Confirmación de la ausencia del alga marina asiática Codium fragile subsp. fragile (Codiaceae, Chlorophyta) en el Pacífico de México, mediante datos moleculares

Background. Codium fragile is a green alga that inhabits the Pacific coast of Baja California, Mexico, whose first records date back to 1909. This species has several subspecies, one of them Codium fragile subsp. fragile, originally from Japan, has proven to be an invasive organism in different parts of the world. Objectives. Confirm the presence or absence of this invasive strain on the coast of the Mexican Pacific, comparing with individuals from Japan, the United States and Mexico using molecular tools. Methods. We analyzed 20 individuals of the different species recorded for the Mexican Pacific and ten outside the region, including two as outgroup. The genomic DNA was extracted using the Sanger method, regions of the psb and 23S markers were amplified, the sequences obtained were edited and aligned in MEGA and MESQUITE, subsequently phylogenetic analyses of maximum likelihood were carried out in PAUP and MEGA and Bayesian inference in MrBayes. Genetic distances were obtained in MEGA and PAUP. Results. It is shown that, genetically, the individuals from Mexico integrate a clade different from the Asian entity, with inter-species genetic distances that were located at 6% for the 23S marker, while for the subclades of C. fragile the distance between them was 0.4%. For psb, the distance was 25% between species and 2.2% between these two subspecies. Conclusions. Individuals from California and Mexico nested in the native clade C. fragile, while others also from California are recognized with that of Japan as belonging to the invasive clade (C. fragile subsp. fragile). At the moment, the absence of this invasive strain in the Pacific of Mexico is confirmed.Antecedentes. Codium fragile es un alga verde que habita en las costas del Pacífico de Baja California, México, cuyos primeros registros datan de 1909. Esta especie que posee varias subespecies, una de ellas Codium fragile subsp. fragile, oriunda de Japón, ha demostrado ser un organismo invasor en diferentes partes del mundo. Objetivos. Confirmar la presencia o ausencia de esta cepa invasora en las costas del Pacífico mexicano, comparando individuos de Japón, Estados Unidos y México mediante el uso de herramientas moleculares. Métodos. Se analizaron 20 individuos de las especies registradas para el Pacífico mexicano y diez fuera de la región, incluyendo además dos como grupo externo. El DNA genómico se extrajo mediante el método Sanger, se amplificaron regiones de los marcadores psb y 23S, las secuencias obtenidas se editaron y alinearon en MEGA y MESQUITE, posteriormente se realizaron análisis filogenéticos de máxima verosimilitud en PAUP y MEGA y de inferencia bayesiana en MrBayes. Las distancias genéticas se obtuvieron en MEGA y PAUP. Resultados. Se demuestra que, genéticamente, los individuos de México integran un clado diferente a la entidad asiática, con distancias genéticas inter-especie que se ubicaron en 6% para el marcador 23S, mientras que para los subclados de C. fragile la distancia entre ellos fue de 0.4%. Para psb, la distancia fue del 25% entre especies y de 2.2% entre estas dos subespecies. Conclusiones. Individuos de California y México se anidaron en el clado nativo C. fragile, mientras que otros procedentes también de California se reconocen con el de Japón como pertenecientes al clado invasor (C. fragile subsp. fragile); así por el momento, se confirma la ausencia de esta cepa invasora en el Pacífico de México

Combining the Two-Layers PageRank Approach with the APA Centrality in Networks with Data

[EN] Identifying the influential nodes in complex networks is a fundamental and practical topic at the moment. In this paper, a new centrality measure for complex networks is proposed based on two contrasting models that have their common origin in the well-known PageRank centrality. On the one hand, the essence of the model proposed is taken from the Adapted PageRank Algorithm (APA) centrality, whose main characteristic is that constitutes a measure to establish a ranking of nodes considering the importance of some dataset associated to the network. On the other hand, a technique known as two-layers PageRank approach is applied to this model. This technique focuses on the idea that the PageRank centrality can be understood as a two-layer network, the topological and teleportation layers, respectively. The main point of the proposed centrality is that it combines the APA centrality with the idea of two-layers; however, the difference now is that the teleportation layer is replaced by a layer that collects the data present in the network. This combination gives rise to a new algorithm for ranking the nodes according to their importance. Subsequently, the coherence of the new measure is demonstrated by calculating the correlation and the quantitative differences of both centralities (APA and the new centrality). A detailed study of the differences of both centralities, taking different types of networks, is performed. A real urban network with data randomly generated is evaluated as well as the well-known Zachary's karate club network. Some numerical results are carried out by varying the values of the alpha parameter-known as dumping factor in PageRank model-that varies the importance given to the two layers (topology and data) within the computation of the new centrality. The proposed algorithm takes the best characteristics of the models on which it is based: on the one hand, it is a measure of centrality, in complex networks with data, whose calculation is stable numerically and, on the other hand, it is able to separate the topological properties of the network and the influence of the data.Partially supported by the Spanish Government, Ministerio de Economia y Competividad, grant number TIN2017-84821-P.Agryzkov, T.; Pedroche Sánchez, F.; Tortosa, L.; Vicent, JF. (2018). Combining the Two-Layers PageRank Approach with the APA Centrality in Networks with Data. ISPRS International Journal of Geo-Information. 7(12):1-22. https://doi.org/10.3390/ijgi7120480S122712Crucitti, P., Latora, V., & Porta, S. (2006). Centrality measures in spatial networks of urban streets. Physical Review E, 73(3). doi:10.1103/physreve.73.036125Bonacich, P. (1991). Simultaneous group and individual centralities. 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Quantifying the influence of scientists and their publications: distinguishing between prestige and popularity. New Journal of Physics, 14(3), 033033. doi:10.1088/1367-2630/14/3/033033Porta, S., Crucitti, P., & Latora, V. (2006). The network analysis of urban streets: A dual approach. Physica A: Statistical Mechanics and its Applications, 369(2), 853-866. doi:10.1016/j.physa.2005.12.063Jiang, B. (2009). Ranking spaces for predicting human movement in an urban environment. International Journal of Geographical Information Science, 23(7), 823-837. doi:10.1080/13658810802022822Bonacich, P. (1987). Power and Centrality: A Family of Measures. American Journal of Sociology, 92(5), 1170-1182. doi:10.1086/228631Boldi, P., & Vigna, S. (2014). Axioms for Centrality. Internet Mathematics, 10(3-4), 222-262. doi:10.1080/15427951.2013.865686Freeman, L. C. (1977). A Set of Measures of Centrality Based on Betweenness. Sociometry, 40(1), 35. doi:10.2307/3033543Brandes, U. (2001). A faster algorithm for betweenness centrality*. The Journal of Mathematical Sociology, 25(2), 163-177. doi:10.1080/0022250x.2001.9990249Haveliwala, T. H. (2003). Topic-sensitive pagerank: A context-sensitive ranking algorithm for web search. IEEE Transactions on Knowledge and Data Engineering, 15(4), 784-796. doi:10.1109/tkde.2003.1208999Berkhin, P. (2005). A Survey on PageRank Computing. Internet Mathematics, 2(1), 73-120. doi:10.1080/15427951.2005.10129098García, E., Pedroche, F., & Romance, M. (2013). On the localization of the personalized PageRank of complex networks. Linear Algebra and its Applications, 439(3), 640-652. doi:10.1016/j.laa.2012.10.051Langville, A., & Meyer, C. (2004). Deeper Inside PageRank. Internet Mathematics, 1(3), 335-380. doi:10.1080/15427951.2004.10129091Bianchini, M., Gori, M., & Scarselli, F. (2005). Inside PageRank. ACM Transactions on Internet Technology, 5(1), 92-128. doi:10.1145/1052934.1052938Migallón, H., Migallón, V., Palomino, J. A., & Penadés, J. (2018). A heuristic relaxed extrapolated algorithm for accelerating PageRank. Advances in Engineering Software, 120, 88-95. doi:10.1016/j.advengsoft.2016.01.024Agryzkov, T., Oliver, J. L., Tortosa, L., & Vicent, J. F. (2012). An algorithm for ranking the nodes of an urban network based on the concept of PageRank vector. Applied Mathematics and Computation, 219(4), 2186-2193. doi:10.1016/j.amc.2012.08.064Agryzkov, T., Tortosa, L., & Vicent, J. F. (2016). New highlights and a new centrality measure based on the Adapted PageRank Algorithm for urban networks. Applied Mathematics and Computation, 291, 14-29. doi:10.1016/j.amc.2016.06.036Agryzkov, T., Tortosa, L., Vicent, J. F., & Wilson, R. (2017). A centrality measure for urban networks based on the eigenvector centrality concept. Environment and Planning B: Urban Analytics and City Science, 46(4), 668-689. doi:10.1177/2399808317724444Conti, M., & Kumar, M. (2010). Opportunities in Opportunistic Computing. Computer, 43(1), 42-50. doi:10.1109/mc.2010.19Zhang, Y., Song, L., Jiang, C., Tran, N. H., Dawy, Z., & Han, Z. (2017). A Social-Aware Framework for Efficient Information Dissemination in Wireless Ad Hoc Networks. IEEE Communications Magazine, 55(1), 174-179. doi:10.1109/mcom.2017.1600029cmBoccaletti, S., Bianconi, G., Criado, R., del Genio, C. I., Gómez-Gardeñes, J., Romance, M., … Zanin, M. (2014). The structure and dynamics of multilayer networks. Physics Reports, 544(1), 1-122. doi:10.1016/j.physrep.2014.07.001Kivela, M., Arenas, A., Barthelemy, M., Gleeson, J. P., Moreno, Y., & Porter, M. A. (2014). Multilayer networks. Journal of Complex Networks, 2(3), 203-271. doi:10.1093/comnet/cnu016Pedroche, F., Romance, M., & Criado, R. (2016). A biplex approach to PageRank centrality: From classic to multiplex networks. Chaos: An Interdisciplinary Journal of Nonlinear Science, 26(6), 065301. doi:10.1063/1.4952955Zachary, W. W. (1977). An Information Flow Model for Conflict and Fission in Small Groups. Journal of Anthropological Research, 33(4), 452-473. doi:10.1086/jar.33.4.362975

Ficología marina mexicana. Diversidad y Problemática actual

An analysis on marine macroalgal diversity in Mexico was done relating Chlorophyta, Rhodophyta and Phaeophyceae records with coastal Mexican states or geopolitical entities. Also, data were classify in species, genera, family and orders, and percentage of occurrence was evaluated in five different biogeographycal regions called: Western Baja California, Gulf of California, Tropical Pacífic, Gulf of México, and Caribbean. Most diverse states are Baja California in its western side, Baja California Sur, and Sonora in Pacific Mexico, Veracruz and Quintana Roo in Atlantic Ocean. Macroalgae high biodiversity was detected in transitional areas of Pacific Mexico and in the Caribbean area of Yucatán Peninsula. We discuss some inherent problems to this macroalgal biodiversity and threatening issues to it as alien species.Se analiza la situación del inventario de las macroalgas marinas mexicanas en ralación a las divisionesChlorophyta, Rhodophyta y a la clase Pheophyceae. La información se clasificó de acuerdo a los estados oentidades federativas de la Republica Mexicana que poseen costas en el Pacífico o Atlántico. También sediscuten las proporciones de géneros, familias y órdenes para las regiones costeras denominadas: BajaCalifornia occidental, Golfo de California, Pacífico tropical, Golfo de México y Caribe. Los estados que destacan por su diversidad son: Baja California, en su porción occidental, Baja California Sur y Sonora en cuanto al Pacífico; Veracruz y Quintana Roo para el Atlántico. Las regiones costeras por su parte muestran una biodiversidad alta en las áreas de transición del Pacífico y en la porción caribeña de la Península de Yucatán. Discutimos algunos de los problemas actuales que caracterizan a esta biodiversidad y la amenaza de las especies invasoras en su integridad

An Eigenvector Centrality for Multiplex Networks with Data

Networks are useful to describe the structure of many complex systems. Often, understanding these systems implies the analysis of multiple interconnected networks simultaneously, since the system may be modelled by more than one type of interaction. Multiplex networks are structures capable of describing networks in which the same nodes have different links. Characterizing the centrality of nodes in multiplex networks is a fundamental task in network theory. In this paper, we design and discuss a centrality measure for multiplex networks with data, extending the concept of eigenvector centrality. The essential feature that distinguishes this measure is that it calculates the centrality in multiplex networks where the layers show different relationships between nodes and where each layer has a dataset associated with the nodes. The proposed model is based on an eigenvector centrality for networks with data, which is adapted according to the idea behind the two-layer approach PageRank. The core of the centrality proposed is the construction of an irreducible, non-negative and primitive matrix, whose dominant eigenpair provides a node classification. Several examples show the characteristics and possibilities of the new centrality illustrating some applications.This research is partially supported by the Spanish Government, Ministerio de Economía y Competividad, grant number TIN2017-84821-P

A review of non-native seaweeds from California, USA and Baja California, Mexico

The seaweed flora of California, USA and Baja California, Mexico is a world-class treasure. The magnificent diversity and abundance of seaweed populations reflect the dramatic sweep of these rich coastal environments and habitats, from the Pacific Northwest to the subtropics, including rocky shores and reefs, sandy beaches, and offshore islands. Novel species have joined the flora, mostly via unintentional introductions of non-indigenous species by humans. Most of the 29 non-native seaweed species recorded from this coast originated in Asia. Many have been discovered within the last 30 years. Although the vectors that bring these plants or their propagules to the California and Baja California coasts (international shipping and shellfish aquaculture) may or may not be increasing within that time span, the conditions for the establishment of non-native species seem to have improved. Climate change, including the frequency and severity of ENSO events, may be responsible for creating space, diminishing competition, and permitting the persistence and spread of non-native species. Here we review these non-native seaweed species and speculate on the link between their establishment and climate change

Extending the Adapted PageRank Algorithm Centrality to Multiplex Networks with Data Using the PageRank Two-Layer Approach

Usually, the nodes’ interactions in many complex networks need a more accurate mapping than simple links. For instance, in social networks, it may be possible to consider different relationships between people. This implies the use of different layers where the nodes are preserved and the relationships are diverse, that is, multiplex networks or biplex networks, for two layers. One major issue in complex networks is the centrality, which aims to classify the most relevant elements in a given system. One of these classic measures of centrality is based on the PageRank classification vector used initially in the Google search engine to order web pages. The PageRank model may be understood as a two-layer network where one layer represents the topology of the network and the other layer is related to teleportation between the nodes. This approach may be extended to define a centrality index for multiplex networks based on the PageRank vector concept. On the other hand, the adapted PageRank algorithm (APA) centrality constitutes a model to obtain the importance of the nodes in a spatial network with the presence of data (both real and virtual). Following the idea of the two-layer approach for PageRank centrality, we can consider the APA centrality under the perspective of a two-layer network where, on the one hand, we keep maintaining the layer of the topological connections of the nodes and, on the other hand, we consider a data layer associated with the network. Following a similar reasoning, we are able to extend the APA model to spatial networks with different layers. The aim of this paper is to propose a centrality measure for biplex networks that extends the adapted PageRank algorithm centrality for spatial networks with data to the PageRank two-layer approach. Finally, we show an example where the ability to analyze data referring to a group of people from different aspects and using different sets of independent data are revealed.This research is partially supported by the Spanish Government, Ministerio de Economía y Competividad, grant number TIN2017-84821-P

SPONGITES YENDOI (FOSLIE) Y. CHAMBERLAIN (CORALLINALES, RHODOPHYTA) EN LA COSTA ATLÁNTICA DE MÉXICO Y CARIBE MEXICANO

In this work we report the occurrence ofSpongites yendoi (Foslie) Y. Chamberlain(Corallinaceae, Rhodophyta) from theAtlantic coast of Mexico and Mexican Caribbean. This is the first record ofS. yendoi in this geographic area. Theidentification was based on a morphologicalrevision of samples collected from severalreefs in Veracruz, Yucatan and QuintanaRoo. The vegetative and reproductivestructures as well habitat and distributionof this species are described.En el presente trabajo se cita la presencia deSpongites yendoi (Foslie) Y. Chamberlain(Corallinaceae, Rhodophyta) en la costaAtlántica de México y Caribe mexicano.Éste es el primer registro de S. yendoi enesta área geográfica. La determinaciónde los especímenes se basó en la revisiónmorfológica de muestras obtenidas en variosarrecifes de Veracruz, Yucatán y QuintanaRoo. Se describen las estructuras vegetativasy reproductoras así como el hábitat y ladistribución de esta especie

Dictyota chalchicueyecanensis sp. nov. (Dictyotales, Phaeophyceae) en el Golfo de México: evidencias moleculares y morfológicas

Background. Species of the Dictyota genus have a high phenotypic plasticity that contrasts with their limited morphological diagnostic characteristics, which has led to some uncertainty in identifying species in the Gulf of Mexico. Recent studies worldwide have focused on Dictyota species phylogenies, which are the basis for contrasting and interpreting the results of this study. Goals. In our research, we found evidence of a new species belonging to the Dictyota genus in three localities in the state of Veracruz, Mexico (Playa Hermosa, Punta Puntillas y Villa Rica). Methods. Phylogenetic andmolecular analyses of partial sequences of the psbA and cox1 genes were performed, complemented by morphological analysis. Results. In phylogenetic analysis of partial sequences of psbA and cox1, we established that samples of the new species form a well-supported monophyletic clade. In addition, the genetic divergence values that were obtained are within the interspecific values for the genus, allowing us to segregate the Dictyota chalchicueyecanensis sp. nov. from therest of the species of this genus. Morphologically this new species is characterized by an erect thallus, light brown and lacking iridescence, stiff to the touch, with a discoid holdfast, rounded apices, dichotomous branching, dentated margins, with minute teeth, triangular to spinose in shape that are directed toward the apices. Sporangia are isolated or grouped on both sides of the thallus and germinate regularly in interdichotomous basal portions. Conclusion. These results allow us to expand the diversity of the genus Dictyota worldwide, incorporating D. chalchicueyecanensis as a probable newspecies endemic to Mexico.Antecedentes. Las especies del género Dictyota presentan una alta plasticidad fenotípica que contrasta con escasos caracteres morfológicos diagnósticos, lo cual ha llevado a identificar especies con cierta incertidumbre en el Golfo de México. Estudios recientes a nivel mundial refieren filogenias de especies de Dictyota, los que serán la base para contrastar e interpretar los resultados de este estudio. Objetivos. En este trabajo se determina la presencia de una nueva especie para la ciencia del género Dictyota, encontrada en tres localidades del estado de Veracruz, México (Playa Hermosa, Punta Puntillas y Villa Rica). Métodos. Se realizaron análisis filogenéticos y moleculares de secuencias parciales de los genes psbA y cox1, que fueron complementados con análisis morfológicos. Resultados. En los análisis filogenéticos de las secuencias parciales de los genes psbA y cox1, se obtuvo que las muestras de la nueva especie forman un clado monofilético bien soportado. Además, los índices de divergencia genética obtenidos, se encuentran dentro de los valores interespecíficos para el género, lo que permite segregar a Dictyota chalchicueyecanensis sp. nov. de las demás especies del género. Morfológicamente esta nueva especie se caracteriza por presentar un talo erecto, sin iridiscencia, de consistencia rígida al tacto, con pie de fijación al sustrato de forma discoide, de color café claro in situ, ápices redondeados, amificación dicotómica, con márgenes dentados de forma triangular a espinosa dirigidos hacia los ápices. Esporangios aislados o agrupados en ambas superficies del talo que regularmente germinan en las porciones interdicotómicas basales del mismo. Conclusiones. Los resultados anteriores amplían la diversidad del género Dictyota a nivel mundial, incorporando a D. chalchicueyecanensis como una nueva especie probablemente endémica de México

Codium (Chlorophyta) species presented in the Galápagos Islands

Background. The Galápagos Islands have been the subject of numerous scientific expeditions. The chief source of information on their marine algae is the report published in 1945 by the late William Randolph Taylor on collections made by the Allan Hancock Pacific Expedition of 1934. Prior to this work, there were no published records of Codium from the Galápagos. Taylor recorder six species of Codium of which C. isabelae and C. santamariae were new descriptions. Goals. On the basis of collections made since 1939, we have reviewed the registry of Codium in these islands. Methods. Comparative analysis based on morphology and utricle anatomy. Results. Codium isabelae and C. santamariae are combined under the former name. Records of C. cervicorne and C. dichotomum also are referred to C. isabelae, those of C. setchellii are based partly on representatives of C. picturatum, a recently described species from the Mexican Pacific, Panama, Colombia, and Hawaii, and partly on representatives of a species similar if not identical to C. arabicum. The presence of C. foveolatum is corroborated. Codium fernandezianum, which was also reported by Taylor from the mainland of Ecuador, has been collected on Isla Santa Cruz. Conclusions. Five species of Codium are recognized from Galápagos Islands: C. arabicum, C. fernandezianum, C. foveolatum, C. isabelae and C. picturatum

Diagnóstico florístico de la ficología marina bentónica en Chiapas

The checklist of macroalgae for 17 localities in the coast of Chiapas involves 53 species, including 16 Chlorophyta, 8 Phaeophyta, and 29 species of Rhodophyta. From this list, 32 species grow in estuarine habitats. Floristic affinities between Chiapas estuaries and those from the Gulf of Mexico and north of Quintana Roo, together with the fossil record, suggest an early contact during the Eocene and Miocene. The presence of two red macroalgae (one of them not clearly classified) in the deep benthos from Chiapas off shore, confirm, biologically, the up-welling process detected at the area with physical and chemical techniques. Floristic affinities with the coasts of Oaxaca, Michoacán, Colima, Jalisco, Nayarit and Sinaloa, support the characterization of an area with strong interchange of tropical, sub tropical, and temperate elements. We called this phycofloristic-mosaic. We discuss on the possibilities of integrating theory of island biogeography to future phycological studies in estuarine habitats.El inventario de macroalgas para 17 localidades en el litoral de Chiapas se compone de 53 especies, incluyendo 16 Chlorophyta , 8 Phaeophyta y 29 Rhodophyta. De las 53 especies, 32 crecen en ambientes estuarinos. Las afinidades florísticas de los estuarios chiapanecos con aquellos del sur del Golfo de México y norte de Quintana Roo, junto al registro fósil, sugieren un contacto marino durante los períodos Eoceno y Mioceno. La presencia de dos macroalgas rojas (una de ellas aún no bien clasificada) en el bentos profundo frente a Chiapas confirma biológicamente la surgencia detectada por la oceanografía física y química. Las afinidades florísticas (Chlorophyta) de Chiapas con los estados de Oaxaca, Michoacán, Colima, Jalisco, Nayarit y Sinaloa, plantean la caracterización de una zona de intercambio de elementos templados y tropicales, para lo cual proponemos el concepto de Mosaico Ficoflorístico. Se revisa la posibilidad de integrar la teoría de biogeografía de islas para los estudios de macroalgas estuarinas