Bee-ophysics in the news – Ostroverkhova lab studies bee visual response

Posted on by

The Ostroverkhova group’s work on bee vision had attracted a lot of attention!

Ostroverkhova et al examined responses of wild bees to traps designed to selectively stimulate either the blue or the green photoreceptor using sunlight-induced fluorescence in the 420-480 nm or 510-540 nm region. Image credit: Rebekka D.

KATU has an interview with Oksana Ostroverkhova at: https://katu.com/news/local/wild-bees-are-attracted-to-blue-fluorescent-light-oregon-state-university-research-finds

Sci-news has an article http://www.sci-news.com/biology/bees-blue-fluorescent-light-06121.html

and there is a press release to go with their recent paper in Journal of Comparative Physiology A. https://link.springer.com/article/10.1007/s00359-018-1269-x

CORVALLIS, Ore. – Researchers at Oregon State University have learned that a specific wavelength range of blue fluorescent light set bees abuzz.

The research is important because bees have a nearly $15 billion dollar impact on the U.S. economy – almost 100 commercial crops would vanish without bees to transfer the pollen grains needed for reproduction.

“The blue fluorescence just triggered a crazy response in the bees, told them they must go to it,” said the study’s corresponding author, Oksana Ostroverkhova. “It’s not just their vision, it’s something behavioral that drives them.”

The findings are a powerful tool for assessing and manipulating bee populations – such as, for example, if a farmer needed to attract large numbers of bees for a couple of weeks to get his or her crop pollinated.

“Blue is broad enough wavelength-wise that we needed to figure out if it mattered to the bees if the light emitted by the sunlight-illuminated trap was more toward the purple end or the green end, and yes, it mattered,” Ostroverkhova said. “What’s also important is now we’ve created traps ourselves using stage lighting filters and fluorescent paint – we’re not just reliant on whatever traps come in a box. We’ve learned how to use commercially available materials to create something that’s very deployable.”

Fluorescent light is what’s seen when a fluorescent substance absorbs ultraviolet rays or some other type of lower-wavelength radiation and then immediately emits it as higher-wavelength visible light – think about a poster whose ink glows when hit by the UV rays of a blacklight.

Like humans, bees have “trichromatic” vision: They have three types of photoreceptors in their eyes.

Both people and bees have blue and green receptors, but the third type for people is red while the third kind for bees is ultraviolet – electromagnetic energy of a lower wavelength that’s just outside the range of human vision.

Flowers’ vibrant colors and patterns – some of them detectable only with UV sight – are a way of helping pollinators like bees find nectar, a sugar-rich fluid produced by plants. Bees get energy from nectar and protein from pollen, and in the process of seeking food they transfer pollen from a flower’s male anther to its female stigma.

Building on her earlier research, Ostroverkhova, a physicist in OSU’s College of Science, set out to determine if green fluorescence, like blue, was attractive to bees. She also wanted to learn whether all wavelengths of blue fluorescence were equally attractive, or if the drawing power tended toward the green or violet edge of the blue range.

In field conditions that provided the opportunity to use wild bees of a variety of species – most bee-vision studies have been done in labs and used captive-reared honeybees – Ostroverkhova designed a collection of bee traps – some non-fluorescent, others fluorescent via sunlight – that her entomology collaborators set up in the field.

Under varying conditions with a diverse set of landscape background colors, blue fluorescent traps proved the most popular by a landslide.

Researchers examined responses to traps designed to selectively stimulate either the blue or the green photoreceptor using sunlight-induced fluorescence with wavelengths of 420 to 480 nanometers and 510 to 540 nanometers, respectively.

They found out that selective excitation of the green photoreceptor type was not attractive, in contrast to that of the blue.

“And when we selectively highlighted the blue photoreceptor type, we learned the bees preferred blue fluorescence in the 430- to 480-nanometer range over that in the 400-420 region,” Ostroverkhova said.

Findings were recently published in the Journal of Comparative Physiology A. The Agricultural Research Foundation and OSU supported this research.

\

Editor’s note: Images are available at http://bit.ly/2JO7ypl and http://bit.ly/2MA4080

In Memorium: Jim Ketter (1957-2018)

Posted on by
Jim Ketter at a Dept. Picnic, photo by Randall Milstein

Jim Ketter, who served as lab guru and instructor for many years, passed away on June 6th 2018. Jim joined our department in 2005 after a varied career as a geophysicist, high school teacher, graduate student and physics instructor at LBCC and Oregon State.  He was a warm and sensitive instructor and the go-to gadget guy who kept our labs running and our department presentable. In addition to the considerable load of teaching and keeping our labs humming, he loved doing outreach – Discovery days, supervising the SPS and generally bringing his enthusiasm for physics to everyone he met.

There will be a  celebration of life for Jim on July 14th from 2pm-5pm at Deluxe Brewing: 635 NE Water Ave. Albany, Oregon.

http://www.fisherfuneralhome.com/obituary/Jim-Ketter/Albany-Oregon/1802004

has more details and an obituary.

His family requests that donations in his memory go to Albany Parks and Recreation Foundation in lieu of flowers.

OSU press release: Fungi-produced pigment shows promise as semiconductor material

Posted on by

The Ostraverkhova group’s work on xylindein, an organic semiconductor produced naturally by fungi, has been featured in a press release.

http://today.oregonstate.edu/news/fungi-produced-pigment-shows-promise-semiconductor-material

June 5, 2018
CORVALLIS, Ore. – Researchers at Oregon State University are looking at a highly durable organic pigment, used by humans in artwork for hundreds of years, as a promising possibility as a semiconductor material.
Findings suggest it could become a sustainable, low-cost, easily fabricated alternative to silicon in electronic or optoelectronic applications where the high-performance capabilities of silicon aren’t required.
Optoelectronics is technology working with the combined use of light and electronics, such as solar cells, and the pigment being studied is xylindein.
“Xylindein is pretty, but can it also be useful? How much can we squeeze out of it?” said Oregon State University physicist Oksana Ostroverkhova. “It functions as an electronic material but not a great one, but there’s optimism we can make it better.”
Xylindien is secreted by two wood-eating fungi in the Chlorociboria genus. Any wood that’s infected by the fungi is stained a blue-green color, and artisans have prized xylindein-affected wood for centuries.
The pigment is so stable that decorative products made half a millennium ago still exhibit its distinctive hue. It holds up against prolonged exposure to heat, ultraviolet light and electrical stress.
“If we can learn the secret for why those fungi-produced pigments are so stable, we could solve a problem that exists with organic electronics,” Ostroverkhova said. “Also, many organic electronic materials are too expensive to produce, so we’re looking to do something inexpensively in an ecologically friendly way that’s good for the economy.”
With current fabrication techniques, xylindein tends to form non-uniform films with a porous, irregular, “rocky” structure.
“There’s a lot of performance variation,” she said. “You can tinker with it in the lab, but you can’t really make a technologically relevant device out of it on a large scale. But we found a way to make it more easily processed and to get a decent film quality.”
Ostroverkhova and collaborators in OSU’s colleges of Science and Forestry blended xylindein with a transparent, non-conductive polymer, poly(methyl methacrylate), abbreviated to PMMA and sometimes known as acrylic glass. They drop-cast solutions both of pristine xylindein and a xlyindein-PMMA blend onto electrodes on a glass substrate for testing.
They found the non-conducting polymer greatly improved the film structure without a detrimental effect on xylindein’s electrical properties. And the blended films actually showed better photosensitivity.
“Exactly why that happened, and its potential value in solar cells, is something we’ll be investigating in future research,” Ostroverkhova said. “We’ll also look into replacing the polymer with a natural product – something sustainable made from cellulose. We could grow the pigment from the cellulose and be able to make a device that’s all ready to go.
“Xylindein will never beat silicon, but for many applications, it doesn’t need to beat silicon,” she said. “It could work well for depositing onto large, flexible substrates, like for making wearable electronics.”
This research, whose findings were recently published in MRS Advances, represents the first use of a fungus-produced material in a thin-film electrical device.
“And there are a lot more of the materials,” Ostroverkhova said. “This is just first one we’ve explored. It could be the beginning of a whole new class of organic electronic materials.”
The National Science Foundation supported this research.
About the OSU College of Science:  As one of the largest academic units at OSU, the College of Science has seven departments and 12 pre-professional programs. It provides the basic science courses essential to the education of every OSU student, builds future leaders in science, and its faculty are international leaders in scientific research.

 

PhIS events

Posted on by

The PhIS group (Physicists for inclusion in Science) has been busy this year! The group fosters inclusion by providing an inclusive community, professional development opportunities, and mentorship for aspiring physicists. This year, their activities have included coffee breaks, mixers (including an amazing dinner and silent auction for the department), book clubs, and many outreach activities.  Check out all the fun at http://blogs.oregonstate.edu/phis/2018/05/07/physicists-inclusion-science-phis/ .  The 2018/19 elections have happened and the new PhIS leadership is: MacKenzie Lenz (President), Kelby Hahn (Vice President), Mike Vignal (Treasurer), Mattia Carbonara (Secretary).  They invite everyone to join!

Paper Summaries: Simultaneous fluorescence and surface charge measurements on organic semiconductor-coated silica microspheres

Posted on by

Rebecca Grollman, Graham Founds, Rick Wallace and  Oksana Ostroverkhova’s paper “Simultaneous fluorescence and surface charge measurements on organic semiconductor-coated silica microspheres” has been featured by Advances in Engineering  as a key scientific article contributing to excellence in science and engineering research.  See

https://advanceseng.com/simultaneous-fluorescence-surface-charge-measurements/

for a short summary of the paper and a short video highlighting the result.

Paper Summaries – To beam or not to beam: OSU research shows sign of a misaligned jet in the gravitational wave source GW170817

Posted on by
Model predictions for flux vs time(solid lines) compared to observations (symbols).
GW170817, detected on August 17, 2017, was the first multi-messenger astronomical source, seen in gravitational waves and across the whole electromagnetic spectrum. Much of the physics of this source has been understood thanks to the high quality data collected for months after the initial detection. We now know that it was due to the collision between two neutron stars, a class of very massive and compact stars that were in orbit around each other and eventually merged forming a black hole. During the collision material was flung out in all directions. Most of the material was sent in the equatorial direction, where new atoms – such as gold and platinum – were formed through rapid neutron capture. Some material was sent in the polar direction, but exactly how much and with what energy is not known, since our observing geometry is far from the polar axis. For that reason, it had been impossible to ascertain whether a short gamma-ray burst also took place with the star collision.
Short gamma-ray bursts are some of the brightest explosions recorded in present day universe. They are produced when extremely fast outflows are sent in our direction by leftover material that accretes onto a newly formed black hole. Scientists believe they should be caused by a neutron star collision, but direct evidence is not yet available. When we detect  the burst directly, it is so bright that outshines all the signs of the neutron star collision. Groundbreaking research performed by the astrophysics group led by Dr. Lazzati and accepted for publication in Physical Review Letters, however, has shown that the unusual increase of the luminosity of GW170817 over time is a sign that a short GRB did happen right after the merger, albeit along a different direction. The figure displays the model predictions (solid lines) along with the observations (symbols), showing the excellent agreement of the model with the data.

Oregon State Physics wins national award for Improving Undergraduate Physics Education

Posted on by

The American Physical Society has recognized OSU Physics for Improving Undergraduate Physics Education.

We are one of three institutions to receive the award this year. https://www.aps.org/programs/education/undergrad/faculty/awardees.cfm  explains the award and lists previous winners

“ For 21 years, the physics department at Oregon State has been a national model for its holistic approach to improving the educational experience for undergraduates, from the nationally recognized, upper division curriculum redesign—Paradigms in Physics, through lower‐division reform, thesis research experiences for all majors, and attention to co‐curricular community‐building. We are dedicated to building a strong cohort group of students, prepared for a wide range of careers. For the broader community, we produce and freely share cutting‐edge curricular materials based on our own physics education research.”

Yunker Lecture this week – Laura Greene at 5PM on Friday the 20th

Posted on by

Just a reminder that our annual Yunker Lecture is this Friday the 20th.

Laura Greene (center) in her natural habitat

 

330 PM in Weniger 328 is a reception/poster show

500 PM in Weniger 151 is the lecture by Prof. Laura Green, Chief Scientist at the National Magnetic Field Laboratory and past president of the American Physical Society.

http://impact.oregonstate.edu/2018/04/yunker-lecture-explores-dark-energy-quantum-materials/  has a longer description.  One correction is that the reception is now in Weniger 328 instead of 379.