1,720,962 research outputs found
Occurrence of Microplastics in Coastal Sediments From the Inner Oslofjord, Norway
No full textGlobally, microplastics (MPs) are expected to
accumulate at high concentrations in coastal
sediments because these are readily linked with
both land- and sea-based inputs, and changes in
density and buoyancy facilitate sinking to the
seabed. The Fjordic systems on the Norwegian
coast have received some attention, reporting
the presence of MPs in sediment samples,
although explanations for the reported values
are mostly lacking. This study presents records
of MPs (< 1 mm) in coastal sediments sampled
in the Vestfjord, the western part of the Inner
Oslofjord, from 100 m of water depth. Our aim
was to understand the scale of which the release
of MPs in the Vestfjord was influenced by a
WWTP system (VEAS) and how the redistribution
of MPs is driven by oceanographic
currents acting in the fjord. Thus, the upper 0—
5 cm of sediment cores were analysed from
three areas of interest: two stations (ST4, ST5)
in proximity of the VEAS diffuser and one
(ST2) from the Vestfjord’s inlet. MPs were
extracted from sediments using a NaI solution
and were validated with μFT-IR. The
distribution of MPs’ shape (fibre, fragment,film) and polymers in sediments was compared
with grain-sizes (clay, silt, sand) via Canonical
Correspondence Analysis (CCA).The most
polluted area was ST4 with a total of 1.042
MPs/g dw, followed by ST5 with 0.524 MPs/g
dw, both of which are close to the WWTP
outlet. ST2 had the lowest concentration, 0.084
MPs/g dw. Fibres were the most common
morphology found (76%), whilst fragments and
films occurred with lower concentrations (18%,
6%). Common polymers were PES (50%), PP
(18%), PMMA (9%), elastane (4%) and
cellulosic materials (4%). MPs appear to
preferentially accumulate according to their
morphology and polymeric origin. Such that
clays had preferential accumulation of PMMA,
PA, PC, elastane and cellulosic materials; in silt
PES, LD-PE, PS, PVC and films; in sand PP,
fibres and fragments. The analyses on the
vertical distribution of MPs showed that the
occurrence of plastic particles decreased from
2002 and 2015 for ST2 and ST5 whilst
increased for ST4. The input of plastic debris at
ST4 and ST5 appears to derive from the release
of treated waters from the WWTP diffuser with
ST4 as the main accumulation zone - located
down current from the diffuser. Due to the
position of ST2 it is uncertain if the main input
of MPs hails from the Inner or the Outer
Oslofjord. Further analyses are needed to
understand the main inputs of plastic debris in
this area
Accumulation and distribution of microplastics in coastal sediments from the inner Oslofjord, Norway
No full textMicroplastic presence in benthic marine systems is a widely discussed topic. The influence of the natural matrix on microplastic distribution within the sedimentary matrix is often overlooked. Marine sediments from the western inner Oslofjord, Norway, were investigated for temporal trends, with a particular focus on the relationship between sediment grain-sizes and microplastic distribution. Density separation, optical microscopy and chemical validation were used to categorize microplastics. Microplastic concentrations ranged from 0.02 to 1.71 MPs g −1 dry weight (dw). Fibres were the most common (76%), followed by fragments and films (18%, 6%). Common polymers were polyesters (50%), polypropylene (18%), polymethylmethacrylate (9%), rayon and viscose (5%) and elastane (4%). Microplastics appear to accumulate preferentially according to their morphology and polymer type in certain sediment grain-sizes. Microplastics inputs to the Oslofjord appear to derive from a wastewater treatment plant in the vicinity. Although, the redistribution of microplastics within the fjord needs further investigation
Risposta del plancton calcareo alle variazioni di CO2 in aree di interesse del Mar Mediterraneo e del Mare Artico durante gli ultimi 30.000 anni: stato dell’arte del progetto di dottorato
No full textL’intervallo di tempo compreso tra gli ultimi 30.000 anni ad oggi è caratterizzato da alcuni dei più
importanti eventi climatici recenti, a partire dall’Ultimo Massimo Glaciale (Mix et al., 2001) fino alle variazioni
climatiche forzate da fattori antropici. Lo studio delle associazioni di Coccolitoforidi può aiutarci a ricostruire
le condizioni paleoambientali e paleoceanografiche, in quanto questi organismi marini fitoplanctonici sono
influenzati direttamente dalle variazioni dei fattori ambientali che caratterizzano la colonna d’acqua (i.e.,
temperatura, salinità, nutrienti, ecc.). Al termine del loro ciclo vitale, questi organismi a guscio calcareo si
accumulano in grandi quantità nei sedimenti marini e si conservano nel record sedimentario sotto forma di
nannofossili calcarei (Baumann et al., 2005).
L’attività svolta per il progetto di dottorato, ha come obiettivo principale lo studio dell’impatto delle
variazioni di CO2 sulle comunità di Coccolitoforidi durante gli ultimi 30.000 anni in aree di indagine strategiche.
In particolare, sono in fase di analisi tre carote di sedimento campionate nel bacino del Mediterraneo: NDT_09
campionata nel Mar Tirreno meridionale, ND14Mbis nel mar Ionio settentrionale e NDT_22 campionata nel
Mar Ligure (crociera NextData 2016; Lirer et al., 2017). Inoltre, saranno analizzati due record marini del
Mare Artico raccolti in prossimità del Bellsund Drift, nel margine occidentale dell’arcipelago delle Svalbard
durante le campagne oceanografiche IRIDYA (OGS, Crociera Artica 2021) per la carota IRIDYA_02 (Lucchi
et al., 2014) ed EUROFLEETS-2 (crociera PREPARED, 2014; Lucchi et al., 2014) per il box core GS191-
04BC. L’attività di laboratorio svolta per l’analisi delle associazioni di nannofossili calcarei comprende la
campionatura delle carote, la preparazione dei campioni attraverso i metodi di filtrazione e smear slides e
l’analisi quantitativa dei nannofossili calcarei al microscopio ottico. I dati micropaleontologici vengono
correlati ai risultati delle analisi geochimiche ottenuti attraverso metodi di X-Ray Fluorescence-core scan e
delle misure paleomagnetiche.
L’attività di ricerca è inclusa nei progetti: AMUSED (INGV – PI: Patrizia Macrì); IRIDYA - PRA 2021-
0012 (OGS – PI: Renata Giulia Lucchi), TIMED - ECR-COG (PI: Isabel Cacho) e nel progetto INGV 2019
(Paleoclimate variability during Late Holocene in the Central Mediterranean and Balkans: terrestrial and
marine archive comparison - PI: Ilaria Isola). Con questo contributo scientifico si vogliono illustrare i risultati
preliminari conseguiti durante il primo anno di dottorato e le attività che verranno svolte per la sua conclusione
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
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
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
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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