500 research outputs found
Some legal conclusions concerning accepted accounting principles as determined by decisions of the United States Supreme court and the United States Board of tax appeals,
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Holonomy and parallel transport for Abelian gerbes
In this paper we establish a one-to-one correspondence between -gerbes
with connections, on the one hand, and their holonomies, for simply connected
manifolds, or their parallel transports, in the general case, on the other
hand. This result is a higher-order analogue of the familiar equivalence
between bundles with connections and their holonomies for connected manifolds.
The holonomy of a gerbe with group on a simply connected manifold is
a group morphism from the thin second homotopy group to , satisfying a
smoothness condition, where a homotopy between maps from to is
thin when its derivative is of rank . For the non-simply connected
case, holonomy is replaced by a parallel transport functor between two monoidal
Lie groupoids. The reconstruction of the gerbe and connection from its holonomy
is carried out in detail for the simply connected case. Our approach to abelian
gerbes with connections holds out prospects for generalizing to the non-abelian
case via the theory of double Lie groupoids.Comment: Final version. Improved readibility (hopefully). LaTeX, 60 pages, 14
figures. To appear in Advances in Mathematic
Modeling Constellation Virtual Missions Using the Vdot(Trademark) Process Management Tool
The authors have identified a software tool suite that will support NASA's Virtual Mission (VM) effort. This is accomplished by transforming a spreadsheet database of mission events, task inputs and outputs, timelines, and organizations into process visualization tools and a Vdot process management model that includes embedded analysis software as well as requirements and information related to data manipulation and transfer. This paper describes the progress to date, and the application of the Virtual Mission to not only Constellation but to other architectures, and the pertinence to other aerospace applications. Vdot s intuitive visual interface brings VMs to life by turning static, paper-based processes into active, electronic processes that can be deployed, executed, managed, verified, and continuously improved. A VM can be executed using a computer-based, human-in-the-loop, real-time format, under the direction and control of the NASA VM Manager. Engineers in the various disciplines will not have to be Vdot-proficient but rather can fill out on-line, Excel-type databases with the mission information discussed above. The author s tool suite converts this database into several process visualization tools for review and into Microsoft Project, which can be imported directly into Vdot. Many tools can be embedded directly into Vdot, and when the necessary data/information is received from a preceding task, the analysis can be initiated automatically. Other NASA analysis tools are too complex for this process but Vdot automatically notifies the tool user that the data has been received and analysis can begin. The VM can be simulated from end-to-end using the author s tool suite. The planned approach for the Vdot-based process simulation is to generate the process model from a database; other advantages of this semi-automated approach are the participants can be geographically remote and after refining the process models via the human-in-the-loop simulation, the system can evolve into a process management server for the actual process
The importance of unique populations for conservation: the case of the Great Ormeās Head grayling butterfly Hipparchia semele (Linnaeus, 1758) (Lepidoptera: Satyrinae)
Small populations with unusual characteristics subject to extreme conditions provide opportunities for exploring adaptability in the face of environmental changes. Two sets of data have been examined to determine how unusual is the population of Hipparchia semele on the Great Ormeās Head, North Wales, compared with other sites in the UK. The population on the Great Orme is shown to have unique features, including significantly reduced wing expanse and wing ocellation and extreme flight period characteristics. Analyses of flight period data from the UK Butterfly Monitoring Scheme (UKBMS) using over a 100 sites reveals that, although the Great Orme population is one of a number of sites from the Channel Islands to northern Scotland with an early mean flight period, it has by far the earliest flight period and longest flight period of all populationsāthe latter raising the mean flight period date. Furthermore the unique characteristics of H. semele on the Orme may well be underestimated, inasmuch as sampling of individuals for the phenotype study is incomplete, including only the area along the North Wales coast into Cheshire, while the UKBMS transect is restricted to the south-west portion of the headland. Unique populations are often accorded focused conservation effort; especially potential flagship species in decline as in the case of British H. semele. As the Great Orme population presents a rare opportunity for studying adaptations in an extreme local environment, particularly considering current projections for climate changes, we advocate further research and attention being given to this unusual population
Usability, Acceptability, and Effectiveness of Web-Based Conversational Agents to Facilitate Problem Solving in Older Adults: Controlled Study.
BACKGROUND: The usability and effectiveness of conversational agents (chatbots) that deliver psychological therapies is under-researched. OBJECTIVE: This study aimed to compare the system usability, acceptability, and effectiveness in older adults of 2 Web-based conversational agents that differ in theoretical orientation and approach. METHODS: In a randomized study, 112 older adults were allocated to 1 of the following 2 fully automated interventions: Manage Your Life Online (MYLO; ie, a chatbot that mimics a therapist using a method of levels approach) and ELIZA (a chatbot that mimics a therapist using a humanistic counseling approach). The primary outcome was problem distress and resolution, with secondary outcome measures of system usability and clinical outcome. RESULTS: MYLO participants spent significantly longer interacting with the conversational agent. Posthoc tests indicated that MYLO participants had significantly lower problem distress at follow-up. There were no differences between MYLO and ELIZA in terms of problem resolution. MYLO was rated as significantly more helpful and likely to be used again. System usability of both the conversational agents was associated with helpfulness of the agents and the willingness of the participants to reuse. Adherence was high. A total of 12% (7/59) of the MYLO group did not carry out their conversation with the chatbot. CONCLUSIONS: Controlled studies of chatbots need to be conducted in clinical populations across different age groups. The potential integration of chatbots into psychological care in routine services is discussed
Microwave Signatures of Melting/Refreezing Snow: Observations and Modeling Using Dense Medium Radiative Transfer Theory
Microwave brightness temperatures of snow covered terrains can be modeled by means of the Dense Radiative Transfer Medium Theory (DMRT). In a dense medium, such as snow, the assumption of independent scattering is no longer valid and the scattering of correlated scatterers must be considered. In the DMRT, this is done considering a pair distribution function of the particles position. In the electromagnetic model, the snowpack is simulated as a homogeneous layer having effective permittivity and albedo calculated through the DMRT. In order to account for clustering of snow crystals, a model of cohesive particles can be applied, where the cohesion between the particles is described by means of a dimensionless parameters called stickiness (z), representing a measure of the inversion of the attraction of the particles. The lower the z the higher the stickiness. In this study, microwave signatures of melting and refreezing cycles of seasonal snowpacks at high altitudes are studied by means of both experimental and modeling tools. Radiometric data were collected 24 hours per day by the University of Michigan Tower Mounted Radiometer System (TMRS). The brightness temperatures collected by means of the TMRS are simulated by means of a multi-layer electromagnetic model based on the dense medium theory with the inputs to the model derived from the data collected at the snow pits and from the meteorological station. The paper is structured as follows: in the first Section the temperature profiles recorded by the meteorological station and the snow pit data are presented and analyzed; in the second Section, the characteristics of the radiometric system used to collect the brightness temperatures are reported together with the temporal behavior of the recorded brightness temperatures; in the successive Section the multi-layer DMRT-based electromagnetic model is described; in the fourth Section the comparison between modeled and measured brightness temperatures is discussed. We dedicate the last Section to the conclusions and future works
Utility of the new Movement Disorder Society clinical diagnostic criteria for Parkinson's disease applied retrospectively in a large cohort study of recent onset cases
Objective:
To examine the utility of the new Movement Disorder Society (MDS) diagnostic criteria in a large cohort of Parkinson's disease (PD) patients.
Methods:
Recently diagnosed (<3.5 years) PD cases fulfilling United Kingdom (UK) brain bank criteria in Tracking Parkinson's, a UK multicenter prospective natural history study were assessed by retrospective application of the MDS criteria.
Results:
In 2000 cases, 1835 (91.7%) met MDS criteria for PD, either clinically established (n = 1261, 63.1%) or clinically probable (n = 574, 28.7%), leaving 165 (8.3%) not fulfilling criteria. Clinically established cases were significantly more likely to have limb rest tremor (89.3%), a good l-dopa response (79.5%), and olfactory loss (71.1%), than clinically probable cases (60.6%, 44.4%, and 34.5% respectively), but differences between probable PD and ānot PDā cases were less evident. In cases not fulfilling criteria, the mean MDS UPDRS3 score (25.1, SD 13.2) was significantly higher than in probable PD (22.3, SD 12.7, p = 0.016) but not established PD (22.9, SD 12.0, p = 0.066). The l-dopa equivalent daily dose of 341 mg (SD 261) in non-PD cases was significantly higher than in probable PD (250 mg, SD 214, p < 0.001) and established PD (308 mg, SD 199, p = 0.025). After 30 months' follow-up, 89.5% of clinically established cases at baseline remained as PD (established/probable), and 86.9% of those categorized as clinically probable at baseline remained as PD (established/probable). Cases not fulfilling PD criteria had more severe parkinsonism, in particular relating to postural instability, gait problems, and cognitive impairment.
Conclusion:
Over 90% of cases clinically diagnosed as early PD fulfilled the MDS criteria for PD. Those not fulfilling criteria may have an atypical parkinsonian disorder or secondary parkinsonism that is not correctly identified by the UK Brain Bank criteria, but possibly by the new criteria
Acceptability and Effectiveness of NHS-Recommended e-Therapies for Depression, Anxiety, and Stress: Meta-Analysis.
BACKGROUND: There is a disconnect between the ability to swiftly develop e-therapies for the treatment of depression, anxiety, and stress, and the scrupulous evaluation of their clinical utility. This creates a risk that the e-therapies routinely provided within publicly funded psychological health care have evaded appropriate rigorous evaluation in their development. OBJECTIVE: This study aims to conduct a meta-analytic review of the gold standard evidence of the acceptability and clinical effectiveness of e-therapies recommended for use in the National Health Service (NHS) in the United Kingdom. METHODS: Systematic searches identified appropriate randomized controlled trials (RCTs). Depression, anxiety, and stress outcomes at the end of treatment and follow-up were synthesized using a random-effects meta-analysis. The grading of recommendations assessment, development, and evaluation approach was used to assess the quality of each meta-analytic comparison. Moderators of treatment effect were examined using subgroup and meta-regression analysis. Dropout rates for e-therapies (as a proxy for acceptability) were compared against controls. RESULTS: A total of 24 studies evaluating 7 of 48 NHS-recommended e-therapies were qualitatively and quantitatively synthesized. Depression, anxiety, and stress outcomes for e-therapies were superior to controls (depression: standardized mean difference [SMD] 0.38, 95% CI 0.24 to 0.52, N=7075; anxiety and stress: SMD 0.43, 95% CI 0.24 to 0.63, n=4863), and these small effects were maintained at follow-up. Average dropout rates for e-therapies (31%, SD 17.35) were significantly higher than those of controls (17%, SD 13.31). Limited moderators of the treatment effect were found. CONCLUSIONS: Many NHS-recommended e-therapies have not been through an RCT-style evaluation. The e-therapies that have been appropriately evaluated generate small but significant, durable, beneficial treatment effects. TRIAL REGISTRATION: International Prospective Register of Systematic Reviews (PROSPERO) registration CRD42019130184; https://www.crd.york.ac.uk/prospero/display_record.php?RecordID=130184
Vascular disease and vascular risk factors in relation to motor features and cognition in early Parkinson's disease
Funded by Parkinson's UK National Institute for Health Research (NIHR) DeNDRoN network NIHR Newcastle Biomedical Research Unit Newcastle University NIHR funded Biomedical Research Centre in CambridgePeer reviewedPublisher PD
Development and assessment of a bone scanning device to enhance restraint performance
The objective of the BOSCOS (BOne Scanning for Occupant Safety) project was the development of a system that can make an assessment of the bone characteristics of each vehicle occupant in order to estimate their skeletal strengths. The seatbelt and airbag characteristics can then be adjusted to deliver optimum levels of protection specifically for each occupant. A system introduced into every vehicle has the capacity to save lives and reduce injury levels across the whole spectrum of vehicle occupants. This paper describes the contributions from academic and industrial partners to this UK Department for Transport funded project.Commercial pressure focuses restraint design on meeting legal requirements for vehicle approval, but legal requirements use dummies which do not represent the range of car occupant shapes, sizes, and driving positions. A person with lower skeletal characteristics may not be able to withstand the current fixed levels of restraint without sustaining injuries. Conversely, a person with greater skeletal characteristics may be capable of withstanding greater levels of restraint.Possible technologies that are available have been assessed for their suitability for an in-vehicle monitoring system. Accident studies have been conducted to create a baseline of statistics in terms of casualties and their injuries. Initial bone scanning studies have utilised different types of equipment and a new prototype scanner has been developed for use in a vehicle environment using ultrasound technology.Computer based occupant mathematical modelling has been used to establish the potential gains from a working system and also the requirements needed of the restraint systems toachieve these gains. In addition, bone scanning has been conducted, to determine a method to read across from scan values to skeletal condition to provide data for the optimisation of the restraint system
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