1,721,175 research outputs found
Antarctic climate: ocean fluxes and variability
No full textThe Southern Ocean plays a major role in the global overturning circulation, providingan important route for the return flow of deep water subducted in the North Atlantic.The World Ocean Circulation Experiment (WOCE) provided an unprecedented pictureof the state of the world’s oceans and set new standards for high quality in-situhydrographic data. This study combines the existing WOCE data set with newhydrographic sections, and output from global and regional ocean models to examinethe mean state of the Southern Ocean circulation and the balance of fluxes around theAntarctic Circumpolar current.A historical data set in the region of Drake Passage is examined to study the large-scalewater mass variability between 1926-2005. The water mass properties of the LowerCircumpolar Deep Water is constant within error bounds throughout the data set. Awarming and freshening signal in the surface waters from 1997-2005 to the north of theSub-Antarctic Front along SR01b is also presented.The major part of this work is based around an inverse study of the Southern Ocean thatcombines the WOCE data-set with contemporary sections, and other forcing fields toexamine the balance of fluxes throughout the Southern Ocean. The study examines theeffect of different parameterisations of the dianeutral mixing in the Southern Ocean, inlight of the differing views of localised deep turbulent mixing from observations, and anadiabatic ocean interior from residual mean studies, The freshwater balance in themodel is presented and its implications on the water mass formation and transformationof the upper and lower cells of the overturning circulation is discussed in detail
Beyond a series of security nets: applying STAMP & STPA to port security
No full textPort security is an increasing concern given the significant role of ports in global commerce and today’s increasingly complex threat environment. Current approaches to port security mirror traditional models of accident causality – ‘a series of security nets’ based on component reliability and probabilistic assumptions. Traditional port security frameworks result in isolated and inconsistent improvement strategies. Recent work in engineered safety combines the ideas of hierarchy, emergence, control and communication into a new paradigm for understanding port security as an emergent complex system property. The ‘System-Theoretic Accident Model and Process (STAMP)’ is a new model of causality based on systems and control theory. The associated analysis process – System Theoretic Process Analysis (STPA) – identifies specific technical or procedural security requirements designed to work in coordination with (and be traceable to) overall port objectives. This process yields port security design specifications that can mitigate (if not eliminate) port security vulnerabilities related to an emphasis on component reliability, lack of coordination between port security stakeholders or economic pressures endemic in the maritime industry. This article aims to demonstrate how STAMP’s broader view of causality and complexity can better address the dynamic and interactive behaviors of social, organizational and technical components of port security.Sandia National Laboratories (Doctoral Studies Program
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
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
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
The three-dimensional overturning circulation of the Southern Ocean during the WOCE era
No full textA box inverse model of the Southern Ocean during the World Ocean Circulation Experiment is constructed to investigate the three-dimensional structure of the regional overturning circulation in that era. The model has many features in common with various preceding inverse studies, but also contains several novel elements that make it well suited for addressing many of the significant uncertainties that surround the circulation at present. The net overturning circulation of the Southern Ocean is found to consist of two well-defined cells of similar strength. The upper cell consists of a northward transport of 18.8 ± 5.5 Sv of surface, mode and intermediate waters lighter than the 27.5 kg m−3 isoneutral, and an equivalent southward flow in the approximate 27.5–27.9 kg m−3 neutral density range, encompassing the bulk of the Upper Circumpolar Deep Water. The lower cell involves the northward export of 18.6 ± 0.9 Sv of Antarctic Bottom Water and Lower Circumpolar Deep Water denser than 28.08 kg m−3, and an opposing transport in the lighter classes of that water mass. Substantial structural differences between the overturning circulations of the Atlantic, Indian and Pacific basins are indicated by the model’s solution. Overall, the diagnosed Southern Ocean circulation shares many qualitative and some quantitative features with previous inverse estimates, particularly as regards the large-scale, depth-integrated lateral circulation and associated energy fluxes in the subtropics and in the Antarctic Circumpolar Current, and the strength of the upper overturning cell. However, it also suggests several significant adjustments to current views of the regional circulation. Most notable amongst these are: the subpolar circulation of the Southern Ocean is more vigorous and zonally interconnected than generally thought; the associated lower overturning cell is more intense than indicated by most preceding estimates; contrary to common perception, sub-surface mixing processes play a role of comparable importance to air–sea–ice exchanges of buoyancy in underpinning the dianeutral closure of the Southern Ocean overturning, even at shallow (mode and intermediate water) levels; and the connection between North Atlantic deep water formation and Southern Ocean upwelling is fundamentally three-dimensional, such that deep waters from the North Atlantic must upwell dianeutrally before being returned to the permanent pycnocline of the northern oceans
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