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To identify subgroups of parents' food choice value systems and evaluate associations with restaurant eating behaviors of children. Cross-sectional survey. Parents with low income and children aged 2–11 years who were frequent restaurant visitors before the coronavirus disease 2019 pandemic (n = 1,146). Past week restaurant meals and the healthfulness of child meal orders. We used latent class analysis to identify patterns of stated food choice values (convenience, taste, cost, cooking, nutrition, locality, socialization, and food safety reputation) among parents. Logistic and linear regression models evaluated differences in child restaurant eating behaviors across classes. Three classes of parents' stated food choice values were identified: hassle-free, indulgent, and multifaceted consumers (7.94%, 54.97%, and 37.09% of parents, respectively). The children of the hassle-free consumers class were 91% less likely to select a healthy entree than an unhealthy entree and were even less likely to select a healthy entree than those of the indulgent and multifaceted consumer classes (P < 0.02). The multifaceted consumers class ate from restaurants the most in the last week (2.4 vs 2.1 and 1.9 times; P < 0.02). This subgroup approach could inform future restaurant interventions by tailoring to differences in parents' food choice values. [ABSTRACT FROM AUTHOR]

In terms of pedagogy, there is a need in introductory sensation and perception courses for practice problems that promote critical thinking and elaborate on course material, like those given in the physical sciences. However, perceptual psychology mostly lacks the mathematical foundations that provide ready material for such elaborative assignments. Here I introduce a series of short assignments dubbed Purple Perils, which are inspired by the perception-related missives made famous by J. J. Gibson. These assignments provide students with open-ended opportunities to think through compelling and relatable problems in perception, often with an applied component. By their nature, such assignments are at present somewhat resistant to large language model AI assistance: probes of ChatGPT suggest that students who illicitly use such systems may not gain the synthesis of ideas that Purple Perils demand, and will therefore be disincentivized to use such illicit aid. This kind of assignment can reinforce learning in topics across sensory modalities, and can be used for exam questions. Purple Perils promote critical thinking and quantitative reasoning, e.g., through graphical literacy; reinforce biological knowledge; encourage classroom debate and discussion; and connect to historical and contemporary debates and findings. Gibson’s own Purple Peril about the El Greco fallacy leads the series of assignments. A protected, crowd-sourced, repository of Purple Perils is also deployed to allow sharing of questions among instructors. [ABSTRACT FROM AUTHOR]

Frequentist semiparametric theory has been used extensively to develop doubly robust (DR) causal estimation. DR estimation combines outcome regression (OR) and propensity score (PS) models in such a way that correct specification of just one of two models is enough to obtain consistent parameter estimation. An equivalent Bayesian solution, however, is not straightforward as there is no obvious distributional framework to the joint OR and PS model, and the DR approach involves a semiparametric estimating equation framework without a fully specified likelihood. In this paper, we develop a fully semiparametric Bayesian framework for DR causal inference by bridging a nonparametric Bayesian procedure with empirical likelihood via semiparametric linear regression. Instead of specifying a fully probabilistic model, this procedure is only realized through relevant moment conditions. Crucially, this allows the posterior distribution of the causal parameter to be simulated via Markov chain Monte Carlo methods. We show that the posterior distribution of the causal estimator satisfies consistency and the Bernstein–von Mises theorem, when either the OR or PS is correctly specified. Simulation studies suggest that our proposed method is doubly robust and can achieve the desired coverage rate. We also apply this novel Bayesian method to a real data example to assess the impact of speed cameras on car collisions in England. [ABSTRACT FROM AUTHOR]

Recent years saw immense growth in performance measurement literature related to public transit systems, with a clear segmentation between financial and quality-of-service performance frameworks. Recently, there has been a shift away from considering cost efficiency alone as a performance measure, and quality-of-service – which influences ridership attraction and retention – has been receiving more interest. The segmentation of these two performance aspects poses a gap in the literature, as there are interdependencies between them. This study provides a systematic review of the methodologies and empirical findings of studies on both performance measurement aspects of urban rail transit systems; specifically, we demonstrate the importance of linking cost efficiency analyses to the level of service quality. To our knowledge, this is the first review of urban rail transit research that links the two performance aspects. We begin by reviewing the methodological limitations of cost performance measures and summarising the drivers of cost performance in the existing literature. We then review studies on the definitions and measurements of quality-of-service in urban rail performance. Lastly, we summarise the scant literature linking the two performance aspects and highlight future study directions, mainly, the importance of a structural framework to provide a holistic view of transit operators' performance. [ABSTRACT FROM AUTHOR]

Secondary ion mass spectrometry using the argon cluster primary ion beam enables molecular compositional depth profiling of organic thin films with minimal loss of chemical information or changes in sputter rate. However, for depth profiles of thicker organic films (>10 μm of sputtered depth), we have observed the rapid formation of micron‐scale topography in the shape of pillars that significantly affect both the linearity of the sputter yield and depth resolution. To minimize distortions in the 3D reconstruction of the sample due to this topography, a stepwise, staggered sample rotation was employed. By using polymer spheres embedded in an organic film, it was possible to measure the depth resolution at the film‐sphere interface as a function of sputtered depth and observe when possible distortions in the 3D image occurred. In this way, it was possible to quantitatively measure the effect of micron‐scale topography and sample rotation on the quality of the depth profile. [ABSTRACT FROM AUTHOR]

This study assesses whether the negative exogenous informational shock of the MeToo scandal has affected women's perception of security. The MeToo movement was first reported in the media worldwide in October 2017, and has received enormous press coverage since then. The exogenous and unanticipated nature of the scandal provides a natural experiment that we can use to quantify how wider external information affects 'ordinary' women's perceptions of security and their willingness to report feelings of dissatisfaction with security levels. To do so, we use a case study of women's' perception of security in 12 metro systems in Europe, for which we have large-scale unique customer satisfaction data over the years 2014 to 2018. We use interview dates to determine perceptions pre and post scandal, and we take the MeToo scandal as a 'treatment' affecting women in the sense that they were the primary target of the informational shock. Using pre and post treatment data, for our defined treated (women) and control (men) units, we apply a difference-in-differences estimator to identify the impact of the scandal on perceptions of security. Our results show a 2.5% increase in the probability of women being dissatisfied with security in stations and in metro carriages post-scandal. These results support the conclusion that revealed preferences are only revealed up to a certain extent. A change in the context (e.g. , an informational shock), can alter perceptions and in turn, can encourage individuals to disclose lower (or higher) satisfaction levels as perceptions of the norm change. [ABSTRACT FROM AUTHOR]

In this paper we use large-scale mass transit data to improve the journey time performance measurement of urban bus systems. For low frequency bus services, the application of on-time performance (OTP) metrics, particularly the location and number of stops to sample, varies greatly across operators, which can lead to biased estimates. In this paper, we aim to address sampling disparity, and propose a new statistically robust sampling scheme to ensure representative, non-biased, and comparable measurement of route level on time performance (OTP) which enables the inclusion of operators with sparse data in benchmarking activities. We use automated vehicle location data and analyse 59 unique low frequency route-direction data sets from 9 international bus operators. Across all route-direction data sets, an average of 28% of stops are required to be sampled under the defined sampling scheme to achieve a 95% confidence level of sampling the route-level mean within a ± 5% range of accuracy. By including data on additional routes, the analysis can be further refined and generalised to enable progressive improvement of inter-operator comparability and benchmarking. [ABSTRACT FROM AUTHOR]

• Estimated the causal economic impact of an off-peak fare discount in Hong Kong. • Applied the difference-in-difference method to control for confounding bias. • Found the aggregate effect to be small but statistically significant and heterogeneous. • Responsiveness was governed by travel costs and crowding. • Produced novel causal estimates of trip rescheduling elasticities. This paper quantifies the causal impact of differential pricing on the trip-scheduling of regular commuters using the Mass Transit Railway (MTR) in Hong Kong. It does so by applying a difference-in-difference (DID) method to large scale smart card data before and after the introduction of the Early Bird Discount (EBD) pricing intervention. We find statistically significant but small effects of the EBD in the form of earlier departure times. Leveraging the granularity of the data, we also allow for the treatment effect to vary over observed travel characteristics. Our empirical results suggest that fares and crowding are the key determinants of commuter responsiveness to the EBD policy. [ABSTRACT FROM AUTHOR]

• Estimated a short-run cost function for urban rail transport (i.e. metro) operations • Used a unique panel dataset of 24 metro operations from across the globe. • Addressed various endogeneity challenges in such empirical analysis. • Found metro systems with high density of usage to be the most cost-efficient. • Provided new insights into existence of economies of scale in metro operations. There is considerable variation in the average cost of operations across urban rail transport (or metro) systems. Since metros are typically owned and operated by public authorities, there is a public interest case in understanding the key drivers of their operational costs. This paper estimates short-run cost functions for metro operations using a unique panel dataset from twenty-four metro systems around the world. We use a flexible translog specification and apply dynamic panel generalised method of moments (DPGMM) estimation to control for confounding from observed and unobserved characteristics of metro operations. Our empirical results show that metro systems with a high density of usage are the most cost-efficient. We also find that operational costs fall as metro size increases. These results have important implications for the economic appraisal of metro systems. [ABSTRACT FROM AUTHOR]

The impacts of air transport on the economy arise both directly, via activity in the aviation sector; and indirectly, via increased spending and wider economic benefits associated with improved access to resources, markets, technology and economic mass. Economic activity, in turn, supports and generates demand for air transport. Despite its potential importance, the reciprocal nature of the causal relationship between air transport and economic performance has remained somewhat understudied. This paper provides a synthesis review of the channels the aviation sector interacts with regional economy. The review focuses on quantitative studies that contribute to the state-of-the-art understandings of the causality. We find that the reciprocal causal relationship is more likely to prevail in less developed economies. For more developed economies, only one direction of the causality is recognised, which runs from air transport to economic growth. Especially substantial is the effect of airline enplanement on service-related employment. The reverse direction of the relationship is, however, not as significant as believed in a causal sense within the developed world. Therefore, cautions need to be taken when applying income elasticities (such as the elasticity of air passenger demand with respect to GDP) in air travel demand forecasting, which implicitly assumes that economic growth causally leads to air traffic increment. Based on the fundamental links between air transport and economic growth, some typical imperfections and inefficiencies in aviation markets are discussed and promising avenues for future research are proposed. [ABSTRACT FROM AUTHOR]

Surfaces represent a unique state of matter that typically have significantly different compositions and structures from the bulk of a material. Since surfaces are the interface between a material and its environment, they play an important role in how a material interacts with its environment. Thus, it is essential to characterize, in as much detail as possible, the surface structure and composition of a material. However, this can be challenging since the surface region typically is only minute portion of the entire material, requiring specialized techniques to selectively probe the surface region. This tutorial will provide a brief review of several techniques used to characterize the surface and interface regions of biological materials. For each technique we provide a description of the key underlying physics and chemistry principles, the information provided, strengths and weaknesses, the types of samples that can be analyzed, and an example application. Given the surface analysis challenges for biological materials, typically there is never just one technique that can provide a complete surface characterization. Thus, a multi-technique approach to biological surface analysis is always required. [ABSTRACT FROM AUTHOR]

• This study presents the first macro-level cross-country analysis of urban rail transit safety. • The study utilizes an international dataset from 31 systems to analyze the operational safety of urban rail. • This study applies supervised machine learning models which consider the socio-technical nature and non-linear interactions. • This study provides a benchmarking model for urban rail transit safety outputs which accommodates heterogeneity. This paper studies the operational safety of urban rail transit (URT) systems through Artificial Neural Networks. While recent safety literature adopting systematic models of analysis consider the complexity of URT operations, they focus on single systems or single components of the operational process. Our study contributes to the URT safety literature by having a macro perspective, while considering that such complex socio-technical systems involve multiple non-linear interactions among their components. To our knowledge, we present the first cross-country analysis of URT safety through machine learning models in the literature, using a unique international dataset from 31 URT systems which comprises annual system-level data. Two models are estimated to predict the annual URT injuries. The first model includes safety-related incidents as inputs, while the second includes operational characteristics of the system. Additionally, a closed-form formula is presented to predict the annual number of injuries based on operational features of the URT system along with an illustrative example to demonstrate benchmarking applications. The results are promising and indicate good generalizability. The models proposed in this study could be useful for operators and policy makers as they aid in prioritizing improvements, predicting future safety performance based on changes in operational features, and as a benchmarking tool. [ABSTRACT FROM AUTHOR]

This paper quantifies the effect of speed cameras on road traffic collisions using an approximate Bayesian doubly-robust (DR) causal inference estimation method. Previous empirical work on this topic, which shows a diverse range of estimated effects, is based largely on outcome regression (OR) models using the Empirical Bayes approach or on simple before and after comparisons. Issues of causality and confounding have received little formal attention. A causal DR approach combines propensity score (PS) and OR models to give an average treatment effect (ATE) estimator that is consistent and asymptotically normal under correct specification of either of the two component models. We develop this approach within a novel approximate Bayesian framework to derive posterior predictive distributions for the ATE of speed cameras on road traffic collisions. Our results for England indicate significant reductions in the number of collisions at speed cameras sites (mean ATE = -15%). Our proposed method offers a promising approach for evaluation of transport safety interventions. [ABSTRACT FROM AUTHOR]

• We compare the performance of EB and PS methods via simulation studies. • PS models perform well with large samples and sufficient balance in covariates. • The EB estimators can be biased when units follow different SPFs. • DR models allow for violation of assumptions and provide additional robustness. Statistical evaluation of road safety interventions can be undertaken using a variety of different approaches, typically requiring different assumptions to obtain causal identification. In this paper, we conduct a simulation study to compare the performance of empirical Bayes (EB) and propensity score (PS) based methods, which have featured prominently in the recent literature, in settings with and without violation of key assumptions. The estimators considered include EB, inverse probability weighting (IPW), and Doubly Robust (DR) estimation. We find that while the EB approach has good finite sample properties when model assumptions are met, the consistency of this estimator is substantially diminished when the reference and treated sites follow different functions. The IPW estimator performs well in large samples, but requires a correctly specified PS model with sufficient overlap in covariate distributions between treated and control units. The DR estimator allows for violation of assumptions in either the regression or PS model, but not both. We find that this added level of robustness affords overall better performance than attained via EB or IPW estimation. [ABSTRACT FROM AUTHOR]

This paper evaluates economic impacts arising from the introduction of high-speed rail (HSR) between Madrid and Barcelona. Using difference-in-differences estimation we estimate an average treatment effect for provinces with stops on the HSR line of 2.4% for economic output, 3.3% for numbers of firms, and 1.1% for labour productivity. We complement our DID results with a synthetic control analysis for Lleida and Tarragona, two provinces that we argue were assigned HSR stations largely due to their incidental location. We find that both the number of firms and labour productivity are substantially higher in these provinces than in their synthetic counterparts. [ABSTRACT FROM AUTHOR]

Abstract This paper quantifies the substitution and complementary effects of high-speed rail (HSR) on air travel demand in terms of both route traffic and airport enplanement. Employing the difference-in-differences (DID) method, the first part of the analysis measures the effect of new HSR routes on parallel air route traffic with a focus on East Asian regions (Mainland China, Japan, South Korea, and Taiwan). The second part examines the effect of air-HSR integration on passenger enplanement at East Asian airports and compares with that in the Central European market. We find that in general the airport's access cost (reflected by the distance from central city) has a negative impact on the air traffic. The substitution effects of HSR are the most significant on short- and medium-haul (below 1000 km) air routes while introducing HSR services has encouraged long distance (over 1000 km) air travels in Mainland China. The complementary effect is investigated in the context of air-HSR integration, which has significantly positive impacts on airport enplanement at primary hub airports when fitted with on-site HSR links. The benefit is limited at secondary hubs and regional airports possibly by locations and HSR service frequencies. [ABSTRACT FROM AUTHOR]

Emission spectra indicating transient clusters in a supersonic nitrogen discharge are presented. Select spectral bands are attributed to emission from N2(C 3Πu,v’=0,1)–N2(X 1Σg+). The cluster transitions manifest as blue-degraded, blue-shifted sidebands of the second positive group due to emission from N2(C 3Πu). Results and significance concerning these previously undiscovered nitrogen clusters are discussed. [ABSTRACT FROM AUTHOR]

We present a method whereby the excited triplet state of diphenylmethylene can be populated in a spin-polarized manner. The method features sensitization by benzophenone triplet excitons. We ascertain the spin-polarized nature of the excited triplet by observing magnetic field effects on the fluorescence. The observed effects provide information concerning the spin dipolar and intersystem crossing nature of excited diphenylmethylene. [ABSTRACT FROM AUTHOR]

This paper investigates multi-period public transport supply, i.e. networks in which capacity cannot be differentiated between links and time periods facing independent but nonidentical demand conditions. This setting is particularly relevant in public transport, as earlier findings on multi-period road supply cannot be applied when the user cost function, defined as the sum of waiting time and crowding costs, is nonhomogeneous. The presence of temporal, spatial and directional demand imbalances is unavoidable in a public transport network. It is not obvious, however, how the magnitude of demand imbalances may affect its economic and financial performance. We show in a simple back-haul setting with elastic demand, controlling for total willingness to pay in the network, that asymmetries in market size reduce the attainable social surplus of a service, while variety in maximum willingness to pay leads to higher aggregate social surplus and lower subsidy under efficient pricing. The analysis of multi-period supply sheds light on the relationship between urban structure, daily activity patterns, and public transport performance. [ABSTRACT FROM AUTHOR]

Seated and standing travelling imply significantly different experience for public transport users. This paper investigates with analytical modelling and numerical simulations how the optimal seat supply depends on demand and supply characteristics. The paper explores the implications of seat provision on the marginal cost of travelling as well. In crowded conditions, we distinguish two types of external costs: crowding density and seat occupancy externalities. We derive, using a realistic smart card dataset, the externality pattern of a metro line, and identify the distorting role of the occupancy externality that makes the welfare maximising fare disproportionate to the density of crowding. [ABSTRACT FROM AUTHOR]

This paper evaluates the effects of the London Cycle Superhighways (CS) on cycle collisions. A total of 45 CS segments and 375 control segments are observed for a period of 8 years in London. Variables such as road characteristics, crash history and socio-economic information are included in the data set. Traffic characteristics including traffic volume, cycle volume and traffic speed are obtained from Department for Transport. We first estimate the safety effects on the CS routes using Empirical Bayes methods. Then propensity score matching methods are also applied for comparison. The introduction of cycle superhighways caused cycling traffic volumes to increase dramatically along CS routes with no significant impacts on collision rates. Our models find that the increase in traffic was associated with a rise in annual total cycle collisions of around 2.6 per km (38% in percentage). However, when we re-estimate the effects based on cycle collision rates rather than levels, our results also show that the CS routes are not more dangerous or safer than the control roads. Among the four CS routes, CS3 performs the best in protecting cyclists with a large proportion of segregated lanes whilst the cyclists have to share the lanes with motorists on other routes. It is recommended that consistent safety designs should be applied on all CS routes for a safer cycling environment. [ABSTRACT FROM AUTHOR]

This paper estimates the productivity gains from agglomeration economies for a sample of the largest metropolitan areas in the United States using measures of urban agglomeration based on employment density and employment accessibility. The latter is a more accurate measure of economic proximity and allows testing for the spatial decay of agglomeration effects with increasing travel time. We find that the productivity gains from urban agglomeration are consistent between measures, with elasticity values between 0.07 and 0.10. The large majority of the productivity gains occur within the first 20 minutes, and do not appear to exhibit significant nonlinearities. [ABSTRACT FROM AUTHOR]

Crowding discomfort is an external cost of public transport trips imposed on fellow passengers that has to be measured in order to derive optimal supply-side decisions. This paper presents a comprehensive method to estimate the user cost of crowding in terms of the equivalent travel time loss, in a revealed preference route choice framework. Using automated demand and train location data we control for fluctuations in crowding conditions on the entire length of a metro journey, including variations in the density of standing passengers and the probability of finding a seat. The estimated standing penalty is 26.5% of the uncrowded value of in-vehicle travel time. An additional passenger per square metre on average adds 11.9% to the travel time multiplier. These results are in line with earlier revealed preference values, and suggest that stated choice methods may overestimate the user cost of crowding. As a side-product, and an important input of the route choice analysis, we derive a novel passenger-to-train assignment method to recover the daily crowding and standing probability pattern in the metro network. [ABSTRACT FROM AUTHOR]

This paper analyses how the effects of fixed speed cameras on road casualties vary across sites with different characteristics and evaluates the criteria for selecting camera sites. A total of 771 camera sites and 4787 potential control sites are observed for a period of 9 years across England. Site characteristics such as road class, crash history and site length are combined into a single index, referred to as a propensity score. We first estimate the average effect at each camera site using propensity score matching. The effects are then estimated as a function of propensity scores using local polynomial regression. The results show that the reduction in personal injury collisions ranges from 10% to 40% whilst the average effect is 25.9%, indicating that the effects of speed cameras are not uniform across camera sites and are dependent on site characteristics, as measured by propensity scores. We further evaluate the criteria for selecting camera sites in the UK by comparing the effects at camera sites meeting and not meeting the criteria. The results show that camera sites which meet the criteria perform better in reducing casualties, implying the current site selection criteria are rational. [ABSTRACT FROM AUTHOR]

Congestion; operational delays due to a vicious circle of passenger congestion and train-queuing; is an escalating problem for metro systems because it has negative consequences from passenger discomfort to eventual mode shifts. Congestion arises due to large volumes of passenger boardings and alightings at bottleneck stations, which may lead to increased stopping times at stations and consequent queuing of trains upstream. Such queuing further reduces line throughput and implies an even greater accumulation of passengers at stations. Alleviating congestion requires control strategies such as regulating the inflow of passengers entering bottleneck stations. The availability of large-scale smartcard and train movement data from day-to-day operations facilitates the development of models that can inform such strategies in a data-driven way. In this paper, we propose to model station-level passenger congestion via empirical passenger boarding–alightings and train flow relationships, henceforth, fundamental diagrams (FDs). We emphasise that estimating FDs using station-level data is empirically challenging due to confounding biases arising from the interdependence of operations at different stations, which obscures the true sources of congestion in the network. We thus adopt a causal statistical modelling approach to produce FDs that are robust to confounding and as such suitable to inform control strategies. The closest antecedent to the proposed model is the FD for road sections, which informs traffic management strategies, for instance, via locating the optimum operation point. Our analysis of data from the Mass Transit Railway, Hong Kong indicates the existence of concave FDs at identified bottleneck stations, and an associated critical level of boarding–alightings above which congestion sets in unless there is an intervention. [ABSTRACT FROM AUTHOR]

• Using abnormal headway deviations as the indicator of metro disruptions. • A probabilistic, unsupervised and automatic detection method based on Gaussian mixture models and large-scale vehicle location data. • A novel algorithmic solution to empirically identify the propagation of disruption and the recovery intervention from operators. • The proposed framework is effective for any type of service interruption, including minor delays of just a few minutes. Urban metro systems are often affected by disruptions such as infrastructure malfunctions, rolling stock breakdowns and accidents. The crucial prerequisite of any disruption analytics is to have accurate information about the location, occurrence time, duration and propagation of disruptions. To pursue this goal, we detect the abnormal deviations in trains' headway relative to their regular services by using Gaussian mixture models. Our method is a unique contribution in the sense that it proposes a novel, probabilistic, unsupervised clustering framework and it can effectively detect any type of service interruptions, including minor delays of just a few minutes. In contrast to traditional manual inspections and other detection methods based on social media data or smart card data, which suffer from human errors, limited monitoring coverage, and potential bias, our approach uses information on train trajectories derived from automated vehicle location (train movement) data. As an important research output, this paper delivers innovative analyses of the propagation progress of disruptions along metro lines, which enables us to distinguish primary and secondary disruptions as well as effective recovery interventions performed by operators. [ABSTRACT FROM AUTHOR]

This paper estimates the causal effect of 20 mph zones on road casualties in London. Potential confounders in the key relationship of interest are included within outcome regression and propensity score models, and the models are then combined to form a doubly robust estimator. A total of 234 treated zones and 2844 potential control zones are included in the data sample. The propensity score model is used to select a viable control group which has common support in the covariate distributions. We compare the doubly robust estimates with those obtained using three other methods: inverse probability weighting, regression adjustment, and propensity score matching. The results indicate that 20 mph zones have had a significant causal impact on road casualty reduction in both absolute and proportional terms. [ABSTRACT FROM AUTHOR]

To properly process and reconstruct 3D ToF-SIMS data from systems such as multi-component polymers, drug delivery scaffolds, cells and tissues, it is important to understand the sputtering behavior of the sample. Modern cluster sources enable efficient and stable sputtering of many organics materials. However, not all materials sputter at the same rate and few studies have explored how different sputter rates may distort reconstructed depth profiles of multicomponent materials. In this study spun-cast bilayer polymer films of polystyrene and PMMA are used as model systems to optimize methods for the reconstruction of depth profiles in systems exhibiting different sputter rates between components. Transforming the bilayer depth profile from sputter time to depth using a single sputter rate fails to account for sputter rate variations during the profile. This leads to inaccurate apparent layer thicknesses and interfacial positions, as well as the appearance of continued sputtering into the substrate. Applying measured single component sputter rates to the bilayer films with a step change in sputter rate at the interfaces yields more accurate film thickness and interface positions. The transformation can be further improved by applying a linear sputter rate transition across the interface, thus modeling the sputter rate changes seen in polymer blends. This more closely reflects the expected sputtering behavior. This study highlights the need for both accurate evaluation of component sputter rates and the careful conversion of sputter time to depth, if accurate 3D reconstructions of complex multi-component organic and biological samples are to be achieved. The effects of errors in sputter rate determination are also explored. [ABSTRACT FROM AUTHOR]

In order to ensure a high level of road safety, road network planning needs to be based on the best knowledge available of the effects of road design on road safety. In this study, we look into how changes in road network characteristics affect road casualties. An approach based on traffic assignment is proposed in order to estimate the traffic exposure at ward level. We apply a widely used approach for before–after evaluation studies, the Bayesian method. We also use a panel semi-parametric model to estimate the dose–response function for continuous treatment variables. The result suggests that there are more casualties in areas with better connectivity and accessibility, where more attention should be paid to safety countermeasures. [ABSTRACT FROM AUTHOR]

Road network capacity expansions are frequently proposed as solutions to urban traffic congestion but are controversial because it is thought that they can directly “induce” growth in traffic volumes. This article quantifies causal effects of road network capacity expansions on aggregate urban traffic volume and density in U.S. cities using a mixed model propensity score (PS) estimator. The motivation for this approach is that we seek to estimate a dose-response relationship between capacity and volume but suspect confounding from both observed and unobserved characteristics. Analytical results and simulations show that a longitudinal mixed model PS approach can be used to adjust effectively for time-invariant unobserved confounding via random effects (RE). Our empirical results indicate that network capacity expansions can cause substantial increases in aggregate urban traffic volumes such that even major capacity increases can actually lead to little or no reduction in network traffic densities. This result has important implications for optimal urban transportation strategies. Supplementary materials for this article are available online. [ABSTRACT FROM AUTHOR]

Theability to control proton translocation is essential for optimizing electrocatalyticreductions in acidic solutions. We have synthesized a series of newhangman iron porphyrins with hanging groups of differing proton-donatingabilities and evaluated their electrocatalytic hydrogen-evolving abilityusing foot-of-the-wave analysis. In the presence of excess triphenylphosphine,iron porphyrins initiate proton reduction electrocatalysis upon reductionto FeI. By changing the proton-donating ability of thehanging group, we can affect the rate of catalysis by nearly 3 ordersof magnitude. The presence of an acid/base moiety in the second coordinationsphere results in a marked increase in turnover frequency when extrapolatedto zero overpotential. [ABSTRACT FROM AUTHOR]

This paper generates new evidence for England and Wales on the importance of labour pooling as a source of agglomeration economies. Estimates of worker and firm productivity are obtained from longitudinal worker and firm micro-data and used to test the hypothesis that denser labour markets increase the quality of the matching between employees and employers across labour markets. Our findings provide evidence supportive of a positive relationship between the quality of the employee-employer matching and the economic size of labour markets. [ABSTRACT FROM AUTHOR]

This paper estimates demand elasticities for diesel fuel in the UK using static error correction and dynamic ADL time series cointegration models. While there are studies focusing on elasticities in the road transport sector, most have either looked at petrol demand or have used road transport fuel demand. Our findings indicate that the income elasticities for diesel fuel, both in the short- and the long-run are significantly higher, and the long run price elasticity is relatively lower as compared to those reported in studies using fuel or petrol demand. [ABSTRACT FROM AUTHOR]

Highlights: [•] We use propensity score matching to evaluate the safety effect of speed cameras. [•] The propensity score can be used as the criteria for selecting the reference group. [•] Propensity score matching can improve the performance of the empirical Bayes. [•] Speed cameras are most effective up to 200m from camera sites. [ABSTRACT FROM AUTHOR]

Decision making in a rapidly changing context, such as the development and progression of a pandemic, requires a dynamic assessment of multiple variable and competing factors. Seemingly beneficial courses of action can rapidly fail to deliver a positive outcome as the context changes. In this paper, we present a flexible data-driven agent-based simulation framework that considers multiple outcome criteria to increase opportunities for safe mobility and economic interactions on urban transit networks while reducing the potential for Covid-19 contagion in a dynamic setting. Using a case study of the Victoria line on the London Underground, we model a number of operational interventions with varied demand levels and social distancing constraints including: alterations to train headways, dwell times, signalling schemes, and train paths. Our model demonstrates that substantial performance gains ranging from 12.3–195.7% can be achieved in metro service provision when comparing the best performing operational scheme and headway with those realised on the Victoria line during the pandemic. [ABSTRACT FROM AUTHOR]

Abstract: The literature on land and property values demonstrates a great deal of variability in the estimated change in values arising from rail investments. This paper conducts a meta-analysis on empirical estimates from 23 studies (102 observations) that analysed the impact of rail on land/property value changes. Variation in the estimated impacts is calculated and discussed in relation to key dimensions of study-design characteristics. The results show that a number of factors produce significant variations in the estimates. These include the type of land use, the type of rail service, the rail system life cycle maturity, the distance to stations, the geographical location, accessibility to roads, methodological characteristics, as well as whether the impacted area is land or property. On the other hand, we observe that changes in purchase price and rent values due to rail projects are statistically similar to each other, that there is no evidence of change in values over time nor due to the location of land/property within the city, and that including property characteristics and neighbourhood type in the estimation model do not change values significantly. Publication bias tests are also performed and show that although researchers tend to report both positive and negative results, they tend to be biased towards statistically significant estimates. [Copyright &y& Elsevier]

In this article, the authors offer to enhance knowledge and appreciation of the glass electrode's mechanistic uncertainty. The authors explain that the glass electrode, the most commonly used device to access the pH of an aqueous solution, attains highly accurate measurements through simple and well-established procedures. The article also references several studies regarding the glass electrode's response to pH such as the "Development of the Glass Electrode," by Moore and colleagues.

Abstract: This paper aims to identify the impacts of the London congestion charge on road casualties within the central London charging zone. It develops a full difference-in-difference (DID) model that is integrated with generalized linear models, such as Poisson and Negative Binomial regression models. Covariates are included in the model to adjust for factors that violate the parallel trend assumption, which is critical in the DID model. The lower Bayesian Information Criterion value suggests that the full difference-in-difference model performs well in evaluating the relationship between road accidents and the London congestion charge as well as other socio-economic factors. After adjusting for a time trend and regional effects, the results show that the introduction of the London congestion charge has a significant influence on the incidence of road casualties. The congestion charge reduces the total number of car accidents, but is associated with an increase in two wheeled vehicle accidents. [Copyright &y& Elsevier]

Proper display of three-dimensional time-of-flight secondary ion mass spectrometry (ToF-SIMS) imaging data of comples nonflat samples requires a correction of the data in the z-direction. Inaccuracies in displaying three-dimensional ToP-SIMS data arise from projecting data from a nonflat surface onto a 2D image plane, as well as possible variations in the sputter rate of the sample being probed. The current study builds on previous studies by creating software written in Matlab, the ZCorrectorGljl (available at http://mvsanb.uw.edu/), to apply the z-correction to entire 3D data sets. Three- dimensional image data sets were acquired from NIH/3T3 flbroblasts by collecting ToF-SIMS images, using a dual beam approach (25 keV Bi3+ for analysis cycles and 20 keV C602+ for sputter cycles). The entire data cube was then corrected by using the new ZCorrectorGUl software, producing accurate chemical information from single cells in 3D. For the first time, a three-dimensional corrected view of a lipid-rich subcellular region, possibly the nuclear membrane, is presented. Additionally, the key assumption of a constant sputter rate throughout the data acquisition was tested by using ToF-SIMS and atomic force microscopy (AFM) analysis of the same cells. For the dried NIH/3T3 fibroblasts examined in this study, the sputter rate was found to not change appreciably in x, y, or z, and the cellular material was sputtered at a rate of approximately 10 nm per 1.25 x 1013 ions C602+/cm2. [ABSTRACT FROM AUTHOR]

Generation of soluble sources of peroxide dianion (O22-) is a challenge in dioxygen chemistry. The oxidizing nature of this anion renders its stabilization in organic media difficult. This Report describes the chemically reversible reduction of oxygen (O2) to cryptand-encapsulated O22- The dianion is stabilized by strong hydrogen bonds to N-H groups from the hexacarboxamide cryptand. Analogous stabilization of peroxide by hydrogen bonding has been invoked recently in crystalline 5accharide and protein systems. The present peroxide adducts are stable at room temperature in dimethyl su[foxide (DMSO) and N,N′-dimethylformamide (DMF). These adducts can be obtained in gram quantities from the cryptand-driven disproportionation reaction of potassium superoxide (KO2) at room temperature. [ABSTRACT FROM AUTHOR]

The Pd(I)-Pd(I) dimer [(FPNP)Pd-]2 reacts with O2 upon exposure to light to produce either the superoxide (FPNP)PdO2 or the peroxide [(FPNP)PdO-]2, which exist in equilibrium with free O2. Both complexes contain square-planar Pd(II) centers. The unpaired electron density in (FPNP)PdO2 is localized on the superoxide ligand. [ABSTRACT FROM AUTHOR]

The productivity effects of agglomeration economies are often treated as endogenous in empirical work due to the potential for reverse causality. The extent to which these relationships are actually simultaneously determined, however, remains largely unobserved. This paper estimates panel data vector autoregressions for different sectors of the economy to test for bidirectional causality between productivity and both localization and urbanization economies. The aim is to address some key questions that will help to identify the extent of the endogeneity problem. Can we actually observe bidirectionality in the data? Does it feature more for some industries than for others? Is it more prevalent for localization or urbanization economies? The results show that agglomeration economies are not strictly unidirectional and that higher levels of productivity can induce growth in the scale of local urban and industrial environments. The paper discusses the difficulties that these issues pose for the estimation of agglomeration economies. [ABSTRACT FROM AUTHOR]

Abstract: Since at least 1935, vision researchers have used art stimuli to test human response to complex scenes. This is sensible given the “inherent interestingness” of art and its relation to the natural visual world. The use of art stimuli has remained popular, especially in eye tracking studies. Moreover, stimuli in common use by vision scientists are inspired by the work of famous artists (e.g., Mondrians). Artworks are also popular in vision science as illustrations of a host of visual phenomena, such as depth cues and surface properties. However, until recently, there has been scant consideration of the spatial, luminance, and color statistics of artwork, and even less study of ways that regularities in such statistics could affect visual processing. Furthermore, the relationship between regularities in art images and those in natural scenes has received little or no attention. In the past few years, there has been a concerted effort to study statistical regularities in art as they relate to neural coding and visual perception, and art stimuli have begun to be studied in rigorous ways, as natural scenes have been. In this minireview, we summarize quantitative studies of links between regular statistics in artwork and processing in the visual stream. The results of these studies suggest that art is especially germane to understanding human visual coding and perception, and it therefore warrants wider study. [Copyright &y& Elsevier]

Recently, statistical techniques have been used to assist art historians in the analysis of works of art. We present a novel technique for the quantification of artistic style that utilizes a sparse coding model. Originally developed in vision research, sparse coding models can be trained to represent any image space by maximizing the kurtosis of a representation of an arbitrarily selected image from that space. We apply such an analysis to successfully distinguish a set of authentic drawings by Pieter Bruegel the Elder from another set of well-known Bruegel imitations. We show that our approach, which involves a direct comparison based on a single relevant statistic, offers a natural and potentially more germane alternative to wavelet-based classification techniques that rely on more complicated statistical frameworks. Specifically, we show that our model provides a method capable of discriminating between authentic and imitation Bruegel drawings that numerically outperforms well-known existing approaches. Finally, we discuss the applications and constraints of our technique. [ABSTRACT FROM AUTHOR]

Fuel demand elasticities to determine consumer responses to tax increases or price shocks are typically based on aggregate data. The literature generally provides one elasticity estimate for each country, assuming similar response for all households. However, it is possible that different households can have different responses to the same stimuli depending on the household characteristics. Assuming a single elasticity for all households may fail to capture the detailed distributional effect on different socio-economic groups, which is often needed to fully understand the impact of fuel tax measures. This paper presents results from a household level gasoline demand model which accommodates variation in price and income elasticity with increasing income as well as for different socio-economic characteristics in the USA. We find substantial heterogeneity in price and income elasticities based on demographic groupings and income groups. Results of a distributional analysis for a gasoline tax are also presented using the heterogeneous responses. [ABSTRACT FROM AUTHOR]

Abstract: The fuel demand literature provides a range of estimates of the long and short-run price and income elasticities of gasoline demand for different countries and states. These estimates can be very useful in predicting the overall impacts of policy approaches designed to reduce fuel consumption and to address concerns of carbon emissions or energy security. However, analysis of policy options based on elasticities that are homogenous across income groups provides no information about the relative distributional burden that may be faced by different sectors of the population. Different responses to the same change in price or income are likely to occur, dependent on both travel needs and income levels. This paper estimates gasoline demand elasticities for different income quintiles in the United States to test for heterogeneity in demand response. Group wise summary consumer expenditure data for 20 years is used to derive the elasticity estimates. The results show that the elasticities do vary across groups and follow a U-pattern from the lowest to the highest income quintile. The lowest income quintile is found to have the largest price elasticity. The lowest and the highest income quintiles appear to be statistically insensitive to any changes in income. The rebound effect also follows the U-pattern, with the highest rebound observed among the wealthiest households. Rural households appear to have lower price elasticity than households in urban areas. [Copyright &y& Elsevier]

Systems do not elect thermodynamic pathways on their own. They operate in tandem with their surroundings. Pathway selection and traversal require coordinated work and heat exchanges along with parallel tuning of the system variables. Previous research by the author (Reference [1]) focused on the information expressed in thermodynamic pathways. Examined here is how spectral entropy is a by-product of information that depends intricately on the pathway structure. The spectral entropy has proven to be a valuable tool in diverse fields. This paper illustrates the contact between spectral entropy and the properties which distinguish ideal from non-ideal gases. The role of spectral entropy in the first and second laws of thermodynamics and heat → work conversions is also discussed. [ABSTRACT FROM AUTHOR]

Abstract: A dynamic panel model is used to estimate the effect that fares, income and quality of service have on demand for a sample of 22 urban metros. The estimated price elasticity is −0.05 in the short run and −0.33 in the long run. The estimated long run income elasticity is small but positive (0.18), indicating that metros are perceived as normal goods. The quality of service elasticities are positive and substantially higher than the absolute value of fare elasticities. The implication is that quality of service improvements, rather than fare reductions, may be more effective in increasing metro patronage. [Copyright &y& Elsevier]

This article estimates urbanisation and localisation economies for two digit manufacturing and service industries. The analysis is based on estimation of a translog production-inverse input demand system using data on British firms. We use distance-based measures of localisation to test for the spatial transmission of externalities. We identify positive localisation economies for 13 of the 27 sectors examined. The results indicate that where localisation economies exist, they tend to attenuate fairly rapidly with distance. All localisation externalities are identified within a 10 kilometre radius of the firm. Positive elasticities of productivity with respect to urbanisation are identified for 14 sectors. The weighted average localisation elasticity for manufacturing industries is 0.03 and for services 0.01. The mean urbanisation elasticities are 0.07 and 0.19 respectively. [ABSTRACT FROM AUTHOR]

Two recent studies suggest that natural scenes and paintings show similar statistical properties. But does the content or region of origin of an artwork affect its statistical properties? We addressed this question by having judges place paintings from a large, diverse collection of paintings into one of three subject-matter categories using a forced-choice paradigm. Basic statistics for images whose caterogization was agreed by all judges showed no significant differences between those judged to be 'landscape' and 'portrait/still-life', but these two classes differed from paintings judged to be 'abstract'. All categories showed basic spatial statistical regularities similar to those typical of natural scenes. A test of the full painting collection (140 images) with respect to the works' place of origin (provenance) showed significant differences between Eastern works and Western ones, differences which we find are likely related to the materials and the choice of background color. Although artists deviate slightly from reproducing natural statistics in abstract art (compared to representational art), the great majority of human art likely shares basic statistical limitations. We argue that statistical regularities in art are rooted in the need to make art visible to the eye, not in the inherent aesthetic value of natural-scene statistics, and we suggest that variability in spatial statistics may be generally imposed by manufacture. [ABSTRACT FROM AUTHOR]