170,169 research outputs found
Toxicity of untreated wood leachates towards two saltwater organisms (Crassostrea gigas and Artemia franciscana)
No full textWood is widely used in the development of freshwater, estuarine and marine coastlines. Timbers last according to their content of naturally occurring preservatives (mostly phenols and aldehydes), produced to prevent decay from biotic agents. When untreated woods are exposed to aquatic media, leachates are generated with likely toxic effects on the target environment. The potential impact on saltwaters of leachates from some untreated timbers of both native and tropical species has been assessed. The leaching procedure was set up considering British Standard test methods for paints and OECD guidelines for wood preservatives emission scenarios. Toxicity was monitored via the acute toxicity test with the brine shrimp Artemia franciscana and the sub-chronic embryotoxicity test with the oyster Crassostrea gigas. Brine shrimps evidenced no toxic effects while oysters discriminated well among leachates: the tropical wood species showed similar or relatively lower toxic effects than the native ones according to both leaching cycles (24 and 72 h). The ecotoxicological data have been integrated with some physical and chemical parameters
Influence of storage methods, refrigeration or freezing, on the toxicity of wastewater samples to oyster embryos
No full textOne of the main concerns in wastewater whole effluent assessment is the sampling phase and the sample chain of custody before any toxicity evaluation. The major problem is related to establishing the correct method for sample storage in order to perform toxicity bioassays. The toxicity of some domestic and glass factory industrial wastewater samples stored both by refrigeration at 4 ± 1°C for no more than three days, and freezing at -18 ± 1°C for no more than one month was compared via the embryo larval development bioassay with the oyster Crassostrea gigas. The results showed no significant differences between the toxicities of refrigerated and frozen wastewater samples. The wastewater classification, according to a score based on four toxicity classes, showed that the preservation methods did not alter the toxicity classification of the samples. In particular, it was demonstrated that the samples considered as 'not acutely toxic' after refrigeration were also found to have this classification after freezing
Influence of the salinity adjustment methods, salts and brine, on the toxicity of wastewater samples to mussels embryos.
No full textOne of the main problems of the Whole Effluent Toxicity is related to the use of bioindicator species representative of the target environment. Most wastewater discharges are of fresh water, so their salinity has to be adjusted when they are discharged to transitional and marine coastal waters, in order to perform toxicity bioassays with reliable organisms. At the moment, there is no optimum technique to allow sample salinity to be adjusted and no specific information regarding salinity adjustment when bivalves are being considered for toxicity test performance. This paper provides information on the potential use of different methods to adjust the salinity of hotel/domestic wastewater samples with different brands of natural and synthetic Dry Salts (DS) and HyperSaline Brine (HSB) for use in the embryo larval development bioassay with the mussel Mytilus galloprovincialis. HyperSaline Brine derived from reconstructed artificial seawater proved to be more viable for wastewater salinity adjustment than DS
Breve panorama a respeito das principais teorias da política e das relações internacionais
No full textO presente trabalho explora as principais teorias que embasam a política e as relações internacionais, oferecendo uma visão geral das abordagens tradicionais e contemporâneas. O ponto de partida para a pesquisa foi o Tratado de Vestfália, assinado em 1648, que além de decretar o final de um período de guerra, também propiciou os fundamentos para um novo sistema internacional. A partir do referido Tratado, foi possível compreender o conceito moderno de Estado e a importância de sua soberania. Nessa ótica, foram estudadas as seguintes teorias: Idealismo Clássico e Moderno, Realismo Contemporâneo, Liberalismo, Escola Inglesa, Teoria da Dependência, Teoria Crítica, Construtivismo e Pós-Colonialismo A conclusão da abordagem é no sentido de reconhecer a diversidade teórica, que pode, inclusive, ser campo fértil para o para o desenvolvimento de novas teorias.The present work explores the main theories underpinning politics and international relations, offering an overview of both traditional and contemporary approaches. The starting point for the research was the Treaty of Westphalia, signed in 1648, which not only marked the end of a period of war but also laid the foundations for a new international system. From this Treaty, it was possible to understand the modern concept of the State and the importance of its sovereignty. In this perspective, the following theories were studied: Classical and Modern Idealism, Contemporary Realism, Liberalism, the English School, Dependency Theory, Critical Theory, Constructivism, and Post-Colonialism. The conclusion of the approach is to recognize the theoretical diversity, which can even be a fertile ground for the development of new theories
LOW CAROTID ARTERIAL STIFFNESS IN YOUNG TYPE1 DIABETIC PATIENTS COMPARED WITH AGE-MATCHED CONTROLS
No full textBackground: Local pulse wave velocity (c) is widely used as an index of local carotid arterial stiffness. In middle-aged type1 and type2 diabetic patients, arterial stiffness is higher than in healthy people, but much less data are available for young subjects. Our aim was to quantify the changes in c asso- ciated with ageing and type1 diabetes in young patients. Methods: Pressure and diameter waveforms of healthy control (n Z 53, 29 male, mean age 39 ` 17) and type1 diabetic (n Z 20, 15 male, mean age 19 ` 2.5) subjects have been acquired simultaneously using tonometry (500 or 1000Hz) and an ultrasound probe (1kHz) at the level of the left and right common carotid artery, respectively. The geometrical similarity between the right and left common carotid artery was verified, and the two signals were assumed as recorded at the same site. The PD2-loop method [1] was used to calculate c in late diastole as follow: c Z D0dPr d(D2). Results: In controls, c remained approximately constant up to ages 35e44y, at `4 m/s. From 45e54 years old, c increased up to 7m/s in elderly subjects (figure1-left). In young diabetic subjects (15e24), c was lower than in aged- matched control subjects (mean `95% C.I., diabetic 3.51 ` 0.007 and con- trol 3.78 ` 0.005, p < 0.05) (figure1-right). Conclusions: Local stiffness increases with age in the human carotid artery. As found for the descending thoracic aorta previously[2], younger T1 diabetic patients may have more compliant vessels initially, aggravating their ten- dency to stiffen later
Overview on ecotoxicological studies performed in the Venice Lagoon (Italy)
No full textThis work reports on the state of the art of the bioindicators used to assess environmental quality (regarding
chemical pollutant impacts) in the Venice lagoon. After a brief description of the roles, advantages and limitations
of bioindicators inmarine and transitional environments and a summary of the Venice lagoon characteristics, the
ecotoxicological methods used during scientific studies and research projects in the Lagoon are reported. Since
not all data are available and no database can be formulated, the main evidence from toxicity bioassays,
biomarkers and bioaccumulation analyses since the end of the 1970s is spatially synthesized using maps and
discussed according to the four Venice lagoon basins. The majority of indicators showed that the Lido basin
(north-central lagoon), affected by the presence of the industrial area and the city ofVenice, is the onemost highly
impacted (particularly in the sites located within or in front of the industrial area, which showed very high
sediment toxicity and high levels of DNA damage). The Malamocco basin (south-central lagoon) seems to be the
least problematic. The southern basin (Chioggia basin) was shown to be impacted by urban contaminants from
the town of Chioggia. The northern basin (Treporti basin) presented both impacted sites (high toxicity and high
bioaccumulation factor) and relatively unpolluted sites (absence of toxicity, absence of imposex and lowlevels of
bioaccumulation). This review can serve as a basis on which to select pragmatic, cost-effective biomonitoring
techniques for environmental effects in lagoon ecosystems
Influence of storage methods, refrigeration or freezing, on the toxicity of wastewater samples to oyster embryos.
No full textOne of the main concerns in wastewater whole effluent assessment is the sampling phase and the sample chain of custody before any toxicity evaluation. The major problem is related to establishing the correct method for sample storage in order to perform toxicity bioassays. The toxicity of some domestic and glass factory industrial wastewater samples stored both by refrigeration at 4 ± 1°C for no more than three days, and freezing at -18 ± 1°C for no more than one month was compared via the embryo larval development bioassay with the oyster Crassostrea gigas. The results showed no significant differences between the toxicities of refrigerated and frozen wastewater samples. The wastewater classification, according to a score based on four toxicity classes, showed that the preservation methods did not alter the toxicity classification of the samples. In particular, it was demonstrated that the samples considered as 'not acutely toxic' after refrigeration were also found to have this classification after freezing
Saggio di embriotossicità con Mytilus galloprovincialis per gli ambienti di transizione.
No full text
Going Beyond Counting First Authors in Author Co-citation Analysis
No full textThe 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
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