Fast Rendering of Forest Ecosystems with Dynamic Global Illumination

Real-time rendering of large-scale, forest ecosystems remains a challenging problem, in that important global illumination effects, such as leaf transparency and inter-object light scattering, are difficult to capture, given tight timing constraints and scenes that typically contain hundreds of millions of primitives. We propose a new lighting model, adapted from a model previously used to light convective clouds and other participating media, together with GPU ray tracing, in order to achieve these global illumination effects while maintaining near real-time performance. The lighting model is based on a lattice-Boltzmann method in which reflectance, transmittance, and absorption parameters are taken from measurements of real plants. The lighting model is solved as a preprocessing step, requires only seconds on a single GPU, and allows dynamic lighting changes at run-time. The ray tracing engine, which runs on one or multiple GPUs, combines multiple acceleration structures to achieve near real-time performance for large, complex scenes. Both the preprocessing step and the ray tracing engine make extensive use of NVIDIA\u27s Compute Unified Device Architecture (CUDA)

The Public Resource Management Game

Use of public resources for private economic gain is a longstanding, contested political issue. Public resources generate benefits beyond commodity uses, including recreation, environmental and ecological conservation and preservation, and existence and aesthetic values. We analyze this problem using a dynamic resource use game. Low use fees let commodity users capture more of the marginal benefit from private use. This increases the incentive to comply with government regulations. Optimal contracts therefore include public use fees that are lower than private rates. The optimal policy also includes random monitoring to prevent strategic learning and cheating on the use agreements and to avoid wasteful efforts to disguise noncompliant behavior. An optimal policy also includes a penalty for cheating beyond terminating the use contract. This penalty must be large enough that the commodity user who would gain the most from noncompliance experiences a negative expected net return.Renewable resources, public resources policy, optimal contracts

Recovery for Accidental Injuries Under the Virginia Workmen\u27s Compensation Act

The Virginia Workmen\u27s Compensation Act, first enacted in 1918, generally provides for case benefits and medical care to individuals injured in employment-related accidents. While the Act is neither tort law nor social insurance, it contains elements of both. As social legislation, the Act plays an important role in protecting citizens from loss of wages and provides an important supplement to protection available from the federal Old Age, Survivors\u27 Disability and Health Insurance Program, unemployment compensation and private health and accident insurance plans. In 1979, more than 43,000 Virginia employees filed claims under the Act. Unlike other social insurance programs, however, workmen\u27s compensation is funded by neither the employee nor the state. For a qualifying injury, death or disease, liability is borne by the employer and, presumably, passed on to the consumer

Factores que inciden en el uso académico de las TIC en la básica primaria

Maestría en Educación - Modalidad VirtualThe present research work determines the factors that affect the academic use of ICT in the primary level of education; it was worked under a mixed explanatory descriptive approach. A sample was selected, represented by 142 students from the third 3rd to the 5th grade of the basic elementary school of Flowers Hill Bilingual School, annexed Central Baptist School La Esperanza and Escuela Mision Cristiana. The information was collected through a questionnaire applied to 142 students, a focus group for 3 teaching directors, direct observation in the classroom and documentary review of the Institutional Educational Project. The results made it possible to show that among the most relevant factors that affect the academic use of ICTs are the lack of pedagogical teacher training in the use of ICT, the teacher's attitude towards the use of technology in teaching, lack of articulation among the actors of education as teaching managers, teachers and students, lack of an institutional culture around ICT, and the lack of institutional commitment to monitoring the academic use of ICT. Similarly, it was found that all participants recognize the benefits of ICT, especially students; however, it is necessary to strengthen the training and support of higher authorities. It was concluded that the incorporation of ICT to the teaching - learning process with the guidance of the teacher, motivates students to learn and allows teachers to include innovative teaching strategies in the classroomEl presente de trabajo de investigación determina los factores que inciden en el uso académico de las TIC en el nivel educativo de la básica primaria, se trabajó bajo un enfoque mixto de tipo descriptivo explicativo. Fue seleccionada una muestra representada por 142 estudiantes de tercer 3° a quinto 5° grado de la básica primaria de la Institución Educativa Flowers Hill Bilingual School sedes Escuela Bautista Central La Esperanza y Escuela Misión Cristiana. La recogida de la información se realizó mediante un cuestionario aplicado a 142 estudiantes, un grupo focal dirigido a 3 directivos docentes, observación directa en el aula de clases y revisión documental del Proyecto Educativo Institucional. Los resultados permitieron evidenciar que entre los factores más relevantes que inciden en el uso académico de las TIC se encuentran falta de formación pedagógica de docentes en el uso de TIC, la actitud del docente hacia el uso de la tecnología en la enseñanza, falta de articulación entre los actores de la educación como directivos docentes, docentes y estudiantes, falta de una cultura institucional alrededor de las TIC, y la falta de compromiso institucional al seguimiento del uso académico de las TIC. De igual manera, se encontró como resultado que todos los participantes reconocen los beneficios de las TIC, especialmente los estudiantes, sin embargo, se necesita reforzar la capacitación y el apoyo de autoridades superiores. Se concluyó que la incorporación de las TIC al proceso de enseñanza - aprendizaje con la orientación del docente, motiva a los estudiantes por aprender y permite a los docentes incluir estrategias didácticas innovadoras en el aula de clase

AMORD: A Deductive Procedure System

This research was conducted at the Artificial Intelligence Laboratory of the Massachusetts Institute of Technology. Support for the Laboratory's artificial intelligence research is provided in part by the Advanced Research Projects Agency of the Department of Defense under Office of Naval Research contract number N00014-75-C-0643.We have implemented an interpreter for a rule-based system, AMORD, based on a non-chronological control structure and a system of automatically maintained data-dependencies. The purpose of this paper is tutorial. We wish to illustrate: (1) The discipline of explicit control and dependencies, (2) How to use AMORD, and (3) One way to implement the mechanisms provided by AMORD. This paper is organized into sections. The first section is a short "reference manual" describing the major features of AMORD. Next, we present some examples which illustrate the style of expression encouraged by AMORD. This style makes control information explicit in a rule-manipulable form, and depends on an understanding of the use of non-chronological justifications for program beliefs as a means for determining the current set of beliefs. The third section is a brief description of the Truth Maintenance System employed by AMORD for maintaining these justifications and program beliefs. The fourth section presents a completely annotated interpreter for AMORD, written in SCHEME.MIT Artificial Intelligence Laboratory Department of Defense Advanced Research Projects Agenc

It\u27s a Small World: Enhancing Human Cognition through Virtual Dioramas

2008 S.C. Water Resources Conference - Addressing Water Challenges Facing the State and Regio

Dementia assessment and management in primary care settings: a survey of current provider practices in the United States.

BACKGROUND:Primary care providers (PCPs) are typically the first to screen and evaluate patients for neurocognitive disorders (NCDs), including mild cognitive impairment and dementia. However, data on PCP attitudes and evaluation and management practices are sparse. Our objective was to quantify perspectives and behaviors of PCPs and neurologists with respect to NCD evaluation and management. METHODS:A cross-sectional survey with 150 PCPs and 50 neurologists in the United States who evaluated more than 10 patients over age 55 per month. The 51-item survey assessed clinical practice characteristics, and confidence, perceived barriers, and typical practices when diagnosing and managing patients with NCDs. RESULTS:PCPs and neurologists reported similar confidence and approaches to general medical care and laboratory testing. Though over half of PCPs performed cognitive screening or referred patients for cognitive testing in over 50% of their patients, only 20% reported high confidence in interpreting results of cognitive tests. PCPs were more likely to order CT scans than MRIs, and only 14% of PCPs reported high confidence interpreting brain imaging findings, compared to 70% of specialists. Only 21% of PCPs were highly confident that they correctly recognized when a patient had an NCD, and only 13% were highly confident in making a specific NCD diagnosis (compared to 72 and 44% for neurologists, both p < 0.001). A quarter of all providers identified lack of familiarity with diagnostic criteria for NCD syndromes as a barrier to clinical practice. CONCLUSIONS:This study demonstrates how PCPs approach diagnosis and management of patients with NCDs, and identified areas for improvement in regards to cognitive testing and neuroimaging. This study also identified all providers' lack of familiarity with published diagnostic criteria for NCD syndromes. These findings may inform the development of new policies and interventions to help providers improve the efficacy of their decision processes and deliver better quality care to patients with NCDs

The Beta-Glucan Receptor Dectin-1 Recognizes Specific Morphologies of Aspergillus Fumigatus

Alveolar macrophages represent a first-line innate host defense mechanism for clearing inhaled Aspergillus fumigatus from the lungs, yet contradictory data exist as to which alveolar macrophage recognition receptor is critical for innate immunity to A. fumigatus. Acknowledging that the A. fumigatus cell wall contains a high beta-1,3-glucan content, we questioned whether the beta-glucan receptor dectin-1 played a role in this recognition process. Monoclonal antibody, soluble receptor, and competitive carbohydrate blockage indicated that the alveolar macrophage inflammatory response, specifically the production of tumor necrosis factor-α (TNF-α), interleukin-1α (IL-1α), IL-1β, IL-6, CXCL2/macrophage inflammatory protein-2 (MIP-2), CCL3/macrophage inflammatory protein-1α (MIP-1α), granulocyte-colony stimulating factor (G-CSF), and granulocyte monocyte-CSF (GM-CSF), to live A. fumigatus was dependent on recognition via the beta-glucan receptor dectin-1. The inflammatory response was triggered at the highest level by A. fumigatus swollen conidia and early germlings and correlated to the levels of surface-exposed beta glucans, indicating that dectin-1 preferentially recognizes specific morphological forms of A. fumigatus. Intratracheal administration of A. fumigatus conidia to mice in the presence of a soluble dectin-Fc fusion protein reduced both lung proinflammatory cytokine/chemokine levels and cellular recruitment while modestly increasing the A. fumigatus fungal burden, illustrating the importance of beta-glucan-initiated dectin-1 signaling in defense against this pathogen. Collectively, these data show that dectin-1 is centrally required for the generation of alveolar macrophage proinflammatory responses to A. fumigatus and to our knowledge provides the first in vivo evidence for the role of dectin-1 in fungal innate defense

The Beta-Glucan Receptor Dectin-1 Recognizes Specific Morphologies of Aspergillus fumigatus

Alveolar macrophages represent a first-line innate host defense mechanism for clearing inhaled Aspergillus fumigatus from the lungs, yet contradictory data exist as to which alveolar macrophage recognition receptor is critical for innate immunity to A. fumigatus. Acknowledging that the A. fumigatus cell wall contains a high beta-1,3–glucan content, we questioned whether the beta-glucan receptor dectin-1 played a role in this recognition process. Monoclonal antibody, soluble receptor, and competitive carbohydrate blockage indicated that the alveolar macrophage inflammatory response, specifically the production of tumor necrosis factor-α (TNF-α), interleukin-1α (IL-1α), IL-1β, IL-6, CXCL2/macrophage inflammatory protein-2 (MIP-2), CCL3/macrophage inflammatory protein-1α (MIP-1α), granulocyte-colony stimulating factor (G-CSF), and granulocyte monocyte–CSF (GM-CSF), to live A. fumigatus was dependent on recognition via the beta-glucan receptor dectin-1. The inflammatory response was triggered at the highest level by A. fumigatus swollen conidia and early germlings and correlated to the levels of surface-exposed beta glucans, indicating that dectin-1 preferentially recognizes specific morphological forms of A. fumigatus. Intratracheal administration of A. fumigatus conidia to mice in the presence of a soluble dectin-Fc fusion protein reduced both lung proinflammatory cytokine/chemokine levels and cellular recruitment while modestly increasing the A. fumigatus fungal burden, illustrating the importance of beta-glucan–initiated dectin-1 signaling in defense against this pathogen. Collectively, these data show that dectin-1 is centrally required for the generation of alveolar macrophage proinflammatory responses to A. fumigatus and to our knowledge provides the first in vivo evidence for the role of dectin-1 in fungal innate defense