Estudio multivariado de la fluctuación espacio-temporal de la comunidad fitoplanctónica en dos lagunas costeras del estado de Chiapas

The spatio-temporal variation of the distribution and composition of the phytoplankton community was studied through a Principal Component Analysis (PCA) and a Cluster Analysis (CA). Based on the seasonal behavior of the most important hydrological factors and on the CA, it was established that the Carretas-Pereyra lagoon system varies throughout the year presenting eurihaline and polyhaline habitats during the dry season and mesohaline and polyhaline ones during the wet season. It was also established that in Chantuto-Panzacola the polihaline and eurihaline habitats of the dry season become polyhaline during the wet season while the mesohaline habitat remains unchanged throughout the whole year. The structure of the phytoplankton community is dependent by the key environmental characteristics of the seasonal habitats established in both systems, situation that generates a succession of the species. The PCA analysis showed that during the dry season there is a dominance of marine species (diatoms and dinoflagellates) distributed along the eurihaline habitat, but during the rainy season the community is made up by both, freshwater species (diatoms of the genera Navicula and cyanophytes) distributed along the mesohaline habitat and brackish species which are found throughout the polihaline habitat. Finally, a phytoplankton succession was established for both systems (Carretas-Pereyra and Chantuto-Panzacola): Dominance of Diatoms (dry season)-Dinoflagellates (dry-wet season)- Cyanophytes (wet season).Se estudió la comunidad fitoplanctónica de los sistemas lagunares Carretas-Pereyra y Chantuto-Panzacola del estado de Chiapas, realizando una caracterización espacial y en dos épocas del año de su distribución, composición y abundancia relativa, asociándola a las variaciones de las condiciones físico-químicas mediante el empleo del Análisis de Componentes Principales (ACP) y el Análisis de Conglomerados (AC). Con base en el comportamiento hidrológico estacional y en el AC se observó que el sistema Carretas-Pereyra varía a lo largo del año presentando habitats polihalinos a euhalinos en la época de secas y mesohalinos a polihalinos durante lluvias. También se evidenció que en Chantuto-Panzacola el habitat mesohalino permanece como tal durante ambas épocas mientras que los habitats polihalino y euhalino presentes en secas adquieren características polihalinas en lluvias. La estructura de la comunidad fitoplanctónica está condicionada por las características ambientales de los habitats establecidos en ambos sistemas, lo que origina una sucesión estacional en las especies que la componen. El ACP demostró que durante la época de secas se observa la dominancia de grupos de estirpe marina (diatomeas y dinoflagelados principalmente) distribuidos a lo largo del habitat euhalino, mientras que durante lluvias lacomunidad está integrada tanto por especies de agua dulce (diatomeas del género Navicula y cianofitasprincipalmente) distribuidas en el habitat mesohalino, como por especies con afinidades salobres que seencuentran en el habitat polihalino. Finalmente, puede establecerse que la sucesión en los sistemas Carretas-Pereyra y Chantuto-Panzacola sigue el siguiente orden: Dominancia de diatomeas (secas) -dinoflagelados (secaslluvias) cianofitas (lluvias)

Composición estacional del fitoplancton de dos lagunas costeras del Pacífico tropical

This paper presents the seasonal composition and distribution of the microphytoplankton comunity collected during the period 1997-2002 in two coastal lagoons, Chantuto-Panzacola (CH-P) and Carretas-Pereyra (C-P), located in the state of Chiapas, Mexico. A total of 199 and 125 taxa were identified in CH-P and C-P respectively; in both systems more than 60% of the composition was represented by diatoms, followed in order of importance by dinoflagellates, chlorophytes, cyanophytes, euglenophytes, and finally by silicoflagellates. The results of a Principal Components Analysis (PCA) of stations, based on the presence/absence of species, generated the discrimination of two analogous zones for each system. These zones correspond with the environmental gradient generated by physical and chemical variables like salinity and nutrients which explain more than 70% of the variance and allow the differentiation of two groups of communities: during dry season there was a dominance of alocthonous (neritic) phytoplankton like diatoms and dinoflagellates, distributed mainly in the zone of greater tidal influence; in the rainy season the community was integrated by freshwater groups (chlorophytes, cianophytes, and euglenophytes) as well as of diatoms with brackish affinities (Surirella spp.).El presente trabajo tuvo como objetivo determinar la distribución espacial y temporal del microfitoplancton, colectado durante el periodo de 1997 a 2002 en las lagunas costeras Chantuto-Panzacola (CH-P) y Carretas-Pereyra (C-P), Chiapas, en las dos épocas climáticas características de la región (secas y lluvias), así como las variables que determinan esta distribución. Se identificaron un total de 199 taxa en el sistema CH-P y 125 en C-P, en ambos sistemas más del 60% estuvo representado por las diatomeas, seguidas en orden de importancia por los dinoflagelados, clorofitas, cianofitas, euglenofitas y por último de los silicoflagelados. El análisis de similitud entre estaciones, basado en la presencia/ausencia de las especies, dio como resultado la discriminación de dos zonas análogas para cada sistema relacionadas con el gradiente ambiental generado por las variables físico-químicas de salinidad y nutrientes y determinado mediante un Análisis de Componentes Principales (ACP); estas variables explican más del 70% de la varianza y permiten la diferenciación de dos grupos de comunidades: durante la época de secas se observó la dominancia de grupos fitoplanctónicos alóctonos como diatomeas y dinoflagelados, distribuidos principalmente en el zona de mayor influencia mareal; en la temporada de lluvias la comunidad estuvo integrada por grupos dulceacuícolas (clorofitas, cianofitas y euglenofitas), así como de diatomeas con afinidades salobres (Surirella spp.)

Caracterización estacional de las condiciones físico-químicas y de productividad primaria fitoplanctónica de dos lagunas costeras tropicales del estado de Chiapas, México

The objective of this study was to evaluate in several months, the main environmental variables and the phytoplankton biomass and production of two coastal lagoons in the state of Chiapas, and to determine the possible differences between the two main climatic seasons. The study was carried out during several yearly cycles (1990-1991; 1997- 2003). The results show that the discharge of the main rivers flowing into these lagoons determines the establishment of different environmental characteristics during the main climatic seasons, dry and wet. During the dry season, the limited fluvial input, together with the tidal influence, generates stable environmental conditions, characterized by high temperatures and salinities, and high nutrient concentrations which favor high phytoplankton biomass and production. On the contrary, during the wet season, river input diminish salinities and increases nutrients which are used by the phytoplankton, promoting high biomasses and productions. However, due to the low residence time, many of this materials are exported out of the system to the adjacent coastal zone.El objetivo de este trabajo fue el de evaluar en diferentes meses las principales variables ambientales, así como la biomasa y productividad primaria fitoplanctónica en dos lagunas costeras del estado de Chiapas, así como determinar sus posibles diferencias entre las dos épocas climáticas características de la región. El estudio abarcó varios ciclos anuales (1990-1991; 1997-2003). Los resultados muestran que las descargas de los principales ríos que desembocan en las lagunas determinan el establecimiento en las lagunas de características ambientales distintas para las dos principales épocas climáticas, secas y lluvias. Durante secas, la disminución de la precipitación y como consecuencia la baja influencia fluvial, aunada al intercambio mareal, genera en la laguna altas temperaturas y salinidades, así como concentraciones elevadas de nutrientes, que favorecen una alta biomasa y productividad primaria fitoplanctónica. En el caso de la época de lluvias, el alto aporte fluvial disminuye la salinidad e introduce nutrientes al sistema que son utilizados por el fitoplancton, favoreciendo también altas biomasas y productividades; sin embargo, debido al bajo tiempo de residencia, muchos de estos materiales son acarreados fuera del sistema hacia la zona costera adyacente

Prokaryotic picoplankton distribution within the oxygen minimum zone of the central Mexican Pacific across environmental gradients

O picophytoplankton marinho tornou-se uma questão importante para compreender a ecologia global das formas fototróficas, devido à sua ampla distribuição e contribuição para a biomassa e a produtividade. Estudamos os pigmentos de abundância, distribuição e assinatura do picofitoplâncton procarionte Prochlorococcus e Synechococcus durante um cruzeiro oceanográfico no Pacífico central mexicano, uma zona mínima de oxigênio relativamente poco conhecida (OMZ) e o efeito de três gradientes ambientais. As abundâncias de Prochlorococcus e Synechococcus foram comparáveis às encontradas em outras áreas tropicais (0.17 to 30.37 X 104 células mL1, e 0.9 to 30.97 X 104 células mL-1, respectivamente). As abundâncias de Prochlorococcus atingiram o maior número em águas mais profundas, coincidindo frequentemente com a segunda intensidade de fluorescência in situ profunda (e clorofila a), em estações oceânicas, abaixo da nitratoclina, enquanto as abundâncias de Synechococcus foram maiores nas águas de subsuperficie e sua concentração máxima geralmente coincidiu com os máximos de subsuperficie de fluorescência in situ, com abundâncias ligeiramente mais altas nas estações costeiras. As análises estatísticas suportam significativamente esses resultados. A distribuição da divinil-clorofila a foi errática ao longo da coluna de água e coincidiu ocasionalmente com os máximos de fluorescência in situ profundos, enquanto que a distribuição da zeaxantina seguiu geralmente a da clorofila a e as abundâncias de Synechococcus e atingiu o pico. Estes resultados são semelhantes aos encontrados anteriormente na área de estudo e em zonas mais temperadas, e também à tendência geral na OMZ, mas confirmam que a clorofila profunda a maxima é atribuída a altas densidades de Prochlorococcus. Além disso, encontramos a abundância e distribuição de Prochlorococcus e Synechococcus fortemente conduzida pelos gradientes ambientais observados.Marine picophytoplankton has become an important issue to understand the global ecology of phototrophic forms, due to its wide distribution and contribution to biomass and productivity. We studied the abundance, distribution and signature pigments of the prokaryote picophytoplankters Prochlorococcus and Synechococcus during an oceanographic cruise (26 April to 7 May, 2011) in the central Mexican Pacific, a relatively poorlyknown oxygen minimum zone (OMZ), and the effect of three environmental gradients. Prochlorococcus and Synechococcus abundances were comparable with those found in other tropical areas (0.17 to 30.37 X 104 cells mL-1, and 0.9 to 30.97 X 104 cells mL-1, respectively). Prochlorococcus abundances reached highest numbers in deeper waters, often coinciding with the second deep in situ fluorescence (and chlorophyll α) maxima, at oceanic stations, below the nitratecline, whereas Synechococcus abundances were higher at subsurface waters and its concentration maxima usually coincided with the subsurface in situ fluorescence maxima, with slightly higher abundances in coastal stations. Statistical analyses support significantly these results. Distribution of divinyl-chlorophyll α was erratic along the water column and occasionally coincided with the deep in situ fluorescence maxima, whereas the distribution of zeaxanthin usually followed that of chlorophyll α and the abundances of Synechococcus, and peaked together. These results are similar to those previously found in the study area and in more temperate zones, and also to the general trend in OMZ, but confirm that the second deep chlorophyll α maxima are attributed to high Prochlorococcus densities. We additionally found the abundance and distribution of Prochlorococcus and Synechococcus strongly driven by the environmental gradients observed

Co-ocurrencia de dos dinoflagelados tóxicos en la Bahía de Acapulco, Guerrero, México: una oportunidad para cuantificar su biología y ecología

Background and Aims: Harmful Algal Blooms (HAB) commonly occur in the Mexican Pacific, being important HABs of Gymnodinium catenatum (Gc) and of Pyrodinium bahamense var. compressum (Pbc) for being saxitoxin-producing dinoflagellates that cause paralytic shellfish poisoning. The latter is a taxon that sporadically occurs in the tropical Mexican Pacific. This study describes the behavior of both taxa throughout the annual cycle and analyzes their morphology, abundance, distribution, and their bloom dynamics, in relation to environmental and climatological parameters. Methods: Phytoplankton collections were made ten times from October 2009 to January 2011 within Acapulco Bay and its surroundings, together with measurements of physicochemical parameters. Climatic data were obtained from Acapulco weather station. Abundance of phytoplankton was evaluated with the Utermöhl method. Statistical analyses were carried out to investigate the relationship of Gc and Pbc abundances with environmental and climatic parameters. Key results: Gc was present throughout the year 2010 in low densities and in November 2010 it reached a maximum of 189×103 cells l-1, associated with several species of diatoms and dinoflagellates, including Pbc. Gc bloom coincides with decrease in ammonium and decrease in water temperature with respect to the average. Pyrodinium bahamense morphometry from Acapulco corresponds to var. compressum. Pbc formed an intense HAB in July 2010 (reaching a maximum abundance of 773×103 cells l-1), causing significant toxicity and had an upturn in November. Conclusions: Pbc HABs in Acapulco require the occurrence of a previous HAB in the central Pacific or Gulf of Tehuantepec, Mexico, horizontal transportation of their cysts, as well as high water temperature conditions, abundant rainfall that increased the concentration of phosphates, which is propitiated in the periods of transition "El Niño"-"La Niña" events. Gc HABs in Acapulco are related to "La Niña" events, with an abrupt change in water temperature and an increase in nitrogenous forms.Antecedentes y Objetivos: Los florecimientos algales nocivos (FAN) ocurren comúnmente en el Pacífico mexicano, siendo importantes los de Gymnodinium catenatum (Gc) y Pyrodinium bahamense var. compressum (Pbc), dinoflagelados productores de saxitoxina que causan envenenamiento paralítico por mariscos. Pbc se presenta esporádicamente en el Pacifico tropical mexicano. El estudio describe el comportamiento de ambos taxa en un ciclo anual y analiza su morfología, abundancia, distribución y dinámica del FAN en relación con parámetros ambientales y climatológicos. Métodos: Se realizaron diez recolectas de fitoplancton, (octubre 2009-enero 2011) en la Bahía de Acapulco y zona costera adyacente, y mediciones de parámetros fisicoquímicos. Los datos climáticos se obtuvieron de la estación meteorológica de Acapulco. La abundancia del fitoplancton se evaluó con el método de Utermöhl. Se realizaron análisis estadísticos para investigar la relación de las abundancias de Gc y Pbc con parámetros ambientales y climáticos. Resultados clave: Gc estuvo presente durante todo el año 2010 con densidades bajas; en noviembre de 2010 alcanzó un máximo de 189×103 células l-1, asociado con especies de diatomeas y dinoflagelados, incluyendo Pbc. El florecimiento de Gc coincidió con disminución de amonio, y disminución de temperatura del agua con respecto al promedio. La morfometría de Pb de Acapulco correspondió con la var. compressum. Pbc formó un intenso FAN en julio de 2010 (abundancia máxima de 773×103 células l-1), causando una toxicidad significativa y tuvo un repunte en noviembre. Conclusiones: Los FAN de Pbc en Acapulco requieren un FAN previo en el Pacífico central o en el Golfo de Tehuantepec, transporte horizontal de sus quistes, alta temperatura del agua y abundante precipitación que aumente la concentración de fosfatos; condiciones que propician en los períodos de transición"El Niño"-"La Niña". Los FAN de Gc en Acapulco están relacionados con eventos "La Niña", siendo importantes el cambio abrupto de temperatura del agua y el aumento de formas nitrogenadas

Dynamics and fractal dimension of Steffensen-type methods

In this paper, the dynamical behavior of different optimal iterative schemes for solving nonlinear equations with increasing order, is studied. The tendency of the complexity of the Julia set is analyzed and referred to the fractal dimension. In fact, this fractal dimension can be shown to be a powerful tool to compare iterative schemes that estimate the solution of a nonlinear equation. Based on the box-counting algorithm, several iterative derivative-free methods of different convergence orders are compared.Chicharro López, FI.; Cordero Barbero, A.; Torregrosa Sánchez, JR. (2015). Dynamics and fractal dimension of Steffensen-type methods. Algorithms. 8(2):271-279. doi:10.3390/a8020271S27127982Kung, H. T., & Traub, J. F. (1974). Optimal Order of One-Point and Multipoint Iteration. Journal of the ACM, 21(4), 643-651. doi:10.1145/321850.321860Varona, J. L. (2002). Graphic and numerical comparison between iterative methods. The Mathematical Intelligencer, 24(1), 37-46. doi:10.1007/bf03025310Amat, S., Busquier, S., Bermúdez, C., & Plaza, S. (2012). On two families of high order Newton type methods. Applied Mathematics Letters, 25(12), 2209-2217. doi:10.1016/j.aml.2012.06.004Blanchard, P. (1984). Complex analytic dynamics on the Riemann sphere. Bulletin of the American Mathematical Society, 11(1), 85-142. doi:10.1090/s0273-0979-1984-15240-6Cordero, A., Hueso, J. L., Martínez, E., & Torregrosa, J. R. (2013). A new technique to obtain derivative-free optimal iterative methods for solving nonlinear equations. Journal of Computational and Applied Mathematics, 252, 95-102. doi:10.1016/j.cam.2012.03.030Epureanu, B. I., & Greenside, H. S. (1998). Fractal Basins of Attraction Associated with a Damped Newton’s Method. SIAM Review, 40(1), 102-109. doi:10.1137/s003614459631003

Fitoplancton en el sistema lagunar tropical Carmen Pajonal Machona, Tabasco

Background. Phytoplankton is considered an important indicator of natural and anthropogenic processes that take place in basins and coastal environments. An example of these systems is the formed by the El Car- men, Pajonal and La Machona lagoons, in which there is intense fishing and oyster farming activity, as well as agricultural activities, oil extraction and forestry in their surroundings. Goals.Identifying the phytoplankton species, with emphasis on the potentially harmful and / or toxic ones, their distribution and differences between the samplings, north winds (2015) and rainy (2016), as well as reporting the physicochemical variables was the aimed of this work. Methods. Net samples with a mesh size of 20 μm were taken and physicoche- mical variables were measured with a water quality sonde. 300 organisms were counted and the specific richness, relative abundances and diversity index were calculated. To identify differences between the two seasons sampled the Mann-Whitney U test was performed. In addition, the most important physicochemical variables were identified to explore their relationship with the species through a distance-based redundancy analysis (dbRDA). Results. A total of 86 species were identified, of which ten are new records and 15 are potentially harmful and / or toxic ones. The taxonomic group with the most species in both seasons was Bacillaryophyta (43 Northeast and 22 Rains). Specific richness was significantly different between seasons. In the north winds season, the most abundant species were from the Cyanoprokaryota and Bacillaryophyta groups, while for rainy season they were from the Dinoflagellata. Conclusions. Water temperature and salinity were the physicochemical variables that defined the phyto- plankton composition in the CPM lagoons; the presence of potentially toxic species is an alert for the lagoon system because it reflects a latent situation that could trigger blooms at any time.Antecedentes. El fitoplancton es considerado un indicador importante de los procesos naturales y antro- pogénicos que se desarrollan en las cuencas y en los ambientes costeros. Un ejemplo de estos sistemas es el conformado por las lagunas El Carmen, Pajonal y La Machona (CPM), en las cuales hay una intensa actividad pesquera y de ostricultura, así como actividades agrícolas, extracción petrolera y forestal a sus alrededores. Objetivo. El objetivo fue identificar las especies fitoplanctónicas, con énfasis en las potencial- mente nocivas y/o tóxicas, su distribución y diferencias entre los muestreos, nortes (2015) y lluvias (2016), así como reportar las variables fisicoquímicas. Métodos. Se tomaron muestras de red de 20 μm de abertura de malla y midieron las variables con una sonda de calidad de agua. Se contabilizaron 300 organismos y se obtuvieron la riqueza específica, abundancias relativas e índice de diversidad. Para identificar diferencias entre las dos temporadas muestreadas se realizó la prueba U de Mann-Whitney. Además, se identificaron las variables fisicoquímicas más importantes para explorar su relación con las especies mediante un análisis de redundancia basado en distancias (dbRDA). Resultados. Se identificaron un total de 86 especies de las cuales diez son nuevos registros para el área y 15 son potencialmente tóxicas. El grupo taxonómico con más especies fue el de las Bacillaryophyta (43 nortes y 22 lluvias). La riqueza específica fue significativamente diferente entre temporadas. Las especies más abundantes fueron de los grupos de las Cyanoprokaryota y las Bacillaryophyta para la temporada de nortes, mientras que para la temporada de lluvias fueron del grupo Dinoflagellata. Conclusiones. La temperatura y la salinidad fueron las variables que determinaron la com- posición del fitoplancton en las lagunas CPM; la presencia de especies potencialmente tóxicas es una alerta para el sistema lagunar debido a que refleja una situación latente que podría desencadenar florecimientos en cualquier momento

Expression and activity profiles of DPP IV/CD26 and NEP/CD10 glycoproteins in the human renal cancer are tumor-type dependent

[Background] Cell-surface glycoproteins play critical roles in cell-to-cell recognition, signal transduction and regulation, thus being crucial in cell proliferation and cancer etiogenesis and development. DPP IV and NEP are ubiquitous glycopeptidases closely linked to tumor pathogenesis and development, and they are used as markers in some cancers. In the present study, the activity and protein and mRNA expression of these glycoproteins were analysed in a subset of clear-cell (CCRCC) and chromophobe (ChRCC) renal cell carcinomas, and in renal oncocytomas (RO).[Methods] Peptidase activities were measured by conventional enzymatic assays with fluorogen-derived substrates. Gene expression was quantitatively determined by qRT-PCR and membrane-bound protein expression and distribution analysis was performed by specific immunostaining.Peer reviewe

First measurement of the Hubble Constant from a Dark Standard Siren using the Dark Energy Survey Galaxies and the LIGO/Virgo Binary–Black-hole Merger GW170814

International audienceWe present a multi-messenger measurement of the Hubble constant H 0 using the binary–black-hole merger GW170814 as a standard siren, combined with a photometric redshift catalog from the Dark Energy Survey (DES). The luminosity distance is obtained from the gravitational wave signal detected by the Laser Interferometer Gravitational-Wave Observatory (LIGO)/Virgo Collaboration (LVC) on 2017 August 14, and the redshift information is provided by the DES Year 3 data. Black hole mergers such as GW170814 are expected to lack bright electromagnetic emission to uniquely identify their host galaxies and build an object-by-object Hubble diagram. However, they are suitable for a statistical measurement, provided that a galaxy catalog of adequate depth and redshift completion is available. Here we present the first Hubble parameter measurement using a black hole merger. Our analysis results in , which is consistent with both SN Ia and cosmic microwave background measurements of the Hubble constant. The quoted 68% credible region comprises 60% of the uniform prior range [20, 140] km s−1 Mpc−1, and it depends on the assumed prior range. If we take a broader prior of [10, 220] km s−1 Mpc−1, we find (57% of the prior range). Although a weak constraint on the Hubble constant from a single event is expected using the dark siren method, a multifold increase in the LVC event rate is anticipated in the coming years and combinations of many sirens will lead to improved constraints on H 0

Search for gravitational waves from Scorpius X-1 in the second Advanced LIGO observing run with an improved hidden Markov model

We present results from a semicoherent search for continuous gravitational waves from the low-mass x-ray binary Scorpius X-1, using a hidden Markov model (HMM) to track spin wandering. This search improves on previous HMM-based searches of LIGO data by using an improved frequency domain matched filter, the J-statistic, and by analyzing data from Advanced LIGO's second observing run. In the frequency range searched, from 60 to 650 Hz, we find no evidence of gravitational radiation. At 194.6 Hz, the most sensitive search frequency, we report an upper limit on gravitational wave strain (at 95% confidence) of h095%=3.47×10-25 when marginalizing over source inclination angle. This is the most sensitive search for Scorpius X-1, to date, that is specifically designed to be robust in the presence of spin wandering. © 2019 American Physical Society