Junior salaries have been in free fall for years. New study suggests the impact of AI is not so obvious

We have been seeing headlines for a couple of years about the destruction that AI is doing to employment junior. And the usual reply: no, it’s an excuse, that companies cut when rates rise and AI is only a convenient justification. Both readings are partly right. That’s just the problem. The study. The Stanford Digital Economy Lab has been analyzing actual payrolls. Not surveys or estimates: payrolls. Published a study at the end of 2025 but keeps updated dashboard with much more recent data. The result. Employment of those aged 22 to 25 in professions highly exposed to AI has fallen since the end of 2022, just when ChatGPT arrived, and lately at a rate of 4% annually. In those over 30, in those same professions, it increases. Coinbase charged 14% of its workforce citing AI as the cause. Salesforce stopped hiring juniors last year. The nuance. The same study adds a very interesting nuance: the effect does not appear when the AI ​​helps someone do their job, but when it does it for them. Write code, answer ticketswrite a first draft: that’s where hiring goes down. Review, verify, support a decision: it remains there. It does not replace human work in general. It replaces the boring job you start with when you are a youngster. It’s time to stop and agree with those who disagree.. In 2001, relocation to India was blamed for a slowdown that actually came from interest rates: when rates fell, hiring returned, and the debate about India remained unresolved. The OECD points in the same direction in your report this month: Unemployment among young graduates was already rising before ChatGPT existed. Coexistence? The two things may coexist. But even if only part of the fall is done by the AI, that part attacks the step that no one else can replace. The intern who answers wrong tickets for six months or do well needing help you’re not wasting your time: you’re learning to fail cheaply in a controlled environment. Removing that step doesn’t fire anyone today. In ten years there will be a lack of people senior and no one will be able to explain why, because by then they will have forgotten that the bottom step disappeared long ago. Featured image | Xataka In Xataka | Spanish companies systematically hide their salary in job offers: there are notable exceptions

Science suggests that we are ignoring ultradian rhythms

We have been hearing about the circadian rhythmsand we know well that the blue light from screens before sleeping is bad or that the melatonin sends at night to induce sleep. However, there is a second biological clock that is much less talked about, but which dictates exactly why at 11:30 in the morning we feel invincible, but when 1:00 p.m. arrives we cannot keep our eyes open to work. These are the ultradian rhythms. Its foundation. Far from being an invention of productivity gurus, the existence of these rhythms is deeply rooted in our physiology and hormonal secretionespecially during sleep. But the important thing is that understanding them will not give us superpowers, but according to scientific and neurobiological literature, it does explain how the brain “battery” works. What are they? To understand ultradian rhythms, we must travel to the 1950s and focus on Nathaniel Kleitman, the pioneering researcher who discovered REM sleep. At this point, Kleitman and his team realized that we don’t sleep in one uniform stretch, but rather our night is divided into cycles that last between 90 and 120 minutes. During each cycle, we go through several stages, such as light sleep, deep sleep and also REM sleep. Once we reach this we start again, and this is what is known as the ultradian rhythm. It is maintained. Logic could make us think that this cycle remains only in sleep, but here Kleitman postulated the Basic Rest-Activity Cycle (BRAC). With this theory on the table, it was proposed that this same 90-minute clock does not turn off when we wake up, but rather that during the day our brain continues to operate in waves. In this way, we can see that we have peaks of high alertness and concentration of about 90 minutes, followed by valleys of fatigue of about 20 minutes where the body requires a rest to recover. A hormonal issue. Something that is well known is that the secretion of hormones is not done continuously like an open tap, but in pulses or “peaks” that are synchronized with these 90-minute cycles. For example, growth hormone is essential to repair our tissues and its maximum peak is linked to the stages of deep sleep that occur in the first ultradian cycles of the night. This means that, if these first 90-180 minutes of sleep are disturbed, the body will not repair itself in the same way. Respect the ultradian rhythm. Among the tips we can follow to control these cycles is the 90/20 rule at work. And if we assume Kleitman’s BRAC cycle, the optimal window of mindfulness lasts about 90 minutes and then we enter a moment of fatigue where we do not perform in the same way. That is why it may be best to work for 90 minutes and then take a real break away from the work screen, for 15-20 minutes to reset this cycle. But the moment of waking up is also essential, since feeling tired when getting out of bed usually occurs because the alarm went off in the middle of the slow wave sleep phase or deep sleep. That is why calculating the hours of sleep in blocks of 90 minutes increases the probability that we will wake up at the end of these cycles and be able to get up with much more energy. Images | Vitaly Gariev In Xataka | Neither red light makes you sleepy, nor white noise is magic: what science says about the trend of “hacking” the bedroom

We believed that pets were replacing children. One study suggests just the opposite

The first time I saw a dog in a stroller It was in a shopping center. It passed me like any child’s stroller: wheels, hood, a small package inside. I looked twice because it seemed too small for a baby, and it wasn’t. Inside there was a dog. I remember well that he was a french bulldog and her name was Chanel. Over time, the scene stopped seeming exceptional to me. I started seeing dog strollers in downtown neighborhoods, parks or even on public transportation. An image that has become a symbol of something deeper: the feeling that, in aging societies, pets are occupying a place that children once had. But what if that reading was incomplete, or outright wrong? What if, far from replacing children, pets were playing another role in family life? An academic study questioned a widely held belief a few months ago. To begin with, the numbers help to understand why suspicion has established itself in the public debate. In Spain, according to the Spanish Network for the Identification of Pet Animals (REIAC)in 2023 there were more than ten million dogs registered compared to less than two million children between 0 and 4 years old. A difference so wide that it invites, almost automatically, to think about a change within homes. The scenes that come from outside reinforce that impression. South Korea has crossed a symbolic threshold: More strollers are sold for dogs than for babies. It is not an exaggeration, it is the statistical reflection of a country in demographic emergency. The trend has caught on so much that even faith has adapted. In Japanese temples such as Ichigaya Kamegaoka, the ancient ritual of Shichi-Go-San —previously exclusive for children— has filled with snouts and straps. In the absence of infants, sanctuaries bless pets to prevent their liturgies from being left without protagonists. Against this backdrop, political and moral interpretations have proliferated. In 2022, Pope Francis described as “selfish” to those who prefer to have animals rather than children. In South Korea, then Labor Minister Kim Moon-soo He even stated that young people They “love their dogs” instead of starting families. A resounding diagnosis that, until now, had relied more on cultural symbols and perceptions than on contrasted data. Disassembling the narratio But the idea that pets replace children received a serious corrective from academic research. The study Cats, Dogs, and Babiesled by researchers Kuan-Ming Chen and Ming-Jen Lin from National Taiwan University, analyzed for more than a decade the behavior of millions of homes. The research concluded that people who adopt a dog are up to 33% more likely to have a child later than those who do not. Far from displacing paternity, the animal seems to act as a preliminary step. This is what the authors call the “practice child effect”. As Chen and Lin explainmany couples use the experience of caring for a dog to evaluate their willingness to take on responsibilities: routines, expenses, and emotional bonds. If the experience is positive, it increases confidence to take the next step towards human parenthood. However, there is no change in sight. Neither the Taiwanese study nor the experts who analyze the demographic winter maintain that the increase in pets will translate, by itself, into a rebound in birth rates. The academic work itself warns that this is a country-specific analysis and that patterns may vary depending on the cultural, economic and social context. Furthermore, it is not yet a peer-reviewed article to verify the data either. The cart as a metaphor The study does not propose pets as response to demographic declinebut as a clue about how care decisions are postponed today in a context of economic and vital uncertainty. This reading fits with what sociologists and demographers point out in Spain. As reflected in the analysis of my colleague in Xatakathe drop in the birth rate responds to widely documented structural factors: job insecurity, rising housing costs, difficulties in conciliation, delay in emancipation and increasingly later motherhood. In this scenario, pets do not displace children; They occupy the space left by a postponed vital project. For this reason, the image of the dog in a stroller summarizes this ambiguity well. As Dr. Jerry Klein explainschief veterinarian of the American Kennel Club, these strollers can have a practical function in certain cases: “They offer elderly dogs, dogs with arthritis or mobility problems a way to enjoy the outdoors without straining themselves.” Veterinary platforms such as Dialvet either ToeGrips They agree that they can help protect paws from hot asphalt or help small dogs who cannot keep up with long walks. However, other experts urge caution. Carlos Carrasco, from DOS Training, warns in La Voz de Galicia that “a dog is not a child with hair” and that carrying a healthy animal in a stroller can be a “humiliation” that denaturalizes it. Along the same lines, ethologist Isabel Jiménez, director of La Manada de Iris, points out in IM Veterinaria that excessive humanization “nullifies the dog as a species and makes it emotionally ill.” a study published in Animals (MDPI) reinforces this idea, warning that anthropomorphism can generate anxiety and stress in the animal by not respecting its basic biological needs, such as smelling and walking. Finally, the rise of pets does not alone explain the demographic winter, but it does reveal how forms of affection and responsibility are reconfigured in societies where having children has become more complex. The Taiwanese study does not offer miracle solutionsbut there is a clear warning: facing pets and children as if they were exclusive options oversimplifies a much more nuanced reality. Perhaps, when we see a dog in a stroller, we are not looking at the symbol of renunciation, but rather at the reflection of a generation that postpones irreversible decisions while looking for possible forms of care. Before blaming the puppies, it might be worth looking at the system surrounding those who are hesitant to become parents. Image | Unsplash Xataka | As Japan runs out … Read more

Science now suggests that it also improves mood (even decaffeinated)

For many of us, life doesn’t begin until we drink our first cup of coffee in the morning to receive the morning rush that we directly associate with the power of caffeine. But the reality is that this is not the culprit, but rather the coffee itself (even without caffeine) and its interaction with the microbiota It is our digestive system that is truly responsible for our high. What has been seen? A recent and exhaustive study published in the prestigious magazine Nature has shown than regular coffee consumption drastically modifies our intestinal microbiomewhich is increasingly beginning to have more relevance. And, through the well-known gut-brain axis, which can be imagined as a highway that connects both places, this drink is capable of improving our mood and reducing stress. An experiment. To reach this result, the research team recruited 31 regular coffee drinkers, who consumed between 3 and 5 cups a day. But at the same time they also needed 31 people not to drink any coffee. From here, regular consumers were subjected to what was probably the worst fortnight of their lives: two weeks without drinking any coffee. The good news is that, after this period, the drink was reintroducedbut in a controlled way, separating the subjects between those who drank normal coffee and those who drank decaffeinated coffee. The result. Through stool and blood analysis, along with psychological and cognitive tests, it was possible to see that when coffee was reintroduced, markers of perceived stress plummeted and mood improved. And since decaf achieved the same psychological impact, the researchers concluded that what is responsible for making us feel good is not (only) caffeine, but the bioactive compounds in coffee feeding our bacteria. Because? When we are drinking coffee, the reality is that we drink a powerful cocktail of polyphenols and chlorogenic acids that act as prebiotics, making them perfect food for certain beneficial bacteria that live in our colon. Here the study detected that coffee promotes the growth of some specific species such as Eggertella sp. as well as an increase in the Firmicutes family. Although they have very strange names (like almost everything in microbiology), these microorganisms are health factories, since when they digest the compounds, short-chain fatty acids such as butyrate are produced. And these metabolites travel from the intestine to the brain, reducing neuronal inflammation and modulating the production of neurotransmitters key to well-being. There are many tests. In addition to this study, there are other different ones, such as one published in 2024 that linked coffee consumption to an increase in bacteria Lawsonibacter asaccharolyticusa powerful butyrate producer strongly linked to intestinal and mental health. but another published in 2022 showed that both caffeinated and decaffeinated coffee mitigated depressive behaviors and reduced pro-inflammatory cytokines, normalizing the microbiota deregulated by lack of rest. More than a stimulant. For decades, coffee’s relationship with gastrointestinal health has been a topic of debate that is often blamed on reflux. However, current evidence paints a very different picture in moderate doses, since here it is an active tool to maintain a diverse intestinal ecosystem and is also positive to protect us against other diseases. Images | prostooleh on Freepik In Xataka | If the question is “how much caffeine is in each cup of coffee or tea,” this graph offers insightful answers.

The massive flight of investors and millionaires suggests that he has achieved it

For years, Dubai has been the promised land for millionaires from all over the planet who saw the United Arab Emirates as a idyllic place to live without paying taxes. The Iranian attacks with missiles and drones on different infrastructures in Dubai in recent weeks have changed that perception and the financial elite, especially Asian millionaires, are putting their feet (and fortunes) on the run. The city that seduced more than 81,000 millionaires Since 2014, it is now facing an unprecedented flight of capital and talent. The prestige that took decades to build is being tested in a matter of days. ​Explosions in the heart of the city. The last few weeks have left us images that few would have imagined in February. The Fairmont The Palm hotel, located in one of the artificial islands off the coast of Dubai, was hit for an explosion. Days later the remains of an Iranian drone demolished set fire to the iconic Burj Al Arab, the international airport has suffered damage from drone attacks and the american consulate has been the target of another drone attack. The city that boasted of being the safest in the world, in a matter of weeks, has become a scene of war. “The US-Israel war against Iran is undermining that crucial sense of security in Dubai. Dubai’s economic model relies on expatriate residents providing talent, muscle and investment capital. Stability and security are needed to attract skilled foreigners.”, assured to CNBC Jim Krane, researcher at the Baker Institute at Rice University. ​Asian money in retreat. However, the most visible impact is being felt among Asian investors, who had become one of the pillars of Dubai’s financial growth. According to data by Henley & Partners, Dubai is currently home to 237 centimillionaires (people with wealth of $100 million or more) and at least 20 billionaires Asia accounted for 47% of all multinational companies attracted to Dubai International Chamber in 2025, and around a quarter of the more than 2,270 foundations created in the Emirates have Asian ownership, according to data from the consulting firm BSA Law. Bloomberg published that the United Arab Emirates had attracted some 700 billion dollars from millionaires around the world, especially Asians. Singapore and Hong Kong, new chosen destinations. Grace Tang, CEO of Phillip Private Equity, pointed out to Reuters that between 10 and 20 of their customers, mostly Asian, are asking about how transfer your assets to Singapore to protect the value of its assets. Hong Kong also emerges as an alternative. For his part, Felix Lai, from the consulting firm JMS Group, counted to Bloomberg who had organized a private jet flight to transport 15 clients from Oman to Hong Kong at a cost of approximately $300,000. “They didn’t even care about the price,” Lai explained. “They just wanted to leave.” An advisor in Singapore who declined to be identified added that more than half of his 13 clients in the Emirates are seriously considering moving their assets: “Flying back and forth will be complicated even if the conflict ends tomorrow. It’s about trust.” Dubai’s economic model faces its biggest test. Dubai does not depend as directly on the oil industry as its neighbors, but its economy is based on its ability to attract expatriates, your investments and his talent. At the beginning of the year, the Dubai International Finance Center housed 1,289 entities linked to family offices (61% more than the previous year), and the 120 main families in the center jointly managed more than 1.2 billion dollars, according to CNBC. Although stock markets around the world have felt the earthquake resulting from the attacks in an area of ​​strategic resources for trade and energy, the impact of the conflict with Iran has been much more severe and direct for the Gulf markets. The Dubai Stock Exchange (DFM) has fallen more than 16.6% since the start of the war between the US and Israel against Iran. Fitch Ratings had already predicted before the war a real estate correction of up to 15% in 2025 and 2026. Everything indicates that they have fallen short the worst estimates of the financial consequences. Passing panic or structural change? Not all actors in the sector believe that this will lead to a permanent mass flight. Dhruba Jyoti Sengupta, CEO of Wrise Private Middle East in Dubai, pointed out to Reuters that his firm had not observed “serious conversations about capital flight” as its clients remain confident in the country’s long-term resilience. ​Nirbhay Handa, CEO of migration agency for millionaires Multipolitanpointed in Bloomberg “If uncertainty lasts a few weeks, some companies may pause their expansion, but stability will likely return quickly to Dubai as the situation improves.” What does seem clear is that the city will have to rebuild something much more difficult to build than its skyscrapers for millionaires: trust of those who chose it as a home for their money. In Xataka | A company wants to build a €4 billion megacasino in Dubai. The problem is that Dubai prohibits gambling Image | Unsplash (Wael Hneini)

We thought that the great challenge of veganism was vitamin B12. A study suggests that social relationships are

Whatever there is taken the step to veganismfor whatever reasons, knows that the most difficult thing is not to give up cheese or meat, but to face Christmas dinner with the family or the Sunday barbecue with friends, since food is an event with a great social component. In this way, when someone decides to radically change consumption habits in a predominantly omnivorous worldnot only changes the plate, but also social relations. Now science has determined the tactics these people develop in order to survive social frictions. The data. The study, published in September 2025is not limited to conducting a survey among vegan people to analyze the impact on their social relationships. What they did was exhaustive field work between 2017 and 2022, combining in-depth interviews, observation and netnography, which is the analysis of the behavior of online communities. where debates arise about it. The goal here was none other than to understand exactly where and how everyday interactions are “broken.” And above all how they tried to compensate in an almost innate way. Social fractures. The researchers here identified that tensions in a social relationship do not arise from a simple difference of opinion about the most ethical diet, but from what they have called “relational fractures”, which are divided into three very clear areas: Co-execution: The simple act of cooking with another person, such as a partner, or sharing a meal becomes logistically complex. What was once a fluid ritual now requires planning, separate pans, and constant negotiation to arrive at a common dish. Co-learning: Family traditions, like inheriting grandma’s secret meatball recipe, are short-circuited. This means that the exchange of culinary knowledge between omnivores and vegans often comes to a standstill. Activities that may be everyday activities, such as going shopping or choosing a restaurant with other people, become logistical minefields where one has to balance one’s ethical needs with the preferences of others to choose, for example, a restaurant with a menu that suits everyone. Survival kit. So, if relationships fracture, how do vegans avoid becoming isolated? The researchers here discovered that, to maintain social peace and navigate these turbulent waters, vegans develop four specific “relational competencies” that sometimes appear without them realizing it, which we see below. Decoding. This is the ability to “analyze,” meaning vegans learn to anticipate how others will react to their diet and evaluate whether the environment is safe, hostile, or simply curious. Depending on the impression you have, your behavior will adapt to the environment by being more or less open with the topic. Disengagement. The second pillar is to deliberately separate food from social interaction, as it means that one will eat their vegan plate while another eats animal products, prioritizing company and conversation over dietary friction. Chameleon effect. The third adaptation consists of integrating so as not to attract attention in the group. This may mean, for example, bringing food from home to a social gathering or ordering a basic salad at a steakhouse without comment, all to prevent veganism from becoming the central topic of conversation of the evening. Abandonment. The last adaptation that has been detected in some vegans is where they directly give up different shared plans, such as stopping going to certain restaurants or social events. Even, in extreme cases, a distancing has been detected in an interpersonal relationship, since it becomes toxic due to the tensions that are generated. It is not born from nothing. One of the researchers has been exploring “morality in markets” for years and this led her to talk about indigenous and animal consumption practices. In this way, veganism is something that has been scrutinized for a long time in different studiessince it is not just about choosing what to eat, but it is an ethical stance that the omnivorous environment often perceives as a challenge to its own social and cultural customs. The big conclusion that can be drawn from all this is that the transition to a plant-based diet does not only require learning to read nutritional labels or discovering new recipes, but also requires a profound social and emotional re-education.. The long-term success of a vegan lifestyle depends as much on resilience at the supermarket as it does diplomacy at the dining table. Images | Anna Pelzer Xataka | Protein powder has become the star accessory of modern wellness. Nutritionists have something to say

A woman from 7,000 years ago suggests that gender was not an immovable barrier

For decades, our vision of European prehistory has been dominated by a fairly rigid idea regarding the division of labor in communities: men were assigned certain tasks and women others. However, bones have a fascinating habit of disproving our prejudices, as has now happened after analyzing some human remains found in Hungary. What has been seen. This new analysis of human remains Dating back to more than 7,000 years ago, it has revealed an older woman buried not only with typically “masculine” grave goods, but also with marks on her bones that show that she did the same physical work as them. Something that has marked a before and after in gender roles in prehistory. The rule and the exception. To understand the magnitude of the find, an international research team thoroughly analyzed 125 adult skeletons which came from different cemeteries in Hungary. Here the researchers already knew that there were structured gender norms, since the funerary “law” was very clear, indicating that men were buried lying on their right side and accompanied by polished stone tools. In contrast, women stood on their left side and their trousseau was usually composed of belts made of shells. Up until this point, everything seemed to fit into a perfect binary system, until researchers came across the skeleton of an elderly woman. And, unlike the rest, she had been buried with polished stone tools, the classic “masculine” status symbol of her culture. They went further. If the grave goods on this corpse were already an anomaly by the standards of the time, the biomechanical analysis of the skeleton ended up surprising the scientists. In this case, the researchers did not limit themselves to looking at what objects accompanied the dead, but they crossed these data with the patterns of physical activity imprinted on the bones, such as the natural wear and tear of the different parts of the bones. Basically, the bones adapt and deform according to the postures and loads that we endure throughout our lives and that is why they can give us a lot of long-term information about our jobs. Here the researchers discovered that the men of this community tended to have marks associated with prolonged kneeling and intensive use of their arms, probably due to the use of specific tools or carrying work. Something that women did not have because they did not carry out those tasks. The surprise. Here the study skeleton that attracted so much attention revealed the same bone marks and joint wear resulting from kneeling as the men had. In this way, not only was this woman buried as a man, but she lived, worked, and moved like one of them. Neolithic genre. This study brings to the table a fascinating conclusion: Neolithic societies did have marked gender roles and a structured division of labor, but it was not something set in stone that ‘condemned’ a person to a job for being a man or a woman. As science now points out, the roles were “generalized but flexible.” This means that the fact that this community has decided to bury a woman with the honors of a man, recognizing the role she played in life, shows that in Europe seven thousand years ago there was room for exception. Images | engin akyurt In Xataka | 2,000 years ago Epicurus had already understood the secret of pleasure: “Nothing is enough for those who have enough is little.”

Science suggests that it is a great shield against cognitive deterioration

In our society, the fact that grandparents end up taking care of their grandchildren throughout the day or having to pick them up from school It is something quite normalboosted mainly by the problems of conciliation familiar. This is something that has been the subject of much controversy because, when you reach a certain age, carrying the burden of having a child under your responsibility can take its toll. But now science indicates that it has important benefits. New tests. A study published this year in the magazine Psychology and Aging points out that being involved in caring for grandchildren provides a benefit to cognitive health, although it has different important nuances related to sex and time dedicated. The science behind. This study focused on data from English Longitudinal Study of Aging where More than 1,700 grandparents over 50 years of age have been analyzed. In this case, to ensure maximum precision in the results, the researchers used a matching method, comparing grandparent caregivers with those who did not care for their grandchildren, but who did share demographic and health characteristics. What did they see? With this sample on the table, what was seen is that both grandmothers and grandfathers who are caregivers showed higher levels of verbal fluency compared to the control group. Furthermore, both genders had better episodic memory compared to matched controls. In this way, it can be concluded that grandparents who take care of their grandchildren tend to show better cognitive functioning than those who do not. Quality versus quantity. One of the most revealing conclusions of the study debunks a common myth: the amount of time spent is not the determining factor. In this way, spending more or fewer hours caring for one’s grandson or granddaughter does not predict the effect it may have on brain cognition. But what really affects brain health in this case is the diversity of tasks. What was seen is that grandparents who participated in a greater variety of activities experienced better cognitive outcomes. These activities include, for example, preparing food for your grandchildren, spending time playing with them, helping them with their homework, or picking them up from daycare or school. Gender difference. Although both grandfather and grandmother showed higher initial cognitive levels when caring for their grandchildren, with the passage of time it changed. In the case of both sexes, it was observed that both verbal fluency and episodic memory improved substantially over time. But the difference is precisely in the temporal decline, causing grandmothers who have cared for their grandchildren to have a slower cognitive loss over time than caring grandparents, who maintain the same speed of loss. Because? The researchers here suggest that these differences may be due to how they relate to different genders and how they collaborate on care tasks. In this case, grandmothers tend to become much more deeply involved in the physical and emotional care of children. If we turn to the grandparents, we find that they are involved in leisure activities and often carry out care tasks in the company of the grandmothers. This way, you are not as focused on care. The limit. Logically, Maintaining multiple productive roles, such as family caregiving, can promote a more active lifestyle that positively impacts people’s cognitive functions. However, research warns that adding care responsibilities to the usual activities of these grandparents can be stressful and leave our grandparents feeling overwhelmed and with little autonomy. Images | Vitaly Gariev In Xataka | Your grandmother is an evolutionary advantage: science already knows why they generate an indestructible bond with their grandchildren

Genetics suggests that Neanderthal males preferred human females

We have known for years that today’s non-African populations They preserve between 1 and 4% Neanderthal DNA as a legacy of the prehistoric crossings that existed. However, when looking at our X chromosome (which determines sex), geneticists repeatedly encountered an absolute void, a phenomenon that has been dubbed ‘neanderthal desert‘since there was no ancient DNA. And the question here is quite obvious: Why did the imprint of this species disappear from our sex chromosome, but not from the rest of the chromosomes? The key data. From here science began to investigate, and a new published article in Science proposes an answer much more focused on demographics: sex between both species It had a very strong gender bias. That is to say, the fact that a member of each species had sexual relations with great frequency has survived to this day with this genetic imprint. How do you know? What was done to be able to see what happened to the genetic material and its passage between generations within the Neanderthal populations was simply to analyze genomes. Specifically, the DNA of women from current African populations, who do not have any Neanderthal genetics, and compared them with genomes of female Neanderthals, mainly the Neanderthal of Altaibut also specimens of Chagyrskaya and Vindija. The result. Here the researchers realized that the X chromosome of the Neanderthals analyzed presented a large amount of DNA that came from the Homo sapiens. Specifically, an excess of 62% was seen compared to the rest of the organism’s chromosomes. The only thing that confirms is that the genetic exchange between both species was not a one-way change, but rather that both parties were enriched, causing the Neanderthals to also have sapiens DNA, but in different proportions. A matter of preferences. How is such a brutal asymmetry in the sex chromosomes explained? Until now, the most accurate hypothesis to justify our “Neanderthal desert” was biological incompatibility between species. Here it was thought that male hybrids suffered fertility or viability problems if they received this DNA, which caused a negative selection of testicular genes that erased the Neanderthal imprint of our X chromosomes. However, science has now ruled out that this 62% excess on the Neanderthal side is due to the sapiens DNA giving them an evolutionary advantage, since they ended up disappearing in a until now inexplicable way. The conclusion. Everything indicates here that there was an extreme sexual bias in the miscegenation. That is, the crossings occurred overwhelmingly between Neanderthal males and females. Homo sapiens, and always with this pattern. This mating preference persisted across generations, where Neanderthal males preferred females sapiensand the resulting hybrid offspring were also “preferred” in group dynamics. In this way we are faced with the piece that fits into the bidirectional puzzle of our evolutionary history. There are nuances. As usual, there is always a ‘but’ in these stories. In this case, the researchers point out that, although the genetics are quite clear, the behavioral interpretation has nuances, since the pattern we see today could be the result of a mixture of factors. One of them is that societies where women sapiens They left their tribe to join the clans of their Neanderthal partners, introducing their X chromosome into the genetic pool of the other species. Images | Jan Jakubowski In Xataka | The extinction of Neanderthals has always been a mystery. Science now believes that they are still with us

Science now suggests that caffeine could be a “shield” against dementia

For years, the debate about whether coffee is a hero or a villain for health has swung like a pendulum between one position and another. However, science has now given a good reason for the most coffee lovers to drink even more coffee. The reason is in a new study published in JAMA which has put evidence on the table that is difficult to ignore: moderate caffeine consumption not only keeps us alert today, but could be protecting our brain for tomorrow. The data. We talk about how this is evidence that is difficult to ignore precisely because it is not a one-time survey from a weekend, but rather a Harvard research team. analyzed more than 130,000 people for four decades. Specifically, the sample that has been handled in this case has been 131,821 participants, which included health personnel, and a follow-up of up to 43 years was carried out during the years 1980 and 2023. At the end of the study, 11,033 cases of incident dementia were documented, which is what had to begin to be studied. With your diet. Once all this information is available, researchers have had to begin to cross-reference the dietary intakewhich have been updated every four years, with medical histories. Here the primary objective was to look for a pattern that related something in the lives of patients with dementia to their illness. And the truth is that they saw a fairly clear pattern: those who consumed caffeinated coffee had a lower risk of developing dementia compared to those who barely ate it. Something that other studies in the past also pointed out. Neither little nor too much. Logically, the study does not suggest that we should start drinking coffee as if it were water, since the effects of caffeine in large quantities are very harmful to health. Science suggests in this case that the greatest benefit was observed in those who consumed approximately 2 to 3 cups of coffee a day. In concrete figures, it was seen that this consumption reduced the risk of having dementia by 18% and also showed in patients a lower prevalence of subjective cognitive impairment and better scores on objective memory tests. Drink more coffee. According to this specific study, the benefit stabilizes, meaning that it does not improve further, but it does not worsen drastically in this group of patients. But other meta-analyses suggest that with consumption of more than 4 or 5 cups, the benefits can be reversed and generate other problems. Caffeine is key. One of the most interesting findings is the chemical distinction that is made, since researchers separate people who drink caffeinated coffee and those who drink decaffeinated coffee. Here the results were quite clear: decaffeinated coffee consumption is not associated with a decreased risk of dementia or better cognitive performance. This suggests that the neuroprotective effect does not come only from the antioxidants or polyphenols of the bean (which are also in decaffeinated), but caffeine is the active agent main in this equation. The effect of tea. There is a large group of people who do not depend on caffeine to stay awake, but on the caffeine in tea. In this case, tea consumption showed coffee-like associationssince drinking 1 to 2 cups a day was also linked to a reduced risk of dementia and better cognitive function. This is something that reinforces the theory that caffeine and other compounds such as L-theanine play a protective role in our nervous system. Why does it work? Although in this case the study is not focused on telling us the reasons, the authors propose a series of biological mechanisms to understand it. The first of them is that caffeine blocks adenosine receptors in the brainwhich not only makes us more awake, but could reduce the accumulation of beta-amyloid, the protein associated with Alzheimer’s when it is in large quantities. In addition to this, caffeine is also believed to reduce pro-inflammatory cytokines in the brain, mitigating neuroinflammation that precedes cognitive decline. And if we lacked reasons to defend caffeine, it is added that it improves insulin sensitivity and vascular function, two factors that, when they fail, open the door to dementia. The small print. Although variables such as tobacco, exercise and diet were adjusted for, it cannot be definitively proven that coffee causes brain protection. It may always be the case that people with early cognitive decline give up coffee because it makes them sick, but the researchers tried to control for this by excluding the first few years of follow-up. Furthermore, it must be taken into account that the participants were mostly health professionals with higher education, so the results could vary in populations with other lifestyles or genetics. Enjoy, but don’t force yourself. The person who already enjoys 2-3 cups of coffee a day has one more scientific reason to do so without guilt in this case, since it is in the “sweet spot” of neurological protection. But if there are people who do not like coffee or it makes them very nervous, there is no need to force it, since the quality of sleep and the exercise They remain the undisputed kings of brain health. Images | Fahmi Fakhrudin In Xataka | We believed that the early onset of dementia was due to genetic causes. we were wrong

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