129 research outputs found
Progressive Learning for Physics-informed Neural Motion Planning
Motion planning (MP) is one of the core robotics problems requiring fast
methods for finding a collision-free robot motion path connecting the given
start and goal states. Neural motion planners (NMPs) demonstrate fast
computational speed in finding path solutions but require a huge amount of
expert trajectories for learning, thus adding a significant training
computational load. In contrast, recent advancements have also led to a
physics-informed NMP approach that directly solves the Eikonal equation for
motion planning and does not require expert demonstrations for learning.
However, experiments show that the physics-informed NMP approach performs
poorly in complex environments and lacks scalability in multiple scenarios and
high-dimensional real robot settings. To overcome these limitations, this paper
presents a novel and tractable Eikonal equation formulation and introduces a
new progressive learning strategy to train neural networks without expert data
in complex, cluttered, multiple high-dimensional robot motion planning
scenarios. The results demonstrate that our method outperforms state-of-the-art
traditional MP, data-driven NMP, and physics-informed NMP methods by a
significant margin in terms of computational planning speed, path quality, and
success rates. We also show that our approach scales to multiple complex,
cluttered scenarios and the real robot set up in a narrow passage environment.
The proposed method's videos and code implementations are available at
https://github.com/ruiqini/P-NTFields.Comment: Accepted to Robotics: Science and Systems (RSS) 202
The gut microbiota, bile acids and their correlation in primary sclerosing cholangitis associated with inflammatory bowel disease.
BACKGROUND:
Patients with primary sclerosing cholangitis associated with inflammatory bowel disease (PSC-IBD) have a very high risk of developing colorectal neoplasia. Alterations in the gut microbiota and/or gut bile acids could account for the increase in this risk. However, no studies have yet investigated the net result of cholestasis and a potentially altered bile acid pool interacting with a dysbiotic gut flora in the inflamed colon of PSC-IBD.
AIM:
The aim of this study was to compare the gut microbiota and stool bile acid profiles, as well as and their correlation in patients with PSC-IBD and inflammatory bowel disease alone.
METHODS:
Thirty patients with extensive colitis (15 with concomitant primary sclerosing cholangitis) were prospectively recruited and fresh stool samples were collected. The microbiota composition in stool was profiled using bacterial 16S rRNA sequencing. Stool bile acids were assessed by high-performance liquid chromatography tandem mass spectrometry.
RESULTS:
The total stool bile acid pool was significantly reduced in PSC-IBD. Although no major differences were observed in the individual bile acid species in stool, their overall combination allowed a good separation between PSC-IBD and inflammatory bowel disease. Compared with inflammatory bowel disease alone, PSC-IBD patients demonstrated a different gut microbiota composition with enrichment in Ruminococcus and Fusobacterium genus compared with inflammatory bowel disease. At the operational taxonomic unit level major shifts were observed within the Firmicutes (73%) and Bacteroidetes phyla (17%). Specific microbiota-bile acid correlations were observed in PSC-IBD, where 12% of the operational taxonomic units strongly correlated with stool bile acids, compared with only 0.4% in non-PSC-IBD.
CONCLUSIONS:
Patients with PSC-IBD had distinct microbiota and microbiota-stool bile acid correlations as compared with inflammatory bowel disease. Whether these changes are associated with, or may predispose to, an increased risk of colorectal neoplasia needs to be further clarified.info:eu-repo/semantics/publishedVersio
Non-Hermitian topological exciton-polariton corner modes
We theoretically study two-dimensional exciton-polariton lattices and predict
that non-Hermitian topological corner modes can be formed under non-resonant
pumping. As a generalization of the non-Hermitian skin effect, all eigenstates
are localized at the two corners in our model. This is also a higher
dimensional topology compared to other proposals in exciton-polariton systems
and we find that it allows propagating signals in the bulk of the system to
travel around defects, which is not possible in one-dimensional topological
lattices or two-dimensional lattices with Hermitian edge states. Furthermore,
as all polariton states are localized away from an excitation spot, the system
offers an opportunity for more accurate measurement of the polariton-polariton
interaction strength as the pump-induced exciton-reservoir is spatially
separated from all polariton states
A systematic evaluation of network protection responses in future converter-dominated power systems
This paper illustrates how converter interfaces, used to connect renewable energy sources, HVDC links and infeeds to the power system, may bring significant changes to the behaviour of protection systems in the future. A converter model, capable of providing adjustable fault responses, is used to investigate the response of power system protection to a range of fault conditions. Different scenarios have been simulated by applying different types of faults at different location of the transmission system with a variety of different converter response types. A dynamic, verified, relay model and a hardware relay device have been injected with the simulated results to ascertain network protection performance
Spin-polarized antichiral exciton-polariton edge states
We consider theoretically a system of exciton-polariton micropillars arranged
in a honeycomb lattice. The naturally present TE-TM splitting and an
alternating Zeeman splitting, where the different sublattices experience
opposite Zeeman splitting, shifts the Dirac points in energy, giving rise to
antichiral behavior. In a strip geometry having zigzag edges, two pairs of edge
states exist and propagate in the same direction (including the states at the
opposite edges). The edge modes localized at the opposite edges have opposite
spins (circular polarizations), which leads to co-propagating "+-" spin
channels. The antichiral edge states are protected by non-zero winding numbers
and can propagate around a 60 degree bend without being reflected. We further
compare the transport properties of these edge states with chiral edge modes
and propose a scheme to realize them experimentally
Local dominance unveils clusters in networks
Clusters or communities can provide a coarse-grained description of complex
systems at multiple scales, but their detection remains challenging in
practice. Community detection methods often define communities as dense
subgraphs, or subgraphs with few connections in-between, via concepts such as
the cut, conductance, or modularity. Here we consider another perspective built
on the notion of local dominance, where low-degree nodes are assigned to the
basin of influence of high-degree nodes, and design an efficient algorithm
based on local information. Local dominance gives rises to community centers,
and uncovers local hierarchies in the network. Community centers have a larger
degree than their neighbors and are sufficiently distant from other centers.
The strength of our framework is demonstrated on synthesized and empirical
networks with ground-truth community labels. The notion of local dominance and
the associated asymmetric relations between nodes are not restricted to
community detection, and can be utilised in clustering problems, as we
illustrate on networks derived from vector data
Mortality, outcomes, costs, and use of medicines following a first heart failure hospitalization: EVOLUTION HF
Background:
There are few contemporary data on outcomes, costs, and treatment following a hospitalization for heart failure (hHF) in epidemiologically representative cohorts.
Objectives:
The study sought to describe rehospitalizations, hospitalization costs, use of guideline-directed medical therapy (GDMT) (renin-angiotensin system inhibitors, sacubitril/valsartan, beta-blockers, mineralocorticoid receptor antagonists, and sodium-glucose cotransporter-2 inhibitors), and mortality after hHF.
Methods:
EVOLUTION HF (Utilization of Dapagliflozin and Other Guideline Directed Medical Therapies in Heart Failure Patients: A Multinational Observational Study Based on Secondary Data) is an observational, longitudinal cohort study using data from electronic health records or claims data sources in Japan, Sweden, the United Kingdom, and the United States. Adults with a first hHF discharge between 2018 and 2022 were included. One-year event rates per 100 patient-years (ERs) for death and rehospitalizations (with a primary diagnosis of heart failure (HF), chronic kidney disease [CKD], myocardial infarction, stroke, or peripheral artery disease) were calculated. Hospital health care costs were cumulatively summarized. Cumulative GDMT use was assessed using Kaplan-Meier estimates.
Results:
Of 263,525 patients, 28% died within the first year post-hHF (ER: 28.4 [95% CI: 27.0-29.9]). Rehospitalizations were mainly driven by HF (ER: 13.6 [95% CI: 9.8-17.4]) and CKD (ER: 4.5 [95% CI: 3.6-5.3]), whereas the ERs for myocardial infarction, stroke, and peripheral artery disease were lower. Health care costs were predominantly driven by HF and CKD. Between 2020 and 2022, use of renin-angiotensin system inhibitors, sacubitril/valsartan, beta-blockers, and mineralocorticoid receptor antagonists changed little, whereas uptake of sodium-glucose cotransporter-2 inhibitors increased 2- to 7-fold.
Conclusions:
Incident post-hHF rehospitalization risks and costs were high, and GDMT use changed little in the year following discharge, highlighting the need to consider earlier and greater implementation of GDMT to manage risks and reduce costs
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IFNγ-Dependent Tissue-Immune Homeostasis Is Co-opted in the Tumor Microenvironment
Homeostatic programs balance immune protection and self-tolerance. Such mechanisms likely impact autoimmunity and tumor formation, respectively. How homeostasis is maintained and impacts tumor surveillance is unknown. Here, we find that different immune mononuclear phagocytes share a conserved steady-state program during differentiation and entry into healthy tissue. IFNγ is necessary and sufficient to induce this program, revealing a key instructive role. Remarkably, homeostatic and IFNγ-dependent programs enrich across primary human tumors, including melanoma, and stratify survival. Single-cell RNA sequencing (RNA-seq) reveals enrichment of homeostatic modules in monocytes and DCs from human metastatic melanoma. Suppressor-of-cytokine-2 (SOCS2) protein, a conserved program transcript, is expressed by mononuclear phagocytes infiltrating primary melanoma and is induced by IFNγ. SOCS2 limits adaptive anti-tumoral immunity and DC-based priming of T cells in vivo, indicating a critical regulatory role. These findings link immune homeostasis to key determinants of anti-tumoral immunity and escape, revealing co-opting of tissue-specific immune development in the tumor microenvironment. Keywords: dendritic cells; homeostasis; differentiation; IFNγ; tumor microenvironment; melanoma tolerance; immunotherapy; suppressor-of-cytokine-signaling 2 (SOCS2); tissue mononuclear phagocyte
Correction:Association of low-frequency and rare coding variants with information processing speed
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