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Fitoplâncton como alimento para microcrustáceos e rotíferos nos períodos de seca e enchente no lago Tupé, Manaus-AM
Get PDFThe lake Tupé, which is located near Manaus, in the Amazonas state, is a black-water
lake of great richness of phytoplanktonic and zooplanktonic species. The zooplanktonic
organisms may belong to different size categories: microplankton, mesoplankton, and
macroplankton; but the phytoplanktonic organisms may belong to picoplankton,
nanoplankton, and microplankton. Because of the size difference, the zooplanktonic
organisms might be feeding on phytoplanktonic organisms of different sizes. The goal of
this research was to evaluate the importance of phytoplankton different fractions as food
for microcrustaceans and planktonic rotifers in the low waters period (2015) and rising
waters (2016) at the lake Tupé, Manaus-AM. The samples were conducted in two months
at the low Waters period and two months in the rising Waters period at the lake Tupé
(Reserve of Sustainable Development of Tupé). As sampling criteria, the estimated photic
zone extension was used with the assistance of transparency measures by the Secchi disc.
A PVC tube of 50 mm in diameter and 3 m in length with a water retention valve which
was inserted in this extension and its content was placed in a bucket, homogenized and 2
L samples were taken. At the laboratory, the samples were fractionated in order to obtain
the picoplankton, nanoplankton, and microplankton and later the biomass of each fraction
was measured through the Chlorophyl-a. An experiment was placed at lake Tupé during
24 hours in the low Waters period and rising water period. The zooplanktonic and
phytoplanktonic samples were collected with a PVC tube of 4 m in length, later they were
taken to the laboratory to be analyzed. The zooplanktonic organisms. The zooplanktonic
organisms were counted and measured. The phytoplankton samples were fractionated in
order to obtain the differences in size fraction, and later, the biomass of each fraction was
measured. The total low Waters period biomass was 27,03 μg/L, and the total rising
Waters biomass was 36,59 μg ̸ L. There were no statistically significant differences
between the biomass of the picoplankton, nanoplankton and microplankton in the two
periods. The zooplanktonic organisms did not exercised selective predation pressure on
just one of the phytoplankton size fractions. Instead, they exercised predation pressure on
phytoplankton three size fractions.O lago Tupé, localizado próximo a Manaus no Amazonas, é um lago de água preta de
elevada riqueza de espécies fitoplanctônicas e zooplanctônicas. Os organismos do
zooplâncton podem pertencer a diferentes categorias de tamanhos: microplâncton,
mesoplâncton e macroplâncton; já os organismos fitoplanctônicos podem pertencer ao
picoplâncton, nanoplâncton e microplâncton. Por terem tamanhos diferentes os
organismos zooplanctônicos podem estar se alimentando de tamanhos diferentes de
organismos fitoplanctônicos. O objetivo dessa pesquisa foi avaliar a importância de
diferentes frações do fitoplâncton como alimento para microcrustáceos e rotíferos
planctônicos nos períodos de seca (2015) e enchente (2016) no lago Tupé, Manaus-AM.
As coletas foram realizadas em dois meses da seca e dois meses da enchente no lago Tupé
(RDS do tupé). Como critério de amostragem utilizou-se a extensão da zona eufótica
estimada com auxílio de medidas de transparência por disco de Secchi. Um tubo de PVC
de 50 mm de diâmetro e 3 m de comprimento com uma válvula para retenção da água foi
inserido nessa extensão e seu conteúdo foi colocado em um balde, homogeneizada e
amostras de 2 L foram retiradas. Em laboratório, as amostras foram fracionadas para se
obter o pico, nano e microfitoplâncton e depois a biomassa de cada fração foi medida
através da clorofila-a. Um experimento foi colocado durante 24 horas no período de seca
e enchente no lago Tupé. Amostras de zooplâncton e fitoplâncton foram coletadas com
um tubo de PVC de 4 m de comprimento, depois foram levadas ao laboratório para serem
analisadas. Os organismos zooplanctônicos foram contados e medidos. A amostra de
fitoplâncton foi fracionada para se ter as diferentes frações de tamanho e, depois foi
medida a biomassa de cada fração. A biomassa total da seca foi de 27,03 μg/L e a
biomassa total da enchente foi de 36,59 μg ̸ L. Não houve diferença estatisticamente
significativa entre a biomassa do pico nano e microfitoplâncton nos dois períodos. Na
seca e na enchente houve diferença estatisticamente significativa entre microplâncton e
mesoplâncton da amostra inicial e também da amostra final do experimento. A maior
densidade dos organismos foi encontrada no experimento do período de seca. Os
organismos zooplanctônicos não exerceram pressão de predação seletiva sobre apenas
uma das frações de tamanho do fitoplâncton, exerceram pressão de predação sobre as três
frações de tamanho do fitoplâncton. Estudos que levem em conta a pressão de predação
sofrida pelos organismos zooplanctônicos e destes sobre organismos fitoplanctônicos são
necessários para entender se os controles na cadeia trófica são top down ou bottom up
Cultivo de Cladóceros (Crustacea: Branchiopoda: Cladocera) Adultos, em Laboratório Provenientes do Lago Tupé, Manaus – AM
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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
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
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