Miracle-dz/UniFAR-FTUs huggingface dataset:
Shear-induced Opening of the Coronal Magnetic Field

This work describes the evolution of a model solar corona in response to motions of the footpoints of its magnetic field. The mathematics involved is semianalytic, with the only numerical solution being that of an ordinary differential equation. This approach, while lacking the flexibility and physical details of full MHD simulations, allows for very rapid computation along with complete and rigorous exploration of the model's implications. We find that the model coronal field bulges upward, at first slowly and then more dramatically, in response to footpoint displacements. The energy in the field rises monotonically from that of the initial potential state, and the field configuration and energy appraoch asymptotically that of a fully open field. Concurrently, electric currents develop and concentrate into a current sheet as the limiting case of the open field is approached. Examination of the equations shows rigorously that in the asymptotic limit of the fully open field, the current layer becomes a true ideal MHD singularity.
A Rarely Seen Taxonomic Revision with Immense Value for 41 Years and Counting: Reflections on the 1981 Monograph of Trichonta Winnertz, 1864 (Diptera: Mycetophilidae) by Raymond Gagné, with an Integrative Revision of the Trichonta Vulcani (Dziedzicki, 1889) Species Complex

Abstract. We celebrate Raymond J. Gagné for his contributions to taxonomy of the Mycetophilidae (Diptera), specifically for his forty-one-years-old monograph of Holarctic Trichonta Winnertz, 1864 that is still the primary source used for species identification in the genus. We briefly reflect on his monograph's impact and demonstrate by use of recent DNA barcode data extracted from BOLD Systems (BOLD) that the model for the distribution of Holarctic Mycetophilidae that Gagné presented in the monograph still holds up to scrutiny. To demonstrate the refined species concept now being applied by use of an integrative taxonomic approach that includes DNA barcodes, we revise a small, but distinct, species complex that Gagné recognized as one morphologically defined species and used as an example of an old pan-Holarctic taxon, Trichonta vulcani (Dziedzicki, 1889). We find the Trichonta vulcani species complex (sensu Kallweit 1998) to consist of at least six species in the Holarctic Region of which three are being described as new to science: Trichonta japonica Kurina, new species (East Palearctic), Trichonta neovulcani Kjaerandsen, new species (East Nearctic), Trichonta raymondgagnei Kjaerandsen, new species (Holarctic), Trichonta trifida Lundstrom, 1909 (wide Palearctic), Trichonta tristis (Strobl, 1898) (wide Palearctic), and Trichonta vulcani (Dziedzicki, 1889) (wide Palearctic). All six species are distinctly separated by DNA barcodes that correspond well to minor, but constant, differences in their male terminalia. However, one of the widespread species, Trichonta trifida, displays some genetic and morphological differentiation between western and eastern Palaearctic populations. We presently consider these populations conspecific pending broader sampling. We further propose a replacement name Trichonta nepalensis Kjaerandsen, new name for Trichonta superba Gagné, 1981, a junior primary homonym of Trichonta superba Ostroverkhova, 1979, the latter being a junior secondary synonym of Trichonta tristis (Strobl, 1898).
Instability and symmetry breaking of surfactant films over an air bubble

Abstract We examine the asymmetric flows of aqueous surfactant films over an air bubble. A thin film is formed by raising an equilibrated air bubble through an aqueous solution of Triton X-100 (0.01 mM, below critical micelle concentration). Due to the advection generated by the squeezing motion, the initially uniformly distributed surfactants redistribute and, thus, generate an axisymmetric surface tension gradient that drives a Marangoni flow. The external forcing of raising the bubble also creates an axisymmetric dimpled film with a radial thickness variation that reaches its minimum at the rim of the dimple. The curvature in the film thickness generates an axisymmetric capillary pressure driven flow. When the apex of the bubble has penetrated the initially flat air-solution interface, the rising bubble is stopped and the resulting flow demonstrates symmetry breaking both in the experiment and in the parameter matched numerical simulation. Linear stability analysis reveals the mechanism behind the disturbance growth. It is found that the most dangerous azimuthal wavenumber scales linearly with the ratio of the rim radius to the radial width of significant radial pressure and surface tension gradients after stopping the bubble. Finally, we compare this instability to the previously studied surfactant spreading induced fingering phenomenon (Warner, Craster & Matar, Phys. Fluids, vol. 16, issue 8, 2004, pp. 2933–2951).
Using quantitative methods to understand leaf epidermal development

Abstract Abstract As the interface between plants and the environment, the leaf epidermis provides the first layer of protection against drought, ultraviolet light, and pathogen attack. This cell layer comprises highly coordinated and specialised cells such as stomata, pavement cells and trichomes. While much has been learned from the genetic dissection of stomatal, trichome and pavement cell formation, emerging methods in quantitative measurements that monitor cellular or tissue dynamics will allow us to further investigate cell state transitions and fate determination in leaf epidermal development. In this review, we introduce the formation of epidermal cell types in Arabidopsis and provide examples of quantitative tools to describe phenotypes in leaf research. We further focus on cellular factors involved in triggering cell fates and their quantitative measurements in mechanistic studies and biological patterning. A comprehensive understanding of how a functional leaf epidermis develops will advance the breeding of crops with improved stress tolerance.
Jetting onset on a liquid surface accelerated past a submerged cylinder

Abstract A novel experiment is presented to study the initial disturbances on a free surface due to the constant acceleration of liquid around a submerged obstacle. The surface response to different obstacle sizes, initial surface heights and fluid velocities is measured using high-speed videography. Perturbations observed on the surface are classified into either jetting or gravity waves by measuring the steepness of growing liquid columns. A classification phase map between these two regimes is obtained and compared with analytical results by Martín Pardo and Nedić (2021). The agreement between decision boundaries is good for high Froude numbers (high fluid velocities) but deteriorates at lower velocities, where viscosity and surface tension effects (not considered in the analytical model) have a greater predominance. The surface profile and perturbation amplitude measured in experiments are also compared against this analytical model. In all cases, the model accurately predicts the corresponding experimental results at the beginning of the motion, but the prediction error increases with time. It is also observed that faster moving surfaces that lead to the onset of jetting have greater prediction accuracies and longer validity times of the predictions.
Development of a Three-Dimensional Spectral Linear Baroclinic Model and its Application to the Baroclinic Instability Associated with Positive and Negative Arctic Oscillation Indices

In this study, a linear baroclinic model (LBM) is developed from a three-dimensional (3D) spectral primitive equation model. With this LBM, we investigate the linear stability problem for various zonally varying basic states on a sphere. For a zonal climate basic state, we confirm that the traditional Charney and dipole Charney modes appear as the most dominant unstable modes in the synoptic to planetary scales. For a zonally varying basic state, we find that these unstable modes are modified by the regionality of the local baroclinicity of the basic state. Given the zonally varying barotropic basic state, we find that the barotropically most unstable standing mode appears to be the Arctic Oscillation (AO)mode. In this study, the eigensolution of the LBM is regarded as a generalized extension at the 3D normal mode at the motionless atmosphere to those of an arbitrary climate basic state. As an application of the LBM, various zonally varying basic states associated with the positive and negative AO indices are substituted into the LBM to find the response of the baroclinic eddies. According to the result, the positive feedback dominates in the Atlantic sector for positive AO index because of the presence of enhanced double-jet structure. When the AO index is negative, the eddy momentum flux converges in the mid-latitudes to shift the subtropical jet poleward in the Atlantic and Pacific sectors because of the intensified baroclinic instability. The positive feedback operates in a different way in the Atlantic and Pacific sectors depending on their double or single westerly jets. It is concluded that the baroclinically unstable modes are modified by the positive/negative AO index, so that the induced local eddy momentum flux shows a positive feedback to the AO.
Amorphous Solid without Low Energy Excitations

We have measured the low temperature internal friction (Q{sup -1}) of amorphous silicon (a-Si) films. {ital e}-beam evaporation or {sup 28}Si{sup +} implantation leads to the temperature-independent Q{sup -1}{sub 0} plateau common to all amorphous solids. For hydrogenated amorphous silicon with 1 at. {percent} H produced by hot wire chemical vapor deposition, however, Q{sup -1}{sub 0} is over 200 times smaller than for {ital e}-beam {ital a}-Si. This is the first observation of an amorphous solid without any significant low energy excitations. It offers the opportunity to study amorphous solids containing controlled densities of tunneling defects, and thus to explore their nature. {copyright} {ital 1997} {ital The American Physical Society}
Tuneman: Customizing Networks to Guarantee Application Bandwidth and Latency

We examine how to provide applications with dedicated bandwidth and guaranteed latency in a programmable mission-critical network. Unlike other SDN approaches such as B4 or SWAN, our system Tuneman optimizes both routes and packet schedules at each node to provide flows with sub-second bandwidth changes. Tuneman uses node-level optimization to compute node schedules in a slotted switch and does dynamic routing using a search procedure with Quality of Service– (QoS) based weights. This allows Tuneman to provide an efficient solution for mission-critical networks that have stringent QoS requirements. We evaluate Tuneman on a telesurgery network using a switch prototype built using FPGAs and also via simulations on India’s Tata Network. For mission-critical networks with multiple QoS levels, Tuneman has comparable or better utilization than SWAN while providing delay bounds guarantees.
Further Evidence of a Continuum in the Clinical Spectrum of Dominant PIEZO2-Related Disorders and Implications in Cerebellar Anomalies

Introduction: Pathogenic variants in the PIEZO family member 2 (PIEZO2) gene are known to cause Gordon syndrome (GS), Marden-Walker syndrome (MWS), and distal arthrogryposis type 5 (DA5). Out of these, MWS has a recognizable phenotype that can be discerned easily, but the distinction between GS and DA5 is less evident. Few children with pathogenic PIEZO2 variants have been reported to show posterior fossa anomalies. Methods and Results: By candidate gene targeting guided by proper clinical evaluation and neuroimaging findings, a patient with classic MWS harboring a de novo novel variant (c.8237G>A, p.W2746*) in the C-terminal region of PIEZO2 was identified. In addition, another girl with the typical clinical features of GS is also described carrying the most prevalent reported variant (c.8057G>A, p.R2686H) in PIEZO2. The brain MRI of the 2 patients showed Dandy-Walker malformation (DWM). Diffusion tensor imaging visualized anteroposterior and downward aligned thin middle cerebellar peduncle. The association of DWM with arthrogryposis in the presence of PIEZO2 variants remains quite interesting and provides more evidence that PIEZO2 plays a role in the development of hindbrain although the underlying mechanism remains unclear. Moreover, the 2 girls had distinct foot patterning in the form of shortening of the first and fifth toes. Conclusion: Phenotype analysis and a comprehensive review of the literature strongly support the previously published data and corroborate the evidence that heterozygous PIEZO2-related disorders represent a continuum with overlapping phenotypic features.
Positron scattering from argon: total cross sections and the scattering length

We report results from new positron–argon total cross-section (TCS) measurements. Agreement with the corresponding recent data of Jones et al (2011 Phys. Rev. A 83 032701) is found to be very good, except at the lowest energies of common measurement. Excellent qualitative agreement is also found between our measurements and an improved convergent close-coupling (CCC) calculation which was undertaken as a part of this study. This level of accord between our experimental and theoretical TCSs has enabled us to determine an experimental scattering length (a) of a = −4.9 ± 0.7 au for the positron–argon system. That value is in excellent agreement with the relativistic polarized orbital optical potential approach result of Jones et al (a = −4.7 au) and our CCC result of a = −4.3 au.
When women enter male-dominated territories in the platform economy: gender inequalities among drivers and riders in Argentina

ABSTRACT Platform labour, especially when it comes to its flexible schedules, may represent a job insertion possibility and a source of income for many women. However, such opportunities are not exempted from gender bias. This article inspects how the expansion of the platform economy affects gender inequalities by focusing on two platform occupations: ride-hailing and delivery services. First, it investigates gender gaps in terms of working hours and earnings via linear regression as well as their determinants. Second, qualitative data further deepen the analysis of female riders’ and drivers’ experience in male-dominated territories, exploring how it is perceived and endured by workers. This paper is based on qualitative and quantitative data collected in the metropolitan area of Buenos Aires between 2019 and 2021. The analysis suggests that the gender-differentiated economic performance of riders and drivers is associated with demographic and on-the-job characteristics, implying restrictions for women workers in terms of how long, where, and when they can work. Algorithmic management further reinforces these initial female disadvantages, through tools such as scoring systems, dynamic pricing, and selective work allocation. The article concludes by providing some insights into a gender-transformative approach to the future regulation of these activities.
Tracing Vowel Quality in Iraqi Arabic Dialects: A Typological Study

Iraqi Arabic dialects have a range of phoneme inventories, and there is a necessity for tracing the distribution of phonological features of such phonemes within these dialects. Three dialects were investigated to trace variations in vowel quality tracking any distribution patterns or deviations. The first three formants were extracted and analyzed with the application of a number of statistical methods. It is shown that a correlation is evident among the formants of qeltu and gelet dialects with a strong correlation between short and long vowels within and across dialects for two age categories. While the results of ANOVA and MANOVA techniques show a significant interaction of F1 and F2 across dialects. It is crucial to say that a pattern of variation in vowel quality is diagnosed among Iraqi Arabic dialects.
Must the photon mass be zero?

SummaryThe hold query concerning longitudinal waves, which already beset the elastic theory of light, has in our day revived in the form expressed in the title. Maxwell’s field laws are a singular limiting case in that they admit but transversal waves. If this held only in however close an approximation, some fundamental laws of radiation would seem to be affected by a factor 3/2, on account of the « third degree of freedom ». If so, this would render even Maxwell’s theory suspect, for we are loath to accept as an adequate description of nature a limiting case whose predictions differ grossly and discontinuously from those reached by a sufficiently close approach to the limit. We show here in the simple, if fictitious, example of an ideal conductor, that by extending Proca’s field equations in a plausible fashion to the interior of matter the discontinuity is avoided and the correct factors (not 3/2-thereof) are already reached with a rest-mass at the upper limit, imposed anyhow by other well-known considerations.
Attention weights accurately predict language representations in the brain

In Transformer-based language models (LMs) the attention mechanism converts token embeddings into contextual embeddings that incorporate information from neighboring words. The resulting contextual hidden state embeddings have enabled highly accurate models of brain responses, suggesting that the attention mechanism constructs contextual embeddings that carry information reflected in language-related brain representations. However, it is unclear whether the attention weights that are used to integrate information across words are themselves related to language representations in the brain. To address this question we analyzed functional magnetic resonance imaging (fMRI) recordings of participants reading English language narratives. We provided the narrative text as input to two LMs (BERT and GPT-2) and extracted their corresponding attention weights. We then used encoding models to determine how well attention weights can predict recorded brain responses. We find that attention weights accurately predict brain responses in much of the frontal and temporal cortices. Our results suggest that the attention mechanism itself carries information that is reflected in brain representations. Moreover, these results indicate cortical areas in which context integration may occur.
The effect of random and systematic visual stimulation on entrained infraslow quasi-periodic dynamic global waves in human brain activity

Infraslow (<0.1Hz) electric activity, involved in attention and arousal fluctuations, serves as the unique neurophysiological basis for infraslow BOLD fluctuations. Particularly, the dynamics of infraslow electrical activity in both resting and task-performing human brains exhibit a quasi-periodic pattern (QPP) of consistent, phase-locked spatiotemporal BOLD signal changes across the whole brain. However, it is unclear how environmental stimuli affect the infraslow dynamic QPP or how the ongoing infraslow dynamics might modify the response to the environment in awake humans. To investigate this, we presented checkerboard sequences flashing at 8Hz to subjects. This is a salient visual stimulus that is known to produce a strong response in visual processing regions. Three central questions were investigated: 1) how does visual stimulation affect the QPPs compared to rest, 2) how does variability in visual stimulus onset affect the QPPs, and 3) how does the BOLD response to visual stimuli depend on the phases of the QPPs. Two different visual stimulation sequences were employed, a systematic stimulation sequence in which the visual stimulus appeared every 20.3 secs and a random stimulation sequence in which the visual stimulus occurred randomly every 14~62.3 secs. Three central observations emerged. First, the two different stimulation sequences affect the QPP waveform in different ways, i.e., the systematic one affecting more on its phase and the random one affecting more on its amplitude. Second, the QPP was more frequent in the systematic condition with significantly shorter intervals between consecutive QPPs compared to the random condition. Third, the BOLD signal response to the visual stimulus across both conditions was swamped by the QPP at the stimulus onset. These results provide novel insights into the relationship between infraslow intrinsic dynamics and task-evoked brain activity.
Mega-scale movie-fields in the mouse visuo-hippocampal network

Natural experience often involves a continuous series of related images while the subject is immobile. How does the cortico-hippocampal circuit process this information? The hippocampus is crucial for episodic memory1–3, but most rodent single unit studies require spatial exploration4–6 or active engagement7. Hence, we investigated neural responses to a silent, isoluminant, black and white movie in head-fixed mice without any task or locomotion demands, or rewards, from the Allen Brain Observatory. The activity of most neurons (97%, 6554/6785) in the thalamo-cortical visual areas was significantly modulated by the 30s long movie clip. Surprisingly, a third (33%, 3379/10263) of hippocampal –dentate gyrus, CA1 and subiculum– neurons showed movie-selectivity, with elevated firing in specific movie sub-segments, termed movie-fields. Movie-tuning remained intact when mice were immobile or ran spontaneously. On average, a tuned cell had more than 5 movie-fields in visual areas, but only 2 in hippocampal areas. The movie-field durations in all brain regions spanned an unprecedented 1000-fold range: from 0.02s to 20s, termed mega-scale coding. Yet, the total duration of all the movie-fields of a cell was comparable across neurons and brain regions. We hypothesize that hippocampal responses show greater continuous-sequence encoding than visual areas, as evidenced by fewer and broader movie-fields than in visual areas. Consistent with this hypothesis, repeated presentation of the movie images in a fixed, scrambled sequence virtually abolished hippocampal but not visual-cortical selectivity. The enhancement of continuous movie tuning compared to the scrambled sequence was eight-fold greater in hippocampal than visual areas, further supporting episodic-sequence encoding. Thus, all mouse-brain areas investigated encoded segments of the movie. Similar results are likely to hold in primates and humans. Hence, movies could provide a unified way to probe neural mechanisms of episodic information processing and memory, even in immobile subjects, across brain regions, and species.