1,721,137 research outputs found
The Role of the Minor Hydrographic System in Increasing the Ecological Network
Full text linkThis contribution describes the definition of the structure of the local ecological network. It was carried out as part of the support activities for the construc-tion of the new urban plan of Mappano (Turin, Italy). The knowledge of the minor hydrographic system in Mappano allowed the construction of the structural map of the local ecological network, which contemplates the structural elements of the network (primary ecological network), the contiguous portions to the structural elements (areas with ecological functionality areas where it is a priority to intervene to increase ecological network), the areas of possible expansion of the network, i.e., areas with residual ecological functionality. However, there it is possible to carry out interven-tions useful for the protection of habitats and species of interest for conservation of biodiversity. Peripheral strips and connecting corridors, consisting of minor water canals, have therefore made it possible to better define the areas of possible expansion of the network: wetlands and marshes, in these relevant areas, represent stepping-stones of fundamental importance for rest and reproduction of many species and which need to be safeguarded in the design of the new local urban plan
Temporal variability of soil management effects on soil hydrological properties, runoff and erosion at the field scale in a hillslope vineyard, North-West Italy
Full text linkSoil management in vineyard inter-rows has a great influence on soil hydraulic conductivity and bulk density, and, consequently, on runoff and soil erosion processes at the field scale. The maintenance of bare soil in vineyard inter-rows with tillage, as well as the tractor traffic, are known to expose the soil to
compaction, reduction of soil water holding capacity and increase of runoff and erosion. The use of grass cover is one of the most common and effective practices in order to reduce such threats. It is therefore important to relate rainfall characteristics, soil properties and response in terms of runoff and soil
erosion, from yearly to seasonal and to single event temporal scales. The objective of this work is to quantify the temporal variability of the effects of two different kind of inter-row management on soil hydrological properties, runoff and erosion in vineyards. For this reason two vineyard field-scale plots in
the Alto Monferrato vine-growing area (Piedmont, NW Italy) were monitored in two years. The inter-rows were managed with conventional tillage (CT) and grass cover (GC), respectively. Fifteen series of infiltration tests were carried out during a 2-year period of observation (October 2012 to November
2014). In order to take into account the effect of tractors traffic, the tests were done on the track, and outside the track. Furthermore, a dataset of 29 rainfall-runoff events covering a wide range of topsoil characteristics was collected in the two plots, along with soil water content and runoff discharge monitoring, and determination of sediment yield in case of erosive events. An optical disdrometer installed in the plots provided also 1-min rainfall intensity data. In summer, just one month after tillage,
CT soil showed very low hydraulic conductivity, so storms were able to cause Hortonian runoff and soil losses up to 5.7 Mg ha1. In autumn and winter very high saturation-excess runoff was observed in CT, that reached 83% of the precipitation. Runoff in the grass cover plot was mainly due to saturation of the
topsoil, and the annual reduction of runoff in the GC plot was about 63%. Soil erosion up to 1.2 Mg ha1 in a single event was observed in the GC vineyard in winter. In each year of observation, most of the erosion occurred during a single event, while the total annual erosion was up to 9 times higher in the CT
treatment than in the GC
Evaluation of Turbulent Fluxes on a mountain slope
Full text linkStudies about turbulent exchanges, momentum and mass transfer and energy balance on mountain slopes allow a better comprehension of the interactions between soil and atmosphere in complex orography. In addition, if long periods of observations are considered, the evolution of energy and mass fluxes can be derived. This is useful
for model delicate ecosystems such as in the highlands. Furthermore, the study on carbon dioxide fluxes can be related to the increase of greenhouse gas. The eddy-covariance technique has some critical points: one of the most important is related to the relative uncertainty in the fluxes estimation when there are bad weather or low-wind and nocturnal conditions. Our aim is divided into two parts: in the first one, the meandering was explored. In the second part, we compared two approaches, the planar fit and the double rotation techniques for the computation of turbulent fluxes. Because of the high number of low-wind speed conditions (LWS), we investigated the “meandering”: in LWS conditions, wind speed components and scalars such as temperature can show oscillations visible in the
auto-correlation function of the signals. In these cases, turbulent fluxes estimation may be difficult. We analysed 11 months of data collected at 10 Hz, considering a 1-hour time scale, with the identification of surface-layer parameters. Meandering phenomenon was explored following the works of Mortarini et al. (2013, 2015). We
evaluated also the impact of clear-sky conditions on our data. We observed the validity of the formula for spectral analysis proposed in the aforementioned papers in most part of the analysed hours. Meandering conditions occur in 305 hours over more than 8000, especially during winter and night, although there are diurnal episodes. Meteorological conditions seem to play some role on the local phenomena because, although no certain relationship between stability and meandering parameters was found, the sky was cloudy in most part of meandering hours. In the second part, 30-minutes turbulent fluxes (sensible heat flux, latent heat flux and mass fluxes of water vapour and carbon dioxide) were determined using planar fit and double rotation techniques and the eddy-covariance technique use was tested for our site having a slope of about 26. Then, computation of the energy balance was done. We made comparisons between estimated and measured data and considerations on sensible and latent heat fluxes, then energy and mass fluxes and net radiation were computed also at the daily scale. We found that anemometer rotations improve robustness of computation and the difference between planar fit and double rotation is not so high in fluxes computations. Planar fit seems to give more reliable values. Considering the ground heat flux, G, we obtained a better approximation of energy balance. In particular, the computation of the energy balance ratio (EBR) showed that in general the balance is better during the daytime, while the seasons in which the energy balance is nearer to closure are summer and autumn
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
Year-round variability of field-saturated hydraulic conductivity and runoff in tilled and grassed vineyards
Full text linkThe soil management adopted in vineyard inter-rows has a great influence on soil hydraulic properties, and, consequently, on runoff at the field scale. Conventional management with tillage is adopted by vine-growers to improve the soil water recharge during winter. Nevertheless, this practice is known to increase runoff and soil erosion in steep areas, especially in mechanized vineyards, thus grass cover is adopted to reduce these negative impacts. The year-round values of field-saturated hydraulic conductivity and of the field-scale runoff were measured in vineyard plots from November, 2012 to March, 2016 in the Alto Monferrato vine-growing area (Piedmont, NW Italy). Field-saturated hydraulic conductivity values were obtained by 110 infiltration measurements. The tests were carried out by adopting the Simplified Falling Head methodology in two adjacent vineyards plots, where inter-rows were managed with conventional tillage (CT) and grass cover (GC), respectively. The runoff, the soil temperature and the soil water content in the two plots have also been recorded. As it was expected, the tillage increased the field-saturated hydraulic conductivity with respect to the plot with permanent grass cover. However, this effect was only temporary, since a decrease in field-saturated hydraulic conductivity was observed as a consequence of cumulative precipitation and tractor passages after the tillage operations. The field-saturated hydraulic conductivity ranged between 9 and 9119 mm h-1 in the tilled plot and between 4 and 1775 mm h-1 in the plot with grass cover. The response of the plots to precipitation events, in terms of runoff also varied considerably. Generally, during most of the events, the runoff in the tilled plot resulted higher (up to nearly 20 times) than in the grassed one. The grass cover was less effective in occasion of large precipitation events during the wet seasons than in other months
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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