We explore the masses, merger rates, eccentricities, and spins for field binary black holes (BHs) driven to merger by a third companion through the Lidov-Kozai mechanism. Using a population synthesis ...approach, we model the creation of stellar-mass BH triples across a range of different initial conditions and stellar metallicities. We find that the production of triple-mediated mergers is enhanced at low metallicities by a factor of ∼100 due to the lower BH natal kicks and reduced stellar mass loss. These triples naturally yield heavy binary BHs with near-zero effective spins, consistent with most of the mergers observed to date. This process produces a merger rate of between 2 and 25 Gpc−3 yr−1 in the local universe, suggesting that the Lidov-Kozai mechanism can potentially explain all of the low-spin, heavy BH mergers observed by Advanced LIGO/Virgo. Finally, we show that triples admit a unique eccentricity and spin distribution that will allow this model to be tested in the near future.
As the sensitivity of current and future gravitational-wave detectors improves, it will become possible to measure the evolution of the binary black hole merger rate with redshift. Here, we combine ...detailed fits to state-of-the-art dynamical models of binary black hole formation in dense star clusters with a cosmological model of cluster formation across cosmic time. We find a typical merger rate of 14 Gpc−3 yr−1 in the local universe, with a reasonable range of 4-18 Gpc−3 yr−1, depending on the rate of cluster disruption and the cluster initial mass function. This rate increases by a factor of 6 to redshift z = 2.7 before declining at higher redshifts. We compare the merger rate from binaries produced in clusters to similar estimates from isolated binaries and triples in galactic fields, and discuss various ways that these different formation channels could add up to the current merger rate observed by the Laser Interferometer Gravitational-Wave Observatory/Virgo.
Abstract
Globular clusters are among the oldest stellar populations in the Milky Way; consequently, they also host some of the oldest known stellar-mass black holes, providing insight into black hole ...formation and evolution in the early (
z
≳ 2) universe. Recent observations of supermassive black holes in elliptical galaxies have been invoked to suggest the possibility of a cosmological coupling between astrophysical black holes and the surrounding expanding universe, offering a mechanism for black holes to grow over cosmic time and potentially explaining the origin of dark energy. In this paper, I show that the mass functions of the two radial velocity black hole candidates in NGC 3201 place strong constraints on the cosmologically coupled growth of black holes. In particular, the amount of coupling required to explain the origin of dark energy would either require both NGC 3201 black holes to be nearly face on (a configuration with probability of at most 10
−4
) or one of the BHs would need to have formed with a mass below that of the most massive neutron stars (2.2
M
⊙
). This emphasizes that these and other detached black hole–star binaries can serve not only as laboratories for compact object and binary astrophysics but as constraints on the long-term evolution of astrophysical black holes.
Zygomycosis is an important emerging fungal infection, associated with high morbidity and mortality. The Working Group on Zygomycosis of the European Confederation of Medical Mycology (ECMM) ...prospectively collected cases of proven and probable zygomycosis in 13 European countries occurring between 2005 and 2007. Cases were recorded by a standardized case report form, entered into an electronic database and analysed descriptively and by logistic regression analysis. During the study period, 230 cases fulfilled pre-set criteria for eligibility. The median age of the patients was 50 years (range, 1 month to 87 years); 60% were men. Underlying conditions included haematological malignancies (44%), trauma (15%), haematopoietic stem cell transplantation (9%) and diabetes mellitus (9%). The most common manifestations of zygomycosis were pulmonary (30%), rhinocerebral (27%), soft tissue (26%) and disseminated disease (15%). Diagnosis was made by both histology and culture in 108 cases (44%). Among 172 cases with cultures, Rhizopus spp. (34%), Mucor spp. (19%) and Lichtheimia (formerly Absidia) spp. (19%) were most commonly identified. Thirty-nine per cent of patients received amphotericin B formulations, 7% posaconazole and 21% received both agents; 15% of patients received no antifungal therapy. Total mortality in the entire cohort was 47%. On multivariate analysis, factors associated with survival were trauma as an underlying condition (p 0.019), treatment with amphotericin B (p 0.006) and surgery (p <0.001); factors associated with death were higher age (p 0.005) and the administration of caspofungin prior to diagnosis (p 0.011). In conclusion, zygomycosis remains a highly lethal disease. Administration of amphotericin B and surgery, where feasible, significantly improve survival.
Conventional municipal wastewater treatment plants are not able to entirely degrade some organic pollutants that end up in the environment. Within this group of contaminants, Emerging Contaminants ...are mostly unregulated compounds that may be candidates for future regulation. In this work, different advanced technologies: solar heterogeneous photocatalysis with TiO2, solar photo-Fenton and ozonation, are studied as tertiary treatments for the remediation of micropollutants present in real municipal wastewater treatment plants effluents at pilot plant scale. Contaminants elimination was followed by Liquid Chromatography/Quadrupole ion trap Mass Spectrometry analysis after a pre-concentration 100:1 by automatic solid phase extraction. 66 target micropollutants were identified and quantified. 16 of those contaminants at initial concentrations over 1000 ng L−1, made up over 88% of the initial total effluent pollutant load. The order of micropollutants elimination efficiency under the experimental conditions evaluated was solar photo-Fenton > ozonation > solar heterogeneous photocatalysis with TiO2. Toxicity analyses by Vibrio fischeri and respirometric tests showed no significant changes in the effluent toxicity after the three tertiary treatments application. Solar photo-Fenton and ozonation treatments were also compared from an economical point of view.
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► Solar photo-Fenton as a promising tertiary treatment for MWTP effluents. ► A QTRAP was employed for monitoring micropollutants removal. ► Photocatalysis with TiO2 is very inefficient compared to solar photo-Fenton. ► Photo-Fenton is economically competitive with ozonation. ► Solar photo-Fenton investment cost is offset by the operating cost of ozonation.
Background:To estimate the incidence and prevalence of type 1 and type 2 diabetes in the UK general population from 1996 to 2005.Methods:Using The Health Improvement Network database, patients with ...type 1 or type 2 diabetes were identified who were 10–79 years old between 1996 and 2005. Prevalent cases (n = 49 999) were separated from incident cases (n = 42 642; type 1 = 1256, type 2 = 41 386). Data were collected on treatment patterns in incident cases, and on body mass index in prevalent and incident cases.Results:Diabetes prevalence increased from 2.8% in 1996 to 4.3% in 2005. The incidence of diabetes in the UK increased from 2.71 (2.58–2.85)/1000 person-years in 1996 to 4.42 (4.32–4.53)/1000 person-years in 2005. The incidence of type 1 diabetes remained relatively constant throughout the study period; however, the incidence of type 2 diabetes increased from 2.60 (2.47–2.74)/1000 person-years in 1996 to 4.31 (4.21–4.42)/1000 person-years in 2005. Between 1996 and 2005, the proportion of individuals newly diagnosed with type 2 diabetes who were obese increased from 46% to 56%. Treatment with metformin increased across the study period, while treatment with sulphonylureas decreased.Conclusions:The prevalence and incidence of type 2 diabetes have increased in the UK over the past decade. This might be primarily explained by the changes in obesity prevalence. Also, there was a change in drug treatment pattern from sulphonylureas to metformin.
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