173 research outputs found

    Childhood poly-victimization and perceived family environment

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    There is a growing body of evidence demonstrating the necessity of examining multiple victimizations when studying childhood victimization histories. Several studies have found poly-victimization (i.e., high cumulative levels of victimization) common in non-clinical samples and associated with greater trauma symptomatology than experiencing a single type of victimization (Finkelhor, Ormrod, & Turner, 2007; Richmond, Elliott, Pierce, Aspelmeier, & Alexander, 2009; Saunders, 2003). This study examined the relative contribution of six different categories of childhood victimization and poly-victimization in predicting the Conflict and Cohesion subscale scores of the Family Environment Scale (FES). In a sample of 330 female college undergraduates, the results showed that victimization was common in a non-clinical sample, and most participants who endorsed one type of victimization also endorsed multiple types. Poly-victimization accounted for significant proportions of variability in participants\u27 perceptions of their family conflict and cohesion, but these contributions were small to moderate. Finally, polyvictimization and the simultaneous entry of all six categories of victimization accounted for large, and statistically significant, amounts of variance for perceived family conflict and cohesion

    Virtual reconstruction of the endocranial anatomy of the early Jurassic marine crocodylomorph Pelagosaurus typus (Thalattosuchia)

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    Thalattosuchia is a radiation of aquatic crocodylomorphs that attained a worldwide distribution at low latitudes during the Early Jurassic—Early Cretaceous (Mannion et al., 2015). They are characterized by having a longirostrine skull morphology (long, narrow snout), although some taxa possessed relatively shorter and more robust snouts (e.g., Dakosaurus; Gasparini, Pol & Spalletti, 2006). The group is divided into two major clades, the teleosauroids, which were ‘gavial-like’ near shore predators, and the highly-derived pelagic metriorhynchoids (i.e., metriorhynchids), which exhibited modified flipper-like forelimbs, a crescentic fish-like tail, and loss of dermal armour. The morphology, phylogeny, and evolutionary dynamics of the Thalattosuchia has been under intense investigation over the past decade (e.g., Mueller-Töwe, 2005; Mueller-Töwe, 2006; Jouve, 2009; Pierce, Angielczyk & Rayfield, 2009a; Pol & Gasparini, 2009; Young & De Andrade, 2009; Young et al., 2010; Young, Bell & Brusatte, 2011; Martin & Vincent, 2013; Stubbs et al., 2013; Cau, 2014; Martin et al., 2014; Jouve et al., 2016; Young et al., 2016) with some recent studies suggesting that thalattosuchians may be relatively early diverging members of the Crocodyliformes (e.g., Wilberg, 2015a). Moreover, there has been increasing interest in reconstructing their functional paleoecology, with studies focusing on feeding mechanics and niche partitioning (e.g., Pierce, Angielczyk & Rayfield, 2009b; De Andrade et al., 2010; Young et al., 2010; Stubbs et al., 2013; Young et al., 2013), as well as adaptations for aquatic locomotion (e.g., Hua, 1994; Hua & De Buffrenil, 1996; Hua, 2003; Molnar et al., 2015)

    Combining geometric morphometrics and finite element analysis with evolutionary modeling:towards a synthesis

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    <p>Geometric morphometrics (GM) and finite element analysis (FEA) are increasingly common techniques for the study of form and function. We show how principles of quantitative evolution in continuous phenotypic traits can link the two techniques, allowing hypotheses about the relative importance of different functions to be tested in a phylogenetic and evolutionary framework. Finite element analysis is used to derive quantitative surfaces that describe the comparative performance of different morphologies in a morphospace derived from GM. The combination of two or more performance surfaces describes a quantitative adaptive landscape that can be used to predict the direction morphological evolution would take if a combination of functions was selected for. Predicted paths of evolution also can be derived for hypotheses about the relative importance of multiple functions, which can be tested against evolutionary pathways that are documented by phylogenies or fossil sequences. Magnitudes of evolutionary trade-offs between functions can be estimated using maximum likelihood. We apply these methods to an earlier study of carapace strength and hydrodynamic efficiency in emydid turtles. We find that strength and hydrodynamic efficiency explain about 45% of the variance in shell shape; drift and other unidentified functional factors are necessary to explain the remaining variance. Measurement of the proportional trade-off between shell strength and hydrodynamic efficiency shows that throughout the Cenozoic aquatic turtles generally sacrificed strength for streamlining and terrestrial species favored stronger shells; this suggests that the selective regime operating on small to mid-sized emydids has remained relatively static.</p> <p>SUPPLEMENTAL DATA—Supplemental materials are available for this article for free at <a href="http://www.tandfonline.com/UJVP" target="_blank">www.tandfonline.com/UJVP</a></p> <p>Citation for this article: Polly, P. D., C. T. Stayton, E. R. Dumont, S. E. Pierce, E. J. Rayfield, and K. D. Angielczyk. 2016. Combining geometric morphometrics and finite element analysis with evolutionary modeling: towards a synthesis. Journal of Vertebrate Paleontology. DOI: 10.1080/02724634.2016.1111225.</p

    Ecological opportunity and the rise and fall of crocodylomorph evolutionary innovation

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    Understanding the origin, expansion and loss of biodiversity is fundamental to evolutionary biology. The approximately 26 living species of crocodylomorphs (crocodiles, caimans, alligators and gharials) represent just a snapshot of the group's rich 230-million-year history, whereas the fossil record reveals a hidden past of great diversity and innovation, including ocean and land-dwelling forms, herbivores, omnivores and apex predators. In this macroevolutionary study of skull and jaw shape disparity, we show that crocodylomorph ecomorphological variation peaked in the Cretaceous, before declining in the Cenozoic, and the rise and fall of disparity was associated with great heterogeneity in evolutionary rates. Taxonomically diverse and ecologically divergent Mesozoic crocodylomorphs, like marine thalattosuchians and terrestrial notosuchians, rapidly evolved novel skull and jaw morphologies to fill specialized adaptive zones. Disparity in semi-aquatic predatory crocodylians, the only living crocodylomorph representatives, accumulated steadily, and they evolved more slowly for most of the last 80 million years, but despite their conservatism there is no evidence for long-term evolutionary stagnation. These complex evolutionary dynamics reflect ecological opportunities, that were readily exploited by some Mesozoic crocodylomorphs but more limited in Cenozoic crocodylians.Sampling. We sample 240 crocodylomorph skulls and 204 lower jaws Shape analyses. Disparity was quantified using 2-D geometric morphometrics, with a mixed landmark/semi-landmarks approach. Phylogeny. A composite crocodylomorph supertree was assembled . Disparity. Disparity was quantified using custom code and the R package dispRity. Evolutionary rates. Rates of evolution were analysed in a Bayesian framework based on the multivariate variable-rates model in BayesTraits

    Mechanized Metatheory for the Masses: The \u3cb\u3ePOPLMARK\u3c/b\u3e Challenge

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    How close are we to a world where every paper on programming languages is accompanied by an electronic appendix with machinechecked proofs? We propose an initial set of benchmarks for measuring progress in this area. Based on the metatheory of System F, a typed lambda-calculus with second-order polymorphism, subtyping, and records, these benchmarks embody many aspects of programming languages that are challenging to formalize: variable binding at both the term and type levels, syntactic forms with variable numbers of components (including binders), and proofs demanding complex induction principles. We hope that these benchmarks will help clarify the current state of the art, provide a basis for comparing competing technologies, and motivate further research

    Multiple Forensic Interviews During Investigations of Child Sexual Abuse: A Cost-Effectiveness Analysis

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    In cases of suspected child sexual abuse (CSA) some professionals routinely recommend multiple interviews by the same interviewer because any additional details provided might improve decision-making and increase perpetrator convictions. We analyzed alternative policies about child interviewing to estimate the probability that a policy of all children receiving multiple interviews will increase criminal convictions and better protect children. Using decision analysis, we prepared a decision tree reflecting the structure through which a case of possible CSA passes through the health care, welfare, and legal systems with an estimated probability of conviction of the offender. We reviewed the CSA disclosure, criminal justice, and child welfare literature to obtain estimates for the median and range of rates for the steps of disclosure, substantiation, criminal charges, and conviction. Using the R statistical package, our decision analysis model was populated using literature-based estimates. Once the model was populated, we simulated the experiences of 1,000 cases at 250 sets of plausible parameter values representing different hypothetical communities. Multiple interviews increase the likelihood that an offender will be convicted by 6.1% in the average community. Simulations indicate that a policy in which all children seen for a CSA medical evaluation receive multiple interviews would cost an additional $100,000 for each additional conviction. We estimate that approximately 17 additional children would need to be interviewed on more than one occasion to yield one additional conviction. A policy of multiple interviews has implications for the children, for the costs of care, for protecting other children, and for the risk of false prosecution

    Cryptic complexity in felid vertebral evolution: shape differentiation and allometry of the axial skeleton

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    Members of the mammalian family Felidae (extant and extinct cats) are grossly phenotypically similar, but display a 300-fold range in body size, from less than 1 kg to more than 300 kg. In addition to differences in body mass, felid species show dietary and locomotory specializations that correlate to skull and limb osteological measurements, such as shape or cross-sectional area. However, ecological correlates to the axial skeleton are yet untested. Here, we build on previous studies of the biomechanical and morphological evolution of the felid appendicular skeleton by conducting a quantitative analysis of morphology and allometry in the presacral vertebral column across extant cats. Our results demonstrate that vertebral columns of arboreal, scansorial and terrestrial felids significantly differ in morphology, specifically in the lumbar region, while no distinction based on dietary specialization was found. Body size significantly influences vertebral morphology, with clear regionalization of allometry along the vertebral column, suggesting that anterior (cervicals and thoracics) and posterior (lumbar) vertebrae may be independently subjected to distinct selection pressures

    Digit and Ungual Morphology Suggest Adaptations for Scansoriality in the Late Carboniferous Eureptile Anthracodromeus longipes

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    A new skeleton of the exceedingly rare, late Carboniferous eureptile Anthracodromeus longipes (Carroll and Baird, 1972), reveals the presence of a reduced phalangeal count in the manus and pedes and uniquely recurved unguals. With these data, we quantitatively evaluate the locomotor ecology of Anthracodromeus using morphometric analyses of the phalangeal proportions, ungual curvature, and ungual shape. Our findings indicate that the anatomy of Anthracodromeus likely facilitated scansorial clinging to some degree via distally recurved unguals and increased surface area of the large manus and pes. This suggests that Anthracodromeus was among the earliest amniotes to show climbing abilities, pushing back the origins of scansoriality by at least 17 million years. It further suggests that scansoriality arose soon after the origin of amniotes, allowing them to exploit a wide range of novel terrestrial niches
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