307 research outputs found
On some Graphs with a Unique Perfect Matching
We show that deciding whether a given graph of size has a unique
perfect matching as well as finding that matching, if it exists, can be done in
time if is either a cograph, or a split graph, or an interval graph,
or claw-free. Furthermore, we provide a constructive characterization of the
claw-free graphs with a unique perfect matching
How to Measure Subdiffusion Parameters
We propose a method to measure the subdiffusion parameter and
subdiffusion coefficient which are defined by means of the
relation where
denotes a mean square displacement of a random walker starting from at
the initial time . The method exploits a membrane system where a substance
of interest is transported in a solvent from one vessel to another across a
thin membrane which plays here only an auxiliary role. We experimentally study
a diffusion of glucose and sucrose in a gel solvent, and we precisely determine
the parameters and , using a fully analytic solution of
the fractional subdiffusion equation.Comment: short version of cond-mat/0309072, to appear in Phys. Rev. Let
A quality improvement programme in radiotherapy using workflow audits
Background. Evaluation of the quality of healthcare depends on measures of structures, processes and outcomes. Progress in recording data allows for better measures of processes, such as the completeness of clinical data, the performance of professional tasks and the use of checklists.Objectives. To report the results of a radiotherapy (RT) workflow audit and a subsequent online survey of user experience.Methods. The RT workflow audit was developed in 2016 and has been undertaken twice a year at 28 facilities or units, with a total of 32 linear accelerators. Electronic patient folders were reviewed to assess the documentation of 90 task items, of which 64 were scored. The auditor came from another facility. The online survey took place in July 2020. It contained questions on the audit’s process, professional value and future use. Invitations were sent by email to the 151 radiotherapist staff at the 28 units where the audit had been implemented. Responses were anonymous.Results. For the RT workflow audit, scores improved from 60% in some units in 2016 to >90% in all units for at least 2 years since 2018. The number of responders to the online survey was 58, giving a responder rate of 38%. The margin of error of the results was 10%. The audit’s task items were considered appropriate by 77% of responders, and feedback was reported by 78% of them. The audit was considered very or extremely valuable to their unit’s service delivery by 58% of responders. Changes in the unit as a result of the audit were reported by 77% of responders. The audit was very useful or extremely useful to 75% of responders in maintaining personal professional standards. The proportion of responders who were very or extremely supportive of continuing with the audit was 77%. The comments in the online survey will be helpful for ongoing review of the RT workflow audit.Conclusions. The RT workflow audit extends the scope of accreditation audits by including measures of processes. Users of the audit evaluate its processes favourably and report that it has value both in their unit’s clinical service and for their personal professional standards. The audit is effective in developing quality improvement programmes
Measuring subdiffusion parameters
We propose a method to extract from experimental data the subdiffusion
parameter and subdiffusion coefficient which are defined by
means of the relation where
denotes a mean square displacement of a random walker starting from
at the initial time . The method exploits a membrane system where a
substance of interest is transported in a solvent from one vessel to another
across a thin membrane which plays here only an auxiliary role. Using such a
system, we experimentally study a diffusion of glucose and sucrose in a gel
solvent. We find a fully analytic solution of the fractional subdiffusion
equation with the initial and boundary conditions representing the system under
study. Confronting the experimental data with the derived formulas, we show a
subdiffusive character of the sugar transport in gel solvent. We precisely
determine the parameter , which is smaller than 1, and the subdiffusion
coefficient .Comment: 17 pages, 9 figures, revised, to appear in Phys. Rev.
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