Biodiversity in changing environments: An external-driver internal-topology framework to guide intervention.

Accompanying the climate crisis is the more enigmatic biodiversity crisis. Rapid reorganization of biodiversity due to global environmental change has defied prediction and tested the basic tenets of conservation and restoration. Conceptual and practical innovation is needed to support decision making in the face of these unprecedented shifts. Critical questions include: How can we generalize biodiversity change at the community level? When are systems able to reorganize and maintain integrity, and when does abiotic change result in collapse or restructuring? How does this understanding provide a template to guide when and how to intervene in conservation and restoration? To this end, we frame changes in community organization as the modulation of external abiotic drivers on the internal topology of species interactions, using plant-plant interactions in terrestrial communities as a starting point. We then explore how this framing can help translate available data on species abundance and trait distributions to corresponding decisions in management. Given the expectation that community response and reorganization are highly complex, the external-driver internal-topology (EDIT) framework offers a way to capture general patterns of biodiversity that can help guide resilience and adaptation in changing environments.

High-grade squamous intraepithelial lesion cervicovaginal paps with negative high-risk HPV testing, a prospective study with histological follow-up.

BACKGROUND: High-risk human papillomavirus (hrHPV) testing has become integral in the screening and treatment protocols for cervical neoplasia. Stand-alone HPV testing is advocated as a screening tool for cervical neoplasia. However, negative hrHPV tests with diagnosis of high-grade squamous intraepithelial lesion or worse (≥HSIL) have been reported. We report our experience with paps diagnosed as HSIL, negative hrHPV testing, and subsequent follow-up. METHODS: Of 303 women with HSIL diagnosed on ThinPrep pap between 2019 and 2023, 84 (28%) were tested for hrHPV by Roche Cobas. Repeat testing was performed at a referral center. Immunohistochemistry (IHC) for p16 was performed on follow-up biopsies and hrHPV in-situ hybridization. RESULTS: Of 84 HSIL cases, 8 were hrHPV negative. Follow-up biopsies available in 7 cases were ≥HSIL (1 with invasive squamous cell carcinoma, 1 endocervical adenocarcinoma in situ). Follow-up HSIL was found on additional cases of HPV negative atypical glandular cells favor neoplastic and atypical squamous cells favor HSIL. IHC for p16 was positive on all biopsies. hrHPV FISH was negative. CONCLUSIONS: Our experience with hrHPV testing by Roche Cobas demonstrates that some morphologically diagnostic HSIL paps are hrHPV negative: 8.3% of HSIL paps with subsequent histological HSIL were HPV negative. The index case caused concern among our clinical colleagues. Positive staining for p16 is highly suggestive of HPV induced disease. Possible reasons for negative hrHPV testing could include non-hrHPV types, low HPV DNA levels, or HPV types not included in the Cobas testing panel.

Seed bank bias: Differential tracking of functional traits in the seed bank and vegetation across a gradient.

A goal in trait-based ecology is to understand and predict plant community responses to environmental change; however, diversity stored within seed banks that may expand or limit these responses is typically overlooked. If seed banks store attributes that are more advantageous or vulnerable under future conditions, they could impact community adaptability to change and disturbance. We explored compositional differences between seed banks and vegetation (i.e., seed bank bias) across a 12-site gradient of increasingly higher and older soil terraces, asking: How do seed banks contribute to taxonomic and functional composition, and what do shifts in seed bank biases along the gradient (i.e., tracking) reveal about the processes driving seed bank variation and its implications for community adaptability? Across the gradient, seed banks stored distinct pools of species that added to species richness but not functional dispersion. Seed banks were generally biased toward short-life histories and "fast" species with small seeds, thinner and more acquisitive roots, and lower root biomass allocation; however, trait means in the seed bank and vegetation sometimes shifted along the gradient, amplifying or reversing these biases. For example, species with higher specific leaf area (tied to rapid resource acquisition) tended to dominate vegetation on lower soil terraces, but were more common in the seed bank on higher terraces-at least when patterns were weighted by species' relative abundances. Although seed banks were generally characterized by "fast" attributes, observed shifts in seed bank biases across the gradient-particularly in leaf traits-demonstrate that environment can impact stored diversity and, consequently, our expectations for future vegetative turnover. The seed bank bias patterns that we characterized could be the result of many potential processes, including environment- or trait-driven variation in seed bank inputs (seed production, dispersal) or losses (seed desiccation, germination), and may have important implications for a system's adaptive capacity. Only by integrating seed banks into the functional ecology agenda will we be able to unpack these processes and use seed banks more effectively in both prediction and ecosystem management.

Plant traits are differentially linked to performance in a semiarid ecosystem.

A central principle in trait-based ecology is that trait variation has an adaptive value. However, uncertainty over which plant traits influence individual performance across environmental gradients may limit our ability to use traits to infer ecological processes at larger scales. To better understand which traits are linked to performance under different precipitation regimes, we measured above- and belowground traits, growth, and reproductive allocation for four annual and four perennial species from a coastal sage scrub community in California under conditions of 50%, 100%, and 150% ambient precipitation. Across water treatments, annual species displayed morphological trait values consistent with high rates of resource acquisition (e.g., low leaf mass per area, low root tissue density, high specific root length), and aboveground measures of resource acquisition (including photosynthetic rate and leaf N concentration) were positively associated with plant performance (reproductive allocation). Results from a structural equation model demonstrated that leaf traits explained 38% of the variation in reproductive allocation across the water gradient in annual species, while root traits accounted for only 6%. Although roots play a critical role in water uptake, more work is needed to understand the mechanisms by which root trait variation can influence performance in water-limited environments. Perennial species showed lower trait plasticity than annuals across the water gradient and were more variable as a group in terms of trait-performance relationships, indicating that species rely on different functional strategies to respond to drought. Our finding that species identity drives much of the variation in trait values and trait-performance relationships across a water gradient may simplify efforts to model ecological processes, such as productivity, that are potentially influenced by environmentally induced shifts in trait values.

Leaf traits and performance vary with plant age and water availability in Artemisia californica.

BACKGROUND AND AIMS: Leaf functional traits are strongly tied to growth strategies and ecological processes across species, but few efforts have linked intraspecific trait variation to performance across ontogenetic and environmental gradients. Plants are believed to shift towards more resource-conservative traits in stressful environments and as they age. However, uncertainty as to how intraspecific trait variation aligns with plant age and performance in the context of environmental variation may limit our ability to use traits to infer ecological processes at larger scales. METHODS: We measured leaf physiological and morphological traits, canopy volume and flowering effort for Artemisia californica (California sagebrush), a dominant shrub species in the coastal sage scrub community, under conditions of 50, 100 and 150 % ambient precipitation for 3 years. KEY RESULTS: Plant age was a stronger driver of variation in traits and performance than water availability. Older plants demonstrated trait values consistent with a more conservative resource-use strategy, and trait values were less sensitive to drought. Several trait correlations were consistent across years and treatments; for example, plants with high photosynthetic rates tended to have high stomatal conductance, leaf nitrogen concentration and light-use efficiency. However, the trade-off between leaf construction and leaf nitrogen evident in older plants was absent for first-year plants. While few traits correlated with plant growth and flowering effort, we observed a positive correlation between leaf mass per area and performance in some groups of older plants. CONCLUSIONS: Overall, our results suggest that trait sensitivity to the environment is most visible during earlier stages of development, after which intraspecific trait variation and relationships may stabilize. While plant age plays a major role in intraspecific trait variation and sensitivity (and thus trait-based inferences), the direct influence of environment on growth and fecundity is just as critical to predicting plant performance in a changing environment.

PET Measures of D1, D2, and DAT Binding Are Associated With Heightened Tactile Responsivity in Rhesus Macaques: Implications for Sensory Processing Disorder.

Sensory processing disorder (SPD), a developmental regulatory condition characterized by marked under- or over-responsivity to non-noxious sensory stimulation, is a common but poorly understood disorder that can profoundly affect mood, cognition, social behavior and adaptive life skills. Little is known about the etiology and neural underpinnings. Clinical research indicates that children with SPD show greater prevalence of difficulties in complex cognitive behavior including working memory, behavioral flexibility, and regulation of sensory and affective functions, which are related to prefrontal cortex (PFC), striatal, and midbrain regions. Neuroimaging may provide insight into mechanisms underlying SPD, and animal experiments provide important evidence that is not available in human studies. Rhesus monkeys (N = 73) were followed over a 20-year period from birth into old age. We focused on a single sensory modality, the tactile system, measured at 5-7 years, because of its critical importance for nourishment, attachment, and social reward in development. Positron emission tomography imaging was conducted at ages 12-18 years to quantify the availability of the D1 and D2 subtypes of the DA receptor (D1R and D2R), and the DA transporter (DAT). Heightened tactile responsivity was related to (a) elevated D1R in PFC overall, including lateral, ventrolateral, medial, anterior cingulate (aCg), frontopolar, and orbitofrontal (OFC) subregions, as well as nucleus accumbens (Acb), (b) reduced D2R in aCg, OFC, and substantia nigra/ventral tegmental area, and (c) elevated DAT in putamen. These findings suggest a mechanism by which DA pathways may be altered in SPD. These pathways are associated with reward processing and pain regulation, providing top-down regulation of sensory and affective processes. The balance between top-down cognitive control in the PFC-Acb pathway and bottom-up motivational function of the VTA-Acb-PFC pathway is critical for successful adaptive function. An imbalance in these two systems might explain DA-related symptoms in children with SPD, including reduced top-down regulatory function and exaggerated responsivity to stimuli. These results provide more direct evidence that SPD may involve altered DA receptor and transporter function in PFC, striatal, and midbrain regions. More work is needed to extend these results to humans.

A research agenda for seed-trait functional ecology.

Trait-based approaches have improved our understanding of plant evolution, community assembly and ecosystem functioning. A major challenge for the upcoming decades is to understand the functions and evolution of early life-history traits, across levels of organization and ecological strategies. Although a variety of seed traits are critical for dispersal, persistence, germination timing and seedling establishment, only seed mass has been considered systematically. Here we suggest broadening the range of morphological, physiological and biochemical seed traits to add new understanding on plant niches, population dynamics and community assembly. The diversity of seed traits and functions provides an important challenge that will require international collaboration in three areas of research. First, we present a conceptual framework for a seed ecological spectrum that builds upon current understanding of plant niches. We then lay the foundation for a seed-trait functional network, the establishment of which will underpin and facilitate trait-based inferences. Finally, we anticipate novel insights and challenges associated with incorporating diverse seed traits into predictive evolutionary ecology, community ecology and applied ecology. If the community invests in standardized seed-trait collection and the implementation of rigorous databases, major strides can be made at this exciting frontier of functional ecology.

Rapid root responses of seedlings exposed to a postdrought water pulse.

PREMISE OF THE STUDY: Mediterranean-type climate ecosystems experience significant variability in precipitation within and across years and may be characterized by periods of extreme drought followed by a brief, high-intensity precipitation pulse. Rapid root growth could be a key factor in effective utilization of precipitation pulses, leading to higher rates of seedling establishment. Changes in root growth rate are rarely studied, however, and patterns in seedling root traits are not well explored. We investigated the influence of an extreme postdrought precipitation event on seedlings that occur in southern California coastal sage scrub. METHODS: We measured root elongation rate, root tip appearance rate, new leaf appearance rate, and canopy growth rate on 18 mediterranean species from three growth forms. KEY RESULTS: Root elongation rate responded more strongly to the precipitation pulse than did root tip appearance rate and either metric of aboveground growth. The majority of species exhibited a significant change in root growth rate within 1 week of the pulse. Responses varied in rapidity and magnitude across species, however, and were not generally predictable based on growth form. CONCLUSIONS: While the majority of species exhibited shifts in belowground growth following the pulse, the direction and magnitude of these morphological responses were highly variable within growth form. Understanding the implications of these different response strategies for plant fitness is a crucial next step to forecasting community dynamics within ecosystems characterized by resource pulses.

Sensory Processing in Rhesus Monkeys: Developmental Continuity, Prenatal Treatment, and Genetic Influences.

Neonatal sensory processing (tactile and vestibular function) was tested in 78 rhesus macaques from two experiments. At ages 4-5 years, striatal dopamine D2 receptor binding was examined using positron emission tomography. At ages 5-7 years, adult sensory processing was assessed. Findings were: (a) prenatal stress exposure yielded less optimal neonatal sensory processing; (b) animals carrying the short rh5-HTTLPR allele had less optimal neonatal sensory scores than monkeys homozygous for the long allele; (c) neonatal sensory processing was significantly related to striatal D2 receptor binding for carriers of the short allele, but not for animals homozygous for the long allele; and (d) there was moderate developmental continuity in sensory processing from the neonatal period to adulthood.

Revisiting the Holy Grail: using plant functional traits to understand ecological processes.

One of ecology's grand challenges is developing general rules to explain and predict highly complex systems. Understanding and predicting ecological processes from species' traits has been considered a 'Holy Grail' in ecology. Plant functional traits are increasingly being used to develop mechanistic models that can predict how ecological communities will respond to abiotic and biotic perturbations and how species will affect ecosystem function and services in a rapidly changing world; however, significant challenges remain. In this review, we highlight recent work and outstanding questions in three areas: (i) selecting relevant traits; (ii) describing intraspecific trait variation and incorporating this variation into models; and (iii) scaling trait data to community- and ecosystem-level processes. Over the past decade, there have been significant advances in the characterization of plant strategies based on traits and trait relationships, and the integration of traits into multivariate indices and models of community and ecosystem function. However, the utility of trait-based approaches in ecology will benefit from efforts that demonstrate how these traits and indices influence organismal, community, and ecosystem processes across vegetation types, which may be achieved through meta-analysis and enhancement of trait databases. Additionally, intraspecific trait variation and species interactions need to be incorporated into predictive models using tools such as Bayesian hierarchical modelling. Finally, existing models linking traits to community and ecosystem processes need to be empirically tested for their applicability to be realized.

Seedling root responses to soil moisture and the identification of a belowground trait spectrum across three growth forms.

Root trait variation and plasticity could be key factors differentiating plant performance under drought. However, water manipulation and root measurements are rarely coupled empirically across growth forms to identify whether belowground strategies are generalizable across species. We measured seedling root traits across three moisture levels in 18 Mediterranean forbs, grasses, and woody species. Drought increased the root mass fraction (RMF) and decreased the relative proportion of thin roots (indicated by increased root diameters and decreased specific root length (SRL)), rates of root elongation and growth, plant nitrogen uptake, and plant growth. Although responses varied across species, plasticity was not associated with growth form. Woody species differed from forbs and grasses in many traits, but herbaceous groups were similar. Across water treatments, trait correlations suggested a single spectrum of belowground trade-offs related to resource acquisition and plant growth. While effects of SRL and RMF on plant growth shifted with drought, root elongation rate consistently represented this spectrum. We demonstrate that general patterns of root morphology and plasticity are identifiable across diverse species. Root trait measurements should enhance our understanding of belowground strategy and performance across growth forms, but it will be critical to incorporate plasticity and additional aspects of root function into these efforts.

Do key dimensions of seed and seedling functional trait variation capture variation in recruitment probability?

Seedling recruitment is a critical driver of population dynamics and community assembly, yet we know little about functional traits that define different recruitment strategies. For the first time, we examined whether trait relatedness across germination and seedling stages allows the identification of general recruitment strategies which share core functional attributes and also correspond to recruitment outcomes in applied settings. We measured six seed and eight seedling traits (lab- and field-collected, respectively) for 47 varieties of dryland grasses and used principal component analysis (PCA) and cluster analysis to identify major dimensions of trait variation and to isolate trait-based recruitment groups, respectively. PCA highlighted some links between seed and seedling traits, suggesting that relative growth rate and root elongation rate are simultaneously but independently associated with seed mass and initial root mass (first axis), and with leaf dry matter content, specific leaf area, coleoptile tissue density and germination rate (second axis). Third and fourth axes captured separate tradeoffs between hydrothermal time and base water potential for germination, and between specific root length and root mass ratio, respectively. Cluster analysis separated six recruitment types along dimensions of germination and growth rates, but classifications did not correspond to patterns of germination, emergence or recruitment in the field under either of two watering treatments. Thus, while we have begun to identify major threads of functional variation across seed and seedling stages, our understanding of how this variation influences demographic processes-particularly germination and emergence-remains a key gap in functional ecology.

Body satisfaction, thin-ideal internalization, and perceived pressure to be thin among Canadian women: The role of acculturation and religiosity.

In an online study, 143 Canadian women of various religious backgrounds completed measures of acculturation, religiosity, body satisfaction, internalization of the thin ideal, perceived pressure from media, and manner of dress. Heritage acculturation correlated with appearance satisfaction, but not weight satisfaction. After accounting for BMI and social desirability, higher heritage acculturation and lower mainstream acculturation were associated with lower perceived pressure from media. Thus, heritage acculturation across religious denominations may serve as a buffer against appearance dissatisfaction and perceived media pressure. Manner of dress among the Muslim subgroup and its relation to religiosity and acculturation were also assessed. Muslim women who dressed in greater accordance with Islamic principles reported lower heritage acculturation and greater religiosity. Thus, Muslim women's manner of dress was related to their religiosity and the extent to which they embraced cultural values. These findings are discussed in terms of the possible distinctions between heritage acculturation and religiosity.

The effects of chronic alcohol self-administration on serotonin-1A receptor binding in nonhuman primates.

BACKGROUND: Previous studies have found interrelationships between the serotonin system and alcohol self-administration. The goal of this work was to directly observe in vivo effects of chronic ethanol self-administration on serotonin 5-HT1A receptor binding with [(18)F]mefway PET neuroimaging in rhesus monkeys. Subjects were first imaged alcohol-naïve and again during chronic ethanol self-administration to quantify changes in 5-HT1A receptor binding. METHODS: Fourteen rhesus monkey subjects (10.7-12.8 years) underwent baseline [(18)F]mefway PET scans prior to alcohol exposure. Subjects then drank gradually increasing ethanol doses over four months as an induction period, immediately followed by at least nine months ad libidum ethanol access. A post [(18)F]mefway PET scan was acquired during the final three months of ad libidum ethanol self-administration. 5-HT1A receptor binding was assayed with binding potential (BPND) using the cerebellum as a reference region. Changes in 5-HT1A binding during chronic ethanol self-administration were examined. Relationships of binding metrics with daily ethanol self-administration were also assessed. RESULTS: Widespread increases in 5-HT1A binding were observed during chronic ethanol self-administration, independent of the amount of ethanol consumed. A positive correlation between 5-HT1A binding in the raphe nuclei and average daily ethanol self-administration was also observed, indicating that baseline 5-HT1A binding in this region predicted drinking levels. CONCLUSIONS: The increase in 5-HT1A binding levels during chronic ethanol self-administration demonstrates an important modulation of the serotonin system due to chronic alcohol exposure. Furthermore, the correlation between 5-HT1A binding in the raphe nuclei and daily ethanol self-administration indicates a relationship between the serotonin system and alcohol self-administration.

Changes in the α4ß2* nicotinic acetylcholine system during chronic controlled alcohol exposure in nonhuman primates.

BACKGROUND: The precise nature of modifications to the nicotinic acetylcholine receptor (nAChR) system in response to chronic ethanol exposure is poorly understood. The present work used PET imaging to assay α4ß2* nAChR binding levels of eight rhesus monkeys before and during controlled chronic ethanol intake. METHODS: [(18)F]Nifene PET scans were conducted prior to alcohol exposure, and then again after at least 8 months controlled ethanol exposure, including 6 months at 1.5 g/kg/day following a dose escalation period. Receptor binding levels were quantified with binding potentials (BPND) using the cerebellum as a reference region. Alcohol self-administration was assessed as average daily alcohol intake during a 2 month free drinking period immediately following controlled alcohol. RESULTS: Significant decreases in α4ß2* nAChR binding were observed in both frontal and insular cortex in response to chronic ethanol exposure. During chronic alcohol exposure, BPND in the lateral geniculate region correlated positively with the amount of alcohol consumed during free drinking. CONCLUSIONS: The observed decreases in nAChR availability following chronic alcohol consumption suggest alterations to this receptor system in response to repeated alcohol administration, making this an important target for further study in alcohol abuse and alcohol and nicotine codependence.

Moderate-level prenatal alcohol exposure induces sex differences in dopamine d1 receptor binding in adult rhesus monkeys.

BACKGROUND: We examined the effects of moderate prenatal alcohol exposure and/or prenatal stress exposure on (D1 R) binding in a non human primate model. The dopamine D1 R is involved in executive function, and it may play a role in cognitive behavioral deficits associated with prenatal alcohol and/or stress exposure. Little is known, however, about the effects of prenatal alcohol and/or stress exposure on the D1 R. We expected that prenatal insults would lead to alterations in D1 R binding in prefrontal cortex (PFC) and striatum in adulthood. METHODS: Rhesus macaque females were randomly assigned to moderate alcohol exposure and/or mild prenatal stress as well as a control condition during pregnancy. Thirty-eight offspring were raised identically and studied as adults by noninvasive in vivo neuroimaging using positron emission tomography with the D1 antagonist radiotracer [(11) C]SCH 23390. Radiotracer binding in PFC and striatum was evaluated by 2 (alcohol) × 2 (stress) × 2 (sex) analysis of variance. RESULTS: In PFC, a significant alcohol × sex interaction was observed with prenatal alcohol exposure leading to increased [(11) C]SCH 23390 binding in male monkeys. No main effect of prenatal alcohol or prenatal stress exposure was observed. CONCLUSIONS: These results suggest that prenatal alcohol exposure results in long-term increases in prefrontal dopamine D1 R binding in males. This may help explain gender differences in the prevalence of neurodevelopmental disorders consequent to prenatal alcohol exposure.

Moderate-level prenatal alcohol exposure enhances acoustic startle magnitude and disrupts prepulse inhibition in adult rhesus monkeys.

BACKGROUND: Prenatal alcohol exposure can contribute to a wide range of neurodevelopmental impairments in children and adults including behavioral and neuropsychiatric disorders. In rhesus monkeys, we examined whether moderate-level prenatal alcohol exposure would alter acoustic startle responses and prepulse inhibition (PPI) of the acoustic startle. PPI is a highly quantifiable measure of inhibitory neural processes or sensorimotor gating associated with neuropsychiatric disorders. METHODS: Acoustic startle and PPI of the acoustic startle were tested in 37 adult rhesus monkeys (Macaca mulatta) from 4 experimental conditions: (i) moderate-level prenatal alcohol-exposed, (ii) prenatally stressed, (iii) moderate-level prenatal alcohol-exposed + prenatally stressed, and (iv) sucrose controls. RESULTS: Prenatal alcohol-exposed monkeys showed a higher magnitude of acoustic startle response and disrupted PPI compared with monkeys not exposed to alcohol prenatally. Monkeys in all conditions showed higher hypothalamic-pituitary-adrenocortical (HPA) axis responses after undergoing the startle procedure, but HPA responses were unrelated to startle response magnitude, latency, or PPI. CONCLUSIONS: Finding altered PPI in monkeys prenatally exposed to a moderate dose of alcohol suggests that reduced sensorimotor gating is 1 effect of prenatal alcohol exposure. Because reduced sensorimotor gating is observed in many neuropsychiatric disorders, sensorimotor gating deficits could be an aspect of the comorbidity between fetal alcohol spectrum disorder and mental health conditions.

Prenatal stress induces increased striatal dopamine transporter binding in adult nonhuman primates.

BACKGROUND: To determine the effects in adult offspring of maternal exposure to stress and alcohol during pregnancy, we imaged striatal and midbrain dopamine transporter (DAT) binding by positron emission tomography in rhesus monkeys (Macaca mulatta). We also evaluated the relationship between DAT binding and behavioral responses previously found to relate to dopamine D2 receptor density (responsivity to tactile stimuli, performance on a learning task, and behavior during a learning task). METHODS: Subjects were adult offspring derived from a 2 × 2 experiment in which pregnant monkeys were randomly assigned to control, daily mild stress exposure (acoustic startle), voluntary consumption of moderate-level alcohol, or both daily stress and alcohol. Adult offspring (n = 38) were imaged by positron emission tomography with the DAT ligand [(18)F]2ß-carbomethoxy-3ß-(4-chlorophenyl)-8-(2-fluoroethyl)-nortropane ([(18)F]FECNT). RESULTS: Results showed that prenatal stress yielded an overall increase of 15% in [(18)F]FECNT binding in the striatum (p = .016), 17% greater binding in the putamen (p = .012), and 13% greater binding in the head of the caudate (p = .028) relative to animals not exposed to prenatal stress. Striatal [(18)F]FECNT binding correlated negatively with habituation to repeated tactile stimulation and positively with tactile responsivity. There were no significant effects of prenatal alcohol exposure on [(18)F]FECNT binding. CONCLUSIONS: Maternal exposure to mild daily stress during pregnancy yielded increases in striatal DAT availability that were apparent in adult offspring and were associated with behavioral characteristics reflecting tactile hyperresponsivity, a condition associated with problem behaviors in children.