4,248 research outputs found

    Accelerating the convergence of AFETI partitioned analysis of heterogeneous structural dynamical systems

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    Variationally based algorithms for the partitioned solution of structural mechanics problems are presented. Two key features of the present algorithms are the judicious application of the d’Alembert-Lagrange principal equations and the use of dominant substructural deformation modes. The paper includes three developments: 1. Variational derivation of AFETI parallel solution methods. 2. One-level and two-level AFETI implicit transient analysis algorithms with coarse problem included in the projector and based on free floating rigid body modes. 3. A new AFETI implicit transient solution algorithm derived by constraining the interface equilibrium equations with the floating and dominant deformational modes. In addition to variational derivations of solution algorithms, the present paper is strived to offer new physical and/or numerical insight as each of variational derivational steps is succinctly explained. Performance evaluations of the algorithms described herein are presented

    Compound orbits break-up in constituents: an algorithm

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    In this paper decomposition of periodic orbits in bifurcation diagrams are derived in unidimensional dynamics system xn+1=f(xn;r)x_{n+1}=f(x_{n};r), being ff an unimodal function. We proof a theorem which states the necessary and sufficient conditions for the break-up of compound orbits in their simpler constituents. A corollary to this theorem provides an algorithm for the computation of those orbits. This process closes the theoretical framework initiated in (Physica D, 239:1135--1146, 2010)

    Pigmented corneal ring associated with orthokeratology in caucasians : case reports

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    BACKGROUND: The aim was to report the appearance of a pigmented ring in both eyes of two patients undergoing overnight orthokeratology. METHODS: Two Caucasian patients, one male and one female, were fitted with orthokeratology lenses to correct myopia between -2.00 and -2.50 DS with Paragon corneal refractive therapy lenses worn overnight. Treatment was successful in both patients achieving uncorrected vision of 6/6 or better monocularly under high (100 per cent) and low (10 per cent) contrast conditions. RESULTS: At the six-month visit both patients presented with pigmented rings under slitlamp examination in both eyes. The location of the ring was consistent with the corneal area being flattened for myopic correction. Clinical examination was otherwise normal. CONCLUSIONS: Despite being initially reported in Asian patients from Hong Kong, a pigmented ring related to orthokeratology treatment is also present in Caucasian patients, reducing the potential role of an ethnic link. Further large-scale studies need to be done to estimate the actual incidence of this condition and the potential implications for corneal health

    Soil health—a new challenge for microbiologists and chemists

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    Soil health refers to the biological, chemical, and physical features of soil that are essential to long-term, sustainable agricultural productivity with minimal environmental impact. Thus, soil health provides an overall picture of soil functionality. Although it cannot be measured directly, soil health can be inferred by measuring specific soil properties (e.g. organic matter content) and by observing soil status (e.g. fertility). There is also increased interest in studying soil microorganisms in their particular environments, as microbial diversity is intimately related to soil structure and function. One of the key objectives in determining soil health is to acquire indicators that can be used to evaluate the soil’s current status and hence to develop sustainable agricultural systems. In this regard, significant progress has been made over the last few years in the development of specific biomarkers and macromolecular probes, enabling rapid and reliable measurements of soil microbial communities. In addition, modern molecular biological techniques, such as fluorescence in situ hybridization (FISH), reverse transcriptase polymerase chain reaction (RT-PCR), denaturing gradient gel electrophoresis (DGGE), and terminal restriction fragment length polymorphism (T-RFLP), have facilitated the analysis of microbial biodiversity and activity, whereas the application of modern analytical techniques, such as nuclear magnetic resonance (NMR) and pyrolysisgas chromatography-mass spectrometry (Py-GC-MS), have provided data on soil chemistry. The combination of these two approaches offers promise in determining soil health status. [Int Microbiol 2005; 8(1):13-21

    Topographic paracentral corneal thickness with pentacam and orbscan: effect of acoustic factor

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    Purpose: To evaluate the effect of an acoustic factor (AF) on the comparison of central corneal thickness (CCT) and peripheral corneal thickness (PCT) measurements with Orbscan II and Pentacam. Methods: The CCT and PCT at 1, 2, and 3 radial distances from the corneal apex were measured using Orbscan II and Pentacam in 22 right eyes of 22 healthy adults (7 men, 15 women). Three measures were obtained from each 1 of the 25 points measured and then compared to gauge the agreement between both devices at the corneal center and anular areas located at 1-, 2-, and 3-mm distances from the central measurement. Orbscan II readings were considered with and without an AF correction. Results: Pentacam provides statistically significant higher values than Orbscan II does at all the 25 locations analyzed (P,0.001). With a few exceptions, the average difference was fairly constant between 20 and 40 mm for all the corneal locations. A high correlation existed between central readings (r2=0.927; P,0.001) and average thickness at each one of the annular areas being analyzed (r2=0.897 at 1 mm, r2=0.876 at 2 mm, and r2=0.870 at 3 mm); Pentacam minus Orbscan II value averaged for all the points changed from 228610 to 22269 mm after the removal of the AF in Orbscan II. Conclusions: Central and peripheral measurements of the corneal thickness obtained with Orbscan II and Pentacam are significantly different. The removal of the AF in Orbscan II renders lower mean differences but decreases the agreement between both systems and potentially induces an overestimation of CCT and PCT by Orbsan II compared with Pentacam.Supported by national grant PI081380 from Instituto de Salud Carlos III, Spain granted to Ocular Surface and Contact Lens Research Group GI-1750

    Organic carbon and environmental quality of riverine and off-shore sediments from the Gulf of Cádiz, Spain

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    6 páginas, 2 figuras, 3 tablas, 14 referencias.-- [email protected] we show that heavy metal geoaccumulation is apparent in the Tinto and Odiel estuary and, at a lower magnitude, in off-shore sediments. Values above probable effects level (PEL) are recorded for As, Cu, Hg, Pb and Zn in the Tinto and Odiel estuary, for As and Hg in the associated off-shore sediments and for As in the Guadiana River. Significant correlations were found between total organic carbon (TOC) and Cr, Cu, Ni and Zn in the Tinto and Odiel estuary, and Cr, Cu, Ni, Pb, Hg and As in the Guadiana River. PCA analysis differentiated the three studied locations.Peer reviewe

    Infecciones orofaciales de origen odontogénico

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    La naturaleza polimicrobiana de las infecciones odontógenas así como la heterogeneidad de los cuadros clínicos asociados son consecuencia de la diversidad de la microbiota bucal y de la complejidad anatómica y funcional de la cavidad oral. Así mismo, estos procesos pueden dar lugar a múltiples complicaciones que pueden limitarse a afecciones locales o derivar hasta compromisos sistémicos. En el tratamiento farmacológico de estas infecciones es crucial la elección del antibiótico y la pauta posológica más eficaces. La farmacodinamia proporciona los parámetros que hacen posible valorar como varía la actividad de los antibióticos en función del tiempo. Como norma general, en el manejo inicial de las infecciones orofaciales en el adulto, incluidas las infecciones odontógenas, se utilizará amoxicilina/ac. Clavulánico en dosis de 875 mg de amoxicilina y 125 mg de ac. clavulánico pautado cada 8 horas. El cumplimiento terapéutico es clave para evitar la aparición de resistencias, por lo que se ha de maximizar la aceptación por parte de los pacientes. En este sentido se ha demostrado que la nueva presentación de 2000/125 mg de Augmentine Plus pautado cada 12 horas tanto en profilaxis como tratamiento disminuye significativamente la tasa de complicaciones infecciosas derivada de la extracción del tercer molar.The polymicrobial nature of the odontogenic infections as well as the variety of associated conditions are a consequence of the diversity of the buccal microbiota and the anatomical and functional complexity of the oral cavity. In addition to this, all these processes can give way to multiple complications which range from the local to the systemic level. The appropriate choice of antibiotic and posology is crucial in the successful management of these infections. Pharmacodynamics provides those parameters that make it possible to assess how antibiotics activity varies in time. As a general rule, the first step in the initial management of orofacial infections in adults, included odontogenic infections, will be the administration of 875 mg of amoxicillin and 125 mg of clavulanic every 8 hours. Therapeutic compliance is paramount to avoid resistance, therefore patient's acceptance must be sought. In this sense, it has been proved that Augmentine Plus (2000/125) every twelve hours both as profylaxis and as treatment significantly decreases the rate of infective complications associated to extraction of the third molar
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