Spatial diffusion of COVID-19 in Algeria during the third wave

The differential geographic impact of the third wave of COVID-19 is unknown in Algeria. We thus analyze the spatiotemporal variations of cases and deaths of COVID-19 in Algeria, between January and mid-August 2021. Cases and deaths due to COVID-19 were aggregated at the wilaya (province) level. The space-time permutation scan statistic was applied retrospectively to identify spatial-temporal clusters of COVID-19 cases and deaths. We detected 14 spatio-temporal clusters of COVID-19 cases, with only one high risk cluster. Among the 13 low risk clusters, 7 clusters emerged before the start of the third wave and were mostly located in wilayas with lower population density compared to the clusters that emerged during the third wave. For deaths, the largest geographic low-risk cluster emerged in southern Algeria, between April and early July 2021. Northern and coastal wilayas should be prioritized when allocating resources and implementing various quarantine and isolation measures to slow viral transmission.

Predictive Role of Population Density and Use of Public Transport for Major Outcomes of SARS-CoV-2 Infection in the Italian Population: An Ecological Study

BACKGROUND

This study aimed at assessing how population density (PD), aging index (AI), use of public transport (URPT), and PM10 concentration (PI) modulated the trajectory of the main COVID-19 pandemic outcomes in Italy, also in the recrudescence phase of the epidemic.

STUDY DESIGN

Ecological study.

METHODS

For each region, we recovered data about cases, deaths, and case fatality rate (CFR) recorded since both the beginning of the epidemic and September 1, 2020. Data about total hospitalizations were included as well.

RESULTS

PD correlated with, and was the best predictor of, total and partial cases, total and partial deaths, and total hospitalizations. Moreover, URPT correlated with, and was the best predictor of, total CFR. Besides, PI correlated significantly with total and partial cases, total and partial deaths, and total hospitalizations.

CONCLUSION

PD explains COVID-19 morbidity, mortality, and severity while URPT is the best predictor of disease lethality. These findings should be interpreted with caution due to the ecological fallacy.

Effectiveness of population density as natural social distancing in COVID19 spreading

Recently, many countries have decided to reopen gradually and some of them have thought that social distancing has not had a significant effect. In our study, a new view of the importance of social distancing to prevent the spread of coronavirus has been presented in terms of the relationship between peak day and peak period and population density of nine countries. Data for nine different countries in different coronavirus situations have been analyzed. The analysis process was applied by using three programs, namely; WebPlotDigitizer, WSxM and Origin. The results provide evidence of the effectiveness of social distancing by calculation of the effect of population density on coronavirus infection. That was applied by two stages, the first one by determination of two different groups of countries depending on the rate and range of coronavirus spread. These two groups were countries with developed and developing COVID19 which lead to calculate the peak day and the period times of developed groups. Then, analysis of that data with population density was evaluated to indicate there are significant effects of population density on peak day and peak period times which explain the importance of social distancing between people to manage and control that. The results showed that there are increasing in peak day and peak period times with increasing the population density.

Older Adult Lifespace Varies by Driving Status and Residential Population Density

Individual- and environmental-level factors may explain differential trajectories in lifespace mobility in older adults. The current study tested whether driving status was associated with lifespace, whether lifespace change varied by driving status, and whether residential context moderated the relationship between driving status and lifespace. Participants were older adults ages 65 to 94 (mean = 73.6 + 5.9) enrolled in the Advanced Cognitive Training for Independent and Vital Elderly Study (N = 2,792). Lifespace and driving status were assessed at baseline and first, second, third, and fifth annual follow-up visits. Residential population density was measured as the population density for participants' enrollment site counties. Two sites were categorized as low density (< 600 per square mile) and four sites were categorized as high density (> 1,200 per square mile). Multilevel longitudinal models tested relationships between driving status, residential population density, and lifespace over five years. After controlling for potential confounders, results indicated that non-drivers had smaller mean lifespace than drivers across five years. Rates of lifespace declines did not differ between drivers and non-drivers. Non-drivers at baseline residing in low population density areas had smaller lifespace than non-drivers in high population density areas and all drivers regardless of population density. The findings suggest that residential context plays a role in older adults' travel behaviors and choices. Further research is needed to understand what residential characteristics support or hinder lifespace maintenance for older adult non-drivers, such as availability and usability of transportation and walkability.

Growth in overcrowded housing: a comparison of the states

"The present article reports on a research project that is seeking greater understanding of the prevalence of overcrowding [in the United States] and its causes. First we review the definition of overcrowding and describe differences between renters and owners. Next we document the state-by-state variation in crowding levels among renters. Then we explore some of the factors that may explain this variation."

[Land planning in Zaire through the spatial distribution of the population]

"Land planning in Zaire is examined through the analysis of population distribution by density and potential. The difference between these two techniques is that the calculation of population potential takes into account a genuinely geographical element, which is the distance between one given place and the other places within the area under consideration.... Taking potential as a criterion leads to developing an axis of communication from one end of the country to the other through densely populated, high-potential areas. Population density leads to a limited axis in each of the two regions with a high density of human occupation. In conclusion, the contribution of distance in land planning is to facilitate access for larger numbers of people and increase potential exchanges and contacts with other territories." (SUMMARY IN ENG)

Topography and spatial population dualism in the People's Republic of China (1933-1990)

"Looking at half a century of available data, a sharp spatial dualism is observed in the regional population distribution of the People's Republic of China. The vast share of the PRC's population is located in the Eastern and South-Eastern regions. Two topographical variables related to accessibility, distance from the eastern seaboard and elevation, seem to be at the core of this dualism. Their isolated and combined effects upon the spatial distribution of the PRC's population are examined for the period 1933-1990. It is documented that the population concentration in certain regions of the PRC is not so much because of their proximity to the seaboard, but because of their low elevation, especially in the eastern part of the nation. Also documented is a result indicating that in time the combined effects of these impedances on the regional population distribution in the PRC is linearly declining."

[Java's large population: two centuries of explanations]

"Explanation of demographic imbalance between Java and the socalled 'Outer-Islands' has been numerous for almost two centuries. Authors generally considered that the great density of population was a direct consequence of the high fertility of Javanese soils. Some of them, however, connected it with an early economical 'take-off'. But none of these analyses can explain why marginally suitable regions from an agricultural point of view were overcrowded especially when their economical development was low. We propose another explanation scheme on an historical basis." (SUMMARY IN ENG)

Urbanization and childhood leukaemia in Taiwan

BACKGROUND

In the 1980s socioeconomic development was dramatically rapid in the urbanized municipalities of Taiwan due to a prospering economy. This study addressed the question: Could differences in the incidence of childhood leukaemia (age <15) be demonstrated between urban and rural communities in Taiwan between 1981 and 1990?

METHODS

The log-linear regression model was used to assess the effects of age, level of urbanization, and calendar year on the variation of childhood leukaemia incidence rates between 1981 and 1990.

RESULTS

Between 1981 and 1990, the overall incidence rate of childhood leukaemia increased by 20% (rate ratio (RR) = 1.2, 95% CI: 1.0-1.5). As compared to rural areas, metropolitan regions showed a significantly higher incidence rate during the study period (RR = 1.3, 95% CI: 1.1-1.6). This urban-rural difference was particularly notable among children <5 years old (RR = 1.5, 95% CI: 1.2-1.9). Dose-response analysis further indicated that risk of childhood leukaemia was monotonically associated with levels of urbanization. The significant gradient in the risk of childhood leukaemia with urbanization was contributed solely by children in the 0-4 years age group.

CONCLUSIONS

We noticed a relationship between urbanization and risk of leukaemia in children. Because of a dramatic influx of people into metropolitan areas during the 1980s, our findings may have provided support for the putative association between 'population mixing' or 'population density' and risk of childhood leukaemia. Whether such association can be attributable to virus infection or other aetiologically related leukemogens warrants further investigations.

Poor people on the move: county-to-county migration and the spatial concentration of poverty

"Poverty rates in high-poverty and low-poverty rural [U.S.] counties, and, thus, the spatial concentration of poverty, are affected by poverty-specific differences in in-migration and out-migration patterns. These patterns are investigated using 1985-90 county-to-county migration data from the decennial census. Effects on poverty rates of four migration flows (in- and out-migration of poor, in- and out-migration of nonpoor) are quantified, and their impacts on spatial concentration of poverty are assessed. The effect of selected county characteristics on the migration of the poor and nonpoor in nonmetro counties [is] estimated."

Population and employment density functions revisited: a spatial interaction approach

"This article proposes a generalized urban spatial structure and transportation network, and adapts the Garin-Lowry model to simulate both population and service employment densities in this hypothetical, yet realistic, city. The model is solved numerically while varying exogenous factors such as the distance friction coefficients and the spatial distribution of basic employment.... The results are generalized by estimating, via regression analysis, density functions over a large sample of simulated density patterns, pointing to the critical importance of transportation costs and basic employment distribution, and providing a basis for further empirical studies."

The relationship between population density and cancer mortality in Taiwan

Many investigators have examined urbanization gradients in cancer rates. The purpose of this report was to identify urban-rural trends in cancer mortality rates (1982-1991) for municipalities in Taiwan. For this purpose, Taiwan's municipalities were classified as rural, suburban, urban, or metropolitan, using population density as an ordinal indicator of the degree of urbanization. Average annual age-adjusted, site-specific cancer mortality rates were calculated for both sexes within each population density group. Significant increasing trends with more urbanization were observed in mortality rates for cancers of the lung, pancreas, and kidney among both males and females, as well as male prostate cancer, and female breast and ovary cancer. In addition, this study revealed a significant rural excess for nonmelanoma skin cancer among both males and females, as well as male non-Hodgkin's lymphoma, and cancers of the female bone, and female connective tissue. Analytic studies for sites with consistent urban-rural trends may be fruitful in identifying the aspect of population density, or other unmeasured factors, that contribute to these trends.

World population in a grid of spherical quadrilaterals

"We report on a project that converted subnational population data to a raster of cells on the earth. We note that studies using satellites as collection devices yield results indexed by latitude and longitude. Thus it makes sense to assemble the terrestrial arrangement of people in a compatible manner. This alternative is explored here, using latitude/longitude quadrilaterals as bins for population information.... The results to date of putting world boundary coordinates together with estimates of the number of people are described. The estimated 1994 population of 219 countries, subdivided into 19,032 polygons, has been assigned to over six million five minute by five minute quadrilaterals covering the world."

The facts about the urban exodus

"Urban deconcentration is the most dominant and consistent feature of population movement in Britain nowadays.... The scale of urban out-migration varies over time, some types of people and places are more fully represented in the urban exodus than others, and the net figures hide the fact that quite sizeable numbers of people move in the opposite direction.... The research was based largely in 1991 Population Census data on people who changed address within Great Britain during the year preceding Census night, focusing mainly on migration between local authority districts grouped according to their degree of 'urbanness' and their distance from the main metropolitan centres."

Density and the journey to work

"This paper evaluates the influence of residential density on commuting behavior across U.S. cities while controlling for available opportunities, the technology of transportation infrastructure, and individual socio-economic and demographic characteristics. The measures of metropolitan and local density are addressed separately.... Regressions are conducted to predict commuting time, speed, and distance, by mode of travel on a cross-section of individuals nationally and city by city. The results indicate that residential density in the area around the tripmaker's home is an important factor: the higher the density the lower the speed and the shorter the distance.... The paper suggests a threshold density at which the decrease in distance is overtaken by the congestion effects resulting in a residential density between 7,500 and 10,000 persons per square mile (neither the highest nor lowest) with the shortest duration auto commutes."

The earnings experience of rural-urban migrants in Korea

"Migration models in the Harris-Todaro tradition imply that urban informal sector earnings are less than rural sector earnings. Examining the situation for [South] Korea, we find that both urban formal and informal sector earnings exceed earnings opportunities in rural areas, making rural-urban migration the best decision for the individual and for the Korean economy in terms of maximizing output.... The implication for policy makers is that government efforts may be better directed toward mitigating the externalities caused by over-crowding, rather than attempting to influence population movements."

Preliminary evidence for a theory of the fractal city

"In this paper, we argue that the geometry of urban residential development is fractal. Both the degree to which space is filled and the rate at which it is filled follow scaling laws which imply invariance of function, and self-similarity of urban form across scale. These characteristics are captured in population density functions based on inverse power laws whose parameters are fractal dimensions. First we outline the relevant elements of the theory in terms of scaling relations and then we introduce two methods for estimating fractal dimension based on varying the size of cities and the scale at which their form is detected. Exact and statistical estimation techniques are applied to each method respectively generating dimensions which measure the extent and the rate of space filling. These methods are then applied to residential development patterns in six industrial cities in the northeastern United States...."

Demographic response to rural restructuring and counterurbanisation in South Australia, 1981-1991

"Using South Australia as a case study, this paper seeks to trace and demonstrate two processes (counterurbanisation and rural restructuring) whose effects overlap to differentiate and characterise the population geography of...two zones, separated by a transition along the outer fringe of Adelaide's urban field.... In the demographic core zone [rural restructuring] has been partly offset by continued counterurbanisation, resulting in demographic mixing and rural dilution. The 1981-91 population growth in rural communities is shown to be more a function of population density at the outset of the period than of initial population size. Demographic growth...is shown to conform to a simple unidimensional scale, allowing the production of a clear, easily interpretable typology of rural demographic change with few non-conforming statistical areas. At a local level within individual rural communities, demographic decline is shown to be accompanied by increased concentration of the population into small towns, while demographic growth is associated with deconcentration."