scholarly journals EXTREME METEO-OCEANIC EVENTS

2018 ◽  
pp. 42 ◽  
Author(s):  
Franck Mazas ◽  
Luc Hamm
Keyword(s):  
Return Period ◽  
Multivariate Analyses ◽  
Extreme Event ◽  
Time Step ◽  
Environmental Extremes ◽  
Comprehensive Framework ◽  
Event Based ◽  
Event Definition ◽  
Univariate Analyses

The two-step framework for over-threshold modelling of environmental extremes proposed in Bernardara et al. (2014) for univariate analyses is generalized to an event-based framework applicable to multivariate analyses. The distinction between sequential values (temporal observations at a given time step) and the event-describing values (such as storm peaks in univariate POT extrapolations) is further detailed and justified. The classification of multivariate analyses introduced in Mazas and Hamm (2017) is refined and linked to the meaning of the concepts of event, sampling and return period that is thoroughly examined; their entanglement being highlighted. In particular, sampling is shown to be equivalent to event definition, identification and description. Event and return period definition are also discussed with respect to the source phenomena or to response (or structure) phenomena. The extreme event approach is thus proposed as a comprehensive framework for univariate and multivariate analyses for assessing natural hazards, seemingly applicable to any field of environmental studies.

scholarly journals Relevance of comorbidities and antithrombotic medication as risk factors for reoperation in patients with chronic subdural hematoma

2021 ◽  
Author(s):  
Alexander Younsi ◽  
Lennart Riemann ◽  
Cleo Habel ◽  
Jessica Fischer ◽  
Christopher Beynon ◽  
...  
Keyword(s):  
Clinical Outcome ◽  
Multivariate Analyses ◽  
Independent Predictor ◽  
Perioperative Complications ◽  
Chronic Subdural Hematoma ◽  
Western Society ◽  
Increased Risk ◽  
Surgical Evacuation ◽  
Antithrombotic Medication ◽  
Univariate Analyses

AbstractIn an aging Western society, the incidence of chronic subdural hematomas (cSDH) is continuously increasing. In this study, we reviewed our clinical management of cSDH patients and identified predictive factors for the need of reoperation due to residual or recurrent hematomas with a focus on the use of antithrombotic drugs. In total, 623 patients who were treated for cSDH with surgical evacuation between 2006 and 2016 at our department were retrospectively analyzed. Clinical and radiological characteristics and laboratory parameters were investigated as possible predictors of reoperation with univariate and multivariate analyses. Additionally, clinical outcome measures were compared between patients on anticoagulants, on antiplatelets, and without antithrombotic medication. In univariate analyses, patients on anticoagulants and antiplatelets presented significantly more often with comorbidities, were significantly older, and their risk for perioperative complications was significantly increased. Nevertheless, their clinical outcome was comparable to that of patients without antithrombotics. In multivariate analysis, only the presence of comorbidities, but not antithrombotics, was an independent predictor for the need for reoperations. Patients on antithrombotics do not seem to necessarily have a significantly increased risk for residual hematomas or rebleeding requiring reoperation after cSDH evacuation. More precisely, the presence of predisposing comorbidities might be a key independent risk factor for reoperation. Importantly, the clinical outcomes after surgical evacuation of cSDH are comparable between patients on anticoagulants, antiplatelets, and without antithrombotics.

scholarly journals Prevalence of Epiretinal Membrane among Subjects in a Health Examination Program in Japan

Life ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 93
Author(s):  
Hiroshi Shimizu ◽  
Ryo Asaoka ◽  
Takashi Omoto ◽  
Yuri Fujino ◽  
Shingo Mitaki ◽  
...  
Keyword(s):  
Epiretinal Membrane ◽  
Multivariate Analyses ◽  
Multiple Logistic Regression Analysis ◽  
Body Height ◽  
Older Age ◽  
Health Examination ◽  
Multiple Logistic Regression ◽  
Older Subjects ◽  
Fundus Photographs ◽  
Univariate Analyses

The prevalence of an epiretinal membrane (ERM) was elucidated using a dataset from a health examination program database in Japan. From the cohort database, 5042 eyes of 2552 subjects were included. The presence of an ERM, cellophane macular reflex (CMR), or preretinal macular fibrosis (PMF) was detected using color fundus photographs, and crude and age-standardized prevalence were obtained. To further assess the possible risk factors of ERM, background parameters were compared between ERM+ and − groups, and multiple logistic regression analysis was performed. ERM was detected in fundus photographs of 275 eyes (eye-based prevalence of 5.5%) from 217 subjects (subject-based prevalence of 8.5%). CMR was detected in 169 eyes (3.4%) of 138 subjects (5.4%), and PMF was detected in 106 eyes (2.1%) of 97 subjects (3.8%). By univariate analyses, compared with ERM− eyes or subjects, higher Scheie’s H grade (p < 0.0001), S grade (p < 0.0001), and glaucoma prevalence (p = 0.0440) were found in ERM+ eyes, and older age (p < 0.0001), more frequent histories of hypertension (p = 0.0033) and hyperlipidemia (p = 0.0441), and more frequent uses of medication for hypertension (p = 0.0034) and hyperlipidemia (p = 0.0074), shorter body height (p = 0.0122), and higher systolic blood pressure (p = 0.0078), and thicker intimal medial thickness (p = 0.0318) were found in ERM+ subjects. By multivariate analyses, older age (p < 0.0001, estimate = 0.05/year) was the only significant factor of ERM prevalence. Age-standardized prevalence of ERM was calculated to be 2.4%, 6.7%, and 13.3% for all ages, subjects older than 40 years, and subjects older than 65 years, respectively. We reported the prevalence of ERM and its subclasses in Japanese subjects. Since its prevalence is remarkably high in older subjects, an ERM can be seen as an important cause of visual impairment in Japan and in areas of the world where individuals live to an advanced age.

scholarly journals Studies on aroma of coffee. Part VIII. Classification of various trade varieties of coffee by coupling of sensory data and multivariate analyses.

1987 ◽  
Vol 51 (7) ◽  
pp. 1745-1752 ◽  
Author(s):  
Kouji WADA ◽  
Seiichi OHGAMA ◽  
Hitoshi SASAKI ◽  
Mitsuya SHIMODA ◽  
Yutaka OSAJIMA
Keyword(s):  
Multivariate Analyses ◽  
Sensory Data

Reports on categorization and classification of human rights violations in Chile (1974–1978)

2018 ◽  
Vol 30 (1) ◽  
pp. 44-63 ◽  
Author(s):  
Marcela Ruiz ◽  
Oriana Bernasconi
Keyword(s):  
Human Rights ◽  
Political Violence ◽  
Social Recognition ◽  
Governmental Organizations ◽  
Non Governmental Organizations ◽  
Legal Perspective ◽  
Communicative Process ◽  
Event Based ◽  
The Relationship

This study analyzes socio-discursive categories used to define and classify the political violence exerted in Chilean human rights reports (1974–1978) to understand the emergence of the repertoire of repression and the construction of victimhood as a social recognition and communicative process in Latin America during the 1970s. These reports are addressed as a professional discursive genre produced by non-governmental organizations whose purpose is to denounce the violation of human rights in the context of political controversies as well as in the Chilean totalitarian context. The discursive genre is characterized by objectivity, the credibility of the information, the event-based approach, the use of statistics to establish the type and magnitude of the violation of human rights. The corpus analyzed consists of 44 reports belonging to human rights archives. The statistical section and comments were coded according to narrative categories (participants, action, cause, time and space). The results show the predominance of the legal perspective to classify the violation of human rights, the emergence of the category of enforced disappearance, the relationship with the socio-political context and the categories elaborated to identify patterns of violation of human rights.

scholarly journals New Updated Classification of Shallow Earthquakes Based on Faulting Style

2020 ◽  
pp. 103-111
Author(s):  
Emad Abulrahman Mohammed Salih Al-Heety
Keyword(s):  
Return Period ◽  
Moment Tensor ◽  
Focal Depth ◽  
Strike Slip ◽  
Shallow Depth ◽  
Main Trend ◽  
Maximum Magnitude ◽  
Centroid Moment Tensor ◽  
Significant Information

Earthquakes occur on faults and create new faults. They also occur on  normal, reverse and strike-slip faults. The aim of this work is to suggest a new unified classification of Shallow depth earthquakes based on the faulting styles, and to characterize each class. The characterization criteria include the maximum magnitude, focal depth, b-constant value, return period and relations between magnitude, focal depth and dip of fault plane. Global Centroid Moment Tensor (GCMT) catalog is the source of the used data. This catalog covers the period from Jan.1976 to Dec. 2017. We selected only the shallow (depth less than 70kms) pure, normal, strike-slip and reverse earthquakes (magnitude ≥ 5) and excluded the oblique earthquakes. The majority of normal and strike-slip earthquakes occurred in the upper crust, while the reverse earthquakes occurred throughout the thickness of the crust. The main trend for the derived b-values for the three classes was: b normal fault>bstrike-slip fault>breverse fault.  The mean return period for the normal earthquake was longer than that of the strike-slip earthquakes, while the reverse earthquakes had the shortest period. The obtained results report the relationship between the magnitude and focal depth of the normal earthquakes. A negative significant correlation between the magnitude and dip class for the normal and reverse earthquakes is reported. Negative and positive correlation relations between the focal depth and dip class were recorded for normal and reverse earthquakes, respectively. The suggested classification of earthquakes provides significant information to understand seismicity, seismtectonics, and seismic hazard analysis.

scholarly journals Hydro-meteorological characteristics and occurrence probability of extreme flood events in Moroccan High Atlas

2020 ◽  
Vol 11 (S1) ◽  
pp. 310-321 ◽  
Author(s):  
Mohamed El Mehdi Saidi ◽  
Tarik Saouabe ◽  
Abdelhafid El Alaoui El Fels ◽  
El Mahdi El Khalki ◽  
Abdessamad Hadri
Keyword(s):  
Return Period ◽  
Peak Flow ◽  
Extreme Event ◽  
Rare Event ◽  
Flood Frequency ◽  
Flood Frequency Analysis ◽  
High Atlas ◽  
Flood Water ◽  
Extreme Flood ◽  
Water Volumes

Abstract Flood frequency analysis could be a tool to help decision-makers to size hydraulic structures. To this end, this article aims to compare two analysis methods to see how rare an extreme hydrometeorological event is, and what could be its return period. This event caused many deadly floods in southwestern Morocco. It was the result of unusual atmospheric conditions, characterized by a very low atmospheric pressure off the Moroccan coast and the passage of the jet stream further south. Assessment of frequency and return period of this extreme event is performed in a High Atlas watershed (the Ghdat Wadi) using historical floods. We took into account, on the one hand, flood peak flows and, on the other hand, flood water volumes. Statistically, both parameters are better adjusted respectively to Gamma and Log Normal distributions. However, the peak flow approach underestimates the return period of long-duration hydrographs that do not have a high peak flow, like the 2014 event. The latter is indeed better evaluated, as a rare event, by taking into account the flood water volumes. Therefore, this parameter should not be omitted in the calculation of flood probabilities for watershed management and the sizing of flood protection infrastructure.

scholarly journals Event-based probabilistic risk assessment of livestock snow disasters in the Qinghai–Tibetan Plateau

2019 ◽  
Vol 19 (3) ◽  
pp. 697-713
Author(s):  
Tao Ye ◽  
Weihang Liu ◽  
Jidong Wu ◽  
Yijia Li ◽  
Peijun Shi ◽  
...  
Keyword(s):  
Climate Change ◽  
Risk Assessment ◽  
High Risk ◽  
Tibetan Plateau ◽  
Return Period ◽  
Probabilistic Risk Assessment ◽  
Future Climate Change ◽  
Tibet Autonomous Region ◽  
Event Based ◽  
Probabilistic Risk

Abstract. Understanding risk using quantitative risk assessment offers critical information for risk-informed reduction actions, investing in building resilience, and planning for adaptation. This study develops an event-based probabilistic risk assessment (PRA) model for livestock snow disasters in the Qinghai–Tibetan Plateau (QTP) region and derives risk assessment results based on historical climate conditions (1980–2015) and present-day prevention capacity. In the model, a hazard module was developed to identify and simulate individual snow disaster events based on boosted regression trees. By combining a fitted quantitative vulnerability function and exposure derived from vegetation type and grassland carrying capacity, we estimated risk metrics based on livestock mortality and mortality rate. In our results, high-risk regions include the Nyainqêntanglha Range, Tanggula Range, Bayankhar Mountains and the region between the Kailas Range and the neighbouring Himalayas. In these regions, annual livestock mortality rates were estimated as >2 % and mortality was estimated as >2 sheep unit km−1 at a return period of 20 years. Prefectures identified with extremely high risk include Guoluo in Qinghai Province and Naqu, and Shigatse in the Tibet Autonomous Region. In these prefectures, a snow disaster event with a return period of 20 years or higher can easily claim total losses of more than 500 000 sheep units. Our event-based PRA results provide a quantitative reference for preparedness and insurance solutions in reducing mortality risk. The methodology developed here can be further adapted to future climate change risk analyses and provide important information for planning climate change adaption in the QTP region.

Generalized Models for the Classification of Abnormal Movements in Daily Life and its Applicability to Epilepsy Convulsion Recognition

2016 ◽  
Vol 26 (06) ◽  
pp. 1650037 ◽  
Author(s):  
José R. Villar ◽  
Paula Vergara ◽  
Manuel Menéndez ◽  
Enrique de la Cal ◽  
Víctor M. González ◽  
...  
Keyword(s):  
Fuzzy Systems ◽  
Classification Error ◽  
Support Vector ◽  
False Alarms ◽  
Abnormal Movements ◽  
Vector Machines ◽  
Clonic Convulsions ◽  
Event Based ◽  
Validation Scheme

The identification and the modeling of epilepsy convulsions during everyday life using wearable devices would enhance patient anamnesis and monitoring. The psychology of the epilepsy patient penalizes the use of user-driven modeling, which means that the probability of identifying convulsions is driven through generalized models. Focusing on clonic convulsions, this pre-clinical study proposes a method for generating a type of model that can evaluate the generalization capabilities. A realistic experimentation with healthy participants is performed, each with a single 3D accelerometer placed on the most affected wrist. Unlike similar studies reported in the literature, this proposal makes use of [Formula: see text] cross-validation scheme, in order to evaluate the generalization capabilities of the models. Event-based error measurements are proposed instead of classification-error measurements, to evaluate the generalization capabilities of the model, and Fuzzy Systems are proposed as the generalization modeling technique. Using this method, the experimentation compares the most common solutions in the literature, such as Support Vector Machines, [Formula: see text]-Nearest Neighbors, Decision Trees and Fuzzy Systems. The event-based error measurement system records the results, penalizing those models that raise false alarms. The results showed the good generalization capabilities of Fuzzy Systems.

Differences in skeletal characters between the disjunct eastern and western populations of ring-billed gulls (Larus delawarensis)

1984 ◽  
Vol 62 (6) ◽  
pp. 1067-1074 ◽  
Author(s):  
Beatrice M. Termaat ◽  
John P. Ryder
Keyword(s):  
Discriminant Function ◽  
Multivariate Analyses ◽  
Correct Identification ◽  
Adult Males ◽  
Lake Of The Woods ◽  
Larus Delawarensis ◽  
Males And Females ◽  
Two Populations ◽  
Univariate Analyses ◽  
Discriminant Function Analyses

Univariate analyses of variance, multivariate analyses of variance (Manova), and discriminant function analyses were performed on measurements of 51 skeletal characters of adult males and females from the disjunct eastern and western populations of the ring-billed gull (Larus delawarensis) in Canada. The analyses established sufficient differences in skeletal characters to permit correct identification of the origin of 34 of 38 males (90%) and 40 of 42 females (95%). The populations are now expanding in range to the extent where new colonies are established in the Lake of the Woods, Ontario region, the historical hiatus between the two populations. Further expansion and contact may well erase the existing skeletal differences of individuals in these populations.

Sign in / Sign up

Export Citation Format

Share Document