Expectation may be essential to memory formation

 

Credit: Human Brain Project

A theory that links memory encoding to expectations of future relevance may better explain how human memory works, according to a team of Penn State psychologists.

Modern psychology posits two major theories to explain the mechanisms of how memories are formed. The first is object-based encoding, storing all information about an object in working memory. The second is feature-based encoding, selectively remembering aspects of an object. For example, if you watch a group of people playing basketball, under object-based encoding theory, the brain remembers all aspects of the ball. In feature-based encoding, the brain remembers that it saw a ball, but may have no recollection of the color if the color of the ball is an unnecessary feature according to the task at hand.

The proposed theory, expectancy-based binding, suggests that subjects can remember features presented in a visual scene or movie without necessarily remembering which object went with which feature when it is not necessary to do so.

"The key discovery was that attending an object for an extended period of time does not ensure that all of the features of that object will be correctly associated with it in memory," said Brad Wyble, assistant professor of psychology.

The researchers tested 60 participants and asked them to watch videos in which two balls were thrown between multiple people. The first ball thrown was the target ball. Participants counted the number of times the ball was passed. The second ball was the distractor ball. Each participant watched 36 trials, recording their counts of the target ball after each. The balls in each video were red, green, blue or purple. The researchers reported their results in a recent issue of Cognition.

For the first 31 trials, participants chose only the number of passes made with the target ball. After the thirty-second trial, a message popped up on the participant's screen that read, "This is a surprise memory test! Here we test the 'Color' of the target ball. Press a corresponding number to indicate the 'Color' of the target ball."

To this question, 37 percent of participants—22 of 60—responded with the incorrect color of the ball, and 16 of these 22 incorrect responses selected the color of the distractor ball.

"Participants have memories of the color of both balls, but those memories aren't attached specifically to the target ball or the distractor ball," said Hui Chen, post-doctoral fellow in psychology and first author.

It is statistically significant that 73 percent of participants responded with the color of the distractor ball. If participants had no memory of the color of the balls seen in the video, as feature-based encoding might suggest, then participants would have chosen the distractor ball only 33 percent of the time when they could not remember the target ball's color.

Four control trials, in which participants reported the color of the target ball and number of times the target ball was passed, followed the trial containing the surprise question. For these trials, the response error was once again lower. Only 14 percent of participants responded incorrectly in the control trials, as compared to 37 percent in the surprise trial.

"What we're showing is that attention is not enough to ensure accurate memory," said Wyble. "You need some kind of expectation that attributing certain features to the object is important."

This indicates that much of what a person can remember is based on their expectation of the information they will need to recall. Once participants realized they would need to report the color of the ball, they were able to do so with high accuracy.

To ensure the results were robust, the entire experiment was repeated a second time with a new group of participants. The new experiment replicated the results of the previous experiment, which provides additional confidence that these surprising memory failures are a genuine effect.

कपाल झर्न नदिन के गर्ने, के गर्दै नगर्ने ?

कपाल झर्ने समस्या अहिले आम बनेको छ । युवा अवस्थामै कपाल झरेर बुढ्यौलीको महशुस गर्दै तनाव लिनेहरु थुप्रै छन् । त्यसैले कपाल झरिसकेपछि उमार्न अनेक उृपाय लगाउनुभन्दा झर्न नदिने निम्न उपाय अपनाउन सकिन्छ ।

– नुहाएपछि टाउकोमा घ्युकुमारी दल्ने र १५ मिनटपछि धुने । यसो गर्नाले पनि कपाल झर्ने क्रम रोकिन्छ । सातामा तीनपटक यस्तो गरेमा चाँडै सुधार देख्न पाइन्छ ।
– पानीमा नीमको पात हालेर पानी आधा नसुकुञ्जेल उमाल्ने र यसरी उमालेको पानी सेलाएपछि कपाल धुनाले कपाल बलियो हुन्छ । नीमपानीले नुहाउँदा पानी आँखामा नपरोस् भन्नेमा ध्यान दिनुपर्छ ।
– सुकेको अमला तोरी अथवा नरिवलको तेलमा केही बेर भिजाइ मसाज गर्दा कपाल बलियो हुन्छ ।
– राति मेथी भिजाउने, बिहान यसलाई राम्रोसँग पिस्ने र कपालको जरासम्म लाग्नेगरी टाउकोमा दल्ने । ४० मिनेटपछि कपाल धुने । यसो गर्दा कपाल झर्ने क्रम रोकिन्छ ।
– प्याज पिसेर यसको रस निकाल्ने, त्यसमा रुवा चोपेर कपालको टुप्पोदेखि फेदसम्म लाग्नेगरी दल्ने र ४० मिनेटपछि धुनाले कपाल झर्न रोकिन्छ ।
– ग्रीन टीको दुईवटा ब्याग तीन कप तातो पानीमा डुबाउने र यसलाई नसेलाइञ्जेलसम्म त्यसै छोडिदिने । त्यसपछि सेलाएको पानीले कपाल धुने अथवा मसाज गर्ने । यसो गर्दा कपाल बलियो हुन्छ ।
– अण्डाको पहेँलो भाग हटाइ सेतो भाग कपालको जरासम्म पुग्नेगरी टाउकोमा दल्ने र २० मिनेटपछि नुहाउने । अण्डामा रहेको प्रोटिन, भिटामिनले कपाल झर्ने क्रम रोक्छ ।
– कपाल बढी नै झर्ने गरेको छ भने सातामा पाँच दिन करिब ३० मिनेटका हिसाबले व्यायाम गर्नुपर्छ । व्यायाम गर्दा टाउकाको रक्तसञ्चार तीव्र भई अक्सिजन पुग्छ र कपाल कमजोर हुन पाउँदैन ।
– कपाल झर्ने समस्या भएकाले प्रोटिन, आइरन, जिंक, सल्फर, भिटामिन–सी, भिटामिन–बी युक्त खानामा जोड दिनुपर्छ । यसले कपाललाई बलियो बनाउँछ ।
– समयसमयमा कपालमा मेहदी लगाउनाले  पनि कपाल बलियो हुन्छ ।
– कपाल बलियो बनाउन र झर्न नदिन सातामा दुईपटक कपालमा अमला, बदाम, जैतुन, नरिवल, तोरीको तेल लगाउनुपर्छ ।

के नगर्ने ?
– कपाल झर्ने समस्या भएकाले कपाल कसेर बाँध्नु हुँदैन ।
– कपाल भर्ने समस्या छ भने कपाल कोरिरहनु हुँदैन । यसो गर्दा कपाल झर्ने क्रम बढ्न जान्छ ।
– कपाल झर्ने समस्या छ भने घाममा धेरै हिँड्डुल गर्नु हुँदैन । घाममा निस्किँदा छाता बोक्नुपर्छ ।
– कपाल बढी नै झर्ने गरेको छ भने बढी तातो पानीले नुहाउनु हुँदैन ।
– कपाल नझरोस् भन्ने चाहनेले कपाल रंगाउने, स्ट्रेट गर्नु हुँदैन । कपाललाई प्राकृतिक अवस्थामै रहन दिनुपर्छ ।
– कपाल भर्ने समस्या भएकाले नुहाएपछि कपाल जोडसँग पुछ्नु हुँदैन ।
– कपाल झर्ने समस्या छ भने रातो मासु कम खानुपर्छ ।
– फर्सीको बियाँ (सुकाएको), बन्दा, ब्रोकाउली, काउली, दाल आदि बढी खानुपर्छ ।
– जंक फुडमा क्यालोरीको मात्रामात्रै उच्च  हुने र अन्य पोषक तत्व नहुने भएकाले यसले कपाल थप झार्न सक्छ

Innovative collaboration leads to improved discharge outcomes for children with asthma

A new study demonstrates that pediatric patients with asthma who left the hospital with their prescription medications made fewer emergency department (ED) visits after they were discharged than if they were discharged still needing to go to a pharmacy to pick-up their medications. Led by physicians and pharmacists at Boston Medical Center (BMC) and highlighted in this month's issue of Pediatrics, "Meds-in-Hand" helps simplify the lives of patients and families and provides them the opportunity to learn more about how to properly use the medications from the doctors, nurses, and pharmacists who know them best.

Asthma is a common childhood disease affecting some 235 million children worldwide, according to the World Health Organization. It is also the second most costly chronic disease in children in the U.S. A significant portion of the cost - ED visits and admissions - may be avoidable if patients had better access to their prescriptions.

Led by Jonathan Hatoun, MD, MPH, formerly of BMC's department of pediatrics, and James Moses, MD, MPH, a pediatrician and associate chief quality officer at BMC, the group had determined that as many as 37 percent of BMC pediatric patients did not get their prescriptions filled in a timely manner after being discharged for an asthma exacerbation. Recognizing that this was an opportunity to improve care, a team of pediatricians and pharmacists worked together to remove barriers to picking up prescriptions. Barriers include patients and families not having transportation to the local pharmacy, finding time to get to the pharmacy, and having active insurance.

After making improvements in the discharge process for two years, the team reliably discharged 75 percent of patients with "Meds in Hand," meaning the patients had all their medications and did not have to go to a pharmacy after being discharged. The team was able to achieve this success by implementing an in-room delivery service on the day of discharge, eliminating the need to fill prescriptions at another pharmacy. In addition, because the medication was delivered by a BMC pharmacist, patients had the opportunity to learn how to use their medications effectively while in the hospital.

Importantly, this led to a significant reduction in the odds of an ED visit in the 30 days after discharge. Patients discharged with their medications also were more likely to refill their prescriptions.

"While our study was small, it shows that a fairly simple intervention can be administered by the inpatient team to help decrease future ED visits for patients with asthma" Hatoun said, adding "we might expect similar results for other diseases, though more studies need to be done."

Provided by Boston University Medical Center

Anti-inflammatory drug may prevent rapid aging in people with HIV

Anti-inflammatory drug may prevent rapid aging in people with HIV
Shokrollah Elahi is lead author of a study that show an anti-inflammatory drug may prevent accelerated aging in HIV-infected individuals.
New research from the University of Alberta's School of Dentistry shows that a commonly used cholesterol-lowering drug could help people with HIV live longer and enjoy an improved quality of life.

The study, Atorvastatin restricts HIV replication in CD4+ T cells by upregulation of p21, published in AIDS (the official journal of the International AIDS Society), shows that the anti-inflammatory drug atorvastatin (Lipitor) may prevent rapid aging associated with the disease.

"HIV-infected individuals experience accelerated aging in different organs as the results of chronic inflammation and elevated immune activation in them," says Shokrollah Elahi, lead author of the study and immunologist at the School of Dentistry. "If you reduce chronic inflammation, you can enhance their quality of life and expand their life expectancy."

With the availability of antiretroviral therapy, HIV infection has become a chronic disease. But this chronic inflammation state has been linked to rapid aging. As a result, patients now face a new set of challenges such as increased rates of cardiovascular disease, stroke, kidney and liver disease, osteoporosis, neurological disease and non-AIDS-defining malignancies, many of which are more typical of an aging population.

It has been shown that HIV-infected individuals have much higher levels of inflammation within their body than uninfected people do, despite the antiretroviral therapy.

"Human HIV infection is suppressed but not eliminated by the current medication. As a result, viral persistence in the presence of antiretroviral therapy is a major source of inflammation and substantial immune activation, both of which are linked to 'inflammaging'—a concept that contributes to the aging process in HIV-infected individuals," says Elahi. "Our study shows that cholesterol-lowering medication can reduce inflammation and makes CD4 T cells (HIV target cells) less permissible to HIV infection."

The study shows that atorvastatin—the most commonly used cholesterol-lowering medication—effectively reduces immune activation, thereby diminishing the systemic inflammation that leads to premature or accelerated aging.

Because HIV infection also causes lipid abnormalities such as high cholesterol levels in patients, HIV-infected individuals could benefit from this property of atorvastatin.

The researchers also discovered the drug reduces HIV replication by a novel mechanism, making CD4 T cells more resistant to HIV infection.

Elahi says further clinical trial studies may lead researchers to new therapeutic options to more effectively reduce the inflammation and benefit the health of HIV-infected individuals by preventing accelerated aging.

More information: Shokrollah Elahi et al. Atorvastatin restricts HIV replication in CD4+ T cells by upregulation of p21, AIDS (2016). DOI: 10.1097/QAD.0000000000000917

Provided by: University of Alberta

Marijuana smokers five times more likely to develop an alcohol problem

Adults who use marijuana are five times more likely to develop an alcohol use disorder (AUD) —alcohol abuse or dependence— compared with adults who do not use the drug. And adults who already have an alcohol use disorder and use marijuana are more likely to see the problem persist. Results of a study by researchers at Columbia University's Mailman School of Public Health and the City University of New York appear online in the journal Drug and Alcohol Dependence.

"Our results suggest that cannabis use appears to be associated with an increased vulnerability to developing an alcohol use disorder, even among those without any history of this," said Renee Goodwin, PhD, associate professor of Epidemiology at the Mailman School of Public Health. "Marijuana use also appears to increase the likelihood that an existing alcohol use disorder will continue over time."

The researchers analyzed data from 27,461 adults enrolled in the National Epidemiologic Survey on Alcohol and Related Conditions who first used marijuana at a time when they had no lifetime history of alcohol use disorders. The population was assessed at two time points. Adults who had used marijuana at the first assessment and again over the following three years (23 percent) were five times more likely to develop an alcohol use problem, compared with those who had not used marijuana (5 percent). Adult problem drinkers who did not use cannabis were significantly more likely to be in recovery from alcohol use disorders three years later.

"From a public health standpoint we recommend that further research be conducted to understand the pathways underlying these relationships as well as the degree to which various potentially vulnerable population subgroups—youth, for example—are at increased risk," noted Goodwin. "If future research confirms these findings, investigating whether preventing or delaying first use of marijuana might reduce the risk of developing alcohol use disorders among some segments of the population may be worthwhile."

Provided by Columbia University's Mailman School of Public Health

New evidence suggests Zika virus can cross placental barrier, but link with microcephaly remains unclear

Transmission electron micrograph (TEM) of Zika virus. Credit: Cynthia Goldsmith/Centers for Disease Control and PreventionZika virus has been detected in the amniotic fluid of two pregnant women whose foetuses had been diagnosed with microcephaly, according to a study published today in The Lancet Infectious Diseases. The report suggests that Zika virus can cross the placental barrier, but does not prove that the virus causes microcephaly, as more research is needed to understand the link.Researchers also analysed the whole genome of the virus found in the two pregnant women and confirmed that the virus is genetically related to the strain identified during an outbreak of Zika virus in French Polynesia in 2013."Previous studies have identified Zika virus in the saliva, breast milk and urine of mothers and their newborn babies, after having given birth. This study reports details of the Zika virus being identified directly in the amniotic fluid of a woman during her pregnancy, suggesting that the virus could cross the placental barrier and potentially infect the foetus" said Dr Ana de Filippis, lead author from the Oswaldo Cruz Institute in Rio de Janeiro, Brazil.The placental barrier is made up of layers of tissue in the placenta and regulates the exchange of substances (including infections) between the mother and foetus. The amniotic fluid is the protective liquid around the foetus.Dr de Filippis added "This study cannot determine whether the Zika virus identified in these two cases was the cause of microcephaly in the babies. Until we understand the biological mechanism linking Zika virus to microcephaly we cannot be certain that one causes the other, and further research is urgently needed."The number of reported cases of newborn babies with microcephaly in Brazil in 2015 has increased twenty-fold compared with previous years. At the same time, Brazil has reported a high number of Zika virus infections, leading to speculation that the two may be linked. Babies born with microcephaly have abnormally small heads, and are at risk of incomplete brain development. Microcephaly has previously been linked to a range of factors including genetic disorders, drug or chemical intoxication, maternal malnutrition and infections with viruses or bacteria that can cross the placental barrier such as herpes, HIV, or some mosquito borne viruses such as chikungunya.In this study, the team led by Dr de Filippis investigated the case of two women (aged 27 and 35) from Paraiba, a state in northeast Brazil. The two women presented with symptoms of Zika virus infection including fever, muscle pain and a rash during their first trimester of pregnancy. Ultrasounds taken at approximately 22 weeks of pregnancy confirmed the foetuses had microcephaly.Samples of amniotic fluid were taken at 28 weeks of pregnancy and analysed for potential infections. Both patients tested negative for dengue virus, chikungunya virus and other infections such as HIV, syphilis and herpes. Although the two women's blood and urine samples tested negative for Zika virus, their amniotic fluid tested positive for Zika virus genome and Zika antibodies. The amniotic fluid was analysed using a process called metagenomic analysis. This allows the detection of any microorganism that could be present in the samples, but only Zika virus genome was found. The RNA of the two Zika virus samples was then compared with samples from previous outbreaks, and was found to be genetically related to the strain identified in French Polynesia in 2013.Writing in a linked Comment, Professor Didier Musso from the Unit of Emerging Infectious Diseases, Institut Louis Malarde in Tahiti, French Polynesia, says: "Even if all these data strongly suggest that Zika virus can cause microcephaly, the number of microcephaly cases related to Zika virus is still unknown. The next step will be to do case-control studies to estimate the potential risk of microcephaly after Zika virus infection during pregnancy, other fetal or neonatal complications, and long-term outcomes for infected symptomatic and asymptomatic neonates." Explore further: Zika virus: Five things to knowMore information: The Lancet Infectious Diseases, www.thelancet.com/journals/laninf/article/PIIS1473-3099(16)00095-5/abstract 

What are gravitational waves? Readability Score: 7.6 What's this?

Energy from large, dramatic events in space create tiny waves that can ripple past Earth
BY CHRISTOPHER CROCKETT AND
ANDREW GRANT
This is an artist’s rendering of the gravity waves emanating from the movement of massive celestial bodies, such as two black holes.
CALTECH/MIT/LIGO LAB
Gravitational waves are ripples in the fabric of space. Throw a rock into a pond and it will create ripples — waves in the water — that appear to stretch and squeeze back again. Similarly, accelerating masses should send gravity waves into space. These ripples would cause space to stretch and squeeze back again.
On February 11, 2016, after decades of trying to directly detect such waves, scientists announced that they appear to have found them. The waves came from another galaxy far, far away. How far? Try between 750 million and 1.86 billion light-years away! There, two black holes collided, shaking the fabric of space and time, or spacetime . Here on Earth, two giant detectors in different parts of the United States quivered as gravity waves washed over them.
In his theory of general relativity, Albert Einstein predicted that ripples in spacetime should radiate energy away from enormously violent events, such as colliding stars. Such events are powerful. Still, the ripples they trigger are subtle. By the time they reach Earth, some compress spacetime by as little as the width of a proton. (A proton is one of the particles that makes up an atom.)
The newfound waves were picked up by the recently upgraded Laser Interferometer Gravitational-wave Observatory. It is now known as "advanced" LIGO. To spot a signal, LIGO uses a special mirror to split a beam of laser light. The mirror sends each beam down one of two 4-kilometer-long tubes. These tubes sit at a 90-degree angle to each other. Light ricochets back and forth 400 times down each tunnel in the detector. This turns each beam’s journey into a 1,600 kilometer (990 mile) roundtrip. Then the light recombines near its source.
The experiment was designed so that under normal conditions the light waves will cancel one another out when they recombine. When that happens, no signal moves on to a nearby detector.
But a gravity wave will stretch one tube while squeezing the other. That alters the distance the two beams travel relative to one another. Make no mistake: The difference is tiny. But it's enough that when the beams recombine, their waves no longer align perfectly align. Because they no longer cancel each other out, the detector will pick up a faint glow. This signals a passing gravity wave.
To ensure the signal is not triggered by some local phenomenon (and to help scientists triangulate its source), LIGO has two detectors. One is in Louisiana and another is in Washington State. Any signal appearing at only one detector — meaning it’s local — will be ignored.
Explainer: What is a computer model?
Scientists initially found gravity waves coming from the collision of two black holes. But those are not the only sources they think they will be able to detect. By working with computer simulations, also known as computer models , scientists can figure out what type of signals to expect from other sources.
A neutron star is the core left behind after a massive star explodes. A spinning neutron star should whip up spacetime at frequencies similar to those produced by colliding black holes.
Powerful explosions known as supernovas are triggered when a massive star dies. They can shake up space and blast the cosmos with a burst of high-frequency gravity waves.
Pairs of gargantuan black holes, each more than 1 million times as massive as the sun — and larger than the ones that Advanced LIGO detected — radiate long, undulating waves. Advanced LIGO can’t detect waves at this frequency. But scientists might spot them by looking for subtle variations in the steady beats of pulsars. Pulsars are spinning, ultra-dense neutron stars.
The Big Bang might have triggered universe-sized gravitational waves 13.8 billion years ago. These waves would have left an imprint on the first light released into the cosmos 380,000 years later. Scientists now are looking for these waves today in the cosmic microwave background. That’s the radiation left behind from the Big Bang.
Power Words
(for more about Power Words, click here )
acceleration A change in the speed or direction of some object.
atom The basic unit of a chemical element. Atoms are made up of a dense nucleus that contains positively charged protons and neutrally charged neutrons. The nucleus is orbited by a cloud of negatively charged electrons.
black hole A region of space having a gravitational field so intense that no matter or radiation (including light) can escape.
Big Bang The rapid expansion of dense matter that, according to current theory, marked the origin of the universe. It is supported by physics’ current understanding of the composition and structure of the universe.
compression Pressing on one or more sides of something in order to reduce its volume.
computer model A program that runs on a computer that creates a model, or simulation, of a real-world feature, phenomenon or event.
cosmic An adjective that refers to the cosmos — the universe and everything within it.
cosmic microwave backgroundradiation
The heat left over from the Big Bang and that should exist throughout the universe. It is estimated to be about 2.725 degrees above absolute zero.
cosmos (adj. cosmic ) A term that refers to the universe and everything within it.
frequency The number of times a specified periodic phenomenon occurs within a specified time interval. (In physics) The number of wavelengths that occurs over a particular interval of time.
galaxy (adj. galactic ) A massive group of stars bound together by gravity. Galaxies, which each typically include between 10 million and 100 trillion stars, also include clouds of gas, dust and the remnants of exploded stars.
general relativity A set of mathematical expressions that define gravity and space over time (also known as spacetime). It was first published by Albert Einstein in November 1915. The field of research that focuses on this is described as relativistic .
gravitational waves (also known as gravity waves) Ripples in the fabric of space that are produced when masses undergo sudden acceleration. Some are believed to have been unleashed during the Big Bang, when the universe got its explosive start.
gravity Schools tend to teach that gravity is the force that attracts anything with mass, or bulk, toward any other thing with mass. The more mass that something has, the greater its gravity. But Einstein’s general theory of relativity redefined it, showing that gravity is not an ordinary force, but instead a property of space-time geometry. Gravity essentially can be viewed as a curve in spacetime, because as a body moves through space, it follows a curved path owing to the far greater mass of one or more objects in its vicinity.
laser A device that generates an intense beam of coherent light of a single color. Lasers are used in drilling and cutting, alignment and guidance, in data storage and in surgery.
light-year The distance light travels in one year, about 9.48 trillion kilometers (almost 6 trillion miles). To get some idea of this length, imagine a rope long enough to wrap around the Earth. It would be a little over 40,000 kilometers (24,900 miles) long. Lay it out straight. Now lay another 236 million more that are the same length, end-to-end, right after the first. The total distance they now span would equal one light-year.
LIGO (short for Laser Interferometer Gravitational wave Observatory ) A system of two detectors, separated at a great geographical distance, that are used to register the presence of passing gravitational waves.
mass A number that shows how much an object resists speeding up and slowing down — basically a measure of how much matter that object is made from.
neutron star The very dense corpse of what had once been a star with a mass four to eight times that of our sun. As the star died in a supernova explosion, its outer layers shot out into space. Its core then collapsed under its intense gravity, causing protons and electrons in its atoms to fuse into neutrons (hence the star’s name). Astronomers believe neutron stars form when large stars undergo a supernova but aren’t big massive enough to form a black hole. A single teaspoonful of a neutron star, on Earth, would weigh a billion tons.
particle A minute amount of something.
phenomenon Something that is surprising or unusual.
proton A subatomic particle that is one of the basic building blocks of the atoms that make up matter. Protons belong to the family of particles known as hadrons.
pulsar The name for a spinning, ultra-dense neutron star. A single teaspoonful, on Earth, would weigh a billion tons. It represents the end of life for stars that had started out four to eight times the mass of our sun. As the star died in a supernova explosion, its outer layers shot out into space. Its core then collapsed under its intense gravity, causing protons and electrons in the atoms that had made it up to fuse into neutrons (hence the star’s name). When these stars rotate, they emits short, regular pulses of radio waves or X-rays (and occasionally both at alternate intervals).
radiation (in physics) One of the three major ways that energy is transferred. (The other two are conduction and convection.) In radiation, electromagnetic waves carry energy from one place to another. Unlike conduction and convection, which need material to help transfer the energy, radiation can transfer energy across empty space.
simulate To deceive in some way by imitating the form or function of something. A simulated dietary fat, for instance, may deceive the mouth that it has tasted a real fat because it has the same feel on the tongue — without having any calories. A simulated sense of touch may fool the brain into thinking a finger has touched something even though a hand may no longer exists and has been replaced by a synthetic limb. (in computing) To try and imitate the conditions, functions or appearance of something. Computer programs that do this are referred to as simulations .
spacetime A term made essential by Einstein’s theory of relativity, it describes a designation for some spot given in terms of its three-dimensional coordinates in space, along with a fourth coordinate corresponding to time.
star The basic building block from which galaxies are made. Stars develop when gravity compacts clouds of gas. When they become dense enough to sustain nuclear-fusion reactions, stars will emit light and sometimes other forms of electromagnetic radiation. The sun is our closest star.
subtle Some feature that may be important, but can be hard to see or describe. For instance, the first cellular changes that signal the start of a cancer may be visible but subtle — small and hard to distinguish from nearby healthy tissues.
supernova (plural: supernovae or
supernovas) A massive star that suddenly increases greatly in brightness because of a catastrophic explosion that ejects most of its mass.
theory (in science) A description of some aspect of the natural world based on extensive observations, tests and reason. A theory can also be a way of organizing a broad body of knowledge that applies in a broad range of circumstances to explain what will happen. Unlike the common definition of theory, a theory in science is not just a hunch. Ideas or conclusions that are based on a theory — and not yet on firm data or observations — are referred to as theoretical . Scientists who use mathematics and/or existing data to project what might happen in new situations are known as theorists.
triangulate To figure out where something is by analyzing the timing of signals arriving at different receivers.
undulate To rise and fall in a predictable, wavelike way. This pattern can refer to motion, sound or shapes. Ocean waves are one example of undulations. So is the wavelike motion of a snake.
universe The entire cosmos: All things that exist throughout space and time. It has been expanding since its formation during an event known as the Big Bang, some 13.8 billion years ago (give or take a few hundred million years).
wave A disturbance or variation that travels through space and matter in a regular, oscillating fashion.
Further Reading
A. Grant. “Gravity waves detected at last.” Science News for Students.
February 11, 2015.
M. Bartusiak. “ How to catch a gravity wave .” Science News for Students . February 11, 2016.
A. Grant. “New recipe for monster black holes .” Science News for Students . January 11, 2016.
A. Grant. “Zombie stars: A source of gravitational waves? ” Science News for Students. December 28, 2015.
T. Siegfried. “Einstein taught us: It’s all relative.” Science News for Students. November 4, 2015.
A. Grant. “Dust erases evidence of primordial gravity waves .” Science News for Students. February 10, 2015.
J. Raloff. “ Picture This: Smiley face in space!” Science News for Students. February 9, 2015.
C. Crockett. “Black holes are on collision course.” Science News for Students. January 18, 2015.
S. Ornes. “ Waves from the birth of time.” Science News for Students. March 22, 2014.
Orginal Journal Source : B. P. Abbott et al . Observation of gravitational waves from a binary black hole merger . Physical Review Letters . Published online February 11, 2016. doi: 10.1103/PhysRevLett.116.061102.