Hearing Fear & Mitochondrial DNA | SciByte 100

We take a look at fear and hearing, legislation about embryos with three parents, a flashlight without batteries, spacecraft updates, viewer feedback, Curiosity news, and as always take a peek back into history and up in the sky this week.

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Show Notes:

Sound and Fear

• Researchers are looking into how our emotions can actually affect how we hear and process sound
• The study showed that when certain types of sounds become associated in our brains with strong emotions, hearing similar sounds can evoke those same feelings
• This phenomenon commonly seen in combat veterans suffering from post-traumatic stress disorder (PTSD)
• The Study
• Now a pair of researchers has discovered how fear can actually increase or decrease the ability to discriminate among sounds depending on context
• The study used emotional conditioning in mice to investigate how hearing acuity (the ability to distinguish between tones of different frequencies) can change following a traumatic event, known as emotional learning
• In these experiments animals learn to distinguish between potentially dangerous and safe sounds-called \”emotional discrimination learning.\”
• This type of conditioning tends to result in relatively poor learning, but they designed a series of learning tasks intended to create progressively greater emotional discrimination in the mice, varying the difficulty
• What They Found
• The researchers found that, as expected, fine emotional learning tasks produced greater learning specificity than tests in which the tones were farther apart in frequency
• Animals presented with sounds that were very far apart generalize the fear that they developed to the danger tone over a whole range of frequencies
• Animals presented with the two sounds that were very similar exhibited specialization of their emotional response
• Pitch discrimination abilities were measured in the animals, the mice with more specific responses displayed much finer auditory acuity than the mice who were frightened by a broader range of frequencies
• Sound, Fear, and the Brain
• Another interesting finding of this study is that the effects of emotional learning on hearing perception were mediated by a specific brain region, the auditory cortex
• The auditory cortex has been known as an important area responsible for auditory plasticity
• Surprisingly researchers found that the auditory cortex did not play a role in emotional learning
• The specificity of emotional learning is controlled by the amygdala and sub-cortical auditory areas
• Research shows that amygdala performs a primary role in the processing of memory and emotional reactions
• The researchers hypothesize is that the amygdala and cortex are modifying subcortical auditory processing areas.
• The sensory cortex is responsible for the changes in frequency discrimination, but it\’s not necessary for developing specialized or generalized emotional responses
• Further Reading / In the News
• Researchers discover link between fear, sound perception | MedicalXPress

— NEWS BYTE —

DNA Splicing

• The Low Down
• Structures within eukaryotic cells that convert the chemical energy from food into a form that cells can use
• In humans, mitochondrial DNA can be regarded as the smallest chromosome coding for only 37 genes and containing only about 16,600 base pairs
• Human mitochondrial DNA was the first significant part of the human genome to be sequenced.
• What’s New?
• The U.K. government is moving toward allowing a new type of in vitro fertilization that would enable patients with mitochondrial diseases to avoid passing the condition to their children
• The technique is controversial, because it involves introducing new DNA into a human embryo
• The Department of Health announced that it would draw up draft guidelines to allow fertility clinics to offer the technique
• The proposed guidelines would be released for public comment later this year, and Parliament could vote on a final version next year
• Mitochondria are the cell\’s power generators, and they carry their own DNA, called mtDNA
• Mutations in those genes cause mitochondrial diseases, which can affect various organs, including the heart, liver, eyes, and brain
• Such diseases are passed from mother to child, because the egg provides most of an embryo\’s mtDNA
• The techniques transfer the nuclear DNA from the sperm and egg of the potential parents into a second egg, provided by a donor who has healthy mitochondria, from which the nuclear DNA has been removed
• The technique is still under development and isn\’t yet considered ready to try in humans
• Multimedia
• YouTube | Mitochondrial DNA | genetree
• YouTube | The Four Types of DNA | genetree
• Further Reading / In the News
• U.K. Government Plans to Allow Mitochondrial Replacement – ScienceInsider | news.ScienceMag.org
• Regulator to consult public over plans for new fertility treatments | The guardian | 2012-09-17
• Pronuclear transfer in human embryos to prevent transmission of mitochondrial DNA disease | Nature.com | 2010-05
• Scientists reveal gene-swapping technique to thwart inherited diseases | Guardian.co.uk | 2010-04-14
• Genetically altered babies born | BBC News | 2008-04-26

Student Develops No-Battery Flashlight

• Ann Makosinski from Victoria, British Columbia, has an LED flashlight powered by body heat her flashlight has got her into the finalist ranks for the Google Science Fair
• The Hollow Flashlight, which works according to the thermoelectric effect-creating electric voltage out of temperature difference
• How it Works : The Basics
• Thermoelectric effect is the direct conversion of temperature differences to electric voltage and vice-versa
• At the atomic scale, an applied temperature gradient causes charge carriers in the material to diffuse from the hot side to the cold side
• The flashlight Uses four Peltier tiles and the temperature difference between the palm of the hand and ambient air
• It only needs a five degree temperature difference to work and produce up to 5.4 mW at 5 foot candles of brightness
• Design
• She bought Peltier tiles and tested them to see if they could produce sufficient power to light an LED
• While power was not a problem, getting the needed voltage was, as the tiles did not generate enough of the voltage needed
• Research and experiments on different designs for the circuit design lead to a circuit that could provide enough voltage when used with a recommended transformer
• Final Design
• The final design included mounting the Peltiers on a hollow aluminum tube which was inserted in a larger PVC pipe with an opening that allowed ambient air to cool the tube
• The palm wrapped around a cutout in the PVC pipe and warmed the tiles.
• The result was a bright light at 5 degree Celcius [sic] of Peltier differential
• Materials for the flashlight project cost her $26
• Google Science Fair
• The top winner gets a $50,000 scholarship and trip to the Galapagos Islands
• The prize ceremony takes place in September. Winners will be chosen in different age categories-13-14, 15-16, 17-18.
• Multimedia
• YouTube | The Human Heat Powered Flashlight | smustube
• Further Reading / In the News
• Student\’s flashlight works by body heat, not batteries | Phys.org

— TWO-BYTE NEWS —

Space Shuttle Atlantis

• The Space Shuttle Atlantis exhibition opened at NASA\’s Kennedy Space Center Visitor Complex on June 29
• The retired orbiter is displayed at an angle, with its cargo bay doors open and robotic arm outstretched
• Atlantis dominates the center of a multistory building that allows views of the orbiter from many angles.
• Multimedia
• YouTube Space Shuttle Atlantis exhibit set to launch | collectSPACE
• Further Reading / In the News
• Atlantis Exhibit – Kennedy Space Center | kennedyspacecenter.com
• Space Shuttle Atlantis Exhibit \’Incredible,\’ \’Breathtaking\’ | NASA Shuttle Program | Space.com

— SPACECRAFT UPDATE—

Voyager 1\’s Journey, It\’s Not There Yet

• Voyager 1 is 11.6 billion miles (18.6 billion kilometers) from the Sun, poised to become Earth\’s first robotic mission to interstellar space
• Data from the Voyager 1 spacecraft continues to provide new insight on the outskirts of our solar system
• New Publications
• In papers published in the journal Science, scientists have provided more clarity on the region they named the \”magnetic highway\” in December 2012.
• The new Science papers focus on observations from the summer and fall of 2012 by LECP as well as Voyager 1\’s Cosmic Ray and Magnetometer instruments, with additional LECP data through April 2013.
• Voyager has detected, for the first time, low-energy galactic cosmic rays, now that particles of the same energy from inside the bubble around our Sun disappeared
• The most dramatic part was how quickly the solar-originating particles disappeared; they decreased in intensity by more than 1,000 times
• Voyager\’s Low-Energy Charged Particle (LECP)
• Voyager\’s Low-Energy Charged Particle (LECP) instrument, LECP detector, was designed at APL in the 1970s.
• It includes a stepper motor that rotates the instrument through 45-degree steps every 192 seconds
• It allows it to gather data in all directions and pick up something as dynamic as the solar wind and galactic particles
• The device, designed and tested to work for 500,000 steps and last four years, has been working for nearly 36 years and well past 6 million steps
• That\’s 12 times the number of steps and 9 times the number of years as of early July 2013
• Important to remember
• Voyager 1 may be months or years from leaving the solar system
• Further Reading / In the News
• At the solar system\’s edge, more surprises from Voyager | Phys.org
• Voyager 1 Reaches Gateway to the Galaxy – News Watch | newswatch.NationalGeographic.com
• News in Brief: Voyager 1 on fast track toward interstellar space | Science News
• Voyager 1 Entered Weird Region In Space Last Summer | Popular Science

— VIEWER FEEDBACK —

Did You See This? | Radio Signals from Outside the Milky Way

• Sent in From Nick Tanin
• Four powerful radio pulses emanating from sources outside of the Milky Way, 5 billion to nearly 11 billion light years away, have been picked up by an international team of astronomers at the Parkes Radio Telescope in Australia
• What Was Seen
• These bursts gave off more energy in a millisecond than the sun does in 300,000 years
• The bursts ranged from 5.5 to 10 billion light-years away, meaning it took the light from some of them 10 billion years to reach Earth. [The Big Bang occurred 13.8 billion years ago]
• To determine whether the new signals came from inside or outside the Milky Way scientists studied how the radio waves were affected by the material they pass through
• This technique allows these new objects to shed light on the components of space.
• As radio waves travel in space, they are stretched and slowed by the ionized material through which they move
• Using models, the team concluded that the fast radio bursts, FRBs, traveled billions of light-years – much farther than the edge of Earth\’s galaxy, and likely are located in another galaxy
• Although the explosions were brief, the astronomers can pinpoint the bursts\’ locations pretty accurately
• They are so bright and narrow that we can limit the size of the emission region at the source to just a few hundred kilometers
• No corresponding object could be observed in optical, gamma or X-ray wavelengths, so the explosions\’ origins remain unknown to scientists
• Additional observations were performed approximately a year after the FRBs were first spotted, looked at whether the objects continued to produce emission, but the signals appear to be non repeating
• Efforts are ongoing at the moment to detect FRBs in close to real time, such that they can be followed up quickly
• Have we Observed This Kind of Event Before?
• Since there had been only one burst during the last observation seven years ago scientists had wondered if the reading was simply an artifact in the data
• Now the four new blips may add weight to that observation
• Possible Sources
• Intersecting magnetic fields from two neutron stars, extremely dense city-size bodies packing the mass of the sun.
• A special kind of supernova orbited by a neutron star could potentially produce radio bursts as the star\’s magnetic field interacts with the explosion of the supernova
• Such combinations would be rare
• The current leading explanation is that a giant burst from a magnetar, a highly magnetized type of neutron star
• Are There Other Events Like This?
• These newfound objects allowed the researchers to calculate that an FRB should occur once every 10 seconds
• Telescopes capture radio waves from such a small fraction of the sky so one-time radio pulses have been hard to detect
• Instruments lack the ultrafast time resolution required to pinpoint the short-lived bursts
• Further Reading / In the News
• News in Brief: Distant radio-wave pulses spotted | Atom & Cosmos | Science News
• Mysterious Extragalactic Explosions Baffle Astronomers | Fast Radio Bursts | Space.com

— CURIOSITY UPDATE —

• Moon, Phobos, Gets its Time to Shine
• Phobos, the larger of the two moons of Mars, passing overhead, as observed by NASA\’s Mars rover Curiosity
• The \”video\” is a series of images centered straight overhead starting shortly after sunset
• Phobos first appears near the lower center of the view and moves toward the top of the view
• The clip runs at accelerated speed; the amount of time covered in it is about 27 minutes
• The 86 frames combined into this clip were taken by the rover\’s Navigation Camera (Navcam) on the 317th Martian day of Curiosity\’s work on Mars (June 28, 2013, PDT)
• Multimedia
• YouTube | Mars Moon Phobos Seen By Curiosity | VideoFromSpace
• Image | Phobos Passing Overhead | mars.jpl.nasa.gov
• Image | Curiosity\’s Traverse Map Through Sol 317 | mars.jpl.nasa.gov
• Image Galleries at JPL and Curiosity Mulimedia
• Social Media
• Curiosity Rover @MarsCuriosity
• Further Reading / In the News
• Phobos Passing Overhead | mars.jpl.nasa.gov

SCIENCE CALENDAR

Looking back

• July 14, 1965 : 48 years ago : First Mars close-up photo : The Mariner 4 satellite sent a transmission of the first close-up photograph of Mars. It consisting of 8.3 dots per second of varying degrees of darkness. The transmission lasted for 8.5 hours and depicted the regions on Mars known as Cebrenia, Arcadia, and Amazonis. The satellite was 134 million miles away from earth and 10,500 miles from Mars. The 574-pound spacecraft had been launched at 9:22am on 28 Nov 1964, from Cape Canaveral, FL, by a two-stage Atlas-Agena D rocket. In addition to its camera with digital tape recorder (about 20 pictures), it carried instruments for studying cosmic dust, solar plasma, trapped radiation, cosmic rays, magnetic fields, radio occultation and celestial mechanics

Looking up this week

• Keep an eye out for …
• Wed, July 10 | Just after sunset | In the West, watch for a thin crescent Moon just above the horizon, to the lower left of Venus
• Thurs, July 11 | As twilight fades | The crescent Moon is still low on the western horizon, but now Venus is roughly ~1.5 fist widths (~22-23*) held at arms lengths to the right
• Fri, July 12 | Twilight | To the West just slightly above the midpoint of the Moon and Venus you might be able to see Regulus, the brightest star in the constellation Leo and actually two binary stars
• Planets
• Venus | Gradually rising in altitude to the W-NW in the evening twilight
• Mars / Jupiter | Deep in the glow of dawn

• Saturn | In the SW after dusk with Spica a little over a fist held at arms length (12*) to the lower right

• Further Reading and Resources

• Sky&Telescope
• SpaceWeather.com
• StarDate.org
• For the Southern hemisphere: SpaceInfo.com.au
• Constellations of the Southern Hemisphere : astronomyonline.org
• Royal Astronomical Society of New Zealand : rasnz.org.nz
• AstronomyNow
• HeavensAbove