How many dimensions are required to find an adversarial example?

Past work exploring adversarial vulnerability have focused on situations where an adversary can perturb all dimensions of model input. On the other hand, a range of recent works consider the case where either (i) an adversary can perturb a limited number of input parameters or (ii) a subset of modalities in a multimodal problem. In both of these cases, adversarial examples are effectively constrained to a subspace $V$ in the ambient input space $\mathcal{X}$. Motivated by this, in this work we investigate how adversarial vulnerability depends on $\dim(V)$. In particular, we show that the adversarial success of standard PGD attacks with $\ell^p$ norm constraints behaves like a monotonically increasing function of $\epsilon (\frac{\dim(V)}{\dim \mathcal{X}})^{\frac{1}{q}}$ where $\epsilon$ is the perturbation budget and $\frac{1}{p} + \frac{1}{q} =1$, provided $p > 1$ (the case $p=1$ presents additional subtleties which we analyze in some detail). This functional form can be easily derived from a simple toy linear model, and as such our results land further credence to arguments that adversarial examples are endemic to locally linear models on high dimensional spaces.Comment: Comments welcome! V2: minor edits for clarit

Convolutional networks inherit frequency sensitivity from image statistics

It is widely acknowledged that trained convolutional neural networks (CNNs) have different levels of sensitivity to signals of different frequency. In particular, a number of empirical studies have documented CNNs sensitivity to low-frequency signals. In this work we show with theory and experiments that this observed sensitivity is a consequence of the frequency distribution of natural images, which is known to have most of its power concentrated in low-to-mid frequencies. Our theoretical analysis relies on representations of the layers of a CNN in frequency space, an idea that has previously been used to accelerate computations and study implicit bias of network training algorithms, but to the best of our knowledge has not been applied in the domain of model robustness.Comment: Comments welcome

The Seventeenth Data Release of the Sloan Digital Sky Surveys: Complete Release of MaNGA, MaStar and APOGEE-2 Data

This paper documents the seventeenth data release (DR17) from the Sloan Digital Sky Surveys; the fifth and final release from the fourth phase (SDSS-IV). DR17 contains the complete release of the Mapping Nearby Galaxies at Apache Point Observatory (MaNGA) survey, which reached its goal of surveying over 10,000 nearby galaxies. The complete release of the MaNGA Stellar Library (MaStar) accompanies this data, providing observations of almost 30,000 stars through the MaNGA instrument during bright time. DR17 also contains the complete release of the Apache Point Observatory Galactic Evolution Experiment 2 (APOGEE-2) survey which publicly releases infra-red spectra of over 650,000 stars. The main sample from the Extended Baryon Oscillation Spectroscopic Survey (eBOSS), as well as the sub-survey Time Domain Spectroscopic Survey (TDSS) data were fully released in DR16. New single-fiber optical spectroscopy released in DR17 is from the SPectroscipic IDentification of ERosita Survey (SPIDERS) sub-survey and the eBOSS-RM program. Along with the primary data sets, DR17 includes 25 new or updated Value Added Catalogs (VACs). This paper concludes the release of SDSS-IV survey data. SDSS continues into its fifth phase with observations already underway for the Milky Way Mapper (MWM), Local Volume Mapper (LVM) and Black Hole Mapper (BHM) surveys

Stratification of biological therapies by pathobiology in biologic-naive patients with rheumatoid arthritis (STRAP and STRAP-EU): two parallel, open-label, biopsy-driven, randomised trials

Background Despite highly effective targeted therapies for rheumatoid arthritis, about 40% of patients respond poorly, and predictive biomarkers for treatment choices are lacking. We did a biopsy-driven trial to compare the response to rituximab, etanercept, and tocilizumab in biologic-naive patients with rheumatoid arthritis stratified for synovial B cell status. Methods STRAP and STRAP-EU were two parallel, open-label, biopsy-driven, stratified, randomised, phase 3 trials done across 26 university centres in the UK and Europe. Biologic-naive patients aged 18 years or older with rheumatoid arthritis based on American College of Rheumatology (ACR)–European League Against Rheumatism classification criteria and an inadequate response to conventional synthetic disease-modifying antirheumatic drugs (DMARDs) were included. Following ultrasound-guided synovial biopsy, patients were classified as B cell poor or B cell rich according to synovial B cell signatures and randomly assigned (1:1:1) to intravenous rituximab (1000 mg at week 0 and week 2), subcutaneous tocilizumab (162 mg per week), or subcutaneous etanercept (50 mg per week). The primary outcome was the 16-week ACR20 response in the B cell-poor, intention-to-treat population (defined as all randomly assigned patients), with data pooled from the two trials, comparing etanercept and tocilizumab (grouped) versus rituximab. Safety was assessed in all patients who received at least one dose of study drug. These trials are registered with the EU Clinical Trials Register, 2014-003529-16 (STRAP) and 2017-004079-30 (STRAP-EU). Findings Between June 8, 2015, and July 4, 2019, 226 patients were randomly assigned to etanercept (n=73), tocilizumab (n=74), and rituximab (n=79). Three patients (one in each group) were excluded after randomisation because they received parenteral steroids in the 4 weeks before recruitment. 168 (75%) of 223 patients in the intention-to-treat population were women and 170 (76%) were White. In the B cell-poor population, ACR20 response at 16 weeks (primary endpoint) showed no significant differences between etanercept and tocilizumab grouped together and rituximab (46 [60%] of 77 patients vs 26 [59%] of 44; odds ratio 1·02 [95% CI 0·47–2·17], p=0·97). No differences were observed for adverse events, including serious adverse events, which occurred in six (6%) of 102 patients in the rituximab group, nine (6%) of 108 patients in the etanercept group, and three (4%) of 73 patients in the tocilizumab group (p=0·53). Interpretation In this biologic-naive population of patients with rheumatoid arthrtitis, the dichotomic classification into synovial B cell poor versus rich did not predict treatment response to B cell depletion with rituximab compared with alternative treatment strategies. However, the lack of response to rituximab in patients with a pauci-immune pathotype and the higher risk of structural damage progression in B cell-rich patients treated with rituximab warrant further investigations into the ability of synovial tissue analyses to inform disease pathogenesis and treatment response

Effect of propofol and sevoflurane on coughing in smokers and non-smokers awakening from general anaesthesia at the end of a cervical spine surgery.

BACKGROUND: Coughing during emergence from general anaesthesia may be detrimental, particularly after cervical spine surgery. We compared the effect of propofol or sevoflurane anaesthesia on the incidence and severity of coughing during recovery in patients undergoing cervical spine surgery via an anterior approach. As a secondary aim, we also evaluated the influences of smoking and estimated residual anaesthetic agent concentrations on coughing. METHODS: Thirty-four patients were enrolled in a randomized prospective, double-blind study to receive either propofol (PPF) or sevoflurane (SEVO) for maintenance of anaesthesia. The decision to perform tracheal extubation was based on specified criteria, including resumption of spontaneous respiration and consciousness. During emergence from anaesthesia and extubation, coughing was observed and graded at predefined times. RESULTS: The incidence of severe coughing was higher in the SEVO group than in the PPF group (59% and 6%, respectively), and also in smokers than in non-smokers (50% and 17%, respectively). The peak incidence of coughing was at tracheal extubation. The probability of coughing was influenced by the estimated residual concentration of anaesthetic agents at extubation, except for smokers in the SEVO group who were at the highest risk of coughing. CONCLUSIONS: The incidence of coughing after cervical spine surgery when tracheal extubation is performed according to clinical criteria is lower after propofol anaesthesia compared with sevoflurane anaesthesia. Smokers are at increased risk of coughing, independently of the type of anaesthesia maintenance. Higher residual concentrations of anaesthetic agents decrease the probability of coughing, except for smokers anaesthetized with sevoflurane

Understanding and addressing changing administrative workload in primary care in Canada: protocol for a mixed-method study

Introduction Many Canadians struggle to access the primary care they need while at the same time primary care providers report record levels of stress and overwork. There is an urgent need to understand factors contributing to the gap between a growing per-capita supply of primary care providers and declines in the availability of primary care services. The assumption of responsibility by primary care teams for services previously delivered on an in-patient basis, along with a rise in administrative responsibilities may be factors influencing reduced access to care.Methods and analysis In this mixed-methods study, our first objective is to determine how the volume of services requiring primary care coordination has changed over time in the Canadian provinces of Nova Scotia and New Brunswick. We will collect quantitative administrative data to investigate how services have shifted in ways that may impact administrative workload in primary care. Our second objective is to use qualitative interviews with family physicians, nurse practitioners and administrative team members providing primary care to understand how administrative workload has changed over time. We will then identify priority issues and practical response strategies using two deliberative dialogue events convened with primary care providers, clinical and system leaders, and policy-makers.We will analyse changes in service use data between 2001/2002 and 2021/2022 using annual total counts, rates per capita, rates per primary care provider and per primary care service. We will conduct reflexive thematic analysis to develop themes and to compare and contrast participant responses reflecting differences across disciplines, payment and practice models, and practice settings. Areas of concern and potential solutions raised during interviews will inform deliberative dialogue events.Ethics and dissemination We received research ethics approval from Nova Scotia Health (#1028815). Knowledge translation will occur through dialogue events, academic papers and presentations at national and international conferences