Papers by Stephen Lieberman
Developmental neuropsychology, 2018
Using multiple mediation with bootstrapping, dimensions of executive functioning (i.e., inhibitor... more Using multiple mediation with bootstrapping, dimensions of executive functioning (i.e., inhibitory control, working memory, set shifting) were tested as mediators of predictions of academic and social outcomes from observed positive and negative parenting in 131 children followed prospectively into early adolescence. Inhibitory control and working memory mediated predictions of academic achievement, whereas inhibitory control meditated predictions of school competence from positive parenting. Additionally, working memory mediated predictions of negative social preference, but not social competence, from positive parenting. Executive functioning did not mediate predictions from negative parenting. The role of parenting in shaping youth outcomes through executive functioning is considered.
Molecular cancer therapeutics, Jan 15, 2018
Macromolecular cancer drugs such as therapeutic antibodies and nanoparticles are well known to di... more Macromolecular cancer drugs such as therapeutic antibodies and nanoparticles are well known to display slow extravasation and incomplete penetration into tumors, potentially protecting cancer cells from therapeutic effects. Conventional assays to track macromolecular drug delivery are poorly matched to the heterogeneous tumor microenvironment, but recent progress on optical tissue clearing and three-dimensional (3D) tumor imaging offers a path to quantitative assays with cellular resolution. Here, we apply Transparent Tissue Tomography (T3) as a tool to track perfusion and delivery in the tumor and to evaluate target binding and vascular permeability. Using T3, we mapped anti-programmed cell death protein-ligand 1 (PD-L1) antibody distribution in whole mouse tumors. By measuring 3D penetration distances of the antibody drug out from the blood vessel boundaries into the tumor parenchyma, we determined spatial pharmacokinetics of anti-PD-L1 antibody drugs in mouse tumors. With multipl...
Journal of patient-reported outcomes, 2017
Parents' perceptions of their 8-17-year-old children's oral health status were assessed u... more Parents' perceptions of their 8-17-year-old children's oral health status were assessed using a sample from diverse dental clinics in Greater Los Angeles County to identify constructs for a survey instrument. Focus groups with 29 parents or guardians were conducted to identify themes that informed development of survey items. The draft items were administered to a different group of 32 parents or guardians in cognitive interviews, and revised for subsequent field-testing. Thematic and narrative analyses were performed after the focus groups and key lay-oriented dimensions were uncovered, notably the relationship between oral health, systemic health and the life course. In the cognitive interviews, parents entered multiple responses to questions related to the look of their child's teeth, and their overall perception of tooth color. Parents also assessed their child's fear or discomfort with the dental experience, and other social and psychological concerns related to...
Quality of life research : an international journal of quality of life aspects of treatment, care and rehabilitation, Jan 5, 2018
Children and adolescents are vulnerable to dental problems and oral diseases. This paper presents... more Children and adolescents are vulnerable to dental problems and oral diseases. This paper presents the development of two multi-item self-report scales for use in assessing oral health status of children and adolescents. Following the Patient-Reported Outcome Measurement Information System framework, survey questions were designed using a newly developed conceptual model. These items were administered to 334 children and adolescents (8-17 years) along with concurrent dental exams. Exploratory and confirmatory factor analyses were conducted and the item response theory graded response model was used to estimate item parameters and oral health status scores and to identify short-form items. The items were selected by high level of information and wide coverage of different domains to assess Child Oral Health Status Index (COHSI) and treatment referral recommendations (RR). The long form consists of 28 items. The short-form includes 12 items (8 for COHSI and 7 for RR with 3 common items...
Arthritis & rheumatology (Hoboken, N.J.), Aug 16, 2017
This collaboration between the American College of Rheumatology and the American Association of H... more This collaboration between the American College of Rheumatology and the American Association of Hip and Knee Surgeons developed an evidence-based guideline for the perioperative management of antirheumatic drug therapy for adults with rheumatoid arthritis (RA), spondyloarthritis (SpA) including ankylosing spondylitis and psoriatic arthritis, juvenile idiopathic arthritis (JIA), or systemic lupus erythematosus (SLE) undergoing elective total hip (THA) or total knee arthroplasty (TKA). A panel of rheumatologists, orthopedic surgeons specializing in hip and knee arthroplasty, and methodologists was convened to construct the key clinical questions to be answered in the guideline. A multi-step systematic literature review was then conducted, from which evidence was synthesized for continuing versus withholding antirheumatic drug therapy and for optimal glucocorticoid management in the perioperative period. A Patient Panel was convened to determine patient values and preferences, and the ...
Journal of clinical child and adolescent psychology : the official journal for the Society of Clinical Child and Adolescent Psychology, American Psychological Association, Division 53, Jan 18, 2016
Although birth weight is a potential causal risk factor for attention-deficit/hyperactivity disor... more Although birth weight is a potential causal risk factor for attention-deficit/hyperactivity disorder (ADHD) symptoms, both the specificity of this association and its mediating pathways are largely unknown. We carefully assessed youth with and without ADHD (i.e., Wave 1), and followed them prospectively for 2 years (i.e., Wave 2). We (a) tested the association of birth weight with Wave 2 ADHD symptoms, and (b) evaluated biologically plausible neurocognitive functions from Wave 1 as temporally ordered mediators of birth weight and Wave 2 ADHD symptoms in a multiple mediation framework. At Wave 1, 222 ethnically diverse youth (30% female; ages 5-10) completed the Digit Span, Vocabulary, Symbol Search, and Arithmetic subtests of the Wechsler Intelligence Scale for Children-IV. At both Wave 1 and Wave 2 (ages 7-13), multiple informants (i.e., parents, teachers) rated youth ADHD symptoms and co-occurring psychopathology using multiple methods (i.e., structured interview, rating scale). C...
Journal of clinical child and adolescent psychology : the official journal for the Society of Clinical Child and Adolescent Psychology, American Psychological Association, Division 53, Jan 18, 2016
The serotonin transporter-linked polymorphic region (5-HTTLPR) is associated with caregiving in n... more The serotonin transporter-linked polymorphic region (5-HTTLPR) is associated with caregiving in nonhuman animals and with affective and cognitive correlates of human parenting, yet its association with human parenting is largely unknown. Using a well-characterized sample of parents and offspring, we evaluated the association of parental 5-HTTLPR with observed positive and negative parenting behavior, as well as its biologically plausible moderation of child-related stress and disruptive child behavior as predictors of parenting. One hundred and sixty-two parents (86% mothers) and their 6- to 9-year-old children with and without attention-deficit/hyperactivity disorder were ascertained using multiple methods including structured interviews, rating scales, and observed parent-child interaction, yielding strong measures of key constructs. Controlling for multiple youth-level (e.g., sex, 5-HTTLPR genotype, disruptive behavior) and parent-level (e.g., demographics, depression, attention-...
Motivation: Increased throughput and diverse experimental designs of large-scale sequencing studi... more Motivation: Increased throughput and diverse experimental designs of large-scale sequencing studies necessi-tate versatile, scalable and robust variant calling tools. In particular, identification of copy number changes re-mains a challenging task due to their complexity, susceptibility to sequencing biases, variation in coverage data and dependence on genome-wide sample properties, such as tumor polyploidy or polyclonality in cancer samples. Results: We have developed a new tool, Canvas, for identification of copy number changes from diverse se-quencing experiments including whole-genome matched tumor-normal and single-sample normal re-sequencing, as well as whole-exome matched and unmatched tumor-normal studies. In addition to variant calling, Canvas infers genome-wide parameters such as cancer ploidy, purity and heterogeneity. It provides fast and simple to execute workflows that can scale to thousands of samples and can be easily incorporated into existing variant calling pipeli...
Journal of abnormal child psychology, Jul 21, 2015
Attention-deficit/hyperactivity disorder (ADHD) reliably predicts social dysfunction, ranging fro... more Attention-deficit/hyperactivity disorder (ADHD) reliably predicts social dysfunction, ranging from poor social competence and elevated peer rejection to inadequate social skills. Yet, the factors mediating predictions of social problems from childhood ADHD are not well understood. In the present study, we investigated social functioning in 186 (69 % male) 6 to 10 year-old (M = 7.88, SD = 1.17) children with (n = 98) and without (n = 87) ADHD who were followed prospectively for two years. We implemented a well-validated measure of social problems as well as a novel social decision-making task assessing dynamic response to changing affective cues at the two-year follow-up. According to separate parent and teacher report, baseline ADHD symptoms positively predicted social problems at the two-year follow-up; individual differences on the social decision-making task mediated this association. This finding was replicated when ADHD dimensions (i.e., inattention and hyperactivity/impulsivit...
HAND, 2015
Purpose This study described physical and psychosocial limitations associated with adult brachial... more Purpose This study described physical and psychosocial limitations associated with adult brachial plexus injuries (BPI) and patients' expectations of BPI surgery. Methods During in-person interviews, preoperative patients were asked about expectations of surgery and preoperative and postoperative patients were asked about limitations due to BPI. Postoperative patients also rated improvement in condition after surgery. Data were analyzed with qualitative and quantitative techniques. Results Ten preoperative and 13 postoperative patients were interviewed; mean age was 37 years, 19 were men, all were employed/students, and most injuries were due to trauma. Preoperative patients cited several main expectations, including pain-related issues, and improvement in arm movement, self-care, family interactions, and global life function. Workrelated expectations were tailored to employment type. Preoperative and postoperative patients reported that pain, altered sensation, difficulty manag...
SPIE Proceedings, 2012
The High Efficiency and Resolution Multi Element Spectrograph, HERMES is an optical spectrograph ... more The High Efficiency and Resolution Multi Element Spectrograph, HERMES is an optical spectrograph designed primarily for the GALAH, Galactic Archeology Survey, the first major attempt to create a detailed understanding of galaxy formation and evolution by studying the history of our own galaxy, the Milky Way 1 . The goal of the GALAH survey is to reconstruct the mass assembly history of the of the Milky way, through a detailed spatially tagged abundance study of one million stars in the Milky Way. The spectrograph will be based at the Anglo Australian Telescope (AAT) and be fed with the existing 2dF robotic fibre positioning system. The spectrograph uses VPH-gratings to achieve a spectral resolving power of 28,000 in standard mode and also provides a high resolution mode ranging between 40,000 to 50,000 using a slit mask. The GALAH survey requires a SNR greater than 100 aiming for a star brightness of V=14. The total spectral coverage of the four channels is about 100nm between 370 and 1000nm for up to 392 simultaneous targets within the 2 degree field of view. Current efforts are focused on manufacturing and integration. The delivery date of spectrograph at the telescope is scheduled for 2013. A performance prediction is presented and a complete overview of the status of the HERMES spectrograph is given. This paper details the following specific topics: The approach to AIT, the manufacturing and integration of the large mechanical frame, the opto-mechanical slit assembly, collimator optics and cameras, VPH gratings, cryostats, fibre cable assembly, instrument control hardware and software, data reduction.
Journal of Attention Disorders, 2012
Objective: To investigate whether individual differences in coping self-efficacy mediated the ass... more Objective: To investigate whether individual differences in coping self-efficacy mediated the association of child abuse and symptoms of ADHD in young adults. Method: Self-reported measures of coping self-efficacy, child abuse, and ADHD were obtained from 66 adults. Results: Adults who reported childhood physical or sexual abuse (prior to the age of 17) had significantly higher levels of ADHD than those who did not. Individual differences in coping self-efficacy fully mediated the association between child abuse and ADHD symptoms in adulthood, such that individuals who endorsed child abuse had lower coping self-efficacy, and coping self-efficacy negatively predicted ADHD symptoms. Discussion: The findings suggest a potential causal mechanism by which childhood physical and sexual abuse may result in ADHD symptoms later in life. Interventions that improve coping skills may be useful in preventing later ADHD symptoms among adults with a childhood history of physical and sexual abuse.
The Cultural Geography Model: An Agent Based Modeling Framework for Analysis of the Impact of Culture in Irregular Warfare
The development of tools to provide insight into the behavioral response of a civilian population... more The development of tools to provide insight into the behavioral response of a civilian population will greatly benefit the modeling and simulation community and have potential applications across multiple user communities in the U.S. Department of Defense. We present an overview of a modular agent-based modeling framework, grounded in the human behavioral and social theory, which is intended to represent a populations’ stance on issues as a function of their changing beliefs, values and interests. We utilize and integrate theories of narrative identity [1] and planned behavior [2] with macrosociological theories of heterogeneity and influence [3][4] to model civilian behavior in a conflict ecosystem. Communication between agents takes place across a social network developed using real data about the population under consideration, and essential services are implemented as objects within the model allowing for experimentation with different courses of action for development of civil service capacity. We describe the theoretical underpinnings of the model, the current state of implementation, potential use cases, and the path forward for future work.
A use-case approach to the validation of social modeling and simulation
ABSTRACT The modeling and simulation (M&S) community is faced with the task of informing ... more ABSTRACT The modeling and simulation (M&S) community is faced with the task of informing public policy decision makers, from both the defense community and from the civilian sector, of the impact of their decisions on the beliefs, values and interests (BVIs) of the populations in their areas of influence. The M&S techniques used for these types of analyses by necessity challenge the traditional boundaries and methods regarding validation efforts. Given that the analysis of populations is largely intractable via reductionist methodologies, we posit that insight must be garnered through experiment and iteration using simulated societies. Further, the designs of these simulation experiments must be based on the information needs of the community. We discuss the concept of developing social simulations by use case, the validation of data sources for model development, validation techniques guided by usefulness, and a case study approach to validation of social simulations.
Modeling the Theory of Planned Behavior from Survey Data for Action Choice in Social Simulations
ABSTRACT Current dialogues across a variety of disciplines from the social, behavioral and comput... more ABSTRACT Current dialogues across a variety of disciplines from the social, behavioral and computer sciences have made clear the need for authentic, repeatable and actionable social simulations. Understanding how the individuals that comprise various populations (and segments of society) might respond to a given set of conditions provides the potential to better inform analysts and decision makers in a wide variety of settings. Here we examine the implications of applying a well-documented behavioral prediction theory, Icek Ajzen's Theory of Planned Behavior (TPB), within a social simulation in the context of public policy decision making. We provide brief overviews of both TPB and the construction of artificial societies, a full description of the TPB implementation within an artificial society, and develop an argument for the benefits of informing action choice models such as TPB from representative survey data.
National Conference on Artificial Intelligence, 2010
Representing human behavior and cognition, from individuals to societies, presents a range of cha... more Representing human behavior and cognition, from individuals to societies, presents a range of challenges to the modeling and simulation community. A common thread through many of these challenges is formulating an authentic representation of time. Many of the issues related to time representation, from the sequencing of cognitive decision processes and information processing, to communication and interaction between agents, to the longer term time scales associated with ideas such as belief revision, remain open research areas throughout the community. The inherent variability between human subjects makes generalization difficult even with data from designed experiments. Discrete event simulation (DES) provides a well-documented alternative to time-step simulation and shows potential for applications across the domain of human behavior representation. This paper provides an overview of a modular discrete event framework for social simulation, along with the social and behavioral theories underlying the currently implemented modules. We discuss the practical challenges presented by time in the representation of human cognition, and provide a case study analysis of the output of the discrete event social simulation.
Visualizing the human, social, cultural and behavioral components of a complex conflict ecosystem
ABSTRACT Creating meaningful visualizations of multi-dimensional human, social, cultural, and beh... more ABSTRACT Creating meaningful visualizations of multi-dimensional human, social, cultural, and behavioral (HSCB) data will provide greater insights to operational decision makers across a large variety of problem domains. Developing and deploying visualization tools presents a variety of challenges to the analytic community, and these are further compounded when presenting information on the non-traditional dimensions of the battlefield encompassed by HSCB domain. Given that the center of gravity in Irregular Warfare is the population, the need for battlefield commanders to understand this information in operationally relevant ways is clear. Here we provide an overview of the challenges in providing visual displays of HSCB data for decision support, and the methods chosen for communicating the output of a social simulation. We use the Cultural Geography model as an example of a social simulation with accompanying visualizations, discuss the importance of display configurations, and propose several paths forward for future work in HSCB data visualization.
The Cultural Geography Model: Evaluating the Impact of Tactical Operational Outcomes on a Civilian Population in an Irregular Warfare Environment
The Journal of Defense Modeling and Simulation, Oct 1, 2009
The civilian population has been described as ‘the center of gravity in irregular warfare’. Under... more The civilian population has been described as ‘the center of gravity in irregular warfare’. Understanding the behavioral response of the civilian population in irregular warfare operations presents a major challenge area to the joint modeling and simulation community where there is a clear need for the development of models, methods, and tools to address civilian behavior response. This paper provides a conceptual and theoretical overview of the Cultural Geography (CG) model, a government-owned, open-source agent-based model designed to address the behavioral response of civilian populations in conflict environments. With an embedded case study, we describe the development of cognitive modules to represent the civilian population and their implementation as Bayesian belief networks (BBNs), the social structure module implemented using homophily, the process of adjudicating the effects of tactical level outcomes on a population segment within the model, and a sample case study analysis using a designed experiment.
Developing Social Networks for Artificial Societies from Survey Data
Lecture Notes in Computer Science, 2010
ABSTRACT Authentically representing large social collectivities remains a preeminent challenge th... more ABSTRACT Authentically representing large social collectivities remains a preeminent challenge throughout the social computing, and modeling and simulation communities. We demonstrate here a simple technique that uses survey and polling data to embed agents with attributes and endogenously elicit an authentic and theory-driven simulation social structure for an artificial society. We furthermore show that a representation of social structure based on internal agent attributes allows for the continuous representation of social dynamics that affect agent cognition and association, and that social structures for artificial societies can be generated without any loss to the granularity of the underlying data or simulation output. We provide a case study using social survey data to demonstrate the method and effects, document the visualization of social structure for the population of Indonesia, discuss the implications and uses of survey data for social simulation, and suggest several paths forward for social and behavioral predictive modeling.
Winter Simulation Conference, Dec 11, 2011
We investigate the effects of time advance mechanisms on the behavior of agents in combat simulat... more We investigate the effects of time advance mechanisms on the behavior of agents in combat simulations using some simple scenarios relevant to combat and agent-based models. We implement these simulation designs in two modeling packages that illustrate the differences between discrete-time simulation (DTS) and discrete-event simulation (DES) methodologies. Many combat models use DTS as their simulation time advance mechanism. We demonstrate that the presence and size of the time step as a modeling component can have a substantial impact on the basic characteristics of agent and simulation performance. We show that the use of a DTS method can degrade the modeling accuracy of changes in agent sensor range and detection outcomes, and also can compromise the ability of agents to travel to specific target destinations in a spatial simulation environment. We conclude that DES methodology successfully addresses these problems and is preferred as a time advance mechanism in these situations.
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Papers by Stephen Lieberman