86 research outputs found

    The Large-Scale Distribution and Motions of Older Stars in Orion

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    We review the current knowledge of the population of `older' stars in the Orion OB1 association, specifically those in subgroups 1a and 1b. We briefly outline the history of the subject and then continue with a summary of the present state of knowledge of the early-type stars in Orion OB1. New results from the Hipparcos parallaxes and proper motions will be presented. The main result is that subgroup 1a is located at about 330 pc from the Sun, much closer than the previously determined distance, and about 100 pc distant from the other subgroups of the association and the Orion molecular clouds. Unfortunately, due to the unfavorable kinematics of the association with respect to the Galactic background, Hipparcos proper motions do not allow a clear kinematic separation of the association from the field. For this purpose accurate and homogeneous radial velocities are needed. Traditionally, the massive O and B stars have received most of the attention in the studies of OB associations. However, we will present results showing that significant numbers of low-mass stars are associated with Orion OB1. Unbiased, optically complete, spectroscopic and photometric surveys of areas within subgroups 1a and 1b have the potential to determine the complete low-mass stellar population, down to the brown dwarf limit. This will provide much insight into the overall initial mass function and studies of the kinematics of the low-mass stars will yield insights into the dispersal of the association.Comment: To appear in The Orion Complex Revisited, eds. M. J. McCaughrean & A. Burkert (San Francisco, ASP), gzipped tar-file, 22 pages 7 EPS-figures, LaTeX using paspconf.sty and psfig.tex. Wrongly quoted errors on the average parallaxes of the Orion OB1 subgroups were corrected (Section 4

    Spent pleurotus ostreatus substrate has potential for managing Fusarium Wilt of Banana

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    A range of basidiomycetes including the edible mushroom Pleurotus ostreatus (Po) can suppress plant pathogens such as Fusarium spp. With the current increase in production and consumption of Po in Uganda, the spent Po substrate (SPoS) could be an alternative to manage Fusarium wilt of banana (FWB), caused by the soil borne pathogen Fusarium oxysporum f. sp. cubense, race 1 (Foc). This study determined the potential of SPoS to inhibit Foc in vitro and in potted plants. In vitro studies confirmed suppression of Foc in pure co-culture (Po vs. Foc) assays and media amended with different concentrations (0% to 50% w/v) of un-sterilized SPoS filtrates. Foc growth in the sterile SPoS filtrate was comparable to the water control, suggesting possible roles of biotic or thermolabile components of the SPoS. To further verify the suppressive effects of SPoS, pot experiments were carried out with a resistant (‘Mbwazirume’, AAA) and susceptible (‘Sukali Ndizi’, AAB) banana cultivar using both artificially and naturally infested soils. Independent of the inoculation method, SPoS significantly reduced the severity of FWB in pot experiments. Susceptible cultivar ‘Sukali Ndizi’ growing in substrates amended with SPoS showed lower (1.25) corm damage (Scale 0–5) than the un-amended control (3.75). No corm damage was observed in uninoculated controls. The resistant cultivar ‘Mbwazirume’, showed slight (0.25) corm damage only in the Foc-inoculated plants without SPoS. These findings suggest that SPoS could be used as part of the management practices to reduce the impact of FWB

    Can edible mushrooms boost soil health in banana organic systems?

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    Manipulation of the rhizosphere can improve soil health; and foster sustainable management of pests and diseases. Biological inputs such as spent substrates from edible mushrooms (e.g., Pleurotus ostreatus) gardens offer sustainable alternatives on that direction. This work presents a meta-analysis of major trends in knowledge generation on edible mushroom use in agriculture, especially to benefit the crop rhizosphere. It further delves into a detailed synthesis of the effects of spent mushroom wastes (SMW) on the physical, chemical, and biological properties of the soil rhizosphere and agroecosystems. The review concludes by providing an outlook on how SMW can potentially support the management of key soil health challenges in organic banana production systems

    First report of banana bunchy top disease caused by Banana bunchy top virus in Uganda

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    Banana bunchy top virus (BBTV) that causes banana bunchy top disease (BBTD) is ranked among the top 100 invasive species in the world. Despite being omnipresent in the Democratic Republic of Congo (DR Congo) and South-Western Rwanda for over 2 decades, BBTV had not been reported in neighbouring Uganda. However, in 2020, banana plants with BBTD characteristic symptoms were observed in Arua City located in the North Western part of Uganda, bordering DR Congo. BBTV in these plants was confirmed using PCR and the comparison of the genomic DNA nucleotide sequence with nucleotide sequences in NCBI data base (https://www.ncbi.nlm.nih.gov/). The gDNA nucleotide sequence had 98-99% similarity with BBTV isolates form different countries in Africa, Asia, South Pacific and the USA. These results constitute the first confirmation of BBTD in Uganda. This infection is anticipated to have been introduced from DR Congo, mainly through infected planting materials. Once established, BBTD is very difficult to control on small-scale farms. It is therefore crucial to urgently understand the current spread of the virus, determine its risk to banana production in Uganda and devise proactive measures for its management

    Toward a General Theory of Standards of Proof

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    Which standard of proof is best for a particular type of case This deceptively simple question has been much discussed but the current state of understanding is unsatisfactory Statisticians posed a general answer philosophers and others launched an assault on that answer practically oriented scholars draw on both strains unsystematically and courts generally offer little or no reasoning for their decisions The goal of this article is to outline a systematic and complete justification for selecting one probabilistic standard of proof over another By training a microscope on one small corner of the law incapacity will contests this article demonstrates the relevance of old factors identifies several new factors and integrates the factors into an approach that will hopefully guide future inquiry One important implication is that the choice of proof standard will almost necessarily be tentative too much is unknown or unknowabl

    Combined Associations of a Polygenic Risk Score and Classical Risk Factors With Breast Cancer Risk.

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    We evaluated the joint associations between a new 313-variant PRS (PRS313) and questionnaire-based breast cancer risk factors for women of European ancestry, using 72 284 cases and 80 354 controls from the Breast Cancer Association Consortium. Interactions were evaluated using standard logistic regression and a newly developed case-only method for breast cancer risk overall and by estrogen receptor status. After accounting for multiple testing, we did not find evidence that per-standard deviation PRS313 odds ratio differed across strata defined by individual risk factors. Goodness-of-fit tests did not reject the assumption of a multiplicative model between PRS313 and each risk factor. Variation in projected absolute lifetime risk of breast cancer associated with classical risk factors was greater for women with higher genetic risk (PRS313 and family history) and, on average, 17.5% higher in the highest vs lowest deciles of genetic risk. These findings have implications for risk prevention for women at increased risk of breast cancer

    Polygenic Risk Scores for Prediction of Breast Cancer and Breast Cancer Subtypes

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    Stratification of women according to their risk of breast cancer based on polygenic risk scores (PRSs) could improve screening and prevention strategies. Our aim was to develop PRSs, optimized for prediction of estrogen receptor (ER)-specific disease, from the largest available genome-wide association dataset and to empirically validate the PRSs in prospective studies. The development dataset comprised 94,075 case subjects and 75,017 control subjects of European ancestry from 69 studies, divided into training and validation sets. Samples were genotyped using genome-wide arrays, and single-nucleotide polymorphisms (SNPs) were selected by stepwise regression or lasso penalized regression. The best performing PRSs were validated in an independent test set comprising 11,428 case subjects and 18,323 control subjects from 10 prospective studies and 190,040 women from UK Biobank (3,215 incident breast cancers). For the best PRSs (313 SNPs), the odds ratio for overall disease per 1 standard deviation in ten prospective studies was 1.61 (95%CI: 1.57-1.65) with area under receiver-operator curve (AUC) = 0.630 (95%CI: 0.628-0.651). The lifetime risk of overall breast cancer in the top centile of the PRSs was 32.6%. Compared with women in the middle quintile, those in the highest 1% of risk had 4.37- and 2.78-fold risks, and those in the lowest 1% of risk had 0.16- and 0.27-fold risks, of developing ER-positive and ER-negative disease, respectively. Goodness-of-fit tests indicated that this PRS was well calibrated and predicts disease risk accurately in the tails of the distribution. This PRS is a powerful and reliable predictor of breast cancer risk that may improve breast cancer prevention programs.NovartisEli Lilly and CompanyAstraZenecaAbbViePfizer UKCelgeneEisaiGenentechMerck Sharp and DohmeRocheCancer Research UKGovernment of CanadaArray BioPharmaGenome CanadaNational Institutes of HealthEuropean CommissionMinistère de l'Économie, de l’Innovation et des Exportations du QuébecSeventh Framework ProgrammeCanadian Institutes of Health Researc

    New genetic loci link adipose and insulin biology to body fat distribution.

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    Body fat distribution is a heritable trait and a well-established predictor of adverse metabolic outcomes, independent of overall adiposity. To increase our understanding of the genetic basis of body fat distribution and its molecular links to cardiometabolic traits, here we conduct genome-wide association meta-analyses of traits related to waist and hip circumferences in up to 224,459 individuals. We identify 49 loci (33 new) associated with waist-to-hip ratio adjusted for body mass index (BMI), and an additional 19 loci newly associated with related waist and hip circumference measures (P < 5 × 10(-8)). In total, 20 of the 49 waist-to-hip ratio adjusted for BMI loci show significant sexual dimorphism, 19 of which display a stronger effect in women. The identified loci were enriched for genes expressed in adipose tissue and for putative regulatory elements in adipocytes. Pathway analyses implicated adipogenesis, angiogenesis, transcriptional regulation and insulin resistance as processes affecting fat distribution, providing insight into potential pathophysiological mechanisms
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