Optimization of the management of platelet concentrate stocks in the Basque Country using mathematical simulation

Background and Objectives: The management of platelet concentrate (PC) stocks is not simple given their short shelf life and variable demand. In general, managers decide on PC production based on personal experience. The objective of this study was to provide a tool to help decide how many PC units to produce each day in a more rational and objective way. Materials and Methods: From the historical data on PCs produced, transfused and discarded in the Basque Country in 2012, a mathematical model was built, based on the normality of the time series of the transfusions performed on each day of the week throughout the year. This model was implemented in an easy-to-use Excel spreadsheet and validated using real production data from 2013. Results: Comparing with real 2013 data, in the best scenario, the number of PC units that expired was 87·7% lower, PC production, 14·3% lower and the age of the PCs transfused nearly 1-day younger in the simulation. If we want to ensure a minimum stock at the end of each day, the outdating rate and average age of the transfused PCs progressively increase. Conclusion: The practical application of the designed tool can facilitate decision-making about how many PC units to produce each day, resulting in very significant reductions in PC production and wastage and corresponding cost savings, together with an almost 1 day decrease in the mean age of PCs transfused

On the nonlinear stability of mKdV breathers

A mathematical proof for the stability of mKdV breathers is announced. This proof involves the existence of a nonlinear equation satisfied by all breather profiles, and a new Lyapunov functional which controls the dynamics of small perturbations and instability modes. In order to construct such a functional, we work in a subspace of the energy one. However, our proof introduces new ideas in order to attack the corresponding stability problem in the energy space. Some remarks about the sine-Gordon case are also considered.Comment: 7 p

Kink propagation in a two-dimensional curved Josephson junction

We consider the propagation of sine-Gordon kinks in a planar curved strip as a model of nonlinear wave propagation in curved wave guides. The homogeneous Neumann transverse boundary conditions, in the curvilinear coordinates, allow to assume a homogeneous kink solution. Using a simple collective variable approach based on the kink coordinate, we show that curved regions act as potential barriers for the wave and determine the threshold velocity for the kink to cross. The analysis is confirmed by numerical solution of the 2D sine-Gordon equation.Comment: 8 pages, 4 figures (2 in color

Energy localization and shape transformations in semiflexible polymer rings

Shape transformations in driven and damped molecular chains are considered. Closed chains of weakly coupled molecular subunits under the action of spatially homogeneous time-periodic external field are studied. The coupling between the internal excitations and the bending degrees of freedom of the chain modifies the local bending rigidity of the chain. In the absence of driving the array takes a circular shape.When the energy pumped into the system exceeds some critical value the chain undergoes a nonequilibrium phase transition: The circular shape of the aggregate becomes unstable and the chain takes the shape of an ellipse or, in general, of a polygon. The excitation energy distribution becomes spatially nonuniform: It localizes in such places where the chain is more flat. The weak interaction of the chain with a flat surface restricts the dynamics to a flat manifold.Y.B.G. acknowledges partial financial support from a special program of the National Academy of Sciences of Ukraine, and is thankful to the Department of Applied Mathematics and Computer Science and the Department of Physics, Technical University of Denmark as well as the University of Seville for hospitality. J.F.R.A acknowledges Grant No. 2011/FQM-280 from CEICE, Junta de Andalucia Spain. J.F.R.A. and V.J.S.-M. acknowledge financial support from Project No. FIS2015-65998-C2-2-P from MINECO, Spain.Gaididei, YB.; Archilla, JFR.; Sánchez Morcillo, VJ.; Gorria, C. (2016). Energy localization and shape transformations in semiflexible polymer rings. Physical Review E. 93(6):062227-1-062227-9. https://doi.org/10.1103/PhysRevE.93.062227S062227-1062227-993

Size-induced superantiferromagnetism with reentrant spin-glass behavior in metallic nanoparticles of TbCu2

An unusual 4f -superantiferromagnetic state characterized by simultaneous antiferromagnetic and spin-glass behaviors induced by particle-size reduction is revealed in metallic nanoparticles (≈ 9 nm) of TbCu 2 . The Néel temperature is 46 K and the glassy freezing is below ≈ 9 K and governed by a critical slowing down process. Neutron diffraction at 1.8 K establishes the superantiferromagnetism. The latter is settled by the nanoparticle moments and the freezing mechanism is provided by the surface spins

High-magnetic field characterization of magnetocaloric effect in FeZrB(Cu) amorphous ribbons

"The magnetic and magnetocaloric properties of a series of Fe-rich FeZrB(Cu) amorphous ribbons were investigated under magnetic field values up to mu H-0 of 8 T. A correlation between the saturation magnetization and the maximum magnetic entropy change vertical bar Delta S-M(peak)vertical bar is clearly evidenced. Although these metallic glasses show relatively low vertical bar Delta S-M(peak)vertical bar values (from 3.6 to 4.4 J kg(-1) K-1 for mu(0)Delta H - 8 T), the Delta S-M(T) curve broadens upon the increase in mu(0)Delta H, giving rise to a large refrigerant capacity RC (above 900 J kg(-1) for mu(0)Delta H-8 T). Using the universal curve method for rescaling the Delta S-M(T, mu(0)Delta H) curves, we found a collapse of the curves around the Curie temperature. However, in the low-temperature range the curves do not match into a single one due to the existence of magnetic frustration.