Distributions of charged massive scalars and fermions from evaporating higher-dimensional black holes

A detailed numerical analysis is performed to obtain the Hawking spectrum for charged, massive brane scalars and fermions on the approximate background of a brane charged rotating higher-dimensional black hole constructed in arXiv:0907.5107. We formulate the problem in terms of a "spinor-like" first order system of differential wave equations not only for fermions, but for scalars as well and integrate it numerically. Flux spectra are presented for non-zero mass, charge and rotation, confirming and extending previous results based on analytic approximations. In particular we describe an inverted charge splitting at low energies, which is not present in four or five dimensions and increases with the number of extra dimensions. This provides another signature of the evaporation of higher-dimensional black holes in TeV scale gravity scenarios.Comment: 19 pages, 6 figures, minor typos corrected, 1 page added with a discussion on higher spins, added reference

Economic History and History of Economics: Complementary Approaches to Portuguese Economic Development

This chapter focuses on how the problems of economic development were addressed by the Portuguese historiography of the late nineteenth and twentieth centuries. The ensuing discussion benefits from the simultaneous consideration of two historiographical domains that complement each other: economic history and the history of economics. On the one hand, there are the authors and texts of economic history that seek to describe the facts and circumstances related to the functioning and dynamics of economic reality, for a given period or succession of periods, in order to establish evolutionary trends. On the other hand, there are the authors and texts of the history of economics that seek to adopt analytical forms (principles and laws) and doctrinal and programmatic frameworks (visions and ideologies) aimed at providing explanatory meaning to the observed economic changes, phenomena and regularities. A true understanding of the important issues pertaining to Portuguese economic development is to be found, however, in the intersection of these distinct but complementary historiographical perspectives.info:eu-repo/semantics/publishedVersio

Fire triggers reestablishment of invasive grasses in a neotropical savanna under restoration

This is the author accepted manuscript. The final version is available from Wiley via the DOI in this recordExcluding invasive grasses is a significant challenge for neotropical savanna restoration. Invasive grasses alter fire regimes with feedbacks on soil nutrient pools, favoring their own dominance over native species. Here we combine remote sensing with an opportunistic experiment to monitor a savanna under restoration before and after a large natural fire. We measured vegetation and soil fertility in a 4-year-old restoration area in Central Brazil, which was subsequently hit by a lightning fire. The restoration area was originally utilized as pasture, dominated by invasive grasses. Over the restoration period, native fast-growing grasses replaced the invasive species. Within the first year after the fire, we found that the fire had reduced aboveground biomass, species diversity, and abundance of native species with acquisitive resource-use strategies. Soil phosphorus and pH increased after the fire and favored the re-invasion of exotic grass species. Our findings suggest that fire occurrence early in the restoration process may trigger exotic grass re-invasion driven by soil nutrient enrichment. To diminish the re-invasion risk from exotic grasses in savannas undergoing restoration, managers should beware of the early fire or manage soil fertility after fire events. Successful restoration may also benefit by incorporating native species with high post-fire recovery capacity.Natural Environment Research Council (NERC)FAPESPFundação Grupo Boticário de Proteção à NaturezaCoordenação de Aperfeiçoamento Pessoal de Nível Superior - Brasil (CAPES)Instituto SerrapilheiraCNP

Mapping native and non-native vegetation in the Brazilian Cerrado using freely available satellite products

This is the final version. Available on open access from Nature Research via the DOI in this recordNative vegetation across the Brazilian Cerrado is highly heterogeneous and biodiverse and provides important ecosystem services, including carbon and water balance regulation, however, land-use changes have been extensive. Conservation and restoration of native vegetation is essential and could be facilitated by detailed landcover maps. Here, across a large case study region in Goiás State, Brazil (1.1 Mha), we produced physiognomy level maps of native vegetation (n = 8) and other landcover types (n = 5). Seven different classification schemes using different combinations of input satellite imagery were used, with a Random Forest classifier and 2-stage approach implemented within Google Earth Engine. Overall classification accuracies ranged from 88.6-92.6% for native and non-native vegetation at the formation level (stage-1), and 70.7-77.9% for native vegetation at the physiognomy level (stage-2), across the seven different classifications schemes. The differences in classification accuracy resulting from varying the input imagery combination and quality control procedures used were small. However, a combination of seasonal Sentinel-1 (C-band synthetic aperture radar) and Sentinel-2 (surface reflectance) imagery resulted in the most accurate classification at a spatial resolution of 20 m. Classification accuracies when using Landsat-8 imagery were marginally lower, but still reasonable. Quality control procedures that account for vegetation burning when selecting vegetation reference data may also improve classification accuracy for some native vegetation types. Detailed landcover maps, produced using freely available satellite imagery and upscalable techniques, will be important tools for understanding vegetation functioning at the landscape scale and for implementing restoration projects.ShellFAPESPNatural Environment Research Council (NERC

Antibacterial activity of Thymoquinone, an active principle of Nigella sativa and its potency to prevent bacterial biofilm formation

<p>Abstract</p> <p>Background</p> <p>Thymoquinone is an active principle of <it>Nigella sativa </it>seed known as "Habbah Al-Sauda" in Arabic countries and "Sinouj" in Tunisia. Bacterial biofilms tend to exhibit significant tolerance to antimicrobials drugs during infections.</p> <p>Methods</p> <p>The antibacterial activity of Thymoquinone (TQ) and its biofilm inhibition potencies were investigated on 11 human pathogenic bacteria. The growth and development of the biofilm were assessed using the crystal violet (CV) and the 2, 3-bis [2-methyloxy-4-nitro-5-sulfophenyl]-2H-tetrazolium-5-carboxanilide (XTT) reduction assay.</p> <p>Results</p> <p>TQ exhibited a significant bactericidal activity against the majority of the tested bacteria (MICs values ranged from 8 to 32 μg/ml) especially Gram positive cocci (<it>Staphylococcus aureus </it>ATCC 25923 and <it>Staphylococcus epidermidis </it>CIP 106510). Crystal violet assay demonstrated that the minimum biofilm inhibition concentration (BIC50) was reached with 22 and 60 μg/ml for <it>Staphylococcus aureus </it>ATCC 25923 and <it>Staphylococcus epidermidis </it>CIP 106510 respectively. In addition our data revealed that cells oxidative activity was influenced by TQ supplementation. In the same way, TQ prevented cell adhesion to glass slides surface.</p> <p>Conclusion</p> <p>The ability of TQ to prevent biofilm formation warrants further investigation to explore its use as bioactive substances with antibiofilm potential.</p