89 research outputs found
Aspidura desilvai Mendis Wickramasinghe & Bandara & Vidanapathirana & Wickramasinghe 2019, sp. nov.
No full textAspidura desilvai sp. nov. (Figures 1–7) Holotype. NMSL-NH 2019.01.0 2, adult male, 168 mm SVL (Figure 2), from Riverstone, Knuckles, Matale District, Central Province, Sri Lanka (07°31’39” N, 80°44’01” E, elevation 1420 m). Collected by L.J.M. W and D.R.V. on 0 7 July 2018. Paratypes. NMSL-NH 2019.01.0 1, adult female, 208 mm SVL, from Panwila in Knuckles Mountain Range, Kandy District, Central Province in Sri Lanka (07°22'00.36’’ N, 080°41'00.10’’ E, elevation 995 m). Collected by L.J.M. W and I.N.B. on 13 March 2011; DWC 2019.05.0 1, adult female, 157 mm SVL, from Dotulugala, Knuckles Mountain Range, Kandy District, Central Province, Sri Lanka (07°27'00.30” N, 080°45'00.20” E, elevation 1700 m). Collected by L.J.M. W and I.N.B. on 17 March 2011; DWC 2019.05.0 2, juvenile male, 93 mm SVL, from Gombaniya Mountain, Knuckles Mountain Range, Matale District, Central Province, Sri Lanka (07°27'51.76’’ N, 080°45'51.79’’ E, elevation 1375 m). Collected by L.J.M. W and I.N.B. on 13 March 2011. Diagnosis. SVL 94–216 mm; snout to eye distance 2.5 times the eye width (SE/EW); prefrontals touching eye; preocular small, does not touch supraocular; postoculars 2, lower one larger than the upper; temporal 1+2/1+2; supralabials 6/6, 4 th touching eye; infralabials 6/6, first pair in contact, progressively increasing in size from 1 st to 6 th; anterior chin shields 2, large, touching 1–4 infralabials; posterior chin shields 2, anterior half in contact while the posterior half separated by 1 st ventral; ventrals 124–139; subcaudals 16–29; dorsal scale rows 15–15–15; laterally spine like tubercles present on two scale rows nearest to the subcaudals of the ischiadic, anal and tail base regions in adult males, feeble in juvenile males, and absent in females; entire dorsum brown colour, much paler towards anterior; three irregular dotted lines on dorsum. Description of holotype. Adult male; SVL 168 mm; TaL 25.1 mm; TL 193.1 mm; TaL/TL 0.13; body elongate and cylindrical; head short (SVL/HL 18.3), elliptical, indistinct from thick neck; snout long, narrowing anteriorly, pointed in dorsal aspect, snout to nostril distance about 2.8 (EW/SN) times as long as nostril width; nasal divided; small, triangular nostril, touching divided nasal and first supralabial, not touching rostral; eye larger than horizontal diameter of nostril, distance between snout to eye about 2.6 (SE/EW) times the eye width, round pupil; snout to eye distance 0.3 times head length (SE/HL); tail short (TaL/SVL 0.1), robust at its base, tapering progressively to a single point. Head scalation. Head scalation includes 1 internasal, 2 prefrontals, 2 supraoculars, 1 frontal, and 2 parietals (Figure 3A). Rostral small, convex, wider than long and rounded in lateral, dorsal and ventral aspects. Nasal vertically divided by a groove above nostril (Figure 3B). Internasal large, irregular hexagonal; widely in contact with prefrontals. Two large prefrontals, longer and wider than internasals, largest distance along the longitudinal axis of prefrontals shorter than frontal (Figure 3A) in length, anterior-most corner of prefrontals touching nasal, bordered by 2 nd and 3 rd supralabial, preocular scale, eye, supraocular and frontal. Preocular small, not in contact with supraocular. Loreal and subocular scales absent. Supraocular smaller than frontal. Two postoculars, lower one larger than upper. Two parietals; largest scales on head. Temporals 1+2/1+2. Supralabials 6/6, 4 th touching eye, progressively increasing in size from 1 st to 6 th (Figure 3B). Mental small and triangular, wider than long. Infralabials 6/6, first pair in contact, progressively increasing in size from 1 st to 6 th. Anterior chin shields 2, large, touching 1–4 infralabials. Posterior chin shields 2, anterior half in contact, posterior portion separated by 1 st ventral (Figure 3C). Body scalation. Ventrals 124, 1 st ventral longer than wide; subcaudals 24, all single; anal single and large; dorsal scale rows 15–15–15; laterally prominent spine like tubercles present on two scale rows nearest to the subcaudals, and its protrusion reducing towards upper scale rows in the ischiadic, anal and tail base regions (Figure 4); vertebral rows and first coastal not enlarged; no apical pit. Hemipenis morphology. Based on Holotype specimen: right everted hemipenis extends for length of 3 subcaudals. Everted organ single subcylindrical, globular, sulcus spermaticus simple. Basal to apex region bearing prominent spines which are evenly distributed and are in uniform length (Figure 5). Colour in life. Supralabials and infralabials light yellow, with dark margins separating each scale (Figure 6A). Entire dorsum reddish brown colour, much paler towards anterior and each scale having tiny dark spots (Figure 2). Three irregular dotted lines on dorsum (Figure 6B). These are symmetrically placed and continues from neck to tail end. Prominent light brown stripe continues dorsolaterally from neck to tail end, marked due to much darker regions which constitutes of dotted lines below and above this region. These lines continue from neck to tail end. Venter primarily peach, with black blotching all over; gular region yellow. Colour in alcohol. Colour pattern remains unchanged. Pupil changes to off white. Darker regions fades to a light brown. Variations in colour. In an unpreserved male specimen (Figure 7D) except the head region and ventre the entire body was black. Natural History. Aspidura desilvai sp. nov. have been observed commonly in its habitat (Figure 1). The species is confined to Knuckles conservation area, and is found in and above the lower montane forests of Knuckles. Authors have observed the snake from 995 m up to 1700 m above sea level (Figure 8). The habitat of A. desilvai sp. nov. is closed canopy forests dominated by Syzigium sp. (Figure 9). The moist-cooler habitat is densely occupied with large and medium sized trees which are heavily covered with epiphytes. No direct sunlight falls to the forest floor, and the undergrowth was not well established where the individuals were found. Relatively thin litter cover was observed in the habitat. Commonly observed under leaf litter and loose soil while they were also observed under rocks, boulders, and decaying logs. Individuals come out to the surface during the day time. Reddish brown latosolic soil in the locality is more or less similar to the body colour of the snake. Etymology. The species is named in honor of Pilippu Hewa Don Hemasiri de Silva (Dr. P. H. D. H. de Silva), a former Director (1965-1981) of the National Museums of Sri Lanka. In recognition of his tireless services to the country, while in service and through his many publications specially as the author of the book titled “ Snake Fauna of Sri Lanka, with special reference to skull, dentition and venom in snakes ”. The species epithet desilvai is a noun in the genitive case. Suggested common names. desilvage madilla, and de Silva’s Rough-Side Snake in native Sinhala language and English language respectively. Comparison. The new species was compared with all known congeners of the genus Aspidura and the species most closely resembles A. ravanai, and A. trachyprocta, due to the following combination of characters: one preocular, two postoculars, 1+2 temporals, supralabials 6, 4 th supralabial in contact with the eye, infralabials 6, coastals 15, single cloacal scale, and overlapping ventral and subcaudal counts, but can easily be distinguished by the following morphological characters: from A. ravanai: entire dorsum brown colour, much paler towards anterior and each scale having tiny dark spots in Aspidura desilvai sp. nov. (vs. entire dorsum jet black in Aspidura ravanai), ventrolaterally darker region which constitutes of irregular longitudinal dotted lines (vs. ventrolaterally an irregular longitudinal yellow stripe), laterally prominent spine like tubercles present on two scale rows nearest to the subcaudals, and its protrusion reducing towards upper scale rows (vs. entire coastal rows coarsely keeled, with 1–3 peaks on each scale) in males (Figures 4 & 10 A–C), entire coastal rows of the ischiadic, anal and tail base regions smooth (vs. feebly keeled) in females, snout to eye distance about 2.5 times its eye width (vs. 3.2 times in A. ravanai) (Figures 3 & 10 D–E); from Aspidura trachyprocta: entire dorsum brown colour, much paler towards anterior and each scale having tiny dark spots in A. desilvai sp. nov. (vs. reddish-yellow to brown with a longitudinal black stripe on mid dorsum in Aspidura trachyprocta), ventrolaterally darker region which constitutes of irregular longitudinal dotted lines (vs. black stripe), laterally prominent spine like tubercles present on two scale rows nearest to the subcaudals, and its protrusion reducing towards upper scale rows (vs. bulging spine like tubercles prominent laterally which reduces towards dorsum) of the ischiadic, anal and tail base regions in males (Figures 4 & 11 A–C), entire coastal rows of the ischiadic, anal and tail base regions smooth (vs. feebly keeled) in females, snout to eye distance about 2.5 times its eye width (vs. twice in A. trachyprocta) (Figures 3 & 11 D–E); from A. brachyorrhos Boie, 1827, by having 15 coastals (vs. 17), preocular not in contact with supraocular (vs. contact), prefrontal contact with eye (vs. separate), single subcaudals (vs. paired); from A. copei Günther, 1864 by having coastals 15 (vs. 17), single subcaudals (vs. paired), single preocular (vs. absent); from A. deraniyagalae Gans & Fetcho, 1982 by having 15 coastals (vs. 17), ventrals 124–139 (vs. 117–122), single subcaudals (vs. paired); from A. drummondhayi Boulenger, 1904, by having single subcaudals (vs. paired), single preocular (vs. absent); from A. guentheri Ferguson, 1876 by having 15 coastals (vs. 17), ventrals 124–139 (vs. 100–127); from A. ceylonensis (Günther, 1858), by prefrontal touching eye (vs. not touching eye), preocular does not touch supraocular (vs. touches), lower postocular larger than the upper (vs. vise versa), mid body coastals not keeled (vs. coarsely keeled).Published as part of Mendis Wickramasinghe, L. J., Bandara, Imesh Nuwan, Vidanapathirana, Dulan Ranga & Wickramasinghe, Nethu, 2019, A new species of Aspidura Wagler, 1830 (Squamata: Colubridae: Natricinae) from Knuckles, World Heritage Site, Sri Lanka, pp. 265-280 in Zootaxa 4559 (2) on pages 266-272, DOI: 10.11646/zootaxa.4559.2.3, http://zenodo.org/record/262697
The search for our cosmic ancestry
No full textThe idea that life is a cosmic, rather than a purely terrestrial phenomenon, has progressed from scientific heresy to mainstream science within the short timespan of a few decades. The theory of cometary panspermia developed by Fred Hoyle and the present author in the 1970's has been vindicated by a spate of new discoveries in astronomy and biology, and also with startling new evidence of microbial fossils in meteorites and micrometeorites. The recent Kepler Telescope searches for exoplanets have indicated the presence of over 100 billion habitable planets separated by only a few light years, thus making panspermia and the transfer of microbial life between such planets an inevitable fact. The book presents a comprehensive and up-to-date account of the Hoyle-Wickramasinghe theory of cometary panspermia in a manner accessible to a wide general readership
WhatsApp Peer Coaching Lessons for eHealth
No full textWhatsApp was evaluated as a peer coach group support tool in a healthy lifestyle intervention with 15 young professionals. These individuals were time-constrained professionals, so two design challenges were to create enough attractiveness and quality in the peer group interactions. There were three main health domains: food, physical activity, and mental energy. As a result of the 12 week pilot, there were 127 WhatsApp peer coaching inputs. The variety of inputs was better than in a previous pilot; peer coaching quality improved; plus there was more continuity following the initial two weeks. Community building remained a challenge, especially in the longer run. Two design solutions seemed to work: pre-designed coach-inputs across health domains, plus the instructions for a health advocate from the group, per health domain. Based on the results, the authors hypothesize that user needs in the first five weeks …Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Interactive Intelligenc
Investigating the Crustal Structure near the Mahakandarawa seismic station in Sri Lanka through the Receiver Function Method
No full textSri Lanka has a very ancient geological history that begins in the Precambrian, when it formed part of the Gondwana supercontinent. It was connected to India, Madagascar, Antarctica, and Africa, sharing the same crustal evolution. When Gondwana began to break apart around 180 million years ago, Sri Lanka drifted with the Indian plate to reach its present position in the Indian Ocean. The present work analyzes the subsurface structure beneath the Mahakandarawa (MALK) broadband seismic station using teleseismic P-wave conversions. A combination of converted wave analysis and H-κ stacking was applied to determine both Moho depth and the velocity ratio of compressional to shear waves. The approach indicates a crustal thickness of nearly 37.8 km with a velocity ratio of 1.73, giving a Poisson’s ratio close to 0.25. Such values are typical of silica-rich, felsic material rather than mafic compositions. When compared with previous studies from neighboring Gondwanan fragments such as southern India and Madagascar, which report Moho depths of ~36–39 km and similar felsic crustal compositions, the results from MALK show strong consistency. This agreement reinforces Sri Lanka’s geological affinity with East Gondwana and provides new regional constraints on its tectonic evolution, particularly regarding the preservation of ancient felsic crust across separated continental blocks.Keywords: Teleseismic Receiver Function, Gondwana, Sri Lanka, Crustal Structure, H-κ stackin
Rhinophis roshanpererai Wickramasinghe, Vidanapathirana, Rajeev & Gower, 2017, sp. nov.
No full textRhinophis roshanpererai sp. nov. Figs. 1–5; Table 1 Holotype. NMSL 2016.08.0 1 NH (Figs. 2–3; Table 1), adult male, 207.9 mm SVL, Galkanda, Beragala, Badulla District, Uva Province, Sri Lanka (6° 45’ 07.98” N, 80° 57’ 20.23” E, elevation 940 m). Collected by L.J. Mendis Wickramasinghe, Dulan Ranga Vidanapathirana, and M. D. Gehan Rajeev, 10 May 2010. Paratypes. DWC 2016.05.0 3, adult female, 205.2 mm SVL (Fig. 4 A); DWC 2016.05.0 4, adult female, 218.2 mm SVL (Fig. 4 B–5). Collection data as for holotype. Diagnosis. A Rhinophis restricted to the Central Highlands of Sri Lanka with 17 dorsal scale rows at midbody, more than 160 and fewer than 175 ventral scales, a small tail shield with spines, three or four of which prominent, and lacking yellowish markings laterally or dorsally. Identification. The new uropeltid species is referred to Rhinophis because it has an eye that lies within an ocular scale (not so in Platyplectrurus Günther, 1868), has a clearly discrete tail shield, lacks a mental groove (present in Melanophidium Günther, 1864), lacks supra- or postoculars or temporals (at least one of which is present in Brachyophidium Wall, 1921, Platyplectrurus, Plectrurus Duméril, 1851, and Teretrurus Beddome, 1886), lacks midline contact between the nasals (present in Brachyophidium, Melanophidium, Platyplectrurus, Plectrurus, Pseudoplectrurus Boulenger, 1890, Teretrurus, and Uropeltis), and it has midbody dorsal scales in 17 rows (15 in Brachyophidium, Melanophidium, Platyplectrurus, Plectrurus, Pseudoplectrurus, Teretrurus). Rhinophis roshanpererai sp. nov. differs from all four Indian species of Rhinophis by having a very small tail shield with spines (versus relatively much larger tail shield without spines). It differs further in having a ventral count of 168 or 169 (versus more than 200 in R. goweri Aengals and Ganesh, 2013, fewer than 150 in R. travancoricus Boulenger, 1893, and more than 170 in R. fergusonianus Boulenger, 1896); and in having 17 midbody dorsal scale rows (versus 15 in R. sanguineus Beddome, 1863). Among Sri Lankan congeners, Rhinophis roshanpererai sp. nov. differs from R. saffragamus (Kelaart, 1853) in not having a large and flat tail shield or midline contact between the opposite nasal shields, and by having dorsal scales in 17 rather than 19 rows at midbody. The new species differs from R. dorsimaculatus Deraniyagala, 1941, R. homolepis (Hemprich, 1820), R. lineatus, R. oxyrynchus (Schneider, 1801), R. porrectus Wall, 1921, R. punctatus Müller, 1832 and R. zigzag by having fewer than 175 ventral scales (versus more than 180), and by having a very small tail shield with spines (versus relatively much larger tail shield without spines). Rhinophis roshanpererai sp. nov. differs from R. phillipsi (Nicholls, 1929) in having fewer than 190 ventrals and in lacking yellow lines on the dorsum. Rhinophis roshanpererai sp. nov. resembles R. melanogaster in having a small tail shield, but the new species has a shield surface with four (or three) notably prominent spines, one pair above the other (versus two slightly larger spines ventrally); absence of yellowish lines laterally (versus present); perhaps more ventral scales (168–169 versus 152–166); and a distinct geographical distribution (central highlands of Badulla District vs Knuckles Range, Matale and Kandy Districts). The ventral scale count in R. roshanpererai sp. nov. is similar to or overlapping with those for R. blythii Kelaart 1853, R. drummondhayi Wall, 1921, R. philippinus (Cuvier, 1829), and R. tricolorata Deraniyagala, 1975, but the new species differs from these four Sri Lankan congeners by having a smaller tail shield with spines, three or four of which are prominent (versus large tail shield without notable spines). The new species differs from R. erangaviraji by having more than 165 ventrals (versus fewer than 155), a smaller tail shield, and by lacking substantial yellow areas on the lateral surface of the body and tail. Description of holotype. See Table 1 for morphometric and meristic data. A preserved specimen in good condition; 20 mm long left of ventral incision into coelom extending anteriorly from 10 mm anterior to vent; outer layer of scales loose and missing in parts; a few flank scales more profoundly damaged on left at approximately midbody. Head small, snout pointed (Figs. 2–3). Rostral pointed, longer than wide, without dorsal crest; widest at level of anterior superior corner of first supralabials. Rostral several times longer (in dorsal view) than rostralfrontal gap (Fig. 3). Frontal irregularly hexagonal, longer than wide, lateral (ocular) margins slightly converging posteriorly, posterolateral margins straight to very slightly concave; lateral (ocular) margin shortest, posterolateral edges longest. Frontal longer, wider than rostral. A pair of nasals, separated from each other by posterior half of rostral. External naris small, subcircular, slightly countersunk within small depression, located in anteroventral corner of nasal. Nasal in contact with first and second supralabials. Prefrontals (for most of their length) in contact with each other along midline (left overlapping right), separating frontal from rostral. Prefrontals wider than long, shorter than frontal. Supralabials four, first smallest, making the least contribution to margin of mouth; fourth much the largest. Ocular in contact with third and fourth supralabials. Eye distinct, diameter approximately one third length of ocular, located near anteroventral corner of ocular, bulging slightly from ocular surface, pupil circular. Paired parietals longer than wide, shorter, very slightly wider than frontal, posteriorly broadly rounded, angle between postermedial and posterolateral edges approximately 90°. Opposite parietals in brief midline contact, left overlapping right. Each parietal contacts four scales other than head shields. No mental groove; mental wider than long, smaller than infralabials, contacting first infralabials and single postmental (= first ventral); three pairs of infralabials, second largest, first smallest. First and second ventrals longer than wide, third approximately as long as wide, fourth and subsequent ventrals wider than long. Six or seven maxillary and approximately seven mandibular teeth on each side. Teeth simple, pointed, distinctly retrorse, straight, evenly spaced. Body cylindrical. Body scales generally evenly sized on dorsum and along body except for those involved in dorsal scale row reductions. Midline ventral scales between mental and anal of even size though anteriormost ones gradually narrow. Ventrals 168, posteriormost ventral notably smaller, penultimate ventral paired. Dorsal scale rows 19 anteriorly, reducing to 17 by level with 30th ventral and maintained along most of body; scale row reduction formula: 3 + 4 (30) 19 --------------- 17 3 + 4 (30) Dorsal scale rows approximately 14 at base of tail. Head and body scales macroscopically smooth, lacking keels. Inconspicuous keels on scales on posteriormost portion of body and on tail, increasingly prominent posteriorly, more obvious ventrally (including on anals) and ventrolaterally. Paired anal scales (right overlying left) considerably larger than posteriormost ventrals and subcaudals. Distal margin of each anal overlaps three other scales in addition to anteriormost subcaudals. Seven right and seven left subcaudals. Tail 'shield' mildly conical, forming tip of tail, small, longer than wide in dorsal view, shorter than the frontal in dorsal view, visible from below and especially above, base (much narrower than base of tail) surrounded by last pair of subcaudals and 6 other scales. In posterior view shield oval to slightly egg-shaped, wider ventrally than dorsally (Fig. 3). Shield surface sparsely spinose, most spines small, inconspicuous but four (arranged in two pairs, one above the other) much longer and substantial, pointing straight backwards; ventral pair of larger spines notably longer than dorsal pair (Fig. 3). Colour in life. Dorsum and lateral background uniform black, with sparse, very small yellow flecks (Fig. 2). Ventral background dark brown for most of length, gradually paler anteriorly, darker posteriorly (similar to dark colour of dorsum). Anterior and underside of snout paler than rest of head. Venter with conspicuous yellow blotching, blotches notably larger than on dorsum and lateral surfaces of body; ventral blotching absent on tail, head and anteriormost and posteriormost of body. Colour in alcohol. Colour pattern remains with a little fading, black to dark brown, yellow to off white and brown to a paler brown (Fig. 3). Paratypes and variation. Paratype DWC 2016.05.0 3 is slightly longer (218.2 mm SVL) than the holotype and the other paratype (DWC 2016.05.04) slightly shorter (205.2 mm SVL), both are female. The two paratypes are very similar to the holotype with respect to the description presented above, including identical scale row reductions (19 to 17 rows by level of 30th ventral). DWC 2016.05.0 3 differs from the holotype in having: parietals more notably wider than frontal (Fig. 4 A); seven rather than six scales plus last pair of subcaudals surround base of tail shield; posteriormost ventral paired; supernumerary scale between second pair of subcaudals (Fig. 4 A). DWC 2016.05.0 4 differs from the holotype in having six rather than seven subcaudals on right side, and in having three rather than four major spines on the tail shield, two posteroventrally and one posterodorsally (Fig. 5). Both paratypes appear to have seven maxillary teeth on each side; mandibular counts are more difficult but are estimated at six or seven on each ramus. Paratypes closely resemble holotype in colour pattern. Etymology. The species epithet roshanpererai is named for the late Roshan Perera, who was an Instructor of the Reptiles group of the Young Zoologist’s Association of Sri Lanka, Department of National Zoological Gardens, in recognition of his dedicated services to wildlife conservation in Sri Lanka. The species name roshanpererai is a noun in the genitive case. Suggested vernacular names. Roshan Pererage thudulla, Roshan Pereravin nilakael pambu, Roshan Perera’s sheildtail (or Roshan Perera’s Rhinophis) in Sinhala, Tamil, and English, respectively. Distribution, habitat and threats. The first author first encountered the new species as a single roadkill specimen at the type locality in 1999. In five or six subsequent visits to the type locality approximately 30 individuals of Rhinophis roshanpererai sp. nov. have been observed, including a second roadkill specimen. The type series of R. roshanpererai sp. nov. was found within a 1 m radius, dug during the day from soil ca. 150 mm deep among banana plants in a home garden. Other specimens have been seen at or close to (within a couple of kilometers) of this site in a wide range of habitats, including shaded patches of grassland, tea plantations, and disturbed riverine forest, always dug from soil or leaf litter during the day. A few specimens have been seen moving on the surface, only at night. Several other individuals of the new species were dug from soil in disturbed riverine forest in 1999 from Uda Diyaluma, approximately 10 km away (6° 44’ 08.55” N, 81° 01’ 57.10” E, elevation 750 m), and from Haldummulla, approximately 6 km from the type locality (6° 45’ 39.95” N, 80° 54’ 05.73” E, elevation 938 m). Despite a substantial amount of fieldwork (including digging through soil and leaf litter) at similar altitudes, we have not observed this species outside this region, including at, for example, Haputale, less than 2 km North of the type locality but approximately 400 m higher in elevation. Rhinophis roshanpererai sp. nov. has not been found in sympatry with other uropeltid species. The nearest observation of other species that we know of (L.J.M.W., pers. obs.) is for R. drummondhayi at 960 m elevation at Kubalwela, approximately 16 km to the northeast by north (bearing of 30°) of the type locality of R. roshanpererai sp. nov.. We suspect that the vertical and horizontal distributional range of the new species is small, and that substantial human disturbance in the form of intensive agriculture and urbanization represent the likely greatest conservation threats.Published as part of Mendis Wickramasinghe, L. J., Vidanapathirana, Dulan Ranga, Gehan Rajeev, M. D. & Gower, David J., 2017, A new species of Rhinophis Hemprich, 1820 (Serpentes: Uropeltidae) from the central hills of Sri Lanka, pp. 153-164 in Zootaxa 4263 (1) on pages 155-161, DOI: 10.11646/zootaxa.4263.1.7, http://zenodo.org/record/57259
Conditional Complexity of Compression for Authorship Attribution
No full textWe introduce new stylometry tools based on the sliced conditional compression complexity of literary texts which are inspired by the nearly optimal application of the incomputable Kolmogorov conditional complexity (and presumably approximates it). Whereas other stylometry tools can occasionally be very close for different authors, our statistic is apparently strictly minimal for the true author, if the query and training texts are sufficiently large, compressor is sufficiently good and sampling bias is avoided (as in the poll samplings). We tune it and test its performance on attributing the Federalist papers (Madison vs. Hamilton). Our results confirm the previous attribution of Federalist papers by Mosteller and Wallace (1964) to Madison using the Naive Bayes classifier and the same attribution based on alternative classifiers such as SVM, and the second order Markov model of language. Then we apply our method for studying the attribution of the early poems from the Shakespeare Canon and the continuation of Marlowe’s poem ‘Hero and Leander’ ascribed to G. Chapman.compression complexity, authorship attribution.
Need for an Ecological Index
No full textThe article was published in the Sri Lankan newspaper 'The Island' on the 30th November 2005 after the World Environmental Education Congress (WEEC) held in Milan. Author hopes it could provide a base for a project for senior school children or more senior students to devise an Ecological Index and ‘If nothing else, it could help them in thinking out the issues involved!’ Author supposes that could be a form of environmental education
A detailed study of the reflection nebula, NGC 7023
No full textPolarisation and intensity maps in three broad wavebands are presented for the reflection nebula NGC7023. The data are used to investigate the structure, dust distribution and grain characteristics of the material surrounding the central illuminating star HD200775 of the reflection nebula. Calculations have been made, using a Monte-Carlo technique, for various parameters representing the structure and content of the nebula to predict and explain the observed measurements. The successful description of the observations puts severe restrictions on the nebular parameters. It is found that the geometry of the nebula is in the form of an extended cloud with a foreground conical cavity in which the illuminating star is situated. The dust grains are required to have a power law size distribution of the form n(a) = a(^4.05) and grain material corresponding to silicates is most likely although ice cannot be excluded
Cataclysmic variables from a ROSAT/2MASS selection. I, Four new intermediate polars
No full textWe report the first results from a new search for cataclysmic variables (CVs) using a combined X-ray (ROSAT)/infrared (2MASS) target selection that discriminates against background active galactic nuclei. Identification spectra were obtained at the Isaac Newton Telescope for a total of 174 targets, leading to the discovery of 12 new CVs. Initially devised to find short-period low-mass-transfer CVs, this selection scheme has been very successful in identifying new intermediate polars. Photometric and spectroscopic follow-up observations identify four of the new CVs as intermediate polars: 1RXS J063631.9+353537 P(orb)similar or equal to 201 min, P-spin= 1008.3408 s or 930.5829 s), 1RXS J070407.9+262501 (P(orb)similar or equal to 250 min, P-spin= 480.708 s) 1RXS J173021.5-055933 (P-orb= 925.27 min, P-spin= 128.0 s), and 1RXS J180340.0+401214 (P-orb= 160.21 min, P-spin= 1520.51 s). RX J1730, also a moderately bright hard X-ray source in the INTEGRAL/IBIS Galactic plane survey, resembles the enigmatic AE Aqr. It is likely that its white dwarf is not rotating at the spin equilibrium period, and the system may represent a short-lived phase in CV evolution
Security Engineering and Federated Learning for Healthcare Information Systems
No full textDigitalization revolutionizes healthcare by enabling seamless information access to stakeholders, enhancing service efficiency, personalizing care, and bolstering online health support. However, current health systems face challenges. Health information is often siloed in the existing systems, which makes data sharing difficult due to varying formats, export interfaces, and standards. Healthcare providers are also required to comply with data regulations like the EU General Data Protection Regulation (GDPR) to maintain patients’ data. Advancements in healthcare practices, such as telemedicine and precision medicine, alongside increased individual utilization of digital systems and limitations in data exchange, are leading the shift from traditional electronic health record (EHR) systems to patient-centered healthcare information systems (PHSs). PHS complements the EHRs, makes patients aware of their health, and offers new features like complete control of their medical data and provision of vetted information. PHSs are deployed on traditional technologies such as centralized databases, peer-to-peer (P2P), or distributed ledger technology (DLT). P2P PHSs include interoperable COVID-19 proximity trackers or decentralized personal health records. Utilizing P2P technology for PHS deployment situates data locally at the edge, under the sovereignty of individual device owners, increasing scalability and reducing the attack surface and organizational hurdles to implementing data regulations. However, health information on P2P networks raises distinct security challenges, which could affect the attainment of PHS goals. For example, the absence of reliable and trusted computing bases on P2P networks and the responsibility of users to support their devices’ information security independently pre-sent profound adverse security risks.
Moreover, in P2P PHS, data are in isolated, heterogeneous, and distributed environments. While this is favorable for certain security aspects, it brings challenges to traditional data transaction procedures in machine learning (ML). In addressing these issues, this dissertation focuses on the novel P2P PHS. It aims to: i) identify current design and architectural patterns for P2P PHS and P2P networks and propose a novel but secure architecture for PHS deployment; ii) systematically investigate the inherent and possible security issues for P2P PHS; iii) propose secure measures to provide additional security; and iv) investigate and design a suitable and privacy-preserving federated ML framework for P2P PHSs.
First, the author studied the origins and properties of P2P networks (and PHS). He identified three archetypical P2P network architectures: centralized, decentralized, and hybrid. Based on their characteristics and the requirements for PHS, he proposed a novel but suitable and secure P2P PHS architecture. It has hierarchical relationships between parties like PHS providers, practitioners, and patients, supports an interoperable ecosystem, facilitates processes like user registration and identity authentication, ensures compliance with data regulations, and enhances scalability and resource accessibility.
Second, the author systematically identified and reviewed 49 studies (published between 2008 and 2020) from reliable sources that discuss the inherent security issues of P2P systems. Through thematic data analysis and the foundational information security principles of confidentiality, integrity, and availability, he identified and evaluated eight inherent security issues, such as the Sybil attack, related to PHS design and implementation on P2P networks, alongside seven contributory factors, including the absence of content verification. In addition, the author assessed the chances of exploiting the issues, impact, and risk associated (using a severity scoring system) for the P2P PHS architectures.
Third, the author established a six-phase guideline for provisioning P2P PHSs while maintaining information security. Among the security measures proposed in the guideline phases, effective identity-based authentication should be prioritized during P2P PHS planning and implementation. Consequently, following established methodologies for creating authentication protocols and strengthening password security and access control, he proposed a robust yet secure authentication protocol. This protocol facilitates offline accessibility, employs independent and stateless data encryption keys, and permits patients and healthcare providers to mutually authenticate and exchange data securely. The protocol incorporates a software-based card to streamline the integration of authentication mechanisms in emerging national health-IT infrastructures. Security and performance assessments indicate that the protocol effectively protects against threats and maintains performance on par with conventional, less secure authentication techniques.
Fourth, the novelty and hierarchical nature of P2P PHS architecture poses challenges to the existing federated learning (FL) solutions since they use centralized engines for model update aggregation. Current privacy-preserving techniques used for FL are insufficient since they can only ensure privacy in execution environments. Therefore, he proposed a novel FL framework suitable for P2P PHS multi-tier and hybrid architecture. It increases communication efficiency and scalability and leverages identity-based authentication to ensure end-to-end privacy—by dropping illegitimate clients beforehand and purging their contributions during training.
This dissertation establishes a foundation for understanding P2P (and PHS) system architectures, delineating their merits and demerits. It also proposes a novel architecture adaptable to any PHS provider implementing a secure system. The guideline for securing PHSs on P2P networks on public networks facilitates individual developers and providers to prioritize and deal with potential security issues during the entire system development and maintenance life cycle. The proposed authentication protocol is a foundation for designing and implementing P2P PHSs. At the same time, the secure but scalable FL concepts presented will make the use of ML on P2P PHSs more secure and trustworthy
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