The mid-domain effect in flowering phenology

The timing of flowering is an important driver of species distribution and community assembly patterns.However,we still have much to learn about the factors that shape flowering diversity(i.e.,number of species flowering per period) in plant communities.One potential explanation of flowering diversity is the mid-domain effect,which states that geometric constraints on species ranges within a bounded domain(space or time) will yield a mid-domain peak in diversity regardless of ecological factors.Here,we determine whether the mid-domain effect explains peak flowering time(i.e.,when most species of communities are flowering) across China.We used phenological data of 16,267 herbaceous and woody species from the provincial Flora in China and species distribution data from the Chinese Vascular Plant Distribution Database to determine relationships between the observed number of species flowering and the number of species flowering as predicted by the mid-domain effect model,as well as between three climatic variables(mean minimum monthly temperature,mean monthly precipitation,and mean monthly sunshine duration).We found that the mid-domain effect explained a significant proportion of the temporal variation in flowering diversity across all species in China.Further,the mid-domain effect explained a greater proportion of variance in flowering diversity at higher latitudes than at lower latitudes.The patterns of flowering diversity for both herbaceous and woody species were related to both the mid-domain effect and environmental variables.Our findings indicate that including geometric constraints in conjunction with abiotic and biotic predictors will improve predictions of flowering diversity patterns.

Evaluating the relative importance of predictors in Generalized Additive Models using the gam.hp R package

Generalized Additive Models(GAMs)are widely employed in ecological research,serving as a powerful tool for ecologists to explore complex nonlinear relationships between a response variable and predictors.Nevertheless,evaluating the relative importance of predictors with concurvity(analogous to collinearity)on response variables in GAMs remains a challenge.To address this challenge,we developed an R package named gam.hp.gam.hp calculates individual R^(2) values for predictors,based on the concept of'average shared variance',a method previously introduced for multiple regression and canonical analyses.Through these individual R^(2)s,which add up to the overall R^(2),researchers can evaluate the relative importance of each predictor within GAMs.We illustrate the utility of the gam.hp package by evaluating the relative importance of emission sources and meteorological factors in explaining ozone concentration variability in air quality data from London,UK.We believe that the gam.hp package will improve the interpretation of results obtained from GAMs.

Recent advancements in surface plasmon polaritons-plasmonics subwavelength structures in microwave and terahertz regimes

This paper presents a review of recent investigational studies on exciting Surface Plasmon Polaritous (SPPs)in MicroWave (MW)and TeraHertZ (THz)regimes by using subwavelength corrugated patterns on conductive or metal surfaces.This article also describes SPP Microstrip (MS)structures at microwave and terahertz frequencies, and compares their significance with that of conventional MS Transmission Lines (TL),in order to tackle the key challenges of high gain,bandwidth size,compactness,TL losses,and signal integrity in high-end electronic de- vices.Because they have subwavelength properties,surface plasmon polaritous are gaining attention for their improved performance and ability for miniaturization in high-speed dense circuits.They possess comparably minuscule wavelength compared to incident light (photons).Consequently,they can demonstrate stronger spatial confinement and higher local field intensity at optical frequencies.In addition to engineering spoof SPP waveguides,which are created by engraving grooves and slits on metal surfaces to allow operation on at low frequencies (microwave and terahertz),semiconductors with smaller permittivity values and thus lower free charge carrier concentration have been demonstrated as a potential candidate in plasmonic devices.If necessary,further tuning of semiconductor-based SPP structures is aided by controlling the charge carrier concentration through doping,or by external stimuli such as optical illumination or thermal excitation of charge carriers from valence to conduction bands.This article conclusively covers previously elucidated perspectives on manipulating SSPPs in the MW and THz ranges,and emphasizes how these could steer next-generation plasmonic devices.

Electromagnetic spectrum chipless radio frequency identification:A review

Over the past few years,Radio Frequency IDentification(RFID)has stridden significantly due to its adoption in many business and daily life activities.RFID empowers end-to-end and item-by-item visibility,letting the customers or decision-makers effectively trail the personnel and resources for improved management.Significant research and development in this area have transformed the inexpensive,miniaturized technology of RFIDs without chip inside.Chipless Radio Frequency IDentification(CRFID)is a unique wireless technology based on radar principle to sense,identify,and track the objects.CRFIDs are simplified and miniaturized tags of traditional RFID,which can widely be used in small and cheap objects/applications in our daily life.This paper reviews the definition,principle,and most recent development in CRFIDs.Based on the reported researches,the ElectroMagnetic Spectrum(EMS)method is typical,which has been concerned by many RFID researchers.Therefore,this paper reviews different types of EMS CRFID tag and classifies these tags based on structure design emphasizing their significant geometries in comparison with performance parameters.Antenna and coding methods of the EMS CRFID are also elaborated,contrasting the tag capacity and coding performance.Finally,we briefly summarize the challenges and limitations in this emerging field and look forward to the prospects of future CRFID.

More endemic birds occur in regions with stable climate, more plant species and high altitudinal range in China

Background:Geographical distribution of endemic species and its multiple scale drivers are an important topic in biodiversity conservation,because these species are especially vulnerable to climate change and habitat degradation,and therefore have high conservation priority.Here,for the first time,we simultaneously linked glacial-interglacial climate change,contemporary climate,plant species richness and altitudinal range with endemic bird distribution in China.Methods:Ordinary least squares models and simultaneous autoregressive models were used to assess the associations between endemic bird richness,endemic bird ratio and each explanatory variable.Structural Equation Models were also performed to test the direct and indirect effects of these variables on endemic bird richness and endemic bird ratio.Results:Higher endemic bird richness and endemic bird ratio occurred in regions with stable glacial-interglacial temperature,i.e.,southwest China.Plant species richness and altitudinal range were also positively correlated with endemic bird richness and endemic bird ratio.Glacial-interglacial temperature change,contemporary precipitation,plant species richness and altitudinal range were all included in the best combination of variables for endemic bird richness.Importantly,glacial-interglacial temperature change had strong direct effects on both endemic bird richness and endemic bird ratio,while plant species richness only had a direct effect on endemic bird richness.Conclusions:Our results indicate that endemic birds in China concentrate in southwest regions where there are stable glacial-interglacial temperature,more plant species and larger altitudinal range.Notably,while stable climate has strong direct effects on both endemic bird richness and endemic bird ratio,plant species may affect endemic bird richness through its effect on overall bird species richness.Importantly,the recent anthropogenic activities have also significantly intensified in this region,which would pose huge challenge for biodiversity conservation in China.

glmm.hp包对零膨胀广义线性混合模型与多元回归的扩展

glmm.hp是一个专为评估广义线性混合模型(GLMMs)中共线预测变量的相对重要性而开发的R包。自从其于2022年1月发布以来,已迅速在生态学界获得认可和流行。然而,先前的glmm.hp包仅限于处理仅来源于lme4和nlme包的GLMMs。最新的glmm.hp包增加了新功能。首先,它整合了从glmmTMB包获得的结果,使其能够有效地处理零膨胀广义线性混合模型。此外,最新的glmm.hp包添加了基于原始R2和校正R2的普通多元回归的共性分析和层次分割的功能。本文将展示这些新功能,更方便广大的研究人员使用。

R在林业研究中的应用

R是用于数据分析、建模和可视化的强大编程语言之一,广泛运用于各个科学学科,但其林学研究领域受欢迎程度还尚待探索。为了回答这个问题,我们对8种主要林学期刊上2013至2022年间发表的14800多篇研究文章R和R包的使用频率进行了全面分析。分析结果显示,有6700篇文章(占总数的45.7%)明确使用R进行数据分析。R的使用率呈现出持续增长的趋势,从2013年的28.3%上升到2022年的60.9%。使用最多的5个R软件包包括vegan、lme4、nlme、MuMIn和ggplot2。各期刊的关注点有所不同导致R软件包使用频率格局不同。该分析表明,R语言凭借其强大的统计和数据可视化功能,在林学各个领域具有广阔的使用前景。

Generating Markov Logic Networks Rulebase Based on Probabilistic Latent Semantics Analysis

Human Activity Recognition(HAR)has become a subject of concern and plays an important role in daily life.HAR uses sensor devices to collect user behavior data,obtain human activity information and identify them.Markov Logic Networks(MLN)are widely used in HAR as an effective combination of knowledge and data.MLN can solve the problems of complexity and uncertainty,and has good knowledge expression ability.However,MLN structure learning is relatively weak and requires a lot of computing and storage resources.Essentially,the MLN structure is derived from sensor data in the current scene.Assuming that the sensor data can be effectively sliced and the sliced data can be converted into semantic rules,MLN structure can be obtained.To this end,we propose a rulebase building scheme based on probabilistic latent semantic analysis to provide a semantic rulebase for MLN learning.Such a rulebase can reduce the time required for MLN structure learning.We apply the rulebase building scheme to single-person indoor activity recognition and prove that the scheme can effectively reduce the MLN learning time.In addition,we evaluate the parameters of the rulebase building scheme to check its stability.

glmm.hp:一个计算广义线性混合模型中单个预测变量效应的R包

广义线性混合效应模型(GLMMs)是当代生态学研究中广泛应用的数据分析模型。然而,确定GLMMs中共线性的预测变量(固定效应)对响应变量的相对重要性是个挑战。基于适用于多元分析的‘平均共享方差’的算法,我们开发一个新的R包glmm.hp来分解GLMMs中由固定效应解释的边际(marginal)R2^(2)。我们论述了该软件包的工作原理并通过模拟数据集演示了该软件包的使用。glmm.hp包的输出结果为每个预测变量将获得一个独自的(individual)边际R2^(2),且它们的总和刚好等于模型总的边际R2^(2)。总之,我们相信glmm.hp包将有助于解释GLMMs的输出结果。

The Genomes of the Allohexaploid Echinochloa crus-galli and Its Progenitors Provide Insights into Polyploidization-Driven Adaptation

The hexaploid species Echinochloa crus-galli is one of the most detrimental weeds in crop fields,especially in rice paddies.Its evolutionary history is similar to that of bread wheat,arising through polyploidization after hybridization between a tetraploid and a diploid species.In this study,we generated and analyzed high-quality genome sequences of diploid(E.haploclada),tetraploid(E.oryzicola),and hexaploid(E.crus-galli)Echinochloa species.Gene family analysis showed a significant loss of disease-resistance genes such as those encoding NB-ARC domain-containing proteins during Echinochloa polyploidization,contrary to their significant expansionduring wheat polyploidization,suggesting that natural selection might favor reduced investment in resistance in this weed to maximize its growth and reproduction.In contrast to the asymmetric patterns of genome evolution observed in wheat and other crops,no significant differences in selection pressure were detected between the subgenomes in E.oryzicola and E.crus-galli.In addition,distinctive differences in subgenome transcriptome dynamics during hexaploidization were observed between E.crus-galli and bread wheat.Collectively,our study documents genomic mechanisms underlying the adaptation of a major agricultural weed during polyploidization.The genomic and transcriptomic resources of three Echinochloa species and new insights into the polyploidization-driven adaptive evolution would be useful for future breeding cereal crops.

How does contemporary climate versus climate change velocity affect endemic plant species richness in China?

Climate change is considered a top threat to biodiversity, but the relative roles of contemporary climate versus the rate of climate change in determining spatial patterns of biodiversity are far from clear. China has a very diverse flora and harbors a high percentage of endemic species, but the mechanisms underlying spatial patterns of plant endemism are poorly understood. This study explores the geographical patterns of a representative sample of 555 endemic seed plant species at the scale of 0.5° latitude 9 0.5° longitude. Ordinary least squares and spatial autoregressive models were compared to assess the relationship between richness of endemics and the rate of climate change in the past century, as well as a group of contemporary climate variables. In China, a high level of endemism was associated with high elevation and low rate of climate change. However, contemporary climate had a stronger impact than climate change velocity in the past century on endemic species richness patterns. Specifically,mean annual precipitation and annual range of temperature were important contemporary climatic factors. The rate of change of annual mean temperature, but not that of annual precipitation, also significantly contributed to the spatial pattern of plant endemic species richness. We found no significant relationship between topographic variation and endemic species richness, while temperature variability at multiple time scales was strongly correlated with the species richness pattern. Future work should consider the direction of climate change and incorporate higher-resolution data.

Altitudinal patterns of maximum plant height on the Tibetan Plateau

Aims Several studies have shown that plant height changes along environmen-tal gradients.However,altitudinal patterns of plant height across species are still unclear,especially in regions sensitive to climate change.As canopy height decreases dramatically near the tree line in alpine areas,we hypothesize that plant height across all species also decreases with increasing altitude,and distinct thresholds exist along this gradient.Methods Using a large dataset of maximum plant height and elevation range(400 to 6000 m a.s.l.)of 4295 angiosperms from the regional flora of the Tibetan Plateau,we regressed plant height for every 100 m belt against elevation to explore the relationships.To identify the approximate boundaries where dramatic changes in plant height occurs for herbaceous plants,shrubs,trees,woody plants and all angiosperms,we used piecewise linear regression.Phylogenetically independent contrast was used to test the potential evolutionary influences on altitudinal patterns at the family level.Important Findings Results showed that for herbaceous plants,shrubs,trees,woody plants and all angiosperms,plant height decreases significantly as altitude increases.In addition,we found that altitude,a proxy for many environmental factors,had obvious thresholds(breakpoints)dictating patterns of plant height.The results of phylogenetically independent contrast also emphasized the importance of evolution-ary history in determining the altitudinal patterns of plant height for some growth forms.Our results highlight the relative intense filter-ing effect of environmental factors in shaping patterns of functional traits and how this could vary for different ranges of environmental variables.

PlantcircBase： A Database for Plant Circular RNAs

Dear Editor Circular RNAs （circRNAs） are a kind of non-coding RNAs; they were first found over 35 years ago but have only become a research hotspot in recent years. CircRNAs are covalently closed loops derived from precursor mRNAs by non-sequential back-splicing. Based on their genomic location, circRNAs can be classified into exonic, intronic, intergenic, and exon-intronic circRNAs （Chen, 2016）. By taking advantages of recent advances in bioinformatics algorithms, a large number of circRNAs have been detected among diverse organisms,

Environmental landscape determinants of maximum forest canopy height of boreal forests

Aims Canopy height is a key driver of forest biodiversity and carbon cycling.Accurate estimates of canopy height are needed for assess-ing mechanisms relating to ecological patterns and processes of tree height limitations.At global scales forest canopy height patterns are largely controlled by climate,while local variation at fine scales is due to differences in disturbance history and local patterns in envir-onmental conditions.The relative effect of local environmental driv-ers on canopy height is poorly understood partly due to gaps in data on canopy height and methods for examining limiting factors.Here,we used airborne laser scanning(ALS)data on vegetation structure of boreal forests to examine the effects of environmental factors on potential maximum forest canopy height.Methods Relationships between maximum canopy height from ALS meas-ures and environmental variables were examined to assess factors limiting tree height.Specifically,we used quantile regression at the 0.90 quantile to relate maximum canopy height with environmental characteristics of climate(i.e.mean annual temperature[MAT]and mean annual precipitation),terrain(i.e.slope)and depth-to-water(DTW)across a 33000 km2 multiple use boreal forest landscape in northeast Alberta,Canada.Important Findings Maximum canopy height was positively associated with MAT,ter-rain slope and terrain-derived DTW,collectively explaining 33.2%of the variation in heights.The strongest explanatory variable was DTW explaining 26%of canopy height variation with peatland forests having naturally shorter maximum canopy heights,but also more sites currently at their maximum potential height.In con-trast,the most productive forests(i.e.mesic to xeric upland forests)had the fewest sites at their potential maximum height,illustrating the effects of long-term forest management,wildfires and general anthropogenic footprints on reducing the extent and abundance of older,taller forest habitat in Alberta’s boreal forest.

Doped microspheres for whispering gallery mode microlasing

Whispering gallery mode(WGM)optical microcavities,which are capable of light field confinement and manipulation in a relatively small volume,have gained considerable attention from fundamentals in enhanced light-matter interactions to laser applications[1].Undergoing decades of development,the improvement of lasing performance is always a significant issue,including low threshold and high quality(Q)factor[2].Increasing optical gain and reducing the losses are the key aspects towards the realization of a high-quality WGM laser.A perfect cavity structure and a smooth surface are the most crucial determinants to reduce optical losses and enhance light field confined abilities.