Lucid dreaming describes when you realize you're in a dream as it's unfolding. Sometimes, people can control the content of their dreams from this state of awareness. Recently, researchers claimed that they found a way to "train" people to lucid dream by having them meditate and complete virtual-reality-augmented exercises while they were awake. Following the release of that study, Live Science asked its readers whether they would learn to lucid dream if they could.Over 300 readers weighed in, with 77% saying "Yes, I'd want to try to control my dreams." Additionally, 17% of respondents said "No, I already lucid dream enough without training," 3% said "No, I don't see the point," and the final 3% said they weren't sure.In the comments, one reader shared that they'd once experimented with hypnagogic napping, a technique famously used by Thomas Edison and Salvador Dalí in which the famous luminaries would wake themselves up just as they were drifting to sleep. Edison claimed that this helped him access a creative sweet spot at the edge of sleep and wakefulness."When I was experimenting with the hypnagogic state (using the Edison method) I started having spontaneous lucid dreams," the reader wrote. "I can confidently say, that there were some of the most profound experiences of my life, so the answer is definitely yes."Another reader reported having lucid dreams "about once or twice a year," adding that they typically wake up shortly after realizing it's a dream. "My most recent one was of my recently deceased wife. I became very sad when I realized she wasn't supposed to be there," the reader wrote. "I hugged her and told her I don't want to be without her. She replied that I could live a long life if I took care of myself (This was a very typical response from her...lol). I feel very blessed to have had that dream."RELATED STORIESCan you dream during non-REM sleep?Do blind people 'see' images in their dreams? Why can't we remember our dreams?Other readers chimed in on Facebook. "Already have it [lucid dreaming], but if I didn't I would certainly practice to do so," one wrote. "Hell yes," another said, in response to the idea of training themselves to lucid dream.Other readers noted that they already lucid dream quite often or that they can consistently control their dreams, with one even saying that all of their dreams are lucid. Another said, "Some nights I interrupt it [my dream] like Monty Python — 'Too silly!' and start over." But while one person compared lucid dreaming to "writing and directing your own movie," another noted that "lucid dreams can be boring, repetitive, annoying." So while many people would practice lucid dreaming if they could, not everyone sees the appeal.

Researchers compared the samples from asteroid Bennu with the Murchison meteorite and measured the amino acid β-alanine in both. Using new techniques, they were able to measure not only their isotopic compositions, but isotopic differences between individual atoms in the same molecule. The results show that some of the same pre-cursors to life formed in different conditions and positions in the protoplanetary disk.

A much greater risk factor than we ever realized.ScienceAlert stories are written, fact-checked, and edited by humans, never generated by AI. Don't miss a story, subscribe here.

Taking doxycycline, a commonly prescribed antibiotic, during the first trimester of pregnancy may increase the risk of pregnancy loss, a new study suggests.The antibiotic is broad-spectrum, meaning it targets a wide range of bacteria. It's often used to treat acne, respiratory infections and sexually transmitted infections, such as chlamydia and syphilis. Doctors generally avoid prescribing the drug during the second and third trimesters because it belongs to a class of antibiotics that can bind to calcium in developing bones. Animal studies suggest that this may disrupt fetal bone development.However, evidence on doxycycline's safety during early pregnancy has been mixed and limited. The new study, published Tuesday (Nov. 10) in the journal Annals of Internal Medicine, provides clearer evidence of a link between doxycycline use in the first trimester and pregnancy loss."I would advise physicians to carefully consider the benefit-risk balance when prescribing doxycycline to women who are pregnant or planning a pregnancy," study first author Almut Winterstein, a pharmacist and drug-safety researcher at the University of Florida, told Live Science in an email.A higher risk than other antibioticsUsing information from two U.S. insurance databases, the researchers analyzed 224,870 pregnancies in people ages 12 to 55. More than 218,230 of these patients were treated for respiratory tract infections, and over 6,630 were treated for acne, between conception and the end of the first trimester. About 4,385 of the women filled a prescription for doxycycline during that time frame, while the others received an alternative antibiotic.Among women with respiratory infections, those prescribed doxycycline had a 40% to 54% higher risk of pregnancy loss, compared with those prescribed amoxicillin, another broad-spectrum antibiotic in a different class. The exact level of risk varied between the two databases. The researchers also compared the doxycycline users against women prescribed macrolides, the class of antibiotics that includes azithromycin (or "Z-Pak"). Again, the doxycycline users saw a higher risk — 39% and 36% higher, respectively.Among the patients treated for acne, doxycycline users had a 49% higher risk of pregnancy loss in one database than those given the antibiotic clindamycin. In the second database, though, the difference wasn't statistically significant. Winterstein said that may be because there were fewer patients included in that analysis.Overall, doxycycline was associated with seven to 11 additional pregnancy losses per 100 pregnancies, compared with the other antibiotic options assessed, the researchers reported.The researchers examined the risk associated with taking various antibiotics in the first 12 weeks of pregnancy. (Image credit: MementoJpeg via Getty Images)What drives the risk?It is not yet clear how the drug might contribute to pregnancy loss. Because the study was observational, it cannot prove that the antibiotic itself caused those losses, which included miscarriages and stillbirths. (Miscarriage is pregnancy loss before 20 weeks of pregnancy, whereas stillbirth refers to pregnancy loss after the 20th week.)Animal studies hint that doxycycline could interfere with early placental development, potentially making it harder for the placenta to support a growing pregnancy, Luke Grzeskowiak, an associate professor and clinical pharmacist at Flinders University in Australia who was not involved in the study, said in an email. The study authors also noted in their report that the drug may have direct effects on the developing embryo. But these explanations remain hypothetical; the researchers have not established that either mechanism occurs in humans."Pregnancy loss affects around one in four pregnancies and can happen for many reasons," Grzeskowiak noted. Although doxycycline exposure may add to that risk, taking the antibiotic does not necessarily mean pregnancy loss will occur. The available data suggests that it is just one risk factor among many.RELATED STORIESCould an antibiotic taken after unprotected sex prevent STIs? What to know about doxy-PEP.'They didn't question it': Why doctors prescribe too many antibioticsMini-brains show how common drug freezes cell division in the womb, causing birth defectsBecause doxycycline may be prescribed before a pregnancy is recognized, doctors should consider the possibility of pregnancy when prescribing this drug to women of reproductive age, particularly those who are sexually active, Grzeskowiak suggested. That does not mean doctors should avoid prescribing the antibiotic to these women, he emphasized; rather, clinicians should consider pregnancy plans and medical history when choosing a treatment. In some cases, doxycycline may still be the best option for a severe infection, Winterstein told Live Science, and that infection could itself put a pregnancy at risk. But for less-serious infections, safer alternatives may be available, she said.This article is for informational purposes only and is not meant to offer medical advice.

Archaeologists have found what may be the world's oldest poisoned weapons at a 125,000-year-old site on an ancient lakeshore in Saudi Arabia. The stone tools, which were likely used to hunt large animals, had traces of residue from a poisonous tree historically used for its toxins."At 125,000 years old, these would be substantially older than the poisoned arrowheads recently identified in South Africa, which date to around 60,000 years ago," study co-author Chris Clarkson, an archaeologist at the Max Planck Institute of Geoanthropology in Germany and Griffith University in Australia, told Live Science in an email. "But we haven't demonstrated exactly how the poison was prepared or whether it was effective. So I'd describe these as potentially the oldest evidence for poisoned hunting weapons, rather than an unequivocally established first."In the new study, published Thursday (Nov. 12) in the journal Science, researchers investigated a 125,000-year-old site in southern Saudi Arabia known as 'Uruq Aljelibah, which means "sand dunes of a watering hole," study co-author Frans van Buchem, a geologist at the King Abdullah University of Science and Technology in Saudi Arabia, told Live Science. Today, the area is "hot, extremely dry, with extensive sand dunes," Clarkson said, located as it is within the Empty Quarter — one of the hottest, driest deserts on Earth. But the scientists found the site was once home to a freshwater lake measuring about 130 square miles (340 square kilometers) and up to 95 feet (29 meters) deep. Fossils there suggest it once supported a rich diversity of flora and fauna, including hippopotamuses, buffalo, ostriches, camels, gazelles, oryx, palms, reeds, trees and shrubs, which early modern humans likely exploited for food and other resources."The idea of hippopotamuses and enormous buffalo living around a lake in what is now the Empty Quarter really brings home just how dramatically these landscapes, and global climates, have changed," Clarkson said.Saudi Arabia is a desert today, but it used to be a lush landscape. (Image credit: Christopher Clarkson / Griffith University)Astonishing stone toolsThe archaeologists discovered more than 5,500 stone artifacts at the site, along with extraordinarily preserved traces of plant materials, such as fibers, resins and wood. Several of these artifacts were stone points that showed impact damage consistent with hunting large animals, and a microscopic analysis revealed traces of animal tissue near the point tips. The distribution of the stone tools closely matched clusters of animal bones, suggesting that the lakeshore was a focal point for hunting and processing game, according to the study."At most Paleolithic sites, we're lucky if we get the stone tools and perhaps a few animal bones," Clarkson said. "Here we can actually begin to reconstruct what those tools were doing and what other materials people were combining with them."The researchers found that people may have hunted animals with poison-tipped tools. Several stone points had chemical residues linked with the arrow poison tree (Acokanthera schimperi), which is known historically for its toxins and is native to eastern and central Africa and southern Arabia. African hunters have coated spear tips and arrowheads with extracts from this plant to paralyze or kill game.It remains unclear how hunters who poisoned their targets might have avoided poisoning themselves upon eating the game. "The effects of a poison depend on the substance, the dose and how it enters the body," Clarkson said. "A poison introduced directly into a wound doesn't necessarily behave in the same way when swallowed." Hunters throughout history "are known to sometimes remove the meat around the wound before eating the rest of the animal," he added.These findings emphasize how researchers have often underestimated the technological complexity of early human populations, because so much of what they made was organic and has simply disappeared," Clarkson said. "These weren't just people knocking stone flakes off cores," Clarkson noted. "They were combining stone with wood, plant fibers, resins and potentially toxic substances to make complex tools and weapons."To have so much evidence for how people were making and using tools in a site like this "is remarkable," Eleanor Scerri, an archaeologist at the Max Planck Institute of Geoanthropology in Germany who did not take part in this research, told Live Science in an email. "This goes from both the micro-scale, in finding traces of how people hafted spear tips, for instance, up to the bigger scale of the whole site and the very convincing spatial relationship between hunting-related tools and the bones of animals such as hippos."Sites in Arabia that possess both stone tools and animal bones are rare, Jeffrey Rose, a Paleolithic archaeologist at the University of Algarve in Portugal who did not participate in this study, told Live Science in an email. "This one has thousands of artifacts on an old lakeshore alongside hippo, buffalo and ostrich, and some of the flakes fit back together, so the tools were made on the spot," he said. "It's valuable new data."Out of AfricaThe Arabian Peninsula sits between Africa and the rest of Asia and was a major corridor for humans as they dispersed across the world. Recurring spans of increased rainfall could have made its otherwise hostile landscapes more habitable in the past. However, the hot desert that now covers much of Arabia has made it difficult for scientists to excavate many details about this vital bridge during this critical point in human history.The researchers did not unearth any human remains. Still, they suspect the site most likely belonged to modern humans (our species, Homo sapiens), as opposed to a different human species."We know that H. sapiens had already expanded out of Africa and were present in Southwest Asia during this period," Clarkson said. "The age of the site fits with those early movements."These findings add to growing evidence that wetter intervals in Arabia created migration corridors between Africa and Asia and supported productive habitats capable of sustaining repeated human occupation. "What our site shows is that people weren't necessarily just passing through these environments," Clarkson said. "They were exploiting them in quite sophisticated ways, using a range of technologies and resources."But Rose cautioned that all of the stone artifacts found in this study were collected from the surface. "Not one was excavated from the layers that were dated," he said. "The 125,000-year date belongs to the lake, not to the tools. For the tools, it is only a maximum age." Future research at the site should look for stone artifacts sealed in lake beds. "That's hard in Arabia, where wind has stripped most sites down to surface scatters, but it can be done," Rose said.RELATED STORIESNeanderthals may have trekked through the Saudi Arabian desert 55,000 years ago, farther south than experts thought possible1,200-year-old gold hoard discovered in Saudi Arabia may have been buried by a medieval pilgrimLife-size rock art points the way to oldest human inhabitants of Saudi Arabia — and the desert oases they usedClarkson agrees that further work is needed. "I'd really like to keep going back to this site to find more fossils, both animals as well as hopefully human fossils," Clarkson said. "I'd also really like to push the chemical and functional analyses further, particularly the evidence for toxic plant compounds. It would be fascinating to determine exactly which substances were being used, how they might have been prepared and whether they were deliberately applied to hunting weapons."Future research focusing on the ancient lake margins may reveal more information. "There must be other places where people were living and carrying out activities, and some may preserve better stratified archaeological deposits," Clarkson said.But the combination of discoveries at this site is amazing, the researchers said. "I've spent much of my career studying stone tools, and one of the great frustrations is that we're usually only looking at the small fraction of ancient technology that survives," Clarkson said. "Here we have a chance to see much more of the complete technological system."