6,819 research outputs found
Efficient computational strategies for doubly intractable problems with appli- cations to Bayesian social networks
No full textPowerful ideas recently appeared in the literature are adjusted and combined to design improved samplers for doubly intractable target distributions with a focus on Bayesian exponential random graph models. Different forms of adaptive Metropolis–Hastings proposals (vertical, horizontal and rectangular) are tested and merged with the delayed rejection (DR) strategy with the aim of reducing the variance of the resulting Markov chain Monte Carlo estimators for a given computational time. The DR is modified in order to integrate it within the approximate exchange algorithm (AEA) to avoid the computation of intractable normalising constant that appears in exponential random graph models. This gives rise to the AEA + DR: a new methodology to sample doubly intractable distributions that dominates the AEA in the Peskun ordering (Peskun Biometrika 60:607– 612, 1973) leading to MCMC estimators with a smaller asymptotic variance. The Bergm package for R (Caimo and Friel J. Stat. Softw. 22:518–532, 2014) has been updated to incorporate the AEA + DR thus including the possibility of adding a higher stage proposals and different forms of adaptation
Delayed rejection algorithm to estimate Bayesian social networks
No full textStatistical social network analysis has become a very active and fertile area of research in the recent past. Recent developments in Bayesian computational methods have been successfully applied to estimate social network models. The Delayed rejection (DR) strategy is a modification of the Metropolis-Hastings (MH) algorithms that reduces the variance of the resulting Markov chain Monte Carlo estimators and allows partial adaptation of the proposal distribution. In this paper we show how the DR strategy can be exploited to estimate dyadic independence social network models leading to an average 40% variance reduction relative to the competing MH algorithm, confirming that DR dominates, in terms of Peskun ordering, the MH algorithm
Sustainable energy governance practice in South Tyrol (Italy): A probabilistic bipartite network model
No full textAt the national scale, almost all of the European countries have already achieved energy transition targets, while at the regional and local scales, there is still some potential to further push sustainable energy transitions. Regions and localities have the support of political, social, and economic actors who make decisions for meeting existing social, environmental and economic needs recognizing local specificities. These actors compose the sustainable energy governance that is fundamental to effectively plan and manage energy resources. In collaborative relationships, these actors share, save, and protect several kinds of resources, thereby making energy transitions deeper and more effective. This research aimed to analyse a part of the sustainable energy governance composed of formal relationships between municipalities and public utilities and to investigate the opportunities to further spread sustainable energy development within a region. In the case study from South Tyrol, Italy, the network structures and dynamics of this part of the actual energy governance were investigated through a social network analysis and Bayesian exponential random graph models. The findings confirmed that almost all of the collaborations are based on spatial closeness relations and that the current network structures do not permit a further spread of the sustainable energy governance. The methodological approach can be replicated in other case studies and the findings are relevant to support energy planning choices at regional and local scales
Collaborations in Environmental Initiatives for an Effective “Adaptive Governance” of Social–Ecological Systems: What Existing Literature Suggests
No full textMoving from the scientific literature on the evaluation of environmental projects and programs,
this study identifies how and under which conditions collaborations in environmentally sustainable
projects are considered effective for the adaptive governance of SES. The method adopted
is a systematic literature review based on the quantitative and qualitative analysis of 56 articles selected
through specific queries on the SCOPUS database and published from 2004 to 2020. Results
of the quantitative analysis identify conditions able to evaluate collaborations, highlighting the need
to adopt a transdisciplinary approach analysing both social and ecological challenges and assessing
both social and ecological results. Moreover, they suggest preferring using primary data involving
multi-sector and multi-scale actors and enlarging the geographical context to the most vulnerable
countries. The results of the qualitative analysis provide specific recommendations for collaborations
being effective when related to communication, equity, foresight, and respect, which need to
be further strengthened by all actors. Multiplicity in visions and approaches should be seen as a
resource able to stimulate creativity in social arrangements and environmental practices, making
collaborations in environmental projects instrumental for the effectiveness of adaptive governance
of SES
Exploring synergies in the collaborative governance of European forests supported by the EU-funded LIFE Programme
No full textWith the EU Green Deal strategy in the background, the European
Union (EU) is developing a new policy framework related to forest
ecosystems and forestry aiming to address global environmental
challenges, especially through the new EU Forest Strategy for 2030,
the EU Biodiversity Strategy for 2030, the “Fit for 55” package for
climate neutrality, and the new Common Agricultural Policy 2023-
2027. All the policies mentioned above recognize networking and
collaboration fundamental to achieve effectiveness of activities.
Integrating multiple actions implemented in European forests in a
sharing effort perspective and diffuse them through the replication of
good practices, potentially could contribute to a wider societal
transition able to address global environmental challenges affecting
not only forests but, more generally, all ecosystems.
The LIFE Programme could represent one example of an EU program
devoted to concretizing the collaborative governance in forest
ecosystems through the proposition and implementation of LIFE
projects by partnerships of multiple actors. In effect, the LIFE
Programme in the last programming period (2014-2020) promotes
multiple projects dealing with environmental challenges related to
forests, e.g., due to climate change.
Exploring concrete examples of collaborative governance
implemented in forests through LIFE projects, could be helpful to get
insights valuable to enhance the governance of forests and, more
generally, the collaborative environmental governance. In particular,
enhancing knowledge of connections and synergies is strategic for
promoting coherence between multiple actions, which need to
integrate different and specific social needs and policy objectives with
global environmental challenges. Thus, this study focuses on the
identification of synergies between (i) projects key elements, (ii)
projects beneficiaries, (iii) policies fostering LIFE projects, performing
the Social Network Analysis.
From selecting projects in the LIFE Programme database, we get 61
LIFE projects co-funded from 2014 to 2020. They are implemented in
the whole European territory. Additionally, we identify 113 keywords,
282 beneficiaries and 28 EU policies.
Results evidence the high value of forests for nature and biodiversity
as the main source of synergies between multiple activities. This is
confirmed also by the analysis of policies. Conversely, central issues
like bioeconomy and soil protection are not equally shared by projects.
Additionally, forests emerge as tools to create synergies for adaptation
to climate change in rural and urban areas. Actors creating networks of
collaborations are especially public bodies or NGOs placed in south
Europe
Il ruolo degli enti di gestione delle aree protette nella governance ambientale collaborativa per la biodiversità in Italia supportata dal Programma europeo LIFE 2014-2020.
No full textOggi più che mai l’intera società ha preso consapevolezza di come il proprio benessere sia strettamente connesso alla qualità degli ambienti naturali e della biodiversità. Tale cognizione è sottolineata in numerosi e recenti programmi politici sia livello nazionale che internazionale (es. Agenda 2030 per lo Sviluppo Sostenibile, Strategia Europea per la Biodiversità 2030). In questo contesto, la corretta gestione delle aree protette risulta essere di fondamentale importanza. Riferendosi al territorio italiano, è doveroso tenere in considerazione che la maggior parte delle aree naturali protette è ubicata nelle cosiddette “Aree Interne”, marginali per quanto riguarda la fornitura di servizi alla persona, ma ricche di risorse ambientali e culturali che necessitano di interventi specifici volti a migliorare la qualità della vita
dei residenti valorizzando le caratteristiche intrinseche dei territori. Conseguentemente, gli enti di gestione delle aree protette rivestono un ruolo strategico nella definizione e nell’implementazione di azioni concrete volte a contribuire al raggiungimento di uno sviluppo sostenibile che tenga conto sia dei bisogni sociali che ecologici specifici al contesto, in quanto figure terze tra autorità nazionali e realtà locali. Nonostante sia chiaro il ruolo chiave di tali enti, la letteratura presenta criticità rispetto al loro operato, soprattutto per quanto riguarda la mancanza di un atteggiamento proattivo di tali istituzioni, dovuta a un atteggiamento sovente di mera sorveglianza, associabile a una visione di comando-controllo della governance territoriale. Al contrario, è universalmente condivisa la necessità di partecipazione e coinvolgimento attivo da parte di tutte le tipologie di attori – politiche, economiche e civili – per garantire un’efficace gestione territoriale, in accordo alla tendenza di associare al concetto di governance ambientale quello di governance collaborativa. Questa prospettiva rafforza il ruolo del Programma europeo LIFE, uno dei maggiori strumenti per il cofinanziamento di progetti ambientali proposti generalmente da partenariati di attori. Esso, infatti, si presenta come uno degli strumenti chiave per migliorare la gestione delle aree naturali protette e per promuovere la conservazione e il recupero di habitat e specie protette nel territorio europeo, soprattutto attraverso i progetti LIFE Natura (LIFE-NAT). Riferendosi all’ultima programmazione LIFE, e in particolare ai 45 progetti LIFE-NAT implementati in Italia tra il 2014 e il 2019, questo studio vuole analizzare il ruolo degli enti di gestione delle aree protette rivestito nei partenariati supportati da LIFE attraverso uno studio della connettività tra i 283 beneficiari cofinanziati dal programma e la localizzazione degli stessi nel territorio italiano. L’obiettivo è testare l’ipotesi secondo cui tali enti possano definirsi catalizzatori di innovazione e mediatori tra le diverse parti coinvolte all’interno della programmazione LIFE-NAT. L’elevato ammontare di progetti coordinati dagli enti di gestione delle aree protette (28,8%), e dagli stessi come beneficiari di progetto (21,7%), soprattutto nelle Aree Interne italiane (70,96%), dimostra come questa categoria rivesta un ruolo strategico da prendere in considerazione rispetto all’implementazione di azioni legate alla natura e alla biodiversità supportate da LIFE, soprattutto nelle aree svantaggiate del centro-sud Italia nel quale ricoprono ruoli di maggiore centralità nella rete di relazioni tra beneficiari dei diversi partenariati dei progetti LIFE analizzati
Application of the DPSIR and Social-Ecological Network Frameworks to analyse social-ecological relationships in AFOLU activities addressed by the LIFE Programme.
No full textRelational attributes in social ecological systems fostering the transition towards a bio‐based economy: insights and operative indications
No full textThe bioeconomy concept makes explicit the close connection between humanity and nature. The notion
refers to the multiple ways of environmental‐friendly production based on biological processes, which
realisation requires cross‐sectoral and interdisciplinary research and the involvement of different types
of actors interacting with the ecological systems across scales and societal domains. The interplay among
society and nature is theorized in the Social‐Ecological Systems (SES) approach which underlines that
every social process is an embedded part of nature. In this framework, collaboration, conceptualize as a
participative approach aimed to involve stakeholders to identify priorities in management actions,
constitutes an essential tool to empower communities by identifying novel solutions and strategies to
solve environmental issues through collective learning. Powered by external and self‐evaluation
processes, collaboration allows people to increase the effectiveness of their actions and to adjust them
to emerging needs, by learning from previous successes and failures. Nevertheless, at present knowledge
on how collaboration can enhance the good governance of SES and the transition towards a bioeconomy
is still limited, with the risk that it could be conceptualized as a panacea solution. Furthermore, the close
connection among humanity and environment requires a greater awareness on relations arising among
actors (i.e. State, market, community, and research organizations) involved in environmental governance.
Moving from scientific literature on projects and programs evaluation, this study aims to analyse how
relations and interactions among actors involved in SES management have been conceptualized and
evaluated. The final aim is to identify different typologies of relational attributes among them by
providing policy indications for the environmental governance. The literature review, based on the
analysis of 68 articles selected through queries on SCOPUS database, shows that the effective
management of SES requires the involvement of all types of actors having different responsibilities and
duties associated to their stakeholder group. At present evaluations reported in scientific articles mostly
focus on public authorities’ role, with a minor attention on other actors’ contribution. A relation is made
at least by two different entities, this requires not to focalize only to one side, but also to the others, in
this case, community, market actors and research organizations. In particular there is the need to clarify
direct relationships between research organizations and community, which are analysed by very few
papers. In addition, there is the need to measure quantitatively stakeholders involvement on
environmental collective actions through a network approach in order to identify who has a central role
on sustainability transition and to what extent actors belonging to the four categories play a relevant role
on it
Bayesian model selection for exponential random graph models.” Social Networks
No full textExponential random graph models are a class of widely used exponential fam-ily models for social networks. The topological structure of an observed network is modelled by the relative prevalence of a set of local sub-graph configurations termed network statistics. One of the key tasks in the application of these mod-els is which network statistics to include in the model. This can be thought of as statistical model selection problem. This is a very challenging problem—the posterior distribution for each model is often termed “doubly intractable ” since computation of the likelihood is rarely available, but also, the evidence of the posterior is, as usual, intractable. The contribution of this paper is the devel-opment of a fully Bayesian model selection method based on a reversible jump Markov chain Monte Carlo algorithm extension of Caimo and Friel (2011) which estimates the posterior probability for each competing model.
[Poesia] Três poemas de Alberto Secama
No full textThree poems by Alberto Secama. About the author: Alberto Secama is an Angolan poet who has poems published on many websites and on facebook:https://www.facebook.com/Xungurra/abouthttp://www.pordentrodaafrica.com/cultura/africa-em-verso-rio-kwanza-por-alberto-secamahttp://www.pordentrodaafrica.com/cultura/africa-em-verso-zong-por-alberto-secamahttp://www.pordentrodaafrica.com/cultura/coluna-africa-em-verso-o-sol-la-fora-por-alberto-secamaTres poemas de Alberto Secama. Sobre el autor: Alberto Secama es un poeta angoleño que tiene poemas publicados en varios sitios y en el facebook:https://www.facebook.com/Xungurra/abouthttp://www.pordentrodaafrica.com/cultura/africa-em-verso-rio-kwanza-por-alberto-secamahttp://www.pordentrodaafrica.com/cultura/africa-em-verso-zong-por-alberto-secamahttp://www.pordentrodaafrica.com/cultura/coluna-africa-em-verso-o-sol-la-fora-por-alberto-secamaTrês poemas de Alberto Secama. Sobre o autor: Alberto Secama é um poeta angolano que possui poemas publicados em vários sites e no facebook:https://www.facebook.com/Xungurra/abouthttp://www.pordentrodaafrica.com/cultura/africa-em-verso-rio-kwanza-por-alberto-secamahttp://www.pordentrodaafrica.com/cultura/africa-em-verso-zong-por-alberto-secamahttp://www.pordentrodaafrica.com/cultura/coluna-africa-em-verso-o-sol-la-fora-por-alberto-secam
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