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The propagation of elastic-flexural–gravity waves through an ice shelf is modeled using full three-dimensional elastic models that are coupled with a treatment of under-shelf sea-water flux: (i) finite-difference model (Model 1), (ii) finite-volume model (Model 2) and (iii) depth-integrated finite-difference model (Model 3). The sea-water flow under the ice shelf is described by a wave equation involving the pressure (the sea-water flow is treated as a “potential flow”). Numerical experiments were undertaken for an ice shelf with ‘rolling’ surface morphology, which implies a periodic structure of the ice shelf. The propagation of ocean waves through an ice shelf with rolling surface morphology is accompanied by Bragg scattering (also called Floquet band insulation). The numerical experiments reveal that band gaps resulting from this scattering occur in the dispersion spectra in frequency bands that are consistent with the Bragg’s law. Band gaps render the medium opaque to wave, that is, essentially, the abatement of the incident ocean wave by ice shelf with rolling surface morphology is observed in the models. This abatement explains the ability of preserving of ice shelves like the Ward Hunt Ice Shelf, Ellesmere Island, Canadian Arctic, from the possible resonant-like destroying impact of ocean swell.
Condensed mathematics, developed by Clausen and Scholze over the last few years, proposes a generalization of topology with better categorical properties. It replaces the concept of a topological space by that of a condensed set, which can be defined as a sheaf for the coherent topology on a certain category of compact Hausdorff spaces. In this case, the sheaf condition has a fairly simple explicit description, which arises from studying the relationship between the coherent, regular, and extensive topologies. In this paper, we establish this relationship under minimal assumptions on the category, going beyond the case of compact Hausdorff spaces. Along the way, we also provide a characterization of sheaves and covering sieves for these categories. All results in this paper have been fully formalized in the Lean proof assistant.
To describe the use of cultures for acid-fast bacilli (AFB) and situations in which AFB cultures are unlikely to be of clinical benefit.
Design:
Retrospective descriptive study of AFB cultures submitted to Sentara Health microbiology laboratory from December 1, 2021, to December 1, 2023. Data were collected from the electronic medical record and included patient demographics, the service line that ordered the culture, specimen source, and culture results.
Setting:
Sentara Healthcare System.
Patients:
All patients who had specimens submitted to the microbiology laboratory during the study period were included.
Results:
A total of 13,944 AFB cultures from 8,243 patients were collected during the study period. Of these, 4.72% (n = 389) patients had a positive result, and 40 of 680 positive cultures were likely contaminants or non-mycobacterial. The average number of days between culture collection and positive results was 84.32 days (SD = 49.64) and 56.25 days (SD = 8.32) for negative results. Most cultures were ordered by medical subspecialties (44.06%, n = 6,144), followed by orthopedic providers (23.34%, n = 3,254) and surgical subspecialty providers (16.11%, n = 2,246). Most specimens were pulmonary (n = 6,620) with 619 (9.35%) positive cultures. Of 3,561 AFB cultures ordered from bone specimens, only 17 were positive (0.48%). The number of specimens processed by the microbiology laboratory required 2 full-time microbiology technicians to process specimens.
Conclusions:
Many AFB cultures were sent from patients who did not have clinical scenarios consistent with mycobacterial disease and cultures were not clinically indicated. Implementation of testing criteria could decrease AFB cultures and healthcare costs.
We present a re-discovery of G278.94+1.35a as possibly one of the largest known Galactic supernova remnants (SNRs) – that we name Diprotodon. While previously established as a Galactic SNR, Diprotodon is visible in our new Evolutionary Map of the Universe (EMU) and GaLactic and Extragalactic All-sky MWA (GLEAM) radio continuum images at an angular size of $3{{{{.\!^\circ}}}}33\times3{{{{.\!^\circ}}}}23$, much larger than previously measured. At the previously suggested distance of 2.7 kpc, this implies a diameter of 157$\times$152 pc. This size would qualify Diprotodon as the largest known SNR and pushes our estimates of SNR sizes to the upper limits. We investigate the environment in which the SNR is located and examine various scenarios that might explain such a large and relatively bright SNR appearance. We find that Diprotodon is most likely at a much closer distance of $\sim$1 kpc, implying its diameter is 58$\times$56 pc and it is in the radiative evolutionary phase. We also present a new Fermi-LAT data analysis that confirms the angular extent of the SNR in gamma rays. The origin of the high-energy emission remains somewhat puzzling, and the scenarios we explore reveal new puzzles, given this unexpected and unique observation of a seemingly evolved SNR having a hard GeV spectrum with no breaks. We explore both leptonic and hadronic scenarios, as well as the possibility that the high-energy emission arises from the leftover particle population of a historic pulsar wind nebula.
Engineering machines are becoming increasingly complex and possess more control variables, increasing the complexity and versatility of the control systems. Different configurations of the control system, named a policy, can result in similar output behavior but with different resource or component life usage. There is therefore an opportunity to find optimal policies with respect to economic decisions. While many solutions have been proposed to find such economic policy decisions at the asset level, we consider this problem at the fleet level. In this case, the optimal operation of each asset is affected by the state of all other assets in the fleet. Challenges introduced by considering multiple assets include the construction of economic multi-objective optimization criteria, handling rare events such as failures, application of fleet-level constraints, and scalability. The proposed solution presents a framework for economic fleet optimization. The framework is demonstrated for economic criteria relating to resource usage, component lifing, and maintenance scheduling, but is generically extensible. Direct optimization of lifetime distributions is considered in order to avoid the computational burden of discrete event simulation of rare events. Results are provided for a real-world case study targeting the optimal economic operation of a fleet of aerospace gas turbine engines.
In this study, the results obtained using GOES satellite X-ray data and MWO and WSO measurements of the solar magnetic field between 1976 and 2022 are compared and discussed. By analysing GOES satellite X-ray data in 47 different time periods of one month long, 7 500 solar flares are obtained, the flare equivalent duration distributions against the total duration of the flare are statistically modelled, and then their variation via time is examined. The variations of the model parameters such as the Plateau, which is considered as an indicator of the stellar saturation level in an observation season, and the flare timescales via time are examined. We noticed that the variation found in the solar magnetic field and the variation determined in the flare saturation levels are very similar. As a result, it is well known that the solar magnetic dipole moment measured from the solar poles steadily decreased from 1976 to 2022. We revealed that the solar X-ray flare energies are also generally decreasing in the same trend. This decrease is also evident in flare timescales, indicating that the geometry of solar magnetic loops is getting smaller over time.
Urine cultures ordered for patients with indwelling urinary catheters might lead to reporting of non-clinically significant catheter-associated urinary tract infections (CAUTIs) or asymptomatic bacteriuria to the National Healthcare Safety Network (NHSN). We examined factors associated with inappropriate urine cultures orders leading to reporting of non-clinically significant CAUTIs to NHSN.
Although non-monetary benefits remain an important component of most workers’ wages in today's industrial economies, development economists and economic historians tend to view such payments as a remnant of older, obsolete labour regimes. But when in-kind wages are assumed to be exploitative, an outcome of market inefficiencies, or simply the result of limited supply of coinage, their actual economic functions can be obscured. Once we drop the constraints imposed by such assumptions and look at the historical evidence, we are forced to confront the possibility that workers actually used them to their advantage.
In this article, I analyse how in-kind wages functioned in certain historical contexts, and conclude that available explanations are far too limited. As the historical cases studied show, the different forms of in-kind payments must be examined because those forms – not just overall wage levels – helped determine labour supply, social and occupational mobility, and even capital formation.
The goods and services that made up in-kind payments also provide a fuller understanding of gender wage gaps. Non-monetary wages gave workers options that cash wages did not, and so created and reproduced fundamental inequalities among different groups.
In the aftermath of the 2022 Pakistan flooding, disaster management faced critical challenges, particularly in mental health support. This study analyzed an incident where eighteen internally displaced individuals lost their lives in a bus fire. The current approach involves a comprehensive analysis of the incident, exploring the difficulties encountered in managing relief efforts, and providing mental health support. The study aims were to evaluate existing mental health support mechanisms, to identify challenges in disaster management, and to propose recommendations for future preparedness. Recommendations include enhancing disaster response training, integrating mental health services into primary health care, and prioritizing community resilience. These insights contribute to a deeper understanding of disaster management in resource-constrained regions.
The southern African shrub boneseed [Chrysanthemoides monilifera subsp. monilifera (L.) Norl.] is a perennial shrub that is a significant threat to natural ecosystems and is listed as a Weed of National Significance in Australia. In Western Australia (WA) it has spread across peri-urban and natural environments. We assembled a single standardized database containing more than 2,050 presence records for individual plants and 135 absence records at a local population level. We further refined the populations into 89 sites that require different management trajectories due to topography and capacity of land managers to implement control. Forty-nine of these sites were in urban regions and 40 sites were in regional WA. We split these 89 sites into three near-term management goals: watch (12), extirpate (68), and contain (9). The 12 watch sites are those where all available evidence suggests that there have been no new inputs into the seedbank for 15 yr. The 68 sites marked for extirpation are those where delimitation is already achieved or easily achievable, where there have been minimal seed inputs into the soil seedbank in recent years due to consistent surveillance and control, and where surveys for new plants are likely to be efficient to conduct. Finally, for nine sites in urban regions around Perth, we recommend containment in the near term with a longer-term goal to achieve delimitation and extirpation. To achieve the objective of state-level eradication, a coordinated and sustained campaign involving three components—delimitation of all sites, prevention of further inputs into the soil seedbank, and systematic field surveys to remove plants—must commence without delay. While resourcing requirements for delimitation and overall program management are not possible to estimate, our prior experience suggests that it will take at least 1,900 h of on-ground surveying by experienced personnel to achieve extirpation of C. monilifera subsp. monilifera in WA.
Early modern local chronicles are a largely neglected, yet stable genre of texts that can be used for comparative research over time and space. The NWO-funded research project Chronicling Novelty (2018–24) investigated the reception of new media and new knowledge among early modern chroniclers in the Low Countries. For this purpose, we created a digitized corpus of 204 Dutch-language chronicles from the period 1500–1850. This article presents the methodological decisions made in creating this corpus and their implications for its representativeness. The second part examines the social, religious and political profile of the chroniclers: who wrote chronicles and what does this reveal about chronicling as a cultural and social practice? Particularly interesting in this respect is how the chroniclers’ strong involvement in local public affairs authorized their chronicling practices, and vice versa.
Hypereutrophic Grand Lake St Marys (GLSM) is a large (52 km2), shallow (mean depth ~ 1.5 m) reservoir in an agricultural watershed of western Ohio (USA). GLSM suffers from extensive cyanobacterial harmful algal blooms (cHABs) that persist much of the year, resulting in total microcystin concentrations that are often above safe contact levels. Over two summers (2020 and 2021), two phosphorus (P) binding agents (alum and lanthanum/bentonite clay Phoslock, respectively), in conjunction with a P-binding algaecide (SeClear) in 2021, were applied to a 3.24-ha enclosure to mitigate cHAB activity and create a ‘safe’ recreational space for the public. We evaluated these applications by comparing total phosphorus (TP), total microcystin, total chlorophyll, and phycocyanin concentrations within the enclosure and the adjacent lake. Some evidence for short-term reductions in TP, microcystin, chlorophyll, and phycocyanin concentrations were observed following each P binding treatment, but all parameters rapidly returned to or exceeded pre-application levels within 2–3 weeks after treatment. These results suggest that in-lake chemical treatments to mitigate cHABs are unlikely to provide long-lasting benefits in these semi-enclosed areas of large, shallow, hypereutrophic systems, and resources may be better applied toward reducing external nutrient loads (P and nitrogen) from the watershed.
The regent honeyeater Anthochaera phrygia is a Critically Endangered Australian songbird, with current population estimates of < 300 individuals remaining in the wild. Low nest success is a factor preventing the recovery of the population, and management remedies are needed. However, a lack of data on intervention success raises uncertainty and impedes planning. To identify management priorities under uncertainty, we engaged with conservation practitioners and key stakeholders to develop and evaluate potential nest protection interventions. Four categories of threats were considered: avian predators, mammalian predators, extreme weather events and avian competitors. The interventions with the highest predicted probabilities of nest success under each threat category were, respectively: lethal control of avian predators, the use of tree collars to control arboreal mammalian predators, the provisioning of supplementary food and nesting resources during extreme weather events, and control of the noisy miner Manorina melanocephala, a competitor species. Our analysis shows that by applying a combination of conservation actions alongside improvements in nest detection, it is possible, based on the opinion of experts, to provide a pathway for the recovery of the regent honeyeater.
Word embeddings are now a vital resource for social science research. However, obtaining high-quality training data for non-English languages can be difficult, and fitting embeddings therein may be computationally expensive. In addition, social scientists typically want to make statistical comparisons and do hypothesis tests on embeddings, yet this is nontrivial with current approaches. We provide three new data resources designed to ameliorate the union of these issues: (1) a new version of fastText model embeddings, (2) a multilanguage “a la carte” (ALC) embedding version of the fastText model, and (3) a multilanguage ALC embedding version of the well-known GloVe model. All three are fit to Wikipedia corpora. These materials are aimed at “low-resource” settings where the analysts lack access to large corpora in their language of interest or to the computational resources required to produce high-quality vector representations. We make these resources available for 40 languages, along with a code pipeline for another 117 languages available from Wikipedia corpora. We extensively validate the materials via reconstruction tests and other proofs-of-concept. We also conduct human crowdworker tests for our embeddings for Arabic, French, (traditional Mandarin) Chinese, Japanese, Korean, Russian, and Spanish. Finally, we offer some advice to practitioners using our resources.
Employee voice and silence research shows workers’ ability to express dissatisfaction is impeded by a range of factors. This paper focuses on two: the power asymmetry inherent in the employment relationship, and work context. It examines early career academics (ECAs) – mainly doctoral students, associate lecturers, and assistant professors – many of whom are immersed in atypical, employment or employment-like relationships that are frequently experienced as disempowering. A scoping review provides a frame for understanding ECA voice and silence. It finds there is little on ECAs in the employee voice and silence literature. However, broader concepts of voice and silence are discussed in higher education research on doctoral students and other types of ECAs. Complex work arrangements, difficult supervisory relationships, and hierarchical norms stifle ECA voice. Supervision conceptualised as co-created ‘critical friendship’ facilitates voice. Studies that expand knowledge of ECA voice and silence are recommended, especially as concerns about ECA wellbeing grow.
This paper proposes to solve the vortex gust mitigation problem on a 2D, thin flat plate using onboard measurements. The objective is to solve the discrete-time optimal control problem of finding the pitch rate sequence that minimizes the lift perturbation, that is, the criterion where is the lift coefficient obtained by the unsteady vortex lattice method. The controller is modeled as an artificial neural network, and it is trained to minimize using deep reinforcement learning (DRL). To be optimal, we show that the controller must take as inputs the locations and circulations of the gust vortices, but these quantities are not directly observable from the onboard sensors. We therefore propose to use a Kalman particle filter (KPF) to estimate the gust vortices online from the onboard measurements. The reconstructed input is then used by the controller to calculate the appropriate pitch rate. We evaluate the performance of this method for gusts composed of one to five vortices. Our results show that (i) controllers deployed with full knowledge of the vortices are able to mitigate efficiently the lift disturbance induced by the gusts, (ii) the KPF performs well in reconstructing gusts composed of less than three vortices, but shows more contrasted results in the reconstruction of gusts composed of more vortices, and (iii) adding a KPF to the controller recovers a significant part of the performance loss due to the unobservable gust vortices.
I develop a survey method for estimating social influence over individual political expression, by combining the content-richness of document scaling with the flexibility of survey research. I introduce the “What Would You Say?” question, which measures self-reported usage of political catchphrases in a hypothetical social context, which I manipulate in a between-subjects experiment. Using Wordsticks, an ordinal item response theory model inspired by Wordfish, I estimate each respondent’s lexical ideology and outspokenness, scaling their political lexicon in a two-dimensional space. I then identify self-censorship and preference falsification as causal effects of social context on respondents’ outspokenness and lexical ideology, respectively. This improves upon existing survey measures of political expression: it avoids conflating expressive behavior with populist attitudes, it defines preference falsification in terms of code-switching, and it moves beyond trait measures of self-censorship, to characterize relative shifts in the content of expression between different contexts. I validate the method and present experiments demonstrating its application to contemporary concerns about self-censorship and polarization, and I conclude by discussing its interpretation and future uses.
In cross-linguistic word learning, learning new knowledge based on existing knowledge is a common and lifelong process. This study investigated whether inhibitory control would be conducive to this process. We asked Chinese-English bilinguals to learn new meanings for familiar English ambiguous words within two consecutive days, manipulating semantic relatedness and word frequency to create four categories: high-frequency-unrelated, high-frequency-related, low-frequency-unrelated and low-frequency-related ambiguous words. Participants completed translation recognition and production tests immediately after learning and again one week later, with flanker and stop-signal tasks interspersed to measure their interference inhibition and response inhibition. The results indicated that inhibitory control, particularly interference inhibition, significantly aided in learning new meanings when direct knowledge transfer from existing knowledge was unfeasible. This research enhances our comprehension of individual differences in word learning, offering valuable perspectives for broader theories of word learning and targeted educational interventions.
In this paper, we present the new results of the U–Pb age dating and Lu-Hf isotopic analysis of detrital zircons of the four representative metasedimentary rock samples from the Mongol Altai Group, Mongolian part of the Altai-Mongolian terrane. Our new results indicate that the metasedimentary rocks of the Mongol Altai Group were formed after ∼497 Ma, Late Cambrian and deposited during the Early-Middle Ordovician. The detrital zircons of four samples yield a two major age peaks at 503–517 Ma, and 775–843 Ma, respectively, with minor involvement of older zircons. The nearby Lake Zone of Ikh-Mongol Arc most likely provided plenty of Early Paleozoic materials, the subdominant Neoproterozoic detrital zircons could be supplied by the felsic intrusions along the western margin of the Tuva-Mongol microcontinent, and the sparse older zircons may be derived from its basement. With combination of previous studies in the Chinese Altai, Russian Altai and Hovd terrane, our data suggest that the Altai–Mongolian terrane possibly represents a coherent continental arc-accretionary prism system built upon the active margin of the western Mongolia during the Cambrian to Ordovician. Moreover, the dominant Neoproterozoic to Early Paleozoic detrital zircons from the Mongol Altai sequence yield largely varied εHf(t) values from −17.4 to +12.0, indicating that input juvenile material and reworking of crustal components are both important in the accretionary orogenesis. A compilation of U–Pb and Hf isotope data of detrital zircons shows that the source area underwent two most extensive magmatic activities at ca. 470–574 Ma and 687–967 Ma, respectively.