How does wage polarization affect productivity? The case of Spanish regions

The effect of wage polarization on total factor productivity (TFP) in the Spanish regions between 2004 and 2012 is analysed using dynamic panel estimates. The main finding of this research is that there seems to be some evidence that polarization can affect productivity negatively. Although the specification of the models seems to be correct, the time period studied is brief, so these results should be interpreted with caution.     

Retinoids downregulate vascular endothelial growth factor/vascular permeability factor production by normal human keratinocytes

PURPOSE: We describe the clinical presentation, angiographic findings, and clinical outcome in a group of patients with pseudoaneurysms treated by a new endovascular technique using Guglielmi electrolytically detachable platinum coils (GDCs). METHODS: We retrospectively reviewed the angiographic and clinical findings in a series of 11 patients with pseudoaneurysms occurring in a variety of locations: seven in the cavernous carotid artery, one in the petrous carotid artery, two in the anterior cerebral artery, and one in the cervical vertebral artery. RESULTS: All aneurysms were cured with GDC embolization. The only complication was a branch occlusion, which resolved with heparinization and produced no clinical sequelae. CONCLUSION: Pseudoaneurysms can be safely and effectively treated by embolization with GDCs. Consideration needs to be given to the anatomic location of the pseudoaneurysm and the acuity of onset. Treatment efficacy may by improved if there are bony confines around the aneurysm or if therapy takes place in the subacute period, when the wall of the pseudoaneurysm has matured and stabilized.     

Characterization Techniques for Hydroxyapatite Deposited by Plasma Spray on Hip Prosthesis

As part of a characterization research on hydroxyapatite (HAp) plasma deposits for hip prosthesis, crystallinity and residual stresses weredetemiined at the interface Hap'TA6V. A traditional method employed by several laboratories is based on X-ray diffraction by a powder mixture of the investigated HAp sample with a standard of crystallinity Al₂O₃ Four new methods were investigated for determining the crystallinity of HAp sample, two of which are based on x-ray diffraction, one on neutron diffraction and one on the infrared absorption spectrometry. Whereas the three techniques require the use of powders, the neutron technique can be applied also to the intact HAp deposits. All four methods provide reasonable results, not very different one from each other, with a greater accuracy than for the x-ray and IR methods.     

Polystyrene recycling processes by dissolution in ethyl acetate

This study evaluated the thermal, morphological, chemical, and mechanical properties of virgin and recycled polystyrene. The recycling process was carried out by dissolution of polystyrene (extruded and crystal) in ethyl acetate, followed by two processes for solvent removal: vaporization by direct contact with water at 85 °C in a tubular evaporator and vaporization during the extrusion process. For the samples produced by solvent evaporation in the tubular evaporator, there was practically no degradation on polymer chain, neither reduction in glass transition temperature. For the samples produced by solvent evaporation during the extrusion, a polymer chain degradation was noted by reduction in molar weight and in glass transition temperature. The FTIR evaluation suggests that polymer oxidative degradation, in both samples, was more pronounced in the extruded sample. The removal of plasticizing additives could be evidenced by the glass transition temperature increase in the recycled samples produced in the tubular evaporator. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46208.     

Surface functionalization by smart coatings: Stimuli-responsive binary polymer brushes

Heterogeneous binary polymer brushes consist of an assembly of polymer chains of two incompatible polymers that are attached by one end to the surface with sufficient grafting density. They have been investigated experimentally only for a short time. Those brushes can be used in the form of ultrathin polymeric layers as a versatile tool for surface engineering to tune physico-chemical surface characteristics as wettability, surface charge, chemical composition or morphology, and furthermore to create switchable and responsive surface properties. For the fabrication of these layers “grafting-from” (as radical polymerization at the interface) and “grafting-to” (as tethering of the polymer chains from solution) methods were developed and investigated in detail.     

Introducing semantic variables in mixed distance measures: Impact on hierarchical clustering

Today, it is well known that taking into account the semantic information available for categorical variables sensibly improves the meaningfulness of the final results of any analysis. The paper presents a generalization of mixed Gibert’s metrics, which originally handled numerical and categorical variables, to include also semantic variables. Semantic variables are defined as categorical variables related to a reference ontology (ontologies are formal structures to model semantic relationships between the concepts of a certain domain). The superconcept-based distance (SCD) is introduced to compare semantic variables taking into account the information provided by the reference ontology. A benchmark shows the good performance of SCD with respect to other proposals, taken from the literature, to compare semantic features. Mixed Gibert’s metrics is generalized incorporating SCD. Finally, two real applications based on touristic data show the impact of the generalized Gibert’s metrics in clustering procedures and, in consequence, the impact of taking into account the reference ontology in clustering. The main conclusion is that the reference ontology, when available, can sensibly improve the meaningfulness of the final clusters.     

Semantic similarity estimation from multiple ontologies

The estimation of semantic similarity between words is an important task in many language related applications. In the past, several approaches to assess similarity by evaluating the knowledge modelled in an ontology have been proposed. However, in many domains, knowledge is dispersed through several partial and/or overlapping ontologies. Because most previous works on semantic similarity only support a unique input ontology, we propose a method to enable similarity estimation across multiple ontologies. Our method identifies different cases according to which ontology/ies input terms belong. We propose several heuristics to deal with each case, aiming to solve missing values, when partial knowledge is available, and to capture the strongest semantic evidence that results in the most accurate similarity assessment, when dealing with overlapping knowledge. We evaluate and compare our method using several general purpose and biomedical benchmarks of word pairs whose similarity has been assessed by human experts, and several general purpose (WordNet) and biomedical ontologies (SNOMED CT and MeSH). Results show that our method is able to improve the accuracy of similarity estimation in comparison to single ontology approaches and against state of the art related works in multi-ontology similarity assessment.     

Phenolic compounds from winemaking waste and its antioxidant activity towards oxidation of rapeseed oil

The effects of extraction parameters on bioactive compound contents of winemaking waste extracts (WWE) and its effect on rapeseed oil oxidative stability were evaluated. Research showed that the total phenols and anthocyanin contents and antioxidant activity (AA) of WWE significantly depended on the extraction parameters. Increasing the temperature (60 °C) and time (5 h) of extraction and an addition of water to ethanol statistically improved the rate of active component extraction. HPLC analysis showed that procyanidin B_2, catechin, gallic acid, γ‐resorcylic acid and p‐coumaric acid were the major phenolic compounds of WWE. Important correlations between total phenolic compounds quantified by HPLC and both DPPH and (ferric reducing antioxidant power) (FRAP) values were found. WWE added to the oil at three different levels clearly slowed down the process of fatty acid oxidation, inhibiting hydroperoxide formation by about 86%, comparable with BHT, while it was more effective than that of α‐tocopherol. When using volatile compound formation as a marker of lipid oxidation, WWE at the level of 2000 ppm were the most effective inhibitors of the decomposition of hydroperoxides. The research showed that the WWE are a rich source of phenolic compounds with powerful antioxidant activities and are suitable for preventing rapeseed oil oxidation.