1,470 research outputs found
Higher cyclic operads
We introduce a convenient definition for weak cyclic operads, which is based on unrooted trees and Segal conditions. More specifically, we introduce a category of trees, which carries a tight relationship to the Moerdijk-Weiss category of rooted trees . We prove a nerve theorem exhibiting colored cyclic operads as presheaves on which satisfy a Segal condition. Finally, we produce a Quillen model category whose fibrant objects satisfy a weak Segal condition, and we consider these objects as an up-to-homotopy generalization of the concept of cyclic operad
Airship economics
Projected operating and manufacturing costs of a large airship design which are considered practical with today's technology and environment are discussed. Data and information developed during an 18-month study on the question of feasibility, engineering, economics and production problems related to a large metalclad type airship are considered. An overview of other classic airship designs are provided, and why metalclad was selected as the most prudent and most economic design to be considered in the 1970-80 era is explained. Crew operation, ATC and enroute requirements are covered along with the question of handling, maintenance and application of systems to the large airship
Dynamic concentration of motors in microtubule arrays
We present experimental and theoretical studies of the dynamics of molecular
motors in microtubule arrays and asters. By solving a convection-diffusion
equation we find that the density profile of motors in a two-dimensional aster
is characterized by continuously varying exponents. Simulations are used to
verify the assumptions of the continuum model. We observe the concentration
profiles of kinesin moving in quasi two-dimensional artificial asters by
fluorescent microscopy and compare with our theoretical results.Comment: 4pages, 4 figures revte
Quasi-simultaneous observations of the BL Lac object MK 501 in X-ray, UV, visible, IR and radio frequencies
Quasi-simultaneous observations of the BL Lacertae (Lac) objects MK 501 were performed for the first time at X-ray, ultraviolet, visible, infrared, and radio frequencies. The observed spectral slope from the X-ray to UV regions is positive and continuous, but that from the mid UV to visible light region becomes gradually flat and possibly turns down toward lower frequencies; the optical radio emission can not be accounted for by a single power law. Several theoretical models were considered for the emission mechanism. A quantitative comparison was performed with the synchrotron-self-Compton model; the total spectrum is found consistent with this model. The spectrum from visible light to X-ray is consistent with synchrotron radiation or with inverse-Compton scattering by a hot thermal cloud of electrons. The continuity of the spectral slope from X-ray to UV implied by the current data suggests that the previous estimates of the total luminosity of this BL Lac object is underestimated by a factor of about three or four
The homotopy theory of simplicial props
The category of (colored) props is an enhancement of the category of colored
operads, and thus of the category of small categories. In this paper, the
second in a series on "higher props," we show that the category of all small
colored simplicial props admits a cofibrantly generated model category
structure. With this model structure, the forgetful functor from props to
operads is a right Quillen functor.Comment: Final version, to appear in Israel J. Mat
Challenges for ‘Green IT’ in the Scottish ADM industry
Our research reports specifically on the challenges and behaviours towards ‘Green IT’ experienced within one complex industry. We adopt a theoretical stance based upon Unified Theory of Acceptance and Use of Technology (UTAUT) to formulate an outline ‘Green IT’ agenda. We draw on historical thinking which underpins UTAUT, which can be traced back to the theory of reasoned action (TRA) and the frequently adopted technology acceptance model (TAM). Recent research on the business case for a green IT strategy identifies benefits to an enterprise’s revenue and/or cost rather than just its image making. In this respect, empirical evidence was collected and analysed from the Aerospace, Defence and Marine (ADM) industry in Scotland which includes over 800 companies employing nearly 40,000 staff which creates Gross Value Adding to the Scottish economy of around £2 billion. Data collection involved an on-line based semi structured questionnaire to all 180 Aerospace and Defence organisations using the Scottish Enterprise Database. Our findings suggest a need to develop unified measurements to evaluate green IT progress. Specifically, these should include a metric capable of measuring IT companies’ net environmental activism, assessing not only the impact of changes but also on the operations and products of their clients
Modulation of outer bank erosion by slump blocks: Disentangling the protective and destructive role of failed material on the three-dimensional flow structure
The three-dimensional flow field near the banks of alluvial channels is the primary factor controlling rates of bank erosion. Although submerged slump blocks and associated large-scale bank roughness elements have both previously been proposed to divert flow away from the bank, direct observations of the interaction between eroded bank material and the 3-D flow field are lacking. Here we use observations from multibeam echo sounding, terrestrial laser scanning, and acoustic Doppler current profiling to quantify, for the first time, the influence of submerged slump blocks on the near-bank flow field. In contrast to previous research emphasizing their influence on flow diversion away from the bank, we show that slump blocks may also deflect flow onto the bank, thereby increasing local shear stresses and rates of erosion. We use our measurements to propose a conceptual model for how submerged slump blocks interact with the flow field to modulate bank erosion.UK Natural Environment Research Council (NERC
The Nature and Purpose of Acute Psychiatric Wards: The Tompkins Acute Ward Study
Background: Acute inpatient care in the UK is being subjected to increasing critical scrutiny, highlighting concerns about content and quality. There is an absence of clarity and consensus on what acute inpatient care is for, adding to difficulties in developing this service sector.
Aim: To define the function of acute psychiatric wards.
Methods: Interviews were conducted with multidisciplinary staff (13 Ward Managers, 14 F Grade nurses, 11 Occupational Therapists and 9 Consultant Psychiatrists), on rationales for admission, their care and treatment philosophy, and the roles of different professionals.
Results: Patients are admitted because they appear likely to harm themselves or others, and because they are suffering from a severe mental illness, and/or because they or their family/community require respite, and/or because they have insufficient support and supervision available to them in the community. The tasks of acute inpatient care are to keep patients safe, assess their problems, treat their mental illness, meet their basic care needs and provide physical healthcare. These tasks are completed via containment, 24-hour staff presence, treatment provision, and complex organisation and management.
Conclusions: Professional education, audit, research and the structuring of services all need to be oriented towards these tasks.
Declaration of interest: This study was funded by the Tompkins Foundation and the Department of Health Nursing Quality initiative
'Treatment of the Sportsman's groin': British Hernia Society's 2014 position statement based on the Manchester Consensus Conference
<b>Introduction</b> The aim was to produce a multidisciplinary consensus to determine the current position on the nomenclature, definition, diagnosis, imaging modalities and management of Sportsman's groin (SG).<p></p>
<b>Methods</b> Experts in the diagnosis and management of SG were invited to participate in a consensus conference held by the British Hernia Society in Manchester, UK on 11–12 October 2012. Experts included a physiotherapist, a musculoskeletal radiologist and surgeons with a proven track record of expertise in this field. Presentations detailing scientific as well as outcome data from their own experiences were given. Records were made of the presentations with specific areas debated openly.<p></p>
<b>Results</b> The term ‘inguinal disruption’ (ID) was agreed as the preferred nomenclature with the term ‘Sportsman's hernia’ or ‘groin’ rejected, as no true hernia exists. There was an overwhelming agreement of opinion that there was abnormal tension in the groin, particularly around the inguinal ligament attachment. Other common findings included the possibility of external oblique disruption with consequent small tears noted as well as some oedema of the tissues. A multidisciplinary approach with tailored physiotherapy as the initial treatment was recommended with any surgery involving releasing the tension in the inguinal canal by various techniques and reinforcing it with a mesh or suture repair. A national registry should be developed for all athletes undergoing surgery.<p></p>
<b>Conclusions</b> ID is a common condition where no true hernia exists. It should be managed through a multidisciplinary approach to ensure consistent standards and outcomes are achieved
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