Cosmological Solutions in String Theories

We obtain a large class of cosmological solutions in the toroidally-compactified low energy limits of string theories in $D$ dimensions. We consider solutions where a $p$-dimensional subset of the spatial coordinates, parameterising a flat space, a sphere, or an hyperboloid, describes the spatial sections of the physically-observed universe. The equations of motion reduce to Liouville or $SL(N+1,R)$ Toda equations, which are exactly solvable. We study some of the cases in detail, and find that under suitable conditions they can describe four-dimensional expanding universes. We discuss also how the solutions in $D$ dimensions behave upon oxidation back to the $D=10$ string theory or $D=11$ M-theory.Comment: Latex, 21 pages, a reference adjuste

“Wearing me place on me face”: Scousebrows, placemaking and everyday creativity

This paper emerges from a multidisciplinary research project called “Brews and Brows: Shaping Stories from Eyebrows to Scousebrows” that entailed gathering stories about eyebrow grooming from women and men from the city of Liverpool, UK, and creating a new taxonomy of the eyebrow where none currently exists. The point of departure for this paper is to challenge the negative commentary on the Scousebrow in the press and social media by engaging people in discussions surrounding the personal significance of eyebrow shaping and styling. In challenging this denigration, this paper uses data from in-depth interviews with eyebrow artists and clients and ethnographic interviews at a four-day event held in Liverpool. This paper argues that the everyday (little c) creative practice of eyebrow grooming is not only an important part of crafting and performing identity, particularly for Scouse women, but also an example of bottom-up placemaking in the city of Liverpool

Global overview of the management of acute cholecystitis during the COVID-19 pandemic (CHOLECOVID study)

Background: This study provides a global overview of the management of patients with acute cholecystitis during the initial phase of the COVID-19 pandemic. Methods: CHOLECOVID is an international, multicentre, observational comparative study of patients admitted to hospital with acute cholecystitis during the COVID-19 pandemic. Data on management were collected for a 2-month study interval coincident with the WHO declaration of the SARS-CoV-2 pandemic and compared with an equivalent pre-pandemic time interval. Mediation analysis examined the influence of SARS-COV-2 infection on 30-day mortality. Results: This study collected data on 9783 patients with acute cholecystitis admitted to 247 hospitals across the world. The pandemic was associated with reduced availability of surgical workforce and operating facilities globally, a significant shift to worse severity of disease, and increased use of conservative management. There was a reduction (both absolute and proportionate) in the number of patients undergoing cholecystectomy from 3095 patients (56.2 per cent) pre-pandemic to 1998 patients (46.2 per cent) during the pandemic but there was no difference in 30-day all-cause mortality after cholecystectomy comparing the pre-pandemic interval with the pandemic (13 patients (0.4 per cent) pre-pandemic to 13 patients (0.6 per cent) pandemic; P = 0.355). In mediation analysis, an admission with acute cholecystitis during the pandemic was associated with a non-significant increased risk of death (OR 1.29, 95 per cent c.i. 0.93 to 1.79, P = 0.121). Conclusion: CHOLECOVID provides a unique overview of the treatment of patients with cholecystitis across the globe during the first months of the SARS-CoV-2 pandemic. The study highlights the need for system resilience in retention of elective surgical activity. Cholecystectomy was associated with a low risk of mortality and deferral of treatment results in an increase in avoidable morbidity that represents the non-COVID cost of this pandemic

Delivery of ultrashort spatially focused pulses through a multimode fiber for two photon endoscopic imaging

Due to their high number of supported modes, multimode optical fibers carry large amount of spatio-temporal information. However, propagation of a light pulse through a multimode optical fiber suffers from spatial distortions due to superposition of the various exited modes and from time broadening due to modal dispersion. Here, we present a method based on digital phase conjugation to selectively excite specific optical fiber modes in a multimode fiber that follow similar optical paths as they travel through the fiber. In this way, they can be made to interfere constructively at the fiber output to generate an ultrashort spatially focused pulse. The excitation of a limited number of modes limits modal dispersion, allowing the transmission of an ultrashort pulse. We also show that the short spatially focused pulse can be scanned digitally without movable elements. We experimentally demonstrate that the pulse at the output of the multimode fiber generate a two-photon signal. We show delivery of a 1550 nm pulse with 500 fs duration, spatially focused to a spot size of 7 micrometers, through a 30 cm long, 200 micrometers core multimode step-index fiber. We show how this technique is applied to endoscopic two-photon imaging

Delivery of an ultrashort spatially focused pulse to the other end of a multimode fiber using digital phase conjugation

Multimode optical fibers potentially allow the transmission of larger amounts of information than their single mode counterparts because of their high number of supported modes. However, propagation of a light pulse through a multimode fiber suffers from spatial distortions due to the superposition of the various exited modes and from time broadening due to modal dispersion. We present a method based on digital phase conjugation to selectively excite in a multimode fiber specific optical fiber modes that follow similar optical paths as they travel through the fiber. The excited modes interfere constructively at the fiber output generating an ultrashort spatially focused pulse. The excitation of a limited number of modes following similar optical paths limits modal dispersion, allowing the transmission of the ultrashort pulse. We have experimentally demonstrated the delivery of a focused spot of pulse width equal to 500 fs through a 30 cm, 200 micrometer core step-index multimode fiber. The results of this study show that two-photon imaging capability can be added to ultra-thin lensless endoscopy using commercial multimode fibers

Expert systems for site location decisions

Considers the scope for applying expert system techniques to assist in decisions regarding site location. Begins with a review of the theoretical literature and assesses the progress made in developing computer models. Its central theme is that the next step forward in this area is to develop expert systems. Addresses the question of the design of an expert system which would improve the decision-making process. Concludes that such a system is well within the scope of current technology, as long as developers can avoid being overambitious and as long as the end result is highly user friendly

Use of mobile devices to measure outcomes in clinical research, 2010-2016: A systematic literature review

Introduction The use of mobile devices in clinical research has advanced substantially in recent years due to the rapid pace of technology development. With an overall aim of informing the future use of mobile devices in interventional clinical research to measure primary outcomes, we conducted a systematic review of the use of and clinical outcomes measured by mobile devices (mobile outcomes) in observational and interventional clinical research. Method We conducted a PubMed search using a range of search terms to retrieve peer-reviewed articles on clinical research published between January 2010 and May 2016, in which mobile devices were used to measure study outcomes. We screened each publication for specific inclusion and exclusion criteria. We then identified and qualitatively summarized the use of mobile outcome assessments in clinical research, including the type and design of the study, therapeutic focus, type of mobile device(s) used, and specific mobile outcomes reported. Results The search retrieved 2,530 potential articles of interest. After screening, 88 publications remained. Twenty-five percent of publications (n=22) described mobile outcomes used in interventional research, and the rest (n=66) described observational clinical research. Thirteen therapeutic areas were represented. Five categories of mobile devices were identified—inertial sensors, biosensors, pressure sensors and walkways, medication adherence monitors, and location monitors; inertial sensors/accelerometers were most common (reported in 86% of publications). Among the variety of mobile outcomes, various assessments of physical activity were most common (reported in 74% of publications). Other mobile outcomes included assessments of sleep, mobility, and pill adherence, as well as biomarkers assessed using a mobile device, including cardiac, glucose, gastric reflux, respiratory measures and intensity of head-related injury. Conclusion Mobile devices are being widely used in clinical research to assess outcomes, although their use in interventional research to assess therapeutic effectiveness is limited. For mobile devices to be used more frequently in pivotal interventional research – such as trials informing regulatory decision-making – more focus should be placed on: 1) consolidating the evidence supporting the clinical meaningfulness of specific mobile outcomes, and 2) standardizing the use of mobile devices in clinical research to measure specific mobile outcomes (e.g., data capture frequencies, placement of device). To that aim, this manuscript offers a broad overview of the various mobile outcome assessments currently used in observational and interventional research, and categorizes and consolidates this information for researchers interested in using mobile devices to assess outcomes in interventional research.</p

Use of Mobile Devices to Measure Outcomes in Clinical Research, 2010–2016: A Systematic Literature Review

Introduction The use of mobile devices in clinical research has advanced substantially in recent years due to the rapid pace of technology development. With an overall aim of informing the future use of mobile devices in interventional clinical research to measure primary outcomes, we conducted a systematic review of the use of and clinical outcomes measured by mobile devices (mobile outcomes) in observational and interventional clinical research. Method We conducted a PubMed search using a range of search terms to retrieve peer-reviewed articles on clinical research published between January 2010 and May 2016, in which mobile devices were used to measure study outcomes. We screened each publication for specific inclusion and exclusion criteria. We then identified and qualitatively summarized the use of mobile outcome assessments in clinical research, including the type and design of the study, therapeutic focus, type of mobile device(s) used, and specific mobile outcomes reported. Results The search retrieved 2,530 potential articles of interest. After screening, 88 publications remained. Twenty-five percent of publications (n=22) described mobile outcomes used in interventional research, and the rest (n=66) described observational clinical research. Thirteen therapeutic areas were represented. Five categories of mobile devices were identified—inertial sensors, biosensors, pressure sensors and walkways, medication adherence monitors, and location monitors; inertial sensors/accelerometers were most common (reported in 86% of publications). Among the variety of mobile outcomes, various assessments of physical activity were most common (reported in 74% of publications). Other mobile outcomes included assessments of sleep, mobility, and pill adherence, as well as biomarkers assessed using a mobile device, including cardiac, glucose, gastric reflux, respiratory measures and intensity of head-related injury. Conclusion Mobile devices are being widely used in clinical research to assess outcomes, although their use in interventional research to assess therapeutic effectiveness is limited. For mobile devices to be used more frequently in pivotal interventional research – such as trials informing regulatory decision-making – more focus should be placed on: 1) consolidating the evidence supporting the clinical meaningfulness of specific mobile outcomes, and 2) standardizing the use of mobile devices in clinical research to measure specific mobile outcomes (e.g., data capture frequencies, placement of device). To that aim, this manuscript offers a broad overview of the various mobile outcome assessments currently used in observational and interventional research, and categorizes and consolidates this information for researchers interested in using mobile devices to assess outcomes in interventional research.</p