1,738 research outputs found
Methodological Guide to Co-design Climate-smart Options with Family Farmers
Climate-smart agriculture (CSA) seeks to improve productivity for the achievement of food
security (pillar 1: Productivity), to develop a better ability to adapt (pillar 2: Adaptation), and
to limit greenhouse gas emissions (pillar 3: Mitigation). Technical and organizational
innovations are needed to find synergies among those three pillars.
Innovation (its creation and its operation) is a social phenomenon. Many studies worldwide
have shown that promoting a sustainable change and innovation within organizations has to
be analyzed and implemented with stakeholders. Thus, the ability of local actors to tackle
climate change and mitigate its effects will depend on their ability to innovate and mobilize
material and non-material resources, to articulate links among national policies, not only
between themselves, but also undertaking actions at the local level. To support stakeholders
in the development of responses to this challenge, we propose the development of open
innovation platforms, in which all local actors may participate. These platforms are virtual,
physical, or physico-virtual spaces to learn, jointly conceive, and transform different
situations; they are generated by individuals with different origins, different backgrounds and
interests (Pali and Swaans, 2013).The purpose of this manual is to provide a seven-step methodology to allow family farmers to co-build and adopt CSA options to tackle climate change in an open innovation platfor
The influence of electron collisions on non-LTE Li line formation in stellar atmospheres
The influence of the uncertainties in the rate coefficient data for
electron-impact excitation and ionization on non-LTE Li line formation in cool
stellar atmospheres is investigated. We examine the electron collision data
used in previous non-LTE calculations and compare them to recent calculations
that use convergent close-coupling (CCC) techniques and to our own calculations
using the R-matrix with pseudostates (RMPS) method. We find excellent agreement
between rate coefficients from the CCC and RMPS calculations, and reasonable
agreement between these data and the semi-empirical data used in non-LTE
calculations up to now. The results of non-LTE calculations using the old and
new data sets are compared and only small differences found: about 0.01 dex (~
2%) or less in the abundance corrections. We therefore conclude that the
influence on non-LTE calculations of uncertainties in the electron collision
data is negligible. Indeed, together with the collision data for the charge
exchange process Li(3s) + H Li^+ + H^- now available, and barring the
existence of an unknown important collisional process, the collisional data in
general is not a source of significant uncertainty in non-LTE Li line formation
calculations.Comment: 8 pages, accepted by Astronomy and Astrophysics; Replaced with minor
corrections following proof
Mercury removal in wastewater by iron oxide nanoparticles
Mercury is one of the persistent pollutants in wastewater; it is becoming a severe environmental and public health problem, this is why nowadays its removal is an obligation. Iron oxide nanoparticles are receiving much attention due to their properties, such as: great biocompatibility, ease of separation, high relation of surface-area to volume, surface modifiability, reusability, excellent magnetic properties and relative low cost. In this experiment, Fe3O4 and Îł-Fe2O3 nanoparticles were synthesized using iron salts and NaOH as precipitation agents, and Aloe Vera as stabilizing agent; then these nanoparticles were characterized by three different measurements: first, using a Zetasizer Nano ZS for their size estimation, secondly UV-visible spectroscopy which showed the existence of resonance of plasmon at λmaxâŒ360 nm, and lastly by Scanning Electron Microscopy (SEM) to determine nanoparticles form. The results of this characterization showed that the obtained Iron oxides nanoparticles have a narrow size distribution (âŒ100nm). Mercury removal of 70% approximately was confirmed by atomic absorption spectroscopy measurements
Co-designing climate-smart farming systems with local stakeholders: A methodological framework for achieving large-scale change
The literature is increasing on how to prioritize climate-smart options with stakeholders but relatively few examples exist on how to co-design climate-smart farming systems with them, in particular with smallholder farmers. This article presents a methodological framework to co-design climate-smart farming systems with local stakeholders (farmers, scientists, NGOs) so that large-scale change can be achieved. This framework is based on the lessons learned during a research project conducted in Honduras and Colombia from 2015 to 2017. Seven phases are suggested to engage a process of co-conception of climate-smart farming systems that might enable implementation at scale: (1) âexploration of the initial situation,â which identifies local stakeholders potentially interested in being involved in the process, existing farming systems, and specific constraints to the implementation of climate-smart agriculture (CSA); (2) âco-definition of an innovation platform,â which defines the structure and the rules of functioning for a platform favoring the involvement of local stakeholders in the process; (3) âshared diagnosis,â which defines the main challenges to be solved by the innovation platform; (4) âidentification and ex ante assessment of new farming systems,â which assess the potential performances of solutions prioritized by the members of the innovation platform under CSA pillars; (5) âexperimentation,â which tests the prioritized solutions on-farm; (6) âassessment of the co-design process of climate-smart farming systems,â which validates the ability of the process to reach its initial objectives, particularly in terms of new farming systems but also in terms of capacity building; and (7) âdefinition of strategies for scaling up/out,â which addresses the scaling of the co-design process. For each phase, specific tools or methodologies are used: focus groups, social network analysis, theory of change, life-cycle assessment, and on-farm experiments. Each phase is illustrated with results obtained in Colombia or Honduras
Recombination in passivating contacts: investigation into the impact of the contact work function on the obtained passivation
Improving the passivation of contacts in silicon solar cells is crucial for reaching high-efficiency devices. Herein, the impact of the contact work function on the obtained passivation is examined and quantified using a novel methodâquasi-steady-state photoluminescenceâwhich provides access to the surface saturation current density after metallization (J 0s,m). The obtained J 0s,m indicates an improvement of the surface passivation when contacts with high work function are applied onto Si wafers passivated with aluminum oxide, regardless of the wafer doping type. This improvement is mainly due to the amplification of the imbalance between the electron and hole concentrations near the Si interface. The passivation quality is reduced when using contacts with low work function in which the recombination rate increases via the charge-assisted carrier population control. Herein, the vital importance of selecting suitable metals to minimize contact recombination in high-efficiency solar cells is pointed
Synthesis of Silver nanoparticles (AgNPs) with Antibacterial Activity
The synthesis of nanomaterials is currently one of the most active in nanoscience branches; especially those help improve the human quality life. Silver nanoparticles (AgNPs) are an example of this as it is known to have inhibitory and bactericidal effects. In this work, we report the synthesis of silver nanoparticles by chemical reduction method of silver nitrate (AgNO3) from aqueous solution, using a mix of polivinyl pyrrolidone (PVP) - Aloe Vera as reducing agent and for stabilization and control of particle size. Silver nanoparticles obtained were characterized by Scanning Electron Microscopy (SEM), UV-visible spectroscopy and measurements using Zetasizer Nano ZS were applied to size estimation. The existence of surface plasmon resonance peak at λmax ⌠420 nm is evidence of silver nanoparticles formation. It was possible to standardize an appropriate protocol for the evaluation of bactericidal activity of the nanoparticles, for mesophilic microorganisms. Bactericidal activity above 90% against these kinds of bacteria was demonstrated. © Published under licence by IOP Publishing Ltd
Zinc-modified nanopolymers improve the quality of resin-dentin bonded interfaces
Introduction: Demineralized collagen fibers at the hybrid layer are susceptible to degradation. Remineralization may aid to
improve bond longevity.
Objectives: The aim of the present study was to infiltrate zinc and calcium-loaded polymeric nanoparticles into demineralized
dentin to facilitate hybrid layer remineralization.
Materials and methods: Zinc or calcium-loaded polymeric nanoparticles were infiltrated into etched dentin, and Single Bond Adhesive was applied. Bond strength was tested after
24 h and 6 months storage. Nanomechanical properties, dyeassisted confocal laser microscopy, and Massonâs trichrome
staining evaluation were performed to assess for the hybrid layer morphology, permeability, and remineralization ability
after 24 h and 3 months. Data were analyzed by ANOVA and StudentâNewmanâKeuls multiple comparisons tests (p < 0.05).
Results: Immediate bond strength was not affected by nanoparticles infiltration (25 to 30 MPa), while after 6 months, bond strengths were maintained (22 to 24 MPa). After
3 months, permeability occurred only in specimens in which nanoparticles were not infiltrated. Dentin remineralization, at
the bottom of the hybrid layer, was observed in all groups.
After microscopy analysis, zinc-loaded nanoparticles were shown to facilitate calcium deposition throughout the entire
hybrid layer. Youngâs modulus at the hybrid layer increased from 2.09 to 3.25 GPa after 3 months, in specimens with zinc nanoparticles; meanwhile, these values were reduced from
1.66 to 0.49 GPa, in the control group.
Conclusion: Infiltration of polymeric nanoparticles into demineralized dentin increased long-term bond strengths.
Zinc-loaded nanoparticles facilitate dentin remineralization within the complete resinâdentin interface.
Clinical relevance: Resinâdentin bond longevity and dentin remineralization at the hybrid layer were facilitated by zincloaded
nanoparticles.This work was supported by a grant, MINECO/FEDER MAT2014-52036-P
Hydroacoustics as a tool to examine the effects of Marine Protected Areas and habitat type on marine fish communities
Abstract Hydroacoustic technologies are widely used in fisheries research but few studies have used them to examine the effects of Marine Protected Areas (MPAs). We evaluate the efficacy of hydroacoustics to examine the effects of closure to fishing and habitat type on fish populations in the Cabo Pulmo National Park (CPNP), Mexico, and compare these methods to Underwater Visual Censuses (UVC). Fish density, biomass and size were all significantly higher inside the CPNP (299%, 144% and 52% respectively) than outside in non-MPA control areas. These values were much higher when only accounting for the reefs within the CPNP (4715%, 6970% and 97% respectively) highlighting the importance of both habitat complexity and protection from fishing for fish populations. Acoustic estimates of fish biomass over reef-specific sites did not differ significantly from those estimated using UVC data, although acoustic densities were less due to higher numbers of small fish recorded by UVC. There is thus considerable merit in nesting UVC surveys, also providing species information, within hydroacoustic surveys. This study is a valuable starting point in demonstrating the utility of hydroacoustics to assess the effects of coastal MPAs on fish populations, something that has been underutilised in MPA design, formation and management
Sentinel network for monitoring in vitro susceptibility of Plasmodium falciparum to antimalarial drugs in Colombia: a proof of concept
Drug resistance is one of the principal obstacles blocking worldwide malaria control. In Colombia, malaria remains a major public health concern and drug-resistant parasites have been reported. In vitro drug susceptibility assays are a useful tool for monitoring the emergence and spread of drug-resistant Plasmodium falciparum. The present study was conducted as a proof of concept for an antimalarial drug resistance surveillance network based on in vitro susceptibility testing in Colombia. Sentinel laboratories were set up in three malaria endemic areas. The enzyme linked immunosorbent assay-histidine rich protein 2 and schizont maturation methods were used to assess the susceptibility of fresh P. falciparum isolates to six antimalarial drugs. This study demonstrates that an antimalarial drug resistance surveillance network based on in vitro methods is feasible in the field with the participation of a research institute, local health institutions and universities. It could also serve as a model for a regional surveillance network. Preliminary susceptibility results showed widespread chloroquine resistance, which was consistent with previous reports for the Pacific region. However, high susceptibility to dihydroartemisinin and lumefantrine compounds, currently used for treatment in the country, was also reported. The implementation process identified critical points and opportunities for the improvement of network sustainability strategies.PAHO [057-1-3144141]; COLCIENCIAS [ID 2229-405-20319]info:eu-repo/semantics/publishedVersio
Defining and cataloging exoplanets: The exoplanet.eu database
We describe an online database for extra-solar planetary-mass candidates,
updated regularly as new data are available. We first discuss criteria for the
inclusion of objects in the catalog: "definition" of a planet and several
aspects of the confidence level of planet candidates. {\bf We are led to point
out the conflict between sharpness of belonging or not to a catalogue and
fuzziness of the confidence level.} We then describe the different tables of
extra-solar planetary systems, including unconfirmed candidates (which will
ultimately be confirmed, or not, by direct imaging). It also provides online
tools: histogrammes of planet and host star data, cross-correlations between
these parameters and some VO services. Future evolutions of the database are
presented.Comment: Accepted in Astronomy and Astrophysics (revised version
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