Asymptotic Analysis of a Stochastic Model of Mosquito-Borne Disease with the Use of Insecticides and Bet Nets

Ross’ epidemic model describing the transmission of malaria uses two classes of infection, one for humans and one for mosquitoes. This paper presents a stochastic extension of a deterministic vector-borne epidemic model based only on the class of human infectious. The consistency of the model is established by proving that the stochastic delay differential equation describing the model has a unique positive global solution. The extinction of the disease is studied through the analysis of the stability of the disease-free equilibrium state and the persistence of the model. Finally, we introduce some numerical simulations to illustrate the obtained results.

R^(3)上具有一般凹凸非线性项的Klein-Gordon-Born-Infeld方程无穷多解的存在性

该文运用临界点理论中的Z_(2)-山路定理得到了R^(3)上具有凹凸非线性项的Klein-Gordon方程和Born-Infeld理论耦合系统无穷多解的存在性.

Assessing the Impacts of Climate Change on Water-Borne Diseases: A Comparative Study on Taltali Upazila of Barguna District

Objectives: To determine the economic challenges brought on by water-borne illnesses as a result of climate change. In addition to identifying potential access to safe drinking water during climate change and potential health hurdles brought on by water-related diseases, it is important to learn how to reduce the spread of water-borne diseases. Methods: A mixed method design was adopted to evaluate this research, and probability sampling, more specifically simple random sampling, was used to select to sample from the target population. The study was conducted in Taltali upazila of the Barguna district, and data was collected from 384 respondents;among them, 5 respondents were selected for the key informant interview. The research project began in June 2022 and was completed in December 2022. Results: 41.4% of respondents said they suffer from dysentery, 22.4% said the expense of treating water-borne diseases has increased as a result of climate change, and 37.8% said they must travel great distances to obtain clean drinking water. Currently, 41.7% of individuals utilize tube-well water, compared to 19.3% five to ten years ago, and 27.4% have been taught that water filtration helps reduce the spread of water-borne diseases. Conclusions: People’s vulnerability to climate change in the study area is a result of factors such as rapid population increase, unequal access to resources, food insecurity, a long distance to collect water, inadequate medical facilities, a lack of poverty, and a weak health system.

High-resolution forward-looking imaging algorithm for missile-borne detectors

Aiming at a novel missile-borne detector in the optional burst height proximity fuze, a self-adaptive high-resolution forward-looking imaging algorithm (SAHRFL-IA) is presented. The echo data are captured by the missile-borne detector in the target regions;thereby the azimuth angulation accuracy at the same distance dimension is improved dynamically. Thus, azimuth information of the targets in the detection area may be obtained accurately. The proposed imaging algorithm breaks through the conventional misconception of merely using azimuth discrimination curves under ideal conditions during monopulse angulation. The real-time echo data from the target region are used to perform error correction for this discrimination curve, and finally the accuracy of the azimuth angulation may reach the optimum at the same distance dimension. A series of experiments demonstrate the validity, reliability and high performance of the proposed imaging algorithm. Azimuth angulation accuracy may reach ten times that of the detection beam width. Meanwhile, the running time of this algorithm satisfies the requirements of missile-borne platforms.

Space luminous environment adaptability of missile-borne star sensor

To solve the problem of stray interference to star point target identification while a star sensor imaging to the sky,a study on space luminous environment adaptability of missile-borne star sensor was carried out.By Plank blackbody radiation law and some astronomic knowledge,irradiancies of the stray at the star sensor working height were estimated.By relative astrophysical and mathematics knowledge,included angles between the star sensor optical axis point and the stray at any moment were calculated.The calculation correctness was verified with the star map software of Stellarium.By combining the upper analysis with the baffle suppression effect,a real-time model for space luminous environment of missile-borne star sensor was proposed.By signal-noise rate(SNR)criterion,the adaptability of missile-borne star sensor to space luminous environment was studied.As an example,a certain type of star sensor was considered when imaging to the starry sky on June 22,2011(the Summer Solstice)and September 20,2011(August 23 of the lunar year,last quarter moon)in Beijing.The space luminous environment and the adaptability to it were simulated and analyzed at the star sensor working height.In each period of time,the stray suppression of the baffle is analyzed by comparing the calculated included angle between the star sensor optical axis point and the stray with the shielded provided by system index.When the included angle is larger than the shielded angle and less than 90°,the stray is restrained by the baffle.The stray effect on star point target identification is analyzed by comparing the irradiancy of 6 magnitude star with that of the stray on star sensor sensitization surface.When the irradiancy of 6 magnitude star is 5 times more than that of the stray,there is no effect on the star point target identification.The simulation results are identical with the actual situation.The space luminous environment of the missile-borne star sensor can be estimated real-timely by this model.The adaptability of the star sensor to space luminous environment can be analyzed conveniently.A basis for determining the relative star sensor indexes,the navigation star chosen strategy and the missile launch window can be provided.

Infinitely Many Solutions and a Ground-State Solution for Klein-Gordon Equation Coupled with Born-Infeld Theory

In this paper, we intend to consider a kind of nonlinear Klein-Gordon equation coupled with Born-Infeld theory. By using critical point theory and the method of Nehari manifold, we obtain two existing results of infinitely many high-energy radial solutions and a ground-state solution for this kind of system, which improve and generalize some related results in the literature.

瞬变电磁虚拟波场层状Green函数Born近似成像方法

瞬变电磁虚拟波场Born近似成像是通过Born近似对瞬变电磁虚拟波场方程进行线性化处理,求取速度扰动量实现成像的方法.Born近似采用半空间Green函数,在背景速度变化较大时成像分辨率较低.因此,本文从虚拟波场出发,建立辐射场与散射场满足的Helmholtz方程,导出层状介质Green函数表达式,将其应用于Born近似中,得到了基于层状介质格林函数的Born近似电导率计算公式和散射场关于速度扰动量的关系式,最终利用速度扰动量实现成像.通过对理论模型的实验计算,验证了利用层状模型Green函数的Born近似成像算法,能够重建地层电阻率分布,改善Born近似虚拟波动方程逆散射反演的垂向分辨率,获得较好的成像效果.对甘肃地区的实际资料处理结果表明,层状介质Green函数的Born近似,是一个精确度较高、稳定性好、有实际应用价值的成像方法.

A Reverse-transcription Recombinase-aided Amplification Assay for the Rapid Detection of the Far-Eastern Subtype of Tick-borne Encephalitis Virus

Objective Tick-borne encephalitis virus(TBEV) is an emerging pathogen in Europe and North Asia that causes tick-borne encephalitis(TBE). A simple, rapid method for detecting TBEV RNA is needed to control this disease. Methods A reverse-transcription recombinase-aided amplification(RT-RAA) assay was developed. This assay can be completed in one closed tube at 39℃ within 30 minutes. The sensitivity and specificity of RT-RAA were validated using non-infectious synthetic RNA representing a fragment of the NS5 region of the wild-type(WT) TBEV genome and the Senzhang strain. Additionally, 10 batches of tick samples were used to evaluate the performance of the RT-RAA assay. Results The analytical limit of detection of the assay was 20 copies per reaction of the TBEV synthetic transcript and 3 plaque-forming units(pfu) per reaction of TBEV titers. With the specific assay, no signal due to other arboviruses was observed. Of the 10 batches of tick samples obtained from the Changbai Mountains of China, three were TBEV-positive, which was consistent with the results of the quantitative real-time PCR assay. Conclusion A rapid, highly sensitive, specific, and easy-to-use method was developed for the detection of the TBEV Far-Eastern subtype.

SEIR Model and Simulation for Vector Borne Diseases

An epidemic model is a simplified means of describing the transmission of infectious diseases through individuals. The modeling of infectious diseases is a tool which has been used to study the mechanisms by which diseases spread, to predict the future course of an outbreak and to evaluate strategies to control an epidemic. Epidemic models are of many types. Here, SEIR model is discussed. We first discuss the basics of SEIR model. Then it is applied for vector borne diseases. Steady state conditions are derived. A threshold parameter R0 is defined and is shown that the disease will spread only if its value exceeds 1. We have applied the basic model to one specific diseases-malaria and did the sensitivity analysis too using the data for India. We found sensitivity analysis very important as it told us the most sensitive parameter to be taken care of. This makes the work more of practical use. Numerical simulation is done for vector and host which shows the population dynamics in different compartments.

Numerical Analysis of Stochastic Vector Borne Plant Disease Model

We are associating the solutions of stochastic and deterministic vector borne plant disease model in this manuscript.The dynamics of plant model depends upon threshold number P^(∗).If P^(∗)<1 then condition helpful to eradicate the disease in plants while P^(∗)>1 explains the persistence of disease.Inappropriately,standard numerical systems do not behave well in certain scenarios.We have been proposed a structure preserving stochastic non-standard finite difference system to analyze the behavior of model.This system is dynamical consistent,positive and bounded as defined by Mickens.

PRELIMINARY STUDIES ON AIR-BORNE SPORES AND POLLENS IN NORTHERN SUBURB OF BEIJING

Air borne spores and pollens were collected by using Durham Pollen Sampler from 38 metre building top platform in northern suburb of Beijing and observations were carried out accordingly. Distributed mainly in March to October in a year, both the amount and variations of pollens are affected by air temperature and precipitation in addition to that of florescence. The maximum pollen species are found in May, and the maximum pollen amount is found in early June, and then in September. Pollens of herbs predominate, mostly distributing in May to September. Xylophytes have smaller amount of pollens which are found mostly in March to June. The amount of air borne plant pollen and bacterial spores is much higher in hot sunny days than in the cloudy/rainy days. The alternation of hot sunny days with cloudy/rainy days is most favourable for bacterial spores dispersion.

微分算子展开与耦合势三维有限体积法快速计算随钻超深前视电阻率测井响应非线性Born逼近

本文将非均质各向异性地层中电磁场耦合势Helmhotz方程分解为各向异性背景场方程与散射场方程,并应用算子展开技术推导出耦合势Born级数解,建立一套三维非均质各向异性地层中随钻超深前视电阻率测井响应各阶散射电磁场与非线性Born逼近的有效计算方法.首先,利用传输线法与二维插值技术确定背景电磁场空间分布,得到零阶Born逼近解,然后根据电磁场耦合势的Born级数解推导出各阶散射电磁场方程与递推关系,通过三维有限体积法实现各阶散射场耦合势方程的离散,在此基础上结合MKL PARDISO并行技术,通过递推方式逐步计算各阶散射电磁场,并根据Born级数部分和确定不同阶次的非线性Born逼近.最后利用数值模拟结果对正演算法加以检验,并深入研究分析各阶散射场的变化特征与Born级数的收敛性质.

Food-borne parasitic zoonosis: Distribution of trichinosis in Thailand

Trichinosis is among the most common food-borne parasitic zoonoses in Thailand and many outbreaks are reported each year. This paper investigates the distribution of the disease in regions of north, north-east, central and south Thailand. Between the earliest recorded of outbreak of trichinosis in Mae Hong Son Province in 1962 and 2006, there have been 135 outbreaks involving 7340 patients and 97 deaths in Thailand. The highest number of cases, 557, was recorded in 1983. Most infected patients were in the 35-44 year age group, and the disease occurred more frequently in men than women during 1962-2003, with no significant sex difference during 2004-2006. Outbreaks were most common in the northern areas, especially in rural areas where raw and under-cooked pork and/or wild animals are eaten. Human infections occur annually in northern Thailand during communal feasts celebrating the Thai New Year. Trichinosis causes have been reported every year, supporting the need for planning education programs.

Fermentation, formulation and evaluation of PGPR Bacillus subtilis isolate as a bioagent for reducing occurrence of peanut soil-borne diseases

Four isolates of Bacillus subtilis coded,B4,B7,B8 and B10 were examined as biocontrol agents for their abilities and antagonistic effect on the in vitro growth of certain phytopathogenic fungi of peanut,Rhizoctonia solani and Sclerotium rolfsii.Bacillus subtilis isolate B4(GenBank accession no.EF150884)was the highly effective one for inhibiting the fungal mycelial growth.Batch fermentation of B.subtilis isolate B4 was carried out and the maximum biomass achieved was 4.53 g L-1 at 11 h.Bacillus subtilis isolate B4 was formulated and evaluated as a biofungicide to reduce peanut soil-borne diseases under greenhouse and field conditions at the side of Rizolex-T(fungicide)as standard.Treatments by formulated plant growth-promoting rhizobacteria(PGPR)B.subtilis B4 and Rizolex-T in a soil infested with R.solani,S.rolfsii and mixture of them were more effective in decreasing percentage of damping-off,root and pod rot disease incidence(%)in greenhouse and open field environment during the two seasons 2015 and 2016.Treatments by PGPR gave highly dry weight and number of healthy pods compared to control of fungi treatment which was nearby to dry weights of healthy pods achieved by treatments by Rizolex-T in a soil infested with S.rolfsii,R.solani and mixture of them.Formulated PGPR B.subtilis B4 gave higher increasing of yield percentage than treatment by Rizolex-T in the two evaluated seasons 2015 and 2016.It can conclude that the produced bioforumlated agent was more efficient as fungicide when compared with the other chemical synthesized fungicides,safe for human and the environment and economy.

Tick-borne encephalitis: A review of epidemiology, clinical characteristics, and management

Tick-borne encephalitis is an infection of central nervous system caused by tick-borne encephalitis virus transmitted to humans predominantly by tick bites. During the last few decades the incidence of the disease has been increasing and poses a growing health problem in almost all endemic European and Asian countries. Most cases occur during the highest period of tick activity, in Central Europe mainly from April to November. Tickborne encephalitis is more common in adults than in children. Clinical spectrum of the disease ranges from mild meningitis to severe meningoencephalitis with or without paralysis. Rare clinical manifestations are an abortive form of the disease and a chronic progressive form. A post-encephalitic syndrome, causing long-lasting morbidity that often affects the quality of life develops in up to 50% of patients after acute tick-borne encephalitis. Clinical course and outcome vary by subtype of tick-borne encephalitis virus(the disease caused by the European subtype has milder course and better outcome than the disease caused by Siberian and Far-Easter subtypes), age of patients(increasing age is associated with less favorable outcome), and host genetic factors. Since clinical features and laboratory results of blood and cerebrospinal fluid are nonspecific, the diagnosis must be confirmed by microbiologic findings. The routine laboratory confirmation of the tick-borne encephalitis virus infection is based mainly on the detection of specific Ig M and Ig G antibodies in serum(and cerebrospinal fluid), usually by enzyme-linked immunosorbent assay. There is no specific antiviral treatment for tick-borne encephalitis. Vaccination can effectively prevent the disease and is indicated for persons living in or visiting tick-borne encephalitis endemic areas.

Dynamics of Rodent and Rodent-borne Disease during Construction of the Three Gorges Reservoir from 1997 to 2012

Objective To investigate the impact of impoundment and active public health interventions on rodent populations and rodent-borne diseases in the Three Gorges reservoir region from 1997 to 2012. Methods Surveillance data from 1997 to 2012 were extracted from the Public Health Surveillance System of The Three Gorges established in 1997. Temporal changes in the incidences of hemorrhagic fever with renal syndrome （HFRS） and leptospirosis, rodent density, pathogen-carrying rates, and their correlations were analyzed. Results The average indoor and outdoor rodent densities decreased overall from 1997 to 2012. The average densities decreased by 47.72% （from 4.38% to 2.29%） and 39.68% （from 4.41% to 2.66%）, respectively, after impoundment （2003-2012） compared with before impoundment （1997-2002）. The average annual incidence rates of HFRS and leptospirosis were 0.29/100,000 and 0.52/100,000, respectively, and decreased by 85.74% （from 0.68/100,000 to 0.10/100,000） and 95.73% （from 1.47/100,000 to 0.06S/100,000）, respectively, after impoundment compared with before impoundment. Incidences of HFRS and leptospirosis appear to be positively correlated with rodent density in the reservoir area. Conclusion This study demonstrated that rodent density and incidences of rodent-borne diseases decreased and were maintained at low levels during construction of the Three Gorges dam. Measures that reduce rodent population densities could be effective in controlling rodent-borne diseases during large-scale hydraulic engineering construction.

A Satellite-borne Miniature Ion Mass Spectrometer for Space Plasma

The miniature design technology is an important trend in space exploration.Mass spectrometer is used extensively in the space environment detection.The miniature ion mass spectrometer utilizes a 127° cylindrical electrostatic analyzer accompanied with a Time of Flight(TOF)unit based on ultrathin carbon foil to measure the energy spectra and composition of space plasma.The Time of Flight technique has been used broadly in space plasma measurement.A new type of miniature method for the ion mass spectrometer is introduced.The total mass of the instrument is1.8 kg and the total power consumption is 2.0 W.The calibration results show that the energy measurement range is 8.71~43550eV,the energy resolution is 1.86%and the ion mass from 1 amu(1 amu= 1.67 × 10^(-27)kg) to 58 amu can be resolved by the miniature mass spectrometer.The miniature ion mass spectrometer also has a potential to be increased in the field of view by an electrostatic deflecting system to extend its application in space plasma detection.The miniature ion mass spectrometer has been selected for pre-study of Chinese Strategic Priority Research Program on Space Science.

Finite element analysis of dynamic response and structure borne noise of gearbox

A dynamic finite element method combined with finite element mixed formula for contact problem is used to analyze the dynamic characteristics of gear system. Considering the stiffness excitation, error excitation and meshing shock excitation, the dynamic finite element model is established for the entire gear system which includes gears, shafts, bearings and gearbox housing. By the software of I-DEAS, the natural frequency, normal mode, dynamic time-domain response, frequency-domain response and one-third octave velocity grade structure borne noise of gear system are studied by the method of theoretical modal analysis and dynamic response analysis. The maximum values of vibration and structure borne noise are occurred at the mesh frequency of output grade gearing.

Spatial Risk Analysis of Water Borne Diseases (Bovine Leptospirosis) in the Rive Nile State-Sudan

Geographical Information Science (GIS) technologies have been used increasingly for ecology and epidemiology of water-borne diseases, providing approach for animal health issues. This study was set up to investigate the geographical distribution of Bovine that was affected by Leptospira hardijo, in River Nile state, on October 2012. Locations of targeted cattle were delimited using GPS. Fifty three (53) of blood samples were collected, and screened in the laboratory for Leptospira hardijo specific antibodies using indirect ELISA. 15.09% had evidence of infection as determined by the presence of anti-leptospira antibodies. It was inferred that no incidences were recorded in 45 locations out of the 53 selected locations in the state. Leptospirosis risk area for transmission was mapped using 5 km buffer distance. Animals’ movements routes were mapped with their contacts area and positive samples locations, hafair locations where animals contacts were mapped. This study demonstrated the value of GIS and GPS in disease mapping for animals’ health, and this might help veterinary authorities to implement strategic interventions for animal disease control.

Space-borne antenna adaptive anti-jamming method based on gradient-genetic algorithm

A novel space-borne antenna adaptive anti-jamming method based on the genetic algorithm （GA）, which is combined with gradient-like reproduction operators is presented, to search for the best weight for pattern synthesis in radio frequency （RF）. Combined, the GA＇s the capability of the whole searching is, but not limited by selection of the initial parameter, with the gradient algorithm＇s advantage of fast searching. The proposed method requires a smaller sized initial population and lower computational complexity. Therefore, it is flexible to implement this method in the real-time systems. By using the proposed algorithm, the designer can efficiently control both main-lobe shaping and side-lobe level. Simulation results based on the spot survey data show that the algorithm proposed is efficient and feasible.