1,721,040 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
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
Environmental covariates of sablefish (Anoplopoma fimbria) and Pacific Ocean perch (Sebastes alutus) recruitment in the Gulf of Alaska
Full text linkThesis (M.S.) University of Alaska Fairbanks, 2014.The sablefish (Anoplopoma fimbria) and Pacific ocean perch (POP; Sebastes alutus) fisheries in the Gulf of Alaska (GOA) are both highly lucrative and variable. Determining environmental factors that drive variability in year class strength may improve their forecasts, leading to more effective management. Here we examine relationships between sablefish and POP recruitment and multiple environmental indices associated with circulation in the GOA. We used hierarchical cluster analysis to determine spatially and seasonally relevant scales for analyzing these relationships, a relatively novel approach that may be of use to similar studies. We used structural equation modeling to examine sequential relationships between large-scale climate variables, regional (eastern and western GOA) environmental variables, and recruitment using both hypothesis-testing and exploratory approaches. Exploratory analyses revealed that sablefish recruitment was positively related to July upwelling-favorable winds and negatively related to late winter freshwater discharge in the eastern gulf during age 1. POP recruitment was negatively related to June upwelling-favorable winds in both regions during ages 0 and 1 and positively related to late spring freshwater discharge during age 1. These results suggest that upwelling-favorable winds and freshwater discharge may affect recruitment of both species through productivity-related mechanisms, and may additionally affect POP recruitment through advection-related mechanisms. Targeted studies at the appropriate scales are needed to provide greater certainty in the potential mechanisms behind these relationships
Evaluation of growth and migration trends on the survival and recruitment of chinook salmon in Southeastern Alaska rivers
Full text linkThesis (M.S.) University of Alaska Fairbanks, 2017Highly variable recruitment and declines in productivity and abundance of Chinook Salmon Oncorhynchus tshawytscha have created economic and cultural hardships for communities throughout Alaska. Although pre- and post-smolt growth are important for determining brood-year (BY) survival and productivity for Pacific salmon through size-mediated mortality, these relationships remain unclear for Chinook Salmon. As a result, it is necessary to better understand the relationships between environmental and biological factors that influence freshwater and marine growth, smolt outmigrations, and recruitment success. This study used retrospective growth to identify the importance of annual growth in determining BY survival and recruitment, determine if growth dependency between growth zones was present, and examine growth differences among age classes for Chinook Salmon in the Chilkat (BYs 1985 - 2007) and Stikine (BYs 1991 - 1998 and 2000 - 2007) rivers. Biological and environmental factors were also assessed to determine their influence on freshwater smolt production, smolt outmigration, and marine survival. Greater first-year marine growth was correlated with higher BY total return and productivity for Chinook Salmon from the Chilkat River and higher BY marine survival for Chinook Salmon from the Stikine River. Daily smolt outmigration of Chilkat River Chinook Salmon was positively correlated to water temperature and negatively correlated to discharge (Deviance explained = 68.5%), while timing of the start of outmigration was influenced by nearshore sea surface temperatures (R² = 0.57) and timing of the mid and end points were positively related to smolt length (R² = 0.72 and 0.34, respectively). Freshwater smolt production was negatively correlated to parr length and fall discharge and positively correlated to spring temperature and discharge (R²adj= 0.52). Marine survival of Stikine River Chinook Salmon was significantly related to smolt size (R² = 0.26), while Chilkat River Chinook Salmon were positively related to migration timing and smolt length and negatively related to discharge (R² = 0.5). These results support the importance of the early marine period in determining year-class strength and highlight the variation in mechanisms that influence recruitment success of Chinook Salmon stocks
Examination of saffron cod (Eleginus gracilis) population genetic structure
Full text linkThesis (M.S.) University of Alaska Fairbanks, 2019The Saffron Cod (Eleginus gracilis) is an abundant forage fish that inhabits the coastlines of the north Pacific and Arctic oceans. We examined Saffron Cod population genetic structure to provide a reference baseline in anticipation of human and climate-change alterations of the Arctic environment. Nine microsatellites were designed to describe the genetic compositions of and variation among 40 collections of Saffron Cod from four regions (northwestern Alaska, Gulf of Alaska, Sea of Okhotsk, and Gulf of Anadyr). The northwestern Alaska collections (Bering Sea, Norton Sound, and Chukchi Sea) exhibited little genetic divergence. The Gulf of Anadyr collection differed from other regions but was most similar to those of the northwestern Alaska region. The two collections within the Sea of Okhotsk (Sakhalin Island and Hokkaido Island) differed genetically, but not to the extent they did from other regions. The collections from the Gulf of Alaska (Kodiak Island and Prince William Sound) comprised a lineage that was distinct from all of the other collections, including the geographically adjacent northwestern Alaska collections. The absence of genetic structure among northwestern Alaska collections probably reflects their recent expansion into previously unavailable habitat that became available after the Last Glacial Maximum (~16,000 years ago). The divergence of the Gulf of Alaska lineage may have resulted from recurrent episodes of isolation from previous glaciations.Bureau of Ocean Energy Managemen
Feeding ecology and movement patterns of juvenile sablefish in coastal Southeast Alaska
Full text linkThesis (M.S.) University of Alaska Fairbanks, 2014Sablefish, Anoplopoma fimbria, is a commercially valuable groundfish species undergoing population declines in the Gulf of Alaska and Bering Sea. This study assessed the role of juvenile sablefish as consumers in coastal Southeast Alaska (St. John Baptist Bay, Baranof Island, Alaska; SJBB) to better understand their use of habitat and food resources during their early life history. Specifically, the diet of juvenile sablefish was described for multiple seasons (summer and fall) and years (2012 and 2013) from analysis of stomach contents recovered using gastric lavage. Sablefish ate a wide variety of prey taxa, and the most important prey groups were Pacific herring, smelts, and scavenged salmon remains. Diet differed between seasons and years, and scavenging of salmon carcasses occurred during fall sampling periods, revealing the ability of sablefish to capitalize on pulsed, high energy prey. We further explored habitat use by juvenile sablefish within SJBB by analyzing their vertical movement patterns using acoustic telemetry data. Sablefish that were frequently detected remained predominately near the bottom, but all fish remaining in range of the acoustic receivers made short excursions into shallower water. Generalized linear mixed models were used to determine the relationship between excursion frequency and daylight and tidal cycles. The excursion frequency was highest during slack and flood stages and at dawn and may be linked to foraging. Together, these findings suggest that juvenile sablefish may maximize their growth by accessing high energy pelagic and benthic prey while remaining on the bottom for the majority of time, potentially decreasing risk of predation
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