The predictions were published today in The Lancet Infectious Diseases.

“There has been a resurgence of measles cases, among other vaccine preventable diseases, in the U.S. and other countries in recent years. Measles, in particular, poses a serious public health threat due to the highly contagious nature of the disease. It is therefore critical that we proactively identify areas most likely to experience outbreaks to strategically target for surveillance and control,” says Lauren Gardner, an associate professor in the Johns Hopkins Department of Civil Engineering and one of the study’s corresponding authors.

Cook County, Illinois, tops the list, followed by Los Angeles County, California, Miami-Dade County, Florida, Queens, New York, and King County, Washington. The researchers have made available an interactive web tool that maps counties and codes them by risk:

http://gisanddata.maps.arcgis.com/apps/opsdashboard/index.html#/33c650a3740f478e99e308da9e5908ec

As of late April, the U.S. has seen more than 700 cases of measles this year, the highest number in decades. Although measles was officially eliminated from the U.S. in 2000, the ongoing outbreak shows that the nation remains at risk.

The recent spike in cases, the researchers say, is due to reintroduction by international travelers from countries experiencing measles outbreaks, compounded by low-vaccination rates in certain localities that are fueled in part by an increasingly visible anti-vaccination movement.

“Anti-vaxxers are denying the best and very successful medical science we have and choosing instead to rely on fraudulent claims, such as a purported link to autism, that have been uniformly debunked by evidence and analysis over the last two decades,” says Sahotra Sarkar, professor of philosophy and integrative biology at the University of Texas at Austin and the study’s other corresponding author.

To identify the top 25 U.S. counties most likely to experience outbreaks in 2019, the research team performed a risk analysis that took the following county data into account: non-medical exemption rates, anonymous full-route passenger travel data from all international airports, population and size, and location of measles outbreaks globally.

The analysis correctly identified regions in Washington, Oregon, and New York that have already seen major measles outbreaks this year. Furthermore, the vast majority of counties that have reported measles cases as of April 2019 are included in team’s top 25 at-risk counties or lie adjacent to one of the top 25 counties. Additionally, the analysis specified the following countries that contribute most to measles risk in the U.S.: India, China, Mexico, Japan, Ukraine, Philippines, and Thailand.

“Our prediction is aligned with multiple counties that have experienced measles outbreaks this year. Critically, we recommend that public health officials and policymakers prioritize monitoring the counties we identify to be at high risk that have not yet reported cases, especially those that lie adjacent to counties with ongoing outbreaks and those that house large international airports,” says Gardner.

Sarkar adds that policymakers must focus on centers of vaccination resistance, as well as regions with a lot of passenger inflow from affected countries worldwide if there are even small local pockets of unvaccinated people. “The New York borough of Brooklyn is a perfect example with a large number of unvaccinated members of an orthodox Jewish community even though the overall county vaccination rate is not low.”

Other authors on this study include Aleksa Zlojutro of the University of New South Wales Sydney and Kamran Khan of St. Michaels Hospital in Toronto.

And while the billion-dollar Laser Interferometer Gravitational-Wave Observatory (LIGO) detector watches 24/7 for gravitational waves to pass through the Earth, new research shows those waves leave behind plenty of “memories” that could help detect them even after they’ve passed.

“That gravitational waves can leave permanent changes to a detector after the gravitational waves have passed is one of the rather unusual predictions of general relativity,” said doctoral candidate Alexander Grant, lead author of “Persistent Gravitational Wave Observables: General Framework,” published April 26 in Physical Review D.

Physicists have long known that gravitational waves leave a memory on the particles along their path, and have identified five such memories. Researchers have now found three more aftereffects of the passing of a gravitational wave, “persistent gravitational wave observables” that could someday help identify waves passing through the universe.

Each new observable, Grant said, provides different ways of confirming the theory of general relativity and offers insight into the intrinsic properties of gravitational waves.

Those properties, the researchers said, could help extract information from the Cosmic Microwave Background — the radiation left over from the Big Bang.

“We didn’t anticipate the richness and diversity of what could be observed,” said Éanna Flanagan, the Edward L. Nichols Professor and chair of physics and professor of astronomy.

“What was surprising for me about this research is how different ideas were sometimes unexpectedly related,” said Grant. “We considered a large variety of different observables, and found that often to know about one, you needed to have an understanding of the other.”

The researchers identified three observables that show the effects of gravitational waves in a flat region in spacetime that experiences a burst of gravitational waves, after which it returns again to being a flat region. The first observable, “curve deviation,” is how much two accelerating observers separate from one another, compared to how observers with the same accelerations would separate from one another in a flat space undisturbed by a gravitational wave.

The second observable, “holonomy,” is obtained by transporting information about the linear and angular momentum of a particle along two different curves through the gravitational waves, and comparing the two different results.

The third looks at how gravitational waves affect the relative displacement of two particles when one of the particles has an intrinsic spin.

Each of these observables is defined by the researchers in a way that could be measured by a detector. The detection procedures for curve deviation and the spinning particles are “relatively straightforward to perform,” wrote the researchers, requiring only “a means of measuring separation and for the observers to keep track of their respective accelerations.”

Detecting the holonomy observable would be more difficult, they wrote, “requiring two observers to measure the local curvature of spacetime (potentially by carrying around small gravitational wave detectors themselves).” Given the size needed for LIGO to detect even one gravitational wave, the ability to detect holonomy observables is beyond the reach of current science, researchers say.

“But we’ve seen a lot of exciting things already with gravitational waves, and we will see a lot more. There are even plans to put a gravitational wave detector in space that would be sensitive to different sources than LIGO,” Flanagan said.

Also contributing were Abraham Harte, Dublin City University, Ireland; and David Nichols, University of Amsterdam, The Netherlands.

This work was supported by the National Science Foundation and the Netherlands Organization for Scientific Research.

However, even high-end conventional radiation thermometers have produced readings with worryingly large uncertainties. But now researchers at the National Institute of Standards and Technology (NIST) have invented a portable, remarkably stable standards-quality radiation thermometer about 60 centimeters (24 inches) long that is capable of measuring temperatures to a precision of within a few thousandths of a degree Celsius.

NIST has a long history of studying radiation thermometers. The new prototype instrument, which builds on that work, can measure temperatures between -50 C (-58 F) to 150 C (302 F). The corresponding infrared wavelengths are from 8 to 14 micrometers (millionths of a meter), which is a sort of thermodynamic sweet spot.

“All temperatures are equal, but some are more equal than others,” said NIST physicist Howard Yoon, who created the thermometer design and directed the project, described in the journal Optics Express. “That 200-degree span covers nearly all naturally occurring temperatures on Earth. If you make a big impact in measuring objects in that range, it really matters.”

In addition to clinical medicine, temperatures in that region are of urgent importance in applications where contact is not appropriate or feasible. For example, surgeons need to measure the temperature of organs prior to transplant. Modern farmers need accurate temperatures when handling, storing and processing food. Satellites require non-contact thermometers for measuring temperatures on land and the surface of the sea.

Conventional radiation thermometers often contain little more than a lens for focusing the infrared radiation and a pyroelectric sensor, a device that converts heat energy into an electrical signal. Their measurements can be affected by temperature differences along the thermometer and by temperature outside the instrument.

The NIST design, called the Ambient-Radiation Thermometer (ART), is fitted with a suite of interior thermometers that constantly gauge temperatures at different points in the instrument. Those readings are sent to a feedback loop system which keeps the 30-cm (12-inch) cylinder containing the detector assembly at a constant temperature of 23 C (72 F).

It also features other design improvements, including a method for reducing errors from what is called the size-of-source effect, which results when radiation enters the instrument from areas outside its specified field of view.

The ART’s major advantage is its unprecedented stability. After it has been calibrated against standards-grade contact thermometers, the instrument can remain stable to within a few thousandths of a degree for months under continuous operation. That makes the system very promising for applications that involve remote sensing over long periods.

“Imagine being able to take the NIST design out in the field as traveling radiation thermometers for accurately measuring variables such as land- and sea-surface temperatures,” Yoon said. “It could serve as a trustworthy method of calibrating satellite IR sensors and validating the huge weather science programs that are used to predict, for example, the paths and strengths of hurricanes.” Its lower range of -50 C (-58 F) makes it suitable for monitoring the temperature of ice over polar regions, typically in the range of -40 C (-40 F) to -10 C (14 F).

There are several methods of making very high-accuracy temperature measurements, but few are well-suited to field work. Platinum resistance thermometers are fragile and need frequent recalibration. The standard temperature source for transferring that calibration to the ART involves a heat-source cavity inside about 42 liters (11 gallons) of liquid.

“Those are the best sources we have,” Yoon said. “But it is impractical to measure water temperature by putting a thermometer in the ocean at intervals, and you don’t want to constantly calibrate your radiation thermometer using a calibration source like that on board a ship.”

Gerald Fraser, chief of NIST’s Sensor Science Division, said that “Yoon’s innovation makes non-contact thermometry competitive with the best commercial contact thermometers in accuracy and stability in a temperature range that humans experience daily. This enables many new opportunities in product inspection and quality control and in defense and security where conventional contact methods are impractical or too expensive.”