Ideal width of transects for monitoring source-related categories of plastics on beaches     

de Araújo MC  Santos PJ  Costa MF 《Marine pollution bulletin》2006,52(8):957-961

Although there is a consensus on the necessity of monitoring solid wastes pollution on beaches, the methods applied vary widely. Therefore, creating, testing and recommending a method that not only allows comparisons of places and periods, but also the detection of source signals, will be important to reach the objectives of the source-prevention principle. This will also allow the optimisation of time, resources, and processing of samples and data. A classification of the items found into specific categories was made according to their most probable source/use (fisheries, food packaging, hazardous, sewage/personal hygiene, beach user, general home). This study tested different widths of sampling transects to be used in the detection of plastics contamination on beaches, until all the categories were significantly represented. Each transect had its total width (50m) sub-divided into eight intervals of 0-2.5m; 2.5-5m; 5-10m; 10-15m; 15-20m; 20-30m; 30-40m; and 40-50m. The accumulated number of categories in the 50m (up to 2.5m; up to 5m and so on) was used to determine the minimal width necessary to qualitatively characterize the area regarding plastics contamination. The diversity of the categories was directly related to the area of the sampling transect. These results indicate that a significant increase in the number of categories in the first intervals tend to stabilize from 15-20m onwards.  相似文献   

Effects of the number of stations and time resolution on derivation     

Odim Mendes  Jr.  Aracy Mendes da Costa  Fernando Celso Perin Bertoni 《Journal of Atmospheric and Solar》2006,68(18):2127-2137

For at least 30 years now it has been well known that the Dst index can be modelled using the solar wind as input. Since then, many attempts have been made to improve the predictability of Dst using different approaches. These attempts are useful, for instance, to understand which features of the solar wind–magnetosphere interactions are most important in producing magnetospheric activity and how the Dst index would improve the space weather forecast. The Dst index is by far the most reliable and simple indication that a magnetic storm is in progress. In this work, the effect of using more than four magnetic stations and shorter time intervals than the hourly averages used in Sugiura's procedures is evaluated. The discussion is based on the results presented by Burton in 1975 and Feldstein in 1984 considering 4 or 12 magnetic stations and time averages of 2.5 min for a magnetic disturbed period that occurred from February 7–28, 1967, including two geomagnetic storms. The analysis has shown that the global representation of a magnetic storm by the standard Dst (Sugiura) is well preserved either using 4, 6, 12 magnetic stations or using 1 h, 2.5 min 1 min averages. A brief review of the current understanding of Dst has been included to support the discussions. The analysis performed has shown that a more refined Dst index (time and number of stations>4) would be useful to investigate the intrinsic processes and the different current systems involved in the ring current development during magnetic storms; the standard Dst, as it is conceived, is quite adequate to monitor geomagnetic storms and identify their overall features; concerning the magnetic stations normally considered, the inclusion of higher magnetic latitude stations (>35) may underestimate the observed Dst.  相似文献   

Erratum to: Mission design,operation and exploitation of the Gravity field and steady-state Ocean Circulation Explorer (GOCE) mission     

Rune?FloberghagenEmail author  Michael?Fehringer  Daniel?Lamarre  Danilo?Muzi  Bj?rn?Frommknecht  Christoph?Steiger  Juan?Pi?eiro  Andrea?da?Costa 《Journal of Geodesy》2012,86(3):241-241

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Influence of high-pressure processing on the structure and memory effect of synthetic layered double hydroxides     

Jaqueline C. Rodrigues  Tania Maria Haas Costa  Márcia R. Gallas  Celso C. Moro 《Physics and Chemistry of Minerals》2009,36(8):439-446

We investigate the structural evolution of synthetic layered double hydroxides (LDH) samples, processed at room temperature and high-pressure (up to 7.7 GPa) in a toroidal chamber with two pressure-transmitting media, lead and graphite, using X-ray diffraction, thermogravimetry and N₂-adsorption isotherms techniques. The X-ray patterns of compacted samples show a decrease in the peak intensities. For both pressure-transmitting media, our samples revealed a reduction of the basal d-spacing for the (003) plane when processed at 7.7 GPa. The expected high-pressure-induced amorphization was not observed. Surprisingly, we find high-pressure processing to have a strong influence on the memory effect of the LDH, due essentially to the reduction of the surface area and pore closing. Even when immersed in water, our samples did not recover the LDH structure, when either calcined at 450°C and compacted at 7.7 GPa, or calcined at 700°C and immediately compacted at 2.5 and 7.7 GPa.  相似文献   

Investigating Ionospheric Scintillation Effects on Multifrequency GPS Signals     

Salles  Lucas A.  Vani  Bruno C.  Moraes  Alison  Costa  Emanoel  de Paula  Eurico R. 《Surveys in Geophysics》2021,42(4):999-1025

Surveys in Geophysics - Over the last 15 years, the satellite constellation of the global positioning system (GPS) has been modernized for more precise applications, with the introduction...  相似文献   

Correction to: Spatial distribution and estimation of rainfall trends and erosivity in the Epitácio Pessoa reservoir catchment,Paraíba,Brazil     

da Silva  Richarde Marques  Santos  Celso Augusto Guimarães  Silva  Jorge Flávio Casé Braga da Costa  Silva  Alexandro Medeiros  Brasil Neto  Reginaldo Moura 《Natural Hazards》2020,104(2):1953-1954

Natural Hazards - The article “Spatial distribution and estimation of rainfall trends and erosivity in the Epitácio Pessoa reservoir catchment, Paraíba, Brazil”, written by da...  相似文献   

The Cabo Frio upwelling overrides geographical patterns in the population dynamics of the shrimp Artemesia longinaris Spence Bate, 1888 (Decapoda: Penaeidae)     

Abner Carvalho‐Batista  Joo Alberto Farinelli Pantaleo  Antonio Leo Castilho  Rogrio Caetano da Costa 《Marine Ecology》2019,40(2)

Upwelling areas are among the most productive ecosystems on the planet, influencing the biology of marine organisms. This study investigated the population dynamics of the shrimp Artemesia longinaris in two regions in southeastern Brazil, one inside (Macaé—Rio de Janeiro State) and one outside (Ubatuba—State of São Paulo) the Cabo Frio upwelling area. The aim was to verify the influence of the upwelling phenomenon on the abundance, growth, longevity, size of sexual maturity, and reproductive period of the species. In total, 188,902 individuals were captured at Macaé and 3,461 at Ubatuba. Individuals captured at Macaé showed larger maximum size, higher longevity, and slower growth rate, besides reaching sexual maturity at larger sizes than at Ubatuba. Continuous reproduction was observed in both regions, with juvenile recruitment peaks in spring and summer. Local conditions observed at Macaé were influenced by the Cabo Frio upwelling zone, characterized by productive and cooler waters that are around 20°C during most of the year. The upwelling phenomenon is probably the main factor influencing the population parameters studied here, changing the geographic patterns previously observed for the variation of these parameters in A. longinaris.  相似文献   

Multiple Random Walk Simulation: A Fast Method to Map Grade Uncertainty with Large Datasets     

Rafael Moniz Caixeta  Diniz Tamantini Ribeiro  João Felipe Coimbra Leite Costa  Péricles Lopes Machado 《Natural Resources Research》2017,26(2):213-221

Multiple Random Walk Simulation consists of a methodology adapted to run fast simulations if close-spaced data are abundant (e.g., short-term mining models). Combining kriging with the simulation of random walks attempts to approximate traditional simulation algorithm results but at a computationally faster way when there is a large amount of conditioning samples. This paper presents this new algorithm illustrating the situations where the method can be used properly. A synthetic study case is presented in order to illustrate the Multiple Random Walk Simulation and to analyze the speed and goodness of its results against the ones from using Turning Bands Simulation and Sequential Gaussian Simulation.  相似文献   

Estuarine and coastal connectivity of an estuarine-dependent fishery species,Pomadasys commersonnii (Haemulidae)     

MH Dames  PD Cowley  A-R Childs  RH Bennett  EB Thorstad  TF Næsje 《African Journal of Marine Science》2017,39(1):111-120

Understanding the level of connectivity between estuarine and coastal waters is essential for appropriate management of estuarine-associated taxa. Most studies have focused on the role of a single estuary, while limited research exists on the importance of multiple estuaries to individuals of estuarine-associated species. This study used acoustic telemetry to assess the usage of multiple estuaries and coastal waters by the estuarine-dependent spotted grunter Pomadasys commersonnii. Twenty-six adult fish were tagged with acoustic transmitters in the Kariega and Bushmans estuaries, South Africa, and their movements along a 300-km stretch of Indian Ocean coastline were monitored for up to 17 months. Tagged individuals spent most of their time in the estuary where they were tagged (55% and 85% for fish tagged in the two estuaries, respectively), followed by time in the sea (30% and 15%) and in other estuaries (15% and <1%). The mean durations of sea trips for fish tagged in the Kariega Estuary or Bushmans Estuary, respectively, were 25 days (range 3–55) and 12 days (range 2–22). Of the fish that went to sea, 93% from the Kariega Estuary and 60% from the Bushmans Estuary visited other estuaries. Most visits were undertaken to the Swartkops, Bushmans and Kowie estuaries, although the longest durations were spent in the Sundays Estuary. Individuals moved to estuaries up to 130 km away. The total distance travelled between estuaries by an individual during the study was ～529 km, with means of 201 and 184 km, respectively, for fish tagged in the Kariega and Bushmans estuaries. Despite covering large distances between estuaries, individuals often returned to their tagging estuary. Residency in their tagging estuary, combined with frequent visits to a neighbouring estuary, highlights the importance of estuarine habitats for this popular fish species, even after reaching maturity.  相似文献   

Investigating the molecular systematic relationships amongst selected Plesionika (Decapoda: Pandalidae) from the Northeast Atlantic and Mediterranean Sea     

Joana M da Silva  Antonina dos Santos  Marina R Cunha  Filipe O Costa  Simon Creer  Gary R Carvalho 《Marine Ecology》2013,34(2):157-170

Despite the high number of species and ecological diversity of pandalid shrimps, there has been no previous attempt to resolve evolutionary relationships of several genera using molecular tools. Although mitochondrial DNA cytochrome oxidase I (COI) is widely used in barcoding studies to delimit species boundaries, additional insights into phylogenetic affinities can be obtained, especially when used in combination with data from additional genes. The knowledge of molecular diversity is essential to understand phylogenetic relationships and will help systematic clarifications. Based on partial fragments of the 16S and COI genes, we have focused specifically on addressing the systematic relationships of the economically and ecologically important shrimp genus Plesionika within a framework of five genera from within the Pandalidae. Our results showed that species within Plesionika are substantially divergent when compared with other genera, exhibiting the highest average nucleotide divergence, with 0.1123 and 0.0846 in COI and 16S genes, respectively. In addition, sequence divergence was found to vary greatly within the genus Plesionika (COI/16S): 0.0247/0.0016 between Plesionika antigai and Plesionika heterocarpus and 0.1616/0.098 between Plesionika heterocarpus and Plesionika edwardsii. We did not find amino acid sequence divergence between P. heterocarpus and P. antigai compared with P. heterocarpus and P. edwardsii (8.10%, K2P distance). Three species of Plesionika (P. antigai, P. heterocarpus and Plesionika scopifera) appear well separated from other Plesionika species in both maximum likelihood and Bayesian analyses. The present study confirms the utility of COI over 16S as a genetic marker to resolve relationships between different species of Plesionika from the Northeast Atlantic and Mediterranean Sea, in addition to species delimitation. The findings highlight the need to further review paraphyly within Plesionika in an attempt to recognize a concordance in the evolutionary history of Plesionika with major ecological and geological events.  相似文献