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Maternal Age, Low Birth Weight and Early Neonatal Death in Tertiary Hospital in the Volta Region of Ghana 被引量:1
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作者 Innocent Afeke Lennox Mac-Ankrah +7 位作者 Ibrahim Jamfaru Kokou H. Amegan-Aho Hintermann Kobina Mbroh Sylvester Y. Lokpo Edem Obum Delali Geni Joseph Adu-Amankwaah Verner N. Orish 《Open Journal of Pediatrics》 2017年第4期254-262,共9页
Objectives: Current study sought to determine an association between Low Birth Weight (LBW) and early neonatal mortality at a resource limited country’s referral hospital and to determine relationship between materna... Objectives: Current study sought to determine an association between Low Birth Weight (LBW) and early neonatal mortality at a resource limited country’s referral hospital and to determine relationship between maternal age and birth outcomes. Method: A retrospective study analyzing data on births in the Volta Regional Hospital, Ghana from the period of November 2011 to June 2016. A total of 8279 births were analyzed. Results: Results suggest that teenage mothers (8.60%) are more likely to give birth to pre-term babies than the elderly (6.60%) and the adult mothers (4.61%). LBW is highest among the teenage mothers (12.69%) followed by the elderly mothers (7.87%) and then the least among the adult mothers (6.48%). Extremely Low Birth Weight (ELBW) and Macrosomia births were more observed among the elderly mothers (0.90%;2.17%) than the teenage (0.28%;0.14%) and adult mothers (0.34%;1.61%) respectively. Data suggest that 100% of the ELBW were pre-term birth, 88.28% Very Low Birth Weight (VLBW), 34.56% LBW and only 1.06% of the pre-term birth were with Normal Birth Weight (NBW). Death rate ranges from 50% for ELBW, 33.59% for VLBW, 8.22% for LBW, 5.43% for Macrosomia and 1.5% for NBW. However, death rate distribution among the various age groups was statistically not significant (P 0.106). Conclusions: Our study suggests that early neonatal death, especially deaths among ELBW and VLBW is still high at the VRH of Ghana and therefore there is the need for further studies into interventions to reduce death among neonates born with VLBW and ELBW. 展开更多
关键词 Low birth Weight NEONATE Early NEONATAL death MATERNAL Age
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Finite family trees of continuous time birth and death processes for evaluating the transmitting speed of information on communication networks
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作者 马驰 王汉兴 《Journal of Shanghai University(English Edition)》 CAS 2007年第3期237-240,共4页
A finite random graph generated by continuous time birth and death processes with exponentially distributed waiting times was investigated, which is similar to a communication network in daily life. The vertices are t... A finite random graph generated by continuous time birth and death processes with exponentially distributed waiting times was investigated, which is similar to a communication network in daily life. The vertices are the living particles, and directed edges go from mothers to daughters. The size of the communication network was studied. Furthermore, the probability of successfully connecting senders with receivers and the transmitting speed of information were obtained. 展开更多
关键词 birth and death processes family tree random graph communication networks
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The Effect of Human Immunodeficiency Virus-1 Infection on Low Birth Weight, Mother to Child HIV Transmission and Infants’ Death in African Area
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作者 Traoré Youssouf Téguété Ibrahima +8 位作者 Dicko Fatoumata Traoré Bocoum Amadou Fané Seydou Traoré Tidiani Traoré Mamadou Salia Dao Seydou Touré Moustapha Varol Nesrin Dolo Amadou 《Open Journal of Obstetrics and Gynecology》 2019年第2期158-169,共12页
Background: It is yet a controversy subject whether low birth weight and infant death are associated to human immunodeficiency virus-1 infection. Objective: To appreciate association between low birth weights, mother ... Background: It is yet a controversy subject whether low birth weight and infant death are associated to human immunodeficiency virus-1 infection. Objective: To appreciate association between low birth weights, mother to child HIV transmission and infant mortality in HIV-1 infected pregnant women delivering between 2011 and 2016. Materials: We conducted 6 years cohort study in urban Mali. Outcome included preterm delivery, small for gestational age, infant survival status and HIV transmission. Comparison concerned women clinical WHO stage, mother viro-immunological status, and newborn anthropometric parameters. Results: HIV-1 infected women who delivered low birth weight newborn were 20.9% (111/531) versus 16.5% (1910/11.546) in HIV negative patients (p = 0.016). CD4 T cell counts low than 350 T cells count were strongly associated to LBW (p = 0.000;RR = 3.03;95% CI [1.89 - 3.16]). There is no significant association between ART that was initiated during pregnancy (p = 0.061, RR = 0.02;CI 95% (1.02 - 1.99)) or during delivery (p = 0.571;RR = 1.01;CI 95% (0.10 - 3.02)) and LBW delivery. In multivariate analysis ART regimens containing protease inhibitor (PI) were lone regimens associated with LBW ((p = 0.030;RR = 1.001;95% confidence interval [1.28 - 3.80]). Very low birth weight was statistically associated to women HIV infection (adjusted relative risk, 2.02;p = 0.000;95% confidence interval (2.17 - 4.10)). There is no significant difference between mother to child HIV transmission rate in the two HIV-infected pregnant women (10 infected children in group 2: MTCT rate 4.5%) and 3 infected children in group 1 (MTCT rate: 2.7%) (p = 0.56;RR, 0.59;CI 95% (0.18 - 4.39)). In multivariate analysis, LBW was associated with infant death (p = 0.001;RR = 2.04;CI 95% [1.04 - 5.05]). The median weight of infant at the moment of death in group 1 was 851 g (IQR: 520 - 1833 g). Significant relationship was found between infant death among LBW newborn with mother WHO stage 2 (p = 0.004;adjusted RR = 3.22;CI 95% [2.25 - 6.00]), CD4 T cells count 3 (p = 0.005;RR = 2.81;CI 95% [1.20 - 4.11]), PI regimens (p = 0.030;RR = 1.00;CI 95% [1.28 - 3.80]). Conclusion: We confirm increased risk of low birth weight and mother HIV-1 infection and we identified strongest association between mortality in infant born to HIV-1 infected mother and LBW. 展开更多
关键词 Low birth Weight Human IMMUNODEFICIENCY Virus INFECTION MOtheR to CHILD Transmission Newborn death MALI
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THE ERGODICITY FOR BI-IMMIGRATION BIRTH AND DEATH PROCESSES IN RANDOM ENVIRONMENT 被引量:1
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作者 胡迪鹤 张书林 《Acta Mathematica Scientia》 SCIE CSCD 2008年第1期43-53,共11页
The concepts of bi-immigration birth and death density matrix in random environment and bi-immigration birth and death process in random environment are introduced. For any bi-immigration birth and death matrix in ran... The concepts of bi-immigration birth and death density matrix in random environment and bi-immigration birth and death process in random environment are introduced. For any bi-immigration birth and death matrix in random environment Q(θ) with birth rate λ 〈 death rate μ, the following results are proved, (1) there is an unique q-process in random environment, P^-(θ*(0);t) = (p^-(θ^*(0);t,i,j),i,j ≥ 0), which is ergodic, that is, lim t→∞(θ^*(0);t,i,j) = π^-(θ^*(0);j) ≥0 does not depend on i ≥ 0 and ∑j≥0π (θ*(0);j) = 1, (2) there is a bi-immigration birth and death process in random enjvironment (X^* = {X^*,t ≥ 0},ε^* = {εt,t ∈ (-∞, ∞)}) with random transition matrix P^-(θ^* (0);t) such that X^* is a strictly stationary process. 展开更多
关键词 Density matrix in random environment random transition matrix Markov process in random environment bi-immigration birth and death density matrix in random environment bi-immigration birth and death process in random environment
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Degree distribution of random birth-and-death network with network size decline 被引量:1
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作者 张晓军 杨会兰 《Chinese Physics B》 SCIE EI CAS CSCD 2016年第6期71-77,共7页
In this paper,we provide a general method to obtain the exact solutions of the degree distributions for random birthand-death network(RBDN) with network size decline.First,by stochastic process rules,the steady stat... In this paper,we provide a general method to obtain the exact solutions of the degree distributions for random birthand-death network(RBDN) with network size decline.First,by stochastic process rules,the steady state transformation equations and steady state degree distribution equations are given in the case of m ≥ 3 and 0 〈 p 〈 1/2,then the average degree of network with n nodes is introduced to calculate the degree distributions.Specifically,taking m = 3 for example,we explain the detailed solving process,in which computer simulation is used to verify our degree distribution solutions.In addition,the tail characteristics of the degree distribution are discussed.Our findings suggest that the degree distributions will exhibit Poisson tail property for the declining RBDN. 展开更多
关键词 random birth-and-death network(RBDN) Markov chain generating function degree distribution
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The Wartime Bridge Reliability Evaluation Model Based on Birth-and-Death Process 被引量:2
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作者 Duo-dian Wang Guo-qing Qiu 《American Journal of Computational Mathematics》 2011年第4期281-284,共4页
At first, the concept of bridge reliability is given, followed with its mathematic model. Then, based on the analysis about the mechanism of the damage and repair of bridges, and the state diversion of bridge network,... At first, the concept of bridge reliability is given, followed with its mathematic model. Then, based on the analysis about the mechanism of the damage and repair of bridges, and the state diversion of bridge network, the state diversion process is proved to be birth-and-death process. In the end, the state diversion balance equation of bridge network is built, and the evaluation model of wartime bridge reliability is got. The model is used in a certain example, and it is proved to be precise and credible. 展开更多
关键词 WARTIME BRIDGE RELIABILITY Evaluation birth-and-death PROCESS
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Kinetics of aggregation growth with competition between catalyzed birth and catalyzed death
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作者 王海锋 林振权 高艳 《Chinese Physics B》 SCIE EI CAS CSCD 2008年第4期1490-1500,共11页
An aggregation growth model of three species A, B and C with the competition between catalyzed birth and catalyzed death is proposed. Irreversible aggregation occurs between any two aggregates of the like species with... An aggregation growth model of three species A, B and C with the competition between catalyzed birth and catalyzed death is proposed. Irreversible aggregation occurs between any two aggregates of the like species with theconstant rate kernels In(n = 1,2, 3). Meanwhile, a monomer birth of an A species aggregate of size k occurs under the catalysis of a B species aggregate of size j with the catalyzed birth rate kernel K(k, j) = Kkj^v, and a monomer death of an A species aggregate of size k occurs under the catalysis of a C species aggregate of size j with the catalyzed death rate kernel L(k, j) = Lkj^v, whcre v is a parameter reflecting the dependence of the catalysis reaction rates of birth and death on the size of catalyst aggregate. The kinetic evolution behaviours of the three species are investigated by the rate equation approach based on the mean-field theory. The form of the aggregate size distribution of A species ak (t) is found to be dependent crucially on the competition between the catalyzed birth and death of A species, as well as the irreversible aggregation processes of the three species: (i) In the v 〈 0 case, the irreversible aggregation dominates the process, and ak(t) satisfies the conventional scaling form; (2) In the v ≥ 0 casc, the competition between the catalyzed birth and death dominates the process. When the catalyzed birth controls the process, ak(t) takes the conventional or generalized scaling form. While the catalyzed death controls the process, the scaling description of the aggregate size distribution breaks down completely. 展开更多
关键词 kinetic scaling behaviour aggregation growth catalyzed birth and death rate equation
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Kinetics of Infection-Driven Growth Model with Birth and Death
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作者 YANG Shun-You ZHU Sheng-Qing KE Jian-Hong LIN Zhen-Quan 《Communications in Theoretical Physics》 SCIE CAS CSCD 2008年第9期787-792,共6页
We propose a two-species infection model, in which an infected aggregate can gain one monomer from a healthy one due to infection when they meet together. Moreover, both the healthy and infected aggregates may lose on... We propose a two-species infection model, in which an infected aggregate can gain one monomer from a healthy one due to infection when they meet together. Moreover, both the healthy and infected aggregates may lose one monomer because of self-death, but a healthy aggregate can spontaneously yield a new monomer. Consider a simple system in which the birth/death rates are directly proportional to the aggregate size, namely, the birth and death rates of the healthy aggregate of size k are J1 k and J2k while the self-death rate of the infected aggregate of size k is J3k. We then investigate the kinetics of such a system by means of rate equation approach. For the J1 〉 J2 case, the aggregate size distribution of either species approaches the generalized scaling form and the typical size of either species increases wavily at large times. For the J1 = J2 case, the size distribution of healthy aggregates approaches the generalized scaling form while that of infected aggregates satisfies the modified scaling form. For the J1 〈 J2 case, the size distribution of healthy aggregates satisfies the modified scaling form, but that of infected aggregates does not scale. 展开更多
关键词 kinetic behavior INFECTION birth/death scaling law
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Sudden birth versus sudden death of entanglement for the extended Werner-like state in a dissipative environment
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作者 单传家 陈涛 +4 位作者 刘继兵 程维文 刘堂昆 黄燕霞 李宏 《Chinese Physics B》 SCIE EI CAS CSCD 2010年第6期39-45,共7页
In this paper, we investigate the dynamical behaviour of entanglement in terms of concurrence in a bipartite system subjected to an external magnetic field under the action of dissipative environments in the extended ... In this paper, we investigate the dynamical behaviour of entanglement in terms of concurrence in a bipartite system subjected to an external magnetic field under the action of dissipative environments in the extended Werner-like initial state. The interesting phenomenon of entanglement sudden death as well as sudden birth appears during the evolution process. We analyse in detail the effect of the purity of the initial entangled state of two qubits via Heisenberg XY interaction on the apparition time of entanglement sudden death and entanglement sudden birth. Furthermore, the conditions on the conversion of entanglement sudden death and entanglement sudden birth can be generalized when the initial entangled state is not pure. In particular, a critical purity of the initial mixed entangled state exists, above which entanglement sudden birth vanishes while entanglement sudden death appears. It is also noticed that stable entanglement, which is independent of different initial states of the qubits (pure or mixed state), occurs even in the presence of decoherence. These results arising from the combination of the extended Werner-like initial state and dissipative environments suggest an approach to control and enhance the entanglement even after purity induced sudden birth, death and revival. 展开更多
关键词 entanglement sudden death birth). extended Werner-like state stable entanglement
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Risk factors of clinical birth asphyxia and subsequent newborn death following nuchal cord in a low-resource setting
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作者 Pascal Foumane Gustave Nkomom +3 位作者 Emile Telesphore Mboudou Julius Dohbit Sama Séraphin Nguefack Boniface Moifo 《Open Journal of Obstetrics and Gynecology》 2013年第9期642-647,共6页
Introduction: Our aim was to identify the risk factors of clinical birth asphyxia and subsequent newborn death in the presence of nuchal cord in a sub-Saharan Africa setting. Methodology: It was a six-months’ case-co... Introduction: Our aim was to identify the risk factors of clinical birth asphyxia and subsequent newborn death in the presence of nuchal cord in a sub-Saharan Africa setting. Methodology: It was a six-months’ case-control study involving 117 parturients whose babies presented with a nuchal cord at delivery. The study was carried out at the Yaoundé Gyneco-Obstetric and Pediatric Hospital, Cameroon, from January 1st to June 30th 2013. Results: The risk factors of clinical birth asphyxia identified were: first delivery, absence of obstetrical ultrasound during pregnancy, nuchal cord with more than one loop, duration of second stage of labor more than 30 minutes during vaginal delivery. The risk factors for newborn death from clinical birth asphyxia in the presence of nuchal cord were: maternal age Conclusion: We recommend a systematic obstetrical ultrasound before labor, so as to detect the presence of a nuchal cord, its tightness and the number of loops. Also, cesarean section should be considered when a nuchal cord is associated with first delivery, tightness or multiple looping. 展开更多
关键词 Risk Factors NUCHAL Cord ADVERSE Outcome birth ASPHYXIA NEWBORN death APGAR Score Cameroon
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Cosmogenic 26Al/10Be Burial Dating of the Birth of the Present Hanjiang River 被引量:1
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作者 XU Xinghua LU Chengqiu +3 位作者 LU Yiming TU Hua WANG Shejiang SUN Xuefeng 《Acta Geologica Sinica(English Edition)》 SCIE CAS CSCD 2020年第1期214-215,共2页
Objective Structural lows and major rift systems provide the basis for the creation of large rivers.The uplift of the Qinling and Daba Mountains structural belts and Tibetan Plateau would have provided the basis for t... Objective Structural lows and major rift systems provide the basis for the creation of large rivers.The uplift of the Qinling and Daba Mountains structural belts and Tibetan Plateau would have provided the basis for the origin and northwest–southeast flow of the ancient Hanjiang River(Lu et al.,2018).After a long-term evolution,the present pattern of Hanjiang River has been formed.Five to six river terraces in the Hanzhong and Yunxian basins along the flanks of Hanjiang River valleys had been identified and some terraces had been dated by using optically stimulated luminescence(OSL),paleomagnetic,and electron spin resonance(ESR)dating methods,and correlating the pedostratigraphy and magnetic susceptibility with the Luochuan loess section by our team(Sun et al.,2016,2017).These terraces are composed of fluvial deposits overlaid with eolian deposits,and record the evolution history of the Hanjiang River.(Fig.1).This study is aimed to deduce the birth time of the present Hanjiang River by using 26Al/10Be burial dating method to date the highest fluvial terraces of the Hanjiang River. 展开更多
关键词 Be BURIAL DATING of the birth of the PRESENT Hanjiang RIVER COSMOGENIC
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Modeling in SolidWorks and analysis of temperature and thermal stress during construction of intake tower 被引量:3
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作者 Hong-yang ZHANG Tong-chun LI Zong-kun LI 《Water Science and Engineering》 EI CAS 2009年第1期95-102,共8页
With a focus on the intake tower of the Yanshan Reservoir, this paper discusses the method of modeling in the 3D CAD software SolidWorks and the interface processing between SolidWorks and the ANSYS code, which decrea... With a focus on the intake tower of the Yanshan Reservoir, this paper discusses the method of modeling in the 3D CAD software SolidWorks and the interface processing between SolidWorks and the ANSYS code, which decreases the difficulty in modeling complicated models in ANSYS. In view of the function of the birth-death element and secondary development with APDL (ANSYS parametric design language), a simulation analysis of the temperature field and thermal stress during the construction period of the intake tower was conveniently conducted. The results show that the temperature rise is about 29.934 ℃ over 3 or 4 days. The temperature differences between any two points are less than 24 ℃. The thermal stress increases with the temperature difference and reaches its maximum of 1.68 MPa at the interface between two concrete layers. 展开更多
关键词 SOLIDWORKS ANSYS APDL birth-death element temperature field thermal stress
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A General Repairable Spare Part Demand Model Based on Quasi Birth and Death Process 被引量:2
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作者 HUANG Zhuo LIANG Liang GUO Bo 《自动化学报》 EI CSCD 北大核心 2006年第2期200-206,共7页
This paper aims at two problems which exist in most of repairable spare part demand models at present: the exponential distribution as the basic assumption and one typical distribution corresponding to a model. A gene... This paper aims at two problems which exist in most of repairable spare part demand models at present: the exponential distribution as the basic assumption and one typical distribution corresponding to a model. A general repairable spare part demand model built on quasi birth-and-death process is developed. This model assumes that both the operational time of the unit and the maintenance time of the unit follow the continuous time phase type distributions. The first passage time distribution to be out of spares, the first mean time to be out of spares, and an algorithm to get the minimal amount of spares under certain restrictions are obtained. At the end of this paper, a numerical example is given. 展开更多
关键词 可靠性 需求模型 死亡过程 指数分布
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An SIRS Epidemic Model with Pulse Vaccination, Birth Pulse and Logistic Death Rate
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作者 GAO JIAN-ZHONG ZHANG TAI-LEI 《Communications in Mathematical Research》 CSCD 2019年第3期247-263,共17页
In this paper, we propose an SIRS epidemic model with pulse vaccination, birth pulse and Logistic death rate. By using the stroboscopic map of a discrete dynamical system, the disease-free periodic solution (DFPS for ... In this paper, we propose an SIRS epidemic model with pulse vaccination, birth pulse and Logistic death rate. By using the stroboscopic map of a discrete dynamical system, the disease-free periodic solution (DFPS for short) of the model under pulse vaccination and birth pulse is obtained. Based on the Floquet theory and comparison theorem of impulsive differential equations, the global asymptotic stability of the DFPS is given, and sufficient conditions for the permanence of the model are obtained. In addition, numerical simulations are done to confirm our theoretical results. 展开更多
关键词 LOGISTIC death rate birth PULSE THRESHOLD value global stability PERMANENCE
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Time of Conception and Birth-Relation of “Big Killers” Patients and Longevity
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作者 Eliyahu Stoupel Abdonas Tamoshiunas +7 位作者 Richardas Radishauskas Gailute Bernotiene Abid Assali Hanna Vaknin Igal Teplitzki Ran Kornowski Evgeny Abramson Eyal Fenig 《Health》 2014年第21期3062-3066,共5页
In recent years some interrelationships between time of birth and longevity were published. Concomitant publications appeared demonstrating links between Space Weather and the timing of medical events;in part of both ... In recent years some interrelationships between time of birth and longevity were published. Concomitant publications appeared demonstrating links between Space Weather and the timing of medical events;in part of both these studies it was shown that Space Weather indices are stronger connected with the time of conception as with the birth time. The aim of these study was to consider birth and conception month of patients suffering from a number of “big killer” pathologies, affecting human longevity and comparing with published data on centenarians—100 - 112 years old persons in the USA. Patients and Methods: We included monthly births distribution of our four papers including patients with Acute Myocardial Infarction undergoing Percutaneous Coronary Intervention (PCI)—n-3765, and admitted in another tertiary medical facility for AMI—n-22,047, and, also patients suffering Rapid—n-1239 and Sudden Cardiac Death—n-327 and, also, patients with oncologic malignancies—n-44587. At all in this group 71,965 patients were included. Their birth and conception months were compared with analogical data of 1574 people of 100 - 112 years old using data of L.A. and N.S. Gavrilov for USA centenarians. Results: The birth months of the cardiovascular and oncology patients were maximal in January, March and April (above 10% at each of these months);their conception was maximal in April, June and July. The monthly distribution of conception and birth of the studied population is presented in Tables 1-3. The maximal birth months of the centenarians were November, September, and October;the maximal conception months were December, January, and February. Conclusion: People suffering Myocardial Infarction, Sudden Cardiac Death and Oncologic Malignancies are in higher numbers born in the first four months of the year and conception in April, June and July. The maximal birth months of the very old people were November, September and October and conception were December, January and February. 展开更多
关键词 CONCEPTION birth Month Acute Myocardial Infarction Rapid SUDDEN Cardiac death CENTENARIANS Solar GEOMAGNETIC Cosmic Ray Activity
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Scaling in Rate-Changeable Birth and Death Processes with Random Removals
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作者 KE Jian-Hong LIN Zhen-Quan CHEN Xiao-Shuang 《Communications in Theoretical Physics》 SCIE CAS CSCD 2009年第1期165-169,共5页
We propose a monomer birth-death model with random removals, in which an aggregate of size k can produce a new monomer at a time-dependent rate I(t)k or lose one monomer at a rate J(t)k, and with a probability P(... We propose a monomer birth-death model with random removals, in which an aggregate of size k can produce a new monomer at a time-dependent rate I(t)k or lose one monomer at a rate J(t)k, and with a probability P(t) an aggregate of any size is randomly removed. We then anedytically investigate the kinetic evolution of the model by means of the rate equation. The results show that the scaling behavior of the aggregate size distribution is dependent crucially on the net birth rate I(t) - J(t) as well as the birth rate I(t). The aggregate size distribution can approach a standard or modified scaling form in some cases, but it may take a scale-free form in other cases. Moreover, the species can survive finally only if either I(t) - J(t) ≥ P(t) or [J(t) + P(t) - I(t)]t ≈ 0 at t ≥ 1; otherwise, it will become extinct. 展开更多
关键词 kinetic behavior birth/death rate changeable scaling law
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A Stochastic SIVS Epidemic Model Based on Birth and Death Process
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作者 Lin Zhu Tiansi Zhang 《Journal of Applied Mathematics and Physics》 2016年第9期1837-1848,共12页
A new stochastic epidemic model, that is, a general continuous time birth and death chain model, is formulated based on a deterministic model including vaccination. We use continuous time Markov chain to construct the... A new stochastic epidemic model, that is, a general continuous time birth and death chain model, is formulated based on a deterministic model including vaccination. We use continuous time Markov chain to construct the birth and death process. Through the Kolmogorov forward equation and the theory of moment generating function, the corresponding population expectations are studied. The theoretical result of the stochastic model and deterministic version is also given. Finally, numerical simulations are carried out to substantiate the theoretical results of random walk. 展开更多
关键词 Epidemic Model VACCINATION Continuous Time Markov Chain birth and death Process Stochastic Differential Equations
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The Determinants of Population Growth in Rwanda
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作者 Daniel Ruturwa Sebikabu Ignace H.Kabano 《Journal of Economic Science Research》 2019年第3期37-44,共8页
The fertility occupies a central position in the study of population growth.The growth of the population depends entirely on human fertility,including birth,death rates and life expectancy.Growth of the fertility is o... The fertility occupies a central position in the study of population growth.The growth of the population depends entirely on human fertility,including birth,death rates and life expectancy.Growth of the fertility is one of the key determinants of the Population Growth.This paper focused on the determinant factors of population growth in Rwanda.From the findings,there is a statistically significance of fertility trends at 0.05 percent because the t-statistic in table-4 is greater than its critical value(1.96)at 0.05 percent.The results provides evidence of Fertility,birth,death and life expectancy as factors which boost population to grow in Rwanda.The results founded,indicate the existence of high fertility rates even decreasing,lead to increase population due to its positive values over time.This means that Fertility rates in Rwanda has a positive impact on the country's population growth,especially in the youth who realizes around 48 percent of entire Rwandan’s Population.The relationship between fertility rate and the time describe a decreasing function,which interesting for us showing that fertility has been reduced over time.In other words,as well as the years increased,the fertility decreased.The coefficient of Time is(-0.117035)which implies that a unit change in time will change Total Fertility Rate(TFR)by(-0.117035),table-1.The model of fertility represents a decreasing function while the time function still increasing,as shows in the figure-2.The fertility variable has positive relationships with the population dependent variable even the fertility coefficient is negative,the probability p-value is significant at 0.05 significance level on one hand and the absolute t-statistic is great than the critical value at 0.05 level of significance,which confirm the statistically significance of t-statistic.The coefficients on the death rate and Life expectancy are respectively positive and significant at all confidence level,table-5. 展开更多
关键词 POPULATION FERTILITY birth death LIFE EXPECTANCY Rwanda
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A Linear Immigration-Birth-Death Model and Its Statistical Inference
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作者 ZHANG Shu-lin WEI Zheng-hong BI Qiu-xiang 《Chinese Quarterly Journal of Mathematics》 CSCD 2014年第3期356-362,共7页
formula of simulation proccss by In this paper, we employ monmnt generating function to obtain some exact transition probability of inlmigration-birth-death(IBD) model and discuss the of sample path and statistical ... formula of simulation proccss by In this paper, we employ monmnt generating function to obtain some exact transition probability of inlmigration-birth-death(IBD) model and discuss the of sample path and statistical inference with complete observations of the IBD the exact transition density formula. 展开更多
关键词 immigration-birth-death process transition density moment generating function maximum likelihood estimator
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Method for Measuring Residual Stresses Induced by Boring in Internal Surface of Tube and Its Validation with XRD Method 被引量:13
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作者 孟龙晖 何宁 +2 位作者 杨吟飞 赵威 戎斌 《Transactions of Nanjing University of Aeronautics and Astronautics》 EI 2014年第5期508-514,共7页
Residual stresses can have a strong effect on the usability of machined parts,and the X-ray diffraction(XRD)measuring equipment,which is commonly used to measure residual stresses,is very expensive.This paper presents... Residual stresses can have a strong effect on the usability of machined parts,and the X-ray diffraction(XRD)measuring equipment,which is commonly used to measure residual stresses,is very expensive.This paper presents a method of measuring the residual stresses induced by boring in the internal surface of a tube with much cheaper equipment.The method,called the strain-based method is mainly based on the strains measured on the external surface of the tube.It is proposed on the basis of the very long tube assumption.The finite element method(FEM)analysis is thus used to validate the length of the tube.Guided by the FEM results,an appropriate length of the tube is chosen,and the residual stresses are obtained from both the strain-based method and the XRD method.Stress profiles obtained from both two methods are compared.The comparison result indicates that the profiles of the two methods agree well with each other.Therefore,it can be concluded that the accuracy of the strain-based method is high enough,and it can be applied to residual stress measurement in practice. 展开更多
关键词 residual stress finite element method(FEM) strain element birth and death X-ray diffraction (XRD)
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