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Search Results: 1 - 10 of 36 matches for " Susilakanthi Nanayakkara "
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Twelve Years of Rabies Surveillance in Sri Lanka, 1999–2010
Dushantha Karunanayake,Takashi Matsumoto,Omala Wimalaratne,Susilakanthi Nanayakkara,Devika Perera,Akira Nishizono,Kamruddin Ahmed
PLOS Neglected Tropical Diseases , 2014, DOI: 10.1371/journal.pntd.0003205
Abstract: Background Rabies is endemic in Sri Lanka, but little is known about the temporal and spatial trends of rabies in this country. Knowing these trends may provide insight into past control efforts and serve as the basis for future control measures. In this study, we analyzed distribution of rabies in humans and animals over a period of 12 years in Sri Lanka. Methods Accumulated data from 1999 through 2010 compiled by the Department of Rabies Diagnosis and Research, Medical Research Institute (MRI), Colombo, were used in this study. Results The yearly mean percentage of rabies-positive sample was 62.4% (47.6–75.9%). Three-fourths of the rabies-positive samples were from the Colombo, Gampaha, and Kalutara districts in Western province, followed by Galle in Southern province. A high percentage of the rabies samples were from dogs (85.2%), followed by cats (7.9%), humans (3.8%), wild animals (2.0%), and livestock (1.1%). Among wild animals, mongooses were the main victims followed by civets. The number of suspect human rabies cases decreased gradually in Sri Lanka, although the number of human samples submitted for laboratory confirmation increased. Conclusions The number of rabid dogs has remained relatively unchanged, but the number of suspect human rabies is decreasing gradually in Sri Lanka. These findings indicate successful use of postexposure prophylaxis (PEP) by animal bite victims and increased rabies awareness. PEP is free of charge and is supplied through government hospitals by the Ministry of Health, Sri Lanka. Our survey shows that most positive samples were received from Western and Southern provinces, possibly because of the ease of transporting samples to the laboratory. Submissions of wild animal and livestock samples should be increased by creating more awareness among the public. Better rabies surveillance will require introduction of molecular methods for detection and the establishment of more regional rabies diagnostic laboratories.
Terminal Resolutions of Brauer Pairs
Basil Nanayakkara
Mathematics , 2011,
Abstract: A Brauer pair is a pair (X, {\alpha}) where X is a quasi-projective variety over an algebraically closed field and {\alpha} is an element in the 2-torsion part of the Brauer group of the function field of X. A Brauer pair (Y, {\alpha}) is a terminal pair if the Brauer discrepancy of (Y, {\alpha}) is positive. We show that given a Brauer pair (X, {\alpha}), there is a terminal pair (Y, {\alpha}) with a birational morphism Y -> X. In short, any Brauer pair admits a terminal resolution.
Explicit energy expansion for general odd degree polynomial potentials
Asiri Nanayakkara,Thilagarajah Mathanaranjan
Physics , 2014, DOI: 10.1088/0031-8949/88/05/055004
Abstract: In this paper we derive an almost explicit analytic formula for asymptotic eigenenergy expansion of arbitrary odd degree polynomial potentials of the form $V(x)=(ix)^{2N+1}+\beta _{1}x^{2N}+\beta _{2}x^{2N-1}+\cdot \cdot \cdot \cdot \cdot +\beta _{2N}x$ where $\beta _{k}^{\prime }$s are real or complex for $1\leq k\leq 2N$. The formula can be used to find semiclassical analytic expressions for eigenenergies up to any order very efficiently. Each term of the expansion is given explicitly as a multinomial of the parameters $\beta _{1},\beta _{2}....$ and $\beta _{2N}$ of the potential. Unlike in the even degree polynomial case, the highest order term in the potential is pure imaginary and hence the system is non-Hermitian. Therefore all the integrations have been carried out along a contour enclosing two complex turning points which lies within a wedge in the complex plane. With the help of some examples we demonstrate the accuracy of the method for both real and complex eigenspectra.
Isospectral Hermitian counterpart of complex non Hermitian Hamiltonian $p^{2}-gx^{4}+a/x^{2}$
Asiri Nanayakkara,Thilagarajah Mathanaranjan
Physics , 2014, DOI: 10.1139/cjp-2012-0562
Abstract: In this paper we show that the non-Hermitian Hamiltonians $H=p^{2}-gx^{4}+a/x^2$ and the conventional Hermitian Hamiltonians $h=p^2+4gx^{4}+bx$ ($a,b\in \mathbb{R}$) are isospectral if $a=(b^2-4g\hbar^2)/16g$ and $a\geq -\hbar^2/4$. This new class includes the equivalent non-Hermitian - Hermitian Hamiltonian pair, $p^{2}-gx^{4}$ and $p^{2}+4gx^{4}-2\hbar \sqrt{g}x,$ found by Jones and Mateo six years ago as a special case. When $a=\left(b^{2}-4g\hbar ^{2}\right) /16g$ and $a<-\hbar^2/4,$ although $h$ and $H$ are still isospectral, $b$ is complex and $h$ is no longer the Hermitian counterpart of $H$.
Effects of complex parameters on classical trajectories of Hamiltonian systems
Asiri Nanayakkara,Thilagarajah Mathanaranjan
Physics , 2014, DOI: 10.1007/s12043-014-0750-5
Abstract: Anderson $\textit{et al}$ have shown that for complex energies, the classical trajectories of $\textit{real}$ quartic potentials are closed and periodic only on a discrete set of eigencurves. Moreover, recently it was revealed that, when time is complex $t$ $(t=t_{r}e^{i\theta _{\tau }}),$ certain real hermitian systems possess close periodic trajectories only for a discrete set of values of $\theta _{\tau }$. On the other hand it is generally true that even for real energies, classical trajectories of non $\mathcal{PT}$- symmetric Hamiltonians with complex parameters are mostly non-periodic and open. In this paper we show that for given real energy, the classical trajectories of $\textit{complex}$ quartic Hamiltonians $H=p^{2}+ax^{4}+bx^{k}$, (where $a$ is real, $b$ is complex and $k=1$ $or$ $2$) are closed and periodic only for a discrete set of parameter curves in the complex $b$-plane. It was further found that given complex parameter $b$, the classical trajectories are periodic for a discrete set of real energies (i.e. classical energy get discretized or quantized by imposing the condition that trajectories are periodic and closed). Moreover, we show that for real and positive energies (continuous), the classical trajectories of $\textit{complex}$ Hamiltonian $H=p^{2}+\mu x^{4}, (\mu=\mu _{r}e^{i\theta })$ are periodic when $\theta =4 tan^{-1}[(n/(2m+n))]$ for $\forall $ $ n$ and $m\in \mathbb{Z}$.
Sexual Dimorphism and Tooth Size Variation in the Permanent Dentition of the Uva Bintenna Veddas of Sri Lanka  [PDF]
Thushari Hewapathirana, Roshan Peiris, Deepthi Nanayakkara, Malkanthi Chandrasekara, Eugine Wikramanayake
Advances in Anthropology (AA) , 2014, DOI: 10.4236/aa.2014.41001
Abstract:

Forty-eight dental casts (37 males, 11 females) of Uva Bintenna Veddas were the population. Mesiodistal (MD) and buccolingual (BL) diameters were measured and analyzed for sexual dimorphism and size variation. In males, MD of maxillary canines and mandibular first molars were significantly greater at p < 0.01 and maxillary first molars and mandibular second molars at p < 0.05. Crown area was significantly greater at p < 0.01 for maxillary and mandibular first molars. Crown module was significantly greater at p < 0.01 for mandibular first molars and at p < 0.05 for maxillary first premolars, first molars and mandibular second molars. Maxillary canines, maxillary first molars and mandibular canines were the most sex ually dimorphic. First tooth of each tooth class I1, P1, and M1 showed least variability in both arches and in both sexes. In males, both MD and BL showed high variability in maxillary lateral incisors and mandibular second premolars.

A Model for the Estimation of Personal Stature from the Length of Forearm
Ilayperuma,Isurani; Nanayakkara,Ganananda; Palahepitiya,Nadeeka;
International Journal of Morphology , 2010, DOI: 10.4067/S0717-95022010000400015
Abstract: prediction of stature from incomplete and decomposing skeletal remains is vital in establishing the identity of an unknown individual. it has been stated that a variety of factors such as race, gender and nutrition play an important role in determining the height of an individual. estimation of stature from measurements of various long bones has been achieved with varying degree of accuracy. those studies resulted in establishing different formulae for the estimation of stature for the respective populations. however, evidence shows that there is a great void in such norms for sri lankans. hence, this study was designed to investigate the relationship and to propose a gender and age specific linear regression models between the ulna length and height of an individual. a total of 258 subjects with an age span of 20-23 years were included in the study. the ulna length was measured using a digital sliding caliper capable of measuring to the nearest 0.01 mm. the height of the individual was measured standing erect, in anatomical position using a standing height measuring instrument. the findings of the study indicated significant differences of the ulna length between the genders. a positive correlation between height and ulna length was observed in both sexes and it was statistically significant. regression equations for stature estimation were formulated using the ulna lengths for both males and females. the ulna length provides an accurate and reliable means in estimating the height of an individual. the regression formulae proposed in this study will be useful for clinicians, anatomists, archeologists, anthropologists and forensic scientists when such evidence provides the investigator the only opportunity to gauge that aspect of an individual's physical description.
Morphometric Analysis of the Mental Foramen in Adult Sri Lankan Mandibles
Ilayperuma,Isurani; Nanayakkara,Ganananda; Palahepitiya,Nadeeka;
International Journal of Morphology , 2009, DOI: 10.4067/S0717-95022009000400010
Abstract: evidence shows a clear racial variation in the position of the mental foramen. therefore, detailed knowledge of the morphometry of the mental foramen in different populations is essential in clinical dentistry when administering regional anesthesia, and performing peripheral surgery in the mental region of the mandible. the goal of this study was to elucidate the morphological features and precise anatomical position of the mental foramen with reference to surrounding anatomical landmarks in an adult sri lankan population. a total of fifty one adult dry mandibles were assessed to determine the number, shape, orientation, vertical and transverse diameters of the mental foramen and the distance between the mental foramen and symphysis menti. the position of the mental foramen was determined in relation to the mandibular teeth. data were evaluated between gender and side. the findings indicated that the most common position for the mental foramen was in line with the longitudinal axis of the lower second premolar (52.94%) followed by a position between first and second premolar (26.47%). the mean transverse and vertical diameters of the foramen were 3.31 ± 0.76 and 2.50 ± 0.61 mm, respectively. the mental foramen was located 24.87 ± 6.07 mm (right side) and 24.77 ± 6.07mm (left side) lateral to the symphysis menti. in the majority of cases, the mental foramen was oval in shape (59%) and its usual direction of opening was in a postero-superior direction (49.01%). the incidence of multiple mental foramina was 3.92%. the results of this study provide valuable information that will facilitate effective localization of the neurovascular bundle passing through the mental foramen thus avoiding complications from local anesthetic, surgical and other invasive procedures.
Morphometric Analysis of the Infraorbital Foramen in Adult Sri Lankan Skulls
Ilayperuma,Isurani; Nanayakkara,Ganananda; Palahepitiya,Nadeeka;
International Journal of Morphology , 2010, DOI: 10.4067/S0717-95022010000300019
Abstract: evidence supports a clear racial variation in the position of the infraorbital foramen. therefore detailed knowledge of the population specific data on biometric features of the infraorbital foramen will facilitate therapeutic, diagnostic and surgical manipulations in the maxillo-facial region. the goal of this study was to elucidate the morphological features and precise anatomical position of the infraorbital foramen with reference to surrounding anatomical landmarks in an adult sri lankan population. a total of one hundred and eight adult dry skulls were assessed to determine the number, shape, orientation, vertical and transverse diameters of the infraorbital foramen, transverse distance from the infraorbital foramen to the maxillary midline and the zygomatico-maxillary suture and the vertical distance from the infraorbital foramen to the infraorbital rim and supraorbital foramen. the position of the infraorbital foramen was determined in relation to the maxillary teeth and the supraorbital foramen.the findings indicated that the size of the infraorbital foramen and the mean distances from the infraorbital foramen to the maxillary midline, infraorbital rim and supraorbital foramen was significantly larger in males than in females. the modal position for the infraorbital foramen was in line with the long axis of the second upper premolar and the supraorbital and infraorbital foramina were lying in the same sagittal plane only in 24.07 % of the skulls. the results highlight the racial and gender differences of the infra orbital foramen and emphasize the need for meticulous preoperative evaluation of the infraorbital foramen in patients who are candidates for maxillo-facial surgeries and regional block anesthesia.
Incidence of Humeral Head of Biceps Brachii Muscle: Anatomical Insight
Ilayperuma,Isurani; Nanayakkara,Ganananda; Palahepitiya,Nadeeka;
International Journal of Morphology , 2011, DOI: 10.4067/S0717-95022011000100037
Abstract: biceps brachii is stated as one of the muscles that shows most frequent anatomical variations. its most commonly reported anomaly is the presence of an accessory fascicle arising from the humerus which is termed as the humeral head of biceps brachii. evidence shows a clear racial trend in the incidence of the humeral head of biceps brachii. therefore, detailed knowledge of this variation in different populations is important for surgical interventions of the arm, nerve compression syndromes and in unexplained pain syndromes in the arm or shoulder region. the goal of this study was to elucidate the incidence and morphological features of this muscle in an adult sri lankan population. upper extremities of the total of one hundred thirty five cadavers were dissected and studied for the presence of accessory heads of the biceps brachii muscle. the proximal and distal attachments of the humeral heads as well as their cranio-caudal, antero-posterior and medio-lateral dimensions were recorded. the incidence of humeral head of biceps brachii was found to be 3.7%. in all cases, it was found unilaterally and only in male subjects. the humeral head originated from the antero-medial aspect of the humeral shaft and descended and merged with the other two heads to form a common tendon. the results of the present study further highlight the racial variations in the incidence of humeral head of biceps brachii among sri lankans. knowledge of the occurrence of humeral head of biceps brachii may facilitate preoperative diagnosis as well as the surgical procedures of the upper limb thus avoiding iatrogenic injuries.
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