Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 4 de 4
Filtrar
Mais filtros

Bases de dados
País/Região como assunto
Tipo de documento
Assunto da revista
Intervalo de ano de publicação
1.
Appl Spat Anal Policy ; 15(1): 95-116, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35222737

RESUMO

Contextual poverty refers to high proportions of people with a low income in a certain (residential) space, and it can affect individual socioeconomic outcomes as well as decisions to move into or out of the neighbourhood. Contextual poverty is a multiscale phenomenon: Poverty levels at the regional scale reflect regional economic development, while meso-scale concentrations of poverty within cities are related to city-specific social, economic and housing characteristics. Within cities, poverty can also concentrate at micro spatial scales, which are often neglected, largely due to a lack of data. Exposure to poverty at lower spatial scales, such as housing blocks and streets, is important because it can influence individuals through social mechanisms such as role models or social networks. This paper is based on the premise that sociospatial context is necessarily multiscalar, and therefore contextual poverty is a multiscale problem which can be better understood through the inequality within and between places at different spatial scales. The question is how to compare different spatial contexts if we know that they include various spatial scales. Our measure of contextual poverty embraces 101 spatial scales and compares different locations within and between municipalities in the Netherlands. We found that the national inequality primarily came from the concentrations of poverty in areas of a few kilometres, located in cities, which have different spatial patterns of contextual poverty, such as multicentre, core-periphery and east-west. In addition to the inequality between municipalities, there are considerable within-municipality inequalities, particularly among micro-areas of a few hundred metres.

2.
Sci Total Environ ; 540: 410-7, 2016 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-26216478

RESUMO

In this study, we aimed to assess the population status of bleak (Alburnus spp.) over the Western Balkan Peninsula in terms of its sustainable use. A second objective was to determine key factors important for fishery management planning. Two different basins, continental (the Danube Basin and the Sava River sub-basin) and marine (the Adriatic and the Aegean Sea Basins) were examined. A sustainability assessment and factor analysis were conducted using the adjusted ESHIPPOfishing model, extended with additional socio-economic sub-elements, and the categorical principal components analysis (CATPCA), respectively. The results of the assessment revealed the bleak populations in the Danube Basin and the Sava River sub-basin to be highly sustainable. The population characteristics with abiotic and biotic factors were responsible for this status, while the influence of socio-economic factors was insignificant. The sustainability status of the bleak populations of the Mediterranean basin varied, with the populations from Ohrid and Skadar Lakes showing a high and those from Prespa and Dojran Lakes a medium status. Socio-economic factors with traditional fishing were the most important for the Mediterranean bleak populations.


Assuntos
Conservação dos Recursos Naturais/métodos , Cyprinidae/crescimento & desenvolvimento , Pesqueiros/métodos , Animais , Península Balcânica , Monitoramento Ambiental , Pesqueiros/estatística & dados numéricos , Variação Genética , Lagos , Filogenia
3.
Sci Total Environ ; 497-498: 642-650, 2014 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-25170830

RESUMO

The permanent increase in the exploitation of commercial fish species has led to the need for developing practical and effective tools for the sustainability assessment and management of the target fish populations. The aim of this study was to formulate an ESHIPPOfishing model which would provide a reliable assessment of commercial fish population sustainability and indicate the conservation priorities. The existing ESHIPPO model was modified by introducing a new Index of local sustainability of fish populations (ILSFP) which enables the selection of "keystone populations" and "keystone habitats/ecosystems" within the basin being investigated. We employed a self-organizing map (SOM) in order to visualize the spatial distribution of the keystone populations and keystone habitats/ecosystems for each fish species. Based on the ILSFP values, environmental specialization (ES) of a fish species and local environmental factors (HIPPO factors), the model estimates the degree of sustainability (DS) of commercial fish populations in the freshwater ecosystems of the western Balkan Peninsula. The results indicate a low degree of sustainability for the majority of commercial fish species of the Middle Danube Basin, especially Acipenser ruthenus and Hucho hucho. The ESHIPPOfishing model presents a cost effective conservation approach, formulated to be applicable to any kind of river basin. The application of the ESHIPPOfishing model provides a comprehensive insight into the viability of target fish populations, which would not only further improve the selection of conservation priorities, but also facilitate the management of aquatic ecosystems.


Assuntos
Conservação dos Recursos Naturais/métodos , Pesqueiros/métodos , Peixes , Animais , Ecossistema , Pesqueiros/estatística & dados numéricos , Modelos Teóricos , Dinâmica Populacional , Rios
4.
Chemistry ; 15(44): 11853-66, 2009 Nov 09.
Artigo em Inglês | MEDLINE | ID: mdl-19844929

RESUMO

We have explored the utility, strength, and limitation of through-space exciton-coupled circular dichroism in determination of the secondary structure of optically active chromophoric nanoarrays using the example of end-capped porphyrin- and metalloporphyrin-oligodeoxynucleotide conjugates. We put special emphasis on the explanation of the origin and significance of the distinctive multiple bands in the CD spectra (trisignate and tetrasignate CD bands). Such CD profiles are often observed in chiral aggregates or multichromophoric arrays but have never before been studied in detail. We found that variation of temperature and ionic strength has a profound effect on the geometry of the porphyrin-DNA conjugates and thus the nature of electronic interactions. At lower temperatures and in the absence of NaCl all three 5'-DNA-porphyrin conjugates display negative bisignate CD exciton couplets of variable intensity in the Soret region resulting from through-space interaction between the electric transition dipole moments of the two end-capped porphyrins. As the temperature is raised these exciton couplets are transformed into single positive bands originating from the porphyrin-single-strand DNA interactions. At higher ionic strengths and low temperatures, multisignate CD bands are observed in the porphyrin Soret region. These CD signature bands originate from a combination of intermolecular, end-to-end porphyrin-porphyrin stacking between duplexes and porphyrin-DNA interactions. The intermolecular aggregation was confirmed by fluorescence and absorption spectroscopy and resonance light scattering. DeVoe theoretical CD calculations, in conjunction with molecular dynamics simulations and Monte Carlo conformational searches, were used to mimic the observed bisignate exciton-coupled CD spectra as well as multiple CD bands. Calculations correctly predicted the sign and shape of the experimentally observed CD spectra. These studies reveal that the exciton-coupled circular dichroism is a very useful technique for the determination of the structure of optically active arrays.


Assuntos
DNA/química , Porfirinas/química , Absorção , Sequência de Bases , Dicroísmo Circular , Cobre/química , DNA/genética , Dimerização , Luz , Metaloporfirinas/química , Simulação de Dinâmica Molecular , Método de Monte Carlo , Conformação de Ácido Nucleico , Concentração Osmolar , Espalhamento de Radiação , Cloreto de Sódio/química , Espectrometria de Fluorescência , Estereoisomerismo , Zinco/química
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA