Geographic patterns of taxonomic and phylogenetic β-diversity of aquatic angiosperms in China

China covers a vast territory harbouring a large number of aquatic plants.Although there are many studies on the β-diversity of total,herbaceous or woody plants in China and elsewhere,few studies have focused on aquatic plants.Here,we analyse a comprehensive data set of 889 aquatic angiosperm species in China,and explore the geographic patterns and climatic correlates of total taxonomic and phylogeneticβ-diversity as well as their turnover and nestedness components.Our results show that geographic patterns of taxonomic and phylogenetic β-diversity are highly congruent for aquatic angiosperms,and taxonomic β-diversity is consistently higher than phylogenetic β-diversity.The ratio between the nestedness component and total β-diversity is high in northwestern China and low in southeastern China.The geographic patterns of taxonomic and phylogenetic β-diversity of aquatic angiosperms in China are obviously affected by geographic and climatic distances,respectively.In conclusion,the geographic patterns of taxonomic and phylogenetic β-diversity of aquatic angiosperms are consistent across China.Climatic and geographic distances jointly affect the geographic patterns of β-diversity of aquatic angiosperms.Overall,our work provides insight into understanding the large-scale patterns of aquatic angiosperm β-diversity,and is a critical addition to previous studies on the macroecological patterns of terrestrial organisms.

Effects of secondary phases on texture and mechanical properties of as-extruded Mg-Zn-Er alloys

The effects of kinds of secondary phases on texture and mechanical properties of Mg-Zn-Er alloys were investigated. The results suggest that the I-phase has a great effect on modification of the texture via the discontinuous dynamic recrystallization mechanism（DDRX）, which tends to form well-developed equiaxed recrystallized grains. Meanwhile, the W-phase plays an important role in refining the grain size via continuous dynamic recrystallization（CDRX）, companied with a higher maximum texture intensity. Thus, the Mg-6Zn-1 Er alloy containing I-phase shows a performance of higher elongation of 20.4%. The Mg-2Zn-2Er alloy including W-phase displays a better tensile strength, and the yield strength（YS） is about 247 MPa.

Morphological and genomic evidence for a new species of Corallorhiza(Orchidaceae:Epidendroideae)from SW China

Corallorhiza sinensis,a new species of mycoheterotrophic orchid from western Sichuan,China,is described and illustrated based on molecular and morphological evidence.It is morphologically similar to Corallorhiza trifida,but can be distinguished by bigger flowers,both sepals and petals with 3 veins,and longer lateral lobes of lip.To distinguish the new Corallorhiza species and explore its phylogenetic position within subtribe Calypsoinae,this study employed sequences of the nuclear ribosomal DNA(nrDNA)and whole plastome assembled from the genome skimming approach.The plastome is 148,124 bp in length,including a pair of inverted repeats(IRs)of 26,165 bp,a large single-copy region(LSC)of 82,207 bp,and a small single-copy region(SSC)of 13,587 bp.Further,phylogenetic analyses were performed using nrDNA sequence and 79 coding sequences(CDSs)from 26 complete plastomes of subtribe Calypsoinae.The phylogenetic tree based on nrDNA sequence suggested that Corallorhiza is a monophyletic group,and strongly support C.sinensis as sister to the rest species of Corallorhiza.The plastid tree showed that 10 Corallorhiza species grouped into two clades and C.sinensis is most closely related to the North American C.striata and C.bentleyi instead of Oreorchis foliosa and O.angustata in the same clade.The plastid tree and nrDNA tree indicate Oreorchis is a paraphyletic.Although the topological conflicts are displayed between plastome and nrDNA phylogenies of C.sinensis,it is still the most closely related to Corallorhiza.Comparative analysis showed that C.sinensis populations are characteristic of the intermediate morphological traits between Corallorhiza and Oreorchis.The finding of this new species from China shed new light on the phylogeny of Oreorchis and Corallorhiza.

Modeling impacts of climate change on the potential distribution of six endemic baobab species in Madagascar

Madagascar,a globally renowned biodiversity hotspot characterized by high rates of endemism,is one of the few remaining refugia for many plants and animal species.However,global climate change has greatly affected the natural ecosystem and endemic species living in Madagascar,and will likely continue to influence species distribution in the future.Madagascar is home to six endemic baobab(Adansonia spp.,Bombacoideae[Malvaceae])species(Adansonia grandidieri,A.suarezensis,A.madagascariensis,A.perrieri,A.rubrostipa,A.za),which are remarkable and endangered plants.This study aimed to model the current distribution of suitable habitat for each baobab species endemic to Madagascar and determine the effect that climate change will have on suitable baobab habitat by the years 2050 and 2070.The distribution was modeled using MaxEnt based on locality information of 245 occurrence sites of six species from both online database and our own field work.A total of seven climatic variables were used for the modeling process.The present distribution of all six Madagascar's baobabs was largely influenced by temperature-related factors.Although both expansion and contraction of suitable habitat are predicted for all species,loss of original suitable habitat is predicted to be extensive.For the most widespread Madagascar baobab,A.za,more than 40%of its original habitat is predicted to be lost because of climate change.Based on these findings,we recommend that areas predicted to contract in response to climate change should be designated key protection regions for baobab conservation.

Traditional knowledge, use and conservation of plants by the communities of Tharaka-Nithi County, Kenya

Rural communities in Kenya largely depend on plant resources for their livelihood.The utilization of these resources depends on the availability of plant resources and the level of knowledge of the residents.We conducted an ethnobotanical study in Tharaka-Nithi County in Kenya to determine the knowledge and utilization of various plant species by the local communities.The study was conducted in four major administrative regions from June 2018 to February 2019,involving interview schedules using semi-structured open-ended questionnaires and guided field collections with 48 informants.A total of 214 plant species distributed in 73 families and 169 genera with 616 Use Reports(URs)were documented.Fabaceae was the highest family cited by the informants(31 species)followed by Lamiaceae and Euphorbiaceae(each with 11 species).Trees(49%)and shrubs(32%)were the top life forms of the plants frequently utilized by the local residents.The general plant uses reported were medicinal,food,fodder,construction,fuel,pesticidal,religious,live fencing,and making crafts.Zanthoxylum gilletii,Prunus africana,and Solanum incanum were found to be highly valued by the local communities.Plant utilization as food and medicinal uses against snake-bite related problems had the highest Informant Consensus Factor(ICF).Only 29(13.6%)of the species reported had their status assessed by the International Union for Conservation of Nature(IUCN).Conservation measures,alongside awareness creation in this region,are highly recommended for the species endemic to the region,highly depended on by the community,and those threatened according to IUCN standards.

Pollinator diversity benefits natural and agricultural ecosystems,environmental health,and human welfare

Biodiversity loss during the Anthropocene is a serious ecological challenge.Pollinators are important vectors that provide multiple essential ecosystem services but are declining rapidly in this changing world.However,several studies have argued that a high abundance of managed bee pollinators,such as honeybees(Apis mellifera),may be sufficient to provide pollination services for crop productivity,and sociological studies indicate that the majority of farmers worldwide do not recognize the contribution of wild pollinator diversity to agricultural yield.Here,we review the importance of pollinator diversity in natural and agricultural ecosystems that may be thwarted by the increase in abundance of managed pollinators such as honeybees.We also emphasize the additional roles diverse pollinator communities play in environmental safety,culture,and aesthetics.Research indicates that in natural ecosystems,pollinator diversity enhances pollination during environmental and climatic perturbations,thus alleviating pollen limitation.In agricultural ecosystems,pollinator diversity increases the quality and quantity of crop yield.Furthermore,studies indicate that many pollinator groups are useful in monitoring environmental pollution,aid in pest and disease control,and provide cultural and aesthetic value.During the uncertainties that may accompany rapid environmental changes in the Anthropocene,the conservation of pollinator diversity must expand beyond bee conservation.Similarly,the value of pollinator diversity maintenance extends beyond the provision of pollination services.Accordingly,conservation of pollinator diversity requires an interdisciplinary approach with contributions from environmentalists,taxonomists,and social scientists,including artists,who can shape opinions and behavior.

The therapeutic mechanism of black soybean in atherosclerosis based on network pharmacology

Objective:To investigate the cardiovascular mechanism of black soybean,the biological characteristics of black soybean were studied by bioinformatics,and the mechanism of its treatment for atherosclerosis was further determined.Methods:Firstly,the basic data sets of effective components and corresponding targets of black beans were constructed,and then mapped to the AS background network obtained from DisGeNET database and CTD database.Finally,the potential targets of black beans acting on AS were obtained.After constructing the protein-protein interaction(PPI)network,the topological characteristics of these targets were analyzed.KEGG and GO were enriched to obtain the potential mechanism of black soybean acting on AS.Results:There were 12 bioactive components reported in black soybean.Among them,beta-sitosterol,stigmasterol and N-(4-hydroxyphenylethyl)ACTINIDINE were the three most active components.There are 19 targets of black soybeans acting on PPI network of AS disease.Among them,ADRB2 and PTGS2 are important targets for black soybeans to alleviate AS.The therapeutic pathways include arachidonic acid metabolism and serotonin synapse.Conclusion:Black soybean can play a therapeutic role in AS through multi-target and multi-pathway.The application of network pharmacology can quickly clarify the characteristics of functional foods and identify their potential targets and mechanisms for disease treatment.

Non-climate environmental factors matter to Holocene dynamics of soil organic carbon and nitrogen in an alpine permafrost wetland,Qinghai‒Tibet Plateau

Studies on the responses of soil organic carbon(SOC)and nitrogen dynamics to Holocene climate and environment in permafrost peatlands and/or wetlands might serve as analogues for future scenarios,and they can help predict the fate of the frozen SOC and nitrogen under a warming climate.To date,little is known about these issues on the Qinghai‒Tibet Plateau(QTP).Here,we investigated the accumulations of SOC and nitrogen in a permafrost wetland on the northeastern QTP,and analyzed their links with Holocene climatic and environmental changes.In order to do so,we studied grain size,soil organic matter,SOC,and nitrogen contents,bulk density,geochemical parameters,and the accelerator mass spectrometry(AMS)^(14)C dating of the 216-cm-deep wetland profile.SOC and nitrogen contents revealed a general uptrend over last 7300 years.SOC stocks for depths of 0-100 and 0-200 cm were 50.1 and 79.0 kgC m^(-2),respectively,and nitrogen stocks for the same depths were 4.3 and 6.6 kgN m^(-2),respectively.Overall,a cooling and drying trend for regional climate over last 7300 years was inferred from the declining chemical weathering and humidity index.Meanwhile,SOC and nitrogen accumulated rapidly in 1110e720 BP,while apparent accumulation rates of SOC and nitrogen were much lower during the other periods of the last 7300 years.Consequently,we proposed a probable conceptual framework for the concordant development of syngenetic permafrost and SOC and nitrogen accumulations in alpine permafrost wetlands.This indicates that,apart from controls of climate,non-climate environmental factors,such as dust deposition and site hydrology,matter to SOC and nitrogen accumulations in permafrost wetlands.We emphasized that environmental changes driven by climate change have important impacts on SOC and nitrogen accumulations in alpine permafrost wetlands.This study could provide data support for regional and global estimates of SOC and nitrogen pools and for global models on carbon‒climate interactions that take into account of alpine permafrost wetlands on the northeastern QTP at mid-latitudes.

Effect of welding heat input on microstructure and impact toughness in CGHAZ of X100Q steel

The coarse-grained heat-affected zones (CGHAZs) of X100Q steel were reproduced via simulating their welding thermal cycles with the varying heat input (Ef) from 10 to 55 kJ/cm in Gleeble3500 system. The microstructures were characterized, and the impact toughness was estimated from each simulated sample. The results indicate that the microstructure in each simulated CGHAZ was primarily constituted of lath-like bainite. With the decreased heat input and accordingly the lowered Ar3 (the onset temperature for this transition), the prior austenite grain and the bainitic packet/block/lath substructure were refined remarkably, and the impact toughness was enhanced due to the microstructure refinement. The bainitic packet was the microstructural unit most effectively controlling the impact properties in CGHAZ of X100Q steel, due to their close correlation with the 50% fracture appearance transition temperatures, their size equivalent to the cleavage facet and their boundaries impeding the crack propagation.

Distributed fault-tolerant strategy for electric swing system of hybrid excavators under communication errors

A distributed fault-tolerant strategy for the controller area network based electric swing system of hybrid excavators is proposed to achieve good performance under communication errors based on the adaptive compensation of the delays and packet dropouts. The adverse impacts of communication errors are effectively reduced by a novel delay compensation scheme, where the feedback signal and the control command are compensated in each control period in the central controller and the swing motor driver, respectively, without requiring additional network bandwidth. The recursive least-squares algorithm with forgetting factor algorithm is employed to identify the time-varying model parameters due to pose variation, and a reverse correction law is embedded into the feedback compensation in consecutive packet dropout scenarios to overcome the impacts of the model error. Simulations and practical experiments are conducted. The results show that the proposed fault-tolerant strategy can effectively reduce the communication-error-induced overshoot and response time variation.

Phylogeography of Haplocarpha rueppelii(Asteraceae) suggests a potential geographic barrier for plant dispersal and gene flow in East Africa

East Africa is a biodiversity hotspot. Haplocarpha rueppelii （Sch.Bip.） Beauverd is mainly distributed in the alpine grassland of East Africa. Here we sampled 65 individuals of eight populations/locations of H. rueppelii including hairy and glabrous forms from Mts. Elgon, Aberdare, Kenya, Kilimanjaro and Bale Mountains. We then sequenced one nuclear and three chloroplast DNA fragments and conducted phylogeographic analyses to test the taxonomic rank of the two forms and causes for the differentiation （intrinsic reproductive isolation and geographic barrier）. The results demonstrate that the species consists of two major groups, one includes the populations from Mts. Elgon, Aberdare and Bale, while the other includes Mts. Kenya and Kilimanjaro. The species has established in Mts. Kenya and Aberdare during the Pleistocene. However, migration rate for individuals between the two mountains was low as showed by gene flow analysis. A barrier for plant dispersal and gene flow would have existed between Mts. Aberdare and Kenya since at least Pleistocene. No change of the taxonomic concept of this species is needed. This study reveals a potential geographic barrier in East Africa. We hope it will arouse more scientists＇ interests in phylogeography and biodiversity of East Africa.

Effect of increased nitrogen content on continuous cooling transition of γ→α in hot-deformed low-C Mo-V-Ti steels

The two-stage controlled rolling and cooling at 0.5-50℃/s of low-carbon Mo-V-Ti steels with the increasing nitrogen content from 0.0032 to 0.0081 and 0.0123 wt.% were simulated through a Gleeble 3500 system. The continuous cooling transition (CCT) of γ→α in each steel was estimated via microstructure characterization and CCT diagram. The results indicated that CCT diagram for each steel was divided into three regions of γ→ferrite,γ→pearlite and γ→ bainite, and the increasing N content elevated all the starting temperatures for γ→α. Consequently, the polygonal ferrite (PF) and pearlite formed in each steel cooled at 1℃/s and, however, the increasing N content led to slightly coarser ferrite grain and pearlite colony. With the increased cooling rate to 10 and 30℃/s, a mixed microstructure of acicular ferrite (AF), granular bainite (GB) and lath bainite (LB) formed in 32N steel and in contrast, the mixture of PF+AF+GB in 8IN and 123N steels. The increasing N content promoted (Ti,V)(C,N) precipitation, enhanced the intragranular PF/AF nucleation, increased martensite/austenite constituent and depressed LB. In addition, the mechanisms dominating the effect of increasing N on this CCT of γ→α were discussed.

Optimization design of an interior permanent-magnet synchronous machine for a hybrid hydraulic excavator

A hybrid power transmission system （HPTS） is a promising way to save energy in a hydraulic excavator and the electric machine is one of the key components of the system. In this paper, a design process for permanent-magnet synchronous machines （PMSMs） in a hybrid hydraulic excavator （HHE） is presented based on the analysis of the working conditions and requirements of an HHE. A parameterized design approach, which combines the analytical model and the 2D finite element method （FEM）, is applied to the electric machine to improve the design efficiency and accuracy. The analytical model is employed to optimize the electric machine efficiency and obtain the statordimension and flux density distribution. The rotor is designed with the FEM to satisfy the flux requirements obtained in stator design. The rotor configuration of the PMSM employs an interior magnet structure, thus resulting in some inverse saliency, which allows for much higher values in magnetic flux density. To reduce the rotor leakage, a disconnected type silicon steel block structure is adopted. To improve the air gap flux density distribution, the trapezoid permanent magnet （PM） and centrifugal rotor structure are applied to PMSM. Demagnetization and armature reactions are also taken into consideration and calculated by the FEM. A prototype of the newly designed electric machine has been fabri- cated and tested on the experimental platform. The analytical design results are validated by measurements.

基于强化学习的混合动力挖掘机实时能量管理控制器设计（英文）

目的:混合动力挖掘机的能量管理策略直接影响着系统的燃油经济性。本文旨在通过研究混合动力挖掘机能量管理系统,得到最优能量管理策略,并开发实时能量管理控制器,降低系统的燃油消耗。创新点:1.通过强化学习算法,设计时间无关的实时能量管理控制器;2.通过极大值原理求得最优能量管理问题的解析解,并用来辅助实时能量管理控制器设计。方法:1.建立负载的马尔科夫模型,运用强化学习算法,得到实时能量管理控制器;2.运用极大值原理,求得最优能量管理问题的解析解,并将其作为初始能量管理策略;3.通过仿真模拟和实验研究,验证所设计的实时能量控制器的性能。结论:1.基于强化学习的能量管理控制器是一个可以在线应用的与时间无关的实时能量管理控制器;2.基于强化学习的能量管理控制器优于广泛使用的恒温控制器和等效消耗最小化策略控制器;3.基于强化学习的能量管理控制器由于其闭环特性可适用于不同类型的作业工况。