Irwinmangum5755

Objective Skilled motor praxis and speech production display marked asymmetries at the individual and the population level, favoring the right hand and the left hemisphere, respectively. Theories suggesting a common processing mechanism between praxis and speech are supported by evidence that shared neural architecture underlies both functions. Despite advances in understanding the neurobiology of this left-hemisphere specialization the cortical networks linking these 2 functions are rarely investigated on a behavioral level. Method This study deploys functional transcranial doppler (fTCD) ultrasound to directly measure hemispheric activation during skilled manual praxis tasks shown to be correlated to hemispheric speech lateralization indices. In a new paradigm we test the hypothesis that praxis tasks are highly dependent on the left hemisphere's capacity for processing sequential information will be better correlated with direction and strength of hemispheric speech lateralization. Results Across 2 experiments we first show that only certain praxis tasks (pegboard and coin-rotation) correlated with direct measurements of speech lateralization despite shared properties across all tasks tested. Second, through novel imaging of hemispheric activation during praxis, results showed that the pegboard differed in the lateralization pattern created and furthermore that it was significantly related to speech laterality indices, which was not the case for either of the other two tasks. Conclusion These results are discussed in terms of a lateralized speech-praxis control mechanism and demonstrates that measurements of motor paradigms through the use of fTCD are reliable enough to provide a new insight to the behavioral relationship been speech and handedness. (PsycInfo Database Record (c) 2021 APA, all rights reserved).School alienation is a complex phenomenon that has recently attracted considerable attention from psychologists because of the negative consequences that may result from it, such as poor academic performance, learning difficulties, school disengagement, behavioral problems, and withdrawal from the educational system, which interfere with students' well-being and academic achievement. However, the behaviors engaged in (i.e., mastery or helplessness) by students who experience feelings of school alienation and the associated impact on their academic performance have been overlooked in research. For this reason, the aim of this study was to investigate the roles played by mastery orientation and learned helplessness in the relationship between school alienation and academic achievement. The study sample consisted of 1,316 Italian students, 504 male (38.3%) and 812 female (61.7%). All participants ranged from age 13 to 20 years, with an average age of 16.27 (SD = 1.45). The results highlighted the roles of mastery orientation and learned helplessness in the relationship between students' perceptions of school alienation and academic achievement. The findings contribute to the literature on school alienation, highlighting the potential implications for schools. (PsycInfo Database Record (c) 2021 APA, all rights reserved).In linear optics, the angular momentum of light can be easily manipulated through the optical spin-orbit interaction (SOI) in structured media such as liquid crystals, metasurfaces, and forked gratings. 4EGI-1 Similarly, metasurfaces can be used to generate nonlinear optical beams with both custom-defined spin angular momentum (SAM) and orbital angular momentum (OAM) states. However, it has been limited to a low-order process in which only a Gaussian-shaped fundamental wave is used. In this work, the high-order nonlinear optical SOI effect on metasurfaces is demonstrated through the generation of multiple angular momentum states in nonlinear waves. This is achieved by exploiting the degrees of freedom provided by both the SAM and the OAM states of the fundamental wave (FW) and the topological charges of the plasmonic metasurfaces. The mechanism of both intrinsic and extrinsic contributions to the OAM of the nonlinear waves is revealed. High-order nonlinear SOI on metasurfaces offers new opportunities for realizing ultracompact nonlinear vortex beams.The first total syntheses of (±)-melicolones A and B, which have a unique and densely functionalized framework derived from a rearranged prenylated acetophenone, were accomplished in 12.3% combined overall yield. The concise and divergent synthesis of these two natural products, which were isolated in racemic form, was achieved in a longest linear sequence requiring only 9 steps (11 total steps) and 8 isolated intermediates using commercially available starting materials. This approach, which might enable access to all tetracyclic melicolones, features the highly regioselective (161) and diastereoselective (151) dipolar cycloaddition of a carbonyl ylide generated by the unusual cyclization of a rhodium carbene with the carbonyl oxygen atom of an aliphatic aldehyde. This cycloaddition proceeds with dominant steric control to give a highly functionalized oxabicycloheptane core. Stereoselective enolate alkylation led to a prenylated intermediate that underwent an intramolecular aldol reaction to give the penultimate tricyclic intermediate. Tandem epoxidation of the pendant prenyl group followed by a regioselective, acid-catalyzed cyclization delivered (±)-melicolones A and B.While single-molecule (SM) methods have provided new insights to various catalytic processes, bimolecular reactions have been particularly challenging to study. Here, the fluorogenic Knoevenagel condensation of an aromatic aldehyde with methyl cyanoacetate promoted by surface-immobilized piperazine is quantitatively characterized using super-resolution fluorescence imaging and stochastic analysis using hidden Markov modeling (HMM). Notably, the SM results suggest that the reaction follows the iminium intermediate pathway before the formation of a fluorescent product with intramolecular charge-transfer character. Moreover, the overall process is limited by the turnover rate of the catalyst, which is involved in multiple steps along the reaction coordinate.