Ponnamperuma T.,Ruhuna University |
Nicolson N.A.,Maastricht University
Journal of Abnormal Child Psychology | Year: 2016
The cognitive model posits that negative appraisals play an important role in posttraumatic stress disorder, in children as well as in adults. This study examined correlates of negative appraisals in relation to trauma exposure and their relationship to posttraumatic stress symptoms (PTSS) in 414 Sri Lankan adolescents, aged 12 to 16, living in areas impacted in varying degrees by the 2004 tsunami. In 2008, participants completed measures of negative appraisals, lifetime traumatic events, posttraumatic stress symptoms, internalizing symptoms, ongoing adversity, and social support. The majority (70 %) of the participants reported multiple traumatic events; 25 % met DSM-IV criteria for full or partial PTSD. Adolescents who had experienced more severe events, abusive events, greater cumulative trauma, or greater current adversity reported more negative appraisals. In regression analyses controlling for known risk factors such as female gender, cumulative trauma, ongoing adversity, and low social support, negative appraisals were the best predictor of PTSS, explaining 22 % of the variance. This relationship appeared specific to PTSS, as negative appraisals did not predict internalizing symptoms. Findings confirm the link between negative cognitions concerning traumatic events and persistent PTSS in adolescents, but longitudinal studies are needed to determine whether appraisals contribute to symptom maintenance over time. © 2015, The Author(s).
Goonewardene M.,Ruhuna University |
Shehata M.,University of Medical Sciences and Technology |
Hamad A.,James Cook University
Best Practice and Research: Clinical Obstetrics and Gynaecology | Year: 2012
Anaemia in pregnancy, defined as a haemoglobin concentration (Hb) < 110 g/L, affects more than 56 million women globally, two thirds of them being from Asia. Multiple factors lead to anaemia in pregnancy, nutritional iron deficiency anaemia (IDA) being the commonest. Underlying inflammatory conditions, physiological haemodilution and several factors affecting Hb and iron status in pregnancy lead to difficulties in establishing a definitive diagnosis. IDA is associated with increased maternal and perinatal morbidity and mortality, and long-term adverse effects in the new born. Strategies to prevent anaemia in pregnancy and its adverse effects include treatment of underlying conditions, iron and folate supplementation given weekly for all menstruating women including adolescents and daily for women during pregnancy and the post partum period, and delayed clamping of the umbilical cord at delivery. Oral iron is preferable to intravenous therapy for treatment of IDA. B12 and folate deficiencies in pregnancy are rare and may be due to inadequate dietary intake with the latter being more common. These vitamins play an important role in embryo genesis and hence any relative deficiencies may result in congenital abnormalities. Finding the underlying cause are crucial to the management of these deficiencies. Haemolytic anaemias rare also rare in pregnancy, but may have life-threatening complications if the diagnosis is not made in good time and acted upon appropriately. © 2011 Elsevier Ltd. All rights reserved.
Ilayperuma I.,Ruhuna University
International Journal of Morphology | Year: 2011
Cephalic index is an important parameter in evaluating racial and gender differences. A large body of evidence shows a clear racial variation in cephalic index. Therefore detailed knowledge of the population specific data on biometric features of the cranium is important in the study and comparison of the crania of populations from different racial backgrounds, assessing growth and development of an individual and in the diagnosis of any abnormalities of cranial size and shape. Despite its' significance, little is known concerning the cranial morphometry in Sri Lankans. Hence, the present study was undertaken to establish the cranial indices and head shapes in an adult Sri Lankan population. A total of 400 subjects with an age span of 20-23 years were included in the study. The cranial length, breadth and auricular head height of the subjects were recorded using a digital sliding caliper and Todd's head spanner. The horizontal, vertical and transverse cephalic indices were calculated using external dimensions of the skulls. There were significant gender differences in all principal cranial dimensions. The mean horizontal, vertical and transverse cephalic indices were 78.54, 78.68 and 100.52 respectively. The predominant cephalic phenotype of the study subjects were brachycephalic, hypsicephalic and acrocephalic. Among males dolicocephalics and among females brachycephalics dominated. The results of this study highlight the racial and gender differences in cranial morphometry and cephalic indices in an adult Sri Lankan population. The data will be of immense use in clinical, medico-legal, anthropological and archeological scenarios.
Hewage J.W.,Ruhuna University
European Physical Journal D | Year: 2014
Molecular dynamics simulation (MD) with Sutton-Chen potential for palladium-palladium, nickel-nickel and palladium-nickel interactions has been used to generate the minimum energy structures and to study the thermodynamic and dynamic properties of mixed transition metal cluster motifs of Ni n Pd(13-n) for n ≤ 13. Thirteen particle icosahedral clusters of neat palladium and nickel atoms were first reproduced accordingly with the results in literature. Then in the palladium icosahedra, each palladium atom has been successively replaced by nickel atom. Calculation is repeated for both palladium-centered and nickel-centered clusters. It is found that the nickel-centered clusters are more stable than the palladium-centered clusters and cohesive energy increases along the palladium end to nickel end. Phase transition of each cluster from one end-species to the other end-species is studied by means of caloric curve, root mean square bond fluctuation and heat capacity. Trend in variation of melting temperature is opposite to the energy trend. Palladium-centered cluster shows a premelting at low temperature due to the solid-solid structural transition. Species-centric order parameters developed by Hewage and Amar is used to understand the dynamic behavior in the solid-solid transition of palladium-centered cluster to more stable nickel-centered cluster (premelting). This species-centric order parameter calculation further confirmed the stability of nickel-centered species over those of palladium-centered species and solid-solid structural transition at low temperature. © 2014 EDP Sciences, SIF, Springer-Verlag Berlin Heidelberg.
Leelamanie D.A.L.,Ruhuna University
Catena | Year: 2016
The occurrence of water repellency in Sri Lankan soils has not been extensively studied and reported so far. Although most Sri Lankan soils are readily wettable, some soils show water repellent conditions. In this study, we examined a dune sand under Casuarina equisetifolia shelterbelt in Sri Lanka. The objectives were to ascertain the occurrence and the distribution of water repellency along the particle size fractions and to perceive the role of intermixed organic material in producing water repellency. The soil type is locally known to be sandy Regosols (USDA classification: Ustic Quartzipsamments). Bulk soil samples were taken from 0-5, 5-10, and 10-15 cm depths. Soil samples were separated into six size fractions by passing through a set of sieves and further separated into two sets as washed (with water) and untreated. Soil organic matter (SOM) content and the water repellency were discretely determined in untreated and washed samples. Water drop penetration time (WDPT) test and modified sessile drop method were used to estimate the water repellency. Despite the low SOM content (< 2%), water repellency was extreme (contact angle > 118°, WDPT > 3600 s) on the topmost layer (0-5 cm) and decreased with increasing soil depth. All the size fractions of the topmost layer showed significantly high repellency compared with those of the other two layers. Both the water repellency and the SOM content showed the highest values in the finest fraction and the lowest in the coarsest fraction. Washing samples with water decreased the WDPT in >. 96% of all size fractions in the 0-5 cm layer, and by lower proportions in the lower layers. Washing samples significantly decreased the contact angle of most size fractions although the decline did not exceed 15%. Washing with water removed a considerable portion of organic material. Despite the obvious declining through washing, both the SOM content and the water repellency showed the highest values in the smallest particle size fraction. Water repellency in both washed and untreated samples showed a considerably strong positive linear correlation with the SOM content suggesting that water-insoluble hydrophobic organic coatings might not be the dominant factor triggering water repellency in the tested sandy soils. © 2016 Elsevier B.V.
Jayasinghe S.S.,Ruhuna University
Journal of Postgraduate Medicine | Year: 2012
Background : Chronic damage to the central nervous system resulting in cognitive impairment has been shown with repeated, low doses of organophosphorus (OP) exposure over month or years. Aim: The study aimed to find out whether there is any cognitive impairment following acute OP exposure that could be detected by a simple screening instrument, the Mini Mental State Examination (MMSE), in clinical settings. Settings and Design: A cohort study. Materials and Methods: The study was conducted with matched controls. Consecutive patients admitted to the hospital with acute ingestion of OP were recruited. Cognitive function was assessed with the MMSE, digit span test, test of long-term memory function and concentration. Patients were assessed twice: at 1 and 6 weeks of exposure. Statistical Analysis: Continuous variables were analyzed with the paired and unpaired T-tests. Non-normally distributed data were analyzed with the Mann-Whitney U test and Wilcoxon Signed Rank test. Discrete variables were analyzed with the Chi-square test. Results: There were 60 patients and 61 controls. The mean age (SD) of the patients and controls was 31.5 (11.6) and 31.3 (11.8) years, respectively. Forty-two patients turned up for the second assessment. Significant impairment of cognitive function was seen in the total score of MMSE (95% CI-2.5 to-0.3), orientation (95% CI-1 to-0.2) and language (95% CI-0.9 to-0.1) domains of MMSE, digit span test (95% CI 0.1-1.7) and test of long-term memory function (95% CI 0.3-2.3) in the first assessment compared with the controls. When the results of the second assessment were compared with the controls, no significant differences were seen. Conclusion: Although there was a slight transient cognitive impairment detected with the screening tests following acute OP ingestion, no long-term cognitive defects was detected.
Sathiparan N.,Ruhuna University
Earthquake and Structures | Year: 2016
The structural collapse of masonry structure under dynamic loading displays many possible failure mechanisms often related to interaction between structural components. Roof collapse is one of the major damage mechanisms observed in masonry structures during an earthquake. Better connection between the roof diaphragm and walls may be preventing roof collapse, but it can affect other failure mechanisms. In spite of this fact, less attention has been paid to the influence of the roof diaphragm effect on masonry structures and little research has been implemented in this field. In the present study, the roof diaphragm effect on the unreinforced masonry structure under dynamic loading has been experimentally investigated. Three one-quarter scale one-story adobe masonry house models with different roof conditions have been tested by subjecting them to sinusoid loading on a shaking table simulator. Phenomena such as failure pattern, dynamic performance of masonry structure were examined. © 2016 Techno-Press, Ltd.
Ilayperuma I.,Ruhuna University
International Journal of Morphology | Year: 2010
Dimensional relationship between body segments and stature has been the focus of scientists for many years. All such studies were based on the fact that body segments exhibit consistent ratios relative to the stature and these ratios are linked to age, gender and race. Racial characters are best defined in the skull. Therefore, prediction of stature from cranial remains is vital in establishing the identity of an unknown individual. Despite its significance, little is known concerning the cranial dimensions in Sri Lankans. Hence, this study was designed to investigate the relationship and to propose a gender and age specific linear regression model between the cranial dimensions and height of an individual. A total of 400 subjects with an age span of 20-23 years were included in the study. The cranial length, breadth and auricular head height of the subjects were recorded using a digital sliding caliper and Todd's head spanner capable of measuring to the nearest 0.01mm. The height of the individual was measured standing erect, in anatomical position using a standing height measuring instrument. The findings indicated significant gender differences in all the mean cranial dimensions. Positive correlations between all cranial dimensions and stature were observed. Linear regression models for the prediction of stature from the above dimensions were formulated for both sexes. Cranial dimensions provide an accurate and reliable means in estimating the height of an individual. The regression formulae derived in this study will be of potential use in clinical, medico-legal, anthropological and archeological studies.
Hewage J.W.,Ruhuna University
Materials Chemistry and Physics | Year: 2016
Core/shell formation and surface segregation of multi shell icosahedral bimetallic silver-palladium nanostructures with the size of 55 and 147 atoms were studied by using the Molecular Dynamics simulations, and calculating Helmholtz free energy changes in the penetration of palladium atoms from shell to core, core to shell transition of silver and melting temperatures by using statistical mechanical densities of states. In 55 atoms icosahedra, two core-shell motifs, Ag13Pd42 and Pd13Ag42 with their isomers Pd13(Pd29Ag13) and Ag13(Ag29Pd13) were considered. Similarly in 147 atoms icosahedra, all mutations corresponding to the occupations of either silver atoms or palladium atoms in the core, inner shell or outer shell and their isomers generated by interchanging thirteen core atoms with thirteen atoms of the other type in the inner and outer shells were considered. It is found that the palladium-core clusters are more stable than the silver-core clusters and cohesive energy increases with the palladium composition. Phase transition of each cluster was studied by means of constant volume heat capacity. The trend in variation of melting temperature is accordance with the energy trend. Helmholtz free energy changes in palladium penetration, core to shell transition of silver and in surface mixing and segregation revealed the thermodynamic stability of the formation of PdcoreAgshell structures especially at silver rich environment and the surface segregation of silver. © 2016 Elsevier B.V.
Leelamanie D.A.L.,Ruhuna University |
Karube J.,Ibaraki University
Soil Science Society of America Journal | Year: 2014
It has long been established that heating, whether in situ or in the laboratory, can influence the hydrophobicity of soils. The objective of this study was to examine the surface hydrophobicity of Japanese Andisol and its behavior upon exposure to heat, considering the effect of heat at different levels of hydrophobicities, using natural and hydrophobized [with stearic acid (SA)] arable surface soil. For this purpose, samples were provided with two conditions: (i) kept at 25°C and 75% relative humidity, and (ii) exposed to 50°C for 5 h d-1 over a period of 40 d and the remaining time at 25°C and 75% relative humidity. Hydrophobicity was determined using contact angle and water drop penetration time (WDPT) measurements. Unhydrophobized samples exposed to 50°C showed 15% increment in contact angles and significant increment in WDPTs compared with those exposed to 25°C. In contrast, samples with 5 g kg-1 SA exposed to 50°C showed a 3.5% decrease in contact angles and substantial decrease in WDPTs compared with those kept at 25°C. The WDPT of these samples (5 g kg-1 SA) decreased from >3600 s at 25°C to values as low as about 2 s at 50°C, irrespective of the high contact angle (>100° at both 25 and 50°C). This was attributed to the formation of hydrophilic salts of SA due to heat and to the specific physical characteristics of Japanese Andisols, especially to the high porosity. © Soil Science Society of America.