Seismic motion in urban sites consisting of blocks in welded contact with a soft layer overlying a hard half space: I. Finite set of blocks

We address the problem of the response to a seismic wave of an urban site consisting of $N$ non-identical, non-equispaced blocks overlying a soft layer underlain by a hard substratum. The results of a theoretical analysis, appealing to a space-frequency mode-matching (MM) technique, are compared to those obtained by a space-time finite element (FE) technique. The two methods are shown to give rise to the same prediction of the seismic response for N=1 and N=2 blocks. The mechanism of the interaction between blocks and the ground, as well as that of the mutual interaction between blocks, are studied. It is shown that the presence of a small number of blocks modifies the seismic disturbance in a manner which evokes qualitatively, but not quantitatively, what was observed during the 1985 Michoacan earthquake in Mexico City. Disturbances at a much greater level, induced by a large number of blocks (in fact, a periodic set) are studied in the companion paper.Comment: submitted to Geophys.J.Int

A tetrameric inhibitor of insect α-amylase from barley

A tetrameric inhibitor that is active against α-amylase from the larvae of the insect Tenebrio molitor, but inactive against the enzyme from human saliva and against the endogenous one, has been described in barley endosperm. The subunits of the inhibitor have been identified as the previously characterized proteins CMa, CMb and CMd, of which only CMa was inhibitory by itself

Imaging the Kirkendall effect in pyrite (FeS2) thin films: cross-sectional microstructure and chemical features

This investigation provides novel data on the structure and chemical composition of pyrite thin films and new hints concerning their formation mechanism. From TEM-HAADF data, it has been found that the films are composed of two different layers: one is very compact and the other one is quite porous with many voids separating a few groups of grains. This porous layer is always in direct contact with the substrate, and its thickness is quite similar to that of the original Fe film. The average size of pyrite grains is equal in both layers, what suggests that the same process is responsible for their formation. Concentration profiles of sulfur, iron and some impurities (mainly sodium and oxygen from the glass substrate) through both layers are given in this work, and thus chemical inhomogeneities of the films are proved by the obtained stoichiometric ratios (S/Fe). Moreover, Na from sodalime glass substrates mainly accumulates at the pyrite grain boundaries and barely dopes them. The obtained results support the hypothesis that the iron sulfuration process essentially induces the diffusion of iron atoms, what leads to the porous layer formation as a manifestation of the Kirkendall Effect. Therefore, it seems that the same mechanisms that operate in the synthesis of surface hollow structures at the nanoscale are also active in the formation of pyrite thin films ranging from several tens to hundreds of nanometersMembers of MIRE Group acknowledge the financial support of the Spanish MICINN under project RTI2018-099794-B-I00. E. Flores acknowledges the intramural CSIC project 2D-MeSes funding and the service from the MiNa Laboratory at IMN, and funding from CM (project SpaceTec, S2013/ICE2822), MINECO (project CSIC13-4E1794) and EU (FEDER,FSE). Financial support through the project UMA18-FEDERJA-041 is gratefully acknowledge

Community-based screening of Chagas disease among Latin American migrants in a non-endemic country: an observational study

Background: Chagas disease is a parasitic disease endemic to Latin America, but it has become a disease of global concern due to migration flows. Asymptomatic carriers may host the parasite for years, without knowing they are infected. The aim of this study is to assess prevalence of Chagas disease and evaluate the participants' level of knowledge between Latin American migrants attending a community-based screening campaign. Methods: Three community-based campaigns were performed in Alicante (Spain) in 2016, 2017 and 2018, including educational chats and blood tests for Trypanosoma cruzi serology. Participants completed a questionnaire assessing knowledge about the mechanisms of transmission, disease presentation, diagnosis, and treatment. People seropositive for T. cruzi underwent diagnostic confirmation by two different tests. Results were analyzed by multivariable logistic regression and expressed as adjusted odds ratios (aORs), adjusting for age, sex, and time in Spain. Results: A total of 596 participants were included in the study; 17% were aged under 18 years. Prevalence in adults was 11% [54/496; 95% confidence interval (CI): 8.3-14.5%] versus 0% among children. All but one case were in Bolivians. Diagnosis was independently associated with having been born in Bolivia (aOR: 102, 95% CI: 13-781) and a primary school-level education (aOR: 2.40, 95% CI: 1.14-5.06). Of 54 people diagnosed with Chagas disease (most of whom were asymptomatic), 42 (77.7%) returned to the clinic at least once, and 24 (44.4%) received treatment. Multivariable analysis showed that coming from Argentina (aOR: 13, 95% CI: 1.61-1188) or Bolivia (aOR: 1.90, 95% CI: 1.19-3.39) and having received information about Chagas disease in Spain (aOR: 4.63, 95% CI: 2.54-8.97) were associated with a good level of knowledge on the disease. Having primary level studies (aOR: 0.59, 95% CI: 0.34-0.98) and coming from Ecuador (aOR: 4.63, 95% CI: 2.52-847) were independently associated with a lower level of knowledge. Conclusions: Community-based interventions are a good strategy for diagnosing neglected diseases such as Chagas disease in non-endemic countries and for identifying and treating infected, asymptomatic individuals.This study was partially supported by the third call for research grants (J-M.R.-R.) from the Institute of Health and Biomedical Research of Alicante (ISABIAL)/FISABIO Foundation (III convocatoria de ayudas a proyectos de investigación del Instituto de Investigación Sanitaria y Biomédica de Alicante (ISABIAL) – Fundación FISABIO) (UGP-16-158); and by the collaborative agreement between ISABIAL/Fundación FISABIO and Fundación Mundo Sano-Spain, in accordance with the Sponsorship Law. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.S