3,306 research outputs found
DSS-13 26-meter antenna upgraded radiometer system
The Deep Space Station (DSS)-13 26-m antenna radiometer system was upgraded with an IBM-compatible computer-controlled configuration with improved supporting hardware and software. Software was generated to analyze results and correct for antenna mispointing, tropospheric loss, and other observing errors. This total power radiometer configuration provides a prototype for the new DSS-13 34-m antenna. The radiometer system is described in terms of the theory, instrumentation hardware, computer configuration, and operational features and performance. The system is used to obtain antenna efficiency and pointing model data and is useful for radio source calibrations required for radio astronomy. Some recent results are given
Public health training in Europe. Development of European masters degrees in public health.
BACKGROUND: Changing political and economic relations in Europe mean that there are new challenges for public health and public health training. There have been several attempts to develop training at the master's level in public health which is focused on meeting the new needs. These have failed due to being too inflexible to allow participation by schools of public health. METHODS: A project funded by the European Union involving public health trainers has developed a new approach which allows participating schools to retain their national differences and work within local rules and traditions, but which aims to introduce the European dimension into public health training. This paper reports the conclusions of this project. CONCLUSIONS: A network of schools wishing to develop European Master's degrees is being established and other schools offering good quality programmes will be able to join
Polynomial Time Approximation Schemes for All 1-Center Problems on Metric Rational Set Similarities
In this paper, we investigate algorithms for finding centers of a given collection N of sets. In particular, we focus on metric rational set similarities, a broad class of similarity measures including Jaccard and Hamming. A rational set similarity S is called metric if D= 1 - S is a distance function. We study the 1-center problem on these metric spaces. The problem consists of finding a set C that minimizes the maximum distance of C to any set of N. We present a general framework that computes a (1 + Δ) approximation for any metric rational set similarity
Sustained pupil responses are modulated by predictability of auditory sequences
The brain is highly sensitive to auditory regularities and exploits the predictable order of sounds in many situations, from parsing complex auditory scenes, to the acquisition of language. To understand the impact of stimulus predictability on perception, it is important to determine how the detection of predictable structure influences processing and attention. Here we use pupillometry to gain insight into the effect of sensory regularity on arousal. Pupillometry is a commonly used measure of salience and processing effort, with more perceptually salient or perceptually demanding stimuli consistently associated with larger pupil diameters.In two experiments we tracked human listeners' pupil dynamics while they listened to sequences of 50ms tone pips of different frequencies. The order of the tone pips was either random, contained deterministic (fully predictable) regularities (experiment 1, n = 18, 11 female) or had a probabilistic regularity structure (experiment 2, n = 20, 17 female). The sequences were rapid, preventing conscious tracking of sequence structure thus allowing us to focus on the automatic extraction of different types of regularities. We hypothesized that if regularity facilitates processing by reducing processing demands, a smaller pupil diameter would be seen in response to regular relative to random patterns. Conversely, if regularity is associated with heightened arousal and attention (i.e. engages processing resources) the opposite pattern would be expected. In both experiments we observed a smaller sustained (tonic) pupil diameter for regular compared with random sequences, consistent with the former hypothesis and confirming that predictability facilitates sequence processing.SIGNIFICANCE STATEMENTThe brain is highly sensitive to auditory regularities. To appreciate the impact that the presence of predictability has on perception, we need to better understand how a predictable structure influences processing and attention. We recorded listeners' pupil responses to sequences of tones that followed either a predictable or unpredictable pattern, as the pupil can be used to implicitly tap into these different cognitive processes. We found that the pupil showed a smaller sustained diameter to predictable sequences, indicating that predictability eased processing rather than boosted attention. The findings suggest that the pupil response can be used to study the automatic extraction of regularities, and that the effects are most consistent with predictability helping the listener to efficiently process upcoming sounds
Non-invasive screening of breast cancer from fingertip smearsâa proof of concept study
Breast cancer is a global health issue affecting 2.3 million women per year, causing death in over 600,000. Mammography (and biopsy) is the gold standard for screening and diagnosis. Whilst effective, this test exposes individuals to radiation, has limitations to its sensitivity and specificity and may cause moderate to severe discomfort. Some women may also find this test culturally unacceptable. This proof-of-concept study, combining bottom-up proteomics with Matrix Assisted Laser Desorption Ionisation Mass Spectrometry (MALDI MS) detection, explores the potential for a non-invasive technique for the early detection of breast cancer from fingertip smears. A cohort of 15 women with either benign breast disease (nâ=â5), early breast cancer (nâ=â5) or metastatic breast cancer (nâ=â5) were recruited from a single UK breast unit. Fingertips smears were taken from each patient and from each of the ten digits, either at the time of diagnosis or, for metastatic patients, during active treatment. A number of statistical analyses and machine learning approaches were investigated and applied to the resulting mass spectral dataset. The highest performing predictive method, a 3-class Multilayer Perceptron neural network, yielded an accuracy score of 97.8% when categorising unseen MALDI MS spectra as either the benign, early or metastatic cancer classes. These findings support the need for further research into the use of sweat deposits (in the form of fingertip smears or fingerprints) for non-invasive screening of breast cancer
A primary fish gill cell culture model to assess pharmaceutical uptake and efflux:evidence for passive and facilitated transport
AbstractThe gill is the principle site of xenobiotic transfer to and from the aqueous environment. To replace, refine or reduce (3Rs) the large numbers of fish used in in vivo uptake studies an effective in vitro screen is required that mimics the function of the teleost gill. This study uses a rainbow trout (Oncorhynchus mykiss) primary gill cell culture system grown on permeable inserts, which tolerates apical freshwater thus mimicking the intact organ, to assess the uptake and efflux of pharmaceuticals across the gill. Bidirectional transport studies in media of seven pharmaceuticals (propranolol, metoprolol, atenolol, formoterol, terbutaline, ranitidine and imipramine) showed they were transported transcellularly across the epithelium. However, studies conducted in water showed enhanced uptake of propranolol, ranitidine and imipramine. Concentration-equilibrated conditions without a concentration gradient suggested that a proportion of the uptake of propranolol and imipramine is via a carrier-mediated process. Further study using propranolol showed that its transport is pH-dependent and at very low environmentally relevant concentrations (ngLâ1), transport deviated from linearity. At higher concentrations, passive uptake dominated. Known inhibitors of drug transport proteins; cimetidine, MK571, cyclosporine A and quinidine inhibited propranolol uptake, whilst amantadine and verapamil were without effect. Together this suggests the involvement of specific members of SLC and ABC drug transporter families in pharmaceutical transport
Systematic prey preference by introduced mice exhausts the ecosystem on Antipodes Island
For assistance collecting samples in the field the authors thank David Thompson, Erica Sommer, David Boyle and Mark Fraser in summer 2011, Helen Nathan, Terry Greene and Graeme Elliott in winter 2013, Fin Cox in autumn 2016 and Jose Luis Herrera in winter 2016. Thanks to the Department of Conservation, Murihiku, for logistical support, and Hank Haazen and crew of the Tiama for transport. Funding was provided for the summer 2011 expedition by NIWA and winter 2013 expedition by the National Geographic Society (Grant No. 9322-13). Thanks to Stephen Thorpe, Robert Hoare, and John Marris for taxonomic identification of invertebrate samples. Thanks to Surrya Khanam for laboratory sorting, Julie Brown and Anna Kilimnik for stable isotope laboratory analyses and Wendy Nelson for macroalgae identification. JCR is currently funded by the Royal Society of New Zealand Rutherford Discovery Fellowship (Grant No. RDF-UOA1404). TWB is currently funded by the European Union's Horizon 2020 research and innovation programme Marie SkĆodowska-Curie Fellowship (Grant No. 747120). Thanks to Katherine Russell and two anonymous reviewers for feedback on the manuscript. This research was conducted under DOC entry (SO-29716-LND 1011/35) and research (SO-29140-FAU 1011/20) permits, and University of Auckland Animal Ethics Committee approval (R845).Peer reviewedPublisher PD
Assessing the reliability of uptake and elimination kinetics modelling approaches for estimating bioconcentration factors in the freshwater invertebrate, Gammarus pulex
This study considers whether the current standard toxicokinetic methods are an accurate and applicable assessment of xenobiotic exposure in an aquatic freshwater invertebrate. An in vivo exposure examined the uptake and elimination kinetics for eight pharmaceutical compounds in the amphipod crustacean, Gammarus pulex by measuring their concentrations in both biological material and in the exposure medium over a 96 h period. Selected pharmaceuticals included two anti-inflammatories (diclofenac and ibuprofen), two beta-blockers (propranolol and metoprolol), an anti-depressant (imipramine), an anti-histamine (ranitidine) and two beta-agonists (formoterol and terbutaline). Kinetic bioconcentration factors (BCFs) for the selected pharmaceuticals were derived from a first-order one-compartment model using either the simultaneous or sequential modelling methods. Using the simultaneous method for parameter estimation, BCF values ranged from 12 to 212. In contrast, the sequential method for parameter estimation resulted in bioconcentration factors ranging from 19 to 4533. Observed toxicokinetic plots showed statistically significant lack-of-fits and further interrogation of the models revealed a decreasing trend in the uptake rate constant over time for rantidine, diclofenac, imipramine, metoprolol, formoterol and terbutaline. Previous published toxicokinetic data for 14 organic micro-pollutants were also assessed and similar trends were identified to those observed in this study. The decreasing trend of the uptake rate constant over time highlights the need to interpret modelled data more comprehensively to ensure uncertainties associated with uptake and elimination parameters for determining bioconcentration factors are minimised
Can viscous fiber lower glycemic markers in type 2 diabetes?
Review of: Jovanovski E, Khayyat R, Zurbau A, et al. Should viscous fiber supplements be considered in diabetes control? Results from a systematic review and meta-analysis of randomized controlled trials. Diabetes Care. 2019;42:755-766. Published correction appears in Diabetes Care. 2019;42:1604.Can viscous fiber lower glycemic markers in type 2 diabetes? The first meta-analysis to focus on viscous dietary fiber in T2D suggests a potential role for this supplement in improving glycemic control. PRACTICE CHANGER: Unless contraindicated, recommend viscous fiber supplementation to your patients with type 2 diabetes (T2D), in addition to the usual evidence-based standards of care, to improve markers of glycemic control. STRENGTH OF RECOMMENDATION: C: Based on a meta-analysis and systematic review of 28 randomized controlled trials, without discussion of patient-oriented outcomes.Erica S. Meisenheimer, MD, MA; Bob Marshall, MD, MPH, MISM, FAAFP, FAMIA; Samuel M. Tiglao, DO, FAAFP; Tyler S. Rogers, MD; David C. Bury, DO, FAAFP; Michael M. Dickman, DO, FAAFP; Robert C. Oh, MD, MPH, FAAFP (Family Medicine Residency, Madigan Army Medical Center, Joint Base Lewis- McChord, WA)Includes bibliographical reference
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