Low-power methods of power sensing and frequency detection for wideband vibration energy harvesting

Power maximisation techniques in wideband vibration energy harvesting typically require the periodic sensing of input power or excitation frequency. This paper presents low- power circuits and sensing methods to obtain this information. First, an excitation frequency measurement circuit is presented that permits a reduced timer run-time compared to reported methods. Second, a power sensing method is presented, which extends the measurement range of reported techniques by adapting to the levels of the available power. Experimental results for the frequency measurement circuit tested in the range 35-51 Hz show a power consumption of 3.7 μW. The power-sensing technique is experimentally validated over a power range of 370690 μW, and its power consumption is 7.5 μW

Mechanical thrombectomy: can it be safely delivered out of hours in the UK?

BACKGROUND: Mechanical thrombectomy was approved by NICE as a treatment for stroke in 2016. However, most of the evidence is from studies conducted during working hours. Only few centres in the UK perform thrombectomies out-of-hours. The Royal Stoke University Hospital (RSUH) has offered thrombectomies over 24 h (24/7) since 2010. The aim of this service review is to compare the outcomes for patients treated in regular working hours to those treated outside normal working hours within this unit. METHODS: This retrospective service analysis includes all patients treated with mechanical thrombectomy at RSUH since the start of the service in January 2010 to June 2019. Data on key demographics, timings, procedural complications, and long-term outcomes including death and disability at 90 days were collected. In-hours was defined as the time between 8:00-17:00 h, Monday to Friday; out-of-hours was defined as any time outside this period. RESULTS: In total, 516 mechanical thrombectomies were performed in this time period; data were available on 501 of these. Successful recanalization (TICI 2b/3) was achieved in 86% of patients. By 90 days 96 (19%) had died and 234 (47%) were functionally independent (modified Rankin Scale score ≤ 2). 211 (42%) of the procedures were performed in-hours and 290 (58%) out-of-hours. Door-to-CT and door-to-groin times were significantly longer out-of-hours than in-hours, but thrombectomy duration was significantly shorter. There were no significant differences in complications and short- and long-term outcomes. CONCLUSION: Mechanical thrombectomy was delivered safely and effectively 24/7 in this UK hospital, with no difference in clinical outcomes

The comparative performance of three screening questionnaires for psoriatic arthritis in a primary care surveillance study.

Objectives To compare the performance of three psoriatic arthritis (PsA) screening questionnaires in a primary care psoriasis surveillance study. Methods Participants with psoriasis, and not known to have psoriatic arthritis (PsA), were identified from general practice databases and invited to attend a secondary care centre for a clinical assessment. The three patient-completed screening questionnaires (PEST, CONTEST, and CONTESTjt) were administered along with other patient reported measures and a clinical examination of skin and joints was performed. Participants who demonstrated signs of inflammatory arthritis suggestive of PsA were referred, via their GP, for a further assessment in a secondary care rheumatology clinic. Results A total of 791 participants attended the screening visit and 165 participants were judged to have signs and symptoms of inflammatory arthritis, of which 150 were referred for assessment. Of these 126 were seen and 48 were diagnosed with PsA. The results for each questionnaire were as follows: PEST: Sensitivity 0.625 (95% CI 0.482–0.749), specificity 0.757 (0.724–0.787). CONTEST: Sensitivity 0.604 (0.461–0.731), specificity 0.768 (0.736–0.798). CONTESTjt: Sensitivity 0.542 (0.401–0.676), specificity 0.834 (0.805–0.859). CONTESTjt demonstrated marginally superior specificity to PEST though the area under the ROC curve was similar for all three instruments. Conclusions Minimal differences between the three screening questionnaires were found in this study and no preference can be made based on these results. The choice of which instrument to choose will depend on other factors, such as simplicity and low patient burden

Incidence, patterns and severity of reported unintentional injuries in Pakistan for persons five years and older: results of the National Health Survey of Pakistan 1990–94

<p>Abstract</p> <p>Background</p> <p>National level estimates of injuries are not readily available for developing countries. This study estimated the annual incidence, patterns and severity of unintentional injuries among persons over five years of age in Pakistan.</p> <p>Methods</p> <p>National Health Survey of Pakistan (NHSP 1990–94) is a nationally representative survey of the household. Through a two-stage stratified design, 18, 315 persons over 5 years of age were interviewed to estimate the overall annual incidence, patterns and severity of unintentional injuries for males and females in urban and rural areas over the preceding one year. Weighted estimates were computed adjusting for complex survey design using <it>surveyfreq </it>and <it>surveylogistic </it>option of SAS 9.1 software.</p> <p>Results</p> <p>The overall annual incidence of all unintentional injuries was 45.9 (CI: 39.3–52.5) per 1000 per year; 59.2 (CI: 49.2–69.2) and 33.2 (CI: 27.0–39.4) per 1000 per year among males and females over five years of age, respectively. An estimated 6.16 million unintentional injuries occur in Pakistan annually among persons over five years of age. Urban and rural injuries were 55.9 (95% CI: 48.1–63.7) and 41.2 (95% CI: 32.2–50.0) per 1000 per year, respectively. The annual incidence of injuries due to falls were 22.2 (95% CI: 18.0–26.4), poisoning 3.3 (95%CI: 0.5–6.1) and burn was 1.5 (95%CI: 0.9–2.1) per 1000 per year. The majority of injuries occurred at home 19.2 (95%CI: 16.0–22.4) or on the roads 17.0 (95%CI: 13.8–20.2). Road traffic/street, school and urban injuries were more likely to result in handicap.</p> <p>Conclusion</p> <p>There is high burden of unintentional injuries among persons over five years of age in Pakistan. These results are useful to plan further studies and prioritizing prevention programs on injuries nationally and other developing countries with similar situation.</p

Female Chimpanzees Use Copulation Calls Flexibly to Prevent Social Competition

The adaptive function of copulation calls in female primates has been debated for years. One influential idea is that copulation calls are a sexually selected trait, which enables females to advertise their receptive state to males. Male-male competition ensues and females benefit by getting better mating partners and higher quality offspring. We analysed the copulation calling behaviour of wild female chimpanzees (Pan troglodytes schweinfurthii) at Budongo Forest, Uganda, but found no support for the male-male competition hypothesis. Hormone analysis showed that the calling behaviour of copulating females was unrelated to their fertile period and likelihood of conception. Instead, females called significantly more while with high-ranking males, but suppressed their calls if high-ranking females were nearby. Copulation calling may therefore be one potential strategy employed by female chimpanzees to advertise receptivity to high-ranked males, confuse paternity and secure future support from these socially important individuals. Competition between females can be dangerously high in wild chimpanzees, and our results indicate that females use their copulation calls strategically to minimise the risks associated with such competition

Plug-and-Play Power Resources and Agent-Based Coordination for Energy-Aware Wireless Sensor Nodes

A major constraint of sensor network deployments is their power supply: batteries have a limited lifetime and must be replaced when depleted. Recent advances in the field of energy harvesting mean that sensor nodes can now be powered by environmental energy such as light, vibration, or temperature differences; however, the variety of environments that sensor nodes are deployed into, and their varying levels of power consumption which is dependent on their operation, dictates the type of power supply which must be fitted to the node. This demonstration includes the work done at the University of Southampton in developing a plug-and-play energy architecture for sensor nodes that can accommodate a range of power sources and stores, and agent-based coordination which allows sensor nodes to negotiate between one another to allocate sensing tasks. These capabilities allow the sensor node to be energy-aware, with a flexible energy subsystem, to make best use of their available power. The demonstration is presented in two parts: (i) a plug-and-play energy architecture which is used to power a wireless sensor node, and (ii) a decentralized negotiation algorithm that is deployed on resource-constrained sensor nodes

The cost of link layer security in IoT embedded devices

Security of Internet of Things (IoT) devices is important for the acceptance of IoT applications. Several security mechanisms have been proposed, however, due to the limited resources in IoT devices, their overhead should be evaluated carefully. Many existing security solutions have been evaluated by simulation. However, with the increasing deployment of real nodes, a more accurate result based on real hardware is necessary. This research aims to evaluate the impact of applying security features of IEEE 802.15.4 on example hardware. The evaluation includes the impact on the Microcontroller Unit (MCU), radio, latency, packet throughput and transmission power. The results show that enabling software security services impact limited devices significantly. This impact could be translated into a decrease in throughput to almost 44%, an increase in latency and energy consumption to almost 197% and 86% respectively with maximum security level. The outcome of this paper is intended to benefit network designers and researchers by allowing them to model security overhead, allowing them to choose the security level, if enabled, which suits their application requirements.</p