Charm contribution to bulk viscosity

In the range of temperatures reached in future heavy ion collision experiments, hadronic pair annihilations and creations of charm quarks may take place within the lifetime of the plasma. As a result, charm quarks may increase the bulk viscosity affecting the early stages of hydrodynamic expansion. Assuming thermalisation, we estimate the charm contribution to bulk viscosity within the same effective kinetic theory framework in which the light parton contribution has been computed previously. The time scale at which this physics becomes relevant is related to the width of the transport peak associated with the trace anomaly correlator and is found to be ≲20 fm/c for T≳600 MeV.

Search for new particles in events with one lepton and missing transverse momentum in pp collisions at √s = 8 TeV with the ATLAS detector

This paper presents a search for new particles in events with one lepton (electron or muon) and missing transverse momentum using 20.3 fb−1 of proton-proton collision data at TeX = 8 TeV recorded by the ATLAS experiment at the Large Hadron Collider. No significant excess beyond Standard Model expectations is observed. A W ′ with Sequential Standard Model couplings is excluded at the 95% confidence level for masses up to 3.24 TeV. Excited chiral bosons (W *) with equivalent coupling strengths are excluded for masses up to 3.21 TeV. In the framework of an effective field theory limits are also set on the dark matter-nucleon scattering cross-section as well as the mass scale M * of the unknown mediating interaction for dark matter pair production in association with a leptonically decaying W.

Search for dark matter in events with a Z boson and missing transverse momentum in pp collisions at √s=8 TeV with the ATLAS detector

search is presented for production of dark-matter particles recoiling against a leptonically decaying Z boson in 20.3 fb−1 of pp collisions at √s=8 TeV with the ATLAS detector at the Large Hadron Collider. Events with large missing transverse momentum and two oppositely charged electrons or muons consistent with the decay of a Z boson are analyzed. No excess above the Standard Model prediction is observed. Limits are set on the mass scale of the contact interaction as a function of the dark-matter particle mass using an effective field theory description of the interaction of dark matter with quarks or with Z bosons. Limits are also set on the coupling and mediator mass of a model in which the interaction is mediated by a scalar particle.

Standard Model thermodynamics across the electroweak crossover

Even though the Standard Model with a Higgs mass mH = 125GeV possesses no bulk phase transition, its thermodynamics still experiences a "soft point" at temperatures around T = 160GeV, with a deviation from ideal gas thermodynamics. Such a deviation may have an effect on precision computations of weakly interacting dark matter relic abundances if their mass is in the few TeV range, or on leptogenesis scenarios operating in this temperature range. By making use of results from lattice simulations based on a dimensionally reduced effective field theory, we estimate the relevant thermodynamic functions across the crossover. The results are tabulated in a numerical form permitting for their insertion as a background equation of state into cosmological particle production/decoupling codes. We find that Higgs dynamics induces a non-trivial "structure" visible e.g. in the heat capacity, but that in general the largest radiative corrections originate from QCD effects, reducing the energy density by a couple of percent from the free value even at T > 160GeV.

Engineered surface waves in hyperbolic metamaterials

We analyzed surface-wave propagation that takes place at the boundary between a semi-infinite dielectric and a multilayered metamaterial, the latter with indefinite permittivity and cut normally to the layers. Known hyperbolization of the dispersion curve is discussed within distinct spectral regimes, including the role of the surrounding material. Hybridization of surface waves enable tighter confinement near the interface in comparison with pure-TM surface-plasmon polaritons. We demonstrate that the effective-medium approach deviates severely in practical implementations. By using the finite-element method, we predict the existence of long-range oblique surface waves.

Dyakonov surface waves in lossy metamaterials

We analyze the existence of localized waves in the vicinities of the interface between two dielectrics, provided one of them is uniaxial and lossy. We found two families of surface waves, one of them approaching the well-known Dyakonov surface waves (DSWs). In addition, a new family of wave fields exists which are tightly bound to the interface. Although its appearance is clearly associated with the dissipative character of the anisotropic material, the characteristic propagation length of such surface waves might surpass the working wavelength by nearly two orders of magnitude.

Universal Non-Debye Scaling in the Density of States of Amorphous Solids.

At the jamming transition, amorphous packings are known to display anomalous vibrational modes with a density of states (DOS) that remains constant at low frequency. The scaling of the DOS at higher packing fractions remains, however, unclear. One might expect to find a simple Debye scaling, but recent results from effective medium theory and the exact solution of mean-field models both predict an anomalous, non-Debye scaling. Being mean-field in nature, however, these solutions are only strictly valid in the limit of infinite spatial dimension, and it is unclear what value they have for finite-dimensional systems. Here, we study packings of soft spheres in dimensions 3 through 7 and find, away from jamming, a universal non-Debye scaling of the DOS that is consistent with the mean-field predictions. We also consider how the soft mode participation ratio evolves as dimension increases.

Performatividad y arte computacional. Hacia una “DIY society”

El artículo analiza la figura del prosumidor desde los estudios visuales a partir de la combinación de la teoría de los actos de habla y los nuevos medios. El objetivo es evaluar si la distinción entre productores y consumidores, estrategias y tácticas de Michel de Certeau continúa siendo operativa en las interfaces gráficas de la cultura global de la información de Scott Lash. Para ello distingue dos tipos de performatividad de los actos de habla: la performatividad top-down del software, y la bottom-up de los juegos del lenguaje y las formas de vida. Estos tipos se aplican al análisis del discurso de los eslóganes que aparecen en los sitios web de las iniciativas “open” y de economía colaborativa, ya que las primeras están dedicadas a la producción de bienes inmateriales y las segundas a la producción de bienes materiales. El desarrollo muestra cómo los dos tipos de performatividad transforman el análisis textual de los estudios literarios y cinematográficos en una metodología capaz de investigar acciones materiales, humanas y no humanas. Las conclusiones describen el surgimiento de nuevas convenciones narrativas de poder y control ajenas a la ficción que apuntan a una “DIY society”.

Laadun ja oikean tiedon varmistaminen pk-yrityksen tilaus-toimitusketjussa

Oikean tiedon siirtyminen oikeaan aikaan, sekä laadukkaan työn tekeminen yrityksen tilaus-toimitusketjun jokaisessa vaiheessa, ovat avaintekijöitä arvolupauksen ja laadun täyttämiseen asiakkaalle. Diplomityön tavoite on kehittää pk-yritykselle työkalut parempaan tiedon hallintaan ja laadukkaan työn tekemiseen toiminnanohjausjärjestelmässä. Tutkimusmenetelmänä diplomityössä käytettiin toimintatutkimusta, jossa diplomityön tekijä osallistui kohdeyrityksen päivittäiseen työn tekemiseen neljän kuukauden ajan. Tutkimuksen tiedon keräämisessä käytettiin myös puolistrukturoitua haastattelua, sekä kyselytutkimuksella. Tutkimusote työssä on kvalitatiivinen eli laadullinen tutkimusote. Työ koostuu teoriaosasta sekä soveltavasta osasta, jonka jälkeen työn tulokset esitetään tiivistetysti johtopäätöksissä ja yhteenvedossa. Toiminnanohjausjärjestelmät keräävät ja tallentavat tietoa, jota työntekijät ja yrityksen rajapinnoilla työskentelevät ihmiset siihen syöttävät. Onkin äärimmäisen tärkeää, että yrityksellä on kuvatut yhtenäiset toimintamallit prosesseille, joita he käyttävät tiedon tallentamisessa järjestelmiin. Tässä diplomityössä tutkitaan pk-yrityksen nykyiset toimintamallit tiedon tallentamisesta toiminnanohjausjärjestelmään, jonka jälkeen kehitetään yhtenäiset ohjeet toiminnanohjausjärjestelmään syötetystä myyntitilaussopimuksesta. Teoriaosuudessa esitetään laatu eri näkökulmista ja mitä laadunhallintajärjestelmät ovat ja kuinka niitä kehitetään. Teoriaosassa myös avataan tilausohjautuvan tuotannon periaatteet, sekä toiminnanohjausjärjestelmän merkitys liiketoiminnalle. Teoriaosuudella pohjustetaan soveltavaa osuutta, jossa ongelma-analyysin jälkeen kehitetään yritykseen oma laadunhallintajärjestelmä, sekä uudet työmallit tiedonvaihtoon ja sen tallentamiseen. Tuloksena on myös toiminnanohjausjärjestelmän käytön tehostuminen ohjelmistotoimittajan tekemänä. Ohjelmasta karsittiin turhat nimikkeistöt ja sen konfigurointia tehostettiin. Työn tuloksena saatiin työohjeet ydinprosessien suorittamiseen, sekä oma laadunhallintajärjestelmä tukemaan yrityksen ydin- ja tukiprosesseja, sekä tiedonhallintaa.

Optical properties of semiconductor quantum wires

This thesis presents theoretical investigations of the sub band structure and optical properties of semiconductor quantum wires. For the subband structure, we employ multiband effective-mass theory and the effective bond-orbital model both of which fully account for the band mixing and material anisotropy. We also treat the structure geometry in detail taking account of such effects as the compositional grading across material interfaces. Based on the subband structure, we calculate optical properties of quantum-wire structures. A recuring theme is the cross-over from one- to ~wo-dimensional behavior in these structures. This complicated behavior procludes the application of simple theoretical models to obtain the electronic structure. In particular, we calculate laser properties of quantum wires grown in V-grooves and find enhanced performance compared with quantum-well lasers. We also investigate optical anisotropy in quantum-wire arrays and propose an electro-optic device based on such structures.

Single-Polarization Double Refraction in Plasmonic Crystals: Considerations on Energy Flow

We examined the optical properties of nanolayered metal-dielectric lattices. At subwavelength regimes, the periodic array of metallic nanofilms demonstrates nonlocality-induced double refraction, conventional positive and as well as negative. In particular, we report on energy-flow considerations concerning both refractive behaviors concurrently. Numerical simulations provide transmittance of individual beams in Ag-TiO2 metamaterials under different configurations. In regimes of the effective-medium theory predicting elliptic dispersion, negative refraction may be stronger than the expected positive refraction.

Application of effective medium approximation theory to ocean remote sensing under wave breaking

Based on the effective medium approximation theory of composites, the empirical model proposed by Pandey and Kakar is remedied to investigate the microwave emissivity of sea surface under wave breaking driven by strong wind. In the improved model, the effects of seawater bubbles, droplets and difference in temperature of air and sea interface (DTAS) on the emissivity of sea surface covered by whitecaps are discussed. The model results indicate that the effective emissivity of sea surface increases with DTAS increasing, and the impacts of bubble structures and thickness of whitecaps layer on the emissivity are included in the model by introducing the effective dielectric constant of whitecaps layer. Moreover, a good agreement is obtained by comparing the model results with the Rose's experimental data.

Boys 'doing' and 'undoing' media education : new possibilities for theory and practice

The purpose of this study is to investigate how secondary school media educators might best meet the needs of students who prefer practical production work to ‘theory’ work in media studies classrooms. This is a significant problem for a curriculum area that claims to develop students’ media literacies by providing them with critical frameworks and a metalanguage for thinking about the media. It is a problem that seems to have become more urgent with the availability of new media technologies and forms like video games. The study is located in the field of media education, which tends to draw on structuralist understandings of the relationships between young people and media and suggests that students can be empowered to resist media’s persuasive discourses. Recent theoretical developments suggest too little emphasis has been placed on the participatory aspects of young people playing with, creating and gaining pleasure from media. This study contributes to this ‘participatory’ approach by bringing post structuralist perspectives to the field, which have been absent from studies of secondary school media education. I suggest theories of media learning must take account of the ongoing formation of students’ subjectivities as they negotiate social, cultural and educational norms. Michel Foucault’s theory of ‘technologies of the self’ and Judith Butler’s theories of performativity and recognition are used to develop an argument that media learning occurs in the context of students negotiating various ‘ethical systems’ as they establish their social viability through achieving recognition within communities of practice. The concept of ‘ethical systems’ has been developed for this study by drawing on Foucault’s theories of discourse and ‘truth regimes’ and Butler’s updating of Althusser’s theory of interpellation. This post structuralist approach makes it possible to investigate the ways in which students productively repeat and vary norms to creatively ‘do’ and ‘undo’ the various media learning activities with which they are required to engage. The study focuses on a group of year ten students in an all boys’ Catholic urban school in Australia who undertook learning about video games in a three-week intensive ‘immersion’ program. The analysis examines the ethical systems operating in the classroom, including formal systems of schooling, informal systems of popular cultural practice and systems of masculinity. It also examines the students’ use of semiotic resources to repeat and/or vary norms while reflecting on, discussing, designing and producing video games. The key findings of the study are that students are motivated to learn technology skills and production processes rather than ‘theory’ work. This motivation stems from the students’ desire to become recognisable in communities of technological and masculine practice. However, student agency is not only possible through critical responses to media, but through performative variation of norms through creative ethical practices as students participate with new media technologies. Therefore, the opportunities exist for media educators to create the conditions for variation of norms through production activities. The study offers several implications for media education theory and practice including: the productive possibilities of post structuralism for informing ways of doing media education; the importance of media teachers having the autonomy to creatively plan curriculum; the advantages of media and technology teachers collaborating to draw on a broad range of resources to develop curriculum; the benefits of placing more emphasis on students’ creative uses of media; and the advantages of blending formal classroom approaches to media education with less formal out of school experiences.

Australian media ethics regime and ethical risk management

Media organizations are simultaneously key elements of an effective democracy and, for the most part, commercial entities seeking success in the market. They play an essential role in the formation of public opinion and the influence on personal choices. Yet most of them are commercial enterprises seeking readers or viewers, advertising, favorable regulatory decisions for their media, and other assets. This creates some intrinsic difficulties and produces some sharp tensions within media ethics. In this article, we examine such tensions—in theory and practice. We then consider the feasibility of introducing an ethics regime to the media industry—a regime that would be effective in a deregulated environment in protecting public interest and social responsibility. In the article, we also outline a rationale and a methodology for the institutionalization of an acceptable and workable media ethics regime that aims to protect the integrity of the industry in a future of undoubtedly increasing commercial pressure.