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Archaeologists in the United Kingdom say they have uncovered evidence of a much earlier and simpler version of Stonehenge located about 3 miles (5km) from the world-famous prehistoric monument. Researchers believe the site, found in Bulford, once consisted of just two wooden posts placed in the ground. Although the timber has long decayed, the remaining post holes suggest the structure was carefully aligned with the Sun during the summer and winter solstices, similar to Stonehenge. The site has been dated to around 5,000 years ago, making it about 500 years older than Stonehenge itself. Excavations at the location also uncovered pottery fragments, flint tools and animal bones, indicating that prehistoric communities may have gathered there for rituals or seasonal events. Phil Harding of Wessex Archaeology, who led the excavation, described the discovery as one of the most significant of his career. “Two post pits tell me much more about the people 5,000 years ago,” he said. “It shows how they thought, behaved and how they observed the sky.” Stonehenge is well known for its precise alignment with the Sun. During the summer solstice, the sunrise appears over the Heel Stone to the northeast of the monument, while at midwinter the sunset aligns with the central structure to the southwest. The newly discovered site appears to have followed a similar solar alignment, despite being far simpler in design. The two wooden posts are believed to have stood around 120 metres apart and may have been 2 to 4 metres tall. Harding said the alignment became clear when he studied the layout. “I got my pencil and ruler and joined them up, and I realised they were pointing in the direction of the midsummer sunrise,” he said. The remains were originally discovered about a decade ago during land clearance for military housing in Bulford, but only recent analysis confirmed their astronomical alignment. Experts say reconstructing the ancient sky was key to understanding the site. Dr Fabio Silva, an archaeoastronomer, said the position of the Sun and stars changes gradually over thousands of years, requiring scientists to recreate how the sky looked 5,000 years ago. “When you factor in the width of the posts, the alignment is exact for the summer solstice sunrise and winter solstice sunset,” he said.   Researchers believe the Bulford site dates to the earliest phase of Stonehenge construction, before the famous stone circle was built. Dr Jennifer Wexler of English Heritage said the discovery could suggest that early builders of Stonehenge may have lived nearby or gathered seasonally in the area. Experts also say the findings highlight the importance of the Sun in the lives of early farming communities, who depended heavily on seasonal cycles for agriculture. Today, Stonehenge is a major attraction during the summer solstice, drawing thousands of visitors to witness the sunrise. But researchers say the winter solstice may have held even greater significance for ancient people, marking the end of the dark season and the return of light and new growth. Source: BBC  

The three astronauts aboard China's Shenzhou-23 mission have completed their first in-orbit medical rescue training since arriving at the Tiangong space station, according to a video released by the China Manned Space Agency (CMSA). The training was designed to help astronauts Zhu Yangzhu, Zhang Zhiyuan and Li Jiaying become familiar with rescue operation techniques and the characteristics of force application in a microgravity environment, the CMSA said in the video released on Sunday. Apart from the medical rescue exercise, the crew has been carrying out a variety of scientific experiments. Using a space Raman spectrometer, they studied the relationship between gut microbiota and nutritional metabolism during long-duration space missions. The astronauts also conducted behavioral experiments on visual motion processing and intuitive physics under microgravity conditions to examine the effects of gravity on visual information processing and the impact of prolonged spaceflight on intuitive physics perception. In addition, the crew carried out in-orbit assessments of emotion recognition and emergency decision-making capabilities. China launched the Shenzhou-23 crewed spacecraft on May 24. The mission includes a one-year in-orbit stay experiment, expected to provide important data for future long-duration space exploration missions.

People across the Northern Hemisphere are experiencing the longest day of the year on Sunday as the summer solstice marks the beginning of astronomical summer. The event also signals the start of winter in the Southern Hemisphere, where Sunday is the shortest day and longest night of the year. The term "solstice" originates from the Latin words sol, meaning sun, and stitium, meaning pause or stop. The summer solstice occurs when the sun reaches its highest and longest path across the sky before beginning its gradual retreat, causing daylight hours to shorten each day until late December. For centuries, cultures around the world have marked the solstice with celebrations and monuments, including Sweden's midsummer festivities and the ancient stone circle of Stonehenge, which was designed to align with the sun's position during the solstices. The phenomenon is caused by the Earth's tilted axis as it orbits the sun. Because the planet is tilted, sunlight and warmth are distributed unevenly between the Northern and Southern hemispheres throughout most of the year. The solstices occur when the Earth is tilted at its maximum angle either toward or away from the sun, resulting in the greatest differences in the length of day and night. During the Northern Hemisphere's summer solstice, the upper half of the Earth is tilted toward the sun, producing the longest day and shortest night of the year. The summer solstice typically falls between June 20 and 22. Conversely, the Northern Hemisphere's winter solstice occurs between December 20 and 23, when the region is tilted furthest away from the sun, leading to the year's shortest day and longest night. The solstice differs from the equinox, which occurs when the Earth's tilt is neither toward nor away from the sun. During an equinox, both hemispheres receive nearly equal amounts of sunlight, resulting in day and night lasting almost the same length. The word "equinox" is derived from Latin terms meaning "equal" and "night." The Northern Hemisphere experiences the autumnal equinox between September 21 and 24 and the vernal, or spring, equinox between March 19 and 21. Scientists also distinguish between astronomical and meteorological seasons. Astronomical seasons are based on the Earth's position in relation to the sun, while meteorological seasons are determined by annual temperature patterns and divide the year into three-month periods. Under the meteorological calendar, summer begins on June 1, autumn on September 1, winter on December 1 and spring on March 1.

Scientists have discovered the earliest known evidence of plague, showing that deadly outbreaks occurred around 5,500 years ago -  about two centuries earlier than previously believed. The disease has affected humans for thousands of years and killed millions, including a large portion of Europe’s population during the 14th-century Black Death. Although rare today, plague still exists and can be treated with antibiotics. Deep sleep found key to muscle growth, fat burning and brain function Researchers led by evolutionary geneticist Eske Willerslev of the University of Copenhagen examined remains from four cemeteries near Siberia’s Lake Baikal and found traces of plague-causing bacteria in the teeth of 18 ancient hunter-gatherers. Carbon dating of the remains showed that the disease caused at least two outbreaks, with the earliest cases appearing about 5,500 years ago. Scientists said the prehistoric plague evolved gradually and likely spread from marmots through consumption of raw organs or contact with infected hides. It could also pass between humans through coughing and sneezing. Many victims were children aged between 8 and 11. Researchers found several related individuals buried together, including three girls and an aunt and nephew. The study, published in the journal Nature, suggests ancient plague affected both small nomadic communities and larger populations. Scientists said understanding its evolution may help explain how dangerous pathogens emerge in the future.

Scientists have developed a new genetic analysis method that uses “time stamps” hidden in DNA to trace the complex origins of the cultivated strawberry, revealing a far more complicated evolutionary history than previously understood. Many major crops, including strawberry, wheat and cotton, have highly complex genomes formed through repeated hybridization and whole-genome duplication. These plants carry multiple sets of chromosomes from different ancestral species, making it difficult for scientists to reconstruct their exact origins, especially when some ancestor species are extinct or unknown. A new study published in the journal *Horticulture Research* presents a genome-wide approach that helps untangle these complicated histories. The method analyzes patterns in long terminal repeat retrotransposons, a type of mobile DNA that leaves behind evolutionary signatures over time. By comparing similarities in these genetic elements across chromosomes, researchers can separate different ancestral genome groups and estimate when key genome-merging events took place. When applied to the cultivated octoploid strawberry the approach revealed that its genome was formed through multiple rounds of ancient hybridization events. The analysis identified four distinct subgenomes and suggested that three major genome-merging events occurred between about 3.1 and 0.8 million years ago. The findings also support links between parts of the strawberry genome and two wild species, ‘Fragaria vesca’ and ‘Fragaria iinumae’, while challenging earlier theories that suggested additional unknown ancestor species. Researchers say some of the missing contributors may be extinct or have not yet been identified. Before testing the method on strawberry, scientists validated it using other well-studied crops such as teff and cotton, where it successfully separated known subgenomes and reconstructed their evolutionary timelines. Researchers say the approach could have broad applications for other important polyploid crops. Better understanding of subgenomes may improve gene mapping, trait identification and plant breeding strategies, potentially helping to develop stronger and more productive crop varieties. The study highlights how mobile DNA elements can act as evolutionary markers, allowing scientists to reconstruct genome history even without direct access to ancestral species. Source: Daily Science

Scientists have identified a brain mechanism that links deep sleep with growth hormone release, helping explain how quality sleep supports muscle growth, fat metabolism and brain function. Researchers at the University of California, Berkeley, say the discovery sheds new light on why poor sleep can affect physical health and may eventually help develop treatments for sleep-related metabolic and neurological disorders. Deep sleep, particularly the non-REM stage, plays a crucial role in repairing the body, strengthening muscles, supporting bone growth and regulating fat storage. It is also important for normal growth during adolescence. Growth hormone, which is released mainly during sleep, is central to these processes. However, scientists have long been uncertain about exactly how sleep controls the hormone's release. In a study published in the journal ‘Cell’, researchers mapped brain circuits involved in growth hormone regulation and discovered a feedback system that helps maintain a balance between sleep and hormone production. “People know that growth hormone release is tightly related to sleep,” said lead author Xinlu Ding. “We are providing a basic circuit to work on in the future to develop different treatments.” The study found that specialised cells in the hypothalamus, a region deep within the brain, control growth hormone through two key chemical signals. One stimulates hormone release while the other suppresses it, allowing the body to regulate hormone levels throughout different stages of sleep. Researchers also found that once growth hormone is released, it activates another brain region called the locus coeruleus, which is involved in alertness, attention and thinking ability. According to the study, hormone levels rise differently during REM and non-REM sleep, helping maintain healthy body functions. The team also discovered a feedback loop in which growth hormone gradually promotes wakefulness as sleep continues. However, excessive activity in the same brain region can trigger sleepiness, creating a balance between sleep and alertness. “This balance is essential for growth, repair and metabolic health,” said study co-author Daniel Silverman. Scientists say the findings could have implications for conditions linked to poor sleep, including obesity, diabetes, heart disease, Parkinson’s disease and Alzheimer’s disease. Researchers also noted that growth hormone may benefit cognitive performance by supporting alertness and mental focus after waking up. “Growth hormone not only helps you build your muscle and bones and reduce your fat tissue, but may also have cognitive benefits,” Ding said. The study was conducted by researchers from UC Berkeley and Stanford University and was supported by the Howard Hughes Medical Institute and other research grants. Source: Science Daily

How children respond to simple facial expressions such as smiles and frowns may provide early clues about their risk of developing depression, according to a new study by researchers at Binghamton University. The research found that depression can affect the way children pay attention to emotional faces, and these patterns differ depending on whether they have a family history of depression. Researchers at Binghamton University's Mood Disorders Institute are studying how depression develops during childhood and adolescence. They hope that identifying early warning signs could help doctors and families detect and address mental health problems before they become more serious. “Many of the risk factors we study are still developing during childhood,” said Brandon Gibb. “This gives us a chance to identify problems early rather than waiting until they become more established.” Previous studies have shown that people with depression often pay more attention to sad facial expressions. However, scientists have long debated whether this attention pattern causes depression or is a result of it. The new study is the first to examine how depressive symptoms and attention to emotional faces may influence each other over time in children. Lead researcher Kelly Gair said the study explored how attention patterns and depressive symptoms continuously affect one another as children grow. The research followed 242 children and their mothers over a two-year period. Participants were assessed every six months. During each assessment, children were shown pairs of faces on a screen. One face displayed a neutral expression, while the other showed a happy, sad or angry expression. Researchers used eye-tracking technology to measure which faces attracted the children's attention and how long they looked at them. The findings revealed different patterns based on family history. Among children whose mothers had experienced major depression, increasing depressive symptoms were linked to greater attention to sad faces. Researchers said that as these children became more depressed, they appeared to have greater difficulty shifting their attention away from negative emotional cues. Gibb suggested that children exposed to more sadness at home may become especially sensitive to sad facial expressions when they experience depressive symptoms themselves. For children whose mothers had no history of depression, the pattern was different. Instead of focusing more on sad faces, they spent less time looking at happy faces when their depressive symptoms increased. Researchers believe this may reflect the loss of a protective factor, as attention to positive emotions could help buffer against depression. The team is continuing to follow the children as they enter adolescence to determine whether these attention patterns increase the likelihood of developing clinical depression later in life. The findings were published in the scientific journal Journal of Psychopathology and Clinical Science. Researchers say the study could help improve early detection and prevention efforts by identifying subtle behavioural signs that emerge before depression becomes severe. Source:Science Daily

Chinese scientists have identified a major cause behind the early developmental failure of human embryos, a breakthrough that could improve the success rate of in vitro fertilization (IVF) treatments in the future. The findings, published in the journal 'Cell', come from a study led by researchers at Tsinghua University, who captured the first high-resolution images of human embryos during the first five days after fertilization. Many couples undergoing IVF face disappointment as more than half of fertilized eggs fail to develop into blastocysts, the stage at which embryos are ready to be implanted in the uterus. The reasons behind this high failure rate have long remained unclear. To investigate, researchers developed a new imaging tool called a dual-view light-sheet microscope. The technology allowed them to observe living embryos for extended periods without causing damage. The team analyzed more than 2,000 cell divisions in over 150 human and monkey embryos. They found that more than 70 percent of embryos that stopped developing experienced problems during their second cell division. According to the researchers, the issue was linked to abnormalities in a cellular structure known as the spindle, which helps distribute genetic material evenly when cells divide. Defects in the spindle led to chromosome separation errors, causing embryo development to halt within a few cell divisions. The study also revealed that centrosomes, cell structures responsible for organizing the spindle, play a critical role. When embryos had an abnormal number of centrosomes, the spindle could not function properly, increasing the risk of developmental failure. Building on this discovery, the researchers tested a low dose of a drug designed to regulate centrosome replication during the second cell division. The treatment significantly improved embryo quality, increasing the proportion of embryos with normal centrosomes from 40 percent to 80 percent. Importantly, the drug did not affect embryos that already had normal centrosomes, suggesting it may offer a targeted way to reduce developmental errors. Chun So, an assistant professor at Tsinghua University, said the findings could eventually help IVF clinics reduce cases of early embryo arrest and improve pregnancy outcomes. He added that the research team plans to continue developing advanced imaging technologies to better understand human embryo development after implantation, with the goal of finding new ways to increase the chances of successful pregnancies.

Honey bees are much more skilled at navigation than previously believed, with new research showing that individual bees follow their own preferred flight routes and repeat them with impressive precision using landmarks in the environment. Researchers at the University of Freiburg tracked honey bees flying between their hive and a food source about 120 metres away and found that each bee consistently used nearly the same path on every trip. The study was led by Andrew Straw, whose team used a drone-based tracking system to observe the insects in a natural agricultural setting. To monitor the bees, researchers attached tiny reflective markers to them and used a technology called Fast Lock-On (FLO) Tracking. The system enabled the drone to identify and follow individual bees within milliseconds, allowing scientists to record highly detailed three-dimensional flight paths. The findings showed that each bee preferred a specific route and was able to follow it with exceptional accuracy while travelling both to and from the food source. “Our recordings show that each bee has its own preferred route and flies it very precisely,” Straw said, adding that the behaviour is so distinct that “each bee has its own personality.” The research team analysed 255 flight paths near the Kaiserstuhl region. The study area included hedges, a cornfield and a large tree located between the hive and the feeding site, forcing bees to take indirect routes. Scientists found that bees often flew only a few centimetres away from their previous paths, demonstrating a surprisingly high level of consistency. The most accurate navigation occurred near noticeable landmarks, particularly the tree. In contrast, bees showed greater variation when flying over the cornfield, where the landscape offered fewer visual references. According to the researchers, the findings suggest that honey bees rely heavily on visual landmarks to guide their journeys and improve navigation accuracy. The study also offers new insights into the famous “waggle dance,” the method honey bees use to communicate the location of food sources to other members of the colony. Previous studies showed that the directional information shared through the waggle dance is not always highly accurate and can vary by about 30 degrees for food sources located around 100 metres away. However, the new research indicates that this imprecision is not due to poor navigation skills. Researchers found that bees travelling to locations they already know can stay extremely close to their established routes, deviating by only a few degrees even in areas where flight paths vary the most. The findings suggest that honey bees possess much stronger navigational abilities than their dance communication alone would indicate, making them among nature’s most precise insect navigators. Source: Science Daily

Parrots may do more than simply mimic human speech. A new study suggests the birds could be using names to identify specific people, animals and even themselves, much like humans do in everyday communication. The research, published in the journal PLOS ONE, examined hundreds of recordings of captive parrots and found evidence that some birds use names in meaningful ways rather than just repeating words they hear. The study was led by Lauryn Benedict of the University of Northern Colorado, working with longtime collaborator Christine Dahlin and researchers from Austria. Instead of studying parrots in the wild, the team focused on pet parrots living alongside humans. These birds are regularly exposed to human conversations and often hear names being used in daily life. Using data from the ManyParrots Project, researchers analyzed survey responses and audio recordings from more than 880 parrots. Nearly half of the participants provided examples of parrots saying names. Among 413 recordings containing names, researchers identified 88 cases in which birds appeared to use names to refer to specific people or animals. The findings suggest that some parrots associate particular names with individual people rather than using them as general labels for all humans. Researchers say names play an important role in helping humans manage social relationships, and some animals may use similar vocal signals to recognize or address one another. However, Dahlin cautioned that scientists cannot yet say parrot naming behavior is the same as human naming systems because the intentions behind animal communication remain unclear. The recordings also showed that parrots use names in different ways. Some birds repeatedly said their own names to attract attention, indicating that names may serve various social purposes depending on the situation. According to the researchers, the study suggests parrots have both the mental ability and vocal skills needed to use names flexibly. In some cases, they may even refer to individuals who are not present at the time. The findings add to growing evidence that parrots possess sophisticated communication abilities, while also highlighting how much scientists still have to learn about how animals use sounds to identify and communicate about one another.The researchers say further studies are needed to better understand when and why parrots and other animals use name-like vocal signals. Source: Science Daily