Constrained trajectory optimization for kinematically redundant arms

Two velocity optimization schemes for resolving redundant joint configurations are compared. The Extended Moore-Penrose Technique minimizes the joint velocities and avoids obstacles indirectly by adjoining a cost gradient to the solution. A new method can incorporate inequality constraints directly to avoid obstacles and singularities in the workspace. A four-link arm example is used to illustrate singularity avoidance while tracking desired end-effector paths

An adaptive controller for enhancing operator performance during teleoperation

An adaptive controller is developed for adjusting robot arm parameters while manipulating payloads of unknown mass and inertia. The controller is tested experimentally in a master/slave configuration where the adaptive slave arm is commanded via human operator inputs from a master. Kinematically similar six-joint master and slave arms are used with the last three joints locked for simplification. After a brief initial adaptation period for the unloaded arm, the slave arm retrieves different size payloads and maneuvers them about the workspace. Comparisons are then drawn with similar tasks where the adaptation is turned off. Several simplifications of the controller dynamics are also addressed and experimentally verified

Influence of reheating on the trispectrum and its scale dependence

We study the evolution of the non-linear curvature perturbation during perturbative reheating, and hence how observables evolve to their final values which we may compare against observations. Our study includes the evolution of the two trispectrum parameters, \gnl and \taunl, as well as the scale dependence of both \fnl and \taunl. In general the evolution is significant and must be taken into account, which means that models of multifield inflation cannot be compared to observations without specifying how the subsequent reheating takes place. If the trispectrum is large at the end of inflation, it normally remains large at the end of reheating. In the classes of models we study, it is very hard to generate \taunl\gg\fnl^2, regardless of the decay rates of the fields. Similarly, for the classes of models in which \gnl\simeq\taunl during slow--roll inflation, we find the relation typically remains valid during reheating. Therefore it is possible to observationally test such classes of models without specifying the parameters of reheating, even though the individual observables are sensitive to the details of reheating. It is hard to generate an observably large \gnl however. The runnings, \nfnl and \ntaunl, tend to satisfy a consistency relation \ntaunl=(3/2)\nfnl, but are in general too small to be observed for the class of models considered regardless of reheating timescale

The Differences in Antibiotic Decision-making Between Acute Surgical and Acute Medical Teams: An Ethnographic Study of Culture and Team Dynamics

Background Cultural and social determinants influence antibiotic decision-making in hospitals. We investigated and compared cultural determinants of antibiotic decision-making in acute medical and surgical specialties. Methods An ethnographic observational study of antibiotic decision-making in acute medical and surgical teams at a London teaching hospital was conducted (August 2015–May 2017). Data collection included 500 hours of direct observations, and face-to-face interviews with 23 key informants. A grounded theory approach, aided by Nvivo 11 software, analyzed the emerging themes. An iterative and recursive process of analysis ensured saturation of the themes. The multiple modes of enquiry enabled cross-validation and triangulation of the findings. Results In medicine, accepted norms of the decision-making process are characterized as collectivist (input from pharmacists, infectious disease, and medical microbiology teams), rationalized, and policy-informed, with emphasis on de-escalation of therapy. The gaps in antibiotic decision-making in acute medicine occur chiefly in the transition between the emergency department and inpatient teams, where ownership of the antibiotic prescription is lost. In surgery, team priorities are split between 3 settings: operating room, outpatient clinic, and ward. Senior surgeons are often absent from the ward, leaving junior staff to make complex medical decisions. This results in defensive antibiotic decision-making, leading to prolonged and inappropriate antibiotic use. Conclusions In medicine, the legacy of infection diagnosis made in the emergency department determines antibiotic decision-making. In surgery, antibiotic decision-making is perceived as a nonsurgical intervention that can be delegated to junior staff or other specialties. Different, bespoke approaches to optimize antibiotic prescribing are therefore needed to address these specific challenges

Reheating with a composite Higgs boson

The flatness of the inflaton potential and lightness of the Higgs boson could have the common origin of the breaking of a global symmetry. This scenario provides a unified framework of Goldstone inflation and composite Higgs models, where the inflaton and the Higgs particle both have a pseudo-Goldstone boson nature. The inflaton reheats the Universe via decays to the Higgs and subsequent secondzary production of other SM particles via the top and massive vector bosons. We find that inflationary predictions and perturbative reheating conditions are consistent with cosmic microwave background data for sub-Planckian values of the fields, as well as opening up the possibility of inflation at the TeV scale. We explore this exciting possibility, leading to an interplay between collider data cosmological constraints

Eating well in care homes: Testing the feasibility of a staff training programme aimed at improving social interaction and choice at mealtimes

This is the author accepted manuscript. The final version is available from Wiley via the DOI in this recordThe health and well-being of care home residents are influenced by their experience of mealtimes, which provide an opportunity for residents to socialise and exercise control over their lives, as well as providing essential sustenance. Care home staff are pivotal to this experience, responsible for the provision of meals and eating assistance, but also for establishing a positive mealtime culture valued by residents. Despite this, mealtimes can be task-focussed, as the pressure on staff to perform multiple duties in limited time, or a lack of knowledge and awareness, means that resident needs and preferences risk being neglected. Methods: A staff-focussed training programme aimed at improving social interaction, and resident choice was developed and delivered in a workshop. Intervention feasibility was assessed using a qualitative survey and workshop observations. A combination of descriptive and content analyses was conducted on the data. Results: Thirteen women and one man took part in the workshops, representing multiple roles within two homes in the South West UK. The workshops were found to be deliverable and practicable. Participants responded positively to the workshops, anticipating that improvements to the mealtime experience would result from their workshop outputs. Conclusion: This study suggests that staff training workshops based on improving the mealtime experience are feasible to deliver within the day-to-day running of a care home and are acceptable to staff. Positive changes resulting from these workshops could improve the health and well-being of residents. Implications for practice: Mealtimes in care homes may be improved by increasing social interaction and by providing residents with greater choice. Management-faciltated staff training may be a useful tool to encourage staff to reflect on current practice and develop their own strategies to improve the mealtime experience for residents.National Institute for Health ResearchCollaboration for Leadership in Applied Health Research and Car

Effect of reheating on predictions following multiple-field inflation

We study the sensitivity of cosmological observables to the reheating phase following inflation driven by many scalar fields. We describe a method which allows semi-analytic treatment of the impact of perturbative reheating on cosmological perturbations using the sudden decay approximation. Focusing on $\mathcal{N}$-quadratic inflation, we show how the scalar spectral index and tensor-to-scalar ratio are affected by the rates at which the scalar fields decay into radiation. We find that for certain choices of decay rates, reheating following multiple-field inflation can have a significant impact on the prediction of cosmological observables.Comment: Published in PRD. 4 figures, 10 page

Opportunities for system level improvement in antibiotic use across the surgical pathway

Optimizing antibiotic prescribing across the surgical pathway (before, during, and after surgery) is a key aspect of tackling important drivers of antimicrobial resistance and simultaneously decreasing the burden of infection at the global level. In the UK alone, 10 million patients undergo surgery every year, which is equivalent to 60% of the annual hospital admissions having a surgical intervention. The overwhelming majority of surgical procedures require effectively limited delivery of antibiotic prophylaxis to prevent infections. Evidence from around the world indicates that antibiotics for surgical prophylaxis are administered ineffectively, or are extended for an inappropriate duration of time postoperatively. Ineffective antibiotic prophylaxis can contribute to the development of surgical site infections (SSIs), which represent a significant global burden of disease. The World Health Organization estimates SSI rates of up to 50% in postoperative surgical patients (depending on the type of surgery), with a particular problem in low- and middle-income countries, where SSIs are the most frequently reported healthcare-associated infections. Across European hospitals, SSIs alone comprise 19.6% of all healthcare-acquired infections. Much of the scientific research in infection management in surgery is related to infection prevention and control in the operating room, surgical prophylaxis, and the management of SSIs, with many studies focusing on infection within the 30-day postoperative period. However it is important to note that SSIs represent only one of the many types of infection that can occur postoperatively. This article provides an overview of the surgical pathway and considers infection management and antibiotic prescribing at each step of the pathway. The aim was to identify the implications for research and opportunities for system improvement