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‘Stealth’ material hides hot objects from infrared eyes  external link

A newly developed stealth sheet can hide hot objects like human bodies or military vehicles from infrared cameras Photo by Hongrui Jiang

Infrared cameras are the heat-sensing eyes that help drones find their targets even in the dead of night or through heavy fog.

Hiding from such detectors could become much easier, thanks to a new cloaking material that renders objects — and people — practically invisible.

“What we have shown is an ultrathin stealth ‘sheet.’ Right now, what people have is much heavier metal armor or thermal blankets,” says Hongrui Jiang, professor of electrical and computer engineering at the University of Wisconsin–Madison.

Hongrui Jiang UW-Madison College of Engineering

Warm objects like human bodies or tank engines emit heat as infrared light. The new stealth sheet, described this week in the research journal Advanced Engineering Materials, offers substantial improvements over other heat-masking technologies.

“It’s a matter of the weight, the cost and ease of use,” says Jiang.

Less than one millimeter thick, the sheet absorbs approximately 94 percent of the infrared light it encounters. Trapping so much light means that warm objects beneath the cloaking material become almost completely invisible to infrared detectors.

Importantly, the stealth material can strongly absorb light in the so-called mid- and long-wavelength infrared range, the type of light emitted by objects at approximately human body temperature.

By incorporating electronic heating elements into the stealth sheet, the researchers have also created a high-tech disguise for tricking infrared cameras.

“You can intentionally deceive an infrared detector by presenting a false heat signature,” says Jiang. “It could conceal a tank by presenting what looks like a simple highway guardrail.”

To trap infrared light, Jiang and colleagues turned to a unique material called black silicon, which is commonly incorporated into solar cells. Black silicon absorbs light because it consists of millions of microscopic needles (called nanowires) all pointing upward like a densely-packed forest. Incoming light reflects back and forth between the vertical spires, bouncing around within the material instead of escaping.

Although black silicon has long been known to absorb visible light, Jiang and colleagues were the first to see the material’s potential for trapping infrared. They boosted its absorptive properties by tweaking the method through which they created their material.

“We didn’t completely reinvent the whole process, but we did extend the process to much taller nanowires,” says Jiang, who developed the material in National Science Foundation-supported facilities at UW–Madison.

They make those nanowires by using tiny particles of silver to help etch down into a thin layer of solid silicon, which results in a thicket of tall needles. Both the nanowires and the silver particles contribute to absorbing infrared light.

The researchers’ black silicon also has a flexible backing interspersed with small air channels. Those air channels prevent the stealth sheet from heating up too quickly as it absorbs infrared light.

Jiang and colleagues are working to scale up their prototype for real-world applications with assistance from UW–Madison’s Discovery to Product program. They received a U.S. patent in the fall for the material’s use in stealth. The Wisconsin Alumni Research Foundation supported the research through its Robert Draper Technology Innovation Fund, and is actively pursuing two additional patent applications.

A modified version of a stealth sheet can disguise the appearance of objects on infrared cameras. Here, a ball appears as a bar to the infrared detector. Photo by Hongrui Jiang

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Best ever at splitting light, new material could improve LEDs, solar cells, optical sensors  external link

Place a chunk of the clear mineral Iceland spar on top of an image and suddenly you’ll see double, thanks to a phenomenon called double refraction — a result of a quality of the crystal material called optical anisotropy. Beyond just a nifty trick, materials with optical anisotropy are vital for a variety of devices such as lasers, liquid-crystal displays, lens filters and microscopes.

Photo: Double-image of Bucky Badger picture shown through calciite

Calcite splits light due to a property called birefringence, causing a double image. Photo: Sam Million-Weaver

Now, a team of scientists and engineers led by the University of Wisconsin–Madison and University of Southern California have created a crystal that has a higher degree of optical anisotropy than all other solid substances on earth — especially for infrared light. They described the new material in a paper published Monday in the journal Nature Photonics.

“The optical anisotropy is enormous, making the material promising for a range of optics applications,” says Mikhail Kats, a professor of electrical and computer engineering at UW–Madison and one of the senior authors on the paper.

One especially promising use for the new crystal could be imaging and other types of remote sensing using the mid-infrared transparency window, an especially important range of wavelengths that penetrate Earth’s atmosphere with little distortion.

“This class of materials and this approach has a lot of potential,” says Jayakanth Ravichandran, a professor of chemical engineering and materials science and electrical engineering-electrophysics at USC, and a senior author of the study. “We designed the material, made it, and saw a huge effect.”

The new crystal has roughly 50 to 100 times greater optical birefringence — a metric of anisotropy — for mid-infrared light than has ever been measured before. That spectacular light-splitting ability comes from a unique molecular structure consisting of long chains of atoms arranged in parallel rows.

Image: Artist’s colorful rendering of new material

Artist’s rendering of a new material that splits light more dramatically than any other substance on Earth. Image: Talia Spencer

Using advanced computational methods, the researchers carefully selected rows of atoms, precisely grew them in the lab, and meticulously studied them.

Optical anisotropy is the tendency of some materials to alter light’s progress through them differently depending on how the beams are traveling. Light slows down by predictably different amounts when it passes through different materials, which is why beams bend when they transition between the air and substances like water or glass.

That light bending is called refraction, and it’s part of what gives diamonds their sparkle.

Photo: Calcite turned green by laser beam

A laser beam passing through the mineral calcite splits due to a property called birefringence. Researchers made a new material that has a higher birefringence than any substance on Earth. Photo: Sam Million-Weaver

Light waves in the same beam traveling through a material with optical anisotropy will slow down more or less depending on polarization, a measure of the direction in which waves vibrate.

Human eyes cannot see polarization on their own, but the ability to alter the vibrational orientation of light is essential for LCD screens, 3D movies, lasers and lens filters. Most devices that change light’s polarization rely on materials with optical anisotropy.

The new material might also be useful in energy-harvesting photovoltaic cells or light-emitting diodes. In the future, the researchers plan to explore other properties of the new material as they also work to develop strategies to synthesize it in large quantities.

The project was a team effort involving researchers at multiple institutions with varied expertise.

Photo: Kats and Jad Salmon standing in front of a whiteboard with graphs and equations

Study authors Mikhail Kats (right) and Jad Salman of UW–Madison, with a sample of the light-splitting mineral calcite. Photo: Sam Million-Weaver

“This is a big success for collaborative science,” says Kats, who led the optical measurements, while Ravichandran and USC electrical engineering Professor Han Wang synthesized the material. “The wide array of knowledge and capabilities across our team enabled this breakthrough.”

The scientists are filing a patent on the material through USC and the Wisconsin Alumni Research Foundation at UW–Madison. Other collaborators included scientists at the University of Missouri and the Air Force Research Laboratory at Wright-Patterson Air Force Base.

This research was supported by grants from the U.S. Air Force Office of Scientific Research (FA9550-16-1-0335 and FA9550-15RXCOR198), the Link Foundation Energy Fellowship, the Office of Naval Research (N00014-16-1-2556), the Army Research Office (W911NF-16-1-0435), the National Science Foundation (ECCS- 1653870) and the Department of Energy (DE-SC0001299, DE-FG02-09ER46577 and DE-FG02–07ER46376).

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UW-Madison partners with Madison high schools to promote college and career readiness  external link

Professors Maureen Euhardy and Lisa Steinkamp discuss opportunities in the Department of Physical Therapy during a tour offered to MMSD high school students. Emily Hamer

In a partnership with the Madison Metropolitan School District, UW-Madison is making strides in showing high school students the opportunities they have for post-secondary education.

The university has joined in MMSD’s Personalized Pathways initiative — a program launched last fall for ninth grade students from Madison East, Madison West, La Follette and Memorial high schools — which groups students into smaller learning communities focused on curriculum and careers in the health services field.

UW-Madison recently offered campus tours centered on health services to more than 400 high school students. The tours explored the many academic and professional opportunities within the pathway and showed students that college is an attainable goal, says Leslie Orrantia, the university’s director of community relations.

“By demonstrating that some of the university’s values link back to the students’ curriculum and their day-to-day experiences, we can complement that relationship and build a greater perceived access to institutions like UW-Madison and to higher education in general,” she says.

The tours also served as a way to develop college readiness in high schoolers, something Todd Reck, manager for student experience in the university’s Division of Enrollment Management, says may help to further close existing socioeconomic achievement gaps.

“It’s part of our mission as a university to be a good member of our local community,” he says. “It’s very much in the university’s interest to have a strong Madison community and with that comes an even stronger school district.”

Graduate students in the Department of Physical Therapy talk of their college experience and answer questions from high school students. Emily Hamer

During the visits, the Office of Admissions and Office of Student Financial Aid presented information on ways to prepare and pay for college, as well as the college application and admissions process. Participants were also introduced to student life and campus facilities by student tour guides, offering the high schoolers an opportunity to ask questions of actual college students.

In keeping with the health services theme, groups learned about various careers and research opportunities in the field. Among the six buildings they visited around campus were the School of Nursing, the Primate Research Center and the Department of Physical Therapy.

This ultimately played a role in motivating the high schoolers to “explore where they can take a health science career in the future,” Reck says.

According to Orrantia, the partnership benefits both the school district and the university. She says reaching out to local communities of color within MMSD ensures that UW-Madison continues to grow and diversify its student population.

“We really value this opportunity and support to the district,” Orrantia said. “It is mutually beneficial, and the collaboration has existed at all levels.”

The university’s Personalized Pathway partnership with MMSD will continue throughout the summer as well. Starting next week, local high schoolers will participate in paid health services internships at UW-Madison.

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Heavier rains and manure mean more algae blooms  external link

An algae bloom began to spread across Lake Mendota on June 6, 2018, prompting beach closures in affected areas. It led to foul-smelling, discolored water in places like Willow Creek on the UW–Madison campus, pictured here, spreading into the delta where the creek drains into Lake Mendota. Algae blooms can be prompted by phosphorus and other urban contributors to local waterways. Photo by Carrie Eaton, UW-Madison

On June 6, 2018, the Center for Limnology reported that a toxic algae bloom had begun to spread across Lake Mendota. It quickly led to the closure of beaches around Madison’s largest lake.

It also coincided with the launch of a new, four-year effort by Dane County, called Suck the Muck, designed to literally suck a century’s-worth of phosphorus from 33-miles of streams that feed the county’s lakes.

Phosphorus, a nutrient found in the manure applied to agricultural fields, makes its way to Wisconsin waters (and waterways elsewhere) in runoff following rain storms. When the weather is warm, it can lead to the foul-smelling water and toxic algae blooms that plague lakes like Mendota, which is situated in an agricultural landscape.

A new study shows that an increase in high-intensity rain storms interacts with manure applied to agricultural fields to make exacerbate phosphorus runoff, which can lead to toxic algae blooms. Photo by Carrie Eaton, UW-Madison

This runoff may be getting worse, according to a recent study from researchers with the Water Sustainability and Climate Project at the University of Wisconsin–Madison. With a changing climate, the frequency of high-intensity rain events is on the rise. These storms bring heavy rains over a short period of time and exacerbate phosphorus runoff from manure-covered agricultural fields, more so than scientists expected.

“Both things are bad for water quality – too much manure is bad and too many intense storms are bad, too,” says lead author of the study in Environmental Research Letters, Melissa Motew. “This is a story about how one problem really compounds another problem.”

Indeed, the Lake Mendota algal bloom came on the heels of the second-wettest May in Madison’s recorded history, and its eighth warmest. The National Weather Service reported that May 2018 was the wettest on record for the contiguous United States.

But Motew didn’t start out asking how heavy storms and manure interact synergistically to affect water quality. It was while studying legacy phosphorus in soils ­– the accumulation of the nutrient over time – that she and the research team noticed something interesting in the data.

“We knew that heavy rain transports a lot of phosphorus off of a field and in 2014, (co-author Stephen Carpenter, emeritus professor and director of CFL) found that a relatively small number of rain events each year were delivering the majority of phosphorus to the lakes,” she explains. “We happened to notice that it seemed like when we had periods of heavy rainfall we were seeing worse water quality than we expected. It prompted us to set up this study.”

Climate change is bringing more intense rainfall across the U.S., particularly in the Midwest and Northeast. The 2014 study from Carpenter and colleagues showed that 74 percent of the phosphorus load in Lake Mendota is now delivered across just 29 days each year, and a 2016 study from scientists at Marylhurst University in Oregon and UW–Madison showed that annual precipitation in the Yahara watershed, which includes Lake Mendota, increased by 2.1 mm each year between 1930 and 2010.

This amounts to an increase of about seven inches of additional rain today, Motew explains. That same study also showed that while the frequency of large storm events in the region averaged 9.5 events per decade between 1930 and 1990, between 1991 and 2010, the number of large storm events nearly doubled, reaching 18 events per decade.

Using simulation models, Motew and the study team asked how more extreme rain events might interact with manure-and-fertilizer phosphorus supply on croplands to affect runoff at the level of an individual lake and the streams that feed it. That is, what happens when a given amount of rain falls on a field over the course of two hours instead of 24 hours?

“The model lets us scale up and make interesting observations from the scale of one field to the entire watershed,” she says. “Models let us home in and study the process of how phosphorus moves in great detail.”

Using two 60-year climate scenarios, one which assumed daily precipitation, maximum and minimum temperatures, wind speeds, relative humidity and solar radiation similar to current mean annual values in Madison, and another assuming more extreme rain events, Motew’s model explored what happens to phosphorus concentrations in Lake Mendota and its tributary streams under low- and high-intensity precipitation conditions.

“This result also has wide-reaching implications because the synergistic relationship will likely be present in many agricultural watersheds around the world, where livestock and surface water co-exist.”

Christopher Kucharik

It took into account the real-life practices of farmers in the watershed – including their typical fertilizer and manure applications and tillage practices, the amount of phosphorus already stored in the surface layers of the soil, and the composition of the land around Lake Mendota. More than half of the land surrounding it is agricultural.

Motew found that dissolved phosphorus – the kind found in manure, as compared to other fertilizers and that found in soil – combined synergistically with heavy rain events to increase the amount of phosphorus running off into Lake Mendota and its streams.

“This puts us at even greater risk of worsening water quality,” says Christopher Kucharik, study co-author and Motew’s former graduate advisor. “This result also has wide-reaching implications because the synergistic relationship will likely be present in many agricultural watersheds around the world, where livestock and surface water co-exist.”

Phosphorus is a critical nutrient for living organisms like crops. But what it does on land, it also does in water: encourages growth of organisms like plants and algae. When they die, these organisms fall to the bottom of an affected waterway, decomposing and consuming oxygen. This kills wildlife and encourages the growth of cyanobacteria, the organism behind toxic algae blooms. In some parts of the country, it can lead to dead zones, like in the Gulf of Mexico.

Farmers in Dane County and elsewhere are already applying less manure and doing so more precisely, Motew says, and she is hopeful these strategies will help to reduce phosphorus runoff from their croplands.

Motew, who is now a research fellow at The Nature Conservancy, also thinks farmers should be a part of continuing efforts to improve water quality. “We need to partner more with farmers so we can not only improve our own research by using better data, but so we can work together and build on their ideas, too.” she says. “They know the problems up-close-and-personal and can provide insights we haven’t considered. We as scientists can help explore where those insights may lead.”

Motew adds: “Farmers are key to solving the problem, even though they are frequently blamed. We all need to take responsibility for our food system and find ways to support farmers in better manure management.”

The study was supported by the National Science Foundation (grant numbers DEB-1038759 and DEB-1440297).

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Study of inflammation’s link to diseases wins NIH grant  external link

In the coming decades, David Beebe expects the public to become more and more aware of the links between chronic inflammation and a whole host of ailments.

“It’s likely implicated in almost every disease,” says Beebe, the John D. MacArthur Professor and Claude Bernard Professor of biomedical engineering at the University of Wisconsin–Madison, rattling off a list of illnesses that includes cancer, cardiovascular conditions and autoimmune diseases. “But it’s been really difficult to study and we don’t know a lot about it.”

Beebe and longtime collaborator Anna Huttenlocher, a professor of medical microbiology and immunology and pediatrics at UW–Madison, are out to change that by studying inflammation on a fundamental level.

Photo: David Beebe

David Beebe

Photo: Anna Huttenlocher

Anna Huttenlocher

They’ll use a recently awarded five-year, $3.7 million grant from the National Institutes of Health to examine the onset and resolution of inflammation — work that could point the way to new targeted drug therapies. The grant is funded by the National Institute of Allergy and Infectious Diseases.

The researchers will analyze the movement, behavior and communication of neutrophils, the most common type of white blood cell in our bodies, using models of microfluidics — the movement of liquids through tiny spaces, an area in which Beebe is a national leader. Neutrophils are part of the innate immune system, the portion of our body’s overall defense scheme that responds immediately and uniformly to threats. However, continual neutrophil inflammation can damage tissue and play a role in the chronic inflammation associated with a variety of diseases.

“If we understand this process, then we can say, ‘Well, if we can tweak this part of the process, we could potentially stop inflammation,’” says Beebe, who notes that the innate immune system has been understudied compared to the adaptive immune system, which crafts cells specifically tailored to each type of invader.

Photo: Zebrafish swimming

The new work has roots in Huttenlocher’s observation in a zebrafish in which neutrophils moved from a blood vessel to a wound before returning to the vessel. Photo: goodfreephotos.com

The new work has roots in a 2006 discovery in Huttenlocher’s lab: an observation in a zebrafish in which neutrophils moved from a blood vessel to a wound before returning to the vessel — the first such demonstration of so-called “reverse migration.” Previous thinking held that neutrophils responded to a problem and then either died or were consumed by macrophages, another kind of white blood cell.

“Now we know this is a real phenomenon, but we don’t know much about the detailed biology of why neutrophils will return to the blood vessel,” says Beebe, who along with Huttenlocher is a University of Wisconsin Carbone Cancer Center researcher. “This grant is all about developing a model on a benchtop, so that we can study that biology and actually replicate that phenomenon. And then by doing that in our little microsystem, we can watch it under a microscope, we can genetically modify things, we can understand exactly what is causing it.”

The two researchers will also attempt to model an occurrence of vasculitis, a chronic inflammation of blood vessels caused by a specific gene mutation in a subset of Huttenlocher’s clinical patients. By using induced pluripotent stem cells and the gene editing tool CRISPR to replicate the gene mutation, they hope to provide an early glimpse at an approach that could allow researchers to create models tailored to particular groups of patients. Such models could inform therapeutic decisions.

By better understanding the process behind inflammation, Beebe says, the researchers will be able to identify pathways to potentially target with drugs.

“This is a very basic biology grant, but it really does have direct implications potentially to a lot of different diseases,” he says.

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Searching the sea, and bacterial battles, for new antibiotics  external link

Alexander Fleming’s discovery of penicillin — the world’s first natural antibiotic — is famously told as a story of serendipity: a petri dish growing bacteria was contaminated by mold, which secreted a substance to keep bacteria at bay. The lesson learned was that science can take advantage of chance encounters to change the world.

But perhaps the scientists that followed in Fleming’s footsteps should have paid closer attention to a core aspect of his discovery: that it hinged on the relationship between microscopic competitors fighting for space.

Photo: Tim Bugni

Tim Bugni, a chemist by training, is a professor of pharmacy at UW–Madison. Photo: Sally Griffith-Oh

University of Wisconsin–Madison researchers are collaborating across colleges and departments to relearn the lessons of penicillin. They are stepping beyond an era when microbes were grown alone in search of new antibiotics by growing different species together. Their goal is to stimulate natural defenses against old foes, like what took place when the penicillium mold attacked staphylococcus bacteria in Fleming’s lab cultures. These coculturing techniques aim to recreate aspects of real ecosystems to spur dormant and hidden antibiotic capacities into action.

After years improving this relatively new method, scientists at the UW–Madison School of Pharmacy and the College of Agricultural and Life Sciences discovered the new antibiotic keyicin, a demonstration of the technique’s effectiveness. Researchers say this discovery would not have been possible without a cross-college collaboration going back nearly a decade.

Photo: Lingjun Li

Professor of Pharmacy Lingjun Li also contributed to the cross-disciplinary collaboration. Photo: Sally Griffith-Oh

The microbes that give us most of our antibiotics never grow alone in nature. Yet they have that luxury in the lab, where scientists grow bacteria or fungi in isolation to study them one at a time. Many life-saving antibiotics were discovered under these conditions. But over time those discoveries waned, while pathogens began developing resistance to existing drugs.

“The well had run dry,” says Tim Bugni, a chemist by training and a professor of pharmacy at UW–Madison who was the senior author of the paper announcing keyicin, published in 2017. “In the ’90s, most pharmaceutical companies abandoned this area of research. Starting in 2000, genomics really started taking off.”

The genomic era revealed a tantalizing opportunity: DNA sequencing showed that many bacteria had troves of genes for making novel antibiotics. They were just never activated. Even the most creative laboratory conditions could not induce the microbes to tap into this arsenal of new chemicals.

Photo: Steven Chu and Cameron Currie in lab

Cameron Currie, right, with U.S. Energy Secretary Steven Chu in the Microbial Sciences Building in 2012. Photo: Jeff Miller

When Bugni arrived at UW–Madison in 2009, he soon began working with Cameron Currie, a professor of bacteriology. The two shared an interest in partnerships between microbes and animals and in antibiotic research.

“A lot of these silent genetic capacities for producing antimicrobial compounds are linked to the ecological role they play,” says Currie, a co-author of the keyicin paper. Professor of Pharmacy Lingjun Li also contributed to the work, which was led by Bugni’s former graduate student Navid Adnani. Collaborators at the University of Minnesota, Yumanity Therapeutics and Bruker Daltonics also contributed.

“Given that producing antibiotics is energetically costly to bacteria, if they are using them in an ecological framework, to inhibit a pathogen or competitor, it makes sense from an evolutionary perspective to only do so when they get a signal from the target organism, instead of continually cranking it out,” says Currie.

In theory, a competing microbe provides that missing signal. In response to the threat, bacteria turn on their once-silent genes, pumping out a previously uncharacterized antibiotic. The researchers discovered keyicin when the bacterium Micromonospora was challenged with Rhodococcus. Over time, the keyicin produced by Micromonospora helped it take over the culture.

Photo: Navid Adnani

The work was led by Bugni’s former graduate student Navid Adnani.

Both strains of bacteria came from the ocean, where they are associated with invertebrates. A sizable portion of existing antibiotics were discovered in bacteria that live in the soil. But continued work with these terrestrial bacteria has discovered the same drugs over and over again. Bugni, who specializes in marine microbes, says tapping into this relatively uncharted ecosystem gives scientists a better chance of avoiding this “rediscovery problem,” which plagues antibiotic research.

“There’s a lot of unexplored bacterial diversity in the marine environment,” Bugni says.

The coculturing work is funded by a Center of Excellence for Translational Research grant from the National Institutes of Health. David Andes, a professor and chief of infectious diseases at the University of Wisconsin School of Medicine and Public Health, leads the grant, which Currie and Bugni are members of. While Bugni focuses on marine bacteria, Currie specializes in microbes associated with insects on land.

The team is assessing keyicin for its therapeutic potential in animals. (Most new antibiotics face considerable hurdles to being used in humans, but only more research will tell.) In the meantime, researchers say the proof of concept provided by the discovery of keyicin suggests that coculturing will continue to provide more new antibiotic candidates.

This approach requires evolutionary, biological, chemical and medical expertise directed at an increasingly complex problem.

“This kind of interdisciplinary work is absolutely critical to be successful in this realm,” says Currie.

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Hurricanes are slowing down, and that’s bad news  external link

Photo: Aerial view of buildings partially underwater

In 2017, Hurricane Harvey drenched Houston and nearby areas with as much as 50 inches of rain in one day, leaving some areas under several feet of water. Photo: U.S. Air National Guard

Some hurricanes are moving more slowly, spending increased time over land and leading to catastrophic local rainfall and flooding, according to a new study published Wednesday (June 6) in the journal Nature.

While hurricanes batter coastal regions with destructive wind speeds, study author James Kossin says the speed at which hurricanes track along their paths — their translational speed — can also play a role in the damage and devastation they cause. Their movement influences how much rain falls in a given area.

This is especially true as global temperatures increase.

“Just a 10 percent slowdown in hurricane translational speed can double the increase in rainfall totals caused by 1 degree Celsius of global warming,” says Kossin, a researcher at the National Oceanic and Atmospheric Administration’s (NOAA) Center for Weather and Climate. He is based at the University of Wisconsin–Madison.

Photo: Jim Kossin on rooftop next to satellite dish

Based at UW–Madison, Jim Kossin is a researcher at the National Oceanic and Atmospheric Administration’s (NOAA) Center for Weather and Climate. Photo: Greg Anderson

The study compared 68 years (1949–2016) of worldwide hurricane track and intensity data, known as best-track data, from NOAA to identify changes in translational speeds. It found that, worldwide, hurricane translational speeds have averaged a 10 percent slowdown in that time.

One recent storm highlights the potential consequences of this slowing trend. In 2017, Hurricane Harvey stalled over eastern Texas rather than dissipating over land, as hurricanes tend to do. It drenched Houston and nearby areas with as much as 50 inches of rain over several days, shattering historic records and leaving some areas under several feet of water.

How much hurricanes have slowed depends on where they occur, Kossin found. “There is regional variation in the slowdown rates when looking at the 10 percent global average across the same time frame,” he says.

The most significant slowdown, 20 percent, occurred in the Western North Pacific Region, an area that includes Southeast Asia. Nearby, in the Australian Region, Kossin identified a reduction of 15 percent. In the North Atlantic Region, which includes the U.S., Kossin found a 6 percent slowdown in the speeds at which hurricanes move.

When further isolating the analysis to hurricane speeds over land, where their impact is greatest, Kossin found that slowdown rates can be even greater. Hurricanes over land in the North Atlantic have slowed by as much as 20 percent, and those in the Western North Pacific as much as 30 percent.

Photo: Satellite view of Hurricane Harvey

Hurricane Harvey stalled over eastern Texas rather than dissipating over land, as hurricanes tend to do. Photo: NASA/NOAA

Kossin attributes this, in part, to the effects of climate change, amplified by human activity. Hurricanes move from place to place based on the strength of environmental steering winds that push them along. But as the Earth’s atmosphere warms, these winds may weaken, particularly in places like the tropics, where hurricanes frequently occur, leading to slower-moving storms.

Additionally, a warmer atmosphere can hold more water vapor, potentially increasing the amount of rain a hurricane can deliver to an area.

The study complements others that demonstrate climate change is affecting hurricane behavior.

For instance, in 2014, Kossin showed that hurricanes are reaching their maximum intensities further from the tropics, shifting toward the poles in both the Northern and Southern Hemispheres. These shifts can deliver hurricanes to areas — including some heavily populated coastal regions — that have not historically dealt with direct hits from storms and the devastating losses of life and property that can result.

Another study, published in April by researchers at the National Center for Atmospheric Research, used a modeling approach to look at what would happen to hurricanes under future climate projections. Using real hurricane data from 2000–2013, the researchers found future hurricanes will experience a 9 percent slowdown, higher wind speeds, and produce 24 percent more rainfall.

“The rainfalls associated with the ‘stall’ of 2017’s Hurricane Harvey in the Houston, Texas, area provided a dramatic example of the relationship between regional rainfall amounts and hurricane translation speeds,” says Kossin. “In addition to other factors affecting hurricanes, like intensification and poleward migration, these slowdowns are likely to make future storms more dangerous and costly.”

The study was supported by NOAA’s National Centers for Environmental Information.

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UW physicists, CERN announce discovery of Higgs boson interactions  external link

Photo: Worker seen through a semiconductor barrell

A researcher works on a semiconductor tracker barrel for the ATLAS experiment at the Large Hadron Collider. © CERN

The international particle accelerator collaboration CERN announced Monday, June 4, that two experiments at the Large Hadron Collider discovered a link between the two heaviest known particles: the top quark and the Higgs boson.

University of Wisconsin–Madison physicists are members of the CMS and ATLAS experiments at CERN, which jointly discovered the Higgs boson in 2012. The same two experiments have now seen simultaneous production of both the Higgs boson and the top quark during a rare subatomic process.

This is the first time scientists have measured the Higgs boson’s direct interaction with top quarks. Studying these particles gives clues about the nature of matter and mass in the universe.

Photo: Wesley Smith

Wesley Smith

Photo: Sau Lan Wu

Sau Lan Wu

“The members of the CMS collaboration are very pleased to be publishing the first observation of direct coupling of the Higgs boson to the top quark and that the ATLAS experiment also observes this,” says Wesley Smith, a professor of physics and the leader of the Particle Physics Group and the CMS program at UW–Madison.

The CMS findings were published June 4 in Physical Review Letters. ATLAS submitted its work for publication the same day.

“It is exciting to have our research group contribute new analysis techniques employing advanced machine learning and statistics to help produce this very significant result from the ATLAS collaboration,” says UW–Madison Professor of Physics Sau Lan Wu, who leads the Wisconsin ATLAS group.

Studying these particles gives clues about the nature of matter and mass in the universe.

Fundamental particles gain mass through their interaction with the Higgs field, so it would make sense that the top quark — the most massive particle ever discovered — would have a strong coupling with the Higgs boson. But scientists say they need to test every aspect of the theory in order to fully verify it.

Before its discovery, theorists had a good picture of how the Higgs boson was supposed to behave, according to the Standard Model of particle physics. Now that physicists can nimbly produce and study Higgs bosons, the next step is to scrutinize these predictions and see if they hold water. A big question has been whether the Higgs boson can interact with quarks and, if so, what this relationship might look like.

Photo: Pixel detector

A pixel detector used in the CMS experiment at the Large Hadron Collider. © CERN

Even though scientists suspected that the Higgs boson interacts more strongly with the massive top quark than any other, all evidence until recently has been below the threshold required to claim a discovery. The new results show definitively that the Higgs boson communicates with the top quark as predicted and opens up a new door to explore these interactions further.

The interaction between the Higgs boson and the top quark was confirmed by identifying the two particles coming out of the same collision between two protons. It is a rare event — occurring in only one percent of certain particle collisions — making it challenging to track, says Wu.

UW–Madison researchers contributed extensively to data analysis as well as equipment design and computational resources. The CMS collaboration is made up of over 4,000 scientists and ATLAS comprises some 3,000.

Further studies will continue to explore the behavior of the Higgs boson and how it fits into the universal mosaic of matter.

This work was funded in part by the National Science Foundation and the Department of Energy.

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Two professors receive Shaw Scientist Awards to support innovative research  external link

University of Wisconsin–Madison biochemistry assistant professor Philip Romero and neuroscience assistant professor Ari Rosenberg are the recipients of 2018 Shaw Scientist Awards from the Greater Milwaukee Foundation. The awards come with $200,000 in seed funding to support innovative research approaches and the career development of young investigators.

Photo: Philip Romero

Philip Romero

Photo: Ari Rosenberg

Ari Rosenberg

Romero’s work uses new technologies to understand how proteins work and how to design new ones. Using computational methods, he is able to analyze large amounts of data that help him investigate the relationships between protein sequence, structure and function. This allows him to pull out sequences that lead to useful properties and design new proteins with desired functions.

His research has many implications because the proteins can be engineered to have specific functions, such as in bioenergy, chemical production and human health. Projects are investigating how to help convert biomass to fuel and develop cancer therapeutics. Along with these applications, the group also focuses on developing new protein engineering methods.

“The Shaw Award will enable us to pursue new high-risk projects that wouldn’t be supported by the standard funding agencies,” Romero says. “We’re excited to think longer term about where our field is headed, and how we can make a large impact on engineering biological systems.”

Romero joined the department in July 2016. He earned his Ph.D. at the California Institute of Technology. At UW–Madison, he is also affiliated with the Department of Chemical and Biological Engineering.

Romero joins a decades-long line of Department of Biochemistry faculty members in receiving the award. In 2017, assistant professor Ophelia Venturelli received a Shaw Award and the year before that, so did assistant professor Vatsan Raman, with many more before them.

“The Shaw Award will enable us to pursue new high-risk projects that wouldn’t be supported by the standard funding agencies.”

Philip Romero

Rosenberg’s research recognizes that despite the noisy and ambiguous input received by the body’s eyes, ears and other sensory organs, people perceive the world accurately and precisely. Unlocking how the brain performs this transformation is a path to understanding neurological and neuro-developmental conditions, such as traumatic brain injury and autism.

Using multifaceted experimental and computational approaches, Rosenberg’s lab is quantifying the neural basis of robust perception to ultimately guide development of individualized treatments for brain disorders. It’s an approach whose potential is being realized because of the Shaw Scientist Award.

“Research funding today tends to favor studies that have a high chance of finding an unsurprising result, and discourages more speculative studies that might yield big gains,” Rosenberg says. “For a young scientist like myself, the Shaw Scientist Award eliminates such barriers, making it possible to pursue unexplored research avenues that might not otherwise see the light of day.”

Rosenberg joined the faculty at UW–Madison in 2015 and earned his Ph.D. in computational neuroscience from the University of Chicago. He previously was awarded an Alfred P. Sloan Research Fellowship in neuroscience. The highly sought-after award honors early-career scientists whose achievements and potential identify them as “rising stars.”

“For a young scientist like myself,” the award makes it “possible to pursue unexplored research avenues that might not otherwise see the light of day.”

Ari Rosenberg

The Shaw Scientist Awards program began in 1982 thanks to a $4.3 million bequest from Dorothy Shaw, widow of James Shaw, a prominent Milwaukee attorney. In addition to $2 million in special grants, the Shaws’ fund has awarded about $14 million in grants to 73 scientists from UW–Madison and UW–Milwaukee. An advisory panel including scientists representing major U.S. research institutions recommends the winners.

Founded more than a century ago, the Greater Milwaukee Foundation is the region’s largest community foundation and was among the first established in the world.

“Dorothy Shaw, whose generosity made this program possible, has left a tremendous legacy, not only by accelerating the work of stellar young researchers, but through biomedical advances — those discovered as well as those still to come — that her support has seeded,” says Ellen Gilligan, president and CEO of the Greater Milwaukee Foundation. “I congratulate this year’s recipients on their innovation in pursuit of knowledge.”


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Thank the moon for Earth’s lengthening day  external link

For anyone who has ever wished there were more hours in the day, geoscientists have some good news: Days on Earth are getting longer.

A new study that reconstructs the deep history of our planet’s relationship to the moon shows that 1.4 billion years ago, a day on Earth lasted just over 18 hours. This is at least in part because the moon was closer and changed the way the Earth spun around its axis.

“As the moon moves away, the Earth is like a spinning figure skater who slows down as they stretch their arms out,” explains Stephen Meyers, professor of geoscience at the University of Wisconsin–Madison and co-author of the study published June 4 in the Proceedings of the National Academy of Sciences.

It describes a tool, a statistical method, that links astronomical theory with geological observation (called astrochronology) to look back on Earth’s geologic past, reconstruct the history of the solar system and understand ancient climate change as captured in the rock record.

Photo: Composite of Earth and moon

During its flight to Jupiter in 1992, NASA’s Galileo spacecraft returned images of the Earth and Moon. Separate images were combined to generate this view. NASA/JPL/USGS

“One of our ambitions was to use astrochronology to tell time in the most distant past, to develop very ancient geological time scales,” Meyers says. “We want to be able to study rocks that are billions of years old in a way that is comparable to how we study modern geologic processes.”

Earth’s movement in space is influenced by the other astronomical bodies that exert force on it, like other planets and the moon. This helps determine variations in the Earth’s rotation around and wobble on its axis, and in the orbit the Earth traces around the sun.

These variations are collectively known as Milankovitch cycles and they determine where sunlight is distributed on Earth, which also means they determine Earth’s climate rhythms. Scientists like Meyers have observed this climate rhythm in the rock record, spanning hundreds of millions of years.

But going back further, on the scale of billions of years, has proved challenging because typical geologic means, like radioisotope dating, do not provide the precision needed to identify the cycles. It’s also complicated by lack of knowledge of the history of the moon, and by what is known as solar system chaos, a theory posed by Parisian astronomer Jacques Laskar in 1989.

The solar system has many moving parts, including the other planets orbiting the sun. Small, initial variations in these moving parts can propagate into big changes millions of years later; this is solar system chaos, and trying to account for it can be like trying to trace the butterfly effect in reverse.

“As the moon moves away, the Earth is like a spinning figure skater who slows down as they stretch their arms out.”

Stephen Meyers

Last year, Meyers and colleagues cracked the code on the chaotic solar system in a study of sediments from a 90 million-year-old rock formation that captured Earth’s climate cycles. Still, the further back in the rock record he and others have tried to go, the less reliable their conclusions.

For instance, the moon is currently moving away from the Earth at a rate of 3.82 centimeters per year. Using this present-day rate, scientists extrapolating back through time calculated that “beyond about 1.5 billion years ago, the moon would have been close enough that its gravitational interactions with the Earth would have ripped the moon apart,” Meyers explains. Yet, we know the moon is 4.5 billion years old.

Photo: Stephen Meyers

Geoscience Professor Stephen Meyers © Gigi Cohen

So, Meyers sought a way to better account for just what our planetary neighbors were doing billions of years ago in order to understand the effect they had on Earth and its Milankovitch cycles. This was the problem he brought with him to a talk he gave at Columbia University’s Lamont-Doherty Earth Observatory while on sabbatical in 2016.

In the audience that day was Alberto Malinverno, Lamont Research Professor at Columbia. “I was sitting there when I said to myself, ‘I think I know how to do it! Let’s get together!’” says Malinverno, the other study co-author. “It was exciting because, in a way, you dream of this all the time; I was a solution looking for a problem.”

The two teamed up to combine a statistical method that Meyers developed in 2015 to deal with uncertainty across time — called TimeOpt — with astronomical theory, geologic data and a sophisticated statistical approach called Bayesian inversion that allows the researchers to get a better handle on the uncertainty of a study system.

They then tested the approach, which they call TimeOptMCMC, on two stratigraphic rock layers: the 1.4 billion-year-old Xiamaling Formation from Northern China and a 55 million-year-old record from Walvis Ridge, in the southern Atlantic Ocean.

With the approach, they could reliably assess from layers of rock in the geologic record variations in the direction of the axis of rotation of Earth and the shape of its orbit both in more recent time and in deep time, while also addressing uncertainty. They were also able to determine the length of day and the distance between the Earth and the moon.

“In the future, we want to expand the work into different intervals of geologic time,” says Malinverno.

“It was exciting because, in a way, you dream of this all the time; I was a solution looking for a problem.”

Alberto Malinverno

The study complements two other recent studies that rely on the rock record and Milankovitch cycles to better understand Earth’s history and behavior.

A research team at Lamont-Doherty used a rock formation in Arizona to confirm the remarkable regularity of Earth’s orbital fluctuations from nearly circular to more elliptical on a 405,000 year cycle. And another team in New Zealand, in collaboration with Meyers, looked at how changes in Earth’s orbit and rotation on its axis have affected cycles of evolution and extinction of marine organisms called graptoloids, going back 450 million years.

“The geologic record is an astronomical observatory for the early solar system,” says Meyers. “We are looking at its pulsing rhythm, preserved in the rock and the history of life.”

The study was funded by the National Science Foundation (EAR-1151438).

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