32 research outputs found
The vacuum bubbles in de Sitter background and black hole pair creation
We study the possible types of the nucleation of vacuum bubbles. We classify
vacuum bubbles in de Sitter background and present some numerical solutions.
The thin-wall approximation is employed to obtain the nucleation rate and the
radius of vacuum bubbles. With careful analysis we confirm that Parke's formula
is also applicable to the large true vacuum bubbles. The nucleation of the
false vacuum bubble in de Sitter background is also evaluated. The tunneling
process in the potential with degenerate vacua is analyzed as the limiting
cases of the large true vacuum bubble and false vacuum bubble. Next, we
consider the pair creation of black holes in the background of bubble
solutions. We obtain static bubble wall solutions of junction equation with
black hole pair. The masses of created black holes are uniquely determined by
the cosmological constant and surface tension on the wall. Finally, we obtain
the rate of pair creation of black holes.Comment: 3 figures, minor including errors and typos corrected, and refs.
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Expanding the stdpopsim species catalog, and lessons learned for realistic genome simulations
Simulation is a key tool in population genetics for both methods development and empirical research, but producing simulations that recapitulate the main features of genomic datasets remains a major obstacle. Today, more realistic simulations are possible thanks to large increases in the quantity and quality of available genetic data, and the sophistication of inference and simulation software. However, implementing these simulations still requires substantial time and specialized knowledge. These challenges are especially pronounced for simulating genomes for species that are not well-studied, since it is not always clear what information is required to produce simulations with a level of realism sufficient to confidently answer a given question. The community-developed framework stdpopsim seeks to lower this barrier by facilitating the simulation of complex population genetic models using up-to-date information. The initial version of stdpopsim focused on establishing this framework using six well-characterized model species (Adrion et al., 2020). Here, we report on major improvements made in the new release of stdpopsim (version 0.2), which includes a significant expansion of the species catalog and substantial additions to simulation capabilities. Features added to improve the realism of the simulated genomes include non-crossover recombination and provision of species-specific genomic annotations. Through community-driven efforts, we expanded the number of species in the catalog more than threefold and broadened coverage across the tree of life. During the process of expanding the catalog, we have identified common sticking points and developed the best practices for setting up genome-scale simulations. We describe the input data required for generating a realistic simulation, suggest good practices for obtaining the relevant information from the literature, and discuss common pitfalls and major considerations. These improvements to stdpopsim aim to further promote the use of realistic whole-genome population genetic simulations, especially in non-model organisms, making them available, transparent, and accessible to everyone
Radial PCI and the obesity paradox: Insights from Blue Cross Blue Shield of Michigan Cardiovascular Consortium (BMC2)
OBJECTIVE: To examine if transradial approach (TRA) negates the increased risk associated with femoral access in lean and morbidly obese patients undergoing percutaneous coronary intervention (PCI).
BACKGROUND: Patients at extremes of body mass are at increased risk of bleeding after PCI. TRA has been associated with lower overall rates of bleeding compared to femoral approach.
METHODS AND RESULTS: We studied patients undergoing emergent and elective PCI from 2010 to 2012 across 47 hospitals in Michigan who participate in the Blue Cross Blue Shield of Michigan Cardiovascular Consortium PCI registry. The primary outcomes were the incidences of bleeding and postprocedure transfusion. Propensity matching (PM) was used to adjust for nonrandomized use of TRA. TRA was used in 10,235 procedures. In PM analyses, use of TRA was associated with a reduction in bleeding (0.80 vs. 1.9%, odds ratio [OR] = 0.41, 95% confidence interval [CI] = 0.32-0.54, P \u3c 0.001) and need for transfusion (1.4 vs. 2.5%, OR = 0.56, 95% CI = 0.45-0.69, P \u3c 0.001) compared with femoral access. The absolute difference in bleeding and transfusion associated with TRA was largest in patients with lean body mass (BMI \u3c 25 kg/m(2)) and morbid obesity (BMI ≥ 40 kg/m(2)): Lean patients undergoing TRA had a rate of bleeding of 1.2 versus 2.8% for femoral access (OR = 0.43, 95% CI = 0.24-0.77, P = 0.002); and rate of transfusion of 2.4 versus 3.9% (OR = 0.61, 95% CI = 0.40-0.94, P = 0.019). The morbidly obese had a rate of bleeding of 0.8% for TRA versus 2.4% for femoral access (OR = 0.33, 95% CI = 0.44-0.72, P = 0.004); and rate of transfusion of 1.7 versus 3.0%, (OR = 0.55, 95% CI = 0.30-1.0, P = 0.051).
CONCLUSIONS: Compared with the femoral approach, TRA is associated with a reduction in bleeding across all patients undergoing PCI and the absolute benefit was greatest in those with extremely low or high BMI
Ninety-Day Readmission and Long-Term Mortality in Medicare Patients (≥65 Years) Treated With Ticagrelor Versus Prasugrel After Percutaneous Coronary Intervention (from the Blue Cross Blue Shield of Michigan Cardiovascular Consortium)
Ticagrelor and prasugrel were found to be superior to clopidogrel for the treatment of acute coronary syndrome (ACS) after percutaneous coronary intervention (PCI); however, the comparative effectiveness of these 2 drugs remains unknown. We compared postdischarge outcomes among older patients treated with ticagrelor versus prasugrel after PCI for ACS. We linked clinical data from PCIs performed in older patients (age ≥65) for ACS at 47 Michigan hospitals to Medicare fee-for-service claims from January 1, 2013, to December 31, 2014, to ascertain rates of 90-day readmission and long-term mortality. We used propensity score matching to adjust for the nonrandom use of ticagrelor and prasugrel at discharge. Logistic regression and Cox proportional hazards models were used to compare rates of 90-day readmission and long-term mortality, respectively. Patients discharged on ticagrelor (n = 1,243) were more frequently older, female, had a history of cerebrovascular disease, and presented with ST- or non-ST-elevation myocardial infarction compared with prasugrel (n = 1,014). After matching (n = 756 per group), there were no significant differences in the rates of 90-day readmission (16.7% ticagrelor vs 14.6% prasugrel; adjusted odds ratio 1.15, 95% confidence interval 0.86 to 1.55, p = 0.35) or 1-year mortality (5.4% ticagrelor vs 3.7% prasugrel; hazard ratio 1.3, 95% confidence interval 0.8 to 2.2, p = 0.31). In conclusion, we found no significant differences in the rates of 90-day readmission or long-term mortality between older patients treated with ticagrelor and patients treated with prasugrel after PCI for ACS. In the absence of randomized data to the contrary, these 2 treatments appear similarly effective
Treatment of Acute Myocardial Infarction and Cardiogenic Shock: Outcomes of the RECOVER III Postapproval Study by Society of Cardiovascular Angiography and Interventions Shock Stage
Background The Society for Cardiovascular Angiography and Interventions proposed a staging system (A–E) to predict prognosis in cardiogenic shock. Herein, we report clinical outcomes of the RECOVER III study for the first time, according to Society for Cardiovascular Angiography and Interventions shock classification. Methods and Results The RECOVER III study is an observational, prospective, multicenter, single‐arm, postapproval study of patients with acute myocardial infarction with cardiogenic shock undergoing percutaneous coronary intervention with Impella support. Patients enrolled in the RECOVER III study were assigned a baseline Society for Cardiovascular Angiography and Interventions shock stage. Staging was then repeated within 24 hours after initiation of Impella. Kaplan‐Meier survival curve analyses were conducted to assess survival across Society for Cardiovascular Angiography and Interventions shock stages at both time points. At baseline assessment, 16.5%, 11.4%, and 72.2% were classified as stage C, D, and E, respectively. At ≤24‐hour assessment, 26.4%, 33.2%, and 40.0% were classified as stage C, D, and E, respectively. Thirty‐day survival among patients with stage C, D, and E shock at baseline was 59.7%, 56.5%, and 42.9%, respectively (P=0.003). Survival among patients with stage C, D, and E shock at ≤24 hours was 65.7%, 52.1%, and 29.5%, respectively (P<0.001). After multivariable analysis of impact of shock stage classifications at baseline and ≤24 hours, only stage E classification at ≤24 hours was a significant predictor of mortality (odds ratio, 4.8; P<0.001). Conclusions In a real‐world cohort of patients with acute myocardial infarction with cardiogenic shock undergoing percutaneous coronary intervention with Impella support, only stage E classification at ≤24 hours was significantly predictive of mortality, suggesting that response to therapy may be more important than clinical severity of shock at presentation
Treatment of Acute Myocardial Infarction and Cardiogenic Shock: Outcomes of the RECOVER III Postapproval Study by Society of Cardiovascular Angiography and Interventions Shock Stage
BACKGROUND: The Society for Cardiovascular Angiography and Interventions proposed a staging system (A-E) to predict prognosis in cardiogenic shock. Herein, we report clinical outcomes of the RECOVER III study for the first time, according to Society for Cardiovascular Angiography and Interventions shock classification. METHODS AND RESULTS: The RECOVER III study is an observational, prospective, multicenter, single-arm, postapproval study of patients with acute myocardial infarction with cardiogenic shock undergoing percutaneous coronary intervention with Impella support. Patients enrolled in the RECOVER III study were assigned a baseline Society for Cardiovascular Angiography and Interventions shock stage. Staging was then repeated within 24 hours after initiation of Impella. Kaplan-Meier survival curve analyses were conducted to assess survival across Society for Cardiovascular Angiography and Interventions shock stages at both time points. At baseline assessment, 16.5%, 11.4%, and 72.2% were classified as stage C, D, and E, respectively. At ≤24-hour assessment, 26.4%, 33.2%, and 40.0% were classified as stage C, D, and E, respectively. Thirty-day survival among patients with stage C, D, and E shock at baseline was 59.7%, 56.5%, and 42.9%, respectively (=0.003). Survival among patients with stage C, D, and E shock at ≤24 hours was 65.7%, 52.1%, and 29.5%, respectively (\u3c0.001). After multivariable analysis of impact of shock stage classifications at baseline and ≤24 hours, only stage E classification at ≤24 hours was a significant predictor of mortality (odds ratio, 4.8; \u3c0.001). CONCLUSIONS: In a real-world cohort of patients with acute myocardial infarction with cardiogenic shock undergoing percutaneous coronary intervention with Impella support, only stage E classification at ≤24 hours was significantly predictive of mortality, suggesting that response to therapy may be more important than clinical severity of shock at presentation