Detecting Determinism in High Dimensional Chaotic Systems

A method based upon the statistical evaluation of the differentiability of the measure along the trajectory is used to identify in high dimensional systems. The results show that the method is suitable for discriminating stochastic from deterministic systems even if the dimension of the latter is as high as 13. The method is shown to succeed in identifying determinism in electro-encephalogram signals simulated by means of a high dimensional system.Comment: 8 pages (RevTeX 3 style), 5 EPS figures, submitted to Phys. Rev. E (25 apr 2001

Using Topological Statistics to Detect Determinism in Time Series

Statistical differentiability of the measure along the reconstructed trajectory is a good candidate to quantify determinism in time series. The procedure is based upon a formula that explicitly shows the sensitivity of the measure to stochasticity. Numerical results for partially surrogated time series and series derived from several stochastic models, illustrate the usefulness of the method proposed here. The method is shown to work also for high--dimensional systems and experimental time seriesComment: 23 RevTeX pages, 14 eps figures. To appear in Physical Review

Does intensification result in higher efficiency and sustainability? An emergy analysis of Mediterranean sheep-crop farming systems

The embodiment of resources in agricultural products depends on the way they are made, i.e., the production system. We applied emergy analysis on three contrasting sheep-crop farming systems according to different degrees of specialization, integration and intensification of production in Mediterranean Spain. We studied emergy flows, transformity values and emergy indices at the system level and per product (lamb meat; permanent crops: rainfed olive and almond; arable crops: rainfed barley, irrigated barley, alfalfa and sunflower). We found that the specialized pasture-based sheep system had the lowest intensity and efficiency and the highest sustainability, as opposite to the partially-integrated mixed system, while the fully-integrated mixed system obtained a balanced position. Lamb meat production was 1.9 and 1.3 times more intensive and efficient, respectively, in the partially-integrated mixed system than in the pasture-based sheep system, but 5.1 times less sustainable. All sheep sub-systems had comparatively lower intensity and higher sustainability than crops due to their higher capacity to use local and renewable natural resources. Our findings suggest that further support of agricultural development based on local and renewable natural resources and best practices is necessary to ensure long-term farming sustainability and social welfare

Kilohertz-resolution spectroscopy of cold atoms with an optical frequency comb

We have performed sub-Doppler spectroscopy on the narrow intercombination line of cold calcium atoms using the amplified output of a femtosecond laser frequency comb. Injection locking of a 657-nm diode laser with a femtosecond comb allows for two regimes of amplification, one in which many lines of the comb are amplified, and one where a single line is predominantly amplified. The output of the laser in both regimes was used to perform kilohertz-level spectroscopy. This experiment demonstrates the potential for high-resolution absolute-frequency spectroscopy over the entire spectrum of the frequency comb output using a single high-finesse optical reference cavity.Comment: 4 pages, 4 Figure

VIVA II: a community-academic partnership promoting access to and consumption of water in a tri-ethnic community in rural New Mexico.

Presented at: American Public Health Association 2016 Annual Meeting & Expo; October 29-November 2, 2016; Denver, CO.https://digitalrepository.unm.edu/prc-posters-presentations/1025/thumbnail.jp

The speciation of inorganic carbon in estuarine and interstitial waters

A calculation procedure to obtain pH, total alkalinity and concentration of inorganic carbon, based on the application of Gran functions, is described. An iterative program was used to optimise the electrode standard potential (E₀) and inorganic carbon concentration. Alkalinities higher than 15 mM were detected in interstitial waters from sediments collected in Cadiz Bay. A contribution of 20 % was associated with those acid-based species other than inorganic carbon. Speciation of inorganic carbon in estuarine waters was characterised using laboratory simulation techniques. Total carbonate and alkalinity, as well as inorganic carbon concentration, present conservative behaviour in the mixing process of waters having different salinities.En este trabajo se presenta un procedimiento de cálculo para la obtención del pH, alcalinidad total y concentración de carbono inorgánico, basado en la aplicación de funciones de Gran. Para ello, se ha utilizado un programa iterativo que optimiza el potencial estándar del electrodo y la concentración de carbono inorgánico. Mediante la aplicación de este método se muestran algunas características del sistema del carbónico en el agua intersticial y en sistemas estuáricos. En el agua intersticial de los sedimentos de la bahía de Cádiz se han detectado alcalinidades superiores a 15 mM a profundidades mayores de 10 cm, existiendo una contribución de hasta un 20 % de especies con carácter ácido-base diferentes al carbono inorgánico. La especiación del carbono inorgánico en aguas estuáricas se ha caracterizado utilizando técnicas de simulación en el laboratorio. Se ha observado que tanto la alcalinidad total, como la alcalinidad de carbonato y la concentración de carbono inorgánico presentan un comportamiento conservativo en procesos de mezcla de aguas de diferentes salinidades.Instituto Español de Oceanografí

The role of ammonia in sulfuric acid ion induced nucleation

We have developed a new multi-step strategy for quantum chemical calculations on atmospherically relevant cluster structures that makes calculation for large clusters affordable with a good accuracy-to-computational effort ratio. We have applied this strategy to evaluate the relevance of ternary ion induced nucleation; we have also performed calculations for neutral ternary nucleation for comparison. The results for neutral ternary nucleation agree with previous results, and confirm the important role of ammonia in enhancing the growth of sulfuric acid clusters. On the other hand, we have found that ammonia does not enhance the growth of ionic sulfuric acid clusters. The results also confirm that ion-induced nucleation is a barrierless process at high altitudes, but at ground level there exists a barrier due to the presence of a local minimum on the free energy surface

Evaluation of radiography as a screening method for detection and characterisation of congenital vertebral malformations in dogs

Congenital vertebral malformations (CVM) are common in brachycephalic ‘screw-tailed’ dogs; they can be associated with neurological deficits and a genetic predisposition has been suggested. The purpose of this study was to evaluate radiography as a screening method for congenital thoracic vertebral malformations in brachycephalic ‘screw-tailed’ dogs by comparing it with CT. Forty-nine dogs that had both radiographic and CT evaluations of the thoracic vertebral column were included. Three observers retrospectively reviewed the images independently to detect CVMs. When identified, they were classified according to a previously published radiographic classification scheme. A CT consensus was then reached. All observers identified significantly more affected vertebrae when evaluating orthogonal radiographic views compared with lateral views alone; and more affected vertebrae with the CT consensus compared with orthogonal radiographic views. Given the high number of CVMs per dog, the number of dogs classified as being CVM free was not significantly different between CT and radiography. Significantly more midline closure defects were also identified with CT compared with radiography. Malformations classified as symmetrical or ventral hypoplasias on radiography were frequently classified as ventral and medial aplasias on CT images. Our results support that CT is better than radiography for the classification of CVMs and this will be important when further evidence of which are the most clinically relevant CVMs is identified. These findings are of particular importance for designing screening schemes of CVMs that could help selective breeding programmes based on phenotype and future studies