Epistemic Actions as Resources

We provide an algebraic semantics together with a sound andcomplete sequent calculus for information update due to epistemicactions. This semantics is flexible enough to accommodate incompleteas well as wrong information e.g. due to secrecy and deceit,as well as nested knowledge. We give a purely algebraic treatmentof the muddy children puzzle, which moreover extends to situationswhere the children are allowed to lie and cheat. Epistemic actions,that is, information exchanges between agents , are modeled as elements of a quantale. The quantale acts on an underlying Q-rightmodule of epistemic propositions and facts. The epistemic content is encoded by appearance maps,one pair and of (lax) morphisms for each agent , which preserve the module and quantale structurerespectively. By adjunction, they give rise to epistemic modalities,capturing the agents' knowledge on propositions and actions.The module action is epistemic update and gives rise to dynamicmodalities—cf. weakest precondition. This model subsumesthe crucial fragment of Baltag, Moss and Solecki's dynamic epistemiclogic, abstracting it in a constructive fashion while introducingresource-sensitive structure on the epistemic actions.     

Visual querying and analysis of large software repositories

We present a software framework for mining software repositories. Our extensible framework enables the integration of data extraction from repositories with data analysis and interactive visualization. We demonstrate the applicability of the framework by presenting several case studies performed on industry-size software repositories. In each study we use the framework to give answers to one or several software engineering questions addressing a specific project. Next, we validate the answers by comparing them with existing project documentation, by interviewing domain experts and by detailed analyses of the source code. The results show that our framework can be used both for supporting case studies on mining software repository techniques and for building end-user tools for software maintenance support.

Achieving Efficient Electrocatalytic Oxygen Evolution in Acidic Media on Yttrium Ruthenate Pyrochlore through Cobalt Incorporation

The development of electrocatalysts for the oxygen evolution reaction (OER) especially in acidic media remains the major challenge that still requires significant advances, both in material design and mechanistic exploration. In this study, the incorporation of cobalt in Y_2-xCo_xRu₂O_7−δ results in an ultrahigh OER activity because of the charge redistribution at e_g orbitals between Ru and Co atoms. The Y1.₇₅Co_0.25Ru₂O_7−δ electrocatalyst exhibits an extremely small overpotential of 275 mV in 0.5 m H₂SO₄ at the current density of 10 mA cm⁻², which is smaller than that of parent Y₂Ru₂O_7−δ (360 mV) and commercial RuO₂ (286 mV) catalysts. The systematic investigation of the composition related to OER activity shows that the Co substitution will also bring other effective changes, such as reducing the bandgap, and creating oxygen vacancies, which result in fast OER charge transfer. Meanwhile, the strengthening of the bond hybridization between the d orbitals of metal (Y and Ru) and the 2p orbitals of O will intrinsically enhance the chemical stability. Finally, theoretical calculations indicate that cobalt substitution reduces the theoretical overpotential both through an adsorbate evolution mechanism and a lattice oxygen-mediated mechanism.     

Patch‐type Segmentation of Voxel Shapes using Simplified Surface Skeletons

We present a new method for decomposing a 3D voxel shape into disjoint segments using the shape's simplified surface‐skeleton. The surface skeleton of a shape consists of 2D manifolds inside its volume. Each skeleton point has a maximally inscribed ball that touches the boundary in at least two contact points. A key observation is that the boundaries of the simplified fore‐ and background skeletons map one‐to‐one to increasingly fuzzy, soft convex, respectively concave, edges of the shape. Using this property, we build a method for segmentation of 3D shapes which has several desirable properties. Our method segments both noisy shapes and shapes with soft edges which vanish over low‐curvature regions. Multiscale segmentations can be obtained by varying the simplification level of the skeleton. We present a voxel‐based implementation of our approach and illustrate it on several realistic examples.     

MoleView: an attribute and structure-based semantic lens for large element-based plots

We present MoleView, a novel technique for interactive exploration of multivariate relational data. Given a spatial embedding of the data, in terms of a scatter plot or graph layout, we propose a semantic lens which selects a specific spatial and attribute-related data range. The lens keeps the selected data in focus unchanged and continuously deforms the data out of the selection range in order to maintain the context around the focus. Specific deformations include distance-based repulsion of scatter plot points, deforming straight-line node-link graph drawings, and as varying the simplification degree of bundled edge graph layouts. Using a brushing-based technique, we further show the applicability of our semantic lens for scenarios requiring a complex selection of the zones of interest. Our technique is simple to implement and provides real-time performance on large datasets. We demonstrate our technique with actual data from air and road traffic control, medical imaging, and software comprehension applications.     

Recirculating immunomagnetic separation and optimal enrichment conditions for enhanced detection and recovery of low levels of Escherichia coli O157:H7 from fresh leafy produce and surface water

The objective of this study was to develop a rapid, simple method for enhanced detection and isolation of low levels of Escherichia coli O157:H7 from leafy produce and surface water using recirculating immunomagnetic separation (RIMS) coupled with real-time PCR and a standard culture method. The optimal enrichment conditions for the method also were determined. Analysis of real-time PCR data (C(T) values) suggested that incubation of lettuce and spinach leaves rather than rinsates provides better enrichment of E. coli O157:H7. Enrichment of lettuce or spinach leaves at 42 degrees C for 5 h provided better detection than enrichment at 37 degrees C. Extended incubation of surface water for 20 h at 42 degrees C did not improve the detection. The optimized enrichment conditions were also employed with modified Moore swabs, which were used to sample flowing water sites. Positive isolation rates and real-time PCR results indicated an increased recovery of E. coli O157:H7 from all samples following the application of RIMS. Under these conditions, the method provided detection and/or isolation of E. coli O157:H7 at levels as low as 0.07 CFU/g of lettuce, 0.1 CFU/g of spinach, 6 CFU/100 ml of surface water, and 9 CFU per modified Moore swab. During a 6-month field study, modified Moore swabs yielded high isolation rates when deployed in natural watershed sites. The method used in this study was effective for monitoring E. coli O157:H7 in the farm environment, during postharvest processing, and in foodborne outbreak investigations.     

Aromatic diazenes containing azulen-1-yl moieties Part 2: The synthesis,characterization, electronic spectra and basicity of novel,bis aromatic diazenes containing two azulen-1-yl moieties

Bis aromatic diazenes which possess either two identical or two different azulene-1-yl groups substituted at either 1,3 or 1,4-positions in the bridging phenylene moiety were synthesized in good yield via diazotization of the 3- or 4-azulen-1-ylazo-phenylamines followed by coupling with azulene in a buffered medium. The electronic spectra of the synthesized compounds were analyzed by comparison with those of previously published compounds. The isosbestic points obtained by protonation of the compounds enabled their pK_a values to be determined.     

Silica encapsulating lanthanum complexes using the sol–gel technique

BACKGROUND: Because of its properties, silica gel is an excellent host for different compounds. Many types of chemical species (organics, organometallics, proteins, enzymes, etc.) can be encapsulated in xerogels, and the sol–gel technique has been shown to be very useful for this aim. RESULTS: Some host–guest systems based on silica and complexed lanthanum were prepared in order to develop fluorescence properties. Three pathways were used to prepare such systems: (1) obtaining the lanthanum complex with a dimethylsiloxane‐based ligand and its incorporation into a silica network; (2) preparation of a silica network having hydroxyazomethine groups and in situ lanthanum complexation; and (3) preparation of polydimethylsiloxane (PDMS)/silica composites that possess hydroxyazomethine groups on the silica and in situ lanthanum complexation. The sol–gel technique was used in all cases. CONCLUSION: The photophysical properties of the prepared compounds were evaluated using fluorescence spectroscopy. The investigations revealed that the systems belonging to the second series are the most fluorescent. In the third series, the presence of PDMS provokes a decrease of the fluorescence intensity, until its complete quenching when the PDMS content exceeds a certain threshold value. However, there is a range of silica/PDMS ratio for which fluorescent free‐standing films can be obtained. The presence of complexed lanthanum induces changes in the morphology of the silica/PDMS matrix, as evidenced by scanning electron microscopy studies. Copyright © 2008 Society of Chemical Industry     

The development of grain-orientation-dependent residual stressess in a cyclically deformed alloy

There have been numerous efforts to understand and control the resistance of materials to fracture by repeated or cyclic stresses. The micromechanical behaviours, particularly the distributions of stresses on the scale of grain size during or after mechanical or electrical fatigue, are crucial to a full understanding of the damage mechanisms in these materials. Whether a large microstress develops during cyclic deformation with a small amount of monotonic strain but a large amount of accumulated strain remains an open question. Here, we report a neutron diffraction investigation of the development of intergranular stresses, which vary as a function of grain orientations, in 316 stainless steel during high-cycle fatigue. We found that a large intergranular stress developed before cracks started to appear. With further increase of fatigue cycles, the intergranular stress decreased, while the elastic intragranular stored energy continued to grow. One implication of our findings is that the ratio between the intergranular and intragranular stored energies during various stages of fatigue deformation may validate the damage mechanism and can be used as a fingerprint for monitoring the state of fatigue damage in materials.