Silver spoon effects of hatching order in an asynchronous hatching bird

The silver spoon hypothesis proposes that individuals which develop under favourable conditions will gain fitness benefits throughout their lifetime. Hatching order may create a considerable size hierarchy within a brood and lead to earlier-hatched nestlings having a competitive advantage over their siblings, which has been illustrated in some studies. However, there have been few explorations into the effect on subsequent generations. Here, using a 15-year-long study, we investigated the long-term fitness consequence of hatching order in the endangered crested ibis, Nipponia nippon, a species with complete hatching asynchrony. In this study, we found strong support for silver spoon effects acting on hatching order. Compared to later-hatched nestlings, first-hatched nestlings begin reproduction at an earlier age, have higher adult survival rates, possess a longer breeding life span and achieve higher lifetime reproductive success. Interestingly, we found carry-over effects of hatching order into the next generation. Nestlings which hatched earlier and became breeders in turn also produced nestlings with larger tarsus and better body condition. Additionally, we found a positive correlation among life-history traits in crested ibis. Individuals which started reproduction at a younger age were shown to possess a longer breeding life span. And the annual brood size increased with an individual’s breeding life span. This suggests that the earlier-hatched nestlings are of better quality and the ‘silver spoon’ effects of hatching order cover all life-history stages and next generation effects

Identification of Chemical Components in Gannan Navel Orange Pulp by UPLC-QTOF-MS Coupled with HS-SPME-GC-MS

Using ultra-high performance liquid chromatography-quadrupole time-of-flight mass spectrometry (UPLC-QTOF-MS), we separated and identified 148 non-volatile organic compounds including flavonoids, organic acids and amino acids in navel orange pulp in 37 min. The volatile organic compounds (VOCs) in the pulp of navel oranges from four major production regions in southern Jiangxi Province, Ruijin, Xinfeng, Anyuan and Nankang were detected by headspace solid phase microextraction combined with gas chromatography-mass spectrometry (HS-SPME-GC-MS). In total, 97 VOCs were identified including esters, alcohols, aldehydes and terpenes. The results of this study provide detailed data for further research on chemical substances in the pulp of Gannan navel oranges

Three-dimensional niche partitioning between two colonially nesting ardeid species in central China

Abstract Background Interspecific competition is known to be strongest between those species that are both closely related and sympatric. Egrets are colonially nesting wetland birds that often overlap and can therefore be expected to compete in roosting and nesting habitat as well as in diet. According to the niche partitioning hypothesis, it is to be expected that these similar species would show differentiation in at least one of the main niche dimensions to reduce competition. We tested niche partitioning between the colonially nesting Little Egret (Egretta garzetta) and Cattle Egret (Bubulcus ibis) in temporal, spatial and trophic dimensions. Methods Field study was conducted in three mixed egret colonies in Yangxian County, southwest Shaanxi Province, central China. For each nest colony we recorded its spatial location, the height of nesting trees and of nests, the height of roosting trees and of roosting individuals within the trees. We determined the first egg-laying and first hatching dates of the two species. Craw dissection of storm-killed egret nestlings was used to measure the diet. Six transects were surveyed to study foraging habitat selection. Results We found that hatching time of Little Egrets peaked earlier (by about 1 month) than that of Cattle Egrets. Cattle Egrets nested and roosted higher than Little Egrets. The foraging habitats used by Little Egrets were dominated by river banks (73.49%), followed by paddy fields (13.25%) and reservoirs (10.84%), whereas Cattle Egret foraging sites were characterized by grasslands (44.44%), paddy fields (33.33%) and river banks (22.22%). Little Egrets consumed more fishes (65.66%) and Odonata larvae (13.69%) than Cattle Egrets, while Cattle Egrets were found feeding mainly on Coleoptera (29.69%) and Orthoptera (23.29%). Little Egrets preyed on larger mean biomasses of food items than Cattle Egrets. Conclusions Our results confirm the niche partitioning hypothesis as a mechanism for coexistence among ecologically similar species. In two coexisting egret species, niche partitioning is multidimensional, such that the two coexistent species occupy differing ecological space based on all three temporal, spatial and trophic niche dimensions

Wafer-level direct bonding of optimized superconducting NbN for 3D chip integration

3D integration has well-developed for traditional CMOS technology operating at room temperature, but few studies have been performed for cryogenic applications such as quantum computers. In this paper, a wafer-to-wafer bonding of superconductive joints based on niobium nitride (NbN) is performed to demonstrate the possibility of 3D integration of superconducting chips. The NbN thin films are deposited by magnetron sputtering. Its high critical temperature (15.2 K) is achieved by optimizing the sputtering recipe in terms of N2 flow rate and discharge voltage. Wafer-level bumping is bonded by the thermo-compression method. The sheet resistance of the thin film and the contact resistance of the joints are measured by the Greek-cross (4-point Kelvin method) and daisy chain structures at cryogenic temperature, respectively. Direct-bonding wafers with NbN superconductive joints avoid using adhesive layers and the bonding interface could still present superconducting electrical connections in a cryogenic environment above 4 K, which will allow us to use a smaller and high-cooling power cryostat. The contribution of this work could lead to the fabrication of multi-layered superconducting chip that operates beneficially in cryogenic temperature, which is essential in building scalable quantum processors.</p

Investigations into the unsteady internal flow characteristics for a waterjet propulsion system at different cruising speeds

Unsteady turbulent flows in a waterjet propulsion system are investigated at various cruising speeds with the emphasis on pressure fluctuations. The numerical methodology is based on the Reynolds-Averaged Navier-Stokes (RANS) equation with the SST k-omega turbulence model and a sliding mesh technique. The head and efficiency of the waterjet pump are predicted fairly well compared with the available experimental data. The pressure fluctuates intensively in the impeller and the dominant frequency is the impeller rotating frequency with the largest amplitude near the impeller inlet. Besides, two dominant frequency components exist in the intake duct and the diffuser. A high-frequency component is caused by the rotor-stator interaction, and another component is generated by the unsteady vortex evolution in the diffuser passage and would propagate upstream to the impeller and the intake duct. Analyses based on the vorticity transport equation demonstrate the great contribution of the vortex stretching term to the vorticity distribution and evolution in the diffuser. Finally, at the cruising speed of 45 knot, the flows inside the duct are strongly affected by the impeller rotation and present a periodic prewhirl motion with the dominant frequency of the impeller rotating frequency

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Lifetime breeding performance and breeding life-span of crested ibi

Tall trees drive the nest-site selection of wild Crested Ibis Nipponia nippon

Understanding how birds select breeding sites plays an important role in habitat protection, especially for the conservation of endangered species. With the increase in population size of the endangered Crested Ibis Nipponia nippon, its distribution range has expanded from mountain areas to plains located outside protected areas, representing a new challenge for conservation of the species. Identifying the current nesting habitat requirements is thus needed and can provide valuable information for the planning of new nature reserves. In this research, we surveyed a total of 117 nests across the whole distribution range from 2015 to 2019. We used generalized linear mixed-effects models to assess nesting preferences of the Crested Ibis in the wild. Results showed that in mountain areas, Masson pines Pinus massoniana were preferred (64.6%), whereas elms Ulmus pumila (44.9%) and aspens Populus davidiana (40.6%) were used more frequently lower down, probably because of their higher availability. In both mountain areas and plains the ibises selected tall nesting trees with larger diameter at breast height and preferred nesting rather high above ground, especially in plains where taller trees provided higher suitable nesting positions. The ibises also preferred nesting close to tree trunks, especially in mountain areas, probably for more safety from collapsing. Furthermore, in mountain areas, slope and distance to path had positive effects on nesting occurrence, and understorey coverage was avoided by nesting ibises, while these variables had little impact in plains. Our results indicate that, despite their range expansion, Crested Ibises rely on very specific habitat characteristics for nesting. We suggest relatively tall trees like elms and aspens should be preserved in plains. In addition, we highlight how selection patterns of Crested Ibises may vary, and that such variation should be addressed in conservation planning, especially in future reintroduction

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Breeding performance for each years of crested ibi

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Adult survival rate of crested ibi