Search

Nowcasting is a term originating from economics, finance, and meteorology. It refers to the process of determining the uncertain state of the economy, markets or the weather at the current time by indirect means. In this paper, we describe a simple two‐parameter data analysis that reveals hidden order in otherwise seemingly chaotic earthquake seismicity. One of these parameters relates to a mechanism of seismic quiescence arising from the physics of strain‐hardening of the crust prior to major events. We observe an earthquake cycle associated with major earthquakes in California, similar to what has long been postulated. An estimate of the earthquake hazard revealed by this state variable time series can be optimized by the use of machine learning in the form of the Receiver Operating Characteristic skill score. The ROC skill is used here as a loss function in a supervised learning mode. Our analysis is conducted in the region of 5° × 5° in latitude‐longitude centered on Los Angeles, a region which we used in previous papers to build similar time series using more involved methods (Rundle & Donnellan, 2020, https://doi.org/10.1029/2020EA001097; Rundle, Donnellan et al., 2021, https://doi.org/10.1029/2021EA001757; Rundle, Stein et al., 2021, https://doi.org/10.1088/1361-6633/abf893). Here we show that not only does the state variable time series have forecast skill, the associated spatial probability densities have skill as well. In addition, use of the standard ROC and Precision (PPV) metrics allow probabilities of current earthquake hazard to be defined in a simple, straightforward, and rigorous way. Plain Language Summary: Earthquake nowcasting refers to the determination of hazard for major earthquakes at the present time, the recent past, and the near future. Nowcasting is an idea borrowed from economics, markets, and meteorology, where it has been frequently used. In this paper, we show that there is order hidden within chaotic earthquake seismicity using a very simple transformation of the data. Small earthquakes appear to transition from unstable stick‐slip events that produce seismic waves, to stable sliding where no seismic waves are produced. Our hypothesis is that this transition is due to a material phenomenon called strain‐hardening, that is frequently observed in laboratory rock mechanics experiments. The result is a state variable time series, computed over the last 51 years in California, that strongly resembles the long‐anticipated cycle of stress accumulation and release. Using supervised machine learning techniques, we can optimize the two‐parameter model. From that optimized model, we can rigorously calculate the probability of current hazard from major earthquakes. Extending these methods, we can also compute spatial hazard as well. The result is a new method for assessing earthquake hazard that may be useful for a variety of applications. Key Points: "Chaotic" seismicity contains hidden structure in the form of state variable time seriesStandard data science methods can be used to convert the time series to probabilitiesBoth temporal and spatial probabilities can be computed [ABSTRACT FROM AUTHOR]

The national demand for social justice, racial equality, and criminal justice reform rightfully and painfully continues to sweep the consciousness of this nation. Community colleges were founded on educational excellence, opportunity, and access and should reflect principles of equity, justice, and community. This mission calls upon us, the most egalitarian institutions, to lead by example by making structural and permanent changes to root out the ill effects of racism and bias from our classrooms, curriculum, and workplace. In this paper, we examined equity‐minded leadership, culture, and climate at the Los Angeles Community College District, the nation's largest, and their efforts to transform their institutions, guided by their Framework for Racial Equity and Social Justice. The Framework speaks to the values of the District and directs specific action steps and commitments that will allow the colleges and District to actively build anti‐racist organizational capacity and resilience and move forward towards a more socially and racially‐just academic community. [ABSTRACT FROM AUTHOR]

This paper presents a study exploring how migrants' belonging shapes their remittances among Bangladeshi migrants in Los Angeles. Based on migrants' perception, the paper recognizes the centrality of the family and origin community in migrants' remittances both in the NELM and in the transnational perspectives. It empirically investigates migrants' belonging and recognizes their membership in their parents' family, their own nuclear family, joint family including siblings with their respective families, extended family including multiple generations and a community of origin. It finds migrants' belonging simultaneously to the destination and origin countries, and also confirms the presence of 'friction' in such belonging, indicative of both cooperation and conflict in migrants' remittances allowing for explaining changes in their remittances such as remittances decay and resurgence. This study offers guideline for further empirical research on migrants' transnationalism and remittances with policy implications regarding the developmental consequences of remittances. [ABSTRACT FROM AUTHOR]

The 1972 paper by Professor Jack McKee of the California Institute of Technology, consulting engineer Finley Laverty and Raymond Hertzel of the California Regional Water Quality Control Board‐Los Angeles (McKee et al., 1972) was an early, important contribution to the understanding of groundwater contamination with organic liquids and to the integrated use of field, laboratory, and modeling studies to develop remediation approaches. The work presented in the paper was ahead of the curve and helped provide the foundation for the intense research, development, and education in investigation and remediation of groundwater contamination problems that began around 1980 and lasted for two decades. Reading the paper in the current context of more than 40 years of research and field experience provides perspective on how little was known in 1972 about groundwater contamination and how to address it, and how well‐formulated and forward‐looking was the work of McKee et al. Practitioner points: McKee et al. (1972) was an early, important contribution to the understanding of groundwater contamination with organic liquids and to the integrated use of field, laboratory and modeling studies to develop remediation approaches.McKee et al. present the results of site investigation and remediation planning studies for a large‐scale groundwater contamination site in the Los Angeles‐Glendale, California area.Four specific remediation goals were established, and a comprehensive program of site investigation, research, and modeling was developed to support the achievement of the remediation goals.The comprehensive site investigation and remedial planning involving field, laboratory, and modeling studies described by McKee et al. was a forerunner of what came into standard contaminated site remediation practice in the 1980s and 1990s. [ABSTRACT FROM AUTHOR]

Scholarship and advocacy on mobility justice needs to attend carefully to how presumptions about mobile embodiment are reproduced. This paper critically assesses some of the presumptions about the mobile subject within cycling interventions that focus on behaviour and infrastructural change. Bringing material and Black feminist theory together with ethnographic fieldwork on urban cycling in Los Angeles in 2014–2015, I suggest mobile subjectivity can be understood through the process of enfleshment, rather than centring on individualised cycling embodiment. Imagined through the cycling lungs, enfleshment allows for a mobile subjectivity that is inherently exposed in highly uneven ways; configured through matter and meaning; and a materialisation of relations of power distributed across space and time. Thinking with enfleshment contributes to cycling advocacy, mobility justice and geographical theory on the body by shifting how mobile subjects are understood and how difference, justice and the politics of the street are imagined and practised. [ABSTRACT FROM AUTHOR]

This paper presents the Evolvability Analysis Framework (EAF), a new perspective on evaluating complex infrastructure systems. EAF enables decision makers to explore alternative transition paths, thus providing several multi‐step options to achieve a desired end state. These multi‐step transition paths can be particularly valuable when they mitigate the impact of system degradation during the deployment of new capabilities. Additionally, EAF is formulated in a manner that empowers decision makers to apply decision variables, such as a cost cap or an equity metric, which are increasingly relevant to modern decision‐making. To demonstrate the method and its value, we apply the EAF to a case study inspired by Los Angeles' Vision 2028. We identify 26 transition paths across different performance dimensions. We model the cost and performance of each transition pathway and compare them using multiple measures, including traditional benefit‐cost metrics and differential impacts on different stakeholder groups. Our results show that multi‐step paths outperform single‐step transitions to an end state ("big bang" approaches) in most scenarios. Multi‐step paths also provide valuable alternatives when particular stakeholders value non‐cost metrics. [ABSTRACT FROM AUTHOR]

A growing constellation of satellites is providing near‐global coverage of column‐averaged CO2 observations. Launched in 2019, NASA's OCO‐3 instrument is set to provide XCO2 observations at a high spatial and temporal resolution for regional domains (100 × 100 km). The atmospheric column version of the Stochastic Time‐Inverted Lagrangian Transport (X‐STILT) model is an established method of determining the influence of upwind sources on column measurements of the atmosphere, providing a means of analysis for current OCO‐3 observations and future space‐based column‐observing missions. However, OCO‐3 is expected to provide hundreds of soundings per targeted observation, straining this already computationally intensive technique. This work proposes a novel scheme to be used with the X‐STILT model to generate upwind influence footprints with less computational expense. The method uses X‐STILT generated influence footprints from a key subset of OCO‐3 soundings. A nonlinear weighted averaging is applied to these footprints to construct additional footprints for the remaining soundings. The effects of subset selection, meteorological data, and topography are investigated for two test sites: Los Angeles, California, and Salt Lake City, Utah. The computational time required to model the source sensitivities for OCO‐3 interpretation was reduced by 62% and 78% with errors smaller than other previously acknowledged uncertainties in the modeling system (OCO‐3 retrieval error, atmospheric transport error, prior emissions error, etc.). Limitations and future applications for future CO2 missions are also discussed. Plain Language Summary: Several satellites are providing near‐global observations of Earth's atmospheric carbon dioxide (CO2). One example is NASA's new OCO‐3 instrument which is set to provide spatially dense CO2 measurements over targeted areas. Measurements may contain signals of emissions from cities and power plants. One method of finding the source(s) of observed CO2 is using a Lagrangian particle dispersion model such as X‐STILT. This model takes OCO‐3 measurements and runs atmospheric transport backwards in time to trace out the sources affecting these measurements. However, OCO‐3 and future satellite missions will yield many measurements, significantly increasing the computational cost for X‐STILT and other similar models. This paper presents an algorithm that will reduce the computational effort for X‐STILT by tracing the sources of only a subset of OCO‐3 measurements and then infers (interpolates) the rest. The following two questions are addressed: (1) How many OCO‐3 measurements does X‐STILT need for the interpolations to be accurate? (2) How do meteorology and topography affect the accuracy of the interpolations? Applying the algorithm on simulated OCO‐3 data at two test cities—Los Angeles and Salt Lake City—the time required to elucidate the CO2 sources was reduced by 62% and 78%, respectively. Key Points: Determining sources of spatially dense XCO2 observations with LPDM techniques can become time intensive and strain computational resourcesPresented in this work is an interpolation scheme that eases the computational burden of spatially dense XCO2 source determination studiesEvaluating the efficiency of this interpolation scheme revealed reductions of >50% in computational time at two testing locations [ABSTRACT FROM AUTHOR]

Legislation in the State of California mandates reductions in emissions of short‐lived climate pollutants of 40% from 2013 levels by 2030 for CH4. Identification of the sector(s) responsible for these emissions and their temporal and spatial variability is a key step in achieving these goals. Here, we determine the emissions of CH4 in Los Angeles from 2011–2017 using a mountaintop remote sensing mapping spectrometer. We show that the pattern of CH4 emissions contains both seasonal and nonseasonal contributions. We find that the seasonal component peaks in the winter and is correlated (R2 = 0.58) with utility natural gas consumption from the residential and commercial sectors and not from the industrial and gas‐fired power plant sectors. The nonseasonal component is (22.9 ± 1.4) Gg CH4/month. If the seasonal correlation is causal, about (1.4 ± 0.1)% of the commercial and residential natural gas consumption in Los Angeles is released into the atmosphere. Plain Language Summary: CH4 is a desirable target for greenhouse gas emission reductions because emission controls will have a rapid impact on radiative forcing. However, its emission budget is highly uncertain and poorly quantified. This paper reports new results from a novel mountaintop remote sensing spectrometer overlooking the Los Angeles basin. The study shows that the megacity's methane emissions are strongly correlated with the consumption of natural gas by residential and commercial consumers, with a leakage rate of (1.4 ± 0.1)%, while the nonseasonal component is (22.9 ± 1.4) Gg CH4/month. By identifying a clear relationship between CH4 emissions and natural gas consumption, our results provide strong constraints on the pathways for fugitive CH4 emissions from the natural gas distribution system in Los Angeles. Key Points: A mountaintop remote sensing spectrometer is used to derive the time series and spatial pattern of methane emissions in LA basinThe methane emissions in the LA basin are strongly correlated with the consumption of natural gas by residential and commercial consumersAbout (1.4 ± 0.1)% of the residential and commercial natural gas consumption in LA is released into the atmosphere [ABSTRACT FROM AUTHOR]

This paper asks the question – who moves into what kinds of neighbourhoods and what kind of residential sorting is occurring in the ethnically diverse metropolitan region of Los Angeles. The study examines residential selections across a typology of neighbourhood types in the Los Angeles metropolitan region using residential mobility data from the Los Angeles Family and Neighborhood Survey (LAFANS). Similar to recent work in the UK and Canadian contexts, ethnic groups demonstrate moderately strong relationships between their socio‐economic statuses and their neighbourhood contexts. Both behaviour, that is, actual moves and preferences, are consistent with a tendency to increased mixing and declining segregation in the residential mosaic. In particular, the expressed residential preferences and the choices of these households provide an explanatory context for the overall decline in segregation. [ABSTRACT FROM AUTHOR]

This paper focuses on the process of institutional change at the leading ports of the United States: Los Angeles and Long Beach. In order to do so, it makes use of the structure of provision-approach and the concept of regime politics which allows for a systematic analysis and comparison. Key questions are: how are both ports institutionally structured? How do they evolve in relation to each other? And what is the role of agency in this process? The paper reveals how both ports remain institutionally different in spite of competition. This persistent institutional diversity can be explained by that fact that institutions represent territorially rooted structures of power in which competitive performance will not always be the decisive interest. [ABSTRACT FROM AUTHOR]

The role of diuretic renography has become central in cases of upper tract dilatation, and in the first paper in this section the difficulties in interpreting results in asymptomatic congenital hydronephrosis are examined. These difficulties and controversies exist despite the presence of guidelines and consensus protocols, probably because renography procedures differ among centres. The authors found that there is a need for renography to be standardized for the optimum value to be obtained from the procedure.There are three papers from Los Angeles which attempt to standardize the measurement of bladder compliance, from both the theoretical and clinical perspective, and which assess the detrusor pressure rise of a normal bladder when filled to capacity.To discuss the main steps of renographic technique and underline some pitfalls related to the acquisition, processing and interpretation of diuretic renography, an important method for guiding the management of asymptomatic congenital hydronephrosis.Despite guidelines and consensus protocols, renographic procedures differ among centres, causing difficulties in comparison and controversy in the interpretation of results. Thus we comprehensively assessed published papers on the subject of diuretic renography.Differential renal function (DRF) is a robust measure provided there is adequate background subtraction. Pitfalls are related to the drawing of regions of interest, particularly in infants, to estimating the interval during which DRF is calculated, and to an adequate signal-to-noise ratio. There is no definition of a‘significant’ reduction in DRF. The classical variables of the diuretic renogram may not allow an estimate of the best drainage. Poor pelvic emptying may be apparent because the bladder is full and because the effect of gravity on drainage is incomplete. Estimating the drainage as residual activity rather than any parameter on the slope might be more adequate, especially if the time of frusemide administration is changed. Renal function and pelvic volume can influence the quality of drainage. Drainage may be better estimated using new tools.Provided the investigation is standardized and potential pitfalls accounted for, the diuretic renogram provides valuable and reproducible quantitative information on DRF and drainage. [ABSTRACT FROM AUTHOR]

This paper presents a theory of the role of culture in collaborative policy networks. It builds on the literature that analyzes the factors related to the formation, maintenance, and dissolution of collaborative arrangements by demonstrating the importance of hitherto undertheorized cultural factors. Cultural theory indicates that actors with different cultural viewpoints have distinct and predictable biases in terms of their expectations of collaboration and their preferences concerning how collaborative policy networks are structured. These biases, in turn, shape how collaborative partners are chosen and how collaborative relationships are maintained over time. The theory is illustrated with a case study of the rise and dissolution of a coalition within a housing policy network in Los Angeles. The case illustrates that cultural differences can impede collaboration even when organizations share similar policy goals. [ABSTRACT FROM AUTHOR]

The article focuses on the water environment research paper titled "Characteristics of Highway Stormwater Runoff," by Y. Han, S. Lau, M. Kayhanian, and M. K. Stenstrom. The paper examined a large amount of highway stormwater runoff from different traffic sites in Los Angeles, California. It mentioned that pavement degradation is one of the main cause of pollutants in highway stormwater runoff wherein pavement type affect the stormwater's pH, alkalinity, and organic and inorganic solids. It also showed the difference between chlorine and chloride through water analysis.

Submitted to Special Issue on ' Computational Approaches to Analysis of Emotion in Text' Guest editors: Diana Inkpen and Carlo Strapparava Initial publication: NAACL-HLT 2010 Workshop on Computational Approaches to Analysis and Generation of Emotion in Text, June 5, 2010, Los Angeles, CA Though data-driven in nature, emotion analysis based on latent semantic analysis still relies on some measure of expert knowledge to isolate the emotional keywords or keysets necessary to the construction of affective categories. This makes it vulnerable to any discrepancy between the ensuing taxonomy of affective states and the underlying domain of discourse. This paper proposes a more general strategy which leverages two separate semantic levels: one that encapsulates the foundations of the domain considered, and one that specifically accounts for the overall affective fabric of the language. Exposing the emergent relationship between these two levels advantageously informs the emotion classification process. Empirical evidence suggests that this approach is promising for automatic emotion analysis in text. This bodes well for its deployability in a variety of applications, such as sentiment prediction. [ABSTRACT FROM AUTHOR]

This paper traces how Los Angeles peace activists tried to make visible the grave domestic effects of Cold War militarization. Women Strike for Peace went beyond a focus on the productive relations between the state, military and industry captured by the term 'military-industrial complex' to analyze how reproductive spaces were part of this complex. In opposing war, they challenged what I am calling militarized domesticities: how war-making shapes the 'home front' and home as the spaces national security states claim to protect. I build on feminist antiracist intersectionality theories to situate the military-industrial complex per se within broader processes of the militarization of society and daily life. The questions become how do gendered processes of militarization-that work in conjunction with relations of white privilege-produce and connect differently situated 'private' spaces or home places? How might strategies for dismantling the military-industrial complex emerge from the contradictions of these processes? [ABSTRACT FROM AUTHOR]

Aims In order to increase the number of investigative teams and sites conducting research on pharmacological treatments for methamphetamine use disorders, the National Institute on Drug Abuse (NIDA) established an infrastructure of clinical sites in areas where methamphetamine addiction is prevalent. This multi-site infrastructure would serve to run multiple Phases II and III protocols effectively and expeditiously. Methods NIDA collaborated with investigators from the University of California at Los Angeles (UCLA) to set up the Methamphetamine Clinical Trials Group (MCTG). This paper describes the development process, as well as data from a test trial to assess the capability of research-naive sites to recruit research participants and conduct study procedures according to research protocol. Subsequent trials are also described. Results A total of 151 candidates signed consent; 65 individuals were enrolled and 35 (53.8%) completed the 12 weeks' behavioral trial. Self-reported substance use report (SUR) showed comparable use of methamphetamine across sites with the individual site means ranging from 59% (site 5) to 80% (site 3). Drug use as measured by urinalysis was greatly reduced at week 13 compared to the baseline measure; the average rate of methamphetamine-free urine samples across all participants in sites at week 13 was 53%. The highest percentage of methamphetamine-free samples was 85% at site 5; the lowest was at site 1 (40%). Addiction severity index (ASI) composite scores at baseline and protocol completion for all participants demonstrated improvement in all categories over time, except for the medical composite score. The largest composite score reduction in baseline-protocol completion was in the drug domain (0.23 versus 0.15). The changes in the ASI scores from baseline to week 13 were consistent across all five sites. Conclusions Outcomes of the behavioral trial indicated that the MCTG recruited well; collected study data accurately and reliably; and created a vehicle that can assess promising pharmacotherapies for methamphetamine addiction treatment medications. The MCTG strategy appears to be a feasible approach to increase NIDA's capacity to conduct clinical trials to evaluate potential pharmacotherapies for methamphetamine addiction. [ABSTRACT FROM AUTHOR]

Although hyperdiverse groups like terrestrial arthropods are almost certainly severely impacted by habitat fragmentation and destruction, few studies have formally documented such effects. In this paper, we summarize the results of a multifaceted research approach to assess the magnitude and importance of anthropogenic population extinction on the narrowly endemic trapdoor spider genus Apomastus. We used geographical information systems modeling to reconstruct the likely historical distribution of Apomastus, and used molecular phylogeographic data to discern population genetic structure and detect genetic signatures of population extinction. In combination, these complementary lines of inference support direct observations of population extinction, and lead us to conclude that population extinction via urbanization has played an important role in defining the modern-day distribution of Apomastus species. This population loss implies coincident loss of genetic and adaptive diversity within this genus, and more generally, suggests a loss of ground-dwelling arthropod population diversity throughout the Los Angeles Basin. Strategies for minimizing this loss are proposed. [ABSTRACT FROM AUTHOR]

This paper explores why young people leave home and become homeless. Drawing on life history interviews conducted with 50 homeless youth in Los Angeles, explanations provided by participants for becoming homelessness and. how they understand their experiences are presented. In professional discourses, homeless young people are often portrayed as victims of physical abuse and emotional neglect. Although participants' narratives reveal that abuse and neglect play a central role in their decisions to leave home, many maintain a sense of agency in the recounting of how they became homeless. The importance of service providers recognizing young people's agency is discussed. [ABSTRACT FROM AUTHOR]

New York, Los Angeles, and Miami are primate immigrant centers within the U.S. metropolitan system, attracting new immigrant arrivals as well as serving as focal points for internal migrants. Using the segmented assimilation framework as a foundation, this paper emphasizes the role of geography and migration within the assimilation process. Focusing upon selected origin groups, migrant selectivity and the determinants of migration are evaluated and compared, highlighting the differential role of primate centers. While the New York and Miami metropolitan centers clearly dominate Dominican and Cuban migration systems respectively, the role of primate centers is less clear among other national origin groups. [ABSTRACT FROM AUTHOR]

This paper describes the transplantation of psychoanalysis from Europe to Los Angeles and the similarities and differences in followers, cultural attitudes, institutional organization, and patient symptoms. Psychoanalysis in both places attracted psychiatrists, psychologists, social workers, artists, writers, and movie people, all committed to “modernism” and cultural change. But special American conditions created greater institutional rigidity, medicalization, and a more diffuse patient symptomatology centered on the maternal relationship. Such conditions also fostered bitter disputes over modifications of psychoanalytic theory and practice which have only recently become less acute as the status of psychoanalysis has declined in America. © 2001 John Wiley & Sons, Inc. [ABSTRACT FROM AUTHOR]

This article explores how the events that saw the death of film producer Paul Bern in the Labor Day weekend of 1932 came to be understood by various individuals in differing ways. The death of Bern, Hollywood producer and the husband of film actress Jean Harlow, was actively negotiated by both participants and spectators. Toward this end, this article will analyze a variety of texts, as material culture, texts, that provide a masking ideology, hiding or misrepresenting the internal contradictions. The positioning of this essay, of necessity, rejects any consideration of what really happened to Bern. For though the writers of the various texts discussed could easily have examined police and other records, their chief interest lay in reinforcing an image of Bern and the events surrounding his death that best suited their ideological constraints. The circumstances recounted in this paper are distant memories for the participants, most of whom penned their memories decades after that infamous Labor Day weekend. Paul Bern as crime statistic was less portentous that Paul Bern as icon of Hollywood's Depression-era social problems. For when the specter of sexuality was cast over the tragedy of his death, his life came to be interpreted as either his inability to participate in Harlow's world of frank sexuality, or his depraved bestiality in the face of her innate innocence.

Information on several papers discussed at the Mediterranean Ecosystems (MEDECOS) XII conference on fire as an evolutionary pressure shaping plant traits held in Los Angeles, California on September 2011 is presented. Topics include ecological science, role of fire in biome distribution, and micro-evolutionary approach to show the natural selection driven by fire. The conference features several presenters including William Bond, Susana Gómez-González, and Juli G. Pausas.

In this paper we summarize an integrated, operational model of losses due to earthquake impacts on transportation and industrial capacity, and how these losses affect the metropolitan economy. The procedure advances the information provided by transportation and activity system analysis techniques in ways that help capture the most important ecomonic implications of earthquakes. Network costs and origin-destination requirements are modeled endogenously and consistently. Indirect and induced losses associated with direct impacts on transportation and industrial capacity are distributed across zones and ecomonic sectors. Preliminary results are summarized for a magnitude 7.1 earthquake on the Elysian Park blind thrust fault in Los Angeles. [ABSTRACT FROM AUTHOR]

This paper describes portfolio development by pre-service art teachers in a secondary teaching programme at California State University, Los Angeles, USA. A portfolio reflects knowledge, skills, and beliefs about teaching in general and teaching art specifically. It displays one's learning experiences as they are collected, organized, and refined to provide a critical framework and rich portrayal of one's best work. The article addresses the questions of what a portfolio in art education is, what its goals are, how one creates a portfolio, how one assesses portfolios once they are developed, what the issues and challenges surrounding the use of portfolios as assessment tools are, and finally, some likely future developments of portfolio assessment in teacher education. [ABSTRACT FROM AUTHOR]