Mg/Al dissimilar metals were joined together utilizing ultrasonic spot welding (USW) with a Zn interlayer. The interfacial layer forming, microstructure, mechanical properties and fracture mechanisms ...of the Mg/Zn/Al ultrasonic spot welded (USWed) joints were studied systematically. Results showed that four typical regions with different forming morphologies emerged in the interface owing to the uneven distribution of stress and temperature. These four regions were the vortex-like plastic deformation region on the outside of the sonotrode tip teeth, the thinner flat region directly under the sonotrode tip teeth, the network-like diffusion region inside of the sonotrode tip teeth, and the thicker flat region between the two sonotrode tip teeth. The interfacial layer of Mg/Zn/Al USWed joints was mainly composed of a Mg-Zn liquid phase layer of α-Mg + (α-Mg + MgZn) + MgZn2 + (Mg2Zn11 + β-Zn), a residual Zn interlayer, and a η-Zn + α-Al solid solution layer. The addition of Zn interlayer blocked the inter-diffusion of Mg and Al atoms successfully and avoided the generation of Mg-Al IMCs effectively. The formed Mg-Zn system structure and Zn-Al solid solution have relatively good performances and lower brittleness. In comparison, Mg/Al joints welded with a Zn interlayer in-between displayed the maximum shearing strength about 89.6% greater than those of joints without a Zn interlayer.
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•The key innovation points of the paper lay in the following aspects:(1) Existing studies focused on the microstructure and mechanical properties of joints, but there were few reports on the interfacial stress and temperature distribution during welding process in the field of Mg/Al ultrasonic spot welding (USW).•(2) In this paper, the evolutionary model was used to explain the microstructure characteristics of the Mg/Zn/Al USW joint interface and the microstructural transformation process of each region was described in terms of mechanism, which has been little studied in the related literatures so far.
Nutrition and weight gain during pregnancy can influence the life-course health of offspring. Clinical practice guidelines play an important role in ensuring appropriate nutrition and weight gain ...among pregnant women. This study aims to identify clinical practice guidelines on gestational weight gain and/or maternal nutrition across the Asia-Pacific region and to determine the quality of the guidelines and variability in the recommendations. Through a systematic search of grey literature from 38 Asia-Pacific countries, 23 published guidelines were obtained. Of these, 10 eligible clinical practice guidelines reporting nutrition- or/and weight-related recommendations for pregnant women were selected and reviewed. Guideline quality was determined using the Assessment of Guidelines for Research Evaluation II (AGREE II) instrument. Of the 10 guidelines, 90% were classified as low-quality in the AGREE II appraisal. Several variations were found with respect to recommendations on gestational weight gain, including those specific to Asian populations. The recommendations on dietary advice, additional energy intake, and nutritional supplementation during pregnancy were varied. Clinical practice guidelines on weight gain and nutrition in pregnancy across the Asia-Pacific region are generally of poor quality, reflecting significant variation, and need to be improved to ensure pregnant women receive appropriate advice. (PROSPERO registration no. CRD42021291395).
In this paper, a numerical model of hydrological and hydrodynamic processes—GAST model (GPU Accelerated Surface Water Flow and Associated Transport) is introduced to simulate the runoff control ...effect of rain garden based on a two-dimensional dynamic wave method. After validation with an experimental rain garden and a real rain garden in a sponge community, the results indicated a good agreement between simulated process of water growth and measured results. The RMSE values of 0.00084 and 0.1809 were less than half of the standard deviation of the simulated values, which showed that the model had a good performance and it was an ideal tool for the runoff control effect simulation in a single bioretention facility. Additionally, the results simulated by GAST model and SWMM model were compared with the measured results. For GAST model, the RMSE was 0.1809, and for SWMM model, the RMSE was 0.5226. It meant that GAST model had a higher accuracy in this test case. This model was also used to study the runoff control rules of rain garden at different return periods. The results showed that when the ponding depth was 15 cm and the flow area ratio was 15:1, the shorter the return period was, the greater the runoff-control rate was. The runoff-control rate of rain garden was 31.89%–100% for 0.5a to 50a. When the return period was shorter, the difference of the runoff-control rate was greater, and it was the opposite when the return period was longer. For example, the runoff-control rate was 53.02%–100% for the 0.5a to 5a inflow conditions, and the difference of the control rates between 1a and 2a was 25.79%, while the runoff-control rate for the return periods of 5a and 50a was 31.89%–53.02%, of which the difference between 10a and 20a control rates was only 4.30%.
In this work, a piezoresistive sensor structure based on carbon black (CB)@polyurethane (PU) yarn material was developed. Specifically, CB@PU yarn was constructed by the polymer-mediated water-based ...electrostatic deposition method. The distribution of the yarn was artificially controlled to fabricate conductive networks. The CB conductive layer was efficiently supported by the net-like structure of PU yarn, thus generating collaborative advantage. The as-fabricated pressure sensor not only displayed compressibility of over 97%, but also detected a wide pressure change from 25 Pa to 20 kPa. Furthermore, this sensor exhibited response time of less than 70 ms and reproducibility of over 10,000 cycles. The advantages of the CB@PU network ensured this pressure-sensitive structure enormous potential application in pressure sensitive equipment.
Abstract
The construction of low-impact development (LID) facilities has become an effective means to control urban waterlogging, but there is still a lack of scientific methods to achieve its ...accurate and reasonable planning and design. In this work, a high-precision hydrodynamic model was used to evaluate the construction effect of each LID facility scheme, and the fitted functional relationship was used to describe the law between the LID facility construction area and the construction effect. Finally, a genetic algorithm was used to automatically optimize the best LID facility construction scheme. Applying this method to the actual urban LID facility planning and construction, the optimal solution law is that the construction effect of single and combined LID facilities increases with the increase of construction cost. In the same low-cost construction scheme, the construction effect of combined LID facilities will be lower than that of single LID facilities, but with the continuous increase of construction cost, the construction effect of combined LID facilities will eventually be better than that of single LID facilities. According to this method, the decision-maker can get the optimal LID facility construction scheme to meet the actual engineering needs
Background
Among potential hosts, the rejection of foreign eggs, which is a common and effective strategy to counter brood parasitism, depends on egg recognition. Multimodal and multicomponent ...recognition cues of brood parasitic eggs, which include both tactile (size, shape, and texture) and visual (size, shape, color, and maculation) cues, are potentially involved in the perception and discrimination of foreign eggs by hosts. An egg rejection experiment on the host with different types of model eggs can help to accurately assess the relative contribution of different components on egg recognition and constraints to rejection, in which videos can help identify the method of host rejection.
Methods
Here, we assessed egg recognition and rejection responses by Oriental reed warblers (Acrocephalus orientalis), one of the most common hosts of common cuckoos (Cuculus canorus) which breed in eastern China. We designed six groups of model eggs for rejection experiments in which sensory cues included three grades of size and two categories of visual mimicry.
Results
Our experiments confirmed that the multimodal traits, which included variation in size, were significant predictors of egg rejection: We detected significantly higher rejection rates of mimetic spotted model eggs than of nonmimetic blue eggs. However, large model eggs did not yield higher rejection rates and, instead, these were less likely to be rejected and more likely to be deserted compared with smaller eggs. Further video‐recording data showed that there was no significant effect of egg size on the egg recognition rate (percentage of nests with evidence of egg pecking). No evidence that the egg appearance had an effect on the method of egg rejection (ejection or nest desertion) was found.
Conclusions
Only visual signals, such as color and maculation, contributed to the recognition of foreign eggs by Oriental reed warblers as recognizable clues, but not the egg size. The egg size had an impact on the type of egg rejection. It was less feasible for the warblers to eject large eggs and that is why they opted more often for desertion as the mean of model egg rejection. The significantly lower egg rejection rate of large eggs suggested that although some of them were recognized as foreign eggs, hosts failed to reject these eggs and finally the eggs were assumed to being accepted by the commonly used nest‐checking methods.
The relative contribution of egg size and appearance (color and maculation) on egg recognition and rejection of Oriental reed warblers were studied. We detected significantly higher rejection rates of mimetic spotted model eggs than of nonmimetic blue eggs. Large model eggs did not yield higher rejection rates, and instead, these were less likely to be rejected and more likely to be deserted compared with smaller eggs.
For migratory birds that specialize on particular benthic macroinvertebrate species, the timing of migration is critical since prey availability may be temporally limited and a function of local ...ambient temperature. Hence, variation in local ambient temperature can influence the diet composition of migrant birds, and, consequently, they may be constrained by which stopover and wintering sites they are able to utilize during periods of colder temperatures. Here, we use fecal analysis, observer‐based population counts, digital video recordings, and temperature data to test five predictions regarding the influence of local ambient temperature on the activity and availability of mudflat crabs—a key prey resource at three staging/wintering sites in eastern China, for migratory Red‐crowned cranes (Grus japonensis) and how this subsequently influences crane diet and use of wetland sites. Pearson's correlations and generalized linear models revealed that mudflat crabs became significantly more surface active with increasing burrow ambient temperature. Piecewise regression analysis revealed that crab surface activity was largely limited to a burrow ambient temperature threshold between 12 and 13℃ after which activity significantly increased. Crab activity declining temporally during the crane's autumn migration period but increased during spring migration. Crabs accounted for a significant proportion of crane diet at two of three sites; however, the frequency of crab remains was significantly different between sites, and between autumn and spring migration. Analyses of crane count data revealed a degree of congruence between the migration timing of Red‐crowned cranes with periods of warmer ambient temperature, and a significant, positive correlation between the percentage of crab remains in crane feces and site ambient temperature. Collectively, our data suggest that temperature‐related mudflat crab activity may provide an important time window for migratory Red‐crowned cranes to utilize critical stopover sites and the crabs’ food resources.
Mudflat crabs became significantly more surface active with increasing burrow ambient temperature, and the crab surface activity was largely limited to a burrow ambient temperature threshold between 12 and 13°C after which activity significantly increased. Crabs accounted for a significant proportion of crane diet at two of three sites; however, the frequency of crab remains was significant different between sites, and between autumn and spring migration. A degree of congruence between the migration timing of Red‐crowned cranes with periods of warmer ambient temperature, and a significant, positive correlation between the percentage of crab remains in crane feces and site ambient temperature.
Suaeda salsa saltmarshes are an important coastal wetland habitat of China’s northern Yellow Sea, which plays a critical role in sequestering carbon (blue carbon), protecting shorelines, maintaining ...biodiversity, and has substantial economic value (e.g., ecotourism). However, the area of S. salsa has been rapidly declining due to several different threats from reclamation and invasive species that impact its natural succession. Here, we map the changes in the distribution of the S. salsa saltmarshes along the northern Yellow Sea of China (NYSC) at 5-year intervals by applying the supervised maximum likelihood method to analyze Landsat images from 1988 to 2018 and investigate the potential impact of three important factors on habitat change by analyzing the temporal changes in S. salsa saltmarshes with other land covers. S. salsa saltmarsh areas have decreased by 63% (264 km2 ha to 99 km2), and the average loss of S. salsa saltmarshes was 5.5 km2/year along the NYSC over the past three decades. There have been many dramatic declines in the two main distribution areas of S. salsa saltmarshes with a 77% loss of habitat area in Liaodong Bay (from 112 km2 to 26 km2) and a 52% loss in the Yellow River Delta wetland-Guangli-Zhima estuarine wetland (from 137 km2 to 65 km2). Land reclamation is the most important impact factor in the loss of S. salsa saltmarshes, while there have been limited effects of natural succession and smooth cordgrass (Spartina alterniflora) invasion. In light of the important ecological services and economic value of the S. salsa habitat, emergency conservation actions (e.g., habitat restoration, strictly supervision) are needed to limit the rapid habitat loss, which should include the immediate cessation of extensive land reclamation along the NYSC.
Abstract
Objectives
To identify age-related radiographic risk factors for degenerative lumbar spinal stenosis (DLSS) and analyze correlations among them.
Methods
A total of 180 cases were enrolled in ...this study, and lumbar magnetic resonance was performed. Among them, 93 cases suffered DLSS and lumbar dynamic X-ray was examined. And following parameters were measured and evaluated: intervertebral disk height (IDH), the ratio of IDH(IDH
L4-5/L3-4
), initial IDH of L4-5(iIDH
L4-5
) in the DLSS group, disk degeneration (DD), cartilaginous endplate failure (CEF), Modic changes, the thickness of ligamentum flavum (LF), range of intervertebral motion (ROM), facet joint opening (FJO), facet joint angle (FJA), the standard cross-sectional area (SCSA) of the multifidus, erector spinae, and psoas major muscles. The data of two groups were compared, and the possible risk factors of DLSS were analyzed.
Results
Compared with the control group, the DLSS group had higher IDH except for L4-5 and larger iIDH
L4-5
(
P
< 0.05). Significant differences were shown in CEF and the thickness of LF at L1-S1 and DD at L4-5 (
P
< 0.05). The DLSS group had smaller SCSA of multifidus, erector spinae, and psoas major muscles but greater FJA, FJO (
P
< 0.05). And the risk of DLSS increased when iIDH
L4-5
≥ 10.73 mm, FJA ≥ 52.03° , or FJO ≥ 3.75 mm. IDH positively correlated with SCSA of multifidus and psoas major muscles and ROM at L1-S1 (
P
< 0.05). DD showed negative linear relations with SCSA of multifidus and psoas muscle and positive linear relation with CEF at L1-2, L2-3, and L5-S1 (
P
< 0.05).
Conclusion
Larger initial disk height and excessive CEF may induce DLSS by increasing intervertebral mobility to promote DD, and atrophied paravertebral muscles by weakening the stability of lumbar spine.
Protected areas provide essential habitats for wildlife by conserving natural and semi‐natural habitats and reducing human disturbance. However, whether breeding birds vulnerable to nest predation ...can benefit from strict land management in the protected area is unclear. Here, we compare the nesting performance of two groups of a ground‐nesting shorebird, the Kentish plover (Charadrius alexandrinus), in the protected area (Liaohekou Natural Reserve, hereinafter PA), and the control non‐protected area (non‐PA) around the Liaohekou Natural Reserve, in the north of the Yellow Sea, China, and identify which environmental factors, such as nesting habitat and nest materials, influence the daily nest survival rate (DSR). We found similar nesting habitats in both study areas, dominated by bare land or Suaeda salsa grassland. However, DSR was lower in PA (0.91 ± 0.01) than in non‐PA (0.97 ± 0.01). Kentish plovers nesting in areas with vegetation cover experienced lower DSR than in bare lands in both areas, and nests built with materials of S. salsa sticks had the lowest DSR in the bare land. Data from infrared cameras confirmed relatively higher predator abundances and nest predation rates by nocturnal mammals, such as Eurasian badgers (Meles meles), in PA than in non‐PA, and this pattern was especially evident for plover nests located in S. salsa grassland. Our results suggest that Liaohekou Natural Reserve protected area may not necessarily provide safe nesting sites for Kentish plovers due to the abundance of generalist mammal nest predators. However, the PA includes about 80% of the nests from both locations. This means the contribution of the total number of successful nests continues to be much higher within PA, with the benefit for the species that this brings in terms of conservation. The variation and mechanisms underlying differences in the nest predator communities of PA and non‐PA deserve further study.
The daily nest survival rate of Kentish plover nesting within the protected areas was lower than that outside the protected areas. Kentish plovers nesting in areas with vegetation cover dominated by Suaeda salsa experienced lower DSR than in bare lands. Higher predator densities of nocturnal mammals in the protected areas increased the nest predation rate of Kentish plovers.
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