Miracle-dz/UniFAR-FTUs huggingface dataset:
Adversarial cycle-consistent synthesis of cerebral microbleeds for data augmentation

We propose a novel framework for controllable pathological image synthesis for data augmentation. Inspired by CycleGAN, we perform cycle-consistent image-to-image translation between two domains: healthy and pathological. Guided by a semantic mask, an adversarially trained generator synthesizes pathology on a healthy image in the specified location. We demonstrate our approach on an institutional dataset of cerebral microbleeds in traumatic brain injury patients. We utilize synthetic images generated with our method for data augmentation in cerebral microbleeds detection. Enriching the training dataset with synthetic images exhibits the potential to increase detection performance for cerebral microbleeds in traumatic brain injury patients.
To Understand Representation of Layer-aware Sequence Encoders as Multi-order-graph

In this paper, we propose an explanation of representation for self-attention network (SAN) based neural sequence encoders, which regards the information captured by the model and the encoding of the model as graph structure and the generation of these graph structures respectively. The proposed explanation applies to existing works on SAN-based models and can explain the relationship among the ability to capture the structural or linguistic information, depth of model, and length of sentence, and can also be extended to other models such as recurrent neural network based models. We also propose a revisited multigraph called Multi-order-Graph (MoG) based on our explanation to model the graph structures in the SAN-based model as subgraphs in MoG and convert the encoding of SAN-based model to the generation of MoG. Based on our explanation, we further introduce a Graph-Transformer by enhancing the ability to capture multiple subgraphs of different orders and focusing on subgraphs of high orders. Experimental results on multiple neural machine translation tasks show that the Graph-Transformer can yield effective performance improvement.
Spectroscopic observations of a flare-related coronal jet

Coronal jets are ubiquitous in active regions (ARs) and coronal holes. In this paper, we study a coronal jet related to a C3.4 circular-ribbon flare in active region 12434 on 2015 October 16. Two minifilaments were located under a 3D fan-spine structure before flare. The flare was generated by the eruption of one filament. The kinetic evolution of the jet was divided into two phases: a slow rise phase at a speed of $\sim$131 km s$^{-1}$ and a fast rise phase at a speed of $\sim$363 km s$^{-1}$ in the plane-of-sky. The slow rise phase may correspond to the impulsive reconnection at the breakout current sheet. The fast rise phase may correspond to magnetic reconnection at the flare current sheet. The transition between the two phases occurred at $\sim$09:00:40 UT. The blueshifted Doppler velocities of the jet in the Si {\sc iv} 1402.80 {\AA} line range from -34 to -120 km s$^{-1}$. The accelerated high-energy electrons are composed of three groups. Those propagating upward along open field generate type \textrm{III} radio bursts, while those propagating downward produce HXR emissions and drive chromospheric condensation observed in the Si {\sc iv} line. The electrons trapped in the rising filament generate a microwave burst lasting for $\le$40 s. Bidirectional outflows at the base of jet are manifested by significant line broadenings of the Si {\sc iv} line. The blueshifted Doppler velocities of outflows range from -13 to -101 km s$^{-1}$. The redshifted Doppler velocities of outflows range from $\sim$17 to $\sim$170 km s$^{-1}$. Our multiwavelength observations of the flare-related jet are in favor of the breakout jet model and are important for understanding the acceleration and transport of nonthermal electrons.
Estimating informativeness of samples with Smooth Unique Information

We define a notion of information that an individual sample provides to the training of a neural network, and we specialize it to measure both how much a sample informs the final weights and how much it informs the function computed by the weights. Though related, we show that these quantities have a qualitatively different behavior. We give efficient approximations of these quantities using a linearized network and demonstrate empirically that the approximation is accurate for real-world architectures, such as pre-trained ResNets. We apply these measures to several problems, such as dataset summarization, analysis of under-sampled classes, comparison of informativeness of different data sources, and detection of adversarial and corrupted examples. Our work generalizes existing frameworks but enjoys better computational properties for heavily over-parametrized models, which makes it possible to apply it to real-world networks.
A Novel Registration & Colorization Technique for Thermal to Cross Domain Colorized Images

Thermal images can be obtained as either grayscale images or pseudo colored images based on the thermal profile of the object being captured. We present a novel registration method that works on images captured via multiple thermal imagers irrespective of make and internal resolution as well as a colorization scheme that can be used to obtain a colorized thermal image which is similar to an optical image, while retaining the information of the thermal profile as a part of the output, thus providing information of both domains jointly. We call this a cross domain colorized image. We also outline a new public thermal-optical paired database that we are presenting as a part of this paper, containing unique data points obtained via multiple thermal imagers. Finally, we compare the results with prior literature, show how our results are different and discuss on some future work that can be explored further in this domain as well.
Evaluating User Experiences in Mixed Reality

Measure user experience in MR (i.e., AR/VR) user studies is essential. Researchers apply a wide range of measuring methods using objective (e.g., biosignals, time logging), behavioral (e.g., gaze direction, movement amplitude), and subjective (e.g., standardized questionnaires) metrics. Many of these measurement instruments were adapted from use-cases outside of MR but have not been validated for usage in MR experiments. However, researchers are faced with various challenges and design alternatives when measuring immersive experiences. These challenges become even more diverse when running out-of-the lab studies. Measurement methods of VR experience recently received much attention. For example, research has started embedding questionnaires in the VE for various applications, allowing users to stay closer to the ongoing experience while filling out the survey. However, there is a diversity in the interaction methods and practices on how the assessment procedure is conducted. This diversity in methods underlines a missing shared agreement of standardized measurement tools for VR experiences. AR research strongly orients on the research methods from VR, e.g., using the same type of subjective questionnaires. However, some crucial technical differences require careful considerations during the evaluation. This workshop at CHI 2021 provides a foundation to exchange expertise and address challenges and opportunities of research methods in MR user studies. By this, our workshop launches a discussion of research methods that should lead to standardizing assessment methods in MR user studies. The outcomes of the workshop will be aggregated into a collective special issue journal article.
Flux variability from ejecta in structured relativistic jets with large-scale magnetic fields

Context. Standing and moving shocks in relativistic astrophysical jets are very promising sites for particle acceleration to large Lorentz factors and for the emission from the radio up to the γ-ray band. They are thought to be responsible for at least part of the observed variability in radio-loud active galactic nuclei. Aims. We aim to simulate the interactions of moving shock waves with standing recollimation shocks in structured and magnetized relativistic jets and to characterize the profiles of connected flares in the radio light curve. Methods. Using the relativistic magneto-hydrodynamic code MPI-AMRVAC and a radiative transfer code in post-processing, we explore the influence of the magnetic-field configuration and transverse stratification of an over-pressured jet on its morphology, on the moving shock dynamics, and on the emitted radio light curve. First, we investigate different large-scale magnetic fields with their effects on the standing shocks and on the stratified jet morphology. Secondly, we study the interaction of a moving shock wave with the standing shocks. We calculated the synthetic synchrotron maps and radio light curves and analyze the variability at two frequencies 1 and 15.3 GHz and for several observation angles. Finally, we compare the characteristics of our simulated light curves with radio flares observed from the blazar 3C 273 with the Owens Valley Radio Observatory and Very Long Baseline Array in the MOJAVE survey between 2008 and 2019. Results. We find that in a structured over-pressured relativistic jet, the presence of the large-scale magnetic field structure changes the properties of the standing shock waves and leads to an opening in the jet. The interaction between waves from inner and outer jet components can produce strong standing shocks. When crossing such standing shocks, moving shock waves accompanying overdensities injected in the base of the jet cause very luminous radio flares. The observation of the temporal structure of these flares under different viewing angles probes the jet at different optical depths. At 1 GHz and for small angles, the self-absorption caused by the moving shock wave becomes more important and leads to a drop in the observed flux after it interacts with the brightest standing knot. A weak asymmetry is seen in the shape of the simulated flares, resulting from the remnant emission of the shocked standing shocks. The characteristics of the simulated flares and the correlation of peaks in the light curve with the crossing of moving and standing shocks favor this scenario as an explanation of the observed radio flares of 3C 273.
Fuzzy Dark Matter and the 21 cm Power Spectrum

We model the 21 cm power spectrum across the Cosmic Dawn and the Epoch of Reionization (EoR) in fuzzy dark matter (FDM) cosmologies. The suppression of low-mass halos in FDM models leads to a delay in the onset redshift of these epochs relative to cold dark matter (CDM) scenarios. This strongly impacts the 21 cm power spectrum and its redshift evolution. The 21 cm power spectrum at a given stage—i.e., compared at fixed average brightness temperature but varying redshift—of the EoR/Cosmic Dawn process is also modified: in general, the amplitude of 21 cm fluctuations is boosted by the enhanced bias factor of galaxy-hosting halos in FDM. We forecast the prospects for discriminating between CDM and FDM with upcoming power spectrum measurements from HERA, accounting for degeneracies between astrophysical parameters and dark matter properties. If FDM constitutes the entirety of the dark matter and the FDM particle mass is 10−21 eV, HERA can determine the mass to within 20% at 2σ confidence.
Specific heat of 
CeRhIn5
 in high magnetic fields: Magnetic phase diagram revisited

CeRhIn5 is a prototypical antiferromagnetic heavy-fermion compound, whose behavior in a magnetic field is unique. A magnetic field applied in the basal plane of the tetragonal crystal structure induces two additional phase transitions. When the magnetic field is applied along, or close to, the c axis, a new phase characterized by a pronounced in-plane electronic anisotropy emerges at B∗ ≈ 30 T, well below the critical field, Bc ' 50 T, to suppress the antiferromagnetic order. The exact origin of this new phase, originally suggested to be an electronic-nematic state, remains elusive. Here we report low-temperature specific heat measurements in CeRhIn5 in high static magnetic fields up to 36 T applied along both the a and c axes. For fields applied along the a axis, we confirmed the previously suggested phase diagram, and extended it to higher fields. This allowed us to observe a triple point at ∼ 30 T, where the first-order transition from an incommensurate to commensurate magnetic structure merges into the onset of the second-order antiferromagnetic transition. For fields applied along the c axis, we observed a small but distinct anomaly at B∗, which we discuss in terms of a possible field-induced transition, probably weakly first-order. We further suggest that the transition corresponds to a change of magnetic structure. We revise magnetic phase diagrams of CeRhIn5 for both principal orientations of the magnetic field based entirely on thermodynamic anomalies.
Space-time block preconditioning for incompressible flow

Parallel-in-time methods have become increasingly popular in the simulation of time-dependent numerical PDEs, allowing for the efficient use of additional MPI processes when spatial parallelism saturates. Most methods treat the solution and parallelism in space and time separately. In contrast, all-at-once methods solve the full space-time system directly, largely treating time as simply another spatial dimension. All-at-once methods offer a number of benefits over separate treatment of space and time, most notably significantly increased parallelism and faster time-to-solution (when applicable). However, the development of fast, scalable all-at-once methods has largely been limited to time-dependent (advection-)diffusion problems. This paper introduces the concept of space-time block preconditioning for the all-at-once solution of incompressible flow. By extending well-known concepts of spatial block preconditioning to the space-time setting, we develop a block preconditioner whose application requires the solution of a space-time (advection-)diffusion equation in the velocity block, coupled with a pressure Schur complement approximation consisting of independent spatial solves at each time-step, and a space-time matrix-vector multiplication. The new method is tested on four classical models in incompressible flow. Results indicate perfect scalability in refinement of spatial and temporal mesh spacing, perfect scalability in nonlinear Picard iterations count when applied to a nonlinear Navier-Stokes problem, and minimal overhead in terms of number of preconditioner applications compared with sequential time-stepping.
On the Differentially Private Nature of Perturbed Gradient Descent

We consider the problem of empirical risk minimization given a database, using the gradient descent algorithm. We note that the function to be optimized may be non-convex, consisting of saddle points which impede the convergence of the algorithm. A perturbed gradient descent algorithm is typically employed to escape these saddle points. We show that this algorithm, that perturbs the gradient, inherently preserves the privacy of the data. We then employ the differential privacy framework to quantify the privacy hence achieved. We also analyze the change in privacy with varying parameters such as problem dimension and the distance between the databases.
Scope Out Multiband Gravitational-Wave Observations of GW190521-Like Binary Black Holes with Space Gravitational Wave Antenna B-DECIGO

The gravitational wave event, GW190521, is the most massive binary black hole merger observed by ground-based gravitational wave observatories LIGO/Virgo to date. While the observed gravitational wave signal is mainly in the merger and ringdown phases, the inspiral gravitational wave signal of the GW190521-like binary will be more visible to space-based detectors in the low-frequency band. In addition, the ringdown gravitational wave signal will be louder in the next generation (3G) of ground-based detectors in the high-frequency band, displaying the great potential of multiband gravitational wave observations. In this paper, we explore the scientific potential of multiband observations of GW190521-like binaries with a milli-Hz gravitational wave observatory: LISA; a deci-Hz observatory: B-DECIGO; and (next generation of) hecto-Hz observatories: aLIGO and ET. In the case of quasicircular evolution, the triple-band observations of LISA, B-DECIGO, and ET will provide parameter estimation errors of the masses and spin amplitudes of component black holes at the level of order of 1–10%. This would allow consistency tests of general relativity in the strong field at an unparalleled precision, particularly with the “B-DECIGO + ET” observation. In the case of eccentric evolution, the multiband signal-to-noise ratio found in “B-DECIGO + ET” observation would be larger than 100 for a five-year observation prior to coalescence, even with high final eccentricities.
A statistical theory of heavy atoms: Asymptotic behavior of the energy and stability of matter

We give the asymptotic behavior of the ground state energy of Engel's and Dreizler's relativistic Thomas-Fermi-Weizs\"acker-Dirac functional for heavy atoms for fixed ratio of the atomic number and the velocity of light. Using a variation of the lower bound, we show stability of matter.
Vowel errors produced by preschool-age children on a single-word test of articulation

ABSTRACT Eighty-four children, age 4–5 years, with and without speech sound disorder (SSD) completed a battery of standardized speech and language tests, including the Goldman-Fristoe Test of Articulation, Third Edition (GFTA-3). Children with SSD produced more vowel errors than children with typical speech abilities. Percentage vowels correct and consonant error variability were highly correlated, suggesting that poorly specified phonological representations affect both consonants and vowels within a child’s phonological system. However, the GFTA-3 did not contain sufficient target words to determine full vowel inventory. Using words from the GFTA-3, we present a case study of a child with vowel errors along with a sample analysis of these errors, primarily in terms of consonant-vowel feature interactions. Children who exhibit vowel errors on standardized single-word tests of speech accuracy may benefit from further vowel probes to determine how vowel and consonant errors interact in their phonological systems for more targeted therapy.
Neural correlates of distraction and reappraisal in the family context: Associations with symptoms of anxiety and depression in youth

ABSTRACT Objective: Youth coping is consistently associated with risk and resilience for youth internalizing psychopathology. Integrating questionnaire and experimental methods is an important next step in understanding how youth develop, learn, and implement these skills and to identify possible neurobiological mechanisms that underlie these processes. The current study aims to explore associations among youth self-reported and laboratory-based measures of two methods of coping (distraction and reappraisal). Further, the current study aims to examine associations among neural correlates of distraction and reappraisal with symptoms of anxiety and depression in youth. Methods: Youth (N = 69; M = 12.24, SD = 1.83; 52.9% female) completed self-report measures of secondary control coping (RSQ) and symptoms of anxiety (SCARED) and depression (CES-D) and a laboratory coping task. While completing the task, prefrontal hemodynamic changes were measured using functional near-infrared spectroscopy (fNIRS). Results: Neural activation during reappraisal was significantly negatively correlated with youth anxiety symptoms, and both neural activation and self-reported coping were significant independent predictors of anxiety. Youth self-reported coping was not associated with neural activation during reappraisal or distraction. Conclusions: The measurement of possible neural markers of risk and resilience in youth is an important area of continued research. Identification of possible mechanisms of change related to anxiety and depression in youth may inform targets of intervention.
Levels of burn-out among healthcare workers during the COVID-19 pandemic and their associated factors: a cross-sectional study in a tertiary hospital of a highly burdened area of north-east Italy

Objective To determine burn-out levels and associated factors among healthcare personnel working in a tertiary hospital of a highly burdened area of north-east Italy during the COVID-19 pandemic. Design Observational study conducted from 21 April to 6 May 2020 using a web-based questionnaire. Setting Research conducted in the Verona University Hospital (Veneto, Italy). Participants Out of 2195 eligible participants, 1961 healthcare workers with the full range of professional profiles (89.3%) completed the survey. Primary outcome measure Levels of burn-out, assessed by the Maslach Burnout Inventory-General Survey (MBI-GS). Multivariable logistic regression analysis was performed to identify factors associated with burn-out in each MBI-GS dimension (emotional exhaustion, EX; professional efficacy, EF; cynicism, CY). Results Overall, 38.3% displayed high EX, 46.5% low EF and 26.5% high CY. Burn-out was frequent among staff working in intensive care units (EX 57.0%; EF 47.8%; CY 40.1%), and among residents (EX 34.9%; EF 63.9%; CY 33.4%) and nurses (EX 49.2%; EF 46.9%; CY 29.7%). Being a resident increased the risk of burn-out (by nearly 2.5 times) in all the three MBI subscales and being a nurse increased the risk of burn-out in the EX dimension in comparison to physicians. Healthcare staff directly engaged with patients with COVID-19 showed more EX and CY than those working in non-COVID wards. Finally, the risk of burn-out was higher in staff showing pre-existing psychological problems, in those having experienced a COVID-related traumatic event and in those having experienced interpersonal avoidance in the workplace and personal life. Conclusions Burn-out represents a great concern for healthcare staff working in a large tertiary hospital during the COVID-19 pandemic and its impact is more burdensome for front-line junior physicians. This study underlines the need to carefully address psychological well-being of healthcare workers to prevent the increase of burn-out in the event of a new COVID-19 healthcare emergency.
The dimensionality of early executive functions in young preschoolers: Comparing unidimensional versus bidimensional models and their ecological validity

ABSTRACT The study analyses the dimensionality of executive functions (EF) and its relationship with behavior in typically developing 3- and 4-year-old children. In study 1, confirmatory factor analysis (CFA) was used to investigate the validity of a one-factor model in 117 preschoolers. Since this model was not confirmed, a two-factor model was identified through exploratory factor analysis. In study 2, the validity of the new two-factor versus one-factor model was tested on a new sample of 128 children through a series of CFAs. The relationship between the models and specific behavioral aspects of the children was investigated. The results suggest that a bidimensional structure showed a better fit to the data and more ecological validity than a unitary structure.