Miracle-dz/UniFAR-FTUs huggingface dataset:
Counterexamples in self-testing

In the recent years self-testing has grown into a rich and active area of study with applications ranging from practical verification of quantum devices to deep complexity theoretic results. Self-testing allows a classical verifier to deduce which quantum measurements and on what state are used, for example, by provers Alice and Bob in a nonlocal game. Hence, self-testing as well as its noise-tolerant cousin – robust self-testing – are desirable features for a nonlocal game to have.Contrary to what one might expect, we have a rather incomplete understanding of if and how self-testing could fail to hold. In particular, could it be that every 2-party nonlocal game or Bell inequality with a quantum advantage certifies the presence of a specific quantum state? Also, is it the case that every self-testing result can be turned robust with enough ingeniuty and effort? We answer these questions in the negative by providing simple and fully explicit counterexamples. To this end, given two nonlocal games G1 and G2, we introduce the (G1∨G2)-game, in which the players get pairs of questions and choose which game they want to play. The players win if they choose the same game and win it with the answers they have given. Our counterexamples are based on this game and we believe this class of games to be of independent interest.
Divergence statistics: sampling properties and multinomial goodness of fit and divergence tests

φ-divergence . statistics are obtained by either replacing both distributions involved in the argument of the φ -divergence measure by their sample estimates or replacing one distribution and considering the other as given. The sampling properties of estimated divergence-type measures are investigated. Approximate means and variances are derived and asymptotic distributions are obtained. Tests of goodness of fit of observed frequencies to expected ones and tests of equality of divergences based on two or more multinomial samples are constructed.
Evolutionary ecology of language origins through confrontational scavenging

A dynamic model and an agent-based simulation model implementing the assumptions of the confrontational scavenging hypothesis on early protolanguage as an adaptive response of Homo erectus to gradual change in their habitat has been developed and studied. The core assumptions of the hypothesis and the model scenario are the pre-adaptation of our ancestors to occupy the ecological niche that they constructed for themselves by having evolved displaced communication and a rudimentary tool manufacture, two features allowing them to use a new, concentrated and abundant resource—megafauna carrion—on the savannahs replacing arboreal habitats owing to the drying climate of East Africa at about 2 Ma. The shift in diet required coordinated cooperation by the hominin scavengers confronted with concurrent predators. Power scavenging compelled displaced symbolic communication featuring a limited semantic range; syntax was not yet required. We show that phenotypic evolution on the accuracy of information transfer between cooperating hominins is a necessary and sufficient condition for the population of agents to survive the diet shift. Both the individual and the group fitness of the hominin horde increased with the accuracy of their protolanguage, with decreasing time allocated to foraging and thus more time left for culture. This article is part of the theme issue ‘Human socio-cultural evolution in light of evolutionary transitions’.
The peculiarities of hydrogen bonds in raman spectra of solid superionic polyantimonic acids

Abstract Raman scattering spectra in hydrated antimonium pentaoxide (APO) were measured on two samples with different crystal structure. Essentially higher ionic conductivity of tetragonal modification is caused by possibility of formation of H5O2 +-complexes which are located mainly on microcrystals surfaces and characterized by lower energy of proton transfer in comparison with H3O+-complexes which occur in bulk of APO with cubic structure. Explanation of the nature of wide band in Raman scattering spectra is proposed. Model calculations and theoretical curves are presented.
Modelling Flexible Manipulators With Motors at the Joints

A computationally efficient recursive model of a flexible manipulator with motors at the joints is described in this paper. The model adopts a mixed Eulerian and Lagrangian formulation of the equations of a flexible body and exploits the chained structure of the equations for a serial manipulator. The dynamic effects of the motors at the joints, including gyroscopic terms, are fully taken into account. Symbolic manipulation is used in a newly developed package, whose performance in detailed reproduction of the dynamic effects due to the interplay between the motors and the flexible links is assessed through simulation. A comparison between the complete model and a simplified one, where the motors are considered as simple inertias rotating around their own axis, has been carried out, using both a time domain analysis and a frequency domain analysis, in order to show the relevance of gyroscopic effects in modelling flexible robots.
The effect of magnet size on the levitation force and attractive force of single-domain YBCO bulk superconductors

The levitation forces between a single-domain YBCO bulk and several magnets of different sizes have been measured at 77 K to investigate the effect of the magnet size on the levitation force. It is found that the levitation force reaches a largest (peak) value when the size of the magnet approaches that of the superconductor when the other conditions are fixed. The absolute maximum attractive force (in the field-cooled state) increases with the increasing of the magnet size, and is saturated when the magnet size approaches that of the superconductor. The maximum attractive force in the field-cooled (FC) state is much higher than that of the maximum attractive force in the zero field-cooled (ZFC) state. The results indicate that the effects of magnetic field distribution on the levitation force have to be considered during the designing and manufacturing of superconducting devices.
Viscous irrotational analysis of the deformation and break-up time of a bubble or drop in uniaxial straining flow*

Abstract The nonlinear deformation and break-up of a bubble or drop immersed in a uniaxial extensional flow of an incompressible viscous fluid is analysed by means of viscous potential flow. In this approximation, the flow field is irrotational and viscosity enters through the balance of normal stresses at the interface. The governing equations are solved numerically to track the motion of the interface by coupling a boundary-element method with a time-integration routine. When break-up occurs, the break-up time computed here is compared with results obtained elsewhere from numerical simulations of the Navier–Stokes equations (Revuelta, Rodríguez-Rodríguez & Martínez-Bazán J. Fluid Mech., vol. 551, 2006, p. 175), which thus keeps vorticity in the analysis, for several combinations of the relevant dimensionless parameters of the problem. For the bubble, for Weber numbers $3\leqslant \mathit{We}\leqslant 6$, predictions from viscous potential flow shows good agreement with the results from the Navier–Stokes equations for the bubble break-up time, whereas for larger $\mathit{We}$, the former underpredicts the results given by the latter. When viscosity is included, larger break-up times are predicted with respect to the inviscid case for the same $\mathit{We}$. For the drop, and considering moderate Reynolds numbers, $\mathit{Re}$, increasing the viscous effects of the irrotational motion produces large, elongated drops that take longer to break up in comparison with results for inviscid fluids. For larger $\mathit{Re}$, it comes as a surprise that break-up times smaller than the inviscid limit are obtained. Unfortunately, results from numerical analyses of the incompressible, unsteady Navier–Stokes equations for the case of a drop have not been presented in the literature, to the best of the authors’ knowledge; hence, comparison with the viscous irrotational analysis is not possible.
Precipitation Estimates from MSG SEVIRI Daytime, Nighttime, and Twilight Data with Random Forests

AbstractA new rainfall retrieval technique for determining rainfall rates in a continuous manner (day, twilight, and night) resulting in a 24-h estimation applicable to midlatitudes is presented. The approach is based on satellite-derived information on cloud-top height, cloud-top temperature, cloud phase, and cloud water path retrieved from Meteosat Second Generation (MSG) Spinning Enhanced Visible and Infrared Imager (SEVIRI) data and uses the random forests (RF) machine-learning algorithm. The technique is realized in three steps: (i) precipitating cloud areas are identified, (ii) the areas are separated into convective and advective-stratiform precipitating areas, and (iii) rainfall rates are assigned separately to the convective and advective-stratiform precipitating areas. Validation studies were carried out for each individual step as well as for the overall procedure using collocated ground-based radar data. Regarding each individual step, the models for rain area and convective precipitation dete.
Impact of carbon monoxide on neural activation during a reaction time task

Individuals are routinely exposed to low-level carbon monoxide (CO), by factors such as ambient pollution and tobacco smoking. It is known that inhalation of high levels of CO have a detrimental impact on cognitive function. This study sought to investigate the impact of low-level CO exposure on central nervous system cognitive processing speed, using Blood Oxygen Level Dependant (BOLD) functional Magnetic Resonance Imaging (fMRI). The effects of low-level CO (raised up to 6ppm in exhaled air) on reaction times and fMRI activation maps were measured in healthy non-smoking participants. Participants received BOLD fMRI scans on two separate occasions (air and CO intervention days) and were scanned during the performance of a simple reaction time task. Results showed mean activation in cerebellum and motor cortex for all conditions. A significant reduction in BOLD response in the right temporal gyrus was found following CO inhalation, compared to the air control. Reaction times were significantly slower after CO exposure on the CO experimental day, but did not significantly change on the air control experimental day. This suggest that even low-level CO may impact both behavioural and BOLD fMRI outcomes.
Hydromagnetic gradient waves in the ionosphere

Hydromagnetic gradient (HMG) waves are a magnetohydrodynamic analog of Rossby waves. It is shown here that conditions for their existence are approximately satisfied in the so-called dynamo layer of the atmosphere. As a result, it appears plausible to assume the existence of HMG waves as traveling perturbations of the Sq current system. Corresponding micropulsations of the earth's magnetic field are estimated and may be measurable.
Regulation of Ebola GP conformation and membrane binding by the chemical environment of the late endosome

Interaction between the Ebola virus envelope glycoprotein (GP) and the endosomal membrane is an essential step during virus entry into the cell. Acidic pH and Ca2+ have been implicated in mediating the GP-membrane interaction. However, the molecular mechanism by which these environmental factors regulate the conformational changes that enable engagement of GP with the target membrane is unknown. Here, we apply fluorescence correlation spectroscopy (FCS) and single-molecule Förster resonance energy transfer (smFRET) imaging to elucidate how the acidic pH, Ca2+ and anionic phospholipids in the late endosome promote GP-membrane interaction, thereby facilitating virus entry. We find that bis(monoacylglycero)phosphate (BMP), which is specific to the late endosome, is especially critical in determining the Ca2+-dependence of the GP-membrane interaction. Molecular dynamics (MD) simulations suggested residues in GP that sense pH and induce conformational changes that make the fusion loop available for insertion into the membrane. We similarly confirm residues in the fusion loop that mediate GP’s interaction with Ca2+, which likely promotes local conformational changes in the fusion loop and mediates electrostatic interactions with the anionic phospholipids. Collectively, our results provide a mechanistic understanding of how the environment of the late endosome regulates the timing and efficiency of virus entry. Author Summary Ebola virus causes disease in humans with high fatality. A better understanding of how Ebola virus enters cells is critical to inform the development of novel therapeutic and preventative measures. The viral glycoprotein present on the surface of the virus mediates attachment to cells and subsequent entry through a poorly understood mechanism involving fusion of viral and cellular membranes. Here, we employ computational and experimental biophysical techniques to understand how the Ebola glycoprotein senses chemical cues in its environment, such as pH, calcium ions, and specific lipid species to ensure that entry occurs at the right time and place. Our results specify elements of the glycoprotein that control its structure under changing physiological environments.
Nitrogen-limitation independent control of glnA (glutamine synthetase) expression in Escherichia coli by urea, several amino acids, and post-transcriptional regulation

The expression of glnA (ammonia-assimilating glutamine synthetase) is high for uropathogenic E. coli grown in urine. Because glnA is part of an operon that codes for regulators of the nitrogen-regulated (Ntr) response, high glnA expression has been interpreted to suggest nitrogen limitation, which is unexpected because of the high urinary ammonia concentration and the extremely rapid bacterial growth. We present evidence that glnA expression does not result from nitrogen limitation. First, in the presence of ammonia, urea induced expression of glnA from the cAMP receptor protein (Crp)- dependent glnAp1 promoter, which circumvents control from the nitrogen-regulated glnAp2 promoter. This urea effect on glnA expression has not been previously described. Second, the most abundant amino acids in urine inhibited GS activity, based on reversal of the inhibition by glutamate and glutamine, and increased glnA expression. The relevance of these inhibitory amino acids in natural environments has not been previously demonstrated. Third, neither urea nor the inhibitory amino acids induced other Ntr genes, i.e., high glnA expression can be independent of other Ntr genes. Finally, the urea-dependent induction did not result in GlnA synthesis because of a previously undescribed translational control. We conclude that glnA expression in urea-containing environments does not imply growth rate-limiting nitrogen restriction and is consistent with rapid growth of uropathogenic E. coli. Significance Urinary tract infections (UTIs), often caused by E. coli, frequently become resistant to antibiotic treatment. Expressed metabolic genes during an infection could guide development of urgently-needed alternate or adjunct therapies. glnA (glutamine synthetase) is expressed during growth in urine, which implies growth-restricting nitrogen limitation. We show that glnA expression results from urinary amino acids that inhibit GlnA activity and urea, but not from nitrogen limitation. Urinary components will vary greatly between individuals which suggests corresponding variations in glnA expression. GlnA may be a metabolic vulnerability during UTIs, which may depend on a variable urinary composition. glnA expression may be important in a complex host-pathogen interaction, but may not be a good therapeutic target.
Hierarchical Deviant Processing in Auditory Cortex of Awake Mice

Detecting patterns, and noticing unexpected pattern changes, in the environment is a vital aspect of sensory processing. Adaptation and prediction error responses are two components of neural processing related to these tasks, and previous studies in the auditory system in rodents show that these two components are partially dissociable in terms of the topography and latency of neural responses to sensory deviants. However, many previous studies have focused on repetitions of single stimuli, such as pure tones, which have limited ecological validity. In this study, we tested whether the auditory cortical activity shows adaptation to repetition of more complex sound patterns (bisyllabic pairs). Specifically, we compared neural responses to violations of sequences based on single stimulus probability only, against responses to more complex violations based on stimulus order. We employed an auditory oddball paradigm and monitored the auditory cortex (ACtx) activity of awake mice (N=8) using wide-field calcium imaging. We found that cortical responses were sensitive both to single stimulus probabilities and to more global stimulus patterns, as mismatch signals were elicited following both substitution deviants and transposition deviants. Notably, A2 area elicited larger mismatch signaling to those deviants than primary ACtx (A1), which suggests a hierarchical gradient of prediction error signaling in the auditory cortex. Such a hierarchical gradient was observed for late but not early peaks of calcium transients to deviants, suggesting that the late part of the deviant response may reflect prediction error signaling in response to more complex sensory pattern violations.
Trial-history biases in evidence accumulation can give rise to apparent lapses

Trial history biases and lapses are two of the most common suboptimalities observed during perceptual decision-making. These suboptimalities are routinely assumed to arise from distinct processes. However, several hints in the literature suggest that they covary in their prevalence and that their proposed neural substrates overlap – what could underlie these links? Here we demonstrate that history biases and apparent lapses can both arise from a common cognitive process that is normative under misbeliefs about non-stationarity in the world. This corresponds to an accumulation- to-bound model with history-dependent updates to the initial state of the accumulator. We test our model’s predictions about the relative prevalence of history biases and lapses, and show that they are robustly borne out in two distinct rat decision-making datasets, including data from a novel reaction time task. Our model improves the ability to precisely predict decision-making dynamics within and across trials, by positing a process through which agents can generate quasi-stochastic choices.
An investigation of high-wavenumber temperature and velocity spectra in air

Turbulent temperature and velocity fluctuations in air were measured at a height of 4 m over a tidal mud flat. Particular attention was focused on the high-wavenumber, small-scale region of the spectra of these fluctuations. The measurements of the velocity fluctuations were made with a constant-temperature hot-wire anemometer; the hot wire consisted of a platinum wire 5 μm in diameter and approximately 1 mm in length. Temperature fluctuations were measured with a platinum resistance thermometer which consisted of a platinum wire 0·25 μm in diameter and about 0·30 mm in length. The velocity spectra results agree well with the classical results of Grant, Stewart & Moilliet (1962) and Pond, Stewart & Burling (1963). In addition, they extend the velocity spectrum in air to slightly higher wavenumbers. The one-dimensional Kolmogorov constant K’ estimated from these data was 0·51. The temperature spectra clearly show the shape of the one-dimensional temperature spectrum in air beyond the $-\frac{5}{3}$ region. In air temperature and velocity spectra are very similar. The value of the scalar constant K’0, which appears in the scalar $-\frac{5}{3}$ law, computed from these data was 0·81. Direct measurement was made of all parameters that enter into the calculation of it.
Functional characterization of the language network of polyglots and hyperpolyglots with precision fMRI

How do polyglots—individuals who speak five or more languages—process their languages, and what can this population tell us about the language system? Using fMRI, we identified the language network in each of 34 polyglots (including 16 hyperpolyglots with knowledge of 10+ languages) and examined its response to the native language, non-native languages of varying proficiency, and unfamiliar languages. All language conditions engaged all areas of the language network relative to a control condition. Languages that participants rated as higher-proficiency elicited stronger responses, except for the native language, which elicited a similar or lower response than a non-native language of similar proficiency. Furthermore, unfamiliar languages that were typologically related to the participants’ high-to-moderate-proficiency languages elicited a stronger response than unfamiliar unrelated languages. The results suggest that the language network’s response magnitude scales with the degree of engagement of linguistic computations (e.g., related to lexical access and syntactic-structure building). We also replicated a prior finding of weaker responses to native language in polyglots than non-polyglot bilinguals. These results contribute to our understanding of how multiple languages co-exist within a single brain and provide new evidence that the language network responds more strongly to stimuli that more fully engage linguistic computations.
Learning to predict future locations with internally generated theta sequences

Representing past, present and future locations is key for spatial navigation. Indeed, within each cycle of the theta oscillation, the population of hippocampal place cells appears to represent trajectories starting behind the current position of the animal and sweeping ahead of it. In particular, we reported recently that the position represented by CA1 place cells at a given theta phase corresponds to the location where animals were or will be located at a fixed time interval into the past or future assuming the animal ran at its typical, not the current, speed through that part of the environment. This coding scheme leads to longer theta trajectories, larger place fields and shallower phase precession in areas where animals typically run faster. Here we present a mechanistic computational model that accounts for these experimental observations. The model consists of a continuous attractor network with short-term synaptic facilitation and depression that internally generates theta sequences that advance at a fixed pace. Spatial locations are then mapped onto the active units via modified Hebbian plasticity. As a result, neighboring units become associated with spatial locations further apart where animals run faster, reproducing our earlier experimental results. The model also accounts for the higher density of place fields generally observed where animals slow down, such as around rewards. Furthermore, our modeling results reveal that an artifact of the decoding analysis might be partly responsible for the observation that theta trajectories start behind the animal’s current position. Overall, our results shed light on how the hippocampal code might arise from the interplay between behavior, sensory input and predefined network dynamics.