7,057 research outputs found
Opt: A Domain Specific Language for Non-linear Least Squares Optimization in Graphics and Imaging
Many graphics and vision problems can be expressed as non-linear least
squares optimizations of objective functions over visual data, such as images
and meshes. The mathematical descriptions of these functions are extremely
concise, but their implementation in real code is tedious, especially when
optimized for real-time performance on modern GPUs in interactive applications.
In this work, we propose a new language, Opt (available under
http://optlang.org), for writing these objective functions over image- or
graph-structured unknowns concisely and at a high level. Our compiler
automatically transforms these specifications into state-of-the-art GPU solvers
based on Gauss-Newton or Levenberg-Marquardt methods. Opt can generate
different variations of the solver, so users can easily explore tradeoffs in
numerical precision, matrix-free methods, and solver approaches. In our
results, we implement a variety of real-world graphics and vision applications.
Their energy functions are expressible in tens of lines of code, and produce
highly-optimized GPU solver implementations. These solver have performance
competitive with the best published hand-tuned, application-specific GPU
solvers, and orders of magnitude beyond a general-purpose auto-generated
solver
Report of the Inter-American Tropical Tuna Commission for the year 2008
ENGLISH:
The Inter-American Tropical Tuna Commission (IATTC) operates under the authority and direction of a
convention originally entered into by Costa Rica and the United States. The convention, which came into force in
1950, is open to adherence by other governments whose nationals fish for tropical tunas and tuna-like species in
the eastern Pacific Ocean (EPO). Under this provision Panama adhered in 1953, Ecuador in 1961, Mexico in 1964,
Canada in 1968, Japan in 1970, France and Nicaragua in 1973, Vanuatu in 1990, Venezuela in 1992, El Salvador
in 1997, Guatemala in 2000, Peru in 2002, Spain in 2003, the Republic of Korea in 2005, and Colombia in 2007.
Canada withdrew from the IATTC in 1984.
The IATTC's responsibilities are met with two programs, the Tuna-Billfish Program and the Tuna-
Dolphin Program.
SPANISH:
La Comisión Interamericana del Atún Tropical (CIAT) funciona bajo la autoridad y dirección de una convención
suscrita originalmente por Costa Rica y los Estados Unidos de América. La Convención, vigente desde
1950, está abierta a la afiliación de cualquier país cuyos ciudadanos pesquen atunes tropicales y especies afines en
el Océano Pacífico oriental (OPO). Bajo esta estipulación, la República de Panamá se afilió en 1953, Ecuador en
1961, México en 1964, Canadá en 1968, Japón en 1970, Francia y Nicaragua en 1973, Vanuatu en 1990, Venezuela
en 1992, El Salvador en 1997, Guatemala en 2000, Perú en 2002, España en 2003, la República de Corea en 2005,
y Colombia en 2007. Canadá se retiró de la CIAT en 1984.
La CIAT cumple su mandato mediante dos programas, el Programa Atún-Picudo y el Programa
Atún-Delfín
Estudio regional sobre las dimensiones sociales en el manejo de areas marinas protegidas: casos en Costa Rica, Nicaragua, Honduras y Panama
Explora la percepción de las personas residentes en las comunidades costeras vinculadas a los espacios marinos protegidos en Honduras, Nicaragua, Costa Rica y Panamá. Profundiza, a partir de estudios de caso y el análisis comparativo, los temas de gobernanza, derechos humanos y distribución justa y equitativa de beneficios derivados de la conservación. Los resultados destacan que los esfuerzos de conservación marina no han logrado establecer puentes que permitan satisfacer las necesidades sociales. Las comunidades han sido excluidas de los procesos de toma de decisiones, y los costos de la conservación han recaído en las pueblos costeros. Se plantean recomendaciones orientadas hacia el desarrollo de procesos de conservación marina y desarrollo local en aras de tender puentes en la búsqueda de formas y modelos de conservación marina que sean respetuosos de los derechos humanos y promuevan “el buen vivir” de las comunidades en territorios marino-costeros
Testosterone deficiency increases hospital readmission and mortality rates in male patients with heart failure.
BackgroundTestosterone deficiency in patients with heart failure (HF) is associated with decreased exercise capacity and mortality; however, its impact on hospital readmission rate is uncertain. Furthermore, the relationship between testosterone deficiency and sympathetic activation is unknown.ObjectiveWe investigated the role of testosterone level on hospital readmission and mortality rates as well as sympathetic nerve activity in patients with HF.MethodsTotal testosterone (TT) and free testosterone (FT) were measured in 110 hospitalized male patients with a left ventricular ejection fraction < 45% and New York Heart Association classification IV. The patients were placed into low testosterone (LT; n = 66) and normal testosterone (NT; n = 44) groups. Hypogonadism was defined as TT < 300 ng/dL and FT < 131 pmol/L. Muscle sympathetic nerve activity (MSNA) was recorded by microneurography in a subpopulation of 27 patients.ResultsLength of hospital stay was longer in the LT group compared to in the NT group (37 ± 4 vs. 25 ± 4 days; p = 0.008). Similarly, the cumulative hazard of readmission within 1 year was greater in the LT group compared to in the NT group (44% vs. 22%, p = 0.001). In the single-predictor analysis, TT (hazard ratio [HR], 2.77; 95% confidence interval [CI], 1.58-4.85; p = 0.02) predicted hospital readmission within 90 days. In addition, TT (HR, 4.65; 95% CI, 2.67-8.10; p = 0.009) and readmission within 90 days (HR, 3.27; 95% CI, 1.23-8.69; p = 0.02) predicted increased mortality. Neurohumoral activation, as estimated by MSNA, was significantly higher in the LT group compared to in the NT group (65 ± 3 vs. 51 ± 4 bursts/100 heart beats; p < 0.001).ConclusionThese results support the concept that LT is an independent risk factor for hospital readmission within 90 days and increased mortality in patients with HF. Furthermore, increased MSNA was observed in patients with LT
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