Holographic thermalization in N=4 Super Yang-Mills theory at finite coupling

We investigate the behavior of energy momentum tensor correlators in holographic $\mathcal{N}=4$ super Yang-Mills plasma, taking finite coupling corrections into account. In the thermal limit we determine the flow of quasinormal modes as a function of the 't Hooft coupling. Then we use a specific model of holographic thermalization to study the deviation of the spectral densities from their thermal limit in an out-of-equilibrium situation. The main focus lies on the thermalization pattern with which the plasma constituents approach their thermal distribution as the coupling constant decreases from the infinite coupling limit. All obtained results point towards the weakening of the usual top-down thermalization pattern.Comment: 18 pages, 7 figures, v3: major revisio

Hyperfine Splitting and the Zeeman Effect in Holographic Heavy-Light Mesons

We inspect the mass spectrum of heavy-light mesons in deformed N=2 super Yang-Mills theory using the AdS/CFT correspondence. We demonstrate how some of the degeneracies of the supersymmetric meson spectrum can be removed upon breaking the supersymmetry, thus leading to the emergence of hyperfine structure. The explicit SUSY breaking scenarios we consider involve on one hand tilting one of the two fundamental D7 branes inside the internal R^6 space, and on the other hand applying an external magnetic field on the (untilted) branes. The latter scenario leads to the well-known Zeeman effect, which we inspect for both weak and strong magnetic fields.Comment: 5 pages, 1 figur

Intrinsic Dynamic Shape Prior for Fast, Sequential and Dense Non-Rigid Structure from Motion with Detection of Temporally-Disjoint Rigidity

While dense non-rigid structure from motion (NRSfM) has been extensively studied from the perspective of the reconstructability problem over the recent years, almost no attempts have been undertaken to bring it into the practical realm. The reasons for the slow dissemination are the severe ill-posedness, high sensitivity to motion and deformation cues and the difficulty to obtain reliable point tracks in the vast majority of practical scenarios. To fill this gap, we propose a hybrid approach that extracts prior shape knowledge from an input sequence with NRSfM and uses it as a dynamic shape prior for sequential surface recovery in scenarios with recurrence. Our Dynamic Shape Prior Reconstruction (DSPR) method can be combined with existing dense NRSfM techniques while its energy functional is optimised with stochastic gradient descent at real-time rates for new incoming point tracks. The proposed versatile framework with a new core NRSfM approach outperforms several other methods in the ability to handle inaccurate and noisy point tracks, provided we have access to a representative (in terms of the deformation variety) image sequence. Comprehensive experiments highlight convergence properties and the accuracy of DSPR under different disturbing effects. We also perform a joint study of tracking and reconstruction and show applications to shape compression and heart reconstruction under occlusions. We achieve state-of-the-art metrics (accuracy and compression ratios) in different scenarios

Marketing Wine on the Web

E-commerce is penetrating agriculture, particularly for selling products directly to consumers. The wine industry is a case in point. The industry has long-term experience in direct marketing. Many wineries welcome patrons at their premises for wine tasting and for selling wine to them. Moreover, where the practice is allowed, shipping wine directly to consumers without the assistance of trade intermediaries is a significant sales channel. E-commerce was adopted early in the wine industries of wired high-income countries and the wine industry provides an opportunity for studying the adoption, use, and impact of e-commerce. Moreover, because e-commerce has not spread evenly through all branches of agriculture, lessons learned from the wine industry may provide useful insights for entrepreneurs and policy makers concerned with sections of agriculture or the food industry where e-commerce adoption lags behind. The specific objectives of the dissertation research project which we report here therefore were: (1) to assess the extent of e-commerce diffusion in the wine industries of Australia, California, Germany; (2) to identify e-commerce practices used by wineries for marketing wine; (3) to explain differences in wineries' e-commerce practices, and (4) to derive insights and implications for sections of agriculture that lag behind in ecommerce adoption.Marketing,

Suboptimal Nutrient Intake in HIV-Infected Youth and Associations with Serum Lipid Profiles and HIV-Related Factors

Background: Few studies have evaluated habitual nutrient intake among HIV-infected youth in the United States, even though diet may influence disease progression and chronic complication risk. Objective: This study determined micro- and macronutrient intake in HIV-infected youth, and investigated relationships among nutrient intake, demographics, lipid profiles, and HIV-related factors. Design: HIV-infected subjects and healthy controls 1-25 years old were prospectively enrolled. Concomitant demographic, clinical and laboratory data were collected. Nutrient intake was assessed via 24-hr dietary recalls performed every 3 months for one year, analyzed with NDS-R software, and compared to Dietary Reference Intakes (DRIs) and Acceptable Macronutrient Distribution Ranges (AMDRs). Results: Subjects with ≥2 food recalls were analyzed (175 HIV+; 43 controls). Groups were similar in age, race, sex, body mass index, and kilocalorie intake. Both groups did not meet DRI for several micronutrients. HIV+ subjects had lower %DRI than controls for vitamins A, E, pantothenic acid, magnesium, calcium, folate and potassium. Percent kilocalories from fat was above normal and higher in HIV+ patients. Caloric intake was negatively correlated with current and nadir CD4 counts. Zinc, riboflavin, and magnesium %DRI were positively associated with current CD4+ count. In HIV+ subjects not on antiretroviral therapy, HIV-1 RNA levels were negatively correlated with protein intake. Conclusions: HIV+ youth have inadequate intake of several essential nutrients and poorer dietary intake compared to controls. Intake of some nutrients was associated with HIV-related factors. Further investigation is warranted to determine the impact of nutrition on HIV progression and chronic complication risk in this population

Thermalization at intermediate coupling

We use the AdS/CFT conjecture to investigate the thermalization of large-N_c N=4 Super Yang-Mills plasma in the limit of large but finite 't Hooft coupling. On the gravity side, we supplement the type IIB supergravity action by the full set of O(\alpha'^3) operators, which enables us to derive O(\lambda^{-3/2}) corrections to the emission spectrum of prompt photons in one model of holographic thermalization. Decreasing the coupling strength from the \lambda=\infty limit, we observe a qualitative change in the way the photon spectral density approaches its thermal limit as a function of the photon energy. We interpret this behavior as a sign of the thermalization pattern of the plasma shifting from top/down towards bottom/up.Comment: 5 pages, 3 figures; v2: minor corrections, added reference

Exploring nonlocal observables in shock wave collisions

We study the time evolution of 2-point functions and entanglement entropy in strongly anisotropic, inhomogeneous and time-dependent N=4 super Yang-Mills theory in the large N and large 't Hooft coupling limit using AdS/CFT. On the gravity side this amounts to calculating the length of geodesics and area of extremal surfaces in the dynamical background of two colliding gravitational shockwaves, which we do numerically. We discriminate between three classes of initial conditions corresponding to wide, intermediate and narrow shocks, and show that they exhibit different phenomenology with respect to the nonlocal observables that we determine. Our results permit to use (holographic) entanglement entropy as an order parameter to distinguish between the two phases of the cross-over from the transparency to the full-stopping scenario in dynamical Yang-Mills plasma formation, which is frequently used as a toy model for heavy ion collisions. The time evolution of entanglement entropy allows to discern four regimes: highly efficient initial growth of entanglement, linear growth, (post) collisional drama and late time (polynomial) fall off. Surprisingly, we found that 2-point functions can be sensitive to the geometry inside the black hole apparent horizon, while we did not find such cases for the entanglement entropy.Comment: 28 pp, 9 figs; v2: updated references, changed color bars in Figure 2 and Figure