1,840 research outputs found
Supporting Spatial Management of Data-Poor, Small-Scale Fisheries With a Bayesian Approach
Marine conservation areas are an important tool for the sustainable management of
multispecies, small-scale fisheries. Effective spatial management requires a proper
understanding of the spatial distribution of target species and the identification of its
environmental drivers. Small-scale fisheries, however, often face scarcity and low-quality
of data. In these situations, approaches for the prioritization of conservation areas need
to deal with scattered, biased, and short-term information and ideally should quantify
data- and model-specific uncertainties for a better understanding of the risks related
to management interventions. We used a Bayesian hierarchical species distribution
modeling approach on annual landing data of the heavily exploited, small-scale, and
data-poor fishery of Chwaka Bay (Zanzibar) in the Western Indian Ocean to understand
the distribution of the key target species and identify potential areas for conservation.
Few commonalities were found in the set of important habitat and environmental
drivers among species, but temperature, depth, and seagrass cover affected the spatial
distribution of three of the six analyzed species. A comparison of our results with
information from ecological studies suggests that our approach predicts the distribution
of the analyzed species reasonably well. Furthermore, the two main common areas
of high relative abundance identified in our study have been previously suggested by
the local fisher as important areas for spatial conservation. By using short-term, catch
per unit of effort data in a Bayesian hierarchical framework, we quantify the associated
uncertainties while accounting for spatial dependencies. More importantly, the use of
accessible and interpretable tools, such as the here created spatial maps, can frame a
better understanding of spatio-temporal management for local fishers. Our approach,
thus, supports the operability of spatial management in small-scale fisheries suffering
from a general lack of long-term fisheries information and fisheries independent data.En prens
Synthesis and antibacterial effects of cobaltâcellulose magnetic nanocomposites
© The Royal Society of Chemistry. Green synthesis is employed to prepare cobalt/cellulose nanocomposites with cubic (α-cobalt) cobalt as a main component with antibacterial and magnetic properties. An in situ reduction of aqueous solutions of cobalt ions on a model cellulose substrate surface using hydrogen gas affords spherical, cellulose-stabilised cobalt nanoclusters with magnetic properties and an average diameter of 7 nm that are distributed evenly over the surface of the cellulose fibres. These cobalt/cellulose nanocomposites exhibit good antibacterial action against opportunistic pathogens both Gram-positive (S. aureus) and Gram-negative (E. coli, A. baumannii and P. aeruginosa), with zones of inhibition up to 15 mm, thereby encouraging the deployment of these advanced materials for the treatment of wastewater or within medical dressings. This method of preparation is compared with the analogous in situ reduction of cobalt ions on a cellulose surface using sodium borohydride as reducing agent
Using a Bayesian modelling approach (INLAâSPDE) to predict the occurrence of the Spinetail Devil Ray (Mobular mobular)
To protect the most vulnerable marine species it is essential to have an understanding of their spatiotemporal distributions. In recent decades, Bayesian statistics have been successfully used to quantify uncertainty surrounding identified areas of interest for bycatch species. However, conventional simulation-based approaches are often computationally intensive. To address this issue, in this study, an alternative Bayesian approach (Integrated Nested Laplace Approximation with Stochastic Partial Differential Equation, INLA-SPDE) is used to predict the occurrence of Mobula mobular species in the eastern Pacific Ocean (EPO). Specifically, a Generalized Additive Model is implemented to analyze data from the Inter-American Tropical Tuna Commissionâs (IATTC) tropical tuna purse-seine fishery observer bycatch database (2005â2015). The INLA-SPDE approach had the potential to predict both the areas of importance in the EPO, that are already known for this species, and the more marginal hotspots, such as the Gulf of California and the Equatorial area which are not identified using other habitat models. Some drawbacks were identified with the INLA-SPDE database, including the difficulties of dealing with categorical variables and triangulating effectively to analyze spatial data. Despite these challenges, we conclude that INLA approach method is an useful complementary and/or alternative approach to traditional ones when modeling bycatch data to inform accurately management decisions.En prensa2,92
A Fully Abstract Symbolic Semantics for Psi-Calculi
We present a symbolic transition system and bisimulation equivalence for
psi-calculi, and show that it is fully abstract with respect to bisimulation
congruence in the non-symbolic semantics.
A psi-calculus is an extension of the pi-calculus with nominal data types for
data structures and for logical assertions representing facts about data. These
can be transmitted between processes and their names can be statically scoped
using the standard pi-calculus mechanism to allow for scope migrations.
Psi-calculi can be more general than other proposed extensions of the
pi-calculus such as the applied pi-calculus, the spi-calculus, the fusion
calculus, or the concurrent constraint pi-calculus.
Symbolic semantics are necessary for an efficient implementation of the
calculus in automated tools exploring state spaces, and the full abstraction
property means the semantics of a process does not change from the original
Doping of inorganic materials in microreactors â preparation of Zn doped FeâOâ nanoparticles
Microreactor systems are now used more and more for the continuous production of metal nanoparticles and metal oxide nanoparticles owing to the controllability of the particle size, an important property in many applications. Here, for the first time, we used microreactors to prepare metal oxide nanoparticles with controlled and varying metal stoichiometry. We prepared and characterised Zn-substituted FeâOâ nanoparticles with linear increase of Zn content (ZnxFeââxOâ with 0 †x †0.48), which causes linear increases in properties such as the saturation magnetization, relative to pure FeâOâ. The methodology is simple and low cost and has great potential to be adapted to the targeted doping of a vast array of other inorganic materials, allowing greater control on the chemical stoichiometry for nanoparticles prepared in microreactors
Tracking the reflexivity of the (dis)engaged citizen: some methodological reflections
The relationship between governments and citizens in many contemporary democracies is haunted by uncertainty and sociologists face the task of listening effectively to citizensâ own reflections on this uncertain relationship. This article reflects on the qualitative methodology of a recently completed UK project which used a combination of diary and multiple interviews/ focus groups to track over a fieldwork period of up to a year citizensâ reflections on their relationship to a public world and the contribution to this of their media consumption. In particular, the article considers how the projectâs multiple methods enabled multiple angles on the inevitable artificiality and performative dimension of the diary process, resulting in rich data on peopleâs complex reflections on the uncertain position of the contemporary citizen
Expression of bovine cytosolic 5â-nucleotidase (cN-II) in yeast: nucleotide pools disturbance and its consequences on growth and homologous recombination
Cytosolic 5âČ-nucleotidase II is a widespread IMP hydrolyzing enzyme, essential for cell vitality, whose role in nucleotide metabolism and cell function is still to be exactly determined. Cytosolic 5âČ-nucleotidase overexpression and silencing have both been demonstrated to be toxic for mammalian cultured cells. In order to ascertain the effect of enzyme expression on a well-known eukaryote simple model, we expressed cytosolic 5âČ-nucleotidase II in Saccharomyces cerevisiae, which normally hydrolyzes IMP through the action of a nucleotidase with distinct functional and structural features. Heterologous expression was successful. The yeast cells harbouring cytosolic 5âČ-nucleotidase II displayed a shorter duplication time and a significant modification of purine and pyrimidine derivatives concentration as compared with the control strain. Furthermore the capacity of homologous recombination in the presence of mutagenic compounds of yeast expressing cytosolic 5âČ-nucleotidase II was markedly impaired
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