To build a general model for the propagation of destructive events during disasters, we consider a networked system. The model involves network nodes as single objects and delayed interactions along directed links.
In this work, a disaster is understood as a sequence of dynamic destructive events which cause nonreversible changes, spreading in cascade-like manner. We define a global state of the system and suppose that the Markovian property holds. Hence, we can describe any object‘s first affect using the phase type distribution. This model can be used to improve disaster awareness and anticipated disaster response management. and Obsahuje seznam literatury
This study assessed the effect of leaf age on construction cost (CC) in the mangrove species Avicennia germinans, Laguncularia racemosa, and Rhizophora mangle growing in their natural habitat. Leaf osmolality values were species-specific, the highest in A. germinans (1 693 mmol kg-1) and the lowest in L. racemosa (1 270 mmol kg-1). In the three species, contents of chlorophyll (a+b) (Chla+b) and nitrogen (N) per unit of leaf area were maximal in adult leaves and tended to decline with age. Leaf mass to leaf area ratio (LMA) and ash content increased during leaf ageing. Similarly, as leaves aged, a significant increase in leaf construction cost per leaf area (CCa) was observed, while per leaf mass (CCm) it remained almost constant, suggesting a sustained production of leaf compounds as leaves became older. CC was positively correlated with LMA and heat of combustion (Hc) per leaf area, suggesting differences among species in the quantity and composition of expensive compounds. Leaf half lifetime (t0.5) showed contrasting values in the three mangrove species (60, 111, and 160 d in L. racemosa, R. mangle, and A. germinans, respectively). Overall, L. racemosa was the species with less expensive leaves to construct while leaves of A. germinans and R. mangle had the highest CCm and CCa, respectively. Leaf longevity was positively correlated with the ratio between CC and maximum photosynthetic rate (Pmax), clearly showing the existence of a balance between leaf costs and benefits.