1,720,969 research outputs found
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
Relationships between wetland ecotones and inshore water quality in the Ugandan coast of Lake Victoria
No full textMuch of the lake shore in Lake Victoria is covered by extensive wetlands, often dominated by dense papyrus stands that extend out over the lake waters. These wetlands, their extension and management play a role in the physical, chemical and biological conditions of the inshore waters. Continuous transects along 180 km of shoreline together with spatial grids of sampling sites in eight bays were performed in the Ugandan inshore waters in order to analyze the relationships between the wetland characteristics and water quality. Measurements of extension of the wetland ecotones, water temperature (T), pH, Secchi disk depth (SD), dissolved oxygen (DO), total nitrogen (TN), total phosphorous (TP), dissolved inorganic nitrogen (DIN), soluble reactive phosphorus (SRP) and chlorophyll-a (CHL) were made in each sampling area. Data of T, pH and DO collected during the transects showed that the water characteristics of the bays differ from the open shoreline. Moreover, the magnitude of these physical–chemical differences is strongly conditioned by the dimension of the bordering wetlands. Bays with extensive wetlands ecotones were characterized by cooler, more acidic and poorly oxygenated waters. TN : TP ratios and especially DIN : SRP ratios decreased with the wetland presence along the coastline, showing a higher probability of N limitation in the inshore waters where large wetlands are present. Results point to denitrification processes in the wetland ecotones as the cause of this trend. The distribution of CHL was found to be highest in the presence of two significant point loading sources: a river (in Katonga Bay) and a major population centre (Kampala, in Murchison Bay). The reduction of external P loading is shown as an important step in the management of the eutrophication process of Lake Victoria inshore waters
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
Characterization of the Ugandan inshore waters of Lake Victoria based on temperature-conductivity diagrams
No full textTemperature-conductivity diagrams are shown as a valid instrument to analyze the hydrographic structure of freshwater ecosystems, even along the surface waters. We put this method in practice in the Ugandan inshore waters of Lake Victoria. A complementary parameter (T-C anomaly) was used to differentiate between upland water intrusions. The relative value of the T-C anomaly provided information about the nature of the water intrusions and showed a considerable correlation with the biological characteristics of the water masses. The results indicated that the connections between catchment attributes, water characteristics, and biological community are quite direct in the inshore waters of Lake Victori
The role of wetlands in the chromophoric dissolved organic matter release and its relation to aquatic ecosystems optical properties. A case of study: Katonga and Bunjako Bays (Victoria Lake; Uganda)
No full textChromophoric Dissolved Organic Matter (CDOM) is an important component in freshwater and marine ecosystems
and plays direct and indirect role in biogeochemical cycles. CDOM originates from the degradation process of organic
materials, usually macrophytes and planktons. The present work examines the importance of wetland derived CDOM
on the optical and bio-optical properties of two bays of Lake Victoria (Uganda, Africa). This was achieved by determining
the attenuation and extinction coefficients of filtered and unfiltered water samples from two equatorial bays on the Ugandan
coastline of Lake Victoria. Katonga Bay is a wetland lined bay that receives water from the Katonga river, while Bunjako
Bay is an outer bay between Katonga Bay and Lake Victoria. The results showed that attenuation was highest in
Katonga Bay and the role ofCDOMis most dominant near the river inlet. The quantity and quality ofCDOMis extremely
different in the two bays: in Katonga Bay it is possible to hypothesize a terrestrial origin of CDOM (transported by the
wetland river). On the contrary, in Bunjako Bay, spectral measurements of absorption indicate a modified CDOM and/
or alternative CDOMsource. The terrestrial CDOMin Katonga Bay is more capable of absorbing harmful UV radiation
than theCDOMpresent in the Bunjako Bay. The resulting optical environment in the former bay presented a water column
with a very limited penetration of harmful UV radiation, while a higher penetration was observed in the Bunjako Bay
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
Variability in factors causing light attenuation in Lake Victoria
No full text1. The major optical components controlling the attenuation of photosynthetic available
radiation in nearshore areas of Lake Victoria (Uganda and Kenya) were examined and
their impact compared. It was found that chromophoric dissolved organic matter and
tripton play a dominating role in many nearshore areas, indicating that the coastal areas of
Lake Victoria cannot be considered as Case I waters.
2. Concentrations of chromophoric dissolved organic matter declined with distance from
the coast in an exponential manner indicating dilution and degradation of terrestrial
sources of organic matter rather than in situ production. The importance of tripton was
found to follow a similar pattern, while the relative importance of phytoplankton biomass
in overall attenuation of photosynthetic available radiation was found to increase with
distance from the coast. A specific attenuation coefficient for phytoplankton biomass was
determined (0.019 m2 mg Chl a)1).
3. Using a light limitation approach based on carrying capacity, it was possible to map
areas that are closer to being light limited. Light limitation appears to occur throughout
most bays and some coastal areas receiving catchment waters. This spatial information,
geographically referenced to bathymetric and catchment conditions, was utilized to
understand the importance of environmental conditions in limiting phytoplankton
biomass
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