fbpx
Connect with us

The Conversation

Could dinosaurs still exist somewhere in the world? A paleontologist explains

Published

on

theconversation.com – Hans Sues, Senior Research Geologist and Curator of Vertebrate Paleontology, Smithsonian Institution – 2024-08-12 07:22:41
The extinction event that killed the dinosaurs, 66 million years ago.
Mark Stevenson/UIG via Getty Images

Hans Sues, Smithsonian Institution

Curious Kids is a for of all ages. If you have a question you’d like an expert to answer, send it to curiouskidsus@theconversation.com.


Do dinosaurs still exist in some parts of the world ? โ€“ Ruben M., age 5


Did all dinosaurs become extinct, killed when an asteroid hit the Earth 66 million years ago? Or could a few of them, somehow, have survived that mass extinction event โ€“ with their descendants living even today?

It is exciting to imagine that gigantic dinosaurs are still rumbling and lumbering around in some remote part of the world. But no evidence of this exists. There are no cousins of Tyrannosaurus rex stomping through the vast woods of Siberia, no Apatosaurus ambling through the Congo rainforest.

Advertisement

As a paleontologist, I have spent much of my life studying ancient animals, particularly dinosaurs. But I have seen only fossils of these creatures, nothing living โ€“ with one exception. One group of dinosaurs is still around. To find them, just go outside and look up.

An armored dinosaur with body spikes trudges through a primeval forest.
Ankylosaurus was a plant-eating dinosaur with body armor and a tail club that could kill any attacker.
Daniel Eskridge/iStock via Getty Images Plus

The killer asteroid

In 1977, American geologist Walter Alvarez was working in the Apennine mountains in Italy. There, he found a thin layer of clay with an unusual amount of a metal called iridium in it. The clay was in between rocks from the Cretaceous and Paleogene periods and dates from the time the dinosaurs disappeared.

Iridium is rare on Earth but more common in some meteorites. Working with his father, Luis, who was a Nobel-Prize-winning physicist, Walter Alvarez developed the theory that a giant rock โ€“ an asteroid โ€“ collided with Earth 66 million years ago. This impact left iridium traces around the world and triggered the unimaginable disaster that killed the dinosaurs and countless other species of animals and plants on and in the sea.

At first, many scientists rejected the theory. But then, in 1991, geologists discovered a huge crater buried under the sea floor off the Yucatรกn Peninsula of Mexico. This spot was where an asteroid, about 6 miles (10 kilometers) across, crashed into our planet 66 million years ago.

The collision was so powerful it sent trillions of tons of dust and molten rock into the sky. Many pieces of molten rock fell back to Earth, causing huge wildfires everywhere. A thick blanket of dust in the atmosphere blocked most sunlight, leading to freezing temperatures worldwide. Earth turned into a cold, desolate place for many years, even centuries.

Advertisement

The loss of sunlight killed many plants. With no food available for them, big plant-eating dinosaurs like Triceratops quickly went extinct. That left big predators like Tyrannosaurus rex without prey animals to eat, so they died, too.

But smaller animals like mammals, lizards and turtles could adapt. They could hide in burrows and on a wide variety of foods. Fish lived in rivers and lakes and were protected by their watery homes. And surviving with them: birds, the only remaining dinosaurs.

Against a white background, a bird-like dinosaur, with feathers, sharp claws and a long tail, stands upright.
The adult Deinonychus weighed up to 220 pounds (100 kilograms).
SCIEPRO/Science Photo library via Getty Images

The bird connection

Fast-forward about 66 million years: Scientists noticed in the 19th century how the skeletons of modern birds and fossilized dinosaurs were alike in many ways. The similarities in the legs and feet were especially striking. However, most scientists then thought dinosaurs and birds were too different to be closely related.

Then, in 1964, dinosaur expert John Ostrom discovered fossils of the dinosaur Deinonychus. It had a mouth full of sharp teeth with serrated edges like steak knives, long slender hands with three fingers ending with large, curved claws, and a huge claw on the second toe of each . A fast hunter that did not fit the traditional ideas about dinosaurs as slow and not very active, Deinonychus lived in North America during the Cretaceous period, about 110 million years ago.

For another research project in the early 1970s, Ostrom examined the earliest known bird, Archaeopteryx, which lived 150 million years ago in what is now Germany. It had feathered wings and a wishbone, along with reptilelike traits, jaws with sharp teeth, hands with three fingers each, and a long tail.

Advertisement

Comparing this ancient bird with Deinonychus, Ostrom realized their skeletons shared many special features. For example, both had unusually long arms and hands, a very flexible wrist, hollow bones and an S-shaped neck.

Based on these and many other similarities, Ostrom showed that birds descended from small, predatory, birdlike dinosaurs.

Against a white background stands a bird-like dinosaur, with multicolored wings and an open mouth displaying sharp, razorlike teeth.
With sharp teeth and a long, bony tail, Archaeopteryx is a link to dinosaurs and modern-day birds.
Leonello Calvetti/Science Photo Library via Getty Images

In the past three decades, paleontologists have discovered many skeletons of ancient birds and birdlike dinosaurs in Jurassic and Cretaceous rocks in China. Surprisingly, the birdlike dinosaurs, including close relatives of Deinonychus, were covered in feathers, just like the birds living with them. Paleontologists now agree that many if not all dinosaurs maintained constant high body temperatures, just like birds and mammals do today. Feathers kept them warm.

Birdlike dinosaurs did not make it through the extinction event 66 million years ago โ€“ but some of the early birds who had lived alongside them did. And they evolved into the birds alive today.

Think of that: to see a dinosaur, all you need do is glance skyward. And as someone who has studied dinosaurs for a long time, I’m happy to know I share the world with dinosaurs.

Advertisement

Hello, curious kids! Do you have a question you’d like an expert to answer? Ask an adult to send your question to CuriousKidsUS@theconversation.com. Please tell us your name, age and the where you live.

And since curiosity has no age limit โ€“ adults, let us know what you’re wondering, too. We won’t be able to answer every question, but we will do our best.The Conversation

Hans Sues, Senior Research Geologist and Curator of Vertebrate Paleontology, Smithsonian Institution

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Read More

Advertisement

The post Could dinosaurs still exist somewhere in the world? A paleontologist explains appeared first on .com

The Conversation

Pagers and walkie-talkies over cellphones โ€“ a security expert explains why Hezbollah went low-tech for communications

Published

on

theconversation.com – Richard Forno, Principal Lecturer in Computer Science and Electrical Engineering, of Maryland, Baltimore County – 2024-09-18 16:32:21

A police officer examines a damaged car after thousands of pagers exploded simultaneously across Lebanon on Sept. 17, 2024.
AP Photo/Hussein Malla

Richard Forno, University of Maryland, Baltimore County

Electronic pagers across Lebanon exploded simultaneously on Sept. 17, 2024, killing 12 and wounding more than 2,700. The following day, another wave of explosions in the country came from detonating walkie-talkies. The attacks appeared to target members of the militant group Hezbollah.

The pagers attack involved explosives planted in the communications devices by Israeli operatives, according to U.S. cited by The New York Times. Hezbollah had recently ordered a shipment of pagers, according to the .

Advertisement

Secretly attacking the supply chain is not a new technique in intelligence and military operations. For example, the U.S. National Security Agency intercepted computer hardware bound for overseas customers, inserted malware or other surveillance tools and then repackaged them for delivery to certain foreign buyers, a 2010 NSA internal document showed. This differs from accessing a specific person’s device, such as when Israel’s Shin Bet secretly inserted explosives into a cellphone to remotely kill a Hamas bombmaker in 1996.

Hezbollah, a longtime adversary of Israel, had increased its use of pagers in the wake of the Hamas attack on Israel on Oct. 7, 2023. By shifting to relatively low-tech communication devices, pagers and walkie-talkies, Hezbollah apparently sought an advantage against Israel’s well-known sophistication in tracking targets through their phones.

pieces of a destroyed electronic device
The second wave of explosions in Lebanon involved walkie-talkies.
AP Photo

Cellphones: The ultimate tracker

As a former cybersecurity professional and current security researcher, I view cellular devices as the ultimate tracking tool for both government and commercial entities โ€“ in addition to users, criminals and the mobile phone provider itself. As a result, mobile phone tracking has contributed to the fight against terrorism, located missing people and helped solve crimes.

Conversely, mobile phone tracking makes it easy for anyone to record a person’s most intimate movements. This can be done for legitimate purposes such as parents tracking ‘s movements, helping you find your car in a parking lot, and commercial advertising, or nefarious ends such as remotely spying on a lover suspected of cheating or tracking political activists and journalists. Even the U.S. military remains concerned with how its soldiers might be tracked by their phones.

Mobile device tracking is conducted in several ways. First, there is the network location data generated by the phone as it moves past local cell towers or Stingray devices, which enforcement agencies use to mimic cell towers. Then there are the features built into the phone’s operating system or enabled by downloaded apps that may to highly detailed user tracking, which users unwittingly agree to by ignoring the software’s privacy policy or terms of service.

Advertisement

This collected data is sometimes sold to governments or other companies for additional data mining and user profiling. And modern smartphones also have built-in Bluetooth, Wi-Fi and GPS capabilities that can help with locating and tracking user movements around the world, both from the ground and via satellites.

Your phone contains many sensors that make it useful โ€“ and easy to track.

Mobile devices can be tracked in real time or close to it. Common technical methods include traditional radio direction-finding techniques, using intelligence satellites or drones, deploying โ€œman in the middleโ€ tools like Stingrays to impersonate cellular towers to intercept and isolate device traffic, or installing malware such as Pegasus, made by Israeli cyberarms company NSO to report a device’s location.

Nontechnical and slower techniques of user tracking include potentially identifying general user locations from their internet activity. This can be done from website logs or the metadata contained in content posted to social media, or contracting with data brokers to any collected location data from the apps that a user might install on their device.

Indeed, because of these vulnerabilities, the leader of Hezbollah earlier this year advised his members to avoid using cellular phones in their activities, noting that Israel’s โ€œsurveillance devices are in your pockets. If you are looking for the Israeli agent, look at the phone in your hands and those of your wives and children.โ€

Advertisement

Researchers have shown how these features, often intended for the user’s convenience, can be used by governments, companies and criminals to track people in their daily lives and even predict movements. Many people still aren’t aware of how much their mobile devices disclose about them.

Pagers, however, unlike mobile phones, can be harder to track depending on whether they support two-way communication.

Why go low-tech

A pager that only receives messages does not a signal that can facilitate tracking its owner. Therefore, Hezbollah’s use of pagers likely made it more challenging to track their operatives โ€“ thus motivating Israeli intelligence services’ purported attack on the supply chain of Hezbollah’s pagers.

Using low-tech tactics and personal couriers while avoiding the use of mobile phones and digital tools also made it difficult for the technologically superior Western intelligence agencies to locate Osama bin Laden for years after the 9/11 attacks.

Advertisement

In general, I believe the adversary in an asymmetric conflict using low-tech techniques, tactics and technology will almost always be able to operate successfully against a more powerful and well-funded opponent.

A well-documented demonstration of this asymmetry in action was the U.S. military’s Millennium Challenge war in 2002. Among other things, the insurgent Red forces, led by Marine General Paul van Riper, used low-tech tactics including motorcycle couriers instead of cellphones to evade the Blue forces’ high-tech surveillance. In the initial run of the exercise, the Red team won the contest in 24 hours, forcing exercise planners to controversially reset and update the scenario to ensure a Blue team victory.

Lessons for everyone

The preference for terrorist organizations like Hezbollah and al-Qaida to avoid using smartphones is a reminder for everyone that you can be, and likely are being tracked in various ways and for various purposes.

Israel’s purported response to Hezbollah’s actions also holds a lesson for everyone. From a cybersecurity perspective, it shows that any device in your life can be tampered with by an adversary at points along the supply chain โ€“ long before you even receive it.The Conversation

Richard Forno, Principal Lecturer in Computer Science and Electrical Engineering, University of Maryland, Baltimore County

Advertisement

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Read More

The post Pagers and walkie-talkies over cellphones โ€“ a security expert explains why Hezbollah went low-tech for communications appeared first on theconversation.com

Advertisement
Continue Reading

The Conversation

Tiny robots and AI algorithms could help to craft material solutions for cleaner environments

Published

on

theconversation.com – Mahshid Ahmadi, Assistant Professor of Materials Science and Engineering, of Tennessee – 2024-09-17 07:31:57

pollution is a global problem, but scientists are investigating new materials that could clean it up.
AP Photo/Sergei Grits

Mahshid Ahmadi, University of Tennessee

Many human activities release pollutants into the air, and soil. These harmful chemicals threaten the of both people and the ecosystem. According to the World Health Organization, air pollution causes an estimated 4.2 million deaths annually.

Scientists are looking into , and one potential avenue is a class of materials called photocatalysts. When triggered by light, these materials undergo chemical reactions that initial studies have shown can break down common toxic pollutants.

Advertisement

I am a materials science and engineering researcher at the University of Tennessee. With the help of robots and artificial intelligence, my colleagues and I are making and testing new photocatalysts with the goal of mitigating air pollution.

Breaking down pollutants

The photocatalysts work by generating charged carriers in the presence of light. These charged carriers are tiny particles that can move around and cause chemical reactions. When they into contact with water and oxygen in the , they produce substances called reactive oxygen species. These highly active reactive oxygen species can bond to parts of the pollutants and then either decompose the pollutants or turn them into harmless โ€“ or even useful โ€“ products.

A cube-shaped metal machine with a chamber filled with bright light, and a plate of tubes shown going under the light.
To facilitate the photocatalytic reaction, researchers in the Ahmadi lab put plates of perovskite nanocrystals and pollutants under bright light to see whether the reaction breaks down the pollutants.
Astita Dubey

But some materials used in the photocatalytic have limitations. For example, they can’t start the reaction unless the light has enough energy โ€“ infrared rays with lower energy light, or visible light, won’t trigger the reaction.

Another problem is that the charged particles involved in the reaction can recombine too quickly, which means they join back together before finishing the job. In these cases, the pollutants either do not decompose completely or the process takes a long time to accomplish.

Additionally, the surface of these photocatalysts can sometimes change during or after the photocatalytic reaction, which affects how they work and how efficient they are.

Advertisement

To overcome these limitations, scientists on my team are trying to develop new photocatalytic materials that work efficiently to break down pollutants. We also focus on making sure these materials are nontoxic so that our pollution-cleaning materials aren’t causing further pollution.

A plate of tiny tubes, with some colored dark blue, others light blue, and others transparent.
This plate from the Ahmadi lab is used while testing how perovskite nanocrystals and light break down pollutants, like the blue dye shown. The light blue color indicates partial degradation, while transparent water signifies complete degradation.
Astita Dubey

Teeny tiny crystals

Scientists on my team use automated experimentation and artificial intelligence to figure out which photocatalytic materials could be the best candidates to quickly break down pollutants. We’re making and testing materials called hybrid perovskites, which are tiny crystals โ€“ they’re about a 10th the thickness of a strand of hair.

These nanocrystals are made of a blend of organic (carbon-based) and inorganic (non-carbon-based) components.

They have a few unique qualities, like their excellent light-absorbing properties, which come from how they’re structured at the atomic level. They’re tiny, but mighty. Optically, they’re amazing too โ€“ they interact with light in fascinating ways to generate a large number of tiny charge carriers and trigger photocatalytic reactions.

These materials efficiently transport electrical charges, which allows them to transport light energy and drive the chemical reactions. They’re also used to make solar panels more efficient and in LED lights, which create the vibrant displays you see on TV screens.

Advertisement

There are thousands of potential types of hybrid nanocrystals. So, my team wanted to figure out how to make and test as many as we can quickly, to see which are the best candidates for cleaning up toxic pollutants.

Bringing in robots

Instead of making and testing samples by hand โ€“ which takes weeks or months โ€“ we’re using smart robots, which can produce and test at least 100 different materials within an hour. These small liquid-handling robots can precisely move, mix and transfer tiny amounts of liquid from one place to another. They’re controlled by a computer that guides their acceleration and accuracy.

A researcher in a white lab coat smiling at the camera next to a fume hood, with plates of small tubes inside it.
The Opentrons pipetting robot helps Astita Dubey, a visiting scientist working with the Ahmadi lab, synthesize materials and treat them with organic pollutants to test whether they can break down the pollutants.
Jordan Marshall

We also use machine learning to guide this process. Machine learning algorithms can analyze test data quickly and then learn from that data for the next set of experiments executed by the robots. These machine learning algorithms can quickly identify patterns and insights in collected data that would normally take much longer for a human eye to catch.

Our approach aims to simplify and better understand complex photocatalytic , helping to create new strategies and materials. By using automated experimentation guided by machine learning, we can now make these systems easier to analyze and interpret, overcoming challenges that were difficult with traditional methods.The Conversation

Mahshid Ahmadi, Assistant Professor of Materials Science and Engineering, University of Tennessee

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Advertisement

Read More

The post Tiny robots and AI algorithms could help to craft material solutions for cleaner environments appeared first on theconversation.com

Continue Reading

The Conversation

A public health historian sizes up their records

Published

on

theconversation.com – Zachary W. Schulz, Lecturer of History, Auburn University – 2024-09-17 07:33:53

The presidential debate on Sept. 10, 2024, did not add much context to what the two candidates would do on care beyond their own .
Visual China Group/Getty Images

Zachary W. Schulz, Auburn University

Health care is a defining issue in the 2024 election โ€“ Democratic presidential nominee Kamala Harris and Republican contender Donald Trump have starkly different records on the issue. Rather than focusing on what they promise to do, let’s examine what their past actions reveal about their approaches to Medicare, the Affordable Care Act, public health , drug policy and child abuse and domestic violence prevention.

As a specialist in public health history and policy, I have carefully examined both candidates’ records on American health care. With years of experience in the health care field and being a cystic fibrosis patient myself, I have developed a deep understanding of our health care system and the political dynamics that shape it.

Advertisement

For me, as for many other Americans, health care is more than just a political issue; it is a deeply personal one.

Medicare

During Harris’ time in the Senate, she co-sponsored the Medicare for All Act, which aimed to expand Medicare to all Americans, effectively eliminating private insurance.

At the presidential debate on Sept. 10, 2024, Harris clarified her former support of โ€œMedicare for Allโ€ by emphasizing her prior legislative efforts to preserve and expand protections for patients’ rights and access to affordable health care.

Harris’s legislative efforts, primarily around the 2017-2020 period, reflect a commitment to broadening access to Medicare and reducing costs for seniors. During that time, Harris advocated for the Medicare program to negotiate drug prices directly with pharmaceutical companies.

Advertisement

Later, as vice president, Harris cast a tie-breaking vote on the 2022 Inflation Reduction Act, allowing the government to negotiate drug prices for Medicare with pharmaceutical companies.

In contrast, during Trump’s presidency, he made several attempts, some of which were successful, to cut funding for Medicare. The 2020 budget proposed by his administration included cuts to Medicare totaling more than US$800 billion over 10 years, primarily by reducing payments to providers and slowing the growth of the program.

The proposed cuts did not take effect because they required Congressional approval, which was not granted. The plan significant opposition due to concerns about potential negative impacts on beneficiaries.

Affordable Care Act

Harris has been a staunch defender of the Affordable Care Act, also known as the ACA or โ€œObamacare.โ€ As a senator, Harris consistently voted against any efforts to repeal the ACA. She advocated for expanding its provisions, supporting legislation that aimed to strengthen protections for people with preexisting conditions and increase funding for Medicaid expansion.

Advertisement

Harris’ record shows a clear commitment to ensuring broader health coverage under the ACA. And, in the recent debate, Harris noted this record and reasserted her commitment to the act.

During his presidency, Trump led multiple efforts to repeal the ACA, including the 2017 American Health Care Act, which would have significantly reduced the scope of expansion and individual mandates.

Although these efforts ultimately failed in the Senate, Trump succeeded in weakening the ACA by eliminating the individual mandate penalty through the 2017 Tax Cuts and Jobs Act. In the debate against Harris, Trump reiterated his position that the Affordable Care Act โ€œwas lousy health care,โ€ though he did not ultimately offer a replacement plan, stating only that he has โ€œconcepts of a plan.โ€

Donald Trump claims that as president, he had an obligation to save Obamacare, otherwise known as the Affordable Care Act, but says it is too expensive. He says he has โ€˜concepts of a plan’ for something to replace the ACA.

Public health infrastructure

Harris’ tenure in the Senate, from January 2017 to January 2021, shows a consistent pattern of supporting public health infrastructure. She co-sponsored several bills aimed at increasing funding for community health centers and expanding access to preventive care.

Advertisement

Harris also advocated for more federal funding to address public health emergencies, such as the opioid epidemic and the COVID-19 pandemic.

During Trump’s presidency, however, he made significant cuts to public health programs. The Trump administration proposed budget cuts to the Centers for Disease Control and Prevention and other public health agencies, arguing that they were necessary for fiscal responsibility. These proposals drew criticism for potentially undermining the nation’s ability to respond to public health emergencies, a concern that was underscored by the CDC’s struggles during the early days of the COVID-19 pandemic. Trump frequently has responded to these criticisms by asserting he โ€œcut bureaucratic red tapeโ€ rather than essential services.

Drug pricing policy

Harris has also supported legislation to lower drug prices and increase transparency in the pharmaceutical industry. She co-sponsored the Drug Price Relief Act, which aimed to allow the federal government to negotiate drug prices for Medicare directly. She also supported efforts to import cheaper prescription from Canada. Her record reflects a focus on reducing costs for consumers and increasing access to affordable medications.

Trump’s record on drug policy is mixed. While Trump took credit for some decreases in prescription drug prices during his presidency, his administration’s most significant regulatory changes favored pharmaceutical companies. The administration’s attempts to implement a rule allowing the importation of cheaper drugs from Canada faced significant hurdles and did not lead to immediate changes.

Advertisement

Trump also ended a rule that would have required pharmaceutical companies to disclose drug prices in television ads, citing concerns over its legality.

Child abuse and domestic violence

Harris has a strong record of advocating for the prevention of child abuse and domestic violence. During her time as California’s attorney general and as a senator, Harris pushed for legislation that increased funding for domestic violence prevention programs and expanded legal protections for survivors. She has consistently supported measures to enhance child welfare services and improve coordination among agencies to protect children.

Trump’s record on these issues is less defined, but his administration did sign into law the Family First Prevention Services Act, which aimed to keep more safely at home and out of foster care by providing new resources to families. However, critics argue that the Trump administration’s broader cuts to social services and health programs could indirectly undermine efforts to combat child abuse and domestic violence. In addition, some experts suggest that Trump’s family separation policies on the southern border contributed to an increase in child trauma during his administration.The Conversation

Zachary W. Schulz, Lecturer of History, Auburn University

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Advertisement

Read More

The post A public health historian sizes up their records appeared first on .com

Continue Reading

Trending