1,720,988 research outputs found
EFFECT OF WIDESPREAD ENVIRONMENTAL DISTURBANCES ON MEIOFAUNA AND FREE-LIVING NEMATODES
Get PDFNatural and human disturbances may affect ecosystems compromising their functioning. It is, therefore, important to define prevention strategies to avoid irreparable damages, where the first action implicates the identification of possible environmental criticalities followed by the management actions.
For this purpose, it is necessary to identify reliable and easily applicable bioindicators that can give
an early response to potential environmental disturbance and define the ecological quality of marine coastal systems. Meiofauna (animals from 500 μm to 45 μm in size), and in particular free-living
nematodes, appear good candidates in the framework of the ecological assessment because they
have all the above cited characteristics along with a wide distribution in all the types of environments
and substrata. Thus, the present Ph. D. project takes into consideration six study cases set in a wide
geographical span and under environmental disturbances frequently occurring in the coastal systems. The primary project aims are i) to demonstrate that meiofauna and nematodes can be
efficiently used for the assessment of the health status in marine habitats; ii) to increase the number
of meiobenthic indicator taxa that can be regarded as “sentinels” of human disturbance; iii) to further calibrate the tools so far available for the classification of Ecological Quality (EcoQ) to encourage the use of meiofauna in the assessment of the status of underwater life.
The first study case was carried out in the Maldivian Archipelago (Indian Ocean), where human activities such as dredging and infilling are common practices, which led to a decrease in the taxonomic diversity of many animal species. In this context, the study of nematode communities shows that their taxonomical composition and functional traits (i.e. trophic and life strategy) are mainly influenced by the reef exposure and topography (i.e., lagoon and ocean reefs) and the depth gradient. The high abundance of k-strategists in ocean reefs might indicate a higher EcoQ when compared to lagoon reefs; however, the absence of significant differences in life strategy functional
diversity and functional redundancy indicates that a recovery process is underway. The results
obtained suggest that nematodes could add important information to the vulnerability and resilience
of the benthos and, therefore, should be included in the biomonitoring activities of the Coral
Degradation Zones (CDZs) along with the reef bioconstructors.
The second case study from the Indian Ocean (Indonesia), was carried out in two seagrass
meadows characterized by different sedimentological regimes and anthropogenic pressure. The
lowest meiobenthic abundance and diversity found at the Barat meadow along with the major
sediment modifications suggested a higher anthropogenic pressure in this site. Rare meiobenthic
taxa (<1% of the total abundance in all investigated samples) revealed significant differences in the composition of the meiobenthic assemblage suggesting the key role of rare meiobenthic taxa as possible indicators of spatial variability generated by engineer species and different environmental conditions.
The third study concerned the Southern Ocean at Terra Nova Bay (Antarctica), where the effects of the human activities in the Mario Zucchelli Research Station were compared with the natural
disturbance occurring in the penguin colony located at Adelie Cove. Here, the high contribution of r-
strategists corroborates the hypothesis that the chronic impact of the penguin colonies may have
stronger effects on the meiobenthos than the human activities at the research station and, as
reported in the Indonesian study, the assemblage structure of rare meiobenthic taxa is confirmed to
be more susceptible to environmental variations, rather than the whole assemblage structure.
In the fourth study, a commercial port of the Ligurian Sea, nematode communities were investigated in stations at an increasing distance from the port. The stations selected at an increasing distance from the port outlet aim to detect how ports may influence the benthic nematodes from surrounding coastal areas. The taxonomical and functional distribution of the nematode species appeared influenced by the contamination level, granulometry, and organic load of sediments. According to
these results, the nearest stations to the port outlet appeared to be the most polluted, while the coast close to Bergeggi Marine Protected Area seemed as the most pristine area. Furthermore, the study
indicated a selection of the genera that may be considered as sentinels of sediment contamination
and organic enrichment. The maturity index suggested that the different proportion of the nematode life-strategies is an effective tool to assess the EcoQ of sediments.
In the fifth study the sediments within three commercial ports from the Adriatic Sea (Ancona and Trieste, Italy; Koper, Slovenia) were investigated, the nematode analysis indicated that r-strategist
genera were dominant in all three study areas. Despite the high contamination levels, Trieste showed high nematode biodiversity which suggests a potential adaptation of nematodes to a long-standing contamination. A co-occurrence analysis was performed to further implement the sets of bioindicator
genera concerning their different opportunistic behaviors and to identify which genera cohesively respond to site-specific environmental conditions. The results encourage the use of nematodes for
the EcoQ assessment of port seabeds.
Despite the good response of meiofauna and nematodes as bioindicators of anthropogenic
disturbance, the taxonomic identification of these organisms remains a time-consuming activity and requires the supervision of experienced taxonomists. To overcome this problem, in the sixth study,
was proposed a combination of morpho-functional traits (i.e. amphids, cuticles, buccal cavities, and tail shapes) as an alternative to the taxonomic identification of the nematode specimens. The
approach was tested by employing a meta-analysis of a data set of study cases from the
Mediterranean Sea. The statistical results revealed that the trait combination perfectly mirrors the
changes in the taxonomic community structure at the genus level which makes it possible to suggest
this approach as a rapid test of nematode fauna changes for biomonitoring purposes
Quality of institutions and employment dynamics of social enterprises: Evidence from Italian regions
Get PDFThis paper empirically investigates the effect of the quality of regional institutions on social enterprises’ employment growth. Using an original panel dataset of social enterprises during 2011–2020, FE and GMM estimates provide three findings. First, higher institutional quality at the regional level positively affects firms’ employment. Second, the effect is heterogenous and varies across firms’ size. Third, corruption in the provision of public services significantly inhibits the “speed” of employment growth for Micro and SMEs
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
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
Essential Oils as Nematicides in Plant Protection—A Review
Get PDFBy 2030, the European Commission intends to halve chemical pesticide use and its consequent risks. Among pesticides, nematicides are chemical agents used to control parasitic roundworms in agriculture. In recent decades, researchers have been looking for more sustainable alternatives with the same effectiveness but a limited impact on the environment and ecosystems. Essential oils (EOs) are similar bioactive compounds and potential substitutes. Different studies on the use of EOs as nematicides are available in the Scopus database in the scientific literature. These works show a wider exploration of EO effects in vitro than in vivo on different nematode populations. Nevertheless, a review of which EOs have been used on different target nematodes, and how, is still not available. The aim of this paper is to explore the extent of EO testing on nematodes and which of them have nematicidal effects (e.g., mortality, effects on motility, inhibition of egg production). Particularly, the review aims to identify which EOs have been used the most, on which nematodes, and which formulations have been applied. This study provides an overview of the available reports and data to date, downloaded from Scopus, through (a) network maps created by VOSviewer software (version 1.6.8, Nees Jan van Eck and Ludo Waltman, Leiden, The Netherlands) and (b) a systematic analysis of all scientific papers. VOSviewer created maps with keywords derived from co-occurrence analysis to understand the main keywords used and the countries and journals which have published most on the topic, while the systematic analysis investigated all the documents downloaded. The main goal is to offer a comprehensive understanding of the potential use of EOs in agriculture as well as which directions future research should move toward
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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