EffectiveSan: Type and Memory Error Detection using Dynamically Typed C/C++

Low-level programming languages with weak/static type systems, such as C and C++, are vulnerable to errors relating to the misuse of memory at runtime, such as (sub-)object bounds overflows, (re)use-after-free, and type confusion. Such errors account for many security and other undefined behavior bugs for programs written in these languages. In this paper, we introduce the notion of dynamically typed C/C++, which aims to detect such errors by dynamically checking the "effective type" of each object before use at runtime. We also present an implementation of dynamically typed C/C++ in the form of the Effective Type Sanitizer (EffectiveSan). EffectiveSan enforces type and memory safety using a combination of low-fat pointers, type meta data and type/bounds check instrumentation. We evaluate EffectiveSan against the SPEC2006 benchmark suite and the Firefox web browser, and detect several new type and memory errors. We also show that EffectiveSan achieves high compatibility and reasonable overheads for the given error coverage. Finally, we highlight that EffectiveSan is one of only a few tools that can detect sub-object bounds errors, and uses a novel approach (dynamic type checking) to do so.Comment: To appear in the Proceedings of 39th ACM SIGPLAN Conference on Programming Language Design and Implementation (PLDI2018

Inelastic collapse of a randomly forced particle

We consider a randomly forced particle moving in a finite region, which rebounds inelastically with coefficient of restitution r on collision with the boundaries. We show that there is a transition at a critical value of r, r_c\equiv e^{-\pi/\sqrt{3}}, above which the dynamics is ergodic but beneath which the particle undergoes inelastic collapse, coming to rest after an infinite number of collisions in a finite time. The value of r_c is argued to be independent of the size of the region or the presence of a viscous damping term in the equation of motion.Comment: 4 pages, REVTEX, 2 EPS figures, uses multicol.sty and epsf.st

Engaging Stigmatised Communities in Australia with Digital Health Systems: Towards Data Justice in Public Health

Introduction: In 2018, following government policy changes to Australia’s national electronic health record system, ‘My Health Record’, consumer advocates—including organisations representing people living with HIV, people who use drugs and sex workers—raised concerns about privacy and data security. Responding to these controversies, this study explores the practical, ethical and political complexities of engaging stigmatised communities with digital health systems. Methods: We conducted 16 qualitative semi-structured interviews in 2020 with key informants representing communities who experience stigma, discrimination and marginalisation in Australia. These communities included people living with HIV, sex workers, people who inject drugs, gay and bisexual men and transgender and gender diverse people. We conducted a reflexive thematic analysis. Results: Key informants were sceptical of proposed benefits of electronic health records for their communities, and concerned about privacy risks and the potential for discrimination. Meaningful consultation, consent mechanisms and tackling structural stigma were raised as solutions for engaging communities. Conclusions: Although communities could benefit from being included in digital health systems, significant cultural, legal and social reforms from government were believed to be necessary to build trust in digital health systems. We argue that these forms of data justice are necessary for effective future systems. Policy Implications: Engaging stigmatised communities—including in relation to gender, sexuality, sex work, drug use, HIV—requires a commitment to data justice. The design and implementation of digital health systems requires investment in ongoing and meaningful consultation with communities and representative organisations

Annual Wormwood Leaf Inhibits the Adipogenesis of 3T3-L1 and Obesity in High-Fat Diet-Induced Obese Rats

Annual wormwood (AW) (Artemisia annua L.) has anti-malarial, anti-bacterial, anti-oxidant, anti-tumour, and anti-inflammatory activities. In the present study, we evaluated the effects of annual wormwood leaves (AWL) on adipocyte differentiation in 3T3-L1 cells and high-fat diet (HFD)-induced obese rats. 3T3-L1 adipocytes and HFD-induced obese rats were treated with AWL, and its effect on gene expression was analyzed using RT-PCR and Western blotting experiments. Treatment with AWL effectively prevented triglyceride accumulation during adipogenesis in a dose-dependent manner. Consistently, AWL suppressed the differentiation of 3T3-L1 preadipocytes into adipocytes through the downregulation of dexamethasone, 3-isobutyl-1- methylxanthine, and insulin (DMI)-induced serine/threonine kinase protein kinase B (PKB/Akt) activation and the expression of adipogenic genes, including the CCAAT/enhancer binding protein-alpha (C/EBPalpha) and peroximal proliferator-activated receptor-gamma (PPARgamma). Moreover, the expression of adipocyte fatty acid-binding protein 4 (aP2), which is a known PPARgamma-target gene, was downregulated by AWL treatment. Oral administration of AWL extracts significantly decreased the body weight gain, adipose tissue mass, adipocyte cell size, serum triglyceride (TG), and total cholesterol (TC) levels in HFD-induced obese rats. These results provide novel insight into the molecular mechanisms underlying the anti-obesity effects of AWL that are mediated by the downregulation of the expression of major adipogenic transcription factors, C/EBPalpha and PPARgamma and Akt signalling

The effects of nonlinear wave propagation on the stability of inertial cavitation

In the context of forecasting temperature and pressure fields in high-intensity focussed ultrasound, the accuracy of predictive models is critical for the safety and efficacy of treatment. In such fields inertial cavitation is often observed. Classically, estimations of cavitation thresholds have been based on the assumption that the incident wave at the surface of a bubble was the same as in the far-field, neglecting the effect of nonlinear wave propagation. By modelling the incident wave as a solution to Burgers' equation using weak shock theory, the effects of nonlinear wave propagation on inertial cavitation are investigated using both numerical and analytical techniques. From radius-time curves for a single bubble, it is observed that there is a reduction in the maximum size of a bubble undergoing inertial cavitation and that the inertial collapse occurs earlier in contrast with the classical case. Corresponding stability thresholds for a bubble whose initial radius is slightly below the critical Blake radius are calculated. Bifurcation diagrams and frequency-response curves are presented associated with the loss of stability. The consequences and physical implications of the results are discussed with respect to the classical results.Comment: 13 pages, 5 figures, submitted to J. Phys. Conf. Se

Investigation of CO, C2H6 and Aerosols in a Boreal Fire Plume Over Eastern Canada During BORTAS 2011 Using Ground- and Satellite-Based Observations and Model Simulations

We present the results of total column measurements of CO, C2H6 and fine-mode aerosol optical depth (AOD) during the Quantifying the impact of BOReal forest fires on Tropospheric oxidants over the Atlantic using Aircraft and Satellites (BORTAS-B) campaign over eastern Canada. Ground-based observations, using Fourier transform spectrometers (FTSs) and sun photometers, were carried out in July and August 2011. These measurements were taken in Halifax, Nova Scotia, which is an ideal location to monitor the outflow of boreal fires from North America, and also in Toronto, Ontario. Measurements of fine-mode AOD enhancements were highly correlated with enhancements in coincident trace gas (CO and C2H6) observations between 19 and 21 July 2011, which is typical for a smoke plume event. In this paper, we focus on the identification of the origin and the transport of this smoke plume. We use back trajectories calculated by the Canadian Meteorological Centre as well as FLEXPART forward trajectories to demonstrate that the enhanced CO, C2H6 and fine-mode AOD seen near Halifax and Toronto originated from forest fires in northwestern Ontario that occurred between 17 and 19 July 2011. In addition, total column measurements of CO from the satellite-borne Infrared Atmospheric Sounding Interferometer (IASI) have been used to trace the smoke plume and to confirm the origin of the CO enhancement. Furthermore, the enhancement ratio - that is, in this case equivalent to the emission ratio (ERC2H6/CO) - was estimated from these ground-based observations. These C2H6 emission results from boreal fires in northwestern Ontario agree well with C2H6 emission measurements from other boreal regions, and are relatively high compared to fires from other geographical regions. The ground-based CO and C2H6 observations were compared with outputs from the 3-D global chemical transport model GEOS-Chem, using the Fire Locating And Modeling of Burning Emissions (FLAMBE) inventory. Agreement within the stated measurement uncertainty (~ 3% for CO and ~ 8% for C2H6) was found for the magnitude of the enhancement of the CO and C2H6 total columns between the measured and modelled results. However, there is a small shift in time (of approximately 6 h) of arrival of the plume over Halifax between the results

Identifying the sources driving observed PM2.5 temporal variability over Halifax, Nova Scotia, during BORTAS-B

The source attribution of observed variability of total PM_2.5 concentrations over Halifax, Nova Scotia was investigated between 11 July–26 August 2011 using measurements of PM_2.5 mass and PM_2.5 chemical composition (black carbon, organic matter, anions, cations and 33 elements). This was part of the BORTAS-B (quantifying the impact of BOReal forest fires on Tropospheric oxidants using aircraft and satellites) experiment, which investigated the atmospheric chemistry and transport of seasonal boreal wild fire emissions over eastern Canada in 2011. The US EPA Positive Matrix Factorization (PMF) receptor model was used to determine the average mass (percentage) source contribution over the 45 days, which was estimated to be: Long-Range Transport (LRT) Pollution 1.75 μg m⁻³ (47%), LRT Pollution Marine Mixture 1.0 μg m⁻³ (27.9%), Vehicles 0.49 μg m⁻³ (13.2%), Fugitive Dust 0.23 μg m⁻³ (6.3%), Ship Emissions 0.13 μg m⁻³ (3.4%) and Refinery 0.081 μg m⁻³ (2.2%). The PMF model describes 87% of the observed variability in total PM_2.5 mass (bias = 0.17 and RSME = 1.5 μg m⁻³). The factor identifications are based on chemical markers, and they are supported by air mass back trajectory analysis and local wind direction. Biomass burning plumes, found by other surface and aircraft measurements, were not significant enough to be identified in this analysis. This paper presents the results of the PMF receptor modelling, providing valuable insight into the local and upwind sources impacting surface PM_2.5 in Halifax during the BORTAS-B mission

Ecteinascidin-743: Evidence of Activity in Advanced, Pretreated Soft Tissue and Bone Sarcoma Patients

Purpose. To evaluate the activity and safety of ecteinascidin (ET-743) in pretreated patients with advanced or metastatic soft tissue and bone sarcoma. Patients or subjects. Eighty-nine patients received ET-743 as a 24-hour continuous infusion at a dose of 900–1500 μg/m(2) every 3 weeks. Results. We observed one complete remission, 5 partial remissions, one minimal response, and 16 patients with a disease stabilization of 6 months or more. The objective response rate was 6.7% and the clinical benefit rate at 3 and 6 months was 37.7% and 23.4%, respectively. Responses were noted in patients with lipo-, leiomyo-, osteo-, and myogenic sarcoma, with a median duration of 9.85 months. Toxicity mainly involved an asymptomatic elevation of transaminases and neutropenia. Estimated 1- and 2-year survival rates were 39.4% and 15.8%. Median overall survival was 8.25 months. Discussion. This retrospective analysis confirms that ET-743 induces objective responses and progression arrest in a clinically relevant proportion of patients

Constructing Hybrid Baryons with Flux Tubes

Hybrid baryon states are described in quark potential models as having explicit excitation of the gluon degrees of freedom. Such states are described in a model motivated by the strong coupling limit of Hamiltonian lattice gauge theory, where three flux tubes meeting at a junction play the role of the glue. The adiabatic approximation for the quark motion is used, and the flux tubes and junction are modeled by beads which are attracted to each other and the quarks by a linear potential, and vibrate in various string modes. Quantum numbers and estimates of the energies of the lightest hybrid baryons are provided.Comment: 4 pages, RevTeX. Submitted to Physical Review Letter