Advances in the reconstruction of atom probe tomography data

Key to the integrity of atom probe microanalysis, the tomographic reconstruction is built atom by atom following a simplistic protocol established for previous generations of instruments. In this paper, after a short review of the main reconstruction protocols, we describe recent improvements originating from the use of exact formulae enabling significant reduction of spatial distortions, especially near the edges of the reconstruction. We also show how predictive values for the reconstruction parameters can be derived from electrostatic simulations, and finally introduce parameters varying throughout the analysis.     

Relativistic electron diffraction at the UCLA Pegasus photoinjector laboratory

Electron diffraction holds the promise to yield real-time resolution of atomic motion in an easily accessible environment like a university laboratory at a fraction of the cost of fourth-generation X-ray sources. Currently the limit in time-resolution for conventional electron diffraction is set by how short an electron pulse can be made. A very promising solution to maintain the highest possible beam intensity without excessive pulse broadening from space charge effects is to increase the electron energy to the MeV level where relativistic effects significantly reduce the space charge forces. Rf photoinjectors can in principle deliver up to 10(7)-10(8) electrons packed in bunches of approximately 100-fs length, allowing an unprecedented time resolution and enabling the study of irreversible phenomena by single-shot diffraction patterns. The use of rf photoinjectors as sources for ultrafast electron diffraction has been recently at the center of various theoretical and experimental studies. The UCLA Pegasus laboratory, commissioned in early 2007 as an advanced photoinjector facility, is the only operating system in the country, which has recently demonstrated electron diffraction using a relativistic beam from an rf photoinjector. Due to the use of a state-of-the-art ultrashort photoinjector driver laser system, the beam has been measured to be sub-100-fs long, at least a factor of 5 better than what measured in previous relativistic electron diffraction setups. Moreover, diffraction patterns from various metal targets (titanium and aluminum) have been obtained using the Pegasus beam. One of the main laboratory goals in the near future is to fully develop the rf photoinjector-based ultrafast electron diffraction technique with particular attention to the optimization of the working point of the photoinjector in a low-charge ultrashort pulse regime, and to the development of suitable beam diagnostics.     

Textural and Sensory Properties of Low-Fat Beef Sausages with Added Water and Polysaccharides as Affected by pH and Salt

Low-fat beef sausages with 23% added water, 1 or 2.5% NaCl, 0.5% polysaccharide gums, and pH adjusted to 5.2, 5.6 or 6.2, were analyzed for textural properties. The l - and k -car-rageenans increased (P<0.05) cooking yield, hardness, and bind strength for 1%-salt sausage, but had little effect on the 2.5%-salt sausage. Sausages containing alginate, locust bean gum, and xanthan gum were softer, more deformable, crumbly and slippery (P<0.05), when compared to nongum controls. An increase in pH sharply enhanced the bind strength in all gum treatments. Both the instrumental and sensory panel results suggested that α- and k -carrageen-ans were the only acceptable gums for use in low- or high-salt beef sausage products.     

Characterization of Phase Chemistry and Partitioning in a Family of High-Strength Nickel-Based Superalloys

Metallurgical and Materials Transactions A - A family of novel polycrystalline Ni-based superalloys with varying Ti:Nb ratios has been created using computational alloy design techniques, and...     

Extraction Behavior of Americium and Curium on Selected Extraction Chromatography Resins from Pure Acidic Matrices

Due to the similar chemical properties between the neighboring trivalent actinide elements americium and curium, their extraction behavior is often perceived as indistinguishable. In this work, the characterization of seven extraction chromatography resins (TEVA, TRU, DGA(N), Actinide, Ln, Ln2, and Ln3) for these trivalent actinides from acidic matrices (HNO₃, HCl, and HBr) has provided some evidence to the contrary. In most cases, Am(III) and Cm(III) exhibit identical extraction properties. However, separation is possible with TRU and DGA(N) resins as demonstrated in this study. The extraction shows a strong dependency on the specific anion in solution that follows the order NO₃^?>Br^?>Cl^?.     

Using organizational change procedures to promote the acceptability of prereferral intervention services: The school-based intervention team project.

Prereferral intervention programs represent a consultation-based approach for providing behavioral and/or instructional support to students before considering their eligibility for special class placement. Although research concerning the initial success of these programs has been promising, more information is needed relating program process variables to student outcomes in addition to effective procedures for promoting the adoption of these programs over time. This article describes organizational change procedures that were used to promote the acceptability of a prereferral intervention program at 4 pilot schools. Ss were school-based intervention team members (teachers, teaching assistants, school psychologists, and staff development facilitators) at each school. This article presents evaluation data concerning the program's acceptability to team members and participating teachers, integrity of the consultative process, and effect on numbers of children referred to special education. The implications of these results for school psychologists attempting to promote the acceptability and long-term adoption of prereferral intervention programs are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Robust parameter extraction for decision support using multimodal intensive care data

Digital information flow within the intensive care unit (ICU) continues to grow, with advances in technology and computational biology. Recent developments in the integration and archiving of these data have resulted in new opportunities for data analysis and clinical feedback. New problems associated with ICU databases have also arisen. ICU data are high-dimensional, often sparse, asynchronous and irregularly sampled, as well as being non-stationary, noisy and subject to frequent exogenous perturbations by clinical staff. Relationships between different physiological parameters are usually nonlinear (except within restricted ranges), and the equipment used to measure the observables is often inherently error-prone and biased. The prior probabilities associated with an individual's genetics, pre-existing conditions, lifestyle and ongoing medical treatment all affect prediction and classification accuracy. In this paper, we describe some of the key problems and associated methods that hold promise for robust parameter extraction and data fusion for use in clinical decision support in the ICU.