1,720,980 research outputs found
Modelling and safety assessment of observed sliding damage in a masonry rib vault
Get PDFFrequently observed damage in historic masonry vaults has always given rise to concerns on their stabil-ity. The effect of present damage on masonry vaults structural response should be taken into considera-tion during structural analysis as it clearly affects its behavior.The aim is to propose a method to study the safety of vaults, setting up a finite element model with a limited number of discontinuities, based on the consideration of the vault construction and damage observation.A case study from Milan cathedral is adopted where damage is documented. A complex damage mechanism characterized by sliding of voussoirs and detachment of the rib from the web was docu-mented in the 1960s. The results show the possibility to analyze the evolution of the observed mecha-nism and to evaluate numerically its safety in function of the documented settlements.Technical applications of the present work include interpretations of the causes of observed damage, estimation of the level of settlements based on observed damage, and numerical evaluation of the safety of the current mechanical state
The Compact Body Plan of Tardigrades Evolved by the Loss of a Large Body Region
Get PDFThe superphylum Panarthropoda (Arthropoda, Onychophora,
and Tardigrada) exhibits a remarkable
diversity of segment morphologies, enabling these
animals to occupy diverse ecological niches. The
molecular identities of these segments are specified
by Hox genes and other axis patterning genes
during development [1, 2]. Comparisons of molecular
segment identities between arthropodandonychophoran
species have yielded important insights into the
origins and diversification of their body plans [3–9].
However, the relationship of the segments of tardigrades
to those of arthropods and onychophorans
has remained enigmatic [10, 11], limiting our understanding
of early panarthropod body plan diversification.
Here, we reveal molecular identities for all of the
segments of a tardigrade. Based on our analysis, we
conclude that tardigrades have lost a large intermediate
region of thebody axis—aregion correspondingto
the entire thorax and most of the abdomen of insects—
and that they have lost the Hox genes that
originally specified this region. Our data suggest that
nearly the entire tardigrade body axis is homologous
to just the head region of arthropods. Based on our results,
we reconstruct a last common ancestor of Panarthropoda
that had a relatively elongate body plan
like most arthropods and onychophorans, rather
than a compact, tardigrade-like body plan. These results
demonstrate that the body plan of an animal
phylum can originate by the loss of a large part of
the body
Production of reactive oxygen species and involvement of bioprotectants during anhydrobiosis in the tardigrade Paramacrobiotus spatialis
Get PDFWater unavailability is an abiotic stress causing unfavourable conditions for life. Nevertheless, some
animals evolved anhydrobiosis, a strategy allowing for the reversible organism dehydration and
suspension of metabolism as a direct response to habitat desiccation. Anhydrobiotic animals undergo
biochemical changes synthesizing bioprotectants to help combat desiccation stresses. One stress
is the generation of reactive oxygen species (ROS). In this study, the eutardigrade Paramacrobiotus
spatialis was used to investigate the occurrence of ROS associated with the desiccation process.
We observed that the production of ROS signifcantly increases as a function of time spent in
anhydrobiosis and represents a direct demonstration of oxidative stress in tardigrades. The degree
of involvement of bioprotectants, including those combating ROS, in the P. spatialis was evaluated
by perturbing their gene functions using RNA interference and assessing the successful recovery
of animals after desiccation/rehydration. Targeting the glutathione peroxidase gene compromised
survival during drying and rehydration, providing evidence for the role of the gene in desiccation
tolerance. Targeting genes encoding glutathione reductase and catalase indicated that these
molecules play roles during rehydration. Our study also confrms the involvement of aquaporins 3 and
10 during rehydration. Therefore, desiccation tolerance depends on the synergistic action of many
diferent molecules working together
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
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