Propiedades de transmisión de electrones de Dirac a través de superredes Cantor en grafenoTransmission properties of Dirac electrons through Cantor monolayer graphene superlattices

In this work we use the transfer matrix method to studythe tunneling of Dirac electrons through aperiodic monolayer graphene superlattices. We consider a graphene sheet deposited on top of slabs of Silicon-Oxide (SiO2) and Silicon-Carbide (SiC) substrates, in which we applied the Cantor’s series. We calculatethe transmittance for different fundamental parameters such as: starting width, incident energy, incident angle and generation number of the Cantor’s series. In this case, the transmittance as function of energy presents self-similar features as a function of the generation number. We also compute the angular distribution of the transmittance for fixed energies finding a self-similar patterns between generations. Finally, we calculate the scaling factor for some transmittance spectra, which effectively show scalability.En este trabajo usamos el método de la matriz de transferencia para estudiar el tunelamiento de los electrones de Dirac a través de superredes aperiodicas en grafeno. Consideramosuna hoja de grafeno depositada encima de bloques de sustratos de Óxido de Silicio (SiO2) y Carburo de Silicio (SiC), en los cuales aplicamos la serie de Cantor. Calculamos la transmitancia para diferentes parámetros fundamentales tales como: ancho de partida, energía de incidencia, ángulo de incidencia y número de generación de la serie de Cantor. En este caso, la transmitancia como función de la energía presenta rasgos autosimilares al variar el número de generación. También computamos la distribución angular de la transmitancia para energías fijas econtrando un patrón autosimilar entre generaciones. Por último, calculamos los factores de escala para algunos espectros de la transmitancia, los cuales efectivamente muestran escalabilida

Propiedades de transmisión de electrones de Dirac a través de superredes Cantor en grafeno

En este trabajo usamos el método de la matriz de transferencia para estudiar el tunelamiento de los electrones de Dirac a través de superredes aperiodicas en grafeno. Consideramos una hoja de grafeno depositada encima de bloques de sustratos de Óxido de Silicio (SiO2) y Carburo de Silicio (SiC), en los cuales aplicamos la serie de Cantor. Calculamos la transmitancia para diferentes parámetros fundamentales tales como: ancho de partida, energía de incidencia, ángulo de incidencia y número de generación de la serie de Cantor. En este caso, la transmitancia como función de la energía presenta rasgos autosimilares al variar el número de generación. También computamos la distribución angular de la transmitancia para energías fijas econtrando un patrón autosimilar entre generaciones. Por último, calculamos los factores de escala para algunos espectros de la transmitancia, los cuales efectivamente muestran escalabilidad.In this work we use the transfer matrix method to study the tunneling of Dirac electrons through aperiodic monolayer graphene superlattices. We consider a graphene sheet deposited on top of slabs of Silicon-Oxide (SiO2) and Silicon-Carbide (SiC) substrates, in which we applied the Cantor's series. We calculate the transmittance for different fundamental parameters such as: starting width, incident energy, incident angle and generation number of the Cantor's series. In this case, the transmittance as function of energy presents self-similar features as a function of the generation number. We also compute the angular distribution of the transmittance for fixed energies finding a self-similar patterns between generations. Finally, we calculate the scaling factor for some transmittance spectra, which effectively show scalability

Effects of Sex, Strain, and Energy Intake on Hallmarks of Aging in Mice.

Calorie restriction (CR) is the most robust non-genetic intervention to delay aging. However, there are a number of emerging experimental variables that alter CR responses. We investigated the role of sex, strain, and level of CR on health and survival in mice. CR did not always correlate with lifespan extension, although it consistently improved health across strains and sexes. Transcriptional and metabolomics changes driven by CR in liver indicated anaplerotic filling of the Krebs cycle together with fatty acid fueling of mitochondria. CR prevented age-associated decline in the liver proteostasis network while increasing mitochondrial number, preserving mitochondrial ultrastructure and function with age. Abrogation of mitochondrial function negated life-prolonging effects of CR in yeast and worms. Our data illustrate the complexity of CR in the context of aging, with a clear separation of outcomes related to health and survival, highlighting complexities of translation of CR into human interventions.pre-print5,92 M

Evaluating tree-to-tree competition during stand development in a relict Scots pine forest: how much does climate matter?

Key message: Competitive interactions change over time and their influence on tree growth is intensified during drought events in marginal Scots pine populations. Abstract: Competition is a key factor driving forest dynamics and stand structure during the course of stand development. Although the role neighbourhood competition on stand dynamics has received increasing attention, the response of competition to environmental fluctuations and stand development remains poorly explored. We evaluated changes in competition during stand development in a dry-edge Scots pine relict population located in Central Spain. Typically, tree-to-tree interactions have been investigated through static competition measurements, which usually lack the temporal variation associated to natural forest development and environmental conditions. Here, we assessed how individual and neighbourhood components of competition evolved along a 35-year period, and we related competition dynamics to population structure and drought levels. On six plots, 508 trees were mapped and diameters at breast height (DBH) were measured. Two increment cores were taken from target trees to derive basal area increment (BAI), and neighbourhood was reconstructed back to 1980. Results provide insights into inter-annual variability in competition effects and their role on tree radial growth depending on climatic conditions. From the year 2005 onwards, both individual and neighbourhood components of competition showed a decoupled pattern over time. This effect was particularly pronounced during the extreme drought in 2012, in which the individual component decreased, whereas the neighbourhood component increased. In addition, climatic variability modulated the competition effects during stand development. This approach of evaluating competition dynamics proves to be promising for studying forest stand development and the influence of climate impacts on tree populations subjected to xeric conditions

Evolution of Class IITCPgenes in perianth bearing Piperales and their contribution to the bilateral calyx in Aristolochia

[EN] Controlled spatiotemporal cell division and expansion are responsible for floral bilateral symmetry. Genetic studies have pointed to class II TCP genes as major regulators of cell division and floral patterning in model core eudicots. Here we study their evolution in perianth-bearing Piperales and their expression in Aristolochia, a rare occurrence of bilateral perianth outside eudicots and monocots. The evolution of class II TCP genes reveals single-copy CYCLOIDEA-like genes and three paralogs of CINCINNATA (CIN) in early diverging angiosperms. All class II TCP genes have independently duplicated in Aristolochia subgenus Siphisia. Also CIN2 genes duplicated before the diversification of Saruma and Asarum. Sequence analysis shows that CIN1 and CIN3 share motifs with Cyclin proteins and CIN2 genes have lost the miRNA319a binding site. Expression analyses of all paralogs of class II TCP genes in Aristolochia fimbriata point to a role of CYC and CIN genes in maintaining differential perianth expansion during mid- and late flower developmental stages by promoting cell division in the distal and ventral portion of the limb. It is likely that class II TCP genes also contribute to cell division in the leaf, the gynoecium and the ovules in A. fimbriata.We thank Anny Garces Palacio, Sarita Munoz, Pablo Perez-Mesa (Universidad de Antioquia, Colombia), Cecilia Zumajo-Cardona (The New York Botanical Garden), Ana Berbel and Clara Ines Ortiz-Ramirez (Instituto de Biologia Molecular y Celular de Plantas, CSIC-UVP, Valencia, Spain) for photographs and assistance during laboratory work. We also thank Sebastian Gonzalez (Massachusetts College of Art and Design) for taking some of the photographs in Figs 1 and 2. Thanks are also due to the Dresden Junior Fellowship for allowing the visiting professor fellowship of NPM to the Technishe Universitat Dresden during 2019. This research was funded by Estrategia de Sostenibilidad 2018-2019 the Convocatoria Programaticas 2017-2018 (code 2017-16302), and the 2018-2019 Fondo de Internacionalizacion (code 201926230) from the Universidad de Antioquia, the iCOOP + 2016 grant COOPB20250 from Centro Superior de Investigacion Cientifica, CSIC and the ExpoSEED (H2020.MSCA-RISE2015-691109) EU grant.Pabon-Mora, N.; Madrigal, Y.; Alzate, JF.; Ambrose, BA.; Ferrandiz Maestre, C.; Wanke, S.; Neinhuis, C.... (2020). Evolution of Class IITCPgenes in perianth bearing Piperales and their contribution to the bilateral calyx in Aristolochia. New Phytologist. 228(2):752-769. https://doi.org/10.1111/nph.167197527692282Aguilar-Martínez, J. A., Poza-Carrión, C., & Cubas, P. (2007). Arabidopsis BRANCHED1Acts as an Integrator of Branching Signals within Axillary Buds. The Plant Cell, 19(2), 458-472. doi:10.1105/tpc.106.048934Almeida, J., Rocheta, M., & Galego, L. (1997). Genetic control of flower shape in Antirrhinum majus. Development, 124(7), 1387-1392. doi:10.1242/dev.124.7.1387Altschul, S. F., Gish, W., Miller, W., Myers, E. W., & Lipman, D. J. (1990). Basic local alignment search tool. Journal of Molecular Biology, 215(3), 403-410. doi:10.1016/s0022-2836(05)80360-2Ambrose, B. A., Lerner, D. R., Ciceri, P., Padilla, C. M., Yanofsky, M. F., & Schmidt, R. J. (2000). Molecular and Genetic Analyses of the Silky1 Gene Reveal Conservation in Floral Organ Specification between Eudicots and Monocots. Molecular Cell, 5(3), 569-579. doi:10.1016/s1097-2765(00)80450-5Ballester, P., Navarrete-Gómez, M., Carbonero, P., Oñate-Sánchez, L., & Ferrándiz, C. (2015). Leaf expansion in Arabidopsis is controlled by a TCP-NGA regulatory module likely conserved in distantly related species. Physiologia Plantarum, 155(1), 21-32. doi:10.1111/ppl.12327Bartlett, M. E., & Specht, C. D. (2011). Changes in expression pattern of the teosinte branched1- like genes in the Zingiberales provide a mechanism for evolutionary shifts in symmetry across the order. American Journal of Botany, 98(2), 227-243. doi:10.3732/ajb.1000246Bliss, B. J., Wanke, S., Barakat, A., Ayyampalayam, S., Wickett, N., Wall, P. K., … dePamphilis, C. W. (2013). Characterization of the basal angiosperm Aristolochia fimbriata: a potential experimental system for genetic studies. BMC Plant Biology, 13(1), 13. doi:10.1186/1471-2229-13-13Busch, A., & Zachgo, S. (2007). Control of corolla monosymmetry in the Brassicaceae Iberis amara. Proceedings of the National Academy of Sciences, 104(42), 16714-16719. doi:10.1073/pnas.0705338104Citerne, H. L., Reyes, E., Le Guilloux, M., Delannoy, E., Simonnet, F., Sauquet, H., … Damerval, C. (2016). Characterization ofCYCLOIDEA-like genes in Proteaceae, a basal eudicot family with multiple shifts in floral symmetry. Annals of Botany, 119(3), 367-378. doi:10.1093/aob/mcw219Corley, S. B., Carpenter, R., Copsey, L., & Coen, E. (2005). Floral asymmetry involves an interplay between TCP and MYB transcription factors in Antirrhinum. Proceedings of the National Academy of Sciences, 102(14), 5068-5073. doi:10.1073/pnas.0501340102Crawford, B. C. W., Nath, U., Carpenter, R., & Coen, E. S. (2004). CINCINNATA Controls Both Cell Differentiation and Growth in Petal Lobes and Leaves of Antirrhinum. Plant Physiology, 135(1), 244-253. doi:10.1104/pp.103.036368Cubas, P. (2002). Role of TCP genes in the evolution of morphological characters in angiosperms. Developmental Genetics and Plant Evolution, 247-266. doi:10.1201/9781420024982.ch13Cubas, P., Lauter, N., Doebley, J., & Coen, E. (1999). The TCP domain: a motif found in proteins regulating plant growth and development. The Plant Journal, 18(2), 215-222. doi:10.1046/j.1365-313x.1999.00444.xDamerval, C., Citerne, H., Conde e Silva, N., Deveaux, Y., Delannoy, E., Joets, J., … Nadot, S. (2019). Unraveling the Developmental and Genetic Mechanisms Underpinning Floral Architecture in Proteaceae. Frontiers in Plant Science, 10. doi:10.3389/fpls.2019.00018Damerval, C., Citerne, H., Le Guilloux, M., Domenichini, S., Dutheil, J., Ronse de Craene, L., & Nadot, S. (2013). Asymmetric morphogenetic cues along the transverse plane: Shift from disymmetry to zygomorphy in the flower of Fumarioideae. American Journal of Botany, 100(2), 391-402. doi:10.3732/ajb.1200376Damerval, C., Guilloux, M. L., Jager, M., & Charon, C. (2006). Diversity and Evolution ofCYCLOIDEA-Like TCP Genes in Relation to Flower Development in Papaveraceae. Plant Physiology, 143(2), 759-772. doi:10.1104/pp.106.090324Danisman, S., van der Wal, F., Dhondt, S., Waites, R., de Folter, S., Bimbo, A., … Immink, R. G. H. (2012). Arabidopsis Class I and Class II TCP Transcription Factors Regulate Jasmonic Acid Metabolism and Leaf Development Antagonistically. Plant Physiology, 159(4), 1511-1523. doi:10.1104/pp.112.200303Danisman, S., van Dijk, A. D. J., Bimbo, A., van der Wal, F., Hennig, L., de Folter, S., … Immink, R. G. H. (2013). Analysis of functional redundancies within the Arabidopsis TCP transcription factor family. Journal of Experimental Botany, 64(18), 5673-5685. doi:10.1093/jxb/ert337Doebley, J. (2004). The Genetics of Maize Evolution. Annual Review of Genetics, 38(1), 37-59. doi:10.1146/annurev.genet.38.072902.092425Doebley, J., Stec, A., & Gustus, C. (1995). teosinte branched1 and the origin of maize: evidence for epistasis and the evolution of dominance. Genetics, 141(1), 333-346. doi:10.1093/genetics/141.1.333Doebley, J., Stec, A., & Hubbard, L. (1997). The evolution of apical dominance in maize. Nature, 386(6624), 485-488. doi:10.1038/386485a0Efroni, I., Blum, E., Goldshmidt, A., & Eshed, Y. (2008). A Protracted and Dynamic Maturation Schedule UnderliesArabidopsisLeaf Development. The Plant Cell, 20(9), 2293-2306. doi:10.1105/tpc.107.057521Elomaa, P., Zhao, Y., & Zhang, T. (2018). Flower heads in Asteraceae—recruitment of conserved developmental regulators to control the flower-like inflorescence architecture. Horticulture Research, 5(1). doi:10.1038/s41438-018-0056-8Endress, P. K. (2012). The Immense Diversity of Floral Monosymmetry and Asymmetry Across Angiosperms. The Botanical Review, 78(4), 345-397. doi:10.1007/s12229-012-9106-3Ferrándiz, C., Liljegren, S. J., & Yanofsky, M. F. (2000). Negative Regulation of the SHATTERPROOF Genes by FRUITFULL During Arabidopsis Fruit Development. Science, 289(5478), 436-438. doi:10.1126/science.289.5478.436Galego, L. (2002). Role of DIVARICATA in the control of dorsoventral asymmetry in Antirrhinum flowers. Genes & Development, 16(7), 880-891. doi:10.1101/gad.221002Gaudin, V., Lunness, P. A., Fobert, P. R., Towers, M., Riou-Khamlichi, C., Murray, J. A. H., … Doonan, J. H. (2000). The Expression of D-Cyclin Genes Defines Distinct Developmental Zones in Snapdragon Apical Meristems and Is Locally Regulated by the Cycloidea Gene. Plant Physiology, 122(4), 1137-1148. doi:10.1104/pp.122.4.1137González, F., & Pabón‐Mora, N. (2015). Trickery flowers: the extraordinary chemical mimicry of Aristolochia to accomplish deception to its pollinators. New Phytologist, 206(1), 10-13. doi:10.1111/nph.13328González, F., & Stevenson, D. W. (2000). Perianth development and systematics of Aristolochia. Flora, 195(4), 370-391. doi:10.1016/s0367-2530(17)30995-7Heery, D. M., Kalkhoven, E., Hoare, S., & Parker, M. G. (1997). A signature motif in transcriptional co-activators mediates binding to nuclear receptors. Nature, 387(6634), 733-736. doi:10.1038/42750Hileman, L. C. (2014). Trends in flower symmetry evolution revealed through phylogenetic and developmental genetic advances. Philosophical Transactions of the Royal Society B: Biological Sciences, 369(1648), 20130348. doi:10.1098/rstb.2013.0348Hoang, D. T., Chernomor, O., von Haeseler, A., Minh, B. Q., & Vinh, L. S. (2017). UFBoot2: Improving the Ultrafast Bootstrap Approximation. Molecular Biology and Evolution, 35(2), 518-522. doi:10.1093/molbev/msx281Horn, S., Pabón-Mora, N., Theuß, V. S., Busch, A., & Zachgo, S. (2015). Analysis of the CYC/TB1 class of TCP transcription factors in basal angiosperms and magnoliids. The Plant Journal, 81(4), 559-571. doi:10.1111/tpj.12750Howarth, D. G., & Donoghue, M. J. (2006). Phylogenetic analysis of the «ECE» (CYC/TB1) clade reveals duplications predating the core eudicots. Proceedings of the National Academy of Sciences, 103(24), 9101-9106. doi:10.1073/pnas.0602827103Howarth, D. G., Martins, T., Chimney, E., & Donoghue, M. J. (2011). Diversification of CYCLOIDEA expression in the evolution of bilateral flower symmetry in Caprifoliaceae and Lonicera (Dipsacales). Annals of Botany, 107(9), 1521-1532. doi:10.1093/aob/mcr049Kalyaanamoorthy, S., Minh, B. Q., Wong, T. K. F., von Haeseler, A., & Jermiin, L. S. (2017). ModelFinder: fast model selection for accurate phylogenetic estimates. Nature Methods, 14(6), 587-589. doi:10.1038/nmeth.4285Katoh, K. (2002). MAFFT: a novel method for rapid multiple sequence alignment based on fast Fourier transform. Nucleic Acids Research, 30(14), 3059-3066. doi:10.1093/nar/gkf436Kosugi, S., & Ohashi, Y. (2002). DNA binding and dimerization specificity and potential targets for the TCP protein family. The Plant Journal, 30(3), 337-348. doi:10.1046/j.1365-313x.2002.01294.xKoyama, T., Furutani, M., Tasaka, M., & Ohme-Takagi, M. (2006). TCP Transcription Factors Control the Morphology of Shoot Lateral Organs via Negative Regulation of the Expression of Boundary-Specific Genes inArabidopsis. The Plant Cell, 19(2), 473-484. doi:10.1105/tpc.106.044792Leppik, E. E. (1972). Origin and Evolution of Bilateral Symmetry in Flowers. Evolutionary Biology, 49-85. doi:10.1007/978-1-4757-0256-9_3Li, C., Potuschak, T., Colon-Carmona, A., Gutierrez, R. A., & Doerner, P. (2005). Arabidopsis TCP20 links regulation of growth and cell division control pathways. Proceedings of the National Academy of Sciences, 102(36), 12978-12983. doi:10.1073/pnas.0504039102Li, M., Zhang, D., Gao, Q., Luo, Y., Zhang, H., Ma, B., … Xue, Y. (2019). Genome structure and evolution of Antirrhinum majus L. Nature Plants, 5(2), 174-183. doi:10.1038/s41477-018-0349-9Li, S. (2015). The Arabidopsis thaliana TCP transcription factors: A broadening horizon beyond development. Plant Signaling & Behavior, 10(7), e1044192. doi:10.1080/15592324.2015.1044192Li, S., Gutsche, N., & Zachgo, S. (2011). The ROXY1 C-Terminal L**LL Motif Is Essential for the Interaction with TGA Transcription Factors    . Plant Physiology, 157(4), 2056-2068. doi:10.1104/pp.111.185199Lin, Y.-F., Chen, Y.-Y., Hsiao, Y.-Y., Shen, C.-Y., Hsu, J.-L., Yeh, C.-M., … Tsai, W.-C. (2016). Genome-wide identification and characterization ofTCPgenes involved in ovule development ofPhalaenopsis equestris. Journal of Experimental Botany, 67(17), 5051-5066. doi:10.1093/jxb/erw273Da Luo, Carpenter, R., Copsey, L., Vincent, C., Clark, J., & Coen, E. (1999). Control of Organ Asymmetry in Flowers of Antirrhinum. Cell, 99(4), 367-376. doi:10.1016/s0092-8674(00)81523-8Luo, D., Carpenter, R., Vincent, C., Copsey, L., & Coen, E. (1996). Origin of floral asymmetry in Antirrhinum. Nature, 383(6603), 794-799. doi:10.1038/383794a0Madrigal, Y., Alzate, J. F., & Pabón-Mora, N. (2017). Evolution and Expression Patterns of TCP Genes in Asparagales. Frontiers in Plant Science, 8. doi:10.3389/fpls.2017.00009Martín-Trillo, M., & Cubas, P. (2010). TCP genes: a family snapshot ten years later. Trends in Plant Science, 15(1), 31-39. doi:10.1016/j.tplants.2009.11.003MillerMA PfeifferW SchwartzT.2010.Creating the CIPRES Science Gateway for inference of large phylogenetic trees. [WWW document] URLhttp://www.phylo.org[accessed 5 June 2020].Mondragón-Palomino, M., & Trontin, C. (2011). High time for a roll call: gene duplication and phylogenetic relationships of TCP-like genes in monocots. Annals of Botany, 107(9), 1533-1544. doi:10.1093/aob/mcr059Nath, U., Crawford, B. C. W., Carpenter, R., & Coen, E. (2003). Genetic Control of Surface Curvature. Science, 299(5611), 1404-1407. doi:10.1126/science.1079354Navaud, O., Dabos, P., Carnus, E., Tremousaygue, D., & Hervé, C. (2007). TCP Transcription Factors Predate the Emergence of Land Plants. Journal of Molecular Evolution, 65(1), 23-33. doi:10.1007/s00239-006-0174-zNguyen, L.-T., Schmidt, H. A., von Haeseler, A., & Minh, B. Q. (2014). IQ-TREE: A Fast and Effective Stochastic Algorithm for Estimating Maximum-Likelihood Phylogenies. Molecular Biology and Evolution, 32(1), 268-274. doi:10.1093/molbev/msu300Pabón-Mora, N., Suárez-Baron, H., Ambrose, B. A., & González, F. (2015). Flower Development and Perianth Identity Candidate Genes in the Basal Angiosperm Aristolochia fimbriata (Piperales: Aristolochiaceae). Frontiers in Plant Science, 6. doi:10.3389/fpls.2015.01095Palatnik, J. F., Allen, E., Wu, X., Schommer, C., Schwab, R., Carrington, J. C., & Weigel, D. (2003). Control of leaf morphogenesis by microRNAs. Nature, 425(6955), 257-263. doi:10.1038/nature01958Parapunova, V., Busscher, M., Busscher-Lange, J., Lammers, M., Karlova, R., Bovy, A. G., … de Maagd, R. A. (2014). Identification, cloning and characterization of the tomato TCP transcription factor family. BMC Plant Biology, 14(1). doi:10.1186/1471-2229-14-157Peréz-Mesa, P., Ortíz-Ramírez, C. I., González, F., Ferrándiz, C., & Pabón-Mora, N. (2020). Expression of gynoecium patterning transcription factors in Aristolochia fimbriata (Aristolochiaceae) and their contribution to gynostemium development. EvoDevo, 11(1). doi:10.1186/s13227-020-00149-8Preston, J. C., & Hileman, L. C. (2012). Parallel evolution of TCP and B-class genes in Commelinaceae flower bilateral symmetry. EvoDevo, 3(1), 6. doi:10.1186/2041-9139-3-6Preston, J. C., Kost, M. A., & Hileman, L. C. (2009). Conservation and diversification of the symmetry developmental program among close relatives of snapdragon with divergent floral morphologies. New Phytologist, 182(3), 751-762. doi:10.1111/j.1469-8137.2009.02794.xRambautA.2014.FigTree: tree figure drawing tool. [WWW document] URLhttp://tree.bio.ed.ac.uk/software/figtree/.Rudall, P. J., & Bateman, R. M. (2004). Evolution of zygomorphy in monocot flowers: iterative patterns and developmental constraints. New Phytologist, 162(1), 25-44. doi:10.1111/j.1469-8137.2004.01032.xSargent, R. D. (2004). Floral symmetry affects speciation rates in angiosperms. Proceedings of the Royal Society of London. Series B: Biological Sciences, 271(1539), 603-608. doi:10.1098/rspb.2003.2644Suárez-Baron, H., Alzate, J. F., González, F., Ambrose, B. A., & Pabón-Mora, N. (2019). Genetic mechanisms underlying perianth epidermal elaboration of Aristolochia ringens Vahl (Aristolochiaceae). Flora, 253, 56-66. doi:10.1016/j.flora.2019.03.004Suárez-Baron, H., Pérez-Mesa, P., Ambrose, B. A., González, F., & Pabón-Mora, N. (2016). Deep into the Aristolochia Flower: Expression of C, D, and E-Class Genes inAristolochia fimbriata(Aristolochiaceae). Journal of Experimental Zoology Part B: Molecular and Developmental Evolution, 328(1-2), 55-71. doi:10.1002/jez.b.22686Viola, I. L., Uberti Manassero, N. G., Ripoll, R., & Gonzalez, D. H. (2011). The Arabidopsis class I TCP transcription factor AtTCP11 is a developmental regulator with distinct DNA-binding properties due to the presence of a threonine residue at position 15 of the TCP domain. Biochemical Journal, 435(1), 143-155. doi:10.1042/bj20101019Wang, J., Wang, Y., & Luo, D. (2010). LjCYC Genes Constitute Floral Dorsoventral Asymmetry in Lotus japonicus. Journal of Integrative Plant Biology, 52(11), 959-970. doi:10.1111/j.1744-7909.2010.00926.xYuan, Z., Gao, S., Xue, D.-W., Luo, D., Li, L.-T., Ding, S.-Y., … Zhang, D.-B. (2008). RETARDED PALEA1 Controls Palea Development and Floral Zygomorphy in Rice  . Plant Physiology, 149(1), 235-244. doi:10.1104/pp.108.128231Zhang, W., Kramer, E. M., & Davis, C. C. (2010). Floral symmetry genes and the origin and maintenance of zygomorphy in a plant-pollinator mutualism. Proceedings of the National Academy of Sciences, 107(14), 6388-6393. doi:10.1073/pnas.0910155107Zhang, W., Steinmann, V. W., Nikolov, L., Kramer, E. M., & Davis, C. C. (2013). Divergent genetic mechanisms underlie reversals to radial floral symmetry from diverse zygomorphic flowered ancestors. Frontiers in Plant Science, 4. doi:10.3389/fpls.2013.0030

Clasificación automática de las vocales en el lenguaje de señas colombiano

Sign language recognition is a highly-complex problem due to the amount of static and dynamic gestures needed to represent such language, especially when it changes from country to country. This article focuses on static recognition of vowels in Colombian Sign Language. A total of 151 images were acquired for each class, and an additional non-vowel class with different scenes was also considered. The object of interest was cut out of the rest of the scene in the captured image by using color information. Subsequently, features were extracted to describe the gesture that corresponds to a vowel or to the class that does not match any vowel. Next, four sets of features were selected. The first one contained all of them; from it, three new sets were generated. The second one was extracted from a subset of features given by the Principal Component Analysis (PCA) algorithm. The third set was obtained by Sequential Feature Selection (SFS) with the FISHER measure. The last set was completed with SFS based on the performance of the K-Nearest Neighbor (KNN) algorithm. Finally, multiple classifiers were tested on each set by cross-validation. Most of the classifiers achieved a performance over 90%, which led to conclude that the proposed method allows an appropriate class distinction.El reconocimiento del lenguaje de señas es un problema de alta complejidad, debido a la cantidad de gestos estáticos y dinámicos necesarios para representar dicho lenguaje, teniendo en cuenta que el mismo variará para cada país en particular. Este artículo se enfoca en el reconocimiento de las vocales del lenguaje colombiano de señas, de forma estática. Se adquirieron 151 imágenes por cada clase, teniendo en cuenta también una clase no vocal adicional con diferentes escenas. A partir de cada imagen capturada se separa el objeto de interés del resto de la escena usando información de color; luego, se extraen características para describir el gesto correspondiente a cada vocal o a la clase que no corresponde a ninguna vocal. Posteriormente, se seleccionan cuatro conjuntos de características. El primero con la totalidad de ellas; a partir de este salen tres nuevos conjuntos: el segundo extrayendo un subconjunto de características mediante el algoritmo de Análisis de Componentes Principales (PCA). El tercer conjunto, aplicando Selección Secuencial hacia Adelante (SFS), mediante la medida de FISHER y el último conjunto con SFS basado en el desempeño del clasificador de los vecinos más cercanos (KNN). Finalmente se prueban múltiples clasificadores para cada conjunto por medio de validación cruzada, obteniendo un desempeño superior al 90% para la mayoría de los clasificadores, concluyendo que la metodología propuesta permite una adecuada separación de las clases

Modeling of autosomal-dominant retinitis pigmentosa in Caenorhabditis elegans uncovers a nexus between global impaired functioning of certain splicing factors and cell type-specific apoptosis

Retinitis pigmentosa (RP) is a rare genetic disease that causes gradual blindness through retinal degeneration. Intriguingly, seven of the 24 genes identified as responsible for the autosomal-dominant form (adRP) are ubiquitous spliceosome components whose impairment causes disease only in the retina. The fact that these proteins are essential in all organisms hampers genetic, genomic, and physiological studies, but we addressed these difficulties by using RNAi in Caenorhabditis elegans. Our study of worm phenotypes produced by RNAi of splicing-related adRP (s-adRP) genes functionally distinguishes between components of U4 and U5 snRNP complexes, because knockdown of U5 proteins produces a stronger phenotype. RNA-seq analyses of worms where s-adRP genes were partially inactivated by RNAi, revealed mild intron retention in developing animals but not in adults, suggesting a positive correlation between intron retention and transcriptional activity. interestingly, RNAi of s-adRP genes produces an increase in the expression of atl-1 (homolog of human ATR), which is normally activated in response to replicative stress and certain DNA-damaging agents. The up-regulation of atl-1 correlates with the ectopic expression of the pro-apoptotic gene egl-1 and apoptosis in hypodermal cells, which produce the cuticle, but not in other cell types. Our model in C. elegans resembles s-adRP in two aspects: The phenotype caused by global knockdown of s-adRP genes is cell type-specific and associated with high transcriptional activity. Finally, along with a reduced production of mature transcripts, we propose a model in which the retina-specific cell death in s-adRP patients can be induced through genomic instability

What drives growth of Scots pine in continental Mediterranean climates: drought, low temperatures or both?

Scots pine forests subjected to continental Mediterranean climates undergo cold winter temperatures and drought stress. Recent climatic trends towards warmer and drier conditions across the Mediterranean Basin might render some of these pine populations more vulnerable to drought-induced growth decline at the Southernmost limit of the species distribution. We investigated how cold winters and dry growing seasons drive the radial growth of Scots pine subject to continental Mediterranean climates by relating growth to climate variables at local (elevational gradient) and regional (latitudinal gradient) scales. Local climate-growth relationships were quantified on different time scales (5-, 10- and 15-days) to evaluate the relative role of elevation and specific site characteristics. A negative water balance driven by high maximum temperatures in June (low-elevation sites) and July (high-elevation sites) was the major constraint on growth, particularly on a 5- to 10-day time scale. Warm nocturnal conditions in January were associated with wider rings at the high-elevation sites. At the regional scale, Scots pine growth mainly responded positively to July precipitation, with a stronger association at lower elevations and higher latitudes. January minimum temperatures showed similar patterns but played a secondary role as a driver of tree growth. The balance between positive and negative effects of summer precipitation and winter temperature on radial growth depends on elevation and latitude, with low-elevation populations being more prone to suffer drought and heat stress; whereas, high-elevation populations may be favoured by warmer winter conditions. This negative impact of summer heat and drought has increased during the past decades. This interaction between climate and site conditions and local adaptations is therefore decisive for the future performance and persistence of Scots pine populations in continental Mediterranean climates. Forecasting changes in the Scots pine range due to climate change should include this site-related information to obtain more realistic predictions, particularly in Mediterranean rear-edge areas