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Critical transitions in Chinese dunes during the past 12,000 years
No full textDune systems can have alternative stable states that coexist under certain environmental conditions: a vegetated, stabilized state and a bare active state. This behavior implies the possibility of abrupt transitions from one state to another in response to gradual environmental change. Here, we synthesize stratigraphic records covering 12,000 years of dynamics of this system at 144 localities across three dune fields in northern China. We find side-by-side coexistence of active and stabilized states, and occasional sharp shifts in time between those contrasting states. Those shifts occur asynchronously despite the fact that the entire landscape has been subject to the same gradual changes in monsoon rainfall and other conditions. At larger scale, the spatial heterogeneity in dune dynamics averages out to produce relatively smooth change. However, our results do show different paths of recovery and collapse of vegetation at system-wide scales, implying that hysteretic behavior occurs in spatially extended systems.</p
Natural Variation in Portuguese Common Bean Germplasm Reveals New Sources of Resistance Against Fusarium oxysporum f. sp. phaseoli and Resistance-Associated Candidate Genes
No full textCommon bean (Phaseolus vulgaris) is one of the most consumed legume crops in the world, and Fusarium wilt, caused by the fungus Fusarium oxysporum f. sp. phaseoli, is one of the major diseases affecting its production. Portugal holds a very promising common bean germplasm with an admixed genetic background that may reveal novel genetic resistance combinations between the original Andean and Mesoamerican gene pools. To identify new sources of Fusarium wilt resistance and detect resistance-associated single-nucleotide polymorphisms (SNPs), we explored, for the first time, a diverse collection of the underused Portuguese common bean germplasm by using genome-wide association analyses. The collection was evaluated for Fusarium wilt resistance under growth chamber conditions, with the highly virulent F. oxysporum f. sp. phaseoli strain FOP-SP1 race 6. Fourteen of the 162 Portuguese accessions evaluated were highly resistant and 71 intermediate. The same collection was genotyped with DNA sequencing arrays, and SNP-resistance associations were tested via a mixed linear model accounting for the genetic relatedness between accessions. The results from the association mapping revealed nine SNPs associated with resistance on chromosomes Pv04, Pv05, Pv07, and Pv08, indicating that Fusarium wilt resistance is under oligogenic control. Putative candidate genes related to phytoalexin biosynthesis, hypersensitive response, and plant primary metabolism were identified. The results reported here highlight the importance of exploring underused germplasm for new sources of resistance and provide new genomic targets for the development of functional markers to support selection in future disease resistance breeding programs.</p
Defining the solution space to accelerate climate change adaptation
No full textDecision makers need better insights about solutions to accelerate adaptation efforts. Defining the concept of solution space and revealing the forces and strategies that influence this space will enable decision makers to define pathways for adaptation action. [Figure not available: see fulltext.].</p
Effect of storage conditions on the physicochemical properties of infant milk formula powders containing different lactose-to-maltodextrin ratios
No full textThis study investigated the effect of storage parameters on the physicochemical changes of spray-dried infant milk formula (IMF) powders prepared with various lactose-to-maltodextrin (L:M) ratios (L:M 100:0, L:M 85:15 and L:M 70:30). Powders were characterized during 180 days of storage at 22 and 40 °C and relative humidity (RH) of 11, 23 and 54%. IMF powders were found mostly stable at both temperatures up to 23RH. Deteriorative physicochemical changes were observed at 54RH which were more rapid at 40 °C than at 22 °C. Increasing temperature and RH during storage decreased the glass transition temperature (Tg) to 40%. Surface fat content, degree of aggregation and caking increased during storage. Increased surface fat was accompanied by a decrease in surface protein and carbohydrate contents. Incorporation of maltodextrin increased the Tg, decreased the crystallinity and improved the stability of powders.</p
The physics of microemulsions extracted from modeling balanced tensionless surfactant-loaded liquid-liquid interfaces
No full textMicroemulsions are explored using the self-consistent field approach. We consider a balanced model that features two solvents of similar size and a symmetric surfactant. Interaction parameter χ and surfactant concentration φsb complement the model definition. The phase diagram in χ-φsb coordinates is known to feature two lines of critical points, the Scott and Leibler lines. Only upon imposing a finite distance between the interfaces, we observe that the Scott line meets the Leibler line. We refer to this as a Lifshitz point (LP) for real systems. We add regions that are relevant for microemulsions to this phase diagram by considering the saturation line, which connects (χ, φsb)-points for which the interface becomes tensionless. Crossing this line implies a first-order phase transition as internal interfaces develop, characteristic for one-phase microemulsions. The saturation line ends at the so-called microemulsion point (MP). The MP is shown to connect with the LP by a line of MP-like critical points, found by searching for a "MP" while the distance between interfaces is fixed. A pair of binodal lines that envelop the three-phase (Winsor III) microemulsion region is shown to connect to the MP. The cohesiveness of the middle phase in Winsor III is related to non-monotonic, inverse DLVO-type interaction curves between the surfactant-loaded tensionless interfaces. The mean and Gaussian bending modulus, relevant for the shape fluctuations and the topology of interfaces, respectively, are evaluated along the saturation line. Near the MP, both rigidities are positive and vanish in a power-law fashion with coefficient unity at the MP. Overseeing these results proves that the MP has a pivoting role in the physics of microemulsions.</p
Harvesting time and biomass composition affect the economics of microalgae production
No full textCost simulations provide a strong tool to render the production of microalgae economically viable. This study evaluated the unexplored effect of harvesting time and the corresponding microalgal biomass composition on the overall production cost, under both continuous light and light/dark regime using techno-economic analysis (TEA). At the same time, the TEA gives evidence that a novel product “proteinaceous salt” from Dunaliella microalgae production is a promising high-value product for commercialization with profitability. The optimum production scenario is to employ natural light/dark regime and harvest microalgal biomass around late exponential phase, obtaining the minimum production cost of 11 €/kg and a profitable minimum selling price (MSP) of 14.4 €/kg for the “proteinaceous salt”. For further optimization of the production, increasing microalgal biomass concentration is the most effective way to reduce the total production cost and increase the profits of microalgae products.</p
Oxidative stability of soy proteins: From ground soybeans to structured products
No full textThe production of soy protein-based foods requires multiple-step, intensive processing and storage of soy ingredients, which can increase the product's susceptibility to oxidation. Therefore, we investigated the oxidative stability of soy protein-based products subjected to different relevant conditions or treatments: over storage of soy flours, over fractionation to yield soy protein isolate (SPI), and over subsequent thermomechanical processing to yield a model structured product. Soy flours were stable to lipid and protein oxidation over 250 days storage in chilled or ambient conditions. The fractionation process applied to make SPI did not increase substantially protein carbonylation, but increased surface-exposed hydrophobicity and decreased free thiols, compared to the starting defatted flour. Subsequent processing of hydrated SPI powder at 140 °C further increased protein carbonylation to a high extent. Therefore, we conclude that soy flours can be stable over long storage times, but processing to yield structured foods products promote protein oxidation.</p
Limonene nanoemulsified with soya lecithin reduces the intensity of non-isothermal treatments for inactivation of Listeria monocytogenes
No full textConsumers’ demands for ready-to-eat, fresh-like products are on the rise during the last years. This type of products have minimal processing conditions that can enable the survival and replication of pathogenic microorganisms. Among them, Listeria monocytogenes is of special concern, due to its relatively high mortality rate and its ability to replicate under refrigeration conditions. Previous research works have shown that nanoemulsified essential oils in combination with thermal treatments are effective for inactivating L. monocytogenes. However, previous research works were limited to isothermal conditions, whereas actual processing conditions in industry are dynamic. Under dynamic conditions, microorganism can respond unexpectedly to the thermal stress (e.g. adaptation, acclimation or increased sensitivity). In this work, we assess the combination of nanoemulsified D-limonene with thermal treatments under isothermal and dynamic conditions. The nanoemulsion was prepared following an innovative methodology using soya lecithin, a natural compound as well as the essential oil. Under isothermal heating conditions, the addition of the antimicrobial enables a reduction of the treatment time by a factor of 25. For time-varying treatments, dynamic effects were relevant. Treatments with a high heating rate (20 °C/min) are more effective than those with a slow heating rate (1 °C/min). This investigation demonstrates that the addition of nanoemulsified D-limonene can greatly reduce the intensity of the thermal treatments currently applied in the food industry. Hence, it can improve the product quality without impacting its safety.</p
Tilling the earth; modelling global N2O emissions caused by tillage
No full textAgriculture is the largest contributor of non-CO2 anthropogenic greenhouse gas emissions (GHG). Agricultural based mitigation strategies (e.g. no-tillage) are identified to reduce emissions from agricultural soils through improved agricultural management. Global ecosystem models that are usually used for finding the potential of agricultural based mitigation strategies are limited, because processes related to agricultural management are currently underrepresented in global ecosystem models. The aim of this thesis is to contribute to the representation of agricultural management in global ecosystem models, so that the potential of agricultural based mitigation practices can be better quantified. Therefore, this thesis first addressed how processes related to agricultural management can be described in global ecosystem models, with a focus on processes related to tillage and N2O emissions. This analysis resulted in a standardized framework that can be followed to incorporate other agricultural management practices in global ecosystems as well. After indicating how processes related to tillage can be described, they were implemented into the global ecosystem model LPJmL. Subsequently, the extended LPJmL model was evaluated on its performance on various fluxes (including N2O and CO2) at the global scale and for a number of experimental sites. Finally, the uncertainty caused by the upscaling of soil input data when assessing tillage effects on N2O emissions were addressed. LPJmL was not capable of accurately simulating tillage effects on N2O emissions. Hence, the potential of mitigating N2O emissions through tillage management cannot be well assessed. However, the implementation of the more detailed tillage-related mechanism into the global ecosystem model LPJmL improved the ability to understand agricultural management options for agricultural mitigation of CO2 emissions, climate change adaptation and reducing environmental impacts. The work in this thesis concludes that as processes related to agricultural management can be incorporated into global ecosystem models by following the standardized framework, and data-scarcity on agricultural management does not necessarily limit the evaluation of the extended model, there is no general barrier to extend global ecosystem models by modules for the representation of agricultural management
Effective elements of care-physical activity initiatives for adults with a low socioeconomic status: A concept mapping study with health promotion experts
No full textIn care-physical activity (care-PA) initiatives, primary care and sports are combined to stimulate PA among adults at risk of lifestyle related diseases. Preliminary results from Dutch care-PA initiatives for adults with a low socioeconomic status (SES) indicate a decrease in participants’ body weight and an improved quality of life, however, the elements that make these initiatives successful are yet to be identified. In total, 19 Dutch health promotion experts participated in our concept mapping (CM) of the effective elements of care-PA initiatives for adults with a low SES. The experts identified 111 effective elements of these initiatives, which were grouped into 11 clusters, focusing on: 1) approaching participants within the care-PA initiative, 2) barriers experienced throughout the initiative, 3) long-term implementation, 4) customizing the care-PA initiative to the target population, 5) social support, 6) structure and guidance, 7) the professionals within the care-PA initiative, 8) the accessibility of the care-PA initiative, 9) targeted behaviour and progression, 10) recruitment and administration, and 11) intersectoral collaboration. CM was useful for creating a valuable overview of these effective elements. Our results could be used to improve the development and implementation of future care-PA initiatives for adults with a low SES