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171.
Effects of water temperature (17, 21, 25, 30 and 35℃) and body size (14.75-281.41 g initial body weight) on food consumption, growth, feed conversion, and dry matter content in orange-spotted grouper fed to satiation were investigated. The combined effect of temperature (T, ℃) and body weight (W, g) on maximum food consumption (Cmax, g/day) was described as: InCmax=-7.411+0.828 InW+0.317T4).004 7T2, and the optimum feeding temperature was 33.9℃. The combined effect of temperature and body weight on growth (G) was described as: lnG=-4.461-0.2081nW+0.394T-0.006 3T^2. The optimum growth temperature was 31.4℃, whereas overall growth rates were high at 25, 30 and 35 ℃. Feed conversion efficiencies (FCE, %), increasing first and then decreasing with increasing temperature, averaged from 1.8 to 2.1 in terms of dry weight of food fish. The optimum temperature for FCE tended to be lower than that for growth or feeding. Dry matter content increased with both increasing water temperature (17, 25, 30 and 35℃) and body weight, and the combined effect of temperature and body weight on dry matter content (DM, %) was described as: lnDM =3.232+0.01 4 lnW-0.004 4T+0.001 2TInW. 相似文献
172.
Tamarix nabkha is one of the most widespread nabkhas,distributing in the arid region of China.Based on the observations outdoors and the simulation experiments in laboratories,analysis in this paper refers to the biological geomorphologic features and growth process of Tamarix nabkhas in the middle and lower reaches of the Hotan River,Xin- jiang.And the results indicate that the ecological type of Tamarix in the study area is a kind of Tugaic soil habitat based on the deep soil of the Populus Diversifolia f... 相似文献
173.
Vishal Chandr Jaunky 《Natural Resources Research》2012,21(2):265-278
The article attempts to test the aluminum consumption–economic growth nexus for 20 rich economies for the period 1970–2009.
Various panel data unit root and cointegration tests are applied. The series are found to be integrated of order one and cointegrated,
especially after controlling for cross-sectional dependence. Moreover, the Blundell–Bond system generalized methods-of-moments
is employed to conduct a panel causality test in a vector error-correction mechanism setting. Unidirectional causality running
from aluminum consumption to real GDP is uncovered in the short-run, while real GDP is found to Granger-cause aluminum consumption
in the long-run. Moreover, a 1% increase in real GDP generates an increase of 0.44% in aluminum consumption in the long-run
for the whole panel. 相似文献
174.
Jamal Asfahani 《Acta Geophysica》2017,65(4):765-775
An alternative approach using nuclear neutron-porosity and electrical resistivity well logging of long (64 inch) and short (16 inch) normal techniques is proposed to estimate the porosity and the hydraulic conductivity (K) of the basaltic aquifers in Southern Syria. This method is applied on the available logs of Kodana well in Southern Syria. It has been found that the obtained K value by applying this technique seems to be reasonable and comparable with the hydraulic conductivity value of 3.09 m/day obtained by the pumping test carried out at Kodana well. The proposed alternative well logging methodology seems as promising and could be practiced in the basaltic environments for the estimation of hydraulic conductivity parameter. However, more detailed researches are still required to make this proposed technique very performed in basaltic environments. 相似文献
175.
Developing approaches to automate the analysis of the massive amounts of data sent back from the Moon will generate significant benefits for the field of lunar geomorphology. In this paper, we outline an automated method for mapping lunar landforms that is based on digital terrain analysis. An iterative self-organizing (ISO) cluster unsupervised classification enables the automatic mapping of landforms via a series of input raster bands that utilize six geomorphometric parameters. These parameters divide landforms into a number of spatially extended, topographically homogeneous segments that exhibit similar terrain attributes and neighborhood properties. To illustrate the applicability of our approach, we apply it to three representative test sites on the Moon, automatically presenting our results as a thematic landform map. We also quantitatively evaluated this approach using a series of confusion matrices, achieving overall accuracies as high as 83.34% and Kappa coefficients (K) as high as 0.77. An immediate version of our algorithm can also be applied for automatically mapping large-scale lunar landforms and for the quantitative comparison of lunar surface morphologies. 相似文献
176.
Modern physical geography in China grew from Chinese traditional geography and has been profoundly influenced by the geographical disciplines of Euro-America and Russia. Since the 1950s, integrated studies of physical geography in China have made remarkable progress in the fields of comprehensive physical geographical regionalization, land studies, landscape ecology, and land surface geographical processes. During the past few decades, under the background of global change and rapid socio-economic transformation, a series of environmental and resources problems have boomed in China. To solve these problems and promote the development of integrated studies of physical geography, the following issues were proposed as research priorities: (1) coupling of land surface patterns and processes; (2) integrated research on regional responses and adaptation to global change; (3) analysis of human dimensions of the earth system; (4) ecosystem service research from a geographical perspective; (5) integration of multi-source data and model development; (6) integrated studies on unique geographical units; and (7) important global issues and relevant international programs. 相似文献
177.
Fine-resolution simulation of surface current and sea ice in the Arctic Mediterranean Seas 总被引:1,自引:0,他引:1
A fine-resolution model is developed for ocean circulation simulation in the National Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics (LASG), Chinese Academy of Sciences, and is applied to simulate surface current and sea ice variations in the Arctic Mediterranean Seas. A dynamic sea ice model in elastic-viscous-plastic rheology and a thermodynamic sea ice model are employed. A 200-year simulation is performed and a dimatological average of a 10-year period (141st-150th) is presented with focus on sea ice concentration and surface current variations in the Arctic Mediterranean Seas. The model is able to simulate well the East Greenland Current, Beaufort Gyre and the Transpolar Drift, but the simulated West Spitsbergen Current is small and weak. In the March climatology, the sea ice coverage can be simulated well except for a bit more ice in east of Spitsbergen Island. The result is also good for the September scenario except for less ice concentration east of Greenland and greater ice concentration near the ice margin. The extra ice east of Spitsbergen Island is caused by sea ice current convergence forced by atmospheric wind stress. 相似文献
178.
Lei Xing Huaishan Liu Xilai Zheng Xueqin Liu Jin Zhang Linfei Wang Zhihui Zou Yiming Xu 《中国海洋大学学报(英文版)》2016,15(5):815-824
Air guns are important sources for marine seismic exploration. Far-field wavelet of air gun arrays, as a necessary parameter for pre-stack processing and source models, plays an important role during marine seismic data processing and interpretation. When an air gun fires, it generates a series of air bubbles. Similar to onshore seismic exploration, the water forms a plastic fluid near the bubble; the farther the air gun is located from the measurement, the more steady and more accurately represented the wavelet will be. In practice, hydrophones should be placed more than 100 m from the air gun; however, traditional seismic cables cannot meet this requirement. On the other hand, vertical cables provide a viable solution to this problem. This study uses a vertical cable to receive wavelets from 38 air guns and data are collected offshore Southeast Qiong, where the water depth is over 1000 m. In this study, the wavelets measured using this technique coincide very well with the simulated wavelets and can therefore represent the real shape of the wavelets. This experiment fills a technology gap in China. 相似文献
179.
Neolithic culture series in the Yishu River Basin developed in the order of Beixin culture-Dawenkou culture-Longshan culture-Yueshi culture. During the early and middle stage of Longshan culture (4600-4300 cal. yr BP), the climate in the Yishu River Basin was warm and wet. Paddy-oriented agriculture planted paddy was very developed. The society was flourishing with great amount of archaeological sites. The cooling starting in 4200 cal. yr BP made the paddies shortfall in output or even no seeds were gathered. This situation intensified the discrepancy between population and resource. The scarcity in natural resource led to substantial decrease in population and subsequent drop in archaeological sites. About 4000 cal. yr BP Longshan culture was displaced by Yueshi culture which was relatively un- derdeveloped, simple and unsophisticated. 相似文献
180.
Wei Ye Qu Chen Lidong Zhu Fengquan Li Tianyang Wang Longjuan Cheng Yunxia Zhang 《Journal of Paleolimnology》2018,59(2):263-278
A long-standing controversy exists concerning the spatial and temporal characteristics of Holocene climate change in China. Zhejiang is located in the southeast of China, where the East Asian monsoon dominates the climate and a Neolithic culture flourished. In recent years, geographers have debated the climatic conditions existing at the time of the Neolithic cultures. This study reconstructed the sedimentary environment between 11.30 and 4.17 cal ka BP based on a multi-proxy analysis of a 14.3 meter sediment core, drilled in Beihuqiao, Zhejiang Province, China. The results show: (1) The climate was getting warm between 11.50 and 8.77 cal ka BP. Grain size became finer from the bottom to the top layer, accompanied by an increase in the chemical index of alteration (CIA), Mg/Sr ratio, the percentage of clay, pollen concentrations, and a decrease in SiO2/Al2O3 ratio, and the value of bases–alumina (ba), as well as other trace elements. (2) Between 8.77 and 7.99 cal ka BP, the sediment is composed of gray-yellow and gray silt. The percentage of CaO and the ratio of CaO + Na2O + K2O to Al2O3 is much higher. The pollen concentration sharply decreases. The climate was cold and dry in the early stages of this period, but became relatively warmer and wetter in the later stages. (3) The Holocene Climatic Optimum occurred at 7.99–5.68 cal ka BP. Higher contents of clay, total Fe2O3, Al2O3, CIA, the chemical proxy of alteration, pollen concentration, evergreen pollens, and high values of Mg/Sr are observed at this stage, coinciding with a lower SiO2/Al2O3 value, (CaO + Na2O + K2O)/Al2O3 ratio, and an obvious reduction in silt/clay, and SiO2 and CaO concentrations. (4) During the period 5.68–4.17 cal ka BP, the temperature in the study area declined in a stepwise fashion. The grain size became finer, and the Mg/Sr ratio decreased gradually. 相似文献