Társadalmi konfliktusokat generáló ökológiai történések a Balaton életében az utóbbi néhány évtizedben – Halpusztulások

Social Conflict Generating Ecological Developments in the Life of Lake Balaton in Recent Decades – Mass Fish Kills In this paper we summed up the history and causes of the mass fish kill events documented at Lake Balaton during the last 50 years. The first catastrophic fish kill (resulting in 500 t dead fish) was caused by the leaching of PCBs used on the catchment area of the lake in 1965. From the 1970s to the end of the ’90s, in parallel with the increasing eutrophication fish kills became more frequent, which impacted the whole fish fauna and spread over the lake. In the last years with the ongoing oligotrophication the mass kills terminated. Only sporadic species specific deaths were registered.Social Conflict Generating Ecological Developments in the Life of Lake Balaton in Recent Decades – Mass Fish Kills In this paper we summed up the history and causes of the mass fish kill events documented at Lake Balaton during the last 50 years. The first catastrophic fish kill (resulting in 500 t dead fish) was caused by the leaching of PCBs used on the catchment area of the lake in 1965. From the 1970s to the end of the ’90s, in parallel with the increasing eutrophication fish kills became more frequent, which impacted the whole fish fauna and spread over the lake. In the last years with the ongoing oligotrophication the mass kills terminated. Only sporadic species specific deaths were registered

Társadalmi konfliktusokat generáló ökológiai történések a Balaton életében az utóbbi néhány évtizedben – A halfogás csökkenése

Social Conflict Generating Ecological Developments in the Life of Lake Balaton in Recent Decades – Decreasing Fish Catches The fisheries sector was the chief utilizer of fish stocks living in the Lake Balaton for centuries, however with recreational use in the forefront the importance of angling has considerably increased in the last sixty years. Due to the diminishing of spawning areas of native fish species, the unadvised stocking of non native ones (silver carp, eel), and the ongoing oligotrophication during the last fifteen years the fish stock size and composition of the lake has changed significantly. Decreasing fish catches and contrasting intrests generate numerous conflicts between fishermen and recreational anglers.Social Conflict Generating Ecological Developments in the Life of Lake Balaton in Recent Decades – Decreasing Fish Catches The fisheries sector was the chief utilizer of fish stocks living in the Lake Balaton for centuries, however with recreational use in the forefront the importance of angling has considerably increased in the last sixty years. Due to the diminishing of spawning areas of native fish species, the unadvised stocking of non native ones (silver carp, eel), and the ongoing oligotrophication during the last fifteen years the fish stock size and composition of the lake has changed significantly. Decreasing fish catches and contrasting intrests generate numerous conflicts between fishermen and recreational anglers

The contact binary VW Cephei revisited: surface activity and period variation

Context. Despite the fact that VW Cephei is one of the well-studied contact binaries in the literature, there is no fully consistent model available that can explain every observed property of this system. Aims. Our motivation is to obtain new spectra along with photometric measurements, to analyze what kind of changes may have happened in the system in the past two decades, and to propose new ideas for explaining them. Methods. For the period analysis we determined 10 new times of minima from our light curves, and constructed a new O$-$C diagram of the system. Radial velocities of the components were determined using the cross-correlation technique. The light curves and radial velocities were modelled simultaneously with the PHOEBE code. All observed spectra were compared to synthetic spectra and equivalent widths of the H$\alpha$ line were measured on their differences. Results. We have re-determined the physical parameters of the system according to our new light curve and spectral models. We confirm that the primary component is more active than the secondary, and there is a correlation between spottedness and the chromospheric activity. We propose that flip-flop phenomenon occurring on the primary component could be a possible explanation of the observed nature of the activity. To explain the period variation of VW Cep, we test two previously suggested scenarios: presence of a fourth body in the system, and the Applegate-mechanism caused by periodic magnetic activity. We conclude that although none of these mechanisms can be ruled out entirely, the available data suggest that mass transfer with a slowly decreasing rate gives the most likely explanation for the period variation of VW Cep.Comment: 13 pages, 18 figures, 9 tables, accepted for publication in Astronomy and Astrophysic

Factors shaping the composition of the cutaneous microbiota

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Multiphysical computations of the electrical machines using FEM

In this paper three problems representing the multiphysical aspect of electrical machine computation are addressed. The interaction between magnetic and structural mechanical systems is demonstrated by the finite element method (FEM) structural investigation of the turbo-generator end-winding deformations. Multiphysical simulation of the acoustical problem is presented by weakly coupled electromagnetic, structural dynamic and acoustic simulations. And finally, a procedure based on computational fluid dynamics (CFD) simulation for acquiring the convective heat transfer coefficients is proposed in order to improve the accuracy of the coupled electro-thermal FEM simulations