scholarly journals Prediction of the Number of Women Population in Medan City 2025 by Using the Leslie Matrix

2021 ◽  
Vol 9 (1) ◽  
pp. 1-9
Author(s):  
Mulyono Mulyono ◽  
Abil Mansyur ◽  
Faridawaty Marpaung
Keyword(s):  
Leslie Matrix

scholarly journals Population projections for all U.S. counties by age, sex, and race controlled to the Shared Socioeconomic Pathways

2018 ◽  
Author(s):  
Mathew Hauer
Keyword(s):  
Census Data ◽  
Age Groups ◽  
The United States ◽  
Population Projections ◽  
Leslie Matrix ◽  
Ex Post ◽  
Ex Post Facto ◽  
Using Data ◽  
And Control ◽  
Cohort Change

Small area and subnational population projections are important for understanding long-term demographic changes. I provide county-level population projections by age, sex, and race in five-year intervals for the period 2015-2100 for all U.S. counties. Using historic U.S. census data in temporally rectified county boundaries and race groups for the period 1990-2015, I calculate cohort-change ratios (CCRs) and cohort-change differences (CCDs) for eighteen five-year age groups (0-85+), two sex groups (Male and Female), and four race groups (White NH, Black NH, Other NH, Hispanic) for all U.S counties. I then project these CCRs/CCDs using ARIMA models as inputs into Leslie matrix population projection models and control the projections to the Shared Socioeconomic Pathways. I validate the methods using ex-post facto evaluations using data from 1969-2000 to project 2000-2015. My results are reasonably accurate for this period. These data have numerous potential uses and can serve as inputs for addressing questions involving sub-national demographic change in the United States.

The Method of Forecasting the Population of Chinese Population Attractive Cities

2013 ◽  
Vol 295-298 ◽  
pp. 2654-2659 ◽  
Author(s):  
Shu Hao Jiao
Keyword(s):  
Chinese Population ◽  
Local Population ◽  
Local Economy ◽  
Floating Population ◽  
Leslie Matrix ◽  
The People ◽  
Population Forecasting ◽  
Long Time ◽  
The City ◽  
Male To Female

This paper presents a method of forecasting the population of Chinese population attractive cities. In this model the overall population is divided into two main parts, floating population(the people who will live in the city for a long time but do not have household register) and local population. The increment of floating population is positively correlated with the increment of local GDP approximately. Leslie matrix is used to imitate the process of the local population growth. Four main factors, death rate, birth rate, the ratio of male to female, and the growth of the local economy are considered to forecast the local population and floating population separately. The method in this paper overcome these shortcomings of the former method that they cannot explain the inner changes of the population, and ignore the factor of migration. So this method will offer a basis for the science of population forecasting.

Analysing persistence of grass swards in terms of tiller birth and death

2011 ◽  
Vol 15 ◽  
pp. 63-68
Author(s):  
C. Matthew ◽  
Sackville Hamilton
Keyword(s):  
Abiotic Stresses ◽  
Birth Rate ◽  
Phleum Pratense ◽  
Leslie Matrix ◽  
Published Data ◽  
Population Stability ◽  
Death Rates ◽  
Timothy Grass ◽  
High Death ◽  
Bud Site

A methodology is developed to analyse the contribution to sward persistence of the processes tiller birth and tiller death, and variation in their rate over an annual cycle. The methodology is tested using previously published data for timothy grass (Phleum pratense). The analysis shows that high death rates of timothy tillers in summer present a problem for persistence in that tiller appearance rates required to maintain the tiller population in these conditions require tiller bud site usage statistics that are biologically unlikely in field swards. While it is not suggested that ryegrass has a naturally high tiller death rate in summer as demonstrated here for timothy, where abiotic stresses reduce ryegrass tiller survival, the same principles are likely to apply. Keywords: Leslie matrix, Phleum pratense, population stability, tiller birth rate, tiller survival rate, timothy grass

Age-structured models in a random environment

2019 ◽  
pp. 194-213
Author(s):  
Louis W. Botsford ◽  
J. Wilson White ◽  
Alan Hastings
Keyword(s):  
Time Series ◽  
Environmental Variability ◽  
Extinction Risk ◽  
Population Viability Analysis ◽  
Leslie Matrix ◽  
Vital Rates ◽  
Viability Analysis ◽  
Practical Concern ◽  
Probability Of Extinction ◽  
Age Structured

Most ecological populations exist in a randomly fluctuating environment, and these fluctuations influence vital rates, thus changing population dynamics. These changes are the focus of this chapter. The primary practical concern about environmental variability is the possibility that it could cause a population to go extinct, so the chapter describes several approaches to estimating the probability of extinction. The first is the small fluctuations approximation (SFA) to describe the growth of a population with a randomly varying Leslie matrix. The results reveal that randomly varying populations grow more slowly on average than the equivalent deterministic population. Further applications of the SFA examine how correlated variation in different vital rates affects the probability of extinction, when variability is too large to use the SFA, and how it has been applied to population time series. Finally, several other approaches to estimating extinction risk—also known as population viability analysis—are compared.

Optimization Problems Associated with a Leslie Matrix

1976 ◽  
Vol 110 (973) ◽  
pp. 339-349 ◽  
Author(s):  
Roy Mendelssohn
Keyword(s):  
Optimization Problems ◽  
Leslie Matrix

Diagnosing declining grassland wader populations using simple matrix models

2009 ◽  
Vol 59 (1) ◽  
pp. 127-144 ◽  
Author(s):  
Lia Hemerik ◽  
Chris Klok ◽  
Maja Roodbergen
Keyword(s):  
Growth Rate ◽  
Population Growth ◽  
Matrix Models ◽  
Population Growth Rate ◽  
Adult Stage ◽  
Demographic Data ◽  
Leslie Matrix ◽  
Adult Survival ◽  
Demographic Parameters ◽  
Survival And Reproduction

AbstractMany populations of wader species have shown a strong decline in number in Western-Europe in recent years. The use of simple population models such as matrix models can contribute to conserve these populations by identifying the most profitable management measures. Parameterization of such models is often hampered by the availability of demographic data (survival and reproduction). In particular, data on survival in the pre-adult (immature) stage of wader species that remain in wintering areas outside Europe are notoriously difficult to obtain, and are therefore virtually absent in the literature. To diagnose population decline in the wader species; Black-tailed Godwit, Curlew, Lapwing, Oystercatcher, and Redshank, we extended an existing modelling framework in which incomplete demographic data can be analysed, developed for species with a pre-adult stage of one year. The framework is based on a Leslie matrix model with three parameters: yearly reproduction (number of fledglings per pair), yearly pre-adult (immature) and yearly adult (mature) survival. The yearly population growth rate of these populations and the relative sensitivity of this rate to changes in survival and reproduction parameters (the elasticity) were calculated numerically and, if possible, analytically. The results showed a decrease in dependence on reproduction and an increase in pre-adult survival of the population growth rate with an increase in the duration of the pre-adult stage. In general, adult survival had the highest elasticity, but elasticity of pre-adult survival increased with time to first reproduction, a result not reported earlier. Model results showed that adult survival and reproduction estimates reported for populations of Redshank and Curlew were too low to maintain viable populations. Based on the elasticity patterns and the scope for increase in actual demographic parameters we inferred that conservation of the Redshank and both Curlew populations should focus on reproduction. For one Oystercatcher and the Black-tailed Godwit populations we suggested a focus on both reproduction and pre-adult survival. For the second Oystercatcher population pre-adult survival seemed the most promising target for conservation. And for the Lapwing populations all demographic parameters should be considered.

scholarly journals Spectral properties of a near-periodic row-stochastic Leslie matrix

2005 ◽  
Vol 409 ◽  
pp. 166-186 ◽  
Author(s):  
Mei-Qin Chen ◽  
Xiezhang Li
Keyword(s):  
Spectral Properties ◽  
Leslie Matrix

scholarly journals THE INFLUENCE OF THE UNIVERSAL TWO-CHILD POLICY ON CHINA’S FUTURE AGING AND POPULATION

2019 ◽  
Vol 3 (Supplement_1) ◽  
pp. S706-S706
Author(s):  
Can Jia ◽  
Handong li
Keyword(s):  
Family Planning ◽  
Rural Areas ◽  
Leslie Matrix ◽  
Chinese Government ◽  
Growth Trend ◽  
Family Planning Policy ◽  
Registration System ◽  
Planning Policy ◽  
Child Policy ◽  
The Impact

Abstract China’s aging situation is becoming more and more prominent, and both the people and the government are facing unprecedented pressure of providing for the aged. For this reason, the Chinese government began implementing a new family planning policy for couples to have two children since 2016 (referred to as “universal two-child policy”). In order to explore the impact of the newly released policy, our research is based on the sixth census of China. And first, we use the cohort-component method and a Leslie matrix to construct the population prediction model. Considering some certain unique factors in China, such as the significant urban-rural dual structure and the household registration system and so on, we divide the total fertility rate into urban and rural areas which fully reflects the characteristics of China’s family planning policy. Then we predict and analyze the number and structure of China population between 2011 and 2050 based on the three scenarios of high, medium and low. And the results show that the Chinese population will present an inverted pyramid structure, and the population structure will continue to deteriorate. Besides, we adapt three indicators to analyze the aging trend in China, namely, the old-age coefficient, the population aging index, and the social dependency ratio. And the three indicators of China will continue to grow under the universal two-child policy with different changing rate, which means, the newly released policy will not change China’s aging population growth trend and the severity of China’s aging.

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