Sexual dimorphism in bite performance drives morphological variation in chameleons

Phenotypic performance in different environments is central to understanding the evolutionary and ecological processes that drive adaptive divergence and, ultimately, speciation. Because habitat structure can affect an animal's foraging behaviour, anti-predator defences, and communication behaviour, it can influence both natural and sexual selection pressures. These selective pressures, in turn, act upon morphological traits to maximize an animal's performance. For performance traits involved in both social and ecological activities, such as bite force, natural and sexual selection often interact in complex ways, providing an opportunity to understand the adaptive significance of morphological variation with respect to habitat. Dwarf chameleons within the Bradypodion melanocephalum-Bradypodion thamnobates species complex have multiple phenotypic forms, each with a specific head morphology that could reflect its use of either open-or closed-canopy habitats. To determine whether these morphological differences represent adaptations to their habitats, we tested for differences in both absolute and relative bite performance. Only absolute differences were found between forms, with the closed-canopy forms biting harder than their open-canopy counterparts. In contrast, sexual dimorphism was found for both absolute and relative bite force, but the relative differences were limited to the closed-canopy forms. These results indicate that both natural and sexual selection are acting within both habitat types, but to varying degrees. Sexual selection seems to be the predominant force within the closed-canopy habitats, which are more protected from aerial predators, enabling chameleons to invest more in ornamentation for communication. In contrast, natural selection is likely to be the predominant force in the open-canopy habitats, inhibiting the development of conspicuous secondary sexual characteristics and, ultimately, enforcing their overall diminutive body size and constraining performance

The Nexus of Passive-Avoidant Leadership and Deviancy: Exploring Job Embeddedness

In the aftermath of the COVID-19 pandemic, employers have experienced unprecedented changes in the workforce, including labor shortages and new legislation. As a result, many organizations, known as second-chance employers, proactively seek alternative talent sources to mitigate staffing shortages, including hiring candidates with criminal backgrounds, either voluntarily or as mandated by law. However, this approach has challenges; individuals with criminal records often lack essential support upon reentry and experience an increased risk of reoffending. Although existing literature indicates that the appropriate leadership style is crucial for behavior correction, there is a gap in the literature addressing employees who work for a second-chance employer. Additionally, research on job embeddedness and workplace deviance presents mixed results. This study addressed the gap in the existing literature by examining the relationship among passive-avoidant leadership, job embeddedness, and deviant workplace behaviors. Study limitations include potential social desirability bias, limited generalizability due to the focused context, and a cross-sectional design preventing causal conclusions. This study featured 217 participants recruited from a convenient sample of 16,186 LinkedIn contacts. Subjects completed the multifactor leadership questionnaire, the deviant behavior scale, and the global measure of job embeddedness scale. Findings indicate that job embeddedness does not moderate the relationship between passive-avoidant leadership and deviant workplace behaviors, but passive-avoidant leadership positively and significantly relates to deviant workplace behaviors. Additionally, there was no relationship found between job embeddedness and deviant workplace behaviors. This research has implications for leadership, organizational behavior, the Christian community, and human resources management, stressing the relationship between leadership and deviant workplace behaviors

On Planar Greedy Drawings of 3-Connected Planar Graphs

A graph drawing is greedy if, for every ordered pair of vertices (x,y), there is a path from x to y such that the Euclidean distance to y decreases monotonically at every vertex of the path. Greedy drawings support a simple geometric routing scheme, in which any node that has to send a packet to a destination "greedily" forwards the packet to any neighbor that is closer to the destination than itself, according to the Euclidean distance in the drawing. In a greedy drawing such a neighbor always exists and hence this routing scheme is guaranteed to succeed. In 2004 Papadimitriou and Ratajczak stated two conjectures related to greedy drawings. The greedy embedding conjecture states that every 3-connected planar graph admits a greedy drawing. The convex greedy embedding conjecture asserts that every 3-connected planar graph admits a planar greedy drawing in which the faces are delimited by convex polygons. In 2008 the greedy embedding conjecture was settled in the positive by Leighton and Moitra. In this paper we prove that every 3-connected planar graph admits a planar greedy drawing. Apart from being a strengthening of Leighton and Moitra\u27s result, this theorem constitutes a natural intermediate step towards a proof of the convex greedy embedding conjecture

Elasto-Plastic Analysis of Bonded Joints with Macro-Elements

The Finite Element (FE) method could be able to address the stress analysis of bonded joints. Nevertheless, analyses based on FE models are mainly computationally cost expensive and it would be profitable to develop simplified approaches, enabling extensive parametric studies. Firstly, a 1D-bar and 1D-beam simplified models for the bonded joint stress analysis, assuming a linear elastic adhesive material, are presented. These models derive from an approach, inspired by the finite element (FE) method using a formulation based on a 4-node macro-element, which is able to simulate an entire bonded overlap. Moreover, a linear shear stress variation in the adherend thickness is included in the formulation. Secondly, a numerical procedure is then presented to introduce into both models an elasto-plastic adhesive material behavior, while keeping the previous linear elastic formulation. Finally, assuming an elastic perfectly plastic adhesive material behavior, the results produced by simplified models are compared with the results predicted by FE using 1D-bar, plane stress and 3D models. Good agreements are shown

Crosswell seismic tomographic inversion using NSGA II

In the present paper, the solution of the seismic data inversion problem through multi-objective optimization with NSGA II is addressed. The seismic inversion consists of estimating the slowness of rocks in the subsurface from the travel times of the waves through the transmitters and receivers of the seismic waves. The inversion process uses the multi-objective optimization technique, in which it is necessary to estimate the trade-off between the misfit functional and the stabilizing constraint. The constraint used was the classic first-order Tikhonov. A synthetic model of inclined layers was chosen. The results obtained were acceptable. Based on the graph of the cumulative errors related to the solution, it was estimated correctly, that is, the optimization method used was effective to obtain acceptable results, in addition to the constraint solving the instability problem of the inverse problem treated. Another important result was the achievement of a convergence curve on the Pareto frontier, an important result for future research.Comment: 14 pages, 12 figure

Simplified stress analysis of hybrid (bolted/bonded) joints

The load transfer in hybrid (bolted/bonded) – denoted HBB – single-lap joints is complicated due to the association of two different transfer modes (discrete and continuous) through elements with different stiffnesses. The Finite Element (FE) method can be used to address the stress analysis of those joints. However, analyses based on FE models are computationally expensive and it would be profitable to use simplified approaches enabling extensive parametric studies. Two among the authors of this paper participated in the development of a dedicated 1D-beam approach (Paroissien 2007). This paper presents an extension of this framework enabling (i) the analysis of HBB joints made of dissimilar laminated or monolithic adherends, and (ii) the introduction of non linear material behaviour for both the adhesive layer and the fasteners. The output data are the distributions of displacements and forces in the adherends and fasteners, as well as those of adhesive shear and peeling stresses, allowing for a fast assessment of the material behaviour and strength prediction of HBB joints. The use of this model is illustrated in the identification of the failure mechanisms of HBB joints under quasistatic loadings, based on experimental and numerical tests on single-lap HBB joint. It is worth mentioning that the model can support pure bonded and pure bolted configurations. It can be used during the presizing phase at the design office (possibly independently on commercial software), to obtain quickly mechanical performances and to help in decision making. Moreover, it was shown that the judicious choice of the adhesive material allows for a significant increase of the static and fatigue strength compared to pure bolted or bonded corresponding configurations (Kelly 2006) (Paroissien 2006). The model can then be used to formulate at best adhesive materials to optimize the mechanical performance of HBB joints according to work specifications

Ischemic preconditioning and acute recovery of performance in rugby union players

Ischemic preconditioning has been used as a training and/or pre-competition strategy; however its use for post-exercise recovery is still unclear. This study aimed to evaluate the impact of ischemic preconditioning on performance and recovery ratings following a simulated match in sub-elite rugby players. Following baseline measures, male players (n = 8) performed a 40 min, rugby-specific exercise protocol followed by an intervention: 21 min of ischemic preconditioning (3 × 5 min occlusion at 220 mmHg with 2 min reperfusion at 0 mmHg) or passive rest (control) on 2 separate days. An agility T-test, a single vertical countermovement jump and 30 s of continuous vertical jumps were performed at baseline (–24 h), immediately after exercise, and immediately after the intervention. The rugby-specific exercise protocol induced similar mean heartrates (158.3 ± 18.0 vs. 158.7 ± 16.0 bpm) and perceived exertion levels (8.2 ± 0.9 vs. 8.0 ± 1.0) for both trials with all recovery performance measures and rating of recovery (13.9 ± 1.4 vs. 13.6 ± 1.6) similar between ischemic preconditioning and control trials (best p = 0.385). We conclude that the use of ischemic preconditioning does not improve recovery acutely (~1 h) including specific variables related to rugby performance in amateur rugby union players