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Middle and Late Weichselian paraglacial and subglacial ervironments in the coastal plains of western Latvia
Get PDFTomas Saks
Promocijas darbs: „Vidus Vislas un Vēlās Vislas laika
paraglaciālie un zemledāja vides apstākļi Rietumlatvijas
piekrastes līdzenumos”
Anotācija
Šajā pētījumā ir prezentēti Baltijas jūras stāvkrastu glaciotektonisko struktūru
kartēšanas, glaciālo reljefa formu dešifrēšanas rezultāti un precizēta Rietumlatvijas
pleistocēna slāņkopas augšējās daļas hronostratigrāfjija. Zem morēnas smilšainajos
nogulumos ir veikti 13 jauni OSL datējumi.
Glaciotektonisko struktūru kartēšanas rezultāti ļauj izšķirt trīs dažādus ledāja
gultnes deformācijas veidus: (I) Atsegumu posmi, kas atbilst ledus mēļu centrālajai
zonai, un kuriem ir raksturīgs mozaīkveida zemledāja deformācijas un morēnas
akrēcijas sadalījums. (II) Atsegumu posmi, kas raksturojas ar kompresijas
deformācijas struktūru sistēmu. Šie atsegumu posmi atbilst ledus mēļu marginālajām
zonām, un ir šķērsgriezums bīdes sānu morēnām. (III) Atsegumu posmi, kuros nav
zemledāja deformācijas pazīmes, kas ataino stagnanta ledāja apstākļus.
Apriķu ledāja mēles gultnes dešifrēšanas rezultāti liecina, ka glaciālās reljefa
formas un gultnes topogrāfija mainās strauji, līdz ar pamatiežu virsmas dziļuma un
sastāva izmaiņām.
OSL datēšanas rezultāti liecina par datētās slāņkopas uzkrāšanās laiku Vidus
Vislas laikmetā, kas ļauj pārskatīt Rietumlatvijas pleistocēna slāņkopas augšējās daļas
hronostratigrāfiju.
Atslēgas vārdi: Diapīri, drumlini, sānu bīdes morēnas, OSL datējumi, Baltijas ledus
lielplūsma.
Latvijas Universitāte
19.06.2010Tomas Saks
Promocijas darbs: „Middle and Late Weichselian paraglacial
and subglacial environments in the coastal plains of western
Latvia”
Abstract
In this thesis are presented results of: glacial geology and glaciotectonics of
the Baltic sea coastal bluffs, mapping of the glacial landscape and established
chronostratigraphy of the upper part of western Latvia Pleistocene sedimentary
sequence.
Results from the glaciotectonic structure reconstructions allow to differentiate
three distinct subglacial deformation environments: (I) diapiric flow of the subglacial
sediments induced by the changes of pore water pressure; (II) unidirectional
compression deformation of the subglacial sediments; (III) areas of no subglacial
deformation, resembling frozen to the bed ice conditions.
Glacial bedform mapping results of the Apriķi glacial tongue bed allow to
conclude that glacial landscape is changing abruptly along with the changes in
bedrock composition and depth.
Obtained OSL dates of the sandy sequence below upper till suggest Middle
Weichselian age which allows reinterpreting the chronostratigraphy of the western
Latvia Pleistocene sedimentary sequence upper part.
Key words: Diapirs, drumlins, margin shear moraines, OSL dates, Baltic Ice Stream.
Latvijas Universitāte
19.06.201
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe 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
Get PDF“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
Get PDFWe 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
Get PDFWe 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
Annual mass balance time series for the Tien Shan and Pamir from 2000 to 2018
No full textAnnual mass time series for Central Asia were calculated using the transient snowline position and its rate of change during the ablation season to constrain the winter snow accumulation and the melt parameters of a distributed accumulation and temperature-index model for each glacier and year individually. This method is based on Barandun et al., 2018, TC and was regionally applied in Barandun et al., accepted, GRL (GRL mannuscript identifier: 2020GL092084). The transient snowline on a glacier marks the transition between the ice and snow surface, thus approximates the zero-mass balance line of the glacier during the ablation season. The snowline is hence a proxy for the surface mass balance. Automatic snowline mapping at the scale of individual glaciers on over 3,000 Landsat surface reflectance products provided a total of 255,000 snowlines from 2000 to 2018 for the region. As a second-order calibration, we calculated geodetic mass balances using Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) scenes and High Mountain Asia Digital Elevation Models (HMA DEMs).
Our mass balance calculations, tied to transient snowline observations, provided annual mass balance time series for 1,222 (61%) glaciers greater than 2km2 located in the Tien Shan and Pamir. Details on the methods can be found in:
Barandun, Martina, Matthias Huss, Ryskul Usubaliev, Erlan Azisov, Etienne Berthier, Andreas Kääb, Tobias Bolch, and Martin Hoelzle. "Multi-decadal mass balance series of three Kyrgyz glaciers inferred from modelling constrained with repeated snow line observations." The Cryosphere 12, no. 6 (2018): 1899-1919.
These annual time series have been presented in:
Barandun, Martina, Eric Pohl, Kathrin Naegeli, Robert McNabb, Matthias Huss, Etienne Berthier, Tomas Saks and Martin Hoelzle. "Hot spots of glacier mass balance variability in Central Asia". Geophysical Research Letters, accepted (GRL mannuscript identifier: 2020GL092084)
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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