134125 research outputs found
Sort by
Stable isotope analysis reveals resource use by rays in an Australian temperate estuary
No full textEstuarine ecosystems are increasingly threatened by anthropogenic activities that deplete or replace natural habitats. This may lead to cascading effects in estuarine food webs as the availability of primary producers changes. Rays are ecosystem engineers that feed in sedimentary environments, yet their main prey items and the primary producers supporting their nutrition are unknown. The aim of this study was to assess resource use of two ray species in Wallis Lake, New South Wales, Australia, the estuary stingray (Hemitrygon fluviorum) and the common stingaree (Trygonoptera testacea). Using stable isotope analysis and Bayesian mixing models, we evaluated the contribution of likely prey and primary producers that contribute to the nutrition of these rays. Our results from Bayesian mixing models revealed that filter-feeders, including oysters, contributed negligibly to the assimilated diet of both ray species (estuary stingray: 5 ± 4%, common stingaree: 8 ± 6%). Benthic fish and crustaceans contributed 37 ± 10% and 28 ± 11%, respectively, in average to the diet of the estuary stingray, whereas Nassarius gastropods contributed 27 ± 11% to the diet of the common stingaree. Both species relied primarily on particulate organic matter for nutrition (estuary stingray: 46 ± 7%, common stingaree: 49 ± 9%). We estimated the trophic positions of the estuary stingray (3.60 ± 0.51) and the common stingaree (3.76 ± 0.50). We also assessed the isotopic niche of the estuary stingray relative to a common estuarine mesopredator, yellowfin bream (Acanthopagrus australis). Bayesian ecological niche modelling showed disproportionate overlap between the two species, with 72.1% of the estuary stingray's niche overlapping with that of the yellowfin bream, whereas only 35.2% of the yellowfin bream's isotopic niche overlapping with that of the estuary stingray. The estuary stingray also occupied a smaller niche (147.44 ± 40.25) compared to the yellowfin bream (339.61 ± 107.50), indicating that the estuary stingray may be more vulnerable to environmental perturbations that impact its sources of prey. This study highlights the resource use of two estuarine ray species and provides valuable insights for estuary managers regarding the potential impacts of future estuary modifications and aquaculture development on nutrient sources, benthic communities and the implications for these mesopredators. Future work should apply additional complementary dietary study methods (e.g. stomach content analysis, prey availability) to confirm estuary stingray vulnerability.No Full Tex
Expert agreement on key elements of transformational adaptation to climate risks
No full textTransformational adaptation (TA) to climate risks has gained broad interest. While existing case studies and frameworks discuss key dimensions and elements that constitute TA to distinguish it from ‘business as usual’ or ‘incremental’ adaptation, a universally accepted definition of the concept remains elusive. Here we used a three-round Delphi study with experts from across the globe, to ascertain the level of agreement on key elements of TA, and to assess differences across expert types, geographical focus and administrative levels. We find broad agreement on 13 elements that are important in a definition of TA: root causes, climate resilience, time-horizon, diversity of knowledge, depth of change, distributive justice, context specificity, multiscale, restructuring, persistence, maladaptation, avoiding lock-ins and systemic change. However, notable differences exist in what expert subgroups value as important elements. Clarifying what TA entails is crucial for developing effective policies and strategies, ensuring meaningful progress in addressing climate change.No Full Tex
Observational research in critical care: Harnessing the lens of truth
No full textCritical care is one of the most complex, high-stakes healthcare environments, with many elements of critical care practice invisible to scrutiny. Research that seeks to measure the what, to predict outcomes and establish cause and effect are important in critical care; but so too is research that seeks to explore and understand the who, the why, and the human experience.No Full Tex
Adaptive feature selection-based feature reconstruction network for few-shot learning
No full textFew-shot learning (FSL) aims to accurately classify samples of different categories using extremely limited training data. In this work, we thoroughly analyze the fact that existing FSL methods ignore the differences, even significant differences, in feature representations extracted by different base backbones from each input image, which in turn affect classification performance. Therefore, a novel automatic feature selection (AFS) module is designed which has the capability to consistently obtain high-quality feature representations from each input image across different datasets and integrate quantized local and global features extracted from different base backbones using adaptive weights. Furthermore, the designed AFS module has the capability to effectively highlight the target feature information, suppress the influence of background noise, and improve the quality of feature representations. Then a novel AFS-based feature reconstruction (AFS-FR) network is proposed for performing different FSL tasks. Extensive experiments conducted on five benchmark datasets (i.e., CUB-200-2011, Stanford Dog, Mini-ImageNet, Tiered-ImageNet, and Aircraft) demonstrate the effectiveness and superiority of the proposed AFS-FR method over state-of-the-art approaches. Especially in the Tiered-ImageNet dataset, the classification accuracies of the proposed AFS-FR method under the 5-way 1-shot and 5-way 5-shot experimental settings are 86.30±0.13 and 94.84±0.06 respectively, which achieve about 4 % and 5 % improvement than the best performance indicators in the comparison methods respectively.No Full Tex
A storm is born: immune activation and pathogenesis in arthritogenic alphavirus infections
Get PDFArthritogenic alphaviruses, including chikungunya (CHIKV), Ross River, and Mayaro viruses, are emerging global viruses responsible for causing arthralgia and chronic arthritis. Following mosquito-borne transmission, they quickly initiate infection in the skin, including in resident immune cells, and disseminate systemically into musculoskeletal tissues. The innate immune system responds rapidly through the activation of interferons, the production of inflammatory cytokines, and the recruitment of monocytes, macrophages, neutrophils, and dendritic cells, while the adaptive immune response, particularly virus-specific T and B cells, is critical for viral clearance. However, excessive immune activation can lead to both acute and chronic musculoskeletal pain through cytokine storm, tissue damage, and supporting immunopathology. Additionally, viral persistence and immune evasion may contribute to the development of chronic synovitis and cartilage degradation, leading to persistent joint pain. Despite recent advances, antiviral treatments remain unavailable, and to date, there is only one vaccine licensed (VIMKUNYA™ in 2025, against CHIKV), underscoring the urgent need for further research. This review explores the complex interplay between host immune responses and viral factors that lead from acute infection to chronic inflammation. Furthermore, it highlights key gaps in understanding viral persistence and immune evasion, and how to predict chronic diseases to improve therapeutic and preventive strategies against arthritogenic alphaviruses.Full Tex
A Novel Differentially Private Implicit Recommendation Algorithm Based on Gradient Perturbation Optimization
No full textWith the explosive growth of digital data, recommendation systems (RSs) play a crucial role in alleviating the problem of information overload. Implicit feedback data has become the primary data source for training recommendation models because of its richness and ease of collection. Leveraging such data for personalized recommendation services requires a large amount of user historical interactions, which poses serious privacy risks. Differential privacy (DP) has been integrated into implicit recommendation algorithms to protect user privacy. However, due to the inherent characteristics of implicit feedback, the current studies still have certain deficiencies in terms of data utility and privacy level. To this end, this article proposes a novel differentially private implicit recommendation algorithm. It integrates the Bayesian personalized ranking (BPR) matrix factorization (MF) with the Gaussian mechanism in Rényi DP (RDP) and designs an optimization strategy based on the binary index tree (BIT) to alleviate the cumulative errors. The proposed method not only can effectively capture the user preferences from sparse implicit feedback data by maximizing the posterior probability of rankings but also can more precisely manage the privacy budget allocation according to the query matrix. The theoretical analyses prove that the proposed method can satisfy the privacy guarantee and give the upper bound of privacy loss. The experimental results show that our method outperforms several existing advanced methods. It achieves a maximum performance improvement of 6.5% and 6.9% on Hit Rate (HR@10) and Normalized Discounted Cumulative Gain (NDCG@10) at a low privacy budget, which indicates that it can provide good recommendation quality while ensuring a strict privacy level.No Full Tex
An interdisciplinary analysis of recreational birdwatching and wetland extent in the Murray-Darling Basin, Australia
Get PDFTo fulfill obligations under the Ramsar Convention and achieve the objectives of a National Biodiversity Strategy, the Australian Government has committed to improving the ecological characteristics of wetlands across the continental Murray-Darling Basin, Australia’s largest surface water resource. Allocating a portion of an increasingly climate-constrained water resource to environmental flows for this purpose necessitates careful evaluation of environmental and economic benefits. We combined a large citizen science dataset of birdwatching visitation over 72 consecutive months at ten Basin wetland birdwatching hotspots with spatio-temporal data on site-specific proxies of environmental and ecological condition. Using an interdisciplinary combination of regression analysis, citizen science data, an online birdwatchers’ survey and in-depth birdwatcher interviews, we found that improved ecological condition was associated with increased birdwatcher visitation. Our findings contribute to the policy debate by identifying increased birdwatching visitation and related expenditure as potential co-benefits of improving ecological condition at Basin wetland birdwatching hotspots.Full Tex
Terminal Pleistocene ochre use at Fodongdi Cave, southwestern China
No full textThe gathering and use of ochre is a common behavior documented among Late Pleistocene human populations across the globe. Yet ochre use in the Paleolithic archaeological record of China remains poorly understood. Here we report on 36 pieces of ochre and 21 lithic artifacts with ochre residues from the archaeological deposits in Fodongdi Cave, Yunnan Province. These ochre finds, recovered from a succession of well-dated stratigraphic layers, offer an opportunity to discuss ochre use during the terminal Pleistocene in southwest China between 18,400 and 14,000 cal BP. We characterized the ochre assemblage using a combination of optical microscopy, thin section analysis, portable X-ray fluorescence, laser-induced breakdown and Raman spectrographic techniques, alongside scanning electron microscopy (with energy-dispersive X-ray spectroscopy). Results indicate at least three petrographic and chemically distinct groups of locally available ochre were used (presumably as red pigments). The ochre assemblage contains 27 pieces with clear anthropogenic modification including microstriations within grooves, parallel striations with polish, as well as smoothed areas with microstriations and luster. Use-wear traces and ochre residues on processing tools indicates that ochre was ground on grindstones and rubbed on soft materials, with quartzite pebbles used to process ochre before the pebbles were themselves flaked (used for tool stone). The Fodongdi Cave study provides novel information for southern China, suggesting the selection of local ochre sources, their processing directly onto grindstones and by rubbing against soft surfaces such as hide or human skin at the site, and the collection and use of different proportions of (local) ochres during the terminal Pleistocene.No Full Tex
Seismic response study of photovoltaic slopes considering soil plastic modulus evolution under far-field long-period ground motions
No full textAs the deployment of photovoltaic (PV) power stations on slopes becomes increasingly prevalent, the seismic safety of PV slopes along expressways has garnered significant attention. However, existing designs frequently overlook the effects of far-field long-period (FFLP) ground motions on the degradation of soil plastic modulus and cumulative damage. Taking a real-world expressway PV slope as a case study, this paper systematically investigates the dynamic response of PV slopes under ordinary ground motions (OGM), far-field non-harmonic ground motions (FNHM), and far-field harmonic ground motions (FHM). The study utilizes the P2PSand generalized bounding surface plasticity constitutive model and employs a pile-soil coupled implicit numerical method. The constitutive model was calibrated via direct simple shear (DSS) tests to accurately capture the cyclic nonlinear behavior of the soil. The research focuses on quantifying the differential impacts of varying ground motion characteristics on soil plastic modulus, effective stress, shear strain increments, and displacement deformation. The results indicate that the long duration and low-frequency characteristics of FFLP lead to significant cumulative damage; even at a lower peak acceleration (0.10 g), the induced slope displacement exceeds that caused by high-amplitude (0.40 g) OGM. In particular, FHM, characterized by quasi-harmonic features, significantly accelerates the degradation of plastic modulus and cumulative damage in shallow soil layers due to its frequent periodic characteristics and continuous narrow-band energy input, resulting in excessive permanent displacement of both the slope and the PV structure.No Full Tex
Resilience Enhancement of an Urban Rail Transit Network by Jointly Optimizing Restoration Sequences and Bus Bridging Services
No full textEnhancing the urban rail transit network (URT) resilience under disruptions is crucial for improving its ability to respond to such events. However, prior studies have rarely enhanced the URT network resilience by jointly optimizing the restoration sequences of failed components and bus bridging services (BBSs). To address this gap, a URT network resilience enhancement strategy combining a restoration sequence and extended BBS optimization (ESCRB strategy) is developed herein to improve the URT network resilience under disruptions. The real-world Chengdu subway network is utilized as an example to validate the effectiveness of the proposed ESCRB strategy. Results imply that the travel weight between stations is critical in assessing the network resilience. The proposed ESCRB strategy can effectively enhance the URT network resilience by simultaneously optimizing restoration sequences and extended BBSs. After employing the ESCRB strategy, the network resilience metrics under random and deliberate disruptions are decreased by 83.96% and 81.80%, respectively. Finally, a sensitivity analysis is conducted to discuss the impact of parameters on the effectiveness of the formulated ESCRB strategy, and some practical implications are provided to improve the URT network resilience.No Full Tex