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Search Results: 1 - 10 of 11016 matches for " Elena Solana Arellano "
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Utilización de métodos cuantitativos para el estudio de la dinámica de los pastos marinos: Una revisión crítica
Solana-Arellano,Elena;
Revista de biología marina y oceanografía , 2001, DOI: 10.4067/S0718-19572001000200005
Abstract: a revision of quantitative methods applied to the study of the dynamics of seagrasses populations is presented. included are the most important models used to describe growth, age, demography and density. in some cases, modifications to the existing models are proposed. suggestions for future research are also posted rendered.
Shoot Biomass Assessments of the Marine Phanerogam Zostera marina for Two Methods of Data Gathering  [PDF]
Elena Solana-Arellano, Héctor Echavarría-Heras, Victoria Díaz-Casta?eda, Olga Flores-Uzeta
American Journal of Plant Sciences (AJPS) , 2012, DOI: 10.4236/ajps.2012.311186
Abstract: In order to compare to data gathering methods for shoot biomass assessments of Zostera marina, we compare two allometric models each one representing a data gathering method, one at leaf level and the other in aggregated form. The first allometric model presented leaf dry weight in terms of leaf length as . The second model is expressed as a several-variables version of the allometric Equation (1) dry weight of each leaf in a given shoot can be considered to be a random variable therefore shoot biomass ws can be represented in the form Both models presented similar determination coefficients values of 0.85 and 0.87 respectively. We found no significant differences between parameters α (p = 0.11) and β (p = 0.50) fitted for each model, showing that both equations conduced to the same result. Moreover, both fitted models presented high Concordance Correlation Coefficients of reproducibility () (0.92 and 0.91). We concluded that for shoot weight assessments if larger samples and faster data processing is required then should model of Equation (2) be used. On the other hand, we proposed model of Equation (1) if data at leaf level is required for other endeavors.
Presence of Sargassum horneri at Todos Santos Bay, Baja California, Mexico: Its Effects on the Local Macroalgae Community  [PDF]
Giuliana I. Cruz-Trejo, Silvia E. Ibarra-Obando, Luis E. Aguilar-Rosas, Miriam Poumian-Tapia, Elena Solana-Arellano
American Journal of Plant Sciences (AJPS) , 2015, DOI: 10.4236/ajps.2015.617271
Abstract: To describe the annual cycle of Sargassum horneri in Mexican waters, we selected two sites differing in their degree of wave exposure and sediment type: Rincón de Ballenas (RB), and Rancho Packard (RP). From June 2009 to April 2010 we followed the seasonal changes in S. horneri density and biomass along two intertidal transects per site. The effects of this non-indigenous species on the local macroalgae community were assessed by comparing their species composition, density, biomass, species richness, and diversity index in quadrats with and without S. horneri. There were significant differences in S. horneri density and biomass between sites (P < 0.001). At RB the invasive alga density average was 2 ± 0.94 individual m-2, with a mean biomass of 4 ± 0.95 g DW m-2. At RP, S. horneri density average was 10 ± 0.96 individual m-2, and mean biomass of 102 ± 0.97 g DW m-2. At RB, the invasive alga promoted a significant reduction in the four selected structural variables, and the corticated macrophytes and the foliose functional forms were severely reduced. At RP, there were only marginally significant effects (P = 0.06) of S. horneri presence on the local macroalgae community, and higher density, biomass, and diversity values were found when S. horneri was present. Most of the functional forms were found, even if the invasive alga was present. At both locations, the highest biomass corresponded to the articulated calcareous functional form. These contrasting results could be due to the fact that the native macroalgae community has already been altered by the early invasion of S. muticum, with the most resilient species and functional forms remaining in place. One of the most important changes we noticed is the severe reduction of the canopy forming species at both sites.
An economical non-destructive method for estimating eelgrass, Zostera marina (Potamogetonaceae) leaf growth rates: formal development and use in northwestern Baja California
Solana-Arellano,Elena; Echavarria-Heras,Héctor; Franco-Vizcaíno,Ernesto;
Revista de Biología Tropical , 2008,
Abstract: seagrass beds provide much of the primary production in estuaries; host many fishes and fish larvae, and abate erosion. the present study presents original analytical methods for estimating mean leaf-growth rates of eelgrass (zostera marina). the method was calibrated by using data collected in a z. marina meadow at punta banda estuary in baja california, mexico. the analytical assessments were based on measurements of leaf length and standard regression procedures. we present a detailed explanation of the formal procedures involved in the derivation of these analytical methods. the measured daily leaf-growth rate was 10.9 mm d-1 leaf-1. the corresponding value projected by our method was 10.2 mm d-1 leaf-1. the associated standard errors were of 0.53 and 0.56 mm d-1 leaf-1 respectively. the method was validated by projecting leaf-growth rates from an independent data set, which gave consistent results. the use of the method to obtain the mean leaf growth rate of a transplanted plot is also illustrated. comparison of our leaf-growth data with previously reported assessments show the significant forcing of sea-surface temperature on eelgrass leaf dynamics. the formal constructs provided here are of general scope and can be applied to equivalent eelgrass data sets in a straightforward manner. rev. biol. trop. 56 (3): 1003-1013. epub 2008 september 30.
An upgraded method to relocate marked shoots of the seagrass Zostera marina
Solana-Arellano,Elena; Echavarria-Heras,Hector; Flores-Uzeta,Olga;
Revista de Biología Tropical , 2000,
Abstract: this paper presents a new method for the recovery of marked seagrass blades. the introduction of a plastic belt surrounding the marked shoot at a sediment level provided a relocation arrangement which was unloosed by drag forces or grazing. the relocation method was tested on zostera marina l. it proved to have the advantage of increasing dramatically the number of marked shoots recovered up to 100% while reducing the cost of the procedure to a minimum. an allometric model indicated that the introduced relocation method has no impact on the development of the plant.
Mortality rate estimation for eelgrass Zostera marina (Potamogetonaceae) using projections from Leslie matrices
Flores Uzeta,Olga; Solana Arellano,Elena; Echavarría Heras,Héctor;
Revista de Biología Tropical , 2008,
Abstract: the main goal of this study is to provide estimations of mean mortality rate of vegetative shoots of the seagrass zostera marina in a meadow near ensenada baja california, using a technique that minimizes destructive sampling. using cohorts and leslie matrices, three life tables were constructed, each representing a season within the period of monthly sampling (april 1999 to april 2000). ages for the cohorts were established in terms of plastochrone interval (pi). the matrices were projected through time to estimate the mean total number of individuals at time t, n(t) as well as mortality. we found no statistical differences between observed and predicted mean values for these variables (t=-0.11, p=0.92 for n(t) and t=0.69, p=0.5 for mean rate of mortality). we found high correlation coefficient values between observed and projected values for monthly number of individuals (r=0.70, p=0.007) and monthly mortality rates (r=0.81, p=0.001). if at a certain time t a sudden environmental change occurs, and as long as the perturbation does not provoke the killing of all the individuals of a given age i for 0 ≤ i ≤ x - 1, there will be a prevailing number of individuals of age or stage x at a time t+1. this nondestructive technique reduces the number of field visits and samples needed for the demographic analysis of z. marina, and therefore decreases the disturbance caused by researches to the ecosystem. rev. biol. trop. 56 (3): 1015-1022. epub 2008 september 30
An upgraded method to relocate marked shoots of the seagrass Zostera marina
Elena Solana-Arellano,Hector Echavarria-Heras,Olga Flores-Uzeta
Revista de Biología Tropical , 2000,
Abstract: This paper presents a new method for the recovery of marked seagrass blades. The introduction of a plastic belt surrounding the marked shoot at a sediment level provided a relocation arrangement which was unloosed by drag forces or grazing. The relocation method was tested on Zostera marina L. It proved to have the advantage of increasing dramatically the number of marked shoots recovered up to 100% while reducing the cost of the procedure to a minimum. An allometric model indicated that the introduced relocation method has no impact on the development of the plant.
Mortality rate estimation for eelgrass Zostera marina (Potamogetonaceae) using projections from Leslie matrices
Olga Flores Uzeta,Elena Solana Arellano,Héctor Echavarría Heras
Revista de Biología Tropical , 2008,
Abstract: The main goal of this study is to provide estimations of mean mortality rate of vegetative shoots of the seagrass Zostera marina in a meadow near Ensenada Baja California, using a technique that minimizes destructive sampling. Using cohorts and Leslie matrices, three life tables were constructed, each representing a season within the period of monthly sampling (April 1999 to April 2000). Ages for the cohorts were established in terms of Plastochrone Interval (PI). The matrices were projected through time to estimate the mean total number of individuals at time t, n(t) as well as mortality. We found no statistical differences between observed and predicted mean values for these variables (t=-0.11, p=0.92 for n(t) and t=0.69, p=0.5 for mean rate of mortality). We found high correlation coefficient values between observed and projected values for monthly number of individuals (r=0.70, p=0.007) and monthly mortality rates (r=0.81, p=0.001). If at a certain time t a sudden environmental change occurs, and as long as the perturbation does not provoke the killing of all the individuals of a given age i for 0 ≤ i ≤ x - 1, there will be a prevailing number of individuals of age or stage x at a time t+1. This nondestructive technique reduces the number of field visits and samples needed for the demographic analysis of Z. marina, and therefore decreases the disturbance caused by researches to the ecosystem. Rev. Biol. Trop. 56 (3): 1015-1022. Epub 2008 September 30 El propósito principal de este estudio es el de proveer estimaciones de tasas promedio de mortalidad de tallos vegetativos de Zostera marina en una pradera cercana a Ensenada Baja California, utilizando una técnica que minimiza los muestreos destructivos para estos pastos marinos. Mediante la utilización de cohortes y matrices de Leslie, se construyeron tres tablas de vida, cada una representando a una estación dentro de período anual de muestreos mensuales (Abril 1999 a Abril 2000). Las edades de los cohortes fueron estimadas en términos de Intervalos de Plastocrono (IP). Las matrices de Leslie fueron proyectadas a través del tiempo para estimar el número total de individuos a un tiempo t, n(t) así como las tasas de mortalidad. No se encontraron diferencias significativas entre los valores medios observados y proyectados para estas variables (t=0.11, p=0.92 para n(t) y t=0.69, p=0.5 para la tasa media de mortalidad). Se encontraron altas correlaciones los valores observados y proyectados tanto en el número de individuos (r=0.70, p=0.007) como las tasas mensuales de mortalidad (r=0.81, p=0.001). Si a ci
An economical non-destructive method for estimating eelgrass, Zostera marina (Potamogetonaceae) leaf growth rates: formal development and use in northwestern Baja California
Elena Solana-Arellano,Héctor Echavarria-Heras,Ernesto Franco-Vizcaíno
Revista de Biología Tropical , 2008,
Abstract: Seagrass beds provide much of the primary production in estuaries; host many fishes and fish larvae, and abate erosion. The present study presents original analytical methods for estimating mean leaf-growth rates of eelgrass (Zostera marina). The method was calibrated by using data collected in a Z. marina meadow at Punta Banda estuary in Baja California, Mexico. The analytical assessments were based on measurements of leaf length and standard regression procedures. We present a detailed explanation of the formal procedures involved in the derivation of these analytical methods. The measured daily leaf-growth rate was 10.9 mm d-1 leaf-1. The corresponding value projected by our method was 10.2 mm d-1 leaf-1. The associated standard errors were of 0.53 and 0.56 mm d-1 leaf-1 respectively. The method was validated by projecting leaf-growth rates from an independent data set, which gave consistent results. The use of the method to obtain the mean leaf growth rate of a transplanted plot is also illustrated. Comparison of our leaf-growth data with previously reported assessments show the significant forcing of sea-surface temperature on eelgrass leaf dynamics. The formal constructs provided here are of general scope and can be applied to equivalent eelgrass data sets in a straightforward manner. Rev. Biol. Trop. 56 (3): 1003-1013. Epub 2008 September 30. Las praderas de pastos marinos abaten la erosión y aportan gran parte de la productividad primaria de los esteros y son refugio de muchos peces y sus larvas. El presente trabajo introduce métodos analíticos para estimar las tasas medias de crecimiento foliar de Zostera marina L. y sus varianzas. La calibración del método se llevó a cabo utilizando datos de una pradera de esta fanerógama en el Estero de Punta Banda Baja California, México. Las referidas estimaciones analíticas, se basan en medias de longitud foliar y en procedimientos estandarizados de regresión. Dichas determinaciones son por ende no-destructivas. Se proporciona una explicación detallada de los aspectos formales de la derivación del método. El valor promedio observado de la tasa media diaria de crecimiento foliar fue de 10.9 mm d-1 leaf-1. El valor correspondiente proyectado mediante nuestro método fue de 10.2 mm d-1 leaf-1. Los errores estándar asociados fueron 0.53 y 0.56 mm d-1 leaf-1 respectivamente. Valores proyectados de la tasa media de crecimiento foliar diario utilizando datos de longitudes foliares publicadas por otros autores dieron también resultados consistentes. Se ilustra también el uso del método para proyectar la media de cr
La evaluación del riesgo de las plantas transgénicas: de la regulación a la bioética
Arriaga Arellano,Elena; Linares Salgado,Jorge E.;
Revista de Bioética y Derecho , 2013,
Abstract: despite the regulations there are no mandatory nor official guidelines for establishing the minimum elements for environmental risk assessment (era) of gm crops. criteria for decision making have not been defined, and there are no peer-reviewed scientific nor socio - economic studies showing the benefits and risks of these products in comparison with the use of other technologies in agriculture. this situation has raised an "artificial uncertainty" related to transgenic crops and in this paper we propose a more sustainable strategy by including a bioethical soundness era.
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