Lagos urbanos: importancia, dinamismo y multiplicidad de usos: el caso del lago Villa Dalcar (Córdoba, Argentina)

Urban lakes are environments with structural and functional features quite different from common lakes. This study aims to present the main results related to the environmental status of Villa Dalcar lake (33°06’25”S, 64°22’31”W, 7 ha), located in the city of Río Cuarto (Córdoba). In this lake, diverse activities as swimming, boating (including motorboat competitions), recreational and for human consumption fishing, removal of bait fish, research and teaching are usually performed. The lake also provides habitat for at least 16 fish species and other communities. However, there has been a significant conflict about the use of water, landscape contamination, fish mortality and different expressions of the trophic state, which was manifested by periods of clear and turbid waters. Different management measures were implemented to control aquatic macrophytes, such as mechanical removal, biomanipulation with fish using Ctenopharyngodon idella and dredging. The results have been variable depending on: the abundance of cyprinids, the activities developed in the basin and the fluctuations in water volume. The lake is a challenge as far as handling is concerned and the latter depends on a number of environmental, social and even political factors.Instituto de Limnología "Raúl A. Ringuelet

Lagos urbanos: importancia, dinamismo y multiplicidad de usos: el caso del lago Villa Dalcar (Córdoba, Argentina)

Urban lakes are environments with structural and functional features quite different from common lakes. This study aims to present the main results related to the environmental status of Villa Dalcar lake (33°06’25”S, 64°22’31”W, 7 ha), located in the city of Río Cuarto (Córdoba). In this lake, diverse activities as swimming, boating (including motorboat competitions), recreational and for human consumption fishing, removal of bait fish, research and teaching are usually performed. The lake also provides habitat for at least 16 fish species and other communities. However, there has been a significant conflict about the use of water, landscape contamination, fish mortality and different expressions of the trophic state, which was manifested by periods of clear and turbid waters. Different management measures were implemented to control aquatic macrophytes, such as mechanical removal, biomanipulation with fish using Ctenopharyngodon idella and dredging. The results have been variable depending on: the abundance of cyprinids, the activities developed in the basin and the fluctuations in water volume. The lake is a challenge as far as handling is concerned and the latter depends on a number of environmental, social and even political factors.Instituto de Limnología "Raúl A. Ringuelet

Lagos urbanos: importancia, dinamismo y multiplicidad de usos: el caso del lago Villa Dalcar (Córdoba, Argentina)

Urban lakes are environments with structural and functional features quite different from common lakes. This study aims to present the main results related to the environmental status of Villa Dalcar lake (33°06’25”S, 64°22’31”W, 7 ha), located in the city of Río Cuarto (Córdoba). In this lake, diverse activities as swimming, boating (including motorboat competitions), recreational and for human consumption fishing, removal of bait fish, research and teaching are usually performed. The lake also provides habitat for at least 16 fish species and other communities. However, there has been a significant conflict about the use of water, landscape contamination, fish mortality and different expressions of the trophic state, which was manifested by periods of clear and turbid waters. Different management measures were implemented to control aquatic macrophytes, such as mechanical removal, biomanipulation with fish using Ctenopharyngodon idella and dredging. The results have been variable depending on: the abundance of cyprinids, the activities developed in the basin and the fluctuations in water volume. The lake is a challenge as far as handling is concerned and the latter depends on a number of environmental, social and even political factors.Instituto de Limnología "Raúl A. Ringuelet

The Semi-Chiral Quotient, Hyperkahler Manifolds and T-duality

We study the construction of generalized Kahler manifolds, described purely in terms of N=(2,2) semichiral superfields, by a quotient using the semichiral vector multiplet. Despite the presence of a b-field in these models, we show that the quotient of a hyperkahler manifold is hyperkahler, as in the usual hyperkahler quotient. Thus, quotient manifolds with torsion cannot be constructed by this method. Nonetheless, this method does give a new description of hyperkahler manifolds in terms of two-dimensional N=(2,2) gauged non-linear sigma models involving semichiral superfields and the semichiral vector multiplet. We give two examples: Eguchi-Hanson and Taub-NUT. By T-duality, this gives new gauged linear sigma models describing the T-dual of Eguchi-Hanson and NS5-branes. We also clarify some aspects of T-duality relating these models to N=(4,4) models for chiral/twisted-chiral fields and comment briefly on more general quotients that can give rise to torsion and give an example.Comment: 31 page

Semichiral fields on S^2 and generalized Kahler geometry

Abstract: We study a class of two-dimensional N=(2,2) supersymmetric gauge theories, given by semichiral multiplets coupled to the usual vector multiplet. In the UV, these theories are traditional gauge theories deformed by a gauged Wess-Zumino term. In the IR, they give rise to nonlinear sigma models on noncompact generalized K\ue4hler manifolds, which contain a three-form field H and whose metric is not K\ue4hler. We place these theories on S2 and compute their partition function exactly with localization techniques. We find that the contribution of instantons to the partition function that we define is insensitive to the deformation, and discuss our results from the point of view of the generalized K\ue4hler target space. \ua9 2016, The Author(s)

A simulated annealing based genetic local search algorithm for multi-objective multicast routing problems

This paper presents a new hybrid evolutionary algorithm to solve multi-objective multicast routing problems in telecommunication networks. The algorithm combines simulated annealing based strategies and a genetic local search, aiming at a more flexible and effective exploration and exploitation in the search space of the complex problem to find more non-dominated solutions in the Pareto Front. Due to the complex structure of the multicast tree, crossover and mutation operators have been specifically devised concerning the features and constraints in the problem. A new adaptive mutation probability based on simulated annealing is proposed in the hybrid algorithm to adaptively adjust the mutation rate according to the fitness of the new solution against the average quality of the current population during the evolution procedure. Two simulated annealing based search direction tuning strategies are applied to improve the efficiency and effectiveness of the hybrid evolutionary algorithm. Simulations have been carried out on some benchmark multi-objective multicast routing instances and a large amount of random networks with five real world objectives including cost, delay, link utilisations, average delay and delay variation in telecommunication networks. Experimental results demonstrate that both the simulated annealing based strategies and the genetic local search within the proposed multi-objective algorithm, compared with other multi-objective evolutionary algorithms, can efficiently identify high quality non-dominated solution set for multi-objective multicast routing problems and outperform other conventional multi-objective evolutionary algorithms in the literature

Supersymmetric black hole non-uniqueness in five dimensions

We present a systematic study of the moduli space of asymptotically flat, supersymmetric and biaxisymmetric black hole solutions to five-dimensional minimal supergravity. Previously, it has been shown that such solutions must be multi-centred solutions with a Gibbons-Hawking base. In this paper we perform a full analysis of three-centred solutions with a single black hole, for which there are seven regular black hole solutions. We find that four of these can have the same conserved charges as the BMPV black hole. These consist of a black lens with L(3,1) horizon topology and three distinct families of spherical black holes with nontrivial topology outside the horizon. The former provides the first example of a nonspherical black hole with the same conserved charges as the BMPV black hole. Moreover, of these four solutions, three can have a greater entropy than the BMPV black hole near the BMPV upper spin bound. One of these is a previously known spherical black hole with nontrivial topology and the other two are new examples of a spherical black hole with nontrivial topology and an L(3,1) black lens.Comment: version 2: typos corrected, minor clarifications added; 26 pages, 10 figure

Rotating black hole entropy from M5-branes

We compute the superconformal index of 3d N = 2 superconformal field theories obtained from N M5-branes wrapped on a hyperbolic 3-manifold. Exploiting the 3d-3d correspondence, we use perturbative invariants of SL(N, \u2102) Chern-Simons theory to determine the superconformal index in the large N limit, including corrections logarithmic in N. The leading order partition function provides a microscopic foundation for the entropy function of the dual rotating asymptotically AdS4 black holes. We also verify that the supergravity one-loop contribution to the log N term coincides with the field theoretic result. We propose a 3d-3d formulation for the refined topologically twisted index, and provide strong evidence in support of its vanishing \u2014 which agrees with the fact that the expected dual rotating magnetically-charged black hole does not exist. This provides an interesting link between gravity and a tantalizing mathematical result