Impacts of Colombia's current irrigation management transfer program

Privatization / Irrigation management / Irrigated farming / Policy / Costs / Economic aspects / Operations / Maintenance / Agricultural production

Landsliding and its multiscale influence on mountainscapes

Landsliding is a complex process that modifies mountainscapes worldwide. Its severe and sometimes long-lasting negative effects contrast with the less-documented positive effects on ecosystems, raising numerous questions about the dual role of landsliding, the feedbacks between biotic and geomorphic processes, and, ultimately, the ecological and evolutionary responses of organisms. We present a conceptual model in which feedbacks between biotic and geomorphic processes, landslides, and ecosystem attributes are hypothesized to drive the dynamics of mountain ecosystems at multiple scales. This model is used to integrate and synthesize a rich, but fragmented, body of literature generated in different disciplines, and to highlight the need for profitable collaborations between biologists and geoscientists. Such efforts should help identify attributes that contribute to the resilience of mountain ecosystems, and also should help in conservation, restoration, and hazard assessment. Given the sensitivity of mountains to land-use and global climate change, these endeavors are both relevant and timel

Taste and Odor Problems in Clinton Lake Reservoir's Drinking Water

This is the published version, made available with the permission of the publisher.This article was published in the Spring 2012 issue of the Journal of Undergraduate Researc

DEFINING PERCEPTIONS OF WATERSHED MANAGEMENT IN A GREAT PLAINS AND IN AN ANDEAN WATERSHED

The goal of this thesis project was to explore the perception groups related to watershed management in a Great Plains and in an Andean Watershed. It is essential for watershed stakeholders to acknowledge that there are different perceptions about watershed management among themselves. The Q methodology is an innovative and dynamic interview method that uses qualitative and quantitative data to interpret participants' perceptions. In Kansas, the stakeholder group displayed three perception groups: hands-on rural residents; detail oriented urban and suburban residents; and pro data collection and conservation of natural functions government official. The Andean watershed also displayed three perception groups: Manizales needs proactive measures to prepare for future landslide events; it was not waters of Manizales, it was nature; and preventing the incrimination of specific institutions. A better understanding of the contrasting perceptions of individuals making up both of these stakeholder groups can substantially improve water resource management

Inhibition causes ceaseless dynamics in networks of excitable nodes

The collective dynamics of a network of excitable nodes changes dramatically when inhibitory nodes are introduced. We consider inhibitory nodes which may be activated just like excitatory nodes but, upon activating, decrease the probability of activation of network neighbors. We show that, although the direct effect of inhibitory nodes is to decrease activity, the collective dynamics becomes self-sustaining. We explain this counterintuitive result by defining and analyzing a "branching function" which may be thought of as an activity-dependent branching ratio. The shape of the branching function implies that for a range of global coupling parameters dynamics are self-sustaining. Within the self-sustaining region of parameter space lies a critical line along which dynamics take the form of avalanches with universal scaling of size and duration, embedded in ceaseless timeseries of activity. Our analyses, confirmed by numerical simulation, suggest that inhibition may play a counterintuitive role in excitable networks.Comment: 11 pages, 6 figure

Propiedades morfológicas y estructurales de recubrimientos nitruro de titanio aluminio producidos por magnetron sputtering tríodo

TixAl1-xN coatings were grown using the triode magnetron sputtering technique varying the bias voltage between -40 V and -150V. The influence of bias voltage on structural and morphological properties was analyzed by means of energy dispersive spectroscopLos recubrimientos TixAl1-xN se cultivaron usando la técnica de pulverización catódica con magnetrón triodo, variando el voltaje de polarización entre -40 V y -150V. La influencia del voltaje de polarización en las propiedades estructurales y morfológica

Methods employed in optical emission spectroscopy analysis: a review

In this work, different methods employed for the analysis of emission spectra are presented -- The proposal is to calculate the excitation temperature (Texc), electronic temperature (Te) and electron density (ne) for several plasma techniques used in the growth of thin films -- Some of these techniques include magnetron sputtering and arc discharges -- Initially, some fundamental physical principles that support the Optical Emission Spectroscopy (OES) technique are described; then, some rules to consider during the spectral analysis to avoid ambiguities are listed -- Finally, some of the more frequently used spectroscopic methods for determining the physical properties of plasma are describe

Estimating the NAIRU for Chile

The purpose of this paper is to obtain a set of estimates of the non-accelerating-inflation rate of unemployment (NAIRU) for Chile. Measuring the NAIRU permits building the unemployment gap, which is a complementary measure of activity and output gap, which is used on a regular basis by central banks as another indicator helping in inflation forecasts and policy decision making. Initially, an estimate is obtained based on a purely statistical method (unobserved components) Later, estimates are conducted for both constant and variable NAIRU based on Phillips curve equations. The different estimates yield similar results, indicating that the most likely point estimate for the current NAIRU stands between 7.4% and 8.3%. However, these figures are contained in a confidence interval ranging from 6.5% to 9.7%, reflecting great uncertainty regarding the exact value of NAIRU.