Assessment of the fishing effort level in the shrimp fisheries of the central and southern Gulf of California

In view of the concern caused by the declining trend in the annual shrimp yield in the Central Gulf of California, an attempt was made to analyze the fishing effort level exerted upon the shrimp stocks of the blue (Farfantepenaeus stylirostris) and the brown shrimp (F. californiensis) from 1980 to 1991. For this purpose, both Schaefer and Fox production models were applied. The results from these analyses revealed an economic overexploitation condition, and suggested an imperative need to implement as a regulatory measure, the reduction of the catch per unit of effort level (CPUE) to keep the fishery within acceptable bioeconomic margins of a maximum sustainable yield (Ys). This can only be achieved through the adjustment of the fleet size from 481 vessels down to 250 or 275

Assessment of the fishing effort level in the shrimp fisheries of the central and southern Gulf of California

In view of the concern caused by the declining trend in the annual shrimp yield in the Central Gulf of California, an attempt was made to analyze the fishing effort level exerted upon the shrimp stocks of the blue (Farfantepenaeus stylirostris) and the brown shrimp (F. californiensis) from 1980 to 1991. For this purpose, both Schaefer and Fox production models were applied. The results from these analyses revealed an economic overexploitation condition, and suggested an imperative need to implement as a regulatory measure, the reduction of the catch per unit of effort level (CPUE) to keep the fishery within acceptable bioeconomic margins of a maximum sustainable yield (Ys). This can only be achieved through the adjustment of the fleet size from 481 vessels down to 250 or 275.Shrimp fisheries, Fishing effort, Catch/ effort, California Gulf, Farfantepenaeus stylirostris, Farfantepenaeus californiensis

La planificación aplicada del sector agropecuario en el departamento de Cundinamarca.

Maestría en CienciasMaestrí

Numerical analysis of gas-solidsflow hydrodynamics and heat transfer in two outlet configurationindustrial riser using mesoscale theory to predict the interfacialdrag

Se analizan numéricamente dos configuraciones de un riser del proceso FCC variando la disposición de la salida superior, usando un modelo CFD en 2 D que incluye el Modelo de los Dos Fluidos (TMF), la Teoría Cinética del Flujo Granular (KTGF) y como modelo de arrastre el modelo de la Minimización de la Energía Multi-Escala (EMMS). El modelo se resuelve a través del programa ANSYS Fluent® 14.5 solucionando las ecuaciones de balance de masa, momentum y energía; y ecuaciones constitutivas para calcular la interacción entre las fases, la fase sólida con las paredes, y las propiedades de la fase granular. El modelo propuesto en este trabajo predice adecuadamente el comportamiento del flujo gas-sólido, prediciendo diferentes patrones de flujo en las coordenadas axial y radial del riser; así como zonas concentradas y diluidas de sólidos en la parte baja y alta del riser, respectivamente. Las fluctuaciones en la concentración y las velocidades de los sólidos tanto radial como axialmente que se observan son producto del alto grado de mezclado radial que se acentúa cerca de las paredes del riser debido al arrastre considerado por el modelo utilizado. Por otro lado se observa una rápida estabilización térmica radial y axial alcanzando en poco tiempo el estado estacionario. Los perfiles obtenidos en las dos configuraciones analizadas son muy similares, lo que motiva a que en trabajos futuros se analicen otras configuraciones de salida del riser que permitan mejorar los patrones de concentración y velocidades de los sólidos.In the FCC process two configurations riser are numerically analyzed varying the upper outlet orientation using a 2 D CFD model which includes the Two Fluid Model (TFM), Kinetic Theory of Granular Flow (KTGF), and Energy Minimization Multi-Scale (EMMS) theory as drag model. This model is solved using the ANSYS Fluent® 14.5 software, solving the governing equations of mass, momentum, and energy balance; and the constitutive equations to calculate interfacial interaction, wall-solid phase interaction, and granular phase properties. The model proposed in this work properly predicts the gas-solid flow behavior, predicting different solid flow patterns in radial and axial riser directions, as well as concentrated and diluted zones at riser's top and bottom respectively. The radial and axial solids concentration and velocities profiles fluctuations observed are produced by the high radial solid mix which is higher near the riser walls due to drag force considered by the model used. On the other hand, a rapid radial and axial thermal stabilization is observed reaching the steady state rapidly. The profiles obtained from riser configurations analyzed are very similar, so in future works other riser outlets configurations will be analyzed to try to improve the solid concentration and velocity profiles.Peer Reviewe

Candida albicans Inhibits Pseudomonas aeruginosa Virulence through Suppression of Pyochelin and Pyoverdine Biosynthesis.

Bacterial-fungal interactions have important physiologic and medical ramifications, but the mechanisms of these interactions are poorly understood. The gut is host to trillions of microorganisms, and bacterial-fungal interactions are likely to be important. Using a neutropenic mouse model of microbial gastrointestinal colonization and dissemination, we show that the fungus Candida albicans inhibits the virulence of the bacterium Pseudomonas aeruginosa by inhibiting P. aeruginosa pyochelin and pyoverdine gene expression, which plays a critical role in iron acquisition and virulence. Accordingly, deletion of both P. aeruginosa pyochelin and pyoverdine genes attenuates P. aeruginosa virulence. Heat-killed C. albicans has no effect on P. aeruginosa, whereas C. albicans secreted proteins directly suppress P. aeruginosa pyoverdine and pyochelin expression and inhibit P. aeruginosa virulence in mice. Interestingly, suppression or deletion of pyochelin and pyoverdine genes has no effect on P. aeruginosa's ability to colonize the GI tract but does decrease P. aeruginosa's cytotoxic effect on cultured colonocytes. Finally, oral iron supplementation restores P. aeruginosa virulence in P. aeruginosa and C. albicans colonized mice. Together, our findings provide insight into how a bacterial-fungal interaction can modulate bacterial virulence in the intestine. Previously described bacterial-fungal antagonistic interactions have focused on growth inhibition or colonization inhibition/modulation, yet here we describe a novel observation of fungal-inhibition of bacterial effectors critical for virulence but not important for colonization. These findings validate the use of a mammalian model system to explore the complexities of polymicrobial, polykingdom infections in order to identify new therapeutic targets for preventing microbial disease

Unmasking the tail of the cosmic ray spectrum

A re-examination of the energy cosmic ray spectrum above $10^{20}$ eV is presented. The overall data-base provides evidence, albeit still statistically limited, that non-nucleon primaries could be present at the end of the spectrum. In particular, the possible appearance of superheavy nuclei (seldom discussed in the literature) is analysed in detail.Comment: To appear in Phys. Lett. B with the title ``Possible explanation for the tail of the cosmic ray spectrum'

Variación de las comunidades microbianas en función de las diferentes fases térmicas en el proceso de compostaje del alperujo

En San Juan, el cultivo de olivo es uno de los de mayor importancia económica para la provincia. Del total de aceituna cosechada por campaña el 60% es destinada a la elaboración de aceita de oliva. De la extracción de aceite de oliva, se obtiene un residuo semisólido denominado, alperujo. Este residuo está constituido por los restos de la aceituna, que contiene elevado contenido de compuestos fenólicos y grasas, que limitan su utilización directa como enmienda de suelos cultivados. El compostaje, es una alternativa para reutilizar y disminuir la toxicidad de estos residuos orgánicos.EEA San JuanFil: Paroldi, H.E. Universidad Nacional de San Juan. Facultad de Ingeniería; ArgentinaFil: Medina, E.M. Universidad Nacional de San Juan. Facultad de Ingeniería; ArgentinaFil: Rodriguez, L.A. Universidad Nacional de San Juan. Facultad de Ingeniería; ArgentinaFil: Monetta, Pablo Miguel. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria San Juan; Argentin