Seedling potential of trees species along the elevational gradient in temperate hill forest of central Nepal

Regeneration status of tree species along elevation gradient in temperate hill forest was not understood greatly.Present research examined the tree diversity and its regeneration patterns along an elevation gradient in temperate hill forest,central Nepal.Data were collected from 300 sample plots within vertical elevation bands of 10,ranging from 1365 to 2450 m asl.A random sampling method was used for data collection in three seasons,winter,pre-monsoon and post monsoon seasons.Diameter at breast height(DBH)was used to broadly categorize the plant individual into trees,saplings and seedlings.The tree species richness ranged from 12 to 25 with density of 350 to 1200 individuals per hectare.Species richness of tree and sapling showed statistically significant unimodal pattern,which peaked at mid-elevation.Elevation showed a strong and positive linear correlation with the seedling density(Deviance=0.99,p<0.001)and a significant hump-shaped relationship with sapling density(Deviance=0.95,p<0.001).Similarly,elevations showed a statistically significant negative hump-shaped relationship with all trees,saplings and seedling stages(Deviances=0.89,0.87 and 0.57).The highest values of the Shannon-Wiener index and the lowest value of the Simpson index were found at mid-elevation for all growth forms.Nearly 92%of tree species were found at regenerating stage;49%in a good renewal regeneration status,32%in fair renewal regeneration,and 11%at a poor regenerating condition.Nevertheless,4%of tree species were reported as non-regenerating stages and 4%were newly introduced species.Hence,the regeneration status of the study area was considered fairly well since sapling(78.5%)>seedling(10.6%)≤mature(10.9%).Among tested environmental variables,elevation and annual mean rainfall were the most influential factors in the regeneration of tree species.

THE GRADIENT ESTIMATE OF SUBELLIPTIC HARMONIC MAPS WITH A POTENTIAL

In this paper,we investigate subelliptic harmonic maps with a potential from noncompact complete sub-Riemannian manifolds corresponding to totally geodesic Riemannian foliations.Under some suitable conditions,we give the gradient estimates of these maps and establish a Liouville type result.

Extreme Cold Events in North America and Eurasia in November-December 2022: A Potential Vorticity Gradient Perspective

From 17 November to 27 December 2022, extremely cold snowstorms frequently swept across North America and Eurasia. Diagnostic analysis reveals that these extreme cold events were closely related to the establishment of blocking circulations. Alaska Blocking(AB) and subsequent Ural Blocking(UB) episodes are linked to the phase transition of the North Atlantic Oscillation(NAO) and represent the main atmospheric regimes in the Northern Hemisphere. The downstream dispersion and propagation of Rossby wave packets from Alaska to East Asia provide a large-scale connection between AB and UB episodes. Based on the nonlinear multi-scale interaction(NMI) model, we found that the meridional potential vorticity gradient(PVy) in November and December of 2022 was anomalously weak in the mid-high latitudes from North America to Eurasia and provided a favorable background for the prolonged maintenance of UB and AB events and the generation of associated severe extreme snowstorms. However, the difference in the UB in terms of its persistence,location, and strength between November and December is related to the positive(negative) NAO in November(December). During the La Ni?a winter of 2022, the UB and AB events are related to the downward propagation of stratospheric anomalies, in addition to contributions by La Ni?a and low Arctic sea ice concentrations as they pertain to reducing PVyin mid-latitudes.

Two Dimensional Cahn-Hilliard Equation with Concentration Dependent Mobility and Gradient Dependent Potential

In this paper we consider the initial boundary value problem of Cahn-Hilliard equation with concentration dependent mobility and gradient dependent potential. By the L^P type estimates and the theory of Morrey spaces,we prove the Holder continuity of the solutions.Then we obtain the existence of global classical solutions.The present work can be viewed as an extension to the previous work on the Cahn-Hilliard equation with concentration dependent mobility and potential.

Structural Setting of the South-West Cameroon Using Satellite Potential Field Derived from SGG-UGM-2 Gravity Data

This study aims to improve knowledge of the structure of southwest Cameroon based on the analysis and interpretation of gravity data derived from the SGG-UGM-2 model. A residual anomaly map was first calculated from the Bouguer anomaly map, which is strongly affected by a regional gradient. The residual anomaly map generated provides information on the variation in subsurface density, but does not provide sufficient information, hence the interest in using filtering with the aim of highlighting the structures affecting the area of south-west Cameroon. Three interpretation methods were used: vertical gradient, horizontal gradient coupled with upward continuation and Euler deconvolution. The application of these treatments enabled us to map a large number of gravimetric lineaments materializing density discontinuities. These lineaments are organized along main preferential directions: NW-SE, NNE-SSW, ENE-WSW and secondary directions: NNW-SSE, NE-SW, NS and E-W. Euler solutions indicate depths of up to 7337 m. Thanks to the results of this research, significant information has been acquired, contributing to a deeper understanding of the structural composition of the study area. The resulting structural map vividly illustrates the major tectonic events that shaped the geological framework of the study area. It also serves as a guide for prospecting subsurface resources (water and hydrocarbons). .

Changes of plasma membrane ATPase activity, membrane potential and transmembrane proton gradient in Kandelia candel and Avicennia marina seedlings with various salinities

The salt-secreting mangrove, Avicennia marina, and non-salt-secreting mangrove, Kandelia candel were cultivated in sand with various salinities(0‰, 10‰, 20‰, 30‰, 40‰) for 60 d. Plasma membrane vesicles of high-purity in leaves and roots of A.marina and K. candel seedlings were obtained by two-phase partitioning. The function of the plasma membranes, the activity of ATPase, membrane potential and transmembrane proton gradient, at various salinities were investigated. The results showed that within a certain range of salinity(A. marina and roots of K. candel: 0—30‰; leaves of K.candel: 0—20‰), the activity of ATPase increased with increasing salinity, while high salinity(above 30‰ or 20‰) inhibited ATPase activity. In comparison with A. marina, K. candel appeared to be more sensitive to salinity. The dynamics of membrane potential and transmembrane proton gradient in leaves and roots of A. marina and K. candel seedlings were similar to that of ATPase. When treated directly by NaCl all the indexes were inhibited markedly: there was a little increase within 0—10‰(K. candel) or 0—20‰(A. marina) followed by sharp declining. It indicated that the structure and function of plasma membrane was damaged severely.

Fabrication of ZnO-based thick film varistors with high potential gradient

ZnO-based thick film varistors have been fabricated by Y203 doping and low-temperature sintering, of which the sample with the best electrical properties has a high potential gradient value of 3159.4 V/mm. The effects of Y2O3 doping concentration and sintering temperature on the potential gradient of the samples were systematically investigated. The results show that the sample with the best electrical properties can be obtained by doping 0.08 mol% Y2O3 and sintering at 725℃. Under these optimum preparation conditions, the leakage current and the nonlinear coefficient are found to be 36.4 gA and 13.1. The sample with the best electrical properties has a grain size of 1.290um, a single grain boundary voltage of 4.08 V, a barrier height of 0.81 eV, and a depletion layer width of 10.2 nm, which are determined by thermionic emission. Small grain size with good grain boundary characteristics is beneficial to improve the electrical properties of varistors and promote the potential gradient.

Effects of La^(3+)on H^+ Transmembrane Gradient and Membrane Potential in Rice Seedling Roots

The effects of LaCl 3 on membrane potential and transmembrane proton gradient for rice ( Oryza sativa ) seedling roots were studied. Highly purified plasma membrane was isolated by aqueous two phase partitioning method. Both the gradient of transmembrane proton and membrane potential were stimulated by certain low concentration of LaCl 3 and depressed by high concentration of LaCl 3. The optimal concentration of La 3+ is around 40～60 μmol·L -1 for transmembrane proton gradient and membrane potential. It shows that La 3+ can influence the generations and maintenances of membrane potential and transmembrane proton gradient in rice seedling roots.

Bound State Solutions of Schrodinger Equation for Generalized Morse Potential with Position-Dependent Mass

The effective mass one-dimensional Schroedinger equation for the generalized Morse potential is solved by using Nikiforov-Uvarov method. Energy eigenvalues and corresponding eigenfunctions are computed analytically. The results are also reduced to the constant mass case. Energy eigenvalues are computed numerically for some diatomic molecules. They are in agreement with the ones obtained before.

Analysis of localized shear deformation of ductile metal based on gradient-dependent plasticity

Shear localization in linear strain softening heterogeneous material under simple shear was investigated analytically. The closed-form solutions obtained based on gradient plasticity theory considering interactions and interplaying among microstructures due to heterogeneity of metal material show that in the normal direction of shear band, elastic shear displacement is linear; while plastic and total shear displacement are non-linear. Elastic shear strain in the band is uniform and the non-uniformity of total shear displacement stems from localized plastic shear displacement. In the center of the band, plastic and total shear displacement all reach their maximum values. In strain-softening process, elastic displacement decreases as flow shear stress decreases. Contrarily, plastic and total shear displacement increase and manifest shear localization occurs progressively. Under the same shear stress level, plastic and total shear displacement increase as strain softening modulus and elastic shear modulus decrease. The present analytical solutions were compared with many experimental results and the agreement is good.

ANALYSIS OF SIZE EFFECT,SHEAR DEFORMATION AND DILATION IN DIRECT SHEAR TEST BASED ON GRADIENT- DEPENDENT PLASTICITY

The paper concerns the issue of size law,localized deformation and dilation or compaction due to shear localization. It is assumed that the shear localization initiates at the peak shear stress in the form of single shear band,and based on gradient-dependent plasticity,an analytical solution on size effect or snap-back is obtained. The results show that the post peak response becomes steeper and even exhibits snap-back with increasing of length. For small specimen,the relative shear displacement when specimen failure occurs is lower than that of larger specimen and the shear stress-relative displacement curve becomes steeper. The theoretical solution on non-uniformity of strains in shear band is obtained and evolution of the relative shear displacement is represented. By resorting to the linear relation between local plastic shear strain and local plastic volumetric strain,the dilation and compaction within shear band are analyzed. Relation between apparent shear strain and apparent normal strain and relation between shear displacement and vertical displacement are established.

Calculation of temperature distribution in adiabatic shear band based on gradient-dependent plasticity

A method for calculation of temperature distribution in adiabatic shear band is proposed in terms of gradient-dependent plasticity where the characteristic length describes the interactions and interplaying among microstructures. First, the increment of the plastic shear strain distribution in adiabatic shear band is obtained based on gradient-dependent plasticity. Then, the plastic work distribution is derived according to the current flow shear stress and the obtained increment of plastic shear strain distribution. In the light of the well-known assumption that 90% of plastic work is converted into the heat resulting in increase in temperature in adiabatic shear band, the increment of the temperature distribution is presented. Next, the average temperature increment in the shear band is calculated to compute the change in flow shear stress due to the thermal softening effect. After the actual flow shear stress considering the thermal softening effect is obtained according to the Johnson-Cook constitutive relation, the increment of the plastic shear strain distribution, the plastic work and the temperature in the next time step are recalculated until the total time is consumed. Summing the temperature distribution leads to rise in the total temperature distribution. The present calculated maximum temperature in adiabatic shear band in titanium agrees with the experimental observations. Moreover, the temperature profiles for different flow shear stresses are qualitatively consistent with experimental and numerical results. Effects of some related parameters on the temperature distribution are also predicted.

Adiabatic shear localization evolution for steel based on the Johnson-Cook model and gradient-dependent plasticity

Gradient-dependent plasticity is introduced into the phenomenological Johnson-Cook model to study the effects of strainhardening, strain rate sensitivity, thermal-softening, and microstructure. The microstructural effect （interactions and interplay among microstructures） due to heterogeneity of texture plays an important role in the process of development or evolution of an adiabatic shear band with a certain thickness depending on the grain diameter. The distributed plastic shear strain and deformation in the shear band are derived and depend on the critical plastic shear strain corresponding to the peak flow shear stress, the coordinate or position, the internal length parameter, and the average plastic shear strain or the flow shear stress. The critical plastic shear strain, the distributed plastic shear strain, and deformation in the shear band are numerically predicted for a kind of steel deformed at a constant shear strain rate. Beyond the peak shear stress, the local plastic shear strain in the shear band is highly nonuniform and the local plastic shear deformation in the band is highly nonlinear. Shear localization is more apparent with the increase of the average plastic shear strain. The calculated distributions of the local plastic shear strain and deformation agree with the previous numerical and experimental results.

INVESTIGATION ON GRADIENT-DEPENDENT NONLOCAL CONSTITUTIVE MODELS FOR ELASTO-PLASTICITY COUPLED WITH DAMAGE

Firstly, typical) gradient-dependent nonlocal inelastic models were briefly reviewed. Secondly, based on the principle of ‘gradient-dependent energy dissipation', a gradient-dependent constitutive model for plasticity coupled with isotropic damage was presented in the framework of continuum thermodynamics. Numerical scheme for calculation of Laplacian term of damage field with the numerical results obtained by FEM calculation was proposed. Equations have been presented on the basis of Taylor series for both 2-dimensional and 3-dimensional cases, respectively. Numerical results have indicated the validity of the proposed gradient-dependent model and corresponding numerical scheme.

Momentum Eigensolutions of Feinberg-Horodecki Equation with Time-Dependent Screened Kratzer-Hellmann Potential

We obtain an approximate value of the quantized momentum eigenvalues, Pn, together with the space-like coherent eigenvectors for the space-like counterpart of the Schrödinger equation, the Feinberg-Horodecki equation, with a screened Kratzer-Hellmann potential which is constructed by the temporal counterpart of the spatial form of this potential. In addition, we got exact eigenvalues of the momentum and the eigenstates by solving Feinberg-Horodecki equation with Kratzer potential. The present work is illustrated with three special cases of the screened Kratzer-Hellman potential: the time-dependent screened Kratzer potential, time-dependent Hellmann potential and, the time-dependent screened Coulomb potential.

Control of soliton characteristics of the condensate by an arbitrary x-dependent external potential

This paper presents a family of soliton solutions of the one-dimensional nonlinear Schrodinger equation which describes the dynamics of the dark solitons in Bose-Einstein condensates with an arbitrary x-dependent external potential. The obtained results show that the external potential has an important effect on the dark soliton dynamical characteristics of the condensates. The amplitude, width, and velocity of the output soliton are relative to the source position of the external potential. The smaller the amplitude of the soliton is, the narrower its width is, and the slower the soiiton propagates. The collision of two dark solitons is nearly elastic .

Direct evidence for dynamics of cell heterogeneity in watercored apples: turgor-associated metabolic modifications and within-fruit water potential gradient unveiled by single-cell analyses

Watercore is a physiological disorder in apple(Malus×domestica Borkh.)fruits that appears as water-soaked tissues adjacent to the vascular core,although there is little information on what exactly occurs at cell level in the watercored apples,particularly from the viewpoint of cell water relations.By combining picolitre pressure-probe electrospray-ionization mass spectrometry(picoPPESI-MS)with freezing point osmometry and vapor pressure osmometry,changes in cell water status and metabolisms were spatially assayed in the same fruit.In the watercored fruit,total soluble solid was lower in the watercore region than the normal outer parenchyma region,but there was no spatial difference in the osmotic potentials determined with freezing point osmometry.Importantly,a disagreement between the osmotic potentials determined with two methods has been observed in the watercore region,indicating the presence of significant volatile compounds in the cellular fluids collected.In the watercored fruit,cell turgor varied across flesh,and a steeper water potential gradient has been established from the normal outer parenchyma region to the watercore region,retaining the potential to transport water to the watercore region.Site-specific analysis using picoPPESI-MS revealed that together with a reduction in turgor,remarkable metabolic modifications through fermentation have occurred at the border,inducing greater production of watercore-related volatile compounds,such as alcohols and esters,compared with other regions.Because alcohols including ethanol have low reflection coefficients,it is very likely that these molecules would have rapidly penetrated membranes to accumulate in apoplast to fill.In addition to the water potential gradient detected here,this would physically contribute to the appearance with high tissue transparency and changes in colour differences.Therefore,it is concluded that these spatial changes in cell water relations are closely associated with watercore symptoms as well as with metabolic alterations.

GIS-Mapping of Soil Available Plant Nutrients (Potentiality, Gradient, Anisotropy)

The research was elaborated in Kafr El-Dawar area (Egypt northern region) to study the availability of the soil plant nutrients. The research introduced three parameters to comprehensively and carefully describe the availability of the soil plant nutrients: potentiality, gradient and anisotropy. Potentiality defines the categories of soil ability to supply plant nutrients;meanwhile gradient expresses the increasing rate of the availability of the soil plant nutrients. The gradient anisotropy refers to the directions or orientation of the increasing rate of the availability of the soil plant nutrients. The introduced parameters enabled to spatially study the availability of the soil plant nutrients. Analytical data, of soil available phosphorus (P), indicated that P ranged from 0.2 ppm to 11.4 ppm to locate all studied soil samples into the low class of the soil nutritional P ability. This was not the case of available potassium (K), where the soil samples were distributed into three available K soil categories: medium, high, and very high. GIS map of soil P nutritional potentiality for plant (potato), displayed the soil studied area in one category, as low P soil nutritional potentiality to coincide with the analytical data classification. Contrary, the K map classified the soil studied area into three categories of soil K nutritional potentiality: medium, high and excessive. This obviously referred that the individual determination of soil K nutritional potentiality is misleading for interpretation of soil tests because it does care of the spatial distribution of soil available K. Nearly, all soil samples had high available micronutrients that they were located in the high category in both classification of analytical data and GIS maps. GIS gradient maps of the soil available plant nutrients referred that the soil plant nutrients, exception of K, had two gradients: non increasing-slight increasing and build up. Gradient of soil available potassium was classified into four classes: non increasing-slight increasing, build up, moderately increasing and hike. Regardless potassium case, the non increasing-slight increasing gradient class dominated the others. GIS maps of anisotropy soil availability of macronutrients (P and K) generally showed that their gradients mainly increased in two directions: north and south. The incasing directions of soil availability of micronutrients coincided with that of the macronutrients.

From Gradient Elasticity to Gradient Interatomic Potentials: The Case-Study of Gradient London Potential

Motivated by the special theory of gradient elasticity (GradEla), a proposal is advanced for extending it to construct gradient models for interatomic potentials, commonly used in atomistic simulations. Our focus is on London’s quantum mechanical potential which is an analytical expression valid until a certain characteristic distance where “attractive” molecular interactions change character and become “repulsive” and cannot be described by the classical form of London’s potential. It turns out that the suggested internal length gradient (ILG) generalization of London’s potential generates both an “attractive” and a “repulsive” branch, and by adjusting the corresponding gradient parameters, the behavior of the empirical Lennard-Jones potentials is theoretically captured.

Determination of Photon and Elementary Particles Rest Masses Using Maxwell’s Equations and Generalized Potential Dependent Special Relativity

The nature and origin of the photon and elementary rest masses are some of the challeng-ing problems that physics face. The approaches used to solve these problems are complex and time-consuming. Specifically, the photon rest mass pays attention to theoretical physi-cists. Many experimental works show that the photon rest mass is non zero. This problem can be solved using generalized potential dependent special relativity, which has been de-rived using simple arguments, and Maxwell’s equations, besides the conventional Einstein energy-momentum relation. The results obtained show that the rest mass of photons and elementary particles are strongly dependent on the vacuum energy and a universal con-stant. This result conforms with the models that predict time decaying vacuum energy as-sociated with production of smaller rest mass particles followed by larger masses. The two potential dependent mass expressions conform with the cosmological models that suggest the photon is generated first by assuming the universe consisting of total constant vacuum with decaying cosmological part and mass generating part. Using Maxwell’s equations, beside plank and De Broglie hypothesis together with special relativity energy-momentum relation the photon rest mass is estimated. It was shown that the photon rest mass is ex-tremely small compared to the electron mass.