ShantanuT01/DACTYL-Pretraining huggingface dataset:
Cystic fibrosis is a genetic disease which may appear in early life with structural abnormalities in lung tissues. We propose to detect these abnormalities using a texture classification approach. Our method is a cascade of two convolutional neural networks. The first network detects the presence of abnormal tissues. The second network identifies the type of the structural abnormalities: bronchiectasis, atelectasis or mucus plugging.We also propose a network computing pixel-wise heatmaps of abnormality presence learning only from the patch-wise annotations. Our database consists of CT scans of 194 subjects. We use 154 subjects to train our algorithms and the 40 remaining ones as a test set. We compare our method with random forest and a single neural network approach. The first network reaches an accuracy of 0,94 for disease detection, 0,18 higher than the random forest classifier and 0,37 higher than the single neural network. Our cascade approach yields a final class-averaged F1-score of 0,33, outperforming the baseline method and the single network by 0,10 and 0,12.
Recent cosmic microwave background data in temperature and polarization have reached high precision in estimating all the parameters that describe the current so-called standard cosmological model. Recent results about the integrated Sachs-Wolfe effect from cosmic microwave background anisotropies, galaxy surveys, and their cross-correlations are presented. Looking at fine signatures in the cosmic microwave background, such as the lack of power at low multipoles, the primordial power spectrum and the bounds on non-Gaussianities, complemented by galaxy surveys, we discuss inflationary physics and the generation of primordial perturbations in the early Universe. Three important topics in particle physics, the bounds on neutrinos masses and parameters, on thermal axion mass and on the neutron lifetime derived from cosmological data are reviewed, with attention to the comparison with laboratory experiment results. Recent results from cosmic polarization rotation analyses aimed at testing the Einstein equivalence principle are presented. Finally, we discuss the perspectives of next radio facilities for the improvement of the analysis of future cosmic microwave background spectral distortion experiments.
We extend to infinite graphs the matroidal characterization of finite graph duality, that two graphs are dual iff they have complementary spanning trees in some common edge set. The naive infinite analogue of this fails.   The key in an infinite setting is that dual trees must share between them not only the edges of their host graphs but also their ends: the statement that a set of edges is acyclic and connects all the vertices in one of the graphs iff the remaining edges do the same in its dual will hold only once each of the two graphs' common ends has been assigned to one graph but not the other, and 'cycle' and 'connected' are interpreted topologically in the space containing the respective edges and precisely the ends thus assigned.   This property characterizes graph duality: if, conversely, the spanning trees of two infinite graphs are complementary in this end-sharing way, the graphs form a dual pair.
Segmentation of blood vessels in retinal images provides early diagnosis of diseases like glaucoma, diabetic retinopathy and macular degeneration. Among these diseases occurrence of Glaucoma is most frequent and has serious ocular consequences that can even lead to blindness, if it is not detected early. The clinical criteria for the diagnosis of glaucoma include intraocular pressure measurement, optic nerve head evaluation, retinal nerve fiber layer and visual field defects. This form of blood vessel segmentation helps in early detection for ophthalmic diseases, and potentially reduces the risk of blindness. The low-contrast images at the retina owing to narrow blood vessels of the retina are difficult to extract. These low contrast images are, however useful in revealing certain systemic diseases. Motivated by the goals of improving detection of such vessels, this present work proposes an algorithm for segmentation of blood vessels and compares the results between expert ophthalmologist hand-drawn ground-truths and segmented image(i.e. the output of the present work).Sensitivity, specificity, positive predictive value (PPV), positive likelihood ratio (PLR) and accuracy are used to evaluate overall performance.It is found that this work segments blood vessels successfully with sensitivity, specificity, PPV, PLR and accuracy of 99.62%, 54.66%, 95.08%, 219.72 and 95.03%, respectively.
After analyzing the implication of investigations on the C, P and T transformations since 1956, we propose that there is a basic symmetry in particle physics. The combined space-time inversion is equivalent to particle-antiparticle transformation, denoted by ${\cal PT=C}$. It is shown that the relativistic quantum mechanics and quantum field theory do contain this invariance explicitly or implicitly. In particular, (a) the appearance of negative energy or negative probability density in single particle theory -- corresponding to the fact of existence of antiparticle, (b) spin- statistics connection, (c) CPT theorem, (d) the Feynman propagator are linked together via this symmetry. Furthermore, we try to derive the main results of special relativity, especially, (e) the mass-energy relation, (f) the Lorentz transformation by this one ``relativistic'' postulate and some ``nonrelativistic'' knowledge.
A fourientation of a graph $G$ is a choice for each edge of the graph whether to orient that edge in either direction, leave it unoriented, or biorient it. We may naturally view fourientations as a mixture of subgraphs and graph orientations where unoriented and bioriented edges play the role of absent and present subgraph edges, respectively. Building on work of Backman and Hopkins (2015), we show that given a linear order and a reference orientation of the edge set, one can define activities for fourientations of $G$ which allow for a new 12 variable expansion of the Tutte polynomial $T_G$. Our formula specializes to both the Las Vergnas (1984) orientation activites expansion of the Tutte polynomial and the generalized activities expansion of Gordon and Traldi (1990).
The class of transition metal compounds shows an enormous richness of physical properties, such as metal-insulator transitions, colossal magneto-resistance, super-conductivity, magneto-optics and spin-depend transport. It now becomes more and more clear that in order to describe transition metal compounds the charge, orbital, spin and lattice degrees of freedom should all be taken into account. With the recognition that the local orbital occupation plays an important role in many of the transition metal compounds there is a need for experimental techniques that can measure the orbital occupation. This technique is soft x-ray absorption spectroscopy. Within this PhD. Thesis we will illustrate the usefulness of this technique by some examples: 1) Magnetic versus crystal-field linear dichroism in NiO thin films. 2) The importance of spin-orbit coupling in CoO bulk and CoO thin films. 3) Aligning spins in anti ferromagneticfilms using antiferromagnets. 4) The spin-state puzzle in the cobaltates. 5) Determination of the orbital momentum and crystal-field splitting in LaTiO3. 6) Orbital-assisted metal-insulator transition in VO2.
For almost one year the Large Area Telescope on board the Fermi observatory has been surveying high-energy phenomena in our Universe. We will present an overview of the status of the mission and of some results from the first year of observations, focusing on the topics of particular interest for the high-energy Physics community: detection of high-energy gamma-ray bursts, the discovery of new populations of gamma-ray sources, non-confirmation of the excess of diffuse GeV gamma-ray emission seen by EGRET and, in greater detail, the recent measurement of the cosmic-ray electron spectrum from 20 GeV to 1 TeV.
We present spectroscopic X-ray data of two candidate ultra-compact X-ray binaries: 4U~0614+091 and 4U~1543$-$624. We confirm the presence of a broad O VIII Ly$\alpha$ reflection line (at $\approx18\ \AA$) using {\it XMM-Newton} and {\it Chandra} observations obtained in 2012 and 2013. The donor star in these sources is carbon-oxygen or oxygen-neon-magnesium white dwarf. Hence, the accretion disc is enriched with oxygen which makes the O VIII Ly$\alpha$ line particularly strong. We also confirm the presence of a strong absorption edge at $\approx14$ \AA\ so far interpreted in the literature as due to absorption by neutral neon in the circumstellar and interstellar medium. However, the abundance required to obtain a good fit to this edge is $\approx3-4$ times solar, posing a problem for this interpretation. Furthermore, modeling the X-ray reflection off a carbon and oxygen enriched, hydrogen and helium poor disc with models assuming solar composition likely biases several of the best-fit parameters. In order to describe the X-ray reflection spectra self-consistently we modify the currently available {\sc xillver} reflection model. We present initial grids that can be used to model X-ray reflection spectra in UCXBs with carbon-oxygen-rich accretion disc. We find that the new reflection model provides a better overall description of the reflection spectra of 4U~0614+091 and 4U~1543$-$624 than the reflection models that assume solar abundances. Besides a strong O VIII Ly$\alpha$ line the new reflection model also shows a strong O VIII K-edge (at $14.23$ \AA). We find that the absorption edge at $\approx 14$ \AA\ present in the data can be described by a O VIII K-edge formed due to reflection in the accretion disc and a Ne I K-edge originating mostly in the interstellar medium, mitigating the problem of the apparent very high neon abundance.
The discovery of the first diffuse interstellar bands (DIBs) dates back to the pioneering years of stellar spectroscopy. Today, we know about 300 absorption structures of this kind. There exists a great variety of the profiles and intensities of DIBs, so they can not be readily described, classified or characterized. To the present day no reliable identification of the DIBs' carriers has been found. Many carriers of DIBs have been proposed over the years. They ranged from dust grains to free molecules of different kinds, and to more exotic specimens, like hydrogen negative ion. Unfortunately, none of them is responsible for observed DIBs. Furthermore, it was shown that a single carrier cannot be responsible for all known DIBs. It is hard to estimate how many carriers can participate in producing these bands. The problem is further complicated by the fact that to this day it is still impossible to find any laboratory spectrum of any substance which would match the astrophysical spectra. Here, a historical outline concerning DIBs is followed by a brief description of their whole population. Then, a special attention is focused on the procedures trying to extract spectroscopic families within the set of all known DIBs.
We transform, by means of a fiberwise duality, the partition function of QCD on a product of two two-tori, into a four-dimensional sigma-model, whose target space is the cotangent space of unitary connections on the fiber torus fiberwise.
We study the natural extension of spacetime across Schwarzschild's central singularity and the behavior of the geodesics crossing it. Locality implies that this extension is independent from the future fate of black holes. We argue that this extension is the natural $\hbar\!\to\!0$ limit of the effective quantum geometry inside a black hole, and show that the central region contains causal diamonds with area satisfying Bousso's bound for an entropy that can be as large as Hawking's radiation entropy. This result sheds light on the possibility that Hawking radiation is purified by information crossing the internal singularity.
In the "secretary problem", well-known in the theory of optimal stopping, an employer is about to interview a maximum of N secretaries about which she has no prior information. Chow et al. proved that with an optimal strategy the expected rank of the chosen secretary tends to approximately 3.87.   We study a two-sided game-theoretic version of this optimal stopping problem, where men search for a woman to marry at the same time as women search for a man to marry. We find that in the unique subgame perfect equilibrium, the expected rank grows as the square root of N and that, surprisingly, the leading coefficient is exactly 1. We also discuss some possible variations.
For a given spatial distribution of the lenses and distribution of the transverse velocity of the lens relative to the line-of-sight, a probability distribution for the lens mass for a single observed event is derived. In addition, similar probability distributions are derived for the Einstein radius and the separation of the lens objects and their rotation period for a binary lens. These probability distributions are distinct from the distributions for the lens population, as investigated e.g. by the mass moment method of De Rujula, Jetzer, and Masso (1991). However, it is shown that the expectation value for the mass from the probability distribution coincides with the value from the mass moment method applied to a single observed event. The special cases of a Maxwellian velocity distribution and of a constant velocity are discussed in detail. For a rudimentary model of the Galactic halo, the probability distributions are shown and the relations between the expectation values of the physical quantities and the event timescale are given. For this model, it is shown that within a 95.4%-interval around the expectation value, the mass varies by a factor of 800.
Urea, NH2C(O)NH2, is a molecule of great importance in organic chemistry and biology. Two searches for urea in the interstellar medium were reported in the past, but neither were conclusive. We want to take advantage of the increased sensitivity and angular resolution provided by ALMA to search for urea toward the hot cores embedded in the high-mass star forming region Sgr B2(N). We use the new spectral line survey ReMoCA performed toward Sgr B2(N) with ALMA in its observing cycle 4. The spectra are analyzed under the LTE approximation. We construct a full synthetic spectrum that includes all the molecules identified so far. We use new spectroscopic predictions for urea in its vibrational ground state and first vibrationally excited state to search for this complex organic molecule in the ReMoCA data set. We employ the gas-grain chemical kinetics model MAGICKAL to interpret the astronomical observations. We report the secure detection of urea toward the hot core Sgr B2(N1) at a position called N1S slightly offset from the continuum peak, which avoids obscuration by the dust.. We derive a column density of 2.7x10^16 cm-2 for urea, two orders of magnitude lower than formamide, and one order of magnitude below methyl isocyanate, acetamide, and N-methylformamide. The latter molecule is reliably identified toward N1S with 60 clearly detected lines, confirming an earlier claim of its tentative interstellar detection. We report the first interstellar detections of NH2CH18O and 15NH2CHO. We also report the nondetection of urea toward the secondary hot core Sgr B2(N2) with an abundance relative to the other four species at least one order of magnitude lower than toward the main hot core. Our chemical model roughly reproduces the relative abundances of formamide, methyl isocyanate, acetamide, and N-methylformamide, but it overproduces urea by at least one order of magnitude.
We prove that every abelian permutation group, but known exceptions, is the symmetry group of a boolean function. This solves the problem posed in the book by Clote and Kranakis. In fact, our result is proved for a larger class of groups, namely, for all groups contained in direct sums of regular groups.
Reheating phase of inflationary Universe can be modeled by parameters $T_{\text{reh}}$, $\bar{w}_{\text{reh}}$ and $N_{\text{reh}}$, which can be constrained by the scalar spectral amplitude $A_{s}$ and the scalar spectral index $n_{s}$. On the other hand the low multipole anomalies in the CMB can be modeled by suitable features in the inflaton potential. We show that the parameters of these features in the inflaton potential provide additional constraints on the reheating parameters. For several single field models we find that the reheating parameters are substantially more constrained by the requirement of compatibility with the proposed explanation for low multipole anomalies.
Given a subset $S$ of the non-identity elements of the dihedral group of order $2m$, is it possible to order the elements of $S$ so that the partial products are distinct? This is equivalent to the sequenceability of the group when $|S| = 2m-1$ and so it is known that the answer is yes in this case if and only if $m>4$. We show that the answer is yes when $|S| \leq 9$ and $m$ is an odd prime other than 3, when $|S| = 2m-2$ and $m$ is even or prime, and when $|S| = 2m-2$ for many instances of the problem when $m$ is odd and composite. We also consider the problem in the more general setting of arbitrary non-abelian groups and discuss connections between this work and the concept of strong sequenceability.
In this paper the phenomenon of dynamic heterogeneity in supercooled liquid systems is considered in terms of the recently proposed gauge theory of glass transition. The physical interpretation of the dynamic scaling is considered. It is shown that the development of the dynamic heterogeneity occurs due to the growth areas in which molecular motion is correlated due to the elastic interaction described by the gauge field. We obtains the analytical expressions for the dependence of the number of dynamically correlated atoms as the function on the system relaxation time, and the time dependence of the dynamic susceptibility near the glass transition. It is shown that the relaxation consists two processes: $\alpha $-relaxation process corresponding to the joint motion of the domains disordered with each other, and $\beta$-relaxation process corresponding to the motion inside these domains.
An extension of the Zee model involving a light right handed neutrino, nu_R is considered. We update constraints on couplings between the bilepton scalar, the active neutrinos, nu_R and the charged leptons. We find that the most stringent constraint currently comes from measurements limiting the width of the decay mu -> e gamma. These are used to predict the upper bound on violation of lepton universality in leptonic W boson decays and rare Z decays, such as Z -> e mu.
Since T-duality has been proved only perturbatively and most of the heterotic states map into solitonic, non-perturbative, type II states, the 6-dimensional string-string duality between the heterotic string and the type II string is not sufficient to prove the S-duality of the former, in terms of the known T-duality of the latter. We nevertheless show in detail that perturbative T-duality, together with the heterotic-type II duality, does imply the existence of heterotic H-monopoles, with the correct multiplicity and multiplet structure. This construction is valid at a generic point in the moduli space of heterotic toroidal compactifications.
We have studied the growth kinetics of isolated precipitates growing from a supersaturated matrix in 3-dimensions (3-D) using phase field models; we assume isotropic interfacial energy consider both constant and variable diffusivity. We report and compare our numerical growth rates with the classic analytical solutions of Zener and Frank (ZF). The numerical results deviate from the analytical ones. These deviations can be understood in terms of the generalised Gibbs-Thomson effect. Specifically, due to the higher capillary contribution in 3-D (curvature is twice for a sphere compared to a circle), the precipitate growth kinetics deviates more from ZF in 3-D as compared to 2-D. In addition, the kinetic parameter associated with the normal velocity of the precipitate-matrix interface also modifies the deviation of the precipitate composition from its equilibrium value and hence its growth kinetics. In phase field models (such as the one used by us) which use a combination of Allen-Cahn and Cahn-Hilliard type equations, we show how to choose the kinetic parameters (namely, mobility and relaxation parameter) so that the kinetic coefficient (in the generalised Gibbs-Thomson equation) is made effectively zero. We also show that the kinetic parameter the precipitate-matrix interface might play a crucial role in making the precipitate undergo morphological instabilities as it grows (leading to "sea-weed"-like structures).
The F-GAMMA program is a coordinated effort to investigate the physics of Active Galactic Nuclei (AGNs) via multi-frequency monitoring of {\em Fermi} blazars. The current study is concerned with the broad-band radio spectra composed of measurement at ten frequencies between 2.64 and 142 GHz. It is shown that any of the 78 sources studied can be classified in terms of their variability characteristics in merely 5 types of variability. The first four types are dominated by spectral evolution and can be reproduced by a simple two-component system made of the quiescent spectrum of a large scale jet populated with a flaring event evolving according to Marscher & Gear (1985). The last type is characterized by an achromatic change of the broad-band spectrum which must be attributed to a completely different mechanism. Here are presented, the classification, the assumed physical system and the results of simulations that have been conducted.
In general, when a black hole evaporates, there arises a net energy flow from black hole into its outside environment due to Hawking radiation and energy accretion onto black hole. The existence of energy flow means that the thermodynamic state of the whole system, which consists of a black hole and its environment, is in a nonequilibrium state. To know the detail of evaporation process, the nonequilibrium effects of energy flow should be taken into account. The nonequilibrium nature of black hole evaporation is a challenging topic including issues of not only black hole physics but also nonequilibrium physics. Using the nonequilibrium thermodynamics which has been formulated recently, this report shows: (1) the self-gravitational effect of black hole which appears as its negative heat capacity guarantees the validity of generalized 2nd law without entropy production inside the outside environment, (2) the nonequilibrium effect of energy flow tends to shorten the evaporation time (life time) of black hole, and consequently specific nonequilibrium phenomena are suggested. Finally a future direction of this study is commented.
We study the relation between mesogranular flows, convectively driven sinks and magnetic fields using high spatial resolution spectropolarimetric data acquired with the Imaging Magnetograph eXperiment on board Sunrise. We obtain the horizontal velocity flow fields of two quiet-Sun regions (31.2 $\times$ 31.2 Mm$^{2}$) via local correlation tracking. Mesogranular lanes and the central position of sinks are identified using Lagrange tracers. We find $6.7\times10^{-2}$ sinks per Mm$^{2}$ in the two observed regions. The sinks are located at the mesogranular vertices and turn out to be associated with (1) horizontal velocity flows converging to a central point and (2) long-lived downdrafts. The spatial distribution of magnetic fields in the quiet Sun is also examined. The strongest magnetic fields are preferentially located at sinks. We find that 40 \% of the pixels with longitudinal component of the magnetic field stronger than 500 G are located in the close neighborhood of sinks. In contrast, the small-scale magnetic loops detected by Mart\'{i}nez Gonz\'{a}lez et al. in the same two observed areas do not show any preferential distribution at mesogranular scales. The study of individual examples reveals that sinks can play an important role in the evolution of quiet-Sun magnetic features.