3,776 research outputs found

    Microscopic nanomechanical dissipation in gallium arsenide resonators

    Full text link
    We report on a systematic study of nanomechanical dissipation in high-frequency (approximatively 300 MHz) gallium arsenide optomechanical disk resonators, in conditions where clamping and fluidic losses are negligible. Phonon-phonon interactions are shown to contribute with a loss background fading away at cryogenic temperatures (3 K). Atomic layer deposition of alumina at the surface modifies the quality factor of resonators, pointing towards the importance of surface dissipation. The temperature evolution is accurately fitted by two-level systems models, showing that nanomechanical dissipation in gallium arsenide resonators directly connects to their microscopic properties. Two-level systems, notably at surfaces, appear to rule the damping and fluctuations of such high-quality crystalline nanomechanical devices, at all temperatures from 3 to 300K

    Corporate social responsibility and its effect on earnings management: an empirical research on Spanish firms

    Get PDF
    The ethics of financial reporting assumes a centre stage in the corporate world in the background of an emerging understanding of Corporate Social Responsibility (CSR). The purpose of this paper is to investigate whether the CSR orientation of a firm affects its reporting incentives, in terms of the accrual-based earnings management. The main argument is that CSR induces transparency and reduces the propensity towards the number of opportunities for earnings management. Using archival data from a panel sample of 100 most reputable Spanish firms between 2011 and 2015, we find a negative impact of CSR practices on earnings management. The findings demonstrate the socially responsible firms are inclined to foster long–term relationships with stakeholders rather than maximise their short-term profit. In this regard, providing quality earnings is closely connected to CSR activities, especially in that both aim to meet the needs of the stakeholders. Our findings have important implications for shareholders, investors and analysts who may consider CSR as an expression of ‘ethical’ investing and a possible reflection of the quality of financial reporting. These groups should be very cautious in relying on CSR information for Spanish firm's analysis, since CSR is found to have significant impact on earnings management

    Extremophilic bacteria restrict the growth of Macrophomina phaseolina by combined secretion of polyamines and lytic enzymes

    Get PDF
    [EN] Extremophilic microorganisms were screened as biocontrol agents against two strains of Macrophomina phaseolina (Mp02 and 06). Stenotrophomonas sp. AG3 and Exiguobacterium sp. S58 exhibited a potential in vitro antifungal effect on Mp02 growth, corresponding to 52.2% and 40.7% inhibition, respectively. This effect was confirmed by scanning electron microscopy, where images revealed marked morphological alterations in fungus hyphae. The bacteria were found to secrete lytic enzymes and polyamines. Exiguobacterium sp. S56a was the only strain able to reduce the growth of the two strains of M. phaseolina through their supernatant. Antifungal supernatant activity was correlated with the ability of bacteria to synthesize and excrete putrescine, and the exogenous application of this polyamine to the medium phenocopied the bacterial antifungal effects. We propose that the combined secretion of putrescine, spermidine, and lytic enzymes by extremophilic microorganism predispose these microorganisms to reduce the disease severity occasioned by M. phaseolina in soybean seedlings.The authors acknowledge the generous financial support by the PICT V Bicentenario 2010 1788 Project (FONCyT, Argentina). This work was performed in the context of a project called ¿Análisis de Adaptación al Cambio Climático en Humedales Andinos¿. ID: 6188775¿8-LP13. Ministerio del Medio Ambiente, Región de Antofagasta. We are also grateful to Lic. C. Pérez Brandan for providing us with the M. phaseolina strains used in this study.Santos, AP.; Nieva Muratore, L.; Sole-Gil, A.; Farías, ME.; Ferrando Monleón, AR.; Blazquez Rodriguez, MA.; Belfiore, C. (2021). Extremophilic bacteria restrict the growth of Macrophomina phaseolina by combined secretion of polyamines and lytic enzymes. Plant Biotechnology Reports. 32:1-9. https://doi.org/10.1016/j.btre.2021.e00674S193

    Mismatch repair SNPs and thyroid cancer susceptibility: a potential role for the MSH6 rs1042821 (Gly39Glu) polymorphism

    Get PDF
    Abstract of the Poster presented at the 3rd ESPT Conference (European Society of Pharmacogenomics and Personalised Therapy / European Society of Pharmacogenomics and Theranostics), 7-9 October 2015, Budapest

    SIOSE Andalucía, experiencia de integración y actualización de bases cartográficas multiescala

    Get PDF
    El objetivo de SIOSE en Andalucía ha sido la obtención de una base cartográfica de referencia a escala de detalle 1:10.000, escalable a 1:25.000, donde se sintetizan e integran tanto la información geométrica como la temática de cartografías ya existentes (usos del territorio, SIGPAC, coberturas del suelo, información de comunidades fitosociológicas, redes de comunicación, superficies húmedas, red hidrográfica, zonas de extracción, balsas, entramado urbano, etc.) siguiendo un protocolo establecido para, posteriormente, actualizarla al año de referencia mediante fotointerpretación. La integración de las diferentes cartografías se fundamentó en la definición de unos valores mínimos de tolerancia, tanto de distancia entre líneas como de tamaño mínimo de superficie en función del uso asignado al polígono. La generación de la cartografía a escala 1:25.000 se llevó a cabo a través de procesos automáticos de cambio de modelo de datos, cambio de escala y eliminación de pasillos. La inquietud de abordar la experiencia de SIOSE-Andalucía nace de la necesidad detectada desde hace tiempo de tener una base de referencia que combine parámetros bióticos con elementos administrativos y el parcelario de la propiedad.The aim of SIOSE in Andalucía has been obtaining a detailed scale 1:10.000 cartographic database of reference, scalable to 1:25.000, where geometry and also thematic information of existing cartographies have been combined and joined (land uses, SIGPAC, land covers, phytosociological plant communities, communication network, humid areas, hydrographic network, extraction zones, irrigation pools, urban network, etc.) following an established protocol for, afterwards, updating the cartography to the referred year using photo-interpretation. The integration of different cartographies is based on the definition of minimum values of tolerance for the distance between lines as well as minimum sizes of area, depending on the assigned land use to each polygon. The production of cartography 1:25.000 was carried out through automatic processes of data model converter, scale change and elimination of narrowing polygons. The interest of tackling the experience of SIOSE-Andalucia is sprung from the detected necessity of having a resource which combines biotic parameters with administrative elements and property divisions

    PREVALENCE OF INTESTINAL PARASITISM AND ASSOCIATED SYMPTOMATOLOGY AMONG HEMODIALYSIS PATIENTS

    Get PDF
    ;Intestinal parasites are an important cause of morbidity and mortality. Immunocompromised individuals may develop more severe forms of these infections. Taking into account the immunity impairment in patients suffering from chronic renal failure (CRF), we will determine the prevalence and associated symptoms of intestinal parasites in these patients. Controls without CRF were used for comparison. Stool samples were collected and processed for microscopic identification of parasites using the Formalin-ether concentration method. For Cryptosporidium diagnosis, the ELISA technique was used. One hundred and ten fecal samples from hemodialysis patients were analyzed, as well as 86 from a community group used as control group. A result of 51.6% of intestinal parasites was observed in hemodialysis patients and 61.6% in the control group. Cryptosporidium and Blastocystis were the most common infections in patients with CRF (26.4% and 24.5%, respectively). Blastocystis was the most common infection in the control group (41.9%), however no individual was found positive for Cryptosporidium. Among the CRF patients, 73.6% were symptomatic, 54.3% of these tested positive for at least one parasite, in contrast to 44.8% in asymptomatic patients (p = 0.38). The most common symptoms in this group were flatulence (36.4%), asthenia (30.0%) and weight loss (30.0%). In the control group, 91.9% were symptomatic, 60.8% of these tested positive for at least one parasite, in contrast to 71.4% in asymptomatic patients (p = 0.703). A significant difference between the two groups was observed with regard to symptoms, with bloating, postprandial fullness, and abdominal pain being more frequent in the control group than in the hemodialysis group (all p < 0.05). Comparing symptomatic with asymptomatic, there was no association in either group between symptoms or the prevalence of parasitic infection, nor with the type of parasite or with multiple parasitic infections. Patients with chronic renal failure are frequent targets for renal transplantation, which as well as the inherent immunological impairment of the disease itself, results in immunosuppression by medication. For this reason, carriers of intestinal parasites with pathogenic potential can develop serious clinical complications influencing the success of transplantation. This fact, coupled with the high prevalence of intestinal parasites and the dissociation between symptoms and infection in CRF patients, suggests that the stool test should be incorporated in routine propedeutics. Furthermore, preventive measures for the acquisition of parasites through the fecal-oral contamination route should be introduced.Doenças parasitárias infectam grande número de indivíduos em todo o mundo. Manifestações clínicas mais severas podem se apresentar em pacientes imunocomprometidos. Considerando o importante comprometimento imunológico observado em pacientes com insuficiência renal crônica (IRC), foi determinada a prevalência e sintomas associados a parasitoses intestinais nesses pacientes em comparação a controles saudáveis. Foram coletadas amostras fecais de cada participante e processadas para identificação microscópica dos parasitas pelo método de concentração por formol-éter. Foi utilizada a técnica de ELISA para identificar coproantígenos de Cryptosporidium. Foram analisadas 110 amostras fecais de pacientes em hemodiálise e 86 de um grupo controle comunitário. Cryptosporidium e Blastocystis foram as infecções mais freqüentes nos pacientes em hemodiálise (26,4% e 24,5%, respectivamente). Blastocystis foi a infecção mais freqüente no grupo controle (41,9%), entretanto nenhum indivíduo positivo para Cryptosporidium foi identificado. Considerando os pacientes com IRC, 73,6% eram sintomáticos, sendo 54,3% positivos para algum parasita, contra 44,8% nos assintomáticos (p = 0,38). Os sintomas mais frequentes neste grupo foram flatulência (36,4%), adinamia (30,0%) e perda de peso (30,0%). No grupo controle, 91,9% eram sintomáticos, sendo 60,8% positivos para algum parasita, contra 71,4% nos assintomáticos (p = 0,703). Em relação aos sintomas, houve diferença significativa entre os dois grupos, sendo que flatulência, plenitude pós-prandial, e dor abdominal foram mais freqüentes no grupo controle que nos pacientes em hemodiálise (todos p < 0,05). Comparando-se sintomáticos com assintomáticos, não houve associação entre a sintomatologia e a prevalência de parasitose, nem com o tipo de parasita, e nem com o poliparasitismo, nos dois grupos. Considerando que pacientes com IRC são frequentes alvos de transplante renal, resultando em imunossupressão por medicamentos, que é somada à deficiência imunológica inerente à própria doença. Os portadores de parasitas intestinais com potencial patogênico podem desenvolver sérias complicações clínicas que influenciam o sucesso do transplante. Este fato, aliado a alta prevalência de parasitas intestinais e dissociação entre os sintomas e infecção nesses pacientes, sugerem a incorporação do exame de fezes na propedêutica de rotina dos mesmos, juntamente com medidas preventivas para a aquisição de parasitas com rota de contaminação fecal-oral

    Mechano-Optical Analysis of Single Cells with Transparent Microcapillary Resonators

    Get PDF
    The study of biophysical properties of single cells is becoming increasingly relevant in cell biology and pathology. The measurement and tracking of magnitudes such as cell stiffness, morphology, and mass or refractive index have brought otherwise inaccessible knowledge about cell physiology, as well as innovative methods for high-throughput label-free cell classification. In this work, we present hollow resonator devices based on suspended glass microcapillaries for the simultaneous measurement of single-cell buoyant mass and reflectivity with a throughput of 300 cells/minute. In the experimental methodology presented here, both magnitudes are extracted from the devices' response to a single probe, a focused laser beam that enables simultaneous readout of changes in resonance frequency and reflected optical power of the devices as cells flow within them. Through its application to MCF-7 human breast adenocarcinoma cells and MCF-10A nontumorigenic cells, we demonstrate that this mechano-optical technique can successfully discriminate pathological from healthy cells of the same tissue type
    corecore