Rapid convergence to frequency for Substitution Tilings of the Plane

This paper concerns self-similar tilings in dimension 2. We consider the number of occurrences of a given tile in any domain bounded by a Jordan curve. For a large class of self-similar tilings, including most known examples, we give estimates of the oscillation of this number of occurrences around its average frequency times the total number of tiles in the domain, which depend only on the Jordan curve.Comment: Minor corrections suggested by the referee. To appear in Communications in Mathematical Physic

Igneous differentiation in porphyry dikes

[Resumen] Se aborda de manera teórica los principales procesos operativos de diferenciación ígnea en secciones transversales de los conductos filonianos, aplicándolo a los diques de pórfido granítico s. 1. del Sistema Central Español. Para estos magmas se deduce un régimen de flujo marcadamente laminar en el conducto (:~ 30 mts. potencia). Estos caracteres impiden tanto la efectividad de franccionamiento cristalino «in situ:\), como grados importantes de asimilación o contaminación en ruta hacia la superficie. Los diques simples, de flujos isoviscosos, van a diferenciarse por fenómenos, principalmente, de flujo ígneo, en ocasiones combinado con la presencia de varios magmas fluyendo a la vez en el mismo pulso (conductos gruesos o flujos veloces). Con estos mecanismos se tenderá a generar evoluciones del tipo félsico a máfico, de borde a centro del dique de pórfido. Los diques compuestos se formarán cuando los magmas son suficientemente contrastados en sus caracteres físicos (viscosidad, p. ej.) y químicos, o cuando son varíos pulsos magmáticos a través del mismo conducto. En estos casos podría haber fen6menos de mezcla magmática si la diferencia de viscosidad es alta y uno de esos magmas es poco viscoso (magmas básicos). En estos casos podrían generarse zonas básicas en el borde, o no, de los diques. de pórfido. En resumen la diferenciación de flujo, la mezcla magmática y la asociación de varios líquidos fluyendo en el mismo conducto (de manera simultánea o por pulsos magmáticos algo separados en el tiempo), parecen ser los mecanismos de diferenciación ígnea más efectivos de estos magmas graníticos que fluyen en angostos conductos filonianos[Abstract] We deal in theoretical way wíth the main differentiation proccesses taking place in dike conducts, applied to the porphyry dikes of the Spanish Central System. For these magmas we infer a strong laminar flow regime (~30 m dike witdh). This, prevent an efficient «in situ:\) cristal fractionation as well as large extent of assimilation-contamination processes during the ascent of the magmas «en route» to more surface levels. Simple dikes, with isoviscous flow, could differentiate mainley by igneous flow. Sometimes this mechanism is combinated with the possibility of severa! Magmas flowing togheter on the same pulse (thick dikes or fast flows). With these mechanisms felsic to mafic evolutions are favoured inward the porphyry dike. Composite dikes are formed when magmas are contrasted enough in their chemical or physical features (p. ej. viscosity), or when different magmatic pulses occur in the same channel. In these conditions commingling of magmas could exist if the viscosity ratio is high apd one of the magmas is very fluid (basic one). These processes could generate basic margins in the porphyry dikes. In short, flow differentiation, magmatic mixing and flowing of associated magmas (simultaneously or by successive pulses), seem to be the more efficient differentiation mechanisms for granitic magmas flowing in narrow dikes

Entropic and enthalpic effects of 4-methoxy substitution in phenoxyl radicals

Values of ΔH_3=(–12.4 ± 1.6) kJ mol^(–1), ΔS_3=(–18.5 ± 5.6) J K^(–1) mol^(–1) for reaction (3) (see text), corresponding to an O–H bond energy of 322.2 kJ mol^(–1) in 1, and to a 14.5 J K^(–1) mol^(–1) entropy loss for the CH_3O–Ar (Ar = aromatic) libration in 2 relative to 1, are derived from the temperature dependence of the equilibrium constant K_3, determined by EPR spectrometry in benzene–toluene media, between 251 and 304 K. These results allow, for the first time, discrimination between enthalpic and entropic effects on the rates of (O)H-atom abstraction by peroxyl radicals from 4-methoxyphenols and related species

Dynamic scaling approach to study time series fluctuations

We propose a new approach for properly analyzing stochastic time series by mapping the dynamics of time series fluctuations onto a suitable nonequilibrium surface-growth problem. In this framework, the fluctuation sampling time interval plays the role of time variable, whereas the physical time is treated as the analog of spatial variable. In this way we found that the fluctuations of many real-world time series satisfy the analog of the Family-Viscek dynamic scaling ansatz. This finding permits to use the powerful tools of kinetic roughening theory to classify, model, and forecast the fluctuations of real-world time series.Comment: 25 pages, 7 figures, 1 tabl

Estimación de rendimientos de soja y maíz a partir de variables edafoclimáticas

Estimación de rendimientos de soja y maíz a partir de variables edafoclimáticasFil: Coronel, Alejandra. Universidad Nacional de Rosario. Facultad de Ciencias Agrarias; Argentin

Accuracy of diabetes screening methods used for people with tuberculosis, Indonesia, Peru, Romania, South Africa

Objective To evaluate the performance of diagnostic tools for diabetes mellitus, including laboratory methods and clinical risk scores, in newly-diagnosed pulmonary tuberculosis patients from four middle-income countries. Methods In a multicentre, prospective study, we recruited 2185 patients with pulmonary tuberculosis from sites in Indonesia, Peru, Romania and South Africa from January 2014 to September 2016. Using laboratory-measured glycated haemoglobin (HbA1c) as the gold standard, we measured the diagnostic accuracy of random plasma glucose, point-of-care HbA1c, fasting blood glucose, urine dipstick, published and newly derived diabetes mellitus risk scores and anthropometric measurements. We also analysed combinations of tests, including a two-step test using point-of-care HbA1cwhen initial random plasma glucose was ≥ 6.1 mmol/L. Findings The overall crude prevalence of diabetes mellitus among newly diagnosed tuberculosis patients was 283/2185 (13.0%; 95% confidence interval, CI: 11.6–14.4). The marker with the best diagnostic accuracy was point-of-care HbA1c (area under receiver operating characteristic curve: 0.81; 95% CI: 0.75–0.86). A risk score derived using age, point-of-care HbA1c and random plasma glucose had the best overall diagnostic accuracy (area under curve: 0.85; 95% CI: 0.81–0.90). There was substantial heterogeneity between sites for all markers, but the two-step combination test performed well in Indonesia and Peru. Conclusion Random plasma glucose followed by point-of-care HbA1c testing can accurately diagnose diabetes in tuberculosis patients, particularly those with substantial hyperglycaemia, while reducing the need for more expensive point-of-care HbA1c testing. Risk scores with or without biochemical data may be useful but require validation