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871.
Gilad Heinisch Aldo Corriero Antonio Medina Francisco J. Abascal Jose-Miguel de la Serna Robert Vassallo-Agius Antonio Belmonte Ríos Antonio García Fernando de la Gándara Christian Fauvel Christopher R. Bridges Constantinos C. Mylonas Saadet F. Karakulak Isik Oray Gregorio De Metrio Hanna Rosenfeld Hillel Gordin 《Marine Biology》2008,154(4):623-630
Atlantic bluefin tuna (BFT; Thunnus thynnus) is a migrating species straddling the North Atlantic Ocean and Mediterranean Sea. It is assumed that this species is divided
into a western and an eastern stock, which spawn in the Gulf of Mexico and the Mediterranean Sea, respectively. To learn more
about the reproductive behavior of the eastern BFT stock, we tracked gonadal development in adult fish that were sampled between
April and July during three consecutive years (2003–2005). Sampling campaigns were carried out using common fishing methods
at selected locations within the Mediterranean Sea, namely Levantine Sea, Malta, and Balearic Islands. An additional sampling
point, Barbate, was situated northwest of the Straits of Gibraltar along the Atlantic coast. Morphometric parameters such
as the total body mass (M
B) and the weights of the gonads (M
G) were recorded, and the respective gonadosomatic index (GSI) values were calculated. The data collected revealed two important
trends: (1) GSI values are higher in fish caught in the eastern rather than the western locations across the Mediterranean
Sea, and (2) the GSI reaches maximum values between late May and early June in Levantine Sea (eastern Mediterranean Sea),
and only 2 and 4 weeks later in the central (Malta) and western (Balearic Islands) locations, respectively. The advanced gonadal
development in BFT correlates well with higher sea surface temperatures. Our findings also distinguish the northern Levantine
Sea BFT population (mean M
B 78.41 ± 4.13 kg), and the Barbate BFT population with the greatest M
B (all fish sampled > 100 kg). These data reflect a situation in which the eastern Mediterranean basin may function as a habitat
for young BFT, until they gain a larger M
B and are able to move to the Atlantic Ocean. However, the existence of genetically discrete BFT populations in the Mediterranean
Sea cannot be ruled out. 相似文献
872.
José Fortes Lopes Ana Cristina Cardoso Maria Teresa Moita Alfredo C. Rocha Juan A. Ferreira 《Ecological modelling》2009
The main objective of this paper is to implement a coupled three-dimensional physical and ecological model for the Aveiro coast, and to apply it to study the temperature and the phytoplankton biomass spatial distributions along the coastal ecosystem. The Aveiro coast is located at Portugal within the upwelling system of the Atlantic Iberian coast, characterized by nutrients availability and phytoplankton biomass accumulation, from April to October. In order to implement the ecological model, its validation was assessed by comparing simulations to data relative to the horizontal and vertical distributions of the temperature, nutrients and phytoplankton biomass, obtained during the CICLOS I survey off the Portuguese coast [Moita, M.T., 2001. Estrutura, Variabilidade e Dinâmica do Fitoplâncton na Costa de Portugal Continental. PhD Thesis. Faculdade de Ciências da Universidade de Lisboa, 272 pp.]. A sensitivity analysis of the model has been performed in order to assess the influence of the main ecological model variables. The simulation results show that the model is capable of predicting realistic the temperature, the nutrients and the chlorophyll-a distributions for the study area. The scenarios evidence the setup of a thermal stratification pattern resulting from the upwelling of deep and rich in nutrients water to the surface layer and a chlorophyll-a maxima extending offshore, along the picnocline and the nutricline. The results confirm the crucial role played by the physical processes in the phytoplankton bloom along the Aveiro coast. They also evidence the close link between the surface phytoplankton distribution and the surface temperature distribution. 相似文献
873.
Marcela González Cristina Dapeña Bibiana Cerne Odon Sánchez-Ccoyllo Saulo Freitas Pedro L. Silva Dias Héctor Panarello 《Environmental Fluid Mechanics》2009,9(4):409-425
The SALLJEX experiment was held during the summer 2002–2003. It consisted of three-dimensional observation of the atmosphere
to study the structure of the low level jet along the eastern slopes of the Andes. Daily precipitation water samples were
collected at two stations (Resistencia and Salta) in northern Argentina and isotope content was analyzed. The isotope data
were used in conjunction with air parcel trajectories obtained from a 3-D kinematic model (3D-MTC) developed by the University
of Sao Paulo, Brazil. Values of deuterium excess were related with air masses of continental origin, whilst low values were
associated with air masses with longer oceanic trajectories. Furthermore, although data are scarce, results show that oxygen-18
and deuterium excess in rainwater are related with the occurrence of the low level jet. 相似文献
874.
de Guzmán Báez A Villoria Sáez P del Río Merino M García Navarro J 《Waste management (New York, N.Y.)》2012,32(5):920-924
In the last years, the European Union (EU) has been focused on the reduction of construction and demolition (C&D) waste. Specifically, in 2006, Spain generated roughly 47million tons of C&D waste, of which only 13.6% was recycled. This situation has lead to the drawing up of many regulations on C&D waste during the past years forcing EU countries to include new measures for waste prevention and recycling. Among these measures, the mandatory obligation to quantify the C&D waste expected to be originated during a construction project is mandated. However, limited data is available on civil engineering projects. Therefore, the aim of this research study is to improve C&D waste management in railway projects, by developing a model for C&D waste quantification. For this purpose, we develop two equations which estimate in advance the amount, both in weight and volume, of the C&D waste likely to be generated in railway construction projects, including the category of C&D waste generated for the entire project. 相似文献
875.
Correlation analysis between sulphate content and leaching of sulphates in recycled aggregates from construction and demolition wastes 总被引:1,自引:0,他引:1
Barbudo A Galvín AP Agrela F Ayuso J Jiménez JR 《Waste management (New York, N.Y.)》2012,32(6):1229-1235
In some recycled aggregates applications, such as component of new concrete or roads, the total content of soluble sulphates should be measured and controlled. Restrictions are usually motivated by the resistance or stability of the new structure, and in most cases, structural concerns can be remedied by the use of techniques such as sulphur-resistant cements. However, environmental risk assessment from recycling and reuse construction products is often forgotten. The purpose of this study is to analyse the content of soluble sulphate on eleven recycled aggregates and six samples prepared in laboratory by the addition of different gypsum percentages. As points of reference, two natural aggregates were tested. An analysis of the content of the leachable amount of heavy metals regulated by European regulation was included. As a result, the correlation between solubility and leachability data allow suggest a limiting gypsum amount of 4.4% on recycled aggregates. This limit satisfies EU Landfill Directive criteria, which is currently used as reference by public Spanish Government for recycled aggregates in construction works. 相似文献
876.
Composition of plastics from waste electrical and electronic equipment (WEEE) by direct sampling 总被引:1,自引:0,他引:1
This paper describes a direct analysis study carried out in a recycling unit for waste electrical and electronic equipment (WEEE) in Portugal to characterize the plastic constituents of WEEE. Approximately 3400 items, including cooling appliances, small WEEE, printers, copying equipment, central processing units, cathode ray tube (CRT) monitors and CRT televisions were characterized, with the analysis finding around 6000 kg of plastics with several polymer types. The most common polymers are polystyrene, acrylonitrile-butadiene-styrene, polycarbonate blends, high-impact polystyrene and polypropylene. Additives to darken color are common contaminants in these plastics when used in CRT televisions and small WEEE. These additives can make plastic identification difficult, along with missing polymer identification and flame retardant identification marks. These drawbacks contribute to the inefficiency of manual dismantling of WEEE, which is the typical recycling process in Portugal. The information found here can be used to set a baseline for the plastics recycling industry and provide information for ecodesign in electrical and electronic equipment production. 相似文献
877.
Collection and recycling of electronic scrap: a worldwide overview and comparison with the Brazilian situation 总被引:1,自引:0,他引:1
Recycling and the related issue of sustainable development are increasing in importance around the world. In Brazil, the new National Policy on Solid Wastes has prompted discussion on the future of electronic waste (e-waste). Over the last 10 years, different e-waste collection systems and recycling processes have been applied globally. This paper presents the systems used in different countries and compares the world situation to the current Brazilian reality. To establish a recycling process, it is necessary to organize efficient collection management. The main difficulty associated with the implementation of e-waste recycling processes in Brazil is the collection system, as its efficiency depends not only on the education and cooperation of the people but also on cooperation among industrial waste generators, distributors and the government. Over half a million waste pickers have been reported in Brazil and they are responsible for the success of metal scrap collection in the country. The country also has close to 2400 companies and cooperatives involved in recycling and scrap trading. On the other hand, the collection and recycling of e-waste is still incipient because e-wastes are not seen as valuable in the informal sector. The Brazilian challenge is therefore to organize a system of e-waste management including the informal sector without neglecting environmentally sound management principles. 相似文献
878.
J M López-Gutiérrez M García-León C Schnabel M Suter H A Synal S Szidat 《Journal of environmental radioactivity》2001,55(3):269-282
Iodine-129 (T1/2 = 1.57 x 10(7) yr) concentrations have been determined by accelerator mass spectrometry in rainwater samples taken at Seville (southwestern Spain) in 1996 and 1997. This technique allows a reduction in the detection limits for this radionuclide in comparison to radiometric counting and other mass spectrometric methods such as ICP-MS. Typical 129I concentrations range from 4.7 x 10(7) 129I atoms/l (19.2%) to 4.97 x 10(9) 129I atoms/l (5.9%), while 129I depositions are normally in the order of 10(8)-10(10) atoms/m2d. These values agree well with other results obtained for recent rainwater samples collected in Europe. Apart from these, the relationship between 129I deposition and some atmospheric factors has been analyzed, showing the importance of the precipitation rate and the concentration of suspended matter in it. 相似文献
879.
Extractable atrazine and its metabolites (hydroxyatrazine, deethylatrazine and deisopropylatrazine) were evaluated in agricultural
soils from the temperate humid zone (Galicia, NW Spain) under laboratory conditions. The experiment was performed with five
soils with different properties (organic C, soil texture and atrazine application history), both unamended and treated with
atrazine at field application rate. Measurements of the atrazine compounds were made at different time intervals (1, 3, 6,
9 and 12 weeks) during a 3-month incubation period. Results showed that only hydroxyatrazine was detected in the extractable
fraction of the unamended soils, with values remaining relatively constant throughout the incubation period. Atrazine addition
notably increased the concentration of the parent compound and its degradation products; deisopropylatrazine and hydroxyatrazine
were the main metabolites detected in the extractable fraction of the treated soils, whereas deethylatrazine was not detected.
After 7 days incubation, values of total extractable residues, expressed as percentage of initially added atrazine, ranged
from 75 to 86% (25–68% of atrazine, 7–11% of hydroxyatrazine and 9–57% of deisopropylatrazine). The values decreased rapidly
during the first 3 weeks of incubation, showing values of 2–8% in soils with higher atrazine application and from 28 to 30%
in soils with lower application history. At the end of the incubation, 2–8% of total extractable residues were still detected
(0–4% of atrazine, 2–3% of hydroxyatrazine and 0–2% of deisopropylatrazine), indicating a residual effect of atrazine addition.
These variations in the extractable fraction indicated that most added atrazine was rapidly degraded, especially in soils
with higher application history. 相似文献
880.
Carlos César Martínez-Rivera H. Carl Gerhardt 《Behavioral ecology and sociobiology》2008,63(2):195-208
Senders and receivers influence dynamic characteristics of the signals used for mate attraction over different time scales.
On a moment-to-moment basis, interactions among senders competing for a mate influence dynamic characteristics, whereas the
preferences of receivers of the opposite gender exert an influence over evolutionary time. We observed and recorded the calling
patterns of the bird-voiced treefrog Hyla avivoca to assess how the dynamic characters of calls vary during interactions among groups of males in a chorus. This question was
also addressed using playback experiments with males. Playback experiments with females showed how changes in dynamic call
properties are likely to affect male mating success. Frogs calling in pairs, groups, or in response to playbacks produced
longer calls than did isolated males. During call overlap, males often increased the duration of the silent interval (gaps)
between the pulses of their calls so that the pulses of the calls of two neighbors interdigitated. This change resulted in
increased variability of pulse rate, a traditionally static acoustic property; however, males also produced high proportions
of non-overlapped calls in which variability in pulse rate was low and had species-typical values. Females preferred long
calls to short- and average-duration calls, and non-overlapped calls to overlapped calls. Given a choice between pairs of
overlapped calls, females preferred pairs in which the proportion of overlap was low and pairs in which the pulses of such
calls interdigitated completely. The observed patterns of vocal competition thus reflect the preferences of conspecific females,
which have influenced the evolution of the calling behavior of H. avivoca.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献