Anuario Estadistico de Pesca 1982

This document is in Spanish. La Secretaría de Pesca, a través de la Direcci6n General de Informática, Estadística y Documentaci6n,presenta el ANUARIO ESTADISTICO correspondiente a 1982, con la informaci6n cuantitativa más relevante de las diversas fases que confo·rman la actividad pesquera nacional y la de los sectores que en ella participan, así como los principales indicadores pesqueros internacionales. El Fresente documento está integrado por trece capítulos: I. Capturas, II. Permisos, III. Embarcaciones, IV. Artes y EquiI-' os de Pesca, V. Industrialización, VI. Origen y Destino de loo productos Pesqueros, VII. Comercialización, VIII. Consumo, IX. Población, X. Capacitación, XI. Financiamiento, XII. Información Internacional de Pesca, XIII. Cuenta Nacional pesqu~ ra. Al final del documento se incluyen dos anexos, el Frimero presenta el índice detallado de cuadros y el segundo el glosario de términos. Catch statistics for Mexican waters 1982. (PDF has 482 pages.)

Temperature-and pH-Sensitive Nanohydrogels of Poly(N-Isopropylacrylamide) for Food Packaging Applications: Modelling the Swelling-Collapse Behaviour

Temperature-sensitive poly(N-isopropylacrylamide) (PNIPA) nanohydrogels were synthesized by nanoemulsion polymerization in water-in-oil systems. Several cross-linking degrees and the incorporation of acrylic acid as comonomer at different concentrations were tested to produce nanohydrogels with a wide range of properties. The physicochemical properties of PNIPA nanohydrogels, and their relationship with the swelling-collapse behaviour, were studied to evaluate the suitability of PNIPA nanoparticles as smart delivery systems (for active packaging). The swelling-collapse transition was analyzed by the change in the optical properties of PNIPA nanohydrogels using ultraviolet-visible spectroscopy. The thermodynamic parameters associated with the nanohydrogels collapse were calculated using a mathematical approach based on the van't Hoff analysis, assuming a two-state equilibrium (swollen to collapsed). A mathematical model is proposed to predict both the thermally induced collapse, and the collapse induced by the simultaneous action of two factors (temperature and pH, or temperature and organic solvent concentration). Finally, van't Hoff analysis was compared with differential scanning calorimetry. The results obtained allow us to solve the problem of determining the molecular weight of the structural repeating unit in cross-linked NIPA polymers, which, as we show, can be estimated from the ratio of the molar heat capacity (obtained from the van't Hoff analysis) to the specific heat capacity (obtained from calorimetric measurements).

Variación temporal del ADNmt en poblaciones de la cornisa cantábrica. Contribución del AND antiguo

333 p.

Kinetic Study Of The Rayleigh-Benard Flows

The present paper employs the direct simulation Monte Carlo (DSMC) method to study the Rayleigh-Benard flows, where the temperature ratio of the upper to lower plate is fixed to 0.1. For a Knudsen number (Kn) of 0.01, as the Rayleigh number (Ra) increases, the flow changes from the thermal conductive state to the convective state at about Ra=1700, and the calculated relation of heat flux through the lower plate versus Ra is in good agreement with classical experimental and theoretical results. For Kn=0.05, the thermal conductive state remains stable, and the increase of Ra cannot trigger thermal instability.