Electrical tomography and TDEM prospection in the Chianciano thermal basin (Siena, Italy)

Chianciano thermal basin in Tuscany belongs to a great structure that extends, from San Casciano Bagni to Rapolano, orientated SSE-NNW. Several springs are located in this thermal field: Acqua Santa, Macerina, Casuccini and Sillene well. They are located close to the contact between the lower complex of the «Tuscan series» (Triassic limestones and dolomites) and Pliocene formations (sands and clayey sands, clays and silty clays). According to the groundwater flow scheme, the former formations represent the geothermal reservoir and, where they outcrop, the recharge areas. Thermalized fluids rise through direct faults, having an apennine orientation. In order to locate a new production well, electrical tomography and TDEM prospection were performed. Geophysical interpretation led to the construction of 1D imaged and 2D sections showing the main tectonic features. The different electrical behaviour of the hydrogeological units disclosed a fault located near the old Sillene well; this tectonic feature caused the uplifting of Triassic formations towards the north-east. A new production well was located close to the fault in the uplifted sector with excellent results as it captured the thermal aquifer at a depth of 30 m with a discharge up to 70 l/s

Dendritic flux penetration in Pb films with a periodic array of antidots

We explore the flux-jump regime in type-II Pb thin films with a periodic array of antidots by means of magneto-optical measurements. A direct visualization of the magnetic flux distribution allows to identify a rich morphology of flux penetration patterns. We determine the phase boundary $H^*(T)$ between dendritic penetration at low temperatures and a smooth flux invasion at high temperatures and fields. For the whole range of fields and temperatures studied, guided vortex motion along the principal axes of the square pinning array is clearly observed. In particular, the branching process of the dendrite expansion is fully governed by the underlying pinning topology. A comparative study between macroscopic techniques and direct local visualization shed light onto the puzzling $T-$ and $H-$independent magnetic response observed at low temperatures and fields. Finally, we find that the distribution of avalanche sizes at low temperatures can be described by a power law with exponent $\tau \sim 0.9(1)$

Spectral Relaxations and Fair Densest Subgraphs

Reducing hidden bias in the data and ensuring fairness in algorithmic data analysis has recently received significant attention. In this paper, we address the problem of identifying a densest subgraph, while ensuring that none of one binary protected attribute is disparately impacted. Unfortunately, the underlying algorithmic problem is NP-hard, even in its approximation version: approximating the densest fair subgraph with a polynomial-time algorithm is at least as hard as the densest subgraph problem of at most k vertices, for which no constant approximation algorithms are known. Despite such negative premises, we are able to provide approximation results in two important cases. In particular, we are able to prove that a suitable spectral embedding allows recovery of an almost optimal, fair, dense subgraph hidden in the input data, whenever one is present, a result that is further supported by experimental evidence. We also show a polynomial-time, $2$-approximation algorithm, whenever the underlying graph is itself fair. We finally prove that, under the small set expansion hypothesis, this result is tight for fair graphs. The above theoretical findings drive the design of heuristics, which we experimentally evaluate on a scenario based on real data, in which our aim is to strike a good balance between diversity and highly correlated items from Amazon co-purchasing graphs

Narrativas en la evaluación de prácticas y residencias

Este artículo examina la utilización de las narrativas en los procesos de formación de docentes; la cual se ha ido extendiendo y consolidando fundamentalmente en las últimas décadas. En tanto, como formadores de docentes, el uso deliberado de las narraciones radica en la potencialidad de las diversas herramientas de la narrativa que invitan a desarrollar procesos reflexivos por medio de la escritura, la lectura y el análisis. De esta manera, se vienen utilizando en distintos momentos o instancias de la formación, tanto en la enseñanza como en la evaluación y, en particular, en dispositivos de prácticas y residencias dado que resultan ser sumamente ricas para favorecer la reflexión acerca de esas prácticas

Type-1.5 Superconductors

We demonstrate the existence of a novel superconducting state in high quality two-component MgB2 single crystalline superconductors where a unique combination of both type-1 (kappa_1 0.707) superconductor conditions is realized for the two components of the order parameter. This condition leads to a vortex-vortex interaction attractive at long distances and repulsive at short distances, which stabilizes unconventional stripe- and gossamer-like vortex patterns that we have visualized in this type-1.5 superconductor using Bitter decoration and also reproduced in numerical simulations.Comment: accepted in Phys. Rev. Let

Direct visualization of magnetic vortex pinning in superconductors

We study the vortex structure in a Pb film deposited on top of a periodic array of ferromagnetic square microrings by combining two high resolution imaging techniques: Bitter decoration and scanning Hall probe microscopy (SHPM). The periodicity and strength of the magnetic pinning potential generated by the square microrings are controlled by the magnetic history of the template. When the square rings are in the magnetized dipolar state, known as the onion state, the strong stray field generated at the domain walls prevents the decoration of vortices. SHPM images show that the stray field generated by the dipoles is much stronger than the vortex field in agreement with the results of simulations. Real space vortex imaging has revealed that, in the onion state, the corners of the square rings act as effective pinning centers for vortices.Comment: To be published in Phys. Rev.

Training of teachers in the XXI century in Argentina: Consolidation of the trends of '90?

Las políticas para la formación de docentes de la década del 90 en la Argentina formaron parte del proyecto neoliberal que afectó a todas las áreas del Estado. Formuladas por el Consejo Federal de Cultura y Educación, apuntaron a reestructurar la formación y las instituciones formadoras de acuerdo con la Ley Federal de Educación. En línea con el discurso de la calidad educativa, se enfatizaron los procesos de evaluación y acreditación institucional, en los que el Proyecto Educativo Institucional (PEI) de cada institución pretendió ser la llave para la continuidad o no de las instituciones. También se instalaron mecanismos para la competencia entre las instituciones y la formación tuvo una impronta instrumental, tendiendo a formar un docente “aplicador” de estrategias para resolver los problemas de aprendizaje en el aula. A partir de 2006, con la creación del Instituto Nacional de Formación Docente (INFD) como órgano rector de las políticas que proponen superar la fragmentación heredada, las tendencias de los 90 se mantienen, profundizan o consolidan. Si bien se plantea una política que intenta articular el sistema formador (universitario y no universitario), sus líneas de trabajo no incluyen a las universidades. El INFD, por otra parte, ha avanzado en decisiones centralizadas que avanzan sobre las decisiones jurisdiccionales y su carácter puede inscribirse en los principios de la “nueva gestión pública”.En este trabajo intentamos analizar las políticas para la formación de docentes posteriores al cambio de gobierno en 2003, señalando las continuidades que resultan más evidentes y algunas incipientes posibilidades de rupturas.The policies used to form professors during the 90’s decade in Argentina were part of the neoliberal project that affected the State in all of its areas. Propossed by the Federal Council of Culture and Education, they pointed to reestructure the profesional trainning and forming institutions according to the Federal Law of Education. Jointly with education quality’s speech, evaluation and institutional accreditation processes were emphasized too, and the Institutional Proyect of Education (IPE) of each institution pretended to be the key to continuity or not of the institutions. Mechanisms for the competition among the institutions were settled as well, and professional training suddenly had an instrumental stamp, tending to make professors an “user” of strategies to solve learning’s problems inside the classroom. Since 2006, with the creation of the National Institute of Teaching Formation (NITF) -as leading organ of the policies that proppose to get over the inherited divisions- 90’s tendences remain, get deeper and solid. Altough a political line that tries to articulate the forming system (universitary and non-universitary) has been suggested, its horizon does not include universities. On the other hand, the NITF has advanced on its centralized decitions that move forward jurisdictional decitions and its character may be registred in the begginings of the “new public gestion”. In this work we try to analize professional trainning’s policies subsequent to the change of governement happened in 2003, remarking the more evident continuities and a few signes of possible breaks.Grupo de Investigación FORCE (Formación Centrada en la Escuela) Universidad de Granad

TIMP3 Is Reduced in Atherosclerotic Plaques From Subjects With Type 2 Diabetes and Increased by SirT1

Atherosclerosis is accelerated in subjects with type 2 diabetes by unknown mechanisms. We identified tissue inhibitor of metalloproteinase 3 (TIMP3), the endogenous inhibitor of A disintegrin and metalloprotease domain 17 (ADAM17) and other matrix metalloproteinases (MMPs), as a gene modifier for insulin resistance and vascular inflammation in mice. We tested its association with atherosclerosis in subjects with type 2 diabetes and identified Sirtuin 1 (SirT1) as a major regulator of TIMP3 expression

Electrical tomography and TDEM prospection in the Chianciano thermal basin (Siena, Italy)

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