Construction and analysis of causally dynamic hybrid bond graphs

Engineering systems are frequently abstracted to models with discontinuous behaviour (such as a switch or contact), and a hybrid model is one which contains continuous and discontinuous behaviours. Bond graphs are an established physical modelling method, but there are several methods for constructing switched or ‘hybrid’ bond graphs, developed for either qualitative ‘structural’ analysis or efficient numerical simulation of engineering systems. This article proposes a general hybrid bond graph suitable for both. The controlled junction is adopted as an intuitive way of modelling a discontinuity in the model structure. This element gives rise to ‘dynamic causality’ that is facilitated by a new bond graph notation. From this model, the junction structure and state equations are derived and compared to those obtained by existing methods. The proposed model includes all possible modes of operation and can be represented by a single set of equations. The controlled junctions manifest as Boolean variables in the matrices of coefficients. The method is more compact and intuitive than existing methods and dispenses with the need to derive various modes of operation from a given reference representation. Hence, a method has been developed, which can reach common usage and form a platform for further study

Revisión de la literatura integradora acerca de intervenciones de la enfermería volcadas hacia el incremento del autocuidado entre pacientes con insuficiencia cardiaca

Objective: to analyze and summarize knowledge concerning critical components of interventions that have been proposed and implemented by nurses with the aim of optimizing self-care by heart failure patients.Methods: PubMed and CINAHL were the electronic databases used to search full peer-reviewed papers, presenting descriptions of nursing interventions directed to patients or to patients and their families and designed to optimize self-care. Forty-two studies were included in the final sample (n=4,799 patients).Results: this review pointed to a variety and complexity of nursing interventions. As self-care encompasses several behaviors, interventions targeted an average of 3.6 behaviors. Educational/counselling activities were combined or not with cognitive behavioral strategies, but only about half of the studies used a theoretical background to guide interventions. Clinical assessment and management were frequently associated with self-care interventions, which varied in number of sessions (1 to 30); length of follow-up (2 weeks to 12 months) and endpoints.Conclusions: these findings may be useful to inform nurses about further research in self-care interventions in order to propose the comparison of different modalities of intervention, the use of theoretical background and the establishment of endpoints to evaluate their effectiveness.Objetivo:analisar e sintetizar o conchecimento relacionado aos componentes críticos das intervençoes que têm, sido propostas e implementadas por enfermeiros(as) com objetivo de optimizar o auto-cuidado de pacientes portadores de insuficiência cardíaca.Método:PubMed e CINAHL foram as bases de dados electrônicas utilizadas para investigar artigos revisados por pares (peer review), apresentando as descrições das intervenções dirigidas ao paciente ou ao paciente e sua familia, visando melhorar o auto-cuidado. Foram incluídos 42 estudos na amostra final (n=4799 pacientes).Resultados:esta revisão apontou variedade e complexidade das intervenções de enfermagem. Como o auto-cuidado envolve diferentes comportamentos, as intervenções visaram em média 3,6 comportamentos. As Atividades de educação e aconselhamento foram combinadas ou não com estratégias cognitivo-comportamentais, mas somente a metade dos estudos utilizaram suporte teórico para guiar as intervenções. A avaliação e o manejo clínico foram frequentemente associados às intervenções de auto-cuidado, as quais variam em número de sessões (1 a 30), duração do seguimento (2 semanas a 12 meses) e desfechos.Conclusão:estes resultados podem ser úteis para guiar os enfermeiros no que se refere à futuros estudos sobre intervenções de auto-cuidado, de maneira a propor a comparação de diferentes modalidades de intervenção, uso de suporte teórico e estabelecimento de desfechos para melhor avaliar sua eficácia.Objetivo:analizar y sintetizar el conocimiento relacionado a componentes críticos de intervenciones que han sido propuestas e implementadas por enfermeros(as) con el objetivo de optimizar el autocuidado entre pacientes con insuficiencia cardiaca.Método:PUBMED y CINAHL han sido las bases de datos electrónicas usadas para investigar artículos revisados por pares (peer review), presentando descripciones de intervenciones destinadas a perfeccionar el autocuidado dirigido al paciente o al paciente y a su familia. Se incluyeron 42 estudios en la muestra final (n=4799 pacientes).Resultados:esta revisión apuntó a una variedad y complejidad de intervenciones de enfermería. Como el autocuidado abarca varios comportamientos, las intervenciones tuvieron como blanco, en media, 3,6 comportamientos. Actividades de educación/consejería fueron combinadas o no con estrategias cognitivo-comportamentales, pero tan solo cerca de la mitad de los estudios tenían aporte teórico para guiar intervenciones. La gestión y la evaluación clínica fueron frecuentemente asociadas a intervenciones de autocuidado, las cuales oscilaron en número de sesiones (1 a 30), duración del seguimiento (2 semanas a 12 meses) y objetivos.Conclusiones:estos resultados pueden ser útiles para informar a las enfermeras acerca de nuevas investigaciones en intervenciones de autocuidado, de modo a proponer la comparación de distintas modalidades de intervención, el uso de un aporte teórico y el establecimiento de objetivos para evaluar su eficacia

Long-term exposure to air pollution and hospital admissions for ischemic stroke. A register-based case-control study using modelled NOx as exposure proxy

Background: Long-term exposure to air pollution is a hypothesized risk factor for ischemic stroke. In a large case-control study with a complete study base, we investigated whether hospital admissions for ischemic stroke were associated with residential concentrations of outdoor NOx, as a proxy for exposure to air pollution, in the region of Scania, Southern Sweden. Methods: We used a two-phase case-control study design, including as first-phase controls all individuals born between 1923 and 1965 and residing in Scania in 2002 (N=556 912). We defined first-phase cases as first-time ischemic stroke patients residing in Scania and registered in the Swedish stroke register between 2001 and 2005 (N=4 904) and second-phase cases as cases for whom we had information on smoking status, diabetes, and medication for hypertension (N=4 375). For the controls, information on these covariables was collected from a public health survey, resulting in 4 716 second-phase controls. With a geographical information system and an emission database, individual residential outdoor annual mean NOx concentration was modelled. The data were analyzed with logistic regression. Results: We found no evident association between NOx and ischemic stroke. For example, the odds ratio for ischemic stroke associated with the NOx category 20-30 mu g/m(3) compared to the reference category of <10 mu g/m(3) was 0.95 (95% CI 0.86-1.06). Conclusion: In this study area, with generally low levels of air pollution, using a complete study base, high-quality ascertainment of cases, and individually modelled exposure, we did not observe any clear association between NOx and ischemic stroke hospital admissions

New fluorescent perylene bisimide indicators—a platform for broadband pH optodes

Asymmetric perylene bisimide (PBI) dyes are prepared and are shown to be suitable for the preparation of fluorescence chemosensors for pH. They carry one amino-functional substituent which introduces pH sensitivity via photoinduced electron transfer (PET) while the other one increases solubility. The luminescence quantum yields for the new indicators exceed 75% in the protonated form. The new indicators are non-covalently entrapped in polyurethane hydrogel D4 and poly(hydroxyalkylmethacrylates). Several PET functions including aliphatic and aromatic amino groups were successfully used to tune the dynamic range of the sensor. Because of their virtually identical spectral properties, various PBIs with selected PET functions can easily be integrated into a single sensor with enlarged dynamic range (over 4 pH units). PBIs with two different substitution patterns in the bay position are investigated and possess variable spectral properties. Compared with their tetrachloro analogues, tetra-tert-butyl-substituted PBIs yield more long-wave excitable sensors which feature excellent photostability. Cross-sensitivity to ionic strength was found to be negligible. The practical applicability of the sensors may be compromised by the long response times (especially in case of tetra-tert-butyl-substituted PBIs)

Abrasive, Silica Phytoliths and the Evolution of Thick Molar Enamel in Primates, with Implications for the Diet of Paranthropus boisei

Background: Primates—including fossil species of apes and hominins—show variation in their degree of molar enamel thickness, a trait long thought to reflect a diet of hard or tough foods. The early hominins demonstrated molar enamel thickness of moderate to extreme degrees, which suggested to most researchers that they ate hard foods obtained on or near the ground, such as nuts, seeds, tubers, and roots. We propose an alternative hypothesis—that the amount of phytoliths in foods correlates with the evolution of thick molar enamel in primates, although this effect is constrained by a species ’ degree of folivory. Methodology/Principal Findings: From a combination of dietary data and evidence for the levels of phytoliths in plant families in the literature, we calculated the percentage of plant foods rich in phytoliths in the diets of twelve extant primates with wide variation in their molar enamel thickness. Additional dietary data from the literature provided the percentage of each primate’s diet made up of plants and of leaves. A statistical analysis of these variables showed that the amount of abrasive silica phytoliths in the diets of our sample primates correlated positively with the thickness of their molar enamel, constrained by the amount of leaves in their diet (R 2 = 0.875; p,.0006). Conclusions/Significance: The need to resist abrasion from phytoliths appears to be a key selective force behind the evolution of thick molar enamel in primates. The extreme molar enamel thickness of the teeth of the East African homini

Increased Level of Myeloid-Derived Suppressor Cells, Programmed Death Receptor Ligand 1/Programmed Death Receptor 1, and Soluble CD25 in Sokal High Risk Chronic Myeloid Leukemia

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