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131.
132.
Safeguarding plants as seeds in ex situ collections is a cost effective element in an integrated plant conservation approach. The European Alps are a regional centre of plant diversity. Six institutions have established a regional network covering the European Alps which will conserve at least 500 priority plant species and which will improve the conservation status of plant species in grassland communities in the subalpine, alpine and nival altitudinal belts. Targeted research will expand the knowledge of the ecology of target species. Public engagement activities will raise the awareness for the importance of specific conservation actions in the European Alps.  相似文献   
133.
Automatic detection and tracking of pedestrians from a moving stereo rig   总被引:1,自引:0,他引:1  
We report on a stereo system for 3D detection and tracking of pedestrians in urban traffic scenes. The system is built around a probabilistic environment model which fuses evidence from dense 3D reconstruction and image-based pedestrian detection into a consistent interpretation of the observed scene, and a multi-hypothesis tracker to reconstruct the pedestrians’ trajectories in 3D coordinates over time. Experiments on real stereo sequences recorded in busy inner-city scenarios are presented, in which the system achieves promising results.  相似文献   
134.
Various processes have been proposed to explain how galaxy discs acquire their thickness. A simple diagnostic for ascertaining this 'heating' mechanism is provided by the ratio of the vertical to radial velocity dispersion components. In a previous paper we have developed a technique for measuring this ratio, and demonstrated its viability on the Sb system NGC 488. Here we present follow-up observations of the morphologically similar Sab galaxy NGC 2985, still only the second galaxy for which this ratio has been determined outside the solar neighbourhood. The result is consistent with simple disc-heating models that predict ratios of σ z σ R less than one.  相似文献   
135.
About 1 mg/g dw Cu2+ and 8 mg/g dw Fe2+ were found in roots of reed plants when fed with heavy metal concentrations of 100 μM Cu2+ and 10 mM Fe2+ under hypoxia. Roots seemed to act as a kind of filter since the amounts in rhizomes were only 0.06 mg Cu2+/g dw and 2 mg Fe2+/g dw. Increased contents of both ions reduced posthypoxic respiration capacity by 40–50% and also the sum of adenylates (ATP, ADP, AMP) by the same order of magnitude, although energy charge values remained above 0.85 in Cu2+ and 0.79 in Fe2+ treatments. Energy metabolism of rhizomes was not affected. Copper and iron contents of roots as well as of rhizomes were high enough to induce oxidative stress when roots were fed with 40 μM Cu2+ and 1 mM Fe2+, respectively.From our results we conclude that increased, but environmentally attainable, amounts of copper and reduced iron ions disturb root energy metabolism, and therefore root functioning and development. Latent injuries, based on oxidative stress, may be harmful for roots and rhizomes under long term exposure.  相似文献   
136.
137.
A 182-year long record of trace metal concentrations of aluminum, zinc and lead was reconstructed from a massive Porites coral skeleton from southeastern Hong Kong to evaluate the impacts of anthropogenic activity on the marine environment. Zn/Ca and Pb/Ca ratios fluctuate synchronously from the early 19th century to the present, indicating that the marine environment has been anthropogenically influenced since industrialization. Additionally, land reclamation, mining, and ship building activities are recorded by elevated Al/Ca ratios from 1900 to 1950. The coral record indicates that high levels of Zn, Pb and Al occur coincidentally with local wars, and may have contributed to partial colony mortality. Pb/Ca does not correlate well with hemispheric proxy records after 1950, indicating that coastal corals may be recording local rather than hemispheric contamination. Pb/Ca levels in Hong Kong, Guangdong and Hainan corals imply a continuous supply of Pb-based contamination to southern China not reflected in hemispheric signals.  相似文献   
138.
The pattern speed is one of the fundamental parameters that determines the structure of barred galaxies. This quantity is usually derived from indirect methods or by employing model assumptions. The number of bar pattern speeds derived using the model-independent Tremaine & Weinberg technique is still very limited. We present the results of model-independent measurements of the bar pattern speed in four galaxies ranging in Hubble type from SB0 to SBbc. Three of the four galaxies in our sample are consistent with bars being fast rotators. The lack of slow bars is consistent with previous observations and suggests that barred galaxies do not have centrally concentrated dark matter haloes. This contradicts simulations of cosmological structure formation and observations of the central mass concentration in nonbarred galaxies.  相似文献   
139.
The erosion of rocks rich in organic matter typically leads to the complete mineralization of the organic material. However, in some cases, it is re-deposited to become a part of sediments once more. This process should be considered to be a part of global carbon cycle, possibly much more significant than assumed to-date. The research presented here aims to characterize re-worked organic matter occurring in post-glacial sediments of southern part of Poland, in the Oder river valley (the Racibórz town region, Miocene, Pleistocene and Holocene age). Organic substances extracted from the sediments originated from organic matter that had resided in rocks eroded by glaciers. Sediments were sampled in two boreholes which sediments were correlated. Sediments were extracted and extracts analyzed with gas chromatography-mass spectrometry (GC-MS) to assess distributions of biomarker groups. Organic matter of selected samples was pre-concentrated and analyzed with Py/GC-MS. In the extracts several biomarker parameters of source/environment and thermal maturity were calculated. Organic substances in the investigated sediments come from variable re-deposited organic matter occurring in rocks eroded by glaciers. Three main parent types of re-deposited organic material are identified showing variable geochemical features: 1) organic matter of recent or almost recent age being the source of polar labile compounds; probably formed in situ, 2) re-deposited organic matter of the middle diagenesis showing features similar to lignites (huminite reflectance Rf ~ 0.25–0.35%) deriving from angiosperm remains, mainly monocotyledons and to the lower extend also deciduous trees, 3) re-deposited organic matter at the middle catagenesis (Rf ~ 0.65–0.75%) being the source of most of aromatic hydrocarbons and biomarkers such as steranes, hopanes of the more thermally advanced distribution type. Its geochemical properties and assumed directions of sediment transport indicate bituminous coals of Upper Silesian Coal Basin together with coaly shales as a possible source of this organic matter. Such mixed origin of organic matter caused large discrepancies in values of thermal maturity parameters depending on input from the particular sources and occurrence both geochemical biomarkers and their biochemical precursors in the same samples.  相似文献   
140.
针对摄影测量三维建模向全自动化发展的背景,该文基于SURE摄影测量软件,实现了自动化建立三维场景。阐述了主要的处理环节,包括密集匹配、平差交会、三角构网及贴图等,可生产的产品包括密集点云、真正射影像、数字表面模型、不规则三角网及三维贴图场景;通过分析匹配效率及点云和数字表面模型的精度,显示出其产品均可达到测量级精度。使用高重叠度或倾斜影像,SURE还可以生产出精美的三维城市模型;充分挖掘每一个像素的高精度三维坐标,是其在同类软件中的一大特色。  相似文献   
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