University of Michigan–Flint

Zedini E., Ata Y., Al-Sallami F.M., Rajbhandari S.

Kim W., Kim J., Cho H., Gillis K.

Individuals facing intimate partner problems (IPP) often experience mental health issues, including suicidal thoughts and behaviors. Immigration status may increase risk due to the stress of acculturation and barriers to health care affecting immigrants. This study aims to identify patterns of risk factors among immigrants who died by suicide while experiencing IPP and explore variations in patterns by sociodemographic characteristics and suicide contexts. Data includes 17 waves of the NVDRS from 2003 to 2019, which includes 3,177 immigrants facing IPP. Latent class analysis identified distinct groups based on their mental health status, substance use, and treatment history preceding suicide. Variations by demographic and suicidal contexts across groups were subsequently analyzed. Three-class solutions emerged: the group with reports of mental health problems (MH; 26.6%), the group with alcohol problems and substance use (AS; 6.5%), and the group that had neither (minor problems, MIN; 66.9%). The MH group comprised more females, Asians, and individuals with a college education, while the AS group had more males, Hispanics, and individuals with a high school education or less. The MH group tended to use poisoning as a suicide method more, whereas the MIN group used firearms more. The MH group also exhibited the highest prevalence of suicide attempts. In addition, the MH and AS groups had a history of suicidal thoughts and disclosed their suicidal ideation more than the MIN group. These findings underscore the distinct risk factors experienced by immigrants with IPP, associated with their demographic and suicidal event characteristics precipitating their suicidality, suggesting opportunities for targeted prevention efforts to mitigate such suicides.

Althoen S.C., Schilling K.

Rodriguez K.M., Palmieri-Smith R.M., Krishnan C.

Background: Diminished corticospinal excitability is theorized to contribute to poor quadriceps function after anterior cruciate ligament (ACL) reconstruction. Operant conditioning of the motor evoked torque (MEPTORQUE) is a promising approach capable of improving corticospinal excitability. However, it is unknown whether increasing corticospinal excitability can improve quadriceps function after a short-term operant conditioning intervention in patients with reconstructed ACL. Hypothesis: After ACL reconstruction, patients would demonstrate increases in quadriceps strength, voluntary activation, and corticospinal excitability after a 2-week operant conditioning intervention. Study Design: Randomized controlled clinical trial. Level of Evidence: Level 1. Methods: A total of 22 patients with reconstructed ACL were randomized into 1 of 2 groups: group 1 received 2 weeks of operant conditioning training on the reconstructed leg to improve their transcranial magnetic stimulation (TMS)-elicited MEPTORQUE responses (COND); group 2 received 2 weeks of TMS only (SHAM-COND). Quadriceps strength, voluntary activation, and corticospinal excitability on the reconstructed leg were evaluated before and after the 2-week intervention. Within-session changes in corticospinal excitability were also evaluated during the training sessions. Results: The COND group demonstrated a significantly higher within-session percent increase in MEPTORQUE during training compared with the SHAM-COND group, paralleled by a significant increase in corticospinal excitability after the 2-week intervention. In addition, quadriceps strength and voluntary activation improved on the reconstructed leg after the 2-week intervention, regardless of group. Conclusion: Operant conditioning training can elicit improvements in corticospinal excitability after ACL reconstruction; however, improvements in quadriceps strength and voluntary activation seem not to be attributed solely to operant upconditioning training. Clinical Relevance: Operant conditioning is a promising approach to improve corticospinal excitability after ACL reconstruction. However, optimizing the delivery of operant conditioning protocols by potentially increasing the dosage of operant conditioning and intervening earlier after surgery may be needed to translate these changes to improvements in quadriceps function.

Shang S., Zedini E., Alouini M.

Bhuiyan M.Z., Khanafer K., Rafi E.I., Shihab M.S.

Additive manufacturing (AM) or 3D printing technology creates a tangible object by adding successive layers of materials. Nowadays, 3D printing is used for developing both metal and non-metal products. In the advancement of 3D printing technology, material specimen design, modification, and testing become very simple, especially for non-metal materials, such as hyperelastic, thermoplastic, or rubber-like materials. However, proper material modeling and validation are required for the analysis of these types of materials. In this study, 3D printed poly lactic acid (PLA+) material behavior is analyzed numerically for validation in the counterpart of experimental analysis to evaluate their behavior in both cases. The specimen was designed in SolidWorks by following ASTM D638 dimension standards with proper infill densities and raster angle or infill orientation angle. These infill layer densities and angles of orientation play an important role in the mechanical behavior of the specimen. This paper aims to present a numerical validation of five infill densities (20%, 40%, 60%, 80%, and 100%) for a ±45-degree infill angle orientation by incorporating a nonlinear hyperelastic model. Results indicate that infill densities affect the mechanical behavior of PLA+ material. The result also suggested that neo-Hookean and Mooney–Rivlin are the best-fitted hyperelastic material models for these five separate linear infill densities. However, neo-Hookean is easier to analyze, as it has only one parameter and a new equation is developed in this study for determining the parameter for different infill densities.

Yorke A., Trojanowski S., Hurlburt S., Gehrke J.

Gasmi I., Neji S., Smiti S., Soui M.

Credit risk assessment has drawn great interests from both researcher studies and financial institutions. In fact, classifying an applicant as defaulter or non-defaulter customer helps banks to make a reasonable decision. The classification of applicants is based on a set of historical information of past loans. Data sets for analysis may include different features, many of which may be irrelevant to the decision making process. Keeping irrelevant features or leaving out relevant ones may be harmful, causing generation of poor quality patterns that may lead to confusion decision. Determining an appropriate set of predictors is an important challenge in credit risk prediction research which guarantees better decision-making. It is the task of searching the smallest subset of features that provide the highest accuracy and comprehensibility. Thus, this study proposes feature selection-based classification model on credit risk assessment. To this end, five algorithms are applied, Speed-constrained Multi-objective PSO (SMPSO), Non-dominated Sorting Algorithm (NSGA-II), Sequential Forward Selection (SFS), Sequential Forward Floating Selection (SFFS), and Random Subset Feature Selection (RSFS). The selected subset is evaluated based on three classifiers K-Nearest Neighbors (KNN), Support Vector Machine (SVM) and Artificial Neural Network (ANN). Our proposed model is validated using three real-world credit datasets. The obtained results confirm the efficiency of SMPSO-KNN model to select the most significant features and provide the highest classification accuracy compared to existing models.

Ranganathan R., Lee M., Krishnan C.

Zedini E., Ata Y., Kammoun A., Alouini M.

Runnalls B.A., Blume B.D., Huang J.L., Wang Z., Ford J.K.

ABSTRACTWhen employees begin a new job in a competitive sales environment, they have a lot to learn in a short period of time. Most organizations incorporate an employee orientation and formal training, but newcomers also learn informally while on the job. We examine the impact of informal field‐based learning (IFBL) on individual outcomes of 242 newcomer sales employees. We investigate how supervisor empowerment interacts with employees' goal orientation to impact IFBL, which serves as a conduit to further influence training transfer and employee outcomes (i.e., supervisor‐rated performance, promotion, and turnover). Results demonstrate that IFBL promotes formal training transfer, which influences newcomers subsequent job performance, promotion, and turnover. We also found that supervisor empowerment has an indirect effect on employee promotion and turnover sequentially through IFBL, training transfer, and performance, and this indirect effect is moderated by employee goal orientation. Practical implications for leveraging supervisor empowerment and tailoring support based on employee goal orientation are discussed.

Ben Mrad A., O. Thiombiano A.M., Mkaouer M.W., Hnich B.

Identifying effective methods for automatic method renaming after code modifications is crucial for maintaining developer productivity and enhancing the performance of source code analysis tools. In this study, we focus on benchmarking the effectiveness of the ChatGPT large language model (LLM) in predicting new method names after code modifications. Leveraging a dataset of method code snippets along with their original and modified names, we conducted experiments on 116 samples to assess the prediction accuracy of ChatGPT. Using Jaccard similarity as the metric, we varied the similarity threshold to evaluate the classification performance of predicted names. However, the Jaccard similarity does not retain the magnitude or direction of the vectors, reflecting the strength and polarity of the similarity. In addition, it ignores the order and context of the words, which results in missing potential syntactic or semantic variations. To solve this problem, we propose another validation process which not only detects whether or not an LLM captured semantic changes of a method, but also its structural changes in order to be able to generate a suitable name for this given method. Our results indicate that ChatGPT achieves a high success rate in predicting method names, obtaining 98% (Resp. 94%) when the threshold is set to 0.5 for the Cosine (resp. Jaccard) similarity. For a threshold of 1 (maximum similarity), ChatGPT maintains a notable performance with 49% (Resp. 74%) Cosine (resp. Jaccard) similarity. This demonstrates the potential of ChatGPT for automating method renaming tasks in software development workflows.

Frank H., Sanabria-Pulido P., Douglas C., Scutelnicu Todoran G., Rodriguez-Plesa E., Hoermann S., Cheng S.

Goldberg A., Burkhardt S., Norris H., Garber J., Little N., Kendall J., Sucic J.

Abstract Deficits in walking speed are associated with poor health outcomes in older adults. The alpha-actinin-3 gene (ACTN3) harbors the R577X polymorphism, which influences muscle function and physical performance in older adults. Fear of falling (FOF) is associated with gait, mobility and physical performance deficits in older adults. Our objective was to determine if effects of FOF on fast gait speed (FGS) are associated with ACTN3 genotype, to identify individuals based on ACTN3 genotype at risk for greatest declines in FGS with onset of FOF. Older adults (N=168, female=61.3%, mean age 72.8 years, range 65-85 years) attended a study visit at which demographic, self-rated health (SRH) and FOF information was collected, and 10-meter FGS was tested. Saliva was obtained for ACTN3 genotyping. Multiple regression evaluated variance in FGS explained by FOF, RR genotype (present/absent), and interaction of FOF with RR genotype, controlling for age, sex and SRH. The final regression model explained 36.9% of FGS variance (p<.001). FOF was a significant predictor (β=-.163; p=.026) of FGS. RR genotype did not independently predict FGS (β=.103; p=.161), but was interactively with FOF a significant predictor (β=-.181; p=.024) of FGS. The effect of FOF on FGS was greater in individuals with RR genotype than in the RX/XX genotype subgroup (partial eta squared 0.083 and 0.030 respectively). The significant FOF x RR genotype interaction suggests that effects of FOF on FGS vary based on ACTN3 genotype. Individuals with RR genotype (compared to the RX/XX subgroup) may experience greater FGS declines with onset of FOF.

Karczewski H.A., Blackwood J.

Background/Objectives: Neighborhood walkability is the extent to which built and social environments support walking. Walkability influences older adults’ participation in outdoor physical activity. Identifying factors that influence physical therapists’ (PTs) decisions about prescribing outdoor walking is needed, especially for those who are aging in place. The purpose of this study is to describe the neighborhood walkability knowledge, perceptions, and assessment practices of PTs who work with community-dwelling older adults. Methods: A cross-sectional survey was sent via email to 5,000 PTs nationwide. The 40-item survey assessed walking prescriptions, walkability perceptions and assessments, and gathered demographic data. Categorical variables were compared using Chi-square analyses. Results: Using a total of 122 PTs who worked in outpatient geriatric physical therapy settings, a significant difference was found between perceptions of whether PTs should assess walkability and whether they actually assess walkability (χ2 = 78.7, p < .001). Decisions to prescribe outdoor walking were influenced by the availability (n = 79, 64.8%) and maintenance (n = 11, 9.0%) of sidewalks, crime (n = 9, 7.4%), terrain (n = 7, 5.7%), and aesthetics (n = 6, 4.9%). Objective walkability measures were not used by the respondents. Conclusion: When considering the assessment of walkability, PTs prioritize the built environment over the social environment. Although most believe it is the responsibility of the PT to assess walkability, most do not. Significance/Implications: Assessment of walkability may allow PTs to identify barriers and make more informed recommendations concerning outdoor walking for older adults. Objective measures are available for PTs when prescribing outdoor walking.