Background: Dendritic spine morphology is heterogeneous and highly dynamic. To study the changing or aberrant morphology in test setups, often spines from several neurons from a few experimental units e.g. mice or pri...
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Background: Dendritic spine morphology is heterogeneous and highly dynamic. To study the changing or aberrant morphology in test setups, often spines from several neurons from a few experimental units e.g. mice or primary neuronal cultures are measured. This strategy results in a multilevel data structure, which, when not properly addressed, has a high risk of producing false positive and false negative findings. Methods: We used mixed-effects models to deal with data with a multilevel data structure and compared this method to analyses at each level. We apply these statistical tests to a dataset of dendritic spine morphology parameters to illustrate advantages of multilevel mixed-effects model, and disadvantages of other models. Results: We present an application of mixed-effects models for analyzing dendritic spine morphology datasets while correcting for the data structure. Comparison with existing methods: We further show that analyses at spine level and aggregated levels do not adequately account for the data structure, and that they may lead to erroneous results. Conclusion: We highlight the importance of data structure in dendritic spine morphology analyses and highly recommend the use of mixed-effects models or other appropriate statistical methods to deal with multilevel datasets. Mixed-effects models are easy to use and superior to commonly used methods by including the data structure and the addition of other explanatory variables, for example sex, and age, etc., as well as interactions between variables or between variables and level identifiers. (C) 2018 Elsevier B.V. All rights reserved.
This correspondence presents the results of an experimental investigation into the comparative usefulness of textual tools (what Yourdon calls 'data dictionaries') and graphical tools (what Yourdon calls '...
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This correspondence presents the results of an experimental investigation into the comparative usefulness of textual tools (what Yourdon calls 'data dictionaries') and graphical tools (what Yourdon calls 'data structure diagrams') for the program understanding phase of Cobol program maintenance. Both novice and experienced programmers were used as subjects. The results showed a slight superiority for graphical tools when used by less experienced programmers. It casts doubt on the importance of rigid adherence to program design methodologies for experienced programmers, and on the extensibility of experiments using relatively inexperienced student subjects. [ABSTRACT FROM AUTHOR]
Transition from the iconic representation of a scene to be analyzed to a symbolic description of relevant primitives is an important step in many concepts for image analysis. A data structure is described consisting o...
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Transition from the iconic representation of a scene to be analyzed to a symbolic description of relevant primitives is an important step in many concepts for image analysis. A data structure is described consisting of connected regions and lines as most obvious kinds of primitive elements for representing images in a general symbolic form. Methods for creating such kind of description and possibilities for managing these data in an appropriate form are described exemplarily.
A data structure representing assemblies in a database can be divided into two parts. The first part is the data structure used to store topological and geometric information on each component in an assembly. The seco...
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A data structure representing assemblies in a database can be divided into two parts. The first part is the data structure used to store topological and geometric information on each component in an assembly. The second part is the data structure used to store information on how all the components in an assembly are connected. Any existing ‘boundary representation’ scheme can be used to represent each component. In this paper, a winged-edge data representation with extensions to handle multiply-connected faces is recommended. A tree structure using the concept of ‘virtual link’ is created to represent the relationships between the components in an assembly.
Background: The increasing application of next generation sequencing technologies has led to the availability of thousands of reference genomes, often providing multiple genomes for the same or closely related species...
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Background: The increasing application of next generation sequencing technologies has led to the availability of thousands of reference genomes, often providing multiple genomes for the same or closely related species. The current approach to represent a species or a population with a single reference sequence and a set of variations cannot represent their full diversity and introduces bias towards the chosen reference. There is a need for the representation of multiple sequences in a composite way that is compatible with existing data sources for annotation and suitable for established sequence analysis methods. At the same time, this representation needs to be easily accessible and extendable to account for the constant change of available genomes. Results: We introduce seq-seq-pan, a framework that provides methods for adding or removing new genomes from a set of aligned genomes and uses these to construct a whole genome alignment. Throughout the sequential workflow the alignment is optimized for generating a representative linear presentation of the aligned set of genomes, that enables its usage for annotation and in downstream analyses. Conclusions: By providing dynamic updates and optimized processing, our approach enables the usage of whole genome alignment in the field of pan-genomics. In addition, the sequential workflow can be used as a fast alternative to existing whole genome aligners for aligning closely related genomes. seq-seq-pan is freely available at https://***/rki_bioinformatics
In this paper we explore the use of weak B-trees to represent sorted lists. In weak B-trees each node has at least a and at most b sons where 2a≦b. We analyse the worst case cost of sequences of insertions and deleti...
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In this paper we explore the use of weak B-trees to represent sorted lists. In weak B-trees each node has at least a and at most b sons where 2a≦b. We analyse the worst case cost of sequences of insertions and deletions in weak B-trees. This leads to a new data structure (level-linked weak B-trees) for representing sorted lists when the access pattern exhibits a (time-varying) locality of reference. Our structure is substantially simpler than the one proposed in [7], yet it has many of its properties. Our structure is as simple as the one proposed in [5], but our structure can treat arbitrary sequences of insertions and deletions whilst theirs can only treat non-interacting insertions and deletions. We also show that weak B-trees support concurrent operations in an efficient way.
In Grids, users may require assurance for completing their jobs on shared resources. Such guarantees can only be provided by reserving resources in advance. However, if many reservation requests arrive at a resource s...
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In Grids, users may require assurance for completing their jobs on shared resources. Such guarantees can only be provided by reserving resources in advance. However, if many reservation requests arrive at a resource simultaneously, the overhead of providing such service due to adding, deleting and searching, will be significant. An efficient data structure for managing these reservations plays an important role in order to minimise the time required for searching available resources, adding and deleting reservations. In this paper, we present new approaches to advance reservation in order to deal with the limitations of the existing data structures, such as Segment Tree and Calendar Queue in similar problems. We propose a Grid advanced reservation Queue (GarQ), which is a new data structure that improves some weaknesses of the aforementioned data structures. We demonstrate the superiority of the proposed structure by conducting a detailed performance evaluation on real workload traces.
A new generation computer is expected to be the knowledge processing system of the future. However, many aspects are yet unknown regarding this technology, and a number of fundamental concepts, directly concerning kno...
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A new generation computer is expected to be the knowledge processing system of the future. However, many aspects are yet unknown regarding this technology, and a number of fundamental concepts, directly concerning knowledge processing system design need investigation, such as knowledge, data, inference, communication, information management, learning, and human interface.
datasets are sometimes divided into distinct subsets, e.g. due to multi-center sampling, or to variations in instruments, questionnaire item ordering or mode of administration, and the data analyst then needs to asses...
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datasets are sometimes divided into distinct subsets, e.g. due to multi-center sampling, or to variations in instruments, questionnaire item ordering or mode of administration, and the data analyst then needs to assess whether a joint analysis is meaningful. The Principal Component Analysis-based data structure Comparisons (PCADSC) tools are three new non-parametric, visual diagnostic tools for investigating differences in structure for two subsets of a dataset through covariance matrix comparisons by use of principal component analysis. The PCADCS tools are demonstrated in a data example using European Social Survey data on psychological well-being in three countries, Denmark, Sweden, and Bulgaria. The data structures are found to be different in Denmark and Bulgaria, and thus a comparison of for example mean psychological well-being scores is not meaningful. However, when comparing Denmark and Sweden, very similar data structures, and thus comparable concepts of well-being, are found. Therefore, inter-country comparisons are warranted for these countries.
Previous research indicates that understanding the state of learning motivation enables researchers to deeply understand students' learning processes. Studies have shown that visual programming languages use graph...
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Previous research indicates that understanding the state of learning motivation enables researchers to deeply understand students' learning processes. Studies have shown that visual programming languages use graphical code, enabling learners to learn effectively, improve learning effectiveness, increase learning fun, and offering various other advantages. This study is a counterbalanced experiment on the students of a class, conducted in three stages. The first stage examines the students' initial motivation states. In the second stage, students use a traditional programming language before a visual programming language to learn a specific data structure topic. Finally, in the third stage, students use a visual programming language before a traditional programming language to learn another specific data structure topic. After collecting the experimental data, we cross analyzed questionnaire results to observe whether there was any correlation between them. We found that the motivation state at stages two and three were significantly higher than at stage one. It can be deduced that the use of a visual programming language in a data structure course has a significant effect on improving learning motivation.
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