Numerical simulation of fracture pattern development and implications for fuid flow

Simulations are instrumental to understanding flow through discrete fracture geometric representations that capture the large-scale permeability structure of fractured porous media. The contribution of this thesis is threefold: an efficient finite-element finite-volume discretisation of the advection/diffusion flow equations, a geomechanical fracture propagation algorithm to create fractured rock analogues, and a study of the effect of growth on hydraulic conductivity. We describe an iterative geomechanics-based finite-element model to simulate quasi-static crack propagation in a linear elastic matrix from an initial set of random flaws. The cornerstones are a failure and propagation criterion as well as a geometric kernel for dynamic shape housekeeping and automatic remeshing. Two-dimensional patterns exhibit connectivity, spacing, and density distributions reproducing en echelon crack linkage, tip hooking, and polygonal shrinkage forms. Differential stresses at the boundaries yield fracture curving. A stress field study shows that curvature can be suppressed by layer interaction effects. Our method is appropriate to model layered media where interaction with neighbouring layers does not dominate deformation. Geomechanically generated fracture patterns are the input to single-phase flow simulations through fractures and matrix. Thus, results are applicable to fractured porous media in addition to crystalline rocks. Stress state and deformation history control emergent local fracture apertures. Results depend on the number of initial flaws, their initial random distribution, and the permeability of the matrix. Straightpath fracture pattern simplifications yield a lower effective permeability in comparison to their curved counterparts. Fixed apertures overestimate the conductivity of the rock by up to six orders of magnitude. Local sample percolation effects are representative of the entire model flow behaviour for geomechanical apertures. Effective permeability in fracture dataset subregions are higher than the overall conductivity of the system. The presented methodology captures emerging patterns due to evolving geometric and flow properties essential to the realistic simulation of subsurface processes

Newtonian gravity and resonance on de-Sitter branes

A dS brane on the boundary between two five-dimensional spacetimes is determined. We consider asymmetric scenarios with AdS${}_5$ vacua at each side of the dS brane; and as a result, a resonant mode inside of the spectrum of the gravitational fluctuations is found. We analyze the deviations to the Newton potential generated by the gravitational excitations, finding that, for scenarios with large values of the cosmological constants, the contribution of the resonant mode is exponentially suppressed. However, when one of the vacua is null, the resonant mode belongs to the light states set of the gravitational fluctuations and five-dimensional gravity is recovered on the dS brane.Comment: 6 pages, 2 figure

A Comparison of Traditional and Culturally Sensitive Parent Training of Functional Communication Training

The purpose of the present study was to evaluate the effect of culturally sensitive interventions on parent training. Behavior-analytic services were provided to 3 Latino/Latina families that included children diagnosed with developmental disabilities whose problem behaviors were maintained by social reinforcement. Children were exposed to preference assessments and a functional analysis. Parents then were trained on the implementation of Functional Communication Training (FCT) using English as well as Spanish protocols. Data were collected on the percentage of correct steps completed by the parent as well as levels of child problem behavior. Culturally sensitive intervention does not impact parent training. This study adds to the literature on applied behavior analysis and culturally sensitive interventions

A Framework To Align Strategy, Improvement Performance, And Customer Satisfaction Using An Integration Of Six Sigma And Balanced

This dissertation investigated the development, implementation, and evaluation of a management methodology founded on the alignment among the strategy, performance, and customer to bring value to any organization. A case study/action research in a service organization, called Institution Z, provided the opportunity to assess the effects of the proposed Six Sigma Scorecard (SSS) methodology in the productivity indicators (measured by cycle time, line capacity, and number of errors). The Case study/action research was conducted in three phases: Model and Concepts Design, Data Collection, and Findings. During the research, validity was pursued by using triangulation and theory to help maintain the case under research control. The observation of the SSS methodology in a real organization allowed the researcher to describe the merging process between Balanced Scorecard and Six Sigma methodology and their relationships to each other. The SSS methodology allowed identification of improvement projects that contribute to organizational strategy, implementation of strategies and provide feedback to the top level of management establishing alignment at three organizational levels - corporate, business, and functional. The results of the implementation of the SSS methodology in Institution Z showed a 40% improvement of the cycle time of the auto credit process, a 500% increase in the capacity of the process, and 65% decrease in the number of non-added value activities. During the same period of time, the BSC indicators showed a positive impact, specifically one financial indicator known as Level of Intermediation or GIC grew from 30% to 42% as it was expected by the end of the SSS implementation. The demonstration of the SSS framework in a Case study justifies the need for a combined methodology that aligns strategy, performance improvement and organizational outputs in a feedback loop. More research in this area is needed, especially investigations that include assessment studies where different management approaches are used alone and combined with strategic tools, and investigations that measure the relationship between level of coherence in the three merging points of the SSS and the results reached at the performance of the organization

Community ecology and phylogeography of bird assemblages in arid zones of northern Venezuela: Implications for the conservation of restricted-range birds

Aridlands of northern Venezuela are important from an ornithological perspective because of the occurrence of habitat specialist birds that depend exclusively on desert scrubs and are endemic to this region. Currently, long-term survival of habitat specialists is threatened by ongoing changes in vegetation but the effects of such changes on bird assemblages are unknown. The goal of this study was to characterize bird assemblages found in six arid zones in northern Venezuela at both ecological and genetic levels, and to generate information relevant for conservation planning. The study involved assessments of patterns of avian species richness, abundance, community composition and genetic diversity, as well as specific bird-habitat associations. Through systematic surveys, 96 bird species were recorded throughout the study areas. Even though the six areas support a homogeneous habitat type, species richness, composition, and abundance varied among them. The most abundant birds in all six areas were widespread generalists, and only one of the habitat specialists had high densities in all areas. Species richness was not a good indicator of an area?s conservation value, because the protection of the area with highest number of species does not guarantee the effective conservation of all habitat specialist birds. Vegetation analyses indicated differences in mean values of both floristic and structural vegetation variables among the six study areas but, overall, the six areas had relatively similar vegetation. Habitat specialists differed in their responses to vegetation variables, which may be related to differences in foraging strategies. Even though habitat specialists did not respond strongly to vegetation variables, results of this study suggest that some structural attributes are important for the survival of this particular group of species. Molecular techniques were used to investigate patterns of genetic diversity in three codistributed specialist birds. Multiple analyses indicated geographic structure in the three species, but the extent of geographic structure varied among them as a result of different levels of population isolation during historical times. The assessment of genetic diversity and geographic structure of these three restricted birds showed incongruent patterns, which evidence different evolutionary histories

SWOT analysis of specialised and transport facilities in the logistics infrastructure of Mexico 2013-2018

Mexico obtained best score in geographical aspects, from a geo-strategic comparative study between Mexico and Panama; next step is to identify if the country has a strengthened or weak facilities in terms of transport and logistics, necessary to improve competitiveness with respect to the mentioned items. The objective of this work is to identify, through the SWOT matrix, positive and negative aspects of the nation's logistics infrastructure and, using the confrontation matrix, identify the critical aspects that require design of strategies that will contribute to the improvement of the country's competitiveness. Results show that although nation has logistics infrastructure around the country (including development and construction projects), its biggest disadvantage is the saturation concentrated in the central region, evidencing a low development of these in northern and southern regions of the nation. Finally, improvement strategies for the equitable distribution of logistics facilities by region, according to their specialty, are proposed

Armed conflict characteristics and its effects on firm exit

This paper uses two unique panel data sets to study the causal effect that different characteristics of the armed conflict have over firm exit in Colombia. Using a fixed effects estimation methodology at the plant level and controlling for the possible endogeneity of armed conflict through the use of instrumental variables, we find that the particular armed group that operates in a given region, the level of polarization of the conflict as well as the specific target of the attack impact in a differential manner the probability of firm exit. This poses important implications for policy recommendations and actions in the different regions of the country

Potential influence of blueberry and black raspberry pomace phenolics on inflammatory cytokines in coronary cells

Elevated free fatty acids (FFAs) in obesity are known risk factors associated with chronic inflammatory conditions including cardiovascular inflammation and thus cardiovascular disease (CVD), the leading cause of death in the US. Anthocyanins from berries have the potential to provide protection against inflammation in various tissues; however they are poorly absorbed and undergo major transformations by the microbiome. The work presented in this dissertation involves the development and utilization of an in vitro model to characterize the products of colonic fermentation and absorption of blueberry and black raspberry pomace phenolics, and evaluate the potential efficacy of these products compared to anthocyanin-rich extracts as anti-inflammatory compounds in fatty acid-induced inflammation. A previous study identified myristic and palmitic acids as the most inflammatory, and linoleic acid as least inflammatory. In the first study, a model of colonic fermentation and transport through Caco-2 cells was used to evaluate the changes in phenolic profile of blueberry and black raspberry pomaces. Phenolic acids deriving from anthocyanin degradation were identified as the major products of berry pomace digestion and absorption. The second study involved the use of palmitic acid-stimulated HCAE and HCASM cells to evaluate the anti-inflammatory properties of anthocyanin-rich extracts and phenolic acids produced by microbiota fermentation and transport across Caco-2 monolayers using the prevention and intervention approaches. Protein and gene expression of inflammation markers demonstrate that phenolic acids derived from fermentation and absorption of both blueberry and black raspberry pomaces were equally or more effective than anthocyanin-rich extracts in modulating the inflammatory response through a proposed effect on NF-κB transcription, especially when used in the prevention approach. This suggests that phenolic acids may be responsible for some of the beneficial effects of blueberries and black raspberries. We have also demonstrated that berry pomaces, could be utilized in foods, providing anthocyanins and phenolic acids that may prevent inflammation in cardiovascular cells

Firm exit and armed conflict in Colombia

This paper uses two unique panel data sets to study the causal effect that armed conflict has over entrepreneurial activity in Colombia. Using a fixed effect estimation methodology at the plant level and controlling for the possible endogeneity of armed conflict through the use of instrumental variables, we find that a one standard deviation increase in the number of guerrilla and paramilitary attacks in a municipality increases the probability of plant exit in 5.2 percentage points or 0.26 standard deviations. This effect is stronger for younger manufacturing plants, with a smaller number of workers and low levels of capital