298 research outputs found

    Nonlinear behavior of reinforced concrete structures under seismic excitation

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    Thesis (M. Eng.)--Massachusetts Institute of Technology, Dept. of Civil and Environmental Engineering, 2013.Cataloged from PDF version of thesis.Includes bibliographical references (p. 41).Exploring nonlinear behavior of structures through structural analysis software can be time and computer processing intensive especially with complicated structural models. This paper will explore the nonlinear behavior of a reinforced concrete structure with varying damping conditions that will experience a number of earthquakes at varying intensities. In the effort to produce a more accurate representation of the structural behavior, the building will be designed based on modem design codes. Ultimately, this approach aims to define a range in which engineers can use a linear approximation to determine certain performance metrics like interstory drift and floor accelerations.by Matthew Anthony Pires.M.Eng

    Constitution et exploitation d’un corpus de français parlĂ© parisien

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    Le but de cet article est double. Il s’agit d’abord d’introduire un nouveau corpus de français oral numĂ©risĂ©, accessible sans restriction sur le web. CFPP2000 (Corpus du français parlĂ© parisien des annĂ©es 2000), qui comporte actuellement 500 000 mots alignĂ©s Ă  l’oral au tour de parole, est constituĂ© par un ensemble d’interviews conversationnelles sur les quartiers de Paris d’une Ă  deux heures qui ont Ă©tĂ© rĂ©alisĂ©es en dyades ou le plus souvent en triades. L’article envisage l’influence pour la constitution du corpus du but que nous nous Ă©tions fixĂ© au dĂ©part, faciliter l’étude de la variation Ă  l’oral pour le français parisien « commun ». Il aborde le choix des informateurs qui dĂ©coule de cet objectif, les conduites d’entretien qui ont Ă©tĂ© adoptĂ©es. Il envisage ce qu’apporte la transcription d’entretiens relativement longs qui permet d’attĂ©nuer l’opposition entre analyse quantitative et analyse qualitative, ainsi que les prĂ©cautions Ă  prendre dans l’interprĂ©tation des rĂ©sultats. Dans un deuxiĂšme temps, l’article prĂ©sente les mĂ©tadonnĂ©es, les concordanciers et les outils statistiques qui viennent enrichir le corpus et mentionne quelques travaux qu’il a permis de mener, tantĂŽt en syntaxe de l’oral, tantĂŽt autour de problĂšmes de variation morphologique.Creating and exploiting a corpus of Parisian spoken French This article has two aims. Firstly, it introduces a new digitized corpus of spoken French, freely accessible on the internet. The CFPP2000 (Corpus du Français ParlĂ© Parisien des annĂ©es 2000) presently features 500,000 words aligned to speech turns, and taken from a collection of conversational interviews themed around the local areas of Paris. These last from one to two hours and were conducted with one, two or sometimes more respondents. The article looks at how the original aim of contributing to the study of spoken variation for “ordinary” Paris French has influenced the make-up of the corpus. It considers how this weighed on the choice of respondents, and on the way the interviews were conducted. It looks at the advantage of transcribing relatively long interviews, where the opposition between quantitative and qualitative analysis may be attenuated, and mentions precautions which are necessary when interpreting results. Secondly, the article presents the metadata, concordancers and statistical tools which have been added to enhance use of the corpus, and mentions some studies in which it has been used, from the area of spoken syntax and morphological variation

    De-personifying Collaert's Four Continents: European descriptions of continental diversity, 1585–1625

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    Adriaen Collaert's personifications of the four continents are typical examples of how continents and their respective cultures were represented in the art and literature of Europe in the early-modern period. For example, Asia is the exotic double to Europe, possessing an ‘otherness’ upon which European identity has been juxtaposed. Such personifications of continents and broader tropes of ‘the other’ and ‘the exotic’ have greatly influenced the historiography of the idea of Europe. However, the creation of art and literature characterised by these tropes reflects only part of the European understanding of the wider world. This article will explore how travellers – such as missionaries, merchants and ambassadors – in Europe's encounters with non-European societies presented a complex picture of the world sought to offer practical guidance and knowledge. How travellers’ accounts and personifications interacted is important for understanding the European experience of other continents. In considering how travellers presented their knowledge of continents, it is possible to analyse both how early-modern Europeans viewed other continents and question how useful artistic representation of ‘other’ continents are for understanding how they viewed their own

    Syntheses, characterization, density functional theory calculations, and activity of tridentate SNS zinc pincer complexes

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    A series of tridentate SNS ligand precursors were metallated with ZnCl2 to give new tridentate SNS pincer zinc complexes. The zinc complexes serve as models for the zinc active site in liver alcohol dehydrogenase (LADH) and were characterized with single crystal X-ray diffraction, 1H, 13C, and HSQC NMR spectroscopies and electrospray mass spectrometry. The bond lengths and bond angles of the zinc complexes correlate well to those in horse LADH. The zinc complexes feature SNS donor atoms and pseudotetrahedral geometry about the zinc center, as is seen for liver alcohol dehydrogenase. The SNS ligand precursors were characterized with 1H, 13C, and HSQC NMR spectroscopies and cyclic voltammetry, and were found to be redox active. Gaussian calculations were performed and agree quite well with the experimentally observed oxidation potential for the pincer ligand. The zinc complexes were screened for the reduction of electron poor aldehydes in the presence of a hydrogen donor, 1-benzyl-1,4-dihydronicotinamide (BNAH). The zinc complexes enhance the reduction of electron poor aldehydes. Density functional theory calculations were performed to better understand why the geometry about the zinc center is pseudo-tetrahedral rather than pseudo-square planar, which is seen for most pincer complexes. For the SNS tridentate pincer complexes, the data indicate that the pseudo-tetrahedral geometry was 43.8 kcal/mol more stable than the pseudo-square planar geometry. Density functional theory calculations were also performed on zinc complexes with monodentate ligands and the data indicate that the pseudo-tetrahedral geometry was 30.6 kcal/mol more stable than pseudo-square planar geometry. Overall, the relative stabilities of the pseudo-tetrahedral and pseudo-square planar systems are the same for this coordination environment whether the ligand set is a single tridentate SNS system or is broken into three separate units. The preference of a d10 Zn center to attain a tetrahedral local environment trumps any stabilization gained by removal of constraints within the ligand set

    BioSentinel: Monitoring DNA Damage Repair Beyond Low Earth Orbit on a 6U Nanosatellite

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    We are designing and developing a 6U nanosatellite as a secondary payload to fly aboard NASAs Space Launch System (SLS) Exploration Mission (EM) 1, scheduled for launch in late 2017. For the first time in over forty years, direct experimental data from biological studies beyond low Earth orbit (LEO) will be obtained during BioSentinels 12- to 18-month mission. BioSentinel will measure the damage and repair of DNA in a biological organism and allow us to compare that to information from onboard physical radiation sensors. This data will be available for validation of existing models and for extrapolation to humans.The BioSentinel experiment will use the organism Saccharomyces cerevisiae (yeast) to report DNA double-strand-break (DSB) events that result from space radiation. DSB repair exhibits striking conservation of repair proteins from yeast to humans. The flight strain will include engineered genetic defects that prevent growth and division until a radiation-induced DSB activates the yeasts DNA repair mechanisms. The triggered culture growth and metabolic activity directly indicate a DSB and its repair. The yeast will be carried in the dry state in independent microwells with support electronics. The measurement subsystem will sequentially activate and monitor wells, optically tracking cell growth and metabolism. BioSentinel will also include TimePix radiation sensors implemented by JSCs RadWorks group. Dose and Linear Energy Transfer (LET) data will be compared directly to the rate of DSB-and-repair events measured by the S. cerevisiae biosentinels. BioSentinel will mature nanosatellite technologies to include: deep space communications and navigation, autonomous attitude control and momentum management, and micropropulsion systems to provide an adaptable nanosatellite platform for deep space uses

    De novo human angiotensin-converting enzyme 2 decoy NL-CVX1 protects mice from severe disease after severe acute respiratory syndrome Coronavirus 2 infection

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    © The Author(s) 2023. Published by Oxford University Press on behalf of Infectious Diseases Society of America. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0/), which permits unrestricted reuse, distribution, and reproduction in any medium, provided the original work is properly cited.The emergence of novel variants of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) underscores the need to investigate alternative approaches to prevent infection and treat patients with coronavirus disease 2019. Here, we report the preclinical efficacy of NL-CVX1, a de novo decoy that blocks virus entry into cells by binding with nanomolar affinity and high specificity to the receptor-binding domain of the SARS-CoV-2 spike protein. Using a transgenic mouse model of SARS-CoV-2 infection, we showed that a single prophylactic intranasal dose of NL-CVX1 conferred complete protection from severe disease following SARS-CoV-2 infection. Multiple therapeutic administrations of NL-CVX1 also protected mice from succumbing to infection. Finally, we showed that infected mice treated with NL-CVX1 developed both anti-SARS-CoV-2 antibodies and memory T cells and were protected against reinfection a month after treatment. Overall, these observations suggest NL-CVX1 is a promising therapeutic candidate for preventing and treating severe SARS-CoV-2 infections.This project has received funding from the European Union's Horizon 2020 research and innovation programme under grant agreements number 852985.info:eu-repo/semantics/publishedVersio

    De novo human angiotensin - converting enzyme 2 Decoy NL-CVX1 protects mice from severe disease after severe acute respiratory syndrome coronavirus 2 infection

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    The emergence of novel variants of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) underscores the need to investigate alternative approaches to prevent infection and treat patients with coronavirus disease 2019. Here, we report the preclinical efficacy of NL-CVX1, a de novo decoy that blocks virus entry into cells by binding with nanomolar affinity and high specificity to the receptor-binding domain of the SARS-CoV-2 spike protein. Using a transgenic mouse model of SARS-CoV-2 infection, we showed that a single prophylactic intranasal dose of NL-CVX1 conferred complete protection from severe disease following SARS-CoV-2 infection. Multiple therapeutic administrations of NL-CVX1 also protected mice from succumbing to infection. Finally, we showed that infected mice treated with NL-CVX1 developed both anti-SARS-CoV-2 antibodies and memory T cells and were protected against reinfection a month after treatment. Overall, these observations suggest NL-CVX1 is a promising therapeutic candidate for preventing and treating severe SARS-CoV-2 infections.info:eu-repo/semantics/publishedVersio

    Guided portfolio writing as a scaffold for reïŹ‚ective learning in in-service contexts: A case study

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    Language is widely recognized as an inescapable mediating tool for professional learning, and with this text we want to contribute to a better understanding of the particular role that guided writing can play in in-service professional reïŹ‚ective learning. We analysed one pre-school teacher’s written portfolio, the construction of which was guided to scaffold deep thinking about (and the transference of theory into) practice during participation in an in-service program about language education. Our case study shows that the writing process sustained robust learning about professional knowing, doing and learning itself: The teacher elaborated an integrative ethical understanding of the discussed theory, fully experienced newly informed practices and assessed her own learning by using theory to confront her previous knowledge and practices. Throughout the portfolio, the learning stance revealed by her voice varied accordingly. The study illustrates the potential of guided writing to scaffold reïŹ‚ective learning in in-service contexts.Fundação para a CiĂȘncia e a Tecnologia (FCT), Portugal. PEst-OE/CED/UI1661/2011] through CIEd (Centro de Estudos em Educação). PEst-OE/CED/UI0317/2014] through CIEC.info:eu-repo/semantics/publishedVersio

    Vacuum Instabilities with a Wrong-Sign Higgs-Gluon-Gluon Amplitude

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    The recently discovered 125 GeV boson appears very similar to a Standard Model Higgs, but with data favoring an enhanced h to gamma gamma rate. A number of groups have found that fits would allow (or, less so after the latest updates, prefer) that the h-t-tbar coupling have the opposite sign. This can be given meaning in the context of an electroweak chiral Lagrangian, but it might also be interpreted to mean that a new colored and charged particle runs in loops and produces the opposite-sign hGG amplitude to that generated by integrating out the top, as well as a contribution reinforcing the W-loop contribution to hFF. In order to not suppress the rate of h to WW and h to ZZ, which appear to be approximately Standard Model-like, one would need the loop to "overshoot," not only canceling the top contribution but producing an opposite-sign hGG vertex of about the same magnitude as that in the SM. We argue that most such explanations have severe problems with fine-tuning and, more importantly, vacuum stability. In particular, the case of stop loops producing an opposite-sign hGG vertex of the same size as the Standard Model one is ruled out by a combination of vacuum decay bounds and LEP constraints. We also show that scenarios with a sign flip from loops of color octet charged scalars or new fermionic states are highly constrained.Comment: 20 pages, 8 figures; v2: references adde

    Extended-spectrum ÎČ-lactamase-producing Escherichia coli in human-derived and foodchain-derived samples from England, Wales, and Scotland: an epidemiological surveillance and typing study

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    Background: Escherichia coli isolates producing extended-spectrum ÎČlactamases (‘ESBL-E. coli’) cause >5000 bacteraemias annually in the UK. The contribution of the food chain to this challenge is debated. Methods: Selective media were used to seek ESBL-E. coli in routinely-submitted human faeces, sewage, farm slurry, and retail foodstuffs in London, East Anglia, Northwest England, Scotland and Wales. Recovered isolates were sequenced and compared with 293 bloodstream and 83 veterinary surveillance ESBL-E. coli isolates from the same regions. Findings: 10.7% (2157/20243) of human faeces contained ESBL-E. coli, rising to 17.0% (678/3995) in London. ESBL-E. coli also were frequent in sewage and present in 65.4% (104/159) of retail chicken, but rare in other meats and absent from plant-based foods. Sequence Type (ST) 131 dominated among ESBL-E. coli from human blood (188/293, 64.2%), faeces (128/360, 35.6%) and sewage (14/65, 21.5%) with STs 38 and 648 also widespread; CTX-M-15 was the predominant ESBL in these lineages. By contrast, STs 602, 23, 117 - mostly with CTX-M-1 ESBL - dominated among food and veterinary isolates, with only two ST131 organisms recovered. ST10 occurred in both animals and humans: being frequent in surveillance bovines and representing 4.2% (15/360) of human faecal isolates (but only 1% [3/293] from bacteraemias); however both human and animal ST10 isolates were diverse in serotype. Interpretation: Most human bacteraemias with ESBL-E. coli in the UK involve successful human-associated STs, particularly ST131; non-human reservoirs made little contribution to invasive human disease. Funding: NIHR Policy Research
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