50 research outputs found
Deep affect prediction in-the-wild: Aff-wild database and challenge, deep architectures, and beyond
Automatic understanding of human affect using visual signals is of great importance in everyday human–machine interac- tions. Appraising human emotional states, behaviors and reactions displayed in real-world settings, can be accomplished using latent continuous dimensions (e.g., the circumplex model of affect). Valence (i.e., how positive or negative is an emo- tion) and arousal (i.e., power of the activation of the emotion) constitute popular and effective representations for affect. Nevertheless, the majority of collected datasets this far, although containing naturalistic emotional states, have been captured in highly controlled recording conditions. In this paper, we introduce the Aff-Wild benchmark for training and evaluating affect recognition algorithms. We also report on the results of the First Affect-in-the-wild Challenge (Aff-Wild Challenge) that was recently organized in conjunction with CVPR 2017 on the Aff-Wild database, and was the first ever challenge on the estimation of valence and arousal in-the-wild. Furthermore, we design and extensively train an end-to-end deep neural architecture which performs prediction of continuous emotion dimensions based on visual cues. The proposed deep learning architecture, AffWildNet, includes convolutional and recurrent neural network layers, exploiting the invariant properties of convolutional features, while also modeling temporal dynamics that arise in human behavior via the recurrent layers. The AffWildNet produced state-of-the-art results on the Aff-Wild Challenge. We then exploit the AffWild database for learning features, which can be used as priors for achieving best performances both for dimensional, as well as categorical emo- tion recognition, using the RECOLA, AFEW-VA and EmotiW 2017 datasets, compared to all other methods designed for the same goal. The database and emotion recognition models are available at http://ibug.doc.ic.ac.uk/resources/first-affect-wild-challenge
Tensors, non-Gaussianities, and the future of potential reconstruction
We present projections for reconstruction of the inflationary potential
expected from ESA's upcoming Planck Surveyor CMB mission. We focus on the
effects that tensor perturbations and the presence of non-Gaussianities have on
reconstruction efforts in the context of non-canonical inflation models. We
consider potential constraints for different combinations of
detection/null-detection of tensors and non-Gaussianities. We perform Markov
Chain Monte Carlo and flow analyses on a simulated Planck-precision data set to
obtain constraints. We find that a failure to detect non-Gaussianities
precludes a successful inversion of the primordial power spectrum, greatly
affecting uncertainties, even in the presence of a tensor detection. In the
absence of a tensor detection, while unable to determine the energy scale of
inflation, an observable level of non-Gaussianities provides correlations
between the errors of the potential parameters, suggesting that constraints
might be improved for suitable combinations of parameters. Constraints are
optimized for a positive detection of both tensors and non-Gaussianities.Comment: 12 pages, 5 figures, LaTeX; V2: version submitted to JCA
Stochastic Inflation Revisited: Non-Slow Roll Statistics and DBI Inflation
Stochastic inflation describes the global structure of the inflationary
universe by modeling the super-Hubble dynamics as a system of matter fields
coupled to gravity where the sub-Hubble field fluctuations induce a stochastic
force into the equations of motion. The super-Hubble dynamics are ultralocal,
allowing us to neglect spatial derivatives and treat each Hubble patch as a
separate universe. This provides a natural framework in which to discuss
probabilities on the space of solutions and initial conditions. In this article
we derive an evolution equation for this probability for an arbitrary class of
matter systems, including DBI and k-inflationary models, and discover
equilibrium solutions that satisfy detailed balance. Our results are more
general than those derived assuming slow roll or a quasi-de Sitter geometry,
and so are directly applicable to models that do not satisfy the usual slow
roll conditions. We discuss in general terms the conditions for eternal
inflation to set in, and we give explicit numerical solutions of highly
stochastic, quasi-stationary trajectories in the relativistic DBI regime.
Finally, we show that the probability for stochastic/thermal tunneling can be
significantly enhanced relative to the Hawking-Moss instanton result due to
relativistic DBI effects.Comment: 38 pages, 2 figures. v3: minor revisions; version accepted into JCA
FRW Cosmology with Non-positively Defined Higgs Potentials
We discuss the classical aspects of dynamics of scalar models with
non-positive Higgs potentials in the FRW cosmology. These models appear as
effective local models in non-local models related with string field theories.
After a suitable field redefinition these models have the form of local Higgs
models with a negative extra cosmological term and the total Higgs potential is
non-positively defined and has rather small coupling constant. The
non-positivity of the potential leads to the fact that on some stage of
evolution the expansion mode gives place to the mode of contraction, due to
that the stage of reheating is absent. In these models the hard regime of
inflation gives place to inflation near the hill top and the area of the slow
roll inflation is very small. Meanwhile one can obtain enough e-foldings before
the contraction to make the model under consideration admissible to describe
inflation.Comment: 40 pages, 20 figures, typos correcte
Single-field inflation constraints from CMB and SDSS data
We present constraints on canonical single-field inflation derived from WMAP
five year, ACBAR, QUAD, BICEP data combined with the halo power spectrum from
SDSS LRG7. Models with a non-scale-invariant spectrum and a red tilt n_s < 1
are now preferred over the Harrison-Zel'dovich model (n_s = 1, tensor-to-scalar
ratio r = 0) at high significance. Assuming no running of the spectral indices,
we derive constraints on the parameters (n_s, r) and compare our results with
the predictions of simple inflationary models. The marginalised credible
intervals read n_s = 0.962^{+0.028}_{-0.026} and r < 0.17 (at 95% confidence
level). Interestingly, the 68% c.l. contours favour mainly models with a convex
potential in the observable region, but the quadratic potential model remains
inside the 95% c.l. contours. We demonstrate that these results are robust to
changes in the datasets considered and in the theoretical assumptions made. We
then consider a non-vanishing running of the spectral indices by employing
different methods, non-parametric but approximate, or parametric but exact.
With our combination of CMB and LSS data, running models are preferred over
power-law models only by a Delta chi^2 ~ 5.8, allowing inflationary stages
producing a sizable negative running -0.063^{+0.061}_{-0.049} and larger
tensor-scalar ratio r < 0.33 at the 95% c.l. This requires large values of the
third derivative of the inflaton potential within the observable range. We
derive bounds on this derivative under the assumption that the inflaton
potential can be approximated as a third order polynomial within the observable
range.Comment: 32 pages, 7 figures. v2: additional references, some typos corrected,
passed to JCAP style. v3: minor changes, matches published versio
Swordfish bill injury involving abdomen and vertebral column: case report and review
<p>Abstract</p> <p>Background</p> <p>Penetrating injuries of the abdomen and spinal canal that involve organic material of animal origin are extremely rare and derive from domestic and wild animal attacks or fish attacks.</p> <p>Case presentation</p> <p>In this case report we present the unique, as far as the literature is concerned, unprovoked woman's injury to the abdomen by a swordfish. There are only four cases of swordfish attacks on humans in the literature - one resulted to thoracic trauma, two to head trauma and one to knee trauma, one of which was fatal - none of which were unprovoked. Three victims were professional or amateur fishermen whereas in the last reported case the victim was a bather as in our case. Our case is the only case where organic debris of animal's origin remained in the spinal canal after penetrating trauma.</p> <p>Conclusions</p> <p>Although much has been written about the management of penetrating abdominal and spinal cord trauma, controversy remains about the optimal management. Moreover, there is little experience in the management of patients with such spinal injuries, due to the fact that such cases are extremely rare. In this report we focus on the patient's treatment with regard to abdominal and spinal trauma and present a review of the literature.</p
Non-relativistic Matrix Inflation
We reconsider a string theoretic inflationary model, where inflation is
driven by multiple coincident -branes in the finite limit. We show
that the finite action can be continued to the limit of large , where it
converges to the action for a wrapped -brane with units of U(1) flux.
This provides an important consistency check of the scenario and allows for
more control over certain back-reaction effects. We determine the most general
form of the action for a specific sub-class of models and examine the
non-relativistic limits of the theory where the branes move at speeds much less
than the speed of light. The non-Abelian nature of the world-volume theory
implies that the inflaton field is matrix valued and this results in
modifications to the slow-roll parameters and Hubble-flow equations. A specific
small field model of inflation is investigated where the branes move out of an
AdS throat, and observational constraints are employed to place bounds on the
background fluxes.Comment: 25 page
Structure modulated charge transfer in carbon atomic wires
sp-Hybridized carbon atomic wires are appealing systems with large property tunability. In particular, their electronic properties are intimately related to length, structure, and type of functional end-groups as well as to other effects such as the intermolecular charge transfer with metal nanoparticles. Here, by a combined Raman, Surface Enhanced Raman Scattering (SERS) investigation and first principles calculations of different N,N-dimethylanilino-terminated polyynes, we suggest that, upon charge transfer interaction with silver nanoparticles, the function of sp-carbon atomic wire can change from electron donor to electron acceptor by increasing the wire length. In addition, the insertion into the wire of a strong electrophilic group (1,1,4,4-tetracyanobuta-1,3-diene-2,3-diyl) changes the electron-accepting molecular regions involved in this intermolecular charge transfer. Our results indicate that carbon atomic wires could display a tunable charge transfer between the sp-wire and the metal, and hold promise as active materials in organic optoelectronics and photovoltaics
Synthesis of trans-A(2)B(2)- and trans-A(2)BC-Porphyrins with Polar 4 '-(Dimethylamino)tolan-4-yl Substituents, and a Screening Protocol for Vapor-Phase Deposition on Metal Surfaces
The role of polar 4-[p-(dimethylamino) phenylethynyl] phenyl substituents, with a calculated dipole moment of 3.35 Debye, in the self-assembly of trans-A(2)B(2)- and A(2)BC-substituted porphyrins was explored in the solid state by X-ray crystallography, and on an Au(111) surface by scanning tunneling microscopy (STM). Our results demonstrate that the dipolar character of these substituents blocks the 2D self-assembly of porphyrins into larger ordered domains on Au(111) at low coverage, whereas antiparallel dipole-dipole interactions govern the molecular ordering in the crystal. The STM analysis revealed an adaptation of the conformation of the prochiral building blocks and a site-selectivity of the adsorption. We present a general protocol for testing the suitability of higher-molecular-weight compounds, such as porphyrins, to be deposited on surface by sublimation in ultra-high vacuum (UHV). This protocol combines classical methods of chemical analysis with typical surface science techniques
Polymorphism control of superconductivity and magnetism in Cs3C60 close to the Mott transition
The crystal structure of a solid controls the interactions between the electronically active units and thus its electronic properties. In the high-temperature superconducting copper oxides, only one spatial arrangement of the electronically active Cu2+ units—a two-dimensional square lattice—is available to study the competition between the cooperative electronic states of magnetic order and superconductivity1. Crystals of the spherical molecular C603- anion support both superconductivity and magnetism but can consist of fundamentally distinct three-dimensional arrangements of the anions. Superconductivity in the A3C60 (A = alkali metal) fullerides has been exclusively associated with face-centred cubic (f.c.c.) packing of C603- (refs 2, 3), but recently the most expanded (and thus having the highest superconducting transition temperature, Tc; ref. 4) composition Cs3C60 has been isolated as a body-centred cubic (b.c.c.) packing, which supports both superconductivity and magnetic order5, 6. Here we isolate the f.c.c. polymorph of Cs3C60 to show how the spatial arrangement of the electronically active units controls the competing superconducting and magnetic electronic ground states. Unlike all the other f.c.c. A3C60 fullerides, f.c.c. Cs3C60 is not a superconductor but a magnetic insulator at ambient pressure, and becomes superconducting under pressure. The magnetic ordering occurs at an order of magnitude lower temperature in the geometrically frustrated f.c.c. polymorph (Néel temperature TN = 2.2 K) than in the b.c.c.-based packing (TN = 46 K). The different lattice packings of C603- change Tc from 38 K in b.c.c. Cs3C60 to 35 K in f.c.c. Cs3C60 (the highest found in the f.c.c. A3C60 family). The existence of two superconducting packings of the same electronically active unit reveals that Tc scales universally in a structure-independent dome-like relationship with proximity to the Mott metal–insulator transition, which is governed by the role of electron correlations characteristic of high-temperature superconducting materials other than fullerides