Objective:To determine the diversity of microbiota associated with different breeding habitats of dengue vector mosquitoes Aedes(Ae.)aegypti and Ae.albopictus and to identify any parasitic,epibiont,pathogenic,competit...Objective:To determine the diversity of microbiota associated with different breeding habitats of dengue vector mosquitoes Aedes(Ae.)aegypti and Ae.albopictus and to identify any parasitic,epibiont,pathogenic,competitive or predatory species.Methods:Sampling was performed from a variety of breeding habitats using dipping,pipetting and siphoning techniques.Microbiota in water samples were preserved using Rose Bengal solution and Lugol's iodine,and were identified.Live samples of microbiota were kept under laboratory conditions to observe any pathogenic or parasitic microbiota interacting with larvae.Results:A total of eleven microbiota species(Canthocamptus staphylinus,Canthocamptus microstaphylinus,Parastenocaris brevipes,Lepadella ovalis,Lepadella patella,Rotatoria rotatoria,Rotatoria macrura,Asplanchna brightwelli,Trichocerca rattus,Euglena variabilis,and Flagilaria capucina)belonging to four(4)phyla(Arthropoda,Rotifera,Euglenozoa,and Ochrophyta)and 8 microbiota species belonged to four phyla(Arthropoda,Rotifera,Euglenozoa,and Ochrophyta)were identified from Ae.aegypti and Ae.albopictus breeding habitats respectively.There was a higher percentage(54.54%)of larval habitats positive for the secondary vector Ae.albopictus than through the primary vector Ae.aegypti in the Gampola urban area indicating higher possibility of transmitting the dengue virus through the secondary vector.However,no pathogenic or parasitic ciliates on mosquito larvae were encountered in the present study.Those findings may be due to sampling maingly from temporary container-type breeding habitats.Conclusions:The relative distribution of microbiota associated with mosquito species differed significantly among Ae.aegypti and Ae.albopictus.The overall findings of this study could help in implementing novel eco-friendly vector-control strategies in the study area.展开更多
Liquid-filled compartment structure consists of a bulk steel plate with matrix blind holes which are filled with liquid and a steel front plate to seal up the liquid with rings and bolts.The liquid-filled compartment ...Liquid-filled compartment structure consists of a bulk steel plate with matrix blind holes which are filled with liquid and a steel front plate to seal up the liquid with rings and bolts.The liquid-filled compartment structure can resist the shaped charge warhead effectively.This paper presents experimental and theoretical investigations of the penetration ability of the residual shaped charge jet emerging from the liquid-filled compartment structure after the penetration process at different impact angles.On the basis of shock wave propagation theory,the influence of the liquid-filled compartment structure on jet stability is analysed.The interferences of the liquid backflow caused by a reflected shock wave and a back plate on jet stability under different impact angles are also examined.In addition,the range of the disturbed velocity segments of the jet at different impact angles and the penetration ability of the residual jet are obtained.A theoretical model is validated against the experimental penetration depths.展开更多
The optical nonlinearity in polycrystalline zinc selenide(ZnSe),excited with 775 nm,1 kHz femtosecond laser pulses was investigated via the nonlinear transmission with material thickness and the Z scan technique.The m...The optical nonlinearity in polycrystalline zinc selenide(ZnSe),excited with 775 nm,1 kHz femtosecond laser pulses was investigated via the nonlinear transmission with material thickness and the Z scan technique.The measured two photon absorption coefficientβwas intensity dependent,inferring that reverse saturated absorption(RSA)is also relevant dur-ing high intensity excitation in ZnSe.At low peak intensity I<5 GW cm^(-2),we findβ=3.5 cm GW^(-1) at 775 nm.The spec-tral properties of the broad blueish two-photon induced fluorescence(460 nm-500 nm)was studied,displaying self-ab-sorption near the band edge while the upper state lifetime was measured to be τ_(e)~3.3 ns.Stimulated emission was ob-served when pumping a 0.5 mm thick polycrystalline ZnSe sample within an optical cavity,confirmed by significant line narrowing fromΔλ=11 nm(cavity blocked)toΔλ=2.8 nm at peak wavelength λ_(p)=475 nm while the upper state life-time also decreased.These results suggest that with more optimum pumping conditions and crystal cooling,polycrystal-line ZnSe might reach lasing threshold via two-photon pumping atλ=775 nm.展开更多
AIM： To determine if inflammatory bowel disease （IBD） is a risk factor for osteoporosis in adult Sri Lankans. METHODS： We identified eligible subjects from among consecutive patients diagnosed with IBD who attende...AIM： To determine if inflammatory bowel disease （IBD） is a risk factor for osteoporosis in adult Sri Lankans. METHODS： We identified eligible subjects from among consecutive patients diagnosed with IBD who attended our outpatient clinic. We included only patients aged between 20 and 70 years. Patients who were pregnant, had significant comorbidity, or were on calcium supplements or treatment for osteoporosis within the past 6 mo, were excluded. Healthy, ageand sex-matched controls were also recruited, in a control to patient ratio of 3：1. Both groups were screened for osteoporosis using peripheral dual energy X-ray absorptiometry scanning. RESULTS： The study population consisted of 111 IBD patients （male：female = 43：68; mean age 42.5 years） and 333 controls （male：female = 129：204; mean age 43.8 years）. The occurrence of osteoporosis among IBD patients （13.5%） was significantly higher than among controls （4.5%） （P = 0.001）. The frequency of osteoporosis was not significantly different between ulcerative colitis （14.45%） and Crohn＇s disease （10.7%）. However, on multivariate analysis, only age （P = 0.001）, menopause （P = 0.024） and use of systemic steroids （P 〈 0.001） were found to be associated independently with the occurrence of osteoporosis, while IBD, severity of disease, number of relapses, duration of illness or treatment other than systemic steroids were not. CONCLUSION： IBD does not appear to be an independent risk factor for the occurrence of osteoporosis in this population. However, the use of systemic steroids was a risk factor.展开更多
The influence of a magnetic field on the stability of a shaped charge jet is experimentally investigated at standoffs of 490,650 and 800 mm.The experimental results without and with the magnetic field are compared in ...The influence of a magnetic field on the stability of a shaped charge jet is experimentally investigated at standoffs of 490,650 and 800 mm.The experimental results without and with the magnetic field are compared in terms of the shaped charge jet form,stability and penetration ability.A theoretical model based on one-dimension fluid dynamics is then developed to assess the depth of penetration of the shaped charge at those three standoffs and magnetic conditions.The results show that the penetration capability can be enhanced in more than 70%by the magnetic field.The theoretical calculations are compared with the experimental results with reasonably good correlation.In addition,the parameters introduced in the theory are discussed together with the experiments at three standoffs studied.展开更多
The computer model for near shore wave propagation,SWAN,was used to study wave climates in Liverpool Bay,northwest England with various input parameters,including bottom friction factor,white capping,wind drag formula...The computer model for near shore wave propagation,SWAN,was used to study wave climates in Liverpool Bay,northwest England with various input parameters,including bottom friction factor,white capping,wind drag formulation and effects of tidal modulations.Results were compared with in-situ measurements and reveal the impacts from these inputs on the predictions of wave height and propagation distributions.In particular,the model results were found very sensitive to different input formulations,and tend to underestimate the wave parameters under storm conditions in comparison with the observations.It is therefore important to further validate the model against detailed field measurements,particularly under large storms that are often of the primary concern.展开更多
Multiple-dimensional water flow in variably saturated soils plays an important role in ecological systems such as irrigation and water uptake by plant roots; its quantitative description is usually based on the Richa...Multiple-dimensional water flow in variably saturated soils plays an important role in ecological systems such as irrigation and water uptake by plant roots; its quantitative description is usually based on the Richards＇ equation. Because of the nonlinearity of the Richards＇ equation and the complexity of natural soils, most practical simulations rely on numerical solutions with the nonlinearity solved by iterations. The commonly used iterations for solving the nonlinearity are Picard and Newton methods with the former converging at first-order rate and the later at second-order rate. A recent theoretical analysis by the authors, however, revealed that for solving the diffusive flow, the classical Picard method is actually a chord-Newton method, converging at a rate faster than first order; its linear convergence rate is due to the treatment of the gravity term. To improve computational efficiency, a similar chord-Newton method as for solving the diffusive term was proposed to solve the gravity term. Testing examples for one-dimensional flow showed significant improvement. The core of this method is to produce a diagonally dominant matrix in the linear system so as to improve the iteration-toiteration stability and hence the convergence. In this paper, we develop a similar method for multiple-dimensional flow and compare its performance with the classical Picard and Newton methods for water flow in soils characterised by a wide range of van Genuchten parameters.展开更多
基金The present research received funds from Department of Zoology and Environmental Management,University of Kelaniya,Sri Lanka.
文摘Objective:To determine the diversity of microbiota associated with different breeding habitats of dengue vector mosquitoes Aedes(Ae.)aegypti and Ae.albopictus and to identify any parasitic,epibiont,pathogenic,competitive or predatory species.Methods:Sampling was performed from a variety of breeding habitats using dipping,pipetting and siphoning techniques.Microbiota in water samples were preserved using Rose Bengal solution and Lugol's iodine,and were identified.Live samples of microbiota were kept under laboratory conditions to observe any pathogenic or parasitic microbiota interacting with larvae.Results:A total of eleven microbiota species(Canthocamptus staphylinus,Canthocamptus microstaphylinus,Parastenocaris brevipes,Lepadella ovalis,Lepadella patella,Rotatoria rotatoria,Rotatoria macrura,Asplanchna brightwelli,Trichocerca rattus,Euglena variabilis,and Flagilaria capucina)belonging to four(4)phyla(Arthropoda,Rotifera,Euglenozoa,and Ochrophyta)and 8 microbiota species belonged to four phyla(Arthropoda,Rotifera,Euglenozoa,and Ochrophyta)were identified from Ae.aegypti and Ae.albopictus breeding habitats respectively.There was a higher percentage(54.54%)of larval habitats positive for the secondary vector Ae.albopictus than through the primary vector Ae.aegypti in the Gampola urban area indicating higher possibility of transmitting the dengue virus through the secondary vector.However,no pathogenic or parasitic ciliates on mosquito larvae were encountered in the present study.Those findings may be due to sampling maingly from temporary container-type breeding habitats.Conclusions:The relative distribution of microbiota associated with mosquito species differed significantly among Ae.aegypti and Ae.albopictus.The overall findings of this study could help in implementing novel eco-friendly vector-control strategies in the study area.
基金This research was supported by the National Natural Science Foundation of China(Grant No.11472115,11872214)the China Scholarship Council(201706845026).
文摘Liquid-filled compartment structure consists of a bulk steel plate with matrix blind holes which are filled with liquid and a steel front plate to seal up the liquid with rings and bolts.The liquid-filled compartment structure can resist the shaped charge warhead effectively.This paper presents experimental and theoretical investigations of the penetration ability of the residual shaped charge jet emerging from the liquid-filled compartment structure after the penetration process at different impact angles.On the basis of shock wave propagation theory,the influence of the liquid-filled compartment structure on jet stability is analysed.The interferences of the liquid backflow caused by a reflected shock wave and a back plate on jet stability under different impact angles are also examined.In addition,the range of the disturbed velocity segments of the jet at different impact angles and the penetration ability of the residual jet are obtained.A theoretical model is validated against the experimental penetration depths.
文摘The optical nonlinearity in polycrystalline zinc selenide(ZnSe),excited with 775 nm,1 kHz femtosecond laser pulses was investigated via the nonlinear transmission with material thickness and the Z scan technique.The measured two photon absorption coefficientβwas intensity dependent,inferring that reverse saturated absorption(RSA)is also relevant dur-ing high intensity excitation in ZnSe.At low peak intensity I<5 GW cm^(-2),we findβ=3.5 cm GW^(-1) at 775 nm.The spec-tral properties of the broad blueish two-photon induced fluorescence(460 nm-500 nm)was studied,displaying self-ab-sorption near the band edge while the upper state lifetime was measured to be τ_(e)~3.3 ns.Stimulated emission was ob-served when pumping a 0.5 mm thick polycrystalline ZnSe sample within an optical cavity,confirmed by significant line narrowing fromΔλ=11 nm(cavity blocked)toΔλ=2.8 nm at peak wavelength λ_(p)=475 nm while the upper state life-time also decreased.These results suggest that with more optimum pumping conditions and crystal cooling,polycrystal-line ZnSe might reach lasing threshold via two-photon pumping atλ=775 nm.
文摘AIM： To determine if inflammatory bowel disease （IBD） is a risk factor for osteoporosis in adult Sri Lankans. METHODS： We identified eligible subjects from among consecutive patients diagnosed with IBD who attended our outpatient clinic. We included only patients aged between 20 and 70 years. Patients who were pregnant, had significant comorbidity, or were on calcium supplements or treatment for osteoporosis within the past 6 mo, were excluded. Healthy, ageand sex-matched controls were also recruited, in a control to patient ratio of 3：1. Both groups were screened for osteoporosis using peripheral dual energy X-ray absorptiometry scanning. RESULTS： The study population consisted of 111 IBD patients （male：female = 43：68; mean age 42.5 years） and 333 controls （male：female = 129：204; mean age 43.8 years）. The occurrence of osteoporosis among IBD patients （13.5%） was significantly higher than among controls （4.5%） （P = 0.001）. The frequency of osteoporosis was not significantly different between ulcerative colitis （14.45%） and Crohn＇s disease （10.7%）. However, on multivariate analysis, only age （P = 0.001）, menopause （P = 0.024） and use of systemic steroids （P 〈 0.001） were found to be associated independently with the occurrence of osteoporosis, while IBD, severity of disease, number of relapses, duration of illness or treatment other than systemic steroids were not. CONCLUSION： IBD does not appear to be an independent risk factor for the occurrence of osteoporosis in this population. However, the use of systemic steroids was a risk factor.
基金National Natural Science Foundation of China(Grant No.11972196)Youth fund of Jiangsu Natural Science Foundation(Grant Nos.BK20190433)National Natural Science Funds for Distinguished Young Scholar of China(Grant No.11702144)to provide fund for conducting experiments.
文摘The influence of a magnetic field on the stability of a shaped charge jet is experimentally investigated at standoffs of 490,650 and 800 mm.The experimental results without and with the magnetic field are compared in terms of the shaped charge jet form,stability and penetration ability.A theoretical model based on one-dimension fluid dynamics is then developed to assess the depth of penetration of the shaped charge at those three standoffs and magnetic conditions.The results show that the penetration capability can be enhanced in more than 70%by the magnetic field.The theoretical calculations are compared with the experimental results with reasonably good correlation.In addition,the parameters introduced in the theory are discussed together with the experiments at three standoffs studied.
基金The Public Science and Technology Research Funds Projects of Ocean under contract Nos 200905001 and 201005019partially sponsored by Engineering and Physics Science Research Council (UK) through DTA training scheme
文摘The computer model for near shore wave propagation,SWAN,was used to study wave climates in Liverpool Bay,northwest England with various input parameters,including bottom friction factor,white capping,wind drag formulation and effects of tidal modulations.Results were compared with in-situ measurements and reveal the impacts from these inputs on the predictions of wave height and propagation distributions.In particular,the model results were found very sensitive to different input formulations,and tend to underestimate the wave parameters under storm conditions in comparison with the observations.It is therefore important to further validate the model against detailed field measurements,particularly under large storms that are often of the primary concern.
文摘Multiple-dimensional water flow in variably saturated soils plays an important role in ecological systems such as irrigation and water uptake by plant roots; its quantitative description is usually based on the Richards＇ equation. Because of the nonlinearity of the Richards＇ equation and the complexity of natural soils, most practical simulations rely on numerical solutions with the nonlinearity solved by iterations. The commonly used iterations for solving the nonlinearity are Picard and Newton methods with the former converging at first-order rate and the later at second-order rate. A recent theoretical analysis by the authors, however, revealed that for solving the diffusive flow, the classical Picard method is actually a chord-Newton method, converging at a rate faster than first order; its linear convergence rate is due to the treatment of the gravity term. To improve computational efficiency, a similar chord-Newton method as for solving the diffusive term was proposed to solve the gravity term. Testing examples for one-dimensional flow showed significant improvement. The core of this method is to produce a diagonally dominant matrix in the linear system so as to improve the iteration-toiteration stability and hence the convergence. In this paper, we develop a similar method for multiple-dimensional flow and compare its performance with the classical Picard and Newton methods for water flow in soils characterised by a wide range of van Genuchten parameters.
