Superdiffusion in Decoupled Continuous Time Random Walks

Continuous time random walk models with decoupled waiting time density are studied. When the spatial one jump probability density belongs to the Levy distribution type and the total time transition is exponential a generalized superdiffusive regime is established. This is verified by showing that the square width of the probability distribution (appropriately defined)grows as $t^{2/\gamma}$ with $0<\gamma\leq2$ when $t\to \infty$. An important connection of our results and those of Tsallis' nonextensive statistics is shown. The normalized q-expectation value of $x^2$ calculated with the corresponding probability distribution behaves exactly as $t^{2/\gamma}$ in the asymptotic limit.Comment: 9 pages (.tex file), 1 Postscript figures, uses revtex.st

Reaction rate in an evanescent random walkers system

Diffusion mediated reaction models are particularly ubiquitous in the description of phys-ical, chemical or biological processes. The random walk schema is a useful tool for formu-lating these models. Recently, evanescent random walk models have received attention inorder to include finite lifetime processes. For instance, activated chemical reactions, such as laser photolysis, exhibit a different asymptotic limit when compared with immortal walker models. A diffusion limited reaction model based on a one dimensional continuous time random walk on a lattice with evanescent walkers is presented here. The absorption probability density and the reaction rate are analytically calculated in the Laplace domain.A finite absorption rate is considered, a model usually referred to as imperfect trapping.Short and long time behaviors are analyzed.publishedVersionFil: Ré, Miguel Ángel. Universidad Tecnológica Nacional. Facultad Regional Córdoba; Argentina.Fil: Ré, Miguel Ángel. Universidad Nacional de Córdoba. Facultad de Matemática, Astronomía y Física; Argentina.Fil: Bustos, Natalia Carolina. Universidad Nacional de Córdoba. Facultad de Matemática, Astronomía y Física; Argentina.Otras Ciencias Física

Evaluating semi-supervision methods for medical image segmentation: applications in cardiac magnetic resonance imaging

PURPOSE: Purpose Neural networks have potential to automate medical image segmentation but require expensive labeling efforts. While methods have been proposed to reduce the labeling burden, most have not been thoroughly evaluated on large, clinical datasets or clinical tasks. We propose a method to train segmentation networks with limited labeled data and focus on thorough network evaluation. APPROACH: We propose a semi-supervised method that leverages data augmentation, consistency regularization, and pseudolabeling and train four cardiac magnetic resonance (MR) segmentation networks. We evaluate the models on multiinstitutional, multiscanner, multidisease cardiac MR datasets using five cardiac functional biomarkers, which are compared to an expert’s measurements using Lin’s concordance correlation coefficient (CCC), the within-subject coefficient of variation (CV), and the Dice coefficient. RESULTS: The semi-supervised networks achieve strong agreement using Lin’s CCC (>0.8), CV similar to an expert, and strong generalization performance. We compare the error modes of the semi-supervised networks against fully supervised networks. We evaluate semi-supervised model performance as a function of labeled training data and with different types of model supervision, showing that a model trained with 100 labeled image slices can achieve a Dice coefficient within 1.10% of a network trained with 16,000+ labeled image slices. CONCLUSION: We evaluate semi-supervision for medical image segmentation using heterogeneous datasets and clinical metrics. As methods for training models with little labeled data become more common, knowledge about how they perform on clinical tasks, how they fail, and how they perform with different amounts of labeled data is useful to model developers and users

Propuesta de reacondicionamiento termo-energético en tipología escolar localizada en el área metropolitana de San Juan

Posteriormente al terremoto de 1944 acaecido en San Juan, fueron construidas bajo normativas del “Consejo de Reconstrucción” una serie de escuelas, entre las cuales se destaca la tipología en peine doble materializada por el Arq. Ramos Correa. Estos establecimientos deben remodelarse para adecuarlos a requerimientos físicos y funcionales de la actualidad, siendo el momento oportuno para dar también soluciones tecnológicas a componentes de la envolvente, que mejoren su comportamiento termo-energético. A tal fin, se desarrolla un procedimiento utilizando modelos de simulación que evalúan el desempeño del edificio antes y después de cambios propuestos, verificando el cumplimiento de los valores admisibles de las Normas IRAM. Con las mejoras planteadas la energía necesaria para calefacción disminuye entre 28% y 50%, cumpliendo los valores admisibles de la Transmitancia Térmica en calidad edilicia “B”. Las contribuciones se centran en lo metodológico-instrumental, y en lo tecnológico termo-energético para su transferencia inmediata a los organismos pertinentes.After the 1944 occurred earthquake in San Juan, a number of schools were built under regulations of the "Reconstruction Council", among them the “double comb” typology materialized by Arch. Ramos Correa stands out. These establishments should be refurbished to suit today´s physical and functional requirements, being the right time to also give technological solutions to envelope components, which improve their thermal-energy performance. Aimed to this, a method is developed using simulation models to evaluate the building performance before and after the proposed changes, to verify compliance with the permissible values of the IRAM Standards. With the proposed constructive improvements, the required energy for heating is reduced between 28% and 50% fulfilling the allowable values of the Thermal Transmittance at “B” building quality. The contributions are focused on instrumental-methodological aspects, and on those technological referred to thermalenergy efficiency, for its immediate transfer to the relevant agencies.Tema 5: Arquitectura ambientalmente consciente.Facultad de Arquitectura y Urbanism

Propuesta de reacondicionamiento termo-energético en tipología escolar localizada en el área metropolitana de San Juan

Posteriormente al terremoto de 1944 acaecido en San Juan, fueron construidas bajo normativas del “Consejo de Reconstrucción” una serie de escuelas, entre las cuales se destaca la tipología en peine doble materializada por el Arq. Ramos Correa. Estos establecimientos deben remodelarse para adecuarlos a requerimientos físicos y funcionales de la actualidad, siendo el momento oportuno para dar también soluciones tecnológicas a componentes de la envolvente, que mejoren su comportamiento termo-energético. A tal fin, se desarrolla un procedimiento utilizando modelos de simulación que evalúan el desempeño del edificio antes y después de cambios propuestos, verificando el cumplimiento de los valores admisibles de las Normas IRAM. Con las mejoras planteadas la energía necesaria para calefacción disminuye entre 28% y 50%, cumpliendo los valores admisibles de la Transmitancia Térmica en calidad edilicia “B”. Las contribuciones se centran en lo metodológico-instrumental, y en lo tecnológico termo-energético para su transferencia inmediata a los organismos pertinentes.After the 1944 occurred earthquake in San Juan, a number of schools were built under regulations of the "Reconstruction Council", among them the “double comb” typology materialized by Arch. Ramos Correa stands out. These establishments should be refurbished to suit today´s physical and functional requirements, being the right time to also give technological solutions to envelope components, which improve their thermal-energy performance. Aimed to this, a method is developed using simulation models to evaluate the building performance before and after the proposed changes, to verify compliance with the permissible values of the IRAM Standards. With the proposed constructive improvements, the required energy for heating is reduced between 28% and 50% fulfilling the allowable values of the Thermal Transmittance at “B” building quality. The contributions are focused on instrumental-methodological aspects, and on those technological referred to thermalenergy efficiency, for its immediate transfer to the relevant agencies.Tema 5: Arquitectura ambientalmente consciente.Facultad de Arquitectura y Urbanism

Direct powder extrusion 3d printing of praziquantel to overcome neglected disease formulation challenges in paediatric populations

For the last 40 years, praziquantel has been the standard treatment for schistosomiasis, a neglected parasitic disease affecting more than 250 million people worldwide. However, there is no suitable paediatric formulation on the market, leading to off-label use and the splitting of commercial tablets for adults. In this study, we use a recently available technology, direct powder extrusion (DPE) three-dimensional printing (3DP), to prepare paediatric Printlets™ (3D printed tablets) of amorphous solid dispersions of praziquantel with Kollidon® VA 64 and surfactants (Span™ 20 or Kolliphor® SLS). Printlets were successfully printed from both pellets and powders obtained from extrudates by hot melt extrusion (HME). In vitro dissolution studies showed a greater than four-fold increase in praziquantel release, due to the formation of amorphous solid dispersions. In vitro palatability data indicated that the printlets were in the range of praziquantel tolerability, highlighting the taste masking capabilities of this technology without the need for additional taste masking excipients. This work has demonstrated the possibility of 3D printing tablets using pellets or powder forms obtained by HME, avoiding the use of filaments in fused deposition modelling 3DP. Moreover, the main formulation hurdles of praziquantel, such as low drug solubility, inadequate taste, and high and variable dose requirements, can be overcome using this technology

QuickSel: Quick Selectivity Learning with Mixture Models

Estimating the selectivity of a query is a key step in almost any cost-based query optimizer. Most of today's databases rely on histograms or samples that are periodically refreshed by re-scanning the data as the underlying data changes. Since frequent scans are costly, these statistics are often stale and lead to poor selectivity estimates. As an alternative to scans, query-driven histograms have been proposed, which refine the histograms based on the actual selectivities of the observed queries. Unfortunately, these approaches are either too costly to use in practice---i.e., require an exponential number of buckets---or quickly lose their advantage as they observe more queries. In this paper, we propose a selectivity learning framework, called QuickSel, which falls into the query-driven paradigm but does not use histograms. Instead, it builds an internal model of the underlying data, which can be refined significantly faster (e.g., only 1.9 milliseconds for 300 queries). This fast refinement allows QuickSel to continuously learn from each query and yield increasingly more accurate selectivity estimates over time. Unlike query-driven histograms, QuickSel relies on a mixture model and a new optimization algorithm for training its model. Our extensive experiments on two real-world datasets confirm that, given the same target accuracy, QuickSel is 34.0x-179.4x faster than state-of-the-art query-driven histograms, including ISOMER and STHoles. Further, given the same space budget, QuickSel is 26.8%-91.8% more accurate than periodically-updated histograms and samples, respectively

LDM: Lineage-Aware Data Management in Multi-tier Storage Systems

We design and develop LDM, a novel data management solution to cater the needs of applications exhibiting the lineage property, i.e. in which the current writes are future reads. In such a class of applications, slow writes significantly hurt the over-all performance of jobs, i.e. current writes determine the fate of next reads. We believe that in a large scale shared production cluster, the issues associated due to data management can be mitigated at a way higher layer in the hierarchy of the I/O path, even before requests to data access are made. Contrary to the current solutions to data management which are mostly reactive and/or based on heuristics, LDM is both deterministic and pro-active. We develop block-graphs, which enable LDM to capture the complete time-based data-task dependency associations, therefore use it to perform life-cycle management through tiering of data blocks. LDM amalgamates the information from the entire data center ecosystem, right from the application code, to file system mappings, the compute and storage devices topology, etc. to make oracle-like deterministic data management decisions. With trace-driven experiments, LDM is able to achieve 29–52% reduction in over-all data center workload execution time. Moreover, by deploying LDM with extensive pre-processing creates efficient data consumption pipelines, which also reduces write and read delays significantly

Características epidemiológicas y moleculares de <i>Chlamydia psittaci</i> provenientes de 8 casos humanos de psitacosis y de 4 aves relacionadas en la Argentina

In Argentina, the epidemiological and molecular characteristics of Chlamydia psittaci infections are still not sufficiently known. A total of 846 respiratory and 10 ocular samples from patients with suspected human psittacosis were tested for C. psittaci from January 2010 to March 2015. Four samples of birds related to these patients were also studied. Forty-eight samples were positive for C. psittaci by a nested PCR. The molecular characterization of twelve C. psittaci PCR-positive samples received in the National Reference Laboratory INEI-ANLIS “Dr. Carlos G. Malbrán”, Buenos Aires, Argentina was performed. Eight positive samples from humans and four from birds were genotyped by ompA gene sequencing. C. psittaci genotype A was found in all human samples and in the related birds. This report contributes to our increasing knowledge of the epidemiological and molecular characteristics of C. psittaci to conduct effective surveillance of its zoonotic infections.En la Argentina, aún no se conocen suficientemente las características epidemiológicas y moleculares de las infecciones por Chlamydia psittaci. Entre enero del 2010 y marzo del 2015 se estudiaron 846 muestras respiratorias y 10 oculares de pacientes con sospecha de psitacosis para la búsqueda de C. psittaci. También se estudiaron 4 muestras de aves relacionadas con estos pacientes. De ese total, 48 muestras fueron positivas para C. psittaci mediante una reacción en cadena de la polimerasa (PCR) anidada. Posteriormente, se realizó en el INEI-ANLIS «Dr. Carlos G. Malbrán» la caracterización molecular de 12 muestras positivas para C. psittaci, 8 de humanos y 4 de aves, que fueron genotipificadas por secuenciación del gen ompA. C. psittaci genotipo A se encontró en todas esas muestras. Este informe contribuye a mejorar nuestro conocimiento de las características epidemiológicas y moleculares de C. psittaci para lograr una vigilancia efectiva de la zoonosis que produce.Facultad de Ciencias Veterinaria