Speed of reaction diffusion in embryogenesis

Reaction diffusion systems have been proposed as mechanisms for patterning during many stages of embryonic development. While much attention has been focused on the study of the steady state patterns formed and the robustness of pattern selection, much less is known about the time scales required for pattern formation. Studies of gradient formation by the diffusion of a single morphogen from a localized source have shown that patterning can occur on realistic time scales over distances of a millimeter or less. Reaction diffusion has the potential to give rise to patterns on a faster time scale, since all points in the domain can act as sources of morphogen. However, the speed at which patterning can occur has hitherto not been explored in depth. In this paper, we investigate this issue in specific reaction diffusion models and address the question of whether patterning via reaction diffusion is fast enough to be applicable to morphogenesis

Complex pattern formation in reaction diffusion systems with spatially-varying parameters

Spontaneous pattern formation in reaction–diffusion systems on a spatially homogeneous domain has been well studied. However, in embryonic development and elsewhere, pattern formation often takes place on a spatially heterogeneous background. We explore the effects of spatially varying parameters on pattern formation in one and two dimensions using the Gierer–Meinhardt reaction–diffusion model. We investigate the effect of the wavelength of a pre-pattern and demonstrate a novel form of moving pattern. We find that spatially heterogeneous parameters can both increase the range and complexity of possible patterns and enhance the robustness of pattern selection

Anatomy of Creative Commons Licenses

In this presentation we will explore the anatomy of Creative Commons licenses through coming to understand six key areas. These areas are: 1.What is Creative Commons (CC)? 2.Three layers of the CC licenses 3.Four license elements and their icons 4.Six Creative Commons licenses 5.CC licenses affect on copyright exceptions and limitations 6.CC licenses affect on works in the public domai

Easy as 1,2,3: Create your own journal/ event pages with DigitalCommons@UNO

Creating a journal or event page with DigitalCommons is as easy as 1,2,3! Journal/ event pages on DigitalCommons@UNO possess similar features. These features help you to: •Create more impact •Create opportunities for outreach •Save time on administrative task

What is Creative Commons?

What is Creative Commons? is a presentation discussing the background and purpose of Creative Commons

Using Creative Commons Licenses and Creative Commons Licensed Works

Understanding the difference between collections and derivative works is key to your reuse and adaptation of existing material. It is often useful to create collections and derivative works for educational purposes; for instance, you may wish to compile a collection of articles or adapt an existing educational source to serve as a course text. However, it is not always possible to do both or any, depending on copyright restrictions. This presentation will guide your use and re-use of material that hold a Creative Commons license. In this presentation we will answer the questions What are collections and what are derivative works? We will also provide examples of collections and derivative works, along with providing tools for how to navigate reuse with the adapter\u27s license chart and the license compatibility chart

Investing in Knowledge: The Benefits of an Open Access Fund

This presentation will discuss the strengths and weaknesses of the University of Nebraska at Omaha Open Access Fund through analysis of the disciplinary diversity of applicants, eligibility guidelines, funding limit and the benefits of publishing Open Access. Furthermore, it will seek to discover ways to increase participation in the Open Access Fund and by extension, the institutional repository, through comparison with other universities’ OA funds

A NuSTAR observation of the fast symbiotic nova V745 Sco in outburst

The fast recurrent nova V745 Sco was observed in the 3-79 keV X-rays band with NuSTAR 10 days after the optical discovery. The measured X-ray emission is consistent with a collisionally ionized optically thin plasma at temperature of about 2.7 keV. A prominent iron line observed at 6.7 keV does not require enhanced iron in the ejecta. We attribute the X-ray flux to shocked circumstellar material. No X-ray emission was observed at energies above 20 keV, and the flux in the 3-20 keV range was about 1.6 $\times$ 10$^{-11}$ erg cm$^{-2}$ s$^{-1}$. The emission measure indicates an average electron density of order of 10$^7$ cm$^{-3}$. The X-ray flux in the 0.3-10 keV band almost simultaneously measured with Swift was about 40 times larger, mainly due to the luminous central supersoft source emitting at energy below 1 keV. The fact that the NuSTAR spectrum cannot be fitted with a power law, and the lack of hard X-ray emission, allow us to rule out Comptonized gamma rays, and to place an upper limit of the order of 10$^{-11}$ erg cm$^{-2}$ s$^{-1}$ on the gamma-ray flux of the nova on the tenth day of the outburst.Comment: in press in Monthly Notices of the Royal Astronomical Society, 201

Unifying Parsimonious Tree Reconciliation

Evolution is a process that is influenced by various environmental factors, e.g. the interactions between different species, genes, and biogeographical properties. Hence, it is interesting to study the combined evolutionary history of multiple species, their genes, and the environment they live in. A common approach to address this research problem is to describe each individual evolution as a phylogenetic tree and construct a tree reconciliation which is parsimonious with respect to a given event model. Unfortunately, most of the previous approaches are designed only either for host-parasite systems, for gene tree/species tree reconciliation, or biogeography. Hence, a method is desirable, which addresses the general problem of mapping phylogenetic trees and covering all varieties of coevolving systems, including e.g., predator-prey and symbiotic relationships. To overcome this gap, we introduce a generalized cophylogenetic event model considering the combinatorial complete set of local coevolutionary events. We give a dynamic programming based heuristic for solving the maximum parsimony reconciliation problem in time O(n^2), for two phylogenies each with at most n leaves. Furthermore, we present an exact branch-and-bound algorithm which uses the results from the dynamic programming heuristic for discarding partial reconciliations. The approach has been implemented as a Java application which is freely available from http://pacosy.informatik.uni-leipzig.de/coresym.Comment: Peer-reviewed and presented as part of the 13th Workshop on Algorithms in Bioinformatics (WABI2013