NMR microscopy of single neurons at 500 MHZ

Previous NMR microimaging studies at 360 MHz have demonstrated a clear differentiation between the nucleus and cytoplasm in isolated single neurons. In particular, theT ₂ of the cell nucleus is 2.5 times larger than that of the cytoplasm. In order to determine the magnitude of possibleT ₂ ^* influences on these observations, images of single cells have been obtained at 500 MHz using spin-echo and line-narrowing sequences. Comparison of the images acquired by the two sequences, and of the spin-echo images at 360 and 500 MHz, imply that anyT ₂ ^* contributions are relatively small. Consequently, the measuredT ₂ differences in spin-echo imaging represent a true difference in theT ₂ relaxation in the two cellular compartments.     

Actual daily dietary intake of selenium in Belgium, using duplicate portion sampling

The dietary selenium (Se) intake in Belgium has been re-evaluated. Duplicate meal collection, wet acid destruction and flow injection hydride generation atomic absorption spectrometry were used as techniques. The daily intake ranged from 28.4 g (Liège, Walloon part of the country) to 61.1 g (Vilvoorde, central part of the country). Compared with intakes recently published for other countries, the actual Belgian value corresponds to intermediate ranges of Se intake.

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Die aktuelle tägliche Selen-Aufnahme durch die Nahrung in Belgien, bestimmt durch doppelte Probenahme

Zusammenfassung Die Selen-Aufnahme durch die Nahrung in Belgien wurde neu bestimmt. Als Technik diente die doppelte Probenahme von Mahlzeiten, deren nasser Aufschluß und die Fließ-Injektions AAS mit Hydridgeneration. Die tägliche Aufnahme schwankt zwischen 28,4 und 61, 1 g. Im Vergleich zu Daten, die neuerdings aus anderen Ländern publiziert wurden, liegen die derzeitigen Werte aus Belgien im Mittelbereich.

     

Edge crossings in drawings of bipartite graphs

Systems engineers have recently shown interest in algorithms for drawing directed graphs so that they are easy to understand and remember. Each of the commonly used methods has a step which aims to adjust the drawing to decrease the number of arc crossings. We show that the most popular strategy involves an NP-complete problem regarding the minimization of the number of arcs in crossings in a bipartite graph. The performance of the commonly employed barycenter heuristic for this problem is analyzed. An alternative method, the median heuristic, is proposed and analyzed. The new method is shown to compare favorably with the old in terms of performance guarantees. As a bonus, we show that the median heuristic performs well with regard to the total length of the arcs in the drawing.     

The liberalized δ-rule in free variable semantic tableaux

In this paper we have a closer look at one of the rules of the tableau calculus presented by Fitting [4], called the -rule. We prove that a modification of this rule, called the ⁺-rule, which uses fewer free variables, is also sound and complete. We examine the relationship between the ⁺-rule and variations of the -rule presented by Smullyan [9]. This leads to a second proof of the soundness of the ⁺-rule. An example shows the relevance of this modification for building tableau-based theorem provers.     

Representing and using legal knowledge in integrated decision support systems: DataLex WorkStations

There is more to legal knowledge representation than knowledge-bases. It is valuable to look at legal knowledge representation and its implementation across the entire domain of computerisation of law, rather than focussing on sub-domains such as legal expert systems. The DataLex WorkStation software and applications developed using it are used to provide examples. Effective integration of inferencing, hypertext and text retrieval can overcome some of the limitations of these current paradigms of legal computerisation which are apparent when they are used on a stand-alone basis. Effective integration of inferencing systems is facilitated by use of a (quasi) natural language knowledge representation, and the benefits of isomorphism are enhanced. These advantages of integration apply to all forms of inferencing, including document generation and casebased inferencing. Some principles for development of integrated legal decision support systems are proposed.     

High-Resolution and Stable Ruddlesden–Popper Quasi-2D Perovskite Flexible Photodetectors Arrays for Potential Applications as Optical Image Sensor

The development of an efficient fabrication route to achieve high-resolution perovskite pixel array is key for large-scale flexible image sensor devices. Herein, a high-resolution and stable 10 × 10 flexible PDs array based on formamidinium(FA⁺) and phenylmethylammonium (PMA⁺) quasi-2D (PMA)₂FAPb₂I₇ (n = 2) perovskite is demonstrated by developing SiO₂-assisted hydrophobic and hydrophilic treatment process on polyethylene terephthalate substrate. By introducing Au nanoparticles (Au NPs),  the perovskite film quality is improved and grain boundaries are reduced. The mechanism by which Au NPs upgrade the photoelectric quality of perovskite is mainly revealed by glow discharge-optical emission spectroscopy (GD-OES) and grazing-incidence wide-angle X-ray scattering (GIWAXS). To further improve the photoelectric performance of the devices, a post-treatment strategy with formamidinium chloride (FACl) is used . The optimized flexible PDs arrays show excellent optoelectronic properties with a high responsivity of 4.7 A W⁻¹, a detectivity of 6.3 × 10¹² Jones, and a broad spectral sensitivity. The device also exhibits excellent electrical stability even under severe bending and excellent flexural strength, as well as excellent environmental stability. Finally, the integrated flexible PDs arrays are used as sensor pixels in an imaging system to obtain high-resolution imaging patterns, demonstrating the imaging capability of the PDs arrays.     

Imposing temporal consistency on deep monocular body shape and pose estimation

Computational Visual Media - Accurate and temporally consistent modeling of human bodies is essential for a wide range of applications, including character animation, understanding human social...     

Instructing students on effective sequences of examples and problems: Does self-regulated learning improve from knowing what works and why?

Nowadays, students often practice problem-solving skills in online learning environments with the help of examples and problems. This requires them to self-regulate their learning. It is questionable how novices self-regulate their learning from examples and problems and whether they need support. The present study investigated the open questions (1) to what extent students' (novices) task selections align with instructional design principles and (2) whether informing them about these principles would improve their task selections, learning outcomes, and motivation. Higher education students (N = 150) learned a problem-solving procedure by fixed sequences of examples and problems (FS-condition), or by self-regulated learning (SRL). The SRL participants selected tasks from a database, varying in format, complexity, and cover story, either with (ISRL-condition) or without (SRL-condition) watching a video detailing the instructional design principles. Students' task-selection patterns in both SRL conditions largely corresponded to the principles, although tasks were built up in complexity more often in the ISRL-condition than in the SRL-condition. Moreover, there was still room for improvement in students' task selections after solving practice problems. The video instruction helped students to better apply certain principles, but did not enhance learning and motivation. Finally, there were no test performance or motivational differences among conditions. Although these findings might suggest it is relatively ‘safe’ to allow students to independently start learning new problems-solving tasks using examples and problems, caution is warranted: It is unclear whether these findings generalize to other student populations, as the students participating in this study have had some experience with similar tasks or learning with examples. Moreover, as there was still room for improvement in students' task selections, follow-up research should investigate how we can further improve self-regulated learning from examples and practice problems.     

Defect‐Laden MoSe2 Quantum Dots Made by Turbulent Shear Mixing as Enhanced Electrocatalysts

A high density of edge sites and other defects can significantly improve the catalytic activity of layered 2D materials. Herein, this study demonstrates a novel top‐down strategy to maximize catalytic edge sites of MoSe₂ by breaking up bulk MoSe₂ into quantum dots (QDs) via “turbulent shear mixing” (TSM). The ultrasmall size of the MoSe₂ QDs provides a high fraction of atoms in reactive edge sites, thus significantly improving the catalytic activities. The violent TSM further introduces abundant defects as additional active sites for electrocatalytic reactions. These edge‐proliferated and defect‐laden MoSe₂ QDs are found to be efficient electrocatalysts for the hydrogen evolution reaction, and useful as counter electrodes in dye‐sensitized solar cells. The work provides a new paradigm for creating edge‐proliferated and defect‐rich QDs from bulk layered materials.