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71.
Many technologies in precision agriculture (PA) require image analysis and image- processing with weed and background differentiations.
The detection of weeds on mulched cropland is one important image-processing task for sensor based precision herbicide applications.
The article introduces a special vegetation index, the Difference Index with Red Threshold (DIRT), for the weed detection
on mulched croplands. Experimental investigations in weed detection on mulched areas point out that the DIRT performs better
than the Normalized Difference Vegetation Index (NDVI). The result of the evaluation with four different decision criteria
indicate, that the new DIRT gives the highest reliability in weed/background differentiation on mulched areas. While using
the same spectral bands (infrared and red) as the NDVI, the new DIRT is more suitable for weed detection than the other vegetation
indices and requires only a small amount of additional calculation power. The new vegetation index DIRT was tested on mulched
areas during automatic ratings with a special weed camera system. The test results compare the new DIRT and three other decision
criteria: the difference between infrared and red intensity (Diff), the soil-adjusted quotient between infrared and red intensity
(Quotient) and the NDVI. The decision criteria were compared with the definition of a worse case decision quality parameter
Q, suitable for mulched croplands. Although this new index DIRT needs further testing, the index seems to be a good decision
criterion for the weed detection on mulched areas and should also be useful for other image processing applications in precision
agriculture.
The weed detection hardware and the PC program for the weed image processing were developed with funds from the German Federal
Ministry of Education and Research (BMBF). 相似文献
72.
Planetary Stewardship in an Urbanizing World: Beyond City Limits 总被引:1,自引:0,他引:1
Sybil P. Seitzinger Uno Svedin Carole L. Crumley Will Steffen Saiful Arif Abdullah Christine Alfsen Wendy J. Broadgate Frank Biermann Ninad R. Bondre John A. Dearing Lisa Deutsch Shobhakar Dhakal Thomas Elmqvist Neda Farahbakhshazad Owen Gaffney Helmut Haberl Sandra Lavorel Cheikh Mbow Anthony J. McMichael Joao M. F. deMorais Per Olsson Patricia Fernanda Pinho Karen C. Seto Paul Sinclair Mark Stafford Smith Lorraine Sugar 《Ambio》2012,41(8):787-794
Cities are rapidly increasing in importance as a major factor shaping the Earth system, and therefore, must take corresponding responsibility. With currently over half the world’s population, cities are supported by resources originating from primarily rural regions often located around the world far distant from the urban loci of use. The sustainability of a city can no longer be considered in isolation from the sustainability of human and natural resources it uses from proximal or distant regions, or the combined resource use and impacts of cities globally. The world’s multiple and complex environmental and social challenges require interconnected solutions and coordinated governance approaches to planetary stewardship. We suggest that a key component of planetary stewardship is a global system of cities that develop sustainable processes and policies in concert with its non-urban areas. The potential for cities to cooperate as a system and with rural connectivity could increase their capacity to effect change and foster stewardship at the planetary scale and also increase their resource security. 相似文献
73.
H Segner M Wenger AM Möller B Köllner A Casanova-Nakayama 《Environmental science and pollution research international》2011,19(7):2465-2476
Numerous environmental chemicals, both long-known toxicants such as persistent organic pollutants as well as emerging contaminants such as pharmaceuticals, are known to modulate immune parameters of wildlife species, what can have adverse consequences for the fitness of individuals including their capability to resist pathogen infections. Despite frequent field observations of impaired immunocompetence and increased disease incidence in contaminant-exposed wildlife populations, the potential relevance of immunotoxic effects for the ecological impact of chemicals is rarely considered in ecotoxicological risk assessment. A limiting factor in the assessment of immunotoxic effects might be the complexity of the immune system what makes it difficult (1) to select appropriate exposure and effect parameters out of the many immune parameters which could be measured, and (2) to evaluate the significance of the selected parameters for the overall fitness and immunocompetence of the organism. Here, we present - on the example of teleost fishes - a brief discussion of how to assess chemical impact on the immune system using parameters at different levels of complexity and integration: immune mediators, humoral immune effectors, cellular immune defenses, macroscopical and microscopical responses of lymphoid tissues and organs, and host resistance to pathogens. Importantly, adverse effects of chemicals on immunocompetence may be detectable only after immune system activation, e.g., after pathogen challenge, but not in the resting immune system of non-infected fish. Current limitations to further development and implementation of immunotoxicity assays and parameters in ecotoxicological risk assessment are not primarily due to technological constraints, but are related from insufficient knowledge of (1) possible modes of action in the immune system, (2) the importance of intra- and inter-species immune system variability for the response against chemical stressors, and (3) deficits in conceptual and mechanistic assessment of combination effects of chemicals and pathogens. 相似文献
74.
75.
Limitations for heavy metal release during thermo-chemical treatment of sewage sludge ash 总被引:1,自引:0,他引:1
Nowak B Perutka L Aschenbrenner P Kraus P Rechberger H Winter F 《Waste management (New York, N.Y.)》2011,31(6):1285-1291
Phosphate recycling from sewage sludge can be achieved by heavy metal removal from sewage sludge ash (SSA) producing a fertilizer product: mixing SSA with chloride and treating this mixture (eventually after granulation) in a rotary kiln at 1000 ± 100 °C leads to the formation of volatile heavy metal compounds that evaporate and to P-phases with high bio-availability. Due to economical and ecological reasons, it is necessary to reduce the energy consumption of this technology. Generally, fluidized bed reactors are characterized by high heat and mass transfer and thus promise the saving of energy. Therefore, a rotary reactor and a fluidized bed reactor (both laboratory-scale and operated in batch mode) are used for the treatment of granulates containing SSA and CaCl2. Treatment temperature, residence time and - in case of the fluidized bed reactor - superficial velocity are varied between 800 and 900 °C, 10 and 30 min and 3.4 and 4.6 m s−1. Cd and Pb can be removed well (>95 %) in all experiments. Cu removal ranges from 25% to 84%, for Zn 75-90% are realized. The amount of heavy metals removed increases with increasing temperature and residence time which is most pronounced for Cu.In the pellet, three major reactions occur: formation of HCl and Cl2 from CaCl2; diffusion and reaction of these gases with heavy metal compounds; side reactions from heavy metal compounds with matrix material. Although, heat and mass transfer are higher in the fluidized bed reactor, Pb and Zn removal is slightly better in the rotary reactor. This is due the accelerated migration of formed HCl and Cl2 out of the pellets into the reactor atmosphere. Cu is apparently limited by the diffusion of its chloride thus the removal is higher in the fluidized bed unit. 相似文献
76.
77.
The quality of Albanian natural waters and the human impact 总被引:6,自引:0,他引:6
Albania possesses a wealth of aquatic ecosystems, many of enormous natural and biological value, such as the Lakes Ohrid, Prespa and Shkodra, glacial lakes, river valleys, and coastal lagoons. Although many habitats are highly polluted by inorganic and organic wastes, detailed knowledge on the water quality is still lacking. For the first time, an environmental assessment of the water quality is presented and the main polluting sources identified. As a consequence, a systematic control and the establishment of routine monitoring of surface and groundwater is proposed, which elucidates the present environmental state and helps to develop new strategies of waste and wastewater management. It would help allow Albania to reach an international standard in environmental protection, as a part of UNECE Convention, the Mediterranean Action Plan, the MAP/UNEP Medpol Program and the Basel Convention. 相似文献
78.
Helmut Bruns 《Die Naturwissenschaften》1979,66(4):197-201
Numerous computer programs have gained entry into drug research; some of them are already used as a matter of routine, whereas others are still being tested. The special advantages of the use of computer programs are shown for the two fields “computer-assisted synthesis planning” and “quantitative structure-activity relationships”. Several aspects of cooperation between man and computer are briefly discussed. 相似文献
79.
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