Zooming in on accretion - II. Cold Circumgalactic Gas Simulated with a super-Lagrangian Refinement Scheme

In this study we explore the complex multi-phase gas of the circumgalactic medium (CGM) surrounding galaxies. We propose and implement a novel, super-Lagrangian 'CGM zoom' scheme in the moving-mesh code AREPO, which focuses more resolution into the CGM and intentionally lowers resolution in the dense ISM. We run two cosmological simulations of the same galaxy halo, once with a simple 'no feedback' model, and separately with a more comprehensive physical model including galactic-scale outflows as in the Illustris simulation. Our chosen halo has a total mass of ~10^12 Msun at z ~ 2, and we achieve a median gas mass (spatial) resolution of ~2,200 solar masses (~95 parsecs) in the CGM, six-hundred (fourteen) times better than in the Illustris-1 simulation, a higher spatial resolution than any cosmological simulation at this mass scale to date. We explore the primary channel(s) of cold-phase CGM gas production in this regime. We find that winds substantially enhance the amount of cold gas in the halo, also evidenced in the covering fractions of HI and the equivalent widths of MgII out to large radii, in better agreement with observations than the case without galactic winds. Using a tracer particle analysis to follow the thermodynamic history of gas, we demonstrate how the majority of this cold, dense gas arises due to rapid cooling of the wind material interacting with the hot halo, and how large amounts of cold, ~10^4 K gas can be produced and persist in galactic halos with Tvir ~ 10^6 K. At the resolutions presently considered, the quantitative properties of the CGM we explore are not appreciably affected by the refinement scheme.Comment: MNRAS submitted, comments welcome. High-res version at http://www.mpa-garching.mpg.de/~dnelson/papers/Suresh19_zooming2.pd

The monetary value of diets consumed by British adults: an exploration into sociodemographic differences in individual-level diet costs

OBJECTIVE: To describe the diet costs of adults in the National Diet and Nutrition Study (NDNS) and explore patterns in costs according to sociodemographic indicators. DESIGN: Cross-sectional diet diary information was matched to a database of food prices to assign a cost to each food or non-alcoholic beverage consumed. Daily diet costs were calculated, as well as costs per 10 MJ to improve comparability across differing energy requirements. Costs were compared between categories of sociodemographic variables and health behaviours. Multivariable regression assessed the effects of each variable on diet costs after adjustment. SETTING: The NDNS is a rolling dietary survey, recruiting a representative UK sample each year. The study features data from 2008-2010. SUBJECTS: Adults aged 19 years or over were included. The sample consisted of 1014 participants. RESULTS: The geometric mean daily diet cost was £2·89 (95 % CI £2·81, £2·96). Energy intake and daily diet cost were strongly associated. The mean energy-adjusted cost was £4·09 (95 % CI £4·01, £4·18) per 10 MJ. Energy-adjusted costs differed significantly between many subgroups, including by sex and household income. Multivariable regression found significant effects of sex, qualifications and occupation (costs per 10 MJ only), as well as equivalized household income, BMI and fruit and vegetable consumption on diet costs. CONCLUSIONS: This is the first time that monetary costs have been applied to the diets of NDNS adults. The findings suggest that certain subgroups in the UK - for example those on lower incomes - consume diets of lower monetary value. Observed differences were mostly in the directions anticipated

Downtown Providence Farmers Market Design

This market essentially combines a marketplace with an existing or new industrial building. The hybrid created results in space that has daily retail sales and hours, as well as other goods available at other times. The industrial aspect typically acts as the anchor, as the market’s activities help attract a different group of consumers at other business times. An example of this would be a seafood supply warehouse that also provides dining and entertainment as a nightlife destination

The evolution of post-starburst galaxies from z=2 to 0.5

We present the evolution in the number density and stellar mass functions of photometrically selected post-starburst galaxies in the UKIDSSUltraDeep Survey,with redshifts of 0.510. We find that this transitionary species of galaxy is rare at all redshifts, contributing ∼5 per cent of the total population at z ∼ 2, to <1 per cent by z ∼ 0.5. By comparing the mass functions of quiescent galaxies to post-starburst galaxies at three cosmic epochs, we show that rapid quenching of star formation can account for 100 per cent of quiescent galaxy formation, if the post-starburst spectral features are visible for ∼250 Myr. The flattening of the low-mass end of the quiescent galaxy stellar mass function seen at z ∼ 1 can be entirely explained by the addition of rapidly quenched galaxies. Only if a significant fraction of post-starburst galaxies have features that are visible for longer than 250 Myr, or they acquire new gas and return to the star-forming sequence, can there be significant growth of the red sequence from a slower quenching route. The shape of the mass function of these transitory post-starburst galaxies resembles that of quiescent galaxies at z ∼ 2, with a preferred stellar mass of log (M/M�) ∼10.6, but evolves steadily to resemble that of star-forming galaxies at z /~ 2 they are exclusively massive galaxies that have formed the bulk of their stars during a rapid assembly period, followed by complete quenching of further star formation; (2) at z </~1 they are caused by the rapid quenching of gas-rich star-forming galaxies, independent of stellar mass, possibly due to environment and/or gas-rich major mergers

Wildfires & Prescribed Fires: Do They Impact Soil Quality?

Globally, climate change has had an adverse effect on natural phenomena and ecosystem trends, including drastically increasing the number of wildfires that occur annually. As a result, the number of wildfires in the western United States have doubled since 1984. More specifically, ideal wildfire conditions have also prolonged the wildfire season in California. The objectives of this study were to determine if wildfires had an effect on soil quality and determine if wildfires and prescribed fires had different impacts on soil quality in northern California. A literature review was conducted to address the knowledge gaps and understand the perceived changes in soil quality due to wildfires and prescribed fires found in previous studies. A meta-data analysis of soil sample data and wildfire and prescribed fire data was conducted to find any differences in soil quality before and after both wildfires or prescribed fires occurred. Next, the soil sample data was analyzed to determine if any significant changes in soil quality differed due to the type of fire. The results of this study were deemed inconclusive because of a lack of data and other confounding variables. However, it provided insight to possible future directions and provided a baseline of understanding of why a more in-depth study on the relationship between soil quality and wildfires is needed

Surface passivation of carbon nanoparticles with branched macromolecules influences near infrared bioimaging

A superior and commercially exploitable 'green synthesis' of optically active carbon nanoparticle (OCN) is revealed in this work. The naked carbon particles (<20 nm) were derived from commercial food grade honey. The fluorescence properties of these particles were significantly enhanced by utilizing hyberbranched polymer for surface passivation. A dramatic increase in near infrared emission was achieved compared to a linear polymer (PEG) coated carbon nanoparticles. Interestingly, as passivating agent becomes more extensively branched (pseudo generation 2 to 4), the average radiant efficiency amplifies considerably as a direct result of the increasing surface area available for light passivation. The particles showed negligible loss of cell viability in presence of endothelial cells in vitro. Preliminary in vivo experiment showed high contrast enhancement in auxiliary lymphnode in a mouse model. The exceptionally rapid lymphatic transport of these particles suggests that such an approach may offer greater convenience and reduced procedural expense, as well as improved surgical advantage as the patient is positioned on the table for easier resection

Global norms, organisational change: framing the rights-based approach at ActionAid

This article examines the adoption of the rights-based approach (RBA) to development at ActionAid International, focusing in particular on its Education Theme. Although there has been a considerable volume of work that examines the rise of RBA, including in the pages of Third World Quarterly, the power dynamics and conflict involved in shifting to RBA have largely gone unnoticed and explored. Using the methodological tools of discourse analysis and social movement theory on strategic issue framing, I examine how ActionAid leadership worked to ‘sell’ RBA to somewhat-resistant staff and partners. I argue that ActionAid struggled to reconcile its commitment to global rights norms with the ongoing needs-based programming at country-level. This raises important questions about the power dynamics involved when an NGO undergoes a process of organisational change, even when, as is the case with RBA, this is widely seen as a progressive and desirable transition

Causes Won, Lost, and Forgotten: How Hollywood and Popular Art Shape What We Know About the Civil War

Picturing the Civil War Gary W. Gallagher has done his fair share of shaping what historians know about the Civil War. In his latest book, Causes Won, Lost and Forgotten, he investigates how modern film and artworks determine what the American public knows about the conflict. I...

The Gray Needle: Large Grains in the HD 15115 Debris Disk from LBT/PISCES/Ks and LBTI/LMIRcam/L' Adaptive Optics Imaging

We present diffraction-limited \ks band and \lprime adaptive optics images of the edge-on debris disk around the nearby F2 star HD 15115, obtained with a single 8.4 m primary mirror at the Large Binocular Telescope. At \ks band the disk is detected at signal-to-noise per resolution element (SNRE) \about 3-8 from \about 1-2\fasec 5 (45-113 AU) on the western side, and from \about 1.2-2\fasec 1 (63-90 AU) on the east. At \lprime the disk is detected at SNRE \about 2.5 from \about 1-1\fasec 45 (45-90 AU) on both sides, implying more symmetric disk structure at 3.8 \microns . At both wavelengths the disk has a bow-like shape and is offset from the star to the north by a few AU. A surface brightness asymmetry exists between the two sides of the disk at \ks band, but not at \lprime . The surface brightness at \ks band declines inside 1\asec (\about 45 AU), which may be indicative of a gap in the disk near 1\asec. The \ks - \lprime disk color, after removal of the stellar color, is mostly grey for both sides of the disk. This suggests that scattered light is coming from large dust grains, with 3-10 \microns -sized grains on the east side and 1-10 \microns dust grains on the west. This may suggest that the west side is composed of smaller dust grains than the east side, which would support the interpretation that the disk is being dynamically affected by interactions with the local interstellar medium.Comment: Apj-accepted March 27 2012; minor correction