Irrigation and water resources in Latin America and the Caribbean: challenges and strategies

Latin America and the Caribbean are relatively well endowed with water resources. However, population growth and rapid urbanization are putting considerable pressure on water available for irrigation. Local and regional water scarcity problems are exacerbated by severe water quality problems; and wastewater is frequently used for irrigation. Moreover, prospects for new investments into irrigation development appear limited. This paper examines the factors underlying irrigation development in Latin America and the Caribbean, reviews the water supply situation, and describes trends in water demand and irrigated agriculture. The overall water management in the region is assessed, and recent trends in investments in the water sector, with a focus on large-scale irrigation systems, are analyzed. The paper concludes that in this context of accelerating demand and declining irrigation investments, new water development is not the primary solution to water resource challenges in the region. Much greater attention is needed on water policy and management reform to improve the efficiency and equity of irrigation and water supply systems.Water resources development Caribbean Area., Water-supply., Water use Management., Irrigation farming.,

Numerical Modeling Of Hohlraum Radiation Conditions: Spatial And Spectral Variations Due To Sample Position, Beam Pointing, And Hohlraum Geometry

View-factor simulations are presented of the spatially varying radiation conditions inside double-ended gold Hohlraums and single-ended gold Hohlraums (\u27\u27 halfraums \u27\u27) used in inertial confinement fusion and high-energy density physics experiments [J. Lindl, Phys. Plasmas 11, 339 (2004); M. D. Rosen, Phys. Plasmas 3, 1803 (1996)]. It is shown that in many circumstances, the common assumption that the Hohlraum \u27\u27 drive \u27\u27 can be characterized by a single temperature is too simplistic. Specifically, the radiation conditions seen by an experimental package can differ significantly from the wall reemission measured through diagnostic holes or laser entrance holes (LEHs) by absolutely calibrated detectors. Furthermore, even in situations where the radiation temperature is roughly the same for diagnostics and experimental packages, or for packages at different locations, the spectral energy distributions can vary significantly, due to the differing fractions of reemitting wall, laser hot spots, and LEHs seen from different locations. We find that the spatial variation of temperature and especially the differences between what diagnostics looking in the LEH measure versus the radiation temperature on wall-mounted experimental packages are generally greater for double-ended Hohlraums than for halfraums. View-factor simulations can also be used to explore experimental variables (halfraum length and geometry, sample position, and beam pointing) that can be adjusted in order to, for example, maximize the radiation flux onto a sample, or other package. In this vein, simulations of Hohlraums and halfraums with LEH shields are also presented. (c) 2005 American Institute of Physics

2020 Global food outlook

This report shows just how, and how much, certain policy decisions and social changes will affect the world's future food security. It projects the likely food situation in 2020 if the world continues on more or less its present course, and it then shows how alternative choices could produce a different future. Even rather small changes in agricultural and development policies and investments, it turns out, can have wide-reaching effects on the number of poor and undernourished people around the world. A world of less poverty, greater food security, and a healthier environment is possible, but it will not come about without explicit policy steps in that direction. 2020 Global Food Outlook is the latest in a series of world food projections based on a model developed at IFPRI beginning in 1992.The model has been updated and expanded periodically since then as a way of painting an ever-clearer picture of the global food situation in 2020.

The National Ignition Facility Project

The mission of the National Ignition Facility is to achieve ignition and gain in ICF targets in the laboratory. The facility will be used for defense applications such as weapons physics and weapons effect testing, and for civilian applications such as fusion energy development and fundamental studies of matter at high temperatures and densities. This paper reviews the design, schedule and costs associated with the construction project

Misplaced Inadequacies: A Comparative Case Study of Three Students Struggling to Learn to Read

Thesis advisor: David ScanlonChanges in policy and practice that originated with the 2004 Reauthorization of the Individuals with Disabilities Education Act ([IDEA], US Department of Education) created systems that exposed students to earlier and more consistent research-based intervention (Fuchs & Vaughn, 2012) thereby reducing the rate and increasing the mean age of students diagnosed with learning disabilities. Despite these documented positive outcomes, research has identified 2 -5 % of students who continue to demonstrate an “inadequate response” to evidence-based instruction that has been largely effective for their peers (Greulich et al., 2014). Little research has traced the educational histories of “inadequate responders,” and no known case studies have included children’s perspectives together with those of their parents and teachers. There is also a dearth of special education literature that is situated in private, faith-based schools where students function without all of the protections and structures of IDEA (Russo et. al., 2011; Scanlan, 2009a). This dissertation was an exploratory, comparative case study (Yin, 2014) of three third grade boys who were identified by their Catholic school staff as having demonstrated an inadequate response to intervention in reading. Each student was observed in a combination of his general education classroom and reading intervention periods, and interviews were conducted with the students and their parents and teachers. The learners’ Individualized Education Programs (IEPs), test reports, and cumulative records were also analyzed. Findings indicated that the students’ identification as inadequate responders did not accurately reflect their early reading experiences in which their instruction did not align with evidenced-based practices for students with learning disabilities (Ehri, Nunes, Stahl, & Willows, 2001). The students shared the deep emotional impact of past school-related events, and demonstrated patterns of sadness, anxiety, and avoidance during reading instruction. Parents and educators expressed their dedication to the students’ achievement as well as their frustration with the lack of comprehensive on-site academic systems of support within the boys’ schools. Implications for creating evidenced-based systems of intervention that honor and take into account the strengths and emotional-needs of students struggling to read are discussed.Thesis (PhD) — Boston College, 2018.Submitted to: Boston College. Lynch School of Education.Discipline: Teacher Education, Special Education, Curriculum and Instruction

Toward Meta-level Control of Autonomous Agents

AbstractMetareasoning is an important capability for autonomous systems, particularly for those being deployed on long duration missions. An agent with increased self-observation and the ability to control itself in response to changing environments will be more capable in achieving its goals. This is essential for long-duration missions where system designers will not be able to, theoretically or practically, predict all possible problems that the agent may encounter. In this paper we describe preliminary work that integrates the metacognitive architecture MIDCA with an autonomous TREX agent, creating a more self-observable and adaptive agent