Trajectories Of Aggression Research Articles

Nonlinear Model Predictive Control for Unmanned Aerial Vehicles

This paper discusses the derivation and implementation of a nonlinear model predictive control law for tracking reference trajectories and constrained control of a quadrotor platform. The approach uses the state-dependent coefficient form to capture the system nonlinearities into a pseudo-linear system matrix. The state-dependent coefficient form is derived following a rigorous analysis of aerial vehicle dynamics that systematically accounts for the peculiarities of such systems. The same state-dependent coefficient form is exploited for obtaining a nonlinear equivalent of the model predictive control. The nonlinear model predictive control law is derived by first transforming the continuous system into a sampled-data form and and then using a sequential quadratic programming solver while accounting for input, output and state constraints. The boundedness of the tracking errors using the sampled-data implementation is shown explicitly. The performance of the nonlinear controller is illustrated through representative simulations showing the tracking of several aggressive reference trajectories with and without disturbances.

The Influence of Preschoolers' Aggression Trajectory on Relationships with Parents, Teachers and Peers

The Influence of Preschoolers' Aggression Trajectory on Relationships with Parents, Teachers and Peers

We are losing the climate change mitigation challenge; Is it too late to recover?

ABSTRACT

Decentralized polynomial trajectory generation for flight formation of quadrotors

This paper deals with the decentralized polynomial trajectory generation for the formation flight of a leader–follower network of quadrotors. The proposed decentralized trajectory planning method guarantees stability of the formation in missions with aggressive trajectories or low information exchange frequencies or data loss. Moreover, designed formation protocol ensures robustness of the formation against variations of the network communication topology. First, quadrotor translational dynamics is represented as a quadruple integrator by linearizing and differentiating its equations of translational motion. Then, a formation control law for a leader–follower network of the quadruple integrators is designed by implementing robustness properties of linear quadratic regulator design method and special characteristics of the network graph. Moreover, sufficient condition for the robustness of the formation against possible variations of the communication topology is addressed. According to the represented trajectory generation algorithm, once a follower receives information from its neighbors (e.g. coefficients of their intended polynomial trajectories), it plans a polynomial trajectory. To generate proper trajectories, integral of squared magnitude of error between the snap of the trajectory and its determined value by the formation control law over a finite horizon time should be minimized. The optimization problem can be formulated as a quadratic problem, which can be solved in real time. Furthermore, actuators limits can be imposed on the optimization problem as inequality constraints. As it is validated in the simulations, this predictive model of the trajectory generation provides stability of the formation in operations with aggressive trajectories or low information update frequencies or probability of data packets loss. Additionally, the quadrotors track the planned trajectories via implementing a hierarchical nonlinear trajectory tracking controller including a position controller and a geometrical attitude controller. Stability of the tracking error dynamics is proven by Lyapunov stability theorem. Expected capabilities of the formation control law, trajectory generation method and nonlinear trajectory tracking controller are examined in numerical simulations. In all of the simulations, an experimentally verified full model of a specific quadrotor taken from literatures is used.

Reciprocal Relations between the Trajectories of Mothers' Harsh Discipline, Responsiveness and Aggression in Early Childhood.

Theoretical advances in the study of the development of aggressive behaviors indicate that parenting behaviors and child aggression mutually influence one another. This study contributes to the body of empirical research in this area by examining the development of child aggression, maternal responsiveness, and maternal harsh discipline, using 5-year longitudinal data from a nationally representative sample of Turkish children (n=1009; 469 girls and 582 boys). Results indicated that: (i) maternal responsiveness and harsh discipline at age 3 were associated with the subsequent linear trajectory of aggression; (ii) reciprocally, aggressive behaviors at age 3 were associated with the subsequent linear trajectories of these two types of parenting behaviors; (iii) deviations from the linear trajectories of the child and mother behaviors tended to be short lived; and, (iv) the deviations of child behaviors from the linear trajectories were associated with the subsequent changes in mother behaviors after age 5. These findings are discussed in the cultural context of this study.

Change trajectories of aggressive behavior among children in long-term residential care

This study examined change trajectories of aggressive behaviors among children in long-term residential care in Israel and identified various child-, family-, and placement-related predictors of the change trajectories. Records of 799 children (average age at the beginning of the four years=10.4, 33.1% female) in their first four consecutive years in care were analyzed using the TRF aggressive behavior subscale (Achenbach, 1991) to measure the outcome variable. Children’s and parents’ characteristics and placement-related factors were used to explain variance in change trajectories. Latent Class Growth Analyses identified four aggressive behavior trajectories: ‘stable-low’ levels of aggressiveness over time (45% of the children), ‘stable-high’ levels (13%), ‘improvement’ (20%), and ‘deterioration’ (22%). Predictors of less resilient trajectories (i.e., stable-high or increasing aggressiveness) included mothers’ difficulties and disabilities, children’s attendance of special education classes, more intensive type of care, and non-immigrant status. The Attachment Theory, Life Course Perspective theories, and the General Strain Theory are used to interpret some of the findings of the study. Identifying the factors that predispose children to certain patterns of change may help direct resources to children at risk of having high or increasing levels of aggression while in residential care.

DEVELOPMENT AND SOCIALIZATION OF PHYSICAL AGGRESSION IN VERY YOUNG BOYS

The expression of physical aggression is normative in early child development; it peaks in the second year of life, with steep declines for most children by the third and fourth years as children learn alternatives to aggression. Some children, however, fail to demonstrate declines in aggressive acts, and many of these are boys. The current review uses a dynamic systems (DS) approach to identify early individual and contextual factors that may dynamically influence trajectories of aggression as a characteristic way of engaging within communities and relationships. Within the DS framework, we focus on the parent-infant relationship as central to the development of adaptive emotion-regulation capacities of the infant and young child. Biological sex differences that may influence this early relationship are highlighted, as is the influence of contextual processes such as family violence. Clinical implications suggested by both the empirical and theoretical literatures are then described.

Growth mixture modeling of post-combat aggression: Application to soldiers deployed to Iraq.

Prior research has found substantial heterogeneity in the course of key post-deployment outcomes, such as PTSD. The current paper employs growth mixture modeling to identify differential trajectories of change in the course of post-combat aggression. A Brigade Combat Team completed surveys within 72h of return from an Iraq deployment, 4 months later, and at 12 months after return. Based on model fit indices, analyses yielded four latent aggression trajectories: "low-stable", "delayed", "recovery", and "chronic". In addition, most individuals aligned with a "low-stable" trajectory indicative of minimal aggression in the first year following return from a combat deployment. A conditional model showed that lower posttraumatic stress and lower combat exposure characterized individuals aligned with the "low-stable" aggression trajectory relative to individuals aligned with "chronic" and "delayed" aggression trajectories. Implications for targeted intervention and future research are discussed.

Prognostic variables in high-risk cutaneous squamous cell carcinoma: a review.

Cutaneous squamous cell carcinoma (SCC) is a growing public health problem in the United States. A subset of high-risk SCC exhibits a more aggressive clinical trajectory including increased local recurrence and lymph node metastasis. However, there are no universally accepted criteria to help define and manage these patients. This review provides an overview of the high-risk features of cutaneous SCC, prognostic stratification of various staging systems and treatment options. It further examines the prognostic factors influencing the staging of cutaneous head and neck SCC.

Scarred for the Rest of My Career? Career-Long Effects of Abusive Leadership on Professional Athlete Aggression and Task Performance.

Based on the contention that leadership has sustained effects on followers even after the leader-follower relationship has ended, we investigated the career-long effects of abusive coach leadership on athlete aggression and task performance. Abusive leadership scores were derived from ratings by two independent raters' evaluations of coaches' biographies, and athlete aggression and task performance data were derived from objective sources. Data were obtained from players (N = 693) and coaches (N = 57) involved in the National Basketball Association (NBA) between the 2000-2001 and 2005-2006 seasons. Controlling for tenure, salary, team winning percentage, and absence due to injuries, multilevel modeling showed that exposure to abusive leadership influenced both the trajectory of psychological aggression and task performance over players' careers. These findings suggest that the effects of abusive leadership extend far longer than currently acknowledged, thus furthering our understanding of the nature and effects of abusive leadership.

Early Risk Predictors of Girls’ Indirect Aggression from Childhood to Early Adolescence in an At-Risk Sample

The present study aimed first to examine the trajectories of indirect aggression among girls from disadvantaged neighborhoods from childhood (M age = 8.38, SD = .91, range = 6.58–10.25) to early adolescence (M age = 11.28, SD = .93, range = 9.33–13.83), after controlling for physical aggression. Second, it aimed to identify possible individual, family, and peer risk factors, assessed in the early school years, which predispose subgroups of girls to use indirect aggression in an intense and persistent way. Three trajectories of indirect aggression were identified: 18.9 % (n = 57) of the girls followed a trajectory that started out at the mean and then increased (“mean-increasing”), 44.5 % (n = 134) of the girls followed a trajectory that started out at the mean and then decreased (“mean-decreasing”), and 36.5 % (n = 110) of the girls followed a trajectory that started out below the mean and then decreased (“low-decreasing”). Results from univariate analyses suggest that individual, family and peer risk factors predicted membership in the subgroup of girls who use indirect aggression more frequently and increasingly. However, in multivariate analyses, only the individual factor of surgency/extraversion predicted membership in this subgroup of girls. Hostile parent–child relationships also differentiated girls in the “mean-decreasing” group from the “low-decreasing” group. Interventions aimed at changing negative temperamental tendencies and interpersonal experiences with family and peers may break the cycle that reinforces frequent and persistent use of indirect aggression.

Poverty and behavior problems during early childhood

Poverty is a well-established risk factor for behavior problems, yet our understanding of putative family mediators during early childhood (i.e., before age 5 years) is limited. The present study investigated whether the association between poverty and behavior problems during early childhood is mediated simultaneously by perceived parenting, family dysfunction and/or maternal depression symptoms. Outcomes measures were high trajectories of physical aggression and hyperactivity between 1.5 and 5 years. Poverty was defined as living 2–4 years below the low-income thresholds defined by Statistics Canada. Using data from the first five rounds of the Quebec Longitudinal Study of Child Development, logistic regressions models showed that poverty was associated with a higher likelihood of being assigned to the high trajectory of physical aggression and hyperactivity. Overprotection and maternal depression symptoms mediated observed associations. Interventions targeting maternal depression, parenting, and poverty should help reducing children’s risk for early behavior problems.

Trait Impulsivity and Newlyweds' Marital Trajectories.

Despite the relationship of impulsivity with interpersonal dysfunction, including romantic relationship dysfunction, surprisingly little research has examined the degree to which impulsivity predicts how marriages unfold over time. The current study used data from 172 newlywed couples to examine spouses' impulsivity in relation to their 4-year trajectories of marital satisfaction, marital problems, relationship commitment, and verbal aggression, as well as their 10-year divorce rates. Hierarchical linear modeling indicated that husbands' and wives' impulsivity predicted their own intercepts of marital satisfaction and marital problems, reflecting lower levels of satisfaction and higher levels of problems. Wives' impulsivity also predicted their relationship commitment and their verbal aggression intercepts. No cross-spouse effects or effects on slopes were found, and impulsivity did not predict 10-year divorce rates. These findings indicate that the relationship distress associated with impulsivity begins early in marriage, and they suggest a need for further research on the processes by which impulsivity undermines marital quality.

Correlation of anemia status with worsening bowel damage as measured by Lémann Index in patients with Crohn's disease

BackgroundThere is evidence that anemia in Crohn's disease (CD) is a predictor of disease severity. AimTo evaluate if patterns of anemia over time showed correlation with aggressive disease trajectory, as characterized by change in Lémann Index (LI), which is a metric that quantifies bowel damage. MethodsCD patients with 5 year (y) follow-up from a prospective registry were included. LI was calculated from the first (LI1) and last (LI2) clinical encounters. The change in score (LI2–LI1) or the Delta LI (DLI) was recorded. Patterns of anemia, healthcare utilization and disease activity scores were analyzed. ResultsA total of 389 CD patients with 5y follow-up formed the study population [median age 40y (IQR: 31–53); 57.3% female; median disease duration 12y (IQR: 6–20.5), overall surgical exposure 69%]. Patients with anemia had significantly higher LI1, LI2, DLI and also significantly higher healthcare utilization and indices of disease activity, than patients without anemia (p<0.001). CD patients with anemia for any duration during the study had OR of 2.15 (95% CI 1.29–3.57, p=0.003) for worsening bowel damage over the 5y. ConclusionBased on a longitudinal analysis of CD patients, anemia status over time shows significant correlation with increasing Lémann index and aggressive disease trajectory.

Social and physical aggression trajectories from childhood through late adolescence: Predictors of psychosocial maladjustment at age 18.

This research examined whether following social and physical aggression trajectories across Grades 3-12 predicted psychological maladjustment. Teachers rated participants' (n = 287, 138 boys) aggressive behavior at the end of each school year. Following the 12th grade, psychosocial outcomes were measured: rule-breaking behaviors, internalizing symptoms, and narcissistic and borderline personality features. Following the highest social aggression trajectory predicted rule-breaking behavior; the medium social aggression trajectory was not a significant predictor of any outcome. Following the highest physical aggression trajectory predicted rule-breaking, internalizing symptoms, and narcissism, whereas the medium physical aggression trajectory predicted rule-breaking and internalizing symptoms.

The role of parental involvement in trajectories of aggression in children from 24 months to Pre-Kindergarten using growth curve models

The significant contribution of parental involvement in children's education to children's educational success is well supported. Yet less frequently studied is the influence of parental involvement on children's social-emotional development. Given that problem behaviors are negatively associated with child outcomes and that parental involvement is widely accepted as a conduit through which children's educational outcomes can be enhanced, it is important to examine this relationship.In this study, we examine the effect of early parental involvement on the social-emotional development of children. Using data from the Early Head Start Research and Evaluation study (EHSRE), we examine the within individual and between-individual differences in trajectories of aggression among children (N=1586) ages 24months through Prekindergarten. Contrary to hypotheses, after controlling for significant covariates (i.e., race, gender, poverty, mother's education, and adult male in the household), parental involvement was not related to aggression at 24months. In addition, change in aggression did not vary by level of parental involvement. Implications and directions for future research are discussed.

Supplemental Material for Social and Physical Aggression Trajectories From Childhood Through Late Adolescence: Predictors of Psychosocial Maladjustment at Age 18

Supplemental Material for Social and Physical Aggression Trajectories From Childhood Through Late Adolescence: Predictors of Psychosocial Maladjustment at Age 18

Costs and benefits of children's physical and relational aggression trajectories on peer rejection, acceptance, and friendships: Variations by aggression subtypes, gender, and age.

This study examined the associations between children's co-occurring relational and physical aggression trajectories and their peer relations (i.e., peer rejection, peer acceptance, and reciprocated friendships) from late childhood (Grade 4; Mage = 10.0) to early adolescence (Grade 8; Mage = 13.9). Using a sample of 477 children (240 girls), the findings indicated there were multiple heterogeneous subgroups of children who followed distinct co-occurring aggression trajectories. For each of these subgroups, multiple indices of their relational development were assessed and findings revealed notable group differences. These results have implications about the potential costs and benefits of aggression, and how its associations with children's peer relationships may vary as a function of aggression subtype, developmental timing, and gender.

Time-Varying Risk Factors and Sexual Aggression Perpetration Among Male College Students

PurposePreventing sexual aggression (SA) can be informed by determining if time-varying risk factors differentiate men who follow different sexual aggression risk trajectories. MethodsData are from a longitudinal study with 795 college males surveyed at the end of each of their 4 years of college in 2008–2011. Repeated measures general linear models tested if changes in risk factors corresponded with sexual aggression trajectory membership. ResultsChanges in the risk factors corresponded with SA trajectories. Men who came to college with a history of SA but decreased their perpetration likelihood during college showed concurrent decreases in sexual compulsivity, impulsivity, hostile attitudes toward women, rape supportive beliefs, perceptions of peer approval of forced sex, and perceptions of peer pressure to have sex with many different women, and smaller increases in pornography use over their college years. Conversely, men who increased levels of SA over time demonstrated larger increases in risk factors in comparison to other trajectory groups. ConclusionsThe odds that males engaged in sexual aggression corresponded with changes in key risk factors. Risk factors were not static and interventions designed to alter them may lead to changes in sexual aggression risk.

Developmental trajectories of aggression, prosocial behavior, and social-cognitive problem solving in emerging adolescents with clinically elevated attention-deficit/hyperactivity disorder symptoms.

Middle school is a critical yet understudied period of social behavioral risks and opportunities that may be particularly difficult for emerging adolescents with attention-deficit/hyperactivity disorder (ADHD) given their childhood social difficulties. Relatively few ADHD studies have examined social behavior and social-cognitive problem solving beyond the elementary years, or examined aspects of positive (prosocial) behavior. The current study examined how middle school students with clinically elevated ADHD symptoms differ from their non-ADHD peers on baseline (6th grade) and age-related changes in prosocial and aggressive behavior, and the extent to which social-cognitive problem solving strategies mediate these relations. Emerging adolescents with (n = 178) and without (n = 3,806) clinically elevated, teacher-reported ADHD-combined symptoms were compared longitudinally across 6th through 8th grades using parallel process latent growth curve modeling, accounting for student demographic characteristics, oppositional-defiant disorder (ODD) symptoms, deviant peer association, school climate, and parental monitoring. Sixth graders with elevated ADHD symptoms engaged in somewhat fewer prosocial behaviors (d = -0.44) and more aggressive behavior (d = 0.20) relative to their peers. These small social behavioral deficits decreased but were not normalized across the middle school years. Contrary to hypotheses, social-cognitive problem solving was not impaired in the ADHD group after accounting for co-occurring ODD symptoms and did not mediate the association between ADHD and social behavior during the middle school years. ADHD and social-cognitive problem solving contributed independently to social behavior, both in 6th grade and across the middle school years; the influence of social-cognitive problem solving on social behavior was highly similar for the ADHD and non-ADHD groups.