598 research outputs found

    Infection sequence alters disease severity—Effects of the sequential exposure of two larval trematodes to Polypedates cruciger tadpoles

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    Multiple pathogens coexist in nature, and hence, host species often encounter several pathogens simultaneously. The sequence in which the host encounters the parasites influences interactions between parasites and host pathology. Here, the effects of infection by two cercaria (larvae of trematodes) types, pleurolophocercous cercaria of Acanthostomum burminis and a furcocercous cercaria, on the tadpoles of common hourglass tree frog (Polypedates cruciger) were examined. Ten days posthatch, tadpoles (Gosner stage 27/28) were used for infection exposures. First, in a single infection each cercaria type was introduced to the tadpoles separately. Second, coinfection of the two cercaria was carried out by alternating the sequences of exposure. For all the experiments, appropriate controls were instituted. Tadpoles of all groups exposed to parasites had lower survival levels compared to controls. Among the four groups exposed, the highest survival was observed in the coinfection when furcocercous was introduced first (82.5%). The lowest survival was observed in the coinfection when the A. burminis cercaria was introduced first (65.0%). In the coinfections, when A. burminis was introduced prior to furcocercous, survival of the tadpoles was reduced by 17.0% compared to the exposures of furcocercous prior to A. burminis. Prior infection with A. burminis induced negative effect on the host with an increased infection severity, while prior infection with furcocercous had reduced infection severity than lone exposures. These results suggest that furcocercous infections can be beneficial for hosts challenged with A. burminis provided that A. burminis exposure occurs second. None of the treatments had an effect on the growth of the tadpoles, but lengthening of developmental period was observed in some exposures. All exposed tadpoles developed malformations which were exclusively axial—kyphosis and scoliosis. However, there was no difference in the number of malformed individuals in the single infection (19.0%–25.0%) compared to coinfection (20.0%–22.5%) or between coinfections. The results suggest that the sequence of parasite exposure affects host–parasite interactions and hence the disease outcomes. Understanding the effects of coinfection on disease outcomes for hosts provides insight into disease dynamics

    Superheating Field in Superconductors with Nanostructured Surfaces

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    We report calculations of a dc superheating field Hsh in superconductors with nanostructured surfaces. Numerical simulations of the Ginzburg-Landau (GL) equations were performed for a superconductor with an inhomogeneous impurity concentration, a thin superconducting layer on top of another superconductor, and superconductor-insulator-superconductor (S-I-S) multilayers.The superheating field was calculated taking into account the instability of the Meissner state with a nonzero wavelength along the surface, which is essential for realistic values of the GL parameter κ. Simulations were done for the materials parameters of Nb and Nb3Sn at different values of κ and the mean free paths. We show that the impurity concentration profile at the surface and thicknesses of S-I-S multilayers can be optimized to enhance Hsh above the bulk superheating fields of both Nb and Nb3Sn. For example, a S-I-S structure with 90 nm thick Nb3Sn layer on Nb can boost the superheating field up to ≈ 500 mT, while protecting the SRF cavity from dendritic thermomagnetic avalanches caused by local penetration of vortices

    Staged cost optimization of urban storm drainage systems based on hydraulic performance in a changing environment

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    International audienceUrban flooding causes large economic losses, property damage and loss of lives. The impact of environmental changes mainly, the urbanization and the climatic change leads to increased runoff and increased peak flows which the drainage system must be able to cope with to overcome possible damage and inconveniences caused by the induced flooding. Allowing for detention storage to compliment the capacity of the drainage system network is one of the approaches to reduce urban floods. The traditional practice was to design systems against stationary environmental forcings ? including design rainfall, landuse, etc. Due to the rapid change in climate-environment, this approach is no longer economically viable and safe, and explicit consideration of changes that gradually take place during the life-time of the drainage system is warranted. In this paper, a staged cost optimization tool based on the hydraulic performance of the drainage system is presented. A one dimensional hydraulic model is used for hydraulic evaluation of the network together with a genetic algorithm based optimization tool to determine optimal intervention timings and amounts throughout the lifespan of the drainage network. The model was applied in a case study area in the city of Porto Alegre, Brazil. It was concluded that considerable financial savings and/or additional level of flood-safety can be achieved by approaching the design problem as a staged plan rather than one-off scheme

    Host Resistance to Parasitism: Do Older Tadpoles of Polypedates crucigers bear Higher Resistance towards Pleurolophocercous cercariae?

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    Hosts increase their fitness by increasing resistance when exposed to parasites. In the context of tadpoles, the resistance can be conceived as the ability to protect themselves against parasitism by reducing parasite burden. Here we examined the age dependent resistance of the tadpoles of common hourglass tree frog (Polypedates cruciger), exposed to pleurolopho cercouscercariae (Trematoda: Digenea) under laboratory conditions. Eggs masses of P. cruciger were brought to the laboratory and the tadpoles were raised in glass tanks. Pleurolopho cercouscercariae released from freshwater snail, Melanoides tuberculata were exposed to tadpoles at 10, 20 and 30 days post-hatch (Gosner stages 27, 28/29, and 30/31, respectively) in a dose-dependent manner (10 cercariae per tadpole). After 1h the number of cercariae that could not penetrate the tadpole was counted. The number of cysts, their locations in the host body and the survival of the tadpoles were recorded for five consecutive days post-exposure. Older tadpoles had a higher resistance to parasitism than the younger tadpoles. Overall, a significantly fewer number of cercariae penetrated the older tadpoles compared to the younger ones (10 days old tadpoles=717±2.06; 20 days=666±2.42; 30 days=494±3.01, One way ANOVA, F=24.46; p< 0.001). Moreover, infection at 10 days post-hatch stage resulted in significantly low survival (60.0%; Chi square test,χ2=38.960; p < 0.001) compared to the control, but not in 20 and 30 days post-hatch tadpoles (20 days: 73.3%, 30 days; 93.3%; chi square test p >0.05). An increase in the average number of cysts was observed for all treatments until the second day, after which the numbers decreased. Although, disappearing of cysts over time was higher in older tadpoles than in younger ones, it was not statistically significant compared with the other groups (One way ANOVA, F=1.61; p>0.05). The older tadpoles have the ability to avoid penetration of cercariae and resist the already encysted parasites inside, showing an age dependent resistance by the tadpoles of P. cruciger to pleurolophocercous cercariae.Keywords: Pleurolophocercous cercariae, Polypedates cruciger, Survival, Cysts, Resistanc

    Evaluation Of Retrofitting Options In Urban Drainage Systems Based On Flexibility: A Case Study For Nhieu Loc - Thi Nghe Basin In Ho Chi Minh City

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    Inherent uncertainties are the primary constraints and concerns for any robust urban flood management programme. Selection of better retrofitting options to tackle uncertainties involves the process of evaluating the technical and financial feasibility of a wide range of options. In this paper, we present a case study of a catchment in Ho Chi Minh City, Vietnam, where we apply evolutionary methods to search for optimal retrofitting opportunities to cope with uncertainties. Flexible options such as detention storage at nodes and provision of sustainable drainage systems have been identified. The optimal storage volumes for detention storage at the nodes and optimal coverage areas for sustainable drainage options to prevent flooding in Nhieu Loc – Thi Nghe basin, have been arrived at by integrating optimization techniques and a storm water management model. This case study demonstrates and paves the way for considering combined hydraulic modelling along with an optimization approach as the first step towards incorporating flexibility into urban drainage systems. A Real in Option framework to assess the flexibility is also presente

    Economic Factors and Physical Properties of Finger Joint Timber Product to Promote Effective Utilization of Natural Resources

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    Finger joint (FJ) is one of the most sustainable, eco-friendly and economically valuable concept. It ensures the sustainable utilization of small wood cut pieces which removed as waste. Wood pieces are jointed together using glued box comb finger joint cut. It is a new concept for Sri Lankan furniture industry. Therefore, it is necessary to analyze about economic parameters and physical properties of FJ product to ensure the sustainable utilization of FJ timber products. This study attempted to compare strength, appearance and economic variables such as prices, cost of production and profit of FJ products. Comparison of FJ product (Model: STC B-FJ 0019) with the similar size normal timber products (Model:STC B-132) was done to achieve the objective of the study. Three point bending test was done to evaluate Modulus of Elasticity, Modulus of Rupture and maximum force by using UTM. Timber cooperation laboratory was utilized to evaluate strength properties. According to the results of the statistical analysis, strength reduction for FJ products was significantly high. Strength also varied with timber species. Eucalyptus grandis and Pinus showed the highest strength properties while Teak showed the lowst value. MOE values did not show significant difference (0.224) between Jak, Kumbuk, Teak, Mahogany, Pinus, and E. grandis. Strength on vertical and horizontal FJ cuts did not show significant differences although vertical cut was slightly higher. Timber cost for FJ product showed the lowest because of small cut pieces but finishing material, labour, machinery and factory overheads costs were higher than common furniture. Unit production cost for FJ was Rs.171.91 which is higher compared to the cost of normal furniture of Rs. 147.88. FJ furniture showed the higher price most of the time. Therefore, profitability of FJ furniture was significantly higher than common furniture. The uniqueness and high demand help to increase market price and gain more income for producers. On this context FJ product can be promoted to ensure sustainable utilization of timber. Further, this subject is open for further researchers.Keywords: Finger joint, Strength properties, Satisfactio

    Nonlinear Dynamics and Dissipation of a Curvilinear Vortex Driven by a Strong Time-Dependent Meissner Current

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    We report numerical simulations of large-amplitude oscillations of a trapped vortex line under a strong ac magnetic field H(t)=HsinωtH(t)=H\sin\omega t parallel to the surface. The power dissipated by an oscillating vortex segment driven by the surface ac Meissner currents was calculated by taking into account the nonlinear vortex line tension, vortex mass and a nonlinear Larkin-Ovchinnikov (LO) viscous drag coefficient η(v)\eta(v). We show that the LO decrease of η(v)\eta(v) with the vortex velocity vv can radically change the field dependence of the surface resistance Ri(H)R_i(H) caused by trapped vortices. At low frequencies Ri(H)R_i(H) exhibits a conventional increases with HH, but as ω\omega increases, the surface resistance becomes a nonmonotonic function of HH which decreases with HH at higher fields. The effects of frequency, pin spacing and the mean free path lil_i on the field dependence of Ri(H)R_{i}(H) were calculated. It is shown that, as the surface gets dirtier and lil_i decreases, the anomalous drop of Ri(H) R_{i}(H) with HH shifts to lower fields which can be much smaller than the lower critical magnetic field. Our numerical simulations also show that the LO decrease of η(v)\eta(v) with vv can cause a vortex bending instability at high field amplitudes and frequencies, giving rise to the formation of dynamic kinks along the vortex. Measurements of Ri(H)R_i(H) caused by sparse vortices trapped perpendicular to the surface can offer opportunities to investigate an extreme nonlinear dynamics of vortices driven by strong current densities up to the depairing limit at low temperatures. The behavior of Ri(H)R_i(H) which can be tuned by varying the rf frequency or concentration of nonmagnetic impurities is not masked by strong heating effects characteristic of dc or pulse transport measurements

    Including Information on Overdiagnosis in Shared Decision Making : A Review of Prostate Cancer Screening Decision Aids

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    Publisher Copyright: © The Author(s) 2022.Background. Overdiagnosis is an accepted harm of cancer screening, but studies of prostate cancer screening decision aids have not examined provision of information important in communicating the risk of overdiagnosis, including overdiagnosis frequency, competing mortality risk, and the high prevalence of indolent cancers in the population. Methods. We undertook a comprehensive review of all publicly available decision aids for prostate cancer screening, published in (or translated to) the English language, without date restrictions. We included all decision aids from a recent systematic review and screened excluded studies to identify further relevant decision aids. We used a Google search to identify further decision aids not published in peer reviewed medical literature. Two reviewers independently screened the decision aids and extracted information on communication of overdiagnosis. Disagreements were resolved through discussion or by consulting a third author. Results. Forty-one decision aids were included out of the 80 records identified through the search. Most decision aids (n = 32, 79%) did not use the term overdiagnosis but included a description of it (n = 38, 92%). Few (n = 7, 17%) reported the frequency of overdiagnosis. Little more than half presented the benefits of prostate cancer screening before the harms (n = 22, 54%) and only 16, (39%) presented information on competing risks of mortality. Only 2 (n = 2, 5%) reported the prevalence of undiagnosed prostate cancer in the general population. Conclusion. Most patient decision aids for prostate cancer screening lacked important information on overdiagnosis. Specific guidance is needed on how to communicate the risks of overdiagnosis in decision aids, including appropriate content, terminology and graphical display. Most patient decision aids for prostate cancer screening lacks important information on overdiagnosis. Specific guidance is needed on how to communicate the risks of overdiagnosis.Peer reviewe

    A mobile cloud computing framework integrating multilevel encoding for performance monitoring in telerehabilitation

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    Recent years have witnessed a surge in telerehabilitation and remote healthcare systems blessed by the emerging low-cost wearable devices to monitor biological and biokinematic aspects of human beings. Although such telerehabilitation systems utilise cloud computing features and provide automatic biofeedback and performance evaluation, there are demands for overall optimisation to enable these systems to operate with low battery consumption and low computational power and even with weak or no network connections. This paper proposes a novel multilevel data encoding scheme satisfying these requirements in mobile cloud computing applications, particularly in the field of telerehabilitation. We introduce architecture for telerehabilitation platform utilising the proposed encoding scheme integrated with various types of sensors. The platform is usable not only for patients to experience telerehabilitation services but also for therapists to acquire essential support from analysis oriented decision support system (AODSS) for more thorough analysis and making further decisions on treatment

    Purification of Hemoglobin from the Actinorhizal Root Nodules of Myrica gale L

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