1,720,974 research outputs found
Repair and remodelling in the shells of the limpet Patella vulgata
No full textLimpets and other molluscs rely on shells to protect them from physical damage, predation, dehydration, etc. If the shell becomes damaged, this may significantly impair its function. In this work, experiments were carried out to investigate the effect of damage on the strength of shells of the common limpet (Patella vulgata) and their ability to repair this damage effectively. Shells were damaged in three ways: (i) low-energy impacts; (ii) abrasion of the outer layer; and (iii) creation of a small hole in the apex of the shell. Shells were left to repair for several time periods (0, 10, 30 and 60 days). The mechanical strength was evaluated by impacting the shells with a weight dropped from a known height. The damage reduced the strength (defined as impact energy to failure) by 50–70% depending on damage type. After 60 days, limpets in all three groups had repaired their shells significantly, bringing their strength to 79–91% of the control value (in each case, samples were statistically indistinguishable from their control counterparts). Measurements of the thickness of the shell at the apex suggest that the main effect of low-energy impact and abrasion is reduction in thickness, which correlates linearly with the impact energy needed for failure. The method of repair is believed to be by the growth of fresh shell material on the inside of the shell, though we could not identify this new material specifically. Even after 60 days, the shells were still statistically thinner than the controls. Consequently, there may be some other strengthening mechanism at work. This work has demonstrated the remarkable ability of limpets to detect the mechanical weakening of their shells caused by relatively subtle forms of damage and to take appropriate action to restore shell strength. © 2018 The Author(s) Published by the Royal Society. All rights reserved
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe 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
Full text link“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
Full text linkWe 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
DLP-Printable Porous Cryogels for 3D Soft Tactile Sensing
Full text linkThree-Dimensional (3D) printed porous materials hold the potential for various soft sensing applications due to their remarkable flexibility, low density, and customizable geometries. However, developing versatile and efficient fabrication methods is crucial to unlock their full potential. A novel approach is introduced by combining Digital Light Processing (DLP) 3D printing and freeze-drying to manufacture deformable cryogels featuring intricate morphologies. Photocurable hydrogels based on Poly(3,4-ethylenedioxythiophene)Polystyrene sulfonate (PEDOT:PSS), Polyethylene glycol Diacrylate (PEGDA) and Ethylene Glycol (EG) are successfully printed and lyophilized. In this way, porous cryogels with tailorable properties are achieved. Microporosity varies from 68% to 96%, according to the chemical composition. Ultra-soft cryogels with a compressive modulus of 0.13MPa are fabricated by adding a reactive diluent. As a result of the cryogelation process, which effectively removes water from the hydrogels, microporous structures with details as fine as 100 mu m are obtained. The achieved freedom of design is exploited to fabricate resistive force sensors with a honeycomb lattice morphology. The sensitivity and the working range of the sensors can be tailored by tuning the size of the cells, paving the way for sensors with programmable architectures that can meet diverse requirements.A dual-step approach combining Digital Light Processing (DLP) 3D printing and lyophilization transforms printed hydrogels into porous cryogels with complex shapes. Porosity and mechanical properties are finely controlled based on the chemical composition of starting formulations. Microporous cryogels with details down to 100 mu m are printed. Proof-of-concept scalable soft force sensors show a tuneable response based on the geometry of the core 3D honeycomb architecture. imag
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe 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
3D printing of fully cellulose-based hydrogels by digital light processing
Full text linkWe report on the development of natural-based, composite hydrogel inks for Digital Light Processing (DLP) 3D printing, composed entirely of cellulose-based-materials. DLP, which enables the production of complex constructs by photopolymerization, is already considered an environmentally friendly production method but it is still based on fossil chemicals, which may be a limit in the future. On the contrary, in view of a more environmental-friendly production, the development of natural inks will represent a further step to its wide-scale adoption. Here acrylated-carboxymethyl cellulose (mCMC) hydrogels are reinforced by the addition of biowastes-sourced cellulose nanocrystals (NCs) derived from oil palm empty fruit bunch, both pristine and functionalized, to produce hybrid polymeric networks. It is demonstrated that the addition of such fillers does not affect the photocuring properties of the formulations while improving their printability through improvement in the mechanical properties, even with high content of water (97 wt%). Furthermore, the printable hydrogels present intriguing characteristics such as controlled swelling and pH sensitivity. The use of fully-natural derived material with designed properties and complex geometries can open further perspectives in many fields, such as sensors, biomedical and soft robotics
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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