Demography and Population

Demography and Population tài liệu, giáo án, bài giảng , luận văn, luận án, đồ án, bài tập lớn về tất cả các lĩnh vực ki...

Ecological Orbits: How Planets Move and Populations Grow LEV GINZBURG MARK COLYVAN OXFORD UNIVERSITY PRESS Ecological Orbits This page intentionally left blank Ecological Orbits How Planets Move and Populations Grow LEV GINZBURG MARK COLYVAN 1 2004 1 Oxford New York Auckland Bangkok Buenos Aires Cape Town Chennai Dar es Salaam Delhi Hong Kong Istanbul Karachi Kolkata Kuala Lumpur Madrid Melbourne Mexico City Mumbai Nairobi S ˜ ao Paulo Shanghai Taipei Tokyo Toronto Text Copyright © 2004 by Applied Biomathematics Artwork by Amy Dunham © 2002 Applied Biomathematics Published by Oxford University Press, Inc., 198 Madison Avenue, New York, New York 10016 www.oup.com Oxford is a registered trademark of Oxford University Press All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted, in any form or by any means, electronic, mechanical, photocopying, recording, or otherwise, without the prior permission of Oxford University Press. Library of Congress Cataloging-in-Publication Data Ginzburg, Lev R. Ecological orbits: how planets move and populations grow / Lev Ginzburg, Mark Colyvan. p. cm. Includes bibliographical references (p. ). ISBN 0-19-516816-X 1. Population biology. 2. Ecology. I. Colyvan, Mark. II. Title. QH352.G55 2003 577.8'8—dc21 2003048690 135798642 Printed in the United States of America on acid-free recycled paper To Tatyana (1946–2000) Difficulty in imagining how theory can adequately describe nature is not a proof that theory cannot. —Robert MacArthur (1930–1972) Neruda: Le metafore? . . . Quando parli di una cosa, la paragonono ad un’ altra. . . . Postino: É semplice! Perchè questo nome é cosí complicato? [Neruda: Metaphors? . . . It’s when you speak of one thing, com- paring it to another. . . . Postino: That’s simple! Why do they use such a complicated name?] —Dialogue between the characters Pablo Neruda and the postman in the movie Il Postino (1995) Preface The main focus of this book is the presentation of the “inertial” view of population growth. This view provides a rather simple model for complex population dynamics, and is achieved at the level of the single species, without invoking species interactions. An important part of our account is the maternal effect. Invest- ment of mothers in the quality of their daughters makes the rate of reproduction of the current generation depend not only on the current environment but also on the environment experienced by the preceding generation. The inertial view is a significant departure from traditional ecological theory, which has been developing within the Lotka– Volterra framework for close to a century. One way to see this departure is to focus attention away from the growth rate as the sole variable responding to the environment, and toward “ac- celeration,” or the rate of change of the growth rate between consecutive generations. More precisely, our suggestion is that population growth is a second-order dynamic process at the single-species level, and the second-order character is not nec- essarily the result of species interactions. If the inertial view of population growth proves correct, a great deal of current theory on population growth will need to be rethought and revised. As will become clear, our inspiration for looking at ecology in the way we do comes from similar moves in physics—in par- ticular, the move from Aristotelian to Newtonian physics. So let us say a few words in defense of our apparent “physics envy.” Many biologists and ecologists find deference to physics, as the viii Preface Alfred James Lotka (1880–1986) science to which all other sciences must aspire, somewhat dis- tasteful. Those who find this deference to physics unreasonable are generally concerned by the inappropriateness of the meth- ods of physics to other branches of science. They suggest Demography and Population Demography and Population Bởi: OpenStaxCollege Earth’s population, which recently grew to billion, is always on the move (Photo courtesy of David Sim/flickr) We recently hit a population milestone of seven billion humans on the earth’s surface The rapidity with which this happened demonstrated an exponential increase from the time it took to grow from five billion to six billion people In short, the planet is filling up How quickly will we go from seven billion to eight billion? How will that population be distributed? Where is population the highest? Where is it slowing down? Where will people live? To explore these questions, we turn to demography, or the study of populations Three of the most important components affecting the issues above are fertility, mortality, and migration The fertility rate of a society is a measure noting the number of children born The fertility number is generally lower than the fecundity number, which measures the potential number of children that could be born to women of childbearing age Sociologists measure fertility using the crude birthrate (the number of live births per 1,000 people per year) Just as fertility measures childbearing, the mortality rate is a measure of the number of people who die The crude death rate is a number derived from the number of deaths per 1,000 people per year When analyzed together, fertility and mortality rates help researchers understand the overall growth occurring in a population Another key element in studying populations is the movement of people into and out of an area Migration may take the form of immigration, which describes movement into an area to take up permanent residence, or emigration, which refers to movement out of an area to another place of permanent residence Migration might be voluntary (as 1/8 Demography and Population when college students study abroad), involuntary (as when Somalians left the drought and famine-stricken portion of their nation to stay in refugee camps), or forced (as when many Native American tribes were removed from the lands they’d lived in for generations) Population Growth Changing fertility, mortality, and migration rates make up the total population composition, a snapshot of the demographic profile of a population This number can be measured for societies, nations, world regions, or other groups The population composition includes the sex ratio (the number of men for every hundred women) as well as the population pyramid (a picture of population distribution by sex and age) This population pyramid shows the breakdown of the 2010 American population according to age and sex (Graph courtesy of Econ Proph blog and the U.S Census Bureau) Varying Fertility and Mortality Rated by Country As the table above illustrates, countries vary greatly in fertility rates and mortality rates—the components that make up a population composition (Chart courtesy of CIA World Factbook 2011) Country Population (in millions) Fertility Rate Mortality Rate Sex Ratio Male to Female Afghanistan 29.8 5.4% 17.4% 1.05 Sweden 9.1 1.7% 10.2% 0.98 United States of America 313.2 2.1% 8.4% 0.97 2/8 Demography and Population Comparing these three countries reveals that there are more men than women in Afghanistan, whereas the reverse is true in Sweden and the United States Afghanistan also has significantly higher fertility and mortality rates than either of the other two countries Do these statistics surprise you? How you think the population makeup impacts the political climate and economics of the different countries? Demographic Theories Sociologists have long looked at population issues as central to understanding human interactions Below we will look at four theories about population that inform sociological thought: Malthusian, zero population growth, cornucopian, and demographic transition theories Malthusian Theory Thomas Malthus (1766–1834) was an English clergyman who made dire predictions about earth’s ability to sustain its growing population According to Malthusian theory, three factors would control human population that exceeded the earth’s carrying capacity, or how many people can live in a given area considering the amount of available resources He identified these factors as war, famine, and disease (Malthus 1798) He termed these “positive checks” because they increased mortality rates, thus keeping the population in check, so to speak These are countered by “preventative checks,” which also seek to control the population, but by reducing fertility rates; preventive checks include birth control and celibacy Thinking practically, Malthus saw that people could only produce so much food in a given year, yet the population was increasing at an exponential rate Eventually, he thought people would run out of food and begin to starve They would go to war over the increasingly scarce resources, reduce the population to a manageable level, and the cycle would begin anew Of course, this has not ...RESEARCH Open Access Permitted water pollution discharges and population cancer and non-cancer mortality: toxicity weights and upstream discharge effects in US rural-urban areas Michael Hendryx 1,2,4* , Jamison Conley 1,3 , Evan Fedorko 1,3 , Juhua Luo 1,2 and Matthew Armistead 1 Abstract Background: The study conducts statistical and spatial analyses to investigate amounts and types of permitted surface water pollution discharges in relation to population mortality rates for cancer and non-cancer causes nationwide and by urban-rural setting. Data from the Environmental Protection Agency’s (EPA) Discharge Monitoring Report (DMR) were used to measure the location, type, and quantity of a selected set of 38 discharge chemicals for 10,395 facilities across the con tiguous US. Exposures were refined by weighting amounts of chemical discharges by their estimated toxicity to human health, and by estimating the discharges that occur not only in a local county, but area-weighted discharges occurring upstream in the same watershed. Centers for Disease Control and Prevention (CDC) mortality files were used to measure age-adjusted population mortality rates for cancer, kidney disease, and total non-cancer causes. Analysis included multiple linear regressions to adjust for population health risk covariates. Spatial analyses were conducted by applying geographically weighted regression to examine the geographic relationships between releases and mortality. Results: Greater non-carcinogenic chemical discharge quantities were associated with significantly higher non- cancer mortality rates, regardless of toxicity weighting or upstream discharge weighting. Cancer mortality was higher in association with carcinogenic discharges only after applying toxicity weights. Kidney disease mortality was related to higher non-carcinogenic discharges only when both applying toxicity weights and including upstream discharges. Effects for kidney mortality and total non-cancer mortality were stronger in rural areas than urban areas. Spatial results show correlations between non-carcinogenic discharges and cancer mortality for much of the contiguous United States, suggesting that chemicals not currently recognized as carcinogens may contribute to cancer mortality risk. The geographically weighted regression results suggest spatial variability in effects, and also indicate that some rural communities may be impacted by upstream urban discharges. Conclusions: There is evidence that permitted surface water chemical discharges are related to population mortality. Toxicity weights and upstream discharges are important for understanding some mortality effects. Chemicals not currently recognized as carcinogens may nevertheless play a role in contributing to cancer mortality risk. Spatial models allow for the examination of geographic variability not captured through the regression models. Keywords: Age-adjusted mortality, Spatial analysis, Water pollution, Cancer, Kidney disease, Rural-urban differences * Correspondence: mhendryx@hsc.wvu.edu 1 West Virginia Rural Health Research Center, West Virginia University, Morgantown, USA Full list of author information is available at the end of the article Hendryx et al. International Journal of Health Geographics 2012, 11:9 http://www.ij-healthgeographics.com/content/11/1/9 INTERNATIONAL JOURNAL OF HEALTH GEOGRAPHICS © 2012 Hend ryx et al; licensee BioMed Central Ltd. This is an Open Access article distributed under the term s of the Cre The World Health Organization’s INFORMATION SERIES ON SCHOOL HEALTH DOCUMENT 8 Family Life, Reproductive Health, and Population Education: Key Elements of a Health-Promoting School WHO gratefully acknowledges the generous financial contributions to support the layout and printing of this document from: the Division of Adolescent and School Health, National Center for Chronic Disease Prevention and Health Promotion, Centers for Disease Control and Prevention, Atlanta, Georgia, USA. The principles and policies of each of the above agencies are governed by the relevant decisions of its governing body and each agency implements the interventions described in this document in accordance with these principles and policies and within the scope of its mandate. WHO UNICEF ii WHO INFORMATION SERIES ON SCHOOL HEALTH This document is part of the WHO Information Series on School Health. Each document in this series provides arguments that can be used to gain support for addressing impor- tant health issues in schools. Each document illustrates how selected health issues can serve as entry points in planning, implementing, and evaluating health interventions as part of the development of a Health-Promoting School. Other documents in this series include the following: • Local Action: Creating Health-Promoting Schools (WHO/NMH/HPS/00.4) • Strengthening Interventions to Reduce Helminth Infections: An Entry Point for the Development of Health-Promoting Schools (WHO/HPR/HEP/96.10) • Violence Prevention: An Important Element of a Health-Promoting School (WHO/HPR/HEP/98.2) • Healthy Nutrition: An Essential Element of a Health-Promoting School (WHO/HPR/HEP/98.3) • Tobacco Use Prevention: An Important Entry Point for the Development of a Health- Promoting School (WHO/HPR/HEP/98.5) • Preventing HIV/AIDS/STI and Related Discrimination: An Important Responsibility of Health-Promoting Schools (WHO/HPR/HEP/98.6) • Sun Protection: An Important Element of a Health-Promoting School (WHO/FHE and WHO/NPH/02.6) • Creating an Environment for Emotional and Social Well-Being: An Important Responsibility for a Health-Promoting and Child-Friendly School (WHO/MNH and WHO/NPH, 2003) • Skills for Health, Skills-Based Health Education including Life Skills: An important component of a Child Friendly/Health-Promoting School (WHO/NPH and UNICEF, 2003) • Creating a Safe and Healthy Physical Environment: A Key Component of a Health- Promoting School, (WHO/NPH and WHO/PHE, 2003) Documents can be downloaded from the Internet site of the WHO Global School Health Initiative (http://www.who.int/school-youth-health) or they can be requested in print by contacting the Department of Noncommunicable Disease Prevention and Health Promotion, World Health Organization, 20 Avenue Appia, 1211 Geneva 27, Switzerland, Fax (+41 22) 791-4186. In an effort to provide you with the most useful and user-friendly material, we would appreciate your comments. From where did you receive this document, and how did you hear about it? Did you find this document useful for your work? Why or why not? What do you like about this document? What would you change? Do you have any other comments related to content, design, user-friendliness, or other issues related to this document? Please send your feedback to: School Health/Youth Health Promotion Unit Department of Noncommunicable Disease Prevention and Health Promotion World Health Organization, 20 Avenue Appia, 1211 Geneva 27, BioMed Central Page 1 of 7 (page number not for citation purposes) Health and Quality of Life Outcomes Open Access Research Health-related quality of life in patients waiting for major joint replacement. A comparison between patients and population controls Johanna Hirvonen* 1,2 , Marja Blom 1,3,4 , Ulla Tuominen 1,2 , Seppo Seitsalo 5 , Matti Lehto 6 , Pekka Paavolainen 5,7 , Kalevi Hietaniemi 4 , Pekka Rissanen 8 and Harri Sintonen 2 Address: 1 National Research and Development Centre for Welfare and Health, Helsinki, Finland, 2 University of Helsinki, Finland, 3 Academy of Finland, 4 HUCH, Jorvi Hospital, Espoo, Finland, 5 Orton Orthopaedic Hospital, Helsinki, Finland, 6 Coxa, Hospital for Joint Replacement, Medical Research Fund of Tampere University Hospital, Finland, 7 HUCH, Surgical Hospital, Helsinki, Finland and 8 University of Tampere, Finland Email: Johanna Hirvonen* - johanna.hirvonen@stakes.fi; Marja Blom - marja.blom@stakes.fi; Ulla Tuominen - ulla.tuominen@stakes.fi; Seppo Seitsalo - seppo.seitsalo@invalidisaatio.fi; Matti Lehto - matti.lehto@coxa.fi; Pekka Paavolainen - pekka.paavolainen@invalidisaatio.fi; Kalevi Hietaniemi - kalevi.hietaniemi@hus.fi; Pekka Rissanen - pekka.rissanen@uta.fi; Harri Sintonen - harri.sintonen@helsinki.fi * Corresponding author Abstract Background: Several quality-of-life studies in patients awaiting major joint replacement have focused on the outcomes of surgery. Interest in examining patients on the elective waiting list has increased since the beginning of 2000. We assessed health-related quality of life (HRQoL) in patients waiting for total hip (THR) or knee (TKR) replacement in three Finnish hospitals, and compared patients' HRQoL with that of population controls. Methods: A total of 133 patients awaiting major joint replacement due to osteoarthritis (OA) of the hip or knee joint were prospectively followed from the time the patient was placed on the waiting list to hospital admission. A sample of controls matched by age, gender, housing and home municipality was drawn from the computerised population register. HRQoL was measured by the generic 15D instrument. Differences between patients and the population controls were tested by the independent samples t-test and between the measurement points by the paired samples t-test. A linear regression model was used to explain the variance in the 15D score at admission. Results: At baseline, 15D scores were significantly different between patients and the population controls. Compared with the population controls, patients were worse off on the dimensions of moving (P < 0.001), sleeping (P < 0.001), sexual activity (P < 0.001), vitality (P < 0.001), usual activities (P < 0.001) and discomfort and symptoms (P < 0.001). Further, psychological factors – depression (P < 0.001) and distress (P = 0.004) – were worse among patients than population controls. The patients showed statistically significantly improved average scores at admission on the dimensions of moving (P = 0.026), sleeping (P = 0.004) and discomfort and symptoms (P = 0.041), but not in the overall 15D score compared with the baseline. In patients, 15D score at baseline (P < 0.001) and body mass index (BMI) (P = 0.020) had an independent effect on patients' 15D score at hospital POSITIVE PERIODIC SOLUTIONS OF FUNCTIONAL DISCRETE SYSTEMS AND POPULATION MODELS YOUSSEF N. RAFFOUL AND CHRISTOPHER C. TISDELL Received 29 March 2004 and in rev ised form 23 August 2004 We apply a cone-theoretic fixed point theorem to study the existence of positive pe- riodic solutions of t he nonlinear system of functional difference equations x(n +1)= A(n)x(n)+ f (n,x n ). 1. Introduction Let R denote the real numbers, Z the integers, Z − the negative integers, and Z + the non- negative integers. In this paper we explore the existence of positive periodic solutions of the nonlinear nonautonomous system of difference equations x(n +1)= A(n)x(n)+ f  n,x n  , (1.1) where, A(n) = diag[a 1 (n),a 2 (n), ,a k (n)], a j is ω-periodic, f (n,x):Z × R k → R k is con- tinuous in x and f (n,x)isω-p eriodic in n and x,wheneverx is ω-periodic, ω ≥ 1isan integer. Let ᐄ be the set of all real ω-periodic sequences φ : Z → R k . Endowed with the maximum norm φ=max θ∈Z  k j=1 |φ j (θ)| where φ = (φ 1 ,φ 2 , ,φ k ) t , ᐄ is a Banach space. Here t stands for the transpose. If x ∈ ᐄ,thenx n ∈ ᐄ for any n ∈ Z is defined by x n (θ) = x(n + θ)forθ ∈ Z. The existence of multiple positive periodic solutions of nonlinear functional di fferen- tial equations has been studied extensively in recent years. Some appropriate references are [1, 14]. We are particularly motivated by the work in [8] on functional differential equations and the work of the first author in [4, 11, 12] on boundary value problems involving functional difference equations. When working with certain boundary value problems whether in differential or dif- ference equations, it is customary to display the desired solution in terms of a suitable Green’s function and then apply cone theory [2, 4, 5, 6, 7, 10, 13]. Since our equation (1.1) is not this type of boundary value, we obtain a variation of parameters formula and then try to find a lower and upper estimates for the kernel inside the summation. Once those estimates are found we use Krasnoselskii’s fixed point theorem to show the existence of a positive periodic solution. In [11], the first author studied the existence of periodic solutions of an equation similar to (1.1) using Schauder’s second fixed point theorem. Copyright © 2005 Hindawi Publishing Corporation Advances in Difference Equations 2005:3 (2005) 369–380 DOI: 10.1155/ADE.2005.369 370 Positive periodic solutions Throughout this paper, we denote the product of y(n)fromn=a to n = b by  b n=a y(n) with the understanding that  b n=a y(n) = 1foralla>b. In [12], the first author considered the scalar difference equation x(n +1)= a(n)x(n)+h(n) f  x  n − τ(n)  , (1.2) where a(n), h(n), and τ(n)areω-periodic for ω an integer with ω ≥ 1. Under the assump- tions that a(n), f (x), and h(n) are nonnegative with 0 <a(n) < 1foralln ∈ [0, ω − 1], it was shown that (1.2) possesses a positive per iodic solution. In this paper we generalize (1.2) to systems with infinite delay and address the existence of positive periodic solutions of (1.1) in the case a(n) > 1. Let R + = [0,+∞), for each x = (x 1 ,x 2 , ,x n ) t ∈ R n ,thenormofx is defined as |x|=  n j=1 |x j |. R n + ={(x 1 ,x 2 , ,x n ) t ∈ R n : x j ≥ 0, j = 1,2, ,n}. Also, we denote f = ( f 1 , f 2 , , f k ) t ,wheret stands for transpose. Now we list the following conditions. (H1) a( n) = 0foralln ∈ [0,ω − 1] with  ω−1 s=0 a j (s) = 1forj = 1,2, ,k. (H2) If 0 <a(n) < 1foralln ∈ [0,ω − 1] then, f j (n,φ n ) ≥ 0foralln ∈ Z and φ : Z → R n + , j ... society enters a phase of population stability Overall population may even decline Sweden and the United States are considered Stage 4/8 Demography and Population Current Population Trends As mentioned... rate, and therefore, a comparatively moderate projected population growth (Graph courtesy of USAID) 5/8 Demography and Population Projected Population in Europe This chart shows the projected population. .. well as the population pyramid (a picture of population distribution by sex and age) This population pyramid shows the breakdown of the 2010 American population according to age and sex (Graph