Similar Objects Research Articles

Knowledge Leaks in Data-Driven Business Models? Exploring Different Types of Knowledge Risks and Protection Measures

AbstractData-driven business models imply the inter-organisational exchange of data or similar value objects. Data science methods enable organisations to discover patterns and eventually knowledge from data. Further, by training machine learning models, knowledge is materialised in those models. Thus, organisations might risk the exposure of competitive knowledge by sharing data-related value objects, such as data, models or predictions. Although knowledge risks have been studied in traditional business models, little research has been conducted in the direction of data-driven business models. In this explorative qualitative study, we conducted 28 expert interviews in three rounds (two exploratory and one evaluatory) and identified five types of risks along the three basic types of value objects: data, models and predictions. These risks depend on the context, i.e., when competitive knowledge could be discovered from shared value objects. We found that those risks can be mitigated by technology, contractual regulations, trusted relationships, and adjusting the business model design. In this study, we show that the risk of knowledge leakage is a relevant risk factor in data-driven business models. Overall, knowledge risks should be considered already during business model design, and their management requires an interdisciplinary approach via a balanced assessment. The level of knowledge protection from a technology perspective highly depends on computer science innovations and thus is a moving target. As an outlook, we suggest that knowledge risk will become even more relevant with the extensive usage of machine learning and artificial intelligence in data-driven business models.

Strategic Planning & Industry Sector Enhancing SDGS

Objective: The objective of this study is to explore the nature of strategic planning (SP) in four selected industry sectors (IS) in regard to the SP-IS relationships, the features and aspects that influence SP in and within one industry as well as with the selected industry sectors. Design/methodology/approach: A total of 28 related studies were selected from electronic academic resources and databases (e.g., Google scholar, Emerald, and Academia …etc.). The criteria used in selection is based on the easiest and most accessible documents to the researcher by using the title of the study with similar terms and words for the selected industry sectors. Four sectors have been selected: SP in banking, tourism & hospitality, healthcare, and higher education sector. The selected study samples were conducted in different countries of the world. Tables used are divided into columns for summarizing the essential data for each study such as study title, type of industry sector and country, findings, SP components, and its influence on performance. Selected studies have been carefully reviewed and evaluated. The methodology and construct of each study is considered, and the content analysis is used in addition to the researcher’s real-life experiences, as well as the opinions of academic peers were considered. Findings: The purpose of every examined study for each industry sector was identified and compared with same industry and with other examined industry sectors. The majority of the studies reviewed had similar objectives. The SP and SM concepts are well-known, understood, and used in many industry sectors. The findings show that SP has a favorable influence, and repeated elements and dimensions have been identified. More importantly, all of the evaluated studies have titles that include SP, strategic implementation (SI), or strategic management (SM) either explicitly or implicitly. Research limitations/implications: The results of the study are related to chosen studies of 4 industry sectors. As such, it is not possible to generalize these findings. The restricted accessibility to the relevant databases, journals, and web resources is another research barrier. Moreover, this kind of study—or one comparable to it—requires a longitudinal research approach. As such, the writer makes every attempt to condense the information that is accessible and comprehensible to him. Originality/value: This study highlights the SP-IS relationship of four important industry sectors in different countries with varied SP comparative features.

SPORTS IN AUSTRALIA’S SOFT POWER STRATEGY: OPPORTUNITIES FOR IMPLEMENTATION BY OTHER COUNTRIES

Australia, being a successful example of using sports for foreign policy, has significantly improved its international influence in the Pacific region. Yet, political, cultural, and economic peculiarities can doubt the similar application of sports by other countries. This article examines Australia’s use of sports and sports diplomacy as key instruments of its international strategy. The purpose of the article is to analyze Australia’s use of sports within soft power efforts, explore its methods, principles, and frameworks, and evaluate whether this framework can be applied by other countries to achieve similar soft power objectives. This study performs a comprehensive review of literature, official Australian government publications, and specific case studies to understand the outcomes and applicability of the approach. The novelty of the research lies in its detailed examination of the specific conditions and strategies that have made Australia’s sports diplomacy successful. Key research findings highlight that Australia’s effective use of sports diplomacy is rooted in its effect of sports on national identity, strong sports culture, advanced infrastructure, strategic partnerships, and connections with communities, particularly within the Pacific region. The article proves that the 2015-18 and 2030 Sports Diplomacy Strategies have successfully fostered cultural, sports, and people-to-people connections and enhanced Australia’s influence and presence globally. The article concludes that while Australia’s sports diplomacy model is highly effective, its application by other countries may be challenging. The reasons refer to varying levels of national perception of sports, sports culture, financial resources, and international influence. For actors with similar conditions, a comprehensive approach is applicable, whereas for emerging and developing nations it may be best to adopt specific elements of the strategies depending on the needs and resources.

GuidingBand: Evaluating Speed, Precision and Accuracy of a Vibrotactile Hand Guidance System

Abstract Computerized tactile guidance systems can potentially help in human visual perception tasks such as identifying a desired object in a collection of similar objects. We designed a wrist-wearable tactile guidance system called GuidingBand that provides vibrational cues to help the user pick visual targets out of an array. We conducted three studies to systematically investigate the interplay of machine-led tactile guidance and human visual perception. The studies involve presenting visual targets to users on a screen and giving them visual search tasks. In Study 1, we identified the error rate of our guidance system. We presented participants (N=20) with arrays of identical, square targets to pick from, progressively reduced the target sizes and evaluated error rates for each size. Notably, we observed a 4% error rate at a target size of 10 mm. In Study 2, we compared the error rate of the guidance system with and without the help of human visual perception in a visual search task. We constructed a task that involved showing users an array of distractor rectangles (set sizes 2 to 10) varying only in length and asked them to identify the correct target that was previously shown to them. Participants (N=13) had fewer errors when they tried to identify targets with tactile guidance alone, followed by guidance and perception combined and perception alone. In Study 3, we had the same task as Study 2 but the distractor set sizes were larger (varying from 4 to 28), we had more participants (N=30) and measured errors and task time. While perception alone was the fastest, it was also the most error prone. The combined mode was faster and less error prone than guidance only mode, as expected, indicating that human–computer collaboration yielded the best performance.

Experimental Vapor Pressure Determination for C2H4, C2H6, CH3OH, CH4, CO, CO2, H2O, and N2 Molecules for Astrophysical Relevant Temperatures. Implications for the Presence of Volatiles in Kuiper Belt Objects and Trans-Neptunian Objects

Vapor pressure is a relevant quantity that is necessary in order to improve the study of the atmosphere dynamics that take place within astrophysical scenarios. The aim of this study was to obtain the vapor pressure values of the following molecules: C2H4, C2H6, CH3OH, CH4, CO, CO2, H2O, and N2 through experimentation, as well as to determine their empirical relationship with the temperature, applying the results to the persistence of volatiles in trans-Neptunian objects (TNOs) and Kuiper Belt objects (KBOs). The experimental determination was performed by measuring the sublimation rate for each molecule at different temperatures. The Hertz–Knudsen equation was used to obtain the vapor pressures for the aforementioned molecules, taking the necessary considerations into account, and the sublimation rate was measured using a quartz crystal microbalance. In order to check the validity of the methods used, the results obtained for water ice were compared with those of previous studies from the literature. The values obtained for CO, N2, and CH4 are of particular interest in the study of the TNOs' and KBOs' atmosphere composition. The results of this study improve the understanding of the surface and atmospheric composition of objects in the cold scenarios of the solar system, in particular, in KBOs and TNOs.

Exploring cost changes with time-driven activity-based costing after service delivery redesign in Dutch maternity care.

The implementation of Value-Based Healthcare (VBHC) has spread across international healthcare systems, aiming to improve decision-making by combining information about patient outcomes and costs of care. Time-Driven Activity-Based Costing (TDABC) is introduced as a pragmatic yet accurate method to calculate costs of care pathways. It is often applied to demonstrate value-improving opportunities, such as interventions aimed at service delivery redesign. It is imperative for healthcare managers to know whether these interventions yield the expected outcome of improving patient value, for which TDABC is also suitable. However, its application becomes more complex and labour intensive if the intervention extends beyond activity-level changes in existing care pathways, to the implementation of entirely new care pathways. The complexity arises from the potential influence of such interventions on the costs of related care pathways. To fully comprehend the impact of such interventions on organizational costs, it is important to include these factors in the cost calculation. Given the substantial effort required for this analysis, this may explain the limited number of prior TDABC studies with similar objectives. This methodological development paper addresses this gap by offering a pragmatic enrichment of the TDABC methodology. This enrichment is twofold. First, it provides guidance on calculating a change in costs without the need for a total cost calculation. Second, to secure granularity, a more detailed level of cost-allocation is proposed. The aim is to encourage further application of TDABC to conduct financial evaluations of promising interventions in the domain of VBHC and service delivery redesign.

Natural ventilation cooling effectiveness classification for building design addressing climate characteristics

The evaluation of natural ventilation potential for effective sustainable options and innovative green building design strategies is of great interest to architects, researchers and governments. From a retrospective review, we found that the potential evaluation of natural ventilation (NV) cooling effectiveness in the same category based on similar meteorological uncertainty, research objectives and objects showed significant differences. Uncertainties added and uncertainty propagation (both model form uncertainties and parameter uncertainties) could result in large discrepancies between simulation outcomes and real scenarios, especially in the design performance modeling (DPM) phase. In this conceptual design stage, a few parameters are available and therefore decisive. It is necessary to review and identify the key performance indicators and explore the extent to which deviations are caused by inconsistencies or biases in model information. As a basis for more concrete research, we propose statistical tests based on quantitative evaluations to explore the rule of natural ventilation potential volatility and identify whether there is a significant potential improvement resulting from the critical parameter enhancement with the optimal relationship. The showcase is applied in China, where there has been a significant amount of criticism regarding the current building climate zoning due to the perceived coarseness of the system and where there has been an active exploration into the possibility of redefining building climate zoning with a view toward improving its accuracy and effectiveness.

Community-University Partnerships: The Benefits of Collaboration in Measuring Public Support for a Community Recreation Center

Community recreation centers (CRCs) are gaining popularity across the country. While many support the argument that CRCs improve quality of life by building social capital and improving the physical health of residents, that support does not necessarily translate into community support for the funding and construction of CRCs. Some communities undertake surveys to try to gauge the support for CRCs but have had mixed results on the insights provided by those surveys. Furthermore, public perceptions about the accuracy and usefulness of survey data could lead to stakeholder disregard for the data produced by them. This case study focuses on the benefits of a robust partnership between a local community and a regional university in developing a survey research project to analyze support for building a CRC. In this paper, we emphasize the value of producing trusted data and provide lessons on how community-university partnerships can achieve similar objectives. The first lesson is that community-university partnerships, by emphasizing local connections, can help foster trust in survey research projects. Second, strategic community-university partnerships can derive additional benefits such as division of labor, expertise, and cost savings. Third, by embracing the above two benefits, collaboration is not only possible, but can produce tailored survey research projects that provide stakeholders insights into critical questions. Finally, community-university partnerships that are structured around shared values can help communities solve critical policy issues effectively and efficiently. This case study details these lessons through an examination of a robust community-university partnership that led to the passage of a ballot referendum to build a CRC. This community-university model of collaboration provides a framework for communities and universities to work together to serve the public good.

MODERNIZATION OF REAL ESTATE VALUАTION METHODOLOGY BY COMPARATIVE METHOD

This study is devoted to the issue of determining the price of a real estate object based on the use of statistical market evaluations of similar objects. In the course of the research, a technique for determining the price of a real estate object was developed using parametric equations of the least squares method, which allows using an unlimited amount of input information and obtaining equalized values of price-forming factors. In contrast to the existing methods of the comparative approach to determining the price of the object of assessment, the proposed method allows you to obtain the value of the price-forming factors, and then the price of the object without establishing the difference between the factors influencing the price, as is the case with the classical approach of processing the input database. Approbation of the developed methodology showed the effectiveness of the possibility of its application in practice.

MODERNIZATION OF REAL ESTATE VALUАTION METHODOLOGY BY COMPARATIVE METHOD

This study is devoted to the issue of determining the price of a real estate object based on the use of statistical market evaluations of similar objects. In the course of the research, a technique for determining the price of a real estate object was developed using parametric equations of the least squares method, which allows using an unlimited amount of input information and obtaining equalized values of price-forming factors. In contrast to the existing methods of the comparative approach to determining the price of the object of assessment, the proposed method allows you to obtain the value of the price-forming factors, and then the price of the object without establishing the difference between the factors influencing the price, as is the case with the classical approach of processing the input database. Approbation of the developed methodology showed the effectiveness of the possibility of its application in practice.

Priority directions in the design of a youth culture and leisure center in Khuzhir settlement

We consider the relevance and importance of creating a youth culture and leisure center in the rural locality of Khuzhir. To this end, the results of sociological surveys among the population of the Olkhonsky District and young people of the Russian Federation, who form the main target audience of the youth center, were used. The research also involved a review of electronic sources and publications on the design of culture and leisure centers in the settlements of the Baikal coastal area, statistical data on tourism activities in the area of Olkhon Island and additional education initiatives in Russia, sociological surveys among Olkhon population and residents of the Russian Federation and CIS countries. A review of project proposals for the organization of leisure, culture, and education institutions in rural areas of Pribaikalye was carried out. All these findings were used to identify the main requirements to a youth center in Khuzhir. The analysis of priority areas in the field of additional education specified at the end of 2022 in Russia and the Siberian Federal District was used to determine a set of functions to be performed by the center. The results also formed the basis for the selection of similar objects of domestic and foreign experience for analysis and determination of the most optimal architectural and planning solutions of the designed center. The key stages in the organization of a youth culture and leisure center in Khuzhir were determined taking the needs of the target audience into account.

Priority directions in the design of a youth culture and leisure center in Khuzhir settlement

We consider the relevance and importance of creating a youth culture and leisure center in the rural locality of Khuzhir. To this end, the results of sociological surveys among the population of the Olkhonsky District and young people of the Russian Federation, who form the main target audience of the youth center, were used. The research also involved a review of electronic sources and publications on the design of culture and leisure centers in the settlements of the Baikal coastal area, statistical data on tourism activities in the area of Olkhon Island and additional education initiatives in Russia, sociological surveys among Olkhon population and residents of the Russian Federation and CIS countries. A review of project proposals for the organization of leisure, culture, and education institutions in rural areas of Pribaikalye was carried out. All these findings were used to identify the main requirements to a youth center in Khuzhir. The analysis of priority areas in the field of additional education specified at the end of 2022 in Russia and the Siberian Federal District was used to determine a set of functions to be performed by the center. The results also formed the basis for the selection of similar objects of domestic and foreign experience for analysis and determination of the most optimal architectural and planning solutions of the designed center. The key stages in the organization of a youth culture and leisure center in Khuzhir were determined taking the needs of the target audience into account.

The story of SN 2021aatd: A peculiar 1987A-like supernova with an early-phase luminosity excess

There is a growing number of peculiar events that cannot be assigned to any of the main classes. SN 1987A and a handful of similar objects, thought to be explosive outcomes of blue supergiant stars, is one of them: while their spectra closely resemble those of H-rich (IIP) SNe, their light curve (LC) evolution is very different. Here we present the detailed photometric and spectroscopic analysis of SN 2021aatd, a peculiar Type II explosion. While its early-time evolution resembles that of the slowly evolving double-peaked SN 2020faa (although at a lower luminosity scale), after sim 40 days its LC shape becomes similar to that of SN 1987A-like explosions. In addition to comparing LCs, color curves, and spectra of SN 2021aatd to those of SNe 2020faa, 1987A, and other objects, we compared the observed spectra with our own SYN++ models and with the outputs of published radiative transfer models. We also carried out a detailed modeling of the pseudo-bolometric LCs of SNe 2021aatd and 1987A with a self-developed semi-analytical code, assuming a two-component ejecta (core + shell), and involving the rotational energy of a newborn magnetar in addition to radioactive decay. We find that the photometric and the spectroscopic evolution of SN 2021aatd can be well described with the explosion of a sim 15 $M_ blue supergiant star. Nevertheless, SN 2021aatd shows higher temperatures and weaker Na i D and Ba ii lines than SN 1987A, which is instead reminiscent of IIP-like atmospheres. With the applied two-component ejecta model (accounting for decay and magnetar energy), we can successfully describe the bolometric LC of SN 2021aatd, including the first sim 40-day phase showing an excess compared to 87A-like SNe, but being strikingly similar to that of the long-lived SN 2020faa. Nevertheless, finding a unified model that also explains the LCs of more luminous events (e.g., SN 2020faa) is still a matter of debate.

Bridge the gap between practical application scenarios and cartoon character detection: A benchmark dataset and deep learning model

The success of deep learning in the field of computer vision makes cartoon character detection (CCD) based on target detection expected to become an effective means of protecting intellectual property rights. However, due to the lack of suitable cartoon character datasets, CCD is still a less explored field, and there are still many problems that need to be solved to meet the needs of practical applications such as merchandise, advertising, and patent review. In this paper, we propose a new challenging CCD benchmark dataset, called CCDaS, which consists of 140,339 images of 524 famous cartoon characters from 227 cartoon works, game works, and merchandise innovations. As far as we know, CCDaS is currently the largest dataset of CCD in practical application scenarios. To further study CCD, we also provide a CCD algorithm that can achieve accurate detection of multi-scale objects and facially similar objects in practical application scenarios, called multi-path YOLO (MP-YOLO). Experimental results show that our MP-YOLO achieves better detection results on the CCDaS dataset. Comparative and ablation studies further validate the effectiveness of our CCD dataset and algorithm.

The Discovery and Evolution of a Possible New Epoch of Cometary Activity by the Centaur (2060) Chiron

Centaurs are small solar system objects on chaotic orbits in the giant planet region, forming an evolutionary continuum with the Kuiper Belt objects and Jupiter-family comets. Some Centaurs are known to exhibit cometary activity, though unlike comets, this activity tends not to correlate with heliocentric distance, and the mechanism behind it is currently poorly understood. We utilize serendipitous observations from the Asteroid Terrestrial-impact Last Alert System, Zwicky Transient Facility, Panoramic Survey Telescope and Rapid Response System, Dark Energy Survey, and Gaia in addition to targeted follow-up observations from the Las Cumbres Observatory, TRAnsiting Planets and PlanetesImals Small Telescope South (TRAPPIST-South), and Gemini North telescope to analyze an unexpected brightening exhibited by the known active Centaur (2060) Chiron in 2021. This is highly indicative of a cometary outburst. As of 2023 February, Chiron had still not returned to its prebrightening magnitude. We find Chiron's rotational lightcurve, phase curve effects, and possible high-albedo surface features to be unlikely causes of this observed brightening. We consider the most likely cause to be an epoch of either new or increased cometary activity, though we cannot rule out a possible contribution from Chiron's reported ring system, such as a collision of as-yet-unseen satellites shepherding the rings. We find no evidence for a coma in our Gemini or TRAPPIST-South observations, though this does not preclude the possibility that Chiron is exhibiting a coma that is too faint for observation or constrained to the immediate vicinity of the nucleus.

A lightweight target tracking algorithm based on online correction for meta-learning

The traditional Siamese network based object tracking algorithms suffer from high computational complexity, making them difficult to run on embedded devices. Moreover, when faced with long-term tracking tasks, their success rates significantly decline. To address these issues, we propose a lightweight long-term object tracking algorithm called Meta-Master-based Ghost Fast Tracking (MGTtracker),which based on meta-learning. This algorithm integrates the Ghost mechanism to create a lightweight backbone network called G-ResNet, which accurately extracts target features while operating quickly. We design a tiny adaptive weighted fusion feature pyramid network (TiFPN) to enhance feature information fusion and mitigate interference from similar objects. We introduce a lightweight region regression network, the Ghost Decouple Net (GDNet) for target position prediction. Finally, we propose a meta-learning-based online template correction mechanism called Meta-Master to overcome error accumulation in long-term tracking tasks and the difficulty of reacquiring targets after loss. We evaluate the algorithm on public datasets OTB100, VOT2020, VOT2018LT, and LaSOT and deploy it for performance testing on Jetson Xavier NX. Experimental results demonstrate the effectiveness and superiority of the algorithm. Compared to existing classic object tracking algorithms, our approach achieves a faster running speed of 25 FPS on NX, and real-time correction enhances the algorithm’s robustness. Although similar in accuracy and EAO metrics, our algorithm outperforms similar algorithms in speed and effectively addresses the issues of significant cumulative errors and easy target loss during tracking. Code is released at https://github.com/ygh96521/MGTtracker.git.

From the Concept of Storing Documents in Electronic Form to the Regulatory and Legal Basis of Creating National Archival and Library Information Resources

The aim of the article is to study conceptual principles of storing documents in electronic form, in particular, electronic documents, digital documents and creating metadata for them, taking into account integration processes of grounding national information resources in archival and library spheres of activity. Additionally, to trace tendencies in the implementation of existing concepts, to identify the best Ukrainian practices, to highlight defects, and offer possible ways to solve problems. Research methods. This study uses the following methods: theoretical, as moving from the abstract to the concrete, reality reflection in thinking; empirical, as observation and comparison; complex, as system analysis, synthesis and modulation; special, as graphic and component analysis; prognostication. Scientific novelty consists in implementating a systematic interdisciplinary comparative analysis of the problem of storing documents in electronic form in archives and libraries, in order to determine the directions for solving this problem, using the definition of common requirements for similar information objects and processes, particularly, in the context of the initiative to create the National Electronic Library of Ukraine, in which it is offered to integrate information on objects of national heritage stored in archives, libraries, museums, as well as thereafter data from publishers. Main conclusions. Based on the results of this research, it should be stated that Ukrainian archivists achieved the greatest success in developing the overall system from creation the documents in electronic form to their transmission for permanent storage. An important issue is the development of the “long-term storage” system, the formation of which, in our opinion, should begin with the requirements for the information objects with which this system will be filled. This will significantly affect the structure and content of the metadata needed to manage this system. The successful experience of Ukrainian archivists and librarians should be used here. The most urgent task is to put the finishing touches to the Concept of creating the National Electronic Library of Ukraine according to the best domestic and foreign practices.

Properties of outer solar system pebbles during planetesimal formation from meteor observations

Observations of proto-planetary disks, as well as theoretical modeling, suggest that in the late stages of accretion leading up to the formation of planetesimals, particles grew to pebbles the size of 1-mm to tens of cm, depending on the location and ambient conditions in the disk. That is the same size range that dominates the present-day comet and primitive asteroid mass loss. Meteoroids that size cause visible meteors on Earth. Here, we hypothesize that the size distribution and the physical and chemical properties of young meteoroid streams still contain information about the conditions in the solar nebula during these late stages of accretion towards planetesimal formation. If so, they constrain where long-period (Oort Cloud) comets, Jupiter-family (Scattered Disk Kuiper Belt) comets, and primitive asteroids (Asteroid Belt) formed. From video and visual observations of 47 young meteor showers, we find that freshly ejected meteoroids from long-period comets tend to have low bulk density and are distributed with equal surface area per log-mass interval (magnitude distribution index χ ~ 1.85), suggesting gentle accretion conditions. Jupiter-family comets, on the other hand, mostly produce meteoroids twice as dense and distributed with a steeper χ ~ 2.15 or even χ ~ 2.5, which implies that those pebbles grew from particles fragmenting in a collisional cascade or by catastrophic collisions, respectively. Some primitive asteroids show χ > 2.5, with most mass in small particles, indicating an even more aggressive fragmentation by processes other than mutual collisions. Both comet populations contain an admixture of compact materials that are sometimes sodium-poor, but Jupiter-family comets show a higher percentage (~8% on average) than long-period comet showers (~4%) and a wider range of percentages among comets. While there are exceptions in both groups, the implication is that most long-period comets formed under gentle particle growth conditions, possibly near the 30 AU edge of the Trans Neptunian Disk, while most Jupiter family comets formed closer to the Sun where pebbles reached or passed the fragmentation barrier, and primitive asteroids formed in the region where the cores of the giant planets formed. This is possible if the Scattered Disk represents all objects scattered by Neptune during its migration, while the present-day outer Oort cloud formed only during and after the time of the planet instability, well after the Sun had moved away from sibling stars.

The many ages of Triton: New crater counts on the voyager high-resolution image sequence and implications for impactor provenance

Triton is sparsely cratered overall, but because of the high concentration of its impact craters on the leading hemisphere of motion, a dominantly prograde planetocentric origin for the impactors has been hypothesized. With only a modest heliocentric contribution, the average age of Triton's datable terrains could be no more than ~10 Ma, which would make Triton the most globally active icy satellite of all. This is obviously important, but is it true? There are clear stratigraphic age differences between terrains on Triton's leading hemisphere, especially on the 10-frame high-resolution Voyager 2 mosaic, which complicates simple or facile interpretations of the crater spatial distribution. Moreover, crater counts on the high-resolution mosaic, which we present here, indicate a steep slope for the impactor size-frequency distribution (SFD) at small (sub-km) sizes, completely at odds with crater counts on Charon, nominally the best estimate of the time-integrated Kuiper belt flux (Charon's corresponding SFD slope being quite shallow in comparison). Most likely, this implies that the smaller craters we measure on Triton are indeed predominantly planetocentric, but the origin of such a geologically recent prograde impactor swarm is puzzling. Here we consider several possible sources or explanations in detail, and find debris from a collision or collisions between neptunian irregular satellites, to be the least objectionable, albeit unproven. Secondaries or sesquinaries from a large but unknown crater elsewhere on Triton are a distinct alternative.

Discovery and Follow-up of a Quasiperiodically Nulling and Subpulse Drifting Pulsar with the Murchison Widefield Array

The phenomenon of pulsar nulling, where pulsars temporarily and stochastically cease their radio emission, is thought to be indicative of a “dying” pulsar, where radio emission ceases entirely. Here we report the discovery of a long-period pulsar, PSR J0452−3418, from the ongoing Southern-sky MWA Rapid Two-meter pulsar survey. The pulsar has a rotation period of ∼1.67 s and a dispersion measure of 19.8 pc cm−3, and it exhibits both quasiperiodic nulling and subpulse drifting. Periodic nulling is uncommon, reported in only <1% of the pulsar population, with even a smaller fraction showing periodic nulling and subpulse drifting. We describe the discovery and follow-up of the pulsar, including a positional determination using high-resolution imaging with the upgraded Giant Metrewave Radio Telescope (uGMRT), initial timing analysis using the combination of Murchison Widefield Array (MWA) and uGMRT data, and detailed characterization of the nulling and drifting properties in the MWA’s frequency band (140–170 MHz). Our analysis suggests a nulling fraction of 34% ± 6% and a nulling periodicity of 42−1.3+1.5 pulses. We measure the phase (P 2) and time modulation (P 3) caused by the subpulse drifting, with an average P 2 of 7.1 −3.1+26.3 degrees and a P 3 of 4.8 −0.9+1.5 pulses. We compare and contrast the observed properties with those of other pulsars that exhibit subpulse drifting and quasiperiodic nulling phenomena, and find that the majority of these objects tend to be in the “death valley” in the period–period derivative (P– Ṗ ) diagram. We also discuss some broader implications for pulsar emission physics and the detectability of similar objects using next-generation pulsar surveys.