Probabilistic-based discrete model for the seismic fragility assessment of masonry structures

Classical Finite-Element and Discrete-Element strategies are expensive to carry when analysing masonry structures in the inelastic range, under a seismic excitation, and considering uncertainty. Their application to the seismic fragility assessment of masonry structures through non-linear time-history analysis becomes thus a challenge. The paper addresses such difficulty by presenting an alternative probabilistic-based numerical strategy. The strategy couples a discrete macro-element model at a structural-scale with a homogenization model at a meso-scale. A probabilistic nature is guaranteed through a forward propagation of uncertainty through loading, material, mechanical, and geometrical parameters. An incremental dynamic analysis is adopted, in which several assumptions decrease the required computational time-costs. A random mechanical response of masonry is provided by numerical homogenization, using Latin hypercube sampling with a non-identity correlation matrix, and only a reduced number of representative random samples are transferred to the macro-scale. The approach was applied to the seismic fragility assessment of an English-bond masonry mock-up. Its effectiveness was demonstrated, and its computational attractiveness highlighted. Results may foster its use within the seismic fragility assessment of larger structures, and the opportunity to better analyze the effect of material and geometric-based uncertainties in the stochastic dynamic response of masonry structures.- (undefined

Superconductivity from spin fluctuations and long-range interactions in magic-angle twisted bilayer graphene

Magic-angle twisted bilayer graphene (MATBG) has been extensively explored both theoretically and experimentally as a suitable platform for a rich and tunable phase diagram that includes ferromagnetism, charge order, broken symmetries, and unconventional superconductivity. In this work, we investigate the intricate interplay between long-range electron-electron interactions, spin fluctuations, and superconductivity in MATBG. By employing a low-energy model for MATBG that captures the correct shape of the flat bands, we explore the effects of short- and long-range interactions on spin fluctuations and their impact on the superconducting (SC) pairing vertex in the Random Phase Approximation (RPA). We find that the SC state is notably influenced by the strength of long-range Coulomb interactions. Interestingly, our RPA calculations indicate that there is a regime where the system can traverse from a magnetic phase to the SC phase by \emph{increasing} the relative strength of long-range interactions compared to the on-site ones. These findings underscore the relevance of electron-electron interactions in shaping the intriguing properties of MATBG and offer a pathway for designing and controlling its SC phase.Comment: 9 pages, 5 figure

SLaMA-URM method for the seismic vulnerability assessment of UnReinforced Masonry structures: Formulation and validation for a substructure

An analytical procedure based on the SLaMA (Simplified Lateral Mechanism Analysis) method is proposed for the seismic vulnerability assessment of UnReinforced Masonry (URM) structures. The procedure considers an equivalent frame discretization for the structure (pier, spandrel, and joint elements) and includes: (i) the evaluation of moment‒rotation capacity curves at each pier-spandrel subassembly; (ii) the assessment of the hierarchy of strength in each subassembly; and (iii) the calculation of the structure capacity curve according to the expected failure mechanism. Validation of the proposed SLaMA-URM procedure is achieved in a one-story URM substructure tested under lateral cyclic loading. The analytical predictions are compared with numerical ones from a 2D continuous finite element (FE) model based on a macro-modelling strategy. The flexural capacity of the components is estimated using a monolithic beam analogy, and the results compared with those from traditional sectional analysis. The influence of the substructure geometry on the hierarchy of strength at the subassembly and global levels is investigated. An analytical formulation of the pier-spandrel joint strength is also proposed to be considered in the assessment of the hierarchy of strength. The method is validated for a one-story substructure subjected to lateral in-plane loading. Results, in terms of crack patterns and capacity curves, are in relatively good agreement with the experimental and FE results, even when a bilinear curve approximation is used. The potential of the SLaMA-URM method for the seismic assessment of URM buildings is demonstrated, whose application to a larger URM structure is planned as a subsequent study

A barrier for further approximating Sorting By Transpositions

The Transposition Distance Problem (TDP) is a classical problem in genome rearrangements which seeks to determine the minimum number of transpositions needed to transform a linear chromosome into another represented by the permutations $\pi$ and $\sigma$, respectively. This paper focuses on the equivalent problem of Sorting By Transpositions (SBT), where $\sigma$ is the identity permutation $\iota$. Specifically, we investigate palisades, a family of permutations that are "hard" to sort, as they require numerous transpositions above the celebrated lower bound devised by Bafna and Pevzner. By determining the transposition distance of palisades, we were able to provide the exact transposition diameter for $3$-permutations (TD3), a special subset of the Symmetric Group $S_n$, essential for the study of approximate solutions for SBT using the simplification technique. The exact value for TD3 has remained unknown since Elias and Hartman showed an upper bound for it. Another consequence of determining the transposition distance of palisades is that, using as lower bound the one by Bafna and Pevzner, it is impossible to guarantee approximation ratios lower than $1.375$ when approximating SBT. This finding has significant implications for the study of SBT, as this problem has been subject of intense research efforts for the past 25 years

The applications of cold atmospheric plasma in dentistry

ACKNOWLEDGMENTSNeusa Silva sincerely acknowledges Fundação para aCiência e a Tecnologia (FCT) for the PhD Scholarship—Cold Atmospheric Plasma for periodontal and peri‐implant disease treatment: antibacterial effects andcellular response, 2022. 13655. BD. The authors alsothank the research center Grants N°. UIDP/FIS/04559/2020 (LIBPhys), from FCT, Portugal.Cold atmospheric plasma (CAP), as a noninvasive technology, has shown promise in dentistry as it might successfully treat various oral conditions. The antimicrobial capacity of CAP has been proven and it is effective in reducing the main microorganisms responsible for oral infections. Furthermore, CAP has also been explored in the field of tissue regeneration with a great response from both soft and hard tissue. The surface modification ability of CAP is another area of interest, revealing a potential improvement in the osseointegration of dental implants. Additionally, there are other areas within dentistry that have studied the use of CAP, such as surface disinfection, bleaching, and cavity preparation.info:eu-repo/semantics/publishedVersio

Measured data of Drosophila melanogaster (Diptera Drosophilidae) development and learning and memory behaviour after copper exposition

This article presents the statistical analysis data from Drosophila melanogaster development (from larvae to adult) and learning and memory retention behavior of a Pavlovian conditioning in male and female flies exposed to copper. While the full data sets are available In the article: Copper decrease associative learning and memory in D. melanogaster, this data-in-brief article includes the detailed statistical analysis performed. Data demonstrates Statistica Software analysis between the subject part of the analysis: 2 treatments x 2 sexes x 2 ages and within subject part of the analysis: 2 treatments x 2 sex x 2 ages x 4 times, repeated measures

Species pool structure determines the level of generalism of island parasitoid faunas

Copyright © 2011 Blackwell Publishing Ltd.AIM To examine whether island parasitoid faunas are biased towards generalists when compared with the mainland and their species pool, and to evaluate the effects of climate, island characteristics and regional factors on the relative proportions of idiobionts (i.e. generalists) and koinobionts (i.e. specialists) of two parasitic wasp families, Braconidae and Ichneumonidae. LOCATION Seventy-three archipelagos distributed world-wide. METHODS We used data on the distribution and biology obtained from a digital catalogue and several literature sources. We related level of generalism, measured as the ratio between the number of idiobiont and koinobiont species, to climatic, physiographic and regional factors using generalized linear models. We compared models by means of Akaike weighting, and evaluated the spatial structure of their residuals. We used partial regressions to determine whether the final models account for all latitudinal structure in the level of generalism. RESULTS Islands host comparatively more idiobionts than continental areas. Although there is a latitudinal gradient in the level of generalism of island faunas correlating with both environmental factors and island characteristics, the most important determinant of island community structure is their source pool. This effect is stronger for ichneumonids, where generalism is higher in the Indomalayan region, arguably due to the higher diversity of endophytic hosts in its large rain forests. MAIN CONCLUSIONS The level of generalism of island parasitoid faunas is largely constrained by regional factors, namely by the structure of the species pool, which emphasizes the importance of including regional processes in our understanding of the functioning of ecological communities. The fact that generalist species are more predominant in islands with a large cover of rain forests pinpoints the importance of the indirect effects of ecological requirements on community structure, highlighting the complex nature of geographical gradients of diversity

Seismic assessment of unreinforced masonry structures: a coupled mesoscale-DMEM approach

A numerical investigation is performed to investigate the potential of a discrete macro-element coupled with a mesoscale approach for the seismic assessment of unreinforced masonry structures. At first, parametric analyses are performed on a U-shape stone masonry prototype. Nonlinear static analyses are performed to investigate parameters that affect the results when a mesoscale masonry pattern representation is adopted. Results prove the suitability of a mesoscale representation of unreinforced masonry structures through a discrete macro-element approach. Furhthermore, it is demonstrated that an irregular placement of masonry units’ have a significant role in the structural response, either from a strength and ductility standpoints, when compared to a regular and periodic distribution of units