基于FP-growth算法的交通事故数据关联规则挖掘研究

为了探寻多种事故影响因素共同作用下诱发交通事故的某种规律以及各因素间的关系,本文采用FP-growth算法对收集到的交通事故数据进行分析研究,挖掘其中的潜在价值信息,找出事故发生的原因,根据分析结果给相关部门提出建议,帮助城市交通管理者制定更有效的管理措施,以达到降低交通事故发生频率的目的。

Serial Multiple Mediation of the Relationshipbetween Positive Coping Style and PostTraumatic Growth among Chinese CollegeStudents in the Aftermath of COVID-19

Given the ongoing character of COVID-19, higher-education students encountered multifaceted pressures brought about by thepandemic and had to overcome many difficulties during this period. Accordingly, it is imperative to identify the factors that mayhave protective effects on the social functioning and mental status of college students in the aftermath of COVID-19. This crosssectional study sought to ascertain the internal mechanism of positive coping (PC) styles affecting post-traumatic growth (PTG)and considered the mediating roles of cognitive reappraisal (CR), psychological resilience (PR), and deliberate rumination (DR),which are essential for understanding how and to what extent these factors shaped PTG in the context of the present pandemic. 463Chinese college students recruited via a convenience sampling method completed a set of online self-report measures of PC, PTG,CR, PR and DR. The findings revealed that the abovementioned five variables were positively correlated with each other, and theindependent variable directly predicted the dependent variable. More importantly, two out of three mediators in parallel mediatedthe relationship between PC and PTG, illustrating that more PC adoption was associated with increased PTG through high levels ofPR and DR, respectively. The two significant serial mediating effects also indicated that PC could contribute to CR, which furtherfacilitates either PR or DR and subsequently promotes the development of PTG. Colleges should adopt routine protectivebehaviors in accordance with such evidence to strengthen students’ mental health education and establish scientific methods toboost their psychological well-being. Overall, our results may shed new light on the process of positive adaption and providetheoretical support for targeted crisis intervention during the late phase of the pandemic.

Comparison of posttraumatic growth and posttraumatic stress of nurses with physicians and medical students after caring of COVID‑19 patients

Objectives:The present study compared the prevalence and psychosocial factors affecting posttraumatic growth(PTG),posttraumatic stress disorder(PTSD),and psychological distress in nurses,physicians,and medical students.Materials and Methods:In a cross‑sectional study,three groups of medical staff including nurses(n=57),physicians(n=40),and medical students(n=34)who were responsible for the care/treatment of COVID‑19 patients admitted to a general hospital for 4 months responded to Posttraumatic Growth Inventory,Brief Symptom Inventory‑18,Resilience Questionnaire,PTSD Screen,and Social Capital‑Integrated Questionnaire.Results:After the exposure of medical staff to at least 4 months of treatment/care of COVID‑19 patients,PTG prevalence was higher than PTSD(38.2%vs.14.6%),but they experienced some degrees of psychological distress(65.5%).The nurses had 8.33(confidence interval[CI]:2.5–26.7)times higher PTG rate than medical students(P<0.001).Physicists also experienced 5.00(CI:1.4–26.7)times higher PTG than medical students(P<0.001).PTG was aided by age,married status,strong resilience,and high social capital,but gender had no influence.Resilience played an important protective role to prevent the incidence of psychological distress in nurses,medical students,and physicians.Conclusion:Despite the fact that the PTSD and psychological distress were same in the three groups of medical staff,the nurses had a greater rate of PTG than physicians and medical students.

基于FP-growth的老年行人交通事故损伤致因研究

为研究老年行人交通事故相关因素及其对损伤程度的影响,以中国交通事故深度调查数据库中2013—2023年710起机动车-老年行人事故为分析对象,利用FP-growth算法挖掘出4类影响因素28个类型变量共5594项关联规则。研究结果表明:行人年龄、碰撞速度、事故时间段及事故地点是影响老年行人事故死亡率的显著因素。特别是,行人年龄和碰撞速度对死亡率有显著影响,随着碰撞速度的增加,死亡率显著上升;60岁及以上老年行人年龄每增加1岁,其死亡率提升0.037倍。此外,事故发生在夜间、郊区或村庄的死亡率更高。研究结果可为提高老年行人交通安全,制定相关安全措施提供一定参考。

Effects of thinning on the understory light environment of different stands and the photosynthetic performance and growth of the reforestation species Phoebe bournei

Light levels determine regeneration in stands and a key concern is how to regulate the light environment of different stand types to the requirements of the understory.In this study,we selected three stands typical in south China(a Cryptomeria japonica plantation,a Quercus acutissima plantation,and a mixed stand of both)and three thinning intensities to determine the best understory light environ-ment for 3-year-old Phoebe bournei seedlings.The canopy structure,understory light environment,and photosynthe-sis and growth indicators were assessed following thin-ning.Thinning improved canopy structure and understory light availability of each stand;species composition was the reason for differences in the understory light environ-ment.Under the same thinning intensity,the mixed stand had the greatest light radiation and most balanced spectral composition.P.bournei photosynthesis and growth were closely related to the light environment;all three stands required heavy thinning to create an effective and sustained understory light environment.In a suitable understory light environment,the efficiency of light interception,absorption,and use by seedlings was enhanced,resulting in a higher carbon assimilation the main limiting factor was stomatal conductance.As a shade-avoidance signal,red/far-red radia-tion is a critical factor driving changes in photosynthesis and growth of P.bournei seedlings,and a reduction increased light absorption and use capacity and height:diameter ratios.The growth advantage transformed from diameter to height,enabling seedlings to access more light.Our findings suggest that the regeneration of shade-tolerant species such as P.bournei could be enhanced if a targeted approach to thinning based on stand type was adopted.

GbLMI1 over-expression improves cotton aboveground vegetative growth

Leaves are the main organ for photosynthesis and organic synthesis in cotton.Leaf shape has important effects on photosynthetic efficiency and canopy formation,thereby affecting cotton yield.Previous studies have shown that LMI1(LATE MERISTEM IDENTITY1)is the main gene regulating leaf shape.In this study,the LMI1 gene was inserted into the 35S promoter expression vector,and cotton plants overexpressing LMI1(OE)were obtained through genetic transformation.Statistical analysis of the biological traits of the T_(1) and T_(2) populations showed that compared to the wild type(WT),OE plants had significantly larger leaves,thicker stems and significantly greater dry weight.Furthermore,plant sections of the main vein and petiole showed that the numbers of cells in those tissues of OE plants were significantly greater.In addition,RNA-seq analysis revealed the differential expression of genes related to gibberellin synthesis and NAC gene family(genes containing the NAC domain)between the OE and WT plants,suggesting that LMI1 is involved in secondary wall formation and cell proliferation,which promotes stem thickening.Moreover,Gene Ontology(GO)analysis revealed enrichment in the terms of calcium ion binding,and Kyoto Encyclopedia of Genes and Genomes(KEGG)analysis showed enrichment in the terms of fatty acid degradation,phosphatidylinositol signal transduction system,and c AMP(cyclic adenosine monophosphate)signal pathway.These results suggested that LMI1 OE plants are responsive to gibberellin hormone signals,and have altered messenger signals(c AMP,Ca^(2+))which amplify this function,to promote stronger aboveground vegetative growth.This study found the LMI1 greatly increased the vegetative growth in cotton,which is the basic requirement for higher yield.

Dynamic changes of rumen microbiota and serum metabolome revealed increases in meat quality and growth performances of sheep fed bio‑fermented rice straw

Background Providing high-quality roughage is crucial for improvement of ruminant production because it is an essential component of their feed.Our previous study showed that feeding bio-fermented rice straw(BF)improved the feed intake and weight gain of sheep.However,it remains unclear why feeding BF to sheep increased their feed intake and weight gain.Therefore,the purposes of this research were to investigate how the rumen micro-biota and serum metabolome are dynamically changing after feeding BF,as well as how their changes influence the feed intake,digestibility,nutrient transport,meat quality and growth performances of sheep.Twelve growing Hu sheep were allocated into 3 groups:alfalfa hay fed group(AH:positive control),rice straw fed group(RS:negative control)and BF fed group(BF:treatment).Samples of rumen content,blood,rumen epithelium,muscle,feed offered and refusals were collected for the subsequent analysis.Results Feeding BF changed the microbial community and rumen fermentation,particularly increasing(P<0.05)relative abundance of Prevotella and propionate production,and decreasing(P<0.05)enteric methane yield.The histomorphology(height,width,area and thickness)of rumen papillae and gene expression for carbohydrate trans-port(MCT1),tight junction(claudin-1,claudin-4),and cell proliferation(CDK4,Cyclin A2,Cyclin E1)were improved(P<0.05)in sheep fed BF.Additionally,serum metabolome was also dynamically changed,which led to up-regulating(P<0.05)the primary bile acid biosynthesis and biosynthesis of unsaturated fatty acid in sheep fed BF.As a result,the higher(P<0.05)feed intake,digestibility,growth rate,feed efficiency,meat quality and mono-unsaturated fatty acid concentration in muscle,and the lower(P<0.05)feed cost per kg of live weight were achieved by feeding BF.Conclusions Feeding BF improved the growth performances and meat quality of sheep and reduced their feed cost.Therefore,bio-fermentation of rice straw could be an innovative way for improving ruminant production with mini-mizing production costs.

Role of transforming growth factor-βin peripheral nerve regeneration

Injuries caused by trauma and neurodegenerative diseases can damage the peripheral nervous system and cause functional deficits.Unlike in the central nervous system,damaged axons in peripheral nerves can be induced to regenerate in response to intrinsic cues after reprogramming or in a growth-promoting microenvironment created by Schwann cells.However,axon regeneration and repair do not automatically result in the restoration of function,which is the ultimate therapeutic goal but also a major clinical challenge.Transforming growth factor(TGF)is a multifunctional cytokine that regulates various biological processes including tissue repair,embryo development,and cell growth and differentiation.There is accumulating evidence that TGF-βfamily proteins participate in peripheral nerve repair through various factors and signaling pathways by regulating the growth and transformation of Schwann cells;recruiting specific immune cells;controlling the permeability of the blood-nerve barrier,thereby stimulating axon growth;and inhibiting remyelination of regenerated axons.TGF-βhas been applied to the treatment of peripheral nerve injury in animal models.In this context,we review the functions of TGF-βin peripheral nerve regeneration and potential clinical applications.

Activation of endogenous neurogenesis and angiogenesis by basic fibroblast growth factor-chitosan gel in an adult rat model of ischemic stroke

Attempts have been made to use cell transplantation and biomaterials to promote cell proliferation,differentiation,migration,and survival,as well as angiogenesis,in the context of brain injury.However,whether bioactive materials can repair the damage caused by ischemic stroke by activating endogenous neurogenesis and angiogenesis is still unknown.In this study,we applied chitosan gel loaded with basic fibroblast growth factor to the stroke cavity 7 days after ischemic stroke in rats.The gel slowly released basic fibroblast growth factor,which improved the local microenvironment,activated endogenous neural stem/progenitor cells,and recruited these cells to migrate toward the penumbra and stroke cavity and subsequently differentiate into neurons,while enhancing angiogenesis in the penumbra and stroke cavity and ultimately leading to partial functional recovery.This study revealed the mechanism by which bioactive materials repair ischemic strokes,thus providing a new strategy for the clinical application of bioactive materials in the treatment of ischemic stroke.

Delineation of urban growth boundary based on FLUS model under the perspective of land use evaluation in hilly mountainous areas

With rapid economic development,the size of urban land in China is expanding dramatically.The Urban Growth Boundary(UGB)is an expandable spatial boundary for urban construction in a certain period in order to control the urban sprawl.Reasonable delineation of UGB can inhibit the disorderly spread of urban space and guide the normal development of the city.It is of practical significance for the construction of green urban space.The study utilizes GIS technology to establish a land construction suitability evaluation system for Nankang city,which is experiencing rapid urban expansion,and outlines the preliminary UGB under the future land use simulation(FLUS)model.At the same time,considering the coupled coordination of"Production-Living-Ecological Space",and based on the suitability evaluation,we revised the preliminary UGB by combining the advantages of the patch-generating land use simulation(PLUS)model and the convex hull model to delineate the final UGB.The results show that:1)the comprehensive score of the evaluation of the suitability of the construction of land from high to low shows the distribution of the center of the city to the surrounding circle type spread,the center of the city has the highest suitability score.The results of convex hull model show that the urban expansion type of Nankang is epitaxial.In the future,the urban expansion will mainly occur in the northern part of the city.The PLUS model predicts an increase of 3359.97 hm^(2)of construction land in Nankang by 2035,of which 2022.97 hm^(2)is urban construction land.2)The FLUS model has a prediction accuracy of 86.3%and delineates a preliminary UGB area of 9215.07 hm^(2).3)We used the results of the construction suitability evaluation,PLUS model simulation results,and convex hull model predictions to revise the originally delineated UGB.The final delineated UGB area is 8895.67 hm^(2)and it is capable of meeting the future development of the study area.The results of the delineation can promote sustainable urban development,and the delineation methodology can provide a reference basis for the preparation of territorial spatial planning.

PRaG 3.0 therapy for human epidermal growth factor receptor 2-positive metastatic pancreatic ductal adenocarcinoma:A case report

BACKGROUND Pancreatic ductal adenocarcinoma(PDAC)is a highly fatal disease with limited effective treatment especially after first-line chemotherapy.The human epidermal growth factor receptor 2(HER-2)immunohistochemistry(IHC)positive is associated with more aggressive clinical behavior and shorter overall survival in PDAC.CASE SUMMARY We present a case of multiple metastatic PDAC with IHC mismatch repair proficient but HER-2 IHC weakly positive at diagnosis that didn’t have tumor regression after first-line nab-paclitaxel plus gemcitabine and PD-1 inhibitor treatment.A novel combination therapy PRaG 3.0 of RC48(HER2-antibody-drug conjugate),radio-therapy,PD-1 inhibitor,granulocyte-macrophage colony-stimulating factor and interleukin-2 was then applied as second-line therapy and the patient had confirmed good partial response with progress-free-survival of 6.5 months and overall survival of 14.2 month.She had not developed any grade 2 or above treatment-related adverse events at any point.Percentage of peripheral CD8^(+) Temra and CD4^(+) Temra were increased during first two activation cycles of PRaG 3.0 treatment containing radiotherapy but deceased to the baseline during the maintenance cycles containing no radiotherapy.CONCLUSION PRaG 3.0 might be a novel strategy for HER2-positive metastatic PDAC patients who failed from previous first-line approach and even PD-1 immunotherapy but needs more data in prospective trials.

Effects of drip and flood irrigation on carbon dioxide exchange and crop growth in the maize ecosystem in the Hetao Irrigation District,China

Drip irrigation and flood irrigation are major irrigation methods for maize crops in the Hetao Irrigation District,Inner Mongolia Autonomous Region,China.This research delves into the effects of these irrigation methods on carbon dioxide(CO_(2))exchange and crop growth in this region.The experimental site was divided into drip and flood irrigation zones.The irrigation schedules of this study aligned with the local commonly used irrigation schedule.We employed a developed chamber system to measure the diurnal CO_(2)exchange of maize plants during various growth stages under both drip and flood irrigation methods.From May to September in 2020 and 2021,two sets of repeated experiments were conducted.In each experiment,a total of nine measurements of CO_(2)exchange were performed to obtain carbon exchange data at different growth stages of maize crop.During each CO_(2)exchange measurement event,CO_(2)flux data were collected every two hours over a day-long period to capture the diurnal variations in CO_(2)exchange.During each CO_(2)exchange measurement event,the biological parameters(aboveground biomass and crop growth rate)of maize and environmental parameters(including air humidity,air temperature,precipitation,soil water content,and photosynthetically active radiation)were measured.The results indicated a V-shaped trend in net ecosystem CO_(2)exchange in daytime,reducing slowly at night,while the net assimilation rate(net primary productivity)exhibited a contrasting trend.Notably,compared with flood irrigation,drip irrigation demonstrated significantly higher average daily soil CO_(2)emission and greater average daily CO_(2)absorption by maize plants.Consequently,within the maize ecosystem,drip irrigation appeared more conducive to absorbing atmospheric CO_(2).Furthermore,drip irrigation demonstrated a faster crop growth rate and increased aboveground biomass compared with flood irrigation.A strong linear relationship existed between leaf area index and light utilization efficiency,irrespective of the irrigation method.Notably,drip irrigation displayed superior light use efficiency compared with flood irrigation.The final yield results corroborated these findings,indicating that drip irrigation yielded higher harvest index and overall yield than flood irrigation.The results of this study provide a basis for the selection of optimal irrigation methods commonly used in the Hetao Irrigation District.This research also serves as a reference for future irrigation studies that consider measurements of both carbon emissions and yield simultaneously.

Spectral purification improves monitoring accuracy of the comprehensive growth evaluation index for film-mulched winter wheat

In order to further improve the utility of unmanned aerial vehicle(UAV)remote-sensing for quickly and accurately monitoring the growth of winter wheat under film mulching, this study examined the treatments of ridge mulching,ridge–furrow full mulching, and flat cropping full mulching in winter wheat.Based on the fuzzy comprehensive evaluation (FCE) method, four agronomic parameters (leaf area index, above-ground biomass, plant height, and leaf chlorophyll content) were used to calculate the comprehensive growth evaluation index (CGEI) of the winter wheat, and 14 visible and near-infrared spectral indices were calculated using spectral purification technology to process the remote-sensing image data of winter wheat obtained by multispectral UAV.Four machine learning algorithms, partial least squares, support vector machines, random forests, and artificial neural network networks(ANN), were used to build the winter wheat growth monitoring model under film mulching, and accuracy evaluation and mapping of the spatial and temporal distribution of winter wheat growth status were carried out.The results showed that the CGEI of winter wheat under film mulching constructed using the FCE method could objectively and comprehensively evaluate the crop growth status.The accuracy of remote-sensing inversion of the CGEI based on the ANN model was higher than for the individual agronomic parameters, with a coefficient of determination of 0.75,a root mean square error of 8.40, and a mean absolute value error of 6.53.Spectral purification could eliminate the interference of background effects caused by mulching and soil, effectively improving the accuracy of the remotesensing inversion of winter wheat under film mulching, with the best inversion effect achieved on the ridge–furrow full mulching area after spectral purification.The results of this study provide a theoretical reference for the use of UAV remote-sensing to monitor the growth status of winter wheat with film mulching.

Role of bisphosphonates in osteoporosis caused by adult growth hormone deficiency

In recent years,growth hormone and insulin-like growth factors have become key regulators of bone metabolism and remodeling,crucial for maintaining healthy bone mass throughout life.Studies have shown that adult growth hormone deficiency leads to alterations in bone remodeling,significantly affecting bone microarchitecture and increasing fracture risk.Although recombinant human growth hormone replacement therapy can mitigate these adverse effects,improving bone density,and reduce fracture risk,its effectiveness in treating osteoporosis,especially in adults with established growth hormone deficiency,seems limited.Bisphosphonates inhibit bone resorption by targeting farnesyl pyrophosphate synthase in osteoclasts,and clinical trials have confirmed their efficacy in improving osteoporosis.Therefore,for adult growth hormone deficiency patients with osteoporosis,the use of bisphosphonates alongside growth hormone replacement therapy is recommended.

Effect of Titanium Dioxide Nanoparticles on Growth and Biomass Accumulation in Lettuce (Lactuca sativa)

The use of titanium dioxide nanoparticles (nTiO2) is gaining interest in agriculture because of their impact on many aspects of plant growth. The present study examines the effects of nTiO2 (5 nm and 10 nm) applied to seeds and the seedlings as a foliar application on various aspects of growth characteristics and biomass accumulation in lettuce (Lactuca sativa, cv. Grand Rapids). Application of 10 nm nTiO2 to seeds through imbibition resulted in a significant reduction in shoot biomass accumulation while 5 nm nTiO2 did not affect the biomass accumulation in lettuce. The application of 10 nm nTiO2 reduced the fresh shoot biomass accumulation by about 18% compared to the control plants. Other growth characteristics such as shoot dry biomass, root fresh and dry biomass, plant height, and leaf area were not affected by the application of both 5 nm and 10 nm nTiO2. In addition, foliar application of these nanoparticles to the lettuce seedlings did not have a significant effect on most of the growth parameters examined, and the increasing concentration ranging from 5 nm/L to 400 mg/L did not produce a consistent response in lettuce. Thus, nTiO2 application to lettuce seeds had a notable negative impact on shoot growth while foliar application did not have a significant effect on many plant growth characteristics. However, foliar applications produced some symptoms of toxicity to the foliage in the form of necrotic or chlorotic patches on the leaves, which were more pronounced with increasing concentrations of both 5 nm and 10 nm nTiO2. However, these symptoms were apparent at a concentration as low as 50 mg/L of nTiO2. Thus, foliar application of nTiO2 may not have a significant impact on many of the growth characteristics in lettuce, but it can result in foliar toxicity.

Bio-Fertilizer Improved Oil Palm Seedling Growth

In most farming systems newly introduced commercial fertilizers to be accepted, adopted and used by farmers, their effectiveness and appropriate application rates must be exhibited. This study was conducted to validate the effect and rates of a bio-fertilizer (super agric) on oil palm seedling growth. The trial was laid out in a randomized complete block design (RCBD) with three application rates of 0, 4 and 8 ml/L of water (treatments) replicated thrice. Following the application of super agric to oil palm seedlings for a period of six months, observations drawn from the analysis of growth data were as follows: Three months after treatment, super agric significantly (P < 0.05) increased the height and breadth of oil palm seedling compared to those which were not applied with super agric. The results also showed that when super agric was applied at a rate of 4 ml/L, the leaf length and breadth were higher compared to the control were super agric was not used. Furthermore, applications of super agric improved oil palm seedling nitrogen uptake by 31% in treatment groups as compared to the control which explained the height and breadth increase in the oil palm seedlings that were applied with super agric. On the other hand, the effect of super agric application on phosphorus uptake by seedlings was not significant. Although the height, breadth, leaf width and length were all significantly affected by super agric application, the number of oil palm leaves and spears were not affected for the period the experiment was conducted. Six months after application of super agric the growth of oil palm seedlings was favorably impacted, hence we recommend super agric to be promoted among oil palm seedling growers.

Genome-Wide Association Study and Genomic Selection for Plant Growth Habit in Peanuts Using the USDA Public Data

Peanut (Arachis hypogaea L.) production is valued at $1.28 billion annually in the USA. Plant growth habit can be used to determine plant population density and cultivation practices a given farmer uses. Erect plants are generally more compact and can be more densely planted unlike plants with more prostrate growth. The objectives of this study were to analyze publicly available datasets to identify single-nucleotide polymorphism (SNP) markers associated with plant growth habit in peanuts and to conduct genomic selection. A genome-wide association study (GWAS) was used to identify SNPs for growth habit type among 775 USDA peanut accessions. A total of 13,306 SNPs were used to conduct GWAS using five statistical models. The models used were single-marker regression, generalized linear model (PCA), generalized linear model (Q), mixed linear model (PCA), and mixed linear model (Q) and a total of 181, 1, 108, 1, and 10 SNPs were found associated with growth habit respectively. Based on this dataset, results showed that genomic selection can achieve up to 61% accuracy, depending on the training population size being used for the prediction. SNP AX-176821681 was found in all models. Gene ontology for this location shows an annotated gene, Araip.0F3YM, found 2485 bp upstream of this SNP and encodes for a peptidyl-prolyl cis-trans isomerase. To the best of our knowledge, this is the first report identifying molecular markers linked to plant growth habit type in peanuts. This finding suggests that a molecular marker can be developed to identify specific plant growth habits in peanuts, enabling early generation selection by peanut breeders.

Growth hormone promotes the reconstruction of injured axons in the hypothalamo-neurohypophyseal system

Previous studies have shown that growth hormone can regulate hypothalamic energy metabolism, stress, and hormone release. Therefore, growth hormone has great potential for treating hypothalamic injury. In this study, we established a specific hypothalamic axon injury model by inducing hypothalamic pituitary stalk electric lesions in male mice. We then treated mice by intraperitoneal administration of growth hormone. Our results showed that growth hormone increased the expression of insulin-like growth factor 1 and its receptors, and promoted the survival of hypothalamic neurons, axonal regeneration, and vascular reconstruction from the median eminence through the posterior pituitary. Altogether, this alleviated hypothalamic injury-caused central diabetes insipidus and anxiety. These results suggest that growth hormone can promote axonal reconstruction after hypothalamic injury by regulating the growth hormone-insulin-like growth factor 1 axis.

Root overlap and allocation of above- and belowground growth of European beech in pure and mixed stands of Douglas fir and Norway spruce

Site conditions and species identity have a combined effect on fine root growth of trees in pure and mixed stands.However,mechanisms that may contribute to this effect are rarely studied,even though they are essential to assess the potential of species to cope with climate change.This study examined fine root overlap and the linkage between fine root and stem growth of European beech(Fagus sylvatica)growing in pure and mixed stands with Douglas fir(Pseudotsuga menziesii)or Norway spruce(Picea abies)at two different study sites in northwestern Germany.The study sites represented substantially different soil and climate conditions.At each site,three stands,and at each stand,three pairs of trees were studied.In the pure beech stand,the pairs consisted of two beech trees,while in the mixed stands each pair was composed of a beech tree and a conifer.Between each pair,three evenly spaced soil cores were taken monthly throughout the growing season.In the pure beech stands,microsatellite markers were used to assign the fine roots to individual trees.Changes in stem diameter of beech were quantified and then upscaled to aboveground wood productivity with automatic high-resolution circumference dendrometers.We found that fine root overlap between neighboring trees varied independently of the distance between the paired trees or the stand types(pure versus mixed stands),indicating that there was no territorial competition.Aboveground wood productivity(wood NPP)and fine root productivity(root NPP)showed similar unimodal seasonal patterns,peaking in June.However,this pattern was more distinct for root NPP,and root NPP started earlier and lasted longer than wood NPP.The influence of site conditions on the variation in wood and root NPP of beech was stronger than that of stand type.Wood NPP was,as expected,higher at the richer site than at the poorer site.In contrast,root NPP was higher at the poorer than at the richer site.We concluded that beech can respond to limited resources not only above-but also belowground and that the negative relationship between above-and belowground growth across the study sites suggests an‘optimal partitioning’of growth under stress.

Growth and inhibition of zinc anode dendrites in Zn-air batteries:Model and experiment

Zinc(Zn)-air batteries are widely used in secondary battery research owing to their high theoretical energy density,good electrochemical reversibility,stable discharge performance,and low cost of the anode active material Zn.However,the Zn anode also leads to many challenges,including dendrite growth,deformation,and hydrogen precipitation self-corrosion.In this context,Zn dendrite growth has a greater impact on the cycle lives.In this dissertation,a dendrite growth model for a Zn-air battery was established based on electrochemical phase field theory,and the effects of the charging time,anisotropy strength,and electrolyte temperature on the morphology and growth height of Zn dendrites were studied.A series of experiments was designed with different gradient influencing factors in subsequent experiments to verify the theoretical simulations,including elevated electrolyte temperatures,flowing electrolytes,and pulsed charging.The simulation results show that the growth of Zn dendrites is controlled mainly by diffusion and mass transfer processes,whereas the electrolyte temperature,flow rate,and interfacial energy anisotropy intensity are the main factors.The experimental results show that an optimal electrolyte temperature of 343.15 K,an optimal electrolyte flow rate of 40 ml·min^(-1),and an effective pulse charging mode.