Investigation of an empirical methodology for linking value of time with census tract median income

This research examines a new methodology for prospectively estimating the willingness of travelers to use a toll road by combining travel time saved with the income of the prospective customer base. The purpose of the research is to facilitate network level planning by allowing some reasonable predictions of acceptable toll rates from readily available data and estimation techniques. Methods of estimating user benefit resulted in simulated distributions of value of user time. Values of time are linked to census tract income data for the user population to produce value of time as a percentage of income as an indicator. As relevant literature acknowledges the tendency toward increased toll road usage at higher income levels, it is hypothesized that linking estimates of value of time directly to household income would produce a more useful indicator of the travel market than do conventional indicators. Techniques for prospectively estimating the travelshed of a toll road are compared with the actual travelshed, as reflected in user home census tracts, as a means of evaluating the efficacy of those techniques in estimating the market area of a prospective toll road. Results show that considering value of time as a percentage of census tract median income provides an improved portrayal of the toll road market, as usage of the toll road increases with increasing income. Using census tract median income as the income parameter has shortcomings, in that it produces anomalous results at very low population levels. Of the two methods of estimating the travelshed, the visual estimation approach was not satisfactory, leaving the analyst to use select link analyses instead

Aerosol Optical Hygroscopicity Measurements during the 2010 CARES Campaign

Measurements of the effect of water uptake on particulate light extinction or scattering made at two locations during the 2010 CARES study around Sacramento, CA are reported. The observed influence of water uptake, characterized through the dimensionless optical hygroscopicity parameter γ, is compared with calculations constrained by observed particle size distributions and size-dependent particle composition. A closure assessment has been carried out that allowed for determination of the average hygroscopic growth factors (GF) at 85% relative humidity and the dimensionless hygroscopicity parameter κ for oxygenated organic aerosol (OA) and for supermicron particles, yielding κ = 0.1–0.15 and 0.9–1.0, respectively. The derived range of oxygenated OA κ values are in line with previous observations. The relatively large values for supermicron particles is consistent with substantial contributions of sea salt-containing particles in this size range. Analysis of time-dependent variations in the supermicron particle hygroscopicity suggest that atmospheric processing, specifically chloride displacement by nitrate and the accumulation of secondary organics on supermicron particles, can lead to substantial depression of the observed GF

Aerosol optical hygroscopicity measurements during the 2010 CARES campaign

Measurements of the effect of water uptake on particulate light extinction or scattering made at two locations during the 2010 Carbonaceous Aerosols and Radiative Effects Study (CARES) study around Sacramento, CA are reported. The observed influence of water uptake, characterized through the dimensionless optical hygroscopicity parameter γ, is compared with calculations constrained by observed particle size distributions and size-dependent particle composition. A closure assessment has been carried out that allowed for determination of the average hygroscopic growth factors (GFs) at 85% relative humidity and the dimensionless hygroscopicity parameter κ for oxygenated organic aerosol (OA) and for supermicron particles (defined here as particles with aerodynamic diameters between 1 and 2.5 microns), yielding κ = 0.1–0.15 and 0.9–1.0, respectively. The derived range of oxygenated OA κ values are in line with previous observations. The relatively large values for supermicron particles is consistent with substantial contributions of sea-salt-containing particles in this size range. Analysis of time-dependent variations in the supermicron particle hygroscopicity suggest that atmospheric processing, specifically chloride displacement by nitrate and the accumulation of secondary organics on supermicron particles, can lead to substantial depression of the observed GF

Overview of the 2010 Carbonaceous Aerosols and Radiative Effects Study (CARES)

Substantial uncertainties still exist in the scientific understanding of the possible interactions between urban and natural (biogenic) emissions in the production and transformation of atmospheric aerosol and the resulting impact on climate change. The US Department of Energy (DOE) Atmospheric Radiation Measurement (ARM) program's Carbonaceous Aerosol and Radiative Effects Study (CARES) carried out in June 2010 in Central Valley, California, was a comprehensive effort designed to improve this understanding. The primary objective of the field study was to investigate the evolution of secondary organic and black carbon aerosols and their climate-related properties in the Sacramento urban plume as it was routinely transported into the forested Sierra Nevada foothills area. Urban aerosols and trace gases experienced significant physical and chemical transformations as they mixed with the reactive biogenic hydrocarbons emitted from the forest. Two heavily-instrumented ground sites – one within the Sacramento urban area and another about 40 km to the northeast in the foothills area – were set up to characterize the evolution of meteorological variables, trace gases, aerosol precursors, aerosol size, composition, and climate-related properties in freshly polluted and "aged" urban air. On selected days, the DOE G-1 aircraft was deployed to make similar measurements upwind and across the evolving Sacramento plume in the morning and again in the afternoon. The NASA B-200 aircraft, carrying remote sensing instruments, was also deployed to characterize the vertical and horizontal distribution of aerosols and aerosol optical properties within and around the plume. This overview provides: (a) the scientific background and motivation for the study, (b) the operational and logistical information pertinent to the execution of the study, (c) an overview of key observations and initial findings from the aircraft and ground-based sampling platforms, and (d) a roadmap of planned data analyses and focused modeling efforts that will facilitate the integration of new knowledge into improved representations of key aerosol processes and properties in climate models.United States. Dept. of Energy. Atmospheric System Research Program (Contract DE-AC06-76RLO 1830)United States. National Oceanic and Atmospheric AdministrationUnited States. National Aeronautics and Space Administration. HQ Science Mission Directorate Radiation Sciences ProgramUnited States. National Aeronautics and Space Administration. CALIPSO ProgramUnited States. Dept. of Energy. Atmospheric Radiation Measurement Program (Interagency Agreement No. DE-AI02-05ER63985

Measured in-situ mass absorption spectra for nine forms of highly-absorbing carbonaceous aerosol

Mass absorption coefficient spectra were measured between λ = 500 nm and 840 nm for nine forms of highly-absorbing carbonaceous aerosol: five samples generated from gas-, liquid- and solid-fueled flames; spark-discharge fullerene soot; graphene and reduced graphene oxide (rGO) crumpled nanosheets; and fullerene (C_(60)) assemblies. Aerosol absorption spectra were measured for size- and mass-selected particles and found to be dependent on fuel type and formative conditions. Flame-generated particles had morphologies consistent with freshly emitted black carbon (BC) with mass absorption coefficients (MAC) ranging between 3.8 m^2 g^(−1) and 8.6 m^2 g^(−1) at λ = 550 nm. Absorption Ångström exponents (AAE) – i.e. MAC spectral dependence – ranged between 1.0 and 1.3 for flame-generated particles and up to 7.5 for C_(60). The dependence of MAC and AAE on mobility diameter and particle morphology was also investigated. Lastly, the current data were compared to all previously published MAC measurements of highly-absorbing carbonaceous aerosol

Investigation of an empirical methodology for linking value of time with census tract median income

This research examines a new methodology for prospectively estimating the willingness of travelers to use a toll road by combining travel time saved with the income of the prospective customer base. The purpose of the research is to facilitate network level planning by allowing some reasonable predictions of acceptable toll rates from readily available data and estimation techniques. Methods of estimating user benefit resulted in simulated distributions of value of user time. Values of time are linked to census tract income data for the user population to produce value of time as a percentage of income as an indicator. As relevant literature acknowledges the tendency toward increased toll road usage at higher income levels, it is hypothesized that linking estimates of value of time directly to household income would produce a more useful indicator of the travel market than do conventional indicators. Techniques for prospectively estimating the travelshed of a toll road are compared with the actual travelshed, as reflected in user home census tracts, as a means of evaluating the efficacy of those techniques in estimating the market area of a prospective toll road. Results show that considering value of time as a percentage of census tract median income provides an improved portrayal of the toll road market, as usage of the toll road increases with increasing income. Using census tract median income as the income parameter has shortcomings, in that it produces anomalous results at very low population levels. Of the two methods of estimating the travelshed, the visual estimation approach was not satisfactory, leaving the analyst to use select link analyses instead

Predicting first-time freshman persistence at California State University, Bakersfield: Exploring a new model

Institutions of higher education invest a significant amount of resources in recruiting, processing, and advising new students. When students leave the institution prior to graduation, the university loses considerable revenues. Therefore, it is important for colleges and universities to refine their student recruitment and retention strategies to avoid forgone revenues by predicting which students are likely to need particular types of support services (DeBerard et al, 2004). Current models of prediction utilize extensive surveys that are impractical to administer each term, and they do not adequately identify the broad range of student persistence categories needed in order to gain a greater understanding of persistence behavior (Davidson, 2005; Porter, 2000; Tinto, 1975). This study created a linear discriminant function to predict a broad range of persistence levels of first-time freshmen students at California State University, Bakersfield (CSUB), by identifying pre-enrollment and early enrollment student variables that existed within the database of the University. This information may be used to develop support service strategies to better assist incoming students predicted to have a greater probability of not persisting

Racial Disparities in Health Services Access Amongst Children in the U.S. Child Welfare System: Future Directions to Challenge the Status Quo Based on a Systematic Review

The project pertains to a scoping examining the racial disparities in health services access and healthcare utilization amongst children in the U.S child welfare system