Exploiting structure in LTL synthesis

In this paper, we show how to exploit the structure of some automata-based construction to efficiently solve the LTL synthesis problem. We focus on a construction proposed in Schewe and Finkbeiner that reduces the synthesis problem to a safety game, which can then be solved by computing the solution of the classical fixpoint equation νX.Safe ∩ CPre(X), where CPre(X) are the controllable predecessors of X. We have shown in previous works that the sets computed during the fixpoint algorithm can be equipped with a partial order that allows one to represent them very compactly, by the antichain of their maximal elements. However the computation of CPre(X) cannot be done in polynomial time when X is represented by an antichain (unless P = NP). This motivates the use of SAT solvers to compute CPre(X). Also, we show that the CPre operator can be replaced by a weaker operator CPre _crit where the adversary is restricted to play a subset of critical signals. We show that the fixpoints of the two operators coincide, and so, instead of applying iteratively CPre, we can apply iteratively CPre _crit. In practice, this leads to important improvements on previous LTL synthesis methods. The reduction to SAT problems and the weakening of the CPre operator into CPre _crit and their performance evaluations are new.     

High energy resolution five-crystal spectrometer for high quality fluorescence and absorption measurements on an x-ray absorption spectroscopy beamline

Fluorescence detection is classically achieved with a solid state detector (SSD) on x-ray absorption spectroscopy (XAS) beamlines. This kind of detection however presents some limitations related to the limited energy resolution and saturation. Crystal analyzer spectrometers (CAS) based on a Johann-type geometry have been developed to overcome these limitations. We have tested and installed such a system on the BM30B/CRG-FAME XAS beamline at the ESRF dedicated to the structural investigation of very dilute systems in environmental, material and biological sciences. The spectrometer has been designed to be a mobile device for easy integration in multi-purpose hard x-ray synchrotron beamlines or even with a laboratory x-ray source. The CAS allows to collect x-ray photons from a large solid angle with five spherically bent crystals. It will cover a large energy range allowing to probe fluorescence lines characteristic of all the elements from Ca (Z = 20) to U (Z = 92). It provides an energy resolution of 1-2 eV. XAS spectroscopy is the main application of this device even if other spectroscopic techniques (RIXS, XES, XRS, etc.) can be also achieved with it. The performances of the CAS are illustrated by two experiments that are difficult or impossible to perform with SSD and the complementarity of the CAS vs SSD detectors is discussed.     

Molecular approaches to the assessment of biodiversity in aquatic microbial communities

For the past 20 years, the increased development and routine application of molecular-based techniques has made it possible to carry out detailed evaluations of the biodiversity of aquatic microbial communities. It also offers great opportunities for finding out how this parameter responds to various environmental stresses. Most of these approaches involve an initial PCR amplification of a target, which is generally located within the ribosomal operon. The amplification is achieved by means of primers that are specific to the organisms of interest. The second step involves detecting sequence variations in the PCR fragments either by a cloning/sequencing analysis, which provides a complete characterization of the fragments, or by an electrophoretic analysis, which provides a visual separation of the mixture of fragments according to sequence polymorphism (denaturing or temperature gradient gel electrophoresis, single strand conformation polymorphism) or length polymorphism (terminal-restriction fragment length polymorphism, automated ribosomal intergenic spacer analysis). Other non-PCR-based methods are also commonly used, such as fluorescence in-situ hybridization and DNA re-association analysis. Depending on the technique used, the information gained can be quite different. Moreover, some of these analyses may be rather onerous in terms of time and money, and so not always suitable for screening large numbers of samples. The most widely used techniques are discussed in this paper to illustrate the principles, advantages and shortcomings of each of them. Finally, we will conclude by evaluating the techniques and discussing some emerging molecular techniques, such as real-time PCR and the microarray technique.     

Temperature control during Spark Plasma Sintering and application to up-scaling and complex shaping

The determination and the homogeneity of the sample temperature during consolidation of powders by Spark Plasma Sintering (SPS) are addressed. Densifications were carried out in three different facilities differing by their constructors and their size. A structural transformation activated in a TiAl alloy was used as a marker of the sample temperature and finite element modeling were performed to evaluate the temperature at each point of the set-up. A good agreement between experimental and simulated data is exhibited. Alloys with identical microstructures were sintered and the homogeneity of the microstructure was better in the largest machines or when the sample was isolated by alumina disks.Large specimens with a diameter of 100 mm and a height of 60 mm were sintered, with the aim to achieve full densification and good microstructural control. On the basis of this temperature mastering, samples with complex shape were successfully densified. SEM post mortem observations confirmed the absence of porosities, and the expected microstructure as predicted by FEM calculations.     

Genetic Variants of GPER/GPR30, a Novel Estrogen-Related G Protein Receptor,Are Associated with Human Seminoma

Testicular germ cell tumors (TGCTs) are the most common solid cancers in young men, with an increasing incidence over several years. However, their pathogenesis remains a matter of debate. Some epidemiological data suggest the involvement of both environmental and genetic factors. We reported two distinct effects of estrogens and/or xeno-estrogens on in vitro human seminoma-derived cells proliferation: (1) an antiproliferative effect via a classical estrogen receptor beta-dependent pathway, and (2) a promotive effect via a non-classical membrane G-protein-coupled receptor, GPR30/GPER, which is only overexpressed in seminomas, the most common TGCT. In order to explain this overexpression, we investigated the possible association of polymorphisms in the GPER gene by using allele-specific tetra-primer polymerase chain reaction performed on tissue samples from 150 paraffin-embedded TGCT specimens (131 seminomas, 19 non seminomas). Compared to control population, loss of homozygous ancestral genotype GG in two polymorphisms located in the promoter region of GPER (rs3808350 and rs3808351) was more frequent in seminomas but not in non-seminomas (respectively, OR = 1.960 (1.172–3.277) and 7.000 (2.747–17.840); p < 0.01). These polymorphisms may explain GPER overexpression and represent a genetic factor of susceptibility supporting the contribution of environmental GPER ligands in testicular carcinogenesis.     

Key Fatty Acid Combinations Define Vascular Smooth Muscle Cell Proliferation and Viability

High plasma concentrations of free fatty acids (FFA) and insulin are common features in atherosclerotic patients with type 2 diabetes. FFA, according to their nature, can have various effects on vascular smooth muscle cells (VSMC). These cells play important roles throughout atherosclerosis pathogenesis, from plaque development to plaque instability. Thus, this study aims to assess the impact of two FFA combinations and insulin on murine VSMC viability. The two combinations contain the same FFA but at different ratios, one being richer in saturated fatty acids (SFA) and the other having a higher proportion of monounsaturated fatty acids (MUFA). Both combinations inhibited VSMC proliferation due to their pro-apoptotic potential, with SFA being the major inducers of apoptosis. However, the presence of oleic acid (OLA) attenuated this impact in a dose-dependent manner. OLA had also the capacity to reduce apoptosis rates more strongly when combined with a SFA than when used alone in VSMC treatments. This effect was significant only for specific proportions of these FFA and was even more effective in presence of insulin. These results highlight the presence of a competition between pro-apoptotic and anti-apoptotic mechanisms in VSMC that is dependent on FFA ratios (saturated vs. monounsaturated) and on insulinemia. They also underline the importance of the presence of MUFA such as OLA in diets containing high proportions of SFA.     

Hybrid analysis of surface wavefield data from Portland cement and asphalt concrete plates

Impact-echo and multi-channel analysis of surface wave (MASW) methods were combined for a hybrid analysis of multi-channel surface wavefield data sets to iteratively solve for the thickness, elastic modulus, and Poisson's ratio of Portland cement and asphalt concrete plates. The time-frequency method was used to evaluate the plate thickness resonance frequency of the zero group velocity component of the first-order symmetric Lamb wave mode for use in the impact-echo analysis. It was observed that the thickness resonance frequency may not be resolved using focusing or amplifying signal processing techniques when plate/base interface conditions result in weak reflection amplitudes. Hybrid analysis results compared favourably against longitudinal resonant frequency tests of both cast cylinders and drilled cores from Portland cement concrete plates. It was shown that the hybrid analysis technique can be used to provide accurate compression wave velocity estimates used in impact-echo surveys.     

Resolution-independent characteristic scale dedicated to satellite images.

We study the problem of finding the characteristic scale of a given satellite image. This feature is defined so that it does not depend on the spatial resolution of the image. This is a different problem than achieving scale invariance, as often studied in the literature. Our approach is based on the use of a linear scale space and the total variation (TV). The critical scale is defined as the one at which the normalized TV reaches its maximum. It is shown experimentally, both on synthetic and real data, that the computed characteristic scale is resolution independent.     

Study of the interfacial reactions between a bioactive apatite–mullite glass–ceramic coating and titanium substrates using high angle annular dark field transmission electron microscopy

Glass of generic composition SiO₂ · Al₂O₃ · P₂O₅ · CaO · CaF₂ will crystallise predominantly to apatite and mullite upon heat-treatment. Such ceramics are bioactive, osseoconductive, and have a high resistance to fracture. As a result, they are under investigation for use as biomedical device coatings, and in particular for orthopaedic implants. Previous work has shown that the material can be successfully enamelled to titanium with an interfacial reaction zone produced during heat treatment. The present study uses high angle annular dark field transmission electron microscopy (HAADF-TEM) to conduct a detailed examination of this region. Results show evidence of complex interfacial reactions following the diffusion of titanium into an intermediate layer and the production of titanium silicides and titanium phosphides. These results confirm previously hypothesised mechanisms for the bonding of silicate bioceramics with titanium alloys.