Communities in DSpace
Select a community to browse its collections.
Recent Submissions
Flood projections for selected Costa Rican main basins using CMIP6 climate models downscaled output in the HBV hydrological model for scenario SSP5-8.5
(2024) Hidalgo León, Hugo G.; Alfaro Martínez, Eric J.; Quesada Román, Adolfo
Estimates from 3 statistically downscaled General Circulation Models (GCMs) from version 6 of the Coupled Model Intercomparison Project, namely the EC Earth3, GFDL ESM4 and MPI ESM1 2 HR are used in the HBV hydrological model to estimate design streamflow projections with 20, 50, and 100-year return periods for the selected main basins of Costa Rica. The changes in these streamflows were computed between the baseline period (1985–2015) and the mid-century projection (2035–2065) for the SSP5-8.5 scenario. The novelty resides in being the first study that explores the magnitude of climate changes in design flows of Costa Rica, a tropical country. Although, calibration and validation statistics are generally good for most of the basins, only around one quarter of the simulations reproduce the observed distribution of the 3-day annual maximum flows. Results show that the MPI model presents lower sensitivity with changes of different sign depending on the basin studied and the other two models suggest only significant increases in the design flow in most of the basins. Results of the model’s ensemble suggests a great concern, as there is a general increase in the design flows, and the magnitudes of the changes are large, especially in the Pacific slope.
The Dewar forms of furan, thiophene and pyrrole
(1985-10-21) Strausz, Otto P.; Rendall, W.A.; Torres, M.; Constenla Umaña, Manuel Arturo
Text regarding the Dewar forms of furan, triophene and pyrrole.
On the dynamics of a quadratic Schrödinger system in dimension n = 5
(2018-10-02) Noguera Salgado, Norman F.; Pastor Ferreira, Ademir
In this work we give a sharp criterion for the global well-posedness, in the energy space, for a system of nonlinear Schr¨odinger equations with quadratic interaction in dimension n = 5. The criterion is given in terms of the charge and energy of the ground states associated with the system, which are obtained by minimizing a Weinstein-type functional. The main result is then obtained in view of a sharp Gagliardo-Nirenberg-type inequality.
Pre-service teachers' understanding of the derivative of a function at a point
(2021-08-13) Vargas González, María Fernanda; Fernández Plaza, José Antonio; Ruiz Hidalgo, Juan Francisco
This article aims to delve into the meaning of school mathematical concepts by their semantic analysis. Concretely, this paper aimed primarily to describe and characterize the meaning of derivative of a function at a point expressed by mathematics pre-service teachers. In order to achieve this goal, we use a semantic framework, in which the meaning is composed of: (a) conceptual structure, (b) representation systems, and (c) sense and usage. This qualitative, descriptive study analysed the replies of 37 pre-service teachers to questions involving the definition, requirements, and structural concept of derivatives. It also explores the sense and usage attributed by participants to this mathematical concept. At least five profiles of meanings for derivatives could be constructed from the results. The most prominent findings included the prevalence of the geometric interpretation of the concept and participants’ failure to mention elements and requisites essential to the definition of derivatives.
Scattering for quadratic-type Schrödinger systems in dimension five without mass-resonance
(2021-08-11) Noguera Salgado, Norman F.; Pastor Ferreira, Ademir
In this paper we study the scattering of non-radial solutions in the energy space to coupled system of nonlinear Schrödinger equations with quadratic-type growth interactions in dimension five without the mass-resonance condition. Our approach is based on the recent technique introduced by Dodson and Murphy (Math Res Lett 25:1805–1825, 2018), which relies on an interaction Morawetz estimate. It is proved that any solution below the ground states scatters in time.