排序方式： 共有19条查询结果，搜索用时 64 毫秒
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Michael K. Musyl Richard W. Brill Christofer H. Boggs Daniel S. Curran Thomas K. Kazama Michael P. Seki 《Fisheries Oceanography》2003,12(3):152-169
To learn more about the movement patterns of bigeye tuna (Thunnus obesus), we deployed archival tags on 87 fish ranging in fork length from 50 to 154 cm. Thirteen fish were recaptured, from which 11 archival tags were returned, representing in aggregate 943 days‐at‐liberty. We successfully retrieved data from 10 tags, representing 474 days in aggregate. The largest fish recaptured was 44.5 kg [131 cm fork length (FL)] and the smallest 2.8 kg (52 cm). The deepest descent recorded was 817 m, the coldest temperature visited 4.7°C, and minimum oxygen level reached ～1 mL L?1. Fish spent little time at depths where water temperatures were below 7°C and oxygen levels less than ～2 mL L?1. Five fish were recaptured near the offshore weather buoy where they were tagged. Based on vertical movement patterns, it appeared that all stayed immediately associated with the buoy for up to 34 days. During this time they remained primarily in the uniform temperature surface layer (i.e. above 100 m). In contrast, fish not associated with a floating object showed the W‐shaped vertical movement patterns during the day characteristic of bigeye tuna (i.e. descending to ～300–500 m and then returning regularly to the surface layer). Four fish were tagged and subsequently recaptured near Cross Seamount up to 76 days later. These fish exhibited vertical movement patterns similar to, but less regular than, those of fish not associated with any structure. Bigeye tuna appear to follow the diel vertical movements of the deep sound scattering layer (SSL) organisms and thus to exploit them effectively as a prey resource. Average night‐time depth was correlated with lunar illumination, a behaviour which mimics movements of the SSL. 相似文献
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Viscoelasticity describes the ability of a material to possess both elasticity and viscosity. Viscoelastic materials, such as rubbers, possess a limited operational temperature range (for example, for silicone rubber it is -55° to 300°C), above which the material breaks down and below which the material undergoes a glass transition and hardens. We created a viscoelastic material composed from a random network of long interconnected carbon nanotubes that exhibited an operational temperature range from -196° to 1000°C. The storage and loss moduli, frequency stability, reversible deformation level, and fatigue resistance were invariant from -140° to 600°C. We interpret that the thermal stability stems from energy dissipation through the zipping and unzipping of carbon nanotubes at contacts. 相似文献
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Wilawan Khanitchaidecha Maneesha Shakya Kamei Tatsuru Futaba Kazama 《Water, air, and soil pollution》2012,223(7):3939-3953
To provide good quality of drinking water, a biological system to remove ammonium-nitrogen (NH4-N) from groundwater was studied in this research. The NH4-N removal system consists of two attached growth reactors: one for nitrification and the other for hydrogenotrophic denitrification (H. denitrification). The nitrification reactor, fed by the NH4-N contained water, could remove NH4-N without any need of aeration. The nitrification efficiency was increased by reactor length; the highest efficiency of 92?% was achieved at the longest reactor of 100?cm. A high Fe in groundwater affected the reactor performance by decreasing the efficiency, while a low inorganic carbon (IC) had no effects. Despite of good efficiency in terms of NH4-N removal, the nitrification reactor increased the concentration of NO3-N in its effluent. To treat the NO3-N, a H. denitrification reactor was set up after the nitrification reactor. Efficiency of the H. denitrification reactor was enhanced by increasing H2 flow rates. The efficiencies were 3, 27, and 90?% for 30, 50, and 70?mL/min of H2 flow rates, respectively. It was also found that the NO3-N contained water (water from the nitrification reactor) had to supply IC (i.e., NaHCO3 or CO2) for efficient H. denitrification; however, an on-site reactor showed that it can be achieved even without IC addition. The treated water contained low NH4-N and NO3-N of <1.5 and <11.3?mg/L, respectively, which comply with drinking water standards. The good performance of the reactors in terms of high efficiency, no aeration need, and low H2 supply indicated appropriateness of the system for groundwater treatment. 相似文献
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Isolation and characterization of a phenolic antioxidant from the Pacific oyster (Crassostrea gigas)
Watanabe M Fuda H Jin S Sakurai T Ohkawa F Hui SP Takeda S Watanabe T Koike T Chiba H 《Journal of agricultural and food chemistry》2012,60(3):830-835
Using an oxygen radical absorbance capacity (ORAC) assay, antioxidant activity was detected in the ethanol extract of the Pacific oyster, which was purified by sequential extraction with organic solvents. The ethyl acetate fraction showed the strongest antioxidant activity and was further purified, yielding a single compound [as assessed by thin-layer chromatography (TLC) and reverse-phase high-performance liquid chromatography (HPLC)]. This compound was identified as 3,5-dihydroxy-4-methoxybenzyl alcohol on the basis of (1)H and (13)C nuclear magnetic resonance (NMR), heteronuclear multiple-bond correlation (HMBC), and electrospray ionization-mass spectrometry (ESI-MS) spectral analyses, a conclusion that was confirmed by chemical synthesis. The concentration of the compound was 6.7 mg/100 g of whole oyster meat wet weight. This amphiphilic antioxidant retarded the copper-mediated oxidation of low-density lipoproteins (LDLs) and the generation of thiobarbituric acid reactive substances. Furthermore, the compound showed substantial antioxidant activity using the ORAC and 2,2-diphenyl-1-picrylhydrazyl (DPPH) assays compared to natural antioxidants. Although the same compound was previously found in brown algae, its presence in other organisms and antioxidant activity are reported here for the first time. 相似文献
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dos Santos Adão Felipe da Silva Rouverson Pereira Zerbato Cristiano de Menezes Patricia Candida Kazama Elizabeth Haruna Paixão Carla Segato Strini Voltarelli Murilo Aparecido 《Precision Agriculture》2019,20(4):840-856
Among the main techniques employed in precision agriculture, yield mapping and automatic guidance of agricultural machines are the best-known to farmers. The objective of this study was to evaluate, using statistical process control tools, the quality of automatic guidance using satellite signals, to reduce positioning errors and losses in peanut digging. The treatments consisted of the use of manual (operator guidance) and automatic (autopilot) guidance with RTX satellite signals in sowing and digging operations. The quality of the operation was evaluated after collection of 30 points spaced at 100 m for each quality indicator, which are the losses and the errors of alignment of the mechanised sets in sowing and digging operations. From the perspective of statistical control, manual guidance was shown to be compromised for the quality indicators of digging losses. Despite the instability in the sowing and digging operations, the use of automatic guidance proved to be accurate. The use of automatic guidance increases the precision and reduces overlaps (<?38 mm, as stipulated by the supplier) for sowing and digging. The manual sowing mean error between overlaps was stable; however, it did not remain constant over time.
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Kazama Elizabeth Haruna da Silva Rouverson Pereira Tavares Tiago de Oliveira Correa Lígia Negri de Lima Estevam Francisca Nivanda Nicolau Francisca Edcarla de Araújo Maldonado Júnior Walter 《Precision Agriculture》2021,22(3):711-733
Precision Agriculture - The non-uniformity of coffee fruit maturation is an intrinsic plant condition that is not favorable for the beverage quality. This could be overcome by using the precision... 相似文献
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Watarai M Kim S Yamamoto J Miyahara K Kazama M Matsuoka S Chimura S Suzuki H 《The Journal of veterinary medical science / the Japanese Society of Veterinary Science》2007,69(5):477-480
Brucella canis is the causative agent of canine brucellosis and facultative intracellular pathogen. The diagnosis of canine brucellosis is based on bacteriological examination and serological methods including agglutination and gel diffusion tests. In this study, crude antigens were extracted from B. canis using hot saline, coated on to latex beads and their usefulness in the serological diagnosis of canine brucellosis was examined. Mixing the antigen coated latex beads with the sera of dogs infected with B. canis produced clear agglutination, but this was not so for B. canis free dog sera. N-terminal amino acid sequence analysis of the crude hot saline extracts, showed that they contained copper-zinc superoxide dismutase, ribose ABC transporter and hypothetical protein of Brucella as antigens. A serological survey of canine serum samples conducted by means of an agglutination test using the antigen coated latex beads, showed that this method was more specific than the tube agglutination test using whole bacterial cell antigens. Although these results suggest that our method in which crude hot saline extracted antigens are coated on to latex beads would be useful in the serological diagnosis of canine brucellosis, we need further investigation using more serum samples to confirm the usefulness of our method. 相似文献
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Assessment of Deep Groundwater Quality in Kathmandu Valley Using Multivariate Statistical Techniques 总被引：2，自引：0，他引：2
Saroj Kumar Chapagain Vishnu P. Pandey Sangam Shrestha Takashi Nakamura Futaba Kazama 《Water, air, and soil pollution》2010,210(1-4):277-288
This study was carried out to assess the overall water quality and identify major variables affecting the deep groundwater quality in Kathmandu Valley, Nepal. Forty-two deep wells were sampled during premonsoon and monsoon seasons in 2007 and analyzed for the major physicochemical variables. The water quality variables such as NH 4 + -N, Fe, Pb, As, and Cd at most of the sampling locations exceeded the World Health Organization guideline levels for drinking water. Multivariate statistical techniques such as factor analysis and cluster analysis were applied to identify the major factors (variables) corresponding to the different source of variation in deep groundwater quality. Factor analysis indentified six major factors explaining 74.77% of the total variance in water quality; and the major variations are related with the degree of groundwater mineralization, decomposition of organic matter, and reduction of groundwater environment. The water quality of deep groundwater is influenced by the natural hydrogeochemical environment. The wells are broadly divided into two major groups based on the similar groundwater characteristics using cluster analysis. Results show that water quality of deep groundwater does not vary significantly as a function of season. 相似文献