107,760 research outputs found
Discomfort from sinusoidal oscillation in the roll and lateral axes at frequencies between 0.2 and 1.6 Hz
No full textFull Bibliography References of Andrew H Wyllie from ANDREW DAVID HAMILTON WYLLIE. 24 January 1944 — 26 May 2022
No full textAndrew Wyllie graduated from the University of Aberdeen, becoming an academic pathologist in Aberdeen, Edinburgh and Cambridge. He was the co-discoverer of apoptotic cell death, having observed single cells dying following carcinogen exposure. Together with Alastair Currie and John Kerr, he realized the profound importance of this novel mode of cell death that showed a distinctive series of morphological changes, which he first described as a new cell death process. Wyllie and Currie introduced the term ‘apoptosis’ for this cell death process in a seminal paper in 1972. Another landmark discovery was of chromatin fragmentation in apoptosis, due to activation of an endogenous endonuclease that caused internucleosomal DNA cleavage (‘chromatin laddering’), which was the first biochemical mechanism of apoptosis described. He further characterized chromatin fragmentation in the 1980s, followed by investigations of cell surface changes to produce ‘eat-me’ signals to trigger rapid phagocytosis of the apoptotic cells and bodies, intracellular calcium ion signalling, caspase activation and other mechanisms of apoptosis. His cancer research helped identify the location of APC and generated his demonstration that apoptosis was regulated by oncogenes MYC and RAS and by tumour suppressor genes, such as TP53. He showed how apoptosis occurred in response to DNA damage and was a key process influencing both carcinogenesis and tumour growth. Andrew made a major scientific observation that changed the understanding of how cells die in health and disease, although it took time for the scientific establishment to understand its fundamental importance. Andrew Wyllie is widely known as the ‘Father of Apoptosis’
Discomfort from sinusoidal oscillation in the pitch and fore-and-aft axes at frequencies between 0.2 and 1.6 Hz
No full textLow frequency pitch and fore-and-aft oscillations arise in many modes of transport. Pitch oscillation rotates a seat through the gravity vector giving rise to a fore-and-aft acceleration in the plane of the seat: the measurement of fore-and-aft acceleration does not discriminate between the component of this acceleration arising from pitch and the component arising from horizontal acceleration in the fore-and-aft direction. The objectives of this study were to investigate whether fore-and-aft acceleration in the plane of the seat was an adequate predictor of vibration discomfort arising from low frequency oscillation in both the pitch and fore-and-aft axes, and to determine the effect of a backrest on discomfort during pitch and fore-and-aft oscillation at low frequencies. Twelve male subjects used the method of magnitude estimation to judge the discomfort produced by sinusoidal oscillations in the pitch and fore-and-aft axes at 10 frequencies between 0.2 and 1.6 Hz, while seated with and without a backrest. For both pitch and fore-and-aft oscillation, the rate of growth of discomfort with increasing vibration magnitude decreased with increasing frequency of oscillation, indicating that the frequency-dependence of discomfort is magnitude-dependent. At frequencies greater than about 0.4 Hz with a backrest, and at frequencies greater than about 0.8 Hz without a backrest, fore-and-aft acceleration in the plane of the seat arising from pitch oscillation caused greater discomfort than the same acceleration produced by fore-and-aft oscillation. A backrest increased discomfort with pitch oscillation at frequencies greater than about 0.63 Hz, but tended to decrease discomfort during fore-and-aft oscillation. The prediction of discomfort caused by low frequency pitch and fore-and-aft oscillation requires that both components are measured and assessed according to their separate effects, taking into account any beneficial and detrimental effects of a backres
Discomfort from sinusoidal oscillation in the roll and lateral axes at frequencies between 0.2 and 1.6 Hz
No full textDiscomfort caused by low frequency lateral and roll oscillations is often predicted from lateral acceleration in the plane of the seat, irrespective of whether it comes from horizontal motion or a component of gravity arising from roll. This study investigated discomfort from lateral and roll oscillation and whether acceleration in the plane of a seat predicts discomfort. Twelve subjects, sitting with and without backrest, used magnitude estimation to judge sinusoidal oscillations in the roll and lateral axes at ten frequencies between 0.2 and 1.6 Hz at magnitudes between 0.063 and 0.63 m s?2 root mean square. The rate of growth of vibration discomfort with increasing magnitude reduced with increasing frequency, so the frequency-dependence of discomfort varied with magnitude. Acceleration in the plane of the seat predicted discomfort from both lateral and roll oscillation at frequencies less than 0.4 Hz. At higher frequencies, acceleration produced by roll oscillation resulted in greater discomfort than the same acceleration produced by lateral oscillation. At frequencies greater than 0.4 Hz, a full height backrest increased discomfort with both lateral and roll oscillation. The prediction of discomfort caused by low frequency lateral and roll oscillation requires that both components are measured and assessed according to their separate effects
Going Beyond Counting First Authors in Author Co-citation Analysis
No full textThe 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
Magmatic consequences of volatile fluxes from the mantle
No full textThe 1959 translation of Korzhinskii's book Physicochemical Basis of the Analysis of the
Paragenesis of Minerals introduced me to the concept of inert and perfectly mobile
components in open systems. At that time, O.F. Tuttle and I were studying phase
relationships in the systems CaO-CO_2-H_2O and MgO-CO_2-H_2O (Wyllie & Tuttle,
1960, Walter et al., 1962, Wyllie, 1962), with the volatile components contained
securely inside closed gold capsules and therefore thermodynamically inert. The results
were to be applied to carbonatites, igneous rocks through which there is no doubt that
volatile components have flowed influentially. In Korzhinskii's book I discovered how
to represent the volatile components CO_2 and H_2O in chemical potential diagrams,
applicable to both closed and open systems. The method was also applied to many
other systems, including granitic rocks with mineralogy controlled by the chemical
potentials of sodium and potassium. Korzhinskii's work has provided the basis for
quantitative treatment of metasomatism.
Metasomatic processes, originally studied in connection with crustal rocks, are now
believed to be important in the mantle, as well. There is evidence that peridotite nodules
brought to the surface in kimberlites or alkali basalts were metasomatized within the
mantle before being transported by their igneous hosts (e.g. Boettcher & O'Neill, 1980,
Dawson, 1980, pp. 183- 5; Harte, 1983), and mantle metasomatism is commonly
assumed to explain the observation that many basaltic magmas have trace element and
isotope geochemistry that is difficult to explain in terms of partial melting of upper
mantle rocks with compositions considered to be normal (Walker, 1983). Extension of
phase equilibrium studies involving volatile components to mantle pressures (e.g.
CaO- MgO-SiO_2-CO_2-H_2O; Wyllie & Huang, 1976, Eggler, 1978, Ell is & Wyllie,
1980) have provided applications to the petrogenesis of kimberlites, probably the most
volatile-charged magmas rising from the mantle.
When Dawson (1980) reviewed hypotheses for the origin of kimberlites he concluded
that experimental evidence supported their generation by the partial melting of
phlogopite-carbonate-garnet lherzolite. By this time I had concluded (Wyllie, 1980)
that the existence of such-rocks in the kimberlite source regions was unlikely, unless
temperatures were extraordinarily low, and I was impressed by the evidence that the
mantle oxygen fugacity may be too low for the formation or survival of such rocks in
the base of the lithosphere. This led me to formulate a model involving the migration
from the deep mantle of reduced vapors with major components C-H-O, which
generated kimberlite melts in the asthenosphere, with the melts subsequently being
erupted from the deep lithosphere. This contribution outlines the possible effects of
intermittent fluxes of reduced volatile components from the mantle, into and through
the lithosphere. Similar themes have been developed by Perchuk (1976), Bailey (1985)
and Green et al. (1987), although Bailey (1985) assigned a major role to oxidized CO_2
Appropriate Similarity Measures for Author Cocitation Analysis
No full textWe 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
No full textWe 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
The construction of Karen Karnak: The multi-author-function
No full textThis thesis is situated within the comparatively recent developments of Web 2.0 and the emergence of interactive WikiMedia, and explores the mode of authorship within a Read/Write culture compared to that of a Read/Only tradition. The hypothesis of this study is that the role of the audience has become merged with the author, and as such, represents new functions and attributes, distinct from a more conventional concept of authorship, in which the roles of audience and author are more separate. Read/Write and participatory culture, as defined by this study, is focused on collaboration, and includes the influences of D.I.Y. culture, Open-Source practices and the production of text by multiple authors. Multi-authorship presents a re-thinking of several concepts which support the notion of the individual author, since the focus of multi-authorship is not on attribution and ownership of a finished text, but on the continued malleability of a text. Modes of multi-authorship, demonstrated in the use of the pseudonyms Alan Smithee and Karen Eliot, represent declarative authors whose names signify multiple origins, whilst concurrently indicating a distinct body of work. The function of these names form an important context to this study, since primary research involves the construction of an experimental mode of multi-authorship utilising WikiMedia technology and the interaction of thirty nine participants, who are invited to create a body of work under the collective pseudonym Karen Karnak. The data generated by this experiment is analysed using aspects of Michel Foucault's author-function to identify and determine power structures inherent in the WikiMedia context. The interplay of power structures, including concepts such as identity, ownership and the body of work, affect the resulting mode of authorship and contribute to the construction of Karen Karnak, suggesting further areas of research into the emerging multi-author
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