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Data from neurocognitive assessments may not be accurate in the context of factors impacting validity, such as disengagement, unmotivated responding, or intentional underperformance. Performance validity tests (PVTs) were developed to address these phenomena and assess underperformance on neurocognitive tests. However, PVTs can be burdensome, rely on cutoff scores that reduce information, do not examine potential variations in task engagement across a battery, and are typically not well-suited to acquisition of large cognitive datasets. Here we describe the development of novel performance validity measures that could address some of these limitations by leveraging psychometric concepts using data embedded within the Penn Computerized Neurocognitive Battery (PennCNB).
We first developed these validity measures using simulations of invalid response patterns with parameters drawn from real data. Next, we examined their application in two large, independent samples: 1) children and adolescents from the Philadelphia Neurodevelopmental Cohort (n = 9498); and 2) adult servicemembers from the Marine Resiliency Study-II (n = 1444).
Our performance validity metrics detected patterns of invalid responding in simulated data, even at subtle levels. Furthermore, a combination of these metrics significantly predicted previously established validity rules for these tests in both developmental and adult datasets. Moreover, most clinical diagnostic groups did not show reduced validity estimates.
These results provide proof-of-concept evidence for multivariate, data-driven performance validity metrics. These metrics offer a novel method for determining the performance validity for individual neurocognitive tests that is scalable, applicable across different tests, less burdensome, and dimensional. However, more research is needed into their application.
Electronic platforms provide an opportunity to improve the informed consent (IC) process by permitting elements shown to increase research participant understanding and satisfaction, such as graphics, self-pacing, meaningful engagement, and access to additional information on demand. However, including these elements can pose operational and regulatory challenges for study teams and institutional review boards (IRBs) responsible for the ethical conduct and oversight of research. We examined the experience of two study teams at Alzheimer’s Disease Research Centers who chose to move from a paper-based IC process to an electronic informed consent (eIC) process to highlight some of these complexities and explore how IRBs and study teams can navigate them. Here, we identify the key regulations that should be considered when developing and using an eIC process as well as some of the operational considerations eIC presents related to IRB review and how they can be addressed.
This paper explores the potential of posthumanist feminism in archaeology. We find ourselves exhausted in the face of the continuing inequalities in our discipline and the volatile political times we live in, where discrimination and xenophobia, entangled with the patriarchy, create a toxic mix. In the face of this, we draw inspiration from ongoing activism within archaeology and the emergence of posthumanist feminism beyond archaeology. We consider the juxtaposition between activism in the discipline and the lack of engagement with the same issues in our theory. Posthumanist feminism is explored as a way to unite theory and activism. It connects to and builds on existing feminisms but is argued to differ in three ways: first, posthumanist feminism widens the scope of those for whom we should be working to achieve equality; second, it suggests radical shifts in our ontology are necessary to bring about equality; third, it develops an alternative approach to difference. We explore the potential for posthumanist feminism to reshape narratives about the past, the way we do archaeology, and archaeological activism. In each, the aim is to turn away from the majoritarian subject and to make space for multiple alternative voices to emerge and thrive in archaeology.
Evidence suggests a link between smaller hippocampal volume (HV) and post-traumatic stress disorder (PTSD). However, there has been little prospective research testing this question directly and it remains unclear whether smaller HV confers risk or is a consequence of traumatization and PTSD.
U.S. soldiers (N = 107) completed a battery of clinical assessments, including structural magnetic resonance imaging pre-deployment. Once deployed they completed monthly assessments of traumatic-stressors and symptoms. We hypothesized that smaller HV would potentiate the effects of traumatic stressors on PTSD symptoms in theater. Analyses evaluated whether total HV, lateral (right v. left) HV, or HV asymmetry (right – left) moderated the effects of stressor-exposure during deployment on PTSD symptoms.
Findings revealed no interaction between total HV and average monthly traumatic-stressors on PTSD symptoms b = −0.028, p = 0.681 [95% confidence interval (CI) −0.167 to 0.100]. However, in the context of greater exposure to average monthly traumatic stressors, greater right HV was associated with fewer PTSD symptoms b = −0.467, p = 0.023 (95% CI −0.786 to −0.013), whereas greater left HV was unexpectedly associated with greater PTSD symptoms b = 0.435, p = 0.024 (95% CI 0.028–0.715).
Our findings highlight the importance of considering the complex role of HV, in particular HV asymmetry, in predicting the emergence of PTSD symptoms in response to war-zone trauma.
Bipolar Disorder (BD) is associated with impairment in emotional self-regulation and verbal working memory. Lamotrigine (LTG) is effective in the clinical management of BD.
To investigate whether treatment with LTG is coupled with altered function within neural circuits subserving emotional processing and verbal working memory, in a BDI sample.
Functional Magnetic Resonance Imaging (MRI) was used to explore blood oxygenation level-dependent (BOLD) response across the whole brain in 12 stable BDI patients at baseline and following 12 weeks of LGT monotherapy. Stimuli were presented in a block-design while individuals performed a verbal working memory (N-back sequential letter) task and in an event-related fashion during an angry facial affect recognition task. Data was acquired using a 1.5-Tesla MRI scanner and analysed using SPM2. Group activation maps were generated for each task and for the drug-free and post-medication condition. A threshold of p < 0.001 was used. Effect of LGT on brain activation during tasks was explored using a random-effects, within-group comparison.
In both tasks, LGT monotherapy was associated with increased BOLD signal when compared to baseline in a number of brain regions, mostly within the prefrontal cortex and cingulate gyrus. All foci of increased activation with LTG monotherapy were observed within cortical regions normally engaged in verbal working memory and facial affect processing.
LTG monotherapy in BD patients may enhance cortical function within neural circuits involved in memory and emotional self-regulation.
This study was supported by an unrestricted GlaxoSmithKline grant.
We describe the design and deployment of GREENBURST, a commensal Fast Radio Burst (FRB) search system at the Green Bank Telescope. GREENBURST uses the dedicated L-band receiver tap to search over the 960–1 920 MHz frequency range for pulses with dispersion measures out to
. Due to its unique design, GREENBURST is capable of conducting searches for FRBs when the L-band receiver is not being used for scheduled observing. This makes it a sensitive single pixel detector capable of reaching deeper in the radio sky. While single pulses from Galactic pulsars and rotating radio transients will be detectable in our observations, and will form part of the database we archive, the primary goal is to detect and study FRBs. Based on recent determinations of the all-sky rate, we predict that the system will detect approximately one FRB for every 2–3 months of continuous operation. The high sensitivity of GREENBURST means that it will also be able to probe the slope of the FRB fluence distribution, which is currently uncertain in this observing band.
The methodical recording and representation of spatial data are central to archaeological fieldwork and research. Until recently, centimeter-level precise geolocation equipment was the exclusive domain of researchers who could afford setups costing tens of thousands of dollars. However, high-quality measurements are being made more accessible by rapidly evolving technologies. These new tools, when used together with mobile technology for efficiently recording field data, open up the possibility of capturing the precise location of every find during an archaeological surface survey. An important step in reaching the desired outcome—centimeter-level recording for all—is experimentation with a variety of emerging low-cost setups. Accordingly, we tested the Reach and Reach RS, differential global navigation satellite systems (dGNSS) equipment produced by the company Emlid, during a surface survey in Armenia in June 2018. Our field application demonstrates that the use of dGNSS is already possible and that the described advances in precision enable improved recording and representation of spatial data.
In this chapter, we discuss how new communication technologies are reshaping interpersonal relationship formation, maintenance, and dissolution. Through this evaluation, we extend existing research on the socio-technical affordances of computer-mediated communication (CMC) and relational processes by (1) synthesizing the current state of mediated personal relationships research across these three relational stages and (2) describing how each relational state is influenced by the affordances of new communication technologies. An affordances framework is especially useful for evaluating and understanding complex relationships and interactions on social media platforms because it captures the plastic nature of communication tools and the user practices that accompany them, providing a more holistic understanding of the interactions between users and the tools and how these relationships evolve over time. We argue that using an affordances framework to evaluate interpersonal relationship processes highlights how social and technological attributes shape interaction patterns while acknowledging individuals’ agency in deciding how they use communication tools. The chapter concludes with suggestions for future research in this area and describes some of the unique methodological, theoretical, and practical challenges of studying mediated interpersonal relationships.
Good education requires student experiences that deliver lessons about practice as well as theory and that encourage students to work for the public good—especially in the operation of democratic institutions (Dewey 1923; Dewy 1938). We report on an evaluation of the pedagogical value of a research project involving 23 colleges and universities across the country. Faculty trained and supervised students who observed polling places in the 2016 General Election. Our findings indicate that this was a valuable learning experience in both the short and long terms. Students found their experiences to be valuable and reported learning generally and specifically related to course material. Postelection, they also felt more knowledgeable about election science topics, voting behavior, and research methods. Students reported interest in participating in similar research in the future, would recommend other students to do so, and expressed interest in more learning and research about the topics central to their experience. Our results suggest that participants appreciated the importance of elections and their study. Collectively, the participating students are engaged and efficacious—essential qualities of citizens in a democracy.
Traumatic stressors during childhood and adolescence are associated with psychopathology, mostly studied in the context of post-traumatic stress disorder (PTSD) and depression. We investigated broader associations of traumatic stress exposure with psychopathology and cognition in a youth community sample.
The Philadelphia Neurodevelopmental Cohort (N = 9498) is an investigation of clinical and neurobehavioral phenotypes in a diverse (56% Caucasian, 33% African American, 11% other) US youth community population (aged 8–21). Participants were ascertained through children's hospital pediatric (not psychiatric) healthcare network in 2009–2011. Structured psychiatric evaluation included screening for lifetime exposure to traumatic stressors, and a neurocognitive battery was administered.
Exposure rate to traumatic stressful events was high (none, N = 5204; one, N = 2182; two, N = 1092; three or more, N = 830). Higher stress load was associated with increased psychopathology across all clinical domains evaluated: mood/anxiety (standardized β = .378); psychosis spectrum (β = .360); externalizing behaviors (β = .311); and fear (β = .256) (controlling for covariates, all p < 0.001). Associations remained significant controlling for lifetime PTSD and depression. Exposure to high-stress load was robustly associated with suicidal ideation and cannabis use (odds ratio compared with non-exposed 5.3 and 3.2, respectively, both p < 0.001). Among youths who experienced traumatic stress (N = 4104), history of assaultive trauma was associated with greater psychopathology and, in males, vulnerability to psychosis and externalizing symptoms. Stress load was negatively associated with performance on executive functioning, complex reasoning, and social cognition.
Traumatic stress exposure in community non-psychiatric help-seeking youth is substantial, and is associated with more severe psychopathology and neurocognitive deficits across domains, beyond PTSD and depression.
Here, we present initial results from the ALFABURST radio transient survey, which is currently running in a commensal mode with the ALFA receiver at the Arecibo telescope. We observed for a total of 1400 hours and have detected single pulses from known pulsars but did not detect any FRBs. The non-detection of FRBs is consistent with the current FRB sky rates.
Herbicide resistance is the heritable ability of a weed biotype or population to survive a herbicide application that would effectively kill a susceptible population of the weed. In the U.K. the most widespread and financially important herbicide-resistant weed is blackgrass. Investigations to elucidate the molecular mechanisms conferring herbicide resistance to blackgrass populations have been ongoing for two decades. Although the identification of target site–resistant populations has proved to be relatively straightforward (using, for example, target site assays in vitro), the study and understanding of resistance mechanisms involved in enhanced metabolism has proven to be more problematic. Research has focused on the cytochrome P450 monooxygenase and glutathione S-transferase (GST) enzyme families, both of which have been shown to be important in herbicide metabolism in many weed and crop species. GST activity and abundance are greater in a selection of herbicide-resistant blackgrass biotypes, and herbicide treatment of field populations of blackgrass results in the survival of the proportion of population possessing the greatest GST activity and abundance. In addition, GST activity in the field increases between winter and spring, and this coincides with reduced efficacy of important blackgrass herbicides. GST activities within field populations of blackgrass are highly varied, and this plasticity is discussed in relation to the development of resistant populations in field situations. This article describes research results in blackgrass and compares them with GST studies in other weed species as well as with other mechanisms for enhanced metabolism-based resistance.
Objectives: Neuropsychological studies of posttraumatic stress disorder (PTSD) have revealed deficits in attention/working memory, processing speed, executive functioning, and retrospective memory. However, little is known about prospective memory (PM) in PTSD, a clinically relevant aspect of episodic memory that supports the encoding and retrieval of intentions for future actions. Methods: Here we examined PM performance in 40 veterans with PTSD compared to 38 trauma comparison (TC) veterans who were exposed to combat but did not develop PTSD. All participants were administered the Memory for Intentions Test (MIST; Raskin, Buckheit, & Sherrod, 2010), a standardized and validated measure of PM, alongside a comprehensive neurocognitive battery, structured diagnostic interviews for psychiatric conditions, and behavioral questionnaires. Results: Veterans with PTSD performed moderately lower than TC on time-based PM, with errors primarily characterized as PM failure errors (i.e., omissions). However, groups did not differ in event-based PM, ongoing task performance, or post-test recognition of PM intentions for each trial. Lower time-based PM performance was specifically related to hyperarousal symptoms of PTSD. Time-based-performance was also associated with neuropsychological measures of retrospective memory and executive functions in the PTSD group. Nevertheless, PTSD was significantly associated with poorer PM above and beyond age and performance in retrospective memory and executive functions. Discussion: Results provide initial evidence of PM dysfunction in PTSD, especially in strategic monitoring during time-based PM tasks. Findings have potential implications for everyday functioning and health behaviors in persons with PTSD, and deserve replication and future study. (JINS, 2016, 22, 724–734)
Objectives: Numerous studies have shown that individuals with posttraumatic stress disorder (PTSD) display reduced performances on neuropsychological tests, although most prior research has not adequately accounted for comorbidities or performance validity concerns that are common in this population and could partially account for the observed neurocognitive findings. Moreover, few studies have examined the functional implications of neuropsychological results in PTSD. Methods: We examined neuropsychological functioning in 44 veterans with PTSD and 40 veteran trauma comparison (TC) participants with combat exposure and no PTSD. Results: After excluding four veterans with PTSD for performance validity concerns, multivariate analyses of variance by neurocognitive domain revealed significantly worse performance by the PTSD group in the domains of speed of information processing (p=.035) and executive functions (p=.017), but no group differences in attention/working memory, verbal/language functioning, visuoconstruction, or episodic memory. Group differences by PTSD status were still present after covarying for depression, a history of head injuries, and substance use disorders. Executive functioning performance was associated with poorer self-reported occupational functioning and physical health-related quality of life, while speed of information processing performance was associated with poorer physical health-related quality of life. Discussion: These results are generally consistent with a fronto-limbic conceptualization of PTSD-associated neuropsychological dysfunction and show that cognitive functioning may be associated with critical functional outcomes. Taken together, results suggest that consideration of neurocognitive functioning may enhance the clinical management of individuals with PTSD. (JINS, 2016, 22, 399–411)
Ultrasonic nondestructive evaluation methods are routinely used to detect and size fatigue cracks near fastener holes in aircraft structures as a part of scheduled maintenance. In contrast, statistical crack propagation models provide an estimate of the expected fatigue life assuming a known crack size and future fatigue loadings. Here an integrated approach for in situ diagnosis and prognosis of fastener hole fatigue cracks is proposed and implemented that incorporates both ultrasonic monitoring and crack growth laws. The sensing method is an ultrasonic angle beam technique, and cracks are automatically detected from the ultrasonic response. An extended Kalman filter is applied to combine ultrasonically estimated crack sizes with a crack growth law, effectively using the time history of the ultrasonic results rather than only the most recent measurement. A natural extension of this method is fatigue life prognosis. Results from fatigue tests on 7075-T651 aluminium coupons show improved crack size estimates as compared to those obtained from ultrasonic measurements alone, and also demonstrate the capability of predicting the remaining life. This approach for fatigue crack detection, sizing and prognosis is an example of a general strategy for in situ monitoring of structural damage whereby improved results are achieved from the integration of noisy measurements with imperfect crack growth models.
Influenza A (H1N1) pdm09 became the predominant circulating strain in the United States during the 2013–2014 influenza season. Little is known about the epidemiology of severe influenza during this season.
A retrospective cohort study of severely ill patients with influenza infection in intensive care units in 33 US hospitals from September 1, 2013, through April 1, 2014, was conducted to determine risk factors for mortality present on intensive care unit admission and to describe patient characteristics, spectrum of disease, management, and outcomes.
A total of 444 adults and 63 children were admitted to an intensive care unit in a study hospital; 93 adults (20.9%) and 4 children (6.3%) died. By logistic regression analysis, the following factors were significantly associated with mortality among adult patients: older age (>65 years, odds ratio, 3.1 [95% CI, 1.4–6.9], P=.006 and 50–64 years, 2.5 [1.3–4.9], P=.007; reference age 18–49 years), male sex (1.9 [1.1–3.3], P=.031), history of malignant tumor with chemotherapy administered within the prior 6 months (12.1 [3.9–37.0], P<.001), and a higher Sequential Organ Failure Assessment score (for each increase by 1 in score, 1.3 [1.2–1.4], P<.001).
Risk factors for death among US patients with severe influenza during the 2013–2014 season, when influenza A (H1N1) pdm09 was the predominant circulating strain type, shifted in the first postpandemic season in which it predominated toward those of a more typical epidemic influenza season.
Infect. Control Hosp. Epidemiol. 2015;36(11):1251–1260
The present study compared executive dysfunction among children with attention-deficit/hyperactivity disorder (ADHD) after traumatic brain injury (TBI), also called secondary ADHD (S-ADHD), pre-injury ADHD and children with TBI only (i.e., no ADHD). Youth aged 6–16 years admitted for TBI to five trauma centers were enrolled (n=177) and evaluated with a semi-structured psychiatric interview scheduled on three occasions (within 2 weeks of TBI, i.e., baseline assessment for pre-injury status; 6-months and 12-months post-TBI). This permitted the determination of 6- and 12-month post-injury classifications of membership in three mutually exclusive groups (S-ADHD; pre-injury ADHD; TBI-only). Several executive control measures were administered. Unremitted S-ADHD was present in 17/141 (12%) children at the 6-month assessment, and in 14/125 (11%) children at 12-months post-injury. The study found that children with S-ADHD exhibited deficient working memory, attention, and psychomotor speed as compared to children with pre-injury ADHD. Furthermore, the children with S-ADHD and the children with TBI-only were impaired compared to the children with pre-injury ADHD with regard to planning. No group differences related to response inhibition emerged. Age, but not injury severity, gender, or adaptive functioning was related to executive function outcome. Neuropsychological sequelae distinguish among children who develop S-ADHD following TBI and those with TBI only. Moreover, there appears to be a different pattern of executive control performance in those who develop S-ADHD than in children with pre-injury ADHD suggesting that differences exist in the underlying neural mechanisms that define each disorder, underscoring the need to identify targeted treatment interventions. (JINS, 2014, 20, 971–981)
Although beta-amyloid, anxiety and depression have been linked cross-sectionally to reduced memory function in healthy older adults without dementia, prospective data evaluating these associations are lacking. Using data from an observational cohort study of 178 healthy older adults without dementia followed for 3 years, we found that anxiety symptoms significantly moderated the relationship between beta-amyloid level and decline in verbal (Cohen's d = 0.65) and episodic (Cohen's d = 0.38) memory. Anxiety symptoms were additionally linked to greater decline in executive function, irrespective of beta-amyloid and other risk factors. These findings suggest that interventions to mitigate anxiety symptoms may help delay memory decline in otherwise healthy older adults with elevated beta-amyloid.