137 research outputs found

    Degeneracy between mass and spin in black-hole-binary waveforms

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    We explore the degeneracy between mass and spin in gravitational waveforms emitted by black-hole binary coalescences. We focus on spin-aligned waveforms and obtain our results using phenomenological models that were tuned to numerical-relativity simulations. A degeneracy is known for low-mass binaries (particularly neutron-star binaries), where gravitational-wave detectors are sensitive to only the inspiral phase, and the waveform can be modelled by post-Newtonian theory. Here, we consider black-hole binaries, where detectors will also be sensitive to the merger and ringdown, and demonstrate that the degeneracy persists across a broad mass range. At low masses, the degeneracy is between mass ratio and total spin, with chirp mass accurately determined. At higher masses, the degeneracy persists but is not so clearly characterised by constant chirp mass as the merger and ringdown become more significant. We consider the importance of this degeneracy both for performing searches (including searches where only non-spinning templates are used) and in parameter extraction from observed systems. We compare observational capabilities between the early (~2015) and final (2018 onwards) versions of the Advanced LIGO detector.Comment: 11 pages, 9 figure

    eReefs modelling suggests Trichodesmium may be a major nitrogen source in the Great Barrier Reef

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    Trichodesmium can fix nitrogen that is later released into the water column. This process may be a major source of ‘new’ nitrogen in the Great Barrier Reef (GBR), but to date this contribution is poorly resolved. We have estimated the seasonal, spatial and annual contributions of Trichodesmium to the annual nitrogen budget of the GBR using the eReefs marine models. Models were run for the interval December 2010 to November 2012. During this period La Niña conditions produced record rainfalls and widespread flooding of GBR catchments. Model outputs suggest nitrogen fixation by Trichodesmium in the GBR (which covers about 348,000 km2) contributes approximately 0.5 MT/yr, exceeding the total average annual riverine nitrogen loads (0.05–0.08 MT/yr). Nitrogen fixation loads are exceeded by riverine loads only if the comparison is restricted to inshore waters and during the wet season. The river pollution is likely to have impacts in freshwater wetlands, mangroves, seagrasses and in-shore coral reefs; while Trichodesmium blooms are likely to be less intense but more widespread and affect offshore coral reefs and other oceanic ecosystems. Phosphorus and iron are suggested to be potential drivers of Trichodesmium growth and nitrogen fixation. This result is provisional but reinforces the need for more detailed assessment and reliable quantification of the annual nitrogen contribution from nitrogen fixation in the GBR and other coastal waters. Such advances will improve understandings of the role of terrestrial nitrogen loads in the GBR and of terrestrial phosphorus and iron loads which can modulate Trichodesmium abundance. These findings will help to broaden the focus of water quality management programmes and support management to improve GBR water quality

    Research priorities for the management of broken bones of the upper limb in people over 50: A UK priority setting partnership with the James Lind Alliance

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    Objective. To determine research priorities for the management of broken bones of the upper limb in people over 50 which represent the shared priorities of patients, their families, carers and healthcare professionals. Design/setting. A national (UK) research priority-setting partnership. Participants. People aged 50 and over who have experienced a fracture of the upper limb; carers involved in their care; family and friends of patients; healthcare professionals involved in the treatment of these patients. Methods. Using a multiphase methodology in partnership with the James Lind Alliance over 15 months (September 2017 – December 2018), a national scoping survey asked respondents to submit their research uncertainties. These were amalgamated into a smaller number of research questions. The existing evidence was searched to ensure that the questions had not already been answered. A second national survey asked respondents to prioritise the research questions. A final shortlist of 25 questions was taken to a multistakeholder workshop where a consensus was reached on the top 10 priorities. Results. There were 1898 original uncertainties submitted by 328 respondents to the first survey. These original uncertainties were refined into 51 research questions of which 50 were judged to be true uncertainties following a review of the research evidence. There were 209 respondents to the second (interim prioritisation) survey. The top 10 priorities encompass a broad range of uncertainties in management and rehabilitation of upper limb fractures. Conclusions. The top 10 UK research priorities highlight uncertainties in how we assess outcomes, provide information, achieve pain control, rationalise surgical intervention, optimise rehabilitation and provide psychological support. The breadth of these research areas highlights the value of this methodology. This work should help to steer research in this area for the next 5-10 years and the challenge for researchers now is to refine and deliver answers to these research priorities

    Inflammatory Properties and Adjuvant Potential of Synthetic Glycolipids Homologous to Mycolate Esters of the Cell Wall of Mycobacterium tuberculosis

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    &lt;p&gt;The cell wall of mycobacteria is characterised by glycolipids composed of different classes of mycolic acids (MAs; alpha-, keto-, and methoxy-) and sugars (trehalose, glucose, and arabinose). Studies using mutant Mtb strains have shown that the structure of MAs influences the inflammatory potential of these glycolipids. As mutant Mtb strains possess a complex mixture of glycolipids, we analysed the inflammatory potential of single classes of mycolate esters of the Mtb cell wall using 38 different synthetic analogues. Our results show that synthetic trehalose dimycolate (TDM) and trehalose, glucose, and arabinose monomycolates (TMM, GMM, and AraMM) activate bone marrow-derived dendritic cells in terms of the production of pro-inflammatory cytokines (IL-6 and TNF-&amp;alpha;) and reactive oxygen species, upregulation of costimulatory molecules, and activation of NLRP3 inflammasome by a mechanism dependent on Mincle. These findings demonstrate that Mincle receptor can also recognise pentose esters and seem to contradict the hypothesis that production of GMM is an escape mechanism used by pathogenic mycobacteria to avoid recognition by the innate immune system. Finally, our experiments indicate that TMM and GMM, as well as TDM, can promote Th1 and Th17 responses in mice in an OVA immunisation model, and that further analysis of their potential as novel adjuvants for subunit vaccines is warranted.&lt;/p&gt;</p

    Integration of HIV/AIDS services into African primary health care: lessons learned for health system strengthening in Mozambique - a case study

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    <p>Abstract</p> <p>Introduction</p> <p>In 2004, Mozambique, supported by large increases in international disease-specific funding, initiated a national rapid scale-up of antiretroviral treatment (ART) and HIV care through a vertical "Day Hospital" approach. Though this model showed substantial increases in people receiving treatment, it diverted scarce resources away from the primary health care (PHC) system. In 2005, the Ministry of Health (MOH) began an effort to use HIV/AIDS treatment and care resources as a means to strengthen their PHC system. The MOH worked closely with a number of NGOs to integrate HIV programs more effectively into existing public-sector PHC services.</p> <p>Case Description</p> <p>In 2005, the Ministry of Health and Health Alliance International initiated an effort in two provinces to integrate ART into the existing primary health care system through health units distributed across 23 districts. Integration included: a) placing ART services in existing units; b) retraining existing workers; c) strengthening laboratories, testing, and referral linkages; e) expanding testing in TB wards; f) integrating HIV and antenatal services; and g) improving district-level management. Discussion: By 2008, treatment was available in nearly 67 health facilities in 23 districts. Nearly 30,000 adults were on ART. Over 80,000 enrolled in the HIV/AIDS program. Loss to follow-up from antenatal and TB testing to ART services has declined from 70% to less than 10% in many integrated sites. Average time from HIV testing to ART initiation is significantly faster and adherence to ART is better in smaller peripheral clinics than in vertical day hospitals. Integration has also improved other non-HIV aspects of primary health care.</p> <p>Conclusion</p> <p>The integration approach enables the public sector PHC system to test more patients for HIV, place more patients on ART more quickly and efficiently, reduce loss-to-follow-up, and achieve greater geographic HIV care coverage compared to the vertical model. Through the integration process, HIV resources have been used to rehabilitate PHC infrastructure (including laboratories and pharmacies), strengthen supervision, fill workforce gaps, and improve patient flow between services and facilities in ways that can benefit all programs. Using aid resources to integrate and better link HIV care with existing services can strengthen wider PHC systems.</p

    Best practice guidelines for cetacean tagging

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    Animal-borne electronic instruments (tags) are valuable tools for collecting information on cetacean physiology, behaviour and ecology, and for enhancing conservation and management policies for cetacean populations. Tags allow researchers to track the movement patterns, habitat use andother aspects of the behaviour of animals that are otherwise difficult to observe. They can even be used to monitor the physiology of a tagged animal within its changing environment. Such tags are ideal for identifying and predicting responses to anthropogenic threats, thus facilitating the development of robust mitigation measures. With the increasing need for data best provided by tagging and the increasing availability of tags, such research is becoming more common. Tagging can, however, pose risks to the health and welfare of cetaceans and to personnel involved in tagging operations. Here we provide ‘best practice’ recommendations for cetacean tag design, deployment and follow-up assessment of tagged individuals, compiled by biologists and veterinarians with significant experience in cetacean tagging. This paper is intended to serve as a resource to assist tag users, veterinarians, ethics committees and regulatory agency staff in the implementation of high standards of practice, and to promote the training of specialists in this area. Standardised terminology for describing tag design and illustrations of tag types and attachment sites are provided, along with protocols for tag testing and deployment (both remote and through capture-release), including training of operators. The recommendations emphasise the importance of ensuring that tagging is ethically and scientifically justified for a particular project and that tagging only be used to address bona fide research or conservation questions that are best addressed with tagging, as supported by an exploration of alternative methods. Recommendations are provided for minimising effects on individual animals (e.g. through careful selection of the individual, tag design and implant sterilisation) and for improving knowledge of tagging effects on cetaceans through increased post-tagging monitoring.Publisher PDFPeer reviewe

    Introductory programming: a systematic literature review

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    As computing becomes a mainstream discipline embedded in the school curriculum and acts as an enabler for an increasing range of academic disciplines in higher education, the literature on introductory programming is growing. Although there have been several reviews that focus on specific aspects of introductory programming, there has been no broad overview of the literature exploring recent trends across the breadth of introductory programming. This paper is the report of an ITiCSE working group that conducted a systematic review in order to gain an overview of the introductory programming literature. Partitioning the literature into papers addressing the student, teaching, the curriculum, and assessment, we explore trends, highlight advances in knowledge over the past 15 years, and indicate possible directions for future research

    A Biobank of Breast Cancer Explants with Preserved Intra-tumor Heterogeneity to Screen Anticancer Compounds.

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    The inter- and intra-tumor heterogeneity of breast cancer needs to be adequately captured in pre-clinical models. We have created a large collection of breast cancer patient-derived tumor xenografts (PDTXs), in which the morphological and molecular characteristics of the originating tumor are preserved through passaging in the mouse. An integrated platform combining in vivo maintenance of these PDTXs along with short-term cultures of PDTX-derived tumor cells (PDTCs) was optimized. Remarkably, the intra-tumor genomic clonal architecture present in the originating breast cancers was mostly preserved upon serial passaging in xenografts and in short-term cultured PDTCs. We assessed drug responses in PDTCs on a high-throughput platform and validated several ex vivo responses in vivo. The biobank represents a powerful resource for pre-clinical breast cancer pharmacogenomic studies (http://caldaslab.cruk.cam.ac.uk/bcape), including identification of biomarkers of response or resistance.This research was supported with funding from Cancer Research UK and from the European Union to the EUROCAN Network of Excellence (FP7; grant numnumber 260791). M.C. has received funding from the European Union’s Horizon 2020 research and innovation program under the Marie Sk1odowska-Curie grant agreement no. 660060 and was supported by the Department of Experimental Oncology and Molecular Medicine, Fondazione IRCCS Istituto Nazionale dei Tumori, Milan, Italy. R.N.B. is supported by the Wellcome Trust PhD Programme in Mathematical Genomics and Medicine. S-J.S. is supported by the Wellcome Trust PhD Programme for Clinicians in Cambridge. A.Bruna, O.M.R., E.M., V.S., and C.C. are members of the EurOPDX Consortium. Weare very grateful for the generosity of all the patients that donated samples for implantation. We are also deeply indebted to all the staff (surgeons, pathologists, oncologists, theatre staff, and other ancillary personnel) at the Cambridge Breast Unit, Cambridge University Hospital NHS Foundation Trust, for facilitating the timely collection of samples. We thank the Cancer Research UK Cambridge Institute Genomics, Bioinformatics, Histopathology, Flow Cytometry, Biological Resource, and Bio-repository Core Facilities for support during the execution of this project.This is the final version of the article. It first appeared from Elsevier at http://dx.doi.org/10.1016/j.cell.2016.08.041
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