Analysis of community structure in networks of correlated data (open access)

Analysis of community structure in networks of correlated data

We present a reformulation of modularity that allows the analysis of the community structure in networks of correlated data. The new modularity preserves the probabilistic semantics of the original definition even when the network is directed, weighted, signed, and has self-loops. This is the most general condition one can find in the study of any network, in particular those defined from correlated data. We apply our results to a real network of correlated data between stores in the city of Lyon (France).
Date: December 25, 2008
Creator: Gomez, S.; Jensen, P. & Arenas, A.
Object Type: Article
System: The UNT Digital Library
Quantum efficiency characterization of LBNL CCD's Part 1: theQuantum Efficiency Machine (open access)

Quantum efficiency characterization of LBNL CCD's Part 1: theQuantum Efficiency Machine

Instrumentation was developed in 2004 and 2005 to measurethe quantum efficiency of the Lawrence Berkeley National Lab(LBNL)total-depletion CCD's, intended for astronomy and spaceapplications. This paper describes the basic instrument. Although it isconventional even to the parts list, there are important innovations. Axenon arc light source was chosen for its high blue/UV and low red/IRoutput as compared with a tungsten light. Intensity stabilization hasbeen difficult, but sinceonly flux ratios matter this is not critical.Between the light source andan Oriel MS257 monochromator are a shutterand two filter wheels. High-bandpass and low-bandpass filter pairsisolate the 150-nm wide bands appropriate to the wavelength, thusminimizing scattered light and providing order blocking. Light from theauxiliary port enters a 20-inch optical sphere, and the 4-inch outputport is at right angles to the input port. An 80 cm drift space producesnear-uniform illumination on the CCD. Next to the cold CCD inside thehorizontal dewar is a calibrated reference photodiode which is regulatedto the PD calibration temperature, 25$^\circ$ C. The ratio ofthe CCD andin-dewar reference PD signals provides the QE measurement. Additionalcross-calibration to a PD on the integrating spherepermitslower-intensity exposures.
Date: December 25, 2005
Creator: Groom, Donald E.; Bebek, Christopher J.; Fabricius, Maximilian; Karcher, Armin; Kolbe, William F.; Roe, Natalie A. et al.
Object Type: Article
System: The UNT Digital Library
RbGd{sub 2}Br{sub 7}:Ce scintillators for gamma ray and thermal neutron detection (open access)

RbGd{sub 2}Br{sub 7}:Ce scintillators for gamma ray and thermal neutron detection

In this paper, we report on gamma ray and thermal neutron detection with RbGd2Br7:Ce scintillators. RbGd2Br7:Ce (RGB) is a new scintillator material, which shows high light output (56,000 photons/MeV) and has a fast principal decay constant (45 ns) when doped with 10 percent Ce. These properties make RGB an attractive scintillator for g-ray detection. Also, due to the presence of Gd as a constituent, RGB has a high cross section for thermal neutron absorption and can achieve close to 100 percent stopping efficiency with 0.5 mm thick RGB crystals. Crystals of RGB with three different Ce concentrations (0.1, 5, and 10 percent) have been grown and their basic scintillation properties such as light output, decay time, and emission spectrum have been measured. In addition, high efficiency thermal neutron detection has been confirmed in our studies.
Date: December 25, 2001
Creator: Shah, Kanai S.; Cirignano, Leonard; Grazioso, Ronald; Klugerman, Misha; Bennett, Paul R.; Gupta, Tapan K. et al.
Object Type: Article
System: The UNT Digital Library
Texas Register, Volume 34, Number 52, Pages 9265-9546, December 25, 2009 (open access)

Texas Register, Volume 34, Number 52, Pages 9265-9546, December 25, 2009

A weekly publication, the Texas Register serves as the journal of state agency rulemaking for Texas. Information published in the Texas Register includes proposed, adopted, withdrawn and emergency rule actions, notices of state agency review of agency rules, governor's appointments, attorney general opinions, and miscellaneous documents such as requests for proposals. After adoption, these rulemaking actions are codified into the Texas Administrative Code.
Date: December 25, 2009
Creator: Texas. Secretary of State.
Object Type: Journal/Magazine/Newsletter
System: The Portal to Texas History