Analysing the elasticity difference tensor of general relativity

The elasticity difference tensor, used in [1] to describe elasticity properties of a continuous medium filling a space-time, is here analysed from the point of view of the space-time connection. Principal directions associated with this tensor are compared with eigendirections of the material metric. Examples concerning spherically symmetric and axially symmetric space-times are then presented.Comment: 17 page

Radial asymptotics of Lemaitre-Tolman-Bondi dust models

We examine the radial asymptotic behavior of spherically symmetric Lemaitre-Tolman-Bondi dust models by looking at their covariant scalars along radial rays, which are spacelike geodesics parametrized by proper length $\ell$, orthogonal to the 4-velocity and to the orbits of SO(3). By introducing quasi-local scalars defined as integral functions along the rays, we obtain a complete and covariant representation of the models, leading to an initial value parametrization in which all scalars can be given by scaling laws depending on two metric scale factors and two basic initial value functions. Considering regular "open" LTB models whose space slices allow for a diverging $\ell$, we provide the conditions on the radial coordinate so that its asymptotic limit corresponds to the limit as $\ell\to\infty$. The "asymptotic state" is then defined as this limit, together with asymptotic series expansion around it, evaluated for all metric functions, covariant scalars (local and quasi-local) and their fluctuations. By looking at different sets of initial conditions, we examine and classify the asymptotic states of parabolic, hyperbolic and open elliptic models admitting a symmetry center. We show that in the radial direction the models can be asymptotic to any one of the following spacetimes: FLRW dust cosmologies with zero or negative spatial curvature, sections of Minkowski flat space (including Milne's space), sections of the Schwarzschild--Kruskal manifold or self--similar dust solutions.Comment: 44 pages (including a long appendix), 3 figures, IOP LaTeX style. Typos corrected and an important reference added. Accepted for publication in General Relativity and Gravitatio

KinOath Kinship Archiver Version 1.4

This talk will introduce a new tool for Humanities research, in particular Ethnology, Linguistics, Law, History, but also Genetics and Archiving. This tool is KinOath Kinship Archiver which is an application for collecting and analysing kinship data. It is designed to be flexible and culturally nonspecific, which is important to prevent extraneous concepts being imposed onto the data being recorded. The kinship data can be linked to external resources such as archive data. Graphical representation of the data is a key feature, it produces publishable quality diagrams that can be exported to SVG, PDF and JPG formats. Data can be imported from GEDCOM, CSV and TIP files. Data can be exported into CSV format, with additional formats becoming available as plugins. KinOath provides very flexible data fields for each individual / entity recorded in the kinship data, this is combined with customisable relation types, customisable symbols and customisable kin types. This means, for example, that any number of genders and kinship relations can be defined and represented on a diagram. The most common format, GEDCOM (Family History Department, 1999), can be imported into KinOath. However this GEDCOM format exhibits cultural specificities because it has a predetermined set of kinship types, genders and initiation ceremonies. We know that there is a wider array of kinship types (e.g. suckling relations (Altorki, 1980)) and genders (e.g. the Māhū of Hawaiʻi (Matzner, 2001)). There are also initiation ceremonies beyond the Christian and Jewish ceremonies that are predefined in GEDCOM. However once this data is imported, all the flexibility of KinOath will be available. KinOath has project based diagrams and freeform diagrams. Freeform diagrams are like a quick sketch; while project diagrams each have a database of kinship data which can be shared across multiple diagrams. Project based diagrams also allow kin type string queries, such that individuals to be found based on their relations to others. Individuals in a project diagram can be duplicated and merged, which can be useful, for example, in correcting data, or merging multiple data sets where some individuals overlap. In freeform diagrams kin terms can be defined with kin type strings and shown on the diagram, organised in groups, imported and exported. In the future it will be possible to overlay these kin terms onto project diagrams. In order to perform statistical analysis, the kinship data for each project or freeform diagram can be exported for use in R or SPSS. This combined with queries based on kin types and other search parameters, provides great potential in the analysis of both the kin data and the archive data that has been recorded. The intended users of Kinoath are any researchers that collect data in a context of social relations. Kinship data is often not systematically included in the metadata of archives, however these kin relations provide a context that enriches that archived data. KinOath is in active development and new features are regularly being added. The plugin framework that KinOath shares with Arbil has made it possible for external developers to add features. The various versions and the manual are available at: http://tla.mpi.nl/tools/tlatools/kinoath/ REFERENCES Family History Department of The Church of Jesus Christ of Latterday Saints, 1999, THE GEDCOM STANDARD DRAFT Release 5.5.1 http://www.phpgedview.net/ged551¬5.pdf Matzner, Andrew. 2001. 'O au no keia: voices from Hawaii's Mahu and transgender communities. Bloomington, Indiana: Xlibris. Altorki, Soraya. 1980. MilkKinship in Arab Society: An Unexplored Problem in the Ethnography of Marriage. Ethnology 19(2): 233-24

Recent experimental results in sub- and near-barrier heavy ion fusion reactions

Recent advances obtained in the field of near and sub-barrier heavy-ion fusion reactions are reviewed. Emphasis is given to the results obtained in the last decade, and focus will be mainly on the experimental work performed concerning the influence of transfer channels on fusion cross sections and the hindrance phenomenon far below the barrier. Indeed, early data of sub-barrier fusion taught us that cross sections may strongly depend on the low-energy collective modes of the colliding nuclei, and, possibly, on couplings to transfer channels. The coupled-channels (CC) model has been quite successful in the interpretation of the experimental evidences. Fusion barrier distributions often yield the fingerprint of the relevant coupled channels. Recent results obtained by using radioactive beams are reported. At deep sub-barrier energies, the slope of the excitation function in a semi-logarithmic plot keeps increasing in many cases and standard CC calculations over-predict the cross sections. This was named a hindrance phenomenon, and its physical origin is still a matter of debate. Recent theoretical developments suggest that this effect, at least partially, may be a consequence of the Pauli exclusion principle. The hindrance may have far-reaching consequences in astrophysics where fusion of light systems determines stellar evolution during the carbon and oxygen burning stages, and yields important information for exotic reactions that take place in the inner crust of accreting neutron stars.Comment: 40 pages, 63 figures, review paper accepted for EPJ