Implications of within-period timing in models of speculative attack

Speculative attacks are often modeled as decreases in money demand before currency crises. I discuss how, in models with microfoundations, within-period timing affects whether attacks arise in equilibrium. “Cash-when-I'm-done†timing always generates attacks, but is controversial because it assumes that end-of-period money balances buy current consumption. Cash-in-advance timing, theoretically more appealing, generates attacks only under restrictive assumptions. These issues arise when money is introduced via liquidity constraints, the utility function, or a transactions technology. Modeling attacks via reductions in demand for domestic bonds, instead of reductions in money demand, helps avoid these issues, and may be more realistic.

Shear tardihercynian zones in the Central part of the Gredos Sierra (Spanish Central Range)

[Resumen] En este trabajo, se exponen las principales conclusiones alcanzadas en nuestra Tesis Doctoral (DOBLAS, M., 1989), en cuanto a la historia deformativa del sector central de la Sierra de Gredos para tiempos tardihercínicos, distinguiéndose tres episodios tectónicos dentro de un marco geotectónico global, durante los cuales se generan diferentes familias de zonas de cizalla: 1) Un primer episodio caracterizado por un regimen extensional con un eje de esfuerzos a 1 subvertical, que denominamos «Episodio Dúctil Extensional Tardihercínico» (DETH); 2) Un segundo episodio, caracterizado por un régimen transcurrente dúctil, con un eje de esfuerzos a 1 de direcci6n EW, que denominamos «Episodio Dúctil Transcurrente Tardihercínico» (D1TH); y, 3) Un tercer y último evento, bajo un régimen transcurrente frágil, con un eje de esfuerzos a 1 según NS, que denominamos Episodio Frágil Transcurrente Tardihercínico» (FfTH).[Abstract] This paper presents the main conclusions reached in our Doctoral Thesis (DOBLAS, M., 1989), regarding the deformational history of the central part of the Gredos Sierra for the tardihercynian time-span, during which three tectonics events, might be distinguished within a generalizated geotectonic frame, with different sets of shear zones: 1) A first extensional event with a subvenical a 1 stress axis, termed «Ductile Extensional Tardihercynian Event» (DETH); 2) A second episode characterized by transcurrent tectonics within a ductile regime, with an EW-oriented a 1 stress axis, termed «Ductile Transcurrent Tardihercynian Event» (D1TH); and, 3) A last event with brittle transcurrent faults, with a NS-oriented a 1 axis, termed «Brittle Transcurrent Tardihercynian Event» (FfTH)

Observed modes of sea surface temperature variability in the South Pacific region

The South Pacific (SP) region exerts large control on the climate of the Southern Hemisphere at many times scales. This paper identifies the main modes of interannual sea surface temperature (SST) variability in the SP which consist of a tropical-driven mode related to a horseshoe structure of positive/negative SST anomalies within midlatitudes and highly correlated to ENSO and Interdecadal Pacific Oscillation (IPO) variability, and another mode mostly confined to extratropical latitudes which is characterized by zonal propagation of SST anomalies within the South Pacific Gyre. Both modes are associated with temperature and rainfall anomalies over the continental regions of the Southern Hemisphere. Besides the leading mode which is related to well known warmer/cooler and drier/moister conditions due to its relationship with ENSO and the IPO, an inspection of the extratropical mode indicates that it is associated with distinct patterns of sea level pressure and surface temperature advection. These relationships are used here as plausible and partial explanations to the observed warming trend observed within the Southern Hemisphere during the last decades.The authors would like to thank Scott Power for his comments on an earlier version of the manuscript and the two anonymous reviewers whose suggestions led to a substantial improvement of the paper. This study was supported by Grants UBACyT-20020100100803, UBACyT-20020120300051, PIP-11220120100586 and the SPECS (GA 308378) EU-funded Project. JG-S was partially supported by the H2020-funded MSCA-IF-EF DPETNA project (GA No. 655339). The authors acknowledge the Red Española de Supercomputación (RES) and PRACE for awarding access to MareNostrum 3 at the Barcelona Supercomputing Center through the HiResClim project. The support of Virginie Guémas and Oriol Mula-Valls at the Barcelona Supercomputing Center is warmly appreciated.Peer ReviewedPostprint (author's final draft

Linking the anomaly initialization approach to the mapping paradigm: a proof-of-concept study

Seasonal-to-decadal predictions are initialized using observations of the present climatic state in full field initialization (FFI). Such model integrations undergo a drift toward the model attractor due to model deficiencies that incur a bias in the model. The anomaly initialization (AI) approach reduces the drift by adding an estimate of the bias onto the observations at the expense of a larger initial error. In this study FFI is associated with the fidelity paradigm, and AI is associated with an instance of the mapping paradigm, in which the initial conditions are mapped onto the imperfect model attractor by adding a fixed error term; the mapped state on the model attractor should correspond to the nature state. Two diagnosis tools assess how well AI conforms to its own paradigm under various circumstances of model error: the degree of approximation of the model attractor is measured by calculating the overlap of the AI initial conditions PDF with the model PDF; and the sensitivity to random error in the initial conditions reveals how well the selected initial conditions on the model attractor correspond to the nature states. As a useful reference, the initial conditions of FFI are subjected to the same analysis. Conducting hindcast experiments using a hierarchy of low-order coupled climate models, it is shown that the initial conditions generated using AI approximate the model attractor only under certain conditions: differences in higher-than-first-order moments between the model and nature PDFs must be negligible. Where such conditions fail, FFI is likely to perform better

Resistive switching in Al/Tb/SiO2 nano-multilayers

Màster en Nanociència i Nanotecnologia, Facultat de Física, Universitat de Barcelona, Curs: 2016-2017. Tutors: Blas Garrido Fernández , Oriol Blázquez GómezResistive switching mechanism in memristors offers wide novel properties for nanoelectronics devices. In this work, we report an Al/Tb/SiO2 nano-multilayer memristor. Our devices were fabricated in terms of electron beam evaporation with thicknesses in the order of nanometres. Our devices exhibit memristive behaviour with a high change in resistance which can be cycled up to 20 times at room temperature. The states can persist at least for 140 h. We report bipolar switching with set and reset voltages with a low dispersion during the cycling. We have also studied the impact of the compliance current. Additionally, we studied which conduction mechanism is carrying out the memristive behaviour of our samples, where an Ohmic conduction in the low resistance state is observed and a Schottky fit is applied at the high resistance state. Current-time characteristics of the devices is also shown, where fluctuations and the time of commutation are presented. Finally, we also report the structural characterization of another type of samples, where only the switching mechanism is the aim of study. We have supposed that valence change mechanism is the responsible for the switching mechanis

Cerca de 300 meteoritos "impactan" en el MNCN

Se habla de la exposición permanente de meteoritos en el Museo Nacional de Ciencias Naturales (Madrid).Peer reviewe

Familial Traces: Photography and Trauma in Doris Lessing’s Auto/biographical Narratives

This paper deals with the use of photography in Doris Lessing’s auto/biographical writings, particularly, Under My Skin: Volume One of My Autobiography, to 1949 (1994), and more recently, Alfred and Emily (2008). Both works deal with Lessing’s personal and collective trauma: her strained relationship with her mother, and her struggle for recognition, as well as the pernicious influence the Great War had upon Lessing’s parents, and by extension, upon Lessing herself. Trauma studies, as seen in the winter-spring 2008 special double issue of Doris Lessing Studies entirely devoted to trauma in Lessing’s work, have provided nuanced readings into Lessing’s take on trauma in her production. Although the (im)possibility of recovery from trauma has become a recent focus of interest in Lessing studies, as in the double issue, there has been no specific reference to the relevance of photography and/in trauma. The aim of this paper is to examine personal photographs as relevant cultural documents in Lessing’s auto/biographical texts, and her engagement with personal and collective trauma, by paying attention to a neglected aspect: the use of family photography.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech