Adapting robot behavior to user's capabilities: a dance instruction study.

The ALIZ-E1 projects goal is to design a robot companion able to maintain affective interactions with young users over a period of time. One of these interactions consists in teaching a dance to hospitalized children according to their capabilities. We propose a methodology for adapting both, the movements used in the dance based on the users cognitive and physical capabilities through a set of metrics, and the robots interaction based on the users personality traits

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Oxygen is a key element for life on earth. Oxygen concentrations in the ocean vary greatly in space and time. These changes are regulated by various physical and biogeochemical processes, such as primary productivity, sea surface temperatures and ocean circulation. In the geological past, several periods of widespread anoxia have been identified. These are typically accompanied with major perturbations of the cycles of carbon, phosphorus (P) and nitrogen (N). These are registered in the geological records and can be used to study Earth’s past environmental conditions. Our knowledge of the biogeochemical response to long-term deoxygenation in the ocean is still limited. This study focuses on the biogeochemistry in the ocean during a well-demarcated anoxic event that occurred in the mid-Cretaceous (94 Ma ago), when atmospheric CO2 levels were higher than at present. This event lasted approximately 550 kys and is termed Oceanic Anoxic Event 2 (OAE2). Most available geological records for OAE2 are from the North Atlantic, which during the mid-Cretaceous was a semi-enclosed deep basin (i.e. proto-North Atlantic) with a restricted connection to the Pacific and Tethys Ocean. In this research, a multi-box ocean model describing the cycles of water, carbon, oxygen, N and P of the proto-North Atlantic is built to better understand the key mechanisms involved in the development of widespread anoxia during OAE2. Because our knowledge of spatial variability in bottom-water conditions in the northern open ocean of the proto-North Atlantic is limited, proxy data from several deep-sea sites in the northern proto-North Atlantic were collected. Proxy data strongly suggest that, during OAE2, bottom waters in the entire deep proto-North Atlantic were anoxic and that the ocean circulation in the basin was restricted. Moreover, the N isotopic composition (δ15N) of organic matter buried in sediments in samples treated with acid led to selective removal of N compounds and thus should not be used to describe N dynamics in past environments. A compilation of published and new δ15N from samples that have not been treated with acid demonstrates that δ15N values for OAE2 are most negative in the open ocean (although values for OAE2 are never lower than -3 ‰). Our model results are in good agreement with observations, showing severe anoxia/euxinia in the open ocean and coastal waters of the southern proto-North Atlantic and strong oxygen depletion along the north and north-west coast. Our results indicate that high primary productivity and N2-fixation led to widespread anoxia in the proto-North Atlantic during OAE2. All P sources are a requirement for sustaining such primary productivity. Model results suggest that low-oxygen concentrations in the Pacific Ocean and reduced ocean circulation are needed for the development of anoxia in the deep northern proto-North Atlantic. In addition, ammonium accumulated due to limited nitrification and became the dominant recycled N nutrient. Model results also show significant regional differences in N dynamics, with the open ocean acting as a major source and sink of N, whereas the coastal ocean mainly acted as a source of N for non-diazotrophic primary productivity

Topological conditions for discrete symmetry breaking and phase transitions

In the framework of a recently proposed topological approach to phase transitions, some sufficient conditions ensuring the presence of the spontaneous breaking of a Z_2 symmetry and of a symmetry-breaking phase transition are introduced and discussed. A very simple model, which we refer to as the hypercubic model, is introduced and solved. The main purpose of this model is that of illustrating the content of the sufficient conditions, but it is interesting also in itself due to its simplicity. Then some mean-field models already known in the literature are discussed in the light of the sufficient conditions introduced here

Adaptive human-robot interaction in sensorimotor task instruction: From human to robot dance tutors

Den generella tilliten har i Sverige länge varit stabil och anses ur ett internationellt perspektiv vara unik. Syftet med denna studie är att studera om det finns ett samband mellan generell tillit och xenofobi. På grund av den minskade toleransen till främlingar under de senaste åren, studeras även hur generell den svenska tilliten egentligen är, eller om den generella tilliten är beroende av gruppspecifik tillit. Studien grundar sig på Robert Putnams teori om socialt kapital samt tidigare forskning som visat på sambandet mellan generell tillit och xenofobi. Studien använder sig av data från World Value Survey och behandlar svensk data från 2011. Studiens frågeställningar har besvarats genom en logistisk regressionsanalys. Resultaten visade ett positivt samband mellan låg in-gruppstillit och xenofobi samt ett positivt samband mellan låg ut-gruppstillit och xenofobi. Slutsatsen blev att det fanns ett samband mellan generell tillit och xenofobi. Detta samband kunde även till viss del förklaras av gruppspecifik tillit, där särskilt tillit till individer från andra kulturella sfärer än den egna var av betydelse

The frozen state in the liquid phase of side-chain liquid-crystal polymers

International audienceQuenched isotropic melts of side-chain liquid-crystal polymers reveal surprisingly an anisotropic polymer conformation. This small-angle neutron-scattering (SANS) result is consistent with the identification of a macroscopic, solidlike response in the isotropic phase. Both experiments (rheology and SANS) indicate that the polymer system appears frozen on millimeter length scales and at the time scales of the observation. This result implies that the flow behavior is not the terminal behavior and that cross-links or entanglements are not a necessary condition to provide elasticity in melts

Mendil et al Reply

International audienceIn the preceding Comment [1], Collin and Martinoty claim that a conventional flow behavior (G' ~ f2 , G'' ~ f) is obtained at 20 $\mu$m gap thickness, for a LC-polymer (LCP105) in the nematic phase, using a filling with a capillary, whereas a solidlike behavior (G' ~ Cst, G" ~ Cst) is observed by approaching two parallel surfaces to the sample (as we apply in our experiment). Our observations of a terminal solidlike behavior are thus interpreted by Collin and Martinoty as an anomaly induced by compression effects. We clearly refute this interpretation. We note that, on Fig. 13 and 14 of a previous paper written by Collin and Martinoty [2], they report no more a conventional flow but an elastic behavior at lower temperature using the capillary filling and the same polymer (LCP105). Their previous observations are thus in contradiction with their present purpose; i.e., a terminal flow behavior

Quadratic response theory for spin-orbit coupling in semiconductor heterostructures

This paper examines the properties of the self-energy operator in lattice-matched semiconductor heterostructures, focusing on nonanalytic behavior at small values of the crystal momentum, which gives rise to long-range Coulomb potentials. A nonlinear response theory is developed for nonlocal spin-dependent perturbing potentials. The ionic pseudopotential of the heterostructure is treated as a perturbation of a bulk reference crystal, and the self-energy is derived to second order in the perturbation. If spin-orbit coupling is neglected outside the atomic cores, the problem can be analyzed as if the perturbation were a local spin scalar, since the nonlocal spin-dependent part of the pseudopotential merely renormalizes the results obtained from a local perturbation. The spin-dependent terms in the self-energy therefore fall into two classes: short-range potentials that are analytic in momentum space, and long-range nonanalytic terms that arise from the screened Coulomb potential multiplied by a spin-dependent vertex function. For an insulator at zero temperature, it is shown that the electronic charge induced by a given perturbation is exactly linearly proportional to the charge of the perturbing potential. These results are used in a subsequent paper to develop a first-principles effective-mass theory with generalized Rashba spin-orbit coupling.Comment: 20 pages, no figures, RevTeX4; v2: final published versio

Electron-phonon interaction in the solid form of the smallest fullerene C20_{20}

The electron-phonon coupling of a theoretically devised carbon phase made by assembling the smallest fullerenes C$_{20}$ is calculated from first principles. The structure consists of C$_{20}$ cages in an {\it fcc} lattice interlinked by two bridging carbon atoms in the interstitial tetrahedral sites ({\it fcc}-C$_{22}$). The crystal is insulating but can be made metallic by doping with interstitial alkali atoms. In the compound NaC$_{22}$ the calculated coupling constant $\lambda/N(0)$ is 0.28 eV, a value much larger than in C$_{60}$, as expected from the larger curvature of C$_{20}$. On the basis of the McMillan's formula, the calculated $\lambda$=1.12 and a $\mu^*$ assumed in the range 0.3-0.1 a superconducting T$_c$ in the range 15-55 K is predicted.Comment: 7 page

A new and efficient approach to time-dependent density-functional perturbation theory for optical spectroscopy

Using a super-operator formulation of linearized time-dependent density-functional theory, the dynamical polarizability of a system of interacting electrons is given a matrix continued-fraction representation whose coefficients can be obtained from the non-symmetric block-Lanczos method. The resulting algorithm allows for the calculation of the {\em full spectrum} of a system with a computational workload which is only a few times larger than that needed for {\em static} polarizabilities within time-independent density-functional perturbation theory. The method is demonstrated with the calculation of the spectrum of benzene, and prospects for its application to the large-scale calculation of optical spectra are discussed.Comment: 4 pages, 2 figure

Assessment of laser-assisted micromanipulation procedures in a commercial bovine in vitro production laboratory

In vitro production (IVP) of bovine embryos is increasing yearly and is rapidly becoming the most commonly-used tool in cattle breeding. The drive for more efficient food production requires accelerated dissemination of superior cattle genetics. The implementation of advanced techniques such embryo biopsy and laser assisted hatching (LAH) with IVP embryos facilitates early genetic selection and could enhance pregnancy rates following embryo transfer. The nature and extent of chromosomal errors can also be established from embryo biopsies, and this could also improve pregnancy outcomes following embryo transfer. However, the techniques of bovine embryo biopsy and LAH are laborious, time consuming, utilise expensive equipment and require a high degree of technical skill. This thesis describes a series of experiments which sought to develop easy and robust methods for embryo biopsy and LAH in a commercial laboratory setting. It assessed the survivability and ‘hatchability’ of embryos compared to those that were not manipulated