10 results on '"A. de Olazabal"'
Search Results
2. An Examination of the Spanish Translation of the 50-item International Personality Item Pool Big-five Inventory in a Spanish Speaking Peruvian Sample.
- Author
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Hughes, David J., de Olazabal, Daniel Pizarro, Kratsiotis, Ioannis K., Twumasi, Ricardo, and Booth, Tom
- Subjects
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STRUCTURAL equation modeling , *PERSONALITY studies , *TRANSLATIONS , *INVENTORIES , *PERSONALITY - Abstract
The International Personality Item Pool (IPIP) five-factor model inventories are widely used for personality research and have been translated into multiple languages. However, the extent of the psychometric assessment of translated scales is variable, often minimal. The lack of psychometric scrutiny is particularly problematic because translation is an inherently complex process. Here, we present a structural analysis of one Spanish translation of the 50-item IPIP five-factor inventory in a sample of Peruvian, non-university educated, working adults (n = 778). A global confirmatory factor analytic (CFA) model of the a priori five factors failed to fit. So too did single factor models for four of the five factors, the exception being Neuroticism. Fit was improved via use of an exploratory structural equation measurement model, but the resultant solution showed very poor theoretical coherence. So, we explored the data for systematic measurement artefacts and sought to model them to improve the psychometric properties of the scale. Specifically, the pattern of factor loadings suggested that the lack of coherence might be due to the effects of the valence of item wording (i.e., positively or negatively worded items). CFA models including five substantive factors and a series of method factors modelling shared covariance based on item wording, improved fit and coherence. This investigation suggests that unless method factors are explicitly modelled the tested Spanish translation may not be suitable for use in certain Spanish-speaking countries or samples composed of non-university educated participants. More broadly, the study has implications for many translated scales, especially when used without thorough psychometric evaluation. [ABSTRACT FROM AUTHOR]
- Published
- 2020
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3. First record of the egg-carrying calanoid copepod Pseudodiaptomus marinus in the Adriatic Sea.
- Author
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de Olazabal, Alessandra and Tirelli, Valentina
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CALANOIDA , *SEAS , *COPEPODA , *CRUSTACEA , *INTRODUCED species , *RECORDS - Abstract
The Asian egg-carrying copepod Pseudodiaptomus marinus (Crustacea: Copepoda: Calanoida) was recorded for the first time in two different areas of the North Adriatic Sea (Mediterranean Sea). Its introduction was probably due to human activity linked to vessel traffic or aquaculture. [ABSTRACT FROM AUTHOR]
- Published
- 2011
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4. Congruence of symmetric matrices.
- Author
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de Olazabal, J.M.
- Subjects
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SYMMETRIC matrices , *MATHEMATICAL models - Abstract
Presents an equation and its solution on congruence of symmetric matrices. Determination of the diagonalization by congruence of symmetric matrices over K; Characteristics of ring K; Proving of the propositions.
- Published
- 1995
5. An extension of Vandermonde's determinant.
- Author
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Martin, K. and de Olazabal, J.M.
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DETERMINANTS (Mathematics) - Abstract
Presents an extension of Vandermonde's determinant inspired by the Lagrange-Sylvester Interpolation. Computations and formulae.
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- 1994
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6. Monstrilloids (Crustacea: Copepoda) from the Mediterranean Sea (Northern Adriatic Sea), with a description of six new species.
- Author
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Suárez-Morales, Eduardo, Goruppi, Alenka, de Olazabal, Alessandra, and Tirelli, Valentina
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MONSTRILLOIDA , *CRUSTACEA , *MARINE zooplankton , *SPECIES diversity - Abstract
Monstrilloid copepods collected during zooplankton surveys carried out over several years (2009-2016) in the Gulf of Trieste, northern Adriatic Sea, were examined. A total of seven species were found, of which six are undescribed, five of Cymbasoma and one of Monstrilla. These new species are described, illustrated and compared herein with its known congeners. Two of them are related to the C. rigidum species complex. One of these species is described based on both the male and the female; sexes were linked by identical details of the cephalic structure and the antennulary armature. Two previous reports of females attributed to C. tumorifrons from the Mediterranean relate to specimens that in fact belong to a new species, C. mediterranea. The most abundant species was M. grandis, which had a remarkable aggregation around the Trieste harbour in 2015. Male and female specimens of this assumedly widespread species were examined and the observed intra-specific morphological variability is reported and compared with previous illustrated reports; this nominal species probably this nominal species, probably represents a species complex. The addition of the new species here described brings the number of nominal species in the Mediterranean-Black Sea region to 26. [ABSTRACT FROM AUTHOR]
- Published
- 2017
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- View/download PDF
7. Annual dynamics of the mesozooplankton communities in a highly variable ecosystem (North Adriatic Sea, Italy).
- Author
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Camatti, Elisa, Comaschi, Alessandra, de Olazabal, Alessandra, and Fonda Umani, Serena
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ZOOPLANKTON , *ANIMAL communities , *ANIMAL classification , *INVERTEBRATE communities , *MARINE invertebrate populations - Abstract
Mesozooplankton community composition at the species/taxa level was investigated from January to December 2001, at eight stations in the northern Adriatic Sea. Annual dynamics, taxonomic composition and spatial diversity in relation to different trophic conditions are discussed as related to previous studies and to different conditions, such as the presence of mucilage events. Zooplankton communities all over the northern sub-basin were dominated by the cladoceran Penilia avirostris in summer, and by the calanoids Paracalanus parvus, Acartia clausi and the poecilostomatoids Oncaea spp. during the rest of the year. Whereas coastal communities were more variable with time and location, we were able to identify a group of offshore stations with a similar species/taxa composition and annual dynamics. Comparing the present results with previous studies, we observed significant changes in community composition in the time scale of 20 years, mostly due to a general decrease of A. clausi as the dominant species, being replaced by P. parvus. Also, P. avirostris swarms appear to have extended their temporal occurrence, and were present for longer periods of time when compared to past records. These changes might be related to the observed general increase of the average sea water temperature in the northern Adriatic Sea. [ABSTRACT FROM AUTHOR]
- Published
- 2008
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8. Regional and seasonal characteristics of epipelagic mesozooplankton in the Mediterranean Sea based on an artificial neural network analysis.
- Author
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Mazzocchi, M.G., Siokou, I., Tirelli, V., Bandelj, V., Fernandez de Puelles, M.L., Ak Örek, Y., de Olazabal, A., Gubanova, A., Kress, N., Protopapa, M., Solidoro, C., Taglialatela, S., and Terbiyik Kurt, T.
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ZOOPLANKTON , *CLIMATE change , *ARTIFICIAL neural networks , *BIOMASS , *SPECIES diversity - Abstract
Abstract: The cruises conducted in the spring and autumn of 2008 in the frame of the European project SESAME represented the first coordinated surveys that allowed acquiring a quasi-synoptic picture of epipelagic mesozooplankton in most regions of the Mediterranean Sea. Seasonal differences were recorded in biomass, total abundance, and community composition and structure. In both seasons, it did not appear a clear west-east decreasing gradient in total standing stock, but rather regional discontinuities. However, west or east preferences were observed in the distribution of some zooplanktonic groups and copepod species. An artificial neural network analysis (SOM) identified, in both seasons, a clear mesozooplankton regionalization, which resembled the autotrophic regimes based on color remote sensing data. The correspondence between the distribution of zooplankton communities and the trophic regimes appeared more precise in spring, when the increased concentration of chlorophyll a makes the Mediterranean Sea a more heterogeneous environment, but it was still visible in the more uniform oligotrophic autumn conditions. Three distinct types of mesozooplankton communities seem to flourish in the investigated regions: the first type is the most widespread and thrives in the “non-blooming” areas, the second type occurs in the “intermittently-blooming” areas, and the third type is a characteristic of areas with recurrent and intense phytoplankton blooms. Overall, the well defined regionalization of mesozooplankton that appears from our results corroborates the view of the Mediterranean Sea as a mosaic environment, as previously emerged from the analyses of different biological compartments. [Copyright &y& Elsevier]
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- 2014
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9. Inter-annual variations of planktonic food webs in the northern Adriatic Sea
- Author
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Fonda Umani, Serena, Milani, Luisella, Borme, Diego, de Olazabal, Alessandra, Parlato, Stefania, Precali, Robert, Kraus, Romina, Lučić, Davor, Njire, Jakica, Totti, Cecilia, Romagnoli, Tiziana, Pompei, Marinella, and Cangini, Monica
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PLANKTON , *FOOD chains , *GRAZING , *RANGELANDS - Abstract
Abstract: The temporal dynamics of microphytoplankton, microzooplankton and mesozooplankton were monitored over 37 months in the Adriatic Sea in order to identify alterations in the plankton structures, which can lead to, or enhance the production of macro-aggregates, that affected the entire northern basin in summers 2000 and 2002, and to assess any negative effects of mucilage on plankton temporal patterns. Samples were collected monthly, from June 1999 to July 2002, on three transects at 9 stations across the northern and central Adriatic Sea. Besides the high year-to-year variations in abundances and taxonomical composition, plankton communities only showed a clear seasonal succession during 2001, when since April a grazing food web developed and was able to control large sized phytoplankton increase. In spring–summer 2000 and 2002 consumer abundances remained quite low and the dominant mesozooplankton summer species (Penilia avirostris) did not reach its usual summer maximum. The lack of an efficient top control was more evident on the northernmost transect, where generally grazing food web prevails over the microbial one. A large part of the microphytoplankton blooms, although not particularly intense, was exported to the bottom in the particulate phase, where it was processed by bacteria, enhancing the production of refractory dissolved material. [Copyright &y& Elsevier]
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- 2005
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10. Multi-marker metabarcoding approach to study mesozooplankton at basin scale.
- Author
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Stefanni, Sergio, Stanković, David, Borme, Diego, de Olazabal, Alessandra, Juretić, Tea, Pallavicini, Alberto, and Tirelli, Valentina
- Abstract
Zooplankton plays a pivotal role in marine ecosystems and the characterisation of its biodiversity still represents a challenge for marine ecologists. In this study, mesozooplankton composition from 46 samples collected in summer along the western Adriatic Sea, was retrieved by DNA metabarcoding analysis. For the first time, the highly variable fragments of the mtDNA COI and the V9 region of 18S rRNA genes were used in a combined matrix to compile an inventory of mesozooplankton at basin scale. The number of sequences retrieved after quality filtering were 824,148 and 223,273 for COI and 18S (V9), respectively. The taxonomical assignment against reference sequences, using 95% (for COI) and 97% (for 18S) similarity thresholds, recovered 234 taxa. NMDS plots and cluster analysis divided coastal from offshore samples and the most representative species of these clusters were distributed according to the dominant surface current pattern of the Adriatic for the summer period. For selected sampling sites, mesozooplankton species were also identified under a stereo microscope providing insights on the strength and weakness of the two approaches. In addition, DNA metabarcoding was shown to be helpful for the monitoring of non-indigenous marine metazoans and spawning areas of commercial fish species. We defined pros and cons of applying this approach at basin scale and the benefits of combining the datasets from two genetic markers. [ABSTRACT FROM AUTHOR]
- Published
- 2018
- Full Text
- View/download PDF
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