Multifractality in spin glasses.

We unveil the multifractal behavior of Ising spin glasses in their low-temperature phase. Using the Janus II custom-built supercomputer, the spin-glass correlation function is studied locally. Dramatic fluctuations are found when pairs of sites at the same distance are compared. The scaling of these fluctuations, as the spin-glass coherence length grows with time, is characterized through the computation of the singularity spectrum and its corresponding Legendre transform. A comparatively small number of site pairs controls the average correlation that governs the response to a magnetic field. We explain how this scenario of dramatic fluctuations (at length scales smaller than the coherence length) can be reconciled with the smooth, self-averaging behavior that has long been considered to describe spin-glass dynamics.

L2C2: Last-level compressed-contents non-volatile cache and a procedure to forecast performance and lifetime.

Several emerging non-volatile (NV) memory technologies are rising as interesting alternatives to build the Last-Level Cache (LLC). Their advantages, compared to SRAM memory, are higher density and lower static power, but write operations wear out the bitcells to the point of eventually losing their storage capacity. In this context, this paper presents a novel LLC organization designed to extend the lifetime of the NV data array and a procedure to forecast in detail the capacity and performance of such an NV-LLC over its lifetime. From a methodological point of view, although different approaches are used in the literature to analyze the degradation of an NV-LLC, none of them allows to study in detail its temporal evolution. In this sense, this work proposes a forecasting procedure that combines detailed simulation and prediction, allowing an accurate analysis of the impact of different cache control policies and mechanisms (replacement, wear-leveling, compression, etc.) on the temporal evolution of the indices of interest, such as the effective capacity of the NV-LLC or the system IPC. We also introduce L2C2, a LLC design intended for implementation in NV memory technology that combines fault tolerance, compression, and internal write wear leveling for the first time. Compression is not used to store more blocks and increase the hit rate, but to reduce the write rate and increase the lifetime during which the cache supports near-peak performance. In addition, to support byte loss without performance drop, L2C2 inherently allows N redundant bytes to be added to each cache entry. Thus, L2C2+N, the endurance-scaled version of L2C2, allows balancing the cost of redundant capacity with the benefit of longer lifetime. For instance, as a use case, we have implemented the L2C2 cache with STT-RAM technology. It has affordable hardware overheads compared to that of a baseline NV-LLC without compression in terms of area, latency and energy consumption, and increases up to 6-37 times the time in which 50% of the effective capacity is degraded, depending on the variability in the manufacturing process. Compared to L2C2, L2C2+6 which adds 6 bytes of redundant capacity per entry, that means 9.1% of storage overhead, can increase up to 1.4-4.3 times the time in which the system gets its initial peak performance degraded.

An Amplifier-Less Acquisition Chain for Power Measurements in Series Resonant Inverters.

Successive approximation register (SAR) analog-to-digital converter (ADC) manufacturers recommend the use of a driver amplifier to achieve the best performance. When a driver amplifier is not used, the conversion speed is severely penalized because of the need to meet the settling time constraint. This paper proposes a simple digital correction method to raise the performance (conversion speed and/or accuracy) when the acquisition chain lacks a driver amplifier. It is intended to reduce the cost, size and power consumption of the conditioning circuit while maintaining acceptable performance. The method is applied to the measurement of the output power delivered by a series resonant inverter for domestic induction heating.

The Mpemba effect in spin glasses is a persistent memory effect.

The Mpemba effect occurs when a hot system cools faster than an initially colder one, when both are refrigerated in the same thermal reservoir. Using the custom-built supercomputer Janus II, we study the Mpemba effect in spin glasses and show that it is a nonequilibrium process, governed by the coherence length ξ of the system. The effect occurs when the bath temperature lies in the glassy phase, but it is not necessary for the thermal protocol to cross the critical temperature. In fact, the Mpemba effect follows from a strong relationship between the internal energy and ξ that turns out to be a sure-tell sign of being in the glassy phase. Thus, the Mpemba effect presents itself as an intriguing avenue for the experimental study of the coherence length in supercooled liquids and other glass formers.

A statics-dynamics equivalence through the fluctuation-dissipation ratio provides a window into the spin-glass phase from nonequilibrium measurements.

We have performed a very accurate computation of the nonequilibrium fluctuation-dissipation ratio for the 3D Edwards-Anderson Ising spin glass, by means of large-scale simulations on the special-purpose computers Janus and Janus II. This ratio (computed for finite times on very large, effectively infinite, systems) is compared with the equilibrium probability distribution of the spin overlap for finite sizes. Our main result is a quantitative statics-dynamics dictionary, which could allow the experimental exploration of important features of the spin-glass phase without requiring uncontrollable extrapolations to infinite times or system sizes.

Thermodynamic glass transition in a spin glass without time-reversal symmetry.

Spin glasses are a longstanding model for the sluggish dynamics that appear at the glass transition. However, spin glasses differ from structural glasses in a crucial feature: they enjoy a time reversal symmetry. This symmetry can be broken by applying an external magnetic field, but embarrassingly little is known about the critical behavior of a spin glass in a field. In this context, the space dimension is crucial. Simulations are easier to interpret in a large number of dimensions, but one must work below the upper critical dimension (i.e., in d < 6) in order for results to have relevance for experiments. Here we show conclusive evidence for the presence of a phase transition in a four-dimensional spin glass in a field. Two ingredients were crucial for this achievement: massive numerical simulations were carried out on the Janus special-purpose computer, and a new and powerful finite-size scaling method.

Funcionalidad familiar en gestantes adolescentes - Instituto Nacional Materno Perinatal - 2011 / Family functionality in adolescents pregnant - National Institute Materno Perinatal - 2011

OBJETIVO: Determinar el grado de funcionalidad familiar existente en gestantes adolescentes que acudieron al Instituto Nacional Materno Perinatal de Lima-Perú en el periodo de Noviembre-Diciembre del 2011 mediante la aplicación del Test Apgar familiar modificado. MATERIAL Y METODOS: Estudio descriptivo en el que participaron 130 gestantes adolescentes, entre 12 y 17 años, que se atendieron en los servicios de hospitalización, psicoprofilaxis, estimulación prenatal y consultorios externos del Instituto Nacional Materno Perinatal 2011. La información fue recolectada a través de un formulario tipo encuesta. El análisis de datos se hizo mediante el uso del paquete estadístico de Excel y SPSS. RESULTADOS: La mayoría de las gestantes adolescentes tienen una familia de tipo disfuncional (90 por ciento). Respecto al área de adaptación 75 por ciento presentaban disfuncionalidad familiar; de las cuales el 37 por ciento era de grado leve, en el área de participación el 81 por ciento poseen disfuncionalidad familiar, de las cuales el 36 por ciento fue leve. Sobre el área de crecimiento el 69 por ciento poseía disfuncionalidad familiar, de las cuales el 43 por ciento fue leve. Respecto al área de afecto el 87 por ciento presentaban disfuncionalidad familiar; dentro de las cuales el 32 por ciento fue leve, y otro 32 por ciento moderada. Finalmente en el área de recursos el 85 por ciento presentaron disfuncionalidad familiar, de las cuales el 34 por ciento fue moderado. CONCLUSIÓN: El funcionamiento familiar, según la calificación del test del Apgar familiar modificado, de la mayoría de las adolescentes embarazadas es disfuncional, el cual se encuentra presente en las cinco áreas, de las cuales el grado de disfuncionalidad que presentaron con mayor frecuencia fue el de disfunción familiar leve

OBJETIVE: To determine the degree of family functionality exists in pregnant adolescents who attended the Maternal Perinatal Institute in Lima, Peru in November-December period of 2011 by applying the modified family Apgar test. MATERIAL AND METHODS: A descriptive study involving 130 pregnant teenage women between 12 and 17 who are treated in inpatient services, psycho, and outpatient prenatal stimulation of the Maternal Perinatal Institute. Data were collected through a survey type form. Data analysis was done using the statistical package of Excel and SPSS. RESULTS: Most pregnant teenagers have a dysfunctional family of type (90 per cent). Regarding the area of adaptation 75 per cent had dysfunctional families, of which 37 per cent were mild in the area of participation, 81 per cent have dysfunctional families, of which 36 per cent was mild. On the growth area, 69 per cent had dysfunctional families, of which 43 per cent was mild. Regarding the area affected 87 per cent of respondents had dysfunctional families, within which 32 per cent was mild, moderate and another 32 per cent. Finally in the resource area, 85 per cent had dysfunctional families, of which 34 per cent was moderate. CONCLUSION: Family functioning, as defined by the family Apgar test modified the majority of pregnant adolescents is dysfunctional, which is present in all five areas, of which the degree of dysfunction that occurred most frequently was the mild family dysfunction