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Radiocarbon dating of fossil bats from Dobšina Ice Cave (Slovakia) and potential palaeoclimatic implications

Gradziński M., Hercman H., Peresviet-Soltan A., Zelinka J., Jelonek M.

Annales Societatis Geologorum Poloniae

2016

Vol. 86, No. 3

341--350

Although Dobšina Ice Cave (DIC, Carpathians, Slovakia) is located outside the high-mountain area, it hosts one of the most extensive blocks of perennial subterranean ice, the volume of which is estimated at more than 110,000 m3. Frozen bat remains were found in the lowermost part of the perennial ice block. They belong to Myotis blythii (Tomes) and the M. mystacinus morpho-group. The radiocarbon dating of bat soft tissues yielded ages of 1266–1074 cal. yr BP and 1173–969 cal. yr BP. The undetermined bat, found in the same part of the ice section in 2002, was previously dated at 1178–988 cal. yr BP (Clausen et al., 2007). The dates testify that the ice crystallized at the turn of the Dark Ages Cold Period and the Medieval Warm Period. The calculated accumulation rate of cave ice varies between 0.7 cm/year and 1.4 cm/year at that time, and is similar to the present ice accumulation rate in DIC. Constant crystallization of ice during the Medieval Warm Period is hypothesized to reflect dry summer seasons since the supply of relatively warm water in the summer is one of the key factors causing the erosion of cave ice. The uppermost sample was covered with 20.6 m of ice. Between ca 1065 cal. yr BP and the present day, the ice grew faster than between ca 1210 yr BP and ca 1065 yr BP by a factor of 1.3–1.8. This may have resulted from conditions favourable for ice accumulation during the Little Ice Age.

Agent-based approach to illegal maritime behavior modeling

Hrstka O., Vaňek O., Kopřiva Š., Zelinka J., Faigl J., Pěchouček M.

Zeszyty Naukowe Akademii Morskiej w Szczecinie

2015

nr 42 (114)

101--111

Maritime shipping is a set of complex activities with a large number of actors involved. We focus on a subset of illegal maritime activities, such as armed robberies, maritime piracy or contraband smuggling. To fight against them and minimize their negative impact naval authorities typically introduce a number of countermeasures, such as deployed patrols or surveillance agents. Due to very high costs of countermeasures it is often beneficial to evaluate their impact using a simulation, allowing what-if analysis and evaluation of a range of scenarios before actually deploying the countermeasures. We introduce BANDIT, an agent-based computational platform, which is designed to evaluate scenarios with an accent on the modeling of different types of illegal behavior and on the interaction between agents. The platform consists of an agent behavior modeling system and a multi-agent maritime simulator. The platform allows the definition of a number of scenarios through a simple configuration and it offers the means to run these scenarios in a single or a batch mode and evaluate the results as single or aggregate data sets respectively. We demonstrate the usefulness of the platform on the scenarios of the drug smuggling problem in the seas surrounding Central America. Senario outcomes (e.g., heatmaps of activities, set of trajectories etc.) are subsequently used to help with the design of effective countermeasures, i.e., allocating naval patrols and planning their patrol routes.