56 research outputs found

    Nutrition Diet of Grazing Sheep and Forage Supply on Natural Grassland

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    Forages are a major asset of any livestock operation and the foundation of most rations in a forage-based livestock system. The available nutrients in a forage influence individual animal production (e.g. gain per animal), while the amount of forage produced affects production per hectare. The relationship between voluntary food intake and animal productivity is well recognized. Many studies related to the regulation of food consumption by sheep and cattle have been reported (Provenza 1996). Willoughby (1958) dis-cussed a number of factors which might influence the herbage intake of grazing animals. By contrast, less attention has been given to the nutritional supply which influences the intake of herbage by grazing animals. It is necessary to know about animal daily nutrient requirements for production and forage supply in order to evaluate grazing capacity

    WPKI Certificate Verification Scheme Based on Certificate Digest Signature-Online Certificate Status Protocol

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    Aiming at the problems of the WPKI certificate verification schemes based on online certificate status protocol (OCSP), this paper proposes a WPKI certificate verification scheme based on the certificate digest signature-online certificate status protocol (CDS_OCSP). Compared with the existing schemes, the proposed scheme optimizes the number of communication connections between the communication entities and the network, reduces the consumption of the wireless network bandwidth in the certificate verification process, and uses the elliptic curves cipher- (ECC-) based encrypting/decrypting functions to sign and verify the certificate digest, which ensures the consistency of the verified certificates among the communication entities. The proposed scheme makes the certificate verification process more efficient and secure. The experimental results show that the proposed scheme effectively reduces the communication consumption of the wireless network and saves the storage space of the wireless entities

    Study of Highly Pixelated CdZnTe Detector for PET Applications

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    AbstractWe are investigating the feasibility of a high-resolution PET insert device based on a Cadmium Zinc Telluride (CdZnTe) detector with 350μm anode pixel pitch to be integrated into a conventional animal PET scanner to improve its image resolution to sub-500 micrometer range. In this work, we have used a simplified version of the future 2048-pixel CdZnTe planar detector with 250μm anode pixel size and 100μm gap. This simplified 9 anode pixel structure makes it possible to conduct experiments without a complete ASIC readout system (with 2048 channels) that is still under development. We characterized this CdZnTe detector by investigating it charge sharing, spatial resolution, and energy resolution. We imaged a Na-22 point source using the coincidence events between this 350μm pixelated CdZnTe detector and a lutetium oxyorthosilicate (LSO) based Siemens Inveon PET detector. The reconstructed PET image shows a resolution of 590μm full width at half maximum (FWHM) by using single-pixel events. When we included double-pixel charge sharing events in the image reconstruction, the image resolution was degraded to 655μm, but the sensitivity of the coincidence system increased 2.5 to 3 times

    The Genomes of Oryza sativa: A History of Duplications

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    We report improved whole-genome shotgun sequences for the genomes of indica and japonica rice, both with multimegabase contiguity, or almost 1,000-fold improvement over the drafts of 2002. Tested against a nonredundant collection of 19,079 full-length cDNAs, 97.7% of the genes are aligned, without fragmentation, to the mapped super-scaffolds of one or the other genome. We introduce a gene identification procedure for plants that does not rely on similarity to known genes to remove erroneous predictions resulting from transposable elements. Using the available EST data to adjust for residual errors in the predictions, the estimated gene count is at least 38,000–40,000. Only 2%–3% of the genes are unique to any one subspecies, comparable to the amount of sequence that might still be missing. Despite this lack of variation in gene content, there is enormous variation in the intergenic regions. At least a quarter of the two sequences could not be aligned, and where they could be aligned, single nucleotide polymorphism (SNP) rates varied from as little as 3.0 SNP/kb in the coding regions to 27.6 SNP/kb in the transposable elements. A more inclusive new approach for analyzing duplication history is introduced here. It reveals an ancient whole-genome duplication, a recent segmental duplication on Chromosomes 11 and 12, and massive ongoing individual gene duplications. We find 18 distinct pairs of duplicated segments that cover 65.7% of the genome; 17 of these pairs date back to a common time before the divergence of the grasses. More important, ongoing individual gene duplications provide a never-ending source of raw material for gene genesis and are major contributors to the differences between members of the grass family

    Author Correction:A consensus protocol for functional connectivity analysis in the rat brain

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    Cracking mechanism analysis and experimental verification of encapsulated module under high low temperature cycle considering residual stress

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    Aiming at the cracking failure of the modified epoxy resin encapsulated module as a result of interface failure under high low temperature cycles, numerical simulation and experimental studies were carried out. Firstly, the residual stress field in the encapsulated module was reconstructed after measuring the curing residual stresses in epoxy resin using the hole-drilling method. Temperature-dependent material models were developed after testing the mechanical and thermal characteristic parameters of encapsulated module components, such as modified epoxy resin, in high and low temperature conditions. Then, a finite element model of a high-reduction encapsulated module with multiple components, multiple interfaces, and complicated contacts was established considering residual stress and temperature effects. To simulate the failure behaviour of the resin-embedded part interfaces, the cohesive zone model was utilized. Finally, the stress and strain of the encapsulated module under high and low temperature cycles were simulated, and their distribution features and cracking failure mechanism were analyzed. The results indicate that regardless of the heating/cooling process, significant due to a mismatch in thermal expansion coefficients between the resin and the embedded parts. As the temperature approaches the glass transition temperature Tg, the difference grows dramatically. The resulting thermal stress, together with the residual stress, led to the interface failure in encapsulated module. The numerical results were in good agreement with the high and low temperature cycle test results of the encapsulated module, which verified the effectiveness of the analysis method and the established finite element model. The investigation provides an important reference for the high-reliability design of the encapsulation module

    Spatiotemporal Heterogeneity of Coastal Wetland Ecosystem Services in the Yellow River Delta and Their Response to Multiple Drivers

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    Understanding on the spatiotemporal interactions between ecosystem services (ESs) and social–ecological drivers is crucial for the design of sustainable development strategies for coastal wetlands. In this paper, we took the Yellow River Delta (YRD) as a case study, based on multiple evaluation methods to study the spatiotemporal dynamics of ESs in the YRD from 1980 to 2020. With the help of principal component analysis (PCA) for identification of multiple drivers, we researched the spatiotemporal differentiation and influence mechanism of drivers on ESs, using the coupling coordination degree (CCD) model and geographically and temporally weighted regression (GTWR) model, and subsequently provided the development strategy for each district in Dongying City. The results showed that (1) the patterns of ESs were spatially heterogeneous, with a fluctuating upward trend from 1980 to 2020, which was mainly affected by regulating service. (2) Our spatiotemporal analysis of ES interactions identified that cultural service was mainly disorder with other ESs. Nevertheless, in wetlands, various ESs can basically develop in a coordinated manner. (3) We integrated multiple drivers into five principal components by PCA, to which the response of ESs had spatial heterogeneity. (4) Consequently, we integrated spatiotemporal knowledge on ES interactions and their drivers into spatial planning

    Light Absorption Enhancement and Laser-Induced Damage Ability Improvement of Aluminum Alloy 6061 with Non-Porous Alumina/CdSe@Al2O3/SiO2 Functional Gradient Films

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    Numerical calculations of ultraviolet to near-infrared absorption spectra by cadmium selenide quantum dots (CdSe QDs) doped in anodic aluminum oxide pores were performed using a finite-difference time-domain model. The height, diameter, and periodic spacing of the pores were optimized. Light absorption by the dots was enhanced by increasing the height and decreasing the diameter of the pores. When the height was less than 1 μm, visible light absorption was enhanced as the spacing was reduced from 400 nm to 100 nm. No enhancement was observed for heights greater than 6 μm. Finally, the optical mode coupling of the aluminum oxide and the quantum dots was enhanced by decreasing the pore diameter and periodic spacing and increasing the height. Laser ablation verified light absorption enhancement by the CdSe QDs. The experiments verified the improvement in the laser-induced damage ability with a nanosecond laser at a wavelength of 355 nm after aluminum alloy 6061 was coated with functional films and fabricated based on numerical calculations

    Extended Rauch–Tung–Striebel Smoother for the State of Charge Estimation of Lithium-Ion Batteries Based on an Enhanced Circuit Model

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    The state of charge (SOC) of a lithium battery system is critical since it indicates the remaining operating hours, full charge time, and peak power of the battery. This paper recommends an extended Rauch–Tung–Striebel smoother (ERTSS) for estimating SOC. It is implemented based on an improved equivalent circuit model with hysteresis voltage. The smoothing step of ERTSS will reduce the estimation error further. Additionally, the genetic algorithm (GA) is employed for searching the optimal ERTSS’s smoothing time interval. Various dynamic cell tests are conducted to verify the model’s accuracy and error estimation deviation. The test results demonstrate that ERTSS’s SOC estimation error is limited to 4% with an initial error between −25 ∘C and 45 ∘C and that the root mean square error (RMSE) of ERTSS’s SOC estimation is approximately 5% lower than that of extended Kalman filter (EKF). The ERTSS improves the SOC estimation accuracy at all operating temperatures of batteries
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