Double-layer absorbers have recently been extensively studied because single-layer absorbers can hardly meet the requirements of advanced absorbing materials. However, determining how to couple the matching and absorption layers remains a challenge. In the present work, we applied the hydrothermal method to prepare an ultrasmall Fe3O4 nanoparticle and a hierarchical MXene/Fe3O4 composite and then studied the microwave attenuation capabilities of single- and double-layer absorbers containing these two materials with different thicknesses. Absorbers with well-coupled layers showed improved absorption performance on account of the excellent impedance matching behavior of the Fe3O4 layer and the high microwave attenuation capability of the MXene/Fe3O4 layer. When the thickness of the matching layer filled with Fe3O4 was 0.1 mm and that of the absorption layer filled with MXene/Fe3O4 was 1.9 mm, a maximum reflection loss of −48.7 dB was achieved at 9.9 GHz. More importantly, when the thicknesses of the matching and absorption layers were 0.9 and 1.1 mm, respectively, the effective bandwidth was nearly 3.9 GHz. The double-layer absorbers with enhanced absorption properties may be regarded as a new generation of materials for electromagnetic wave absorption.

In this paper, we report two experiments in Spanish designed to find out what kind of processes underlie the online parsing of complex noun phrases (NPs). To that end, we used a ‘click detection’ paradigm coupled with an oral comprehension task with sentences made up of complex NPs comprising embedded prepositional phrases PPs or coordinate NPs. The critical NPs consisted of words or pseudowords, and were inserted either at subject position (Experiment 1) or at object position (Experiment 2) in the sentence. Results show an opposite pattern of RTs to clicks when the complex NP is located at subject (vs. object) position, with the former case showing heavier processing demands as the parser delves deeper into the complex NP, regardless of the internal constituency of the target NP and its lexical content, and the latter yielding the opposite pattern. These results suggest that structural complexity by itself does not determine an increase in processing costs during sentence parsing, which is only apparent in cases involving deferred operations like subject-verb agreement.

The Mirror System Hypothesis of Michael Arbib (2012), with respect to the cultural evolutionary origins of syntactic structure, allows to make a set of predictions about the neural mechanisms that govern the processing of modern human languages. Neuroimaging techniques may be employed to test these predictions and inform an evolutionary theory of language syntax. In this commentary, I will argue that future neuroimaging research needs in particular to: i) clarify whether linear sequential versus non-linear hierarchical structure differentially depend on mirror neurons as opposed to higher-order heteromodal cortices; ii) challenge current neuroscientific evidence on multilingualism: as it stands, syntactic processing appears to be mediated by the same neural mechanisms across languages, independently of cross-linguistic idiosyncrasies; iii) devise longitudinal studies of grammar acquisition in newborns and children; iv) recreate in the laboratory nearly-ecological conditions for the emergence of syntactic constructions through cultural and social interaction, and exploit the “experiment of nature” of pidgin and creole languages.

The book describes three elementary units of action – the reflex, the oscillator, and the servomechanism – and the principles by which they are combined to make complex units. The combining of elementary units to make complex units gives behavior and the neural circuitry underlying behavior a hierarchical structure. Circuits at higher levels govern the operation of lower circuits by selective potentiation and depotentiation: by regulating the potential for operation in lower circuits – raising the potential for some and lowering it for others – a higher unit establishes the overall pattern to be exhibited in the combined operations of the lower units, while leaving it to the lower units to determine the details of the implementation of this pattern. A theory of motivation of the kind long championed by ethologists and physiological psychologists grows out of the notion of the selective potentiation and depotentiation of hierarchically structured units of behavior. The question then becomes how this conception of motivation may be integrated with a conception of a learned representation of the world to yield a theory of how animals produce novel motivated behavioral sequences based on learned representations. The representation of space, which is central to the behavior of organisms at least as lowly as the digger wasp, is a promising domain for the investigation of this question. Another promising area is the representation of skilled movements, such as handwriting. A number of issues in cognitive and developmental psychology are illumined by this theory about the organization of action. Among these are the degrees-of-freedom problem, the role of practice in development and in the learning of skilled action, and the role of mental rotation of spatial representations.