Tree failure modes influenced by the characteristics of tree and its root distribution caused by debris flows

Forests play an important role in controlling the formation and movement processes of debris flows.They contribute to soil stabilization,regulation of soil water content,and act as robust structures impeding the downstream progression of debris flows.On the positive side,trees,to some extent,can intercept debris flows and effectively mitigate their velocity by increasing flow resistance.On the negative side,trees may suffer damage from debris-flow hazards,characterized by the generation of substantial quantities of wood fragments and consequential ramifications such as river channel blockage,resulting in backwater rise.In extreme cases,this blockage collapse can lead to instantaneous discharge amplification,thereby adversely impacting urban safety and impeding sustainable development.Therefore,in order to grasp the effects of tree characteristics on tree failure modes,the tree failure modes and corresponding parameters,diameters at breast height(DBH)and root-soil plate size,were identified and recorded through the post-event field investigation in Keze Gully,a region prone to debrisflow events in Sichuan,China,respectively.To investigate the impact of spatial variability in tree root distribution on tree failure modes,the root crosssectional area ratio(RAR),root density(RD),root length density(RLD)and soil detachment rate(SDR)were obtained.The findings indicated that:(1)Tree characteristics reflect the interactions of debris flows and trees,and influence the tree failure modes ultimately.The root distribution characteristics influence the size and shape of the root-soil plate to affect the resistance of trees.(2)Compared to burial and abrasion,stem breakage and overturning are the predominant modes of tree failure in debris-flow hazards.Trees with a smaller DBH primarily experience stem breakage and bending,and trees with a larger DBH mostly experience overturning.(3)The root-soil plate shapes of overturned trees,affected by the root architecture and root growth range,are generally semielliptical or semicircular,and the horizontal and vertical radii increase with DBH,but the correlation between the root-soil plate’s breadth-depth ratio and DBH is low.(4)The biomass and RAR decrease with distance.The RAR distribution exhibit the order of upslope direction>downslope direction>lateral direction.The coarse root biomass significantly increases with DBH,but no clear trend in fine root biomass.(5)The roots can significantly enhance the soil erosion resistance,but the erosion resistance of coarse roots is not as significant as that of fine roots.The erosion resistance increases with DBH,and follows the order of upslope direction>downslope direction>lateral direction.The results could provide new insights into the influences of tree and root distribution characteristics on tree failure modes during debris flows.

Studies on the Root Characteristics of Maize Varieties of Different Eras

Experiment was conducted at the Gongzhuling Experimental Station of Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, Jilin Province, China, during 2009-2010. Six representative varieties of maize （Baihe in the 1950s, Jidan 101 in the 1960s, Zhongdan 2 in the 1970s, Yedan 13 in the 1980s, Zhengdan 958 in the 1990s, and Xianyu 335 in the 2000s） were each planted under two different densities （52 500 and 82 500 plants ha-~） and two different nitrogen application levels （150 and 300 kg ha-l）. Root characteristics and distribution among soil layers were studied by the field root digging method. The results showed that root mass increased with the process of the growth and development of the plant, and it peaked at kernel filling stage, and decreased at maturity due to the root senesces. Root mass of different maize varieties from the 1950s to 1980s had a trend of increase, while it decreased for the modern varieties. Root length and root surface areas had the similar changing trend. The study suggested that early maize varieties may have root redundancy, and reducing root redundancy may be a direction for variety improvement for high yield. Root characteristics were affected by nitrogen application level and density; modern varieties were more suitable for higher fertilizer application level and density conditions. Root characteristics distribution among soil layers decreased by an exponent equation, but the regression coefficients of different varieties were different. Though the root length density （RLD） of every soil layer of different varieties also decreased by an exponent equation, there were large variations of RLD in every part of a layer.

Feasibility of Transferring Drinking Water from the Senegal River in the East (Backel) to the West Center (Fatick) in Senegal

Every year, 24 billion m3 of fresh water are thrown into the sea by the Senegal River, while most of the country’s populations do not have permanent access to drinking water. Also, agricultural land, which extends as far as the eye can see, is only used during winter periods, thus slowing down the development of agriculture. It is in this context that this article studies the feasibility of transferring drinking water from the Senegal River in the east of the country to the center-west through a transfer canal to meet the drinking water needs of the populations. In addition, we intend to flood the fossil valleys from this canal and recharge the aquifers. The watershed resulting from the juxtaposition of the two watersheds which dominate central Senegal has a slightly descending profile from Bakel to Fatick. This promotes gravity flow of water over 542 km. This analysis is carried out by the Glabal Mapper software and SRTM1 images. We report that all water needs have been estimated at approximately 70 m3/s based on the ANDS census in 2023, the distribution of arable land and groundwater recharge areas in the country. The waters flowing in the canal have depths (draft) not reaching 4.6 m. These results are obtained by applying the Manning Strickler equation, on a channel with a straight cross-section in the shape of a trapezoid and lined with sand concrete. The canal thus designed will bring water to populations and arid zones in the central and central-western regions of the country where problems persist. However, it will be necessary to overcome a difference in altitude of 96 m over 30 km to raise the water from the river to the threshold of the canal in order to ensure the flow in the latter. We have retained two calculation variants (Canal + Pumping or Single Pumping) whose pumping stations will be powered by solar fields. Due to the heavy investments, the installations upstream of the canal will be modular over time. Consequently, the central canal project will be constructed in six (6) phases of ten (10) years.

Comparison Experiment of Root Cutting to Castanopsis tibetana Hance between Different Provenances at Seedling Stage

Castanopsis tibetana of five different provenances （Jinxiu, Longsheng, Ziyuan, Hezhou and Leye） were selected as experimental materials to investigate the effects of treatments combining different root lengths and contents of rooting agent on the growth of C. tibetana after transplanting of seedlings. The results showed that, there were significant differences in the preserving rate of C. tibetana seedlings between different provenances and different treatments. Among the 5 treatments, the seedlings of Hezhou provenance showed the maximum annual increment of ground diameter, and the seedlings of Ziyuan provenance exhibited the maximum annual increment of seedling height. Therefore, the germplasm from Hezhou provenance might be better than those from other provenances.

Differential response of root morphology to potassium deficient stress among rice genotypes varying in potassium efficiency

Disparity in the root morphology of six rice(Oryza sativa L.) genotypes varying in potassium(K) efficiency was studied with three K levels:5 mg/L(low),10 mg/L(moderate) and 40 mg/L(adequate) in hydroponic culture. Morphological parameters included root length,surface area,volume and count of lateral roots,as well as fine(diameter<0.2 mm) and thick(diameter>0.2 mm) roots. The results indicate that the root growth of all genotypes was reduced under low K,but moderate K deficiency increased the root length of the efficient genotypes. At deficient and moderate K levels,all the efficient rice genotypes developed more fine roots(diameter<0.2 mm) than the inefficient ones. Both fine root count and root surface area were found to be the best parameters to portray K stress in rice. In accordance with the root morphology,higher K concentrations were noted in shoots of the efficient genotypes when grown at moderate and deficient K levels,indicating that root morphology parameters are involved in root uptake for K and in the translocation of K up to shoots. K deficiency affected not only the root morphology,but also the root ultra-structure. The roots of high-efficient genotypes had stronger tolerance to K deficient stress for root membrane damage,and could maintain the developed root architecture to adapt to the low K growth medium.

Modeling Tracer Flow Characteristics in Different Types of Pores: Visualization and Mathematical Modeling

Structure of porous media and fluid distribution in rocks can significantly affect the transport characteristics during the process of microscale tracer flow.To clarify the effect of micro heterogeneity on aqueous tracer transport,this paper demonstrates microscopic experiments at pore level and proposes an improved mathematical model for tracer transport.The visualization results show a faster tracer movement into movable water than it into bound water,and quicker occupancy in flowing pores than in storage pores caused by the difference of tracer velocity.Moreover,the proposed mathematical model includes the effects of bound water and flowing porosity by applying interstitial flow velocity expression.The new model also distinguishes flowing and storage pores,accounting for different tracer transport mechanisms(dispersion,diffusion and adsorption)in different types of pores.The resulting analytical solution better matches with tracer production data than the standard model.The residual sum of squares(RSS)from the new model is 0.0005,which is 100 times smaller than the RSS from the standard model.The sensitivity analysis indicates that the dispersion coefficient and flowing porosity shows a negative correlation with the tracer breakthrough time and the increasing slope,whereas the superficial velocity and bound water saturation show a positive correlation.

Effects of Different Hormone Treatments on Rooting and Growth of Xinjiang Early-maturing Fig Cuttings

[Objectives] To find the optimal hormone and the optimal hormone concentration for promoting rooting of the fig cuttings through the different hormone treatments for cuttings of Xinjiang early-maturing figs. [Methods]Taking Xinjiang early-maturing figs of Tibet Agricultural and Animal Husbandry College as mother trees,the semi-lignified branches were cut for cuttage and the rooting status and growth under different hormone concentrations were compared. [Results]Under the different concentrations of IBA,NAA and ABT rooting powder,the rooting rate,average root length,average number of roots,seedling rate,new shoot length and germination rate of cuttings were promoted. Especially,ABT rooting powder at the concentration of 200 mg/L showed the best promotion effect. [Conclusions]It is a good choice to use ABT rooting powder with 200 mg/L concentration in the cultivation of Xinjiang early-maturing fig cuttings.

Scabrous patrinia root inhibits circulating tumor cells in differentiated thyroid carcinoma–a clinical observation

Objective To observe the clinical inhibition of circulating tumor cells(CTCs) in differentiated thyroid carcinoma(DTC) by the extract of scabrous patrinia root(Huikangling).Methods Eighty-seven DTC patients tested positive for CTCs were randomly divided into two groups; all patients were treated with oral levothyroxine sodium in accordance with the DTC endocrine inhibition treatment criteria. Patients(n = 45) in the treatment group were provided the standard endocrine therapy along with oral Huikangling(0.4 g/tablet, 0.4 g × 3/time, 3 times/day, 12 weeks). Patients(n = 42) in the control group were only provided the standard therapy. After 4 and 12 weeks, CTCs in the blood were detected by flow cytometry.Results After 4 weeks of oral Huikangling treatment, CTCs were detected in 18(40%) and 29(69%) patients in the treatment and control groups, respectively; the difference was statistically significant(χ2 = 8.49, P < 0.05). After 12 weeks, CTCs were detected in 7(15.6%) and 17(44.7%) patients in the treatment and control groups, respectively; the difference was statistically significant(χ2 = 5.68, P < 0.05). Follow-up evaluation revealed two patients with lung metastasis and one patient with bone metastasis in the control group; one patient showed lateral neck lymph node metastasis without local recurrence in the treatment group.Conclusion Huikangling treatment reduces the number of CTC-positive DTC cases; however, further studies are needed to elucidate the underlying mechanisms.

Fine Root Distribution Pattern of Different Aged Leucaena leucocephala Trees in Debris Flow Source Area in Jiangjia Gully, China

Fine root is critical to restrain soil erosion and its distribution pattern is of great influence on the restraining effects. This study studied the fine root biomass （Br） distribution of different aged Leucaena leucocephala （5, 10, 15 years） in debris flow source area in Jiangjia Gully by digging downward to the bottom at different distances to stem in three directions on slope. The results showed the Br increased dramatically by 143% from 5 years to lO years and then rose slowly by 38% from to years to 15 years. The Br of 5 years was significantly asymmetric between uphill and alonghill directions, but there was little difference among directions for other ages, and a concentration trend appeared to exist in downhill and alonghill directions. Moreover, fine root （D≤1 mm） was significantly heavier than that of fine root （1mm〈D〈2 ram）, playing a leading role in the vertical distribution of the whole fine root, with a logarithmic or an exponential function. The results presented may shed light on fine root distribution pattern and evaluation of its effect on slope stability in debris flow source area.

Interpretation on Cultural Conflicts between America and China and the Conflict Root Cause Reflected in The Joy Luck Club

This paper is mainly written to explore how cultural differences and clashes between America and China give rise to mother-daughter discords and conflicts. The paper was conducted based on the definition of culture in order to make clear of cultural conflicts. It is written to analyze the two groups of women immigrants unavoidably encountering the clash between their ancestral culture—Chinese culture and the dominant culture--American culture. Furthermore, the paper demonstrates that the mothers' Chinese roots are the root cause of misunderstandings and conflicts between their American-born daughters and themselves.Besides, the writer analyzes that different standpoints towards education value between mothers and American- born daughters cause their misunderstanding and conflicts. The conclusion is that the diversities between Chinese culture and American culture are the root cause for the mother-daughter discords and conflicts.

Flow and sound fields of scaled high-speed trains with different coach numbers running in long tunnel

Segregated incompressible large eddy simulation and acoustic perturbation equations were used to obtain the flow field and sound field of 1:25 scale trains with three,six and eight coaches in a long tunnel,and the aerodynamic results were verified by wind tunnel test with the same scale two-coach train model.Time-averaged drag coefficients of the head coach of three trains are similar,but at the tail coach of the multi-group trains it is much larger than that of the three-coach train.The eight-coach train presents the largest increment from the head coach to the tail coach in the standard deviation(STD)of aerodynamic force coefficients:0.0110 for drag coefficient(Cd),0.0198 for lift coefficient(Cl)and 0.0371 for side coef-ficient(Cs).Total sound pressure level at the bottom of multi-group trains presents a significant streamwise increase,which is different from the three-coach train.Tunnel walls affect the acoustic distribution at the bottom,only after the coach number reaches a certain value,and the streamwise increase in the sound pressure fluctuation of multi-group trains is strengthened by coach number.Fourier transform of the turbulent and sound pressures presents that coach number has little influence on the peak frequencies,but increases the sound pressure level values at the tail bogie cavities.Furthermore,different from the turbulent pressure,the first two sound pressure proper orthogonal decomposition(POD)modes in the bogie cavities contain 90%of the total energy,and the spatial distributions indicate that the acoustic distributions in the head and tail bogies are not related to coach number.

The effects of decompressive craniectomy on cerebral blood flow volume and brain metabolism in different aged patients with severe traumatic brain injury

Objective To explore effects of decompressive craniectomy on cerebral blood flow volume and brain metabolism in different aged patients with severe traumatic brain injury. Methods 71 cases were divided into three groups according age: group A( 【 30 years) ,group B ( 30 ～ 50 years) 。

Square-root divided difference Rauch-Tung-Striebel smoother

A square-root version of the divided difference Rauch-Tung-Striebel (RTS) smoother is proposed in this paper. The square-root variant essentially propagates the square roots of the covariance matrices and can consistently improve the numerical stability because all the resulting covariance matrices are guaranteed to stay positive semi-definite. Furthermore, the square-root form ensures reliable implementation in an embedded system with fixed or limited precision although it is algebraically equivalent to the standard form. The new smoothing algorithm is tested in a challenging two-dimensional maneuvering target tracking problem with unknown and time-varying turn rate, and its performance is compared with that of other de-facto standard filters and smoothers. The simulation results indicate that the proposed RTS smoother markedly outperforms the associated filters and gives slightly smaller error than an unscented-based RTS smoother.

Synthesis of an Optimal Control for Linear Stationary Discrete Dynamical Systems

In this paper, an algorithm designed by the author is used to construct the general solution to difference equations with constant coefficients. It is worth noting that the algorithm does not require any information on the multiple roots of the characteristic equation. This means one does not need to reconfigure the algorithm when changing the multiplicity groups. It is for this reason that the algorithm is called “universal”. In the present study, we solve the task of finding a linear optimal control for linear stationary discrete one- and higher-dimensional systems with scalar control. Moreover, we give analytical expressions for the control that minimize the quadratic criterion and ensure the asymptotic stability of the closed system. The obtained optimal control depends only on the parameters of the initial system and the roots of the characteristic equation.

Mechanisms for the Movement of Fe，Mn，Cn and Zn to Plant Roots in Loessal So il and Lon Soil

The pot experiments were conducted in the artificial climate laboratories to determine the relativeimportance of mass flow and diffusion in supplying Fe, Mn, Cu and Zn to wheat, soybean and maize plantsgrowing in loessal soil and lou soil. It was found that the calculated relative contribution of mass flow ofiron, manganese, copper and zinc to plant uptake varied from 5% to more than 100%,depending on the cropspecies and soil types as well as plant growth stage, soil moisture, atmosphere humidity, etc. The results alsoshowed that the major transportation mechanisms of these micronutrients in soil-root system varied with thecrop and its growth, climate and soil, significantly. In general, mass flow was more important for Cu andZn and diffusion was more significant for Fe and Mn at the seedling stage.

Aesthetic comparison between Chinese memorial poetry and western elegy

Owing to the cultural, philosophical and religious differences, Chinese memorial poetry and western elegy show different attitudes towards death and have different ways to express it. Therefore, they have different aesthetic preference to death. This paper focuses on the basic characteristics of Chinese memorial poetry and western elegy. It analyzes the causes of these differences from the aspect of the content and style, ways of expression and cultural psychology.

iRoot SP、GuttaFlow2、AH Plus根管封闭剂的临床应用比较

目的对两种常温流动根充封闭剂(硅酸钙基-iRoot SP、硅氧烷基-GuttaFlow2)结合单尖充填技术以及常用封闭剂(AH Plus)结合连续波热牙胶充填技术的短期临床效果进行评价。方法将279颗患牙(656个根管)随机分为3组,分别为iRoot SP组、GuttaFlow2组以及AH Plus组。记录每个根管的充填时间,拍数字化牙片评估每个根管的充填效果,并于术后1周及1月进行回访,记录患者的疼痛发生率。SPSS18.0对以上数据行统计学分析。结果3组的根管充填效果均无统计学差异(P>0.05);iRoot SP组与GuttaFlow2组的充填时间无显著差异(P>0.05),较AH Plus组明显缩短(P<0.05);iRoot SP组与GuttaFlow2组的术后疼痛无统计学差异(P>0.05),iRoot SP组与GuttaFlow2组均较AH Plus组疼痛发生率较低(P<0.05)。结论GuttaFlow2和iRoot SP配合单尖充填技术较常用热牙胶充填技术节省填充时间,且能获得良好的临床效果,术后疼痛发生率较低。

Effects of plant roots on soil preferential pathways and soil matrix in forest ecosystems

To characterize effects of plant roots on preferential flow（PF）,we measured root length density（RLD）and root biomass（RB） in Jiufeng National Forest Park,Beijing,China.Comparisons were made for RLD and RB between soil preferential pathways and soil matrices.RLD and RB declined with the increasing soil depth（0–10,10–20,20–30,30–40,40–50,50–60 cm） in all experimental plots.RLD was greater in soil preferential pathways than in the surrounding soil matrix and was 69.5,75.0 and72.2 % for plant roots of diameter（d） ／1,1 ／ d ／ 3 and3 ／ d ／ 5 mm,respectively.Fine root systems had the most pivotal influence on soil preferential flow in this forest ecosystem.In all experimental plots,RB content was the sum of RB from soil preferential pathways and the soil matrix in each soil depth.With respect to 6 soil depth gradient（0–10,10–20,20–30,30–40,40–50,50–60 cm） in each plot,the number of soil depth gradient that RB content was greater in soil preferential pathways than in the soil matrix was characterized,and the proportion was68.2 % in all plots.

Patterns,magnitude,and controlling factors of hydraulic redistribution of soil water by Tamarix ramosissima roots

Tamarix spp. （Saltcedar） is a facultative phreatophyte that can tolerate drought when groundwater is not accessed. In addition to deep water uptake, hydraulic redistribution （HR） is another factor contributing to the drought tolerance of Tarnarix spp. In this study, data on soil volumetric moisture content （0）, lateral root sap flow, and relevant climate variables were used to investigate the patterns, magnitude, and controlling factors of HR of soil water by roots of Tamarix ramosissima Ledeb. in an extremely arid land in Northwest China. Results showed evident diurnal fluctuations in 0 at the depths of 30 and 50 cm, indicating ＂hydraulic lift＂ （HL）. 0 increased remarkably at 10 and 140 cm but decreased at 30 and 50 cm and slightly changed at 80 cm after rainfall, suggesting a possible ＂hydraulic descent＂ （HD）. However, no direct evidence was observed in the negative flow of lateral roots, supporting HR （including HL and HD） of T. ramosissima. The HR pathway unlikely occurred via lateral roots; instead, HR possibly occurred through adventitious roots with a diameter of 2-5 mm and a length of 60-100 cm. HR at depths of 20-60 cm ranged from 0.01-1.77 mm/d with an average of 0.43 mm/d, which accounted for an average of 22% of the estimated seasonal total water depletion at 0-160 cm during the growing season. The climate factors, particularly vapor pressure deficit and soil water potential gradient, accounted for at least 33% and 45% of HR variations with depths and years, respectively. In summary, T. ramosissima can be added to the wide list of existing species involved in HR. High levels of HR may represent a considerable fraction of daily soil water depletion and substantially improve plant water status. HR could vary tremendously in terms of years and depths, and this variation could be attributed to climate factors and soil water potential gradient.

Flow difference effect in the lattice hydrodynamic model

In this paper, a new lattice hydrodynamic model based on Nagatani＇s model INagatani T 1998 Physica A 261 5991 is presented by introducing the flow difference effect. The stability condition for the new model is obtained by using the linear stability theory. The result shows that considering the flow difference effect leads to stabilization of the system compared with the original lattice hydrodynamic model. The jamming transitions among the freely moving phase, the coexisting phase, and the uniform congested phase are studied by nonlinear analysis. The modified KdV equation near the critical point is derived to describe the traffic jam, and kink -antikink soliton solutions related to the traffic density waves are obtained. The simulation results are consistent with the theoretical analysis for the new model.