61 research outputs found

    Unravelling metabolic mechanisms behind chloroplast desiccation tolerance: chlorophyllous fern spore as a new promising unicellular model

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    Se sustituye el preprint por el postprint el 23-11-2020Fern spores are unicellular structures produced by the sporophyte generation that give rise to the haploid gametophyte. When released from the sporangium, spores are desiccation tolerant (DT) in the royal fern (Osmunda regalis) and contain fully developed chloroplasts. As a consequence this type of spores are called chlorophyllous spores (CS). Upon transfer to germination conditions, CS initiate a process of imbibition that suppress DT in 72h, before the germination starts. In parallel to such change in DT, thylakoids undergo a profound remodelling in composition and function. Firstly, sustained quenching of chlorophyll fluorescence is relaxed, giving rise to photochemically active CS, while lipid composition shifts from that of a resting structure to a metabolically active cell. Basically trigalactolipids decreased in favour of monogalactolipids, with a parallel desaturation of fatty acids. Storage lipids such as triacylglycerol were quickly depleted. These results highlight the importance of the structure of thylakoids lipid as a key to protect membrane integrity during desiccation, together with the saturation of fatty acids and the constitutive chlorophyll quenching to prevent oxidative damage. The CS used here, in which the same cell shifts from DT to sensitive strategy in 72h, reveal its their potential as unicellular models for future studies on DT.This work was funded by (i) the Basque Government (research project UPV/EHU IT-1018-16; and Predoctoral Fellowship to MLP); (ii) the Spanish Ministry of Economy and Competitiveness (MINECO) and the ERDF (FEDER) (research project CTM2014-53902-C2-2-P, and Juan de la Cierva-Incorporation fellowship IJCI-2014-22489 to BFM)

    Vertebrate fauna at the Allosaurus fossil-site of Andrés (Upper Jurassic), Pombal, Portugal

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    An overview of the faunistic diversity of the Andres fossil-site from the Portuguese Upper Jurassic is presented. This work provides a preliminary approach on the vertebrate fauna known at present. Although this quarry is known since the 1990’s, due to the description on the first robust evidence of a member of the neotetanuran genus Allosaurus outside North America, the results presented here are mainly derived from the analysis of the elements found during the second and third field seasons in 2005. At the moment, among the material collected from Andrés it was identified remains that represent a diverse vertebrate fauna, including fishes, sphenodonts, crocodrylomorphs, pterosaurs, and at least, seven distinct dinosaur forms. The recovery of this diverse and abundant osteological collection from one unique fossil-site is noteworthy for the Upper Jurassic Portuguese record, and only comparable with those from the Guimarota coalmine. Due to these two features plus the good preservation of the fossils, the Andres quarry may be a site of reference for the analysis of vertebrate ecosystems from the Portuguese Upper Jurassic. Dinosaur elements are the most abundant fossils, and among them it is particulary common the presence of remains identified as Allosaurus. These new evidences allow testing the previus phylogenetical hypothesys ascribing the firsts theropod remains from Andrés to A. fragilis, a species described in synchronic levels of the North American Morrison Formation. The similarity between the Allosaurus remains collected in Andres and some specimens from the Morrison Formation seems to point the existence of a genetic flow between some continental vertebrates on both sides of the proto-north Atlantic during the Upper Jurassic. Favourable tectonic conditions for the occurrence of punctual contacts between the two continents is, at present, the best scenario for explain this situation.Se presenta un analisis de la diversidad faunistica del yacimiento de Andrés en el Jurasico Superior de la Cuenca Lusitanica. El presente trabajo pretende establecer un análisis preliminar de la fauna de vertebrados identificada en el yacimiento hasta la fecha. Aunque conocido desde la decada de 1990, debido a la descripcion de la primera evidencia robusta de un neotetanuro del genero Allosaurus fuera de Norteamerica, los resultados presentados derivan principalmente del analisis de elementos encontrados durante la segunda y tercera campanas de excavacion en 2005. Hasta el momento han sido identificados entre el material recogido en Andrés, representantes de diversos taxones de vertebrados que incluyen que incluyen peces, esfenodontos, crocodilomorfos, pterosaurios y, al menos, siete formas distintas de dinosaurios. La presencia de esta diversidad y abundancia de restos osteologicos en el mismo yacimiento representa una situacion unica en el registro del Jurasico Superior portugues, tan solo comparable a la del yacimiento clasico de la mina de carbon de Guimarota. Atendiendo a estas dos caracteristicas y a la buena preservacion de los fosiles, el yacimiento de Andres puede ser considerado como una localidad de referencia para el estudio de los ecosistemas con vertebrados del Jurasico Superior portugues. Los restos de dinosaurios son los fosiles mas abundantes y, entre ellos, son particularmente comunes los asignables a Allosaurus. Estas nuevas evidencias proporcionan a A. fragilis, una especie descrita en niveles sincronicos de la Formacion Morrison en Norteamerica. La similitud entre los restos de Allosaurus recogidos en Andres y algunos de los ejemplares de la Formacion Morrison, sugiere la existencia de un flujo genético entre algunos vertebrados continentales de ambos lados del proto-Atlántico norte durante el Jurásico Superior. La existencia de condiciones tectonicas favorables para la existencia de contactos puntuales entre los dos continentes es actualmente el mejor escenario para explicar esta situacion

    Two Trebouxia algae with different physiological performances are ever-present in lichen thalli of Ramalina farinacea. Coexistence versus Competition

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    Ramalina farinacea is an epiphytic fruticose lichen that is relatively abundant in areas with Mediterranean, subtropical or temperate climates. Little is known about photobiont diversity in different lichen populations. The present study examines the phycobiont composition of several geographically distant populations of R. farinacea from the Iberian Peninsula, Canary Islands and California as well as the physiological performance of isolated phycobionts. Based on anatomical observations and molecular analyses, the coexistence of two different taxa of Trebouxia (working names, TR1 and TR9) was determined within each thallus of R. farinacea in all of the analysed populations. Examination of the effects of temperature and light on growth and photosynthesis indicated a superior performance of TR9 under relatively high temperatures and irradiances while TR1 thrived at moderate temperature and irradiance. Ramalina farinacea thalli apparently represent a specific and selective form of symbiotic association involving the same two Trebouxia phycobionts. Strict preservation of this pattern of algal coexistence is likely favoured by the different and probably complementary ecophysiological responses of each phycobiont, thus facilitating the proliferation of this lichen in a wide range of habitats and geographic areas. © 2010 Society for Applied Microbiology and Blackwell Publishing Ltd.This study was funded by the Spanish Ministry of Education and Science (CGL2006-12917-C02-01/02), the Spanish Ministry of Science and Innovation (CGL2009-13429-C02-01/02), the AECID (PCI_A/024755/09) and the Generalitat Valenciana (PROMETEO 174/2008 GVA). We are grateful to Dr J. Gimeno-Romeu (University of California, Davis, USA) and to Dr P. J. G. de Nova (IREC, Ciudad Real, Spain), who were the first to isolate DNA from Ramalina farinacea thalli in our group. Wendy Ran revised the manuscript in English.Casano, L.; Del Campo, E.; García Breijo, FJ.; Reig Armiñana, J.; Gasulla, F.; Del Hoyo, A.; Guéra, A.... (2011). Two Trebouxia algae with different physiological performances are ever-present in lichen thalli of Ramalina farinacea. Coexistence versus Competition. Environmental Microbiology. 13(3):806-818. https://doi.org/10.1111/j.1462-2920.2010.02386.xS806818133Angert, A. L., Huxman, T. E., Chesson, P., & Venable, D. L. (2009). Functional tradeoffs determine species coexistence via the storage effect. Proceedings of the National Academy of Sciences, 106(28), 11641-11645. doi:10.1073/pnas.0904512106Baker, N. R., & Oxborough, K. (s. f.). Chlorophyll Fluorescence as a Probe of Photosynthetic Productivity. Advances in Photosynthesis and Respiration, 65-82. doi:10.1007/978-1-4020-3218-9_3Barreno , E. Herrera-Campos , M. García-Breijo , F. Gasulla , F. Reig-Armiñana , J. 2008 Non photosynthetic bacteria associated to cortical structures on Ramalina and Usnea thalli from Mexico http://192.104.39.110/archive/IAL6abstracts.pdfBECK, A., FRIEDL, T., & RAMBOLD, G. (1998). Selectivity of photobiont choice in a defined lichen community: inferences from cultural and molecular studies. New Phytologist, 139(4), 709-720. doi:10.1046/j.1469-8137.1998.00231.xBilger, W., & Bj�rkman, O. (1991). Temperature dependence of violaxanthin de-epoxidation and non-photochemical fluorescence quenching in intact leaves ofGossypium hirsutum L. andMalva parviflora L. Planta, 184(2), 226-234. doi:10.1007/bf01102422Bj�rkman, O., & Demmig, B. (1987). Photon yield of O2 evolution and chlorophyll fluorescence characteristics at 77 K among vascular plants of diverse origins. Planta, 170(4), 489-504. doi:10.1007/bf00402983Bold, H. C., & Parker, B. C. (1962). Some supplementary attributes in the classification of chlorococcum species. Archiv f�r Mikrobiologie, 42(3), 267-288. doi:10.1007/bf00422045Cenis, J. L. (1992). Rapid extraction of fungal DNA for PCR amplification. Nucleic Acids Research, 20(9), 2380-2380. doi:10.1093/nar/20.9.2380Del Campo, E. M., Casano, L. M., Gasulla, F., & Barreno, E. (2010). Suitability of chloroplast LSU rDNA and its diverse group I introns for species recognition and phylogenetic analyses of lichen-forming Trebouxia algae. Molecular Phylogenetics and Evolution, 54(2), 437-444. doi:10.1016/j.ympev.2009.10.024Demmig-Adams, B., & Adams, W. W. (1996). The role of xanthophyll cycle carotenoids in the protection of photosynthesis. Trends in Plant Science, 1(1), 21-26. doi:10.1016/s1360-1385(96)80019-7Demmig-Adams, B., M�guas, C., Adams, W. W., Meyer, A., Kilian, E., & Lange, O. L. (1990). Effect of high light on the efficiency of photochemical energy conversion in a variety of lichen species with green and blue-green phycobionts. Planta, 180(3), 400-409. doi:10.1007/bf01160396DePriest, P. T. (2004). Early Molecular Investigations of Lichen-Forming Symbionts: 1986–2001. Annual Review of Microbiology, 58(1), 273-301. doi:10.1146/annurev.micro.58.030603.123730DOERING, M., & PIERCEY-NORMORE, M. D. (2009). Genetically divergent algae shape an epiphytic lichen community on Jack Pine in Manitoba. The Lichenologist, 41(1), 69-80. doi:10.1017/s0024282909008111Friedl, T. (1989). Comparative ultrastructure of pyrenoids inTrebouxia (Microthamniales, Chlorophyta). Plant Systematics and Evolution, 164(1-4), 145-159. doi:10.1007/bf00940435Gasulla, F., de Nova, P. G., Esteban-Carrasco, A., Zapata, J. M., Barreno, E., & Guéra, A. (2009). Dehydration rate and time of desiccation affect recovery of the lichenic algae Trebouxia erici: alternative and classical protective mechanisms. Planta, 231(1), 195-208. doi:10.1007/s00425-009-1019-yGasulla, F., Guéra, A., & Barreno, E. (2010). “A simple and rapid method for isolating lichen photobionts“. Symbiosis, 51(2), 175-179. doi:10.1007/s13199-010-0064-4Gauze, G. F. (1934). The struggle for existence, by G. F. Gause. doi:10.5962/bhl.title.4489Genty, B., Briantais, J.-M., & Baker, N. R. (1989). The relationship between the quantum yield of photosynthetic electron transport and quenching of chlorophyll fluorescence. Biochimica et Biophysica Acta (BBA) - General Subjects, 990(1), 87-92. doi:10.1016/s0304-4165(89)80016-9Gross, K. (2008). Positive interactions among competitors can produce species-rich communities. Ecology Letters, 11(9), 929-936. doi:10.1111/j.1461-0248.2008.01204.xGUZOW-KRZEMIŃSKA, B. (2006). Photobiont flexibility in the lichen Protoparmeliopsis muralis as revealed by ITS rDNA analyses. The Lichenologist, 38(5), 469-476. doi:10.1017/s0024282906005068Haruta, S., Kato, S., Yamamoto, K., & Igarashi, Y. (2009). Intertwined interspecies relationships: approaches to untangle the microbial network. Environmental Microbiology, 11(12), 2963-2969. doi:10.1111/j.1462-2920.2009.01956.xJOHANSEN, S., & HAUGEN, P. (2001). A new nomenclature of group I introns in ribosomal DNA. RNA, 7(7), 935-936. doi:10.1017/s1355838201010500Jones, A. ., Berkelmans, R., van Oppen, M. J. ., Mieog, J. ., & Sinclair, W. (2008). A community change in the algal endosymbionts of a scleractinian coral following a natural bleaching event: field evidence of acclimatization. Proceedings of the Royal Society B: Biological Sciences, 275(1641), 1359-1365. doi:10.1098/rspb.2008.0069Kopecky, J., Azarkovich, M., Pfündel, E. E., Shuvalov, V. A., & Heber, U. (2005). Thermal Dissipation of Light Energy is Regulated Differently and by Different Mechanisms in Lichens and Higher Plants. Plant Biology, 7(2), 156-167. doi:10.1055/s-2005-837471Kosugi, M., Arita, M., Shizuma, R., Moriyama, Y., Kashino, Y., Koike, H., & Satoh, K. (2009). Responses to Desiccation Stress in Lichens are Different from Those in Their Photobionts. Plant and Cell Physiology, 50(4), 879-888. doi:10.1093/pcp/pcp043Kranner, I., Cram, W. J., Zorn, M., Wornik, S., Yoshimura, I., Stabentheiner, E., & Pfeifhofer, H. W. (2005). Antioxidants and photoprotection in a lichen as compared with its isolated symbiotic partners. Proceedings of the National Academy of Sciences, 102(8), 3141-3146. doi:10.1073/pnas.0407716102Kroken, S., & Taylor, J. W. (2000). Phylogenetic Species, Reproductive Mode, and Specificity of the Green AlgaTrebouxiaForming Lichens with the Fungal GenusLetharia. The Bryologist, 103(4), 645-660. doi:10.1639/0007-2745(2000)103[0645:psrmas]2.0.co;2Little, A. F. (2004). Flexibility in Algal Endosymbioses Shapes Growth in Reef Corals. Science, 304(5676), 1492-1494. doi:10.1126/science.1095733Loarie, S. R., Duffy, P. B., Hamilton, H., Asner, G. P., Field, C. B., & Ackerly, D. D. (2009). The velocity of climate change. Nature, 462(7276), 1052-1055. doi:10.1038/nature08649Muggia, L., Grube, M., & Tretiach, M. (2008). Genetic diversity and photobiont associations in selected taxa of the Tephromela atra group (Lecanorales, lichenised Ascomycota). Mycological Progress, 7(3), 147-160. doi:10.1007/s11557-008-0560-6Niyogi, K. K. (2004). Is PsbS the site of non-photochemical quenching in photosynthesis? Journal of Experimental Botany, 56(411), 375-382. doi:10.1093/jxb/eri056O’Brien, H. E., Miadlikowska, J., & Lutzoni, F. (2005). Assessing host specialization in symbiotic cyanobacteria associated with four closely related species of the lichen fungusPeltigera. European Journal of Phycology, 40(4), 363-378. doi:10.1080/09670260500342647Ohmura, Y., Kawachi, M., Kasai, F., Watanabe, M. M., & Takeshita, S. (2006). Genetic combinations of symbionts in a vegetatively reproducing lichen,Parmotrema tinctorum, based on ITS rDNA sequences. The Bryologist, 109(1), 43-59. doi:10.1639/0007-2745(2006)109[0043:gcosia]2.0.co;2Piercey-Normore, M. D. (2005). The lichen-forming ascomyceteEvernia mesomorphaassociates with multiple genotypes ofTrebouxia jamesii. New Phytologist, 169(2), 331-344. doi:10.1111/j.1469-8137.2005.01576.xPombert, J.-F., Lemieux, C., & Turmel, M. (2006). BMC Biology, 4(1), 3. doi:10.1186/1741-7007-4-3Rambold, G., Friedl, T., & Beck, A. (1998). Photobionts in Lichens: Possible Indicators of Phylogenetic Relationships? The Bryologist, 101(3), 392. doi:10.1639/0007-2745(1998)101[392:pilpio]2.0.co;2Romeike, J., Friedl, T., Helms, G., & Ott, S. (2002). Genetic Diversity of Algal and Fungal Partners in Four Species of Umbilicaria (Lichenized Ascomycetes) Along a Transect of the Antarctic Peninsula. Molecular Biology and Evolution, 19(8), 1209-1217. doi:10.1093/oxfordjournals.molbev.a004181Rosenberg, E., Sharon, G., & Zilber-Rosenberg, I. (2009). The hologenome theory of evolution contains Lamarckian aspects within a Darwinian framework. Environmental Microbiology, 11(12), 2959-2962. doi:10.1111/j.1462-2920.2009.01995.xSchreiber, U., Schliwa, U., & Bilger, W. (1986). Continuous recording of photochemical and non-photochemical chlorophyll fluorescence quenching with a new type of modulation fluorometer. Photosynthesis Research, 10(1-2), 51-62. doi:10.1007/bf00024185Skaloud, P., & Peksa, O. (2010). Evolutionary inferences based on ITS rDNA and actin sequences reveal extensive diversity of the common lichen alga Asterochloris (Trebouxiophyceae, Chlorophyta). Molecular Phylogenetics and Evolution, 54(1), 36-46. doi:10.1016/j.ympev.2009.09.035Wegley, L., Edwards, R., Rodriguez-Brito, B., Liu, H., & Rohwer, F. (2007). Metagenomic analysis of the microbial community associated with the coral Porites astreoides. Environmental Microbiology, 9(11), 2707-2719. doi:10.1111/j.1462-2920.2007.01383.xWeis, E., & Berry, J. A. (1987). Quantum efficiency of Photosystem II in relation to ‘energy’-dependent quenching of chlorophyll fluorescence. Biochimica et Biophysica Acta (BBA) - Bioenergetics, 894(2), 198-208. doi:10.1016/0005-2728(87)90190-3Wornik, S., & Grube, M. (2009). Joint Dispersal Does Not Imply Maintenance of Partnerships in Lichen Symbioses. Microbial Ecology, 59(1), 150-157. doi:10.1007/s00248-009-9584-yYAHR, R., VILGALYS, R., & DEPRIEST, P. T. (2004). Strong fungal specificity and selectivity for algal symbionts in Florida scrub Cladonia lichens. Molecular Ecology, 13(11), 3367-3378. doi:10.1111/j.1365-294x.2004.02350.xYahr, R., Vilgalys, R., & DePriest, P. T. (2006). Geographic variation in algal partners of Cladonia subtenuis (Cladoniaceae) highlights the dynamic nature of a lichen symbiosis. New Phytologist, 171(4), 847-860. doi:10.1111/j.1469-8137.2006.01792.xZoller, S. (2003). Slow algae, fast fungi: exceptionally high nucleotide substitution rate differences between lichenized fungi Omphalina and their symbiotic green algae Coccomyxa. Molecular Phylogenetics and Evolution, 29(3), 629-640. doi:10.1016/s1055-7903(03)00215-

    Spatial Division Multiplexed Microwave Signal processing by selective grating inscription in homogeneous multicore fibers

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    [EN] The use of Spatial Division Multiplexing for Microwave Photonics signal processing is proposed and experimentally demonstrated, for the first time to our knowledge, based on the selective inscription of Bragg gratings in homogeneous multicore fibers. The fabricated devices behave as sampled true time delay elements for radiofrequency signals offering a wide range of operation possibilities within the same optical fiber. The key to processing flexibility comes from the implementation of novel multicavity configurations by inscribing a variety of different fiber Bragg gratings along the different cores of a 7-core fiber. This entails the development of the first fabrication method to inscribe high-quality gratings characterized by arbitrary frequency spectra and located in arbitrary longitudinal positions along the individual cores of a multicore fiber. Our work opens the way towards the development of unique compact fiber-based solutions that enable the implementation of a wide variety of 2D (spatial and wavelength diversity) signal processing functionalities that will be key in future fiber-wireless communications scenarios. We envisage that Microwave Photonics systems and networks will benefit from this technology in terms of compactness, operation versatility and performance stability.We thank Prof. Jose Capmany for the thoughtful discussions and recommendations that greatly contribute to this work. This research was supported by the Spanish MINECO Projects TEC2014-60378-C2-1-R and TEC2015-62520-ERC, the Valencian Research Excellency Award Program GVA PROMETEO 2013/012, the Spanish MECD FPU Scholarship (FPU13/04675) for J. Hervas, and the Spanish MINECO Ramon y Cajal Program (RYC-2014-16247) for I. Gasulla.Gasulla Mestre, I.; Barrera Vilar, D.; Hervás-Peralta, J.; Sales Maicas, S. (2017). Spatial Division Multiplexed Microwave Signal processing by selective grating inscription in homogeneous multicore fibers. Scientific Reports. 7(41727):1-10. https://doi.org/10.1038/srep41727S110741727Samsung Electronics Co, “5G Vision”, available at http://www.samsung.com/global/business-images/insights/2015/Samsung-5G-Vision-0.pdf (2015).Technology Focus on Microwave Photonics. Nat. Photonics 5, 723 (2011).J. Capmany, J. Mora, I. Gasulla, J. Sancho, J. Lloret & S. Sales . Microwave photonic signal processing. IEEE J. Lightw. Technol. 31, 571–586 (2013).Y. Long & J. Wang . Ultra-high peak rejection notch microwave photonic filter using a single silicon microring resonator. Opt. Express 23, 17739–17750 (2015).Y. Long & J. Wang . All-optical tuning of a nonlinear silicon microring assisted microwave photonic filter: theory and experiment. Opt. Express 23, 17758–17771 (2015).Y. Long, L. Zhou & J. Wang . Photonic-assisted microwave signal multiplication and modulation using a silicon Mach–Zehnder modulator. Sci. Reports 6, 20215 (2016).J. Sancho, J. Bourderionnet, J. Lloret, S. Combrié, I. Gasulla, S. Xavier, S. Sales, P. Colman, G. Lehoucq, D. Dolfi, J. Capmany & A. De Rossi . Integrable microwave filter based on a photonic crystal delay line. Nat. Commun. 3, 1075 (2012).F. Ohman, K. Yvind & J. Mørk . Slow Light in a Semiconductor Waveguide for True-Time Delay Applications in Microwave Photonics. IEEE Photon. Technol. Lett. 19, 1145–1157 (2007).P. A. Morton & J. B. Khurgin. Microwave photonic delay line with separate tuning of the optical carrier. IEEE Photon. Technol. Lett. 21, 1686–1688 (2009).D. Marpaung, C. Roeloffzen, R. Heideman, A. Leinse, S. Sales & J. Capmany . Integrated microwave photonics. Lasers Photon. Rev. 7, 506–538 (2013).I. Gasulla & J. Capmany . Microwave photonics applications of multicore fibers. Photonics J. 4, 877–888 (2012).S. Garcia & I. Gasulla . Design of Heterogeneous Multicore fibers as sampled True Time Delay Lines. Opt. Lett. 40, 621–624 (2015).F. Zeng & J. Yao . All-optical microwave filters using uniform fiber Bragg gratings with identical reflectivities. IEEE J. Lightw. Technol. 23, 1410 (2005).C. Wang & J. Yao . Fiber Bragg gratings for microwave photonics subsystems. Opt. Express 21, 22868–22884 (2013).I. Gasulla, D. Barrera & S. Sales . Microwave photonic devices based on multicore fibers. 16th International Conference on Transparent Optical Networks (ICTON), Graz, Austria, 2014.I. Gasulla, D. Barrera, J. Hervás, S. García & S. Sales . Multi-cavity Microwave Photonics devices built upon multicore fibres. 18th International Conference on Transparent Optical Networks (ICTON), Trento (Italy), pp. 1–4, 2016.K. O. Hill & G. Meltz . Fiber Bragg grating technology fundamentals and overview. IEEE J. Lightw. Technol. 15, 1263–1276 (1997).T. Erdogan . Fiber grating spectra. IEEE J. Lightw. Technol. 15, 1277–1294 (1997).D. Barrera, I. Gasulla & S. Sales . Multipoint two-dimensional curvature optical fiber sensor based on a non-twisted homogeneous four-core fiber. IEEE J. Lightw. Technol. 33, 2445–2450 (2015).T. Birks, B. Mangan, A. Diez, J. Cruz, S. Leon-Saval, J. Bland-Hawthorn & D. Murphy . Multicore optical fibres for astrophotonics. In CLEO/Europe and EQEC 2011 Conference Digest, OSA Technical Digest (CD)d (Optical Society of America, 2011), paper JSIII2_1.C. Wang, Z. Yan, Q. Sun, Z. Sun, C. Mou, J. Zhang, A. Badmos & L. Zhang . Fibre Bragg gratings fabrication in four core fibres. Proc. SPIE 9886, Micro-Structured and Specialty Optical Fibres IV, 98860H (2016).M. J. Cole, W. H. Loh, R. I. Laming, M. N. Zervas & S. Barcelos . Moving fibre/phase mask-scanning beam technique for enhanced flexibility in producing fibre gratings with uniform phase mask. Electron. Lett. 31, 1488–1490 (1995).M. Gallagher & U. Österberg . Time resolved 3.10 eV luminescence in germanium-doped silica glass. Appl. Phys. Lett. 63, 2987–2988 (1993).T. Komukai & M. Nakazawa . Fabrication of high-quality long fiber Bragg grating by monitoring 3.1 eV radiation (400 nm) from GeO defects. IEEE Photon. Tech. Lett. 8, 1495–1497 (1996).R. R. Thomson, H. T. Bookey, N. D. Psaila, A. Fender, S. Campbell, W. N. MacPherson, J. S. Barton, D. T. Reid & A. K. Kar . Ultrafast-laser inscription of a three dimensional fan-out device for multicore fiber coupling applications. Opt. Express 15, 11691–11697 (2007)

    A predictive model and risk factors for case fatality of covid-19

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    This study aimed to create an individualized analysis model of the risk of intensive care unit (ICU) admission or death for coronavirus disease 2019 (COVID-19) patients as a tool for the rapid clinical management of hospitalized patients in order to achieve a resilience of medical resources. This is an observational, analytical, retrospective cohort study with longitudinal follow-up. Data were collected from the medical records of 3489 patients diagnosed with COVID-19 using RT-qPCR in the period of highest community transmission recorded in Europe to date: February–June 2020. The study was carried out in in two health areas of hospital care in the Madrid region: the central area of the Madrid capital (Hospitales de Madrid del Grupo HM Hospitales (CH-HM), n = 1931) and the metropolitan area of Madrid (Hospital Universitario Príncipe de Asturias (MH-HUPA) n = 1558). By using a regression model, we observed how the different patient variables had unequal importance. Among all the analyzed variables, basal oxygen saturation was found to have the highest relative importance with a value of 20.3%, followed by age (17.7%), lymphocyte/leukocyte ratio (14.4%), CRP value (12.5%), comorbidities (12.5%), and leukocyte count (8.9%). Three levels of risk of ICU/death were established: low-risk level (20%). At the high-risk level, 13% needed ICU admission, 29% died, and 37% had an ICU–death outcome. This predictive model allowed us to individualize the risk for worse outcome for hospitalized patients affected by COVID-19

    A Predictive Model and Risk Factors for Case Fatality of COVID-19

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    This study aimed to create an individualized analysis model of the risk of intensive care unit (ICU) admission or death for coronavirus disease 2019 (COVID-19) patients as a tool for the rapid clinical management of hospitalized patients in order to achieve a resilience of medical resources. This is an observational, analytical, retrospective cohort study with longitudinal follow-up. Data were collected from the medical records of 3489 patients diagnosed with COVID-19 using RT-qPCR in the period of highest community transmission recorded in Europe to date: February-June 2020. The study was carried out in in two health areas of hospital care in the Madrid region: the central area of the Madrid capital (Hospitales de Madrid del Grupo HM Hospitales (CH-HM), n = 1931) and the metropolitan area of Madrid (Hospital Universitario Príncipe de Asturias (MH-HUPA) n = 1558). By using a regression model, we observed how the different patient variables had unequal importance. Among all the analyzed variables, basal oxygen saturation was found to have the highest relative importance with a value of 20.3%, followed by age (17.7%), lymphocyte/leukocyte ratio (14.4%), CRP value (12.5%), comorbidities (12.5%), and leukocyte count (8.9%). Three levels of risk of ICU/death were established: low-risk level (20%). At the high-risk level, 13% needed ICU admission, 29% died, and 37% had an ICU-death outcome. This predictive model allowed us to individualize the risk for worse outcome for hospitalized patients affected by COVID-19

    Lichen rehydration in heavy metal polluted environments: Pb modulates the oxidative response of both Ramalina farinacea thalli and its isolated microalgae

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    Lichens are adapted to desiccation/rehydration and accumulate heavy metals, which induce ROS especially from the photobiont photosynthetic pigments. Although their mechanisms of abiotic stress tolerance are still to be unravelled, they seem related to symbionts' reciprocal upregulation of antioxidant systems. With the aim to study the effect of Pb on oxidative status during rehydration, the kinetics of intracellular ROS, lipid peroxidation and chlorophyll autofluorescence of whole Ramalina farinacea thalli and its isolated microalgae (Trebouxia TR1 and T. TR9) was recorded. A genetic characterization of the microalgae present in the thalli used was also carried out in order to assess possible correlations among the relative abundance of each phycobiont, their individual physiological responses and that of the entire thallus. Unexpectedly, Pb decreased ROS and lipid peroxidation in thalli and its phycobionts, associated with a lower chlorophyll autofluorescence. Each phycobiont showed a particular pattern, but the oxidative response of the thallus paralleled the TR1's, agreeing with the genetic identification of this strain as the predominant phycobiont. We conclude that: (1) the lichen oxidative behaviour seems to be modulated by the predominant phycobiont and (2) Pb evokes in R. farinacea and its phycobionts strong mechanisms to neutralize its own oxidant effects along with those of rehydration
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