DyMo: Dynamic Monitoring of Large Scale LTE-Multicast Systems

LTE evolved Multimedia Broadcast/Multicast Service (eMBMS) is an attractive solution for video delivery to very large groups in crowded venues. However, deployment and management of eMBMS systems is challenging, due to the lack of realtime feedback from the User Equipment (UEs). Therefore, we present the Dynamic Monitoring (DyMo) system for low-overhead feedback collection. DyMo leverages eMBMS for broadcasting Stochastic Group Instructions to all UEs. These instructions indicate the reporting rates as a function of the observed Quality of Service (QoS). This simple feedback mechanism collects very limited QoS reports from the UEs. The reports are used for network optimization, thereby ensuring high QoS to the UEs. We present the design aspects of DyMo and evaluate its performance analytically and via extensive simulations. Specifically, we show that DyMo infers the optimal eMBMS settings with extremely low overhead, while meeting strict QoS requirements under different UE mobility patterns and presence of network component failures. For instance, DyMo can detect the eMBMS Signal-to-Noise Ratio (SNR) experienced by the 0.1% percentile of the UEs with Root Mean Square Error (RMSE) of 0.05% with only 5 to 10 reports per second regardless of the number of UEs

Elastic microfibril distribution in the cornea: Differences between normal and keratoconic stroma

The optical and biomechanical properties of the cornea are largely governed by the collagen-rich stroma, a layer that represents approximately 90% of the total thickness. Within the stroma, the specific arrangement of superimposed lamellae provides the tissue with tensile strength, whilst the spatial arrangement of individual collagen fibrils within the lamellae confers transparency. In keratoconus, this precise stromal arrangement is lost, resulting in ectasia and visual impairment. In the normal cornea, we previously characterised the three-dimensional arrangement of an elastic fiber network spanning the posterior stroma from limbus-to-limbus. In the peripheral cornea/limbus there are elastin-containing sheets or broad fibers, most of which become microfibril bundles (MBs) with little or no elastin component when reaching the central cornea. The purpose of the current study was to compare this network with the elastic fiber distribution in post-surgical keratoconic corneal buttons, using serial block face scanning electron microscopy and transmission electron microscopy. We have demonstrated that the MB distribution is very different in keratoconus. MBs are absent from a region of stroma anterior to Descemet's membrane, an area that is densely populated in normal cornea, whilst being concentrated below the epithelium, an area in which they are absent in normal cornea. We contend that these latter microfibrils are produced as a biomechanical response to provide additional strength to the anterior stroma in order to prevent tissue rupture at the apex of the cone. A lack of MBs anterior to Descemet's membrane in keratoconus would alter the biomechanical properties of the tissue, potentially contributing to the pathogenesis of the disease

Demarginalizing Interdisciplinarity in IS Research: Interdisciplinary Research in Marginalization

This paper reports on the second Workshop of a World University Network (WUN) Research Development Funded project on “The trans-nationalization of Indigenous movements: The role of digital technologies” at the University of Southampton, UK. The workshop explored interdisciplinarity and how interdisciplinary collaboration can help scholars study complex social phenomenon, such as the ways in which marginalized Indigenous communities use and shape digital technologies (such as social media) to enhance their cause. The workshop brought together scholars from diverse disciplines to engage in a critical debate. In addition to scholars from information systems, scholars from history, political science, geography, literature, arts, and anthropology came together to discuss how marginalized Indigenous communities can use digital media. The workshop highlighted the need for more interdisciplinary research and called for more critical approaches to bring such marginalized topics to the forefront of research in information systems. We consider three broad areas of inquiry in this paper: demarginalizing methodology for interdisciplinary research, interdisciplinary perspectives for demarginalization, and interdisciplinary contexts for demarginalization

Observation-based modeling of ozone chemistry in the Seoul metropolitan area during the Korea-United States Air Quality Study (KORUS-AQ)

The Seoul Metropolitan Area (SMA) has a population of 24 million and frequently experiences unhealthy levels of ozone (O3). In this work, measurements taken during the Korea-United States Air Quality Study (KORUS-AQ, 2016) are used to explore regional gradients in O3 and its chemical precursors, and an observationally-constrained 0-D photochemical box model is used to quantify key aspects of O3 production including its sensitivity to precursor gases. Box model performance was evaluated by comparing modeled concentrations of select secondary species to airborne measurements. These comparisons indicate that the steady state assumption used in 0-D box models cannot describe select intermediate species, highlighting the importance of having a broad suite of trace gases as model constraints. When fully constrained, aggregated statistics of modeled O3 production rates agreed with observed changes in O3, indicating that the box model was able to represent the majority of O3 chemistry. Comparison of airborne observations between urban Seoul and a downwind receptor site reveal a positive gradient in O3 coinciding with a negative gradient in NOx, no gradient in CH2O, and a slight positive gradient in modeled rates of O3 production. Together, these observations indicate a radical-limited (VOC-limited) O3 production environment in the SMA. Zero-out simulations identified C7+ aromatics as the dominant VOC contributors to O3 production, with isoprene and anthropogenic alkenes making smaller but appreciable contributions. Simulations of model sensitivity to decreases in NOx produced results that were not spatially uniform, with large increases in O3 production predicted for urban Seoul and decreases in O3 production predicted for far-outlying areas. The policy implications of this work are clear: Effective O3 mitigation strategies in the SMA must focus on reducing local emissions of C7+ aromatics, while reductions in NOx emissions may increase O3 in some areas but generally decrease the regional extent of O3 exposure

Nocardiosis at a London teaching hospital: Be aware and beware of what is rare

Aims To review all laboratory-confirmed cases of nocardiosis at a tertiary referral hospital over an extended period (2000–2018; 216 months) with regard to microbiological and epidemiological characteristics, risk factors, clinical management, morbidity and mortality. Methods The medical records and microbiological data of all laboratory-confirmed cases of nocardiosis, identified by culture (with reference laboratory confirmation) or identified in a reference laboratory only, were included and analysed retrospectively. Results 18 cases of nocardiosis were identified; 72% (n = 13) were male; all were UK resident. Median age at presentation was 56 years (range 6–83 years). Most had underlying pathology or risk factors including cancer in 39% (n = 7) and immunosuppression in 33% (n = 6). Alcohol and acid fast bacilli (AAFB) microscopy performed in 8/18 cases was negative. Routine 48-hour bacterial culture of 18 isolates was positive in 15; 3 culture-negative specimens were subsequently confirmed positive in a reference laboratory. Four patterns of clinical presentation were observed: cerebral 39% (n = 7), disseminated 28% (n = 5), pulmonary 17% (n = 3), and isolated cutaneous/articular (both n = 1). In addition one case of bacteraemia was noted. Nocardia farcinica accounted for half (n = 9) of all nocardia species identified. 55% (n = 10) required surgical intervention. One co-trimoxazole resistant isolate was identified. Morbidity and mortality were high: 78% (n = 14) required critical care. More than half of patients (55%; n = 10) died from refractory infection, including all of those with disseminated disease (n = 5). Conclusions Nocardia spp should never be regarded as a contaminant or commensal organism in clinical specimens. Correlation of clinical and radiology findings plus risk factors are imperative for nocardiosis to be considered in the differential diagnosis in order to guide appropriate laboratory processing of specimens. Although rare, recognition of nocardiosis is important because of its high mortality. Routine 48-hour bacterial culture does not always identify Nocardia spp and isolates should also be sent to a reference laboratory

Comparing serial X-ray crystallography and microcrystal electron diffraction (MicroED) as methods for routine structure determination from small macromolecular crystals.

Innovative new crystallographic methods are facilitating structural studies from ever smaller crystals of biological macromolecules. In particular, serial X-ray crystallography and microcrystal electron diffraction (MicroED) have emerged as useful methods for obtaining structural information from crystals on the nanometre to micrometre scale. Despite the utility of these methods, their implementation can often be difficult, as they present many challenges that are not encountered in traditional macromolecular crystallography experiments. Here, XFEL serial crystallography experiments and MicroED experiments using batch-grown microcrystals of the enzyme cyclophilin A are described. The results provide a roadmap for researchers hoping to design macromolecular microcrystallography experiments, and they highlight the strengths and weaknesses of the two methods. Specifically, we focus on how the different physical conditions imposed by the sample-preparation and delivery methods required for each type of experiment affect the crystal structure of the enzyme

Synthesis of large-area multilayer hexagonal boron nitride for high material performance

Although hexagonal boron nitride (h-BN) is a good candidate for gate-insulating materials by minimizing interaction from substrate, further applications to electronic devices with available two-dimensional semiconductors continue to be limited by flake size. While monolayer h-BN has been synthesized on Pt and Cu foil using chemical vapour deposition (CVD), multilayer h-BN is still absent. Here we use Fe foil and synthesize large-area multilayer h-BN film by CVD with a borazine precursor. These films reveal strong cathodoluminescence and high mechanical strength (Young’s modulus: 1.16±0.1 TPa), reminiscent of formation of high-quality h-BN. The CVD-grown graphene on multilayer h-BN film yields a high carrier mobility of ~24,000 cm[superscript 2] V[superscript −1] s[superscript −1] at room temperature, higher than that (~13,000 [superscript 2] V[superscript −1] s[superscript −1]) with exfoliated h-BN. By placing additional h-BN on a SiO[subscript 2]/Si substrate for a MoS[subscript 2] (WSe[subscript 2]) field-effect transistor, the doping effect from gate oxide is minimized and furthermore the mobility is improved by four (150) times.Korea Institute of Science and Technology. Institutional ProgramNational Science Foundation (U.S.) (STC Center for Integrated Quantum Materials Grant DMR-1231319)Massachusetts Institute of Technology. Institute for Soldier Nanotechnologie