Supplementary data are available at Bioinformatics online.
We introduce Forman-Ricci curvature and its corresponding flow as characteristics for complex networks attempting to extend the common approach of node-based network analysis by edge-based characteristics. Following a theoretical introduction and mathematical motivation, we apply the proposed network-analytic methods to static and dynamic complex networks and compare the results with established node-based characteristics. Our work suggests a number of applications for data mining, including denoising and clustering of experimental data, as well as extrapolation of network evolution. Complex networks, Forman-Ricci-curvature, Ricci-flow, Laplacian flow, data mining 2000 Math Subject Classification: 05C82, 05C75, 05C21, 05C10Network graphs have been perceived as practical models for complex systems for decades. With the rapid rise of data science since the late 1990s, they have become a widely used form of data representation that is easily storable and can be effectively analyzed with data mining methods.Complex networks represent a wide variety of data sets and systems, ranging from social interactions in large online social networks like Facebook and Twitter to neuronal activities in cortical graphs and genetic interactions in the human genome. Outside the social and natural sciences, networks are used as models for the spread of information in the world wide web and the shared use of energy ressources -to name just a few examples.Since the early days of network sciences, there have been numerous attempts to characterize complex real-world networks with standard models that capture essential topological properties. Most notably are the models of P. Rényi, 1959, Erdős andRényi, 1960], D. Watts and S. Strogatz [Watts and Strogatz, 1998] and R. Albert and A. Barabási [Barabási and Albert, 1999]. Their efforts were addressed with both praise 1 arXiv:1607.08654v2 [cs.DM]
The purpose of this study was to evaluate school nurses' familiarity and perceptions regarding academic accommodations for student-athletes following sport-related concussion. School nurses (N = 1,246) accessed the survey School Nurses' Beliefs, Attitudes and Knowledge of Pediatric Athletes with Concussions (BAKPAC-SN). The BAKPAC-SN contained several questions pertaining to concussion management and academic accommodations. There were significant differences regarding personal experience as well as familiarity of academic accommodations (p < .001) between school nurses who work at a school that employs an athletic trainer and school nurses who work at a school that does not employ an athletic trainer. There were significant weak positive relationships between years of experience and familiarity with academic accommodations (r = .210, p < .001), 504 plans (r = .243, p < .001), and individualized education plans (r = .205, p < .001). School nurses employed at a single school were significantly more familiar with academic accommodations (p = .027) and 504 plans (p = .001) than school nurses employed at multiple schools. Health care professionals should collaborate to effectively manage a concussed patient and should consider academic accommodations to ensure whole-person health care.
At present, it is not clear how memory B lymphocytes are maintained over time, and whether only as circulating cells or also residing in particular tissues. Here we describe distinct populations of isotype-switched memory B lymphocytes (Bsm) of murine spleen and bone marrow, identified according to individual transcriptional signature and B cell receptor repertoire. A population of marginal zone-like cells is located exclusively in the spleen, while a population of quiescent Bsm is found only in the bone marrow. Three further resident populations, present in spleen and bone marrow, represent transitional and follicular B cells and B1 cells, respectively. A population representing 10-20% of spleen and bone marrow memory B cells is the only one qualifying as circulating. In the bone marrow, all cells individually dock onto VCAM1 + stromal cells and, reminiscent of resident memory T and plasma cells, are void of activation, proliferation and mobility.
Postinjury sleep declines may be associated with symptom severity and worsened reaction time during initial stages of recovery or may be the result of the concussion itself. Clinicians should be aware of alterations in sleep duration and manage appropriately to mitigate initial symptom burden postconcussion.
While lattice QCD allows for reliable results at small momentum transfers (large quark separations), perturbative QCD is restricted to large momentum transfers (small quark separations). The latter is determined up to a reference momentum scale Λ, which is to be provided from outside, e.g. from experiment or lattice QCD simulations. In this article, we extract Λ MS for QCD with n f = 2 dynamical quark flavors by matching the perturbative static quark-antiquark potential in momentum space to lattice results in the intermediate momentum regime, where both approaches are expected to be applicable. In a second step, we combine the lattice and the perturbative results to provide a complete analytic parameterization of the static quark-antiquark potential in position space up to the string breaking scale. As an exemplary phenomenological application of our all-distances potential we compute the bottomonium spectrum in the static limit.
Obsessive-compulsive disorder (OCD) is a common neuropsychiatric disease affecting about 2% of the general population. It is characterized by persistent intrusive thoughts and repetitive ritualized behaviors. While gene variations, malfunction of cortico-striato-thalamo-cortical (CSTC) circuits, and dysregulated synaptic transmission have been implicated in the pathogenesis of OCD, the underlying mechanisms remain largely unknown. Here we show that OCD-like behavior in mice is caused by deficiency of SPRED2, a protein expressed in various brain regions and a potent inhibitor of Ras/ERK-MAPK signaling. Excessive self-grooming, reflecting OCD-like behavior in rodents, resulted in facial skin lesions in SPRED2 knockout (KO) mice. This was alleviated by treatment with the selective serotonin reuptake inhibitor fluoxetine. In addition to the previously suggested involvement of cortico-striatal circuits, electrophysiological measurements revealed altered transmission at thalamo-amygdala synapses and morphological differences in lateral amygdala neurons of SPRED2 KO mice. Changes in synaptic function were accompanied by dysregulated expression of various pre- and postsynaptic proteins in the amygdala. This was a result of altered gene transcription and triggered upstream by upregulated tropomyosin receptor kinase B (TrkB)/ERK-MAPK signaling in the amygdala of SPRED2 KO mice. Pathway overactivation was mediated by increased activity of TrkB, Ras, and ERK as a specific result of SPRED2 deficiency and not elicited by elevated brain-derived neurotrophic factor levels. Using the MEK inhibitor selumetinib, we suppressed TrkB/ERK-MAPK pathway activity in vivo and reduced OCD-like grooming in SPRED2 KO mice. Altogether, this study identifies SPRED2 as a promising new regulator, TrkB/ERK-MAPK signaling as a novel mediating mechanism, and thalamo-amygdala synapses as critical circuitry involved in the pathogenesis of OCD.
Abstract:We present a viable geometric solution for the detection of dynamic effects in complex networks. Building on Forman's discretization of the classical notion of Ricci curvature, we introduce a novel geometric method to characterize different types of real-world networks with an emphasis on peer-to-peer networks. We study the classical Ricci-flow in a network-theoretic setting and introduce an analytic tool for characterizing dynamic effects. The formalism suggests a computational method for change detection and the identification of fast evolving network regions and yields insights into topological properties and the structure of the underlying data.
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