Critical fluctuations of noisy period-doubling maps

We extend the theory of quasipotentials in dynamical systems by calculating, within a broad class of period-doubling maps, an exact potential for the critical fluctuations of pitchfork bifurcations in the weak noise limit. These far-from-equilibrium fluctuations are described by finite-size mean field theory, placing their static properties in the same universality class as the Ising model on a complete graph. We demonstrate that the effective system size of noisy period-doubling bifurcations exhibits universal scaling behavior along period-doubling routes to chaos.Comment: 11 pages, 5 figure

Investigation of the role of endosomal Toll-like receptors in murine collagen-induced arthritis reveals a potential role for TLR7 in disease maintenance

INTRODUCTION Endosomal toll-like receptors (TLRs) have recently emerged as potential contributors to the inflammation observed in human and rodent models of rheumatoid arthritis (RA). This study aims to evaluate the role of endosomal TLRs and in particular TLR7 in the murine collagen induced arthritis (CIA) model. METHODS CIA was induced by injection of collagen in complete Freund's adjuvant. To investigate the effect of endosomal TLRs in the CIA model, mianserin was administered daily from the day of disease onset. The specific role of TLR7 was examined by inducing CIA in TLR7-deficient mice. Disease progression was assessed by measuring clinical score, paw swelling, serum anti-collagen antibodies histological parameters, cytokine production and the percentage of T regulatory (Treg) cells. RESULTS Therapeutic administration of mianserin to arthritic animals demonstrated a highly protective effect on paw swelling and joint destruction. TLR7-/- mice developed a mild arthritis, where the clinical score and paw swelling were significantly compromised in comparison to the control group. The amelioration of arthritis by mianserin and TLR7 deficiency both corresponded with a reduction in IL-17 responses, histological and clinical scores, and paw swelling. CONCLUSIONS These data highlight the potential role for endosomal TLRs in the maintenance of inflammation in RA and support the concept of a role for TLR7 in experimental arthritis models. This study also illustrates the potential benefit that may be afforded by therapeutically inhibiting the endosomal TLRs in RA

Development of a weighted leanness measurement method in modular construction companies

This paper outlines the development of an improved approach to the use of lean tools and techniques to improve the performance of manufacturing enterprises. Several research studies attempt to measure the overall leanness score of the manufacturing process; however, they failed to consider the interdependent relationships between lean performance metrics and considered all performance measures to be equally important during analysis. This paper proposes the weighted leanness assessment methodology to further extend the most recent developed leanness assessment model. The developed methodology in this research provides an integrated leanness score of the production process which considers the interrelationships between different performance metrics due to competing for business and operational strategies. The fuzzy-based analytic network process approach is used to measure and allocate relative importance weightings to each performance metric. The result from the proposed methodology in this research provides a more accurate overall leanness score by prioritising different performance measures according to the manufacturer’s needs. A case study was conducted to illustrate the effectiveness and validity of the proposed model and methodologies

Louons le courage des petits paysans

L’agriculture est une activité à risques, et même à hauts risques. Contrairement à la plupart des autres activités de production, elle est tributaire de facteurs naturels qui échappent totalement au contrôle. L’expérience montre que, sur une période plus ou moins longue, les agriculteurs sont souvent confrontés à plusieurs problèmes graves. Ceux qui pratiquent la riziculture pluviale dans les basses terres du Nigeria peuvent souffrir la même année de sécheresse et d’inondation, ce qui entraîne une perte de 80 % à 100 % de leur récolte. Mais il y a aussi les maladies et les ravageurs : dans le Nigeria oriental, une attaque de mouche des galles du riz a ainsi détruit 80 % des récoltes en 1988. Des problèmes en tous genres Parmi les autres problèmes récurrents, mentionnons la destruction des récoltes par le bétail des Peuhls, fréquente dans le nord du Nigeria. Les troubles survenus alors que les agriculteurs défendaient leurs cultures contre des éleveurs Peuhls armés ont coûté la vie à nombre d’entre eux. Il y a aussi les feux de brousse, qui ne sont pas toujours bien contrôlés, et peuvent détruire les cultures comme les récoltes stockées. Comment font les petits paysans du Nigeria, autrement dit 70 % de la population active du pays, pour subir tous ces événements et rester tout de même mariés à leur terre ' pour le meilleur et pour le pire ' ? J’ai observé avec beaucoup d’intérêt des hommes puissants — des militaires à la retraite, par exemple, ou des chefs de village riches et influents. Je les ai vus plier bagage après deux ou trois ans seulement d’activité agricole. Ils avaient amené de lourdes machines pour défricher et cultiver, et les résultats ? Il n’est même pas besoin de quitter les routes pour voir les ravages de l’érosion sur leurs terres. Des carcasses de hangars et de silos sont abandonnées dans la brousse, à tel point qu’on se demande s’ils n’ont pas été construits pour des animaux sauvages qui seraient alors plus favorisés par le Ciel que leurs homologues domestiques ! À un moment, il y a eu une prolifération de ce genre d’agriculteurs au Nigeria. Pensaient-ils qu’il suffisait de semer de l’argent pour récolter des millions ? Ils ont été bien déçus ! Ils avaient seulement oublié que par essence l’agriculture exige de travailler dur, de prendre des risques, de s’engager totalement, avec détermination. Une ténacité admirable Les petits paysans, eux, sont attachés à leur terre, qu’il pleuve ou qu’il vente. Jamais nous ne louerons assez leur courage face à leurs si nombreux problèmes ! Ce n’est pas le manque de pluie qui les découragera de cultiver l’année suivante. À ces moments-là, ils parlent des faiseurs de pluie, des gens qui prient pour faire venir les pluies quand celles-ci sont en retard. Dans certaines régions du Nord, les plants de riz sont cultivés en pépinières environ un mois avant les pluies. Il faut pendant ce temps apporter l’eau de cours lointains et de mares qui s’assèchent un peu plus chaque jour. Les paysans cultivent aussi des plantes à cycle court, comme le mil et le niébé. Quand on voit la variété de ce qu’on trouve sur le marché, et que l’on réalise que tout cela est produit par les paysans, leurs mains, leurs houes et leurs machettes, on ne peut qu’être admiratif. Ce sont eux aussi qui savent changer de vitesse quand il ne leur suffit plus de produire pour consommer et qu’ils envisagent d’envoyer leurs enfants faire des études, bien que ce soit au Nigeria plus difficile que jamais. Ils voudraient aussi des véhicules motorisés pour transporter leur récolte, à la maison, puis au marché, mais cela aussi suppose d’en avoir les moyens. L’électricité installée par le gouvernement actuel leur apporte un nouveau confort. Ils vont bientôt vouloir acheter des équipements domestiques, des télévisions et des magnétoscopes. Ces nouveaux appétits vont nourrir leurs ambitions, mais celles-ci seront freinées par la parcellisation de leurs terres, du fait du système foncier : encore un défi ! Tous ces petits paysans méritent nos félicitations pour la part immense qu’ils prennent à la production alimentaire mondiale. Ils seraient mieux épaulés si les infrastructures qui leur sont nécessaire étaient mieux adaptées, si les intrants étaient subventionnés… Mais au bout du compte, leur avenir est dans leurs mains et dépend aussi de facteurs que personne ne contrôle ! Les opinions exprimées dans ce Point de vue sont celles de l’auteur, et ne reflètent pas nécessairement les idées du CTA. [caption] Andrew Saba Gana est sélectionneur dans le programme de recherche sur le riz du National Cereals Research Institute au Nigeria. Son activité le met en contact avec les paysans des différentes zones agro-écologiques de son pays.L’agriculture est une activité à risques, et même à hauts risques. Contrairement à la plupart des autres activités de production, elle est tributaire de facteurs naturels qui échappent totalement au contrôle.L’expérience montre que, sur..

Markovian approach for the analysis and prediction of weekly rainfall pattern in Makurdi, Benue State, Nigeria

A stochastic model to study weekly rainfall pattern has been presented in this paper. The Markovian method was used to predict and analyze weekly rainfall pattern of Makurdi, Benue state, Nigeria for a period of eleven years (2005-2015). After some successful iterations of the model, its stabilizes to equilibrium probabilities, revealing that in the long-run 22% of the weeks during rainy season in Makurdi, will experience no rainfall , 50% will experience low rainfall, 25% will experience moderate rainfall and 2% will experience high rainfall. The model also reveals that, a week of high rainfall cannot be followed by another week of high rainfall , a week of high rainfall cannot be followed by a week of no rainfall, and a week of moderate rainfall cannot precede a week of high rainfall. These results are important information to the residents of Markudi and environmental management scientists to plan for the uncertainty of rainfall.Keywords: Markov chain, Weekly Rainfall, Transition Probabilities, Equilibrium probabilities Probability State Vector, Makurdi

Wearable Near Infrared Spectroscopy for Noninvasive Assessment of Cerebral Oxygenation in Pediatric Sickle Cell Disease

About 1 out of every 13 African American infants are born with the Sickle Cell Trait. Sickle Cell Disease (SCD) has a profound effect on the brain due to chronic anemia and abnormal perfusion. Indeed, the risk of stroke is 300 times higher than the general population. Assessment of cerebral oxygenation in SCD is important to screen the risk of stroke and monitoring of therapeutic effects. To address this need, the technical solution that we propose is a photonic device using functional Near Infrared Spectroscopy (fNIRS) that noninvasively measures oxyhemoglobin (oxy-Hb) and deoxyhemoglobin (deoxy-Hb) levels in the bloodstream. We have built our prototype fNIRS device that consists of an ESP-32 microcontroller with a built-in Digital to Analog and Analog to Digital converter channels (DAC and ADC), three Operational Amplifiers (two AD8655 and one OPA363), two LEDs for emitting light into the skin tissue, and a Photodiode for measuring the remitted light intensity. Oxy-Hb has a higher absorption rate at lower wavelengths, while deoxy-Hb has a higher absorption rate at higher wavelengths. Thus, we use 650 nm and 950nm wavelengths to accurately measure oxy-Hb and deoxy-Hb. Using the Beer-Lambert law, we can determine the changes in oxygenation between the two. We are currently conducting performance tests on a set of optical phantoms mimicking biological tissue optical properties. This bench-top verification demonstrates that our prototype can noninvasively track the changes of tissue oxygenation level and will be ready for further validation on human subjects in the future

A Social-Ecological-Infrastructural Systems Framework for Interdisciplinary Study of Sustainable City Systems

Cities are embedded within larger-scale engineered infrastructures (e.g., electric power, water supply, and transportation networks) that convey natural resources over large distances for use by people in cities. The sustainability of city systems therefore depends upon complex, cross-scale interactions between the natural system, the transboundary engineered infrastructures, and the multiple social actors and institutions that govern these infrastructures. These elements, we argue, are best studied in an integrated manner using a novel social-ecological-infrastructural systems (SEIS) framework. In the biophysical subsystem, the SEIS framework integrates urban metabolism with life cycle assessment to articulate transboundary infrastructure supply chain water, energy, and greenhouse gas (GHG) emission footprints of cities. These infrastructure footprints make visible multiple resources (water, energy, materials) used directly or indirectly (embodied) to support human activities in cities. They inform cross-scale and cross-infrastructure sector strategies for mitigating environmental pollution, public health risks and supply chain risks posed to cities. In the social subsystem, multiple theories drawn from the social sciences explore interactions between three actor categories—individual resource users, infrastructure designers and operators, and policy actors—who interact with each other and with infrastructures to shape cities toward sustainability outcomes. Linking of the two subsystems occurs by integrating concepts, theories, laws, and models across environmental sciences/climatology, infrastructure engineering, industrial ecology, architecture, urban planning, behavioral sciences, public health, and public affairs. Such integration identifies high-impact leverage points in the urban SEIS. An interdisciplinary SEIS-based curriculum on sustainable cities is described and evaluated for its efficacy in promoting systems thinking and interdisciplinary vocabulary development, both of which are measures of effective frameworks

Ultrasound IMT measurement on a multi-ethnic and multi-institutional database: Our review and experience using four fully automated and one semi-automated methods

Automated and high performance carotid intima-media thickness (IMT) measurement is gaining increasing importance in clinical practice to assess the cardiovascular risk of patients. In this paper, we compare four fully automated IMT measurement techniques (CALEX, CAMES, CARES and CAUDLES) and one semi-automated technique (FOAM). We present our experience using these algorithms, whose lumen-intima and media-adventitia border estimation use different methods that can be: (a) edge-based; (b) training-based; (c) feature-based; or (d) directional Edge-Flow based. Our database (DB) consisted of 665 images that represented a multi-ethnic group and was acquired using four OEM scanners. The performance evaluation protocol adopted error measures, reproducibility measures, and Figure of Merit (FoM). FOAM showed the best performance, with an IMT bias equal to 0.025 ± 0.225 mm, and a FoM equal to 96.6%. Among the four automated methods, CARES showed the best results with a bias of 0.032 ± 0.279 mm, and a FoM to 95.6%, which was statistically comparable to that of FOAM performance in terms of accuracy and reproducibility. This is the first time that completely automated and user-driven techniques have been compared on a multi-ethnic dataset, acquired using multiple original equipment manufacturer (OEM) machines with different gain settings, representing normal and pathologic case

A Multi-Objective Methodology for Selecting Lean Initiatives in Modular Construction Companies

The implementation of lean manufacturing initiatives has produced significant impacts in improving operational performance and reducing manufacturing wastes in the production process. However, selecting an appropriate set of lean strategies is critical to avoid misapplication of the lean manufacturing techniques and consequential increase in non-value-adding activities. To the author’s best knowledge, there is currently no methodology to select lean strategies that considers their impacts on manufacturing wastes and performance metrics simultaneously. In this research, a multi-objective methodology is proposed that suggests an appropriate set of lean initiatives based on their impacts on performance metrics and manufacturing wastes and within manufacturers’ resource limitation. The proposed methodology in this research suggests the best set of lean initiatives for implementation that have highest impacts on identified critical performance metrics and manufacturing wastes. Therefore, manufacturers can assure that implementing suggested lean tools improves their production performance and reduces manufacturing wastes at the same time. A case study was conducted to show the effectiveness and validate the proposed model and methodologies