426 research outputs found

    Modelling phosphorus fluxes in Loweswater

    Get PDF
    1. This is the final report to the Loweswater Care Project (in support of the Catchment Restoration Fund for England) ECRC-ENSIS Project 298, 'Loweswater 12-13'. The study was concerned with the spatial and temporal concentrations of sediment phosphorus (P) in the lake and the use of P measurements from the water column and inflow and outflow samples to derive a simple mass balance model for P in the lake. 2. A review of published and unpublished literature on Loweswater highlighted trends in water chemistry since the mid-eighteenth century. Land use and farming practises have changed over the past 200 years which have led to increased nutrient loading to the lake with significant increases occurring in the mid part of the last century. Agricultural intensification is likely to be a significant cause of the problem as well as inadequate septic tank management. Local management efforts, led by the Loweswater Care Project, has sought to reduce the primary sources of nutrients reaching the lake, but total phosphorus (TP) concentrations in the lake remain higher than desired. 3. Temperature and dissolved oxygen (DO) profiling confirmed that the site stratified in summer with major changes in DO occurring below a depth of 8 m. The deeper waters were almost entirely anoxic. During stratification the maximum TP value was recorded at the lake bottom. This is a clear indication that P is being released from the lake bed during summer stratification. 4. Analysis of the stream water from the Dub Beck inflow (data for 2013), shows that P influx remains high enough to explain the elevated lake water P concentrations, despite considerable efforts to reduce catchment P sources. 5. Analysis of the water column P profiles shows that P release from the sediment is only a minor contribution to the P load. While the sediment core data reveals a substantial pool of P in the sediment very little of this should be released each year to the water column. In 2013 it is estimated that more than 90% of the P came from the catchment and only ~10% from the sediment. 6. As with all modelling exercises there are uncertainties inherent in the approach. In this case the model output is based on a single year of input data for the inflow P flux calculations and it would be preferable to have a longer data series to inform the modelling. Inflow fluxes are highly dependent on flow conditions and here, in the absence of flow data from Dub Beck, we used data from a nearby stream. Further, the monthly sampling has resulted in most samples being taken in low flow conditions, thus missing potential storm flow conditions. Finally, stream input information is restricted to Dub Beck, and contributions from the other stream is unknown. 7. Nevertheless, the results from the modelling are clear and on that basis we conclude that the priority is for P loading to the lake to be reduced by better catchment management and that lake manipulation is not warranted. Integrated catchment management supported by modelling together with local stakeholder engagement should provide the most effective means of improving the condition of the lake

    An automated approach to identify scientific publications reporting pharmacokinetic parameters [version 1; peer review: awaiting peer review]

    Get PDF
    Pharmacokinetic (PK) predictions of new chemical entities are aided by prior knowledge from other compounds. The development of robust algorithms that improve preclinical and clinical phases of drug development remains constrained by the need to search, curate and standardise PK information across the constantly-growing scientific literature. The lack of centralised, up-to-date and comprehensive repositories of PK data represents a significant limitation in the drug development pipeline.In this work, we propose a machine learning approach to automatically identify and characterise scientific publications reporting PK parameters from in vivo data, providing a centralised repository of PK literature. A dataset of 4,792 PubMed publications was labelled by field experts depending on whether in vivo PK parameters were estimated in the study. Different classification pipelines were compared using a bootstrap approach and the best-performing architecture was used to develop a comprehensive and automatically-updated repository of PK publications. The best-performing architecture encoded documents using unigram features and mean pooling of BioBERT embeddings obtaining an F1 score of 83.8% on the test set. The pipeline retrieved over 121K PubMed publications in which in vivo PK parameters were estimated and it was scheduled to perform weekly updates on newly published articles. All the relevant documents were released through a publicly available web interface (https://app.pkpdai.com) and characterised by the drugs, species and conditions mentioned in the abstract, to facilitate the subsequent search of relevant PK data. This automated, open-access repository can be used to accelerate the search and comparison of PK results, curate ADME datasets, and facilitate subsequent text mining tasks in the PK domain.</ns4:p

    Transmit Power Minimization for MIMO Systems of Exponential Average BER with Fixed Outage Probability

    Get PDF
    This document is the Accepted Manuscript version of the following article: Dian-Wu Yue, and Yichuang Sun, ‘Transmit Power Minimization for MIMO Systems of Exponential Average BER with Fixed Outage Probability’, Wireless Personal Communications, Vol. 90 (4): 1951-1970, first available online on 20 June 2016. Under embargo. Embargo end date: 20 June 2017. The final publication is available at Springer via https://link.springer.com/article/10.1007%2Fs11277-016-3432-4This paper is concerned with a wireless multiple-antenna system operating in multiple-input multiple-output (MIMO) fading channels with channel state information being known at both transmitter and receiver. By spatiotemporal subchannel selection and power control, it aims to minimize the average transmit power (ATP) of the MIMO system while achieving an exponential type of average bit error rate (BER) for each data stream. Under the constraints on each subchannel that individual outage probability and average BER are given, based on a traditional upper bound and a dynamic upper bound of Q function, two closed-form ATP expressions are derived, respectively, which can result in two different power allocation schemes. Numerical results are provided to validate the theoretical analysis, and show that the power allocation scheme with the dynamic upper bound can achieve more power savings than the one with the traditional upper bound.Peer reviewe

    Submillimeter Studies of Prestellar Cores and Protostars: Probing the Initial Conditions for Protostellar Collapse

    Full text link
    Improving our understanding of the initial conditions and earliest stages of protostellar collapse is crucial to gain insight into the origin of stellar masses, multiple systems, and protoplanetary disks. Observationally, there are two complementary approaches to this problem: (1) studying the structure and kinematics of prestellar cores observed prior to protostar formation, and (2) studying the structure of young (e.g. Class 0) accreting protostars observed soon after point mass formation. We discuss recent advances made in this area thanks to (sub)millimeter mapping observations with large single-dish telescopes and interferometers. In particular, we argue that the beginning of protostellar collapse is much more violent in cluster-forming clouds than in regions of distributed star formation. Major breakthroughs are expected in this field from future large submillimeter instruments such as Herschel and ALMA.Comment: 12 pages, 9 figures, to appear in the proceedings of the conference "Chemistry as a Diagnostic of Star Formation" (C.L. Curry & M. Fich eds.

    Imaging-guided chest biopsies: techniques and clinical results

    Get PDF
    Background This article aims to comprehensively describe indications, contraindications, technical aspects, diagnostic accuracy and complications of percutaneous lung biopsy. Methods Imaging-guided biopsy currently represents one of the predominant methods for obtaining tissue specimens in patients with lung nodules; in many cases treatment protocols are based on histological information; thus, biopsy is frequently performed, when technically feasible, or in case other techniques (such as bronchoscopy with lavage) are inconclusive. Results Although a coaxial system is suitable in any case, two categories of needles can be used: fine-needle aspiration biopsy (FNAB) and core-needle biopsy (CNB), with the latter demonstrated to have a slightly higher overall sensitivity, specificity and accuracy. Conclusion Percutaneous lung biopsy is a safe procedure even though a few complications are possible: pneumothorax, pulmonary haemorrhage and haemoptysis are common complications, while air embolism and seeding are rare, but potentially fatal complications

    A survey on managing users' preferences in ambient intelligence

    Get PDF
    Understanding the importance of preference management in ambient intelligent environments is key to providing systems that are better prepared to meet users' expectations. This survey provides an account of the various ways that preferences have been handled in Artificial Intelligence. Our analysis indicates that most of those techniques lack the ability to handle ambiguity and the evolution of preferences over time. Further exploration shows that argumentation can provide a feasible solution to complement existing work. We illustrate our claim by using an intelligent environment case study

    Time-trend of melanoma screening practice by primary care physicians: A meta-regression analysis

    Get PDF
    Objective. To assess whether the proportion of primary care physicians implementing full body skin examination (FBSE) to screen for melanoma changed over time. Methods. Meta-regression analyses of available data. Data Sources: MEDLINE, ISI, Cochrane Central Register of Controlled Trials. Results. Fifteen studies surveying 10,336 physicians were included in the analyses. Overall, 15%\u201382% of them reported to perform FBSE to screen for melanoma. The proportion of physicians using FBSE screening tended to decrease by 1.72% per year (P =0.086). Corresponding annual changes in European, North American, and Australian settings were 120.68% (P =0.494), 122.02% (P =0.044), and +2.59% (P =0.010), respectively. Changes were not influenced by national guide-lines. Conclusions. Considering the increasing incidence of melanoma and other skin malignancies, as well as their relative potential consequences, the FBSE implementation time-trend we retrieved should be considered a worrisome phenomenon

    Autonomic Modulation and Health-Related Quality of Life among Schizophrenic Patients Treated with Non-Intensive Case Management

    Get PDF
    Schizophrenia is associated with autonomic dysfunction and this may increase cardiovascular mortality. Past studies on autonomic modulation of schizophrenic patients focused on inpatients rather than individuals in a community setting, especially those receiving non-intensive case management (non-ICM). Besides, autonomic modulation and its association with health-related quality of life (HRQoL) in this population remain unexplored.A total of 25 schizophrenic patients treated by non-ICM and 40 healthy volunteers were matched by age, gender and body mass index; smokers were excluded. Between the two groups, we compared the individuals' 5 min resting assessments of heart rate variability and their HRQoL, which was measured using EuroQoL-5D (EQ-5D). Patients with schizophrenia were assessed for psychopathology using the Positive and Negative Syndrome Scale for Schizophrenia (PANSS). We examined the relationship between heart rate variability measurements, HRQoL scores, PANSS scores, and other clinical variables among the schizophrenic patients treated by non-ICM.Compared to the controls, patients with schizophrenia showed a significant impairment of autonomic modulation and a worse HRQoL. Cardiovagal dysfunction among the schizophrenic patients could be predicted independently based on lower educational level and more negative symptoms. Sympathetic predominance was directly associated with anticholinergics use and EQ-5D using a visual analogue scale (EQ-VAS).Patients with schizophrenia treated by non-ICM show a significant impairment of their autonomic function and HRQoL compared to the controls. Since the sympathovagal dysfunction is associated with more negative symptoms or higher VAS score, the treatment of the negative symptoms as well as the monitoring of HRQoL might help to manage cardiovascular risk among these individuals. In addition, EQ-VAS scores must be interpreted more cautiously in such a population

    The effects of Gilles de la Tourette syndrome and other chronic tic disorders on quality of life across the lifespan:a systematic review

    Get PDF
    Gilles de la Tourette syndrome (GTS) and other chronic tic disorders are neurodevelopmental conditions characterized by the presence of tics and associated behavioral problems. Whilst converging evidence indicates that these conditions can affect patients' quality of life (QoL), the extent of this impairment across the lifespan is not well understood. We conducted a systematic literature review of published QoL studies in GTS and other chronic tic disorders to comprehensively assess the effects of these conditions on QoL in different age groups. We found that QoL can be perceived differently by child and adult patients, especially with regard to the reciprocal contributions of tics and behavioral problems to the different domains of QoL. Specifically, QoL profiles in children often reflect the impact of co-morbid attention-deficit and hyperactivity symptoms, which tend to improve with age, whereas adults' perception of QoL seems to be more strongly affected by the presence of depression and anxiety. Management strategies should take into account differences in age-related QoL needs between children and adults with GTS or other chronic tic disorders
    corecore