Analysis of the relationship between sexual size dimorphism, mating system and body size in the Icterids (Icteridae)

Se realizó un análisis de la relación estudiada previamente por Webster (1992) entre dimorfismo sexual de tamaño, sistema de apareamiento y tamaño corporal de los ictéridos (Icteridae). El análisis se basó en los datos originales, pero se utilizaron contrastes filogenéticamente independientes y una nueva filogenia molecular. El dimorfismo sexual se relacionó positivamente tanto con el tamaño corporal como con el tamaño de harén de las especies. Sin embargo, la relación entre tamaño corporal y dimorfismo sexual sería el resultado de la relación entre el tama ño corporal y el grado de poliginia y entre el grado de poliginia y el dimorfismo sexual. Estos resultados concuerdan con los hallados en el estudio previo de Webster (1992).The relationship previously studied by Webster (1992) among sexual size dimorphism, mating system and body size in the icterids (Icteridae) was analyzed by using the original data, but also phylogenetically independent contrasts and a new molecular phylogeny. Sexual size dimorphism was positively related with body size as well as with harem size of the species. However, the relationship between body size and sexual dimorphism would be the result of the relationship between body size and poliginy degree and between poliginy degree and sexual dimorphism. These results agree with those found by Webster (1992)

The regular cosmic string in Born-Infeld gravity

It is shown that Born-Infeld gravity --a high energy deformation of Einstein gravity-- removes the singularities of a cosmic string. The respective vacuum solution results to be free of conical singularity and closed timelike curves. The space ends at a minimal circle where the curvature invariants vanish; but this circle cannot be reached in a finite proper time.Comment: 4 pages, submitted to Proceedings of Spanish Relativity Meeting 2010 (ERE2010, Granada, Spain

The VPN problems with concave costs

Only recently Goyal, Olver and Shepherd (Proc. STOC, 2008) proved that the symmetric Virtual Private Network Design (sVPN) problem has the tree routing property, namely, that there always exists an optimal solution to the problem whose support is a tree. Combining this with previous results by Fingerhut, Suri and Turner (J. Alg., 1997) and Gupta, Kleinberg, Kumar, Rastogi and Yener (Proc. STOC, 2001), sVPN can be solved in polynomial time. In this paper we investigate an APX-hard generalization of sVPN, where the contribution of each edge to the total cost is proportional to some non-negative, concave and non-decreasing function of the capacity reservation. We show that the tree routing property extends to the new problem, and give a constant-factor approximation algorithm for it. We also show that the undirected uncapacitated single-source minimum concave-cost flow problem has the tree routing property when the cost function has some property of symmetry

Characterization of paralic paleoenvironments using benthic foraminifera from early Cretaceous deposits (Scotian Shelf)

Abstrac

Identification of Measurement Points for Calibration of Water Distribution Network Models

AbstractMuch importance is given to determining the input data for water distribution system networks, particularly with regard to urban networks, because the design and the management of WDS are based on a verification model. Good calibration of models is required to obtain realistic results. This is possible by the use of a certain number of measurements: flow in pipes and pressure in nodes. The purpose of this paper is to analyze a new model able to provide guidance on the choice of measurement points to obtain the site data. All analyses are carried out firstly on literature networks and then on a real network using a new approach based on sensitivity matrices

emergency management of water distribution systems the nodal demand control

Abstract During emergency situations (e.g., due to pipe bursts or other network failures), appropriate management of Water Distribution Systems (WDS) is required. Critical events often cause service failures, because the pressure head in some nodes of the network become inadequate to deliver required demand. In this paper, a new methodology is developed based on the nodal demand control. with the aim to increase the pressure head, and hence the flow rate actually delivered at critical nodes (i.e., hospitals, vulnerable customers, etc.). This is done to avoid or minimize service interruptions between the failure and the repair times. Furthermore, a pipe burst can cause isolation of a portion of the network such that the flow along pipes changes and this causes the reduction of head in some nodes. The proposed methodology is manages the delivered flow rate using a Pressure Driven Analysis (PDA) approach. This is based on operating control of valves and by identifying the nodes where the pressure control should be implemented. Those control nodes are chosen by the analysis of sensitivity matrices and the Max-Sum Method (Bush and Uber, 1998; Fiorini Morosini et al., 2014). The methodology is demonstrated on a case study for a real network of Cosenza, a town in the South of Italy