Scientist mimic nature to make nano particle metallic snowflakes

Scientists in New Zealand and Australia working at the level of atoms created something unexpected: tiny metallic snowflakes.

Peer-Reviewed Publication

UNIVERSITY OF AUCKLAND

 

IMAGE: NANO-SCALE SNOWFLAKE FROM GALLIUM SOLVENT view more 

CREDIT: IMAGE: WAIPAPA TAUMATA RAU, UNIVERSITY OF AUCKLAND

Scientists in New Zealand and Australia working at the level of atoms created something unexpected: tiny metallic snowflakes.
Why’s that significant? Because coaxing individual atoms to cooperate in desired ways is leading to a revolution in engineering and technology via nanomaterials (And creating snowflakes is cool.)
 Nanoscale structures (a nanometre is one billionth of a metre) can aid electronic manufacturing, make materials stronger yet lighter, or aid environmental clean-ups by binding to toxins.

To create metallic nanocrystals, New Zealand and Australian scientists have been experimenting with gallium, a soft, silvery metal which is used in semiconductors and, unusually, liquifies at just above room temperature. Their results were just reported in the journal Science.

Professor Nicola Gaston and research fellow Dr Steph Lambie, both of Waipapa Taumata Rau, University of Auckland, and Dr Krista Steenbergen of Te Herenga Waka, Victoria University of Wellington, collaborated with colleagues in Australia led by Professor Kourosh Kalantar-Zadeh at the University of New South Wales.

The Australian team worked in the lab with nickel, copper, zinc, tin, platinum, bismuth, silver and aluminium, growing metal crystals in a liquid solvent of gallium. Metals were dissolved in gallium at high temperatures. Once cooled, the metallic crystals emerged while the gallium remained liquid. The New Zealand team, part of the MacDiarmid Institute for Advanced Materials and Nanotechnology, a national Centre of Research Excellence, carried out simulations of molecular dynamics to explain why differently shaped crystals emerge from different metals. (The government’s Marsden Fund supported the research.)

“What we are learning is that the structure of the liquid gallium is very important,” says Gaston. “That’s novel because we usually think of liquids as lacking structure or being only randomly structured.” Interactions between the atomistic structures of the different metals and the liquid gallium cause differently shaped crystals to emerge, the scientists showed.

The crystals included cubes, rods, hexagonal plates and the zinc snowflake shapes. The six-branched symmetry of zinc, with each atom surrounded by six neighbours at equivalent distances, accounts for the snowflake design. “In contrast to top-down approaches to forming nanostructure – by cutting away material – this bottom-up approaches relies on atoms self-assembling,” says Gaston. “This is how nature makes nanoparticles, and is both less wasteful and much more precise than top-down methods.” She says the research has opened up a new, unexplored pathway for metallic nanostructures. “There’s also something very cool in creating a metallic snowflake!”

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JOURNAL

Science

DOI

10.1126/science.abm2731 

METHOD OF RESEARCH

Experimental study

SUBJECT OF RESEARCH

Not applicable

ARTICLE TITLE

Liquid metal synthesis solvents for metallic crystals

ARTICLE PUBLICATION DATE

8-Dec-2022

Prudent healthcare approach key to transforming health and care system

Peer-Reviewed Publication

SAGE

A prudent approach to health and care, incorporating the values people, patients and local communities attribute to their health and care services, is key to transforming the health and care system.

Leaders from Welsh health and care think tank the Bevan Commission, writing in the Journal of the Royal Society of Medicine, say that the range of effects regarded as valuable by patients should be taken into account. They also say that prudent planning and decision-making should include stopping low-value work, using all skills and resources to best effect, and redirecting resources to those in greatest need.

Helen Howson, Director of the Bevan Commission, said: “The COVID-19 pandemic highlighted the importance of marrying our values with value to focus on what really matters. A prudent approach to health and care aims to work co-productively with people, managing all the skills and resources we have available to us in a way that helps us to achieve the best possible outcomes for all.”

She went onto say that the health and social care system must ensure that it puts people’s needs first and not those of the system or its services.

Future investment decisions must recognise the prudence of protecting and improving health and wellbeing and population health which should be based on a values-based leadership model, write the authors. Leaders, they say, should be flexible and open to challenge and change at every level and face up to questions about how the workforce will operate and be trained in the future.

Ms Howson added: “There is a need to transform our system through our values while remaining aligned to the founding principles of the National Health Service. By incorporating the prudent principles and vision, the system in Wales will understand and tackle health inequalities as part of a whole-system, values-based approach.”

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JOURNAL

Journal of the Royal Society of Medicine

DOI

10.1177/01410768221142026 

ARTICLE TITLE

‘Values to value’ for recovery and renewal: prudent healthcare the key to transforming the health and care system

ARTICLE PUBLICATION DATE

9-Dec-2022

Longitudinal field laser processing enabling high aspect ratio 10 nm features produced in sapphire

Peer-Reviewed Publication

LIGHT PUBLISHING CENTER, CHANGCHUN INSTITUTE OF OPTICS, FINE MECHANICS AND PHYSICS, CAS

 

IMAGE: A, THE COLLIMATED GAUSSIAN SHAPED INTO HIGH QUALITY THIN ANNULAR BEAM. B, THE PRINCIPLE OF THE LONGITUDINAL FIELD GENERATION AND THE COMPARISON OF THE CONVENTIONAL FIELD AND THE LONGITUDINAL FIELD FOR MATERIALS ABLATION. C, 10 NM FEATURE GENERATED ON SAPPHIRE AND THE CROSS SECTION OF THE CROSS SECTION OF A HOLE WITH NO TAPER AND DEPTH TO WIDTH ASPECT RATIO OVER 16. view more 

CREDIT: BY ZHAOQING LI, OLIVIER ALLEGRE, LIN LI

Towards the end of the 19th century, Abbe and Rayleigh formulated the principles of optical diffraction that limits the resolution of optical instruments in the far-field where the distance between the target and the optical element is far greater than the optical wavelength. These principles remained unchallenged for over a century until new developments in optical technologies opened up new avenues for breaking the diffraction limit. One such technique uses focused annular amplitude collimated laser beams with a radial polarisation, so that opposite direction plane waves propagate towards the same focal point and cause constructive interference in the optical axis, leading to a symmetrical focal spot where all-the electric fields are oriented in the longitudinal direction, parallel to the optical axis. Although a number of prior investigations attempted to demonstrate the possibility to break the optical diffraction limit by using the so-called longitudinal field, the purity of these fields has never been sufficiently high to achieve the best processing resolutions. On the one hand, the spherical aberration of a high NA lens focusing is difficult to overcome by using standard optical lenses. On the other, a high-quality annular collimated beam with a very small width and a uniform distribution is required, which is also difficult to realise by only blocking the central area of the beam. If the focused laser beam is a mixture of longitudinal and transverse fields, the processing resolution is reduced.

In a new paper published in Light: Science & Applications, a team of scientists led by Professor Lin Li and Dr Olivier Allegre from the Laser Processing Research Centre, The University of Manchester, UK, has developed a novel method to experimentally demonstrate a longitudinal femtosecond laser field (i.e., parallel to the optical axis) with an unprecedented high purity (94.7%) and its interactions with polished silicon, copper, and sapphire. A new optical setup is developed using an 800 nm wavelength femtosecond laser source and a pair of spatial light modulators (SLMs) in a double 4-f optical arrangement to tailor the laser light fields and realise high-quality and uniform beam shaping to correct the spherical aberration of the 0.95 NA objective lens. The experiments involved focusing the beam first using an aplanatic 0.75 NA lens to confirm the presence of the longitudinal fields, and then using a 0.95 NA lens to further understand the characteristics of the focused longitudinal fields and their effects on laser materials processing. A number of polarisation states, beam intensity distribution and wavefront ablation profiles were investigated and the results were compared with theoretical models of the longitudinal field. Material processing with a resolution (10 nm, i.e., l/80) well beyond the far-field diffraction limit at the infrared laser wavelength of 800 nm was demonstrated on polished sapphire in air.

Dr. Zhaoqing Li summarized the operational principle of his PhD project：

“To generate high purity longitudinal field, the laser beam needs to be shaped into a high quality annular beam. We firstly shaped the original collimated Gaussian into a perfect Gaussian beam, and then converted it to a thin annular beam, by using a spatial light modulator (SLM)”

“Before focusing the annular laser beam with radial polarisation with a 0.95 NA objective lens, the spherical aberration needs to be precisely corrected, to make sure the laser beam is focused into a same plane. We realised it by using another spatial light modulator (SLM), so we could achieve the high-quality longitudinal field, with a purity of up to 94.7%”.

“By focusing the longitudinal field on sapphire, holes with a diameter as small as 10 nm could be created, which is much smaller than the previously published results based on strong nonlinear laser materials interaction processes.”

“To verify the cross-section characteristics of these tiny holes, focused ion beam (FIB) cross-sectioning was conducted. For a 30 nm diameter hole, the depth was over 500 nm with a zero taper.”

Dr. Olivier Allegre summarized the principle of the longitudinal ablation:

“The extremely small feature size and very high depth to width aspect ratio with parallel hole walls observed in this study could indicate that the material removal mechanism induced with the longitudinal field is fundamentally different from those induced with a transverse linear polarisation. This phenomenon is rarely seen in laser materials processing at this scale with a single pulse. ”

“In the experimental results demonstrated in this paper, the electrical field is to the laser beam axis. The laser beam with the longitudinal field could behave somewhat like a particle accelerator and enable the electron (with negative charge) and ion (positive charge) to be ejected more effectively than in a standard Coulombic explosion. The very deep holes produced in our experiments show the possibility of electron acceleration and charge polarisation in the holes for material removal.”

Professor Lin Li commented: “The significance of this research is the demonstration of super-resolution materials processing with an infrared laser beam, which breaks the optical diffraction limit in the far field, while most previous approaches are either based on costly extreme ultraviolet (EUV) laser wavelengths that operate within the optical diffraction limit, or on the use of near field optics that make the working distance too close to be practically useful. The very high aspect ratio of the laser processed features points out a new material removal mechanism.”

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JOURNAL

Light Science & Applications

DOI

10.1038/s41377-022-00962-x 

ARTICLE PUBLICATION DATE

2-Dec-2022

EVERYBODY DOWN, NOBODY GETS HURT

Masks can put cognitive performance in check

Wearing a face mask can temporarily disrupt decision-making in some situations according to University of Queensland research

Peer-Reviewed Publication

UNIVERSITY OF QUEENSLAND

Wearing a face mask can temporarily disrupt decision-making in some situations according to University of Queensland research.

Dr David Smerdon from UQ’s School of Economics analysed almost three million chess moves played by more than eight thousand people in 18 countries before and during the COVID-19 pandemic and found wearing a mask substantially reduced the average quality of player decisions.

“The decrease in performance was due to the annoyance caused by the masks rather than a physiological mechanism, but people adapted to the distraction over time,” Dr Smerdon said.

“The data showed masks were more likely to decrease performance in situations where there was a demanding mental task with a high working memory load.

“This is something to keep in mind for occupations in the STEM fields of science, technology, engineering and mathematics as well as other professions that demand a high level of working memory such as language interpreters, performers, waiters and teachers.”

Dr Smerdon, an Australian chess Grandmaster, said while mask mandates had helped to curb the spread of COVID-19, almost nothing was known about their impact on cognitive performance.

“At the moment there are no large studies on the impact of mask wearing on the general population,” he said.

“Chess can provide us with that insight as it requires calculation, memory, problem-solving and pattern recognition and has been used extensively in psychology, neuroscience and economics to measure changes in cognitive performance.”

Dr Smerdon’s study found that while mask wearing had a negative impact on chess performance, the effect subsided after four to six hours of playing.

“The results suggest that the effect of masks may depend on the type of task, the duration of the task and working memory load,” he said.

Dr Smerdon said understanding the impact of mask wearing on decision-making could help individuals and organisations better evaluate when and how to use them.

“For example, education policy makers may need to bear in mind the disruptive effects of masks when designing exam conditions to address concerns about student health and fairness,” he said.

The study has been published in PNAS.

Media: Dr David Smerdon, d.smerdon@uq.edu.au, +61 7 334 67047, +61 (0)490 874 970; Caroline Enright, communications@bel.uq.edu.au or +61 (0)430 007 435.

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JOURNAL

Proceedings of the National Academy of Sciences

SUBJECT OF RESEARCH

People

ARTICLE TITLE

The effect of masks on cognitive performance

PAN-based activated carbon fibers for efficient adsorption of nitrate ion contaminants

Scientists now develop sodium carbonate-activated polyacrylonitrile-based carbon fibers for nitrate ion removal from natural groundwater sources

Peer-Reviewed Publication

CHIBA UNIVERSITY

 

IMAGE: RESEARCHERS AT CHIBA UNIVERSITY, JAPAN, PREPARED POLYACRYLONITRILE (PAN)-BASED ACTIVATED CARBON FIBERS THAT ARE CAPABLE OF REMOVING NITRATE IONS FROM THE ENVIRONMENT. A. ADSORBENT STRUCTURE AND ITS SURFACE FUNCTIONAL GROUPS. QUATERNARY NITROGEN (N-Q), INCLUDING GRAPHITIC NITROGEN, AND ALIPHATIC AMINE COULD BE EFFECTIVE FOR THE REMOVAL OF ANIONIC POLLUTANTS, SUCH AS NITRATE, PHOSPHATE, CHROMIUM, AND ARSENIC ANIONS. B. A GRAPH REPRESENTING THE INFLUENCE OF EQUILIBRIUM SOLUTION PH (PHE) ON THE AMOUNT OF NO3- ADSORPTION. view more 

CREDIT: MOTOI MACHIDA FROM CHIBA UNIVERSITY, JAPAN

Nitrate ion is a common pollutant produced by municipal waste treatment systems, agricultural run-offs, and livestock waste. Although an essential component of fertilizers and   necessary for growing food, nitrates can be harmful when left to circulate in our ecosystem without proper treatment. It can, for instance, lead to algal bloom in water bodies, which reduces the amount of dissolved oxygen in water, posing a threat to aquatic organisms. Nitrate ions have also been associated with blood disorders in infants and digestive cancers in adults. Hence, an easy and cost-effective way to remove nitrate ions from our ecosystem is crucial.

Over the years, researchers have tried and tested several materials that can remove nitrate ions via adsorption. A popular approach is to use adsorbent materials, such as activated carbon fibers (ACF). The porous structure of ACFs enables the introduction of a wide range of functional groups that can be chosen per the adsorption requirements. They are also easy to recover and reuse. Unfortunately, there are certain shortcomings of ACF that hinder its applications.

Prof. Motoi Machida from Chiba University, Japan, who leads the research on nitrate ion removal, sheds some light on the issues faced. “Carbonaceous materials like activated carbons are usually functionalized with negatively charged functional groups, such as carboxy, carbonyl or phenol, which show excellent adsorption performance for positively charged ions and organic pollutants but are ineffective against inorganic negatively charged ions,” he explains. “So, we wanted to develop a durable ACF-based material that can efficiently adsorb nitrate ions and retain adsorption capacity for multiple uses.”

In a recent breakthrough made available online on 10 October 2022 and published in SN Applied Sciences on 22 October 2022, Prof. Machida, along with Ms. Natsuho Sato and Associate Prof. Yoshimasa Amano from Chiba University, designed sodium carbonate activated, polyacrylonitrile (PAN)-based ACF with high nitrogen content for nitrate ion removal. To increase the adsorption property of the PAN-ACF, the team activated them with sodium carbonate at 800°C. They further heat-treated the fibers at 950°C, which reduced the nitrogen content but increased the amount of quaternary nitrogen (N-Q), a positively charged functional group capable of nitrate adsorption.

Following the preparation process, the team carried out tests to analyze the nitrate ion adsorption dynamics of the material. The results showed that heat treatment increased the nitrate adsorption capacity by eliminating nitrate-repelling functional groups, such as –COOH and –COO–. The PAN-ACF material showed excellent adsorption properties, with an adsorption capacity of 0.5 mmol/g nitrate ions from water.

The team also conducted long-term degradation studies under different storage conditions to figure out the best way of storing the material for optimum reuse results. They found that keeping the ACFs in hydrochloric acid solution or under vacuum kept them stable. The adsorption capacity and degradation studies revealed that the material showed a consistent adsorption rate at a pH of 4-5, an encouraging find since 4-5 is the pH range of groundwater.

“Our new robust material can withstand treatments with boiling water, and strong acidic and basic solutions, thereby still easily regenerate with minimal loss in adsorption capacity,” adds Prof. Machida.

Overall, the new PAN-ACF presented in the study can not only treat environmental water by removing harmful nitrate ions but also help reduce the dependence on conventional plastic material-based ion exchange resins by replacing them with more environment-friendly active carbon-based ion removers.

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JOURNAL

SN Applied Sciences

DOI

10.1007/s42452-022-05191-w 

METHOD OF RESEARCH

Experimental study

SUBJECT OF RESEARCH

Not applicable

ARTICLE TITLE

Adsorption characteristics of nitrate ion by sodium carbonate activated PAN‑based activated carbon fiber

Short CBT program is also effective at reducing anxiety among school children

Researchers developed 20-minute-long (14 sessions) cognitive behavioral interventions to prevent anxiety problems in school-going children in Japan

Peer-Reviewed Publication

CHIBA UNIVERSITY

 

IMAGE: A STUDY CONDUCTED IN JAPAN INDICATED THAT CHILDREN WHO UNDERWENT 20-MINUTE -LONG COGNITIVE BEHAVIOURAL THERAPY-BASED PROGRAMS EXHIBITED LOWER SYMPTOMS OF ANXIETY AS COMPARED TO CHILDREN WHO DID NOT view more 

CREDIT: YUKO URAO FROM CHIBA UNIVERSITY

Anxiety disorders are highly prevalent psychological disorders among children. Anxiety negatively affects a child’s sense of self-esteem, leading to under-achievement in school. Moreover, anxiety may exacerbate low self-esteem in children who already experience it. This increases their likelihood of avoiding socialization, indulging in negative interactions with their peers, and remaining absent from classes. If left untreated, anxiety can lead to severe psychological disorders over time. To remedy this, a preventive intervention based on Cognitive Behavioral Therapy (CBT) for children— ‘Journey of the Brave’— was developed and introduced in Japanese schools in 2014.

 

While the program was somewhat effective, each CBT session took 45 minutes to complete over a span of 10 weeks, during which the regular class time was lost. In Japan, school going children have busy schedules due to a packed school curriculum, and it is quite difficult to set time aside for a preventive program.

 

Recently a team of researchers led by Dr. Yuko Urao—a Specially Appointed Lecturer at the Research Centre for Child Mental Development, including Dr. Eiji Shimizu and Ms. Michiko Yoshida from the Graduate School of Medicine, Chiba University, and Dr. Yasunori Sato from Keio University School of Medicine, Japan developed a streamlined and shorter version of the Journey of the Brave CBT-program. Their findings were published online on October 25, 2022, in Volume 22 of BMC Psychiatry.

 

“The effectiveness of the CBT-based anxiety prevention program “Journey of the Brave”, aimed at Japanese higher-grade elementary school children has been confirmed by previous studies. But to implement and spread it on a large scale was problematic due to difficulties in securing extensive class time of ten 45-minute-long sessions,” said Dr. Urao while discussing the motivation behind the study.

 

The team spent 14 weeks and designed the sessions to only last for 20 minutes. They conducted them during the homeroom activity time in the morning instead of after school hours, for children aged 10–11 of a Japanese school. This age group was targeted since children of these ages experience class shuffle and tend to take on new responsibilities as school or class leaders.

Further, the children were divided into control and intervention groups, with the former not attending any CBT-based sessions. The team assessed the children at the pre-intervention and post-intervention stages, as well as during a 2-month follow-up period. Their anxiety-based symptoms were measured using the Spence Children’s Anxiety Scale (SCAS), and the behavioral problems were measured using the Strengths and Difficulties Questionnaire (SDQ).

 

The findings suggested a statistically significant reduction in the SCAS scores during the 2-month follow-up period, as well as a reduction in the SDQ scores. These findings suggest that the children benefitted from the CBT-based program when it was delivered in a short and divided format.

 

“Since this version of the program is shorter, a greater number of schools will be able to implement it. In addition, the greater number of schools participate, the more teachers will be able to focus on children’s anxiety. Moreover, it will lead to an improved school environment where children will retain their peace of mind.” Dr. Urao said while discussing the findings.

 

Why is it important to prevent symptoms of anxiety of schoolchildren? Dr. Urao muses, “When CBT-based anxiety prevention programs prevail and help children learn self-control over their anxious feelings, their mental-health related problems will decrease, allowing them to grow to their full potential.”

 

CAPTION

Journey of the Brave is a behavioral intervention program that was developed with an aim to reduce anxiety among school-going children in Japan

CREDIT

Yuko Urao from Chiba University

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JOURNAL

BMC Psychiatry

DOI

10.1186/s12888-022-04326-y 

METHOD OF RESEARCH

Randomized controlled/clinical trial

SUBJECT OF RESEARCH

People

ARTICLE TITLE

School-based cognitive behavioural intervention programme for addressing anxiety in 10- to 11-year-olds using short classroom activities in Japan: a quasi-experimental study

Study: Without more data, a black hole’s origins can be “spun” in any direction

Current measurements of black holes are not enough to nail down how the invisible giants form in the universe, researchers say

Peer-Reviewed Publication

MASSACHUSETTS INSTITUTE OF TECHNOLOGY

Clues to a black hole’s origins can be found in the way it spins. This is especially true for binaries, in which two black holes circle close together before merging. The spin and tilt of the respective black holes just before they merge can reveal whether the invisible giants arose from a quiet galactic disk or a more dynamic cluster of stars.

Astronomers are hoping to tease out which of these origin stories is more likely by analyzing the 69 confirmed binaries detected to date. But a new study finds that for now, the current catalog of binaries is not enough to reveal anything fundamental about how black holes form.

In a study appearing in the journal Astronomy and Astrophysics Letters, MIT physicists show that when all the known binaries and their spins are worked into models of black hole formation, the conclusions can look very different, depending on the particular model used to interpret the data. 

A black hole’s origins can therefore be “spun” in different ways, depending on a model’s assumptions of how the universe works.

“When you change the model and make it more flexible or make different assumptions, you get a different answer about how black holes formed in the universe,” says study co-author Sylvia Biscoveanu, an MIT graduate student working in the LIGO Laboratory. “We show that people need to be careful because we are not yet at the stage with our data where we can believe what the model tells us.”

The study’s co-authors include Colm Talbot, an MIT postdoc; and Salvatore Vitale, an associate professor of physics and a member of the Kavli Institute of Astrophysics and Space Research at MIT.

A tale of two origins

Black holes in binary systems are thought to arise via one of two paths. The first is through “field binary evolution,” in which two stars evolve together and eventually explode in supernovae, leaving behind two black holes that continue circling in a binary system. In this scenario, the black holes should have relatively aligned spins, as they would have had time — first as stars, then black holes — to pull and tug each other into similar orientations. If a binary’s black holes have roughly the same spin, scientists believe they must have evolved in a relatively quiet environment, such as a galactic disk.

Black hole binaries can also form through “dynamical assembly,” where two black holes evolve separately, each with its own distinct tilt and spin. By some extreme astrophysical processes, the black holes are eventually brought together, close enough to form a binary system. Such a dynamical pairing would likely occur not in a quiet galactic disk, but in a more dense environment, such as a globular cluster, where the interaction of thousands of stars can knock two black holes together. If a binary’s black holes have randomly oriented spins, they likely formed in a globular cluster.

But what fraction of binaries form through one channel versus the other? The answer, astronomers believe, should lie in data, and particularly, measurements of black hole spins.

To date, astronomers have derived the spins of black holes in 69 binaries, which have been discovered by a network of gravitational-wave detectors including LIGO in the U.S., and its Italian counterpart Virgo. Each detector listens for signs of gravitational waves — very subtle reverberations through space-time that are left over from extreme, astrophysical events such as the merging of massive black holes.

With each binary detection, astronomers have estimated the respective black hole’s properties, including their mass and spin. They have worked the spin measurements into a generally accepted model of black hole formation, and found signs that binaries could have both a preferred, aligned spin, as well as random spins. That is, the universe could produce binaries in both galactic disks and globular clusters.

“But we wanted to know, do we have enough data to make this distinction?” Biscoveanu says. “And it turns out, things are messy and uncertain, and it’s harder than it looks.”

Spinning the data

In their new study, the MIT team tested whether the same data would yield the same conclusions when worked into slightly different theoretical models of how black holes form.

The team first reproduced LIGO’s spin measurements in a widely used model of black hole formation. This model assumes that a fraction of binaries in the universe prefer to produce black holes with aligned spins, where the rest of the binaries have random spins. They found that the data appeared to agree with this model’s assumptions and showed a peak where the model predicted there should be more black holes with similar spins.

They then tweaked the model slightly, altering its assumptions such that it predicted a slightly different orientation of preferred black hole spins. When they worked the same data into this tweaked model, they found the data shifted to line up with the new predictions. The data also made similar shifts in 10 other models, each with a different assumption of how black holes prefer to spin.

“Our paper shows that your result depends entirely on how you model your astrophysics, rather than the data itself,” Biscoveanu says.

“We need more data than we thought, if we want to make a claim that is independent of the astrophysical assumptions we make,” Vitale adds.

Just how much more data will astronomers need? Vitale estimates that once the LIGO network starts back up in early 2023, the instruments will detect one new black hole binary every few days. Over the next year, that could add up to hundreds more measurements to add to the data.

“The measurements of the spins we have now are very uncertain,” Vitale says. “But as we build up a lot of them, we can gain better information. Then we can say, no matter the detail of my model, the data always tells me the same story — a story that we could then believe.”

This research was supported in part by the National Science Foundation.

###

Written by Jennifer Chu, MIT News Office

Additional background

Paper: “Spin it as you like: the (lack of a) measurement of the spin tilt
distribution with LIGO-Virgo-KAGRA binary black holes”

https://www.aanda.org/articles/aa/full_html/2022/12/aa45084-22/aa45084-22.html

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ARTICLE TITLE

“Spin it as you like: the (lack of a) measurement of the spin tilt distribution with LIGO-Virgo-KAGRA binary black holes”

Disclaimer: AAAS and EurekA

Curved spacetime in the lab

Researchers simulate an entire family of universes with curvature in ultracold quantum gases

Peer-Reviewed Publication

HEIDELBERG UNIVERSITY

According to Einstein’s Theory of Relativity, space and time are inextricably connected. In our Universe, whose curvature is barely measurable, the structure of this spacetime is fixed. In a laboratory experiment, researchers from Heidelberg University have succeeded in realising an effective spacetime that can be manipulated. In their research on ultracold quantum gases, they were able to simulate an entire family of curved universes to investigate different cosmological scenarios and compare them with the predictions of a quantum field theoretical model. The research results were published in Nature.

The emergence of space and time on cosmic time scales from the Big Bang to the present is the subject of current research that can only be based on the observation of our single Universe. The expansion and curvature of space are essential to cosmological models. In a flat space like our current Universe, the shortest distance between two points is always a straight line. “It is conceivable, however, that our Universe was curved in its early phase. Studying the consequences of a curved spacetime is therefore a pressing question in research,” states Prof. Dr Markus Oberthaler, a researcher at the Kirchhoff Institute for Physics at Heidelberg University. With his “Synthetic Quantum Systems” research group, he developed a quantum field simulator for this purpose.

The quantum field simulator created in the lab consists of a cloud of potassium atoms cooled to just a few nanokelvins above absolute zero. This produces a Bose-Einstein condensate – a special quantum mechanical state of the atomic gas that is reached at very cold temperatures. Prof. Oberthaler explains that the Bose-Einstein condensate is a perfect background against which the smallest excitations, i.e. changes in the energy state of the atoms, become visible. The form of the atomic cloud determines the dimensionality and the properties of spacetime on which these excitations ride like waves. In our Universe, there are three dimensions of space as well as a fourth: time.

In the experiment conducted by the Heidelberg physicists, the atoms are trapped in a thin layer. The excitations can therefore only propagate in two spatial directions – the space is two-dimensional. At the same time, the atomic cloud in the remaining two dimensions can be shaped in almost any way, whereby it is also possible to realise curved spacetimes. The interaction between the atoms can be precisely adjusted by a magnetic field, changing the propagation speed of the wavelike excitations on the Bose-Einstein condensate.

“For the waves on the condensate, the propagation speed depends on the density and the interaction of the atoms. This gives us the opportunity to create conditions like those in an expanding universe,” explains Prof. Dr Stefan Flörchinger. The researcher, who previously worked at Heidelberg University and joined the University of Jena at the beginning of this year, developed the quantum field theoretical model used to quantitatively compare the experimental results.

Using the quantum field simulator, cosmic phenomena, such as the production of particles based on the expansion of space, and even the spacetime curvature can be made measurable. “Cosmological problems normally take place on unimaginably large scales. To be able to specifically study them in the lab opens up entirely new possibilities in research by enabling us to experimentally test new theoretical models,” states Celia Viermann, the primary author of the “Nature” article. “Studying the interplay of curved spacetime and quantum mechanical states in the lab will occupy us for some time to come,” says Markus Oberthaler, whose research group is also part of the STRUCTURES Cluster of Excellence at Ruperto Carola.

The work was conducted as part of Collaborative Research Centre 1225, “Isolated Quantum Systems and Universality in Extreme Conditions” (ISOQUANT), of Heidelberg University.

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JOURNAL

Nature

DOI

10.1038/s41586-022-05313-9 

METHOD OF RESEARCH

Experimental study

SUBJECT OF RESEARCH

Not applicable

ARTICLE TITLE

Quantum field simulator for dynamics in curved spacetime

Tobacco use, incidence of adverse oral health outcomes

JAMA Network Open

Peer-Reviewed Publication

JAMA NETWORK

About The Study: This nationally representative cohort study found associations of current combustible tobacco use with the incidence of adverse oral health outcomes and also found an association between current electronic nicotine delivery systems use and the incidence of bleeding after brushing or flossing. These findings highlight the importance of longitudinal studies and emphasize the continued importance of tobacco cessation counseling and resources in clinical practice. 

Authors: Marushka L. Silveira, B.D.S., M.P.H., Ph.D., of the National Institutes of Health in Bethesda, Maryland, is the corresponding author. 

To access the embargoed study: Visit our For The Media website at this link https://media.jamanetwork.com/ 

(doi:10.1001/jamanetworkopen.2022.45909)

Editor’s Note: Please see the article for additional information, including other authors, author contributions and affiliations, conflict of interest and financial disclosures, and funding and support.

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About JAMA Network Open: JAMA Network Open is an online-only open access general medical journal from the JAMA Network. On weekdays, the journal publishes peer-reviewed clinical research and commentary in more than 40 medical and health subject areas. Every article is free online from the day of publication.

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