Miracle-dz/UniFAR-FTUs huggingface dataset:
Boosted optimal weighted least-squares

This paper is concerned with the approximation of a function $u$ in a given approximation space $V_m$ of dimension $m$ from evaluations of the function at $n$ suitably chosen points. The aim is to construct an approximation of $u$ in $V_m$ which yields an error close to the best approximation error in $V_m$ and using as few evaluations as possible. Classical least-squares regression, which defines a projection in $V_m$ from $n$ random points, usually requires a large $n$ to guarantee a stable approximation and an error close to the best approximation error. This is a major drawback for applications where $u$ is expensive to evaluate. One remedy is to use a weighted least squares projection using $n$ samples drawn from a properly selected distribution. In this paper, we introduce a boosted weighted least-squares method which allows to ensure almost surely the stability of the weighted least squares projection with a sample size close to the interpolation regime $n=m$. It consists in sampling according to a measure associated with the optimization of a stability criterion over a collection of independent $n$-samples, and resampling according to this measure until a stability condition is satisfied. A greedy method is then proposed to remove points from the obtained sample. Quasi-optimality properties are obtained for the weighted least-squares projection, with or without the greedy procedure. The proposed method is validated on numerical examples and compared to state-of-the-art interpolation and weighted least squares methods.
Towards Causal VQA: Revealing and Reducing Spurious Correlations by Invariant and Covariant Semantic Editing

Despite significant success in Visual Question Answering (VQA), VQA models have been shown to be notoriously brittle to linguistic variations in the questions. Due to deficiencies in models and datasets, today’s models often rely on correlations rather than predictions that are causal w.r. t. data. In this paper, we propose a novel way to analyze and measure the robustness of the state of the art models w.r. t semantic visual variations as well as propose ways to make models more robust against spurious correlations. Our method performs automated semantic image manipulations and tests for consistency in model predictions to quantify the model robustness as well as generate synthetic data to counter these problems. We perform our analysis on three diverse, state of the art VQA models and diverse question types with a particular focus on challenging counting questions. In addition, we show that models can be made significantly more robust against inconsistent predictions using our edited data. Finally, we show that results also translate to real-world error cases of state of the art models, which results in improved overall performance
Localizability in $\kappa$-Minkowski Spacetime

Using the methods of ordinary quantum mechanics we study $\kappa$-Minkowski space as a quantum space described by noncommuting self-adjoint operators, following and enlarging arXiv:1811.08409. We see how the role of Fourier transforms is played in this case by Mellin transforms. We briefly discuss the role of transformations and observers.
Properties of simulated galaxies and supermassive black holes in cosmic voids

Cosmic voids, the underdense regions of the cosmic web, are widely used to constrain cosmology. Voids contain few, isolated galaxies, presumably expected to be less evolved and preserving memory of the pristine Universe. We use the cosmological hydrodynamical simulation Horizon-AGN coupled to the void finder vide to investigate properties of galaxies in voids at z = 0. We find that, closer to void centres, low-mass galaxies are more common than their massive counterparts. At a fixed dark matter halo mass, they have smaller stellar masses than in denser regions. The star formation rate of void galaxies diminishes when approaching void centres, but their specific star formation rate slightly increases, suggesting that void galaxies form stars more efficiently with respect to their stellar mass. We find that this cannot only be attributed to the prevalence of low-mass galaxies. The inner region of voids also predominantly hosts low-mass black holes (BHs). However, the BH mass-to-galaxy mass ratios resemble those of the whole simulation at z = 0. Our results suggest that even if the growth channels in cosmic voids are different from those in denser environments, voids grow their galaxies and BHs in a similar way. While a large fraction of the BHs have low Eddington ratios, we find that $\text{$\sim$} 20{{\ \rm per\ cent}}$ could be observed as active galactic nuclei with $\log _{10} L_{\rm 2\! -\! 10 \, keV}=41.5\! -\! 42.5 \, \rm erg\, s^{-1}$. These results pave the way to future work with larger next-generation hydro-simulations, aiming to confirm our findings and prepare the application on data from upcoming large surveys such as Prime Focus Spectrograph, Euclid, and Wide Field Infrared Survey Telescope.
Genuine multipartite correlations distribution in the criticality of the Lipkin-Meshkov-Glick model

Correlations play a key role in critical phenomena. Quantities such as the entanglement entropy, for instance, provide key insights into the mechanisms underlying quantum criticality. Almost all of our present knowledge, however, is restricted to bipartite correlations. Some questions still remain unanswered, such as: What parcel of the total correlations are genuinely $k$-partite? With the goal of shedding light on this difficult question, in this paper we put forth a detailed study of the behavior of genuine multipartite correlations (GMC) of arbitrary orders in the Lipkin-Meshkov-Glick model. We find that GMC of all orders serve to signal the second order quantum phase transition presented in the model. Applying finite-size scaling methods, we also find the critical exponents for some orders of correlations.
On Jones' connections between subfactors, conformal field theory, Thompson's groups and knots

Surprisingly Richard Thompson's groups have recently appeared in Jones' subfactor theory. Vaughan Jones is famous for linking theories that are a priori completely disconnected; for instance, his celebrated polynomial for links emanating from subfactor theory. This note is about a new beautiful story in mathematics which results from a fortunate accident in the land of quantum field theory.
Mixing Time Estimation in Ergodic Markov Chains from a Single Trajectory with Contraction Methods

The mixing time $t_{\mathsf{mix}}$ of an ergodic Markov chain measures the rate of convergence towards its stationary distribution $\boldsymbol{\pi}$. We consider the problem of estimating $t_{\mathsf{mix}}$ from one single trajectory of $m$ observations $(X_1, . . . , X_m)$, in the case where the transition kernel $\boldsymbol{M}$ is unknown, a research program started by Hsu et al. [2015]. The community has so far focused primarily on leveraging spectral methods to estimate the relaxation time $t_{\mathsf{rel}}$ of a reversible Markov chain as a proxy for $t_{\mathsf{mix}}$. Although these techniques have recently been extended to tackle non-reversible chains, this general setting remains much less understood. Our new approach based on contraction methods is the first that aims at directly estimating $t_{\mathsf{mix}}$ up to multiplicative small universal constants instead of $t_{\mathsf{rel}}$. It does so by introducing a generalized version of Dobrushin's contraction coefficient $\kappa_{\mathsf{gen}}$, which is shown to control the mixing time regardless of reversibility. We subsequently design fully data-dependent high confidence intervals around $\kappa_{\mathsf{gen}}$ that generally yield better convergence guarantees and are more practical than state-of-the-art.
Boundary Blow-Up Analysis of Gradient Estimates for Lamé Systems in the Presence of m-Convex Hard Inclusions

In high-contrast elastic composites, it is vitally important to investigate the stress concentration from an engineering point of view. The purpose of this paper is to show that the blowup rate of the stress depends not only on the shape of the inclusions, but also on the given boundary data, when hard inclusions are close to matrix boundary. First, when the boundary of inclusion is partially relatively parallel to that of matrix, we establish the gradient estimates for Lam\'{e} systems with partially infinite coefficients and find that they are bounded for some boundary data $\varphi$ while some $\varphi$ will increase the blow-up rate. In order to identify such novel blowup phenomenon, we further consider the general $m$-convex inclusion cases and uncover the dependence of blow-up rate on the inclusion's convexity $m$ and the boundary data's order of growth $k$ in all dimensions. In particular, the sharpness of these blow-up rates is also presented for some prescribed boundary data.
Stochastic Modeling of Beam Management in mmWave Vehicular Networks

Mobility management is a major challenge for millimeter-wave (mmWave) cellular networks. In particular, directional beamforming in mmWave devices renders high-speed mobility support very complex. This complexity, however, is not limited to system design but also the performance estimation and evaluation. Hence, some have turned their attention to stochastic modeling of mmWave vehicular communication to derive closed-form expressions that can characterize the coverage and rate behavior of the network. In this article, we model and analyze the beam management for mmWave vehicular networks. To the best of our knowledge, this is the first work that goes beyond coverage and rate analysis. Specifically, we focus on a multi-lane divided highway scenario in which base stations and vehicles are present on both sides of the highway. In addition to providing analytical expressions for the average number of beam switching and handover events, we provide design insights for the operators to fine-tune their network through more informed choice of system parameters, including the number of resources dedicated to channel feedback and beam alignment operations.
UAV-to-UAV Communications in Cellular Networks

We consider a cellular network deployment where UAV-to-UAV (U2U) transmit-receive pairs share the same spectrum with the uplink (UL) of cellular ground users (GUEs). For this setup, we focus on analyzing and comparing the performance of two spectrum sharing mechanisms: (i) underlay, where the same time-frequency resources may be accessed by both UAVs and GUEs, resulting in mutual interference, and (ii) overlay, where the available resources are divided into orthogonal portions for U2U and GUE communications. We evaluate the coverage probability and rate of both link types and their interplay to identify the best spectrum sharing strategy. We do so through an analytical framework that embraces realistic height-dependent channel models, antenna patterns, and practical power control mechanisms. For the underlay, we find that although the presence of U2U direct communications may worsen the uplink performance of GUEs, such effect is limited as base stations receive the power-constrained UAV signals through their antenna sidelobes. In spite of this, our results lead us to conclude that in urban scenarios with a large number of UAV pairs, adopting an overlay spectrum sharing seems the most suitable approach for maintaining a minimum guaranteed rate for UAVs and a high GUE UL performance.
Global constraints preserving SAV schemes for gradient flows

We develop several efficient numerical schemes which preserve exactly the global constraints for constrained gradient flows. Our schemes are based on the SAV approach combined with the Lagrangian multiplier approach. They are as efficient as the SAV schemes for unconstrained gradient flows, i.e., only require solving linear equations with constant coefficients at each time step plus an additional nonlinear algebraic system which can be solved at negligible cost, can be unconditionally energy stable, and preserve exactly the global constraints for constrained gradient flows. Ample numerical results for phase-field vesicle membrane and optimal partition models are presented to validate the effectiveness and accuracy of the proposed numerical schemes.
Public Innovation and Changes in Communal Access to Timber in the Northern Bolivian Amazon

SUMMARY The paper assesses the effects of public innovation initiated by demands from communities in the northern Bolivian Amazon to revise forest regulations and policies. Bolivia enacted wide-reaching land and forest reforms in the mid-1990s, but these reforms were insufficient to tackle competing claims on forests and exclusion of local forest users from benefiting from timber production. Pressures by forest communities resulted in significant adjustments in regulations and policies, and the main driver was social pressure from communities as well as their representatives. The adjustments have allowed communal local practices, which were previously illegal, to become legal. They have allowed communities access to timber markets, improve incomes, and enhanced compliance with timber regulations.
The Drivers and Evolution of Competing Forest Certification Schemes in the Chilean Forestry Industry

SUMMARY Forest certification was introduced to Chile twenty years ago, to promote sustainable forest management, address the degradation of natural forests, and ameliorate social issues associated with an economically-successful industrial plantation forestry industry. Adoption of certification in Chile offers an informative case study of competition between the two international schemes, FSC and the PEFC-endorsed CERTFOR. This qualitative study explores the reasons why forestry businesses in each of the plantation and native forestry sectors sought, promoted and maintained certification under one or both schemes. Results show that their motivations to adopt and maintain a particular certification scheme depend not only on market access or social licence to operate but also on contextual factors, including the structure of the forest industry and historical land tenure disputes. The current situation reflects the history of certification: notwithstanding that the schemes have converged, the FSC still dominates the SFM discourse, but Chile's forestry industry has maintained CERTFOR for political reasons.
Comparison of norepinephrine and phenylephrine boluses for the treatment of hypotension during spinal anaesthesia for caesarean section – A randomised controlled trial

Background and Aims: Hypotension following spinal anaesthesia for caesarean section is common in spite of adequate fluid loading. Phenylephrine is the recommended drug to treat spinal hypotension during caesarean section. Recently, norepinephrine boluses are being suggested as an alternative to phenylephrine boluses. The aim of our study was to compare the effectiveness of bolus doses of norepinephrine with phenylephrine to treat spinal hypotension during caesarean section. Methods: Fifty patients undergoing elective caesarean section under spinal anaesthesia were randomly assigned into two groups. Group P patients received phenylephrine 50 μg as an intravenous bolus and group N received 4 μg of norepinephrine as intravenous bolus to treat spinal hypotension. The primary objective of our study was to compare the number of bolus doses of norepinephrine or phenylephrine required to treat spinal hypotension. The secondary objectives were to compare the incidence of bradycardia, hypertension, nausea and vomiting in mother and foetal outcomes. Results: The number of boluses of vasopressors required to treat hypotension was significantly lower in group N (1.40 ± 0.577 vs. 2.28 ± 1.061, P = 0.001). The frequency of bradycardia was high in group P, but this difference was not statistically significant (4%vs. 20%, P = 0.192). Maternal complications such as nausea and vomiting and shivering were comparable between the groups. The foetal parameters were also comparable between the two groups. Conclusion: Intermittent boluses of norepinephrine are effective in the management of spinal-induced hypotension during caesarean section. The neonatal outcomes were similar in both the groups. Norepinephrine boluses can be considered as an alternative to phenylephrine boluses.
Role of central venous oxygen saturation in prognostication of patients with severe sepsis and septic shock in emergency medical services

Introduction: All the components of early goal-directed therapy, especially central venous oxygen saturation (ScvO2) as one of the endpoints of resuscitation, may not have mortality benefit, more so after results of the Australasian Resuscitation of Sepsis Evaluation, A Randomized Trial of Protocol-Based Care for Early Septic Shock, and The Protocolised Management in Sepsis trials. However, extrapolating results from trials undertaken in the developed world may not be entirely appropriate. Materials and Methods: In this prospective observational study conducted in the emergency medical services, we aimed to find out the mean baseline ScvO2in a cohort of 200 patients presenting with severe sepsis/septic shock and its prognostic significance. The measurement of ScvO2was performed by sampling blood from the superior vena cava through the central venous catheter. Results: The mean age of patients was 46.70 ± 17.64 years. The mean ScvO2at baseline of the study cohort was 65.95 ± 20.70%. Based on initial ScvO2values, 104 (52%) patients had a lower ScvO2level, a priori classified as the hypoxic group. Sixty-five (32.5%) patients had an initial ScvO2level in between 70 and 89%, categorized as normoxic group, and the remaining 31 (15.5%) patients had high ScvO2, leveled as the hyperoxic group. Sixty-six (33%) patients had hospital mortality. Of 104 hypoxemic patients, 28 (26.9%) had hospital mortality. In this group, the mean ScvO2value in 28 nonsurvivors at baseline and after 6 h of resuscitation was 46.21 ±16.66% and 48.82 ±18.81%, respectively. Twenty-five (38.5%) patients had hospital mortality among 65 patients with baseline ScvO2value in the normoxic range. Hospital mortality figure stood at 13 (41.9%) patients in the hyperoxic group. Among patients in the hyperoxic group, the mean serum lactate value at baseline in nonsurvivors was 4.52 ± 2.95 mmol/L, significantly higher as compared to the mean value of 2.89 ± 1.55 mmol/L in survivors. The hyperoxia group had higher hospital mortality though it was not statistically significant. Conclusion: The mean baseline ScvO2was lower in our study cohort. In the hypoxic group, patients with hospital mortality had persistently lower ScvO2level during the first 6 h of resuscitation. Importantly, higher mortality in the hyperoxic group with high serum lactate emphasizes the point that ScvO2value should be analyzed along with serum lactate levels as complimentary resuscitation endpoints.
Effect of psychotic symptoms on cognitive impairment in patients with bipolar disorder

Background: A considerable proportion of patients with bipolar disorder (BD) have psychotic symptoms during the illness. This subset of BD due to its genetic susceptibility and family segregation has considerable overlap with schizophrenia. However, the extent to which BD patients with psychotic symptoms and without psychotic symptoms differ on neurocognitive functions is still not completely clear. Aim: The aim of this study was to examine the neurocognitive functions in BD patients with psychotic symptoms and BD without psychotic symptoms in comparison with healthy volunteers (HVs). Materials and Methods: Thirty patients with Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition BD (16 with psychotic symptoms) and thirty age- and sex-matched HVs were recruited in the study. Clinical severity was assessed using structured rating scales. The presence of psychotic symptoms was assessed using the Lifetime Dimensions of Psychosis Scale (LDPS). All patients underwent tests, namely continuous performance test, Stroop Word-Color interference test, and Wisconsin Card Sorting Test, to measure executive functions. Differences between groups were examined using analysis of covariance with age and sex as covariates. Results: There was a significant difference between groups on the performance of all the three tests, with patients performing poorer than HVs. While the HVs differed from both BD with psychotic symptoms and without psychotic symptoms, there was no difference between BD patients with and without psychotic symptoms. There was no significant correlation between LDPS score and scores on neurocognitive tests. Conclusion: The study findings, at least with respect to cognitive function, suggest that BD with psychotic symptoms may not be a categorically distinct subtype of BD. Cognitive functions need to be assessed in all patients with BD, regardless of psychotic symptoms, and remediation interventions need to be provided.
‘Safe anaesthesia care for all’ in India – Challenges

© 2019 Indian Journal of Anaesthesia | Published by Wolters Kluwer Medknow The provision of adequate surgical cover is a prerequisite to accomplishing local and global health goals. [1] A large section of people seeking surgical care cannot afford the financial burden of medical treatment. About 90% of patients in lowand lower-middle-income countries do not have access to primary surgical care. [2] Safe anaesthetic care is essential to ensure safe outcomes of surgery. Five billion people across the world have no access to safe anaesthetic care. In this issue of the journal, Law et al. spell out various issues and barriers in the path to achieve safe and accessible anaesthesia care. [3]
Prognostic Indicators of Oral Squamous Cell Carcinoma

Background: Oral squamous cell carcinoma (OSCC) is the sixth most common malignancy worldwide and is the major public health problem in the Indian subcontinent, where it ranks among the top three types of cancer in the country. Here, we aimed to analyze the clinical and tumor characteristics which impact the survival of OSCC patients. Methods: A retrospective analysis of clinical records of all patients who underwent treatment for OSCC at Kidwai Memorial Institute of Oncology, between January 2009 and January 2012 was analyzed. Age, gender, site of the primary lesion, tumor size (T), nodal status (N), stage of the disease, marginal status, and modality of treatment data were collected and analyzed. Results: Data of 147 patients with OSCC were included in the study and analyzed. Of the patients analyzed 61% were male, with 56% were <65 years, and 40% presented with buccal mucosa cancer followed by 30% with tongue cancer. Of all patients, 30% of them presented with Stage 1 and rest were Stage 2 and above. In our study, 40% underwent surgery only followed by regular follow-up and 60% needed surgery with postoperative adjuvant treatment based on the marginal status, the lymph node status, and T status of the disease. Conclusion: Our data suggest that age <65 years, female patients, alveolus lesion and tongue lesion and the early T Stage and N0 and negative margin had a significant positive impact on disease-free and overall survival of oral cancer patients.