An Improved Differential Evolution Algorithm for Maritime Collision Avoidance Route Planning

High accuracy navigation and surveillance systems are pivotal to ensure efficient ship route planning and marine safety. Based on existing ship navigation and maritime collision prevention rules, an improved approach for collision avoidance route planning using a differential evolution algorithm was developed. Simulation results show that the algorithm is capable of significantly enhancing the optimized route over current methods. It has the potential to be used as a tool to generate optimal vessel routing in the presence of conflicts

Modelling of sediment nutrient fluxes for a pulsed organic load

A sediment model has been developed to simulate the Sediment Oxygen Demand (SOD) and sediment nutrient fluxes after a sudden input of Particulate Organic Matter (POM). Compared with previous sediment models, the main advances are the use of a continuous function to represent the kinetics of POM diagenesis and inclusion of the biomass content in POM diagenesis. Laboratory experiments were also carried out to investigate the SOD dynamics and sediment nutrient fluxes after an input of fish food pellets into the sediment. The simulation results of SOD and nutrient fluxes compared fairly well with the experimental measurements. Copyright © 2011 Inderscience Enterprises Ltd.postprin

Organizing the innovation process : complementarities in innovation networking

This paper contributes to the developing literature on complementarities in organizational design. We test for the existence of complementarities in the use of external networking between stages of the innovation process in a sample of UK and German manufacturing plants. Our evidence suggests some differences between the UK and Germany in terms of the optimal combination of innovation activities in which to implement external networking. Broadly, there is more evidence of complementarities in the case of Germany, with the exception of the product engineering stage. By contrast, the UK exhibits generally strong evidence of substitutability in external networking in different stages, except between the identification of new products and product design and development stages. These findings suggest that previous studies indicating strong complementarity between internal and external knowledge sources have provided only part of the picture of the strategic dilemmas facing firms

On the tortuosity factor of solid phase in solid oxide fuel cell electrodes

2014-2015 > Academic research: refereed > Publication in refereed journalAccepted ManuscriptPublishe

Available transfer capability calculation with post-contingency generation rescheduling/load curtailment

The available transfer capability (ATC) is an important index indicating the remaining transfer capability in the physical transmission network for further commercial activity above existing commitments. In this paper, ATC mathematical model considering post-contingency generation rescheduling and load curtailment is first formulated. Benders decomposition method is then used to partition the ATC model above into a base case master problem and a series of independent subproblems relevant to various contingencies. Finally, an improved parallel solution scheme is employed to improve the convergence. Numerical results on a 4-bus test system show clearly the effectiveness of the presented method and necessity of considering post-contingency generation rescheduling and load curtailment in calculating ATC.published_or_final_versio

Provenance and tectonic setting of the Neoproterozoic Yanbian Group, western Yangtze Block (SW China)

Tectonic evolution of the Yangtze Block of South China during Neoproterozoic time has been a major focus of debate and is important in the reconstruction of the Rodinian supercontinent. The Yanbian Group in the western margin of the Yangtze Block is a well-preserved Neoproterozoic volcanic-sedimentary sequence and provides a rare opportunity to examine the provenance and tectonic setting. It consists of a lower part composed of ∼1500 m thick basaltic lavas and an upper part of ∼3500 m thick flysch deposits. The flysch sequence contains typical deep marine turbidites consisting mainly of fine-grained volcaniclastic sandstones and mudstones, indicating a submarine fan depositional system. Detrital zircon dating yields ages ranging from ca. 865 Ma to 1000 Ma with two peaks at ca. 900 Ma and 920 Ma, respectively. The Yanbian Group is intruded by the ∼860 Ma Guandaoshan dioritic pluton, constraining its depositional age at ca. 870 Ma. The sandstones contain abundant feldspar and lithic fragments with minor amounts of quartz and have an average composition of Q 16F 35L 49, suggesting a proximal source and an undissected to transitional arc setting. The lithic fragments in the sandstones point to andesitic and felsic volcanic rock sources. The sandstones and mudstones have intermediate SiO 2/Al 2O 3 (typically 3-6), high Fe 2O 3 + MgO contents (5-12 wt%), and moderate to high K 2O/Na 2O ratios (generally 0.1-1 and 1-10 for sandstones and mudstones, respectively). In comparison with average upper continental crust, they show strong negative Nb-Ta anomalies, slight depletion of Zr-Hf, La and Th, but moderate enrichment of V, Cr, Ni, and Sc. These rocks show LREE enrichment (La/Yb N = 5.3-7.4) with flat HREE, and pronounced negative Eu anomalies (Eu/Eu * = 0.6-0.74) in chondrite-normalized REE patterns, similar to post-Archean shales. Geochemical data for these rocks suggest an arc setting and intermediate-felsic volcanic source, consistent with a back-arc basin scenario for the basaltic lavas in the lower Yanbian Group. Together with regional geological evidence, the turbidites of the Yanbian Group strongly support a model in which the western margin of the Yangtze Block was a major magmatic arc, active probably from ∼920 Ma to 740 Ma, a period of more than 180 million years. © 2008 Elsevier B.V. All rights reserved.postprin

Magnetoresistance in LaFe11.2Co0.7Si1.1 compound

Magnetoresistance has been studied in LaFe/sub 11.2/Co/sub 0.7/Si/sub 1.1/ compound. The ferromagnetic ordering at Curie temperature T/sub C/ of 274 K was found being accompanied by a drastic negative lattice expansion due to the strong structural and magnetic interplay. Such a simultaneous magnetic and lattice change would cause changes in transport properties. The measured transport properties indicate that the transition can be induced by temperature or applied magnetic field. The sample shows a metallic character below T/sub C/, whereas the electrical resistance decreases dramatically and then recovers the metal-like behavior above T/sub C/. Application of a magnetic field retains the transitions via increasing the ferromagnetic ordering temperature. An isothermal increase of field leads to an increase of resistance at temperatures near but above T/sub C/, which is a result of the field-induced metamagnetic transition from paramagnetic to ferromagnetic state.published_or_final_versio

Transplanted Olfactory Ensheathing Cells Reduce Retinal Degeneration in Royal College of Surgeons Rats

PURPOSE OF THE STUDY: Retinitis pigmentosa (RP) is a group of genetic disorders and a slow loss of vision that is caused by a cascade of retinal degenerative events. We examined whether these retinal degenerative events were reduced after cultured mixtures of adult olfactory ensheathing cells (OECs) and olfactory nerve fibroblasts (ONFs) were transplanted into the subretinal space of 1-month-old RCS rat, a classic model of RP. MATERIALS AND METHODS: The changes in retinal photoreceptors and Müller cells of RCS rats after cell transplantation were observed by the expression of recoverin and glial fibrillary acidic protein (GFAP), counting peanut agglutinin (PNA)-positive cone outer segments and calculating the relative apoptotic area. The retinal function was also evaluated by Flash electroretinography (ERG). To further investigate the mechanisms, by which OECs/ONFs play important roles in the transplanted retinas, nerve growth factor (NGF), brain-derived neurotrophic factor (BDNF), and basic fibroblast growth factor (bFGF) secretion of the cultured cells were analyzed by ELISA. The ability of OECs/ONFs to ingest porcine retinal outer segments and the amount of phagocytosis were compared with retinal pigment epithelium (RPE) cells. RESULTS: Our research showed that the transplantation of OECs/ONFs mixtures restored recoverin expression, protected retinal outer segments, increased PNA-positive cone outer segments, reduced caspase-positive apoptotic figures, downregulated GFAP, and maintained the b-wave of the ERG. Cultured OECs/ONFs expressed and secreted NGF, BDNF, and bFGF which made contributions to assist survival of the photoreceptors. An in vitro phagocytosis assay showed that OECs, but not ONFs, phagocytosed porcine retinal outer segments, and the phagocytic ability of OECs was even superior to that of RPE cells. CONCLUSIONS: These findings demonstrate that transplantation of OECs/ONFs cleaned up the accumulated debris in subretinal space, and provided an intrinsic continuous supply of neurotrophic factors. It suggested that transplantation of OECs/ONFs might be a possible future route for protection of the retina and reducing retinal degeneration in RP

The effect of morphine upon DNA methylation in ten regions of the rat brain

Morphine is one of the most effective analgesics in medicine. However, its use is associated with the development of tolerance and dependence. Recent studies demonstrating epigenetic changes in the brain after exposure to opiates have provided insight into mechanisms possibly underlying addiction. In this study, we sought to identify epigenetic changes in ten regions of the rat brain following acute and chronic morphine exposure. We analyzed DNA methylation of six nuclear-encoded genes implicated in brain function (Bdnf, Comt, Il1b, Il6, Nr3c1 and Tnf) and three mitochondrially-encoded genes (Mtco1, Mtco2 and Mtco3), and measured global 5-methylcytosine (5-mc) and 5-hydroxymethylcytosine (5-hmc) levels. We observed differential methylation of Bdnf and Il6 in the pons, Nr3c1 in the cerebellum, and Il1b in the hippocampus in response to acute morphine exposure (all p<0.05). Chronic exposure was associated with differential methylation of Bdnf and Comt in the pons, Nr3c1 in the hippocampus and Il1b in the medulla oblongata (all p<0.05). Global 5-mc levels significantly decreased in the superior colliculus following both acute and chronic morphine exposure, and increased in the hypothalamus following chronic exposure. Chronic exposure was also associated with significantly increased global 5-hmc levels in the cerebral cortex, hippocampus and hypothalamus, but significantly decreased in the midbrain. Our results demonstrate, for the first time, highly localized epigenetic changes in the rat brain following acute and chronic morphine exposure. Further work is required to elucidate the potential role of these changes in the formation of tolerance and dependence

The fate of the homoctenids (Tentaculitoidea) during the Frasnian-Famennian mass extinction (Late Devonian)

The homoctenids (Tentaculitoidea) are small, conical-shelled marine animals which are amongst the most abundant and widespread of all Late Devonian fossils. They were a principal casualty of the Frasnian-Famennian (F-F, Late Devonian) mass extinction, and thus provide an insight into the extinction dynamics. Despite their abundance during the Late Devonian, they have been largely neglected by extinction studies. A number of Frasnian-Famennian boundary sections have been studied, in Poland, Germany, France, and the United States. These sections have yielded homoctenids, which allow precise recognition of the timing of the mass extinction. It is clear that the homoctenids almost disappear from the fossil record during the latest Frasnian “Upper Kellwasser Event”. The coincident extinction of this pelagic group, and the widespread development of intense marine anoxia within the water column, provides a causal link between anoxia and the F-F extinction. Most notable is the sudden demise of a group, which had been present in rock-forming densities, during this anoxic event. One new species, belonging to Homoctenus is described, but is not formally named here