Engineering Geology of Western United States Urban Centers: Los Angeles, California to Denver, Colorado June 27–July 7, 1989

10.1029/ft181 ◽  
1989 ◽  
Keyword(s):  
United States ◽  
Los Angeles ◽  
Engineering Geology ◽  
Western United States ◽  
Urban Centers

scholarly journals Contrasting Patterns of Genetic Diversity and Population Structure of Armillaria mellea sensu stricto in the Eastern and Western United States

2010 ◽  
Vol 100 (7) ◽  
pp. 708-718 ◽  
Author(s):  
Kendra Baumgartner ◽  
Renaud Travadon ◽  
Johann Bruhn ◽  
Sarah E. Bergemann
Keyword(s):  
United States ◽  
Genetic Diversity ◽  
Population Structure ◽  
Los Angeles ◽  
The United States ◽  
Sensu Stricto ◽  
Western United States ◽  
Eastern United States ◽  
Armillaria Mellea ◽  
Genetic Pools

Armillaria mellea infects hundreds of plant species in natural and managed ecosystems throughout the Northern hemisphere. Previously reported nuclear genetic divergence between eastern and western U.S. isolates is consistent with the disjunct range of A. mellea in North America, which is restricted mainly to both coasts of the United States. We investigated patterns of population structure and genetic diversity of the eastern (northern and southern Appalachians, Ozarks, and western Great Lakes) and western (Berkeley, Los Angeles, St. Helena, and San Jose, CA) regions of the United States. In total, 156 diploid isolates were genotyped using 12 microsatellite loci. Absence of genetic differentiation within either eastern subpopulations (θST = –0.002, P = 0.5 ) or western subpopulations (θST = 0.004, P = 0.3 ) suggests that spore dispersal within each region is sufficient to prevent geographic differentiation. In contrast to the western United States, our finding of more than one genetic cluster of isolates within the eastern United States (K = 3), revealed by Bayesian assignment of multilocus genotypes in STRUCTURE and confirmed by genetic multivariate analyses, suggests that eastern subpopulations are derived from multiple founder sources. The existence of amplifiable and nonamplifiable loci and contrasting patterns of genetic diversity between the two regions demonstrate that there are two geographically isolated, divergent genetic pools of A. mellea in the United States.

Wet and dry plastic deposition in the western United States

2021 ◽  
Author(s):  
Janice Brahney ◽  
Margaret Hallerud ◽  
Eric Heim ◽  
Maura Hahnenberger ◽  
Suja Sukumaran
Keyword(s):  
United States ◽  
High Resolution ◽  
Wet Deposition ◽  
Life Histories ◽  
Western United States ◽  
Temporal Data ◽  
Urban Centers ◽  
Conservation Areas ◽  
Deposition Rates ◽  
Global Transport

<p>Eleven billion tons of plastic are projected to accumulate in the environment by 2025. Because plastics are persistent, they fragment into pieces that are susceptible to wind entrainment. Using high resolution spatial and temporal data we tested whether plastics deposited wet versus dry have unique atmospheric life histories. Further, we report on the rates and sources of deposition to remote U.S. conservation areas. We show that urban centers and resuspension from soils or water are important sources for wet deposition. In contrast, plastics deposited dry were smaller in size and rates were related to indices that suggest longer range or global transport. Deposition rates averaged 132 plastics m<sup>-2</sup> day<sup>-1</sup> amounting to > 1000 tons of plastic deposition to western U.S. protected lands annually.</p>

scholarly journals Model evaluation of NO<sub>3</sub> secondary organic aerosol (SOA) source and heterogeneous organic aerosol (OA) sink in the Western United States

2012 ◽  
Vol 12 (2) ◽  
pp. 5189-5223 ◽  
Author(s):  
J. L. Fry ◽  
K. Sackinger
Keyword(s):  
United States ◽  
Secondary Organic Aerosol ◽  
Organic Aerosol ◽  
Chemical Mechanism ◽  
Western United States ◽  
Urban Centers ◽  
Aerosol Composition ◽  
Organic Gases ◽  
Source And Sink ◽  
Loss Rates

Abstract. The relative importance of NO3-initiated source and heterogeneous sink of organic aerosol in the Western United States is investigated using the WRF/Chem regional weather and chemistry model. The model is run for the four individual months, representing the four seasons, of January, May, August, and October, to produce hourly spatial maps of surface concentrations of NO3, organic aerosol (OA), and reactive organic gases (ROG, a sum of alkene species tracked in the lumped chemical mechanism employed). These "baseline" simulations are used in conjunction with literature data on secondary organic aerosol (SOA) mass yields, average organic aerosol composition, and reactive uptake coefficients for NO3 on organic surfaces to predict SOA source and OA heterogeneous loss rates due to reactions initiated by NO3. We find both source and sink rates maximized downwind of urban centers, therefore with a varying location that depends on wind direction. Both source and sink terms are maximum in summer, and SOA source dominates over OA loss by approximately three orders of magnitude, with large day-to-day variability. The NO3 source of SOA is found to be atmospherically significant (peak production rates of 0.4–3.0 μg kg−1 h−1), while the heterogeneous sink of OA via NO3 surface reactions (peak loss rates of 0.11–2.3 × 10−3 μg kg−1 h−1) is likely too small to significantly impact the atmospheric lifetime of either organic aerosol or oxidized nitrogen (NOy).

scholarly journals Model investigation of NO<sub>3</sub> secondary organic aerosol (SOA) source and heterogeneous organic aerosol (OA) sink in the western United States

2012 ◽  
Vol 12 (18) ◽  
pp. 8797-8811 ◽  
Author(s):  
J. L. Fry ◽  
K. Sackinger
Keyword(s):  
United States ◽  
Secondary Organic Aerosol ◽  
Organic Aerosol ◽  
Chemical Mechanism ◽  
Western United States ◽  
Urban Centers ◽  
Aerosol Composition ◽  
Organic Gases ◽  
Source And Sink ◽  
Loss Rates

Abstract. The relative importance of NO3-initiated source and heterogeneous sink of organic aerosol in the western United States is investigated using the WRF/Chem regional weather and chemistry model. The model is run for the four individual months, representing the four seasons, of January, May, August, and October, to produce hourly spatial maps of surface concentrations of NO3, organic aerosol (OA), and reactive organic gases (ROG, a sum of alkene species tracked in the lumped chemical mechanism employed). These "baseline" simulations are used in conjunction with literature data on secondary organic aerosol (SOA) mass yields, average organic aerosol composition, and reactive uptake coefficients for NO3 on organic surfaces to predict SOA source and OA heterogeneous loss rates due to reactions initiated by NO3. We find both source and sink rates maximized downwind of urban centers, therefore with a varying location that depends on wind direction. Both source and sink terms are maximum in summer, and SOA source dominates over OA loss by approximately three orders of magnitude, with large day-to-day variability. The NO3 source of SOA (peak production rates of 0.4–3.0 μg kg−1 h−1) is found to be significantly larger than the heterogeneous sink of OA via NO3 surface reactions (peak loss rates of 0.5–8 × 10−4 μg kg−1 h−1).

Prevalence and Circumstances of Drug Injection at Los Angeles Shooting Galleries

1996 ◽  
Vol 42 (1) ◽  
pp. 21-35 ◽  
Author(s):  
Douglas Longshore
Keyword(s):  
United States ◽  
Los Angeles ◽  
Drug Use ◽  
Western United States ◽  
Drug Injection ◽  
Drug Injectors ◽  
Scale Of Operation ◽  
Shooting Galleries

This study estimates the prevalence of drug injection at shooting galleries in Los Angeles and describes their characteristics. Data indicate that 23% of local drug injectors went to a gallery during the year before their interview and that drug use at shooting galleries may have been underestimated in other studies. “Dirty works” are commonly shared in Los Angeles galleries, and gallery access is not limited to people who know each other. However, galleries in the eastern and western United States appear to differ in their scale of operation, that is, the number of users who visit them on a given day.

Street Vending in Los Angeles

Kids at Work ◽  
2019 ◽  
pp. 43-63
Author(s):  
Emir Estrada
Keyword(s):  
United States ◽  
New York ◽  
Los Angeles ◽  
Cultural Practices ◽  
The United States ◽  
Mexican Migration ◽  
Urban Centers ◽  
Street Vendors ◽  
Street Vending ◽  
Political Turmoil

Chapter 2 situates the study historically in the context of U.S. and Mexican migration and traces the formation of the street vending economy in urban centers in México and in U.S. cities such as Los Angeles and New York. The chapter demonstrates that street vending across the border is linked to macro structural forces and is not solely derivative of Latinx cultural practices. The chapter also highlights the historical precedent of street vending in the United States, as opposed to portraying the work as a direct cultural transplant from Latin America. The Latinx street vendors in Los Angeles immigrated to a society where street vending had been an economic strategy since the early nineteenth century. The chapter notes that as a result of both political turmoil and the rise of a foodie culture based on “authenticity,” attitudes toward street vendors are becoming more sympathetic and respectful, leading to the decriminalization of street vending across the state of California.

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