Protective effect of aerobic fitness on the detrimental influence of exhaustive exercise on information processing capacity

Although aerobic fitness has been thought to protect against the detrimental cognitive effects following exhaustive exercise, available evidence from studies using traditional mean behavioral measures remain somewhat equivocal.PurposeThis study aimed to reconcile this discrepancy by using a novel theory-driven diagnostic tool, the Systems Factorial Technology (SFT).MethodsSixty-six healthy young adults aged from 18 to 30 years old with different levels of aerobic fitness (n = 33 for the higher-fit and lower-fit groups) completed a go/nogo version of redundant-target task before and after a graded exercise test (GXT) until exhaustion. SFT was used to calculate the resilience capacity, which reflects the information processing capacity underlying inhibitory control.ResultsFollowing the GXT, both higher-fit and lower-fit groups showed faster responses while leaving accuracy unchanged as compared to the performance at the pretest. On the other hand, the resilience capacity decreased for the lower-fit group but was maintained for the higher-fit group.ConclusionThe present findings suggest that aerobic fitness may modulate the individual difference in decisional mechanism following exhaustive exercise. In sum, this study offers an alternative mechanistic explanation regarding cognitive individual differences in response to exhaustive exercise and provides novel insights into the significance of maintaining a state of high physical fitness for those who need to perform cognitively challenging tasks under physically stressful conditions (e.g., elite athletes).     

Site preference and alloying effect of Re atoms in the edge dislocation cores in Ni3Al

Using Cambridge sequential total energy package method based on the density functional theory, we investigated the site preference and alloying effect of Re atoms in the [1 0 0] (0 1 0) edge dislocation cores in Ni₃Al. Due to the introduction of a Re atom, the energetic and electronic structure of dislocation core systems have been changed a lot. The binding energy results suggest Re atom prefers Al site, especially the centre site in the centre-Al system, which can be explained by the results of Mulliken orbital population and density of states. When Re atom occupies the centre site in the centre-Al system, the DC system has the highest stability and stronger bonds formed between the Re atom and its nearest neighbouring atom due to hybridization of the Re-5d and Ni-3d orbitals.     

The perception of nested affordances: An examination of expert climbers

Nested affordances in climbing comprise of multiple sequential actions, encompassing more than isolated reaching and grasping. This study examined the extent to which the perception of (multiple) nested affordances in climbing can be understood relative to body-scaled anthropometrics (arm span) and action-scaled (maximal action capabilities) measures, in relation to sequential task-goals of varying complexity. The utilisation of functionally equivalent actions during the actualisation of nested affordances was also investigated. Participants were required to estimate the maximal distance a handhold could be reached in four conditions of varying complexity: nested affordances (reach to Touch; reach to Grasp) vs. multiple nested affordances (reach to grasp with one hand followed by Removing the other hand from the starting handhold; reach to grasp with one hand followed by Moving up to another handhold). Ten expert climbers first had to estimate their maximal reaching distance in these different conditions (Touch, Grasp, Remove, Move Up) before performing the climbing movement. This sequence of estimation-action was repeated four times in each condition. Results revealed that action-scaling measures better captured nested affordances when multiple sequential behaviours are nested than body-scaled measures. Our findings also suggest that expert climbers utilise functionally equivalent movements during the realisation of multiple nested affordances (Remove and Move Up conditions).     

Time-dependent adhesion of a polydimethylsiloxane (PDMS) elastomer film to a flat indenter tip characterized using a cohesive-zone law

The work of adhesion between a polydimethylsiloxane (PDMS) elastomer film and a flat diamond tip was measured by instrumented indentation. The results showed that the apparent work of adhesion between the tip and the PDMS film increases with increasing dwell time and retreating velocity; on the other hand, the indentation depth has no significant effect on adhesion. The indentation experiment was analysed with viscoelastic finite element simulations with rate-dependent cohesive elements, from which the time evolution of adhesion was quantitatively implemented into a rate-dependent cohesive-zone law.     

A new orthorhombic approximant of the icosahedral Al–Cu–Fe quasicrystal

We report on the formation of a new crystalline approximant phase of the icosahedral (i-)Al–Cu–Fe quasicrystal. This phase is formed during sintering of Al-based composites reinforced with i-AlCuFeB quasicrystalline particles. The structure of this phase has been characterized by transmission electron microscopy (TEM) and high-resolution electron microscopy (HREM). TEM revealed that it is a B-centred orthorhombic phase with lattice parameters a = 1.166 nm, b = 1.195 nm and c = 3.44 nm. Its chemical composition, as determined by electron energy loss spectroscopy (EELS), is close to Al_76.9Cu_2.7Fe_20.4, with an average number of valence electrons per atom e/a of 1.92, similar to the value in all other approximants of the i-phase discovered thus far. Initial results on local atomic arrangements along one of its pseudo-5-fold axes are also presented.     

Negative,zero and positive stiffness in extended Eshelby plates

Structures under loading can show positive and negative stiffness (during buckling) with zero stiffness just being one point of transition. Material structures with extended zero stiffness regimes have also been reported. Using the example of an extended Eshelby plate with a positive and negative edge dislocation, we show the existence of finite regimes of positive, zero and negative stiffness in a single system. Given that stable states/configurations of negative stiffness cannot exist in an isolated system; we show the existence of metastable states of negative stiffness along with unstable states of positive stiffness. The system also exhibits one point of unstable equilibrium.     

组块紧密性导致组块破解困难：部件类型还是交错关系？

本研究的目的是澄清“组块紧密性为何导致组块破解困难”。研究基于汉字减法任务,也即让被试从一个源汉字中移动一个目标部件从而得到一个新汉字,在三个实验中检验了部件类型和交错关系的作用。结果显示,交错条件比非交错条件解答率更低反应时更长;而部件类型效应则主要体现在非交错条件的反应时指标上。结果提示,组块紧密性导致了组块破解困难,这主要取决于空间交错关系;相对的,部件类型作用较小。     

Autoshaping with common and distinctive stimulus elements, compact and dispersed arrays

Four groups of pigeons were trained with a standard autoshaping procedure in which a brief fixed-duration interval always followed by a grain delivery alternated with a longer variable-duration interval never associated with grain delivery. One of two stimuli was always presented during each interval. One of them contained three black dots and a black star on a green background; the other contained four black dots on a green background. The four elements of each stimulus were arranged in a more compact array for two groups and in a more dispersed array for the other two groups. Which of the two stimuli preceded grain delivery was counterbalanced within each pair of groups. The speed of occurrence of the first autoshaped peck was not affected by whether the stimulus containing the distinctive star element preceded grain delivery, but autoshaping was faster when the stimulus arrays were compact than when they were dispersed. During 560 response-independent training trials that followed the first autoshaped peck, this pattern reversed; both discriminative control over responding and the relative frequency of pecking the stimulus that preceded grain delivery were greater for the two groups where this stimulus contained the discriminative element than for the two groups where it contained only common elements. During subsequent testing with stimuli containing only a single element each, the distinctive feature was responded to proportionately more often by the two groups for which it had been an element of the stimulus preceding grain delivery than by the two groups for which it had been an element of the stimulus complex that never was associated with grain delivery. These data add further support to the hypothesis that the initial occurrence of autoshaped responding and its subsequent maintenance are not affected by the same variables. They also suggest that automaintenance is as sensitive as response-dependent training to the presence or absence of a distinctive stimulus element among several common elements and that this sensitivity appears to be independent of the specific method used for presenting the stimuli during automaintenance.     

Orthographic congruency effects in the suprasegmental domain: Evidence from Thai

The influence of orthographic knowledge on lexical tone processing was examined by manipulating the congruency between the tone and the tone marker of Thai monosyllabic words presented in three metalinguistic tasks. In tone monitoring (Experiment 1) and same–different tone judgement (Experiment 2)—that is, tasks that require an explicit analysis of tone information—an orthographic congruency effect was observed: Better performance was found when both tone and tone marker led to the same response than when they led to opposite, competing responses. In rhyme judgement (Experiment 3), a metaphonological task that allows tone to be processed in a more natural way since it does not require explicit analysis of tone, the orthographic effect emerged only when the interstimulus interval was lengthened from 30 to 1,200 ms. In addition to demonstrating the generalization of the orthographic congruency effect to the suprasegmental domain in Thai, the present data also suggest relatively late and task-dependent activation of orthographic representations of tone.     

Newly observed microscopic planar defects on {111} in natural diamond

Abstract

Circular disc-crack-like defects randomly distributed on {111} planes have been discovered by 300kV transmission electron microscopy in diamond that had crystallized on non-faceted growth surfaces of mean orientation {100}. In a sample of ～ 100 defects, disc diameters were narrowly distributed about a mean of 1·2 μm and one in seven discs were located on a coplanar stacking fault of average diameter 2 μm. Discs totally enclosed within the specimen exhibit concentric moiré fringes covering their image areas when viewed obliquely, showing them to be dilated into thin lenticles. Internal pressures, deduced from moiré-fringe counts on six lenticles, were in the range 1·5 to 1·8 GPa.