Infant cortex responds to other humans from shortly after birth

A significant feature of the adult human brain is its ability to selectively process information about conspecifics. Much debate has centred on whether this specialization is primarily a result of phylogenetic adaptation, or whether the brain acquires expertise in processing social stimuli as a result of its being born into an intensely social environment. Here we study the haemodynamic response in cortical areas of newborns (1–5 days old) while they passively viewed dynamic human or mechanical action videos. We observed activation selective to a dynamic face stimulus over bilateral posterior temporal cortex, but no activation in response to a moving human arm. This selective activation to the social stimulus correlated with age in hours over the first few days post partum. Thus, even very limited experience of face-to-face interaction with other humans may be sufficient to elicit social stimulus activation of relevant cortical regions

Mean first-passage times of non-Markovian random walkers in confinement

The first-passage time (FPT), defined as the time a random walker takes to reach a target point in a confining domain, is a key quantity in the theory of stochastic processes. Its importance comes from its crucial role to quantify the efficiency of processes as varied as diffusion-limited reactions, target search processes or spreading of diseases. Most methods to determine the FPT properties in confined domains have been limited to Markovian (memoryless) processes. However, as soon as the random walker interacts with its environment, memory effects can not be neglected. Examples of non Markovian dynamics include single-file diffusion in narrow channels or the motion of a tracer particle either attached to a polymeric chain or diffusing in simple or complex fluids such as nematics \cite{turiv2013effect}, dense soft colloids or viscoelastic solution. Here, we introduce an analytical approach to calculate, in the limit of a large confining volume, the mean FPT of a Gaussian non-Markovian random walker to a target point. The non-Markovian features of the dynamics are encompassed by determining the statistical properties of the trajectory of the random walker in the future of the first-passage event, which are shown to govern the FPT kinetics.This analysis is applicable to a broad range of stochastic processes, possibly correlated at long-times. Our theoretical predictions are confirmed by numerical simulations for several examples of non-Markovian processes including the emblematic case of the Fractional Brownian Motion in one or higher dimensions. These results show, on the basis of Gaussian processes, the importance of memory effects in first-passage statistics of non-Markovian random walkers in confinement.Comment: Submitted version. Supplementary Information can be found on the Nature website : http://www.nature.com/nature/journal/v534/n7607/full/nature18272.htm

Phase Transitions in Zeolitic Imidazolate Framework 7: The Importance of Framework Flexibility and Guest-Induced Instability

A study of the phase transitions in ZIF-7 (zeolitic imidazolate frameworks- (Zn(PhIm)2, PhIm = benzimidazolate)) as a function of guest occupancy and temperature was reported. Raman spectra of an as-synthesized sample were collected in air between 297 and 421 K. The major contributions of the spectra come from the vibrational modes of the benzimidazolate ligand. Upon heating, most of the Raman bands remain similar and keep the same frequencies until 357 K, indicating that the structure of ZIF-7 seems to be stable in this temperature range. Above 357 K, strong modifications are observed in the regions corresponding to the lattice modes. The formation of ZIF-7-II is attributed to the loss of dimethylformamide (DMF) solvent molecules from the ZIF-7-I framework. This can be confirmed by the differential scanning calorimetry and thermogravimetric analysis traces of ZIF-7-I. The highly-distorted and locally-strained nature of ZIF-7-II leads to its poor crystallinity, reflected by X-ray powder diffraction and scanning electron microscope

Cellular Structures for Computation in the Quantum Regime

We present a new cellular data processing scheme, a hybrid of existing cellular automata (CA) and gate array architectures, which is optimized for realization at the quantum scale. For conventional computing, the CA-like external clocking avoids the time-scale problems associated with ground-state relaxation schemes. For quantum computing, the architecture constitutes a novel paradigm whereby the algorithm is embedded in spatial, as opposed to temporal, structure. The architecture can be exploited to produce highly efficient algorithms: for example, a list of length N can be searched in time of order cube root N.Comment: 11 pages (LaTeX), 3 figure

Nonlinear quantum mechanics implies polynomial-time solution for NP-complete and #P problems

If quantum states exhibit small nonlinearities during time evolution, then quantum computers can be used to solve NP-complete problems in polynomial time. We provide algorithms that solve NP-complete and #P oracle problems by exploiting nonlinear quantum logic gates. It is argued that virtually any deterministic nonlinear quantum theory will include such gates, and the method is explicitly demonstrated using the Weinberg model of nonlinear quantum mechanics.Comment: 10 pages, no figures, submitted to Phys. Rev. Let

Astrophysical Fluids of Novae: High Resolution Pre-decay X-ray spectrum of V4743 Sagittarii

Eight X-ray observations of V4743 Sgr (2002), observed with Chandra and XMM-Newton are presented. The nova turned off some time between days 301.9 and 371, and the X-ray flux subsequently decreased from day 301.9 to 526 following an exponential decline time scale of $(96 \pm 3)$ days. We use the absorption lines present in the SSS spectrum for diagnostic purposes, and characterize the physics and the dynamics of the expanding atmosphere during the explosion of the nova. The information extracted from this first stage is then used as input for computing full photoionization models of the ejecta in V4743 Sgr. The SSS spectrum is modeled with a simple black-body and multiplicative Gaussian lines, which provides us of a general kinematical picture of the system, before it decays to its faint phase (Ness et al. 2003). In the grating spectra taken between days 180.4 and 370, we can resolve the line profiles of absorption lines arising from H-like and He-like C, N, and O, including transitions involving higher principal quantum numbers. Except for a few interstellar lines, all lines are significantly blue-shifted, yielding velocities between 1000 and 6000 km/s which implies an ongoing mass loss. It is shown that significant expansion and mass loss occur during this phase of the explosion, at a rate $\dot{M} \approx (3-5) \times 10^{-4} ~ (\frac{L}{L_{38}}) ~ M_{\odot}/yr$. Our measurements show that the efficiency of the amount of energy used for the motion of the ejecta, defined as the ratio between the kinetic luminosity $L_{\rm kin}$ and the radiated luminosity $L_{\rm rad}$, is of the order of one.Comment: 25 pages, 9 figures. Accepted in book: Recent Advances in Fluid Dynamics with Environmental Applications, pp.365-39

Fundamental parameters of Cepheids. V. Additional photometry and radial velocity for southern Cepheids

I present photometric and radial velocity data for Galactic Cepheids, most of them being in the southern hemisphere. There are 1250 Geneva 7-color photometric measurements for 62 Cepheids, the average uncertainty per measurement is better than 0.01 mag. A total of 832 velocity measurements have been obtained with the CORAVEL radial velocity spectrograph for 46 Cepheids. The average accuracy of the radial velocity data is 0.38 km/s. There are 33 stars with both photometry and radial velocity data. I discuss the possible binarity or period change that these new data reveal. I also present reddenings for all Cepheids with photometry. The data are available electronically.Comment: To appear in ApJS. Data available electronically at ftp://cfa-ftp.harvard.edu/pub/dbersier

Adsorption site and orientation of pyridine on Cu{110} determined by photoelectron diffraction

The local adsorption geometry of pyridine on Cu{110} has been determined quantitatively using photoelectron diffraction in the scanned-energy mode. At high coverages the molecule adsorbs nearly atop a Cu atom in the close-packed rows with a N–Cu bond length of 2.00 Å. Moreover, the Cu–N axis and the molecular (C2) axis are inclined by 8° and 20°, respectively, to the surface normal. The result shows that not only the adsorption site of the emitter (in this case the N atom) but also the position of relatively light scatterers (the C atoms) can be determined by photoelectron diffraction