65 research outputs found
Seismic hazard in Nicaragua: a case study of Managua
Nicaragua, país centroamericano de 6.2 millones de habitantes, conocido por sus grandes lagos y volcanes activos, se encuentra en el cinturón de fuego del Pacífico, en la zona de subducción de la Placa Coco bajo la Placa Caribe. El país tiene un amplio historial de destrucción causado por sucesivos terremotos de fuerte magnitud. Centenas de fallas geológicas causan sismos frecuentes en la capital, Managua. El propósito de este trabajo es analizar el caso singular de Managua y su alto riesgo de sufrir pérdidas y daños por desastres naturales catastróficos, presentando para eso, el escenario tectónico-volcánico del país; el estudio se enfoca en los episodios más extremos ocurridos, analizando la amenaza sísmica en Managua. Como resultado de este trabajo se entrega un panorama general de los tipos de amenazas geológicas que desafían Nicaragua, concentrándose en las amenazas sísmicas y algunos episodios trágicos en el historial de desastres naturales geológicos, contribuyendo así con la difusión de conocimientos necesarios al planteamiento de políticas de mitigación y prevención de desastres geológicos sísmicos y volcánicos.Nicaragua, Central American country of 6.2 million people, is known for its large lakes and active volcanoes. Yet, the country has a long history of destruction caused by successive strong earthquakes, due to its location on the Pacific Ring of Fire in the subduction zone of the Cocos plate under the Caribbean plate. As such, Managua, the capitol, with 1.480.000 million inhabitants, is the most susceptible area to disasters, as a result of hundreds of faults that cause frequent earthquakes. The purpose of this paper is to analyze the risks that the city of Managua faces of suffering material and human losses, in the event of an extreme natural disaster, by describing the tectonic-volcanic conditions of the country, taking as theoretical reference the concepts of natural hazards and natural disasters. The empirical section analyzes data from Nicaraguan scientific institutes and specialized literature, from which an overview of the types of geological hazards that prevail in the country is laid out. By focusing on seismic hazards and on some tragic episodes in the history of geological disasters,the paper aims to contribute to the current body of knowledge necessary for the definition of mitigation and prevention policies of seismic and volcanic geological disasters
Doubly Periodic Instanton Zero Modes
Fermionic zero modes associated with doubly periodic SU(2) instantons of unit
charge are considered. In cases where the action density exhibits two
`instanton cores' the zero mode peaks on one of four line-segments joining the
two constituents. Which of the four possibilities is realised depends on the
fermionic boundary conditions; doubly periodic, doubly anti-periodic or mixed.Comment: 12 pages, 4 figure
ADHM Construction of Instantons on the Torus
We apply the ADHM instanton construction to SU(2) gauge theory on T^n x
R^(4-n)for n=1,2,3,4. To do this we regard instantons on T^n x R^(4-n) as
periodic (modulo gauge transformations) instantons on R^4. Since the R^4
topological charge of such instantons is infinite the ADHM algebra takes place
on an infinite dimensional linear space. The ADHM matrix M is related to a Weyl
operator (with a self-dual background) on the dual torus tilde T^n. We
construct the Weyl operator corresponding to the one-instantons on T^n x
R^(4-n). In order to derive the self-dual potential on T^n x R^(4-n) it is
necessary to solve a specific Weyl equation. This is a variant of the Nahm
transformation. In the case n=2 (i.e. T^2 x R^2) we essentially have an
Aharonov Bohm problem on tilde T^2. In the one-instanton sector we find that
the scale parameter, lambda, is bounded above, (lambda)^2 tv<4 pi, tv being the
volume of the dual torus tilde T^2.Comment: 35 pages, LATeX. New section on Nahm transform included, presentation
improved, reference added, to appear in Nuclear Physics
Macroecological links between the Linnean, Wallacean, and Darwinian shortfalls
Species are the currency of most biodiversity studies. However, many shortfalls and biases remain in our
biodiversity estimates, preventing a comprehensive understanding of the eco-evolutionary processes that
have shaped the biodiversity currently available on Earth. Biased biodiversity estimates also jeopardize the effective implementation of data-driven conservation strategies, ultimately leading to biodiversity loss. Here, we delve into the concept of the Latitudinal Taxonomy Gradient (LTG) and show how this new idea provides an interesting conceptual link between the Linnean (i.e., our ignorance of how many species there are on Earth), Darwinian (i.e., our ignorance of species evolutionary relationships), and Wallacean (i.e., our ignorance on species distribution) shortfalls. More specifically, we contribute to an improved understanding of LTGs and establish the basis for the development of new methods that allow us to: (i) better account for the integration between different shortfalls and, (ii) estimate how these interactions may affect our understanding about the evolutionary components of richness gradients at macroecological scales.This manuscript is partially derived from a working group on âBiodiversity Shortfallsâ held in November
2019 and sponsored by the National Institutes for Science and Technology (INCT) in Ecology, Evolution, and
Biodiversity Conservation (CNPq proc. 465610/2014-5 and FAPEG proc. 201810267000023). JJMG and LEF are supported by Ph.D. and M.Sc. scholarships from CAPES, while LM and RBP are supported by postdoctoral
fellowships from CAPES (PNPD). JS was funded by the funded by the European Unionâs Horizon 2020
research and innovation programme under the Marie SkĆodowska-Curie Action (grant agreement #843234;
project: TAXON-TIME) and by the Spanish Council for Scientific Research (IF_ERC). GT and LJ are supported
by a DTI fellowships from CNPq, while JAFD-F, LGL, and CJBC are supported by Productivity Grants from CNPq.Peer reviewe
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