Geomechanical Behavior of Bio-Cemented Sand for Foundation Works

Bio-cementation is an innovative green technology that complements existing ground improvement techniques, but it is yet to be proven for large-scale foundation works. Previously attention has been focused on strategies to inject the bacteria and nutrients to produce the cement in the ground. This study looks at the performance of geomechanical response when the bacteria and nutrients are mixed in sand, an approach that is used in producing cemented soil columns. To explore the mechanical response of bio-cemented soil, results from unconfined compressive strength (UCS) tests and triaxial tests have been analyzed to understand the effects of bio-cementation for sand in contrast to alternative cement, gypsum. The stiffness has also been monitored using bender element techniques in triaxial cell. Both the shear wave signals during the cementation phase and the shearing phase were recorded using this technique. The results show that for a given amount of cement, higher resistances are measured for the bio-cemented samples compared to gypsum. The mixing process is shown to produce homogeneous bio-cemented samples with higher strength and stiffness than the technique of flushing or injection commonly used, provided the amount of calcite is less than 4%. The results show that the bio-cement produces similar mechanical behavior to other artificially cemented sands

Avalanche multiplication and breakdown in AlxGa1-xAs (x < 0-9)

Measurements carried out on thick Al/sub x/Ga/sub 1-x/As (x 0.63

La influencia de la ideología en la política turística española y sus enfoques

Este artículo pretende determinar el enfoque de las políticas turísticas españolas en la etapa democrática y establecer la orientación ideológica de dichas políticas. En cuanto a la metodología, se ha empleado un análisis de contenido para determinar el enfoque de las políticas turísticas; y un Método Delphi para determinar su orientación ideológica. Los resultados del análisis de contenido muestran que los dis‑tintos planes de turismo cuentan con enfoques diferenciales. Por su parte, los resultados del Método Delphi muestran los diferentes enfoques ideológicos de los planes de turismo, y, en segundo lugar, los expertos identifican relaciones entre conceptos de política turística y su orientación ideológica. Las principales conclu‑siones son que existen diferencias en el enfoque de las políticas turísticas, pero igualmente, que existen una serie de contenidos comunes en las políticas de turismo de España. Finalmente, esta investigación no puede concluir que exista una relación entre ideología y política turística.This article seeks to determine the approach of the Spanish tourism policy in the democratic period and to establish the ideological orientation of the policies. In reference to the methodology, a content analysis has been utilised to determine the approach of the tourism policies; and a Delphi Method has been used to determine the ideological orientation. The results from the content analysis show how the different tourism plans have differential approaches. In addition, the results from the Delphi Method show the differ‑ent ideological orientations of the tourism plans, and, secondly, the experts identified links between tourism policy concepts and its ideological orientation. The main conclusions are that, there exist differences in the approach of the tourism policies, but at the same time, there exist a series of common contents in the Span‑ish tourism policies. Finally, this research cannot conclude that a link between ideology and tourism policy may exist

A Rapid and Reliable Method of Counting Neurons and Other Cells in Brain Tissue: A Comparison of Flow Cytometry and Manual Counting Methods

It is of critical importance to understand the numbers and distributions of neurons and non-neurons in the cerebral cortex because cell numbers are reduced with normal aging and by diseases of the CNS. The isotropic fractionator method provides a faster way of estimating numbers of total cells and neurons in whole brains and dissected brain parts. Several comparative studies have illustrated the accuracy and utility of the isotropic fractionator method, yet it is a relatively new methodology, and there is opportunity to adjust procedures to optimize its efficiency and minimize error. In the present study, we use 142 samples from a dissected baboon cortical hemisphere to evaluate if isotropic fractionator counts using a Neubauer counting chamber and fluorescence microscopy could be accurately reproduced using flow cytometry methods. We find greater repeatability in flow cytometry counts, and no evidence of constant or proportional bias when comparing microscopy to flow cytometry counts. We conclude that cell number estimation using a flow cytometer is more efficient and more precise than comparable counts using a Neubauer chamber on a fluorescence microscope. This method for higher throughput, precise estimation of cell numbers has the potential to rapidly advance research in post-mortem human brains and vastly improve our understanding of cortical and subcortical structures in normal, injured, aged, and diseased brains

Modeling Caribbean Tourism Demand: An Augmented Gravity Approach

This study uses a gravity framework to model tourism demand for the Caribbean. The basic model is augmented by Linder’s hypothesis—tourist flows are partly determined by the similarity in preferences between the destination and source markets—and climate distance, which measures the gap between climate conditions in origin and destination countries. The results indicate that traditional gravity variables are significant in explaining demand for the region. Habit persistence has the largest impact on demand, a result which holds promise for regional policymakers. Evidence is also unearthed that similarity in preferences between the region and its source markets, and climate distance are important demand determinants

Modeling Caribbean Tourism Demand: An Augmented Gravity Approach

This study uses a gravity framework to model tourism demand for the Caribbean. The basic model is augmented by Linder’s hypothesis—tourist flows are partly determined by the similarity in preferences between the destination and source markets—and climate distance, which measures the gap between climate conditions in origin and destination countries. The results indicate that traditional gravity variables are significant in explaining demand for the region. Habit persistence has the largest impact on demand, a result which holds promise for regional policymakers. Evidence is also unearthed that similarity in preferences between the region and its source markets, and climate distance are important demand determinants

Modeling Caribbean Tourism Demand: An Augmented Gravity Approach

This study uses a gravity framework to model tourism demand for the Caribbean. The basic model is augmented by Linder’s hypothesis—tourist flows are partly determined by the similarity in preferences between the destination and source markets—and climate distance, which measures the gap between climate conditions in origin and destination countries. The results indicate that traditional gravity variables are significant in explaining demand for the region. Habit persistence has the largest impact on demand, a result which holds promise for regional policymakers. Evidence is also unearthed that similarity in preferences between the region and its source markets, and climate distance are important demand determinants