Efecto de la interacción ola-corriente en la propagación de la marea en estuarios

[ES] En este artículo se analiza, mediante un modelo numérico, el efecto de la interacción ola-corriente en la propagación de la onda de marea en el interior de los estuarios. En concreto, se estudia la influencia de diferentes campos de oleaje incidentes en la desembocadura sobre la propagación de la onda de marea a lo largo del estuario. Los resultados obtenidos muestran que en los estuarios cuya desembocadura está sometida a la incidencia de oleaje relativamente energético, la onda de marea sufre un efecto similar a lo que produciría un aumento de la rugosidad o longitud del estuario. Más aún, aunque el oleaje se disipe totalmente en la zona más cercana a la desembocadura, sus efectos se hacen notables a lo largo de todo el estuario. Estas alteraciones en la propagación de la onda de marea tienen importantes implicaciones en la morfología de los estuarios, tanto a corto como a medio y largo plazo. Consecuentemente, modificaciones en las condiciones de oleaje en las zonas exteriores de los estuarios (construcción de diques de abrigo, espigones de canalización, etc.) conllevan variaciones en la morfología general interior de los mismos.Olabarrieta, M.; Medina, R.; Lomónaco Tonda, P. (2005). Efecto de la interacción ola-corriente en la propagación de la marea en estuarios. Ingeniería del agua. 12(4):329-344. https://doi.org/10.4995/ia.2005.2569OJS32934412

Spectral Theory for Perturbed Krein Laplacians in Nonsmooth Domains

We study spectral properties for $H_{K,\Omega}$, the Krein--von Neumann extension of the perturbed Laplacian $-\Delta+V$ defined on $C^\infty_0(\Omega)$, where $V$ is measurable, bounded and nonnegative, in a bounded open set $\Omega\subset\mathbb{R}^n$ belonging to a class of nonsmooth domains which contains all convex domains, along with all domains of class $C^{1,r}$, $r>1/2$. In particular, in the aforementioned context we establish the Weyl asymptotic formula #\{j\in\mathbb{N} | \lambda_{K,\Omega,j}\leq\lambda\} = (2\pi)^{-n} v_n |\Omega| \lambda^{n/2}+O\big(\lambda^{(n-(1/2))/2}\big) {as} \lambda\to\infty, where $v_n=\pi^{n/2}/ \Gamma((n/2)+1)$ denotes the volume of the unit ball in $\mathbb{R}^n$, and $\lambda_{K,\Omega,j}$, $j\in\mathbb{N}$, are the non-zero eigenvalues of $H_{K,\Omega}$, listed in increasing order according to their multiplicities. We prove this formula by showing that the perturbed Krein Laplacian (i.e., the Krein--von Neumann extension of $-\Delta+V$ defined on $C^\infty_0(\Omega)$) is spectrally equivalent to the buckling of a clamped plate problem, and using an abstract result of Kozlov from the mid 1980's. Our work builds on that of Grubb in the early 1980's, who has considered similar issues for elliptic operators in smooth domains, and shows that the question posed by Alonso and Simon in 1980 pertaining to the validity of the above Weyl asymptotic formula continues to have an affirmative answer in this nonsmooth setting.Comment: 60 page

A global agenda for advancing freshwater biodiversity research

Global freshwater biodiversity is declining dramatically, and meeting the challenges of this crisis requires bold goals and the mobilisation of substantial resources. While the reasons are varied, investments in both research and conservation of freshwater biodiversity lag far behind those in the terrestrial and marine realms. Inspired by a global consultation, we identify 15 pressing priority needs, grouped into five research areas, in an effort to support informed stewardship of freshwater biodiversity. The proposed agenda aims to advance freshwater biodiversity research globally as a critical step in improving coordinated actions towards its sustainable management and conservation

A global agenda for advancing freshwater biodiversity research

This manuscript is a contribution of the Alliance for Freshwater Life (www.allianceforfreshwaterlife.org). We thank Nick Bond, Lisa Bossenbroek, Lekima Copeland, Dean Jacobsen, Maria Cecilia Londo?o, David Lopez, Jaime Ricardo Garcia Marquez, Ketlhatlogile Mosepele, Nunia Thomas-Moko, Qiwei Wei and the authors of Living Waters: A Research Agenda for the Biodiversity of Inland and Coastal Waters for their contributions. We also thank Peter Thrall, Ian Harrison and two anonymous referees for their valuable comments that helped improve the manuscript. Open access funding enabled and organised by Projekt DEAL

A global agenda for advancing freshwater biodiversity research

Global freshwater biodiversity is declining dramatically, and meeting the challenges of this crisis requires bold goals and the mobilisation of substantial resources. While the reasons are varied, investments in both research and conservation of freshwater biodiversity lag far behind those in the terrestrial and marine realms. Inspired by a global consultation, we identify 15 pressing priority needs, grouped into five research areas, in an effort to support informed stewardship of freshwater biodiversity. The proposed agenda aims to advance freshwater biodiversity research globally as a critical step in improving coordinated actions towards its sustainable management and conservation.Peer reviewe