Dissertations / Theses on the topic 'Spatial distribution'

This thesis is concerned with the cosmological evolution of quasars. I describe the construction of the Edinburgh Multicolour Survey from COSMOS scans of UK Schmidt photographic plates, taken in UBVRI wavebands at high galactic latitude in a contiguous area of 0.1 steradians (13 UK Schmidt fields). Two plates are taken close together in time in each waveband in each field so that spurious detections can be eliminated, and the errors on the measured magnitudes reduced. The raw COSMOS datasets were calibrated using photoelectric and CCD sequences in each waveband in each field. Systematic errors in the calibration due to "field effects" (variations in image size across each plate) are minimised by using the colours of the stars on each plate. Differences between the plates in each waveband are minimised. Differences in each waveband between fields are minimised by using the spatial distribution of stars in the survey, and requiring it to be uniform across the whole survey area. The calibration of the "worst" (as judged by the level of field effects) is tied in with that of the "best" plates. The final dataset is uniformly and accurately calibrated across the entire survey area. The systematic error in the COSMOS-measured magnitudes at B = 15 - 16 is 0.01m. The rms error at B = 17 - 18 (where most of the quasars are) is 0.09m. The Edinburgh Multicolour Survey was used to select a sample of bright UVX candidates. I then describe how follow-up spectroscopy was carried out to determine the nature of the candidates, and in the case of the quasars, to measure their redshifts. I compare the surface density of quasars found in this way to that measured by previous surveys, in particular the Palomar-Green Survey (Schmidt & Green 1983).

In this thesis I outline the different processes, operating at different scales, that influence the spatial distribution of mammals and review modelling approaches that have been used to represent these processes. I investigate the application of a selection of modelling approaches operating at different scales. A model based on the energetics and movements of individual foragers was developed to investigate population spacing patterns and applied to the red squirrel. At high food densities, small, similarly sized, non overlapping ranges were generated, whereas at low food densities ranges were larger, more overlapping and more variable in size. The model is a first step towards investigating the spacing patterns of ranging mammals. A model representing the positioning of dens was applied to predict the distribution of badger main setts. The model determined how many setts could be placed in suitable habitats while maintaining a pre-defined, minimum inter-sett distance. The representation of badger spacing behaviour and the utility of the approach is discussed. At a larger scale, a model based upon births and deaths within habitat patches and an explicit representation of dispersal between patches was used to assess plans to reintroduce the beaver. It predicted little or no population spread, in contrast to the application of a generic population viability analysis package that predicted rapid population spread. A difference in the representation of dispersal was identified as the most likely cause of the disparity. A general model based on these approaches was developed to investigate the interaction between dispersal and demographic processesing spatially explicit population models. The future of models to predict the spatial distribution of mammals is discussed in relation to issues of scale, management applications and modelling philosophies.

We consider a spherical swimmer that undergoes helical motion due to the existence of a propulsive torque which is not parallel to a propulsive force that pulls the cell through the fluid. In addition, the cell is bottom-heavy; the centre of gravity is offset from the centre of buoyancy which generates a gravitational torque. In the presence of shear, fluid viscosity generates a further torque. Because cells swim at low Reynolds number, these torques are balanced. This thesis extends the model developed in Bearon (2013) in two distinct directions. Firstly, we consider an extension to the case of a flow where the shear varies with position. We consider a downward flow in a vertical channel. We observe that depending on the parameters, cells may exhibit the classical accumulation towards the centre of the channel or display a new focussing away from the centre. Secondly, we develop the model to describe randomness associated with changes in cell orientation. This is done by developing a Fokker-Planck equation for helical swimmers in terms of Euler angles. The classical Fokker-Planck equation obtained by Pedley and Kessler (1992) is a special case of the equation derived in this thesis. To implement this model numerically as an individual based model, we derive the corresponding stochastic differential equations. The Fokker-Planck equation and stochastic differential equation are extended to examine the spatial-temporal distribution of helical swimmers. We explore in detail how the horizontal distribution of cells in channel flow evolves to an equilibrium state, and how the evolution depends on the model parameters. For non-helical swimmers, we compare the result of the model to the recent experiments of Croze et al (2017).

The entire thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file; a non-technical public abstract appears in the public.pdf file. Title from PDF of title page (University of Missouri--Columbia, viewed on March 24, 2010). Thesis advisor: Dr. Matthew Foulkes. Includes bibliographical references.

Measuring protein interactions in subcellular compartments is key to understanding cell signalling mechanisms, but quantitative analysis of these interactions in situ has remained a major challenge. This thesis presents a novel analysis technique, spatial intensity distribution analysis (SpIDA), which may be applied to images obtained using fluorescence microscopy. SpIDA measures fluorescent particle densities and oligomerization states within individual images. The method is based on fitting intensity histograms from single images with super-Poissonian distributions to obtain density maps of fluorescent molecules and their quantal brightness. Since distributions are acquired spatially rather than temporally, this analysis may be applied to both live and chemically fixed cells and tissue. The technique does not rely on spatial correlations, freeing it from biases due to subcellular compartmentalization and heterogeneity within tissue samples. First, we validated the analysis technique evaluating its limits and demonstrating how it can be used to obtain useful information from complex biological samples. Analysis of simulations and heterodimeric GABAB receptors in spinal cord samples shows that the approach yields accurate estimates over a broad range of densities. SpIDA is applicable to sampling within subcell areas and reveals the presence of monomers and multimers with single dye labeling. We show that the substance P receptor (NK-1r) almost exclusively forms homodimers on the membrane and is primarily monomeric in the cytoplasm of dorsal horn neurons. Triggering receptor internalization caused a measurable decrease in homodimer density on the membrane surface. Finally, using GFP-tagged receptor subunits, we show that SpIDA can resolve dynamic changes in receptor oligomerization in live cells and is applicable to detection of high order oligomerization states. We then compared SpIDA results with those obtained from fluorescence lifetime imaging, and used it to extract information on receptor tyrosine kinase (RTK) dimerization at the cell membrane in response to GPCR activation. We show that RTK dimerization can be used as an index of activation or transactivation and then characterize the level of transactivation of many RTK-GPCR pairs, with cell cultures and primary neuron cultures with endogenous levels of RTKs and GPCRs. Dose-response curves were obtained from which pharmalogical parameters can be compared for each GPCR studied. Our data demonstrates that by allowing for time and space quantification of heterogenous oligomeric states, SpIDA enables systematic quantitative mechanistic studies not only of RTK transactivation at the cell membrane, but also of other cell signaling processes involving changes in protein oligomerization, trafficking and activity in different subcellular localizations. Finally, we studied the changes in number of synaptic sites in the neurons of the dorsal horn of the spinal cord of rats after a peripheral nerve injury (PNI), which consists of our model for chronic pain. We show that, after the PNI, there is a general decrease in synaptic sites together with a scaling or increasing of some of the GABAA receptor subunits. This scaling of the GABAA receptors at the postsynaptic sites was replicated by incubating the histological sections in a brain derivative nerve factor. Furthermore, we use SpIDA to obtain stoichiometry information for the GABAA receptor subunits directly at the postsynaptic sites. In short, we observe a switch from receptors containing two alpha1 to receptors containing two alpha2 and alpha3. This general change in subunits will have a direct effect on the cell as it will have different effects on the cell membrane conductance in response to GABA. As demonstrated, the advantages and greater versatility of SpIDA over current techniques opens the door to a new level of quantification for studies of protein interactions in native tissue using standard fluorescence microscopy.
Measuring protein interactions in subcellular compartments is key to understanding cell signalling mechanisms, but quantitative analysis of these interactions in situ has remained a major challenge. This thesis presents a novel analysis technique, spatial intensity distribution analysis (SpIDA), which may be applied to images obtained using fluorescence microscopy. SpIDA measures fluorescent particle densities and oligomerization states within individual images. The method is based on fitting intensity histograms from single images with super-Poissonian distributions to obtain density maps of fluorescent molecules and their quantal brightness. Since distributions are acquired spatially rather than temporally, this analysis may be applied to both live and chemically fixed cells and tissue. The technique does not rely on spatial correlations, freeing it from biases due to subcellular compartmentalization and heterogeneity within tissue samples. First, we validated the analysis technique evaluating its limits and demonstrating how it can be used to obtain useful information from complex biological samples. Analysis of simulations and heterodimeric GABAB receptors in spinal cord samples shows that the approach yields accurate estimates over a broad range of densities. SpIDA is applicable to sampling within subcell areas and reveals the presence of monomers and multimers with single dye labeling. We show that the substance P receptor (NK-1r) almost exclusively forms homodimers on the membrane and is primarily monomeric in the cytoplasm of dorsal horn neurons. Triggering receptor internalization caused a measurable decrease in homodimer density on the membrane surface. Finally, using GFP-tagged receptor subunits, we show that SpIDA can resolve dynamic changes in receptor oligomerization in live cells and is applicable to detection of high order oligomerization states. We then compared SpIDA results with those obtained from fluorescence lifetime imaging, and used it to extract information on receptor tyrosine kinase (RTK) dimerization at the cell membrane in response to GPCR activation. We show that RTK dimerization can be used as an index of activation or transactivation and then characterize the level of transactivation of many RTK-GPCR pairs, with cell cultures and primary neuron cultures with endogenous levels of RTKs and GPCRs. Dose-response curves were obtained from which pharmalogical parameters can be compared for each GPCR studied. Our data demonstrates that by allowing for time and space quantification of heterogenous oligomeric states, SpIDA enables systematic quantitative mechanistic studies not only of RTK transactivation at the cell membrane, but also of other cell signaling processes involving changes in protein oligomerization, trafficking and activity in different subcellular localizations. Finally, we studied the changes in number of synaptic sites in the neurons of the dorsal horn of the spinal cord of rats after a peripheral nerve injury (PNI), which consists of our model for chronic pain. We show that, after the PNI, there is a general decrease in synaptic sites together with a scaling or increasing of some of the GABAA receptor subunits. This scaling of the GABAA receptors at the postsynaptic sites was replicated by incubating the histological sections in a brain derivative nerve factor. Furthermore, we use SpIDA to obtain stoichiometry information for the GABAA receptor subunits directly at the postsynaptic sites. In short, we observe a switch from receptors containing two alpha1 to receptors containing two alpha2 and alpha3. This general change in subunits will have a direct effect on the cell as it will have different effects on the cell membrane conductance in response to GABA. As demonstrated, the advantages and greater versatility of SpIDA over current techniques opens the door to a new level of quantification for studies of protein interactions in native tissue using standard fluorescence microscopy.

A limitation to engineering viable thick tissues (greater than a few hundred microns in thickness) has been the lack of vascularisation and a vascular supply. A key element in engineering such tissues is the generation of a supporting scaffold with a defined and wellcharacterized architecture. To date relatively little attention has been paid to characterization. The objective of this research was to develop well-characterized structures which will inform the rational design of the next generation of engineered thick tissues. Specifically, this research aimed to test combinations of various culturing environments, cell mono- and co-cultures, and scaffold architectures; develop improved imaging techniques and structural/spatial analytical methods to characterise porous polymer scaffolds; and use various spatial and morphological measures to quantify the relationships between scaffold geometric structure and cell distribution. Isotropic and anisotropic pore scaffolds were manufactured and then processed with nondestructive and destructive imaging methods, and characterised using image analysis methods to measure geometric parameters such as the degree of anisotropy/isotropy, porosity, and fractal parameters of pore and strut networks. Cells were introduced into scaffolds using a range of seeding methods and cultured in static and hydrodynamic environments. Quantification of the spatial cell distribution in cell-seeded scaffolds was done with first-order spatial statistics and fractal analysis. Findings comparing various destructive and non-destructive imaging methods found that cryotape cryohistology was the most accurate method for processing bare polymer scaffolds and eliminated histological artefacts common to other techniques. It was found with the various image analysis methods, surface and internal scaffold geometric architectures were strongly isotropic for porogen-fused porogen-leached scaffolds and anisotropic for TIPS scaffolds. For both isotropic and anisotropic pore scaffolds, collagen hydrogel infusion and droplet methods gave the highest cell seeding efficiencies (at 100% efficiency). The key finding in this study was that first-order spatial statistics and fractal analysis of cell distribution revealed that the geometric structure of the scaffolds had the strongest effect on spatial cell infiltration and distribution compared to the influence of culture environment or mono- and co-culture. Isotropic pore scaffolds had a higher level of cell distribution. Further work with optimizing the growth environment parameters, and utilizing collagen-infused cell-seeded scaffolds, may assist in achieving better cell growth. The work presented therefore provides the analytical basis for the rational design of tissue engineering scaffolds.

The temporal and spatial distribution of zooplankton within Brooklands Lagoon was recorded at 3 sites representing a range of salinities and hydrographic conditions. Plankton tows were made monthly for one year to estimate seasonal abundance and distribution of zooplankton species. Diel distribution patterns were investigated in February by sampling at 3-hour intervals for a 30-hour period. The 48 taxa identified within Brooklands Lagoon represent a depauperate fauna compared with the nearby Avon-Heathcote estuary and the Kaikoura coastal waters. Brooklands Lagoon had approximately one tenth of the zooplankton biomass found in the Avon-Heathcote estuary. Results of ordination analysis showed a succession of dominant groups: Acartia sp., Microcyclops sp., Camptocercus sp. and Miscegenus heretunga in the summer, followed by barnacle and copepod nauplii during the winter. Changes in zooplankton abundance and biomass were influenced more by river flow and the degree of seawater mixing, than season, chlorophyll a concentration or temperature. Daily zooplankton abundance patterns were strongly influenced by darkness, resulting from the combined effect of turbidity and diel period. Zooplankton were also abundant during the early morning while chlorophyll a concentrations were increasing. The meroplankton showed high biomass and abundances during daytime high tides. Gut analysis of larval mullet, Mugil cephalus showed a diet of cyclopoid copepods, ostracods and oligochaetes. The flatfish larvae, Rhombosolea plebia, revealed a high dependance on zooplankton, eating almost exclusively Miscegenus heretunga. This harpacticoid copepod had a temperature/salinity tolerance between 1.7->40ppt. salinity and <5-26°C over 24hours. This tolerance range is wider than the temperature and salinity ranges recorded in the lagoon.

Most quantitative ecological research on aquatic insects has addressed their immature stages. To understand their population dynamics, however, information on the adult stage is essential. This study aimed to obtain quantitative estimates of life cycle features, such as emergence, adult life span and fecundity, and to develop further the methods used. Field studies on adult insects revealed patterns in spatial and temporal distribution and the effect of land use on lateral dispersal. Finally, methods used to estimate dispersal and gene flow were discussed. Studies on Leuctra nigra demonstrated that their emergence is associated with the quantity of emergent substratum locally available. Female L. nigra can be classified as "immature" and "mature", based on the maturity of their eggs, and this was used as an approximate age marker in studies of adult survival and spatial distribution, and to improve estimates of emergence by excluding mature females from catches in pyramidal traps. A female biased sex ratio observed in L. nigra stemmed from a discrepancy in the life span of the genders, with shorter-lived males, combined with a change in habitat by the females. Most adult aquatic insects stayed close to the stream. Thus, half of the stoneflies travelled less than 18 m lateral to the channel and the dispersal ranges of caddis flies and female of mayflies were even shorter. Comparison of the movement along the stream with the lateral dispersal suggests that most dispersal is in the 'stream corridor' itself. Little distinction was found between lateral dispersal in different catchment land uses. It is still too early, however, to conclude that dispersal is unaffected by land use. Temporal and spatial distribution of leuctrid stoneflies differed among neighbouring catchments, with Leuctra inermis and L. nigra dominating in moorland and catchments managed for forestry, respectively. Both physiochemical factors and biological interactions could explain this distribution.

CoordenaÃÃo de AperfeÃoamento de Pessoal de NÃvel Superior
The growing demand for mobile telephony services and the advent of new technologies requires their continued expansion, in order to ensure safe, reliable and high quality to its users. As a direct consequence of this growth has been the need to increase the amount of Radio Base Stations (RBS) to be installed. This expansion may have visual impacts and damage to the health of the population in the surrounding areas of the base stations, seeking always the best practices for the deployment of base stations. This model is based on policies that allow for expansion of services of mobile networks and, at the same time reduce the visual impact of these facilities as well as damage to the health of the surrounding area of the population, in a complementary manner to the applicable legislation. This concern is motivated by the loss of quality of service presented by the mobile operators, due especially to the poor distribution of antenna signal distributors. The objective of this work is to make a diagnosis of the spatial distribution of Radio Base Stations in the city of Fortaleza, focusing on its normative aspects and the current management system and supervision of those cell sites. The technical and regulatory aspects of installations of base stations used in mobile telephony will be searched, focusing the case study in Fortaleza, in addition to identifying the public agencies responsible for managing the inspection of cell sites in this municipality, and establish their respective responsibilities. For this, the methodology used in the study is based on qualitative exploratory research, using the deductive method of approach, performing literature, through the consultation of books, periodicals, theses, dissertations and legislation available on mobile telephony in Brazil and world, its normative aspects and criteria for installation of base stations. Also we used a field survey, through structured interviews managers of public agencies responsible for the management and supervision of RBS. The study showed that Fortaleza has 843 base stations registered by ANATEL (2014), with 6.8 million active mobile lines. Research by the SEUMA showed, among other aspects, despite the demands of municipal law in 8914, supervising or is done randomly, or from accusations of \\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\"disagreement\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\" made by the people and that the body responsible not talk to one itself.
A crescente demanda pelos serviÃos mÃveis de telefonia e o advento de novas tecnologias exige sua contÃnua expansÃo, de modo a garantir serviÃos seguros, confiÃveis e de elevada qualidade aos seus usuÃrios. Como consequÃncia direta dessa expansÃo tem-se a necessidade do aumento na quantidade de EstaÃÃes RÃdio Base (ERB) a serem instaladas. Essa expansÃo pode apresentar impactos visuais e danos à saÃde da populaÃÃo nas Ãreas de entorno das ERBs, buscando-se sempre as melhores prÃticas para a implantaÃÃo das ERBs. Esse modelo baseia-se em diretrizes que permitem a expansÃo das redes dos serviÃos mÃveis e, ao mesmo tempo, reduzem os impactos visuais dessas instalaÃÃes assim como danos à saÃde da populaÃÃo da Ãrea de entorno, de modo complementar Ãs legislaÃÃes aplicÃveis. Tal preocupaÃÃo à motivada pela perda de qualidade do serviÃo apresentado pelas operadoras de telefonia mÃvel, devido, especialmente, à mà distribuiÃÃo das antenas distribuidoras de sinal. Assim, o objetivo deste trabalho à fazer um diagnÃstico da distribuiÃÃo espacial das EstaÃÃes de RÃdio Base no municÃpio de Fortaleza, enfocando seus aspectos normativos e o atual sistema de gerenciamento e fiscalizaÃÃo dessas ERBs. SerÃo pesquisados os aspectos tÃcnicos e normativos das instalaÃÃes das ERBs utilizadas na telefonia mÃvel, focando o estudo de caso no municÃpio de Fortaleza, alÃm de identificar os ÃrgÃos pÃblicos responsÃveis pelo gerenciamento da fiscalizaÃÃo das ERBs neste municÃpio e estabelecer as suas respectivas competÃncias. Para isso, a metodologia utilizada no trabalho à baseada na pesquisa exploratÃria qualitativa e quantitativa, fazendo uso do mÃtodo dedutivo de abordagem, realizando pesquisa bibliogrÃfica, atravÃs da consulta de livros, periÃdicos, teses, dissertaÃÃes e da legislaÃÃo disponÃvel sobre a telefonia mÃvel no Brasil e no mundo, seus aspectos normativos e critÃrios para instalaÃÃo das ERBs. TambÃm serà feita pesquisa de campo, atravÃs de entrevista estruturada aos gestores dos ÃrgÃos pÃblicos responsÃveis pelo gerenciamento e fiscalizaÃÃo das ERBs. O estudo mostrou que Fortaleza possui 843 ERBs cadastradas pela ANATEL (2014), com 6,8 milhÃes de linhas ativas de celulares. A investigaÃÃo junto à SEUMA mostrou, dentre outros aspectos que, apesar das exigÃncias da lei municipal no 8.914, a fiscalizaÃÃo ou à feita de forma aleatÃria, ou a partir de denÃncias de âdesconformidadeâ feitas pela populaÃÃo e que os ÃrgÃos responsÃveis nÃo dialogam entre si.

This thesis is concerned with the communication of information using auditory techniques. In particular, a music-based interface has been used to communicate the operation of a number of sorting algorithms to users. This auditory interface has been further enhanced by the creation of an auditory scene including a sound wall, which enables the auditory interface to utilise music parameters in conjunction with 2D/3D spatial distribution to communicate the essential processes in the algorithms. The sound wall has been constructed from a grid of measurements using a human head to create a spatial distribution. The algorithm designer can therefore communicate events using pitch, rhythm and timbre and associate these with particular positions in space. A number of experiments have been carried out to investigate the usefulness of music and the sound wall in communicating information relevant to the algorithms. Further, user understanding of the six algorithms has been tested. In all experiments the effects of previous musical experience has been allowed for. The results show that users can utilise musical parameters in understanding algorithms and that in all cases improvements have been observed using the sound wall. Different user performance was observed with different algorithms and it is concluded that certain types of information lend themselves more readily to communication through auditory interfaces than others. As a result of the experimental analysis, recommendations are given on how to improve the sound wall and user understanding by improved choice of the musical mappings.

Thesis (M.S.) -- University of Maryland, College Park, 2004.
Thesis research directed by: Agricultural and Resource Economics. Title from t.p. of PDF. Includes bibliographical references. Published by UMI Dissertation Services, Ann Arbor, Mich. Also available in paper.

Thesis (M.E.E.)--University of Delaware, 2006.
Principal faculty advisors: Kenneth E. Barner, Dept. of Electrical and Computer Engineering; and Mohsen Badiey, Dept. of Marine and Earth Studies. Includes bibliographical references.

Die selbständige, gerichtete Bewegung von biologischen Zellen ist eine der grundlegendsten und komplexesten Erscheinungen der Natur. In höher entwickelten Lebewesen spielt die Zellbewegung eine wichtige Rolle, z.B. bei der Entwicklung des Organismus, bei der Funktion des Immunsystems aber auch bei der Metastase von Krebszellen. Die physikalischen Prozesse die dieser Fähigkeit zugrunde liegen, sind im Fokus dieser Arbeit. Um besser zu verstehen welche Prozesse im Einzelnen und in welcher Kombination den Zellen erlauben sich gerichtet fortzubewegen, wurde in der vorliegenden Arbeit ein representatives Modellsystem von motilen Zellen untersucht. Fischkeratozyten bewegen sich in vitro regelmäßig und gleichförmig, relativ schnell über die Substratfläche, und stellen aus physikalischer Sicht eine optimierte, sich selbständig bewegende Polymermaschine dar. Um Kräfte in der Bewegungsebene der Zellen zu untersuchen, wurde in der vorliegenden Arbeit eine neuartige, auf dem Rasterkraftmikroskop (RKM) basierende Methode entwickelt. Zusätzlich wurden hochaufgelöste, mit dem Phasenkontrastmikroskop aufgenommene Bilderserien analysiert und die Geschwindigkeitsverteilung in der Zelle durch Korrelationsalgorithmen bestimmt. Die Struktur des Polymernetzwerkes wurde in mit Fluoreszenzfarbstoff markierten Zellen untersucht, und elastische Eigenschaften wurden mit rheologischen RKM-Messungen bestimmt. Traktionskraftmessungen an elastischen Substraten runden das umfassende Bild ab. Durch Veränderung der molekularen Strukturen mit verschiedenen Chemikalien, die unterschiedliche Prozesse im Gesamtsystem stören, konnte nun ein Phasenraum der Kraftgenerierungsprozesse untersucht und unterschiedliche Effekte verschiedenen Prozessen eindeutig zugeordnet werden. Es wurde somit erstmalig experimentell bewiesen, dass die Polymerisation von Aktin die treibende Kraft am vorderen Rand der Zelle ist. Darüber hinaus wurde das Verhalten des Kraftaufbaus mit einem Model beschrieben, das Aufschluss über die Funktionsweise der darunterliegenden Aktinpolymerstrukturens gibt. Desweiteren wurde in der Mitte der Zelle, zwischen vorderem Rand und Zellkörper, erstmalig eine rückwärtsgerichtete Kraft gemessen, die wichtig ist um ein Kräftegleichgewicht zu erstellen. Ein Model das auf entropischen Kräften im Polymersystem basiert, beschreibt diese kontraktilen Kräfte und ordnet sie der Depolymerisation von Aktin zu. Die Bewegung des Zellkörpers wiederum basiert auf dem Zusammenspiel dieser beiden Mechanismen, sowie der Kontraktion von Aktin und Aktinbündeln durch molekulare Motoren. Eine umfassendes Charakterisierung über verschiedene lokale Mechanismen und ihrer Wechselwirkungen konnte somit erstellt werden, und damit das Verständnis der Kraftgenerierung zur Zellbewegung vertieft.

Background Infection with Campylobacter is thought to account for about 5% - 14% of all food and waterborne diarrhoea cases worldwide. By international standards, New Zealand has extremely high rates of campylobacteriosis which are thought to be the highest reported rates worldwide. The incidence has been steadily increasing since 1980 (when the disease became notifiable), reaching a peak of cases in 2003 (396/100,000). Although different surveillance systems complicate international comparisons, New Zealand's particularly high rate still lacks a conclusive explanation. Aims This study investigates the geographical distribution of campylobacteriosis in New Zealand and the relative importance of factors assumed to be affecting the distribution of this disease, including those related to climate, landuse, water and food. The approach aims to explain why certain areas might increase the probability of becoming infected. Methodology A Geographical Information System (GIS) is used to visualise the disease rate, investigate potential disease clustering and identify outliers. Hierarchical regression, including the analysis of residuals, is applied to analyse the variables in their complex interrelation and to investigate whether there is statistical evidence explaining the geographical variation in campylobacteriosis. This study is undertaken at the territorial local authority level, as all required data are available at this spatial scale and covers the period 1997 to 2005. Results and conclusion There is a large geographical variation in campylobacteriosis across New Zealand, ranging from an average annual rate of 97/100,000 to 526/100,000 per territorial local authority (TLA). Generally, there is statistical evidence for global and local clustering of the disease rate. There are upper and lower outliers of campylobacteriosis in New Zealand; however, higher rates primarily appear in the South Island. The hierarchical modelling confirms statistical significance for some of the environmental and sociodemographic variables. The final model explains about 58% of the variation in campylobacteriosis, and the residuals reflect this variation relatively accurately in approximately 75% of all TLAs. Although the evaluation of the results is confronted with a number of challenges, it is concluded that socioeconomic and demographic factors are crucial factors in explaining the observed spatial patterns in the notification data.

Japan is located on the westem edge of the Pacific plate, in one of the most dynamic areas on Earth, with approximately 80 active volcanoes and considerable tectonic activity. The Japanese Nuclear Waste Management Organisation (NUMO) will construct a deep geological repository for high level nuclear waste somewhere in Japan. Potential hazard posed by a new volcanic event occurring and disrupting this facility during its operational lifetime need to be thoroughly assessed.

This research aims to develop Hierarchical Bayesian models for road accident counts that take account of the spatial dependency in the neighbouring areas or sites. The Poisson log-linear model is extended by introducing a second level of random variation that includes a conditional autoregressive (CAR) component. Both models for accidents at the area level and models for accidents on a road network are developed. Areal models are fitted using data for counties and districts in England covering two different periods and data for wards in the West Midlands region in 200l. Network models are fitted to link data for the MI motorway and to junction data for the city of Coventry. Results show that, in most cases, adding a spatial (CAR) component to conventional models produces better estimates of the expected number of accidents in an area or at a site. Signs of the coefficients for explanatory variables, including level of traffic and road characteristics, are consistent with expectation. Levels of the spatial effects in a CAR model reflect the relative influence of the unknown or unmeasurable explanatory variables on the expected number of accidents. Results from models at the local authority level in the 2000s show that spatial effects are positive in London boroughs and are negative in most metropolitan districts. For accidents at the ward level in the West Midlands, the performance of the CAR model is similar to that of the non-CAR model which includes log-normal random effects and metropolitan county effects. For models of accidents on the MI, several links are identified to have positive and fairly large spatial effects. For Coventry junction accidents, the CAR model does not perform better than the non-CAR model. Approaches to including temporal effects in spatial models when data cover two or more periods and jointly modelling different types of accidents are also proposed and examined. Two applications of the CAR models developed in this research are introduced. The first application is about predicting the number of accidents in a local authority in a new year based on previous years' data. One advantage of using the CAR model is that it produces more precise predictions than the non-CAR model. The second application of the CAR model is a new approach for site ranking. The sites selected by such a criterion are those with high risks caused by some unknown or unmeasured factors for instance, curvature or gradient of roads) which are spatially correlated. Further on-site investigation will be needed to identify such factors.

The way malaria parasites are transmitted in space will have an influence on their genetic relationships. It can be expected that parasites collected within close geographic distances of each other would be more closely related than those across large geographic distances. Further to this, because malaria transmission is focal and heterogeneous in space, then the genetic relatedness between malaria parasites in these foci of malaria transmission would be greater within tightly clustered regions. Thus, using the level of genetic relatedness of these parasites would reveal how they are transmitted not only within these foci but at different geographic settings. This knowledge would offer insight on how malaria control methods can be effectively disseminated. In field settings malaria infections are polyclonal and each of the clones represented within these infections occur at different proportions. With the aid of genetic markers such as single nucleotide polymorphisms (SNPs) or microsatellites, parasite clonal genotypes can be identified. In this study, the genetic markers of choice are SNPs. Using a method that can quantify these SNPs representing the different clones occurring at different proportions in an isolate, then each of the clonal genotypes can be determined. Microsatellites were also used as additional markers in the study. In this thesis, 1.Genetic markers (SNPs) across the P. falciparum genome were identified (Chapter 3); 2. PyrosequencingTM was validated as a technique that would enable the identification of each genetically distinct clone represented in an infection by assigning proportions to the SNPs representing each genetically distinct clone and enabling the identification of parasite clonal genotypes in every isolate analysed. This was validated using laboratory prepared clone mixtures of P. falciparum. In addition; the progeny from a cross derived from genetically characterised 3D7 and HB3 isolates was analysed in preparation for the analysis of the field isolates (Chapter 4). , 4. In Chapter 5, field isolates were tested and clonal genotypes identified using both SNPs and microsatellites. A detailed population genetic analysis was also performed and finally in Chapter 6, evidence for correlation between the genetic relationships of these parasites and geographic distance was investigated. The results from field isolates summarised in this thesis were from analysis of 54 isolates; 7 samples collected from Cameroon, 13 from Kenya and 34 from Mali. The data consists of 13 SNPs analysed by PyrosequencingTM and 8 microsatellites. 84 clonal genotypes were identified by both genetic markers from the analysed isolates. Analysis of both SNPs and microsatellites revealed that microsatellites were more informative than the SNPs based on the observed allelic richness and heterozygosity (genetic diversity) across all loci analysed. The overall FST value was 0.061 using SNPs and 0.043 by microsatellites analysis. These values were low but consistent with what is typically observed in African P falciparum populations. Finally, analyses of the combined data set revealed that no statistically significant levels of spatial autocorrelation existed within the studied parasite populations. However, there was evidence of within host mixed parasite infections exhibiting a high level of genetic relatedness compared to between host infecting clones.

Clusters of galaxies are among the most luminous X-ray sources in the sky. The X-ray emission originates from hot, diffuse intracluster gas which dominates the baryonic matter in the cluster. The distribution of the gas density follows that of the underlying (dark) mass potential. Consequently the cluster X-ray emission is concentrated towards the central core region of the cluster. By contrast, the galaxy distribution in clusters is more extended and, when studied in projection (e.g. on photographic plates), provides a less pronounced (optical) luminosity enhancement in the cluster core. Traditionally cluster samples have been developed by searching for projected galaxy enhancements in photographic or CCD surveys. However, for the reason outlined above, optical selection is an inferior method to X-ray selection. The work described in this thesis concerns the development of the SGP RASS Cluster Sample (SRCS) and its application to a quantitative study of large-scale structure in the Universe. The SRCS has been constructed from data acquired during the ROSAT All Sky Survey (RASS), where ROSAT is the German/UK/US X-ray satellite that was launched in 1990. The RASS, completed in 1992, constitutes the first all sky survey made with an imaging X-ray telescope. Approximately 50,000 X-ray emitting astronomical objects were detected during the RASS, of which roughly 10% are clusters of galaxies. Until the advent of the RASS, it was not possible to make large X-ray selected samples of clusters because the existing X-ray data either suffered from poor spatial resolution or did not provide homogeneous coverage over a large enough area of the sky. The prospect, therefore, of samples of ˜ 1000 ROSAT detected X-ray clusters is very exciting. The astrophysical and cosmological problems that can be addressed with such samples are manifold.

The spatial segregation is a feature of metropolitan partners; in the case of Lima it is related to income level and social factors. In this case, the study of socio-spatial segregation from a geographic viewpoint is advantageous and timely. This is because of geography has an undiscovered potential to articulate the basis for a social and human inclusion based on knowledge and apprehension of space, in a world marked and «segregated» by incontrovertible geographical andsocial differences. In turn it breaks up old paradigms in Latin American urban research, whichis based on the acceptance of «concerted» truths without proper scientific experimentation.
La segregación espacial es una característica de las metrópolis asociada en el caso de Lima conel nivel de ingresos y factores sociales. En este caso el estudio de la segregación socioespacial desde una visión geográfica resulta ventajoso y oportuno. Debido a que la geografía posee una potencialidad no descubierta de articular las bases para una inclusión social y humana a partir del conocimiento y aprehensión del espacio, en un mundo marcado y «segregado» por incontrastables diferencias geográficas y sociales. A su vez se plantea romper con viejos paradigmas en la investigación urbana latinoamericana, la cual se basa en la aceptación de verdades aceptadas «concertadamente» sin una apropiada experimentación científica.

Determination of the spatial distribution and quantification of concentration of pure beta- and photon-emitting radionuclides in absorbing media by external measurements is the subject of this study. Measurements of radiation and the operation of radiation detectors are based on the radiation interactions with matter and the theory governing these interactions has been discussed. Various techniques for localising pure beta- and photon-emitting radionuclides situated inside attenuating media have been suggested on a theoretical basis, and have been experimentally shown to work successfully. Most of the work is on single photon emission computed tomography (SPECT). The theory of mathematical reconstruction of a two dimensional distribution from its projections is discussed and reconstruction techniques and their relative merits and demerits have been reviewed. SPECT seeks the determination of absolute regional radionuclide concentrations as a function of time. A SPECT system has been developed by modifying an existing transmission CT scanner and the reconstruction algorithms. The performance of the SPECT system has been tested for a number of point sources and various extended sources in gas, liquid and solid forms. The SPECT scanner in its present design is capable of performing in both the transmission and emission modes. The characteristics of the SPECT scanner, including the detector efficiency, spatial resolution and the effect of collimator size, have been studied experimentally. The major problems faced by SPECT include the solid angle effect, which influences the collection efficiency, in scattered radiation, and attenuation of photons inside the surrounding medium. These problems together with their various possible solutions have been discussed in detail. Methods for compensation for solid angle variation, in scattered radiation and photon attenuation have been devised and used successfully to compensate the projection data.

Vietnam, a tropical country in Southeast Asia, has been dengue endemic since 1958. Dengue poses a major public health concern and economic burden to Vietnam, with average incidence of more than one hundred thousand cases, annually. Dengue epidemiology is complex and a result of interactions between the host, the virus, the vector and environmental factors. This thesis sought to investigate and define the spatial and temporal transmission patterns of dengue in order to support planning allocation of resources to better control and predict the seasonal epidemics. Increases in reported dengue incidence over the past decade suggest that dengue is an emerging problem in Hanoi, the capital of Vietnam. We found that districts in the central, highly urbanized area of Hanoi are at highest risk of dengue (Standardized Morbidity Ratio >3). Rainfall and temperature correlated positively with dengue incidence, while wind velocity correlated negatively. In Ho Chi Minh City (HCMC), the per capita incidence of dengue was lower than in most southern provinces and annual epidemics occurred 1-3 months later than elsewhere. Both the timing and the magnitude of annual epidemics were significantly more correlated in districts at closer proximity, suggesting local drivers operating at a scale of 50-100km. Using a simple linear model we showed that dengue incidence during the dry season accounted for 63% of variability in rainy season epidemic magnitude. Finally, we examined spatial patterns of case and serotypes distribution of dengue in HCMC in comparison to Bangkok, Thailand. We found that annual case numbers were highly consistent across the two cities (correlation of 0.77,95% Cl 0.74-0.79) as was the annual force of infection (correlation of 0.57, 95% Cl 0.46-0.68). Serotypes were far less similar with serotype-specific correlations ranging from 0.65 for DENV1 to -0.14 for DENV4. Significant spatial clustering of serotypes was observed in HCMC at distances <500m, similar to observations from Bangkok. These data suggest similar overall mechanisms determine the epidemiology of dengue in these two major urban centres. Collectively the findings in this thesis might aid the targeting of vector-control interventions, the planning for dengue vaccine implementation and/or epidemic prediction.

This thesis concerns robust load allocation in communication networks. The main goal of this work is to avoid the situation in which the failure of a node (or nodes) causes a cascade of failures through an entire network, with a sequence of healthy nodes becoming overloaded and failing from picking up the slack from previously failed nodes. The network should remain functional even after some of the nodes have failed. In the dissertation we present a new methodology for dynamically distributing the load across a network so as to avoid the overloading of any of the networks' nodes. A numerical solution is proposed to solve this model and build a simulation tool. This numerical method adjusts the classic explicit form of Runge-Kutta 4th order in order to integrate graph principles and produce synchronized numerical solutions for each network element. Unlike most solutions in the literature, as for example, Motter et al. [2002], Motter and Adilson [2004], Liang et al. [2004], Schafer et al. [2006], Wang and Kim [2007] and Pinget et al. [2007] our methodology is generic in the sense that it works on any network topology. This means not only that it is applicable to a large range of networks, but also that it continues to be relevant after failure has destroyed part of a network, thereby changing the topology. In particular, geographical catastrophes can be of both random and intended types, taking place within a heterogeneous physical environment, on a civil (populated) area. Unlike most fault methodologies in the literature our methodology is generic in the sense that it simulates real-world geographic failure propagation towards any type of network which can be embedded to a two dimenional metric system [Chen and He, 2004], Liu et al. [2000], Callaway et al. [2000], Albert and Barabasi [2000]. It describes how physical one dimensional catastrophic waves spread in heterogeneous environments and how built-in resilience, within each network element determines its percentage of damage. We have tested our system on various randomly generated graphs with faults injected according to a model we have developed that simulates real-world geographic failure propagation. We present results from our dynamic traffic distribution methodology applied to networks, which have been either under attack or not. Throughout our case studies we prove that as soon as the topology is assigned the appropriate resources comparing to the load that it is to serve, our methodology successfully redistributes the load across the network and prevents a potential cascade failure. We either prevent the propagation of cascading failures or suggest recovery strategies after an unavoidable failure. Therefore, our methodology is instrumental in designing and testing reliable and robust networks.

The nature of spatial distributions of geological variables such as ore grades is of primary concern when modelling ore bodies and mineral resources. The aim of any mineral resource evaluation process is to determine the location, extent, volume and average grade of that resource by a trade off between maximum confidence in the results and minimum sampling effort. The principal aim of almost every geostatistical modelling process is to predict the spatial variation of one or more geological variables in order to estimate values of those variables at locations that have not been sampled. From the spatial analysis of these variables, in conjunction with the physical geology of the region of interest, the location, extent and volume, or series of discrete volumes, whose average ore grade exceeds a specific ore grade cut off value determined' by economic parameters can be determined, Of interest are not only the volume and average grade of the material but also the degree of uncertainty associated with each of these. Geostatistics currently provides many methods of assessing spatial variability. Fractal dimensions also give us a measure of spatial variability and have been found to model many natural phenomenon successfully (Mandelbrot 1983, Burrough 1981), but until now fractal modelling techniques have not been able to match the versatility and accuracy of geostatistical methods. Fractal ideas and use of the fractal dimension may in certain cases provide a better understanding of the way in which spatial variability manifests itself in geostatistical situations. This research will propose and investigate a new application of fractal simulation methods to spatial variability and spatial interpolation techniques as they relate to ore body modelling. The results show some advantages over existing techniques of geostatistical simulation.

The Janzen-Connell hypothesis proposes that species-specific enemies promote species coexistence through distance- and density-dependent survival of offspring near conspecific adults. I tested this hypothesis experimentally by transplanting juvenile-sized fragments of two species of brooding corals varying distances from conspecific adults, and observationally by assessing the spatial distribution of those two species in the field. Small fragments (as proxies for ?6 month old juveniles) of Pocillopora damicornis and Seriatopora hystrix were transplanted 3, 12, 24 and 182 cm upstream and downstream (relative to the prevailing current) of conspecific adults and their survivorship and condition (bitten off, overgrown by algae, or bleached) checked every 1-2 d. I also characterized the spatial distribution of P. damicornis and S. hystrix within replicated plots on three Fijian reef flats and measured densities of small colonies within 2 m of larger colonies of each species. Contrary to the Janzen-Connell hypothesis, juvenile-sized transplants exhibited no differences in survivorship as a function of distance from adult P. damicornis or S. hystrix and P. damicornis and S. hystrix were aggregated rather than overdispersed on natural reefs. Survival unaffected by distance from focal colonies as well as certain recruitment processes could generate the observed aggregation. I did observe predation of P. damicornis that was spatially patchy and temporally persistent due to feeding by the territorial triggerfish Balistapus undulatus. This patchy predation did not occur for S. hystrix. Thus, I found no support for the Janzen-Connell hypothesis, but did document hot-spots of species-specific corallivory that could create variable selective regimes on an otherwise more uniform environment, and help maintain the high diversity of corals typical of Indo-Pacific reefs.

Les bactéries ont colonisé toutes les niches écologiques de la planète. Plus précisément, les sols sont l’hôte de la plus grande biodiversité terrestre, la faune microbienne. Cette grande diversité de bactéries et leur relative ubiquité rendent difficile l’identification des variables contrôlant la distribution spatiale des bactéries vivant dans le sol. Comme les bactéries du sol jouent un rôle important dans les grands cycles biogéochimiques globaux, il est important de mieux comprendre les variables qui peuvent influencer la composition bactérienne des sols. Dans cette thèse, nous émettons l'hypothèse que l'hétérogénéité de la composition de la communauté bactérienne apparaît à la même échelle spatiale que l'hétérogénéité des propriétés physico-chimiques du sol. Afin de comprendre la relation entre la composition bactérienne des sols (à l’échelle d’une carotte de sol jusqu’à l’échelle d’une région entière du nord de la France) et les paramètres physico-chimiques du sol à différentes échelles spatiales, nous allons utiliser une approche intégrant des données issues d’analyses SIG (Système d’Information Géographique), d’analyses physico-chimiques du sol et d’analyses des communautés bactériennes du sol. A travers une suite de trois expérimentations, nous allons répondre à trois questions: Est-ce qu’une pression environnementale uniforme à une plus grande échelle (cm) peut atténuer l’hétérogénéité microbienne à micro-échelle? Est-ce que les variables ayant une distribution spatiale suivant un gradient géographique sont des variables structurant fortement la distribution spatiale des bactéries à l’échelle de ce même gradient? Est-ce que certains bio-indicateurs à grandes échelles peuvent intégrer des groupes de variables pour modéliser la distribution des bactéries pour une région entière ?
The bacteria have colonized all the niches of the planet. Specifically, soils are home of the largest terrestrial biodiversity, microbial fauna. This great diversity of bacteria and their relative ubiquity make it difficult to idendified variables driving the spatial distribution of bacteria living in the soil. As soil bacteria play a significant role in the main global biogeochemical cycles, it is important to better understand the variables that can influence bacterial composition of soils. In this thesis, we hypothesize that heterogeneity of the bacterial community composition appears at the same scale level as the heterogeneity of soil physicochemical properties. In order to understand the relationship of bacterial composition of soils (from core experiment to field study in large region in the northern France) and soil factors at different spatial scales, we will use an approach coupling GIS tools, soil physico-chemical analysis and 16S rRNA gene NGS. With Three set of experiment we will answer three questions: Can a uniform environmental pressure at a larger scale (cm) overcome microbial micro-scale heterogeneity? Are geographical gradients strong drivers of the microbial community structure at the scale of the gradient? Do large-scale geographical features that integrate groups of parameters model the differences in microbial community structure for an entire region?

The theme of this study is spatial mismatch, a concept that gave rise to an ever-expanding body of research concerned with how and why residential and employment distributions have shifted within cities and across metropolitan areas. The concept grew out of John F. Kain's research on how racial discrimination and segregation affects the spatial patterns of people/subgroups and jobs in the postwar American urban environment. Specifically, "Housing Segregation" posits that housing-market discrimination is at the root of increased unemployment among inner-city, nonwhite workers; concurrently, the pace and volume of decentralization (of residents and employment) from central-cities reinforces low-income, overwhelmingly African-American isolation and immobility. This study contributes to the New Orleans literature by providing a pre- and post-Katrina snapshot of spatial mismatch. The analysis addresses research questions aimed at gauging the extent to which mismatch and job-isolation have changed for poor workers in the New Orleans metro area since Hurricane Katrina.

Chercher sa nourriture s'avère coûteux et potentiellement exigeant cognitivement, notamment pour des animaux comme les primates, vivant dans un environnement difficilement prévisible. Les fruits étant une ressource éphémère, un régime alimentaire frugivore implique des capacités cognitives élevées. Cette étude comparative s'intéresse aux différentes stratégies mises en place lors du fourragement chez trois espèces de primates (Macaca tonkeana=5, M. fascicularis=3 and Sapajus sp.=6) vivant dans des parcs boisés, au Centre de Primatologie de l'Université de Strasbourg. Ces conditions d'hébergement en semi-liberté nous ont permis de manipuler l'environnement afin de simuler la répartition saisonnière spatio-temporelle des fruits en milieu naturel. Nous avons notamment fait varier la disponibilité de différents fruits chaque semaine avec un rythme saisonnier d'un mois, répété pendant quatre mois. Notre protocole expérimental vise à évaluer le poids des variables Où (localisation, tâche « Fourragement Spatial »), Quoi (distribution, tâches « Groupé vs. Dispersé » et qualité, tâche « Groupé vs. Qualité »), et Quand (disponibilité) sur les décisions individuelles lors de la recherche de nourriture. Nous avons utilisé 42 boîtes à ouverture télécommandée, fixées sur des arbres de l'enclos des singes, dans lesquelles nous avons placé des fruits. Ce dispositif a permis de tester les sujets individuellement dans leur groupe social. Pour chaque essai, nous avons enregistré les trajectoires des sujets, l'ordre des boîtes visitées et la présence de congénères. Dans la tâche « Fourragement Spatial », nous avons comparé les trajectoires observées des essais dans lesquels les sujets ont visité toutes les boites (Ntot=77) avec des trajectoires simulées pour trois stratégies : optimale, de proche en proche, ou aléatoire. Aucune espèce n'a suivi une stratégie aléatoire, les capucins suivent fréquemment une trajectoire optimale, les macaques fascicularis suivent davantage une stratégie de proche en proche alors que les Tonkeans suivent les deux stratégies avec des fréquences similaires. Toutes les espèces ont adopté soit une stratégie globale (trajet optimal) soit une stratégie locale (boite la plus proche) afin de fourrager efficacement. Les expériences de la tâche « Groupé vs. Dispersé » proposent aux animaux de choisir parmi des boîtes dont la répartition spatiale forme deux patchs de nourriture de six boites chacun, l'un groupé, l'autre dispersé. Nous avons testé l'effet de cette distribution spatiale en utilisant les mêmes fruits dans les deux patchs (Nobs=2477). Nos résultats indiquent une préférence pour la distribution groupée (vs. dispersée) chez les trois espèces. Nous avons également testé l'effet de la qualité de la nourriture (tâche « Groupé vs. Qualité ») en proposant deux fruits différents disponibles en même temps, le préféré dans la distribution dispersée vs. le moins préféré dans la distribution groupée (Nobs=2546). Les trois espèces ont continué de choisir préférentiellement la distribution groupée, mais les Tonkeans dans une moindre mesure que les capucins, ce qui indique que la qualité influence également leurs choix. Les Tonkeans ont aussi montré des déplacements plus directs. Enfin, pour la composante Quand, les sujets ont bien adapté leur fourragement à la séquence temporelle de la disponibilité alimentaire, répétée quatre fois, mais des hypothèses alternatives peuvent expliquer ces résultats (e.g. capacité à reconnaitre les boîtes disponibles). Cette étude montre que toutes les espèces utilisent des stratégies de fourragement efficaces. Cependant, contrairement aux omnivores, les frugivores ont davantage pris en compte leurs préférences alimentaires et ont montré des déplacements plus directs vers les sites alimentaires. Cette étude souligne que les contraintes écologiques des espèces peuvent affecter l'évolution des capacités cognitives et, plus généralement, des comportements
Foraging can be a challenging activity, especially for animals like primates living in seasonal environments characterised by not fairly predictable food availability. Since fruit is an ephemeral resource, a frugivorous diet is associated to brain size and high cognitive abilities. This comparative study aims to investigate the spatial foraging strategies of three primate species (Macaca tonkeana=5 individuals, M. fascicularis=3 and Sapajus sp.=6) having different degree of frugivory and living in semi-free ranging conditions at the Primate Centre of Strasbourg University. The experimental protocol aims to assess the relative weight of Where (food location, Spatial Foraging Task), Where vs. What (food distribution, Clumped vs. Scattered Tasks and quality, Clumped vs. Quality Task) and When (food temporal availability) variables on the individual foraging decisions. Forty-two boxes were fixed on trees in the outdoor area and were lockable via a remote-control system to individually test subjects in their social group. Each week, a subset of boxes was filled with one/two appealing fruit types; a seasonal pace of one month was repeated for four months to mimic the seasonality of wild fruit. We recorded subjects' trajectories, the order of visited boxes and the presence of other individuals. In the Spatial Foraging Task, considering the trials in which subjects visited all six baited boxes (Tonkeans Ntrials=35, long-tailed macaques Ntrials=31, capuchins Ntrials=11), we compared the observed routes to simulated routes under three strategies: optimal route, nearest neighbour rule, random route. None of the species choose random routes, suggesting that they relied on spatial memory to visit food sites. Capuchins optimized more their travels than long-tailed macaques, which followed mainly a nearest neighbour strategy, while Tonkeans used both strategies at similar frequency. All study species used a global (optimal path) or local strategy (nearest-neighbour rule) to forage efficiently. In the Clumped vs. Scattered Tasks, we tested how the food distribution influences primate spatial foraging. In the Clumped vs. Scattered Task 1, 12 boxes were baited with the same fruit type, six boxes in a circular clumped distribution and other six in a scattered circle. The Task 2 provided a similarly preferred fruit in the same two circular configurations but with opposite reciprocal spatial positions in terms of the side of the outdoor area. All study species (Nvisited boxes=2477) visited at first significantly more the clumped distribution. In the Clumped vs. Quality Task, we assessed the relative impact of food preference versus food distribution: boxes had the similar spatial configuration of the Clumped vs. Scattered Task 1 but the scattered distribution was filled with the most favourite fruit and the clumped one with the least preferred fruit. All species (Nvisited boxes=2546) showed again a preference for visiting first the boxes of the clumped distribution, but the most frugivorous species, Tonkeans, showed a less strong preference compared to the least frugivorous, the capuchins. The higher was the frugivory degree of the species, the higher were the goal-directed travels. Lastly, to investigate if primates developed a temporal knowledge of fruit availability, we investigated if they correctly remembered food spatio-temporal availability: primates visited each month between 79%-98% of baited boxes/tot boxes visited, even if this positive result could be explained by alternative hypothesis (e.g. ability in detecting the available boxes). All primate species maximised foraging efficiency, avoiding random walks. However, frugivorous species took food preference into account in their decisions and showed significantly more goal-directed movement. This study underlines how species feeding ecology may affect the evolution of their abstract mental abilities and more in general, their behaviour

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/).

Grid-type flight patterns at an altitude of 30 m were executed in the summer of 1991 by the Canadian Twin Otter flux research aircraft over a 15 km x 16.5 km agricultural area, as part of the San Joaquin Valley Air Quality Study/California Ozone Deposition Experiment (SJVAQS/CODE). Fast-response on board sensors for turbulence, temperature and gas concentrations permitted the spatial mapping of fluxes of momentum, sensible heat, moisture, CO$ sb2$ and ozone. Flux maps were produced in the form of GIS-interpolated 1 km averages, and in the discrete form of those coherent structures of the turbulent process, intermittent in time and space, which dominate the exchange of scalars between the ground and the atmosphere. The magnitude of surface-related mesoscale contributions to the flux was also quantified. Flux observations were compared against radiometrically observed surface temperatures and vegetation indices (NDVI), observed from aircraft and satellite (NOAA AVHRR), and surface characteristics from ground surveys.
Flux maps showed the expected correspondence between greenness, evapo(trans)ration (ET) and CO$ sb2$ exchange. Discrepancies between ozone flux maps and maps of greenness, ET or CO$ sb2$ were more pronounced than would be consistent with the hypothesis of stomatal control of ozone uptake. More insight into control mechanisms on ozone exchange is gained by an examination of the spatial coincidence between transporting structures for the various scalars (heat, moisture, CO$ sb2$ and ozone), through the Jaccard coefficient of co-location (J), which showed a lower value ($ rm0.3