1,721,002 research outputs found
Digital elevation model and orthophoto of Freya Glacier 2021
No full textIn July 2021 we surveyed the surface of Freya Glacier (Northeast Greenland). On 29th and 31st July 2021, we used a UAV (DJI Phantom 4 RTK) to obtain overlapping image series of the glacier surface. On 29th July, we photographed 80% of the glacier surface (lower part) and finished the drone flights on 31st of July. On 28th and 29th of July 2021, we surveyed ~100 mainly artificial GCPs on the glacier surface using a differential GNSS receiver and a base station. During the survey, surface ablation between 28th and 31st July was less than 0.2 m. Using a structure from motion approach, we could reconstruct 95% of the glacier surface with a very high level of detail and vertical accuracy. The DEM of the glacier has a horizontal resolution of 1m and the elevation has an RMSE at the check points of 0.18 m. The DEM and the orthofoto are projected to UTM (zone 27N, epsg:32627) and to orthometric heights (egm96). The data also contain the glacier outline of Freya Glacier in 2021 as a shapefile
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
Predicting Runoff for a Drinking Water Catchment in Southwest Greenland
No full textEfterhånden som smeltevandsafstrømningen fra Grønlands gletsjere og iskapper stiger, er der et øget behov for at kvantificere denne afstrømning, for at forbedre forståelsen og give et mere nøjagtigt estimat af bidraget til den globale havniveaustigning, ændringer i havstrømme på grund af en faldende saltkoncentration og potentialet for udnyttelse af naturressourcer.
12 % af verdens gletsjere og iskapper findes langs Grønlands periferi, hvor langt størstedelen
ligger i oplande med delvist isdække, uden målinger og vejrstationer til at
kunne beregne smeltevandsafstrømningen. Klimamodeller har derfor en nøglerolle i at simulere og estimere mængden af smeltevand i fremtiden. Generelle cirkulationsmodeller og regionale klimamodeller har for lav opløsning til at fange terrænvariationerne i oplande med delvist isdække og kan resultere unøjagtigheder ved beregning af smeltevandsafstrømninger
Denne undersøgelse fremhæver disse unøjagtigheder ved at præsentere styrker og svagheder
ved flere klimamodeller; undersøgelsen validerer regionale klimamodeller på lokal skala, for at opnå afstrømning af smeltevand i mindre afvandingsområder i Grønland. Statistisk nedskalering fra 11 km til 30 m blev anvendt som et værktøj til at forbedre opløsningen på lufttemperatur og nedbørsdata i oplande med delvist isdække. Den samlede månedlige afstrømning i et afvandingsområde, i Vestgrønland, blev forudsagt frem til 2060 ved hjælp af en positiv gradedagsmodel. Med en beregnet smeltevandsafstrømning, der topper i 2040, konkluderer denne undersøgelse, at mængden af smeltevand er tilstrækkelig til kommerciel udnyttelse i de næste 40 år
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
Predicting Runoff for a Drinking Water Catchment in Southwest Greenland
Full text linkEfterhånden som smeltevandsafstrømningen fra Grønlands gletsjere og iskapper stiger, er der et øget behov for at kvantificere denne afstrømning, for at forbedre forståelsen og give et mere nøjagtigt estimat af bidraget til den globale havniveaustigning, ændringer i havstrømme på grund af en faldende saltkoncentration og potentialet for udnyttelse af naturressourcer.
12 % af verdens gletsjere og iskapper findes langs Grønlands periferi, hvor langt størstedelen
ligger i oplande med delvist isdække, uden målinger og vejrstationer til at
kunne beregne smeltevandsafstrømningen. Klimamodeller har derfor en nøglerolle i at simulere og estimere mængden af smeltevand i fremtiden. Generelle cirkulationsmodeller og regionale klimamodeller har for lav opløsning til at fange terrænvariationerne i oplande med delvist isdække og kan resultere unøjagtigheder ved beregning af smeltevandsafstrømninger
Denne undersøgelse fremhæver disse unøjagtigheder ved at præsentere styrker og svagheder
ved flere klimamodeller; undersøgelsen validerer regionale klimamodeller på lokal skala, for at opnå afstrømning af smeltevand i mindre afvandingsområder i Grønland. Statistisk nedskalering fra 11 km til 30 m blev anvendt som et værktøj til at forbedre opløsningen på lufttemperatur og nedbørsdata i oplande med delvist isdække. Den samlede månedlige afstrømning i et afvandingsområde, i Vestgrønland, blev forudsagt frem til 2060 ved hjælp af en positiv gradedagsmodel. Med en beregnet smeltevandsafstrømning, der topper i 2040, konkluderer denne undersøgelse, at mængden af smeltevand er tilstrækkelig til kommerciel udnyttelse i de næste 40 år.As meltwater runoff increases from local glaciers and ice caps in Greenland, there is motivation to better quantify this runoff to improve the understanding and more accurately estimate its contribution to global sea level rise, dynamics of seawater freshening on ocean currents and gauging the potential for natural resource exploitation. Twelve percent of the world’s glaciers and ice caps are contained around the periphery of Greenland and the vast majority lies in partially glaciated basins that are ungauged and without weather stations, thereby, resulting in a gap of available data required to calculate meltwater runoff in these catchment areas. This then leaves climate models as the key method to simulate and predict the amount of future runoff produced. Currently, calculating meltwater discharge with coarse resolution general circulation models or even regional climate models, does not completely capture the intricacies of the terrain in a partially glaciated basin and can create large potential for error. This study highlights these errors by presenting the strengths and shortcomings of several global and regional climate models on local scales on glacier catchments, with the aim to predict runoff more accurately. This evaluation has shown that none of the climate models adequately captures either spatial or temporal variability in air temperature and meltwater production. Statistical downscaling of climate grids, from 11 kms to 30 m, was applied as a tool to better resolve air temperature and precipitation in partially glaciated basins but was unable to counteract inaccuracies leaking from climate models into local estimates. The total monthly runoff was predicted, out to 2060, using a positive degree day model that focused on one drinking water catchment in Southwest Greenland, with a discharged peak in 2040. The catchment is therefore assessed as being able to provide a continuous source of drinking water for export throughout the next 40 years
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