12 research outputs found
Did the ancient egyptians record the period of the eclipsing binary Algol - the Raging one?
The eclipses in binary stars give precise information of orbital period
changes. Goodricke discovered the 2.867 days period in the eclipses of Algol in
the year 1783. The irregular orbital period changes of this longest known
eclipsing binary continue to puzzle astronomers. The mass transfer between the
two members of this binary should cause a long-term increase of the orbital
period, but observations over two centuries have not confirmed this effect.
Here, we present evidence indicating that the period of Algol was 2.850 days
three millenia ago. For religious reasons, the ancient Egyptians have recorded
this period into the Cairo Calendar, which describes the repetitive changes of
the Raging one. Cairo Calendar may be the oldest preserved historical document
of the discovery of a variable star.Comment: 26 pages, 5 figures, 11 table
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One‐Year Landmark Analysis of the Effect of Beta‐Blocker Dose on Survival After Acute Myocardial Infarction
Background Although beta‐blockers are recommended following myocardial infarction (MI), the benefits of long‐term treatment have not been established. The study's aim was to evaluate beta‐blocker efficacy by dose in 1‐year post‐MI survivors. Methods and Results The OBTAIN (Outcomes of Beta‐Blocker Therapy After Myocardial Infarction) registry included 7057 patients with acute MI, with 6077 one‐year survivors. For this landmark analysis, beta‐blocker dose status was available in 3004 patients and analyzed by use (binary) and dose at 1 year after MI. Doses were classified as no beta‐blocker and >0% to 12.5%, >12.5% to 25%, >25% to 50%, and >50% of target doses used in randomized clinical trials. Age was 63 to 64 years, and approximately two thirds were men. Median follow‐up duration was 1.05 years (interquartile range, 0.98–1.22). When analyzed dichotomously, beta‐blocker therapy was not associated with improved survival. When analyzed by dose, propensity score analysis showed significantly increased mortality in the no–beta‐blocker group (hazard ratio,1.997; 95% CI, 1.118–3.568; P 0% to 12.5% group (hazard ratio, 1.817; 95% CI, 1.094–3.016; P 25% to 50% group (hazard ratio, 1.764; 95% CI, 1.105–2.815; P 12.5% to 25% dose group. The mortality in the full‐dose group was not significantly higher (hazard ratio, 1.196; 95% CI, 0.687–2.083). In subgroup analyses, only history of congestive heart failure demonstrated significant interaction with beta‐blocker effects on survival. Conclusions This analysis suggests that patients treated with >12.5% to 25% of the target dose used in prior randomized clinical trials beyond 1 year after MI may have enhanced survival compared with no beta‐blocker and other beta‐blocker doses. A new paradigm for post‐MI beta‐blocker therapy is needed that addresses which patients should be treated, for how long, and at what dose
Effect of general anaesthesia on functional outcome in patients with anterior circulation ischaemic stroke having endovascular thrombectomy versus standard care: a meta-analysis of individual patient data
Background:
General anaesthesia (GA) during endovascular thrombectomy has been associated with worse patient outcomes in observational studies compared with patients treated without GA. We assessed functional outcome in ischaemic stroke patients with large vessel anterior circulation occlusion undergoing endovascular thrombectomy under GA, versus thrombectomy not under GA (with or without sedation) versus standard care (ie, no thrombectomy), stratified by the use of GA versus standard care.
Methods:
For this meta-analysis, patient-level data were pooled from all patients included in randomised trials in PuMed published between Jan 1, 2010, and May 31, 2017, that compared endovascular thrombectomy predominantly done with stent retrievers with standard care in anterior circulation ischaemic stroke patients (HERMES Collaboration). The primary outcome was functional outcome assessed by ordinal analysis of the modified Rankin scale (mRS) at 90 days in the GA and non-GA subgroups of patients treated with endovascular therapy versus those patients treated with standard care, adjusted for baseline prognostic variables. To account for between-trial variance we used mixed-effects modelling with a random effect for trials incorporated in all models. Bias was assessed using the Cochrane method. The meta-analysis was prospectively designed, but not registered.
Findings:
Seven trials were identified by our search; of 1764 patients included in these trials, 871 were allocated to endovascular thrombectomy and 893 were assigned standard care. After exclusion of 74 patients (72 did not undergo the procedure and two had missing data on anaesthetic strategy), 236 (30%) of 797 patients who had endovascular procedures were treated under GA. At baseline, patients receiving GA were younger and had a shorter delay between stroke onset and randomisation but they had similar pre-treatment clinical severity compared with patients who did not have GA. Endovascular thrombectomy improved functional outcome at 3 months both in patients who had GA (adjusted common odds ratio (cOR) 1·52, 95% CI 1·09–2·11, p=0·014) and in those who did not have GA (adjusted cOR 2·33, 95% CI 1·75–3·10, p<0·0001) versus standard care. However, outcomes were significantly better for patients who did not receive GA versus those who received GA (covariate-adjusted cOR 1·53, 95% CI 1·14–2·04, p=0·0044). The risk of bias and variability between studies was assessed to be low.
Interpretation:
Worse outcomes after endovascular thrombectomy were associated with GA, after adjustment for baseline prognostic variables. These data support avoidance of GA whenever possible. The procedure did, however, remain effective versus standard care in patients treated under GA, indicating that treatment should not be withheld in those who require anaesthesia for medical reasons