The Accident Externality from Driving

We estimate auto accident externalities (more specifically insurance externalities) using panel data on state-average insurance premiums and loss costs. Externalities appear to be substantial in traffic dense states: in California, for example, we find that a typical additional driver increases the total of other people's insurance costs by $2231 per year. In such states, an increase in traffic density dramatically increases aggregate insurance premiums and loss costs. In contrast, the accident externality per driver in low traffic states appears quite small. On balance, accident externalities are so large that a correcting Pigouvian tax could raise$45 billion annually in California alone, and over $140 billion nationally. The extent to which this externality results from increases in accident rates, accident severity or both remains unclear. It is also not clear whether the same externality pertains to underinsured accident costs like fatality risk.

Prediction in bilingual children: The missing piece of the puzzle

A wealth of studies has shown that more proficient monolingual speakers are better at predicting upcoming information during language comprehension. Similarly, prediction skills of adult second language (L2) speakers in their L2 have also been argued to be modulated by their L2 proficiency. How exactly language proficiency and prediction are linked, however, is yet to be systematically investigated. One group of language users which has the potential to provide invaluable insights into this link is bilingual children. In this paper, we compare bilingual children’s prediction skills with those of monolingual children and adult L2 speakers, and show how investigating bilingual children’s prediction skills may contribute to our understanding of how predictive processing works

Electron-phonon superconductivity in the ternary phosphides BaM2 P2 (M=Ni,Rh,and Ir)

This is the final version of the article. Available from American Physical Society via the DOI in this record.Ab initio plane-wave pseudopotential calculations of electronic and vibrational properties have been carried out for the ternary phosphides BaM2P2 (M=Ni,Rha and Ir) with a ThCr2Si2-type structure. The calculated electronic results show the metallic character of BaM2P2, and the plots of total and partial density of states of BaM2P2 exhibit strong hybridization between the d states of the M atom and the p states of the P atom below the Fermi energy. Differences in the phonon spectrum and density of states both in the acoustical and optical ranges for these compounds are presented and discussed. The Eliashberg spectral function for these compounds has been calculated by using a linear response approach based on the density functional theory. By integrating the Eliashberg spectral function, the average electron-phonon coupling parameter (λ) is determined to be 0.61 for BaNi2P2, 0.55 for BaIr2P2, and 0.43 for BaRh2P2. Using the calculated values of λ and the logarithmically averaged phonon frequency ωln the superconducting critical temperature (Tc) values for BaNi2P2,BaIr2P2, and BaRh2P2 are obtained to be 2.80, 1.97, and 0.70 K, respectively, which compare very well with their experimental values of 3.0, 2.1, and 1.0 K.This work was supported by the Scientific and Technical Research Council of Turkey (TÜBİTAK) (Project Number MFAG-114F192). Some of the calculations for this project were carried out using the computing facilities on the Intel Nehalem (i7) cluster (ceres) in the School of Physics, University of Exeter, United Kingdom

Duration of patients’ visits to the hospital emergency department

Background Length of stay is an important indicator of quality of care in Emergency Departments (ED). This study explores the duration of patients’ visits to the ED for which they are treated and released (T&R). Methods Retrospective data analysis and multivariate regression analysis were conducted to investigate the duration of T&R ED visits. Duration for each visit was computed by taking the difference between admission and discharge times. The Healthcare Cost and Utilization Project (HCUP) State Emergency Department Databases (SEDD) for 2008 were used in the analysis. Results The mean duration of T&R ED visit was 195.7 minutes. The average duration of ED visits increased from 8 a.m. until noon, then decreased until midnight at which we observed an approximately 70-minute spike in average duration. We found a substantial difference in mean duration of ED visits (over 90 minutes) between Mondays and other weekdays during the transition time from the evening of the day before to the early morning hours. Black / African American patients had a 21.4-minute longer mean duration of visits compared to white patients. The mean duration of visits at teaching hospitals was substantially longer than at non-teaching hospitals (243.8 versus 175.6 minutes). Hospitals with large bed size were associated with longer duration of visits (222.2 minutes) when compared to hospitals with small bed size (172.4 minutes) or those with medium bed size (166.5 minutes). The risk-adjusted results show that mean duration of visits on Mondays are longer by about 4 and 9 percents when compared to mean duration of visits on non-Monday workdays and weekends, respectively. Conclusions The duration of T&R ED visits varied significantly by admission hour, day of the week, patient volume, patient characteristics, hospital characteristics and area characteristics

First-principles investigation of superconductivity in the body-centred tetragonal LaRu2P2

© 2016 Informa UK Limited, trading as Taylor & Francis Group.We have investigated the ground state and electronic properties of LaRu2P2 in the ThCr2Si2 structure using a generalised gradient approximation of the density functional theory and the ab initio pseudopotential method. We find that the calculated electronic properties of LaRu2P2 exhibit three-dimensional rather than two-dimensional characteristics in spite of the apparent two dimensionality in its atomic structure. An interesting feature of the phonon dispersion curves is the phonon anomaly in the lowest transverse acoustic branch as well as the longitudinal acoustic branch. We have shown that these phonon anomalies give rise to large electron-phonon interaction, as is evident from the calculated Eliashberg spectral function α2) F(ω) By integrating this spectral function, the value of average electron-phonon coupling parameter is calculated to be 0.85, from which the superconducting critical temperature is estimated to be 3.74 K, in gratifying accord with its experimental value of 4.0 K.This work was supported by the Scientific and Technical Research Council of Turkey (TÜB˙ITAK) [project number MFAG-114F192]

Differentially Private Linear Optimization for Multi-Party Resource Sharing

This study examines a resource-sharing problem involving multiple parties that agree to use a set of capacities together. We start with modeling the whole problem as a mathematical program, where all parties are required to exchange information to obtain the optimal objective function value. This information bears private data from each party in terms of coefficients used in the mathematical program. Moreover, the parties also consider the individual optimal solutions as private. In this setting, the concern for the parties is the privacy of their data and their optimal allocations. We propose a two-step approach to meet the privacy requirements of the parties. In the first step, we obtain a reformulated model that is amenable to a decomposition scheme. Although this scheme eliminates almost all data exchanges, it does not provide a formal privacy guarantee. In the second step, we provide this guarantee with a locally differentially private algorithm, which does not need a trusted aggregator, at the expense of deviating slightly from the optimality. We provide bounds on this deviation and discuss the consequences of these theoretical results. We also propose a novel modification to increase the efficiency of the algorithm in terms of reducing the theoretical optimality gap. The study ends with a numerical experiment on a planning problem that demonstrates an application of the proposed approach. As we work with a general linear optimization model, our analysis and discussion can be used in different application areas including production planning, logistics, and revenue management

National Bureau of Economic Research

Abstract: Does a one percent increase in aggregate driving increase accident costs by more than one percent? Vickrey [1968] and Edlin [1999] answer yes, arguing that as a new driver takes to the road, she increases the accident risk to others as well as assuming risk herself. On the other hand, more driving could result in increased congestion, lower speeds, and less severe or less frequent accidents. We study the question with panel data on state-average insurance premiums and loss costs. We …nd that in high tra¢c density states, an increase in tra¢c density dramatically increases aggregate insurance premiums and loss costs. In California, for example, we estimate that a typical additional driver increases the total of other people’s insurance costs by $1271-2432. In contrast, the accident externality per driver in low tra¢c states appears quite small. On balance, accident externalities are so large that a correcting Pigouvian tax could raise$45 billion in California alone, and over $140 billion nationally. It is not clear the extent to which this externality results from increases in accident rates, accident severity or both. It is also not clear whether the same externality pertains to underinsured accident costs like fatality risk

Theoretical investigation of electron-phonon interaction in the orthorhombic phase of Mo2C

This is the author accepted manuscript. The final version is available from Elsevier via the DOI in this record We have studied the structural, electronic, elastic, mechanical, vibrational and electron-phonon interaction properties of Mo 2 C crystallizing in the simple orthorhombic ζ-Fe 2 N-type crystal structure by using the generalized gradient approximation of the density functional theory and the plane wave ab initio pseudopotential method. A critical assessment of the calculated electronic structure and density of states reveals that the bonding in this material is a combination of covalent, ionic and metallic in nature. The calculated values of the second order elastic constants signal its mechanical stability. An examination of the calculated Eliashberg spectral function reveals that Mo-related phonon modes couple strongly to electrons due to the significant presence of Mo d electrons at the Fermi energy. From the integration of this spectral function, the value of average electron-phonon coupling parameter is determined to be of the intermediate strength 0.709. Finally, the value of the superconducting critical temperature is calculated to be 7.37 K, in excellent accordance with its measured value of 7.30 K