Results 1 - 10 of 4738
Results 1 - 10 of 4738. Search took: 0.031 seconds
|Sort by: date | relevance|
[en] In 1977, the Methodist Hospital of Lubbock, Texas, sold a 14 year old Picker C-3000 therapy unit to Mexican Centro de Juarez, instead of taking up the Picker option of dismantling, removal and safe storage. The device was never used for research or treatment, and the resulting accident after its dismantling and dispersion of the parts by unknown persons in November 1983 is described in outline. (U.K.)
[en] An overview is presented of the Mexican petroleum sector. The sector is largely controlled by the state company PEMEX and is not completely open to foreign participation and supply, however the trend towards privatization and open competition, combined with the drive for competitiveness of PEMEX operations in particular, is creating market opportunities for foreign suppliers of petroleum equipment and services. Detailed profiles are provided of 50 Mexican companies and their primary products and services, specific areas of expertise, client base, international experience, interest in Canada, other relevant information, and a contact person. A less detailed list is also provided of additional Mexican contacts, petroleum industry associations and chambers of commerce
[en] The composition and abundance of phytoplankton community, and its relation to physical and chemical factors was evaluated in the fluvial-lagoon systems Pom-Atasta (PA) and Palizada del Este (PE), in February, 2011. Water samples were collected in ten sampling sites in each lagoon, with a van Dorn bottle at the surface and in the middle of the water column to measure temperature, salinity, dissolved oxygen, inorganic nutrients, chlorophyll a and the composition and abundance of phytoplankton. In order to describe the behavior of phytoplankton it was calculated species abundance, Shannon-Wiener diversity and Pielou equitability indices were used, and to analyze the relationship between the abundance of phytoplankton species and environmental variables, a canonical correspondence analysis (CCA) was applied. The results showed that PE was the lagoon that presented a great biodiversity with 348 identified taxa, maximum abundance values (269 X 103 cells L-1), H' (3.2) and J' (0.95). Cylindrotheca closterium was the most abundant species in both systems, observing the highest abundance (52.5 X 103 cells L-1) in PA, forming incipient toxic algal blooms. It should be noted that salinity was the most influential environmental variable in the composition and abundance of phytoplankton.
[en] Cyanobacteria inhabit hypersaline, marine and freshwater environments. Some toxic and non-toxic species can form harmful blooms. The aim of this study was to identify potentially harmful cyanobacterial species in the oyster banks of Terminos Lagoon, the southeastern Gulf of Mexico. Six sample sites (up to 2-m depth) were monitored monthly from August 2012 to September 2013. Water temperature, salinity, pH, dissolved oxygen saturation (% DO), inorganic nutrients and abundance of cyanobacteria were determined. Temperature and salinity were characterized by marked seasonal differences (26.8 to 30.6 Celsius degrade and 6.1 to 19.5, respectively). The pH values (ranging from 7.1 to 8.4) and the % DO (88.4 to 118.2 %) suggest a predominance of photosynthetic activity in the windy season (October-February). Elevated nutrient contents are associated with the period of increased river discharge, determined by water circulation and biogeochemical processes. Fourteen taxa were identified, of which Anabaena sp., Merismopedia sp., Oscillatoria sp. and Cylindrospermopsis cuspis produced blooms. Cyanobacterial abundances were on the order of magnitude of 106 cells L-1 in October 2012 at stations S1-S6, with an average value of 3.2x105 cells L-1 and a range of 2000 to 3.1x106 cells L-1 throughout the study period; however, they showed a remarkable absence during the windy season (October to January). Anabaena sp. and C. cuspis reached abundances of 1.9x106 and 1.3x106 cells L1, respectively. The latter caused the temporary closure of oyster Crassostrea virginica harvesting for 15 days in October 2012.
[en] The content and composition of the fatty acids (F As) and astaxanthin (AST) in the edible forms of crayfish: the whole animal of Cambarellus (C.) montezumae, and the tail meat (TM) of Procambarus (M.) bouvieri were determined by GC and HPLC. The exoskeleton (EXK) of P. (M.) bouvieri was also studied. Unsaturated FAs, and mostly oleic acid (C18:1 n-9), were predominant in both edible forms. The contents of the polyunsaturated eicosapentaenoic (C20:5 n-3, EPA), arachidonic (C20:4 n-6, ARA) and docosahexaenoic acid (C22:6 n-3, DHA), were higher in the TM of P. (M.) bouvieri than in the complete C. (C.) montezumae (p<0.05). Total carotenoids ranged between 2.31 ± 0.33 μg·g−1 and 66.3 ± 3.91 μg·g−1, and were composed mainly of AST (>79.50%). AST esters were enriched with saturated FAs in C. (C.) montezumae and with PUFAs in EXK of P. (M.) bouvieri. We conclude that both C. (C.) montezumae and the TM of P. (M.) bouvieri are traditional foods rich in n-3 PUFAs and C. (C.) montezumae in AST. The EXK of P. (M.) bouvieri is a rich potential source of AST, n-3 PUFAs, and the combination AST-DHA.
[es]Se determinó por GC y HPLC el contenido y composición de ácidos grasos (AGs) y astaxantina (AST), en dos formas comestibles de acocil: el animal completo de Cambarellus (C.) montezumae, y el músculo de la cola (MC) de Procambarus (M.) bouvieri. Adicionalmente, se estudió el exosqueleto (EXK) de P. (M.) bouvieri. En ambas formas comestibles predominaron los AGs insaturados. Los contenidos de ácido eicosapentaenoico (C20:5 n-3, EPA), araquidónico (C20:4 n-6, ARA) y docosahexaenoico (C22: 6 n-3, DHA), fueron mayores en el MC que en C. (C) montezumae (p<0,05). Los carotenoides totales oscilaron de 2.3 ± 0.3 μg·g−1 a 66.3 ± 3.9 μg·g−1, con predominancia de AST (>79.50%). Los ésteres de AST en C. (C.) montezumae fueron enriquecidos con AGs saturados mientras que los del EXK de P. (M.) bouvieri con AGs poliinsaturados. Se concluyó que tanto C. (C.) montezumae como el MC de P. (M.) bouvieri, son alimentos tradicionales ricos en PUFAs n-3, y C. (C.) montezumae en AST. El EXK de P.(M.) bouvieri abunda en AST, PUFAs n-3, y en la combinación AST-DHA