CNN10: The big stories of Monday 5/19, explained in 10 minutes
Today on CNN 10, we find out the first thing a rescued hiker requested after spending weeks missing in the wilderness. We'll also learn why scientists are predicting a smelly aquatic plant will wash up on some shores in record numbers, before learning about a unique student led program that's reviving the population of an important fish species. Then we'll learn about one teen's triumph over tragedy through the sport of golf. All this and more on today's CNN 10!
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CBS News
20 minutes ago
- CBS News
Tiny fragment of asteroid giving Field Museum scientists a glimpse 4.6 billion years into the past
The Field Museum is the new temporary home to a tiny piece of pristine asteroid. The fragment of the asteroid Bennu, on loan from NASA, won't be on display for visitors, but will give scientists the chance to study an asteroid sample uncontaminated by Earth's atmosphere. A tiny, black fragment might not seem exciting, until a scientist explains it's a specimen from space. "It's an honor of a lifetime to be able to study this sample," said Field Museum curator Dr. Philipp Heck. How did Heck feel when the little rock first arrived at the museum and he held the vial containing the sample? "It was amazing. I was looking forward to that moment for a long time," he said. NASA's OSIRIS-REx mission was planned decades ago. In 2016, a spacecraft launched. In 2018, it arrived at Bennu, a near-Earth asteroid as wide as the Sears Tower is tall. The mission collected pieces of the asteroid and brought them back to Earth in 2023. "This is the first U.S. mission that sends a spacecraft to the asteroid and brings a sample back to Earth," said University of Chicago graduate student Yuke Zheng, who is part of the OSIRIS-REx sample analysis team. "It's a tiny, dark, black fragment that is fragile, so we want to protect it very carefully." She'll use the museum's scanning electron microscope to get an up-close look at a tiny sample of Bennu. "What struck me is how dark the sample is. I had never seen such a dark sample," Heck said. The fragment is like a time capsule, taking scientists back 4.6 billion years. "We believe Bennu contains part of the ingredients for life, and part of the ingredients of the formation of Earth," Heck said. Suddenly, a fragment at the bottom of a vial can have you pondering your place in the universe. "I've never studied a pristine sample from an asteroid," Heck said.
Medscape
24 minutes ago
- Medscape
Fast Five Quiz: Late-Onset Pompe Disease
Multiple genetic variants have been associated with LOPD. However, the c.-32-13T>G splice site variant is found in up to 90% of adults and 50% of pediatric patients. Patients with LOPD often have compound heterozygous genotypes, with one allele carrying the common c.-32-13T>G splice-site variant and the other harboring a more deleterious GAA mutation (eg, nonsense, frameshift, or large deletion). Other variants— such as and c.1935C>A — are more commonly seen in infantile forms of Pompe disease. Learn more about the pathophysiology of LOPD. Diagnosis of LOPD typically follows a two-step approach: first, measuring GAA enzyme activity (often via dried blood spot assay) followed by confirmatory molecular genetic testing to identify pathogenic GAA variants. Although once considered a first-line diagnostic tool for LOPD, muscle biopsy is no longer preferred due to its invasive nature and the non-specificity of histologic findings. Muscle biopsy may still be considered in rare, ambiguous cases when enzyme and genetic testing are inconclusive or conflicting. CK levels might be elevated in some patients but are nonspecific and primarily serve to raise clinical suspicion. Learn more about the workup for LOPD. Enzyme replacement therapy (ERT) has significantly changed the natural history of the disease by improving survival and stabilizing motor and respiratory function. However, key limitations in skeletal muscle uptake and variability in clinical response remain. This is due to low expression of the mannose-6-phosphate receptor in muscle tissue, which hampers enzyme internalization. As a result, patients might experience a limited or plateaued response. Newer approaches, including modified ERT and gene therapy, are being developed to address this issue. High toxicity to cardiac muscle, uniform patient response, and development of cardiac hypertrophy have not been reported as key limitations. Learn more about treatment options for LOPD. NBS programs have reshaped the understanding of Pompe disease, particularly LOPD. A significant proportion of screen-positive newborns harbor genetic variants associated with LOPD, including pseudo deficiency alleles and variants of uncertain significance. These individuals are often asymptomatic at birth and might not develop symptoms for years, if at all. This has raised important clinical questions around monitoring, counseling, and when (or whether) to initiate therapy; expanded screening has also revealed that the true prevalence of LOPD might be higher than historical estimates suggested. Learn more about the management of LOPD. Editor's Note: This article was created using several editorial tools, including generative AI models, as part of the process. Human review and editing of this content were performed prior to publication. Lead image: UCSF/Science Source
Yahoo
43 minutes ago
- Yahoo
A ‘dragon prince' dinosaur is redrawing the tyrannosaur family tree
Sign up for CNN's Wonder Theory science newsletter. Explore the universe with news on fascinating discoveries, scientific advancements and more. Scientists have identified a previously unknown 86 million-year-old dinosaur species that fills an early gap in the fossil record of tyrannosaurs, revealing how they evolved to become massive apex predators. Researchers analyzing the species' remains have named it Khankhuuluu mongoliensis, which translates to 'dragon prince of Mongolia,' because it was small compared with its much larger relatives such as Tyrannosaurus rex, whose name means 'the tyrant lizard king.' The newly identified dinosaur was the closest known ancestor of tyrannosaurs and likely served as a transitional species from earlier tyrannosauroid species, according to the findings published Wednesday in the journal Nature. Based on a reexamination of two partial skeletons uncovered in Mongolia's Gobi Desert in 1972 and 1973, the new study suggests that three big migrations between Asia and North America led tyrannosauroids to diversify and eventually reach a gargantuan size in the late Cretaceous Period before going extinct 66 million years ago. 'This discovery of Khankhuuluu forced us to look at the tyrannosaur family tree in a very different light,' said study coauthor Darla Zelenitsky, associate professor within the department of Earth, energy, and environment at the University of Calgary, in an email. 'Before this, there was a lot of confusion about who was related to who when it came to tyrannosaur species. What started as the discovery of a new species ended up with us rewriting the family history of tyrannosaurs.' Tyrannosaurs, known scientifically as Eutyrannosaurians, bring to mind hulking dinosaurs like Tyrannosaurus rex and Tarbosaurus, which weighed multiple metric tons and could take down equally large prey. With short arms and massive heads, they walked on two legs and boasted sharp teeth, Zelenitsky said. But tyrannosaurs didn't start out that way. They evolved from smaller dinosaurs before dominating the landscapes of North America and Asia between 85 million and 66 million years ago, the researchers said. While Tarbosaurus, an ancestor of T. rex, clocked in at between 3,000 and 6,000 kilograms (6,613 pounds and 13,227 pounds), the fleet-footed Khankhuuluu mongoliensis likely weighed only around 750 kilograms (1,653 pounds), spanned just 2 meters (6.5 feet) at the hips and 4 meters (13 feet) in length, according to the study authors. Comparing the two dinosaurs would be like putting a horse next to an elephant —Khankhuuluu would have reached T. rex's thigh in height, Zelenitsky said. 'Khankhuuluu was almost a tyrannosaur, but not quite,' Zelenitsky said. 'The snout bone was hollow rather than solid, and the bones around the eye didn't have all the horns and bumps seen in T. rex or other tyrannosaurs.' Khankhuuluu mongoliensis, or a closely related ancestor species, likely migrated from Asia to North America across a land bridge between Alaska and Siberia that connected the continents 85 million years ago, Zelenitsky said. Because of this migrant species, we now know that tyrannosaurs actually evolved first on the North American continent and remained there exclusively over the next several million years, she said. 'As the many tyrannosaur species evolved on the continent, they became larger and larger.' Due to the poor fossil record, it's unclear what transpired in Asia between 80 million to 85 million years ago, she added. While some Khankhuuluu may have remained in Asia, they were likely replaced later on by larger tyrannosaurs 79 million years ago. Meanwhile, another tyrannosaur species crossed the land bridge back to Asia 78 million years ago, resulting in the evolution of two related but very different subgroups of tyrannosaurs, Zelenitsky said. One was a gigantic, deep-snouted species, while the other known as Alioramins was slender and small. These smaller dinosaurs have been dubbed 'Pinocchio rexes' for their long, shallow snouts. Both types of tyrannosaurs were able to live in Asia and not compete with each other because the larger dinosaurs were top predators, while Alioramins were mid-level predators going after smaller prey — think cheetahs or jackals in African ecosystems today, Zelenitsky said. 'Because of their small size, Alioramins were long thought to be primitive tyrannosaurs, but we novelly show Alioramins uniquely evolved smallness as they had 'miniaturized' their bodies within a part of the tyrannosaur family tree that were all otherwise giants,' Zelenitsky said. One more migration happened as tyrannosaurs continued to evolve, and a gigantic tyrannosaur species crossed back into North America 68 million years ago, resulting in Tyrannosaurus rex, Zelenitsky said. 'The success and diversity of tyrannosaurs is thanks to a few migrations between the two continents, starting with Khankhuuluu,' she said. 'Tyrannosaurs were in the right place at the right time. They were able to take advantage of moving between continents, likely encountering open niche spaces, and quickly evolving to become large, efficient killing machines.' The new findings support previous research suggesting that Tyrannosaurus rex's direct ancestor originated in Asia and migrated to North America via a land bridge and underscore the importance of Asia in the evolutionary success of the tyrannosaur family, said Cassius Morrison, a doctoral student of paleontology at University College London. Morrison was not involved in the new research. 'The new species provides essential data and information in part of the family tree with few species, helping us to understand the evolutionary transition of tyrannosaurs from small/ medium predators to large apex predators,' Morrison wrote in an email. The study also shows that the Alioramini group, once considered distant relatives, were very close cousins of T. rex. What makes the fossils of the new species so crucial is their age — 20 million years older than T. rex, said Steve Brusatte, professor and personal chair of Palaeontology and Evolution at the University of Edinburgh. Brusatte was not involved in the new study. 'There are so few fossils from this time, and that is why these scientists describe it as 'murky,'' Brusatte said. 'It has been a frustrating gap in the record, like if you suspected something really important happened in your family history at a certain time, like a marriage that started a new branch of the family or immigration to a new country, but you had no records to document it. The tyrannosaur family tree was shaped by migration, just like so many of our human families.' With only fragments of fossils available, it's been difficult to understand the variation of tyrannosaurs as they evolved, said Thomas Carr, associate professor of biology at Carthage College in Wisconsin and director of the Carthage Institute of Paleontology. Carr was not involved in the new research. But the new study sheds light on the dinosaurs' diversity and clarifies which ones existed when — and how they overlapped with one another, he said. More samples from the fossil record will provide additional clarity, but the new work illustrates the importance of reexamining fossils collected earlier. 'We know so much more about tyrannosaurs now,' Carr said. 'A lot of these historical specimens are definitely worth their weight in gold for a second look.' When the fossils were collected half a century ago, they were only briefly described at the time, Brusatte said. 'So many of us in the paleontology community knew that these Mongolian fossils were lurking in museum drawers, waiting to be studied properly, and apt to tell their own important part of the tyrannosaur story,' he said. 'It's almost like there was a non-disclosure agreement surrounding these fossils, and it's now expired, and they can come out and tell their story.'
