Dynamic Reconstruction and Multivariable Control for Force-Actuated, Thin Facesheet Adaptive Optics

The Multiple Mirror Telescope (MMT) under development at the University of Arizona takes a new approach in adaptive optics placing a large (0.65 m) force-actuated, thin facesheet deformable mirror at the secondary of an astronomical telescope, thus reducing the effects of emissivity which are important in IR astronomy. However, The large size of the mirror and low stiffness actuators used drive the natural frequencies of the mirror down into the bandwidth of the atmospheric distortion. Conventional adaptive optics takes a quasi-static approach to controlling the, deformable mirror. However, flexibility within the control bandwidth calls for a new approach to adaptive optics. Dynamic influence functions are used to characterize the influence of each actuator on the surface of the deformable mirror. A linearized model of atmospheric distortion is combined with dynamic influence functions to produce a dynamic reconstructor. This dynamic reconstructor is recognized as an optimal control problem. Solving the optimal control problem for a system with hundreds of actuators and sensors is formidable. Exploiting the circularly symmetric geometry of the mirror, and a suitable model of atmospheric distortion, the control problem is divided into a number of smaller decoupled control problems using circulant matrix theory. A hierarchic control scheme which seeks to emulate the quasi-static control approach that is generally used in adaptive optics is compared to the proposed dynamic reconstruction technique. Although dynamic reconstruction requires somewhat more computational power to implement, it achieves better performance with less power usage, and is less sensitive than the hierarchic technique

The Postoperative Morbidity Survey was validated and used to describe morbidity after major surgery.

OBJECTIVES: To describe the reliability and validity of the Postoperative Morbidity Survey (POMS). To describe the level and pattern of short-term postoperative morbidity after major elective surgery using the POMS. STUDY DESIGN AND SETTING: This was a prospective cohort study of 439 adults undergoing major elective surgery in a UK teaching hospital. The POMS, an 18-item survey that address nine domains of postoperative morbidity, was recorded on postoperative days 3, 5, 8, and 15. RESULTS: Inter-rater reliability was perfect for 11/18 items (Kappa=1.0), with Kappa=0.94 for 6/18 items. A priori hypotheses that the POMS would discriminate between patients with known measures of morbidity risk, and predict length of stay were generally supported through observation of data trends, and there was statistically significant evidence of construct validity for all but the wound and neurological domains. POMS-defined morbidity was present in 325 of 433 patients (75.1%) remaining in hospital on postoperative day 3 after surgery, 231 of 407 patients (56.8%) on day 5, 138 of 299 patients (46.2%) on day 8, and 70 of 111 patients (63.1%) on day 15. Gastrointestinal (47.4%), infectious (46.5%), pain-related (40.3%), pulmonary (39.4%), and renal problems (33.3%) were the most common forms of morbidity. CONCLUSION: The POMS is a reliable and valid survey of short-term postoperative morbidity in major elective surgery. Many patients remain in hospital without any morbidity as recorded by the POMS

Changes in labial capillary density on ascent to and descent from high altitude.

Present knowledge of how the microcirculation is altered by prolonged exposure to hypoxia at high altitude is incomplete and modification of existing analytical techniques may improve our knowledge considerably. We set out to use a novel simplified method of measuring in vivo capillary density during an expedition to high altitude using a CytoCam incident dark field imaging video-microscope. The simplified method of data capture involved recording one-second images of the mucosal surface of the inner lip to reveal data about microvasculature density in ten individuals. This was done on ascent to, and descent from, high altitude. Analysis was conducted offline by two independent investigators blinded to the participant identity, testing conditions and the imaging site.  Additionally we monitored haemoglobin concentration and haematocrit data to see if we could support or refute mechanisms of altered density relating to vessel recruitment. Repeated sets of paired values were compared using Kruskall Wallis Analysis of Variance tests, whilst comparisons of values between sites was by related samples Wilcoxon Signed Rank Test. Correlation between different variables was performed using Spearman's rank correlation coefficient, and concordance between analysing investigators using intra-class correlation coefficient. There was a significant increase in capillary density from London on ascent to high altitude; median capillaries per field of view area increased from 22.8 to 25.3 (p=0.021). There was a further increase in vessel density during the six weeks spent at altitude (25.3 to 32.5, p=0.017). Moreover, vessel density remained high on descent to Kathmandu (31.0 capillaries per field of view area), despite a significant decrease in haemoglobin concentration and haematocrit. Using a simplified technique, we have demonstrated an increase in capillary density on early and sustained exposure to hypobaric hypoxia at thigh altitude, and that this remains elevated on descent to normoxia. The technique is simple, reliable and reproducible

Early identification of wound infection: understanding wound odour

Malodorous wounds can be distressing for patients and their families, negatively impacting on quality-of-life outcomes. For health professionals malodorous wounds can also cause distress manifesting in feelings of disgust when faced with a wound emitting an unpleasant or repulsive odour. There has been investigation into the management of controlling odour particularly in relation to fungating wounds. However, there is limited research that explores techniques for early identification and recognition of wound odours that may be indicative of infection. Electronic nose technology has received some attention, but to date has not been integrated into either diagnostics of infection in wounds or education of health professionals to prepare them for the realities of clinical practice

Predictors of treatment outcome in depression in later life: a systematic review and meta-analysis

Background: Predictor analyses of late-life depression can be used to identify variables associated with outcomes of treatments, and hence ways of tailoring specific treatments to patients. The aim of this review was to systematically identify, review and meta-analyse predictors of outcomes of any type of treatment for late-life depression. Methods: Pubmed, Embase, CINAHL, Web of Science and PsycINFO were searched for studies published up to December 2016. Primary and secondary studies reported treatment predictors from randomised controlled trials of any treatment for patients with major depressive disorder aged over 60 were included. Treatment outcomes included response, remission and change in depression score. Results: Sixty-seven studies met the inclusion criteria. Of 65 identified statistically significant predictors, only 7 were reported in at least 3 studies. Of these, 5 were included in meta-analyses, and only 3 were statistically significant. Most studies were rated as being of moderate to strong quality and satisfied key quality criteria for predictor analyses. Limitations: The searches were limited to randomised controlled trials and most of the included studies were secondary analyses. Conclusions: Baseline depression severity, co-morbid anxiety, executive dysfunction, current episode duration, early improvement, physical illnesses and age were reported as statistically significant predictors of treatment outcomes. Only the first three were significant in meta-analyses. Subgroup analyses showed differences in predictor effect between biological and psychosocial treatment. However, high heterogeneity and small study numbers suggest a cautious interpretation of results. These predictors were associated with various mechanisms including brain pathophysiology, perceived social support and proposed distinct types of depressive disorder. Further investigation of the clinical utility of these predictors is suggested

Anarchy in the UK('s most famous fortress): comradeship and cupidity in Gibraltar and neighbouring Spain, 1890-1902

This article is the first to investigate the growth of anarchist ideology and tactics in Gibraltar and the surrounding Spanish region, the Campo de Gibraltar, in the period 1890-1902. We draw upon hitherto unused material from both The National Archives in London and the Gibraltar Government Archives. By doing so, we demonstrate that during this period Gibraltarian and Spanish workers came together, not only to defend and advance their interests by direct action, such as strikes and attacks on employers, but also to advance educational and social causes too. Indeed, by 1898-9 the appeal of this movement was so strong that an attempt by the British Social Democratic Federation to establish a more constitutionalist approach to industrial relations failed. By 1902, the power of anarchist movements and tactics concerned employers in Gibraltar so greatly that they engineered a lock-out – styled a general strike by local workers – and successfully smashed the organising power of the local movement. Meanwhile, on the Spanish side of the frontier a massacre engineered by the local Spanish authorities resulted in the deaths of a number of activists and a hiatus in the movement that would last until the Great War of 1914-18

Randomized controlled trial of intraoperative goal-directed fluid therapy in aerobically fit and unfit patients having major colorectal surgery.

BACKGROUND: Intraoperative fluid therapy regimens using oesophageal Doppler monitoring (ODM) to optimize stroke volume (SV) (goal-directed fluid therapy, GDT) have been associated with a reduction in length of stay (LOS) and complication rates after major surgery. We hypothesized that intraoperative GDT would reduce the time to surgical readiness for discharge (RfD) of patients having major elective colorectal surgery but that this effect might be less marked in aerobically fit patients. METHODS: In this double-blinded controlled trial, 179 patients undergoing major open or laparoscopic colorectal surgery were characterized as aerobically 'fit' (n=123) or 'unfit' (n=56) on the basis of their performance during a cardiopulmonary exercise test. Within these fitness strata, patients were randomized to receive a standard fluid regimen with or without ODM-guided intraoperative GDT. RESULTS: GDT patients received an average of 1360 ml of additional intraoperative colloid. The mean cardiac index and SV at skin closure were significantly higher in the GDT group than in controls. Times to RfD and LOS were longer in GDT than control patients but did not reach statistical significance (median 6.8 vs 4.9 days, P=0.09, and median 8.8 vs 6.7 days, P=0.09, respectively). Fit GDT patients had an increased RfD (median 7.0 vs 4.7 days; P=0.01) and LOS (median 8.8 vs 6.0 days; P=0.01) compared with controls. CONCLUSIONS: Intraoperative SV optimization conferred no additional benefit over standard fluid therapy. In an aerobically fit subgroup of patients, GDT was associated with detrimental effects on the primary outcome. TRIAL REGISTRY: UK NIHR CRN 7285, ISRCTN 14680495. http://public.ukcrn.org.uk/Search/StudyDetail.aspx?StudyID=7285