Semileptonic form factor ratio B_s->D_s/B->D and its application to BR(B^0_s->\mu^+\mu^-)

We present a (2+1)-flavor lattice QCD calculation of the form factor ratio between the semileptonic decays $\bar{B}^0_s \to D^+_sl^-\bar{\nu}$ and $\bar{B}^0 \to D^+l^-\bar{\nu}$. This ratio is an important theoretical input to the hadronic determination of the $B$ meson fragmentation fraction ratio $f_s/f_d$ which enters in the measurement of $\mathrm{BR}(B^0_s\to \mu^+\mu^-)$. Small lattice spacings and high statistics enable us to simulate the decays with a dynamic final $D$ meson of small momentum and reliably extract the hadronic matrix elements at nonzero recoil. We report our preliminary result for the form factor ratio at the corresponding momentum transfer of the two decays $f_0^{(s)}(M^2_\pi)/f_0^{(d)}(M^2_K)$.Comment: 7 pages, 6 figures. Talk presented at The XXIX International Symposium on Lattice Field Theory - Lattice 2011, July 10-16, 2011, Squaw Valley, Lake Tahoe, California; Minor errors corrected, references and graphs update

Semileptonic B to D decays at nonzero recoil with 2+1 flavors of improved staggered quarks. An update

The Fermilab Lattice and MILC collaborations are completing a comprehensive program of heavy-light physics on MILC (2+1)-flavor asqtad ensembles with lattice spacings as small as 0.045 fm and light-to-strange-quark mass ratios as low as 1/20. We use the Fermilab interpretation of the clover action for heavy valence quarks and the asqtad action for the light valence quarks. The central goal of the program is to provide ever more exacting tests of the unitarity of the CKM matrix. We present preliminary results for one part of the program, namely the analysis of the semileptonic decay B -> D l nu at nonzero recoil.Comment: 7 pp, 7 figs, Lattice 201

Minimal molecular building blocks for screening in quasi-two-dimensional organic–inorganic lead halide perovskites

Layered hybrid organic–inorganic lead halide perovskites have intriguing optoelectronic properties, but some of the most interesting perovskite systems, such as defective, disordered, or mixed perovskites, require multiple unit cells to describe and are not accessible within state-of-the-art ab initio theoretical approaches for computing excited states. The principal bottleneck is the calculation of the dielectric matrix, which scales formally as O(N4). We develop here a fully ab initio approximation for the dielectric matrix, known as IPSA-2C, in which we separate the polarizability of the organic/inorganic layers into minimal building blocks, thus circumventing the undesirable power-law scaling. The IPSA-2C method reproduces the quasi-particle band structures and absorption spectra for a series of Ruddlesden–Popper perovskites to high accuracy, by including critical nonlocal effects neglected in simpler models, and sheds light on the complicated interplay of screening between the organic and inorganic sublattices

Embodied Metaphors and Creative “Acts”

Creativity is a highly sought after skill. To inspire people’s creativity, prescriptive advice in the form of metaphors abound: We are encouraged to think outside the box, to consider the problem on one hand, then on the other hand, and to put two and two together to achieve creative breakthroughs. These metaphors suggest a connection between concrete bodily experiences and creative cognition. Inspired by recent advances on body-mind linkages under the emerging vernacular of embodied cognition, we explored for the first time whether enacting metaphors for creativity enhances creative problem-solving. In five studies, findings revealed that both physically and psychologically embodying creative metaphors promote fluency, flexibility, and/or originality in problem-solving. Going beyond prior research that focused primarily on the kind of embodiment that primes preexisting knowledge, we provide the first evidence that embodiment can also activate cognitive processes conducive for generating previously unknown ideas and connections

Recensão do Livro The Platform Economy: How Japan Transformed the Consumer Internet

Since around mid-2010s, “platform” companies such as Google, Amazon, and Uber have come under intense criticism. These tech giants from the Silicon Valley are problematic because their business model centers on secretive data surveillance and targeted marketing. They are socially irresponsible with tax evasions and liabilities for precarious labor. Their digital media imperialism is detrimental to the world for it undermines independent innovation at the national and local levels. The question is, can it be otherwise?  “Plataformas” digitais como Google, Amazon e Uber têm vindo a ser alvo de duras críticas desde meados da década de 2010. Estes gigantes tecnológicos de Silicon Valley são problemáticos, uma vez que os seus modelos de negócio se baseiam na vigilância secreta de dados e em marketing direcionado. A sua ausência de responsabilidade social traduz-se em evasão fiscal e trabalho precário. A sua natureza imperialista, enquanto media digital, é prejudicial porquanto mina a inovação independente, quer a nível nacional, quer a nível local. A questão que se coloca é, poderia ser de outra forma

THE PERSUASIVE IMPACT OF EMOTICONS IN ONLINE WORD-OF-MOUTH COMMUNICATION

The present research proposes a conceptual framework to examine the effect of emoticons on online WOM persuasion. Using a laboratory experiment, we demonstrate that emoticons enhance recipients’ empathy for the communicator, and this effect is moderated by message valence. Enhanced empathy heightens perceived trustworthiness of the communicator and perceived quality of the message, both of which lead to an increase in the persuasiveness of the WOM message. We conclude by discussing the contributions of this research and identifying the directions for future research

Obwody pracy: teoria pracy dla epoki iPhone’ów

This paper questions the binary of material and immaterial labour in the information era. Instead, we propose a “circuits of labour” model, a holistic framework that helps connect various concepts and traditions in the study of labour and ICT (information and communication technology). Inspired by du Gay et al’s “circuit of culture”, we argue conventional frameworks need to be synthesized and updated to reflect fundamental changes and persisting issues of labor in our contemporary era, of which the iPhone is emblematic. On the one hand, our model consists of formal circuits, in which hierarchical domination is imposed by capital over the body of labour. On the other hand, it consists of informal circuits where relationships are defined communally between embodied practices and social and communicative capital. The informal and formal circuits of labour are “short-circuited” by survival labour and ‘playbour’, meaning either circuit may absorb productive energy from the other. This article then uses the case of Foxconn, the world’s largest electronic manufacturer that also produces iPhones, to illustrate the usefulness of the “circuits of labour” model. We finally discuss the broader implications and questions for future research.Tekst kwestionuje binarny podział na pracę materialną i niematerialną w epoce informacji. W zamian proponujemy model „obwodów pracy” – holistyczną perspektywę, która ułatwia połączenie różnorodnych pojęć i tradycji w studiach nad pracą i ICT (technologie informacyjne i komunikacyjne). Posiłkując się teorią „obwodu kultury” Du Gaya i jego współpracowników, argumentujemy, że stosowane powszechnie perspektywy powinny zostać poddane syntezie i aktualizacji, by oddać fundamentalne przemiany, jakim współcześnie podlega praca, jak również wskazać na najpoważniejsze problemy z tym związane. Dla tych wszystkich procesów iPhone jest naszym zdaniem zjawiskiem emblematycznym. Z jednej strony w skład naszego modelu wchodzą formalne obwody, w ramach których hierarchiczna dominacja narzucana jest pracującemu ciału przez kapitał. Z drugiej strony zaś obejmuje on nieformalne obwody, w ramach których stosunki definiowane są zarówno przez ucieleśnione praktyki, jak i społeczny i komunikacyjny kapitał. Obwody formalny i nieformalny wchodzą ze sobą w spięcia w kontekście obwodów przetrwania i pracozabawy, co oznacza, że każdy z tych obwodów może wchłonąć produktywną energię wytworzoną przez każdy z nich. W niniejszym artykule przywołujemy przykład Foxconna, największego wytwórcy sprzętu elektronicznego na świecie, który produkuje także iPhone’a. Służy to zilustrowaniu użyteczności proponowanego przez nas modelu „obwodów pracy”. Podsumowując artykuł, poddajemy dyskusji szersze konsekwencje i kwestie istotne z perspektywy dalszych badań