Building a Bird: Musculoskeletal Modeling and Simulation of Wing-Assisted Incline Running during Avian Ontogeny

Flapping flight is the most power-demanding mode of locomotion, associated with a suite of anatomical specializations in extant adult birds. In contrast, many developing birds use their forelimbs to negotiate environments long before acquiring “flight adaptations,” recruiting their developing wings to continuously enhance leg performance and, in some cases, fly. How does anatomical development influence these locomotor behaviors? Isolating morphological contributions to wing performance is extremely challenging using purely empirical approaches. However, musculoskeletal modeling and simulation techniques can incorporate empirical data to explicitly examine the functional consequences of changing morphology by manipulating anatomical parameters individually and estimating their effects on locomotion. To assess how ontogenetic changes in anatomy affect locomotor capacity, we combined existing empirical data on muscle morphology, skeletal kinematics, and aerodynamic force production with advanced biomechanical modeling and simulation techniques to analyze the ontogeny of pectoral limb function in a precocial ground bird (Alectoris chukar). Simulations of wing-assisted incline running (WAIR) using these newly developed musculoskeletal models collectively suggest that immature birds have excess muscle capacity and are limited more by feather morphology, possibly because feathers grow more quickly and have a different style of growth than bones and muscles. These results provide critical information about the ontogeny and evolution of avian locomotion by (i) establishing how muscular and aerodynamic forces interface with the skeletal system to generate movement in morphing juvenile birds, and (ii) providing a benchmark to inform biomechanical modeling and simulation of other locomotor behaviors, both across extant species and among extinct theropod dinosaurs

An Economic Valuation of Pollination Services in Georgia

The production of many crops depends on biotic pollination. As pollinator populations decline, assessments of the potential consequential loss of economic value are critical. We estimate the economic value of pollination services ($608 million), crop vulnerability ratio (21 percent), and pollination’s contribution to agricultural production value (5 percent) for Georgia.Pollination, Colony Collapse Disorder, Georgia, Bioeconomic, Value, Vulnerability, Ecosystem Services, Crops, Honeybees, Pollinators, Pollination Dependency, Environmental Economics and Policy,

Socioeconomic status and neural processing of a go/no-go task in preschoolers: an assessment of the P3b

While it is well established that lower socioeconomic status (SES) is associated with poorer executive functioning (EF), how SES relates to the neural processing of EF in childhood remains largely unexplored. We examined how household income and parent education related to amplitudes of the P3b, an event-related potential component, during one EF task. We assessed the P3b, indexing inhibition and attention allocation processes, given the importance of these skills for academic success. Children aged 4.5-5.5 years completed a go/no-task, which assesses inhibitory control and attention, while recording EEG. The P3b was assessed for both go trials (indexing sustained attention) and no-go trials (indexing inhibition processes). Higher household income was related to larger P3b amplitudes on both go and no-go trials. This was a highly educated sample, thus results indicate that P3b amplitudes are sensitive to household income even within the context of high parental education. Findings build on the behavioral literature and demonstrate that SES also has implications for the neural mechanisms underlying inhibition and attention processing in early childhood.Published versio

Towards a Theology for Competitive Sport

Current research such as that of Sagar and Stoeber (2009) confirms how common amongst perfectionist sportspersons is the fear of failure with its attendant sense of worthlessness and shame (Sagar, Boardely & Kavussanu, 2011). In the face of this bleak reality, many see holy play as the only credible Christian alternative. In this paper, however, I disagree. After taking a fresh look at the roots of holy play as well as the contemporary magisterial work of Shirl Hoffman, I will argue for a more nuanced theological appreciation of sports competition

Reducing Adverse Impact While Maintaining Validity: Finding the Balance Between Competing Employee Selection Goals

Adverse (or disparate) impact has probably represented one of the most persistent and pervasive problems in employee selection. Innumerable approaches to eliminating its presence have been attempted, but most have been met with limited success. To date, this success has been measured in only slight reductions in adverse impact unless substantial losses in validity are accepted. While a number of reasons for these results have been advanced, this research asserted that part of the problem originated in the narrow perspective with which employee selection is often defined. This narrow perspective has resulted in a singular focus on validity with insufficient attention allocated to multiple criteria. The purpose of the present research was to expand upon an earlier study (Henderson & Ladd, 2001) that introduced a methodology (constrained estimation) that incorporated multiple objectives into the decision-making process associated with employee selection. Specifically, the goals of the methodology included reducing adverse impact while maintaining validity. In order to test the efficacy of this methodology, constrained estimation was applied to both Monte Carlo data as well as archival data obtained from an assessment project conducted from 1992 to 1993. It was also compared to two commonly used predictor weighting methodologies – Ordinary Least Squares regression and Unit Weighting. Results suggested that constrained estimation was moderately successful in reducing, but not eliminating, adverse impact while maintaining validity. Implications, limitations, and suggestions for future research are discussed

The Social and Environmental Effects of the Palm-Oil Industry in the Oriente of Ecuador

The development of large plantations of African oil palms in Ecuador\u27s Amazonian province of Napo has recently become a sensitive issue for this small South American country. Over the past few years, the indigenous peoples of the Cofan, Siona-Secoya, and Quichua tribes have felt increasingly threatened by the incursions of oil-palm plantations and very concerned about plans for a major expansion of this agro-industry in the region. Such an expansion could result in extensive destruction of the rain forest and a decline in the quality of the river waters, both vital to the physical and cultural survival of these indigenous tribes. The Ecuadorian government supports the expansion of these plantations as a key part of its development program in the Amazonian region and, for the most part, has been far less concerned about the needs of the Indians