Background cosmological dynamics in f(R)f(R) gravity and observational constraints

In this paper, we carry out a study of viable cosmological models in $f(R)$-gravity at the background level. We use observable parameters like $\Omega$ and $\gamma$ to form autonomous system of equations and show that the models under consideration exhibit two different regimes in their time evolution, namely, a phantom phase followed by a quintessence like behavior. We employ statefinder parameters to emphasize a characteristic discriminative signature of these models.Comment: 6 pages, Latex style, 9 eps figures, replaced versions with new references added, Submitted to Phys.Rev.

Placement of Outdoor Exercise Equipment and Physical Activity: A Quasi-Experimental Study in Two Parks in Southern California.

To reduce the burden of chronic disease, the Centers for Disease Control and Prevention (CDC) funded the Orange County Partnerships to Improve Health (OC-PICH) project in Orange County, California. One of the strategies included adding outdoor exercise equipment (OEE) in two parks in Garden Grove and Anaheim. Using a quasi-experimental pre-post design, we evaluated park users' physical activity levels before and after OEE installation using the System for Observing Play and Recreation in Communities (SOPARC). The OEE was installed along a walking path in Edison Park (Anaheim) and grouped within a single area (a "fitness zone") in Garden Grove Park. In both parks, there were significantly greater odds of high-intensity physical activity overall after the installation-19% higher odds in Anaheim, and 23% higher odds in Garden Grove. However, the fitness zone area in Garden Grove had substantially higher odds of increased physical activity post-intervention (OR = 5.29, CI: 3.76-7.44, p < 0.001). While the increases in physical activity levels are consistent with past studies that link OEE to higher levels of physical activity among park users, our findings also suggest that the location and placement of equipment within a park may be an important factor to consider when improving park amenities for physical activity

Lessons Learned and Next Steps in Energy Efficiency Measurement and Attribution: Energy Savings, Net to Gross, Non-Energy Benefits, and Persistence of Energy Efficiency Behavior

This white paper examines four topics addressing evaluation, measurement, and attribution of direct and indirect effects to energy efficiency and behavioral programs: Estimates of program savings (gross); Net savings derivation through free ridership / net to gross analyses; Indirect non-energy benefits / impacts (e.g., comfort, convenience, emissions, jobs); and, Persistence of savings

ALMA detection of dark chromospheric holes in the quiet Sun

We present Atacama Large Millimeter/submillimeter Array (ALMA) observations of a quiet-Sun region at a wavelength of 3 mm, obtained during the first solar ALMA cycle on April 27, 2017, and compare them with available chromospheric observations in the UV and visible as well as with photospheric magnetograms. ALMA images clearly reveal the presence of distinct particularly dark/cool areas in the millimeter maps having temperatures as low as 60% of the normal quiet Sun at 3 mm, which are not seen in the other data. We speculate that ALMA is sensing cool chromospheric gas, whose presence had earlier been inferred from infrared CO spectra.Comment: 9 pages, 3 figures, accepted for publication in ApJ

The relationship between chromospheric emissions and magnetic field strength

Aims. We analyze observational data from 4 instruments to study the correlations between chromospheric emission, spanning the heights from the temperature minimum region to the middle chromosphere, and photospheric magnetic field. Methods: The data consist of radio images at 3.5 mm from the Berkeley-Illinois-Maryland Array (BIMA), UV images at 1600 A from TRACE, Ca II K-line filtergrams from BBSO, and MDI/SOHO longitudinal photospheric magnetograms. For the first time interferometric millimeter data with the highest currently available resolution are included in such an analysis. We determine various parameters of the intensity maps and correlate the intensities with each other and with the magnetic field. Results: The chromospheric diagnostics studied here show a pronounced similarity in their brightness structures and map out the underlying photospheric magnetic field relatively well. We find a power law to be a good representation of the relationship between photospheric magnetic field and emission from chromospheric diagnostics at all wavelengths. The dependence of chromospheric brightness on magnetic field is found to be different for network and internetwork regions.Comment: 13 pages, 14 figures, 3 table