Qué es lo extraño en 3I/ATLAS, el objeto interestelar más observado del mundo

Source: The Conversation – (in Spanish) – By Josep M. Trigo Rodríguez, Investigador Principal del Grupo de Meteoritos, Cuerpos Menores y Ciencias Planetarias, Instituto de Ciencias del Espacio (ICE – CSIC)

Vista superior de la Vía Láctea que muestra las órbitas del Sol (líneas punteadas amarillas) y la del cometa 3I/ATLAS (líneas discontinuas rojas). M. Hopkins/Ōtautahi-Oxford team ESA/Gaia/DPAC, CC BY-SA

Mucho se ha escrito en prensa durante las últimas semanas del cometa 3I/ATLAS, sobre la supuesta incertidumbre en su naturaleza. El seguimiento realizado con todo tipo de instrumentación lo convierten en el objeto interestelar mejor observado hasta la fecha. Y, pese a las muchas elucubraciones vertidas, tanto las imágenes como los espectros de reflexión apuntan claramente a su naturaleza cometaria. No es en ningún caso un extravagante objeto desconocido para la ciencia.

De hecho, nuestro grupo de investigación sobre Asteroides, Cometas y Meteoritos en el ICE-CSIC/IEEC le ha seguido la pista desde los primeros días, midiendo su posición y obteniendo precisas medidas fotométricas. Ya en imágenes obtenidas el 5 de julio con el Telescopio Robótico Joan Oró podía apreciarse su coma, característica de los cometas.

Más parecido a un asteroide que a un cometa

En un nuevo trabajo, liderado por la profesora Bin Yang de la Universidad Diego Portales de Chile, publicado en ArXiv, se ha empleado instrumentación puntera en los telescopios Gemini-S/GMOS y NASA IRTF/SpeX. Los días 5 y 14 de julio de 2025 obtuvieron espectros del objeto tras su descubrimiento, tanto en la banda visible como en el infrarrojo cercano.

Esas observaciones se realizaron al poco de ser detectado, evitando así que la actividad del cometa asociada a la sublimación de hielos apantallase otros aspectos de su naturaleza.

Sin espacio para la duda, ambos espectros apuntan a que el objeto interestelar es un cometa.

En el rango óptico, 3I/ATLAS muestra una pendiente enrojecida que lo asemeja al de ciertos asteroides de nuestro sistema solar de clase espectral D. Se trata de asteroides muy oscuros (albedo bajo), con un espectro muy rojo y una composición rica en carbono. Son raros y tienen poca reflectividad.

El espectro en la ventana del infrarrojo cercano de 3I/ATLAS se aplana significativamente, aproximadamente a una tasa de 0.9 a 1.5 micrones, similar al comportamiento espectral de grandes granos de hielo de agua en la coma de los cometas.

Los autores del trabajo, entre los que se encuentra la prestigiosa astrobióloga Karen J. Meech, modelaron el comportamiento espectral del cometa 3I/ATLAS. Emplearon una mezcla de polvo al 70 % del del meteorito (condrita carbonácea) Tagish Lake y un 30 % de hielo de agua con un tamaño medio de 10 micras. De hecho, esa fracción de hielo del ~30% obtenida podría interpretarse como una estimación aproximada de la composición de la coma.

En general, todos los estudios y observaciones realizadas hasta la fecha apuntan a que es un cometa interestelar activo que contiene abundante hielo de agua, con una composición de polvo más similar a la de los asteroides tipo D que a la de los objetos transneptunianos. Esto podría ser consistente con la idea de que se formase en una región interior de un sistema planetario, siendo expulsado por un tirón gravitacional experimentado en su encuentro con un planeta. En cualquier caso los escenarios permanecen abiertos pues cabrá esperar a las observaciones que realicen diversas sondas espaciales del intruso, siendo la misión Psyche de la NASA la major situada.

La coma del cometa 3I/ATLAS

También se ha especulado con la idea de que el 3I/ATLAS no presenta una coma extendida como otros cometas, pero esa idea es falsa. Básicamente, siendo un objeto cuyo diámetro es de pocos kilómetros, no lo hubiéramos descubierto sin haber presentado esa envoltura que llamamos coma y que lo hace visible a miles de millones de kilómetros.

La coma posee una composición que sería representativa del material sublimado pero quizás no del interior mismo del objeto. La componente gaseosa de la coma está dominada por dióxido de carbono, produciendo una envoltura de unos 350.000 km alrededor del núcleo cometario.

Dicha envoltura además del gas contiene partículas de polvo de tamaño micrométrico que se desprenden del cometa debido a la sublimación de los hielos. El polvo está embebido entre los materiales helados que son calentados en su acercamiento al Sol. En el caso de un cometa interestelar deberíamos esperar un manto irradiado por rayos cósmicos a lo largo de los miles de millones de años que lleva circulando por la Vía Láctea. Quizás por esa razón su actividad cometaria aparezca aletargada y restringida en volátiles.

Las observaciones infrarrojas muestran que la componente sólida de la coma, desprendida por la presión hacia afuera del gas sublimado aparece dominada por pequeñas partículas de hielo de agua y polvo que se asemeja a una clase de meteorito asociado a las condritas carbonáceas, procedentes de un tipo de objetos llamados transicionales: a mitad de camino entre un asteroide y un cometa.

Así pues 3I/ATLAS no tiene nada de extraño, salvo que se trata de un material que nos resulta familiar pese a haberse formado necesariamente en un lejano sistema planetario.

The Conversation

Josep M. Trigo Rodríguez recibe fondos del proyecto del Plan Nacional de Astronomía y Astrofísica PID2021-128062NB-I00 financiado por el MICINN y la Agencia Estatal de Investigación.

ref. Qué es lo extraño en 3I/ATLAS, el objeto interestelar más observado del mundo – https://theconversation.com/que-es-lo-extrano-en-3i-atlas-el-objeto-interestelar-mas-observado-del-mundo-264219

Donald Trump was once India’s best friend. How did it all go wrong?

Source: The Conversation – Global Perspectives – By Ian Hall, Professor of International Relations, Griffith University

Just months into President Donald Trump’s second term in office, one of the United States’ most important strategic partnerships is in crisis.

Relations between the US and India are at their lowest ebb in a quarter of a century. Things are so bad that Indian Prime Minister Narendra Modi has reportedly refused to accept calls from Trump for more than two months.

In recent days, Trump labelled trade ties with India a “totally one-sided disaster” and a report emerged that he is no longer planning to visit India later this year for a summit of the Quad partners (India, the US, Australia and Japan).

So bad, so quickly

Things were not meant to happen this way. Many in New Delhi were delighted when Trump won the election last year. Modi congratulated his “friend” on X, along with pictures of the two embracing and holding hands.

India’s foreign minister, S. Jaishankar, told journalists that while other countries might be “nervous” about Trump’s return, India was not.

Feeling confident, Modi went to Washington to meet Trump days after his return to office. The encounter did not go well.

On the eve of the meeting, Modi was embarrassed by distressing images of Indian nationals, handcuffed and shackled, being deported from the US on a military aircraft.

In the Oval Office, he promised to buy more US arms, oil and gas, and asked that Trump not impose punitive tariffs on India. Modi failed to get that commitment.

A few weeks later, Trump announced India would be hit with a 27% tariff – far higher than the 10% imposed on China – unless it could negotiate something better.

Crisis in Kashmir

Begrudgingly, New Delhi began to talk trade. US Vice President JD Vance visited India in late April and both sides made positive noises about a deal. But while Vance was in town, India was engulfed in a new crisis.

On April 22, terrorists killed 26 people – mostly Hindu tourists – in Kashmir, long the site of simmering conflict between India and Pakistan. The Modi government pledged to respond with force, as it had done in the past after similar incidents.

On May 7, India bombed what it claimed were militant camps in Pakistan and Pakistan-administered Kashmir. A rapidly escalating, unpredictable conflict followed, as both sides used drones and missiles to attack one another.

Alarmed, governments around the world urged the two nuclear-armed states to end hostilities before matters got out of control. Early in the morning on May 10, they did, and agreed to a ceasefire.

Trump anoints himself peacemaker

Before either the Indian or Pakistani governments had a chance to say anything, Trump stepped in to take credit.

On social media, he announced both sides had agreed a deal. The next day he claimed they would soon sit down with him as mediator and find a solution to the Kashmir conflict.

Islamabad was jubilant at this outcome. New Delhi, meanwhile, was furious.

India’s longstanding view is that the Kashmir dispute must be settled bilaterally, without third-party involvement. The US has accepted this position for more than 20 years. Now it appeared Trump was taking a different view.

This put Modi in a bind. Keen to maintain a mutually beneficial partnership and avoid punitive tariffs, he did not wish to upset Trump.

But he could not acknowledge Trump’s claims without setting aside a fundamental principle of Indian policy. So, Modi called Washington and explained he would not accept mediation over Kashmir.

The final straw

Meanwhile, Pakistan saw an opportunity to win favour in Washington and drive a wedge between the US and India.

Recognising that Trump covets a Nobel Peace Prize, Islamabad nominated him for his supposed role in ending the conflict.

Enthused, Trump called Modi on June 17 and asked him to do the same. Worse still, Trump requested Modi stop in Washington on the way back from the G7 summit in Canada, and meet with Pakistan’s military chief, Asim Munir.

According to a recent report, that was the final straw for Modi. He flatly refused both requests. The two men reportedly haven’t spoken since.

Piqued, Trump responded by punishing India for continuing to buy Russian oil by lifting its tariff rate to 50% and postponing trade talks.

New Delhi’s dilemma

Trump’s actions have ordinary Indians seething and demanding action, but the Modi government does not have good options.

Giving in to coercion would make Modi – dubbed by political opponents “Narender Surrender” – look weak. Yet, no other major power can offer India what it needs in terms of markets, investment, technology, weapons and diplomatic support.

With US-India relations strained, New Delhi has been working hard to stabilise its relationship with China, which has been tense since bloody border clashes between the two in 2020.

Modi went to China for the first time in seven years on August 31 to further that aim, shaking hands with President Xi Jinping. But although Xi emphasised the need for amicable ties – he said the “elephant and dragon should dance together” – there is little trust between India and China at present.

Modi has more faith in Russia. In China, Modi and Russian President Vladimir Putin reportedly spoke for nearly an hour in Putin’s limousine. And Modi will host the Russian leader for more talks in India later this year. However, Russia remains a pariah in Europe, with limited means to help.

Other countries, like Japan, where Modi stopped off on his way to China, could also help India navigate the current crisis. But they do not have the clout to resolve it.

Unless Modi can find a way to win Trump back, India’s next few years could be very difficult.

The Conversation

Ian Hall has received funding from the Australian Research Council, Department of Defence, and Ministry of Foreign Affairs of Japan. He is an honorary Academic Fellow of the Australia India Institute.

ref. Donald Trump was once India’s best friend. How did it all go wrong? – https://theconversation.com/donald-trump-was-once-indias-best-friend-how-did-it-all-go-wrong-264272

Trump’s tariffs are headed to the US Supreme Court, prolonging the chaos on trade

Source: The Conversation – Global Perspectives – By Felicity Deane, Professor of Trade Law and Taxation, Queensland University of Technology

Trading partners of the United States are facing a fresh period of uncertainty after a US federal appeals court ruled President Donald Trump’s “reciprocal” tariffs were illegal.

In a 7-4 majority, the judges ruled Trump had exceeded his power by invoking emergency powers to impose tariffs of “unlimited duration on nearly all goods from nearly every country in the world”, upholding an earlier court decision.

The ruling will throw into disarray the strategies of trading partners still in negotiations with the US, who may decide to wait and see the outcome of the legal battle.

Although there are different options available to challenge the decision, Trump has made it clear the next stop will be the Supreme Court.

The US Court of Appeals for the Federal Circuit said the tariffs would remain in place until October 14, to allow time for further appeals.

The power to tax rests with Congress

The ruling tested the limits of executive power under the International Emergency Economic Powers Act (IEEPA) from 1977. Trump is the first president to use this act to impose tariffs, setting the stage for a test of executive power. At least for now, it is a test the administration appears to have failed. The judges rejected Trump’s interpretation, which they said would place no limit on the president to raise revenue without any authorisation from Congress.

Citing Article 1, section 8, of the US Constitution, the majority judgement unequivocally stated that “tariffs are a tax” and the power to tax under the Constitution rests with Congress.

In upholding an earlier decision by the Court of International Trade, the appeals court majority noted:

if the President can declare an emergency to cut the deficit by raising taxes in whatever way he wishes, not much remains of Congressional authority over taxation.

The tariffs are still in place

There were two important outcomes from this latest decision. First, the “liberation day” tariffs are (currently) deemed illegal. Second, these “illegal” tariffs will temporarily stay in place to allow for the appeal options to be explored.

Revenue will continue to be collected under the executive orders in question. Should the tariffs be deemed illegal on appeal, that revenue may need to be returned.

This ruling does not apply to all tariffs. It doesn’t cover specific sector tariffs such as those on aluminium and steel. However, other tariffs imposed during the first Trump presidency have already been ruled illegal under World Trade Organization rules and are currently the subject of appeal under the multilateral dispute settlement system.

The latest ruling would not reverse the decision to suspend the de minimis exception that caused global postage chaos. However, if the ruling is upheld, the rate of tariffs on low-value goods would revert back to pre-“liberation day” percentages. In many instances, this would mean back to zero.

What about the deals?

Trading partners initially responded with panic to the unveiling of Trump’s chaotic tariff agenda in April. There was a rush to meet with the president and make so-called deals. So what should governments of trading partners do now?

The most logical response might be to wait out the US legal process, because there may be no point in making deals if the tariffs are upheld to be illegal.

Unfortunately, this means continued uncertainty for business. On one hand, the courts may determine the tariffs are unlawful and must therefore be revoked. But Congress could subsequently move to reimpose tariffs with fresh legislation, or Trump could try other legal avenues.

The Constitution vs loyalty to Trump

If the administration does decide to appeal to the Supreme Court, the important test will not necessarily be about tariffs but whether the US Constitution will continue to support the separation of powers.

The appeals court decision argues the IEEPA does not support the introduction of tariffs of the magnitude of the “liberation day” tariffs. What the IEEPA does allow is for the president to “regulate […] importation”. However, the court suggested this phrase is nothing more than

a wafer-thin reed on which to rest such sweeping power.

Although the appeals court noted that such arguments have been rejected by the Supreme Court in the past, we will have to wait and see whether it is a “wafer-thin reed” that will become doctrine.

The Supreme Court has a conservative majority, with six of nine judges appointed by Republicans, including three in Trump’s first term.

The Supreme Court has already granted the president immunity from prosecution in some circumstances. If the majority decides to allow these widespread and indefinite tariffs, they may be one step closer to creating an American monarch.

The Conversation

Felicity Deane does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.

ref. Trump’s tariffs are headed to the US Supreme Court, prolonging the chaos on trade – https://theconversation.com/trumps-tariffs-are-headed-to-the-us-supreme-court-prolonging-the-chaos-on-trade-264249

China may not invade Taiwan, but rather blockade it. How would this work, and could it be effective?

Source: The Conversation – Global Perspectives – By Claudio Bozzi, Lecturer in Law, Deakin University

US officials believe Chinese President Xi Xinping has set a deadline for his military to be capable of invading Taiwan by 2027 – the centennial anniversary of the founding of the People’s Liberation Army (PLA).

US Secretary of Defense Pete Hegseth mentioned this date at a security conference in Singapore in May, warning of the “imminent threat” China poses to Taiwan.

The PLA has invested heavily in expanding and modernising its operations in recent years. Since 2015, it has built the world’s largest navy and coast guard.

But rather than threaten an invasion of Taiwan, China seems increasingly likely to pressure the self-governing, democratically ruled island with an extended blockade to force it to capitulate.

In preparation for such a possible action, China has developed a new command structure enabling it to coordinate its air, sea and land-based weapons systems to enact a strategy of lianhe fengkong (联合封控), or joint blockade. This would effectively cut Taiwan off from the outside world.

In late July, the Centre for Strategic and International Studies (CSIS) produced a report on 26 simulated war games it conducted to determine what a Chinese blockade of Taiwan would look like.

Taiwan’s natural gas supplies were predicted to run out after ten days of a blockade. Coal and oil supplies would run out in a matter of weeks. If Taiwan’s electricity was reduced to 20% of its pre-blockade levels, all manufacturing would cease. Casualties were expected to be in the thousands.

Taiwan is particularly vulnerable to a blockade. It relies more than any other developed nation on port calls relative to the size of its economy. Its biggest ports are on its west coast, facing mainland China. The island also has limited emergency food and fuel reserves.



What is a blockade under the law?

Imposing a naval blockade during armed conflict is an established right under customary international law. Blockades are not illegal per se, but they must comply with the laws of war. It’s a complicated and controversial area of the law.

To be legal, a blockade must first be effective. That is, the blockading power must maintain a force that prevents access to the enemy’s coast.

Other nations must be notified of the instigation of the blockade and its geographical extent.

A blockade must be enforced impartially against all vessels, except neutral vessels in distress. Any vessel breaching the blockade would be subject to being stopped, captured or fired upon.

Lastly, a blockade cannot prevent access to neutral ports or the delivery of humanitarian assistance to civilians.

Blockade strategies

China may use one of several blockade strategies against Taiwan. In contrast to an invasion, blockades can be scaled up or back, or reversed, depending on the unfolding security situation.

For instance, China may attack merchant shipping vessels seeking to enter Taiwanese waters to deliver essential cargo, coercing Taiwan to submit to China’s takeover. This is known as a kinetic blockade.

Alternatively, it may implement its preferred strategy of “winning without fighting”. Given the sheer size of its navy, coastguard and maritime militia, China could simply encircle the island and block access to its ports.

This could isolate Taiwan from the global economy to the point of forcing it to surrender, or weaken it sufficiently to enable an invasion, without engaging in open hostilities. This is a non-kinetic blockade.

Other ways of impeding naval passage

China may also use measures that fall short of a blockade, but have similar effects. It has passed a suite of domestic laws that legitimise military and non-military aggression of this kind.

For example, the navy or coast guard may:

  • lay mines in the sea without declaring a formal blockade
  • establish maritime danger or exclusion zones for foreign ships, and
  • intercept, detain and regulate foreign vessels.

These tactics would only be effective because China’s domestic laws have exploited ambiguities in jurisdiction over its surrounding waters.

For example, China has passed laws requiring notification from foreign vessels if they enter waters it considers its own and under its control, and allowing its ships to alter or suspend maritime traffic for security or military purposes.

Those powers, however, are inconsistent with international law. China, for example, considers the Taiwan Strait as Chinese territory. Under the UN Convention on the Law of the Sea, however, the strait is considered international waters, which enables freedom of navigation for all vessels.

Also, creating an unstable security environment around Taiwan (similar to what Houthi forces have done in the Red Sea), or threatening penalties and sanctions for failing to comply, may in effect be tantamount to a blockade.

How to counter a blockade

It is not clear how other nations would respond to a Chinese invasion or blockade.

In recent years, China has attempted to project its naval power by establishing no-go zones in its neighbourhood, such as turning the South China Sea into its own fortified waters.

One way to oppose China, then, would be a counter-blockade. This would entail allied naval forces, likely led by the United States, closing the choke points, such as the Malacca Strait, on which Chinese seaborne trade with global markets depends.

However, counter-blockades are problematic, too. The impact on the world economy would be huge, as a blockade of the Malacca Strait, for example, could impact all trade between Asia and the rest of the world. China has also stockpiled domestic resources and expanded its land-based trade routes in recent years.

The best option, then, might be supporting Taiwan to survive a long blockade, forcing China to back down.

This means helping Taiwan become more resilient by increasing its food, fuel and medicine stockpiles, developing robust communication and cyber defences, and strengthening its port and energy infrastructure.

If the US built up its naval capacity in the Pacific, it could also use frigates to escort convoys of merchant ships to break a Chinese blockade, though the CSIS war games indicated this could come at a considerable cost of lives and ships – and increase the potential for all-out war.

The Conversation

Claudio Bozzi does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.

ref. China may not invade Taiwan, but rather blockade it. How would this work, and could it be effective? – https://theconversation.com/china-may-not-invade-taiwan-but-rather-blockade-it-how-would-this-work-and-could-it-be-effective-257731

What chaos at the US CDC could mean for the rest of the world

Source: The Conversation – Global Perspectives – By Michael Toole, Associate Principal Research Fellow, Burnet Institute

Ever since Robert F Kennedy (RFK) Jr was appointed United States Secretary of Health and Human Services, the Centers for Disease Control and Prevention (CDC) has been under pressure to abandon its traditional evidence-based approach to public health in America and across the world.

That pressure came to a head last week with the sacking of recently appointed CDC director Susan Monarez. According to her lawyers, the longtime government scientist, who had been in the role less than a month, was targeted after she refused to “rubber-stamp unscientific, reckless directives”.

Monarez will be replaced by Jim O’Neill, deputy director of the Department of Health and Human Services. Critics note he has no medical or scientific training.

On the same day as Monarez’s firing, three senior officials resigned. They included the CDC’s chief medical officer, and two others with leadership roles in areas including vaccines and emerging diseases.

I worked at the CDC between 1986 and 1995. Almost all of my work was with activities overseas.

While the CDC is a key institution overseeing and funding public health in the US, it’s also instrumental in global health. Consequently, turmoil at the CDC could have an impact not just in the US, but around the world.

Vaccine scepticism: a threat to public health

Soon after the inauguration of US President Donald Trump for the second time in January 2025, threats to American public health became clear. RFK Jr was confirmed as the Secretary of Health and Human Services in February, with authority over the CDC.

By April, 25% of CDC staff had been fired and its contract spending was cut by 35%. Cancelled CDC programs included those focused on the prevention of lead poisoning in children, environmental health, and sexually transmitted infections including HIV.

Notably, RFK Jr has a long history of vaccine scepticism.

In 2019–20, more than 5,700 people became infected when a measles outbreak ravaged the island nation of Samoa. Some 83 people died, most of them children.

In the lead up, a number of ads spread vaccine misinformation on Facebook, sowing doubt about safety of the measles vaccine. Some were found to have been funded by Children’s Health Defense, an organisation founded by RFK Jr.

RFK Jr’s department has dismissed and replaced the 17 expert members of the Advisory Committee on Immunization Practices with eight new people – a number of whom have reportedly expressed anti-vaccination views.

During RFK Jr’s tenure so far, his department has:

RFK Jr is arguably the most important figure overseeing health in the US. It’s difficult to overestimate the harm his actions will do to vaccine confidence and uptake in America and around the world.

A long history of international aid

While the CDC had long provided advice to the World Health Organization (WHO) on malaria control, the first major overseas initiative was as an active partner in the WHO’s successful global smallpox eradication program. Along with the Soviet Union, the CDC initially focused on West Africa in the 1960s and then India and Bangladesh in the 1970s.

The CDC’s first international emergency health response occurred during the Biafra conflict, which led to widespread famine in the Eastern part of Nigeria. In 1968, at the request of the International Committee of the Red Cross, the CDC mobilised staff to monitor nutrition and design programs to combat malnutrition.

The agency’s largest ever overseas intervention began in March 2014 when an Ebola outbreak occurred in Guinea, Sierra Leone and Liberia. By July 2015, the CDC had allocated 3,000 staff to Ebola, with 1,200 on the ground in West Africa, including neighbouring countries such as Nigeria and Senegal. CDC staff provided technical advice on strengthening laboratory diagnosis, contact tracing and surveillance.

Following the Ebola outbreak, the Global Health Security Agenda was established as a coordinated epidemic preparedness initiative with members from more than 60 countries, United Nations agencies and non-governmental organisations. The Obama administration funded US involvement generously with the CDC leading US contributions.

Threats to global health

The first sign of a US withdrawal from global health came soon after Trump’s inauguration when he signed executive orders cancelling US membership of the WHO and suspending all US foreign development assistance.

This led to the cancellation of large programs to prevent and treat HIV and AIDS, malaria, tuberculosis and hepatitis.

Soon after, CDC officials were ordered to cease all communications with the WHO, leading to CDC experts leaving global advisory committees, among other things.

The dismantling of the US Agency for International Development (USAID) has led to a loss of 83% of its programs and the cancellation of 5,200 contracts. This has stymied its ability to effectively deliver lifesaving aid, including in countries devastated by conflict and famine, such as Sudan. One study predicted the cuts in USAID funding could lead to 14 million extra deaths by 2030.

Budget and staff cuts have seriously reduced the CDC’s capacity to engage in global initiatives. For example, the Maternal and Child Health Branch was shut down and all 22 staff terminated. This branch helped low- and middle-income countries implement programs to prevent HIV in pregnant women and their babies.

The loss of financial resources and a large number of expert staff means the agency faces an uncertain future. Interference in its procedures to develop science-based health policies will gravely affect its ability to carry out its mandate both domestically and globally. The CDC has lost the trust of the American people and is no longer regarded as the preeminent public health agency in the world.

Governments, research institutes and health development agencies around the world must unite to decry this loss of global health expertise. Millions of lives depend on forceful action.

The Conversation

Michael Toole receives funding from the National Health and Medical Research Council. He worked for the US CDC between 1986 and 1995. The content of this article represents the views of the author and not those of the Burnet Institute.

ref. What chaos at the US CDC could mean for the rest of the world – https://theconversation.com/what-chaos-at-the-us-cdc-could-mean-for-the-rest-of-the-world-264188

80 years since the end of World War II, a dangerous legacy lingers in the Pacific

Source: The Conversation – Global Perspectives – By Stacey Pizzino, Lecturer, School of Public Health, The University of Queensland

Aerial view of Enewetak Atoll showing nuclear test craters. Gallo Images/Orbital Horizon/Copernicus Sentinel Data 2021

On September 2, 1945, the second world war ended when Japan officially surrendered. Today, on the 80th anniversary, the physical legacy of the conflict remains etched into land and sea.

Nowhere is this more evident than in the Pacific. There, fierce battles left behind sunken warships, aircraft and unexploded bombs. These remnants are not only historical artefacts but toxic time capsules.

They leak fuel, heavy metals and other hazardous substances into fragile ecosystems, threatening biodiversity and, potentially, human health.

This problem is a reminder of the enduring environmental harms of conflict. Toxic remnants of war can damage ecosystems and communities long after the fighting stops.

The Pacific as a dumping ground

World War II in the Pacific involved four years of conflict between Japan and Allied forces. The war began in the region in December 1941 when Japan attacked a United States naval base at Pearl Harbour, Hawaii.

The Pacific conflict included the Battle of the Coral Sea, the Battle of Midway and the Guadalcanal campaign in the Solomon Islands.

Pacific islands became staging grounds for battles. Weapons were stockpiled and hazardous material discarded. Ships and aircraft were sunk. When the war ended, much of this material was simply left behind.

Among the remains are an estimated 3,800 wrecks still lying on the Pacific Ocean floor.

An environmental hazard

As remnants of war degrade, they often leach toxic pollutants into nearby waters and soils. These can build up in marine life, enter the food chain and pose serious risks to both biodiversity.

At Palau, a WWII Japanese ship sank in Koror Harbour and became known as the Helmet Wreck. It contains Japanese depth charges leaking acid into surrounding waters.

Researchers have shown the long-term environmental impacts in the Baltic Sea of unexploded WWII ordnance – bombs, shells and grenades that failed to detonate. An estimated 3000kg of dissolved ammunition chemicals have been found.

Coral reefs and mangroves, which are vital for coastal protection, are especially vulnerable to both chemical exposure and physical damage.

For example, researchers examined the effects off Puerto Rico of unexploded ordnance. They found nearby sea animals contained potentially toxic compounds leaking from the ordnance, which meant the substances had entered the food web.

Human communities on high alert

Unexploded ordnance continues to endanger communities. Just last year, for example, more than 200 bombs were found buried beneath a school in the Solomon Islands.

In places such as Palau, Papua New Guinea and the Solomon Islands, these dangers are unearthed regularly. They can be found by farmers working their land, children playing or fisherman working.

Buried bombs, sunken ships and downed aircraft often contain fuel and heavy metals. This includes lead and cadmium which can interfere with the body’s hormone system and cause serious health issues.

Research into the human health impacts of war remains is limited – especially in the Pacific. But existing studies suggest exposure is linked to serious consequences.

For example, parental exposure to wartime contaminants has been linked to birth defects in Gaza and Vietnam.

And a study of Britsh Army ammunition technicians released earlier this year found significantly higher rates of bladder cancer than the general population. This suggests occupational exposure to explosive compounds may pose long-term health risks.

Climate change is increasing the risk

As Earth’s climate warms, extreme weather events are worsening and seas are rising. This is exacerbating the dangers posed by wartime remnants.

For example Cyclone Pam, in March 2015, exposed unexploded WWII ordnance in Kiribati and Tuvalu. Further investigations revealed remnants including high explosive projectiles, mortars and 5,300 rounds of ammunition.

In 2020, a visiting fisherman found an unexploded bomb near Lord Howe Island. Then-Environment Minister Sussan Ley suggested the device may have been shifted by a cyclone or ocean currents.

Similarly, floods and landslides can move these hazards over significant distances, increasing uncertainty around their locations and complicating clearance efforts.

Rising sea levels are threatening to breach one of the Pacific’s most toxic legacies – the Runit Dome in the Marshall Islands. This concrete structure was built in the late 1970s to contain radioactive waste from US nuclear testing decades earlier.

Research shows extreme storms could increase radioactive sediments in the area to up to 84 times higher than normal. There are also concerns cracks in the dome’s surface could lead to contamination of surrounding waters.

Five people in yellow protective clothing stand near the water.
In this 1978 photo from Runit Island, military personnel in protective clothing watch as concrete and soil is used to cover up a crater left by the US after it conducted nuclear tests decades earlier.
Department of Defense/US Army/FPG/Archive Photos/Getty Images

Reflecting on war’s toxic legacy

Despite the risks to people and health in the Pacific, remediation has been slow. The 80th anniversary of WWII offers an opportunity to reflect on the toxic legacy of war – and to act.

The scale of the problem demands coordinated, well-funded action. The work should not just remove dangerous materials, but restore damaged ecosystems and monitor long-term health impacts.

Some support has been offered. It includes Operation Render Safe, a program to remove war remnants led by the Australian Defence Force. But more is needed.

Regional partners – including Australia, New Zealand, Japan and the United States – have a chance to lead. This means investing in environmental cleanup, supporting affected communities and acknowledging historical responsibility.

It also means listening to Pacific voices, who have long called for greater attention to the war’s toxic legacy. Their knowledge, resilience and lived experience must be central to any response.


The authors acknowledge Nixon Panda for his contribution to this article.

The Conversation

The authors do not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and have disclosed no relevant affiliations beyond their academic appointment.

ref. 80 years since the end of World War II, a dangerous legacy lingers in the Pacific – https://theconversation.com/80-years-since-the-end-of-world-war-ii-a-dangerous-legacy-lingers-in-the-pacific-264127

How to save global cancer research from Trump’s cuts

Source: The Conversation – UK – By Michael Head, Senior Research Fellow in Global Health, University of Southampton

ImagePixel/Shutterstock.com

Cancer kills one in five people globally. Yet, except for a one-off increase in 2021, the flow of money for cancer research has trended downward every year since 2016.

Our new analysis of more than 100,000 public and philanthropic grants reveals where research funding is being allocated. There are very likely to be reductions in funding from the US under the Trump government. So it’s important to understand how other groups of countries, such as the Commonwealth, can address this shortfall.

The Commonwealth is a network of 56 nations. Membership includes high-income countries such as the UK, Canada and Australia, and lower-income members in Africa and the Caribbean. Together, its members account for over 14% of cases of common cancers globally in 2020 – a share projected to rise to 17% by 2050.

Survival rates vary dramatically, from under 5% five-year survival in some lower-income countries to 60% in wealthier countries. Understanding how research funding flows within this diverse group offers a roadmap for fairer investment and opportunities for international collaboration. This can also help address the likely funding gaps from the US.

As a part of the Lancet Oncology Commission for Cancer in the Commonwealth, we and partners across several institutions took the most comprehensive look to date at global cancer research investment (2016–23). We mapped over 107,955 awards worth US$51.4 billion (£38.1 billion), categorising each project by cancer type, type of research and funder. We then used global and Commonwealth-wide network maps to reveal which countries were central to awarded grants, publications, clinical trials and patents, and which countries remained peripheral.

Our analysis showed that laboratory studies received 76% of funding (US$39 billion), while clinical trials drew just 7.3% (US$3.7 billion).

Breast cancer accounted for 10.3% of the funds (US$5.3 billion), and blood cancers accounted for 9% (US$4.7 billion). Despite their central role in treatment, surgery research was the focus of only 1.7% (US$0.8 billion) and radiotherapy 3.1% (US$1.6 billion).

Lower-income countries received less than 0.1% of total grants, highlighting a stark mismatch between cancer burden and research capacity.

Funders’ heavy focus on laboratory science potentially starves the late-stage trials and implementation research that translate discoveries into patient care.

The small amount of investment in surgery and radiotherapy research risks slowing advances in methods that already save lives today. Equally, the near-absence of funding led by lower-income countries perpetuates a cycle where countries with the greatest projected rise in cancer cases have the least capacity to respond.

Within the Commonwealth, the UK, Australia and Canada dominate both in terms of providing and receiving grant funding. These three countries serve as hubs for collaboration – linking lower-income countries to the US and EU.

In contrast, collaboration among lower-income Commonwealth countries on developing new drugs and technology remains weak, suggesting untapped potential in turning lab discoveries into new treatments and products across a wider breadth of countries.

With an unpredictable president in the White House, it’s vital to understand how other groups of countries can address the likely gaps. To this end, we illustrated below the effect of a potential funding cut from the US, and then measured the effort required for each group of countries to compensate for a hypothetical 50% cut of the US funding.

Global collaboration networks before (left) and after (middle) the US funding cut, and how each group of countries can compensate for the cut (right).
CC BY-NC-SA

Cutting US funding will significantly weaken international collaboration ties, which makes sharing ideas and skills harder. Yet, as shown in the table below, each group has sufficient stock of domestic grants where turning only a small proportion into cross-border grants is enough to restore the collaboration level. That is, the EU to raise its share from 4.18% to 4.48%, non-US G7 countries from 1.11% to 1.20%, the rest of the world from 1.63% to 1.89%, the Commonwealth from 0.66% to 0.69%, and Brics (Brazil, Russia, India, China and South Africa) from 0.49% to 0.99%.

Group domestic international int_pct int_pct_target compensation
EU 5224 228 4.18% 4.48% 16
BRICS 4198 20 0.49% 0.99% 21
G7_no_US 18720 210 1.11% 1.20% 17
CW 7028 47 0.66% 0.96% 21
ROW 8114 135 1.63% 1.89% 21
Total grants per group and the extra cross-border grants needed to rebuild collaboration levels. Column ‘domestic’ is the number of grants carried out entirely within one country. Column ‘international’ (‘int_pct’) is the number (and percentage) of grants involving partners in more than one country. Column ‘int_pct_target’ is the share of international grants each group needs to reach the same level of research-link strength as before the funding cut. Column ‘compensation’ is how many additional cross-border grants each group must add to get back to the original level of research-link strength.

The numbers tell a straightforward story. When the US cuts cancer research funding, it breaks connections among researchers worldwide. This makes it harder for scientists to share discoveries and learn from each other – ultimately hurting cancer patients everywhere.

But other countries can step up to fill this gap. The table shows that each group of countries already funds plenty of domestic research. They just need to redirect a small portion of these existing grants to include international partners. This would restore the global research network to its previous strength.

This is an opportunity for governments to work together and take the lead on cancer research when the US steps back.

Four practical steps could make this happen.

  1. Match funding to where cancer hits hardest. Review current grants to ensure money goes to the deadliest cancers and the countries with the worst survival rates.
  2. Create research hubs in poorer countries. Build centres of excellence in lower-income Commonwealth countries that can train researchers, share data and run clinical trials.
  3. Fund surgery and radiotherapy research. These treatments save lives today, but get barely any research money. They deserve dedicated funding streams.
  4. Help researchers turn discoveries into treatments. Create programmes that help scientists in all Commonwealth countries – not just wealthy ones – patent their discoveries and develop them into actual medicines.

Looking ahead

Cancer kills nearly 10 million people each year, with over 20 million new cases diagnosed. By 2050, deaths are estimated to reach 18 million. The numbers are getting worse, not better.

The Commonwealth’s wealthy countries – the UK, Canada and Australia – could serve as bridges, connecting researchers across rich and poor nations. Done right, this could reshape how the world fights cancer, ensuring no country gets left behind simply because they lack resources.

The Conversation

Michael Head has previously received funding from the Bill & Melinda Gates Foundation, Research England and the UK Department for International Development, and currently receives funding from the UK Medical Research Foundation, and UK Research and Innovation

Markus Brede receives funding from UK Research and Innovation and has previously received funding from the Royal Society and the Alan Turing Institute.

Anbang Du does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.

ref. How to save global cancer research from Trump’s cuts – https://theconversation.com/how-to-save-global-cancer-research-from-trumps-cuts-258642

Guía para conocer los microorganismos que dan vida a los suelos y aseguran el futuro agrícola

Source: The Conversation – (in Spanish) – By Mariano Angel Valdivia Dávila, Ciencias agrícolas y biotecnología, Universidad de Guadalajara

Microorganismos cultivados en una muestra de suelo en el laboratorio. Sinhyu Photographer/Shutterstock

El suelo es el medio natural compuesto por minerales, materia orgánica, aire y agua. Provee de elemento hídrico, soporte y nutrientes a las plantas. Gracias a él, los humanos obtenemos un 98,8 % del total de las calorías que consumimos.

También sirve como hogar para una gran cantidad de seres vivos que no se ven a simple vista, entre los que destacan bacterias, hongos, virus, arqueas, protozoos, algas y nematodos. Los más estudiados debido a las funciones que realizan son las bacterias, los hongos y, en menor medida, las arqueas.

Estos minúsculos habitantes determinan el estado microbiológico de los suelos y les aportan múltiples beneficios. Su ausencia o escasez implica menos energía, menos agua y menos vida, lo que da sentido al auge de las experiencias agroregenerativas. Unas prácticas que buscan devolverle al suelo condiciones vitales para garantizar un medio agrario más ecológico y económicamente viable.

Los microorganismos se encargan de descomponer la materia orgánica y participan en el reciclaje y fijación de algunos nutrientes (nitrógeno, fósforo y potasio, entre otros).

Otra de sus funciones consiste en agrupar el suelo en terrones conocidos como agregados, que mejoran la retención de agua y la aireación. Además, promueven el crecimiento de cultivos y los protegen del ataque de plagas y enfermedades.

De la siembra y conteo a la secuenciación del ADN microbiano

El estudio de los microorganismos del suelo nace a mediados del siglo XIX. La siembra y conteo en placa, método microbiológico para estimar el número de microorganismos viables en una muestra, es una de las primeras técnicas y la más utilizada hasta la actualidad. No obstante, solo se han podido cultivar de este modo alrededor del 50 % de los microorganismos existentes.

En la década de los 70 del siglo XX se desarrolló una metodología que cuantifica la respiración del suelo. Esta técnica mide el dióxido de carbono que liberan los microorganismos como resultado de la degradación de materia orgánica. A partir de los estudios derivados, fueron sentadas las bases de lo que más tarde se ha conocido como “ecología microbiana”.

A la par, se desarrolló otra metodología que registra la actividad enzimática. Sirve como indicador de la presencia de microorganismos porque permite contabilizar los tipos de enzimas liberadas como consecuencia de la degradación de los materiales orgánicos.

Los avances más significativos surgen en los años 90 del siglo pasado con el desarrollo de las metodologías basadas en la extracción de ADN microbiano y su posterior secuenciación e identificación. Gracias a ellas, resulta posible identificar los microorganismos directamente del ambiente natural y conocer sus aportes al entorno.

Un tercio de los suelos sufren degradación

Según datos de la Organización de las Naciones Unidas para la Alimentación y la Agricultura (FAO), al menos el 33 % de los suelos de todo el planeta presentan algún nivel de degradación, ya sea leve, moderado o grave.

La principal razón de esta degradación tiene que ver con el hombre y su afán para producir más y mejores alimentos, que den respuesta a la demanda de una población en aumento constante.

Concretamente, la agroindustria impacta por el manejo del suelo, el uso excesivo de productos químicos (fertilizantes, herbicidas, insecticidas etc.) y la tendencia a favorecer la siembra de un solo tipo de cultivo (monocultivos).

Las malas prácticas han ocasionado diferentes afectaciones: pérdida de materia orgánica, erosión, suelos más salinos, cambios en el pH y contaminación de fuentes de agua. Estas afectaciones disminuyen el contenido de microorganismos del suelo y, a su vez, provocan una disminución en la fertilidad. El resultado es la reducción paulatina del rendimiento de cultivos, la degradación del suelo y el peligro para la seguridad alimentaria.




Leer más:
Cómo afectan la agricultura y la ganadería a la biodiversidad del suelo


Textura, pH y temperatura

Dichas afectaciones modifican las características físicas y químicas del suelo que interactúan con los microorganismos, moldeando el crecimiento o disminución de especies. Estudios demuestran que la textura, el pH, la temperatura y los nutrientes son los principales factores que inciden en la presencia de microorganismos en el suelo.

La textura condiciona el crecimiento de microorganismos. Un suelo poco poroso reduce la cantidad de agua que puede retener y el oxígeno disponible. Además, la cantidad de nutrientes aumenta o disminuye según su composición mineral.

Otro elemento que limita el crecimiento de microorganismos es el pH o potencial de hidrógeno, que mide la acidez o alcalinidad. El valor del pH en el suelo oscila entre 3,5 (muy ácido) a 9,5 (muy alcalino). Los suelos muy ácidos (<5,5) tienden a presentar cantidades elevadas y tóxicas de aluminio y manganeso. Los suelos muy alcalinos (>8,5) pueden dispersarse.

El pH del suelo depende de la composición mineral, el tiempo de formación y la cantidad de lluvia. La modificación del pH, aunque sea mínima, provoca la pérdida de microorganismos debido a la adaptación al nuevo factor.

Por otro lado, el cambio climático provocado por la actividad humana ha modificado la temperatura del planeta. Un cambio que afecta al crecimiento de microorganismos y a la fertilidad de los suelos.

Microorganismos, humus y simbiosis

En el suelo, los microorganismos son los encargados de descomponer la materia orgánica, esparciendo sustancias conocidas como enzimas.

Este proceso genera una tierra negra llamada humus que mejora la textura, la retención de agua y la nutrición de las plantas. También hace posible el ciclo de nutrientes (carbono, nitrógeno, fósforo, potasio), que desencadena la transformación de la materia y la consecuente fertilización del suelo.

Las plantas y los microorganismos conviven cercanamente y comparten beneficios. Las plantas liberan sustancias por la raíz (exudados) que atraen microorganismos para realizar una unión benéfica llamada simbiosis. En esta unión, las plantas le dan alimento al microorganismo (azúcares) y los microorganismos acercan agua y nutrientes a la planta, incluso la protegen de plagas y enfermedades.

¿Cómo afecta la disminución de microorganismos en el suelo?

La pérdida de microorganismos provoca deterioro en los suelos, lo que afecta negativamente al rendimiento de cultivos.

Existe el riesgo de un aumento de la incidencia de plagas y enfermedades en los cultivos debido a la falta de microorganismos benéficos, así como por la ausencia de sus asociaciones simbióticas. Es el caso de aquellas que hacen solubles algunos nutrientes (micorrizas) o facilitan la descomposición (saprofitos), por mencionar algunas.

Estas situaciones limitan también el secuestro de carbono al disminuir la actividad biológica. Un hecho que implica mayor contaminación en muchos ambientes naturales, ya sean suelo, agua o aire.




Leer más:
¿Por qué hablamos de cuidar la salud del suelo?


¿Quiénes y de qué manera están actuando?

Organizaciones internaciones como la FAO y la Convención Marco de las Naciones Unidas sobre el Cambio Climático, a través de las denominadas Conferencias de las Partes, han propuesto acciones para revertir la degradación del suelo y favorecer el aumento de los microorganismos.

Por su parte el Departamento de Agricultura de los Estados Unidos (USDA) promueve a través de diversos programas la sustentabilidad agrícola que involucra el cuidado del suelo.

Otro tanto realizan asociaciones sin fines de lucro, como Kiss the Ground, una iniciativa que coloca el cuidado del suelo y la importancia de los microorganismos en el centro de la estrategia para revertir el cambio climático y garantizar la seguridad alimentaria. Su mensaje se está dando a conocer a través de un documental narrado por el conocido actor y activista Woody Harrelson.

Dentro de las acciones que promueven estas instituciones, destacan la agricultura con labranza mínima o cero labranza, que permite el desarrollo de microorganismos. También gana adeptos la agricultura de asociación, que consiste en una vuelta a los sistemas de agricultura tradicional, como la milpa mexicana, que producen más de un cultivo a la vez en el mismo suelo. Esta práctica concentra diversidad de plantas y un mayor contenido de microorganismos, lo que se traduce en una menor incidencia de plagas.

La agricultura orgánica, que recurre al uso de fertilizantes orgánicos como la composta y de productos biológicos a partir de microorganismos, representa otra opción.

Faltan más conocimientos y recursos para entender los procesos y financiar las nuevas tecnologías que permitan desarrollar estas acciones con la máxima eficacia. Pero la divulgación de la importancia del suelo y sus microorganismos contribuye sin duda a avanzar hacia un mundo agrario más seguro y sostenible.

The Conversation

Mariano Angel Valdivia Dávila 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. Guía para conocer los microorganismos que dan vida a los suelos y aseguran el futuro agrícola – https://theconversation.com/guia-para-conocer-los-microorganismos-que-dan-vida-a-los-suelos-y-aseguran-el-futuro-agricola-262416

Avispa asiática: por qué la captura masiva con trampas debe parar

Source: The Conversation – (in Spanish) – By Yaiza R. Lueje, Ayudante de investigación en gestión de especies exóticas invasoras e infraestructuras verdes, Universidade da Coruña

Abejorros del género _Bombus_ recogidos en una trampa para avispas asiáticas. Los autores, CC BY-SA

Las especies exóticas invasoras suponen un enorme problema ambiental, en muchos casos con efectos inmediatos y muy potentes. Este fenómeno obliga a todos los actores implicados, como las administraciones competentes, a elaborar planes de respuesta que no siempre son efectivos por la falta de base científica en su diseño. Sin embargo, cuando estas especies afectan a sectores productivos clave, al abastecimiento de bienes esenciales o a la salud humana, esta necesidad de respuesta se vuelve más urgente.

El caso de la avispa asiática (Vespa velutina) es muy ilustrativo por la rapidez de su expansión, su impacto sobre el sector agrícola y el riesgo potencial que sus picaduras suponen para la población. En apenas 10 años, la especie colonizó gran parte de la Europa atlántica, incluido el norte y oeste de la península ibérica.

Esta avispa es muy conocida por predar sobre las abejas melíferas, provocando grandes daños en la apicultura, y por consumir diferentes alimentos, como productos hortofrutícolas. Además, puede ser peligrosa para las personas porque sus picaduras son capaces causar reacciones alérgicas graves, lo que genera mucha preocupación en la población.

Avispa asiática sobre madera
Individuo de avispa asiática.
Siga/Wikimedia Commons, CC BY-SA

Un método que elimina avispas, pero también otros insectos

La respuesta de la población, y en especial de sectores afectados como la apicultura, ha sido activa y homogénea en regiones como Galicia o Asturias, centrada en técnicas de trampeo para la eliminación de adultos. Este método de control de plagas utiliza trampas para atraer a estos insectos con un cebo, generalmente líquido, atraparlos mediante un sistema de embudo o barrera e impedir su escape.

También se han estudiado otros sistemas de control como arpas eléctricas para la protección de colmenares o mallas para la protección de viñedos. Sin embargo, estos sistemas no pretenden reducir las poblaciones de avispa, sino únicamente proteger los recursos de sus ataques.

La generalización del uso de trampas para la captura de adultos puede verse en cualquier rincón de la Galicia costera, con trampas caseras o comerciales colocadas en todo tipo de espacios, públicos y privados, consentidos y fomentados por la administración.

Tanto la Xunta de Galicia como distintas administraciones locales han promovido el uso de trampas caseras de cebo líquido por parte de la población, publicando instrucciones para su construcción e incluso realizando campañas de trampeo propias. Sin embargo, ninguna trampa disponible hasta el momento actual es totalmente selectiva. El número de otros insectos capturados por todas las trampas instaladas, que en muchos modelos se ha demostrado que puede alcanzar porcentajes superiores al 90 %, es totalmente desconocido.

Una botella convertida en trampa para avispas en un viñedo
Trampa para avispas colocada en un viñedo.
Los autores, CC BY-SA

Las trampas no reducen los daños en viñedos

En nuestra reciente investigación, publicada en Pest Management Science, hemos analizado cómo afecta la avispa asiática a la producción de uva en viñedos gallegos. Encontramos gran variabilidad en los daños según la zona y la localización de los viñedos y, además, descubrimos que no están relacionados con el contenido de azúcar en las uvas. Las avispas tienen preferencia por alimentos dulces, por lo que podría esperarse que a mayor contenido de azúcar en las uvas del viñedo las avispas provocasen más daño en el mismo, pero en nuestro trabajo no observamos dicha relación.

Al estudiar el impacto de distintos tipos de trampas de uso común a lo largo del año, vimos que el porcentaje de avispas del total de insectos capturados varía mucho y también cambian los resultados entre los diferentes modelos de trampas. Sin embargo, estas diferencias no se relacionan con el grado de afección sobre los viñedos.

Además, usar diferentes densidades de trampas durante la época en la que ocurren los daños en las uvas no sirve para reducirlos. No hay diferencias significativas en el daño total a las uvas entre zonas con y sin trampas, incluso en altas densidades.

La cantidad y diversidad de capturas de otros insectos, aunque variables a lo largo del año (desde aproximadamente un 95 % de las capturas totales en primavera hasta un 3 % en las últimas semanas previas a la vendimia), demuestran que el posible impacto en sus poblaciones puede ser muy alto. Además, el escaso conocimiento sobre la biología y ecología de la mayor parte de grupos impide calibrar el impacto real de esas capturas.

Sin embargo, se ha observado que el trampeo captura grandes cantidades de insectos polinizadores. Otros investigadores han descrito un declive generalizado de este grupo tan importante de insectos, aunque se discute la magnitud y las causas del fenómeno.

Paremos el trampeo masivo

El principio de precaución establece que, en lo posible, debe evitarse cualquier medida con un impacto negativo potencial si no existe la suficiente evidencia científica que demuestre su validez. En el mismo sentido, si esa medida no se ha demostrado eficaz, no debería emplearse hasta demostrar su utilidad o seleccionar una nueva.

El trampeo de avispa asiática no cumple ninguna de las dos premisas. Captura otras especies de insectos, generando un posible impacto negativo, y ningún estudio científico publicado ha podido demostrar un efecto positivo sobre la protección de los recursos o las personas. El trampeo, promovido por la administración, puede dar una falsa idea de efectividad por las capturas generadas, pero eso no implica que cumpla el objetivo de evitar los impactos de la especie invasora.

Por ello, conminamos a la administración, al sector agrícola y a la población a observar la evidencia generada y reconsiderar su postura en relación a esta técnica de eliminación de insectos. Los problemas ambientales son complejos y raramente pueden solventarse con soluciones rápidas y fáciles.

The Conversation

Yaiza R. Lueje recibe fondos del proyecto “Viño e froita – Cooperacion Leader’ (program LEADER Galicia 2014 – 2020)”.

Jaime Fagúndez Díaz y María J. Servia no reciben salarios, ni ejercen labores de consultoría, ni poseen acciones, ni reciben financiación de ninguna compañía u organización que pueda obtener beneficio de este artículo, y han declarado carecer de vínculos relevantes más allá del puesto académico citado.

ref. Avispa asiática: por qué la captura masiva con trampas debe parar – https://theconversation.com/avispa-asiatica-por-que-la-captura-masiva-con-trampas-debe-parar-261190

Macrófagos: el decisivo papel de las ‘células tragonas’ del sistema inmunitario en nuestra salud

Source: The Conversation – (in Spanish) – By Antonio J. Ruiz Alcaraz, Profesor de Inmunología de la Universidad de Murcia e investigador del Grupo de Inmunidad Innata del IMIB, Universidad de Murcia

El sistema inmunitario humano es una red compleja y altamente especializada de moléculas, células, tejidos y órganos que actúan coordinadamente para proteger al organismo frente a agentes patógenos. Dentro de este sistema, los macrófagos llevan a cabo un papel fundamental como centinelas y ejecutores de la llamada respuesta inmunitaria innata.

Estas células no solo participan en la defensa inmediata contra infecciones, sino que también están involucradas en procesos como la reparación de los tejidos, la homeostasis o equilibrio corporal y la modulación de las respuestas inflamatorias. Sin embargo, su participación prolongada o descontrolada puede contribuir al desarrollo y perpetuación de enfermedades crónicas inflamatorias.

¿De dónde vienen los macrófagos?

Los macrófagos tienen un doble origen. Tradicionalmente se pensaba que todos procedían de los monocitos, un tipo de leucocito o célula blanca que circula por la sangre. Los monocitos se originan en el interior de los huesos, en la médula ósea y, una vez reclutados hacia tejidos específicos en respuesta a señales inflamatorias o fisiológicas, se diferencian en macrófagos residentes en los tejidos. Este proceso es dinámico y permite al organismo responder de forma flexible a múltiples desafíos.

Sin embargo, investigaciones más recientes han revelado que muchos macrófagos tisulares residentes –es decir, aquellos que permanecen en tejidos de forma estable– no derivan exclusivamente de monocitos adultos. Algunos tienen su origen en etapas embrionarias tempranas, especialmente a partir del saco vitelino y el hígado fetal, colonizando diversos tejidos incluso antes del nacimiento.

Estos macrófagos embriogénicos pueden autorrenovarse localmente sin necesidad de un aporte constante de monocitos circulantes en la sangre y procedentes de la médula ósea.

Por sus nombres les conoceréis

Los macrófagos están distribuidos por todo el organismo y adoptan características especializadas según el tejido en el que residen. Esta plasticidad funcional se debe a la influencia del microambiente local, lo que les permite adaptarse a las necesidades específicas de cada órgano y cumplir funciones concretas.

Microfotografías de células de microglía.
Microfotografías de células de microglía.
Yang TD, Park J-S, Choi Y, Choi W, Ko T-W, Lee KJ/Wikimedia Commons, CC BY

Por ejemplo, en el hígado se conocen como células de Kupffer y desempeñan un papel clave en la eliminación de sustancias tóxicas y microorganismos procedentes del tracto digestivo. En el sistema nervioso central se les denomina microglía y están implicados tanto en la defensa frente a infecciones como en el mantenimiento de la homeostasis o salud neuronal.

Otros ejemplos incluyen los macrófagos alveolares de los pulmones, que eliminan partículas inhaladas a modo de basureros, y los osteoclastos, que participan en el remodelado óseo como escultores de los huesos.

Células multitarea

Las múltiples funciones de los macrófagos abarcan tanto aspectos inmunológicos como no inmunológicos. En primer lugar, son expertos en fagocitosis, el proceso mediante el cual engullen y destruyen partículas extrañas, células muertas y restos celulares. Esta capacidad los convierte en una primera línea de defensa contra infecciones bacterianas, virales y fúngicas.

Pero además, estas células resultan esenciales en la presentación de antígenos. Tras fagocitar un patógeno, procesan sus componentes y los exponen en su superficie mediante moléculas del complejo mayor de histocompatibilidad (MHC). Esto permite activar a los linfocitos T, otras células clave en la función del sistema inmunitario, y poner en marcha la respuesta inmunitaria adaptativa. Esta, más específica y duradera, puede guardar una memoria de los patógenos concretos que los han activado.

Otra función crucial de los macrófagos es la secreción de citoquinas y factores de crecimiento. Se trata de moléculas solubles que regulan la inflamación, atraen otras células inmunitarias y favorecen la reparación de tejidos.

Dependiendo del tipo de señales que reciban, los macrófagos pueden diferenciarse como M1, asociados a respuestas proinflamatorias y microbicidas, o M2, vinculados a procesos antiinflamatorios, resolución de la inflamación y regeneración y reparación de tejidos.

Su papel en enfermedades inflamatorias crónicas

Ya hemos visto que los macrófagos son esenciales para la defensa y el equilibrio fisiológico, pero su activación prolongada o disfuncional puede tener consecuencias perjudiciales. De hecho, están estrechamente implicados en diversas enfermedades inflamatorias crónicas como la artritis reumatoide, la aterosclerosis, la diabetes tipo 2 y diversas dolencias neurodegenerativas como el alzhéimer.

En estas patologías, los macrófagos pueden mantener un estado de activación persistente, secretando citoquinas proinflamatorias como el factor de necrosis tumoral alfa (TNF-α), la interleucina-1 beta (IL-1β) y la interleucina-6 (IL-6). Estas moléculas actúan como sustancias mensajeras que contribuyen a mantener un entorno inflamatorio sostenido. Lejos de resolver el daño, este entorno promueve la destrucción del tejido, la fibrosis (cicatrización) y la progresión de la enfermedad.

Por ejemplo, en la aterosclerosis, los macrófagos fagocitan lípidos oxidados y se convierten en células espumosas que se acumulan en las paredes arteriales, formando placas que pueden obstruir el flujo sanguíneo. En la diabetes tipo 2, la inflamación crónica del tejido adiposo, mediada por macrófagos M1, se asocia con resistencia a la insulina. Y en el alzhéimer, la microglía activada (macrófagos del sistema nervioso) puede contribuir a la neuroinflamación y la degeneración neuronal al responder de forma inapropiada a la acumulación de placas de beta-amiloide.

En síntesis, los macrófagos son componentes clave del sistema inmunitario humano, actores centrales en la defensa del organismo, con una notable versatilidad funcional y adaptativa. No obstante, cuando su actividad se descontrola, pueden contribuir significativamente a enfermedades inflamatorias crónicas de gran impacto en la salud global. Comprender en profundidad su biología y su papel en las enfermedades resulta esencial para el desarrollo de nuevas estrategias terapéuticas dirigidas a modular su actividad y restaurar el equilibrio inmunológico.

The Conversation

Antonio J. Ruiz Alcaraz 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. Macrófagos: el decisivo papel de las ‘células tragonas’ del sistema inmunitario en nuestra salud – https://theconversation.com/macrofagos-el-decisivo-papel-de-las-celulas-tragonas-del-sistema-inmunitario-en-nuestra-salud-261694