1,720,954 research outputs found
The inorganic carbonate chemistry of the southern Strait of Georgia
No full textA one-dimensional, biophysical, mixing layer model was modified to hindcast pH and aragonite saturation state (OmegaA) in the southern Strait of Georgia. The model skill in predicting spring phytoplankton bloom timing in previous studies was a key factor in its selection. Dissolved inorganic carbon (DIC) and total alkalinity (TA) were added as state variables, coupled to the existing nitrogen-based biological equations. Additional processes determined to be important to the system such as air-sea gas exchange and nutrient-limited excess carbon uptake were also implemented. pH and OmegaA could then be calculated from DIC and TA. Modeled DIC, TA, pH, and OmegaA were evaluated against data collected between 2003 and 2012. Modeled and observed quantities agreed except in some summers, with surface disagreement driven primarily by plume variability and subsurface disagreement driven primarily by model overproductivity. Model outputs demonstrated a near-surface seasonal cycle characterized by low pH and OmegaA in winter and high pH and OmegaA in summer. In order to evaluate the sensitivity of model pH and OmegaA to local forcing quantities, the model was run in one year increments over the period from 2001 through 2012. For each year, each of three forcing records (wind speed, freshwater flux, cloud fraction) was shifted across all possible years during the same period for a total of 432 experimental runs. When regressed against spring wind speed, model surface pH demonstrated a clear, negative correlation. Model spring OmegaA demonstrated a negative correlation to cloud fraction. Summer pH and OmegaA were most sensitive to freshwater flux, both showing negative correlations. Model pH and OmegaA sensitivity to freshwater TA and pH were also evaluated over the same period using a set of realisitic freshwater chemistry scenarios determined from observations in the Fraser River. Model pH and OmegaA demonstrated opposite correlations to freshwater TA with sensitivities at opposite extremes of freshwater pH. The sensitivity results identify important links between local processes and the carbonate chemistry in the southern Strait of Georgia, and perhaps provide some simple forecasting tools to be tested in the future.Science, Faculty ofEarth, Ocean and Atmospheric Sciences, Department ofGraduat
Wind-driven upwelling and nutrient supply in a productive estuarine sea
No full textMarine ecosystems are under increasing pressure due to climate change. Wind-driven circulation in the upper ocean is one of the primary ways that climate determines ecosystem behavior. One example is wind-driven upwelling of nutrients to the euphotic zone. In small enclosed seas where stratification is often strong and wind sporadic, the significance of nutrient upwelling is not well-established. These small systems can be important habitats for juvenile migrating fish such as Pacific salmon. In this thesis, wind-driven upwelling and the effect on surface nitrate availability were investigated in the Strait of Georgia on the Canadian Pacific coast using a high-resolution, coupled biophysical ocean model. This investigation was conducted in three parts. First, the model skill was evaluated against observations from local monitoring programs, and the sensitivity of tuning the surface wave breaking parameterization using wave model results from the region was tested. Second, principal component analysis (PCA) was performed on five years of modelled hourly surface nitrate and temperature fields to identify the wind-driven upwelling modes and determine their significance relative to other processes. Spectral analysis of the principal component (PC) loadings and correlations between the PC loadings and the surface wind stress were used to attribute the dominant PCA modes to physical phenomena. Third, depth of upwelling estimates from cross-shore density transects during a comprehensive set of wind events across the five-year simulation were compared to a theoretical cross-shore upwelling model depending only on wind stress, stratification and cross-shore bottom slope to identify the physical parameters that control upwelling. Upwelling accounted for approximately one-third of summer surface nitrate variance based on the PCA results. Modelled upwelling depth generally agreed with the theoretical prediction and was thus interpreted to depend primarily on wind stress and stratification. The deepest upwelling and strongest nitrate anomalies occurred in the northern Strait of Georgia, which is consistent with the presence of an along-axis stratification gradient due to the Fraser River. These results establish a direct link between climate forcing and the factors that determine upwelling in the Strait of Georgia, with strong implications for summer productivity in the region.Science, Faculty ofEarth, Ocean and Atmospheric Sciences, Department ofGraduat
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
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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