1,721,056 research outputs found
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
Effects of the non-indigenous bivalve Ruditapes philippinarum on meiofaunal communities of the Tagus Estuary
No full textA meiofauna é, atualmente, considerada como um grupo de organismos com elevado
potencial para a monitorização de eventuais efeitos ecológicos resultantes de
perturbações naturais e/ou antropogénicas nos ecossistemas aquáticos. A presença do
bivalve não-indígena R. philippinarum no estuário do Tejo apresentou uma
oportunidade para avaliar o uso das comunidades da meiofauna, particularmente os
nematodes, como bioindicadores que permitam avaliar perturbações provocadas pela
presença de uma espécie alóctone.
O principal objetivo desta investigação foi verificar as respostas estruturais e funcionais
das comunidades de meiofauna perante a presença de um bivalve não-indígena. Este
objetivo foi atingido através da comparação de padrões de densidade, diversidade e
composição trófica das comunidades de meiofauna, especialmente os nematodes, em
locais com diferentes abundâncias de R. philippinarum. Todas as análises realizadas
mostraram que a densidade, os padrões de distribuição, diversidade e a composição
trófica das comunidades de nematodes foram estruturados principalmente por fatores
ambientais como o tipo de sedimento e a salinidade e não tanto pelas densidades de R.
philippinarum; Effects of the non-indigenous bivalve Ruditapes philippinarum
on meiofaunal communities of the Tagus estuary.
|ABSTRACT:
Meiofauna are presently regarded as very suitable organisms to monitor potential
ecological effects of natural and anthropogenic disturbances in aquatic ecosystems.
The presence of the non-indigenous bivalve R. philippinarum in the Tagus estuary
presented the opportunity to evaluate the ability of meiofauna communities,
specifically nematodes, as indicators to assess disturbances promoted by an
allochthonous species.
This research focused on the benthic meiofauna assemblages response to the presence
of a non-indigenous bivalve. Density, diversity and trophic composition patterns of the
meiofauna communities, particularly nematodes were examined along the estuary
gradient and related to environmental conditions and the occurrence of R.
philippinarum. All the performed analysis showed that nematodes density, distribution
patterns, diversity and trophic composition were mainly structured by distinct
environmental factors like sediment grain size and salinity rather than by R.
philippinarum densities
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
Análise de cenários de governança na gestão da apanha da amêijoa-japonesa (Ruditapes philippinarum) em Portugal
No full textTese de mestrado, Ecologia Marinha, Universidade de Lisboa, Faculdade de Ciências, 2020A amêijoa-japonesa (Ruditapes philippinarum, Adam & Reeve 1850) é uma espécie não-indígena que foi introduzida em Portugal na década de 80 para fins comerciais. Atualmente encontra-se presente em vários sistemas costeiros portugueses como a Ria de Aveiro, a Lagoa de Óbidos, o Estuário do Tejo e o Estuário do Sado. No Tejo observou-se recentemente um crescimento acentuado na distribuição e na abundância desta espécie, que resultou num aumento exponencial no número de apanhadores e no rendimento da atividade de exploração desta espécie. A apanha de amêijoa-japonesa está regulamentada apenas no estuário do Tejo, estando definidas as técnicas de apanha permitidas, o limite diário e o tamanho mínimo de captura. Verifica-se um incumprimento geral da legislação vigente, quer em relação à apanha, quer à comercialização, assim como das condicionantes decorrentes dos instrumentos de gestão territorial com incidência no estuário. O não cumprimento das normas sanitárias para a exploração e comércio de moluscos bivalves representa um risco para a saúde pública decorrente desta atividade. O objetivo deste trabalho é desenvolver um modelo de gestão para a exploração da amêijoa-japonesa que compatibilize o quadro legal e instrumentos de gestão territorial com o estado atual da atividade e que promova a sua prática sustentável. Nesse sentido, é analisado o quadro legal envolvendo a exploração de marisco e bivalves em Portugal, a regulamentação para apanha e comércio desta espécie, os instrumentos de gestão territorial em vigor nas áreas exploradas e estratégias de gestão aplicadas em França (modelo de gestão que visa conservação das espécies), Espanha (modelo de gestão que visa a conservação das espécies e modelo de co-gestão comunitária) e Itália (modelo de co-gestão por concessões), assim como cenários de gestão propostos para o Tejo (regime misto com áreas de concessão e áreas livres; regime livre; regime de zonamento de artes/técnicas de apanha). O modelo proposto neste trabalho para a gestão da apanha de amêijoa-japonesa no estuário do Tejo engloba o modelo de co-gestão por concessões e o regime misto com áreas de concessões e áreas livres, acrescentando medidas complementares de criação de infraestruturas e alterações ao quadro legal. Para os outros sistemas abordados neste trabalho onde a exploração desta espécie é menos intensa do que no Tejo, é proposto: a criação de regulamentação direcionada para a Ria de Aveiro e fiscalização da atividade; a implementação de um modelo de co-gestão com a participação ativa dos apanhadores na Lagoa de Óbidos; e a implementação de medidas de regulamentação de época de defeso e de quantidades máximas diárias para o estuário do Sado Estes modelos deverão incluir a cooperação das pessoas envolvidas na exploração e comércio de amêijoa-japonesa, a monitorização da evolução da população de bivalves, o envolvimento de “stakeholders” e a compatibilidade com as condicionantes legislativas e dos instrumentos de gestão territorial das áreas exploradas.The Manila clam (Ruditapes philippinarum, Adam & Reeve 1850) is a non-indigenous species that was introduced in Portugal in the 1980s for commercial purposes. Currently, it occurrs in several Portuguese coastal systems such as Ria de Aveiro, Óbidos coastal lagoon, Tagus estuary and Sado estuary. A strong increase in the distribution and abundance of this species has been registered recently in the Tagus estuary, which resulted in an exponential growth in the number of harvesters and the yield of the exploitation of this species. The Manila clam harvesting is only regulated in the Tagus estuary, namely the harvesting techniques, daily harvesting quantities and minimum catch size. There is a general failure to comply with current legislation, both in relation to harvesting and marketing, as well as constraints arising from spatial planning tools in force on the estuary. The failure to comply with sanitary standards for the exploitation and trade of bivalve molluscs presents a risk to public health resulting from this activity. The aim of this work is to develop a management model for the exploitation of the Manila clam that reconciles the legal framework and spatial management tools with the current state of activity and promotes its sustainable practice. To achieve this goal, the legal framework involving the exploitation of seafood and bivalves in Portugal, the regulation for harvesting and trade of this species, the spatial management tools in force in the exploited areas and management strategies applied in France (management model aimed at species conservation), Spain (management model aimed at species conservation and community co-management model) and Italy (concession co-management model), as well as management scenarios proposed for the Tagus estuary (mixed regime with concession areas and free areas; free regime; zonation by harvesting techniques regime), were analysed. The model proposed in this work for the management of the harvesting of manila clam in the Tagus estuary includes the model of co-management by concessions and the mixed regime with concession areas and free areas, adding complementary measures to create infrastructures and changes to the legal framework. For the other systems addressed in this work, where the exploitation of this species is less intense than in Tagus, it is proposed: the creation of regulations directed to the Ria de Aveiro and surveillance of the activity; the implementation of a co-management model with the active participation of harvesters in Óbidos Lagoon; and the implementation of closed season regulation measures and maximum daily quantities for the Sado estuary. These models should include cooperation of people involved in the exploitation and trade of the Manila clam, a monitoring program of the bivalve population, the involvement of stakeholders and comply with the legislative framework and constrains of the spatial planning tools in force at the areas explored
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
Tell Me How You Look Like And I’ll Tell You Where You Come From: Identification Of Bivalves Shells’ Origin
No full textTese de mestrado, Ecologia Marinha, 2022, Universidade de Lisboa, Faculdade de CiênciasCerastoderma edule (Linnaeus 1768) and Cerastoderma glaucum (Bruguière 1799) are two sibling
species of cockles that can occur in sympatry. They are ecologically and economically important, have
a wide geographical distribution and are harvested all over Europe. In Portugal, cockles are commonly
found along all coastal areas and were the bivalve species with the highest landings in the country
between 2010 and 2020. This importance emphasises the need for unravelling the origin of an individual
using traceability techniques, when the harvesting location is doubtful, identifying and verifying illegal
fishing activity or benefiting consumers through the detection of mislabelled seafood products.
Distinguishing cockles’ populations based on morphological characteristics is difficult due to their
morphological similarities, however, species and geographic identification studies often use
morphological characteristics as tools to acquire most of this bivalve’s information. Geometric
morphometrics is one of the most successful methods based on morphometry, providing a visual
representation of shape change and producing shape variables that can be analysed through statistics.
The aim of this work was to study the geographical variation of the shell shape of Cerastoderma spp.
common in Portuguese aquatic systems such as Ria de Aveiro, the Tagus and Sado estuaries, the
Albufeira and Óbidos lagoons, etc. The possibility of inferring the origin of an individual using shell
morphology and multiple landmark-based geometric morphometrics methodologies was explored
alongside the possibility of using such methods as traceability techniques.
This work supports the use of landmark-based geometric morphometrics methods, being easy, low
cost and effective in the study of shell shape variation. Using these methods allowed the discrimination
of cockle populations from different aquatic systems on the Portuguese coast. Such methodologies could
be extended to other bivalve populations and aquatic systems, becoming beneficial for the traceability
of other populations and a valuable asset in fisheries in general
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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