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Efforts to improve the efficiency and efficacy of tree structure and crown architecture measurement are necessary to reduce error associated with indirect estimation of volume, which affects biophysical and ecosystem modelling, as well as resource assessment. In this short communication, we test the potential for a commercial SfM-MVS (Structure from Motion coupled with Multiple-View Stereophotogrammetry) software package, Photoscan-Professional, to accurately determine tree height, stem diameter, and eventually volume. SfM is a technique in computer vision, which calculates the 3D position of objects in a scene from a series of photographs. It uses a technique assuming that an object in a 3D scene is located on a vector between the image of the object in the camera and the object itself. The technique allows the construction of a 3D pointcloud, such as the one produced by laser technologies – terrestrial or airborne LiDAR. SfM requires no camera calibration or control points to construct an initial model. Moreover, it is a low-cost alternative to laser technologies. The second part of our method – MVS – is a visualization technique that reconstructs a 3D textured mesh of the scene from the SfM-derived pointcloud and RGB photographs. As a proof of concept, our methods were limited to two scenarios: (1) a single potted tree in a lab environment, where exact measurements could be made, and (2) two trees of different species and size in natural environments to test feasibility outside the laboratory. Precise measurements of tree height and stem diameter were compared with estimates obtained from the 3D model created using SfM-MVS. The results indicate that the SfM method is a promising – and inexpensive – alternative to terrestrial LiDAR and 3D scanners. Tree height estimates had error of 2.59%, while stem diameter estimates had error of 3.7%. The MVS algorithm used in this study was developed for plan surfaces such as topography or ‘compact’ objects and does not provide a representative 3D mesh for slender trees, although it works well for large stems. The authors link this disparity to the complex branching structure of trees.Future work requires (1) the development of effective automated volume reconstruction software specific to trees, and (2) the validation of the wide-scale applicability of the technology, which must include trees of various size, species, and growth forms. Moreover, future testing must include more complex environments, such as heterogeneous urban sites or closed-canopy forest sites where the proximity of other features may limit the utility of the new technology. 相似文献
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Hermo GA Turic E Angelico D Scursoni AM Gomez DE Gobello C Alonso DF 《Journal of the American Animal Hospital Association》2011,47(1):21-27
Desmopressin (DDAVP) is a vasopressin peptide analog with hemostatic properties that has been successfully used during surgery in patients with bleeding disorders. Recently published experimental and clinical data indicate that perioperative administration of DDAVP can minimize spread and survival of residual mammary cancer cells. The central aim of this study was to explore the effect of perioperative DDAVP and its relation to histologic grade in bitches with locally advanced mammary carcinoma. Of the 32 dogs initially recruited, 28 intact bitches with mammary carcinoma tumors stage III or IV were ultimately included. These dogs were randomized to receive DDAVP at intravenous doses of 1 μg/kg (n=18) or saline solution as placebo (n=10). En bloc mastectomy of the affected gland(s) was performed. Tumor malignancy was graded by the method of Elston and Ellis into well-differentiated (grade 1), moderately differentiated (grade 2), or poorly differentiated (grade 3). DDAVP therapy significantly prolonged the disease-free survival (P<0.001) and overall survival (P<0.01) in bitches with grade 2 or 3 carcinomas compared with bitches in the control group. No significant difference in disease-free period or overall survival was found between treatment groups in bitches with grade 1 tumors. The present data suggest that DDAVP may be an excellent candidate as a surgical adjuvant in the management of aggressive cancers in small animals. More research in this field is warranted. 相似文献
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Phragmidium violaceum (Pv) isolate F15 was released for biological control of invasive European blackberry in Australia in 1991–1992. This study reports variation in the pathogenicity of isolate F15 and Pv isolates SA1, V1 and V2, collected in southeastern Australia in 1997 or 1998, on a broad sample of genetically variable European blackberry clones collected in 1996–2000. The use of whole shoots or detached leaflet discs led to the same conclusions about the relative susceptibility of a blackberry clone to a particular Pv isolate. Moderate to relatively high numbers of uredinia developed on all 25 blackberry clones inoculated with isolate V1, whereas no or few uredinia of isolates V2 and SA1 developed on Rubus erythrops clone EB20, three clones of Rubus leucostachys (EB9, EB19 and 960804) or Rubus sp. clone SR43. Pv isolate F15 differed from the three isolates collected in Australia in that no or few uredinia of F15 developed on Rubus polyanthemus clone 961107 or three clones of Rubus laciniatus (EB22, KE1, SR14). Isolate F15 also differed from isolates V1 and V2 for the density of uredinia as a function of leaf age in a clone of Rubus anglocandicans found widely in Australia. Isolates V1 and V2 ceased production of uredinia on leaves older than 16 days, whereas Pv isolate F15 continued production of uredinia beyond this leaf age. This study informed selection of additional Pv isolates from Europe for release in Australia in 2004. 相似文献
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Fletcher LN Hesman BE Irwin PG Baines KH Momary TW Sanchez-Lavega A Flasar FM Read PL Orton GS Simon-Miller A Hueso R Bjoraker GL Mamoutkine A del Rio-Gaztelurrutia T Gomez JM Buratti B Clark RN Nicholson PD Sotin C 《Science (New York, N.Y.)》2011,332(6036):1413-1417
Saturn's slow seasonal evolution was disrupted in 2010-2011 by the eruption of a bright storm in its northern spring hemisphere. Thermal infrared spectroscopy showed that within a month, the resulting planetary-scale disturbance had generated intense perturbations of atmospheric temperatures, winds, and composition between 20° and 50°N over an entire hemisphere (140,000 kilometers). The tropospheric storm cell produced effects that penetrated hundreds of kilometers into Saturn's stratosphere (to the 1-millibar region). Stratospheric subsidence at the edges of the disturbance produced "beacons" of infrared emission and longitudinal temperature contrasts of 16 kelvin. The disturbance substantially altered atmospheric circulation, transporting material vertically over great distances, modifying stratospheric zonal jets, exciting wave activity and turbulence, and generating a new cold anticyclonic oval in the center of the disturbance at 41°N. 相似文献
138.
Ihee H Lobastov VA Gomez UM Goodson BM Srinivasan R Ruan CY Zewail AH 《Science (New York, N.Y.)》2001,291(5503):458-462
Ultrafast electron diffraction (UED) has been developed to study transient structures in complex chemical reactions initiated with femtosecond laser pulses. This direct imaging of reactions was achieved using our third-generation apparatus equipped with an electron pulse (1.07 +/- 0.27 picoseconds) source, a charge-coupled device camera, and a mass spectrometer. Two prototypical gas-phase reactions were studied: the nonconcerted elimination reaction of a haloethane, wherein the structure of the intermediate was determined, and the ring opening of a cyclic hydrocarbon containing no heavy atoms. These results demonstrate the vastly improved sensitivity, resolution, and versatility of UED for studying ultrafast structural dynamics in complex molecular systems. 相似文献
139.
A. Perez-Espinosa J. Moreno-Caselles R. Moral M. D. Perez-Murcia I. Gomez 《Archives of Agronomy and Soil Science》2013,59(3):273-278
The effects of increased cobalt additions (0, 50, 100 and 200 v mg v kg m 1 soil) in sewage sludge-amended soil on organic matter, N Kjeldahl, ammonium and nitrate were studied in this experiment. Three different rates of sewage sludge were applied (0, 30 and 60 v tn v ha m 1 ) to soil as main plots, using tomato (Lycopersicum esculentum Mill var. Ramy) such testing cultivation. Plant biomass and nitrogen content in tomato leaf were also monitored. The organic matter in the soil was clearly affected by the fertilization. N Kjeldahl, ammonium and nitrate were favoured by organic treatments. Co seemed to reduce the transformation of ammonium to nitrate on amended soils, with accumulation of ammonium forms, especially at the higher application rates of sewage sludge. This incidence of Co on nitrogen species in soil decreased with the time of experiment, probably due to the reduction of availability of the pollutant. Aerial biomass production and nitrogen content in leaf were increased for the organic fertilization compared to the control. Only very high levels of Co in soil reduced significantly the aerial biomass production of tomato plants in amended soils. Co seemed to induce a decrease of the nitrogen in leaf in the amended soils, but not for the non-fertilized soils. 相似文献
140.
Natalia Gomez 《山东饲料》2014,(5):215-216
China's growing participation in Latin American countries has been seen as a massive threat on the region 's manufacturing sector. Is it really this significant when it comes to its impact on manufacturing employment?With this project I pretend to examine the relationship between the bilateral commerce from China and Colombia in the textile a sector between the years 2000-2012. By examining the data I want to find out what is the correlation between jobs losses in Colombia's textile industry and the imports from China in the same industry.Analyzing the sector of textile is very significant to the country.It represents employment and production of added value products in an industry that has not only social impact but also historical meaning for the country. 相似文献