ShantanuT01/DACTYL-Pretraining huggingface dataset:
We obtain a representation theorem for Banach space valued Gaussian random variables as integrals against a white noise. As a corollary we obtain necessary and sufficient conditions for the existence of a white noise representation for a Gaussian random field indexed by a compact measure space. As an application we show how existing theory for integration with respect to Gaussian processes indexed by $[0,1]$ can be extended to Gaussian fields indexed by compact measure spaces.
We exhibit a non-hyperelliptic curve C of genus 3 such that the class of the Ceresa cycle [C]-[(-1)*C] in JC modulo algebraic equivalence is torsion.
The role of galactic wind recycling represents one of the largest unknowns in galaxy evolution, as any contribution of recycling to galaxy growth is largely degenerate with the inflow rates of first-time infalling material, and the rates with which outflowing gas and metals are driven from galaxies. We present measurements of the efficiency of wind recycling from the EAGLE cosmological simulation project, leveraging the statistical power of large-volume simulations that reproduce a realistic galaxy population. We study wind recycling at the halo scale, i.e. gas that has been ejected beyond the halo virial radius, and at the galaxy scale, i.e. gas that has been ejected from the ISM to at least $\approx 10 \, \%$ of the virial radius (thus excluding smaller-scale galactic fountains). Galaxy-scale wind recycling is generally inefficient, with a characteristic return timescale that is comparable or longer than a Hubble time, and with an efficiency that clearly peaks at the characteristic halo mass of $M_{200} = 10^{12} \, \mathrm{M_\odot}$. Correspondingly, the majority of gas being accreted onto galaxies in EAGLE is infalling for the first time. At the halo scale, the efficiency of recycling onto haloes differs by orders of magnitude from values assumed by semi-analytic galaxy formation models. Differences in the efficiency of wind recycling with other hydrodynamical simulations are currently difficult to assess, but are likely smaller. We are able to show that the fractional contribution of wind recycling to galaxy growth is smaller in EAGLE than in some other simulations. We find that cumulative first-time gas accretion rates at the virial radius are reduced relative to the expectation from dark matter accretion for haloes with mass, $M_{200} < 10^{12} \, \mathrm{M_\odot}$, indicating efficient preventative feedback on halo scales.
Realistic black hole collisions result in a rapidly rotating Kerr hole, but simulations to date have focused on nonrotating final holes. Using a new solution of the Einstein initial value equations we present here waveforms and radiation for an axisymmetric Kerr-hole-forming collision starting from small initial separation (the ``close limit'' approximation) of two identical rotating holes. Several new features are present in the results: (i) In the limit of small separation, the waveform is linear (not quadratic) in the separation. (ii) The waveforms show damped oscillations mixing quasinormal ringing of different multipoles.
We review the nucleon's twist-3 polarized structure functions from the viewpoint of gauge invariant, nonlocal light-cone operators in QCD. We discuss a systematic treatment of the polarized structure functions and the corresponding parton distribution functions. We emphasize unique features of higher twist distributions, and the role of the QCD equations of motion to derive their anomalous dimensions for Q^2-evolution.
A combined sample of 79 high and low redshift supernovae Ia (SNe) is used to set constraints on the degree of anisotropy in the Universe out to $z\simeq1$. First we derive the global most probable values of matter density $\Omega_M $, the cosmological constant $\Omega_\Lambda $, and the Hubble constant $H_0$, and find them to be consistent with the published results from the two data sets of Riess et al. 1998 (R98) and Perlmutter et al. 1999 (P99). We then examine the Hubble diagram (HD, i.e., the luminosity-redshift relation) in different directions on the sky by utilising spherical harmonic expansion. In particular, via the analysis of the dipole anisotropy, we divide the sky into the two hemispheres that yield the most discrepant of the three cosmological parameters, and the scatter $\chi^2_{\rm HD}$ in each case. The most discrepant values roughly move along the locus $-4\Omega_M +3 \Omega_{\Lambda} = 1$ (cf. P99), but by no more than $\Delta \approx 2.5$ along this line. For a perfect FRW universe, Monte Carlo realizations that mimic the current set of SNe yield values higher than the measured $\Delta$ in $\sim 1/5$ of the cases. We discuss implications for the validity of the Cosmological Principle, and possible calibration problems in the SNe data sets.
Alterations in the geometry and function of the heart define well-established causes of cardiovascular disease. However, current approaches to the diagnosis of cardiovascular diseases often rely on subjective human assessment as well as manual analysis of medical images. Both factors limit the sensitivity in quantifying complex structural and functional phenotypes. Deep learning approaches have recently achieved success for tasks such as classification or segmentation of medical images, but lack interpretability in the feature extraction and decision processes, limiting their value in clinical diagnosis. In this work, we propose a 3D convolutional generative model for automatic classification of images from patients with cardiac diseases associated with structural remodeling. The model leverages interpretable task-specific anatomic patterns learned from 3D segmentations. It further allows to visualise and quantify the learned pathology-specific remodeling patterns in the original input space of the images. This approach yields high accuracy in the categorization of healthy and hypertrophic cardiomyopathy subjects when tested on unseen MR images from our own multi-centre dataset (100%) as well on the ACDC MICCAI 2017 dataset (90%). We believe that the proposed deep learning approach is a promising step towards the development of interpretable classifiers for the medical imaging domain, which may help clinicians to improve diagnostic accuracy and enhance patient risk-stratification.
In this paper we show that there exist two different critical exponents for global small data solutions to the semilinear fractional diffusive equation with Caputo fractional derivative in time. The second critical exponent appears if the second data is assumed to be zero. This peculiarity is related to the fact that the order of the equation is fractional. To prove our result, we first derive Lr-Lq linear estimates for the solution to the inhomogeneous linear Cauchy problem and then we apply a contraction argument.
In this work we present a theoretical analysis of the convergence of the Wang-Landau algorithm [Phys. Rev. Lett. 86, 2050 (2001)] which was introduced years ago to calculate the density of states in statistical models. We study the dynamical behavior of the error in the calculation of the density of states.We conclude that the source of the saturation of the error is due to the decreasing variations of the refinement parameter. To overcome this limitation, we present an analytical treatment in which the refinement parameter is scaled down as a power law instead of exponentially. An extension of the analysis to the N-fold way variation of the method is also discussed.
Context. The structure of the wind from the cool giants in symbiotic binaries carries important information for understanding the wind mass transfer to their white dwarf companions and its fuelling. Aims. In this paper, we indicate a non-spherical distribution of the neutral wind zone around the red giant (RG) in the symbiotic binary star, EG And. Methods. We achieved this aim by analysing the periodic orbital variations of fluxes and radial velocities of individual components of the H$\alpha$ and [OIII]$\lambda$5007 lines observed on our high-cadence medium (R $\sim$ 11 000) and high-resolution (R $\sim$ 38 000) spectra. Results. The asymmetric shaping of the neutral wind zone at the near-orbital-plane region is indicated by: (i) the asymmetric course of the H$\alpha$ core emission fluxes along the orbit; (ii) the presence of their secondary maximum around the orbital phase $\varphi = 0.1$, which is possibly caused by the refraction effect; and (iii) the properties of the H$\alpha$ broad wing emission originating by Raman scattering on H$^0$ atoms. The wind is substantially compressed from polar directions to the orbital plane as constrained by the location of the [OIII]$\lambda$5007 line emission zones in the vicinity of the RG at/around its poles. The corresponding mass-loss rate from the polar regions of $\lesssim 10 ^{-8}$ Msun/yr is a factor of $\gtrsim 10$ lower than the average rate of $\approx 10^{-7}$Msun/yr derived from nebular emission of the ionised wind from the RG. Furthermore, it is two orders of magnitude lower than that measured in the near-orbital-plane region from Rayleigh scattering. Conclusions. The startling properties of the nebular [OIII]$\lambda$5007 line in EG And provides an independent indication of the wind focusing towards the orbital plane.
We report on the phenomenological results obtained through Dihadron Fragmentation Functions related processes. In 2015, an update on the fitting techniques for the Dihadron Fragmentation Functions has led to an improved extraction of the transversity PDF and, as a consequence, the nucleon tensor charge. We discuss the impact of the determination of the latter on search for physics Beyond the Standard Model, focusing on the error treatment. We also comment on the future of the extraction of the subleading-twist PDF $e(x)$ from JLab soon-to-be-released Beam Spin Asymmetry data.
We present recent results of quiescent X-ray observations of recurrent novae (RNe) and related objects. Several RNe are luminous hard X-ray sources in quiescence, consistent with accretion onto a near Chandrasekhar mass white dwarf. Detection of similar hard X-ray emissions in old novae and other cataclysmic variables may lead to identification of additional RN candidates. On the other hand, other RNe are found to be comparatively hard X-ray faint. We present several scenarios that may explain this dichotomy, which should be explored further.
In this paper we investigate an extremal problem on binary phylogenetic trees. Given two such trees $T_1$ and $T_2$, both with leaf-set ${1,2,...,n}$, we are interested in the size of the largest subset $S \subseteq {1,2,...,n}$ of leaves in a common subtree of $T_1$ and $T_2$. We show that any two binary phylogenetic trees have a common subtree on $\Omega(\sqrt{\log{n}})$ leaves, thus improving on the previously known bound of $\Omega(\log\log n)$ due to M. Steel and L. Szekely. To achieve this improved bound, we first consider two special cases of the problem: when one of the trees is balanced or a caterpillar, we show that the largest common subtree has $\Omega(\log n)$ leaves. We then handle the general case by proving and applying a Ramsey-type result: that every binary tree contains either a large balanced subtree or a large caterpillar. We also show that there are constants $c, \alpha > 0$ such that, when both trees are balanced, they have a common subtree on $c n^\alpha$ leaves. We conjecture that it is possible to take $\alpha = 1/2$ in the unrooted case, and both $c = 1$ and $\alpha = 1/2$ in the rooted case.
We consider the thresholding scheme and explore its connection to De Giorgi's ideas on gradient flows in metric spaces; here applied to mean curvature flow as the steepest descent of the interfacial area.   The basis of our analysis is the observation by Esedoglu and the second author that thresholding can be interpreted as a minimizing movements scheme for an energy that approximates the interfacial area.   De Giorgi's framework provides an optimal energy dissipation relation for the scheme in which we pass to the limit to derive a dissipation-based weak formulation of mean curvature flow.   Although applicable in the general setting of arbitrary networks, here we restrict ourselves to the case of a single interface, which allows for a compact, self-contained presentation.
Two XMM observations of the fast classical nova V2491Cyg were carried out on days 39.93 and 49.62 after discovery, during the supersoft source (SSS) phase, yielding simultaneous X-ray and UV light curves and high-resolution X-ray spectra. The first X-ray light curve is highly variable with periodic oscillations (37.2 min) after an extended dip of factor of three lasting ~3 hours. The cause of the dip is currently unexplained and could have the same origin as similar events in V4743Sgr and RSOph, as it occurred on the same time scale. The 37-min period is not present during the dip and also not in the second observation. The UV light curves are variable but contain no dips and no period. High-resolution X-ray spectra are presented for 4 intervals of different intensity. All spectra are atmospheric continua with absorption lines and absorption edges. Interstellar lines of OI and NI are seen at their rest wavelengths, and a large number of high-ionization absorption lines are found at blue shifts indicating an expansion velocity of 3000-3400 km/s, which does not change significantly during the epochs of observation. Comparisons with the slower nova V4743Sgr and the symbiotic recurrent nova RSOph are presented. The SSS spectrum of V4743Sgr is much softer with broader and more complex photospheric absorption lines. Meanwhile, the absorption lines in RSOph are as narrow as in V2491Cyg, but they are less blue shifted. A remarkable similarity in the continua of V2491Cyg and RSOph is found. The only differences are smaller line shifts and additional emission lines in RSOph that are related to a dense stellar wind from the evolved companion. Three unidentified absorption lines are present in the X-ray spectra of all three novae, with rest wavelengths 26.05AA, 29.45AA, and 30.0AA. No satisfactory spectral model is currently available for the soft X-ray spectra of novae in outburst.
We report on p-WSe2/n-MoS2 heterojunction diodes fabricated both on glass and SiO2/p+-Si substrates. The electrostatic performance and stability of our diode were successfully improved toward ideal current-voltage (I-V) behavior by adopting the fluoropolymer CYTOP encapsulation layer on top of our diode; reduction of reverse-bias leakage current and enhancement of forward-bias on current were achieved along with good aging stability in air ambient. Such performance improvement is attributed to the intrinsic properties of CYTOP materials with C-F bonds whose strong dipole moment causes hole accumulation, while the strong hydrophobicity of CYTOP would prevent ambient molecule adsorption on 2D semiconductor surface. Moreover, fabricated on glass, our p-n diode displayed good dynamic rectification at over 100 Hz, without displacement current-induced signal overshoot/undershoot which was shown in the other diode on SiO2/p+-Si. Little I-V hysteresis in our diode is another benefit of glass substrate. We conclude that our CYTOP-encapsulated WSe2/MoS2 p-n diode on glass is a high performance and ambient stable 2D nanodevice toward future advanced electronics.
We propose that the pseudogap state observed in the transition metal oxides can be explained by a three-dimensional flux state, which exhibits spontaneously generated currents in its ground state due to electron-electron correlations. We compare the energy of the flux state to other classes of mean field states, and find that it is stabilized over a wide range of $t$ and $\delta$. The signature of the state will be peaks in the neutron diffraction spectra, the location and intensity of which are presented. The dependence of the pseudogap in the optical conductivity is calculated based on the parameters in the model.
A robust solution for semi-dense stereo matching is presented. It utilizes two CNN models for computing stereo matching cost and performing confidence-based filtering, respectively. Compared to existing CNNs-based matching cost generation approaches, our method feeds additional global information into the network so that the learned model can better handle challenging cases, such as lighting changes and lack of textures. Through utilizing non-parametric transforms, our method is also more self-reliant than most existing semi-dense stereo approaches, which rely highly on the adjustment of parameters. The experimental results based on Middlebury Stereo dataset demonstrate that the proposed approach outperforms the state-of-the-art semi-dense stereo approaches.
We review the application of torsion in field theory. First we show how the notion of torsion emerges in differential geometry. In the context of a Cartan circuit, torsion is related to translations similar as curvature to rotations. Cartan's investigations started by analyzing Einsteins general relativity theory and by taking recourse to the theory of Cosserat continua. In these continua, the points of which carry independent translational and rotational degrees of freedom, there occur, besides ordinary (force) stresses, additionally spin moment stresses. In a 3-dimensional continuized crystal with dislocation lines, a linear connection can be introduced that takes the crystal lattice structure as a basis for parallelism. Such a continuum has similar properties as a Cosserat continuum, and the dislocation density is equal to the torsion of this connection. Subsequently, these ideas are applied to 4-dimensional spacetime. A translational gauge theory of gravity is displayed (in a Weitzenboeck or teleparallel spacetime) as well as the viable Einstein-Cartan theory (in a Riemann-Cartan spacetime). In both theories, the notion of torsion is contained in an essential way. Cartan's spiral staircase is described as a 3-dimensional Euclidean model for a space with torsion, and eventually some controversial points are discussed regarding the meaning of torsion.
We present FLAMES/GIRAFFE integral field spectroscopy of 30 galaxies in the massive cluster Abell 1689 at z = 0.183. Conducting an analysis similar to that of ATLAS3D, we extend the baseline of the kinematic morphology-density relation by an order of magnitude in projected density and show that it is possible to use existing instruments to identify slow and fast rotators beyond the local Universe. We find 4.5 +- 1.0 slow rotators with a distribution in magnitude similar to those in the Virgo cluster. The overall slow rotator fraction of our Abell 1689 sample is 0.15 +- 0.03, the same as in Virgo using our selection criteria. This suggests that the fraction of slow rotators in a cluster is not strongly dependent on its density. However, within Abell 1689, we find that the fraction of slow rotators increases towards the centre, as was also found in the Virgo cluster.
This paper proposes a two-stream convolution network to extract spatial and temporal cues for video based person Re-Identification (ReID). A temporal stream in this network is constructed by inserting several Multi-scale 3D (M3D) convolution layers into a 2D CNN network. The resulting M3D convolution network introduces a fraction of parameters into the 2D CNN, but gains the ability of multi-scale temporal feature learning. With this compact architecture, M3D convolution network is also more efficient and easier to optimize than existing 3D convolution networks. The temporal stream further involves Residual Attention Layers (RAL) to refine the temporal features. By jointly learning spatial-temporal attention masks in a residual manner, RAL identifies the discriminative spatial regions and temporal cues. The other stream in our network is implemented with a 2D CNN for spatial feature extraction. The spatial and temporal features from two streams are finally fused for the video based person ReID. Evaluations on three widely used benchmarks datasets, i.e., MARS, PRID2011, and iLIDS-VID demonstrate the substantial advantages of our method over existing 3D convolution networks and state-of-art methods.
Extreme conditions in natural flows are examined, starting with a turbulent big bang. A hydro-gravitational-dynamics cosmology model is adopted. Planck-Kerr turbulence instability causes Planck-particle turbulent combustion. Inertial-vortex forces induce a non-turbulent kinetic energy cascade to Planck-Kolmogorov scales where vorticity is produced, overcoming 10^113 Pa Planck-Fortov pressures. The spinning, expanding fireball has a slight deficit of Planck antiparticles. Space and mass-energy powered by gluon viscous stresses expand exponentially at speeds >10^25 c. Turbulent temperature and spin fluctuations fossilize at scales larger than ct, where c is light speed and t is time. Because "dark-energy" antigravity forces vanish when inflation ceases, and because turbulence produces entropy, the universe is closed and will collapse and rebound. Density and spin fossils of big bang turbulent mixing trigger structure formation in the plasma epoch. Fragmenting protosuperclustervoids and protoclustervoids produce weak turbulence until the plasma-gas transition give chains of protogalaxies with the morphology of turbulence. Chain galaxy clusters observed at large redshifts ~8.6 support this interpretation. Protogalaxies fragment into clumps, each with a trillion Earth-mass H-He gas planets. These make stars, supernovae, the first chemicals, the first oceans and the first life soon after the cosmological event.
We present an improved determination of the total mass distribution of three CLASH/HFF massive clusters, MACS J1206.2-0847 (z=0.44), MACS J0416.1-2403 (z=0.40), Abell S1063 (z=0.35). We specifically reconstruct the sub-halo mass component with robust stellar kinematics information of cluster galaxies, in combination with precise strong lensing models based on large samples of spectroscopically identified multiple images. We use VLT/MUSE integral-field spectroscopy in the cluster cores to measure the stellar velocity dispersion, $\sigma$, of 40-60 member galaxies per cluster, covering 4-5 magnitudes to $m_{F160W}\simeq 21.5$. We verify the robustness and quantify the accuracy of the velocity dispersion measurements with extensive spectral simulations. With these data, we determine the normalization and slope of the galaxy $L\mbox{-}\sigma$ Faber-Jackson relation in each cluster and use these parameters as a prior for the scaling relations of the sub-halo population in the mass distribution modeling. When compared to our previous lens models, the inclusion of member galaxies' kinematics provides a similar precision in reproducing the positions of the multiple images. However, the inherent degeneracy between the central effective velocity dispersion, $\sigma_0$, and truncation radius, $r_{cut}$, of sub-halos is strongly reduced, thus significantly alleviating possible systematics in the measurements of sub-halo masses. The three independent determinations of the $\sigma_0\mbox{-}r_{cut}$ scaling relation in each cluster are found to be fully consistent, enabling a statistical determination of sub-halo sizes as a function of $\sigma_0$, or halo masses. We derive galaxy central velocity dispersion functions of the three clusters and found them in agreement with each other. Sub-halo mass functions determined with this method can be compared with those obtained from cosmological simulations.
The dipole response function of nuclear matter at zero and finite temperatures is investigated by employing the linearized version of the extended TDHF theory with a non-Markovian binary collision term. Calculations are carried out for nuclear dipole vibrations by employing the Steinwedel-Jensen model and compared with experimental results for $^{120}Sn$ and $^{208}Pb$.