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We believed that the brain evolved to be rational. Science has a much more uncomfortable answer

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We love to think of ourselves as deeply logical beings, since after all, we call ourselves Homo sapienswhich can be translated as the ‘man who thinks’. When we make a decision, from what car to buy to who to vote for, we like to believe we’ve weighed the pros and cons with the coolness of an algorithm. But biological reality acts as a bucket of cold water by pointing out that our mind has evolved to survivenot to think rationally. The myth of the logic machine. To understand why we sometimes make decisions that seem absurd or get carried away by cognitive biases, we must look to our evolutionary past. The classics of modern evolutionary psychology, driven by figures such as Leda Cosmides and John Tooby, established a fundamental basis when seeing that our current cognitive mechanisms were forged in ancestral environments. Here we must bear in mind that in the savanna, stopping to statistically calculate the probability that a rustling in the undergrowth was a lion or simply the wind was a recipe that could end with almost certain death. The one who survived was the one who ran away without thinking rationally. It is not exclusive. This decision-making architecture is not unique to us, since science has already traced the evolutionary roots of our decisions. comparing us with non-human primates. The result is that monkeys also display economic biases and irrationalities similar to ours, demonstrating that many of our logical “errors” are hardwired into our evolutionary lineage. Minimal effort. If we are not rational in the strict sense, what are we? This is where one of the most interesting concepts in recent cognitive science comes in, pointing to an idea that changes the way we see ourselves: “resource rationality.” According to this modelthe human mind is not irrational, but hyperefficient, since the brain consumes an enormous amount of energy and time is always limited. With this premise, what our mind does is optimize our decisions taking into account the limited resources available to it. This causes us to take mental shortcuts and make biases because processing all the information perfectly would be a slow and exhausting process. In other words, the brain prefers a quick, “good enough” decision that keeps us alive, over a logically perfect decision that leaves us paralyzed analyzing data. Think to justify ourselves. In a 2021 article published in American Psychologistit is argued that humans are not nearly as “rational” as we tend to believe, and they suggest that rationalization itself may be a human adaptation. Often, we do not use our intellect to arrive at objective truth, but rather to justify decisions we have already made emotionally or intuitively. In a complex social environment, having the ability to convince others, justify our behavior, and coordinate group action was much more useful for social survival than being a solitary, purely objective thinker. We are adapting. All of this does not mean that we have a “broken” mind, but rather that science suggests that our mental processes should be judged not by whether they comply with textbook laws of probability, but by how well they function in the real, physical environment in which we operate. In short, it is not that we are incapable of reasons but that human rationality is limited, contextual and tremendously practical. We were not designed by evolution to pass formal logic exams or to be perfect algorithms with no margin for error. We were designed to make decisions that, with the incomplete information and limited time we have, allow us to see a new dawn. Images | Wes Hicks In Xataka | We had always believed that evolution had been arrested for thousands of years. The redheads were telling us the opposite

Faced with the dilemma of whether long or short vacations are better to disconnect, science has a very clear answer.

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Spain is not only divided into ‘with and sincebollists‘. If we talk about vacations, there is another dilemma that confronts people and even causes tensions between co-workers: Is it better to enjoy a long break, an impasse of several weeks that allows us to forget about the stress of the office and (hopefully) take a trip to some distant destination, or is it preferable to dose the 30 calendar days of rest that corresponds to us by law to take small getaways? If you ask your colleagues, you will probably find supporters of one or the other, but things change when you consult the experts. They are clear about it. “Long vacation or short vacation?” The question is not ours. It was launched a few days ago by doctor Antelm Pujol in a tweet which already has hundreds of thousands of views and has been shared more than 600 times, which demonstrates, among other things, that the topic generates interest. And it’s quite understandable. As a general rule, those of us who work in Spain have at least 30 calendar days (or 22 working days) of vacation, a limited time that we must manage correctly if we want to get the most out of it. So, what is best to disconnect? Should we take three weeks at a time to go to Cancun or Thailand or should we take several five-day getaways? Click on the image to go to the tweet. A matter of taste, right? More or less. Factors such as family balance, the budget managed by each person or personal tastes come into play in the decision: there are people who love to get away from their office for weeks and others who feel the house collapse after four days of vacation. However, if what we are looking for are scientific answers, things change. A quick Google search arrives to find research and experts who agree on which of the two options is more ‘intelligent’ or, at least, offers a better strategy to obtain the greatest possible rest. What option is that? Do not enjoy all the days of rest at once, but segment them over several months. “Taking more frequent vacations could be a better strategy to maintain well-being,” Pujol shares in his tweet. He doesn’t talk just to talk. In the same post he quotes an academic study published in 2012 in Journal of Happiness Studies in which three psychologists from the Radboud University (Netherlands) examine what impact vacations have on employees’ health and well-being. It is interesting because they focus on aspects such as the duration of trips, the quality of sleep or the organization of activities. And what did they discover? After interviewing a group of workers who went on a trip for an average of 23 days, the experts analyzed how their sense of well-being evolved. And one of the aspects they paid the most attention to was the length of the vacation. Were people happier the more time they spent offline? Did the feeling of relaxation and happiness ‘hit the ceiling’ at any point? Is a long vacation always a better vacation? The answer is no. The health and well-being of study participants increased during the first eight days of vacation, a trend that became especially pronounced between the fourth and eighth days of vacation. From there the evolution was not so clear or positive. “In summary, health and well-being levels improved rapidly over the holiday and peaked on the eighth day,” synthesize psychologists from Radboud University. Did you find out anything else? Yes. They also discovered that throughout the first week of returning to work “levels of health and well-being decreased and resembled baseline levels prior to vacation.” In short, the relaxing effect of the vacation fades after seven days. It may sound demoralizing, but it is an important nuance if what we are looking for is a strategy to get the most out of our 30 days of vacation. If relaxation reaches its peak on the eighth day and its effect on our mental health is lost shortly after returning to the office, isn’t it better to divide them into short breaks? What do the experts say? “Short, frequent vacations have a more positive impact than long, infrequent vacations. The bottom line is that you don’t need a whole month to see significant benefits because longer vacations don’t improve well-being more and they don’t make the benefits last longer,” explains to Men’s Health Marcos Vázquez, disseminator. “Taking seven to ten days off more frequently seems to increase well-being the most.” Does it only matter how much? Not at all. The how also matters (and a lot). It’s not just about whether the vacation lasts more or fewer days. If what we want is to disconnect, relax and increase our sense of mental well-being, we must take other important issues into account. For example, hours of sleep. The Dutch psychologists found that, on average, the subjects in their study slept 7.4 hours at night while on vacation, almost an hour more than what they normally did when they worked (6.7 hours). It is a fundamental detail because the experts confirmed an evident relationship between the duration and quality of sleep and the levels of well-being and health recorded by tourists. Is it the only study on the subject? No. The effects of vacation length they have analyzed them other experts such as Rui Cui, from the Shichuan Universityin China. In 2023 he published other paper in Tourism Review in which he notes an effect similar to that seen by his Dutch colleagues. “The regenerative effects were systematically greater in the group that traveled than in the group that did not. Furthermore, an inverted ‘U’-shaped relationship was observed between the duration of the trip and the regenerative effect of the vacation,” comment the Chinese expert. “A moderate duration had more intense regenerative effects than a duration that was too long or too short.” And before the holidays? In reality, it is … Read more

Europe wants to put an end to the particular Iberian exception of the Spanish train. And Spain has a clear answer: no.

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There are investments and investments. More or less necessary. More or less large. But there are also more or less viable ones. And, of course, the Ministry of Transport considers that the European Commission’s proposal to change all roads from Iberian gauge to international gauge is anything but viable. And they have a good reason: 30,000 million euros. What does Europe want? In October 2025, The European Commission presented its project to cement, once and for all, the connection between Madrid and Lisbon with high-speed trains. After many delays, if the plans are fulfilled and both cities end up being united in 2030 with a single train, high speed will arrive on this line 20 years late. In the writing The bases that the routes must follow are reflected and there is an important paragraph in them: With the ambition to fully integrate the Lisbon–Madrid high-speed rail connection into the broader high-speed network in Spain and France, adopting the European standard nominal gauge of 1,435 mm is a key step. In this way, the competitiveness of long-distance passenger traffic will be strengthened. By connecting Portugal and Spain, and extending to France, the Lisbon–Madrid high-speed rail connection has a clear cross-border and Union dimension In it it is clear that we are talking about the Madrid-Lisbon line but on the occasion of this text, public entities must study the economic viability of migrating the railway network to the international gauge and definitively abandoning the Iberian gauge. The answer. No. Simple and concise. According to The Countrya medium that claims to have had access to internal documents of the Ministry of Transportation, the Government’s response to this migration is a resounding “no.” The reasons are as simple as that it would take 30 years of works and an investment of 30,000 million euros to reverse the Iberian exceptionalism of the Spanish and Portuguese train. In the documents that Spain will present to Brussels, it is specified that the matter is not viable in its entirety or in part since the possibility of installing “third threads or lanes to achieve mixed widths” was contemplated, they explain in the medium. No, no and no. They explain in The Country that the Ministry of Transportation rejects all the options that have been put on the table: Changing exclusively the lines of the European corridors: it would leave, according to Transport, more than 5,000 km of the network isolated. Implement a mixed width with third rails or threads: discarded due to the complexity of the work and the high maintenance cost Change all Iberian gauge roads: Transport considers it unapproachable although it has been the most studied option because it is ideal. What is this track width? Spain, since the 19th century it has lived in an Iberian exceptionality next to Portugal. Throughout this century, the railway was gaining followers all over the world. During its expansion, the lines were built with different track widths, taking into account the particularities of the terrain. In Europe, the number of tracks built with a width of 1,435 mm multiplied and ended up becoming established. Everything above it is considered “wide gauge” and below it as “narrow gauge” because those 1,435 mm were accepted as the standard. This is how the international gauge was born. In Spain, however, we chose to build our railway network on a track gauge of 1,672 millimeters, defended by three engineers who were entrusted with the task of projecting the future of the Spanish train. They argued that a wider track width allowed the use of more powerful locomotives and that this was essential in a mountainous country like ours. And the consequences? The consequences were immediate. Already in the middle of the 19th century From Portugal they asked Spain by letter to desist from building their roads with this new gauge because they would be isolated from Europe. And the problem, evidently, was greater for Portugal, which was dragged along by the Spanish decision. Spain, as you imagine, did not give up and now lives between three gauges of road: the international one (for about 4,000 km of high speed), the Iberian one (for 13,000 km of Cercanías) and the metric width (1,210 km for especially mountainous terrain). This is a problem for connectivity between tracks because trains cannot jump from one to another, except for the Talgo Avril. And it’s an advantage. At least for Renfe. And Renfe can take advantage of this particularity in some very specific points on the Peninsula. For example, in Madrid-Galicia, international gauge and Iberian gauge are used, already in the Galician part. Only Renfe has trains that can jump from one track gauge to another, so competition is eliminated. And the same will happen in Portugal. The connection between Madrid and Lisbon is being built on an international gauge but the Portuguese high-speed line between Lisbon and Porto will operate on an Iberian gauge. This leaves Renfe as the only company that could operate a Madrid-Porto train passing through Lisbon without the need to transfer. Now it is better understood why Renfe will invest in converting the Avrils fixed gauge on variable gauge trains and why Transportes believes that Portugal is a great market opportunity. Photo | Falk2 In Xataka | Renfe offers its juiciest contract: 4,000 million euros to buy trains. And everything indicates that he will not stay in Spain

The Medici have been carrying an apparently unsolvable mystery since the 16th century. Science finally has an answer

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The uncle of a famous superhero said that ‘with great power comes great responsibility’. If what we are talking about is the Medici, the saga of bankers, prelates, patrons and rulers who dominated Tuscany between the 15th and 18th centuries, great power entailed something else… enormous risk. One filled with rivalries and plots that could come from both external enemies and the family itself. Hence the chroniclers carry four centuries wondering why some of its main figures died suddenly at the end of the 16th century. Disease? Bad luck? Murder by poisoning? Science already has an answer. Worthy of Agatha Christie. The British queen of suspense left us exciting novels, but few match the Medici family chronicle in mysteries and script twists. It takes reviewing some of the events that shook the Florentine saga in the second half of the 16th century to prove it. In 1562 the cardinal Giovanni de Medici He died at the age of 19 after a trip along the coast accompanied by his mother, Eleonora and his little brother Garzia, who also died around the same time. Only 25 years later the drama hit the family again through his brother, the Grand Duke Francesco I. He died in 1587, aged 46. Just a few hours later his wife did it Bianca. Quite a coincidence, right? That is what they thought the contemporaries of Francesco and Bianca, who in a matter of 24 hours watched the two members of one of the most powerful couples in the region go to their graves. In theory the cause of death was malaria, but… Wasn’t it a coincidence that husband and wife died just a few hours apart? Wasn’t it suspicious that exactly the same thing had happened to them as had happened to Giovanni 25 years earlier? Rumors of murder arose and eyes soon turned to Ferdinandanother Medici. The Tuscans of the time cannot be blamed for their suspicion. Ferdinando was next in the line of succession and risked being overtaken on the right by his nephew, the illegitimate son of Francesco I. As if that were not enough to spark rumors, they say that he had visited the Grand Duke and his wife shortly before the couple fell ill. How long does a suspicion last? Well, more than four centuries, which is how long historians have been turning around Francesco’s story. Why did he die in such a sudden and premature manner? Was it malaria? Arsenic poisoning perhaps? Did Ferdinando plot against them? Science tried to solve the mystery a long time ago, but it has only added fuel to the fire. At the time, the analysis of exhumed bone remains confirmed the malaria theory; but other studies, including one from 2006 carried out by professors and forensic experts from Italy and based on toxicological examinations, pointed to poisoning. An impossible labyrinth. The testimonies of the time do not help either. We know that Francesco and Bianca showed symptoms compatible with malaria and that the Medici family doctors tried to cure them with bloodletting, a method with which they surely (now we understand) only made things worse. The problem is that supporters of the poisoning theory also have their own arguments. Donatella Lippi, one of the authors of the 2006 study, remember that although it is confirmed that the couple contracted malaria, it does not mean that that was the cause of death. It even slips that in the Vatican Library there are testimonies that speak of skin rashes and other symptoms that could well be related to arsenic poisoning. And the genetic analysis arrived. This is how things were until a few weeks ago, when a group of researchers from the University of Pisa and Yale published a new study in iScience in which they collect their conclusions after subjecting bone remains of two members of the Medici family to DNA analysis: Giovanni, who died in 1562, and Francesco, who followed him to the tomb 25 years later. To be more precise, the researchers extracted genetic material from four rib samples, three from the duke and one from the cardinal. His remains and those of other Medici rest in mausoleums located in the Basilica of San LorenzoFlorence. Go one step further. In the past, researchers had already tried to clear up the mystery with paleo-immunological analyzes that, although they yielded some interesting conclusions, did not serve to silence “the rumors.” as you recognize Valentina Ciuffra, professor of History of Medicine at the University of Pisa and one of the authors of the study published in iScience. It was necessary to go one step further. And that is precisely what the Pisa and Yale team intended by using advanced methods to study ancient DNAgenetic material extracted from samples that are centuries and centuries old. What have they found out? That both Giovanni and his brother Francesco suffered from malaria. We know this because researchers located traces of Pasmodiumthe parasitic protozoa that cause the disease. One of the two Medici brothers even suffered it in a particularly bloody way: both the bones of the cardinal and the Grand Duke preserved traces of Pasmodium faciparumthe most lethal species among humans; but in the case of the latter (Francesco) greater molecular traces of P. malarie. What does that mean? That the Grand Duke who died in October 1587 showed traces of two species of malaria. It is not something exceptional. Experts have already detected samples in Belgium that suggest the coexistence of several species of malaria, although they insist that further research is necessary before stating with complete certainty that both species circulated in 16th century Italy. “With scientific certainty”. For the authors of the new DNA study, their work is conclusive and settles a 400-year-old mystery: “This genetic analysis confirms historical accounts, as well as previous research. We can now affirm with scientific certainty that malaria, and not poisoning, was the cause of the death of Grand Duke Francesco de’ Medici,” stands out Valentina Giuffra. In case there … Read more

China has reached the asteroid that has been driving astronomers crazy for a decade. And your first photo is already changing the answer

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After 400 days of travel, the Chinese Tianwen-2 probe has reached your goal: object 469219 Kamo’oalewa (2016HO3). The entire world astronomical community has its sights set on this trip, for the answers it can provide to a mystery that has been going on for more than a decade. However, as usually happens with missions carried out by China, we had little information about the journey until the ship was already at its destination. This occurred on July 4, although the Chinese National Space Administration, CNSA, announced it this July 6. Be that as it may, the important thing is that China has reached Kamo’oalewa, that terrestrial “minimoon” that has given scientists so many headaches since it was discovered in 2016. Now comes the good. Tianwen-2 was released on May 29, 2025. 400 days later, it has reached its first stop, just 20 kilometers from Kamo’oalewa. There, he has taken the first photos, which will help him map this object, in order to determine the best places for sampling. Then, it will be time to get down to work, to collect a series of samples that will be sent to Earth in 2027. Then, we will have a definitive answer to the million-dollar question: Is Kamo’oalewa an asteroid or a fragment that was ejected from the Moon? The instruments. This probe has 11 payloads, including instruments that will allow it to study both Kamo’oalewa and its next target: comet 311P/PANSTARRS. These instruments include cameras, laser measuring devices, spectrometers, sonar radars and particle analyzers. It also includes the DIANA dust analyzer, developed in Italy. First mission: map the surface. Currently, the Chinese probe is taking photographs from different angles to create a 3D model that will allow establishing the best places to take samples. Broadly speaking, these places must meet two requirements: be scientifically interesting and not pose risks for sampling. The latter includes, for example, no unstable ground or loose rocks. Second mission: take samples. Since the mission left without knowing exactly what the surface of Kamo’oalewa will be like, Tianwen-2 travels prepared to take samples through three different methods: suspension, touch and match and anchor and coupling. The first consists of keeping the probe in hover, without landing on the object, and taking out a robotic arm that will skim the surface to obtain the samples. The second method, on the other hand, uses a disc-shaped, gas-powered head that briefly but more strongly touches the surface. Afterwards, rotating brushes are released that, together with bursts of air, sweep away the material released with that blow of the disc. Finally, the anchoring and docking method consists of releasing four robotic arms that are fixed to the surface to extract material for a longer period of time. It would be the first time this method has been used in deep space. Tianwen-2 has been traveling for 400 days Third mission: send them to Earth. The samples will be sent to Earth in 2027 for analysis. However, during Tianwen-2’s flyby of Kamo’oalewa, some inquiries are already being made about it. Asteroid or lunar fragment? Until now, all that was known about Kamo’oalewa were hypotheses or estimates. It was believed to measure between 40 and 100 meters in diameter and that It had to be a fragment released from the Moon after a collision or an asteroid. The first hypothesis arose from a study using spectrometry, in which it was concluded that its surface is rich in silicates, like that of the Moon. The second has several origins, although gained weight after another study in which several collisions were modeled on a simulated Moon. In very few cases the released fragments became quasi-satellites of the Earth, so the asteroid would fit better. In its first days in the vicinity of Kamo’oalewa, Tianwen-2 has made a measurement of the surface reflectance of the object, which suggests that it has a high geometric albedo. That of the Moon is quite low, so the asteroid hypothesis would still fit. On the other hand, the first data indicate that Kamo’oalewa measures 20 meters in diameter. It is less than what was originally estimated, but practically the same as what was calculated with observations made by James Webb. According to a study published on July 1in these it was calculated that it would measure 18 meters and, again, it was suggested that it be an asteroid. Specifically, one of type E. What is this about quasi-satellites? Kamo’oalewa is considered a quasi-satellite of the Earth because, when viewed from our planet, it appears to revolve around us. But it’s not true. In reality, this object revolves around the Sun, like the Earth. What happens is that it has a period similar to that on Earth. It also takes about a year to completely circle the sun. This, together with the geometry of its orbit, creates that optical effect that it is actually a kind of terrestrial mini-moon. Now we know that, possibly, in addition to not being a mini moon Due to its orbit, it is not made of fragments of our satellite either. At least, it seems most likely, although, of course, we will have to wait for the samples to reach Earth. Then we can definitively put the mystery to rest. Image | CNSA In Xataka | The Earth has moons that we don’t know about: exploring them is key to revealing the secrets of our solar system

If the question is how to avoid heat stroke in summer, in Japan they have an increasingly popular answer: thermal bracelets

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It happened ago just over a year. Montserrat Aguilar had completed her day as a cleaning service worker in Barcelona when, already at home, collapsed and died. He had spent hours sweeping the streets of Raval in the sun on a day when temperatures in Barcelona exceeded 35ºC. Although at the beginning of 2026 the family I was still waiting based on the results of the final autopsy, his death unleashed a intense (and bitter) debate about the conditions faced by workers who, like her, walk the streets during heat waves. This year in Barcelona they wanted to cure their health with technology well known in Japan: bracelets capable of anticipating heat strokes. What has happened? that in full extreme heat wavewith the thermometer exceeding 40ºC In Barcelona, ​​the Barcelona City Council has decided to reinforce the security of the operators who provide public services on the street using technology. A few weeks ago he distributed 1,400 bracelets thermal among the staff responsible for keeping the city clean, providing public lighting and taking care of the garden areas. Is it the only measure? No. The Newspaper precise other measures with which Barcelona wants to prevent extreme temperatures from taking their toll on those who work on the street. For example, adapting the workday of gardeners in summer, advancing the start and end times to avoid the most dangerous periods, or adopting special protocols, designed for the dog days. Is it enough? No. Sensors and protocols are welcome, but unions insist they are not enough. “Non-exposure is the best prevention,” claims Carlos del Barrio, from CCOO, in The Newspaper. Workers’ representatives recall that “no measure is sufficient on its own” and demand greater investment to, among other things, add air conditioning to cars. Without going any further, the Commissions remember that a relevant part of the fleet is still not acclimatized and there are even vehicles (such as irrigation vehicles) that have the engine located right under the seat, something not very desirable in August. How do the bracelets work? They basically fit the operator’s wrist and control their temperature. When they detect that it rises too high and approaches dangerous levels, it emits a signal (vibrates and lights up) so you can take action. In Barcelona has it happened before. When this happens and the thermal bracelet issues its warning, the operator must stop, find a shady place, drink water and inform his supervisor. The bracelet itself will inform you with a light signal (green, in this case) when you are ready to continue. In the specific case of Barcelona, ​​Parks and Gardens has invested almost 60,000 euros in sensors from the company Metalco, devices designed to warn the user “two levels before” of heat stroke. “It is set to activate the alarm when the deep temperature reaches approximately 38ºC.” That is the general guideline. In practice, the sensor must take into account the conditions of each user. The Department of the Interior has also opted for a similar solution, with devices for the Mossos and firefighters. Is it something new? Thermal bracelets have been used for a long time. And they are certainly not exclusive to Catalonia or Spain. As I remembered a few days ago The Confidential There is a Japanese company that has been dedicated to them for a few years now: Biodata Bankcreated in 2018 and with headquarters in Tokyo. Its catalog includes Canaria+, a bracelet designed to detect “subtle changes in thermal stress” and that helps the wearer control their rest, hydration and food. When the sensor detects that the body is having difficulty dissipating heat, it issues a warning with light, sound and vibration. The moment it thinks the risk has disappeared, it reports again with a green light. “We felt it was necessary to have a system in place and take action before a person collapsed,” explains the company’s CEO, Takeshi Anzai. Regarding his bracelet, he clarifies that “the algorithm adapts” to whoever uses it, although it starts from four levels. The first is free of danger, with the temperature below 37ºC. The second rises to a maximum of 38.3ºC and reveals a “latent risk.” With the third (37.7-39ºC, depending on the person) the alerts go off. The last, the most critical, ranges from 38.7 to 40ºC. Is it only used in Spain? At all. In fact Japan is another good example. Last year the World Economic Forum actually dedicated an extensive report to the “lessons” that the country offers to overcome extreme heat waves and among its resources included wrist sensors designed to detect sudden increases in body temperature and, thus, prevent heat stroke. One of the organizations that has opted for them there is the Tokyo Metropolitan Government, which has distributed thermal bracelets among elderly people with reduced mobility, teachers and students who go to public schools and certain workers who have to work outdoors. “In Japan last year the number of people urgently transported due to heat stroke exceeded 100,000. In cities like Tokyo, the demand for ambulances became so high that authorities issued alerts asking the population to make appropriate use of emergencies,” remember Anzai. Images | Barcelona City Council 1 and 2 and Biodata Bank In Xataka | The French are so desperate about the heat wave that they have started painting the outside of their houses with chalk

To the question of which Spaniard has the highest quality semen, the answer is clear: it is not the people of Madrid.

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Semen also has geography. And in Spain, Madrid does not fare well. Let’s assume that semen quality has been declining for decades. In Spain it has fallen 28% in just 15 years, a 78% if we value the last two decades. That is to say, a concentration of sperm is produced so low that it is less than half of what it was in the 70s. And it continues in constant regression. With this breeding ground, the question is: and which region is coping best with this decline? Alcohol and coffee have nothing to do with each other. The investigation analyzed 386 men seen in seven Spanish fertility clinics—such as the Bernabeu Institute—between 2024 and 2025. After adjusting variables such as body mass index, exercise, and alcohol, tobacco, or coffee consumption, the authors observed that men from the north recorded the best seminal parameters, even when their habits were similar to those of other regions. This gives us a clue to talk about pollution, environmental inequality and public health. The results have been presented at the 42nd congress of the European Society of Human Reproduction and Embryology (ESHRE). AND In it we can find clear differences in semen quality depending on the area in which the donors live. Those who win this game are the residents of the north, with Asturias and Cantabria far ahead of Madrid and the center of the peninsula. But there is fine print. More agile, faster. The total count of motile sperm is striking, almost double in the north than in the central area. In data: 94.35 million on average compared to 50.11 million in the central area. This index talk about health: “the northern region also presented the highest average sperm concentration (80.96 million/ml) and sperm motility (44.79%), compared to 55.4% in southern Spain and 53.4% ​​in the center.” If diet, exercise or substance use alone do not draw this map of semen quality, what does? The first conjectures point to a population that breathes worse, drinks and involuntarily incorporates into its body part of the atmospheric pollution, a mixture of industrial and agricultural toxins, where endocrine disruptors in plasticspesticides and everyday cosmetics. Out of the pot. Beyond Spain, the pattern repeats itself: studies with fertile men In cities such as Copenhagen, Paris, Edinburgh and Turku, they already showed in the early 2000s that the Finns had the highest sperm concentrations while the Danes recorded the lowest values, with also variations in mobility depending on the city. If we take a look at the retrospective analyzes of French donors found significant differences within the country itself in volume, concentration, and total number of sperm. The north wins again. In general, the men of the nordic west They have worse semen quality than those from the Baltic area, in parallel with a higher incidence of testicular cancer, another marker of male reproductive stress. Does better semen equal more pregnancies? Not necessarily, but almost. Let us keep in mind that, although the relationship with fertility is not linear, below certain thresholds of concentration and mobility, the probability of spontaneous pregnancy decreases considerably. To understand what “better semen” means, it is worth going down a level. According to the World Health Organization, reference values ​​are measured in concentration (millions of sperm per milliliter), ejaculate volume, percentage of motile sperm and proportion of sperm with morphology considered normal. It is necessary to distinguish between progressive sperm (the vanguard that advances efficiently), versus non-progressive and completely immotile ones. In morphology, the shape of the head, middle piece and tail (flagellum) is evaluated, since anatomical alterations can make fertilization difficult. Plastics and fertility. By the way: nitrile and latex gloves release plastic microparticles and contaminate environmental measurements does not invalidate that the presence of endocrine disruptors in human tissue does not affect male fertility. The evidence is solid. For example, a 2023 study that analyzed 6 human testicles and 30 semen samples found microplastics both in tissue and fluid: around 0.23 ± 0.45 particles per milliliter in semen and 11.60 ± 15.52 particles per gram of testicle, with sizes mostly between 20 and 100 microns, finding polystyrene in testicles and polyethylene and PVC in semen. The problem is broader. The taboo of male fertility, treated as a private matter, has obscured problems that can be investigated as a collective indicator. And this deterioration does not respond, or not only, to individual behavior. The greatest weight lies in the place you livenot in the genes you carry. A cardinal clue: of course smoking, drinking or moving more or less matter, but it does not depend so much on personal decisions. A debate that is more political than folkloric (and health and regulatory). A cocktail of bisphenol A, methyl, ethyl, propyl and butylparabens, benzophenones and phthalate metabolites is directly associated with significant reductions in total and progressive sperm motility. Therefore, Asturias beating Madrid is not something to celebrate, but rather to raise the alarm about the qualities of the water – it will not be that good -, what pesticides are used nearby and what mix of chemicals goes through daily life. The tip of an iceberg that does not lie in who comes out better off, but rather in the cost of those who come out worse off. Images | Unsplash (1, 2 and 3) In Xataka | We already know how much we Spaniards masturbate at work (and what is more important: which communities win) In Xataka | If you are worried about the quality of your sperm, science has a clear recipe for you: ejaculate more

We have searched for the formula for the definitive pre-workout breakfast. The answer from science is much simpler

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Everyone who gets up early to go to the gym has wondered on some occasion whether it is better to go to the gym without having any breakfast, just have a coffee to get energy, or prepare a large, very satiating breakfast. In this case, the quick information that we find on the Internet can lead to confusion, since depending on what you look at it will show very different advice, and that is why you have to focus. what the experts point out. The body’s gasoline. If you are going to do a high-intensity workout that is not limited to simply taking a morning walk, logically you have to offer some fuel to the body in the form of carbohydrates. These are the undisputed kings to have quick and efficient energy when, for example, starting to lift a lot of weight on a bench. Here the different guides agree that consuming carbohydrates before exercise helps maintain blood glucose levels and preserves glycogen reserves in the muscles, which are our most immediate fuel. That is, they prevent you from running out of “battery” in the middle of the session and end up giving the dreaded ‘bird’ when training. And this is what the famous ‘pre-workouts’ rely on in the form of quick doses of carbohydrates that are absorbed very quickly. The protein. In addition to fuel, it is also noted that adding a moderate amount of protein in the morning is appropriate. This is based on the need to prevent muscle damage and promote recovery, especially if the routine includes strength training. When to take it. The biggest mistake before training is not always ‘what’ you eat, but ‘when’. Here the evidence establishes an optimal window of 1 to 4 hours before exercise to make a solid intake rich in carbohydrates. However, in the real world, few get up at four in the morning to eat breakfast before hitting the gym at seven in the morning. The strategy. If the time frame is short, the strategy must change drastically, since organizations such as the United States Anti-Doping Agency they point Because there are several digestive enemies in pre-workout: Fiber should be avoided since it slows down gastric emptying and can cause serious intestinal discomfort with great effort. You should avoid fats due to heavy and energetically costly digestion, making foods that are easier to digest ideal before training. Just before starting training, it is not best to take protein, since it will not be digested and will not arrive in time to be useful in training, meaning it should be taken an hour before training or after it. There is no definitive breakfast. If someone offers a series of preparations without distinguishing the audience for which they are intended, the truth is that they are lying. The most important point here is that nutrition should always be individualized for the needs of each person, because breakfast for someone who is going to make a great effort is not the same as breakfast for another person who will limit themselves to taking a brisk walk. The time between breakfast and the start of exercise is also important, since the tighter it is, the more priority must be given to light foods that are absorbed quickly. All this means that it is not easy advice and should not be limited to a generic recipe book. Images | Anastase Maragos In Xataka | Walking does not count as “exercising”: for the 10,000 steps a day to be effective, the x3 rule must be applied

His answer is called Zhuri and it already works

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USA takes years working on methods to obtain solar energy directly from space. What is known as space solar energy is shown as an improvement on the conventional solar plants that we have here on Earth. The density of solar energy in orbit is six times greater than on Earth and the problem of weather interference is eliminated. However, it is true that there are quite a few technological obstacles that must be resolved. Although Europe, the United Kingdom and Japan have already made some proposals, the United States has a very prominent activity around the implementation of this type of projects. Therefore, it was to be expected that sooner or later China, the North American country’s eternal space rival, would join. After presenting several proposals project, Zhuri has finally been selected, with which Xidian University it has already started to work. From geostationary orbit to your electrical devices. The Zhuri mechanism, which means “chasing the Sun” in Chinese, consists of several steps. First, a 4.8-meter dome-shaped mirror suspended on a 75-meter tower is used, which is responsible for concentrating sunlight on a series of panels, similar to those used on Earth. This sunlight is used to obtain electricity, which cannot be transmitted directly in space, so it is then converted into microwaves, which can travel more efficiently. These then pass to a rectifying antenna, known as a rectenna, whose role is to transform these microwaves back into direct current electricity. That is the electricity that reaches the Earth. Other devices. In addition to the mirrors mentioned, Fresnel lenses of 2 to 7 meters wide have also been tested, as they are capable of focusing light even more efficiently, with less expenditure of materials. They even include cooling liquids that help manage solar heat, avoiding some of the inconveniences that it could cause. The first tests have been a success. In the first tests, scientists from Xidian University have obtained energy in the order of kilowatts, so for now the results are very positive. They are not alone. In the United States there are several projects aimed at obtaining solar energy directly from space. For example, Caltech has been researching in this area since 2013 and has already carried out some experiments in orbit in 2023. Also some private companies, as Goalplan to power their data centers with space solar energy by 2030. And, of course, the United States government could not be absent. The ARACHNE project, of the Air Force, is based precisely on this same goal. On the other hand, in Europe the ESA has the project Solaris and UK Space Solar. Both plan to start operating in 2030. And above all, Japan stands out, which has been researching in this area for decades and was one of the first countries to test wireless power transmission. Not to be confused with Reflect Orbital. The United States has other similar projects, as Reflect Orbitalbut they should not be confused, as they are much more controversial. With them, what reaches the Earth is not electrical energy, as with everything we have mentioned so far, but rather sunlight itself, which is “squeezed” even during the night. The objective of both types of projects is similar, but the means are very different. Beware of challenges. All countries that have tried to obtain space solar energy have encountered the same challenges. For example, they highlight problems in addressing the ease of deployment of folding or self-assembling structures, achieving precise microwave aiming, and ensuring the safety of the beams, both for the environment and for aircraft crossing the area where this electrical energy is being obtained. To address some of these handicaps, China uses modular units that fly in formation rather than a single massive structure, thereby improving endurance and making maintenance easier. Short term goals. Logically, the ultimate goal of this type of project is to bring solar energy to any part of the Earth. However, for now, we want to go step by step and achieve small preliminary challenges, such as wireless charging of satellites in orbit or the supply of lunar bases in orbit or on the lunar surface. Image | POT In Xataka | We knew there was water on the Moon, but not why some craters were empty. Finally we have the answer

Ukraine no longer wants to send soldiers to the front. His answer is an “unpublished Frankenstein”: robot-tanks with machine guns

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The British inventor Ernest Swinton first proposed using “land ships” to cross trenches and avoid sending infantry directly into fire. That idea gave rise to first modern tank a year later. Now, more than a century later, the logic is the same again: find a machine that can go where a soldier no longer can. A front that is too deadly. The war in Ukraine has entered a point where the simple act of sending men towards the line of contact begins to be too expensive a luxury. The saturation of drones has turned wide swaths of the front into real death zones where any movement is detected and punished almost instantly. This has changed the logic of the battle because it is no longer just about who has more armor or more artillery, but about who can continue hitting without exposing bodies. And here Ukraine is beginning to embrace a radical idea: if the front devours soldiers, perhaps the time has come to stop sending soldiers. The birth of a new “Frankenstein”. The Ukrainian response is as pragmatic as it is disturbing: take weapons systems designed for fixed positions and assemble them about ground robots. In fact, companies like Frontline Robotics They have converted their turret autonomous Buria (a kind of metal arm capable of firing machine guns or grenade launchers) into something new: small armed unmanned vehicles that act as micro-tanks. They are not tanks in the classic sense, but they fulfill part of their function. They move, shoot, seek cover and attack without a human being inside. It is a kind of improvised hybrid, a creature assembled with different parts to survive a battlefield that no longer forgives. The war against Russian infiltrations. The immediate objective of these robots is not major offensives, but something much more specific: hunt small groups of Russian infiltration. Moscow has been exploiting a simple but effective tactic for months: send small teams of infantry that slip between lines, forests and trenches to avoid aerial surveillance and penetrate Ukrainian defenses. They are small movements, difficult to detect and cheap to execute. Ukraine has understood that responding by sending more infantry only feeds that crusher. So now he sends armed robots, controlled from dozens of kilometers away, to intercept them before they go deeper into the line. The classic tank is getting old. There is a compelling reason why this idea is gaining traction: traditional tanks They are suffering greatly. Both Ukraine and Russia have discovered that a multi-million euro armored vehicle can be destroyed by a cheap drone in a matter of minutes. The economic equation has been broken. In that context, an armed terrestrial robot is a brutally logical solution: it costs less, it is manufactured faster and if it is destroyed no one dies. It is a mutation of the armored concept. Less armor, less power, less glamour… but more expendable. And in an industrial war, the expendable is often more valuable than the perfect. Evolution at the speed of war. The most striking thing is the speed with which all this evolves. Frontline Robotics It ensures that it introduces small changes up to twenty times a month and major updates every six months. The battlefield works like real time laboratory. Soldiers send constant feedback, and companies adapt their machines almost on the fly. It is a brutal advantage compared to the bureaucratic slowness of many Western industries. What today is a robot with a machine gunwithin a few months it may be a much more sophisticated system. Put another way, Ukraine is learning faster because it has no choice. Defend without humans. The underlying idea is more than a simple tactical innovation. Ukraine has already used ground robots to evacuate woundedcarry supplies, place mines and clear routes. This year they have made more than 50,000 missionsa gigantic jump compared to just 2,000 the previous semester. But what is truly new is the offensive leap: Russian positions captured only with aerial drones and ground robots, without a single infantry entering first. There has even been surrenders to machines. This paints a disturbing future: entire sectors defended and attacked by unmanned systems, where humans are increasingly distant from the point of impact. The ground war is mutating. What Ukraine is doing with these robot tanks may seem improvised, even almost artisanal, but it contains a transformation a lot more fat. For centuries, conquering land meant sending men into fire. Now start mean send machines. Not because they are better at everything, but because they are sacrificial. And on a front where every meter costs blood, the priority is no longer to advance bravely, but rather preserve lives. For this reason, Ukraine is not simply building new robots: it is testing a new way of waging ground warfare where the soldier is no longer the first piece to move. Image | Frontline Robotics, Oleksandr Klymenko/Ukrinform In Xataka | Satellite images revealed that Russia covered a building with an anti-drone cage. Ukraine turned it into an action movie set In Xataka | The drone war in Ukraine just solved an old military obsession: how to blow up a bridge without tons of bombs

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