Computers can also be programed to match names and faces, study says
February 27, 2017
American Psychological Association
If your name is Fred, do you look like a Fred? You might — and others might think so, too. New research has found that people appear to be better than chance at correctly matching people’s names to their faces, and it may have something to do with cultural stereotypes we attach to names.
If your name is Fred, do you look like a Fred? You might — and others might think so, too. New research published by the American Psychological Association has found that people appear to be better than chance at correctly matching people’s names to their faces, and it may have something to do with cultural stereotypes we attach to names.
In the study, published in the Journal of Personality and Social Psychology, lead author Yonat Zwebner, a PhD candidate at The Hebrew University of Jerusalem at the time of the research, and colleagues conducted a series of experiments involving hundreds of participants in Israel and France. In each experiment, participants were shown a photograph and asked to select the given name that corresponded to the face from a list of four or five names. In every experiment, the participants were significantly better (25 to 40 percent accurate) at matching the name to the face than random chance (20 or 25 percent accurate depending on the experiment) even when ethnicity, age and other socioeconomic variables were controlled for.
The researchers theorize the effect may be, in part, due to cultural stereotypes associated with names as they found the effect to be culture-specific. In one experiment conducted with students in both France and Israel, participants were given a mix of French and Israeli faces and names. The French students were better than random chance at matching only French names and faces and Israeli students were better at matching only Hebrew names and Israeli faces.
In another experiment, the researchers trained a computer, using a learning algorithm, to match names to faces. In this experiment, which included over 94,000 facial images, the computer was also significantly more likely (54 to 64 percent accuracy) to be successful than random chance (50 percent accuracy).
This manifestation of the name in a face might be due to people subconsciously altering their appearance to conform to cultural norms and cues associated with their names, according to Zwebner.
“We are familiar with such a process from other stereotypes, like ethnicity and gender where sometimes the stereotypical expectations of others affect who we become,” said Zwebner. “Prior research has shown there are cultural stereotypes attached to names, including how someone should look. For instance, people are more likely to imagine a person named Bob to have a rounder face than a person named Tim. We believe these stereotypes can, over time, affect people’s facial appearance.”
This was supported by findings of one experiment showing that areas of the face that can be controlled by the individual, such as hairstyle, were sufficient to produce the effect.
“Together, these findings suggest that facial appearance represents social expectations of how a person with a particular name should look. In this way, a social tag may influence one’s facial appearance,” said co-author Ruth Mayo, PhD, also from The Hebrew University of Jerusalem. “We are subject to social structuring from the minute we are born, not only by gender, ethnicity and socioeconomic status, but by the simple choice others make in giving us our name.”
- Ruth Mayo et al. We Look Like Our Names: The Manifestation of Name Stereotypes in Facial Appearance. Journal of Personality and Social Psychology, February 2017 DOI: 10.1037/pspa0000076
Source: American Psychological Association. “Do you look like your name? People can match names to faces of strangers with surprising accuracy: Computers can also be programed to match names and faces, study says.” ScienceDaily. ScienceDaily, 27 February 2017. <www.sciencedaily.com/releases/2017/02/170227100804.htm>.
Orchid Blossoms on the 24th Floor in February
Every year or so, an orchid blossoms in the corner office of Target Health Inc. on the 24th Floor at 261 Madison. With the temperature in February reaching 60 degrees in NYC, maybe Biology is telling us something.
Orchid Blossoms on 24th Floor ©Target Health Inc.
For more information about Target Health contact Warren Pearlson (212-681-2100 ext. 165). For additional information about software tools for paperless clinical trials, please also feel free to contact Dr. Jules T. Mitchel or Ms. Joyce Hays. The Target Health software tools are designed to partner with both CROs and Sponsors. Please visit the Target Health Website.
Joyce Hays, Founder and Editor in Chief of On Target
Jules Mitchel, Editor
QUIZ – Gall Bladder
Source: From Wikimedia Commons, the free media repository
The gallbladder is a small pouch that sits just under the liver and stores bile produced by the 1) ___. After meals, the gallbladder is empty and flat, like a deflated balloon. Before a meal, the gallbladder may be full of bile and about the size of a small pear. In response to signals, the gallbladder squeezes stored 2) ___ into the small intestine through a series of tubes called ducts. Bile helps digest fats, but the gallbladder itself is not essential. Removing the gallbladder in an otherwise healthy individual typically causes no observable problems with health or digestion yet there may be a small risk of diarrhea and fat malabsorption. For unclear reasons, substances in bile can crystallize in the gallbladder, forming gallstones. Common and usually harmless, 3) ___ can sometimes cause pain, nausea, or inflammation. t’s not clear what causes gallstones to form. Doctors think gallstones may result when your bile contains too much cholesterol. Normally, bile contains enough chemicals to dissolve the cholesterol excreted by the liver. But if the liver excretes more cholesterol than the bile can dissolve, the excess cholesterol may form into crystals and eventually into stones. Too much bilirubin may be another cause of gallstones. Bilirubin is a chemical that’s produced when the body breaks down red blood cells. Certain conditions cause the liver to make too much bilirubin, including liver cirrhosis, biliary tract infections and certain blood disorders. The excess bilirubin contributes to gallstone formation. If the gallbladder doesn’t empty completely or often enough, bile may become very concentrated, contributing to the formation of gallstones.
Inflammation of the gallbladder is called cholecystitis, and is often due to a gallstone in the gallbladder. Cholecystitis causes severe pain and fever, and can require surgery when 4) ___ continues or recurs. Although rare, 5) ___ of the gallbladder can affect the gallbladder. It is difficult to diagnose and usually found at late stages when symptoms appear. Symptoms may resemble those of gallstones. An impacted gallstone can block the ducts that drain the pancreas. Inflammation of the pancreas, or pancreatitis, is the result, a serious condition. Abdominal ultrasound is a noninvasive diagnostic test in which a probe on the skin bounces high-frequency sound waves off structures in the belly. Abdominal 6) ___ is an excellent test for gallstones and to check the gallbladder wall. In a nuclear medicine test, called HIDA scan or cholescintigraphy, radioactive dye is injected 7) ___ intravenously and is secreted into the bile. Cholecystitis is likely if the scan shows bile doesn’t make it from the liver into the gallbladder.
Using a flexible tube inserted through the mouth, through the stomach, and into the small intestine, a doctor can see through the tube and inject dye into the bile system ducts. Tiny surgical tools can be used to treat some gallstone conditions during ERCP. ERCP stands for: Endoscopic Retrograde Cholangiopancreatography. Magnetic resonance cholangiopancreatography (MRCP) is also a good diagnostic tool: An MRI scanner provides high-resolution images of the bile ducts, pancreas, and gallbladder. MRCP images help guide further tests and treatments. Endoscopic ultrasound is another helpful diagnostic, in which a tiny ultrasound 8) ___ probe on the end of a flexible tube is inserted through the mouth to the intestines. Endoscopic ultrasound can help detect choledocholithiasis and gallstone pancreatitis. Although they may be used to look for other problems in the abdomen, X-rays generally cannot diagnose gallbladder disease. However, X-rays may be able to detect gallstones.
During gallbladder surgery (cholecystectomy), a surgeon removes the gallbladder, using either laparoscopy (several small cuts) or laparotomy (traditional “open“ surgery with a larger incision). Infection may be present during cholecystitis. Though antibiotics don’t typically cure cholecystitis, they can prevent an 9) ___infection from spreading. After surgery for gallbladder cancer, chemotherapy and radiation may be used to help prevent cancer from returning. An oral medication, ursodeoxycholic acid is for people with problems from gallstones who are not good candidates for 10) ___surgery, this oral medicine is an option. Ursodeoxycholic acid may help dissolve small cholesterol gallstones and reduce symptoms. Another oral solution is called Chenix.
In a procedure called, extracorporeal shock-wave lithotripsy: High-energy shockwaves are projected from a machine through the abdominal wall, breaking up gallstones. Lithotripsy works best if only a few small gallstones are present. In a procedure called, contact solvent dissolution: a needle is inserted through the skin into the gallbladder, and chemicals are injected that dissolve gallstones. This technique is rarely used.
Sources: WebMD.com; MayoClinic.org; Wikipedia
ANSWERS: 1) liver; 2) bile; 3) gallstones; 4) inflammation; 5) cancer; 6) ultrasound; 7) intravenously; 8) probe; 9) infection; 10) surgery
A Glimpse into the Disease and Trauma of Andy Warhol’s Life
Andy Warhol (1928-1987) in 1975. Source: Mondadori Publishers, gettyimages.co.uk, Public Domain, Wikimedia Commons
Retired Seattle surgeon and medical historian, John A. Ryan Jr. with his wife, Jody
Though Andy Warhol’s death has been associated with routine gallbladder surgery over the past three decades, one medical expert is saying that the legendary pop artist’s death shouldn’t be considered such a shock. “This was major, major surgery – not routine – in a very sick person,“ medical historian and retired surgeon Dr. John Ryan told The New York Times in a recent phone interview. Ryan, is the meritus chief of surgery at Virginia Mason Hospital in Seattle, Washington, and has been spending the past four years since his retirement studying Warhol’s medical history. Warhol’s family had a history of gallbladder issues, and Warhol himself had been very ill for at least a month before his death. However, his fear of hospitals combined with his hefty workload made him put his health on the back-burner.
In terms of Warhol’s early health: in third grade, he had Sydenham’s chorea (also known as St. Vitus’ Dance), the nervous system disease that causes involuntary movements of the extremities, which is believed to be a complication of scarlet fever which causes skin pigmentation blotchiness. Often bedridden as a child, he became an outcast at school and bonded with his mother. At times when he was confined to bed, he drew, listened to the radio and collected pictures of movie stars around his bed. Warhol later described this period as very important in the development of his personality, skill-set and preferences. After graduating from high school, his intentions were to study art education at the University of Pittsburgh in the hope of becoming an art teacher, but his plans changed and he enrolled in the Carnegie Institute of Technology in Pittsburgh, where he studied commercial art.
Warhol went in for a seemingly simple gallbladder operation in 1987 but ended up dying just 12 hours later – shocking the nation. But now, Dr. Ryan says we should have seen the icon’s death coming. According to Dr. Ryan, who presented his findings, last week at the annual meeting of the Pacific Coast Surgical Association, Warhol’s death should not have come as such a surprise. Looking at the pop artist’s medical history, Dr Ryan discovered that Warhol had almost 15 years of gallbladder trouble and a family history of it as well. Warhol’s father had his gallbladder removed in 1928, the same year his son was born. Warhol had been sick for at least a month before his death, although he had attempted to hide it. His fear of hospitals was another factor in his lack of receiving any serious treatment. The revered artist had a fear of hospitals which had delayed his ability to receive serious treatment. Further medical records research showed Dr Ryan that Warhol was dehydrated and gaunt from having barely eaten in the previous month. Additionally, Warhol had been taking speed daily for years. And he was still feeling the effects of a brush with death in 1968 after he was shot by Valerie Solanas, a radical feminist writer. At that time, he had been declared dead in the emergency room and had nine damaged organs – Warhol’s surgeon gave even odds on the artist lasting the night. His recovery left him with a lifetime of trouble with eating and swallowing, as well as a split in his abdominal muscles that gave him a large hernia. After he survived the gunshot wounds, for the rest of his life, Warhol had to wear a special truss or corset to hold his innards together.
So in 1987, on top of the gallbladder removal, and repair to his stomach wall, according to reports, the operation seemed to go well, and Warhol was in his room making calls that evening. A private nurse who went to check on him at 4am said he still seemed fine. But about two hours later, Warhol was found blue and unresponsive, and resuscitation efforts failed. An autopsy concluded that �ventricular fibrillation’ was the cause of death, meaning that Warhol’s heart had quivered and stopped. Stewart Redmond Walsh, a professor of vascular surgery at the National University of Ireland, Galway, has researched sudden death after surgery, and says it’s more common than we think. He explained that when a sick body goes through the trauma of a major surgery, the entire body feels the stress, not just the organ being operated on, which can be fatal. When Dr Ryan entered the data from Warhol’s case into the new Surgical Risk Calculator of the American College of Surgeons, it put such a patient’s chance of dying at 4.2 percent.
Andy Warhol suffered from many health problems throughout his life
Andy Warhol’s family suffered from a history of gallbladder illness. In 1928, his father Orenja, had his gallbladder removed. And less than 12 hours after a routine gallbladder removal, Warhol passed away from complications.
At the age of eight, Warhol came down with a rare disease known as chorea, or St. Vitus’ dance, characterized by involuntary movement, disturbed gait, grimacing, and hypotonia, or abnormally low muscle tone. Originally, Warhol was diagnosed with rheumatic fever. At the time, before antibiotics, approximately 10 percent of cases of rheumatic fever worsened and became chorea. Warhol stayed in bed for about ten weeks. When he finally returned to school, he had a relapse of the illness on the first day and returned to bed.
Blotchy skin is a common symptom of chorea. By the time Warhol became famous, in the early 1960s, the blotches had gone away, but they marked his face in adolescence and early adulthood, and he had bad skin his entire life. He wrote: �I had another skin problem, too – I lost all my pigment when I was eight years old. Another name people used to call me was “Spot“.
Warhol also had a huge drug problem. His New York City studio, the Factory was the hip hangout for amphetamine (speed) users. In particular, Warhol was addicted to Obetrol, marketed today as Adderall, a fairly common drug used to treat ADHD. He took a daily dose throughout his life.
In June 1968, he was shot at close range by Valerie Solanas, a radical feminist writer. For the rest of his life he wore a corset that held his bowels together where his ruined abdominal muscles could no longer.
He also worried about �catching’ cancer, his fluctuating weight, colds that he was convinced presaged pneumonia, about brain tumors and strokes, blood pressure and blackouts. In the last years of his life, Warhol worried most about AIDS, and carefully avoided those (even close friends or ex-lovers) whom he knew to be suffering from the �magic disease’.
Sources: NY Times, Wikipedia, DailyMail.uk.com;
Experimental PFSPZ Malaria Vaccine Provides Durable Protection Against Multiple Strains
Malaria is transmitted to humans through the bite of infected mosquitoes, which inject immature malaria parasites called sporozoites into a person’s bloodstream. The parasites travel to the liver, where they mature, multiply and spread via the bloodstream throughout the body causing malaria symptoms including chills, fever, headache, nausea, sweating and fatigue. According to the World Health Organization, 214 million people were infected with malaria globally in 2015 and 438,000 people died, mostly young African children. The species Plasmodium falciparum is the most common cause of malaria morbidity and mortality in Africa. In the United States, travel-related malaria is a concern for international tourists, aid workers and military personnel worldwide.
According to an article published in the Proceedings of the National Academy of Sciences (PNAS; 21 Feb 2017), an investigational malaria vaccine has protected a small number of healthy U.S. adults from infection with a malaria strain different from that contained in the vaccine. The National Institute of Allergy and Infectious Diseases (NIAID), part of the National Institutes of Health, sponsored and co-conducted the Phase 1 clinical trial.
The PfSPZ Vaccine used in this study was developed by Sanaria Inc., of Rockville, Maryland. The vaccine contains weakened P. falciparum sporozoites that do not cause infection but are able to generate a protective immune response against live malaria infection. Earlier research at the NIH Clinical Center with the PfSPZ Vaccine found it to be safe, well-tolerated and protective for more than a year when tested in healthy U.S. adults against a single Africa-derived malaria strain matched to the PfSPZ Vaccine. The study enrolled 31 healthy adults ages 18 to 45 years and each study subject was assigned to receive three doses of the PfSPZ Vaccine at eight-week intervals by rapid intravenous injection. Nineteen weeks after receiving the final dose of the test vaccine, participants who received the vaccine and a group of non-vaccinated volunteers were exposed in a controlled setting to bites from mosquitoes infected with the same strain of P. falciparum parasites (NF54, from Africa) that were used to manufacture PfSPZ Vaccine. Results showed that 9 of the 14 participants (64%) who received PfSPZ Vaccine demonstrated no evidence of malaria parasites, while all 6 of the non-vaccinated participants who were challenged at the same time had malaria parasites in their blood. Of the 9 participants who showed no evidence of malaria, six participants were again exposed in a controlled setting to mosquito bites, this time from mosquitoes infected with a different strain of P. falciparum parasite, 33 weeks after the final immunization. In this group, 5 of the 6 participants (83%) were protected against malaria infection, while again, none of the 6 participants who did not receive the vaccine and were challenged were protected. All participants who became infected with malaria immediately received medical treatment.
The authors also found that the PfSPZ Vaccine activated T cells, a key component of the body’s defenses against malaria, and induced antibody responses in all vaccine recipients. Vaccine-specific T-cell responses were comparable when measured against both of the malaria challenge strains, providing some insights into how the vaccine was mediating protection.
Ongoing research will determine whether protective efficacy can be improved by changes to the PfSPZ Vaccine dose and number of immunizations. Accordingly, a Phase 2 efficacy trial testing three different dosages in a three-dose vaccine regimen is now underway in 5-to 12-month-old infants in Western Kenya to assess safety and efficacy against natural infection.
Sanaria Inc., designed, manufactured, and provided PfSPZ Vaccine and the heterologous challenge mosquitoes. NIAID supported the development of the experimental vaccine through several Small Business Innovation Research grants.
Survival Rate May Be Improving for Extremely Preterm Infants
Data reported during the past 5 years indicate that rates of survival have increased among infants born at the borderline of viability, but less is known about how increased rates of survival among these infants relate to early childhood neurodevelopmental outcomes. A study appearing in the New England Journal of Medicine (2017; 376:617-628) has shown that very early preterm infants are more likely to survive than in previous years, and the survivors are less likely to have neurological problems. The study found that of the more than 4,000 infants born at 11 sites within the network from 2000 to 2011, survival rates increased from 30% to 36%, and the proportion of survivors who did not have a neurological or developmental impairment increased from 16% to 20%. The authors theorize that these improvements are a result of advances in the care provided to expectant mothers and their newborns.
Infants in the study were born between the 22nd and 24th week of pregnancy, far earlier than the 40 weeks generally expected for a pregnancy to reach term. Those born from 2008 to 2011 had the lowest death rate (64%). From 2004 to 2007, the death rate was 70%, unchanged from 2000 to 2003.
According to the authors, the results encompass trends for a large number of infants at multiple research sites, but they should not be used to predict the outcome for an individual child. In addition, providing care to infants born so early is often challenging. Physicians and family members can be reluctant to expose an infant to sometimes painful life-support procedures. Those offered active treatment may survive, but may have hearing loss, blindness, cerebral palsy, and severe intellectual disability. The authors added that in the past, many experts had feared that advances leading to improvements in survival among extremely preterm infants might also result in a higher proportion of infants with disabilities. However, in the current study, it was found that across all three time intervals, the percentage of infants who survived with a disability did not change significantly. Finally, the authors wrote that the increases in overall survival and survival without neurological harm likely result from improvements in the care given to mothers and newborns. One potential contributing factor is the wider use of antenatal steroids. These drugs, which are given to women at risk for preterm birth, help the infant’s lungs mature, leaving the infant less reliant on ventilation therapy, which can sometimes damage the lungs and lead to infections.
FDA Clears Test To Identify Organisms that Cause Bloodstream Infections and Provide Antibiotic Sensitivity Results
Bacterial or yeast blood infections can occur in patients of all ages, but are particularly severe in infants, the elderly and those with weakened immune systems. If not treated rapidly, such bloodstream infections can lead to severe complications, such as septic shock and death.
The FDA has marketing clearance of the PhenoTest BC Kit, performed on the Pheno System. This is the first test to identify organisms that cause bloodstream infections and provide information about which antibiotics the organism is likely to respond to (antibiotic sensitivity). The test also reduces the amount of time it takes to provide this important information, which can guide antibiotic treatment recommendations more quickly. Unlike traditional identification and antibiotic susceptibility tests that may take 24 to 48 hours after detection in a positive blood culture to provide test results, the PhenoTest BC Kit can identify bacteria or yeast from a positive blood culture in approximately 1.5 hours. For certain organisms, the test also provides important information to guide treatment recommendations in approximately 6.5 hours after the organisms are detected from blood cultures.
The test can identify 14 different species of bacteria and two species of yeast that cause bloodstream infections, while also providing antibiotic sensitivity information on 18 selected antibiotics for a subset of the identified organisms as appropriate. The test can also identify the presence of two indicators of antibiotic resistance, which can occur when potentially harmful bacteria change in a way that reduces or eliminates the effectiveness of antibiotics.
The PhenoTest BC Kit works by measuring the similarity of the infection-causing organism’s genetic material to DNA known to be unique to specific bacteria or yeast. Once the organism is identified, it is mixed with antibiotics and the growth of the bacteria is measured by time-lapse images. If the organism does not grow when the antibiotic is present, this means that an antibiotic can possibly be used for treatment. The FDA reviewed the data for the PhenoTest BC Kit through the de novo premarket review pathway, a regulatory pathway for devices of a new type with low-to-moderate-risk that are not substantially equivalent to an already legally marketed device and for which special controls can be developed, in addition to general controls, to provide a reasonable assurance of safety and effectiveness of the devices. The FDA’s decision to allow marketing was based largely on its review of the sponsor’s primary clinical study of 1,850 positive blood cultures. In this study, the PhenoTest BC Kit provided correct identification of the bacteria or yeast in the positive blood culture more than 95% of the time. Results for testing whether the bacteria were sensitive to antibiotics were also accurate when compared to traditional tests.
Risks associated with use of the PhenoTest BC Kit include false positive findings, which can occur when an individual not infected with organisms that cause bloodstream infections receives a test result that incorrectly indicates that he or she is infected. Results obtained from the test should always be interpreted alongside additional laboratory test results. The PhenoTest BC Kit and the Pheno System are manufactured by Accelerate Diagnostics Inc. in Tucson, Arizona.
Kale and Pecorino Salad with Walnuts & Sherry-Soaked Raisins
I am always thinking about kale because our family is focused on health, although we sometimes break away for something sweet. Kale is one of those super healthy foods so I have experimented with many combos of ingredients with kale. © Joyce Hays, Target Health Inc.
1 cup walnut halves and/or pieces, toasted
1/2 cup golden raisins
2 Tablespoons white wine vinegar or champagne vinegar
1 Tablespoon creme sherry
1 Tablespoon water
1/2 cup Panko crumbs
2 or more (optional) cloves garlic, pressed
Pinch kosher salt (optional)
Pinch black pepper
Pinch chili flakes
1 teaspoon curry powder
4 Tablespoons olive oil
1 bunch Tuscan kale washed and patted dry
2 oz. or 1/2 cup pecorino cheese, grated or ground in a food processor
Zest of 1/2 lemon
Juice of 1/2 lemon
Prepare the walnuts:
Heat oven to 350 degrees. Toast walnuts on a baking sheet for 10 minutes, tossing once. Let cool and coarsely chop.
Prepare the raisins:
In a small saucepan over low heat, simmer champagne vinegar, water, creme sherry and raisins for 5 minutes, until plump and soft. Set aside in liquid, for as long as you can. (Keep in the liquid)
Prepare the crumbs:
Toast panko, garlic, curry powder, pinches, pepper, chili flakes and 2 teaspoons of the olive oil in a skillet together with a pinch of salt until golden. Set aside.
Prepare the kale:
1. Trim heavy stems off kale and remove ribs. Stack sections of leaves and roll them into a tube, then cut them into very thin ribbons crosswise.
2. Put kale in a large salad bowl. Add the pecorino, walnuts and raisins (leaving any leftover vinegar mixture in dish), remaining 2 Tablespoons olive oil and lemon juice and toss until all the kale ribbons are coated. Taste and adjust seasonings with salt, pepper and some of the reserved vinegar mixture from the raisins, if needed. Let sit for 10 minutes before serving, if you can. This enables all of the lovely flavors to merge.
3. Add the Panko crumbs, just before you serve the salad, and toss it one more time.
We started with chilled Orvieto, warm Italian bread, olive oil & butter and an antipasto.
Next the kale salad with fresh halibut dipped in egg then panko (mixed with curry and parmesan), and quickly cooked in a small amount of olive oil. For dessert we had spears of fresh mango which we have been eating all week.
This weekend we went to MetOpera and saw, Rusalka an opera by Antonin Dvorak. We love Dvorak, so were looking forward to this. The role of Rusalka was sung by the Latvian soprano, Kristine Opolais; the role of the Prince was sung by (beautiful) tenor, Brandon Jovanovich from Montana.
Below are my two favorite Dvorak compositions; the first is the hauntingly gorgeous First Act aria, Song to the Moon from Rusalka; the second is his magnificent, String Quartet #12 (American). I’m including one other video, which is a cello rendition of Song to the Moon The cellist is the young, Stjepan Hauser, from Croatia.
A glass of icy Proseco. Joyce Hays, Target Health Inc.
February 22, 2017
University of Wisconsin-Madison
Plumbing a 90 million-year-old layer cake of sedimentary rock in Colorado, a team of scientists has found evidence confirming a critical theory of how the planets in our solar system behave in their orbits around the sun. The finding is important because it provides the first hard proof for what scientists call the ”chaotic solar system.’
Plumbing a 90 million-year-old layer cake of sedimentary rock in Colorado, a team of scientists from the University of Wisconsin-Madison and Northwestern University has found evidence confirming a critical theory of how the planets in our solar system behave in their orbits around the sun.
The finding, published Feb. 23, 2017 in the journal Nature, is important because it provides the first hard proof for what scientists call the “chaotic solar system,” a theory proposed in 1989 to account for small variations in the present conditions of the solar system. The variations, playing out over many millions of years, produce big changes in our planet’s climate — changes that can be reflected in the rocks that record Earth’s history.
The discovery promises not only a better understanding of the mechanics of the solar system, but also a more precise measuring stick for geologic time. Moreover, it offers a better understanding of the link between orbital variations and climate change over geologic time scales.
Using evidence from alternating layers of limestone and shale laid down over millions of years in a shallow North American seaway at the time dinosaurs held sway on Earth, the team led by UW-Madison Professor of Geoscience Stephen Meyers and Northwestern University Professor of Earth and Planetary Sciences Brad Sageman discovered the 87 million-year-old signature of a “resonance transition” between Mars and Earth. A resonance transition is the consequence of the “butterfly effect” in chaos theory. It plays on the idea that small changes in the initial conditions of a nonlinear system can have large effects over time.
In the context of the solar system, the phenomenon occurs when two orbiting bodies periodically tug at one another, as occurs when a planet in its track around the sun passes in relative proximity to another planet in its own orbit. These small but regular ticks in a planet’s orbit can exert big changes on the location and orientation of a planet on its axis relative to the sun and, accordingly, change the amount of solar radiation a planet receives over a given area. Where and how much solar radiation a planet gets is a key driver of climate.
“The impact of astronomical cycles on climate can be quite large,” explains Meyers, noting as an example the pacing of Earth’s ice ages, which have been reliably matched to periodic changes in the shape of Earth’s orbit, and the tilt of our planet on its axis. “Astronomical theory permits a very detailed evaluation of past climate events that may provide an analog for future climate.”
To find the signature of a resonance transition, Meyers, Sageman and UW-Madison graduate student Chao Ma, whose dissertation work this comprises, looked to the geologic record in what is known as the Niobrara Formation in Colorado. The formation was laid down layer by layer over tens of millions of years as sediment was deposited on the bottom of a vast seaway known as the Cretaceous Western Interior Seaway. The shallow ocean stretched from what is now the Arctic Ocean to the Gulf of Mexico, separating the eastern and western portions of North America.
“The Niobrara Formation exhibits pronounced rhythmic rock layering due to changes in the relative abundance of clay and calcium carbonate,” notes Meyers, an authority on astrochronology, which utilizes astronomical cycles to measure geologic time. “The source of the clay (laid down as shale) is from weathering of the land surface and the influx of clay to the seaway via rivers. The source of the calcium carbonate (limestone) is the shells of organisms, mostly microscopic, that lived in the water column.”
Meyers explains that while the link between climate change and sedimentation can be complex, the basic idea is simple: “Climate change influences the relative delivery of clay versus calcium carbonate, recording the astronomical signal in the process. For example, imagine a very warm and wet climate state that pumps clay into the seaway via rivers, producing a clay-rich rock or shale, alternating with a drier and cooler climate state which pumps less clay into the seaway and produces a calcium carbonate-rich rock or limestone.”
The new study was supported by grants from the National Science Foundation. It builds on a meticulous stratigraphic record and important astrochronologic studies of the Niobrara Formation, the latter conducted in the dissertation work of Robert Locklair, a former student of Sageman’s at Northwestern.
Dating of the Mars-Earth resonance transition found by Ma, Meyers and Sageman was confirmed by radioisotopic dating, a method for dating the absolute ages of rocks using known rates of radioactive decay of elements in the rocks. In recent years, major advances in the accuracy and precision of radioisotopic dating, devised by UW-Madison geoscience Professor Bradley Singer and others, have been introduced and contribute to the dating of the resonance transition.
The motions of the planets around the sun has been a subject of deep scientific interest since the advent of the heliocentric theory — the idea that Earth and planets revolve around the sun — in the 16th century. From the 18th century, the dominant view of the solar system was that the planets orbited the sun like clockwork, having quasiperiodic and highly predictable orbits. In 1988, however, numerical calculations of the outer planets showed Pluto’s orbit to be “chaotic” and the idea of a chaotic solar system was proposed in 1989 by astronomer Jacques Laskar, now at the Paris Observatory.
Following Laskar’s proposal of a chaotic solar system, scientists have been looking in earnest for definitive evidence that would support the idea, says Meyers.
“Other studies have suggested the presence of chaos based on geologic data,” says Meyers. “But this is the first unambiguous evidence, made possible by the availability of high-quality, radioisotopic dates and the strong astronomical signal preserved in the rocks.”
- Chao Ma, Stephen R. Meyers, Bradley B. Sageman. Theory of chaotic orbital variations confirmed by Cretaceous geological evidence. Nature, 2017; 542 (7642): 468 DOI: 10.1038/nature21402
Source: University of Wisconsin-Madison. “From rocks in Colorado, evidence of a ‘chaotic solar system’.” ScienceDaily. ScienceDaily, 22 February 2017. <www.sciencedaily.com/releases/2017/02/170222131512.htm>.
February 22, 2017
Tokyo Institute of Technology
Scientists at the Earth-Life Science Institute at the Tokyo Institute of Technology report in Nature (Fen. 22, 2017) unexpected discoveries about the Earth’s core. The findings include insights into the source of energy driving the Earth’s magnetic field, factors governing the cooling of the core and its chemical composition, and conditions that existed during the formation of the Earth.
The Earth’s core consists mostly of a huge ball of liquid metal lying at 3000 km beneath its surface, surrounded by a mantle of hot rock. Notably, at such great depths, both the core and mantle are subject to extremely high pressures and temperatures. Furthermore, research indicates that the slow creeping flow of hot buoyant rocks — moving several centimeters per year — carries heat away from the core to the surface, resulting in a very gradual cooling of the core over geological time. However, the degree to which the Earth’s core has cooled since its formation is an area of intense debate amongst Earth scientists.
In 2013 Kei Hirose, now Director of the Earth-Life Science Institute (ELSI) at the Tokyo Institute of Technology (Tokyo Tech), reported that the Earth’s core may have cooled by as much as 1000 degrees Celsius since its formation 4.5 billion years ago. This large amount of cooling would be necessary to sustain the geomagnetic field, unless there was another as yet undiscovered source of energy. These results were a major surprise to the deep Earth community, and created what Peter Olson of Johns Hopkins University referred to as, “the New Core Heat Paradox,” in an article published in Science.
Core cooling and energy sources for the geomagnetic field were not the only difficult issues faced by the team. Another unresolved matter was uncertainty about the chemical composition of the core. “The core is mostly iron and some nickel, but also contains about 10% of light alloys such as silicon, oxygen, sulfur, carbon, hydrogen, and other compounds,” Hirose, lead author of the new study to be published in the journal Nature. “We think that many alloys are simultaneously present, but we don’t know the proportion of each candidate element.”
Now, in this latest research carried out in Hirose’s lab at ELSI, the scientists used precision cut diamonds to squeeze tiny dust-sized samples to the same pressures that exist at the Earth’s core. The high temperatures at the interior of the Earth were created by heating samples with a laser beam. By performing experiments with a range of probable alloy compositions under a variety of conditions, Hirose’s and colleagues are trying to identify the unique behavior of different alloy combinations that match the distinct environment that exists at the Earth’s core.
The search of alloys began to yield useful results when Hirose and his collaborators began mixing more than one alloy. “In the past, most research on iron alloys in the core has focused only on the iron and a single alloy,” says Hirose. “But in these experiments we decided to combine two different alloys containing silicon and oxygen, which we strongly believe exist in the core.”
The researchers were surprised to find that when they examined the samples in an electron microscope, the small amounts of silicon and oxygen in the starting sample had combined together to form silicon dioxide crystals — the same composition as the mineral quartz found at the surface of the Earth.
“This result proved important for understanding the energetics and evolution of the core,” says John Hernlund of ELSI, a co-author of the study. “We were excited because our calculations showed that crystallization of silicon dioxide crystals from the core could provide an immense new energy source for powering the Earth’s magnetic field.” The additional boost it provides is plenty enough to solve Olson’s paradox.
The team has also explored the implications of these results for the formation of the Earth and conditions in the early Solar System. Crystallization changes the composition of the core by removing dissolved silicon and oxygen gradually over time. Eventually the process of crystallization will stop when then core runs out of its ancient inventory of either silicon or oxygen.
“Even if you have silicon present, you can’t make silicon dioxide crystals without also having some oxygen available,” says ELSI scientist George Helffrich, who modeled the crystallization process for this study. “But this gives us clues about the original concentration of oxygen and silicon in the core, because only some silicon:oxygen ratios are compatible with this model.”
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- Kei Hirose, Guillaume Morard, Ryosuke Sinmyo, Koichio Umemoto, John Hernlund, George Helffrich, Stéphane Labrosse. Crystallization of silicon dioxide and compositional evolution of the Earth’s core. Nature, 2017; DOI: 10.1038/nature21367
Source: Tokyo Institute of Technology. “‘Quartz’ crystals at Earth’s core power its magnetic field.” ScienceDaily. ScienceDaily, 22 February 2017. <www.sciencedaily.com/releases/2017/02/170222131505.htm>.