1,161 research outputs found
Cymbidium purpureisepalum (Orchidaceae; Epidendroideae), a new species from China: evidence from morphological and molecular data
No full textZhu, Meng-Jia, Ke, Shijie, Zhao, Xuewei, Wang, Qian-Qian, Chen, Guizhen, Liu, Zhong- Jian, Lan, Siren (2022): Cymbidium purpureisepalum (Orchidaceae; Epidendroideae), a new species from China: evidence from morphological and molecular data. Phytotaxa 538 (3): 225-233, DOI: 10.11646/phytotaxa.538.3.5, URL: http://dx.doi.org/10.11646/phytotaxa.538.3.
A Novel Dynamic Decoupling Approach Based on Command Shaping for Overactuated Motion Systems
No full textEstimation of potential surface ponding in agriculture using UAV-SfM
Get PDFAmong the environmental problems that could affect agriculture, one of the most critical is ponding. Ponding is the water storage on the surfaces in concavities or small depressions, due to soil saturation. It can seriously affect crops and the management of agricultural landscapes. It is caused by prolonged rainfall events, soil type, or by wrong mechanization practices. Indeed, the increased pressure of heavy machinery can cause topsoil compaction or a subsoil hard pan directly under the ploughing depth, inducing run-off, soil loss and waterlogging. In order to better understand this issue, and therefore provide suitable solutions to reduce ponding risk, it is necessary to represent in details the surface morphology. In the last decade, a range of new remote-sensing techniques have led to a dramatic increase in terrain information, providing new opportunities for a better understanding of Earth surface processes based on geomorphic signatures. Among these, the Unmanned Aerial Vehicles (UAVs) combined with the Structure-from-Motion (SfM) photogrammetry technique represent undoubtedly the most interesting advance in the Earth observation and understanding of Earth surface processes. UAV-acquired imagery may provide a low-cost, rapid, and flexible alternative to airborne LiDAR for geomorphological mapping.
In this work UAV-SfM data are used to obtain high-resolution Digital Terrain Model (DTM) useful to analyze and evaluate the risks of water ponding at farm level in a mid-size agricultural Mediterranean catchment in northern Italy. Intensive photogrammetric surveys were carried out using a UAV while a GNSS in RTK (Real-Time Kinematic) mode was used to collect Ground Control Points (GCPs) and Check Points (CPs), fundamental for georeferencing process and SfM error analysis. The potential water depth was calculated using the Relative Elevation Attribute (REA) algorithm, a methodology successfully used in other contexts (Tarolli et al. 2019). The detection of more pronounced concavities and convexities allowed an estimation and mapping of the potential ponding conditions, thus providing a useful indication for a better environmental management in agriculture
FIGURE 4. Cymbidium purpureisepalum. A. Flowering plant. B. Flower, front view. C. Flower, back view. D in Cymbidium purpureisepalum (Orchidaceae; Epidendroideae), a new species from China: evidence from morphological and molecular data
No full textFIGURE 4. Cymbidium purpureisepalum. A. Flowering plant. B. Flower, front view. C. Flower, back view. D. Structure of the flower. E. Flower of C. serratum. F. Flowers of C. tortisepalumPublished as part of Zhu, Meng-Jia, Ke, Shijie, Zhao, Xuewei, Wang, Qian-Qian, Chen, Guizhen, Liu, Zhong- Jian & Lan, Siren, 2022, Cymbidium purpureisepalum (Orchidaceae; Epidendroideae), a new species from China: evidence from morphological and molecular data, pp. 225-233 in Phytotaxa 538 (3) on page 230, DOI: 10.11646/phytotaxa.538.3.5, http://zenodo.org/record/633678
FIGURE 3 in Cymbidium purpureisepalum (Orchidaceae; Epidendroideae), a new species from China: evidence from morphological and molecular data
No full textFIGURE 3. Phylogenetic relationships of C. purpureisepalum based on nuclear DNA data (nrITS). The three numbers near the nodes are Bayesian posterior probabilities (PP), maximum likelihood bootstrap percentages (BP ML) and maximum parimony bootstrap percentages (BP MP). "-" indicates that the node is incongruent between the topology of the Bayesian tree and the MP/ML trees.Published as part of Zhu, Meng-Jia, Ke, Shijie, Zhao, Xuewei, Wang, Qian-Qian, Chen, Guizhen, Liu, Zhong- Jian & Lan, Siren, 2022, Cymbidium purpureisepalum (Orchidaceae; Epidendroideae), a new species from China: evidence from morphological and molecular data, pp. 225-233 in Phytotaxa 538 (3) on page 229, DOI: 10.11646/phytotaxa.538.3.5, http://zenodo.org/record/633678
Analyzing topographic changes through LiDAR and SfM techniques: assessing the deposition-erosion patterns and estimation of debris-flow volume in the eastern Italian Alps
No full text
An Adaptive Data-Driven Iterative Feedforward Tuning Approach Based on Fast Recursive Algorithm: With Application to A Linear Motor
No full textThe feedforward control can effectively improve the servo performance in applications with high requirements of velocity and acceleration. The iterative feedforward tuning method (IFFT) enables the possibility of both removing the need for prior knowledge of the system plant in model-based feedforward and improving the extrapolation capability for varying tasks of iterative learning control. However, most of IFFT methods require to set the number of basis functions in advance, which is inconvenient to the system design. To tackle this problem, an adaptive data-driven IFFT based on fast recursive algorithm (IFFT-FRA) is developed in this paper. Explicitly, based on FRA the proposed approach can adaptively tune the feedforward structure, which significantly increases the intelligence of the approach. Additionally, a data-based iterative tuning procedure is introduced to achieve the unbiased estimation of parameters optimization in presence of noise. Comparative experiments on a linear motor confirms the effectiveness of the proposed approach. IEE
Variation of postharvest quality attributes and aroma development of Xiaobai apricot during storage at near freezing temperature
No full textGold(I)-catalyzed tandem 1,3-acyloxy migration/ferrier rearrangement and its application
No full textDuring our investigation to study the transition metal mediated C-glycosylation, a gold(I)-catalyzed tandem 1,3-acyloxy migration/Ferrier rearrangement has been serendipitously discovered and we have went on to establish a new concise way to furnish vinyl-C-glycoside product and 8-oxabicyclo[3.2.1]octane derivatives in good yields and exclusive diastereoselectivity.
The intermolecular gold(I)-catalyzed tandem 1,3-acyloxy migration/Ferrier rearrangement with glycals and propargylic esters allowed access to the a, (E)-selective C-vinyl glycoside products in the presence of PPh3AuOTf. Both D-glucal and D-glactal could be applied into the C-vinyl glycosylation through this methodology.
The intramolecular gold(I)-catalyzed tandem 1,3-acyloxy migration/Ferrier rearrangement with glycal-linked propargyl esters allowed access to the optically pure 8-oxabicyclo[3.2.1]octane derivatives in the presence of PPh3AuSbF6. The reaction mechanism was further investigated with a series of experiments.
In addition, the 8-oxabicyclo[3.2.1]octane products was evaluated for their cytostatic activities against selected human cancer cells lines and most compounds have shown promising inhibitory effects with the IC50.value as low as 2.31 µM, which suggested that these oxabicyclo[3.2.1]octane derivatives could be potential anti-tumor reagents.
Furthermore, it was found that the 8-oxabicyclo[3.2.1]octanes with divinyl ketone motif could undergo asymmetric interrupted Nazarov cyclization to generate the optically pure 11-oxatricyclo[5.3.1.0]undecanes catalyzed by BF3•OEt2, suggesting the possibility of applying the methodology in total synthesis of complex natural product.Doctor of Philosophy (SPMS
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