Policing the digital divide: How racial bias can limit Internet access for people of color

New research shows that the policing of nonviolent offenses, like loitering, restricts access to free Wi-Fi, particularly for people of color

UNIVERSITY OF PENNSYLVANIA

Research News

Coffee shops and casual restaurants are an important part of American life. Even beyond the food and drinks they sell, they offer us a place to use the restroom or rest our feet while we're out and about, and they provide internet access to those on the go, those in need of a temporary office, or those who don't have an internet connection at home. Many of us take for granted that a nearby Starbucks or McDonald's can offer us a little respite, even if we don't always make a purchase.

But access to these sorts of quasi-public spaces isn't always equal in America, particularly for Black people and other people of color. One such example of this is the infamous 2018 incident in Philadelphia when two Black men waiting at Starbucks for an acquaintance were arrested for loitering. The national outcry over their biased and unjust treatment led to a change in Starbucks' corporate policy. It also begs the question: how often does this kind of incident happen around the country and what implications does it have?

A new study published in the Journal of Communication from researchers at the Annenberg School for Communication at the University of Pennsylvania investigated the ways that institutions control who has access to Wi-Fi. The findings indicate that powerful institutions and privileged people use quality-of-life policing -- the report and/or arrest of individuals engaged in nonviolent offenses such as loitering, noise violations, and public intoxication -- to keep those with less privilege, including people of color, from accessing resources like the internet.

The inspiration for the study came from a story Professor Julia Ticona heard while interviewing gig workers for her forthcoming book, Left to Our Own Devices: Coping with Insecure Work in a Digital Age (Oxford University Press). One of her interviewees, a 20-year-old Black man named Alex, had a Starbucks manager threaten to call the police on him because he was using an outlet and the internet.

"I was so frustrated for him personally," says Ticona. "And I was also frustrated that we so often talk about the digital divide as a matter of people not being able to afford access, entirely omitting from the discussion that people are actively being threatened for using the internet."

Ticona shared her frustration with Professor Yphtach Lelkes and doctoral candidate Tian Yang, and the three scholars joined forces to develop a method for investigating whether and how institutions are policing access to the internet.

"This paper is a great example of disciplinary cross-fertilization" says Lelkes. "Julia and I have offices across the hall from one another, and Tian was working with me as a research fellow and taking Julia's class at the time. This project came about because Annenberg is such a big tent when it comes to methods and ways of thinking, and the school encourages collaborations between its various scholars."

The researchers analyzed publicly available data to determine whether quality-of-life policing increased, decreased, or remained the same once free Wi-Fi was introduced to restaurants -- namely Burger King, McDonald's, Panera, Starbucks, and Wendy's -- in various neighborhoods in Chicago between 2008 and 2016. They compiled their own dataset for the study, combining crime data from the police department, neighborhood information from the U.S. Census Bureau, and the locations of stores listed on business licenses.

"We were excited to be able to establish a causal relationship between institutional dynamics and their outcomes in perpetuating social inequalities," says Yang. "To do this, we applied methods used in economics and other fields to develop a way to analyze the data for answers to our questions."

The researchers found that wealthier, whiter neighborhoods had a 5% increase in quality-of-life complaints to the police after restaurants began offering internet access, while other neighborhoods did not. They also found that those same wealthy, white neighborhoods did not have an increase in the report of other kinds of crime, like assault or burglary. The researchers believe their findings suggest that economic hurdles aren't the only factor shaping people's internet access, but that active exclusion from public spaces -- where some people are allowed to enjoy Wi-Fi and others aren't -- also contributes to the digital divide.

"This paper connects ongoing conversations about the role of institutions in perpetuating white supremacy and privilege in the digital age to long-standing questions about digital access," says Ticona. "We hope this study can contribute to the efforts to have a different kind of conversation in the field of Communication about the role of policing, race, and class in reinforcing digital inequalities."

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The study, entitled "Policing the Digital Divide: Institutional Gate-Keeping and Criminalizing Digital Inclusion," was published in the Journal of Communication. Authors include Tian Yang, Julia Ticona, and Yphtach Lelkes.

Thoreau's Lumberjack

An overzealous commitment of humanism leads to a sharp man/nature duality, or to a polarity of the higher human spirit versus the lower natural body. 

In some parts of Thoreau's Walden, such a duality is evident. In a language that echoes the sharp dualism of the Christian faith, Thoreau speaks of the transcendental mind "descending" into the natural body to "redeem" it (349). He even finds an inverse ratio between the body and the soul. "The animal in us," says he, "awakens in proportion as our higher nature slumbers." He quotes Mencius to the effect that the difference between man and the brute is very slim. In the raging battle within man, where the human side is pitted against the animal side, ordinary people very soon lose the distinctly human, while "superior men preserve it carefully" (346).

PURE CLASSISM
The duality at times turns into a sharp polarity where nature inspires Thoreau's deepest fears, if not his contempt. The Canadian woodchopper, "a simple natural man," (227) was so absorbed in nature that Thoreau painted him as being unable to absorb "the spiritual view of things." To Thoreau, "the highest that he appeared to conceive of was a simple expediency, such as you might except an animal to appreciate" (279).

It is this disdain for nature that led Thoreau in "Higher Laws" to speak with some remorse about the inability to expel "the reptile and sensual" aspects of human nature, drawing analogies from physical nature to communicate his disgust. "It is like the worms, says he, "which, even in life and health, occupy our bodies (346). Hostility and disdain create the desire for radical transcendence which becomes quite pronounced when Thoreau asserts that "nature is hard to overcome but she must be overcome" (348).

Karl Marx and Swami Vivekananda: It is unknown in India, but Karl Marx and Swami Vivekananda had similar views on the historical cycle of the world. According to Marx the world history has four cycles starting with primitive communism of tribal societies, then feudalism, capitalism and ultimately socialism followed by advanced communism. For Marx the history is deterministic, these cycles are bound to happen due to the contradictions or dialectics in the existing system. In Karl Marx, ”Changes occur in society because of contradictions in prevailing ideology, in its social, economic and political order. These contradictions arise from hostilities between the social classes” (in A Contribution to the Critique of Political Economy, Progress Publishers, Moscow). 

 Swami Vivekananda similarly divided the world history into four cycles, starting with the Age of the Priests, Age of the Warriors, Age of the Merchants as we are now in and ultimately the Age of the Worker, which is coming. With each cycle, society rises to higher and still higher stages and is perfected. The contradiction in the society according to Vivekananda is as follows, “.. At a certain time every society attains its manhood, when a strong conflict ensues between the ruling power and the common people” (Vivekananda, Collected Works, vol.iv, p.399). 

In the new Age of the Workers, “just distribution of material values will be achieved, equality of the rights of all members of society to ownership of property established and caste differences obliterated” (in Vivekananda, Collected Works, vol.vi, p.343). Sri Aurobindo also has expressed similar views on history.

Blushing plants reveal when fungi are growing in their roots

UNIVERSITY OF CAMBRIDGE

Research News

IMAGE: BETALAIN COLOURED ROOTS view more 

CREDIT: TEMUR YUNUSOV AND ALFONSO TIMONEDA

Almost all crop plants form associations with a particular type of fungi - called arbuscular mycorrhiza fungi - in the soil, which greatly expand their root surface area. This mutually beneficial interaction boosts the plant's ability to take up nutrients that are vital for growth.

The more nutrients plants obtain naturally, the less artificial fertilisers are needed. Understanding this natural process, as the first step towards potentially enhancing it, is an ongoing research challenge. Progress is likely to pay huge dividends for agricultural productivity.

In a study published in the journal PLOS Biology, researchers used the bright red pigments of beetroot - called betalains - to visually track soil fungi as they colonised plant roots in a living plant.

"We can now follow how the relationship between the fungi and plant root develops, in real-time, from the moment they come into contact. We previously had no idea about what happened because there was no way to visualise it in a living plant without the use of elaborate microscopy," said Dr Sebastian Schornack, a researcher at the University of Cambridge's Sainsbury Laboratory and joint senior author of the paper.

To achieve their results, the researchers engineered two model plant species - a legume and a tobacco plant - so that they would produce the highly visible betalain pigments when arbuscular mycorrhiza fungi were present in their roots. This involved combining the control regions of two genes activated by mycorrhizal fungi with genes that synthesise red-coloured betalain pigments.

The plants were then grown in a transparent structure so that the root system was visible, and images of the roots could be taken with a flatbed scanner without disturbing the plants.

Using their technique, the researchers could select red pigmented parts of the root system to observe the fungus more closely as it entered individual plant cells and formed elaborate tree-like structures - called arbuscules - which grow inside the plant's roots. Arbuscules take up nutrients from the soil that would otherwise be beyond the reach of the plant.

Other methods exist to visualise this process, but these involve digging up and killing the plant and the use of chemicals or expensive microscopy. This work makes it possible for the first time to watch by eye and with simple imaging how symbiotic fungi start colonising living plant roots, and inhabit parts of the plant root system over time.

"This is an exciting new tool to visualise this, and other, important plant processes. Beetroot pigments are a distinctive colour, so they're very easy to see. They also have the advantage of being natural plant pigments, so they are well tolerated by plants," said Dr Sam Brockington, a researcher in the University of Cambridge's Department of Plant Sciences, and joint senior author of the paper.

Mycorrhiza fungi are attracting growing interest in agriculture. This new technique provides the ability to 'track and trace' the presence of symbiotic fungi in soils from different sources and locations. The researchers say this will enable the selection of fungi that colonise plants fastest and provide the biggest benefits in agricultural scenarios.

Understanding and exploiting the dynamics of plant root system colonisation by fungi has potential to enhance future crop production in an environmentally sustainable way. If plants can take up more nutrients naturally, this will reduce the need for artificial fertilisers - saving money and reducing associated water pollution.

CAPTION

Betalain coloured roots

CREDIT

Temur Yunusov and Alfonso Timoneda

CAPTION

Betalain coloured roots

CREDIT

Temur Yunusov and Alfonso Timoneda

New tracking system monitors danger to rainforests

Scientists develop novel new indicator for monitoring danger to the world's rainforests, which are losing capacity to cycle carbon and water

UNIVERSITY OF DELAWARE

Research News

Rainforests are a powerful, natural solution to combat climate change -- providing water filtration, capturing carbon and regulating global temperatures. But major threats like large-scale land use changes, including agricultural expansion and clearcutting, have turned these biodiversity havens into one of the most endangered habitats on our planet.

In 2019, select scientists, including the University of Delaware's Rodrigo Vargas, met at the National Geographic headquarters in Washington, D.C., to discuss the threats to rainforests. The researchers pinpointed a need to develop a worldwide tracking system, which would find trends to help fight land degradation and promote conservation.

In the paper published on Friday, July 22 in the scientific journal One Earth, these researchers introduce the unique tropical rainforest index (TFVI), a baseline for rainforests across the entire globe. The scientist's goal is to detect and evaluate the vulnerability of rainforests to increasing threats. National Geographic and the Rolex Perpetual Planet Initiative funded the endeavor.

TFVI provides a snapshot of long-term observations, which began in 1982.

"Through this new index, we now have not only global coverage, but uniformity. We can summarize critical information about the health of rainforests," said Vargas, professor of ecosystem ecology and environmental change. "It gives us a benchmark and provides information about looming, future changes."

Using advanced satellite measurements, the research team systematically analyzed the climate and vegetation of each tropical region on Earth. The study's findings suggest that rainforests are losing their capacity to cycle carbon and water.

"We are losing major hotspots for biodiversity and carbon pools," Vargas said. "These are not small patches of land across the world; these are large sections of the Earth's surface."

The study's findings also indicate different regions of tropics have different responses to climate threats. Some regions, like Africa's Congo basin, are more resilient than other parts of the world. The Amazon Basin shows large-scale vulnerability to drying conditions of atmosphere, frequent droughts and large-scale land-use changes. In Southeast Asia, rainforests are stressed more from land use and species fragmentation than they are from climate, except for areas of peatlands that are, during El Nino years, now more vulnerable to fire.

"There is no single solution, no silver bullet that will work in every tropical rainforest. This highlights the needs for localized solutions," Vargas said. "But a general, global index also illuminates the need to design unified strategies to maximize the natural solutions that rainforests provide."

The unique tropical rainforest index methodically illustrates that the susceptibility of rainforests is actually much greater than previous predictions. Disturbed and fragmented areas have lost resilience to climate warming and droughts. Perhaps even more distressing were study findings suggesting that rainforests are losing their capacity to cycle carbon and water.

Tropical forests provide critical environmental services and benefits to society. These rainforests are changing from their historically, highly-diverse status to heavily transformed areas and managed land -- one that lacks the ability to, for example, sequester carbon from the atmosphere and support biodiversity.

"In addition to our moral responsibility to preserve our planet's biodiversity, because human's actions are influencing the global climate, we must be prepared to manage the consequences of these changes," Vargas said.

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Studies examine different understandings, varieties of diversity

Investigates connection between political ideology, attitudes, and beliefs toward diversity

UNIVERSITY OF ILLINOIS AT CHICAGO

Research News

Attitudes toward diversity vary, and its meaning can often be difficult to find consensus about in an increasingly diverse but politically polarized nation such as the United States.

In a report published by Personality and Social Psychology Bulletin, University of Illinois Chicago researchers detail findings from three studies that explore the connection between political ideology, attitudes, and beliefs toward diversity.

"Our studies explored the possibility that atti­tudes toward 'diversity' are multidimensional rather than unidimensional and that ideological differences in diversity attitudes vary as a function of diversity subtype," said the report's lead author Kathryn Howard, UIC doctoral candidate in psychology.

The first study investigated ideological differences in attitudes towards a wide variety of diversity features. Participants rated how much diversity or homogeneity they would desire in 23 different community features that could be considered relevant to diversity.

The study found more conservative participants preferred viewpoint diversity and more liberal participants preferred demographic diversity.

The second study assessed participants' attitudes towards the general concept of diversity without providing a definition of the term. By investigating whether general attitudes towards diversity actually predict how people feel about specific types of diversity, the findings suggest that demographic features may be central to peoples' prototypes of diversity and that positive attitudes towards the general concept of diversity predicted demographic diversity preferences for both conservatives and liberals.

According to the researchers, "liberals were more likely than conservatives to endorse the general concept of diversity. Further, general diversity did not predict viewpoint diversity, but did significantly predict demographic diversity preferences. Thus, it may be that when people think of diversity in the abstract, people primarily imagine differences in ethnic and cultural groups, and do not necessarily consider diversity in attitudes."

Because the first two studies found that diversity is multidimensional and contains at least two distinct factors -- viewpoint and demographic diversity -- the third study aimed to investigate possible variations in the perceived meaning of "diversity" by asking participants to judge the relevance of a set of features to diversity.

Respondents were asked to imagine "a very diverse community," and to think about "the types of people and places that exist in a very diverse community." They also had to determine how relevant 29 different community features were to their image of a diverse community.

"People do not perceive diversity as a unidimensional or even bi-dimensional construct, but rather likely perceive at least three categories of diversity. Further, people rated demographic features as most relevant to diversity, followed by viewpoint and consumer features. Lastly, conservatives rated viewpoint features as more relevant to diversity than liberals, and liberals rated demographic features as more relevant to diversity than conservatives," the report states.

"Conservatives and liberals do not differ only in their attitudes toward diversity, but they also differ in their understanding of what 'diversity' means. When asked to think about 'diversity,' liberals and conservatives think about different things; different aspects of social life come to mind," Howard said.

The divergent political and social media realms where liberals and conservatives are centered, combined with increased political and affective polarization, likely accounts for the difference of perspective on both sides, according to the researchers, who add that the results provide hope for bridging the liberal-conservative political divide.

"Once you recognize that existence of multiple components of 'diversity,' it opens the door to identifying some aspects of diversity on which liberals and conservatives agree," said Daniel Cervone, UIC professor of psychology and study co-author. "Breaking the concept of 'diversity' into parts and identifying those parts on which people agree could be one small step toward reducing political polarization."

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Matt Motyl of Facebook is a co-author on the report.

Neuroscientists posit that brain region is a key locus of learning

PICOWER INSTITUTE AT MIT

Research News

IMAGE: THE LOCUS COERULEUS IS DEEP IN THE BRAIN BUT PROJECTS CIRCUITS THROUGHOUT THE ORGAN. view more 

CREDIT: SUR LAB/ MIT PICOWER INSTITUTE

Small and seemingly specialized, the brain's locus coeruleus (LC) region has been stereotyped for its outsized export of the arousal-stimulating neuromodulator norepinephrine. In a new paper and with a new grant from the National Institutes of Health, an MIT neuroscience lab is making the case that the LC is not just an alarm button but has a more nuanced and multifaceted impact on learning, behavior and mental health than it has been given credit for.

With inputs from more than 100 other brain regions and sophisticated control of where and when it sends out norepinephrine (NE), the LC's tiny population of surprisingly diverse cells may represent an important regulator of learning from reward and punishment, and then applying that experience to optimize behavior, said Mriganka Sur, Newton Professor of Neuroscience in The Picower Institute for Learning and Memory and the Department of Brain and Cognitive Sciences at MIT.

"What was formerly considered a homogenous nucleus exerting global, uniform influence over its many diverse target regions, is now suggested to be a heterogeneous population of NE-releasing cells, potentially exhibiting both spatial and temporal modularity that govern its functions," wrote Sur, postdoc Vincent Breton-Provencher and graduate student Gabrielle Drummond in a review article published last month in Frontiers in Neural Circuits.

The article presents copious emerging evidence from Sur's group and many others, suggesting that that the LC may integrate sensory inputs and internal cognitive states from across the brain to precisely exert its NE-mediated influence to affect actions - by throttling NE to the motor cortex - and the processing of resulting feedback of reward or punishment - by throttling NE to the prefrontal cortex.

To investigate that hypothesis, the team has begun working with a $2.1 million, 5-year NIH grant awarded in April. In this study they are engaging mice in learning tasks where they are cued by tones of varying pitches and volumes. Over the course of training the mice will learn that when a tone is high pitched, pressing a lever will yield a reward and when the tone is low pitched, the correct response would be to not push lest it experience an unpleasant air puff. By varying the tone volume, the experimenters will vary the certainty the mice can feel that they heard the cue correctly.

The hypothesis (borne out by preliminary data) predicts that the NE will matter in multiple crucial ways, Sur said. When the mouse hears the cue tone, if the pitch is low the LC would send less NE via a cadre of neurons to the motor cortex, reflecting the animal's belief that the lever should not be pushed because no reward will be forthcoming. Meanwhile the lower the volume, the less certainty the animal has in its decision. Conversely, a high tone of high volume would send more NE, reflecting the animal's certainty that pushing the lever would produce a reward.

After the mouse has acted, the more surprising the feedback, the more NE it will produce and send via a distinct group to the prefrontal cortex, stimulating greater learning. So for instance, if the mouse hears a faint, high tone and gingerly presses the lever, the surprise of a resulting reward will stimulate a strong output of NE to instruct the prefrontal cortex because its expectations weren't very high. Whenever a mouse guesses wrong and feels an air puff, that will stimulate the strongest NE release to the prefrontal cortex. After such dynamics, Sur's team has observed consistent performance changes on the subsequent trial.

"This is a way by which norepinephrine can be thought of as an arousal signal, but it's also, importantly, in the context of ongoing function a learning signal," Sur said. "It is both an execution signal and a learning signal, for both of which we can describe the actual quantitative relationships."

Not only will the team be measuring the activity of LC-NE neurons, they'll also take them over using optogenetics (in which neurons can be controlled with light), so that they can silence or amplify LC-NE output to show how doing each affects action and learning.

Understanding the true nature of how the LC works could be useful for improving treatments for certain disorders, Sur said. A potential treatment for PTSD, for instance, involves damping receptiveness to NE, but that also promotes drowsiness. A more principled and precise treatment could improve efficacy and reduce those side effects, he said.

"The hope is to affect the anxiety but not make you sleepy, if we understand the targets and theory behind it," Sur said. "That is the hope of basic science for treating disorders--to make things more and more specific, to define the circuits and the specificity of functions that a system is involved in."

Moreover the LC is an early region affected in Alzheimer's disease, he said. Addressing that loss in the right way could help sustain forms of learning and cognition.

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'Golden nail': Quarry near Salzgitter becomes global geological reference point

Research team with Goethe University participation successfully proposes former quarry in Lower Saxony as Global Stratotype Section and Point

GOETHE UNIVERSITY FRANKFURT

Research News

 

IMAGE: SALZGITTER-SALDER: A PERFECT ROCK BOUNDARY SEQUENCE OVER 40 METRES. view more 

CREDIT: PHOTO: SILKE VOIGT, GOETHE UNIVERSITY FRANKFURT

FRANKFURT/HANNOVER. The international team of geoscientists led by Prof. Silke Voigt from the Goethe University Frankfurt, Prof. Ireneusz Walaszczyk from the University of Warsaw and Dr André Bornemann from LBEG have thoroughly investigated 40 metres of the geological strata sequence in the former limestone quarry at Hasselberg. The researchers determined that this is only sequence in the transition between Turonian and Coniacian without gaps and it therefore represents a perfect rock sequence to serve geoscientists from all over the world as a reference for their research - a "Global Stratotype Section and Point (GSSP)" or, in the jargon of geosciences, a "golden nail".

Certain group of bivalve mollusks of the family Inoceramidae, first appeared in the Coniacian, and are found in large numbers in Salder. In Bed 46 of the quarry, the German-Polish scientific team found the oldest appearance of the Inoceramid species Cremnoceramus deformis erectus, which marks the time boundary. Careful studies also revealed other microfossils and a characteristic change in the ratio of the carbon isotopes 12C and 13C, a so-called negative anomaly in the carbon cycle.

"This means that variable geological sequences, such as marine shelf sediments in Mexico or the deep sea in the tropical Atlantic, can now be compared and classified in time," explains Prof. Silke Voigt. "This is important in order to be able to make an exact chronological classification even in the case of incomplete successions and ultimately to see, for example, what the climate was like at a certain time in the past in different places in the world."

Professor Ireneusz Walaszczyk says: "The sequence in Salzgitter-Salder prevails over other candidates, for example from the USA, India, Madagascar, New Zealand and Poland, because we have a perfect rock boundary sequence here over 40 metres, with a well-defined record of events which took place in this interval of geological time."

"The Zechstein Sea left behind massive salt layers in the North German Basin more than 250 million years ago," explains André Bornemann. "The rock layers deposited later exerted pressure on these salt layers, some of which bulged up into large salt domes, deforming younger layers in the process. Salder is located near such a salt dome, so that here the fossil-rich rock layers of the Cretaceous period are steeply upright, resulting in a wonderful profile that is very accessible for scientific investigations. That's why we at LBEG have designated this place as a geotope, and this is one of the most important geopoints of the Harz-Braunschweiger Land-Ostfalen UNESCO Global Geopark."

CAPTION

Layer 46 marks the transition from the Cretaceous Turonian to the Coniacian Age.

CREDIT

Photo and montage: Silke Voigt, Goethe University Frankfurt. Fossil: Walaszczyk et al. (2010)

Background:

In the limestone quarry at Hasselberg near Salder in the north-east of the Salzgitter mountain range, limestone and marl used to be quarried for the cement industry and later for ore processing. Today, it is the location of a well-known biotope and geotope which is the property of the Stiftung Naturlandschaft (Natural Landscape Foundation) and established by the BUND regional association of Lower Saxony. While the care of the quarry site has been entrusted to the Salzgitter district group of BUND, the Harz-Braunschweiger Land-Ostfalen UNESCO Global Geopark looks after the geoscientific part of the quarry. The quarry is not freely accessible for nature conservation reasons, but guided walks are occasionally offered.

90 million years ago, in the second half of the Cretaceous, it was tropically warm on Earth: the ice-free poles ensured high sea levels, and Central Europe consisted of a cluster of islands. In the sea, ammonites developed a tremendous variety of forms, while dinosaurs reigned on land. The first flowering plants began to compete with horsetails and ferns. About 89.39 million years ago, the climate began to cool slightly, sea levels began sink, and a new period in Earth history, the Coniacian, replaced the Turonian.

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Publications:

Voigt S, Püttmann T, Mutterlose J, Bornemann A, Jarvis I, Pearce M, Walaszczyk, I (2021) Reassessment of the Salzgitter-Salder section as a potential stratotype for the Turonian-Coniacian Boundary: stable carbon isotopes and cyclostratigraphy constrained by nannofossils and palynology. Newsl Stratigr, 54/2, 209-228, https://doi.org/10.1127/nos/2020/0615

Walaszczyk, I., Cech, S., Crampton, J.S., Dubicka, Z., Ifrim, C., Jarvis, I., Kennedy, W.J., Lees, J.A., Lodowski, D., Pearce, M. Peryt, D., Sageman, B., Schiøler, P., Todes, J., Uličný, D., Voigt, S., Wiese, F., With contributions by, Linnert, C., Püttmann, T., and Toshimitsu, S. (2021) The Global Boundary Stratotype Section and Point (GSSP) for the base of the Coniacian Stage (Salzgitter-Salder, Germany) and its auxiliary sections (S?upia Nadbrze?na, central Poland; St?eleč, Czech Republic; and El Rosario, NE Mexico). Episodes 2021; 44(2): 129-150l. https://doi.org/10.18814/epiiugs/2020/020072

Tweezers of sound can pick objects up without physical contact

Hemispherical array of ultrasound transducers lifts objects off reflective surfaces

TOKYO METROPOLITAN UNIVERSITY

Research News

 VIDEO: A HEMISPHERICAL ARRAY OF ULTRASOUND TRANSDUCERS WITH PHASE AND AMPLITUDE CONTROL IS DRIVEN TO CREATE AN ACOUSTIC FIELD WHICH CAN TRAP AND LIFT A POLYSTYRENE BALL OFF A REFLECTIVE SURFACE. view more 

CREDIT: TOKYO METROPOLITAN UNIVERSITY

Tokyo, Japan - Researchers from Tokyo Metropolitan University have developed a new technology which allows non-contact manipulation of small objects using sound waves. They used a hemispherical array of ultrasound transducers to generate a 3D acoustic fields which stably trapped and lifted a small polystyrene ball from a reflective surface. Although their technique employs a method similar to laser trapping in biology, adaptable to a wider range of particle sizes and materials.

The ability to move objects without touching them might sound like magic, but in the world of biology and chemistry, technology known as optical trapping has been helping scientists use light to move microscopic objects around for many years. In fact, half of the 2018 Nobel Prize for Physics, awarded to Arthur Ashkin (1922-2020) was in recognition of the remarkable achievements of this technology. But the use of laser light is not without its failings, particularly the limits placed on the properties of the objects which can be moved.

Enter acoustic trapping, an alternative which uses sound instead of optical waves. Sound waves may be applied to a wider range of object sizes and materials, so much so that successful manipulation is possible for millimeter-sized particles. Though they haven't been around for as long as their optical counterparts, acoustic levitation and manipulation show exceptional promise for both lab settings and beyond. But the technical challenges that need to be surmounted are big. In particular, it is not easy to individually and accurately control vast arrays of ultrasound transducers in real-time, and get the right sound fields to lift objects far from the transducers themselves, particularly near surfaces that reflect sound.

Now, Researcher Shota Kondo and Associate Professor Kan Okubo from Tokyo Metropolitan University have come up with a new approach to lift millimeter-sized objects off a reflective surface using a hemispherical array of transducers. Their method of driving the array does not involve complex addressing of individual elements. Instead, they split the array into manageable blocks and use an inverse filter that finds the best phase and amplitude to drive them to make a single trap at some distance from the transducers themselves. By adjusting how they drive the blocks over time, they can change the position of their target field and move the particle they have trapped. Their findings are supported by simulations of the 3D acoustic fields that are created by the arrays, and of course, by their experiments with a polystyrene ball, which speak for themselves (see the video).

Though challenges remain in keeping particles trapped and stable, this exciting new technology promises big advances towards transforming acoustic trapping from a scientific curiosity to a practical tool in the lab and in industry.

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Newly-hatched pterosaurs may have been able to fly

UNIVERSITY OF PORTSMOUTH

Research News

IMAGE: THE ATTACHED IMAGE SHOWS A FLOCK PTERODAUSTRO GUINAZUI. view more 

CREDIT: DR MARK WITTON

Newly-hatched pterosaurs may have been able to fly but their flying abilities may have been different from adult pterosaurs, according to a new study.

Pterosaurs were a group of flying reptiles that lived during the Triassic, Jurassic and Cretaceous Periods (228 to 66 million years ago). Due to the rarity of fossilised pterosaur eggs and embryos, and difficulties distinguishing between hatchlings and small adults, it has been unclear whether newly-hatched pterosaurs were able to fly.

Researchers from the Universities of Portsmouth and Bristol, along with palaeontologist Darren Naish, found that hatchling humerus bones were stronger than those of many adult pterosaurs, indicating that they would have been strong enough for flight.

In the study, published in Scientific Reports, the researchers modelled the flying abilities of hatchlings using previously obtained wing measurements from four established hatchling and embryo fossils from two pterosaur species, Pterodaustro guinazui and Sinopterus dongi. They also compared these wing measurements with those of adults from the same species and compared the strength of the humerus bone, which forms part of the wing, of three hatchlings with those of 22 adult pterosaurs.

Study co-author Dr Mark Witton from the University of Portsmouth said: "Although we've known about pterosaurs for over two centuries, we've only had fossils of their embryos and hatchlings since 2004. We're still trying to understand the early stages of life in these animals. One discussion has centred around whether pterosaurs could fly as hatchlings or, like the vast majority of birds and bats, they had to grow a little before they could take wing.

"We found that these tiny animals - with 25 cm wingspans and bodies that could neatly fit in your hand - were very strong, capable fliers. Their bones were strong enough to sustain flapping and take-off, and their wings were ideally shaped for powered (as opposed to gliding) flight. However, they would not have flown exactly like their parents simply because they were so much smaller: flight capabilities are strongly influenced by size and mass, and so pterosaur hatchlings, being hundreds of times smaller than their parents, were likely slower, more agile fliers than the wide-ranging, but less manoeuvrable adults."

Dr Liz Martin-Silverstone from the University of Bristol's School of Earth Sciences said: "There have been several debates about whether juvenile pterosaurs could fly, but this is the first time it's been studied through a more biomechanical point of view. It's exciting to discover that even though their wings may have been small, they were built in a way that made them strong enough to fly."

The researchers found that while hatchlings had long, narrow wings suited to long-distance flight, their wings were shorter and broader than those of adult pterosaurs, with a larger wing area relative to hatchling mass and body size. These wing dimensions may have made hatchlings less efficient than adult pterosaurs at long-distance travel, but may have resulted in them being more agile fliers, enabling them to suddenly change direction and speed.

The authors speculate that the agile flying style of hatchling pterosaurs may have enabled them to rapidly escape predators and made them better suited to chasing nimbler prey and flying amongst dense vegetation than adult pterosaurs.

Dr Witton said: "That gives us a lot to think about with regard to flying reptile ecology. How independent were the hatchlings from their parents? Did flight style influence habitat choices, and did these change as pterosaurs grew? There's still a lot to learn about the life histories of these animals, but we're confident that, whatever they were doing as they grew up, they were capable of flying from the moment they hatched."

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