Encoderless Gimbal Calibration of Dynamic Multi-Camera Clusters

Dynamic Camera Clusters (DCCs) are multi-camera systems where one or more cameras are mounted on actuated mechanisms such as a gimbal. Existing methods for DCC calibration rely on joint angle measurements to resolve the time-varying transformation between the dynamic and static camera. This information is usually provided by motor encoders, however, joint angle measurements are not always readily available on off-the-shelf mechanisms. In this paper, we present an encoderless approach for DCC calibration which simultaneously estimates the kinematic parameters of the transformation chain as well as the unknown joint angles. We also demonstrate the integration of an encoderless gimbal mechanism with a state-of-the art VIO algorithm, and show the extensions required in order to perform simultaneous online estimation of the joint angles and vehicle localization state. The proposed calibration approach is validated both in simulation and on a physical DCC composed of a 2-DOF gimbal mounted on a UAV. Finally, we show the experimental results of the calibrated mechanism integrated into the OKVIS VIO package, and demonstrate successful online joint angle estimation while maintaining localization accuracy that is comparable to a standard static multi-camera configuration.Comment: ICRA 201

Do non-governmental organizations bring change or maintain the status quo in times of crisis? A case study of the Marikana massacre in South Africa.

This paper reflects on the Marikana massacre of August 2012, subsequent violent strikes and responses by non-governmental organisations (NGOs) as a case study, and provides an analysis about whether these interventions bring transformative change or maintain the status quo in times of crisis. Events associated with Marikana are seen to be embedded in social structures of the time and part of deeper frictions and fractures of social transformation (Alexander, 2013). The role that NGOs might play in this context, must be interrogated as to their facilitation or hinderance of such social transformation. Interviews were conducted with representatives of NGOs intervening in Marikana that provided services of humanitarian assistance, and legal and psychosocial interventions and with mine workers and residents of Marikana about their experiences and views of these services. Findings from the study are illustrative of how NGOs were not primarily motivated to bring about lasting, transformative change but rather attempted to address immediate or short-term needs which, while important, did not account for underlying causes of the crises that they set out to address. Both ideological underpinnings of NGOs and structural conditions produced by state and capital, impact on outcomes of interventions. Given these limitations, it is argued that there is a need for deep critical interrogation through praxis, for NGOs to intervene differently in times of crisis to bring ‘real’ change and transformation in the lives of those who are marginalized

Mothers’ sense of coherence in the face of their children’s struggles with substance abuse : a qualitative study

Developing from an apparent relationship between the theme of ill-health in mothers’ experiences of their children’s struggles with substance abuse and the concept of Sense of Coherence, this study focused on how mothers understood, managed, and made meaning of their children’s struggles with substance abuse. Semi-structured interviews were conducted with nine mothers whose young adult children had struggled with substance abuse. A theoretical thematic analysis revealed that the mothers moved between different understandings of their children’s struggles with substance abuse. The externalisation of responsibility was thought to represent a psychological resource which allowed the mothers to cope with feelings of guilt and shame. The mothers’ internalisation of responsibility for their children’s struggles with substance abuse contributed to a pattern of enmeshment, which in turn contributed to the mothers’ neglect of their own needs and well-being. This pattern of enmeshment continued until the mothers experienced a crisis of meaningfulness. This crisis helped the mothers to challenge their guilt and shame and allowed them to access resources which improved their Sense of Coherence and sense of well-being. Spiritual beliefs were found to be a resource that influenced how the mothers understood, managed and made meaning of their children’s struggles with substance abuse. The results of this study contribute to recommendations for organisations and professionals assisting mothers whose children may struggle with substance abuse

Sex-based differences in adolescents’ accuracy in perceiving and acceptance of parental socialisation values

The current study examined whether there are sex-based differences in adolescents’ accuracy in perceiving and acceptance of parental socialisation values. Together with their parents, a total of 134 adolescents (aged 13 to 18) from private Christian schools in Johannesburg, South Africa participated in the study. After creating the measures of overall accuracy, overall acceptance, specific accuracy and specific acceptance, a series of mixed-design ANOVAs were conducted in order to evaluate the six research hypotheses. The results illustrated that there may be sex-based differences in adolescents’ accuracy in perceiving the importance that their mothers and fathers place on the value of power as a socialisation value. However, the overall results suggested that the focus on the effect of adolescent sex on adolescents’ accuracy in perceiving and acceptance of parental socialisation values was too narrow because various parent sex and adolescent sex interaction effects were found. Furthermore, there is no clear pattern indicating how sex influences adolescents’ accuracy in perceiving and acceptance of parental socialisation values, thus suggesting that the influence of sex is value-specific.PsychologyM.A. (Psychology with specialisation in Research Consultation

Researching COVID to Enhance Recovery (RECOVER) Adult Study Protocol: Rationale, Objectives, and Design

IMPORTANCE: SARS-CoV-2 infection can result in ongoing, relapsing, or new symptoms or other health effects after the acute phase of infection; termed post-acute sequelae of SARS-CoV-2 infection (PASC), or long COVID. The characteristics, prevalence, trajectory and mechanisms of PASC are ill-defined. The objectives of the Researching COVID to Enhance Recovery (RECOVER) Multi-site Observational Study of PASC in Adults (RECOVER-Adult) are to: (1) characterize PASC prevalence; (2) characterize the symptoms, organ dysfunction, natural history, and distinct phenotypes of PASC; (3) identify demographic, social and clinical risk factors for PASC onset and recovery; and (4) define the biological mechanisms underlying PASC pathogenesis. METHODS: RECOVER-Adult is a combined prospective/retrospective cohort currently planned to enroll 14,880 adults aged ≥18 years. Eligible participants either must meet WHO criteria for suspected, probable, or confirmed infection; or must have evidence of no prior infection. Recruitment occurs at 86 sites in 33 U.S. states, Washington, DC and Puerto Rico, via facility- and community-based outreach. Participants complete quarterly questionnaires about symptoms, social determinants, vaccination status, and interim SARS-CoV-2 infections. In addition, participants contribute biospecimens and undergo physical and laboratory examinations at approximately 0, 90 and 180 days from infection or negative test date, and yearly thereafter. Some participants undergo additional testing based on specific criteria or random sampling. Patient representatives provide input on all study processes. The primary study outcome is onset of PASC, measured by signs and symptoms. A paradigm for identifying PASC cases will be defined and updated using supervised and unsupervised learning approaches with cross-validation. Logistic regression and proportional hazards regression will be conducted to investigate associations between risk factors, onset, and resolution of PASC symptoms. DISCUSSION: RECOVER-Adult is the first national, prospective, longitudinal cohort of PASC among US adults. Results of this study are intended to inform public health, spur clinical trials, and expand treatment options

Decline in subarachnoid haemorrhage volumes associated with the first wave of the COVID-19 pandemic

BACKGROUND: During the COVID-19 pandemic, decreased volumes of stroke admissions and mechanical thrombectomy were reported. The study\u27s objective was to examine whether subarachnoid haemorrhage (SAH) hospitalisations and ruptured aneurysm coiling interventions demonstrated similar declines. METHODS: We conducted a cross-sectional, retrospective, observational study across 6 continents, 37 countries and 140 comprehensive stroke centres. Patients with the diagnosis of SAH, aneurysmal SAH, ruptured aneurysm coiling interventions and COVID-19 were identified by prospective aneurysm databases or by International Classification of Diseases, 10th Revision, codes. The 3-month cumulative volume, monthly volumes for SAH hospitalisations and ruptured aneurysm coiling procedures were compared for the period before (1 year and immediately before) and during the pandemic, defined as 1 March-31 May 2020. The prior 1-year control period (1 March-31 May 2019) was obtained to account for seasonal variation. FINDINGS: There was a significant decline in SAH hospitalisations, with 2044 admissions in the 3 months immediately before and 1585 admissions during the pandemic, representing a relative decline of 22.5% (95% CI -24.3% to -20.7%, p\u3c0.0001). Embolisation of ruptured aneurysms declined with 1170-1035 procedures, respectively, representing an 11.5% (95%CI -13.5% to -9.8%, p=0.002) relative drop. Subgroup analysis was noted for aneurysmal SAH hospitalisation decline from 834 to 626 hospitalisations, a 24.9% relative decline (95% CI -28.0% to -22.1%, p\u3c0.0001). A relative increase in ruptured aneurysm coiling was noted in low coiling volume hospitals of 41.1% (95% CI 32.3% to 50.6%, p=0.008) despite a decrease in SAH admissions in this tertile. INTERPRETATION: There was a relative decrease in the volume of SAH hospitalisations, aneurysmal SAH hospitalisations and ruptured aneurysm embolisations during the COVID-19 pandemic. These findings in SAH are consistent with a decrease in other emergencies, such as stroke and myocardial infarction

Measurement of differential cross sections for top quark pair production using the lepton plus jets final state in proton-proton collisions at 13 TeV

National Science Foundation (U.S.

Particle-flow reconstruction and global event description with the CMS detector

The CMS apparatus was identified, a few years before the start of the LHC operation at CERN, to feature properties well suited to particle-flow (PF) reconstruction: a highly-segmented tracker, a fine-grained electromagnetic calorimeter, a hermetic hadron calorimeter, a strong magnetic field, and an excellent muon spectrometer. A fully-fledged PF reconstruction algorithm tuned to the CMS detector was therefore developed and has been consistently used in physics analyses for the first time at a hadron collider. For each collision, the comprehensive list of final-state particles identified and reconstructed by the algorithm provides a global event description that leads to unprecedented CMS performance for jet and hadronic tau decay reconstruction, missing transverse momentum determination, and electron and muon identification. This approach also allows particles from pileup interactions to be identified and enables efficient pileup mitigation methods. The data collected by CMS at a centre-of-mass energy of 8 TeV show excellent agreement with the simulation and confirm the superior PF performance at least up to an average of 20 pileup interactions

Identification of heavy-flavour jets with the CMS detector in pp collisions at 13 TeV

Many measurements and searches for physics beyond the standard model at the LHC rely on the efficient identification of heavy-flavour jets, i.e. jets originating from bottom or charm quarks. In this paper, the discriminating variables and the algorithms used for heavy-flavour jet identification during the first years of operation of the CMS experiment in proton-proton collisions at a centre-of-mass energy of 13 TeV, are presented. Heavy-flavour jet identification algorithms have been improved compared to those used previously at centre-of-mass energies of 7 and 8 TeV. For jets with transverse momenta in the range expected in simulated $\mathrm{t}\overline{\mathrm{t}}$ events, these new developments result in an efficiency of 68% for the correct identification of a b jet for a probability of 1% of misidentifying a light-flavour jet. The improvement in relative efficiency at this misidentification probability is about 15%, compared to previous CMS algorithms. In addition, for the first time algorithms have been developed to identify jets containing two b hadrons in Lorentz-boosted event topologies, as well as to tag c jets. The large data sample recorded in 2016 at a centre-of-mass energy of 13 TeV has also allowed the development of new methods to measure the efficiency and misidentification probability of heavy-flavour jet identification algorithms. The heavy-flavour jet identification efficiency is measured with a precision of a few per cent at moderate jet transverse momenta (between 30 and 300 GeV) and about 5% at the highest jet transverse momenta (between 500 and 1000 GeV)