Hexbyte Glen Cove Time-expanded phase-sensitive optical time-domain reflectometry thumbnail

Hexbyte Glen Cove Time-expanded phase-sensitive optical time-domain reflectometry

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(a) Working principle of the TE-?OTDR technique. The fiber under test is probed by an optical frequency comb with a tooth spacing and a random spectral phase profile. The impulse response of the fiber is encoded on the backscattered signal generated by the propagation of the probe comb. This signal is beaten with a local oscillator, which is another optical frequency comb with the same random spectral phase profile. The LO and the probe comb are composed of the same number of lines, but the line spacing of the LO is slightly higher by an amount . The detection stage consists in a balanced photodetector followed by an electrical low-pass filter. The beating between lines of the probe comb and the neighboring lines of the LO comb results in a radiofrequency comb with a tooth spacing that is given by . This entails a down-conversion of the optical bandwidth, being the compression factor CF the ratio between and . Alternatively, the above process can be understood in the time domain as a large time expansion of the detected signal. (b) Temperature map of a hot point with 2 cm of length measured by the TE-OTDR scheme. A perturbation of 0.2 Hz is recovered. (c) Dynamic strain map around a 4 cm of length obtained by means of the range-extended TE-OTDR scheme. A perturbation of 5 Hz is recovered in this case. Credit: Miguel Soriano-Amat, Hugo F. Martins, Vicente Durán, Luis Costa, Sonia Martin-Lopez, Miguel Gonzalez-Herraez and María R. Fernández-Ruiz

Distributed optical fiber sensing (DOFS) is currently a mature technology that allows ‘transforming’ a conventional fiber optic into a continuous array of individual sensors, which are distributed along its length. Between the panoply of techniques developed in the field of DOFS, those based on phase-sensitive optical time-domain reflectometry (ΦOTDR) have gained a great deal of attention, mainly due to their ability to measure strain and temperature perturbations in real time. These unique features, along with other advantages of distributed sensors (reduced weight, electromagnetic immunity and small size) make ΦOTDR sensors an excellent solution for monitoring large infrastructures (like bridges and pipelines), especially when considering that their cost scales inversely to the number of sensing points, and its resolution can achieve a few meters.

In a new paper published in Light Science & Applications, a team of scientists from the University of Alcalá, University Jaume I and the Spanish Research Council (CSIC) presents a novel fiber optic interrogator to conduct ΦOTDR. It is based on a well-known interferometric technique that employs two mutually coherent optical frequency combs. This new interrogator allows strain and/or temperature sensing with resolutions on the cm scale over up to 1 km range (i.e., it provides >104 sensing points distributed along the ). In view of the reported results, this approach opens up the door for cost-effective DOFS in short range and high-resolution applications, such as structure health monitoring of aerospace components and wellbore production surveillance, which to date have a prohibitive cost.

The technique presented in the paper, called time-extended ΦOTDR (TE-ΦOTDR), relies on the use of a smartly engineered ultra-dense optical frequency comb to probe a sensing fiber. A weak return signal is then originated by the elastic scattering experienced by the light. This signal is detected by making it interfere with a second comb, which has a bandwidth and spectral phase coding similar to that of the probe, but a different tooth spacing. The result is a multi-heterodyne interference that produces a “time extension” of the detected signals (see Figure). In the frequency domain, this process can be understood as a frequency ‘down-conversion’ (an optical-to-electrical mapping). In the dual-comb scheme developed for DOFS, both combs are generated from the same continuous wave laser, thanks to a couple of electro-optical modulators driven by a single arbitrary waveform generator.

Some remarkable features of this scheme are: (i) the flexibility in the design of the combs, which allows the user to achieve the targeted performance for the sensor; (ii) the reduced detection bandwidth (in the sub-megahertz regime for centimeter resolution over 200 meters), which is a consequence of the time-extension experienced by the detected signals; and (iii) the capability of maximizing the power injected into the sensing fiber. This last feature is fundamental to carry out real distributed sensing, given the extreme weakness of the elastic scattering phenomenon. By introducing a controlled random phase profile in the generated combs, the peak power of the optical signals can be minimized, while preserving a high average power to improve the sensor’s signal to noise ratio. In addition, the encoded phase is automatically demodulated upon detection, requiring no further post-processing.

“The sensing scheme based on a conventional dual-comb scheme allows us to reach cm-scale resolutions over sensing ranges of a few hundreds of meters, while keeping a measurement rate of tens of hertz. In the paper, we also introduce a strategy to significantly extend the sensing range without reducing the acoustic sampling rate. The basic idea is to employ two frequency combs with very dissimilar tooth spacing, so the generated time signals have quasi-integer-ratio periods. This scheme, previously applied to the field of spectroscopy, makes it possible to measure fibers up to 1 km length with a spatial resolution of 4 cm. This means 25,000 individual sensing points along the fiber. This performance improvement is at the cost of increasing to some extent the detection bandwidth (up to a few megahertz), as well as the complexity of the processing algorithm, although still retaining the fundamental advantages of the method.”

“The presented techniques expose a completely new operation arena for dynamic ΦOTDR-based sensors, which was limited to fields requiring sensing along tens of kilometers and meter-scale resolutions to arise as a worthwhile solution. The results demonstrated in the paper are a promising step to design distributed sensor providing fast acquisition speed, small detection bandwidth and sharp spatial resolution,” they added.



More information:
Miguel Soriano-Amat et al, Time-expanded phase-sensitive optical time-domain reflectometry, Light: Science & Applications (2021). DOI: 10.1038/s41377-021-00490-0

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Time-expanded phase-sensitive optical time-domain reflectometry (2021, March 23)
retrieved 23 March 2021
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Hexbyte Glen Cove Researchers show where and how plants detect the nutrient potassium thumbnail

Hexbyte Glen Cove Researchers show where and how plants detect the nutrient potassium

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Hexbyte Glen Cove Research uncovers a critical factor in the assembly of cell division machinery in bacteria thumbnail

Hexbyte Glen Cove Research uncovers a critical factor in the assembly of cell division machinery in bacteria

Hexbyte Glen Cove

sepH is required for sporulation septation in Streptomyces venezuelae. (A) Schematic illustrating the multicellular life style of Streptomyces including the two FtsZ-dependent modes of cell division that occur in vegetative and sporogenic hyphae: cross-wall formation and sporulation septation. (B) Schematic of the predicted SepH domain organization including the N-terminal DUF3071 domain containing a helix-turn-helix (HTH) motif and the unstructured C-terminal domain. Numbers indicate corresponding amino acid positions. (C) Cryo-scanning electron micrographs of sporogenic hyphae from wild-type (WT) S. venezuelae, the ΔsepH mutant (SV56), and the complemented mutant strain ΔsepH/sepH+ (MB747). Scale bars: 2 μm. (D) Subcellular co-localization of fluorescently labeled FtsZ (FtsZ-mCherry) and SepH (SepH-YPet) in vegetative and sporulating hyphae. Fluorescent gene fusions were expressed in the WT background (MB751). White arrow heads point at co-localization at cross-walls in vegetative hyphae and the asterisk denotes a sporogenic hypha undergoing sporulation septation. Scale bar: 5 µm.

Researchers have identified a previously undescribed component that is important for the ability of bacteria to divide.

The findings by John Innes Centre researchers address the fundamental question as to how proliferate.

This work creates opportunities for further research into the cell biology of these organisms including studies aimed at better understanding the life cycle of harmful bacteria.

To grow and proliferate, bacteria (including the good and the bad) need to divide. Central to this process is a called FtsZ which assembles into a ring-like structure, called the Z-ring. For most bacteria, the Z-ring is essential to build the cell division machinery and for the synthesis of a dividing wall that allows the bacteria to physically separate.

Previously, there was little understanding of the mechanisms important for Z-ring assembly in a group of bacteria that include several medically and industrially relevant bacteria, such as the causative agent for Tuberculosis (TB), Mycobacterium tuberculosis, or the prolific antibiotic producers Streptomyces.

In a new study, researchers in the group of Dr. Susan Schlimpert identified a novel cell division protein, called SepH, in Streptomyces that directly regulates the assembly of Z-ring.

SepH is a highly conserved protein found not only in Streptomyces bacteria but also more distantly related bacteria, including several human pathogens such as M. tuberculosis and Corynebacterium diphtheriae.

Using a combination of in vivo studies, biochemical analyses and live-cell imaging, the team demonstrated that SepH has a similar function in cell division in two different model species: the filamentous-growing, antibiotic producer Streptomyces venezuelae and the single-cell, non-pathogenic cousin of M. tuberculosis, M. smegmatis.

“Having discovered a novel regulator that directly interacts with the cell division machinery, we now have the opportunity to further dissect this interaction with the aim of identifying strategies for inhibiting this interaction and thereby preventing cell division. This would be of particular interest with respect to the treatment of TB, an infection that still leads to the death of over one million people per year,” said Dr. Schlimpert.

Dr. Matt Bush, co-first author of the study said: “SepH was predicted to be a DNA-binding protein which implied that it regulates the production of other proteins. However, the protein domain that was predicted to mediate DNA-binding was in fact crucial for the interaction with the protein, FtsZ. That was unexpected and exciting, as there are not many other examples known in which the DNA-binding protein is actually mediating a protein-protein interaction.”

The next focus of research will be to gain a better mechanistic understanding of how SepH binds FtsZ and modulates FtsZ activity.

“A conserved protein directly regulates FtsZ dynamics in filamentous and unicellular actinobacteria” appeared in eLife.



More information:
Félix Ramos-León et al. A conserved cell division protein directly regulates FtsZ dynamics in filamentous and unicellular actinobacteria, eLife (2021). DOI: 10.7554/eLife.63387

Journal information:
eLife


Citation:
Research uncovers a critical factor in the assembly of cell division machinery in bacteria (2021, March 22)
retrieved 22 March 2021
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Hexbyte Glen Cove Five myths about the Big Bang thumbnail

Hexbyte Glen Cove Five myths about the Big Bang

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The Big Bang theory explains how the universe has evolved from an early state. Here is a beautiful view of a star cluster in the Milky Way. Credit: NASA, ESA, the Hubble Heritage Team (STScI / AURA), A. Nota (ESA / STScI), and the Westerlund 2 Science Team

The whole universe was packed together in an infinitely small point, then it exploded, and the entire mass that made up the universe was sent out into space.

An astrophysicist would tell you that everything about that statement is wrong.

“That’s not at all how we should think about the Big Bang,” says Torsten Bringmann.

Bringmann is a professor and works with cosmology and at the University of Oslo (UiO).

Are Raklev, a professor of theoretical physics at UiO, has noticed that a lot of descriptions give a misleading picture of what the Big Bang actually states.

Raklev and Bringmann take us through the most common misunderstandings.

Warm and dense

First of all, what does “Big Bang” really mean?

“The Big Bang theory is that about 14 billion years ago the universe was in a state that was much warmer and much denser, and that it expanded. That’s it, it’s not much more than that,” says Raklev.

Since then space has continued to expand and has become colder.

Based on the theory, scientists have gained a clearer overview of the history of the universe, such as when elementary particles were formed and when atoms, stars and galaxies formed.

They have a good idea of what happened back when the universe was about 10^-32 seconds old. That’s 0.0000000000000000000000000000000001 seconds, according to an article written by astrophysicist Jostein Riiser Kristiansen.

Now on to the myths.

An illustration of an explosion showing the substance of the mass shooting out in all directions is not an accurate picture of the Big Bang. Credit: Johan Swanepoel / Shutterstock / NTB scanpix

1. “It was an explosion.”

The Big Bang phrase itself makes it sound like it was an explosion, says Are Raklev. But that isn’t actually that accurate a description. You’ll find out why soon.

In the early 1920s, mathematician Alexander Friedmann discovered that Einstein’s general theory of relativity provides for an . The Belgian priest Georges Lemaître came to the same conclusion.

Shortly afterwards, Edwin Hubble showed that galaxies are actually moving apart.

The galaxies are moving away from us. The light from them is red-shifted, meaning the waves have become longer and shifted towards the red end of the light spectrum. Not only that, galaxies are disappearing from us faster and faster.

Someday, almost all the galaxies we can currently observe in telescopes will be out of view. Eventually the stars will go out and observers will look out into an eternally dark and lonely sky.

Fortunately, that’s an extremely long way off.

We can also play the story the opposite way. The galaxies are moving apart and they have been closer before.

“If you take the entire observable universe and rewind all the way back, everything fit into a very, very small area,” Raklev says.

Then we come to the point in time of the Big Bang. What happened?

It’s easy to think that the Big Bang was an explosion, in which substances were thrown out, like pieces of wood flying off after a hand grenade goes off.

“But when it comes to the Big Bang, it’s not the substance that travels out,” says Raklev.

“The universe itself expands, space itself expands.”

An explosion where the mass explodes in all directions is not an accurate picture of the Big Bang.

An illustration of the observable universe. Starting from the centre we see the solar system, the Kuiper belt, Orts cloud, the nearest solar systems and galaxies, then the cosmic web, the microwave background radiation and invisible plasma at the end. Credit: Pablo Carlos Budassi, wikimedia commons, CC BY-SA 3.0

2. “The universe is expanding into something.”

So it isn’t the galaxies that are moving apart, but space that’s expanding.

We can think of it as a ball of dough with raisins. The dough represents space and the raisins are the galaxies. Set the dough to rise, and the raisins will end up further apart, without actually having moved.

Bringmann uses the surface of a balloon as an example. Draw dots on the uninflated balloon and see how the distance between points increases as it inflates.

“At the same time, it’s true that galaxies also move due to mutual gravitational attraction—that’s an additional effect,” says Raklev.

A few galaxies are blue-shifting, meaning they’re moving towards us. This applies to some nearby galaxies. But over large distances, this effect is eclipsed by Hubble-Lemaître’s law, which states how fast galaxies are moving away in proportion to distance. In fact, the distance increases faster than light between points that are extremely far apart.

A ball of dough in the oven expands within the existing space inside the oven. What about the universe? What’s outside?

The universe doesn’t expand into anything. Scientists don’t believe that the universe has an edge.

That which we call the observable universe is a bubble surrounding us that is 93 billion light-years in diameter. The more distant something is that we look at, the farther back in time we’re seeing. We can’t observe or measure anything farther away than the distance light has managed to travel towards us since the Big Bang.

Since the universe has been expanding, the observable universe is counterintuitively larger than 14 billion light-years.

But scientists calculate that the universe outside our bubble is much, much larger than that, perhaps infinite.

The universe can be “flat,” it appears. That would mean that two light rays would remain parallel and never meet. If you tried to travel to the end of the universe, you would never reach it. The universe goes on infinitely.

If the universe has positive curvature, it could in theory be finite. But then it would be like a kind of strange sphere. If you traveled to the “end” you would end up in the same place you started, no matter which direction you took. It’s a bit like being able to travel around the world and ending up back where you started.

In either case, the universe can expand without having to expand into anything.

An infinite universe that’s getting bigger is still infinite. A “spherical universe” has no edge.

A galaxy cluster consisting of thousands of individual galaxies, 2.1 billion light-years from Earth. The universe we can see is unbelievably large and might even continue forever. Credit: NASA, ESA, and Johan Richard (Caltech, USA)

3. “The Big Bang had a center.”

If we imagine the Big Bang as an explosion, it’s easy to think that it exploded outwards, from a center. That’s how explosions work.

But that wasn’t the case with the Big Bang. Almost all are moving away from us, in all directions. It seems like the Earth was the center of the beginning of the universe. But it wasn’t.

All other observers would see the same thing from their home galaxy, Bringmann explains.

The universe is expanding everywhere at the same time. The Big Bang didn’t happen in any particular place.

“It happened everywhere,” says Raklev.

4. “The whole universe was gathered in a tiny little point.”

It’s true that our entire observable universe was gathered incredibly tightly together in very little space at the beginning of the Big Bang.

But how can the universe be infinite, and at the same time have been so small?

You might read that the universe was smaller than an atom at first and then the size of a football. But that analogy insinuates that space had boundaries in the beginning, and an edge.

“There’s nothing that says that the universe wasn’t already infinite at the Big Bang,” says Raklev.

“It was just smaller in the sense that what was then a meter, has now expanded into enormous distances of many billions of light years.”

When you talk about how big the universe was at certain times, it refers to our observable universe.

“The whole comes from a tiny little area that you can call a point. But the point next to it has also expanded, and the next point as well. It’s just that it’s so far away from us that we can’t observe it,” says Raklev.

Illustration of the Big Bang and the expansion and development of the universe. Credit: NASA / WMAP Science Team

5. “The universe was infinitely small, hot and dense.”

Maybe you’ve heard that the universe began as a singularity. Or that it was infinitely small, hot and so on. That might be true, but a lot of physicists don’t think it’s a correct understanding.

Singularities are an expression for mathematics that breaks down and can’t be described with ordinary physics, according to cosmologist Steen H. Hansen.

Bringmann sums up what this all means when it comes to the Big Bang.

“The universe today is a little bigger than it was yesterday. And it’s even a little bigger still than it was a million years ago. The Big Bang theory involves extrapolating this back in time. Then you need a theory for that: and that’s the general theory of relativity.”

“If I extrapolate all the way back, the universe gets smaller and smaller, it gets denser and denser, and warmer and warmer. Finally you get to a point where it’s really small, really hot and dense. That’s actually the Big Bang theory: that the universe started in such a condition. That’s where you really have to stop,” says Bringmann.

If you run the general relativity theory all the way back you reach a point of infinitely high density and heat, where the size is zero.

“That’s pure mathematical extrapolation beyond what the theory actually allows,” Bringmann says.

“You then come to a point where the energy density and temperatures are so high that we no longer have physical theories to describe them.”

He says that physicists need a different theory. And there are people who are researching just that.

“What do we need in order to describe such an extreme condition? That’s where we enter an area where you need a theory that combines gravity and quantum theory. No one has been able to formulate it yet. The expectation is precisely that a quantum gravity theory wouldn’t lead to the conclusion that everything goes back to one point,” Bringmann says.

So what happened at this time, the earliest point in the history of the , is still hidden from us, at least so far.



Citation:
Five myths about the Big Bang (2021, March 22)
retrieved 22 March 2021
from https://phys.org/news/2021-03-myths-big.html

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Hexbyte Glen Cove Multitalented mangroves: Spotlight on the trees that could save the planet thumbnail

Hexbyte Glen Cove Multitalented mangroves: Spotlight on the trees that could save the planet

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Credit: Alex Mustard

Picture the perfect tree. In your mind’s eye it is probably as majestic as a mighty oak, as tall as a towering redwood, bursting with fragrant, brightly coloured blossom and weighed down with succulent fruit. Mangroves are none of these things, but in their own inimitable way they are so much more.

Their party piece is turning into fresh water, a natural talent that enables them to thrive in the hostile hinterland between land and sea – an intertidal environment that most trees find too inhospitable. Many mangrove species are able to filter out as much as 90% of the salt found in seawater as it enters their roots. Some are able to excrete salt through glands in their leaves.

And that is just one of the numerous attributes that make mangroves so valuable – indispensable, in fact.

Many strings to their boughs

Their branches support myriad creatures, from praying mantids to primates. Their leaves are food for swamp specialists such as the proboscis monkey. And their elaborate root structures provide vital shelter for marine life, creating natural harbors for aquatic mammals such as manatees and dolphins, and nurseries for countless reef fish and crustaceans in their early stages of development when they are most vulnerable to predation.

But their importance doesn’t end there. These trees form a crucial two-way natural barrier between land and sea. They slow soil erosion, and collect ocean-bound river sediment that would otherwise smother the life out of offshore coral reefs. When floods, storms and tidal waves strike, they are often all that stands between coastal communities and catastrophe, providing a structure that is far more beneficial and cost-effective than engineered solutions.

Male proboscis monkey feeding on mangrove leaves. Credit: Zafer Kizilkaya

As if that wasn’t enough, they also help prevent climate collapse. Mangroves sequester and store vast quantities of carbon – estimated by the UN to be over four billion tons, equivalent to the combined annual emissions of the US and China – and they do this up to ten times more efficiently than rainforests and other terrestrial treescapes.

Mangroves are a true nature-based solution, helping to address many of the interlinked challenges we face relating to biodiversity loss, and supporting sustainable livelihoods.

Blue in green

In light of the huge potential of mangroves to store carbon and the need for to diversify away from tourism-based revenue streams, these trees are set to play a pivotal role in so-called blue carbon projects, which focus on the capture and storage of carbon in coastal and ocean ecosystems, such as mangroves, seagrasses and tidal salt marshes.

Blue carbon is set to become an important part of the global climate response, with governments and organizations supporting nature-based carbon projects that reduce emissions. Safeguarding existing mangroves and improving the management of these forests, while restoring those that have already been ripped out or degraded, not only prevents the release of further emissions but also increases the rate of removal of carbon dioxide from the atmosphere. This combined approach could help pave the way to achieving global climate goals, while providing all the co-benefits to nature and people that we know mangroves offer.

Aerial view of extensive mangrove forest, Borneo. Credit: Zafer Kizilkaya

And yet, despite their incalculable importance, have been subjected to more destruction and degradation during the past 50 years than any other type of forest on the planet.

Forests on the front line

The level of loss is staggering. According to the Food and Agriculture Organization of the United Nations, more than 20% of the world’s mangroves have been cleared since 1980 alone. Over a third of the world’s mangroves have already disappeared and in many countries less than half the original mangrove forest cover remains.

Mangroves are being ripped out at such an eye-watering rate largely to make way for a range of commercial enterprises including large-scale agriculture, shrimp farms, harbor construction, tourist development and other forms of human settlement. They are also suffering from unsustainable harvesting of their wood both for subsistence use and for financial profit.

Regrettably, their disproportionately large contribution to climate regulation also means that their disappearance has a correspondingly huge climate impact; emissions from destruction account for up to 10% of emissions from global deforestation even though the worldwide coverage of these trees extends to only 0.7% of the land surface.

Snapper hiding among mangrove roots, Belize. Credit: Zafer Kizilkaya

Root and branch reform

When these forests disappear, all the life-giving, life-saving services they provide disappear with them. That’s a loss our planet cannot afford. The protection and restoration of mangroves is critical to the fight against climate change, to the livelihoods and food security of coastal communities and to the health of terrestrial and marine ecosystems.

Today is the International Day of Forests. What better time to highlight the plight of arguably the most neglected and undervalued forest type of all? Too often, mangroves are viewed solely as resources to be exploited or cleared for short-term gain. Fauna & Flora International (FFI) recognizes their vital importance for the future of our planet, and we are working closely with communities, governments and businesses across our project portfolio to ensure that others see them through our eyes and begin to view mangroves as crucial coastal allies in our collective crusade against climate chaos.



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Multitalented mangroves: Spotlight on the trees that could save the planet (2021, March 22)
retrieved 22 March 2021
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Hexbyte Glen Cove Meteor streaks over Cuba, causes explosion thumbnail

Hexbyte Glen Cove Meteor streaks over Cuba, causes explosion

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Credit: CC0 Public Domain

What is believed to be a meteor lit the sky over eastern Cuba and caused an explosion, scientists on the island said Saturday. There were no reports of damage or injury.

The head of the National Seismological Service, Enrique Arango Arias, told the official Cubadebate news site that the phenomenon was noticed in the towns of Moa, Sagua de Tanamo and Maisí .

He said the service’s instruments “registered the expansive wave” of the .

Social media users reported seeing red and followed by an explosion at about 10:06 p.m. local time Friday.



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Meteor streaks over Cuba, causes explosion (2021, March 20)
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Hexbyte Glen Cove An easy way to reduce socioeconomic disparities thumbnail

Hexbyte Glen Cove An easy way to reduce socioeconomic disparities

Hexbyte Glen Cove

Researchers from Columbia University and Temple University published a new paper in the Journal of Marketing that examines how choice architecture can reduce socioeconomic disparities.

The study, forthcoming in the Journal of Marketing, is titled “Do Nudges Reduce Disparities? Choice Architecture Compensates for Low Consumer Knowledge” and is authored by Kellen Mrkva, Nathaniel Posner, Crystal Reeck, and Eric Johnson.

As Mrkva explains, “Our research demonstrates that people with (SES), low numerical ability, and low knowledge are most impacted by nudges. As a result, ‘good nudges,’ designed to encourage selection of options that are in people’s best interests, reduce SES disparities, helping low-SES people more than high-SES people.” On the other hand, nudges that encourage selection of inferior options exacerbate disparities relative to “good nudges” because low-SES consumers are more likely to retain inferior default options. In other words, nudges are a double-edged sword that can either reduce disparities or make matters worse because they impact low-SES people most. The research team generalized its findings across three different types of nudges, several different consumer contexts, and real retirement decisions.

This research has major implications, including for the COVID vaccination process. Across the country, millions of people are now eligible to get a COVID vaccine. However, the signup process is often unnecessarily complex. New York’s nycHealthy sign-up portal, for example, includes as many as 51 questions and requests that you upload your insurance card. As a result, many people, especially the elderly, poor, and less digitally literate, have struggled or failed to make an appointment. As Johnson explains, “Our research suggests that making beneficial behaviors like vaccination simpler has a crucial and underappreciated advantage—it reduces socioeconomic disparities. On the other hand, when these behaviors are unnecessarily complex, it is typically low-SES consumers who are harmed the most.”

In five experiments as well as data from real retirement decisions, the researchers show that people who are lower in SES, domain knowledge, and numeracy are impacted more by a variety of nudges. As a result, “good nudges” that facilitate selection of welfare-enhancing options reduce disparities by helping low-SES, low-knowledge, and low-numeracy consumers most.

In Study 1, participants made five consumer financial decisions. For each decision, they were randomly assigned to a “no default,” “good default,” or “bad default” condition (the latter two pre-selected correct or incorrect options, respectively). After they made these five decisions, participants completed common measures of the three hypothesized moderators—financial literacy, numeracy, and socioeconomic status. As predicted, there was a large default effect. There were also interactions between the default condition and the three moderators; participants lower in these moderators were more impacted by defaults. These effects remained significant when adding survey engagement, comprehension, need for cognition, agreeableness, decision time, and their interactions with condition to the model as covariates.

Study 2 examines whether these effects generalized across three different types of nudges and three decision contexts. It replicated the SES and financial literacy effects of Study 1 across all nudges and contexts. Unlike Study 1 and all subsequent studies, the x numeracy interaction was not significant. The key effects remained significant when controlling for a measure of fluid intelligence.

Study 3 uses syndicated data from stratified random samples of American households about their retirement investment decisions to examine a sample of people who work for companies that use defaults to automatically enroll employees into retirement contributions. Respondents reported whether they retained or opted out of the default contribution amount and default investment allocation. Evidence supports that lower-SES and less financially literate people are more impacted by nudges and thus less likely to opt out of these retirement defaults: Lower-SES participants were less likely to opt out as were participants with lower financial literacy.

Study 4 replicated these effects in the context of COVID-19 health decisions (e.g., deciding whether to wear a mask). Additionally, domain-specific health knowledge moderated default effects whereas other-domain knowledge did not. Studies 5-6 replicated the predicted moderators from Study 1 with incentives. Mediation models suggest that people with lower SES, domain knowledge, and numeracy were more impacted by nudges partly because they experience higher uncertainty and decision anxiety when making decisions.

Across the six studies, nudges influenced choice disparities across people. Posner summarizes the study by saying “Our results suggest that nudges that make behaviors such as retail purchases, vaccine sign-up, and retirement contributions more automatic can reduce socioeconomic inequities.”



More information:
Kellen

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Hexbyte Glen Cove Icelandic volcano subsiding after first eruption in 900 years thumbnail

Hexbyte Glen Cove Icelandic volcano subsiding after first eruption in 900 years

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Lava flowing from the erupting Fagradalsfjall volcano

A volcano that spewed glowing red lava near Iceland’s capital Reykjavik after awakening for the first time in 900 years appeared to be subsiding on Saturday, posing no danger to people, experts said.

Streams of red lava bubbled and flowed out of a fissure in a valley in Geldingadalur, close to Mount Fagradalsfjall on the Reykjanes peninsula in southwestern Iceland.

As the lava flow slowed under rain showers on Saturday, a blue gas plume and a vapour cloud rose from the site, just 40 kilometres (25 miles) from the capital and near a popular tourist destination, the Blue Lagoon geothermal spa.

The eruption occurred on Friday around 2045 GMT, lighting up the night sky with a crimson glow as hundreds of small earthquakes shook the area.

While Iceland’s Keflavik International Airport and the small fishing port of Grindavik are just a few kilometres away, the zone is uninhabited and the eruption did not present any danger to the public.

“The eruption is considered small at this stage and the volcanic activity has somewhat decreased since yesterday evening,” the Icelandic Meteorological Office (IMO), which monitors seismic activity, said in a statement on Saturday.

It said the “eruptive fissure” measured approximately 500 to 700 metres (1,640 to 2,300 feet).

The red shimmer from magma flowing out of a fissure in a valley in Geldingadalur

The lava area, it added, was less than one square kilometre (0.4 square mile), with small lava fountains.

Speaking to reporters, University of Iceland geophysicist Magnus Tumi Gudmundsson described the valley as an “ideal” spot for the eruption, likening it to “a bathtub the lava can slowly leak into.”

IMO earthquake hazards coordinator Kristin Jonsdottir meanwhile said it was “very likely the eruption will last for the next few days”.

Friday’s eruption took place in the Krysuvik volcanic system, which does not have a central volcano, about five kilometres inland from the southern coast.

Sigurdur Kristmundsson, a 54-year-old Grindavik port official, told AFP that locals were exhilarated by the eruption.

“Nobody is in danger or anything like that. So I think people are excited and not afraid of it.”

Dramatic images showed streams of red lava bubbling up from the ground

Dormant for 900 years

Access to the area was initially blocked off but later opened to the public, though Iceland’s Department of Civil Protection and Emergency Management stressed the several-hour hike from the nearest road was only recommended for those “used to being outdoors in difficult conditions.”

Gases from a volcanic eruption—especially sulphur dioxide—can be elevated in the immediate vicinity, and may pose a danger to health and even be fatal.

Gas pollution can also be carried by the wind.

“Currently gas pollution is not expected to cause much discomfort for people except close up to the source of the eruption. The gas emissions will be monitored closely,” the IMO said.

The Krysuvik system has been inactive for the past 900 years, according to the IMO, while the last eruption on the Reykjanes peninsula dates back almost 800 years and lasted about 30 years, from 1210 to 1240.

Iceland volcano erupts

But the region had been under increased surveillance for several weeks after a 5.7-magnitude earthquake was registered on February 24 near Mount Keilir on the outskirts of Reykjavik.

Since then more than 50,000 smaller tremors had been registered, and magma was detected just one kilometre under the Earth’s surface in recent days near Fagradalsfjall.

Geophysicist Gudmundsson said the eruption signalled a new period “which may last centuries with eruptions, possibly 10 years to 100 years apart.”

Land of fire and ice

Iceland has 32 volcanic systems currently considered active, the highest number in Europe. The country has had an eruption every five years on average.

The vast island near the Arctic Circle straddles the Mid-Atlantic Ridge, a crack on the ocean floor separating the Eurasian and North American tectonic plates.

Iceland has 32 volcanic systems currently considered active, the highest number in Europe

The shifting of these plates is in part responsible for Iceland’s intense volcanic activity.

The most recent eruption was at Holuhraun, beginning in August 2014 and ending in February 2015, in the Bardarbunga volcanic system in an uninhabited area in the centre of the island.

That eruption did not cause any major disruptions outside the immediate vicinity.

But in 2010, an eruption at the Eyjafjallajokull volcano sent huge clouds of smoke and ash into the atmosphere, disrupting air traffic for more than a week and cancelling more than 100,000 flights worldwide, which left some 10 million passengers stranded.



© 2021 AFP

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Icelandic volcano subsiding after first eruption in 900 years (2021, March 20)
retrieved 21 March 2021
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Hexbyte Glen Cove New study shows microplastics turn into 'hubs' for pathogens, antibiotic-resistant bacteria thumbnail

Hexbyte Glen Cove New study shows microplastics turn into ‘hubs’ for pathogens, antibiotic-resistant bacteria

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A single use of a facial exfoliator can release 5,000 -100,000 microplastics to the environment. Credit: NJIT

It’s estimated that an average-sized wastewater treatment plant serving roughly 400,000 residents will discharge up to 2,000,000 microplastic particles into the environment each day. Yet, researchers are still learning the environmental and human health impact of these ultra-fine plastic particles, less than 5 millimeters in length, found in everything from cosmetics, toothpaste and clothing microfibers, to our food, air and drinking water.

Now, researchers at New Jersey Institute of Technology have shown that ubiquitous microplastics can become ‘hubs’ for and pathogens to grow once they wash down household drains and enter treatment plants—forming a slimy layer of buildup, or biofilm, on their surface that allows pathogenic microorganisms and antibiotic waste to attach and comingle.

In findings published in the Journal of Hazardous Materials Letters, researchers found certain strains of elevated by up to 30 times while living on biofilms that can form inside activated sludge units at municipal wastewater treatment plants.

“A number of recent studies have focused on the negative impacts that millions of tons of microplastic waste a year is having on our freshwater and ocean environments, but until now the role of microplastics in our towns’ and cities’ wastewater treatment processes has largely been unknown,” said Mengyan Li, associate professor of chemistry and environmental science at NJIT and the study’s corresponding author. “These wastewater treatment plants can be hotspots where various chemicals, antibiotic-resistant bacteria and pathogens converge and what our study shows is that microplastics can serve as their carriers, posing imminent risks to aquatic biota and human health if they bypass the water treatment process.”

“Most wastewater treatment plants are not designed for the removal of microplastics, so they are constantly being released into the receiving environment,” added Dung Ngoc Pham, NJIT Ph.D. candidate and first author of the study. “Our goal was to investigate whether or not microplastics are enriching antibiotic-resistant bacteria from activated sludge at municipal wastewater treatment plants, and if so, learn more about the microbial communities involved.”

In their study, the team collected batches of sludge samples from three domestic in northern New Jersey, inoculating the samples in the lab with two widespread commercial microplastics—polyethylene (PE) and polystyrene (PS). The team used a combination of quantitative PCR and next-generation sequencing techniques to identify the species of bacteria that tend to grow on the microplastics, tracking genetic changes of the bacteria along the way.

The analysis revealed that three genes in particular—sul1, sul2 and intI1— known to aid resistance to common antibiotics, sulfonamides, were found to be up to 30 times greater on the microplastic biofilms than in the lab’s control tests using sand biofilms after just three days.

Microscopy images showing biofilms attached on polyethylene microplastics. The white arrows point to the biofilms. The scale bars represent 10 μm in length. Credit: NJIT

When the team spiked the samples with the antibiotic, sulfamethoxazole (SMX), they found it further amplified the antibiotic resistance genes by up to 4.5-fold.

“Previously, we thought the presence of antibiotics would be necessary to enhance antibiotic-resistance genes in these microplastic-associated bacteria, but it seems microplastics can naturally allow for uptake of these resistance genes on their own.” said Pham. “The presence of antibiotics does have a significant multiplier effect however.”

Eight different species of bacteria were found highly enriched on the microplastics. Among these species, the team observed two emerging human pathogens typically linked with respiratory infection, Raoultella ornithinolytica and Stenotrophomonas maltophilia, frequently hitchhiking on the microplastic biofilms.

The team say the most common strain found on the microplastics by far, Novosphingobium pokkalii, is likely a key initiator in forming the sticky biofilm that attracts such pathogens—as it proliferates it may contribute to the deterioration of the plastic and expand the biofilm. At the same time, the team’s study highlighted the role of the gene, intI1, a mobile genetic element chiefly responsible for enabling the exchange of antibiotic resistance genes among the microplastic-bound microbes.

“We might think of microplastics as tiny beads, but they provide an enormous surface area for microbes to reside,” explained Li. “When these microplastics enter the wastewater treatment plant and mix in with sludge, bacteria like Novosphingobium can accidentally attach to the surface and secrete glue-like extracellular substances. As other bacteria attach to the surface and grow, they can even swap DNA with each other. This is how the are being spread among the community.”

“We have evidence that the bacteria developed resistance to other this way as well, such as aminoglycoside, beta-lactam and trimethoprim,” added Pham.

Now, Li says the lab is further studying the role of Novosphingobium in formation on microplastics. The team is also seeking to better understand the extent to which such pathogen-carrying microplastics may be bypassing water treatment processes, by studying resistance of microplastic biofilms during wastewater treatment with disinfectants such as UV light and chlorine.

“Some states are already considering new regulations on the use of microplastics in consumer products. This study raises calls for further investigation on microplastic biofilms in our wastewater systems and development of effective means for removing microplastics in aquatic environments,” said Li.



More information:
Dung Ngoc Pham et al, Microplastics as hubs enriching antibiotic-resistant bacteria and pathogens in municipal activated sludge, Journal of Hazardous Materials Letters (2021). DOI: 10.1016/j.hazl.2021.100014

Citation:
New study shows microplastics turn into ‘hubs’ for pathogens, antibiotic-resistant bacteria (2021, March 19)
retrieved 20 March 2021
from https://phys.org/news/2021-03-microplastics-hubs-pathogens-antibiotic-resistant-bacteria.html

This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no

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Hexbyte Glen Cove Chemists use supercomputers to understand solvents thumbnail

Hexbyte Glen Cove Chemists use supercomputers to understand solvents

Hexbyte Glen Cove

UC student Andrew Eisenhart used quantum simulations to understand a common solvent that holds promise for green energy. Credit: Colleen Kelley/UC Creative

To understand the fundamental properties of an industrial solvent, chemists with the University of Cincinnati turned to a supercomputer.

UC chemistry professor and department head Thomas Beck and UC graduate student Andrew Eisenhart ran to understand glycerol carbonate, a compound used in biodiesel and as a common solvent.

They found that the provided detail about hydrogen bonding in determining the structural and dynamic properties of the liquid that was missing from classical models. The study was published in the Journal of Physical Chemistry B.

Glycerol carbonate could be a more environmentally friendly chemical solvent for things like batteries. But chemists have to know more about what’s going on in these solutions. They studied the compounds potassium fluoride and .

“The study we did gives us a fundamental understanding of how small changes to a can have larger consequences for the solvent as a whole,” Eisenhart said. “And how these small changes make its interactions with very important things like ions and can have an effect on things like battery performance.”

Water is a seemingly simple solvent, as anyone who has stirred sugar in their coffee can attest.

UC student Andrew Eisenhart, left, and UC chemistry department head Thomas Beck collaborated on a research study of glycerol carbonate. Credit: Colleen Kelley/UC Creative

“People have studied for hundreds of years—Galileo studied the origin of flotation in water. Even with all that research, we don’t have a complete understanding of the interactions in water,” Beck said. “It’s amazing because it’s a simple molecule but the behavior is complex.”

For the quantum simulation, the chemists turned to UC’s Advanced Research Computing Center and the Ohio Supercomputer Center. Quantum simulations provide a tool to help chemists better understand interactions on an atomic scale.

“Quantum simulations have been around for quite a while,” Eisenhart said. “But the hardware that’s been evolving recently—things like graphics processing units and their acceleration when applied to these problems—creates the ability to study larger systems than we could in the past.”

“How do ions dissolve in this liquid compared to water? First we had to understand what the basic structure was of the liquid,” Beck said.

The research was funded by a grant from the National Science Foundation.

Every lithium ion battery contains a solvent. Finding a better one could improve and efficiency.

“The world is moving in a sustainability direction. It’s pretty clear that wind and solar will be two major contributors along with other green energy,” Beck said. “But the energy generated is intermittent. So you need methods for large-scale energy storage so that if it’s cloudy for two days, a city can stay running.”



More information:
Andrew E. Eisenhart et al, Quantum Simulations of Hydrogen Bonding Effects in Glycerol Carbonate Electrolyte Solutions, The Journal of Physical Chemistry B (2021). DOI: 10.1021/acs.jpcb.0c10942

Citation:
Chemists use supercomputers to understand solvents (2021, March 19)
retrieved 20 March 2021
from https://phys.org/news/2021-03-chemists-supercomputers-solvents.html

This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no
part may be reproduced without the written permission. The content is provided for information purposes only.

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