Tag: History

Why 2,000 Year-Old Roman Concrete Is So Much Better Than What We Produce Today

roman

One of the fascinating mysteries of Ancient Rome is the impressive longevity of some of their concrete harbour structures. Battered by sea waves for 2,000 years, these things are still around while our modern concoctions erode over mere decades.

Now scientists have uncovered the incredible chemistry behind this phenomenon, getting closer to unlocking its long-lost recipe. As it turns out, not only is Roman concrete more durable than what we can make today, but it actually gets stronger over time.

Researchers led by geologist Marie Jackson from the University of Utah have been chipping away at the mysteries of Roman concrete for years, and now they have mapped its crystalline structure, figuring out precisely how this ancient material solidifies over time.




Modern concrete is typically made with portland cement, a mixture of silica sand, limestone, clay, chalk and other ingredients melted together at blistering temperatures. In concrete, this paste binds ‘aggregate’ – chunks of rock and sand.

This aggregate has to be inert, because any unwanted chemical reaction can cause cracks in the concrete, leading to erosion and crumbling of the structures. This is why concrete doesn’t have the longevity of natural rocks.

But that’s not how Roman concrete works.

Theirs was created with volcanic ash, lime and seawater, taking advantage of a chemical reaction Romans may have observed in naturally cemented volcanic ash deposits called tuff rocks.

Mixed in with the volcanic ash mortar was more volcanic rock as aggregate, which would then continue to react with the material, ultimately making Roman cement far more durable than you’d think it should be.

“We can go into the tiny natural laboratories in the concrete, map the minerals that are present, the succession of the crystals that occur, and their crystallographic properties,” says Jackson.

roman concrete

Aluminous tobermorite and a related mineral called phillipsite actually grows in the concrete thanks to the sea water sloshing around it, slowly dissolving the volcanic ash within and giving it space to develop a reinforced structure from these interlocking crystals.

“The Romans created a rock-like concrete that thrives in open chemical exchange with seawater,” says Jackson.

Making concrete the way Romans once did would be a boon to the modern building industry, but unfortunately the recipes have been lost to the tooth of time, so our only shot at recreating the ancient material is to reverse-engineer it based on what we know about its chemical properties.

“Romans were fortunate in the type of rock they had to work with,” says Jackson. “We don’t have those rocks in a lot of the world, so there would have to be substitutions made.”

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The World’s Oldest Piece Of Solid Cheese Was Found In An Egyptian Tomb

A solid white mass found in a broken jar in an Ancient Egyptian tomb has turned out to be the world’s oldest example of solid cheese.

Probably made mostly from sheep or goats milk, the cheese was found several years ago by archaeologists in the ancient tomb of Ptahmes, who was a high-ranking Egyptian official.

The substance was identified after the archaeology team carried out biomolecular identification of its proteins.

This 3,200-year-old find is exciting because it shows that the Ancient Egyptian’s shared our love of cheese — to the extent it was given as a funerary offering.

But not only that, it also fits into archaeology’s growing understanding of the importance of dairy to the development of the human diet in Europe.




Archaeological evidence

Using a technique called “lipid analysis“, sherds of ancient pottery can be analysed and fats absorbed into the clay identified. This then allows archaeologists to find out what was cooked or processed inside them.

Although it is not yet possible to identify the species of animal, dairy fats can be distinguished. It is also challenging to determine what techniques were being used to make dairy products safe to consume, with many potential options.

Fermenting milk, for example, breaks down the lactose sugar into lactic acid. Cheese is low in lactose because it involves separating curd from whey, in which the majority of the lactose sugars remain.

Clay sieves from Poland, similar to modern cheese sieves, have been found to have dairy lipids preserved in the pores of clay, suggesting that they were being used to separate curds from the whey.

Whether the curds were then consumed or attempts made to preserve them by pressing into a harder cheese is unknown.

Fermentation of milk was also possible to our ancestors, but harder to explore with the techniques currently available to archaeology.

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Investigating The 580-Million-Year-Old Fossil With CT Scan

ediacaran

The Ediacaran biota (flourished 579-541 Mya) forms an important and unresolved episode in the history of life. These organisms arose soon after the end of the major glaciations of the Cryogenian, and persisted until the beginning of the Cambrian.

They are thought to include some of the earliest animals. Understanding the nature and lifestyle of the Ediacaran organisms is therefore important in tracing the potentially long fuse of the Cambrian explosion.

Yet they remain puzzling. This project will use micro-CT to investigate two particularly contentious structures found in rocks of this age, and assess how they fit into the larger picture of the origin of multicellular animals in this age.

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Stew From A Polar Bear Liver Will Kill You In A Most Gruesome Way

Liver has long been a staple in many diets. Deep-fried chicken livers are a favorite in parts of the American South. Travel to Germany and you can feast on traditional liverwurst.

In Japan, you can order a heaping helping of sashimi made with raw fish liver. As delicious (or disgusting) as some of these dishes may sound to you, not every bird, fish or mammal necessarily offers the best ingredients for a culinary masterpiece.

In fact, if you ever have the chance to try polar bear liver, think twice — it may be the last meal you ever eat.

The native peoples of the Arctic have never shied away from cooking up some polar bear stew, but they’ve long known to avoid eating the livers of various arctic creatures.




Western explorers, however, learned the hard way. As early as 1596, explorers returned to Europe with accounts of horrible illnesses resulting from the consumption of polar bear liver.

Illness severity depended on how much liver the explorers consumed, but symptoms typically included drowsiness, sluggishness, irritability, severe headache, bone pain, blurred vision and vomiting.

Perhaps the most horrific symptom they encountered was peeling skin. While milder cases merely involved flaking around the mouth, some accounts reported cases of full-body skin loss.

Even the thick skin on the bottoms of a patient’s feet could peel away, leaving the underlying flesh bloody and exposed. The worst cases ended in liver damage, hemorrhage, coma and death.

These explorers suffered from acute hypervitaminosis A, a condition resulting from the overconsumption of vitamin A during a short period of time.

The polar bear’s liver, much like those of arctic seals and huskies, contains extremely high levels of retinol (the form of vitamin A found in members of the animal kingdom).

European Colonization Of Americas Wiped Out Native Dogs Alongside Indigenous People

European colonisers arriving in the Americas almost totally wiped out the dogs that had been kept by indigenous people across the region for thousands of years.

The original American dogs were brought across the land bridge that once connected North America and Siberia over 10,000 years ago, by their human owners.

These dogs subsequently spread throughout North and South America, but genetic analysis has revealed they were ultimately replaced by dogs imported from Europe.

This study demonstrates that the history of humans is mirrored in our domestic animals,” said Professor Greger Larson, director of the palaeogenomics and bio-archaeology research network at the University of Oxford and senior author of the research.

People in Europe and the Americas were genetically distinct, and so were their dogs. And just as indigenous people in the Americas were displaced by European colonists, the same is true of their dogs.




In their paper, published in the journal Science, the researchers compared genetic information from dozens of ancient North American and Siberian dogs spanning a period of 9,000 years.

Their analysis showed the dogs persisted for a long time but ultimately vanished, which to Dr Laurent Frantz from Queen Mary University of London said suggests “something catastrophic must have happened”.

It is fascinating that a population of dogs that inhabited many parts of the Americas for thousands of years, and that was an integral part of so many Native American cultures, could have disappeared so rapidly,” said Dr Frantz, who was also a senior author of the study.

Today, few modern dogs possess any genetic traces of the ancient breeds.

The researchers suggested the dogs’ near-total disappearance from the region was likely a result of both disease and cultural changes brought over by Europeans.

It is possible, for example, that European colonists discouraged the sale and breeding of the dogs kept by indigenous Americans.

It is known how indigenous peoples of the Americas suffered from the genocidal practices of European colonists after contact,” said Kelsey Witt, who led part of the genome work as a graduate student at the University of Illinois.

Bizarrely, one of the only traces of genetic information from “pre-contact” dogs can be found in a transmissible tumour that spreads between dogs known as CTVT.

It’s quite incredible to think that possibly the only survivor of a lost dog lineage is a tumour that can spread between dogs as an infection,” added Maire Ní Leathlobhair, co-first author, from the University of Cambridge.

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How People Really Lived During the Stone Age

cave man

The Paleo diet is just the beginning. It’s the gateway to an entire suite of lifestyle prescriptions devoted to mimicking the way our ancestors ate, moved, slept, and bred nearly 10,000 years ago in the Paleolithic era of hunting and gathering, an era Paleo followers associate with strong bodies and minds.

Members of this modern-day caveman community believe the path to optimal health is through eating only what our ancestors ate before modern agriculture and a shift to more sedentary ways.




Devoted proponents of a Paleo lifestyle not only subsist primarily on meat and eschew carbs; they also exercise in short bursts of activity intended to mimic escaping prey.

Even blood donation has become a Paleo fad among the most dogmatic of 21st-century cavemen, based on the notion that our ancestors were often wounded, making blood loss a way of life.

But new research reveals flaws in the logic behind these trends. As evolutionary and genetic science show, humans, like all other living beings, have always been a work in progress and never completely in sync with the natural world.

Survive-in-the-wild

If we’re going to romanticize and emulate a particular point in our evolutionary history, why not go all the way back to when our ape ancestors spent their days swinging from tree to tree?

It is hard to argue that a simpler life with more exercise, fewer processed foods, and closer contact with our children may well be good for us, but rather than renouncing modern living for the sake of our Stone Age genes, we need to understand how evolution has—and hasn’t—suited us for the world we inhabit now.

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The Mystery Of How Easter Island Statues Got Their Colossal Hats Might Finally Be Solved

It’s a towering problem, one to stump the most determined of milliners. You’ve carved almost 1,000 immense statues standing up to 10 metres (33 ft) tall. And now you want to put their hats on.

There’s just one problem. The hats, like the graven colossi themselves, are hewn out of solid rock, and weigh several tonnes a piece. How on Earth could you ever lift and fit this hulking headwear?

This ancient puzzle is just one of many posed by the strange stone legacy of Easter Island, whose unflinching moai statues maintain their silent vigil long centuries after the mysterious collapse of the Polynesian Rapa Nui society that erected them.

Of the many questions that surround the island’s past, two tend to stand out,” explains anthropologist Carl Lipo from Binghamton University.

How did people of the past move such massive statues, and how did they place such massive stone hats (pukao) on top of their heads?




Researchers already solved the first part of the puzzle. For decades, archaeologists have experimented with various methods of ‘walking’ the moai – rocking replica statues from side to side along prepared paths, ever slowly inching the towering figures forward.

It’s kind of like shuffling a fridge into a new kitchen (although decidedly more epic).

But what about the world’s heaviest hats?

In a new study, Lipo and his team suggest that the cylindrical pukao – with diameters up to 2 metres (6.5 feet) and weighing 12 tonnes – may have been rolled across the island from the red scoria quarries they were cut from.

A diagram of how the pukao might have been placed.

That’s how they were transported to the moai, but to lift them onto the statues’ elevated heads, props – and a little physics trickery – would be needed, with a ramp-and-ropes technique called parbuckling.

The solution may seem simple in hindsight, but to show that the hypothetical rig would have been workable for Rapa Nui islanders required building detailed 3D models of 50 pukao and 13 red scoria cylinders found on the island, and calculating how the huge hats may have been pulled up the inclined ahu platforms.

“Transport equations based on Newtonian physics, human strength estimates, and estimates of moai height and pukao mass at four different ahu verify that pukao transport by rolling up a ramp is physically feasible with 15 or fewer people,” the researchers write, “even in the case of the most massive pukao (about 12 metric tonnes).”

This technique means it wouldn’t have required huge number of peoples or resources to construct and assemble the moai and pukao, which helps discredit the view that the Rapa Nui may somehow have helped destroy their own civilisation through overpopulation taxing the island’s natural resources.

And yet, for all that ingenuity and coordinated effort, most of the pukao are sadly no longer affixed to the moai heads.

Centuries of weather, erosion, and animal activity have seen the majority of these rock hats fall back to Earth, where they rest crumbled and damaged around the island surface – which is one of the reasons you rarely see this monumental headwear in photos of the iconic statues.

Something to think about next time your hat blows off on a windy day.

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Here’s How To Purge Your Browsing History — No Questions Asked

Your online privacy is just as important as your offline privacy — if not more so. However, it’s not always easy to maintain.

Although surfing the internet in incognito mode is a great way to do so, it’s a good idea to know how to clear browsing history too. In this guide, we’ll walk you through it, no matter what browser you’re running.

If you want to go a step beyond this and keep your browsing history secret from remote services (and anyone who might be snooping on your connection), these are the best VPNs for both Windows and MacOSPCs.




Google Chrome

As the most popular web browser in the world, most of you are probably using Chrome. For the rest of you, scroll down, but if Chrome is your main browser, here’s how to clear your browsing history.

Step 1: Click the button represented by three vertical dots — it is located in the upper-right corner of your browser — to open a drop-down menu. Then select “Settings”.

Step 2: Scroll down and click the “Advanced” link next to the down-arrow.

Step 3: Scroll down until you see “Clear browsing data” and click it.

Step 4: This will open a window in which you can select the specific data you want to clear, including download history, passwords, and cookies. For our purposes, you should select Browsing history. You can also select the window of time you want to delete data from, whether it be the past hour or since the start of your browsing history.

Once you have decided how much data you want to delete, click “Clear browsing data.”

It’s a similar process for Chrome in MacOS, except that the three-dot button doesn’t exist. Instead, just click on Chrome in the menu bar and select on “Clear browsing data…” to get the screen options above.

Safari

The most common browser choice on Apple platforms, Safari, and its browsing history, is just as easy to clean out as Chrome’s.

Step 1: Find the “History” tab at the top of your screen and click “Clear History…

This will open a window that includes a drop-down menu, allowing you to decide what window of time you want to delete.

Once you select the time frame you want to delete, simply click the button labeled “Clear History.”

Firefox

Firefox’s new Quantum release could help return the browser to the popularity it once enjoyed. Here’s how to clear browsing history in Mozilla’s latest major release.

Step 1: Click the three-line button in the top right-hand corner and select “Options” from the resulting drop-down menu.

Step 2: Click the “Privacy and Security” tab and click “clear your recent history” under the “History” heading.

Step 3: A window will open, along with a drop-down menu where you can choose the amount of data you want to clear out. Click the “Details” arrow for more in-depth options if you prefer. Once you’ve made your decision, click “Clear Now.”

Opera

A long-running alternative to the big name browsers, Opera has remained competitive for more than two decades with good reason. Here’s how to clear its browsing history.

Step 1: Click the History icon in the left-hand menu. It looks like a small clock face.

Step 2: Click the “Clear browsing data” button on the right-hand side of the screen.

Step 3: Select the information you want to clear and the specific timeframe you want to be deleted, then click the blue “Clear browsing data” button.

Edge

The true successor to Microsoft’s Internet Explorer, Edge has proved to be a very capable modern browser. This is how to clear out your browsing history in it.

Step 1: Click the Hub button — it looks like unequal lines — then click the History button, which looks like a clock with an arrow running counter-clockwise.

Step 2:  select “Clear All History.” This will provide you with options outlining the types of data you can delete. Be sure to select “Browsing History.”

Step 3: Click the gray “Clear” button.

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All By Itself, The Humble Sweet Potato Colonized The World

A chromolithograph of Christopher Columbus arriving at the Caribbean.

Of all the plants that humanity has turned into crops, none is more puzzling than the sweet potato.

Indigenous people of Central and South America grew it on farms for generations, and Europeans discovered it when Christopher Columbus arrived in the Caribbean.

In the 18th century, however, Captain Cook stumbled across sweet potatoes again — over 4,000 miles away, on remote Polynesian islands. European explorers later found them elsewhere in the Pacific, from Hawaii to New Guinea.

The distribution of the plant baffled scientists. How could sweet potatoes arise from a wild ancestor and then wind up scattered across such a wide range?

Was it possible that unknown explorers carried it from South America to countless Pacific islands?

An extensive analysis of sweet potato DNA, published on Thursday in Current Biology, comes to a controversial conclusion: Humans had nothing to do with it.




The bulky sweet potato spread across the globe long before humans could have played a part — it’s a natural traveler.

Some agricultural experts are skeptical.

This paper does not settle the matter,” said Logan J. Kistler, the curator of archaeogenomics and archaeobotany at the Smithsonian Institution.

Alternative explanations remain on the table, because the new study didn’t provide enough evidence for exactly where sweet potatoes were first domesticated and when they arrived in the Pacific.

We still don’t have a smoking gun,” Dr. Kistler said.

The sweet potato, Ipomoea batatas, is one of the most valuable crops in the world, providing more nutrients per farmed acre than any other staple.  It has sustained human communities for centuries.

A sweet potato farmer in in Papua New Guinea. The plant arrived there long before humans, scientists reported.

 

Scientists have offered a number of theories to explain the wide distribution of I. batatas.

Some scholars proposed that all sweet potatoes originated in the Americas, and that after Columbus’s voyage, they were spread by Europeans to colonies such as the Philippines. Pacific Islanders acquired the crops from there.

As it turned out, though, Pacific Islanders had been growing the crop for generations by the time Europeans showed up. On one Polynesian island, archaeologists have found sweet potato remains dating back over 700 years.

A radically different hypothesis emerged: Pacific Islanders, masters of open-ocean navigation, picked up sweet potatoes by voyaging to the Americas, long before Columbus’s arrival there.

The evidence included a suggestive coincidence: In Peru, some indigenous people call the sweet potato cumara. In New Zealand, it’s kumara.

A potential link between South America and the Pacific was the inspiration for Thor Heyerdahl’s famous 1947 voyage aboard the Kon-Tiki. He built a raft, which he then successfully sailed from Peru to the Easter Islands.

Genetic evidence only complicated the picture. Examining the plant’s DNA, some researchers concluded that sweet potatoes arose only once from a wild ancestor, while other studies indicated that it happened at two different points in history.

According to the latter studies, South Americans domesticated sweet potatoes, which were then acquired by Polynesians. Central Americans domesticated a second variety that later was picked up by Europeans.

Hoping to shed light on the mystery, a team of researchers recently undertook a new study — the biggest survey of sweet potato DNA yet. And they came to a very different conclusion.

Their research pointed to only one wild plant as the ancestor of all sweet potatoes. The closest wild relative is a weedy flower called Ipomoea trifida that grows around the Caribbean.

Its pale purple flowers look a lot like those of the sweet potato.

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This Prehistoric ‘Sea Monster’ May Be Largest That Ever Lived

This reassembled jaw bone belonged to the 85-foot ichthyosaur.

The ancient remains of a gigantic marine reptile have been found in southwestern England.

Known as an ichthyosaur, the animal lived about 205 million years ago and was up to 85 feet long—almost as big as a blue whale, say the authors of a study describing the fossil published today in PLOS ONE.

Biology textbook have long touted the modern blue whale as the largest animal that ever lived, but this and other fascinating fossil finds hint that there may once have been even bigger creatures swimming Earth’s seas.

What is this animal?

Ichthyosaurs were ocean-going contemporaries of the dinosaurs, with body shapes superficially similar to dolphins.

They reached their greatest diversity about 210 million years ago in the late Triassic, but some persisted into the late Cretaceous.




They vanished from the fossil record about 25 million years before the mass extinction that wiped out the non-avian dinosaurs.

Most ichthyosaurs were much smaller than the newly discovered creature—several species in the genus Ichthyosaurus also found in the U.K. were just 5 to 11 feet long.

How did paleontologists find it?

Self-taught fossil hunter and study coauthor Paul de la Salle was combing the beach at Lilstock, Somerset, in May 2016 when he found a large and puzzling chunk of fossil bone.

Suspecting it might be an ichthyosaur, he sent images to marine reptile experts Dean Lomax at the University of Manchester in the U.K. and Judy Massare at SUNY Brockport in New York.

Further searching revealed five fossil pieces that fitted together to form a 3.2-foot-long bone, which the scientists identified as being from the lower jaw of an ichthyosaur.

Based on the size of the bone, the scientists think this ichthyosaur was bigger than any previously known to science.

Reconstructions of the giant ichthyosaur Shonisaurus show its skeletal structure and what it might have looked like in life.

Why is this discovery important?

Lomax says the discovery has led them to reinterpret a whole series of isolated bones found near the village of Aust in Gloucestershire, England.

Some collected as early as 1850, these fragments had long been interpreted to be the limb or other bones of terrestrial dinosaurs, but this never quite made sense.

The scientists realized these pieces also belonged to giant ichthyosaurs—and possibly to ones even bigger than the newly identified animal.

Darren Naish, a paleontologist at the University of Southampton in the U.K., agrees that the sizes of all these bones are astounding.

He is part of a different team that recently examined the Aust bones and similarly concluded that they belonged to enormous ichthyosaurs.

He concurs with the size estimates of the study authors, and says that these animals were “approaching or exceeding various giant baleen whales in size.

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