Sunday, December 04, 2016

ScienceBlogs Channel : Physical Science

ScienceBlogs Channel : Physical Science


Ask Ethan: How Do Gravitational Waves Escape From A Black Hole? (Synopsis) [Starts With A Bang]

Posted: 03 Dec 2016 07:42 AM PST

“I think there are a number of experiments that are thinking about how you could look in different frequency bands, and get a glimpse of the primordial gravitational wave background. I think that would be really revolutionary, because that would be your first glimpse at the very first instant of our Universe.” -Dave Reitze, LIGO’s executive director

Black holes are remarkable entities that have puzzled and fascinated us since they were first postulated long before Einstein developed his theory of relativity. One of their fundamental but bizarre properties is the fact that once something crosses or winds up inside the event horizon, it can not only never escape, it heads inevitably towards the central singularity. At that point, the only "information" about the singularity is its mass, charge (of various types), and spin.

Illustration of a black hole and its surrounding, accelerating and infalling accretion disk. The singularity is hidden behind the event horizon. Image credit: NASA.

Illustration of a black hole and its surrounding, accelerating and infalling accretion disk. The singularity is hidden behind the event horizon. Image credit: NASA.

Yet when two merging black holes coalesced together, as seen multiple times by LIGO, the mass of the final black hole was approximately 5% less than the sum of the masses of the two black hole progenitors. If nothing massive or massless can escape through the event horizon, how did this energy get out?

Any object or shape, physical or non-physical, would be distorted as gravitational waves passed through it. Note how no waves are ever emitted from inside the black hole's event horizon. Image credit: NASA/Ames Research Center/C. Henze.

Any object or shape, physical or non-physical, would be distorted as gravitational waves passed through it. Note how no waves are ever emitted from inside the black hole’s event horizon. Image credit: NASA/Ames Research Center/C. Henze.

Our intuitions might lead us astray, but the mathematics provides a straightforward explanation that's not so different from other physics you might be used to. Come find out on this edition of Ask Ethan!

Saturday, December 03, 2016

ScienceBlogs Channel : Medicine & Health

ScienceBlogs Channel : Medicine & Health


CDC: Health care workers report highest rates of asthma [The Pump Handle]

Posted: 02 Dec 2016 03:24 PM PST

More than 2 million U.S. adults may be living with workplace-related asthma, according to new data from the Centers for Disease Control and Prevention.

Published this week in CDC's Morbidity and Mortality Weekly Report, the study is based on data from the 2013 Behavioral Risk Factor Surveillance System (BRFSS) industry and occupational module, which gathered information from 21 states for adults ages 18 and older who were employed or had been out of work for one year or less. Among the survey respondents, 7.7 percent had asthma, with researchers estimating that upward of 2.7 million adults might be living with asthma that was either caused by workplace exposures or had asthma exacerbated by workplace conditions. The BRFSS' industry and occupational module was administered in 2013 for the first time in 19 states, and more than 208,000 adults across 21 states participated in the work-related module.

Overall, prevalence of asthma among workers ranged from 5 percent in Mississippi to 10 percent in Michigan, with the highest rates among workers in health care, health care support and social assistance. The state-specific analysis found that asthma prevalence was highest among workers in Massachusetts' information industry, at 18 percent, and among health care support workers in Michigan, at more than 21 percent. Among the top five industries with the highest prevalence of asthma, health care and social assistance, retail trade and education were identified in a majority of states surveyed. Study co-authors Katelynn Dodd and Jacek Mazurek write:

Persons with work-related asthma have more symptomatic days, use more health care resources, and have lower quality of life. Moreover, asthma exacerbations accelerate decline in lung function. Each of the industries and occupations identified in this report is associated with a specific set of existing and emerging workplace exposures, including irritant chemicals, dusts, secondhand smoke, allergens, emotional stress, temperature, and physical exertion, that have been associated with new-onset and work-exacerbated asthma. For example, it is well recognized that workers in the health care and social assistance industry who are exposed to cleaning and disinfection products, powdered latex gloves, and aerosolized medications have a twofold-increased likelihood of new-onset asthma. A previous study reported that as much as 48% of adult asthma is caused or made worse by work; therefore, as many as 2.7 million workers might have asthma caused or exacerbated by workplace conditions in these 21 states.

Digging deeper into the details, the study found that among workers surveyed in the 21 states, asthma rates were nearly twice as high among women when compared to men, at 5.7 percent versus 10.2 percent. Current asthma was also highest among blacks, at 8.9 percent, followed by whites at 8.1 percent and Hispanics at 6.5 percent. Workers in the lowest household income category, at $15,000 or less, also reported the highest asthma rates. At the state level, Massachusetts, Michigan and Oregon were home to highest percentages of workers with asthma; Mississippi, Nebraska and Louisiana had the lowest.

When ranking industries, researchers found that health care and social assistance topped the list, with 10.7 percent of workers reporting current asthma. The five industries that followed were education, at 9.1 percent; arts, entertainment and recreation, at 9 percent; information, at 8.7 percent; retail trade, also at 8.7 percent; and finance and insurance, at 8.4 percent. When ranking according to occupation, health care support took the top spot, with 12.4 percent of workers reporting current asthma. The five occupations that followed were community and social services, at 12.2 percent; personal care and service, at 12.1 percent; arts, design, entertainment, sports and media, at 11.7 percent; office and administrative support, at 10.2 percent; and health care practitioners and technicians, at 9.2 percent.

The study also breaks down the percentage of workers who report asthma by industry and occupation within states. For example, in California, the industry with the highest rate of asthma is education, while the occupation with the highest rate is personal care and service.

"Potential work-related asthma exposure can be identified, and effective prevention and education strategies can be implemented," the researchers write. "Routine collection of industry and occupation information is needed to estimate state-specific work-related asthma prevalence by respondents' industry and occupation."

According to OSHA, about 11 million U.S. workers face exposure to conditions related to occupational asthma, with workplace factors related to upwards of 15 percent of disabling asthma cases.

Read the full study at MMWR.

Kim Krisberg is a freelance public health writer living in Austin, Texas, and has been writing about public health for 15 years.

ScienceBlogs Channel : Physical Science

ScienceBlogs Channel : Physical Science


LHC’s newest data: a victory for the Standard Model, defeat for new physics [Starts With A Bang]

Posted: 02 Dec 2016 07:01 AM PST

"There is nothing new to be discovered in physics now. All that remains is more and more precise measurement." -Lord Kelvin

The particle physics 'nightmare scenario' was that the LHC at CERN would achieve its desired energies and collision rates, that it would find a single Higgs boson between about 120 and 140 GeV, and that it would see absolutely nothing else. No new particles, no bizarre decays, nothing that couldn't be accounted for by the Standard Model. With the latest release, that's exactly what's happening.

The observed Higgs decay channels vs. the Standard Model agreement, with the latest data from ATLAS and CMS included. The agreement is astonishing. Images credit: André David, via Twitter.

The observed Higgs decay channels vs. the Standard Model agreement, with the latest data from ATLAS and CMS included. The agreement is astonishing. Images credit: André David, via Twitter.

There's no evidence at any appreciable significance for any new particles or interactions, and no compelling reason to expect that a larger, higher-energy collider will find anything new. Unless the LHC pulls out a surprise over the coming years, the Standard Model might be it for what high-energy colliders are capable of finding here on Earth.

A hypothetical new accelerator, either a long linear one or one encircling the Earth, could dwarf the LHC's energies, but still might not find anything new. Image credit: ILC collaboration.

A hypothetical new accelerator, either a long linear one or one encircling the Earth, could dwarf the LHC’s energies, but still might not find anything new. Image credit: ILC collaboration.

Come find out what the latest data says about where we are in the hunt for new physics, and remember to be skeptical of claims to the contrary!

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