Observed Quality of Formative Peer and Self-Assessment in Everyday Mathematics Teaching and its Effects on Student Performance

<p style="text-align: justify;">The positive effect of peer assessment and self-assessment strategies on learners' performance has been widely confirmed in experimental or quasi-experimental studies. However, whether peer and self-assessment within everyday mathematics teaching affect student learning and achievement, has rarely been studied. This study aimed to determine with what quality peer and self-assessment occur in everyday mathematics instruction and whether and which students benefit from it in terms of achievement and the learning process. Two lessons on division were video-recorded and rated to determine the quality of peer and self-assessment. Six hundred thirty-four students of fourth-grade primary school classes in German-speaking Switzerland participated in the study and completed a performance test on division. Multilevel analyses showed no general effect of the quality of peer or self-assessment on performance. However, high-quality self-assessment was beneficial for lower-performing students, who used a larger repertoire of calculation strategies, which helped them perform better. In conclusion, peer and self-assessment in real-life settings only have a small effect on the student performance in this Swiss study.</p>

Shape memory polymer foam: active deformation, simulation and validation of space environment

Shape memory polymer foam (SMPF) is being studied extensively as potential aerospace materials as they have high compression ratio, high specific strength and high specific modulus compared to other shape memory polymers. In this paper, a composite foam with shape memory epoxy (SMEP) as matrix and polyurethane (PU) as functional phase was prepared. The SMPF has been characterized by different analytical and testing methods, and its chemical crosslinking reaction and material properties have been studied. The SMPF was installed in the shape memory polymer composite (SMPC) flexible solar array system (SMPC-FSAS), and ground environment tests and orbital validation were performed. Considering the particularity of space environment, the thermal performance test of ground space environment can effectively test the reliability of shape memory performance. Finally, the SMPC-FSAS carried on SJ-20 satellite successfully deployed on geosynchronous orbit for the first time in the world. Moving forward, SMPF assesses the feasibility of applications in the space field and provides more valuable information.

An experimental performance comparison of Newtonian and non-Newtonian fluids on a centrifugal blood pump

The use of substitute fluid with similar rheological properties instead of blood is important due to ethical concerns and high blood volume consumption in pump performance test before clinical applications. The performance of a centrifugal blood pump with hydrodynamic journal bearing is experimentally tested using Newtonian 40% aqueous glycerin solution (GS) and non-Newtonian aqueous xanthan gum solution of 600 ppm (XGS) as working fluids. Experiments are performed at four different rotational speeds which are 2700, 3000, 3300, and 3600 rpm; experiments using GS reach between 8.5% and 37.2% higher head curve than experiments using the XGS for every rotational speed. It was observed that as the rotational speed and flow rate increase, the head curve difference between GS and XGS decreases. This result can be attributed to the friction reduction effect when using XGS in experiments at high rotation speed and high flow rate. Moreover, due to different fluid viscosities, differences in hydraulic efficiency were observed for both fluids. This study reveals that the use of Newtonian fluids as working fluids is not sufficient to determine the actual performance of a blood pump, and the performance effects of non-Newtonian fluids are remarkably important in pump performance optimizations.

Physiological and Performance Correlates of Squash Physical Performance

The physiological and performance attributes of elite squash players were investigated. Thirty-one players (21 males, world ranking [WR] 42-594; 10 females, WR 7-182) completed a battery of fitness tests which included an aerobic squash-specific physical performance test (SPPT), repeated-sprint ability (RSA), change-of-direction speed (COD), acceleration (5-m sprint), body composition and force development (countermovement jump) assessments. The SPPT provided a finishing lap score, V̇O2max, average movement economy and the lap corresponding to a blood lactate concentration of 4 mM.L-1. Players were ranked and assigned to HIGH or LOW performance tiers. Two-way ANOVA (performance level*sex) revealed higher ranked players performed better (p < 0.05) for SPPT final lap (d = 0.35), 4 mM.L-1 lap (d = 0.52) and COD (d = 0.60). SPPT displayed a ‘very-large’ correlation with 4 mM.L-1 lap (r = 0.86), ‘large’ correlations with COD (r = 0.79), RSA (r = 0.79), sum-of-7 skinfolds (r = 0.71) and V̇O2max (r = 0.69), and a ‘trivial’ correlation with average movement economy (r = 0.02). Assessments of cardiovascular fitness (i.e. 4 mM.L-1 lap), RSA, COD and body composition appear highly pertinent for performance profiling of squash players. Regular, submaximal assessment of the 4 mM.L-1 lap during the SPPT may offer a practical athlete monitoring approach for elite squash players.

A study on Predictive Modeling of Users’ Parasocial Relationship Types based on Social Media Text Big Data

The traditional quasi-social relationship type prediction model obtains prediction results by analyzing and clustering the direct data. The prediction results are easily disturbed by noisy data, and the problems of low processing efficiency and accuracy of the traditional prediction model gradually appear as the amount of user data increases. To address the above problems, the research constructs a prediction model of user quasi-social relationship type based on social media text big data. After pre-processing the collected social media text big data, the interference data that affect the accuracy of non-model prediction are removed. The interaction information in the text data is mined based on the principle of similarity calculation, and semantic analysis and sentiment annotation are performed on the information content. On the basis of BP neural network, we construct a prediction model of user’s quasi-social relationship type. The performance test data of the model shows that the average prediction accuracy of the constructed model is 89.84%, and the model has low time complexity and higher processing efficiency, which is better than other traditional models.

Fourier spotting: a novel setup for single-color reflectometry

Single-color reflectrometry is a sensitive and robust detection method in optical biosensor applications, for example for bioanalysis. It is based on the interference of reflected monochromatic radiation and is label free. We present a novel setup for single-color reflectometry based on the patented technology of Berner et al. from 2016. Tilting areas of micro-mirrors allow us to encode the optical reflection signal of an analyte and reference channel into a particular carrier frequency with the amplitude being proportional to the local reflection. Therefore, a single photodiode is sufficient to collect the signals from both channels simultaneously. A 180∘ phase shift in the tilt frequency of two calibrated micro-mirror areas leads to a superposition of the analyte and reference signal which enables an efficient reduction of the baseline offset and potential baseline offset drift. A performance test reveals that we are able to detect changes of the refractive index n down to Δn < 0.01 of saline solutions as regents. A further test validates the detection of heterogeneous binding interaction. This test compromises immobilized testosterone-bovine serum albumin on a three-dimensional layer of biopolymer as ligand and monoclonal anti-testosterone antibodies as analyte. Antibody/antigen binding induces a local growth of the biolayer and change in the refractive index, which is measured via the local change of the reflection. Reproducible measurements enable for the analysis of the binding kinetics by determining the affinity constant KA = 1.59 × 10− 7 M− 1. In summary, this work shows that the concept of differential Fourier spotting as novel setup for single-color reflectometry is suitable for reliable bioanalysis.

Concrete with Partial Substitution of Waste Glass and Recycled Concrete Aggregate

The current practice of concrete is thought to be unsuitable because it consumes large amounts of cement, sand, and aggregate, which causes depletion of natural resources. In this study, a step towards sustainable concrete was made by utilizing recycled concrete aggregate (RCA) as a coarse aggregate. However, researchers show that RCA causes a decrease in the performance of concrete due to porous nature. In this study, waste glass (WG) was used as a filler material that filled the voids between RCA to offset its negative impact on concrete performance. The substitution ratio of WG was 10, 20, or 30% by weight of cement, and RCA was 20, 40, and 60% by weight of coarse aggregate. The slump cone test was used to assess the fresh property, while compressive, split tensile, and punching strength were used to assess the mechanical performance. Test results indicated that the workability of concrete decreased with substitution of WG and RCA while mechanical performance improved up to a certain limit and then decreased due to lack of workability. Furthermore, a statical tool response surface methodology was used to predict various strength properties and optimization of RCA and WG.

Reference centiles based on year-to-year changes for a longitudinal evaluation of motor performance in children and adolescents

Objectives The aim was to evaluate the longitudinal course of motor skills development in children with a view to improve the understanding of intra-individual variance. Previous publications have been based on cross-sectional data or analyzed longitudinal studies in a cross-sectional manner. Design Longitudinal. Year-to-year change. Methods The present study is based on motor function data collected in the LIFE Child study (Germany). The participants (6 to 17 years) completed parts of the motor tests according to the standard of the German Motor Performance Test 6–18 (DMT). For a total of 1653 participants, 4616 motor tests with an annual interval in the period 2011 to 2019 were included in the evaluation. Results We were able to produce gender and age-specific change centiles for the test items standing long jump, jumping sideways, push-ups, stand and reach and balancing walking backwards. Each set of centiles revealed a range of variability in motor development in children and adolescents, with distinct progressive patterns in the different test items and different genders. The supplied tables offer an indication of expected year-to-year change for each test item depending on age and gender. Depending on the test item and the mean age, a deterioration in test results after a one-year interval was observed, despite cross-sectional centiles showing an upward trend. Conclusion We present a user-friendly tool as a way to assess individual dynamic changes in motor development of children and adolescents. In combination with the well-known cross-sectional centiles as baseline, this can be helpful for the scientific evaluation of motor skills tests and can also be used in school settings.