effect

One of the most hostile places on the planet is, ironically, our best “air conditioning” against the greenhouse effect

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We knew that the Southern Ocean It is, in essence, the thermal lung of the Earth that is essential to regulate the temperature of the entire planet. But what we didn’t know exactly was how it managed to process such an amount of energy. Now, science has revealed that storms play a leading role that may be key to facing the global warming. Its usefulness. To put ourselves in context we must know that the Southern Ocean It has the ability to absorb more than 75% of excess heat that is generated by the emissions of greenhouse gases that humans themselves produce. This is something that makes it a true heat sink, potentially becoming the most important in the entire world. In this way, if we remove this Ocean from the equation of current life, the temperature of the atmosphere today would be much higher. A blind spot. The climate models that we use on a daily basis have it, since when trying to predict how water heats up, the calculations did not quite fit with what was happening in reality. Clearly, some type of element was missing here that we did not fully locate. But this has come to an end, thanks to the team led by Marcel du Plessis and Sebastiaan Swart who They have found the missing piece of the puzzle: ocean mixing driven by summer storms. A phenomenon that literally allows the ocean to ‘swallow’ atmospheric heat. How is it possible? The mechanism that this ocean follows is as violent as it is efficient. During the southern summer, the sun heats the surface layer of the ocean, and if the water remains stagnant, then the heat will remain on the surface stored in the water, making it easier for it to return to the atmosphere or accelerate the melting of ice. The correct thing to do in this case would be to literally bury it in the depths. And this is where storms come in, where the intense winds and extreme waves that are produced act like a giant mixer. In this way, the energy of the storm agitates the water, pushing heat from the surface into much deeper layers. Towards the depth. In this way, storms help the surface of the ocean cool, which gives it the ability to continue absorbing heat from the air in a more efficient way. And where does all this energy go? Well literally, When you go down to the deep sea you are ‘trapped’ there for decadesslowing down immediate atmospheric warming. Although we must keep our eyes on what will happen in the future. How it has been measured. This is a practically obligatory question when we talk about the deep sea, which are truly hostile places for anyone. That is why our best ally has been marine robotics. Instead of relying on satellites that have difficulty seeing through clouds or measuring depth accurately, this technology transferred to underwater gliders and autonomous buoys are capable of measuring temperature and salinity in real time. All this while a storm is passing over them, causing the phenomenon that has now been studied. In this way, this technology has given us the ability to monitor the ocean “from within” during events that are impossible to study on ships. We care (a lot). This discovery can be compared to that of a coin with two sides. On the one hand, we already have confirmation that the Southern Ocean is a very powerful ally in the fight against climate change. But on the other hand, we have a very disturbing question: what will happen if storm patterns change due to climate change itself? If the storms move or lose intensity in this area, we could lose this “sponge” of heat that is slowing climate change. The consequences would be quite clear: a large increase in the temperature of the atmosphere that would be felt throughout the planet. Images | jean wimmerlin Chris LeBoutillier In Xataka | We have known for 25 years that we were going to exceed 1.5 degrees of temperature increase and we have not cared

“Why the ‘rebound effect’ has become the surgeon’s best ally against Ozempic

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In the last two years, the GLP-1 receptor agonists like for example Ozempic either wegovy have gone from being drugs for diabetes to becoming the cultural and medical phenomenon of the decade for fight obesity. And such was its impact, that it was thought that surgery for obesity had come to an end, but the reality has been very different. The premise. The idea is quite clear: if I can take medication twice a month to lose weight… Why would I go into an operating room? A logical idea, especially given the risks that one always has when entering surgery, no matter how well controlled they are. But this enthusiasm of abandon the scalpel It is slowly being diluted, since according to the latest research, bariatric surgery is still superior to GLP-1 agonists and achieves much better results. The devastating fact. The study that has shaken the board comes from NYU Langone where researchers compared patients undergoing interventions such as gastric bypass with those who had taken Ozempic. The result was quite clear. Those who had undergone surgery managed to lose between 24 and 26% of their body weight, while patients on drugs lost an average between 5 and 6%. A result that does not agree with what was expected by pharmaceutical companies with their clinical trials in hand. But the problem is that the variable adherence to treatment It is once again a big problem in medicine. More data. The University Clinic of Navarra He also wanted to investigate in this field, doing a large study with 20,000 patients, concluding exactly the same thing: bariatric surgery surpasses GLP-1 agonists in total weight loss, reduction in BMI and body composition. The human factor. The great failure of a pharmacological treatment is undoubtedly the humans who are going to take it. And it is quite common in medicine for patients to forget to take a dose of their medication or even abandon treatment halfway through without any type of control. But luckily, the big difference between a pill (or injection) and surgery is that the second cannot be “forgotten.” The studies are clear in this sense: between 60% and 70% of patients They abandon GLP-1 treatment before the first year. Something that causes a great rebound effect which makes a patient return to their original weight, especially if they return to the same eating habits as before starting treatment with Ozempic or others. The difference. The reasons for reaching this point in treatment are varied: from persistent gastrointestinal side effects to the high monthly cost of treatment or the shortage. But the thing is that while stopping pricking yourself causes a rebound effect, bariatric surgery, although invasive, offers much more stable long-term results. Although logically he has many other problems behind him. Beyond the scale. The superiority of surgery is not measured only in waist centimeters. Science points through a systematic review published in JAMA Network Open This 2025 suggests that surgery is associated with lower overall mortality and a more drastic reduction in major cardiovascular events compared to drugs. And although GLP-1 has shown great benefits, the truth is that science indicates that surgery is still better in remission of type 2 diabetes with a minimal risk of mortality. Furthermore, despite the initial cost of the operation, in the long term surgery is cheaper for health systems than chronic drug treatment that costs hundreds of euros per month for life. A combined therapy. Despite all this, we are not in a war of one against the other, but the future points to an integration of both elements. In this way, strategies are already being explored where GLP-1 is used before surgery to reduce surgical risk in patients with extreme obesity, or after surgery as a rescue tool if the patient begins to regain weight years later. Even the WHO has begun to include these drugs in its comprehensive treatment guidelines, but emphasizing that they are one more piece of the puzzle, not a universal substitute. Images | David Trinks In Xataka | We have more and more research on the effects of Ozempic. And the problem is that we have more and more doubts

Spain needs to modernize its electrical grid, so the remuneration rate has increased. The effect will be noticeable in the next five years

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Until now we have observed the electricity bill as has increased after the April blackout. But this time the focus is not on the receipt, but on a silent decision that the National Markets and Competition Commission (CNMC) has just made and that will determine how much it will cost to keep the light on in the next five years. Piecemeal. The CNMC has sent to the Council of State the circulars that establish how the transport and distribution of electricity is remunerated between 2026 and 2031, the so-called “network business”: the towers, cables and transformation centers that make it possible for energy to reach homes, factories and hospitals. The technical detail is a figure: 6.58%. This new percentage – up from 5.58% – is, according to the regulator, an update that better reflects current financial conditions, after a period of rising interest rates. However, the measure is far from the 7% or 7.5% requested by the large electricity companies grouped in Aelec (Iberdrola, Endesa, EDP and Naturgy) and that the small distributors represented by CIDE also claimed. And in the pocket? Good question. These circulars, which will come into force on January 1, 2026 if the Council of State does not introduce changes, define the remuneration criteria for the entire period 2026–2031. In the short term, the increase will not be directly noticeable on the bill, but it will influence the regulated costs that support the electrical system and that we all pay. According to CNMC calculationsthe impact of the change will be between 0.9% and 1.1% of the total annual costs of the system, depending on the level of investment. The purpose of this rate is to guarantee that companies that maintain and expand the electrical network receive a reasonable return on their invested capital. If the percentage is too low, investment is discouraged; If it is too high, the costs of the system and, in the long run, the consumer’s bill increase. The regulator look for a balance point: enough attractiveness for lines to continue being built and reinforced, but without transferring an extra cost to homes. A change in calculation. For the first time, historical data and future forecasts will be combined to estimate the cost of companies’ debt, rather than relying solely on past interest rates. New components are also incorporated: transaction costs (such as commissions for issuing debt), the so-called cost-of-carry (cost of maintaining financial positions) and a correction due to the European Central Bank’s bond purchase programs, which had artificially reduced the profitability of public debt and, therefore, the risk-free rate. According to the organizationthis is a “more realistic” methodology that incorporates recent market volatility. The change will be applied in a phased manner during the six years of the new regulatory period and expands the margin of recognized investment, including not only new infrastructure but also improvements and optimization of existing ones. The goal: keep bills contained while the network is modernized. The “K parameter”. Beyond the technicalities, what is at stake is Spain’s ability to electrify its economy without skyrocketing the bill. The CNMC has set it at 257 euros per connected kilowatt, compared to 232 euros in the previous draft. The companies maintain that the real cost is around 375 euros/kW, so the improvement falls far short. This parameter determines how many industrial projects, data centers or new homes can be connected to the network without the connection being economically unfeasible. According to the employerlimiting remuneration to that level “prevents connecting part of the new consumers” and can put the competitiveness of entire sectors at risk. This has been the response. Aelec expressed its “deep concern” and warned that the new circulars “compromise the electrification and industrial development of the country.” The employers insist that the rate is still below European levels – between 6.8% and 7.5% – and warns that “it discourages investment just when the country needs to deploy more electrical infrastructure.” More than 67 business and social associations have joined his call. In a manifesto cited by Aelec itselfwarn that, if conditions are not reviewed, “the Spanish electricity networks could collapse.” The employers’ association also criticizes that the CNMC has reduced the recognized maintenance costs by 37%, which, in its opinion, may deteriorate the quality of the service and stop the connection of new clients. For its part, the CNMC maintains that its obligation is to protect the consumer and guarantee the sustainability of the system. The organization seeks to “limit the impact of investments on customer bills” and remembers that everything that electricity companies invest in these networks is paid as fixed charges on the electricity bill. The balance, the regulator insistsconsists of remunerating the necessary investments without overloading the end user. A decision with long-term effects. Behind this technical dispute lies a fundamental question: can Spain electrify its economy at the necessary pace without increasing the remuneration of the networks? The Government has launched a plan to increase investment in networks by 62% until 2030, with around 13.6 billion euros to reinforce the national network, as El Economista recalled. However, Five Days points out that the new limitations of the CNMC could stop part of these projects and leave out consumers with higher connection costs. The electricity companies are now preparing allegations before the Council of State, while the regulator defends that its proposal offers stability and predictability for six years, a rarity in a context of financial and energy volatility. An invisible, but transcendental decision. The figure of 6.58% will not say much to the average consumer, but a good part of Spain’s electrical future depends on it. It defines whether there will be enough investment to connect the new factories, electric vehicle chargers or data centers that support digitalization, and also how much each family will pay to keep that network operational. You won’t notice anything on your next bill, but this decision determines how much you’ll pay—and how reliable your grid will be—over the next five years. Between containing prices and … Read more

The Japanese Shinkansen was the fastest train in the world until China defeated it. The reason: the “piston effect”

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In a very summary way, the piston in a four stroke engine It is responsible for moving the air inside to compress it and facilitate the burning or explosion of the fuel or to push it out of the combustion chamber. That is, it is dedicated to pushing the air up or down. Now imagine a train arriving in a tunnel at more than 300 km/h. Suddenly, the train goes from being outside to moving the air inside the tunnel. To push it to the bottom. Your movement It would be very similar to that of a piston. The train moves in a straight line and around it the tunnel would behave like a combustion chamber. That doesn’t seem like a problem. It doesn’t seem like it if we think that the air is simply pushed to the outlet where it is released without further problem. It’s also not a problem if your high-speed lines run over a bridge more than 100 kilometers long. But if you are a mountainous country and you have made the railway your star medium to move millions of people hundreds of kilometers an hour. Yes, you have a problem. Because the piston effect is pure physics and solving it to gain speed is not being easy. When they were the best In 1964, while Spain began to open up to the world, Abebe Bikila won his second Olympic Marathon in the streets of Tokyo. He did it wearing Puma Osaka shoes.nothing to do with the famous 42,195 meters that he covered barefoot in Rome to win four years before. We do not know if Bikila took that first Shinkansen that linked the cities Tokyo and, precisely, Osaka. The bullet train had begun to operate in Japan that same year, promoted by the Olympic Games in the Japanese capital. Then, the two cities were linked by a train that reached peaks of 210km/hbecoming the first high-speed line in the world. More than 60 years later, Japan is no longer the country with the highest number of high-speed kilometers of the world. Today it is China. It makes sense, taking into account that the country is huge, so if this means of transportation were promoted, sooner or later they would surpass their neighbors. Spain, by the way, also surpassed Japan in this area years ago. But it is very likely that something else has hurt Japan more. China is making the bullet train its flag. Its latest advances with the maglev, which levitates thanks to very powerful magnets to avoid friction with the track, has reached a combined speed of 896 km/h at the intersection of two CR450 trains. The problem for Japan is that China has a lot of money. And if it is necessary to build eight of the 10 longest bridges in the world to solve geographical accidents, they get to work. Japan has to deal with a lot of mountains and a more traditional system: tunnels. And that when you want to make a train pass at very high speed is quite a problem. When a train fully crosses the threshold of a tunnel, what is known as piston effecta problem that prevents increasing the walking speed further. The consequences are as simple as they are serious: loud explosions, breakage of equipment… and the eardrums of passengers. Upon entering the tunnel, the air is compressed and the movement of the train moves it towards the exit. However, some of that air rebounds and generates pressure changes that can be especially painful for passengers, even affecting their middle ear. When moving outside, a pressure wave is created that moves at the speed of sound and when the train leaves the tunnel, a shock wave and a sound explosion are created that, it is calculated, can be heard 400 meters away. It is known as tunnel boom. Japan is now experiencing a problem carried over from the past. Their trains are wider than the European ones but their tunnels are narrower. This was to reduce infrastructure costs but also to run less risk of landslides in the event of an earthquake. At first this was not a problem but when the speed of the trains increased they realized that they could not continue moving. In China, trains also use wide tracks like their neighbors but since they do not preserve inherited structuresthe new tunnels built are wider. This reduces the void effect produced with the entry of the train into the tunnel and, therefore, mitigates the problems for passengers. Furthermore, as less resistance is generated when the train passes, energy expenditure is also reduced. The solution for the Japanese is not simple. On the Tokaido Shinkansen, the first high-speed line (the one that connects Tokyo with Osaka), 13% of total kilometers They run inside tunnels. But the Sanyo Shinkansen line runs through tunnels half of the time. and he Hokkaido Shinkansen which is under construction (this line is only partially open) contemplates the roofing of 80% of the layout. The most effective solution that has been found to the problem is to produce trains with a very long and sharp nose. The aerodynamics tries to imitate the beak of the Kingfisher that can dive into the water generating minimal splashes. Following the same concept, the longer and sharper the nose of the train, the less resistance the train encounters at the entrance and the more gradually the pressure wave is generated. The other solution has been expand the section of the tunnel at its entrance. The “door” is wider and also has side openings that allow part of the air to escape. air moved by the train. This escape route generates a lower pressure wave, allowing the train not to cause unwanted discomfort to passengers and to travel faster. It has even been thought of hermetic trains with controlled pressure. During its tests, Japan continues to search for trains that can reach a top speed of 400 km/h. However, the structures inherited from … Read more

How to see any photo with the 3D space effect of iOS 26 on your iPhone using the new function of the APP photos

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Let’s explain How to use the app Photos From your iPhone to see with 3D effect The photos you want. It is one of the functions of iOS 26 with which you can use this effect with your photos On the lock screenbut the APP photos also allows you to use it with anyone at any time. Here, you just have to know that this function is pure amusement, to see the effect and that’s it, you can’t use it for much more. But in the end, it can also help you to see how you are with any photograph you have before using it then as a wallpaper. Use the spatial effect with any photo The first thing you have to do is Open the application Photos On your iPhone. Remember that you should have updated iOS 26, and the condition is that the photo where you want to apply the effect must have some type of protagonist, such as a person, pet or object. Choose a photo and enter it. Once you are inside the photo, you have to click on the hexagon icon that will appear above right. To see it you must have the interface, that is, if you only see the photo click on the screen so that the other elements come out. When you press that button, you will see that for a few seconds some purple colors appear on the screen while the AI ​​analyzes the content of the photo. Then you will see that The indicator of Space sceneand that when you move the mobile screen you can see the 3D effect of the photo. In Xataka Basics | How to obtain information from what appears on your iPhone screen with Apple Intelligence and iOS 26

They have studied the effect of long -term sweeteners on our brain. His conclusion is that he ages faster

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Little by little it is already becoming a daily gesture among many people: change sugar for a sweetener to avoid calorie consumption in excess. Whether in the morning coffee, in a yogurt or in a refreshing drink, sweeteners are attractive to respect the sweet taste and ‘be healthy’. However, a new and forceful study Posted in the prestigious medical magazine Neurology He puts this idea in check, suggesting that this substitution could have a long -term hidden cost for our cognitive health. A direct effect to thought. Research, which has established itself as one of the broadest and most prolonged to date on the subject, cooks that people with high consumption of sweeteners such as the aspartamosaccharin or sorbitol They experience a deterioration of their thinking and memory capabilities 62% faster than those people who consume. To put it in perspective, the researchers calculate that this accelerated decline is equivalent to aging 1.6 years suddenly. The details of the study. It is not a PSAJERA survey or a small -scale experiment. Scientists have been based on the Brazilian Longitudinal Health Study data of the adult (Elsa-Brazil), a mass and long-distance research project. They analyzed a cohort of 12,772 public officials with an average age of 52 years, which were followed for eight years, and with analysis at three different moments: 2008-2010, 2012-2014 and 2017-2019. Detailed questionnaires. Using food frequency questionnaires, the team quantified the combined and individual consumption of seven specific sweeteners: artificial ones such as aspartamo, saccharin and acesulfamo K, and sugar alcohols such as erythritol, xylitol and sorbitol, in addition to the tagatose. In parallel, the cognitive performance of patients with a six -test battery that focused on memory, verbal fluidity and global cognition was measured. The results. The consumption of sweeteners, both individually and combined, was associated with accelerated cognitive loss. The ‘suspect’ list includes some of the most common names we find on the labels of ‘Light’ products or ‘zero’: aspartamo, saccharin, acesulfamo k, erythritol, sorbitol and xylitol. Interestingly, the trend was more pronounced and statistically significant in participants under 60 years. This suggests, according to the authors, that median age is a critical window where the products that are chosen consumer may have direct consequences in brain health decades later. The researchers They point that until now the sweeteners without calories often “are seen as a healthy alternative to sugar.” But now it has been seen that great consumption of these has “negative effects on brain health over time.” There are limitations. The researchers themselves suggest that dietary data are based on self -reports, which can be inaccurate, and that, despite statistical adjustments, the “residual confusion” cannot be completely ruled out where other nutritional behaviors that may be interfering are not measured. Correlation is not causality. As expected, this study can generate a great debate, and the industry and the scientific community have called for prudence, remembering that correlation does not imply causality. Gavin Partington, general director of the British refreshing drinks association, and the International Association of sweeteners (ISA) They have pointed out that this is an observational study. That is, it finds a statistical association between two variables (consumption of sweeteners and cognitive impairment), but cannot demonstrate that one is the direct cause of the other. In Spain, experts such as neurologist Guillermo García Ribas, from the Ramón y Cajal hospital, They are cautious. He criticizes that it is difficult to isolate the effect of the sweetener of the rest of the diet. Often, a high consumption of these products goes hand in hand with a diet rich in ultraprocessed foods, which have already been linked in numerous studies to a worse cognitive aging. The defense of researchers. Anticipating this criticism, the Suemoto team offers two solid arguments. First, they observed that the association was also maintained for individual sweeteners, those that a person adds on their own to coffee or yogurt, and not only for the compounds used by the industry in the ultra -processed. Second, and perhaps more important, there is what scientists call “biological plausibility.” Previous studies carried out in animal models (mainly mice) have already shown that artificial sweeteners can trigger neuroinflammation processes and alter the crucial intestine-cerebro axis, mechanisms that could negatively affect brain function. The global context. This study does not arise in a vacuum. It adds to a growing wave of skepticism on the long -term benefits of sweeteners. In fact, in 2023, The World Health Organization (WHO) itself advised the use of these products to control the weight or reduce the risk of chronic diseases, arguing the lack of evidence on its long -term benefits and the existence of possible unwanted effects that had not yet been completed. The underlying problem remains the same: excessive sugar consumption. In countries like Spain, the maximum daily amount recommended by WHO is tripling. The sweeteners emerged as an apparent solution, but studies like this force us to ask ourselves if we are simply changing one problem for another. As Suemoto himself summarizes, his work “adds solid evidence that these compounds may not be harmless, especially when consumed frequently from the median age.” The conclusion is not that we should return to sugar, but that we must examine much more critically with what we are replacing it Images | Towfiqui Barbhuiya In Xataka | 9 questions and answers about Estevia, the fashion sweetener

August has been an extremely warm month in Spain. That has had a side effect: make us older

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This summer has left repeated scenes: empty squares at the time of the nap, nights in the heat and a Mediterranean turned into a pressure pot. Spain has suffered suffocating days They will go to statistics, but the most serious is not measured in degrees. According to a recent study, heat waves do not leave when the temperature drops. They leave a silent trail in the body: they accelerate biological aging. A disturbing finding. A recent study Posted in Nature Climate Change It has shown that repeated exposure to heat waves accelerates biological aging. The work, led by the University of Hong Kong, followed 25,000 people for 15 years in Taiwan. The results speak for themselves: four extra days of heat wave in a period of two years were translated in nine days added to the biological age of the participants. In manual workers, more exposed to the sun and heat, that effect shot up to 33 days. “The impact of heat on our body is comparable to tobacco, alcohol, poor diet or lack of exercise,” The research team has summarized to The Guardian. The biological clock under pressure. How did they get to that conclusion? The scientists calculated the biological age from different markers: blood pressure, inflammation, cholesterol and the functioning of lungs, liver and kidneys. When comparing them with the real age of each person, the conclusion was clear: who had spent more time under heat waves showed accelerated aging. The exact reason is still unknown. The main hypothesis is that high temperatures damage DNA and submit the body to constant stress. “If the exhibition accumulates for decades, the impact on health will be much greater than we have now measured,” has pointed to The Guardian Dr. Cui Guo, main author of the study. More evidence: heat at all ages. This finding does not come alone. In 2024, another job Posted in Nature He revealed that early exposure to cold and heat interferes with the development of the white matter of the brain in children. The consequences, the authors warned, could extend throughout life. The conclusion is clear: heat does not understand ages. Inference affects developing brains; In adulthood, it accelerates the organism’s wear. Can the damage be stopped? The same study offers an interesting nuance: the harmful effect seemed to be reduced over time, probably because people learn to protect themselves better. Searching for shadow, hydrating or using air conditioning made a certain difference. Even so, the biological footprint never disappeared completely. The problem is that not everyone has the same possibilities to adapt. Older people, outdoor workers or those who live in neighborhoods with less resources suffer a much greater impact, As the study collects. Prevention, experts coincide, goes through reinforcing Urban design: More trees, more shadow, better isolated homes and just access to cooling. Individually, recommendations remain simple but effective: hydrate, avoid hours of heat and seek refuge in fresh places. The invisible heat scar. Until now we thought about heat as something passenger: annoying, exhausting and dangerous in extreme days. But scientific evidence points to something more disturbing. The heat, the experts say, does not leave at all when the thermometer goes down: it stays inside, accelerating the wear of the organism and leaving an invisible scar. For researchers, this finding is a turn in the way of understanding health. And the warning is clear: if the planet continues to heat up, we will not only have longer summers, also bodies that age faster. Image | Unspash Xataka | The sea is 30 degrees in the Balearic Islands and that worries meteorologists: the Mediterranean is a pressure cooker

The effect of heat on our heart rate when playing in summer

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It is the summer stamp: go running or riding by bike and, a few minutes later, the pulsometer is triggered to figures that do not correspond to the effort. And it’s not a strange thing to see. It is the body that is trying to respond to a series of stimuli such as heat and exercise, and understanding its physiology is important for Do not turn sports into a health risk. Exercising in summer is a great challenge. In this situation the body is forced to respond to two specific demands. On the one hand, Muscles in action need a lot of energy in the form of ATP To contract. However, this is an inefficient process, since It only takes advantage of between 20 and 25% of the ‘produced’ energy releasing the remaining 80% in the form of heat. This energy in the case of not dissipating it correctly can raise internal body temperature by 1 ºC every 5-10 minutes. How to avoid it. On the other hand, to avoid precisely that lethal overheating, the body thermoregulatory center located in the hypothalamus, Activate powerful cooling mechanisms. One of them is to pump huge volumes of hot blood from the body nucleus to the skin, causing it to be red by that large amount of blood that is going through the surface of the body. This double duty is the fundamental reason why the pulse shoots and becomes the most sensitive and critical indicator of the stress to which the body is subjected The organism has to compensate. These two situations cannot be carried out in parallel, but A balance must be achieved. And it is that when the system is taken to the limit by the intensity of the exercise and the severity of heat, something has to yield. Or blood flow is reduced to the muscles, limiting the ability to maintain rhythm, or the flow to the skin is committed, limiting heat dissipation and increasing body temperature to dangerous limits. Understanding this internal negotiation is key to understand why training in summer is much more than a simple matter of willpower. The skin becomes a giant radiator. The first and most powerful response of the body to the increase in skin temperature and body nucleus It is body vasodilation. Controlled by the ‘thermostat’ of the body, the preoptic area of ​​the anterior hypothalamus, this mechanism causes the blood vessels close to the skin to widen and make it become a refrigerator. Under resting conditions and neutral temperature, the cutaneous blood flow is just about 300 ml/min. However, during an intense exercise in a hot environment, this flow It can shoot until reaching 7 or 8 liters per minute. Something that also represents around 50 and 70% of all cardiac output. And this is a simple deviation of resources with the objective of dissipating heat by convection and radiation. Although it is not free. It has an important cardiovascular cost. The heart accelerates to compensate. The fact of opening the ‘pipes’ that lead the blood to the skin causes the heart to have to activate an important compensation mechanism so that the organs remain perfused. We talk about heart rate, which will be increased. The objective is to maintain cardiac output, so that blood pressure is stabilized despite the low peripheral resistance due to vasodilation. A crucial aspect of this process is speed. The initial increase in heart rate is an incredibly fast neural reflex, triggered by Thermal skin receptors. This response often precedes any significant increase in central body temperature. This shows that the body not only reacts to heat, but anticipates it, preparing the cardiovascular system for the thermoregulatory battle that is coming. The key is in cardiovascular drift. Any athlete who trains with a pulsometer in summer will have noticed a disconcerting phenomenon: even maintaining a constant rhythm, the pulse tends to rise progressively throughout the training. This is something that has been documented and called ‘cardiovascular derives‘, which is defined as the gradual and continuous increase in the heart rate that occurs during a prolonged exercise of constant intensity, accompanied by a decrease in systolic volume (the amount of blood that the heart pumps in each beat). And precisely the heat stimulates the two mechanisms that drive this phenomenon: The increase in skin flow by vasodilation. This causes blood to ‘stagnate’ temporarily on the periphery, which reduces venous return. This means that the heart does not fill so much in each beat, and therefore the amount of blood that will expel will be less. Dehydration Sudoration is essential to cool the complete system, but it entails a loss of body fluids, mainly from the blood plasma. This again reduces that the blood returns to the heart so that the same volume can be pumped. And to compensate the only thing left is to increase the heart rate. The pulse increase per centigrade grade. Once the ‘why’ of this increase in heart rate is known, an athlete is interested in knowing the ‘how much’. And the reality is that studies have established a very useful general rule to know how our body temperature increases when exercising: In dry heat conditions, with environmental temperatures above 24 ° C, the heart rate Increase approximately one beat per minute for each celsius degree of temperature increase. In wet heat conditions, the impact is multiplied. Here the increase in heart rate triggers between 2 and 4 beats per minute for each degree Celsius that increases the ambient temperature. This difference is not trivial. Exercise at 34 ° C in a dry climate (10 ° C above the threshold of 24 ° C) could involve an increase of about 10 beats per minute in the heart rate for the same effort. On the other hand, to those same 34 ° C, but with a high humidity, the increase could be 20 to 40 beats per minute. This additional load on the heart explains why we call as ’embarrassing’ feels much more … Read more

The urban heat island effect

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Summer is here and with him the desire of millions of people to escape the city. The east desire is more than the mere enjoyment of the beach, leisure or rural landscapes, there is also the prevailing need for escape heat. And part of the fault of this lies in the so -called urban heat island effect. What is the urban heat island effect Heat island? The term refers to the fact that cities They tend to accumulate heatwhich implies that the temperature in them is usually higher than in their surroundings. This effect can be felt during the day but it is perhaps at night when the difference between urban temperature and that of its surroundings is greater. The difference can be several degrees. An estimate For example, he calculates that the difference between New York City its surroundings is around the 4th Celsius. A recent study made in five Spanish cities estimated that the average variation in Madrid was 1.3º, but in Valencia reached 4.1. The responsible team came to measure differences of up to 11 between the center and the periphery of the Spanish cities studied. How a heat island occurs The causes of the heat islands There are several and diverse. The construction materials we use tend to absorb energy that they release during the night. This makes night temperatures do not descend in the city as much as in other contexts, thus accumulating heat. The buildings, in addition, block the passage of the air that would drag the heat accumulated in the day to day, while the absence of trees and of phenomena such as the evaporation of soil water contribute to a worst thermoregulation of the system. The other great factor responsible for urban warming is human activity. Many of our activities, from driving to heating a pout generate residual heat. Even when we cool things, for example when we use the air conditioning, the thermal “balance” is positive. What factors aggravate the problem We pointed out before not all cities experience a heat island of the same magnitude. The complexity of the factors that cause this phenomenon is responsible for it. Knowing this, we can list some factors that can influence the degree in which a city stands out from its thermal environment. Among these factors We could find Population density, orientation and structure of its street, characteristics (height, materials) of its urban buildings, vegetation and trees, the passage of rivers, or its location with respect to geographical elements such as the mountains or the coast. Even the color of the buildings, including its roofs, affects the temperature differential. The heat island in the city of Paris. Copernicus Climate Change Service, ECMWF. Consequences of the heat islands The direct consequence of this phenomenon is an increase in temperatures, which in turn affects a multitude of Aspects of everyday life of whom these cities inhabit. Both at night and day. Heat can have consequences on our health and well -being: heat strokes, Difficulty reconciling sleep or to concentrate or an increase in the risk of suffering the effects of certain diseases such as cardiovascular, among other problems. Urban heat can be somewhat positive in winter or certain climates from the energy point of view, but in summer it will imply that we will spend more to cool our homes, work areas and even our refrigerators. A problem that will go to more There are two factors that invite you to think that this phenomenon and its consequences will go worse in the coming years. The first, climate change. Perhaps the phenomenon that we mostly associated with climate change is the increase in the average temperature of the planet. This temperature increase can be added to the increase associated with urban heat island, thus increasing the risks and problems associated with this phenomenon. The second factor to consider are migrations, specifically the rural exodus. A growing proportion of people live in cities, some of them already host dozens of millions of people. The biggest cities They are more susceptible to suffering the problem of urban heat island. In addition, the more people live in them, the more people the impacts of this temperature increase will be vulnerable. How to prevent the heat island effect Urbanization is a process that continues, especially in the “developing” countries, so all we can do is search ways to reduce impact of these heat islands. To do this, understanding its causes and dynamics is essential. The solutions that They have been proposed To avoid heat accumulation in cities are diverse, but the possibility that they can be implemented depends on various factors. For example, in an area still under development, we can encourage architectures that optimize air flow and reduce the presence of materials that capture heat easily. It is also important to leave spaces to non -urbanized areas, natural and seminatural environments such as parks and urban forests. The introduction of trees and other green areas () can also be feasible in already built areas. The mere Presence of trees On an avenue you can significantly reduce the insolation that reaches the ground and thereby prevent it from hot as much as it would happen without the trees. In this sense, even the use of paintings that increase the solar energy reflected again to the atmosphere (if we paint a roof or a white square, for example) it can also become a useful resource. In Xataka | An American city is “terrifying” its streets to combat heat. They have an ally: NASA Image | Fabian Lozano

If you have the feeling that everything is more expensive than ever, it is not your imagination: it is called “Zillow effect”

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Digital platforms promised to make everything easier and cheaper. Actually, they have created the opposite phenomenon: The “Zillow Effect” is taking practically everything What we play online, whether digital or not. Why is it important. When any transaction is digitized, the demand is triggered because it eliminates friction, but the supply remains constant. The result is usually the same: prices go up and competition intensifies for buyers. The panoramic. The effect began in the real estate sector with Zillow in the United States, A real estate platform born in 2006 which allowed anyone to consult the value of their home. Now it extends to university candidates, employment searches, appointment applications, concert tickets, vacation destinations and even second -hand markets. If you can buy it with a click, it is probably more expensive than before. In detail. The mechanism is simple: Before, requesting place at a university required physical effort. Get forms, send them by postal mail, go to pay fees. Now, with a button you can send your application to twenty universities. Result: the best receive many more requests, they can be more selective and the competition to access goes up to the same pace that their access barriers are lowered to the application. The same happens in the labor market: For candidates, there is a paradox: getting a job becomes more complicated. The contrast. There are two large categories of products here: Products with elastic offer. They are the ones that can be manufactured in greater quantities. Clothing, processed food, smartphones. They have been cheaper. Products with limited offer, or by regulation or by their own nature. Housing in good areas, places of universities, more desirable jobs, very attractive sexual couples. They have fisher, financially or symbolically. Between the lines. Great technology benefit from this problem, so they have no incentive to solve this problem. More demand is equivalent to more data, more engagementmore commissions. The case that gives name to this effect has a perfect example: Zillow earned money both if the houses were sold as if notbecause he charged for teaching them. AND Your platform fired your visibilitywith the aforementioned consequence: same supply, greater demand … upward prices. The threat. The Zillow effect has as first victims local and imperfect markets where opportunities could be found before. There are no longer the secret restaurants, virgin and quiet holiday destinations, or jobs that only a few knew. Google Maps, LinkedIn, Instagram or YouTube have democratized knowledge, but have also concentrated demand. An example: Instagram and ‘Tourism of Likes‘. And now what. A possible solution would increase the offer where possible, such as building more housing or creating more university places. Another would artificially limit digital demand. But there are not too many incentives for it. The digital world has connected us in this century, but it has also put us to compete against many more people for the same limited resources. And there is only a great winner: the platforms. In Xataka | 34 futuristic predictions made in the past: erroneous, successful and crazy Outstanding image | Xataka

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