نتایج جستجو برای: structural models

تعداد نتایج: 1266837  

Journal: :Statistics in medicine 2012
W G Havercroft V Didelez

We discuss why it is not always obvious how to simulate longitudinal data from a general marginal structural model (MSM) for a survival outcome while ensuring that the data exhibit complications due to time-dependent confounding. On the basis of the relation between a directed acyclic graph and an MSM, we suggest a data-generating process that satisfies both these requirements, the general vali...

Journal: :Philosophical transactions. Series A, Mathematical, physical, and engineering sciences 2010
Detlef Schooss Patrick Weis Oliver Hampe Manfred M Kappes

Ligand-free metal clusters can be prepared over a wide size range, but only in comparatively small amounts. Determining their size-dependent properties has therefore required the development of experimental methods that allow characterization of sample sizes comprising only a few thousand mass-selected particles under well-defined collision-free conditions. In this review, we describe the appli...

2017
William C. Hacker Shuxiang Li Adrian H. Elcock

We describe structural models of the Escherichia coli chromosome in which the positions of all 4.6 million nucleotides of each DNA strand are resolved. Models consistent with two basic chromosomal orientations, differing in their positioning of the origin of replication, have been constructed. In both types of model, the chromosome is partitioned into plectoneme-abundant and plectoneme-free reg...

2009
Emily Whiting John Ochsendorf Frédo Durand

We introduce structural feasibility into procedural modeling of buildings. This allows for more realistic structural models that can be interacted with in physical simulations. While existing structural analysis tools focus heavily on providing an analysis of the stress state, our proposed method automatically tunes a set of designated free parameters to obtain forms that are structurally sound.

2010
Tyler J. VanderWeele Stijn Vansteelandt James M. Robins

Sufficient cause interactions concern cases in which there is a particular causal mechanism for some outcome that requires the presence of 2 or more specific causes to operate. Empirical conditions have been derived to test for sufficient cause interactions. However, when regression outcome models are used to control for confounding variables in tests for sufficient cause interactions, the outc...

2005
H. S. Lew

This paper presents simple analytical approaches for evaluating progressive collapse potential of lowand mid-rise buildings that could be used in routine design by design professionals. Although nonlinear time history analysis would be more realistic in representing progressive collapse phenomenon, high fidelity structural models to represent nonlinear structural behavior are required to produc...

Journal: :Acta crystallographica. Section D, Biological crystallography 2006
Karsten Suhre Jorge Navaza Yves Henri Sanejouand

This paper describes a freely available software suite that allows the modelling of large conformational changes of high-resolution three-dimensional protein structures under the constraint of a low-resolution electron-density map. Typical applications are the interpretation of electron-microscopy data using atomic scale X-ray structural models. The software package provided should enable the i...

Journal: :Psychological methods 2017
Sonya K Sterba Jason D Rights

Research interest often lies in comparing structural model specifications implying different relationships among latent factors. In this context parceling is commonly accepted, assuming the item-level measurement structure is well known and, conservatively, assuming items are unidimensional in the population. Under these assumptions, researchers compare competing structural models, each specifi...

Journal: :NeuroImage 2006
Elena Rykhlevskaia Monica Fabiani Gabriele Gratton

Most cognitive processes are supported by large networks of brain regions. To describe the operation of these networks, it is critical to understand how individual areas are functionally connected. Here, we establish a statistical framework for studying effective and functional brain connectivity, using data obtained with a relatively new neuroimaging method, the event-related optical signal (E...

2013
Piotr Lukasiak Maciej Antczak Tomasz Ratajczak Janusz M. Bujnicki Marta Szachniuk Ryszard W. Adamiak Mariusz Popenda Jacek Blazewicz

The continuously increasing amount of RNA sequence and experimentally determined 3D structure data drives the development of computational methods supporting exploration of these data. Contemporary functional analysis of RNA molecules, such as ribozymes or riboswitches, covers various issues, among which tertiary structure modeling becomes more and more important. A growing number of tools to m...

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