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Preparing the LHC and its injector complex for the 2024 lead-ion run

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Preparing the LHC and its injector complex for the 2024 lead-ion run


Accelerator Report: Preparing the LHC and its injector complex for the 2024 lead-ion run
The current SPS supercycle, which repeats every 43.2 seconds, starts with a proton cycle for the SPS North Area, followed by short lead-ion cycles. Another proton cycle then ends the supercycle. The white lines represent the energy of the beam, the yellow line the number of protons and the blue line the number of lead ions. Credit: CERN

In the early morning of 13 September, the LHC reached a significant milestone, surpassing 100 fb-1 of integrated luminosity delivered to ATLAS and CMS in a single year—a record—and the figure is still rising. Then, LHCb’s integrated luminosity target of 8.5 fb-1 was reached one day later.

Of course, this does not mean that we will cease delivering collisions to the LHCb experiment—the LHC team will do its utmost to further increase the size of LHCb’s dataset.

While the LHC continues to provide proton–proton collisions to the experiments, the injector chain is, simultaneously, providing protons to the fixed target experiments. It is also preparing for the lead-ion physics run, not only in the LHC but also in the SPS North Area and the PS East Area.

After a brief test with magnesium ions from April to May this year, Linac3 was converted back to produce lead ions. The original plan was to inject lead ions into the LEIR machine on 5 August.

However, due to a problem with the high-voltage power supply in a 14.5 GHz generator that feeds the Linac3 source, this was delayed. Following repairs to the generator, Linac3 restarted on 19 August and, that same day, the first lead ions were available for LEIR.

Because of this two-week delay, the LEIR beam commissioning schedule had to be adjusted. Studies to improve LEIR’s performance were canceled, and a fast-tracked plan was introduced to ensure that lead-ion beams were ready in time to be delivered to the SPS.

On 17 September, as planned, the first lead ions were successfully injected and circulating in the SPS. Since the SPS usually operates with a high beam duty cycle and has little flexibility for unscheduled additions, special commissioning blocks for the lead ions were included in the injector schedule for the start of the year.

On 18 and 19 September, from 8 a.m. to 6 p.m., a short ion cycle (14.4 seconds) was added to the SPS supercycle (see image above), allowing the SPS team to perform the first part of the lead-ion beam commissioning in the accelerator. For the next steps, a longer ion cycle (57.6 seconds) is required. However, this long cycle would significantly extend the SPS supercycle, reducing the efficiency for both the protons and the ion beam users.

To manage this efficiently, six dedicated 10-hour commissioning blocks have been scheduled between 1 and 30 November, during which the long ion cycle will be the sole focus of the SPS supercycle. This will allow the team to set up the final lead-ion beam for the LHC, including the slip-stacking process.

Finally, at least two versions of the lead-ion beams will be prepared in the SPS: one of 57.6 seconds for the LHC, incorporating the slip-stacking process; and another for the users in the SPS North Area, which will involve slow extraction but no slip-stacking and will be 25.2 seconds long.

The four-week physics run for the SPS North Area users is scheduled to start on 4 November, followed by the LHC lead-ion physics run on 6 November, which will last 2.5 weeks. The lead-ion physics program in the PS East Area is set to start on 11 December.

Due to the fast-tracked commissioning process in LEIR, valuable time was lost to studying and improving machine performance, as well as addressing issues encountered during the 2023 lead-ion run. However, the LEIR team will use all available time to recover as much as possible of the lost study time between the six dedicated commissioning blocks.

Citation:
Preparing the LHC and its injector complex for the 2024 lead-ion run (2024, September 20)
retrieved 20 September 2024
from https://phys.org/news/2024-09-lhc-injector-complex-ion.html

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Female elephants rumble to say ‘let’s go!’ Namibian study shows males do too, a sign of unexpected social bonds

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Female elephants rumble to say ‘let’s go!’ Namibian study shows males do too, a sign of unexpected social bonds


group of elephants
Credit: Pixabay/CC0 Public Domain

In elephant family groups made up of related females and their young, it is clear that the animals produce vocal sounds to coordinate action. This happens when it’s time to leave a waterhole, for example. The matriarch or dominant female steps away from the waterhole and turns to the direction she intends to move in. Then she flaps her ears as she makes a short call referred to as the “let’s go” rumble.

What follows is a highly coordinated “conversation” of sorts. The female elephants in the group add their own rumbles, each waiting for the previous individual to finish what it has to say first.

Elephants coordinate action so that they can remain together (at least within acoustic range), while moving to the next resource. It is safer for females and their offspring to travel as a group to protect their young from potential predation.

Male elephants also live in groups, often referred to as bachelor herds. But it’s never been clear how they coordinate their actions. Previous research using camera trap data seemed to show that subordinate males simply followed older males to resources.

Ever since my husband and I worked for the Namibian government from 1992-1995, we have been returning to Mushara waterhole to study the resident elephants. Since 2004, I have brought a team of researchers to help me, and we have returned every dry season to follow the lives of known individual elephants to learn about their group dynamics, coordination and communication.

Our observations of a group of male elephants in Etosha showed that they use the same vocal coordination as females to trigger the action of leaving the waterhole. And the three elephants that most often initiated the “let’s go” rumbles were highly socially integrated. One of them was the most dominant in the group.

This active coordination of male movements, triggered by vocalizations, has never been documented before. It was also surprising because previously it was thought that male groups didn’t have tight social bonds.

Our findings suggest that male elephant society is much richer than previously thought.

Recording elephants in Namibia

Our study of elephant “let’s go” rumbles at Mushara waterhole started in 2005. We know the individual animals and their hierarchy. We recorded their vocalizations and behavior when they left the waterhole, noting which individuals made the calls and in what order. Each one’s social status and the “signature” structure of its call was also documented.

The calls are infrasonic—humans can’t hear the fundamental frequency but our high-tech microphones could pick them up so we could analyze them later.

Male elephant sounds recorded by extremely sensitive microphone.

The recordings and observations showed that older males invited younger ones to follow them when they left the waterhole, in the same way as females do. The senior male elephant gave a “let’s go” rumble and then each male contributed its own response in a highly coordinated, synchronized fashion.

The involvement of many group members in the “vocal bout” suggests a consensus decision-making process about the timing and direction of the group departure, even though a lead individual initiated the event.

Even more fascinating is that the responses had a musical quality, in the sense that each elephant manipulates its larynx to modify the sound it makes relative to the sound it hears from another elephant. We didn’t expect this and are looking into it more deeply.

Male elephant society

Another reason this finding is exciting is that it provides further evidence that coming-of-age males have a social resource that they can access after they leave the security of family.

Male elephants grow up in a highly social environment within family groups. As youngsters, they are always around their brothers, cousins and other extended family. Once they leave their families at the age of 12-15 years, they suddenly find themselves in a whole new social situation—alone until they can forge ties with other independent males and groups of males within the population.

This isn’t always a straightforward process, and often older males aren’t so interested in dealing with socially needy young males. But a few of the older, social bulls in the Mushara region of Etosha National Park do behave as if they have an interest in taking these young males under their wing.

Mentorship is critical for young male elephants. They seek out elders and young adults that are inclined to look after their well-being. It is truly remarkable to witness these “mentor” characters, and to follow their growth as leaders after coming out of known families that we’ve been watching for decades.

There may be safety in numbers for males, but since predation isn’t as much of a factor, the likely goal of keeping the group together may be to better defend a resource, or simply to remain close to bonded individuals when having to forage a great distances from water resources.

Our study highlights the role of socially integrated males in leading and coordinating group activities. It also provides further evidence that the behavior of these individuals is crucial for group cohesion.

Male elephant society is steeped in ritual. This is something I emphasize in my books, Elephant Don and Wild Rituals. This study demonstrates further that male elephant society is even more sophisticated than we had previously imagined.






Male elephant posture and ear flap.

Elephant communication

This study and another recent study (showing that elephants have names for each other) opens the door to a whole new realm of questions regarding the use of nouns (naming) and verbs (“let’s go”), thereby forming a sentence.

The study also provides further evidence of dialects, as the “let’s go” rumbles we recorded in Etosha look very different structurally than previously published rumbles in parks in east Africa.

We intend to further explore the structure of these coordinated vocalizations among both male and female groups of elephants, as well as the extent of vocal manipulation and coordination in different populations.

Provided by
The Conversation


This article is republished from The Conversation under a Creative Commons license. Read the original article.The Conversation

Citation:
Female elephants rumble to say ‘let’s go!’ Namibian study shows males do too, a sign of unexpected social bonds (2024, September 20)
retrieved 20 September 2024
from https://phys.org/news/2024-09-female-elephants-rumble-namibian-males.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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Physicist reveals tailwind has negligible effect on cycling speed

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Physicist reveals tailwind has negligible effect on cycling speed


What role does a tailwind play in cycling's 'Everesting'?
Author Martin Bier in an aerodynamic tuck, a cycling position that reduces wind resistance. Credit: Martin Bier

Within the cycling realm, “to Everest” involves riding up and down the same mountain until your ascents total the elevation of Mt. Everest—8,848 meters.

After a new cycling “Everesting” record was set a few years ago, a debate ensued on social media about the strong tailwind the cyclist had on climbs—5.5 meters per second (20 kilometers per hour or 12 miles per hour)—when he set the record. To what extent did the tailwind help him? Should limits be set on the allowed windspeed?

Martin Bier, a physics professor at East Carolina University in North Carolina, became intrigued by this debate and decided to explore the physics, and a little project ensued. In the American Journal of Physics, he shares his finding that ultimately, the wind turns out to be of negligible consequence.

First, a little background: From a physics perspective, cycling is easier to comprehend than running.

“In running, the motion of the legs is repeatedly accelerated and decelerated, and the runner’s center of mass moves up and down,” said Bier. “Cycling uses ‘rolling,’ which is much smoother and faster, and more efficient—all of the work is purely against gravity and friction.”

But there’s something odd about air resistance. The force of air friction you fight goes up with the square of your speed. If air resistance is the main thing limiting your speed—which is true for a cyclist on flat ground or going downhill—then to double your speed, you need four times the force. Tripling your speed requires nine times as much force. But, on the other hand, when cycling uphill, your speed is much slower, so air resistance isn’t a big factor.

“When you’re riding up a hill and fighting gravity, doubling your power input means doubling your speed. In bike races, attacks occur on climbs because it’s where your extra effort gets you a bigger gap.”

On a solo Everesting effort, calculations are straightforward. A rider isn’t getting an aerodynamic draft from another rider ahead of them. The inputs are simply watts, gravity, and resistance.

“Naively, you may think that a strong tailwind can compensate for an uphill slope,” said Bier. “You then ride up the hill as if it’s a flat road, and on the way down the headwind and downward slope balance out and again give you the feel of a flat road. But it doesn’t work—the square I mentioned earlier wreaks havoc.”

His work shows the tailwind may help a little on the climb, but most of the work on the way up is the fight against gravity. The subsequent descent is fast and lasts a much shorter time, while the headwind there actually has a huge effect. And the speed on a descent is high—about 80 kph (49.7 mph).

“Air resistance goes with the square of the speed, which leads to the headwind on the descent and causes a big reduction in speed,” Bier said. “The wind boost on the ascent is canceled out.”

The obvious implication of Bier’s work is that there’s no point in waiting for the ideal wind if you want to improve your Everesting time.

“There are no easy tricks,” he said. “If you want to be a better Everester, you need to lose weight and generate more watts (exercise). This is what matters—there’s no way around it.”

More information:
The physics of ‘Everesting’ on a bicycle, American Journal of Physics (2024). DOI: 10.1119/5.0131679

Citation:
Physicist reveals tailwind has negligible effect on cycling speed (2024, September 20)
retrieved 20 September 2024
from https://phys.org/news/2024-09-physicist-reveals-tailwind-negligible-effect.html

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Analysis finds flaw in US plan to cut vehicle emissions—and possible solution

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Analysis finds flaw in US plan to cut vehicle emissions—and possible solution


by Anne J. Manning, Harvard Gazette

hybrid vehicle
Credit: Unsplash/CC0 Public Domain

A new analysis led by a group of college researchers finds the U.S. will fall short of its recently finalized target for reducing vehicle emissions by nearly 15 percent over the next decade because of unrealistic goals for increasing electric-vehicle production. But adding more hybrids to the mix could help.

The study, published in Nature Communications, finds the U.S. won’t come close to its EV sales target by 2032, due mostly to bottlenecks in supply chains for crucial minerals like graphite and cobalt. Failing to correct these issues would amount to nearly 60 million extra tons of carbon dioxide emissions over the next eight years.

Paper co-author and economics concentrator Megan Yeo ’25 said the team sought to break down the EPA’s stringent new emissions goals and assess whether they were realistic.

“First we asked, ‘How many EVs need to be sold to reach that target?’ After that, we looked at different scenarios,” said Yeo, who co-authored the paper with Harvard Law School senior research associate Ashley Nunes, along with first author Lucas Woodley ’23 and Chung Yi See ’22.

The researchers found that meeting the new standards would require replacing at least 10.21 million internal combustion engine vehicles with EVs between 2027 and 2032. But they estimated the U.S. and its allies would only be able to support the manufacture of about 5.09 million EVs during that period, falling short of the goal by about half.

Manufacturing EVs and their rechargeable batteries requires large amounts of minerals including cobalt, graphite, lithium, and nickel. The U.S. and its allies likely have ample reserves of the raw materials.

The problem is production capacity—the ability to adequately mine and refine the materials. The challenge is particularly acute for graphite, which has not been mined domestically since the mid-20th century.

Analysis finds flaw in US plan to cut vehicle emissions—and possible solution
Overview of EV sales scenarios and impact of mineral supply constraints. Credit: Nature Communications (2024). DOI: 10.1038/s41467-024-51152-9

The team scoured for solutions, including rethinking emissions goals by producing more hybrid-electric vehicles. HEVs require fewer mineral resources but have reduced tailpipe emissions, offering a way to close the gap on emissions and expand the government’s focus beyond EVs.

“We suggest exploring HEVs as an alternative pathway,” Yeo said.

According to Nunes, another of the study’s takeaways is that the U.S. might be able to build enough electric cars if it leaned more heavily on China for mineral resources. But U.S. lawmakers are wary of this approach for national security reasons.

“Americans may have to ask, what do we value more—fewer emissions or energy security?” Nunes said.

Singapore native Yeo said she aspires to be a public-sector economist in her home country and that joining Nunes’ research group to work on the EV analysis opened her eyes to the rigors and constraints of evaluating public policy.

“Setting lower and upper bounds for different scenarios, and running through alternative possibilities, robustness checks, and assumptions, were all very valuable skills for me to learn,” Yeo said.

Working in the Nunes group, there’s “never a dull moment,” she continued, with multiple projects related to EVs and other transportation-sector climate goals in the works.

The paper’s other co-authors were Peter Cook and Seaver Wang of the Breakthrough Institute, Laurena Huh of MIT, and Daniel Palmer, a high school student at the Groton School who participated in Harvard’s precollege and secondary school programs.

More information:
Lucas Woodley et al, Climate impacts of critical mineral supply chain bottlenecks for electric vehicle deployment, Nature Communications (2024). DOI: 10.1038/s41467-024-51152-9

Provided by
Harvard Gazette

This story is published courtesy of the Harvard Gazette, Harvard University’s official newspaper. For additional university news, visit Harvard.edu.

Citation:
Analysis finds flaw in US plan to cut vehicle emissions—and possible solution (2024, September 20)
retrieved 20 September 2024
from https://techxplore.com/news/2024-09-analysis-flaw-vehicle-emissions-solution.html

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Black garden ants modify the structure of their nests to mitigate fungal infection spread

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Black garden ants modify the structure of their nests to mitigate fungal infection spread


Black garden ants modify the structure of their nests to mitigate fungal infection spread
Experimental protocol and nest network extraction. Credit: bioRxiv (2024). DOI: 10.1101/2024.08.30.610481

A small team of biologists at the University of Bristol has found that black garden ants modify the physical structure of their nests to mitigate infection spread. The group has written a paper describing the experiments they conducted with black garden ants and fungal infections in their lab and posted it on the bioRxiv preprint server.

Prior research has shown that some animals change their behavior to avoid spreading infections, whether they be viral, bacterial or fungal. Among those, only humans have been found to alter their surroundings as a way to further protect themselves—people might close off parts of their house, for example, or establish quarantine zones within hospital areas.

In this new study, the research team found an instance of an insect altering its nest to deter the spread of an infecting fungus.

To learn more about how insects, such as ants, attempt to prevent the spread of an infection among members of a nest, the research team went into the field and collected black garden ants—enough to set up 20 colonies in their lab, each in its own glass enclosure.

After giving the ants a single day to acclimate themselves to their new environment, the researchers added 20 more ants to each colony—half of which were infected with a fungus known to spread among the ants.

The research team then set up cameras to record the behavior of the ants and micro-CT scanners to study the nature of the nest tunnels that the ants dug beneath the soil.







Credit: bioRxiv (2024). DOI: 10.1101/2024.08.30.610481

The team found that in the colonies with the infected ants, new tunnels were dug faster than in those not infected. After six days, the spacing between the tunnels was farther apart in the infected nest as well.

The ants in the exposed colonies also placed their queen, food and brooding area in a less central location. And finally, those ants that were infected tended to spend most of their time on the surface, rather than underground with their nestmates.

The researchers next used disease transmission simulations to speed up the process of disease spread and found that the techniques used by the ants did indeed reduce the fungal load in the colony, helping the nest survive.

More information:
Luke Leckie et al, Architectural Immunity: ants alter their nest networks to fight epidemics, bioRxiv (2024). DOI: 10.1101/2024.08.30.610481. www.biorxiv.org/content/10.110 … /2024.08.30.610481v1

© 2024 Science X Network

Citation:
Black garden ants modify the structure of their nests to mitigate fungal infection spread (2024, September 20)
retrieved 20 September 2024
from https://phys.org/news/2024-09-black-garden-ants-mitigate-fungal.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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