Search

Whether or not world chess champion Alexander Alekhine was a “Nazi” is a question that the international chess community has been asking for decades. Beyond a series of anti-Semitic articles, however, little was known about his actions and behaviour during the Second World War, and the available information has been pieced together in a disjointed and incomprehensible way. The following article demonstrates that existing information and new sources combine to form a coherent narrative when Alekhine’s actions and behaviour are understood as a dual strategy by which he sought to regain his nearly ideal life before the outbreak of the Second World War. Indeed, his life in safety among the upper echelon of society as a recognised world chess champion was at stake. Alekhine saw an initial way out by pursuing a world championship match against José Raúl Capablanca and emigration to South America; he followed another avenue by approaching the National Socialist regime. Starting in March 1941, he chose to pursue both paths in parallel and in public view. Shortly after Capablanca’s death in March 1942, Alekhine entered into a contractual relationship with the Institute for German Eastern Work (Institut für Deutsche Ostarbeit, IDO) in Krakow, thanks to intervention on the part of Governor General (Generalgouverneur) Hans Frank himself. Until the fall of 1943, Alekhine essentially remained a playing chess master in the service of the Greater German Chess Federation (Großdeutscher Schachbund, GSB), which in turn was a compliant tool of the National Socialist regime. By promoting anti-Semitic propaganda in line with the regime’s position, Alekhine clearly crossed the line between chess and politics time and again.

The influence of the core diameter and the fiber length on the beam quality of the transmitted beam was investigated theoretically and experimentally for highly multimode step-index fibers with a numerical aperture of 0.22 using a fully monolithic setup. We show that it is possible to maintain a nearly diffraction-limited beam quality ( M $^{2}\boldsymbol{\approx }$ 1.3) through 100 m long multimode fibers. For a core diameter of $60\,\boldsymbol{\mu}$ m and a fiber length of 380 m one can still deliver a beam with an M $^{2}$ value of 2.1. The high-power suitability of this approach was shown by transmitting 1 kW of power through a 100 m long fiber with a core diameter of $60\,\boldsymbol{\mu}$ m without the onset of stimulated Raman scattering while maintaining a nearly diffraction-limited beam quality ( M $^{2} \boldsymbol{\approx }$ 1.3).

International audience; We report on a comprehensive analysis of the polarization-maintaining behavior of two different kinds of inhibited-coupling guiding hollow-core fibers and the influence of fiber bends. A phase shift induced degradation of the incident linear polarization state was observed due to a mismatch of the propagation constants of the orthogonally polarized LP01-modes of the fiber. This effect was predicted theoretically and is corroborated with numerical simulations and experimental results. It is shown that the phase shift is enhanced by a reduction of the bending radius of the fiber, but can be circumvented by orienting the polarization of the injected beam either parallel or perpendicular to the plane of bending.

We report on continuous-wave (cw) laser experiments with a high-quality and large-size Yb:Lu2O3 polycrystalline transparent ceramic in a thin-disk laser oscillator. An output power of up to 1190 W was achieved in multimode operation with an optical efficiency of 60.3%. In fundamental-mode operation, a cw output power of 409 W was extracted with an optical efficiency of 35.6% and a beam propagation factor of M2 = 1.11.

In view of the growing demand for fiber beam delivery in manufacturing systems with close to diffraction-limited beam quality, we present an analysis of the propagation of a nearly diffraction-limited laser beam through 5 to 10 m long multimode step-index fibers with a numerical aperture of 0.111 and core diameters of up to 80 $\mu$ m. The influence of the launching conditions are investigated theoretically and experimentally by varying the beam size of the input beam. At a core diameter as high as 80 $\mu$ m, corresponding to a mode field area of 2800 $\mu$ m2, and an optimum launching condition, the transmitted M2 was measured to be around 1.3. It is shown that bending of the fibers down to radii as small as 2 cm barely influences the beam quality factor of the transmitted beam for all the tested fibers as the M2 was always found to be smaller than 1.5. The threshold of stimulated Raman scattering was measured to be around 60 kW for a fiber loosely placed on the table ( $\text{r}_{\text{bend}}$ $\geq$ 25 cm) with a total length of 10 m and a core diameter of 80 $\mu$ m.

Bacterial cellulose (BC) has a broad range of applications in biomedical fields and cosmetics. Applied as wound dressing, BC tends to stick to the sore especially upon drying, and hydrophobization improves its performance in this regard. This article reports a facile and rapid yet a highly efficient approach for BC hydrophobization through direct polymerization of ethyl 2-cyanoacrylate on the BC fibers. The modified material preserves the favorable porous structure of the matrix material while displaying significantly higher hydrophobicity and significantly decreased stickiness to the wound. The BC surface can be modified in 15 min. Overall, this can be considered a ready-to-apply approach for the fabrication of BC wound dressings with enhanced performance. The modification was demonstrated to improve the material’s biocompatibility and to introduce antimicrobial activity (immortalized human fibroblast assay).

Bacterial cellulose (BC) hydrogels are among the most efficient materials already being used for the treatment of complex wounds. The moist environment provided by the BC dressing is a key feature assuring efficient wound recovery. Improving the dressings' moisture-holding ability facilitates its application and leads to an economically preferable extended wear time. To produce materials with reduced moisture loss, BC dressings were impregnated with a secondary hydrophilic component: alginate. The feasibility of an industrial fabrication of this composite was evaluated on pilot scale equipment. It was shown that the procedure can easily be scaled up without significantly increasing the manufacturing time. The resultant composite possessed improved water-retention properties, providing a smooth dressing exchange as demonstrated by a wound-imitating model. The new materials were moreover shown to be compatible with an antimicrobially active compound, which assures their efficiency in the treatment of highly colonized wounds.

We report on the functionalization of wet bacterial cellulose sheets towards photo-bactericidal materials that produce singlet oxygen (1O2) upon illumination. Pre-modification was carried out by a silane chemistry approach in order to make the cellulosic material accessible to Cu(I)-catalyzed azide-alkyne click chemistry. This way, two xanthene-derived photosensitizers were covalently grafted onto the surface of the silanized bacterial cellulose sheets. The obtained materials and photosensitizers were comprehensively characterized by means of FTIR, NMR, elemental analysis, UV/Vis absorption and fluorescence techniques, including nanosecond laser flash photolysis, for the determination of respective triplet state and singlet oxygen quantum yields. The photomicrobicidal activity was tested under white light illumination against gram-negative as well as gram-positive bacteria, including Escherichia coli, Bacillus subtilis and Staphylococcus aureus, as well as fungi (Candida albicans and Aspergillus brasiliensis). The results show type II photochemical antimicrobial activity against S. aureus and B. subtilis, but no effect against gram-negative bacteria and fungi.

We analyze the requirements and demonstrate good beam quality transportation over several hundred meters in highly multimode step-index fibers. The beam quality factor is preserved over 100m (M2≈1.3) and degrades linearly to M2≈2.0 at 300m.

Within recent years many ultra-short pulsed lasers with extremely high pulse energies as well as average powers were developed for laser material processing. To flexibly guide the beam from the laser to the workpiece hollow-core photonic crystal fibers (HC-PCF) have shown to be the best and unique choice to deliver these high peak power pulses. Also it has been reported that to largely reduce the overlap of the mode in air and the surrounding silica, inhibited coupling (IC) guiding HC-PCF is the most adequate choice [1].

A major advantage of solid-state lasers emitting in the 1 μm wavelength range is the possibility of using optical fibers for flexible beam delivery. This is already state of the art in laser material macro-processing with multimode beams. For modern high-brightness lasers with a diffraction-limited beam the guiding is restrained to a few meters or low powers due to nonlinear effects, mainly to Stimulated Raman Scattering (SRS) [1].

In the present work, bacterial cellulose (BC) was analyzed for its chromophore content with the chromophore release and identification (CRI) method. In aged BC, seven chromophores were unambiguously identified, despite their very low (ppb) presence. The compounds contain 2-hydroxy-[1,4]benzoquinone, 2-hydroxyacetophenone and 5,8-dihydroxy-naphthoquinone moieties. These three classes of key chromophores had also been found in other celluloses such as bleached pulp, fiber and derivatives. The detection of chromophores in lignin-free BC confirms that the chromophores are formed from oxidized and degraded carbohydrate material rather than lignin fragments. Samples that were insufficiently purified before the aging step also yielded three N-heterocyclic compounds. They originated from tryptophan moieties in residual adhering protein and protein degradation products. N-Heteropentacycles 9 and 10 showed strong adsorption onto cellulosic surfaces, and that adsorption aided oxidation of cyclohexadiene derivative 9 into the corresponding aromatic and intensely yellow system 10, consistent with the strain-induced bond localization theory. In purified fresh BC, no chromophores were detectable by the CRI method. The present contribution is the first report on defined chromophoric structures isolated from BC.

Usability testing has long been considered a gold standard in evaluating the ease of use of software and websites-producing metrics to benchmark the experience and identifying areas for improvement. However, logistical complexities and costs can make frequent usability testing infeasible. Alternatives to usability testing include various forms of expert reviews that identify usability problems but fail to provide task performance metrics. This case study describes a method by which multiple teams of trained evaluators generated task usability ratings and compared them to metrics collected from an independently run usability test on three software products. Although inter-rater reliability ranged from modest to strong and the correlation between actual and predicted metrics did establish fair concurrent validity, opportunities for improved reliability and validity were identified. By establishing clear guidelines, this method can provide a useful usability rating for a range of products across multiple platforms, without costing significant time or money.

The moisture management property of compression bandages is a critical factor influencing the state of well-being and compliance of patients with venous and lymphatic disorders. The thermal resistance and water vapor transmission rate of compression bandages were assessed using a limb model, which allows bandage application under tension and provides valuable insight on moisture distribution across the entire ensemble under simulated wear conditions. The performance of eight commercially available two- and four-layer compression bandages was evaluated based on measurement of physical parameters, such as thickness and mass per area, moisture sorption, air permeability, water vapor permeability, and moisture distribution during the simulated wear test. The gravimetrically determined water vapor transmission of the different bandages varied from 279 to 341 g m−2 h−1. Low air permeability of padding or cohesive can indicate possible moisture barrier properties, which could cause undesirable moisture accumulation inside the bandage. Robust reproducibility of the test, along with rapidity and ease of manipulation, allows comparison between the individual products and could provide the basis of dressing performance standardization.

Usability research is dramatically affecting product design in the 21st century. Five user experience and research managers from cutting-edge Silicon Valley companies discuss the strategic relationship between user research and product design, organizational processes that succeed in helping user research and user experience design improve products, and what's different about user research and user experience design for Internet companies and Web sites.

A new type of DC-powered plasma source (LARGE) was developed and evaluated for continuous plasma-enhanced (PE) CVD under atmospheric pressure. The linear extended emanating plasma sheet was scaled-up to various working widths with the result that a half meter range has already been achieved. A CVD reactor was designed for continuous deposition of non-oxide materials. The reactor operates in a remote atmospheric pressure (AP) PECVD configuration with typical deposition rates of 5–50 nm s–1 (static) and 0.1–1.0 nm m s–1 (dynamic). The potential application range of the ArcJet-CVD technology was evaluated by screening studies with various substrates, (stainless steel, glass, silicon wafers) and coating materials (silica, carbon, silicon nitride). In-situ process characterization has been provided by both optical emission and Fourier transform infrared (FTIR) spectroscopy. A range of atomic and molecular intermediates, precursor fragments, and reaction products were identified, leading to the conclusion that a complete conversion of the element-organic precursors into an inorganic layer takes place.

Deep unification- (constraint-)based grammars are usually hand-crafted. Scaling such grammars from fragments to unrestricted text is time-consuming and expensive. This problem can be exacerbated in multilingual broad-coverage grammar development scenarios. Cahill et al. (2002, 2004) and O’Donovan et al. (2004) present an automatic f-structure annotation-based methodology to acquire broad-coverage, deep, Lexical-Functional Grammar (LFG) resources for English from the Penn-II Treebank. In this paper we show how this model can be adapted to a multilingual grammar development scenario to induce robust, wide-coverage, PCFG-based LFG approximations for German from the TIGER Treebank. We show how the architecture of LFG, in particular the distinction between c-structure and f-structure representations, facilitates multilingual, treebank-based unification grammar induction, allowing us to cross-linguistically reuse the lexical extraction and parsing modules from O’Donovan et al. (2004) and Cahill et al. (2004), respectively. We evaluate our grammars against the PARC 700 Dependency Bank (King et al., 2003), against dependency structures for 2000 held-out sentences from the TIGER Corpus as well as against a hand-crafted dependency gold standard for 100 TIGER trees. Currently, our resources achieve 81.79% f-score against the PARC 700, a 2.19% improvement over the best result reported for a hand-crafted grammar in Kaplan et al. (2004), 74.6% against the 2000 held-out TIGER dependency structures and 71.08% against the 100-sentence TIGER gold standard, with substantially improved coverage compared to hand-crafted resources. We have since applied our methodology to induce wide-coverage LFG resources for Chinese (Burke et al., 2004b) from the Penn Chinese Treebank (Xue et al., 2002) and for Spanish from the CAST3LB Treebank (Civit, 2003).

The length of fuzz and pill formed on regenerated cellulosic knitt fabrics after washing and drying (WD) was determined by electrical resistivity measurements perpendicular to the plane of fabric. ...

This paper reports on the TIGER Treebank, a corpus of currently 40,000 syntactically annotated German newspaper sentences. We describe what kind of information is encoded in the treebank and introduce the different representation formats that are used for the annotation and exploitation of the treebank. We explain the different methods used for the annotation: interactive annotation, using the tool ANNOTATE, and LFG parsing. Furthermore, we give an account of the annotation scheme used for the TIGER treebank. This scheme is an extended and improved version of the NEGRA annotation scheme and we illustrate in detail the linguistic extensions that were made concerning the annotation in the TIGER project. The main differences are concerned with coordination, verb-subcategorization, expletives as well as proper nouns. In addition, the paper also presents the query tool TIGERSearch that was developed in the project to exploit the treebank in an adequate way. We describe the query language which was designed to facilitate a simple formulation of complex queries; furthermore, we shortly introduce TIGER in, a graphical user interface for query input. The paper concludes with a summary and some directions for future work.

Friction between fibers inside yarns is generally important for determining the physical behavior of textiles. The tendency of cellulosic fibers to slide in a yarn directly influences the extent of fuzz formation during abrasive treatment. This paper presents a test method to determine the slipping behavior of fibers in a yarn as a function of yarn twist. Different kinds of cellulosic fibers tested with the method include lyocell, modal, viscose, and cotton. To obtain a quantitative measure, a mathematical model is established to estimate the force for fibers slipping in a yam as a function of two basic fiber parameters. μ and α: μ is the coefficient of friction of fibers in a yam and α describes fiber adherence. As a result of the calculations, these fibers can be characterized by their frictional properties in a yarn.

We report, for the first time, on the generation, in a highly multimode gradient-index fiber, of supercontinuum (from visible to near infrared) with up to 54 mW of average power and emitting in LP0n modes.

Mobile application app stores are a critical source of information about risk in an uncertain environment. App stores ought to assess and communicate the risk associated with an installation so that users are discouraged from installing risky or harmful apps in app stores. However, only a limited number of studies offer designers information about how to communicate risk effectively. We focused on the user's trust associated with security information stemming from crowd-sourced evaluations compared to those generated from an automated system. Both of these sources of security information are pervasively used to indicate possible risk associated with an app. We investigated whether biases exist for a particular source of information given similar amount of security information being available. We found that participants preferred to install apps rated by automation to those rated by humans despite equivalence in stated risk. Further, we found evidence of a gender difference in trust in automation.

© Exact and reproducible dispensing of liquids is a prerequisite for many applications in medical and molecular biology laboratories. The performance of test systems is largely dependent upon the exact proportions of the individual reaction components in an assay. Modern pipettes enable the user to manually dispense amounts of liquid down to about 0.1 μL. Using this mature technology, even users with little experience can dispense such small amounts of liquid without fearing the effects on the precision of the results. Despite the great importance of precise liquid handling in research and diagnostics, little attention is often paid to the hardware responsible for it, namely the pipettes. Here, I will give an overview of the technical principles of pipettes and discuss the characteristics of different systems defined by different methods of construction. I will also classify them by their applications. Other factors that affect the precision and accuracy of dispensing liquids will also be examined. Some practical tips will be given outlining even more precise methods of working.

Widely varying experimental values for activation energy and pre-exponential factors for silver have been reported in the literature. A model is developed to provide an interpretation of possible interactions of the analyte with the graphite for different experimental conditions in graphite furnace atomic absorption spectrometry (GFAAS). It is formulated as a Monte Carlo study. By abandoning the concept of fixed parameters, it is shown that the experimental values are close to the theoretically predicted values. Satisfactory correlation with all experimental absorbance profiles is obtained with a very simple formulation for the temporal distribution of the particles using calculated diffusion coefficients.

In this interactive session, a panel of experts will discuss and debate an emerging and pressing issue: To have maximum impact on the user experience, how and where should a User Research team be structured within a corporation whose business depends on the development of successful interactive products through cross-functional collaboration? This has significant implications for organizations such as user experience, marketing, design, strategy, and academic programs preparing students entering corporate environments.

In this paper we present a method for greatly reducing parse times in LFG parsing, while at the same time maintaining parse accuracy. We evaluate the methodology on data from English, German and Norwegian and show that the same patterns hold across languages. We achieve a speedup of 67% on the English data and 49% on the German data. On a small amount of data for Norwegian, we achieve a speedup of 40%, although with more training data we expect this figure to increase.