The eccentricity of a vertex v of a connected graph G is the distance from v to a vertex farthest from v in G. The center of G is the subgraph of G induced by the vertices having minimum eccentricity. For a vertex v in a 2-edge-connected graph G, the edge-deleted eccentricity of v is defined to be the maximum eccentricity of v in G − e over all edges e of G. The edge-deleted center of G is the subgraph induced by those vertices of G having minimum edge-deleted eccentricity. The edge-deleted central appendage number of a graph G is the minimum difference |V (H)| − |V (G)| over all graphs H where the edgedeleted center of H is isomorphic to G. In this paper, we determine the edge-deleted central appendage number of all trees.
This paper presents a case study for the strength demonstration of a railway wagon welded node using the probability approach. The design variables were taken from the existing standardization for railway vehicles. The fatigue damage summation method for proving the satisfactory service life as well as the Goodman diagram method for verification of the unlimited service life was used for the node examination. The probability estimation was made using the Monte Carlo SBRA method with the help of the Anthill software. and Obsahuje seznam literatury
Acclimation to irradiance was investigated in seedlings of Japanese beech {Fagus crenata Bl.) grown under one of five irradiance regimes for three years. Inadiance (/) regimes covered the range of environmental conditions which this species normally would experience in Japanese beech forests: exposed [22.1 mol(quantum) m‘2 d'*, matching mean daily irradiance of exposed canopies], partially shaded [8.8, 2.7 and 1.5 mol(quantum) d'*, respectively, comparable to various midcanopies], and deeply shaded [0.5 mol(quantum) nu^ d"', equivalent to forest floor], There were consistent strong relationships between irradiance, growth performance and net photosynthetic rate (P^) for this species. Greater growth performance and were achieved as / increased, with aboveground height growth increasing as rapidly as basal diameter growth. This tiend was also observed in the leaf specific mass and leaf nitrogen content. Exposed plants had higher saturation I for (> 1400 |amol m'^ s‘*) than partially shaded plants (1180, 1100 and 753 pmol m‘2 s'', respectively). Higher leaf conductance, leaf specific mass and leaf nitrogen content correlated positively with higher Nevertheless, the beech seedlings adapted to deep shade by producing more total chlorophyll and requiring lower compensation / (Qq) at lower growth irradiances. Seedlings of Japanese beech were very tolerant to shade but capable of acclimating to strong I. Thus / is an important factor influencing growth and photosynthetic capacity of Japanese beech.
The Loess Plateau is the main source of water in Yellow River, China. After 1980s, the Yellow river water presented a significant reduction, what caused the decrease of the Yellow river discharge had been debated in academic circles. We proceeded with runoff generation mechanisms to explain this phenomenon. We built saturation excess runoff and infiltration excess runoff generation mechanisms for rainfall–runoff simulation in Jingle sub-basin of Fen River basin on the Loess Plateau, to reveal the influence of land use change on flood processes and studied the changes of model parameters under different underlying conditions. The results showed that the runoff generation mechanism was mainly infiltration-excess overland flow, but the flood events of saturation-excess overland flow had an increasing trend because of land use cover change (the increase of forestland and grassland areas and the reduction of cultivated land). Some of the model parameters had physical significances，such as water storage capacity (WM), infiltration capacity (f), evapotranspiration (CKE), soil permeability coefficient (k) and index of storage capacity distribution curve (n) showed increasing trends, and index of infiltration capacity distribution curve (m) showed a decreasing trend. The above results proved the changes of runoff generation mechanism from the perspective of model parameters in Jingle sub-basin, which can provide a new perspective for understanding the discharge reduction in the Yellow River basin.