Social presence, embarrassment, and nonverbal behavior

Nonverbal behaviors in response to viewing slides depicting nude males, nude females, erotic couples and neutral pictures, either alone or in the presence of two unfamiliar individuals, were studied in 22 female and 16 male university students. Participants were unaware of being videorecorded. Results revealed discrepancies between self-reported embarrassment and nonverbal behaviors supposedly expressive of embarrassment. Although self-reported embarrassment was higher when certain types of slides were viewed in the presence of others than when they were viewed alone, we observed significantly fewer lip movements, gaze shifts, face touches, downward gazes, and downward head movements in the presence of unfamiliar individuals than in the alone condition. We also compared behaviors during slide exposure and during the inter-slide intervals. For 9 out of 11 coded behaviors, frequencies were significantly higher during inter-slide intervals than during slide presentation. We argue that this is probably due to the fact that visual attention to the slides inhibited nonverbal behaviors. The results cast doubt on the possibility of inferring the internal state of an emotion such as embarrassment by analyzing nonverbal behaviors without taking account of the social setting in which such observations are made

Charge and mass effects on the evaporation of higher-dimensional rotating black holes

To study the dynamics of discharge of a brane black hole in TeV gravity scenarios, we obtain the approximate electromagnetic field due to the charged black hole, by solving Maxwell's equations perturbatively on the brane. In addition, arguments are given for brane metric corrections due to backreaction. We couple brane scalar and brane fermion fields with non-zero mass and charge to the background, and study the Hawking radiation process using well known low energy approximations as well as a WKB approximation in the high energy limit. We argue that contrary to common claims, the initial evaporation is not dominated by fast Schwinger discharge.Comment: Published version. Minor typos corrected. 29 pages, 5 figure

Are braneworlds born isotropic?

It has recently been suggested that an isotropic singularity may be a generic feature of brane cosmologies, even in the inhomogeneous case. Using the covariant and gauge-invariant approach we present a detailed analysis of linear perturbations of the isotropic model ${\cal F}_b$ which is a past attractor in the phase space of homogeneous Bianchi models on the brane. We find that for matter with an equation of state parameter $\gamma > 1$, the dimensionless variables representing generic anisotropic and inhomogeneous perturbations decay as $t\to 0$, showing that the model ${\cal F}_b$ is asymptotically stable in the past. We conclude that brane universes are born with isotropy naturally built-in, contrary to standard cosmology. The observed large-scale homogeneity and isotropy of the universe can therefore be explained as a consequence of the initial conditions if the brane-world paradigm represents a description of the very early universe.Comment: Changed to match published versio

A numerical study of confinement in compact QED

Compact U(1) lattice gauge theory in four dimensions is studied by means of an efficient algorithm which exploits the duality transformation properties of the model. We focus our attention onto the confining regime, considering the interquark potential and force, and the electric field induced by two infinitely heavy sources. We consider both the zero and finite temperature setting, and compare the theoretical predictions derived from the effective string model and the dual superconductor scenario to the numerical results.Comment: 31 pages, 16 eps figures; v2: references added; v3: footnote added, summation ranges in section 4 made explicit, version published in JHE

Experimental Study of rho -> pi0 pi0 gamma and omega -> pi0 pi0 gamma Decays

The e+e- -> pi0 pi0 gamma process was studied in the SND experiment at VEPP-2M e+e- collider in the energy region 0.60-0.97 GeV. From the analysis of the energy dependence of measured cross section the branching ratios B(omega -> pi0 pi0 gamma)= (6.6 +1.4-0.8(stat) +-0.6(syst))x10^-5 and B(rho -> pi0 pi0 gamma)=(4.1 +1.0-0.9(stat) +-0.3(syst))x10^-5 were obtained.Comment: 16 pages, 7 figures, submitted to Phys. Lett.

Disponibilidade do potássio do sienito nefelínico de Poços de Caldas, avaliada em cultivos sucessivos com milho

The availability of K of the potassium rock (nepheline sienite) from Poços de Caldas was studied under greenhouse conditions through successive croppings using corn plants grown in Dark Red Latossol (DRL) and "Terra Roxa Estruturada" (TRE) in presence and absence of liming. Addition of KCl showed significant effects on dry matter yields, regardless of liming. This response was linear and higher in LVE than in TRE. KCl doses greater than 200 ppm of K reduced dry matter production in TRE. After the first cropping, dry matter yields were drastically reduced and this seems to be due to the depletion of available K in the soil. The potassium rock had little effect on corn growth, but when it was applied at rate of 300 ppm of K, significant positive response in dry matter accumulation was found for DRL with liming. The reduced effect of this rock is due to its low K-supplying capacity even by the third cropping, as shown by the total K absorption by the plant. These data support earlier studies using chemical extractors in the laboratory and show the low availability of the K from this rock to corn plants. It is suggested that potassium rock "in natura" can not be used as potassium source for corn.A disponibilidade do potássio da rocha potássica de Poços de Caldas (sienito nefelínico) foi estudada em condições de casa de vegetação através de cultivos sucessivos com milho cultivado em Latossolo Vermelho-Escuro (LVE) e Terra Roxa Estruturada (TRE), com presença ou ausência de calagem. A aplicação de KCl mostrou respostas significativas na produção de matéria seca, independentemente da calagem. Estas respostas foram lineares e mais acentuadas no LVE do que na TRE, na qual, doses de KCl maiores que 200 ppm reduziram a produção de matéria seca. Após o primeiro cultivo, a produção de matéria seca foi muito pequena, e isto parece ser devido ao esgotamento do K disponível no solo. A rocha potássica exerceu pouco efeito na produção de matéria seca, mostrando efeito positivo apenas no LVE na dose de 300 ppm de K na presença de calagem. O reduzido efeito da rocha foi devido à sua baixa capacidade de fornecer potássio, mesmo no terceiro cultivo, conforme mostram os dados de absorção de potássio pela planta. Os dados obtidos confirmam os estudos já realizados com a utilização de extratores químicos em laboratório, e mostram a baixa disponibilidade do potássio desta rocha para o milho. A rocha potássica "in natura", não se presta como fertilizante potássico para o milho

Giant gravitons in AdS/CFT (I): matrix model and back reaction

In this article we study giant gravitons in the framework of AdS/CFT correspondence. First, we show how to describe these configurations in the CFT side using a matrix model. In this picture, giant gravitons are realized as single excitations high above a Fermi sea, or as deep holes into it. Then, we give a prescription to define quasi-classical states and we recover the known classical solution associated to the CFT dual of a giant graviton that grows in AdS. Second, we use the AdS/CFT dictionary to obtain the supergravity boundary stress tensor of a general state and to holographically reconstruct the bulk metric, obtaining the back reaction of space-time. We find that the space-time response to all the supersymmetric giant graviton states is of the same form, producing the singular BPS limit of the three charge Reissner-Nordstr\"om-AdS black holes. While computing the boundary stress tensor, we comment on the finite counterterm recently introduced by Liu and Sabra, and connect it to a scheme-dependent conformal anomaly.Comment: 28 pages, JHEP3 class. v2: typos corrected and references adde

Evidence of two-electron tunneling interference in Nb/InAs junctions

The impact of junction transparency in driving phase-coherent charge transfer across diffusive semiconductor-superconductor junctions is demonstrated. We present conductivity data for a set of Nb-InAs junctions differing only in interface transparency. Our experimental findings are analyzed within the quasi-classical Green-function approach and unambiguously show the physical processes giving rise to the observed excess zero-bias conductivity.Comment: 10 pages (RevTex), 4 figures (PostScript), accepted for pubblication in Physical Review