Warning Signals Research Articles

Research on Port Risk Assessment Based on Various Meteorological Disasters

Within the framework of economic globalisation, ports serve as critical junctures in international trade and play a vital role. However, as infrastructure is closely linked to the natural environment, ports are highly susceptible to the impacts of meteorological disasters. Therefore, a comprehensive assessment of the risks posed by meteorological hazards to ports, establishing corresponding early warning mechanisms, and adopting reasonable response and recovery strategies, is paramount in ensuring the safe operation of ports and maintaining the stability of international trade. This study has comprehensively analysed historical data and identified the pre-established loss stratification system, improving the theoretical construct of “expected loss”. Additionally, this research has innovatively integrated the idea of preventative factors aligned with risk indicators. A quantitative algorithm was used to factor in the preventative factors within the computational procedure, deriving the weights pertinent to each risk indicator. This research aimed to reduce the subjectivity inherent in the weighting assignment process through such an approach, thereby enhancing disaster risk assessment’s scientific rigour and reliability. Moreover, it underscores the critical role of adaptive urban planning in enhancing the resilience of crucial economic nodes like ports, thereby contributing to the broader objectives of sustainable urban development.

Stochastic response of ultrasensitivity: Optimized switching of mitogen activated protein kinase (MAPK) cascade

The intricate dynamics of ultrasensitive transitions within mitogen-activated protein kinase (MAPK) cascade circuits regulate the diverse physiological activities in a living organism emphasizing their pivotal role in cellular signal transduction. We have shown that the generic features of ultrasensitive transition often characterized through critical slowing down, however, one can have a theoretical estimate of such catastrophic transition using a stochastic response function, called early warning signals (EWS). EWS is composed of slowing down of decay of correlation and divergence of fluctuation phenomenon under very low perturbation. It is shown that the ultrasensitive transition arises depending on the trade off between the cycle number and essential activation parameter. Therefore, the transition point is kinetically optimized by these two parameters so that a high activation energy is surmounted through multiple steps and here we have shown that EWS as stochastic response functions can capture this optimization most effectively.

Ammonia-Responsive Colorimetric Film of Phytochemical Formulation (Alizarin) Grafted onto ZIF-8 Carrier with Poly(vinyl alcohol) and Sodium Alginate for Beef Freshness Monitoring.

In this study, we devised a photothermally stable phytochemical dye by leveraging alizarin in conjunction with the metal-organic framework ZIF-8 (AL@ZIF-8). The approach involved grafting alizarin into the microporous structure of ZIF-8 through physical adsorption and hydrogen-bonding interactions. AL@ZIF-8 significantly enhanced the photostability and thermostability of alizarin. The nanoparticles demonstrate substantial color changes in various pH environments, showcasing their potential for meat freshness monitoring. Furthermore, we introduced an intelligent film utilizing poly(vinyl alcohol)-sodium alginate-AL@ZIF-8 (PA-SA-ZA) for detecting beef freshness. The sensor exhibited a superior water contact angle (52.34°) compared to the alizarin indicator. The color stability of the film was significantly enhanced under visible and UV light (ΔE < 5). During beef storage, the film displayed significant color fluctuations correlating with TVB-N (R2=0.9067), providing precise early warning signals for assessing beef freshness.

Diet, sexual dimorphism, and fertility aspects of Melanophryniscus fulvoguttatus (Mertens, 1937) from Central-East Brazil

Melanophryniscus fulvoguttatus is a small toad that inhabits the Cerrado, Atlantic Forest, and humid Chaco of South America. Due to its aposematic coloration and behavior, it is a species that may present chemical defenses such as alkaloids and a restricted diet similar to other species of the genus. Although it was described in the early 20th century, there is still little information on its natural history and ecology. Here, we described the diet, tested the sexual dimorphism, and calculated the fertility index of M. fulvoguttatus based on a sample of eight males and 21 females from a population within the Cerrado. Sexual dimorphism was assessed using 15 morphometric measures; diet was calculated as an index of relative importance by prey item and tested for sex differences; fertility was tested for relations between body size and the number of eggs; and we also estimated the reproductive investment. Our results demonstrate that this population’s diet consisted mostly of ant species, with Pheidole radoszkowskii being the most important, followed by Crematogaster sp. and Cyphomyrmex transversus. Regarding sexual dimorphism, we observed that females were significantly larger than males, with a positive relationship between female size and the number of eggs. We did not find significant differences in the diets of males and females. Although the diet and reproductive aspects of M. fulvoguttatus are similar to those of its congeneric species, further studies are needed in order to address the relationship between the species diet and its chemical defenses.

Longitudinal analysis of microcirculatory parameters in gingival tissues after tooth extraction in patients with different risk profiles for wound healing disorders – a pilot study

ObjectivesWe aimed to establish a risk profile for intraoral wound healing disorders based on measurements of microcirculation in gingival tissues.Materials and methodsOxygen saturation (SO2) and blood flow in gingival tissues were measured with tissue spectrometry and laser doppler spectroscopy in 37 patients before/after tooth extractions. Patients were assigned to four groups: anamnestically and periodontally healthy patients (n = 7), anamnestically healthy but suffering from periodontitis (n = 10), anamnestically healthy but smoking and suffering from periodontitis (n = 10) and suffering from diabetes and periodontitis (n = 10). Measurements were performed at three different time points: Baseline measurement (T0), one day post extractionem (p.e.) (T1) and seven days p.e. (T2).ResultsBaseline SO2 values were higher in control patients (p = .038). This effect was most evident in comparison to smokers suffering from periodontitis (p = .042), followed by diabetics suffering from periodontitis (p = .09). An opposite trend was seen for blood flow. Patients suffering from periodontitis demonstrated higher blood flow values (p = .012). Five patients, which belonged to the group of smokers suffering from periodontitis, showed clinically a delayed wound healing.ConclusionDifferences in SO2 and blood flow of gingival tissue could be detected in different groups of patients with existing periodontitis compared to control patients.Clinical RelevanceLower baseline SO2 values could be a warning signal for possible wound healing disorders after oral surgery.

Early warning signals of the termination of the African Humid Period(s)

The transition from a humid green Sahara to today’s hyperarid conditions in northern Africa ~5.5 thousand years ago shows the dramatic environmental change to which human societies were exposed and had to adapt to. In this work, we show that in the 620,000-year environmental record from the Chew Bahir basin in the southern Ethiopian Rift, with its decadal resolution, this one thousand year long transition is particularly well documented, along with 20–80 year long droughts, recurring every ~160 years, as possible early warnings. Together with events of extreme wetness at the end of the transition, these droughts form a pronounced climate “flickering”, which can be simulated in climate models and is also present in earlier climate transitions in the Chew Bahir environmental record, indicating that transitions with flickering are characteristic of this region.

High–low volatility spillover network between economic policy uncertainty and commodity futures markets

AbstractBased on the formation and evolution of systemic risk, we study the high‐low volatility spillovers between economic policy uncertainty (EPU) and commodity futures and identify the source of risk accumulation and risk outbreak, as well as the corresponding contagion mechanisms. Upon comparing topological characteristics on each volatility layer, our results demonstrate that high and low volatility spillover networks have different network characteristics and evolution behaviors. At the system level, high volatility spillovers are relatively stronger than spillovers in in low volatility network, while the risk propagation efficiency in the low volatility network is higher. At the market level, EPU is not only an important risk‐emitter but also a risk‐recipient most of the time. Additionally, compared with high volatility network, low volatility network characteristics have greater predictive ability for risk spillover among commodity futures, which means that it contains additional information and provides early warning signals for financial stress.

Effect of Total Assets, Capital Expenditure, Leverage, And GRDP to the Ratio of Regional Financial Independence in Nusa Tenggara Barat Province in 2018-2022

This study examines the effect of total assets, capital expenditure, leverage and PDRB on the ratio of district financial independence in NTB province in 2018-2022. Fiscal decentralization encourages to implement regional autonomy policies, namely giving authority to local governments to regulate finances in their respective regions. Tests were conducted on all districts in NTB province during 2018-2022. The results of this study indicate that total assets, capital expenditure and leverage have no significant effect on the financial independence of districts in NTB province. While PPDRB has a significant effect on the financial independence of districts in NTB province. The research findings indicate that the many or few assets owned by a region will not always affect regional financial independence, the allocation of inappropriate capital expenditures causes regional financial independence to decrease, and the use of capital expenditures to increase regional financial independence. total debt to equity ratio not used wisely, causing the level of regional financial independence to be low. The implications of this research provide warning signals to local governments to be more productive in managing regional wealth assets, allocating capital expenditures in accordance with the budget and on target, and more wisely in using capital expenditures debt to equity ratio local governments in order to increase regional financial independence.

Early warning for thermal runaway in lithium-ion batteries during various charging rates: Insights from expansion force analysis

Thermal runaway introduces a significant challenge in the widespread application of lithium-ion batteries, necessitating advanced early-warning technologies to ensure safety, particularly during charging. Only monitoring the temperature and voltage limit the performance of diagnostic algorithms. The expansion behavior of batteries, which is linked to their operating status, offers a vital indicator of safety. In this study, the evolution of multidimensional signals during overcharging experiments at different current rates is comprehensively investigated. The result shows that the abnormal expansion force can be detected at temperatures as low as 35.4 °C, which achieves an early warning signal 11 min earlier than the onset of battery thermal runaway. The effect of charging rate on battery safety is comprehensively analyzed, showing that the time interval between the warning signal of the expansion force and temperature increases steadily from 151 s to 682 s as the charging rate decreases. However, the charging rate hardly affects the stage of charge boundary of venting, which is around ±118 %. These insights are crucial for understanding early warning mechanisms in overcharged batteries, offering valuable guidance for enhancing the safety of electric vehicles and energy storage systems.

Selfish herd effects in aggregated caterpillars and their interaction with warning signals.

Larval Lepidoptera gain survival advantages by aggregating, especially when combined with aposematic warning signals, yet reductions in predation risk may not be experienced equally across all group members. Hamilton's selfish herd theory predicts that larvae that surround themselves with their group mates should be at lower risk of predation, and those on the periphery of aggregations experience the greatest risk, yet this has rarely been tested. Here, we expose aggregations of artificial 'caterpillar' targets to predation from free-flying, wild birds to test for marginal predation when all prey are equally accessible and for an interaction between warning coloration and marginal predation. We find that targets nearer the centre of the aggregation survived better than peripheral targets and nearby targets isolated from the group. However, there was no difference in survival between peripheral and isolated targets. We also find that grouped targets survived better than isolated targets when both are aposematic, but not when they are non-signalling. To our knowledge, our data provide the first evidence to suggest that avian predators preferentially target peripheral larvae from aggregations and that prey warning signals enhance predator avoidance of groups.

When aposematism is not enough: Exotic Rattus rattus shows no mercy for carcasses of Salamandra salamandra in insular populations.

Predator-prey interaction is a major force driving natural selection. Yet, the identification of species preying on, or consuming, aposematic species is largely unknown. Here, I conduct a study evaluating the role of the exotic Rattus rattus as a consumer and possible predator of the aposematic and toxic Salamandra salamandra. I used camera traps to investigate the response of R. rattus towards S. salamandra carcasses in two insular populations, Ons and San Martiño (NW Spain), which show remarkable contrasting behaviour (nocturnal vs. diurnal activity) and demographic and phenotypic differences. This study unveils R. rattus consumes S. salamandra despite its aposematic colour pattern and toxicity. The high number of salamander carcasses consumed or taken by rats throughout each island (90%-100%) and the lack of other possible predator-prey interactions points to R. rattus as an efficient consumer of S. salamandra in these insular environments, which might exert a high predation pressure on both islands. Yet, the drivers underlying the behavioural and phenotypic differences in these insular populations should be further investigated.

Behaviorally Inhibited Individuals Learn to Avoid Transdermal Stimulation More Quickly, and this Learning Is Accelerated Throughout the Study

Information on how behavioral inhibition (BI) affects the amount of time it takes an individual to avoid a stressful situation could answer many questions about anxiety disorders and whether BI influences avoidance behavior. BI is a temperament characteristic associated with increased vulnerability to stress compared to their non-behaviorally inhibited (NBI) counterparts. Our previous study demonstrated that BI individuals have lower heart rate variability (HRV) than NBI individuals. This suggests that BI individuals have significantly less parasympathetic nervous system (PNS) output at rest; however, it is unknown how BI affects avoidance acquisition using a mildly stressful stimulus. Previous studies have shown differences in the behavior found in Wistar-Kyoto rats, which exhibit BI behavior, compared to Sprague-Dawley control rats. Our current study will test the hypothesis that BI individuals learn to make escape and avoidance responses using subdermal ulnar nerve transdermal electrical stimulation (TES) more rapidly than NBI individuals and also experience a more significant increase in heart rate (HR) and blood pressure (BP). BI individuals were identified through a series of self-reported questionnaires. Three levels (30 mV, 50 mV, and 70 mV) of subdermal ulnar nerve TES were delivered to participants while receiving warning signals that predicted the delivery of the TES. Participants had access to a button that, when pressed during the light, prevented the delivery of the TES. This was scored as an avoidance response. If the button was pressed during the TES, it terminated the stimulation and was scored as an escape. HR and BP were also measured using a BIOPAC data acquisition system during TES. Our preliminary results indicate that BI individuals show a decrease in latency in the amount of time it took them to make an avoidance as the study progressed, while NBI individuals show a slight increase in latency, highlighting the idea that BI individuals are more curious to press the button or they are more likely to want to avoid the TES quicker. We would like to thank the Carthage College Research, Scholarship, and Creativity Committee as well as the Carthage College Neurophysiology Laboratory professors for their continued support throughout the study. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Artificial Intelligence and Machine Learning in Financial Services: Risk Management and Fraud Detection

The field of financial risk management is undergoing a significant transformation due to the advancements in artificial intelligence (AI) and the underlying machine learning (ML) techniques that provide the foundation of AI. These developments hold the potential to revolutionize the way the user’s approach and address financial risk. The expansion of AI-driven solutions has opened up various opportunities for comprehending and managing risk. These opportunities encompass a wide range of activities, such as determining appropriate lending amounts for customers in banking, issuing warning signals to financial market traders regarding position risk, identifying instances of customer and insider fraud, enhancing compliance efforts, and mitigating model risk. The prime objective of this study is to investigate the application of AI and ML in the Financial Services industry, with a specific focus on Risk Management and Fraud Detection. This study proposes an intelligent and distributed approach for detecting Internet financial fraud using Big Data. The methodology entails the utilization of the graph embedding algorithm Node2Vec for the purpose of acquiring knowledge and representing the structural characteristics of the financial network graph in the form of compact vectors with reduced dimensions. This facilitates the intelligent and effective categorization and forecasting of data samples from a dataset of significant magnitude through the utilization of a deep neural network. Based on the study's findings, it was observed that the F1-Score test outcomes obtained from the Node2Vec algorithm range from 67.1% to 73.4%. These results surpass the outcomes achieved by the other two algorithms used for comparison. This finding demonstrates that Node2Vec has greater stability in terms of overall performance and yields superior categorization outcomes.

Analysis of long transients and detection of early warning signals of extinction in a class of predator-prey models exhibiting bistable behavior.

In this paper, we develop a method of analyzing long transient dynamics in a class of predator-prey models with two species of predators competing explicitly for their common prey, where the prey evolves on a faster timescale than the predators. In a parameter regime near a singular zero-Hopf bifurcation of the coexistence equilibrium state, we assume that the system under study exhibits bistability between a periodic attractor that bifurcates from the singular Hopf point and another attractor, which could be a periodic attractor or a point attractor, such that the invariant manifolds of the coexistence equilibrium point play central roles in organizing the dynamics. To find whether a solution that starts in a vicinity of the coexistence equilibrium approaches the periodic attractor or the other attractor, we reduce the equations to a suitable normal form, and examine the basin boundary near the singular Hopf point. A key component of our study includes an analysis of the long transient dynamics, characterized by their rapid oscillations with a slow variation in amplitude, by applying a moving average technique. We obtain a set of necessary and sufficient conditions on the initial values of a solution near the coexistence equilibrium to determine whether it lies in the basin of attraction of the periodic attractor. As a result of our analysis, we devise a method of identifying early warning signals, significantly in advance, of a future crisis that could lead to extinction of one of the predators. The analysis is applied to the predator-prey model considered in Sadhu (Discrete Contin Dyn Syst B 26:5251-5279, 2021) and we find that our theory is in good agreement with the numerical simulations carried out for this model.

First comprehensive higher level phylogeny of Zygaenidae (Lepidoptera) including estimated ages of the major lineages and a review of known zygaenid fossils

AbstractZygaenidae, also known as burnet, forester, smoky, or leaf skeletonizer moths, are a family of mainly diurnal moths well known for their aposematic colouration and the ability to release hydrogen cyanide as a defence mechanism. So far, few attempts have been made to understand the evolutionary history of the global zygaenid fauna. Here, we inferred the most comprehensive molecular phylogeny for Zygaenidae to date and estimated the lineage timing‐of‐divergence with a Bayesian approach. Building on earlier work, we significantly increased the taxon and gene sampling for the family, which here included data from 30 gene fragments, recovered from public databases or newly sequenced, for almost 30% of the species representing 92 genera (49%) and all five subfamilies. We recovered strong support for the monophyly of Zygaenidae, Chalcosiinae, and Zygaeninae. Procridinae were recovered as monophyletic with low support, whereas the monophyly of Callizygaeninae remains untested as we sampled only one of the two genera. In the core dataset, we recovered Procridinae as sister to Callizygaeninae + Chalcosiinae. This large clade is the sister lineage to Zygaeninae. The position of Inouelinae could not be resolved. The lineage leading to the extant Zygaenidae appears to have diverged in Late Cretaceous (ca. 86 Ma), while the divergence among the subfamilies occurred several million years before the Cretaceous–Paleogene mass extinction event (ca. 66 Ma). Additionally, we provide a review of known fossil Zygaenidae as Appendix S1. Our results form a strong basis for future studies of zygaenid biosystematics, including their ecology, evolution, and behaviour.

Trends in body mass index in the pre-dolutegravir period in South Africa.

Antiretroviral therapy (ART) is associated with weight gain, but this has been shown to be more marked with dolutegravir and other integrase strand transfer inhibitors. We studied weight gain in people living with HIV (PLWH) on ART compared to the general population in the period before dolutegravir was introduced in a rural South African cohort. Longitudinal analysis of the Ndlovu Cohort Study including 36-48 months' follow-up data. From 2014 to 2019, data were collected annually in Limpopo, rural South Africa. Linear mixed models using HIV status, demographics, ART use and cardiovascular risk factors were used to estimate trends in body mass index (BMI) over time. In total, 1518 adult, non-pregnant participants were included, of whom 518 were PLWH on ART (79.8%), 135 PLWH not yet on ART (20.2%) and 865 HIV-negative. HIV-negative participants had significantly higher BMIs than PLWH on ART at all study visits. There was a significant increase in BMI in all subgroups after 36 months (PLWH on ART, BMI +1.2 kg/m2, P < 0.001; PLWH not on ART, BMI +1.8 kg/m2, P < 0.001 and HIV-negative, BMI +1.3 kg/m2, P < 0.001). The increase in BMI in PLWH and HIV-negative participants is a serious warning signal as obesity results in morbidity and mortality.

The associations of psychosocial work exposures with suicidal ideation in the national French SUMER study

BackgroundThe literature remains scarce on the work-related risk factors for suicide and suicidal ideation. The objectives were to explore the associations of psychosocial work exposures with suicidal ideation in a nationally representative sample of the working population. MethodsThe study was based on the sample of 25,977 employees (14,682 men and 11,295 women) of the national French 2016–17 SUMER survey. The outcome was suicidal ideation assessed using the PHQ-9 instrument. Psychosocial work exposures included various factors from the job strain and effort-reward imbalance models, and other concepts. Statistical analyses were performed using weighted methods, including weighted logistic regression models. Other occupational exposures and covariates were considered. Gender differences were tested. ResultsThe prevalence of suicidal ideation was 3.5 % without any difference between genders. Psychosocial work exposures were found to be associated with suicidal ideation. The strongest association was observed between workplace bullying and suicidal ideation. Associations were also found between job strain model factors, job insecurity, low esteem, work-family conflict, ethical conflict, teleworking, and low meaning, and suicidal ideation. The associations were in general similar for men and women. LimitationsThe study had a cross-sectional design and no causal interpretation could be done. A reporting bias and a healthy worker effect may be suspected. ConclusionPsychosocial work exposures played a major role in suicidal ideation. More research may be needed to confirm our results, as suicidal ideation is an important warning signal for suicide prevention. More primary prevention towards the psychosocial work environment may be useful to reduce suicidal ideation at the workplace.

Early warning signals observed in motor activity preceding mood state change in bipolar disorder.

Alterations in motor activity are well-established symptoms of bipolar disorder, and time series of motor activity can be considered complex dynamical systems. In such systems, early warning signals (EWS) occur in a critical transition period preceding a sudden shift (tipping point) in the system. EWS are statistical observations occurring due to a system's declining ability to maintain homeostasis when approaching a tipping point. The aim was to identify critical transition periods preceding bipolar mood state changes. Participants with a validated bipolar diagnosis were included to a one-year follow-up study, with repeated assessments of the participants' mood. Motor activity was recorded continuously by a wrist-worn actigraph. Participants assessed to have relapsed during follow-up were analyzed. Recognized EWS features were extracted from the motor activity data and analyzed by an unsupervised change point detection algorithm, capable of processing multi-dimensional data and developed to identify when the statistical property of a time series changes. Of 49 participants, four depressive and four hypomanic/manic relapses among six individuals occurred, recording actigraphy for 23.8 ± 0.2 h/day, for 39.8 ± 4.6 days. The algorithm detected change points in the time series and identified critical transition periods spanning 13.5 ± 7.2 days. For depressions 11.4 ± 1.8, and hypomania/mania 15.6 ± 10.2 days. The change point detection algorithm seems capable of recognizing impending mood episodes in continuous flowing data streams. Hence, we present an innovative method for forecasting approaching relapses to improve the clinical management of bipolar disorder.

Forecasting Financial Crisis using Topological Data Analysis Approach

Traditional financial forecasting methods often struggle to capture the complex interactions and emerging patterns that precede financial crises. By leveraging on TDA, this research aims to uncover potential topological features that might serve as early warning signals for impending financial crises. The study adopts the utilization of Topological Data Analysis, an initiative mathematical framework to explore and analyze the inherent topological structures within financial data set, using secondary data from ”Yahoo Finance API”. The results of the analysis conducted using Python indicate that persistence homology in TDA successfully identifies key topology features associated with financial crises, implying its potential for developing early warning systems in the financial sector. The insights gained from this analysis could significantly enhance the early detection and proactive management of system risks in financial market, thereby contributing to more robust risk assessment and policy formulation strategies.

High-resolution and real-time wastewater viral surveillance by Nanopore sequencing

Wastewater genomic sequencing stands as a pivotal complementary tool for viral surveillance in populations. While long-read Nanopore sequencing is a promising platform to provide real-time genomic data, concerns over the sequencing accuracy of the earlier Nanopore versions have somewhat restrained its widespread application in wastewater analysis. Here, we evaluate the latest improved version of Nanopore sequencing (R10.4.1), using SARS-CoV-2 as the model infectious virus, to demonstrate its effectiveness in wastewater viral monitoring. By comparing amplicon lengths of 400 bp and 1200 bp, we revealed that shorter PCR amplification is more suitable for wastewater samples due to viral genome fragmentation. Utilizing mock wastewater samples, we validated the reliability of Nanopore sequencing for variant identification by comparing it with Illumina sequencing results. The strength of Nanopore sequencing in generating real-time genomic data for providing early warning signals was also showcased, indicating that as little as 0.001 Gb of data can provide accurate results for variant prevalence. Our evaluation also identified optimal alteration frequency cutoffs (>50 %) for precise mutation profiling, achieving >99 % precision in detecting single nucleotide variants (SNVs) and insertions/deletions (indels). Monitoring two major wastewater treatment plants in Hong Kong from September 2022 to April 2023, covering over 4.5 million population, we observed a transition in dominant variants from BA.5 to XBB lineages, with XBB.1.5 being the most prevalent variants. Mutation detection also highlighted the potential of wastewater Nanopore sequencing in uncovering novel mutations and revealed links between signature mutations and specific variants. This study not only reveals the environmental implications of Nanopore sequencing in SARS-CoV-2 surveillance but also underscores its potential in broader applications including environmental health monitoring of other epidemic viruses, which could significantly enhance the field of wastewater-based epidemiology.