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Probabilistic rainfall thresholds in Chibo, India: estimation and validation using monitoring system

Journal of Mountain Science 2019年第4期16卷 870-883页

作者： Abhirup DIKSHIT Neelima SATYAM Discipline of Civil Engineering Indian Institute of Technology Indore Simrol

The Himalayan region has been severely affected by landslides especially during the monsoons. In particular, Kalimpong region in Darjeeling Himalayas has recorded several landslides and has caused significant loss of life, property and agricultural land. The study region, Chibo has experienced several landslides in the past which were mainly debris and earth slide. Globally, several types of rainfall thresholds have been used to determine rainfall-induced landslide incidents. In this paper, probabilistic thresholds have been defined as it would provide a better understanding compared to deterministic thresholds which provide binary results, i.e., either landslide or no landslide for a particular rainfall event. Not much research has been carried out towards validation of rainfall thresholds using an effective and robust monitoring system. The thresholds are then validated using a reliable system utilizing Microelectromechanical Systems(MEMS) tilt sensor and volumetric water content sensor installed in the region. The system measures the tilt of the instrument which is installed at shallow depths and is ideal for an early warning system for shallow landslides. The change in observed tilt angles due to rainfall would give an understanding of the applicability of the probabilistic model. The probabilities determined using Bayes' theorem have been calculated using the rainfall parameters and landslide data in 2010-2016. The rainfall values were collected from an automatic rain gauge setup near the Chibo region. The probabilities were validated using the MEMS based monitoring system setup in Chibo for the monsoon season of 2017. This is the first attempt to determine probabilities and validate it with a robust and effective monitoring system in Darjeeling Himalayas. This study would help in developing an early warning system for regions where the installation of monitoring systems may not be feasible.

关键词： Early warning Probabilistic thresholds Kalimpong Monitoring

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Optimized energy thresholds in a spectral computed tomography scan for contrast agent imaging

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Nuclear Science and Techniques 2019年第3期30卷 15-27页

作者： Kai-Xin Huang Zhi Deng Xiao-Fei Xu Yu-Xiang Xing Department of Engineering Physics Tsinghua University Key Laboratory of Particle and Radiation Imaging Ministry of Education Tsinghua University

Spectral computed tomography(CT) based on photon counting detectors(PCDs) is a well-researched topic in the field of X-ray imaging. When PCD is applied in a spectral CT system, the PCD energy thresholds must be carefully selected, especially for K-edge imaging, which is an important spectral CT application. This paper presents a threshold selection method that yields better-quality images in K-edge imaging. The main idea is to optimize the energy thresholds ray-by-ray according to the targeted component coefficients, followed by obtaining an overall optimal energy threshold by frequency voting. A low-dose pre-scan is used in practical implementations to estimate the line integrals of the component coefficients for the basis functions. The variance of the decomposed component coefficients is then minimized using the Cramer–Rao lower bound method with respect to the energy thresholds. The optimal energy thresholds are then used to take a full scan and gain better image reconstruction with less noise than would be given by a full scan using the non-optimal energy thresholds. Simulations and practical experiments on imaging iodine and gadolinium solutions, which are commonly used as contrast agents in medical applications, were used to validate the method. The noise was significantly reduced with the same dose relative to the non-optimal energy thresholds in both simulations and in practical experiments.

关键词： Spectral CT Contrast agent imaging Cramer-Rao lower bound thresholds optimization Kedge

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Behavioral and neural auditory thresholds in a frog

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Current Zoology 2019年第3期65卷 333-341页

作者： Ryan C.TAYLOR Karin AKRE Walter WILCZYNSKI Michael J.RYAN Department of Integrative Biology University of Texas at Austin Austin TX USA Department of Biological Sciences Salisbury University Salisbury MD USA Smithsonian Tropical Research Institute Balboa Republic of Panama Neuroscience Institute and Center for Behavioral Neuroscience Georgia State University Atlanta GA USA

Vocalizations play a critical role in mate recognition and mate choice in a number of taxa, especially, but not limited to, orthopterans, frogs, and birds. But receivers can only recognize and prefer sounds that they can hear. Thus a fundamental question linking neurobiology and sexual selection asks-what is the threshold for detecting acoustic sexual displays? In this study, we use 3 methods to assess such thresholds in tdngara frogs: behavioral responses, auditory brainstem responsesz and multi unit electrophysiological recordi ngs from the *** show that thresholds are lowest for multiunit recordings (ca. 45 dB SPL), and then for behavioral responses (ca. 61 dB SPL), with auditory brainstem responses exhibiting the highest thresholds (ca. 71 dB SPL). We discuss why these estimates differ and why, as with other studies, it is unlikely that they should be the same. Although all of these studies estimate thresholds they are not measuring the same thresholds;behavioral thresholds are based on signal salienee whereas the 2 neural assays estimate physiological thresholds. All 3 estimates, however, make it clear that to have an appreciation for detection and salienee of acoustic signals we must listen to those signals through the ears of the receivers.

关键词： anurans auditory brainstem responses auditory thresholds mate choice Physalaemus pustulosus signal recog nition thresholds sexual selection tungara frogs vocalizations

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Impairment of extra-high frequency auditory thresholds in subjects with elevated levels of fasting blood glucose

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Journal of Otology 2018年第1期13卷 29-35页

作者： Anindya Das Ahmed Faisal Sumit Nazmul Ahsan Masashi Kato Nobutaka Ohgami Anwarul Azim Akhand Department of Genetic Engineering and Biotechnology University of Dhaka Dhaka Bangladesh BRAC James P Grant School of Public Health BRAC University Dhaka Bangladesh Department of Occupational and Environmental Health Nagoya University Graduate School of Medicine Nagoya Japan

This study was performed to assess whether there is an association between elevated Fasting Blood Glucose(FBG) and hearing impairment in Bangladeshi population. A total of 142 subjects(72 with elevated FBG; 70 control) were included in the study. The mean auditory thresholds of the control subjects at 1,4,8 and 12 kHz frequencies were 6.35 ± 0.35,10.07 ± 0.91,27.57 ± 1.82, 51.28 ± 3.01 dB SPL(decibel sound pressure level), respectively and that of the subjects with elevated FBG were 8.33 ± 0.66,14.37 ± 1.14, 38.96 土 2.23, and 71.11 ± 2.96 ***. The auditory thresholds of the subjects with elevated FBG were significantly(p 10 years) showed significantly(p thresholds at 8 and 12 kHz, but not at 1 and 4 kHz frequencies,compared to subjects with shorter duration of diabetes(≤10 years). In addition, based on the data of odds ratio, more acute impairment of hearing at the extra-high frequency was observed in diabetic subjects of both older(>40 years) and younger(<40 years) age groups compared to the respective controls. The binary logistic regression analysis showed a 5.79-fold increase in the odds of extra-high frequency hearing impairment in diabetic subjects after adjustment for age, gender and BMI. This study provides conclusive evidence that auditory threshold at an extra-high frequency could be a sensitive marker for hearing impairment in diabetic subjects.

关键词： Fasting blood glucose Hearing impairment Auditory thresholds Extra-high frequency

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A STUDY ON thresholds IN THE CHANGE OF ALLUVIAL FAN AND DELTA OF THE HUANGHE RIVER, CHINA

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Chinese Geographical Science 1991年第3期1卷 68-77页

作者：曹银真

In the river systems, the environmental change always undergoes a process from quantitative to qualitative change. The upper limit of the qualitative change is called threshold. When the process reaches or goes beyond the limit, the original event series will be replaced by the other event series. Investigations show that the evolution of the Huanghe River alluvial fan and delta has also under gone a process from quantitative to qualitative change. The geometric forms in each process are roughly the same. This threshold of the geometric forms not only provides us a quantitative index for plotting the periodicity of the alluvial fan and delta, but also is of importance for estimation of the trend of natural environmental *** is shown that there are three periodic alluvial fans of the Huanghe River since the middle Holocene and four periodic delta since 1855 A.D., the thresholds of their geometric forms are from 0.93 to 0.94 and from 1.2 to 1.21 *** changing trend in the past and the

关键词： alluvial fan Huanghe River delta thresholds Breach and Changing Course

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A Model to Estimate the Impact of thresholds and Caps on Coverage Levels in Community-Based Health Insurance Schemes in Low-Income Countries

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Health 2014年第9期6卷 822-835页

作者： Erika Binnendijk Ruth Koren David M. Dror Felsenstein Medical Research Center Sackler Faculty of Medicine Tel Aviv University Tel Aviv Israel Institute of Health Policy and Management Erasmus University Rotterdam Rotterdam The Netherlands Micro Insurance Academy New Delhi India

Background: Community-based health insurance (CBHI) schemes are increasingly implemented in low-income settings. These schemes limit the coverage they offer both by the types of care considered, and by applying thresholds and/or caps to costs reimbursed. The consequences of these thresholds and/or caps on insurance coverage have hitherto been usually ignored, for lack of data on the distributions of healthcare costs or understanding of their impact on effective coverage levels. This article describes a theoretical model to obtain the distributions even without data collection in the field, and demonstrates the quantitative impact of thresholds and/or caps on claim reimbursements. Methods: This model applies to applications on healthcare expenditures in low-income settings, following research methods examined in the Western world. We looked at hospitalizations and tests;we compared the simulated distributions to empirical data obtained through 11 household surveys conducted between 2008 and 2010 in rural locations (9 in India and 2 in Nepal). Results: We found that the shape of the distributions was very similar in all locations for both benefits, and could be represented by a model based on a lognormal distribution. The agreement between theoretical and empirical results was satisfactory (mostly within 10% difference). Conclusions: The model makes it possible to simulate the expected performance of the CBHI (represented by the percentage of costs or bills covered). The aim is to match costs with local levels of willingness-to-pay for health insurance. This model makes it possible to determine at the stage of package-design the optimal levels of thresholds and/or caps for each benefit-type included.

关键词： Distributions Healthcare Costs Community-Based Health Insurance Micro Health Insurance thresholds Caps

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Probabilistic Rainfall thresholds for Landslide Episodes in the Sierra Norte De Puebla, Mexico

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Natural Resources 2017年第3期8卷 254-267页

作者： Alejandra González Ernesto Caetano Institute of Geography National Autonomous University of Mexico Mexico City Mexico

The Sierra Norte de Puebla, Mexico, has a record of hundreds of mass removal processes triggered by rainfall, where the intensity and duration of the rain are the main mechanisms. In order to determine threshold values for precipitation as a cause of a landslide, the prior, marginal and conditional probabilities were calculated. A Bayesian method was used for one-dimensional (precipitation intensity) and two-dimensional (precipitation intensity and duration) analysis. This suggested a high probability of mass movement when the precipitation exceeds 60 mm within ten days. A proposed warning system is based on classes in which the threshold is exceeded.

关键词： Processes of Mass Removal thresholds Probability Bayesian Method Sierra Norte De Puebla

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Context Dependent Auditory thresholds Determined by Brainstem Audiometry and Prepulse Inhibition in Mongolian Gerbils

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Open Journal of Acoustics 2012年第1期2卷 34-49页

作者： Markus Walter Konstantin Tziridis Sonke Ahlf Holger Schulze Experimental Otolaryngology University of Erlangen-Nuremberg Erlangen Germany

Information on hearing thresholds is not always reliable as differences in these thresholds have been described even for the same species. This may partially be due to different methods used by different labs. A frequently used approach to obtain an estimate of hearing threshold is the electrophysiological recording of auditory brainstem responses (ABR). They are usually recorded under deep anesthesia and represent the auditory evoked far-field potentials at various levels in the central auditory pathway. Alternatively, several behavioral approaches are employed. These commonly use operant or classical conditioning to determine hearing thresholds. A potential disadvantage of these methods is that any sound conditioning may in principle alter auditory perception and therefore auditory thresholds. To exclude this type of methodological bias a prepulse inhibition (PPI) paradigm can be used where an audiogram can be determined without any kind of pre-training. Here we compare the threshold estimates obtained by two different ABR and PPI measurements where stimuli are presented in different contexts, either randomly or non-randomly, to test for a possible effect of auditory sensitization. In addition we test the effect of a frequency specific acoustic trauma on the audiograms obtained with both methods. In general we find behaviorally determined audiograms to be significantly lower in absolute thresh- old compared to ABR measurements. Furthermore non-randomized presentation context of the stimuli generally results in audiograms with 10 to 15 dB lower thresholds than pseudo-randomized presentation. Finally, the amount of threshold loss induced by acoustic trauma is similar for all methods tested.

关键词： Acoustic Trauma Hearing thresholds Auditory Processing Startle Response

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Threshold of climate extremes that impact vegetation productivity over the Tibetan Plateau

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Science China Earth Sciences 2024年第6期67卷 1967-1977页

作者： Zhenggang PIAO Xiangyi LI Hao XU Kai WANG Shuchang TANG Fei KAN Songbai HONG College of Urban and Environmental Sciences Peking UniversityBeijing 100871China

Vegetation growth is adversely impacted by multiple climate extremes related to the water and thermal stress over the Tibetan Plateau(TP).However,it remains unknown at which stress level these climate extremes can trigger the abrupt shifts of vegetation response to climate extremes and result in the maximum vegetation response across *** fill this knowledge gap,we combined the hydrometeorological data and the satellite-derived vegetation index to detect two critical thresholds that determine the response of vegetation productivity to droughts,high-temperature extremes,and low-temperature extremes,respectively,during *** results show that the response of vegetation productivity to droughts rapidly increases once crossing -1.41±0.6 standard deviation(σ)below the normal conditions of soil *** crossing-2.98σ±0.9σ,vegetation productivity is maximum damaged by ***-temperature extremes,which have the two thresholds of 1.34σ±0.4σand 2.31σ±0.4σover TP,are suggested to trigger the strong response of vegetation productivity at a milder stress level than low-temperature extremes(two thresholds:-1.44σ±0.5σand-2.53σ±0.8σ).Moreover,we found the compounded effects of soil moisture deficit in reducing the threshold values of both high-and low-temperature *** on the derived thresholds of climate extremes that impact vegetation productivity,Earth System Models project that southwestern TP and part of the northeastern TP will become the hotspots with a high exposure risk to climate extremes by *** study deciphers the high-impact extreme climates using two important thresholds across TP,which advances the understanding of the vegetation response to different climate extremes and provides a paradigm for assessing the impacts of climate extremes on regional ecosystems.

关键词： Tibetan Plateau Climate extremes thresholds Vegetation productivity

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Genotype and task influence stinging response thresholds of honeybee (<i>Apis mellifera</i>L.) workers of African and European descent

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Open Journal of Ecology 2013年第4期3卷 279-283页

作者： Jose L. Uribe-Rubio Tatiana Petukhova Ernesto Guzman-Novoa CENIDFA-INIFAP Animal Physiology Research Center Ajuchitlán Mexico Department of Statistics University of Guelph Guelph Canada School of Environmental Sciences University of Guelph Guelph Canada

The stinging response thresholds of individual European and Africanized worker honeybees (Apis mellifera L.) were analyzed. Workers of each genotype performing defense (guard and soldier bees) and non-defense (nest and forager bees) associated tasks were collected and exposed to an electric stimulus of 0.5 mA, and the time they took to sting a leather substrate was recorded. Africanized bees had significant lower thresholds of response than European bees. Guards and soldiers were faster to sting than nest and forager bees for the Africanized genotype, whereas for the European genotype, guards stung significantly faster than bees of the other three task groups. This is the first study that shows that individual bees specialized in two defensive tasks also have a lower response threshold for stinging. Our results fit a model of division of labor based on differences in response thresholds to stimuli among workers of different genotypes and task groups.

关键词： Apis mellifera Africanized Honeybees Genotypic Effects Defensive Behavior Response thresholds Division of Labor

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