Browsing Articles publicats (Matemàtica) by Title
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Limit cycles bifurcating from planar polynomial quasihomogeneous centers
(Elsevier, 2015)In this paper we find an upper bound for the maximum number of limit cycles bifurcating from the periodic orbits of any planar polynomial quasihomogeneous center, which can be obtained using first order averaging method. ... 
Limits of the Linear Accumulation Regime of DGT Sensors
(American Chemical Society, 2013)A key question for the practical application of DGT (Diffusive Gradients in Thin films) as dynamic sensors in the environmental monitoring of trace metals is the influence of pH and dissolved ligands over the linear ... 
Looking back over their shoulders: a qualitative analysis of portuguese teachers' attitudes towards statistics
(International Association for Statistical Education, 2012)Teachers’ attitudes towards statistics can have a significant effect on their own statistical training, their teaching of statistics, and the future attitudes of their students. The influence of attitudes in teaching ... 
Magic coverings and the Kronecker product
(2014)In this paper we study a relationship existing among (super) magic coverings and the well known Kronecker product of matrices. We also introduce the concept of Znproperty for digraphs in order to study this relation ... 
Mixed Moore Cayley graphs
(Elsevier, 20140901)Cayley graphs are well known objects with interesting properties, also in the context of Moore graphs and digraphs. In $1978$ Bos\'ak extended Moore's property to the mixed setting (with arcs allowed along with edges), in ... 
Mobile terrestrial laser scanner applications in precision fruticulture/ horticulture and tools to extract information from canopy point clouds
(Springer Science+Business Media, 20170101)LiDAR sensors are widely used in many areas and, in recent years, that includes agricultural tasks. In this work, a selfdeveloped mobile terrestrial laser scanner based on a 2D light detection and ranging (LiDAR) sensor ... 
Modeling tactical planning decisions through a linear optimization model in sow farms
(Elsevier, 2012)This paper deals with tactical planning decisions for breeding farms producing piglets through a linear optimization model. A mediumterm planning horizon based on weekly periods is considered. The proposed model maximizes ... 
Modeling the consequences of the demise and potential recovery of a keystonespecies: wild rabbits and avian scavengers in Mediterranean landscapes
(Nature Publishing Group, 2015)Restoration of demised keystonespecies populations is an overriding concern in conservation biology. However, since no population is independent of its environment, progress is needed in predicting the efficacy of restoration ... 
Modelling the effects of sanitary policies on European vulture conservation
(Nature Publishing Group, 2012)Biodiversity losses are increasing as a consequence of negative anthropogenic effects on ecosystem dynamics. However, the magnitude and complexity of these effects may still be greatly underestimated. Most Old World ... 
Modified inertia from extended uncertainty principle(s) and its relation to MoND
(Springer, 2020)In this paper we show that Modified Inertia, i.e., the modification of inertia predicted by some alternative theories of gravity at cosmic scales, can be naturally derived within the framework of the extended uncertainty ... 
Modified inertial mass from information loss
(World Scientific Publishing, 2017)A modification of inertia (called MiHsC or quantized inertia) has been proposed that assumes that inertia is caused by Unruh radiation, and that this radiation is made inhomogeneous in space by either Rindler horizons ... 
New MooreLike Bounds and Some Optimal Families of Abelian Cayley Mixed Graphs
(20200606)Mixed graphs can be seen as digraphs that have both arcs and edges (or digons, that is, two opposite arcs). In this paper, we consider the case where such graphs are Cayley graphs of abelian groups. Such groups can be ... 
New problems related to the valences of (super) edgemagic labelings
(2013)A graph G of order p and size q is edgemagic if there is a bijective function f : V (G) ∪ E(G) −→ {i} p+q i=1 such that f(x) + f(xy) + f(y) = k , for all xy ∈ E(G) . The function f is an edgemagic labeling of G and the ... 
Nilpotent centres via inverse integrating factors
(Cambridge University Press, 201610)In this paper we are interested in the nilpotent center problem of planar analytic monodromic vector fields. It is known that the formal integrability is not enough to characterize such centers. More general objects are ... 
Non existence of almost Moore digraphs of diameter three
(Electronic Journal of Combinatorics, 2008)Almost Moore digraphs appear in the context of the degree/diameter problem as a class of extremal directed graphs, in the sense that their order is one less than the unattainable Moore bound M(d; k) = 1 + d + + dk, where ... 
Nonexistence of limit cycles for planar vector fields
(Texas State University. Department of Mathematics, 2014)This article presents sufficient conditions for the nonexistence of limit cycles for planar vector fields. Classical methods for the nonexistence of limit cycles are connected with the theory developed here. 
Nonsmooth quadratic centers defined in two arbitrary sectors
(Elsevier, 20161125)In this paper we analyze the centerfocus problem of some families of piecewise planar quadratic vector fields on two zones of R2. The zones we consider are two unbounded sectors defined by an arbitrary angle α and a fixed ... 
Nondegenerate centers for Abel polynomial differential equations of second kind
(Elsevier, 2017)In this paper we study the center problem for Abel polynomial differential equations of second kind. Computing the focal values and using modular arithmetics and Gröbner bases we find the center conditions for such systems ... 
Numerical Simulation of NonLinear Models of Reaction—Diffusion for a DGT Sensor
(MDPI, 20200420)In this work, we present a novel strategy for the numerical solution of a coupled system of partial differential equations that describe reaction–diffusion processes of a mixture of metals and ligands that can be absorbed ... 
On bipartitemixed graphs
(Wiley, 20180404)Mixed graphs can be seen as digraphs that have both arcs and edges (or digons, that is, two opposite arcs). In this arti cle, we consider the case where such graphs are bipartite. As main results, we show that in this ...