Sergio Parra

Many book lovers still prefer the traditional paper book option over an ebook. They value the tactile feel of a bound paper book. Paper books are, as a rule, very well designed, smell good, and they carry with them a more human touch.

A paper book provides a more intense psychological sensation of possession. You possess the book as an almost totemic object. In an ebook you only use the book. But beyond the romantic halo, there is a practical reason (and scientific) why it is inadvisable to read ebooks before going to sleep (at least some types of ebooks).

Backlight and melanin

High levels of screen brightness on an electronic device can contribute to eye strain, a condition characterized by tired, itchy, and burning eyes.

In Xataka Science

Reading a book is not the same as listening to an audiobook: commitment, understanding and presence of the narrator

Also there are potential considerations for those who read e-books on light-emitting e-readers at night (although some e-readers do not use light-emitting screens). Exposure to artificial light from light-emitting e-readers may interfere with users' ability to sleep and ultimately generate adverse health effects.

A 2014 study published in the magazine PNAS Thus, it suggests that reading an ebook before going to bed decreases the production of melatonin, a hormone that prepares the body to sleep. E-books had also affected the reader's alertness the next day.

In Xataka Science

Reading radically transforms our brain

Reading is unnatural because the natural state of the human brain, as well as that of most primates, tends to be distracted. However, reading a book requires intense concentration for a long period of time. Doing it on paper is as unnatural as doing it on an ebook, but it seems more convenient to do it (at least for now) on paper.

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If you are going to read a book before going to sleep, it better not be an ebook.

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Sergio Parra

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He Ursus maritimus tyrannus It measured 1.83 meters and had an average mass of more than a ton (1200 – 1500 kg), making it almost three times heavier than an adult male brown bear.

This fossil subspecies evolved from an isolated population of Arctic brown bears in the late Pleistocene and It was the largest carnivorous land mammal of all time.

Since the oldest fossil is 100,000 years old, it is estimated that they evolved between 100,000 and 250,000 years ago, from a population of Arctic brown bears, probably isolated by glaciation.

Evolution

The contemporary descendant of this enormous creature is the largest bear today, the Polar Bear: The adult male has a mass of 400 – 600 kg and measures up to 2.6 meters in length from nose to tail.

The species lives in latitudes 65 – 85º N, making it the northernmost bear.

Also in the terrestrial mammal with a more extensive habitat: Adult polar bears in Hudson Bay, Canada, have vast territories of up to 350,000 square kilometers, approximately the size of Germany.

In Xataka Science

Global animal populations have declined by an average of two-thirds in less than half a century.

Under the fur is the skin, which is black to better attract solar radiation and thus increase body heat. Ordinary light reflects on the fur, normally generating the false sensation of whiteness. Nevertheless, At certain times and places it can appear yellowish or even light brown.

By the way, The most nutritious bear milk is also that of the polar bear: contains up to 48.4 % fat and is vital for bear cubs, which must survive in a frigid environment.

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This was the largest bear of all time and had a mass of more than a ton

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Sergio Parra

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A team of researchers has studied brain aging measuring the volume of the cortical mantle and hippocampal regions of the brain provided with MRI scanners of more than 2000 participants.

These areas of the brain are prone to shrink over time, as a natural part of aging. The brains of the participants were scanned up to three times over a period of 11 years, thus being a large-scale longitudinal test, one of the largest of its kind.

Brain shrinkage

The researchers compared the rate of reduction in these areas in people who had obtained higher education before age 30 and those who did not. Participants were between 29 and 91 years old.

What they concluded is that higher education is modestly related to larger brains.

In Xataka Science

How the secret language of neurons was discovered and the first person who could hear it

While the rate of brain change was similar in participants with and without higher education, the researchers found that those with higher education had slightly larger cortical volume in some regions, but even in these regions, the rate of change was not related to education.

In conclusion, the human brain shrinks. Even in healthy individuals, those who do not suffer from any neurodegenerative disease, or those who have higher education, this gradual reduction in size is recorded from the age of 25 and the process accelerates after the age of 50. This atrophy is mainly localized. in the frontal lobe and the hippocampus, the area where memories are fixed, so that it has direct consequences on faculties such as our ability to reason, mental speed or episodic memory.

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No, having higher education does not influence how the brain ages

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Sergio Parra

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With the first evidence of fire use or tool making, the Wonderwerk Cave in South Africa hIt has been confirmed as the oldest human-populated cave in the world, according to a new investigation published in Quaternary Science Reviews, led by a team of geologists and archaeologists from the Hebrew University of Jerusalem (HU) and the University of Toronto.

axes and fire

The study establishes the change from Oldowan tools (mainly sharpened slabs and cutting tools) to the first hand axes more than 1 million years ago, and the deliberate use of fire by our prehistoric ancestors 1 million years ago, in a layer deep in the cave.

Additionally, Wonderwerk contained a full range of fire remains: burnt bones, sediments and tools, as well as the presence of ashes.

As explained by the main author, Professor Ron Shaar from the HU Institute of Earth Sciences:

In Xataka Science

The largest "Stone Forest" in the world is located on the oldest island in the world

We can now say with confidence that our human ancestors were making simple stone tools inside Wonderwerk Cave 1.8 million years ago. Wonderwerk is unique among ancient Oldowan sites, a type of tool first found 2.6 million years ago in East Africa, precisely because it is a cave and not an open-air occurrence.

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It is confirmed that this is the oldest human-populated grotto in the world and is in South Africa

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Sergio Parra

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Traditionally, the golden rice, because it is a genetically modified organism, has entailed fierce activist resistance from a certain ideological spectrum.

You will have to ask them what do you think about this: yeast pills designed with genetic engineering that settle in your intestine and They synthesize vitamin A from what you eat (something that could happen soon given the results obtained in mouse models).

Transgenic yeasts in mice

Most yeast species cannot survive in the intestine of mammals: Heat and acidity are beyond your tolerance limits. But Saccharomyces boulardii It not only grows easily in the intestine of mammals, but also inhibits pathogenic intestinal infections in the mammalian host.

In Xataka Science

Transgenic salmon can now be purchased in Canada

Like golden rice, it is a transgenic variety that can fill vitamin A deficiencies, maybe one day this yeast can do it more effectively.

In a new step for synthetic biology, a group of researchers has opened new biosynthetic pathways in S. boulardii that allow the production of vitamin precursors (such as beta-carotene, a precursor of vitamin A) and drugs (such as violacein, a natural drug with anti-inflammatory properties) in the intestine of mice. They thus demonstrated CRISPR-mediated genome editing with high efficiency (95%) in this yeast strain..

In Xataka Science

Campbell's Soups are proud to label their products as GMO

The researchers reported that S. boulardii formed stable colonies in germ-free mice for more than 30 days, competing for space with other gut-resident microbes.

The researchers then tested the modified S. boulardii in the mouse model and found that the yeast cells successfully synthesized beta-carotene in the intestine of mice. By comparing the total mass of additional beta-carotene recovered in feces to the beta-carotene present in the initial dose of probiotics, the authors estimated that the germ-free mice produced 194 micrograms of beta-carotene in approximately 14 days.

In Xataka Science

This genetically modified rice will not only combat hunger but also climate change

This proof-of-concept study inspires further questions about the amount of beta-carotene absorbed by the mice, the biological relevance of the amounts produced, and, most importantly, If the process can be replicated in humans. Be that as it may, I'm sure Greenpeace is against it..

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If you don't like golden rice to produce vitamin A, you may prefer transgenic yeast that settles in your intestines

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Sergio Parra

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Fly is the common name of various species of flying insects belonging to the order Diptera (Diptera): there are more than 120,000 different species.

But, despite their size and the fact that they usually only constitute a nuisance during the summer, These creatures are much more exceptional than they seem.

A homely and elusive creature

• Flies can travel 6 million times their body length in one flight, according to a recent study. Fruit flies can fly up to 15 kilometers in a single trip, 6 million times the length of your body, or the equivalent of more than 10,000 kilometers for the average human being. Compared to body length, this is more than many species of migratory birds can fly in a day.

• Under the influence of alcohol, flies too They are sexually similar to humans. What was found is that alcohol consumption did not affect the duration of copulation, but it reduced female choice and weakened the strength of mate preference, since females mated more quickly and with more males after consuming alcohol, potentially reducing the strength of sexual selection.

• The molecular motors that make wings flap repeatedly They have an energy efficiency rate of up to 40%. That is to say, by doing some calculations we can answer a curious question: How many flies would be necessary to pull a car? 200 million.

• Flies, depending on the species, They can live for very different times. But there is a myth that we must debunk: Mayflies don't live only 24 hours, dedicated exclusively to sex. Depending on the species, it can even live less than a day, or more. But that's just the final stage of life: mayflies spend most of their existence as aquatic nymphs, a period that can last anywhere from several months to four years.

In Xataka Science

This fossil pollen found in a fly's stomach is 47 million years old

• There is a very special type of fly in scientific studies. The fruit fly, Drosophila melanogaster, is a small insect about 3 millimeters long that grows on ripe fruit. Every week there is news of new scientific contributions that start from studying this small organism. It is small in size, with a life cycle of about two weeks, affordable maintenance and produces very numerous offspring. Numerous mutations also arise in its genes and its complete genome has already been sequenced.

• It consists of 3 pairs of legs that act as limbs that have adhesive pads that allow them to walk on smooth surfaces such as glass, even upside down.

• A great reaction speed. Flies are able to process what they see and react to it incredibly quickly, to put it in perspective: our brain processes around 60 images per second, while a fly can process up to 250 per second.

In Xataka Science

21 million images to track a fly's brain at the nanoscale

• These insects have been revered by different cultures over the centuries, with the Egyptian culture being one of those that paid the most tribute to flies. In fact, flies were seen by the pharaohs as synonymous with bravery and resistance to the enemy.

• He tries things through his paws. Flies have taste pupils in the last sections of their legs, so they can taste the taste of anything just by landing, from animal feces to your food.

• The head is small compared to the abdomen, and there are large, red eyes composed of thousands of individually light-sensitive facets (ommatidia) that they constantly clean by rubbing their legs, arranged in circles and that are connected directly to the brain.

In Xataka Science

The consequences of throwing an animal into a well (depending on size)

• The house fly practically vomits digestive juices on solid food, these juices are capable of dissolving your plate into small parts allowing you to now use your mouth to take food, a process called "proboscis." This can be perfectly seen in a terrifying scene from the movie The Fly.

• A single fruit fly can lay 500 eggs in its lifetime, and the life cycle from egg to adulthood only lasts about a week.

• Since house flies usually feed on feces, garbage and decaying animals and lay eggs there and in other disgusting places, the common house fly is believed to transmit at least 65 diseases to people, including diarrhea, dysentery or cholera.

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12 extraordinary curiosities about flies, one of the most repudiated animals

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Sergio Parra

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In Shark Bay, Western Australia, male bottlenose dolphins (Tursiops aduncus) form a complex hierarchy of social alliances. These alliances show a complexity like almost no other in the animal kingdom, almost comparable to that of humans.

Thus, at the first level, pairs or trios of unrelated males cooperate to raise individual females. Several first-order alliances cooperate in teams (second-order alliances) in searching for and defending females, and several teams also work together (third-order alliances).

Complex social hierarchy

However, It is unknown how dolphins classify these nested alliance relationships.. So in a new study published in Nature, 30 years of behavioral data combined with 40 contemporary sound playback experiments were used for 14 allied males, recording responses with drone-mounted videos.

It was thus shown that males form a first-person social concept of cooperative team membership at the second-order alliance level, regardless of the history of the first-order alliance and the strength of the current relationship at the three levels of alliance. alliance. Such associative concepts develop through experience.

This behavior can help reduce tension between males in a situation that requires them to cooperate successfully. This synchronized and coordinated behavior between allied males may therefore promote cooperative behavior and regulate stress, as has been shown to happen in humans.

These results provide evidence that cooperation-based concepts are not unique to humans., and occur in other animal societies with extensive cooperation between non-kin or nepotistic networks.

It is not the first evidence of the social complexity of these dolphins: Unrelated bottlenose dolphins have been observed teaching yourself a new way to use a tool, a behavior that until now had only been discovered in humans and other great apes. In a practice called "shelling."

Shark Bay, a World Heritage-listed area of Western Australia, is home to an iconic population of Indo-Pacific bottlenose dolphins. Only in this place have these cetaceans been observed using marine sponges, probably to protect their snout while they search for prey in the sand on the ground.

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The social complexity of Shark Bay dolphins is much more human-like than we had imagined

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Xataka Science

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Sergio Parra

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A toaster-sized experimental instrument aboard the rover called MOXIE (Mars Oxygen In-Situ Resource Utilization Experiment) has made NASA's Perseverance rover convert carbon dioxide from Mars into oxygen.

The test took place on April 20, the sixtieth Martian day, or sol, since the mission landed on February 18 in Jezero Crater.

MOXIE

In this first operation, MOXIE's oxygen production was about 5 grams, equivalent to approximately 10 minutes of breathable oxygen for an astronaut.

In Xataka Science

First temperature map of the red planet, unprecedented since NASA's Viking spacecraft

The atmosphere of Mars is 96% of carbon dioxide. MOXIE works by separating oxygen atoms from carbon dioxide molecules, which are made up of one carbon atom and two oxygen atoms. A waste product, carbon monoxide, is emitted into the Martian atmosphere. The conversion process requires high levels of heat to reach a temperature of approximately 800 degrees Celsius.

Transporting 25 tons of oxygen from Earth to Mars would be an arduous task. Transporting a one-ton oxygen converter, a larger, more powerful descendant of MOXIE that could produce those 25 tons, would be much more economical and practical. Jim Reuter, associate administrator of the Space Technology Mission Directorate (STMD):

In Xataka Science

We can now see the first high-definition images of China's Tianwen 1 mission

This is a critical first step in converting carbon dioxide to oxygen on Mars. MOXIE has more work to do, but the results of this technology demonstration are promising as we move toward our goal of one day seeing humans on Mars. Oxygen is not just what we breathe. Rocket propellant relies on oxygen, and future explorers will rely on propellant production on Mars to make the trip home.

MOXIE is expected to extract oxygen at least nine times more in the course of a Martian Year (almost two years on Earth).

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NASA's Perseverance rover has achieved the first of converting carbon dioxide from Mars into oxygen

was originally published in

Xataka Science

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Sergio Parra

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Even taking into account all the fat they accumulate to carry out their impressive migration, striped warblers (Setophaga striata) They have a mass of just 17 grams.

The equivalent of fifty aspirin tablets that makes a stopover of 2,770 kilometers across the open sea.

The journey

The Striated Warbler heads south in the fall from northwestern North America and travels to the Caribbean, and even to Colombia and Venezuela. For a long time, it was unknown how much time he spent flying over the ocean.

In Xataka Science

This is the longest bird migration ever recorded

Now, however, we already have the data in this regard, as explained David Barrie in his book The most incredible trips:

With the help of extraordinarily small tracking devices, scientists have managed to demonstrate that they can fly endlessly from Long Island to the island of Hispaniola or Puerto Rico, a distance of 2,770 kilometers across the open sea.

So these birds can complete non-stop flights of between 2,270 and 2,770 kilometers in just two or three days. Therefore, before starting the trip, it doubles its body mass by storing lipids and proteins, and it can do so in just one week. Later, The moment it begins to fly, a process of atrophy of its digestive system begins..

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A bird weighing only 17 grams that travels 2,770 kilometers across the open sea: the striped warbler

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Sergio Parra

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In a document sent to the Public Health Commission to be debated and approved this Tuesday in an extraordinary meeting, the Spanish Ministry of Health now proposed to delay the second dose of Pfizer and Moderna prophylaxis.

Although it had been stated that such a delay would not take place, in order to increase the rate of immunizations now it could be postponed this second dose specifically between 6 and 8 weeks among people under 80 years of age. Finally, however, this new strategy will not be adopted.

Other countries that do

This practice, which does not have the approval of the EMA (the data sheet Pfizer does not contemplate a delay in the immunization schedule), however was adopted by Israel and the United Kingdom at the beginning of the year. Although the strategy was viewed with a lot of skepticism at the time, it seems that finally has had good results.

In Xataka Science

Although herd immunity is still missing, vaccinating risk groups already has extraordinarily beneficial effects

There are already several countries that are following this line. Ireland, for example, has extended Pfizer's second deadline from 21 to 28 days. Denmark, Germany, France and Italy They recommend an interval of 6 weeks for Pfizer and Moderna. Finland has placed all second doses at 12 weeks. The United Kingdom also extended the second doses of all vaccines to 12 weeks, and Canada, to four months.

In Xataka Science

Leaving middle seats empty on a plane could give passengers more protection against coronavirus

It should be noted that the EMA does not prohibit extending the administration of the second dose up to 42 days (the product information does not explicitly determine the upper limit between doses), what it suggests, for the moment, is that We are not sure if this new space between vaccines can guarantee the same effectiveness confirmed by clinical trials.

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The vaccination strategy in Spain is not altered: Health will not space out the second dose of Pfizer and Moderna

was originally published in

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Sergio Parra

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