1,721,025 research outputs found
Distribution of Devensian glacial erratics and related evidence elucidate complex ice flow changes across a former ice divide: Northern England
No full textThe Lune Gorge and the uplands of the southern Shap Fells represent a key area in developing an understanding of the dynamics of the Late Devensian glaciation (Dimlington Stadial) of northern England. Here ice masses emanating from southern Scotland, the Lake District and the Howgill Fells interacted in the area of the upper Lune valley. Glacial landforms are recorded and tills noted. The dispersal pattern of Shap granite (Sg) erratics is mapped as these clasts are an important tracer of regional ice movements and local ice dynamics. This new information is synthesised with existing literature to provide an understanding of ice dynamics in an area of complex ice flow history. In particular, the ice flow interactions over an area of the western Pennines and the southern Shap Fells have been defined. Early Dimlington ice flow in the vicinity of the upper Lune valley was easterly. Later a northerly shift in the position of a regionally significant west–east aligned ice divide led to topographic steering of southerly basal ice flows, resulting in the development of a western ice stream (Mint Sg plume) and an eastern ice stream (Lune Sg plume); both flowing south around the massif of the southern Shap Fells. At that time, southerly flow of basal ice over the highest ridges of the Grayrigg massif in the southern Shap Fells was relatively weak. Whereas the western stream extended into the Lancashire lowlands, the eastern ice stream was impeded in the Lune Gorge by ice emanating from Borrowdale which forced northern ice to the eastern side of the Lune Gorge where it was blocked by western flowing Howgill ice; the latter extending as far as just east of Kendal. During the late Dimlington, the ice masses over the Mint valley and the southern Shap Fells largely thinned and retreated to the north and west, with a surge in northerly ice movement within the upper Lune valley that did not override the western Pennines. Local ice dynamics are well-illustrated in the western margin of the Pennines (Crosby Ravensworth Fell [sbnd] Gaythorne Plain), where the disposition of erratics reflects local late west-to-east weak down-wasting ice flow and the presence of subglacial meltwater drainage channels. However, ice ultimately decayed in situ on Crosby Ravensworth Fell [sbnd] Gaythorne Plain. Similarly, after complex variable easterly and southerly ice flow during the early Dimlington, there was weak northerly ice flow in the later phase over Birkbeck Fells Common before ice thinned and retreated from Grayrigg Forest. An extensive ice stream, fed by ice emanating from an ice dispersal centre in the eastern Lake District, occupied the large trough of Borrowdale that transverses the southern Shap Fells, but its extension and recession dynamics remain enigmatic. “Glacial Theory …, in its application to the transport of blocks across Stainmoor, involves such obvious mechanical absurdities that the author considers it totally unworthy of the attention of the Society.”</p
Fitting limit lines (envelope curves) to spreads of geoenvironmental data
No full textGeoscientists frequently are interested in defining the overall trend in x-y data clouds using techniques such as least squares regression. Yet often the sample data exhibits considerable spread of y-values for given x-values, which is itself of interest. In some cases the data may exhibit a distinct visual upper (or lower) ‘limit’ to a broad spread of y-values for a given x-value, defined by a marked reduction in concentration of y-values. As a function of x-value, the locus of this “limit” defines a “limit line”, with no (or few) points lying above (or below) it. Despite numerous examples of such situations in geoscience, there has been little consideration within the general geoenvironmental literature of methods used to define limit lines (sometimes termed ‘envelope curves’ when they enclose all data of interest). In this work, methods to fit limit lines are reviewed. Many commonly applied methods are ad-hoc and statistically not well founded, often because the data sample available is small and noisy. Other methods are considered which correspond to specific statistical models offering more objective and reproducible estimation. The strengths and weaknesses of methods are considered by application to real geoscience data sets. Wider adoption of statistical models would enhance confidence in the utility of fitted limits and promote statistical developments in limit fitting methodologies which are likely to be transformative in the interpretation of limits. Supplements, a spreadsheet and references to software are provided for ready application by geoscientists
Engaging employees for success: Enhancing generational performance and closing generational divide / Lee Su Teng
No full textThe primary aim of this research is to examine the generational differences in
the engagement model. The study set out to examine the mediating influence of
employee engagement in the relations between motivators and consequences, and
whether this relationship is moderated by generations. This study consists of two
phases. Phase 1 was a one-to-one interview of 63 participants while phase 2 was a
survey study of 539 respondents. The unit of analysis is individuals who represent
Malaysian employees from different organisations in Peninsular Malaysia. This study
is backed by well-established theory from social psychology, the social exchange
theory. IBM Statistical Package for Social Sciences (SPSS) Statistics 20 was used to
perform exploratory factor analysis (EFA), reliability tests and preliminary correlation
analysis. In addition, IBM SPSS Analysis of Moment Structures (Amos) 18 was used
to test the hypotheses of the study. Findings show that there are generational
differences in the Malaysia context. There are significant local historical events, work
values, expectations, perceptions, behaviours, goal, leadership style and motivators
for each generation. Results also show that each generation reacts differently to the
motivators of employee engagement. To engage Boomers, employers should focus on
reward and recognition from the immediate supervisor and colleague, as well as
autonomy. For the engagement of Generation X, leaders can consider implementing
work-life balance programme, autonomy as well as reward and recognition from the
Management. In order to engage Generation Y, what they want is just reward and
recognition from the immediate supervisor and colleague, as well as work-life
balance. It was found that engaged employees from Generation X and Y have lower
intention to leave, increased in-role performance and innovative job performance.
However, engaged Boomers only displayed increased in-role performance. All these
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lead to finding new and more harmonious ways of establishing working relationships
and engaging the employees for all generations
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
Flow structure in large bedrock-channels: The example of macroturbulent rapids, lower Mekong River, Southeast Asia
No full textThe rate of bedrock channel incision is key to the understanding of landscape evolution. Theoretical models relate channel incision to sediment transport; the latter conditioned by the bed shear stress. However, theory is deficient in an appreciation of the transverse and vertical flow structure that mediates shear stress for deep, narrow inner-channels, which often characterize large bedrock rivers. Here we present the detail of the structure of high Reynolds number flows for bedrock-controlled rapids of the Mekong River, SE Asia. Distinct filaments of high-velocity flow, separated by regions of slower flow, occur across channels; the numbers of filaments scale linearly with channel width to maximum-depth (B/hmax) ratios. Inner-channels with low ratios (B/hmax < 20) exhibit wall-effected flow structure. Effects include suppressed maximum velocity filaments due to: (i) significant channel-transverse flow; (ii) strongly-sheared vertical flow structure; and (iii) significant underflows. Such complex water column flow patterns largely defy theoretical description. Nonetheless near the bed, the vertical velocity distributions often conform to: (i) ‘law-of-the-wall’ logarithmic theory; or (ii) profiles in the near-bed region and within the transition to outer flow can be described using a log-wake function. Consequently, for selected velocity profiles it is possible to derive hydraulic parameters suitable for input to incision models. Chezy-C values are high, indicating low flow resistance, while bed shear stresses remain competent, even during low-discharges, to transport cobble bedload across low roughness bedrock surfaces. Thus, as competence is high, no blanketing sediment deposits can develop within inner channels to prevent bedrock erosion. Consequently, within similar high competence systems, incision is probably progressive as long as sediment supply is sustained to abrade the bedrock. The landscape modelling implication is that abrasion in this system is supply-limited and not limited by flow competence. In contrast, a transport-limited system is likely to evolve to exhibit an alluvial bed.</p
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
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
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