Map Location Research Articles

Novel and classical methods similarly describe variation in territory size among males in Neotropical poison frogs with contrasting reproductive and behavioral strategies

AbstractTerritoriality is a form of social dominance concerning the use of space that ensures the territory owner primary access to critical resources. The territory is defended with visual displays, advertisement calls, physical attacks, or chemical signals. The territory is frequently estimated by mapping locations where an animal is observed engaging in territorial behavior or by tracking. However, these approaches may over- or underestimate the areas defended. Thus, the use of approaches explicitly determining defended areas is critical to properly characterize the territory. Intrusion experiments can elicit a response in territory holders, allowing one to characterize their aggressive responses; however, the aggressive response depends on the species. We describe an approach to experimentally estimate the territory size using playback experiments in a species that exhibits a stereotypical phonotactic response: the nurse frog, Allobates aff. trilineatus and develop a new behavioral index that allows assessing territory size in response to playbacks for a species with non-stereotyped phonotactic response: the endangered Lehmann’s poison frog, Oophaga lehmanni. We conducted 772 playback experiments on 18 males of A. aff. trilineatus, and 222 on nine males of O. lehmanni. We analyzed the results of playback experiments with three different area estimators regularly used to estimate space use and evaluated whether these estimates are correlated. The shape and size of territories varied among individuals and estimators in both species. Although we found that the absolute size of the territory depends on the method used, estimates were strongly correlated, meaning that different estimators similarly describe variation in territory size among males. Choosing an analysis method may not be particularly important for studying the characteristics of territoriality over space and time but using a systematic and standardized experimental approach that also incorporates the particularities of the aggressive response of each species is essential to understand the evolution of space use by poison frogs and other territorial species.

Guided-attention and gated-aggregation network for medical image segmentation

Recently, transformers have been widely used in medical image segmentation to capture long-range and global dependencies using self-attention. However, they often struggle to learn the local details which limit their ability to capture irregular shapes and sizes of the tissues and indistinct boundaries between the tissues, which are critical for accurate segmentation. To alleviate this issue, we propose a network named GA2Net, which comprises an encoder, a bottleneck, and a decoder. The encoder computes multi-scale features. In the bottleneck, we propose a hierarchical-gated features aggregation (HGFA) which introduces a novel spatial gating mechanism to enrich the multi-scale features. To effectively learn the shapes and sizes of the tissues, we apply deep supervision in the bottleneck. GA2Net proposes to use adaptive aggregation (AA) within the decoder, to adjust the receptive fields for each location in the feature map, by replacing the traditional concatenation/summation operations in skip connections in U-Net like architecture. Furthermore, we propose mask-guided feature attention (MGFA) modules within the decoder which strives to learn the salient features using foreground priors to adequately grasp the intricate structural and contour information of the tissues. We also apply intermediate supervision for each stage of the decoder, which further improves the capability of the model to better locate the boundaries of the tissues. Our extensive experimental results illustrate that our GA2-Net significantly outperforms the existing state-of-the-art methods over eight medical image segmentation datasets i.e., five polyps, a skin lesion, a multiple myeloma cell segmentation, and a cardiac MRI scan datasets. We then perform an extensive ablation study to validate the capabilities of our method. Code is available at https://github.com/mustansarfiaz/ga2net.

TFAN: A Task-adaptive Feature Alignment Network for few-shot website fingerprinting attacks on Tor

Few-shot website fingerprinting (WF) attacks aim to infer which website a user browsed through anonymity networks, such as Tor, using limited labeled traces. Recent methods either adopt complex metric strategies or perform time-consuming transfer learning, neither of which yields the most efficient performance in dynamic network environments. In this paper, we introduce a novel Task-adaptive Feature Alignment Network (TFAN) following the meta-learning paradigm. TFAN regards the few-shot WF attack as a feature alignment problem in class latent space, aiming to depict each location in the query feature map as a weighted sum of support features of a given class. Ridge regression provides a closed-form solution without extra parameters or techniques, ensuring high computational efficiency. Moreover, we also propose a Task-adaptive Modulation Unit (TMU), which activates the differences between support prototypes to generate task-level channel weights, making channels with significant discriminative details for each task contribute more to alignment. Extensive experiments on public Tor datasets demonstrate the superiority of TFAN in different scenarios. Notably, it is the only method that maintains over 90% accuracy in the 1-shot setting even 42 days later. Our code is available at https://github.com/Crybaby98/TFAN.

A spatial map: a propitious choice for constraining the binding problem.

Many studies have shown that the human visual system has two major functionally distinct cortical visual pathways: a ventral pathway, thought to be important for object recognition, and a dorsal pathway, thought to be important for spatial cognition. According to our and others previous studies, artificial neural networks with two segregated pathways can determine objects' identities and locations more accurately and efficiently than one-pathway artificial neural networks. In addition, we showed that these two segregated artificial cortical visual pathways can each process identity and spatial information of visual objects independently and differently. However, when using such networks to process multiple objects' identities and locations, a binding problem arises because the networks may not associate each object's identity with its location correctly. In a previous study, we constrained the binding problem by training the artificial identity pathway to retain relative location information of objects. This design uses a location map to constrain the binding problem. One limitation of that study was that we only considered two attributes of our objects (identity and location) and only one possible map (location) for binding. However, typically the brain needs to process and bind many attributes of an object, and any of these attributes could be used to constrain the binding problem. In our current study, using visual objects with multiple attributes (identity, luminance, orientation, and location) that need to be recognized, we tried to find the best map (among an identity map, a luminance map, an orientation map, or a location map) to constrain the binding problem. We found that in our experimental simulations, when visual attributes are independent of each other, a location map is always a better choice than the other kinds of maps examined for constraining the binding problem. Our findings agree with previous neurophysiological findings that show that the organization or map in many visual cortical areas is primarily retinotopic or spatial.

Recommendation System for Sustainable Day and Night-Time Cultural Tourism Using the Mean Signed Error-Centric Recurrent Neural Network for Riyadh Historical Sites

To accommodate user-specific requirements and preferences, a travel Recommendation System (RS) gives a customized place of interest. The prevalent research did not provide solutions to some essential situations for cultural tourism, including relevant time, environmental conditions, and stay places. Thus, the existing RS models led to unreliable cultural tourism recommendations by neglecting essential factors like personalized itineraries, environmental conditions of the cultural sites, sentiment analysis of the hotel reviews, and sustainable cultural heritage planning. To overcome the above factors, a day- and night-time cultural tourism RS utilizing the Mean Signed Error-centric Recurrent Neural Network (MSE-RNN) is proposed in this paper. The proposed work develops an efficient RS by considering historical data, Geographic Information System (GIS) map location, hotel (stay place) reviews, and environmental data to access day and night cultural tourism. First, from the Geographic Information System (GIS) map and hotel data, the historical and hotel geolocations are extracted. Currently, these locations are fed to Similarity-centric Hamilton Distance-K-Means (SHD-KM) for grouping the nearest locations. Next, hotels are ranked utilizing the Tent Mapping-centric Black Widow Optimization (TM-BWO) approach centered on the locations. In addition, using Bidirectional Encoder Representations from Transformers (BERT), the essential keywords from the historical geo-locations are embedded. In the meantime, the sites’ reviews and timings are extracted from Google. The extracted reviews go through pre-processing, and the keywords from the pre-processed data are extracted. For the extracted keywords, polarity is calculated centered on the Valence-Aware Dictionary for Sentiment Reasoning (VADER). Concurrently, utilizing the Reference-centric Pearson Correlation Coefficient (R-PCC), the timings of the sites are segregated. Lastly, for providing a recommendation of tourist sites, the embedded words, ranked hotels, and segregated timings, along with the pre-processed environment and season data, are fed to the MSE-RNN classifier. At last, the experimental evaluation verified that other recommendation systems were surpassed by the proposed approach.

Actual versus perceived noise levels among critical care nurses and their related adverse effects: A cross-sectional study.

Critical care nurses should help in reducing noise to improve the well-being of patients and health care providers. To measure actual noise levels in intensive care units, identify nurses' perceived irritation levels of noise sources and examine the impact of noise on nurses' work performance and well-being. This cross-sectional study was conducted from January to April 2023 at a teaching hospital's six intensive care units. It involved three phases: mapping locations for noise measurement, actual noise measurements in decibels and a cross-sectional survey to identify nurses' perceptions and the adverse effects of noise. Actual noise was measured between patients' beds, nursing stations and beside 16 noise sources for 7 days 24 h a day. For nurse perceptions, the mean of perceived irritation levels by a Likert scale for each noise source was calculated to present perceived noise levels. Ranking of noise sources according to the actual measured and perceived irritation by nurses was done based on mean values. Curve estimation regression test was used to predict the relationship between actual and perceived noise and stepwise multiple linear regression identified factors associated with noise adverse effects. The mean noise level in the intensive care units was 65.55 dB. Nurses perceived mechanical ventilator alarms as the most irritating noise. However, the mean noise measurements showed that conversations among colleagues were the primary source of noise. There was no significant predictive relationship between the actual and perceived noise. Nurses reported feeling distressed, irritable, fatigued and less productive due to noise. There was a discrepancy between actual and perceived noise levels by nurses. Perceived noise levels had more impact on nurses than actual noise. By incorporating both objective measurements and subjective perceptions into efforts aimed at reducing noise, health care providers can create quieter intensive care units.

TRACKING SYSTEM USING GPS AND SMART CARD AUTHENTIFICATION BASED ON ESP 32 MCU

Logistics distribution is a series of activities that are interconnected in each process. Therefore, an information system is necessary to record, report conditions, and display the current location of items directly. An Android-based application system is vulnerable to spoofing, such as fake GPS. The application is used to falsify the coordinates of digital map locations. This research aims to develop a common tracking system and prevent Fake GPS by employing the System Development Life Cycle method, consisting of several stages, i.e., planning, analysis, design, implementation, testing, and maintenance. In this research, a prototype of the tracker tool and its information system were made. It used an RFID Smart Card for courier identity authentication and a GPS module to track position information on a digital map. RFID and GPS were controlled using the ESP32. Furthermore, the Website served as an information system to read and create a QR Code to identify the goods carried. It received data from the RFID Smart Card and GPS, stored it in the Database, and displayed it online. The test results indicated that the tracker prototype succeeded in sending location data throughout the test and gained an average distance of 6.82 meters, which was different from a commercial GPS device. It had a delay of 268.5 seconds when the location was first read. The tracker prototype had an average power consumption of 1.5 watts, an average battery life of 2 hours, 28 minutes, and 40 seconds, as well as an average battery deficiency of 36.79%. In conclusion, the system test was successful.

Meningioma transcriptomic landscape demonstrates novel subtypes with regional associated biology and patient outcome

Meningiomas, although mostly benign, can be recurrent and fatal. World Health Organization (WHO) grading of the tumor does not always identify high-risk meningioma, and better characterizations of their aggressive biology are needed. To approach this problem, we combined 13 bulk RNA sequencing (RNA-seq) datasets to create a dimension-reduced reference landscape of 1,298 meningiomas. The clinical and genomic metadata effectively correlated with landscape regions, which led to the identification of meningioma subtypes with specific biological signatures. The time to recurrence also correlated with the map location. Further, we developed an algorithm that maps new patients onto this landscape, where the nearest neighbors predict outcome. This study highlights the utility of combining bulk transcriptomic datasets to visualize the complexity of tumor populations. Further, we provide an interactive tool for understanding the disease and predicting patient outcomes. This resource is accessible via the online tool Oncoscape, where the scientific community can explore the meningioma landscape.

Theoretical study of kinetic arrest, shear elastic modulus, and yielding in simple biphasic colloidal mixtures.

Based on integrating microscopic statistical mechanical theories for structure and ideal kinetic arrest at the naive mode coupling level, we study dynamic localization, the linear elastic shear modulus, applied stress induced modulus softening, and the absolute yielding of simple biphasic binary mixtures composed of equal diameter hard and attractive spheres. The kinetic arrest map is a rich function of total packing fraction, strength of attraction, and mixture composition. The gel to attractive ideal glass transition, the degree of glass melting re-entrancy, and the crossover boundary separating repulsive glasses from attractive glasses vary with the mixture composition. Exponential and/or apparent (high) power law dependences of the elastic shear modulus on the total packing fraction are predicted with effective exponents or exponential prefactors that are sensitive to mixture composition and location in the kinetic arrest map. An analysis of the effective mean square force on a tagged particle that induces dynamic localization reveals a compensation effect between structural correlations and degree of particle localization, resulting in the emergence of a weaker dependence of the shear modulus on mixture composition at very high attraction strengths. Based on a microrheologically inspired formulation of how external stress weakens particle localization and the shear modulus, we analyze mechanical-induced modulus softening and absolute yielding, defined as a discontinuous solid-to-fluid stress-induced transition that can occur in either one or two steps. Estimates of the corresponding yield strains predict that the binary mixture becomes more brittle with increasing sticky particle composition and/or attraction strength.

Quantitative Trait Loci Mapping for Adult-Plant Stripe Rust Resistance in Chinese Wheat Cultivar Weimai 8

Wheat stripe rust, triggered by Puccinia striiformis f. sp. tritici, is among the most widespread and damaging wheat (Triticum L.) diseases. The development of cultivars harboring adult plant resistance (APR) to stripe rust is a better approach to control the disease. The current study aimed to map APR to stripe rust via the QTL mapping of 165 F2–6 recombinant inbred lines (RILs), derivatives of Weimai 8/Zhengzhou 5389. The collection of phenotypic data for the stripe-rust resistance of both parents and all 165 RILs were conducted at Baoding, Hebei Province, during the 2016–2017 cropping seasons, and at Mianyang, Sichuan Province, during the 2017–2018 and 2018–2019 sowing seasons. The RIL populations and parents were also genotyped with 860 pairs of simple-sequence-repeat (SSR) primers to map APR QTLs to stripe-rust resistant. Moreover, a 55K SNP chip was used for small group bulk segregant analysis conducted to locate the genetic map location and concentration of the SNP markers on the wheat genome. Inclusive composite interval mapping (IciMapping 3.2) software identified four QTLs of stripe-rust resistance on chromosomes 1B, 2AS, 2BS, and 7DS, named QYr.wmy-1B, QYr.wmy-2AS, QYr.wmy-2BS, and QYr.wmy-7DS, which significantly explained 11.56–16.64%, 9.35–12.70%, 7.27–9.95%, and 11.49–15.07% of the phenotypic variation, respectively. All these QTLs were found from the resistant parent, Weimai 8. Meanwhile, the QTLs located on chromosomes 1B and 2AS were found close to Yr18 and Yr9, respectively. Furthermore, the results indicated that QYr.wmy-1B is possibly Yr9 and QYr.wmy-2AS is similar to Yr18 or might be a new QTL, whilst QYr.wmy-2BS and QYr.wmy-7DS were found to be different from previously reported stripe-rust-resistance QTLs and are possibly new QTLs. Overall, the QTLs and their closely associated molecular markers detected in this study could be a great source of input for marker-assisted selection to adult plant stripe-rust resistance in wheat-breeding programs.

The cerebellum monitors errors and entrains executive networks

Frontal midline θ (Fmθ) activity occurs in medial prefrontal cortices (mPFC), when expected and actual outcomes conflict. Cerebellar forward models could inform the mPFC about this mismatch.To verify this hypothesis we correlated the mPFC activation during a visuomotor tracking task (VM) with performance accuracy, in control and cerebellum-lesioned participants. Additionally, purely visual (V), motor (M) and a motor plus visual tasks (V + M) were performed.An Independent Component, with a mid-frontal topography scalp map and equivalent dipole location in the dorsal anterior cingulate cortex accounted for Fmθ.In control participants Fmθ power increased during VM, when the error level crossed a threshold, but not during V + M, M and V. This increase scaled with tracking error.Fmθ power failed to increase during VM in cerebellar participants, even at highest tracking errors.Thus, in control participants, activation of mPFC is induced when a continuous monitoring effort for online error detection is required. The presence of a threshold error for enhancing Fmθ, suggests the switch from an automatic to an executive tracking control, which recruits the mPFC.Given that the cerebellum stores forward models, the absence of Fmθ increases during tracking errors in cerebellar participants indicates that cerebellum is necessary for supplying the mPFC with prediction error-related information. This occurs when automatic control falters, and a deliberate correction mechanism needs to be triggered.Further studies are needed to verify if this alerting function also occurs in the context of the other cognitive and non-cognitive functions in which the cerebellum is involved.

Abstract 17749: Regionalization of Non-Pulmonary Vein Triggers for Atrial Fibrillation When the P Wave is Obscured Using Non-Invasive Electrocardiographic Imaging QRS-T Subtraction Algorithm

Introduction: Ablation of non-pulmonary vein triggers (NPVTs) after pulmonary vein isolation (PVI) may reduce atrial fibrillation (AF) recurrence. Localizing a trigger which initiates AF after a single atrial ectopic beat is challenging, especially in the scenario when the trigger P wave is obscured by preceding QRS-T complex. Aim: To evaluate the potential for noninvasive electrocardiographic imaging (ECGi) to localize NPVTs when the P wave morphology is superimposed on the T wave of the previous beat. Methods: We developed an algorithm which overlays and subtracts the preceding QRS-T wave complex from the QRS-T wave complex which is obscuring the P wave of interest, thus revealing the P wave morphology (Figure 1A). Resultant unobscured P waves (from multiple body surface electrodes) are then used for ECGi computation. In five patients undergoing AF ablation, after PVI, we paced from 15 atrial sites where NPVTs commonly arise, and evaluated the epicardial activation maps generated by ECGi both when pacing was timed to ensure an unobscured P wave and when timed to coincide with preceding QRS-T complex. Co-registration of CT-based ECGi activation maps with invasive electroanatomic map (EAM) allowed comparison of the earliest activation site on ECGi map from both the obscured P waves after QRS-T subtraction and unobscured P waves with true pacing locations on EAM (Figure 1B). Results: From 146 pacing sites in our patient cohort, for the unobscured P waves, median distance between earliest site on ECGi map and EAM pacing location was 16 mm (10-21 mm), and for obscured P waves after QRS-T subtraction, median distance was also 16 mm (12-23 mm) (Figure 1C). Conclusion: Using a QRS-T subtraction algorithm, ECGi can approximate origin of paced P waves whether P wave is unobscured or obscured by the preceding QRS-T complex. Spontaneous NPVT P waves are commonly obscured by the QRS-T wave and the ability to rapidly localize an early coupled P wave may facilitate NPVT mapping and ablation.

Analysis of garbage collection network of Colombo district using centrality measures

Waste management is a common problem faced by all developing countries. Colombo city faces the biggest garbage problem than other cities in Sri Lanka. Even through many studies were carried out for waste management problem using different approaches, there were very few research findings were available using graph theoretical approach. In this research, applications of graph theory in garbage collection procedure are depicted. The study mainly focuses on analyzing the garbage collection procedure of Colombo municipal council area in western province through constructing garbage collection network and using centrality measures. Centrality measures are used to compute the importance of any node in a network. Colombo municipal area divides into 6 main administrative districts, and each of these is divided into municipal wards with several junctions and streets. Garbage collection network was initially constructed by assigning a node by a location in google map, and an edge by a street or a path between two locations. Constructed network is an undirected unweighted graph and betweenness, closeness, degree, and eigenvector centrality measures are used to find central locations of the network. By identifying central locations, some machines or recycling trucks can be placed in that central places to deposit the waste. Next, a weighted graph was constructed by taking the weights of an edge as a fraction of weight of collected garbage between two locations. Collected garbage weights and betweenness and degree centrality values for weighted graph are used to identify the shortest paths between central nodes in each municipal ward. Garbage collection trucks can be followed this shortest path in order to reduce their fuel cost and collection time.

An Examination of Digital Geography Games and Their Effects on Mathematical Data Processing and Social Studies Education Skills

"This study aims to advance the development of the mathematical processing skills of students by suggesting the use of digital geography games. This includes an analysis of its contribution to the standard mathematics curriculum in areas such as data processing as well as its contribution to social studies curricula in areas such as map literacy, location analysis, problem solving, and other skills related to understanding tables, graphs, and diagrams. The study also examines the findings of the experts that relate to these dynamics. A case study of a digital geography game called Gezgin, developed by İneç (2021) is examined in this research using qualitative research approaches. Under this framework, the data obtained by critical case sampling from six experts through a semi-structured online interview were collected with cloud technologies and examined by using a content analysis. The findings obtained showed that the use of Gezgin can help develop skills related to data processing, problem solving, problem formulation, general mathematical processes, the ability to transfer mathematics to real life, and the ability to create and correctly interpret tables and graphs. The findings also indicate that the real-life context that is provided by this game supports educational development in the areas of map literacy, location analysis, problem-solving skills and graph, table and diagram creation and interpretation for social studies curricula. The expert opinions about Gezgin were determined to be mostly positive, especially with respect to the interdisciplinary structure and its rich content, but some of its functions were found to be limited."

ASSESSMENT OF CORROSION IN A PARKING DECK USING GPR

This research focused on finding the structural condition of a precast parking deck using a GPR. A GSSI SIR 4000 Bridge Scanner GPR was deployed for corrosiveness mapping of a precast deck. Small concrete slabs were prepared in the laboratory with fresh and corroded rebars to identify their differences in GPR scanned images. The GPR response from the slab indicated that the reflection amplitude obtained from the scan of the target rebar decreases with increasing depth. GPR B-scans from the fresh and corroded rebar indicated increase in corrosion. The field experiment was performed following the standard bridge deck survey procedures. Both numerical and image-based analysis methods were followed for developing the corrosiveness maps of the precast deck section. The corrosiveness map showed a few critical sections in the precast deck. A visual inspection of the precast deck matched the fault locations in the corrosiveness map. The present condition of a precast deck section was found satisfactory except for a few areas of serious cracking that need repairs to control the further growth of corrosion. GPR results showed higher accuracy with the field inspection outcomes demonstrating that a GPR can be used as a reliable non-destructive tool for the condition assessment of concrete structures.

A Head-Mounted Assistive Device for Visually Impaired People with Warning System from Object Detection and Depth Estimation

People with visual impairment use white cane as their traditional method for perceiving the surroundings. However, the utilization of a cane is limited by its length and orientation. In Thailand, the obstacles on paveway in daily life are not located only on the floor but also above knee level which sometimes could be harmful to pedestrians, especially blind people. A head-mounted assistive device is developed to be an enhancement used with a cane for the visually impaired to comprehend their environment both lower and higher the knee level. The assistive device is designed to be compact and light-weight. It could also send the tactile feedback as a warning from vibration motors mounted on the device. To generate a warning signal, YOLOv4 is used to detect the location of obstacles and depth map from the stereo camera is used to estimate the distance mapping into 4 defined ranges: dangerous, very close, close and fine. The results indicate that the head-mounted assistive device has the ability to perceive obstacles locating farther than 0.9 m. The prediction returned 9.23%, 14.63% and 7.86% error when estimating the depth of obstacles at 1.3 m., 2.8 m. and 4.2 m. respectively. The average execution time for the device to return the command controlling vibration motors is 0.13 second and the maximum estimated time for the motor to send the haptic feedback is 1.05 second.

The empirical study of Joomla CMS map extension and location performance

Thousands of extensions can be installed on the Joomla CMS with various functions. One of them is the map and location extension, which is useful for meeting the needs of content that display information in the form of visual maps and locations. The Phoca Maps and MX Maps extensions are two of the many map and location extensions available on the Joomla Extension Directory website, downloadable and widely used. This study aims to provide a reference for Joomla CMS users in terms of managing content related to maps and locations through empirical studies of the performance of Phoca Maps and MX Maps extensions. In measuring extension performance, Google Lighthouse is used to audit all quality aspects that support the performance of a web application. The research results found that, in general, the desktop and mobile performance of the Phoca Maps and MX Maps extensions was unsatisfactory. This can be seen from the performance testing results for First Contentful Paint, Speed Index, Largest Contentful Paint, Time to Interactive, Total Blocking Time, and Cumulative Layout Shift.

Automating the external placement of symbols for point features in situation maps for emergency response

ABSTRACT In this article, we address the time-critical work of emergency services in the field of disaster and emergency response. Aiming at saving valuable human and time resources during emergency operations, we present one exact and one heuristic approach for the automatic placement of tactical symbols in situation maps. Such maps are used to establish situational awareness and to convey mission-relevant information to emergency personnel. Usually, the information is communicated through the visualization of descriptive symbols which are predominantly placed in a manual process. We automate this process based on an established map layout used by emergency services in Germany that distributes the symbols to the map boundaries. Following general principles and observations from existing literature, we formalize the symbol placement as an optimization problem. We take into account the relevance of tactical symbols as well as short and crossing-free leaders and allow the grouped representation of symbols of similar semantics and spatially close map locations. In experiments with real-world data, we determine a balance between the optimization criteria and show that our heuristic generates high-quality results in less than a second. In an assessment by an expert, we get confirmation that our maps are suitable for use in emergency scenarios.

PO-05-111 IMPLANTING A NOVEL ACTIVE-FIXATION LEADLESS PACEMAKER: A SINGLE CENTER EXPERIENCE WITH THE AVEIR VR

The new Aveir VR (Abbott Medical, CA) active-fixation leadless pacemaker (LP) offers several novel innovations. It uses a unique mapping capability to help reduce repositioning attempts prior to fixation and utilizes a helical fixation mechanism for implantation and chronic retrieval. We describe the current largest real world descriptive single center experience with the new Aveir VR LP. This retrospective study describes the characteristics and outcomes of patients who underwent implantation with the single chamber Aveir LP between May 2022 and December 2022. Data was collected from patients’ electronic medical records, dictation forms and procedural logs. Variables collected included demographics (eg age, sex, race), procedural characteristics (eg procedure length, fluoroscopic duration), hospital length of stay and time to discharge, pacing parameters and complications. A total of 48 patients underwent implantation with the single chamber Aveir LP. The most common indications were symptomatic bradycardia due to sinus node dysfunction (55%) and atrial fibrillation with bradycardia (29%). The average age of patients was 72.5 years, 51% were male, and 53% were African Americans. The average procedure duration was 34.3 minutes (range 15–106) and average fluoroscopy time was 13.4 minutes (range 1.4–41.6). Procedure duration improved from a median of 36.0 minutes in the first 10 cases to a median time of 26.0 minutes in the last 10 cases done by the same operator. The average number of mapping locations was 1.6 prior to fixation, implant location was low septal in 84% of patients, and 8.3% of patients required repositioning. The average R wave amplitude at implant was 8.3 mV (range 3.0–18), average impedance was 789 Ω (range 380–1800), and average pacing threshold was 0.87V (range 0.25–2.5) at 0.4ms. There were no periprocedural complications with any of the implantations. The average hospital length of stay was 13 days (range 0.5–63), however the average time from implant to discharge in patients presenting electively was 15 hours. Our experience demonstrates that implantation of the single chamber Aveir VR LP has been safe and effective and is comparable to trial data.

A new vibro-impact bistable oscillator with an adjustable rigid wall

In this paper, a new vibro-impact bistable oscillator under vicious damping and external harmonic excitation is proposed by adding an adjustable rigid wall to one side of the archetypal smooth and discontinuous (SD) oscillator and an impact mapping is given to describe energy loss during collisions. In the unperturbed ideal case, there exist rich and perfect geometrical structure including grazing phenomena such as periodic orbits and homoclinic orbits tangent to the wall due to its adjustability as a constraint. Perturbed dynamics is studied to show the influence of the constraint on the original SD oscillator through the Lyapunov exponent diagrams, bifurcation diagrams, and the corresponding phase diagrams and attractors. Some new non-smooth chaotic attractors and periodic orbits are found to have grazing or transversal interaction with the unilateral rigid wall. Due to the effect of the introduced impact mapping and different locations of the rigid wall, the finger-like chaotic attractors of the SD oscillator will be suppressed and changed into different non-smooth periodic motions by varying the non-dimensional parameter which reflects the degree of the springs compressed, while the periodic motions of the SD oscillator will become new non-smooth chaotic attractors or different non-smooth periodic motions.