Adaptive Finite Element Solution of Multiscale PDE-ODE Systems

We consider adaptive finite element methods for solving a multiscale system consisting of a macroscale model comprising a system of reaction-diffusion partial differential equations coupled to a microscale model comprising a system of nonlinear ordinary differential equations. A motivating example is modeling the electrical activity of the heart taking into account the chemistry inside cells in the heart. Such multiscale models pose extremely computationally challenging problems due to the multiple scales in time and space that are involved. We describe a mathematically consistent approach to couple the microscale and macroscale models based on introducing an intermediate "coupling scale". Since the ordinary differential equations are defined on a much finer spatial scale than the finite element discretization for the partial differential equation, we introduce a Monte Carlo approach to sampling the fine scale ordinary differential equations. We derive goal-oriented a posteriori error estimates for quantities of interest computed from the solution of the multiscale model using adjoint problems and computable residuals. We distinguish the errors in time and space for the partial differential equation and the ordinary differential equations separately and include errors due to the transfer of the solutions between the equations. The estimate also includes terms reflecting the sampling of the microscale model. Based on the accurate error estimates, we devise an adaptive solution method using a "blockwise" approach. The method and estimates are illustrated using a realistic problem.Comment: 25 page

Ewald methods for inverse power-law interactions in tridimensional and quasi-two dimensional systems

In this paper, we derive the Ewald method for inverse power-law interactions in quasi-two dimensional systems. The derivation is done by using two different analytical methods. The first uses the Parry's limit, that considers the Ewald methods for quasi-two dimensional systems as a limit of the Ewald methods for tridimensional systems, the second uses Poisson-Jacobi identities for lattice sums. Taking into account the equivalence of both derivations, we obtain a new analytical Fourier transform intregral involving incomplete gamma function. Energies of the generalized restrictive primitive model of electrolytes ($\eta$-RPM) and of the generalized one component plasma model ($\eta$-OCP) are given for the tridimensional, quasi-two dimensional and monolayers systems. Few numerical results, using Monte-Carlo simulations, for $\eta$-RPM and $\eta$-OCP monolayers systems are reported.Comment: to be published in Journal of Physics A: Mathematical and Theoretical (19 pages, 2 figures and 3 tables

L-arginine: A unique amino acid for improving depressed wound immune function following hemorrhage

Objective: To determine whether L-arginine has any salutary effects on wound immune cell function following trauma-hemorrhage. Background. Depressed wound immune function contributes to an increased incidence of wound infections following hemorrhage. Although administration of L-arginine has been shown to restore depressed cell-mediated immune responses following hemorrhage potentially by maintaining organ blood flow, it remains unknown whether Larginine has any salutary effects on the depressed local immune response at the wound site. Methods: Male mice were subjected to a midline laparotomy and polyvinyl sponges were implanted subcutaneously in the abdominal wound prior to hemorrhage (35 +/- 5 mm Hg for 90 min and resuscitation) or sham operation. During resuscitation mice received 300 mg/kg body weight L-arginine or saline (vehicle). Sponges were harvested 24 h thereafter, wound fluid collected and wound immune cells cultured for 24 h in the presence of LPS. Pro- (IL-1beta, IL-6) and anti-inflammatory (IL-10) cytokines were determined in the supernatants and the wound fluid. In addition, wounds were stained for IL-6 immunohistochemically. In a separate set of animals, skin and muscle blood flow was determined by microspheres. Results: The capacity of wound immune cells to release IL-1beta and IL-6 in vitro was significantly depressed in hemorrhaged mice receiving vehicle. Administration of L-arginine, however, improved wound immune cell function. In contrast, in vivo the increased IL-6 release at the wound site was decreased in L-arginine-treated mice following hemorrhage. Moreover, IL-10 levels were significantly increased in the wound fluid in hemorrhaged animals receiving L-arginine compared to vehicle-treated mice. In addition, the depressed skin and muscle blood flow after hemorrhage was restored by L-arginine. Conclusions: Thus, L-arginine might improve local wound cell function by decreasing the inflammatory response at the wound site. Since L-arginine protected wound immune cell function this amino acid might represent a novel and useful adjunct to fluid resuscitation for decreasing wound complications following hemorrhage. Copyright beta 2002 S. Karger AG, Basel

Formative evaluation of a mobile liquid portion size estimation interface for people with varying literacy skills

Chronically ill people, especially those with low literacy skills, often have difficulty estimating portion sizes of liquids to help them stay within their recommended fluid limits. There is a plethora of mobile applications that can help people monitor their nutritional intake but unfortunately these applications require the user to have high literacy and numeracy skills for portion size recording. In this paper, we present two studies in which the low- and the high-fidelity versions of a portion size estimation interface, designed using the cognitive strategies adults employ for portion size estimation during diet recall studies, was evaluated by a chronically ill population with varying literacy skills. The low fidelity interface was evaluated by ten patients who were all able to accurately estimate portion sizes of various liquids with the interface. Eighteen participants did an in situ evaluation of the high-fidelity version incorporated in a diet and fluid monitoring mobile application for 6 weeks. Although the accuracy of the estimation cannot be confirmed in the second study but the participants who actively interacted with the interface showed better health outcomes by the end of the study. Based on these findings, we provide recommendations for designing the next iteration of an accurate and low literacy- accessible liquid portion size estimation mobile interface

PREVALENCE OF TRICHOMONIASIS IN DOMESTIC AND WILD PIGEONS AND ITS EFFECTS ON HEMATOLOGICAL PARAMETERS

The present study was conducted to determine the prevalence of trichomoniasis and its effect on some blood parameters in pigeons. A total of 100 samples from the pigeons (50 wild and 50 domestic) were collected during the months of March and April 2005. Higher prevalence (P<0.05) was recorded in wild pigeons (60%) than in domestic pigeon (26%). The overall prevalence recorded was 43%, being non significantly higher in April (56%) than in March (30%). In infected pigeons, there was significant (P<0.05) decrease in hemoglobin concentration number of monocytes packed cell volume, body weight, than healthy birds. Likewise, the values of total leukocyte count, lymphocytes and eosinophils were higher significantly (P<0.05) in infected pigeons than the healthy ones. While, no significant difference was observed for heterophils count when infected and healthy birds were compared. It was concluded that trichomonad infection is quite common in wild, as well as in domestic, pigeons under the prevailing cage system

Drift compensation of gas sensor array data by Orthogonal Signal Correction

Drift is an important issue that impairs the reliability of gas sensing systems. Sensor aging, memory effects and environmental disturbances produce shifts in sensor responses that make initial statistical models for gas or odor recognition useless after a relatively short period (typically few weeks). Frequent recalibrations are needed to preserve system accuracy. However, when recalibrations involve numerous samples they become expensive and laborious. An interesting and lower cost alternative is drift counteraction by signal processing techniques. Orthogonal Signal Correction (OSC) is proposed for drift compensation in chemical sensor arrays. The performance of OSC is also compared with Component Correction (CC). A simple classification algorithm has been employed for assessing the performance of the algorithms on a dataset composed by measurements of three analytes using an array of seventeen conductive polymer gas sensors over a ten month period

Co-creating Understanding in Water Use and Agricultural Resilience in a Multi-scale Natural-human System: Sacramento River Valley-California's Water Heartland in Transition

The Sacramento River Valley (SRV), valued for its $2.5 billion agricultural production and its biodiversity, is the main supplier of California's water, servicing 25 million people. . Despite rapid changes to the region, little is known about the collective motivations and consequences of land and water use decisions, or the social and environmental vulnerability and resilience of the SRV. The overarching research goal is to examine whether the SRV can continue to supply clean water for California and accommodate agricultural production and biodiversity while coping with climate change and population growth. Without understanding these issues, the resources of the SRV face an uncertain future. The defining goal is to construct a framework that integrates cross-disciplinary and diverse stakeholder perspectives in order to develop a comprehensive understanding of how SRV stakeholders make land and water use decisions. Traditional approaches for modeling have failed to take into consideration multi-scale stakeholder input. Currently there is no effective method to facilitate producers and government agencies in developing a shared representation to address the issues that face the region. To address this gap, researchers and stakeholders are working together to collect and consolidate disconnected knowledge held by stakeholder groups (agencies, irrigation districts, and producers) into a holistic conceptual model of how stakeholders view and make decisions with land and water use under various management systems. Our approach integrates a top-down approach (agency stakeholders) for larger scale management decisions with a conceptual co-creation and data gathering bottom-up approach with local agricultural producer stakeholders for input water and landuse decisions. Land use change models that combine a top-down approach with a bottom-up stakeholder approach are rare and yet essential to understanding how the social process of land use change and ecosystem function are linked. Data gathered in a survey of agency stakeholder perspectives on how producers operate with respect to crop types, fallowing and water transfers, production components and land changes were compared with monitoring data (1990-2011) covering two drought emergency time periods in the state. Results show that a synthesis is required between top-down and bottom-up approaches to understand land-use dynamics, as decision makers had a limited understanding on water and land-use decisions by land owners at the farm level. A major goal is to create a high level of transparency and stakeholder buy-in by co-developing a model of the system. The approach captures context-based parcel level changes that include the range of variability in natural-human systems such as decisions stakeholders make during drought vs. non-drought years. These decisions are crucial to understanding the tensions that current and future land-use change dynamics will place on the vulnerable hydrological system of the SRV. Knowledge gained through this effort will provide a rigorous conceptual understanding of how the primary land and water stakeholders in the SRV obtain and use water to accommodate competing interests of local agricultural production and resilience, environmental management, and regional and state water needs

A systematic review of randomised controlled trials on the effectiveness of exercise programs on lumbo pelvic pain among postnatal women

Background: A substantial number of women tend to be affected by Lumbo Pelvic Pain (LPP) following child birth. Physical exercise is indicated as a beneficial method to relieve LPP, but individual studies appear to suggest mixed findings about its effectiveness. This systematic review aimed to synthesise evidence from randomised controlled trials on the effectiveness of exercise on LPP among postnatal women to inform policy, practice and future research. Methods: A systematic review was conducted of all randomised controlled trials published between January 1990 and July 2014, identified through a comprehensive search of following databases: PubMed, PEDro, Embase, Cinahl, Medline, SPORTDiscus, Cochrane Pregnancy and Childbirth Group’s Trials Register, and electronic libraries of authors’institutions. Randomised controlled trials were eligible for inclusion if the intervention comprised of postnatal exercise for women with LPP onset during pregnancy or within 3 months after delivery and the outcome measures included changes in LPP. Selected articles were assessed using the PEDro Scale for methodological quality and findings were synthesised narratively as meta-analysis was found to be inappropriate due to heterogeneity among included studies. Results: Four randomised controlled trials were included, involving 251 postnatal women. Three trials were rated as of ‘good’ methodological quality. All trials, except one, were at low risk of bias. The trials included physical exercise programs with varying components, differing modes of delivery, follow up times and outcome measures. Intervention in one trial, involving physical therapy with specific stabilising exercises, proved to be effective in reducing LPP intensity. An improvement in gluteal pain on the right side was reported in another trial and a significant difference in pain frequency in another. Conclusion: Our review indicates that only few randomised controlled trials have evaluated the effectiveness of exercise on LPP among postnatal women. There is also a great amount of variability across existing trials in the components of exercise programs, modes of delivery, follow up times and outcome measures. While there is some evidence to indicate the effectiveness of exercise for relieving LPP, further good quality trials are needed to ascertain the most effective elements of postnatal exercise programs suited for LPP treatment

When digital capital is not enough: reconsidering the digital lives of disabled university students.

publication-status: Publishedtypes: ArticleThe relationship that disabled university students have with both their technologies and institutions is poorly understood. This paper seeks to illuminate this relationship using the conceptual lens of digital capital. The results from a study that explored the technology experiences of 31 disabled students studying in one university were analysed with a view to revealing evidence for both cultural and social digital capital. The analysis suggests that disabled students possess significant levels of both cultural and social capital, but that there are times when this capital is compromised or insufficient to enable students to fully benefit from technologies. Possessing digital capital does not appear to guarantee complete inclusion into university life

Does spinal surgery for spinal tuberculosis during active infection predispose to post operative surgical site infection?: Experience From Kenyatta national hospital

Background: Spinal Tuberculosis (TB) is the most common form of skeletal TB. Its incidence has seen an increase over the past 3 decades due to the AIDS epidemic. Absolute non-operative treatment was offered in pre antibiotic era. Surgery has become an integral component in the management of spinal TB in current practice. The rate of SSI varies from 2% to 20% for all surgical spinal procedures.Objective: Does spinal surgery for spinal tuberculosis during active infection predispose to post operative Surgical Site Infection (SSI). The aim of this study was to note the incidence of infection in patients undergoing spinal surgery for tuberculosis.Methods: All patients who had complete medical records and had surgery for spinal tuberculosis were recruited into the study. The study period was from 2005 to 2015. Relevant data was collected and appropriately analyzed.Results: For all the patients, chemotherapy was started immediately after tuberculosis of the spine was diagnosed. Five patients had involvement of the lumbar region, one patient with involvement of the cervical region and the rest had involvement of the thoracic region. One patient had 3 vertebrae involved, 3 patients had one vertebrae involved and 14 patients had 2 vertebrae involved. Out of the 18 patients, 12 showed improvement after surgery, 4 patients had no difference after surgery and 2 patients worsened after surgery. Two patients showed improvement after 1 week; 3 patients after 2 weeks; 3 patients after 1 month; 4 patients after 2 months. Of the patients who worsened; 1 patient worsened by 1 grade while another worsened by 2 grades. No patient had any SSI. This was irrespective of whether they had instrumented spine surgery or not.Conclusion: This study shows that spinal surgery for spinal tuberculosis does not lead to increased surgical site infection even in the presence of active tuberculosis infection. Addition of spinal instrumentation to the surgical strategy does not predispose to increased infection rate. Larger studies need to be carried out to validate this data.Key words: Spinal tuberculosis, Spinal surgery, Surgical site infection