1,720,960 research outputs found
Metodo di stima della fragilita’ intrinseca di habitats boschivi nei bacini di drenaggio di laghi vulcanici
No full textL’integrazione dell’ecologia ecosistemica con l’ecologia del paesaggio consentirà spiegazioni meccanicistiche di molti dei patterns osservati nei paesaggi. La propagazione delle perturbazioni è un esempio di come le caratteristiche strutturali e funzionali degli ecosistemi siano influenzate dall’eterogeneità spaziale del paesaggio. In questa ricerca si testa l’ipotesi di una stretta relazione tra eterogeneità ambientale del paesaggio o dei suoi sottoinsiemi e la probabilità di variazioni temporali dei
micropatches più omogenei. Parti di paesaggio sono state delimitate sulla base della varianza spaziale dell’indice NDVI in pixel di immagini satellitari Landsat riferite a tre anni 1987, 1992, 2000. La variazione temporale degli stessi pixel è stata stimata con la tecnica della Change Detection tramite il confronto delle immagini 1987, 1992, 2000. Lo studio ha evidenziato
che le aree più omogenee sono quelle che hanno subito maggiori cambiamenti nel tempo. Si discute questa relazione suggerendo che l’omogeneità può essere considerata una misura della fragilità intrinseca, non altrimenti misurabile, degli habitats relativamente a disturbi i cui effetti possono subire propagazioni
Modelling coastal processes by means of innovative integration of remote sensing time series analysis
Full text linkCoastal marine and inland landforms are dynamic systems undergoing adjustments in form at different time and space scales in response to varying conditions external to the system. Coastal emerged and nearshore areas, affected by short-term perturbations, return to their pre-disturbance morphology and generally reach a dynamic equilibrium. The objective of this research is to propose innovative remote sensing applications for monitoring and/or combination of existing ones to monitor specific coastal processes in order to quantify and model their time evolution. In particular, it shows which properties are the best proxy for remote sensing characterisation of nearshore coastal areas both emerged and submerged environments by combining multi-sensor spaceborne remote sensing (SAR and OPTICAL) to (a) produce deformation and spatiotemporal variations maps in coastal morphology with a special focus to point out the temporal subsidence evolution, (b) integrate inter and intra-annual change detection maps of vegetation into coastal morphology
Combined effects of acidification and competition on the feeding preference of a freshwater macroinvertebrate, Asellus aquaticus (Crustacea: Isopoda): a laboratory experiment.
No full textTo determine the combined effects of stream acidification and competition on the feeding preferences of benthic detritivores we compared, before and after sublethal acid exposure, lab-cultured populations of Asellus aquaticus reared either singly or with the closely related species Proasellus coxalis sensu lato in artificial channels. Both abiotic and biotic stressors reduced A. aquaticus density and affected its food intake. Whereas the presence of P. coxalis sensu lato increased the mass-specific ingestion rate and niche breadth of A. aquaticus according to optimal foraging theory, ingestion rate was reduced following acid exposure. Despite the increased variability in the consumption rate, variability of diet composition among individuals of A. aquaticus declined after acidification above all in the presence of the other species. Resource preferences changed, as a possible result of physiological accommodation to stress and/or selection of individuals that preferentially consumed the most processed plant detritus. The symmetry of niche overlap between the two species increased, strengthening the risk of competitive exclusion of A. aquaticus. The presence of the detritivores increased the buffering capacity of the artificial channels, reducing the rate at which the temporary hardness declined
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
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
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
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