A 3-dimensional numerical simulation of the atmospheric injection of aerosols by a hypothetical basaltic fissure eruption

Researchers simulated the atmospheric response to a hypothetical basaltic fissure eruption using heating rates based on the Roza flow eruption. The simulation employs the Colorado State University Regional Atmospheric Model (RAMS) with scavenging effects. The numerical model is a three-dimensional non-hydrostatic time-split compressible cloud/mesoscale model. Explicit microphysics include prediction of cloud, rain, crystal, and hail precipitation types. Nucleation and phoretic scavenging are predicted assuming that the pollutant makes an effective cloud droplet nucleus. Smoke is carried as a passive tracer. Long and short wave radiation heating tendencies, including the effects of the smoke, are parameterized. The longwave emission by the lava surface is neglected in the parameterization and included as an explicit heating term instead. A regional scale domain of 100 x 100 km in the horizontal and 22 km high is used. The horizontal grid spacing is taken to be 2 km and the vertical spacing is taken to be 0.75 km. The initial atmospheric state is taken to be horizontally homogenous and based on the standard atmospheric sounding. The fissure is assumed to be 90 km long and oriented in a zig/zag pattern

Inclusive deuteron-induced reactions and final neutron states

We present in this paper a formalism for deuteron-induced inclusive reactions. We disentangle direct elastic breakup contributions from other processes (which we generically call non-elastic breakup) implying a capture of the neutron both above and below the neutron emission threshold. The reaction is described as a two step process, namely the breakup of the deuteron followed by the propagation of the neutron-target system driven by an optical potential. The final state interaction between the neutron and the target can eventually form an excited compound nucleus. Within this context, the direct neutron transfer to a sharp bound state is a limiting case of the present formalism.Comment: To appear in the proceedings of the 14th International Conference on Nuclear Reaction Mechanisms, Varenna, Ital

Understanding Transit Ridership Demand for a Multi-Destination, Multimodal Transit Network in an American Metropolitan Area, Research Report 11-06

This study examines the factors underlying transit demand in the multi-destination, integrated bus and rail transit network for Atlanta, Georgia. Atlanta provides an opportunity to explore the consequences of a multi-destination transit network for bus patrons (largely transit-dependent riders) and rail patrons (who disproportionately illustrate choice rider characteristics). Using data obtained from the 2000 Census, coupled with data obtained from local and regional organizations in the Atlanta metropolitan area, we estimate several statistical models that explain the pattern of transit commute trips across the Atlanta metropolitan area. The models show that bus riders and rail riders are different, with bus riders exhibiting more transit-dependent characteristics and rail riders more choice rider characteristics. However, both types of riders value many of the same attributes of transit service quality (including shorter access and egress times and more direct trips) and their use of transit is influenced by many of the same variables (including population and employment). At the same time, the factors that influence transit demand vary depending on the type of travel destination the rider wishes to reach, including whether it is the central business district (CBD) or a more auto-oriented, suburban destination. The results of the study offer new insights into the nature of transit demand in a multi-destination transit system and provide lessons for agencies seeking to increase ridership among different ridership groups. The results suggest that more direct transit connections to dispersed employment centers, and easier transfers to access such destinations, will lead to higher levels of transit use for both transit-dependent and choice riders. The results also show that the CBD remains an important transit destination for rail riders but not for their bus rider counterparts. Certain types of transit-oriented development (TOD) also serve as significant producers and attractors of rail transit trips

Colony Stimulating Factor-1 Receptor (CSF-1R) Expression, Degradation, and Signaling in Lipid-Laden Macrophages

Atherosclerosis is a serious disease affecting a large portion of the world’s population. In atherosclerosis, macrophages become filled with lipid droplets and form fatty plaques in artery walls. The formation of these atherosclerotic plaques is dependent on the macrophage growth factor colony stimulating factor-1 (CSF-1); however, understanding the changes in CSF-1 signaling and related pathways in foam cells remain poorly investigated. Lipid-laden macrophages were formed through exposure of murine bone marrow derived macrophages to 100 μg/ml acetylated LDL for 24 h. Non-LDL treated macrophages were grown in parallel for each experiment and used for comparison. Immunofluorescent staining was used to visualize and quantify CSF-1R, pAkt, pERK, pCSF-1R, and Ki67. To synchronize the signaling process, macrophages were deprived of CSF-1 supplemented media before experiments. The lipid-laden macrophages had a decreased rate of CSF-1R expression. The degradation of CSF-1R was unchanged after the initial CSF-1 stimulation, but the level of phosphorylated receptor was lower in lipid-laden macrophages. The phosphorylation of Akt was unchanged during the first hour but increased in non-LDL exposed cells after 10 h. The phosphorylation of ERK spiked in non-LDL exposed cells at 7 min indicating a possible differential activation of pathways. Macrophage proliferation, as measured by Ki67 staining, increased while the cells had lipid droplets then leveled as lipid droplets cleared from the cells. Lipid-laden macrophages also did not display differences in CSF-1 stimulated macropinocytosis as observed with live-cell microscopy. Flow cytometry analysis revealed lipid laden macrophages had an increase in CD68, with decreased expression of CD11B and CD80. Differences in activation of signaling molecules highlight cellular functions affected by lipid droplets that can be targeted to prevent the proliferation of macrophages in plaques and promote plaque clearance