New parametrization for differences between plasma kinetic codes

Validation and verification of plasma kinetics codes requires the development of quantitative methods and techniques for code comparisons. We describe two parameters that can be used for characterization of differences between such codes. It is shown that these parameters, which are determined from the most general results of kinetic codes, can provide important information on the differences between the basic rate coefficients employed. Application of this method is illustrated by comparisons of some results from the 3rd NLTE Code Comparison Workshop for carbon, germanium, and gold plasmas.Comment: Submitted to High Energy Density Physics, 12 pages, 2 figure

Generating Sentences Using a Dynamic Canvas

We introduce the Attentive Unsupervised Text (W)riter (AUTR), which is a word level generative model for natural language. It uses a recurrent neural network with a dynamic attention and canvas memory mechanism to iteratively construct sentences. By viewing the state of the memory at intermediate stages and where the model is placing its attention, we gain insight into how it constructs sentences. We demonstrate that AUTR learns a meaningful latent representation for each sentence, and achieves competitive log-likelihood lower bounds whilst being computationally efficient. It is effective at generating and reconstructing sentences, as well as imputing missing words.Comment: AAAI 201

Measuring viscoelastic properties using compliant systems

An analysis of a novel indentation model has been implemented to obtain master curves describing the optimal experimental parameters necessary to achieve the highest possible accuracy in the determination of viscoelastic properties of soft materials. The indentation model is a rigid indenter driven by a compliant measurement system, such as an atomic force microscope or optical tweezers, into a viscoelastic half space. The viscoelastic material is described as a multiple relaxation Prony series. The results have been extended via an application of a viscoelastic equivalence principle to other physical models such as poroelasticity. Optimisation of the indentation parameters has been conducted over many orders of magnitude of the velocity, viscoelastic moduli, spring stiffness, relaxation times and the duration of indentation resulting in a characteristic master curve. It is shown that using sub-optimal conditions gives the appearance of a more elastic material than is actually the case. For a two term Prony series the ideal ramp duration was found to be approximately one eighth of the relaxation. Also the ideal ramp duration for a three term Prony series was determined and shown to guarantee distinct relaxation times under specific conditions

A model to distribute mark-up amongst quotation component item

The outline of a proposed new unbalanced bidding model is discussed. Background is provided as regards the role of item price loading, otherwise known as unbalanced bidding. Three types of loading are described, namely those of ‘front-end loading’, ‘back-end loading’ and ‘quantity error exploitation’ (otherwise known as ‘individual rate loading’). It is proposed that one single mathematical model could embrace all three of the above types and that the aspect of risk may be addressed partially by means of using the quadratic programming techniques employed within the field of Modern Portfolio Theory. MPT is a field pioneered by Markowitz in 1959 and was developed to identify optimum portfolios of investments, typically equities. It is hypothesized that MPT presents a basis by which to distinguish Efficient Item Pricing combinations from inefficient ones and thereby provide a scientific tool by which rational contractors may optimally price a project’s items. A brief history of unbalanced bidding describes the field that was pioneered in the 1960’s by Marvin Gates and Robert Stark, as well as the subsequent contributions by the leading researchers in the field.unbalanced bidding, bidding models, item price loading, modern portfolio theory, construction industry, mathematical models, bidding strategies

Redshifts of galaxies close to bright QSO lines of sight

To expand the known number of low-redshift galaxies which lie close to bright ($V < 17.2$) QSO lines of sight, we have identified 24 galaxies within 11 arcmins of nine QSOs which have been observed with the Hubble Space Telescope (HST). Galaxies are found between redshifts of $0.0114-0.145$ and lie between $39-749$ $h^{-1}$ kpc from QSO sightlines. Knowing the redshifts of these galaxies has already proved important in understanding results from HST programmes designed to search for UV absorption lines from low-redshift galaxies, and will enable future observations to probe the halos of these galaxies in detail.Comment: MNRAS in press. 9 pages LaTeX using MNRAS sty. Postscript figures are excluded due to large size. Paper with figures can be obtained from http://www.roe.ac.uk/research/bowen1.ps.

Interstellar Mg II and C IV absorption by 1 1/2 galaxies along the sightline to MrK 205

The first results of our HST survey designed to search for Mg 2 and C 4 absorption lines from the disks and halos of low-redshift galaxies using background QSO's and supernovae as probes are presented. Our survey utilizes the high resolution of the Goddard High Resolution Spectrograph enabling us to calculate the column densities and doppler parameters of individual components within an absorption complex, and hence determine the physical conditions of the absorbing gas. Observing the complexity of the absorption line profiles i.e., the velocity distribution and total velocity extent of the constituent components, offers an important description of the kinematics of the absorbing gas, and hence an understanding of its origin. Focus is on one sight line in particular, that towards Mrk 205, which passes 3-5 kpc from the intervening galaxy NGC 4319. Mg 2 and C 4 absorption from both local Milky Way halo gas and from NGC 4319 is detected

The Detection of Lyman-alpha Absorption from Nine Nearby Galaxies

We have used STIS aboard HST to search for Lyman-alpha (Lya) absorption in the outer regions of nine nearby (cz<6000 km/s) galaxies using background QSOs and AGN as probes. The foreground galaxies are intercepted between 26 and 199 h-1 kpc from their centers, and in all cases we detect Lya within +/-500 km/s of the galaxies' systemic velocities. The intervening galaxies have a wide range of luminosities, from M_B = -17.1 to -20.0, and reside in various environments: half the galaxies are relatively isolated, the remainder form parts of groups or clusters of varying richness. The equivalent widths of the Lya lines range from 0.08 - 0.68 A and, with the notable exception of absorption from one pair, crudely correlate with sightline separation in a way consistent with previously published data, though the column densities derived from the lines do not. The lack of correlation between line strength and galaxy luminosity or, in particular, the environment of the galaxy, suggests that the absorption is not related to any individual galaxy, but arises in gas which follows the same dark-matter structures that the galaxies inhabit.Comment: 8 pages, invited review to appear in the proceedings of the Yale Cosmology Workshop on `The Shapes of Galaxies & their Halos", P. Natarajan, ed. Best figures found in (17Mb) PS file at http://astro.princeton.edu/~dvb/yale.p

Consumer satisfaction and dis-satisfaction with long-haul inclusive tours

This research is a qualitative study of consumer behaviour in tourism and specifically consumer satisfaction and dis-satisfaction (CS/D) with long-haul inclusive tours. An emphasisis placed on the supposed antecedents of CS/D - expectation, performance, disconfirmation, attribution, emotion, equity - and the change in CS/D through time. The research rationale was orientated to both the academic world and the world of practical management. A literature review and a series of interviews with senior management and directors of long-haul tour operators in Britain was followed by a participant observation case study on a long-haul tour of Malaysia and Singapore. A three-way perspective was sought on CS/D - from management, consumer service personnel and consumers. An interpretative framework, which synthesises the description and analysis in the literature search, primary interviews and participant observation, outlines the process of CS/D formation. This includes the interaction of a vortex of antececedents - with performance at the core - which then passes through a filter relating to both the specific and general context surrounding the long-haul tour. Either immediate or delayed CS/D judgements for micro events is followed by subsequent action or inaction by an individual consumer and/or other consumers in a group, a tour leader, a ground handler and/or a tour operator. A feedback loop completes a micro event cycle and engenders a cumulative development of consumer certainty with regard to the judgement of CS/D through time. Additionally, the study demonstrates the application and potential of participant observation - in lieu or in conjunction with other more familiar techniques - within both an academic and practical management perspective