Down-ranking polarizing content lowers emotional temperature on social media – new research

Source: The Conversation – USA – By Tiziano Piccardi, Assistant Professor of Computer Science, Johns Hopkins University

Social media posts that stoke division don’t have to top your feed. Gama5/iStock via Getty Images

Reducing the visibility of polarizing content in social media feeds can measurably lower partisan animosity. To come up with this finding, my colleagues and I developed a method that let us alter the ranking of people’s feeds, previously something only the social media companies could do.

Reranking social media feeds to reduce exposure to posts expressing anti-democratic attitudes and partisan animosity affected people’s emotions and their views of people with opposing political views.

I’m a computer scientist who studies social computing, artificial intelligence and the web. Because only social media platforms can modify their algorithms, we developed and released an open-source web tool that allowed us to rerank the feeds of consenting participants on X, formerly Twitter, in real time.

Drawing on social science theory, we used a large language model to identify posts likely to polarize people, such as those advocating political violence or calling for the imprisonment of members of the opposing party. These posts were not removed; they were simply ranked lower, requiring users to scroll further to see them. This reduced the number of those posts users saw.

We ran this experiment for 10 days in the weeks before the 2024 U.S. presidential election. We found that reducing exposure to polarizing content measurably improved participants’ feelings toward people from the opposing party and reduced their negative emotions while scrolling their feed. Importantly, these effects were similar across political affiliations, suggesting that the intervention benefits users regardless of their political party.

This ‘60 Minutes’ segment covers how divisive social media posts get more traction than neutral posts.

Why it matters

A common misconception is that people must choose between two extremes: engagement-based algorithms or purely chronological feeds. In reality, there is a wide spectrum of intermediate approaches depending on what they are optimized to do.

Feed algorithms are typically optimized to capture your attention, and as a result, they have a significant impact on your attitudes, moods and perceptions of others. For this reason, there is an urgent need for frameworks that enable independent researchers to test new approaches under realistic conditions.

Our work offers a path forward, showing how researchers can study and prototype alternative algorithms at scale, and it demonstrates that, thanks to large language models, platforms finally have the technical means to detect polarizing content that can affect their users’ democratic attitudes.

What other research is being done in this field

Testing the impact of alternative feed algorithms on live platforms is difficult, and such studies have only recently increased in number.

For instance, a recent collaboration between academics and Meta found that changing the algorithmic feed to a chronological one was not sufficient to show an impact on polarization. A related effort, the Prosocial Ranking Challenge led by researchers at the University of California, Berkeley, explores ranking alternatives across multiple platforms to promote beneficial social outcomes.

At the same time, the progress in large language model development enables richer ways to model how people think, feel and interact with others. We are seeing growing interest in giving users more control, allowing people to decide what principles should guide what they see in their feeds – for example the Alexandria library of pluralistic values and the Bonsai feed reranking system. Social media platforms, including Bluesky and X, are heading this way, as well.

What’s next

This study represents our first step toward designing algorithms that are aware of their potential social impact. Many questions remain open.

We plan to investigate the long-term effects of these interventions and test new ranking objectives to address other risks to online well-being, such as mental health and life satisfaction. Future work will explore how to balance multiple goals, such as cultural context, personal values and user control, to create online spaces that better support healthy social and civic interaction.

The Research Brief is a short take on interesting academic work.

The Conversation

This research was partially supported by a Hoffman-Yee grant from the Stanford Institute for Human-Centered Artificial Intelligence.

ref. Down-ranking polarizing content lowers emotional temperature on social media – new research – https://theconversation.com/down-ranking-polarizing-content-lowers-emotional-temperature-on-social-media-new-research-271071

L’« effet Lazare », ou quand certains êtres vivants ressurgissent après des millions d’années

Source: The Conversation – France (in French) – By Violaine Nicolas Colin, Maitre de conférence en systématique et phylogéographie, Muséum national d’histoire naturelle (MNHN)

Les lézards iguanidés ( ici, _G. longicaudatus_) étaient très répandus et diversifiés en Europe durant l’Éocène (entre 56 millions et 33,9 millions d’années). On les pensait totalement disparus du continent après la transition Éocène-Oligocène. Jusqu’à la découverte, en 2012, de spécimens du genre _Geiseltaliellus_ dans le sud de la France. Chris Woodrich, CC BY

Nommé d’après la figure biblique revenue d’entre les morts, l’« effet Lazare » désigne un phénomène bien plus fréquent qu’on ne le pense : la réapparition de certains groupes d’organismes que l’on croyait éteints.


Tout le monde connaît Lazare, ce personnage du Nouveau Testament que Jésus aurait ramené à la vie. C’est de cette image symbolique qu’est né le terme d’« effet Lazare », utilisé aujourd’hui dans différents domaines de la biologie.

En paléontologie et en phylogénie (l’étude des relations évolutives entre les organismes), il désigne un phénomène fascinant : celui de groupes d’organismes – espèces, genres ou familles – qui semblent avoir disparu pendant des millions d’années si l’on se fie à l’ensemble des fossiles découverts à ce jour, avant de réapparaître comme par miracle.

Le concept a été introduit dans les années 1980 par les scientifiques états-uniens Karl Flessa et David Jablonski, puis affiné par la suite. Toutefois, les scientifiques ne sont pas toujours d’accord sur la manière de le définir : certains, comme Jablonski, y voient une simple absence temporaire dans les archives fossiles pendant un intervalle de temps donné, d’autres le réservent aux retours spectaculaires après les grandes crises d’extinction massive.

Pourquoi ces « résurrections » apparentes ?

L’effet Lazare demeure de fait étroitement lié à la qualité du registre fossile, c’est-à-dire à l’ensemble des fossiles découverts à ce jour, qui n’offre qu’une image partielle du passé de la vie. La fossilisation est un processus rare et sélectif : certains organismes se fossilisent mieux (par exemple, ceux dotés de coquilles ou d’os) et certains milieux (comme les fonds marins) favorisent la conservation des restes biologiques. De plus, les roches peuvent être détruites, transformées ou tout simplement jamais explorées. Résultat : de larges pans de l’histoire du vivant nous échappent encore.

L’absence d’un taxon (unité de genre, de famille ou d’espèce) dans le registre fossile pendant des millions d’années peut donc avoir deux explications :

  • une cause « stratigraphique », autrement dit un trou dans les archives. Le taxon a bien survécu, mais nous n’en avons conservé aucune trace ;

  • une cause « biologique » signifiant qu’il s’agit d’un véritable événement évolutif.

Plusieurs scénarios peuvent alors expliquer cette disparition apparente :

→ Le taxon a pu trouver refuge dans des zones isolées, de petite taille ou mal explorées. Après une longue période d’isolement dans ces refuges, le taxon a ensuite envahi de nouveau son territoire originel et est réapparu dans le registre fossile.

→ Il a pu subsister à très faible densité, en dessous du seuil nécessaire pour laisser des traces fossiles. En dessous de ce seuil, la population reste viable, mais nous n’avons tout simplement aucune trace de son existence. Malheureusement, ce seuil varie selon les environnements et les taxons, et il est quasiment impossible à quantifier.

La distinction entre les alternatives stratigraphique et biologique est souvent difficile. L’intensité des fouilles, la qualité de l’identification des fossiles et le niveau taxonomique (espèce, genre, famille…) jouent tous un rôle crucial dans l’interprétation de ces cas. Il faut aussi noter que l’interprétation de l’effet Lazare est une procédure asymétrique, car l’alternative biologique n’est privilégiée que lorsque l’alternative stratigraphique ne peut être documentée. Par conséquent, les techniques analytiques évaluant l’exhaustivité des archives fossiles sont essentielles pour comprendre la signification des taxons Lazare.

Origines de l’effet Lazare mettant en évidence les alternatives stratigraphique et biologique qui soit empêchent la préservation, soit limitent le nombre de restes préservés encore non découverts en raison d’un échec d’échantillonnage. Adapté de Fara (2001).
Fourni par l’auteur

Quand la vie joue à cache-cache : quelques exemples

Une chose reste elle certaine, les exemples de taxons Lazare sont bien moins rares qu’on pourrait le penser.

Les lézards iguanidés, par exemple, étaient très répandus et diversifiés en Europe durant l’Éocène (de -56 millions à -33,9 millions d’années). On pensait qu’ils avaient totalement disparu du continent après la transition Éocène-Oligocène. Pourtant, la découverte, en 2012, de spécimens du genre Geiseltaliellus dans le sud de la France a montré qu’ils avaient survécu quelque temps en faible abondance avant de s’éteindre définitivement, probablement à la fin de l’Oligocène, il y a 23 millions d’années.

Autre cas remarquable : le gastéropode du genre Calyptraphorus. Longtemps considéré comme disparu à la fin de l’Éocène, il a refait surface au Pliocène (de -5,3 millions à -2,6 millions d’années) dans des gisements des Philippines (Asie du Sud-Est), prolongeant son existence fossile d’environ 30 millions d’années ! Cette longévité cachée suggère qu’il aurait survécu discrètement dans des zones refuges du Pacifique tropical.

La redécouverte d’espèces vivantes appartenant à des groupes que l’on pensait éteints constitue une expression rare et spectaculaire de l’effet Lazare. Parmi les exemples les plus emblématiques on peut par exemple citer, le cœlacanthe, véritable icône de l’effet Lazare. Ce poisson, que l’on croyait éteint depuis 66 millions d’années, a été redécouvert vivant en 1938 au large de l’Afrique du Sud (Afrique australe).

Un autre cas remarquable est celui de Laonastes, un petit rongeur découvert en 2005 au Laos, en Asie du Sud-Est, sur les étals d’un marché local de viande sauvage. Au départ, les chercheurs pensaient avoir affaire à une nouvelle famille de rongeurs, qu’ils ont appelée Laonastidæ.

Le kanyou (Laonastes aenigmamus) est un rongeur découvert au Laos dans la province de Khammouane. Décrit en 2005 il est le seul représentant vivant de la famille de Diatomyidæ ; famille que l’on pensait disparue depuis plus de 11 millions d’années
Le kanyou ou khan-you (Laonastes aenigmamus) est un rongeur découvert au Laos, dans la province de Khammouane. Décrit en 2005, il est le seul représentant vivant de la famille des Diatomyidæ ; famille que l’on pensait disparue depuis plus de 11 millions d’années.
Jean-Pierre Hugot, CC BY

Cette classification reposait sur des analyses génétiques basées sur un nombre limité de gènes et sur la comparaison de sa morphologie avec celle d’espèces actuelles. Mais un véritable bouleversement scientifique est survenu lorsque les scientifiques ont intégré des fossiles dans leurs analyses morphologiques. En comparant en détail le crâne, la mandibule, les dents et le squelette de Laonastes avec des rongeurs fossiles et actuels, ils ont découvert qu’il appartenait en réalité à la famille des Diatomyidæ, que l’on croyait éteinte depuis plus de 11 millions d’années.

Ces analyses ont également révélé que les plus proches parents actuels de cette famille sont les goundis Ctenodactylus gundi. Des études génétiques plus poussées sur les espèces actuelles ont ensuite confirmé ce lien de parenté entre Laonastes et les goundis, et révélé que ces deux lignées auraient divergé il y a environ 44 millions d’années. Laonastes représente donc un exemple frappant de taxon Lazare.

Pourquoi ces découvertes sont-elles si importantes ?

Les taxons Lazare sont ainsi bien plus que des curiosités de la nature. Ils offrent aux scientifiques des clés uniques pour comprendre l’évolution du vivant, la résilience des espèces face aux crises et surtout les limites du registre fossile.

En phylogénie, leur réapparition peut modifier notre compréhension des liens de parenté entre les espèces, des dates de divergence et d’extinction ou encore de la vitesse d’évolution morphologique.

En paléontologie, ils rappellent à quel point le registre fossile est biaisé et incomplet, et combien il faut être prudent avant de déclarer une espèce « disparue ».

Enfin, les taxons Lazare montrent que la vie ne disparaît pas toujours là où on le croit. Parfois, elle se retire simplement dans l’ombre pour ressurgir des millions d’années plus tard, comme un témoin silencieux de la longue histoire de l’évolution.

Parce que dans les usages de nomenclature biologique, seuls les noms de rangs générique et infra-générique (genre, espèce, sous-espèce) se composent en italique, tandis que les noms de familles et au-dessus (famille, sous-famille, ordre, etc.) se composent en romain. Ainsi, Laonastidæ a parfois été perçu comme un nom de genre par confusion et mis en italique à tort, alors que Diatomyidæ est un nom de famille correctement laissé en romain.

The Conversation

Violaine Nicolas Colin a reçu des financements de l’ANR.

ref. L’« effet Lazare », ou quand certains êtres vivants ressurgissent après des millions d’années – https://theconversation.com/l-effet-lazare-ou-quand-certains-etres-vivants-ressurgissent-apres-des-millions-dannees-269236

Le bonheur s’achète-t-il en solde ?

Source: The Conversation – France (in French) – By Mickaël Mangot, Docteur en économie, spécialiste d’économie comportementale et d’économie du bonheur, conférencier, chargé de cours, ESSEC

Les difficultés de la vie quotidienne peuvent modérer le bénéfice de la consommation sur notre bonheur. Pack-Shot/Shutterstock

Consommer nous rend-il plus heureux ? Les soldes nous rapprochent du bonheur ou, au contraire, nous en éloigne-t-il ? Selon l’économie du bonheur, toutes les consommations ne se valent pas…

Depuis le début des années 1970, l’économie du bonheur constitue un courant de recherche, au sein de la science économique, qui se propose de décrypter comment les comportements des individus influencent leur niveau de bonheur.

Si la relation entre revenus et bonheur a beaucoup occupé la discipline, de plus en plus de chercheurs s’intéressent désormais à la relation entre consommation et bonheur, sur un plan quantitatif – combien on consomme – comme qualitatif – ce que l’on consomme.

Est-on d’autant plus heureux que l’on consomme ? À l’instar de la relation entre revenus et bonheur, la réponse est clairement affirmative, que ce soit en Europe, aux États-Unis ou en Asie. Mais, comme pour le revenu, la consommation explique à elle seule très peu des différences de bonheur entre individus, entre 5 % et 15 %. Il existe beaucoup de personnes qui sont heureuses tout en consommant peu et, inversement, des individus très dépensiers qui sont insatisfaits de leur vie.

Impact éphémère

Cette absence de relation forte entre niveau de consommation et niveau de bonheur s’explique en grande partie par plusieurs mécanismes psychologiques.

Hormis quelques exceptions – chômage, handicap lourd, maladies chroniques ou dégénératives, etc., les humains s’adaptent aux chocs de vie, positifs ou négatifs.

La consommation, notamment de biens matériels, fait partie de ces événements qui ne laissent plus aucune de trace sur le bonheur à moyen long terme. Une fois l’achat effectué, nos consommations sont vite reléguées à l’arrière-plan de nos vies. Cette règle s’applique autant pour les petits achats – vêtements, déco ou high-tech – que pour les biens durables très onéreux comme la voiture ou le logement.

Les désirs se renouvellent et progressent constamment. Plus le niveau de vie augmente, plus les aspirations s’élèvent.

Cette montée en gamme (ou lifestyle inflation) s’applique à tout : logement, voiture, vêtements, restaurants, loisirs… À 20 ans on rêve d’un McDo et d’une chambre de bonne et à 60 ans d’un restaurant étoilé et d’une maison de maître. Dans nos armoires ou sur nos étagères, les consommations passées sont les vestiges visibles de désirs aujourd’hui dépassés.

Compétition sociale

S’ajoute aussi le mécanisme de la comparaison sociale : on fait l’expérience de son niveau de vie en partie cognitivement, en l’évaluant par rapport à celui des autres. Un niveau de vie élevé n’est pas gage de satisfaction s’il traduit un statut inférieur à celui de ses collègues, de ses voisins et de sa famille.

Ce n’est donc pas seulement notre propre consommation qui est importante pour le bonheur (positivement), mais également celle de notre entourage immédiat (négativement), du moins pour les consommations facilement observables – logement, voiture, vêtements, montres…

La satisfaction de la vie au sein d’un ménage augmente en fonction du rang de ce ménage en termes de consommation observable au sein de la même localité. D’ailleurs, lorsqu’un ménage gagne à la loterie, cela tend à augmenter les consommations observables des ménages dans ses alentours.




À lire aussi :
Soldes : les commerçants sont-ils d’honnêtes manipulateurs ?


L’observation de biens de luxe chez les autres peut être particulièrement nocive pour le bonheur. Une étude a obtenu que plus la proportion de Porsche et de Ferrari est élevée dans une ville ou une région, et plus le niveau de bonheur moyen y était faible.

Privilégier les expériences

De nombreux travaux ont cherché à distinguer différents types de consommation selon leur intensité et selon la durabilité de leur impact sur le bonheur. Ils ont fait émerger une liste de consommations plus propices au bonheur :

Ces consommations ont la particularité de renforcer la connexion aux autres, d’améliorer l’image sociale ou l’image de soi, ou de contribuer à forger une identité.

Il est à noter que la liste n’est pas exactement la même pour tout le monde. Elle est modérée par les valeurs, la personnalité et les difficultés propres à la personne. Les biens matériels influencent plus le bonheur des personnes ayant des revenus modestes ou des valeurs matérialistes. Les valeurs matérialistes expliquent que la possession d’une voiture et sa valeur marchande sont particulièrement impactantes pour le bonheur des… boomers.

Plus la consommation est alignée avec la personnalité, et plus elle a généralement d’effet. Par exemple, les extravertis bénéficient plus que les introvertis des consommations sociales comme les sorties dans les bars et restaurants, et inversement pour les achats de livres.

Pallier les difficultés

Les difficultés du quotidien modèrent l’effet de la consommation sur le bonheur. La voiture est particulièrement importante pour le bonheur chez les personnes qui ont des problèmes de mobilité du fait d’une santé défaillante ou de l’absence d’alternatives. De même, le recours à des services pour gagner du temps est particulièrement efficace pour doper le bonheur des personnes qui en manquent (comme les parents en activité).

Ces dernières observations sont à relier à un autre mécanisme psychologique fondamental : le biais de négativité. Les émotions négatives affectent plus fortement et plus durablement l’évaluation de la vie que les émotions positives. On s’adapte en général moins rapidement aux chocs de vie négatifs qu’aux chocs positifs.

Les domaines de la vie pour lesquels on est insatisfait influencent plus l’évaluation générale de la vie que les domaines apportant satisfaction. Les consommations ont généralement plus d’effet sur le bonheur quand elles permettent de corriger un manque, plutôt que lorsqu’elles ajoutent du positif.

Plaisir de la transaction

Ces découvertes sont, pour certaines, plutôt intuitives. Néanmoins, les consommateurs peinent à en tirer les leçons pratiques du fait d’erreurs systématiques au moment des décisions. Par exemple, ils tendent à sous-estimer la puissance de l’adaptation aux évènements de la vie, notamment positifs, tout comme ils sous-estiment leurs changements de goûts et de priorités dans le temps.

Lors d’un achat, la quête du bonheur entre souvent en conflit avec la recherche d’une rationalité économique. La satisfaction attendue de la consommation est mise en balance avec le plaisir de la transaction, comme l’a montré le Prix Nobel d’économie Richard Thaler. En période de promotions, on se laisse aller à acheter des produits dont on n’a ni besoin ni réellement envie uniquement pour faire une bonne affaire. Le plaisir de la transaction est éphémère ; après coup on oublie vite avec quel niveau de remise l’achat a été réalisé.

Finalement, essayons de renverser la question : être vraiment heureux changerait-il notre façon de consommer ? Quelques études pionnières suggèrent que les personnes heureuses consomment différemment des autres : elles consomment moins (et épargnent plus) tout en ayant une consommation davantage orientée vers les sorties que vers les biens matériels. Ces études ne disent pas, en revanche, si ces personnes déjà très heureuses vont jusqu’à ignorer le Black Friday…

The Conversation

Mickaël Mangot ne travaille pas, ne conseille pas, ne possède pas de parts, ne reçoit pas de fonds d’une organisation qui pourrait tirer profit de cet article, et n’a déclaré aucune autre affiliation que son organisme de recherche.

ref. Le bonheur s’achète-t-il en solde ? – https://theconversation.com/le-bonheur-sachete-t-il-en-solde-270576

Sumatra’s flood crisis: How deforestation turned a cyclonic storm into a likely recurring tragedy

Source: The Conversation – Indonesia – By Dian Fiantis, Professor of Soil Science, Universitas Andalas

Cyclone Senyar hit South and Southeast Asian countries in late November. In Indonesia, the island of Sumatra, especially its northern parts, took the worst hit.

The storm set off flash floods and landslides that tore through towns, killed hundreds of people, and pushed thousands of families out of their homes. Many houses were submerged to their rooftops or swept away entirely, while rivers turned into sudden, violent torrents.

But this wasn’t just a natural disaster brought on by intense rain. Weather was only part of the story. The real damage occured when extreme rainfall collided with an already weakened ecosystem.

The result was a deadly catastrophe.

When forests are cleared and the land is degraded, the ecosystem loses its natural ability to act as a “sponge.” Rainwater that once slowly seeped into the forest floor now rushes over the land, turning into torrential runoff that crashes into people’s homes.

This is why the recent floods in Sumatra must be understood not only as a hydrometeorological phenomenon, but as a sign of ecosystem collapse: the soil–forest–water cycle is degrading, exacerbated by decades of deforestation and land-use change.

Healthy soil: A silent water absorber

Healthy soil works like a sponge. It is rich in organic matter and full of pores and channels created by roots and soil organisms. Well-maintained soil can absorb remarkably large volumes of water.

A forest is not only a collection of trees. It is a hydrological system whose functions extend from underground to the atmosphere. Plant roots create pathways for water to seep into the soil, the canopy slows the fall of rain, and leaf litter protects the surface from erosion. Trees absorb water from the soil and release it through transpiration, helping regulate humidity and rainfall patterns.

When forests are cleared for plantations, mining, or agricultural expansion, the soil’s capacity to absorb water collapses. The roots that once bound the soil decay. The soil loses its protection. Leaf litter disappears. Organic matter declines, the soil becomes compacted, eroded, and damaged.

As a result, the landscape loses its ability to absorb water, runoff increases, and slopes in hilly and mountainous regions become unstable. Meanwhile, rivers receive large amounts of water in a short time. When they cannot contain it, they overflow, triggering deadly floods.




Baca juga:
Death and devastation: why a rare equatorial cyclone and other storms have hit southern Asia so hard


The case of Sumatra

In North Sumatra, the Batang Toru, a major river in the Tapanuli Selatan highlands, flows through one of the most biodiverse mountain ranges.

Its watershed provides water for irrigation, household use, fisheries, and micro-hydropower.

The surrounding tropical rainforest is the last primary forest block in this region, serving as home for a huge biodoversity and acting as a natural buffer against floods and landslides.

But this resilience is rapidly disappearing. The northern zone of Batang Toru, at 300–400 metres elevation, has been opened up for mining since 2010. Forest clearing for oil palm plantations continued until 2024.

Our latest satellite analysis shows that approximately 1,550 hectares of the forests in the area have lost their vegetation cover, leaving bare soil highly susceptible to erosion in the Batang Toru watershed.

Degraded slopes like these can no longer absorb rainfall or stabilise the watershed. Communities downstream become increasingly vulnerable when extreme storms hit.

In West Sumatra, a week earlier, relentless rainfall soaked Padang City. Rainfall intensity rose sharply: daily totals increased from 37 mm on 19 November to 145 mm on 27 November 2025, with total accumulation exceeding 770 mm. The soil finally gave way, unable to hold any more water in its pore network.

An estimated 152 hectares of forest have been lost in the upstream areas of the Batang Kuranji and Batang Aie Dingin rivers in Padang City. As a result, the entire water cycle has been disrupted. Groundwater recharge declined, surface runoff increased, and rivers turned “ferocious,” with surging discharge volumes that triggered flooding.

When rain falls, the water is clear. But during floods, it turns brownish-yellow or even black — a sign that eroded soil has been carried away by the flow.

Four days after the flash floods, the Batang Kuranji (19.68 km) and Batang Aie Dingin (14.27 km) rivers in Padang remained brownish-yellow, flowing rapidly towards Padang Beach.

Communities suffer the consequences, while coastal ecosystems become increasingly choked by sediment.

The four rivers in Padang originate in the Bukit Barisan Mountains, where their exposed soil surfaces easily wash away during heavy rain.

Ecosystem-based disaster adaptation

We often see deforestation and soil degradation as local issues. But the scale of the impacts shows that these problems carry national consequences.

As extreme rainfall becomes more frequent, every damaged watershed becomes a risk multiplier.

In areas with healthy soils and intact forests, storms can still cause damage, but the ecosystem absorbs part of the impact. In critically degraded areas, the same storm can escalate into a major disaster.

Taking the lesson from Sumatra, this shows that a climate resilience strategy cannot rely solely on levees, dams, or emergency responses. We must rebuild the ecological infrastructure that regulates water flow.

Maintaining the soil–forest–water relationship is essential for our safety — now and in the future.

Thus, we must protect remaining forests, especially headwater catchments and peatlands; restore degraded soils by increasing organic matter, expanding agroforestry, and promoting sustainable farming practices; and include soil-health and land-cover indicators in flood-risk planning.

Ecosystem-based adaptation, from reforestation to planting vegetation along riverbanks, must go hand in hand with engineered solutions.

If we only react to disasters without restoring the ecological buffers that prevent them, future floods will be even bigger and more deadly.

Extreme weather will always come. But we can reduce the impacts by restoring forests and improving the condition of the soils beneath our feet so that the next storm does not have to become the next tragedy.

The Conversation

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ref. Sumatra’s flood crisis: How deforestation turned a cyclonic storm into a likely recurring tragedy – https://theconversation.com/sumatras-flood-crisis-how-deforestation-turned-a-cyclonic-storm-into-a-likely-recurring-tragedy-271302

Becoming human in southern Africa: what ancient hunter-gatherer genomes reveal

Source: The Conversation – Africa (2) – By Marlize Lombard, Professor with Research Focus in Stone Age Archaeology, Palaeo-Research Institute, University of Johannesburg

New genetic research is shedding light on some of the earliest chapters of our human history. In one of the largest studies of its kind, scientists analysed DNA from 28 individuals who lived in southern Africa between 10,200 and a few hundred years ago. The study provides more evidence that hunter-gatherers from southern Africa were some of the earliest modern human groups, with a genetic ancestry tracing back to about 300,000 years ago. Marlize Lombard, an archaeologist whose research focuses on the development of the human mind, breaks down the key findings.

Why did you study the DNA of ancient hunter-gatherers in southern Africa?

According to the genetic, palaeo-anthropological and archaeological evidence, modern humans – Homo sapiens – originated in Africa hundreds of thousands of years ago and then spread around the world. But the evolutionary process of exactly how, where and when this happened is debated.

Africa has the greatest human genetic diversity and the hunter-gatherers of southern Africa represent some of the oldest known genetic lineages. They can therefore reveal more about where and when we originated as a species.

After thousands of years of migration, modern African populations have a mixed genetic heritage. So their genomes are not very helpful for understanding our deep evolutionary history. For that, we need to look at genetic variation among individuals living before large-scale population movements on the continent.

In southern Africa, it means going back to before about 1,400-2,000 years ago. It also means that such rare ancient hunter-gatherer DNA can provide valuable information, not available in the DNA of living people.

What we specifically wanted to learn from the ancient southern African DNA was to which extent the biological and behavioural patterns we observe in the fossil and archaeological records were continuous and particular to the region.

For example, at a South African fossil-bearing site called Florisbad, we have a human skull dating to about 260,000 years ago that shows a possible transition from Homo heidelbergensis into Homo sapiens. And from about 100,000 years ago there was a rapid increase in technological innovations such as paint-making, glue-making and long-range weapon use.

We sequenced the DNA of 28 ancient individuals from what is now South Africa, all dating to the Holocene epoch that started about 11,700 years ago. DNA sequencing “reads” the order of the chemical base-pairs that make up an individual’s DNA. This helps us to reconstruct a person’s genome, or their complete set of genetic information. Among other things, it can tell us something about the individual’s biological and behavioural characteristics.

Eight of the individuals used to live near the coast at Matjes River, in today’s Western Cape province. Several others lived at inland sites across South Africa. We dated their remains with radiocarbon dating, finding that the oldest died about 10,200 years ago at Matjes River and the most recent died just 280 years ago in the Free State. (All DNA from archaeological contexts is scientifically known as ancient DNA.)

What did the DNA reveal?

Our study shows that the genetic makeup of the southern African hunter-gatherer population didn’t change much for 9,000 years across the whole of South Africa, not only in the southern Cape, even though their technologies and lifeways may have changed or differed during this time.

All ancient southern Africans dated to more than 1,400 years ago had some unique Homo sapiens genetic variations. The ancient DNA had genes associated with UV-light protection, skin diseases, and skin pigmentation. These could have been essential to life on southern Africa’s grasslands and fynbos. Among the genetic variants that were common to ancient and modern humans were genes related to kidney function (potentially connected to improved water-retention) and immune-system related genes.

About 40% of the ancient southern African genes are associated with neurons, brain growth and the way that human brains process information today. Some of these gene variants may have been involved in the evolution of how humans pay attention today. Attention is a cognitive or mental trait that seems to have evolved differently in African Homo sapiens compared to the now extinct Neanderthals and Denisovans from Eurasia. It may have played a role in the successful spread of Homo sapiens out of Africa after about 60,000 years ago.

What does this tell us about human evolution and population migration?

Our work shows that some biological adaptations for becoming modern humans were unique to southern African hunter-gatherers who lived in a relatively large, stable population for many thousands of years south of the Limpopo River.

Co-author and geneticist from Uppsala University in Sweden, Carina Schlebusch, commented that

Because we now have more unadmixed ancient genomes from southern Africa, we are gaining better population-level insights, and a much clearer foundation for understanding how modern humans evolved across Africa.

Our findings contrast with linguistic, archaeological and some early genetic studies pointing to a shared ancestry or long-term interaction between different regions of Africa. Instead, it seems that southern Africa may have offered humans a climate and landscape refuge where hunter-gatherers thrived, adapting to a place rich in plant and animal resources for 200,000 years or more. During this time, we see no genetic evidence for incoming populations. Instead, sometime after about 100,000-70,000 years ago, small groups of southern African hunter-gatherers may have wandered northwards, carrying with them some of their genetic and technological characteristics.

According to population geneticist Mattias Jakobsson at Uppsala University,

these ancient genomes tell us that southern Africa played a key role in the human journey, perhaps ‘the’ key role.

Up to now, humans seemed to have developed their modern anatomical (physical) form before they developed modern behaviour and thinking. Learning more about ancient genes could help to close this gap, especially once more becomes known from genetic studies of other ancient African forager groups, and indigenous peoples elsewhere on the globe.

The Conversation

Marlize Lombard works for the University of Johannesburg. She received funding from the National Research Foundation of South Africa.

ref. Becoming human in southern Africa: what ancient hunter-gatherer genomes reveal – https://theconversation.com/becoming-human-in-southern-africa-what-ancient-hunter-gatherer-genomes-reveal-270378

Governments need to prepare for more frequent large floods

Source: The Conversation – Canada – By Samadhee Kaluarachchi, PhD Student in Forest Hydrology, University of British Columbia

Flood management is a priority for many governments around the world. Recent floods have led to hundreds of deaths and caused significant damage in Indonesia, Sri Lanka, Thailand, Vietnam, Albania, Kenya and elsewhere.

Canada too is no stranger to floods. Notably, in 2021, flooding in British Columbia cut off access to Metro Vancouver from the rest of the country and caused up to $14 billion in damages.

While many scientific and technical reports show that floods are becoming larger and more common, these reports may be underestimating how their frequency is changing. Flood sizes get the spotlight, however governments and experts need to also consider their frequency to address implications overlooked by traditional management methods.

Frequency and size together must tell the story, because even modest increases in size can lead to surprisingly big jumps in frequency. For example, timber harvesting in the B.C. Interior has led to a 19 to 26 per cent increase in flood size, and turned the former 100-year flood into a once-a-decade flood. Despite floods becoming more frequent, today’s practices still dominantly focus on flood size.

The consequences are severe. We can build infrastructure like dikes and dams bigger so they withstand larger once-in-a-century floods. But if we don’t capture how floods of all sizes (including the 100- and 200-year events) are becoming way more common, infrastructure can weaken and fail faster than we expect.

In our recently published study, we examined a range of scientific, technical and governmental documents to assess whether practices today help us reliably predict flood risks. We found that many of the factors contributing to the severity of a flood could respond much more strongly to climate and landscape changes than traditional methods imply, calling for change in our flood prediction practices.

We’re underestimating flood risk

tractors and diggers clear debris following a flood
Restoration work underway following November 2021 flooding damage at Tank Hill on Highway 1 in B.C.
(B.C. Ministry of Transportation and Transit/flickr), CC BY-NC-ND

Nature’s flood “ingredients” include rainfall, snow, soil wetness and energy for snowmelt, which combine in many “recipes” to trigger floods. Human influences like climate change, land use and land cover changes can alter these recipes, making floods bigger and more common. Understanding how human activity causes these effects on floods means predicting flood frequency and size together.

However, short flood records make it difficult to estimate the frequency and size of large floods. Without overcoming this challenge, assessments can produce unreliable results.

Additionally, many studies lump distant flood records with more recent records, suggesting that floods today have similar odds as those decades ago. Yet, experts agree that changes in the climate and landscape alter floods more strongly today.

These practices together produced a widespread perception in risk assessments where flood sizes rise rapidly, or steeply, per change in frequency (called a “heavier tail”).

Our recently published study challenges that perception, which implies that human influence shouldn’t greatly alter floods. In many places, human activities are making large floods more common. By giving little attention to how our activities affect flood frequencies, our practices don’t seem to capture just how sensitive floods are and how much they’re changing.

Without adapting our practices, we risk the loss of lives and livelihoods, misallocating funds, economic losses and lawsuits against governments, municipalities and professionals. Reliable flood projection and management is vital.

Considering flood frequency

To make reliable flood projections, we first need to identify a region’s natural flood frequencies and sizes, and which climate and landscape features drive them. With this solid baseline, we can determine how human activities shift flood frequencies and sizes, if floods are sensitive to human influence and what this means for society.

We can do this by predicting how different human activities affect floods through modelling or landscape experiments. We can work with flood records, using methods that recognize how current and future floods are far more affected by human activities than past floods.

We can use existing techniques to overcome challenges with short records and ensure that our estimates reflect a strong understanding of the natural and human drivers of flood frequencies and sizes.

By adopting stronger practices, our study predicts that many regions could see very different frequency-size relations: flood sizes could increase more slowly per change in frequency.

It signals a more “fragile,” or super sensitive, flood regime than what current methods imply. When we disturb the climate or landscape, large floods can react strongly; they become much more common, reflecting what we see in many places today.

This knowledge can help governments effectively manage the land while mitigating major jumps in flood frequency.

The way forward

Muddy floodwaters submerge a highway
Floodwaters wash away part of Highway 8 in B.C. in November 2021.
(B.C. Ministry of Transportation and Transit/flickr), CC BY-NC-ND

Effective flood management must include strong policies, nature-based solutions, and infrastructure designed for size and strength to withstand both larger and more frequent floods.

Nature-based solutions such as green areas, permeable surfaces and water-retaining features are being adopted by governments worldwide. Studies suggest that measures like increased forest cover have little impact on large floods; however, this may reflect the focus on flood size. Natural landscapes like forests can greatly reduce flood frequencies, even for very large floods.

In B.C., landscape features like mountains, forests, lakes, wetlands and floodplains spread out floods, lowering their peaks and making large events rarer. However, these same features make floods react strongly to changes in the climate and landscape.

Flood risk management must work with nature, maintaining or increasing the landscapes’ ability to store floodwaters. Our policies must address flood risk at the source through effective land management, recognizing that key causes of urban floods could lie thousands of kilometres away in the distant uplands. With strong policies and interventions both upstream and downstream, we can proactively manage floods.

The Conversation

Samadhee Kaluarachchi receives funding from the Natural Sciences and Engineering Research Council of Canada, the Faculty of Forestry at the University of British Columbia, the Gordon and Nora Bailey Fellowship in Sustainable Forestry, and the Mary and David Macaree Fellowship.

Younes Alila receives funding from Mitacs Canada and the Natural Sciences and Engineering Research Council of Canada.

ref. Governments need to prepare for more frequent large floods – https://theconversation.com/governments-need-to-prepare-for-more-frequent-large-floods-269251

FDA claims on COVID-19 vaccine safety are unsupported by reliable data – and could severely hinder vaccine access

Source: The Conversation – USA (3) – By Frank Han, Assistant Professor of Pediatric Cardiology, University of Illinois Chicago

The FDA has provided no evidence that children died because of receiving a COVID-19 vaccine. Anchiy/E+ via Getty Images

The Food and Drug Administration is seeking to drastically change procedures for testing vaccine safety and approving vaccines, based on unproven claims that mRNA-based COVID-19 vaccines caused the death of at least 10 children.

The agency detailed its plans in a memo released to staff on Nov. 28, 2025, which was obtained by several news outlets and published by The Washington Post.

Citing an internal, unpublished review, the memo, written by the agency’s top vaccine regulator, Vinay Prasad, attributes the children’s deaths to myocarditis, an inflammation of the heart muscle. And it says the deaths were reported to the Vaccine Adverse Event Reporting System, or VAERS, but provides no evidence that the vaccines caused the deaths.

The death of children due to an unsafe vaccine is a serious allegation. I am a pediatric cardiologist who has studied the link between COVID-19 vaccines and heart-related side effects such as myocarditis in children. To my knowledge, studies to date have shown such side effects are rare, and severe outcomes even more so. However, I am open to new evidence that could change my mind.

But without sufficient justification and solid evidence, restricting access to an approved vaccine and changing well-established procedures for testing vaccines would carry serious consequences. These moves would limit access for patients, create roadblocks for companies and worsen distrust in vaccines and public health.

In my view, it’s important for people reading about these FDA actions to understand how the evidence on a vaccine’s safety is generally assessed.

Determining cause of death

The FDA memo claims that the deaths of these children were directly related to receiving a COVID-19 immunization.

From my perspective as a clinician, it is awful that any child should die from a routine vaccination.

However, health professionals like me owe it to the public to uphold the highest possible standards in investigating why these deaths occurred. If the FDA has evidence demonstrating something that national health agencies worldwide have missed – widespread child deaths due to myocarditis caused by the COVID-19 vaccine – I don’t doubt that even the most pro-vaccine physician will listen. So far, however, no such evidence has been presented.

While a death logged in VAERS is a starting point, on its own it is insufficient to conclude whether a vaccine caused the death or other medical causes were to blame.

To demonstrate a causal link, FDA staff and physicians must align the VAERS report with physicians’ assessments of the patient, as well as data from other sources for monitoring vaccine safety. These include PRISM, which logs insurance claims data, and the Vaccine Safety Datalink, which tracks safety signals in electronic medical records.

It’s known that most deaths logged only in VAERS of children who recently received vaccines have been incorrectly attributed to the vaccines – either by accident or in some cases on purpose by anti-vaccine activists.

Heart-related side effects of COVID-19 vaccines

In his Substack and Twitter accounts, Prasad has said that he believes the rate of severe cardiac side effects after COVID-19 vaccination is severely underestimated and that the vaccines should be restricted far more than they currently are.

In a July 2025 presentation, Prasad quoted a risk of 27 cases per million of myocarditis in young men who received the COVID-19 vaccine. A 2024 review suggested that number was a bit lower – about 20 cases out of 1 million people. But that same study found that unvaccinated people had greater risk of heart problems after a COVID-19 infection than vaccinated people. In a different study, people who got myocarditis after a COVID-19 vaccination developed fewer complications than people who got myocarditis after a COVID-19 infection.

Existing vaccine safety infrastructure in the U.S. successfully identifies dangers posed by vaccines – and did so during the COVID-19 pandemic. Today, most COVID-19 vaccines in the U.S. rely on mRNA technology. But as vaccines were first emerging during the COVID-19 pandemic, two pharmaceutical companies, Janssen and AstraZeneca, rolled out a vaccine that used a different technology, called a viral vector. This type of vaccine had a very rare but genuine safety problem that was detected.

A report in VAERS is at most a first step to determining whether a vaccine caused harm.

VAERS, the Vaccine Safety Datalink, clinical investigators in the U.S. and their European counterparts detected that these vaccines did turn out to cause blood clotting. In April 2021, the FDA formally recommended pausing their use, and they were later pulled from the market.

Death due to myocarditis from COVID-19 vaccination is exceedingly rare. Demonstrating that it occurred requires proof that the person had myocarditis, evidence that no other reasonable cause of death was present, and the absence of any additional cause of myocarditis. These factors cannot be determined from VAERS data, however – and to date, the FDA has presented no other relevant data.

A problematic vision for future vaccine approvals

Currently, vaccines are tested both by seeing how well they prevent disease and by how well they generate antibodies, which are the molecules that help your body fight viruses and bacteria.

Some vaccines, such as the COVID-19 vaccine and the influenza vaccine, need to be updated based on new strains. The FDA generally approves these updates based on how well the new versions generate antibodies. Since the previous generation of vaccines was already shown to prevent infection, if the new version can generate antibodies like the previous one, researchers assume its ability to prevent infection is comparable too. Later studies can then test how well the vaccines prevent severe disease and hospitalization.

The FDA memo says this approach is insufficient and instead argues for replacing such studies with many more placebo-controlled trials – not just for COVID-19 vaccines but also for widely used influenza and pneumonia vaccines.

That may seem reasonable theoretically. In practice, however, it is not realistic.

Today’s influenza vaccines must be changed every season to reflect mutations to the virus. If the FDA were to require new placebo-controlled trials every year, the vaccine being tested would become obsolete by the time it is approved. This would be a massive waste of time and resources.

A pharmacy with a sign advertising flu shots
Influenza vaccines must be updated for every flu season.
Jacob Wackerhausen/iStock via Getty Images Plus

Also, detecting vaccine-related myocarditis at the low rate at which it occurs would have required clinical trials many times larger than the ones that were done to approve COVID-19 mRNA vaccines. This would have cost at least millions of dollars more, and the delay in rolling out vaccines would have also cost lives.

Placebo-controlled trials would require comparing people who receive the updated vaccine with people who remain unvaccinated. When an older version of the vaccine is already available, this means purposefully asking people to forgo that vaccine and risk infection for the sake of the trial, a practice that is widely considered unethical. Current scientific practice is that only a brand-new vaccine may be compared against placebo.

While suspected vaccine deaths should absolutely be investigated, stopping a vaccine for insufficient reasons can lead to a significant drop in public confidence. That’s why it’s essential to thoroughly and transparently investigate any claims that a vaccine causes harm.

Vaccine vs illness

To accurately gauge a vaccine’s risks, it is also crucial to compare its side effects with the effects of the illness it prevents.

For COVID-19, data consistently shows that the disease is clearly more dangerous. From Aug. 1, 2021, to July 31, 2022, more than 800 children in the U.S. died due to COVID-19, but very few deaths from COVID-19 vaccines in children have been been verified worldwide. What’s more, the disease causes many more heart-related side effects than the vaccine does.

Meanwhile, extensive evidence shows that COVID-19 vaccination reduces the risk of hospitalization by more than 70% and the risk of severe illness in adolescent children by 79%. Studies also show it dramatically reduces their risk of developing long COVID, a condition in which symptoms such as extreme fatigue or weakness persist more than three months after a COVID-19 infection.

Reporting only the vaccines’ risks, and not their benefits, shows just a small part of the picture.

The Conversation

I am a fellow of the American Academy of Pediatrics and regularly go on social media to share pro vaccine information.

ref. FDA claims on COVID-19 vaccine safety are unsupported by reliable data – and could severely hinder vaccine access – https://theconversation.com/fda-claims-on-covid-19-vaccine-safety-are-unsupported-by-reliable-data-and-could-severely-hinder-vaccine-access-271028

Así es la peste porcina africana que amenaza a España

Source: The Conversation – (in Spanish) – By Raúl Rivas González, Catedrático de Microbiología. Miembro de la Sociedad Española de Microbiología., Universidad de Salamanca

KACHALKIN OLEG/Shutterstock

La peste porcina africana ha entrado en España. El 27 de noviembre de 2025, España notificó su primer brote de peste porcina africana (PPA) desde 1994. Como consecuencia, este país ha perdido su estatus de país libre de PPA.

El número de casos positivos ha ido aumentando con el paso de los días. De momento, hay nueve jabalíes muertos por la enfermedad, todos en el municipio de Cerdanyola del Vallés (Barcelona). Los servicios veterinarios oficiales de Catalunya, en colaboración con el Ministerio de Agricultura, Pesca y Alimentación, han delimitado una zona de control y vigilancia en un radio de 20 kilómetros en torno a los casos detectados.

La campaña europea

En otoño de 2020, la Autoridad Europea de Seguridad Alimentaria (European Food Safety Authority, EFSA) lanzó una campaña, bautizada como “Alto a la peste porcina africana”, destinada a concienciar y sensibilizar a la población y a detener los graves brotes que surgían en el sudeste de Europa y que pueden amenazar gravemente la economía del continente. De momento, el éxito de la campaña es limitado, porque es evidente que la enfermedad continúa en expansión.

La peste porcina africana (PPA) es una devastadora enfermedad vírica, producida por un virus de ADN de la familia Asfarviridae y caracterizada por fiebres hemorrágicas, ataxia y depresión severa, que afecta a cerdos, jabalíes y a los parientes cercanos de la familia Suidae, con una tasa de letalidad de hasta el 100 %. Esta enfermedad afecta a todas las razas y tipos de cerdos domésticos y jabalíes europeos, y los animales de todas las edades son igualmente susceptibles al virus. Según la Organización Mundial de Sanidad Animal (OMSA), el virus de la peste porcina africana (PPA) es el patógeno más importante que afecta a la población porcina doméstica a nivel mundial.

Una de las carnes más consumidas

La enfermedad no tiene potencial zoonótico, porque no afecta al ser humano, pero el impacto socioeconómico que manifiesta es tremendo, porque el cerdo es una de las carnes más consumidas a nivel mundial.

Los cerdos son una fuente primaria de ingresos domésticos en muchos países y suponen una de las principales fuentes de proteínas animales, representando más del 35 % de la ingesta mundial de carne. En 2024, la UE produjo una cantidad provisional de 21,1 millones de toneladas de carne de cerdo. Los dos principales países productores de carne de porcino de la UE son, precisamente, España (5,0 millones de toneladas en 2024) y Alemania (4,3 millones de toneladas)

Durante la última década, la peste porcina africana ha pasado de ser una enfermedad regional del África subsahariana a erigirse como una amenaza considerable y tangible para la cría de cerdos, especialmente en Europa y en Asia. Su propagación ha devastado las granjas porcinas gestionadas por familias, a menudo el pilar del sustento de las personas. Como efecto colateral, ha reducido las oportunidades de acceder a la atención médica y a la educación en países pobres.

Europa, China y Vietnam

Desde enero de 2022, en Europa más de 1,5 millones de cerdos domésticos han muerto o han tenido que ser sacrificados o eliminados por causa de la peste porcina africana, para lq que no existe una vacuna eficaz.

En agosto del año 2018 apareció un gran brote de PPA en China, el mayor productor y consumidor de carne porcina del mundo, que obligó a los productores chinos a sacrificar a más de 200 millones de cerdos y supuso una pérdida económica del 0,78 % en el producto interior bruto chino del año 2019. Esto tuvo un importante impacto desacelerador en la economía china y afectó a los mercados cárnicos a nivel mundial, representando una fuerte amenaza para el suministro global de carne de cerdo.

En cuanto al brote de peste porcina africana que sufrió Vietnam en el año 2019, provocó una disminución del PIB del país de al menos un 0, %.

El PPA tiene 24 genotípos diferentes

El virus tiene 24 genotipos descritos, basados en la secuenciación del gen de la proteína de la cápside p72 del ASFV (siglas de African swine fever virus).

El genotipo I del virus de la peste porcina africana es endémico en Cerdeña. El genotipo II del virus fue introducido en el año 2007 en Georgia y desde allí se propagó a través de la región del Cáucaso, afectando a Armenia, Azerbaiyán, Rusia, Ucrania, Bielorrusia, Lituania, Letonia, Polonia, Estonia, Moldavia, la República Checa y Rumania, donde el virus continúa circulando.

El virus de la peste porcina africana hallado en jabalíes en España es el genotipo II, el mismo que circula en Europa.

Ojo con los productos cárnicos infectados

El virus de la PPA es muy resistente en el medio ambiente y en los productos porcinos, lo que significa que puede sobrevivir en la ropa, botas, ruedas y otros materiales y cruzar fronteras si no se toman las medidas adecuadas. Así, la transmisión de un país a otro puede verse facilitada por los viajeros que llevan cerdos infectados o productos porcinos contaminados y no los declaran a las autoridades.

Como se trata de un virus resistente a un amplio rango de pH y a ciclos de congelación y descongelación, puede permanecer infeccioso durante muchos meses a temperatura ambiente o almacenado a 4 °C. El virus presente en fluidos corporales y suero se inactiva a 60 °C en 30 minutos. Sin embargo, el virus presente en carne de cerdo sin procesar, donde puede permanecer viable durante varias semanas o meses, solo se inactiva calentándolo a 70 °C durante 30 minutos.

Se considera que la principal vía de infección por el virus de la peste porcina africana (PPA) es la ingesta de productos de animales infectados o material contaminado con el virus, como restos de comida o desperdicios que contengan carne de cerdo o productos cárnicos infectados.

Esta ruta es especialmente relevante para la propagación en jabalíes, debido a sus hábitos carroñeros o muy oportunistas a la hora de buscar comida, razón por la cual frecuentan la basura. Otras vías de transmisión importantes incluyen el contacto directo entre animales infectados (cerdos o jabalíes) y sanos (a través de fluidos corporales como saliva, orina, heces, secreciones nasales), el contacto indirecto a través de fómites (ropa, vehículos, equipos, calzado, pienso contaminado) y, en ciertas regiones, la picadura de garrapatas blandas del género Ornithodoros que actúan como vectores biológicos.

La persistencia del virus en el medio ambiente y en productos cárnicos (incluso curados, congelados o refrigerados) hace que estas vías de infección indirectas sean particularmente peligrosas y difíciles de controlar.

El aumento en el número de países infectados representa una amenaza significativa debido a la posible introducción del virus de la peste porcina africana en países libres de la enfermedad, ya sea a través de poblaciones de jabalíes salvajes o de la importación y el comercio legales e ilegales de productos y desechos de cerdo contaminados. Dado que los efectos de un brote de peste porcina africana pueden ser devastadores, la prevención, la detección y la información son esenciales para evitar la propagación y poder contener la enfermedad.

The Conversation

Raúl Rivas González no recibe salario, ni ejerce labores de consultoría, ni posee acciones, ni recibe financiación de ninguna compañía u organización que pueda obtener beneficio de este artículo, y ha declarado carecer de vínculos relevantes más allá del cargo académico citado.

ref. Así es la peste porcina africana que amenaza a España – https://theconversation.com/asi-es-la-peste-porcina-africana-que-amenaza-a-espana-271230

El imparable triunfo del fútbol femenino español

Source: The Conversation – (in Spanish) – By Pedro César Martínez Morán, Director del Master in Talent Management de Advantere School of Management / Profesor asociado de la Facultad de Ciencias Economicas y Empresariales, Universidad Pontificia Comillas

La selección femenina de España celebra su victoria en la final de la Women’s Nations League el 2 de diciembre. RTVE

Al ganar su segunda Women’s Nations League, la selección femenina de fútbol de España se sucede a sí misma. En 2023, también subió a lo más alto del pódium en el Campeonato Mundial, la primera final en la que participaban. En estos escasos años, tan solo se le ha escapado conseguir medalla en los pasados Juegos Olímpicos.

Cambio de paradigma

En este siglo XXI, España brilla en un conjunto amplio de disciplinas. Tanto es así que en abril de 2025 se han superado por primera vez los 6 000 deportistas de alto nivel, según recoge el Consejo Superior de Deportes.

No obstante, el fútbol acapara todas las atenciones. Según la compañía de marketing deportivo SportsValue, de las diez competiciones deportivas con mayor generación de ingresos en el mundo, cinco se relacionan con este deporte.

La liga masculina de fútbol de España ocupa un meritorio noveno lugar, y en la competición que gestiona juegan el primero y el sexto equipos del mundo por ingresos. Es el deporte más popular en este país.

Sin embargo, hasta épocas recientes, las selecciones nacionales asomaban muy poco la cabeza en los rankings correspondientes. Se atribuye a Alfredo Di Stefano la frase lapidaria de “jugamos como nunca y perdimos como siempre”. Incluso, se publicó un libro con ese título. Eran otros tiempos.

La eclosión del fútbol femenino

La selección española ganó todos los partidos de la última Eurocopa femenina, aunque perdiese el más importante. Si bien en la fase de grupos sus rivales le marcaron algún gol, en los partidos decisivos, los previos a la final, mantuvo su portería a cero. Su planificación ha brillado. El gol en la semifinal ante Alemania, a la que nunca se había derrotado, no fue debido al azar: según comentó la jugadora Aitana Bonmati, “lo habían estudiado”.

En las categorías inferiores, España ocupa el segundo lugar en el ranking de campeonatos europeos ganados en sub-17. En el caso de las sub-19, es el país con más trofeos conquistados.

Por el lado individual, las jugadoras españolas lideran el ranking de balones de oro. Bonmatí y Alexia Putellas sobresalen. Además, las licencias de fútbol femenino en España casi se han multiplicado por tres en el intervalo 2012 a 2024.

Mientras las audiencias televisivas de la semifinal de la Eurocopa alcanzaron cifras muy altas, el partido de vuelta frente a Alemania en la final de la Women´s Nation League registró la mejor entrada a un partido de fútbol femenino en España.

Qué es el fútbol

El fútbol son muchas cosas, demasiadas: juega un rol significativo en la vida diaria. El historiador británico David Goldbaltt incluso llega a aseverar que es “el reflejo más extraordinario de la sociedad”. Estrechamente ligado a la política y a los medios de comunicación, a menudo se utiliza como herramienta de expresión política y de socialización, incluso como medio para moldear la opinión pública y la identidad.

Lo importante en el fútbol, en opinión de Luis Aragonés, futbolista y luego entrenador, es ganar, ganar y volver a ganar. La victoria produce titulares, mientras que la derrota genera abandono.

Aportación de España: talento y perseverancia

El talento individual y el colectivo caminan por senderos diferentes. Según Pablo Atela y Fernando Díez, el primero se puede asociar a creatividad, habilidades superiores al promedio y compromiso con la tarea. El segundo conecta con la cooperación y la armonía social.

En 2007, la psicóloga norteamericana Angela Duckwort, junto con un equipo de expertos, reveló el papel crucial que tiene la determinación en el éxito. Unos años más tarde, en 2016, publicó un libro –Grit: el poder de la pasión y la perseverancia– donde dejaba de manifiesto cómo la resiliencia y la fuerza de voluntad para alcanzar metas resultan tan importantes como el propio talento.

Según BBC Sports, los éxitos del fútbol femenino español han venido de una mezcla entre familiaridad y continuidad. Por su parte, el diario británico The Guardian, justo antes de comenzar la Eurocopa femenina, titulaba que los problemas acontecidos tras ganar el Campeonato del mundo resultaron un revulsivo para transformar el fútbol femenino español.

España gusta

En definitiva, los triunfos futbolísticos de las jugadoras españolas resuenan en el escaparate internacional: a los espectadores de este deporte les gusta como juega España.

Tras superar polémicas y numerosas dificultades, la selección rezuma alegría, simplicidad, desparpajo. En lo estrictamente deportivo juegan como nadie y durante estos últimos años le han tomado la medida a la victoria. A eso hay que sumar el gran trabajo que se está haciendo categorías inferiores. Su rendimiento colectivo demuestra el valor del talento grupal y la gran preparación técnica y táctica a nivel individual.

The Conversation

Pedro César Martínez Morán no recibe salario, ni ejerce labores de consultoría, ni posee acciones, ni recibe financiación de ninguna compañía u organización que pueda obtener beneficio de este artículo, y ha declarado carecer de vínculos relevantes más allá del cargo académico citado.

ref. El imparable triunfo del fútbol femenino español – https://theconversation.com/el-imparable-triunfo-del-futbol-femenino-espanol-271219

Doctrina Monroe: más de dos siglos de “América para los americanos”

Source: The Conversation – (in Spanish) – By Deborah Besseghini, Doctora Investigadora Marie Curie – Departamento de Geografía, Historia y Filosofía – Historia Moderna, Universidad Pablo de Olavide

Ilustración satírica de 1896 donde se ve al Tío Sam interponiéndose entre las potencias europeas y unos personajes que representan a Nicaragua y Venezuela. Wikimedia Commons

El 24 de noviembre venció el ultimátum a Nicolás Maduro por el que Estados Unidos clasificó al llamado Cártel de los Soles como organización terrorista, allanando el camino para una posible intervención militar contra Venezuela.

Esa decisión parece menos una exigencia jurídica que una advertencia política.
Como ya se vio en la “guerra de los doce días” contra Irán, que llevó a casi toda la UE a aceptar las exigencias estadounidenses en el marco de la OTAN, Washington se preocupa cada vez menos por sustentar sus ataques mediante justificaciones normativas.

Acoso diplomático

Los detractores del presidente Trump sostienen que ha convertido a EE.UU. en un “Estado mafioso” (mafia state), debido a que recurre a prácticas gansteriles, tanto a nivel internacional como nacional. Para estas voces críticas, Trump busca la cooperación o el sometimiento mediante la amenaza del uso de la fuerza.

No hace falta simpatizar con Maduro para ver los riesgos de este acoso diplomático “bully diplomacy”. Por exitosa que haya sido hasta ahora, socava los ya frágiles cimientos del orden mundial normativo (rule-based global orden) que Occidente dice defender. Sus efectos resultan difíciles de prevenir.

Esto sucede en el aniversario de la llamada doctrina Monroe, que tuvo lugar el 2 de diciembre.

A todos nos suena el lema “América para los americanos” y ahora lo asociamos con el control de fronteras y el proteccionismo industrial. Sin embargo, no es la primera vez que se alzan banderas con este lema.

1823 fue el marco de una auténtica partida de ajedrez geopolítico. Más de dos siglos después del mensaje del presidente James Monroe, resulta útil conocer cómo Londres y Washington compitieron por la proyección política en Latinoamérica. Entender qué ocurrió y cómo Europa perdió gradualmente capacidad de influencia puede ayudarnos a leer mejor lo que se avecina.

El giro intervencionista de la doctrina Monroe

Monroe no podía prever que su declaración contra la injerencia europea en los países independientes de América y a favor del no-intervencionismo estadounidense en Europa (en Grecia, por ejemplo) se transformaría en una “doctrina” útil para justificar no solo el aislacionismo, sino también el intervencionismo en América y más allá.

Sin embargo, el germen de ese giro ya estaba inscrito en el propio mensaje de 1823.

Aquel año, la contrarrevolución alcanzaba su cenit con la invasión francesa de España, que restauró el absolutismo en Europa y parecía anunciar una intervención franco-española en América.

Cuando Monroe leyó su mensaje, Gran Bretaña ya había asegurado el gradual reconocimiento de la independencia hispanoamericana, publicando el compromiso francés a la no-intervención en América que recoge el Memorándum de Polignac. Este hecho constituyó una parte del proceso para la difícil aceptación británica de la intervención francesa en España.

Pero Washington lo desconocía. Como subrayan los expertos, la declaración de Monroe no representó una ambigua cooperación con Londres, sino una potente reacción negativa a un anterior pedido británico de colaboración sobre la independencia latinoamericana.

Fue, en esencia, un manifiesto de emancipación geopolítica.

El secretario John Quincy Adams, autor del documento, se oponía a la propuesta británica de declarar que ni Gran Bretaña ni EE. UU. anexarían territorios previamente españoles, porque pensaba que Londres quería limitar la proyección estratégica de la república. Su negativa contenía en esencia la ideología del “destino manifiesto” y un panamericanismo contradictorio.

Considerando cómo los conflictos imperiales del siglo XVIII habían perturbado la geografía continental, Adams quiso establecer que los territorios americanos ya no eran peones en el ajedrez europeo.

El mensaje de Monroe no fue una herramienta de política interna, como se ha dicho, sino que dejó claro al mundo que EE.UU. interpretaría cualquier amenaza europea a las independencias hispanoamericanas como un ataque a su propia seguridad y paz.

Percibía como interferencia los planes para crear monarquías independientes, porque nuevos lazos dinásticos habrían arrastrado a América a conflictos europeos. Por eso, la “libertad hemisférica” tenía que ser republicana.

Aguafuerte coloreado a mano de Charles Williams, en el que se ironiza sobre una derrota naval británica durante la Guerra de 1812.
Library of Congress

EE. UU. terminó legitimando como defensiva su teórica intervención contra la interferencia de otras potencias en otros países. Poco importó que careciera de la fuerza y la voluntad de materializar la amenaza. Fue una herramienta propagandística en Latinoamérica, que tuvo profundos efectos en México y Texas. Creó graves divisiones internas entre conservadores probritánicos y liberales proestadounidenses y empujó la reacción británica, una dinámica observada previamente en Sudamérica durante la Guerra de 1812.

Pero al intentar debilitar a la influencia europea, EE. UU. no quería actuar como guía del mundo americano.

El origen del “patio trasero”

Los límites de la declaración de Monroe residían, contrariamente a lo que se cree, en la reticencia de EE. UU. a gobernar un continente que solo deseaba controlar en la medida necesaria para su seguridad. Hispanoamérica representaba un escudo frente a la amenaza europea, la barrera entre el hogar y el mundo. Era su “patio trasero”. Con el tiempo el “hogar” se expandiría al jardín, y el jardín se proyectaría sobre el resto del mundo entre muchas contradicciones. Pero EE. UU. no perdería su hábito, fijado ya en 1823, de interpretar la injerencia ajena en territorios externos como una amenaza directa a su propia seguridad.

Y así como en el siglo XIX no quería gobernar el caos americano, hoy no quiere gobernar el mundo ni Occidente. Como conclusión, la “bully diplomacy” de Trump encarna el lado oscuro de una potencia militar hegemónica que no quiere ser un imperio, sino seguir preservándose a sí misma.

The Conversation

Deborah Besseghini es doctora investigadoras Marie Curie en la Universidad Pablo de Olavide de Sevilla, donde desarrolla el proyecto “UNWANTED – The Revolutionary Impact of Financing a Global War, 1797-1825”, financiado por la Comisión Europea.
Algunos artículos citados son parte de un numero monográfico sobre la Doctrina Monroe en el cual la investigadora participó.

ref. Doctrina Monroe: más de dos siglos de “América para los americanos” – https://theconversation.com/doctrina-monroe-mas-de-dos-siglos-de-america-para-los-americanos-270607