Using visual analytics to develop situation awareness in astrophysics

We present a novel collaborative visual analytics application for cognitively overloaded users in the astrophysics domain. The system was developed for scientists who need to analyze heterogeneous, complex data under time pressure, and make predictions and time-critical decisions rapidly and correctly under a constant influx of changing data. The Sunfall Data Taking system utilizes several novel visualization and analysis techniques to enable a team of geographically distributed domain specialists to effectively and remotely maneuver a custom-built instrument under challenging operational conditions. Sunfall Data Taking has been in production use for 2 years by a major international astrophysics collaboration (the largest data volume supernova search currently in operation), and has substantially improved the operational efficiency of its users. We describe the system design process by an interdisciplinary team, the system architecture and the results of an informal usability evaluation of the production system by domain experts in the context of Endsley's three levels of situation awareness

Synthetic spectrum methods for three dimensional supernova models.

This dissertation describes some problems associated with synthesizing emergent spectra from three-dimensional supernova envelope models. We confront these problems by developing a three-dimensional implementation of a hybrid Sobolev/Monte Carlo technique. A collection of experiments (extending from the illustrative to the more detailed) are included

Quantitative Spectroscopy of Supernovae for Dark Energy Studies

Detailed quantitative spectroscopy of Type Ia supernovae (SNe~Ia) provides crucial information needed to minimize systematic effects in both ongoing SNe Ia observational programs such as the Nearby Supernova Factory, ESSENCE, and the SuperNova Legacy Survey (SNLS) and in proposed JDEM missions such as SNAP, JEDI, and DESTINY. Quantitative spectroscopy is mandatory to quantify and understand the observational strategy of comparing ``like versus like''. It allows us to explore evolutionary effects, from variations in progenitor metallicity to variations in progenitor age, to variations in dust with cosmological epoch. It also allows us to interpret and quantify the effects of asphericity, as well as different amounts of mixing in the thermonuclear explosion.Comment: White paper submitted to the Dark Energy Task Force, 13 pages, 5 figure

Parallelizing Gaussian Process Calculations in R

We consider parallel computation for Gaussian process calculations to overcome computational and memory constraints on the size of datasets that can be analyzed. Using a hybrid parallelization approach that uses both threading (shared memory) and message-passing (distributed memory), we implement the core linear algebra operations used in spatial statistics and Gaussian process regression in an R package called bigGP that relies on C and MPI. The approach divides the covariance matrix into blocks such that the computational load is balanced across processes while communication between processes is limited. The package provides an API enabling R programmers to implement Gaussian process-based methods by using the distributed linear algebra operations without any C or MPI coding. We illustrate the approach and software by analyzing an astrophysics dataset with n = 67, 275 observations

Diversity of farming systems integrating fish pond aquaculture in the province of Kinshasa in the Democratic Republic of the Congo

Agriculture and aquaculture systems are used by many farmers in various tropical countries of Asia, America and Africa. They have proven their relevancy to increase the productivity of farms by optimising nutrient fluxes and reducing requirements for external fertilisers. This article analysed the current state of fish farming and the way it is integrated with other farm subsystems in the urban/peri-urban and rural areas of Kinshasa, Democratic Republic of Congo. More precisely, it examined the allocation of resources at the farm level, the recovery of helophytes plants, and the fate of fish production choices and it explored the possibility of intensifying these existing integrated farming systems. After a census of ponds in the urban and rural areas of Kinshasa, an on-site survey was conducted on 150 fish pond farms to assess the different activities practiced on farms, the impact of integrating crops and livestock to fish pond aquaculture and the constraints of the system. A total of three thousand and twenty (3020) fish ponds were recorded in the urban and rural areas of Kinshasa. Among these farms integrated aquaculture-agriculture systems exist with a wide diversity of practices (about 79% of farms combined fish with livestock and/or vegetable production). No striking differences between fish farms according to the allocation of resources, fish production method such as monoculture or polyculture, the recovery of helophytes plants and the fate of fish production choice were found depending on the location. However, fish farms were differently managed when combined with agriculture and/or livestock. Regarding the integration of the different subsystems through nutrient fluxes, 11 different movements of material between subsystems were found in integrated farms. However, not all fluxes are equally used in all farms and therefore improvements cannot be generalised. Improvements to be explored are such as making better use of manure pond mud and helophyte plants. For this purpose, proper training of farmers might be critical. Finally, bringing farmers together in cooperatives could also contribute to reduce the cost of purchase and transportation of fish fry and feed

V1647 Orionis: Reinvigorated Accretion and the Re-Appearance of McNeil's Nebula

In late 2003, the young eruptive variable star V1647 Orionis optically brightened by over 5 magnitudes, stayed bright for around 26 months, and then decline to its pre-outburst level. In August 2008 the star was reported to have unexpectedly brightened yet again and we herein present the first detailed observations of this new outburst. Photometrically, the star is now as bright as it ever was following the 2003 eruption. Spectroscopically, a pronounced P Cygni profile is again seen in Halpha with an absorption trough extending to -700 km/s. In the near-infrared, the spectrum now possesses very weak CO overtone bandhead absorption in contrast to the strong bandhead emission seen soon after the 2003 event. Water vapor absorption is also much stronger than previously seen. We discuss the current outburst below and relate it to the earlier event.Comment: 6 pages, 3 figure

Hantavirus and Arenavirus Antibodies in Persons with Occupational Rodent Exposure, North America

Rodents are the principal hosts of Sin Nombre virus, 4 other hantaviruses known to cause hantavirus pulmonary syndrome in North America, and the 3 North American arenaviruses. Serum samples from 757 persons who had worked with rodents in North America and handled neotomine or sigmodontine rodents were tested for antibodies against Sin Nombre virus, Whitewater Arroyo virus, Guanarito virus, and lymphocytic choriomeningitis virus. Antibodies against Sin Nombre virus were found in 4 persons, against Whitewater Arroyo virus or Guanarito virus in 2 persons, and against lymphocytic choriomeningitis virus in none. These results suggest that risk for infection with hantaviruses or arenaviruses usually is low in persons whose occupations entail close physical contact with neotomine or sigmodontine rodents in North Americ