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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Patterns in the dynamics and distribution of insect populations

Gaston, K. J. January 1989 (has links)
No description available.
2

Simulating the Spatial Distribution of Population and Emissions to 2100

Asadoorian, Malcolm O. 05 1900 (has links)
Urbanization and economic development have important implications for many environmental processes including global climate change. Although there is evidence that urbanization depends endogenously on economic variables, long-term forecasts of the spatial distribution of population are often made exogenously and independent of economic conditions. A beta distribution for individual countries/regions is estimated to describe the geographical distribution of population using a 1° x 1° latitude-longitude global population data set. Cross-sectional country/regional data are then used to estimate an empirical relationship between parameters of the beta distribution and macroeconomic variables as they vary among countries/regions. This conditional beta distribution allows the simulation of a changing distribution of population, including the growth of urban areas, driven by economic forecasts until the year 2100. / Abstract in HTML and technical report in PDF available on the Massachusetts Institute of Technology Joint Program on the Science and Policy of Global Change website (http://mit.edu/globalchange/www/).
3

Prostorová dynamika obyvatel v České republice, 1989 - 2007 / Spatial Dynamics of the Population in the Czech Republic, 1989 - 2007

Vobecká, Jana January 2010 (has links)
3 Abstract The aim of the thesis is to describe, analyse and discuss the development of spatial population dynamics in the Czech Republic between 1989 and 2007. Demographic structure and migration, the two components of spatial population dynamics, are analysed using two spatial dimensions, the urban-suburban-rural gradient and the core-periphery region distinction, using quantitative analyses, including gravity regression modelling of migration. The analysis primarily focuses on domestic migration as the main vehicle of spatial population dynamics. It discusses the structure, determinants, and temporal evolution of migration and its consequences on the population structure in different spatial categories. The thesis indicates that suburbanisation has recently become the main factor influencing Czech spatial population dynamics. The key factor determining migration destination is the social status of migrants, whereas age has only secondary importance. However, since Czechs are not very mobile, population dispersal is less large-scale than in Western-Europe. This explains why recent domestic migration patterns have had only a small measurable influence on the social or demographic structures of the population across spatial categories. Key words: suburbanisation, domestic migration, gravity modelling,...
4

An Investigation into Predation, Mortality and Taphonomic Bias inthe Population Distribution of Neptunea contraria from theRed Crag of East Anglia / Påverkan av predation, dödlighet och tafonomihos Neptunea contraria från Red Crag, England

Seale, Alexander January 2016 (has links)
Predation is a key factor in evolutionary dynamics. It disrupts the potential of fossilisation in prey items and is poorly recorded in the fossil record; failed predation in conical marine gastropods is recorded in scars. Quantifying the scar distribution and collection and taphonomic biases present in the fossil record of the gastropod Neptunea contraria, of the Red Crag Formation, Gelasian, Pleistocene, UK is necessary to approach this dynamic. Neptunea contraria is highly abundant in the Red Crag Formation which is easily accessed. The size and scarring on a large number (450+) of individuals was collected, recorded and measured from pre-existing and new material. The size distribution of Neptunea contraria is non-normal and is enriched in larger individuals, the scar distribution – expected to be Poisson – is not so. Taphonomic and Collection bias had a large influence over the size and scar distributions of Neptunea contraria. Material from the same localities shows very different size distributions. The lack of Poisson distribution suggests different rates of unsuccessful predation over life history of Neptunea contraria, assuming the data is valid. / Predation anses vara en viktig faktor inom ekologi och evolution men till vilken grad har effekterna av predation förändrats genom geologisk tid? Det centrala fokuset i denna studie ligger i att frambringa en förståelse av både population- och predationsfördelningen bland marina snäckor av arten Neptunea contraria av Pleistocen ålder från Red Crag-formationen, East Anglia, Storbritannien.Framgångsrik predation resulterar i förstörelsen av snigeln och dess livshistoria registreras i deras skal. Misslyckad predation bevaras i skalen bland individer som överlevt genom ärrbildningar. Det finns ett okänt samband mellan misslyckad och framgångsrik predation.Samlingen av fossilt material från Sedgwick-museet i Cambridge, Storbritannien, ligger till grund för denna studie. Detta material är ofullständigt (d.v.s. material saknas) och noterbart fragmenterat vilket orsakats av nedbrytande processer, därav tafonomi. Denna studie belyser flertalet källor som ger upphov till ett ofullständigt fossilt register, därav processer direkt relaterade till fossilisering och antropogen insamling. Genom att jämföra flertalet uppsättningar av fossilt material som insamlats av olika personer så kan graden av bias i förhållande till insamlingen undersökas. Resultatet av denna studie visar att samlingen av fossila sniglar som för närvarande finns på Sedgwick-museet är ofullständig. Detta är ett tillstånd som uppkommit delvis på grund av inkomplett insamling.Fördelningen av ärr orsakade av misslyckad predation förväntades följa en poissonfördelning. Denna förutsägelse motsägs sannerligen av nuvarande data. Troligtvis har detta förorsakats av en låg ”miss-lyckad predationsfrekvens”, vilket antyder att graden av predation inte är konstant.Sniglar av en större storlek saknar ärr på den övre delen av sina skal, vilket tyder på att frekvensen av misslyckad predation var låg i de juvenila stadierna. (
5

Estruturação populacional, variações fenotípicas e estudos morfométricos em Apis mellifera (Hymenoptera: Apidae) no Brasil / Populational structuration, phenotypic variations and morphometric studies in Apis mellifera (Hymenoptera: Apidae) in Brazil.

Nunes, Lorena Andrade 07 March 2012 (has links)
Apis mellifera é uma espécie de abelha bastante estudada sob diferentes perspectivas, tanto em pesquisas básicas como aplicadas. Possui uma natureza singular associada não só a interesses econômicos como produção de cera, mel, própolis, geléia real, pólen, mas também, por seu potencial agrícola como polinizador. Esta espécie tem sido alvo de muitos estudos morfométricos, principalmente pela sua importância ecológica, pela sua grande capacidade de adaptação, sua ampla distribuição e por serem capazes de se estabelecer eficientemente em diversos ambientes. A morfometria geométrica permite uma análise rigorosa da variação da forma de uma determinada estrutura em organismos de diversos tamanhos, principalmente utilizando métodos de estatística multivariada, além de ser capaz de avaliar a instabilidade no desenvolvimento de um organismo. O presente trabalho teve como objetivo estudar as variações da forma e tamanho em asas e corbículas de operárias de Apis mellifera, provenientes das 5 regiões geográficas do Brasil, utilizando análises morfogeométricas. A existência de padrões de variação de forma e tamanho das abelhas africanizadas no Brasil obtidos há 16 anos em estudo clássico realizado por Diniz-Filho e Malaspina, possibilitou uma análise espaço-temporal comparativa com os resultados obtidos utilizando recursos tecnológicos atuais para a avaliação de dados morfométricos, bem como, verificar por meio das análises de assimetria flutuante a plasticidade fenotípica no tamanho e forma da asa e corbícula dessa espécie, possibilitou ainda, avaliar se condições adversas relacionadas às ações antrópicas influenciam no aumento de desvios na simetria bilateral desses caracteres morfológicos. Foi realizada uma amostragem abrangendo as 5 regiões geográficas do Brasil, pela forma das asa e análises multivariadas verificou-se que existe um padrão geográfico entre as populações de Apis mellifera no Brasil (P < 0,001). Essas variações geográficas podem ser devidas à grande extensão territorial, além da possível associação das diferenças entre ecorregiões. Verificou-se, também, a presença de assimetria flutuante na forma das asas e das corbículas de Apis mellifera em todas as populações estudadas, porém, na análise multivariada e assimetria do tamanho não obteve significância em algumas populações, constatando-se que para estudo de assimetria e distribuição populacional a forma da asa e das corbículas é a análise mais indicada e que apresenta maior precisão. / Apis mellifera is bee specie very studied under different perspectives, as for basic studies to applied ones. They have a singular nature, not only associated to economic issues as wax, honey, propolis, royal jelly and pollen production, but also for their agricultural potential as pollinators. This specie has been long aimed for morphometric studies, because of its ecological importance, easy capacity of adaptation, large distribution and for being able of efficient establishment in diverse environments. The geometric morphometric allows rigorous analyses in shape variation of a given structure in organism of diverse sizes, especially when using multivariate statistics methods, enabling the evaluation of instability in the development of an organism. The present study aim the variations of shape and size in wings and pollen basket from workers of Apis mellifera, acquired at 5 geographic regions of Brazil, using morphogeometric analyses. The existence of variation patters in shape and size of Africanized bees in Brazil, obtained 16 years ago in classic study made by Diniz-Filho and Malaspina, made possible a comparative spatialtemporal analyses with the results obtained in this study, using updated technology resources for evaluation of morphometric data, as well as the phenotypic plasticity exam of size and shape in wings and pollen basket of this specie, using fluctuating asymmetric analysis, and evaluate if diverse conditions made by anthropomorphic actions has influence on the deviation increase among bilateral symmetry of this morphological characters. The sample was made including 5 geographic regions of Brazil. By the wings size shape and multivariate analyses, it was verified the existence of a geographic pattern among Brazilian Apis mellifera populations (P< 0,001). Those geographical variations may be caused due to the big territorial expansion, alongside with the possible association of different ecoregions. It was also verified floating asymmetric in the shape of wings and pollen basket from Apis mellifera in all studied populations, however, in the multivariate analyses the asymmetry in shape was not significant in some populations, showing that, for studies of asymmetry and populational distribution, the shape of wings and pollen basket is the most indicated and precise analyses.
6

Dinâmica populacional e produção secundária de uca (Brachyura: Ocypodidae) no estuário dos rios Piraquê-açú e Piraquê-mirim, ES, Brasil / Population dynamics and secondary production of uca (Brachyura: Ocypodidae) in the estuary of Piraquê-açu and Piraquê-mirim rivers, ES, Brasil

Pereira, Carolina Ortulan 05 September 2014 (has links)
Um estudo de distribuição temporal, proporção sexual e densidade de caranguejos do gênero Uca foi realizado no estuário dos rios Piraquê-Açu e Piraquê-Mirim, Santa Cruz, Espírito Santo, Brazil. A população de caranguejos presentes em 06 áreas dividias em 90 quadrados de 0.75 m² foi coletada mensalmente durante o período de Julho/2012 à Maio/2013. Os caranguejos foram coletados por escavação manual das tocas, identificados e sexados. A temperatura do ar e da água variou entre 21 a 27°C e 22 a 28°C, respectivamente, enquanto que a salinidade variou de 21 a 35. Um total de 5.391 espécimes foi coletado, sendo 2.823 machos e 2.568 fêmeas (sendo 40 ovadas). A densidade média para a população de Uca sp. (subgênero leptuca) variou de 18,01 ± 1,29 (Maio/13) a 62,22 ± 1,51 ind.m-² (Novembro/12), para Uca thayeri de 3,67 ± 0,63 (Julho/12) a 15,29 ± 1,44 ind.m-² (Janeiro/13) e para a população Uca maracoani de 0,83 ± 0,27 ind.m-² (Julho/13) a 10,31 ± 0,73 (Novembro/12). A proporção sexual foi 1:1 para cada espécie estudada. A análise de correspondência canônica indicou que houve influência dos fatores ambientais na densidade dos caranguejos. Entretanto, as variáveis abióticas não foram limitantes para a distribuição das espécies estudadas. A produção secundária para a população de Uca sp. (subgênero leptuca) variou de 7,34 para 50,89 g PSLC m-1 ano-1, para Uca thayeri de 12,10 para 27,65 g PSLC m-1 ano-1 e para a população Uca maracoani de 1,70 para 8,83 g PSLC m-1 ano-1. A análise de regressão multivariada indicou que para a espécie Uca sp. (subgênero leptuca) a quantidade clorofila-a está relacionada com a produtividade desta espécie e para as demais espécies nenhuma das variáveis abióticas estudadas estaria relacionada com sua produtividade. / The temporal distribution, sex ratio and density of the fiddler crab Uca spp. was studied in populations living in the Piraquê-Açu and Piraquê-Mirim estuaries, Santa Cruz, Espírito Santo State, Brazil. Ninety 0.75 m² in 06 areas were used to obtain monthly samples from July 2012 to May 2013. The crabs were collected manually through excavation of burrows, identified and sexed. Air and water temperatures varied from 21 to 27°C and 22 to 28°C, respectively, and the salinity from 21 to 35. A total of 5,391 fiddler crabs were collected, with 2,823 males and 2,568 females (40 ovigerous). The average densities for the three species found were 18,01 ± 1,29 (May/13) to 62,22 ± 1,51 ind.m-² (November/12), 3,67 ± 0,63 (July/12) to 15,29 ± 1,44 ind.m-² (January/13) for Uca thayeri and 0,83 ± 0,27 ind.m-² (July/13) to 10,31 ± 0,73 (November/12) for Uca maracoani. Sex ratio (male:female) was 1:1. Canonical correspondence analysis showed that abiotic factors can influence crab density, but do not limit species distribution. The average secondary production of the Uca sp. population ranged from 7.34 to 50.89 g PSLC m-1 y-1, for Uca thayeri ranged between 12.10 to 27.65 g PSLC m-1 y-1 and for Uca maracoani from 1.70 to 8.83 g PSLC m-1 y-1. The multiple regression shows the chlorophyll-a may influence Uca sp. (subgênero leptuca) productivity. For the Uca thayeri and Uca maracoani species not a single abiotic factor tested had an influence in productivity.
7

Dinâmica populacional e produção secundária de uca (Brachyura: Ocypodidae) no estuário dos rios Piraquê-açú e Piraquê-mirim, ES, Brasil / Population dynamics and secondary production of uca (Brachyura: Ocypodidae) in the estuary of Piraquê-açu and Piraquê-mirim rivers, ES, Brasil

Carolina Ortulan Pereira 05 September 2014 (has links)
Um estudo de distribuição temporal, proporção sexual e densidade de caranguejos do gênero Uca foi realizado no estuário dos rios Piraquê-Açu e Piraquê-Mirim, Santa Cruz, Espírito Santo, Brazil. A população de caranguejos presentes em 06 áreas dividias em 90 quadrados de 0.75 m² foi coletada mensalmente durante o período de Julho/2012 à Maio/2013. Os caranguejos foram coletados por escavação manual das tocas, identificados e sexados. A temperatura do ar e da água variou entre 21 a 27°C e 22 a 28°C, respectivamente, enquanto que a salinidade variou de 21 a 35. Um total de 5.391 espécimes foi coletado, sendo 2.823 machos e 2.568 fêmeas (sendo 40 ovadas). A densidade média para a população de Uca sp. (subgênero leptuca) variou de 18,01 ± 1,29 (Maio/13) a 62,22 ± 1,51 ind.m-² (Novembro/12), para Uca thayeri de 3,67 ± 0,63 (Julho/12) a 15,29 ± 1,44 ind.m-² (Janeiro/13) e para a população Uca maracoani de 0,83 ± 0,27 ind.m-² (Julho/13) a 10,31 ± 0,73 (Novembro/12). A proporção sexual foi 1:1 para cada espécie estudada. A análise de correspondência canônica indicou que houve influência dos fatores ambientais na densidade dos caranguejos. Entretanto, as variáveis abióticas não foram limitantes para a distribuição das espécies estudadas. A produção secundária para a população de Uca sp. (subgênero leptuca) variou de 7,34 para 50,89 g PSLC m-1 ano-1, para Uca thayeri de 12,10 para 27,65 g PSLC m-1 ano-1 e para a população Uca maracoani de 1,70 para 8,83 g PSLC m-1 ano-1. A análise de regressão multivariada indicou que para a espécie Uca sp. (subgênero leptuca) a quantidade clorofila-a está relacionada com a produtividade desta espécie e para as demais espécies nenhuma das variáveis abióticas estudadas estaria relacionada com sua produtividade. / The temporal distribution, sex ratio and density of the fiddler crab Uca spp. was studied in populations living in the Piraquê-Açu and Piraquê-Mirim estuaries, Santa Cruz, Espírito Santo State, Brazil. Ninety 0.75 m² in 06 areas were used to obtain monthly samples from July 2012 to May 2013. The crabs were collected manually through excavation of burrows, identified and sexed. Air and water temperatures varied from 21 to 27°C and 22 to 28°C, respectively, and the salinity from 21 to 35. A total of 5,391 fiddler crabs were collected, with 2,823 males and 2,568 females (40 ovigerous). The average densities for the three species found were 18,01 ± 1,29 (May/13) to 62,22 ± 1,51 ind.m-² (November/12), 3,67 ± 0,63 (July/12) to 15,29 ± 1,44 ind.m-² (January/13) for Uca thayeri and 0,83 ± 0,27 ind.m-² (July/13) to 10,31 ± 0,73 (November/12) for Uca maracoani. Sex ratio (male:female) was 1:1. Canonical correspondence analysis showed that abiotic factors can influence crab density, but do not limit species distribution. The average secondary production of the Uca sp. population ranged from 7.34 to 50.89 g PSLC m-1 y-1, for Uca thayeri ranged between 12.10 to 27.65 g PSLC m-1 y-1 and for Uca maracoani from 1.70 to 8.83 g PSLC m-1 y-1. The multiple regression shows the chlorophyll-a may influence Uca sp. (subgênero leptuca) productivity. For the Uca thayeri and Uca maracoani species not a single abiotic factor tested had an influence in productivity.
8

The Population Re-distribution and Transitional Trend of Urbanization Process in Kaohsiung Metropolitan Area

YANG, HUI-CHING 08 July 2009 (has links)
This study utilized historical population statistics data and related reports to investigate the population distribution and transition trend of Kaohsiung Main Urban Area. There were four purposes of this study; firstly to understand the current population distribution pattern of Kaohsiung Main Urban Area, secondly to investigate the change trend of Kaohsiung Main Urban Area in the past 36 years, thirdly using Kaohsiung Main Urban Area population data to verify the population density model and to examine the correspondence with the current society, and fourthly to explore the impact of the establishment of Kaohsiung Mass Rapid Transit System and Taiwan High Speed Rail to the transition and distribution of population in Kaohsiung Main Urban Area. This study employed the population statistical database from year 1972 to 2007, and divided the Kaohsiung metropolitan area into 32 sub-divisions. The population data was re-organized accordingly in order to perform the systematic analyses and exploration in making the understanding of the current population status and transition process. Furthermore, employing the population data of Kaohsiung metropolitan area, the validation of negative exponential model and quadratic exponential model, the population model proposed by Clark and Newling respectively 58 year ago, were performed to verify the applicability of the theories to modern society. In addition, this study also performed the exploration of population transition and distribution in Kaohsiung metropolitan area during the construction period of Kaohsiung Mass Rapid Transit System and Taiwan High Speed Rail and could be of reference to urban planning and development in the future. This study found that both Clark and Newling¡¦s population model still has high interpretation capability after 58 years later. The Kaohsiung metropolitan area population distribution model and trend forecast proposed by Ho in 1991 is still true. However, because of the slow down in overall development trend of Taiwan, the transition trend of Kaohsiung metropolitan also mitigated. Besides, due to the trend mitigation, the volcano peak phenomenon which was mentioned in the literature review will be postponed and expected to happen in year 2018.
9

Changing population distribution in Sweden : long term trends and contemporary tendencies

Håkansson, Johan January 2000 (has links)
The aim of the thesis is to describe and analyse the population redistribution in Sweden at different geographical levels from the beginning of the 19th century to the end of the 20th century. The analysis is approached in three different ways. First, the redistribution at different geographical levels is analysed (papers I and II). Second, the changing accessibility between people (interpersonal accessibility) is analysed from the beginning of the 19th century to the end of the 20th century (paper II). Third, the impacts of fertility, mortality, internal migration, international migration and geographical variations in age composition on population distribution are analysed for the last decades (papers I, III and IV). Measurements of concentration have been used in order to analyse the changing population distribution. For the analysis of changing interpersonal accessibility the average population within the daily reach has been calculated for different times. In order to analyse the impacts of fertility, mortality, migration and geographical variations in age composition the actual redistribution of the population is compared with the redistribution generated by a number of counterfactual scenarios. To analyse the impact of international migration the changing distribution of the population in different immigrant groups is compared to the distribution of the Swedish population. Some conclusions drawn from the thesis are: 1. There is no overall trend in the population redistribution towards either concentration or dispersion. The redistribution pattern depends on the time perspective and the geographical level chosen. The population has been both concentrated and dispersed since the beginning of the 19th century. This applies to all investigated geographical levels. In the five identified phases of the redistribution the most common pattern is that concentration and dispersion of the population exist simultaneously on different geographical levels. The total effect of the redistribution between 1810 and 1990 is that today the population is more dispersed at macro-regional level, while it is more concentrated at local and regional level. 2. Based on assumptions about the daily reach, an average person today has access to about 100 times more people locally compared with the beginning of the 19th century. The most important process for the increased accessibility has been the redistribution of the population. The process that has had the least impact is the assumed increase in daily reach. However the importance of the investigated processes changes over time. Since 1950 the increasing reach has been the most important process. However, the rate by which interpersonal accessibility increases has slowed down since 1950. 3. The main demographic factor behind the redistribution since 1970 is the geographical differences in age composition and its effects on the natural population change. It is demonstrated that this factor lies behind the trend towards increasing concentration in Sweden, while the impact of migration affects the fluctuations from this trend to a greater extent. 4. The study shows that immigration concentrates the population, while the internal migration during the 1970s and periodically during the 1980s dispersed the population. However during the 1990s the internal migration has had a concentrating effect on the spatial distribution of the population. / <p>Diss. (sammanfattning) Umeå : Umeå universitet, 2000, härtill 4 uppsatser</p> / digitalisering@umu
10

Rarity in boreal stream insects : patterns, causes and consequences /

Hoffsten, Per-Ola, January 2003 (has links)
Diss. (sammanfattning) Umeå : Univ., 2003. / Härtill 6 uppsatser.

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