Monte Carlo analysis of critical phenomenon of the Ising model on memory stabilizer structures

We calculate the critical temperature of the Ising model on a set of graphs representing a concatenated three-bit error-correction code. The graphs are derived from the stabilizer formalism used in quantum error correction. The stabilizer for a subspace is defined as the group of Pauli operators whose eigenvalues are +1 on the subspace. The group can be generated by a subset of operators in the stabilizer, and the choice of generators determines the structure of the graph. The Wolff algorithm, together with the histogram method and finite-size scaling, is used to calculate both the critical temperature and the critical exponents of each structure. The simulations show that the choice of stabilizer generators, both the number and the geometry, has a large effect on the critical temperature.Comment: 7 pages, 6 figures, 5 table

Analytical solution of thermal magnetization on memory stabilizer structures

We return to the question of how the choice of stabilizer generators affects the preservation of information on structures whose degenerate ground state encodes a classical redundancy code. Controlled-not gates are used to transform the stabilizer Hamiltonian into a Hamiltonian consisting of uncoupled single spins and/or pairs of spins. This transformation allows us to obtain an analytical partition function and derive closed form equations for the relative magnetization and susceptibility. These equations are in agreement with the numerical results presented in [arXiv:0907.0394v1] for finite size systems. Analytical solutions show that there is no finite critical temperature, Tc=0, for all of the memory structures in the thermodynamic limit. This is in contrast to the previously predicted finite critical temperatures based on extrapolation. The mismatch is a result of the infinite system being a poor approximation even for astronomically large finite size systems, where spontaneous magnetization still arises below an apparent finite critical temperature. We extend our analysis to the canonical stabilizer Hamiltonian. Interestingly, Hamiltonians with two-body interactions have a higher apparent critical temperature than the many-body Hamiltonian.Comment: 13 pages, 7 figures, analytical solutions of problems studied numerically in arXiv:0907.0394v1 [quant-ph

Liquid rocket engine axial-flow turbopumps

The axial pump is considered in terms of the total turbopump assembly. Stage hydrodynamic design, pump rotor assembly, pump materials for liquid hydrogen applications, and safety factors as utilized in state of the art pumps are among the topics discussed. Axial pump applications are included

Paresia poscrítica durante estudios de monitorización de vídeo-EEG

To know the frequency of Todd s paralysis during the video EEG monitoring studies, to investigate in its pathophysiology, and to confirm its value to localise the epileptic focus. PATIENTS AND METHODS: We reviewed 114 monitoring studies, in 102 patients. RESULTS: Sixty patients had epileptic seizures. An obvious paresis was noted in four seizures of two patients (3 and 1, respectively). Both patients had frontal epilepsy. During the paralysis, in the first patient the EEG showed ictal discharges on the contralateral centrotemporal area. In the second patient, the EEG demonstrated slow waves in the contralateral frontal region. The ictal onset was contralateral to the paresis in all cases. No patient with pseudoseizures had paralysis. CONCLUSIONS: Postconvulsive paralysis are not frequent in video EEG monitoring studies. However, if present it points out to a contralateral seizure onset. In our series it happened in patients with frontal seizures. The EEG may help to clarify if it correspond to a true postictal phenomenon or to a ictal paralysis

The training of investigative skills and their Trends in Educational Leadership. Methodological Proposal

Las dinámicas contemporáneas de la Universidad, condicionan investigaciones sobre los procesos de formación profesional con especial énfasis en la formación de las competencias investigativas en docentes y su empoderamiento como líderes científicos. A estos empeños los académicos e investigadores, prestan sus mejores esfuerzos, tratando de potenciar una universidad pertinente, capaz de empoderar a sus profesionales de la plenitud humana liberadora que requiere la sociedad del siglo XXI. La investigación que se presenta responde a la pregunta ¿Cómo contribuir a la formación de líderes científicos en las universidades? Situando su objetivo en desarrollar los procesos de gestión formativa permanente de profesores investigadores, para así convertirlos en agentes de transformación de los contextos laborales en sus l territorios. A través de métodos y teorías científicas se revela la trascendencia de los procesos formativos de investigadores docentes y su valor para la potenciación de los procesos científicos en la comunidad universitaria. Desarrollándose una metodología de intervención para la Universidad UNIANDES, que propicia el surgimiento de líderes investigativosThe contemporary dynamics of the University, condition research on the processes of professional training with special emphasis on the training of research competencies in teachers and their empowerment as scientific leaders. To these efforts academics and researchers, they give their best efforts, trying to promote a relevant university, capable of empowering their professionals to the liberating human fullness that society of the 21st century requires. The research that is presented responds to the question How to contribute to the formation of scientific leaders in the universities? Setting its objective in developing the processes of permanent formative management of research professors, so as to transform them into agents of transformation of labor contexts in their territories. Through scientific methods and theories the transcendence of the educational processes of educational researchers and their value for the enhancement of the scientific processes in the university community is revealed. Developing an intervention methodology for UNIANDES University, which promotes the emergence of investigative leader

Aniline incorporated silica nanobubbles

We report the synthesis of stearate functionalized nanobubbles of SiO2 with a few aniline molecules inside, represented as C6H5NH2@SiO2@stearate, exhibiting fluorescence with red-shifted emission. Stearic acid functionalization allows the materials to be handled just as free molecules, for dissolution, precipitation, storage etc. The methodology adopted involves adsorption of aniline on the surface of gold nanoparticles with subsequent growth of a silica shell through monolayers, followed by the selective removal of the metal core either using sodium cyanide or by a new reaction involving halocarbons. The material is stable and can be stored for extended periods without loss of fluorescence. Spectroscopic and voltammetric properties of the system were studied in order to understand the interaction of aniline with the shell as well as the monolayer, whilst transmission electron microscopy has been used to study the silica shell

An asymptotic evaluation of the Green's functions for a planar single-layered microstrip antenna

Maxwell's equations and the boundary conditions for an arbitrarily polarized infinitesimal horizontal electric dipole over a dielectric slab ground plane can be used to obtain the asymptotic solution of the vector potential Green's functions. The dielectric material is linear, isotropic, homogeneous, and has a relative permittivity of e, and permeability ? 0. The ground plane is an infinite perfect electric conductor. The Green's functions are used to obtain the radiated fields generated by microstrip antenna surface current distributions. A comparison between the asymptotic methods of steepest descents and stationary phase shows that the spherical wave for both methods is mathematically the same. The cylindrical or surface wave is obtained here by the method of steepest descents. To obtain the cylindrical wave through the method of stationary phase additional steps are required which adds complexity to the solution. Both the cylindrical and spherical waves are evaluated for the effect of the dielectric on their respective radiated fields. The microstrip antenna patterns were also evaluated for some ideal current distributions. For the microstrip, as the dielectric constant e, increases the field pattern broadens and as the dielectric thickness d increases the field pattern narrows.California State University, Northridge. Department of Engineering.Includes bibliographical references (pages 113-116

Predicting risk for Alcohol Use Disorder using longitudinal data with multimodal biomarkers and family history: a machine learning study.

Predictive models have succeeded in distinguishing between individuals with Alcohol use Disorder (AUD) and controls. However, predictive models identifying who is prone to develop AUD and the biomarkers indicating a predisposition to AUD are still unclear. Our sample (n = 656) included offspring and non-offspring of European American (EA) and African American (AA) ancestry from the Collaborative Study of the Genetics of Alcoholism (COGA) who were recruited as early as age 12 and were unaffected at first assessment and reassessed years later as AUD (DSM-5) (n = 328) or unaffected (n = 328). Machine learning analysis was performed for 220 EEG measures, 149 alcohol-related single nucleotide polymorphisms (SNPs) from a recent large Genome-wide Association Study (GWAS) of alcohol use/misuse and two family history (mother DSM-5 AUD and father DSM-5 AUD) features using supervised, Linear Support Vector Machine (SVM) classifier to test which features assessed before developing AUD predict those who go on to develop AUD. Age, gender, and ancestry stratified analyses were performed. Results indicate significant and higher accuracy rates for the AA compared with the EA prediction models and a higher model accuracy trend among females compared with males for both ancestries. Combined EEG and SNP features model outperformed models based on only EEG features or only SNP features for both EA and AA samples. This multidimensional superiority was confirmed in a follow-up analysis in the AA age groups (12-15, 16-19, 20-30) and EA age group (16-19). In both ancestry samples, the youngest age group achieved higher accuracy score than the two other older age groups. Maternal AUD increased the model's accuracy in both ancestries' samples. Several discriminative EEG measures and SNPs features were identified, including lower posterior gamma, higher slow wave connectivity (delta, theta, alpha), higher frontal gamma ratio, higher beta correlation in the parietal area, and 5 SNPs: rs4780836, rs2605140, rs11690265, rs692854, and rs13380649. Results highlight the significance of sampling uniformity followed by stratified (e.g., ancestry, gender, developmental period) analysis, and wider selection of features, to generate better prediction scores allowing a more accurate estimation of AUD development

A new species of Shrew-opossum (Paucituberculata: Caenolestidae) with a phylogeny of extant Caenolestids

Este artículo trata sobre las 4 especies conocidas de ratones marsupiales, Caenolestes (Paucituberculata: Caenolestidae), están restringidas a los hábitats asociados con los Andes del norte de América del Sur. Cinco especímenes de una nueva especie de Caenolestes fueron colectados en el Parque Nacional Sangay en la Cordillera Oriental de Ecuador. Una revisión de especímenes de museo reveló 6 especímenes adicionales de esta especie nueva, aquí descrita como Caenolestes sangay