An Optimal Control Approach to Flocking

Flocking behavior has attracted considerable attention in multi-agent systems. The structure of flocking has been predominantly studied through the application of artificial potential fields coupled with velocity consensus. These approaches, however, do not consider the energy cost of the agents during flocking, which is especially important in large-scale robot swarms. This paper introduces an optimal control framework to induce flocking in a group of agents. Guarantees of energy minimization and safety are provided, along with a decentralized algorithm that satisfies the optimality conditions and can be realized in real time. The efficacy of the proposed control algorithm is evaluated through simulation in both MATLAB and Gazebo.Comment: 6 pages, 4 figures. To appear at the 2020 American Control Conferenc

Cost-Consequence Analysis Alongside a Randomised Controlled Trial of Hospital Versus Telephone Follow-Up after Treatment for Endometrial Cancer

Background Regular outpatient follow-up programmes are usually offered to patients following treatment for gynaecological and other cancers. Despite the substantial resources involved in providing these programmes, there is evidence that routine follow-up programmes do not affect survival or the likelihood of detecting recurrence and may not meet patient needs. Alternative follow-up modalities may offer the same outcomes at lower cost. We examined the costs of using telephone-based routine follow-up of women treated for endometrial cancer undertaken by specialist gynaecology oncology nurses in comparison to routine hospital-based follow-up. Methods The ENDCAT trial randomised 259 women at five centres in the north west of England with a known diagnosis of Stage I endometrial cancer who had completed primary treatment on a 1:1 basis to receive either standard hospital outpatient follow-up or a telephone follow-up intervention administered by specialist nurses. A cost-consequence analysis was undertaken in which we compared costs to the health system and to individuals with the trial’s co-primary outcomes of psychological morbidity and participant satisfaction with information received. Results Psychological morbidity, psychosocial needs, patient satisfaction and quality of life did not differ between arms. Patients randomised to telephone follow-up underwent more and longer consultations. There was no difference in total health service mean per patient costs at 6 months (mean difference £8, 95% percentile confidence interval: − £147 to £141) or 12 months (mean difference: − £77, 95% percentile confidence interval: − £334 to £154). Estimated return journey costs per patient for hospital consultations were £11.47. Productivity costs were approximately twice as high under hospital follow-up. Conclusion Telephone follow-up was estimated to be cost-neutral for the NHS and may free up clinic time for other patients. There was some evidence that telephone follow-up may be more efficient for patients and wider society, and is not associated with additional psychological morbidity, lower patient satisfaction or reduced quality of life

Building nature’s safety net 2011 : the state of protected areas for Australia’s ecosystems and wildlife.

This report is the third in a series with the two previous reports published in 2006 and 2008. This report details major conservation initiatives that have occurred in Australia since the last report, in which data was current to 2006, and highlights emerging issues. A major enhancement on previous reports is the inclusion of ecosystem and threatened species gap analyses, and the reporting on Australia\u27s protected area systems on both land and sea. We define a minimum standard for an adequate, representative, and comprehensive reserve system by sampling ecosystem and species level diversity. Using the latest protected area and national species and ecosystem spatial data, we quantify the gaps: those areas needing to move from the current reserve system to one which meets the minimum standard. We also use data provided by various parks agencies, from responses to a questionnaire or as published by the agencies, to detail financial investments in protected areas, and estimate the investment levels needed to fill the documented gaps. We also identify critical policy changes needed to more effectively fill the identified gaps

Endometrial cancer patients’ preferences for follow-up after treatment: A cross-sectional survey

Purpose Alternatives to hospital follow-up (HFU) following treatment for cancer have been advocated. Telephone follow-up (TFU) and patient-initiated follow-up are being implemented but it is unclear if these approaches will meet the preferences and needs of patients. This study aimed to explore the preferences of endometrial cancer patients and their levels of satisfaction with HFU and nurse-led TFU. Methods A cross-sectional survey design was utilised and a questionnaire was administered to 236 patients who had participated in a randomised controlled trial comparing HFU with TFU for women diagnosed with Stage I endometrial cancer (ENDCAT trial). Results 211 (89.4%) patients returned the questionnaire; 105 in the TFU group and 106 in the HFU group. The TFU group were more likely to indicate that appointments were on time (p < 0.001) and were more likely to report that their appointments were thorough (p = 0.011). Participants tended to prefer what was familiar to them. Those in the HFU group tended to prefer hospital-based appointments while the TFU group tended to prefer appointments with a clinical nurse specialist, regardless of locality. Conclusions To provide patient centred follow-up services we need to ensure that patient preferences are taken into account and understand that patients may come to prefer what they have experienced. Patient initiated approaches may become standard and preferred practice but TFU remains a high-quality alternative to HFU and may provide an effective transition between HFU and patient-initiated approaches

Fine-scale simulation of ammonium and nitrate over the South Coast Air Basin and San Joaquin Valley of California during CalNex-2010

National ambient air quality standards (NAAQS) have been set for PM_2.5 due to its association with adverse health effects. PM_2.5 design values in the South Coast Air Basin (SoCAB) and San Joaquin Valley of California exceed NAAQS levels, and NH^(+)_(4) and NO^(-)_(3) make up the largest fraction of total PM2.5 mass on polluted days. Here we evaluate fine-scale simulations of PM_(2.5) NH^(+)_(4) and NO^(-)_(3) with the Community Multiscale Air Quality model using measurements from routine networks and the California Research at the Nexus of Air Quality and Climate Change 2010 campaign. The model correctly simulates broad spatial patterns of NH^(+)_(4) and NO^(-)_(3) including the elevated concentrations in eastern SoCAB. However, areas for model improvement have been identified. NH_3 emissions from livestock and dairy facilities appear to be too low, while those related to waste disposal in western SoCAB may be too high. Analyses using measurements from flights over SoCAB suggest that problems with NH3 predictions can influence NO^(-)_(3) predictions there. Offline ISORROPIA II calculations suggest that overpredictions of NH_x in Pasadena cause excessive partitioning of total nitrate to the particle phase overnight, while underpredictions of Na^+ cause too much partitioning to the gas phase during the day. Also, the model seems to underestimate mixing during the evening boundary layer transition leading to excessive nitrate formation on some nights. Overall, the analyses demonstrate fine-scale variations in model performance within and across the air basins. Improvements in inventories and spatial allocations of NH_3 emissions and in parameterizations of sea spray emissions, evening mixing processes, and heterogeneous ClNO_2 chemistry could improve model performance

Insect assemblages attacking seeds and fruits in a rainforest in Thailand

Insect seed predators are important agents of mortality for tropical trees, but little is known about the impact of these herbivores in rainforests. During three years at Khao Chong (KHC) in southern Thailand we reared 17,555 insects from 343.2 kg or 39,252 seeds/fruits representing 357 liana and tree species. A commented list of the 243 insect species identified is provided, with details about their host plants. We observed that: (1) about 43% of identified species can be considered pests. Most were seed eaters, particularly on dry fruits. (2) About 19% of parasitoid species (all Opiinae) for which we could determine whether their primary insect host was a pest or not (all Bactrocera spp. breeding in fruits) can be considered beneficials. (3) The seeds/fruits of about 28% of the plant species in this forest were free of attack. Phyllanthaceae, Rubiaceae, and Meliaceae were attacked relatively infrequently; in contrast, Annonaceae, Fabaceae, Sapindaceae, and Myristicaceae were more heavily attacked. There was no apparent effect of plant phylogeny on rates of attack but heavily attacked tree species had larger basal area in the KHC plot than rarely attacked tree species. (4) Insects reared from fleshy fruits were more likely to exhibit relatively stable populations compared to insects reared from dry fruits, but this was not true of insects reared from dipterocarps, which appeared to have relatively stable populations throughout the study period. We tentatively conclude that insects feeding on seeds and fruits have little effect on observed levels of host abundance in this forest

ERS statement on standardisation of cardiopulmonary exercise testing in chronic lung diseases

The objective of this document was to standardise published cardiopulmonary exercise testing (CPET) protocols for improved interpretation in clinical settings and multicentre research projects. This document: 1) summarises the protocols and procedures used in published studies focusing on incremental CPET in chronic lung conditions; 2) presents standard incremental protocols for CPET on a stationary cycle ergometer and a treadmill; and 3) provides patients’ perspectives on CPET obtained through an online survey supported by the European Lung Foundation. We systematically reviewed published studies obtained from EMBASE, Medline, Scopus, Web of Science and the Cochrane Library from inception to January 2017. Of 7914 identified studies, 595 studies with 26 523 subjects were included. The literature supports a test protocol with a resting phase lasting at least 3 min, a 3-min unloaded phase, and an 8- to 12-min incremental phase with work rate increased linearly at least every minute, followed by a recovery phase of at least 2–3 min. Patients responding to the survey (n=295) perceived CPET as highly beneficial for their diagnostic assessment and informed the Task Force consensus. Future research should focus on the individualised estimation of optimal work rate increments across different lung diseases, and the collection of robust normative data.The document facilitates standardisation of conducting, reporting and interpreting cardiopulmonary exercise tests in chronic lung diseases for comparison of reference data, multi-centre studies and assessment of interventional efficacy. http://bit.ly/31SXeB