Surficial sediment texture database for the south-western Iberian Atlantic margin

Assessing the impact of changes on the environment driven by natural or anthropogenic forcers includes the comparison between antecedent and post-event conditions. The latter is particularly relevant in order to better understand to which extent those changes actually impact or alter a particular environment and associated services and to determine the resilience of a system. In this regard, it becomes essential to create or provide databases to inform about baseline conditions. Here, we present a database that integrates surficial sediment samples collected and analysed for textural characterization within the framework of a series of research projects over circa 20 years. Collected samples along the south-western Atlantic margin of the Iberian Peninsula extend from estuaries and beaches to the adjacent continental shelf. For the case of the more dynamic environments, namely coastal sandy barriers, samples were repeated over time in order to capture the intrinsic variability of the system. Examples of the utility of this data set for a variety of purposes and environments are also included within this paper through three examples. Therefore, here we show the added value of the database as it can be used to assess the impact of a particular event or activity at an estuary by providing baseline conditions, evaluate the continental shelf sediment suitability for nourishment activities, or contribute to the understanding of the morphodynamics and classification of beaches. Finally, it is worth stating the importance of such databases to analyse medium- to long-term variability as the one induced by sea level rise, changes in storminess, or human activities.FCT Investigator programme [IF/01047/2014]info:eu-repo/semantics/publishedVersio

Classe de Ciências

info:eu-repo/semantics/publishedVersio

Nitrite reduction by xanthine oxidase family enzymes: a new class of nitrite reductases

J Biol Inorg Chem (2011) 16:443–460 DOI 10.1007/s00775-010-0741-zMammalian xanthine oxidase (XO) and Desulfovibrio gigas aldehyde oxidoreductase (AOR) are members of the XO family of mononuclear molybdoenzymes that catalyse the oxidative hydroxylation of a wide range of aldehydes and heterocyclic compounds. Much less known is the XO ability to catalyse the nitrite reduction to nitric oxide radical (NO). To assess the competence of other XO family enzymes to catalyse the nitrite reduction and to shed some light onto the molecular mechanism of this reaction, we characterised the anaerobic XO- and AORcatalysed nitrite reduction. The identification of NO as the reaction product was done with a NO-selective electrode and by electron paramagnetic resonance (EPR) spectroscopy. The steady-state kinetic characterisation corroborated the XO-catalysed nitrite reduction and demonstrated, for the first time, that the prokaryotic AOR does catalyse the nitrite reduction to NO, in the presence of any electron donor to the enzyme, substrate (aldehyde) or not (dithionite). Nitrite binding and reduction was shown by EPR spectroscopy to occur on a reduced molybdenum centre. A molecular mechanism of AOR- and XO-catalysed nitrite reduction is discussed, in which the higher oxidation states of molybdenum seem to be involved in oxygen-atom insertion, whereas the lower oxidation states would favour oxygenatom abstraction. Our results define a new catalytic performance for AOR—the nitrite reduction—and propose a new class of molybdenum-containing nitrite reductases. Keywords Nitrite reduction Nitric oxide formation Molybdenum Xanthine oxidase Aldehyde oxidoreductase Abbreviations AOR Aldehyde oxidoreductase DMSOR Dimethylsulfoxide reductase EPR Electron paramagnetic resonance Fe/S Iron–sulfur centre Fe/S–NO Dinitrosyl–iron–sulfur complex (MGD)2–Fe Ferrous complex of di(N-methyl-Dglucamine dithiocarbamate)(MGD)2–Fe–NO Mononitrosyl–iron complex Mo-enzymes Pterin–molybdenum-containing enzymes NaR Nitrate reductases NO Nitric oxide radical SO Sulfite oxidase XO Xanthine oxidase Introduction Molybdenum is present in a wide variety of enzymes, in both prokaryotes and eukaryotes, where it performs catalyti

Coastal Dune Restoration: Trends and Perspectives

Sandy coasts are distributed worldwide and they are all heterogeneous ecosystems in terms of morphology, vegetation, and dynamics. Psammophytes are common in these environments. Besides these widespread attributes, sandy beaches and coastal dunes also share the intense impact of humans. Because of their privileged location at the coast, they are preferred sites for urban and maritime development, destinations for tourists, and locations for many other human activities. Thus, over the years (but especially during the last few decades) many of the previously natural dunescapes have been lost to urban, tourist, and industrial developments. Furthermore, a recurring problem of many coastal dune systems is over-stabilization, which is mostly the result of human actions. The urgent need to preserve the natural and valuable coastal dune remnants and, as much as possible, restore those that have been degraded, is evident. There are many different and contrasting actions that have been followed during restoration activities. Restoration actions have involved “soft” methods, such as sand fences, and “hard” methods, such as geotubes and herbicides. Also, restoration may lead not only to the stabilization of dunes, but also to the re-mobilization of sand. On n overcrowded planet where the coasts are ecosystems to which humans gravitate, conservation and restoration actions become exponentially important

Arbuscular Mycorrhizal Symbiosis Limits Foliar Transcriptional Responses to Viral Infection and Favors Long-Term Virus Accumulation

Tomato (Solanum lycopersicum) can establish symbiotic interactions with arbuscular mycorrhizal (AM) fungi, and can be infected by several pathogenic viruses. Here, we investigated the impact of mycorrhization by the fungus Glomus mosseae on the Tomato spotted wilt virus (TSWV) infection of tomato plants by transcriptomic and hormones level analyses. In TSWV-infected mycorrhizal plants, the AM fungus root colonization limited virus-induced changes in gene expression in the aerial parts. The virus-responsive upregulated genes, no longer induced in infected mycorrhizal plants, were mainly involved in defense responses and hormone signaling, while the virus-responsive downregulated genes, no longer repressed in mycorrhizal plants, were involved in primary metabolism. The presence of the AM fungus limits, in a salicylic acid-independent manner, the accumulation of abscissic acid observed in response to viral infection. At the time of the molecular analysis, no differences in virus concentration or symptom severity were detected between mycorrhizal and nonmycorrhizal plants. However, in a longer period, increase in virus titer and delay in the appearance of recovery were observed in mycorrhizal plants, thus indicating that the plant's reaction to TSWV infection is attenuated by mycorrhization. </jats:p

The Profile of Executive Secretaries and Their Relationship with Labor Demands

The work shows an analysis related to the emergence of the profession of the executive secretariat, highlighting the importance of the functions performed by the people who occupy these positions, for the good performance of public and private institutions. The results of an investigation carried out in the GAD of the Portoviejo canton, of the province of Manabí in Ecuador, are presented, where the current performance of a group of people in the position of the executive secretariat is evaluated, where the positive evolution is shown. It has been experienced in the last years in the exercise of this profession in correspondence with the labor demands of the Autonomous Decentralized Government of the canton Portoviejo

Equity Commitment under Uncertainty: A Hierarchical Model of Real Option Entry Mode Choices

We develop a real option hierarchical model of entry mode choice and test predictions using a sample of US companies in Latin America and the Caribbean between 1980 and 2005. Probit results indicate that the choice between a real option non-equity mode and equity commitment is influenced by previous acquisition experience, R&D and advertising intensities, and country risk. The choice of the more flexible real option JV mode over WOEs is positively related to greater firm size and market-to-book ratio in countries with better infrastructure. In contrast, greater marketing intensity and lower country risk encourage WOEs