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In addressing limitations of conventional ground support measurement, a novel optical strain sensing technique is presented that is capable of measuring strain at increments as low as 0.65 mm along the entirety of an optical sensor affixed to a support element. The technique considers monitoring three sensing lengths along the profile of a fully grouted rock bolt element using a single optical fiber, which, in turn, allows the derivation of both the principle strain and principle strain direction along the bolt. A series of three experiments, which include: symmetric bending, combined axial load and bending, and double shear loading are presented and highlight the potential of the technique to capture bolt behaviour under such generalized rock bolt loading conditions. Analogized as a distributed strain rosette, the optical technique can distinguish both the coaxial and bending induced constituents of the total strain in the bolt regardless of load orientation. [ABSTRACT FROM AUTHOR]

Objective: Previous literature has studied the cognitive processes that contribute to performance on the Stroop interference condition in adults and found that the Stroop task performance (i.e., color-word interference) is comprised of multiple cognitive skills, including speed of visual search, working memory, and conflict monitoring (Perianez et al. 2020). However, the relationship of these cognitive processes to Stroop interference in youth remains understudied. Moreover, no studies have examined the contribution of effort measurement to the interference condition in healthy youth. Participants and Methods: Golden Stroop Test interference performance was examined in healthy youth athletes (n=174) aged 8-16 years (mean age=12.07) who participated in a baseline neuropsychological evaluation as part of a clinical research program on sports concussion. Predictor variables included speed of visual search, working memory, processing speed, verbal fluency effort (i.e., validity tests), visuospatial abilities, visual processing, and executive functioning skills such as cognitive flexibility and reasoning. Results: Speed of visual search as measured by Trail Making Test visual scanning time (p<0.00), and effort as measured by Reliable Digit Span and Trail Making Test ratio (p=0.03; p<0.00, respectively) significantly contributed to Stroop interference performance in healthy youth. We provided three validity measures; however, only those requiring higher-order cognitive processes predicted Stroop performance: Reliable Digit Span (p=0.03) and the Trail Making Test ratio (p<0.00). The standalone validity measure (TOMM) was not a significant predictor of Stroop performance (p>0.05). Conclusions: In contrast to adults, working memory and processing speed did not significantly predict Stroop performance, while visual search speed did predict Stroop interference. Furthermore, two embedded validity indicator (EVI) measures predicted Stroop interference, in contrast to a standalone validity measure requiring lower cognitive processes, which did not predict Stroop performance. Therefore, EVI's that include an executive functioning component may not accurately represent effort in youth, perhaps due to their less developed executive functioning relative to adults (Lezak et al., 2012; Shanmugan & Satterthwaite, 2017). Overall, understanding the cognitive processes contributing to Stroop performance in healthy youth will allow clinicians to better detect deficits in those cognitive processes and understand how they may impact Stroop performance. This would lead to a better understanding of executive functioning and the accurate measurement of effort in healthy youth. [ABSTRACT FROM AUTHOR]

Objective: Performance validity testing (PVT) is important in neuropsychological evaluations to ensure accurate interpretation of performance. While research shows children pass PVTs with adult cut-offs, PVTs are more commonly used with adults (Lippa, 2018). The Test of Memory Malingering (TOMM), a standalone PVT, is commonly used with adults and children (DeRight & Carone, 2015). The Reliable Digit Span (RDS), an embedded PVT derived from the Digit Span subtest of the Wechsler Intelligence Scales (Wechsler Intelligence Scale for Children-4th Edition, WISC-IV; Wechsler, 2003), is less commonly used with children (DeRight & Carone, 2015). RDS cut-off scores are associated with an increased rate of false positives in children, indicating mixed results regarding the clinical utility in pediatric populations (Welsh et al., 2012). Research shows that youth with a history of concussion (HOC) may demonstrate suboptimal effort for many reasons (e.g., external incentives, boredom, pressure), thus highlighting the need to investigate the utility of PVTs in this population (Araujo et al., 2014; DeRight & Carone, 2015). The present study aimed to examine the clinical utility of RDS in detecting poor effort on the TOMM in youth athletes with a HOC. Participants and Methods: Participants included 174 youth athletes aged 8 to 18 (20.1% female; 42.5% people of color (POC)) who completed a baseline neuropsychological battery that included the TOMM and WISC-IV Digit Span. Of the sample, 29 youth athletes reported a HOC (13.8% female; 37.9 POC). RDS was calculated for each Digit Span administration, and sensitivity (SN) and specificity (SP) were calculated for RDS when invalid performance was operationalized by a more stringent cut-off score of <49 to increase the SN of the TOMM Trial 1 (Stenclik et al., 2013). Receiver operator characteristics (ROC) curve analysis determined whether RDS performance accurately predicted participants' performance on the TOMM. Results: The ROC curve analysis resulted in an area under the curve (AUC) of just 0.427 for RDS. A cut-off score of <7 (as suggested by Kirkwood et al. (2011)) for RDS results in 100% SN, 8.3% SP, 5% positive predictive validity (PPV), and 95% negative predictive validity (NPV). However, a cut-off score of <9 for RDS results in 75% SN, 15% SP, 25% PPV, and 75% NPV. Conclusions: Little research shows the utility of different PVTs predicting children's performance on other PVTs, despite evidence that children with a HOC are vulnerable to variable or insufficient effort (Araujo et al., 2014; DeRight & Carone, 2015). In a sample of 29 youth athletes with a HOC, RDS predicted TOMM performance at rates worse than chance. While RDS has advantages as an embedded PVT, its limited ability to predict performance on a standalone PVT suggests interpreting with great caution. These findings highlight the importance of implementing multiple PVTs throughout testing to ensure accurate findings and interpretations, particularly in youth with a HOC. The small sample size is a limitation that possibly impacted the ability of RDS to predict TOMM performance. Further research is needed to understand the utility of RDS as a predictor of PVT performance in different populations. Replication of these findings with a larger sample size is needed to provide confirmatory evidence of poor predictive performance of the RDS. [ABSTRACT FROM AUTHOR]

A high spatial resolution distributed optical fiber strain sensing technology is demonstrated to advance the assessment of support element behaviour during in-situ pull tests. A technique to instrument typical tendon support elements with a fiber optic sensor is discussed and was trialed at an underground salt mine through a series of pull tests on instrumented rebar elements. It is shown that a continuous strain profile can be measured along the length of a support element under pull test load, which, in turn, allows the interfacial shear stress distribution and deformation of the support element to be resolved. In comparison to load and displacement measurements solely at the support element head, which is what is traditionally reported for in-situ pull tests, the optical fiber strain sensor is found to provide significantly more insight into the mechanistic behaviour of the support element by readily measuring highly variable strain distributions and by quantifying the load development length of the support element. The sensor arrangement allowed the conventional handling and installation procedures to be followed without any implication to the integrity of the sensor. Accordingly, an instrumented reinforcement element can be installed with minimal interruption to on-going mining/construction procedures at the given project. • Distributed optical fiber strain sensing is used to augment the in-situ pull test. • A fiber optic sensor instrumenting procedure is discussed. • Instrumented support elements are installed and pull tested in an underground mine. • Coaxial strain distributions are measured along rebar rock bolts in-situ. • Support element bond behaviour is quantified and compared using various sensors. [ABSTRACT FROM AUTHOR]

Objective: The Test of Memory Malingering (TOMM) is a performance validity test (PVT) that aims to assess whether participants are giving adequate effort to perform well on tasks of memory performance (Tombaugh, 1996). Other PVTs, specifically the Forced Choice Recognition Trial in the California Verbal Learning Test, have shown that even single errors may indicate invalid performance (Erdodi et al., 2018). Finally, youth are often understudied in the PVT literature, and athletes are at increased risk of invalid performance on baseline testing due to many wanting to return to play following concussion (Erdal, 2012). Therefore, the objective of the current study is to examine whether single errors on TOMM Trial 1 are indicative of lower, and possibly invalid, cognitive performance in a youth sample, given that cognitive performance declines with even small decreases in effort (Green, 2007). Participants and Methods: Healthy youth athletes (n=174) aged 8-16 years (M=12.07) completed the TOMM as well as other neuropsychological measures during baseline neuropsychological evaluation in a clinical research program for sports concussion. Independent samples t-tests compared youth athletes who scored 49 points on the TOMM (n=28) to youth athletes who scored a perfect 50 (n=50) across several groupings of neuropsychological measures. Participants who scored less than 49 or who didn't complete the TOMM were excluded from the analyses. Results: Participants scoring 50/50 on TOMM Trial 1 scored significantly higher on Stroop Color Naming task (p=0.036), Verbal Learning Delayed task from the second edition of the Wide Range Assessment of Learning and Memory (WRAML-2, p=0.018), and Letter Number Sequencing task from the Weschler Intelligence Scale for Children (WISC-IV, p=0.025), relative to participants scoring 49/50. Though not statistically significant, results also showed a trend toward participants scoring 50/50 scoring higher on nearly every test in the battery. Conclusions: Participants with a single error on TOMM Trial 1, as compared to participants with a perfect score, performed significantly worse on a processing speed task, a verbal learning task, and a working memory task as part of a comprehensive neuropsychological battery. The single-error group also trended toward scoring lower on nearly all of the remaining attention, processing speed, perceptual ability, memory, and executive functioning tasks in the battery. The results could lead to a more liberal interpretation of TOMM scores, given that the trend towards lower performance may be due to putting forth significantly less effort. These results point to the need for a similar comparison of the TOMM in a larger sample size, as greater power may reveal even more significant differences in performance. Findings also emphasize the importance of viewing performance validity on a continuum rather than as a dichotomous pass/fail. Understanding the TOMM and how single errors may be indicative of poorer performance in a youth sample could help to reframe the way PVT results are interpreted in clinical and forensic settings. [ABSTRACT FROM AUTHOR]

Objective: Engagement in sporting activities has shown improvement in executive function among youth (Contreras-Osorio et al., 2021). Additionally, participation in specific sports such as soccer has been shown to enhance executive function in youth athletes compared to same-aged non-athletes (Yongtawee et al., 2021). The present study aimed to examine the effects of competitive participation in the United States' four most popular sports on executive function among youth athletes. The most popular sports, as defined by viewership, revenue, and youth participation in the U.S. are American football, basketball, baseball, and soccer (Injai, 2022; Aspen Institute, 2020). Participants and Methods: Data from the following three executive functioning subtests were analyzed in a sample of youth athletes (n=76), aged 8-18 years (mean age=11.94): Delis-Kaplan Executive Function System Trail Making Letter-Number Sequencing (cognitive flexibility), Wechsler Intelligence Scale for Children Fourth Edition Working Memory Index, and Golden Stroop Color-Word Inhibition. Participants completed these measures as part of a larger neuropsychological baseline assessment. Multivariate General Linear Model (GLM) regression was used to examine the influence of total cumulative years playing in one or more of the four most popular sports on executive functioning. A multivariate GLM regression also investigated the unique contributions of total years playing soccer (n=40; mean age=12.40) and total years playing American football (n=32; mean age=12.03) on subtest performance. The unique contributions of basketball (n=14) and baseball (n=21) were not analyzed due to small sample size. Results: Total cumulative years playing > one of the four most popular sports significantly predicted cognitive flexibility (p=.007) and working memory (p=.002), but not inhibition (p=0.639). Total years playing soccer also significantly predicted cognitive flexibility (p=.029) and working memory (p=0.05), but not inhibition (p=.310). Total years playing American football did not significantly predict performance on tasks requiring cognitive flexibility (p=.186), working memory (p=0.150), or inhibition (p=0.277). Conclusions: In congruence with previous research, sports participation predicted enhanced cognitive flexibility and working memory on certain executive tasks. Among youth athletes, prolonged competitive participation in one or more of the four most popular sports in the U.S. predicted better performance on measures of cognitive flexibility and working memory. Furthermore, protracted participation in soccer predicted enhanced performance on measures of cognitive flexibility and working memory, whereas extended participation in American football did not. Future research should examine this effect in larger samples within all four sports. Examining the cumulative length of competitive participation in these popular sports on executive function could present a favorable developmental outcome of youth participation if competitive participation is sustained. Additionally, the present data on executive function performance between lasting soccer participation and lasting American football participation suggests that executive function development and performance may be influenced by the sport played. The direction of this possible influence is unclear. More research is needed to establish this observed difference, and to better understand its existence and directionality. [ABSTRACT FROM AUTHOR]

Objective: Previous studies have evaluated the construct validity of the Serial Digit Learning Test (SDL) using principal component analysis (PCA; Larrabee et al., 1995; Greenman & Moses, 2016). In this study, we sought to re-investigate the SDL construct using a similar methodological approach with the Weschler Adult Intelligence Scale-4th ed. (WAIS-IV) and a performance validity measure. Method: Sample consisted of diagnostically diverse veterans referred for clinical neuropsychological assessment as part of their standard clinical care (N = 411). SDL-8-digit raw scores were submitted to PCA where a forced three factor solution was derived. Those derived factors were submitted to a second PCA using the four WAIS-IV index scores. Results: The SDL8 solution explained 83% of the variance, and factors reflected early, middle, and late trials. The second PCA produced an unforced four-factor solution explaining 71% of the variance. Excluding loading coefficients below +/−0.3, Component 1 showed loadings on WMI (0.805) and early trials (0.813), Component 2 showed loadings on PSI (0.800) and middle trials (0.789), Component 3 loaded on PRI (0.685) and late trials (0.829), and Component 4 loaded on VCI (0.951) and PSI (−0.348). Conclusions: These results replicated earlier research demonstrating that earlier SDL8 trials load on attentional/working memory measures and middle trials on processing speed. Unexpectedly, late trials loaded onto the Perceptual Reasoning Index, whereas they had previously loaded onto Verbal Comprehension of the WAIS-III. As these results may reflect the updated theoretical model underlying the WAIS-IV, further research replicating results which incorporated earlier WAIS-III perceptual reasoning (POI) measures is warranted. [ABSTRACT FROM AUTHOR]

• Confirming in-situ Structural Health Monitoring instruments are in working order. • Determine the in-situ properties of timber in real service conditions. • 3D, bimodular, orthotropic numerical model of a timber Warren truss structure. • Local in-situ load testing of a full-scale, heritage timber structure. • Identification of load and stress reversal within select timber members. This research paper presents the experimental results of an in-situ load-testing program within a WWII era, timber Warren truss structure located at Canadian Forces Base St-Jean, Quebec. Four point load tests were carried out on a 68 m long, Douglas fir timber truss instrumented with conventional electric strain gauges, distributed fibre optic sensors, and string potentiometers, among other instruments. These instruments makeup a larger, long-term structural health monitoring program implemented within the truss structure. The objectives of the local point load tests were to (1) confirm the in-situ monitoring instruments are in working order, (2) compare calculated mechanical properties with assumed properties, and (3) calibrate a numerical model capable of replicating truss response and compare to current modeling standards used within the Department of National Defence. Non-destructive testing, including moisture content and cable tension tests, was also conducted to determine existing material properties. Load testing and non-destructive testing results identified variations between the existing properties of the truss and the assumed properties of certain structural members, as well as identifying possible lower strength or stiffness values of stress-reversed members. Results also indicated the importance of analyzing timber as an orthotropic, bimodular material for reliability and conservatism, particularly in numerical modeling. Lastly, the results presented in this paper outline the importance of in-situ load testing with an aim to determine existing material properties for monitoring projects. Moreover, the identification of the existing properties and behaviour of the structure is fundamental in the development of a structural health monitoring program for emergency purposes. [ABSTRACT FROM AUTHOR]