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Three-Dimensional Aberration-Corrected Scanning Transmission Electron Microscopy for Biology (open access)

Three-Dimensional Aberration-Corrected Scanning Transmission Electron Microscopy for Biology

Recent instrumental developments have enabled greatly improved resolution of scanning transmission electron microscopes (STEM) through aberration correction. An additional and previously unanticipated advantage of aberration correction is the greatly improved depth sensitivity that has led to the reconstruction of a three-dimensional (3D) image from a focal series. In this chapter the potential of aberration-corrected 3D STEM to provide major improvements in the imaging capabilities for biological samples will be discussed. This chapter contains a brief overview ofthe various high-resolution 3D imaging techniques, a historical perspective of the development of STEM, first estimates of the dose-limited axial and lateral resolution on biological samples and initial experiments on stained thin sections.
Date: January 1, 2007
Creator: De Jonge, Niels; Sougrat, Rachid; Pennycook, Stephen J; Peckys, Diana B & Lupini, Andrew R
System: The UNT Digital Library
Pestoides F, and Atypical Yersinia pestis Strain from the Former Soviet Union (open access)

Pestoides F, and Atypical Yersinia pestis Strain from the Former Soviet Union

Unlike the classical Yersinia pestis strains, members of an atypical group of Y. pestis from Central Asia, denominated Y. pestis subspecies caucasica (also known as one of several pestoides types), are distinguished by a number of characteristics including their ability to ferment rhamnose and melibiose, their lacking the small plasmid encoding the plasminogen activator (pla) and pesticin, and their exceptionally large variants of the virulence plasmid pMT (encoding murine toxin and capsular antigen). We have obtained the entire genome sequence of Y. pestis Pestoides F, an isolate from the former Soviet Union that has enabled us to carryout a comprehensive genome-wide comparison of this organism's genomic content against the six published sequences of Y. pestis and their Y. pseudotuberculosis ancestor. Based on classical glycerol fermentation (+ve) and nitrate reduction (+ve) Y. pestis Pestoides F is an isolate that belongs to the biovar antiqua. This strain is unusual in other characteristics such as the fact that it carries a non-consensus V antigen (lcrV) sequence, and that unlike other Pla{sup -} strains, Pestoides F retains virulence by the parenteral and aerosol routes. The chromosome of Pestoides F is 4,517,345 bp in size comprising some 3,936 predicted coding sequences, while its pCD and …
Date: January 5, 2007
Creator: Garcia, E.; Worsham, P.; Bearden, S.; Malfatti, S.; Lang, D.; Larimer, F. et al.
System: The UNT Digital Library
Cavity Microwave Searches for Cosmological Axions (open access)

Cavity Microwave Searches for Cosmological Axions

This chapter will cover the search for dark matter axions based on microwave cavity experiments proposed by Pierre Sikivie. We will start with a brief overview of halo dark matter and the axion as a candidate. The principle of resonant conversion of axions in an external magnetic field will be described as well as practical considerations in optimizing the experiment as a signal-to-noise problem. A major focus of this chapter will be the two complementary strategies for ultra-low noise detection of the microwave photons--the 'photon-as-wave' approach (i.e. conventional heterojunction amplifiers and soon to be quantum-limited SQUID devices), and 'photon-as-particle' (i.e. Rydberg-atom single-quantum detection). Experimental results will be presented; these experiments have already reached well into the range of sensitivity to exclude plausible axion models, for limited ranges of mass. The section will conclude with a discussion of future plans and challenges for the microwave cavity experiment.
Date: January 22, 2007
Creator: Carosi, G. & van Bibber, K.
System: The UNT Digital Library
Soil Survey of King County, Texas (open access)

Soil Survey of King County, Texas

Text describes the area, climate, agricultural history and statistics, soil-survey methods and definitions, soils and crops, land uses and agricultural methods, irrigation, and morphology and genesis of soils of King County, Texas.
Date: January 2007
Creator: United States. Natural Resources Conservation Service.
System: The Portal to Texas History
Soil Survey of Lee County, Texas (open access)

Soil Survey of Lee County, Texas

Text describes the area, climate, agricultural history and statistics, soil-survey methods and definitions, soils and crops, land uses and agricultural methods, irrigation, and morphology and genesis of soils of Lee County, Texas.
Date: January 2007
Creator: United States. Natural Resources Conservation Service.
System: The Portal to Texas History
Electron Holography of Electromagnetic Fields - Recent Theoretical Advances. (open access)

Electron Holography of Electromagnetic Fields - Recent Theoretical Advances.

It has been shown in this work that the Fourier space approach can be fruitfully applied to the calculation of the fields and the associated electron optical phase shift of several magnetic and electrostatic structures, like superconducting vortices in conventional and high-T{sub c} superconductors, reverse biased p-n junctions, magnetic domains and nanoparticles. In all these cases, this novel approach has led to unexpected but extremely interesting results, very often expressed in analytical form, which allow the quantitative and reliable interpretation of the experimental data collected by means of electron holography or of more conventional Lorentz microscopy techniques. Moreover, it is worth recalling that whenever long-range electromagnetic fields are involved, a physical model of the object under investigation is necessary in order to take into account correctly the perturbation of the reference wave induced by the tail of the field protruding into the vacuum. For these reasons, we believe that the Fourier space approach for phase computations we have introduced and discussed in this chapter will represent an invaluable tool for the investigation of electromagnetic fields at the meso- and nano-scale.
Date: January 1, 2007
Creator: Beleggia, M.; Pozzi, G. & Tonomura, A.
System: The UNT Digital Library
Self-Organized Criticality and Cellular Automata (open access)

Self-Organized Criticality and Cellular Automata

Cellular automata provide a fascinating class of dynamical systems based on very simple rules of evolution yet capable of displaying highly complex behavior. These include simplified models for many phenomena seen in nature. Among other things, they provide insight into self-organized criticality, wherein dissipative systems naturally drive themselves to a critical state with important phenomena occurring over a wide range of length and the scales. This article begins with an overview of self-organized criticality. This is followed by a discussion of a few examples of simple cellular automaton systems, some of which may exhibit critical behavior. Finally, some of the fascinating exact mathematical properties of the Bak-Tang-Wiesenfeld sand-pile model [1] are discussed.
Date: January 1, 2007
Creator: Creutz, M.
System: The UNT Digital Library
[Abilene City Council Minutes: 2007] (open access)

[Abilene City Council Minutes: 2007]

Ledger containing minutes of the City Council in Abilene, Texas documenting the group's discussions and activities from January 11, 2007 to December 20, 2007.
Date: 2007-01-11/2007-12-20
Creator: Abilene (Tex.)
System: The Portal to Texas History
Pulse Radiolysis in Supercritical Rare Gas Fluids (open access)

Pulse Radiolysis in Supercritical Rare Gas Fluids

Recently, supercritical fluids have become quite popular in chemical and semiconductor industries for applications in chemical synthesis, extraction, separation processes, and surface cleaning. These applications are based on: the high dissolving power due to density build-up around solute molecules, and the ability to tune the conditions of a supercritical fluid, such as density and temperature, that are most suitable for a particular reaction. The rare gases also possess these properties and have the added advantage of being supercritical at room temperature. Information about the density buildup around both charged and neutral species can be obtained from fundamental studies of volume changes in the reactions of charged species in supercritical fluids. Volume changes are much larger in supercritical fluids than in ordinary solvents because of their higher compressibility. Hopefully basic studies, such as discussed here, of the behavior of charged species in supercritical gases will provide information useful for the utilization of these solvents in industrial applications.
Date: January 1, 2007
Creator: Holroyd, R.
System: The UNT Digital Library
[News Story Log: January 1 to June 30, 2007] (open access)

[News Story Log: January 1 to June 30, 2007]

Logbook from the KXAS-TV/NBC station in Fort Worth, Texas, documenting the names, locations, and run-times of video-taped news segments that aired each day from January through June in 2007.
Date: 2007-01/2007-06
Creator: KXAS-TV (Television station : Fort Worth, Tex.)
System: The UNT Digital Library
Curatorial Facility Certification Program: Benchmarking Excellence (open access)

Curatorial Facility Certification Program: Benchmarking Excellence

Document providing information for applicants who want to certify a facility in Texas to house and manage certain cultural resources, antiquities, etc.: "The purpose of this handbook is to guide the applicant curatorial facility through the entire [Curatorial Facility Certification Program] process, from Application through to Self Evaluation and Field Review" (p. 5).
Date: January 25, 2007
Creator: Texas Historical Commission
System: The Portal to Texas History
FCC Record, Volume 22, No. 2, Pages 443 to 1054, January 16 - January 26, 2007 (open access)

FCC Record, Volume 22, No. 2, Pages 443 to 1054, January 16 - January 26, 2007

Biweekly, comprehensive compilation of decisions, reports, public notices, and other documents of the U.S. Federal Communications Commission.
Date: January 2007
Creator: United States. Federal Communications Commission.
System: The UNT Digital Library
FCC Record, Volume 22, No. 3, Pages 1055 to 2007, January 29 - January 31, 2007 (open access)

FCC Record, Volume 22, No. 3, Pages 1055 to 2007, January 29 - January 31, 2007

Biweekly, comprehensive compilation of decisions, reports, public notices, and other documents of the U.S. Federal Communications Commission.
Date: January 2007
Creator: United States. Federal Communications Commission.
System: The UNT Digital Library
FCC Record, Volume 22, No. 1, Pages 1 to 432, January 3 - January 12, 2007 (open access)

FCC Record, Volume 22, No. 1, Pages 1 to 432, January 3 - January 12, 2007

Biweekly, comprehensive compilation of decisions, reports, public notices, and other documents of the U.S. Federal Communications Commission.
Date: January 2007
Creator: United States. Federal Communications Commission.
System: The UNT Digital Library