4,444 research outputs found
Solar and Sterile Neutrino Physics with the Raghavan Optical Lattice
No full textThe neutrino is, by its nature, an elusive particle that requires massive detectors with small backgrounds to capture a handful of events. Nevertheless, neutrino experiments stand at the heart of the current mysteries of particle physics and astrophysics. These include the origin and size of neutrino mass, the existence of additional types of neutrinos, CP violation and the matter--antimatter asymmetry, the amount of metals in the Sun's core, and the existence of non-nuclear energy sources in the Sun. This dissertation concerns the the use of a novel detector technology, the Raghavan Optical Lattice (ROL), in the Low-Energy Neutrino Spectrometer (LENS) and Neutrino Lattice (NuLat) experiments. LENS will measure the solar neutrino luminosity and the Sun's core metallicity using a ROL with indium-loaded liquid scintillator. NuLat will probe the existence of light sterile neutrinos with masses of using a ROL made from -loaded plastic scintillator. For LENS we present an overview of the experiment and the present the ROL construction results from the LENS R\andD program. In particular we will present results from the micro- and mini-LENS prototypes. For both LENS and NuLat we present the development of an event reconstruction algorithm for ROLs and we apply these to the expected signals for these experiments. For NuLat we present an overview of the experiment including its theory of operation and its sensitivity to sterile neutrino oscillations. Finally, we present work toward the full-sized NuLat detector through bench-top tests and construction of the NuLat demonstrator.Ph. D
The effects of financial liberalization on monetary policy : the Malaysian experience / Mala @ Valliammai a/p R. M. Raghavan.
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Pangio pathala Arjun & Sidharthan & Dahanukar & Raghavan 2022, new species
No full textPangio pathala, new species (Fig. 1) Holotype. KUFOS.FT.2020.1, 32.1 mm SL; India: Kerala: Thiruvanvandoor (9°20’23.09”N, 76°34’48.54”E), 7 m asl., coll. R. Sundar, A. Sidharthan & C. P. Arjun, 25 October 2020. Paratype. KUFOS.FT.2020.2 (c&s), 18.9 mm SL; same data as holotype; KUFOS.FT.2020.3, 22.3 mm SL; India: Kerala: Thiruvanvandoor (9°20’23.09”N, 76°34’48.54”E), 7 m asl., coll. R. Sundar, A. Sidharthan & C. P. Arjun, 11 November 2020. Diagnosis. Pangio pathala is distinguished from all other species of Pangio (except P. bhujia) by the absence of the dorsal fin (vs. presence), presence of four pectoral-fin rays (including an unbranched rudimentary ray) (vs. 5–11), 13 segmented (both branched and unbranched) caudal-fin rays (vs. 14–16), and a unique count of 27 caudal vertebrae (vs. 11–20), the highest among the known members of the genus. Pangio pathala is further distinguished from all other species of Pangio except P. bhujia, P. fusca, P. apoda, P. pulla and P. lidi by the absence of pelvic fins. Pangio pathala differs from its only subterranean congener, P. bhujia, in having four pectoral-fin rays (vs. three); five anal-fin rays (vs. six); greater number of vertebrae (67 vs. 62–63); and a raw genetic distance of 8.1–8.7% in the mitochondrial co1 gene. Description. Morphometric and meristic data are presented in Table 1. Body elongate, oval in cross section, strongly compressed laterally in caudal region.Standard length 14.2–18.2 times body depth; body depth 1.1–1.8 times body width. Caudal peduncle laterally compressed, long, its length 3.6–5.4 times its depth, its depth 2.4–4.4 times its width. Precaudal adipose keels well-developed, deep, long; dorsal adipose keel originating anterior to vertical from anal-fin origin; adipose keel of ventral profile originating immediately posterior to anal-fin base. Scales absent. Head rounded, small, about 10.5–13.1% SL. Eyes small, 4.8–6.5% HL. Mouth subterminal; with three pairs of elongated barbels. Two pairs of maxillary barbels, outer maxillary barbel reaching beyond posterior border of eye; inner maxillary barbel reaching between eye and nare. One pair of mandibular barbels, reaching anterior border of eye. Posterior margin of anterior naris developed into a long (47.53–58.61% HL), pointed flap, referred to as nasal barbel. Pectoral fin narrow, long, thread-like, with four rays including an unbranched rudimentary ray. Anal fin short with rounded margin, with one rudimentary ray followed by four unbranched rays. Pelvic fin and girdle absent. Dorsal fin and dorsal-fin pterygiophores absent. Caudal fin pointed, with both segmented and unsegmented, but unbranched rays: 4 dorsal unsegmented +6 dorsal segmented + 7 ventral segmented + 2 ventral unsegmented rays. Ribs on vertebrae 5–40. Total vertebrae 67 = 40 abdominal + 27 caudal vertebrae. Colouration. In life, body pinkish-red to light pink when freshly collected, becomes brownish pink in captivity, slightly darker on dorsal profile, ventral profile translucent. Eye a tiny small black spot. Caudal region translucent, rendering caudal vertebrae visible. Pectoral, anal, and caudal fins hyaline (Fig. 1a). In preservative, body pale yellowish-white with tiny black eye. Dorsal side of head and body with scattered minute melanophores only visible at 20× magnification. Distribution and habitat. Currently, Pangio pathala is known only from its type locality, Thiruvanvandoor, near the town of Chengannur, Kerala State, India (Fig. 2). Specimens were collected from an overhead water-storage tank connected to an old dug-out well using an electric water pump. The well is approximately 17 feet deep, and drawn water was used for drinking and household activities (Fig. 3). Etymology. The species name is based on the Sanskrit word pâtâla, which means ‘below the feet’, denoting the subterranean realms of the universe—which are located under the earth’s surface. A noun in apposition. Genetic analysis. In the maximum likelihood analysis based on the co1 gene, Pangio pathala and P. bhujia are sister species and form a clade with the other Western Ghats congeners (Fig. 4). Pangio pathala differs from P. bhujia by a raw genetic distance of 8.1–8.7%, and from all its other congeners for which genetic data (mitochondrial co1) are available, by a raw genetic distance of 14.4–19.5% (Table 2). New distribution record for Pangio bhujia. We also take this opportunity to record two specimens of P. bhujia from Indianoor (10°58’56.20”N, 76°2’32.51”E, 37 m. asl) near the town of Kottakkal. The two fish were collected from a shallow channel (<0.1 m depth) originating in a nearby pond (<2 m depth) used for irrigation. The substrate of the channel comprised of laterite soil covered by fallen, decayed leaves. The habitat is similar to the type locality of P. bhujia, which is located around 40 km north. Detailed morphological examination of the specimens, and comparison of its co1 gene sequence, confirmed its conspecificity with P. bhujia (Table 1 and Fig. 4). Co-occurring species in the channel and pond include Lepidocephalichthys thermalis, Pseudosphromenus cupanus, Rasbora dandia, Aplocheilus lineatus, and Puntius vittatus.Published as part of Arjun, C. P., Sidharthan, Arya, Dahanukar, Neelesh & Raghavan, Rajeev, 2022, A new diminutive subterranean eel loach species of the genus Pangio (Teleostei: Cobitidae) from Southern India, pp. 89-97 in Zootaxa 5138 (1) on pages 90-93, DOI: 10.11646/zootaxa.5138.1.9, http://zenodo.org/record/655224
Aenigmachanna gollum Britz & Anoop & Dahanukar & Raghavan 2019, new species
No full textAenigmachanna gollum, new species Figures 1–4 Holotype. BNHS FWF 966, 90.2 mm SL, Oorakam, Malappuram, Kerala, India (11°03’52’’N and 76°01’00’’E) collected by Ajeer on 3 September 2018 from a paddy field. Paratype. BNHS FWF 967, 80.1 mm SL, same information as for holotype. Diagnosis. Same as for the genus. Description. Body cylindrical anteriorly to subcylindrical posteriorly and laterally compressed caudally, elongate, eel-like (Figs. 1,2), its length 8.8–9.0 times its depth, tapering towards tail, where body length is 22–23 times its depth. Head large, with eye situated in anterior third of head. Nasal organ large, about 1/10 head length, anterior naris at end of elongate nasal tube, posterior naris a large opening in front of eye. Mouth large (Figs. 1-3), jaw length nearly 2/3 head length. Premaxilla with several rows of strong recurved teeth, larger near symphysis and smaller and only in single row more posteriorly. Vomer with up to 10 strong conical teeth, six prominent teeth on palatine arranged in a single row. Dentary with several rows of smaller but strong and recurved teeth on patch near symphysis, but with larger caniniform teeth further posteriorly. Five large antrorse teeth on posterior patch of parasphenoid. Fifteen elongate gill rakers on external aspect of first gill arch. Five branchiostegal rays. Head lateral-line pore system with two nasal pores, seven circumorbital pores, two frontal pores, four dentary and one anguloarticular pore, four preopercular pores, one pterotic pore, two extrascapular pores, one posttemporal pore. No pored lateral line scales on body (Fig. 4). Dorsal fin long (Figs. 1,2), nearly three-quarters of standard length, originating at first quarter of body, extending to caudal peduncle, almost reaching caudal fin. Anal fin long (Figs. 1,2), more than half of standard length, originating slightly behind first half of body and in posterior extension mirroring dorsal fin by extending almost up to caudal fin. Caudal fin ovoid (Fig. 1). Pectoral fin large, its posterior margin when adpressed reaching beneath origin of eighth dorsal-fin ray (Fig. 1,2). Pelvic fin absent. Morphometric information is presented in Table 1. Large scales covering top of head, small scales on postorbital area up to opercle (Figs. 2,3). 29 (10 + 19) predorsal scales. Comparatively small scales on anterior postcranial portion of body arranged slightly irregularly, with larger regularly arranged scales from level of anterior dorsal fin base posteriorly. 83–85 scales in lateral series plus 4 scales on caudal-fin base. 13 transverse scale rows. Dorsal fin with 56–57 rays, anal fin with 43–44 rays, caudal fin with 7+7 principal caudal-fin rays and 1 dorsal and 1 ventral procurrent ray. Pectoral fin with 12 rays. Vertebrae 64. Unfortunately, due to the rarity of the material we are unable to comment further on internal features. Colouration. In life (Fig. 1), entire body from head to caudal peduncle uniformly brown dorsally and mostly brown laterally, but with ventral side of head uniformly lighter beige without melanophores; abdominal area mostly beige with scattered dark spots. Scales covering cheek and opercular region exhibiting reflective, silvery areas resulting in a marbled impression. Body at level of individual scales with characteristic colouration (Figs. 1–4): each scale in dorsal half of body with darker brown anterior crescentic area, light brown to yellowish, narrow and crescentic, elongate marking in middle of scales and dark brown posterior blotch-like marking; scales in ventral half of body with light brown to yellowish crescentic mark becoming progressively wider ventrally, in ventrolateral scales entirely replacing anterior dark crescentic area; most scales in ventral abdominal region uniform beige with few brown scales interspersed, forming scattered spots, some of which are arranged in a midventral streak from isthmus to anus. Fin membranes transparent and fin rays light brown with whitish distal tips forming narrow whitish dorsal, caudal, and anal-fin margins. In preservative, colour pattern as above, but reflective silvery area on cheek scales, light brown area on body scales, and beige scales on ventral abdominal body whitish. Distribution. Aenigmachanna gollum is so far known only from the type locality (Figs. 5,6), a paddy field, but a third specimen has been reported from a well at the Village of Peringara near Tiruvalla (9°22’33” N and 76°33’00” E), approximately 250 km south of the type locality. Etymology. Named after Gollum, a character from J. R. R. Tolkien’s books ‘The Hobbit’ and ‘The Lord of the Rings’, a creature that went underground and during its subterranean life changed its morphological features. A noun in apposition. We propose the common name Gollum snakehead for this species. Genetic analysis. Aenigmachanna showed high genetic divergence, with minimum and maximum raw genetic distances ranging from 15.8–24.2% in cox1 for the species of Channa, and with 20.4–22.2% in cox1 for species of Parachanna. Best partition scheme for the data was TNe+I+G4 for first two codon positions of cox1 (BIC = 18328.676, lnL = -8606.791, df=172) and TN+ASC+G4 for third codon position of cox1 (BIC = 18714.922, lnL = -8511.415, df=261). The maximum likelihood tree based on the best partition scheme (Fig. 7) showed a deep divergence between Aenigmachanna gollum and the clades of Parachanna and Channa within Channoidei. Additional studies are needed to place Aenigmachanna gollum with confidence into a phylogenetic framework and to decide whether it is the sister group of Parachanna, of Channa or even of Parachanna plus Channa, as in the cox1 analysis (Fig. 7).Published as part of Britz, Ralf, Anoop, V. K., Dahanukar, Neelesh & Raghavan, Rajeev, 2019, The subterranean Aenigmachanna gollum, a new genus and species of snakehead (Teleostei: Channidae) from Kerala, South India, pp. 377-388 in Zootaxa 4603 (2) on pages 379-382, DOI: 10.11646/zootaxa.4603.2.10, http://zenodo.org/record/268232
Stiffness and echogenicity: Development of a stiffness-echogenicity matrix for clinical problem solving
No full textThe assessment of soft tissue stiffness is important to evaluate many neuromusculoskeletal conditions. Several tools have been proposed for the assessment of stiffness, but ultrasonography appears to be most practical. The reflection of ultrasound waves as it travels through tissue enables assessment of tissue echogenicity, which is influenced by the characteristics of the sound wave as well as the characteristics of the tissue through which it passes, such as the amount of fat and fibrous tissue. However, tissue stiffness is not directly proportional to its echogenicity. Hence evaluation of echogenicity, as a stand-alone technique, is inadequate to describe its mechanical properties. The aim of this manuscript is to present a method of combining echogenicity evaluation by ultrasound and stiffness evaluation by palpation to better describe the mechanical properties of muscle using a stiffness-echogenicity matrix
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