News and Articles on Science and Technology

Are natural #fibres really better for the environment than microplastic fibres?
▻https://phys.org/news/2019-03-natural-fibres-environment-microplastic.html

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“However, whilst they may not be plastic, ’natural’ textile fibres are far from a solution to the textile industry’s contribution to plastic pollution. The production of cotton is incredibly water intensive, and the methods used to process natural fibres often introduce a myriad of harmful chemicals into waters used for bathing and drinking. Moreover, the processing of natural fibres is often carried out in dangerous, exploitative working conditions.”

Tom adds: “As our research shows, there is a high percentage of natural fibres in our water – and we don’t really understand what impact this might have on the environment. What do we really know about the alternatives we are using in our efforts to curb plastic pollution? Much more needs to be done, before we can confidently say which of the alternatives available to us are the best for our planet.”

#plastique #eau #environnement

Abel Prize for #maths awarded to woman for first time
▻https://phys.org/news/2019-03-abel-prize-maths-awarded-woman.html

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Of the 607 Nobel prizes in physics, chemistry or medicine between 1901 and 2018, only 19 women were among the awardees, according to the Nobel Prize website. Marie Curie won twice, once for physics and another time for chemistry.

Only one woman has won the other major international mathematics prize—the Fields Medal—Maryam Mirzakhani of Iran in 2014. She died in 2017.

#physique #femmes

A mathematical approach for understanding intra-plant communication
▻https://phys.org/news/2019-01-mathematical-approach-intra-plant.html

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A team of researchers at the Gran Sasso Science Institute (GSSI) and Istituto Italiano di Technologia (IIT) have devised a mathematical approach for understanding intra-plant communication. In their paper, pre-published on bioRxiv, they propose a fully coupled system of non-linear, non-autonomous discontinuous and ordinary differential equations that can accurately describe the adapting behavior and growth of a single plant, by analyzing the main stimuli affecting plant behavior.

Recent studies have found that rather than being passive organisms, plants can actually exhibit complex behaviors in response to environmental stimuli, for instance, adapting their resource allocation, foraging strategies, and growth rates according to their surrounding environment. How plants process and manage this network of stimuli, however, is a complex biological question that remains unanswered.

Researchers have proposed several mathematical models to achieve a better understanding of plant behavior. Nonetheless, none of these models can effectively and clearly portray the complexity of the stimulus-signal-behavior chain in the context of a plant’s internal communication network.

The team of researchers at GSSI and IIT who carried out the recent study had previously investigated the mechanisms behind intra-plant communication, with the aim to identify and exploit basic biological principles for the analysis of plant root behavior. Their previous work analyzed robotic roots in a simulated environment, translating a set of biological rules into algorithmic solutions.

Even though each root acted independently from the others, the researchers observed the emergence of some self-organizing behavior, aimed at optimizing the internal equilibrium of nutrients at the whole-plant level. While this past study yielded interesting results, it merely considered a small part of the complexity of intra-plant communication, completely disregarding the analysis of above-ground organs, as well as photosynthesis-related processes.
“In this paper, we do not aspire to gain a complete description of the plant complexity, yet we want to identify the main cues influencing the growth of a plant with the aim of investigating the processes playing a role in the intra-communication for plant growth decisions,” the researchers wrote in their recent paper. “We propose and explain here a system of ordinary differential equations (ODEs) that, differently from state of the art models, take into account the entire sequence of processes from nutrients uptake, photosynthesis and energy consumption and redistribution.”

Chinese rover powers up devices in pioneering moon mission
▻https://phys.org/news/2019-01-chinese-rover-powers-devices-moon.html

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All systems are go as a Chinese spacecraft and rover power up their observation equipment after making a first-ever landing on the far side of the moon, the Chinese National Space Administration said.

The #Jade_Rabbit_2 rover has succeeded in establishing a digital transmission link with a relay satellite that sends data back to the Beijing control center, the space agency said in a posting late Friday on its website.

The rover’s radar and panoramic camera have been activated and are working normally, it said. A photo released by the agency showed the rover stopped at a point not far from where the Chang’e 4 spacecraft touched down Thursday.

Chang’e 4, named after a Chinese moon goddess, is the first craft to make a soft landing on the moon’s far side, which faces away from Earth. Previous landings, including one by China’s Chang’e 3 in 2013, have been on the near side.

Scientists find massive reserves of mercury hidden in permafrost
▻https://phys.org/news/2018-02-scientists-massive-reserves-mercury-hidden.html

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Researchers have discovered permafrost in the northern hemisphere stores massive amounts of natural mercury, a finding with significant implications for human health and ecosystems worldwide.

In a new study, scientists measured mercury concentrations in permafrost cores from Alaska and estimated how much mercury has been trapped in permafrost north of the equator since the last Ice Age.

The study reveals northern permafrost soils are the largest reservoir of mercury on the planet, storing nearly twice as much mercury as all other soils, the ocean and the atmosphere combined.

The new study was published today in Geophysical Research Letters, a journal of the American Geophysical Union.

#arctique #pollution #mercure

Life in deep Earth totals 15 to 23 billion tons of carbon—hundreds of times more than humans
▻https://phys.org/news/2018-12-life-deep-earth-totals-billion.html

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Barely living “zombie” bacteria and other forms of life constitute an immense amount of carbon deep within Earth’s subsurface—245 to 385 times greater than the carbon mass of all humans on the surface, according to scientists nearing the end of a 10-year international collaboration to reveal Earth’s innermost secrets.

Les entrailles de la #Terre grouillent de #vie «intraterrestre» | TVA Nouvelles
▻https://www.tvanouvelles.ca/2018/12/10/les-entrailles-de-la-terre-grouillent-de-vie-intraterrestre

[certaines] bactéries [...] fascinent les biologistes, car elles fonctionnent dans un système qui n’a rien à voir avec la surface où toute la chaîne alimentaire dépend de la #photosynthèse, qui fait pousser les plantes et permet à un ensemble d’organismes de se nourrir.

« Leur source d’énergie n’est pas le Soleil et la photosynthèse », dit à l’AFP Bénédicte Menez, responsable de l’équipe géomicrobiologie à l’Institut de Physique du Globe de Paris. « Ici ce qui fait démarrer les communautés, c’est la #chimiosynthèse, ils tirent leur énergie des roches, quand des roches s’altèrent ».

Dodging antibiotic resistance by curbing bacterial evolution
▻https://phys.org/news/2018-11-dodging-antibiotic-resistance-curbing-bacterial.html

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Combining antibiotics with an anti-evolution drug that reduces the rate of mutations in the pathogen might be one strategy against the development of antimicrobial resistance. Credit: Merrikh Lab/UW Medicine

#antibiotiques #antibiorésistance

Half of the world’s annual precipitation falls in just 12 days, new study finds
▻https://phys.org/news/2018-11-world-annual-precipitation-falls-days.html

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The findings, which suggest that flooding and the damage associated with it could also increase, have implications for water managers, urban planners, and emergency responders. The research results are also a concern for #agriculture, which is more productive when rainfall is spread more evenly over the growing season.

The research was supported by the U.S. Department of Energy and the National Science Foundation, which is NCAR’s sponsor.

#eau #climat #urbanisme

Rainforest destruction from gold mining hits all-time high in Peru
▻https://phys.org/news/2018-11-rainforest-destruction-gold-all-time-high.html

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That’s an area larger than San Francisco and 30 percent more than previously reported.

“The scale of the deforestation is really shocking,” said Luis Fernandez, executive director of CINCIA and research associate professor in the department of biology.

▻https://www.youtube.com/watch?v=uTUhUZ49v3g

Antarctic’s future in doubt after plan for world’s biggest marine reserve is blocked | World news | The Guardian
▻https://www.theguardian.com/world/2018/nov/02/plan-create-worlds-biggest-nature-reserve-antarctic-rejected

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A plan to turn a huge tract of pristine Antarctic ocean into the world’s biggest sanctuary has been rejected, throwing the future of one of the Earth’s most important ecosystems into doubt.

Environmental groups said Russia, China and Norway had played a part in blocking the proposal, with the other 22 members of the Commission for the Conservation of Antarctic Marine Living Resources, the organisation set up to protect Antarctic waters, backing the proposal.

The 1.8m sq km reserve – five times the size of Germany – would have banned all fishing in a vast area of the Weddell Sea and parts of the Antarctic peninsula, safeguarding species including penguins, killer whales, leopard seals and blue whales.

Experts said it would also have played a key role in tackling climate change, as the seas around the Antarctic soak up huge amounts of carbon dioxide from the atmosphere. But following days of talks in Hobart in Tasmania, the CCAMLR rejected the plan, which needed unanimous agreement to pass.

Scientists find corals in deeper waters under stress too
▻https://phys.org/news/2018-08-scientists-corals-deeper-stress.html

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Corals at this depth are thought of by some in the science community as being safer from ocean warming than their shallow-water counterparts. But the Scripps Oceanography team found that even in the deep, corals are episodically exposed to thermal stress at intervals different than those corals near the surface.

#climat

Les secrets de l’#évolution vus d’un papillon
▻https://www.futura-sciences.com/sante/actualites/genetique-secrets-evolution-vus-papillon-29565

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2011,

La fameuse phalène du bouleau, #papillon dont la rapide et spectaculaire évolution est prise en exemple dans tous les livres de #génétique, vient de révéler certains de ses secrets. Son changement de couleur serait probablement dû à un seul gène, porté par une région particulièrement mutagène.

Study confirms truth behind ’Darwin’s moth’
▻https://phys.org/news/2018-08-truth-darwin-moth.html

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Now scientists at the University of Exeter have shown that, to the vision of birds, pale moths are indeed more camouflaged against lichen-covered trees than dark moths—making pale moths less likely to be eaten by birds in unpolluted woodland and giving them an evolutionary advantage.

[...]

"Using digital image analysis to simulate bird vision and field experiments in British woodland, we compared how easily birds can see pale and darker moths, and ultimately determine their predation risk.

Un Prix : Kurdish refugee wins ’Nobel of #mathematics' #Fields_medal - une VF... - Une seule femme depuis le début de ce Prix...
▻https://phys.org/news/2018-08-british-iranian-kurd-fields-math.html
▻https://lemde.fr/2Ay3kOi
▻https://fr.wikipedia.org/wiki/Maryam_Mirzakhani

Via #Adrastia

Le réchauffement climatique pourrait être deux fois plus important que prévu par les modèles climatiques
"« Les observations des périodes de réchauffement passées suggèrent qu’un certain nombre de mécanismes amplificateurs, mal représentés dans les modèles climatiques, augmentent le réchauffement à long terme au-delà des projections du modèle climatique », explique le professeur Hubertus Fischer de l’Université de Berne.

"Cela suggère que le budget carbone pour éviter 2 ° C du réchauffement climatique pourrait être beaucoup plus faible que prévu, laissant très peu de marge d’erreur pour atteindre les objectifs de Paris."

Pour obtenir leurs résultats, les chercheurs ont examiné trois des périodes chaudes les mieux documentées, le maximum thermique de l’Holocène (5000-9000 ans), le dernier interglaciaire (129.000-116.000 ans) et la période chaude du milieu du Pliocène (3.3- Il y a 3 millions d’années).

Le réchauffement des deux premières périodes a été causé par des changements prévisibles de l’orbite terrestre, tandis que l’événement du milieu du Pliocène était le résultat de concentrations atmosphériques de dioxyde de carbone de 350 à 450 ppm, ce qui est sensiblement le même qu’aujourd’hui."

▻https://phys.org/news/2018-07-global-climate.html

#climat #collapsologie

Earth’s intact forests vanishing at accelerating pace: scientists (Update)
▻https://phys.org/news/2018-06-loss-earth-intact-forests-scientists.html

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Earth’s intact forests shrank by an area larger than Austria every year from 2014 to 2016 at a 20 percent faster rate than during the previous decade, scientists said Wednesday as the UN unveiled an initiative to harness the “untapped potential” of the land sector to fight climate change.

Despite a decades-long effort to halt deforestation, nearly 10 percent of undisturbed forests have been fragmented, degraded or simply chopped down since 2000, according to the analysis of satellite imagery.

Average daily loss over the first 17 years of this century was more than 200 square kilometres (75 square miles).

“Degradation of intact forest represents a global tragedy, as we are systematically destroying a crucial foundation of climate stability,” said Frances Seymour, a senior distinguished fellow at the World Resources Institute (WRI), and a contributor to the research, presented this week at a conference in Oxford.

“Forests are the only safe, natural, proven and affordable infrastructure we have for capturing and storing carbon.”

#forêt #déforestation

UK, U.S. study Antarctic glacier, hoping to crack sea level risks | Agricultural Commodities | Reuters
▻https://af.reuters.com/article/commoditiesNews/idAFL8N1S72CG

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Britain and the United States launched a $25 million project on Monday to study the risks of a collapse of a giant glacier in Antarctica that is already shrinking and nudging up global sea levels.

The five-year research, involving 100 scientists, would be the two nations’ biggest joint scientific project in Antarctica since the 1940s. Ice is thawing from Greenland to Antarctica and man-made global warming is accelerating the trend.

The scientists would study the Thwaites Glacier, which is roughly the size of Florida or Britain, in West Antarctica, the UK Natural Environment Research Council and U.S. National Science Foundation said in a joint statement.

(image issue de
Study shows Thwaites Glacier’s ice loss may not progress as quickly as thought
▻https://phys.org/news/2017-06-thwaites-glacier-ice-loss-quickly.html

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New study shows seafloor #erosion now occurring like coastal land loss
▻https://phys.org/news/2018-04-seafloor-erosion-coastal-loss.html

@sinehebdo

Scientists have discovered that the seafloor from the Mississippi River Delta to the Gulf of Mexico is eroding like the land loss that is occurring on the Louisiana coast. During the 20th century, thousands of dams were built on Mississippi River tributaries stopping the flow of fine silt, clay and other sediment from reaching the delta and seafloor to offset erosion. Without this sediment, land —in the form of wetlands and the seafloor— is lost, which threatens offshore and inland infrastructure in the face of waves, hurricanes and surge, or flooding, from storms. Land loss also affects marine plants and animals as well as how #pollution is absorbed and broken down. In this new comprehensive study, scientists have mapped the retreat of the seafloor from the Mississippi River Delta into the Gulf of Mexico for the first time. This research was published recently in the journal Marine Geology.

[...]

“Given the similarities between the Mississippi River Delta and river systems worldwide, we expect other major delta systems are entering decline. This has implications for delta ecosystems and biological, geological and chemical processes worldwide,”

#sols #barrages #écosystèmes #fond_marin

Scientists engineer crops to conserve water, resist drought
▻https://phys.org/news/2018-03-scientists-crops-resist-drought.html

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#Agriculture already monopolizes 90 percent of global freshwater—yet production still needs to dramatically increase to feed and fuel this century’s growing population. For the first time, scientists have improved how a crop uses water by 25 percent without compromising yield by altering the expression of one gene that is found in all plants, as reported in Nature Communications.

Intensive agriculture influences U.S. regional summer climate, study finds
▻https://phys.org/news/2018-02-intensive-agriculture-regional-summer-climate.html

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Scientists agree that changes in land use such as deforestation, and not just greenhouse gas emissions, can play a significant role altering the world’s climate systems. Now, a new study by researchers at MIT and Dartmouth College reveals how another type of land use, intensive agriculture, can impact regional climate.

The researchers show that in the last half of the 20th century, the midwestern U.S. went through an intensification of agricultural practices that led to dramatic increases in production of corn and soybeans. And, over the same period in that region, summers were significantly cooler and had greater rainfall than during the previous half-century. This effect, with regional cooling in a time of overall global warming, may have masked part of the warming effect that would have occurred over that period, and the new finding could help to refine global climate models by incorporating such regional effects.

#climat #agroindustrie

Colonisation de l’Amérique : la route du Varech.

Une équipe d’anthropologues de plusieurs institutions aux États-Unis abandonnent le point de vue conventionnel selon lequel les peuples "Clovis" (#Clovis-first_model) ont traversé un pont terrestre sur l’actuel détroit de Béring ont été les premiers arrivés en Amérique. Des preuves plus récentes suggèrent que d’autres sont arrivés bien plus tôt, utilisant probablement des bateaux et faisant du cabotage.

Cela aurait été possible, notent les auteurs, à cause de ce qui a fini par être connu sous le nom de « varech » ; les forêts de varech poussant juste au large. Tout ce varech aurait fourni un riche habitat pour les créatures marines qu’auraient pu manger les voyageurs.

Les auteurs concluent en soulignant que trop peu de recherches ont été faites au large des côtes - les premiers voyageurs auraient résidé principalement sur des terres maintenant recouvertes par la mer en raison des niveaux océaniques mondiaux plus élevés.

Les auteurs concluent en soulignant que trop peu de recherches ont été faites au large des côtes - les premiers voyageurs auraient résidé principalement sur des terres maintenant recouvertes par la mer en raison des niveaux océaniques mondiaux plus élevés.

Cette réflexion rejoint celle d’Emmanuel Guy qui, lui aussi, pense que de nombreux abris, campements sont actuellement au large de nos côtes.
►https://clio-cr.clionautes.org/ce-que-l-art-prehistorique-dit-de-nos-origines.html

Read more at : ▻https://phys.org/news/2017-11-anthropologist-group-humans-americas-kelp.html

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#préhistoire #peuplement #clovis #14000-18000BP #Amérique