8,901 research outputs found
Alternative determinism principle for topological analysis of chaos
The topological analysis of chaos based on a knot-theoretic characterization
of unstable periodic orbits has proved a powerful method, however knot theory
can only be applied to three-dimensional systems. Still, the core principles
upon which this approach is built, determinism and continuity, apply in any
dimension. We propose an alternative framework in which these principles are
enforced on triangulated surfaces rather than curves and show that in dimension
three our approach numerically predicts the correct topological entropies for
periodic orbits of the horseshoe map.Comment: Accepted for publication as Rapid Communication in Physical Review
Comparison of outcome measures for patients with chronic obstructive pulmonary disease (COPD) in an outpatient setting
BACKGROUND: To assist clinicians and researchers in choosing outcome measures for patients with chronic obstructive pulmonary disease attending routine outpatient clinics, a comparative assessment was undertaken of four questionnaires designed to reflect the patients' perception of their physical and emotional health in terms of their feasibility, validity, reliability, and responsiveness to health change. METHODS: Two condition specific questionnaires, the St George's Respiratory Questionnaire (SGRQ) and Guyatt's Chronic Respiratory Questionnaire (CRQ), and two generic questionnaires, the Short Form-36 Health Survey (SF-36) and Euroqol (EQ), were compared for their discriminative and evaluative properties. Spirometric tests and a walking test were also performed. One hundred and fifty six adults who were clinically judged to have COPD and who attended an outpatient chest clinic were assessed at recruitment and six and 12 months later. Patients were also asked whether their health had changed since their last assessment. RESULTS: Completion rates and consistency between items for dimensions of the SGRQ were lower than for dimensions of the other questionnaires. The distributions of responses were skewed for certain dimensions in all questionnaires except the CRQ. Validity was supported for all instruments insofar as patients' scores were associated with differences in disease severity. The generic questionnaires better reflected other health problems. All instruments were reliable over time. The condition specific questionnaires were more responsive between baseline and first follow up visit but this difference did not persist. While certain dimensions of the SF-36 were responsive to patient perceived changes, this did not apply to the derived single index of the EQ. The rating scale of the EQ, however, provided a quick and easy indicator of change. CONCLUSIONS: Evidence from this study supports the CRQ and the SF-36 as comprehensive outcome measures for patients with longstanding COPD
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Jojoba: An assessment of prospects
This report examines in detail the sperm oil and animal and vegetable wax markets in an attempt to establish market price and volume parameters for jojoba oil and wax. These market analyses suggest that at £900 to £950 per tonne jojoba wax could compete in the wax markets and might obtain a share of the market of between 2,000 and 5,000 tonnes. At £500 to £600 per tonne jojoba oil could compete with sperm oil which at present has a market of below 20,000 tonnes, although this will probably have been eroded to a substantial extent by synthetics by the time jojoba oil is available in quantities of this order. In particular, in this latter market jojoba oil might be used by the leather, lubricants and pharmaceutical industries. If, for illustrative purposes, a 25,000 tonne market were to be secured and a future yield of 2.5 tonnes per hectare of oil obtained, a cultivated area of 10,000 hectares of jojoba would suffice. This is a very small area in global terms and it seems, therefore, that jojoba is unlikely to provide more than a minor new source of income for a few developing countries. Jojoba must be considered as one of a number of possible plant introductions to arid zones and the need is to direct attention to research priorities which aim at overcoming limitations in the cultivation of the crop. If research proves that jojoba can be cultivated satisfactorily it would be reasonable to organize trial plots in selected developing countries to obtain more basic agronomic information on how the plant reacts in different environments. Only when these trials have proved successful and realistic yield data obtained, will the necessary information·be available to enable the economic potential for the introduction of jojoba to developing countries to be examined fully
Chains of infinite order, chains with memory of variable length, and maps of the interval
We show how to construct a topological Markov map of the interval whose
invariant probability measure is the stationary law of a given stochastic chain
of infinite order. In particular we caracterize the maps corresponding to
stochastic chains with memory of variable length. The problem treated here is
the converse of the classical construction of the Gibbs formalism for Markov
expanding maps of the interval
Dose-adapted post-transplant cyclophosphamide for HLA-haploidentical transplantation in Fanconi anemia.
We developed a haploidentical transplantation protocol with post-transplant cyclophosphamide (CY) for in vivo T-cell depletion (TCD) using a novel adapted-dosing schedule (25 mg/kg on days +3 and +4) for Fanconi anemia (FA). With median follow-up of 3 years (range, 37 days to 6.2 years), all six patients engrafted. Two patients with multiple pre-transplant comorbidities died, one from sepsis and one from sepsis with associated chronic GVHD. Four patients without preexisting comorbidities and early transplant referrals are alive with 100% donor chimerism and excellent performance status. We conclude that adjusted-dosing post-transplant CY is effective in in vivo TCD to promote full donor engraftment in patients with FA
A ‘criminal personas’ approach to countering criminal creativity
This paper describes a pilot study of a ‘criminal personas’ approach to countering criminal creativity. The value of the personas approach has been assessed by comparing the identification of criminal opportunity, through ‘traditional’ brainstorming and then through ‘criminal personas’ brainstorming The method involved brainstorm sessions with Computer Forensics Practitioners and with Product Designers, where they were required to generate criminal scenarios, select the most serious criminal opportunities, and propose means of countering them. The findings indicated that there was merit in further research in the development and application of the ‘criminal personas’ approach. The generation of criminal opportunity ideas and proposal of counter criminal solutions were both greater when the brainstorm approach involved the group responding through their given criminal personas
A detailed study of the photo-injection annealing of thermally diffused InP solar cells
A detailed analysis of the annealing of thermally diffused InP solar cells fabricated by the Nippon Mining Co. is presented. The cells were irradiated with 1 MeV electrons, and the induced degradation is measured using deep level transient spectroscopy and low temperature (86 K) IV measurements. Clear recovery of the photovoltaic parameters is observed during low temperature (T is less than 300 K) solar illuminations (1 sun, AMO) with further recovery at higher temperatures (300 less than T less than 500 K). For example, the output of a cell which was irradiated up to a fluence of 1 x 10(exp 16) cm(sup -2) was observed to recover to within 5 percent of the pre-irradiation output. An apparent correlation between the recovery of I(sub sc) and the annealing of the H4 defect and of the minority carrier trapping centers is observed. An apparent correlation between the recovery of VO, and the annealing of the H5 defect is also observed. These apparent correlations are used to develop a possible model for the mechanism of the recovery of the solar cells
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