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.

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.

Identification of risk features for complication in Gaucher's disease patients: a machine learning analysis of the Spanish registry of Gaucher disease.

BACKGROUND: Since enzyme replacement therapy for Gaucher disease (MIM#230800) has become available, both awareness of and the natural history of the disease have changed. However, there remain unmet needs such as the identification of patients at risk of developing bone crisis during therapy and late complications such as cancer or parkinsonism. The Spanish Gaucher Disease Registry has worked since 1993 to compile demographic, clinical, genetic, analytical, imaging and follow-up data from more than 400 patients. The aims of this study were to discover correlations between patients' characteristics at diagnosis and to identify risk features for the development of late complications; for this a machine learning approach involving correlation networks and decision trees analyses was applied. RESULTS: A total of 358 patients, 340 type 1 Gaucher disease and 18 type 3 cases were selected. 18% were splenectomyzed and 39% had advanced bone disease. 81% of cases carried heterozygous genotype. 47% of them were diagnosed before the year 2000. Mean age at diagnosis and therapy were 28 and 31.5 years old (y.o.) respectively. 4% developed monoclonal gammopathy undetermined significance or Parkinson Disease, 6% cancer, and 10% died before this study. Previous splenectomy correlates with the development of skeletal complications and severe bone disease (p = 0.005); serum levels of IgA, delayed age at start therapy (> 9.5 y.o. since diagnosis) also correlates with severe bone disease at diagnosis and with the incidence of bone crisis during therapy. High IgG (> 1750 mg/dL) levels and age over 60 y.o. at diagnosis were found to be related with the development of cancer. When modelling the decision tree, patients with a delayed diagnosis and therapy were the most severe and with higher risk of complications. CONCLUSIONS: Our work confirms previous observations, highlights the importance of early diagnosis and therapy and identifies new risk features such as high IgA and IgG levels for long-term complications.

Qualitative and quantitative evaluation of the use of Twitter as a tool of antimicrobial stewardship.

INTRODUCTION: Social media networks have transformed the sources of information, including health information. In particular, the microblogging service Twitter has been used as a learning tool in the field of medicine as well as a tool for disease surveillance and outbreak management. As antimicrobial resistance is one of the biggest concerns of public health, we aimed to review how Twitter is being used as a tool for antimicrobial stewardship (AMS). METHODS: We used the software Kampal Social® to collect, analyze and monitor tweets from the whole Twitter network to assess the activity that takes place about antibiotics. The study was carried out in three phases: data acquisition, during which we collected data over a six-month period (from 21 September 2016 to 8 February 2017) by monitoring selected users, hashtags and keywords that we knew to be related to AMS; data cleansing, which involved identifying users who were not related to the topic, thus creating a new collection process to remove those users and add newly discovered ones; and, finally, data acquisition and analysis (From 1 April 2017 to 7 March 2018), during which we collected data using the new users obtained in the cleansing phase. We qualitatively characterized the most influential users, we analysed the use of hashtags and the flow of information (the most retweeted users and the global network formed by all the users). RESULTS: Using the tool Kampal Social®, and after a cleansing phase to remove irrelevant information, we worked with a dataset of 1,765,388 tweets. Studying the qualitative characterization of the top-ten influencers, we found that most of them are institutional users, but individual users, such as physicians, and an important medical journal also appeared. Regarding hashtags, '#antibiotics' was the one with the most occurrences. Hashtags follow a regular distribution over time, with some defined peaks connected to important dates and reports about antibiotics. As for the flow of information, we obtained a rather dense network of interconnections formed by all the users who had sent a message, which means that a strong relation exists between the different organizations, professionals and users in general. CONCLUSIONS: Institutions, medical journals, physicians and pharmacists are key opinion leaders in the topic of antibiotics, so they must incorporate social media into their communication strategy to spread the AMS message. More evidence is needed regarding the optimal method of communication to spread information throughout the general population. The development of tools capable of collecting and querying large amounts of Twitter data helped us to assess the impact of antibiotic awareness campaigns and to gain an idea of how Twitter is being used to spread the message about AMS.

[Costs-analysis of methadone program in the autonomous community La Rioja, Spain]. / Análisis de costes del programa de metadona en la Comunidad Autónoma de La Rioja.

BACKGROUND: Methadone programs have been organized in each Spanish region in a specific way. In spite of the regional interests to manage those programs in a more efficient way, so far the costs of the programs are unknown. As a previous step, it would be desirable to understand the activities related to these programs as well as their respective costs. This article aims to calculate the cost of the Methadone program in the autonomous community of La Rioja, and to understand those parameters which generate a greater cost to this programme. METHODS: The study followed a similar structure as the research recently applied to the region of Murcia. The reference year for the study of the annual costs of the Methadone program was 2010. Data were obtained from different registries of several institutions involved in the regional program. Costs were classified according to different stages and dispensation centres which participated in this programme. RESULTS: Data analysis, for a concentration of 2 mg/ml of methadone, showed an approximate annual cost of 165.759 euros. Taking the total number of patients into consideration the individual cost was 412,34 euros. CONCLUSIONS: Dispensation is the stage which caused the largest cost to the programme, the highest per patient cost corresponded to the centre with less patients due to the fact that fixed costs are shared by a smaller group of persons; the biggest global cost of the programme came from Logroño's center but its average cost is lower.

Structural and dynamical patterns on online social networks: the Spanish May 15th movement as a case study.

The number of people using online social networks in their everyday life is continuously growing at a pace never saw before. This new kind of communication has an enormous impact on opinions, cultural trends, information spreading and even in the commercial success of new products. More importantly, social online networks have revealed as a fundamental organizing mechanism in recent country-wide social movements. In this paper, we provide a quantitative analysis of the structural and dynamical patterns emerging from the activity of an online social network around the ongoing May 15th (15M) movement in Spain. Our network is made up by users that exchanged tweets in a time period of one month, which includes the birth and stabilization of the 15M movement. We characterize in depth the growth of such dynamical network and find that it is scale-free with communities at the mesoscale. We also find that its dynamics exhibits typical features of critical systems such as robustness and power-law distributions for several quantities. Remarkably, we report that the patterns characterizing the spreading dynamics are asymmetric, giving rise to a clear distinction between information sources and sinks. Our study represents a first step towards the use of data from online social media to comprehend modern societal dynamics.

Análisis de costes del programa de metadona en la Comunidad Autónoma de La Rioja / Costs-analysis of methadone program in the Autonomous Community La Rioja, Spain

Fundamento: Los programas de dispensación de metadona se han organizado en cada Comunidad Autónoma de una forma específica, desconociéndose sus costes derivados a pesar del interés que puede conllevar una gestión más eficiente. Nuestro estudio tiene por objetivo calcular los costes del programa de metadona en la ComunidadAutónoma de La Rioja. Métodos: El estudio se realizó en 2010. Los datos fueron recogidos a partir de los registros existentes en diferentes instituciones sanitarias, según las diferentes fases del programa. Los costes se clasificaron en función de las diferentes etapas y de los diferentes centros de dispensación. Resultados: El análisis de los datos muestra un coste total anual aproximado de 165.759 € para una concentración de 2 mg/ml de metadona, que significa un coste anual de 412,34 € por paciente . Conclusiones: La fase de dispensación de la metadona es la que mayor coste supone, el centro cuyos pacientes en términos relativos cuestan más al programa es el que cuenta con menor número de pacientes atendidos, debido a los costes fijos que han de repartirse entre menos personas, si bien el centro de Logroño tiene el mayor coste total por atender al mayor número de personas pero su coste medio por paciente es menor(AU)

Background: Methadone programs have been organized in each Spanish region in a specific way. In spite of the regional interests to manage those programs in a more efficient way, so far the costs of the programs are unknown. As a previous step, it would be desirable to understand the activities related to these programs as well as their respective costs. This article aims to calculate the cost of the Methadone program in the autonomous community of La Rioja, and to understand those parameters which generate a greater cost to this programme. Methods: The study followed a similar structure as the research recently applied to the region of Murcia. The reference year for the study of the annual costs of the Methadone program was 2010. Data were obtained fromdifferent registries of several institutions involved in the regional program. Costs were classified according to different stages and dispensation centres which participated in this programme. Results: Data analysis, for a concentration of 2 mg/ml of methadone, showed an approximate annual cost of 165.759 €. Taking the total number of patients into consideration the individual cost was 412,34€. Conclusions: Dispensation is the stage which caused the largest cost to the programme, the highest per patient cost corresponded to the centre with less patients due to the fact that fixed costs are shared by a smaller group of persons; the biggest global cost of the programme came from Logroño’s center but its average cost is lower(AU)