Stabilizing Nonstationary Electrochemical Time Series

Electrochemical systems are ideal working-horses for studying oscillatory dynamics. Experimentally obtained time series, however, are usually associated with a spontaneous drift in some uncontrollable parameter that triggers transitions among different oscillatory patterns, despite the fact that all controllable parameters are kept constant. Herein we present an empirical method to stabilize experimental potential time series. The method consists of applying a negative galvanodynamic sweep to compensate the spontaneous drift and was tested for the oscillatory electro-oxidation of methanol on platinum. For a wide range of applied currents, the base system presents spontaneous transitions from quasi-harmonic to mixed mode oscillations. Temporal patterns were stabilized by galvanodynamic sweeps at different rates. The procedure resulted in a considerable increase in the number of oscillatory cycles from 5 to 20 times, depending on the specific temporal pattern. The spontaneous drift has been associated with uncompensated oscillations, in which the coverage of some adsorbed species are not reestablished after one cycle; i.e., there is a net accumulation and/or depletion of adsorbed species during oscillations. We interpreted the rate of the galvanodynamic sweep in terms of the time scales of the poisoning processes that underlies the uncompensated oscillations and thus the spontaneous slow drift.

Effects of chronic acetazolamide administration on gas exchange and acid-base control in pulmonary circulation in exercising horses

P>Reasons for performing study:Carbonic anhydrase (CA) catalyses the hydration/dehydration reaction of CO(2) and increases the rate of Cl- and HCO(3)- exchange between the erythrocytes and plasma. Therefore, chronic inhibition of CA has a potential to attenuate CO(2) output and induce greater metabolic and respiratory acidosis in exercising horses.Objectives:To determine the effects of Carbonic anhydrase inhibition on CO(2) output and ionic exchange between erythrocytes and plasma and their influence on acid-base balance in the pulmonary circulation (across the lung) in exercising horses with and without CA inhibition.Methods:Six horses were exercised to exhaustion on a treadmill without (Con) and with CA inhibition (AczTr). CA inhibition was achieved with administration of acetazolamide (10 mg/kg bwt t.i.d. for 3 days and 30 mg/kg bwt before exercise). Arterial, mixed venous blood and CO(2) output were sampled at rest and during exercise. An integrated physicochemical systems approach was used to describe acid base changes.Results:AczTr decreased the duration of exercise by 45% (P < 0.0001). During the transition from rest to exercise CO(2) output was lower in AczTr (P < 0.0001). Arterial PCO(2) (P < 0.0001; mean +/- s.e. 71 +/- 2 mmHg AczTr, 46 +/- 2 mmHg Con) was higher, whereas hydrogen ion (P = 0.01; 12.8 +/- 0.6 nEq/l AczTr, 15.5 +/- 0.6 nEq/l Con) and bicarbonate (P = 0.007; 5.5 +/- 0.7 mEq/l AczTr, 10.1 +/- 1.3 mEq/l Con) differences across the lung were lower in AczTr compared to Con. No difference was observed in weak electrolytes across the lung. Strong ion difference across the lung was lower in AczTr (P = 0.0003; 4.9 +/- 0.8 mEq AczTr, 7.5 +/- 1.2 mEq Con), which was affected by strong ion changes across the lung with exception of lactate.Conclusions:CO(2) and chloride changes in erythrocytes across the lung seem to be the major contributors to acid-base and ions balance in pulmonary circulation in exercising horses.

An examination of constraints affecting the intralimb coordination of hemiparetic gait

A dynamical systems approach to the study of locomotor intralimb coordination in those with hemiparesis led to an examination of the utility of the shank-thigh relative phase (RP) as a collective variable and the identification of potential constraints that may shape this coordination. Eighteen non-disabled individuals formed three groups matched to the age and gender of six participants with chronic right hemiparesis. The three groups differed in the constraints imposed on their walking: (1) walking at their preferred walking speed; (2) walking as slowly as those with hemiparesis; and, (3) walking slowly with a right ankle-foot orthosis (AFO). The results revealed an asymmetry in intralimb coordination between the unaffected and affected leg of those with hemiparesis localized to the latter third of the gait cycle when the limb is advanced from the end of stance to the reestablishment of a new stance. Walking slowly with or without an AFO resulted in no measureable effect in the non-disabled, but accounts for 22% of the variance in the intralimb coordination of the hemiplegic's affected limb and 16% in the unaffected limb. The AFO offered little additional contribution. These results derive from shank-thigh RP that is shown to provide more information about intralimb coordination than knee angle displacement. Implications for these results and the use of RP for rehabilitation are discussed. (C) 2000 Elsevier B.V. B.V. All rights reserved. PsycINFO classification. 3297. 2330.

Inovações tecnológicas e a complexidade do sistema econômico

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Análise geomorfológica e de impactos ambientais da microbacia do Córrego Wenzel - Rio Claro/SP

This study aimed to survey and analyze the geomorphological aspects of watershed stream Wenzel in Rio Claro, as well as anthropogenic incidents about which he eventually causing serious environmental impacts. All these changes in the natural environment are generated from the constant development of the urban environment, which ends up leaving aside factors relevant to the natural order and that over time they become problems to humans. As various forms of environmental degradation occurring on some form of relief, geomorphology can make a major contribution in this field, since the analysis of the hydrographic network can lead to understanding and explanation of numerous geomorphological issues because the waterways are process morphogenetic the most active in the terrestrial landscape sculpture. The research with a systems approach and vision interrelated aspects in question may even serve as a basis for practical planning and urban management, in addition to detailed study of the area, which is of paramount importance to the local society

Psychosocial correlates of rehabilitation from stroke: a longitudinal study

The general aim of this dissertation was to uncover the association between psychosocial factors and rehabilitation outcome after stroke. METHOD. A sample of patients with stroke (n=40) and their caregivers (n=36) were assessed at admission to and six months after discharge from rehabilitation hospital, using the following instruments: Structured Clinical Interview for DSM-IV, structured interview based on Diagnostic Criteria for Psychosomatic Research, Symptom Questionnaire, Psychosocial Index, Psychological Well-Being Scales, and Family Assessment Device. 40 subjects from the general population underwent the same psychological assessment. In addition, patients' functional status was measured using the Functional Independence Measure. RESULTS. Stroke survivors reported lower education and higher alcohol consumption than controls. No significant differences emerged between the two groups in the prevalence of psychiatric diagnoses or psychosomatic syndromes, however patients reported significantly higher levels of anxiety, depression, somatic symptoms, and lower autonomy than controls. Caregivers reported significantly higher scores in anxiety, depression, and somatic symptoms compared to normative data, while no impairments emerged in psychological well-being and family functioning. At six-month follow-up, in patients a significant decrease in smoking habit and an increase in DSM diagnoses were reported. Both stroke survivors and caregivers showed significant reductions in anxiety, with patients displaying also a decrease in somatic symptoms, an increase in stress and a deterioration in quality of life. Significant deteriorations in several aspects of family functioning was perceived only by patients. An association between patients' functional recovery in the cognitive domain and family behavior control emerged. For caregivers, family functioning significantly predicted hostility and somatic symptoms were associated with family affective involvement. CONCLUSIONS. These data highlight the utility in the Italian setting of the adoption of a psychosocial assessment and a family-systems approach in stroke rehabilitation, in order to development interventions properly targeted to the characteristics of patients and their family members.

Invariant barriers to reactive front propagation in fluid flows

We present theory and experiments on the dynamics of reaction fronts in two-dimensional, vortex-dominated flows, for both time-independent and periodically driven cases. We find that the front propagation process is controlled by one-sided barriers that are either fixed in the laboratory frame (time-independent flows) or oscillate periodically (periodically driven flows). We call these barriers burning invariant manifolds (BIMs), since their role in front propagation is analogous to that of invariant manifolds in the transport and mixing of passive impurities under advection. Theoretically, the BIMs emerge from a dynamical systems approach when the advection-reaction-diffusion dynamics is recast as an ODE for front element dynamics. Experimentally, we measure the location of BIMs for several laboratory flows and confirm their role as barriers to front propagation.

The Impact of Family Stressors on the Social Development of Adolescents Admitted to a Residential Treatment Facility

The focus of this research was to determine the impact of family stressors on the social development of adolescents at admission to long-term mental health residential care. The study was conducted at the Waco Center for Youth, the only long-term residential care agency serving emotionally and behaviorally challenged adolescents and their families that functions under the authority of the Texas Department of State Health Services. Data was obtained from social assessment forms (N=457) in case records of clients. The prevalence of problem behaviors exhibited by the youth upon entry to the residential facility was examined and it was found that the youth entering the facility were experiencing severe impairment in their social development across several domains. Results indicated that youth with more family stressors exhibited significantly greater impairment in their social development (b = .19, p = .000) which suggests that the combination of multiple stressors within a family inhibits adolescent social development. The research supports a family systems approach to treatment that focuses on building family strengths and actively involving family in the intervention process.

Barry Saltzman and the Theory of Climate

Barry Saltzman was a giant in the fields of meteorology and climate science. A leading figure in the study of weather and climate for over 40 yr, he has frequently been referred to as the "father of modern climate theory." Ahead of his time in many ways, Saltzman made significant contributions to our understanding of the general circulation and spectral energetics budget of the atmosphere, as well as climate change across a wide spectrum of time scales. In his endeavor to develop a unified theory of how the climate system works, lie played a role in the development of energy balance models, statistical dynamical models, and paleoclimate dynamical models. He was a pioneer in developing meteorologically motivated dynamical systems, including the progenitor of Lorenz's famous chaos model. In applying his own dynamical-systems approach to long-term climate change, he recognized the potential for using atmospheric general circulation models in a complimentary way. In 1998, he was awarded the Carl-Gustaf Rossby medal, the highest honor of the American Meteorological Society "for his life-long contributions to the study of the global circulation and the evolution of the earth's climate." In this paper, the authors summarize and place into perspective some of the most significant contributions that Barry Saltzman made during his long and distinguished career. This short review also serves as an introduction to the papers in this special issue of the Journal of Climate dedicated to Barry's memory.

A new measure for party coherence: Applying a physics-based concept to the Swiss party system

The paper revives a theoretical definition of party coherence as being composed of two basic elements, cohesion and factionalism, to propose and apply a novel empirical measure based on spin physics. The simultaneous analysis of both components using a single measurement concept is applied to data representing the political beliefs of candidates in the Swiss general elections of 2003 and 2007, proposing a connection between the coherence of the beliefs party members hold and the assessment of parties being at risk of splitting. We also compare our measure with established polarization measures and demonstrate its advantage with respect to multi-dimensional data that lack clear structure. Furthermore, we outline how our analysis supports the distinction between bottom-up and top-down mechanisms of party splitting. In this way, we are able to turn the intuition of coherence into a defined quantitative concept that, additionally, offers a methodological basis for comparative research of party coherence. Our work serves as an example of how a complex systems approach allows to get a new perspective on a long-standing issue in political science.

Na+ channel function, regulation, structure, trafficking and sequestration.

This paper is the second of a series of three reviews published in this issue resulting from the University of California Davis Cardiovascular Symposium 2014: Systems approach to understanding cardiac excitation-contraction coupling and arrhythmias: Na(+) channel and Na(+) transport. The goal of the symposium was to bring together experts in the field to discuss points of consensus and controversy on the topic of sodium in the heart. The present review focuses on Na(+) channel function and regulation, Na(+) channel structure and function, and Na(+) channel trafficking, sequestration and complexing.

Can accreditation work as a tool for quality improvement in public health? A critical review

Public health departments play an important role in promoting and preserving the health of communities. The lack of a system to ensure their quality and accountability led to the development of a national voluntary accreditation program by Public Health Accreditation Board (PHAB). The concept that accreditation will lead to quality improvement in public health which will ultimately lead to healthy communities seems intuitive but lacks a robust body of evidence. A critical review of literature was conducted to explore if accreditation can lead to quality improvement in public health. The articles were selected from publically available databases using a specific set of criteria for inclusion, exclusion, and appraisal. To understand the relationship between accreditation and quality improvement, the potential strengths and limitations of accreditation process were evaluated. Recommendations for best practices are suggested so that public health accreditation can yield maximum benefits. A logic model framework to help depict the impact of accreditation on various levels of public health outcomes is also discussed in this thesis. The literature review shows that existing accreditation programs in other industries show limited but encouraging evidence that accreditation will improve quality and strengthen the delivery of public health services. While progress in introducing accreditation in public health can be informed by other accredited industries, the public health field has its own set of challenges. Providing incentives, creating financing strategies, and having a strong leadership will allow greater access to accreditation by all public health departments. The suggested recommendations include that continuous evaluation, public participation, systems approach, clear vision, and dynamic standards should become hallmarks of the accreditation process. Understanding the link between accreditation, quality improvement, and health outcomes will influence the successful adoption and implementation of the public health accreditation program. This review of literature suggests that accreditation is an important step in improving the quality of public health departments and in ultimately improving the health of communities. However, accreditation should be considered in an integrated system of tools and approaches to improve the public health practice. Hence, it is a means to an end - not an end unto itself.^

STRATEGIES FOR THE TRANSFER OF APPROPRIATE TECHNOLOGY TO DEVELOPING COUNTRIES: THE IMPLEMENTATION AND DEVELOPMENT OF ENVIRONMENTAL HEALTH PROGRAMS IN TUNISIA

This dissertation focuses on Project HOPE, an American medical aid agency, and its work in Tunisia. More specifically this is a study of the implementation strategies of those HOPE sponsored projects and programs designed to solve the problems of high morbidity and infant mortality rates due to environmentally related diarrheal and enteric diseases. Several environmental health programs and projects developed in cooperation with Tunisian counterparts are described and analyzed. These include (1) a paramedical manpower training program; (2) a national hospital sanitation and infection control program; (3) a community sewage disposal project; (4) a well reconstruction project; and (5) a solid-waste disposal project for a hospital.^ After independence, Tunisia, like many developing countries, encountered several difficulties which hindered progress toward solving basic environmental health problems and prompted a request for aid. This study discusses the need for all who work in development programs to recognize and assess those difficulties or constraints which affect the program planning process, including those latent cultural and political constraints which not only exist within the host country but within the aid agency as well. For example, failure to recognize cultural differences may adversely affect the attitudes of the host staff towards their work and towards the aid agency and its task. These factors, therefore, play a significant role in influencing program development decisions and must be taken into account in order to maximize the probability of successful outcomes.^ In 1969 Project HOPE was asked by the Tunisian government to assist the Ministry of Health in solving its health manpower problems. HOPE responded with several programs, one of which concerned the training of public health nurses, sanitary technicians, and aids at Tunisia's school of public health in Nabeul. The outcome of that program as well as the strategies used in its development are analyzed. Also, certain questions are addressed such as, what should the indicators of success be, and when is the time right to phase out?^ Another HOPE program analyzed involved hospital sanitation and infection control. Certain generic aspects of basic hospital sanitation procedures were documented and presented in the form of a process model which was later used as a "microplan" in setting up similar programs in other Tunisian hospitals. In this study the details of the "microplan" are discussed. The development of a nation-wide program without any further need of external assistance illustrated the success of HOPE's implementation strategies.^ Finally, although it is known that the high incidence of enteric disease in developing countries is due to poor environmental sanitation and poor hygiene practices, efforts by aid agencies to correct these conditions have often resulted in failure. Project HOPE's strategy was to maximize limited resources by using a systems approach to program development and by becoming actively involved in the design and implementation of environmental health projects utilizing "appropriate" technology. Three innovative projects and their implementation strategies (including technical specifications) are described.^ It is advocated that if aid agencies are to make any progress in helping developing countries basic sanitation problems, they must take an interdisciplinary approach to progrm development and play an active role in helping counterparts seek and identify appropriate technologies which are socially and economically acceptable. ^

Engaging stakeholders in community-level obesity prevention programming: Evaluation of the Fit Family Challenge

Introduction: Both a systems approach to change and a focus on multi-sector interventions ensures obesity prevention programming within the community is equitable, sustainable, and cost-effective. An authentic community engagement approach is required to implement interventions guided by best-evidence research and practice. Although there are examples illustrating the benefits of community engagement, there is no standardized method to implement it. The San Antonio Sports Foundation (SA Sports), a non-profit community-based organization, implements a variety of free events and programs promoting active life styles. One such program is the Fit Family Challenge which is a summer-long program implemented at the school level targeted at families. ^ Aims: This thesis was a culmination of the experience from the student collaborating with SA Sports as part of a practicum opportunity. Using secondary data collected by the Fit Family Challenge during the 2011 year, the goals of this thesis were: to assess individual changes; evaluate short-term impact; and describe the community engagement process. ^ Methods: SA Sports collected quantitative and qualitative data during the implementation and evaluation of the FFC program. SA Sports allowed the used of de-identified data to be analyzed to study the aims of this thesis. ^ Results: The program was able to provide families with the knowledge, information, and opportunity to exercise as a family and cook healthier meals. School district coordinators were generally satisfied and illustrated the benefits of a community partnership. An authentic community engagement was present highlighting the importance of communication, collaboration and the sustainability of such partnerships in the community. ^ Conclusion: The success of an obesity program should focus on triggers that initiate behavioral change rather than physiological changes. The evaluation was guided by a community engagement approach, which illustrated the development of new partnerships and the strengthening of other collaborations. Ultimately, the engagement approach empowered the community to identify their own problems and build collaboration, rather than tackling obesity prevention alone. ^