1,720,968 research outputs found
Calcium and Phosphate Control by Dialysis Treatments
No full textCalcium and phosphate changes, besides their involvement in bone disease, have been claimed to also be involved in the increased vascular morbidity and mortality of dialysis patients. Even after the recent advances of therapeutic options, their control still remains a challenging problem. Dialysis treatment is a basic approach to the control of these two electrolytes. Calcium control by dialysis is mainly dependent on its mass balance, which is variably influenced by the calcium concentration difference between blood and dialysis solutions (either dialysate or infusion fluids) and by the duration of the treatment. There is no full agreement on the ideal calcium concentration in dialysis fluids, since this choice is also mostly influenced by the concomitant medical therapy. However, there is some consensus in suggesting a lower calcium concentration in standard hemodialysis (HD) treatment (1.25-1.50 mmol/l) than in dialysis treatments characterized by high convective transport. In peritoneal dialysis, calcium balance is affected by its blood dialysate concentration difference and dialysate glucose concentration, with ideal calcium concentration probably being >1.25 and <1.75 (which are the most commonly used concentrations). Phosphate dialysis balance is also a critical and challenging problem, since the possibility to reach an always desired null or possibly negative balance relies on this. Even though some increased phosphate removal can be obtained with the highest efficiency techniques, such as hemodiafiltration as compared with traditional HD, the most impacting factor still remains the duration of dialysis treatment. However, some experimental attempts at increasing phosphate removal independently of increasing dialysis duration are mentioned
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
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
Immediate graft function positively affects long-term outcome of renal allografts from older but not from younger donors
No full textThere is disagreement about the impact of delayed graft function (DGF) on renal allograft outcome. This may depend on several variables including the age of the donor. We evaluated whether DGF could have different effects in recipients of kidneys from donors aged more than 60 years versus well-matched recipients of younger kidney donors. Patients were retrospectively subdivided into 3 groups. Immediate graft function (IGF), DGF without dialysis (DGF-ND), DGF requiring dialysis (DGF-D). DGF-ND and DGF-D occurred more frequently among 198 older than 198 younger donors (P = .016 and P = .044, respectively). The 5-year patient (96% vs 93%) and pure graft (96% vs 89%) survivals were significantly better in younger recipients, while the incidence of acute rejection was similar. After a mean follow-up of 66 ± 44 months in older donor recipients, the graft survival was significantly better among IGF than patients in the DGF-ND (P = .046) or DGF-D (P = .003) groups. Instead, in younger recipients there was no difference in graft survival between IGD and DGF-ND. Only patients with DGF-D showed a significantly worse outcome. Upon multivariate analysis of older donors, their recipients, showed the pattern of graft function recovery to be the only variable associated with allograft outcome. Instead in younger donor recipients, acute rejection and time on dialysis were the main variables associated with a poor outcome. In older donor recipients, DGF was an independent variable associated with a poor graft outcome. In younger donor recipients, duration of dialysis and rejection were the most important predictors of poor graft outcomes
Clinical validation of glucose pump test (GPT) compared with ultrasound dilution technology in arteriovenous graft surveillance
No full textBackground. Blood flow (Qa) measurements are an important step in the surveillance protocol of haemodialysis vascular access (VA). The glucose pump test (GPT) is a new test for Qa measurement based on the dilution of a constant glucose infusion. The aim of this study is to verify the clinical accuracy of GPT in a graft surveillance protocol with sequential Qa measurements. Methods. In 30 chronic haemodialysis patients with graft, we compared monthly sequential Qa measurements performed with GPT in pre-dialysis and the ultrasound dilution technique (HD01 device Transonic Systems Inc., USA) during dialysis. The colour Doppler ultrasonography study (CDU) was our reference standard for the diagnosis of stenosis. The endpoints were the graft thrombosis or PTA treatment. Results. According to the K/DOQI guidelines we could identify the thrombosis high-risk grafts when Qa was 25% in serial Qa measurements. HD01 yielded 27 of 112 high-risk Qa measurements (21 Qa 25%; mean 43 ± 7%). In 12 of 27 cases the CDU control did not show haemodynamically significant stenoses (false positive); 15 of 27 cases were confirmed high-risk accesses by CDU and did PTAs (HD01 specificity 86%). GPT yielded 14 of 112 high-risk Qa measurements (8 Qa 25%; mean 38 ± 8%) and all had severe stenoses and underwent PTA treatments showing a GPT specificity of 100%. The CDU study allowed us to correctly assess the Qa negative cases. HD01 method had 10 false negative cases (treated or clotted grafts with a Qa >600ml/min and Δ Qa <25%) with a sensitivity of 60%, while GPT had 11 false negative cases with a sensitivity of 56%. The diagnostic accuracy tested with the ROC curves was similar with both tests (area under the curve was 0.762 and 0.752 with GPT and ultrasound dilution, respectively; P=0.985). The diagnostic efficiency (percentage of grafts with agreement between test result and factual situation) was 90 and 80% (P=0.056) for GPT and HD01, respectively. Conclusion. Compared with HD01, the GPT had a lower false positive rate and similar diagnostic accuracy and efficiency. The clinical implication is a smaller number of unnecessary, invasive procedures (angiographies or PTAs), without increasing the thrombosis risk. This study has shown that GPT is an accurate, quick and economic test for Qa monitoring
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