Manipulation of matter by electric and magnetic fields: Toward novel synthesis and processing routes of inorganic materials

The use of external electric and magnetic fields for the synthesis and processing of inorganic materials such as metals and ceramics has seen renewed interest in recent years. Electromagnetic energy can be utilized in different ways to improve or accelerate phase formation and stabilization, chemical ordering, densification and coarsening of particle-based materials (pore elimination and grain growth), and mechanical deformation (plasticity and creep). In these new synthesis and processing routes, the resulting microstructures and macroscopic material behavior are determined by the interaction of the applied fields with defects such as single or clustered point defects, dislocation networks, and interfaces. Multiscale experimental investigations and modeling are necessary to unveil the mechanisms underlying this field-assisted manipulation of matter.     

A SLIT THROUGH PHOTOGRAPHY

Post-war experimental and conceptual photography in former Yugoslavia has only rarely been the subject of detailed study and interpretation. In considering this period, it is necessary to take into account several factors, including the absence of permanent exhibition spaces for photography, the lack of magazines in which photographic themes were presented and discussed, the impossibility of studying the field of photography and, finally, the inadequate knowledge and application of contemporary criticism and theories of photography. Nevertheless, from the mid-1950s onwards it is possible to note a variety of innovations in the field, in terms of both form and subject-matter. This article considers rare instances of institutional support for progressive photography-related events and unique, intellectual-poetic works. After the break-up of Yugoslavia, there is a dominant tendency to nationalize art created in the former state, thus ignoring the specific Yugoslav cultural field as well as the European context. Based on a methodology which surpasses the national (but still acknowledges it) and searches for meaning within the broader socio-political space to which art is referring, the research aims to change the paradigm of the peripheral position and general ignorance of the circumstances under which this innovative practice emerges.     

Tree pattern mining with tree automata constraints

Most work on pattern mining focuses on simple data structures such as itemsets and sequences of itemsets. However, a lot of recent applications dealing with complex data like chemical compounds, protein structures, XML and Web log databases and social networks, require much more sophisticated data structures such as trees and graphs. In these contexts, interesting patterns involve not only frequent object values (labels) appearing in the graphs (or trees) but also frequent specific topologies found in these structures. Recently, several techniques for tree and graph mining have been proposed in the literature. In this paper, we focus on constraint-based tree pattern mining. We propose to use tree automata as a mechanism to specify user constraints over tree patterns. We present the algorithm CoBMiner which allows user constraints specified by a tree automata to be incorporated in the mining process. An extensive set of experiments executed over synthetic and real data (XML documents and Web usage logs) allows us to conclude that incorporating constraints during the mining process is far more effective than filtering the interesting patterns after the mining process.     

Noise peaks influence communication in the operating room. An observational study

Noise peaks are powerful distractors. This study focuses on the impact of noise peaks on surgical teams’ communication during 109 long abdominal surgeries. We related measured noise peaks during 5-min intervals to the amount of observed communication during the same interval. Results show that noise peaks are associated with less case-relevant communication; this effect is moderated by the level of surgical experience; case-relevant communications decrease under high noise peak conditions among junior, but not among senior surgeons. However, case-irrelevant communication did not decrease under high noise level conditions, rather there was a trend to more case-irrelevant communication under high noise peaks. The results support the hypothesis that noise peaks impair communication because they draw on attentional resources rather than impairing understanding of communication. As case-relevant communication is important for surgical performance, exposure to high noise peaks in the OR should be minimised especially for less experienced surgeons.

Practitioner Summary: This study investigated whether noise during surgeries influenced the communication within surgical teams. During abdominal surgeries, noise levels were measured and communication was observed. Results showed that high noise peaks reduced the frequency of patient-related communication, but did not reduce patient-irrelevant communication. Noise may negatively affect team coordination in surgeries.     

Persistent Scatterers Interferometry detects and measures ground subsidence in Lisbon

Results from the application of Persistent Scatterers Interferometry in Lisbon Metropolitan Area revealed two previously unknown subsiding urban areas: one (Laranjeiras) is located in the center of Lisbon; another (Vialonga) is to be found toward the North, in an industrial region crossed by Lisbon's main highway and railway lines. The two subsiding sectors are bordered by sharp velocity gradients, and the subsidence pattern appears partially delimited by mapped geologic faults. Surface geology and urbanization alone are unable to explain the phenomena. In the Vialonga area, the historical record of water pore pressure shows a clear decline of the levels (up to 65 m in 27 years), providing evidence of over-exploitation of groundwater resources. Limited information from wells drilled inside and outside the subsidence area points to a spatial correlation between the subsidence and the water pressure levels, and suggests that faults could be acting as hydraulic barriers in the aquifer system. The surface subsidence detected is probably caused by compaction of a clay-rich Oligocene-aged aquitard, led by over-exploitation of adjacent aquifers. The same Oligocene aquitard layer is present in the Laranjeiras area, immediately bellow a multi-layered sand-clay-limestone Miocene aquifer, but further work is needed to diagnose the possibility of over-exploitation of groundwater here. In this work we were able to independently confirm the PSI results, by comparing autonomous PSI results processed for the same geographical areas, and by comparing PSI with leveling and continuous GPS derived subsidence velocities, whose close match provided further ground validation of the space-borne PSI technique.     

Quantifying blood flow and wall shear stresses in the outflow tract of chick embryonic hearts

Wall shear stresses (WSS) exerted by blood flow on cardiac tissues modulate growth and development of the heart. To study the role of hemodynamic conditions on cardiac morphogenesis, here, we present a methodology that combines imaging and finite element modeling to quantify the in vivo blood flow dynamics and WSS in the cardiac outflow tract (OFT) of early chicken embryos (day 3 out of 21-day incubation period). We found a distinct blood flow field and heterogeneous distribution of WSS in the chicken embryonic heart OFT, which have physiological implications for OFT morphogenesis.     

Molecular modeling optimization of anticoagulant pyridine derivatives

Intravascular clotting remains a major health problem in the United States, the most prominent being deep vein thrombosis, pulmonary embolism and thromboembolic stroke. Previous reports on the use of pyridine derivatives in cardiovascular drug development encourage us to pursue new types of compounds based on a pyridine scaffold. Eleven pyridine derivatives (oximes, semicarbazones, N-oxides) previously synthesized in our laboratories were tested as anticoagulants on pooled normal plasma using the prothrombin time (PT) protocol. The best anticoagulant within the oxime series was compound AF4, within the oxime N-oxide series was compound AF4-N-oxide, and within the semicarbazone series, compound MD1-30Y. We also used a molecular modeling approach to guide our efforts, and found that there was good correlation between coagulation data and computational energy scores. Molecular docking was performed to target the active site of thrombin with the DOCK v5.2 package. The results of molecular modeling indicate that improvement in anticoagulant activities can be expected by functionalization at the three-position of the pyridine ring and by N-oxide formation. Results reported here prove the suitability of DOCK in the lead optimization process.     

Evaluating ASP and Commercial Solvers on the CSPLib

This paper deals with four solvers for combinatorial problems: the commercial state-of-the-art solver ILOG oplstudio, and the research answer set programming (ASP) systems dlv, smodels and cmodels. The first goal of this research is to evaluate the relative performance of such systems when used in a purely declarative way, using a reproducible and extensible experimental methodology. In particular, we consider a third-party problem library, i.e., the CSPLib, and uniform rules for modelling and instance selection. The second goal is to analyze the marginal effects of popular reformulation techniques on the various solving technologies. In particular, we consider structural symmetry breaking, the adoption of global constraints, and the addition of auxiliary predicates. Finally, we evaluate, on a subset of the problems, the impact of numbers and arithmetic constraints on the different solving technologies. Results show that there is not a single solver winning on all problems, and that reformulation is almost always beneficial: symmetry-breaking may be a good choice, but its complexity has to be carefully chosen, by taking into account also the particular solver used. Global constraints often, but not always, help opl, and the addition of auxiliary predicates is usually worth, especially when dealing with ASP solvers. Moreover, interesting synergies among the various modelling techniques exist.