Diversidad liquénica asociada a fenómenos post-incendio en los alcornocales valenciano-castellonenses.

FOS, S., CALATAYUD, A. & BARRENO, E. 2001. Diversidad liquénica asociada a fenómenos post-incendio en los alcornocales valenciano-castellonenses. Bot. Complutensis 25: 103-113. Se estudia la colonización post-incendio de las cortezas quemadas de los alcornoques (Quercus suber L.), por líquenes epífitos,en los diferentes núcleos del alcornocal valenciano-castellonense (Asplenio onopteridis-Querco suberis sigmetum). Estos bosques, afectados por incendios diferentes, se localizan en las Sierras de Espadán y Calderona y en el Desierto de las Palmas y difieren en sus condiciones bioclimáticas, en la estructura del bosque y, consecuentemente, en la composición florística de las comunidades previas a los incendios. El objetivo de este trabajo es conocer el estado de la recolonización e identificar que factores podrían estar implicados en el proceso. La riqueza específica y la cobertura de las comunidades epífitas muestra asimetrías importantes entre áreas. Estas diferencias se relacionan con la proximidad de zonas inalteradas, que deben actuar como inóculo, y con las características bioclimáticas de cada territorio. En total, se han identificado 40 especies liquénicas: 18 crustáceas (45%), 18 foliáceas (45%) y 4 fruticulosas (10%). La sucesión secundaria está dominada por especies de amplia tolerancia ecológica que poseen estructuras de multiplicación vegetativa. Hyperphyscia adglutinata, Physcia adscendens, Ph. tenella y Scoliciosporum chloroccocum son las que aparecen más tempranamente y las más ampliamente representadas; otras, como Evernia prunastri, P. tiliacea, P. soredians,P. subrudecta, Ramalina farinacea, etc., aparecen con mayor frecuencia y desarrollo en los alcornocales que sufrieron un incendio menos intenso y con ombroclima subhúmedo.FOS, S., CALATAYUD, A. & BARRENO, E. 2001. Lichen diversity associated with post-fire colonization in the Valenciano-castellonense cork-oak forests. Bot. Complutensis 25: 103113. 103 Simón Fos et al. Diversidad liquénica asociada a fenómenos post-incendio... The post-fire colonization of the burned barks of cork-oaks (Quercus suber L.) by epiphytic lichens affected by fire episodes has been studied in different areas of the Valenciano-castellonense cork-oak forests (Asplenio onopteridis-Querco suberis sigmetum). These forests, which have been affected by fires of different intensity, are located in Espadán and Calderona mountains and in the Desierto de Las Palmas and differ with respect to their bioclimate and forest structure. This facts result in a different floristic composition of the epiphytic communities prior to the occurrence of fires. The aim of this paper is to determine the recolonization state and to identify the factors involved in the process. Specific richness and coverage of the epiphytic communities show differences between areas. These differences are related with the proximity to undisturbed areas and with its bioclimatic characteristics. 40 species have been identified: 18 crustose (45%), foliose (45%) and 4 fruticose lichens (10%). Secondary succession is dominated by species with wide ecological tolerance with soredia or isidia. Hyperphyscia adglutinata, Physcia adscendens, Ph. tenella and Scoliciosporum chloroccocum show the greatest colonization success; others, such as Evernia prunastri, P. tiliacea, P. soredians, P. subrudecta, Ramalina farinacea, etc., show higher frequency and thallus development in forests which were affected by less intense fires and with subhumid ombroclimate

On the rejection and reversibility of fouling in ultrafiltration as assessed by hydraulic impedance spectroscopy

[EN] The manifestation of critical fluxes in membrane filtration has typically served to set an upper value above which detrimental fouling events and a substantial increase of membrane resistance occurs. Despite the usefulness of critical flux concepts for conducting sustainable membrane processes, the specific phenomena causing them cannot be easily identified via conventional membrane filtration modes. Usually arbitrary fouling rates are selected to delimit the boundary between under- and over-critical flux operation. Timescales respective for colloidal matter accumulation are overlooked. Frequency response analysis of transmembrane pressures has been recently presented as a highly-sensitive method to track fouling in ultrafiltration. This hydraulic impedance spectroscopy method allows not only measuring membrane resistances but also corresponding time constants related to colloidal matter accumulation. In this work, hydraulic impedance spectra are gained for the ultrafiltration of different model foulants to assess the origin of critical fluxes for two different membranes. A correlation among characteristic impedance features and the type of fouling could be established: the evolution of phase shift between flux and pressure at increasing fluxes allows identifying the formation of external fouling layers, while registering of hysteresis loops at reversed frequency sequences signals the development of irreversible internal fouling. The hydraulic impedance method emerges as a precise and more sensitive monitoring tool to diagnose the beginning and nature of critical fouling.M.W. acknowledges the support through an Alexander-von-Humboldt Professorship. M.C. Marti-Calatayud is grateful for the funding received from the Generalitat Valenciana (APOSTD/2017/059). M.C. Marti-Calatayud also appreciates the helpful suggestions received by Tao Luo and Georg Linz, as well as the fruitful discussions with Sarah Armbruster. This work was supported by the German Federal Ministry of Education and Research (BMBF) through the project BRAMAR (02WCL1334A). We thank Synder Filtration for the supplied membranes.Martí Calatayud, MC.; Schneider, S.; Wessling, M. (2018). On the rejection and reversibility of fouling in ultrafiltration as assessed by hydraulic impedance spectroscopy. Journal of Membrane Science. 564:532-542. https://doi.org/10.1016/j.memsci.2018.07.021S53254256

Interplay between physical cleaning, membrane pore size and fluid rheology during the evolution of fouling in membrane bioreactors

[EN] Fouling is one of the most pressing limitations during operation of membrane bioreactors, as it increases operating costs and is the cause of short membrane lifespans. Conducting effective physical cleanings is thus essential for keeping membrane operation above viable performance limits. The nature of organic foulants present in the sludge and the membrane properties are among the most influential factors determining fouling development and thus, efficiency of fouling mitigation approaches. The role of other factors like sludge viscosity on fouling is still unclear, given that contradictory effects have been reported in the literature. In the present study we use a new research approach by which the complex interplay between fouling type, levels of permeate flux, membrane material and feed properties is analyzed, and the influence of these factors on critical flux and membrane permeability is evaluated. A variety of systems including activated sludge and model solutions with distinct rheological behavior has been investigated for two membranes differing in pore size distribution. We present a novel method for assessing the efficiency of fouling removal by backwash and compare it with the efficiency achieved by means of relaxation. Results obtained have proven that backwash delays development of critical fouling as compared with relaxation and reduces fouling irreversibility regardless of fluid rheology. It was shown that backwash is especially effective for membranes for which internal fouling is the main cause of loss in permeability. Nonetheless, we found out that for membranes with tight pores, both relaxation and backwash are equally effective. The critical flux decreases significantly for high-viscosity fluids, such as activated sludge. This effect is mainly caused by an intensified concentration polarization at the feed side rather than by internal fouling events. However, membrane permeability has been proven to rely more on the permeate viscosity than on the feed viscosity: poor rejection of organic fractions showcasing high viscosity causes an acute decline in membrane permeability as a consequence of increased shear stress inside the membrane pores. (C) 2018 Elsevier Ltd. All rights reserved.M.W. acknowledges the support through an Alexander-von-Humboldt Professorship. M.C. Marti-Calatayud acknowledges the support to Generalitat Valenciana through the funding APOSTD2017. M.C. Marti-Calatayud thanks the contributions of Sybille Hanisch, Sanchita Khandelwal and Sara Vivanco. This work was supported by the German Federal Ministry of Education and Research (BMBF) through the project BRAMAR (02WCL1334A). We thank Synder Filtration for the supplied membranesMartí Calatayud, MC.; Schneider, S.; Yüce, S.; Wessling, M. (2018). Interplay between physical cleaning, membrane pore size and fluid rheology during the evolution of fouling in membrane bioreactors. Water Research. 147:393-402. https://doi.org/10.1016/j.watres.2018.10.017S39340214

Device for data-acquisition from transient signals: kinetic considerations

This paper reports on the evaluation and testing of a home-made device. Data-acquisition, treatment of transient signals and the hardware and software involved are discussed. Some practical aspects are developed in order to power the autonomy of procedures using the device. Kinetic and multi-signal calculations are considered in order to cover the actual tendencies in continuous-flow analysis. Somepractical advantages versus the use of classical chart recorders or commercial computerized-instrument devices are pointed out

Directed Molecular Stacking for Engineered Fluorescent Three-Dimensional Reduced Graphene Oxide and Coronene Frameworks

[EN] Three‐dimensional fluorescent graphene frameworks with controlled porous morphologies are of significant importance for practical applications reliant on controlled structural and electronic properties, such as organic electronics and photochemistry. Here we report a synthetically accessible approach concerning directed aromatic stacking interactions to give rise to new fluorogenic 3D frameworks with tuneable porosities achieved through molecular variations. The binding interactions between the graphene‐like domains present in the in situ‐formed reduced graphene oxide (rGO) with functional porphyrin molecules lead to new hybrids via an unprecedented solvothermal reaction. Functional free‐base porphyrins featuring perfluorinated aryl groups or hexyl chains at their meso‐ and β‐positions were employed in turn to act as directing entities for the assembly of new graphene‐based and foam‐like frameworks and of their corresponding coronene‐based hybrids. Investigations in the dispersed phase and in thin‐film by XPS, SEM and FLIM shed light onto the nature of the aromatic stacking within functional rGO frameworks (denoted rGOFs) which was then modelled semi‐empirically and by DFT calculations. The pore sizes of the new emerging reduced graphene oxide hybrids are tuneable at the molecular level and mediated by the bonding forces with the functional porphyrins acting as the “molecular glue”. Single crystal X‐ray crystallography described the stacking of a perfluorinated porphyrin with coronene, which can be employed as a molecular model for understanding the local aromatic stacking order and charge transfer interactions within these rGOFs for the first time. This opens up a new route to controllable 3D framework morphologies and pore size from the Ångstrom to the micrometre scale. Theoretical modelling showed that the porosity of these materials is mainly due to the controlled inter‐planar distance between the rGO, coronene or graphene sheets. The host‐guest chemistry involves the porphyrins acting as guests held through π‐π stacking, as demonstrated by XPS. The objective of this study is also to shed light into the fundamental localised electronic and energy transfer properties in these new molecularly engineered porous and fluorogenic architectures, aiming in turn to understand how functional porphyrins may exert stacking control over the notoriously disordered local structure present in porous reduced graphene oxide fragments. By tuning the porosity and the distance between the graphene sheets using aromatic stacking with porphyrins, it is also possible to tune the electronic structure of the final nanohybrid material, as indicated by FLIM experiments on thin films. Such nanohybrids with highly controlled pores dimensions and morphologies open the way to new design and assembly of storage devices and applications incorporating π‐conjugated molecules and materials and their π‐stacks may be relevant towards selective separation membranes, water purification and biosensing applications.S.I.P. and S.W.B. thank The Royal Society and STFC for funding. B.Y.M. thanks the University of Bath for a studentship (ORS). D.G.C. thanks the Fundación General CSIC for funding (ComFuturo Program). Dr. Jose A. Ribeiro Martins, Professors Jeremy K. M. Sanders and Paul Raithby are acknowledged for training, helpful discussions and porphyrin supramolecular chemistry. The S.I.P. group thanks the EPSRC for funding to the Centre of Graphene Science (EP/K017160/1) and to the Centre for Doctoral Training in Sustainable Chemical Technologies (EP/L016354/1). The authors thank EPSRC National Service for Mass Spectrometry at Swansea and EPSRC National Service for Crystallography at Southampton for data collection. The authors also acknowledge the ERC for the Consolidator Grant O2SENSE (617107, 2014–2019)

Understanding mountain soils : a contribution from mountain areas to the International Year of Soils 2015

Smallholder farmers in the Taita hills and Mount Kilimanjaro recognize the need to conserve soil nutrients of fields and farms located in the upper, middle and lower zones of mountainous areas. These mountain communities depend on rain-fed subsistence agriculture which means that for sustainable subsistence crop production, they also depend on nutrient availability and use efficiency in farming households. A study under way in the area has looked at loss of land cover and infestations of plant pests and diseases and is using this information to raise farmers’ awareness of soil fertility and to introduce best cropping practices

Unraveling graft compatibility of scion/rootstock interactions in pepper

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Influence of temperature on intra- and interspecific resource utilization within a community of lepidopteran maize stemborers

Competition or facilitation characterises intra-and interspecific interactions within communities of species that utilize the same resources. Temperature is an important factor influencing those interactions and eventual outcomes. The noctuid stemborers, Busseola fusca and Sesamia calamistis and the crambid Chilo partellus attack maize in sub-Saharan Africa. They often occur as a community of interacting species in the same field and plant at all elevations. The influence of temperature on the intra-and interspecific interactions among larvae of these species, was studied using potted maize plants exposed to varying temperatures in a greenhouse and artificial stems kept at different constant temperatures (15 degrees C, 20 degrees C, 25 degrees C and 30 degrees C) in an incubator. The experiments involved single-and multispecies infestation treatments. Survival and relative growth rates of each species were assessed. Both intra-and interspecific competitions were observed among all three species. Interspecific competition was stronger between the noctuids and the crambid than between the two noctuids. Temperature affected both survival and relative growth rates of the three species. Particularly at high temperatures, C. partellus was superior in interspecific interactions shown by higher larval survival and relative growth rates. In contrast, low temperatures favoured survival of B. fusca and S. calamistis but affected the relative growth rates of all three species. Survival and relative growth rates of B. fusca and S. calamistis in interspecific interactions did not differ significantly across temperatures. Temperature increase caused by future climate change is likely to confer an advantage on C. partellus over the noctuids in the utilization of resources (crops)

Synthesis and electrochemical behavior of ceramic cation-exchange membranes based on zirconium phosphate

Cation-exchange membranes made exclusively from ceramic materials have been synthesized by means of the impregnation of microporous ceramic supports with zirconium phosphate. Changes in the pore size distribution and total pore volume of the supports were provoked by the addition of starch as pore former in the fabrication procedure. This allowed the production of supports with increased effective electrical conductivities and with larger pores available for the zirconium phosphate deposition. An improved functionality for the exchange of cations was given to the ceramic membranes by means of their impregnation with the active particles of zirconium phosphate. The ion-exchange properties of the membranes were increased with further impregnation cycles and the resulting current voltage curves showed a similar shape to that typical of commercial polymeric ion-exchange membranes. The production of ionexchange membranes with increased chemical and radiation stability will broaden their applicability for the treatment of specific industrial waste waters, which are very aggressive for the current commercial ion-exchange membranes.Manuel-Cesar Marti-Calatayud wants to express his gratitude to Universitat Politecnica de Valencia for a postgraduate grant (Ref. 2010-12). S. Sales would like to express her gratitude to Ministerio de Ciencia e Investigacion (Spain) for a postgraduate grant (AP2009-4409). This work was supported by Ministerio de Ciencia e Innovacion (Spain) with the project numbers CTQ2008-06750-C02-01/PPQ and CTQ2008-06750-C02-02/PPQ.Martí Calatayud, MC.; García Gabaldón, M.; Pérez-Herranz, V.; Sales, S.; Mestre, S. (2013). Synthesis and electrochemical behavior of ceramic cation-exchange membranes based on zirconium phosphate. Ceramics International. 39(4):4045-4054. https://doi.org/10.1016/j.ceramint.2012.10.255S4045405439