For true insight into the nature of dark energy, measurements of the precision and accuracy of the Supernova/Acceleration Probe (SNAP) are required. Precursor or scaled-down experiments are unavoidably limited, even for distinguishing the cosmological constant. They can pave the way for, but should not delay, SNAP by developing calibration, refinement, and systematics control (and they will also provide important, exciting astrophysics).

SPARX is an evolutionary project proposed by a collaboration among ENEA-INFN-CNR-Universita di Roma Tor Vergata aiming at the construction of a FELSASE X-ray source in the Tor Vergata Campus. The first phase of the SPARX project, funded by Government Agencies, will be focused on R&D activity on critical components and techniques for future X-ray facilities as described in this paper.

We introduce a low Mach number equation set for the large-scale numerical simulation of carbon-oxygen white dwarfs experiencing a thermonuclear deflagration. Since most of the interesting physics in a Type Ia supernova transpires at Mach numbers from 0.01 to 0.1, such an approach enables both a considerable increase in accuracy and savings in computer time compared with frequently used compressible codes. Our equation set is derived from the fully compressible equations using low Mach number asymptotics, but without any restriction on the size of perturbations in density or temperature. Comparisons with simulations that use the fully compressible equations validate the low Mach number model in regimes where both are applicable. Comparisons to simulations based on the more traditional an elastic approximation also demonstrate the agreement of these models in the regime for which the anelastic approximation is valid. For low Mach number flows with potentially finite amplitude variations in density and temperature, the low Mach number model overcomes the limitations of each of the more traditional models and can serve as the basis for an accurate and efficient simulation tool.

Daily newspaper from Altus, Oklahoma that includes local, state, and national news along with advertising.

Weekly newspaper from Grandview, Texas that includes local, state, and national news along with advertising.

Photograph of the back of the enlisted mens' barracks at Fort Davis. There is a small staircase leading up to the long porch.

Photograph of the Commanding Officer's Quarters at Fort Davis. The building is made of red brick, and has a large front porch. Identical buildings are visible to the left and right of the officer's quarters.

Photograph of a plaque outside the Commanding Officer's Quarters. It says: "Commanding Officer's Quarters: This building served as the residence for the commanding officer. Construction of the house began in 1867 under the direction of Lieutenant Colonel Wesley Merritt, who was the first to move in and call it "home". Today it is furnished to the time when Colonel Benjamin H. Grierson, commander of the black Tenth U.S.Cavalry, and his family lived here, 1882-1885."

Photograph of the Commanding Officer's Quarters cistern at Fort Davis. The cistern is empty and roped off, and there is a sign with the word "cistern" placed in the middle of the roped off area.

Photograph of the back porch and Post Hospital at the Commanding Officer's Quarters in Fort Davis. The building is made of red brick, and the windows have green shutters. Another building is visible in the background, in front of a steep, rocky hill.

Photograph of the Commanding Officer's Quarters at Fort Davis, viewed through the front door. The back door is open as well. The inside of the building is dark.

Photograph of the front and side of the Commissary at Fort Davis. It is a red adobe building with a front porch, several windows, and a second door on the side of the building. The rocky ridge of a mountain is visible behind the building.

Photograph of the quoin details on one corner of the commissary at Fort Davis. The porch is partially visible to the left, and a window and doorway are on the right.

Photograph of an adobe wall at Fort Davis.

Photograph of an Officer's Quarters building at Fort Davis. It is made of adobe, and has a long front porch. Other buildings are visible beyond it.

Photograph of a dilapidated Officer's Quarters building at Fort Davis. It has a large front porch. Other buildings are visible beyond it.

Photograph of a row of identical Officer's Quarters at Fort Davis.

Photograph of the ruins of an unnamed building at Fort Davis.

Photograph of ruins at Fort Davis.

Photograph of the ruins of several buildings at Fort Davis.

Photograph of ruins at Fort Davis, with the Junior Officer's Quarters in background.

Photograph of ruins at Fort Davis. There is a house and mountains in the background.

Photograph of ruins of an adobe building at Fort Davis.

Photograph of the ruins of an adobe building at Fort Davis.