scholarly journals Aveiro Canyon Head (Portugal) Submarine Slope Instability Assessment

2020 ◽  
Vol 10 (24) ◽  
pp. 9038
Author(s):  
Nuno Lapa ◽  
Fernando M. F. S. Marques ◽  
Aurora Rodrigues
Keyword(s):  
Marine Environment ◽  
Regional Scale ◽  
Slope Angle ◽  
Area Under The Curve ◽  
Roc Curves ◽  
Information Value ◽  
Slope Instability ◽  
Landslide Inventory ◽  
Spatial And Temporal Variability ◽  
Sedimentary Dynamics

Mass wasting events are the main processes of sedimentary dynamics that affect the marine environment and which, due to their spatial and temporal variability, are difficult to study and evaluate. Affecting the marine floor, between the coastline and the abyssal plain, these processes are triggered by multiple causes, having different magnitudes and causing drastic changes and impacts on the marine environment and human activities. In this paper, the submarine landslide susceptibility affecting the upper course of the Aveiro canyon (West Iberian Margin) is addressed using statistical models which are based on the statistical relations between a landslide inventory and the landslide predisposing factors bathymetry, sediment cover, slope angle, aspect and curvature. The statistical methods were the widely proven bivariate information value (IV) and the multivariate logistic regression (LR). The model results were validated against the landslide inventory using receiver operating characteristic (ROC) curves and the corresponding area under the curve (AUC), which provided satisfactory results, with IV AUC = 0.79 and LR AUC = 0.83, in spite of the limitations of the databases used in this study. The results obtained suggest that these methods may be useful for the preliminary assessment of sea floor slope instability at a regional scale of analysis, enabling the selection of sites to be studied with much more detailed and expensive methods.

Communality from equal weight for GIS-based landslide susceptibility mapping

2020 ◽  
Author(s):  
Sandip Som ◽  
Saibal Ghosh ◽  
Soumitra Dasgupta ◽  
Thrideep Kumar ◽  
J. N. Hindayar ◽  
...  
Keyword(s):  
Land Use Planning ◽  
Landslide Susceptibility ◽  
Regional Scale ◽  
Model Development ◽  
Model Performance ◽  
Roc Curves ◽  
Landslide Inventory ◽  
Landslide Susceptibility Mapping ◽  
Equal Weight ◽  
Landslide Susceptibility Index

Abstract Modeling landslide susceptibility is one of the important aspects of land use planning and risk management. Several modeling methods are available based either on highly specialized knowledge on causative attributes or on good landslide inventory data to use as training and testing attribute on model development. Understandably, these two criteria are rarely available for local land regulators. This paper presents a new model methodology, which requires minimum knowledge of causative attributes and does not depend on landslide inventory. As landslide causes due to the combined effect of causative attributes, this model utilizes communality (common variance) of the attributes, extracted by exploratory factor analysis and used for calculation of landslide susceptibility index. The model can understand the inter-relationship of different geo-environmental attributes responsible for landslide along with identification and prioritization of attributes on model performance to delineate non-performing attributes. Finally, the model performance is compared with the well established AHP method (knowledge driven) and FRM method (data driven) by cut-off independent ROC curves along with cost-effectiveness. The model shows it’s performance almost at par with the established models, involving minimum modeling expertise. The findings and results of the present work will be helpful for the town planners and engineers on a regional scale for generalized planning and assessment.

scholarly journals Sea cliff instability susceptibility at regional scale: a statistically based assessment in southern Algarve, Portugal

2013 ◽  
Vol 1 (3) ◽  
pp. 1965-2003 ◽  
Author(s):  
F. M. S. F. Marques ◽  
R. Matildes ◽  
P. Redweik
Keyword(s):  
Natural Hazard ◽  
Regional Scale ◽  
Roc Curves ◽  
Predisposing Factors ◽  
Information Value ◽  
Multivariate Logistic Regression ◽  
Land Use Regulations ◽  
Conditioning Factors ◽  
Different Types ◽  
Sea Cliff

Abstract. Mass movements of different types and sizes are the main processes of sea cliff evolution and also a considerable source of natural hazard, making its assessment a relevant issue in terms of human losses prevention and land use regulations. To address the assessment of the spatial component of sea cliff hazard, i.e. the susceptibility, a statistically based study was made to assess the capacity of a set of conditioning factors to express the occurrence of sea cliff failures affecting areas located along their top. The study was based on the application of the bivariate Information Value and multivariate Logistic regression statistical methods, using a set of predisposing factors for cliff failures, mainly related with geology (lithology, bedding dip, faults) and geomorphology (maximum and mean slope, height, aspect, plan curvature, toe protection) which were correlated with a photogrammetry based inventory of cliff failures occurred in a 60 yr period (1947–2007). The susceptibility models were validated against the inventory data using standard success rate and ROC curves, and provided encouraging results, indicating that the proposed approaches are effective for susceptibility assessment. The results obtained also stress the need for improvement of the predisposing factors to be used in this type of studies and the need of detailed and systematic cliff failures inventories.

scholarly journals Sea cliff instability susceptibility at regional scale: a statistically based assessment in the southern Algarve, Portugal

2013 ◽  
Vol 13 (12) ◽  
pp. 3185-3203 ◽  
Author(s):  
F. M. S. F. Marques ◽  
R. Matildes ◽  
P. Redweik
Keyword(s):  
Natural Hazard ◽  
Regional Scale ◽  
Roc Curves ◽  
Predisposing Factors ◽  
Information Value ◽  
Multivariate Logistic Regression ◽  
Land Use Regulations ◽  
Conditioning Factors ◽  
Different Types ◽  
Sea Cliff

Abstract. Sea cliff evolution is dominated by the occurrence of slope mass movements of different types and sizes, which are a considerable source of natural hazard, making their assessment a relevant issue in terms of human loss prevention and land use regulations. To address the assessment of the spatial component of sea cliff hazards, i.e. the susceptibility, a statistically based study was made to assess the capacity of a set of conditioning factors to express the occurrence of sea cliff failures affecting areas located along their top. The study was based on the application of the bivariate information value and multivariate logistic regression statistical methods, using a set of predisposing factors for cliff failures, mainly related to geology (lithology, bedding dip, faults) and geomorphology (maximum and mean slope, height, aspect, plan curvature, toe protection), which were correlated with a photogrammetry-based inventory of cliff failures that occurred in a 60 yr period (1947–2007). The susceptibility models were validated against the inventory data using standard success rate and ROC curves, and provided encouraging results, indicating that the proposed approaches are effective for susceptibility assessment. The results obtained also stress the need for improvement of the predisposing factors to be used in this type of study and the need for detailed and systematic cliff failure inventories.

Is Overgrazing Really Influencing Soil Erosion?

Water ◽  
2018 ◽  
Vol 10 (8) ◽  
pp. 1077 ◽  
Author(s):  
Ionut Nicu
Keyword(s):  
Soil Erosion ◽  
Success Rate ◽  
Slope Angle ◽  
Area Under The Curve ◽  
Temporal Analysis ◽  
Drainage Density ◽  
Information Value ◽  
Topographic Wetness Index ◽  
Conditioning Factors ◽  
Multi Temporal

Soil erosion is a serious problem spread over a variety of climatic areas around the world. The main purpose of this paper is to produce gully erosion susceptibility maps using different statistical models, such as frequency ratio (FR) and information value (IV), in a catchment from the northeastern part of Romania, covering a surface of 550 km2. In order to do so, a total number of 677 gullies were identified and randomly divided into training (80%) and validation (20%) datasets. In total, 10 conditioning factors were used to assess the gully susceptibility index (GSI); namely, elevation, precipitations, slope angle, curvature, lithology, drainage density, topographic wetness index, landforms, aspect, and distance from rivers. As a novelty, overgrazing was added as a conditioning factor. The final GSI maps were classified into four susceptibility classes: low, medium, high, and very high. In order to evaluate the two models prediction rate, the AUC (area under the curve) method was used. It has been observed that adding overgrazing as a contributing factor in calculating GSI does not considerably change the final output. Better predictability (0.87) and success rate (0.89) curves were obtained with the IV method, which proved to be more robust, unlike FR method, with 0.79 value for both predictability and success rate curves. When using sheepfolds, the value decreases by 0.01 in the case of the FR method, and by 0.02 in the case of the success rate curve for the IV method. However, this does not prove the fact that overgrazing is not influencing or accelerating soil erosion. A multi-temporal analysis of soil erosion is needed; this represents a future working hypothesis.

Evaluation of the clot burden score (cbs) for acute ischemic stroke (ais) in intent-to-treat patients.

2019 ◽  
Vol 1 (1) ◽  
pp. 11-15 ◽  
Author(s):  
Sarah Yaziz ◽  
Ahmad Sobri Muda ◽  
Wan Asyraf Wan Zaidi ◽  
Nik Azuan Nik Ismail
Keyword(s):  
Ischemic Stroke ◽  
Clinical Outcome ◽  
Acute Ischemic Stroke ◽  
Predictive Value ◽  
Area Under The Curve ◽  
Rank Correlation ◽  
Treatment Decision ◽  
Roc Curves ◽  
Significant Negative Correlation ◽  
Clot Burden

Background : The clot burden score (CBS) is a scoring system used in acute ischemic stroke (AIS) to predict patient outcome and guide treatment decision. However, CBS is not routinely practiced in many institutions. This study aimed to investigate the feasibility of CBS as a relevant predictor of good clinical outcome in AIS cases. Methods:  A retrospective data collection and review of AIS patients in a teaching hospital was done from June 2010 until June 2015. Patients were selected following the inclusion and exclusion criteria. These patients were followed up after 90 days of discharge. The Modified Rankin scale (mRS) was used to assess their outcome (functional status). Linear regression Spearman Rank correlation was performed between the CBS and mRS. The quality performance of the correlations was evaluated using Receiver operating characteristic (ROC) curves. Results: A total of 89 patients with AIS were analysed, 67.4% (n=60) male and 32.6% (n=29) female. Twenty-nine (29) patients (33.7%) had a CBS ?6, 6 patients (6.7%) had CBS <6, while 53 patients (59.6%) were deemed clot free. Ninety (90) days post insult, clinical assessment showed that 57 (67.6%) patients were functionally independent, 27 (30.3%) patients functionally dependent, and 5 (5.6%) patients were deceased. Data analysis reported a significant negative correlation (r= -0.611, p<0.001). ROC curves analysis showed an area under the curve of 0.81 at the cut-off point of 6.5. This showed that a CBS of more than 6 predicted a good mRS clinical outcome in AIS patients; with sensitivity of 98.2%, specificity of 53.1%, positive predictive value (PPV) of 76%, and negative predictive value (NPV) of 21%. Conclusion: CBS is a useful additional variable for the management of AIS cases, and should be incorporated into the routine radiological reporting for acute ischemic stroke (AIS) cases.

scholarly journals Magnetic resonance cisternography imaging findings related to the leakage of Gadolinium into the subarachnoid space

2021 ◽  
Author(s):  
Rei Nakamichi ◽  
Toshiaki Taoka ◽  
Hisashi Kawai ◽  
Tadao Yoshida ◽  
Michihiko Sone ◽  
...  
Keyword(s):  
Magnetic Resonance ◽  
Subarachnoid Space ◽  
Area Under The Curve ◽  
Rank Correlation ◽  
Predictive Performance ◽  
Roc Curves ◽  
Imaging Findings ◽  
Spearman’S Rank Correlation ◽  
Sagittal Sinus ◽  
Magnetic Resonance Cisternography

Abstract Purpose To identify magnetic resonance cisternography (MRC) imaging findings related to Gadolinium-based contrast agent (GBCA) leakage into the subarachnoid space. Materials and methods The number of voxels of GBCA leakage (V-leak) on 3D-real inversion recovery images was measured in 56 patients scanned 4 h post-intravenous GBCA injection. Bridging veins (BVs) were identified on MRC. The numbers of BVs with surrounding cystic structures (BV-cyst), with arachnoid granulations protruding into the superior sagittal sinus (BV-AG-SSS) and the skull (BV-AG-skull), and including any of these factors (BV-incl) were recorded. Correlations between these variables and V-leak were examined based on the Spearman’s rank correlation coefficient. Receiver-operating characteristic (ROC) curves were generated to investigate the predictive performance of GBCA leakage. Results V-leak and the number of BV-incl were strongly correlated (r = 0.609, p < 0.0001). The numbers of BV-cyst and BV-AG-skull had weaker correlations with V-leak (r = 0.364, p = 0.006; r = 0.311, p = 0.020, respectively). The number of BV-AG-SSS was not correlated with V-leak. The ROC curve for contrast leakage exceeding 1000 voxels and the number of BV-incl had moderate accuracy, with an area under the curve of 0.871. Conclusion The number of BV-incl may be a predictor of GBCA leakage and a biomarker for waste drainage function without using GBCA.

Factors affecting progression to permanent atrial fibrillation in an unselected population of patients with non-permanent form of atrial fibrillation

2020 ◽  
Vol 41 (Supplement_2) ◽  
Author(s):  
V.L Malavasi ◽  
E Fantecchi ◽  
V Tordoni ◽  
L Melara ◽  
A Barbieri ◽  
...  
Keyword(s):  
Atrial Fibrillation ◽  
Cox Regression ◽  
Area Under The Curve ◽  
Roc Curves ◽  
Factors Affecting ◽  
Cox Proportional Hazard ◽  
Significant Difference ◽  
History Of ◽  
Unselected Population ◽  
Cox Proportional Hazard Regression

Abstract Background Natural history of atrial fibrillation (AF) shows a progression of arrhythmia from non-permanent to permanent AF. Permanent AF was found associated with a worse prognosis than non-permanent one. Aim To assess the factors associated with progression to permanent AF in an unselected population of AF patients with non-permanent AF. Methods In this prospective study we enrolled in- as well as out-patients with non-permanent AF and age ≥18 years, with at least one episode of ECG-documented AF within 1 year. The patients were followed-up at 1 month and every 6 months thereafter. Results Out of 523 patients, 314 (60%) were in non-permanent AF (80 [25.5%] paroxysmal AF, 165 [52.5%] persistent AF, 69 [2%] first diagnosed AF), mostly male (188, 59.9%), median age 71 years (IQ range 62–77), median CHA2DS2VASc 3 (1–4), median HATCH score 1 (1–2). After a median follow-up of 701 (IQ range 437–902) days, 66 patients (21%) showed permanent AF. CHA2DS2VASc and HATCH scores were incrementally associated to progression to permanent AF (CHA2DS2VASc χ2 p=0.001; HATCH χ2 p=0.017; p for trend CHA2DS2VASc &lt;0.001, HATCH p=0.001). At multivariable Cox proportional hazard regression the following variables were significantly associated with AF progression: age (hazard ratio [HR] 1.041; 95% CI: 1.004–1.079; p=0.028), at least moderate left atrial (LA) enlargement (&gt;42 ml/m2) (HR 2.092; 95% CI: 1.132–3.866; p=0.018), antiarrhythmics drugs after the enrollment (HR 0.087; 95% CI: 0.011–0.662; p=0.018), EHRA score &gt;2 (HR 0.351; 95% CI: 0.158–0.779; p=0.010) and Valvular HD (HR 2.161; 95% CI: 1.057–4.420; p=0.035). Adding LA dilation to HATCH score (HATCH-LA) and assigning 2 points based on multivariable Cox regression, HATCH-LA was statistically better in ROC curves in prediction of AF progression vs HATCH score (area under the curve 0.695 vs 0.636; DeLong p=0.0225). Survival-free curves on freedom from permanent AF using as discriminator HATCH-LA score ≤2 vs &gt;2 led to a statistically significant difference (χ2=16.080 p&lt;0.001), but the same was not found for HATCH score (χ2 =3.099; p=0.078). Conclusions In patients without permanent AF, progression of AF was independentely related to age, LA dilation, AF symptoms severity, antiarrhythmic drugs and Valvular HD. HATCH score predicted AF progression and adding to it LA dilation (at least moderate) improved patients stratification for the risk of evolution to permanent AF. Funding Acknowledgement Type of funding source: None

Gestational Age Dependency of Umbilical Cord Serum IL-6 Levels for Detecting Fetal Inflammation

2020 ◽  
Author(s):  
Sota Iwatani ◽  
Takao Kobayashi ◽  
Sachiko Matsui ◽  
Akihiro Hirata ◽  
Miwa Yamamoto ◽  
...  
Keyword(s):  
Umbilical Cord ◽  
Gestational Age ◽  
Area Under The Curve ◽  
Roc Curves ◽  
Significant Negative Correlation ◽  
Cord Serum ◽  
Very Preterm ◽  
Key Points ◽  
Extremely Preterm ◽  
Preterm Newborns

Objective The fetal inflammatory response syndrome (FIRS) is characterized by elevated concentrations of inflammatory cytokines in fetal blood, with preterm delivery and morbidity. Umbilical cord serum interleukin-6 (UC-s-IL-6) is an ideal marker for detecting FIRS. However, the effect of gestational age (GA) on UC-s-IL-6 levels has not been reported. This study aimed to determine the relationship between GA and UC-s-IL-6 levels, and GA-dependent cutoff values of UC-s-IL-6 levels for detecting fetal inflammation. Study Design UC-s-IL-6 concentrations were measured in 194 newborns (44 extremely preterm newborns (EPNs) at 22–27 weeks' GA, 68 very preterm newborns (VPNs) at 28–31 weeks' GA, and 82 preterm newborns (PNs) at 32–34 weeks' GA). Linear regression analyses were used to correlate GA and UC-s-IL-6 levels. Receiver operating characteristic (ROC) curves analyses were performed for detecting the presence of funisitis, as the histopathological counterpart of FIRS. Results A significant negative correlation between GA and UC-s-IL-6 levels was found in newborns with severe funisitis (r s =  − 0.427, p = 0.004) and those with mild funisitis (r s =  − 0.396, p = 0.025). ROC curve analyses revealed the area under the curve for detecting funisitis were 0.856, 0.837, and 0.622 in EPNs, VPNs, and PNs, respectively. The UC-s-IL-6 cutoff value in EPNs (28.1 pg/mL) exceeded those in VPNs and PNs (3.7 and 3.0 pg/mL, respectively). Conclusion UC-s-IL-6 levels were inversely correlated with GA especially in newborns with funisitis. Such GA dependency of UC-s-IL-6 should be considered for detecting fetal inflammation. Key Points

scholarly journals A novel predictor of clinical progression in patients on active surveillance for prostate cancer

2019 ◽  
Vol 13 (8) ◽  
Author(s):  
Guan Hee Tan ◽  
Antonio Finelli ◽  
Ardalan Ahmad ◽  
Marian Wettstein ◽  
Alexandre Zlotta ◽  
...  
Keyword(s):  
Prostate Cancer ◽  
Active Surveillance ◽  
Cox Regression ◽  
Area Under The Curve ◽  
Progression Free Survival ◽  
Roc Curves ◽  
Standard Of Care ◽  
Low Risk ◽  
Clinical Progression

Introduction: Active surveillance (AS) is standard of care in low-risk prostate cancer (PC). This study describes a novel total cancer location (TCLo) density metric and aims to determine its performance in predicting clinical progression (CP) and grade progression (GP).     Methods: This was a retrospective study of patients on AS after confirmatory biopsy (CBx). We excluded patients with Gleason ≥7 at CBx and <2 years follow-up. TCLo was the number of locations with positive cores at diagnosis (DBx) and CBx. TCLo density was TCLo / prostate volume (PV). CP was progression to any active treatment while GP occurred if Gleason ≥7 was identified on repeat biopsy or surgical pathology. Independent predictors of time to CP or GP were estimated with Cox regression. Kaplan-Meier analysis compared progression-free survival curves between TCLo density groups. Test characteristics of TCLo were explored with receiver operating characteristic (ROC) curves.     Results: We included 181 patients who had CBx between 2012-2015, and met inclusion criteria. The mean age of patients was 62.58 years (SD=7.13) and median follow-up was 60.9 months (IQR=23.4). A high TCLo density score (>0.05) was independently associated with time to CP (HR 4.70, 95% CI: 2.62-8.42, p<0.001), and GP (HR 3.85, 95% CI: 1.91-7.73, p<0.001). ROC curves showed TCLo density has greater area under the curve than number of positive cores at CBx in predicting progression.     Conclusion: TCLo density is able to stratify patients on AS for risk of CP and GP. With further validation, it could be added to the decision-making algorithm in AS for low-risk localized PC.

ESR and CRP Diagnostic Thresholds for Prosthetic Joint Infection in Hip Hemiarthroplasty

2020 ◽  
Vol 4 (04) ◽  
pp. 187-192
Author(s):  
Jared A. Warren ◽  
Oliver Scotting ◽  
Hiba K. Anis ◽  
James Bircher ◽  
Alison K. Klika ◽  
...  
Keyword(s):  
Prosthetic Joint Infection ◽  
Joint Infection ◽  
Area Under The Curve ◽  
Roc Curves ◽  
Musculoskeletal Infection ◽  
Hip Hemiarthroplasty ◽  
Diagnostic Thresholds ◽  
Diagnostic Threshold ◽  
Prosthetic Joint ◽  
The Mean

AbstractDiagnostic thresholds used to standardize the definition for prosthetic joint infection (PJI) have largely focused on total joint arthroplasty (TJA). Established PJI thresholds exist for serum erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) in TJA; however, they do not exist for revision hip hemiarthroplasty (rHHA). The purpose of this study was to establish thresholds for (1) ESR and (2) CRP to diagnose PJI in rHHA. Data were collected on a prospective cohort of 69 rHHA patients undergoing orthopaedic surgery between 1/2017 and 2/2019 in a single health care system. Procedures were categorized as septic or aseptic revisions using Musculoskeletal Infection Society (MSIS) criteria (2013). There were 44 ESRs (n = 28 aseptic, n = 16 septic) and 46 CRPs (n = 29 aseptic, n = 17 septic) available for analysis. Two tailed t-tests were performed to compare the mean ESR and CRP in aseptic and septic cases. Receiver operator characteristic (ROC) curves were generated to obtain diagnostic cutoff thresholds using the Youden's Index (J) for ESR and CRP. The mean ESR was 50.3 ± 30.6 mm/h versus 15.4 ± 17.7 mm/h (p < 0.001), while the mean CRP was 29.9 ± 24.8 mg/L versus 4.1 ± 8.2 mg/L (p < 0.001) for septic and aseptic revisions, respectively. The diagnostic threshold for PJI determined by the ROC curve was 44 mm/h for ESR (sensitivity = 56.3%; specificity = 100.0%; J = 0.563; area under the curve (AUC) = 0.845), while it was 12.5 mg/L for CRP (sensitivity = 70.6%; specificity = 96.6%; J = 0.672; AUC = 0.896). For patients with HHA, an ESR of 44 mm/h was and a CRP of 12.5 mg/L was highly specific for PJI. The thresholds are similar to the MSIS thresholds currently published. Larger prospective trials are needed to establish more robust and conclusive diagnostic criteria for PJI in HHA, including investigations not only of ESR and CRP but synovial white blood cell count and synovial polymorphonuclear leukocytes % as well.

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