Courtship feeding, food sharing, or tolerated food theft among paired Red-crested Pochards (Netta rufina)?

Red-crested Pochards (Netta rufina) have been observed feeding on plants brought by their mates to the water surface, and this behaviour has been traditionally considered as courtship feeding. In this paper I report on this behaviour and examine its behavioural context. Females fed more frequently than males on plants brought by their mates to the surface, and this behaviour always occurred among paired birds. Individuals that procured the food plants were never observed offering them to their mates, but the latter simply approached the former as they surfaced with plants. The main advantages of this feeding behaviour would be to increase intake rates, as well as to reduce the feeding costs, as no time is spent searching for food underwater. Intake rates of individuals that procured the food were negatively affected when their mates profited from such food. Probably because of this, individuals that procured the food plants surfaced immediately after the feeding interaction with smaller quantities of food than before. This may be a strategy to discourage some individuals from feeding on plants brought to the surface by their mates, because this would allow the individuals that procure the food to ingest it before others start feeding on the plants. In this light, this feeding behaviour should not be considered as courtship feeding. Depending on whether pair bonds are maintained or split before breeding, this behaviour should be considered either as food sharing or tolerated food theft.Peer Reviewe

Characterization of condensed tannins from purple prairie clover (Dalea purpurea Vent.) conserved as either freeze-dried forage, sun-cured hay or silage

Conservation methods have been shown to affect forage nutrient composition and value, but little information is available about the effect of forage conservation on plant condensed tannins (CT). The objective of this study was to assess the effects of conservation method on the concentration, chemical composition and biological activity of CT. Whole-plant purple prairie clover (PPC, Dalea purpurea Vent.) was harvested at full flower and conserved as freeze-dried forage (FD), hay (HAY) or silage (SIL). Concentration of CT in conserved PPC was determined by the butanol-HCl-acetone method. Structural composition, protein-precipitation capacity and anti-bacterial activity of CT isolated from conserved forage were determined by in situ thiolytic degradation followed by HPLC-MS analysis, a protein precipitation assay using bovine serum albumin and ribulose 1,5-disphosphate carboxylase as model proteins and by an Escherichia coli (E. coli) growth test, respectively. Conservation method had no effect on concentration of total CT, but ensiling decreased (p HAY > SIL. E. coli growth n M9 medium was inhibited by 25-100 µg/mL of CT isolated from FD, HAY and SIL (p < 0.05), but preservation method had no effect on the ability of CT to inhibit bacterial growth. The results demonstrated that ensiling decreased the extractability and protein-precipitating capacity of CT by increasing the proportions of PC. Purple prairie clover conserved as hay retained more biologically active CT than if it was conserved as silage

Lithium niobate thin films on diamond substrates for SAW devices

Lithium niobate thin films have been grown on diamond/silicon substrates by metallo-organic decomposition and radio frequency (R. F.) magnetron sputtering. The surface acoustic wave (SAW) characterizations of the multilayer lithium niobate/diamond/silicon are calculated. The lithium niobate thin films as well as the diamond/silicon substrates are structurally analyzed using techniques such as Bragg X-ray diffraction, scanning electron microscopy, atomic force microscopy, electron microprobe, and Raman spectroscopy to determine their crystal structure, surface morphology and composition distribution. With the use of a lift-off photolithography planar process, surface acoustic wave filter devices on substrates such as lithium niobate single crystal plates, zinc oxide/diamond/silicon, and lithium niobate/diamond/silicon, are fabricated. Microwave characterizations, such as the frequency response, of these filters are measured, and their impulse response in the time domain are obtained by fast Fourier transformation. SAW activities for LiNbO3/diamond/silicon structure are observed. Discussions about the results and further improvements are presented

Teaching reform of Analog Electronic Technology Experiment Course under the Background of Artificial Intelligence

This paper briefly describes the implementation of the “multi-level” experimental teaching mode of “combination of hardware and software” and “combination of online and offline” in the experimental course of Analog Electronic Technology, and carries out the experimental teaching reform by combining the problem-oriented teaching mode. It has proved that the reconstructed experimental teaching system has effectively stimulated students’ interest in learning, and the teaching effect has been significantly improved

Effects of Octacosanol Extracted from Rice Bran on the Laying Performance, Egg Quality and Blood Metabolites of Laying Hens

A 42-d study with 384 Hy-line brown laying hens was conducted to assess the effects of dietary octacosanol supplementation on laying performance, egg quality and blood metabolites of laying hens. Hens were randomly allocated into 4 dietary groups of 8 cages each, which were fed basal diet supplemented with 0 (Control), 9 (OCT9), 18 (OCT18), and 27 (OCT27) mg/kg diet of octacosanol isolated from rice bran, respectively. The experiment was conducted in an environmental controlled house and hens were fed twice daily for ad libitum intake. Laying performance was determined over the 42-d period, and egg quality as well as blood metabolites were estimated on d 21 and d 42. Diets in OCT18 and OCT27 increased (p0.05) among treatments. Results demonstrate that supplementing 18 to 27 mg/kg diet of rice bran octacosanol can improve laying rate and egg quality and reduce blood lipid of laying hens

Bamboo Fiber-based Insulating Paper: A Potential Choice towards Greener Power and Paper Industries

Insulating paper is the key material utilized in ultra-high voltage (UHV) projects, and it affects the safe and stable operation of the whole power system. Cellulose fiber-based insulating paper, having the advantages of low price and environmental friendliness, has been widely used as the preferred insulating material for certain transformers. Bamboo, as a fast-growing raw material, has a favorable fiber length and its carbon sequestration is better than that of wood. Bamboo can be potentially used as a new raw material for insulating paper, thus promoting the green development of the power and paper industry. This article mainly discusses the challenges and potentials of bamboo fiber-based insulating paper and the opportunities of bamboo fiber-based paper materials

On Geometric Correction Method of BJ-1 Panchromatic Image Covering Kingdom of Lesotho

The purpose is to find a suitable geometric correction method of BJ-1 panchromatic image covering Kingdom of Lesotho. The methods are carrying out two geo-correction experiments based on the push-broom model and the projective transform model for BJ-1 small satellite real panchromatic covering flat and mountain area of Lesotho. Results show that the projective transform model has equal or higher accuracy compared to the push-broom model. Conclusion is the projective transform model can be used in producing land use image map

Analysis of Rural Development Factors: A Case Study of Hebei Province

On the basis of survey, drawing on economic growth theory, we analyze the main form of exogenous growth and regional applicability in Hebei Province, and point out that some exogenous driving forces are effective ways to accelerate rural construction, such as "the promotion of agriculture by industry" and "developing the rural areas with the aid of the urban areas". However, human capital, technology, incentive institutional arrangement, agricultural industry clusters and other endogenous growth factors are fundamental to sustainable development of rural construction, so it is necessary to make them play a fundamental role in increasing farmers' income and promoting agricultural development

Application of GIS in New Socialist Countryside Construction

Survey and research of new socialist countryside construction in Hebei Province are favorable for determining approaches and construction mode of new socialist countryside in other areas, and favorable for advancing the urban and rural integration in Hebei Province. With the aid of GIS technology, it is able to create spatial information database, correlate with rural statistical data and spatial information. Then, in the form of thematic map, it can visually indicate current situations of rural economy, and existing problems of development. Finally, it is expected to promote rural information construction and guide new countryside planning, to facilitate inquiry and search of information, and to provide supporting decisions for new socialist countryside construction

Effect of Ground Plane Deformation on Electrical Performance of Air Microstrip Antennas

This paper covers the variation of electrical performance of air microstrip antennas due to its ground plane deformation. A typical sinusoidal function is utilized to characterize the shape of deformation, based on which different shapes of ground plane can be obtained by changing control parameters. From the simulation results by HFSS, there is a strong linear relationship between the offset of resonant frequency and the amplitude of deformation. The equivalent thickness of the air medium is introduced into the calculation model, and then the mathematical model is established to describe the resonant frequency offset and deformation amplitude. It can also be seen from the radiation pattern that the directivity decreases with the increase of deformation. The proposed method can be used to predict the effect of ground plane deformation on electrical performance of air microstrip antennas