Relativistic precession of quantum elliptical states in the Coulomb potential

A special relativistic perturbation to non-relativistic quantum mechanics is shown to lead to the special relativistic prediction for the rate of precession for quantum states in the Coulomb potential. This behavior is shown using SO(4) coherent states as examples. These states are localized on Kepler ellipses and precess in the presence of a relativistic perturbation.Comment: 10 pages, 3 figures, submitted to Am.J.Phys, revised for style, improved figure

Electrochemistry and Spectroscopy of Sulfate and Thiosulfate Complexes of Iron Porphyrins

The electrochemical and spectroscopic properties of the complex formed by the addition of thiosulfate to ferric porphyrins were examined. The NMR spectrum of the thiosulfate–ferric porphyrin complex was consistent with a high-spin ferric complex, while the EPR spectrum at liquid nitrogen temperatures indicated that the complex under these conditions was low-spin. Such behavior has been previously observed for other ferric porphyrin complexes. The visible spectra were characterized by a shift in the Soret band to higher energies, with smaller changes in the longer wavelength region. The complex was reasonably stable in DMF, but slowly reduced over several hours to FeII(TPP) and S4O6 2−. The voltammetric behavior of the thiosulfate complex in DMF consists of two waves, the first of which was irreversible. The ferric/ferrous reduction in the presence of thiosulfate was shifted negatively about 400 mV, compared to the Fe(TPP)(Cl) reduction. The visible, NMR and EPR spectra were most consistent with a Fe–S bonded ferric porphyrin–thiosulfate complex, Fe(P)(SSO3)−. The kinetics of the reduction of ferric porphyrin by thiosulfate in DMSO indicated an autocatalytic mechanism, where the first step is the formation of the catalyst. The identity of the catalyst could not be determined because it must be present at low concentrations, but it is formed from the reaction of the ferric complex with thiosulfate. Coordination of thiosulfate to the porphyrin was not necessary for the reduction to occur, and the reduction of Fe(TPP)(Cl) by thiosulfate was accelerated by the addition of sulfate. Under these conditions, sulfate had replaced thiosulfate as the axial ligand for the ferric porphyrin. In the presence of sulfate, the reduction occurred in a single kinetic pseudo-first order step. The voltammetry, spectroelectrochemistry and kinetics for the reaction of thiosulfate with ferric porphyrins were examined. A rapid reaction between ferric porphyrins and thiosulfate was observed in DMF. The reaction was complex, involving the formation of a catalytic intermediate. Window factor analysis and multivariate curve resolution were used to deconvolute the kinetic data

An investigation into the numerical prediction of boundary layer transition using the K.Y. Chien turbulence model

Assessments were made of the simulation capabilities of transition models developed at the University of Minnesota, as applied to the Launder-Sharma and Lam-Bremhorst two-equation turbulence models, and at The University of Texas at Austin, as applied to the K. Y. Chien two-equation turbulence model. A major shortcoming in the use of the basic K. Y. Chien turbulence model for low-Reynolds number flows was identified. The problem with the Chien model involved premature start of natural transition and a damped response as the simulation moved to fully turbulent flow at the end of transition. This is in contrast to the other two-equation turbulence models at comparable freestream turbulence conditions. The damping of the transition response of the Chien turbulence model leads to an inaccurate estimate of the start and end of transition for freestream turbulence levels greater than 1.0 percent and to difficulty in calculating proper model constants for the transition model

Strategic approaches to science and technology in development

Watson, Crawford, and Farley examine the ways in which science and technology (S&T) support poverty alleviation and economic development and how these themes have been given emphasis or short shrift in various areas of the World Bank's work. Central to their thesis is the now well-established argument that development will increasingly depend on a country's ability to understand, interpret, select, adapt, use, transmit, diffuse, produce, and commercialize scientific and technological knowledge in ways appropriate to its culture, aspirations, and level of development. The authors go beyond this tenet, analyzing the importance of S&T for development within specific sectors. They present policy options for enhancing the effectiveness of S&T systems in developing countries, review previous experience of the World Bank and other donors in supporting S&T, and suggest changes that the World Bank and its partners can adopt to increase the impact of the work currently undertaken in S&T. The authors'main messages are: 1) S&T has always been important for development, but the unprecedented pace of advancement of scientific knowledge is rapidly creating new opportunities for and threats to development. 2) Most developing countries are largely unprepared to deal with the changes that S&T advancement will bring. 3) The World Bank's numerous actions in various domains of S&T could be more effective in producing the needed capacity improvements in client countries. 4) The World Bank could have a greater impact if it paid increased attention to S&T in education, health, rural development, private sector development, and the environment. The strategy emphasizes four S&T policy areas: education and human resources development, the private sector, the public sector, and information communications technologies.Public Health Promotion,Environmental Economics&Policies,ICT Policy and Strategies,Decentralization,Health Economics&Finance,Environmental Economics&Policies,ICT Policy and Strategies,Health Economics&Finance,Poverty Assessment,Agricultural Research

Metamorphic Code Generation Using LLVM

Each instance of metamorphic software changes its internal structure, but the function remains essentially the same. Such metamorphism has been used primarily by malware writers as a means of evading signature-based detection. However, metamorphism also has potential beneficial uses in fields related to software protection. In this research, we develop a practical framework within the LLVM compiler that automatically generates metamorphic code, where the user has well-defined control over the degree of morphing applied to the code. We analyze the effectiveness of this metamorphic generator based on Hidden Markov Model (HMM) analysis, and discover that HMMs are effective at detection up to ~285% code added

Hox Genes as Synchronized Temporal Regulators: Implications for Morphological Innovation

Abstract In vertebrates, clusters of Hox genes express in a nested and hierarchical fashion to endow the embryo’s segments with discrete identities. Later in development, members of the same gene family are employed again to pattern the limb, intestinal, and reproductive systems. A careful analysis of the morphologies of Hox mutant mice suggests that the genes provide qualitatively different cues during the specification of segments than they do during the development of more recently derived structures. In addition to the regulatory differences noted by others, the activity of Hox genes during specification of the vertebrate metameres in some recent deletion experiments is inconsistent with a role for them as strictly spatial determinants. On the contrary, the phenotypes observed are suggestive of a role for them as elements of a generic time-keeping mechanism. By contrast, the specification of more recent evolutionary structures appears to be more spatial andgene-specific. These differences in role and effect may suggest some simple mechanisms by which the Hox clusters operate, and rules by which gene networks can be diverted to create new structures over the course of evolution. Specific predictions and experiments are proposed

Transformations in null mutants of Hox genes: do they represent intercalary regenerates?

In the minds of many, Hox gene null mutant phenotypes have confirmed the direct role that these genes play in specifying the pattern of vertebrate embryos. The genes are envisaged as defining discrete spatial domains and, subsequently, conferring specific segmental identities on cells undergoing differentiation along the antero-posterior axis. However, several aspects of the observed mutant phenotypes are inconsistent with this view. These include: the appearance of other, unexpected transformations along the dorsal axis; the occurrence of mirror-image duplications; and the development of anomalies outside the established domains of normal Hox gene expression. In this paper, Hox gene disruptions are shown to elicit regeneration-like responses in tissues confronted with discontinuities in axial identity. The polarities and orientations of transformed segments which emerge as a consequence of this response obey the rules of distal transformation and intercalary regeneration. In addition, the incidence of periodic anomalies suggests that the initial steps of Hox-mediated patterning occurs in Hensen\u27s node. As gastrulation proceeds, mesoderm cell cycle kinetics impose constraints upon subsequent cellular differentiation. This results in the delayed manifestation of transformations along the antero-posterior axis. Finally, a paradigm is sketched in which temporal, rather than spatial axial determinants direct differentiation. Specific, testable predictions are made about the role of Hox genes in the establishment of segmental identity. In the minds of many, Hox gene null mutant phenotypes have confirmed the direct role that these genes play in specifying the pattern of vertebrate embryos. The genes are envisaged as defining discrete spatial domains and, subsequently, conferring specific segmental identities on cells undergoing differentiation along the antero-posterior axis. However, several aspects of the observed mutant phenotypes are inconsistent with this view. These include: the appearance of other, unexpected transformations along the dorsal axis; the occurrence of mirror-image duplications; and the development of anomalies outside the established domains of normal Hox gene expression. In this paper, Hox gene disruptions are shown to elicit regeneration-like responses in tissues confronted with discontinuities in axial identity. The polarities and orientations of transformed segments which emerge as a consequence of this response obey the rules of distal transformation and intercalary regeneration. In addition, the incidence of periodic anomalies suggests that the initial steps of Hox-mediated patterning occurs in Hensen\u27s node. As gastrulation proceeds, mesoderm cell cycle kinetics impose constraints upon subsequent cellular differentiation. This results in the delayed manifestation of transformations along the antero-posterior axis. Finally, a paradigm is sketched in which temporal, rather than spatial axial determinants direct differentiation. Specific, testable predictions are made about the role of Hox genes in the establishment of segmental identity

Evolution and Emergence: a Re-Evaluation of the New Synthesis

The modern obsession with methodological reductionism in some areas of biology is arguably a product of the exquisitely precise tools now available to dissect problems. Reductionist approaches assume that an understanding of atomized parts will be sufficient to approximate an understanding of the whole. Ironically, the sheer success of this approach and the consequent volume of data generated, particularly as a result of the genome projects, has made comprehension of the larger picture problematic. Consequently, historical patterns of more phenomenologically oriented analyses are re-emerging. This impulse is not new: Gould and Lewontin (1979) argued for a less reductionist view of evolution. They argue that an intense focus upon individual traits risks confusing evolutionary selection with the indirect consequences of other architectural decisions. They also argued that the “baggage” of ancestral traits constrains future possibilities for profound change. The “New Synthesis”, a more recent convergence of paleontology, evolutionary biology, genome science, and embryology provides fertile ground for their critique. New approaches to genome analysis and gene categorization have shown that profound inter-species similarities underlie a generic and robust body plan upon which variant morphologies are built. Moreover, phenomenologically oriented approaches have recently revealed functional and organizational similarities among diverse genomes that are indicative of large and preserved gene regulatory behaviours: genomes appear to be organized into similar regulatory blocks irrespective of species. The implications of these recent discoveries suggest that emergent organizational and functional properties of genomes could impose big constraints upon morphological innovation. They might also explain some of the curious and profound examples of convergent evolution that puzzled Darwin