The role of mental fatigue in soccer: a systematic review

Because of the role of mental fatigue in the development of elite soccer players, it has been a topic of interest for researchers in the last decades. First, we aim to shed light on the literature published about mental fatigue in soccer in the last 10 years. Second, based on the results obtained, we propose a new perspective on the role of cognitive effort in soccer. A systematic review (SR) was conducted following the PRISMA guidelines and registered in PROSPERO. A total of 18 articles met the inclusion criteria. The results showed an increase in the publications related to mental fatigue from 2014 onward. They were compared according to focus, sample, instruments and outcomes. Our proposal assumes that physical-physiological, technical-motor and tactical-cognitive demands entail a cognitive load that reduces the performance of players. Studies that prioritise controlling behavioural and physiological responses in cognitive tests are still needed.

A Systematic Review of Research Syntheses for Students with Mathematics Learning Disabilities and Difficulties

The purpose of this document is to provide readers with the coding protocol that authors used to code 36 research syntheses (including meta-analyses, evidence-based reviews, and quantitative systematic reviews) focused on mathematics interventions for students with learning disabilities (LD), mathematics learning disabilities (MLD), and mathematics difficulties (MD). The purpose of the systematic review of mathematics intervention syntheses was to identify patterns and gaps in content areas, instructional strategies, effect sizes, and definitions of LD, MLD, and MD. We searched the literature for research syntheses published between 2000 and 2020 and used rigorous inclusion criteria in our literature review process. We evaluated 36 syntheses that included 836 studies with 32,495 participants. We coded each synthesis for variables across seven categories including: publication codes (authors, year, journal), inclusion and exclusion criteria, content area focus, instructional strategy focus, sample size, methodological information, and results. The mean interrater reliability across all codes using this coding protocol was 90.3%. Although each synthesis stated a focus on LD, MLD, or MD, very few students with LD or MLD were included, and authors’ operational definitions of disability and risk varied. Syntheses predominantly focused on word problem solving, fractions, computer- assisted learning, and schema-based instruction. Syntheses reported wide variation in effectiveness, content areas, and instructional strategies. Finally, our results indicate the majority of syntheses report achievement outcomes, but very few syntheses report on other outcomes (e.g., social validity, strategy use). We discuss how the results of this comprehensive review can guide researchers in expanding the knowledge base on mathematics interventions. The systematic review that results from this coding process is accepted for publication and in press at Learning Disabilities Research and Practice.

Preferential treatment from the defense industry for the military

Purpose The military of today depends on the availability and readiness of high-technology weapon systems. As the military often has to focus on core tasks (the usage of systems), logistics and support tasks are outsourced to industry, which means that industrial suppliers gain importance for making weapon systems available and mission ready. However, companies are profit-maximizing and invest their best resources in the most promising business areas, which might be clients other than the (domestic) military customer. This raises the question of how the military can ensure that the defense industry provides the best performance: preferential treatment for the military. The purpose of this study is to investigate preferential treatment in the specific context of defense. Design/methodology/approach This paper reports on the examination of factors influencing preferential treatment for the military. The analysis uses structural equation modeling and data from a sample of German defense suppliers. Findings The results show that the perceived customer attractiveness has a strong effect on preferential customer treatment. Attractiveness is influenced by trust, commitment and a comparison with other customers. Research limitations/implications There are several implications for defense theory and practice, including the need for further consideration of relational in contrast to transactional practices in military–industrial supply collaboration, as these seem highly relevant for getting the best resources for producing and maintaining weapon systems. In addition, increasing customer attractiveness, in particular if the military lacks a domestic defense industry base, is proposed. Originality/value The findings are based on a focus sample of only defense suppliers. This paper transfers the industrial discussion about the buyer–supplier relationships and preferential customer treatment to the defense logistics research context.

Probe reconstruction for holographic X-ray imaging

In X-ray holographic near-field imaging the resolution and image quality depend sensitively on the beam. Artifacts are often encountered due to the strong focusing required to reach high resolution. Here, two schemes for reconstructing the complex-valued and extended wavefront of X-ray nano-probes, primarily in the planes relevant for imaging (i.e. focus, sample and detection plane), are presented and compared. Firstly, near-field ptychography is used, based on scanning a test pattern laterally as well as longitudinally along the optical axis. Secondly, any test pattern is dispensed of and the wavefront reconstructed only from data recorded for different longitudinal translations of the detector. For this purpose, an optimized multi-plane projection algorithm is presented, which can cope with the numerically very challenging setting of a divergent wavefront emanating from a hard X-ray nanoprobe. The results of both schemes are in very good agreement. The probe retrieval can be used as a tool for optics alignment, in particular at X-ray nanoprobe beamlines. Combining probe retrieval and object reconstruction is also shown to improve the image quality of holographic near-field imaging.

Effortful control as predictor of adolescents' psychological and physiological responses to a social stress test: The Tracking Adolescents' Individual Lives Survey

Effortful control is thought to foster adaptive action in defensive contexts and may thereby protect individuals against anxious inhibition and focus on their own distress. We examined if effortful control predicted adolescents' perceived arousal, unpleasantness, and control as well as autonomic (heart rate [HR]) and hypothalamic–pituitary–adrenal axis (cortisol) responses during social stress. The data came from a focus sample of the Tracking Adolescents' Individual Lives Survey, a prospective population study of Dutch adolescents (N = 715, 50.9% girls; mean age = 16.11, SD = 0.59), who participated in a laboratory session including a social stress task (public speaking and mental arithmetic). Perceived and physiological stress measures were assessed before, during, and after the social stress task. Effortful control was measured using various questionnaires and informants, as well as by means of a reaction time (RT) task assessing response inhibition. Overall, adolescents with high questionnaire-based effortful control tended to feel more relaxed, pleasant, and in control during the laboratory session than adolescents with lower levels of control and had stronger HR responses to the stress test. Adolescent girls with high inhibitory control as measured by the RT task also had strong HR responses, but inhibitory control was associated with high rather than low perceived arousal. Our results suggest that both questionnaire and RT measures of effortful control predict strong HR responses to challenging situations, but associational patterns diverge with regard to perceived stress measures.

Predetermined Sequences and a Direct Measure of Memory in a Concept-Identification Task

Predetermined sequences of stimuli and a direct measuring technique were used to estimate the specific hypotheses Ss used to solve concept-identification problems. Results indicate that Ss did not choose hypotheses at random and that the focus sample of most Ss contained those hypotheses which were consistent with reinforcement on previous trials. A comparison was also made between predictions of the Trabasso and Bower (1968) and Chumbley (1969) models concerning Ss' sampling behavior after error trials. Ss eliminated irrelevant hypotheses on both error and correct choice trials at about the same rate, supporting the predictions of the Chumbley (1969) model.