Energy and Momentum Distributions of Kantowski and Sachs Space-time

We use the Einstein, Bergmann-Thomson, Landau-Lifshitz and Papapetrou energy-momentum complexes to calculate the energy and momentum distributions of Kantowski and Sachs space-time. We show that the Einstein and Bergmann-Thomson definitions furnish a consistent result for the energy distribution, but the definition of Landau-Lifshitz do not agree with them. We show that a signature switch should affect about everything including energy distribution in the case of Einstein and Papapetrou prescriptions but not in Bergmann-Thomson and Landau-Lifshitz prescriptions.Comment: 12 page

Constructing multiple unique input/output sequences using metaheuristic optimisation techniques

Multiple unique input/output sequences (UIOs) are often used to generate robust and compact test sequences in finite state machine (FSM) based testing. However, computing UIOs is NP-hard. Metaheuristic optimisation techniques (MOTs) such as genetic algorithms (GAs) and simulated annealing (SA) are effective in providing good solutions for some NP-hard problems. In the paper, the authors investigate the construction of UIOs by using MOTs. They define a fitness function to guide the search for potential UIOs and use sharing techniques to encourage MOTs to locate UIOs that are calculated as local optima in a search domain. They also compare the performance of GA and SA for UIO construction. Experimental results suggest that, after using a sharing technique, both GA and SA can find a majority of UIOs from the models under test

FISH mapping and molecular organization of the major repetitive sequences of tomato

This paper presents a bird's-eye view of the major repeats and chromatin types of tomato. Using fluorescence in-situ hybridization (FISH) with Cot-1, Cot-10 and Cot-100 DNA as probes we mapped repetitive sequences of different complexity on pachytene complements. Cot-100 was found to cover all heterochromatin regions, and could be used to identify repeat-rich clones in BAC filter hybridization. Next we established the chromosomal locations of the tandem and dispersed repeats with respect to euchromatin, nucleolar organizer regions (NORs), heterochromatin, and centromeres. The tomato genomic repeats TGRII and TGRIII appeared to be major components of the pericentromeres, whereas the newly discovered TGRIV repeat was found mainly in the structural centromeres. The highly methylated NOR of chromosome 2 is rich in [GACA](4), a microsatellite that also forms part of the pericentromeres, together with [GA](8), [GATA](4) and Ty1-copia. Based on the morphology of pachytene chromosomes and the distribution of repeats studied so far, we now propose six different chromatin classes for tomato: (1) euchromatin, (2) chromomeres, (3) distal heterochromatin and interstitial heterochromatic knobs, (4) pericentromere heterochromatin, (5) functional centromere heterochromatin and (6) nucleolar organizer regio

A Uq(gl^(2∣2))1U_q\bigl(\hat{gl}(2|2)\bigr)_1-Vertex Model: Creation Algebras and Quasi-Particles I

The infinite configuration space of an integrable vertex model based on $U_q\bigl(\hat{gl}(2|2)\bigr)_1$ is studied at $q=0$. Allowing four particular boundary conditions, the infinite configurations are mapped onto the semi-standard supertableaux of pairs of infinite border strips. By means of this map, a weight-preserving one-to-one correspondence between the infinite configurations and the normal forms of a pair of creation algebras is established for one boundary condition. A pair of type-II vertex operators associated with an infinite-dimensional $U_q\bigl(gl(2|2)\bigr)$-module $\mathring V$ and its dual $\mathring V^*$ is introduced. Their existence is conjectured relying on a free boson realization. The realization allows to determine the commutation relation satisfied by two vertex operators related to the same $U_q\bigl(gl(2|2)\bigr)$-module. Explicit expressions are provided for the relevant R-matrix elements. The formal $q\to0$ limit of these commutation relations leads to the defining relations of the creation algebras. Based on these findings it is conjectured that the type II vertex operators associated with $\mathring V$ and $\mathring V^*$ give rise to part of the eigenstates of the row-to-row transfer matrix of the model. A partial discussion of the R-matrix elements introduced on $\mathring V\otimes \mathring V^*$ is given.Comment: 45 pages, 5 figures, to appear in Nucl. Phys.

On-chip integrated amplifiers and lasers utilizing rare-earth-ion activation

This contribution reviews our recent results on rare-earth-ion-doped integrated amplifiers and lasers. We have concentrated our efforts on complex-doped polymers, amorphous Al2O3, and crystalline potassium double tungstates

The rare decays B --> K(*) anti-K(*) and R-parity violating supersymmetry

We study the branching ratios, the direct CP asymmetries in $B\to K^{(*)}\bar{K}^{(*)}$ decays and the polarization fractions of $B\to K^{*}\bar{K}^{*}$ decays by employing the QCD factorization in the minimal supersymmetric standard model with R-parity violation. We derive the new upper bounds on the relevant R-parity violating couplings from the latest experimental data of $B\to K^{(*)}\bar{K}^{(*)}$, and some of these constraints are stronger than the existing bounds. Using the constrained parameter spaces, we predict the R-parity violating effects on the other quantities in $B\to K^{(*)}\bar{K}^{(*)}$ decays which have not been measured yet. We find that the R-parity violating effects on the branching ratios and the direct $CP$ asymmetries could be large, nevertheless their effects on the longitudinal polarizations of $B\to K^{*}\bar{K}^{*}$ decays are small. Near future experiments can test these predictions and shrink the parameter spaces.Comment: 31 pages with 10 figure

Gait parameter estimation from a miniaturized ear-worn sensor using singular spectrum analysis and longest common subsequence

This paper presents a new approach to gait analysis and parameter estimation from a single miniaturised earworn sensor embedded with a triaxial accelerometer. Singular spectrum analysis (SSA) combined with the longest common subsequence (LCSS) algorithm has been used as a basis for gait parameter estimation. It incorporates information from all axes of the accelerometer to estimate parameters including swing, stance and stride times. Rather than only using local features of the raw signals, the periodicity of the signals is also taken into account. The hypotheses tested by this study include: 1) how accurate is the ear-worn sensor in terms of gait parameter extraction compared to the use of an instrumented treadmill; 2) does the ear-worn sensor provide a feasible option for assessment and quantification of gait pattern changes. Key gait events for normal subjects such as heel contact and toe off are validated with a high-speed camera, as well as a force-plate instrumented treadmill. Ten healthy adults walked for 20 minutes on a treadmill with an increasing incline of 2% every 2 minutes. The upper and lower limits of the absolute errors using 95% confidence intervals for swing, stance and stride times were obtained as 35.5±3.99ms, 36.9 ± 3.84ms, and 17.9 ± 2.29ms, respectively

Microstructural evolution in cast Haynes 282 for applications in advanced power plants

There is a worldwide drive to increase the efficiency of power plants in order to reduce the amount of fossil fuel consumed and associated CO2 emissions. Raising the operating temperature and pressure can improve the thermal efficiency, however, this necessitate the use of materials which have high temperature performance. Steels are currently used at temperature up to 600°C with the efficiency of 38-40 %. Advanced Ultra Supercritical (A-USC) design plans power plants to operate at steam temperatures of 700°C and pressure up to 35 MPa with a lifetime of at least 100 000 hours. Ni-base superalloys are leading materials due to their significant strength and creep resistance. Haynes 282 is one possible candidate to meet the A-USC conditions for turbine engines. This alloy is a γ′ precipitation strengthened material and exhibits very good creep properties and thermal stability. The alloy examined in this research was produced by sand casting, and therefore the aim of this research is to investigate the microstructural evolution in large scale cast components. The alloy has been examined in both the as-cast condition and as a function of a range of different pre-service heat treatments. The microstructural changes during different heat treatments have been fully identified and quantified. The results have also been compared with predictions from thermodynamic equilibrium calculations using a Ni alloy database. It has been found that variations in the heat treatment conditions can have a significant effect on microstructural development and hence, potentially, the mechanical properties of Haynes 282 alloy

Memory usage verification using Hip/Sleek.

Embedded systems often come with constrained memory footprints. It is therefore essential to ensure that software running on such platforms fulfils memory usage specifications at compile-time, to prevent memory-related software failure after deployment. Previous proposals on memory usage verification are not satisfactory as they usually can only handle restricted subsets of programs, especially when shared mutable data structures are involved. In this paper, we propose a simple but novel solution. We instrument programs with explicit memory operations so that memory usage verification can be done along with the verification of other properties, using an automated verification system Hip/Sleek developed recently by Chin et al.[10,19]. The instrumentation can be done automatically and is proven sound with respect to an underlying semantics. One immediate benefit is that we do not need to develop from scratch a specific system for memory usage verification. Another benefit is that we can verify more programs, especially those involving shared mutable data structures, which previous systems failed to handle, as evidenced by our experimental results

Excited State TBA for the ϕ2,1\phi_{2,1} perturbed M3,5M_{3,5} model

We examine some excited state energies in the non-unitary integrable quantum field theory obtained from the perturbation of the minimal conformal field theory model $M_{3,5}$ by its operator $\phi_{2,1}$. Using the correspondence of this IQFT to the scaling limit of the dilute $A_2$ lattice model (in a particular regime) we derive the functional equations for the QFT commuting transfer matrices. These functional equations can be transformed to a closed set of TBA-like integral equations which determine the excited state energies in the finite-size system. In particular, we explicitly construct these equations for the ground state and two lowest excited states. Numerical results for the associated energy gaps are compared with those obtained by the truncated conformal space approach (TCSA).Comment: LaTeX, 32 pages, 6 figure