Zircon dating and inheritance of a pre-Variscan granite, SW Iberia

The Portalegre pluton is an aligned series of Pre-Variscan granitoids located along the boundary of the Central Iberian/ Ossa Morena Zones (SW Iberian Massif, Portugal). Singlezircon geochronology (U-Pb SHRIMP and Pb/Pb stepwise evaporation) yield an Upper Cambrian/Lower Ordovician age (492.7 ± 3.5 Ma) interpreted as the magmatic crystallization age. The inherited zircon cores indicate the involvement of sources with a wide range age-components: an important Late Neoproterozoic (548 ± 7 Ma and c. 611-681 Ma) population and a Mesoproterozoic (c. 0.95-1.1 Ga) and older (c. 2.6 Ga) components. Younger zircon ages of 358 ± 36 and 387 ± 7 Ma were also found and interpreted as the record of a Variscan metamorphic event. The presence of Grenvillian zirconforming events in the protholiths of Portalegre granites is significant in the regional geodynamic context of the Iberian Massif (Central Iberian affinity?). At present, the Grenvillian ages are not noticeable in the Late Neoproterozoic/Early Cambrian record of the Ossa-Morena Zone, that has been correlated with West African Craton [1]. These data suggests that the Central Iberian Zone and Ossa-Morena Zone were independent peri-gondwana terrains with diferent paleogeographic affinities before the Ordovician times. The overall chemistry for the Portalegre granites shows they are very differentiated (SiO2=74-76 wt %), peraluminous (A/CNK=1.1–1.4); have low Zr=36-125ppm, Th/Ta=2-10, ΣREE= 22-134 and 1000Ga/Al >3. Their isotopic signatures (87Sr/86Sr)493=0.7050-0.7065, εNd493(-2.88 to -0.85) and δ18O=10.5-10.8‰, are compatible with partial melting of relatively young recycled metaigneous ± enriched mantle sources. The age pattern from the inherited zircon cores in the Portalegre granites shows that the late Neoproterozoic age (Cadomian) basement was actively involved in their magma generation. The Grenvillian and Archaean zircons can be accounted for by that source component but they do not imply the presence of an older pre-Neoproterozoic basement rocks beneath SW Iberia

Light with tunable non-Markovian phase imprint

We introduce a simple and flexible method to generate spatially non-Markovian light with tunable coherence properties in one and two dimensions. The unusual behavior of this light is demonstrated experimentally by probing the far field and recording its diffraction pattern after a double slit: In both cases we observe instead of a central intensity maximum a line or cross shaped dark region, whose width and profile depend on the non-Markovian coherence properties. Since these properties can be controlled and easily reproduced in experiment, the presented approach lends itself to serve as a testbed to gain a deeper understanding of non-Markovian processes

Mechanical properties of PLA specimens obtained by additive manufacturing process reinforced with flax fibers

Abstract Although polylactic acid (PLA) is one of the most used materials in additive manufacturing, its mechanical properties are quite limiting for its practical application, therefore, to improve these properties it is frequent to add fibers and, in this way, create a more resistant composite material. In this paper, the authors developed PLA composites reinforced with flax fibers to evaluate the improvement of tensile and flexural strength. The experimental design of experiments was based on the L18 Taguchi array where the control factors were the extruder temperature (three levels), number of strands (three levels), infill percentage of the specimens (three levels), and whether the flax fiber had surface chemical treatment. The tensile and flexural specimens were made on a 3D printing machine and was a mold was developed to fix and align the fiber strands during the printing process. The tensile and flexural experimental tests were performed in agreement with ASTM D638.14 and ISO 14125 standards, respectively. Analyzing the results, it was verified that the surface chemical treatment (NaOH) of the fiber did not show any influence in the mechanical properties of the composites; in contrast, the infill density demonstrated a huge influence for the improvement of mechanical strength. The maximum values of tensile and bending stress were 50 MPa and 73 MPa, respectively. The natural fiber reinforcement can improve the mechanical properties of the PLA composites.info:eu-repo/semantics/publishedVersio

Patulin penicillia from a bottled water factory

Background The objective of this work is to assess the significance of penicillia isolated from a bottled water factory particularly in relation to mycotoxin production. The annual revenue from sales of bottled water is very large: bottled water has an image of being healthy. There has been an increase in reports of fungal contamination of bottled water and one of mycotoxin production. Patulin is known to be produced by Penicillium expansum and has been reported from P. brevicompactum. The isoepoxydon dehydrogenase (IDH) gene of the patulin metabolic pathway has been used to determine the potential for patulin production in fungi. Methods Fungi were obtained in pure culture from throughout a bottled water factory including from the bottled water and obtained in pure culture to assess where contamination may occur. P. expansum and P. brevicompactum strains were analysed for patulin by TLC and the IDH gene by the PCR. Other mycotoxins were also analysed. Results Penicillia were isolated from sites within the factory including P. expansum. In addition, P. brevicompactum was frequent. Patulin was detected from P. expansum and ambiguously from P. brevicompactum. However, the IDH gene was detected from both in some cases. Other important mycotoxins were detected from the strains. Secondary metabolites in medium used to produce biomass for DNA analysis were observed. Conclusions Fungi are capable of being present in bottled water from the manufacturing process. Important mycotoxin producers are present including patulin ones. The effect of mycotoxins on DNA analysis requires consideration. Further work is needed to determine whether the mycotoxins can be present in bottled water

Monitoring Vegetation Dynamics and Carbon Stock Density in Miombo Woodlands

Background The United Nation’s Program for Reducing Emissions from Deforestation and Forest Degradation (REDD+) aims to reduce the 20% contribution to global emissions of greenhouse gases from the forest sector, offering a financial value of the carbon stored in forests as an incentive for local communities. The pre-requisite for the setup of a participatory REDD + Program is the monitoring, reporting and verification (MRV) of baseline carbon stocks and their changes over time. In this study, we investigated miombo woodland’s dynamics in terms of composition, structure and biomass over a 4-year period (2005–2009), and the Carbon Stock Density (CSD) for the year 2009. The study was conducted in the Niassa National Reserve (NNR) in northern Mozambique, which is the 14th largest protected area in the world. Results Mean tree density distributed across 79 species increased slightly between 2005 and 2009, respectively, from 548 to 587 trees ha-1. Julbernardia globiflora (Benth.) was the most important species in this area [importance value index (IVI2005= 61 and IVI2009 = 54)]. The woodlands presented an inverted J-shaped diametric curve, with 69% of the individuals representing the young cohort. Woody biomass had a net increase of 3 Mg ha-1 with the highest growth observed in Dyplorhynchus condilocarpon (Müll.Arg.) Pichon (0.54 Mg ha-1). J. globiflora had a net decrease in biomass of 0.09 Mg ha-1. Total CSD density was estimated at ca. 67 MgC ha-1 ± 24.85 with soils (average 34.72 ± 17.93 MgC ha-1) and woody vegetation (average 29.8 MgC ha-1 ± 13.07) representing the major carbon pools. The results point to a relatively stable ecosystem, but they call for the need to refocus management activities. Conclusions The miombo woodlands in NNR are representative of the woodlands in the eco-region in terms of vegetation structure and composition. They experienced net increase in woody biomass, a considerable recruitment level and low mortality. According to our results, NNR may present good potential for carbon sequestration especially in soils and woody biomass, representing an important potential carbon sink. However, further investigations are needed in order to address the contribution of this area to MRV REDD + initiatives

Analysis of intact prophages in genomes of Paenibacillus larvae: An important pathogen for bees

Paenibacillus larvae is the etiological agent of American Foulbrood (AFB), a highly contagious and worldwide spread bacterial disease that affects honeybee brood. In this study, all complete P. larvae genomes available on the NCBI database were analyzed in order to detect presence of prophages using the PHASTER software. A total of 55 intact prophages were identified in 11 P. larvae genomes (5.0 +/- 2.3 per genome) and were further investigated for the presence of genes encoding relevant traits related to P. larvae. A closer look at the prophage genomes revealed the presence of several putative genes such as metabolic and antimicrobial resistance genes, toxins or bacteriocins, potentially influencing host performance. Some of the coding DNA sequences (CDS) were present in all ERIC-genotypes, while others were only found in a specific genotype. While CDS encoding toxins and antitoxins such as HicB and MazE were found in prophages of all bacterial genotypes, others, from the same category, were provided by prophages particularly to ERIC I (enhancin-like toxin), ERIC II (antitoxin SocA) and ERIC V strains (subunit of Panton-Valentine leukocidin system (PVL) LukF-PV). This is the first in-depth analysis of P. larvae prophages. It provides better knowledge on their impact in the evolution of virulence and fitness of P. larvae, by discovering new features assigned by the viruses