38,625 research outputs found
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XML-based genetic rules for scene boundary detection in a parallel processing environment
Genetic programming is based on Darwinian evolutionary theory that suggests that the best solution for a problem can be evolved by methods of natural selection of the fittest organisms in a population. These principles are translated into genetic programming by populating the solution space with an initial number of computer programs that can possibly solve the problem and then evolving the programs by means of mutation, reproduction and crossover until a candidate solution can be found that is close to or is the optimal solution for the problem. The computer programs are not fully formed source code but rather a derivative that is represented as a parse tree. The initial solutions are randomly generated and set to a certain population size that the system can compute efficiently. Research has shown that better solutions can be obtained if 1) the population size is increased and 2) if multiple runs are performed of each experiment. If multiple runs are initiated on many machines the probability of finding an optimal solution are increased exponentially and computed more efficiently. With the proliferation of the web and high speed bandwidth connections genetic programming can take advantage of grid computing to both increase population size and increasing the number of runs by utilising machines connected to the web. Using XML-Schema as a global referencing mechanism for defining the parameters and syntax of the evolvable computer programs all machines can synchronise ad-hoc to the ever changing environment of the solution space. Another advantage of using XML is that rules are constructed that can be transformed by XSLT or DOM tree viewers so they can be understood by the GP programmer. This allows the programmer to experiment by manipulating rules to increase the fitness of a rule and evaluate the selection of parameters used to define a solution
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Watershed rainfall forecasting using neuro-fuzzy networks with the assimilation of multi-sensor information
The complex temporal heterogeneity of rainfall coupled with mountainous physiographic context makes a great challenge in the development of accurate short-term rainfall forecasts. This study aims to explore the effectiveness of multiple rainfall sources (gauge measurement, and radar and satellite products) for assimilation-based multi-sensor precipitation estimates and make multi-step-ahead rainfall forecasts based on the assimilated precipitation. Bias correction procedures for both radar and satellite precipitation products were first built, and the radar and satellite precipitation products were generated through the Quantitative Precipitation Estimation and Segregation Using Multiple Sensors (QPESUMS) and the Precipitation Estimation from Remotely Sensed Information using Artificial Neural Networks-Cloud Classification System (PERSIANN-CCS), respectively. Next, the synthesized assimilated precipitation was obtained by merging three precipitation sources (gauges, radars and satellites) according to their individual weighting factors optimized by nonlinear search methods. Finally, the multi-step-ahead rainfall forecasting was carried out by using the adaptive network-based fuzzy inference system (ANFIS). The Shihmen Reservoir watershed in northern Taiwan was the study area, where 641 hourly data sets of thirteen historical typhoon events were collected. Results revealed that the bias adjustments in QPESUMS and PERSIANN-CCS products did improve the accuracy of these precipitation products (in particular, 30-60% improvement rates for the QPESUMS, in terms of RMSE), and the adjusted PERSIANN-CCS and QPESUMS individually provided about 10% and 24% contribution accordingly to the assimilated precipitation. As far as rainfall forecasting is concerned, the results demonstrated that the ANFIS fed with the assimilated precipitation provided reliable and stable forecasts with the correlation coefficients higher than 0.85 and 0.72 for one- and two-hour-ahead rainfall forecasting, respectively. The obtained forecasting results are very valuable information for the flood warning in the study watershed during typhoon periods. © 2013 Elsevier B.V
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Electromagnetic Actuated stirring in Microbioreactors enabling easier multiplexing & flexible device design
This paper was presented at the 4th Micro and Nano Flows Conference (MNF2014), which was held at University College, London, UK. The conference was organised by Brunel University and supported by the Italian Union of Thermofluiddynamics, IPEM, the Process Intensification Network, the Institution of Mechanical Engineers, the Heat Transfer Society, HEXAG - the Heat Exchange Action Group, and the Energy Institute, ASME Press, LCN London Centre for Nanotechnology, UCL University College London, UCL Engineering, the International NanoScience Community, www.nanopaprika.eu.The development of a novel electromagnetically (EM) actuated stirring method, for use in
microbioreactors, is reported. Mixing in microbioreactors is critical to ensure even distribution of nutrients to
microorganisms and cells. Magnetically driven stirrer bars or peristaltic mixing are the most commonly
utilised mixing methods employed in completely liquid-filled microbioreactors. However the circular reactor
shape required for mixing with a stirrer bar and frequently used for peristaltically mixed microbioreactors
presents difficulties for bubble-free priming in a microfluidic bioreactor. Moreover the circular shape and the
hardware required for both types of mixing reduces the potential packing density of multiplexed reactors. We
present a new method of mixing, displaying design flexibility by demonstrating mixing in circular and
diamond-shaped reactors and a duplex diamond reactor and fermentation of the gram-positive bacteria S.
carnosus in a diamond-shaped microbioreactor system. The results of the optimisation of this mixing
method for performing fermentations alongside both batch and continuous culture fermentations are
presented
Shaping HR8799's outer dust belt with an unseen planet
HR8799 is a benchmark system for direct imaging studies. It hosts two debris
belts, which lie internally and externally to four giant planets. This paper
considers how the four known planets and a possible fifth planet, interact with
the external population of debris through N-body simulations. We find that when
only the known planets are included, the inner edge of the outer belt predicted
by our simulations is much closer to the outermost planet than recent ALMA
observations suggest. We subsequently include a fifth planet in our simulations
with a range of masses and semi-major axes, which is external to the outermost
known planet. We find that a fifth planet with a mass and semi-major axis of
0.1 and 138au predicts an outer belt that agrees well with ALMA
observations, whilst remaining stable for the lifetime of HR8799 and lying
below current direct imaging detection thresholds. We also consider whether
inward scattering of material from the outer belt can input a significant
amount of mass into the inner belt. We find that for the current age of HR8799,
only 1\% of the mass loss rate of the inner disk can be replenished by
inward scattering. However we find that the higher rate of inward scattering
during the first 10Myr of HR8799 would be expected to cause warm dust
emission at a level similar to that currently observed, which may provide an
explanation for such bright emission in other systems at Myr ages.Comment: 16 pages, 13 figures. Accepted for publication in MNRA
Tissue resolved, gene structure refined equine transcriptome.
BackgroundTranscriptome interpretation relies on a good-quality reference transcriptome for accurate quantification of gene expression as well as functional analysis of genetic variants. The current annotation of the horse genome lacks the specificity and sensitivity necessary to assess gene expression especially at the isoform level, and suffers from insufficient annotation of untranslated regions (UTR) usage. We built an annotation pipeline for horse and used it to integrate 1.9 billion reads from multiple RNA-seq data sets into a new refined transcriptome.ResultsThis equine transcriptome integrates eight different tissues from 59 individuals and improves gene structure and isoform resolution, while providing considerable tissue-specific information. We utilized four levels of transcript filtration in our pipeline, aimed at producing several transcriptome versions that are suitable for different downstream analyses. Our most refined transcriptome includes 36,876 genes and 76,125 isoforms, with 6474 candidate transcriptional loci novel to the equine transcriptome.ConclusionsWe have employed a variety of descriptive statistics and figures that demonstrate the quality and content of the transcriptome. The equine transcriptomes that are provided by this pipeline show the best tissue-specific resolution of any equine transcriptome to date and are flexible for several downstream analyses. We encourage the integration of further equine transcriptomes with our annotation pipeline to continue and improve the equine transcriptome
Brine shrimp lethality of a glutarimide alkaloid from Croton sylvaticus Hochst
No Abstract.The East and Central African Journal of Pharmaceutical Sciences Vol. 8(1) 2005: 3-
An unusual cause of acute abdominal pain – A case presentation
BACKGROUND: In 1983, Graham Hughes described a condition of Antiphospholipid Syndrome in which there was a danger of thrombosis. The condition is readily detectable by blood tests and, once diagnosed; the risk of further thrombosis can be significantly reduced by anticoagulation treatments. Affected groups of patients can be distinguished by a specific blood test – the detection of antiphospholipid antibody (Ref-1). Patients with Hughes syndrome have hypercoaguable state with a markedly increased risk of both arterial and venous thrombosis and there is temporal persistence of antibody positivity. CASE PRESENTATION: A 44-year-old woman was admitted under the acute surgical "take" with left sided abdominal pain radiating to her back. She had a history of borderline thyrotoxicosis in the early 1990s. She was on etonogestrel-releasing implants for contraception and there was no history of previous deep venous thrombosis. She was very tender, locally, over the left side of the abdomen. Investigations showed haemoglobin of 13.2 g/dl, white cell count of 19.9 10*9/L, and platelets 214 10*9/L with neutrophilia. Amylase and renal function tests were found to be normal. Liver function tests were deranged with Gamma GT 244 u/l (twice normal). An abdominal Ultrasound Scan suggested a possible splenic infarction, which was confirmed by a CT scan of her abdomen. Tests were carried out to investigate the possibility of a post thrombotic state. Coagulation risk factors for thrombosis were within the normal limits; Protein S 67 %(60–140), Protein C 103 % (72–146), Antithrombin 3 110 %(80–120) and Activated P C Resistance was 1.9(2.0–4.3). The Hams test was negative but the Anticardiolipin antibody test was positive. IgM level was 52 (normal is up to 10) and IgG was 18.8 (normal is up to 10). She also had border line APC Sensitivity 1.9 (2 to 4.3). Kaolin time 49 sec (70–120) Ktmix 64 sec (70–120), thyroid function test revealed TSH 0.32 mu/L, fT4 20.2 pmol/L (10–25). Subsequent determination of Anticardiolipin antibody was negative. Her symptoms were settled with the use of simple analgesia and she was discharged home with long-term anticoagulation medication. The INR target for long-term anticoagulation was aimed at >3. CONCLUSION: This case presented to us as an acute abdominal pain. Subsequent investigations revealed the presence of splenic infarction. Coagulation risk factors for thrombosis proved negative. Haematological investigations revealed the presence of anticardiolipin antibodies at the first instance but subsequent determinations were negative. Hence, it mimicked Hughes syndrome initially but the criteria for temporal persistence of anticardiolipin antibody was not fulfilled. Unusual surgical presentation of a thrombotic abnormality as abdominal pain due to splenic infarction
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