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Search Results: 1 - 10 of 168671 matches for " Olivia E. Saunders "
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Comparison of Raw Dairy Manure Slurry and Anaerobically Digested Slurry as N Sources for Grass Forage Production
Olivia E. Saunders,Ann-Marie Fortuna,Joe H. Harrison,Elizabeth Whitefield,Craig G. Cogger,Ann C. Kennedy,Andy I. Bary
International Journal of Agronomy , 2012, DOI: 10.1155/2012/101074
Abstract: We conducted a 3-year field study to determine how raw dairy slurry and anaerobically digested slurry (dairy slurry and food waste) applied via broadcast and subsurface deposition to reed canarygrass (Phalaris arundinacea) affected forage biomass, N uptake, apparent nitrogen recovery (ANR), and soil nitrate concentrations relative to urea. Annual N applications ranged from 600?kg?N?ha?1 in 2009 to 300?kg?N?ha?1 in 2011. Forage yield and N uptake were similar across slurry treatments. Soil nitrate concentrations were greatest at the beginning of the fall leaching season, and did not differ among slurry treatments or application methods. Urea-fertilized plots had the highest soil nitrate concentrations but did not consistently have greatest forage biomass. ANR for the slurry treatments ranged from 35 to 70% when calculations were based on ammonium-N concentration, compared with 31 to 65% for urea. Slurry ANR calculated on a total N basis was lower (15 to 40%) due to lower availability of the organic N in the slurries. No consistent differences in soil microbial biomass or other biological indicators were observed. Anaerobically digested slurry supported equal forage production and similar N use efficiency when compared to raw dairy slurry. 1. Introduction There is a need for a set of best management practices that addresses how to utilize the growing quantity of reactive nitrogen (N) produced by livestock operations. Animal agriculture in the United States has become more specialized with farms consolidating and growing in size [1]. The number of dairy farms has decreased by 94% since 1960, but the number of animals has remained constant [2]. Animal consolidation has created challenges with respect to on-farm N surplus, waste management and nutrient loading in the environment [3, 4]. Annually in the United States, more than 5800?Mg of manure N is produced [5]. One approach to ameliorate negative environmental impacts associated with animal manures is through adoption of anaerobic digestion technologies to treat farm-generated manures and food processing wastes [6–9]. Digestion of wastes can provide a stable and consistent source of nutrients comparable to inorganic fertilizers such as urea. Anaerobic digestion converts organic carbon into methane used to generate electricity, and it also converts organic N to plant available ammonium ( ), increasing the ratio of /total N in the effluent [10]. Carbon is removed during both the methane production and fiber removal processes, resulting in a smaller C?:?N ratio of the effluent [11]. Therefore, digested
A qualitative study of primary care clinicians' views of treating childhood obesity
Olivia Walker, Mark Strong, Rebecca Atchinson, Joanna Saunders, Jo Abbott
BMC Family Practice , 2007, DOI: 10.1186/1471-2296-8-50
Abstract: We interviewed eighteen practitioners (twelve GPs and six nurses) who worked in general practices contracting with Rotherham Primary Care Trust. Interviews were face to face and semi structured. The transcribed data were analysed using framework analysis.GPs and practice nurses felt that their role was to raise the issue of a child's weight, but that ultimately obesity was a social and family problem. Time constraint, lack of training and lack of resources were identified as important barriers to addressing childhood obesity. There was concern that the clinician-patient relationship could be adversely affected by discussing what was often seen as a sensitive topic. GPs and practice nurses felt ill-equipped to tackle childhood obesity given the lack of evidence for effective interventions, and were sceptical that providing diet and exercise advice would have any impact upon a child's weight.GPs and practice nurses felt that their role in obesity management was centred upon raising the issue of a child's weight, and providing basic diet and exercise advice. Clinicians may find it difficult to make a significant impact on childhood obesity while the evidence base for effective management remains poor. Until the lack of effective interventions is addressed, implementing additional targets (for example through the QOF) may not be effective.Obesity is a complex public health issue representing a major threat to children's health [1]. Forecast projections suggest that by 2010 the proportion of children aged two to 15 who are obese will have risen to 19% in boys, and to 22% in girls [2]. The UK Government has responded by setting targets that aim to "halt the year on year rise in obesity among children aged under 11 by 2010 in the context of a broader strategy to tackle obesity in the population as a whole" [3]. As part of this broader strategy obesity was included in the general practice Quality and Outcomes Framework (QOF) contract for 2006–7 [4]. Under the QOF contract p
Interpolation of Discretely-Sampled Density Fields
Will Saunders,Bill E. Ballinger
Physics , 2000,
Abstract: We present a new technique for the interpolation of discretely-sampled non-negat ive scalar fields across regions of missing data. Any set of basis functions can be used, though the method is fastest when they are close to orthogonal. We sho w how the technique may be efficiently applied when the discrete sampling rate v aries across the field. Regularisation is desirable to avoid over-fitting noisy data, and is necessary when the regions of missing data are larger than the requ ired resolution. We present and investigate methods for such regularisation.
Aggregation-fragmentation model of robust concentration gradient formation
Timothy E Saunders
Quantitative Biology , 2015, DOI: 10.1103/PhysRevE.91.022704
Abstract: Concentration gradients of signaling molecules are essential for patterning during development and they have been observed in both unicellular and multicellular systems. In subcellular systems, clustering of the signaling molecule has been observed. We develop a theoretical model of cluster- mediated concentration gradient formation based on the Becker-Doring equations of aggregation- fragmentation processes. We show that such a mechanism produces robust concentration gradients on realistic time and spatial scales so long as the process of clustering does not significantly stabilize the signaling molecule. Finally, we demonstrate that such a model is applicable to the pom1p subcellular gradient in fission yeast.
Ultrasound-Guided Axillary Block in an Anticoagulated Patient after Heartmate II Implantation  [PDF]
Giuseppe Trunfio, Boris Yaguda, Paul C. Saunders, Dennis E. Feierman
Open Journal of Anesthesiology (OJAnes) , 2014, DOI: 10.4236/ojanes.2014.47022

Objective: This case exemplifies the understanding of the physiological changes associate with 1) Left Ventricular Assist Devices, 2) monitoring challenges associated with Left Ventricular Assist Devices and 3) the usefulness of peripheral nerve blocks in this subset of patients. Case report: A 73-year-old man was scheduled for left wrist arthroscopy and debridement to treat a very painful septic joint. He had undergone Heartmate II Left Ventricular Assist Device implantation uneventfully for Destination Therapy 4 months prior. The patient required maintenance of therapeutic anticoagulation. We elected for an ultrasound-guided axillary block, which limits the risks of vascular injury in presence of high INR. The axillary nerve block enabled us to overcome potential anesthetic problems in a patient with a continuous flow LVAD. Conclusion: The physiologic principles of Left Ventricular Assist Device function should be understood before the initiation of anesthesia. Regional Anesthesiologists can offer a very significant contribution to the safe care of patients with heart failure requiring a continuous flow Left Ventricular Assist Device.

Morphogen Profiles Can Be Optimised to Buffer Against Noise
Timothy E Saunders,Martin Howard
Physics , 2009, DOI: 10.1103/PhysRevE.80.041902
Abstract: Morphogen profiles play a vital role in biology by specifying position in embryonic development. However, the factors that influence the shape of a morphogen profile remain poorly understood. Since morphogens should provide precise positional information, one significant factor is the robustness of the profile to noise. We compare three classes of morphogen profiles (linear, exponential, algebraic) to see which is most precise when subject to both external embryo-to-embryo fluctuations and internal fluctuations due to intrinsically random processes such as diffusion. We find that both the kinetic parameters and the overall gradient shape (e.g. exponential versus algebraic) can be optimised to generate maximally precise positional information.
When it Pays to Rush: Interpreting Morphogen Gradients Prior to Steady-State
Timothy E Saunders,Martin Howard
Quantitative Biology , 2009, DOI: 10.1088/1478-3975/6/4/046020
Abstract: During development, morphogen gradients precisely determine the position of gene expression boundaries despite the inevitable presence of fluctuations. Recent experiments suggest that some morphogen gradients may be interpreted prior to reaching steady-state. Theoretical work has predicted that such systems will be more robust to embryo-to-embryo fluctuations. By analysing two experimentally motivated models of morphogen gradient formation, we investigate the positional precision of gene expression boundaries determined by pre-steady-state morphogen gradients in the presence of embryo-to-embryo fluctuations, internal biochemical noise and variations in the timing of morphogen measurement. Morphogens that are direct transcription factors are found to be particularly sensitive to internal noise when interpreted prior to steady-state, disadvantaging early measurement, even in the presence of large embryo-to-embryo fluctuations. Morphogens interpreted by cell-surface receptors can be measured prior to steady-state without significant decrease in positional precision provided fluctuations in the timing of measurement are small. Applying our results to experiment, we predict that Bicoid, a transcription factor morphogen in Drosophila, is unlikely to be interpreted prior to reaching steady-state. We also predict that Activin in Xenopus and Nodal in zebrafish, morphogens interpreted by cell-surface receptors, can be decoded in pre-steady-state.
An off-axis, wide-field, diffraction-limited, reflective Schmidt Telescope
Will Saunders
Physics , 2010, DOI: 10.1117/12.856351
Abstract: Off-axis telescopes with unobstructed pupils offer great advantages in terms of emissivity, throughput, and diffractionlimited energy concentration. For most telescope designs, implementation of an off-axis configuration imposes enormous penalties in terms of cost, optical difficulty and performance, and for this reason off-axis telescopes are rarely constructed. However, for the reflective Schmidt design, implementation of an off-axis configuration is very straightforward, and involves only a modest optical penalty. Moreover, the reflective Schmidt gets particular benefits, avoiding the obstruction of its large focal plane and support column, and gaining a highly accessible, gravity-invariant prime focus, capable of accommodating very large instrumentation. We present an off-axis f/8 reflective Schmidt design for the proposed 'KDUST' Chinese infrared telescope at Dome A on the Antarctic plateau, which offers simultaneous diffraction-limited NIR imaging over 1 degree, and close to diffraction-limited imaging out to 2 degrees for fibre-fed NIR spectroscopy.
Efficient and affordable catadioptric spectrograph designs for 4MOST and Hector
Will Saunders
Physics , 2014, DOI: 10.1117/12.2055029
Abstract: Spectrograph costs have become the limiting factor in multiplexed fiber-based spectroscopic instruments, because tens of millions of resolution elements (spectral x spatial) are now required. Catadioptric (Schmidt-like) designs allow faster cameras and hence reduced detector costs, and recent advances in aspheric lens production make the overall optics costs competitive with transmissive designs. Classic Schmidt designs suffer from obstruction losses caused by the detector being within the beam. A new catadioptric design puts the detector close to the spectrograph pupil, and hence largely in the shadow of the telescope top-end obstruction. The throughput is competitive with the best transmissive designs, and much better in the Blue, where it is usually most valuable. The design also has milder aspheres and is more compact than classic Schmidts, and avoids most of their operational difficulties.
A fast new catadioptric design for fiber-fed spectrographs
Will Saunders
Physics , 2012, DOI: 10.1117/12.925704
Abstract: The next generation of massively multiplexed multi-object spectrographs (DESpec, SUMIRE, BigBOSS, 4MOST, HECTOR) demand fast, efficient and affordable spectrographs, with higher resolutions (R = 3000-5000) than current designs. Beam-size is a (relatively) free parameter in the design, but the properties of VPH gratings are such that, for fixed resolution and wavelength coverage, the effect on beam-size on overall VPH efficiency is very small. For alltransmissive cameras, this suggests modest beam-sizes (say 80-150mm) to minimize costs; while for catadioptric (Schmidt-type) cameras, much larger beam-sizes (say 250mm+) are preferred to improve image quality and to minimize obstruction losses. Schmidt designs have benefits in terms of image quality, camera speed and scattered light performance, and recent advances such as MRF technology mean that the required aspherics are no longer a prohibitive cost or risk. A new Schmidt/Maksutov-derived design is presented, which differs from previous designs in having the detector package outside the camera, and adjacent to the spectrograph pupil. The telescope pupil already contains a hole at its center, because of the obstruction from the telescope top-end. With a 250mm beam, it is possible to largely hide a 6cm \times 6cm detector package and its dewar within this hole. This means that the design achieves a very high efficiency, competitive with transmissive designs. The optics are excellent, as least as good as classic Schmidt designs, allowing F/1.25 or even faster cameras. The principal hardware has been costed at $300K per arm, making the design affordable.
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