Sobre la dependencia del hábito cristalino respecto de la hidrodinámica del medio en que crece el cristal, referido al caso del NaCl

Se describe un modelo explicativo de la modificación de hábito de los cristales de NaCl, por acción de la hidrodinámica de la solución madre, basado en los diferentes mecanismos de aporte sobre caras homólogas

Facilitating the interaction with data warehouse schemas through a visual web-based approach

In most respects, there are implicit drawbacks concerning representation and interaction with data in relational-database applications. On the one hand, there is a lack of expressiveness and ease of use in the user interfaces that handle such data. On the other hand, there is an implicit need for interactive end-user visual tools to query data and avoid dependency on programming languages. The main aim of this work is to study the problem of database interaction and usability, comparing existing solutions and providing a new approach that overcomes existing problems. We propose a web-based tool that manipulates Data Warehouse schemas by using a visual language to represent the database structure and providing several visualization techniques that facilitate the interaction and creation of queries involving different levels of complexity. We based our research on an End-User Development approach that has been evaluated to obtain some initial usability indicators

Responses of Coccidia-Vaccinated Broilers to Essential Oil Blends Supplementation up to Forty-Nine Days of Age

Coccidiosis control may become a greater problem as the use of growth-promoting antibiotics (GPA) and ionophores declines. Vaccination with live oocysts may turn into a popular alternative to the use of coccidiostats in broilers, although cocci vaccination is frequently linked to temporary lower performance in young flocks. This experiment evaluates the dietary supplementation of 2 specific essential oil (EO) blends (Crina Poultry and Crina Alternate), either as alternatives to GPA and ionophores (BMD + Coban) or as feed additives that help to improve the performance of cocci-vaccinated broilers. Live performance and lesion scores were observed. These 2 specific EO blends differ in their efficacy to promote growth. Chickens that were not cocci vaccinated and were fed Crina Poultry had better feed conversion ratio (FCR) than the unmedicated control treatment in the starter period. The same EO improved FCR in cocci-vaccinated birds in the finisher period in comparison to the negative control group, but those responses were not significantly different from other treatments or significant at 49 d of age. No significant differences were observed in lesion scores at 37 d. Diets supplemented with a GPA-ionophore combination consistently supported the best BW gain and FCR in each period and the entire grow-out period. No significant beneficial or deleterious effects on live performance were observed due to these specific EO blends in cocci-vaccinated broilers

Using step width to compare locomotor biomechanics between extinct, non-avian theropod dinosaurs and modern obligate bipeds

How extinct, non-avian theropod dinosaurs locomoted is a subject of considerable interest, as is the manner in which it evolved on the line leading to birds. Fossil footprints provide the most direct evidence for answering these questions. In this study, step width—the mediolateral (transverse) distance between successive footfalls—was investigated with respect to speed (stride length) in non-avian theropod trackways of Late Triassic age. Comparable kinematic data were also collected for humans and 11 species of ground-dwelling birds. Permutation tests of the slope on a plot of step width against stride length showed that step width decreased continuously with increasing speed in the extinct theropods (p < 0.001), as well as the five tallest bird species studied (p < 0.01). Humans, by contrast, showed an abrupt decrease in step width at the walk–run transition. In the modern bipeds, these patterns reflect the use of either a discontinuous locomotor repertoire, characterized by distinct gaits (humans), or a continuous locomotor repertoire, where walking smoothly transitions into running (birds). The non-avian theropods are consequently inferred to have had a continuous locomotor repertoire, possibly including grounded running. Thus, features that characterize avian terrestrial locomotion had begun to evolve early in theropod history

Chelator free gallium-68 radiolabelling of silica coated iron oxide nanorods via surface interactions

The commercial availability of combined magnetic resonance imaging (MRI)/positron emission tomography (PET) scanners for clinical use has increased demand for easily prepared agents which offer signal or contrast in both modalities. Herein we describe a new class of silica coated iron–oxide nanorods (NRs) coated with polyethylene glycol (PEG) and/or a tetraazamacrocyclic chelator (DO3A). Studies of the coated NRs validate their composition and confirm their properties as in vivo T₂ MRI contrast agents. Radiolabelling studies with the positron emitting radioisotope gallium-68 (t1/2 = 68 min) demonstrate that, in the presence of the silica coating, the macrocyclic chelator was not required for preparation of highly stable radiometal-NR constructs. In vivo PET-CT and MR imaging studies show the expected high liver uptake of gallium-68 radiolabelled nanorods with no significant release of gallium-68 metal ions, validating our innovation to provide a novel simple method for labelling of iron oxide NRs with a radiometal in the absence of a chelating unit that can be used for high sensitivity liver imaging

Feasible database querying using a visual end-user approach

This is the author's version of the work. It is posted here for your personal use. Not for redistribution. The definitive Version of Record was published in Proceedings of the 2nd ACM SIGCHI symposium on Engineering interactive computing systems, http://dx.doi.org/10.1145/1822018.1822047Querying databases is a common daily task carried out by a great deal of end-users who do not have specific skills in SQL language. Today, most of the database interaction is achieved by means of query interfaces provided by the database environment. However, most of these interfaces suffer from expressive limitations, since they are mostly based on metaphors that drastically restrict the expressiveness of the SQL language that is generated and executed in the background. In this paper, we present a visual interaction language and tool focused on easily querying databases by end-users. We make no assumption on the level of the user's experience with query languages, as our visual metaphor is intended for querying databases by unskilled end-users and also leveraging the restriction on the expressiveness of the queries created by them. We also report on some late braking results obtained by an experiment carried out with real users.The work reported in this paper is being partially supported by the founded projects TIN2008-02081/TIN and S2009/TIC-1650

Advanced Automata Minimization

We present an efficient algorithm to reduce the size of nondeterministic Buchi word automata, while retaining their language. Additionally, we describe methods to solve PSPACE-complete automata problems like universality, equivalence and inclusion for much larger instances (1-3 orders of magnitude) than before. This can be used to scale up applications of automata in formal verification tools and decision procedures for logical theories. The algorithm is based on new transition pruning techniques. These use criteria based on combinations of backward and forward trace inclusions. Since these relations are themselves PSPACE-complete, we describe methods to compute good approximations of them in polynomial time. Extensive experiments show that the average-case complexity of our algorithm scales quadratically. The size reduction of the automata depends very much on the class of instances, but our algorithm consistently outperforms all previous techniques by a wide margin. We tested our algorithm on Buchi automata derived from LTL-formulae, many classes of random automata and automata derived from mutual exclusion protocols, and compared its performance to the well-known automata tool GOAL.Comment: 15 page

Foot pressure distributions during walking in African elephants (Loxodonta africana)

Elephants, the largest living land mammals, have evolved a specialized foot morphology to help reduce locomotor pressures while supporting their large body mass. Peak pressures that could cause tissue damage are mitigated passively by the anatomy of elephants' feet, yet this mechanism does not seem to work well for some captive animals. This study tests how foot pressures vary among African and Asian elephants from habitats where natural substrates predominate but where foot care protocols differ. Variations in pressure patterns might be related to differences in husbandry, including but not limited to trimming and the substrates that elephants typically stand and move on. Both species' samples exhibited the highest concentration of peak pressures on the lateral digits of their feet (which tend to develop more disease in elephants) and lower pressures around the heel. The trajectories of the foot's centre of pressure were also similar, confirming that when walking at similar speeds, both species load their feet laterally at impact and then shift their weight medially throughout the step until toe-off. Overall, we found evidence of variations in foot pressure patterns that might be attributable to husbandry and other causes, deserving further examination using broader, more comparable samples

Towards a definition of quantum integrability

We briefly review the most relevant aspects of complete integrability for classical systems and identify those aspects which should be present in a definition of quantum integrability. We show that a naive extension of classical concepts to the quantum framework would not work because all infinite dimensional Hilbert spaces are unitarily isomorphic and, as a consequence, it would not be easy to define degrees of freedom. We argue that a geometrical formulation of quantum mechanics might provide a way out.Comment: 37 pages, AmsLatex, 1 figur