Consistency,availability, and partition tolerance in blockchain: a survey on the consensus mechanism over peer-to-peer networking

Annals of Telecommunications - Blockchain is a disruptive technology that relies on the distributed nature of the peer-to-peer network while performing an agreement, or consensus, a mechanism to...     

Images of a First‐Order Spin‐Reorientation Phase Transition in a Metallic Kagome Ferromagnet

First‐order phase transitions, where one phase replaces another by virtue of a simple crossing of free energies, are best known between solids, liquids, and vapors, but they also occur in a wide range of other contexts, including even elemental magnets. The key challenges are to establish whether a phase transition is indeed first order, and then to determine how the new phase emerges because this will determine thermodynamic and electronic properties. Here it is shown that both challenges are met for the spin reorientation transition in the topological metallic ferromagnet Fe₃Sn₂. The magnetometry and variable temperature magnetic force microscopy experiments reveal that, analogous to the liquid–gas transition in the temperature–pressure plane, this transition is centered on a first‐order line terminating in a critical end point in the field‐temperature plane. The nucleation and growth associated with the transition is directly imaged, indicating that the new phase emerges at the most convoluted magnetic domain walls for the high temperature phase and then moves to self‐organize at the domain centers of the high temperature phase. The dense domain patterns and phase coexistence imply a complex inhomogenous electronic structure, which can yield anomalous contributions to the electrical conductivity.     

Survey of 1012 moldy dwellings by culture fungal analysis: Threshold proposal for asthmatic patient management

Different countries have tried to define guidelines to quantify what levels of fungi are considered as inappropriate for housing. This retrospective study analyzes indoor fungi by cultures of airborne samples from 1012 dwellings. Altogether, 908 patients suffering from rhinitis, conjunctivitis, and asthma were compared to 104 controls free of allergies. Portuguese decree law no 118/2013 (PDL118), ANSES (a French environmental and health agency) recommendations, and health regulations of Besançon University Hospital were applied to determine the rates of non‐conforming dwellings, which were respectively 55.2%, 5.2%, and 19%. Environmental microbiological results and medical data were compared. The whole number of colonies per cubic meter of air was correlated with asthma (P < 0.001) and rhinitis (P = 0.002). Sixty‐seven genera and species were detected in bedrooms. Asthma was correlated to Aspergillus versicolor (P = 0.004) and Cladosporium spp. (P = 0.02). Thresholds of 300 cfu/m³ for A. versicolor or 495 cfu/m³ for Cladosporium spp. are able to discriminate 90% of the asthmatic dwellings. We propose a new protocol to obtain an optimal cost for indoor fungi surveys, excluding surface analyses, and a new guideline to interpret the results based on >1000 cfu/m³ of whole colonies and/or above threshold levels for A. versicolor or Cladosporium spp.     

The fracture process in quasi‐brittle materials simulated using a lattice dynamical model

The damage process in quasi‐brittle materials is characterized by the evolution of a micro‐crack field, followed by the joining of micro‐cracks, stress localization and crack instability. In network models, masses are lumped at nodal points which are interconnected by one‐dimensional elements with a bilinear constitutive relation, considering the energy consistency during the simulated process. In order to replicate the material imperfections, to render a realistic behaviour in damage localization, the model has not only random elastic and rupture properties, but also a geometric perturbation. In the present paper 2D plates with different levels of brittleness are simulated. The numerical results are presented in terms of global stress vs strain diagram, final network configuration, energy balance during the process and as geometric damage evolution. Therefore, the predictive potential of the lattice discrete element model to capture fracture processes in quasi‐brittle materials is demonstrated.     

International Regulations of Propolis Quality: Required Assays do not Necessarily Reflect their Polyphenolic‐Related In Vitro Activities

Propolis has been proposed as a polyphenolic‐rich natural product potentially able to be used for human consumption or even for medicinal proposes. To guarantee a minimum phenolic and flavonoid content and as consequence of their related‐biological activities, international requirements of propolis quality are commonly applied. In this work we assessed phenolic and flavonoid contents of propolis; the antioxidant capacity (toward peroxyl radicals and hypochlorous acid); the ability to generate nitric oxide (NO); and, finally the antimicrobial activity of 6 propolis samples from the VI region of Chile. Our results show that the total phenolic and flavonoid content of propolis samples are not always in agreement with their polyphenolic‐associated in vitro activities. For example, P03 and P06 samples showed the lowest (25 ± 4 GAE/g propolis) and the highest (105 ± 3 GAE/g propolis) total phenolic content, respectively. This was in agreement with flavonoid content and their Oxygen Radical Absorbance Capacity (ORAC) activity. However, this dependence was not observed toward HOCl, NO release and antimicrobial activity. Based on our results, we consider that, in order to guarantee the antioxidant or antimicrobial in vitro effects, the international regulations of propolis quality should contemplate the convenience of incorporating other simple analytical test such as ORAC or antimicrobial tests.     

Task Switching After Cerebellar Damage.

The authors of this study investigated task switching following cerebellar damage. The study group consisted of 7 children and adolescents (M age = 13.8 years) who underwent surgical removal of a benign posterior fossa tumor. They were tested at a sufficient interval after surgery (M lag = 6.13 years) for restoration of normal cognitive skills and intelligence. Although all showed normal learning of the task compared with control participants, when rapid behavioral changes were required (short preparation time), they exhibited behavioral rigidity manifested by enhanced switching cost. These results are in line with another study on serial reaction time with the same patients (A. Berger et al., in press). They have important implications for our understanding of the cognitive sequelae of early cerebellar damage as well as the involvement of the cerebellum in task switching. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Analysis of adhesive interface in root canals irradiated by Er,Cr:YSGG laser after luting a fiber post

This study evaluated the effect of Er,Cr:YSGG laser on the root canal dentin after luting a fiber post. Twenty‐four bovine teeth roots were prepared using NiTi instruments and filled with Sealer 26 and gutta‐percha. Post spaces were prepared and roots were distributed according to dentin treatment (n = 8): 2.5%NaOCl (group control), Er,Cr:YSGG laser (1.5 W, 20 Hz, 20 s) (group test 1) or 2.5%NaOCl + Er,Cr:YSGG laser (group test 2). Fiber posts were luted using adhesive cement (Rely X U200, 3M) and roots were prepared to confocal laser scanning microscopy (CLSM) and scanning electron microscope (SEM). The morphology of interface, thickness of cement, and the gaps and tags were analyzed. Non‐parametrical data for thickness of cement were submitted to Friedman and Kruskall–Wallis tests (α = 0.05) and parametrical data for gaps to ANOVA (α = 0.05). CLSM of the cement thickness and gaps revealed no significant difference in surface treatment (NaOCl, Er,Cr:YSGG laser and NaOCl + Er,Cr:YSGG laser) (p > .05) and canal thirds (cervical, middle, and apical) (p > 0.05). SEM showed tags and a residual layer of cement adhered to dentin, mainly in laser‐irradiated specimens. The pretreatment of root canal with Er,Cr:YSGG laser previously to luting the fiber post with a self‐adhesive cement did not influence the cement thickness and gaps but affected the dentin interaction.     

Mental organization of maps.

Previous studies deconfounding spatial and temporal proximity during map learning have found a temporal influence on mental map organization. The authors explored whether this observed priming effect reflected the manner in which a map was learned by having people either name objects or point to them during learning. Naming objects resulted in temporal organization but pointing to objects resulted in spatial organization, suggesting that mental map organization is sensitive to emphasizing different types of map information during learning. The authors also explored whether the temporal organization observed in the naming group was influenced by the ease of using spatial information during learning, such as when the expectancy to use spatial information was made explicit or when a consistent temporal order was absent. When naming map objects, evidence for a spatial organization was weak, whereas a temporal organization was observed when a consistent temporal order was present. (PsycINFO Database Record (c) 2010 APA, all rights reserved)