Time filter

Source Type

Slupsk, Poland

Ozgo M.,Pomeranian University | Schilthuizen M.,Netherlands Center for Biodiversity Naturalis | Schilthuizen M.,University of Groningen
Global Change Biology | Year: 2012

We compared shell colour forms in the land snail Cepaea nemoralis at 16 sites in a 7 × 8 km section of the Province of Groningen, the Netherlands, between 1967 and 2010. To do so, we used stored samples in a natural history collection and resampled the exact collection localities. We found that almost all populations had experienced considerable evolutionary change in various phenotypes, possibly due to population bottlenecks and habitat change after repeated land consolidation schemes in the area. More importantly, we found a consistent increase in yellow effectively unbanded snails at the expense of brown snails. This is one of the expected adaptations to climate change (this area of the Netherlands has warmed by 1.5-2.0 °C over the time period spanned by the two sampling years), and the first clear demonstration of this in C. nemoralis. © 2011 Blackwell Publishing Ltd.

Frackiewicz P.,Pomeranian University
Journal of Physics A: Mathematical and Theoretical | Year: 2013

The Marinatto-Weber approach to quantum games is a straightforward way to apply the power of quantum mechanics to classical game theory. In the simplest case, the quantum scheme is that players manipulate their own qubits of a twoqubit state either with the identity 1 or the Pauli operator σx. However, such a simplification of the scheme raises doubt as to whether it could really reflect a quantum game. In this paper we put forward examples which may constitute arguments against the present form of the Marinatto-Weber scheme. Next, we modify the scheme to eliminate the undesirable properties of the protocol by extending the players' strategy sets. © 2013 IOP Publishing Ltd.

Obolewski K.,Pomeranian University
Ecological Engineering | Year: 2011

Hydrological connectivity and the frequency and intensity of floods are the key factors determining the structure of macroinvertebrates inhabiting wetland ecosystems in river valleys. In 2007, water and macroinvertebrate samples were collected on four occasions in the middle course of the Słupia River and in five oxbow lakes (Northern Poland) to determine the hydrological relations in a regulated lowland river environment marked by a moderate climate. The water bodies selected for the study featured different types of connections with the main river valley: two of them were completely cut off from the valley, one was connected via a single branch, one featured a forced-flow connection through drainage pipes, and one was connected by a system of drainage channels. Macroinvertebrates, mostly Chironomidae larvae, were predominant in the eutrophic waters of the river. The prevalent macroinvertebrates found in the eutrophicated oxbow lakes isolated from the river were Chironomidae larvae and Crustacea (mainly Asellus aquaticus). In unobstructed oxbow lakes, the main component of benthic fauna was Crustacea, while Ephemeroptera were found mostly in the water body connected to the river via a drainage channel. A canonical correspondence analysis (CCA) showed that hydrological connectivity was the main factor responsible for the structure of invertebrate populations, followed by the physical and chemical parameters of the local environment. A non-conformance analysis revealed that hydrological connectivity enhanced invertebrate abundance and biological diversity, while the overall abundance was marked by unimodal distribution. The developed general model indicates that in the group of measured environmental variables, nitrite concentrations were highly correlated with Shannon diversity and invertebrate composition, while sulphate levels were closely associated with invertebrate abundance in the waters of the analyzed ecosystems. © 2010 Elsevier B.V.

Frackiewicz P.,Pomeranian University
Journal of Physics A: Mathematical and Theoretical | Year: 2014

We present a quantum approach to a signaling game; a special kind of extensive game of incomplete information. Our model is based on quantum schemes for games in strategic form where players perform unitary operators on their own qubits of some fixed initial state and the payoff function is given by a measurement on the resulting final state. We show that the quantum game induced by our scheme coincides with a signaling game as a special case and outputs nonclassical results in general. As an example, we consider a quantum extension of the signaling game in which the chance move is a three-parameter unitary operator whereas the players' actions are equivalent to classical ones. In this case, we study the game in terms of Nash equilibria and refine the pure Nash equilibria adapting to the quantum game the notion of a weak perfect Bayesian equilibrium. © 2014 IOP Publishing Ltd.

Majewski M.,Pomeranian University
Quaternary International | Year: 2014

A survey of the Lake Jasień area (northern Poland) demonstrates the relationship between human economic activity and the course of slopewash processes during the Subatlantic. In the catchment area of the erosional-denudational valley affected by prolonged human economic activity in the early Iron Age (the Hallstatt period) and the pre-Roman period, deforestation may have led to activation of hillslope processes. A manifestation of this activation is a fossil cut in the bottom of the valley and sediments of hillslope origin filling it, lying on top of sediments dated to 450 BC-100cal. AD. The intensity of the hillslope processes may have been modelled by climate changes involving cooling and humidification.The most recent documented increase in the intensity of denudation occurred around the middle of the 17th century. Deposited on top of sediments dated to 1456 AD-1638cal. AD and 1453 AD-1797cal. AD is a sequence of hillslope sediments developed in the form of diluvium and tillage diamicton filling the bottom of the valley and the closed depression.Faster denudation in the landform catchments and accumulation on their bottoms were caused by deforestation of those areas and using them as farmland, as indicated by old cartographic materials. The cooling and humidification of the climate during the Little Ice Age may also have contributed to the acceleration of the agrotechnical denudation. In areas unaffected by deforestation, no noticeable traces have been found of active denudation processes during the Subatlantic. This may suggest that hillslope processes did not play a major role in lowland forested areas of the Temperate Zone. © 2013 Elsevier Ltd and INQUA.

Discover hidden collaborations