Quantum dynamics of particles in a discrete two-branes world model: Can matter particles exchange occur between branes?

In a recent paper, a model for describing the quantum dynamics of massive particles in a non-commutative two-sheeted spacetime was proposed. This model considers a universe made with two spacetime sheets embedded in a 5D bulk where the fifth dimension is restricted to only two points. It was shown that this construction has several important consequences for the quantum dynamics of massive particles. Most notably, it was demonstrated that a coupling arises between the two sheets allowing matter exchange in presence of intense magnetic vector potentials. In this paper, we show that non-commutative geometry is not absolutely necessary to obtain such a result since a more traditional approach allows one to reach a similar conclusion. The fact that two different approaches provide similar results suggests that standard matter exchange between branes might finally occur contrary to conventional belief.Comment: 11 pages, no figures. Final version. Published in Acta Physica Polonica

Plausible "faster-than-light" displacements in a two-sheeted spacetime

In this paper, we explore the implications of a two-point discretization of an extra-dimension in a five-dimensional quantum setup. We adopt a pragmatic attitude by considering the dynamics of spin-half particles through the simplest possible extension of the existing Dirac and Pauli equations. It is shown that the benefit of this approach is to predict new physical phenomena while maintaining the number of constitutive hypothesis at minimum. As the most striking feature of the model, we demonstrate the possibility of fermionic matter oscillations between the two four-dimensional sections and hyper-fast displacements in case of asymmetric warping (without conflicting special relativity). This result, similar to previous reported ones in brane-world theories, is completely original as it is derived by using quantum mechanics only without recourse to general relativity and bulk geodesics calculation. The model allows causal contact between normally disconnected regions. If it proves to be physically founded, its practical aspects could have deep implications for the search of extra-dimensions.Comment: 17 pages, 1 figure. Final version. Accepted for publication in Phys. Rev.

Understanding business strategies of networked value constellations using goal- and value modeling

In goal-oriented requirements engineering (GORE), one usually proceeds from a goal analysis to a requirements specification, usually of IT systems. In contrast, we consider the use of GORE for the design of IT-enabled value constellations, which are collections of enterprises that jointly satisfy a consumer need using information technology. The requirements analysis needed to do such a crossorganizational design not only consists of a goal analysis, in which the relevant strategic goals of the participating companies are aligned, but also of a value analysis, in which the commercial sustainability of the constellation is explored. In this paper we investigate the relation between strategic goal- and value modeling. We use theories about business strategy such as those by Porter to identify strategic goals of a value constellation, and operationalize these goals using value models. We show how value modeling allows us to find more detailed goals, and to analyze conflicts among goals

Definition and Validation of a Business IT Alignment Method for Enterprise Governance Improvement in the Context of Processes Based Organizations

These days, it is remarkable to note the growing of interest in professional responsibility. Specifically, the responsibility a person commits to when he or she performs a task. Based on a review of research currently performed in the field of policy (from corporate to technical ones), we observe that the perception of responsibility has often been limited to a combination of rights and obligations. In addition, we are seeing a re-emergence in business (for example, in the financial sector) of a belief that business ethics foundation can be improved and that a renewed focus in this area would help to prevent future breakdowns in the system. With regard to improving business/IT alignment and corporate ICT governance, it becomes increasingly important to define a commonly accepted personal responsibility model that embodies important and well-known concepts like accountability, capability and commitment. Moreover, because responsibility constitutes a fundamental notion of management theory, it is likewise identified as a meaningful bridge toward organizational artifacts. Exploiting process-based approach to define policy seems to offer new research opportunities since process-based organization becomes a continuous widely spread structure.ICT Governance, Responsibility model, Capability, Accountability, Commitment.

Measuring correlations of cold atom systems using multiple quantum probes

We present a non-destructive method to probe a complex quantum system using multiple impurity atoms as quantum probes. Our protocol provides access to different equilibrium properties of the system by changing its coupling to the probes. In particular, we show that measurements with two probes reveal the system's non-local two-point density correlations, for probe-system contact interactions. We illustrate our findings with analytic and numerical calculations for the Bose-Hubbard model in the weakly and strongly-interacting regimes, under conditions relevant to ongoing experiments in cold atom systems.Comment: 11 pages, 6 figures. v2: enhanced discussion in light of other correlation measurement methods available; matches published versio

Letter to Diana Osbaldiston regarding the Southeastern Law Librarian, July 22, 1988

A letter from Michael Petit to Diana Osbaldiston providing deadlines for the Southeastern Law Librarian

Genetics and functions of the SARS coronavirus spike protein

The SARS-Coronavirus (SARS-CoV) is the etiological agent of the severe acute respiratory syndrome (SARS). The SARS-CoV spike (S) glycoprotein mediates membrane fusion events during virus entry and virus-induced cell-to-cell fusion. Investigations, described herein, have focused on the genetic manipulation of the SARS-CoV S glycoprotein in order to delineate functional domains within the protein. This was accomplished by incorporating single point mutations, cluster-to-lysine and cluster-to-alanine mutations, as well as carboxyl terminal truncations into the protein and investigating these mutants in transient expression experiments. Mutagenesis of either the coiled-coil domain of the S glycoprotein amino terminal heptad repeat, the predicted fusion peptide, or adjacent but distinct regions, severely compromised S-mediated cell-to-cell fusion, while intracellular transport and cell-surface expression were not adversely affected. Surprisingly, a carboxyl terminal truncation of 17 amino acids substantially increased S glycoprotein-mediated cell-to-cell fusion suggesting that the terminal 17 amino acids regulate the S fusogenic properties. In contrast, truncation of 26 or 39 amino acids eliminating either one or both of the two endodomain cysteine-rich motifs, respectively, inhibited cell fusion in comparison to the wild-type S. The cysteine rich domains were further studied by constructing cysteine cluster to alanine mutants in order to ascertain their importance in the function of the protein. Results showed that the two cysteine clusters proximal to the transmembrane region were vital in the functioning of the spike protein in mediating cell-to-cell fusion. Mutagenesis of the acidic amino acid cluster in the carboxyl terminus of the S glycoprotein as well as modification of a predicted phosphorylation site within the acidic cluster revealed that this amino acid motif may play a functional role in the retention of S at cell-surfaces. A panel of truncations for Bovine Coronavirus (BCoV) S was also constructed and compared to truncations made for the SARS-CoV S glycoprotein. It was found that the two sets of truncations had very little comparable effects on protein function when compared to one another. This genetic analysis reveals that the SARS-CoV S glycoprotein contains extracellular domains that regulate cell fusion as well as distinct endodomains that function in intracellular transport, cell-surface expression and cell fusion