GLORIA

GEOMAR Library Ocean Research Information Access

feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    Publication Date: 2013-05-01
    Description: Human activities have significantly altered nitrogen (N) availability in most terrestrial ecosystems, with consequences for community composition and ecosystem functioning. While studies of how changes in N availability affect biodiversity and community composition are relatively common, much less is known about the effects of N inputs on the coupled biogeochemical cycling of N and phosphorus (P), and still fewer data exist regarding how increased N inputs affect the internal cycling of these two elements in plants. Nutrient resorption is an important driver of plant nutrient economies and of the quality of litter plants produce. Accordingly, resorption patterns have marked ecological implications for plant population and community fitness, as well as for ecosystem nutrient cycling. In a semi-arid grassland in northern China, we studied the effects of a wide-range of N inputs on foliar nutrient resorption of two dominant grasses, Leymus chinensis and Stipa grandis . After four years of treatments, N and P availability in soil and N and P concentrations in green and senesced grass leaves increased with increasing rates of N addition. Foliar N and P resorption significantly decreased along the N addition gradient, implying a resorption-mediated positive plant-soil feedback induced by N inputs. Furthermore, N:P resorption ratios were negatively correlated with the rates of N addition, indicating the sensitivity of plant N and P stoichiometry to N inputs. Taken together, the results demonstrate that N additions accelerate ecosystem uptake and turnover of both N and P in the temperate steppe and that N and P cycles are coupled in dynamic ways. The convergence of N and P resorption in response to N inputs emphasizes the importance of nutrient resorption as a pathway by which plants and ecosystems adjust in the face of increasing N availability. This article is protected by copyright. All rights reserved.
    Print ISSN: 1354-1013
    Electronic ISSN: 1365-2486
    Topics: Biology , Energy, Environment Protection, Nuclear Power Engineering , Geography
    Published by Wiley-Blackwell
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
  • 2
    Publication Date: 2018-10-12
    Description: After the asynchronous network of Yunnan Power Grid and China Southern Power Grid, the characteristics of small capacity and poor anti-disturbance capability of Yunnan Power Grid are highlighted. Changes in the power grid environment make the problem of three-phase voltage imbalance more likely to occur and may deteriorate. This paper studies the ability of photovoltaic three-phase unbalanced adaptability after asynchronous networking. A double-synchronized reference coordinate model for PV in the three-phase unbalanced condition was established. The influence of the voltage negative-sequence component of the grid on the DC voltage, output current and power of the inverter was studied. A scheme for suppressing oscillation by adding a notch filter is proposed. In Matlab/Simulink, the whole process simulation of wind turbine adaptability under three-phase unbalanced change is realized. The simulation results verify the correctness of the theoretical analysis and the effectiveness ...
    Print ISSN: 1755-1307
    Electronic ISSN: 1755-1315
    Topics: Geography , Geosciences , Physics
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
  • 3
    Publication Date: 2018-06-23
    Description: Remote Sensing, Vol. 10, Pages 999: Remote Sensing Image Compression Based on Direction Lifting-Based Block Transform with Content-Driven Quadtree Coding Adaptively Remote Sensing doi: 10.3390/rs10070999 Authors: Cuiping Shi Liguo Wang Junping Zhang Fengjuan Miao Peng He Due to the limitations of storage and transmission in remote sensing scenarios, lossy compression techniques have been commonly considered for remote sensing images. Inspired by the latest development in image coding techniques, we present in this paper a new compression framework, which combines the directional adaptive lifting partitioned block transform (DAL-PBT) with content-driven quadtree codec with optimized truncation (CQOT). First, the DAL-PBT model is designed; it calculates the optimal prediction directions of each image block and performs the weighted directional adaptive interpolation during the process of directional lifting. Secondly, the CQOT method is proposed, which provides different scanning orders among and within blocks based on image content, and encodes those blocks with a quadtree codec with optimized truncation. The two phases are closely related: the former is devoted to image representation for preserving more directional information of remote sensing images, and the latter leverages adaptive scanning on the transformed image blocks to further improve coding efficiency. The proposed method supports various progressive transmission modes. Experimental results show that the proposed method outperforms not only the mainstream compression methods, such as JPEG2000 and CCSDS, but also, in terms of some evaluation indexes, some state-of-the-art compression methods presented recently.
    Electronic ISSN: 2072-4292
    Topics: Architecture, Civil Engineering, Surveying , Geography
    Published by MDPI Publishing
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
  • 4
    Publication Date: 2018-12-20
    Description: The fruits of wild Pyracantha fortunaeana were taken from Sichuan Mianyang, Ya’an Shimian and Hanyuan, and the main nutrients were determined by selecting the fruits with vermeil and orange-red. The results showed that the content of Vc (10.36~45.30mg/100gFW) in the fruit of P. fortunaeana was very rich, and the K content of mineral elements was 145.36~195.78mg/100g, the Ca content was 76.56~166.02mg/100g, and the Mg content was 6.94~ 16.29 mg/100g. Among them, the content of Cu, Fe, Mn and Zn which had health care effects were high, which were extremely valuable for development and utilization. In the comparison of the nutrient content of P. fortunaeana in the same population, the orange-red fruit had greater development potential than the vermeil fruit, while under the same fruit color and different populations, Mianyang’s P. fortunaeana fruit was richer in nutrients. In general, Mianyang population was better than other two populations of P. for...
    Print ISSN: 1755-1307
    Electronic ISSN: 1755-1315
    Topics: Geography , Geosciences , Physics
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...