Analytical model of non-Markovian decoherence in donor-based charge quantum bits

We develop an analytical model for describing the dynamics of a donor-based charge quantum bit (qubit). As a result, the quantum decoherence of the qubit is analytically obtained and shown to reveal non-Markovian features: The decoherence rate varies with time and even attains negative values, generating a non-exponential decay of the electronic coherence and a later recoherence. The resulting coherence time is inversely proportional to the temperature, thus leading to low decoherence below a material dependent characteristic temperature.Comment: 19 pages, 3 figure

Tailoring electronic and optical properties of TiO2: nanostructuring, doping and molecular-oxide interactions

Titanium dioxide is one of the most widely investigated oxides. This is due to its broad range of applications, from catalysis to photocatalysis to photovoltaics. Despite this large interest, many of its bulk properties have been sparsely investigated using either experimental techniques or ab initio theory. Further, some of TiO2's most important properties, such as its electronic band gap, the localized character of excitons, and the localized nature of states induced by oxygen vacancies, are still under debate. We present a unified description of the properties of rutile and anatase phases, obtained from ab initio state of the art methods, ranging from density functional theory (DFT) to many body perturbation theory (MBPT) derived techniques. In so doing, we show how advanced computational techniques can be used to quantitatively describe the structural, electronic, and optical properties of TiO2 nanostructures, an area of fundamental importance in applied research. Indeed, we address one of the main challenges to TiO2-photocatalysis, namely band gap narrowing, by showing how to combine nanostructural changes with doping. With this aim we compare TiO2's electronic properties for 0D clusters, 1D nanorods, 2D layers, and 3D bulks using different approximations within DFT and MBPT calculations. While quantum confinement effects lead to a widening of the energy gap, it has been shown that substitutional doping with boron or nitrogen gives rise to (meta-)stable structures and the introduction of dopant and mid-gap states which effectively reduce the band gap. Finally, we report how ab initio methods can be applied to understand the important role of TiO2 as electron-acceptor in dye-sensitized solar cells. This task is made more difficult by the hybrid organic-oxide structure of the involved systems.Comment: 32 pages, 8 figure

Computational Design of Chemical Nanosensors: Metal Doped Carbon Nanotubes

We use computational screening to systematically investigate the use of transition metal doped carbon nanotubes for chemical gas sensing. For a set of relevant target molecules (CO, NH3, H2S) and the main components of air (N2, O2, H2O), we calculate the binding energy and change in conductance upon adsorption on a metal atom occupying a vacancy of a (6,6) carbon nanotube. Based on these descriptors, we identify the most promising dopant candidates for detection of a given target molecule. From the fractional coverage of the metal sites in thermal equilibrium with air, we estimate the change in the nanotube resistance per doping site as a function of the target molecule concentration assuming charge transport in the diffusive regime. Our analysis points to Ni-doped nanotubes as candidates for CO sensors working under typical atmospheric conditions

Non-Performing Loans: Regulatory and Accounting Treatments of Assets

Asset quality is an essential part of sound banking. However, asset quality is difficult for banking regulators and investors to assess in the absence of a common, cross-border scheme to classify assets. Currently no standard is applied universally to classify loans, the most sizable asset on many banks’ balance sheets. As a corollary, no common definition of non-performing loans (NPLs) exists. This paper documents divergences in the definition of NPLs across countries, accounting regimes, firms and data sources. The paper’s originality is in attending to the legal, accounting, statistical, economic and strategic aspects of loan loss provisioning (LLP) and NPLs, topics that are multidisciplinary by nature but have not been dealt with in the literature in an integrated fashion before. Since the 2007 Great Financial Crisis (GFC), accounting bodies and prudential regulators are increasingly focused on early recognition of credit losses and enhanced disclosure. A common approach to NPL recognition might complement these initiatives

Web based system architecture for long pulse remote experimentation

Remote experimentation (RE) methods will be essential in next generation fusion devices. Requirements for long pulse RE will be: on-line data visualization, on-line data acquisition processes monitoring and on-line data acquisition systems interactions (start, stop or set-up modifications). Note that these methods are not oriented to real-time control of fusion plant devices. INDRA Sistemas S.A., CIEMAT (Centro de Investigaciones Energéticas Medioambientales y Tecnológicas) and UPM (Universidad Politécnica de Madrid) have designed a specific software architecture for these purposes. The architecture can be supported on the BeansNet platform, whose integration with an application server provides an adequate solution to the requirements. BeansNet is a JINI based framework developed by INDRA, which makes easy the implementation of a remote experimentation model based on a Service Oriented Architecture. The new software architecture has been designed on the basis of the experience acquired in the development of an upgrade of the TJ-II remote experimentation system

A first step to accelerating fingerprint matching based on deformable minutiae clustering

Fingerprint recognition is one of the most used biometric methods for authentication. The identification of a query fingerprint requires matching its minutiae against every minutiae of all the fingerprints of the database. The state-of-the-art matching algorithms are costly, from a computational point of view, and inefficient on large datasets. In this work, we include faster methods to accelerating DMC (the most accurate fingerprint matching algorithm based only on minutiae). In particular, we translate into C++ the functions of the algorithm which represent the most costly tasks of the code; we create a library with the new code and we link the library to the original C# code using a CLR Class Library project by means of a C++/CLI Wrapper. Our solution re-implements critical functions, e.g., the bit population count including a fast C++ PopCount library and the use of the squared Euclidean distance for calculating the minutiae neighborhood. The experimental results show a significant reduction of the execution time in the optimized functions of the matching algorithm. Finally, a novel approach to improve the matching algorithm, considering cache memory blocking and parallel data processing, is presented as future work.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

Quantization of Hall Resistance at the Metallic Interface between an Oxide Insulator and SrTiO3_{3}

The two-dimensional metal forming at the interface between an oxide insulator and SrTiO3 provides new opportunities for oxide electronics. However, the quantum Hall effect, one of the most fascinating effects of electrons confined in two dimensions, remains underexplored at these complex oxide heterointerfaces. Here, we report the experimental observation of quantized Hall resistance in a SrTiO3 heterointerface based on the modulation-doped amorphous-LaAlO$_{3}$/SrTiO$_{3}$ heterostructure, which exhibits both high electron mobility exceeding 10000 cm$^{2}$/Vs and low carrier density on the order of ~10$^{12}$ cm$^{-2}$. Along with unambiguous Shubnikov-de Haas oscillations, the spacing of the quantized Hall resistance suggests that the interface is comprised of a single quantum well with ten parallel conducting two-dimensional subbands. This provides new insight into the electronic structure of conducting oxide interfaces and represents an important step towards designing and understanding advanced oxide devices

Filogenia de aislamientos entomopatógenos de Isaria spp. (Ascomycota: Hypocreales) provenientes de Argentina y Brasil.

Los hongos entomopatógenos del genero Isaria (Ascomycota: Hypocreales) son agentes de control natural de insectos plaga. La clasificación de sus especies generalmente se realiza por descripción de las características morfológicas, sin embargo, debido al carácter pleomórfico de algunas especies, su identificación se torna difícil. Actualmente, existen técnicas moleculares que permiten estudiar la variabilidad genética y establecer relaciones filogenéticas entre aislamientos fúngicos, como por ejemplo el secuenciamiento de las regiones espaciadoras intergénicas (ITS1-5,8S-ITS2) y el factor de elongación 1 alfa (EF1-?). En este trabajo investigamos las relaciones filogenéticas de 20 aislamientos de Isaria provenientes de Argentina y Brasil, con 51 especies fúngicas de la familia Clavicipitaceae, Cordycipitaceae y Ophiocordycipitaceae. La metodología consistió en la amplificación y el secuenciamiento de un fragmento de 1100pb correspondiendo a EF1-? y de un fragmento de 600pb correspondiente a ITS1-5,8S-ITS2. Las secuencias nucleotídicas de EF1-? fueron alineadas con el programa Clustal X y las secuencias de ITS1-5,8S-ITS2 con el programa Mafft. Los análisis de máxima parsimonia fueron realizados con el programa TNT y los árboles filogenéticos editados con el programa Dendroscope. Los resultados indicaron que el genero Isaria es polifilético y que se encuentra ubicado taxonómicamente dentro de la Familia Cordycipitaceae. Los aislamientos de I. fumosorosea, I. farinosa e I. tenuipes formaron tres clados fuertemente soportados y cercanamente emparentados con las especies de Beauveria, Lecanicillium y Simplicillium. Asimismo, se establecieron relaciones filogenéticas entre los estados anamórficos Isaria, Beauveria y Lecanicillium con los estados teleomórficos Cordyceps y Torrubiella. Por lo tanto, se puede concluir que los genes nucleares (EF1-? y ITS1-5,8S-ITS2) son una excelente herramienta para confirmar la identificación de los aislamientos fúngicos y establecer relaciones filogenéticas entre especies de hongos entomopatógenos

Use of plastic scrap in asphalt mixtures added by dry method as a partial substitute for bitumen

In recent decades, the generation of plastic waste has increased substantially worldwide, with the result that more of such waste is introduced into the environment. Currently, most polymers (polyethylene terephthalate, polyethylene, polyvinyl chloride, and others) are recycled. However, some are rejected for recycling in the primary separation processes due to their physical condition, contamination, or size. These materials are called plastic scrap. In this research, the use of plastic scrap added by dry method was evaluated as a replacement for bitumen in asphalt mixtures. Two sizes of plastic scrap, coarse and fine, were considered. An AC16S semi-dense mixture was designed for this purpose, with a 10% reduction in binder, and 10% and 20% of plastic scrap binder was added in coarse and fine sizes. The results obtained in the Marshall stability and flow test showed reduced moisture damage, greater indirect tensile strength, higher air void content, and a 2% decrease in the conserved tensile strength ratio while the same usage field as the conventional mixture was maintained. Meanwhile, significant decreases in plastic deformations, as compared to traditional values, were obtained from resilient modulus and rutting tests