1,721,027 research outputs found
Recent (1975-2003) changes in the Miage debris-covered glacier tongue (Mont Blanc, Italy) from analysis of aerial photos and maps
No full textABSTRACT: DIOLAIUTI G., D’AGATA C., MEAZZA A., ZANUTTA A. &
SMIRAGLIA C., Recent (1975-2003) changes in the Miage debris-covered
glacier tongue (Mont Blanc, Italy) from analysis of aerial photos and maps.
(IT ISSN 0391-9838, 2009).
The present study aims at identifying any changes in volume and
thickness of the Miage Glacier tongue (Mont Blanc Massif, Italy) during
the period 1975-2003. The Miage glacier developed the largest part of its
debris cover over the last century, now found mostly between the glacier
terminus (about 1850 m a.s.l.) and the upper ablation tongue (c. 2400 m
a.s.l.) on a surface area of c. 4 km2. The period examined (1975-2003) addresses
climate conditions which were glacier-favourable (around the
1980s), as well as glacier-unfavourable (since the early to mid-1990s),
thus contributing to an understanding of the behaviour of debris covered
glaciers under a changing climate.
The analysis was based on the comparison between digital elevation
models (DEMs), derived from historical records, specifically maps
(1975; scale 1:10,000) and photogrammetric surveys (1991 and 2003, scale
1:15,000). The results show a general glacier volume loss (–16.640 x 106 m3)
from 1975 to 2003; nevertheless if we focus on the two time sub-windows
(i.e.: 1975-1991 and 1991-2003) opposite trends are found: in the period
1975-1991 the volume variation of the Miage Glacier was about +19.25x106
m3, in the period 1991-2003, on the other hand, a volume decrease of about
–36.2x106 m3 occurred. Analysis shows that volume changes were strongly
influenced by the supraglacial debris coverage which on Miage glacier
tongue modulates the magnitude and rates of buried ice ablation
Itinerari naturalistici al Passo Gavia. Cambiamento climatico ed evoluzione dei paesaggi alpini
No full textIl libro descrive le principali caratteristiche degli ambienti naturali di alta montagna con particolare riferimento alla criosfera (permafrost e ghiaccai) ed alla vegetazione. E' incluso anche un atlante fotografico a colori su alcune specie di piante alpine. Inoltre, sono descritti due itinerari naturalistico-didattici al Passo Gavia realizzati in collaborazione e per conto del Parco Nazionale dello Stelvi
First attempt to classify and inventory local or “alpine” glaciers in Northern Victoria Land (Antarctica).
No full textImpatti inattesi ed accelerati del cambiamento climatico sulla vegetazione alpina e periglaciale
No full textL'articolo illustra i principali impatti del cambiamento climatico sulla vegetazione alpina di alta quota con particolare riferimento agli ambienti proglaciali e periglacial
Dry calving processes at the ice cliff of Strandline Glacier, northern Victoria Land, Antarctica
Full text linkThis paper describes seasonal variations on Strandline Glacier, Terra Nova Bay, northern Victoria Land, Antarctica, obtained from measurements during two field campaigns (2000/01 and 2002/03). By applying different methodologies and techniques, it was possible to calculate summer changes in thickness (mean decrease over the whole glacier surface of 0.04 m w.e.) and in volume (decrease of 352 m(3) at the terminus). This serves to identify and quantify the processes responsible for these variations (e.g. melting, evaporation, wind erosion/deposition and calving) and to understand the energy transfers at the glacier-air interface. One particular feature of the glacier is the presence of an ice cliff at the terminus, which causes ablation owing to dry calving. This process brought about a summer retreat rate of 1 m week(-1) in the central part of the front during the study period. Qualitative observations carried out during previous field campaigns and quantitative analysis performed during the last two expeditions have provided an understanding of the mechanism underlying the ablation processes, thus confirming the available literature on this topic
Mass balance and energy balance at Strandline Glacier (Terra Nova Bay, Antarctica): Methods and preliminary results
No full text
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
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