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The effects of smartphone use on parenting

Parents may worry that spending time on their smartphones has a negative impact on their relationships with their children. However, a new comprehensive analysis published in the Journal of Child Psychology and Psychiatry found that this is unlikely to be the case.

In the analysis of data from 3, 659 parent-based surveys, the authors tested 84 different possibilities to assess whether smartphone use was associated with parenting, and they found little evidence. Accordingly, they explored whether the effect of phone use on parenting depended on whether it displaced time with family and was associated with family conflict.

At low levels of displacing time with family, more smartphone use was associated with better (not worse) parenting. The authors noted that, especially considering diverse family environments, smartphones play multiple roles in family life, and when not heavily impacting on family time, may have a positive role in parenting.

“The challenge with much of the technology-family literature is that is has mainly stemmed from an assumption of risk and problems. As a result, small and uneven findings can become the focus of media, policymakers, and parents,” said lead author Kathryn L. Modecki, PhD, of Menzies Health Institute Queensland, Griffith University, in Australia. “This is an issue because it can cloud our insight as we focus on ways to meaningfully assist parents and families to enhance positive outcomes.” Thus, Dr. Modecki and her colleagues used a transparent approach that mapped a myriad of ways that smartphones could link to family wellbeing. “We found very little evidence of problems and hope these data help move us towards more constructive and nuanced conversations around families’ diverse experiences with technology, actual risks associated with parenting, and where we can best support,” she said.

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Plastic recycling from Europe is being dumped in Asian waters

New research from NUI Galway and the University of Limerick has for the first time quantified the volume of plastic from European countries (EU, UK, Switzerland and Norway) that contributes to ocean littering from exported recycling.

While European countries have developed world-leading waste management infrastructure, 46% of European separated plastic waste is exported outside the country of origin. A large share of this plastic is transported thousands of kilometres to countries with poor waste management practices, largely located in Southeast Asia. Once in these countries, a large share of the waste is rejected from recycling streams into overstretched local waste management systems that have been found to contribute significantly to ocean littering.

This new research, published in the scientific journal Environment International, estimated the best-case, average, and worst-case scenarios of ocean debris pathways from exported recycling in 2017. The results estimated a range between 32,115 — 180,558 tonnes, or 1 — 7% of all exported European polyethylene, which ended up in the ocean. Polyethylene is one of the most common types of plastic in Europe, and the results showed that countries such as the UK, Slovenia, and Italy are exporting a higher share of plastic outside of Europe and see a higher share of their recyclable plastic waste end up as ocean debris.

Speaking today, George Bishop, lead author of the study said: “The results indicate an important and previously undocumented pathway of plastic debris entering the oceans, which will have considerable environmental and social impacts on marine ecosystems and coastal communities.”

Using detailed international trade data and data on waste management in destination countries, the study modelled the fate of all polyethylene exported for recycling from Europe, accounting for different fates ranging from successful conversion into recycled resins, or ending up as landfill, incineration, or ocean debris.

Dr David Styles, a lecturer at the University of Limerick and co-author, explains, “Given that such a large share of waste destined for recycling is exported, with poor downstream traceability, this study suggests that ‘true’ recycling rates may deviate significantly from rates reported by municipalities and countries where the waste originates. In fact, our study found that up to 31% of the exported plastic wasn’t actually recycled at all.”

The study was part of the Science Foundation Ireland funded, ‘Innovative Energy Technologies for Bioenergy, Biofuels and a Sustainable Irish Bioeconomy: IETSBIO3’ led by Professor Piet Lens, Established Professor of New Energy Technologies at the National University of Ireland, Galway.

Professor Lens added: “To successfully move towards a more circular economy, European municipalities and waste management companies need to be held accountable for the final fate of “recycled” waste. Our study highlights the lack of available data on plastic waste and the need to consider extended audit trails, or “on-shoring” of recycling activities as part of emerging regulations around trade in plastic waste.”

The authors caution that these findings should not discourage people to recycle as it remains the best waste management treatment, environmentally speaking. However, there is considerable work to be done to improve aspects of these plastic recycling chains, to reduce the ‘leakage’ of these systems.

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Could your computer please be more polite? Thank you

PITTSBURGH–In a tense time when a pandemic rages, politicians wrangle for votes and protesters demand racial justice, a little politeness and courtesy go a long way. Now researchers at Carnegie Mellon University have developed an automated method for making communications more polite.

Specifically, the method takes nonpolite directives or requests — those that use either impolite or neutral language — and restructures them or adds words to make them more well-mannered. “Send me the data,” for instance, might become “Could you please send me the data?”

The researchers will present their study on politeness transfer at the Association for Computational Linguistics annual meeting, which will be held virtually beginning July 5.

The idea of transferring a style or sentiment from one communication to another — turning negative statements positive, for instance — is something language technologists have been doing for some time. Shrimai Prabhumoye, a Ph.D. student in CMU’s Language Technologies Institute (LTI), said performing politeness transfer has long been a goal.

“It is extremely relevant for some applications, such as if you want to make your emails or chatbot sound more polite or if you’re writing a blog,” she said. “But we could never find the right data to perform this task.”

She and LTI master’s students Aman Madaan, Amrith Setlur and Tanmay Parekh solved that problem by generating a dataset of 1.39 million sentences labeled for politeness, which they used for their experiments.

The source of these sentences might seem surprising. They were derived from emails exchanged by employees of Enron, a Texas-based energy company that, until its demise in 2001, was better known for corporate fraud and corruption than for social niceties. But half a million corporate emails became public as a result of lawsuits surrounding Enron’s fraud scandal and subsequently have been used as a dataset for a variety of research projects.

But even with a dataset, the researchers were challenged simply to define politeness.

“It’s not just about using words such as ‘please’ and ‘thank you,'” Prabhumoye said. Sometimes, it means making language a bit less direct, so that instead of saying “you should do X,” the sentence becomes something like “let us do X.”

And politeness varies from one culture to the next. It’s common for native North Americans to use “please” in requests to close friends, but in Arab culture it would be considered awkward, if not rude. For their study, the CMU researchers restricted their work to speakers of North American English in a formal setting.

The politeness dataset was analyzed to determine the frequency and distribution of words in the polite and nonpolite sentences. Then the team developed a “tag and generate” pipeline to perform politeness transfers. First, impolite or nonpolite words or phrases are tagged and then a text generator replaces each tagged item. The system takes care not to change the meaning of the sentence.

“It’s not just about cleaning up swear words,” Prabhumoye said of the process. Initially, the system had a tendency to simply add words to sentences, such as “please” or “sorry.” If “Please help me” was considered polite, the system considered “Please please please help me” even more polite.

But over time the scoring system became more realistic and the changes became subtler. First person singular pronouns, such as I, me and mine, were replaced by first person plural pronouns, such as we, us and our. And rather than position “please” at the beginning of the sentence, the system learned to insert it within the sentence: “Could you please send me the file?”

Prabhumoye said the researchers have released their labeled dataset for use by other researchers, hoping to encourage them to further study politeness.

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In addition to the students, the study’s co-authors included several professors from the LTI and the Machine Learning Department — Barnabas Poczos, Graham Neubig, Yiming Yang, Ruslan Salakhutdinov and Alan Black. The Air Force Research Laboratory, Office of Naval Research, National Science Foundation, Apple and NVIDIA supported this research.

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10 Top URL Shortener APIs

There comes a time in every web developer’s life when they will need to shorten a URL. The reason could be to hide tracking links, make a link fit into a Tweet, make a more memorable link, make a link smaller to put it in print, add branding to a link, run an A/B test, retarget a link for market research, or maybe swap out a link at a later time (link rotation).

Developers wishing to take advantage of URL shortening technology will want to seek out URL Shortener APIs.

What is a URL Shortener API?

A URL Shortener API, or Application Programming Interface, will allow a developer to integrate with URL shortening services and create applications, or add those functions to existing applications.

The best place to find these APIs is in the URL Shortener category in the ProgrammableWeb directory. There, developers can discover useful programming resources such as APIs for shortening URLs.

In this article, we detail the ten most popular URL Shortener APIs, based on page views in the ProgrammableWeb website.

1. Bitly API

Bitly allows users to shorten URLs, share, and track links. Bitly’s function can be accessed through their website, bookmarklets, and this open APITrack this API. The Bit.ly service enables users to customize shortened links using their brand names or other words.

Bitly is an enterprise-class URL shortener with an API. Screenshot: Bitly

2. Ow.ly API

Ow.ly is a link shortening and expanding application that allows users to either shrink or expand URLs for web pages, uploaded photos, and uploaded documents. The Ow.ly APITrack this API allows developers to integrate the functionality of Ow.ly with other applications with methods to shorten URLs, expand URLs, retrieve information about URLs, and access statistics of clicks. Ow.ly is part of Hootsuite social media management tools.

3. Tiny-URL API

The Tiny-URL Open APITrack this API is a service that allows users to shorten URLs. Rather than provide a single URL shortener, Tiny-URL connects to over 80 other services. The API uses RESTful protocol and responses are formatted in either XML, JSON or TXT.

4. Hide URI API

Hide URI adds URL shortener capabilities to applications. The REST APITrack this API returns JSON objects containing the shortened URLs.

5. QRTag API

QRtag generates a QR code for a given URL. The QRtag.net APITrack this API returns QR codes in a PDF, or SVG or PNG images. To use the API, embed it as a normal image.

6. VURL API

The VURL APITrack this API can be integrated with applications to automate URL shortener capabilities. URLs sent to VURL.com must be encoded.

7. CU8.in API

Cu8.in APITrack this API provides a free URL shortener API service without registration. Users can quickly shorten URL and create custom links with just a few clicks in less than 10 seconds.

8. Rebrandly API

Rebrandly is a custom URL shortener. With the Rebrandly APITrack this API users can build in features to applications to create, track and share branded short links.

9. CHOGOON URL Shortener API

CHOGOON provides APIs for developers. The CHOGOON URL Shortener APITrack this API returns a JSON formatted response of a requested URL to shorten.

10. Mgnet.me shortener API

Mgnet.me is a shortener for magnet: URI scheme. Magnet links are primarily used for referencing resources available for download via peer-to-peer networks. The Mgnet.me API provides the same functionality in XML, JSON and text output formats.

Check out the URL Shortener category for more than 120 APIs, plus SDKs and Source Code Samples.

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Stiffer roadways could improve truck fuel efficiency

Every time you hear a deep rumble and feel your house shake when a big truck roars by, that’s partly because the weight of heavy vehicles causes a slight deflection in the road surface under them. It’s enough of a dip to make a difference to the trucks’ overall fuel efficiency.

Now, a theoretical study by MIT researchers suggests that small changes in roadway paving practices could reduce that efficiency loss, potentially eliminating a half-percent of the total greenhouse gas emissions from the transportation sector, at little to no cost.

The findings are detailed in a paper in the journal Transportation Research Record, by MIT postdoc Hessam Azarijafari, research scientist Jeremy Gregory, and principal research scientist in the Materials Research Laboratory Randolph Kirchain. The study examined state-by-state data on climate conditions, road lengths, materials properties, and road usage, and modeled different scenarios for pavement resurfacing practices.

They found that that one key to improving mileage efficiency is to make pavements that are stiffer, Kirchain explains. That reduces the amount of deflection, which reduces wear on the road but also reduces the slightly uphill motion the vehicle constantly has to make to rise out of its own depression in the road.

“When we as individuals walk on pavements, they seem like perfectly rigid things. They’re not responding to us,” he says. “But for trucks, that is not the case. There is enough of a deflection in that surface that some amount of energy is expended to overcome the little divot that you create as you drive along.” He likens it to the difference between walking on a hard surface versus walking on sand, which takes more effort because you sink in with each step.

Looking to the future, Kirchain says that while projections show a slight decline in passenger car travel over coming decades, they show an increase in truck travel for freight delivery — the kind where pavement deflection could be a factor in overall efficiency.

There are several ways to make roadways stiffer, the researchers say. One way is to add a very small amount of synthetic fibers or carbon nanotubes to the mix when laying asphalt. Just a tenth of a percent of the inexpensive material could dramatically improve its stiffness, they say. Another way of increasing rigidity is simply to adjust the grading of the different sizes of aggregate used in the mix, to allow for a denser overall mix with more rock and less binder.

“If there are high quality local materials available” to use in the asphalt or concrete mix, “we can use them to improve the stiffness, or we can just adjust the grading of the aggregates that we are using for these pavements,” says Azarijafari. And adding different fibers is “very inexpensive compared to the total cost of the mixture, but it can change the stiffness properties of the mixture significantly.”

Yet another way is to switch from asphalt pavement surfaces to concrete, which has a higher initial cost but is more durable, leading to equal or lower total lifecycle costs. Many road surfaces in northern U.S. states already use concrete, but asphalt is more prevalent in the south. There, it makes even more of a difference, because asphalt is especially subject to deflection in hot weather, whereas concrete surfaces are relatively unaffected by heat. Just upgrading the road surfaces in Texas alone, the study showed, could make a significant impact because of the state’s large network of asphalt roads and its high temperatures.

Kirchain, who is co-director of MIT’s Concrete Sustainability Hub, says that in carrying out this study, the team is “trying to understand what are some of the systemic environmental and economic impacts that are associated with a change to the use of concrete in particular in the pavement system.”

Even though the effects of pavement deflection may seem tiny, he says, “when you take into account the fact that the pavement is going to be there, with thousands of cars driving over it every day, for dozens of years, so a small effect on each one of those vehicles adds up to a significant amount of emissions over the years.” For purposes of this study, they looked at total emissions over the next 50 years and considered the reductions that would be achieved by improving anywhere from 2 percent of road surfaces to 10 percent each year.

With a 10 percent improvement rate, they calculated, a total of 440 megatons of carbon dioxide-equivalent emissions would be avoided over the 50 years, which is about 0.5 percent of total transportation-related emissions for this period.

The proposal may face some challenges, because changing the mix of materials in asphalt might affect its workability in the field, perhaps requiring adjustments to the equipment used. “That change in the field processing would have some cost to it as well,” Kirchain says.

But overall, implementing such changes could in many cases be as simple as changing the specifications required by state or local highway authorities. “These kinds of effects could be considered as part of the performance that’s trying to be managed,” Kirchain says. “It largely would be a choice from the state’s perspective, that either fuel use or climate impact would be something that would be included in the management, as opposed to just the surface performance of the system.”

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Liquid metals break down organic fuels into ultra-thin graphitic sheets

For the first time, FLEET researchers at UNSW, Sydney show the synthesis of ultra-thin graphitic materials at room temperature using organic fuels (which can be as simple as basic alcohols such as ethanol).

Graphitic materials, such as graphene, are ultra-thin sheets of carbon compounds that are sought after materials with great promises for battery storage, solar cells, touch panels and even more recently fillers for polymers.

These researchers were able to synthesize ultra-thin carbon-based materials on the surface of liquid metals at room temperature electrochemically. Before this report, others had shown electro-formation of such carbon-based materials only by transferring sheets onto the electrodes or electrode exfoliation of naturally-occurring carbon crystals from mines.

“Using gallium liquid metal, we could catalytically break down the fuels and form carbon-carbon bonds (the base of graphitic sheets) from organic fuels at room temperature. The ultra-smooth surface of liquid metals could then template atomically-thin carbon based sheets. Removal of these sheets was easy as they do not stick to the liquid metal surface,” suggested Prof Kalantar-Zadeh, the lead of this project and the Director of the Centre for Advanced Solid and Liquid based Electronics and Optics (CASLEO) at UNSW.

“It is simple. Why has room temperature electro-synthesis of two-dimensional graphitic materials not been achieved before? We cannot offer a definitive answer. Perhaps disregarding ultra-catalysts such as liquid metals and too much emphasis on solid electrodes which are inherently not smooth.” added Dr Mohannad Mayyas the first author of the paper.

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First optical measurements of Milky Way’s Fermi Bubbles probe their origin

Using the Wisconsin H-Alpha Mapper telescope, astronomers have for the first time measured the Fermi Bubbles in the visible light spectrum. The Fermi Bubbles are two enormous outflows of high-energy gas that emanate from the Milky Way and the finding refines our understanding of the properties of these mysterious blobs.

The research team from the University of Wisconsin-Madison, UW-Whitewater and Embry-Riddle Aeronautical University measured the emission of light from hydrogen and nitrogen in the Fermi Bubbles at the same position as recent ultraviolet absorption measurements made by the Hubble Telescope.

“We combined those two measurements of emission and absorption to estimate the density, pressure and temperature of the ionized gas, and that lets us better understand where this gas is coming from,” says Dhanesh Krishnarao, lead author of the new study and an astronomy graduate student at UW-Madison.

The researchers announced their findings June 3 at the 236th meeting of the American Astronomical Society, which was held virtually for the first time since 1899, in response to the COVID-19 pandemic.

Extending 25,000 light years both above and below the center of the Milky Way, the Fermi Bubbles were discovered in 2010 by the Fermi Gamma Ray Telescope. These faint but highly energetic outflows of gas are racing away from the center of the Milky Way at millions of miles per hour. But while the origin of the phenomenon has been inferred to date back several million years ago, the events that produced the bubbles remain a mystery.

Now, with new measurements of the density and pressure of the ionized gas, researchers can test models of the Fermi Bubbles against observations.

“The other significant thing is that we now have the possibility of measuring the density and pressure and the velocity structure in many locations,” with the all-sky WHAM telescope, says Bob Benjamin, a professor of astronomy at UW-Whitewater and co-author of the study. “We can do an extensive mapping effort across the Fermi Bubbles above and below the plane of the galaxy to see if the models that people have developed are holding up. Because, unlike the ultraviolet data, we’re not limited to just specific lines of sight.”

Matt Haffner, professor of physics and astronomy at Embry-Riddle Aeronautical University and a co-author of the report, says the work demonstrates the usefulness of the WHAM telescope, developed at UW-Madison, to tell us more about the workings of the Milky Way. The central region of our home galaxy has long been difficult to study because of gas blocking out view, but WHAM has provided new opportunities to gather the kind of information we have for distant galaxies.

“There are regions of the galaxy we can target with very sensitive instruments like WHAM to get this kind of new information toward the center that previously we are only able to do in the infrared and radio,” says Haffner. “We can make comparisons to other galaxies by making the same kind of measurements towards the center of the Milky Way.”

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NASA astronauts launch from America in historic test flight of SpaceX Crew Dragon

For the first time in history, NASA astronauts have launched from American soil in a commercially built and operated American crew spacecraft on its way to the International Space Station. The SpaceX Crew Dragon spacecraft carrying NASA astronauts Robert Behnken and Douglas Hurley lifted off at 3:22 p.m. EDT Saturday on the company’s Falcon 9 rocket from Launch Complex 39A at NASA’s Kennedy Space Center in Florida.

“Today a new era in human spaceflight begins as we once again launched American astronauts on American rockets from American soil on their way to the International Space Station, our national lab orbiting Earth,” said NASA Administrator Jim Bridenstine. “I thank and congratulate Bob Behnken, Doug Hurley, and the SpaceX and NASA teams for this significant achievement for the United States. The launch of this commercial space system designed for humans is a phenomenal demonstration of American excellence and is an important step on our path to expand human exploration to the Moon and Mars.”

Known as NASA’s SpaceX Demo-2, the mission is an end-to-end test flight to validate the SpaceX crew transportation system, including launch, in-orbit, docking and landing operations. This is SpaceX’s second spaceflight test of its Crew Dragon and its first test with astronauts aboard, which will pave the way for its certification for regular crew flights to the station as part of NASA’s Commercial Crew Program.

“This is a dream come true for me and everyone at SpaceX,” said Elon Musk, chief engineer at SpaceX. “It is the culmination of an incredible amount of work by the SpaceX team, by NASA and by a number of other partners in the process of making this happen. You can look at this as the results of a hundred thousand people roughly when you add up all the suppliers and everyone working incredibly hard to make this day happen.”

The program demonstrates NASA’s commitment to investing in commercial companies through public-private partnerships and builds on the success of American companies, including SpaceX, already delivering cargo to the space station.

“It’s difficult to put into words how proud I am of the people who got us here today,” said Kathy Lueders, NASA’s Commercial Crew Program manager. “When I think about all of the challenges overcome — from design and testing, to paper reviews, to working from home during a pandemic and balancing family demands with this critical mission — I am simply amazed at what the NASA and SpaceX teams have accomplished together. This is just the beginning; I will be watching with great anticipation as Bob and Doug get ready to dock to the space station tomorrow, and through every phase of this historic mission.”

SpaceX controlled the launch of the Falcon 9 rocket from Kennedy’s Launch Control Center Firing Room 4, the former space shuttle control room, which SpaceX has leased as its primary launch control center. As Crew Dragon ascended into space, SpaceX commanded the spacecraft from its mission control center in Hawthorne, California. NASA teams are monitoring space station operations throughout the flight from Mission Control Center at the agency’s Johnson Space Center in Houston.

The SpaceX Crew Dragon spacecraft is scheduled to dock to the space station at 10:29 a.m. Sunday, May 31. NASA Television and the agency’s website are providing ongoing live coverage of the Crew Dragon’s trip to the orbiting laboratory. Behnken and Hurley will work with SpaceX mission control to verify the spacecraft is performing as intended by testing the environmental control system, the displays and control system, and by maneuvering the thrusters, among other things. The first docking maneuver began Saturday, May 30, at 4:09 p.m., and the spacecraft will begin its close approach to the station at about 8:27 a.m. Sunday, May 31. Crew Dragon is designed to dock autonomously, but the crews onboard the spacecraft and the space station will diligently monitor the performance of the spacecraft as it approaches and docks to the forward port of the station’s Harmony module.

After successfully docking, the crew will be welcomed aboard the International Space Station, where they will become members of the Expedition 63 crew, which currently includes NASA astronaut Chris Cassidy. NASA will continue live coverage through hatch opening and the crew welcoming ceremony. The crew will perform tests on Crew Dragon in addition to conducting research and other tasks with the space station crew.

Three astronauts aboard the International Space Station will participate in a live NASA Television crew news conference from orbit on Monday, June 1, beginning at 11:15 a.m. on NASA TV and the agency’s website (www.nasa.gov/live).

Demo-2 Astronauts

Behnken is the joint operations commander for the mission, responsible for activities such as rendezvous, docking and undocking, as well as Demo-2 activities while the spacecraft is docked to the space station. He was selected as a NASA astronaut in 2000 and has completed two space shuttle flights. Behnken flew STS-123 in March 2008 and STS-130 in February 2010, performing three spacewalks during each mission. Born in St. Anne, Missouri, he has bachelor’s degrees in physics and mechanical engineering from Washington University in St. Louis and earned a master’s and doctorate in mechanical engineering from the California Institute of Technology in Pasadena. Before joining NASA, he was a flight test engineer with the U.S. Air Force.

Hurley is the spacecraft commander for Demo-2, responsible for activities such as launch, landing and recovery. He was selected as an astronaut in 2000 and has completed two spaceflights. Hurley served as pilot and lead robotics operator for both STS‐127 in July 2009 and STS‐135, the final space shuttle mission, in July 2011. The New York native was born in Endicott but considers Apalachin his hometown. He holds a Bachelor of Science degree in civil engineering from Tulane University in New Orleans and graduated from the U.S. Naval Test Pilot School in Patuxent River, Maryland. Before joining NASA, he was a fighter pilot and test pilot in the U.S. Marine Corps.

Mission Objectives

The Demo-2 mission is the final major test before NASA’s Commercial Crew Program certifies Crew Dragon for operational, long-duration missions to the space station. As SpaceX’s final flight test, it will validate all aspects of its crew transportation system, including the Crew Dragon spacecraft, spacesuits, Falcon 9 launch vehicle, launch pad 39A and operations capabilities.

While en route to the station, Behnken and Hurley will take control of Crew Dragon for two manual flight tests, demonstrating their ability to control the spacecraft should an issue with the spacecraft’s automated flight arise. On Saturday, May 30, while the spacecraft is coasting, the crew will test its roll, pitch and yaw. When Crew Dragon is about 1 kilometer (0.6 miles) below the station and moving around to the docking axis, the crew will conduct manual in-orbit demonstrations of the control system in the event it were needed. After pausing, rendezvous will resume and mission managers will make a final decision about whether to proceed to docking as Crew Dragon approaches 20 meters (66 feet).

For operational missions, Crew Dragon will be able to launch as many as four crew members at a time and carry more than 220 pounds of cargo, allowing for an increased number crew members aboard the space station and increasing the time dedicated to research in the unique microgravity environment, as well as returning more science back to Earth.

The Crew Dragon being used for this flight test can stay in orbit about 110 days, and the specific mission duration will be determined once on station based on the readiness of the next commercial crew launch. The operational Crew Dragon spacecraft will be capable of staying in orbit for at least 210 days as a NASA requirement.

At the conclusion of the mission, Behnken and Hurley will board Crew Dragon, which will then autonomously undock, depart the space station, and re-enter Earth’s atmosphere. Upon splashdown off Florida’s Atlantic coast, the crew will be picked up by the SpaceX recovery ship and returned to the dock at Cape Canaveral.

NASA’s Commercial Crew Program is working with SpaceX and Boeing to design, build, test and operate safe, reliable and cost-effective human transportation systems to low-Earth orbit. Both companies are focused on test missions, including abort system demonstrations and crew flight tests, ahead of regularly flying crew missions to the space station. Both companies’ crewed flights will be the first times in history NASA has sent astronauts to space on systems owned, built, tested and operated by private companies.

Learn more about NASA’s Commercial Crew program at: https://www.nasa.gov/commercialcrew

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Nanodevices show how cells change with time, by tracking from the inside

For the first time, scientists have introduced minuscule tracking devices directly into the interior of mammalian cells, giving an unprecedented peek into the processes that govern the beginning of development.

This work on one-cell embryos is set to shift our understanding of the mechanisms that underpin cellular behaviour in general, and may ultimately provide insights into what goes wrong in ageing and disease.

The research, led by Professor Tony Perry from the Department of Biology and Biochemistry at the University of Bath, involved injecting a silicon-based nanodevice together with sperm into the egg cell of a mouse. The result was a healthy, fertilised egg containing a tracking device.

The tiny devices are a little like spiders, complete with eight highly flexible ‘legs’. The legs measure the ‘pulling and pushing’ forces exerted in the cell interior to a very high level of precision, thereby revealing the cellular forces at play and showing how intracellular matter rearranged itself over time.

The nanodevices are incredibly thin — similar to some of the cell’s structural components, and measuring 22 nanometres, making them approximately 100,000 times thinner than a pound coin. This means they have the flexibility to register the movement of the cell’s cytoplasm as the one-cell embryo embarks on its voyage towards becoming a two-cell embryo.

“This is the first glimpse of the physics of any cell on this scale from within,” said Professor Perry. “It’s the first time anyone has seen from the inside how cell material moves around and organises itself.”

WHY PROBE A CELL’S MECHANICAL BEHAVIOUR?

The activity within a cell determines how that cell functions, explains Professor Perry. “The behaviour of intracellular matter is probably as influential to cell behaviour as gene expression,” he said. Until now, however, this complex dance of cellular material has remained largely unstudied. As a result, scientists have been able to identify the elements that make up a cell, but not how the cell interior behaves as a whole.

“From studies in biology and embryology, we know about certain molecules and cellular phenomena, and we have woven this information into a reductionist narrative of how things work, but now this narrative is changing,” said Professor Perry. The narrative was written largely by biologists, who brought with them the questions and tools of biology. What was missing was physics. Physics asks about the forces driving a cell’s behaviour, and provides a top-down approach to finding the answer.

“We can now look at the cell as a whole, not just the nuts and bolts that make it.”

Mouse embryos were chosen for the study because of their relatively large size (they measure 100 microns, or 100-millionths of a metre, in diameter, compared to a regular cell which is only 10 microns [10-millionths of a metre] in diameter). This meant that inside each embryo, there was space for a tracking device.

The researchers made their measurements by examining video recordings taken through a microscope as the embryo developed. “Sometimes the devices were pitched and twisted by forces that were even greater than those inside muscle cells,” said Professor Perry. “At other times, the devices moved very little, showing the cell interior had become calm. There was nothing random about these processes — from the moment you have a one-cell embryo, everything is done in a predictable way. The physics is programmed.”

The results add to an emerging picture of biology that suggests material inside a living cell is not static, but instead changes its properties in a pre-ordained way as the cell performs its function or responds to the environment. The work may one day have implications for our understanding of how cells age or stop working as they should, which is what happens in disease.

The study is published this week in Nature Materials and involved a trans-disciplinary partnership between biologists, materials scientists and physicists based in the UK, Spain and the USA.

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Elucidating the mechanism of a light-driven sodium pump

Researchers at the Paul Scherrer Institute PSI have succeeded for the first time in recording, in action, a light-driven sodium pump from bacterial cells. The findings promise progress in the development of new methods in neurobiology. The researchers used the new X-ray free-electron laser SwissFEL for their investigations. They have published their findings today in the journal Nature.

Sodium, which is contained in ordinary table salt, plays an essential role in the vital processes of most biological cells. Many cells build up a concentration gradient between their interior and the environment. For this purpose, special pumps in the cell membrane transport sodium out of the cell. With the help of such a concentration gradient, cells of the small intestine or the kidneys, for example, absorb certain sugars.

Such sodium pumps are also found in the membranes of bacteria. They belong to the family of the so-called rhodopsins. These are special proteins that are activated by light. For example, rhodopsins transport sodium out of the cell in the case of bacteria living in the ocean, such as Krokinobacter eikastus. The crucial component of rhodopsin is the so-called retinal, a form of vitamin A. It is of central importance for humans, animals, certain algae and many bacteria. In the retina of the human eye, for example, retinal initiates the visual process when it changes shape under the influence of light.

Lightning-fast movie making

Researchers at the Paul Scherrer Institute PSI have now succeeded capturing images of the sodium pump of Krokinobacter eikastus in action and documenting the molecular changes necessary for sodium transport. To do this, they used a technique called serial femtosecond crystallography. A femtosecond is one-quadrillionth of a second; a millisecond is the thousandth part. The sample to be examined — in this case a crystallised sodium pump — is struck first by a laser and then by an X-ray beam. In the case of bacterial rhodopsin, the laser activates the retinal, and the subsequent X-ray beam provides data on structural changes within the entire protein molecule. Since SwissFEL produces 100 of these femtosecond X-ray pulses per second, recordings can be made with high temporal resolution. “We can only achieve temporal resolution in the femtosecond range at PSI with the help of SwissFEL,” says Christopher Milne, who helped to develop the Alvra experimental station where the recordings were made. “One of the challenges is to inject the crystals into the setup so that they meet the pulses of the laser and the X-ray beam with pinpoint accuracy.”

Pump in action

In the current experiment, the time intervals between the laser and X-ray pulses were between 800 femtoseconds and 20 milliseconds. Each X-ray pulse creates a single image of a protein crystal. And just as a cinema film ultimately consists of a large number of individual photographs that are strung together in a series and played back rapidly, the individual pictures obtained with the help of SwissFEL can be put together to form a kind of film.

“The process that we were able to observe in our experiment, and which roughly corresponds to the transport of a sodium ion through a cell membrane, takes a total of 20 milliseconds,” explains Jörg Standfuss, who heads the group for time-resolved crystallography in the Biology and Chemistry Division at PSI . “Besides elucidating the transport process, we were also able to show how the sodium pump achieves its specificity for sodium through small changes in its structure.” This ensures that only sodium ions, and no other positively charged ions, are transported. With these investigations, the researchers also revealed the molecular changes through which the pump prevents sodium ions that have been transported out of the cell from flowing back into it.

Advances in optogenetics and neurobiology

Since sodium concentration differences also play a special role in the way nerve cells conduct stimuli, neurons have powerful sodium pumps in their membranes. If more sodium flows into the cell’s interior, a stimulus is transmitted. These pumps then transport the excess sodium in the cell to the outside again.

Since the sodium pump of Krokinobacter eikastus is driven by light, researchers can now use it for so-called optogenetics. With this technology, cells, in this case nerve cells, are genetically modified in such a way that they can be controlled by light. The pump is installed in nerve cells using methods of molecular genetics. If it is then activated by light, a neuron can no longer transmit stimuli, for example, since this would require an increase in the sodium concentration in the nerve cell. However, bacterial rhodopsin prevents this by continuously transporting sodium out of the cell. Thus active sodium pumps render a neuron inactive.

“If we understand exactly what is going on in the sodium pump of the bacterium, it can help to improve experiments in optogenetics,” says Petr Skopintsev, a PhD candidate in the time-resolved crystallography group. “For example, it can be used to identify variants of bacterial rhodopsin that work more effectively than the form that is usually found in Krokinobacter.” In addition, the researchers hope to gain insights into how individual mutations can change the ion pumps so that they then transport ions other than sodium.

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