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Traffic state estimation (TSE), which reconstructs the traffic variables (e.g., speed, flow) on road segments using partially observed data, plays an essential role in intelligent transportation systems. Generally, traffic estimation problems can be divided into two categories: model-driven approaches and data-driven approaches. The model-driven method is commonly used to solve TSE efficiently and calibrate the parameters of these models. The data-driven method requires a large amount of historical observed traffic data in order to improve performance accurately. In order to combine the advantages of model-driven and data-driven methods, this paper proposed a hybrid framework incorporating the traffic flow model into deep learning (TFMDL) modeling that contains both model-driven and data-driven components. This paper focuses on highway TSE with observed data from loop detectors. We build a hybrid cost function to adjust the weights of model-driven and data-driven proportions. We then evaluate the proposed framework using the open-access performance measurement system (PMS) dataset on a corridor of US I-405 in Los Angeles, California. The experimental results show the advantages of the proposed TFMDL approach in performing better than several benchmark models in terms of estimation accuracy and data efficiency. [ABSTRACT FROM AUTHOR]

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]

From the onset of the COVID‐19 pandemic, policymakers and news reports warned that restrictions on individual mobility and commercial activity could lead to a surge in domestic violence (DV). Some initial studies found evidence of greater DV incidence during the pandemic, but findings were inconsistent across locations and DV measures. This paper focuses on a single major city, Los Angeles (LA), to study the impact of the initial pandemic shutdown. We use three DV measures from police data (911 calls, crime incidents and arrests) as well as two measures from non‐police administrative sources (the county DV hotline and hospital records). We find an increase in DV calls to the police and calls to the hotline. However, we find that DV crimes recorded by police and hospital visits by female assault (and DV) victims decreased significantly, suggesting that the increase in calls came from higher reporting rates. The decrease in DV crimes is not attributable to reductions in policing intensity, as the arrest rate for DV crimes was higher during the shutdown. We conclude that the initial LA shutdown increased the rates at which people contacted authorities about DV, but decreased the overall incidence of physical DV crimes in the population. [ABSTRACT FROM AUTHOR]

This paper discusses the nonlinear dynamic seismic response of a 14‐story reinforced concrete core wall building designed with the prescriptive requirements of the 2019 California Building Code for a near‐fault site in Los Angeles, California, simulated with a detailed nonlinear analysis of the complete structure and subjected to an ensemble of three‐component ground motion input. The study follows up on a recently published work by the authors, which examined the response of the specific building to static lateral loads. The nonlinear model of the building was developed in the software FE‐Multiphys using a shell‐element implementation of the beam–truss model (BTM). The BTM has been extensively validated through prior studies for planar, flanged, and coupled walls under static and dynamic loading. The building model was subjected to an ensemble of ground motions scaled at the design and risk‐targeted maximum considered earthquake levels. The vertical ground motion component and the out‐of‐plane shear degradation of wall piers were included in the simulations. The analyses elucidate the profound effect of nonlinear flexure–shear interaction and of the multidirectional behavior of the flanged coupled core wall on the evolution and localization of damage and on residual deformations. The coupling behavior between the core wall, the slabs, and the columns is also analyzed, and the importance of modeling the nonlinear behavior of all slabs for the residual damage evaluation is demonstrated. The aim of this study is to improve the understanding of issues arising from prescriptive design requirements as well as of issues associated with limitations of standard nonlinear seismic analysis. [ABSTRACT FROM AUTHOR]

This paper presents a comprehensive framework for life‐cycle carbon emission assessment of steel frame structures in seismic zones, with a particular focus on emerging self‐centering steel structures with reduced residual deformation and enhanced seismic resilience. The proposed framework is illustrated through a life‐cycle embodied carbon (EC) emission study on an office building located at Los Angeles, USA. Different structural bracing systems are considered for comparison, namely, conventional concentrically braced frame (CBF), bucking‐restrained braced frame (BRBF), and self‐centering braced frames (SCBFs). The life cycle assessment (LCA) of EC emissions mainly involves four phases: (1) components manufacturing phase, (2) construction phase, (3) operation and maintenance phase, and (4) EC emissions related to seismic hazard. For the last stage, the engineering demand parameter (EDP) is obtained through incremental dynamic analysis (IDA), and combined with the fragility function and the seismic risk curve to obtain the expected EC emissions related to seismic hazard over the life cycle. Among other findings, the results show that: (1) In the manufacturing process, the EC emissions of the emerging SCBFs are slightly increased (by up to 1.4%) compared with the two other conventional steel frames. (2) During the construction, operation, and maintenance phases, there is no difference in the EC emissions for the different structural systems. (3) The EC emissions related to potential seismic risk are reduced by up to 65.3% when the proposed self‐centering structural system (P‐SCBF) is used. (4) Compared with the CBF, the total EC emission over a 100‐year lifespan can be reduced by up to 14.6% when the P‐SCBF is used. Due to the limited deformation capacity of braces, the EC emissions of CBF and BRBF are more sensitive to increases in the intensity measure (IM). Since a building becomes difficult to repair when the maximum residual inter‐story drift exceeds 0.5%, BRBF and CBF are more susceptible to demolition due to unacceptable residual deformation, leading to higher EC emissions. The EC reduction efficiency of the emerging steel frames become more remarkable with increasing life span. [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]

As the amplification of seismic force demands due to higher‐mode effects on tall buildings is increasingly recognized as a design challenge, a number of high‐performance systems have been proposed to limit such effects through combined base shear‐limiting and moment‐limiting dual mechanisms. To better understand the influence of these dual base systems on the overall seismic behavior of tall buildings, this paper presents a study on the seismic response of Multi‐Degree‐of‐Freedom (MDOF) systems incorporating combined base shear‐limiting and moment‐limiting mechanisms. For an MDOF system with a given initial period and base strength level, the base shear‐limiting mechanism is defined by a shear strength factor, an inelastic stiffness parameter, and an energy‐dissipation parameter, while the base moment‐limiting mechanism is defined by a moment strength factor. To determine the influence of these parameters on the overall seismic responses of MDOF structures, a comprehensive parametric study was conducted, and the results were presented and discussed in terms of base displacement and rotation demands, seismic force demand amplification at the base and along the height, peak floor acceleration, peak roof drift, and absorbed energy. The numerical modeling methodology used in the parametric study was validated against 200 small‐scale shaking table tests of a scaled MDOF specimen with a base shear and moment dual‐mechanism system and was used to model MDOF structures that are representative of tall buildings with initial periods ranging from 1.0 to 10 s and having various base‐mechanism properties. The parametric study was then conducted using an ensemble of 20 Ground Motions (GM) scaled to three code‐specified seismic hazard levels for Los Angeles, California. The results of this study can be used to facilitate the design of base shear and moment dual‐mechanism systems for mitigating higher‐mode effects and enhancing the seismic resilience of tall buildings. [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 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.

Summary: High‐rise buildings are an efficient solution to meet the housing challenges of global urbanization that is happening at an incredible pace. Code‐based seismic design philosophies are aimed at achieving collapse‐prevention under major earthquakes, implying extensive structural damage associated with important losses. A number of high‐performance systems have been investigated for enhancing the resilience of high‐rise buildings whose design is especially challenging due to higher‐mode effects even when a flexural mechanism is formed at the base of the structure. To this end, this paper proposes a new concept consisting of a three‐dimensional uncoupled rocking and shear mechanism system for high‐rise buildings where reinforced concrete (RC) core walls are used as the lateral‐force‐resisting system. The proposed system provides a dual‐mechanism at the base that independently limits both overturning moments (OTMs) and shear forces and thus more effectively mitigates higher‐mode effects. The characteristic mechanics of the proposed system are first studied through an idealized model. A physical embodiment is then designed, detailed, and validated through advanced models and extensive nonlinear dynamic analyses. A 42‐story RC core‐wall building that is located in Los Angeles and was studied as part of the PEER Tall Buildings Initiative is used as a reference structure in this study. Results confirmed that the proposed system eliminates damage at the base of the walls and minimizes the inelastic demands over the height of the building. In a general sense, the proposed concept provides a framework in which the intended dual mechanism can be implemented to a wider range of high‐rise structures. [ABSTRACT FROM AUTHOR]

Summary: This paper investigates a Fletcher‐Reeves conjugate gradient optimized multi‐reservoir echo state network (FRCG‐MESN) to identify battery state of charge (SOC). First, an echo state network with multiple reservoirs is established to estimate battery SOC by using its discharge terminal voltage and current as the inputs, and the FR conjugate gradient algorithm is explored to tune the output weights of the MESN to avoid calculating the inverse matrix. Second, an appropriate amount of Gaussian noise with zero mean is added to the training set to prevent overfitting. Finally, a battery test platform is adopted to sample the discharging data under two working conditions: the Los Angeles 92 and the urban dynamometer driving schedule. The simulation results show that the presented FRCG‐MESN method can accurately identify the battery SOC with different initial SOCs. Applying an appropriate amount of noise to the training set can prevent overfitting efficiently. [ABSTRACT FROM AUTHOR]

Announces the publication of papers of the plenary and concurrent sessions at the International Council of Nurses' 17th quadrennial congress in Los Angeles, California.

SUMMARY This paper presents the motivation and the mathematics required for the introduction of Bayesian structural reliability theory into the process of evaluating and strengthening any tall building located in the Los Angeles region. Copyright © 2013 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Studying the time interval duration between the first accident and the second accident caused by it can provide decision makers with valuable information on how to effectively deal with high-risk second accidents. This paper is aimed to explore the potential influencing factors of the interval duration between the two accidents and predict it. First, the spatiotemporal definition method is applied to identify the cascaded first accident and the second accident. Then, on the basis of using Kaiser-Meyer-Olkin (KMO) measure and Bartlett's sphere test statistics to ensure the applicability of the data to the factor analysis method, the explanatory variables that can significantly affect the interval duration are obtained through the factor analysis method. Finally, the random forest model (RF), which combines the advantages of machine learning methods, is employed to predict the duration of the interval. Traffic accident data set collected in Los Angeles city from February 2016 to June 2020 is used to validate prediction performance in this study. Bayesian method is applied to optimize the hyperparameters in the RF, while three evaluation indicators, including the Root Mean Squared Error (RMSE), Mean Squared Error (MSE), and Mean Absolute Percentage Error (MAPE), are used to estimate the prediction effect. The test results and comparative experiments confirm that RF is able to predict the interval well and has better prediction performance. This is of great significance for the prediction of the duration of the interval between one accident and the second accident. [ABSTRACT FROM AUTHOR]

This issue is the 2009 Special Issue of the journal developed by the Los Angeles Tall Buildings Design Council. The papers noted in this issue are all exceptional papers selected by the council. [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]

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]

SUMMARY This paper presents a methodology in wind design including in a scientific way the benefits of using dampers and of performing a nonlinear dynamic analysis of tall concrete buildings that are being evaluated and strengthened. It is developed for tall buildings in the Los Angeles region but is without geographic bounds. The uses of equations of structural reliability form this scientific basis. Copyright © 2013 John Wiley & Sons, Ltd. [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]

The scarcity of strong ground motion records presents a challenge for making reliable performance assessments of tall buildings whose seismic design is controlled by large‐magnitude and close‐distance earthquakes. This challenge can be addressed using broadband ground‐motion simulation methods to generate records with site‐specific characteristics of large‐magnitude events. In this paper, simulated site‐specific earthquake seismograms, developed through a related project that was organized through the Southern California Earthquake Center (SCEC) Ground Motion Simulation Validation (GMSV) Technical Activity Group, are used for nonlinear response history analyses of two archetype tall buildings for sites in San Francisco, Los Angeles, and San Bernardino. The SCEC GMSV team created the seismograms using the Broadband Platform (BBP) simulations for five site‐specific earthquake scenarios. The two buildings are evaluated using nonlinear dynamic analyses under comparable record suites selected from the simulated BBP catalog and recorded motions from the NGA‐West database. The collapse risks and structural response demands (maximum story drift ratio, peak floor acceleration, and maximum story shear) under the BBP and NGA suites are compared. In general, this study finds that use of the BBP simulations resolves concerns about estimation biases in structural response analysis which are caused by ground motion scaling, unrealistic spectral shapes, and overconservative spectral variations. While there are remaining concerns that strong coherence in some kinematic fault rupture models may lead to an overestimation of velocity pulse effects in the BBP simulations, the simulations are shown to generally yield realistic pulse‐like features of near‐fault ground motion records. [ABSTRACT FROM AUTHOR]

The aeronautical community is currently researching technology that might lead to commercial hypersonic aircraft that would cruise at Mach 5–8 in the middle or upper stratosphere and would transfer passengers from London to New York or from Los Angeles to Tokyo in just a couple of hours. Depending on the engine technology to be adopted, these aircraft will potentially release substantial amounts of water vapor and nitrogen oxides around 30–40 km altitude. We show here that the operation of a large fleet of such aircraft could potentially deplete considerable amounts of ozone in the stratosphere, which would lead to a substantial increase in biologically damaging ultraviolet radiation reaching the Earth's surface. The calculations are based on a specific emission scenario, which carries large uncertainties but can easily be scaled to account for the type of aircraft engine to be eventually adopted, improved technology to be expected, and the size and operation conditions of the future aircraft fleet. Plain Language Summary: Commercial hypersonic aircraft, if developed in the future, will be flying at Mach 5 to 8 in the middle to upper stratosphere (30 to 40 km altitude) to carry passengers in a couple of hours from London to New York or from Los Angeles to Tokyo. Depending on the adopted technology and fleet size, the powerful engines of such airplanes may release substantial amounts of water and nitrogen oxides in the stratosphere, which could potentially damage the protecting ozone layer and hence increase the level of biologically damaging ultraviolet radiation reaching the Earth surface. The paper uses an advanced global atmospheric model to assess the impact of a potential fleet of hypersonic aircraft. Key Points: Hypersonic transport (HST) releasing nitrogen oxides and water vapor have the potential to reduce the stratospheric ozone abundancePer Tg injection of nitrogen oxides, the calculated ozone depletion is larger for aircraft flying at 30 km than 40 km altitudeOzone decrease near the HST flight altitude is reduced by about a third when temperature and dynamical feedbacks are taken into account [ABSTRACT FROM AUTHOR]

Voter mobilization by unions has garnered some attention from scholars, and is seen as an important political tool. Unions often mobilize voters repeatedly across several campaigns; however, the literature treats mobilization as a singular event. This paper empirically analyzes turnout of 85,064 registered voters over 14 months at five election intervals in Los Angeles, exploring whether union-led mobilization is subject to diminishing returns across multiple elections. Results indicate that diminishing returns occur; three or more contacts are no more beneficial than one or two. Contact in recent elections is more effective than distant contact, and results differ slightly by contact type. [ABSTRACT FROM AUTHOR]

Researchers commonly "shrink" raw quality measures based on statistical criteria. This paper studies when and how this transformation's statistical properties would confer economic benefits to a utility‐maximizing decision‐maker across common asymmetric information environments. I develop the results for an application measuring teacher quality. The presence of a systematic relationship between teacher quality and class size could cause the data transformation to do either worse or better than the untransformed data. I use data from Los Angeles to confirm the presence of such a relationship and show that the simpler raw measure would outperform the one most commonly used in teacher incentive schemes. [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]

The purpose of this study was to examine the influence of six psychographic variables (materialism, novelty seeking, personal gratification, status consumption, value consciousness, and integrity) and three demographic variables (age, gender, and income) on attitude and purchase intention toward counterfeit apparel within the ports of Los Angeles and Long Beach. A paper‐based survey method was used with a convenience sample of college students at a large university in Los Angeles County. A total of 118 usable responses were obtained. Results of two separate sets of multiple regression analyses showed a significant and positive influence of attitude on purchase intention of counterfeit apparel. Value consciousness and integrity were negatively related to the purchase intention. Results also showed that men and people in the lower income range had more positive purchase intention toward counterfeit apparel. Implications for future research were also discussed. [ABSTRACT FROM AUTHOR]

Coronavirus 2019 (COVID‐19) captured worldwide attention as the virus spread from initial detection as a pneumonia of unknown cause in Wuhan, China in December 2019 to the declaration of a pandemic by the WHO only 3 months later. This paper describes the impact of COVID‐19 on cardiac surgery services in the greater Los Angeles area. Discussion includes public health response to the pandemic, how local hospitals reacted to the expected surge in patients with COVID, the establishment of telemedicine services, and the projected future impact on California healthcare as a result of the COVID‐19 pandemic. [ABSTRACT FROM AUTHOR]

The article discusses a study which examines the presence of metals and polycyclic aromatic hydrocarbons (PAH) at highway stormwater runoff in Los Angeles, California. Researchers stated that the degradation of pavement is one of the main sources of heavy metals in highway runoff. They found dissolved fractions of nickel, copper and zinc at three sites in the city.

SUMMARY Non-ductile reinforced concrete buildings represent a prevalent construction type found in many parts of the world. Due to the seismic vulnerability of such buildings, in areas of high seismic activity non-ductile reinforced concrete buildings pose a significant threat to the safety of the occupants and damage to such structures can result in large financial losses. This paper introduces advanced analytical models that can be used to simulate the nonlinear dynamic response of these structural systems, including collapse. The state-of-the-art loss simulation procedure developed for new buildings is extended to estimate the expected losses of existing non-ductile concrete buildings considering their vulnerability to collapse. Three criteria for collapse, namely first component failure, side-sway collapse, and gravity-load collapse, are considered in determining the probability of collapse and the assessment of financial losses. A detailed example is presented using a seven-story non-ductile reinforced concrete frame building located in the Los Angeles, California. Copyright © 2012 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

SUMMARY This paper addresses the topic of evaluating and strengthening a tall building in the Los Angeles region. Failure is characterized by the reliability index in terms that can be readily understood by structural engineers with only a basic knowledge of probability theory. The presented formulation requires the structural engineer to believe that the assumption of a normal or log-normal probability density function for capacity and demand is acceptable for the evaluation and strengthening of a tall building in the Los Angeles region. Copyright © 2012 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

SUMMARY A series of hybrid and cyclic loading tests were conducted on a three-story single-bay full-scale buckling-restrained braced frame (BRBF) at the Taiwan National Center for Research on Earthquake Engineering in 2010. Six buckling-restrained braces (BRBs) including two thin BRBs and four end-slotted BRBs, all using welded end connection details, were installed in the frame specimen. The BRBF was designed to sustain a design basis earthquake in Los Angeles. In the first hybrid test, the maximum inter-story drift reached nearly 0.030 rad in the second story and one of the thin BRBs in the first story locally bulged and fractured subsequently before the test ended. After replacing the BRBs in the first story with a new pair, a second hybrid test with the same but reversed direction ground motion was applied. The maximum inter-story drifts reached more than 0.030 rad and some cracks were found on the gusset welds in the second story. The frame responses were satisfactorily predicted by both OpenSees and PISA3D analytical models. The cyclic loading test with triangular lateral force distribution was conducted right after the second hybrid test. The maximum inter-story drift reached 0.032, 0.031, and 0.008 rad for the first to the third story, respectively. This paper then presents the findings on the local bulging failure of the steel casing by using cyclic test results of two thin BRB specimens. It is found that the steel casing bulging resistance can be computed from an equivalent beam model constructed from the steel core plate width and restraining concrete thickness. This paper concludes with the recommendations on the seismic design of thin BRB steel casings against local bulging failure. Copyright © 2011 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

The concept of unions as political mobilization groups is not well documented relative to the general determinants of voting behavior and labor’s traditional political roles. Specifically, scholars have yet to study the interaction between individuals’ propensities to vote and labor-led mobilization. Does labor have a stronger influence on frequent, occasional, or non-voters? Using data totaling 188,551 individuals in Los Angeles over five elections, this paper empirically studies the interaction between vote propensity and mobilization, finding that occasional voters are generally most receptive to labor’s efforts, particularly amongst Latinos, and that personal visits and phone calls are successful for occasional voters. [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 first introduces the key players involved in the deployment of Intelligent Transportation Systems (ITS) technologies in the Los Angeles metropolitan area. The paper then reports the local deployment status of major Advanced Public Transportation Systems (APTS) projects, with a particular emphasis placed on the burgeoning Los Angeles Smart Shuttle Demonstration Project. In addition, the paper analyzes some technical, political, financial and other issues centering around the deployment of APTS technologies in the Los Angeles metropolitan area. [ABSTRACT FROM AUTHOR]

In the midst of dramatic changes to American health care law there is need to understand the challenges that vulnerable populations encounter in obtaining and managing health insurance. Research has found that child language brokers, children who mediate language and culture for their immigrant families, assist with health-related matters. We report on focus groups with 17 language brokers living in Central Los Angeles. In this article we detail their experiences language brokering for health insurance and their knowledge of health insurance and policies that apply to their immigrant families. We illuminate some barriers immigrant families face as well as how they navigate them. We conclude with policy implications, particularly in relation to making health insurance more accessible to non-English speaking and immigrant populations. [ABSTRACT FROM AUTHOR]

This paper studies unobserved heterogeneity in hedonic price models, arising from missing property and locational characteristics. Specifically, commercial real estate is very heterogeneous, and data on detailed property characteristics are often lacking. We show that adding mutually independent property random effects to a hedonic price model results in more precise out‐of‐sample price predictions, both for commercial multifamily housing in Los Angeles and owner‐occupied single‐family housing in Heemstede, the Netherlands. The standard hedonic price model does not take advantage of the fact that some properties sell more than once. We subsequently show that adding spatial random effects leads to an additional increase in prediction accuracy. The increase is highest for properties without prior sales. [ABSTRACT FROM AUTHOR]

Catastrophic landslides are often preceded by slow, progressive, accelerating deformation that differs from the persistent motion of slow‐moving landslides. Here, we investigate the motion of a landslide that damaged 12 homes in Rolling Hills Estates (RHE), Los Angeles, California on 8 July 2023, using satellite‐based synthetic aperture radar interferometry (InSAR) and pixel tracking of satellite‐based optical images. To better understand the precursory motion of the RHE landslide, we compared its behavior with local precipitation and with several slow‐moving landslides nearby. Unlike the slow‐moving landslides, we found that RHE was a first‐time progressive failure that failed after one of the wettest years on record. We then applied a progressive failure model to interpret the failure mechanisms and further predict the failure time from the pre‐failure movement of RHE. Our work highlights the importance of monitoring incipient slow motion of landslides, particularly where no discernible historical displacement has been observed. Plain Language Summary: Landslides exhibit a wide range of behaviors around the world. Some landslides travel slowly downslope (velocities <1 m/yr) over a period of years or even decades. In contrast, other landslides fail catastrophically and travel downslope at high rates (>1 m/s), claiming lives and causing major damages. In some cases, these catastrophic landslides also display a precursory period of slow movement which presents an opportunity to detect them before they rapidly collapse. Here we investigated the movement of the Rolling Hills Estates (RHE) landslide, Los Angeles, California, before it moved many meters and damaged more than 12 houses on 8 July 2023. This landslide occurred after one of the wettest years on record in California. We found that the RHE landslide started sliding in 2023 in response to relatively high precipitation without obvious signs of movement in the three years preceding this event. This behavior differed starkly from the persistent motion of nearby slow‐moving landslides that experienced nearly identical rainfall conditions. Our findings show that the RHE can be defined as a progressive failure and its failure time can be estimated approximately through analyzing its movement before the occurrence of the failure. Key Points: We used satellite remote sensing to characterize the precursory motion of a catastrophic landslideProgressive failures and slow‐moving landslides can be distinguished by analyzing their time‐dependent motionSpecial attention should be given to landslides where no apparent historical movement has occurred [ABSTRACT FROM AUTHOR]

To address the shortage of the aggregate used in a hot mix asphalt (HMA) pavement in Guangxi, properties such as the aggregate crushing, polished stone, and Los Angeles abrasion values of a type of hard sandstone aggregate used in HMA were tested after various conditioning treatments. The hard sandstone aggregate met the technical requirements for aggregate in HMA. In addition, the influence of the Marshall compaction on the hard sandstone aggregate-combined grading was tested. The combined grading curve changed a little, and the aggregate satisfied the corresponding technical requirements. Therefore, according to the abovementioned results, the hard sandstone aggregate can be used as a coarse aggregate in HMA. [ABSTRACT FROM AUTHOR]

Solar photovoltaics (PV) are a renewable electricity technology with lower carbon dioxide equivalent (CO2e) impacts compared to fossil electricity, making it a technology of interest with respect to combatting global climate change. This paper combines agent‐based modeling (ABM) with life cycle assessment (LCA) to simulate rooftop solar PV adoption in Los Angeles (LA) County from 2018–2050 and generate CO2e impact data at the societal level to compare PV and grid electricity. With respect to solar PV panels, consumer adoption is the "pull" that moves the system and corresponding life cycle CO2e impacts forward. ABM is used to evaluate the impact of policies and evolutions in technology regarding the adoption of solar PV. Life cycle assessment is used to quantify the life cycle CO2e impacts of solar PV (including raw materials, manufacturing, and use). The results show that scenarios that increase PV adoption also increase the CO2e impacts from solar PV use in the short term, due to the raw materials and manufacturing portions of the life cycle. Yet, in the long term, adoption of solar PV may provide CO2e impact savings from offsetting grid electricity (although this is dependent on the carbon intensity of the electricity sources). The CO2e impacts of solar panels are dominated by the raw materials and manufacturing phases on a product level basis, but the use phase contributes to the majority of environmental impact savings from an adoption and societal‐level perspective. Future work may apply the methodology to other locations in the United States to evaluate if solar panels are an advantageous electricity source compared to the environmental impacts of the electricity grid. Integr Environ Assess Manag 2020;16:1008–1018. © 2020 SETAC KEY POINTS: Residential solar PV has the potential to be adopted at an increasing rate due to a variety of policy and market incentives.The environmental impact of manufacturing solar PV is relatively low compared to its potential to save GHG emissions during the use phase.Coupling agent based modeling and life cycle assessment results have the potential to yield new insights. [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]

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]

SUMMARY Two key issues distinguish probabilistic seismic risk analysis of a lifeline or portfolio of structures from that of a single structure. Regional analysis must consider the correlation among lifeline components or structures in the portfolio, and the larger scope makes it much more computationally demanding. In this paper, we systematically identify and compare alternative methods for regional hazard analysis that can be used as the first part of a computationally efficient regional probabilistic seismic risk analysis that properly considers spatial correlation. Specifically, each method results in a set of probabilistic ground motion maps with associated hazard-consistent annual occurrence probabilities that together represent the regional hazard. The methods are compared according to how replicable and computationally tractable they are and the extent to which the resulting maps are physically realistic, consistent with the regional hazard and regional spatial correlation, and few in number. On the basis of a conceptual comparison and an empirical comparison for Los Angeles, we recommend a combination of simulation and optimization approaches: (i) Monte Carlo simulation with importance sampling of the earthquake magnitudes to generate a set of probabilistic earthquake scenarios (defined by source and magnitude); (ii) the optimization-based probabilistic scenario method, a mixed-integer linear program, to reduce the size of that set; (iii) Monte Carlo simulation to generate a set of probabilistic ground motion maps, varying the number of maps sampled from each earthquake scenario so as to minimize the sampling variance; and (iv) the optimization-based probabilistic scenario again to reduce the set of probabilistic ground motion maps. Copyright © 2012 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

This paper concentrates on investigating the seismic behaviours of vertically irregular steel special moment frame (SMF) buildings by comparison with the regular counterpart. All buildings in this study were assumed to be located in Los Angeles, and subjected to 20 earthquake ground motions with a seismic hazard level of 2% probability of exceedance in 50 years. The beam-column connections of the buildings were modelled to consider the panel zone deformation. In addition, a ductile connection model accompanied by strength degradation was incorporated to the analysis programme in an effort to obtain more accurate response results. Three types of irregularities (mass, stiffness and strength irregularity) specified as vertical irregularities in the IBC 2000 provisions were imposed to the original building. Nonlinear static and dynamic analyses were performed, and the confidence levels of which the performance objective will be satisfied were calculated as well. The effects of different irregularity types and levels on the seismic behaviours of the buildings were investigated and discussed in terms of the height-wise distribution of storey drifts, maximum storey drift demands, global collapse storey drift capacities and confidence levels. Copyright © 2010 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

SUMMARY The architectural expressions for many modern buildings require creative and unconventional structural solutions. Columns must be taller, beams must span further, the structure must be more slender, elements must be curved, structural framing must be sloped and connections must deviate from conventional orthogonal fit-up. Although the technology exists to analyze and design responsive structural systems, prescriptive code requirements oftentimes hinder the implementation of those technologies. Although not a 'tall building' by traditional definition, the Tom Bradley International Terminal (TBIT) Modernization Program at Los Angeles International Airport (LAX) provides an appropriate case study in the implementation of unconventional structural geometry subject to code requirements that prescribe contrasting conventional geometry, which is a familiar challenge for many tall buildings. The architectural expression for the LAX TBIT Modernization Program required the use of long-span steel Special Moment Frames with non-orthogonal moment connections between the beams and columns. The beams were sloped, some were sloped and curved and some of the columns were sloped. The reduced beam section (RBS) moment connection was selected for the project. ANSI/AISC 358, Prequalified Connections for Special and Intermediate Steel Moment Frames for Seismic Applications, provides prequalification limits for using an RBS connection. Those limits do not address non-orthogonal moment connections. ANSI/AISC 358 implicitly limits connections to orthogonal geometry; hence, non-orthogonal moment connections are not prequalified for use in seismic applications. This paper describes the structure and the cyclic testing program that was implemented to qualify the proposed non-orthogonal RBS connections in accordance with ANSI/AISC 341, Seismic Provisions for Structural Steel Buildings, Appendix S for use on the LAX TBIT Modernization Project. Copyright © 2011 John Wiley & Sons, Ltd. [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]

Three of the tall buildings that members of the Los Angeles Tall Buildings Structural Design Council visited after the 27 February 2010 Chilean moment magnitude 8.8 earthquake were reviewed. The three buildings discussed in this paper are located in the Greater Concepción area in the Biobió Region (Region VIII) of Chile. Two of the buildings (Bosquemar and Olas) are located on the west side of the Bio-Bio River in San Pedro de La Paz, while the third building (Pedro de Valdivia) is located on the east side of the river south of the downtown area of the city of Concepción. The tower at Bosquemar was the most thoroughly investigated, although the observations from the damage at all three structures offer important insight that can be applied to current and future earthquake engineering practice. Copyright © 2010 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]