Being nursed by a single parent could be an evolutionary strategy to curb the spread of harmful microbes in mammals, according to a novel theory developed by mathematicians.

The rainforests of Malaysia are home to the only known case of a wild male mammal that produces milk. The Dayak fruit bat is a vanishingly rare case of male milk production, despite the fact that the potential for breastfeeding remains in place in most male mammals.

In the 1970s, evolutionary theorists posited that the near absence of lactation in males, even though offspring could benefit from the extra nutrition provided, could be attributed to the uncertainty of paternity: As male mammals can’t be sure they are the biological father, this reduces their evolutionary drive to invest heavily in offspring care, including breastfeeding.

Now, mathematicians from the University of York have suggested a complementary perspective. Their hypothesis, published in Nature Communications, suggests that the reason male mammals don’t breastfeed might be driven by the rich community of microbes that lives in breast milk, which plays an important part in establishing the gut microbiome of the infant.

The theory demonstrates how the transmission of the milk microbiome from both parents would allow harmful microbes to spread through mammalian populations. Maternal-only lactation stops this, as restricting transmission of the milk microbiome to females in effect acts as a sieve, retaining just the microbes with beneficial effects.

One of the authors of the study, Dr. George Constable from the Department of Mathematics at the University of York, said, “We became fascinated with this topic when we read about Azara’s owl monkeys. They turn previous assumptions about why males don’t breastfeed upside down because they are the most devoted dads in the primate world: They do 80–90% of childcare and only hand their babies back to their female partners for nursing.

“When both parents are involved in feeding, the chance of a microbe being passed along and getting an initial foothold in a population is essentially doubled. So our theory suggests selection against the transmission of harmful microbes through mammary milk could be an additional selection pressure against male lactation.”

First author of the study, Dr. Brennen Fagan, working at the Leverhulme Centre for Anthropocene Biodiversity and the Mathematics Department at the University of York, added, “Breast milk is a living substance and it plays a key role in establishing the gut microbiome of mammals, which is a complex ecosystem of bacteria, viruses and fungi, along with their genetic material. This ecosystem plays a crucial role in health, including by helping to protect animals against disease, helping to digest food and in many other ways we are only just discovering.

“While microbes are not inherently harmful or beneficial; it’s their presence and abundance that dictate the overall health of this internal community. A ‘wrong actor’ at the early point of an animal’s life could change the microbiome at a pivotal moment.”

The mathematical model highlights the advantage of being fed by just one parent, but the researchers say it makes evolutionary sense for this to be the mother because there has already been an inevitable transmission of microbes during birth and perhaps also in the womb.

Dr. Constable added, “This theory fits with a pattern of strategies mammals have adopted in an evolutionary bid to limit the spread of potentially harmful elements. Notably, in humans, mitochondrial DNA is exclusively passed down from the mother. This mechanism serves as a natural filter, maintaining genetic integrity by suppressing the proliferation of detrimental mutations. Additionally, the prevalence of monogamous relationships among certain species has been suggested as an adaptive response aimed at minimizing the transmission of sexually transmitted infections (STIs).”

The researchers caution that their hypothesis is not intended as the basis for any judgments about the different ways of feeding human infants.

Dr. Fagan added, “Our model is very much focused on the long-term evolution of the animal kingdom. The model does not tell us about individual families making individual choices on how to safely feed their children, especially not for humans in the modern world. Our hypothesis fills a gap in evolutionary theory and is concerned with selection pressures on mammals at population level and over very long periods of time spanning multiple generations.”

T-Mobile is buying U.S. Cellular’s wireless operations and certain spectrum assets in a deal valued at $4.4 billion, and further consolidating the industry.

T-Mobile would get more than 4 million new customers and control of U.S. Cellular’s wireless operations and about 30% of spectrum assets across several spectrum bands. T-Mobile will also enter into a new master license agreement on more than 2,000 towers and extend the lease term for the approximately 600 towers where T-Mobile is already a tenant.

T-Mobile CEO Mike Sievert said the deal will “create a better experience for all of our customers with more coverage and more capacity.”

It may also signal the start of more consolidation in an industry with fewer players than ever. “The writing is on the wall for the carriers and consolidation is now on the horizon and could speed up into 2025,” said Wedbush Securities analyst Dan Ives. “This is the first shot across the bow in the wireless world and we expect more deals over the next year.

T-Mobile is among the more active companies in telecommunications with regard to mergers and acquisitions. In 2020 T-Mobile completed the takeover of smaller rival Sprint. And in 2013 the Federal Communications Commission approved its merger with MetroPCS Communications Inc.

T-Mobile said Tuesday that U.S. Cellular customers will gain access to its 5G network, giving them better coverage and speed. The company said the deal will particularly benefit those that live in underserved rural areas of the country.

“In the face of rising competition and increasing capital intensity required to keep pace with the latest technologies, and following our careful and deliberate strategic review, we are confident that continuing to deliver on our mission requires a level of scale and investment that is best achieved by integrating our wireless operations with those of T-Mobile,” U.S. Cellular Chair LeRoy Carlson Jr. said in a statement.

T-Mobile said that U.S. Cellular customers will be able to remain on their current plans or switch to an unlimited T-Mobile plan of their choice. They will not incur switching costs if a plan change is made.

That is a mixed bag for consumers, said Ives at Wedbush.

“The U.S. consumer has less choice but there is more competition and this could drive prices lower,” Ives said.

The transaction includes a combination of cash and up to about $2 billion of assumed debt. Up to $100 million of the cash component is contingent on hitting certain financial and operational metrics between the deal’s signing and closing.

U.S. Cellular will keep about 70% of its spectrum portfolio across several spectrum bands.

The deal has been unanimously approved by the boards of United States Cellular Corp. and Telephone and Data Systems Inc, which is a majority shareholder of U.S. Cellular. It is expected to close in mid-2025.

U.S. Cellular’s stock jumped more than 2% in morning trading on Tuesday.

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Today’s intelligent robots can accurately recognize many objects through vision and touch. Tactile information, obtained through sensors, along with machine learning algorithms, enables robots to identify objects previously handled.

However, sensing is often confused when presented with objects similar in size and shape, or objects unknown to the robot. Other factors restrictive to robot perception include background noise and the same type of object with different shapes and sizes.

In Applied Physics Reviews, researchers from Tsinghua University worked to break through the difficulties of robotic recognition of various common, yet complex, items.

Humans possess many different types of touch sensing, one of which is thermal feeling. This allows us to sense the wind blowing, perceive hot and cold, and discriminate between matter types, such as wood and metal, because of the different cooling sensations produced.

The researchers aimed to mimic this ability by designing a robotic tactile sensing method that incorporated thermal sensations for more robust and accurate object detection.

“We propose utilizing spatiotemporal tactile sensing during hand grasping to extend the robotic function and ability to simultaneously perceive multi-attributes of the grasped object, including thermal conductivity, thermal diffusivity, surface roughness, contact pressure, and temperature,” said author Rong Zhu.

The team created a layered sensor with material detection at the surface and pressure sensitivity at the bottom, with a porous middle layer sensitive to thermal changes. They paired this sensor with an efficient cascade classification algorithm that rules out object types in order, from easy to hard, starting with simple categories like empty cartons before moving on to orange peels or scraps of cloth.

To test the capabilities of their method, the team created an intelligent robot tactile system to sort garbage. The robot picked up a range of common trash items, including empty cartons, bread scraps, plastic bags, plastic bottles, napkins, sponges, orange peels, and expired drugs. It sorted the trash into separate containers for recyclables, food scraps, hazardous waste, and other waste.

Their system achieved a classification accuracy of 98.85% in recognizing diverse garbage objects not encountered previously. This successful garbage sorting behavior could greatly reduce human labor in real-life scenarios and provide a broad applicability for smart life technologies.

Future research in this area will focus on enhancing robotic embodied intelligence and autonomous implementation.

“In addition, by combining this sensor with brain-computer interface technology, tactile information collected by the sensor could be converted into neural signals acceptable to the human brain, re-empowering tactile perception capabilities for people with hand disabilities,” said Zhu.