Real life phenomena found in various fields such as engineering, physics,
biology and communication theory can be modeled as nonlinear higher order ordinary
differential equations, particularly the Duffing oscillator. Analytical solutions for these
differential equations can be time consuming whereas, conventional numerical solutions
may lack accuracy. This research propose a block multistep method integrated with a
variable order step size (VOS) algorithm for solving these Duffing oscillators directly.
The proposed VOS Block method provides an alternative numerical solution by reducing
computational cost (time) but without loss of accuracy. Numerical simulations
are compared with known exact solutions for proof of accuracy and against current
numerical methods for proof of efficiency (steps taken).
Replicated linear functional relationship model is often used to describe
relationships between two circular variables where both variables have error terms and
replicate observations are available. We derive the estimate of the rotation parameter
of the model using the maximum likelihood method. The performance of the proposed
method is studied through simulation, and it is found that the biasness of the estimates
is small, thus implying the suitability of the method. Practical application of the
method is illustrated by using a real data set.
MeSH terms: Rotation; Likelihood Functions; Linear Models
It has come to attention that Malaysia have been aiming to build its own
nuclear power plant (NPP) for electricity generation in 2030 to diversify the national
energy supply and resources. As part of the regulation to build a NPP, environmental
risk assessment analysis which includes the atmospheric dispersion assessment has to
be performed as required by the Malaysian Atomic Energy Licensing Board (AELB)
prior to the commissioning process. The assessment is to investigate the dispersion of
radioactive effluent from the NPP in the event of nuclear accident. This article will focus
on current development of locally developed atmospheric dispersion modeling code
based on Gaussian Plume model. The code is written in Fortran computer language
and has been benchmarked to a readily available HotSpot software. The radionuclide
release rate entering the Gaussian equation is approximated to the value found in the
Fukushima NPP accident in 2011. Meteorological data of Mersing District, Johor of
year 2013 is utilized for the calculations. The results show that the dispersion of radionuclide
effluent can potentially affect areas around Johor Bahru district, Singapore
and some parts of Riau when the wind direction blows from the North-northeast direction.
The results from our code was found to be in good agreement with the one
obtained from HotSpot, with less than 1% discrepancy between the two.
An accurate forecasting of tropospheric ozone (O3) concentration is benefi-
cial for strategic planning of air quality. In this study, various forecasting techniques are
used to forecast the daily maximum O3 concentration levels at a monitoring station
in the Klang Valley, Malaysia. The Box-Jenkins autoregressive integrated movingaverage
(ARIMA) approach and three types of neural network models, namely, backpropagation
neural network, Elman recurrent neural network and radial basis function
neural network are considered. The daily maximum data, spanning from 1 January
2011 to 7 August 2011, was obtained from the Department of Environment, Malaysia.
The performance of the four methods in forecasting future values of ozone concentrations
is evaluated based on three criteria, which are root mean square error (RMSE),
mean absolute error (MAE) and mean absolute percentage error (MAPE). The findings
show that the Box-Jenkins approach outperformed the artificial neural network
methods.
A new method to construct the distinct Hamiltonian circuits in complete
graphs is called Half Butterfly Method. The Half Butterfly Method used the concept
of isomorphism in developing the distinct Hamiltonian circuits. Thus some theoretical
works are presented throughout developing this method.
In this paper, we propose a method how to manage the convergence of
Newton’s method if its iteration process encounters a local extremum. This idea establishes
the osculating circle at a local extremum. It then uses the radius of the
osculating circle also known as the radius of curvature as an additional number of
the local extremum. It then takes that additional number and combines it with the
local extremum. This is then used as an initial guess in finding a root near to that
local extremum. This paper will provide several examples which demonstrate that the
proposed idea is successful and they perform to fulfill the aim of this paper.
In this paper, the application of the method of lines (MOL) to the Forced
Korteweg-de Vries-Burgers equation with variable coefficient (FKdVB) is presented.
The MOL is a powerful technique for solving partial differential equations by typically
using finite-difference approximations for the spatial derivatives and ordinary differential
equations (ODEs) for the time derivative. The MOL approach of the FKdVB
equation leads to a system of ODEs. The solution of the system of ODEs is obtained
by applying the Fourth-Order Runge-Kutta (RK4) method. The numerical solution
obtained is then compared with its progressive wave solution in order to show the
accuracy of the MOL method.
The constraint of two ordered extreme minima random variables when one
variable is consider to be stochastically smaller than the other one has been carried
out in this article. The quantile functions of the probability distribution have been
used to establish partial ordering between the two variables. Some extensions and
generalizations are given for the stochastic ordering using the important of sign of the
shape parameter.
Medical diagnosis is the extrapolation of the future course and outcome of a disease and a sign of the likelihood of recovery from that disease. Diagnosis is important because it is used to guide the type and intensity of the medication to be administered to patients. A hybrid intelligent system that combines the fuzzy logic qualitative approach and Adaptive Neural Networks (ANNs) with the capabilities of getting a better performance is required. In this paper, a method for modeling the survival of diabetes patient by utilizing the application of the Adaptive NeuroFuzzy Inference System (ANFIS) is introduced with the aim of turning data into knowledge that can be understood by people. The ANFIS approach implements the hybrid learning algorithm that combines the gradient descent algorithm and a recursive least square error algorithm to update the antecedent and consequent parameters. The combination of fuzzy inference that will represent knowledge in an interpretable manner and the learning ability of neural network that can adjust the membership functions of the parameters and linguistic rules from data will be considered. The proposed framework can be applied to estimate the risk and survival curve between different diagnostic factors and survival time with the explanation capabilities.
In the recent economic crises, one of the precise uniqueness that all stock
markets have in common is the uncertainty. An attempt was made to forecast future
index of the Malaysia Stock Exchange Market using artificial neural network (ANN)
model and a traditional forecasting tool – Multiple Linear Regressions (MLR). This
paper starts with a brief introduction of stock exchange of Malaysia, an overview of
artificial neural network and machine learning models used for prediction. System
design and data normalization using MINITAB software were described. Training
algorithm, MLR Model and network parameter models were presented. Best training
graphs showing the training, validation, test and all regression values were analyzed.
Dengue fever (DF) is currently one of the most important mosquito-borne diseases
that affects humans. Dengue fever (DF) and dengue hemorrhagic fever (DHF) are caused by
four serotypes of dengue viruses (DENV-1 to DENV-4). The main vector transmitting dengue
is Aedes aegypti while Aedes albopictus acts as a secondary vector. As treatment is unavailable
and the first dengue vaccine approved in Mexico, Dengvaxia® has yet to be accepted worldwide,
prevention of the disease relies heavily on surveillance and control of mosquito vectors.
A transgene driver, Wolbachia was found to limit the transmission of dengue virus in Aedes
mosquitoes. Wolbachia alone was able to inhibit viral replication, dissemination and
transmission in A. aeygpti mosquitoes in experimental studies. In A. albopictus, Wolbachia
did not affect the replication of dengue virus but was able to reduce the viral infection of
mosquito salivary glands and limit transmission. Studies on Wolbachia have all been carried
out in adult Aedes mosquitoes, hence this study was conducted to determine the presence of
dengue virus serotypes and Wolbachia in A. aegypti and A. albopictus larvae collected from
ovitraps in four localities in Kuala Lumpur viz. Happy Gardens, IMU Bukit Jalil, Ampang and
Taman Yarl. Another objective of this study was to determine the association between dengue
virus serotypes and the presence of Wolbachia in A. aegypti and A. albopictus larvae. A total
of 300 mosquito larvae was collected; 99 (Happy Gardens), 85 (Bukit Jalil), 73 (Ampang) and
43 (Taman Yarl). Out of 300 larvae collected, 284 were identified as A. albopictus and 16
others were identified as A. aegypti. Of the 284 A. albopictus larvae collected, 211 (74.3%)
and 73 (25.7%) were found to be negative and positive for dengue virus respectively. The
dengue serotypes detected were 2 DENV-2 (2.7%), 58 DENV-3 (79.5%) and 13 DENV-4 (17.8%).
DENV-1 was not detected in any of the A. albopictus larvae. For A. aegypti, out of 16 A.
aegypti larvae collected, 12 (75%) were found to be negative and 4 (25%) were positive for
DENV-2. For the detection of Wolbachia in A. albopictus, 71 out of 284 (25%) and 213 (75%)
larvae were found to be positive and negative for Wolbachia respectively. For A. aegypti, 4
(25%) and 12 (75%) out of 16 larvae were positive and negative for Wolbachia respectively.
This is the first report of Wolbachia in A. albopictus and A. aegypti larvae in Malaysia. A chisquare
test analysis to determine the association between dengue virus and Wolbachia in A.
albopictus and A. aegypti larvae collected from the four localities in Kuala Lumpur showed
that there was no association (χ2 = 3.080; df = 1; P > 0.05).
Anaplasma and Ehrlichia species are important bacterial pathogens of various
animal species including dogs and humans. They constitute a major health problem worldwide,
especially in the tropics and sub-tropics. In order to identify the prevalence of Anaplasma
and Ehrlichia sp. from dogs in the selected area, a total of 100 randomly selected clinically
healthy rescued dogs from animal shelters in Sarawak and Sabah, East Malaysia (50 dogs per
State) were used for this study. Whole blood was collected from these dogs and screened for
presence of Anaplasma and Ehrlichia spp. using polymerase chain reaction (PCR) and
commercial ELISA test (SNAP 4Dx® Plus) for detection of antigen and antibody against the
two pathogens respectively. 27% (A. platys) and 33% (E. canis) of the sampled population
were positive using PCR; while the serological prevalence was 29% for Anaplasma sp. and
55% for Ehrlichia sp. The results of this investigation revealed that stray dogs are potential
reservoir hosts of Anaplasma and Ehrlichia sp. infection with a high prevalence in the area.
The high prevalence rates detected highlights the urgent need to address the growing
population of possible vectors and reservoirs for transmission in the region and also to look
into the public health aspect of the disease.
The essential oils of Litsea elliptica, Piper aduncum, and Piper sarmentosum
were prepared as repellents in gel formulation, and their repellent properties against Aedes
aegypti were experimentally investigated. The lowest effective doses against adult mosquitoes
were 0.8%, 0.5%, and 0.4% for Lit. elliptica, P. sarmentosum and P. aduncum, respectively. In
laboratory testing with human subjects, all three gels provided over 90.0% repellency at one
hour after application and over 80.0% repellency at four hours, compared with 100% and
95.8% protection after one and four hours, respectively, by DEET. In the field, gels with ED95
concentrations of Lit. elliptica, P. aduncum, and P. sarmentosum essential oils provided
99.3%, 97.5%, and 100% protection, respectively, at two hours. The physical properties and
biological stability of the three repellents after storage in hot and cold conditions were also
compared. In conclusion, all three gels have the potential for development as repellents
against Ae. aegypti.
Leptospirosis is a zoonotic disease caused by the pathogenic strains of Leptospira.
Outbreaks of leptospirosis have been reported following water sports events and floods
particularly in men. The symptoms range from mild acute febrile illness to severe form with
multi organ failure. Severe leptospirosis increases the likelihood of mortality and may require
medical interventions in the form of dialysis and/or mechanical ventilation. It is important to
predict severe leptospirosis to optimize medical care since non-severe patients reported to
progress to severe form during the immune phase of the illness. The exaggerated host immune
response causing endothelial and organ damages was shown to be associated with disease
severity and mortality. This review presents the association of immune and endothelial
activation markers, biochemical and genetic markers with disease severity in leptospirosis.
Echinococcus multilocularis is a tiny devastating worm that causes alveolar
echinococcosis in humans. This disease mainly occurs in the liver but rarely in other organs.
We report the subcutaneous encystment of E. multilocularis metacestodes in experimentally
infected mice. Subcutaneous cysts had remarkably fewer protoscoleces (2.05 ± 1.47, n = 20)
and small irregular-shape vesicles (ISVs) in the lumen as compared to liver cysts (69.6 ±
55.65, n = 10). Moreover, abnormal development of a protoscolex was also observed in a
subcutaneous cyst. The results suggest that subcutaneous encystment may have potential
adverse effects on the reproductivity and development of protoscoleces, providing potential
explanations for high tissue preference of metacestode encystment.
In order to understand the epidemiological status of alveolar and cystic
echinococcosis in intermediate and definitive hosts in Qinghai Province, China, during the
period 2007–2011, we investigated the infection in humans and animals, including yaks,
Tibetan sheep, Tibetan dogs, and wild foxes distributed in different counties around the
province. Sera from local residents were examined using a rapid serodiagnostic kit to detect
specific antibodies against Echinococcus. Seropositive samples were confirmed with B-scan
ultrasonography and X-ray examinations. Yaks and Tibetan sheep were checked at
slaughterhouses, and cysts and suspicious lesions were collected for analysis. A rapid diagnostic
strip was used to detect Echinococcus adults in Tibetan dogs. Positive dogs were dewormed
and the parasites collected. Wild foxes were trapped and necropsies performed with particular
attention to the intestine. Forty-eight of 735 (6.4%) humans tested were positive and 475 of
854 (55.6%) Tibetan sheep and 85 of 352 (24.15%) yaks were infected with Echinococcus.
Across different counties, 214 of 948 (22.57%) Tibetan dogs were positive, and five of 36
(13.9%) wild foxes were infected with Echinococcus. Molecular studies showed that all the
infections detected in humans, domestic yaks, and Tibetan sheep were the G1 genotype (E.
granulosus), whereas the parasites from Tibetan foxes and Tibetan dogs were E. shiquicus
and E. multilocularis, respectively. In conclusion, Echinococcosis is hyperendemic in Qinghai
Province in both its intermediate and definitive hosts and the G1 genotype of cystic
Echinococcus is the dominant strain.
A 43-year-old male residing in Prachin Buri Province, Thailand, was admitted to the
Siriraj University Hospital of Mahidol University, Thailand, in July 2014 with right eyelid
swelling and serpiginous lesion for three weeks. A nematode specimen was accidentally
recovered from his upper right eyelid area. The body of the worm was cylindrical and measured
11.0 × 1.4 mm. The head bulb had eight circles of transverse spines. Anterior half of the body
was covered with rows of comb-like pointed spines. The tail part was rounded dorsally and
flattened ventrally and no copulatory spicule was observed at the posterior end. It was
morphologically identified as an immature female worm of gnathostome species. Sequence
analysis for partial cytochrome c oxidase subunit I (COI) gene revealed this recovered
nematode as Gnathostoma spinigerum.
MeSH terms: Accidents; Animals; Electron Transport Complex IV; Edema; Female; Gnathostoma; Head; Hospitals, University; Male; Thailand
Thermal application of a synergized pyrethroid formulation containing 0.8% w/w sbioallethrin,
18.7% w/w permethrin and 16.8% w/w piperonyl butoxide was performed to
evaluate its efficacy against adult and larva of Aedes aegypti and Culex quinquefasciatus.
Three cages each containing 15 mosquitoes and paper cups each containing 25 larvae in 250
ml of water were deployed at each test point between 3 and 20 feet. The formulation was
diluted (formulation:water) 1:33, 1:50 and 1:100, respectively, and applied using a thermal
fogger. Sixty minutes post spraying, the adult knock down rate of Ae. aegypti and Cx.
quinquefasciatus at a maximum distance of 15 feet using all dilution ratios ranged from
96.67 – 100% and 43.33 – 100%, respectively. More than 70.00% adult mortalities were recorded
for both mosquito species at the distance between 3 feet and 15 feet 24 hours post spraying.
In contrast, complete larval mortalities of Ae. aegypti were obtained at a maximum distance
of 10 feet with dilution ratio of 1:33, while more than 80.00% larval mortalities were observed
for Cx. quinquefasciatus at similar maximum distance using all dilution ratios. These results
showed that thermal application using synergized pyrethroid formulation was effective against
both mosquito species tested especially the adult stage.
A serological survey of pig cysticercosis was conducted in a hill-tribe village at
Thai-Myanmar border, Tak province of Thailand in 2012. Sixteen backyard pigs were examined
for pig cysticercosis and gastrointestinal helminth infection. In addition to cysticerci of
Taenia solium and Taenia hydatigena found outside the gut, nine other helminth species
were found in guts: Echinostoma malayanum, Pseudanoplocephala crawfordi, Ascarops
dentata, Physocephalus sexalatus, Gnathostoma doloresi, Ascaris suum, Globocephalus sp.,
Oesophagostomum dentatum and Bourgelatia diducta. The study presents a report for the
first time of adult tapeworm, P. crawfordi infection in pigs from Thailand. For medical
importance, E. malayanum, P. crawfordi, G. doloresi and A. suum have been confirmed as
potentially zoonotic helminths and pigs may act as one of the reservoir hosts for human
helminthiases. Pigs of both gender and all ages appeared to be exposed to the parasites
equally and did not show any significant difference to these helminth species in richness and
total intensity.
MeSH terms: Animals; Myanmar; Cysticercosis; Cysticercus; Echinostoma; Gnathostoma; Helminthiasis; Helminths; Humans; Oesophagostomum; Parasites; Surveys and Questionnaires; Swine; Thailand; Ascaris suum; Sus scrofa; Taenia solium; Population Groups
A case of adult filarial worms detected in an
axillary lymph node of an asymptomatic
patient. A 64 year-old Indian female
underwent a mammogram and was
incidentally found to have punctate
microcalcifications in the upper outer
quadrant of the left breast with left axillary
lymphadenopathy. She has underlying
hypertension and diabetes mellitus on oral
medications. She has no family history of
breast malignancy. Fine needle aspiration of
the left axillary lymph node was suggestive
of reactive lympha-denitis. Histopathological
examination of excisional biopsy of left
breast lump showed fibrocystic disease;
no evidence of malignancy was detected
whereas excisional biopsy of left axillary
lymph node showed reactive lymphoid
hyperplasia, featuring variably sized
lymphoid follicles with intact mantle zone.
No expansion of marginal zone was noted.
Occasional pigment-laden macrophages
were seen. One of the lymph node showed
presence of calcified serpinginous tubular
bodies, in keeping with non viable parasite
organisms with intact outlines of the
structures. There were no eosinophilic
infiltrates. The possibility of filarial
infestation was suspected. Histopathological
sample was sent for further
identification and confirmed the presence
of adult filarial worm. (Copied from article).