Fitting and selecting scattering data

The main purpose of scattering experiments is to unveil the underlying structure of the colliding particles and their interaction. Typically one measures scattering observables (cross sections and polarizations) at discrete angles and energies and mutually consistent data may validate or falsify proposed theories or models. However, the accumulation of data from different laboratories while potentially improves the statistical significance it may sometimes generate mutually inconsistent data as a side-effect. Thus, some decision has to be made on what are the maximal amount of data which are mutually compatible. We show elastic $\pi N$ and $NN$ scattering as prominent examples where this selection is called for. We discuss how it can be done in a self-consistent manner invoking a principle of maximal consensus of the database and with the help of a sufficiently flexible model involving a minimal number of theoretical assumptions. In the NN case this has become possible with a combination of long distance field theoretical constraints at the hadronic level such as pion exchanges and electromagnetic effects and a coarse graining of the unknown interaction over the shortest de Broglie wavelength being probed in the scattering process.Comment: 7 pages, 5 figures, talk presented by ERA at XVII International Conference on Hadron Spectroscopy and Structure - Hadron2017, Salamanca, 25-29 September 201

Stochastic optimization methods for the simultaneous control of parameter-dependent systems

We address the application of stochastic optimization methods for the simultaneous control of parameter-dependent systems. In particular, we focus on the classical Stochastic Gradient Descent (SGD) approach of Robbins and Monro, and on the recently developed Continuous Stochastic Gradient (CSG) algorithm. We consider the problem of computing simultaneous controls through the minimization of a cost functional defined as the superposition of individual costs for each realization of the system. We compare the performances of these stochastic approaches, in terms of their computational complexity, with those of the more classical Gradient Descent (GD) and Conjugate Gradient (CG) algorithms, and we discuss the advantages and disadvantages of each methodology. In agreement with well-established results in the machine learning context, we show how the SGD and CSG algorithms can significantly reduce the computational burden when treating control problems depending on a large amount of parameters. This is corroborated by numerical experiments

Selective C(sp2)−H Halogenation of "click" 4-Aryl-1,2,3-triazoles

Selective bromination reactions of “click compounds” are described. Electron-neutral and electron-deficient arenes selectively undergo unprecedented Pd-catalyzed C–H ortho-halogenations assisted by simple triazoles as modular directing groups, whereas electron-rich arenes are regioselectively halogenated following an electrophilic aromatic substitution reaction pathway. These C–H halogenation procedures exhibit a wide group tolerance, complement existing bromination procedures, and represent versatile synthetic tools of utmost importance for the late-stage diversification of “click compounds”. The characterization of a triazole-containing palladacycle and density functional theory studies supported the mechanism proposal.We are grateful to Gobierno Vasco (ELKARTEK_KK-2015/0000101; IT_1033-16) and UPV/EHU (GIU15/31) for financial support. A. C. thanks MINECO for a Ramón y Cajal research contract (RYC-2012-09873). Cost-CHAOS action is also acknowledged

A new countermeasure against side-channel attacks based on hardware-software co-design

This paper aims at presenting a new countermeasure against Side-Channel Analysis (SCA) attacks, whose implementation is based on a hardware-software co-design. The hardware architecture consists of a microprocessor, which executes the algorithm using a false key, and a coprocessor that performs several operations that are necessary to retrieve the original text that was encrypted with the real key. The coprocessor hardly affects the power consumption of the device, so that any classical attack based on such power consumption would reveal a false key. Additionally, as the operations carried out by the coprocessor are performed in parallel with the microprocessor, the execution time devoted for encrypting a specific text is not affected by the proposed countermeasure. In order to verify the correctness of our proposal, the system was implemented on a Virtex 5 FPGA. Different SCA attacks were performed on several functions of AES algorithm. Experimental results show in all cases that the system is effectively protected by revealing a false encryption key.Peer ReviewedPreprin

800 años de la Carta Magna Inglesa: Su proyección en el derecho constitucional chileno

On June 15 of this year, the 800 years of the Magna Carta of John Lackland were celebrated. In its brief, but notable provisions, the first antecedents of Constitutional Law are condensed, in particular, of the fundamental freedoms of citizens and of the guarantees against abuses of power by the authority.El 15 de junio de este año se celebraron los 800 años de la Carta Magna de Juan Sin Tierra. En sus breves, pero notables disposiciones se condensan los primeros antecedentes del Derecho Constitucional, en particular, de las libertades fundamentales de los ciudadanos y de las garantías frente a los abusos del poder por parte de la autoridad

Hardware architecture implemented on FPGA for protecting cryptographic keys against side-channel attacks

This paper presents a new hardware architecture designed for protecting the key of cryptographic algorithms against attacks by side-channel analysis (SCA). Unlike previous approaches already published, the fortress of the proposed architecture is based on revealing a false key. Such a false key is obtained when the leakage information, related to either the power consumption or the electromagnetic radiation (EM) emitted by the hardware device, is analysed by means of a classical statistical method. In fact, the trace of power consumption (or the EM) does not reveal any significant sign of protection in its behaviour or shape. Experimental results were obtained by using a Virtex 5 FPGA, on which a 128-bit version of the standard AES encryption algorithm was implemented. The architecture could easily be extrapolated to an ASIC device based on standard cell libraries. The system is capable of concealing the real key when various attacks are performed on the AES algorithm, using two statistical methods which are based on correlation, the Welch’s t-test and the difference of means.Peer ReviewedPostprint (author's final draft

Donantes, reconstrucción y el futuro de Irak

El camino hasta la conferencia internacional de donantes celebrada en Madrid ha sido largo y su devenir ha corrido parejo al desarrollo de los acontecimientos políticos dentro y fuera de Irak, y especialmente en el marco del Consejo de Seguridad de Naciones Unidas. En las próximas semanas deberán ponerse en práctica un aluvión de iniciativas que han surgido en la Conferencia de Donantes, y si ha sido importante el número y la calidad de las mismas, deben destacarse los innumerables encuentros bilaterales que han tenido lugar entre empresarios y políticos de todos los países. Sin duda, hoy los ministros iraquíes, que destacan por su formación y su gran apertura de miras, son conocidos por la comunidad internacional, y éste es el primer gran paso hacia la estabilización del país. A su vez, conocemos mucho mejor cuales son las necesidades y las capacidades de la nación árabe y por tanto estamos en una óptima situación para avanzar en el proceso de reconocimiento internacional y en condiciones para un pleno reestablecimiento de las relaciones diplomáticas entre Irak y la comunidad internacional

El mercado de la defensa y la seguridad ante el reto de la transformación de los asuntos militares

Desde la caída del Muro de Berlín y el final de la Guerra Fría, los analistas geoestratégicos y las organizaciones militares han venido analizado las consecuencias que tendrían para la seguridad y la organización militar los cambios en el entorno estratégico

Constitutional basis of the taking reason and the dictaminate power of the General Comptroller of the Republic

El presente artículo indaga sobre el fundamento constitucional de la toma de razón de los actos administrativos y la emisión de dictámenes por parte de la Contraloría General de la República. Mientras la toma de razón importa un control preventivo de sujeción de los actos de la administración a la Constitución y a la ley, la potestad dictaminante es un acto de consulta formulado por órganos de la Administración del Estado o un acto de respuesta a peticiones de particulares o funcionarios. En ese sentido, al autor desarrolla el trasfondo normativo y los criterios jurisprudenciales que han configurado ambas facultades constitucionales, las tensiones suscitadas respecto a las facultades conservadoras de los tribunales de justicia, así como también las limitaciones que circunscriben el ejercicio de las potestades del órgano de control, objetos de este estudio.This article investigates the constitutional basis of the taking reason of administrative acts and the issuance of opinions concerning the General Comptroller of the Republic. While the taking reason imports a preventive control of subjection of the acts of the Administration to the Constitution and to the law, the dictaminate power its a consultation act formulated by the organs of the State administration or an act of response to requests from individuals or officials. In this sense, the author develops the normative background and the jurisprudence criteria that have shaped both constitutional powers, the tensions raised regarding the conservative powers of the courts of justice, as well the limitations that circumscribe the exercise of the powers of the control organ, objects of this study