Total Mass-Momentum of Arbitrary Initial-Data Sets in General Relativity

For an asymptotically flat initial-data set in general relativity, the total mass-momentum may be interpreted as a Hermitian quadratic form on the complex, two-dimensional vector space of ``asymptotic spinors''. We obtain a generalization to an arbitrary initial-data set. The mass-momentum is retained as a Hermitian quadratic form, but the space of ``asymptotic spinors'' on which it is a function is modified. Indeed, the dimension of this space may range from zero to infinity, depending on the initial data. There is given a variety of examples and general properties of this generalized mass-momentum.Comment: 25 pages, LaTe

Response to Comment on “Characterization of Excess Electrons in Water-Cluster Anions by Quantum Simulations”

In response to the Comment by Neumark and co-workers, we reiterate that the conclusions of the title Report are based on identifiable characteristic trends in several observables with cluster size. The numerical comparison between simulated and experimental vertical detachment energies emphasized in the Comment reflect quantitative limitations of our atomistic model, but, in our opinion, do not undermine these conclusions

Characterization of Excess Electrons in Water Cluster Anions via Quantum Simulations

Water cluster anions can serve as a bridge to understand the transition from gaseous species to the bulk hydrated electron. However, debate continues regarding how the excess electron is bound in H2On- , as an interior, bulk-like, or surface electronic state. To address the uncertainty, the properties of H2On- clusters with 20 to 200 water molecules have been evaluated by mixed quantum-classical simulations. The theory reproduces every observed energetic, spectral, and structural trend with n that is seen in experimental photoelectron and optical absorption spectra. More importantly, surface states and interior states each manifest a unique signature in the simulation data. The results strongly support assignment of surface bound electronic states to the water cluster anions in published experimental studies thus far

Mean Reversion of Balance of Payments¡GEvidence from Sequential Trend Break Unit Root Tests

We analyze the G7 countries data set of real balance of payments series. The unit root tests with an endogenously determined break date in the trend function proposed by Zivot and Andrews (1992) is employed to characterize the balance of payments series. The empirical results show that allowing for a break in the trend function could alter the outcome of the standard unit root tests for some series.Balance of payments

Evaluating the quality of undergraduate hospitality, tourism and leisure programmes

In this study, an instrument for measuring the quality of undergraduate programmes in hospitality, tourism and leisure (HTLP) was developed and empirically cross-validated. The study considered how total quality management (TQM) and context-input-process-product (CIPP) perspectives could be integrated to develop the framework, using documentary analysis, focus groups and content validity. Survey responses from 430 full-time teachers were used to verify the instrument for HTLP (IHTLP) via exploratory and confirmatory factor analysis, and six standards, 12 dimensions and 63 indicators were identified. The six standards, in terms of relative importance, are curriculum and instruction; faculty; strategic planning; administrative management; student achievements; and resources. The implications for HTLP are also discussed

An Enumerative Perspective on Connectivity

Connectivity (or equivalently, unweighted maximum flow) is an important measure in graph theory and combinatorial optimization. Given a graph $G$ with vertices $s$ and $t$, the connectivity $\lambda(s,t)$ from $s$ to $t$ is defined to be the maximum number of edge-disjoint paths from $s$ to $t$ in $G$. Much research has gone into designing fast algorithms for computing connectivities in graphs. Previous work showed that it is possible to compute connectivities for all pairs of vertices in directed graphs with $m$ edges in $\tilde{O}(m^\omega)$ time [Chueng, Lau, and Leung, FOCS 2011], where $\omega \in [2,2.3716)$ is the exponent of matrix multiplication. For the related problem of computing "small connectivities," it was recently shown that for any positive integer $k$, we can compute $\min(k,\lambda(s,t))$ for all pairs of vertices $(s,t)$ in a directed graph with $n$ nodes in $\tilde{O}((kn)^\omega)$ time [Akmal and Jin, ICALP 2023]. In this paper, we present an alternate exposition of these $\tilde{O}(m^\omega)$ and $\tilde{O}((kn)^\omega)$ time algorithms, with simpler proofs of correctness. Earlier proofs were somewhat indirect, introducing an elegant but ad hoc "flow vector framework" for showing correctness of these algorithms. In contrast, we observe that these algorithms for computing exact and small connectivity values can be interpreted as testing whether certain generating functions enumerating families of edge-disjoint paths are nonzero. This new perspective yields more transparent proofs, and ties the approach for these problems more closely to the literature surrounding algebraic graph algorithms

An Automated Testing Approach For Pxi Chassis Software Driver

PXI chassis is a multi-vendor interoperable device, it can interconnect with many chassis, module and computer type. To make sure the device driver is able to function in specific configuration it must go through a series of testing. The complexity of PXI software testing has increased when it need to cover multiple configuration for single driver. Majority of the automated test system will execute test without have a mechanism to verify the test environment. The current trend of automated software test only execute on single test configuration, to improve the PXI chassis IVI driver test duration a test software with the capability of execute multi test configuration is developed. In order to develop this tool, a server-client concept is adopted. The advantage of server-client is to centralize the testing when multiple test system perform test at same time. The software tool client will start once completely boot in to operating system, the test system will connect to server and wait for further action from server. When server detected incoming client connection it will automatically verify and fix the testing environment, if the client fulfilled the test suite requirement it will start execute test. All clients test summary result will be feedbacked to server. The results show an average of 17.1% test duration reduction on the planned test configuration when the automated software tool applied on testing. Besides that the results suggest that execute the test on higher controller hardware performance can reduce the test duration as well