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1.
利用稳定同位素碳比率δ13C作为天然示踪物,对高位养殖池生态系统中人工饲料和天然饵料提供的能源物质对养殖凡纳滨对虾生长的贡献比率进行研究。结果表明:虾体的δ13C值受食物δ13C值的影响,由于其摄食饵料的δ13C值逐渐减小,虾体的δ13C值也逐渐降低,逐渐接近于最后人工饲料的δ13C值,试验虾体的δ13C值由养殖开始时的-19.52‰±0.09‰变为实验结束时的-21.74‰±0.17‰;对虾的食性在10d左右时发生转变,34d左右时人工饲料和浮游动物对虾体的能量贡献基本相同,养殖结束时对虾生长能量的97.29%±0.98%来源于人工饲料。 相似文献
2.
工频干扰相对高速采集系统内的信号频段极窄,时域内工频陷波需要很好的衰减特性,传统IIR、FIR等时域方法设计需要非常高的阶数,软硬件实现较为困难。以高采样率地震电磁辐射脉冲观测系统为例,结合系统核心处理器TMS320C6416的特点,选择频域滤波算法,并对此算法加以改进,使之能够实现信号的完美重构并满足系统的实时性要求,理论证明该算法原理简单、耗时少,能够有效抑制地震电磁脉冲工频干扰,仿真结果也验证了该算法的有效性。 相似文献
3.
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4.
《中国海洋湖沼学报》2016,(6)
This study examines whether a group of captive false killer whales(P seudorca crassidens) showed variations in the vocal rate around feeding times. The high level of motivation to express appetitive behaviors in captive animals may lead them to respond with changes of the behavioral activities during the time prior to food deliveries which are referred to as food anticipatory activity. False killer whales at Qingdao Polar Ocean World(Qingdao, China) showed signifi cant variations of the rates of both the total sounds and sound classes(whistles, clicks, and burst pulses) around feedings. Precisely, from the Transition interval that recorded the lowest vocalization rate(3.40 s/m/d), the whales increased their acoustic emissions upon trainers' arrival(13.08 s/m/d). The high rate was maintained or intensifi ed throughout the food delivery(25.12 s/m/d), and then reduced immediately after the animals were fed(9.91 s/m/d). These changes in the false killer whales sound production rates around feeding times supports the hypothesis of the presence of a food anticipatory vocal activity. Although sound rates may not give detailed information regarding referential aspects of the animal communication it might still shed light about the arousal levels of the individuals during different social or environmental conditions. Further experiments should be performed to assess if variations of the time of feeding routines may affect the vocal activity of cetaceans in captivity as well as their welfare. 相似文献
5.
This study examines whether a group of captive false killer whales (Pseudorca crassidens ) showed variations in the vocal rate around feeding times. The high level of motivation to express appetitive behaviors in captive animals may lead them to respond with changes of the behavioral activities during the time prior to food deliveries which are referred to as food anticipatory activity. False killer whales at Qingdao Polar Ocean World (Qingdao, China) showed significant variations of the rates of both the total sounds and sound classes (whistles, clicks, and burst pulses) around feedings. Precisely, from the Transition interval that recorded the lowest vocalization rate (3.40 s/m/d), the whales increased their acoustic emissions upon trainers’ arrival (13.08 s/m/d). The high rate was maintained or intensified throughout the food delivery (25.12 s/m/d), and then reduced immediately after the animals were fed (9.91 s/m/d). These changes in the false killer whales sound production rates around feeding times supports the hypothesis of the presence of a food anticipatory vocal activity. Although sound rates may not give detailed information regarding referential aspects of the animal communication it might still shed light about the arousal levels of the individuals during different social or environmental conditions. Further experiments should be performed to assess if variations of the time of feeding routines may affect the vocal activity of cetaceans in captivity as well as their welfare. 相似文献
6.
In nature, Apostichopus japonicus exhibits a behavioral characteristic of emerging at night and sheltering during the day. Hence, it was commonly believed that longer and darker light conditions are better for a population of A. japonicus. In aquaculture situations therefore, animals have commonly been cultured without lighting, especially during juvenile-hatching culture. However, how the length of darkness each day affects A. japonicus and what the mechanism is of behavioral response of A. japonicus to different photoperiods remain unclear, and are specifically addressed in this study. We applied nine photoperiod treatments (light:dark (LD) cycles at 0:24, 3:21, 6:18, 9:15, 12:12, 15:9, 18:6, 21:3, and 24:0 under 500 lx) to 60 individuals (29.73 ± 0.23 g) per treatment (with 3 replicates). The environmental conditions were set as: water temperature = 16.9 ± 0.3°C, dissolved oxygen>6.0 mg/L, ammonia<0.3 mg/L, pH = 7.8-8.2, and salinity = 30-32. Under experimental conditions of continuous darkness as well as continuous light, cyclic nocturnal activity patterns of A. japonicus (viz. the animals emerged and fed at night and sheltered during the day) were observed. However, they spent more and less time, respectively, moving and feeding under continuous darkness and continuous light, than those under a natural light cycle. Under photoperiods with 6-12 h of light, the animals showed one sheltering behavior transition and two emerging behavior transitions. These behavior transitions appeared to be governed by some internal physiological factors and induced by daily light variation. The behavior of the animals was significantly affected by different photoperiods, and the distribution rate (DR) of the animals emerging at "daytime" increased with lengthening "light time" (except for the LD 3:21 cycle). We also found that there was no significant difference in mean DR per day under LD cycles of 6:18, 9:15, 15:9, and 12:12. Mean DRs per day were significantly lower for these photoperiods, than for those under LD cycles of 0:24 and 3:21, and significantly higher than for those under LD cycles of 18:6, 21:3 and 24:0. These results imply that 6-15 h light per day were the similar photoperiods to natural sunlight. From the viewpoint of activity and feeding behaviors, these might be the optimal photoperiods for rearing A. japonicus. 相似文献
7.
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8.
用采集时钟方波信号加以分析的方法评估地震数据采集器的授时、守时服务精度、稳定性及系统特性。将具有时钟误差日志记录的数采的时间精度测试结果与日志记录相比较，二者完全一致；用时钟方波信号实测的数采经验传递函数与用厂家提供的滤波器系数并校正滤波器时间延迟计算的理论频率特性相符。实测结果显示，由于数采守时误差变化呈非线性，即使同一型号的不同数采间，其守时能力也可以差别很大；对于不同的数采及抽取滤波器，由于滤波延迟时间校正的参考点不一致，可导致数采记录数据的时间服务存在1个采样点左右的时间差，这对时间精度要求高的研究工作是不能接受的。 相似文献
9.
吉富罗非鱼最适生长水温研究 总被引：3，自引：0，他引：3
为研究不同养殖水温对吉富罗非鱼摄食和生长的影响,了解吉富罗非鱼的最适生长水温,实验设计28℃、30℃、32℃、34℃4个不同温度梯度,周期45 d。结果表明:不同水温环境下吉富罗非鱼表现出不同的生长特性,养殖在30℃水体中的罗非鱼生长速度明显高于其他温度组;水温对吉富罗非鱼的特定生长率、绝对增重率、饲料转化率、摄食率有显著影响(P<0.05),之间的相关关系可以用二次回归曲线来描述,特定生长率(SGR)与水温的关系式为rSGR=-19.255+1.3794T-0.0235T2,摄食率(FR)与水温的关系式为rFR=-22.175+1.5901T-0.026 6 T2,饲料转化率(FCR)与水温的关系式为rFCR=34.041-2.2256T+0.0382 T2;吉富罗非鱼的最适生长水温为29.3℃,最大摄食率的水温为29.9℃,最高食物转化率水温为29.1℃。 相似文献
10.
为了对双线偏振雷达的差分传播相移ΦDP进行滤波降噪处理,提高双线偏振雷达识别粒子、估测降水的能力。通过对C波段双线偏振雷达差分传播相移分别采用滑动平均、中值滤波、FIR滤波、卡尔曼滤波和小波分析5种不同方法地介绍,利用中国气象科学研究院灾害天气国家重点实验室移动式C波段双线偏振雷达(POLC)2013年外场试验观测资料,对比分析了经5种方法处理后的差分传播相移ΦDP径向数据,及其分别在降水估测中应用的效果。结果表明:采用FIR滤波方法、卡尔曼滤波方法和小波分析方法对ΦDP径向数据进行处理的效果比传统的滑动平均和中值滤波方法好;其中小波分析处理的ΦDP径向数据波动最小,再经过变距离法拟合的KDP数据的负值能够得到最有效地抑制,最后应用到R(KDP)降水估测中的精度最高。 相似文献
11.
高分辨率卫星影像图在震害快速预估中的应用 总被引：6，自引：2，他引：4
随着高分辨率卫星遥感技术的发展,遥感技术在地震灾害预估、评估和地震应急工作中发挥着越来越重要的作用,并成为震害评估和应急工作的重要发展方向之一。通过分析高分辨率遥感影像上建筑物的影像特征,设计了一种自动提取建筑物三维信息的模型;将提取出的建筑物三维信息,结合实验区人工调查的人口、经济数据．利用震害矩阵计算出不同类型建筑物在地震烈度场内的破坏等级和不同破坏等级建筑物的总面积,给出一定地震等级下的人员伤亡和经济损失的实际数据,建立了一套利用高分辨率卫星进行震害预估的技术流程。选取上海市宝山区为试验区．利用该技术进行了震害预估试验研究。预估结果具有较高的精度。 相似文献
12.
The exceptionally large individual growth variation has been previously recognized in several sea cucumber cohorts. However, there is a lack of information regarding the mechanism of such individual differences. In this study, the sea cucumber Apostichopus japonicus(Selenka)was reared individually in order to eliminate possible effects of social interaction, stocking density, etc. The results showed that there were substantial differences in growth among the sea cucumber individuals during the 100-day experiment. The special growth rate of the sea cucumber individuals differed by up to three folds(from 0. 40% to 1.01%), and the coefficient of variation in body weight increased from 12. 04% to 40. 51%. The final wet body weight, food intake and food conversion efficiency for each sea cucumber were generally positively correlated with their initial wet body weight(P<0. 05). Energy budget of the animals showed that the food energy spent on respiration was much greater(about four folds)but energy deposited for growth was much less for(initially)smaller than for larger A. Japonicus. The present result implies that there are obvious genetic differences among the sea cucumber individuals, largely accounting for the individual growth variation of the cohort sea cucumber. These results will provide some basic data for promoting selective breeding and farming of the sea cucumber. 相似文献
13.
Chlorella pyrenoidosa(Chlorophyceae) is widely cultured for production of health food and animal feed. In outdoors, mass cultivation of C. pyrenoidosa often suf fers from high temperature. A better understanding of the ef fects of high temperature on photosynthesis and photoprotection can help optimize the productivity of C. pyrenoidosa cultures. In this study, we investigated ef fect of high temperature(35, 38, or 41℃) on the balance between photosynthetic light absorption and energy utilization of C. pyrenoidosa. In contrast to 30℃, higher temperature of 35 or 38℃ did not inhibit the growth of C. pyrenoidosa. Treatment in 35℃ maintained the balance. Moreover, the PSI acceptor side in 38℃ was over-reduced and PSII reaction centers were over-excited under strong light, which destroyed the balance and generated active oxygen species(AOS). However, the activated antioxidant enzymes might remove completely the over-production of AOS, thereby protect C. pyrenoidosa cells from photodamage. It shows that this C. pyrenoidosa strain could tolerate as high as 38℃. Furthermore, treatment in 41℃ resulted in more lack of the balance than that in 38℃. However, the activities of antioxidant enzymes stopped increasing in 41℃, and were not strong enough to remove the excess AOS. Therefore, treatment in 41℃ could decrease the growth of C. pyrenoidosa. In addition, strong and longtime light exposure would cause serious photodamage to C. pyrenoidosa cells. 相似文献
14.
介绍一种特殊的CIC级联数字滤波器，它能对窄带信号进行滤波。通过抽点的方法能够有效地降低采样频率，而不影响有用信号。 同时介绍了运用SPTool图形化数字滤波器设计工具箱来设计凯泽窗FIR低通数字滤波器。 相似文献
15.
大珠母贝人工苗工厂化分组标粗；室内养殖５４ｄ，贝苗平均壳高从入池时６．６１ｍｍ增长至１３．０８ｍｍ，最大为１４．２５ｍｍ，平均成活率３１．９％，最高达４９．８％。试验结果初步表明：１．大珠母贝岸上室内工厂化养殖不但可行，而且也将是解决当前海上养成困境的一条出路；２．发现自然海区中也存在饥饿死亡现象及死亡潜伏期，反映出海上养殖高死亡率的复杂性；３．人工配合饲料的应用显著提高了贝苗的增长率和成活率，显示出广阔的商业价值。 相似文献
16.
《山地科学学报》2020,17(6):1294-1309
Perturbations caused by windstorms usually lead to the harvesting and clearcutting of fallen trees and wood debris, especially in the areas of managed forest ecosystems. Induced shifts in soils due to management practices play a crucial role in the restoration and maintaining of key ecosystem services.This paper focuses on topsoil chemical properties in relation to vegetation type(trees, shrubs and herbs)evolving at windstorm damaged(in 2004) areas with former Norway spruce(Picea abies) forests in the Tatra Mts. region(Slovakia). We assessed the content of topsoil organic matter fractions(extractives,holocellulose(HC) and lignin(Lig)), carbon in microbial biomass(C_(mic)), soil organic matter(SOM)and the content of elements N, C, H and S. The study plots represent different types of post-windthrow disturbance history/regime: wooden debris extraction(EXT), wooden debris not extracted(NEX), wooden debris extraction followed by wildfire(FIR), affected by the windstorm in 2014 with the subsequent wooden debris extraction(REX) and unaffected(REF). Our results revealed significant differences among sites in the content of dichloromethane extractives(EXT vs. REX and FIR), acetone extractives(NEX vs. EXT, FIR and REF), ethanol extractives(FIR vs. EXT, NEX and REF), water extractives(FIR vs. REX, NEX) and C_(mic)(EXT vs.NEX, FIR and REF). The topsoil of Vaccinium myrtillus and Picea abies showed a higher ratio of C/N, N/Lig, and Lig/HC compared to Rubus idaeus,Avenella flexuosa, Calamagrostis villosa, and Larix decidua. The content of N, C, H and S varied between topsoil with shrubs(Vaccinium myrtillus, Rubus idaeus) and grasses(Avenella flexuosa,Calamagrostis villosa). A positive correlation between soil organic matter(SOM) and polar extractives(r=0.81) and a negative correlation between SOM and HC(r=-0.83) was revealed. The carbon content in microbial biomass(C_(mic)) is positively correlated with acid soluble lignin(ASL)(r=0.85). We also identified a strong correlation between Klason lignin(KL) and the Lig/HC ratio(r=0.97). 相似文献
17.
Land animals as well as all organisms in ocean synthesize sulfated polysaccharides. Fungi split from animals about 1.5 billion years ago. As fungi make the evolutionary journey from ocean to land, the biggest changes in their living environment may be a sharp decrease in salt concentration. It is established that sulfated polysaccharides interact with hundreds of signaling molecules and facilitate many signaling transduction pathways, including fibroblast growth factor(FGF) and FGF receptor signaling pathway. The disappearance of sulfated polysaccharides in fungi and plants on land might indicate that polysaccharides without sulfation might be sufficient in facilitating protein ligand/receptor interactions in low salinity land. Recently, it was reported that plants on land start to synthesize sulfated polysaccharides in high salt environment, suggesting that fungi might be able to do the same when exposed in such environment. Interestingly, Cordyceps, a fungus habituating inside caterpillar body, is the most valued traditional Chinese Medicine. One of the important pharmaceutical active ingredients in Cordyceps is polysaccharides. Therefore, we hypothesize that the salty environment inside caterpillar body might allow the fungi to synthesize sulfated polysaccharides. To test the hypothesis, we isolated polysaccharides from both lava and sporophore of wild Cordyceps and also from Cordyceps militaris cultured without or with added salts. We then measured the polysaccharide activity using a FGF2/FGFR1 c signaling-dependent Ba F3 cell proliferation assay and found that polysaccharides isolated from wild Cordyceps activated FGF2/FGFR signaling, indicating that the polysaccharides synthesized by wild Cordyceps are indeed different from those by the cultured mycelium. 相似文献
18.
There is substantial individual variation in the growth rates of sea cucumber Apostiehopus japonicus individuals. This necessitates additional work to grade the seed stock and lengthens the production period. We evaluated the influence of three culture methods （free-mixed, isolated-mixed, isolated-alone） on individual variation in growth and assessed the relationship between feeding, energy conversion efficiency, and individual growth variation in individually cultured sea cucumbers. Of the different culture methods, animals grew best when reared in the isolated-mixed treatment （i.e., size classes were held separately）, though there was no difference in individual variation in growth between rearing treatment groups. The individual variation in growth was primarily attributed to genetic factors. The difference in food conversion efficiency caused by genetic differences among individuals was thought to be the origin of the variance. The level of individual growth variation may be altered by interactions among individuals and environmental heterogeneity. Our results suggest that, in addition to traditional seed grading, design of a new kind of substrate that changes the spatial distribution of sea cucumbers would effectively enhance growth and reduce individual variation in growth of sea cucumbers in culture. 相似文献
19.
1 Introduction TheAntarcticcontinentissurroundedbyPacificOcean,theAtlanticOceanandthe IndianOcean,itistheisolatedcontinentfarthestfromthemankind.ItsSpecialgeography andclimateenvironmentmakethemankindverydifficulttobeclosetoit,whichlimits mankind'sinvestigationofitandstudytoagreatextent.Restrictioncausedofthegeograph icalenvironmentandtheclimatecanbebrokentoagreatextentwiththeaidofthemodern remotesensingtechnology,itdemonstratesincomparablesuperioritythatremotesensing technologyisusedin… 相似文献
20.
This paper briefly reviews the cause of the striping and then develops a tapered (Chebwin & Kaiser) window finite impulse response (FIR) filter and a constrained least squares FIR filter by reason of the striping of ASTER satellite data . Both filters minimize the stripes in the visible data and simultaneously minimize any distortion in the filtered data. Finally, the results obtained by using these new filtering methods are quantitatively compared with those produced by other destriping methods. 相似文献