Lobotomy: Definition, Procedure & History

Lobotomy, also known as leucotomy, is a neurosurgical operation that involves severing connections in the brain's prefrontal lobe, according to Encyclopaedia Britannica. Lobotomies have always been controversial, but were widely performed for more than two decades as treatment for schizophrenia, manic depression and bipolar disorder, among other mental illnesses.

Lobotomy was an umbrella term for a series of different operations that purposely damaged brain tissue in order to treat mental illness, said Dr. Barron Lerner, a medical historian and professor at NYU Langone Medical Center in New York.

"The behaviors [doctors] were trying to fix, they thought, were set down in neurological connections," Lerner told Live Science. "The idea was, if you could damage those connections, you could stop the bad behaviors."

When lobotomy was invented, there were no good ways to treat mental illness, and people were looking for "pretty desperate" kinds of interventions, he said. Even so, there were always critics of the procedure, he added.

History

Doctors first began manipulating the brain to calm patients in the late 1880s, when the Swiss physician Gottlieb Burkhardt removed parts of the cortex of the brains of patients with auditory hallucinations and other symptoms of schizophrenia, noting that it made them calm (although one patient died and another committed suicide after the procedure), according to Encyclopaedia Britannica.

The Portuguese neurologist António Egas Moniz is credited with inventing the lobotomy in 1935, for which he shared the Nobel Prize for Physiology or Medicine in 1949 (later, a movement was started to revoke the prize, unsuccessfully).

Yale neuroscientist John Fulton and his colleague Carlyle Jacobsen had performed lobotomy-like procedures on chimpanzees in 1935. Moniz and his colleague Almeida Lima performed the first human experiments later that year. The frontal lobes were targeted because of their association with behavior and personality.

Moniz reported the treatment as a success for patients with conditions such as depression, schizophrenia, panic disorder and mania, according to an article published in 2011 in the Journal of Neurosurgery. But the operations had severe side effects, including increased temperature, vomiting, bladder and bowel incontinence and eye problems, as well apathy, lethargy, and abnormal sensations of hunger, among others. The medical community was initially critical of the procedure, but nevertheless, physicians started using it in countries around the world. 

Methods

The first procedures involved cutting a hole in the skull and injecting ethanol into the brain to destroy the fibers that connected the frontal lobe to other parts of the brain. Later, Moniz introduced a surgical instrument called a leucotome, which contains a loop of wire that, when rotated, creates a circular lesion in the brain.

Italian and American doctors were early adopters of the lobotomy. The American neurosurgeons Walter Freeman and James Watts adapted Moniz's technique to create the "Freeman-Watts technique" or the "Freeman-Watts standard prefrontal lobotomy," according to Encyclopaedia Britannica.

The Italian psychiatrist Amarro Fiamberti first developed a procedure that involved accessing the frontal lobes through the eye sockets, which would inspire Freeman to develop the transorbital lobotomy in 1945, a method that would not require a traditional surgeon and operating room. The technique involved using an instrument called an orbitoclast, a modified ice pick, which the physician would insert through the patient's eye socket using a hammer. They would then move the instrument side-to-side to separate the frontal lobes from the thalamus, the part of the brain that receives and relays sensory input.

Freeman wasn't just a neurologist, he was a showman, Lerner said. "He traveled around the country, doing multiple lobotomies in a day," he said. "He absolutely did this for way too long."

Prevalence & effects

About 50,000 lobotomies were performed in the United States, and Freeman himself performed between 3,500 and 5,000.

While a small percentage of people supposedly got better or stayed the same, for many people, lobotomy had negative effects on a patient's personality, initiative, inhibitions, empathy and ability to function on their own.

"The main long-term side effect was mental dullness," Lerner said. People could no longer live independently, and they lost their personalities, he said.

Mental institutions played a critical role in the prevalence of lobotomy. At the time, there were hundreds of thousands of mental institutions, which were overcrowded and chaotic. By giving unruly patients lobotomies, doctors could maintain control over the institution, Lerner said.

That's exactly what happens in the 1962 novel and 1975 film "One Flew Over the Cuckoo's Nest," in which Randall Patrick McMurphy, a rambunctious but sane man living in a mental hospital, is given a lobotomy that leaves him mute and vacant-minded.

"Usually things in movies are exaggerated," Lerner said. But in this case, it was "disturbingly real," he said.

The practice started subsiding in the mid-1950s, as scientists developed antipsychotic and antidepressant medications that were much more effective. Nowadays, mental illness is primarily treated with drugs. In cases where drugs are not effective, people may be treated with electroconvulsive therapy, a procedure that involves passing electrical currents through the brain to trigger a brief seizure, according to the Mayo Clinic. 

Lobotomy is rarely, if ever, performed today, and if it is, "it’s a much more elegant procedure," Lerner said. "You're not going in with an ice pick and monkeying around." The removal of specific brain areas (psychosurgery) is only used to treat patients for whom all other treatments have failed.

What Is Civil Engineering?

Civil engineering is the design and construction of public works, such as dams, bridges and other large infrastructure projects. It is one of the oldest branches ofengineering, dating back to when people first started living in permanent settlements and began shaping their environments to suit their needs. 

Early engineers built walls, roads, bridges, dams and levees; they dug wells, irrigation ditches and trenches. As larger groups of people began living together in towns and cities, these populations needed reliable sources of clean water, the means to dispose of waste, a network of streets and roadways for commerce and trade, and a way to defend themselves against hostile neighbors. 

Ancient civil engineering projects include the roads of the Roman Empire, the Great Wall of China, the cliff dwellings at Mesa Verde and Mayan ruins at Copan, Palenque and Tikal. Many early civilizations built monuments to their rulers or gods. These may have been simple mounds or truly remarkable achievements, such as the Pyramids of Giza and Stonehenge, whose construction by pre-industrial societies remains mysterious. The names of the engineers who designed these wonders are lost to antiquity. 

Today, the public is more likely to remember the names of great civil engineering projects than the names of the engineers who designed and built them. These include the Brooklyn Bridge (designed by John August Roebling and son Washington Roebling), the Hoover Dam (John L. Savage), the Panama Canal (John Frank Stevens) and the Golden Gate Bridge (Joseph Strauss and Charles Ellis). One notable exception is theEiffel Tower, named after Gustave Eiffel, the French civil engineer whose company built it. 

What does a civil engineer do?

Civil engineers "design, construct, supervise, operate and maintain large construction projects and systems, including roads, buildings, airports, tunnels, dams, bridges, and systems for water supply and sewage treatment," according to the U.S. Bureau of Labor Statistics(BLS). 

These engineers may also handle site preparation activities, such as excavation, earth moving and grading for large construction projects. Additionally, civil engineers may conduct or write the specifications for destructive or nondestructive testing of the performance, reliability and long-term durability of materials and structures. 

Here are some recent and ongoing civil engineering projects of note:

• A team of researchers from Johns Hopkins University conducted tests to see how well buildings made of cold-formed steel can withstand earthquakes. 
• Engineers at the University of Maryland are working on smart bridges that can send out warnings when they are in danger of collapsing.
• In Los Angeles, civil engineers who are experts in structural monitoring helped art conservators preserve the iconic Watts Towers monument.

What a civil engineer needs to know

Today's civil engineers need in-depth understanding of physics, mathematics, geology and hydrology. They must also know the properties of a wide range of construction materials, such as concrete and structural steel, and the types and capabilities of construction machinery. With this knowledge, engineers can design structures that meet requirements for cost, safety, reliability, durability and energy efficiency. Civil engineers also need a working knowledge of structural and mechanical engineering. 

These engineers can be involved in nearly every stage of a major construction project. That can include site selection, writing specifications for processes and materials, reviewing bids from subcontractors, ensuring compliance with building codes, and supervising all phases of construction from grading and earth moving to painting and finishing. 

More and more, civil engineers rely on computer-aided design (CAD) systems; therefore, proficiency with computers is essential. In addition to speeding up the drafting process for civil engineering projects, CAD systems make it easy to modify designs and generate working blueprints for construction crews. A comprehensive list of necessary skills and abilities for civil engineers can be found at MyMajors.com. 

Civil engineering jobs & salary

The BLS states, "Civil engineers generally work indoors in offices. However, many spend time outdoors at construction sites so they can monitor operations or solve problems onsite." Most civil engineers employed in the private sector work for large construction contractors or as consultants. Government institutions that employ civil engineers include state transportation departments and the military. 

Most civil engineering jobs require at least a bachelor's degree in engineering. Many employers, particularly those that offer engineering consulting services, also require state certification as a professional engineer. Additionally, many employers require certification from theAmerican Society of Civil Engineers (ASCE). A master's degree is often required for promotion to management, and ongoing education and training are needed to keep up with advances in technology, equipment, computer hardware and software, building codes, and other government regulations. 

According to Salary.com, as of July 2014, the salary range for a newly graduated civil engineer with a bachelor's degree is $55,570 to $73,908. The range for a mid-level engineer with a master's degree and five to 10 years of experience is $74,007 to $108,640, and the range for a senior engineer with a master's degree or doctorate and over 15 years of experience is $97,434 to $138,296. Many experienced engineers with advanced degrees are promoted to management positions or start their own businesses where they can earn even more. 

The future of civil engineering

Employment of civil engineers is projected to grow 20 percent from now to 2022, faster than the average for all occupations, according to the BLS. "As infrastructure continues to age, civil engineers will be needed to manage projects to rebuild bridges, repair roads, and upgrade levees and dams," the BLS said. There should be many opportunities for qualified applicants, particularly those who have kept abreast of the latest developments in technology and regulations. Having good grades from a highly rated institution should give a job seeker an advantage over the competition. 

Three Things You Didn’t Know About the Arachnids That Live on Your Face

You are not alone. Your body is a collection of microbes, fungi, viruses…and even other animals. In fact, you aren’t even the only animal using your face. Right now, in the general vicinity of your nose, there are at least two species of microscopic mites living in your pores. You would expect scientists to know quite a lot about these animals (given that we share our faces with them), but we don’t.

Here is what we do know: Demodex mites are microscopic arachnids (relatives of spiders and ticks) that live in and on the skin of mammals – including humans. They have been found on every mammal species where we’ve looked for them, except the platypus and their odd egg-laying relatives.

Often mammals appear to host more than one species, with some poor field mouse species housing four mite species on its face alone. Generally, these mites live out a benign coexistence with their hosts. But if that fine balance is disrupted, they are known to cause mange amongst our furry friends, and skin ailments like rosacea and blepharitis in humans. Most of us are simply content – if unaware – carriers of these spindly, eight-legged pore-dwellers.

Scientists from NC State, the North Carolina Museum of Natural Sciences, and the California Academy of Sciences have just published a study that uncovers some previously unknown truths regarding these little-known mites – all the while providing a glimpse into even bigger mysteries that have yet to be solved.

1. Everyone has mites.

One of our most exciting discoveries is that these mites are living on everyone. Yes everyone (even you). This hasn’t always been obvious because it can be hard to find a microscopic mite living on one’s face. Traditional sampling methods (including scraping or pulling a piece of tape off your face) only return mites on 10-25 percent of adults. The fact that mites are found at a much higher rate on cadavers (likely because the dead are easier to sample more extensively and intrusively) was a hint that they might be much more ubiquitous.

As it turns out, you don’t have to actually see a mite to detect its presence. Dan Fergus, a mite molecular biologist at the North Carolina Museum of Natural Sciences, discovered that mite DNA could be sequenced from face scrapings regardless of whether a mite could be found under the microscope. And mite DNA was sequenced from every adult we sampled. Meaning that if you let us scrape your face, we’d find mite DNA on you as well. And where mite DNA is found, you’ll find mites. 

2. Humans host two mite species that aren’t closely related to each other.

One of the most intriguing (and unsolved) face mite mysteries is how humans acquired these beasties. Perhaps these mites are a model system of co-evolution. It’s possible that as every species of mammal evolved, so did their mites – each one particularly adapted to its changed environs. In such a case, we would expect that we acquired our mites from our ape ancestors, and that the two species of human mites would be more closely related to each other than to any other mite species.

However, we’ve learned that the two mite species on our faces Demodex folliculorum(the long skinny one, pictured at the top of this post) and Demodex brevis (the short, chubby one, photo to the right) are actually not very close relatives to each other at all. Our analyses actually show that brevis is more closely related to dog mites than tofolliculorum, the other human mite. This is interesting because it shows us that humans have acquired each of these mite species in different ways, and that there are two separate histories of how each of these mite species came to be on our face.

Though we don’t have enough evidence to say that we got one of our mites from man’s best friend, it does seem possible that one of the domestic animal species that we’ve long shared our lives with (be it dogs, goats or otherwise) may have gifted us their mites.

3. Mites can tell us about the historical divergence of human populations

How we acquired our mites is just one part of the story. We are also curious about how our mite species have evolved since they became our constant companions.

Demodex have likely been living with us for a long, long time; as early humans walked out of Africa and found their way around the globe, they probably carried their mites with them. So we want to know if Demodex DNA can provide a reflection of our own evolutionary history by allowing us to retrace those ancient paths of human migration.

So far, our analyses look promising. When looking at the DNA from one of our mite species, D. brevis, we found that mites from China are genetically distinct from mites from the Americas. East Asians and European populations diverged over 40,000 years ago and so far it looks like their mites did as well. On the other hand, D. folliculorumfrom China is indistinguishable from that of the Americas. Of the two Demodexspecies associated with humans, D. brevis lives deeper in your pores than folliculorumand is probably shared between people less readily, whereas D. folliculorum appears to enjoy global domination.

But as exciting as these results are, China and the US are just a small piece of the picture. We can’t wait to see what happens when we sample D. brevis from people all over the world! The ancient journey of Homo sapiens as retold by mites.

If reading this made your face a little itchy, rest easy. In an evolutionary perspective, humans and Demodex are old, old friends. You are in good company. And so are your mites.

Editor’s Note: This is a guest post by Michelle Trautwein, adjunct assistant professor of entomology at NC State and Schlinger Chair of Dipterology at the California Academy of Sciences.

The paper, “Ubiquity and diversity of human associated Demodex mites,” is published in PLOS ONE. Lead author of the paper is Megan Thoemmes, a Ph.D. student at NC State. Co-authors include Trautwein, Fergus, Julie Urban of the North Carolina Museum of Natural Sciences, and Rob Dunn, an associate professor of biology at NC State. The research was supported by NASA, under grant ROSES NNX09AK22G, and the National Science Foundation, under grant 0953390.

Suicide is Not 'Unavoidable

Everyone has their share of bad days, but when feelings such as worthlessness, helplessness, or hopelessness become predominant in everyday life, there may be a more serious issue at hand.

According to the U.S. Centers for Disease Control and Prevention (CDC), mental illness is responsible for more disability than any other specific illness in developed countries, with about 25 percent of all U.S. adults suffering from some sort of mental illness and nearly 50 percent of adults experiencing at least one mental illness during their lifetime. Depression, in particular, is a whole-body source of suffering and disability that can alter the way a person thinks, feels, and acts. Although deceptively common, depression is often tragically linked to suicide.

In fact, within the past decade, suicide rates in the United States significantly increased after a previous decade of decline. It's not clear why this is, but it's probably not just from one reason. And that's the challenge presented by suicide — it's a multifaceted problem that requires multifaceted solutions. The passing of Hollywood icon Robin Williams recently shed light on how profoundly depression can affect an individual's life. Williams, arguably one of America's favorite actors, killed himself in his own home after a lifelong struggle with depression, drug addiction and alcoholism, complicated by the recent diagnosis of Parkinson's disease. 

At face value, not many people would have guessed that he had suffered so terribly and for so long. A revered actor, he endeared himself to the world, not just by virtue of his comic genius, but also by his warmth and sweetness of character. While his death seems especially cruel in reminding us that mental illness has the potential to undermine anyone, it also creates an opportunity to share the news that depression is highly treatable and that suicide is preventable. 

Unfortunately, depression is a widely misunderstood and stigmatized disease. Although excellent treatments are available and it is the rare individual who will not respond to treatment, sometimes even wealth, resources and connections are insufficient in engaging sufferers with the good treatment they deserve. 

For example, suicide rates for middle-aged white men — who tend to have the resources at hand to treat their disease — have gone up tremendously in the last ten years, though researchers have not pinpointed the exact reason why. That said, based on what we now know about treatment, we should be unwilling to accept even a single suicide as being unavoidable. 

Depression is not the same as just being in a bad or unhappy mood. The diagnosis depends on a combination of symptoms that are sufficiently severe to impair an individual's day-to-day functions. Recognizing depression is crucial to helping people heal, although signs of depression can be tricky to spot or easily dismissed as "normal." 

There are a few common signs of depression to look out for. Contact your primary health care provider if you begin to notice changes in ourself, or a loved one, such as:

Often feeling depressed, down, sad, angry or irritable.

Loss of interest and pleasure in activities formerly enjoyed.

• Noticeable increase or decrease in appetite or weight, not attributable to dieting or deliberate effort. 
• Noticeable change in sleep pattern, such as fitful sleep, difficulty falling or staying asleep, early morning awakening, or sleeping more than usual.
• Fatigue or loss of energy. 
• Being noticeably slowed down or agitated in thinking or behavior.
• Inappropriate or excessive feelings of worthlessness or guilt.
• Diminished ability to concentrate or make decisions.
• Recurrent thoughts of death or suicide. 

It is also common for people who are depressed to feel overwhelmed and to suffer from otherwise unexplained, but real physical symptoms like headache, gastrointestinal distress or chronic pain. 

Depression can also sometimes distort thinking and generate unrealistic beliefs, a condition known as psychotic depression that can be reversed with treatment. 

Because each patient dealing with depression is unique, treatment must be individualized. This is especially true when "first line" treatments, such as psychotherapy or an antidepressant, alone are not successful. In such circumstance, a careful evaluation for potential medical causes of depression can be helpful, and it is often useful to combine modern psychotherapy and antidepressant medication, as science tells us that the combination of medication and psychotherapy is typically superior to either treatment alone. 

We also know that skillfully changing or combining antidepressants can produce potentially life-changing results. Even more exciting are new treatments that make use of weak electrical current and magnetic fields to improve mood and return individuals to health. 

Here at Ohio State's Wexner Medical Center, we offer treatments such as transcranial magnetic stimulation (TMS), as well as a modern, safe and effective version of electroconvulsive therapy (ECT). Depressed individuals who are discouraged by lack of progress need to understand that promising treatments are available, and that the persistence of patients and doctors is most often rewarded with success.

Depression is a serious illness that requires and deserves immediate care. If you or anyone you know thinks they may be suffering from depression, get ahead of the illness early to ensure a promising and happy future. Treatment really can make a difference and even prove lifesaving. 

New Dates for Prehistoric Paintings in Utah’s Great Gallery

LOGAN, UTAH— A team led by Utah State University geologist Joel Pederson has used luminescence dating techniques to document the timing of geologic events in southern Utah’s Canyonlands National Park, and thus “draw a box” around a probable window of time for the creation of the paintings in Horseshoe Canyon’s Great Gallery. “The most accepted hypotheses pointed to the age of these paintings as 2,000 to 4,000 years old or perhaps even 7,000 to 8,000 years old. Our findings reveal these paintings were likely made between 1,000 and 2,000 years ago,” Pederson told Phys.org. The new dates suggest that the artists may have co-existed with the Fremont people, who are known for their carved pictographs. “Previous ideas suggested a people different from the Fremont created the paintings because the medium and images are so different. This raises a lot of archaeological questions,” Pederson explained. To learn more about art from this period in Southwestern prehistory, see "Investigating A Decades-Old Disapperance," ARCHAEOLOGY's account of a mystery involving Fremont figurines.

Who Crafted Saudi Arabia’s 100,000-Year-Old Stone Tools?

BORDEAUX, FRANCE—A team of researchers led by Eleanor Scerri of the University of Bordeaux compared stone artifacts unearthed from three sites in the Arabian Desert with artifacts discovered in northeast Africa near the skeletons of modern humans. All of the tools were between 70,000 and 125,000 years old. Live Science reports that the artifacts from two of the three Arabian sites were “extremely similar” to the tools from northeast Africa, suggesting that the groups may have had some interaction, and that the Arabian tools could have been made by modern humans. The tools from the third Arabian site were “completely different,” however, and may have been crafted by a different human lineage. “It seems likely that there were multiple dispersals into the Arabian Peninsula from Africa, some possibly very early in the history of Homo sapiens. It also seems likely that there may have been multiple dispersals into this region from other parts of Eurasia. These features are what make the Arabian Peninsula so interesting,” Scerri explained. To see how this discovery might complement recent DNA work, see ARCHAEOLOGY's "Turning Back the Human Clock."

Turning Back the Human Clock

For years, archaeologists and geneticists have been troubled by the fact that their time lines for key events in human evolution don’t always match up. While archaeologists rely on the dating of physical remains to determine when and how human beings spread across the globe, geneticists use a DNA “clock” based on the assumption that the human genome mutates at a constant rate. By comparing differences between modern and ancient DNA, geneticists then calculate when early humans diverged from other species and when human populations formed different genetic groups.

The DNA clock is a powerful tool, but its conclusions—for example, that modern humans first emerged from Africa about 60,000 years ago—can disagree with archaeological evidence that shows signs of modern human activity well before that date at sites in regions as far-flung as Arabia, India, and China.

Now, new work, based on observation of the genetic differences between present-day parents and children, suggests that the genetic clock may actually run about twice as slowly as previously believed, at least for the last million years or so of primate history. In their review paper in the journal Nature Reviews Genetics, Aylwyn Scally and Richard Durbin of the Wellcome Trust Sanger Institute in Hinxton, England, propose much earlier dates for watershed events in human evolution, which could help bring the genetic and archaeological records in line. For instance, a slower clock places the migration of modern humans out of Africa at around 120,000 years ago, which is more consistent with archaeological evidence.

The revised clock also supports archaeological signs of modern human activity from more than 60,000 years ago at sites such as Jwalapuram, India (“Stone Age India,” January/February 2010), and Liujiang, China—evidence that has often been dismissed by geneticists as impossible. While more work is needed to confirm the findings, Scally says that archaeologists who work on such sites should be excited: “It can no longer be said that the genetic evidence is unequivocally against them.”

Nanodiamonds are forever: Did comet collision leave layer of nanodiamonds across Earth?

Date:

August 27, 2014

Source:

University of California - Santa Barbara

Summary:

A group of scientists, including UC Santa Barbara's James Kennett, professor emeritus in the Department of Earth Science, posited that a comet collision with Earth played a major role in the extinction. Their hypothesis suggests that a cosmic-impact event precipitated the Younger Dryas period of global cooling close to 12,800 years ago. This cosmic impact caused abrupt environmental stress and degradation that contributed to the extinction of most large animal species then inhabiting the Americas. According to Kennett, the catastrophic impact and the subsequent climate change also led to the disappearance of the prehistoric Clovis culture, known for its big game hunting, and to human population decline.in a new study published this week in the Journal of Geology, Kennett and an international group of scientists have focused on the character and distribution of nanodiamonds, one type of material produced during such an extraterrestrial collision. The researchers found an abundance of these tiny diamonds distributed over 50 million square kilometers across the Northern Hemisphere at the Younger Dryas boundary (YDB). This thin, carbon-rich layer is often visible as a thin black line a few meters below the surface

Kennett and investigators from 21 universities in six countries investigated nanodiamonds at 32 sites in 11 countries across North America, Europe and the Middle East. Two of the sites are just across the Santa Barbara Channel from UCSB: one at Arlington Canyon on Santa Rosa Island, the other at Daisy Cave on San Miguel Island."We conclusively have identified a thin layer over three continents, particularly in North America and Western Europe, that contain a rich assemblage of nanodiamonds, the production of which can be explained only by cosmic impact," Kennett said. "We have also found YDB glassy and metallic materials formed at temperatures in excess of 2200 degrees Celsius, which could not have resulted from wildfires, volcanism or meteoritic flux, but only from cosmic impact."

Most of North America's megafauna -- mastodons, short-faced bears, giant ground sloths, saber-toothed cats and American camels and horses -- disappeared close to 13,000 years ago at the end of the Pleistocene period. The cause of this massive extinction has long been debated by scientists who, until recently, could only speculate as to why.

The team found that the YDB layer also contained larger than normal amounts of cosmic impact spherules, high-temperature melt-glass, grapelike soot clusters, charcoal, carbon spherules, osmium, platinum and other materials. But in this paper the researchers focused their multi-analytical approach exclusively on nanodiamonds, which were found in several forms, including cubic (the form of diamonds used in jewelry) and hexagonal crystals.

"Different types of diamonds are found in the YDB assemblages because they are produced as a result of large variations in temperature, pressure and oxygen levels associated with the chaos of an impact," Kennett explained. "These are exotic conditions that came together to produce the diamonds from terrestrial carbon; the diamonds did not arrive with the incoming meteorite or comet."

Based on multiple analytical procedures, the researchers determined that the majority of the materials in the YDB samples are nanodiamonds and not some other kinds of minerals. The analysis showed that the nanodiamonds consistently occur in the YDB layer over broad areas.

"There is no known limit to the YDB strewnfield which currently covers more than 10 percent of the planet, indicating that the YDB event was a major cosmic impact," Kennett said. "The nanodiamond datum recognized in this study gives scientists a snapshot of a moment in time called an isochron."

To date, scientists know of only two layers in which more than one identification of nanodiamonds has been found: the YDB 12,800 years ago and the well-known Cretaceous-Tertiary boundary 65 million years ago, which is marked by the mass extinction of the dinosaurs, ammonites and many other groups.

"The evidence we present settles the debate about the existence of abundant YDB nanodiamonds," Kennett said. "Our hypothesis challenges some existing paradigms within several disciplines, including impact dynamics, archaeology, paleontology and paleoceanography/paleoclimatology, all affected by this relatively recent cosmic impact."

A comet collision with Earth caused abrupt environmental stress and degradation that contributed to the extinction of most large animal species then inhabiting the Americas, a group of scientists suggests. The catastrophic impact and the subsequent climate change also led to the disappearance of the prehistoric Clovis culture, and to human population decline. Now focus has turned to the character and distribution of nanodiamonds, one type of material produced during such an extraterrestrial collision. The researchers found an abundance of these tiny diamonds distributed over 50 million square kilometers across the Northern Hemisphere.

Early growth of giant galaxy, just 3 billion years after the Big Bang, revealed

Date:

August 27, 2014

Source:

Space Telescope Science Institute (STScI)

Summary:

The birth of massive galaxies, according to galaxy formation theories, begins with the buildup of a dense, compact core that is ablaze with the glow of millions of newly formed stars. Evidence of this early construction phase, however, has eluded astronomers — until now. Astronomers identified a dense galactic core, dubbed "Sparky," using a combination of data from several space telescopes. Hubble photographed the emerging galaxy as it looked 11 billion years ago, just 3 billion years after the birth of our universe in the big bang.

Astronomers have for the first time gotten a glimpse of the earliest stages of massive galaxy construction. The building site, dubbed "Sparky," is a developing galaxy containing a dense core that is blazing with the light of millions of newborn stars which are forming at a ferocious rate. The discovery was made possible through combining observations from NASA's Hubble and Spitzer space telescopes, the European Space Agency's Herschel Space Observatory, and the W.M. Keck Observatory in Hawaii.

Because the infant galaxy is so far away, it is seen as it appeared 11 billion years ago, just 3 billion years after the birth of the universe in the big bang. Astronomers think the compact galaxy will continue to grow, possibly becoming a giant elliptical galaxy, a gas-deficient assemblage of ancient stars theorized to develop from the inside out, with a compact core marking its beginnings.

"We really hadn't seen a formation process that could create things that are this dense," explained Erica Nelson of Yale University in New Haven, Connecticut, lead author of the science paper announcing the results. "We suspect that this core-formation process is a phenomenon unique to the early universe because the early universe, as a whole, was more compact. Today, the universe is so diffuse that it cannot create such objects anymore."

The research team's paper appears in the August 27 issue of the journal Nature.

Although only a fraction of the size of the Milky Way, the tiny powerhouse galaxy already contains about twice as many stars as our galaxy, all crammed into a region only 6,000 light-years across. The Milky Way is about 100,000 light-years across. The barely visible galaxy may be representative of a much larger population of similar objects that are obscured by dust.

"They're very extreme environments," Nelson said. "It's like a medieval cauldron forging stars. There's a lot of turbulence, and it's bubbling. If you were in there, the night sky would be bright with young stars, and there would be a lot of dust, gas, and remnants of exploding stars. To actually see this happening is fascinating."

Alongside determining the galaxy's size from the Hubble images, the team dug into archival far-infrared images from the Spitzer and Herschel telescopes. The analysis allowed them to see how fast the young galaxy is churning out stars. Sparky is producing roughly 300 stars per year. By comparison, the Milky Way produces roughly 10 stars per year.

Astronomers believe that this frenzied star formation occurred because the galactic center is forming deep inside a gravitational well of dark matter, an invisible form of matter that makes up the scaffolding upon which galaxies formed in the early universe. A torrent of gas is flowing into this well at the galaxy's core, sparking waves of star birth.

The sheer amount of gas and dust within an extreme star-forming region like this may explain why these compact galaxies have eluded astronomers until now. Bursts of star formation create dust, which builds up within the forming galaxy and can block some starlight. Sparky was only barely visible, and it required the infrared capabilities of Hubble's Wide Field Camera 3, Spitzer, and Herschel to reveal the developing galaxy.

The observations indicate that the galaxy had been furiously making stars for more than a billion years (at the time the light we now observe began its long journey). But the galaxy didn't keep up this frenetic pace for very long, the researchers suggested. Eventually, the galaxy probably stopped forming stars in the packed core. Smaller galaxies then might have merged with the growing galaxy, making it expand outward in size over the next 10 billion years, possibly becoming similar to one of the mammoth, sedate elliptical galaxies seen today.

"I think our discovery settles the question of whether this mode of building galaxies actually happened or not," said team member Pieter van Dokkum of Yale University. "The question now is, how often did this occur? We suspect there are other galaxies like this that are even fainter in near-infrared wavelengths. We think they'll be brighter at longer wavelengths, and so it will really be up to future infrared telescopes such as NASA's James Webb Space Telescope to find more of these objects."

Detecting neutrinos, physicists look into the heart of the sun

Date:

August 27, 2014

Source:

University of Massachusetts at Amherst

Summary:

Using one of the most sensitive neutrino detectors on the planet, physicists have directly detected neutrinos created by the 'keystone' proton-proton fusion process going on at the sun's core for the first time.

sing one of the most sensitive neutrino detectors on the planet, an international team of physicists including Andrea Pocar, Laura Cadonati and doctoral student Keith Otis at the University of Massachusetts Amherst report in the current issue of Nature that for the first time they have directly detected neutrinos created by the "keystone" proton-proton (pp) fusion process going on at the sun's core.

The pp reaction is the first step of a reaction sequence responsible for about 99 percent of the Sun's power, Pocar explains. Solar neutrinos are produced in nuclear processes and radioactive decays of different elements during fusion reactions at the Sun's core. These particles stream out of the star at nearly the speed of light, as many as 420 billion hitting every square inch of the Earth's surface per second.

Because they only interact through the nuclear weak force, they pass through matter virtually unaffected, which makes them very difficult to detect and distinguish from trace nuclear decays of ordinary materials, he adds.

The UMass Amherst physicist, one principal investigator on a team of more than 100 scientists, says, "With these latest neutrino data, we are directly looking at the originator of the sun's biggest energy producing process, or chain of reactions, going on in its extremely hot, dense core. While the light we see from the Sun in our daily life reaches us in about eight minutes, it takes tens of thousands of years for energy radiating from the sun's center to be emitted as light."

"By comparing the two different types of solar energy radiated, as neutrinos and as surface light, we obtain experimental information about the Sun's thermodynamic equilibrium over about a 100,000-year timescale," Pocar adds. "If the eyes are the mirror of the soul, with these neutrinos, we are looking not just at its face, but directly into its core. We have glimpsed the sun's soul."

"As far as we know, neutrinos are the only way we have of looking into the Sun's interior. These pp neutrinos, emitted when two protons fuse forming a deuteron, are particularly hard to study. This is because they are low energy, in the range where natural radioactivity is very abundant and masks the signal from their interaction."

The Borexino instrument, located deep beneath Italy's Apennine Mountains, detects neutrinos as they interact with the electrons of an ultra-pure organic liquid scintillator at the center of a large sphere surrounded by 1,000 tons of water. Its great depth and many onion-like protective layers maintain the core as the most radiation-free medium on the planet.

Indeed, it is the only detector on Earth capable of observing the entire spectrum of solar neutrino simultaneously. Neutrinos come in three types, or "flavors." Those from the Sun's core are of the "electron" flavor, and as they travel away from their birthplace, they oscillate or change between two other flavors, "muon" to "tau." With this and previous solar neutrino measurements, the Borexino experiment has strongly confirmed this behavior of the elusive particles, Pocar says.

One of the crucial challenges in using Borexino is the need to control and precisely quantify all background radiation. Pocar says the organic scintillator at Borexino's center is filled with a benzene-like liquid derived from "really, really old, millions-of-years-old petroleum," among the oldest they could find on Earth.

"We needed this because we want all the Carbon-14 to have decayed, or as much of it as possible, because carbon-14 beta decays cover the neutrino signals we want to detect. We know there is only three atoms of C14 for each billion, billion atoms in the scintillator, which shows how ridiculously clean it is."

A related problem the physicists discuss in their new paper is that when two C14 atoms in the scintillator decay simultaneously, an event they call a "pileup," its signature is similar to that of a pp solar neutrino interaction. In a great advance for the analysis, Pocar says, "Keith Otis figured out a way to solve the problem of statistically identifying and subtracting these pileup events from the data, which basically makes this new pp neutrino analysis process possible."

Though detecting pp neutrinos was not part of the original National Science Foundation-sponsored Borexino experiment, "it's a little bit of a coup that we could do it," the astrophysicist says. "We pushed the detector sensitivity to a limit that has never been achieved before."

Neuroscientists reverse memories' emotional associations: Brain circuit that links feelings to memories manipulated

Date:

August 27, 2014

Source:

Massachusetts Institute of Technology

Summary:

Most memories have some kind of emotion associated with them: Recalling the week you just spent at the beach probably makes you feel happy, while reflecting on being bullied provokes more negative feelings. A new study from neuroscientists reveals the brain circuit that controls how memories become linked with positive or negative emotions.

A new study from MIT neuroscientists reveals the brain circuit that controls how memories become linked with positive or negative emotions. Furthermore, the researchers found that they could reverse the emotional association of specific memories by manipulating brain cells with optogenetics -- a technique that uses light to control neuron activity.The findings, described in the Aug. 27 issue ofNature, demonstrated that a neuronal circuit connecting the hippocampus and the amygdala plays a critical role in associating emotion with memory. This circuit could offer a target for new drugs to help treat conditions such as post-traumatic stress disorder, the researchers say.

Most memories have some kind of emotion associated with them: Recalling the week you just spent at the beach probably makes you feel happy, while reflecting on being bullied provokes more negative feelings.

"In the future, one may be able to develop methods that help people to remember positive memories more strongly than negative ones," says Susumu Tonegawa, the Picower Professor of Biology and Neuroscience, director of the RIKEN-MIT Center for Neural Circuit Genetics at MIT's Picower Institute for Learning and Memory, and senior author of the paper.

The paper's lead authors are Roger Redondo, a Howard Hughes Medical Institute postdoc at MIT, and Joshua Kim, a graduate student in MIT's Department of Biology.

Shifting memories

Memories are made of many elements, which are stored in different parts of the brain. A memory's context, including information about the location where the event took place, is stored in cells of the hippocampus, while emotions linked to that memory are found in the amygdala.

Previous research has shown that many aspects of memory, including emotional associations, are malleable. Psychotherapists have taken advantage of this to help patients suffering from depression and post-traumatic stress disorder, but the neural circuitry underlying such malleability is not known.

In this study, the researchers set out to explore that malleability with an experimental technique they recently devised that allows them to tag neurons that encode a specific memory, or engram. To achieve this, they label hippocampal cells that are turned on during memory formation with a light-sensitive protein called channelrhodopsin. From that point on, any time those cells are activated with light, the mice recall the memory encoded by that group of cells.

Last year, Tonegawa's lab used this technique to implant, or "incept," false memories in mice by reactivating engrams while the mice were undergoing a different experience. In the new study, the researchers wanted to investigate how the context of a memory becomes linked to a particular emotion. First, they used their engram-labeling protocol to tag neurons associated with either a rewarding experience (for male mice, socializing with a female mouse) or an unpleasant experience (a mild electrical shock). In this first set of experiments, the researchers labeled memory cells in a part of the hippocampus called the dentate gyrus.

Two days later, the mice were placed into a large rectangular arena. For three minutes, the researchers recorded which half of the arena the mice naturally preferred. Then, for mice that had received the fear conditioning, the researchers stimulated the labeled cells in the dentate gyrus with light whenever the mice went into the preferred side. The mice soon began avoiding that area, showing that the reactivation of the fear memory had been successful.

The reward memory could also be reactivated: For mice that were reward-conditioned, the researchers stimulated them with light whenever they went into the less-preferred side, and they soon began to spend more time there, recalling the pleasant memory.

A couple of days later, the researchers tried to reverse the mice's emotional responses. For male mice that had originally received the fear conditioning, they activated the memory cells involved in the fear memory with light for 12 minutes while the mice spent time with female mice. For mice that had initially received the reward conditioning, memory cells were activated while they received mild electric shocks.

Next, the researchers again put the mice in the large two-zone arena. This time, the mice that had originally been conditioned with fear and had avoided the side of the chamber where their hippocampal cells were activated by the laser now began to spend more time in that side when their hippocampal cells were activated, showing that a pleasant association had replaced the fearful one. This reversal also took place in mice that went from reward to fear conditioning.

Altered connections

The researchers then performed the same set of experiments but labeled memory cells in the basolateral amygdala, a region involved in processing emotions. This time, they could not induce a switch by reactivating those cells -- the mice continued to behave as they had been conditioned when the memory cells were first labeled.

This suggests that emotional associations, also called valences, are encoded somewhere in the neural circuitry that connects the dentate gyrus to the amygdala, the researchers say. A fearful experience strengthens the connections between the hippocampal engram and fear-encoding cells in the amygdala, but that connection can be weakened later on as new connections are formed between the hippocampus and amygdala cells that encode positive associations.

"That plasticity of the connection between the hippocampus and the amygdala plays a crucial role in the switching of the valence of the memory," Tonegawa says.

These results indicate that while dentate gyrus cells are neutral with respect to emotion, individual amygdala cells are precommitted to encode fear or reward memory. The researchers are now trying to discover molecular signatures of these two types of amygdala cells. They are also investigating whether reactivating pleasant memories has any effect on depression, in hopes of identifying new targets for drugs to treat depression and post-traumatic stress disorder.

David Anderson, a professor of biology at the California Institute of Technology, says the study makes an important contribution to neuroscientists' fundamental understanding of the brain and also has potential implications for treating mental illness.

"This is a tour de force of modern molecular-biology-based methods for analyzing processes, such as learning and memory, at the neural-circuitry level. It's one of the most sophisticated studies of this type that I've seen," he says.