published journal article

Association of Neighborhood Socioeconomic Disadvantage and Postpartum Readmission

Obstetrics & Gynecology

Publication Date

May 1, 2023

Author(s)

Jenna Meiman, William A. Grobman, David M. Haas, Lynn M. Yee, Jiqiang Wu, Becky McNeil, Jun Wu, Brian Mercer, Hyagriv Simhan, Uma Reddy, Robert Silver, Samuel Parry, George Saade, Courtney D. Lynch, Kartik K. Venkatesh

Abstract

We assessed whether neighborhood socioeconomic disadvantage, as measured by the Area Deprivation Index (ADI), was associated with an increased risk of postpartum readmission. This is a secondary analysis from nuMoM2b (Nulliparous Pregnancy Outcomes Study: Monitoring Mothers-To-Be), a prospective cohort of nulliparous pregnant individuals from 2010 to 2013. The exposure was the ADI in quartiles, and the outcome was postpartum readmission; Poisson regression was used. Among 9,061 assessed individuals, 154 (1.7%) were readmitted postpartum within 2 weeks of delivery. Individuals living with the most neighborhood deprivation (ADI quartile 4) were at increased risk of postpartum readmission compared with those living with the lowest neighborhood deprivation (ADI quartile 1) (adjusted risk ratio 1.80, 95% CI 1.11–2.93). Measures of community-level adverse social determinants of health, such as the ADI, may inform postpartum care after delivery discharge.

Suggested Citation
Jenna Meiman, William A. Grobman, David M. Haas, Lynn M. Yee, Jiqiang Wu, Becky McNeil, Jun Wu, Brian Mercer, Hyagriv Simhan, Uma Reddy, Robert Silver, Samuel Parry, George Saade, Courtney D. Lynch and Kartik K. Venkatesh (2023) “Association of Neighborhood Socioeconomic Disadvantage and Postpartum Readmission”, Obstetrics & Gynecology, 141(5), p. 967. Available at: 10.1097/AOG.0000000000005151.

working paper

Location and Transportation Strategies in Public Facility Planning

Publication Date

November 1, 1977

Author(s)

Andrew N. White

Working Paper

UCI-ITS-WP-77-8

Abstract

Public facility planning is currently viewed in terms of structuring a service delivery system for optimal provision. Because the spatial process of delivery has been neglected, however, the means of improving service utilization have been narrowly construed as locational in nature. Consequently, facility systems have been modeled and evaluated in terms of supply rather than use, and decentralization has been advocated to the exclusion of alternative spatial patterns. An expanded planning framework regards service delivery as a spatial interaction system and identifies location and transportation as complementary spatial strategies which enhance service utilization and widen the choice of facility pattern. Transportation strategies are more flexible, though, since they directly enhance travel behavior and service accessibility. Moreover, given present planning constraints, transportation strategies have a much wider role to play in improving the effectiveness of future public facility planning and spatial policy. 

Suggested Citation
Andrew N. White (1977) Location and Transportation Strategies in Public Facility Planning. Working Paper UCI-ITS-WP-77-8. Institute of Transportation Studies, Irvine. Available at: https://escholarship.org/uc/item/6sr9z05m.

published journal article

Refueling hydrogen fuel cell vehicles with 68 proposed refueling stations in California: Measuring deviations from daily travel patterns

International Journal of Hydrogen Energy

Suggested Citation
Jee Eun Kang, Tim Brown, Will W. Recker and G. Scott Samuelsen (2014) “Refueling hydrogen fuel cell vehicles with 68 proposed refueling stations in California: Measuring deviations from daily travel patterns”, International Journal of Hydrogen Energy, 39(7), pp. 3444–3449. Available at: 10.1016/j.ijhydene.2013.10.167.

research report

US household preferences for alternative-fuel vehicles: Results from a national survey

Publication Date

January 1, 2012
Suggested Citation
Jean-Daniel Saphores and Hilary Nixon (2012) US household preferences for alternative-fuel vehicles: Results from a national survey.

published journal article

Gauging the effectiveness of airline schedule buffers in reducing arrival delays

Journal of Air Transport Management

Publication Date

May 1, 2025

Author(s)

Jan Brueckner, Achim I. Czerny, Alberto A. Gaggero

Abstract

In a novel contribution to the literature on airline flight delays, this paper explores the effects of airline schedule buffers on arrival delays, showing that buffers reduce delays and are thus beneficial. The exercise relies on the approach followed in our previous work, which allows us to measure buffer sizes and flight delays by using government data on the flight sequences of individual aircraft. Our empirical results roughly match the predictions of an analytical model regarding the expected sizes of the buffer effects.

Suggested Citation
Jan K. Brueckner, Achim I. Czerny and Alberto A. Gaggero (2025) “Gauging the effectiveness of airline schedule buffers in reducing arrival delays”, Journal of Air Transport Management, 125, p. 102776. Available at: 10.1016/j.jairtraman.2025.102776.

conference paper

A freight transshipment network model for forecasting commodity and cyclic commercial vehicle flows

Proceedings of the 91st annual meeting of the transportation research board

Publication Date

January 1, 2012

Abstract

A freight forecast model that assigns commodity flows to cyclic commercial vehicles is proposed in this study. The commercial vehicles are formulated to traverse in cycles and include loading and unloading costs at zone centroids. Empty hauls can be tracked, as can transshipment flows by commodity type and by inbound and outbound modes. A linear programming formulation is proposed as well as nonlinear objectives for link and transshipment congestion. An inverse nonlinear programming approach using Karush-Kuhn-Tucker conditions is formulated to calibrate the congestion parameters of this model such that observed flow variables are optimal. Because the forward problem is convex and composed of only equality or non-negativity constraints, it can be readily solved with classical nonlinear optimization methods instead of treating the inverse problem as a nonlinear complementarity problem. The models are tested on a 6-node network with up to 54 transshipment activities. The model is shown to be sensitive to supply side changes on links and transshipment facilities or to fuel cost changes. The appendix includes an inverse traffic assignment problem using the inverse nonlinear programming method.

Suggested Citation
Joseph Y.J. Chow and Stephen G. Ritchie (2012) “A freight transshipment network model for forecasting commodity and cyclic commercial vehicle flows”, in Proceedings of the 91st annual meeting of the transportation research board, p. 30p.

published journal article

Motivating students to pursue transportation careers. Implementation of Service-Learning Project on Transit

Transportation Research Record

Publication Date

January 1, 2015
Suggested Citation
Sarah Hernandez and Stephen G. Ritchie (2015) “Motivating students to pursue transportation careers. Implementation of Service-Learning Project on Transit”, Transportation Research Record, 2480(1), pp. 30–37. Available at: 10.3141/2480-04.

published journal article

Point queue models: A unified approach

Transportation Research Part B: Methodological

Publication Date

July 1, 2015

Author(s)

Suggested Citation
Wen-Long Jin (2015) “Point queue models: A unified approach”, Transportation Research Part B: Methodological, 77, pp. 1–16. Available at: 10.1016/j.trb.2015.02.015.

published journal article

Physiological and affective responses to green space virtual reality among pregnant women

Environmental Research

Publication Date

January 1, 2023

Author(s)

Yi Sun, Fu Li, Tao He, Yaohan Meng, Jie Yin, Ilona S. Yim, Liyan Xu, Jun Wu

Abstract

Background Benefits of green spaces on stress reduction have been shown in previous studies. Most existing studies to date have focused on the general population. However, there is a lack of understanding of physiological mechanisms underlying the beneficial effects of green space among special populations, such as pregnant women. Objectives To examine physiological and affective responses to green space on stress recovery among pregnant women, using simulated green space exposure through virtual reality (VR). Methods We recruited 63 pregnant women between 8 and 14 weeks’ gestational age for a laboratory experiment. Participants were randomly assigned to view one of three, 5-min, VR videos of an urban scene with different green space levels (i.e., non-green, moderate, and high) after a laboratory stressor, the Trier Social Stress Test. Physiological stress responses were measured via changes in blood pressure, heart rate, skin conductance level, salivary alpha-amylase, and salivary cortisol. Affective response was measured using the Positive and Negative Affect Scale. Results We found that visual exposure to a green space environment in VR was associated with both physiological and affective stress reduction among pregnant women, including lower systolic blood pressure [-4.6 mmHg, 95% confidence interval (CI): −8.8, −0.4], reduced salivary alpha-amylase concentration (−1.2 ng/ml, 95% CI: −2.2, −0.2), improved overall positive affect (score: 6.6, 95% CI: 0.3, 13.0) and decreased negative affect of anxiety (score: −2.6, 95% CI: −5.19, −0.04) compared to non-green space environment. Exposure to high green space environment in park-like setting had the strongest impacts on stress recovery. Conclusion This study demonstrated that virtual green space exposure could effectively ease stress and improve mental health and well-being during pregnancy. Even a short immersion in VR-based green space environment may bring health benefits, which has significant implications for pregnant women when access to an actual nature may not be possible.

Suggested Citation
Yi Sun, Fu Li, Tao He, Yaohan Meng, Jie Yin, Ilona S. Yim, Liyan Xu and Jun Wu (2023) “Physiological and affective responses to green space virtual reality among pregnant women”, Environmental Research, 216, p. 114499. Available at: 10.1016/j.envres.2022.114499.