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| Registros recuperados: 35 | |
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| Vigneau, Joel; Mahevas, Stephanie. |
| Measuring fish on a market or on board a vessel is the most common action taken by biologists all around the world to gather data for stock assessment. The samples coming from this kind of survey are of vector type and are not straightforward to analyse and compare. This paper proposes a generic tool that enables to investigate in any multinomial like sampling scheme. The use of this tool will be discussed based on examples from two different sampling designs. One is a sampling of commercial market categories and the other is a métier based sampling. The research of outliers, misallocated samples or potential bias, the stratification and the analysis of within and between strata variance will be discussed with the objective of constructing the best... |
| Tipo: Text |
Palavras-chave: Stratification; Sampling design; Length structure; Market sampling. |
| Ano: 2005 |
URL: http://archimer.ifremer.fr/doc/2005/acte-2698.pdf |
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| Perrot, Laurie; Gohin, Francis; Ruiz-pino, Diana; Lampert, Luis; Huret, Martin; Dessier, Aurelie; Malestroit, Pascale; Dupuy, Christine; Bourriau, Paul. |
| Coccolithophore blooms occur regularly from April to June in the Bay of Biscay where they have been observed for many years from ocean-colour imagery thanks to the ability of their calcite plates to scatter light. They are easily depicted on interpolated images of non-algal Suspended Particulate Matter (SPM) derived from satellite reflectance data in May, at the time of the PELGAS (PELagique GAScogne) annual surveys. Over the springs 2012 to 2015, the PELGAS surveys provided in-situ data on the turbidity throughout the water column and on the hydrological environment prevailing during the blooms in the vicinity of the continental shelf break. The satellite-derived SPM in the area of coccolithophore blooms was closely related to measured turbidity in the... |
| Tipo: Text |
Palavras-chave: Bay of Biscay; Ocean colour; Suspended particulate matter; Turbidity; Coccoliths; Stratification. |
| Ano: 2018 |
URL: https://archimer.ifremer.fr/doc/00416/52790/53689.pdf |
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| Marques,Pedro Rocha; Barcellos,Júlio Otávio Jardim; Dill,Matheus Dhein; Dias,Eduardo Antunes; Azevedo,Eduardo Vaz Torres; Lampert,Vinícius do Nascimento; McManus,Concepta Margaret. |
| The aim of this experiment was to identify improvement demands for farms with different levels of competitiveness in the west of Rio Grande do Sul state, Brazil. A total of 63 owners of large farms were interviewed (farms with an area greater than 900ha) by applying a semi-structured questionnaire, guided by four drivers: technology (TEC), management (MAN), market relations (MR) and the institutional environment (IE).It was used the Statistical Analysis System 9.2 software to perform the cluster analysis and identify farmers' characteristics. Three random clusters with different levels of competitiveness were observed: low competitiveness level (LCL), middle competitiveness level (MCL) and high competitiveness level (HCL). The 29 variables (sub factors)... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Cluster; Level of impact; Management; Ranking; Stratification. |
| Ano: 2015 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-84782015000300480 |
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| Vigneau, Joel; Mahevas, Stephanie. |
| Measuring fish on board fishing vessels or at fish markets to collect data for stock assessment purposes is one of the most straightforward actions carried out by fisheries scientists worldwide. However, such samples are not straightforward to handle and analyse because of their vector-type structure. A generic tool that allows investigation in any multinomial-like sampling scheme is provided, as long as the scheme is built on a ratio estimator, which is the case for most length sampling in the fisheries sector. The use of this tool is discussed using data obtained from two different sampling designs, one consisting of commercial market samples by category and the other on fishing activity or metier. The identification of outliers, misallocated samples, or... |
| Tipo: Text |
Palavras-chave: Stratification; Sampling design; Market sampling; Length structure. |
| Ano: 2007 |
URL: http://archimer.ifremer.fr/doc/2007/publication-2731.pdf |
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| Poletto,Tales; Muniz,Marlove Fátima Brião; Poletto,Igor; Stefenon,Valdir Marcos; Maciel,Caciara Gonzatto; Rabusque,Jéssica Emilia. |
| ABSTRACT: This study evaluated the efficiency of methods to overcome seed dormancy in different storage periods in the production of pecan seedlings. Seeds were submitted to the following treatments: T1, T4 and T7 - control treatments (seeds with no treatment, stored at room temperature for 30, 60 and 90 days, respectively), T2, T5 and T8 - stratification (seeds were distributed in boxes with wet sand maintained at a temperature of 4°C for 30, 60 and 90 days, respectively), T3, T6 and T9 - scarification + stratification (seeds scarified with sandpaper n.80 and stratified by 30, 60 and 90 days, respectively), in completely random experimental design. Plant height, stem diameter, number of leaves, full emergence and emergence speed index (ESI) were evaluated... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Scarification; Stratification; Emergence; Carya illinoinensis. |
| Ano: 2016 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-84782016001101980 |
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| Morato,Elder Ferreira. |
| The effects of forest fragmentation on the patterns of vertical abundance and richness of solitary wasp and bee communities was investigated near Manaus, Amazonas. Wasps and bees were trap-nested at 1,5, 8 and 15 m above the ground in continuous primary forestand isolated forest fragments. In general, the number of nests and species increased with height for both groups. In particular, bee species richness at 15 m was almost twice that at 1,5 mm. However, one species of Trypoxylon Latreille, 1796 (Sphecidae) consistently nested in the understorey. Thus, patterns of abundance and richness distributions indicated stratification. A contingency analysis showed that fragmentation altered stratification of nesting activity of the wasp community in fragments.... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Forest fragmentation; Amazonia; Stratification; Solitary wasps; Solitary bees. |
| Ano: 2001 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0101-81752001000300010 |
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| DURIGAN,GISELDA; FRANCO,GERALDO ANTÔNIO DAHER CORRÊA; SAITO,MASAHIRO; BAITELLO,JOÃO BATISTA. |
| O estudo fitossociológico, se realizado em diferentes estratos verticais da floresta, fornece dados de grande valia para a compreensão da dinâmica da comunidade. Efetuou-se levantamento das espécies arbóreas presentes em diferentes estratos, em área de 6.000 m² de floresta madura, na Estação Ecológica dos Caetetus, Gália, SP. Foram utilizadas 60 parcelas de 10 x 10 m, para indivíduos com diâmetro do caule a 1,30 m acima do nível do solo (DAP) a partir de 5 cm (estrato superior); 10 x 2 m, para indivíduos com DAP entre 1 e 5 cm (estrato intermediário) e 60 sub-parcelas de 2 x 2 m, para indivíduos menores que 1 cm de DAP (estrato inferior). Verificou-se que a diversidade, a composição florística e a densidade relativa das espécies variam entre estratos. No... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Seasonal semideciduous forest; Phytosociology; Stratification. |
| Ano: 2000 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-84042000000400003 |
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| Defontaine, Sophie; Sous, Damien; Morichon, Denis; Verney, Romaric; Monperrus, Mathilde. |
| The present paper reports on a series of field experiments aiming to characterise the functioning of a man-engineered strongly forced salt-wedge estuary: the lower estuary of the Adour river, France. Bottom-moored velocity measurements and surface boat surveys have been performed under low river discharge conditions, for both neap and spring tides, in order to provide a well-documented reference framework to understand the dynamics of water masses, turbulence and suspended particulate matter (SPM) transport in the lower estuary. An additional campaign has been carried out in high river discharge conditions. This first documented in-situ study of the Adour lower estuary demonstrates its variability in terms of hydrological regimes, from salt-wedge to... |
| Tipo: Text |
Palavras-chave: Salt-wedge estuary; Estuarine circulation; Stratification; Turbulence; Suspended particles transport; Adour river. |
| Ano: 2019 |
URL: https://archimer.ifremer.fr/doc/00588/70049/67987.pdf |
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| LIMA NETO,IRAN E.. |
| Abstract: Field surveys and integral modelling were carried out to study the effect of bubble plumes on the flow hydrodynamics and the time-evolution of water temperature profiles in a shallow lake with maximum depth of about 4 m. Then, model simulations were performed to verify the feasibility of destratification of ten water-supply reservoirs with capacities of 10-2,000 hm3. Finally, hydrological modelling was conducted to assess the impact of destratification on evaporation suppression and its effects on reservoir yield. The results indicate that net temperature reductions of the order of 1.0°C can be obtained, which corresponds to evaporation suppressions of approximately 10%. In turn, this resulted in increases in the regulated flow of 2-12% that... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Aeration; Evaporation; Bubble plumes; Lakes; Stratification; Water yield. |
| Ano: 2019 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0001-37652019000500904 |
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| Grasso, Florent; Le Hir, Pierre. |
| Estuaries are subject to extensive morphological changes through human activities, such as deepening and narrowing via dredging and channelization. The estuary sediment load, characterised by the estuarine turbidity maximum (ETM), can severely increase in response to channel deepening, shifting the estuary from a natural to hyperturbid state. The main processes driving the estuarine circulation, hydrology and sediment dynamics are relatively well known. However, their relative influence on suspended sediment concentration (SSC), as well as their role in the transition toward hyperturbid estuaries, is still a subject of debate. Therefore, this study aims at investigating the relative contribution of key estuarine drivers (gravitational circulation and tidal... |
| Tipo: Text |
Palavras-chave: Estuary deepening and narrowing; Sediment dynamics; Turbidity maximum; Tidal asymmetry; Stratification; Numerical modelling; Morphological changes. |
| Ano: 2019 |
URL: https://archimer.ifremer.fr/doc/00479/59046/65965.pdf |
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| Łącka, Magdalena; Cao, Min; Rosell-melé, Antoni; Pawłowska, Joanna; Kucharska, Małgorzata; Forwick, Matthias; Zajączkowski, Marek. |
| The increasing influence of Atlantic Water (AW) in the Barents Sea, a process known as “Atlantification”, is gradually decreasing sea ice cover in the region. Ongoing global climate warming is likely to be one of its drivers, but to further understand the role of natural variability and the biogeochemical impacts of the inflow of AW into the western Barents Sea, we reconstructed sea surface temperatures (SSTs) and primary productivity in Storfjordrenna, a climatically sensitive area south of Spitsbergen, between approximately 13,950 cal yr BP and 1300 cal yr BP. The alkenone proxy has been applied to reconstruct SSTs, and the alkenone accumulation rate in marine sediments has been used to infer changes in primary productivity. Our data show that the SST... |
| Tipo: Text |
Palavras-chave: Alkenones; Stratification; Holocene; Sea ice decrease; Global warming; North Atlantic Current; Arctic. |
| Ano: 2019 |
URL: https://archimer.ifremer.fr/doc/00585/69740/67629.pdf |
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| Registros recuperados: 35 | |
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