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La Alberca de Záncara, Spain

Meseguer-Olmo L.,University of Murcia | Aznar-Cervantes S.,IMIDA | Mazon P.,University Miguel Hernandez | De Aza P.N.,University Miguel Hernandez
Journal of Materials Science: Materials in Medicine

This work describes the evaluation of three ceramic materials as potential osteogenic substrate for bone tissue engineering.The capacity of adult humanmesenchymal stem cells cultured under experimental conditions known to adhere, proliferate and differentiate into osteoblasts was studied. Two types of culture medium: growth medium and osteogenic medium were evaluated. The materials were pure α-tricalciumphosphate and also αTCPdoped with either 1.5 or 3 wt% of dicalcium silicate. The results showed that the hMSCs cultured adhered, spread, proliferated and produced mineralized extracellular matrix on all the ceramics studied. They showed an osteoblastic phenotype, especially in the αTCP doped with 1.5 wt% C2S, indicating osteoblastic differentiation as a result of the increased concentration of silicon in solid solution in TCP. Ceramics evaluated in this work are bioactive, cytocompatible and capable of promoting the differentiation of hMSCs into osteoblast. © Springer Science+Business Media, LLC 2012. Source

Evers J.B.,Wageningen University | Vos J.,Wageningen University | Yin X.,Wageningen University | Romero P.,IMIDA | And 2 more authors.
Journal of Experimental Botany

Intimate relationships exist between form and function of plants, determining many processes governing their growth and development. However, in most crop simulation models that have been created to simulate plant growth and, for example, predict biomass production, plant structure has been neglected. In this study, a detailed simulation model of growth and development of spring wheat (Triticum aestivum) is presented, which integrates degree of tillering and canopy architecture with organ-level light interception, photosynthesis, and dry-matter partitioning. An existing spatially explicit 3D architectural model of wheat development was extended with routines for organ-level microclimate, photosynthesis, assimilate distribution within the plant structure according to organ demands, and organ growth and development. Outgrowth of tiller buds was made dependent on the ratio between assimilate supply and demand of the plants. Organ-level photosynthesis, biomass production, and bud outgrowth were simulated satisfactorily. However, to improve crop simulation results more efforts are needed mechanistically to model other major plant physiological processes such as nitrogen uptake and distribution, tiller death, and leaf senescence. Nevertheless, the work presented here is a significant step forwards towards a mechanistic functional-structural plant model, which integrates plant architecture with key plant processes. © 2010 The Author. Source

Perez-Perez J.G.,IMIDA | Dodd I.C.,Lancaster University
Journal of Experimental Botany

Previous studies with partial rootzone drying (PRD) irrigation demonstrated that alternating the wet and dry parts of the rootzone (PRD-Alternated) increased leaf xylem ABA concentration ([X-ABA]leaf) compared with maintaining the same wet and dry parts of the rootzone (PRD-Fixed). To determine the relative contributions of different parts of the rootzone to this ABA signal, [X-ABA]leaf of potted, split-root tomato (Solanum lycopersicum) plants was modelled by quantifying the proportional water uptake from different soil compartments, and [X-ABA]leaf responses to the entire pot soil-water content (θpot). Continuously measuring soil-moisture depletion by, or sap fluxes from, different parts of the root system revealed that water uptake rapidly declined (within hours) after withholding water from part of the rootzone, but was rapidly restored (within minutes) upon re-watering. Two hours after re-watering part of the rootzone, [X-ABA]leaf was equally well predicted according to θpot alone and by accounting for the proportional water uptake from different parts of the rootzone. Six hours after re-watering part of the rootzone, water uptake by roots in drying soil was minimal and, instead, occurred mainly from the newly irrigated part of the rootzone, thus [X-ABA]leaf was best predicted by accounting for the proportional water uptake from different parts of the rootzone. Contrary to previous results, alternating the wet and dry parts of the rootzone did not enhance [X-ABA]leaf compared with PRD-Fixed irrigation. Further work is required to establish whether altered root-to-shoot ABA signalling contributes to the improved yields of crops grown with alternate, rather than fixed, PRD. © 2015 © The Author 2015. Published by Oxford University Press on behalf of the Society for Experimental Biology. Source

Garcia J.G.,IMIDA | Garcia B.G.,IMIDA
Aquaculture International

The interest in diversifying aquacultural production with new species is evident, preferably with species with a high commercial value and whose consumption is not geographically limited. In this sense, octopus would be a good choice. The present work, therefore, presents an economic-financial analysis of the commercial viability of octopus ongrowing in the Mediterranean, paying special attention to the one- or two-cycle approach. Viability-profitability equations are developed for analysing economic parameters associated with production. To estimate the investment, an offshore ongrowing installation was designed comprising 150 cages containing 30,000 individuals. Growth was estimated for the two strategies: (A) Two consecutive cycles per year (2CY), each lasting 3.5 months from October to June. Initial weight was 0.7 kg, and the mean final weight was 2.7 kg. (B) One growth cycle per year (1CY) beginning in November or December and finishing in April or May, starting with the same weight individuals (0.7 kg) and giving individuals with a final weight of 3.65 kg. The highest costs, the most important from an economic point of view, are feed (38.57 and 40.03%, respectively), fixed assets (25.26 and 17.47%, respectively), juveniles (16.65 and 23.02%, respectively), and in fourth place salaries (14.34 and 15.60%, respectively). The equations obtained for the variables NPV (Net Present Value) and IRR (Internal Ratio of Return) are the following: 1 cycle per year (1CY), NPV = -489,088 - 1.45 K - 1,439,823 C F - 1,477,890 C J - 1,460,627 C O + 1,432,386 SP, IRR = 0.1328 - 7.82 × 10 -8 K - 0.0416 C F - 0.0437 C J - 0.0427 C O + 0.0412 SP. 2 cycles per year (2CY), NPV = -404,431 - 1.46 K - 2,118,410 C F - 2,121,221 C J - 2,144,755 C O + 2,129,223 SP, and IRR = 0.0952 - 6.95 × 10 -8K - 0.0586 C F - 0.0588 C J - 0.0588 C O + 0.0613 SP. The NPV and IRR values estimated with the econometric equations for each option using the initial variables confirm that 1CY has a higher NPV (3,013,569 €) and IRR (12.27%) than 2CY, with an NPV of 2,396,708 € and IRR of 10.39%. In both cases, octopus ongrowing is economically viable, although 1CY is the most favourable system. © 2011 Springer Science+Business Media B.V. Source

Claret A.,IRTA Food Technology | Guerrero L.,IRTA Food Technology | Gines R.,University of Las Palmas de Gran Canaria | Grau A.,Limia Laboratorio Of Investigaciones Marinas Y Acuicultura | And 4 more authors.

Aquaculture is a food-producing activity, alternative to traditional extractive fishing, which still acts as a reference for most consumers. The main objective of the present paper was to study which consumer beliefs, regarding farmed versus wild fish, hinder the potential development of the aquaculture sector. To achieve this purpose the study was organized into two complementary steps: a qualitative approach (focus groups) aimed at assessing consumer perception about wild and farmed fish and to identify the salient beliefs that differentiate them; and a quantitative approach (survey by means of a questionnaire) to validate the results obtained in the focus group discussions over a representative sample of participants (n = 919). Results showed that participants perceive clear differences between farmed and wild fish. Although no significant differences between both kinds of fish were detected on safety, in general farmed fish was perceived to be less affected by marine pollution, heavy metals and parasites. In the contrary, wild fish was considered to have healthier feeding, to contain fewer antibiotics and to be fresher, healthier, less handled and more natural. Beliefs related to quality were in favour of wild fish, while those related to availability and price were in favour of farmed fish. Significant differences were observed in the perception of both kinds of fish depending on the consumers' objective knowledge about fish, on the level of education, age and gender and on the three segments of consumers identified: "Traditional/Conservative", "Connoisseur", "Open to aquaculture". The results provided could play an important role when planning and designing efficient marketing strategies for promoting farmed fish by adapting the information provided to the perception of each segment of consumers identified by the present study. © 2014 Elsevier Ltd. Source

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