Like trainer, like bot? Inheritance of bias in algorithmic content moderation

The internet has become a central medium through which `networked publics' express their opinions and engage in debate. Offensive comments and personal attacks can inhibit participation in these spaces. Automated content moderation aims to overcome this problem using machine learning classifiers trained on large corpora of texts manually annotated for offence. While such systems could help encourage more civil debate, they must navigate inherently normatively contestable boundaries, and are subject to the idiosyncratic norms of the human raters who provide the training data. An important objective for platforms implementing such measures might be to ensure that they are not unduly biased towards or against particular norms of offence. This paper provides some exploratory methods by which the normative biases of algorithmic content moderation systems can be measured, by way of a case study using an existing dataset of comments labelled for offence. We train classifiers on comments labelled by different demographic subsets (men and women) to understand how differences in conceptions of offence between these groups might affect the performance of the resulting models on various test sets. We conclude by discussing some of the ethical choices facing the implementers of algorithmic moderation systems, given various desired levels of diversity of viewpoints amongst discussion participants.Comment: 12 pages, 3 figures, 9th International Conference on Social Informatics (SocInfo 2017), Oxford, UK, 13--15 September 2017 (forthcoming in Springer Lecture Notes in Computer Science

Mathematical properties of neuronal TD-rules and differential Hebbian learning: a comparison

A confusingly wide variety of temporally asymmetric learning rules exists related to reinforcement learning and/or to spike-timing dependent plasticity, many of which look exceedingly similar, while displaying strongly different behavior. These rules often find their use in control tasks, for example in robotics and for this rigorous convergence and numerical stability is required. The goal of this article is to review these rules and compare them to provide a better overview over their different properties. Two main classes will be discussed: temporal difference (TD) rules and correlation based (differential hebbian) rules and some transition cases. In general we will focus on neuronal implementations with changeable synaptic weights and a time-continuous representation of activity. In a machine learning (non-neuronal) context, for TD-learning a solid mathematical theory has existed since several years. This can partly be transfered to a neuronal framework, too. On the other hand, only now a more complete theory has also emerged for differential Hebb rules. In general rules differ by their convergence conditions and their numerical stability, which can lead to very undesirable behavior, when wanting to apply them. For TD, convergence can be enforced with a certain output condition assuring that the δ-error drops on average to zero (output control). Correlation based rules, on the other hand, converge when one input drops to zero (input control). Temporally asymmetric learning rules treat situations where incoming stimuli follow each other in time. Thus, it is necessary to remember the first stimulus to be able to relate it to the later occurring second one. To this end different types of so-called eligibility traces are being used by these two different types of rules. This aspect leads again to different properties of TD and differential Hebbian learning as discussed here. Thus, this paper, while also presenting several novel mathematical results, is mainly meant to provide a road map through the different neuronally emulated temporal asymmetrical learning rules and their behavior to provide some guidance for possible applications

Pulmonary symptoms and diagnoses are associated with HIV in the MACS and WIHS cohorts

Background: Several lung diseases are increasingly recognized as comorbidities with HIV; however, few data exist related to the spectrum of respiratory symptoms, diagnostic testing, and diagnoses in the current HIV era. The objective of the study is to determine the impact of HIV on prevalence and incidence of respiratory disease in the current era of effective antiretroviral treatment.Methods: A pulmonary-specific questionnaire was administered yearly for three years to participants in the Multicenter AIDS Cohort Study (MACS) and Women's Interagency HIV Study (WIHS). Adjusted prevalence ratios for respiratory symptoms, testing, or diagnoses and adjusted incidence rate ratios for diagnoses in HIV-infected compared to HIV-uninfected participants were determined. Risk factors for outcomes in HIV-infected individuals were modeled.Results: Baseline pulmonary questionnaires were completed by 907 HIV-infected and 989 HIV-uninfected participants in the MACS cohort and by 1405 HIV-infected and 571 HIV-uninfected participants in the WIHS cohort. In MACS, dyspnea, cough, wheezing, sleep apnea, and incident chronic obstructive pulmonary disease (COPD) were more common in HIV-infected participants. In WIHS, wheezing and sleep apnea were more common in HIV-infected participants. Smoking (MACS and WIHS) and greater body mass index (WIHS) were associated with more respiratory symptoms and diagnoses. While sputum studies, bronchoscopies, and chest computed tomography scans were more likely to be performed in HIV-infected participants, pulmonary function tests were no more common in HIV-infected individuals. Respiratory symptoms in HIV-infected individuals were associated with history of pneumonia, cardiovascular disease, or use of HAART. A diagnosis of asthma or COPD was associated with previous pneumonia.Conclusions: In these two cohorts, HIV is an independent risk factor for several respiratory symptoms and pulmonary diseases including COPD and sleep apnea. Despite a higher prevalence of chronic respiratory symptoms, testing for non-infectious respiratory diseases may be underutilized in the HIV-infected population. © 2014 Gingo et al.; licensee BioMed Central Ltd

Regional pulse wave velocities and their cardiovascular risk factors among healthy middle-aged men: A cross-sectional population-based study

Background: Both carotid-femoral (cf) pulse wave velocity (PWV) and brachial-ankle (ba) PWV employ arterial sites that are not consistent with the path of blood flow. Few previous studies have reported the differential characteristics between cfPWV and baPWV by simultaneously comparing these with measures of pure central (aorta) and peripheral (leg) arterial stiffness, i.e., heart-femoral (hf) PWV and femoral-ankle (fa) PWV in healthy populations. We aimed to identify the degree to which these commonly used measures of cfPWV and baPWV correlate with hfPWV and faPWV, respectively, and to evaluate whether both cfPWV and baPWV are consistent with either hfPWV or faPWV in their associations with cardiovascular (CV) risk factors.Methods: A population-based sample of healthy 784 men aged 40-49 (202 white Americans, 68 African Americans, 202 Japanese-Americans, and 282 Koreans) was examined in this cross-sectional study. Four regional PWVs were simultaneously measured by an automated tonometry/plethysmography system.Results: cfPWV correlated strongly with hfPWV (r = .81, P < .001), but weakly with faPWV (r = .12, P = .001). baPWV correlated moderately with both hfPWV (r = .47, P < .001) and faPWV (r = .62, P < .001). After stepwise regression analyses with adjustments for race, cfPWV shared common significant correlates with both hfPWV and faPWV: systolic blood pressure (BP) and body mass index (BMI). However, BMI was positively associated with hfPWV and cfPWV, and negatively associated with faPWV. baPWV shared common significant correlates with hfPWV: age and systolic BP. baPWV also shared the following correlates with faPWV: systolic BP, triglycerides, and current smoking.Conclusions: Among healthy men aged 40 - 49, cfPWV correlated strongly with central PWV, and baPWV correlated with both central and peripheral PWVs. Of the CV risk factors, systolic BP was uniformly associated with all the regional PWVs. In the associations with factors other than systolic BP, cfPWV was consistent with central PWV, while baPWV was consistent with both central and peripheral PWVs. © 2014 Choo et al.; licensee BioMed Central Ltd

Heterogeneity in Meta-Analyses of Genome-Wide Association Investigations

BACKGROUND: Meta-analysis is the systematic and quantitative synthesis of effect sizes and the exploration of their diversity across different studies. Meta-analyses are increasingly applied to synthesize data from genome-wide association (GWA) studies and from other teams that try to replicate the genetic variants that emerge from such investigations. Between-study heterogeneity is important to document and may point to interesting leads. METHODOLOGY/PRINCIPAL FINDINGS: To exemplify these issues, we used data from three GWA studies on type 2 diabetes and their replication efforts where meta-analyses of all data using fixed effects methods (not incorporating between-study heterogeneity) have already been published. We considered 11 polymorphisms that at least one of the three teams has suggested as susceptibility loci for type 2 diabetes. The I2 inconsistency metric (measuring the amount of heterogeneity not due to chance) was different from 0 (no detectable heterogeneity) for 6 of the 11 genetic variants; inconsistency was moderate to very large (I2 = 32-77%) for 5 of them. For these 5 polymorphisms, random effects calculations incorporating between-study heterogeneity revealed more conservative p-values for the summary effects compared with the fixed effects calculations. These 5 associations were perused in detail to highlight potential explanations for between-study heterogeneity. These include identification of a marker for a correlated phenotype (e.g. FTO rs8050136 being associated with type 2 diabetes through its effect on obesity); differential linkage disequilibrium across studies of the identified genetic markers with the respective culprit polymorphisms (e.g., possibly the case for CDKAL1 polymorphisms or for rs9300039 and markers in linkage disequilibrium, as shown by additional studies); and potential bias. Results were largely similar, when we treated the discovery and replication data from each GWA investigation as separate studies. SIGNIFICANCE: Between-study heterogeneity is useful to document in the synthesis of data from GWA investigations and can offer valuable insights for further clarification of gene-disease associations

Fear expression is suppressed by tyrosine administration

Animal studies have demonstrated that catecholamines regulate several aspects of fear conditioning. In humans, however, pharmacological manipulations of the catecholaminergic system have been scarce, and their primary focus has been to interfering with catecholaminergic activity after fear acquisition or expression had taken place, using L-Dopa, primarily, as catecholaminergic precursor. Here, we sought to determine if putative increases in presynaptic dopamine and norepinephrine by tyrosine administered before conditioning could affect fear expression. Electrodermal activity (EDA) of 46 healthy participants (24 placebo, 22 tyrosine) was measured in a fear instructed task. Results showed that tyrosine abolished fear expression compared to placebo. Importantly, tyrosine did not affect EDA responses to the aversive stimulus (UCS) or alter participants' mood. Therefore, the effect of tyrosine on fear expression cannot be attributed to these factors. Taken together, these findings provide evidence that the catecholaminergic system influences fear expression in humans

Alendronate and atrial fibrillation: a meta-analysis of randomized placebo-controlled clinical trials

Bone and mineral researc

Measurement of D-s(+) and D-s(*+) production in B meson decays and from continuum e(+)e(-) annihilation at √s=10.6 GeV

This is the pre-print version of the Article. The official published version can be accessed from the links below. Copyright @ 2002 APSNew measurements of Ds+ and Ds*+ meson production rates from B decays and from qq̅ continuum events near the Υ(4S) resonance are presented. Using 20.8 fb-1 of data on the Υ(4S) resonance and 2.6 fb-1 off-resonance, we find the inclusive branching fractions B(B⃗Ds+X)=(10.93±0.19±0.58±2.73)% and B(B⃗Ds*+X)=(7.9±0.8±0.7±2.0)%, where the first error is statistical, the second is systematic, and the third is due to the Ds+→φπ+ branching fraction uncertainty. The production cross sections σ(e+e-→Ds+X)×B(Ds+→φπ+)=7.55±0.20±0.34pb and σ(e+e-→Ds*±X)×B(Ds+→φπ+)=5.8±0.7±0.5pb are measured at center-of-mass energies about 40 MeV below the Υ(4S) mass. The branching fractions ΣB(B⃗Ds(*)+D(*))=(5.07±0.14±0.30±1.27)% and ΣB(B⃗Ds*+D(*))=(4.1±0.2±0.4±1.0)% are determined from the Ds(*)+ momentum spectra. The mass difference m(Ds+)-m(D+)=98.4±0.1±0.3MeV/c2 is also measured.This work was supported by DOE and NSF (USA), NSERC (Canada), IHEP (China), CEA and CNRS-IN2P3 (France), BMBF (Germany), INFN (Italy), NFR (Norway), MIST (Russia), and PPARC (United Kingdom). Individuals have received support from the Swiss NSF, A. P. Sloan Foundation, Research Corporation, and Alexander von Humboldt Foundation

Jet energy measurement with the ATLAS detector in proton-proton collisions at root s=7 TeV

The jet energy scale and its systematic uncertainty are determined for jets measured with the ATLAS detector at the LHC in proton-proton collision data at a centre-of-mass energy of √s = 7TeV corresponding to an integrated luminosity of 38 pb-1. Jets are reconstructed with the anti-kt algorithm with distance parameters R=0. 4 or R=0. 6. Jet energy and angle corrections are determined from Monte Carlo simulations to calibrate jets with transverse momenta pT≥20 GeV and pseudorapidities {pipe}η{pipe}<4. 5. The jet energy systematic uncertainty is estimated using the single isolated hadron response measured in situ and in test-beams, exploiting the transverse momentum balance between central and forward jets in events with dijet topologies and studying systematic variations in Monte Carlo simulations. The jet energy uncertainty is less than 2. 5 % in the central calorimeter region ({pipe}η{pipe}<0. 8) for jets with 60≤pT<800 GeV, and is maximally 14 % for pT<30 GeV in the most forward region 3. 2≤{pipe}η{pipe}<4. 5. The jet energy is validated for jet transverse momenta up to 1 TeV to the level of a few percent using several in situ techniques by comparing a well-known reference such as the recoiling photon pT, the sum of the transverse momenta of tracks associated to the jet, or a system of low-pT jets recoiling against a high-pT jet. More sophisticated jet calibration schemes are presented based on calorimeter cell energy density weighting or hadronic properties of jets, aiming for an improved jet energy resolution and a reduced flavour dependence of the jet response. The systematic uncertainty of the jet energy determined from a combination of in situ techniques is consistent with the one derived from single hadron response measurements over a wide kinematic range. The nominal corrections and uncertainties are derived for isolated jets in an inclusive sample of high-pT jets. Special cases such as event topologies with close-by jets, or selections of samples with an enhanced content of jets originating from light quarks, heavy quarks or gluons are also discussed and the corresponding uncertainties are determined. © 2013 CERN for the benefit of the ATLAS collaboration