The attitudes, feelings and experiences of online gamers: a qualitative analysis

The playing of massively multiplayer online role-playing games (MMORPGs) is now a highly popular leisure activity. The present study set out to explore the attitudes, experiences, and feelings of online gamers. The study entailed 71 interviews with online gamers (52 males, 19 females) from 11 different countries. Six main themes emerged from the analyses of the interview transcripts: (a) online gaming and integration into day-to-day lives; (b) online gaming, excessive play, and problems; (c) addiction; (d) psychosocial impact of online gaming; (e) online gaming, dissociation, and time loss; and (f) online gaming and the alleviation of negative feelings and mood states. These findings specifically showed how gamers used MMORPGs to alleviate negative feelings and provided detailed descriptions of personal problems that had arisen due to playing MMORPGs. The implications of these findings are discussed in relation to previous qualitative and quantitative research in the area

Black hole - D-brane correspondence: An example

We explore the connection between D-branes and black holes in one particular case: a $D3$-brane compactified to four dimensions on $T^6/Z_3$. Using the $D$-brane boundary state description we show the equivalence with a double extremal N=2 black hole solution of four dimensional supergravity.Comment: 15 pages, LaTeX. Contribution by C. Nunez to the conference Quantum Gravity in the Southern Cone, Bariloche 7-10 January 1998; to appear in the proceeding

Chaos in a spatially-developing plane mixing layer

A spatially-developing plane mixing layer was analyzed for chaotic behavior. A direct numerical simulation of the Navier-Stokes equations in a 2-D domain infinite in y and having inflow-outflow boundary conditions in x was used for data. Spectra, correlation dimension and the largest Lyapunov exponent were computed as functions of downstream distance x. When forced at a single (fundamental) frequency with maximum amplitude, the flow is periodic at the inflow but becomes aperiodic with increasing x. The aperiodic behavior is caused by the presence of a noisy subharmonic caused by the feedback between the necessarily nonphysical inflow and outflow boundary conditions. In order to overshadow this noise the flow was also studied with the same fundamental forcing and added random forcing of amplitude upsilon prime sub R/delta U = 0.01 at the inlet. Results were qualitatively the same in both cases: for small x, spectral peaks were sharp and dimension was nearly 1, but as x increased a narrowband spectral peak grew, spectra decayed exponentially at high frequencies and dimension increased to greater than 3. Based on these results, the flow appears to exhibit deterministic chaos. However, at no location was the largest Lyapunov exponent found to be significantly greater than zero

The electrical conductivity of cellulosic derivatives in the presence of moisture

The work presented in this thesis consists of a review of previous work on cellulosic materials and related polymers, and the results of an experimental investigation into the electrical conductivity of cellulosic derivatives (cellulose acetate, cellulose acetate butyrate) in the presence of moisture. The experimental work for the present investigation has been carried out in three parts. The first part concerns the preparation of thin films of cellulose acetate and cellulose acetate butyrate from the raw material using a casting technique. The second and major part of the experimental work concerns electrical measurements, including the measurement of dielectric constant dielectric loss and volume conductance under different conditions of humidity and contamination, etc. These follow the experiments made by Barker and Thomas on the effect of moisture and high electric fields on conductivity in alkali-halide doped cellulose acetate. The third and the final part of the experimental work deals with the sorption measurements, i.e. the sorption isotherms for the materials and their correlation with the electrical measurements. This part is incomplete. The results obtained are in agreement with the results of Barker and Thomas and the two materials have given similar results. However the work has been extended beyond the original work of Barker and Thomas and significant disagreement has been found with their work. In particular results obtained at different humidity do not support the theory proposed by Barker and Thomas. The surface conductance of the specimens was measured and was found to be negligible at all humidities. It is concluded that there is no surface conduction on these materials

Entangling the optical frequency comb: simultaneous generation of multiple 2x2 and 2x3 continuous-variable cluster states in a single optical parametric oscillator

We report on our research effort to generate large-scale multipartite optical-mode entanglement using as few physical resources as possible. We have previously shown that cluster- and GHZ-type N-partite continuous-variable entanglement can be obtained in an optical resonator that contains a suitably designed second-order nonlinear optical medium, pumped by at most O(N^2) fields. In this paper, we show that the frequency comb of such a resonator can be entangled into an arbitrary number of independent 2x2 and 2x3 continuous-variable cluster states by a single optical parametric oscillator pumped by just a few optical modes.Comment: Third version has corrected eqs. (10-14) and revised notation "Q" in lieu of "X" for amplitude quadrature operato

Use of Dynamic Assessment With Children in the Early Years Foundation Stage: A Review of the Literature

In England, the Early Years Foundation Stage (EYFS) curriculum (ages 0 to 5) emphasises the use of a play-based approach, focusing on the needs, interests and developmental stages of children. Dynamic assessment (DA) represents an opportunity for educational psychologists (EPs) (Hill, 2015) to utilise a play-based approach for assessing the functional behaviour of children who find it difficult to engage with formal and static testing situations (Tzuriel, 2000). However, it is one of the least utilised methods in EP practice (Hill, 2015). Using systematic literature review methodology and research quality assessment frameworks, this paper examines the usefulness of DA with children in the EYFS. The review indicated mixed results for the usefulness of DA. DA added value to static assessments for cognitive and linguistic functioning, reduced the risk of biased assessment and contributed predictive information about later independence. Future research should explore EPs’ use of DA in the EYFS

Ultracompact Generation of Continuous-Variable Cluster States

We propose an experimental scheme that has the potential for large-scale realization of continuous-variable (CV) cluster states for universal quantum computation. We do this by mapping CV cluster-state graphs onto two-mode squeezing graphs, which can be engineered into a single optical parametric oscillator (OPO). The desired CV cluster state is produced directly from a joint squeezing operation on the vacuum using a multi-frequency pump beam. This method has potential for ultracompact experimental implementation. As an illustration, we detail an experimental proposal for creating a four-mode square CV cluster state with a single OPO.Comment: 4 pages, 1 figure; v2 improved discussion of the implications of our result; added discussion of finite squeezing effect

Optical Non-Orthogonal Multiple Access for Visible Light Communication

The proliferation of mobile Internet and connected devices, offering a variety of services at different levels of performance, represents a major challenge for the fifth generation wireless networks and beyond. This requires a paradigm shift towards the development of key enabling techniques for the next generation wireless networks. In this respect, visible light communication (VLC) has recently emerged as a new communication paradigm that is capable of providing ubiquitous connectivity by complementing radio frequency communications. One of the main challenges of VLC systems, however, is the low modulation bandwidth of the light-emitting-diodes, which is in the megahertz range. This article presents a promising technology, referred to as "optical- non-orthogonal multiple access (O-NOMA)", which is envisioned to address the key challenges in the next generation of wireless networks. We provide a detailed overview and analysis of the state-of-the-art integration of O-NOMA in VLC networks. Furthermore, we provide insights on the potential opportunities and challenges as well as some open research problems that are envisioned to pave the way for the future design and implementation of O-NOMA in VLC systems

Mapping the spin-dependent electron reflectivity of Fe and Co ferromagnetic thin films

Spin Polarized Low Energy Electron Microscopy is used as a spin dependent spectroscopic probe to study the spin dependent specular reflection of a polarized electron beam from two different magnetic thin film systems: Fe/W(110) and Co/W(110). The reflectivity and spin-dependent exchange-scattering asymmetry are studied as a function of electron kinetic energy and film thickness, as well as the time dependence. The largest value of the figure of merit for spin polarimetry is observed for a 5 monolayer thick film of Co/W(110) at an electron kinetic energy of 2eV. This value is 2 orders of magnitude higher than previously obtained with state of the art Mini-Mott polarimeter. We discuss implications of our results for the development of an electron-spin-polarimeter using the exchange-interaction at low energy.Comment: 5 pages, 4 figure