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53 posts48 participants4 posts today
"Divisible and indivisible Stochastic-Quantum dynamics"
https://arxiv.org/abs/2505.08785 #Physics.Data-An #Quant-Ph #Dynamics #Matrix
arXiv.orgDivisible and indivisible Stochastic-Quantum dynamicsThis work presents a complete geometrical characterisation of divisible and indivisible time-evolution at the level of probabilities for systems with two configurations, open or closed. Our new geometrical construction in the space of stochastic matrices shows the existence of conical bounds separating divisible and indivisible dynamics, bearing analogy with the relativistic causal structure, with an emerging time pointing towards information erasure when the dynamics are divisible. Indivisible dynamics, which include quantum dynamics, are characterised by a time-flow against the information-erasure time coordinate or by being tachyonic with respect to the cones in the stochastic matrix space. This provides a geometric counterpart of other results in the literature, such as the equivalence between information-decreasing and divisible processes. The results apply under minimal assumptions: (i) the system has two configurations, (ii) one can freely ascribe initial probabilities to both and (iii) probabilities at other times are linearly related to the initial ones through conditional probabilities. The optional assumption of (iv) continuity places further constraints on the system, removing one of the past cones. Discontinuous stochastic dynamics in continuous time include cases with divisible blocks of evolution which are not themselves divisible. We show that the connection between continuity and multiplicity of divisors holds for any dimension. We extend methods of coarse graining and dilations by incorporating dynamics and uncertainty, connecting them with divisibility criteria. This is a first step towards a full geometric characterisation of indivisible stochastic dynamics for any number of configurations which, as they cannot at the level of probabilities be reduced to a composition of evolution operators, constitute fundamental elements of probabilistic time-evolution.
"$\mathcal{H}$-HIGNN: A Scalable Graph Neural Network Framework with Hierarchical Matrix Acceleration for Simulation of Large-Scale Particulate Suspensions"
https://arxiv.org/abs/2505.08174 #Physics.Comp-Ph #Forces #Matrix
arXiv.org$\mathcal{H}$-HIGNN: A Scalable Graph Neural Network Framework with Hierarchical Matrix Acceleration for Simulation of Large-Scale Particulate SuspensionsWe present a fast and scalable framework, leveraging graph neural networks (GNNs) and hierarchical matrix ($\mathcal{H}$-matrix) techniques, for simulating large-scale particulate suspensions, which have broader impacts across science and engineering. The framework draws on the Hydrodynamic Interaction Graph Neural Network (HIGNN) that employs GNNs to model the mobility tensor governing particle motion under hydrodynamic interactions (HIs) and external forces. HIGNN offers several advantages: it effectively captures both short- and long-range HIs and their many-body nature; it realizes a substantial speedup over traditional methodologies, by requiring only a forward pass through its neural networks at each time step; it provides explainability beyond black-box neural network models, through direct correspondence between graph connectivity and physical interactions; and it demonstrates transferability across different systems, irrespective of particles' number, concentration, configuration, or external forces. While HIGNN provides significant speedup, the quadratic scaling of its overall prediction cost (with respect to the total number of particles), due to intrinsically slow-decaying two-body HIs, limits its scalability. To achieve superior efficiency across all scales, in the present work we integrate $\mathcal{H}$-matrix techniques into HIGNN, reducing the prediction cost scaling to quasi-linear. Through comprehensive evaluations, we validate $\mathcal{H}$-HIGNN's accuracy, and demonstrate its quasi-linear scalability and superior computational efficiency. It requires only minimal computing resources; for example, a single mid-range GPU is sufficient for a system containing 10 million particles. Finally, we demonstrate $\mathcal{H}$-HIGNN's ability to efficiently simulate practically relevant large-scale suspensions of both particles and flexible filaments.
La filosofía de #Matrix que en muchos aspectos es un buen reflejo de nuestra actual sociedad adormecida o fanatizada, en la ignorancia, para el mayor CONTROL 
Matrix - La ignorancia es la felicidad
AI killed the 1337 coders 
https://anonsys.net/display/bf69967c-1968-236c-9c28-3d4933012748
"Mechanical forces drive mitochondrial matrix extrusion and apoptotic pore growth"
https://www.biorxiv.org/content/10.1101/2025.05.12.653510v1?rss=1 #Mechanical #Matrix #Cell
Les alternatives libres à Discord
freue mich sehr auf den #Digitaltag in @freiburg am freitag mit @evawolfangel als speakerin
und @dejan in der barcamp moderation
unser beitrag zu security dreht sich diesmal um @matrix und @element
@wir legen live accounts an und chatten los #datasovereignty #matrix #barcamp
"This week in KDE Apps" brings optimizations galore!
Look out for boosts to @Krita's text rendering, improvements to @kdenlive's online resource and audio thumbnail rendering, Qrca's better battery usage, reduced memory usage in @neochat, and more.
https://blogs.kde.org/2025/05/12/this-week-in-kde-apps/
#apps #FreeSoftware #OpenSource #videoediting #design #matrix
"A comprehensive protocol for PDMS fabrication for use in cell culture"
https://doi.org/doi:10.1371/journal.pone.0323283
https://pubmed.ncbi.nlm.nih.gov/40354467/
#Mechanical #Matrix #Cell
doi.orgA comprehensive protocol for PDMS fabrication for use in cell cultureCells exhibit remarkable sensitivity to the mechanical properties of their surrounding matrix, particularly stiffness changes, a phenomenon known as cellular mechanotransduction. In vivo, tissues exhibit a wide range of stiffness, from kilopascals (kPa) to megapascals (MPa), which can alter with aging and disease. Traditional cell culture methods employ plastic substrates with stiffness in the gigapascal range, which does not accurately mimic the physiological conditions of most biological tissues. Therefore, employing substrates that can be engineered to span a wide range of stiffnesses, closely resembling the native tissue environment, is crucial for obtaining results that more accurately reflect cellular responses in vivo. Polydimethylsiloxane (PDMS) substrates are widely used in cell culture for their ability to simulate tissue stiffness, but their optimization presents several challenges. Fabrication requires precise control over mixing, weighing, and curing to ensure reproducible mechanical properties. Inconsistent preparation can lead to improperly cured PDMS substrates, compromising experimental outcomes. Additionally, PDMS’s inherent hydrophobicity poses challenges for cell attachment, necessitating surface modifications to enhance adhesion. Moreover, the risk of contamination during the sterilization process necessitates stringent protocols to maintain cell culture integrity. These challenges are further compounded by substrate autofluorescence which can cause difficulties when imaging cells. The aim of this study is to develop a standardized method for fabricating PDMS substrates with tuneable stiffness, ranging from kPa to MPa, suitable for diverse cell types using standard laboratory equipment. This method aims to minimize the complexity and equipment required for PDMS fabrication, ensuring reproducibility and ease of use. Achieving consistent and contaminant-free PDMS substrates will facilitate a broader adoption of these substrates in mechanobiology research and improve the relevance of in vitro models to in vivo conditions. Ultimately, contributing to a more comprehensive understanding of cellular responses to mechanical cues in health and disease.
Goddamn! My Conduit server's registration was open, and now my server is banned by many, many Matrix servers because I had 232 spam accounts posting spam originating from my server. Well deserved, I guess.
Any hints on how to get unbanned? I already contacted moderation:gnome.org as this was the server where I noticed the ban. But my logs are full of servers refusing to federate. I guess there's a blocklist involved somewhere. Any hints?
Managing a Public End to End Room on Matrix: Lessons Learned
https://gadgetbridge.org/blog/managing-a-public-end-to-end-room-on-matrix-lessons-learned/
gadgetbridge.orgManaging a Public End to End Room on Matrix: Lessons Learned - GadgetbridgeA free and open source Android application for bluetooth devices.
Continued thread
#ThreemaApp für echte #Privatsphäre & #Datenschutz
Siehe
SecureMessagingApps.com
bewerte
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86 #Threema = sicherster #Messenger
81 #SimpleXChat
77 #Signal
77 #Session
68 #Wire
61 #Wickr #Amazon
56 #Element / #Matrix
37 #Apple #iMessage
32 #WhatsApp
27 #Telegram
26 #Facebook Mess.
Bluesky SocialBluesky
"Hyperbolic and Elliptic Points Tracking Algorithm (HEPTA) in two-dimensional non-stationary velocity fields defined on a discrete grid"
https://arxiv.org/abs/2505.05975 #Physics.Ao-Ph #Dynamics #Matrix
arXiv.orgHyperbolic and Elliptic Points Tracking Algorithm (HEPTA) in two-dimensional non-stationary velocity fields defined on a discrete gridThis article presents a new algorithm, the Hyperbolic and Elliptic Points Tracking Algorithm (HEPTA), designed for automated tracking of elliptic and hyperbolic stationary points in two-dimensional non-stationary velocity fields defined on a discrete grid. HEPTA analyzes the stability, bifurcations, and Lagrangian dynamics of stationary points. By leveraging bilinear interpolation, Jacobian matrix analysis, and trajectory tracking, the algorithm accurately identifies the locations of vortex centers (elliptic points) and strain zones (hyperbolic points). A methodology has been developed to address bifurcation events and transitions across grid cell boundaries that occur during the evolution of stationary points in a discrete velocity field. The algorithm was tested on AVISO satellite altimetry data in the Kuroshio Current region, which is characterized by intense eddy formation. These data represent a two-dimensional discrete velocity field with a daily time step. The results show that HEPTA accurately identifies and tracks both cyclonic and anticyclonic eddies, even under conditions of rapid eddy drift and complex hydrodynamic conditions. This study provides a reliable and efficient tool for analyzing the dynamics of mesoscale formations, which may be useful in oceanographic research, climate modeling, and operational oceanography.
"Indirect Influence on Network Diffusion"
https://arxiv.org/abs/2505.05931 #Cond-Mat.Stat-Mech #Physics.Soc-Ph #Dynamics #Matrix
arXiv.orgIndirect Influence on Network DiffusionModels of network diffusion typically rely on the Laplacian matrix, capturing interactions via direct connections. Beyond direct interactions, information in many systems can also flow via indirect pathways, where influence typically diminishes over distance. In this work, we analyze diffusion dynamics incorporating such indirect connections using the $d$-path Laplacian framework. We introduce a parameter, the indirect influence, based on the change in the second smallest eigenvalue of the generalized path Laplacian, to quantify the impact of these pathways on diffusion timescales relative to direct-only models. Using perturbation theory and mean-field approximations, we derive analytical expressions for the indirect influence in terms of structural properties of random networks. Theoretical predictions align well with numerical simulations, providing a phase diagram for when indirect influence becomes significant. We also identify a structural phase transition governed by the emergence of $d$-paths and derive the critical connection probability above which they dramatically alter diffusion. This study provides a quantitative understanding of how indirect pathways shape network dynamics and reveals their collective structural onset.
"Mesenchymal Stromal Cell Chondrogenic Differentiation Induced by Continuous Stiffness Gradient in Photocrosslinkable Hydrogels"
https://doi.org/doi:10.1002/jbm.a.37928
https://pubmed.ncbi.nlm.nih.gov/40349364/
#Mechanical #Matrix #Cell
Illustration depicting the current state of my professional carreer… Slightly stuck.
