Metal-Insulator-Transition in a Weakly interacting Disordered Electron System

The interplay of interactions and disorder is studied using the Anderson-Hubbard model within the typical medium dynamical cluster approximation. Treating the interacting, non-local cluster self-energy ($\Sigma_c[{\cal \tilde{G}}](i,j\neq i)$) up to second order in the perturbation expansion of interactions, $U^2$, with a systematic incorporation of non-local spatial correlations and diagonal disorder, we explore the initial effects of electron interactions ($U$) in three dimensions. We find that the critical disorder strength ($W_c^U$), required to localize all states, increases with increasing $U$; implying that the metallic phase is stabilized by interactions. Using our results, we predict a soft pseudogap at the intermediate $W$ close to $W_c^U$ and demonstrate that the mobility edge ($\omega_\epsilon$) is preserved as long as the chemical potential, $\mu$, is at or beyond the mobility edge energy.Comment: 10 Pages, 8 Figures with Supplementary materials include

La mortalidad por cáncer en las comarcas de cataluña (1983–1989)

ResumenObjectivosComparar la mortalidad intercomarcal de Cataluña para algunos de los tumores malignos más frecuentes.MetodologíaSe han analizado los datos globales y de cinco localizaciones tumorales específicas relativos a la mortalidad por cáncer de un período de siete años (1983-1989). Se han obtenido las tasas brutas de mortalidad y las específicas para cada localización analizada. La comparación intercomarcal se ha realizado ajustando las tasas por edad mediante el método directo, tomando como referencia la población de Cataluña de 1986. Se han calculado las razones comparativas de mortalidad (RCM) de cada comarca respecto a Cataluña.ResultadosLa mortalidad global por cáncer es más alta en la comarca del Barcelonés para los hombres y en la de Osona para las mujeres. La RCM de los hombres del Barcelonés es la más alta para el cáncer de tráquea, bronquios y pulmón; la de la comarca del Solsonés es la más alta para el cáncer de estómago, y la de la Cerdanya es la más alta para el cáncer de colon y recto. Entre las mujeres, la RCM más alta para el cáncer de tráquea, bronquios y pulmón la presenta la comarca del Montsiá, para el cáncer de mama la del Baix Empordá y para el cáncer de estómago la del Alt Urgell.ConclusionesEl análisis comparativo de la mortalidad por cáncer, por comarcas y por sexos, permite observar importantes diferencias en la manifestación del fenómeno, lo cual puede orientar de manera más específica las políticas de control del cáncer y de investigación a desarrollar en cada territorio.SummaryObjectivesTo compare mortality among counties (comarques) in Catalonia, Spain for the most frequent malignant tumors.MethodsOverall mortality data and for five specific tumor sites were analyzed for a five-year period (1983-1989). Crude and site-specific mortality rates were computed. The comparison between counties was adjusted for the 1986 population of Catalonia using the direct method. Comparative mortality ratios (CMR) were obtained for each county with respect to Catalonia.ResultsOverall cancer mortality was higher in the Barcelonés for men and in Osona form women. The CMR for men in the Barcelonés was the highest for cancer of the trachea, bronchi and lungs; the CMR in Solsonés was the highest for stomach cancer, while in Cerdanya it was the highest for colorectal cancer. Among women, the highest CMR for cancer of the trachea, bronchi and lungs was in Montsiá, whereas for breast cancer it was Baix Empordá, and Alt Urgell for stomach cancer.ConclusionsComparative analyses of cancer mortality by county in Catalonia and sex underscores differences in its distribution, allowing the orientation of cancer control policies and research to be developed in each geographical area

Complexes of Pd(II) and Pt(II) with 9-Aminoacridine: Reactions with DNA and Study of Their Antiproliferative Activity

Four new metal complexes {M = Pd(II) or Pt(II)} containing the ligand 9-aminoacridine (9AA) were prepared. The compounds were characterized by FT-IR and 1H, 13C, and 195Pt NMR spectroscopies. Crystal structure of the palladium complex of formulae [Pd(9AA)(μ-Cl)]2 · 2DMF was determined by X-ray diffraction. Two 9-acridine molecules in the imine form bind symmetrically to the metal ions in a bidentate fashion through the imine nitrogen atom and the C(1) atom of the aminoacridine closing a new five-membered ring. By reaction with phosphine or pyridine, the Cl bridges broke and compounds with general formulae [Pd(9AA)Cl(L)] (where L = PPh3 or py) were formed. A mononuclear complex of platinum of formulae [Pt(9AA)Cl(DMSO)] was also obtained by direct reaction of 9-aminoacridine and the complex [PtCl2(DMSO2]. The capacity of the compounds to modify the secondary and tertiary structures of DNA was evaluated by means of circular dichroism and electrophoretic mobility. Both palladium and platinum compounds proved active in the modification of both the secondary and tertiary DNA structures. AFM images showed noticeable modifications of the morphology of the plasmid pBR322 DNA by the compounds probably due to the intercalation of the complexes between base pairs of the DNA molecule. Finally, the palladium complex was tested for antiproliferative activity against three different human tumor cell lines. The results suggest that the palladium complex of formula [Pd(9AA)(μ-Cl)]2 has significant antiproliferative activity, although it is less active than cisplatin

Meat consumption and consumer attitudes in México: Can persistence lead to change?

Meat is an essential element of contemporary Mexican culture. Its consumption is linked to ancestral elements as well as to agri-food globalization. Currently, the three types of meat most consumed by Mexicans are chicken (35 kg/person/year), pork (20 kg/person/year) and beef (15 kg/person/year). The consumption of these types of meats is highly influenced by price, regional preferences and emerging trends related to health, environmental and animal welfare concerns. The Mexican diet also includes other types of meats such as turkey, horse, sheep, goat and rabbit; their consumption is related to factors associated with health, tradition and availability. Mexico is the Latin American country with the highest number of people who follow plant-based diets, with 19% being vegetarian, 15% flexitarian and 9% vegan. This overview shows that the persistence of meat consumption in the country is not a uniform phenomenon, where deep-rooted culinary traditions coexist with changes in the horizon influenced by globalization, health and environmental concerns, animal welfare and household income

Enhancing Transport Efficiency by Hybrid Routing Strategy

Traffic is essential for many dynamic processes on real networks, such as internet and urban traffic systems. The transport efficiency of the traffic system can be improved by taking full advantage of the resources in the system. In this paper, we propose a dual-strategy routing model for network traffic system, to realize the plenary utility of the whole network. The packets are delivered according to different "efficient routing strategies" [Yan, et al, Phys. Rev. E 73, 046108 (2006)]. We introduce the accumulate rate of packets, {\eta} to measure the performance of traffic system in the congested phase, and propose the so-called equivalent generation rate of packet to analyze the jamming processes. From analytical and numerical results, we find that, for suitable selection of strategies, the dual- strategy system performs better than the single-strategy system in a broad region of strategy mixing ratio. The analytical solution to the jamming processes is verified by estimating the number of jammed nodes, which coincides well with the result from simulation.Comment: 6 pages, 3 figure

Analysis of cybersecurity threats in Industry 4.0: the case of intrusion detection

Nowadays, industrial control systems are experiencing a new revolution with the interconnection of the operational equipment with the Internet, and the introduction of cutting-edge technologies such as Cloud Computing or Big data within the organization. These and other technologies are paving the way to the Industry 4.0. However, the advent of these technologies, and the innovative services that are enabled by them, will also bring novel threats whose impact needs to be understood. As a result, this paper provides an analysis of the evolution of these cyber-security issues and the requirements that must be satis ed by intrusion detection defense mechanisms in this context.Springer ; Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

Role of the van Hove Singularity in the Quantum Criticality of the Hubbard Model

A quantum critical point (QCP), separating the non-Fermi liquid region from the Fermi liquid, exists in the phase diagram of the 2D Hubbard model [Vidhyadhiraja et. al, Phys. Rev. Lett. 102, 206407 (2009)]. Due to the vanishing of the critical temperature associated with a phase separation transition, the QCP is characterized by a vanishing quasiparticle weight. Near the QCP, the pairing is enhanced since the real part of the bare d-wave p-p susceptibility exhibits algebraic divergence with decreasing temperature, replacing the logarithmic divergence found in a Fermi liquid [Yang et. al, Phys. Rev. Lett. 106, 047004 (2011)]. In this paper we explore the single-particle and transport properties near the QCP. We focus mainly on a van Hove singularity (vHS) coming from the relatively flat dispersion that crosses the Fermi level near the quantum critical filling. The flat part of the dispersion orthogonal to the antinodal direction remains pinned near the Fermi level for a range of doping that increases when we include a negative next-near-neighbor hopping t' in the model. For comparison, we calculate the bare d-wave pairing susceptibility for non-interacting models with the usual two-dimensional tight binding dispersion and a hypothetical quartic dispersion. We find that neither model yields a vHS that completely describes the critical algebraic behavior of the bare d-wave pairing susceptibility. The resistivity, thermal conductivity, thermopower, and the Wiedemann-Franz Law are examined in the Fermi liquid, marginal Fermi liquid, and pseudo-gap doping regions. A negative next-near-neighbor hopping t' increases the doping region with marginal Fermi liquid character. Both T and negative t' are relevant variables for the QCP, and both the transport and the motion of the vHS with filling suggest that they are qualitatively similar in their effect.Comment: 15 pages, 17 figure

An explicit formula for the Berezin star product

We prove an explicit formula of the Berezin star product on Kaehler manifolds. The formula is expressed as a summation over certain strongly connected digraphs. The proof relies on a combinatorial interpretation of Englis' work on the asymptotic expansion of the Laplace integral.Comment: 19 pages, to appear in Lett. Math. Phy

Resource boxing: Converting realistic cloud task utilization patterns for theoretical scheduling

Scheduling is a core component within distributed systems to determine optimal allocation of tasks within servers. This is challenging within modern Cloud computing systems - comprising millions of tasks executing in thousands of heterogeneous servers. Theoretical scheduling is capable of providing complete and sophisticated algorithms towards a single objective function. However, Cloud computing systems pursue multiple and oftentimes conflicting objectives towards provisioning high levels of performance, availability, reliability and energy-efficiency. As a result, theoretical scheduling for Cloud computing is performed by simplifying assumptions for applicability. This is especially true for task utilization patterns, which fluctuate in practice yet are modelled as piecewise constant in theoretical scheduling models. While there exists work for modelling dynamic Cloud task patterns for evaluating applied scheduling, such models are incompatible with the inputs needed for theoretical scheduling - which require such patterns to be represented as boxes. Presently there exist no methods capable of accurately converting real task patterns derived from empirical data into boxes. This results in a significant gap towards theoreticians understanding and proposing algorithms derived from realistic assumptions towards enhanced Cloud scheduling. This work proposes resource boxing - an approach for automated conversion of realistic task patterns in Cloud computing directly into box-inputs for theoretical scheduling. We propose four resource conversion algorithms capable of accurately representing real task utilization patterns in the form of scheduling boxes. Algorithms were evaluated using production Cloud trace data, demonstrating a difference between real utilization and scheduling boxes less than 5%. We also provide an application for how resource boxing can be exploited to directly translate research from the applied community into the theoretical community

Toeplitz operators on symplectic manifolds

We study the Berezin-Toeplitz quantization on symplectic manifolds making use of the full off-diagonal asymptotic expansion of the Bergman kernel. We give also a characterization of Toeplitz operators in terms of their asymptotic expansion. The semi-classical limit properties of the Berezin-Toeplitz quantization for non-compact manifolds and orbifolds are also established.Comment: 40 page