169 research outputs found
SS Ari: a shallow-contact close binary system
Two CCD epochs of light minimum and a complete R light curve of SS Ari are
presented. The light curve obtained in 2007 was analyzed with the 2003 version
of the W-D code. It is shown that SS Ari is a shallow contact binary system
with a mass ratio and a degree of contact factor f=9.4(\pm0.8%). A
period investigation based on all available data shows that there may exist two
distinct solutions about the assumed third body. One, assuming eccentric orbit
of the third body and constant orbital period of the eclipsing pair results in
a massive third body with and P_3=87.00.278M_{\odot}$. Both of the cases
suggest the presence of an unseen third component in the system.Comment: 28 pages, 9 figures and 5 table
Reviews may overestimate the effectiveness of medicines for back pain: Systematic review and meta-analysis
Objective: Systematic-reviews of analgesics for low back pain generally include published data only. Obtaining data from unpublished trials is potentially important because they may impact effect sizes in meta-analyses. We determined whether including unpublished data from trial registries changes the effect sizes in meta-analyses of analgesics for low back pain.
Study Design and Setting: Trial registries were searched for unpublished data that conformed to the inclusion criteria of n=5 individual source systematic-reviews. We reproduced the meta-analyses using data available from the original reviews then re-ran the same analyses with the addition of new unpublished data.
Results: Sixteen completed, unpublished, trials were eligible for inclusion in four of the source reviews. Data were available for five trials. We updated the analyses for two of the source reviews. The addition of data from two trials reduced the effect size of muscle relaxants, compared to sham, for recent-onset low back pain from -21.71 (95%CI -28.23 to -15.19) to -2.34 (95%CI -3.34 to -1.34) on a 0-100 scale for pain intensity. The addition of data from three trials (one enriched design) reduced the effect size of opioid analgesics, compared to sham, for chronic low back pain from -10.10 (95%CI -12.81 to -7.39) to -9.31 (95%CI -11.51 to -7.11). The effect reduced in the subgroup of enriched design studies, from -12.40 (95%CI -16.90 to -7.91) to 11.34 (95%CI -15.36 to -7.32), and in the subgroup of non-enriched design studies; from -7.27 (95%CI -9.97 to -4.57) to -7.19 (95%CI -9.24 to -5.14).
Conclusion: Systematic-reviews should include reports of unpublished trials. The result for muscle relaxants conflicts with the conclusion of the published review and recent international guidelines. Adding unpublished data strengthens the evidence that opioid analgesics have small effects on persistent low back pain and more clearly suggests these effects may not be clinically meaningful
Systematic reviews that include only published data may overestimate the effectiveness of analgesic medicines for low back pain: A systematic review and meta-analysis
Objective: Systematic reviews of analgesics for low back pain generally include published data only. Obtaining data from unpublished trials is potentially important because they may impact effect sizes in meta-analyses. We determined whether including unpublished data from trial registries changes the effect sizes in meta-analyses of analgesics for low back pain.
Study Design and Setting: Trial registries were searched for unpublished data that conformed to the inclusion criteria of n = 5 individual source systematic reviews. We reproduced the meta-analyses using data available from the original reviews and then reran the same analyses with the addition of new unpublished data.
Results: Sixteen completed, unpublished, trials were eligible for inclusion in four of the source reviews. Data were available for five trials. We updated the analyses for two of the source reviews. The addition of data from two trials reduced the effect size of muscle relaxants, compared with sham, for recent-onset low back pain from −21.71 (95% CI: −28.23 to −15.19) to −2.34 (95% CI: −3.34 to −1.34) on a 0–100 scale for pain intensity. The addition of data from three trials (one enriched design) reduced the effect size of opioid analgesics, compared with sham, for chronic low back pain from −10.10 (95% CI: −12.81 to −7.39) to −9.31 (95% CI: −11.51 to −7.11). The effect reduced in the subgroup of enriched design studies, from −12.40 (95% CI: −16.90 to −7.91) to −11.34 (95% CI: −15.36 to −7.32), and in the subgroup of nonenriched design studies, from −7.27 (95% CI: −9.97 to −4.57) to −7.19 (95% CI: −9.24 to −5.14).
Conclusion: Systematic reviews should include reports of unpublished trials. The result for muscle relaxants conflicts with the conclusion of the published review and recent international guidelines. Adding unpublished data strengthens the evidence that opioid analgesics have small effects on persistent low back pain and more clearly suggests these effects may not be clinically meaningful
Absolute properties of the binary system BB Pegasi
We present a ground based photometry of the low-temperature contact binary BB
Peg. We collected all times of mid-eclipses available in literature and
combined them with those obtained in this study. Analyses of the data indicate
a period increase of 3.0(1) x 10^{-8} days/yr. This period increase of BB Peg
can be interpreted in terms of the mass transfer 2.4 x 10^{-8} Ms yr^{-1} from
the less massive to the more massive component. The physical parameters have
been determined as Mc = 1.42 Ms, Mh = 0.53 Ms, Rc = 1.29 Rs, Rh = 0.83 Rs, Lc =
1.86 Ls, and Lh = 0.94 Ls through simultaneous solution of light and of the
radial velocity curves. The orbital parameters of the third body, that orbits
the contact system in an eccentric orbit, were obtained from the period
variation analysis. The system is compared to the similar binaries in the
Hertzsprung-Russell and Mass-Radius diagram.Comment: 17 pages, 3 figures, accepted for Astronomical Journa
The RESOLVE Trial for people with chronic low back pain: Statistical analysis plan
Background: Statistical analysis plans describe the planned data management and analysis for clinical trials. This supports transparent reporting and interpretation of clinical trial results. This paper reports the statistical analysis plan for the RESOLVE clinical trial. The RESOLVE trial assigned participants with chronic low back pain to graded sensory-motor precision training or sham-control.
Results: We report the planned data management and analysis for the primary and secondary outcomes. The primary outcome is pain intensity at 18-weeks post randomization. We will use mixed-effects models to analyze the primary and secondary outcomes by intention-to-treat. We will report adverse effects in full. We also describe analyses if there is non-adherence to the interventions, data management procedures, and our planned reporting of results. Conclusion: This statistical analysis plan will minimize the potential for bias in the analysis and reporting of results from the RESOLVE trial.
Trial registration: ACTRN12615000610538 (https://www.anzctr.org.au/Trial/Registration/ TrialReview.aspx?id=368619).
© 2020 Associac¸ao˜ Brasileira de Pesquisa e Pos-Graduac ´ ¸ao˜ em Fisioterapia. Published by Elsevier Editora Ltda. All rights reserved
Paracetamol, NSAIDS and opioid analgesics for chronic low back pain: A network meta-analysis (Protocol)
This is a protocol for a Cochrane Review (Intervention). The objectives are as follows:
To answer the clinical question: ‘what analgesic medicine shall I prescribe this patient with chronic low back pain to reduce their pain?’.
The objectives are to determine the analgesic effects, safety, effect on function, and relative rank according to analgesic effect, safety and effect on function of a single course of opioid analgesics, NSAIDs or paracetamol or combinations of these medicines
Restriction enzyme-free mutagenesis via the light regulation of DNA polymerization
The effects of photocaged nucleosides on the DNA polymerization reaction was investigated, finding that most polymerases are unable to recognize and read through the presence of a single caging group on the DNA template. Based on this discovery, a new method of introducing mutations into plasmid DNA via a light-mediated mutagenesis protocol was developed. This methodology is advantageous over several common approaches in that it requires the use of only two polymerase chain reaction primers, and does not require any restriction sites or use of restriction enzymes. Additionally, this approach enables not only site-directed mutations, but also the insertion of DNA strands of any length into plasmids and the deletion of entire genes from plasmids
The Subcellular Distribution of Acyltransferases which Catalyze the Synthesis of Phosphoglycerides
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/65213/1/j.1432-1033.1969.tb00602.x.pd
Low Levels of DNA Polymerase Alpha Induce Mitotic and Meiotic Instability in the Ribosomal DNA Gene Cluster of Saccharomyces cerevisiae
The ribosomal DNA (rDNA) genes of Saccharomyces cerevisiae are located in a tandem array of about 150 repeats. Using a diploid with markers flanking and within the rDNA array, we showed that low levels of DNA polymerase alpha elevate recombination between both homologues and sister chromatids, about five-fold in mitotic cells and 30-fold in meiotic cells. This stimulation is independent of Fob1p, a protein required for the programmed replication fork block (RFB) in the rDNA. We observed that the fob1 mutation alone significantly increased meiotic, but not mitotic, rDNA recombination, suggesting a meiosis-specific role for this protein. We found that meiotic cells with low polymerase alpha had decreased Sir2p binding and increased Spo11p-catalyzed double-strand DNA breaks in the rDNA. Furthermore, meiotic crossover interference in the rDNA is absent. These results suggest that the hyper-Rec phenotypes resulting from low levels of DNA polymerase alpha in mitosis and meiosis reflect two fundamentally different mechanisms: the increased mitotic recombination is likely due to increased double-strand DNA breaks (DSBs) resulting from Fob1p-independent stalled replication forks, whereas the hyper-Rec meiotic phenotype results from increased levels of Spo11-catalyzed DSBs in the rDNA
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