The dating and provenance of glass artefacts excavated from the ancient city of Tall Zirā‛a, Jordan

The first deliberate manufacture of glass occurs in the sixteenth century BC, although the origin of the material is still a focus of debate; Egypt or Mesopotamia being the most likely innovator. The conventional approach is that glass technology first developed in Mesopotamia (Barag, 1970, p131-4; Moorey, 1994, p192; Shortland et al., 2017) and that the subsequent transfer to Egypt could be ascribed to tribute associated with the successful military campaigns in the Levant by the Egyptian king, Tuthmosis III (1479-1425 BC). Although there is textual and iconographic evidence for the production, supply and transport of glass between Egypt, its vassal Levantine states and Mesopotamia, it is very rare to find Egyptian glass in Mesopotamia or vice versa (Walton et al. 2009). The exceptions to date are two green glass rods found in Amarna, Egypt, which have trace element compositions consistent with Mesopotamian glass, and a collection of blue glass beads and a scarab recovered from a tomb in Gurob, Egypt, which also showed compositional consistency with glasses of known Mesopotamian origin (Varberg et al., 2016; Kemp, McDonald, A and Shortland, 2017; Kemp et al., 201

Raman scattering in C_{60} and C_{48}N_{12} aza-fullerene: First-principles study

We carry out large scale {\sl ab initio} calculations of Raman scattering activities and Raman-active frequencies (RAFs) in ${\rm C}_{48}{\rm N}_{12}$ aza-fullerene. The results are compared with those of ${\rm C}_{60}$. Twenty-nine non-degenerate polarized and 29 doubly-degenerate unpolarized RAFs are predicted for ${\rm C}_{48}{\rm N}_{12}$. The RAF of the strongest Raman signal in the low- and high-frequency regions and the lowest and highest RAFs for ${\rm C}_{48}{\rm N}_{12}$ are almost the same as those of ${\rm C}_{60}$. The study of ${\rm C}_{60}$ reveals the importance of electron correlations and the choice of basis sets in the {\sl ab initio} calculations. Our best calculated results for ${\rm C}_{60}$ with the B3LYP hybrid density functional theory are in excellent agreement with experiment and demonstrate the desirable efficiency and accuracy of this theory for obtaining quantitative information on the vibrational properties of these molecules.Comment: submitted to Phys.Rev.

A mathematical and computational review of Hartree-Fock SCF methods in Quantum Chemistry

We present here a review of the fundamental topics of Hartree-Fock theory in Quantum Chemistry. From the molecular Hamiltonian, using and discussing the Born-Oppenheimer approximation, we arrive to the Hartree and Hartree-Fock equations for the electronic problem. Special emphasis is placed in the most relevant mathematical aspects of the theoretical derivation of the final equations, as well as in the results regarding the existence and uniqueness of their solutions. All Hartree-Fock versions with different spin restrictions are systematically extracted from the general case, thus providing a unifying framework. Then, the discretization of the one-electron orbitals space is reviewed and the Roothaan-Hall formalism introduced. This leads to a exposition of the basic underlying concepts related to the construction and selection of Gaussian basis sets, focusing in algorithmic efficiency issues. Finally, we close the review with a section in which the most relevant modern developments (specially those related to the design of linear-scaling methods) are commented and linked to the issues discussed. The whole work is intentionally introductory and rather self-contained, so that it may be useful for non experts that aim to use quantum chemical methods in interdisciplinary applications. Moreover, much material that is found scattered in the literature has been put together here to facilitate comprehension and to serve as a handy reference.Comment: 64 pages, 3 figures, tMPH2e.cls style file, doublesp, mathbbol and subeqn package

Agricultural, architectural and archaeological evidence for the role and ecological adaptation of a scattered mountain oasis in Oman

The original publication is available at www.elsevier.co

Evaluating the Effects of Different Requirements Representations on Writing Test Cases

Context and MotivationOne must test a system to ensure that the requirements are met, thus, tests are often derived manually from requirements. However, requirements representations are diverse; from traditional IEEE-style text, to models, to agile user stories, the RE community of research and practice has explored various ways to capture requirements. Question/problemBut, do these different representations influence the quality or coverage of test suites? The state-of-the-art does not provide insights on whether or not the representation of requirements has an impact on the coverage, quality, or size of the resulting test suite. ResultsIn this paper, we report on a family of three experiment replications conducted with 148 students which examines the effect of different requirements representations on test creation. We find that, in general, the different requirements representations have no statistically significant impact on the number of derived tests, but specific affordances of the representation effect test quality, e.g., traditional textual requirements make it easier to derive less abstract tests, whereas goal models yield less inconsistent test purpose descriptions. ContributionOur findings give insights on the effects of requirements representation on test derivation for novice testers. Our work is limited in the use of students