Rare Event Research Articles

Analysis of the Bay of Bengal cyclone and its rejuvenation in the Arabian Sea after passing over peninsular India

Tropical Cyclone (TC) Gulab-Shaheen in the Northern Indian Ocean in September 2021 marked an extraordinary and rare climatic event that formed during the monsoon season, making it uncommon. The western North Pacific subtropical High (WNPSH) branch over the northeastern part of India is responsible for the westward movement of the Gulab cyclone in the Bay of Bengal (BoB). The extension of WNPSH and availability of soil moisture influences the cyclone’s movement over the Indian land, and it eventually emerges as a westward-moving cyclone Shaheen in the Arabian Sea (AS). Furthermore, the fourth stage of the Madden-Julian Oscillation propagated over southeast Asia is responsible for aiding cyclogenesis by increasing convective activities and maintaining higher humidity with lower wind shear. Due to this, TC Gulab remains a basic cyclonic flow over the land and moves westward after landfall. In the case of Shaheen, higher tropical cyclone heat potential and SST assisted the remnant of Gulab in rejuvenating over the AS, and lower VWS lets the storm’s center line up vertically, which helps it get more robust. Therefore, this study demonstrates the causes of the cyclone formation in BoB and its rejuvenation in the AS after surviving over the peninsular India.

Necrophagy in cave environments: ecological pressure due to food scarcity? A case study of necrophagy by a harvestman Discocyrtanus canjinjim Carvalho & Kury, 2017 (Arachnida: Opiliones) preying on an Eidmanacris sp. (Orthoptera: Phalangopsidae) carcass

Cave environments present stable abiotic conditions, including permanent darkness, high humidity, and mild temperatures, while biotic factors reflect simplified ecological networks and energy constraints. Cave invertebrates, primarily detritivores and generalists, demonstrate specific adaptations to these conditions. Predation and necrophagy are critical behaviors shaped by the cave's scarcity of food resources. In this study, we report a rare necrophagy event involving Discocyrtanus canjinjim Carvalho & Kury, 2017 (Arachnida: Opiliones) feeding on a deceased cricket (Eidmanacris sp.) (Orthoptera: Phalangopsidae) in the Ponte de Pedra I Cave, Brazil. This limestone cave features large entrances and supports an oligotrophic system. The event occurred in an aphotic zone, where the harvestman displayed no flee behavior despite external stimuli. The presence of other predatory arachnids suggests potential intra-guild competition. Opiliones in the Cerrado and Caatinga exhibit opportunistic carnivory, consuming various prey taxa, including insects and vertebrates. Necrophagy, intra-guild predation, and cannibalism are behaviors reported in subterranean populations due to limited food availability. Climate change and anthropogenic pressures, such as deforestation and mining, threaten the stability of cave environments. Observations like this contribute to understanding the ecological dynamics within caves, highlighting the importance of preserving these fragile ecosystems.

The impact of a weakened AMOC on European heatwaves

Abstract In our changing climate we expect an increase in the frequency of heatwaves, which are extreme events that can have severe consequences for human health, ecosystems, and economies. In this study, we examine how the weakening of the Atlantic Meridional Overturning Circulation (AMOC) may influence the occurrence of extreme warm events in Europe. Our analysis is based on a series of numerical experiments conducted using the EC-Earth3 climate model, which includes three ensembles of 20 Atmospheric Model Intercomparison Project (AMIP)-like members. The large ensemble size makes these simulations well-suited to studying rare extreme events.
Our findings reveal that during boreal summer, the Northern Hemisphere (NH) experiences overall mean cooling, most pronounced in the North Atlantic region. Therefore, the extreme warm events in Europe identified by using a fixed threshold tend to be less frequent. However, the cooling pattern reduces the meridional gradient of near-surface air temperature at high latitudes of the NH. As a result, the speed of the summer jet stream decreases, while the frequency of Ural atmospheric blocking events increases. Atmospheric blocking in summer is closely linked to heatwaves, primarily through subsidence warming and enhanced downward shortwave radiation under clear sky conditions. Consequently, the weakening of the AMOC leads to an increased frequency of heatwaves in Eastern Europe, the only region that presents this opposite trend.
This study highlights the significant role that three-dimensional ocean circulation plays in shaping weather patterns, including extreme events such as heatwaves in Europe. These findings have important implications for future climate projections, as the AMOC is expected to weaken by the end of this century. Thus, as the Earth continues to warm, we may face an increased risk of heatwaves due to the combined effects of global warming and a weakening AMOC.

A NEW LOGARITHMIC TYPE ESTIMATORS FOR ANALYSIS OF NUMBER OF AFTERSHOCKS USING POISSON DISTRIBUTION

Earthquake is a fierce and unavoidable natural disaster. The study of aftershocks following an earthquake provides a comprehensive understanding of seismic activity, making it an important area of research. Although it is important to mention that the use of the Poisson distributed population, to estimate the mass mean of rare events such as earthquakes, has been little studied in the literature. In this context, this study proposes a new class of logarithmic type ratio estimators for estimating the mean of a Poisson distributed population in a simple random sampling without replacement. The proposed estimators are obtained using the logarithmic transformation of the ratio estimator, and the expressions for the mean square error (MSE) are also derived to the first order of approximation. The study demonstrates that the proposed logarithmic type estimators are more efficient than the existing estimators, both theoretically and empirically. The Empirical evidence from a real data study conducted using earthquake data from Turkey confirms the superiority of the proposed estimators over the existing estimators. The study provides valuable insights for researchers and practitioners working with Poisson distributed populations and requiring ratio estimators using simple random sampling without replacement.

ПОТОЧЕЧНЫЕ И КОМПЛЕКСНЫЕ МЕРЫ КАЧЕСТВА В ИССЛЕДОВАНИЯХ АТМОСФЕРЫ И ОКЕАНА: ОБЗОР МЕТОДОВ И ПОДХОДОВ

In the oceanic and atmospheric sciences, various general quantitative indicators, or quality metrics, describe the quality of the various modeling products, including numerical weather prediction, statistical correction, and downscaling. Metrics provide the level of accuracy of model processes reproduction and allow for comparison of models by estimating the uncertainty of their results. This paper presents a classification of the most frequently encountered quality metrics in the scientific literature. Examples are given for each group of quality metrics. In addition to assessing traditional point-by-point metrics, complex metrics that consider various aspects of modeling results are studied. Such specific metrics have an emphasis on the spatial structure, internal correlations, and heterogeneity of the predicted variable fields, ensemble forecasts etc. Special attention in this paper is also devoted to the object-oriented metrics or metrics based for rare and extreme events.

Overview of Clomiphene Citrate Use in Male Hypogonadism and Infertility

Clomiphene Citrate (CC) has been widely used in medicine since the 1970s, primarily as a Selective Estrogen Receptor Modulator (SERM) for female ovulation induction. However, its off-label use in men has gained traction, particularly for the treatment of hypogonadotropic hypogonadism and idiopathic infertility. CC’s mechanism of action, which increases gonadotropin-releasing hormone (GnRH) secretion and subsequently elevates luteinizing hormone (LH) and follicle-stimulating hormone (FSH) levels, offers a unique advantage by preserving the hypothalamic-pituitary-gonadal axis and maintaining fertility. This article presents evidence supporting CC’s efficacy and safety in these contexts, summarizing data from systematic reviews, meta-analyses, and retrospective studies. In hypogonadotropic men, CC has been shown to significantly improve total and free testosterone levels, gonadotropin concentrations, and hypogonadism symptoms, while avoiding common complications of testosterone replacement therapy (TRT), such as secondary polycythemia. CC also demonstrated favorable outcomes in seminal parameters, including sperm concentration and motility, as well as improved pregnancy rates in idiopathic infertility cases. Adverse effects reported with CC use include reduced energy, mood instability, and occasional visual disturbances, most of which are mild and reversible. Long-term safety data are reassuring, with rare severe adverse events such as thrombotic complications. Studies comparing CC to TRT indicate a lower risk of hematological and prostate-related complications, underscoring its safety profile. While the evidence supports CC as a viable alternative or adjunct to TRT in specific patient populations, further research is needed to refine treatment protocols, assess long-term outcomes, and explore biofunctional sperm parameters. Overall, CC represents a promising, cost-effective therapeutic option for addressing male hypogonadism and infertility, with its integration into clinical practice guided by careful patient selection and ongoing monitoring.

Enhanced Sampling with Suboptimal Collective Variables: Reconciling Accuracy and Convergence Speed.

We introduce an enhanced sampling algorithm to obtain converged free energy landscapes of molecular rare events, even when the collective variable (CV) used for biasing is not optimal. Our approach samples a time-dependent target distribution by combining the on-the-fly probability enhanced sampling and its exploratory variant, OPES Explore. This promotes more transitions between the relevant metastable states and accelerates the convergence speed of the free energy estimate. We demonstrate the successful application of this combined algorithm on the two-dimensional Wolfe-Quapp potential, millisecond time-scale ligand-receptor binding in the trypsin-benzamidine complex, and folding-unfolding transitions in chignolin mini-protein. Our proposed algorithm can compute accurate free energies at an affordable computational cost and is robust in terms of the choice of CVs, making it particularly promising for the simulation of complex biomolecular systems.

Statistics of systemwide correlations in the random-field XXZ chain: Importance of rare events in the many-body localized phase

Statistics of systemwide correlations in the random-field XXZ chain: Importance of rare events in the many-body localized phase

Variations in the radiation intensity of the pulsar B0950+08: 9 years of monitoring at a frequency of 110 MHz

The analysis of variations in the radiation intensity of the pulsar B0950+08 from 2014 to 2022 with scales from minutes to years was carried out. The observations were obtained in a round-the-clock daily survey conducted on the Large Phased Array (LPA) radio telescope. The high variability of radiation is shown not only from pulse to pulse, but also at scales greater than 3 min. The average value of the estimated amplitude of these variations in 3.2 minutes is 25 Jy, the modulation index is 1. The average relative amplitude of the interpulse (IP) is 2.00 ± 0.28 % of the main pulse. In individual pulses, the amplitude of the interpulse may exceed the amplitude of the main pulse (MP), but this is a rare event. Radiation is observed in almost the entire period of the pulsar. For the first time, the relative amplitude of radiation between the main pulse and the interpulse (radiation bridge) was measured. When averaging about 10 hours, it varies from 0.8% to 1.31% with an average value of 1.04 ± 0.28 %. A high correlation was found between MP and IP amplitude variations both when averaging profiles over 3.2 minutes and when averaging over years. This correlation is due to refractive interstellar scintillation. The frequency scale of IP diffraction interstellar scintillation was measured for the first time and it was shown that the spectral forms for IP and MP are well correlated and have the same frequency scale. There are strong variations in the frequency scale of scintillation f dif from session to session (time interval from one day) on scales of 200–800 kHz. The refractive scale of scintillation for 1–2 days has been determined. A modulation of radiation with a characteristic scale of about 130 days was detected, which, apparently, is also associated with refractive scintillation.

Platelet spleen tyrosine kinase is a key regulator of anti-PF4 antibody-induced immunothrombosis.

Vaccine-induced immune thrombotic thrombocytopenia (VITT) is a rare but serious prothrombotic adverse event following vaccination with adenovector-based COVID-19 vaccines. Laboratory findings indicate that anti-platelet factor 4 (PF4) immunoglobulin G antibodies are the causing factor for the onset of thromboembolic events in VITT. However, molecular mechanisms of cellular interactions, signaling pathways and involvement of different cell types in VITT antibody-mediated thrombosis are not fully understood. Moreover, uncertainty exists regarding current treatment protocols since the sole anticoagulation was shown to be inefficient to prevent thrombosis progression in severe VITT cases. In this study, we demonstrate that platelet spleen tyrosine kinase (SYK) modulates anti-PF4 VITT-mediated thrombus formation in an ex vivo model of immunothrombosis. Our study showed that the selective inhibition of SYK can abrogate VITT antibody-driven procoagulant platelet formation, activation of plasmatic coagulation as well as platelet-leukocyte interplay. Most importantly, the specific inhibition of SYK in platelets but not in neutrophils prevented VITT antibody-induced multicellular thrombus formation, without perturbing the platelet function. Our findings indicate that the specific targeting of platelet SYK might be a promising therapeutic approach to prevent thrombotic complications in patients with antibody-mediated immunothrombosis.

Operative Fires: Variables Associated with Polymethylmethacrylate Flammability.

Operative fires are rare but unforgettable events, with the potential for devastating outcomes. It is estimated that 650 operating room (OR) fires occur each year in the United States, with the use of electrocautery devices and polymethylmethacrylate (PMMA) as the primary ignition and fuel sources. There are several case reports of OR fires caused by PMMA and electrocautery in the literature, but, to our knowledge, no formal studies have been performed exposing the flammability of PMMA and how PMMA reacts to an electrocautery ignition source. We studied the flammability of PMMA with electrocautery as an ignition source in a controlled laboratory setting. We used 2 different brands of PMMA, both with and without antibiotics. The PMMA was prepared according to the manufacturer's guidelines. In our model, which used a cadaveric leg, the PMMA was placed next to a femoral component that is used in total knee arthroplasty (TKA). Electrocautery was applied at 30-second intervals for a total of 15 minutes. Flammability was defined as any visualized spark or flame while using an electrocautery device. The heat resulting from the chemical reaction was recorded every 30 seconds with a thermal imaging camera (TIC). Video recording was used during the experiment to document the flammability events. A total of 108 tests were performed. PMMA with and without antibiotics proved to be flammable with the use of electrocautery. All flammability occurred within 7 minutes of combining the monomer and the powder. Increased flammability was seen with the use of antibiotic additives. PMMA was found to be highly flammable in the initial curing period when exposed to electrocautery as an ignition source. When PMMA is ready for application, we recommend that an "electrocautery timeout" be performed, wherein the electrocautery device is removed from the operating field for a minimum of 7 minutes or until the PMMA has fully hardened.

Pembrolizumab-induced acquired lipodystrophy: a case report and review of the literature.

Acquired generalized lipodystrophy (AGL) is a rare complication of immune checkpoint inhibitors (ICIs) and is associated with immune-mediated loss of adipose tissue, peripheral resistance to insulin, and serious metabolic complications. Here we report a new case of ICI-induced AGL and provide an updated literature review of published cases. We report a 39-year-old female patient treated with adjuvant pembrolizumab for stage IIIC nevoid melanoma with ICI-induced AGL. After six cycles of pembrolizumab, she developed a 40 lb weight loss with fat wasting, a decreased leptin level, significant liver function abnormalities, hepatic steatosis, hypertriglyceridemia, and subsequently was found to have severe insulin dependence and resistance. No corticosteroids were given and pembrolizumab was discontinued. AGL persists at 3-year follow up and patient remains free of melanoma progression. Literature review identified an additional seven patients who developed ICI-induced acquired lipodystrophy, predominantly female. Of the identified cases, three patients received steroids without resolution of their acquired lipodystrophy, while one patient had resolution without steroid treatment. Five patients and our case were treated with ICIs for melanoma, and all had at least a partial response to treatment. ICI-induced acquired lipodystrophy is an exceedingly rare event with profound clinical consequences. Our case report and literature review better characterized the clinical course and treatment outcomes of these patients. With the increasing utilization of ICIs in treating cancer, further studies to better understand the underlying mechanism and to guide clinical management of the metabolic complications are needed.

Expanding foresight methodology to better understand the unknown future and identify hard-to-predict events

This study focuses on the integration of methods from different theories and research concepts into futures studies in order to better understand the obscure future through the identification of unpredictable and hard-to-predict rare events and factors. Particular emphasis in this study is placed on systems theory, cybernetics, synergetics, theory of chaos, bifurcation theory, catastrophe theory, thermodynamics, and the theory of self-organized criticality that could elucidate the unknown and offer new insights to futures studies. White, black and grey swans, dragon kings, wild cards, and weak signals are rare and high-impact events commonly referred to in the risk management literature, synergetics, and futures studies. The academic literature does not always accurately identify commonalities and differences between them, as well as relevant research tools. This study clarifies the categories of unknown and types of uncertainty associated with these events, their characteristics, and the related existing foresight methods. It is also suggested to enrich foresight methodology by adding instruments from other disciplines.

Anti-Seismic Performance Research of Complicated Nodes Involved in Ultra-Limited Steel Structures Subjected to Rare Occurrence Earthquakes

This study focuses on the seismic performance of complicated nodes in the ultra-limited steel structure under rare occurrence earthquakes. The Xi’an Urban Exhibition Center (Chang’an Cloud) is chosen as the engineering background, and the ANSYS (18.0) analysis software is employed. Based on the overall importance and the extent of post-damage impacts, the critical nodes are selected for structural design. The research aims to develop simplified and reliable structural forms that can withstand the most adverse conditions at both the overall nodes and local component levels. Stress distribution under the most unfavorable scenarios is calculated to achieve the seismic design objectives of the overall structure. The research results indicate that localized stress concentration areas can reach or exceed the yield strength of the steel, which enters the plastic phase. The Von Mises stresses in the remaining nodes are lower than the yield strength of the steel. The overall performance is excellent without significant plastic deformation. Thus, the design requirements for non-yielding performance under rare seismic events are met. The conclusions can provide reliable references for the critical structural techniques and seismic design of complicated nodes.

Double strike without stroke: a postpartum headache with too many causes.

Pregnancy and postpartum are phases in the women's life where the thrombotic risk is increased both on the venous and on the arterial side. We are presenting the case of a young woman at the third pregnancy, carried out without complications until delivery, whose postpartum was characterized by the occurrence of headache. Neuroimaging studies were performed, firstly brain computed tomography (CT) with CT Angiography and after brain Magnetic Resonance Imaging (MRI) with MR Angiography. The main finding was the simultaneous presence of two cerebrovascular vascular diseases, i.e. cerebral venous thrombosis (CVT) and left carotid dissection, without stroke. The neuroimaging features of both the diseases were analyzed and both CVT and dissection had neuroimaging markers of acute timing. After starting heparin therapy at anticoagulant dose the clinical symptoms disappeared within a few days. CVT is a rare event with a peak in the late pregnancy and puerperium, but other arterial cerebrovascular events, as spontaneous dissection, have not an increased incidence in the postpartum. Headache is one of the main symptoms for all these cerebrovascular diseases, but usually stroke is the accompanying event. This is not always true and the presented case illustrates this unexpected occurrence. Headache is a nonspecific and highly prevalent symptom and in the postpartum period it could raise the suspicion of CVT. Sometimes several different causes are found for the same symptom and concurrent acute cerebrovascular diseases might be considered. Neuroimaging investigations may help for diagnosis and timing concurrent thrombotic diseases, particularly DWI-MRI.

Sensitivity of Arctic marine heatwaves to half-a-degree increase in global warming: 10-fold frequency increase and 15-fold extreme intensity likelihood

Abstract We utilize the 50-member MPI-ESM-LR Earth System model to investigate the projected changes in Arctic marine heatwaves' (MHWs) characteristics caused by an additional 0.5°C increase in global warming, from 1.5°C to 2°C, with respect to pre-industrial levels. Our results indicate that this 0.5°C increase in global warming triggers an intensified response in both the Arctic's mean sea surface temperature (SST) and its variability. In a 2°C warmer world, one out of every four summer months would be warmer than the current climate. We detect a nonlinear increase in MHW intensity in a 2°C world, which is characterized by a break in slope occurring around the year 2042 ± 2 (across 50 ensemble members of the SSP5-8.5 scenario). At the estimated post-break dates, the intensity rate roughly doubles, leading to MHWs in a 2°C world with average cumulative heat intensity 100°C*days higher than in a 1.5°C world. Further results reveal that an extremely rare MHW with an intensity of 3.19°C, classified as a 1-in-100-year event in a 1.5°C world, is expected to transform into a 1-in-7-year event in a 2°C world. This transition signifies an approximately 15-fold increase in the likelihood of such events occurring due to a 0.5°C increase in global warming. Likewise, an uncommon event of years with 125 MHW days in a 1.5°C world is projected to become a 1-in-10-year event in a 2°C world, resulting in a 10-fold increase in occurrence probability. The main contributor to these changes is predominantly the rise in mean SST, with enhanced SST variability playing a minor role. These findings highlight that a 2°C world could lead to a substantial escalation of the frequency and intensity of MHWs in the Arctic compared to a 1.5°C world, transforming what are currently rare extreme events into more common events, with significant implications for global climate dynamics and the well-being of Arctic ecosystems and communities.

First Observation of a Nuclear Recoil Peak at O(100eV) with Crab: A Potential New Calibration Standard for Cryogenic Detectors

Any experiment aiming to measure rare events, like Coherent Elastic neutrino-Nucleus Scattering (CEνNS) or hypothetical Dark Matter scattering, via nuclear recoils in cryogenic detectors relies crucially on a precise detector calibration at sub-keV energies. The Crab collaboration developed a new calibration technique based on the capture of thermal neutrons inside the target crystal. Together with the Nucleus experiment, first measurements with a moderated 252Cf neutron source and a cryogenic CaWO4 detector were taken. We observed for the first time the 112eV peak caused by the 182W(n, γ)183W capture reaction and subsequent nuclear recoils. Currently, Crab is preparing a precision measurement campaign based on a monochromatic flux of thermal neutrons from the 250-kW Triga-mark II nuclear reactor at TU Wien. In this contribution, we introduce the Crab technique, present the first measurement of the 112eV peak, report the preparations for the precision measurement campaign, and give an outlook on the impact on the field of cryogenic detectors.

Incorporating Climatic Extremes Using the GEV Distribution Improves SDM Range Edge Performance

ABSTRACTAimThe changing frequency and intensity of climatic extremes due to climate change can have sudden and adverse impacts on the distribution of species. While species distribution modelling is a vital tool in ecological applications, current approaches fail to fully capture the distribution of climatic extremes, particularly of rare events with the most disruptive potential. Especially at the edges of species' ranges, where conditions are already less favourable, predictions might be inaccurate when these extremes are not well represented.LocationEurope.TaxonTree species.MethodsWe present a novel approach to integrate extreme events into species distribution models based on the generalised extreme value (GEV) distribution. This distribution, following from the extreme value theory has been established as a valuable tool in analysing climatic extremes, both in an ecological context and beyond. The approach relying on the GEV distribution is broadly applicable, readily transferable across species and relies on widely available data. We demonstrate the efficacy of our approach for 28 European tree species, illustrating its superior ability to fully capture the distribution of climatic extremes compared to state‐of‐the‐art methods.ResultsWe found that incorporating parameters on climatic extremes derived from the GEV distribution increased model performance (AICmodel) and characterised range edges more accurately (AUCedge) compared to competing approaches. However, general AUC values were only marginally increased across the species and study period analysed. Overall, the GEV model predicted a narrower niche for the species included in this study.Main ConclusionsIncorporating climatic extremes can impact spatial predictions of species distribution models, especially at range margins. We found that using the GEV distribution to characterise extreme variables in SDMs yields the best performance at these distribution edges. Given the importance of range edges for species conservation, a detailed inclusion of extremes in SDMs employed for those applications will help ensure robust conclusions.

Two major sudden stratospheric warmings during winter 2023/2024

Major sudden stratospheric warmings (SSWs) occur in the Arctic around six times per decade. During winter 2023/2024, two major SSWs occurred – a relatively rare event, having occurred on average only once per decade. Here, we summarise the evolution of the two SSWs, their dynamics and impacts on stratospheric chemical processing and tropospheric weather patterns. While both SSWs were displacement events, they evolved remarkably differently. The 16 January SSW was short‐lived and did not exert a canonical influence on surface weather. In contrast, the 4 March SSW followed a more typical evolution, albeit with only weak coupling to the troposphere.

Exploring Sex-Based Differences Among Adolescent Perpetrators of Sexual Violence: A Test of General Strain Theory

Using data from the 2022 Minnesota Student Survey ( N = 85,004), this study applies multivariate logistic analyses for rare events to understand better sexual violence committed by adolescents from a general strain theory perspective. Informed by this theory, measures of unmet goals, loss of positive stimuli, and exposure to negative stimuli were used to develop multivariate logistic models that were examined to improve our empirical understanding of adolescent perpetration of sexual violence. The study also investigates whether sex-based differences exist among perpetrators. Results indicate that older adolescents and males were more likely to perpetrate sexual violence, with various forms of strain increasing the risk of perpetration as well as demonstrating slightly similar effects across sexes.