Access to genes: linkages between genebanks and farmers’ seed systems

Genebanks conserve key resources for handling current and future challenges to food production and security. The role of genebanks has evolved from primarily serving plant breeders to include long-term biodiversity conservation and distribution to a wider user community. International policy frameworks stress the complementarity of ex situ and in situ conservation and management, but a dichotomy prevails in the public and scholarly agricultural development discourse. Here, we present a study of existing linkages between the two conservation and management approaches, their challenges and future options. First, we show that farmers, farmer organizations, and NGOs now comprise a considerable user group of genebank material, receiving at least 8% of the seed samples distributed from international genebanks in 2015, on par with the proportion distributed to the commercial seed sector. Second, we map and categorize approaches to introduce genebank material into farmers’ seed systems. Based on a survey, interviews and a literature review we categorize direct genebank-farmer linkages into six categories: (1) Reintroduction, (2) Emergency Seed Interventions, (3) Community Seed Banks, (4) Participatory Plant Breeding, (5) Variety Introduction, and (6) Integrative Seed System Approaches. We investigate the merits of these approaches as alternative and complementary pathways for enhancing farmers’ access to crop diversity. Finally, we discuss challenges related to scale, sustainability and legal frame conditions and point out opportunities to realize synergies to achieve the ultimate goal of the ex situ conservation agenda and the farmers’ rights agenda, namely to strengthen farmers’ access to suitable seeds.     

Tar sand occurrence: Implications on hydrocarbon exploration in the offshore Benin Basin

The Benin Basin, just like other marginal basins in the Gulf of Guinea, evolved in the Cretaceous following the opening of the Atlantic. These other basins have recorded significant oil and gas discoveries offshore unlike the Benin Basin that has records of only large tar sand deposits onshore. A review of key play elements of the basin is carried out to assess the possible occurrence of oil and gas in its offshore part. The basin holds a high prospect for both oil and gas in the offshore with the oil kitchens probably occurring within the lower to upper Cretaceous sediments. Besides containing shales deposited during the world-wide Turonian anoxic event that could serve as source rock, the Turonian sequences also have shelf to slope deposits, which are likely to be turbidite of deep-water environments. These turbidites could serve as an excellent reservoir in the basin. Several thick shale sequences within the Cretaceous to Tertiary could provide enough seal for hydrocarbons. In addition, unconformity surfaces marked by reflection terminations that are very significant during pre-drift and syn-rift tectono-stratigraphic development of the basin point to existence of stratigraphic traps in the basin. Concentration of these petroleum elements within the Cretaceous sequences suggest that exploration efforts should be geared toward the Cretaceous, particularly the Turonian sequences in the basin.     

Freeze Concentratton by Layer Crystallization

Layer crystallization in laminar falling films has been studied for freeze concentration applications. A binary mixture of water and sucrose has been tested in order to compare with literature results from suspension crystallizers. The concentration of sucrose in ice, which is a measure for loss of solute. were from 0.4 to 26.5% for bulk concenwlions of sucrose of 5 to 40%. respectively. The time averaged ice growth rates varied from 3. l0-7 l0 3-10-6 m/s. The results are related to expressions for maximum ice growth rate developed from the gradient criteria. Also an expression for maximum ice growth rate from irreversible thermodvnamics is oresented. Althoueh the exwrimental results show that one-step layercrystallization has amuch lower separation effect than suspension crystallizers with washcolumns, multistep layer crystallization could provide an economical favourable freeze concentration process. A multistep process that combines freeze concentration and reverse osmosis is proposed. A case study shows that it is possibleto reduce the investment costs to less than half of existing processes, for dewatering capacity of 700kg per hour. The energy consumption is also reduced.     

Characterization of Ni–Ti Alloy Powders for Use in Additive Manufacturing

Additive manufacturing (AM) offers a fully integrated fabrication solution within many engineering applications. Particularly, it provides attractive processing alternatives for nickel-titanium (Ni–Ti) alloys to overcome traditional manufacturing challenges through layer by layer approach. Among powder-based additive manufacturing processes, the laser beam melting (LBM) and the electron beam melting (EBM) are two promising manufacturing methods for Ni–Ti shape memory alloys. In these methods, the physical characteristics of the powder used as raw material in the process have a significant effect on the powder transformation, deposition, and powder-beam interaction. Thus, the final manufactured material properties are highly affected by the properties of the powder particles. In this study, the Ni?Ti powder characteristics are investigated in terms of particle size, density, distribution and chemical properties using EDS, OM, and SEM analyses in order to determine their compatibility in the EBM process. The solidification microstructure, and after built microstructure are also examined for the gas atomized Ni–Ti powders.     

Comparative study between Phragmites australis root and rhizome extracts for mediating gold nanoparticles synthesis and their medical and environmental applications

In this research, we adopt an ecofriendly and sustainable approach to compare the potentiality and efficiency of Phragmites australis aqueous extracts of two different organs to fabricate gold nanoparticles (AuNPs). The aqueous extracts of plant roots and rhizome were used as alternative reducing agents to conventional chemicals. Various Characterization techniques were used; UV–Vis spectroscopy, Zeta potential, Fourier Transform Infrared Spectroscopy (FT-IR), X-ray diffraction (XRD), Selected Area Electron Diffraction (SAED), Energy Dispersive X-ray Spectroscopy (EDX), High Resolution Transmission Electron Microscopy (HRTEM) equipped with elemental mapping in order to confirm the formation of zero-valent AuNPs, X-ray photoelectron spectroscopy (XPS). Our results demonstrated that both extracts of Phragmites australis are good candidates for the green-synthesis of AuNPs. Zeta potential was used to confirm the stability of AuNPs. The cytotoxic capacities of both AuNPs samples were validated using MTT assay which proved the inhibition of the growth and proliferation of human lung cancer cells (A549 cell line). Antioxidant potentialities were >10%. The phytosynthesized AuNPs exhibited high capacity in removing methylene blue and methyl orange dyes within just one min. This research offers an alternative solution to manage the accumulated unwanted biomass of a widely distributed aquatic macrophyte in aquatic ecosystems.     

Control of a wind farm with an internal direct current collection grid

For a high‐voltage, direct current connected wind farm, an internal direct current (DC) collection grid is a possible further development that can reduce the weight of the transformers significantly, with average losses for the DC system of 3%. For the internal DC grid, the DC/DC converters control the power flow and thereby also the voltages. In this paper, the control of the DC/DC converters in the wind farm is investigated in detail. The control strategy is presented, and suitable time constants are chosen depending on the switching frequency of the converters. Also, the required capacitor size to keep the voltage variations within 5% of the rated value in the case without communication within the wind farm is derived. It is shown that the control is stable and can handle faults on the external grid without any communication within the wind farm. Copyright © 2011 John Wiley & Sons, Ltd.