Improving clustering by learning a bi-stochastic data similarity matrix

An idealized clustering algorithm seeks to learn a cluster-adjacency matrix such that, if two data points belong to the same cluster, the corresponding entry would be 1; otherwise, the entry would be 0. This integer (1/0) constraint makes it difficult to find the optimal solution. We propose a relaxation on the cluster-adjacency matrix, by deriving a bi-stochastic matrix from a data similarity (e.g., kernel) matrix according to the Bregman divergence. Our general method is named the Bregmanian Bi-Stochastication (BBS) algorithm. We focus on two popular choices of the Bregman divergence: the Euclidean distance and the Kullback?CLeibler (KL) divergence. Interestingly, the BBS algorithm using the KL divergence is equivalent to the Sinkhorn?CKnopp (SK) algorithm for deriving bi-stochastic matrices. We show that the BBS algorithm using the Euclidean distance is closely related to the relaxed k-means clustering and can often produce noticeably superior clustering results to the SK algorithm (and other algorithms such as Normalized Cut), through extensive experiments on public data sets.     

Electronic Meeting Systems Paradox

Although research has shown that electronic meeting systems (EMS) can improve meetings substantially, EMS are less prominent in organizations than the scientific community originally envisioned. The authors discuss this paradox on the basis of an extensive literature review. They derive success factors for EMS implementation from IS research and develop an implementation model for EMS on the basis of diffusion theory.     

Higher‐output more‐compact UHP lamp systems

Abstract— Projection systems have reached convincing performance with several thousand screen lumens created by systems of only a few liters in volume. With more than 10 lm/W they are the most efficient display systems realized today. The tremendous progress achieved up to now relies on the outstanding properties of the UHP lamp. The combination of high brightness with lifetimes extending up to more than 10,000 hours is ideal for projection applications. This paper will summarize some recent technological achievements: the volume of the lamp and driver system has been reduced by a factor of 10, exploiting a reduced ignition voltage as well as new optical concepts for the reflector. The optical performance of short‐arc projection lamps can be improved dramatically: a dichroic coating on one half of the UHP burner is applied to focus all light into one hemisphere. This allows for extremely compact reflector systems and an improvement by 20–30% in light collection.     

Algal growth inhibition test: does shading of coloured substances really matter?

Coloured substances are often assumed to behave differently in the algal growth inhibition test due to shading of the algae. We have investigated EU-notifications of new substances and found no significant differences in algal test results between colours and non-colours. A modified method to differentiate between shading and toxicity is not satisfactory, because the method used to determine the shading effect is incorrect. Due to the shaking of the test flasks in the algal test intermittent light conditions are achieved which lead to a higher growth rate than expected from proposed tests with constant reduced light conditions. This will result in overestimation of the shading effect and thus to underestimation of chemical toxicity. Furthermore, we showed in experiments with the reference substance potassium dichromate that reduced light can reduce the measurable toxicity of chemicals.Comparing our results with approaches proposed in the literature, a simple approach to reduce effects of undesired shading when testing coloured substances is to achieve light saturation for the algae by increasing illumination at least to the upper limit given in test guidelines (120 microEs(-1)m(-2)) and, optionally, to reduce the light path by choosing smaller test volumes.     

Stable Evaluation of Jacobian Matrices on Highly Refined Finite Element Meshes

In the adaptive finite element method, the solution of a p.d.e. is approximated by finer and finer meshes, which are controlled from error estimators. So, starting from a given coarse mesh, some elements are subdivided a couple of times. We investigate the question of avoiding instabilities which limit this process from the fact that nodal coordinates of one element coincide in more and more leading digits. To overcome this problem we demonstrate a simple mechanism for red subdivision of triangles (and hanging nodes) and a more sophisticated technique for general quadrilaterals.     

Xe NMR studies on carbon replicas of Y zeolite

¹²⁹Xe NMR spectroscopy of xenon gas adsorbed on carbon replicas of Y zeolite was carried out at room temperature. Corresponding carbon replicas have been prepared by using ethylene and HY zeolite in a pressure reactor. Xenon gas was adsorbed on the resulting carbon samples in the pressure range from 40 to 150 kPa. The plot of the chemical shift against xenon pressure was found to be a linear function in the investigated pressure range from 40 to 150 kPa. Intense and narrow peaks have been observed for the synthesized carbon samples indicating chemically pure samples. By comparison of the estimated chemical shift parameter δ_N→0 and the slope δ₁ of the shift versus density plots the existence of different pore sizes could be revealed. These observed differences can be attributed to different types of micropores generated by shrinkage effects during carbon liberation from the parent zeolite host. The obtained carbon replicas of Y zeolite were further characterized by elemental analysis, XPS, ¹³C MAS NMR and ESR spectroscopy.     

Göttinger Thesen zur gesetzlichen Regelung des Umgangs mit Patientenverfügung und Vorsorgevollmacht*

Ohne Zusammenfassung *Die G?ttinger Thesen wurden von der „AG Sterben und Tod“ in der Akademie für Ethik in der Medizin (AEM) erarbeitet. Als Mitglieder der AG stimmen diesen Thesen zu: Dr. theol. Ralph Charbonnier (Medizinethiker, Hannover), Dr. med. Wolf Diemer (Palliativmediziner, Greifswald), Evelyn Freitag (Krankenhausseelsorgerin, Hospizbeauftragte, Oldenburg), Regine Gadow (Allgemeinmedizinerin, Marbach am Neckar), Prof. Dr. med. Klaus Gahl (Internist, Braunschweig), Sylke Gei?end?rfer (Rechtsanw?ltin, Berlin), Prof. Dr. med. Peter Glogner (Internist, Salzgitter), Irmgard Hofmann M. A. (Pflegeethikerin, München), Dr. phil. Arnd T. May (Medizinethiker, Bochum), Dr. rer. med. Jutta Müller (Qualit?tsmanagementbeauftragte, Künzell), Dr. med. Gerald Neitzke (Medizinethiker, Hannover), Gita Neumann (Humanistischer Verband Deutschlands, Berlin), Martin Ostertag (Pastor, Hospizbeauftragter, Lüneburg), Wolfgang Putz (Rechtsanwalt, München), Udo Schlaudraff (Pastor i.R., G?ttingen), Dr. theol. Kurt W. Schmidt (Medizinethiker, Frankfurt/M.), Prof. Dr. rer. med. Dr. theol. Werner Schweidtmann (Medizinpsychologe, Lippstadt), Dr. phil. Alfred Simon (Medizinethiker, G?ttingen), Dr. med. Meinolfus Str?tling (An?sthesiologe, Medizinethiker, Lübeck), Andrea Tietze (Rechtsanw?ltin, G?ttingen), Petra Vetter (Rechtsanw?ltin, Stuttgart), Dr. med. Thela Wernstedt (Palliativmedizinerin, Hannover), Dr. med. Dietrich W?rdehoff (Internist, Palliativmediziner, Saarbrücken).

---

Rates and mechanisms of dust generation in oxygen steelmaking

To understand the mechnisms governing dust generation in oxygen steelmaking, dust samples were taken every min during the refining process from the dust‐laden off‐gas at the horizontal duct of the 200 t BOF vessel no.3 at TKS Dortmund. The oxygen blowing rate and hence the CO formation rate remained nearly constant during the entire blow. Dust content, particle size distribution, and chemical composition of the dust were determined with special attention to top‐charging of lime, scrap and fluxes. The dust consisted of very fine droplets (< 1 μm) most of which formed agglomerates in the size range 1 to 200 μm. As the Mn:Fe ratio in the dust samples was found to be nearly equal to that in the molten metal, evaporation processes did not noticeably contribute to dust generation, which is therefore caused almost entirely by bubble bursting. Top charging always raised the dust emission rate for a short period of time without altering the dust composition. Apparently, the material added from the top enhanced heterogeneous nucleation in the slightly supersaturated liquid metal. Except for the top‐charging effect, the dust generation rate decreased steadily with blowing time by a factor of about 10. The high momentum of the oxygen jet impinging on the melt surface causes numerous splashes to be ejected which after a parabolic flight fall back into the melt. These splashes quickly dissolve oxygen which forms CO and leads to bubble bursting on the splash surfaces. With decreasing carbon content the splashes tend to form a solidified shell during their flight so that oxygen pick up and CO formation rates decrease. The refining process is gradually shifted from the splashes to the bulk melt, where CO formation again leads to bubble bursting but the slag present above the metal melt acts as a filter for the film and jet droplets so that the total dust emission decreases strongly.     

Cysteine proteinase inhibitor Act d 4 is a functional allergen contributing to the clinical symptoms of kiwifruit allergy

Kiwifruit has become a frequent cause of fruit allergy in the recent years. The molecular basis of type I hypersensitivity to kiwifruit is attributed to 11 IUIS allergens, with Act d 1, Act d 2 and Act d 5 characterized in extenso. Evaluation of the allergenic properties of Act d 4, a cysteine proteinase inhibitor from green kiwifruit (Actinidia deliciosa) was performed in this study. Identity of the purified glycoprotein was determined by Edman degradation and by mass fingerprint whereby more than 90% of the primary structure of the mature kiwifruit cystatin was confirmed. Using MALDI TOF analysis, molecular masses of 10902.5 and 11055.2 Da were detected for Act d 4, respectively. Positive skin prick reactivity with Act d 4 was induced in three kiwifruit allergic patients, as well as the upregulation of CD63 and CD203c molecules in the basophile activation assay. The IgE reactivity was detected in dot blot analysis while Western blot analysis was negative using sera from six kiwifruit patients, suggesting the presence of conformational IgE epitopes on the Act d 4 molecule. As activator of effector cells in type I hypersensitivity Act d 4 is a functional allergen contributing to the clinical symptoms of kiwifruit allergy.