913 resultados para Bergeron line model


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Software Product Line Engineering has significant advantages in family-based software development. The common and variable structure for all products of a family is defined through a Product-Line Architecture (PLA) that consists of a common set of reusable components and connectors which can be configured to build the different products. The design of PLA requires solutions for capturing such configuration (variability). The Flexible-PLA Model is a solution that supports the specification of external variability of the PLA configuration, as well as internal variability of components. However, a complete support for product-line development requires translating architecture specifications into code. This complex task needs automation to avoid human error. Since Model-Driven Development allows automatic code generation from models, this paper presents a solution to automatically generate AspectJ code from Flexible-PLA models previously configured to derive specific products. This solution is supported by a modeling framework and validated in a software factory.

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Maximizing energy autonomy is a consistent challenge when deploying mobile robots in ionizing radiation or other hazardous environments. Having a reliable robot system is essential for successful execution of missions and to avoid manual recovery of the robots in environments that are harmful to human beings. For deployment of robots missions at short notice, the ability to know beforehand the energy required for performing the task is essential. This paper presents a on-line method for predicting energy requirements based on the pre-determined power models for a mobile robot. A small mobile robot, Khepera III is used for the experimental study and the results are promising with high prediction accuracy. The applications of the energy prediction models in energy optimization and simulations are also discussed along with examples of significant energy savings.

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Glial-cell-line-derived neurotrophic factor (GDNF) is a potent neurotrophic factor for adult nigral dopamine neurons in vivo. GDNF has both protective and restorative effects on the nigro-striatal dopaminergic (DA) system in animal models of Parkinson disease. Appropriate administration of this factor is essential for the success of its clinical application. Since it cannot cross the blood–brain barrier, a gene transfer method may be appropriate for delivery of the trophic factor to DA cells. We have constructed a recombinant adenovirus (Ad) encoding GDNF and injected it into rat striatum to make use of its ability to infect neurons and to be retrogradely transported by DA neurons. Ad-GDNF was found to drive production of large amounts of GDNF, as quantified by ELISA. The GDNF produced after gene transfer was biologically active: it increased the survival and differentiation of DA neurons in vitro. To test the efficacy of the Ad-mediated GDNF gene transfer in vivo, we used a progressive lesion model of Parkinson disease. Rats received injections unilaterally into their striatum first of Ad and then 6 days later of 6-hydroxydopamine. We found that mesencephalic nigral dopamine neurons of animals treated with the Ad-GDNF were protected, whereas those of animals treated with the Ad-β-galactosidase were not. This protection was associated with a difference in motor function: amphetamine-induced turning was much lower in animals that received the Ad-GDNF than in the animals that received Ad-β-galactosidase. This finding may have implications for the development of a treatment for Parkinson disease based on the use of neurotrophic factors.

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A recombinant adeno-associated virus (rAAV) vector capable of infecting cells and expressing rat glial cell line-derived neurotrophic factor (rGDNF), a putative central nervous system dopaminergic survival factor, under the control of a potent cytomegalovirus (CMV) immediate/early promoter (AAV-MD-rGDNF) was constructed. Two experiments were performed to evaluate the time course of expression of rAAV-mediated GDNF protein expression and to test the vector in an animal model of Parkinson’s disease. To evaluate the ability of rAAV-rGDNF to protect nigral dopaminergic neurons in the progressive Sauer and Oertel 6-hydroxydopamine (6-OHDA) lesion model, rats received perinigral injections of either rAAV-rGDNF virus or rAAV-lacZ control virus 3 weeks prior to a striatal 6-OHDA lesion and were sacrificed 4 weeks after 6-OHDA. Cell counts of back-labeled fluorogold-positive neurons in the substantia nigra revealed that rAAV-MD-rGDNF protected a significant number of cells when compared with cell counts of rAAV-CMV-lacZ-injected rats (94% vs. 51%, respectively). In close agreement, 85% of tyrosine hydroxylase-positive cells remained in the nigral rAAV-MD-rGDNF group vs. only 49% in the lacZ group. A separate group of rats were given identical perinigral virus injections and were sacrificed at 3 and 10 weeks after surgery. Nigral GDNF protein expression remained relatively stable over the 10 weeks investigated. These data indicate that the use of rAAV, a noncytopathic viral vector, can promote delivery of functional levels of GDNF in a degenerative model of Parkinson’s disease.

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Federal Highway Administration, Washington, D.C.

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Cultured human choriocarcinoma cells of the BeWo line exhibited saturable accumulation of radioiodide. Inhibition by competing anions followed the affinity series perchlorate >= iodide >= thiocyanate, consistent with uptake through the thyroid iodide transporter, NIS, whose messenger RNA was found in BeWo cells, and whose protein was distributed towards the apical pole of the cells. Efflux obeyed first order kinetics and was inhibited by DIDS, an antagonist of anion exchangers including pendrin, whose messenger RNA was also present. In cultures where iodide uptake through NIS was blocked with excess perchlorate, radiolodide accumulation was stimulated by exposure to medium in which physiological anions were replaced by 2-morpholinoethanesulfonic acid (MES), consistent with the operation of an anion exchange mechanism taking up iodide. Chloride in the medium was more effective than sulfate at inhibiting this uptake, matching the ionic specificity of pendrin. These studies provide evidence that the trophoblast accumulates iodide through NIS and releases it to the fetal compartment through pendrin. (c) 2004 Elsevier Ltd. All rights reserved.

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Purpose – A binary integer programming model for the simple assembly line balancing problem (SALBP), which is well known as SALBP-1, was formulated more than 30 years ago. Since then, a number of researchers have extended the model for the variants of assembly line balancing problem.The model is still prevalent nowadays mainly because of the lower and upper bounds on task assignment. These properties avoid significant increase of decision variables. The purpose of this paper is to use an example to show that the model may lead to a confusing solution. Design/methodology/approach – The paper provides a remedial constraint set for the model to rectify the disordered sequence problem. Findings – The paper presents proof that the assembly line balancing model formulated by Patterson and Albracht may lead to a confusing solution. Originality/value – No one previously has found that the commonly used model is incorrect.

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Abstract A new LIBS quantitative analysis method based on analytical line adaptive selection and Relevance Vector Machine (RVM) regression model is proposed. First, a scheme of adaptively selecting analytical line is put forward in order to overcome the drawback of high dependency on a priori knowledge. The candidate analytical lines are automatically selected based on the built-in characteristics of spectral lines, such as spectral intensity, wavelength and width at half height. The analytical lines which will be used as input variables of regression model are determined adaptively according to the samples for both training and testing. Second, an LIBS quantitative analysis method based on RVM is presented. The intensities of analytical lines and the elemental concentrations of certified standard samples are used to train the RVM regression model. The predicted elemental concentration analysis results will be given with a form of confidence interval of probabilistic distribution, which is helpful for evaluating the uncertainness contained in the measured spectra. Chromium concentration analysis experiments of 23 certified standard high-alloy steel samples have been carried out. The multiple correlation coefficient of the prediction was up to 98.85%, and the average relative error of the prediction was 4.01%. The experiment results showed that the proposed LIBS quantitative analysis method achieved better prediction accuracy and better modeling robustness compared with the methods based on partial least squares regression, artificial neural network and standard support vector machine.

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There is a paucity of literature regarding the construction and operation of corporate identity at the stakeholder group level. This article examines corporate identity from the perspective of an individual stakeholder group, namely, front-line employees. A stakeholder group that is central to the development of an organization’s corporate identity as it spans an organization’s boundaries, frequently interacts with both internal and external stakeholders, and influences a firm’s financial performance by building customer loyalty and satisfaction. The article reviews the corporate identity, branding, services and social identity literatures to address how corporate identity manifests within the front-line employee stakeholder group, identifying what components comprise front-line employee corporate identity and assessing what contribution front-line employees make to constructing a strong and enduring corporate identity for an organization. In reviewing the literature the article develops propositions that, in conjunction with a conceptual model, constitute the generation of theory that is recommended for empirical testing.

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Model Driven based approach for Service Evolution in Clouds will mainly focus on the reusable evolution patterns' advantage to solve evolution problems. During the process, evolution pattern will be driven by MDA models to pattern aspects. Weaving the aspects into service based process by using Aspect-Oriented extended BPEL engine at runtime will be the dynamic feature of the evolution.

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Stem cell therapy for ischaemic stroke is an emerging field in light of an increasing number of patients surviving with permanent disability. Several allogenic and autologous cells types are now in clinical trials with preliminary evidence of safety. Some clinical studies have reported functional improvements in some patients. After initial safety evaluation in a Phase 1 study, the conditionally immortalised human neural stem cell line CTX0E03 is currently in a Phase 2 clinical trial (PISCES-II). Previous pre-clinical studies conducted by ReNeuron Ltd, showed evidence of functional recovery in the Bilateral Asymmetry test up to 6 weeks following transplantation into rodent brain, 4 weeks after middle cerebral artery occlusion. Resting-state fMRI is increasingly used to investigate brain function in health and disease, and may also act as a predictor of recovery due to known network changes in the post-stroke recovery period. Resting-state methods have also been applied to non-human primates and rodents which have been found to have analogous resting-state networks to humans. The sensorimotor resting-state network of rodents is impaired following experimental focal ischaemia of the middle cerebral artery territory. However, the effects of stem cell implantation on brain functional networks has not previously been investigated. Prior studies assessed sensorimotor function following sub-cortical implantation of CTX0E03 cells in the rodent post-stroke brain but with no MRI assessments of functional improvements. This thesis presents research on the effect of sub-cortical implantation of CTX0E03 cells on the resting- state sensorimotor network and sensorimotor deficits in the rat following experimental stroke, using protocols based on previous work with this cell line. The work in this thesis identified functional tests of appropriate sensitivity for long-term dysfunction suitable for this laboratory, and investigated non-invasive monitoring of physiological variables required to optimize BOLD signal stability within a high-field MRI scanner. Following experimental stroke, rats demonstrated expected sensorimotor dysfunction and changes in the resting-state sensorimotor network. CTX0E03 cells did not improve post-stroke functional outcome (compared to previous studies) and with no changes in resting-state sensorimotor network activity. However, in control animals, we observed changes in functional networks due to the stereotaxic procedure. This illustrates the sensitivity of resting-state fMRI to stereotaxic procedures. We hypothesise that the damage caused by cell or vehicle implantation may have prevented functional and network recovery which has not been previously identified due to the application of different functional tests. The findings in this thesis represent one of few pre-clinical studies in resting-state fMRI network changes post-stroke and the only to date applying this technique to evaluate functional outcomes following a clinically applicable human neural stem cell treatment for ischaemic stroke. It was found that injury caused by stereotaxic injection should be taken into account when assessing the effectiveness of treatment.