Análisis de la vegetación del área de protección de flora y fauna Cañón de Santa Elena (desierto chihuahuense, México) utilizando Modelos Digitales de Elevación

Las áreas naturales protegidas, se han convertido en una oportunidad para preservar nuestros recursos naturales y sirven como laboratorio para estudiar sus diferentes componentes. En el área de protección de flora y fauna Cañón de Santa Elena, situada en la frontera de México y Estados Unidos, dentro del desierto chihuahuense, se realizó una investigación de su composición botánica a lo largo del gradiente altitudinal, desde los 600 a los 2.400 msnm. Se usaron técnicas multivariantes para agrupar los diferentes tipos de vegetación y posteriormente se generaron mapas utilizando Modelos Digitales de Elevación. Se obtuvieron siete grupos de vegetación y se identificaron las especies dominantes y subdominantes en cada grupo, así como su distribución geográfica y superficie que ocupan dentro del área protegida representativa del ecosistema estudiado

Ecophysiological and molecular involvement of extracellular-regulated protein kinases (ERK 1/2) in the response of Dunaliella viridis to heat stress

The eukaryotic green microalga Dunaliella viridis has shown an outstanding capacity to face a broad range of environmental stressors such as, high irradiance, UV radiation, salinity, and temperature, among others. The lack of a rigid cell wall, as well as, its unique ability to respond, adapt and grow under stressful conditions makes Dunaliella an excellent model to study stress signal transduction in eukaryotic unicellular organisms. Mitogen-activated protein kinases (MAPKs) are highly conserved serine/threonine kinases that convert extracellular stimuli into a wide variety of responses at both cellular and nuclear levels. In eukaryotic cells, MAPKs are involved in both environmental stress responses (JNK and p38 pathways) and cell proliferation and differentiation (ERK pathway) through protein kinase cascades. Previously, two different ERK proteins, ERK1 and ERK2 (ERK1/2) have been identified in D. viridis. Based on the non-direct implication of the ERK-like proteins in the acclimatization process against environmental stress proven by the specific blockade of the cascades, different short-term heat-shock (SH) experiments have been conducted in this work to uncover molecular mechanisms underlying the role of ERK1/2 in heat stress. The evolution of the maximum quantum yield of D. viridis after non-lethal SH, together with protein immunedetection by ERK1/2 western blotting and qRT-PCR experiments revealed that the ERK1/2 proteins are not directly involved in the response to heat stress, and that they are rapidly deactivated after stress, leading to a transient inhibition of cell division. Behaviour of MAPK-like proteins in algae is largely unknown at present. The analysis of their mechanism of action, as well as their function in this model microalga, will allow us to decipher the fate of unicellular eukaryotic organisms in aquatic ecosystems subjected to environmental stress derived from the conditions prevailing within a framework of global climate change.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

Optimization of lipase production by solid-state fermentation of olive pomace: from flask to laboratory-scale packed-bed bioreactor

Lipases are versatile catalysts with many applications and can be produced by solid-state fermentation (SSF) using agro-industrial wastes. The aim of this work was to maximize the production of Aspergillus ibericus lipase under SSF of olive pomace (OP) and wheat bran (WB), evaluating the effect on lipase production of C/N ratio, lipids, phenols, content of sugars of substrates and nitrogen source addition. Moreover, the implementation of the SSF process in a packed-bed bioreactor and the improvement of lipase extraction conditions were assessed. Low C/N ratios and high content of lipids led to maximum lipase production. Optimum SSF conditions were achieved with a C/N mass ratio of 25.2 and 10.2% (w/w) lipids in substrate, by the mixture of OP:WB (1:1) and supplemented with 1.33% (w/w) (NH4)2SO4. Studies in a packed-bed bioreactor showed that the lower aeration rates tested prevented substrate dehydration, improving lipase production. In this work, the important role of Triton X-100 on lipase extraction from the fermented solid substrate has been shown. A final lipase activity of 223 ± 5 U g1 (dry basis) was obtained after 7 days of fermentation.Felisbela Oliveira acknowledges the financial support from Fundação para a Ciência e Tecnologia (FCT) of Portugal through grant SFRH/BD/87953/2012. José Manuel Salgado was supported by grant CEB/N2020–INV/01/2016 from Project ‘‘BIOTECNORTE-Underpinning Biotechnology to foster the north of Portugal bioeconomy’’ (NORTE-01-0145-FEDER-000004). Luı ´s Abrunhosa was supported by grant UMINHO/BPD/51/2015 from project UID/BIO/04469/2013 financed by FCT/MEC (OE). This study was supported by the Portuguese Foundation for Science and Technology (FCT) under the scope of the strategic funding of UID/BIO/04469/2013 unit and COMPETE 2020 (POCI-01-0145-FEDER006684) and BioTecNorte operation (NORTE-01-0145-FEDER000004) funded by the European Regional Development Fund under the scope of Norte2020–Programa Operacional Regional do Norte. Noelia Pérez-Rodríguez acknowledges the financial support of FPU fellowship from the Spanish Ministry of Education, Culture and Sports. The authors thank the Spanish Ministry of Economy and Competitiveness for the financial support of this work (Project CTQ2015-71436-C2-1-R), which has partial financial support from the FEDER funds of the European Union.info:eu-repo/semantics/publishedVersio

Combined fit to the spectrum and composition data measured by the Pierre Auger Observatory including magnetic horizon effects

The measurements by the Pierre Auger Observatory of the energy spectrum and mass composition of cosmic rays can be interpreted assuming the presence of two extragalactic source populations, one dominating the flux at energies above a few EeV and the other below. To fit the data ignoring magnetic field effects, the high-energy population needs to accelerate a mixture of nuclei with very hard spectra, at odds with the approximate E$^{-2}$ shape expected from diffusive shock acceleration. The presence of turbulent extragalactic magnetic fields in the region between the closest sources and the Earth can significantly modify the observed CR spectrum with respect to that emitted by the sources, reducing the flux of low-rigidity particles that reach the Earth. We here take into account this magnetic horizon effect in the combined fit of the spectrum and shower depth distributions, exploring the possibility that a spectrum for the high-energy population sources with a shape closer to E$^{-2}$ be able to explain the observations

Extraction of the Muon Signals Recorded with the Surface Detector of the Pierre Auger Observatory Using Recurrent Neural Networks

We present a method based on the use of Recurrent Neural Networks to extract the muon component from the time traces registered with water-Cherenkov detector (WCD) stations of the Surface Detector of the Pierre Auger Observatory. The design of the WCDs does not allow to separate the contribution of muons to the time traces obtained from the WCDs from those of photons, electrons and positrons for all events. Separating the muon and electromagnetic components is crucial for the determination of the nature of the primary cosmic rays and properties of the hadronic interactions at ultra-high energies. We trained a neural network to extract the muon and the electromagnetic components from the WCD traces using a large set of simulated air showers, with around 450 000 simulated events. For training and evaluating the performance of the neural network, simulated events with energies between 1018.5, eV and 1020 eV and zenith angles below 60 degrees were used. We also study the performance of this method on experimental data of the Pierre Auger Observatory and show that our predicted muon lateral distributions agree with the parameterizations obtained by the AGASA collaboration