Overcoming tab overload

CMU researchers develop tool to better manage browser tabs

CARNEGIE MELLON UNIVERSITY

Research News

 

If you are reading this, chances are you have several other tabs open in your browser that you mean to get to eventually.

Internet browser tabs are a major source of friction on the internet. People love them. People hate them. For some users, tabs bring order and efficiency to their web browsing. For others, they spiral out of control, shrinking at the top of the screen as their numbers expand.

A research team at Carnegie Mellon University recently completed the first in-depth study of browser tabs in more than a decade. They found that many people struggle with tab overload, an underlying reason being that while tabs serve a variety of functions, they often do so poorly.

"Browser tabs are sort of the most basic tools that you use on the internet," said Joseph Chee Chang, a postdoctoral fellow in the School of Computer Science's Human Computer Interaction Institute (HCII) and a member of the research team. "Despite being so ubiquitous, we noticed that people were having all sorts of issues with them."

The team will present their paper, "When the Tab Comes Due: Challenges in the Cost Structure of Browser Tab Usage," at the Association for Computing Machinery's Conference on Human Factors in Computing Systems (CHI 2021), May 8-13.

For the study, the team conducted surveys and interviews with people about their tab use. The study details why people kept tabs open, including using them as reminders or fearing they would have to search for the information again. It also looked at why people closed tabs, knowing that tab overload can strain a person's attention and computer resources. About 25% of the participants in one aspect of the study reported that their browser or computer crashed because they had too many tabs open.

The researchers found that people felt invested in the tabs they had open, making it difficult for them to close the tabs even as they started to feel overwhelmed or ashamed by how many they had open.

Tabs first showed up in web browsers in 2001 and haven't changed much since. The internet, however, has. There is about a billion times more information on the web now than there was 20 years ago. Today, one tab could house an email inbox. Another could be used for a music or video player. Articles stashed away to read later could be in other tabs, as could restaurant reviews or information for an upcoming trip. Add in social media sites, news or other pages used for work or play, and it is easy to have a dozen or more tabs or windows open at any given time.

Tabs, it turns out, aren't the best tool for assisting with complex work and life tasks that people perform on the internet. Their simple list structure makes it difficult for users to jump between sets of tasks throughout the day. And despite people using tabs as an external form of memory, they do not capture the rich structure of their thoughts. Researchers found that while users complained about being overwhelmed by the number of tabs they queued up to work on later, they also didn't want to move them out of sight, as they worried about never going back to them.

"People feared that as soon as something went out of sight, it was gone," said Aniket Kittur, a professor in the HCII and head of the research team. "Fear of this black hole effect was so strong that it compelled people to keep tabs open even as the number became unmanageable."

Tab overload also arises from sense-making and decision tasks that require a person to absorb information from many sources, stitch it together and come to a conclusion. For instance, if someone is researching what camera to buy, that person may search several different reviews, how-to guides and shopping sites to compare models.

"Managing this sort of task is really one of the most important aspects of productivity in our lives," Kittur said. "And the number one tool that everyone uses for it is tabs, even though they don't do a good job."

The team believes that today's browsers do not offer a good tool for managing all the information and tasks people head to the internet for. To fix this, they created Skeema, an extension for the Google Chrome browser that reimagines tabs as tasks.

The extension helps users group their tabs into tasks and then organize, prioritize and switch between them. Skeema uses machine learning to make suggestions for grouping open tabs into tasks and supports nested tasks and complex decision-making.

Users of an early version of the tool significantly reduced the number of tabs and windows they kept open, reported much less stress connected to tabs, and remained more focused on the task at hand. Many of the early beta testers started using the tool daily to manage the tabs and tasks in their lives.

"Our task-centric approach allowed users to manage their browser tabs more efficiently, enabling them to better switch between tasks, reduce tab clutter and create task structures that better reflected their mental models," Chang said. "As our online tasks become increasingly complex, new interfaces and interactions that can merge tab management and task management in a browser will become increasingly important. After 20 years of little innovation, Skeema is a first step toward making tabs work better for users."

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Consumption of pornography is widespread among young Internet users

LUDWIG-MAXIMILIANS-UNIVERSITÄT MÜNCHEN

Research News

 

Nearly four-fifths of 16- and 17-year-olds have encountered pornographic content on the Internet

Pornography is a multibillion-dollar business. Pornographic content is virtually ubiquitous on the Internet, and surveys suggest that 25% of all searches lead to explicit content. Given the size of the market, it's not surprising that young people are drawn to such sites, which are only a couple of clicks away.

Professor Neil Thurman of the Department of Media and Communication (IfKW) at Ludwig-Maximilians-Universitaet (LMU) in Munich, in collaboration with statistician Fabian Obster (Universität der Bundeswehr München), has carried out a study on the use of pornographic sites by young people. Based on a survey involving a sample of 1000 British adolescents, the survey also provides pointers for regulators and legislators in Germany.

Overall, 78% of users between the ages of 16 and 17 reported that they had encountered pornography on the Internet. Moreover, many of them stated that they visited dedicated pornographic websites frequently. Those who participated in the survey admitted that, on average, they had last visited such sites 6 days prior to filling in the questionnaire. And many respondents said they watched porno videos and viewed picture galleries on that very day. Analysis of the responses indicated that adolescents spent an average of 2 hours per month on commercial pornographic websites, almost always accessed on their smartphones or tablets. The survey also revealed that young consumers are also turning to social media portals for access to explicit material. Adolescent users of online pornography are more likely to be male.

Well acquainted with VPNs and the Tor browser

In Germany, the UK, France and Canada, efforts are now underway to regulate access to legal online pornography, and in some cases measures have already been implemented. These include provisions for mandatory age verification prior to the admission of users to such websites. But, according to Thurman's survey, around half of the respondents had used VPNs or the Tor browser. Both tools anonymize connection data, thus allowing country-specific restrictions to be circumvented.

"At present, the online pornography market is highly concentrated. It is dominated by a few global firms. Indeed, only a handful of websites account for the majority of consumption," Thurman says. In the context of measures to protect minors, he therefore suggests that, in additional to country-specific measures, there should also be pressure placed on the major global publishers of pornography, to encourage them to introduce effective age restrictions in all the markets in which they operate. In addition, similar regulations should be applied, as is already happening in the UK, to social-media platforms.

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New study explores functionality in aquatic ecosystems

The functions of water-dominated ecosystems can be considerably influenced and changed by hydrological fluctuation; the varying states of redox-active substances are of crucial importance here

UNIVERSITÄT BAYREUTH

Research News

IMAGE: LEAKAGE OF IRON-RICH GROUNDWATER IN A CATTLE PASTURE. THE RED COLOUR COMES FROM A MIXTURE OF OXIDISED IRON AND CARBON COMPOUNDS, WHICH ARE HIGHLY REACTIVE REDOX PHASES. view more 

CREDIT: PHOTO: STEFAN PEIFFER.

The functions of water-dominated ecosystems can be considerably influenced and changed by hydrological fluctuation. The varying states of redox-active substances are of crucial importance here. Researchers at the University of Bayreuth have discovered this, in cooperation with partners from the Universities of Tübingen and Bristol and the Helmholtz Centre for Environmental Research, Halle-Leipzig. They present their discovery in the journal Nature Geoscience. The new study enables a more precise understanding of the biogeochemical processes that contribute to the degradation of pollutants and the reduction of greenhouse gas emissions.

Reducing the generation of greenhouse gases, storing carbon, removing environmental pollutants such as nitrate, and providing high-quality drinking water - these are important services provided by aquatic ecosystems, such as lakes, streams, marshes, and bogs. The functions of such aquatic ecosystems are closely linked to the cycles of oxygen, nitrogen, carbon, and other elements in nature. It has long been known that elemental cycles are interconnected biogeochemical processes that can be significantly influenced by hydrological fluctuation. Examples of this are fluctuations in the water level of wetlands, peatlands, and groundwater, or even changing flow directions in groundwater.

The research team led by Prof. Dr. Stefan Peiffer at the University of Bayreuth has now succeeded in understanding the dependence of element cycles on hydrological fluctuation more precisely. As numerous laboratory studies have shown, redox-active substances have a key function in this. "Anyone who has ever trudged through a swamp or rummaged in the sand of a swimming lake will have noticed these substances because of their variety of colour. In a very confined space, colour shades alternate from deep black to grey and brown to light red. What is behind this, is an interplay of microbiological and chemical processes in which electrons are being transferred. In research, we call them redox reactions," says Peiffer.

A comparatively simple form of redox reaction is respiration in humans and animals. Carbon is oxidised by oxygen to form carbon dioxide. In the microbially driven redox reactions that take place in a swamp, for example, the role of oxygen is taken over by a variety of redox-active substances - iron, sulphur, and manganese compounds or humic substances. The life span of these substances is very short, but they show a very strong tendency to engage in redox reactions. They are therefore called "redox-active metastable phases" (RAMPs). Due to their high reactivity, RAMPs play a major role in elemental cycles in ecosystems. For example, they are able to degrade pollutants such as nitrates or various other organic chemicals.

One reason for the short lifespan of RAMPs is the constant change between electron-donating and electron-accepting conditions. The study, published in Nature Geoscience, comes to a conclusion decisive for ecological and environmental research. The dynamics of the redox reactivity of RAMPs is triggered by hydrological fluctuations that occur in shore zones, in wetlands, in waterlogged soils, in rice-growing soils or at the surface of sediments in lakes and rivers. These small-scale biogeochemical reactions, in turn, influence the large-scale reactions of the ecosystem, for example, the amount of greenhouse gases released into the atmosphere. This makes it understandable for the first time how hydrological fluctuations, for example fluctuating water levels, affect elemental cycles in nature, and thus the functioning of ecosystems.

"Our study shows that biogeochemical reactions on a scale of only a few micrometres form an important crux between two large-scale processes: between hydrological fluctuations on the one hand, and ecosystem functions on the other. Our new findings will therefore help to better predict pollutant degradation in aquatic ecosystems in future. The consequences of climate change for carbon and nitrogen conversion in these ecosystems may also be more accurately assessed in future," says Peiffer.

CAPTION

Wetland in the National Forest in England.

CREDIT

Photo: Andreas Kappler.

 

Why is COVID-19 so hard to treat? Growing evidence points to unique infectious profile

TRINITY COLLEGE DUBLIN

Research News

 

A comprehensive review into what we know about COVID-19 and the way it functions suggests the virus has a unique infectious profile, which explains why it can be so hard to treat and why some people experience so-called "long-COVID", struggling with significant health issues months after infection.

There is growing evidence that the virus infects both the upper and lower respiratory tracts - unlike "low pathogenic" human coronavirus sub-species, which typically settle in the upper respiratory tract and cause cold-like symptoms, or "high pathogenic" viruses such as those that cause SARS and ARDS, which typically settle in the lower respiratory tract.

Additionally, more frequent multi-organ impacts, and blood clots, and an unusual immune-inflammatory response not commonly associated with other, similar viruses, mean that COVID-19 has evolved a uniquely challenging set of characteristics.

While animal and experimental models imply an overly aggressive immune-inflammation response is a key driver, it seems things work differently in humans: although inflammation is a factor it is a unique dysregulation of the immune response that causes our bodies to mismanage the way they fight the virus.

This may explain why some people experience "long-COVID" and suffer severe lung damage after infection.

Ignacio Martin-Loeches, Clinical Professor in Trinity College Dublin's School of Medicine, and Consultant in Intensive Care Medicine at St James's Hospital, is a co-author of the review just published in leading medical journal, The Lancet. He said:

"The emergence of severe acute respiratory syndrome coronavirus two (SARS-CoV-2), which causes COVID-19, has resulted in a health crisis not witnessed since the 1918 Spanish flu pandemic. Tragically, millions around the world have died already.

"Despite international focus on the virus, we are only just beginning to understand its intricacies. Based on growing evidence we propose that COVID-19 should be perceived as a new entity with a previously unknown infectious profile. It has its own characteristics and distinct pathophysiology and we need to be aware of this when treating people.

"That doesn't mean we should abandon existing best-practice treatments that are based on our knowledge of other human coronaviruses, but an unbiased, gradual assembly of the key COVID-19 puzzle pieces for different patient cohorts - based on sex, age, ethnicity, pre-existing comorbidities - is what is need to modify the existing treatment guidelines, subsequently providing the most adequate care to COVID-19 patients."

The review article was produced by the European Group on Immunology of Sepsis (EGIS) in which Professor Martin-Loeches is one of the funding members. EGIS is a multidisciplinary group of scientists and doctors with special interest in severe infection in patients admitted to ICU.

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Can federated learning save the world?

UNIVERSITY OF CAMBRIDGE

Research News

 

Training the artificial intelligence models that underpin web search engines, power smart assistants and enable driverless cars, consumes megawatts of energy and generates worrying carbon dioxide emissions. But new ways of training these models are proven to be greener.

Artificial intelligence models are used increasingly widely in today's world. Many carry out natural language processing tasks - such as language translation, predictive text and email spam filters. They are also used to empower smart assistants such as Siri and Alexa to 'talk' to us, and to operate driverless cars.

But to function well these models have to be trained on large sets of data, a process that includes carrying out many mathematical operations for every piece of data they are fed. And the data sets they are being trained on are getting ever larger: one recent natural language processing model was trained on a data set of 40 billion words.

As a result, the energy consumed by the training process is soaring. Most AI models are trained on specialised hardware in large data centres. According to a recent paper in the journal Science, the total amount of energy consumed by data centres made up about 1% of global energy use over the past decade - equalling roughly 18 million US homes. And in 2019, a group of researchers at the University of Massachusetts estimated that training one large AI model used in natural language processing could generate around the same amount of CO2 emissions as five cars would generate over their total lifetime.

Concerned by this, researchers at the University of Cambridge set out to investigate more energy-efficient approaches to training AI models. Working with collaborators at the University of Oxford, University College London, and Avignon Université, they explored the environmental impact of a different form of training - called federated learning - and discovered that it had a significantly greener impact. Instead of training the models in data centres, federated learning involves training models across a large number of individual machines. The researchers found that this can lead to lower carbon emissions than traditional learning.

Senior Lecturer Dr Nic Lane explains how it works when the training is performed not inside large data centres but over thousands of mobile devices - such as smartphones - where the data is usually collected by the phone users themselves.

"An example of an application currently using federated learning is the next-word prediction in mobile phones," he says. "Each smartphone trains a local model to predict which word the user will type next, based on their previous text messages. Once trained, these local models are then sent to a server. There, they are aggregated into a final model that will then be sent back to all users."

And this method has important privacy benefits as well as environmental benefits, points out Dr Pedro Porto Buarque De Gusmao, a postdoctoral researcher working with Dr Lane.

"Users might not want to share the content of their texts with a third party," he explains. "In federated learning, we can keep data local and use the collective power of millions of mobile devices together to train AI models without users' raw data ever leaving the phone."

"And besides these privacy-related gains," says Dr Lane, "in our recent research, we have shown that federated learning can also have a positive impact in reducing carbon emissions.

"Although smartphones have much less processing power than the hardware accelerators used in data centres, they don't require as much cooling power as the accelerators do. That's the benefit of distributing the training of models across a wide pool of devices."

The researchers recently co-authored a paper on this called 'Can Federated Learning save the planet?' and will be discussing their findings at an international research conference, the Flower Summit 2021, on 11 May.

In their paper, they offer the first-ever systematic study of the carbon footprint of federated learning. They measured the carbon footprint of a federated learning setup by training two models -- one in image classification, the other in speech recognition - using a server and two chipsets popular in the simple devices targeted by federated methods. They recorded the energy consumption during training, and how it might vary depending on where in the world the chipsets and server were located.

They found that while there was a difference between CO2 emission factors among countries, federated learning under many common application settings was reliably 'cleaner' than centralised training.

Training a model to classify images in a large image dataset, they found any federated learning setup in France emitted less CO2 than any centralised setup in both China and the US. And in training the speech recognition model, federated learning was more efficient than centralised training in any country.

Such results are further supported by an expanded set of experiments in a follow-up study ('A first look into the carbon footprint of federated learning') by the same lab that explores an even wider variety of data sets and AI models. And this research also provides the beginnings of necessary formalism and algorithmic foundation of even lower carbon emissions for federated learning in the future.

Based on their research, the researchers have made available a first-of-its-kind 'Federated Learning Carbon Calculator' so that the public and other researchers can estimate how much CO2 is produced by any given pool of devices. It allows users to detail the number and type of devices they are using, which country they are in, which datasets and upload/download speeds they are using and the number of times each device will train on its own data before sending its model for aggregation.

They also offer a similar calculator for estimating the carbon emissions of centralised machine learning.

"The development and usage of AI is playing an increasing role in the tragedy that is climate change," says Dr Lane, "and this problem will only worsen as this technology continues to proliferate through society. We urgently need to address this which is why we are keen to share our findings showing that federated learning methods can produce less CO2 than data centres under important application scenarios.

"But even more importantly, our research also shines a light as to how federated learning should evolve towards being even more broadly environmentally friendly. Decentralized methods like this will be key in the invention of future sustainable forms of AI in the years ahead."

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Why hotter clocks are more accurate

LANCASTER UNIVERSITY

Research News

 

IMAGE: CLOCKS PERVADE EVERY ASPECT OF LIFE, FROM THE ATOMIC CLOCKS THAT UNDERLIE SATELLITE NAVIGATION TO THE CELLULAR CLOCKS INSIDE OUR BODIES. view more 

CREDIT: LANCASTER UNIVERSITY

A new experiment shows that the more energy consumed by a clock, the more accurate its timekeeping.

Clocks pervade every aspect of life, from the atomic clocks that underlie satellite navigation to the cellular clocks inside our bodies. All of them consume energy and release heat. A kitchen clock, for example, does this by using up its battery. Generally the most accurate clocks require the most energy, which hints at a fundamental connection between energy consumption and accuracy. This is what an international team of scientists from Lancaster, Oxford, and Vienna set out to test.

To do this, they built a particularly simple clock, consisting of a vibrating ultra-thin membrane, tens of nanometers thick and 1.5 millimeters long, incorporated into an electronic circuit. Each oscillation of the membrane generated one electrical tick. The ingenious aspect of this design is that it is powered simply by heating the membrane, while the complete flow of energy through the clock can be measured electrically.

The scientists found that the more heat they supplied, the more accurately the clock ran. In fact, the accuracy was directly proportional to the heat released. To make the clock twice as accurate, they needed to supply twice as much heat.

The experimental team consisted of Dr Edward Laird at Lancaster University, Professor Marcus Huber at Atominstitut, TUWien, Dr Paul Erker and Dr Yelena Guryanova at the Institute for Quantum Optics and Quantum Information (IQOQI), and Dr Natalia Ares, Dr Anna Pearson and Professor Andrew Briggs from Oxford.

Their study, published in Physical Review X, is the first time that a measurement has been made of the entropy - or heat loss - generated by a minimal clock.

Understanding the thermodynamic cost involved in timekeeping is a central step along the way in the development of future technologies, and understanding and testing thermodynamics as systems approach the quantum realm.

It also shows a similarity between the operation of a clock and a steam engine. With a steam engine there is fundamental constraint on how much heat we must supply to do a desired amount of work. This constraint is the famous Second Law of Thermodynamics which is central to modern engineering. What this experiment suggests is that clocks, like engines, are constrained by the Second Law, with their output being accurate ticks instead of mechanical work.

Dr Edward Laird of Lancaster University said: "The subject of thermodynamics, which incorporates the most fundamental principles of nature, tells us that there are two types of machine that we cannot operate without releasing heat. One is the mechanical engine, which releases heat to do work, and the other is the computer memory, which releases heat when it rewrites itself. This experiment - in conjunction with other work - suggests that clocks are also limited by thermodynamics. It also poses an intriguing question: are all possible clocks limited in this way, or is it just a property of the ones we have studied?"

Interestingly, many everyday clocks have an efficiency that is close to what the scientists' analysis predicts. For example, their formula predicts that a wristwatch whose accuracy per tick is one part in ten million must consume at least a microwatt of power. In fact, a basic wristwatch usually consumes only a few times this amount. The laws of thermodynamics, discovered in the nineteenth century, are still finding new applications today.

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Losing an only child is more devastating than losing a spouse, according to study of Chinese parents

With millions of one-child families in China, study highlights distress experienced after loss

NEW YORK UNIVERSITY

Research News

 

Which wound cuts deeper: the loss of an only child or loss of a spouse? A new study led by researchers at NYU Rory Meyers College of Nursing and Fudan University suggests that Chinese parents find the loss of an only child to be approximately 1.3 times as psychologically distressing than the loss of a spouse. The findings are published in the journal Aging & Mental Health.

Older adults in China rely heavily on family support, particularly from their adult children. Filial piety--the Confucian idea describing a respect for one's parents and responsibility for adult children to care for their parents as they age--is a central value in traditional Chinese culture.

In the 1970s, China introduced a one-child policy to slow the population growth, resulting in hundreds of millions of families with only children. While the policy ended in 2016, its consequences will be felt for decades, particularly for families who experience the loss of a child.

"The death of a child has been recognized as one of the most challenging and traumatic events for a parent," said Bei Wu, PhD, Dean's Professor in Global Health at NYU Rory Meyers College of Nursing and co-director of the NYU Aging Incubator, as well as the study's senior author. "Within the cultural context of China, the death of an only child is devastating not only due to the emotional loss, but also the loss of financial and instrumental support that is critical to older adults."

The death of a spouse is also recognized as a distressing life event, forcing older adults to navigate both the emotional loss and the shattering of a married couple's social and economic circumstances. In this study, Wu and her colleagues wanted to examine whether the loss of a spouse had a similar impact on psychological well-being as the loss of an only child, and whether the presence of one mitigated the absence of the other.

The researchers analyzed data from a 2013 survey conducted in Shanghai involving more than 1,100 adults, including 128 parents who lost their only child. The survey evaluated the impact of the loss of a spouse or child on participants' psychological well-being, including depression, loneliness, and life satisfaction.

They found that adults who lost their only child but have a living spouse had more psychological distress than those who lost their spouse but have a living child. This effect appeared to be stronger in women than in men.

Losing an only child resulted in 1.37 times the level of loneliness and 1.51 times the level depression as losing a spouse, and life satisfaction was 1.14 times worse for those who lost an only child vs. their spouse. Adults whose children and spouse were both alive had better psychological well-being than those who experienced loss.

"Our findings demonstrate that the loss of an only child carries more psychological weight than the loss of a spouse in Chinese culture," said Wu.

Wu and her colleagues recommend increasing access to professional mental health services for adults who experience loss, as well as developing culturally relevant interventions to address social isolation and loneliness among older Chinese adults.

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Wu collaborated on this study with Yan Liang and Hong Liang of Fudan University, Hanzhang Xu of Duke University, and Feinian Chen of the University of Maryland.

About NYU Rory Meyers College of Nursing (@NYUNursing)

NYU Rory Meyers College of Nursing is a global leader in nursing and health. Founded in 1932, the College offers B.S., M.S., DNP and Ph.D. degree programs providing the educational foundation to prepare the next generation of nursing leaders and researchers. NYU Meyers has several programs that are highly ranked by U.S. News & World Report and is among the top 10 nursing schools receiving NIH funding, thanks to its research mission and commitment to innovative approaches to health care worldwide.

New research sets stage for development of salmonella vaccine

UNIVERSITY OF FLORIDA

Research News

 

With the COVID-19 vaccines on many people's minds, some may be surprised to learn that we do not yet have vaccines for many common infectious diseases.

Take salmonella, for example, which can infect people through contaminated food, water and animals. According to the World Health Organization, non-typhoidal salmonella infection affects more than 95 million people globally each year, leading to an estimated 2 million deaths annually. There is no approved vaccine for salmonella in humans, and some strains are antibiotic-resistant.

But just as scientists spent decades doing the basic research that made the eventual development of the COVID-19 vaccines possible, University of Florida researchers led by Mariola Edelmann in the department of microbiology and cell science, UF/IFAS College of Agricultural and Life Sciences, are laying the groundwork for an effective vaccine for salmonella and other hard-to-treat bacterial infections. In their study supported by the National Institutes of Health and published in PLOS Pathogens, the UF/IFAS scientists demonstrate a novel approach to triggering immunity against salmonella.

This approach takes advantage of how cells communicate with each other, said Winnie Hui, first author of the study, which was conducted while she was a doctoral candidate in microbiology and cell science.

"Cells communicate with each other through particles called extracellular vesicles or EVs. Think of these like molecular telephones that let cells talk to each other. We wanted to know if some of those messages included information related to immune response," said Hui, who graduated from the UF/IFAS College of Agricultural and Life Sciences in 2019 and is now a postdoctoral researcher in the UF College of Medicine, division of rheumatology and clinical immunology.

"Host EVs have not been previously studied in the context of fighting enteric bacterial infections, so that is part of what makes our approach new and adds to the field," said Edelmann, senior author on the study, Hui's dissertation director and an assistant professor of microbiology and cell science.

Edelmann hypothesized that a specific type of EVs called exosomes were part of the immune response against salmonella and may one day hold the key to developing a vaccine.

To test their idea, the research team took exosomes from white blood cells infected with salmonella. Inside those exosomes, which measure just a few dozen nanometers across, they found salmonella antigens, which are bits of salmonella protein known to trigger an immune response.

Next, the researchers wanted to know if these exosomes might function as a vaccine, helping the body build up its defenses against salmonella, said Lisa Emerson, one of the study's co-authors and a doctoral student in Edelmann's laboratory.

"We put the exosomes in 'nanobubbles' that the mice inhaled. Later, we ran tests to see how their immune systems responded," said Emerson, who is in the UF/IFAS College of Agricultural and Life Sciences.

The researchers found that after they introduced the exosomes containing salmonella antigens, the exosomes localized to tissues that produce mucous, activating specific cells at these sites. Weeks later, mice developed antibodies against salmonella and specific cellular immune responses, which typically target this bacterium for elimination. For the researchers, this is a promising result.

"There are two types of immune responses generated when our bodies encounter a pathogen. The first one is called innate immunity, which is an immediate response to an infection, but it is also less specific. The other response is called adaptive immunity, and this protective response is specifically tailored to a given pathogen, but it also takes longer to develop. Exosomes generated by infected white blood cells stimulated both of these responses in animals," said Hui.

While these results show promise, more research will be needed before we have a salmonella vaccine that works in humans, Hui said.

"Our study has identified a novel role of exosomes in the protective responses against salmonella, but we also think that exosomes can find broader applications for other intestinal infections and beyond," Edelmann said.

"Exosomes have this unique capability to encapsulate precious cargo while enabling its targeted delivery to tissue of interest. For many conditions and infections, this precise delivery of therapeutic payload is what makes a difference, and we are currently also evaluating exosomes in delivering cargo to other tissues of choice," said Edelmannn whose work is supported by several federal funds focused on the roles of extracellular vesicles in bacterial infections and disease and host-directed therapies against intestinal infections.

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Archaeologists pinpoint population for the Greater Angkor region

Study designed at the University of Oregon provided a foundation that drew new information from lidar imagery, machine learning, archaeological and historical data

UNIVERSITY OF OREGON

Research News

 

IMAGE: A PAIR OF CONTEMPORARY CAMBODIAN HOUSES: THE HOUSE IN THE BACKGROUND IS MADE FROM WOOD AND MODERN MATERIALS. THE HOUSE IN THE FOREGROUND WAS BUILT TRADITIONALLY FROM ORGANIC MATERIALS SUCH... view more 

CREDIT: PHOTO BY ALISON CARTER

EUGENE, Ore. -- May 7, 2021 -- Long-running archaeological research, boosted by airborne lidar sensing and machine-learning algorithms, finds that Cambodia's Greater Angkor region was home to 700,000-900,000 people.

The sprawling city, which thrived from the 9th to 15th centuries, has slowly revealed its forest-hidden past to archaeologists, but its total population has been a mystery.

The new estimate, made possible by a study designed at the University of Oregon, is the first for the entire 3,000-square-kilometer mix of urban and rural landscape. The findings published May 7 in the journal Science Advances.

The finding is vital for potentially helping cities under pressure of climate change, said co-author Roland Fletcher of the University of Sydney and director of the Angkor Research Program, a collaboration with Cambodia's Authority for the Protection of the Site and Management of the Region of Angkor.

"We predominantly are living in giant low-density cities around the world that are similar to Angkor, which displayed serious vulnerability to severe climate change," Fletcher said. "We really need to know the mechanics of how Angkor worked and what people were doing to get some idea of how referable those experiences are to the risks that we face in our future."

With the combined data, including that from several decades of research by international and Cambodian researchers, the new study revealed population details of Angkor's ceremonial city center, the metropolis extending outward like modern suburbia and embankments incorporating agricultural areas. Angkor was a low-density city, with its population spread out across a wide area.

An initial population estimate was for 750,000 residents in an area of 1,000-square kilometers around central Angkor, Fletcher said. In this area are stone religious temples, including Angkor Wat that attract tourists.

Beyond the stone temples of central Angkor were homes and locations of supporting structures, all made of organic materials reclaimed by the jungle, said UO archaeologist Alison K. Carter, an expert in fine-grain archaeological research who has conducted fieldwork in Cambodia since 2005.

Carter was co-lead author with Sarah Klassen, formerly a postdoctoral researcher at the University of British Columbia. The two planned and designed the study while Klassen was a visiting scholar at the UO with support from the Office of International Affairs' Global Oregon Faculty Collaboration Fund. In all, 14 long-active Angkor researchers collaborated.

Klassen brought machine-learning to the project, deploying a multilayered statistical analysis that merged data from historical archives and maps with details obtained of lidar scans of the region in a project led by co-author Damian Evans of the French Institute of Asian Studies, in 2012 and 2015.

Lidar, which is short for light detection and ranging, is done by sending laser pulses groundward from aircraft. It captures details of ground by ignoring ground clutter such as forests. The new data, Klassen said, "really transformed our understanding of the landscape."

Lidar documented and mapped 20,000 features not seen before, adding to a previous database of 5,000 locations, said Klassen, now a postdoctoral researcher at the University of Leiden.

"When you are on the ground in the main parts of the city center it is quite forested," Carter said. "As you walk around you can tell there is something in the landscape around you, but you cannot see anything clearly. Lidar gave us a beautiful grid of mounds and depressions, which we think were little ponds."

As initial lidar images were being transmitted, researchers at the Angkor field station stayed up into the early morning hours to watch, Fletcher said.

"It was absolutely fabulous," he said. "We had earlier radar data, but the amount of new information was staggering, especially because the lidar images captured the entire region in great detail."

The new data have been organized into different periods of Angkor's growth, particularly in the lifetimes of kings who were most influential to infrastructure changes, said Carter, who heads the UO's Southeast Asian Archeology Lab.

Lidar showed where houses, which had been built on mounds and elevated on posts, had stood. Researchers estimated that five people lived in each household and extrapolated that data to assess the region's total population.

"We looked at the growth of the city of Angkor over time," Carter said. "We found that different parts of the city grew in different ways. The way we think about population growth in cities and suburbs today is probably the same for Angkor."

The study's findings enhance the "comparative understanding of premodern urbanism," said co-author Miriam T. Stark, director of the Center for Southeast Asian Studies at the University of Hawaii at Manoa.

"Studying Angkor's population is important for envisioning the future's urbanism with respect to global climate change," Stark said. "Angkor was a tropical city that persisted through centuries of political and climatic volatility. Tracking its history and tipping point could help urban planners understand some kinds of constraints that face increasing numbers of the world's cities."

Klassen's machine learning contributions initially were published in a 2018 study in PLOS ONE.

"In this new paper," she said, "we introduced statistical learning paradigms and our archaeological case study and dataset. We then explored four classical mathematical approaches to find statistically significant predictors to date temples built in different locations in the region."

That led to a historical model for temples built between the modern-era years of 821-1149 within an absolute average error of 49-66 years.

"This was critical for our study, because it allowed us to see how the metropolitan area developed in comparison to the civic-ceremonial centers," Klassen said. "It also allowed us to estimate populations connected to the temples and see how those population changed over time."

Population information paves the way for better understanding Angkor's economics and resilience, said co-author Christophe Pottier of the French Institute of Asian Studies, who has researched the site for 30 years.

Periods of growth covered in the new study occurred between 770 and 1300.

Future research, Fletcher said, will more deeply examine the expansion of population clusters.

"What was the population of Angkor prior to this sample period? We have to get below all of the current structures with archaeology to predict and model earlier periods," he said.

Klassen and Carter's contributions are crucial to future research, Fletcher said.

Several of the new study's co-authors, including Carter, Evans and Stark, and other collaborators have questioned the conception that Angkor depopulated quickly due to climate pressures in the 15th century.

"We can tell from our archaeological data that that were still people on the landscape, and there is evidence of modifications being made to temples into the 16th century," Carter said. "Our work isn't really designed to answer the timing question for the shift of population away from this area, but it probably happened much slower than long thought."

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Several organizations funded the research, including the Rust Family Foundation, Social Sciences and Humanities Research Council of Canada, a National Science Foundation Doctoral Dissertation Research Improvement Award, the American Council of Learned Societies-Robert H. N. Ho Family Foundation Program in Buddhist Studies, Australian Research Council and European Research Council.

Links:

Paper in Science Advances: https://advances.sciencemag.org/content/7/19/eabf8441

Conversation essay by Carter and Klassen: https://theconversation.com/a-metropolis-arose-in-medieval-cambodia-new-research-shows-how-many-people-lived-in-the-angkor-empire-over-time-157573

About Alison Carter: https://anthropology.uoregon.edu/profile/acarter4/

Carter's Southeast Asian Archaeology Lab: https://blogs.uoregon.edu/acarter4/

Department of Anthropology: https://anthropology.uoregon.edu/

Angkor Wat digs yield new clues to its civilization's decline: https://around.uoregon.edu/content/angkor-wat-digs-yield-new-clues-its-civilizations-decline

About Sarah Klassen: https://www.universiteitleiden.nl/en/staffmembers/sarah-klassen#tab-2

 

New study examines social network's relation to binge drinking among adults

INDIANA UNIVERSITY

Research News

 

IMAGE: HANK GREEN view more 

CREDIT: INDIANA UNIVERSITY

For some people, social gatherings can be a time to imbibe. And for some, that can turn into a time to overindulge. But how do your neighborhood and your social network affect binge drinking?

Along with colleagues at the RAND corporation in Santa Monica, Indiana University researcher Hank Green examined how neighborhood and social network characteristics were related to adult binge drinking. He and his co-authors found that both factors play a role in how much someone drinks, information that can help us better understand binge drinking among adults.

The study was published in the journal Health and Place, indexed in Science Direct and PubMed.

"Adults living in cohesive neighborhoods where people get along, help and look out for one another had a lower likelihood of any binge drinking at all compared to those living in less cohesive neighborhoods," the co-authors point out.

"Living in a highly cohesive neighborhood may impact social norms and constrain behavior in such a way that binge drinking is very unlikely, even if the opportunity to drink arises," Green said.

The researchers also found that, for those who live in neighborhoods they consider safe and orderly, and who have a more interconnected social network, the likelihood of social drinking increases, and drinking heavily might occur in those social drinking situations, regardless of how cohesive they find their neighborhood to be. However, the study also found that those neighborhood and network factors also restrict how often someone binge-drinks, probably through social control processes such as friends and neighbors looking out for each other or commenting on someone's drinking, etc.

"We also found that binge drinking was more likely among adults who lived in orderly neighborhoods and who had denser social networks, but reported lower neighborhood cohesion," said Green, associate professor at the IU School of Public Health-Bloomington.

In neighborhoods ranked by study participants as disordered, unsafe, and lacking cohesion, neighborhood factors lose their overall impact. Social networks tend to take over the role of social control, according to the study. In these types of neighborhoods, it's people with more interconnected social networks who binge less often.

Researchers utilized online surveys from adults ages 30-80 drawn randomly from the RAND American Life Panel. The main predictor variables were neighborhood cohesion (do neighbors help neighbors, do neighbors get along); neighborhood order (my neighborhood is clean, safe); and social network density. Associations of these measures with past month binge drinking (any, number of days) were examined, controlling for demographic characteristics.

Green said the study could help inform intervention practices such as cognitive behavioral therapy because those approaches already focus on identifying people and places that trigger binge drinking and addressing those triggers with behavioral changes. Indirectly, Green said, the study suggests that those interventions could also focus on people and places that discourage binge drinking or facilitate less frequent binge drinking and better drinking choices. Those interventions could also consider a broader definition of "place" that moves beyond a specific location to consider how larger areas like neighborhoods might impact drinking.

"Because neighborhood and social network factors work in tandem to affect the likelihood of binge drinking and the frequency of binge drinking, interventions for problem drinking should incorporate both of these aspects to make them more effective," Green said.

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The study was funded by ongoing National Institutes of Health grants to explore how social networks impact adult health.

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