Selecting a global optimization method to estimate the oceanic particle cycling rate constants

The objective is to select an inverse method to estimate the parameters of a dynamical model of the oceanic particle cycling from in situ data. Estimating the parameters of a dynamical model is a nonlinear inverse problem, even in the case of linear dynamics. Generally, biogeochemical models are characterized by complex nonlinear dynamics and by a high sensitivity to their parameters. This makes the parameter estimation problem strongly nonlinear. We show that an approach based on a linearization around an a priori solution and on a gradient descent method is not appropriate given the complexity of the related cost functions and our poor a priori knowledge of the parameters. Global Optimization Algorithms (GOAs) appear as better candidates. We present a comparison of a deterministic (TRUST), and two stochastic (simulated annealing and genetic algorithm) GOAs. From an exact model integration, a synthetic data set is generated which mimics the space-time sampling of a reference campaign. Simulated optimizations of two to the eight model parameters are performed. The parameter realistic ranges of values are the only available a priori information. The results and the behavior of the GOAs are analyzed in details. The three GOAs can recover at least two parameters. However, the gradient requirement of deterministic methods proves a serious drawback. Moreover, the complexity of the TRUST makes the estimation of more than two parameters hardly conceivable. The genetic algorithm quickly converges toward the eight parameter solution, whereas the simulated annealing is trapped by a local minimum. Generally, the genetic algorithm is less computationally expensive, swifter to converge, and has more robust procedural parameters than the simulated annealing

The Network of French Legal Codes

We propose an analysis of the codified Law of France as a structured system. Fifty two legal codes are selected on the basis of explicit legal criteria and considered as vertices with their mutual quotations forming the edges in a network which properties are analyzed relying on graph theory. We find that a group of 10 codes are simultaneously the most citing and the most cited by other codes, and are also strongly connected together so forming a "rich club" sub-graph. Three other code communities are also found that somewhat partition the legal field is distinct thematic sub-domains. The legal interpretation of this partition is opening new untraditional lines of research. We also conjecture that many legal systems are forming such new kind of networks that share some properties in common with small worlds but are far denser. We propose to call "concentrated world"

Graphs for Ontology, Law and Policy

Le livre est en accès libre. The book is in open acces

Network Analysis of the French Environmental Code

We perform a detailed analysis of the network constituted by the citations in a legal code, we search for hidden structures and properties. The graph associated to the Environmental code has a small-world structure and it is partitioned in several hidden communities of articles that only partially coincide with the organization of the code as given by its table of content. Several articles are also connected with a low number of articles but are intermediate between large communities. The structure of the Environmental Code is contrasting with the reference network of all the French Legal Codes that presents a rich-club of ten codes very central to the whole French legal system, but no small-world property. This comparison shows that the structural properties of the reference network associated to a legal system strongly depends on the scale and granularity of the analysis, as is the case for many complex systemsComment: AI Approaches to the Complexity of Legal Systems (AICOL 2009), Rotterdam : Netherlands (2009

Água, saúde e territórios : uma breve discussão

A água e o meio ambiente, recursos vitais, interagem de várias maneiras com a saúde humana: vetor de agente microbiano ou tóxicos, ambiente de vida de vetores biológicos ou ainda importante meio de favorecimento de desenvolvimento de epidemias durante e após eventos extremos. Todas essas dimensões de interação entre a água e a saúde humana são tema de políticas públicas diferenciadas, em escalas que variam da supranacional ao local nos territórios que se apresentam hora como locais de apropriação e de vida e hora como lugar de expressão das políticas. Após uma apresentação das principais doenças de maior preocupação para a saúde pública global relacionada à água (amebíase (diarreia), esquistossomose e malária), apresentamos a situação mais específica do território brasileiro, principalmente no que diz respeito à diarreia infantil, a contaminação por cianobactérias e as doenças vetoriais: malária, dengue, esquistossomose e leptospirose, apresentamos algumas medidas recentemente implementadas pelo governo brasileiro para tentar suplantar as questões ligadas à relação entre água e a saúde.Water, at the same time environment and vital resource, interacts in various ways on human health: vector for microbial or toxic agents, living environment for biological vectors, or natural power fostering the development of epidemics during extreme events or disasters. All these dimensions of interaction with human health are the subject of differentiated public policies, at the supranational, national and local scales, in territories that play both as places of ownership and life but also as places for the expression of measures of policies and survey, prevention and health. After a presentation of some water-related diseases among those of greatest concern for global public health (amebiasis, schistosomiasis / bilharziosis and malaria), we present the more specific situation of the Brazilian territory, particularly with regard to infant diarrhea, malaria and dengue, the schistosomiasis and leptospirosis, and some of the measures recently implemented by the Brazilian overnment to try to stop it

Mining CBD

The Convention on Biological Diversity (CBD) has a central position in the system of international environmental law regimes: indeed, it addresses a variety of issues such as climate change (in relation with biodiversity), agricultural biodiversity, marine and coastal biodiversity, and is based on integrative approaches such as the ecosystem approach, promoting the interconnection of knowledge as well as the link between legal instruments, norms and international organizations involved. Through the mining of a textual corpus composed of the CBD (1992) and 364 decisions issued from the Conferences of the Parties (COPs, 1994 to 2014) we show that these themes are addressed continuously throughout the holding of COPs and that the terminology enriched progressively with new notions and concepts sought by each theme. If climate change and the promotion of an integrative ecosystem approach are always taken into account since 1992, agricultural diversity, and quite recently the marine and coastal biodiversity are the most highlighted themes in the work of the COPs. This dynamic is mainly explained by the expert work of the CBD scientific groups or bodies. This eclecticism seems to favour the defragmentation of the various regimes of international environmental law and strengthening their inter-connectivity established notably -but not exclusively- on the basis of a sharing and exploitation of scientific knowledge

Réflexions prospectives sur une protection juridique des réfugiés écologiques

Des migrations majeures issues de catastrophes environnementales sont attendues lors des prochaines décennies. La conception de mesures adaptées de prévention et de réduction des impacts se heurte à l’absence de scenarii migratoires fiables, composant risques environnementaux avec vulnérabilité et résilience sociétale. Ainsi les instruments juridiques de protection des réfugiés écologiques font défaut. Les limites structurelles du droit international des réfugiés, fondé sur le respect de la souveraineté des États et du principe de non-ingérence, ainsi que celles du droit international humanitaire moderne et du droit international de l’environnement ne permettent pas d’envisager une protection à la hauteur des enjeux. La protection juridique des réfugiés écologiques doit adapter ou inventer de nouveaux concepts et mécanismes juridiques tels que la création d’une protection internationale et le recours aux notions d’ingérence écologique, de droit d’asile environnemental, de force majeure, d’État défaillant.Prospective thoughts on a legal protection for ecological refugees. Major migrations induced by environmental disasters are expected for the next decades. The design of adequate prevention and mitigation tools comes up against the low reliability of migration scenarii accounting for environmental risks and societal vulnerability and resilience. Thus legal instruments to protect ecological refugees are lacking. The structural limits of the international law based on the respect of State sovereignty and of the principle of non-interference, as well as those limits of the modern humanitarian international law and international environmental law do not allow to construct a protection tied to the real issue. The legal protection of ecological refugees must adapt and invent new legal concepts and mechanisms like the creation of an international protection and the use of notions like the ones of ecological interference, environmental asylum rights, fortuitous event, failed State.Reflexiones prospectivas sobre una protección jurídica de los refugiados ecológicos. En las próximas décadas se prevén migraciones importantes debidas a catástrofes medioambientales. La concepción de medidas adaptadas de prevención y reducción de sus impactos se choca con la falta de escenarios fiables de migración, que tomen a cuenta tanto a los riesgos medioambientales como a la vulnerabilidad y a la resiliencia de la sociedad. Tampoco existen instrumentos jurídicos de protección de los refugiados ecológicos. Además los límites estructurales del derecho internacional de los refugiados basado en el respeto de la soberanía de los Estados y en el principio de no ingerencia, así como los limites del derecho internacional humanitario moderno y del derecho internacional del medio ambiente no permiten prever una protección a la altura de lo que está en juego. La protección jurídica de los refugiados ecológicos pues, deberá inventar nuevos instrumentos jurídicos y recorrer a nuevos conceptos como ingerencia ecológica, derecho de asilo medioambiental, fuerza mayor, o Estado deficiente

Mining the Web of Science for African cities and climate change (1991–2021)

This study provides a synthetic overview of thirty years of research devoted to urban climate change in Africa. Which cities in Africa are being researched on the impacts of climate change affecting them? What are the main social and urban issues and how are they linked? Is the development of climate services envisaged for these cities? Related to which local issues? Some answers are drawn by text mining the metadata of more than a thousand articles published in the 1991–2021 period and recorded in the Web of Science. The evidences produced are based on the design and exploitation of a taxonomy of keywords forming a set of issues and on their articulation in a network based on their co-occurrences in the articles' metadata. Forty-eight African countries and 134 cities are cited, Cairo, Dar es Salaam, Cape Town, Accra, Lagos, Durban, Nairobi, Addis Ababa, Kampala and Johannesburg being the cities deferring the largest number of studies. The salient urban climate change issues-health, water, energy, social issues and governance, followed by agriculture and food, mitigation, heat, urban territories, risks and hazards-are generally addressed in their interdependences. Urbanization and the implementation of associated policies, as well as the management of water resources, floods health and energy, and land use and land cover changes to a less extent, are proving to be the most pressing challenges. In view of the intricacy of these issues, climate services appear underdeveloped in African cities and barely confined to the acquisition and modeling of environmental data for decision-making in adaptation planning

Analyse saisonniers de la vegetation de cerrado par données du capteur MODIS dans le District Fédéral (Brésil)

O presente estudo visa caracterizar o comportamento sazonal da vegetação do Cerrado por meio de índices de vegetação (NDVI e EVI) do sensor MODIS. A caracterização da sazonalidade foi realizada em áreas com e sem registro de queimadas. Para construção das séries temporais foi utilizado o produto MOD13Q1. As imagens datam do período de 2000 a 2015, com um período de amostragem a cada 16 dias. As transformações de Fourier de séries temporais mostram que os índices de vegetação do Cerrado são amplamente dominados pelo ciclo anual. O comportamento dos índices de vegetação estabelecida para o período 2000-2015 é fortemente controlado pela precipitação estabelecida em relação ao mesmo período. Em alguns anos, os índices de vegetação mostram uma dinâmica mais propagada durante a estação chuvosa (aumento prematuro e amplitude menor do que a amplitude média de climatologia), ou ao contrário, uma atividade mais tardia e mais ampla. Os diagramas de dispersões entre os índices de vegetação obtidos para os locais sem fogo contra os locais queimados, mostram uma separação de dados em três grupos distintos: os índices de vegetação da estação das chuvas, os da estação seca, e, finalmente, os índices que comportam uma assinatura relacionada com o fogo.This study aims to characterize the seasonal behavior of Cerrado vegetation through vegetation indexes (NDVI and EVI) of the MODIS sensor. The characterization of seasonality was carried out in areas with and without recorded fires. NDVI and EVI vegetation indexes from the MOD13Q1 product were used to build time series. The images date from 2000 to 2015, with a 16-day sampling period. Fourier transformations of time series show that the Cerrado vegetation indexes are largely dominated by the annual cycle. The monthly climatology of vegetation indexes established for the period 2000-2015 is strongly controlled by the rainfall monthly climatology established over the same period. In some years the vegetation indexes show a more dynamic spread during the rainy season (a premature increase and lower amplitude than the average amplitude of climatology), or on the contrary a later and more extensive activity. Dispersion diagrams between vegetation indexes obtained for sites without fire versus the burned sites show a separation of data into three distinct groups: the vegetation indexes of the rainy season, those in the dry season, and finally the indexes with a fire-related signature.Cette étude vise à caractériser le comportement saisonnier de la végétation du Cerrado par indice de végétation (NDVI et EVI) du capteur MODIS. La caractérisation de la saisonnalité a été réalisée dans les zones avec et sans registre de brûlées. Pour la construction de la série de temporelle, nous avons utilisé le MOD13Q1. Les images datent de 2000 à 2015, avec une période d’échantillonnage tous les 16 jours. La série chronologique des transformations de Fourier montrent que les indices de végétation du Cerrado sont largement dominés par le cycle annuel. Le comportement des indices de végétations établies pour la période 2000-2015 est fortement contrôlé par la précipitation sur la même période. En quelques années, les indices de végétation montrent une propagation plus dynamique pendant la saison des pluies (début prématuré et une amplitude inférieure à l’amplitude moyenne de la climatologie), ou plutôt une activité plus en retard et plus large. Les diagrammes de dispersion entre les indices de végétation obtenus pour les sites sans feu contre les sites brûlés, montrent une séparation des données en trois groupes distincts : les indices de végétation de la saison des pluies, saison sèche, et enfin les indices qui contiennent une signature liée à l’incendie

Multi-agent modeling for water policy impact assessment : a road map

Politicas públicas de água têm grande influência sobre diferentes tipos de recursos (recursos hídricos, da terra e do solo; infraestrutura e instalações prediais; recursos financeiros; informação e conhecimento ambiental; etc.). Elas atuam sobre agentes individuais ou coletivos (usuários, gestores, empresas públicas ou privadas, associações, etc.), assim como como regras e normas de comportamento que estes atores são os destinatários ou agentes. Sistemas complexos, se for o caso, essas políticas têm vários tipos de efeitos, esperados e inesperados, os efeitos diretos e indiretos, sociais, econômicos, ambientais e ecosistêmica. O atual desenvolvimento de plataformas multi-agente abre uma nova área para a definição, concepção, implementação e monitoramento da gestão da água, produzindo simulações ex ante do impacto das medidas que promovem políticas públicas de água e da evolução provável da situação sócio--HYDROSYSTEM em causa. Aqui vamos dar uma visão geral das novas oportunidades de modelagem de política da água e avaliação de impacto, que resumem as etapas do processo de modelagem e apresentar os principais ingredientes que entram na composição de uma plataforma dedicada a simulações de impacto. Também argumentam que o interesse de construir cenários de água e produção de indicadores úteis para a tomada de decisão sobre o uso, distribuição e gestão dos recursos hídricos à escala da bacia.Water policies have a great impact upon different types of resources (water, land and soil resour-ces; infrastructure and facilities; financial resour-ces; environmental knowledge and information; etc.). They involve many individual or collective actors (users, managers, public or private companies, associations, etc.) as well as rules and norms of behavior that these actors are the reci-pients or agents. Complex systems, if any, these policies have several kinds of effects, expected and unexpected, direct and indirect effects, societal, economic, environmental and eco-systemic. The current development of multi-agent platforms opens up a new area for the definition, design, implementation and monitoring of water management by producing ex ante simulations of the impact of measures that promote water public policies and of the likely evolution of the socio-hydrosystem concerned. Here we give a quick overview of these new opportunities of water policy modeling and impact assessment. We summarize the steps of the modeling process and present the main ingredients entering in the composition of a platform dedicated to impact simulations. We also argue the interest of building water scenarios and producing useful indicators for decision-making regarding the use, distribu-tion and management of water resources at the basin-scale