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Cover page of Integration and calibration of UBCSAND model for drained monotonic and cyclic triaxial compression of aggregates

Integration and calibration of UBCSAND model for drained monotonic and cyclic triaxial compression of aggregates

(2023)

We report on results from triaxial drained monotonic and cyclic compression tests for four different aggregates (gabbro, limestone, demolished concrete, steel slag), and discuss the applicability of UBCSAND model for simulating the relevant non-linear stress-strain curves. First, UBCSAND is integrated analytically for the elastic and plastic volumetric and deviatoric strains, leading to a pair of novel closed-form solutions expressed in terms of hypergeometric functions. These solutions are inherently free of numerical errors and can be used for the evaluation of results from numerical integration. Second, three calibration techniques for the model parameters are presented and compared: (1) a graphical “chart” solution based on results from forward numerical simulations; (2) a numerical approach based on minimization of residuals; and (3) an informed trial-and-error approach based on the analytical solution. Errors in numerical integration of the model are explored by comparing the analytical solution against results from an Euler integration. Variations in the calibrated parameters are discussed for drained monotonic and cyclic triaxial loading considering different types of aggregates.

Cover page of Discovery of a novel sub-lineage of multi-drug resistant Shigella flexneri in Southern California.

Discovery of a novel sub-lineage of multi-drug resistant Shigella flexneri in Southern California.

(2023)

Clustered outbreaks of multi-drug resistant (MDR) Shigella are on the rise among men who have sex with men (MSM). Identification of MDR sub-lineages is critical for clinical management and public health interventions. Here, we describe a novel MDR sub-lineage of Shigella flexneri isolated from an MSM patient without a travel history in Southern California. Detailed genomic characterization of this novel strain would serve as a reference to aid monitoring and future outbreak investigation of MDR Shigella among MSM.

Cover page of Networking community health workers for service integration: role of social media.

Networking community health workers for service integration: role of social media.

(2023)

Community health workers (CHW) can play an active role in providing integrated HIV and harm reduction services. We used social media to create a virtual network among Vietnamese CHW. This paper reports CHW's social media engagement and the relationships with other work-related indicators. Sixty CHW participated in an intervention for integrated HIV/drug use service delivery. Following two in-person sessions, Facebook groups were established for CHW to share information, seek consultation, and refer patients. CHW's levels of online engagements were tracked for six months and linked to their service provision confidence, interaction with patients and other providers, and job satisfaction. The CHW made 181 posts, which received 557 comments and 1,607 reactions during the six months. Among the 60 CHW, 22 (36.6%) had three or more posts, 19 (31.7%) had one or two posts, and 19 (31.7%) had no post. Comparing the baseline and 6-month follow-up data, we observed that those who posted three or more times showed better service provision confidence (p = 0.0081), more interaction with providers in other settings (p = 0.0071), and higher job satisfaction (p = 0.0268). Our study suggests using social media to engage CHW in virtual communications to improve service provision in communities.

Cover page of What are the indications and survivorship of tumor endoprosthetic reconstructions for patients with extremity metastatic bone disease?

What are the indications and survivorship of tumor endoprosthetic reconstructions for patients with extremity metastatic bone disease?

(2023)

Background and objectives

Given advances in therapies, endoprosthetic reconstruction (EPR) in metastatic bone disease (MBD) may be increasingly indicated. The objectives were to review the indications, and implant and patient survivorship in patients undergoing EPR for MBD.

Methods

A review of patients undergoing EPR for extremity MBD between 1992 and 2022 at two centers was performed. Surgical data, implant survival, patient survival, and implant failure modes were examined.

Results

One hundred fifteen patients were included with a median follow-up of 14.9 months (95% confidence interval [CI]: 9.2-19.3) and survival of 19.4 months (95% CI: 13.6-26.1). The most common diagnosis was renal cell carcinoma (34/115, 29.6%) and the most common location was proximal femur (43/115, 37.4%). Indications included: actualized fracture (58/115, 50.4%), impending fracture (30/115, 26.1%), and failed fixation (27/115, 23.5%). Implant failure was uncommon (10/115, 8.7%). Patients undergoing EPR for failed fixation were more likely to have renal or lung cancer (p = 0.006).

Conclusions

EPRs were performed most frequently for renal cell carcinoma and in patients with a relatively favorable survival. EPR was indicated for failed previous fixation in 23.5% of cases, emphasizing the importance of predictive survival modeling. EPR can be a reliable and durable surgical option for patients with MBD.

Cover page of Perceptions of School Climate Shape Adolescent Health Behavior: A Longitudinal Multischool Study.

Perceptions of School Climate Shape Adolescent Health Behavior: A Longitudinal Multischool Study.

(2023)

Background

Adolescent behaviors and academic outcomes are thought to be shaped by school climate. We sought to identify longitudinal associations between school climate measures and downstream health and academic outcomes.

Methods

Data from a longitudinal survey of public high school students in Los Angeles were analyzed. Eleventh-grade health and academic outcomes (dependent variables, eg, substance use, delinquency, risky sex, bullying, standardized exams, college matriculation), were modeled as a function of 10th-grade school climate measures (independent variables: institutional environment, student-teacher relationships, disciplinary style), controlling for baseline outcome measures and student/parental covariates.

Results

The 1114 student respondents (87.8% retention), were 46% male, 90% Latinx, 87% born in the United States, and 40% native English speakers. Greater school order and teacher respect for students were associated with lower odds of multiple high risk behaviors including 30-day alcohol use (odds ratio [OR] 0.81; 95% confidence interval [CI] [0.72, 0.92] and OR 0.73; [0.62, 0.85]) and 30-day cannabis use (OR 0.74; [0.59, 0.91] and OR 0.76; [0.63, 0.92]). Neglectful disciplinary style was associated with multiple poor health and academic outcomes while permissive disciplinary style was associated with favorable academic outcomes.

Implications for school health policy, practice, and equity

School health practitioners may prospectively leverage school environment, teacher-student relationships, and disciplinary style to promote health and learning.

Conclusions

Our findings identify specific modifiable aspects of the school environment with critical implications for life course health.

Cover page of Disparity in Obesity and Hypertension Risks Observed Between Pacific Islander and Asian American Health Fair Attendees in Los Angeles, 2011-2019.

Disparity in Obesity and Hypertension Risks Observed Between Pacific Islander and Asian American Health Fair Attendees in Los Angeles, 2011-2019.

(2023)

Introduction

The Pacific Islander American population is understudied due to being aggregated with Asian Americans. In this study, we conduct a comparative analysis of directly measured body mass index (BMI), body fat percentage (%BF), and blood pressure (BP) between Pacific Islander Americans and Asian Americans from health screenings in Los Angeles, California. We hope to reveal intra-APIA health disparities masked by this data aggregation.

Methods

We analyzed BMI, %BF, and BP that were objectively measured by trained personnel at health screenings in Los Angeles between January 2011 and December 2019. We performed multivariable multinomial logistic regression models with obesity and hypertensive categories as outcome variables and ethnicity as the primary independent variable of interest. Models controlled for year of visit, participant age, sex, income, education level, years living in the USA, employment status, English proficiency, regular doctor access, and health insurance status.

Results

A total of 4,832 individuals were included in the analysis. Multivariable analyses revealed that Pacific Islander participants were at significantly higher risks for being classified as obese compared with all Asian American subgroups studied, including Chinese, Korean, Thai, Vietnamese, Filipino, and Japanese. Pacific Islanders also exhibited significantly lower predicted probability of having a normal blood pressure compared with Chinese and Thai participants. Some variation between Asian subgroups were also observed.

Conclusions

Pacific Islander participants had higher risk of several sentinel health problems compared to Asian American participants. Disaggregation of PI Americans from the APIA umbrella category in future studies is necessary to unmask the critical needs of this important community.

Cover page of Machine learning-based predictive control of nonlinear time-delay systems: Closed-loop stability and input delay compensation

Machine learning-based predictive control of nonlinear time-delay systems: Closed-loop stability and input delay compensation

(2023)

The purpose of this work is to study machine-learning-based model predictive control of nonlinear systems with time-delays. The proposed approach involves initially building a machine learning model (i.e., Long Short Term Memory (LSTM)) to capture the process dynamics in the absence of time delays. Then, an LSTM-based model predictive controller (MPC) is designed to stabilize the nonlinear system without time delays. Closed-loop stability results are then presented, establishing robustness of this LSTM-based MPC towards small time-delays in the states. To handle input delays, we design an LSTM-based MPC with an LSTM-based predictor that compensates for the effect of input delays. The predictor is used to predict future states using the process measurement, and then the predicted states are used to initialize the LSTM-based MPC. Stabilization of the time-delay system with both state and input delays around the steady state is achieved through the featured design. The approach is applied to a chemical process example, and its performance and robustness properties are evaluated via simulations.

Cover page of A pragmatic feasibility trial of the Primary Care Intervention for PTSD: A health service delivery model to reduce health disparities for low-income and BIPOC youth.

A pragmatic feasibility trial of the Primary Care Intervention for PTSD: A health service delivery model to reduce health disparities for low-income and BIPOC youth.

(2023)

Objective

This study is a non-randomized pragmatic trial to assess the feasibility and acceptability of the Primary Care Intervention for Posttraumatic stress disorder (PCIP) (Srivastava et al., 2021), an Integrated Behavioral Health Care treatment for PTSD in adolescents.

Method

Following routine clinic procedures, youth who were suspected of having trauma-related mental health symptoms were referred by their primary care providers to integrated care social workers for evaluation. The integrated care social workers referred the first 23 youth whom they suspected of having PTSD to the research study. Twenty youth consented to the study and 19 completed the pre-assessment (17 female; mean age = 19.32, SD = 2.11; range 14-22 years). More than 40% identified as Black and a third as Hispanic/Latinx. PCIP mechanisms and clinical outcomes were assessed pre- and post-treatment, and at one-month follow-up. Participants and therapists completed post-treatment qualitative interviews to assess feasibility and acceptability, and treatment sessions were audio recorded to assess fidelity.

Results

Findings suggest high acceptability, satisfaction, and feasibility of the PCIP delivered in "real-life" safety net pediatric primary care. Integrated care social workers had high treatment fidelity. Despite the small sample size, there was significant improvement in symptom scores of anxiety (g = 0.68, p = 0.02) and substance use (g = 0.36, p = 0.04) from pre to post, and depression symptoms (g = 0.38, p = 0.04) from pre to follow-up. Qualitative data from patients who completed exit interviews and integrated social workers indicated high satisfaction with the treatment, with some participants reporting that the integrated intervention was more acceptable and less stigmatizing than seeking mental health care outside of primary care.

Conclusions

The PCIP may improve treatment engagement and access for vulnerable youth. Promising findings of high acceptability, feasibility, and initial clinical effectiveness suggest that PCIP warrants larger-scale study as part of routine care in pediatric integrated care.

Cover page of OCCUPY WALL STREET AND THE ECONOMIC IMAGINATION

OCCUPY WALL STREET AND THE ECONOMIC IMAGINATION

(2023)

This article explores the making of an expansive and expanding economic imagination in disparate Occupy sites—the Alternative Banking working group of Occupy Wall Street, the daily life of lists in Liberty Square, née Zuccotti Park, and the work of Strike Debt. In particular, I focus on transformative possibility in unanticipated places. Where anthropology and critical theory have often sought out capitalism’s otherwises for inspiration and potential, the expansion of the economic imagination I trace here suggests that the centers constitute zones of possibility as well. I aim to show not only the conditions of possibility for a certain kind of imaginative work in the dense and seemingly definitive spaces of financial expertise but also a remarkable, and largely unrecognized, contemporary conversation around the future of banking, foreclosures, and democratized finance.