variant, compared to 50% against the Kent variant. PHE expects even higher rates of efficacy relating to hospital admissions and deaths, and both Sky News and The Guardian have indicated there is data suggesting it takes a longer time for the AstraZeneca jab to reach peak effectiveness.

The study’s analysis included 12,675 genomic-sequenced cases from all age groups and of several ethnicities: 11,621 of the Kent variant and 1,054 of the India variant. Head of immunisation at PHE Dr Mary Ramsay said the findings “[provide] reassurance that two doses of either vaccine offer high levels of protection against symptomatic disease from the B.1.617.2 variant”. The study said the “[n]umbers of cases and follow-up periods are currently insufficient to estimate effectiveness against severe disease, including hospitalisation and mortality”. It has nonetheless concluded that, while there was “an absolute reduction of one dose vaccine effectiveness against symptomatic disease with the B.1.617.2 variant of approximately 20% when compared to the B.1.1.7 variant”, “reductions in vaccine effectiveness after two doses were very small.”

PHE has said the difference in efficacy figures between the second dose of vaccines could be due to the slower rollout of the AstraZeneca jab, which was approved for use in the UK nearly a month after the Pfizer one.

The study, which is not peer-reviewed, comes ahead of UK Prime Minister Boris Johnson’s plan to ease COVID-19 lockdown restrictions in England by June 21. Johnson indicated May 14 the India variant “could pose a serious disruption to our progress”. Strategic COVID-19 response director at PHE Dr Susan Hopkins said “[w]e have now got early evidence that the vaccine protects” against the India variant, but that it was “too early to say” whether the reopening plans would be disrupted. She also said the trend indicated by the data was “quite clear”, and in the “right direction”.

The study’s lead author and consultant medical epidemiologist at PHE Dr Jamie Lopez Bernal says there is more confidence in data relating to the first dose than that from the second because “[t]here are bigger numbers that have been vaccinated with one dose.” He concluded “we classify that as moderate certainty around the first dose, but low levels of confidence around the second dose.”

Health Secretary of the United Kingdom Matt Hancock was encouraged by the findings, saying, according to a government press release, “[w]e can now be confident that over 20 million people – more than one in three – have significant protection against this new variant” against the India variant, and calling the study’s findings “groundbreaking”. He went on to encourage everyone, according to The Guardian, to get the jab.

Official government data says over 37 million Britons have received their first dose of a COVID-19 vaccine, and over 22 million their second, crossing a milestone of over 50 million doses. Another study from the PHE has said immunisations have prevented, from up to May 9, 13 thousand deaths and 39,100 hospital admissions among older people in England.

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Sunday, October 28, 2007

Bayern Munich remained undefeated in all competitions after a 0-0 draw against Borussia Dortmund. The draw leaves Bayern at the top of the table with 27 points. However, the lead is down to four points after Hamburg’s 1-0 win against Duisburg.

Franck Ribery didn’t pass a late fitness test and didn’t make the 18-man strong matchday squad. Luca Toni, Martin Demichelis an Jose Ernesto Sosa replaced Lukas Podolski, Philipp Lahm and Hamit Altintop. Jose Ernesto Sosa returned after being sidelined for almost two months after ankle surgery.

Bayern Munich and Borussia Dortmund exchanged plenty of chances and almost had a 50/50 possession between them.

Bayern Munich plays Borussia Mönchengladbach at home in the DFB Cup while Borussia Dortmund plays Eintracht Frankfurt in the same competition.

Thursday, November 8, 2007

What you are about to read is an American life as lived by renowned author Edmund White. His life has been a crossroads, the fulcrum of high-brow Classicism and low-brow Brett Easton Ellisism. It is not for the faint. He has been the toast of the literary elite in New York, London and Paris, befriending artistic luminaries such as Salman Rushdie and Sir Ian McKellen while writing about a family where he was jealous his sister was having sex with his father as he fought off his mother’s amorous pursuit.

The fact is, Edmund White exists. His life exists. To the casual reader, they may find it disquieting that someone like his father existed in 1950’s America and that White’s work is the progeny of his intimate effort to understand his own experience.

Wikinews reporter David Shankbone understood that an interview with Edmund White, who is professor of creative writing at Princeton University, who wrote the seminal biography of Jean Genet, and who no longer can keep track of how many sex partners he has encountered, meant nothing would be off limits. Nothing was. Late in the interview they were joined by his partner Michael Caroll, who discussed White’s enduring feud with influential writer and activist Larry Kramer.