Modelling population density over time: how spatial distance matters

Canada is unusual among advanced industrial democracies in having some provinces which regularly have greater voter turnouts for provincial than for federal elections. Provincial and federal turnouts by province in Canada are analyzed for the 1945-1998 period using multiple regression analysis, both for each set of elections and by comparing differences between the two. Federal turnout has declined over the years but provincial turnout appears to have increased slightly. Although the effects found here largely confirm previous findings about the relative effects of different types of variables found for the Canadian federal level only, several of the political explanations previously supported in cross-national research find less support. Instead, region, population density, months since the last federal or provincial election, and season of the year generally have greater and sometimes more consistent effects. This suggests the need for more studies of turnout in democracies at sub-central levels.

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DENSIDAD POBLACIONAL DE CUATRO ESPECIES DE ERIZO (ECHINODERMATA: ECHINOIDEA) EN EL ARRECIFE DE LA ENTREGA, OAXACA

CICIMAR Oceánides ◽

10.37543/oceanides.v20i1-2.22 ◽

2005 ◽

Vol 20 (1-2) ◽

pp. 65

Author(s):

P. Zamorano ◽

G. E. Leyte-Morales

Keyword(s):

Population Density ◽

Sea Urchin ◽

Sea Urchins ◽

Depth Range ◽

Deep Zone ◽

Total Abundance ◽

Subsequent Increase ◽

Shallow Zone ◽

Over Time ◽

Shallow Part

De octubre de 2002 a agosto de 2003 se realizaron muestreos bimestrales de la abundancia de erizos en el arrecife de La Entrega. El arrecife fue dividido en dos profundidades (somero 0-6 m y profundo 6-12 m). En cada profundidad se realizaron seis transectos de 50 m de largo por 1 m de ancho. La mayor densidad anual correspondió a Diadema mexicanum (5.96±0.85 ind/m2), seguido de Eucidaris thouarsii (0.46±0.14 ind/m2); Echinometra vanbrunti y Toxopneustes roseus presentaron densidades bajas (0.03±0.01 ind/m2 y 0.02±0.01 ind/m2, respectivamente). Las cuatro poblaciones de erizos presentaron diferencias entre profundidades observándose mayor densidad en lo profundo; si consideramos la abundancia total de erizos en el arrecife, no se registraron diferencias temporales. Empero, al analizar por separado las profundidades, sólo E. thouarsii no presentó diferencias temporales en ambas profundidades. En diciembre, las densidades de D. mexicanum y E. thouarsii disminuyeron en lo profundo y aumentaron en lo somero, posiblemente porque sucedió una mortalidad coralina en lo somero del arrecife y el incremento de las algas motivó a estas especies a desplazarse a la parte dañada. Actualmente el arrecife de La Entrega se encuentra en avanzado estado de erosión lo que puede favorecer que la abundancia de erizos se incremente al igual que su actividad bioerosionadora. Population density of four species of sea urchin (Echinodermata: Echinoidea) at La Entrega Reef, Oaxaca Bimonthly samples of sea urchins fauna inhabiting the La Entrega Reef, Oaxaca, Mexico, were obtained from October 2002 to August 2003. The reef area was divided in two sampling zones, corresponding to shallow (0-6 m) and deep (6-12 m) water. Six transects of 50 m length by 1 m wide were sampled in each zone. Greatest annual density corresponded to Diadema mexicanum (5.96 ± 0.85 ind/m2),followed by Eucidaris thouarsii (0.46 ± 0.14 ind/m2); Echinometra vanbrunti and Toxopneustes roseus presented low densities (0.03 ± 0.01 indv/m2 and 0.02 ± 0.01 ind/m2, respectively). Density of the four populations varied considerably and higher densities were observed in the deep zone. Total abundance of sea urchins (shallow and deep samples) did not vary significantly over time. Abundance per depth range, however, was different over time for all species except for E. thouarsii. In December densities of D. mexicanum and E. thouarsii decreased in the deep zone and increased in the shallow zone, due to massive mortality of coral in the shallow part of the reef and to subsequent increase of algal coverage attracting these species to the shallowest part of the reef. The La Entrega reef is presently in an advanced state of erosion that could favor an increase of sea urchins abundance and of their bioerosion activity.

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Contrasting effects of climate and population density over time and life stages in a long‐lived seabird

Functional Ecology ◽

10.1111/1365-2435.12831 ◽

2017 ◽

Vol 31 (6) ◽

pp. 1275-1284 ◽

Cited By ~ 15

Author(s):

Rémi Fay ◽

Christophe Barbraud ◽

Karine Delord ◽

Henri Weimerskirch

Keyword(s):

Population Density ◽

Life Stages ◽

Over Time

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Self-Reinforcing Processes Governing Urban Sprawl in Belgium: Evidence over Six Decades

Sustainability ◽

10.3390/su12104097 ◽

2020 ◽

Vol 12 (10) ◽

pp. 4097 ◽

Cited By ~ 3

Author(s):

Ahmed Mustafa ◽

Jacques Teller

Keyword(s):

Linear Regression ◽

Population Density ◽

Urban Sprawl ◽

Urban Dispersion ◽

Dispersion Degree ◽

Dispersion Patterns ◽

Study Country ◽

Per Capita ◽

Different Levels ◽

Over Time

Urban sprawl is widely acknowledged as an environmental and socio-economic challenge worldwide. This study examines urban sprawl in Belgium over six decades from 1950 to 2010. We assume that sprawl is a self-reinforcing process, i.e., sprawl is fueling further sprawl over time. The main objective of this study is to examine this assumption. We measure urban sprawl at four different levels in this study: country, regions, municipalities, and 1-km2 cells. Three sprawl indices are employed: the degree of urban dispersion, degree of urban permeation of the landscape, and built-up land uptake per capita. These three indices consider both the growth of built-up areas and population density to measure the magnitude of sprawl. The drivers of urban sprawl have been analyzed at a 1-km2 level. The examined drivers are previous urban dispersion patterns, distance to urban cores, elevation, and slope degree by means of linear regression. Urban sprawl significantly increased between 1950 and 1980, whereas its increase was more moderate between 1980 and 2010. Urban dispersion and permeation strongly affect the Brussels and Flanders regions. The results show that the increase in the degree of dispersion is locally driven by previous values of dispersion; i.e., it provides an adequate milieu for further dispersion. Therefore, our conclusion is that urban sprawl in Belgium tends to be a self-reinforcing process.

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Infection of whitefish (Coregonus lavaretus L. s.l.) by Triaenophorus crassus Forel (Cestoda: Pseudophyllidea): a case study in parasite control

Canadian Journal of Zoology ◽

10.1139/z90-176 ◽

1990 ◽

Vol 68 (6) ◽

pp. 1187-1192 ◽

Cited By ~ 24

Author(s):

Per-Arne Amundsen ◽

Roar Kristoffersen

Keyword(s):

Population Density ◽

Food Selection ◽

Final Host ◽

Coregonus Lavaretus ◽

Parasite Control ◽

Dramatic Decline ◽

Key Factor ◽

Intensive Fishing ◽

Over Time

A case study of Triaenophorus crassus control in two sympatric whitefish populations was carried out in Stuorajavri, northern Norway. The densities of whitefish and pike were markedly reduced by an intensive fishing programme and during the 6 years of investigation, a dramatic decline in T. crassus infection of whitefish was observed. The mechanisms involved in parasite control were elucidated by studying the differences in infestation over time between T. crassus and a related cestode, Diphyllobothrium ditremum, in the two whitefish populations. Reduction in population density of the final host, pike, is suggested as being the key factor in control of T. crassus. Exploitation and reduction of whitefish population density contributed to decreased infection in one of the whitefish populations by influencing its acquisition of parasites via a change in its food selection.

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Modeling Temperature Effects on Population Density of the Dengue Mosquito Aedes aegypti

Insects ◽

10.3390/insects10110393 ◽

2019 ◽

Vol 10 (11) ◽

pp. 393 ◽

Cited By ~ 3

Author(s):

Fadoua El Moustaid ◽

Leah Johnson

Keyword(s):

Dynamical System ◽

Population Density ◽

Aedes Aegypti ◽

Temperature Effects ◽

Adult Population ◽

System Model ◽

Life Stages ◽

Mosquito Density ◽

Temperature Dependent ◽

Over Time

Mosquito density plays an important role in the spread of mosquito-borne diseases such as dengue and Zika. While it remains very challenging to estimate the density of mosquitoes, modelers have tried different methods to represent it in mathematical models. The goal of this paper is to investigate the various ways mosquito density has been quantified, as well as to propose a dynamical system model that includes the details of mosquito life stages leading to the adult population. We first discuss the mosquito traits involved in determining mosquito density, focusing on those that are temperature dependent. We evaluate different forms of models for mosquito densities based on these traits and explore their dynamics as temperature varies. Finally, we compare the predictions of the models to observations of Aedes aegypti abundances over time in Vitòria, Brazil. Our results indicate that the four models exhibit qualitatively and quantitatively different behaviors when forced by temperature, but that all seem reasonably consistent with observed abundance data.

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Prediction Vulnerability Level of Dengue Fever Using KNN and Random Forest

Jurnal RESTI (Rekayasa Sistem dan Teknologi Informasi) ◽

10.29207/resti.v4i3.1926 ◽

2020 ◽

Vol 4 (3) ◽

pp. 531-536 ◽

Cited By ~ 1

Author(s):

Abduh Salam ◽

Sri Suryani Prasetiyowati ◽

Yuliant Sibaroni

Keyword(s):

Growth Rate ◽

Wind Speed ◽

Random Forest ◽

Population Density ◽

Dengue Virus ◽

Dengue Fever ◽

Population Mobility ◽

Density Growth ◽

The Government ◽

Over Time

Indonesia is a country that is prone to Dengue Fever, this happens because Indonesia is a country with a tropical climate. More than 50 years after Indonesia contracted the dengue virus, dengue fever cases have not been resolved, currently the cases that occur are greatly increased over time this happens because of factors that cause dengue fever. By considering this serious problem, the authors created a system that can predict the vulnerability level in Bandung and looks for the factors that most influence from all factors of Dengue Fever using the KNN Algorithm and Random Forest. The results of the system show the results of the best model is KNN algorithm with RMSE 29,26, and from the model shows the most influencing factors are population density, growth rate population mobility, rainfall, wind speed. by utilizing the results of the study, the government can adjust actions to each level of sub-district vulnerability and pay more attention to the factors that most influence dengue fever according to the results of the study.

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Community structure of Auchenorrhyncha (Homoptera) in montane rain forest in Vietnam

Journal of Tropical Ecology ◽

10.1017/s0266467400006301 ◽

1992 ◽

Vol 8 (2) ◽

pp. 169-179 ◽

Cited By ~ 6

Author(s):

Vojtěch Novotný

Keyword(s):

Community Structure ◽

Body Size ◽

Population Density ◽

Species Composition ◽

Rain Forest ◽

Transitional Zone ◽

Spatial Distance ◽

Montane Rain Forest ◽

Dominance Level ◽

Montane Tropical Forest

ABSTRACTThe adult Auchenorrhyncha community within the understorey of a montane tropical forest in Vietnam is described A total of 1132 specimens representing 223 morphospecies and 16 families was found in a 4300-sweep sample None of the species exceeded the 5% dominance level More than half the species are represented by single individuals within the 309 ms of vegetation Spatial community pattern is mosaic like at a scale of hundreds of metres as the similarity of 100 sweep samples does not depend on their spatial distance Areas 1 5–3 km distant from one another differ markedly in their Auchenorrhyncha communities These between-site differences exceed the intra-site community heterogeneity Population density of Auchenorrhyncha species is not correlated with their body size The Auchenorrhyncha community within a forest markedly differs from the community of an adjacent ruderal area A transitional zone between these habitats is intermediate in Auchenorrhyncha species composition

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Urban Form, Growth, and Accessibility in Space and Time: Anatomy of Land Use at the Parcel-Level in a Small to Medium-Sized American City

Sustainability ◽

10.3390/su10124572 ◽

2018 ◽

Vol 10 (12) ◽

pp. 4572 ◽

Cited By ~ 5

Author(s):

Long Zhou ◽

Guoqiang Shen ◽

Yao Wu ◽

Robert Brown ◽

Tian Chen ◽

...

Keyword(s):

Land Use ◽

Population Density ◽

Urban Growth ◽

Urban Form ◽

American City ◽

Path Distance ◽

Urban Accessibility ◽

Time Periods ◽

The City ◽

Over Time

Using the City of Corvallis, Oregon, a small to medium sized American city, as a test-bed, this paper examines the City’s urban growth in relation to urban accessibility. This relationship is explored in an anatomic spatial-temporal fashion, taking account of: the number and size of developed land use parcels over time; urban accessibility from residential to non-residential land use areas; and the statistical relationships between urban form and urban accessibility. This investigation of land use is structured around use-classification and examined within a range of dimensional and demographic measurements over 5-year time periods from 1853 to 2014; concurrently, urban accessibility is measured by the least-cost path distance as calculated through the OD cost matrix analysis in GIS. The results indicate that the city grew spatially at different rates and its urban accessibility experienced both ups and downs over time. The city’s population growth corresponded closely with urban growth and its decreasing population density negatively impacted on the city’s urban accessibility to commerce, industry, and office for most time periods. Significantly, while the urban density increased steadily after 1950s concurrent with an increase in urban sprawl, in contrast to previous studies on the metropolitan condition, the urban density had no evident impact on urban accessibility in Corvallis. Instead, increasing the land-use mix was a more effective and feasible approach to reduce urban travel path distance and enhance accessibility than increasing population density or urban development density. Accordingly, this research provides evidence-based policy recommendations for planning sustainable urban mobility and urban form in small to medium-sized cities.

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