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Zooplankton as an indicator of the trophic status in shallow lakes
No full textZooplanktonski organizmi zauzimaju središnji položaj u hranidbenim mrežama plitkih jezera te su poznati indikatori ekoloških promjena temeljem njihovih strukturalnih (raznolikost, brojnost, biomasa) i funkcionalnih (način prehrane) obilježja. Plitka jezera umjereno kontinentalne i mediteranske klime razlikuju se s obzirom na utjecaj čimbenika okoliša, što uzrokuje razlike u interakcijama abiotičkih i biotičkih čimbenika. Cilj je ovog rada bio utvrditi: (i) raznolikost, brojnost i trofičku strukturu zooplanktona; (ii) indekse zooplanktona i usporediti ih s indeksima stupnja trofije; (iii) prijedlog mjera upravljanja i očuvanja plitkih vodenih tijela u dvije različite klimatske zone (umjereno kontinentalnoj i mediteranskoj) Hrvatske. U devet lokvi determinirano je 48 vrsta zooplanktona, a kolnjaci su dominirali s 36 vrsta. Kompleksnost habitusa, pokrovnost makrofita i koncentracija hranjivih tvari pokazali su se kao značajni čimbenici u strukturiranju zooplanktona plitkih vodenih tijela obaju geoklimatskih područja. Zooplankton u plitkim vodenim tijelima umjereno kontinentalne klime obilježavaju populacije veće raznolikosti, a u mediteranskoj klimi zooplankton su obilježile populacije veće brojnosti, posebno vrsta rodova Lecane i Brachionus. Rezultati rada potvrđuju važnost zooplanktona kao dobrog indikatora u procjeni trofičkog i ekološkog stanja plitkih vodenih tijela te pružaju osnovu u određivanju smjernica očuvanja i upravljanja tim osjetljivim i ugroženim ekosustavima.Zooplankton organisms occupy a central role in the food webs of shallow water bodies, and are known indicators of ecological changes based on their structural (diversity, abundance, biomass) and functional (feeding) traits. Shallow lakes of temperate-continental and Mediterranean climates differ related to the effects of environmental factors, which cause differences in the interactions of abiotic and biotic factors. The aim of this study was to determine: (i) the diversity, abundance and trophic structure of zooplankton; (ii) zooplankton indices in comparison to the trophy state indices; (iii) a proposal for measures in the management and conservation of shallow water bodies in two different climates of Croatia. In nine ponds, 48 species of zooplankton were determined, and rotifers dominated with 36 species. Habitat complexity, macrophyte coverage, and nutrient concentrations were indicated as significant factors in the structuring of zooplankton in shallow water bodies of both geoclimate regions. Zooplankton in the temperate-continental climate was characterized by populations of higher diversity, while in the Mediterranean climate zooplankton was characterized by populations of higher abundance, particularly species of genera Lecane and Brachionus. Results of this study support the importance of zooplankton as a sentinel indicator in assessing the trophic and ecological status of shallow water bodies and provide a basis for determining guidelines in the conservation and management of these sensitive and endangered ecosystems
The neurotoxic effects of domoic acid
No full textDomoična kiselina je neurotoksin, glavni predstavnik ASP toksina (engl. Amnesic Shellfish Poisoing; amnezijsko trovanje školjkašima). Može se bioakumulirati u morskim organizmima kao što su školjkaši i ribe koji se hrane fitoplanktonom, glavnim izvorom toksičnih spojeva u moru. Simptomi trovanja školjkašima, koji u sebi sadrže domoičnu kiselinu, kod čovjeka su gubitak pamćenja, dezorijentiranost, glavobolja, abdominalni grčevi, povraćanje te koma. Nažalost, smrt je također mogući ishod trovanja i to samo nekoliko dana nakon konzumacije intoksiciranih školjkaša. Toksični fitoplanktonski organizmi svojim masovnim razmnožavanjem povećano troše kisik i na taj način uzrokuju cvjetanje algi, često nazvano i cvjetanje mora, koje može biti uzrok masovnom trovanju mekušaca, riba, ptica i ostalih organizama koji su na bilo koji način povezani uz more.Domoic acid is a neurotoxin, the main representative of the ASP group of toxic compounds (Amnesic Shellfish Poisoning). It can be bioaccumulated in marine organisms such as bivalves and fishes, which feed on phytoplankton, the main source of toxic compounds in the sea. Symptoms of poisoning with shellfish that contain domoic acid in humans include memory loss, disorientation, headache, abdominal cramps, vomiting and finally coma. Unfortunately, death is also a possible outcome of poisoning, just a few days following ingestion of intoxicated shellfish. Toxic phytoplankton organisms, with a high mass reproduction efficiency, increasingly consume oxygen and cause algae blooms, which may cause mass poisoning of molluscs, fishes, birds and other organisms, which are in any way associated with the sea
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
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
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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