共查询到20条相似文献,搜索用时 31 毫秒
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A key point in the analysis of dynamical models of biological systems is to handle systems of relatively high dimensions.
In the present paper we propose a method to hierarchically organize a certain type of piecewise affine (PWA) differential
systems. This specific class of systems has been extensively studied for the past few years, as it provides a good framework
to model gene regulatory networks. The method, shown on several examples, allows a qualitative analysis of the asymptotic
behavior of a PWA system, decomposing it into several smaller subsystems. This technique, based on the well-known strongly
connected components decomposition, is not new. However, its adaptation to the non-smooth PWA differential equations turns
out to be quite relevant because of the strong discrete structure underlying these equations. Its biological relevance is
shown on a 7-dimensional PWA system modeling the gene network responsible for the carbon starvation response in Escherichia coli.
相似文献
Laurent Tournier (Corresponding author)Email: |
Jean-Luc GouzéEmail: |
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Rapid prototyping of distributed systems can be achieved by integrating commercial off-the-shelf (COTS) components. With components
as the building blocks, it is important to predict the performance of the system based on the performance of individual components.
In this paper, performance prediction of a system consisting of a small number of components is investigated under different
inter-component communication patterns, and the number of threads provided by components. Based on the experimental results,
it can be inferred that the proposed composition rules provide a reasonably accurate prediction of the performance of a system
made out of these components.
相似文献
Barrett R. BryantEmail: |
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Leslie P. Francis Margaret P. Battin Jay Jacobson Charles Smith 《Journal of bioethical inquiry》2009,6(2):187-195
Syndromic surveillance uses new ways of gathering data to identify possible disease outbreaks. Because syndromic surveillance
can be implemented to detect patterns before diseases are even identified, it poses novel problems for informed consent, patient
privacy and confidentiality, and risks of stigmatization. This paper analyzes these ethical issues from the viewpoint of the
patient as victim and vector. It concludes by pointing out that the new International Health Regulations fail to take full
account of the ethical challenges raised by syndromic surveillance.
相似文献
Leslie P. FrancisEmail: |
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Sub-Antarctic Marion Island has had a permanent research station for 50 years and the islands Wandering Albatrosses have been intensively studied for 20 years. The reactions of breeding birds to approaches by a human on foot were recorded. Three response variables were calculated: intensity of vocal reaction (IVR), intensity of non-vocal reaction (INR) and overall response index (ORI). At 5 m from the nest, twice as many birds stood and/or vocalised as at 15 m. Nearest neighbour distance, age and gender did not explain individual variability of responses. Study colony birds had higher IVR scores than non-study colony birds; birds at colonies closest to the station had the highest ORI scores. A better breeding record was associated with lower IVR and ORI scores, but a causative relationship remains to be demonstrated. A minimum viewing distance of 25 m is recommended for breeding Wandering Albatrosses.
相似文献
Marienne S. de VilliersEmail: Fax: +27-21-6503434 |
John CooperEmail: |
Peter G. RyanEmail: |
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Viraj Bhat Manish Parashar Hua Liu Nagarajan Kandasamy Mohit Khandekar Scott Klasky Sherif Abdelwahed 《Cluster computing》2007,10(4):365-383
Efficient and robust data streaming services are a critical requirement of emerging Grid applications, which are based on
seamless interactions and coupling between geographically distributed application components. Furthermore the dynamism of
Grid environments and applications requires that these services be able to continually manage and optimize their operation
based on system state and application requirements. This paper presents a design and implementation of such a self-managing
data-streaming service based on online control strategies. A Grid-based fusion workflow scenario is used to evaluate the service
and demonstrate its feasibility and performance.
相似文献
Sherif AbdelwahedEmail: |
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T. Ryan Gregory 《Evolution》2008,1(4):358-389
The origin of complex biological structures has long been a subject of interest and debate. Two centuries ago, natural explanations
for their occurrence were considered inconceivable. However, 150 years of scientific investigation have yielded a conceptual
framework, abundant data, and a range of analytical tools capable of addressing this question. This article reviews the various
direct and indirect evolutionary processes that contribute to the origins of complex organs. The evolution of eyes is used
as a case study to illustrate these concepts, and several of the most common misconceptions about complex organ evolution
are discussed.
相似文献
T. Ryan GregoryEmail: |
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The recent contribution by Jarmila Kukalová-Peck on Hennigian phylogenetics and hexapod limb evolution is critically evaluated.
相似文献
Michael S. Engel (Corresponding author)Email: |
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Peter Godfrey-Smith 《Biology & philosophy》2007,22(3):429-437
Jablonka and Lamb's claim that evolutionary biology is undergoing a ‘revolution’ is queried. But the very concept of revolutionary
change has uncertain application to a field organized in the manner of contemporary biology. The explanatory primacy of sequence
properties is also discussed.
相似文献
Peter Godfrey-SmithEmail: |
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Terry Harmer 《Cluster computing》2007,10(3):277-285
Gridcast is an R&D project investigating grid ideas and technologies in the broadcasting technical infrastructure. In this
paper I discuss the business and technical issues in building infrastructures to support broadcasters and outline the structure
of the Gridcast grid-based service oriented architecture for broadcasting playout support.
相似文献
Terry HarmerEmail: |
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Roger Sansom 《Biology & philosophy》2008,23(4):475-491
I show that gene regulation networks are qualitatively consistent and therefore sufficiently similar to linearly seperable
connectionist networks to warrant that the connectionist framework be applied to gene regulation. On this view, natural selection
designs gene regulation networks to overcome the difficulty of development. I offer some general lessons about their evolvability
that can be learned by examining the generic features of connectionist networks.
相似文献
Roger SansomEmail: |
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Causal Explanation of Indonesian Forest Fires: Concepts, Applications, and Research Priorities 总被引:1,自引:0,他引:1
Andrew P. Vayda 《Human ecology: an interdisciplinary journal》2006,34(5):615-635
Problems with studies, claims, and assumptions that have been made about the causes of fires in Indonesia's tropical moist forests are identified, and the kinds of concepts, methods, prioritizing, and data needed to resolve the problems are discussed. Separate sections are devoted to studying ignitions, studying fire susceptibility and fire behavior, and using the goal of causal explanation to guide interdisciplinary research.
相似文献
Andrew P. VaydaEmail: |
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Large-scale scientific computing applications frequently make use of closely-coupled distributed parallel components. The
performance of such applications is therefore dependent on the component parts and their interaction at run-time. This paper
describes a methodology for predictive performance modelling and evaluation of parallel applications composed of multiple
interacting components. In this paper, the fundamental steps and required operations involved in the modelling and evaluation
process are identified—including component decomposition, component model combination, M×N communication modelling, dataflow analysis and overall performance evaluation. A case study is presented to illustrate the
modelling process and the methodology is verified through experimental analysis.
相似文献
Stephen A. JarvisEmail: |
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Tanya Marie Hayes 《Human ecology: an interdisciplinary journal》2007,35(6):733-747
This article compares how public protection of forests and common-property forest institutions serve to control outside encroachment
into frontier forests in Honduras and Nicaragua. The article combines institutional analysis with ethnographically based fieldwork
and analysis of land-cover images to evaluate how property-rights arrangements influence monitoring, enforcement, and compliance
with rules to restrict agricultural expansion in two biosphere reserves in the Mosquitia Corridor. Findings show that territorial
demarcation and common-property rights are important components for frontier forest conservation. In areas with weak enforcement
mechanisms and heavy reliance on social norms over official regulatory measures, the findings suggest that the perceived legitimacy
of tenure arrangements and their respective land-use rules are fundamental to controlling the agricultural frontier.
相似文献
Tanya Marie HayesEmail: |
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Anthropologists and psychiatrists traditionally have used the salience of a mind–body dichotomy to distinguish Western from
non-Western ethnopsychologies. However, despite claims of mind–body holism in non-Western cultures, mind–body divisions are
prominent in non-Western groups. In this article, we discuss three issues: the ethnopsychology of mind–body dichotomies in
Nepal, the relationship between mind–body dichotomies and the hierarchy of resort in a medical pluralistic context, and, finally,
the role of mind–body dichotomies in public health interventions (biomedical and psychosocial) aimed toward decreasing the
stigmatization of mental illness. We assert that, by understanding mind–body relations in non-Western settings, their implications,
and ways in which to reconstitute these relations in a less stigmatizing manner, medical anthropologists and mental health
workers can contribute to the reduction of stigma in global mental health care.
相似文献
Brandon A. KohrtEmail: |
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Event-related brain potentials (ERP) are important neural correlates of cognitive processes. In the domain of language processing,
the N400 and P600 reflect lexical-semantic integration and syntactic processing problems, respectively. We suggest an interpretation
of these markers in terms of dynamical system theory and present two nonlinear dynamical models for syntactic computations
where different processing strategies correspond to functionally different regions in the system’s phase space.
相似文献
Peter beim GrabenEmail: |
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Debates over adaptationism can be clarified and partially resolved by careful consideration of the ‘grain’ at which evolutionary
processes are described. The framework of ‘adaptive landscapes’ can be used to illustrate and facilitate this investigation.
We argue that natural selection may have special status at an intermediate grain of analysis of evolutionary processes. The
cases of sickle-cell disease and genomic imprinting are used as case studies.
相似文献
Peter Godfrey-SmithEmail: |