Hyperactive and hypoxic children: Signal detection, sustained attention, and behavior.

Two parameters from signal detection theory—perceptual sensitivity and decision criterion cutoff scores—were used in the analysis of vigilance performance of 30 hyperactive (mean age 8.5 yrs), 30 hypoxic (mean age 9 yrs), and 47 normal (mean age 8.8 yrs) children. Signal detection analyses of 3 Continuous Performance Test conditions indicated that with increasing age, Ss obtained significantly more hits, fewer false alarms, higher perceptual sensitivity, and responded with greater caution. Overall deficits in signal discrimination (perceptual sensitivity level) were obtained for both the hyperactive and hypoxic Ss when compared to normal age-mates. Whereas the hypoxic Ss demonstrated additional decrements in sustaining attention (sensitivity decrement over time), the hyperactive Ss were impaired by low-response caution, reflecting difficulty inhibiting impulsive responses. Possible differences in hyperactive sample characteristics across studies and time-related recovery factors following hypoxia are discussed. (43 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Porous Metal Sheets of NiTi made by Wet Powder Spraying

As a promising method to produce thin porous NiTi sheets, Wet Powder Spraying (WPS) is applied for NiTi powders. Layers with a thickness of 150 μm are obtained from pre‐alloyed NiTi powders with a particle size of < 12 μm. Optimized process control for spraying and sintering was used. Microstructure and phase formation is characterized. The sheets with a porosity of 15 % show a high pseudoelastic flexibility at room temperature. Phase transformation temperatures are determined by Differential scanning calorimetry (DSC). The one way effect could be demonstrated.     

Investigating the relationship between success factors and student participation in online and blended learning in adult education

Online and blended learning (OBL) is valued, but it also offers challenges. Literature indicates that OBL can enhance access to education and increase flexibility for students. However, the reported dropout rates indicate that student participation in OBL programmes is a concern. Scientifically valid knowledge about how factors that help students participate in OBL are related to student participation is necessary for quality improvement of OBL. This knowledge can help professionals determine what they need to improve in their institution and how to prioritize those improvements. In this study, we report on the validation of a quality instrument with indicators related to quality dimensions present in quality management frameworks and important success factors that aid student participation in OBL. These success factors are as follows: credibility, transparency, flexibility, accessibility, interactivity, personalization, and productivity. The partial least squares structural equation modelling (PLS‐SEM) method is suitable for validating complex models in studies where predictive accuracy is important. According to adult students, all success factors, except flexibility, are important for aiding OBL participation. Adult students perceive that the quality dimensions of learning activities and student support (related to interactivity) deserve priority in improving participation in OBL in adult education.     

Vessel wall characterization using quantitative MRI: what’s in a number?

The past decade has witnessed the rapid development of new MRI technology for vessel wall imaging. Today, with advances in MRI hardware and pulse sequences, quantitative MRI of the vessel wall represents a real alternative to conventional qualitative imaging, which is hindered by significant intra- and inter-observer variability. Quantitative MRI can measure several important morphological and functional characteristics of the vessel wall. This review provides a detailed introduction to novel quantitative MRI methods for measuring vessel wall dimensions, plaque composition and permeability, endothelial shear stress and wall stiffness. Together, these methods show the versatility of non-invasive quantitative MRI for probing vascular disease at several stages. These quantitative MRI biomarkers can play an important role in the context of both treatment response monitoring and risk prediction. Given the rapid developments in scan acceleration techniques and novel image reconstruction, we foresee the possibility of integrating the acquisition of multiple quantitative vessel wall parameters within a single scan session.     

Extending the field of view: a human-centred design perspective on 360° TV

Omnidirectional video (ODV) is a type of video that presents viewers with a new type of interactivity. It enables people to look around in a 360° view of the recorded dynamic scene as if they are controlling the camera themselves. ODV presents opportunities for new interactive television formats. The development of such new formats, however, is accompanied by challenges in terms of user experience and technical and creative development. In this article, we discuss issues and opportunities tied to televising ODV from a user perspective. These findings are the result of a human-centred design study. In this study, we introduced 20 potential users to ODV, as this was new to them. We gathered their feedback on the demonstration, and then encouraged them to envision suitable ODV-based enhancements of television genres. This article offers a discussion of both the methodology (including a form of laddering) applied in the study and the user research findings. We found that people see an added value in ODV under certain conditions (e.g. enabling exploration), but that there are also a number of bottlenecks such as the concern to miss key parts of a television programme while looking around.     

Effect of Internal Current Flow During the Sintering of Zirconium Diboride by Field Assisted Sintering Technology

Effect of electric current on sintering behavior and microstructure evolution of zirconium diboride (ZrB₂) was investigated using three different configurations of Field Assisted Sintering Technology/Spark Plasma Sintering. The current flow through the ZrB₂ compact was controlled by modifying the interface between the graphite punches and the electrical conductive powder. Boron nitride discs, graphite foils or direct contact with the graphite punches were the three different interfaces used in order to deflect, conduct or promote, respectively, the current during the sintering process of the electrically conductive ZrB₂ ceramics. The current flow during the sintering process triggered the elimination/reduction in B₂O₃, leading to faster diffusion rates at high temperatures and limiting the formation of B₄C secondary phase. This allows to control the final density, grain size (from 19.6 to 43.2 μm) and secondary phase formation (from 5.95 to 11.61 vol%) as well as the electrical resistivity (from 7.7 to 9.4 μΩ·cm) of the specimens.     

The Antibiotic Doxycycline Impairs Cardiac Mitochondrial and Contractile Function

Tetracycline antibiotics act by inhibiting bacterial protein translation. Given the bacterial ancestry of mitochondria, we tested the hypothesis that doxycycline—which belongs to the tetracycline class—reduces mitochondrial function, and results in cardiac contractile dysfunction in cultured H9C2 cardiomyoblasts, adult rat cardiomyocytes, in Drosophila and in mice. Ampicillin and carbenicillin were used as control antibiotics since these do not interfere with mitochondrial translation. In line with its specific inhibitory effect on mitochondrial translation, doxycycline caused a mitonuclear protein imbalance in doxycycline-treated H9C2 cells, reduced maximal mitochondrial respiration, particularly with complex I substrates, and mitochondria appeared fragmented. Flux measurements using stable isotope tracers showed a shift away from OXPHOS towards glycolysis after doxycycline exposure. Cardiac contractility measurements in adult cardiomyocytes and Drosophila melanogaster hearts showed an increased diastolic calcium concentration, and a higher arrhythmicity index. Systolic and diastolic dysfunction were observed after exposure to doxycycline. Mice treated with doxycycline showed mitochondrial complex I dysfunction, reduced OXPHOS capacity and impaired diastolic function. Doxycycline exacerbated diastolic dysfunction and reduced ejection fraction in a diabetes mouse model vulnerable for metabolic derangements. We therefore conclude that doxycycline impairs mitochondrial function and causes cardiac dysfunction.     

Two “Dual” Families of Nearly-Linear Codes over ℤ p , p odd

Since the paper by Hammons e.a. [1], various authors have shown an enormous interest in linear codes over the ring ℤ₄. A special weight function on ℤ₄ was introduced and by means of the so called Gray map ϕ : ℤ₄→ℤ₂ ² a relation was established between linear codes over ℤ₄ and certain interesting non-linear binary codes of even length. Here, we shall generalize these notions to codes over ℤ _p2 where p is an arbitrary prime. To this end, a new weight function will be proposed for ℤ _p2 . Further, properties of linear codes over ℤ _p2 will be discussed and the mapping ϕ will be generalized to an isometry between ℤ _p2 and ℤ _p ^p , resp. between ℤ _p2 ⁿ and ℤ _p ^pn . Some properties of Galois rings over ℤ _q will be described and two dual families of linear codes of length n = p ^m − 1, gcd(m, p) = 1, over ℤ _q will be constructed. Taking q = p ², their images under the new mapping can be viewed as a generalization of the binary Kerdock and the Preparata code, although they miss some of their nice combinatorial properties. Received: June 19, 2000; revised version: November 6, 2000     

Developing semantic VR-shops for e-Commerce

Increased bandwidth, cheaper and faster hardware, dedicated technology and the success of e-commerce make VR-shops feasible. VR-shops are similar to the e-shops currently available on the Web, with the difference that the products are visualized as 3D objects in a virtual world. Although VR-shops do not require sophisticated VR technology, they should be very flexible: it should be easy to add, remove and rearrange products; and to add, change or remove functionality. Therefore, an appropriate approach that can be used by a non-VR expert and which provides a short development time and easy maintenance is necessary. Also usability is very important because this is crucial for the success of VR-shops. In this paper, we present an approach to develop VR-shops that meet these requirements. It allows specifying a VR-shop using high-level conceptual specifications and in terms of domain terminology; semantics are captured by ontologies; existing product information can be incorporated; and the actual code is generated.