Reconciling Semiclassical and Bohmian Mechanics: III. Scattering states for continuous potentials

In a previous paper [J. Chem. Phys. 121 4501 (2004)] a unique bipolar decomposition, Psi = Psi1 + Psi2 was presented for stationary bound states Psi of the one-dimensional Schroedinger equation, such that the components Psi1 and Psi2 approach their semiclassical WKB analogs in the large action limit. The corresponding bipolar quantum trajectories, as defined in the usual Bohmian mechanical formulation, are classical-like and well-behaved, even when Psi has many nodes, or is wildly oscillatory. A modification for discontinuous potential stationary stattering states was presented in a second paper [J. Chem. Phys. 124 034115 (2006)], whose generalization for continuous potentials is given here. The result is an exact quantum scattering methodology using classical trajectories. For additional convenience in handling the tunneling case, a constant velocity trajectory version is also developed.Comment: 16 pages and 14 figure

1991: Abilene Christian College Bible Lectures - Full Text

PRAISING GOD: THEMES FROM THE PSALMS Being the Abilene Christian University Annual Bible Lectures 1991 Published by ACU PRESS 1648 Campus Court Abilene, Texas 7960

Modules for Experiments in Stellar Astrophysics (MESA)

Stellar physics and evolution calculations enable a broad range of research in astrophysics. Modules for Experiments in Stellar Astrophysics (MESA) is a suite of open source libraries for a wide range of applications in computational stellar astrophysics. A newly designed 1-D stellar evolution module, MESA star, combines many of the numerical and physics modules for simulations of a wide range of stellar evolution scenarios ranging from very-low mass to massive stars, including advanced evolutionary phases. MESA star solves the fully coupled structure and composition equations simultaneously. It uses adaptive mesh refinement and sophisticated timestep controls, and supports shared memory parallelism based on OpenMP. Independently usable modules provide equation of state, opacity, nuclear reaction rates, and atmosphere boundary conditions. Each module is constructed as a separate Fortran 95 library with its own public interface. Examples include comparisons to other codes and show evolutionary tracks of very low mass stars, brown dwarfs, and gas giant planets; the complete evolution of a 1 Msun star from the pre-main sequence to a cooling white dwarf; the Solar sound speed profile; the evolution of intermediate mass stars through the thermal pulses on the He-shell burning AGB phase; the interior structure of slowly pulsating B Stars and Beta Cepheids; evolutionary tracks of massive stars from the pre-main sequence to the onset of core collapse; stars undergoing Roche lobe overflow; and accretion onto a neutron star. Instructions for downloading and installing MESA can be found on the project web site (http://mesa.sourceforge.net/).Comment: 110 pages, 39 figures; submitted to ApJS; visit the MESA website at http://mesa.sourceforge.ne

Developing priority variables ("ecosystem Essential Ocean Variables" — eEOVs) for observing dynamics and change in Southern Ocean ecosystems

Reliable statements about variability and change in marine ecosystems and their underlying causes are needed to report on their status and to guide management. Here we use the Framework on Ocean Observing (FOO) to begin developing ecosystem Essential Ocean Variables (eEOVs) for the Southern Ocean Observing System (SOOS). An eEOV is a defined biological or ecological quantity, which is derived from field observations, and which contributes significantly to assessments of Southern Ocean ecosystems. Here, assessments are concerned with estimating status and trends in ecosystem properties, attribution of trends to causes, and predicting future trajectories. eEOVs should be feasible to collect at appropriate spatial and temporal scales and are useful to the extent that they contribute to direct estimation of trends and/or attribution, and/or development of ecological (statistical or simulation) models to support assessments. In this paper we outline the rationale, including establishing a set of criteria, for selecting eEOVs for the SOOS and develop a list of candidate eEOVs for further evaluation. Other than habitat variables, nine types of eEOVs for Southern Ocean taxa are identified within three classes: state (magnitude, genetic/species, size spectrum), predator–prey (diet, foraging range), and autecology (phenology, reproductive rate, individual growth rate, detritus). Most candidates for the suite of Southern Ocean taxa relate to state or diet. Candidate autecological eEOVs have not been developed other than for marine mammals and birds. We consider some of the spatial and temporal issues that will influence the adoption and use of eEOVs in an observing system in the Southern Ocean, noting that existing operations and platforms potentially provide coverage of the four main sectors of the region — the East and West Pacific, Atlantic and Indian. Lastly, we discuss the importance of simulation modelling in helping with the design of the observing system in the long term. Regional boundary: south of 30°S

Constrained distance transforms for spatial atlas registration

BACKGROUND: Spatial frameworks are used to capture organ or whole organism image data in biomedical research. The registration of large biomedical volumetric images is a complex and challenging task, but one that is required for spatially mapped biomedical atlas systems. In most biomedical applications the transforms required are non-rigid and may involve significant deformation relating to variation in pose, natural variation and mutation. Here we develop a new technique to establish such transformations for mapping data that cannot be achieved by existing approaches and that can be used interactively for expert editorial review. RESULTS: This paper presents the Constrained Distance Transform (CDT), a novel method for interactive image registration. The CDT uses radial basis function transforms with distances constrained to geodesics within the domains of the objects being registered. A geodesic distance algorithm is discussed and evaluated. Examples of registration using the CDT are presented. CONCLUSION: The CDT method is shown to be capable of simultaneous registration and foreground segmentation even when very large deformations are required

The Impact of Recombination on Nucleotide Substitutions in the Human Genome

Unraveling the evolutionary forces responsible for variations of neutral substitution patterns among taxa or along genomes is a major issue for detecting selection within sequences. Mammalian genomes show large-scale regional variations of GC-content (the isochores), but the substitution processes at the origin of this structure are poorly understood. We analyzed the pattern of neutral substitutions in 1 Gb of primate non-coding regions. We show that the GC-content toward which sequences are evolving is strongly negatively correlated to the distance to telomeres and positively correlated to the rate of crossovers (R2 = 47%). This demonstrates that recombination has a major impact on substitution patterns in human, driving the evolution of GC-content. The evolution of GC-content correlates much more strongly with male than with female crossover rate, which rules out selectionist models for the evolution of isochores. This effect of recombination is most probably a consequence of the neutral process of biased gene conversion (BGC) occurring within recombination hotspots. We show that the predictions of this model fit very well with the observed substitution patterns in the human genome. This model notably explains the positive correlation between substitution rate and recombination rate. Theoretical calculations indicate that variations in population size or density in recombination hotspots can have a very strong impact on the evolution of base composition. Furthermore, recombination hotspots can create strong substitution hotspots. This molecular drive affects both coding and non-coding regions. We therefore conclude that along with mutation, selection and drift, BGC is one of the major factors driving genome evolution. Our results also shed light on variations in the rate of crossover relative to non-crossover events, along chromosomes and according to sex, and also on the conservation of hotspot density between human and chimp

Police Chiefs\u27 Use and Executive Subordinates\u27 Perceived Use of Non-Performance and Performance Based Criteria in Promotional Decisions: Organizational Mobility Channels

The purpose of this study was to investigate police promotion and channels of mobility from an appointed perspective by those who do the appointments, as well as those chosen for the appointment. There were two ultimate goals of this study. The first was to describe the characteristics of police chiefs and subordinate police executives, and the importance of non-performance based criteria and performance based criteria used in promotion decision making by police chiefs and perceptions of use by subordinate police executives. The second was to extend the intra-organizational mobility model developed by Beehr and Taber (1993), with four additional non-performance based criteria of office politics, trust, personality, and physical attractiveness, to examine its explanatory power, and the reliability and validity of the new factors in the context of the original model. This study used a quantitative, non-experimental, descriptive, exploratory (comparative), and correlation (explanatory) survey research design to examine the relationships between variables. The study compared the criteria used for promotion; performance and/or non-performance criteria, by surveying selected chiefs, sheriffs, and directors, identified as the agency head, and the perceptions of those who were appointed to upper command level positions by their respective agency head. The sampling plan involved obtaining an active member list from the IACP of Chiefs and Subordinate Police Executives. Twelve thousand-seven hundred-seventy (12,770) Chiefs and Subordinate Police Executives in the United States that are active members of the IACP were invited to participate in the one month survey. Those members of the accessible population that submitted the survey constituted the final data producing sample. Five different scales were used in this study, measuring reliable and exceptional performance, luck and favoritism, office politics, demographics, trust, personality, and physical attractiveness. Findings indicated that all scales were valid and reliable instruments, including the 38-Item Intra-Organizational Mobility Channels Questionnaire (IMCQ), which was modified by the researcher from Beer and Taber\u27s (1993) original Four Factor IMCQ. Findings also identified that chiefs rate reliable performance, personality, and trust criteria significantly more important than subordinate police executives in promotion decisions. Subordinate police executives rated exceptional performance, demographic, luck and favoritism, and office politics criteria significantly more important than police chiefs in promotion decisions

Tarain wreck: the end of the conservative revolution (and not a moment too soon)

This in-depth analysis reveals three very salient facts: haltred of government has been a core value of the conservative movement from its inception: the behavior of the George W Bush administration has mirrored that of the reagan administration in every important way: and, until hurricane Katrina revealed in 2005 that the emperor had no clothes, movement conservatives were the president's strongest supporters and closest allie

Train wreck: The end of the conservative revolution (and not a moment too son)

vii,227 p.;24 c