1,721,514 research outputs found
Comparing cost-utility estimates: does the choice of EQ-5D or SF-6D matter?
No full textBACKGROUND: A number of different measures can be used within cost-utility analyses, we compared results according to both the EQ-5D and SF-6D. METHODS: A randomized trial was conducted to compare 4 options for people with knee pain. Over the 2 year trial period, the change in cost to health-service was estimated, and both the EQ-5D and SF-6D were used to estimate the change in quality-adjusted life years (QALYs). Using a complete case analysis, the cost-utility (incremental cost-effectiveness ratio [ICER]) of each option, according to both the EQ-5D and SF-6D, was calculated and assessed in relation to the cost-effectiveness threshold of pound20,000 per QALY. RESULTS: Of the 389 participants, 247 had complete cost, EQ-5D and SF-6D data. According to the EQ-5D, option 1 had an estimated ICER of pound10,815 (compared with option 4), option 2 was dominated by option 1, and option 3 was subject to extended dominance. Conversely, according to the SF-6D, option 3 had an ICER of pound9999 (compared with option 4), option 2 had an ICER of pound36,883 (compared with option 3), and option 1 was subject to extended dominance. CONCLUSION: The EQ-5D and SF-6D estimated that different options (1 and 3, respectively) were cost-effective at the pound20,000 per QALY threshold, demonstrating that the choice of measure does matter
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Comparing the performance of the EQ-5D and SF-6D when measuring the benefits of alleviating knee pain
No full textObective: to assess the practicality, validity and responsiveness of using each of two utility measures (the EQ-5D and SF-6D) to measure the benefits of alleviating knee pain.Methods: participants in a randomised controlled trial, which was designed to compare four different interventions for people with self-reported knee pain, were asked to complete the EQ-5D, SF-6D, and Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) at both pre- and post-intervention. For both utility measures, we assessed their practicality (completion rate), construct validity (ability to discriminate between baseline WOMAC severity levels), and responsiveness (ability to discriminate between three groups: those whose total WOMAC score, i) did not improve, ii) improved by <20%, and iii) improved by > or = 20%).Results: the EQ-5D was completed by 97.7% of the 389 participants, compared to 93.3% for the SF-6D. Both the EQ-5D and SF-6D were able to discriminate between participants with different levels of WOMAC severity (p < 0.001). The mean EQ-5D change was -0.036 for group i), 0.091 for group ii), and 0.127 for group iii), compared to 0.021, 0.023 and 0.053 on the SF-6D. These change scores were significantly different according to the EQ-5D (p < 0.001), but not the SF-6D.Conclusion: the EQ-5D and SF-6D had largely comparable practicality and construct validity. However, in contrast to the EQ-5D, the SF-6D could not discriminate between those who improved post-intervention, and those who did not. This suggests that it is more appropriate to use the EQ-5D in future cost-effectiveness analyses of interventions which are designed to alleviate knee pain.</p
Stabilization of vinylic intermediates in the addition, cyclization, and oligomerization reactions of alkynes by coordination of molybdenum and tungsten. The crystal and molecular structure of [W(SC6H4Me-p)[η2-C(CF3)C(CF3)PEt3] (η2-CF3C≡CCF3)(η-C5H5)] and [WCl[η2-C(CF3)C(CF3)CN](η2-CF3C≡CCF3)(η-C5H5)]
No full textNucleophilic attack of phosphines, phosphites or Me3CNC on the η2-CF3C≡CCF3 (L) complexes L2WBr2(CO) and L2MX(Cp) (Cp = η5-cyclopentadienyl; M = Mo, W, X = Cl, SC6F5; M = W, X = SC6H4Me-p) occurs at an acetylenic C atom to give 1:1 adducts. The products, I [X = SC6H4Me-p, L1 = PEt3 (II); X = Cl, L1 = Me3CNC (III)] were shown by x-ray diffraction to contain a metal-stabilized 1-3 dipolar vinyl ligand L+C(CF3)C-(CF3) η2-coordinated to the W center. The structures of II and III were refined to R 0.038, 0.040, for 2924, 6900 independent reflections, resp
Synthesis and reactions of tungsten(II) norbornadiene (nbd) complexes. The crystal and molecular structure of [WBr(SC6F5)(CO)2(nbd)]
No full textThe reaction of [WBr2(CO)2(nbd)] 1 (nbd = norbornadiene) with Tl(C5H5) gave a monocarbonyl deriv. [WBr(CO)(nbd)(η5-C5H5)] 2. With Tl(O2CMe) and Tl[O(S)CMe], complex 1 gave monosubstituted derivs. [WBr(O2CMe)(CO)2(nbd)] 3a and [WBr{O(S)CMe}(CO)2(nbd)] 3b which appear to be seven-coordinate according to IR data. In contrast 1 and Tl(SC6F5) (1:1 molar ratio) gave the six-coordinate complex [WBr(SC6F5)(CO)2(nbd)] 4. An x-ray diffraction study of 4 established that it has a distorted-octahedral structure with trans W-CO bonds approx. perpendicular to a plane contg. the W, Br and S atoms and the midpoints of the nbd C:C bonds. Simple electronic arguments provide a rationalization of many of the structural features of 4. Reaction of 1 with 2 molar equivalents of Tl(SC6F5) gave the bis(thiolate) deriv. [W(SC6F5)(CO)2(nbd)] 5 again with a trans arrangement of CO ligands. The reactions of 5 with L = PEt3, PMe2Ph or P(OMe)3 gave the six-coordinate complexes [W(SC6F5)2(CO)2L2] 6 which exist in two isomeric forms, red or green. Dynamic NMR studies have been used to characterize the isomeric behavior and fluxional processes in the complexes
Synthesis and reactions of the coordinatively unsaturated hexafluorobut-2-yne complex [WBr2(CO)(CF3C≡CCF3)2]. The crystal and molecular structure of di-μ-bromobis{carbonyl[3-(diethoxyphosphoryl)hexafluorobut-2-en-2-yl](η-hexafluorobut-2-yne)tungsten}
No full textReaction of [{WBr2(CO)4}2] with CF3C≡CCF3 in pentane affords the bis(alkyne) complex [WBr2(CO)(CF3C≡CCF3)2] (I) in which the carbonyl ligand appears to function as a σ-donor ligand only, according to IR data. I reacts with P(OMe)3 and P(OEt)3 to give dimeric complexes II (R = Me, Et) contg. a novel vinylphosphonate ligand resulting from a Michaelis-Arbuzov type elimination of alkyl bromide. The structure of the complex with R = Et has been detd. by x-ray anal. The tungsten coordination is octahedral with mutually cis carbonyl and σ-alkenyl carbon atoms both trans to μ-Br groups, and with phosphate O trans to a four-electron donor η2-CF3C≡CCF3. The bonding in the novel vinyl phosphonate W[C(CF3):C(CF3)P(OEt)2O] chelate ring is discussed
Do estimates of cost-utility based on the EQ-5D differ from those based on the mapping of utility scores?
No full textBackground: mapping has been used to convert scores from condition-specific measures into utility scores, and to produce estimates of cost-effectiveness. We sought to compare the QALY gains, and incremental cost per QALY estimates, predicted on the basis of mapping to those based on actual EQ-5D scores.Methods: in order to compare 4 different interventions 389 individuals were asked to complete both the EQ-5D and the Western Ontartio and McMaster Universities Osteoarthritis Index (WOMAC) at baseline, 6, 12, and 24 months post-intervention. Using baseline data various mapping models were developed, where WOMAC scores were used to predict the EQ-5D scores. The performance of these models was tested by predicting the EQ-5D post-intervention scores. The preferred model (that with the lowest mean absolute error (MAE)) was used to predict the EQ-5D scores, at all time points, for individuals who had complete WOMAC and EQ-5D data. The mean QALY gain associated with each intervention was calculated, using both actual and predicted EQ-5D scores. These QALY gains, along with previously estimated changes in cost, were also used to estimate the actual and predicted incremental cost per QALY associated with each of the four interventions.Results: the EQ-5D and the WOMAC were completed at baseline by 348 individuals, and at all time points by 259 individuals. The MAE in the preferred model was 0.129, and the mean QALY gains for each of the four interventions was predicted to be 0.006, 0.058, 0.058, and 0.136 respectively, compared to the actual mean QALY gains of 0.087, 0.081, 0.120, and 0.149. The most effective intervention was estimated to be associated with an incremental cost per QALY of pound6,068, according to our preferred model, compared to pound13,154 when actual data was used.Conclusion: we found that actual QALY gains, and incremental cost per QALY estimates, differed from those predicted on the basis of mapping. This suggests that though mapping may be of value in predicting the cost-effectiveness of interventions which have not been evaluated using a utility measure, future studies should be encouraged to include a method of actual utility measurement.Trial registration: current Controlled Trials ISRCTN93206785.</p
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