Science
See Lucy Run, 3.2 Million Years Ago
More than three million years after her death, the early human ancestor known as Lucy is still divulging her secrets.
In 2016, an autopsy indicated that the female Australopithecus afarensis, whose partial remains were found in Ethiopia in 1974 and is considered the most complete hominin fossil found to date, died from a fall out of a tree. Seven years later, a virtual reconstruction of her leg and pelvic muscles — which are not preserved in fossils — revealed that she stood about three and a half feet tall, weighed between 29 and 93 pounds, and was capable of standing and walking upright, similar to modern humans.
A new study published in the journal Current Biology proposes that Lucy was capable of running, too. But she would not have been much of a marathoner and might have struggled to keep up with a contemporary couch potato in a 100-yard dash. “She was not a natural runner,” said Karl Bates, an evolutionary biomechanics researcher at the University of Liverpool and lead author of the paper. “In all probability, she could run only through short bursts of energy rather than long-distance chases.”
The fossil, which dates to 3.2 million years ago and represents 40 percent of Lucy’s skeleton, is often described as having a mix of human and ape features. “Her overall body size was much smaller than ours and her upper body larger, with longer arms and shorter legs,” Dr. Bates said. “Even after correction for differences in body size, she would have been much slower than people.” His team’s conclusions bolster the hypothesis that the ability of humans to run long distances is an adaptation that gave them an advantage in acquiring prey.
The analysis was drawn from computer-based movement simulations of Lucy’s leg muscles. The model used the surface area of her bones and the muscular architecture of modern apes to estimate her muscle mass. “The simulator experiments with millions and millions of different sequences until it finds the one that leads to the fastest speed with minimum energy cost,” Dr. Bates said. The researchers compared Lucy’s performances with those of a digital model of a modern human whose measurements echoed those of the 5-foot-9, 154-pound Dr. Bates, who is 38.
“The comparisons between humans and Lucy with the same muscle properties allowed us to give a sort of maximum and minimum speed estimate for Lucy,” he said. “It also allowed us to compare the effects that important anatomical features in human evolution had on running speed.”
The estimate for Lucy’s top running speed — with humanlike muscle configurations — was a relatively modest 11 m.p.h. That is roughly what a domestic pig could achieve over a quarter-mile, but far slower than modern humans, whose sprinting speeds often exceed 18 m.p.h. and peak at more than 27 m.p.h. in elite athletes. Dr. Bates speculated that in a 100-meter race, Usain Bolt, the world-record holder at that distance, would have beaten Lucy by somewhere between 50 and 80 meters.
Homo erectus, the first of our relatives with humanlike body proportions, evolved in Africa about 1.9 million years ago. The species was an endurance runner, built to chase down prey on the open savannas of Africa. Australopithecus afarensis fossils are typically found in areas that were primarily woodlands with patches of grassland. Built for short distances, Lucy would have relied on strategies other than pursuit hunting for gathering food, such as climbing trees.
“On the whole, the hominins were living in places that had lots of trees, bushes and shrubs,” said Denise Su, a paleontologist at the Institute of Human Origins in Tempe, Ariz. “Prey species in more closed habitats tend to hide and freeze as a response because there is a lot more cover, and you can’t run fast on landscapes with a lot of cover.”
Lacking the long, elastic Achilles tendons and shorter muscle fibers present in the legs of contemporary humans, Lucy would have had to work harder to move quickly. The benefit of the tendon, which connects the calf muscles to the heel bone, is that it acts like a giant spring, storing and releasing energy while we are in motion and producing an efficient running gait. The Achilles on an ape is little more than stub.
When humanlike ankle muscles were added to the cyber Lucy, the amount of energy that she expended was comparable to that of other animals of similar stature. But tack on apelike ankle muscles, and she would have spent three times as much energy running as a modern human.
“At this point in time of our evolution, we were just bipedal apes running around on the landscape,” Dr. Su said. “Given the kinds of habitats in which our early ancestors lived, this study suggests that the ability to run fast was not an adaptation that would have been important for Lucy’s survival.”
Science
Washington state resident dies of new H5N5 form of bird flu
The first person infected with the H5N5 bird flu has died, according to health officials in Washington.
The person, who lived in Grays Harbor County, had been hospitalized earlier this month in Kings County, where Seattle is located.
Officials from the Washington State Department of Health did not release the person’s name, age or gender. According to a news release from Grays Harbor County health officials last week, the person was considered “older” and had underlying health conditions. Their symptoms included a high fever, confusion and trouble breathing.
The person had a backyard flock consisting of mixed domestic poultry.
Testing by the health department found virus in the “environment of the flock … making exposure to the domestic poultry, their environment, or wild birds the most likely source of exposure for this patient.”
Officials at the state’s health department said they were monitoring other people who were exposed to the flock and environment.
This particular strain of bird flu, H5N5, had never been seen in a person before. It appeared first in 2023, infecting birds and mammals in eastern Canada.
According to research published last year on the novel strain, some infected animals carried a key mutation in the virus that allows it to transfer more easily between mammals.
Epidemiologists and virologists worry that avian influenza could generate a pandemic if allowed to spread and mutate. For instance, the H5N1 virus circulating in dairy cattle in North America is one mutation away from being able to spread easily between people.
Every time a bird flu virus infects a person, concerns grow that it could change, becoming more transmissible or more deadly. For instance, if a sickened person also has another flu virus replicating in their body, there’s concern the viruses could exchange genetic material. Just by having an opportunity to replicate and evolve millions of times in the human body, it could acquire deadly mutations.
Health officials say the risk to the public remains low and that no other people involved have tested positive for avian influenza. They say there is no evidence of transmission of the virus between people, but they are monitoring anyone who was in close contact with the patient.
Science
CDC replaces website on vaccines and autism with false and misleading statements
The U.S. Centers for Disease Control and Prevention has altered its website on autism and vaccines, removing unequivocal statements that immunizations don’t cause the neurodevelopmental disorder and replacing them with inaccurate and misleading information about the links between the shots and autism.
Until Wednesday, the CDC page, “Autism and Vaccines,” began: “Studies have shown that there is no link between receiving vaccines and developing autism spectrum disorder (ASD).”
This was followed, in large font, by the blunt statement: “Vaccines do not cause autism.”
The rest of the page summarized some of the CDC’s own studies into autism and vaccine ingredients, none of which found any causal links between the two.
On Wednesday, the page was altered so that it now begins: “The claim ‘vaccines do not cause autism’ is not an evidence-based claim because studies have not ruled out the possibility that infant vaccines cause autism.”
The words “Vaccines do not cause autism” still appear near the top, but with an asterisk that leads to a note at the bottom.
“The header ‘Vaccines do not cause autism’ has not been removed due to an agreement with the chair of the U.S. Senate Health, Education, Labor, and Pensions Committee that it would remain on the CDC website,” the site states.
The chair of that committee, Sen. Bill Cassidy (R-La.), cast the deciding vote to advance Robert F. Kennedy Jr.’s appointment as Health and Human Services secretary, in exchange for Kennedy’s promise that he wouldn’t erode public confidence in vaccines.
“What parents need to hear right now is vaccines for measles, polio, hepatitis B and other childhood diseases are safe and effective and will not cause autism. Any statement to the contrary is wrong, irresponsible, and actively makes Americans sicker,” Cassidy said in a post on X on Thursday afternoon. “Families are getting sick and people are dying from vaccine-preventable deaths, and that tragedy needs to stop.” Cassidy’s office did not immediately respond to further requests for comment Thursday.
“Studies supporting a link have been ignored by health authorities,” HHS spokesman Andrew Dixon said in an email. “We are updating the CDC’s website to reflect gold standard, evidence-based science.”
The news was met with outrage and alarm by scientists and advocates.
“Can we trust what’s coming from CDC anymore? I don’t know the answer to that question,” said Dr. Sean O’Leary, chair of the infectious disease committee at the American Academy of Pediatrics, adding that the website change reflects a “tragic moment” for U.S. public health.
“We are appalled to find that the content on the CDC webpage ‘Autism and Vaccines’ has been changed and distorted, and is now filled with anti-vaccine rhetoric and outright lies about vaccines and autism,” the nonprofit Autism Science Foundation said in a statement. “The CDC’s previous science- and evidence-based website has been replaced with misinformation and now actually contradicts the best available science.”
Alison Singer, the organization’s co-founder and president, expressed further frustration.
“Just like we no longer study whether the Earth is flat, at some point with regard to autism and vaccines, you have to call it and say ‘enough is enough,’” Singer said. “We don’t have an unlimited amount of money with which to study autism, and if we keep asking the same questions, we will never find the true causes of autism.”
The current CDC page now says the rise in autism diagnoses correlates with an increase in the number of vaccines given to infants. Multiple researchers have argued that the rise in autism spectrum disorder diagnoses is better explained by an expanding diagnostic definition of the disorder, along with better monitoring and diagnosis for more children.
“This issue has been studied exhaustively, and it has been shown over and over again that vaccines do not cause autism,” said Colin Killick, executive director of the Autistic Self-Advocacy Network. “This administration continues to lie about autism in ways that endanger both our community and the broader population.”
Science
California regulators approve rules to curb methane leaks and prevent fires at landfills
In one of the most important state environmental decisions this year, California air regulators adopted new rules designed to reduce methane leaks and better respond to disastrous underground fires at landfills statewide.
California Air Resources Board members voted 12-0 on Thursday to approve a batch of new regulations for the state’s nearly 200 large landfills, designed to minimize the release of methane, a powerful greenhouse gas produced by decomposing organic waste. Landfills are California’s second-largest source of methane emissions, following only the state’s large dairy cow and livestock herds.
The new requirements will force landfill operators to install additional pollution controls; more comprehensively investigate methane leaks on parts of landfills that are inaccessible with on-the-ground monitoring using new technology like drones and satellites; and fix equipment breakdowns much faster. Landfill operators also will be required to repair leaks identified through California’s new satellite-detection program.
The regulation is expected to prevent the release of 17,000 metric tons of methane annually — an amount capable of warming the atmosphere as much as 110,000 gas-fired cars driven for a year.
It also will curtail other harmful landfill pollution, such as lung-aggravating sulfur and cancer-causing benzene. Landfill operators will be required to keep better track of high temperatures and take steps to minimize the fire risks that heat could create.
There are underground fires burning in at least two landfills in Southern California — smoldering chemical reactions that are incinerating buried garbage, releasing toxic fumes and spewing liquid waste. Regulators found explosive levels of methane emanating from many other landfills across the state.
During the three-hour Air Resources Board hearing preceding the vote, several Californians who live near Chiquita Canyon Landfill — one of the known sites where garbage is burning deep underground — implored the board to act to prevent disasters in other communities across the state.
“If these rules were already updated, maybe my family wouldn’t be sick,” said Steven Howse, a 27-year resident of Val Verde. “My house wouldn’t be for sale. My close friend and neighbor would still live next door to me. And I wouldn’t be pleading with you right now. You have the power to change this.”
Landfill operators, including companies and local governments, voiced their concern about the costs and labor needed to comply with the regulation.
“We want to make sure that the rule is implementable for our communities, not unnecessarily burdensome,” said John Kennedy, a senior policy advocate for Rural County Representatives of California, a nonprofit organization representing 40 of the state’s 58 counties, many of which own and operate landfills. “While we support the overarching goals of the rule, we remain deeply concerned about specific measures including in the regulation.”
Lauren Sanchez, who was appointed chair of the California Air Resources Board in October, recently attended the United Nations’ COP30 climate conference in Brazil with Gov. Gavin Newsom. What she learned at the summit, she said, made clear to her that California’s methane emissions have international consequences, and that the state has an imperative to reduce them.
“The science is clear, acting now to reduce emissions of methane and other short-lived climate pollutants is the best way to immediately slow the pace of climate change,” Sanchez said.
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