229 research outputs found

    Influencia del Porcentaje de SiCp en el Comportamiento a la Corrosión de la Aleación AA6061 Obtenida por Compactación Isostática

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    Se ha estudiado el comportamiento a la corrosión de materiales compuestos A6061/SiCp obtenidos por compactación isostática y extrusión en caliente de polvos mediante ensayos de polarización cíclica. El estudio de la naturaleza de los productos de corrosión se ha llevado a cabo mediante Microscopía Electrónica de Barrido (SEM) después de la realización de los ensayos, con objeto de estudiar la influencia de la proporción de refuerzo en el comportamiento a la corrosión. El proceso de corrosión está significativamente influenciado por la adición de partículas reforzantes, debido a que las intercaras matriz/SiCp son centros preferentes de ataque localizado por picadura

    Hill's Equation with Random Forcing Parameters: Determination of Growth Rates through Random Matrices

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    This paper derives expressions for the growth rates for the random 2 x 2 matrices that result from solutions to the random Hill's equation. The parameters that appear in Hill's equation include the forcing strength and oscillation frequency. The development of the solutions to this periodic differential equation can be described by a discrete map, where the matrix elements are given by the principal solutions for each cycle. Variations in the forcing strength and oscillation frequency lead to matrix elements that vary from cycle to cycle. This paper presents an analysis of the growth rates including cases where all of the cycles are highly unstable, where some cycles are near the stability border, and where the map would be stable in the absence of fluctuations. For all of these regimes, we provide expressions for the growth rates of the matrices that describe the solutions.Comment: 22 pages, 3 figure

    Towards equity and justice in ocean sciences

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    This is the final version. Available on open access from Nature Research via the DOI in this recordData availability; All data needed to evaluate the conclusions in the paper are present in the paper.The global scientific community is currently going through a self-reckoning in which it is questioning and re-examining its existing practices, many of which are based on colonial and neo-colonial perceptions. This is particularly acute for the ocean research community, where unequal and unbalanced international collaborations have been rife. Consequently, numerous discussions and calls have been made to change the current status quo by developing guidelines and frameworks addressing the key issues plaguing our community. Here, we provide an overview of the key topics and issues that the scientific community has debated over the last three to four years, with an emphasis on ocean research, coupled with actions per stakeholder groups (research community, institutions, funding agencies, and publishers). We also outline some key discussions that are currently missing and suggest a path forward to tackle these gaps. We hope this contribution will further accelerate efforts to bring more equity and justice into ocean sciences.Schmidt Foundatio

    Moving conferences online: lessons learned from an international virtual meeting

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    We consider the opportunities and challenges associated with organizing a conference online, using a case study of a medium-sized (approx. 400 participants) international conference held virtually in August 2020. In addition, we present quantifiable evidence of the participants' experience using the results from an online post-conference questionnaire. Although the virtual meeting was not able to replicate the in-person experience in some aspects (e.g. less engagement between participants) the overwhelming majority of respondents found the meeting an enjoyable experience and would join similar events again. Notably, there was a strong desire for future in-person meetings to have at least some online component. Online attendance by lower-income researchers was higher compared with a past, similar-themed in-person meeting held in a high-income nation, but comparable to one held in an upper-middle-income nation. This indicates that online conferences are not a panacea for diversity and inclusivity, and that holding in-person meetings in developing economies can be at least as effective. Given that it is now relatively easy to stream contents of meetings online using low-cost methods, there are clear benefits in making all presented content accessible online, as well as organizing online networking events for those unable to attend in person

    Moving conferences online: lessons learned from an international virtual meeting

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    We consider the opportunities and challenges associated with organizing a conference online, using a case study of a medium-sized (approx. 400 participants) international conference held virtually in August 2020. In addition, we present quantifiable evidence of the participants’ experience using the results from an online post-conference questionnaire. Although the virtual meeting was not able to replicate the in-person experience in some aspects (e.g. less engagement between participants) the overwhelming majority of respondents found the meeting an enjoyable experience and would join similar events again. Notably, there was a strong desire for future inperson meetings to have at least some online component. Online attendance by lower-income researchers was higher compared with a past, similarthemed in-person meeting held in a high-income nation, but comparable to one held in an upper-middle-income nation. This indicates that online conferences are not a panacea for diversity and inclusivity, and that holding in-person meetings in developing economies can be at least as effective. Given that it is now relatively easy to stream contents of meetings online using low-cost methods, there are clear benefits in making all presented content accessible online, as well as organizing online networking events for those unable to attend in person

    Analysis and Verification of Service Interaction Protocols - A Brief Survey

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    Modeling and analysis of interactions among services is a crucial issue in Service-Oriented Computing. Composing Web services is a complicated task which requires techniques and tools to verify that the new system will behave correctly. In this paper, we first overview some formal models proposed in the literature to describe services. Second, we give a brief survey of verification techniques that can be used to analyse services and their interaction. Last, we focus on the realizability and conformance of choreographies.Comment: In Proceedings TAV-WEB 2010, arXiv:1009.330

    Association of Aortic Stiffness With Biomarkers of Neuroinflammation, Synaptic Dysfunction, and Neurodegeneration

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    OBJECTIVES: To test the hypothesis that increased aortic stiffening is associated with greater cerebrospinal fluid (CSF) evidence of core Alzheimer's disease pathology (Aβ, phosphorylated tau (p-tau)), neurodegeneration (total tau (t-tau)), synaptic dysfunction (neurogranin), neuroaxonal injury (neurofilament light (NFL)), and neuroinflammation (YKL-40, sTREM2), we analyzed pulse wave velocity (PWV) data and CSF data among older adults. METHODS: Participants free of stroke and dementia from the Vanderbilt Memory and Aging Project, an observational community-based study, underwent cardiac magnetic resonance to assess aortic pulse wave velocity (PWV, m/sec) and lumbar puncture to obtain CSF. Linear regressions related aortic PWV to CSF Aβ, p-tau, t-tau, neurogranin, NFL, YKL-40, and sTREM2 concentrations adjusting for age, race/ethnicity, education, apolipoprotein (APOE) ε4 status, Framingham Stroke Risk Profile, and cognitive diagnosis. Models were repeated testing PWV interactions with age, diagnosis, APOE-ε4, and hypertension on each biomarker. RESULTS: 146 participants were examined (72±6 years). Aortic PWV interacted with age on p-tau (β=0.31, p=0.04), t-tau, (β=2.67, p=0.05), neurogranin (β=0.94, p=0.04), and sTREM2 (β=20.4, p=0.05). Among participants over age 73 years, higher aortic PWV related to higher p-tau (β=2.4, p=0.03), t-tau (β=19.3, p=0.05), neurogranin (β=8.4, p=0.01), and YKL-40 concentrations (β=7880, p=0.005). Aortic PWV had modest interactions with diagnosis on neurogranin (β=-10.76, p=0.03) and hypertension status on YKL-40 (β=-18020, p<0.001). CONCLUSIONS: Among our oldest participants, age 74 years and older, greater aortic stiffening is associated with in vivo biomarker evidence of neuroinflammation, tau phosphorylation, synaptic dysfunction, and neurodegeneration, but not amyloidosis. Central arterial stiffening may lead to cumulative cerebral microcirculatory damage and blood flow delivery to tissue, resulting in neuroinflammation and neurodegeneration in more advanced age

    Assessment of Multilocus Sequence Analysis (MLSA) for Identification of Candidatus Liberibacter Solanacearum from Different Host Plants in Spain

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    [EN] Liberibacteris a bacterial group causing different diseases and disorders in plants. Among liberibacters,CandidatusLiberibacter solanaceraum (CLso) produces disorders in several species mainly within Apiaceae and Solanaceae families. CLso isolates are usually grouped in defined haplotypes according to single nucleotide polymorphisms in genes associated with ribosomal elements. In order to characterize more precisely isolates of CLso identified in potato in Spain, a Multilocus Sequence Analysis (MLSA) was applied. This methodology was validated by a complete analysis of ten housekeeping genes that showed an absence of positive selection and a nearly neutral mechanism for their evolution. Most of the analysis performed with single housekeeping genes, as well as MLSA, grouped together isolates of CLso detected in potato crops in Spain within the haplotype E, undistinguishable from those infecting carrots, parsnips or celery. Moreover, the information from these housekeeping genes was used to estimate the evolutionary divergence among the different CLso by using the concatenated sequences of the genes assayed. Data obtained on the divergence among CLso haplotypes support the hypothesis of evolutionary events connected with different hosts, in different geographic areas, and possibly associated with different vectors. Our results demonstrate the absence in Spain of CLso isolates molecularly classified as haplotypes A and B, traditionally considered causal agents of zebra chip in potato, as well as the uncertain possibility of the present haplotype to produce major disease outbreaks in potato that may depend on many factors that should be further evaluated in future worksThis research was funded by Instituto Nacional de Investigacion y Tecnologia Agraria y Alimentaria (INIA), grant numbers AT2016-007 and RTA2014-00008-C04-03-E, co-financed by FEDER.Ruiz-Padilla, A.; Redondo, C.; Asensio, A.; Garita-Cambronero, J.; Martinez, C.; Perez-Padilla, V.; Marquinez, R.... (2020). Assessment of Multilocus Sequence Analysis (MLSA) for Identification of Candidatus Liberibacter Solanacearum from Different Host Plants in Spain. Microorganisms. 8(9):1-19. https://doi.org/10.3390/microorganisms8091446S11989Haapalainen, M. (2014). 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Complete genome sequence of Liberibacter crescens BT-1. Standards in Genomic Sciences, 7(2), 271-283. doi:10.4056/sigs.3326772Teresani, G. R., Bertolini, E., Alfaro-Fernández, A., Martínez, C., Tanaka, F. A. O., Kitajima, E. W., … Font, M. I. (2014). Association of ‘Candidatus Liberibacter solanacearum’ with a Vegetative Disorder of Celery in Spain and Development of a Real-Time PCR Method for Its Detection. Phytopathology®, 104(8), 804-811. doi:10.1094/phyto-07-13-0182-rLi, W., Hartung, J. S., & Levy, L. (2006). Quantitative real-time PCR for detection and identification of Candidatus Liberibacter species associated with citrus huanglongbing. Journal of Microbiological Methods, 66(1), 104-115. doi:10.1016/j.mimet.2005.10.018Munyaneza, J. E., Sengoda, V. G., Crosslin, J. M., De la Rosa-Lozano, G., & Sanchez, A. (2009). First Report of ‘Candidatus Liberibacter psyllaurous’ in Potato Tubers with Zebra Chip Disease in Mexico. 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Assessment of MultiLocus Sequence Analysis As a Valuable Tool for the Classification of the Genus Salinivibrio. Frontiers in Microbiology, 8. doi:10.3389/fmicb.2017.01107Hajri, A., Loiseau, M., Cousseau-Suhard, P., Renaudin, I., & Gentit, P. (2017). Genetic Characterization of ‘Candidatus Liberibacter solanacearum’ Haplotypes Associated with Apiaceous Crops in France. Plant Disease, 101(8), 1383-1390. doi:10.1094/pdis-11-16-1686-reFang, Y., Wang, Y., Liu, Z., Dai, H., Cai, H., Li, Z., … Wang, D. (2019). Multilocus Sequence Analysis, a Rapid and Accurate Tool for Taxonomic Classification, Evolutionary Relationship Determination, and Population Biology Studies of the Genus Shewanella. Applied and Environmental Microbiology, 85(11). doi:10.1128/aem.03126-18Konstantinidis, K. T., Ramette, A., & Tiedje, J. M. (2006). Toward a More Robust Assessment of IntraspeciesDiversity, Using Fewer GeneticMarkers. Applied and Environmental Microbiology, 72(11), 7286-7293. doi:10.1128/aem.01398-06Ajene, I. J., Khamis, F., Ballo, S., Pietersen, G., van Asch, B., Seid, N., … Mohamed, S. (2020). Detection of Asian Citrus Psyllid (Hemiptera: Psyllidae) in Ethiopia: A New Haplotype and its Implication to the Proliferation of Huanglongbing. Journal of Economic Entomology, 113(4), 1640-1647. doi:10.1093/jee/toaa113Thapa, S. P., De Francesco, A., Trinh, J., Gurung, F. B., Pang, Z., Vidalakis, G., … Coaker, G. (2020). Genome‐wide analyses of Liberibacter species provides insights into evolution, phylogenetic relationships, and virulence factors. Molecular Plant Pathology, 21(5), 716-731. doi:10.1111/mpp.12925Antolinez, C. A., Fereres, A., & Moreno, A. (2017). Risk assessment of ‘Candidatus Liberibacter solanacearum’ transmission by the psyllids Bactericera trigonica and B. tremblayi from Apiaceae crops to potato. Scientific Reports, 7(1). doi:10.1038/srep45534Antolínez, Moreno, Ontiveros, Pla, Plaza, Sanjuan, … Fereres. (2019). Seasonal Abundance of Psyllid Species on Carrots and Potato Crops in Spain. Insects, 10(9), 287. doi:10.3390/insects10090287Wang, J., Haapalainen, M., Schott, T., Thompson, S. M., Smith, G. R., Nissinen, A. I., & Pirhonen, M. (2017). Genomic sequence of «Candidatus Liberibacter solanacearum» haplotype C and its comparison with haplotype A and B genomes. PLOS ONE, 12(2), e0171531. doi:10.1371/journal.pone.0171531Katsir, L., Zhepu, R., Santos Garcia, D., Piasezky, A., Jiang, J., Sela, N., … Bahar, O. (2018). Genome Analysis of Haplotype D of Candidatus Liberibacter Solanacearum. Frontiers in Microbiology, 9. doi:10.3389/fmicb.2018.02933Quintana-González de Chaves, M., Teresani, G. R., Hernández-Suárez, E., Bertolini, E., Moreno, A., Fereres, A., … Siverio, F. (2020). ‘Candidatus Liberibacter Solanacearum’ Is Unlikely to Be Transmitted Spontaneously from Infected Carrot Plants to Citrus Plants by Trioza Erytreae. Insects, 11(8), 514. doi:10.3390/insects1108051
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