There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality.

Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

I and i

Summary Background Since December, 2019, Wuhan, China, has experienced an outbreak of coronavirus disease 2019 (COVID-19), caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Epidemiological and clinical characteristics of patients with COVID-19 have been reported but risk factors for mortality and a detailed clinical course of illness, including viral shedding, have not been well described. Methods In this retrospective, multicentre cohort study, we included all adult inpatients (≥18 years old) with laboratory-confirmed COVID-19 from Jinyintan Hospital and Wuhan Pulmonary Hospital (Wuhan, China) who had been discharged or had died by Jan 31, 2020. Demographic, clinical, treatment, and laboratory data, including serial samples for viral RNA detection, were extracted from electronic medical records and compared between survivors and non-survivors. We used univariable and multivariable logistic regression methods to explore the risk factors associated with in-hospital death. Findings 191 patients (135 from Jinyintan Hospital and 56 from Wuhan Pulmonary Hospital) were included in this study, of whom 137 were discharged and 54 died in hospital. 91 (48%) patients had a comorbidity, with hypertension being the most common (58 [30%] patients), followed by diabetes (36 [19%] patients) and coronary heart disease (15 [8%] patients). Multivariable regression showed increasing odds of in-hospital death associated with older age (odds ratio 1·10, 95% CI 1·03–1·17, per year increase; p=0·0043), higher Sequential Organ Failure Assessment (SOFA) score (5·65, 2·61–12·23; p Interpretation The potential risk factors of older age, high SOFA score, and d-dimer greater than 1 μg/mL could help clinicians to identify patients with poor prognosis at an early stage. Prolonged viral shedding provides the rationale for a strategy of isolation of infected patients and optimal antiviral interventions in the future. Funding Chinese Academy of Medical Sciences Innovation Fund for Medical Sciences; National Science Grant for Distinguished Young Scholars; National Key Research and Development Program of China; The Beijing Science and Technology Project; and Major Projects of National Science and Technology on New Drug Creation and Development.

Clinical course and risk factors for mortality of adult inpatients with COVID-19 in Wuhan, China: a retrospective cohort study

With digital equipment becoming increasingly networked, either on wired or wireless networks, for personal and professional use alike, distributed software systems have become a crucial element in information and communications technologies. The study of these systems forms the core of the ARLES' work, which is specifically concerned with defining new system software architectures, based on the use of emerging networking technologies. In this context, we concentrate on the study of distributed systems which bring to life the vision of ubiquitous computing systems, also known as ambient intelligence.

반도체 공정 overview

Background: About a third of home-dwelling older people fall each year, and institutionalized older people even report a two- or threefold higher rate for falling

Sensitivity and false alarm rate of a fall sensor in long-term fall detection in the elderly

Mobile devices are becoming increasingly sophisticated and the latest generation of smart cell phones now incorporates many diverse and powerful sensors These sensors include GPS sensors, vision sensors (ie, cameras), audio sensors (ie, microphones), light sensors, temperature sensors, direction sensors (ie, magnetic compasses), and acceleration sensors (ie, accelerometers) The availability of these sensors in mass-marketed communication devices creates exciting new opportunities for data mining and data mining applications In this paper we describe and evaluate a system that uses phone-based accelerometers to perform activity recognition, a task which involves identifying the physical activity a user is performing To implement our system we collected labeled accelerometer data from twenty-nine users as they performed daily activities such as walking, jogging, climbing stairs, sitting, and standing, and then aggregated this time series data into examples that summarize the user activity over 10- second intervals We then used the resulting training data to induce a predictive model for activity recognition This work is significant because the activity recognition model permits us to gain useful knowledge about the habits of millions of users passively---just by having them carry cell phones in their pockets Our work has a wide range of applications, including automatic customization of the mobile device's behavior based upon a user's activity (eg, sending calls directly to voicemail if a user is jogging) and generating a daily/weekly activity profile to determine if a user (perhaps an obese child) is performing a healthy amount of exercise

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Activity recognition using cell phone accelerometers

The capacity to quickly and accurately simulate extracellular stimulation of neurons is essential to the design of next-generation neural prostheses. Existing platforms for simulating neurons are largely based on finite-difference techniques; due to the complex geometries involved, the more powerful spectral or differential quadrature techniques cannot be applied directly. This paper presents a mathematical basis for the application of a spectral element method to the problem of simulating the extracellular stimulation of retinal neurons, which is readily extensible to neural fibers of any kind. The activating function formalism is extended to arbitrary neuron geometries, and a segmentation method to guarantee an appropriate choice of collocation points is presented. Differential quadrature may then be applied to efficiently solve the resulting cable equations. The capacity for this model to simulate action potentials propagating through branching structures and to predict minimum extracellular stimulation thresholds for individual neurons is demonstrated. The presented model is validated against published values for extracellular stimulation threshold and conduction velocity for realistic physiological parameter values. This model suggests that convoluted axon geometries are more readily activated by extracellular stimulation than linear axon geometries, which may have ramifications for the design of neural prostheses.

A spectral element method with adaptive segmentation for accurately simulating extracellular electrical stimulation of neurons.

Visual Prostheses: Neuroengineering Handbook

Retinal ganglion cells (RGCs) in the vertebrate retina display a wide range of dendritic morphologies. In order to isolate the contribution of this physical property, we employed a neural morphology generator to study the differences in firing patterns among RGCs with different dendritic geometrical factors but with identical voltage-gated channel kinetics and distributions. Our results suggest that cell morphology alone is sufficient to generate quantitatively distinct electrophysiological responses, serving as a basis for understanding how structural factors influence RGC behavior.

Influence of retinal ganglion cell morphology on neuronal response properties - a simulation study

The design and evaluation of a Web-based system in which a longitudinal clinical record is used for management of cystic fibrosis, is described. In the home, a low-cost, PC-based spirometry module will be used for the acquisition of lung function measurements using a standard web browser interface. An electronic diary will be used to record symptoms of cough, mucus, activity, appetite, weight, breathing, mood and fever. The patient's clinical record will be maintained on a centralised server. An intelligent software agent on the Web server is activated whenever new patient data is collected remotely from the home. The agent compares historical data with newly acquired data. Using this method, an optimum patient care strategy can be evaluated, with reminders and suggestions for action sent to the doctor and patient by email. A two-stage evaluation will be carried out to assess the effectiveness of home monitoring in cystic fibrosis. In addition to the home diary, qualitative and quantitative measures including the NIH scoring system, the CFQoL questionnaire, interviews and observations will be used in the study. The system will initially be deployed at Sydney Children's Hospital where 15 patients will be recruited from the Cystic Fibrosis Clinic and trained to use the system. The system will then be installed in these patient's homes to determine the clinical utility of a longitudinal clinical record and feasibility of the design for management of cystic fibrosis.

Development and Evaluation of a Web-based System for Home Monitoring in Cystic Fibrosis

Indoor localization and asset tracking is an area of research which is finding increasing application in monitoring the wellbeing of elderly subjects in hospital or residential care environments. Radio frequency (RF) based localization methods tend to show poor performance in indoor environments, due to multipath scatter, and simple room-level misassociations, resulting from the relative transparency of some walls to RF waves. Ultrasound (US) localization has shown excellent room-level accuracy, and as US will not easily penetrate walls, room-level misassociations do not often occur. For normal asset tracking systems, the association between an asset and a room is not of critical importance; for clinical applications, which make inferences based on a patient and carer occupying the same room, this association is paramount. This paper outlines a proof of concept for an US-based indoor localization system with sub-room-level accuracy. The proposed design uses a US-based technique, with transmitter beacons placed throughout the environment. The subject wears the receiver module and is free to move throughout the environment. Transmission collisions are alleviated by assigning a unique prime transmission interval to each beacon; meaning the beacons do not require synchronization or coordination and operate independently of one another. Preliminary results show accurate detection at a range of over 5 m at a 0° angle and at approximately 3.5 m at an angle of 30°. Testing of two collocated transmitters, transmitting in the same plane and separated by 2.5 m results in accurate reception of both signals, even within the region of overlap.

Nigel H. Lovell

Papers

A spectral element method with adaptive segmentation for accurately simulating extracellular electrical stimulation of neurons.

Visual Prostheses: Neuroengineering Handbook

Influence of retinal ganglion cell morphology on neuronal response properties - a simulation study

Development and Evaluation of a Web-based System for Home Monitoring in Cystic Fibrosis

Ultrasound user-identification for wireless sensor networks