200 research outputs found
Feature Mixing for Writer Retrieval and Identification on Papyri Fragments
This paper proposes a deep-learning-based approach to writer retrieval and
identification for papyri, with a focus on identifying fragments associated
with a specific writer and those corresponding to the same image. We present a
novel neural network architecture that combines a residual backbone with a
feature mixing stage to improve retrieval performance, and the final descriptor
is derived from a projection layer. The methodology is evaluated on two
benchmarks: PapyRow, where we achieve a mAP of 26.6 % and 24.9 % on writer and
page retrieval, and HisFragIR20, showing state-of-the-art performance (44.0 %
and 29.3 % mAP). Furthermore, our network has an accuracy of 28.7 % for writer
identification. Additionally, we conduct experiments on the influence of two
binarization techniques on fragments and show that binarizing does not enhance
performance. Our code and models are available to the community.Comment: accepted for HIP@ICDAR202
Gait learning for soft microrobots controlled by light fields
Soft microrobots based on photoresponsive materials and controlled by light
fields can generate a variety of different gaits. This inherent flexibility can
be exploited to maximize their locomotion performance in a given environment
and used to adapt them to changing conditions. Albeit, because of the lack of
accurate locomotion models, and given the intrinsic variability among
microrobots, analytical control design is not possible. Common data-driven
approaches, on the other hand, require running prohibitive numbers of
experiments and lead to very sample-specific results. Here we propose a
probabilistic learning approach for light-controlled soft microrobots based on
Bayesian Optimization (BO) and Gaussian Processes (GPs). The proposed approach
results in a learning scheme that is data-efficient, enabling gait optimization
with a limited experimental budget, and robust against differences among
microrobot samples. These features are obtained by designing the learning
scheme through the comparison of different GP priors and BO settings on a
semi-synthetic data set. The developed learning scheme is validated in
microrobot experiments, resulting in a 115% improvement in a microrobot's
locomotion performance with an experimental budget of only 20 tests. These
encouraging results lead the way toward self-adaptive microrobotic systems
based on light-controlled soft microrobots and probabilistic learning control.Comment: 8 pages, 7 figures, to appear in the proceedings of the IEEE/RSJ
International Conference on Intelligent Robots and Systems 201
Electrochromic Polymer Ink Derived from a Sidechain-Modified EDOT for Electrochromic Devices with Colorless Bright State
AbstractPrintable organic electrochromic materials are the key component of flexible low power and low weight displays and dynamic shading systems. A vast number of more or less wellâperforming materials is reported in the literature, but only a very limited number of them have been tested in an industriallyârelevant environment so far. Upscaling requires simplicity of synthesis, overall sustainability, low cost and compatibility with simple and high throughput wetâchemical deposition techniques, such as slotâdie coating or inkjet printing. In the present paper, an original process is described that enables the controlled oxidative polymerization of a water insoluble, functionalized 3,4âethylene dioxythiophene (EDOT) derivative. This process leads to the formation of an ink that consists solely of active polymeric material (no dispersing agents) and has suitable rheological properties for use in rollâtoâroll slotâdie coating or inkâjet printing. The straightforward deposition, followed by a simple thermal treatment, directly yields stable and homogeneous thin films with stateâofâtheâart electrochromic performance
CLIO: a Novel Robotic Solution for Exploration and Rescue Missions in Hostile Mountain Environments
Rescue missions in mountain environments are hardly achievable by standard
legged robots - because of the high slopes - or by flying robots - because of
limited payload capacity. We present a novel concept for a rope-aided climbing
robot, which can negotiate up-to-vertical slopes and carry heavy payloads. The
robot is attached to the mountain through a rope, and is equipped with a leg to
push against the mountain and initiate jumping maneuvers. Between jumps, a
hoist is used to wind/unwind the rope to move vertically and affect the lateral
motion. This simple (yet effective) two-fold actuation allows the system to
achieve high safety and energy efficiency. Indeed, the rope prevents the robot
from falling, while compensating for most of its weight, drastically reducing
the effort required by the leg actuator. We also present an optimal control
strategy to generate point-to-point trajectories overcoming an obstacle. We
achieve fast computation time (1 s) thanks to the use of a custom simplified
robot model. We validated the generated optimal movements in Gazebo simulations
with a complete robot model, showing the effectiveness of the proposed
approach, and confirming the interest of our concept. Finally, we performed a
reachability analysis showing that the region of achievable targets is strongly
affected by the friction properties of the foot-wall contact.Comment: 6 page
Selective maintenance of Drosophila tandemly arranged duplicated genes during evolution
Genes occurring in conserved, tandemly-arrayed clusters in Drosophila melanogaster are co-expressed to a much higher extent than other duplicated genes
New discoveries at Woolsey Mound, MC118, northern Gulf of Mexico
Woolsey Mound, a 1km-diameter carbonate-gas hydrate complex in the northern Gulf of Mexico, is the site of the Gulfâs only seafloor monitoring station-observatory in its only research reserve, Mississippi Canyon 118. Active venting, outcropping hydrate, and a thriving chemosynthetic community recommend the site for study. Since 2005, the Gulf of Mexico Hydrates Research Consortium has been conducting multidisciplinary studies to 1. Characterize the site, 2. Establish a facility for real-time monitoring-observing of gas hydrates in a natural setting, 3. Study the effects of gas hydrates on seafloor stability, 4. Establish fluid migration routes and estimates of fluid-flux at the site, 5. Establish the interrelationships between the
organisms at the vent site and the association-dissociation of hydrates. A variety of novel geological, geophysical, geochemical and biological studies has been designed and
conducted, some in survey mode, others in monitoring mode. Geophysical studies involving merging multiple seismic data acquisition systems accompanied by the application of custom processing techniques verify communication of surface features with deep structures. Supporting geological data derive from innovative recovery techniques. Geochemical sensors, used experimentally in survey mode, including aboard an AUV, double as monitoring devices. A suite of pore-fluid sampling devices has returned data that capture change at the site in daily increments; using only noise as an energy source, hydrophones have
returned daily fluctuations in physical properties. Ever-expanding capabilities of a custom-ROV have been determined by research needs. Processing of new as well as conventional data via unconventional means
has resulted in the discovery of new featuresâŠ..vents, faults, benthic faunaâŠ..and modification of others including pockmarks, hydrate outcrops, vent activity, and water-column chemical plumes.
Though real-time monitoring awaits communications and power link to land, periodic data-collection reveals a carbonate-hydrate mound, part of an immensely complex hydrocarbon system
New RollâtoâRoll Processable PEDOTâBased Polymer with Colorless Bleached State for Flexible Electrochromic Devices
Conjugated electrochromic (EC) polymers for flexible EC devices (ECDs) generally lack a fully colorless bleached state. A strategy to overcome this drawback is the implementation of a new sidechain-modified poly(3,4-ethylene dioxythiophene) derivative that can be deposited in thin-film form in a customized high-throughput and large-area roll-to-roll polymerization process. The sidechain modification provides enhanced EC properties in terms of visible light transmittance change, ÎÏv = 59% (ÎL* = 54.1), contrast ratio (CR = 15.8), coloration efficiency (η = 530 cmÂČ Câ1), and color neutrality (L* = 83.8, a* = â4.3, b* = â4.1) in the bleached state. The intense blue-colored polymer thin films exhibit high cycle stability (10 000 cycles) and fast response times. The design, synthesis, and polymerization of the modified 3,4-ethylene dioxythiophene derivative are discussed along with a detailed optical, electrochemical, and spectroelectrochemical characterization of the resulting EC thin films. Finally, a flexible see-through ECD with a visible light transmittance change of ÎÏv = 47% (ÎL* = 51.9) and a neutral-colored bleached state is developed
A new structural class of serine protease inhibitors revealed by the structure of the hirustasinâkallikrein complex
AbstractBackground: Hirustasin belongs to a class of serine protease inhibitors characterized by a well conserved pattern of cysteine residues. Unlike the closely related inhibitors, antistasin/ghilanten and guamerin, which are selective for coagulation factor Xa or neutrophil elastase, hirustasin binds specifically to tissue kallikrein. The conservation of the pattern of cysteine residues and the significant sequence homology suggest that these related inhibitors possess a similar three-dimensional structure to hirustasin.Results: The crystal structure of the complex between tissue kallikrein and hirustasin was analyzed at 2.4 Ă
resolution. Hirustasin folds into a brick-like structure that is dominated by five disulfide bridges and is sparse in secondary structural elements. The cysteine residues are connected in an abab cdecde pattern that causes the polypeptide chain to fold into two similar motifs. As a hydrophobic core is absent from hirustasin the disulfide bridges maintain the tertiary structure and present the primary binding loop to the active site of the protease. The general structural topography and disulfide connectivity of hirustasin has not previously been described.Conclusions: The crystal structure of the kallikreinâhirustasin complex reveals that hirustasin differs from other serine protease inhibitors in its conformation and its disulfide bond connectivity, making it the prototype for a new class of inhibitor. The disulfide pattern shows that the structure consists of two domains, but only the C-terminal domain interacts with the protease. The disulfide pattern of the N-terminal domain is related to the pattern found in other proteins. Kallikrein recognizes hirustasin by the formation of an antiparallel ÎČ sheet between the protease and the inhibitor. The P1 arginine binds in a deep negatively charged pocket of the enzyme. An additional pocket at the periphery of the active site accommodates the sidechain of the P4 valine
Clinical insights into traumatic injury of the inferior alveolar and lingual nerves: a comprehensive approach from diagnosis to therapeutic interventions
Objectives
This scoping review explores the risk and management of traumatic injuries to the inferior alveolar and lingual nerves during mandibular dental procedures. Emphasizing the significance of diagnostic tools, the review amalgamates existing knowledge to offer a comprehensive overview.
Materials and methods
A literature search across PubMed, Embase, and Cochrane Library informed the analysis.
Results
Traumatic injuries often lead to hypo-/anesthesia and neuropathic pain, impacting individuals psychologically and socially. Diagnosis involves thorough anamnesis, clinical-neurological evaluations, and radiographic imaging. Severity varies, allowing for conservative or surgical interventions. Immediate action is recommended for reversible causes, while surgical therapies like decompression, readaptation, or reconstruction yield favorable outcomes. Conservative management, utilizing topical anesthesia, capsaicin, and systemic medications (tricyclic antidepressants, antipsychotics, and serotonin-norepinephrine-reuptake-inhibitors), proves effective for neuropathic pain.
Conclusions
Traumatic nerve injuries, though common in dental surgery, often go unrecorded. Despite lacking a definitive diagnostic gold standard, a meticulous examination of the injury and subsequent impairments is crucial.
Clinical relevance
Tailoring treatment to each case's characteristics is essential, recognizing the absence of a universal solution. This approach aims to optimize outcomes, restore functionality, and improve the quality of life for affected individuals
Clinical correlations to distinguish severe from milder forms of obstructive sleep apnoea syndrome using overnight oximetry for prioritising adenotonsillectomy in a limited-resource setting
BACKGROUND : In resource-poor settings with limited surgical services, it is essential to identify and prioritise children with severe and very severe obstructive sleep apnoea syndrome (OSAS) to expedite surgery. McGill's Oximetry Score (MOS) has been validated against polysomnography for OSAS and is affordable and easy to use.
AIMS : The aim of this study was to assess the correlation of tonsillar size and clinical symptoms with MOS grade 3 or 4, to identify who requires overnight oximetry and who to prioritise for adenotonsillectomy.
METHODS : Children with suspected OSAS were recruited from the otolaryngology clinic at the Red Cross War Memorial Children's Hospital. Demographics, symptom screening scores (SSS), patient characteristics, overnight oximetry (OO), echocardiography and MOS scores (graded 1â4) were recorded. Multivariate modified-Poisson regression models were used to examine correlations of patient characteristics âwith grade 3 or 4 MOS.
RESULTS : One-hundred-and-three children were analysed, 38% were female, and median (IQR) age was 3.8 (2.5â5.3) years. Increased tonsil size was associated with a 60% increased risk of grade 3 or 4 MOS, risk ratio (RR) 1.59, 95% CI 1.10â2.29 (p = 0.014). Children with witnessed apnoeic events during sleep had 1.3 times increased risk of MOS Grade 3 or 4, RR 1.31, 95% CI (p = 0.033). A significant correlation was shown with grade 3 or 4 MOS, RR 1.15, 95% CI 1.03â1.27 (p = 0.010) by combining tonsillar size with the following symptoms: apnoeic events; struggling to breathe during sleep and needing to stimulate the child to breathe.
CONCLUSION : Identifying children with suspected OSAS who require overnight oximetry can be performed using a simple 3-question screening tool: witnessed apnoeic events, struggling to breathe and the need to shake them awake to breathe. This is more precise with an additional clinical finding of grade 3 or 4 tonsils. These children should have surgery expedited. Any child with a MOS 3 or 4 score on OO needs to have expedited surgery.https://www.elsevier.com/locate/ijporlhj2023School of Health Systems and Public Health (SHSPH
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