oalib

Publish in OALib Journal

ISSN: 2333-9721

APC: Only $99

Submit

Any time

2019 ( 581 )

2018 ( 1138 )

2017 ( 1075 )

2016 ( 1469 )

Custom range...

Search Results: 1 - 10 of 613540 matches for " Oscar A; López-Martínez "
All listed articles are free for downloading (OA Articles)
Page 1 /613540
Display every page Item
Population characteristics of spotted rose snapper lutjanus guttatus caught as shrimp bycatch in the gulf of California
González-Ochoa,Oscar A; López-Martínez,Juana; Hernández-Saavedra,Norma Yolanda;
Interciencia , 2009,
Abstract: there are limited population biology studies of the spotted rose snapper lutjanus guttatus. adults of this highly valued commercial species are fished with gillnets and hook-and-line, while juveniles are caught as shrimp bycatch and usually discarded. the effects of this practice have not been studied. as a first step, this study assessed some population parameters of juvenile snapper caught by the gulf of california shrimp fishery. we looked for early growth stages and determined by the least squares method the weight to standard length relationship as w= 0.000092, sl3.0509. length frequency distributions were constructed; using the elefan i method, von bertalanffy growth parameters were found to be l¥= 515mm (standard length) and k= 0.13. natural mortality (m= 0.35) was estimated from pauly?s empirical and ralston equations; and total mortality was calculated by the catch curve equation. the recruitment pattern extended throughout the year, with spring and summer peaks. the sex ratio was 1:1 and the length at capture was 80mm (standard length). with an apparently high fishing mortality levels, it is recommended that abundance and distribution studies be performed to determine the impact of shrimp fishing on this population.
Darkedge midshipman Porichthys analis (Batrachoidiformes: Batrachoididae), a common shrimp-bycatch fish from the Gulf of California
Oscar A. González-Ochoa,Juana López-Martínez,Norma Y. Hernández-Saavedra
Revista de Biología Tropical , 2012,
Abstract: Shrimp fishery bycatch of the Gulf of California constitutes a wide variety of highly unknown fish, crustacean, and mollusk species with very low or null economic value, in contrast to those of commercial interest. However, there are no studies yet on the role of these low economic valued species have in the community structure and function, together with their possible effect on commercial populations. With the aim of contributing to the knowledge of Darkedge Midshipman fish Porichthys analis, the most common waste species in this fishery, we estimated some population characteristics. For this purpose, we obtained shrimp-bycatch fish during the 2004-2005 fishing season and performed some research surveys. A total of 1 725 Darkedge Midshipman were captured from 350 bycatch samples. Individual size ranged from 43-352mm SL. The weight to standard length relationship was determined as W=0.000092SL3.0509. Von Bertalanffy’s growth coefficient indicated a moderate growth rate (K=0.5) with an estimated asymptotic length ofL∞=352mm standard length, and a longevity of 6yr. Natural mortality was estimated as 0.97 and total mortality as 4.67. The recruitment pattern, as estimated by ELEFAN II, was extended over the year, peaking during spring and summer seasons. Sexual proportion of male:female was 1.65:1. Mature organisms appeared from August to March, and length at maturity was 157mm SL, which is larger than the mean size at capture 135mm SL. We concluded that the species is indirectly protected by its own bathymetric distribution and the off-shrimping season. This is the first study that considers population characteristics from this common but still unknown species. A diferencia de las especies de interés comercial, la historia de vida de los peces no comerciales es casi desconocida a pesar de su potencial importancia en la estructura y función de la comunidad. Para contribuir al conocimiento de estas especies se estimaron algunas características poblacionales del chupalodo Porcihchty sanalis. La fauna de acompa amiento de la pesquería del camarón en el Golfo de California está constituida por especies poco conocidas y de escaso valor comercial. Las especies de la familia Batrachoididae son frecuentemente utilizadas como animales experimentales, pero poco se sabe de P. analis. De esta manera a partir de la fauna de acompa amiento se recolectaron 1 725 organismos y se determinó la relación talla-peso W=0.000092SL3.0509. Mediante ELEFAN I, se estimó un crecimiento moderado (K=0.5/a o) con una longitud asintótica mayor que la observada reportada anteriormente (L∞
Early Life Hormetic Treatments Decrease Irradiation-Induced Oxidative Damage, Increase Longevity, and Enhance Sexual Performance during Old Age in the Caribbean Fruit Fly
Giancarlo López-Martínez, Daniel A. Hahn
PLOS ONE , 2014, DOI: 10.1371/journal.pone.0088128
Abstract: Early life events can have dramatic consequences on performance later in life. Exposure to stressors at a young age affects development, the rate of aging, risk of disease, and overall lifespan. In spite of this, mild stress exposure early in life can have beneficial effects on performance later in life. These positive effects of mild stress are referred to as physiological conditioning hormesis. In our current study we used anoxia conditioning hormesis as a pretreatment to reduce oxidative stress and improve organismal performance, lifespan, and healthspan of Caribbean fruit flies. We used gamma irradiation to induce mild oxidative damage in a low-dose experiment, and massive oxidative damage in a separate high-dose experiment, in pharate adult fruit flies just prior to adult emergence. Irradiation-induced oxidative stress leads to reduced adult emergence, flight ability, mating performance, and lifespan. We used a hormetic approach, one hour of exposure to anoxia plus irradiation in anoxia, to lower post-irradiation oxidative damage. We have previously shown that this anoxic-conditioning treatment elevates total antioxidant capacity and lowers post-irradiation oxidative damage to lipids and proteins. In this study, conditioned flies had lower mortality rates and longer lifespan compared to those irradiated without hormetic conditioning. As a metric of healthspan, we tracked mating both at a young age (10 d) and old age (30 d). We found that anoxia-conditioned male flies were more competitive at young ages when compared to unconditioned irradiation stressed male flies, and that the positive effects of anoxic conditioning hormesis on mating success were even more pronounced in older males. Our data shows that physiological conditioning hormesis at a young age, not only improves immediate metrics of organismal performance (emergence, flight, mating), but the beneficial effects also carry into old age by reducing late life oxidative damage and improving lifespan and healthspan.
Chemical Characterization of N-Hexane Extract Obtained from Lignocellulose Residual Contained in Agroindustrial Wastes  [PDF]
Jorge Ernesto Solá-Pérez, Hugo Saldarriaga-Nore?a, Mario Murillo-Tovar, Gustavo Ronderos-Lara, Verónica Gisela López-Martínez
Journal of Agricultural Chemistry and Environment (JACEN) , 2018, DOI: 10.4236/jacen.2018.72009
Abstract: The chemical composition of n-hexane extractives from lignocellulose residual contained in different agroindustrial wastes was studied. The n-hexane extract, which accounted for 1.6% of total lignocellulose residual weight, was analysed by 1H-NMR and gas chromatography/mass spectrometry. The most predominant compounds identified were aliphatic hydrocarbons (lineal alkanes, branched alkanes, alkenes). Additionally, terpenes, ketones, fatty alcohols, fatty acids and steroids were also found together in minor amounts. The lipophilic compounds in n-hexane extracts in three lignocellulosic wastes, which is highly valuable information for a more complete industrial utilization of these lignocellulosic materials.
Immigration of Post Larvae of Penaeid Shrimp to Terminos Lagoon, Campeche, México: 2013 Annual Cycle  [PDF]
César Flores-Coto, Daniel Embriz-Alba, Mario Alejandro Gómez-Ponce, Juana López-Martínez, Laura Sanvicente-A?orve
Open Journal of Ecology (OJE) , 2018, DOI: 10.4236/oje.2018.89032
Abstract:
Immigration density magnitude and entry sizes of shrimp postlarvae to Terminos Lagoon were analyzed through sixteen fortnightly sampling from March to November in 2013, in three levels in the deepest channel of the Puerto Real inlet. Trapezium nets were used with 1.5 m length, 50 cm mouth diameter and 505 μm mesh, during each sampling 12 casts of 15 minutes/each were made. It was determined the presence of two species Litopenaeus setiferus and Farfantepenaeus duorarum, with total densities of 41.284 and 37.558 Pls 100 m-3 respectively. The annual cycle of immigration of postlarvae was very similar for both species, with a clear pattern of immigration throughout the year, linked to climatic variation, with the highest densities (88%) during rainy season. There were two periods of maximum density, related to the periods of greatest reproduction of these species. The density variation among cast reflects the presence of at least two and probably more postlarvae banks, located some closer than others to the mouth of the lagoon and with different densities in them. The average sizes of the two species were 7.9 mm total length of L. setiferus and 9.0 mm of F. duorarum. The differences in income sizes of both species seem to indicate the habitat preference of adult populations, L. setiferus occurring in more coastal areas than F. duorarum. Considering the variation in density and sizes throughout each sampling period, it is evident that the larvae on the banks belong to different cohorts and that have coincided in their location in front of the mouth.
Additions to the Pantepui pollen flora (Venezuelan Guayana): the Maguire Collection
López-Martínez, C.,Lara, A.,Rull, V.,Campbell, L.
Collectanea Botanica , 2010,
Abstract: This work is a pollen-morphological study of various plant species from Pantepui (Venezuelan Guayana), a region with high biodiversity and endemism, where global warming is expected to have a high impact. The study consists of a series of morphological descriptions of selected taxa from the Maguire pollen reference slide collection of The New York Botanical Garden (NYBG). The collection was initiated under the supervision of Senior Curator Bassett Maguire to advance systematic, palynological, and medical studies; today it has become also useful for other disciplines such as paleoecology, paleoclimatology or forensic studies. The aim of this pollen-morphological study is to enhance the database of pollen descriptions and illustrations for identification purposes, to be used in the ongoing paleoecological reconstructions and, eventually, in other types of studies using pollen, particularly from the Guayanan tepui summits. Este trabajo es un estudio sobre la morfología polínica de varias especies de plantas de Pantepui (Guayana venezolana), una región con elevada biodiversidad y un alto grado de endemismo, donde se espera un fuerte impacto del calentamiento global. El estudio consiste en una serie de descripciones morfológicas de taxones pertenecientes a la colección Maguire de láminas de referencia del Jardín Botánico de Nueva York (NYBG). La colección fue iniciada bajo la dirección del Curador Jefe Basset Maguire con el objeto de avanzar en estudios de sistemática, palinología y medicina; aunque actualmente también resulta útil en otras disciplinas, como por ejemplo la paleoecología, la paleoclimatología o los estudios forenses. El objetivo de este estudio de morfología polínica es aumentar la base de datos de descripciones e ilustraciones polínicas con propósitos de identificación taxonómica, para ser utilizada en reconstrucciones paleoecológicas y otro tipo de estudios actualmente en desarrollo, en particular en las cimas de los tepuis de Guayana.
Análisis tafonómico de los gasterópodos miocénicos de Cuba. Implicaciones paleobiogeográficas
Rafael A. López-Martínez,Reinaldo Rojas-Consuegra
Minería y Geología , 2008,
Abstract: El léxico estratigráfico cubano establece correlaciones entre las formaciones geológicas miocénicas Paso Real (región occidental), Lagunitas y Los Arabos (región central) y el Miembro Baitiquirí de la Formación San Antonio en la región oriental de Cuba, a partir de estudios micropaleontológicos. Se realizó, por primera vez en Cuba, un análisis tafonómico de los gasterópodos miocénicos pertenecientes a estas formaciones para esclarecer las relaciones paleobiogeográficas entre las mismas. Se logró caracterizar los procesos tafogénicos que afectaron a las entidades registradas, las cuales fueron agrupadas en dos tafosistemas. Los resultados sugieren que la localidad de Baitiquirí, en la región oriental, pertenecía en el Mioceno Inferior a un área paleobiogeográfica distinta, por las diferencias en su contenido paleontológico y en su evolución tafonómica respecto al resto de las localidades estudiadas.
The jellyfish fishery in Mexico  [PDF]
Juana López-Martínez, Javier álvarez-Tello
Agricultural Sciences (AS) , 2013, DOI: 10.4236/as.2013.46A009
Abstract: Jellyfish has been captured in Asia for 1700 years, and it has been considered a delicacy. Since the 70s important jellyfish fisheries have developed in several parts of the world, with catches increasing exponentially, reaching 500,000 tons per year in the mid-nineties. In Mexico, only the cannonball jellyfish Stomolophus meleagris is captured commercially. Most of the capture of this jellyfish species is obtained within the Gulf of California, specifically in the state of Sonora. The total reported capture in 2010 was 16,581 metric t and 14,220 in 2011. With these capture volumes jellyfish was ranked as the third most important fishing resource in the state of Sonora. The fishing season in Sonora is from April to May; a total of 4 or 5 weeks, and the catch per unit effort is around 3 tons by trip. Currently, there are nine jellyfish marketing companies, with about 20 processing plants distributed along the coast of Sonora, primarily in Guaymas, Kino Bay, and Puerto Penasco. Although the process is simple, the large amounts of jellyfish required and the need to optimize production costs make jellyfish processing an intense activity that employs hundreds of people during the fishing season, becoming an alternative employment for the people who depend on the fishing industry.
Spatial distribution and species composition of small pelagic fishes in the Gulf of California
Lanz,Edgar; Nevárez-Martínez,Manuel O; López-Martínez,Juana; Dworak,Juan A;
Revista de Biología Tropical , 2008,
Abstract: traditional regionalization methods in fisheries based on provinces or major fishing areas, includes large and arbitrary grids in which basic statistics or inferences on distribution or abundance are made. we describe a method for regionalization and analysis of fishing activities for small pelagic fisheries in the gulf of california based on spatial patterns of landing and catch data in a geographic information system (gis) environment. a fisheries database from logbooks with spatial attributes from october 2002 to june 2007 was analyzed. landings and catching data were transformed to a weighted region index (wri) by using fuzzy logic operators. the wri revealed fishing action centers characterized by areas with the highest wri values, and a hierarchy for the relative importance of the regions was established. guaymas, desemboque de caborca, isla patos, and bahía san rafael they were the most prominent ones. an analysis of the relative frequency of species composition showed that the pacific sardine had an over 80 % abundance in the midriff islands, and remained as the most important in the upper gulf regions, while in the central part of the gulf, relative abundances of pacific sardine and northern anchovy were more balanced. relative abundance of mackerel was significantly larger around isla patos than in any other place. guaymas had the largest relative composition of northern anchovy and the lowest values for pacific sardine. desemboque de caborca showed the largest homogeneity in species relative composition. it is important to highlight that this results come from in situ data, while the results previously reported come from landing statistics by port. therefore, the present method acknowledges the spatial differences of species by regions, additional to the traditional time series analysis. rev. biol. trop. 56 (2): 575-590. epub 2008 june 30.
Ignimbritas hiperalcalinas del Mioceno medio en Sonora Central: revaluación de la estratigrafía y significado del volcanismo terciario
Vidal-Solano, Jesús R.;Paz-Moreno, Francisco A.;Demant, Alain;López-Martínez, Margarita;
Revista mexicana de ciencias geológicas , 2007,
Abstract: a peculiar volcanic episode represented by peralkaline ignimbrites and rhyolitic domes, has been recognized among the tertiary volcanic sequences of central sonora. field studies, 40ar/39ar geochronology, mineral chemistry and geochemistry (major and trace elements), contribute to establishing the volcanic stratigraphy and the characteristics of these lavas. 40ar/39ar dates give very similar ages of 12 ma, showing that all the peralkaline rocks from central sonora belong to the same volcanic episode. peralkaline rocks have a typical anhydrous mineral association (sanidine+fayalite+ferich, green clinopyroxene), very distinctive from that of the calc-alkaline silicic rocks in the region. these high-silica magmas have relatively high iron, and low alumina contents that classify them as comendites. the ree patterns are characterized by a slight enrichment in lree, a strong negative anomaly in eu, and fiat hree pattern. the low concentrations in ti, p, sr and ba are in accordance with the high degree of differentiation of these liquids. the existence of such a middle miocene peralkaline episode, with a wide geographic extension, constitutes a clear geological marker in the region. the intimate association of these lavas with clastic sedimentary deposits and the eruption, shortly after (11 ma), of differentiated tholeiitic magmas (islandites), show that the middle miocene volcanism was clearly related to extensional tectonism and lithospheric thinning processes which precede the opening of the gulf of california.
Page 1 /613540
Display every page Item


Home
Copyright © 2008-2017 Open Access Library. All rights reserved.