103 research outputs found
Star clusters near and far; tracing star formation across cosmic time
© 2020 Springer-Verlag. The final publication is available at Springer via https://doi.org/10.1007/s11214-020-00690-x.Star clusters are fundamental units of stellar feedback and unique tracers of their host galactic properties. In this review, we will first focus on their constituents, i.e.\ detailed insight into their stellar populations and their surrounding ionised, warm, neutral, and molecular gas. We, then, move beyond the Local Group to review star cluster populations at various evolutionary stages, and in diverse galactic environmental conditions accessible in the local Universe. At high redshift, where conditions for cluster formation and evolution are more extreme, we are only able to observe the integrated light of a handful of objects that we believe will become globular clusters. We therefore discuss how numerical and analytical methods, informed by the observed properties of cluster populations in the local Universe, are used to develop sophisticated simulations potentially capable of disentangling the genetic map of galaxy formation and assembly that is carried by globular cluster populations.Peer reviewedFinal Accepted Versio
Genome-Wide Association Study in BRCA1 Mutation Carriers Identifies Novel Loci Associated with Breast and Ovarian Cancer Risk
BRCA1-associated breast and ovarian cancer risks can be modified by common genetic variants. To identify further cancer risk-modifying loci, we performed a multi-stage GWAS of 11,705 BRCA1 carriers (of whom 5,920 were diagnosed with breast and 1,839 were diagnosed with ovarian cancer), with a further replication in an additional sample of 2,646 BRCA1 carriers. We identified a novel breast cancer risk modifier locus at 1q32 for BRCA1 carriers (rs2290854, P = 2.7×10-8, HR = 1.14, 95% CI: 1.09-1.20). In addition, we identified two novel ovarian cancer risk modifier loci: 17q21.31 (rs17631303, P = 1.4×10-8, HR = 1.27, 95% CI: 1.17-1.38) and 4q32.3 (rs4691139, P = 3.4×10-8, HR = 1.20, 95% CI: 1.17-1.38). The 4q32.3 locus was not associated with ovarian cancer risk in the general population or BRCA2 carriers, suggesting a BRCA1-specific associat
Open data from the third observing run of LIGO, Virgo, KAGRA, and GEO
The global network of gravitational-wave observatories now includes five detectors, namely LIGO Hanford, LIGO Livingston, Virgo, KAGRA, and GEO 600. These detectors collected data during their third observing run, O3, composed of three phases: O3a starting in 2019 April and lasting six months, O3b starting in 2019 November and lasting five months, and O3GK starting in 2020 April and lasting two weeks. In this paper we describe these data and various other science products that can be freely accessed through the Gravitational Wave Open Science Center at https://gwosc.org. The main data set, consisting of the gravitational-wave strain time series that contains the astrophysical signals, is released together with supporting data useful for their analysis and documentation, tutorials, as well as analysis software packages
Characterizing the continental basement of the Central Andes: Constraints from Bolivian crustal xenoliths
A critical factor in understanding the development of active continental margins is knowledge of the crustal basement on which magmatic arcs are built. This study reports results from a whole-rock geochemical and zircon U-Pb geochronological study of a suite of crustal xenoliths from the Bolivian Altiplano, Central Andes, that provide new insight into the evolution and composition of the continental basement beneath the region. The xenoliths are hosted in Pliocene–Pleistocene trachyandesitic to dacitic lavas that erupted from monogenetic volcanic centers in the Andean backarc region and comprise both igneous and metamorphic lithologies, including diorites, microgranites, gneisses, garnet–mica schists, granulites, quartzites, and dacites. The xenolith suite exhibits significant Sr-isotopic heterogeneity, with values extending from 0.7105 to 0.7368. Pb isotopic signatures reflect the crustal domains previously constrained from scattered exposures of basement rocks throughout the region. Ion microprobe U-Pb dating of cores and rims from zircon separates from two of the sampled xenoliths reveals predominant early Phanerozoic age peaks (ca. 500 Ma; population 1), late Mesoproterozoic age peaks (1.0–1.2 Ga; population 2), and Paleoproterozoic age peaks (1.7–1.9 Ga; population 3). Populations 1 and 2 are well documented throughout the Andes and correspond to periods of supercontinent formation (e.g., Rodinia at ca. 1.0 Ga) and breakup. Population 3, which is poorly represented in the zircon record of the Andes as a whole, may record geological events during the construction of the Paleoproterozoic Amazonian Craton. The presence of the three age peaks in the detrital zircon population record of a single crustal xenolith demonstrates the important role of crustal recycling in the construction of the modern-day Andean margin. The lithological character of the xenoliths and their detrital zircon ages are inconsistent with current understanding of the eastern extent of the Arequipa-Antofalla basement block beneath the Bolivian Altiplano and instead indicate that it terminates further to the west than previously assumed
Effect of inositol hexaphosphate (IP6) on UVB-induced skin tumor development in SKH 1 hairless mice.
Inositol hexaphosphate (IP6) is a naturally occurring polyphosphorylated carbohydrate that is abundant in many plants and in various high-fiber foods, such as cereals and legumes. IP6 has a striking, broad-spectrum anticancer activity in various in vitro and animal models, in which it interferes with key pathways in malignancy to inhibit cell proliferation, cell-cycle progression, metastasis, invasion, and angiogenesis and to induce apoptosis. In this study, we investigated the protective effects of IP6 in drinking water on the incidence of UVB-induced skin cancer in the SKH1 (Crl: SKH1-hr) mouse model. One group of 15 mice received 2% IP6 in drinking water and UVB exposure, and the other group (n = 15) received UVB exposure only. All mice in both groups were fed an IP6-deficient diet (AIN 76A). The treatment group started receiving 2% IP6 in the drinking water 3 d before irradiation. Mice were irradiated 3 times each week, starting at a dose of 1.5 kJ/m2, with weekly increases in increments of 1.5 kJ/m2 to a final dose of 7.5 kJ/m2. Tumor formation was monitored until the week 31. IP6 in drinking water significantly decreased tumor incidence by 5-fold and tumor multiplicity by 4-fold. These results show that IP6 has an antiphotocarcinogenic effect and can protect against UVB-induced tumor formation
The use of multivariate analysis of karyotypesto determine relationships between species of Opuntia
A Global Perspective on the Population Structure and Reproductive System of Phyllosticta citricarpa
The citrus pathogen Phyllosticta citricarpa was first described 117 years ago in Australia, and subsequently from the summer rainfall citrus-growing regions in China, Africa, South America and recently the United States of America (USA). Limited information is available on the pathogen's population structure, mode of reproduction and introduction pathways, which were investigated by genotyping 383 isolates representing 12 populations from South Africa, USA, Australia, China and Brazil. Populations were genotyped using seven published and eight newly developed polymorphic simple sequence repeat (SSR) markers. The Chinese and Australian populations had the highest genetic diversities, whereas populations from Brazil, USA and South Africa exhibited characteristics of founder populations. The USA population was clonal. Based on principal coordinate and minimum spanning network analyses the Chinese populations were distinct from the other populations. Population differentiation and clustering analyses revealed high connectivity and possibly linked introduction pathways between South Africa, Australia and Brazil. With the exception of the clonal USA populations that only contained one mating type, all the other populations contained both mating types in a ratio that did not deviate significantly from 1:1. Whilst most populations exhibited sexual reproduction, linkage disequilibrium analyses indicated that asexual reproduction is important in the pathogen's life cycle.This work was financially supported by Citrus Research International
and The Technology and Human Resources for Industry Programme.
We thank CenGen (Pty.) Ltd., and S. Langenhoven and A. Pretorius
(Department of Plant Pathology, Stellenbosch University), for assistance in
the laboratory and technical support; and S. Maduna and A. van der Merwe
(Department of Genetics, Stellenbosch University) for assistance with
analyses in R
Benchmarking key service quality indicators in UK Employee Assistance Programme Counselling: A CORE System data profile
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