National Bureau of Economic Research

National Bureau of Economic Research

National Bureau of Economic Research

National Bureau of Economic Research

National Bureau of Economic Research

“You cannot feed the people with communal sentiments indefinitely,” the Congress leader said in an interview to The Hindu, where he also dismissed concerns about factionalism within the party

It lifted off atop a SpaceX Falcon 9 rocket today at after 5:23 a.m. EDT (2:54 PM IST) from historic Launch Complex-39A at NASA's Kennedy Space Center (KSC).

In confined spaces, water’s dielectric constant drops dramatically, according to new measurements

A polar vortex has blasted into the northeastern US this weekend bringing rare May snowfall and record low temperatures to some areas.

Many in the region had to dust off their snow shovels for at least one more dig out on Saturday morning after a polar vortex blasted parts of the province, catching many off guard.

Protease-activated receptor 2 (PAR-2) is activated by secreted proteases from immune cells or fungi. PAR-2 is normally expressed basolaterally in differentiated nasal ciliated cells. We hypothesized that epithelial remodeling during diseases characterized by cilial loss and squamous metaplasia may alter PAR-2 polarization. Here, using a fluorescent arrestin assay, we confirmed that the common fungal airway pathogen Aspergillus fumigatus activates heterologously-expressed PAR-2. Endogenous PAR-2 activation in submerged airway RPMI 2650 or NCI–H520 squamous cells increased intracellular calcium levels and granulocyte macrophage–colony-stimulating factor, tumor necrosis factor α, and interleukin (IL)-6 secretion. RPMI 2650 cells cultured at an air–liquid interface (ALI) responded to apically or basolaterally applied PAR-2 agonists. However, well-differentiated primary nasal epithelial ALIs responded only to basolateral PAR-2 stimulation, indicated by calcium elevation, increased cilia beat frequency, and increased fluid and cytokine secretion. We exposed primary cells to disease-related modifiers that alter epithelial morphology, including IL-13, cigarette smoke condensate, and retinoic acid deficiency, at concentrations and times that altered epithelial morphology without causing breakdown of the epithelial barrier to model early disease states. These altered primary cultures responded to both apical and basolateral PAR-2 stimulation. Imaging nasal polyps and control middle turbinate explants, we found that nasal polyps, but not turbinates, exhibit apical calcium responses to PAR-2 stimulation. However, isolated ciliated cells from both polyps and turbinates maintained basolateral PAR-2 polarization, suggesting that the calcium responses originated from nonciliated cells. Altered PAR-2 polarization in disease-remodeled epithelia may enhance apical responses and increase sensitivity to inhaled proteases.

The popular saying "April showers bring May flowers" might not be the case this year. The northeastern United States is experiencing an unusual Mother's Day weekend as most restaurants remain closed amid coronavirus concerns and a historic polar vortex packing snow shatters temperature records. Freeze watches and warnings along with frost advisories were put into effect Friday night for many places across parts of the Midwest, down into the Southeast and into the Northeast.

Mother’s Day weekend got off to an unseasonably snowy start in the Northeast on Saturday thanks to the polar vortex bringing cold air down from the north. John Cannon, a meteorologist with the National Weather Service in Gray, Maine, said parts of northern New England saw as much as 10 inches of snow and even coastal areas of Maine and New Hampshire got a dusting.

The polar bear, floating mournfully away on an ice floe as his habitat melts around him, is perhaps one of the most well-travelled symbols of the impacts of climate change.

Polar Vortex has blasted into the northeast with record low temperatures, winds and snow. Mt. Washington has a low of just 10 degrees, while Death Valley, California, is could reach 110 degrees.

The time evolution of the electron density and the resulting time dependence of the X-ray polarizability of a crystal irradiated by highly intense XFEL femtosecond pulses is investigated theoretically. Rate equations for bound electrons and the Boltzmann equation for the unbound electron gas are used in calculations.

A Thomson scattering X-ray source can provide quasi-monochromatic, continuously energy-tunable, polarization-controllable and high-brightness X-rays, which makes it an excellent tool for X-ray fluorescence computed tomography (XFCT). In this paper, we examined the suppression of Compton scattering background in XFCT using the linearly polarized X-rays and the implementation feasibility of linearly polarized XFCT based on this type of light source, concerning the influence of phantom attenuation and the sampling strategy, its advantage over K-edge subtraction computed tomography (CT), the imaging time, and the potential pulse pile-up effect by Monte Carlo simulations. A fan beam and pinhole collimator geometry were adopted in the simulation and the phantom was a polymethyl methacrylate cylinder inside which were gadolinium (Gd)-loaded water solutions with Gd concentrations ranging from 0.2 to 4.0 wt%. Compared with the case of vertical polarization, Compton scattering was suppressed by about 1.6 times using horizontal polarization. An accurate image of the Gd-containing phantom was successfully reconstructed with both spatial and quantitative identification, and good linearity between the reconstructed value and the Gd concentration was verified. When the attenuation effect cannot be neglected, one full cycle (360°) sampling and the attenuation correction became necessary. Compared with the results of K-edge subtraction CT, the contrast-to-noise ratio values of XFCT were improved by 2.03 and 1.04 times at low Gd concentrations of 0.2 and 0.5 wt%, respectively. When the flux of a Thomson scattering light source reaches 1013 photons s−1, it is possible to finish the data acquisition of XFCT at the minute or second level without introducing pulse pile-up effects.

Image right: A sea of dunes, sculpted by the wind into long lines, surrounds the northern polar cap of Mars, covering an area as big […]

The post Mars polar dunes appeared first on Smithsonian Insider.

All bear species except for one live in either temperate or tropical woodlands. Only the polar bear is a stranger to the forest, living and […]

The post Polar bears in a warming world: Q&A with Don Moore of the National Zoo appeared first on Smithsonian Insider.

The moon passed between the Earth and the sun on Thursday, Oct. 23. While avid stargazers in North America looked up to watch the spectacle, the […]

The post Polar-orbiting satellite captures amazing X-ray footage of solar eclipse appeared first on Smithsonian Insider.

Combining sodium hydride with some solvents can be a bad idea, as a group of researchers from Corteva Agriscience and Dow Chemical remind the chemistry community in Organic Process Research & Development ,(2019, DOI: 10.1021/acs.oprd.9b00276). Reports of explosions from combining NaH with a polar aprotic solvent such as dimethyl sulfoxide (DMSO), N,N-dimethylformamide (DMF), and N,N-dimethylacetamide […]

The post Don’t mix sodium hydride with polar aprotic solvents appeared first on CENtral Science.

The U.S. lacks icebreaking capability in the Arctic and Antarctic and should build four polar icebreakers with heavy icebreaking capability to help minimize the life-cycle costs of icebreaker acquisition and operations, says a new congressionally mandated letter report from the National Academies of Sciences, Engineering, and Medicine.

Despite Atlantic cod and haddock extending further into Arctic waters, a new study reveals there is little competition for food between the invaders and native polar cod. However, it is uncertain whether climate change will increase competition between the species as range expansion of the Atlantic species progresses.

Researchers have demonstrated that hatching in polar cod can begin as early as January in Arctic seas that receive large freshwater input, compared to April-July in seas with little freshwater input. Since early hatching leads to higher survival rates, the effects of climate change may enhance polar cod’s survival by favouring conditions that allow winter hatching to occur.

Climate change could alter the species diversity of an important type of polar bacterial community, according to laboratory tests. At temperatures similar to those forecasted using current climate warming rates, researchers observed an increase in toxin-producing bacteria that could alter freshwater polar ecosystems.

Increased sea ice drift forces polar bears to expend more energy walking on a fast-moving 'treadmill' of sea ice.

Wildlife photographer Michel Rawicki captures polar bears in their private moments.