期刊文献+
共找到8,379篇文章
< 1 2 250 >
每页显示 20 50 100
Countability of Infinite Paths in the Infinity Tree: Proof of the Continuum Hypothesis in a Non-Cantorian Infinity Theory
1
作者 Philip C. Jackson 《Advances in Pure Mathematics》 2025年第1期73-90,共18页
A previous paper showed that the real numbers between 0 and 1 could be represented by an infinite tree structure, called the ‘infinity tree’, which contains only a countably infinite number of nodes and arcs. This p... A previous paper showed that the real numbers between 0 and 1 could be represented by an infinite tree structure, called the ‘infinity tree’, which contains only a countably infinite number of nodes and arcs. This paper discusses how a finite-state Turing machine could, in a countably infinite number of state transitions, write all the infinite paths in the infinity tree to a countably infinite tape. Hence it is argued that the real numbers in the interval [0, 1] are countably infinite in a non-Cantorian theory of infinity based on Turing machines using countably infinite space and time. In this theory, Cantor’s Continuum Hypothesis can also be proved. And in this theory, it follows that the power set of the natural numbers P(ℕ) is countably infinite, which contradicts the claim of Cantor’s Theorem for the natural numbers. However, this paper does not claim there is an error in Cantor’s arguments that [0, 1] is uncountably infinite. Rather, this paper considers the situation as a paradox, resulting from different choices about how to represent and count the continuum of real numbers. 展开更多
关键词 INFINITY Countable UNCOUNTABLE Diagonalization Real Numbers Infinity Tree Continuum hypothesis Turing Machine Infinite Time Turing Machine Non-Cantorian
在线阅读 下载PDF
Consequences of Invariant Functions for the Riemann Hypothesis
2
作者 Michael Mark Anthony 《Advances in Pure Mathematics》 2025年第1期36-72,共37页
This paper attempts to form a bridge between a sum of the divisors function and the gamma function, proposing a novel approach that could have significant implications for classical problems in number theory, specific... This paper attempts to form a bridge between a sum of the divisors function and the gamma function, proposing a novel approach that could have significant implications for classical problems in number theory, specifically the Robin inequality and the Riemann hypothesis. The exploration of using invariant properties of these functions to derive insights into twin primes and sequential primes is a potentially innovative concept that deserves careful consideration by the mathematical community. 展开更多
关键词 LambertW Function Principal Branch Riemann hypothesis ITERATIONS Robin Inequality Robin Integers INVARIANCE Gauss Gamma Function Li-Function Prime Counting Function Sums of Divisors INVARIANCE PRIMES Twin Primes
在线阅读 下载PDF
The dilatancy-diffusion hypothesis,earthquake prediction,and operational earthquake forecasting:In memory of Professor Amos Nur on the 50th Anniversary of the 1975 Haicheng Earthquake
3
作者 Lanbo Liu 《Earthquake Science》 2025年第5期465-484,共20页
Dilatancy is referred to the phenomenon of volume increase that occurs when a material is deformed.Dilatancy theory originated in geomechanics for the study of the behavior of granular materials.Later it is expanded t... Dilatancy is referred to the phenomenon of volume increase that occurs when a material is deformed.Dilatancy theory originated in geomechanics for the study of the behavior of granular materials.Later it is expanded to the case of more brittle materials like rocks when it is subjected to the load of varying effective stress and starts to crack and deform,then named the dilatancy-diffusion hypothesis.This hypothesis was developed to explain the changes in rock volume and pore pressure that occur prior to and during fault slip,which can influence earthquake dynamics.Dilatancy-fluid diffusion is a significant concept in understanding the seismogenic process and has served as the major theoretical pillar for earthquake prediction by its classic definition.This paper starts with the recount of fundamental laboratory experiments on granular materials and rocks,then conducts review and examination of the history for using the dilatancy-diffusion hypothesis to interpret the‘prediction’of the 1975 Haicheng Earthquake and other events.The Haicheng Earthquake is the first significant event to be interpreted with the dilatancy-diffusion hypothesis in the world.As one pivotal figure in the development of the dilatancy-diffusion hypothesis for earthquake prediction Professor Amos Nur of Stanford University worked tirelessly to attract societal attention to this important scientific and humanistic issue.As a deterministic physical model the dilatancy-diffusion hypothesis intrinsically bears the deficit to interpret the stochastic seismogenic process.With the emergence of deep learning and its successful applications to many science and technology fields,we may see a possibility to overcome the shortcoming of the current state of the theory with the addition of empirical statistics to push the operational earthquake forecasting approach with the addition of the physicallyinformed neural networks which adopt the dilatancy-diffusion hypothesis as one of its embedded physical relations,to uplift the seismic risk reduction to a new level for saving lives and reducing the losses. 展开更多
关键词 dilatancy-diffusion hypothesis Amos Nur Haicheng Earthquake earthquake prediction operational earthquake forecasting(OEF) physically-informed neural networks(PINNs)
在线阅读 下载PDF
Hygiene hypothesis in inflammatory bowel disease: A criticalreview of the literature 被引量:17
4
作者 Natasha A Koloski Laurel Bret Graham Radford-Smith 《World Journal of Gastroenterology》 SCIE CAS CSCD 2008年第2期165-173,共9页
The hygiene hypothesis is thought to be a significant contributor to the growing incidence of inflammatory bowel disease (IBD) around the world, although the evidence for specific factors that underlie the hygiene hyp... The hygiene hypothesis is thought to be a significant contributor to the growing incidence of inflammatory bowel disease (IBD) around the world, although the evidence for specific factors that underlie the hygiene hypothesis in IBD is unclear. We aimed to systematically review the literature to determine which hygiene-related factors are associated with the development of IBD. Publications identified from a broad based MEDLINE and Current Contents search between 1966 and 2007 on key terms relevant to the 'hygiene hypothesis' and IBD including H pylori exposure, helminths, cold chain hypothesis, measles infection and vaccination, antibiotic use, breastfeeding, family size, sibship, urban upbringing, day care attendance and domestic hygiene were reviewed. The literature suggests that the hygiene hypothesis and its association with decreased microbial exposure in childhood probably plays an important role in the development of IBD, although the strength of the supporting data for each of the factors varies considerably. The most promising factors that may potentially be associated with development of IBD include H pylori exposure, helminths, breastfeeding and sibship. However, the vast majority of studies in this area are plagued by serious methodological shortcomings, particularly the reliance on retrospective recall of information making it difficult to truly ascertain the importance of a 'hygiene hypothesis' in IBD. The 'hygiene hypothesis' in IBD is an important area of research that may give clues to the aetiology of this disease. Directions for future research are recommended. 展开更多
关键词 Inflammatory bowel disease Hygiene hypothesis Microbial exposure Cold chain hypothesis H pylori HELMINTHS MEASLES Antibiotic BREASTFEEDING Child care
暂未订购
The Enlightment on Task-based Teaching Derived from Input Hypothesis 被引量:1
5
作者 周春红 《Sino-US English Teaching》 2006年第4期36-38,43,共4页
Aiming at gradually developing and perfecting the task-based teaching method, the essay, with enlightment from the Krashen's Input Hypothesis, discusses some issues about input, output, activities and teacher's role... Aiming at gradually developing and perfecting the task-based teaching method, the essay, with enlightment from the Krashen's Input Hypothesis, discusses some issues about input, output, activities and teacher's role in this method. 展开更多
关键词 task-based teaching input hypothesis INPUT OUTPUT ACTIVITIES teacher's role
在线阅读 下载PDF
Rules Governing Pressure Distribution for a Traveling Charge Under the Condition of Lagrange Hypothesis
6
作者 罗运军 谭惠民 陈福泰 《Journal of Beijing Institute of Technology》 EI CAS 1999年第2期43-49,共7页
Aim To study the rules governing pressure distribution of traveling charge under the condition of Lagrange hypothesis. Methods\ The study is based on the laws of conservation of momentum and energy. Results\ The gas ... Aim To study the rules governing pressure distribution of traveling charge under the condition of Lagrange hypothesis. Methods\ The study is based on the laws of conservation of momentum and energy. Results\ The gas flow velocity distribution formula at the back of a projectile and the momentum equation of a traveling charge are deduced, and rules governing their pressure distribution under the Lagrange hypothesis conditions are established. The pressure distribution of a traveling charge is compared with that of a conventional charge. Conclusion\ The pressure distribution in the bore of a traveling charge can be accurately predicted. A parabolic pressure distribution type is revealed. 展开更多
关键词 GUN traveling charge interior ballistics pressure distribution Lagrange hypothesis
在线阅读 下载PDF
Riemann Hypothesis, Catholic Information and Potential of Events with New Techniques for Financial and Other Applications
7
作者 Prodromos Char. Papadopoulos 《Advances in Pure Mathematics》 2021年第5期524-572,共49页
In this research we are going to define two new concepts: a) “The Potential of Events” (EP) and b) “The Catholic Information” (CI). The term CI derives from the ancient Greek language and declares all the Catholic... In this research we are going to define two new concepts: a) “The Potential of Events” (EP) and b) “The Catholic Information” (CI). The term CI derives from the ancient Greek language and declares all the Catholic (general) Logical Propositions (<img src="Edit_5f13a4a5-abc6-4bc5-9e4c-4ff981627b2a.png" width="33" height="21" alt="" />) which will true for every element of a set A. We will study the Riemann Hypothesis in two stages: a) By using the EP we will prove that the distribution of events e (even) and o (odd) of Square Free Numbers (SFN) on the axis Ax(N) of naturals is Heads-Tails (H-T) type. b) By using the CI we will explain the way that the distribution of prime numbers can be correlated with the non-trivial zeros of the function ζ(s) of Riemann. The Introduction and the Chapter 2 are necessary for understanding the solution. In the Chapter 3 we will present a simple method of forecasting in many very useful applications (e.g. financial, technological, medical, social, etc) developing a generalization of this new, proven here, theory which we finally apply to the solution of RH. The following Introduction as well the Results with the Discussion at the end shed light about the possibility of the proof of all the above. The article consists of 9 chapters that are numbered by 1, 2, …, 9. 展开更多
关键词 Twin Problem Twin’s Problem Unsolved Mathematical Problems Prime Number Problems Millennium Problems Riemann hypothesis Riemann’s hypothesis Number Theory Information Theory Probabilities Statistics Management Financial Applications Arithmetical Analysis Optimization Theory Stock Exchange Mathematics Approximation Methods Manifolds Economical Mathematics Random Variables Space of Events Strategy Games Probability Density Stock Market Technical Analysis Forecasting
在线阅读 下载PDF
Multi-Angle Exploration on the Inner Relationship among Language,Thought and Culture with “Sapir-Whorf Hypothesis”
8
作者 李芳 《海外英语》 2019年第12期85-86,共2页
“Sapir-Whorf hypothesis"holds that human thoughts are shaped by their native languages,and speakers of different languages think differently relevantly.The hypothesis is controversial partly because it seems to ... “Sapir-Whorf hypothesis"holds that human thoughts are shaped by their native languages,and speakers of different languages think differently relevantly.The hypothesis is controversial partly because it seems to deny the possibility of a general principle for human cognition,and partly because some findings taken to support it have not reliably replicated.The author argued that considering this hypothesis through the lens of probabilistic inference has the potential to figure out both issues,at least with respect to certain prominent findings in the two languages—Chinese and English.After exploring on the inner relationship among language,thought and culture with the comparison between English and Chinese based on a series of examples including“numbers,Wuhan dialect and some different understandings of idioms”,the author made an inference that language can somewhat affect human thought under the different culture contexts.Besides,it also provides some reference for educators to take in-depth studies on the relationship among language,thought and culture,which is vitally significant for ESL educators and learners. 展开更多
关键词 Sapir-Whorf hypothesiS INNER relationship LANGUAGE THOUGHT CULTURE
在线阅读 下载PDF
Sapir-Whorf Hypothesis and Translation
9
作者 姜海清 《海外英语》 2013年第5X期4-6,共3页
Sapir-Whorf hypothesis has its implication in translation studies. Each language is a peculiar whole. It is a product, even an expression, of the spiritual personality and the cultural particularity. Translation is a ... Sapir-Whorf hypothesis has its implication in translation studies. Each language is a peculiar whole. It is a product, even an expression, of the spiritual personality and the cultural particularity. Translation is a kind of interlingual and intercultural communication. It involves not only the transference from one language into another, but a whole set of extra-linguistic criteria. In translating we are always crossing a greater or lesser barrier or divide. 展开更多
关键词 Sapir-Whorf hypothesiS IMPLICATION LINGUISTIC tran
在线阅读 下载PDF
A Critical Review of Critical Period Hypothesis in Second Language Acquisition
10
作者 黄一平 《海外英语》 2011年第7X期296-298,310,共4页
The researches on Critical Period Hypothesis(CPH) aims to explain the importance of the age factor in the process of learning a second language.In this essay,a critical review of the theoretical issues and empirical r... The researches on Critical Period Hypothesis(CPH) aims to explain the importance of the age factor in the process of learning a second language.In this essay,a critical review of the theoretical issues and empirical research on the CPH will spread out.Meanwhile,the discussion of implication and limitation of the CPH research will be concerned as well. 展开更多
关键词 CRITICAL PERIOD hypothesiS SECOND LANGUAGE ACQUISITION age
在线阅读 下载PDF
Thought Confidence: Consumer Emotions and the Confidence Premise Hypothesis
11
作者 Hsuan-Yi Chou 《Management Studies》 2016年第5期219-226,共8页
Thought confidence,a subjective perception of metacognition,and the accompanying self-validated effects that occur when thought confidence is induced after exposure to persuasive messages have recently received increa... Thought confidence,a subjective perception of metacognition,and the accompanying self-validated effects that occur when thought confidence is induced after exposure to persuasive messages have recently received increasing attention from scholars.This construct/mechanism has received little exploration in the past,while there remain important research gaps.One question is whether thought confidence can play different roles when induced at different times;another is whether more variables can be identified which effectively induce confidence in existing or subsequent thoughts.The current paper examines a possible antecedent of thought confidence(i.e.,consumer emotions)and explores the effects of thought confidence induced in consumers before they are exposed to advertisements.The author posited the confidence premise hypothesis,which holds that higher consumer confidence is a prerequisite for the significantly positive effects of argument strength in advertisements.Eighty-one undergraduates participated in a 2(emotions:good moods vs.neutral moods)×2(argument strength:strong arguments vs.weak arguments)between-subjects experiment.Experimental results indicate that consumers'emotions positively affect their confidence in thoughts generated later.There is an anticipated pattern of interaction between emotions and argument strength in affecting advertising effectiveness,which supports the confidence premise hypothesis.The implications of these and other findings are discussed. 展开更多
关键词 thought confidence METACOGNITION self-validated hypothesis consumer emotions confidence premisehypothesis argument strength
在线阅读 下载PDF
A Brief Analysis of Contrastive Analysis Hypothesis
12
作者 佘阿莉 《海外英语》 2017年第24期21-21,共1页
This paper makes a brief analysis on the contrastive analysis hypothesis, and it is hoped to be helpful for the English teachers.
关键词 contrastive analysis hypothesis second language acquisition
在线阅读 下载PDF
Krashen's Input Hypothesis and Its Pedagogical Implications on Second Language Teaching 被引量:3
13
作者 田东旭 李瑶 《海外英语》 2016年第4期201-203,共3页
Krashen has developed the Input Hypothesis, which has deep influence on teaching method of second language. This thesis focuses on the Krashen's Input Hypothesis, which includes the following five hypotheses: the ... Krashen has developed the Input Hypothesis, which has deep influence on teaching method of second language. This thesis focuses on the Krashen's Input Hypothesis, which includes the following five hypotheses: the acquisition- learning hypothesis, the monitor hypothesis, the natural order hypothesis, the input hypothesis and the effective filter hypothesis. The thesis tries to explore the pedagogical implications of Krashen's Input Hypothesis on second language teaching in the aspects of the input quantity and input quality. The thesis tries to explore the most effective methods of second language teaching, in the hope that it will help to improve the efficiency of second language teaching. 展开更多
关键词 KRASHEN INPUT hypothesiS SECOND LANGUAGE TEACHING
在线阅读 下载PDF
Pharmacokinetics of traditional Chinese syndrome and recipe:a hypothesis and its verification(Ⅰ) 被引量:16
14
作者 Xi Huang Ping Ren Ai Dong Wen Li Li Wang Li Zhang Feng Gao Laboratory of Clinical Pharmacology of Chinese Medicine,Xijing Hospital,The Fourth Military Medical University,Xi’an 710032,Shaanxi Province,China Department of Pharmacy,Xijing Hospital,The Fourth Military Medical University,Xi’an 710032,Shaanxi Province,China Department of Physiology,The Fourth Military Medical University,Xi’an 710032,Shaanxi Province,China 《World Journal of Gastroenterology》 SCIE CAS CSCD 2000年第3期384-391,共8页
AIM To propose a hypothesis defining theabsorption,distribution,metabolism andelimination of traditional Chinese recipe(TCR)-component in blood of healthy subjects andpatients,and estimate its correctness.METHODS Th... AIM To propose a hypothesis defining theabsorption,distribution,metabolism andelimination of traditional Chinese recipe(TCR)-component in blood of healthy subjects andpatients,and estimate its correctness.METHODS The pharmacokinetics(PK)of samedose of drug was studied in the animal model oftraditional Chinese syndrome(S)and healthyanimals.The classification,terminology,concept and significance of the hypothesis wereset forth with evidence provided in the presentstudy.The hypotheses consisted of traditionalChinese syndrome PK(S-PK)and traditionalChinese recipe PK(R-PK).Firstly,the observedtetramethylpyrazine(TMP)PK in healthy,chronically reserpinized rats(rat model ofspleen deficiency syndrome,RMSDS)andRMSDS treated with Sijunzi decoction(SJZD)forconfirmation were used to verify S-PK; secondly,the ferulic acid(FA)PK in healthy andhigh molecular weight dextran(HMWD)-inducedrabbit model with blood stasis syndrome(RDBSS)was also used to verify S-PK;andlastly,TMP PK parameters in serum of healthyrats after orally taken Ligusticum wallichii(LW),LW and Salvia miltiorrhiza(LW&SM)decoctions were compared to verify R-PK.RESULTS The apparent first-order absorption[Ka,(13.61±2.56)h<sup>-1</sup>,area under the blooddrug concentration-time curve[AUC,(24.88±9.76)μg.h<sup>-1</sup>mL<sup>-1</sup>],maximum drug concentration[C<sub>max</sub>,(4.82±1.23)μg·mL<sup>-1</sup>]of serum TMP inRMSDS were increased markedly(P【0.05)compared with those[Ka=(5.41±1.91)h<sup>-1</sup>,AUC=(5.20±2.57)μg·h<sup>-1</sup>·mL<sup>-1</sup>,C<sub>max</sub>=(2.33±1.77)μg·mL<sup>-1</sup>]of healthy rats(HR).Theapparent first-order rate constant for α and βdistribution phase[α=(0.38±0.09)h<sup>-1</sup>,β=(0.06±0.03)h<sup>-1</sup>,the apparent first-orderintercompartmental transfer rate constants[K<sub>10</sub>=(0.24±0.07)h<sup>-1</sup>,K<sub>12</sub>=(0.11±0.02)h<sup>-1</sup>,K<sub>21</sub>=(0.11±0.02)h<sup>-1</sup>]of serum TMP in RMSDS weredecreased significantly(P【0.01)comparedwith those[K<sub>10</sub>=(0.88±0.20)h<sup>-1</sup>,K<sub>12</sub>=(1.45±0.47)h<sup>-1</sup>,K<sub>21</sub>=(0.72±0.22)h<sup>-1</sup>]of HR.However,no apparent differences occurredbetween HR and RMSDS treated with SJZD.Theserum FA concentration and its AUC[(5.6690±2.3541)μg·h<sup>-1</sup>·mL<sup>-1</sup>] in RMBSS were also higherthan those[AUC=(2.7566±0.8232)μg·h<sup>-1</sup>·mL<sup>-1</sup>]of healthy rabbits(P【0.05).The Ka(11.51±2.82)h<sup>-1</sup>,AUC(0.84±0.17)μg·h<sup>-1</sup>·mL<sup>-1</sup>of LW & SM-derived TMP in serum weremuch lower(P【0.05)than those[Ka=(19.58±4.14)h<sup>-1</sup>,AUC=(1.27±0.26)μg·h<sup>-1</sup>·mL<sup>-1</sup>]ofLW-derived TMP in serum after oral decoctions.CONCLUSION The SDS and blood stasissyndrome state could affect significantly thepharmacokinetic parameters of drugs and theabnormal SDS pharmacokinetic parameters couldbe normalized by SJZD.The combination ofChinese medicine in TCR could reciprocallyaffect the pharmacokinetic parameters of othercomponents absorbed into the systemiccirculation.These results support the S-and R-PK hypothesis. 展开更多
关键词 TRADITIONAL CHINESE syndrome/recipe CHINESE medicine PHARMACOKINETICS blood stasis spleen deficiency hypothesiS
暂未订购
A measurement-driven adaptive probability hypothesis density filter for multitarget tracking 被引量:9
15
作者 Si Weijian Wang Liwei Qu Zhiyu 《Chinese Journal of Aeronautics》 SCIE EI CAS CSCD 2015年第6期1689-1698,共10页
This paper studies the dynamic estimation problem for multitarget tracking. A novel gat- ing strategy that is based on the measurement likelihood of the target state space is proposed to improve the overall effectiven... This paper studies the dynamic estimation problem for multitarget tracking. A novel gat- ing strategy that is based on the measurement likelihood of the target state space is proposed to improve the overall effectiveness of the probability hypothesis density (PHD) filter. Firstly, a measurement-driven mechanism based on this gating technique is designed to classify the measure- ments. In this mechanism, only the measurements for the existing targets are considered in the update step of the existing targets while the measurements of newborn targets are used for exploring newborn targets. Secondly, the gating strategy enables the development of a heuristic state estima- tion algorithm when sequential Monte Carlo (SMC) implementation of the PHD filter is investi- gated, where the measurements are used to drive the particle clustering within the space gate. The resulting PHD filter can achieve a more robust and accurate estimation of the existing targets by reducing the interference from clutter. Moreover, the target birth intensity can be adaptive to detect newborn targets, which is in accordance with the birth measurements. Simulation results demonstrate the computational efficiency and tracking performance of the proposed algorithm. 展开更多
关键词 ADAPTIVE Measurement-driven Multitarget trackin Probability hypothesis density Sequential Monte Carlo
原文传递
Improved pruning algorithm for Gaussian mixture probability hypothesis density filter 被引量:8
16
作者 NIE Yongfang ZHANG Tao 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2018年第2期229-235,共7页
With the increment of the number of Gaussian components, the computation cost increases in the Gaussian mixture probability hypothesis density(GM-PHD) filter. Based on the theory of Chen et al, we propose an improved ... With the increment of the number of Gaussian components, the computation cost increases in the Gaussian mixture probability hypothesis density(GM-PHD) filter. Based on the theory of Chen et al, we propose an improved pruning algorithm for the GM-PHD filter, which utilizes not only the Gaussian components’ means and covariance, but their weights as a new criterion to improve the estimate accuracy of the conventional pruning algorithm for tracking very closely proximity targets. Moreover, it solves the end-less while-loop problem without the need of a second merging step. Simulation results show that this improved algorithm is easier to implement and more robust than the formal ones. 展开更多
关键词 Gaussian mixture probability hypothesis density(GM-PHD) filter pruning algorithm proximity targets clutter rate
在线阅读 下载PDF
Location of rut stands vs. mating opportunities in Przewalski's gazelle: A field test of the "Resource-based Hypothesis" and "Female Traffic Version of the Hotspot Hypothesis" 被引量:4
17
作者 Zhangqiang YOU Zhigang JIANG Chunwang LI 《Current Zoology》 SCIE CAS CSCD 北大核心 2011年第6期701-708,共8页
We studied the mating tactics of Przewalski's gazelle on the Qinghal-Tibetan Plateau from 2002 to 2005. Przewalski's gazelle is a cluster mating animal whereby female groups, including juveniles, travel to and from ... We studied the mating tactics of Przewalski's gazelle on the Qinghal-Tibetan Plateau from 2002 to 2005. Przewalski's gazelle is a cluster mating animal whereby female groups, including juveniles, travel to and from their resting grounds along fixed routes and dominant males stand on or near these travel routes during rut. To explain rut patterns in male ga- zelles, we tested predictions arising from the "Resource-based Hypothesis" and "Female Traffic Version of the Hotspot Hypothe- sis". We marked the location of each rut stand and female travel route, measured food availability in each rut stand and recorded the mating opportunities of rut stand owners. We also conducted a field experiment to force female groups to change their daily travel route, and observed whether males abandon their original rut stands and shift their rut stands to new travel routes of females during the 3rdrut. We found that: (1) male gazelle defending rut stands closer to a female travel route had a higher chance of mat- ing; (2) food resources within rut stands had no effect on mating opportunities of the rut stand owner; (3) when the female travel route was obstructed, female groups changed grazing sites, and all males abandoned their original rut stands and defended new rut stands along the new female travel route. In conclusion, the location of rut stands in relation to female travel routes is the ultimate factor for consolidating mating opportunities in male gazelle, supporting the "Female Route Version of Hotspot Hypothesis 展开更多
关键词 Procapra przewalskii Rut stand Hotspot hypothesis Mating opportunity Food availability
原文传递
Does pressure cause liver cirrhosis? The sinusoidal pressure hypothesis 被引量:6
18
作者 Sebastian Mueller 《World Journal of Gastroenterology》 SCIE CAS 2016年第48期10482-10501,共20页
Independent of their etiology, all chronic liver diseases ultimately lead to liver cirrhosis, which is a majorhealth problem worldwide. The underlying molecular mechanisms are still poorly understood and no efficient ... Independent of their etiology, all chronic liver diseases ultimately lead to liver cirrhosis, which is a majorhealth problem worldwide. The underlying molecular mechanisms are still poorly understood and no efficient treatment strategies are available. This paper introduces the sinusoidal pressure hypothesis(SPH), which identifies an elevated sinusoidal pressure(SP) as cause of fibrosis. SPH has been mainly derived from recent studies on liver stiffness. So far, pressure changes have been exclusively seen as a consequ-ence of cirrhosis. According to the SPH, however, an elevated SP is the major upstream event that initiates fibrosis via biomechanic signaling by stretching of perisinusoidal cells such as hepatic stellate cells or fibroblasts(SPH part?Ⅰ: initiation). Fibrosis progression is determined by the degree and time of elevated SP. The SPH predicts that the degree of extracellular matrix eventually matches SP with critical thresholds > 12 mmH g and > 4 wk. Elevated arterial flow and final arterialization of the cirrhotic liver represents the self-perpetuating key event exposing the low-pressure-organ to pathologically high pressures(SPH part?Ⅱ: perpetuation). It also defines the "point of no return" where fibrosis progression becomes irreversible. The SPH is able to explain the macroscopic changes of cirrhotic livers and the uniform fibrotic response to various etiologies. It also opens up new views on the role of fat and disease mechanisms in other organs. The novel concept will hopefully stimulate the search for new treatment strategies. 展开更多
关键词 liver stiffness Stretch force Sinusoidal pressure hypothesis liver cirrhosis Hepatic arterial buffer response biomechanics Arterialization Hepatic stellate cells FIBROBLASTS cellular and intercellular mechano-signaling
暂未订购
科学工作假说(Working Hypothesis)是科学创新的基础 被引量:12
19
作者 刘东生 《第四纪研究》 CAS CSCD 北大核心 2006年第5期673-677,共5页
中国第四纪研究委员会成立50年来,第四纪科学已进于一个新的后第四纪研究时代了。显著的特点是研究工作由描述性向理念性,由区域性向全球性,由学科性向系统科学性迈进。在此过程中“科学工作假说”的不断出现,是促进其生长的动力。在195... 中国第四纪研究委员会成立50年来,第四纪科学已进于一个新的后第四纪研究时代了。显著的特点是研究工作由描述性向理念性,由区域性向全球性,由学科性向系统科学性迈进。在此过程中“科学工作假说”的不断出现,是促进其生长的动力。在1950年代对中国黄土成因的许多不同的假说促进了后来中国黄土研究的发展。当前中国第四纪研究的许多关于全球变化问题的科学假说,将开辟一个第四纪研究的新时代。 展开更多
关键词 科学工作假说 科学创新
在线阅读 下载PDF
Probability hypothesis density filter with adaptive parameter estimation for tracking multiple maneuvering targets 被引量:2
20
作者 Yang Jinlong Yang Le +1 位作者 Yuan Yunhao Ge Hongwei 《Chinese Journal of Aeronautics》 SCIE EI CAS CSCD 2016年第6期1740-1748,共9页
The probability hypothesis density(PHD) filter has been recognized as a promising technique for tracking an unknown number of targets. The performance of the PHD filter, however, is sensitive to the available knowledg... The probability hypothesis density(PHD) filter has been recognized as a promising technique for tracking an unknown number of targets. The performance of the PHD filter, however, is sensitive to the available knowledge on model parameters such as the measurement noise variance and those associated with the changes in the maneuvering target trajectories. If these parameters are unknown in advance, the tracking performance may degrade greatly. To address this aspect, this paper proposes to incorporate the adaptive parameter estimation(APE) method in the PHD filter so that the model parameters, which may be static and/or time-varying, can be estimated jointly with target states. The resulting APE-PHD algorithm is implemented using the particle filter(PF), which leads to the PF-APE-PHD filter. Simulations show that the newly proposed algorithm can correctly identify the unknown measurement noise variances, and it is capable of tracking multiple maneuvering targets with abrupt changing parameters in a more robust manner, compared to the multi-model approaches. 展开更多
关键词 Adaptive parameter estimation Multiple target tracking Multivariate Gaussian distribution Particle filter Probability hypothesis density
原文传递
上一页 1 2 250 下一页 到第
使用帮助 返回顶部