1,721,111 research outputs found
Relationship between air-rock-water temperatures in karst caves and surface temperatures
Full text linkIn karst caves air-rock-water temperatures are rather constant over time compared to the surface considerable thermal variations. The significant differences between the outside air temperatures and the in-depth ones, environmental parameters and karst system morphology, trigger the air circulation in the fracture networks. Air has a very low thermal inertia, therefore, if still, it quickly reaches a sort of equilibrium condition with the rock, assuming the rock temperature in absence of significant circulations. The greater thermal exchanges take place near the cave entrances, conditioned mainly by the speed of the incoming air flows. Into depth, temperature of the infiltration waters plays a dominant role in subtracting heat from the limestone masses, which have a lower temperature than the other rocks (Badino 1995).
To better understand these processes, the Paleolab of Politecnico di Torino began a series of research through the installation of data loggers for air-rock-water temperatures monitoring in karst caves of southern Piedmont, Italy, characterized by very different environmental conditions. In collaboration with Arpa Piemonte, part of the project concerned the monitoring of cavities characterized by the presence of underground glaciers showed a rapid reduction in the last decade, linked to the increase in surface temperatures (Vigna & Paro 2019). In collaboration with S.O. Bossea C.A.I., another part of the project involved the installation of over 50 air-rock-water temperature probes at the "Giovanni Badino" Climatological Research Centre to examine the relationships between surface and in-depth temperature variations. Finally, in collaboration with the Speleo Club Tanaro, the third project concerns the temperatures monitoring of caves characterized by considerable air flows, for examine at different distances from the entrances the relationships between the air and the rock temperatures induced by these air circulations.
Badino G. (1995). Fisica del clima sotterraneo. Istituto Italiano di Speleologia, 137 pp.
Vigna B. & Paro L. (2019)
Anthropogenic impact assessment in show caves through environmental parameters monitoring
Full text linkAs part of the national project PRIN SHOWCAVE, aimed at the study of the anthropogenic impact in show caves, environmental parameters were monitored in three important cavities (Toirano and Borgio Verezzi caves in Liguria, and Bossea cave in Piedmont, Italy). Air-water-rock temperatures and CO2 air concentrations were detected every 10 minutes, groundwater level variations with hourly intervals.
Air temperature variations are significant not only to assess the tourist passage and light impacts, but also because they allow to understand the air circulation in the cavities. By placing temperature probes outside and at the entrances of the caves it is easy to observe periods with evident variations related to daily thermal fluctuations (intake phase). In the blowing phase, air temperature values remain rather constant over time, flowing air coming from deep areas of the cavity, characterized by a remarkable constant thermal values.
The three examined caves showed different situations. Bossea cave has a unique entrance (one-entrance circulation), and is characterized by several convective cells related to the cave morphology and the air cooling due to the inner collector. Toirano caves are two cavities (Bàsura and S. Lucia Inf. caves) connected through an artificial tunnel. The difference between the high and low entrances is about 20 m with a mild air circulation (multi-entrance cave), highlighted by the different temperature values detected at the two entrances. Borgio Verezzi cave has four entrances with an elevation gain of few meters which guarantees a mild air circulation (multi-entrance cave).
The monitoring of the CO2 values carried out in the cavities showed a daily impact linked to the tourist passage, with an obvious temporary increases related to the number of visitors. However, the air circulation inside all monitored cavities allowes a decrease in CO2 concentrations. Moreover, collected data highlighted a significant CO2 air concentration of natural origin in each monitored cave. In Toirano caves, about 8,000 ppm of CO2 were detected in a not-touristic area, coming from the deep karst networks. In the other two cavities, part of the CO2 come from the depressurization of the waters circulating in the saturated network of the karst system, near the tourist paths.
Thanks to the data collected in three consecutive years, it was possible to evaluate a rather reduced anthropogenic impact in the three show caves
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
Structural control on karst water circulation and speleogenesis in a lithological contact zone: The Bossea cave system (Western Alps, Italy)
No full textGeological surveys, structural mapping, and thin section analysis helped to unravel the speleogenesis and water
circulation in the Bossea cave (Northern Italy), an unconventional karst systemat the contact between carbonates
and underlying insoluble rocks. The surveys within the cave and in the surrounding surface outcrops revealed a
complex structural setting caused by the coupling of lithological-mechanical heterogeneities with two major regional
left-lateral ESE-WNWstrike-slip faults. Transpression associated with the faults led to a disharmonic deformation,
accommodated by a detachment surface, between the buckled basement meta-volcanics and the
disharmonically-folded-marble sequence laying on top. Low-angle shear zones, recumbent or drag folds, and
small stacks of duplexes are localized next to this detachment. The preferential pathways for water circulation
inside the vadose zone are the folded bedding interfaces in the meta-carbonate sequence. Fracture clusters at
slipping bed terminations, on the other hand, provide through-sequence connectivity. Once underground stream
water flow reached the cataclastic and highly deformed meta-volcanics of the detachment core and damage
zones, erosion started, removing large volumes of rocks. The downward erosion of the Permian basement
rocks caused gravitational instability and subsequent roof collapses, aided by structural control in the damage
zone above the detachment surface (slip surfaces in between duplexes or drag folds). This gravitational instability
ultimately led to the formation of the giant halls that are characteristic of the downstreampart of the Bossea cave
Recent morphological evolution and slope instability in a hilly area of piedmont (north italy)
No full textAssessment of water table aquifer intrinsic vulnerability and evaluation of groundwater quality in an area including the Ticino Valley Natural Park Valley (NO, Piemonte, Italy)
No full textVariations 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
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