Institut Néel

Reproductive health is the absence of illness or disability related to the reproductive system and its functions, and mental and social well-being.Reproductive health also means that people have a satisfying and safe sexual life, have the ability to reproduce, and have the freedom to decide whether to use their reproductive ability.This issue is often ignored for menopausal and post-menopausal older women, whose fertility is over.However, reproductive health should be regarded as the fundamental right of all men and women, young and old people.In this review, we aimed to address the problems of reproductive health of over 50 years old and older women.

Electromagnetically induced transparency is a quantum interference effect observed in atoms and molecules, in which the optical response of an atomic medium is controlled by an electromagnetic field. We demonstrated a form of induced transparency enabled by radiation-pressure coupling of an optical and a mechanical mode. A control optical beam tuned to a sideband transition of a micro-optomechanical system leads to destructive interference for the excitation of an intracavity probe field, inducing a tunable transparency window for the probe beam. Optomechanically induced transparency may be used for slowing and on-chip storage of light pulses via microfabricated optomechanical arrays.

An experimental method based on the Landau-Zener model was developed to measure very small tunnel splittings in molecular clusters of eight iron atoms, which at low temperature behave like a nanomagnet with a spin ground state of S = 10. The observed oscillations of the tunnel splittings as a function of the magnetic field applied along the hard anisotropy axis are due to topological quantum interference of two tunnel paths of opposite windings. Transitions between quantum numbers M = -S and (S - n), with n even or odd, revealed a parity effect that is analogous to the suppression of tunneling predicted for half-integer spins. This observation is direct evidence of the topological part of the quantum spin phase (Berry phase) in a magnetic system.

A large electric field at the surface of a ferromagnetic metal is expected to appreciably change its electron density. In particular, the metal's intrinsic magnetic properties, which are commonly regarded as fixed material constants, will be affected. This requires, however, that the surface has a strong influence on the material's properties, as is the case with ultrathin films. We demonstrated that the magnetocrystalline anisotropy of ordered iron-platinum (FePt) and iron-palladium (FePd) intermetallic compounds can be reversibly modified by an applied electric field when immersed in an electrolyte. A voltage change of -0.6 volts on 2-nanometer-thick films altered the coercivity by -4.5 and +1% in FePt and FePd, respectively. The modification of the magnetic parameters was attributed to a change in the number of unpaired d electrons in response to the applied electric field. Our device structure is general and should be applicable for characterization of other thin-film magnetic systems.

We present the all-sky Planck catalogue of Sunyaev-Zeldovich (SZ) sources detected from the 29 month full-mission data. The catalogue (PSZ2) is the largest SZ-selected sample of galaxy clusters yet produced and the deepest systematic all-sky surveyof galaxy clusters. It contains 1653 detections, of which 1203 are confirmed clusters with identified counterparts in external data sets, and is the first SZ-selected cluster survey containing >103 confirmed clusters. We present a detailed analysis of the survey selection function in terms of its completeness and statistical reliability, placing a lower limit of 83% on the purity. Using simulations, we find that the estimates of the SZ strength parameter Y5R500are robust to pressure-profile variation and beam systematics, but accurate conversion to Y500 requires the use of prior information on the cluster extent. We describe the multi-wavelength search for counterparts in ancillary data, which makes use of radio, microwave, infra-red, optical, and X-ray data sets, and which places emphasis on the robustness of the counterpart match. We discuss the physical properties of the new sample and identify a population of low-redshift X-ray under-luminous clusters revealed by SZ selection. These objects appear in optical and SZ surveys with consistent properties for their mass, but are almost absent from ROSAT X-ray selected samples.

Single-molecule magnets (SMMs) with a large spin reversal barrier have been recognized to exhibit slow magnetic relaxation that can lead to a magnetic hysteresis loop. Synthesis of highly stable SMMs with both large energy barriers and significantly slow relaxation times is challenging. Here, we report two highly stable and neutral Dy(III) classical coordination compounds with pentagonal bipyramidal local geometry that exhibit SMM behavior. Weak intermolecular interactions in the undiluted single crystals are first observed for mononuclear lanthanide SMMs by micro-SQUID measurements. The investigation of magnetic relaxation reveals the thermally activated quantum tunneling of magnetization through the third excited Kramers doublet, owing to the increased axial magnetic anisotropy and weaker transverse magnetic anisotropy. As a result, pronounced magnetic hysteresis loops up to 14 K are observed, and the effective energy barrier (Ueff = 1025 K) for relaxation of magnetization reached a breakthrough among the SMMs.

Because the refractive index for hard x rays is slightly different from unity, the optical phase of a beam is affected by transmission through an object. Phase images can be obtained with extreme instrumental simplicity by simple propagation provided the beam is coherent. But, unlike absorption, the phase is not simply related to image brightness. A holographic reconstruction procedure combining images taken at different distances from the specimen was developed. It results in quantitative phase mapping and, through association with three-dimensional reconstruction, in holotomography, the complete three-dimensional mapping of the density in a sample. This tool in the characterization of materials at the micrometer scale is uniquely suited to samples with low absorption contrast and radiation-sensitive systems.

The European Space Agency’s Planck satellite, which is dedicated to studying the early Universe and its subsequent evolution, was launched on 14 May 2009. It scanned the microwave and submillimetre sky continuously between 12 August 2009 and 23 October 2013. In February 2015, ESA and the Planck Collaboration released the second set of cosmology products based ondata from the entire Planck mission, including both temperature and polarization, along with a set of scientific and technical papers and a web-based explanatory supplement. This paper gives an overview of the main characteristics of the data and the data products in the release, as well as the associated cosmological and astrophysical science results and papers. The data products include maps of the cosmic microwave background (CMB), the thermal Sunyaev-Zeldovich effect, diffuse foregrounds in temperature and polarization, catalogues of compact Galactic and extragalactic sources (including separate catalogues of Sunyaev-Zeldovich clusters and Galactic cold clumps), and extensive simulations of signals and noise used in assessing uncertainties and the performance of the analysis methods. The likelihood code used to assess cosmological models against the Planck data is described, along with a CMB lensing likelihood. Scientific results include cosmological parameters derived from CMB power spectra, gravitational lensing, and cluster counts, as well as constraints on inflation, non-Gaussianity, primordial magnetic fields, dark energy, and modified gravity, and new results on low-frequency Galactic foregrounds.

We report the results of a joint analysis of data from BICEP2/Keck Array and Planck. BICEP2 and Keck Array have observed the same approximately 400 deg^{2} patch of sky centered on RA 0 h, Dec. -57.5°. The combined maps reach a depth of 57 nK deg in Stokes Q and U in a band centered at 150 GHz. Planck has observed the full sky in polarization at seven frequencies from 30 to 353 GHz, but much less deeply in any given region (1.2 μK deg in Q and U at 143 GHz). We detect 150×353 cross-correlation in B modes at high significance. We fit the single- and cross-frequency power spectra at frequencies ≥150 GHz to a lensed-ΛCDM model that includes dust and a possible contribution from inflationary gravitational waves (as parametrized by the tensor-to-scalar ratio r), using a prior on the frequency spectral behavior of polarized dust emission from previous Planck analysis of other regions of the sky. We find strong evidence for dust and no statistically significant evidence for tensor modes. We probe various model variations and extensions, including adding a synchrotron component in combination with lower frequency data, and find that these make little difference to the r constraint. Finally, we present an alternative analysis which is similar to a map-based cleaning of the dust contribution, and show that this gives similar constraints. The final result is expressed as a likelihood curve for r, and yields an upper limit r_{0.05}<0.12 at 95% confidence. Marginalizing over dust and r, lensing B modes are detected at 7.0σ significance.

A meeting of two magnetic worlds: The giant (ca. 4.2 nm) {Mn84} cluster, shown, has a torus structure and is a single-molecule magnet (SMM). It represents a meeting of the molecular (bottom-up) and classical (top-down) approaches to nanoscale magnetic materials, and it crystallizes as nanotubular stacks. The discovery that individual molecules can function as magnets provided a new, “bottom-up” approach to nanoscale magnetic materials,1–3 and such molecules have since been called single-molecule magnets (SMMs).4 Each molecule is a single-domain magnetic particle that, below its blocking temperature, exhibits the classical macroscale property of a magnet, namely magnetization hysteresis. In addition, SMMs straddle the classical/quantum interface in also displaying quantum tunneling of magnetization (QTM)5, 6 and quantum phase interference,7 which are the properties of the microscale. SMMs have various potential applications, including very high-density information storage with each bit stored as the magnetization orientation of an individual molecule, and as quantum bits for quantum computing8 by taking advantage of the quantum superposition of states provided by the QTM. For a number of reasons, including facilitating development of techniques for addressing individual SMMs, we have sought to synthesize SMMs of very-large dimensions (by molecular standards). In effect, can the molecular (or bottom-up) approach reach the size regime of the classical (or top-down) approach to nanoscale magnetic materials? Indeed, herein we report a giant Mn84 SMM. It has a 4 nm diameter torus structure, exhibits both magnetization hysteresis and QTM, and crystallizes as supramolecular nanotubes. The compound [Mn84O72(O2CMe)78(OMe)24(MeOH)12(H2O)42(OH)6]⋅x H2O⋅y CHCl3 (1⋅x H2O⋅y CHCl3) was obtained from the reaction of [Mn12O12(O2CMe)16(H2O)4]⋅4 H2O⋅2 MeCO2H (2) with (NnBu4)(MnO4) in MeOH that contained a little acetic acid, followed by filtration and layering of the filtrate with chloroform. After several weeks, the well-formed reddish-brown crystals were isolated in a 20 % overall yield, based on the total available Mn equivalents. The compound crystallizes in hexagonal space group P6 with the asymmetric unit containing 1/6 of the molecule and approximately 25 water and 2 chloroform solvent molecules of crystallization, which are severely disordered. The structure9 (Figure 1) comprises a {Mn84} torus with C6 crystallographic symmetry composed of alternating near-linear [Mn3O4] and cubic [Mn4O2(OMe)2] subunits. All the metal centers are six-coordinate. Close inspection of the MnO bond lengths, the Mn bond valence sum calculations (2.82–3.26),10 and the detection of Jahn–Teller axial elongations as expected for a d4 metal ion in near-octahedral geometry, identified the metal ions as all being in the Mn3+ oxidation state. The structure of the {Mn84} torus, excluding hydrogen atoms. The rectangle shows the repeating {Mn14} unit that represents the contents of the asymmetric unit; for clarity, it is reproduced above the structure without the carbon atoms (except for those of the MeO− groups to clarify their positions in the {Mn14} unit). Colour code: Mn blue; O red; C grey. A better appreciation of the structure and the size of the molecule is provided by the space-filling plots of Figure 2, which show that the torus has a diameter of about 4.2 nm and a thickness of about 1.2 nm, with a central hole of diameter 1.9 nm. The Mn84 molecules order within the crystal in an aesthetically pleasing manner, thus giving nanotubular stacks parallel to the crystal c axis and to their neighbors (Figures 2 b,c2). This yields a hexagonal close packing analogous to densely packed straws in a box. The crystalline structure of Mn84 thus displays extensive cylindrical channel formation along one dimension. Molecules in neighboring chains are exactly adjacent (Figure 2 b), and thus the structure may be alternatively described as consisting of graphite-like {Mn84} sheets lying on top of each other with perfect registry. Space-filling representations of {Mn84}, and its supramolecular aggregation into ordered nanotubes and sheets. a) Space-filling representations (including hydrogen atoms) from viewpoints perpendicular (top) and parallel (bottom) to the plane of the torus, showing the dimensions of the molecule and its central hole. b) Ordered arrangement of {Mn84} molecules (excluding hydrogen atoms) into two adjacent supramolecular nanotubes viewed perpendicular to the propagation axis; this view emphasizes the exact registry of molecules in adjacent tubes and thus the sheetlike structure formed. c) A view along the propagation axes of seven tubes showing the hexagonal packing of neighbors within a single sheet of molecules (excluding hydrogen atoms). Color code: Mn blue; O red; C grey; H white. The magnetic properties of {Mn84} have been investigated by both DC and AC methods. The molecule comprises eighty-four Mn3+ ions (S=2), and it was anticipated that there would be fairly strong pairwise exchange interactions between them because they are all monoatomically bridged by O2− or MeO− groups. Preliminary magnetic susceptibility (χM) studies on polycrystalline samples down to 1.8 K indicated a small uncompensated molecular spin of S≈6. In the presence of sufficient magnetic anisotropy of the easy axis (Ising) type, a spin of this magnitude is sufficient to provide a SMM, and more detailed studies to lower temperatures were therefore carried out to investigate this possibility. Studies were performed by magnetization measurements on single crystals of {Mn84} by using an array of micro-SQUIDs (SQUID is superconducting quantum interference device). 11 The magnetization versus applied DC field at a 0.035 T s−1 sweep rate (Figure 3 a) exhibited hysteresis, which is the diagnostic property of a magnet, thus establishing {Mn84} as the largest SMM yet discovered. At this sweep rate, the hysteresis becomes evident at 1.5 K, and its coercivity increases with decreasing temperature, as expected for the superparamagnet-like properties of an SMM, before becoming essentially temperature-independent below 0.3 K. The magnetization in Figure 3 a is plotted as spin (S) per molecule (determined by using quantitative molar magnetization data). The saturation value indicates a molecular ground state spin of S=6, thus confirming the preliminary estimate above. The hysteresis loop shows no sign of the steps diagnostic of QTM that are visible in the hysteresis loops of several smaller SMMs such as {Mn12},5, 6 {Mn4},12, 13 and {Fe8},7, 14 and the exchange-biased {(Mn4)2} dimer.15 In previous cases in which no steps are visible, for large SMMs such as the {Mn18}2+16 and {Mn30}17 SMMs, this lack of visible steps is due to a broadening and smearing of the steps from low-lying excited states and a distribution of molecular environments (and thus a distribution of relaxation barriers) caused by disordered lattice solvent molecules and ligand disorder; the magnetic properties of SMMs are sensitive to such relatively small variations in local environments. For {Mn84}, the large numbers of disordered solvent molecules in the central cavity readily rationalize a distribution of molecular environments. The results of magnetic susceptibility studies on single crystals of {Mn84}. a) Magnetization versus applied DC magnetic field plots, with the field applied along the c axis (perpendicular to the {Mn84} torus plane), exhibiting hysteresis loops. The magnetization has been plotted as spin (S) per {Mn84} molecule. A background slope due to low-lying excited states has been subtracted from the data. b) Arrhenius plot constructed by using a combination of out-of-phase AC susceptibility (χM′′) data and DC magnetization decay data. The dashed line is a fit of the thermally activated region to the Arrhenius relationship; see the text for the fit parameters. The relaxation rate levels off below 0.5 K, and below about 0.2 K it is temperature-independent, which is consistent with relaxation only by ground-state tunneling between the lowest energy MS=±6 levels of the S=6 manifold. Such temperature-independent relaxation rates arising from QTM have been observed previously for several other SMMs.12–14, 16–18 Independent conformation of QTM in {Mn84} was obtained from “quantum hole digging”,19 which can establish resonant QTM even when no steps are apparent in the hysteresis loops. It is thus clear that {Mn84} still exhibits the quantum behavior that has become a common feature of the much smaller SMMs. The above results establish {Mn84} as a giant SMM. In general, SMMs have many advantages over classical magnetic particles made of Co metal, Fe3O4, etc., including monodispersity, crystallization as highly ordered ensembles, true solubility (rather than colloidal suspensions), and a shell of organic groups that protects the magnetic cores from surface variations and prevents their contact with each other. The discovery of a {Mn84} SMM establishes that these advantages can also be extended to this giant molecule, which is still soluble, stable, and crystalline. Such large wheel-like molecules are with precedent, but only in molybdenum chemistry,20 with the largest currently known being the {Mo154}21 and {Mo176}22 compounds prepared by Müller and co-workers. Although they contain more metal atoms than {Mn84}, the {Mo154} and {Mo176} wheels have diameters of about 3.4 and about 4.1 nm, respectively. These, and other giant polyoxometallates,23–25 are diamagnetic or nearly so, and none of them exhibit SMM properties. But although {Mn84} is very large by molecular standards, it is pertinent to ask how it compares to classical nanoparticles. In Figure 4 the sizes of {Mn4}, {Mn12}, {Mn30}, and {Mn84} SMMs are compared with that of a 3 nm Co nanoparticle recently reported,26 all drawn to the same scale. With a 4.2 nm diameter, {Mn84} is thus of comparable size to the smallest nanoparticles. The total number of atoms in {Mn84} is 1032, roughly the same as the 3 nm Co nanoparticle, which contains about 1000 Co atoms. Of course, the former has a very different shape, given its central hole and essentially wheel-like rather than spherical structure. Another useful way, particularly in the physics literature, of comparing the “size” of magnetic systems is by their Néel vector (N, the sum of the individual spins), which are 7.5, 22, 61, and 168 for {Mn4}, {Mn12}, {Mn30}, and {Mn84}, respectively. This is the scale used in Figure 4. With a value of 168, {Mn84} is a far larger spin system than any other molecular cluster (greater than the next largest, 75, observed previously for an Fe30 species with S=024, 25) and is at the lower limit of values found for classical nanoparticles, which can range from a few hundred to many thousands, depending on the precise size and constituent metal; for the 3 nm Co nanoparticle shown, the Néel vector is approximately 1000. The position of {Mn84} on a size scale spanning atomic to nanoscale dimensions. On the far right is shown a high-resolution transmission electron microscopy view along a [110] direction of a typical 3 nm diameter cobalt nanoparticle exhibiting a face-centered cubic structure and containing about 1000 Co atoms.26 The {Mn84} molecule is a 4.2 nm diameter particle. Also shown for comparison are the indicated smaller Mn SMMs, which are drawn to scale. An alternative means of comparison is the Néel vector (N), which is the scale shown. The green arrows indicate the magnitude of the Néel vectors for the indicated SMMs, which are 7.5, 22, 61, and 168 for {Mn4}, {Mn12}, {Mn30} and {Mn84}, respectively. The green arrows from the Co nanoparticle are merely meant to indicate that the Néel vector of nanoparticles can take many values, depending on the exact size and the identity of the constituent metal. The new {Mn84} SMM thus essentially represents a long-sought-after meeting of the bottom-up and top-down approaches to nanoscale magnetic materials. It will be interesting to see whether even larger SMMs that contain more metal atoms can be obtained in the near future; we see no reason why this should not be so. It is also interesting that {Mn84} exhibits magnetization quantum tunneling, a point of relevance to the general question of how large magnetic nanoparticles can become and still display quantum effects.27 Such studies for classical magnetic nanoparticles have been hampered by complications from distributions of particle size, shape, surface roughness, and spin11, 28 a problem that does not exist for crystalline, monodisperse SMMs. Finally, we recognize that the supramolecular architecture of the {Mn84} molecules as ordered nanotubular stacks offers a variety of future possibilities for accessing interesting new materials, including the insertion of guest molecules (either organic or inorganic, diamagnetic or paramagnetic) or chains (either conducting or insulating) into or through the tubes. In addition, the large shape anisotropy and solubility of {Mn84} suggest that it should be fairly straightforward to deposit and visualize these molecular rings on surfaces. Compound 1: A freshly-prepared solution of NnBu4MnO4 (0.30 g, 0.83 mmol) in MeOH (10 mL) and glacial acetic acid (0.75 ml) was added to a slurry of [Mn12O12(O2CMe)16(H2O)4]⋅4 H2O⋅2 HO2CMe (0.425 g, 0.206 mmol) in MeOH (15 mL) over a period of two minutes. The mixture was left under magnetic stirring for a few minutes, and then filtered to give a reddish-brown filtrate. Equal amounts of the filtrate were placed in five different vials and layered with chloroform. After a few weeks reddish-brown crystals appeared, and were left to grow for several more weeks to give well shaped X-rays quality crystals. When product formation was deemed to be complete, the crystals were collected by filtration, washed with chloroform and dried in vacuum. The yield was 0.10 g (20 % based on total Mn). Elemental analysis (%) calcd for C192H464O322Mn84 (1⋅10 H2O): C 18.39, H 3.73; found: C 18.35, H 3.45. Selected IR data (KBr pellet): =3400(s, br), 2965(w), 2931(w), 1576(s, br), 1527(s, br), 1425(s, br), 1348(m), 1250(w), 1028(m), 949(w), 696(m), 666(s), 623(s), 580(s), 548(s), 506(m).

Roll the Dy's: Two aggregates made up of dysprosium triangles (one example is shown) display a vanishing susceptibility at low temperature, unprecedented in systems comprising an odd number of unpaired electrons. Despite having a near non-magnetic ground state, behavior typical of a single-molecule magnet is observed for the thermally populated excited state.

Phase objects are readily imaged through Fresnel diffraction in the hard x-ray beams of third-generation synchrotron radiation sources such as the ESRF, due essentially to the very small angular size of the source. Phase objects can lead to spurious contrast in x-ray diffraction images (topographs) of crystals. It is shown that this contrast can be eliminated through random phase plates, which provide an effective way of tailoring the angular size of the source. The possibilities of this very simple technique for imaging phase objects in the hard x-ray range are explored experimentally and discussed. They appear very promising, as shown in particular by the example of a piece of human vertebra, and could be extended to phase tomography.

Recent advances in addressing isolated nuclear spins have opened up a path toward using nuclear-spin-based quantum bits. Local magnetic fields are normally used to coherently manipulate the state of the nuclear spin; however, electrical manipulation would allow for fast switching and spatially confined spin control. Here, we propose and demonstrate coherent single nuclear spin manipulation using electric fields only. Because there is no direct coupling between the spin and the electric field, we make use of the hyperfine Stark effect as a magnetic field transducer at the atomic level. This quantum-mechanical process is present in all nuclear spin systems, such as phosphorus or bismuth atoms in silicon, and offers a general route toward the electrical control of nuclear-spin-based devices.

We show experimentally that multilayer graphene grown on the carbon terminated SiC(0001[over ]) surface contains rotational stacking faults related to the epitaxial condition at the graphene-SiC interface. Via first-principles calculation, we demonstrate that such faults produce an electronic structure indistinguishable from an isolated single graphene sheet in the vicinity of the Dirac point. This explains prior experimental results that showed single-layer electronic properties, even for epitaxial graphene films tens of layers thick.

A strong substrate-graphite bond is found in the first all-carbon layer by density functional theory calculations and x-ray diffraction for few graphene layers grown epitaxially on SiC. This first layer is devoid of graphene electronic properties and acts as a buffer layer. The graphene nature of the film is recovered by the second carbon layer grown on both the (0001) and (0001[over]) 4H-SiC surfaces. We also present evidence of a charge transfer that depends on the interface geometry. Hence the graphene is doped and a gap opens at the Dirac point after three Bernal stacked carbon layers are formed.

The high axiality and Ising exchange interaction efficiently suppress quantum tunneling of magnetization of an asymmetric dinuclear Dy(III) complex, as revealed by combined experimental and theoretical investigations. Two distinct regimes of blockage of magnetization, one originating from the blockage at individual Dy sites and the other due to the exchange interaction between the sites, are separated for the first time. The latter contribution is found to be crucial, allowing an increase of the relaxation time by 3 orders of magnitude.

For Dirac electrons the Klein paradox implies that the confinement is difficult to achieve with an electrostatic potential although it can be of great importance for graphene-based devices. Here, ab initio and tight-binding approaches are combined and show that the wave function of Dirac electrons can be localized in rotated graphene bilayers due to the Moire pattern. This localization of wave function is maximum in the limit of the small rotation angle between the two layers.

Isolated hydrogen atoms absorbed on graphene are predicted to induce magnetic moments. Here we demonstrate that the adsorption of a single hydrogen atom on graphene induces a magnetic moment characterized by a ~20-millielectron volt spin-split state at the Fermi energy. Our scanning tunneling microscopy (STM) experiments, complemented by first-principles calculations, show that such a spin-polarized state is essentially localized on the carbon sublattice opposite to the one where the hydrogen atom is chemisorbed. This atomically modulated spin texture, which extends several nanometers away from the hydrogen atom, drives the direct coupling between the magnetic moments at unusually long distances. By using the STM tip to manipulate hydrogen atoms with atomic precision, it is possible to tailor the magnetism of selected graphene regions.

We implemented a self-consistent, real-space x-ray absorption calculation within the FDMNES code. We performed the self-consistency within several schemes and identified which one is the most appropriate. We show a method that allows a rigorous setting of the Fermi level and thus an estimation of the energy cutoff for the identification and elimination of the occupied states. We investigated what are the structures where one can afford performing the self-consistent calculation at a lesser cluster radius than the absorption one. We exemplify the effects of the self-consistency at the K-edge and for several reference cases, including the copper Cu and the rutile TiO(2). We verified the robustness of our procedure on the transitional 3d and 4d elements. Although amelioration can be noticed, the self-consistency performed at the K-edge does not bring a major improvement of the calculated spectra. Taking into consideration a non-self-consistent, non-spherical potential gives better results than a self-consistent muffin-tin approximation calculation.

This work targets human action recognition in video. While recent methods typically represent actions by statistics of local video features, here we argue for the importance of a representation derived from human pose. To this end we propose a new Pose-based Convolutional Neural Network descriptor (P-CNN) for action recognition. The descriptor aggregates motion and appearance information along tracks of human body parts. We investigate different schemes of temporal aggregation and experiment with P-CNN features obtained both for automatically estimated and manually annotated human poses. We evaluate our method on the recent and challenging JHMDB and MPII Cooking datasets. For both datasets our method shows consistent improvement over the state of the art.