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A hybrid approach for estimating hydro-geomorphological rainfall thresholds to shallow landslides
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作者 Francesco FUSCO 《Journal of Mountain Science》 2025年第11期4072-4092,共21页
The societal risk related to rainfalltriggered rapid debris flows is commonly managed in urbanized areas by means of early warning systems based on monitoring of hydrological parameters(such as rainfall or soil moistu... The societal risk related to rainfalltriggered rapid debris flows is commonly managed in urbanized areas by means of early warning systems based on monitoring of hydrological parameters(such as rainfall or soil moisture) and thresholds values.In Alpine catchments,this type of landslides is recurrent and represent one of the major geohazards.Debris flows are typically initiated by high-intensity rainstorms,prolonged rainfall with moderate intensity or snow melting.They frequently happen in situations of temporary infiltration into soils that are initially unsaturated.During significant rainfall events,the rise in pore water pressure can become crucial for the stability of slopes in particular areas.This phenomenon relies on hydraulic and geotechnical characteristics,along with the thickness of the involved soils.This procedure can result in a local drop in shear strength,as both apparent cohesion and effective stress decline,while driving forces rise because of the increase in unit weight.Accordingly,this study estimates Intensity-Duration(I-D) rainfall thresholds at the site-specific and distributed scales by combining empirical and physics-based approaches and modeling of soil coverings involved in soil slips or debris slides inducing debris flows.The approach was tested for mountain slopes of the Valtellina valley(Lombardia region,northern Italy),which suffered several catastrophic landslide events in the last decades.The empirical approach was adopted to reconstruct physics-based slope models of representative source areas of past debris flows events.To such a scope,nonpunctual but distributed data of hydro-mechanical soil properties and thicknesses were considered.Thus,to reconstruct the unsaturated/saturated critical conditions leading the slope instability,a combined hydrological modeling and infinite-slope stability analysis was adopted.This combined hydromechanical numerical model was used to attempt to determine a three-dimensional Intensity-Duration threshold for landslide initiation considering plausible rainfall for the Valtellina valley.Due to the lack of reliable records of past landslide hindering a thorough empirical analysis,the presented approach can be considered as a feasible approach for establishing a warning standard in urbanized areas at risk of shallow landslides triggered by rainfall.Moreover,findings highlight the importance of having access to spatially distributed soil characteristics to define and enhance input data for physics-based modelling.Finally,the proposed approach can aid an early warning system for the onset of shallow landslides by utilizing real-time rainfall monitoring or now-casting through a meteorological radar technique. 展开更多
关键词 Shallow landslides Debris flow Physics-based approach Rainfall thresholds Three-dimensional thresholds
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Thermal Entanglement in Disordered Spin Chains:Localization,Thresholds,and the Quantum-to-Classical Crossover
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作者 Dihang Sun Zhigang Hu Biao Wu 《Chinese Physics Letters》 2025年第7期150-155,共6页
We investigate the mixed-state entanglement between two spins embedded in the XXZ Heisenberg chain under thermal equilibrium.By deriving an analytical expression for the entanglement of two-spin thermal states and ext... We investigate the mixed-state entanglement between two spins embedded in the XXZ Heisenberg chain under thermal equilibrium.By deriving an analytical expression for the entanglement of two-spin thermal states and extending this analysis to larger spin chains,we demonstrate that mixed-state entanglement is profoundly shaped by both disorder and temperature.Our results reveal a sharp distinction between many-body localized and ergodic phases,with entanglement vanishing above diferent fnite temperature thresholds.Furthermore,by analyzing non-adjacent spins,we uncover an approximate exponential decay of entanglement with separation.This work advances the understanding of the quantum-to-classical transition by linking the entanglement properties of small subsystems to the broader thermal environment,ofering an explanation for the absence of entanglement in macroscopic systems.These fndings provide critical insights into quantum many-body physics,bridging concepts from thermalization,localization,and quantum information theory. 展开更多
关键词 quantum classical crossover LOCALIZATION disordered spin chains thresholds xxz heisenberg chain larger spin chainswe thermal entanglement
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Relationship between Cortical Auditory Evoked Potential (CAEP) Responses and Behavioral Thresholds in Children with Sensorineural Hearing Loss
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作者 Hee Yen Tan Wendi Shi Yonghua Wang 《Journal of Biosciences and Medicines》 2025年第2期480-490,共11页
Objective: To study the relationship between cortical auditory evoked potential (CAEP) thresholds and behavioral thresholds in pediatric populations with sensorineural hearing loss (SNHL). Methods: Fifteen children (m... Objective: To study the relationship between cortical auditory evoked potential (CAEP) thresholds and behavioral thresholds in pediatric populations with sensorineural hearing loss (SNHL). Methods: Fifteen children (mean age 6.8 years) with bilateral SNHL underwent behavioral pure-tone audiometry and CAEP testing at 0.5, 1, 2, and 4 kHz. CAEP thresholds were determined using tone bursts, and correlations between CAEP and pure-tone thresholds were analyzed using Pearson correlation and t-tests. Results: A strong positive correlation was observed between P1 thresholds and behavioral thresholds across all test frequencies: 0.5 kHz (r = 0.765, p Conclusion: The strong correlation between P1 and behavioral thresholds demonstrates the reliability of CAEP testing for estimating auditory thresholds in children. These findings support the use of CAEP testing as a reliable objective tool for threshold estimation, particularly in cases where behavioral responses cannot be reliably obtained. When adjusted with frequency-specific correction values, CAEP testing provides a reliable method for assessing hearing thresholds in pediatric populations. 展开更多
关键词 Cortical Auditory Evoked Potentials Behavioral thresholds Sensorineural Hearing Loss Hearing Threshold Estimation
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Characteristics of stress thresholds of granite after triaxial dynamic impact treatment
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作者 PENG Kang LIU Xu +3 位作者 YIN Xu-yan ZHANG Yun CHANG Yang-kai LUO Song 《Journal of Central South University》 2025年第7期2553-2569,共17页
The geostress and rock blasting in underground engineering may greatly affect the stress thresholds of surrounding rock.In this study,pre-damage impact tests were first conducted on granite under varying confining pre... The geostress and rock blasting in underground engineering may greatly affect the stress thresholds of surrounding rock.In this study,pre-damage impact tests were first conducted on granite under varying confining pressures(5,10 and 15 MPa)and numbers of impacts(1,5,10 and 15 impacts).Then,uniaxial compression tests were undertaken on the pre-damaged granite to study the evolution of stress thresholds using the crack volume strain method and acoustic emission method.The crack damage stresses determined by the two methods were compared.Additionally,based on the rise time amplitude and average frequency,the evolution law of microcracks inside rock specimens was revealed,and an improved acoustic emission method was proposed.The results indicated that as the number of impacts increased,the crack closure stress,crack damage stress,and peak stress of granite specimens initially rose and then declined,while they continuously increased with the confining pressure.The proportion of shear cracks first declined and then rose with greater number of impacts and decreased with higher confining pressure,and that of tensile cracks showed the opposite trend.The improved acoustic emission method was more accurate in identifying the crack damage stress. 展开更多
关键词 stress threshold crack volume strain crack damage stress rock damage acoustic emission
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Effect of minimum and maximum electrical stimulation levels on sound field thresholds,and speech perception in children using the Advanced Bionics Cochlear Implant
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作者 Muthuselvi Thangaraj Ravikumar Arunachalam +1 位作者 Madhuri Gore Ajith Kumar Uppunda 《Journal of Otology》 2025年第3期170-175,共6页
BackgroundIt's crucial to study the effect of changes in thresholds(T)and most comfortable levels(M)on behavioral measurements in young children using cochlear implants.This would help the clinician with the optim... BackgroundIt's crucial to study the effect of changes in thresholds(T)and most comfortable levels(M)on behavioral measurements in young children using cochlear implants.This would help the clinician with the optimization and validation of programming parameters.ObjectiveThe study has attempted to describe the changes in behavioral responses with modification of T and M levels.MethodsTwenty-five participants in the age range 5 to 12 years using HR90K/HiFocus1J or HR90KAdvantage/HiFocus1J with Harmony speech processors participated in the study.A decrease in T levels,a rise in T levels,or a decrease in M levels in the everyday program were used to create experimental programs.Sound field thresholds and speech perception were measured at 50 dBHL for three experimental and everyday programs.ConclusionThe results indicated that only reductions of M levels resulted in significantly(p<0.01)poor aided thresholds and speech perception.On the other hand,variation in T levels did not have significant changes in either sound field thresholds or speech perception.The results highlight that M levels must be correctly established in order to prevent decreased speech perception and audibility. 展开更多
关键词 T levels M levels sound field threshold speech perception
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Effect of the phytohormone salicylic acid on the salinity thresholds to seed germination and seedling growth in the oilseed Camelina sativa
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作者 Esmaeil Bakhshandeh Fatemeh Hosseini Sanehkoori +2 位作者 Najmeh Mirzaaghpour Charlotte E.Seal Mozhgan Alinia 《Oil Crop Science》 2025年第1期1-8,共8页
The oilseed crop Camelina sativa exhibits salinity tolerance,but the effects on early growth stages across a range of different salts and in combination with salicylic acid(SA)have not been thoroughly evaluated.In thi... The oilseed crop Camelina sativa exhibits salinity tolerance,but the effects on early growth stages across a range of different salts and in combination with salicylic acid(SA)have not been thoroughly evaluated.In this study,seeds were germinated in varying concentrations of six salts(NaCl,CaCl_(2),ZnCl_(2),KCl,MgSO_(4),and Na2SO_(4))with or without 0.5 mM SA.Using the halotime model,we estimated salt thresholds for germination and parameters of seedling growth.Germination and seedling growth parameters of camelina significantly decreased with increasing salt concentration across all salt types.Salts containing Zn and SO_(4) were most detrimental to germination and seedling growth.Except for KCl,0.5 mM SA generally reduced the salinity tolerance threshold(Saltb(50))of camelina.Specifically,Saltb(50)was 21.5%higher for KCl and 16.1%,25.0%,54.9%,21.0%,and 5.6%lower for CaCl_(2),NaCl,MgSO_(4),Na2SO_(4),and ZnCl_(2),respectively,when 0.5 mM SA was compared to 0 mM SA.Furthermore,camelina seedling growth was consistently more sensitive than germination across all salt types.SA did not significantly enhance germination or seedling growth and was harmful when combined with certain salts or at the germination stage.It can be concluded that both the type of salt and the concentration of SA are as critical as the salt concentration in saline irrigation water. 展开更多
关键词 Germination percentage Germination rate Seedling growth Salt tolerance threshold value
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Variation of Cd concentration in various rice cultivars and derivation of cadmium toxicity thresholds for paddy soil by species-sensitivity distribution 被引量:42
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作者 SONG Wen-en CHEN Shi-bao +4 位作者 LIU Ji-fang CHEN Li SONG Ning-ning LI Ning LIU Bin 《Journal of Integrative Agriculture》 SCIE CAS CSCD 2015年第9期1845-1854,共10页
It is imperative to derive an appropriate cadmium (Cd) health risk toxicity threshold for paddy soils to ensure the Cd con-centration of rice grains meet the food safety standard. In this study, 20 rice cultivars from... It is imperative to derive an appropriate cadmium (Cd) health risk toxicity threshold for paddy soils to ensure the Cd con-centration of rice grains meet the food safety standard. In this study, 20 rice cultivars from the main rice producing areas in China were selected, and a pot-experiment was conducted to investigate transformation of Cd in paddy soil-rice system with 0 (CK), 0.3 mg kg–1 (T1) and 0.6 mg kg–1 (T2) Cd treatments in greenhouse. The results showed that Cd concentrations of rice grains existed signiifcant difference (P<0.05) in 20 rice cultivars under the same Cd level in soil. The Cd concentrations of rice grains of the CK, T1 and T2 treatments were in the range of 0.143–0.202, 0.128–0.458 and 0.332–0.806 mg kg–1, respectively. Marked differences of the ratios of Cd concentration for soil to rice grain (BCFs) and transfer factors (TFs, root to grain and straw to grain) among the tested cultivars were observed in this study. The bioconcentration factors (BCFgrain) and TFs of the 20 rice cultivars were 0.300–1.112 and 0.342–0.817, respectively. The TFs of Cd from straw to grain ranged from 0.366 to 1.71, with signiifcant differences among these 20 rice cultivars. The bioconcentration factors (BCFgrain) and TFs among the 20 rice cultivars ranged from 0.300–1.112 and 0.342–0.817, respectively. The species-sensitivity distribu-tion (SSD) of Cd sensitivity of the rice species could be iftted wel with Burr-III (R2=0.987) based on the data of BCFs. The toxicity threshold of Cd derived from SSD for the paddy soil was 0.507 mg kg–1 in the present study. 展开更多
关键词 cadmium rice cultivars bioconcentration factor species-sensitivity distribution toxicity thresholds
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Penile sensory thresholds in subtypes of premature ejaculation: implications of comorbid erectile dysfunction 被引量:12
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作者 Xiang Chen Fei-Xiang Wang +2 位作者 Chao HU Nian-Qin Yang Ji-Can Dai 《Asian Journal of Andrology》 SCIE CAS CSCD 2018年第4期330-335,共6页
Penile hypersensitivity plays an important role in premature ejaculation (PE), but differences in penile sensitivity among subtypes of PE are unknown. Therefore, we compared penile sensory thresholds in PE subtypes ... Penile hypersensitivity plays an important role in premature ejaculation (PE), but differences in penile sensitivity among subtypes of PE are unknown. Therefore, we compared penile sensory thresholds in PE subtypes of lifelong and acquired PE, PE with and without erectile dysfunction (ED), PE with an intravaginal ejaculation latency time 〈1 min and 〉1 min, and PE with and without orgasmic pleasure perceptual dysfunction. During August 2014 to January 2016, 136 patients with PE were included. Penile warm, cold, and vibratory thresholds were measured. Data of clinical characteristics, sexual life, Premature Ejaculation Diagnostic Tool (PEDT) score, and the 5-item version of the International Index of Erectile Function (IIEF-5) score were collected. Vibratory thresholds of the PE with ED group were higher in the right coronal sulcus (median amplitude: 4.92 vs 3.65 μm, P= 0.02) and the right penile shaft (median amplitude: 3.87 vs 3.30 μm, P = 0.03), while differences in penile sensory thresholds between other subtypes were not significant. The median PEDT score was lower in the PE without ED group (12 vs 14, P 〈 0.001). The IIEF-5 and PEDT scores were negatively correlated (r = -0.29, P 〈 0.001). Patients with orgasmic pleasure perceptual dysfunction had a lower median IIEF-5 score (20 vs 21, P = 0.02). Patients with PE and ED had lower penile sensitivity, and ED was associated with more severe symptoms and weaker orgasmic pleasure perception. In men with PE, management of comorbid ED is necessary. In case of side effects in erectile function, topical anesthetics should be cautiously used in men with PE and ED. 展开更多
关键词 CLASSIFICATION erectile dysfunction penile sensitivity PENIS premature ejaculation sensory thresholds
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New Algorithm for CBR-RBR Fusion with Robust Thresholds 被引量:14
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作者 XU Mad YU Haiyan SHEN Jiang 《Chinese Journal of Mechanical Engineering》 SCIE EI CAS CSCD 2012年第6期1255-1263,共9页
The case-based reasoning(CBR) and rule-based reasoning(RBR) fusion systems include a diverse range of fusion methods and their tasks are characterized by interleaving combination of the reasoning procedures. Exist... The case-based reasoning(CBR) and rule-based reasoning(RBR) fusion systems include a diverse range of fusion methods and their tasks are characterized by interleaving combination of the reasoning procedures. Existing approaches cannot clarify the complex relationships between data from the knowledge sources nor uniformly represent the heterogeneous case and rule knowledge in one fusion space. As a result, existing approaches fail to solve system fragility due to knowledge uncertainty and reasoning unreliability. For the purpose of addressing the difficulties, a novel algorithm for CBR-RBR fusion with robust thresholds(CRFRT) is proposed. Heterogeneous case and rule knowledge are uniformly represented in one defined fusion unitary space. The robust thresholds have been achieved to distinguish the complex relationships between meta-knowledge in the fusion space and to enhance system capacity of knowledge identification. Furthermore, fusion reasoning strategies are constructed for CRFRT and its procedure based on which robust solution of the fusion reasoning problem is obtained. Finally, CRFRT is validated by benchmark problems in machine learning. Compared with other CBR and RBR approaches, the reasoning efficiency and accuracy are increased by 5% and 2.2% respectively. The variations of system accuracy are decreased by 2% to 3.8%. The above results show that the CRFRT algorithm boosts the system's effectiveness and robustness. The proposed CRFRT can solve the fragility of complex intelligence decision system and give quality performance for fault diagnosis. 展开更多
关键词 case-based reasoning (CBR) rule-based reasoning (RBR) robust thresholds fusion reasoning system (FRS)
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Probabilistic rainfall thresholds in Chibo, India: estimation and validation using monitoring system 被引量:2
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作者 Abhirup DIKSHIT Neelima SATYAM 《Journal of Mountain Science》 SCIE CSCD 2019年第4期870-883,共14页
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 ... 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. 展开更多
关键词 EARLY WARNING PROBABILISTIC thresholds Kalimpong MONITORING
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Estimation of rainfall thresholds for shallow landslides in the Sierra Madre Oriental, northeastern Mexico 被引量:2
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作者 Jorge A.Salinas-Jasso Fernando Velasco-Tapia +2 位作者 Ignacio Navarro de León Ricardo A.Salinas-Jasso Efraín Alva-Nino 《Journal of Mountain Science》 SCIE CSCD 2020年第7期1565-1580,共16页
Landslides induced by prolonged rainfalls are frequent mass movements along the northeastern portion of the Sierra Madre Oriental in Mexico,causing significant damage to infrastructure.In this work,we have studied the... Landslides induced by prolonged rainfalls are frequent mass movements along the northeastern portion of the Sierra Madre Oriental in Mexico,causing significant damage to infrastructure.In this work,we have studied the connection between rainfall and landslides in the Santa Rosa Canyon,a catchment located in the northeastern Mexico.A landslide database triggered by major storms and hurricanes that have hit the region over the past 30 years was analyzed.A total of 92 rainfall events in the Santa Rosa Canyon were studied to determine the amount of precipitation needed to trigger shallow landslides.For each event the duration(D,in hours)and the cumulated rainfall event(E,in mm)were determined by using historical rainfall data from weather stations located near the study area.We have proposed an ED threshold for rainfall-induced landslides with durations 0.5<D<120 hours to address the conditions that trigger these events in the study area.On analyzing the obtained threshold,it has been established that almost 60 mm of a daily rainfall accumulation is required to trigger shallow landslides in the study area.This estimation is consistent with other calculations made for areas close to the Santa Rosa Canyon.Finally,we validated the predictive capability of the threshold with a different set of rainfall data that did not result in landslides performing a straightforward receiver operating characteristic analysis.A good approach was obtained,especially for rainfall events with daily measurements.Results could be used as input information in the design of a landslide early warning system for the northeastern Mexico,and replicated for other landslide prone areas in the region. 展开更多
关键词 Shallow landslides Cumulated rainfall Rainfall thresholds Northeastern Mexico Early warning systems.
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A multiobjective evolutionary optimization method based critical rainfall thresholds for debris flows initiation 被引量:2
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作者 YAN Yan ZHANG Yu +4 位作者 HU Wang GUO Xiao-jun MA Chao WANG Zi-ang ZHANG Qun 《Journal of Mountain Science》 SCIE CSCD 2020年第8期1860-1873,共14页
At present,most researches on the critical rainfall threshold of debris flow initiation use a linear model obtained through regression.With relatively weak fault tolerance,this method not only ignores nonlinear effect... At present,most researches on the critical rainfall threshold of debris flow initiation use a linear model obtained through regression.With relatively weak fault tolerance,this method not only ignores nonlinear effects but also is susceptible to singular noise samples,which makes it difficult to characterize the true quantization relationship of the rainfall threshold.Besides,the early warning threshold determined by statistical parameters is susceptible to negative samples(samples where no debris flow has occurred),which leads to uncertainty in the reliability of the early warning results by the regression curve.To overcome the above limitations,this study develops a data-driven multiobjective evolutionary optimization method that combines an artificial neural network(ANN)and a multiobjective evolutionary optimization implemented by particle swarm optimization(PSO).Firstly,the Pareto optimality method is used to represent the nonlinear and conflicting critical thresholds for the rainfall intensity I and the rainfall duration D.An ANN is used to construct a dual-target(dual-task)predictive surrogate model,and then a PSO-based multiobjective evolutionary optimization algorithm is applied to train the ANN and stochastically search the trained ANN for obtaining the Pareto front of the I-D surrogate prediction model,which is intended to overcome the limitations of the existing linear regression-based threshold methods.Finally,a double early warning curve model that can effectively control the false alarm rate and negative alarm rate of hazard warnings are proposed based on the decision space and target space maps.This study provides theoretical guidance for the early warning and forecasting of debris flows and has strong applicability. 展开更多
关键词 Debris flow Critical rainfall thresholds Multiobjective evolutionary optimization Artificial neural network Pareto optimality
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Behavioral and neural auditory thresholds in a frog 被引量:1
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作者 Ryan C.TAYLOR Karin AKRE +1 位作者 Walter WILCZYNSKI Michael J.RYAN 《Current Zoology》 SCIE CAS CSCD 2019年第3期333-341,共9页
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 ... 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 midbrain.We 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. 展开更多
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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Optimized energy thresholds in a spectral computed tomography scan for contrast agent imaging 被引量:1
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作者 Kai-Xin Huang Zhi Deng +1 位作者 Xiao-Fei Xu Yu-Xiang Xing 《Nuclear Science and Techniques》 SCIE CAS CSCD 2019年第3期15-27,共13页
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 carefu... 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. 展开更多
关键词 SPECTRAL CT CONTRAST AGENT IMAGING Cramer-Rao LOWER BOUND thresholds optimization Kedge
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Context Dependent Auditory Thresholds Determined by Brainstem Audiometry and Prepulse Inhibition in Mongolian Gerbils 被引量:2
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作者 Markus Walter Konstantin Tziridis +1 位作者 Sonke Ahlf Holger Schulze 《Open Journal of Acoustics》 2012年第1期34-49,共16页
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 frequ... 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. 展开更多
关键词 Acoustic TRAUMA HEARING thresholds AUDITORY Processing STARTLE Response
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Probabilistic Rainfall Thresholds for Landslide Episodes in the Sierra Norte De Puebla, Mexico 被引量:1
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作者 Alejandra González Ernesto Caetano 《Natural Resources》 2017年第3期254-267,共14页
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 value... 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. 展开更多
关键词 Processes of Mass Removal thresholds Probability BAYESIAN Method Sierra NORTE DE PUEBLA
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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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作者 曹银真 《Chinese Geographical Science》 SCIE CSCD 1991年第3期68-77,共10页
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... 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 change.It 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 respectively.The changing trend in the past and the 展开更多
关键词 ALLUVIAL FAN Huanghe RIVER DELTA thresholds Breach and CHANGING COURSE
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Impairment of extra-high frequency auditory thresholds in subjects with elevated levels of fasting blood glucose
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作者 Anindya Das Ahmed Faisal Sumit +3 位作者 Nazmul Ahsan Masashi Kato Nobutaka Ohgami Anwarul Azim Akhand 《Journal of Otology》 CSCD 2018年第1期29-35,共7页
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... 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 dB.respectively. The auditory thresholds of the subjects with elevated FBG were significantly(p < 0.05) higher than the control subjects at all the above frequencies, although hearing impairment was most evidently observed at an extra-high(12 kHz) frequency. Subjects with a long duration of diabetes(>10 years) showed significantly(p < 0.05) higher level of auditory 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. 展开更多
关键词 FASTING blood glucose HEARING IMPAIRMENT AUDITORY thresholds Extra-high FREQUENCY
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Effects of heterogeneous adoption thresholds on contact-limited social contagions
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作者 Dan-Dan Zhao Wang-Xin Peng +1 位作者 Hao Peng Wei Wang 《Chinese Physics B》 SCIE EI CAS CSCD 2022年第6期790-800,共11页
Limited contact capacity and heterogeneous adoption thresholds have been proven to be two essential characteristics of individuals in natural complex social systems,and their impacts on social contagions exhibit compl... Limited contact capacity and heterogeneous adoption thresholds have been proven to be two essential characteristics of individuals in natural complex social systems,and their impacts on social contagions exhibit complex nature.With this in mind,a heterogeneous contact-limited threshold model is proposed,which adopts one of four threshold distributions,namely Gaussian distribution,log-normal distribution,exponential distribution and power-law distribution.The heterogeneous edge-based compartmental theory is developed for theoretical analysis,and the calculation methods of the final adoption size and outbreak threshold are given theoretically.Many numerical simulations are performed on the Erdös-Renyi and scale-free networks to study the impact of different forms of the threshold distribution on hierarchical spreading´process,the final adoption size,the outbreak threshold and the phase transition in contact-limited propagation networks.We find that the spreading process of social contagions is divided into three distinct stages.Moreover,different threshold distributions cause different spreading processes,especially for some threshold distributions,there is a change from a discontinuous first-order phase transition to a continuous second-order phase transition.Further,we find that changing the standard deviation of different threshold distributions will cause the final adoption size and outbreak threshold to change,and finally tend to be stable with the increase of standard deviation. 展开更多
关键词 social contagions threshold distribution heterogeneous adoption thresholds limited contact
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Ecological thresholds of phytoplankton community across environmental gradients in the harmful algal blooms-frequently-occurring,subtropical coastal waters,East China Sea
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作者 Ran Ye Chunying Ge +6 位作者 Qiong Wang Qing Xu Guofeng Xu Yongkang Yan Mingli Qin Yanhong Cai Yuejun Fei 《Acta Oceanologica Sinica》 SCIE CAS CSCD 2021年第6期100-110,共11页
Phytoplankton communities can response immediately and directly to environmental changes,and thus have been applied as reliable biotic indicators in aquatic systems.This study provided insights into the relationships ... Phytoplankton communities can response immediately and directly to environmental changes,and thus have been applied as reliable biotic indicators in aquatic systems.This study provided insights into the relationships concerning ecological thresholds of phytoplankton communities and individual taxon in response to environmental changes in coastal waters of northern Zhejiang Province,East China Sea.Results demonstrated that there existed seasonal variations of phytoplankton community ecological thresholds of which spring being higher than those in summer.As for individual species,Prorocentrum donghaiense and Noctiluca scintillans were identified as the most tolerant and sensitive indicator species in spring and summer,respectively.They exhibited strong indications in response to environmental changes.These findings highlighted that phytoplankton community structure in this region was stable when environmental gradients were below the thresholds of sensitive species,whereas potential harmful algal blooms may occur when environmental gradients exceeded the thresholds of tolerant species. 展开更多
关键词 ecological thresholds phytoplankton community environmental gradients indicator species coastal waters of northern Zhejiang Province
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