396 research outputs found
A visual analysis of the usage efficiency of library books
The monographic collections in academic libraries have undergone a period of tremendous growth in volume, in subject diversity, and in formats during the recent several decades. Readers may find it difficult to prioritize which book(s) should be borrowed for a specific purpose. The log data of book loan record may serve as a visible indicator for the more sought-after books by the readers. This paper describes our experimental efforts in works in a university library setting. The visual analysis is thought to provide an effective way to extract the book usage information, which may yield new insights into a host of other related technical as well as user behavior issues. Initial experiment has demonstrated that the proposed approach as articulated in this article can actually benefit end-users as well as library collection development personnel in their endeavor of book selections with effective measure.</p
Buenas prácticas de transferencia del conocimiento en la Universidad de Córdoba
El proyecto demuestra la importancia y la necesidad de alcanzar la sostenibilidad económica y social, junto a la ambiental, en el sector del olivar. Para ello, propone una serie de actuaciones basadas en la mecanización y recolección del olivar y otros frutales; la agricultura de conservación y la de precisión; la prevención de los riesgos laborales en el sector; y la mejora de la maquinaria de distribución de agroquímicos. Todo ello para generar conocimiento e innovación de carácter tecnológico con el objetivo de transferir los avances a las empresas y los beneficios de su aplicación
Influence of outbreak of macroalgal blooms on phosphorus release from the sediments in Swan Lake Wetland, China
Macroalgal blooms have occurred worldwide frequently in coastal areas in recent decades, which dramatically modify phosphorus (P) cycle in water column and the sediments. Rongcheng Swan Lake Wetland, a coastal wetland in China, is suffering from extensive macroalgal blooms. In order to verify the influence of macroalgal growth on sediment P release, the sediments and filamentous Chaetomorpha spp. were incubated in the laboratory to investigate the changes of water quality parameters, P levels in overlying water, and sediments during the growth period. In addition, algal biomass and tissue P concentration were determined. In general, Chaetomorpha biomasses were much higher in high P treatments than in low P treatments. Compared with algae+low P water treatment, the addition of sediments increased the algal growth rate and P accumulation amount. During the algal growth, water pH increased greatly, which showed significant correlation with algal biomass in treatments with high P (P<0.05). P fractions in the sediments showed that Fe/Al-P and organic P concentrations declined during the algal growth, and great changes were observed in algae+low P water+sediment treatment for both. As a whole, the sediments can supply P for Chaetomorpha growth when water P level was low, and the probable mechanism was the release of Fe/Al-P at high pH condition induced by intensive Chaetomorpha blooms.Macroalgal blooms have occurred worldwide frequently in coastal areas in recent decades, which dramatically modify phosphorus (P) cycle in water column and the sediments. Rongcheng Swan Lake Wetland, a coastal wetland in China, is suffering from extensive macroalgal blooms. In order to verify the influence of macroalgal growth on sediment P release, the sediments and filamentous Chaetomorpha spp. were incubated in the laboratory to investigate the changes of water quality parameters, P levels in overlying water, and sediments during the growth period. In addition, algal biomass and tissue P concentration were determined. In general, Chaetomorpha biomasses were much higher in high P treatments than in low P treatments. Compared with algae+low P water treatment, the addition of sediments increased the algal growth rate and P accumulation amount. During the algal growth, water pH increased greatly, which showed significant correlation with algal biomass in treatments with high P (P<0.05). P fractions in the sediments showed that Fe/Al-P and organic P concentrations declined during the algal growth, and great changes were observed in algae+low P water+sediment treatment for both. As a whole, the sediments can supply P for Chaetomorpha growth when water P level was low, and the probable mechanism was the release of Fe/Al-P at high pH condition induced by intensive Chaetomorpha blooms
Soil-water interacting use patterns driven by Ziziphus jujuba on the Chenier Island in the Yellow River Delta, China
The determination of water use patterns of plants in a coastal ecosystem is critical to our understanding of local eco-hydrological processes and predicting trends in ecological succession under the background of global climate change. The water use patterns of Ziziphus jujuba, the dominant species on the Chenier Island in the Yellow River Delta, were examined following summer rainfall events. Stable oxygen isotope analysis was employed to analyze the effects of rainfall on the stable isotopic composition in potential water sources in Z. jujuba. The IsoSource model was used to estimate the contributions of potential water sources for xylem water in Z. jujuba. The results showed heavy rainfall could recharge both soil and groundwater but contributed little to the O-18 values in deep soil water (60-100cm) and groundwater. Light rainfall had an effect only on surface soil water (0-40cm). Z. jujuba mainly absorbed deep soil water on non-rainy days. Rainwater became the predominant water source for Z. jujuba during and immediately after heavy rainfall. Switching the plant's main water source between deep soil water and rainwater provided Z. jujuba with a competitive advantage and improved the water use efficiency of Z. jujuba in this coastal ecosystem
Web users' language utilization behaviors in China
The paper focuses on the habits of China Web users' language utilization behaviors in accessing the Web. It also seeks to make a general study on the basic nature of language phenomenon with regard to digital accessing. A questionnaire survey was formulated and distributed online for these research purposes. There were 1,267 responses collected. The data were analyzed with descriptive statistics, Chi-square testing and contingency table analyses. Results revealed the following findings. Tagging has already played an important role in Web2.0 communication for China's Web users. China users rely greatly on all kinds of taxonomies in browsing and have also an awareness of them in effective searching. These imply that the classified languages in digital environment may aid Chinese Web users in a more satisfying manner. Highly subject-specific words, especially those from authorized tools, yielded better results in searching. Chinese users have high recognition for related terms. As to the demographic aspect, there is little difference between different genders in the utilization of information retrieval languages. Age may constitute a variable element to a certain degree. Educational background has a complex effect on language utilizations in searching. These research findings characterize China Web users' behaviors in digital information accessing. They also can be potentially valuable for the modeling and further refinement of digital accessing services.</p
Effects of cultivation years on effective constituent content of Fritillaria pallidiflora Schernk
Fritillaria pallidiflora Schrenk has been treasured in traditional classic medicine as an antitussive, antiasthmatic and expectorant for hundreds of years. With gradually decreasing wild F. pallidiflora resources, the herb can no longer satisfy the demand. Artificial cultivation is one of the most effective ways to solve the contradiction between supply and demand in the medicinal material market. During the growth of Rhizomes medicinal plants, root biomass and active ingredient content showed dynamic accumulated variation with increasing cultivation years. Up to now, hardly any attempts have been made to investigate the relationship between quality and cultivation years of F. pallidiflora. Therefore, in this paper, we determined the optimum harvesting time by comparing biomass and biological characteristics of F. pallidiflora at different cultivation times. High-performance liquid chromatography with evaporative light scattering detection and phenol-sulfuric acid visible spectrophotometry was performed to determine imperialine and polysaccharide content of F. pallidiflora bulbs. From year 1 to 6 of cultivation, we observed an upward trend in plant height, diameter and dry weight of F. pallidiflora, while water content decreased. Plant height and dry weight increased remarkably during the fourth year of cultivation. The content of imperialine and polysaccharide of F. pallidiflora bulbs, on the other hand, showed an upward trend from year 1 to 3, after which it decreased from year 3 to 6. By comparing plant growth, biomass development and the accumulation of imperialine and polysaccharide, the best harvesting time of F. pallidiflora was determined to be after 4 years of cultivation. Our results showed that it is possible to establish a safe, effective, stable and controllable production process, which could play an important role in achieving sustainable utilization of F. pallidiflora resources.Fritillaria pallidiflora Schrenk has been treasured in traditional classic medicine as an antitussive, antiasthmatic and expectorant for hundreds of years. With gradually decreasing wild F. pallidiflora resources, the herb can no longer satisfy the demand. Artificial cultivation is one of the most effective ways to solve the contradiction between supply and demand in the medicinal material market. During the growth of Rhizomes medicinal plants, root biomass and active ingredient content showed dynamic accumulated variation with increasing cultivation years. Up to now, hardly any attempts have been made to investigate the relationship between quality and cultivation years of F. pallidiflora. Therefore, in this paper, we determined the optimum harvesting time by comparing biomass and biological characteristics of F. pallidiflora at different cultivation times. High-performance liquid chromatography with evaporative light scattering detection and phenol-sulfuric acid visible spectrophotometry was performed to determine imperialine and polysaccharide content of F. pallidiflora bulbs. From year 1 to 6 of cultivation, we observed an upward trend in plant height, diameter and dry weight of F. pallidiflora, while water content decreased. Plant height and dry weight increased remarkably during the fourth year of cultivation. The content of imperialine and polysaccharide of F. pallidiflora bulbs, on the other hand, showed an upward trend from year 1 to 3, after which it decreased from year 3 to 6. By comparing plant growth, biomass development and the accumulation of imperialine and polysaccharide, the best harvesting time of F. pallidiflora was determined to be after 4 years of cultivation. Our results showed that it is possible to establish a safe, effective, stable and controllable production process, which could play an important role in achieving sustainable utilization of F. pallidiflora resources
Photosynthetic characterization of three dominant plant species in the saline-alkaline soil of the Yellow River Delta, China
The diurnal variations of photosynthesis of three dominant species, including Glycine soja, Phragmites australis, and Cynanchum chinensis, in the Yellow River Delta in China have been studied under the same natural conditions using a Li-6400 portable photosynthesis system. The results showed that the curves of diurnal variations of net photosynthetic rate (P-N) of the three plants were different. The diurnal variation of P-N on C. chinensis was a midday depression pattern and had two peaks. However, P-N of G. soja and P. australis showed single-peak curves. The transpiration rate (E) of G. soja was significantly higher than that of P. australis and C. chinensis, both showed single-peak curves. In general, the diurnal course of stomatal conductance (g(s)) followed the same pattern of P-N. A similar diurnal pattern of intercellular CO2 concentration (C-i), vapor pressure deficit (VPD), and water use efficiency (WUE) was observed among different species. VPD showed single-peak curves, while WUE was characterized by double-peak curves, which was contrary to C-i. Linear correlations among photosynthetic variables and key environmental factors indicate high positive correlations between P-N and E, P-N and photosynthetic active radiation, P-N and leaf temperature (T-leaf), P-N and VPD, and between P-N and g(s) except C. chinensis. Negative correlations among P-N and relative humidity, P-N and C-i were found. The irradiance response curves derived from the leaves were substantially affected by different species. C. chinensis showed highest apparent quantum efficiency, followed by P. australis and G. soja, while apparent dark respiration (R-d), convexity (k), light saturation point, and maximum gross CO2 assimilation rate (P-max) of G. soja were higher than those of P. australis and C. chinensis. The irradiance response curve of P-N and WUE of different plant species followed the same order: G. soja>C. chinensis>P. australis. They were both higher than most of other species. It was concluded that plant species adapting to the saline-alkaline habitat showed higher photosynthesis. In addition, G. soja is also effective to improve saline-alkaline soil quality
Developing and sustainably utilize the coastal mudflat areas in China
Coastalmudflat areas are regarded as the important reserve land resource in China. Rational exploitation and development of the mudflat areas can relieve the stress of inadequate land resources. Probing into the developing models of resource exploitation of coastal tidal mudflats is one of the important components of achieving the sustainable development in the coastal areas. Therefore, the development history of coastal mudflats after 1950s in China is briefly introduced in this paper. Then, the status in quo of the modes of development and utilization of coastal mudflat in China the paper is reviewed with a special attention payed to the agricultural use of coastal resource, especially halophytes and improved salt-tolerant varieties planting, agricultural dyke pond and coastal saline-alkali soil remediation. Based on related research frontier, sustainable developmental prospects of these coastal areas are presented as well. (C) 2016 Published by Elsevier B.V
The research on nutrients release during the decomposition of Chaetomorpha sp.
通过室内模拟,研究了不同环境条件下绿潮硬毛藻的分解速率,以及死亡藻体内营养盐的释放规律,以阐明硬毛藻大量衰亡对天鹅湖水质的潜在影响。结果显示,温度对硬毛藻分解速率的影响显著(P沉积物>营养盐水平;N释放为:沉积物>温度>营养盐水平。高温条件下,死亡藻..
Water isotope technology application for sustainable eco-environmental construction: Effects of landscape characteristics on water yield in the alpine headwater catchments of Tibetan Plateau for sustainable eco-environmental construction
Topography-climate-vegetation-runoff relationships are important issues in hydrological studies. In this paper, based on analyzing water isotope characteristics of river water, the influence of these variables on the relative contribution of rain to river water was investigated during one rain event in the Heishui Valley of the upper Yangtze River in China. During one rain event on August 19, 2005, a total number of 182 river water samples were collected at 13 sampling sites located along the principal river course and its tributaries. The analysis of water isotopes in the principal river course and its tributaries showed that new rain water and secondary evaporation precipitation caused great variation in values of delta D and high d-excess increased with altitude. Based on calculations of two-component hydrograph separation using delta O-18, the results showed that the biggest relative contribution of new rain to river water (43%) was found in tributary B, while the smallest contribution (less than 5%) was found in tributary I. According to stepwise linear regression analysis, topography (elevation and slope) was the most important factor affecting the contributions of new rain to river water. When only vegetation variables were considered in the regression model, alpine shrub coverage proved to be negatively correlated with the contributions of new rain to river water, while alpine meadow coverage was positively correlated with the contributions of new rain. This would imply that increasing the relative coverage of alpine shrubs in this mountainous region of China may decrease the risk of flooding. (C) 2014 Elsevier B.V. All rights reserved
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