1,720,987 research outputs found
Effects of the Wind on Some Weathering Features in Northern Victoria Land: an Experimental Approach
No full textBiotic and abiotic processes on granite weathering landforms in a cryotic environment, Northern Victoria Land, Antarctica
No full textA multidisciplinary study was carried out to understand the interactions between biotic and abiotic processes in granite weathering in ice-free areas of Northern Victoria Land, Antarctica. Examples of tafoni, pits and grooves were analyzed, focusing on their morphometry, infills, weathering rind types and vegetation patterns. Surface and subsurface temperatures and incoming radiation were measured to characterize microclimatic conditions. In addition, microscopic, SEM and X-ray diffraction analyses of granite were carried out. These analyses indicate that, under present conditions, mechanical weathering is the main process active in the formation of tafoni, which post-date pits and grooves. In these forms, granular disintegration is mainly induced by chasmoendolithic lichens, salt and thermal stress associated with the dilatation coefficients of different granite-forming minerals. The overall morphology of pits and grooves indicates that they originate from water erosion. In the former, mechanical weathering prevails, caused by epilithic lichens, by freeze-thaw events, and by salt, while only the first two processes are active in the grooves. The intensity of these processes is less effective than in tafoni and on the outer surfaces, suggesting that pits and grooves are inherited features, possibly generated in the same way as landforms occurring on granite in the humid tropics. Copyrigh
Climatic conditions and sporadic permafrost in the Maiella massif (Central Apennines, Italy).
No full textImpatti inattesi e accelerati del cambiamento climatico sulla vegetazione alpina e periglaciale
No full textTHE USE OF GPS MEASUREMENTS TO DEFINE THE SURFACE MORFOPHOLOGY OF A ROCK GLACIER. THE CASEOF FOSCAGNO ROCK GLACIER (ITALIAN CENTRAL ALPS)
No full textPossible Wind Effects on Weathering Pits in Some Coastal Test Sites in Victoria Land: an Experimental Approach
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
Seasonal effects on ice-wedge thermal variation in East Antarctica: a time series approach
No full textThis research aims at studying the thermal variation of ice wedges at various depths. In particular,
the analysis of ice-wedge top and bottom, ground surface and air temperatures are undertaken.
The active layer depth is calculated through seasons and years using hourly data at three sites in
northern Victoria Land: Baker Rocks, Boomerang Glacier and Mount Jackman. The recording
period is from 2004 to 2013 at Baker Rocks and Boomerang Glacier, and from 2006 to 2013 at
Mount Jackman.
Daily mean ground surface temperatures (DMGST) and daily mean air temperatures are highly
correlated at Baker Rocks (r2=0.96), Boomerang Glacier (r2 =0.95), and Mount Jackman (r2=0.92)
sites. This shows that the ground surface temperature at measurement sites responds strongly to
air temperature. Moreover, hourly ground surface temperature and DMGST are generally lower
than the air temperature in the winter season, which shows the absence of a significant snow
cover.
Standard deviations of the hourly temperature show that high temperature variability can exist
over one month, with higher variability in winter than in summer. Frequent and large temperature
fluctuations are common throughout winter with either a sharp drop or a rapid increase both in air
and ground surface temperature. Variations of 25°C to 30°C were recorded over periods of one to
four days.
The overall variability of temperatures is decomposed using spectral analysis in order to isolate
seasonal effects from cycles and long term trends. Moreover, spectral analysis is also applied to
the long term temperature data (26 years) from six automatic weather stations, located in northern
Victoria Land, to compare the temperature series recorded over different time spans and to
identify possible fitting trends. The time series approach in the frequency domain is quite new in
this field and it represents therefore the main contribution to the existing literature
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
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