135 research outputs found

    Integration of crosswind forces into train dynamic modelling

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    In this paper a new method is used to calculate unsteady wind loadings acting on a railway vehicle. The method takes input data from wind tunnel testing or from computational fluid dynamics simulations (one example of each is presented in this article), for aerodynamic force and moment coefficients and combines these with fluctuating wind velocity time histories and train speed to produce wind force time histories on the train. This method is fast and efficient and this has allowed the wind forces to be applied to a vehicle dynamics simulation for a long length of track. Two typical vehicles (one passenger, one freight) have been modelled using the vehicle dynamics simulation package ‘VAMPIRE®’, which allows detailed modelling of the vehicle suspension and wheel—rail contact. The aerodynamic coefficients of the passenger train have been obtained from wind tunnel tests while those of the freight train have been obtained through fluid dynamic computations using large-eddy simulation. Wind loadings were calculated for the same vehicles for a range of average wind speeds and applied to the vehicle models using a user routine within the VAMPIRE package. Track irregularities measured by a track recording coach for a 40 km section of the main line route from London to King's Lynn were used as input to the vehicle simulations. The simulated vehicle behaviour was assessed against two key indicators for derailment; the Y/Q ratio, which is an indicator of wheel climb derailment, and the Δ Q/Q value, which indicates wheel unloading and therefore potential roll over. The results show that vehicle derailment by either indicator is not predicted for either vehicle for any mean wind speed up to 20 m/s (with consequent gusts up to around 30 m/s). At a higher mean wind speed of 25 m/s derailment is predicted for the passenger vehicle and the unladen freight vehicle (but not for the laden freight vehicle)

    Evaluation of the impact of urban water systems on railways: The scenario of track flooding caused by a water main burst

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    Failures and disruption scenarios can reveal inherent but little known dependencies that exist between technical infrastructure systems. Whereas the dependencies between infrastructures in their normal state of operation are usually obvious and mutually correlated, interdependencies, when systems are disrupted, show a great deal of variety, depending on the specific scenario. The literature reveals the lack of a proper tool that can evaluate and quantify the scenario of track flooding caused by a water main burst, a cross-sectoral failure that can impact the operation of two urban infrastructure systems: the railways and the water supply. This work presents an approach to investigate the impact of urban water systems on railways and applies it to the case study of the Thameslink railway and Thames Water assets in London. The developed tool can be integrated into city level water supply GIS systems to facilitate the understanding of external risks (transport disruption) caused by an internal failure (water main bursts). Also, the results can help railway system operators facilitate the decision-making process in terms of drainage policy and maintenance activities

    Coapplication of effective microorganisms and nanomagnesium boosts the agronomic, physio-biochemical, osmolytes, and antioxidants defenses against salt stress in Ipomoea batatas

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    The application of bio- and nanofertilizers are undoubtedly opening new sustainable approaches toward enhancing abiotic stress tolerance in crops. In this study, we evaluated the application of effective microorganisms (EMs) of five groups belonging to photosynthetic bacteria, lactic acid bacteria, yeast, actinobacteria, and fermenting fungi combined with magnesium oxide (MgO) nanoparticles (MgO-NP) on the growth and productivity of sweet potato plants grown in salt-affected soils. In two field experiments carried out in 2020 and 2021, we tested the impacts of EMs using two treatments (with vs. without EMs as soil drench) coupled with three foliar applications of MgO-NP (0, 50, and 100 μg ml–1 of MgO, representing MgO-NP0, MgO-NP50, and MgO-NP100, respectively). In our efforts to investigate the EMs:MgO-NP effects, the performance (growth and yield), nutrient acquisition, and physio-biochemical attributes of sweet potatoes grown in salt-affected soil (7.56 dS m–1) were assessed. Our results revealed that salinity stress significantly reduced the growth parameters, yield traits, photosynthetic pigment content (chlorophylls a and b, and carotenoids), cell membrane stability, relative water content, and nutrient acquisition of sweet potatoes. However, the EMs+ and/or MgO-NP-treated plants showed high tolerance to salt stress, specifically with a relatively superior increase when any of the biostimulants were combined. The application of EMs and/or MgO-NP improved osmotic stress tolerance by increasing the relative water content and membrane integrity. These positive responses owed to increase the osmolytes level (proline, free amino acids, and soluble sugars) and antioxidative compounds (non-enzymatic concentration, enzymatic activities, phenolic acid, and carotenoids). We also noticed that soil salinity significantly increased the Na+ content, whereas EMS+ and/or MgO-NP-treated plants exhibited lower Na+ concentration and increased K+ concentration and K+/Na+ ratio. These improvements contributed to increasing the photosynthetic pigments, growth, and yield under salinity stress. The integrative application of EMs and MgO-NP showed higher efficacy bypassing all single treatments. Our findings indicated the potential of coapplying EMs and MgO-NP for future use in attenuating salt-induced damage beneficially promoting crop performance

    Canine respiratory coronavirus employs caveolin-1-mediated pathway for internalization to HRT-18G cells

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    Canine respiratory coronavirus (CRCoV), identified in 2003, is a member of the Coronaviridae family. The virus is a betacoronavirus and a close relative of human coronavirus OC43 and bovine coronavirus. Here, we examined entry of CRCoV into human rectal tumor cells (HRT-18G cell line) by analyzing co-localization of single virus particles with cellular markers in the presence or absence of chemical inhibitors of pathways potentially involved in virus entry. We also targeted these pathways using siRNA. The results show that the virus hijacks caveolin-dependent endocytosis to enter cells via endocytic internalization

    New Mediterranean Biodiversity Records (December 2017)

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    The “New Mediterranean Biodiversity Records” series includes new records of marine species found in the Mediterranean basin and/or information on the spatial distribution of already established species of particular interest. The current article presents information on 20 marine taxa classified per country according to their geographic position in the Mediterranean, from west to east. The new records per ecoregion are as follows: Algeria: the first record of the fish Etrumeus golanii is reported along the Algerian coast. Tunisia: the alien jellyfish Phyllorhiza punctata is reported for the first time in the Gulf of Gabès. Italy: the first record of Siganus rivulatus in the Strait of Sicily and a new record of Katsuwonus pelamis from the central Tyrrhenian Sea are reported. The establishment of the isopod of the genus Mesanthura in the northern Tyrrhenian with some notes on its ecology are also included. Croatia: signs of establishment of the Lessepsian Siganus luridus and the occurrence of the alien mollusc Rapana venosa are reported. Albania: the first record of the elasmobranch Alopias superciliosus and a recent sighting of the rare monk seal Monachus monachus in Albanian waters are given. Greece: signs of the establishment of the fish Parupeneus forsskali and of the ascidian Hermania momus in Hellenic Aegean waters are reported. Turkey: a new record of the fish P. forsskali and of the Acarea of the genus Acaromantis and Simognathus are given, while the first case of Remora australis in association with delphinids and the occurrence of the sea star Coscinasterias tenuispina are reported. Also, the establishment of the two alien species Isognomon legumen and Viriola sp. [cf. corrugata] are presented. Egypt: the fish Bathygobius cyclopterus is reported for the first time in Mediterranean Sea waters. Also, a new record of Pagellus bogaraveo and a first record of Seriola fasciata in Egyptian Mediterranean waters are reported. Lebanon: the first record of Dondice banyulensis is presented

    Soil application of effective microorganisms and nitrogen alleviates salt stress in hot pepper (Capsicum annum L.) plants

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    The application of effective microorganisms (EMs) and/or nitrogen (N) have a stimulating effect on plants against abiotic stress conditions. The aim of the present study was to determine the impact of the co-application of EMs and N on growth, physio-biochemical attributes, anatomical structures, nutrients acquisition, capsaicin, protein, and osmoprotectant contents, as well as the antioxidative defense system of hot pepper (Capsicum annum L.) plants. In the field trials, EMs were not applied (EMs-) or applied (EMs+) along with three N rates of 120, 150, and 180 kg unit N ha-1 (designated as N120, N150, and N180, respectively) to hot pepper plants grown in saline soils (9.6 dS m-1). The application of EMs and/or high N levels attenuated the salt-induced damages to hot pepper growth and yield. The application of EMs+ with either N150 or N180 increased the number, average weight and yield of fruits by 14.4 or 17.0%, 20.8 or 20.8% and 28.4 or 27.5%, respectively, compared to hot pepper plants treated with the recommended dose (EMs- × N150). When EMs+ was individually applied or combined with either N150 or N180, increased accumulation of capsaicin were observed by 16.7 or 20.8%, protein by 12.5 or 16.7%, proline by 19.0 or 14.3%, and total soluble sugars by 3.7 or 7.4%, respectively, in comparison with those treated with the integrative EMs- × N150. In addition, the non-enzymatic contents (ascorbate, and glutathione) and enzymatic activities (catalase, superoxide dismutase, and glutathione reductase) of the antioxidant defense systems significantly increased in hot pepper plants treated with EMs+ alone or combined with N150 or N180 under salt stress conditions. Higher accumulation of nutrients (N, P, K+, and Ca2+) along with reduced Na+ acquisition was also evidenced in response to EMs+ or/and high N levels. Most anatomical features of stems and leaves recovered in hot pepper plants grown in saline soils and supplied with EMs+ and N. The application of EMs and N is undoubtedly opening new sustainable approaches toward enhancing abiotic stress tolerance in crops (e.g. hot pepper)

    MEDLEM database, a data collection on large elasmobranchs in the Mediterranean and Black Seas

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    The Mediterranean Large Elasmobranchs Monitoring (MEDLEM) database contains more than 3,000 records (with more than 4,000 individuals) of large elasmobranch species from 21 different countries around the Mediterranean and Black seas, observed from 1666 to 2017. The principal species included in the archive are the devil ray (1,868 individuals), the basking shark (935 individuals), the blue shark (622 individuals), and the great white shark (342 individuals). In the last decades, other species such as the thresher shark (187 individuals), the shortfin mako (180 individuals), and the spiny butterfly ray (138) were reported with increasing frequency. This was possibly due to increased public awareness on the conservation status of sharks, and the consequent development of new monitoring programs. MEDLEM does not have homogeneous reporting coverage throughout the Mediterranean and Black seas and it should be considered as a database of observed species presence. Scientific monitoring efforts in the south-eastern Mediterranean and Black seas are generally lower than in the northern sectors and the absence of some species in our database does not imply their actual absence in these regions. However, the available data allowed us to analyse the frequency and spatial distribution of records, the size frequencies for a few selected the available data allowed us to analyse the frequency and spatial distribution of records, the size frequencies for a few selected species, the overall area coverage, and which species are involved as bycatch by different fishing gears

    Bacteria-inducing legume nodules involved in the improvement of plant growth, health and nutrition

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    Bacteria-inducing legume nodules are known as rhizobia and belong to the class Alphaproteobacteria and Betaproteobacteria. They promote the growth and nutrition of their respective legume hosts through atmospheric nitrogen fixation which takes place in the nodules induced in their roots or stems. In addition, rhizobia have other plant growth-promoting mechanisms, mainly solubilization of phosphate and production of indoleacetic acid, ACC deaminase and siderophores. Some of these mechanisms have been reported for strains of rhizobia which are also able to promote the growth of several nonlegumes, such as cereals, oilseeds and vegetables. Less studied are the mechanisms that have the rhizobia to promote the plant health; however, these bacteria are able to exert biocontrol of some phytopathogens and to induce the plant resistance. In this chapter, we revised the available data about the ability of the legume nodule-inducing bacteria for improving the plant growth, health and nutrition of both legumes and nonlegumes. These data showed that rhizobia meet all the requirements of sustainable agriculture to be used as bio-inoculants allowing the total or partial replacement of chemicals used for fertilization or protection of crops
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