551 research outputs found
Structural Characterisation of the Drosophila Mushroom Bodies
The brain of the fruit fly Drosophila melanogaster, although only comprising some 200 thousand neurons, displays a remarkable repertoire of behavioural responses to it's environment. The relative simplicity of it's brain structure in comparison with vertebrate models or even higher invertebrates, wealth of genetic data and availability of both quantitative and qualitative behavioural assays, make it an ideal model organism for studying brain structure/function relationships. The recent development of P-element based enhancer-trap technology has provided a new tool both for visualisation and for manipulation of neurons. This technology has been used here to investigate the structure of the mushroom bodies. One of the major regions of higher function in the insect brain, the mushroom bodies have been compared to the mammalian hippocampus. Confocal microscopy of enhancer-trap expression pattems reveals neuronal structure to a higher degree of resolution than is possible usin most traditional neuroanatomical techniques. A total of 31 P{GAL4} enhancer-trap lines isolated from a screen of 1800 were chosen for detailed analysis. Structural subdivisions in terms of gene expression invisible to classical neuroanatomy are evident, suggesting a possible degree of functional subdivision. The expression pattems in the larval mushroom bodies also show subdivisions. The nature of the subdivisions are different at the two developmental stages. Analysis of the developing brain during the pupal stages illustrates the structural re-organisation of the mushroom bodies during this period. Hydroxyurea ablation of the mushroom body neuroblasts in the early larvae results in a small renuiant that survives from the embryo to the adult Extrinsic output from the mb lobes and input to the calyx appears unaffected by the ablation of the mushroom bodies. Partial ablation of the neuroblasts provides evidence that the four fold symmetry of the mb structure is a reflection of the clonal nature of each of the four clusters and tracts and that the mushroom bodies are closely related to the lower order olfactory centre, the antennal lobes
BioNAR: an integrated biological network analysis package in bioconductor
Motivation
Biological function in protein complexes emerges from more than just the sum of their parts: molecules interact in a range of different sub-complexes and transfer signals/information around internal pathways. Modern proteomic techniques are excellent at producing a parts-list for such complexes, but more detailed analysis demands a network approach linking the molecules together and analysing the emergent architectural properties. Methods developed for the analysis of networks in social sciences have proven very useful for splitting biological networks into communities leading to the discovery of sub-complexes enriched with molecules associated with specific diseases or molecular functions that are not apparent from the constituent components alone.
Results
Here, we present the Bioconductor package BioNAR, which supports step-by-step analysis of biological/biomedical networks with the aim of quantifying and ranking each of the network’s vertices based on network topology and clustering. Examples demonstrate that while BioNAR is not restricted to proteomic networks, it can predict a protein’s impact within multiple complexes, and enables estimation of the co-occurrence of metadata, i.e. diseases and functions across the network, identifying the clusters whose components are likely to share common function and mechanisms.
Availability and implementation
The package is available from Bioconductor release 3.17: https://bioconductor.org/packages/release/bioc/html/BioNAR.html.journal articl
Characterization of wetting using topological principles
Hypothesis Understanding wetting behavior is of great importance for natural
systems and technological applications. The traditional concept of contact
angle, a purely geometrical measure related to curvature, is often used for
characterizing the wetting state of a system. It can be determined from Young's
equation by applying equilibrium thermodynamics. However, whether contact angle
is a representative measure of wetting for systems with significant complexity
is unclear. Herein, we hypothesize that topological principles based on the
Gauss-Bonnet theorem could yield a robust measure to characterize wetting.
Theory and Experiments We introduce a macroscopic contact angle based on the
deficit curvature of the fluid interfaces that are imposed by contacts with
other immiscible phases. We perform sessile droplet simulations followed by
multiphase experiments for porous sintered glass and Bentheimer sandstone to
assess the sensitivity and robustness of the topological approach and compare
the results to other traditional approaches.
Findings We show that the presented topological principle is consistent with
thermodynamics under the simplest conditions through a variational analysis.
Furthermore, we elucidate that at sufficiently high image resolution the
proposed topological approach and local contact angle measurements are
comparable. While at lower resolutions, the proposed approach provides more
accurate results being robust to resolution-based effects. Overall, the
presented concepts open new pathways to characterize the wetting state of
complex systems and theoretical developments to study multiphase systems.Comment: 11 pages, 9 figures, 1 tabl
Nonfatal Strangulation in a Sample of Domestically Violent Stalkers: The Importance of Recognizing Coercively Controlling Behaviors
© 2019 International Association for Correctional and Forensic Psychology. Strangulation is different to other types of physical violence as it often leaves no visible injuries and is frequently motivated by coercive control. Few studies have explored nonfatal strangulation and coercive control, and no studies have explored these factors within a sample of stalkers. Given that stalking perpetrators exhibit many of the coercively controlling behaviors related to nonfatal strangulation, the current study explored nonfatal strangulation and other coercively controlling behaviors in a stalking sample. A police dataset of 9,884 cases of domestic violence that involved stalking was analyzed. Results revealed that coercive control and related behaviors of excessive jealousy, victim isolation, victim fear, and victim’s belief that the perpetrator will kill them were associated with higher likelihood of having experienced nonfatal strangulation. These results may help first responders to identify victims at risk of nonfatal strangulation and suggest a need for nonfatal strangulation to be a criminal offense
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Lewy Body Dementia Association\u27s Research Centers of Excellence Program: Inaugural Meeting Proceedings.
The first Lewy Body Dementia Association (LBDA) Research Centers of Excellence (RCOE) Investigator\u27s meeting was held on December 14, 2017, in New Orleans. The program was established to increase patient access to clinical experts on Lewy body dementia (LBD), which includes dementia with Lewy bodies (DLB) and Parkinson\u27s disease dementia (PDD), and to create a clinical trials-ready network. Four working groups (WG) were created to pursue the LBDA RCOE aims: (1) increase access to high-quality clinical care, (2) increase access to support for people living with LBD and their caregivers, (3) increase knowledge of LBD among medical and allied (or other) professionals, and (4) create infrastructure for a clinical trials-ready network as well as resources to advance the study of new therapeutics
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