NEW YORK — Mike and Hillary 2020? Never say never.Mike Bloomberg’s presidential campaign pointedly refused to deny reports Saturday that he is considering Hillary Clinton as a possible running mate.“We’re focused on the campaign and the debate, not vice presidential speculation,” said Jason Schechter, chief communications officer for Bloomberg’s campaign.An unnamed Bloomberg campaign source told the Drudge Report that the billionaire ex-mayor is thinking about the failed 2016 presidential candidate as the No. 2 person on a Democratic ticket led by him to take on President Donald Trump.The atte...
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You only get 52 teeth in your lifetime: 20 baby teeth, followed by 32 adult teeth.
It’s not like that for all animals. Some, like rodents, never replace their teeth. Others, like sharks, keep replacing them again and again.
So why do we humans replace our teeth only once? And how does the whole tooth replacement process work?
These are tricky questions, and we don’t have all the answers. But a new discovery about the strange tooth-replacement habits of the tammar wallaby, a small Australian marsupial, may help shed some light on this dental mystery.
Not everybody replaces teeth the same way
It has been long assumed modern mammals all replace their teeth the same way. However, advances in 3D scanning and modelling have revealed mammals with unusual tooth replacement, like the tammar wallaby (Macropus eugenii) and the fruit bat (Eidolon helvum).
These mammals have given us important clues as to how humans and other mammals have evolved from ancestors with continuous tooth replacement.
How do humans make and replace teeth?
Human teeth begin growing between the sixth and eighth week of an embryo’s development, when a band of tissue within the gums called the primary dental lamina starts to thicken. Along this band, clusters of special stem cells appear at the sites of future teeth, known as “placodes”.
The placodes then begin to grow into teeth, going through the bud, cap and bell stages along the way. They form into their final shape and harden with layers of dentine and enamel. Eventually, they will erupt through the gums. The incisors are the first to erupt, as early as 6 months old, which is why its called theteethingphase!
This generation of teeth, which grow from the primary dental lamina, are known as “primary dentition”, or baby teeth.
Secondary or adult teeth grow a little bit differently. An offshoot of tissue called the successional lamina grows out from the baby tooth, and that tissue develops the replacement tooth like an apple on a branch of a tree. Adult teeth begin to grow before we are born, but take many years for the full set to form and eventually appear.
Replacement occurs when the adult teeth get large enough that they finally push out the baby teeth and remain as the permanent set of teeth for the rest of our lives. The first molar usually erupts between 6 and 7 years of age, while our wisdom teeth are the last to appear (roughly between 17 and 21 years of age).
Most mammals replace their teeth once in the course of their lives, like we do. This is known as “diphyodonty” (two sets of teeth).
Some groups of mammals, such as rodents, don’t replace their teeth at all. These “monophyodonts” get by with the same set of teeth for their whole lives. There are also a few unusual mammals, such as echidnas, that don’t grow any teeth at all!
Learning from the wallaby
The tammar wallaby is also a diphyodont, replacing its teeth only once.
Scientists long assumed it replaced its teeth in the same way humans do, though historical notes going back as far as 1893 noticed unusual things about this marsupial’s tooth development. For starters, while we replace our incisors, canines and premolars, tammar wallabies only replace their premolars.
Baby and adult teeth of the tammar wallaby. Scale bar equals 1 cm. Nasrullah et al.
Recently my colleagues at Monash University and the University of Melbourne and I observed the teeth of tammar wallabies from the embryo through to adulthood. We used a technique called diceCT, which combines staining and CT scanning, and found something surprising.
Instead of replacement premolar teeth developing from the successional lamina, they were in fact delayed baby teeth developing from the primary dental lamina.
This means the tammar wallaby does not have any traditional tooth replacement. This discovery opens up a huge set of new questions. What exactly are these teeth?
Tooth development of premolars in the tammar wallaby in 2D and 3D, showing the delayed baby tooth ‘P3’ appearing 47 days after its siblings ‘dP2’ and ‘dP3’
One explanation for these delayed baby teeth could be a link to our ancestry of continuous tooth replacement.
Your teeth are millions of years in the making
Unlike mammals, most other animals, including fish, sharks, amphibians and reptiles, replace their teeth multiple times (they are “polyphyodonts”). Mammals lost this ability around 205 million years ago.
The reason we stop making teeth is because our dental lamina degrades after our second set are made, while it remains active in polyphyodonts.
Interestingly, in modern and fossil polyphyodonts the replacement teeth often develop in groups of alternating waves, known as “Zahnreihen”.
While the tammar only replaces its premolars, these delayed baby teeth could represent the presence of the Zahnreihen still occurring in modern mammals.
This gives us a clue about how we have evolved from ancestors with continuous tooth replacement: by modifying and reducing a system that is hundreds of millions of years old.
In reptiles, teeth are replaced in waves, or ‘Zahnreihen’. Each blue line shows a single wave.
Research has also found that fruit bats (Eidolon helvum) make replacement teeth in unusual ways, including growing them in front of the baby tooth, behind it, beside it, or splitting off from it.
This is exciting because, together with the tammar, it shows there may well be a wealth of tooth replacement diversity across mammals happening right under our noses – or our gums!
1836 Project’s pamphlet to promote a 'patriotic' version of Texas history airbrushes oppression and poverty, experts say
By Sneha Dey, The Texas Tribune
Sept. 26, 2022
A committee charged with producing a “patriotic” telling of Texas history approved a 15-page pamphlet last month that will now be distributed to new Texas drivers.
The advisory committee — named the 1836 Project after the year Texas gained its independence from Mexico — was created last year with the passing of House Bill 2497. The legislation required the committee to tell a story of “a legacy of economic prosperity” and the “abundant opportunities for businesses and families, among other requirements.”
“We must never forget why Texas became so exceptional in the first place,” Gov. Greg Abbott said when he signed the bill. Abbott, along with Lt. Gov. Dan Patrick and House Speaker Dade Phelan, later selected a nine-member, largely conservative group to head the 1836 Project.
The creation of the committee was largely a conservative backlash to The New York Times’ publication of “The 1619 Project,” which was named after the year enslaved people first arrived on American soil and aimed to center slavery in conversations about U.S. history. The pamphlet, which will be distributed at driver’s license offices, comes at a time when the state is increasingly trying to regulate how race, sexuality and history are taught in public schools.
The Texas Tribune reviewed the 1836 Project committee’s final pamphlet and asked historians to comment on how accurately and thoroughly the document chronicles the state’s history.
The historians acknowledged that the committee had a difficult assignment; Donald Frazier, the chair of the subcommittee in charge of drafting the pamphlet, called squeezing the entirety of the state’s history into little more than a dozen pages a “herculean task.”
But the historians also noted that condensing the state’s history and painting it in a mostly celebratory light came at a cost. The pamphlet, they said, fails to fully hold institutions accountable for slavery and other forms of oppression and shortchanged Indigenous Texans, Tejanos, Black Texans and women.
The pamphlet engages with contemporary research — like literature about the lasting impact of the Confederacy — but also tries to fulfill state lawmakers’ wish to promote “patriotic education” and avoid disturbing Texas’ myths, said Raúl A. Ramos, a history professor at the University of Houston.
“The traditional mythic version of Texas history, it’s about the heroes of the Alamo having pure intentions of liberty and freedom in the abstract rather than the liberty to conquer Indigenous and Mexican lands and freedom to own enslaved people,” Ramos said. “It’s that abstract idea that is attractive and powerful and [that’s what] people gravitate towards, and I think that’s what people associate with patriotism.”
Below is a look at how the Project 1836 advisory committee’s pamphlet discusses four areas of Texas’ history — early settlements, the oil and cotton industries, the Alamo and slavery — and the historians’ notes on what the document’s authors chose to play up, play down or omit.
Trinidad Gonzalez, a history professor at South Texas College, said the pamphlet aggrandizes Manifest Destiny, the belief that American settlers had the God-given right to expand across North America. It’s an idea about early settlements that was driven by 19th century nationalism and exceptionalism.
In the opening paragraph, the pamphlet says the land of Texas seemed like “an inhospitable zone to many,” but Americans “with fortitude and nerve” saw the opportunities and made the region productive.
“It wasn’t just the Americans who thought it was boundless opportunities. [The pamphlet’s authors] are trying to create the simplified Manifest Destiny story that fits this older myth of white Americans coming in and basically building Texas,” Gonzalez said. “And when you do that, then you silence everybody else that participated in the history of Texas.”
Historians told the Tribune that the pamphlet glosses over the Indigenous, Spanish and Mexican populations that resided before, saying Texas was “nearly depopulated” before American settlers migrated to the land.
However, the Indigenous population significantly outnumbered American settlers in 1836, Gonzalez said. The stretch of land from the Rio Grande Valley to Laredo was also once one of the most economically successful Spanish settlements, he added.
Emilio Zamora, a history professor at the University of Texas at Austin, called the pamphlet’s interpretation of early settlements in Texas “very unsettling.”
The document “speaks very negatively about the Mexicans and the colonial settlers that preceded them,” Zamora said.
Oil, not cotton
When it comes to the state’s economy, the pamphlet zeros in on the oil industry. The discovery of oil “ushered in a period of remarkable transformation,” the pamphlet says. It characterizes the wildcatter and oil derrick as “Texas icons.”
Nowadays, West Texas’ Permian Basin is the nation’s most productive oil region. The Permian produces more than 5 million barrels of the nation’s daily output of 11.6 million barrels of oil per day.
But before oil, there was cotton. Texas still leads the nation in cotton production. Cotton continues to be the state’s largest agricultural export and is responsible for thousands of jobs across sectors, such as ginning companies, warehouses and oil mill processing plants.
The 1836 Project pamphlet mentions oil five times. It never mentions cotton.
The pamphlet highlights Houston’s title as “energy capital of the world,” but cotton used to be so essential to the city that it would celebrate the crop with festivals, naming a symbolic leader for the carnival King Nottoc (“cotton” spelled backwards).
The pamphlet “ignores the reality that cotton production and poverty long characterized much of the Texas economy after the Civil War and through 1940. Instead it glamorizes the oil industry,” said Walter Buenger, a history professor at UT-Austin.
Buenger said that the state’s dependence on cotton made Texas one of the poorest states in the country.
The cotton market had globalized and become increasingly competitive, but the state delayed mechanizing cotton production to continue offering low-skilled jobs that had low returns. It resulted in an unequal distribution of income: While a handful of cotton traders got “fabulously wealthy,” most Texans struggled to survive, Buenger said.
“Through 1940, Texas was, for the most part, very poor. And they were poor because they were wrapped up in this cotton production business,” Buenger explained.
The Alamo, the Spanish mission founded in the 18th century in what is now San Antonio, has long been enshrined as “the cradle of Texas liberty.” The men who died as Mexican troops laid siege on the Alamo are often remembered as heroic martyrs who valued liberty over their lives.
“Only Texas could turn defeat into a legend — and a song, and a tourist attraction, and a major motion picture,” author Rosemary Kent famously said of the Alamo.
But the 1836 Project pamphlet does not dwell on the Alamo. Of the document’s 4,517 words, just 87 are spent on the siege.
Gene Preuss, an associate professor of history at the University of Houston-Downtown, called that a notable move away from traditionalist history in a state where the Alamo has often been at the center of Texas politics and history.
“There really isn’t much discussion of the Alamo in the pamphlet,” he said. “And I find that interesting because a lot of traditional histories would focus on the Alamo.”
In fitting the Battle of the Alamo into one abridged paragraph, the pamphlet’s authors appear to acknowledge the recent efforts to reexamine the historic event.
“For a long time, Texas history has been taught from one perspective,” Preuss said. “I think [the pamphlet] does enough to open some cracks, which I as a professor can open further for my students so that when they come into class, they don’t say things like ‘I didn’t know [Black Texans] participated in the Texas revolution’ [or] ‘I didn’t know Tejanos were on the side of Texians and died at the Alamo.’”
But the pamphlet also avoids going into that reexamination. It doesn’t mention, for instance, the issues brought up in the book “Forget the Alamo,” which was published last year and prompted the lieutenant governor to push for the cancellation of an event featuring the title at the Bullock Texas State History Museum. The book highlights how the defense of slavery played a key role in the conflict with Mexico and questions the garrison defenders’ military strategy.
When the 1836 Project committee was established, Nikole Hannah-Jones, creator of “The 1619 Project,” feared that the 1836 Project was another attempt to veil the nation’s history of slavery.
“When it comes to slavery, some people have never wanted open debate and honesty. They seek to bury and prohibit instead,” Hannah-Jones said on Twitter.
The pamphlet does mention slavery, acknowledging that it became an economic engine for the state. Republican lawmakers also required that the document mention how on June 19, 1865, the date that became the basis for Juneteenth, Union soldiers in Galveston announced the liberation of all enslaved people.
“We wanted to reemphasize and make dang true that everybody understands that slavery was a bad thing and Texas participated,” Frazier, the chair of the subcommittee in charge of drafting the pamphlet, said at the August committee meeting.
But many of the historians the Tribune spoke with said the pamphlet doesn’t go far enough, noting that it omits how central defending slavery was in the Texas war of secession from Mexico and the Civil War. They say it airbrushes gruesome accounts of how enslaved people were treated.
“Slavery is mentioned only as a complication that delayed annexation by the United States. The pamphlet never names any enslaved individuals, nor does it describe their fight for freedom,” historians Leah LaGrone and Michael Phillips wrote in a Texas Monthly column.
Ramos, the history professor at the University of Houston, said the pamphlet’s treatment of slavery is an example of how the document takes a passive, ambiguous approach to inequity and oppression that doesn’t hold Americans who participated in institutions accountable.
The pamphlet, he said, is a document birthed out of a political process and should be read as such.
“Sometimes people interpret history as being political, as being a way people might signal their politics,” Ramos said. “But it’s also political in that way that is part of how we view ourselves as people, as a community, and how we continue to either build community or divide community.”
Disclosure: Bullock Texas State History Museum, Texas Monthly, The New York Times, the University of Texas at Austin, the University of Houston and the University of Houston-Downtown have been financial supporters of The Texas Tribune, a nonprofit, nonpartisan news organization that is funded in part by donations from members, foundations and corporate sponsors. Financial supporters play no role in the Tribune’s journalism. Find a complete list of them here.
This article originally appeared in The Texas Tribune at https://www.texastribune.org/2022/09/26/texas-1836-project-pamphlet/.
The Texas Tribune is a member-supported, nonpartisan newsroom informing and engaging Texans on state politics and policy. Learn more at texastribune.org.
NASA will on Monday attempt a feat humanity has never before accomplished: deliberately smacking a spacecraft into an asteroid to slightly deflect its orbit, in a key test of our ability to stop cosmic objects from devastating life on Earth.
The Double Asteroid Redirection Test (DART) spaceship launched from California last November and is fast approaching its target, which it will strike at roughly 14,000 miles (22,500 kilometers) per hour.
To be sure, neither the asteroid moonlet Dimorphos, nor the big brother it orbits, called Didymos, pose any threat as the pair loop the Sun, passing about seven million miles from Earth at nearest approach.
But NASA has deemed the experiment important to carry out before an actual need is discovered.
If all goes to plan, impact between the car-sized spacecraft, and the 530-foot (160 meters, or two Statues of Liberty) asteroid should take place at 7:14 pm Eastern Time (2314 GMT), and can be followed on a NASA livestream.
By striking Dimorphos head on, NASA hopes to push it into a smaller orbit, shaving ten minutes off the time it takes to encircle Didymos, which is currently 11 hours and 55 minutes -- a change that will be detected by ground telescopes in the days that follow.
The proof-of-concept experiment will make a reality of what has before only been attempted in science fiction -- notably films such as "Armageddon" and "Don't Look Up."
As the craft propels itself through space, flying autonomously for the mission's final phase, its camera system will start to beam down the very first pictures of Dimorphos.
Minutes later, a toaster-sized satellite called LICIACube, which separated from DART a couple of weeks earlier, will make a close pass of the site to capture images of the collision and the ejecta -- the pulverized rock thrown off by impact.
LICIACube's pictures will be sent back in the weeks and months that follow.
Also watching the event: an array of telescopes, both on Earth and in space -- including the recently operational James Webb -- which might be able to see a brightening cloud of dust.
Finally, a full picture of what the system looks like will be revealed when a European Space Agency mission four years down the line called Hera arrives to survey Dimorphos's surface and measure its mass, which scientists can only guess at currently.
Very few of the billions of asteroids and comets in our solar system are considered potentially hazardous to our planet, and none are expected in the next hundred or so years.
But "I guarantee to you that if you wait long enough, there will be an object," said NASA's Thomas Zurbuchen.
We know that from the geological record -- for example, the six-mile wide Chicxulub asteroid struck Earth 66 million years ago, plunging the world into a long winter that led to the mass extinction of the dinosaurs along with 75 percent of all species.
An asteroid the size of Dimorphos, by contrast, would only cause a regional impact, such as devastating a city, albeit with greater force than any nuclear bomb in history.
How much momentum DART imparts on Dimorphos will depend on whether the asteroid is solid rock, or more like a "rubbish pile" of boulders bound by mutual gravity, a property that's not yet known.
The shape of the asteroid is also not known, but NASA engineers are confident DART's SmartNav guidance system will hit its target.
If it misses, NASA will have another shot in two years' time, with the spaceship containing just enough fuel for another pass.
But if it succeeds, Chabot said, the mission will mark the first step towards a world capable of defending itself from a future existential threat.
© 2022 AFP