Miracle-dz/UniFAR-FTUs huggingface dataset:
THE CORONAL SOURCE OF EXTREME-ULTRAVIOLET LINE PROFILE ASYMMETRIES IN SOLAR ACTIVE REGION OUTFLOWS

High-resolution spectra from the Hinode EUV Imaging Spectrometer have revealed that coronal spectral line profiles are sometimes asymmetric, with a faint enhancement in the blue wing on the order of 100 km s−1. These asymmetries could be important since they may be subtle yet diagnostically useful signatures of coronal heating or solar wind acceleration processes. It has also been suggested that they are signatures of chromospheric jets supplying mass and energy to the corona. Until now, however, there have been no studies of the physical properties of the plasma producing the asymmetries. Here we identify regions of asymmetric profiles in the outflows of AR 10978 using an asymmetric Gaussian function and extract the intensities of the faint component using multiple Gaussian fits. We then derive the temperature structure and chemical composition of the plasma producing the asymmetries. We find that the asymmetries are dependent on temperature, and are clearer and stronger in coronal lines. The temperature distribution peaks around 1.4–1.8 MK with an emission measure at least an order of magnitude larger than that at 0.6 MK. The first ionization potential bias is found to be 3–5, implying that the high-speed component of the outflows may also contribute to the slow-speed wind. Observations and models indicate that it takes time for plasma to evolve to a coronal composition, suggesting that the material is trapped on closed loops before escaping, perhaps by interchange reconnection. The results, therefore, identify the plasma producing the asymmetries as having a coronal origin.
EECS 182/282A Lecture 17: Transformer Models

We have spent a lot of time understanding the idea of self-supervision where we only have access to unlabeled data (just like in unsupervised learning) and use data themselves to generate labels. One example that proved such learning scheme useful is doing PCA-style dimensionality reduction “purification” in an autoencoder style with self-supervision. Apart from PCA, k-means style clustering where we assign unlabeled data to groups is another kind of traditional unsupervised learning. In the first part of the lecture, we attempt to make k-means clustering compatible with gradient descent. Then, we will connect to the idea of attention and introduce transformer models.
Topological Enrichment of Luttinger's Theorem

We establish a generalization of Luttinger's theorem that applies to fractionalized Fermi liquids, i.e. Fermi liquids coexisting with symmetry enriched topological order. We find that, in the linear relation between the Fermi volume and the density of fermions, the contribution of the density is changed by the filling fraction associated with the topologically ordered sector, which is determined by how the symmetries fractionalize. Conversely, this places constraints on the allowed symmetry enriched topological orders that can manifest in a fractionalized Fermi liquid with a given Fermi volume and density of fermions.
Elementary abelian regular subgroups as hidden sums for cryptographic trapdoors

We study special subgroups of the affine general linear group acting on a vector space. To be more precise, we study elementary abelian regular sub- groups. It turns out that these have a strong cryptographic significance, since they can be exploited to insert or detect algebraic trapdoors in block ciphers. When used in this context, they take the name of hidden sums. Our results include a convenient representation of their elements, a classification of their conjugacy classes and several combinatorial counting formulas. We also show how to use hidden sums to attack a block cipher and we hint at ongoing research, where the hidden sums are studied to obtain more sophisticated algebraic attacks.
Effect of Acidulant on Chicken Pickle Incorporated with Poultry By-products

The present study was aimed to develop an acceptable quality chicken pickle with incorporation of poultry by products viz. Heart and gizzard (1:1). Different levels of heart and gizzard (5, 10 and 15%) were incorporated in chicken pickle formulations. It was observed that incorporation of 10% heart and gizzard exhibited higher sensory scores and physico-chemical properties which were comparable to the control. Chicken pickle prepared by using selected level of heart and gizzard (10%) was further incorporated with different acidulants viz. citric acid, acetic acid and lactic acid for sensory and physico-chemical properties and evaluated at ambient temperature on every 15 th day interval for 90 days. During storage chicken pickle incorporated with acetic acid maintained sensory and physico-chemical attributes for longer time as compared to the products incorporated with citric acid and lactic acid. During storage of chicken pickle the sensory scores for all the attributes declined significantly with the progress of storage period. Similarly, pH, TBA values and microbial count increased considerably at the later part of storage but were within spoilage limit.
Building ASR systems using Resource-Rich and Resource-Poor languages

Here the role of H(·) is to properly estimate/predict this function. These ASR systems have multiple applications in various domains like health care, automobile, IoT devices, etc. The performance of the ASR system gets affected if there are too many acoustic variations [1] in the speech signals. The main cause of these variations might be due to (1) Distortion in the microphone, electrical noise, directional characteristics, (2) Overlapping speech, background noise, reverberations, and (3) different speaking styles like stress/emotion, high or low speaking rate, stuttering, Lombard effects. In a practical scenario, building an ASR system is a challenging task as it has to address the following issues, (1) Noise [2, 3, 4], (2) Accent [5, 6, 7], (3) Single-channel, Multi-Channel (4) Low-resource [8, 9, 10] (5) Multilingual [11, 12] (6) Code-switching. I would be addressing Low-resource and multilingual problems for my doctoral research. So there arises a question what does a “low-resource” [13] mean? In general, a language is considered to be low-resource if they fall under any of the following:(1) limited web presence, (2) lack of linguistic expertise, digital resource (audio or text corpora). In order to build an ASR model to achieve human parity we need to have a tons of labeled speech corpus for training. Recently [14, 15], has shown that the English ASR system has reached human parity for a generic domain. And the amount of labeled data available for the English ASR task is 30,000 hours [16, 17]. But this is not in the case of Indic languages, and we can hardly find in the magnitude of hundreds. So in my work, I would be addressing how to procure the data from the crowd, the internet (as there is a lot of freely available) and curated it into the ASR format. In my case, I have collected around 2000 hours of Telugu Speech corpus in crowdsource manner. So the next question is “what is multilingual”? Let’s consider a country like India, where numerous languages are being spoken across different geographical locations. So building a monolingual ASR system for all the languages is complex, and handling it involves too much computation. And it also requires a good amount of training data to build. To mitigate this issue, I will be building a Joint Acoustic Model (JAM) across all the languages. For a JAM, we will be pooling the data from all the languages and build a single acoustic model so that the attributes are shared across the languages. It is observed that such kind of approach is being benefited for building low-resource multilingual ASR systems.
Probing a scattering resonance in Rydberg molecules with a Bose-Einstein condensate

We present spectroscopy of a single Rydberg atom excited within a Bose-Einstein condensate. We not only observe the density shift as discovered by Amaldi and Segrè in 1934 [1], but a line shape which changes with the principal quantum number n. The line broadening depends precisely on the interaction potential energy curves of the Rydberg electron with the neutral atom perturbers. In particular, we show the relevance of the triplet p-wave shape resonance in the e--Rb(5S) scattering, which significantly modifies the interaction potential. With a peak density of 5.5×1014 cm-3, and therefore an inter-particle spacing of 1300 a0 within a Bose-Einstein condensate, the potential energy curves can be probed at these Rydberg ion neutral atom separations. We present a simple microscopic model for the spectroscopic line shape by treating the atoms overlapped with the Rydberg orbit as zero-velocity, uncorrelated, point-like particles, with binding energies associated with their ion-neutral separation, and good agreement is found.
Quantum interference as a resource for quantum speedup

Quantum states can in a sense be thought of as generalizations of classical probability distributions, but are more powerful than probability distributions when used for computation or communication. Quantum speedup therefore requires some feature of quantum states that classical probability distributions lack. One such feature is interference. We quantify interference and show that there can be no quantum speedup due to a small number of operations incapable of generating large amounts of interference (although large numbers of such operations can in fact lead to quantum speedup). Low-interference operations include sparse unitaries, Grover reflections, short time/low energy Hamiltonian evolutions, and the Haar wavelet transform. Circuits built from such operations can be classically simulated via a Monte Carlo technique making use of a convex combination of two Markov chains. Applications to query complexity, communication complexity, and the Wigner representation are discussed.
Numerical modelling of Auriga’s Wheel – a new ring galaxy

We model the formation of Auriga’s Wheel – a recently discovered collisional ring galaxy. Auriga’s Wheel has a number of interesting features including a bridge of stars linking the neighbouring elliptical to the ring galaxy, and evidence for components of expansion and rotation within the ring. Using N-body/smoothed particle hydrodynamics modelling, we study collisions between an elliptical galaxy and a late-type disc galaxy. A near direct collision, with a mildly inclined disc, is found to reasonably reproduce the general system morphology ∼50 Myr following the collision. The collision must have a relatively low velocity (initially ∼150 km s−1) in order to form the observed bridge, and simultaneously match the galaxies separation. Our best-match model suggests the total disc galaxy is ∼5 times more massive than the elliptical. We find that the velocity of expansion of the ring is sensitive to the mass of the elliptical, while insensitive to the encounter velocity. We evolve our simulation beyond the current epoch to study the future destiny of the galaxy pair. In our model, the nucleus moves further away from the plane of the ring in the direction of the stellar bridge. The nucleus eventually merges with the elliptical galaxy ∼100 Myr after the present time. The ring continues to expand for ∼200 Myr before collapsing back. The low initial relative velocity of the two galaxies will eventually result in a complete merger.
A novel and sensitive method for measuring very weak magnetic fields of DA white dwarfs. A search for a magnetic field at the 250 G level in 40 Eridani B

Searches for magnetic fields in white dwarfs have clarified both the frequency of occurrence and the global structure of the fields found down to field strengths of the order of 500 kG. Below this level, the situation is still very unclear. We are studying the weakest fields found in white dwarfs to determine the frequency of such fields and their structure. We describe a very sensitive new method of measuring such fields in DA (H-rich) white dwarfs, and search for a field in the brightest such star, 40 Eri B. Our new method makes use of the strongly enhanced polarisation signal in the sharp core of Halpha. We find that with one-hour integrations with the high-resolution spectropolarimeter ESPaDOnS on the 3.6-m CFHT, we can reach a standard error fo the longitudinal field of about 85 G, the smallest error ever achieved for any white dwarf. Nevertheless, we do not detect a magnetic field in this star. Observations with ISIS at the WHT, and the Main Stellar Spectrograph at the SAO, support the absence of a field at somewhat lower precision. The new method is very efficient; it is shown that for suitable DA stars the integration time, with ESPaDOnS on a 3.6-m telescope, to reach a 500 G standard error on a white dwarf of V = 12.5, is about half an hour, about the same as the time required on an ESO 8-m telescope with FORS using conventional low-resolution spectropolarimetry.
MAGNETAR GIANT FLARES AND THEIR PRECURSORS—FLUX ROPE ERUPTIONS WITH CURRENT SHEETS

We propose a catastrophic magnetospheric model for magnetar precursors and their successive giant flares. Axisymmetric models of the magnetosphere, which contain both a helically twisted flux rope and a current sheet, are established based on force-free field configurations. In this model, the helically twisted flux rope would lose its equilibrium and erupt abruptly in response to the slow and quasi-static variations at the ultra-strongly magnetized neutron star's surface. In a previous model without current sheets, only one critical point exists in the flux rope equilibrium curve. New features show up in the equilibrium curves for the flux rope when current sheets appear in the magnetosphere. The causal connection between the precursor and the giant flare, as well as the temporary re-entry of the quiescent state between the precursor and the giant flare, can be naturally explained. Magnetic energy would be released during the catastrophic state transitions. The detailed energetics of the model are also discussed. The current sheet created by the catastrophic loss of equilibrium of the flux rope provides an ideal place for magnetic reconnection. We point out the importance of magnetic reconnection for further enhancement of the energy release during eruptions.
Exact maps in density functional theory for lattice models

In the present work, we employ exact diagonalization for model systems on a real-space lattice to explicitly construct the exact density-to-potential and graphically illustrate the complete exact density-to-wavefunction map that underly the Hohenberg–Kohn theorem in density functional theory. Having the explicit wavefunction-to-density map at hand, we are able to construct arbitrary observables as functionals of the ground-state density. We analyze the density-to-potential map as the distance between the fragments of a system increases and the correlation in the system grows. We observe a feature that gradually develops in the density-to-potential map as well as in the density-to-wavefunction map. This feature is inherited by arbitrary expectation values as functional of the ground-state density. We explicitly show the excited-state energies, the excited-state densities, and the correlation entropy as functionals of the ground-state density. All of them show this exact feature that sharpens as the coupling of the fragments decreases and the correlation grows. We denominate this feature as intra-system steepening and discuss how it relates to the well-known inter-system derivative discontinuity. The inter-system derivative discontinuity is an exact concept for coupled subsystems with degenerate ground state. However, the coupling between subsystems as in charge transfer processes can lift the degeneracy. An important conclusion is that for such systems with a near-degenerate ground state, the corresponding cut along the particle number N of the exact density functionals is differentiable with a well-defined gradient near integer particle number.
Asymptotic late-time tails of massive spin-2 fields

The late-time dynamics of massive spin-2 fields in flat and curved spacetimes are studied analytically. We find that the time evolutions of the massive fields are characterized by oscillatory power-law decaying tails at asymptotically late times. In a flat spacetime the decaying exponent depends on the multipole number and the parity of the mode. In the curved Schwarzschild black-hole spacetime the decaying exponent is found to be universal.
Variable neutron star free precession in Hercules X-1 from evolution of RXTE X-ray pulse profiles with phase of the 35-d cycle

Accretion of matter onto the surface of a freely precessing n eutron star with a complex non-dipole magnetic field can explain the change of X-ray pul se profiles of Her X-1 observed by RXTE with the phase of the 35-day cycle. We demonstrate this using all available measurements of X-ray pulse profiles in the 9-13 keV energy range obtained with the RXTE/PCA. The measured profiles guided the elaboration of a geometrica l model and the definition of locations of emitting poles, arcs, and spots on the NS surface which satisfactorily reproduce the observed pulse profiles and their dependence on free precess ion phase. We have found that the observed trend of the times of the 35-day turn-ons on the O-C diagram, which can be approximated by a collection of consecutive linear segments around the mean value, can be described by our model by assuming a variable free precession period, with a fractional period change of about a few percent. Under this assumption and using our model, we have found that the times of phase zero of the neutron star free precession (whic h we identify with the maximum separation of the brightest spot on the neutron star surface with the NS spin axis) occur about 1.6 days after the the mean turn-on times inside each ’stable ’ epoch, producing a linear trend on the O-C diagram with the same slope as the observed times of turn-ons. We propose that the 2.5% changes in the free precession period that occur on time scales of several to tens of 35-day cycles can be related to wandering of the principal in ertia axis of the NS body due to variations in the patterns of accretion onto the NS surface. The closeness of periods of the disk precession and the NS free precession can be explained by the presence of a synchronization mechanism in the system, which modulates the dynamical interaction of the gas streams and the accretion disk with the NS free precession period.
Strong Instability of Ground States to a Fourth Order Schrödinger Equation

In this note, we prove the instability by blow-up of the ground state solutions for a class of fourth order Schrodinger equations. This extends the first rigorous results on blowing-up solutions for the biharmonic nonlinear Schrodinger due to Boulenger and Lenzmann [8] and confirm numerical conjectures from [1–3, 11].
Fundamentals of Geometrothermodynamics

We present the basic mathematical elements of geometrothermodynamics which is a formalism developed to describe in an invariant way the thermodynamic properties of a given thermodynamic system in terms of geometric structures. First, in order to represent the first law of thermodynamics and the general Legendre transformations in an invariant way, we define the phase manifold as a Legendre invariant Riemannian manifold with a contact structure. The equilibrium manifold is defined by using a harmonic map which includes the specification of the fundamental equation of the thermodynamic system. Quasi-static thermodynamic processes are shown to correspond to geodesics of the equilibrium manifold which preserve the laws of thermodynamics. We study in detail the equilibrium manifold of the ideal gas and the van der Waals gas as concrete examples of the application of geometrothermodynamics.
Probing the Galactic Origin of the IceCube Excess with Gamma-Rays

The IceCube Collaboration has recently reported evidence for a high-energy extraterrestrial neutrino flux. During two years of operation 28 events with energies between 30 TeV and 1.2 PeV were observed while only 10.6 events were expected from conventional atmospheric backgrounds. The hadronic interactions responsible for this IceCube excess will also produce a flux of high-energy gamma-rays that can serve as a probe of source direction and distance. We show that existing TeV to PeV diffuse gamma-ray limits support the interpretation that the IceCube excess is mostly of extragalactic origin. However, we point out that gamma-ray surveys are biased in the Northern Hemisphere whereas the recent IceCube data tentatively show a weak preference for the Southern Sky. Possible sub-dominant contributions from Galactic neutrino sources like remnants of supernovae and hypernovae are marginally consistent with present gamma-ray limits. This emphasizes the importance of future diffuse TeV to PeV gamma-ray surveys in the Southern Hemisphere, particularly in the extended region around the Galactic Center including the Fermi Bubbles.
A NEW MODEL FOR DARK MATTER HALOS HOSTING QUASARS

A new model for quasar-hosting dark matter halos, meeting two physical conditions, is put forth. First, significant interactions are taken into consideration to trigger quasar activities. Second, satellites in very massive halos at low redshift are removed from consideration due to their deficiency in cold gas. We analyze the Millennium Simulation to find halos that meet these two conditions and simultaneously match two-point auto-correlation functions of quasars and cross-correlation functions between quasars and galaxies at z = 0.5–3.2. The masses of the quasar hosts found decrease with decreasing redshift, with the mass thresholds being [(2–5) × 1012, (2–5) × 1011, (1–3) × 1011] M☉ for median luminosities of ∼[1046, 1046, 1045] erg s−1 at z = (3.2, 1.4, 0.53), respectively, an order of magnitude lower than those inferred based on halo occupation distribution modeling. In this model, quasar hosts are primarily massive central halos at z ⩾ 2–3 but increasingly dominated by lower mass satellite halos experiencing major interactions toward lower redshift. However, below z = 1, satellite halos in groups more massive than ∼2 × 1013 M☉ do not host quasars. Whether for central or satellite halos, imposing the condition of significant interactions substantially boosts the clustering strength compared to the total population with the same mass cut. The inferred lifetimes of quasars at z = 0.5–3.2 of 3–30 Myr are in agreement with observations. Quasars at z ∼ 2 would be hosted by halos of mass ∼5 × 1011 M☉ in this model, compared to ∼3 × 1012 M☉ previously thought, which would help reconcile with the observed, otherwise puzzling high covering fractions for Lyman limit systems around quasars.
Adversarial U-net with spectral normalization for histopathology image segmentation using synthetic data

Automated segmentation of tissue and cellular structure in H&E images is an important first step towards automated histopathology slide analysis. For example, nuclei segmentation can aid with detecting pleomorphism and epithelium segmentation can aid in identification of tumor infiltrating lymphocytes etc. Existing deep learning-based approaches are often trained organ-wise and lack diversity of training data for multi-organ segmentation networks. In this work, we propose to augment existing nuclei segmentation datasets using cycleGANs. We learn an unpaired mapping from perturbed randomized polygon masks to pseudo-H&E images. We generate over synthetic H&E patches from several different organs for nuclei segmentation. We then use an adversarial U-Net with spectral normalization for increased training stability for segmentation. This paired image-to-image translation style network not only learns the mapping form H&E patches to segmentation masks but also learns an optimal loss function. Such an approach eliminates the need for a hand-crafted loss which has been explored significantly for nuclei segmentation. We demonstrate that the average accuracy for multi-organ nuclei segmentation increases to 94.43% using the proposed synthetic data generation and adversarial U-Net-based segmentation pipeline as compared to 79.81% when no synthetic data and adversarial loss was used.