1,720,965 research outputs found
Foxes provide a direct dispersal service to Phoenician junipers in Mediterranean coastal environments: ecological and evolutionary implications
No full textBackground and aims – Exploring the role of mammalian carnivores as seed dispersers in Mediterranean environments is crucial for understanding biotic interactions and preserving mutualistic networks in areas with high biodiversity. We examine the potential role of the Sardinian fox ( Vulpes vulpes subsp. ichnusae ) as a seed-disperser of two juniper species ( Juniperus phoenicea subsp. turbinata and J. oxycedrus subsp. macrocarpa ) in Mediterranean coastal environments.Methods – Observational and manipulative experiments were conducted in five coastal sites in north-western Sardinia (Italy) between 2010 and 2013.Key results – We found that Sardinian fox actively disperses seeds of J. phoenicea subsp. turbinata, whereas no evidence was obtained for the fox dispersing seeds of J. oxycedrus subsp. macrocarpa. Fox scat contained, on average, 73–86 J. phoenicea subsp. turbinata seeds, accounting 16.3–17.8 % of the average dung weight. The role of Sardinian fox as a primary disperser of J. phoenicea subsp. turbinata is by directly dispersing juniper seeds (via defecation) to a specific microhabitat (i.e. 80–90 % of dung was released on dwarf plants, mainly Helichrysum italicum subsp. microphyllum ), which positively affected the survival of emerged seedlings). We quantified that fox dispersed 30 to 100 seeds per day per hectare (3 500–10 500 seeds per hectare in one winter season).Conclusions – We reported that Sardinian fox is a direct disperser of J. phoenicea subsp. turbinata, thus playing a major role in secondary successional dynamics in Mediterranean coastal environments. Evolutionary implications are discussed, in that the positive interaction between Sardinian fox and J. phoenicea subsp. turbinata could be recent, following the introduction of fox to the Tyrrhenian islands during the 7 th –6 th millennium BC
Gradients of salinity and plant community richness and diversity in two different Mediterranean coastal ecosystems in NW Sardinia
No full textThis study aimed to test if differences in soil salinity, plant richness and diversity were significantly affected by habitat, site and distance from the seashore at three sandy and three rocky coastal sites in north-western Sardinia.Each site has been divided into three belts placed at an equal distance of 50 m from the shoreline. We measured soil salinity using a probe and vascular plants richness and diversity using linear transects at all sites. Average soil salinity varied from 0.115 g/l to 0.180 g/l; it was higher in the rocky habitats than in the sandy ones. A total of 21 species were found per transect/site at the rocky sites and 30 species per transect/site at the sandy sites, with an average of Shannon and Weaver's Diversity Index of 1.8 per each belt at each site. These data confirm that, also in the Mediterranean islands, there are coastal gradients of soil salinity from the seashore to inland areas and that also vascular plant richness and diversity are influenced by the distance from the sea. Soil salinity was strongly affected by the type of habitat, being average at the rocky coasts and negligible at the sandy shores. The site effect was not significant for both soil salinity and plant richness and diversity
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe 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
Upcycling of plastics recovered from enhanced landfill mining through pyrolysis.
No full textSince 1950 the global plastics production increased at a compound annual
growth rate (CAGR) of about 8.5 % and it is expected to grow in the next 5 years
at a CAGR of about 4 %. The estimated amount of plastics that ended up in
landfill and natural environment in the past 70 years is 4.9 billion tonnes. Most of
this comprises of thermoplastics which can be potentially recycled and
reintroduced in the new circular plastic economy reducing the use of virgin fossil
resources. To achieve this, more information is needed on recovered plastics
physico-chemical characteristics and their suitability for conventional recycling
processes. Due to the expected contamination and degradation of excavated
plastics, potential upcycling routes need to be explored to produce marketable
products. The plastic recycling, fresh waste or excavated, needs to fit into the
circular economy strategy which aims to maximise service life and minimise
waste. In the case of recovered plastics, the starting material is unused and must
be renovated to become useful again. Between common recycling routes for
fresh plastic waste, chemical recycling was found in line with the circular economy
concept. Specifically, the pyrolysis method leads to the production of chemical
compounds that can be used in the plastic industry. This PhD investigates the
feasibility of producing valuable products from the pyrolysis of excavated plastics
from municipal solid waste (MSW) landfill. Firstly, the physico-chemical
characteristics of genuine plastic from landfills were analysed. The chemical and
mechanical properties of buried plastics were hypothesised to be affected by the
chemical, biochemical and physical parameters within a landfill environment.
Secondly, the potential valuable products from the pyrolysis of recovered plastics
were investigated. Polyethylene and polypropylene represented 64 wt% of total
recovered plastics. The samples with storage of more than 10 years in landfill
showed a general greater extent of degradation compared to newer samples. The
pyrolysis of excavated plastics at 500°C and 650°C produced the highest level of
hydrocarbons and most of the pyrolysis products fitted within the naphtha range
(C6-C10) which has a high potential to be used in the petrochemical cluster. The
findings from this PhD bring to the attention that buried plastics have hidden
potential. These plastics have, in the past, been considered useless by virtue of
being landfilled and are potentially harmful to the environment and ecosystem
long-term in closed landfill sites. This work demonstrates the potential of
recovering value from excavated plastics as part of an enhanced landfill mining
project, reducing the need for virgin fossil fuel, preventing long-term pollutants
release and producing valuable and useful products.PhD in Energy and Powe
Variations on the Author
Get PDF“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
Get PDFWe 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
Get PDFWe 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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