Evaporation of large black holes in AdS: greybody factor and decay rate

We consider a massless, minimally coupled scalar field propagating through the geometry of a black 3-brane in an asymptotically $AdS_5 \times S^5$ space. The wave equation for modes traveling purely in the holographic direction reduces to a Heun equation and the corresponding greybody factor is obtained numerically. Approximations valid in the low- and high-frequency regimes are also obtained analytically. The greybody factor is then used to determine the rate of evaporation of these large black holes in the context of the evaporon model proposed in \cite{Rocha:2008fe}. This setting represents the evolution of a black hole under Hawking evaporation with a known CFT dual description and is therefore unitary. Information must then be preserved under this evaporation process.Comment: 20 pages, 2 figures; v2: added references, published versio

Seismic interpretation and generation of key depth structure surfaces within the Carboniferous and Devonian of the Orcadian Study Area, Quadrants 7-9, 11-15 and 19-21

This report details the rationale, methodology and results of a regional seismic interpretation of the 21CXRM Palaeozoic ‘Orcadian study area’, specifically the Inner Moray Firth and western Outer Moray Firth basins (Quadrants 11–15), the East Orkney Basin (Quadrant 13) and the Grampian High area (Quadrants 19–21). The aim of the interpretation was to create Two-Way Travel Time (TWTT) and depth maps that show the distribution of Palaeozoic basins and highs, and where possible interpret key Devono-Carboniferous surfaces and main structural elements in order to contribute a tectono-stratigraphic model of the Palaeozoic succession. Some 35,000 line kilometres of predominantly 2D seismic data have been interpreted and tied to key released wells in the study area. In total, 8 depth structure maps of key horizons have been produced for the pre-Permian succession. The maps do not cover the entire study area as it was not possible to interpret a specific seismic reflector everywhere due both to seismic resolution and also current day extents (as a result of non-deposition and/or erosion). These maps provide a key element to aid assessment of the petroleum systems of the Palaeozoic sequence within the study area. Where present, the surfaces with a grid spacing of 5000 m, give a regional view of the topography of the horizons, and comprise: Inner and Outer Moray Firth and East Orkney Basin area Base Zechstein; Top Firth Coal Formation; Top Eday Marl Formation; Top Orcadia Formation; Base Orcadia Formation; Top Struie Formation; Top Basement. The geological succession over the Grampian High area was such that only the following surfaces were generated: Base Zechstein; Base Carboniferous/ Top Devonian; Top Basement. The regional structure map of the area constructed for this report, and observations made from the seismic data, have been integrated with peer reviewed published information to describe a tectonic synthesis for the region (Leslie et. al., 2016). A new pre-Permian subcrop map is presented here that builds on existing publications (Smith, 1985; Marshall and Hewett 2003) and incorporates relevant new well penetrations since the previous maps were published. The well dataset has been either validated or re-interpreted before being integrated with the new seismic interpretation. The map extends the interpretation of the pre-Permian subcrop northwards from the published Central North Sea map (Arsenikos et al., 2015)

Organic geochemistry of Palaeozoic source rocks, central North Sea (CNS)

This report details a regional analysis of the source rock quality and potential of Palaeozoic rocks of the UK Central North Sea for the 21CXRM Palaeozoic project. The objective was to undertake a regional screening of all intervals to identify source rocks using new and legacy datasets of all Carboniferous and Devonian samples. In addition, a literature review (Appendix 1) summarises source and kerogen typing information from legacy reports. The background and stratigraphic nomenclature are given in Monaghan et al. (2016), details on individual well interpretations and stratigraphy are given in Kearsey et al. (2015). Geological context on the results of this work are included in basin modelling (Vincent, 2015) and were synthesised into a petroleum systems analysis in Monaghan et al. (2015). New and legacy Carboniferous and Devonian source rock geochemical data were examined per well using industry standard criteria to give an overview of the source rock quality, type (oil or gas prone) and maturity. The aims of this study were to classify the source rock quality of 33 wells, to examine if intervals were ‘gas-prone’ or ‘oil-prone’, and to ascertain the hydrocarbon generation stage of each well based on Rock-Eval pyrolysis, vitrinite reflectance (VR, where available) and total organic carbon (TOC) data. The term ‘gas prone’ was used to describe source rocks that have or could generate gas; ‘oil prone’ for source intervals that have or could generate oil. This study was a rapid screening exercise to identify intervals or areas of interest, and as such the data and inferences must be used concomitantly with other geological data to fully assess the source rock potential within the studied wells. It should be noted that the wells studied penetrate different parts of the geological succession and in many cases only small sections of the Devonian and Carboniferous interval. An initial sift through the wells with available geochemical data indicated that 33 wells had enough data to be usefully evaluated. Subsequently it was found that 8 of the 33 wells had incomplete, unreliable or otherwise poor source rock quality data sets and therefore were not analysed further; the reasons are detailed in this report. The remaining 25 wells selected for analysis were: 43/28-2, 26/07-1, 26/08-1, 36/13-1, 36/23-1, 38/16-1, 38/18-1, 39/07-1, 41/08-1, 42/10a-1, 42/10b-2ST, 42/09-1, 41/10-1, 42/10b-2, 41/15-1, 43/21-2, 41/01-1, 41/20-1, 41/14-1, 43/02-1, 43/17-2, 43/20b-2, 43/28-1, 43/28-2, 44/13-1, 44/16-1. Samples analysed from the majority of these wells were interpreted to be gas prone in the Carboniferous succession (Figure 1). 1. 41/10-1, 41/14-1 and 41/20-1 contained source rocks that were both gas window mature (e.g. VR >1.3) and can be regarded as excellent gas source. Strata in 43/17-2, 44/16-1 and 43/28-1 were also gas mature in all or parts of the section of interest, but with variable source rock quality. The six wells all had low S2 peaks: this may be due to either prior hydrocarbon generation and depletion or the initial presence of low amounts of non-inert kerogen. 2. 41/15-1, 42/10b-2 and 43/21-2 were also identified as possessing good gas-prone source rocks with elevated S2 values and also a high maturity attained by the source rocks. 41/01-1 was identified as a good for gas generation in the deeper section. 3. 26/07-1, 26/08-1, 36/13-1, 38/16-1, 39/07-1, 41/08-1, 42/10a-1, 42/10b-2ST, 42/09-1, 43/02-1, 43/20b-2, 43/28-2 and 44/13-1, contain good to excellent quality source rocks, but have not matured sufficiently to generate significant amount of gas, so these can be regarded as poor gas sources based on their current maturity. If present, in deeper basins some of these intervals will have generated significant quantities of gas

Manifestation of photonic band structure in small clusters of spherical particles

We study the formation of the photonic band structure in small clusters of dielectric spheres. The first signs of the band structure, an attribute of an infinite crystal, can appear for clusters of 5 particles. Density of resonant states of a cluster of 32 spheres may exhibit a well defined structure similar to the density of electromagnetic states of the infinite photonic crystal. The resonant mode structure of finite-size aggregates is shown to be insensitive to random displacements of particles off the perfect lattice positions as large as half-radius of the particle. The results were obtained by an efficient numerical method, which relates the density of resonant states to the the scattering coefficients of the electromagnetic scattering problem. Generalized multisphere Mie (GMM) solution was used to obtain scattering matrix elements. These results are important to miniature photonic crystal design as well as understanding of light localization in dense random media.Comment: 4 pages, 2 figure

Persistence of Various Alfalfa Populations in South Dakota Rangeland

Inclusion of alfalfa (Medicago sativa L.) in grasslands has long been valued to increase forage production and quality. Persistence of alfalfa in semiarid rangeland has generally been poor when non‐adapted and/or conventional hay‐type cultivars are utilized, however. Demand exists for alfalfa cultivars that establish readily and persist, particularly under grazing, in semiarid rangelands. A wild population of predominantly yellow‐flowered alfalfa (Medicago sativa subsp. falcata) was found growing and reproducing naturally in the Grand River National Grassland in northwestern South Dakota. This predominantly falcata alfalfa therefore demonstrates persistence in this semiarid environment. We initiated a study in May 2006 at the SDSU Antelope Livestock & Range Field Station near Buffalo, SD to evaluate persistence and vigor of eleven alfalfa populations transplanted into mixed‐grass prairie. Populations consisted of four predominantly falcata experimental populations (three are naturally selected and locally adapted; one is artificially selected), one pure falcata experimental population, one pure falcata cultivar, two pasture‐type cultivars, and three conventional hay‐type cultivars. Greenhouse grown seedlings were transplanted on 1 m‐centers within three exclosures (35 m X 35 m) divided into two sections; one exposed to grazing, the other protected from grazing. Grazing by cattle was initiated in August 2007. During the 2008 and 2009 growing seasons, intense grazing of alfalfa plants and associated vegetation occurred monthly for 1‐2 days. Survival, height, and canopy volume of grazed and protected alfalfa plants were measured before each grazing event. Despite a harsh winter with persistent ice cover, data from May 2009 revealed that falcata‐based populations had the highest survival under grazing (mean survival = 36%). Pasture‐type cultivars and conventional hay‐type cultivars experienced substantial mortality losses under grazing (mean survival = 8%). Low mortality and high vigor of all protected plant populations indicates that grazing weakened the grazed plants, greatly increasing the risk of winterkill and winter injury. These findings reveal that environmental adaptation, in addition to a degree of grazing tolerance, is necessary for persistence under grazing in this semiarid region. Populations that exhibit high persistence under both grazing and severe winter conditions offer great potential for being utilized in the northern Great Plains

Plastination: a novel approach to cadavar scarcity in Nigeria

Cadaveric dissection has always been an integral part of medical education being used for teaching Anatomy, Surgery, Pathology, Radiology, Medical and Biomedical Research in Nigeria higher institutions of learning. However, it is undeniable that Nigeria Universities had been facing a lot of challenges in acquiring cadavers. In view of this scarcity of bodies, organs and tissues for studies, teaching and research, newer techniques of preserving biological tissues for long duration such as plastination is important. Thus, this review elaborates and identifies problems in cadaver acquisition in Nigeria, suggests better preservative technique of cadaver and identifies possible limitations to the practice of the suggested technique and proper possible solutions to the limitations.Keywords: Plastination, Cadaver, Anatomy, Preservativ

Relativistic many-body calculations of electric-dipole matrix elements, lifetimes and polarizabilities in rubidium

Electric-dipole matrix elements for ns-n'p, nd-n'p, and 6d-4f transitions in Rb are calculated using a relativistic all-order method. A third-order calculation is also carried out for these matrix elements to evaluate the importance of the high-order many-body perturbation theory contributions. The all-order matrix elements are used to evaluate lifetimes of ns and np levels with n=6, 7, 8 and nd levels with n=4, 5, 6 for comparison with experiment and to provide benchmark values for these lifetimes. The dynamic polarizabilities are calculated for ns states of rubidium. The resulting lifetime and polarizability values are compared with available theory and experiment.Comment: 8 pages, 2 figure

Hyperfine splitting in heavy ions with the nuclear magnetization distribution determined from experiments on muonic atoms

The hyperfine splitting in hydrogenlike $^{209}$Bi, $^{203}$Tl, and $^{205}$Tl is calculated with the nuclear magnetization determined from experimental data on the hyperfine splitting in the corresponding muonic atoms. The single-particle and configuration-mixing nuclear models are considered. The QED corrections are taken into account for both electronic and muonic atoms. The obtained results are compared with other calculations and with experiment.Comment: 8 pages, 5 tables, accepted for publication in Nuclear Instruments and Methods in Physics Research

Cremmer-Gervais r-matrices and the Cherednik Algebras of type GL2

We give an intepretation of the Cremmer-Gervais r-matrices for sl(n) in terms of actions of elements in the rational and trigonometric Cherednik algebras of type GL2 on certain subspaces of their polynomial representations. This is used to compute the nilpotency index of the Jordanian r-matrices, thus answering a question of Gerstenhaber and Giaquinto. We also give an interpretation of the Cremmer-Gervais quantization in terms of the corresponding double affine Hecke algebra.Comment: 6 page

Mesh update techniques for free-surface flow solvers using spectral element method

This paper presents a novel mesh-update technique for unsteady free-surface Newtonian flows using spectral element method and relying on the arbitrary Lagrangian--Eulerian kinematic description for moving the grid. Selected results showing compatibility of this mesh-update technique with spectral element method are given