The Effects of Self-Regulation,Motivation, Anxiety,and Attributions on Mathematics Achievement for Fifth and Sixth Grade Students

For this quantitative study, a total of n = 761 students (58.1% female) from selected fifth- and sixth-grade mathematics classrooms in Alabama were surveyed in order to investigate the relationships between self-regulated learning, motivation, anxiety, attributions and achievement in mathematics. Data analyses revealed that significant contributions are made by motivation and anxiety on both test score and mathematics grade for fifth grade students. Specific factors (e.g., self-efficacy, worry, other, and failure) were related to academic performance while failure attribution was significantly related to mathematics grade. As for sixth grade students, data analyses showed relationships exist between motivation, anxiety and academic performance with specific factors (i.e., self-efficacy, intrinsic value, and worry) significantly predicting both test score and mathematics grade for sixth graders. The findings underlie the importance of motivation and anxiety for students and how these constructs interact to facilitate self-regulation over the course of developing expertise in a domain, such as mathematics.     

Variation of optical basicity with probe ion,for Cs2O + B2O3 and Li2O + B2O3 glasses

Optical basicities (Γ) for Cs₂O + B₂O₃ and Li₂O + B₂O₃ glasses have been measured as a function of glass composition, using Tl⁺, Pb²⁺ and Bi³⁺ probe ions. The three probe ions register different values of Γ for glasses of given composition (and also for pure B₂O₃ glass and water). The divergence decreases as the alkali metal ion size decreases.For the Li₂O + B₂O₃ glasses, ideal (calculated) optical basicities agree within experimental precision with experimental values registered by Pb²⁺ (Γ_Pb²⁺) up to about 15 mol% Li₂O. For higher Li₂O contents, and for the Cs₂O + B₂O₃ glasses, ideal optical basicities agree less well with Γ_Pb²⁺, but show similar trends with composition to those shown by Γ_Pb²⁺.     

Order and Defects in Ceramic Semiconductor Nanoparticle Superstructures as a Function of Polydispersity and Aspect Ratio

The supreme aim of nanoparticle‐based materials is to achieve new properties extending over the features of individual constituents. The emergence of cooperativity necessitates precise positioning and orientation of nanoparticle ensembles. Thus, it is important to understand and learn how to control self‐assembly processes of nanoparticles. Besides shape, the structural uniformity plays a key role for ordering in superstructures. Therefore, it is challenging to synthesize nanorods with narrow polydispersity. An analysis of the systematic variation of aspect ratio and polydispersity is missing. A series of zinc oxide nanorods is presented and it is shown that their formation resembles step‐polymerization with an amorphous precursor state as a monomer and polar ZnO particles as entities capable of growing. The width of nanorods is kept constant (15 nm) and the length is varied between 20 and 100 nm, as well as improving the polydispersity of the nanorod length from 36% to 10%. Best samples have been achieved by post‐preparative treatment using gradient centrifugation. A method has been developed for semiquantitative evaluation of orientational order. Ordering in structures formed by quasispherical particles is always low despite low polydispersity. For rod‐like nanoparticles with increasing aspect ratio, superstructure order depends on the occurrence of different defects, which correlate differently to nanoparticle polydispersity.     

Binaural speech unmasking and localization in noise with bilateral cochlear implants using envelope and fine-timing based strategies

Four adult bilateral cochlear implant users, with good open-set sentence recognition, were tested with three different sound coding strategies for binaural speech unmasking and their ability to localize 100 and 500 Hz click trains in noise. Two of the strategies tested were envelope-based strategies that are clinically widely used. The third was a research strategy that additionally preserved fine-timing cues at low frequencies. Speech reception thresholds were determined in diotic noise for diotic and interaurally time-delayed speech using direct audio input to a bilateral research processor. Localization in noise was assessed in the free field. Overall results, for both speech and localization tests, were similar with all three strategies. None provided a binaural speech unmasking advantage due to the application of 700 micros interaural time delay to the speech signal, and localization results showed similar response patterns across strategies that were well accounted for by the use of broadband interaural level cues. The data from both experiments combined indicate that, in contrast to normal hearing, timing cues available from natural head-width delays do not offer binaural advantages with present methods of electrical stimulation, even when fine-timing cues are explicitly coded.     

Synthesis of Indomorphan Pseudo‐Natural Product Inhibitors of Glucose Transporters GLUT‐1 and ‐3

Bioactive compound design based on natural product (NP) structure may be limited because of partial coverage of NP‐like chemical space and biological target space. These limitations can be overcome by combining NP‐centered strategies with fragment‐based compound design through combination of NP‐derived fragments to afford structurally unprecedented “pseudo‐natural products” (pseudo‐NPs). The design, synthesis, and biological evaluation of a collection of indomorphan pseudo‐NPs that combine biosynthetically unrelated indole‐ and morphan‐alkaloid fragments are described. Indomorphane derivative Glupin was identified as a potent inhibitor of glucose uptake by selectively targeting and upregulating glucose transporters GLUT‐1 and GLUT‐3. Glupin suppresses glycolysis, reduces the levels of glucose‐derived metabolites, and attenuates the growth of various cancer cell lines. Our findings underscore the importance of dual GLUT‐1 and GLUT‐3 inhibition to efficiently suppress tumor cell growth and the cellular rescue mechanism, which counteracts glucose scarcity.     

Confocal scanning laser ophthalmoscopy improvement by use of Mueller-matrix polarimetry

A new technique for improving the signal-to-noise ratio and the contrast in images recorded with a confocal scanning laser system is presented. The method is based on the incorporation of a polarimeter into the setup. After the spatially resolved Mueller matrix of a sample was calculated, images for incident light with different states of polarization were reconstructed, and both the best and the worst images were computed. In both the microscope and the opthalmoscope modes, the best images are better than the originals. In contrast, the worst images are poorer. This technique may be useful in different fields such as confocal microscopy and retinal imaging.     

Strain‐Accelerated Formation of Chiral,Optically Active Buta‐1,3‐dienes

The formal [2+2] cycloaddition–retroelectrocyclization (CA–RE) reactions between tetracyanoethylene (TCNE) and strained, electron‐rich dibenzo‐fused cyclooctynes were studied. The effect of ring strain on the reaction kinetics was quantified, revealing that the rates of cycloaddition using strained, cyclic alkynes are up to 5500 times greater at 298 K than those of reactions using unstrained alkynes. Cyclobutene reaction intermediates, as well as buta‐1,3‐diene products, were isolated and their structures were studied crystallographically. Isolation of a rare example of a chiral buta‐1,3‐diene that is optically active and configurationally stable at room temperature is reported. Computational studies on the enantiomerization pathway of the buta‐1,3‐diene products showed that the eight‐membered ring inverts via a boat conformer in a ring‐flip mechanism. In agreement with computed values, experimentally measured activation barriers of racemization in these compounds were found to be up to 26 kcal mol^?1.