1,721,320 research outputs found
Snow gliding and glide-snow avalanches: recent outcomes from two experimental test sites in Aosta Valley (northwestern Italian Alps)
Full text linkSnow gliding and glide-snow avalanches are gaining importance among scientists as global warming might induce conditions favourable to those phenomena. Our aim is to analyse such processes with a particular focus on the potential driving factors associated with the soil conditions. We equipped two experimental test sites in the Aosta Valley region (NW Italy) with glide-snow shoes, temperature and volumetric liquid water content (VLWC) sensors in the soil and in the basal snowpack layer; snow and weather parameters were also collected by automatic weather stations and at manual snow measuring sites. In the two monitoring seasons 2013–2014 and 2014–2015 we registered nine glide-snow avalanches, two cold and seven warm events, which were characterized by different snow and soil conditions. In the only warm glide-snow avalanche event, which presented a continuous gliding before, the daily glide rate showed a significant exponential relationship with the soil VLWC. We also found, though without a general trend, that gliding and non-gliding periods (either considering warm and cold periods separately or together) were characterized by significantly different predisposing factors. This study contributes to the assessment of the importance of soil VLWC, which seems to be one of the most important driving factors for gliding processes. Therefore, it supports the need, already suggested by other scientists, for analysing such processes with an interdisciplinary approach which integrates snow and soil sciences
SNOW-AVALANCHE AND CLIMATIC CONDITIONS IN THE LIGURIAN SKI RESORTS (NW-ITALY)
Full text linkLiguria Region is characterized by a 240 km-long coastal arc, and a largely mountainous territory. Consequently, its characteristic and famous Mediterranean-type climate is far from being uniform. Climatic diversity of Liguria reflects some fundamental morphological factors, such as southern exposures and the presence of a major mountain ridge with suitable climatic conditions for winter sports. Nevertheless, the permanence and stability of snow on the ground is related to local factors, such as the prevalent southern aspect, slope steepness, air temperature and wind intensity. The highest Ligurian peak is the Saccarello Mount (2200 m) at the borders with Piemonte and the French Department of the Alpes Maritimes, while the highest mountain in the Ligurian Apennines is the Maggiorasca Mount (1804 m). Near these areas there are two "historical" ski resorts established in the mid-60s: Santo Stefano d'Aveto, bordering the ski areas of Emilia-Romagna, and Monesi di Triora to the West, in the province of Imperia; both resorts have been subject to significant investment in the development of tourist activities and accommodation. The unique climatic conditions of Liguria and the established trends in climate require careful assessment of avalanche hazard, considering the increased flow of tourists and the poor perception of the associated risk in a region traditionally linked to "marine" leisure activities. During 2011, an avalanche in Santo Stefano d'Aveto caused the loss of a human life. The paper presents a preliminary contribution aimed at assessing avalanche susceptibility in the two ski areas of Liguria: starting from the analysis of historical avalanches, several parameters have been analyzed, such as hazardous nature of the terrain, the weather and snow conditions and the interaction with human activities and infrastructures
Integration of upward GPR and water content reflectometry to monitor snow properties
No full textWe adopt upward ground-penetrating radar (up-GPR) and water content reflectometry sensors to monitor the seasonal behaviour of snow density. Upward ground-penetrating radar permitted to observe at a single fixed station the time-lapse response of the electromagnetic signal at the main frequency of 1500 MHz, with the antenna radiating upward from the soil toward the snow surface. Measurements have been performed in a test site on Italian Alps (at an elevation of about 2100 m above sea level) during the 2014–2015 winter season at an interval of 30 minutes. The data processing of radar data involved the travel-time picking and the conversion into snow depth and density. Water content reflectometry measurements have been useful in order to calibrate the radar response and retrieve information on the presence of liquid water content. The integration of upward ground-penetrating radar and water content reflectometry technology allows us to infer snow high and layering, snow density changes during the winter season, and a preliminary estimate of the liquid water content. For snow in dry condition, we are able to estimate density values through mixing rules or polynomial formula. Snow density varies during the season in a range between 250 kg/m3 and 450 kg/m3; the results are in good agreement with the results of the ground truth. For snow in wet condition, the residuals of the electrical permittivity, after a trend removal on the original water content reflectometry data, permitted to estimate liquid water content in the range between 3% and 5%, during some periods of the winter season, according to warmer climate condition. Snow layering and densification processes are monitored by the response of upward groundpenetrating radar: fast phenomena such as wetting front infiltration can be also pointed out even if they appear challenging if other observations are not available (e.g., monitoring with water content reflectometry)
Editorial
Full text linkThe present Special Issue entitled “Italian Long-Term Ecological Research for understanding ecosystem diversity and functioning. Case studies from aquatic, terrestrial and transitional domains” is the first published collection of studies performed at LTER-Italy sites which address the diversity and dynamics of ecosystems in different domains in responses to natural and anthropogenic forcing
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
Soil variability in mountain areas
Full text linkThe high spatial variability of soils is a relevant issue at local and global scales, and determines the complexity of soil ecosystem functions and services. This variability derives from strong dependencies of soil ecosystems on parent materials, climate, relief and biosphere, including human impact. Although present in all environments, the interactions of soils with these forming factors are particularly striking in mountain areas
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
Microsite manipulation in lowland oak forest restoration results in indirect effects on acorn predation
Full text link- …
