The agency said the finding supports its recommendation "that all eligible persons be offered COVID-19 vaccination, regardless of previous SARS-CoV-2 infection status."

Some US politicians, including Senator Rand Paul, have in the past said they do not plan to take a COVID-19 vaccine because of their natural immunity derived from prior infection.

The new study was based on 246 Kentucky adults who were reinfected in May and June this year after previously being infected in 2020.

They were compared with 492 "controls" who were matched by sex, age, and time of initial positive test.

The analysis found that unvaccinated people were 2.34 times as likely to be reinfected compared to people fully vaccinated with the Pfizer, Moderna or Johnson & Johnson vaccines.

The duration of infection-acquired immunity remains poorly understood and may be affected by the emergency of newer variants, the paper said.

For example, laboratory studies have shown that blood samples from people previously infected with the original Wuhan strain had poor antibody responses to the Beta variant first identified in South Africa.

One of the limitations of the study is it was conducted before Delta became the dominant strain in the United States.

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For instance, climate change could adversely impact the operation of critical energy systems and infrastructure, potentially disrupting the provision of electricity. While nuclear power plants (NPPs) could be a viable solution for generating low-carbon electricity, the operation of these plants is susceptible to climate change and to the extreme weather conditions resulting from it.

Ali Ahmad, a researcher at Harvard University, recently carried out a study investigating the possible effects of climate change on NPPs. His paper, published in Nature Energy, specifically assessed whether climatic changes over the past three decades impacted the frequency of nuclear power outages.

"With more than three decades of data on changing climate, we are now in a position to empirically assess the impact of climate change on power plant operations," Ahmad wrote in his paper. "Such empirical assessments can provide an additional measure of the resilience of power plants going forward. Here I analyze climate-linked outages in nuclear power plants over the past three decades."

Compared to other power plants, such as those based on fossil fuels and biomass, NPPs require stricter safety regulations. Moreover, after an unplanned outage, nuclear reactors need to undergo a series of tests and analyses aimed at identifying the issue, thus it can take a while before they are started again.

Understanding the extent to which climate change can impact the functioning of NPPs is thus of vital importance, as it could inspire the development of strategies to mitigate these climate-related effects. In his paper, Ahmad examined the frequency of climate-linked nuclear power outages over the past three decades or so.

Overall, he found that NPP outages caused by climatic events have become increasingly more frequent in the past few decades. Many of these outages were induced by changes in climate, while others were a result of natural disasters such as earthquakes or tsunamis. Ahmad screened available data to only focus on outages associated with climate change.

"My assessment shows that the average frequency of climate-induced disruptions has dramatically increased from 0.2 outage per reactor-year in the 1990s to 1.5 in the past decades," Ahmad wrote in his paper. "Based on the projections for adopted climate scenarios, the average annual energy loss of the global nuclear fleet is estimated to range between 0.8% and 1.4% in the mid-term (2046-2065) and 1.4% and 2.4% in the long term (2081-2100)."

As many researchers have been highlighting the value of nuclear power as a means to slow down and mitigate climate change, understanding the effects of climatic changes and global warming on NPPs before humans start heavily relying on them is of great importance. Ahmad's recent analyses demonstrate that the operation of NPPs was significantly disrupted by changes in climate over the past decades. In the future, the results of his study could help to create more realistic economic and nuclear energy models that take climate-associated risks into consideration.

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Here is the global state of play over the past week, according to a specialised AFP database.

Upsurge in North America

The pandemic is accelerating almost everwhere, most markedly in the US and Canada which saw a jump of 44 percent in average daily cases over the past week.

Cases increased by 20 percent in Oceania, 11 percent in the Middle East, six percent in Asia, three percent in Europe and one percent in Africa.

This week the only region that did not record an uptick in cases was Latin America and the Caribbean, which saw daily infections decline by 13 percent over the previous week.

Six percent up

The average number of new daily cases globally increased by six percent over the week to 612,000, according to an AFP tally to Thursday.

The pandemic has continued to gain ground since mid-June largely due to the highly contagious Delta variant now dominant in many countries.

The number of confirmed cases only reflects a fraction of the actual number of infections, with different countries also having varying counting practices and levels of testing.

Biggest spikes

On a country basis, Israel saw the biggest spike with a jump of 101 percent more daily cases.

Israel is among the most vaccinated countries in the world and has started administering booster jabs. It had seen its incidence rate plummet below 10 cases per 100,000 inhabitants, but this is now at 243.

Current Olympics host Japan followed with 97 percent more daily cases, then Turkey with 56 percent more, Pakistan with 54 percent and Morocco with a jump of 49 percent.

Biggest drops

Zimbabwe saw the biggest drop with 46 percent fewer daily cases, followed by the Netherlands with 44 percent, Brazil 28 percent, Rwanda 27 percent and Colombia with a drop of 26 percent.

Most new cases

The US saw the biggest number of new cases this week with 96,800, an increase of 44 percent.

It was followed by India (40,600, an increase of five percent), and Indonesia (33,900, a drop of 20 percent).

On a per capita basis the country that recorded the most new cases this week remained Fiji with 824 cases per 100,000 inhabitants, followed by Georgia (575) and Cuba (565).

Most deaths

Indonesia again recorded the highest number of daily deaths with 1,689, followed by Brazil (887) and Russia (790).

Daily deaths worldwide this week were at 9,382 per day, an increase of five percent.

Vaccinations

Japan led the vaccination race among countries with more than one million people, giving doses to 1.77 percent of its population every day this week.

Panama followed (1.72 percent), then Sri Lanka (1.70 percent), Malaysia (1.61 percent), Ecuador (1.26 percent), China (1.22 percent) and Saudi Arabia (1.15 percent).

While they are vaccinating more slowly, the countries with the most advanced vaccination drives are the United Arab Emirates with 172 first or second doses per 100 people, Israel, Canada, Chile and Singapore, all on 133, Denmark (130), Belgium (128) and the UK (126).

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The AMA has told the House Select Committee on Mental Health and Suicide Prevention Australia's mental health system is suffering from underfunding at all sector and government levels, and services are not coping with demand, even before the impact of COVID-19 is felt.

Calling for more investment into mental health care, AMA President Dr. Omar Khorshid said that although extra funding in the last budget was welcome, the providers of existing mental health services received no additional support despite overwhelming demand.

The situation in public mental health is even more dire, landing more people with severe mental health conditions in already over-stretched hospital emergency departments.

"There are not enough psychiatrists in Australia and there is likely to be increased demand for their services generated by the pandemic. We urgently need an alternative to emergency departments treating people experiencing acute mental ill-health."

"We know that mental health admissions to hospitals are the fastest growing of any hospital admission, increasing at an average rate of 4.8 percent each year from 2013-14 and the five following years, so that's a total growth of 26.4 percent over five years from 2013, accounting for an extra 6,073 admissions each year or a total of 30,366 for that period."

"People with mental health conditions are also staying longer in hospital—up to twice as long as people with heart conditions, for example, according to data from AIHW."

"Australia also has a serious shortage of child and adolescent child psychiatrists and we need a serious commitment to grow this cohort of the mental health workforce to support early detection."

"The May budget allocated $11 million for 30 new psychiatry training places and while this is welcome, it is woefully inadequate in the face of current and future needs. We'd need at least 260 by the year 2025."

"And we need to understand there is very high demand for mental health services in regional and rural areas and getting the workforce into these places requires urgent attention," Dr. Khorshid said.

Appearing alongside Dr. Khorshid, AMA NSW President Dr. Danielle McMullen said optimal mental health care is patient-centered, and General Practice has an essential role in responding to and coordinating treatment and care for people experiencing mental ill-health.

"GPs are frequently the first point of contact on someone's mental health journey and they need to be resourced to provide appropriate care and treatment pathways."

"We know investment in well-designed, medically governed health teams result in better health outcomes and General Practice can oversee stronger coordination of things like older persons' mental health, mental health nurses, psychologists, pediatricians, counselors and drug, alcohol and gambling support. These supports are all key aspects of a patient-centered mental health system," Dr. McMullen said.

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After long stretches with zero local cases—what Australians once jokingly referred to as "doughnut days"—a Sydney outbreak has now grown to 4,610.

Record numbers of new cases are being reported each day despite widespread lockdowns.

Slowly but surely, some local authorities have shifted to talking about containing the virus rather than beating it.

"Given where numbers are, given the experience of Delta overseas, we now have to live with Delta one way or another, and that is pretty obvious," said New South Wales Premier Gladys Berejiklian.

After 18 months of advocating "COVID zero", that represents a step-change in the country's approach.

For experts like Emma McBryde, an infectious diseases and statistical modelling expert at James Cook University, the shift in tone is a reflection of the new reality that Delta has brought.

"We're buying time, not getting back to COVID zero," she told AFP.

Like most experts she agrees that Australia's old virus toolbox—aggressive tracing and testing, snap lockdowns and extensive travel restrictions—while less effective, is still essential to stop exponential virus spread.

But, she said: "The goal now should be keeping COVID in check for long enough to get vaccinated."

Tony Blakely, an epidemiologist at the University of Melbourne, echoed those comments, telling public broadcaster ABC that Australia will "probably never" get back to zero transmission.

Game changer

Barring a few isolated Pacific islands and neighbouring New Zealand, few countries weathered the first 18 months of the coronavirus quite as well as Australia.

As the rest of the world hunkered down, got sick and lost loved ones, Australians flocked to bars, restaurants and the beach.

Occasionally, the virus jumped from hotel quarantine facilities into the community but aggressive tracing and testing, snap local lockdowns and domestic travel restrictions kept it in check.

Then came Delta.

In mid-June, a US flight crew infected a Sydney driver with the highly transmissible variant first detected in India.

Since then, the number of daily infections has climbed steadily despite a Sydney lockdown, now in its sixth week.

The outbreak has grown and clusters have popped up across the country.

Roughly 16 million Australians—almost two-thirds of the population—are now staying at home, just as Europe and North America emerge from virus-enforced hibernation.

Bun fight

The outbreak and strategy shift by New South Wales has spurred recriminations among Australian states and the federal government in Canberra.

Leaders have bickered about whether Sydney locked down too slowly, or too lightly.

Authorities in Victoria, Western Australia, South Australia and Queensland continue to try to stamp out new cases entirely.

But even those who advocate aggressive suppression admit the costs are rising and it has become harder.

"Australia's 'Zero COVID' strategy has allowed us to escape the worst of the pandemic so far: our death toll has been among the world's lowest, our recession among the shortest," said a recent report from the Grattan Institute, a public policy think tank.

"We've faced fewer restrictions on our daily lives than almost anywhere else. But we have paid a heavy price. We are shut off from the rest of the world, and we have frequently been locked down."

"The more infectious Delta variant is making Zero COVID even harder to maintain. Australians have supported a hard-line approach, but they are also tired and frustrated."

Despite the bickering, most mainstream voices are united in seeing vaccines as the ultimate way out.

But barely 20 percent of Australians are vaccinated, in part because of poor planning, in part bad luck.

The government bet on a University of Queensland vaccine that—while likely effective—was dropped because it caused a false positive HIV test in recipients.

It also bet on the AstraZeneca vaccine, which is produced locally and is in plentiful supply but is seen by many Australians as inferior to Pfizer, which was ordered in small numbers.

According to the Grattan Institute only 10 percent of Australians are "entrenched anti-vaxxers".

For the rest, McBryde said the situation may have to get worse before they turn to AstraZeneca. "People are just unbelievably complacent," she said.

Fewer and fewer doughnut days may yet shake that complacency.

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From real fears sparked by side-effects, to fake studies and conspiracy theories, we take a look at anti-vax sentiment over the ages:

1796: First jab, first fears

Smallpox killed or disfigured countless millions for centuries before it was eradicated in 1980 through vaccination.

In 1796 the English physician Edward Jenner came up with the idea of using the milder cowpox virus on a child to stimulate immune response after he noticed milkmaids rarely got smallpox.

The process—coined "vaccinus" by Jenner (from cow in Latin)—was successful, but from the outset it provoked scepticism and fear.

Before Jenner a riskier method of inoculation known as "variolation" existed for smallpox, introduced to Europe from Ottoman Turkey by the English writer and wit Lady Mary Wortley Montagu.

1853: Mandatory shot

In Britain the smallpox vaccine became compulsory for children in 1853, making it the first-ever mandatory jab and triggering strong resistance.

Opponents objected on religious grounds, raised concerns over the dangers of injecting animal products, and claimed individual freedoms were being infringed.

A "conscience clause" was introduced in 1898 allowing sceptics to avoid vaccination.

1885: Pasteur and rabies

At the end of the 19th century, the French biologist Louis Pasteur developed a vaccine against rabies by infecting rabbits with a weakened form of the virus.

But again the process sparked mistrust and Pasteur was accused of seeking to profit from his discovery.

1920s: Vaccines heyday

Vaccines flourished in the 1920s—shots were rolled out against tuberculosis with the BCG in 1921, diphtheria in 1923, tetanus in 1926 and whooping cough in 1926.

It was also the decade that aluminium salts began to be used to increase the effectiveness of vaccines.

But more than half a century later these salts became the source of suspicion, with a condition causing lesions and fatigue called macrophagic myofasciitis thought to be caused by them.

1998: Fake autism study

A study published in the top medical journal The Lancet in 1998 suggested there was a link between autism and the measles, mumps and rubella shot known as the MMR vaccine.

The paper by Andrew Wakefield and colleagues was revealed years later to be a fraud and retracted by the journal, with Wakefield struck off the medical register.

Despite subsequent studies demonstrating the absence of any such link, the bogus paper is still a reference for anti-vaxxers and it left its mark.

Measles killed 207,500 people in 2019, a jump of 50 percent since 2016 with the World Health Organization warning that vaccine coverage is falling globally.

2009: Swine flu scare

The discovery in 2009 of "Swine flu", or H1N1, caused by a virus of the same family as the deadly Spanish flu, caused great alarm.

But H1N1 was not as deadly as first feared and millions of vaccine doses produced to fight it were destroyed, fuelling mistrust towards vaccination campaigns.

Matters were made worse by the discovery that one of the vaccines, Pandemrix, raised the risk of narcolepsy.

Of 5.5 million people given the vaccine in Sweden, 440 had to be compensated after developing the sleep disorder.

2020: Polio conspiracy theories

Eradicated in Africa since August 2020 thanks to vaccines, polio is still a scourge in Pakistan and Afghanistan where the disease, which causes paralysis in young children, remains endemic.

Anti-vaccine conspiracy theories have allowed it to continue to destroy lives.

In Afghanistan, the Taliban banned vaccine campaigns, calling them a Western plot to sterilise Muslim children.

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The research found “an almost complete loss of stability over the last century” of the currents that researchers call the Atlantic meridional overturning circulation (AMOC). The currents are already at their slowest point in at least 1,600 years, but the new analysis shows they may be nearing a shutdown.

Such an event would have catastrophic consequences around the world, severely disrupting the rains that billions of people depend on for food in India, South America and West Africa; increasing storms and lowering temperatures in Europe; and pushing up the sea level off eastern North America. It would also further endanger the Amazon rainforest and Antarctic ice sheets.

The complexity of the AMOC system and uncertainty over levels of future global heating make it impossible to forecast the date of any collapse for now. It could be within a decade or two, or several centuries away. But the colossal impact it would have means it must never be allowed to happen, the scientists said.

“The signs of destabilisation being visible already is something that I wouldn’t have expected and that I find scary,” said Niklas Boers, from the Potsdam Institute for Climate Impact Research in Germany, who did the research. “It’s something you just can’t [allow to] happen.”

It is not known what level of CO2 would trigger an AMOC collapse, he said. “So the only thing to do is keep emissions as low as possible. The likelihood of this extremely high-impact event happening increases with every gram of CO2 that we put into the atmosphere”.

Scientists are increasingly concerned about tipping points – large, fast and irreversible changes to the climate. Boers and his colleagues reported in May that a significant part of the Greenland ice sheet is on the brink, threatening a big rise in global sea level. Others have shown recently that the Amazon rainforest is now emitting more CO2 than it absorbs, and that the 2020 Siberian heatwave led to worrying releases of methane.

The world may already have crossed a series of tipping points, according to a 2019 analysis, resulting in “an existential threat to civilisation”. A major report from the Intergovernmental Panel on Climate Change, due on Monday, is expected to set out the worsening state of the climate crisis.

Boer’s research, published in the journal Nature Climate Change, is titled “Observation-based early-warning signals for a collapse of the AMOC”. Ice-core and other data from the last 100,000 years show the AMOC has two states: a fast, strong one, as seen over recent millennia, and a slow, weak one. The data shows rising temperatures can make the AMOC switch abruptly between states over one to five decades.

The AMOC is driven by dense, salty seawater sinking into the Arctic ocean, but the melting of freshwater from Greenland’s ice sheet is slowing the process down earlier than climate models suggested.

Boers used the analogy of a chair to explain how changes in ocean temperature and salinity can reveal the AMOC’s instability. Pushing a chair alters its position, but does not affect its stability if all four legs remain on the floor. Tilting the chair changes both its position and stability.

Eight independently measured datasets of temperature and salinity going back as far as 150 years enabled Boers to show that global heating is indeed increasing the instability of the currents, not just changing their flow pattern.

The analysis concluded: “This decline [of the AMOC in recent decades] may be associated with an almost complete loss of stability over the course of the last century, and the AMOC could be close to a critical transition to its weak circulation mode.”

Levke Caesar, at Maynooth University in Ireland, who was not involved in the research, said: “The study method cannot give us an exact timing of a possible collapse, but the analysis presents evidence that the AMOC has already lost stability, which I take as a warning that we might be closer to an AMOC tipping than we think.”

David Thornalley, at University College London in the UK, whose work showed the AMOC is at its weakest point in 1,600 years, said: “These signs of decreasing stability are concerning. But we still don’t know if a collapse will occur, or how close we might be to it.”

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According to current estimates, the Delta variant could be more than twice as transmissible as the original strain of SARS-CoV-2. To find out why, epidemiologist Jing Lu at the Guangdong Provincial Center for Disease Control and Prevention in Guangzhou, China, and his colleagues tracked 62 people who were quarantined after exposure to COVID-19 and who were some of the first people in mainland China to become infected with the Delta strain.

The team tested study participants’ ‘viral load’ — a measure of the density of viral particles in the body — every day throughout the course of infection to see how it changed over time. Researchers then compared participants’ infection patterns with those of 63 people who contracted the original SARS-CoV-2 strain in 2020.

In a preprint posted 12 July1, the researchers report that virus was first detectable in people with the Delta variant four days after exposure,compared with an average of six days among people with the original strain, suggesting that Delta replicates much faster. Individuals infected with Delta also had viral loads up to 1,260 times higher than those in people infected with the original strain.

The combination of a high number of viruses and a short incubation period makes sense as an explanation for Delta’s heightened transmissibility, says epidemiologist Benjamin Cowling at the University of Hong Kong. The sheer amount of virus in the respiratory tract means that superspreading events are likely to infect even more people, and that people might begin spreading the virus earlier after they become infected.

And the short incubation makes contact tracing more difficult in countries such as China, which systematically tracks each infected person’s contacts and require them to quarantine. “Putting it all together, Delta’s really difficult to stop,” Cowling says.

Genetics researcher Emma Hodcroft at the University of Bern in Switzerland agrees that the mechanism makes sense. She and Cowling both suspect that estimates of the exact difference in viral load between Delta and the original strain are likely to shift as more scientists study the virus in various populations.

A number of other questions about the Delta variant remain unanswered. It’s still unclear, for instance, whether it is more likely to cause severe disease than the original strain, and how good it is at evading the immune system. Hodcroft expects some of this information will emerge as researchers look more closely at broader and more diverse populations of people infected with Delta and other variants. “This virus has surprised us,” she says.

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For a second straight day, New South Wales premier Gladys Berejiklian said Australia's most populous state hit a new peak with 291 cases detected.

"At least 50 of those were infectious in the community," Berejiklian said, foreshadowing more cases to come, despite a lockdown that is now in its sixth week.

"I'm expecting higher case numbers in the next few days, and I just want everybody to be prepared for that," she said.

Roughly 60 percent of Australia's 25 million residents are currently in lockdown, as the country tries to curb the spread of a virulent Delta variant outbreak.

Melbourne became the latest major city to shutter late Thursday, after Victoria state premier Dan Andrews issued stay-at-home orders for the sixth time in this pandemic.

"To be really frank, we don't have enough people that have been vaccinated and, therefore, this is the only option available to us," he said.

Barely 20 percent of Australians have been fully vaccinated, due to an acute lack of supply and pockets of vaccine hesitancy.

With cases rising and lockdowns seemingly able to slow, but not stop the spread, there are growing questions about whether Australia can return to the "COVID zero" status it enjoyed for much of the last 18 months.

"Given where numbers are, given the experience of Delta overseas, we now have to live with Delta one way or another, and that is pretty obvious," said Berejiklian.

She said returning to zero cases would be "a challenge" but "that has to be our aspiration, we have to try to get down as low as we can."

Meanwhile, there are signs that Australians are tiring of on-again-off-again restrictions that have marked pandemic life, although compliance with lockdown rules is still widespread.

"I'm not saying we're doing super well but we're keeping our heads above water," Melbourne market trader Linda told AFP Friday.

"I'm starting to feel like today it's starting to hit me harder than any other lockdown. Hang on, I haven't seen my family for such a long time."

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Filip K. Swirski, director of the Cardiovascular Research Institute at the Icahn School of Medicine at Mount Sinai, outlined what is already known about the interaction between lifestyle, the brain, and cardiovascular health, and what areas scientists are still working on. The former Harvard Medical School professor spoke Thursday at a virtual event in the Topics in Bioengineering series presented by the Harvard John A. Paulson School of Engineering and Applied Sciences.

Swirski acknowledged that "there is no question" that genetics play a role in cardiovascular health, but in the last several years, four risk factors—stress, sleep interruption or fragmentation, diet, and sedentary lifestyle—have been clearly identified as contributing to atherosclerosis, commonly referred to as hardening of the arteries, which can lead to a variety of complications, including death.

Current and ongoing research is seeking to uncover the mechanism by which these factors "alter the tissue on the cellular and molecular level," he said, focusing on "inter-organ communication." The goal, he said, is to "discover pathways to design therapeutic approaches and also change health policy," much as research around smoking shaped public policy.

Briefly summarizing the current findings on sleep—"on average, we're not getting enough"—as well as the widely recognized roles of diet and lifestyle, Swirski then settled in for a deep dive into the role of stress. Citing not-yet-published research, he used slides to illustrate how neutrophils—a type of white blood cell—can be seen "swarming" in the ears of mice subjected to stress. This is not surprising, he said, referencing a Curt Richter Award-winning study 10 years ago that showed the redistribution of such immune cells due to stress.

Current research is taking these studies down to a cellular level, however, examining the movements of different blood components associated with the immune system both during induced acute stress and in the recovery following. For example, in response to stress the levels of neutrophils appear to increase in the lung, liver, and spleen—but decrease in bone marrow. "It may be the case that the source of the neutrophils is the bone marrow," he said. "And that they're mobilizing very quickly" to the other organs.

However, two other components—B and T cells—increase in bone marrow under acute stress. While emphasizing that this work is still ongoing, Swirski offered a hypothesis. "What we think is going on is that in response to acute stress, there's a mass migration of B and T cells into the bone marrow," he said. "They hide in the bone marrow, perhaps as a safe haven, and, after the storm passes, they start to return to the blood."

Additional research is seeking to understand the mechanisms for these changes. Because these large-scale shifts are induced by stress, he pointed out, "Stress centers in the brain are the likely culprits." Ongoing studies on mice are suggesting that the two primary stress centers seem to have different functions. The hypothalamic pituitary adrenal axis, for example, controls two of these blood components, lymphocytes and monocytes, but the sympathetic nervous system controls another, noradrenaline release.

Such a division was "unexpected," said Swirski, and raises both further questions and avenues to explore. "We think that these processes have evolved for reasons that benefit the host, but they can also backfire," he said.

Questioned after his presentation about the adaptive nature of these responses, Swirski discussed the evolutionary importance of stress. Not only does stress provoke the palpable "fight, flight, or freeze" reaction that can save us when threatened, on a molecular level these immune-related responses may have helped our bodies fight off antigens—such as the germs on the teeth of a predator after a bite.

However, these adaptive responses have a price. Not only is recovery—the time it takes to revert to pre-stress levels—slow, but ongoing research indicates that with repeated stress, levels react increasingly quickly, jumping into emergency mode. "Keep in mind, there are two systems in our body—the immune system and the nervous system—that learn," said Swirski. "They require input and are very intertwined."

This has implications in the current pandemic. "There's a socio-economic component" to the health of our immune systems, he said, pointing out deleterious effect of "the stress of not being able to feed your family," among other factors. "Stressed mice die of COVID at a much higher-rate than non-stressed mice," he said.

"This permeates all of health and disease," Swirski concluded. "Some parts of stress are beneficial. We need stress, but it's that balance of positive and negative stress. It's a complicated issue."

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In the northern hemisphere, record breaking temperatures in the form of heat domes recently caused uncontrollable "firebombs," while unprecedented floods disrupted millions of people. Hundreds of lives have been lost due to heat stress, drownings and fire.

The twin catastrophic threats of climate change and a pandemic have created an "epoch of incredulity". It's not surprising many Australians are struggling to cope.

During the pandemic's first wave in 2020, we collected nationwide data from 5,483 adults across Australia on how climate change affects their mental health. In our new paper, we found that while Australians are concerned about COVID-19, they were almost three times more concerned about climate change.

That Australians are very worried about climate change is not a new finding. But our study goes further, warning of an impending epidemic of mental health related disorders such as eco-anxiety, climate disaster-related post traumatic stress disorder (PTSD), and future-orientated despair.

Which Australians are most worried?

We asked Australians to compare their concerns about climate change, COVID, retirement, health, aging and employment, using a four-point scale (responses ranging from "not a problem" to "very much a problem").

A high level of concern about climate change was reported across the whole population regardless of gender, age, or residential location (city or rural, disadvantaged or affluent areas). Women, young adults, the well-off, and those in their middle years (aged 35 to 54) showed the highest levels of concern about climate change.

The latter group (aged 35 to 54) may be particularly worried because they are, or plan to become, parents and may be concerned about the future for their children.

The high level of concern among young Australians (aged 18 to 34) is not surprising, as they're inheriting the greatest existential crisis faced by any generation. This age group have shown their concern through numerous campaigns such as the School Strike 4 Climate, and several successful litigations.

Of the people we surveyed in more affluent groups, 78% reported a high level of worry. But climate change was still very much a problem for those outside this group (42%) when compared to COVID-related worry (27%).

We also found many of those who directly experienced a climate-related disaster—bushfires, floods, extreme heat waves—reported symptoms consistent with PTSD. This includes recurrent memories of the trauma event, feeling on guard, easily startled and nightmares.

Others reported significant pre-trauma and eco-anxiety symptoms. These include recurrent nightmares about future trauma, poor concentration, insomnia, tearfulness, despair and relationship and work difficulties.

Overall, we found the inevitability of climate threats limit Australians' ability to feel optimistic about their future, more so than their anxieties about COVID.

How are people managing their climate worry?

Our research also provides insights into what people are doing to manage their mental health in the face of the impending threat of climate change.

Rather than seeking professional mental health support such as counselors or psychologists, many Australians said they were self-prescribing their own remedies, such as being in natural environments (67%) and taking positive climate action (83%), where possible.

Many said they strengthen their resilience through individual action (such as limiting their plastic use), joining community action (such as volunteering), or joining advocacy efforts to influence policy and raise awareness.

Indeed, our research from earlier this year showed environmental volunteering has mental health benefits, such as improving connection to place and learning more about the environment.

It's both ironic and understandable Australians want to be in natural environments to lessen their climate-related anxiety. Events such as the mega fires of 2019 and 2020 may be renewing Australians' understanding and appreciation of nature's value in enhancing the quality of their lives. There is now ample research showing green spaces improve psychological well-being.

An impending epidemic

Our research illuminates the profound, growing mental health burden on Australians.

As the global temperature rises and climate-related disasters escalate in frequency and severity, this mental health burden will likely worsen. More people will suffer symptoms of PTSD, eco-anxiety, and more.

Of great concern is that people are not seeking professional mental health care to cope with climate change concern. Rather, they are finding their own solutions. The lack of effective climate change policy and action from the Australian government is also likely adding to the collective despair.

As Harriet Ingle and Michael Mikulewicz—a neuropsychologist and a human geographer from the UK—wrote in their 2020 paper: "For many, the ominous reality of climate change results in feelings of powerlessness to improve the situation, leaving them with an unresolved sense of loss, helplessness, and frustration."

It is imperative public health responses addressing climate change at the individual, community, and policy levels, are put into place. Governments need to respond to the health sector's calls for effective climate related responses, to prevent a looming mental health crisis.

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Google announces it might have created physics-breaking 'Time Crystals'

Companies may be investing in production capacity that will outpace demand.

The hydrogen economy is about to get weird

Life only works with chemicals that have the right orientations—but chemists don't.

The central dogma of molecular biology holds that DNA gets transcribed into RNA, which then gets translated into proteins. Of course, there are exceptions—some viruses, like coronaviruses, forego DNA altogether and encode their genetic information in RNA genomes. Other viruses, like HIV, have RNA genomes that must be copied into DNA and then transcribed back into RNA before being made into proteins. But as a general rule, "DNA to RNA to protein" describes how information moves within cells.

 

A unique property of biological molecules is that they have handedness. Naturally occurring molecules occur in roughly equal mixtures of left- and right-handed varieties. This means that molecules can have identical atoms and shapes but cannot be superimposed one upon the other. Instead, they are mirror images of each other, like our right and left hands.

 

(This can be difficult to envision, which is why pre-meds taking organic chemistry in college spend so much time playing with those ball-and-stick molecular models.)

 

Unlike naturally occurring molecules, biological molecules are all one-sided. Our nucleic acids are all right-handed (referred to as D, from the Latin dexter), and proteins are all left-handed (L for laevus). This is such a unique feature of biological molecules that SETI uses it as a hallmark signature when it is searching for life. Louis Pasteur first noticed this one-sidedness in 1848, and scientists have been speculating about mirror life ever since. Now, they have gotten one step closer to creating it.

A jump to the left, a step to the right

Ting F. Zhu’s lab at Tsinghua University in Beijing has been synthesizing all of the components necessary for a mirror-image central dogma. The researchers have used synthetic chemical methods to synthesize short stretches of mirror-image L-DNA and L-RNA. But it’s more efficient to make nucleic acids using enzymes called polymerases—that is, proteins. The naturally occurring proteins we use for this only work with D-DNA.

 

So the lab used synthetic chemistry to make mirror-image D-protein DNA polymerases and used them to replicate short strands of L-DNA. In other words, a mirror image of a normal protein can copy the mirror image of normal DNA. Separately, the researchers tweaked their D-protein DNA polymerases to turn them into RNA polymerases so they could transcribe short strands of L-DNA into L-RNA. These polymerases were amazing proofs of concept, but they were inefficient and error prone, and they could only generate short pieces of L-nucleic acids.

 

Now, the Zhu lab has chemically synthesized a mirror-image of an enzyme called Pfu DNA polymerase, which is commonly used for PCR reactions. This enzyme is heat-resistant and has very high fidelity. But it’s also about twice as big as the polymerases the researchers had made before; the scientists had to synthesize it in two pieces and then link them together.

 

The researchers used the enzyme to copy a mirror-image gene that is 1,500 bases long, about 10 times as long as the earlier polymerases could manage. The gene the researchers chose encodes ribosomal RNA, so when they can transcribe it, they will have one part of a mirror-image ribosome. Once they get all the parts, they won’t have to rely on bulky synthetic methods to make mirror-image D-proteins anymore.

Long-lived

One potential use of mirror-image L-DNA is that, like its natural counterpart D-DNA, it can be used as a compact and reliable means of information storage. But unlike its natural counterpart, it can’t be degraded by enzymes, because no one has made mirror-image D-DNases that can degrade them yet. To demonstrate one application, Zhu made DNA barcodes for environmental water samples—you can think of the bar codes as using the sequence of bases to indicate things like “lotus pond, Beijing.” When he tried to amplify the normal, D-DNA barcode from a pond sample a day after adding it, it could not be found; it had been degraded. The mirror-image L-DNA barcode was still detectable a year later.

 

As if that weren’t clever enough, he and his lab ventured into steganography. They made a key molecule of DNA that is half-D and half-L; half-normal and half-mirror image. As a reference text, they encoded Pasteur’s 1860 paragraph speculating about mirror life into D-DNA. If the key is read with a normal DNA polymerase, it gives an error message when decoded using the Pasteur text. But if it is read with an L-DNA polymerase, it gives the secret message from the mirror DNA.

 

Obviously, Zhu’s team now intends to make mirror-image ribosomes to translate mirror-image mRNAs into mirror-image proteins. This is no small feat—ribosomes are very complex, involving dozens of proteins and several RNA molecules—but still, the researchers have gotten pretty far pretty fast. And of course, they also plan to make mirror-image D-DNases to “eliminate the information-storing L-DNA molecules after use as a biocontainment strategy.”

 

Nature Biotechnology, 2021 DOI: 10.1038/s41587-021-00969-6

 

 

Holding a mirror to life’s key molecules

• The bodies of some Tibetan monks remain "fresh" after what appears to be their death.

• Their fellow monks say they're not dead yet but in a deep, final meditative state called "thukdam."

• Science has not found any evidence of lingering EEG activity after death in thukdam monks.

It's definitely happening, and it's definitely weird. After the apparent death of some monks, their bodies remain in a meditating position without decaying for an extraordinary length of time, often as long as two or three weeks.

Tibetan Buddhists, who view death as a process rather than an event, might assert that the spirit has not yet finished with the physical body. For them, thukdam begins with a "clear light" meditation that allows the mind to gradually unspool, eventually dissipating into a state of universal consciousness no longer attached to the body. Only at that time is the body free to die.

Whether you believe this or not, it is a fascinating phenomenon: the fact remains that their bodies don't decompose like other bodies. (There have been a handful of other unexplained instances of delayed decomposition elsewhere in the world.)

The scientific inquiry into just what is going on with thukdam has attracted the attention and support of the Dalai Lama, the highest monk in Tibetan Buddhism. He has reportedly been looking for scientists to solve the riddle for about 20 years. He is a supporter of science, writing, "Buddhism and science are not conflicting perspectives on the world, but rather differing approaches to the same end: seeking the truth."

The most serious study of the phenomenon so far is being undertaken by The Thukdam Project of the University of Wisconsin-Madison's Center for Healthy Minds. Neuroscientist Richard Davidson is one of the founders of the center and has published hundreds of articles about mindfulness.

Davidson first encountered thukdam after his Tibetan monk friend Geshe Lhundub Sopa died, officially on August 28, 2014. Davidson last saw him five days later: "There was absolutely no change. It was really quite remarkable."

Credit: GrafiStart / Adobe Stock

The Thukdam Project published its first annual report this winter. It discussed a recent study in which electroencephalograms failed to detect any brain activity in 13 monks who had practiced thukdam and had been dead for at least 26 hours. Davidson was senior author of the study.

While some might be inclined to say, well, that's that, Davidson sees the research as just a first step on a longer road. Philosopher Evan Thompson, who is not involved in The Thukdam Project, tells Tricycle, "If the thinking was that thukdam is something we can measure in the brain, this study suggests that's not the right place to look."

In any event, the question remains: why are these apparently deceased monks so slow to begin decomposition? While environmental factors can slow or speed up the process a bit, usually decomposition begins about four minutes after death and becomes quite obvious over the course of the next day or so.

As the Dalai Lama said:

"What science finds to be nonexistent we should all accept as nonexistent, but what science merely does not find is a completely different matter. An example is consciousness itself. Although sentient beings, including humans, have experienced consciousness for centuries, we still do not know what consciousness actually is: its complete nature and how it functions."

Consciousness

As thukdam researchers continue to seek a signal of post-mortem consciousness of some sort, it's fair to ask what — and where — consciousness is in the first place. It is a question with which Big Think readers are familiar. We write about new theories all the time: consciousness happens on a quantum level; consciousness is everywhere.

So far, though, says Tibetan medical doctor Tawni Tidwell, also a Thukdam Project member, searches beyond the brain for signs of consciousness have gone nowhere. She is encouraged, however, that a number of Tibetan monks have come to the U.S. for medical knowledge that they can take home. When they arrive back in Tibet, she says, "It's not the Westerners who are doing the measuring and poking and prodding. It's the monastics who trained at Emory."

Source

In a final analysis from its Phase 3, or final stage, clinical trial, Moderna's COVID vaccine showed 93 percent efficacy at six months following the second dose.

The company is also carrying out clinical trials on three different COVID-19 boosters, with all of them producing high antibody levels against the original coronavirus strain and variants of concern, including Delta, originally identified in India.

"We are pleased that our COVID-19 vaccine is showing durable efficacy of 93% through six months, but recognize that the Delta variant is a significant new threat so we must remain vigilant," said CEO Stephane Bancel in a statement.

The statement added that Moderna expects to file its submission for full approval of its COVID vaccine with the US Food and Drug Administration this month.

The company has also begun studies for several other vaccines, including the flu, Zika, respiratory syncytial virus and others, and is developing a COVID vaccine that can be stored at fridge temperature.

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Consuming alcohol increases the risk of getting more cancers than previously thought, according to a major study, which also found that drinking coffee protects against liver cancer.

Alcohol consumption is linked to several cancers including those of the head and neck – mouth, pharynx and larynx – oesophageal and bowel, along with the more widely known connection with breast and liver cancer, according to an international team led by Imperial College London.

The study also showed that drinking at least one cup of coffee daily is associated with a lower risk of developing liver cancer and basal cell carcinoma of the skin, with the effects observed for both caffeinated and decaffeinated coffee.

Eating dairy products and wholegrains reduces the risk of colorectal cancer, the researchers found.

Giota Mitrou, the director of research and innovation at World Cancer Research Fund (WCRF), which funded the research, said: “This umbrella review confirms the evidence we have for alcohol and coffee in relation to cancer.

“Further research needs to better understand the mechanisms involved in the links between coffee and cancer as well as between alcohol and different cancer subtypes.”

She said people who were concerned about how their diet might affect their risk of cancer could consult the WCRF’s cancer prevention recommendations, which advocate limiting alcohol consumption, being a healthy weight and physically active, and enjoying a diet rich in wholegrains, vegetables, fruit and pulses.

Alcohol increases the risk of cancer because when it is metabolised, it breaks down into chemicals that can bind to DNA, resulting in mutations that could become cancerous.

Alcohol can also increase the levels of the hormones linked to the development of some types of breast cancer. In general, the more alcoholic drinks a person consumes, the higher their risk of developing one of the associated cancers, the scientists found.

The authors of the study are calling for more targeted public health policies that enable people to understand the link between drinking alcohol and cancer to encourage them to limit their consumption.

Coffee, conversely, is thought to have antioxidant and anti-inflammatory properties that may protect against diseases triggered by inflammation such as cancer.

The Imperial study looked at data from 860 reviews of published studies, which explored the association between food and nutrient intake and the risk of either developing or dying from 11 different cancers.

Although the researchers found weak links between cancer and most types of food and drink, the evidence for increased risk from alcohol consumption and reduced risk for coffee and dairy products was strong for the 11 cancers they looked at.

Source

The highly contagious Delta variant has driven the virus to return with a vengeance, the number of daily cases recorded worldwide rising by 68 percent since mid-June.

But as more of the world gets vaccinated against the coronavirus—particularly in wealthy countries—the number of deaths has increased at a slower rate, up 20 percent since the start of July, according to AFP's count.

In Australia, which had initially fended off the virus by slamming shut its borders, almost two-thirds of the 25 million population were in lockdown on Thursday as the country struggles to quash a Delta outbreak.

The country's two largest cities received a double blow in their efforts to retain "COVID Zero" status, with a record number of new cases in Sydney and Melbourne imposing its sixth lockdown.

Little more than a week after Melbourne's last lockdown ended, Victoria premier Daniel Andrews said he had "no choice" to lock down the city and the rest of the state.

"None of us are happy to be here, none of us," he said, citing the danger posed by eight new "mystery" cases that had yet to be traced.

Around two thousand protesters took to the streets chanting "no more lockdown", and the police responded in huge numbers, making arrests and using pepper spray to disperse the crowd.

Southeast Asia ravaged

The Delta variant has been running rampant in Southeast Asia, with Thailand recording 20,000 new daily cases for the first time on Wednesday—and again on Thursday.

The country also announced 160 deaths in 24 hours, as exhausted morgue workers struggle to cope with the mounting bodies.

"I've seen our personnel faint quite a few times lately so fatigue is definitely starting to set in and we're almost at our limits," forensic scientist Thanitchet Khetkham told AFP.

Indonesia's total COVID death toll passed 100,000 on Wednesday after it recorded 1,739 of the 10,245 fatalities registered worldwide, the global toll rising past 4.25 million.

Japan's capital Tokyo had a new record number of daily cases with 5,042, just three days before the end of the Olympics.

Africa also posted a new record with the 6,400 deaths in the week to August 1 representing the continent's most since the start of the pandemic, the World Health Organization said.

Habib Sagna, a cemetery manager in Senegal's Dakar, said that in a normal week, they would hold six or seven funerals.

"But now, we can do six or seven in a single day," he told AFP.

Vaccine inequality

The United States remains the country with the highest number of deaths and infections, however it said that it plans eventually to begin allowing fully vaccinated foreigners back in.

A White House official said that the US administration wants to reopen to visitors from abroad in a "safe and sustainable manner," though without specifying a timeframe.

On the other end of the spectrum China, where the virus first emerged in December 2019, was tightening its borders after recording its most new cases in six months.

China's immigration authority announced it would stop issuing ordinary passports and other documents needed for exiting the country in "non-essential and non-emergency" cases—but stopped short of issuing a blanket ban on overseas travel.

Greek authorities meanwhile announced Thursday new restrictions including a curfew on the island of Zante and the Crete city of Chania to fight surging infections.

In Spain, a curfew in Barcelona and most of Catalonia was extended for two weeks as hospitals come under pressure.

Also on Thursday, France became the latest country to announce it would rollout a third booster shot of a COVID vaccine from September, joining Israel and Germany.

President Emmanuel Macron's statement came just a day after the World Health Organization called on all nations to halt booster shots until at least the end of September to help ease the drastic inequity in dose distribution between rich and poor nations.

However Washington swiftly shot down the WHO's proposal.

"We definitely feel that it's a false choice and we can do both," White House press secretary Jen Psaki said.

Source

The findings match a Centers for Disease Control and Prevention study released a day earlier describing an outbreak centered on a town in Massachusetts. The researchers say it suggests fully vaccinated people who get sick with COVID-19 could potentially infect others.

Analysis of nearly 300 COVID-positive samples collected in Wisconsin between June 28 and July 24 showed no significant difference in "viral load" between 79 fully vaccinated people and 212 unvaccinated people. Both the vaccinated and unvaccinated study subjects had high viral loads at the time of their positive tests—levels shown in previous studies to be substantial enough to make them contagious to others.

"This is what the CDC's study showed last week in a single outbreak, but we are seeing the same in a more distributed sample across our state," says Katarina Grande, co-author of the new study and public health supervisor and COVID-19 Data Team lead at PHMDC.

While only 50 of the samples underwent genetic testing to determine which strain of the SARS-CoV-2 virus was present, 42 of them (84 percent) were identified as the delta variant, a strain of the virus that now appears to be more transmissible. Nearly all new COVID-19 cases in Wisconsin involve the delta variant, including among vaccinated people. Nearly one-third of the study's cases came from Dane County, home to the city of Madison and one of the nation's highest vaccination rates.

However, in Dane County, unvaccinated people are being diagnosed with COVID-19 at a rate two-and-a-half times greater than vaccinated people. Some breakthrough infections are expected in vaccinated people since no vaccine is 100 percent effective.

Vaccination remains critical, the researchers say, since the available vaccines against the virus are effective, successful—even against the delta variant, according to recent research—and an important way for almost everyone to help prevent new, dangerous cases.

"They're still working to keep people from becoming infected, though not necessarily as well as they were against earlier types of the virus," says David O'Connor, a UW School of Medicine and Public Health professor, co-author of the new study and, with Thomas Friedrich, a scientist at UW–Madison's AIDS Vaccine Research Laboratory, which has been collecting genetic samples from positive COVID tests since March of 2020. "As long as the vaccines are keeping people out of the hospitals, I would say they're working spectacularly well."

While the CDC study in Massachusetts focused on cases arising from a handful of large public gatherings, the new Wisconsin results came from more everyday circumstances.

"The predominant mode of transmission around here seems to be smaller gatherings and households," says Friedrich, a study co-author and a professor in the UW School of Veterinary Medicine. "There's nothing special about the particular circumstances, but we're seeing vaccinated people can become infected. And when they do, they can pass the virus on to other people."

The new results show that vaccinated people, who don't have much to fear in terms of severe disease, must be mindful that they can still be a source of infection for others.

"If there are people in their lives who are vulnerable, they still need to take care to keep those people safe," says Friedrich. "And so, we still need a community response to the pandemic that includes vaccinated people taking steps to prevent the unlikely—but not impossible—chance that they would transmit infection to others."

As with the CDC at a national level, the findings in Wisconsin of high viral load even in vaccinated people led PHMDC to return to recommending face coverings indoors for vaccinated and unvaccinated people.

"Our understanding has really shifted in the last week," Grande says. "We are always adjusting to emerging science, and delta is a different ballgame."

Source

NASA's Kepler space telescope captured the data in 2017.

The ANU researchers recorded the initial burst of light that is seen as the first shockwave travels through the star before it explodes.

Ph.D. scholar Patrick Armstrong, who led the study, said researchers are particularly interested in how the brightness of the light changes over time prior to the explosion. This event, known as the "shock cooling curve," provides clues as to what type of star caused the explosion.

"This is the first time anyone has had such a detailed look at a complete shock cooling curve in any supernova," Mr Armstrong, from the ANU Research School of Astronomy and Astrophysics, said.

"Because the initial stage of a supernova happens so quickly, it is very hard for most telescopes to record this phenomenon.

"Until now, the data we had was incomplete and only included the dimming of the shock cooling curve and the subsequent explosion, but never the bright burst of light at the very start of the supernova.

"This major discovery will give us the data we need to identify other stars that became supernovae, even after they have exploded."

The ANU researchers tested the new data against a number of existing star models.

Based on their modeling, the astronomers determined the star that caused the supernova was most likely a yellow supergiant, which was more than 100 times bigger than our sun.

Astrophysicist and ANU researcher Dr. Brad Tucker said the international team was able to confirm that one particular model, known as SW 17, is the most accurate at predicting what types of stars caused different supernovae.

"We've proven one model works better than the rest at identifying different supernovae stars and there is no longer a need to test multiple other models, which has traditionally been the case," he said.

"Astronomers across the world will be able to use SW 17 and be confident it is the best model to identify stars that turn into supernovas."

Supernovae are among the brightest and most powerful events we can see in space and are important because they are believed to be responsible for the creation of most of the elements found in our universe.

By better understanding how these stars turn into supernovae, researchers are able to piece together information that provides clues as to where the elements that make up our universe originate.

Although the Kepler telescope was discontinued in 2017, new space telescopes such as NASA's Transiting Exoplanet Survey Satellite (TESS) will likely capture more supernovae explosions.

"As more space telescopes are launched, we will likely observe more of these shock cooling curves," Mr Armstrong said.

"This will provide us with further opportunities to improve our models and build our understanding of supernovae and where the elements that make up the world around us come from."

The pre-print is available now in the Monthly Notices of the Royal Astronomical Society.

Source

Stonehenge is a megalithic monument located on the Salisbury Plain in Wiltshire England. Due to its protected status, it cannot be drilled, cut or subjected to chemical analysis, making study of its composition difficult. The monument was not always so well protected, however—back in 1958, workers hired to restore the monument drilled into one of the stones and extracted core samples. Parts of one of the cores were discovered in a museum in 2019; another was held as a souvenir by a worker who immigrated to the United States; and the third has never been found. Three years ago, the souvenir sample was returned to England and is being studied in this new effort.

The work involved slicing a part of the core sample into very thin wafers, which allowed for a wide variety of geochemical studies. Researchers also subjected the samples to CT scans, X-rays and microscopy.

They found that the stone was 99.7% quartz and that there were different grain sizes. One of them, which they describe as medium in size, formed "an interlocking mosaic of crystals," which the researchers noted served as a sort of cement and explained how the stones that make up Stonehenge have managed to survive for so long. The researchers suggest the Neolithic people who erected the monument may have known of the stones' durability and chose them for their longevity.

The researchers also found that the sediments from which the stones formed dated to approximately 66 to 23 million years ago.

Some of the grains could be dated as far back as 66 to 252 million years ago, and a few were formed as far back as 1 billion years ago.

Source

In 1958, Robert Phillips, a representative of the drilling company helping to restore Stonehenge, took the cylindrical core after it was drilled from one of Stonehenge's pillars – Stone 58. Later, when he emigrated to the United States, Phillips took the core with him.

Because of Stonehenge's protected status, it's no longer possible to extract samples from the stones. But with the core's return in 2018, researchers had the opportunity to perform unprecedented geochemical analyses of a Stonehenge pillar, which they described in a new study.

They found that Stonehenge's towering standing stones, or sarsens, were made of rock containing sediments that formed when dinosaurs walked the Earth. Other grains in the rock date as far back as 1.6 billion years.

Related: In photos: A walk through Stonehenge

"We have CT-scanned the rock, zapped it with X-rays, looked at it under various microscopes and analyzed its sedimentology and chemistry," said study lead author David Nash, a professor of physical geography at the University of Brighton in England.

"With the exception of thin-section analyses and a couple of the chemical methods, all of the techniques we used in the study were new both to Stonehenge and the study of sarsen stones in the UK," Nash told Live Science in an email.

Stonehenge's central circle of pillars was erected during the Neolithic period, about 2,500 years ago,

according to English Heritage, a nonprofit organization that manages historic monuments in England. 

"Sarsens were erected in two concentric arrangements – an inner horseshoe and an outer circle – and the bluestones [smaller monument stones] were set up between them in a double arc," English Heritage said on its website.

When the scientists peered through a microscope at thin slices of sarsen rock from Stone 58, they were surprised to discover that the stone was 99.7 percent quartz. A quartz "cement" held fine-to-medium quartz grains and formed "an interlocking mosaic of crystals," Nash said.

That made the rock more durable, and it may have been why the builders chose that type of rock for their massive monument thousands of years ago. 

"These cements are incredibly strong. I've wondered if the builders of Stonehenge could tell something about the stone properties, and not only chose the closest, biggest boulders, but also the ones that were most likely to stand the test of time," Nash said.

Above: Microscope image from the sarsen sample showing the tightly interlocking mosaic of quartz crystals that cement the rock together. The outlines of quartz sand grains are indicated by arrows.

Older than dinosaurs

The researchers' analysis also revealed clues about the ages of sediments in the rock, Nash said in the email.

"The sandy sediments within which the stone developed were deposited during the Paleogene period, 66 [million] to 23 million years ago, so the sarsens can be no older than this," he explained.

However, when the scientists compared ratios of neodymium isotopes – or atoms of the element with a different number of neutrons in the nucleus – in the samples, they found that certain sediments in the sarsen stone were even more ancient.

Some grains were likely eroded from rocks dating to the Mesozoic era (252 million to 66 million years ago), when they may have been trodden upon by dinosaurs. 

And some of the sand grains formed as long ago as 1 billion to 1.6 billion years ago, Nash said. 

While this analysis answered some questions about Stonehenge, other unresolved puzzles remain, among them the whereabouts of two more cores that were drilled from Stone 58 during the 1958 restoration, and which also vanished from the record. 

Workers at the Salisbury Museum in England discovered part of one of those cores in their collection in 2019, the researchers reported. Museum director Adrian Green contacted a representative at English Heritage, reporting the discovery of a portion of a core from Stone 58 "in a box marked '3x Stonehenge Stones from 'Treasure Box,'" according to the study.

The scientists investigated the Salisbury fragment alongside the Phillips core, and recorded its data in their study. However, "how and when it came to be at the museum was unknown," the authors wrote.

The location of the third core (and the rest of the core found at the Salisbury Museum) "is similarly unknown," the scientists said.

The findings were published August 4 in the journal PLOS One.

This article was originally published by Live Science. Read the original article here.

Source

Nineteen-year-old Jean Hilliard's car had stalled while returning to her parents' house after a night out.

Dressed in little more than a winter coat, mittens, and cowboy boots, she set out into the minus 30 Celsius (minus 22 Fahrenheit) night air to seek her friend's assistance.

At some point, she tripped and lost consciousness. For six hours, Hilliard's body lay in the cold, warmth draining away to leave her – by several accounts – "frozen solid".

"I grabbed her by the collar and skidded her into the porch," Nelson would report years later in a Minnesota Public Radio interview.

"I thought she was dead. Froze stiffer than a board, but I saw a few bubbles coming out of her nose."

If not for Nelson's prompt response, Hilliard might have just become one of the thousands of deaths chalked up to hypothermia each year. Instead, her tale has become a part of medical lore and a scientific curiosity.

How could a body survive being frozen solid?

Stories of people surviving freezing temperatures are unusual enough to be newsworthy but aren't exactly rare either. In fact, medical specialists in cold climates have a saying: "Nobody is dead until warm and dead".

The realization that extreme hypothermia isn't necessarily the end of a life has become the basis of therapy in itself. Under controlled conditions, lowering body temperature can cool down the metabolism and reduce the body's insatiable hunger for oxygen.

In medical settings, or on rare occasions elsewhere, a chilled body can put the brakes on the whole dying process long enough to deal with a low pulse, at least for a while.

Where Hilliard's account stands out is the extreme nature of her state of hypothermia.

Forget the fact her body temperature was barely 27 degrees Celsius, a full 10 degrees below that of a healthy human. She was – apparently – frozen. Her face was ashen, eyes solid, and her skin reportedly too hard to be punctured by a hypodermic needle.

In the words of George Sather, the physician who treated her, "The body was cold, completely solid, just like a piece of meat out of a deep freeze."

Yet within just a few hours, warmed by heating pads, Hilliard's body returned to a state of health. She was talking by noon, and with little more than some numb, blistered toes, was soon discharged to live an unremarkable life unaffected by her night as a human popsicle.

To friends and family in her community, it was all thanks to the power of prayer. But where does biology stand on the matter?

Unlike many materials, water takes up a greater volume as a solid than it does as a liquid. This expansion is bad news for body tissues caught in the cold, as their liquid contents risk swelling to the point of rupturing their containers.

Even a few stray ice crystals blooming in the wrong place can pierce cell membranes with their needle-like shards, reducing extremities to blackened patches of dead skin and muscle, or what we commonly know as frostbite.

Some animals have evolved some nifty adaptations to deal with the dangers of sharp, expanding ice crystals in sub-freezing conditions. Deep-sea fish known as Antarctic blackfin icefish produce glycoproteins as a kind of natural antifreeze, for instance.

The wood frog turns the contents of its cells into a syrup by flooding its body with glucose, thus resisting freezing and dehydration. Outside of their cells, water is free to turn into a solid, encasing tissues in ice and making them look, for all purposes, as solid as frog-shaped ice cubes.

Without anything more to go on than external observations, it's hard to say for sure how Hilliard's body withstood being frozen. Was there something unique about her body chemistry? Or even the make-up of her tissues?

Maybe. A far more important question is what exactly 'frozen' means in this case. Although low, Hilliard's core body temperature was reportedly still far above freezing. There's a world of difference between a metaphorical 'chilled to the bone' and literal solidified water in the veins.

The fact Hilliard's body felt solid is a common sign of severe hypothermia, as muscle rigidity increases to such an extent, it can even resemble rigor mortis, the stiffening that happens to a dead body.

That the surface of her body was cold and white, and even her eyes appeared glassy and 'solid', might also be less than surprising. The body will close off channels to blood vessels under the skin to keep organs functioning, to the point a body will look ashen and remain remarkably cold to the touch.

For medical staff persistent enough to try their luck using a smaller gauged hypodermic on heavily constricted veins, especially if they're covered by thin layers of dehydrated skin pressed tight against rigid muscles, we might even imagine a bent needle or two could result.

With little to go on other than a few surprised accounts, we can only speculate whether Hilliard's 'frozen' body was typical, if shocking, or indeed strangely unique in its ability to withstand such an extreme change of state. There can be no doubt, however, that she was fortunate.

The more we learn about the amazing things the human body can achieve, the less we might rely on good fortune to save lives like hers in the future and more on advances in medicine and rapid responses.

Source

There are still lots of unanswered questions about the event, from its overall timescale to its causes, but a new study offers some intriguing extra detail on the calamity: a sudden spike in oxygen levels in the world's oceans at the same time as this widespread extinction was happening.

The researchers behind the study think that the sudden burst of oceanic oxygenation occurred around the start of the Great Dying, and was spread across tens of thousands of years, before oxygen levels then began to steadily drop again.

"For the geological record, that's practically instantaneous," says Earth scientist Sean Newby from Florida State University (FSU).

"And then you can of course compare that to modern, human-induced climate change, where we're having huge, rapid changes in fractions of the time compared to this mass extinction."

Without the aid of a time machine, measuring oxygen levels in the ocean eons ago isn't easy, but the team analyzed thallium isotopes buried in ocean sediments as a way of estimating the chemical mix of seawater stretching back millions of years.

Scientists have previously observed a slow reduction in ocean oxygen levels – technically known as ocean anoxia – across the course of the Permian–Triassic extinction event, but this earlier spike in oxygenation hasn't been seen before.

The next question is what caused it and what it means. It could be possible that a rise and then sudden fall in ocean oxygen levels is more dangerous for marine species than a more gradual decline, the researchers suggest.

"There's previous work that's been done that shows the environment becoming less oxygenated leading into the extinction event, but it has been hypothesized as a gradual change," says Newby.

"We were surprised to see this really rapid oxygenation event coinciding with the start of the extinction and then a return to reducing conditions."

Next, the researchers want to carry out further studies using the same techniques, looking at other mass extinctions to see if similar large-scale shifts in ocean oxygenation might have occurred.

An intense injection of carbon dioxide into the atmosphere is likely to have brought about the Great Dying, scientists think, quite possibly originating from Siberian volcanic activity across a vast scale.

If we can understand more about how this oxygen spike came about – and how it might have contributed to the extinction event – then that's another piece of useful information we can use in assessing the ongoing impacts of the climate crisis today.

"The loss of oxygen is important because the organisms living now are adapted for high oxygen, but if you have low oxygen there's also many organisms that may be able to adapt," says marine biochemist Jeremy Owens, from FSU.

"Any rapid fluctuation in either direction will have an impact."

The research has been published in Nature Geoscience.

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WHO aims to get 10% of every country vaccinated by the end of September.

WHO calls for global moratorium on COVID boosters until end of September