124 research outputs found
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Regulation of Behavioral Arousal in C. elegans
Animals undergo periods of behavioral quiescence and arousal in response to environmental, circadian, or developmental cues. During larval molts, C. elegans undergoes a period of profound behavioral quiescence termed lethargus. Locomotion quiescence during lethargus was abolished in mutants lacking a neuropeptide receptor (NPR-1), and was reduced in mutants lacking NPR-1 ligands (FLP-18 and -21). Wild type strains are polymorphic for the npr-1 gene, and their lethargus behavior varies correspondingly. Locomotion quiescence and arousal were mediated by decreased and increased secretion of an arousal neuropeptide (PDF-1) from central neurons. PDF receptors (PDFR-1) expressed in peripheral mechanosensory neurons enhanced touch-evoked calcium transients. Thus, a central circuit stimulates arousal from lethargus by enhancing the sensitivity of peripheral mechanosensory neurons in the body. These results define a circuit mechanism controlling a developmentally programmed form of quiescence
Efficient Graduated Non-Convexity for Pose Graph Optimization
We propose a novel approach to Graduated Non-Convexity (GNC) and demonstrate
its efficacy through its application in robust pose graph optimization, a key
component in SLAM backends. Traditional GNC methods often rely on heuristic
methods for GNC schedule, updating control parameter {\mu} for escalating the
non-convexity. In contrast, our approach leverages the properties of convex
functions and convex optimization to identify the boundary points beyond which
convexity is no longer guaranteed, thereby eliminating redundant optimization
steps in existing methodologies and enhancing both speed and robustness. We
show that our method outperforms the state-of-the-art method in terms of speed
and accuracy when used for robust back-end pose graph optimization via GNC. Our
work builds upon and enhances the open-source riSAM framework. Our
implementation can be accessed from: https://github.com/SNU-DLLAB/EGNC-PGOComment: 6 pages, 6 figure
Adaptive Graduated Non-Convexity for Pose Graph Optimization
We present a novel approach to robust pose graph optimization based on
Graduated Non-Convexity (GNC). Unlike traditional GNC-based methods, the
proposed approach employs an adaptive shape function using B-spline to optimize
the shape of the robust kernel. This aims to reduce GNC iterations, boosting
computational speed without compromising accuracy. When integrated with the
open-source riSAM algorithm, the method demonstrates enhanced efficiency across
diverse datasets. Accompanying open-source code aims to encourage further
research in this area. https://github.com/SNU-DLLAB/AGNC-PGOComment: 4 pages, 3 figures. Accepted for the workshop on Robotic Perception
and Mapping(ROPEM): Frontier Vision & Learning Techniques, organized at the
2023 International Conference on Intelligent Robots and Systems (IROS
CLARA: Classifying and Disambiguating User Commands for Reliable Interactive Robotic Agents
In this paper, we focus on inferring whether the given user command is clear,
ambiguous, or infeasible in the context of interactive robotic agents utilizing
large language models (LLMs). To tackle this problem, we first present an
uncertainty estimation method for LLMs to classify whether the command is
certain (i.e., clear) or not (i.e., ambiguous or infeasible). Once the command
is classified as uncertain, we further distinguish it between ambiguous or
infeasible commands leveraging LLMs with situational aware context in a
zero-shot manner. For ambiguous commands, we disambiguate the command by
interacting with users via question generation with LLMs. We believe that
proper recognition of the given commands could lead to a decrease in
malfunction and undesired actions of the robot, enhancing the reliability of
interactive robot agents. We present a dataset for robotic situational
awareness, consisting pair of high-level commands, scene descriptions, and
labels of command type (i.e., clear, ambiguous, or infeasible). We validate the
proposed method on the collected dataset, pick-and-place tabletop simulation.
Finally, we demonstrate the proposed approach in real-world human-robot
interaction experiments, i.e., handover scenarios
Targeting Myocardial Equilibrative Nucleoside Transporter ENT1 Provides Cardioprotection by Enhancing Myeloid Adora2b Signaling.
Previous studies implicate extracellular adenosine signaling in attenuating myocardial ischemia and reperfusion injury (IRI). This extracellular adenosine signaling is terminated by its uptake into cells by equilibrative nucleoside transporters (ENTs). Thus, we hypothesized that targeting ENTs would function to increase cardiac adenosine signaling and concomitant cardioprotection against IRI. Mice were exposed to myocardial ischemia and reperfusion injury. Myocardial injury was attenuated in mice treated with the nonspecific ENT inhibitor dipyridamole. A comparison of mice with global Ent1 or Ent2 deletion showed cardioprotection only in Ent1-/- mice. Moreover, studies with tissue-specific Ent deletion revealed that mice with myocyte-specific Ent1 deletion (Ent1loxP/loxP Myosin Cre+ mice) experienced smaller infarct sizes. Measurements of cardiac adenosine levels demonstrated that postischemic elevations of adenosine persisted during reperfusion after targeting ENTs. Finally, studies in mice with global or myeloid-specific deletion of the Adora2b adenosine receptor (Adora2bloxP/loxP LysM Cre+ mice) implied that Adora2b signaling on myeloid-inflammatory cells in cardioprotection provided by ENT inhibition. These studies reveal a previously unrecognized role for myocyte-specific ENT1 in cardioprotection by enhancing myeloid-dependent Adora2b signaling during reperfusion. Extension of these findings implicates adenosine transporter inhibitors in cardioprotection against ischemia and reperfusion injury
The Sedimentary records of the Hapcheon impact crater basin in Korea over the past 1.3 Ma
The Hapcheon impact crater is the only meteorite impact crater identified on the Korean peninsula. However, the morphology of the impact crater and the nature of the meteorite collision are unknown. In this study, we analyzed the sedimentary facies using grain size data; computed tomography images, 14C, 10Be, and optically stimulated luminescence dating on a >66-m-long sediment core (20HCL04) recovered from the Hapcheon Basin. Four sedimentary units and 10 types of facies were documented in the Hapcheon Basin sediment core. The sedimentary units comprise 1) a lower part (unit 1) that is dominated by moderately to well-sorted coarse gravel, which contains some impact-related sediments; 2) a middle part (units 2 and 3) dominated by well-laminated mud; and 3) an upper part (Unit 4) that is dominated by poorly sorted coarse gravel supplied from the surrounding mountain slopes by alluvial and fluvial processes. After the meteorite impact, the Hapcheon impact crater was filled with deposits from the crater wall after ca. 1.3 Ma and the Hapcheon Basin became a deep lake environment. After ca. 0.5 Ma, sediments were supplied from the surrounding mountains until the lake was filled. Finally, sediments were deposited in an alluvial fan setting. In addition, the Hapcheon Basin sedimentary cores contain a tephra layer and deformed soft sediments that can be used to investigate volcanic and seismic events on the Korean Peninsula over the past 1.3 Ma
Two-loop Barr-Zee type Contributions to in the MSSM
We consider the contribution of a two-loop Barr-Zee type diagram to
in the minimal supersymmetric standard model (MSSM). At relatively
large , we show that the contribution of light third generation
scalar fermions and neutral CP-even Higgs, , can easily explain the
very recent BNL experimental data. In our analysis prefers negative
and positive . It is more sensitive to the chirality flipping
h^0(H^0)\wt{f}_R^*\wt{f}_L rather than chirality conserving couplings.Comment: 10 pages, 5 figures, references adde
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