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Signature whistle variations in a bottlenosed dolphin,Tursiops truncatus   总被引:1,自引:0,他引:1  
To examine whether context-specific information is superimposed upon the individual cues present in the whistling of the bottlenosed dolphin, Tursiops truncatus, parameter variations within the two most frequently emitted whistle types of a captive individual were investigated in three different behavioural contexts. The study concentrated on comparing signal features of spontaneously occurring vocalizations in two possible phases following the performance of a trained discrimination task and those occurring during isolation. Phases of the discrimination task differed according to whether the animal showed correct (reward given) or incorrect performance (no reward). Signature whistles were most common in isolation, but also represented just over half of the whistles following a choice task. Of 14 signature whistle frequency and time parameters measured 9 differed significantly between isolation and at least one of the phases following a choice task (Table 1). Three parameters also varied according to whether performance was correct or incorrect. In contrast, only one out of four parameters (start frequency) measured from the second most frequent whistle type varied significantly between contexts (isolation vs. phase following correct choice). The results indicate that not only identity but also context-related information is available in the whistles of a bottlenosed dolphin.  相似文献   
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This paper is an investigation of the polymer degradation process in two types of seawater (with and without microorganisms) sourced from the Baltic Sea. The chosen polymeric materials were polycaprolactone modified with either thermoplastic starch (PCL/TPS?>?85%) or calcium carbonate (60% PCL/40% CaCO3) compared directly against unmodified polycaprolactone. All samples were incubated for 28?weeks in seawater with and without microorganisms under laboratory conditions and analysed before and after the degradation process. Weight loss analysis, microscopic observations of polymer surfaces and tensile strength tests were used to determine the progress of polymer degradation. The experimental results obtained indicated, that in each of the experiments, degradation of tested polymeric samples occured. The process was more effective in seawater with microorganisms compared against systems without added microorganisms. The experiment in seawater demonstrated that modification of PCL with calcium carbonate did not encourage the degradation process; and in some circumstances inhibited it.  相似文献   
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Progress in used tyres management in the European Union: A review   总被引:1,自引:0,他引:1  
The dynamic increase in the manufacture of rubber products, particularly those used in the automobile industry, is responsible for a vast amount of wastes, mostly in the form of used tyres, of which more than 17 million tonnes are produced globally each year. The widely differing chemical compositions and the cross-linked structures of rubber in tyres are the prime reason why they are highly resistant to biodegradation, photochemical decomposition, chemical reagents and high temperatures. The increasing numbers of used tyres therefore constitute a serious threat to the natural environment. The progress made in recent years in the management of polymer wastes has meant that used tyres are starting to be perceived as a potential source of valuable raw materials. The development of studies into their more efficient recovery and recycling, and the European Union's restrictive legal regulations regarding the management of used tyres, have led to solutions enabling this substantial stream of rubber wastes to be converted into energy or new polymer materials. In this article we present the relevant literature describing innovative organizational approaches in the management of used tyres in the European Union member countries and the possible uses of waste tyres as a source of raw materials or alternative fossil fuels.  相似文献   
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Several new biodegradable polymer materials have recently come onto the global market. Mostly the results on degradation kinetic studies are presented. This paper suggests using one of the tests to estimate the impact of polymer packaging material on sea life. The microorganism chosen was Anabaena variabilis (identified in many waters, including those of the Baltic Sea, especially in the Gulf of Gdańsk and Puck Bay; this cyanobacterium has a tendency to move with deep-sea waters causing algal blooms that upset the ecological balance of the marine environment [1]). The chosen polymer materials were polycaprolactone modified with thermoplastic starch (PCL/TPS > 85%) or with calcium carbonate (60% PCL/40% CaCO3). They were incubated in seawater in the presence of A. variabilis. The chlorophyll a content was determined as the criterion of cyanobacterial growth in the presence of the tested polymers. The polymer surface and colour changes in the cyanobacterium culture were recorded photographically. The experimental results indicate that the addition of polymer samples to the cyanobacterium culture affects its biological balance. During the experiment in seawater, cyanobacteria adhered to the polymer surfaces and their growth was stimulated to different degree by the polymers. Thus, the suggested test differentiate the behaviour of both materials studied. Cyanobacterial growth was lower in the presence of PCL modified with calcium carbonate than in the presence PCL/TPS blend.  相似文献   
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The purpose of this study was to investigate radon in the vicinity of geologic fault zones within the Krakow region of Poland, and to determine the influence of such formations on enhanced radon concentrations in soil. Radon ((222)Rn and (220)Rn) concentration measurements in soil gas (using ionization chamber AlphaGUARD PQ2000 PRO and diffusion chambers with CR-39 detectors), as well as radioactive natural isotopes of radium, thorium and potassium in soil samples (using gamma ray spectrometry with NaI(Tl) and HPGe detectors), were performed. Site selection was based on a geological map of Krakow. Geophysical methods (ground penetrating radar and shallow acoustic seismic) were applied to recognize the geological structure of the area and to locate the predicted courses of faults. Elevated levels of radon and thoron in soil gas were found in the study area when compared with those observed in an earlier survey covering Krakow agglomeration. For (222)Rn, the arithmetic mean of registered concentration values was 39 kBq/m(3) (median: 35.5 kBq/m(3)). For (220)Rn, the arithmetic mean was 10.8 kBq/m(3) and median 11.8 kBq/m(3).  相似文献   
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The measurement campaigns have been done in the rural community of Niska Banja, a spa town located in southern Serbia, to evaluate population exposure to natural radioactivity. After a screening survey in 200 houses, annual radon and thoron concentrations were measured in 34 houses, and in 2004 a detailed investigation was carried out at six houses with elevated indoor radon concentrations. The paper presents the results of these detailed measurements. The complementary techniques were applied to determine radon and thoron concentrations in indoor air, in soil gas, radon exhalation from soil, soil permeability, and indoor and outdoor gamma doses. Soil and water samples were collected and analysed in the laboratory. Indoor radon and thoron concentrations were found to be more than 1kBqm(-3) and 200Bqm(-3), respectively. Extremely high concentrations of soil-gas radon (>2000kBqm(-3)) and radon exhalation rates (1.5mBqm(-2)s(-1)) were observed. These results will be utilised to set up the methodology for a more systematic investigation.  相似文献   
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Environmental Science and Pollution Research - This paper discusses interactions between the generation, collection and recovery of used tyres while considering an indicator of their mass...  相似文献   
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