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1
Strauch, Ronda, Erkan Istanbulluoglu, Sai Siddhartha Nudurupati, Christina Bandaragoda, Nicole M. Gasparini, and Gregory E. Tucker. "A hydroclimatological approach to predicting regional landslide probability using Landlab." Earth Surface Dynamics 6, no. 1 (February 7, 2018): 49–75. http://dx.doi.org/10.5194/esurf-6-49-2018.
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Abstract. We develop a hydroclimatological approach to the modeling of regional shallow landslide initiation that integrates spatial and temporal dimensions of parameter uncertainty to estimate an annual probability of landslide initiation based on Monte Carlo simulations. The physically based model couples the infinite-slope stability model with a steady-state subsurface flow representation and operates in a digital elevation model. Spatially distributed gridded data for soil properties and vegetation classification are used for parameter estimation of probability distributions that characterize model input uncertainty. Hydrologic forcing to the model is through annual maximum daily recharge to subsurface flow obtained from a macroscale hydrologic model. We demonstrate the model in a steep mountainous region in northern Washington, USA, over 2700 km2. The influence of soil depth on the probability of landslide initiation is investigated through comparisons among model output produced using three different soil depth scenarios reflecting the uncertainty of soil depth and its potential long-term variability. We found elevation-dependent patterns in probability of landslide initiation that showed the stabilizing effects of forests at low elevations, an increased landslide probability with forest decline at mid-elevations (1400 to 2400 m), and soil limitation and steep topographic controls at high alpine elevations and in post-glacial landscapes. These dominant controls manifest themselves in a bimodal distribution of spatial annual landslide probability. Model testing with limited observations revealed similarly moderate model confidence for the three hazard maps, suggesting suitable use as relative hazard products. The model is available as a component in Landlab, an open-source, Python-based landscape earth systems modeling environment, and is designed to be easily reproduced utilizing HydroShare cyberinfrastructure.
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Kwasniok, Frank. "Semiparametric maximum likelihood probability density estimation." PLOS ONE 16, no. 11 (November 9, 2021): e0259111. http://dx.doi.org/10.1371/journal.pone.0259111.
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A comprehensive methodology for semiparametric probability density estimation is introduced and explored. The probability density is modelled by sequences of mostly regular or steep exponential families generated by flexible sets of basis functions, possibly including boundary terms. Parameters are estimated by global maximum likelihood without any roughness penalty. A statistically orthogonal formulation of the inference problem and a numerically stable and fast convex optimization algorithm for its solution are presented. Automatic model selection over the type and number of basis functions is performed with the Bayesian information criterion. The methodology can naturally be applied to densities supported on bounded, infinite or semi-infinite domains without boundary bias. Relationships to the truncated moment problem and the moment-constrained maximum entropy principle are discussed and a new theorem on the existence of solutions is contributed. The new technique compares very favourably to kernel density estimation, the diffusion estimator, finite mixture models and local likelihood density estimation across a diverse range of simulation and observation data sets. The semiparametric estimator combines a very small mean integrated squared error with a high degree of smoothness which allows for a robust and reliable detection of the modality of the probability density in terms of the number of modes and bumps.
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Hassairi, A., and A. Masmoudi. "Extension of the variance function of a steep exponential family." Journal of Multivariate Analysis 92, no. 2 (February 2005): 239–56. http://dx.doi.org/10.1016/j.jmva.2003.09.010.
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Anees, M. T., K. Abdullah, M. N. M. Nawawi, N. A. N. Norulaini, M. I. Syakir, and A. K. M. Omar. "Soil erosion analysis by RUSLE and sediment yield models using remote sensing and GIS in Kelantan state, Peninsular Malaysia." Soil Research 56, no. 4 (2018): 356. http://dx.doi.org/10.1071/sr17193.
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The present study used pixel-based soil erosion analysis through Revised Universal Soil Loss Equation (RUSLE) and a sediment yield model. The main motive of this study is to find soil erosion probability zones and accordingly prioritise watersheds using remote sensing and Geographic Information System (GIS) techniques in Kelantan state, Peninsular Malaysia. The catchment was divided into 82 watersheds and soil loss of the catchment was calculated. Soil loss and sediment yield were divided into five categories ranging from very low to very high. Maximum area of the very high soil-loss category was observed in uncultivated land and the maximum area of very low soil-loss category was in forest. Soil erosion probability zones were also divided into five categories in which 36.1% of the area experienced zero soil erosion and 20.1% and 17.8% represented very high and high probability zones respectively. The maximum very high and high probability zones were 61.6% and 28.5% of the watershed area respectively. Prioritisation was according to the area covered by very high and high soil erosion probability zones, which showed that out of 82 watersheds, two had the very high and high priority categories respectively. The overall results indicate that high rainfall and agricultural activities enhanced the soil erosion rate on steep slopes in the catchment. Pixel-based soil erosion analysis through remote sensing and GIS was a very effective tool in finding accurate causes of soil erosion. Furthermore, it was suggested that agricultural activities and deforestation should be stopped on steep slopes because of their contribution in increasing soil erosion.
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Tolaney, Sara M., Elizabeth Garrett-Mayer, Julia White, Victoria S. Blinder, Jared C. Foster, Laleh Amiri-Kordestani, E. Shelley Hwang, et al. "Updated Standardized Definitions for Efficacy End Points (STEEP) in Adjuvant Breast Cancer Clinical Trials: STEEP Version 2.0." Journal of Clinical Oncology 39, no. 24 (August 20, 2021): 2720–31. http://dx.doi.org/10.1200/jco.20.03613.
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PURPOSE The Standardized Definitions for Efficacy End Points (STEEP) criteria, established in 2007, provide standardized definitions of adjuvant breast cancer clinical trial end points. Given the evolution of breast cancer clinical trials and improvements in outcomes, a panel of experts reviewed the STEEP criteria to determine whether modifications are needed. METHODS We conducted systematic searches of ClinicalTrials.gov for adjuvant systemic and local-regional therapy trials for breast cancer to investigate if the primary end points reported met STEEP criteria. On the basis of common STEEP deviations, we performed a series of simulations to evaluate the effect of excluding non–breast cancer deaths and new nonbreast primary cancers from the invasive disease–free survival end point. RESULTS Among 11 phase III breast cancer trials with primary efficacy end points, three had primary end points that followed STEEP criteria, four used STEEP definitions but not the corresponding end point names, and four used end points that were not included in the original STEEP manuscript. Simulation modeling demonstrated that inclusion of second nonbreast primary cancer can increase the probability of incorrect inferences, can decrease power to detect clinically relevant efficacy effects, and may mask differences in recurrence rates, especially when recurrence rates are low. CONCLUSION We recommend an additional end point, invasive breast cancer–free survival, which includes all invasive disease–free survival events except second nonbreast primary cancers. This end point should be considered for trials in which the toxicities of agents are well-known and where the risk of second primary cancer is small. Additionally, we provide end point recommendations for local therapy trials, low-risk populations, noninferiority trials, and trials incorporating patient-reported outcomes.
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Zhang, Jing, Lei Wan, Yan-Ling Dong, and Li-Xin Xie. "Outcomes of different lines of keratoconus management in a tertiary eye center in north China." International Journal of Ophthalmology 15, no. 4 (April 18, 2022): 568–75. http://dx.doi.org/10.18240/ijo.2022.04.07.
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AIM: To evaluate the treatment selections and outcomes of keratoconus and discuss the grading treatment of keratoconus. METHODS: Medical records of 1162 patients (1863 eyes) with keratoconus treated with rigid gas permeable (RGP), corneal collagen crosslinking, and keratoplasty were reviewed. The patients were grouped according to the CLEK Study. The advanced group was further divided into a <60 D group and >60 D group. The best-corrected visual acuity (BCVA) and topographic data before and after treatment were recorded. RESULTS: In the 761 eyes with steep K<52 D, nonsurgical management accounted for 83.4%, while in the 735 eyes with steep K>60 D, surgical management accounted for 90.6%. A total of 618 eyes had improved BCVA at the final follow-up point (>18mo, P<0.001). When steep K was <52 D, the BCVA in the RGP group was better than those with lamellar keratoplasty (LKP; P=0.028). When steep K was >52 D, the BCVA and topographic astigmatism outcomes showed no differences among the treatment groups. When steep K was >60 D, the BCVA in eyes treated with LKP was worse than those with steep K<60 D (P=0.025). The incidence of steep K progression in the RGP group was higher in advanced group (20.0% vs 10.8%, P=0.019). The probability of future keratoplasty in RGP was higher in advanced group (14.8% vs 7.0%, P=0.027). The incidence of steep K progression in the corneal collagen crosslinking (CXL) group was higher in advanced group (32.3% vs 8.5%, P=0.007). Multivariate logistic regression revealed the following related factors for treatment options: steep K [odds ratio (OR)=1.208, 95%CI: 1.052-1.387], TA (OR=1.171, 95%CI: 1.079-1.270), and TCT (OR=0.978, 95%CI: 0.971-0.984). The level of steep K, TA, and TCT all relates to the treatment choices of both keratoplasty and non-keratoplasty, while steep K provided the highest diagnostic accuracy (AUC=0.947, P<0.001). CONCLUSION: Steep K is an important grading treatment indicator. When steep K is <52 D, RGP lenses should be recommended. It is the best time for LKP when the steep K ranges from 52 to 60 D.
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Tao, Hongliang, Guangli Xu, Jingwen Meng, Ronghe Ma, and Jiaxing Dong. "Stability Assessment of High and Steep Cutting Rock Slopes with the SSPC Method." Advances in Civil Engineering 2021 (April 20, 2021): 1–10. http://dx.doi.org/10.1155/2021/8889526.
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The stability of high rock slopes has become a key engineering geological problem in the construction of important projects in mountainous areas. The original slope stability probability classification (SSPC) system, presented by Hack, has made obvious progress and been widely used in rock slope stability analysis. However, the selection and determination of some evaluation indexes in the original SSPC method are usually subjective, such as intact rock strength and weathering degree. In this study, the SSPC method based on geological data obtained in the prospecting tunnels was presented and applied. According to the field survey and exploration of the prospecting tunnels, the weathering degree of the slope rock mass was evaluated. The empirical equation for the maximum stable height of the slope was applied to the slope stability evaluation in the presented SSPC method. Then, the slope stability probability of numerous cutting slopes in the sandstone unit was evaluated using the presented system. Results of the Geostudio software based on the limited equilibrium analysis of the investigated slopes were compared with the results obtained by the SSPC method. The results indicate that the SSPC method is a useful tool for the stability prediction of high and steep rock slopes.
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Tiwari, Ram Chandra, and Netra Prakash Bhandary. "Stochastic Finite Element Analysis of Root-Reinforcement Effects in Long and Steep Slopes." Geotechnics 3, no. 3 (August 23, 2023): 829–53. http://dx.doi.org/10.3390/geotechnics3030045.
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This article introduces a novel numerical scheme within the finite element method (FEM) to study soil heterogeneity, specifically focusing on the root–soil matrix in fracture treatments. Material properties, such as Young’s modulus of elasticity, cohesion, and the friction angle, are considered as randomly distributed variables. To address the inherent uncertainty associated with these distributions, a Monte Carlo simulation is employed. By incorporating the uncertainties related to material properties, particularly the root component that contributes to soil heterogeneity, this article provides a reliable estimation of the factor of safety, failure surface, and slope deformation, all of which demonstrate a progressive behavior. The probability distribution curve for the factor of safety (FOS) reveals that an increase in the root area ratio (RAR) results in a narrower range and greater certainty in the population mean, indicating reduced material variation. Moreover, as the slope angle increases, the sample mean falls within a wider range of the probability density curve, indicating an enhanced level of material heterogeneity. This heterogeneity amplifies the level of uncertainty when predicting the factor of safety, highlighting the crucial importance of accurate information regarding heterogeneity to enhancing prediction accuracy.
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Tromans, Peter S., and Luc Vanderschuren. "A Spectral Response Surface Method for Calculating Crest Elevation Statistics." Journal of Offshore Mechanics and Arctic Engineering 126, no. 1 (February 1, 2004): 51–53. http://dx.doi.org/10.1115/1.1641390.
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The statistics of wave crest elevation in a random, directionally spread sea are calculated using a novel approach. The nonlinearity of steep waves is modelled to second order using Sharma and Dean kinematics and a spectral response surface method is used to deduce the crest elevation corresponding to a given probability of exceedance. The spectral response surface method works in the probability domain, making it several times faster than conventional time domain simulation of random waves. However, the results from the two methods show good agreement. As expected, nonlinearity makes extreme crests higher than the corresponding linear ones.
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Dahle, E. Aa, D. Myrhaug, and S. J. Dahl. "Probability of capsizing in steep and high waves from the side in open sea and coastal." Ocean Engineering 15, no. 2 (January 1988): 139–51. http://dx.doi.org/10.1016/0029-8018(88)90025-x.
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Victor, L., J. W. van der Meer, and P. Troch. "Probability distribution of individual wave overtopping volumes for smooth impermeable steep slopes with low crest freeboards." Coastal Engineering 64 (June 2012): 87–101. http://dx.doi.org/10.1016/j.coastaleng.2012.01.003.
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Taszarek, Mateusz, Harold E. Brooks, and Bartosz Czernecki. "Sounding-Derived Parameters Associated with Convective Hazards in Europe." Monthly Weather Review 145, no. 4 (April 1, 2017): 1511–28. http://dx.doi.org/10.1175/mwr-d-16-0384.1.
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Abstract Observed proximity soundings from Europe are used to highlight how well environmental parameters discriminate different kind of severe thunderstorm hazards. In addition, the skill of parameters in predicting lightning and waterspouts is also tested. The research area concentrates on central and western European countries and the years 2009–15. In total, 45 677 soundings are analyzed including 169 associated with extremely severe thunderstorms, 1754 with severe thunderstorms, 8361 with nonsevere thunderstorms, and 35 393 cases with nonzero convective available potential energy (CAPE) that had no thunderstorms. Results indicate that the occurrence of lightning is mainly a function of CAPE and is more likely when the temperature of the equilibrium level drops below −10°C. The probability for large hail is maximized with high values of boundary layer moisture, steep mid- and low-level lapse rates, and high lifting condensation level. The size of hail is mainly dependent on the deep layer shear (DLS) in a moderate to high CAPE environment. The likelihood of tornadoes increases along with increasing CAPE, DLS, and 0–1-km storm-relative helicity. Severe wind events are the most common in high vertical wind shear and steep low-level lapse rates. The probability for waterspouts is maximized in weak vertical wind shear and steep low-level lapse rates. Wind shear in the 0–3-km layer is the best at distinguishing between severe and extremely severe thunderstorms producing tornadoes and convective wind gusts. A parameter WMAXSHEAR multiplying square root of 2 times CAPE (WMAX) and DLS turned out to be the best in distinguishing between nonsevere and severe thunderstorms, and for assessing the severity of convective phenomena.
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Gallach-Sánchez, David, Peter Troch, and Andreas Kortenhaus. "AVERAGE AND WAVE-BY-WAVE OVERTOPPING PERFORMANCE OF STEEP LOW-CRESTED STRUCTURES." Coastal Engineering Proceedings, no. 36 (December 30, 2018): 77. http://dx.doi.org/10.9753/icce.v36.papers.77.
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Wave overtopping is a key process in coastal protection. The assessment of the wave overtopping rates is an important aspect in the design of coastal structures. In this paper, the focus is on steep low-crested structures, which include structures with steep slopes up to the limit case with vertical structures, with small relative freeboards up to the case with zero freeboards. This type of structures is of use for coastal protection in the case of sea level rise within climate change process and for overtopping wave energy converters. A literature review of the overtopping knowledge available for steep low-crested structures is carried out, identifying a knowledge gap. To fill this knowledge gap, 2D hydraulic model tests were performed at the wave flume of the Department of Civil Engineering at Ghent University, measuring wave conditions and the overtopping performance. Average and individual wave overtopping were analysed and compared to existing prediction formulae. Inaccuracies in the existing prediction formulae are detected and studied, and enhanced prediction formulae are presented for the average overtopping and the probability distribution of the individual overtopping volumes. The new prediction formulae improve the accuracy of wave overtopping volumes for steep low-crested structures range while maintaining the accuracy for other types of structures. The improved understanding of the overtopping behaviour allows a safer design of coastal structures.
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Magnin, Florence, Bernd Etzelmüller, Sebastian Westermann, Ketil Isaksen, Paula Hilger, and Reginald L. Hermanns. "Permafrost distribution in steep rock slopes in Norway: measurements, statistical modelling and implications for geomorphological processes." Earth Surface Dynamics 7, no. 4 (October 30, 2019): 1019–40. http://dx.doi.org/10.5194/esurf-7-1019-2019.
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Abstract. Permafrost in steep rock slopes has been increasingly studied since the early 2000s in conjunction with a growing number of rock slope failures, which likely resulted from permafrost degradation. In Norway, rock slope destabilization is a widespread phenomenon and a major source of risk for the population and infrastructure. However, a lack of precise knowledge of the permafrost distribution in steep slopes hinders the assessment of its role in these destabilizations. This study proposes the first nationwide permafrost probability map for the steep slopes of Norway (CryoWall map). It is based on a multiple linear regression model fitted with multi-annual rock surface temperature (RST) measurements, collected at 25 rock slope sites, spread across a latitudinal transect (59–69∘ N) over mainland Norway. The CryoWall map suggests that discontinuous permafrost widely occurs above 1300–1400 and 1600–1700 m a.s.l. in the north and south rock faces of southern Norway (59∘ N), respectively. This lower altitudinal limit decreases in northern Norway (70∘ N) by about 500±50 m, with a more pronounced decrease for south faces, as a result of the insolation patterns largely driven by midnight sun in summer and polar night in winter. Similarly, the mean annual RST differences between north and south faces of similar elevation range around 1.5 ∘C in northern Norway and 3.5 ∘C in southern Norway. The CryoWall map is evaluated against direct ice observations in steep slopes and discussed in the context of former permafrost studies in various types of terrain in Norway. We show that permafrost can occur at much lower elevations in steep rock slopes than in other terrains, especially in north faces. We demonstrate that the CryoWall map is a valuable basis for further investigations related to permafrost in steep slopes in terms of both practical concerns and fundamental science.
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Morelli, Federico Guglielmo, Michael Benzaquen, Marco Tarzia, and Jean-Philippe Bouchaud. "Confidence collapse in a multihousehold, self-reflexive DSGE model." Proceedings of the National Academy of Sciences 117, no. 17 (April 10, 2020): 9244–49. http://dx.doi.org/10.1073/pnas.1912280117.
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We investigate a multihousehold dynamic stochastic general equilibrium (DSGE) model in which past aggregate consumption impacts the confidence, and therefore consumption propensity, of individual households. We find that such a minimal setup is extremely rich and leads to a variety of realistic output dynamics: high output with no crises; high output with increased volatility and deep, short-lived recessions; and alternation of high- and low-output states where a relatively mild drop in economic conditions can lead to a temporary confidence collapse and steep decline in economic activity. The crisis probability depends exponentially on the parameters of the model, which means that markets cannot efficiently price the associated risk premium. We conclude by stressing that within our framework, narratives become an important monetary policy tool that can help steer the economy back on track.
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Hu, Bo-yi, Xin-min Wang, Shuai Li, Jian-wen Zhao, and Nyandwe Musonda Eugénie. "Stability Analysis and Confidence Level Evaluation of Backfill Mining under High and Steep Rock Slopes." Advances in Civil Engineering 2018 (October 21, 2018): 1–12. http://dx.doi.org/10.1155/2018/3029796.
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To extract the 6.3 million tons of high-quality phosphate resources, a stability analysis and confidence level evaluation of backfill mining under high and steep rock slopes (HSRS) were conducted using the Slide software and a Monte Carlo simulation. The geological model of HSRS was constructed based on a geotechnical investigation. A series of laboratory tests were conducted to obtain the engineering parameters of the rock mass, and the mechanism of action of the backfill mining method was analyzed. After the stability analysis, the average safety factors of HSRS for normal operation are 1.575 (backfill method) and 1.509 (open-stope method), and for seismic conditions, they are 1.470 (backfill method) and 1.380 (open-stope method). According to the confidence level evaluation, the average failure probability of HSRS by using the backfill mining method is 0.0143. The results showed that using the backfill mining method under HSRS had better seismic stability and lower potential levels of destruction than using the traditional open-stope mining method. In addition, the backfill mining method can prevent the development of a circular failure surface, reduce the destructive effect of mining to a minimum, and maintain the lower failure probability of HSRS.
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Grant, Gerold C., Paul Radomski, and Charles S. Anderson. "Using underwater video to directly estimate gear selectivity: the retention probability for walleye (Sander vitreus) in gill nets." Canadian Journal of Fisheries and Aquatic Sciences 61, no. 2 (February 1, 2004): 168–74. http://dx.doi.org/10.1139/f03-166.
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We developed a new approach for directly quantifying selection parameters for fishing gear using a dual underwater video camera apparatus and employed the method to estimate gill net retention probability for walleye (Sander vitreus). The method allows observation of fish behavior around fishing gear and estimation of the absolute probability of fish encountering, contacting, or being retained by the gear. We demonstrated the applicability of this method by quantifying the probability that walleye were retained in multifilament nylon gill nets after contacting the nets. Walleye with total lengths 2.49 times the perimeter of the mesh were most likely to be retained, and retention probability peaked at 0.60 (95% confidence interval 0.410.90), meaning 40% of walleye that were the ideal size for a given mesh escaped after contacting the net. Our empirically derived retention curve exhibited a steep ascending limb and strong positive skew because of walleye morphology and the tendency for larger walleye to be captured by tangling. Most walleye that avoided capture did not fully enter the mesh or backed out of the mesh after they became temporarily wedged or tangled.
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Meigs, Garrett W., Christopher J. Dunn, Sean A. Parks, and Meg A. Krawchuk. "Influence of topography and fuels on fire refugia probability under varying fire weather conditions in forests of the Pacific Northwest, USA." Canadian Journal of Forest Research 50, no. 7 (July 2020): 636–47. http://dx.doi.org/10.1139/cjfr-2019-0406.
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Fire refugia — locations that burn less severely or less frequently than surrounding areas — support late-successional and old-growth forest structure and function. This study investigates the influence of topography and fuels on the probability of forest fire refugia under varying fire weather conditions. We focused on recent large fires in Oregon and Washington, United States (n = 39 fires > 400 ha, 2004–2014). Our objectives were to (1) map fire refugia as a component of the burn severity gradient, (2) quantify the predictability of fire refugia as a function of prefire fuels and topography under moderate and high fire weather conditions, and (3) map the conditional probability of fire refugia to illustrate their spatial patterns in old-growth forests. Fire refugia exhibited higher predictability under relatively moderate fire weather conditions. Prefire live fuels were strong predictors of fire refugia, with higher refugia probability in forests with higher prefire biomass. In addition, fire refugia probability was higher in topographic settings with relatively northern aspects, steep catchment slopes, and concave topographic positions. Conditional probability maps revealed consistently higher fire refugia probability under moderate versus high fire weather scenarios. Results from this study inform conservation planning by determining late-successional forests most likely to persist as fire refugia despite increasing regional fire activity.
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Nakaya, Junko, Kazunari Sako, Shunsuke Mitsutani, and Ryoichi Fukagawa. "Hydrological Environment in Subsurface Steep Slope - Groundwater Flow Passageway on Slope Behind Kiyomizudera -." Journal of Disaster Research 6, no. 1 (February 1, 2011): 80–87. http://dx.doi.org/10.20965/jdr.2011.p0080.
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The hydrological environment must be understood before water flow can be adequately controlled to prevent slope failure without impacting unduly on the hydrological mountain slope environment. We conducted field studies to determine current sites and measurement of ground temperature 1 meter deep to clarify groundwater flow passageways on the slope behind the cultural heritage temple Kiyomizudera in Kyoto. Results showed anomalous temperature 1 meter deep bands on the slope and several springs that are extensions of these bands. Several of these bands coincide with terrain deformations such as gullies and slope failure scars indicating the probability of relationships between groundwater flow and topological deformation.
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Hardin, Jill, Suzan L. Carmichael, Steve Selvin, and Gary M. Shaw. "Trends in the Probability of Twins and Males in California, 1983–2003." Twin Research and Human Genetics 12, no. 1 (February 1, 2009): 93–102. http://dx.doi.org/10.1375/twin.12.1.93.
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AbstractThis study examines the probability of twins by birth year, maternal race–ethnicity, age, and parity and the influences of these demographic factors on the probability of male in twins and singletons in a large, racially diverse population. Recent publications note steep increases in twin births while the probability of male births has been reported to vary by parental race–ethnicity and age and birth order. Probability of male stratified by plurality has not been investigated in California prior to this study. Cubic spline estimates and Poisson regression techniques were employed to describe trends in twins and males using California vital statistics birth and fetal death records over the period from 1983–2003. This study includes 127,787 twin pair and 11,025,106 singleton births. The probability of twins varied by birth year, maternal race–ethnicity, age, and parity. The probability of twins increased by 10.1% from 1983–1992 and increased by 20.1% from 1993–2003, nearly doubling the previous increase. All maternal race–ethnicity groups showed increases in probability of twins with increasing maternal age. Parous women compared to nulliparous women had larger increases in the probability of twins. The probability of males in twins decreased from 1983–1992 and increased from 1993–2003; while in singletons the probability appeared unchanged. These findings show increases in the probability of twins in California from 1983–2003 and identify maternal age, race–ethnicity, and parity groups most likely to conceive twins. The cause of the increase in twins is unknown but coincides with trends towards delayed childbearing and increased use of subfertility treatments.
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Kupferschmid Albisetti, Andrea D., Peter Brang, Walter Schönenberger, and Harald Bugmann. "Decay of Picea abies snag stands on steep mountain slopes." Forestry Chronicle 79, no. 2 (April 1, 2003): 247–52. http://dx.doi.org/10.5558/tfc79247-2.
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In a 30-ha Picea abies mountain forest in the Swiss Alps, almost all trees were killed by bark beetles (Ips typographus) between 1992 and 1996. Snag decay was studied using full-callipering within transects, and the height of lying logs above ground level was studied using the line intersect method. None of the dead trees had been uprooted, but 75% were found broken in 2000. The probability of snag breakage was independent of both tree diameter and time since stand death, but 28% of the snags broke close to the ground during a storm in December 1999. The log sections that were not in direct contact with the ground (73% of the log length sampled) were on average 85 cm above the soil surface in 2001. The orientation of the logs could be explained with the prevailing wind direction even on this steep slope. Leaving snag stands unharvested in P. abies forests on such slopes is likely to result in effective protection against rockfall and avalanche release for about 30 years. Key words: Norway spruce, bark beetle, decay process, rockfall, avalanche, mountain forest, Switzerland, decomposition, coarse woody debris
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Li, Liang-Liang, and Xiao-Fang Wang. "Analytical model for scattering effect of energetic charged-particle beam on radiography in steep density gradient region." Acta Physica Sinica 71, no. 11 (2022): 115201. http://dx.doi.org/10.7498/aps.70.20212269.
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Energetic charged-particle beams produced from ultrashort ultra-intense laser plasma interactions play a vital role in charged-particle radiography. When such an energetic beam penetrates through a foil target, its energy loss is negligible, and the main physics process is small-angle scattering. owing to this scattering effect, charged-particle radiography of a target with a transversely distributed steep density gradient region will produce a modulation structure in the fluence distribution on the detection plane, which can be used to diagnose the steep density gradient region. In the past, the theoretical work on the scattering effect and the resulting modulation structure was done with Monte-Carlo simulations, which costed a lot of computing time and the studied parameter range was limited. In the present work, an analytical model is developed to deal with the scattering effect inside the target and the modulation structure on the detection plane in radiography, which can quickly present the results that coincide with Monte-Carlo simulations very well. By using this analytical model, the characteristics of modulation structures are analyzed. A dimensionless characteristic parameter related to radiography conditions is put forward, and its range determines different modulation structures and also the probability of diagnosing a steep density gradient region with a width of less than 2 μm.
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Parisien, Marc-André, Gregg R. Walker, John M. Little, Brian N. Simpson, Xianli Wang, and Daniel D. B. Perrakis. "Considerations for modeling burn probability across landscapes with steep environmental gradients: an example from the Columbia Mountains, Canada." Natural Hazards 66, no. 2 (November 19, 2012): 439–62. http://dx.doi.org/10.1007/s11069-012-0495-8.
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Gemmrich, J., and C. Garrett. "Dynamical and statistical explanations of observed occurrence rates of rogue waves." Natural Hazards and Earth System Sciences 11, no. 5 (May 18, 2011): 1437–46. http://dx.doi.org/10.5194/nhess-11-1437-2011.
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Abstract. Extreme surface waves occur in the tail of the probability distribution. Their occurrence rate can be displayed effectively by plotting ln(–ln P), where P is the probability of the wave or crest height exceeding a particular value, against the logarithm of that value. A Weibull distribution of the exceedance probability, as proposed in a standard model, then becomes a straight line. Earlier North Sea data from an oil platform suggest a curved plot, with a higher occurrence rate of extreme wave and crest heights than predicted by the standard model. The curvature is not accounted for by second order corrections, non-stationarity, or Benjamin-Feir instability, though all of these do lead to an increase in the exceedance probability. Simulations for deep water waves suggest that, if the waves are steep, the curvature may be explained by including up to fourth order Stokes corrections. Finally, the use of extreme value theory in fitting exceedance probabilities is shown to be inappropriate, as its application requires that not just N, but also lnN, be large, where N is the number of waves in a data block. This is unlikely to be adequately satisfied.
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Innes, J. L. "Textural properties of regoliths on vegetated steep slopes in upland regions, Scotland." Transactions of the Royal Society of Edinburgh: Earth Sciences 77, no. 3 (1986): 241–50. http://dx.doi.org/10.1017/s0263593300010877.
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ABSTRACTThe textural properties of many sediments provide a good indication of their provenance, but surprisingly little information is available on the transitional stages between the breakdown of a rock and the incorporation of the material into a fluvial sediment. These transitional stages are important as certain fractions (particularly the finer ones) may be selectively removed. Regoliths developed on steep slopes represent an early stage in the debris cascade and they are here examined in detail to assess the role of parent lithology on the textural properties of the regolith. There are substantial variations between lithologies, although the majority of regoliths are dominated by coarser fractions and are poorly sorted. Most particle size distributions show some degree of fit to both log-normal probability distributions and Rosin distributions. Differences from these can be ascribed to the processes operating on steep slopes, particularly the influx of sand- and silt-sized material by colluvial processes and the removal of clay-sized material by leaching. The regoliths form a distinct facies type which may be recognisable in the geological record.
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Wu, Chun-Yi, and Yen-Chu Yeh. "A Landslide Probability Model Based on a Long-Term Landslide Inventory and Rainfall Factors." Water 12, no. 4 (March 26, 2020): 937. http://dx.doi.org/10.3390/w12040937.
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The prediction and advanced warning of landslide hazards in large-scale areas must deal with a large amount of uncertainty, therefore a growing number of studies are using stochastic models to analyze the probability of landslide occurrences. In this study, we used a modified Thiessen’s polygon method to divide the research area into several rain gauge control areas, and divided the control areas into slope units reflecting the topographic characteristics to enhance the spatial resolution of a landslide probability model. We used a 2000–2015 long-term landslide inventory, daily rainfall, and effective accumulated rainfall to estimate the rainfall threshold that can trigger landslides. We then employed a Poisson probability model and historical rainfall data from 1987 to 2016 to calculate the exceedance probability that rainfall events will exceed the threshold value. We calculated the number of landslides occurring from the events when rainfall exceeds the threshold value in the slope units to estimate the probability that a landslide will occur in this situation. Lastly, we employed the concept of conditional probability by multiplying this probability with the exceedance probability of rainfall events exceeding the threshold value, which yielded the probability that a landslide will occur in each slope unit for one year. The results indicated the slope units with high probability that at least one rainfall event will exceed the threshold value at the same time that one landslide will occur within any one year are largely located in the southwestern part of the Taipei Water Source Domain, and the highest probability is 0.26. These slope units are located in parts of the study area with relatively weak lithology, high elevations, and steep slopes. Compared with probability models based solely on landslide inventories, our proposed landslide probability model, combined with a long-term landslide inventory and rainfall factors, can avoid problems resulting from an incomplete landslide inventory, and can also be used to estimate landslide occurrence probability based on future potential changes in rainfall.
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Krishna, Gopal, H. Steppe, T. Ghosh, and L. Saripalli. "A statistical analysis of the radio properties of a large sample of 374 optically selected quasars." Symposium - International Astronomical Union 119 (1986): 111–12. http://dx.doi.org/10.1017/s0074180900152404.
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Using a large, unbiased sample of 374 optically selected QSOs, of which 54 are radio detected, we have computed for different redshift ranges the probability distribution function φ (R) of R defined as the ratio of monochromatic luminosities at 15 GHz and 2500 Å in the QSO's rest frame. A significant variation of φ (R) with redshift is noticed. At small redshifts (z < 0.5), the distinctive feature of φ (R) is a peak near R∼102, arising due to the QSOs having steep radio spectrum(αr<−0.5).
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Mishel, Emma, Paula England, Jessie Ford, and Mónica L. Caudillo. "Cohort Increases in Sex with Same-Sex Partners: Do Trends Vary by Gender, Race, and Class?" Gender & Society 34, no. 2 (January 23, 2020): 178–209. http://dx.doi.org/10.1177/0891243219897062.
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We examine change across U.S. cohorts born between 1920 and 2000 in their probability of having had sex with same-sex partners in the last year and since age 18. Using data from the 1988–2018 General Social Surveys, we explore how trends differ by gender, race, and class background. We find steep increases across birth cohorts in the proportion of women who have had sex with both men and women since age 18, whereas increases for men are less steep. We suggest that the trends reflect an increasingly accepting social climate, and that women’s steeper trend is rooted in a long-term asymmetry in gender change, in which nonconformity to gender norms is more acceptable for women than men. We also find evidence that, among men, the increase in having had sex with both men and women was steeper for black than for white men, and for men of lower socioeconomic status; we speculate that the rise of mass incarceration among less privileged men may have influenced this trend.
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Zhao, Yifei, Jingru Li, and Xinzhi Ying. "Study on Risk of Long-Steep Downgrade Sections of Expressways Based on a Fuzzy Hierarchy Comprehensive Evaluation." Applied Sciences 12, no. 12 (June 10, 2022): 5924. http://dx.doi.org/10.3390/app12125924.
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The long-steep downgrade sections of expressways are characterized by a large elevation difference, poor horizontal and vertical alignment, and the easy failure of brakes on large trucks. They are sections with a high overall operation safety risk. It is necessary to strengthen the research on traffic risk evaluation. In order to study the traffic safety risks of long-steep downgrade parts of expressways, the fuzzy hierarchical comprehensive evaluation method is used to establish the calculation model. First, an evaluation index system including the target level, rule level, first-level index level and second-level index level is established. The qualitative and quantitative indicators are processed by the set value statistical method and the linear standard method, respectively, so that all indicators can be quantitatively evaluated together. Then, each indicator is assigned a score and divided into five risk levels, and a ridge-shaped fuzzy distribution is used to constitute a membership function for each level. A hierarchical structure model is established with the analytic hierarchy process to determine the affiliation between the upper and lower levels, and the relative weight of each level to the upper level also can be obtained. Finally, according to the hierarchical relevance of each evaluation indicator, a three-level fuzzy comprehensive evaluation model is constructed. The traffic risk evaluation level for long-steep downgrade sections can be obtained, and the probability of the corresponding risk evaluation level can be calculated. Through the risk evaluation of the long-steep downgrade sections of the Fuzhou Yinchuan Expressway in China, this shows that the risk evaluation conclusion obtained by using this evaluation method is consistent with the actual traffic safety situation, which shows that the traffic safety risk evaluation model based on a fuzzy hierarchy comprehensive evaluation is operable.
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Goda, Gopi Shah, John B. Shoven, and Sita Nataraj Slavov. "What Explains Changes in Retirement Plans during the Great Recession?" American Economic Review 101, no. 3 (May 1, 2011): 29–34. http://dx.doi.org/10.1257/aer.101.3.29.
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We examine changes in subjective probabilities regarding retirement between the 2006 and 2008 waves of the Health and Retirement Study. Using a first-difference approach to eliminate individual heterogeneity, we find that the steep drop in asset prices in 2008 increased the reported probability of working at age 62 during the Great Recession. Increasing unemployment at least partly attenuated this effect, but subjective probabilities of working did not respond to changes in housing markets. Older workers' probabilities of working were more sensitive to fluctuations in the stock market, but less responsive to changes in labor market conditions.
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Morse, Bruce W., and Herbert M. Kulman. "A Method of Hazard-Rating White Spruce Plantations For Yellowheaded Spruce Sawfly Defoliation." Northern Journal of Applied Forestry 3, no. 3 (September 1, 1986): 104–5. http://dx.doi.org/10.1093/njaf/3.3.104.
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Abstract A hazard-rating model for defoliation by the yellowheaded spruce sawfly was developed and validated using 25 white spruce plantations in north central Minnesota. The dependent variable was degree of defoliation, and the independent variables, as measured from small-format aerial photographs, were steepness and slope aspect. The site characteristics and defoliation were correlated using a maximum likelihood logistic regression. The final model determined that steep, south-facing slopes had the highest probability of sawfly-caused defoliation. Identification of high-hazard sites should be a major component of a management plan for this pest. North. J. Appl. For. 3:104-105, Sept. 1986.
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Kopta, Daniel. "Impact of the structure of agricultural production to the financial health of farms." Acta Universitatis Agriculturae et Silviculturae Mendelianae Brunensis 61, no. 7 (2013): 2317–25. http://dx.doi.org/10.11118/actaun201361072317.
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The first part of the paper deals with the influence of individual commodities on the profitability and risks of farms. Production structure was given thought share of twelve basic crops in total agricultural production yield. Volume of accumulated profit for five-year income was chosen as viability criterion. The research did not show that specialization in one of the commodities had significantly influenced achieved profitability. The only exception is the production of milk, which clearly lead to lower profitability. Production structure determined the risk of farms. Farms were constantly threatened by both negative profitability, and also steep fluctuations of cash flow (in other of long-term positive profitability), leading to temporary loss of solvency. The analysis showed that different types of production structures lead to different types of threats. The probability of falling into production losses, or that the loss is so great that not even cover variable costs (a farm finds itself under the point of termination of production) was calculated using the EaR method. The results again supported previous findings. Loss is highly likely to be achieved in commodities of animal production. For commodities of crop production the probability of loss was roughly a half, but the probability of exceeding a period of variable costs is higher.
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Zhao-Guo, Chen. "Consistent estimates for hidden frequencies in a linear process." Advances in Applied Probability 20, no. 2 (June 1988): 295–314. http://dx.doi.org/10.2307/1427391.
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Traditional methods for detecting the hidden frequencies in white or coloured noise is based on the distribution of periodogram ordinates Ι (2πj/N) and hypothesis testing. The power is low when a hidden frequency falls midway between two 2nj/N and it is difficult to discuss the consistency of the procedures. Using theorems on almost sure convergence of the periodogram, this paper offers a procedure for detecting and estimating the hidden frequencies, and discusses the consistency and the rates of convergence. Simulation shows very good results, when the spectrum of the noise is not too steep.
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Zhao-Guo, Chen. "Consistent estimates for hidden frequencies in a linear process." Advances in Applied Probability 20, no. 02 (June 1988): 295–314. http://dx.doi.org/10.1017/s0001867800016980.
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Traditional methods for detecting the hidden frequencies in white or coloured noise is based on the distribution of periodogram ordinates Ι (2πj/N) and hypothesis testing. The power is low when a hidden frequency falls midway between two 2nj/N and it is difficult to discuss the consistency of the procedures. Using theorems on almost sure convergence of the periodogram, this paper offers a procedure for detecting and estimating the hidden frequencies, and discusses the consistency and the rates of convergence. Simulation shows very good results, when the spectrum of the noise is not too steep.
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Xie, Zhen Hua, Dong Yang, Sha Sha Liang, and Zhi Yun Jia. "Research on Number of High-Pressure Grouting of Hierarchical Multiple for Slope Based on Reliability Analysis." Applied Mechanics and Materials 716-717 (December 2014): 363–69. http://dx.doi.org/10.4028/www.scientific.net/amm.716-717.363.
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The technology of hierarchical multiple high-pressure grouting is an effective approach to manage high and steep slope of broken rock mass. The number of grouting is one of the key parameters of this technology. By the analysis of mechanics and grouting theory, the anchoring effect mainly is affected by anchor slurry vein and the contact area with rock mass. Based on the system analysis of slurry vein development for first time and many times high-pressure grouting, the process flow for hierarchical multiple high-pressure grouting is put forward. Serve the rock permeability changes before and after grouting as an indicator measuring slurry and rock surface area, the method of determining grouting number based on the reliable probability is got. Combined with the engineering example of Shouyun Iron Mine, this paper puts forward the reliability criteria of working state of hierarchical multiple high-pressure grouting. Through the probability calculation, the best number of grouting is 4 times. The tests of permeability of rock mass and drawing force verify the accuracy of this determination method.
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Hoppa, Michael B., and Timothy A. Ryan. "Alpha2Delta Calcium Channel Subunit Constrains Steep Dependence of Release Probability on Calcium Channel Density through Coupling to Kv1.1 at Nerve Terminals." Biophysical Journal 104, no. 2 (January 2013): 499a. http://dx.doi.org/10.1016/j.bpj.2012.11.2754.
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Benevides, P., J. Catalao, and P. M. A. Miranda. "On the inclusion of GPS precipitable water vapour in the nowcasting of rainfall." Natural Hazards and Earth System Sciences 15, no. 12 (December 9, 2015): 2605–16. http://dx.doi.org/10.5194/nhess-15-2605-2015.
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Abstract. The temporal behaviour of precipitable water vapour (PWV) retrieved from GPS delay data is analysed in a number of case studies of intense precipitation in the Lisbon area, in the period 2010–2012 and in a continuous annual cycle of 2012 observations. Such behaviour is found to correlate positively with the probability of precipitation, especially in cases of severe rainfall. The evolution of the GPS PWV in a few stations is analysed by a least-squares fitting of a broken line tendency, made by a temporal sequence of ascents and descents over the data. It is found that most severe rainfall events occur in descending trends after a long ascending period and that the most intense events occur after steep ascents in PWV. A simple algorithm, forecasting rain in the 6 h after a steep ascent of the GPS PWV in a single station, is found to produce reasonable forecasts of the occurrence of precipitation in the nearby region, without significant misses in what concerns larger rain events, but with a substantial amount of false alarms. It is suggested that this method could be improved by the analysis of 2-D or 3-D time-varying GPS PWV fields or by its joint use with other meteorological data relevant to nowcast precipitation.
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Benevides, P., J. Catalao, and P. M. A. Miranda. "On the inclusion of GPS precipitable water vapour in the nowcasting of rainfall." Natural Hazards and Earth System Sciences Discussions 3, no. 6 (June 12, 2015): 3861–95. http://dx.doi.org/10.5194/nhessd-3-3861-2015.
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Abstract. The temporal behaviour of Precipitable Water Vapour (PWV) retrieved from GPS delay data is analysed in a number of case studies of intense precipitation in the Lisbon area, in the period 2010–2012, and in a continuous annual cycle of 2012 observations. Such behaviour is found to correlate positively with the probability of precipitation, especially in cases of severe rainfall. The evolution of the GPS PWV in a few stations is analysed by a least-squares fitting of a broken line tendency, made by a temporal sequence of ascents and descents over the data. It is found that most severe rainfall event occurs in descending trends after a long ascending period, and that the most intense events occur after steep ascents in PWV. A simple algorithm, forecasting rain in the 6 h after a steep ascent of the GPS PWV in a single station is found to produce reasonable forecasts of the occurrence of precipitation in the nearby region, without significant misses in what concerns larger rain events, but with a substantial amount of false alarms. It is suggested that this method could be improved by the analysis of 2-D or 3-D time varying GPS PWV fields, or by its joint use with other meteorological data relevant to nowcast precipitation.
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Collins, L., R. A. Bradstock, and T. D. Penman. "Can precipitation influence landscape controls on wildfire severity? A case study within temperate eucalypt forests of south-eastern Australia." International Journal of Wildland Fire 23, no. 1 (2014): 9. http://dx.doi.org/10.1071/wf12184.
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The environmental, economic and social impacts of wildfires depend on spatial patterns of fire severity. An understanding as to how drivers of fire severity vary across broad vegetation communities exists. However, examination of variation within communities in response to gradients of moisture has received little attention so far. This study examined whether relationships between environmental variables (i.e. fire weather, topography and fuel age) and fire severity were modified by increasing mean annual precipitation. Understorey fires were more likely to occur in young fuels (i.e. <5 years since fire) in drier sites, although this effect diminished as precipitation increased. The probability of occurrence of understorey fires under non-extreme weather and on steep slopes was reduced in wetter areas. Relationships between crown fire and weather, topography and fuel age were largely unaltered by the precipitation gradient, with only a marginally significant interaction occurring between weather and mean annual precipitation. Greater fine fuel accumulation associated with increased precipitation presumably reduced fuel limitations imposed by environmental factors (i.e. fire weather, slope, fuel age), altering their relative control on the probability of understorey fire. The probability of crown fires is predominantly driven by fire weather and is consequently less sensitive to precipitation gradients. Consideration of precipitation gradients will be necessary when identifying controls of fire severity and devising effective fire management strategies.
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Shemer, L. "On Benjamin-Feir instability and evolution of a nonlinear wave with finite-amplitude sidebands." Natural Hazards and Earth System Sciences 10, no. 11 (November 30, 2010): 2421–27. http://dx.doi.org/10.5194/nhess-10-2421-2010.
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Abstract. In the past decade it became customary to relate the probability of appearance of extremely steep (the so-called freak, or rogue waves) to the value of the Benjamin-Feir Index (BFI) that represents the ratio of wave nonlinearity to the spectral width. This ratio appears naturally in the cubic Schrödinger equation that describes evolution of unidirectional narrow-banded wave field. The notion of this index stems from the Benjamin-Feir linear stability analysis of Stokes wave. The application of BFI to evaluate the evolution of wave fields, with non-vanishing amplitudes of sideband disturbances, is investigated using the Zakharov equation as the theoretical model. The present analysis considers a 3-wave system for which the exact analytical solution of the model equations is available.
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Jahanfar, Ali, Mohsen Amirmojahedi, Bahram Gharabaghi, Brajesh Dubey, Edward McBean, and Dinesh Kumar. "A novel risk assessment method for landfill slope failure: Case study application for Bhalswa Dumpsite, India." Waste Management & Research: The Journal for a Sustainable Circular Economy 35, no. 3 (February 2, 2017): 220–27. http://dx.doi.org/10.1177/0734242x16686412.
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Rapid population growth of major urban centres in many developing countries has created massive landfills with extraordinary heights and steep side-slopes, which are frequently surrounded by illegal low-income residential settlements developed too close to landfills. These extraordinary landfills are facing high risks of catastrophic failure with potentially large numbers of fatalities. This study presents a novel method for risk assessment of landfill slope failure, using probabilistic analysis of potential failure scenarios and associated fatalities. The conceptual framework of the method includes selecting appropriate statistical distributions for the municipal solid waste (MSW) material shear strength and rheological properties for potential failure scenario analysis. The MSW material properties for a given scenario is then used to analyse the probability of slope failure and the resulting run-out length to calculate the potential risk of fatalities. In comparison with existing methods, which are solely based on the probability of slope failure, this method provides a more accurate estimate of the risk of fatalities associated with a given landfill slope failure. The application of the new risk assessment method is demonstrated with a case study for a landfill located within a heavily populated area of New Delhi, India.
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Ardissino, Gianluigi, Sara Testa, Valeria Daccò, Fabio Paglialonga, Sara Viganò, Cristina Felice-Civitillo, Francesco Battaglino, et al. "Puberty is associated with increased deterioration of renal function in patients with CKD: data from the ItalKid Project." Archives of Disease in Childhood 97, no. 10 (July 25, 2012): 885–88. http://dx.doi.org/10.1136/archdischild-2011-300685.
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ObjectiveTo analyse the timing of end stage renal disease in children with chronic kidney disease (CKD).DesignA population-based cohort study.SettingA nationwide registry (ItalKid Project) collecting information on all patients with CKD aged <20 years.Patients935 children with CKD secondary to renal hypodysplasia with or without urologic malformation. In a subgroup of patients (n=40) detailed pubertal staging was analysed in relation to CKD progression.Main outcome measuresKidney survival (KS) was estimated using renal replacement therapy (RRT) as the end-point. Puberty was staged by identifying the pubertal growth spurt.ResultsA non-linear decline in the probability of KS was observed, with a steep decrease during puberty: the probability of RRT was estimated to be 9.4% and 51.8% during the first and second decades of life, respectively. A break-point in the KS curve was identified at 11.6 and 10.9 years of age in male and female patients, respectively.ConclusionsThe present analysis suggests that puberty is associated with increased deterioration of renal function in CKD. The mechanism(s) underlying this unique and specific (to children) pattern of progression have not yet been identified, but it may be that sex hormones play a role in this puberty-related progression of CKD.
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Rossi, Fernando, Johannes Breidenbach, Stefano Puliti, Rasmus Astrup, and Bruce Talbot. "Assessing Harvested Sites in a Forested Boreal Mountain Catchment through Global Forest Watch." Remote Sensing 11, no. 5 (March 6, 2019): 543. http://dx.doi.org/10.3390/rs11050543.
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Global Forest Watch (GFW) provides a global map of annual forest cover loss (FCL) produced from Landsat imagery, offering a potentially powerful tool for monitoring changes in forest cover. In managed forests, FCL primarily provides information on commercial harvesting. A semi-autonomous method for providing data on the location and attributes of harvested sites at a landscape level was developed which could significantly improve the basis for catchment management, including risk mitigation. FCL in combination with aerial images was used for detecting and characterising harvested sites in a 1607 km2 mountainous boreal forest catchment in south-central Norway. Firstly, the forest cover loss map was enhanced (FCLE) by removing small isolated forest cover loss patches that had a high probability of representing commission errors. The FCLE map was then used to locate and assess sites representing annual harvesting activity over a 17-year period. Despite an overall accuracy of >98%, a kappa of 0.66 suggested only a moderate quality for detecting harvested sites. While errors of commission were negligible, errors of omission were more considerable and at least partially attributed to the presence of residual seed trees on the site after harvesting. The systematic analysis of harvested sites against aerial images showed a detection rate of 94%, but the area of the individual harvested site was underestimated by 29% on average. None of the site attributes tested, including slope, area, altitude, or site shape index, had any effect on the accuracy of the area estimate. The annual harvest estimate was 0.6% (standard error 12%) of the productive forest area. On average, 96% of the harvest was carried out on flat to moderately steep terrain (<40% slope), 3% on steep terrain (40% to 60% slope), and 1% on very steep terrain (>60% slope). The mean area of FCLE within each slope category was 1.7 ha, 0.9 ha, and 0.5 ha, respectively. The mean FCLE area increased from 1.0 ha to 3.2 ha on flat to moderate terrain over the studied period, while the frequency of harvesting increased from 249 to 495 sites per year. On the steep terrain, 35% of the harvesting was done with cable yarding, and 62% with harvester-forwarder systems. On the very steep terrain (>60% slope), 88% of the area was harvested using cable yarding technology while harvesters and forwarders were used on 12% of the area. Overall, FCL proved to be a useful dataset for the purpose of assessing harvesting activity under the given conditions.
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KRIEGLER, ELMAR, MASSIMO TAVONI, TINO ABOUMAHBOUB, GUNNAR LUDERER, KATHERINE CALVIN, GAUTHIER DEMAERE, VOLKER KREY, et al. "WHAT DOES THE 2°C TARGET IMPLY FOR A GLOBAL CLIMATE AGREEMENT IN 2020? THE LIMITS STUDY ON DURBAN PLATFORM SCENARIOS." Climate Change Economics 04, no. 04 (November 2013): 1340008. http://dx.doi.org/10.1142/s2010007813400083.
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This paper provides a novel and comprehensive model-based assessment of possible outcomes of the Durban Platform negotiations with a focus on emissions reduction requirements, the consistency with the 2°C target and global economic impacts. The Durban Platform scenarios investigated in the LIMITS study — all assuming the implementation of comprehensive global emission reductions after 2020, but assuming different 2020 emission reduction levels as well as different long-term concentration targets — exhibit a probability of exceeding the 2°C limit of 22–41% when reaching 450 (450–480) ppm CO 2 e , and 35–59% when reaching 500 (480–520) ppm CO 2 e in 2100. Forcing and temperature show a peak and decline pattern for both targets. Consistency of the resulting temperature trajectory with the 2°C target is a societal choice, and may be based on the maximum exceedance probability at the time of the peak and the long run exceedance probability, e.g., in the year 2100. The challenges of implementing a long-term target after a period of fragmented near-term climate policy can be significant as reflected in steep reductions of emissions intensity and transitional and long-term economic impacts. In particular, the challenges of adopting the target are significantly higher in 2030 than in 2020, both in terms of required emissions intensity decline rates and economic impacts. We conclude that an agreement on comprehensive emissions reductions to be implemented from 2020 onwards has particular significance for meeting long-term climate policy objectives.
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Ossa-Moreno, Juan, Greg Keir, Neil McIntyre, Michela Cameletti, and Diego Rivera. "Comparison of approaches to interpolating climate observations in steep terrain with low-density gauging networks." Hydrology and Earth System Sciences 23, no. 11 (November 22, 2019): 4763–81. http://dx.doi.org/10.5194/hess-23-4763-2019.
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Abstract. The accuracy of hydrological assessments in mountain regions is often hindered by the low density of gauges coupled with complex spatial variations in climate. Increasingly, spatial datasets (i.e. satellite and other products) and new computational tools are merged with ground observations to address this problem. This paper presents a comparison of approaches of different complexities to spatially interpolate monthly precipitation and daily temperature time series in the upper Aconcagua catchment in central Chile. A generalised linear mixed model (GLMM) whose parameters are estimated through approximate Bayesian inference is compared with simpler alternatives: inverse distance weighting (IDW), lapse rates (LRs), and two methods that analyse the residuals between observations and WorldClim (WC) data or Climate Hazards Group Infrared Precipitation with Station data (CHIRPS). The assessment is based on a leave-one-out cross validation (LOOCV), with the root-mean-squared error (RMSE) being the primary performance criterion for both climate variables, while the probability of detection (POD) and false-alarm ratio (FAR) are also used for precipitation. Results show that for spatial interpolation of temperature and precipitation, the approaches based on the WorldClim or CHIRPS residuals may be recommended as being more accurate, easy to apply and relatively robust to tested reductions in the number of estimation gauges. The GLMM has comparable performance when all gauges were included and is better for estimating occurrence of precipitation but is more sensitive to the reduction in the number of gauges used for estimation, which is a constraint in sparsely monitored catchments.
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Dahle, Emil Aall, and Dag Myrhaug. "Risk Analysis Applied to Capsize of Fishing Vessels." Marine Technology and SNAME News 32, no. 04 (October 1, 1995): 245–47. http://dx.doi.org/10.5957/mt1.1995.32.4.245.
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Although contributing only moderately to the total ship loss rate, capsize provides the dominating human loss rate contribution for the smaller vessel. This is of special concern for fishing vessels because their human loss rate is considered as unacceptable in many countries in the world. In the paper, it is suggested that a risk analysis method be applied to manage the risk of capsize. The analysis is derived in steps. First, dangerous wave events are selected; steep near-breaking waves above certain heights, synchronous waves, and high waves with the same speed as the ship are selected. Next, the frequency of occurrence is calculated based upon published wave statistics and recent research. Then, the vessel's response to the selected wave events has to be found by model tests or by using simple analytical models. Finally, the probability of occurrence of wave/vessel encounters per year that will cause capsize is calculated. Various rational ways of reducing the probability to an acceptable level are presented and discussed, and are illustrated by practical examples for two U.S. fishing areas, one on the West Coast and one on the East Coast. The application of already available information and knowledge is advocated with less emphasis on development of complicated mathematical models.
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Paul, Elliot, Anup Pant, Stephanie George, John Willson, Stacey Meardon, and Ali Vahdati. "In silico modeling of tibial fatigue life in physically active males and females during different exercise protocols." Biomedical Physics & Engineering Express 8, no. 3 (April 8, 2022): 035019. http://dx.doi.org/10.1088/2057-1976/ac62ff.
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Abstract Preventing bone stress injuries (BSI) requires a deep understanding of the condition’s underlying causes and risk factors. Subject-specific computer modeling studies of gait mechanics, including the effect of changes in running speed, stride length, and landing patterns on tibial stress injury formation can provide essential insights into BSI prevention. This study aimed to computationally examine the effect of different exercise protocols on tibial fatigue life in male and female runners during prolonged walking and running at three different speeds. To achieve these aims, we combined subject-specific magnetic resonance imaging (MRI), gait data, finite element analysis, and a fatigue life prediction algorithm, including repair and adaptation’s influence. The algorithm predicted a steep increase in the likelihood of developing a BSI within the first 40 days of activity. In five of the six subjects simulated, faster running speeds corresponded with higher tibial strains and higher probability of failure. Our simulations also showed that female subjects had a higher mean peak probability of failure in all four gait conditions than the male subjects studied. The approach used in this study could lay the groundwork for studies in larger populations and patient-specific clinical tools and decision support systems to reduce BSIs in athletes, military personnel, and other active individuals.
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Hakim Sagitaningrum, Fathiyah, Widjojo Adi Prakoso, and Erly Bahsan. "Probabilistic Analysis of Cut-Slope Stability for Tropical Red Clay of Depok, West Java as an Effect of Rainfall Duration and Intensity." MATEC Web of Conferences 147 (2018): 07004. http://dx.doi.org/10.1051/matecconf/201814707004.
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Landslide in Indonesia, specifically in Java island, occurs during rainy seasons. In Java island, it is known that the tropical red clay has the ability to stand at steep angles, while in stability analysis due to rainfall, practitioners only consider the rise of groundwater table. Previous studies states that one of the factor affecting factor of safety (FS) for tropical red clay slopes is the formation of saturated zones due to matric suction. This research studies the effect of rainfall intensity and duration to FS of cut-slopes as parametric study with probabilistic analysis for different height of 10m, 20m, and 30m also slope angles of 27°, 45°, 55°, and 70°. Rainfall parameter are taken from FTUI rainfall station for advanced pattern and three-days duration of rain. Analysis of seepage uses SEEP/W and slope stability uses SLOPE/W. It is known that the significant increase of probability of failure due to the three-days rainfall is achieved at the 10m height and 70°-angled slope. Increase of the probability of failure is mainly due to rainfall infiltration which saturates the surface and pore water pressure increase until certain time where infiltration stops and turn into surface run-off.
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Pineda, Nicolau, and Oriol Rodríguez. "ERA5 Reanalysis of Environments Conducive to Lightning-Ignited Wildfires in Catalonia." Atmosphere 14, no. 6 (May 26, 2023): 936. http://dx.doi.org/10.3390/atmos14060936.
Full textAbstract:
In the climate change context, wildfires are an increasing hazard in the Mediterranean Basin, especially those triggered by lightning. Although lightning activity can be predicted with a reasonable level of confidence, the challenge remains in forecasting the thunderstorm’s probability of ignition. The present work aims to characterise the most suitable predictors to forecast lightning-ignited wildfires. Several ERA5 parameters were calculated and compared for two different samples, thunderstorm episodes that caused a wildfire (n = 961) and ordinary thunderstorms (n = 1023) that occurred in Catalonia (NE Iberian Peninsula) in the 2006–2020 period. Lightning wildfires are mostly associated with dry thunderstorms, characterised by: weak-to-moderate Mixed-Layer Convective Available Potential Energy (MLCAPE, 150–1100 J kg−1), significant Dew Point Depression at 850 hPa (DPD850, 3.3–10.1 °C), high Most-Unstable Lifted Condensation Level (MULCL, 580–1450 m) and steep 500–700 hPa Lapse Rate (LR, −7.0–−6.3 °C). Under these conditions, with relatively dry air at lower levels, thunderstorms tend to be high-based, the rain evaporating before reaching the ground and lightning occurring without significant rainfall. Specifically forecasting the probability of LIW occurrence would be of great assistance to the forest protection tactical decision-making process, preparing for “dry” thunderstorm days where multiple ignitions can be expected.
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Morris, Paul J., Nachiketa Chakraborty, and Garret Cotter. "Deviations from normal distributions in artificial and real time series: a false positive prescription." Monthly Notices of the Royal Astronomical Society 489, no. 2 (August 16, 2019): 2117–29. http://dx.doi.org/10.1093/mnras/stz2259.
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ABSTRACT Time-series analysis allows for the determination of the Power Spectral Density (PSD) and Probability Density Function (PDF) for astrophysical sources. The former of these illustrates the distribution of power at various time-scales, typically taking a power-law form, while the latter characterizes the distribution of the underlying stochastic physical processes, with Gaussian and lognormal functional forms both physically motivated. In this paper, we use artificial time series generated using the prescription of Timmer & Koenig to investigate connections between the PDF and PSD. PDFs calculated for these artificial light curves are less likely to be well described by a Gaussian functional form for steep (Γ⪆1) PSD indices due to weak non-stationarity. Using the Fermi LAT monthly light curve of the blazar PKS2155-304 as an example, we prescribe and calculate a false positive rate that indicates how likely the PDF is to be attributed an incorrect functional form. Here, we generate large numbers of artificial light curves with intrinsically normally distributed PDFs and with statistical properties consistent with observations. These are used to evaluate the probabilities that either Gaussian or lognormal functional forms better describe the PDF. We use this prescription to show that PKS2155-304 requires a high prior probability of having a normally distributed PDF, $P(\rm {G})~$ ≥ 0.82, for the calculated PDF to prefer a Gaussian functional form over a lognormal. We present possible choices of prior and evaluate the probability that PKS2155-304 has a lognormally distributed PDF for each.