13,356 research outputs found
FIGURE 2 in A new species of Microhyla Tschudi, 1838 (Anura: Microhylidae) from West Coast of India: an integrative taxonomic approach
No full textFIGURE 2. Maximum likelihood tree based on DNA sequences of the 16S rRNA gene showing the phylogenetic relationship among 28 species of genus Microhyla. Numbers on nodes indicate ML bootstrap values. Uperodon variegatus was selected as outgroup. GenBank accession numbers are provided in Table 1.Published as part of Vineeth, Kumar K., Radhakrishna, U. K., Godwin, R. D., Anwesha, Saha, Rajashekhar, K. Patil & Aravind, N. A., 2018, A new species of Microhyla Tschudi, 1838 (Anura: Microhylidae) from West Coast of India: an integrative taxonomic approach, pp. 151-179 in Zootaxa 4420 (2) on page 156, DOI: 10.11646/zootaxa.4420.2.1, http://zenodo.org/record/376975
FIGURE 2 in A new species of Microhyla Tschudi, 1838 (Anura: Microhylidae) from West Coast of India: an integrative taxonomic approach
No full textFIGURE 2. Maximum likelihood tree based on DNA sequences of the 16S rRNA gene showing the phylogenetic relationship among 28 species of genus Microhyla. Numbers on nodes indicate ML bootstrap values. Uperodon variegatus was selected as outgroup. GenBank accession numbers are provided in Table 1.Published as part of Vineeth, Kumar K., Radhakrishna, U. K., Godwin, R. D., Anwesha, Saha, Rajashekhar, K. Patil & Aravind, N. A., 2018, A new species of Microhyla Tschudi, 1838 (Anura: Microhylidae) from West Coast of India: an integrative taxonomic approach, pp. 151-179 in Zootaxa 4420 (2) on page 156, DOI: 10.11646/zootaxa.4420.2.1, http://zenodo.org/record/376975
Sweeping has no effect on renormalized turbulent viscosity
No full textWe perform renormalization group analysis (RG) of the Navier-Stokes equation in the presence of constant mean velocity field , and show that the renormalized viscosity is unaffected by , thus negating the ``sweeping effect", proposed by Kraichnan [Phys. Fluids {\bf 7}, 1723 (1964)] using random Galilean invariance. Using direct numerical simulation, we show that the correlation functions for and differ from each other, but the renormalized viscosity for the two cases are the same. Our numerical results are consistent with the RG calculations
Taylor-Couette flow with asymmetric end-walls boundary conditions
No full textIn the paper the authors present the results obtained during a numerical (Direct Numerical Simulation/Spectral Vanishing Viscosity method - DNS/SVV) and experimental investigations (Kalliroscope, PIV) of the Taylor-Couette flow with asymmetric boundary conditions. In the paper attention is focused on the laminar-turbulent transition process. The main purpose of the research is to investigate the influence of different parameters (aspect ratio, curvature parameter, end-walls boundary conditions) on the flow structure and on the flow characteristics. The transverse current Jω is computed from the velocity field obtained numerically. The λ2 criterion has been used for numerical visualization
Intermittency in Weak Magnetohydrodynamic Turbulence
No full textThree-dimensional incompressible magnetohydrodynamic (MHD) turbulence with a strong uniform magnetic field b0 may be governed by the regime of weak turbulence. At leading order, it is known that the asymptotic regime of weak MHD turbulence is achieved via three-wave resonant interactions with the scattering of two of these waves on a third/2D mode for which k//=0. For zero cross-helicity, the expected exact solution is an energy spectrum in . Higher-order statistics has, however, never been reported in the literature. Therefore, we have recently investigated this question with high resolution direct numerical simulations (Meyrand et al., 2014). We found the presence of strong intermittency when the vector separation of structure functions is taken transverse to b0. This result may be explained by the influence of the 2D modes whose regime belongs to strong turbulence. In addition to shed light on the origin of this intermittency, we derived a log-Poisson law, , which fits perfectly the data and highlights the important role of parallel current sheets
Linear and non-linear vibrations of fluid-filled hollow microcantilevers interacting with small particles
No full textLinear and non-linear vibrations of a U-shaped hollow microcantilever beam filled with fluid and interacting with a small particle are investigated. The microfluidic device is assumed to be subjected to internal flowing fluid carrying a buoyant mass. The equations of motion are derived via extended Hamilton's principle and by using Euler-Bernoulli beam theory retaining geometric and inertial non-linearities. A reduced-order model is obtained applying Galerkin's method and solved by using a pseudo arc-length continuation and collocation scheme to perform bifurcation analysis and obtain frequency response curves. Direct time integration of the equations of motion has also been performed by using Adams-Moulton method to obtain time histories and analyze transient cantilever-particle interactions in depth. It is shown that exploiting near resonant non-linear behavior of the microcantilever could potentially yield enhanced sensor metrics. This is found to be due to the transitions that occur as a matter of particle movement near the saddle-node bifurcation points of the coupled system that lead to jumps between coexisting stable attractors.Accepted Author ManuscriptMicro and Nano Engineerin
Similarities between 2D and 3D convection for large Prandtl number
No full textUsing direct numerical simulations of Rayleigh-B\'enard convection (RBC), we perform a comparative study of the spectra and fluxes of energy and entropy for large and infinite Prandtl numbers in two (2D) and three (3D) dimensions. We observe close similarities between the 2D and 3D RBC, in particular the kinetic energy spectrum , and the entropy spectrum exhibits a dual branch with a dominant spectrum. We showed that the dominant Fourier modes in the 2D and 3D flows are very close
Hydrodynamical turbulence by fractal fourier decimation
No full textWe present a systematic numerical investigation of high-resolution 3D isotropic and homogeneous turbulence resolved on a decimated set of Fourier modes. Fractal decimation acts to decrease the effective dimensionality of the flow by allowing triadic interactions only in a set of Fourier modes N(k) proportional to k^DF for large k. While keeping the symmetries of the original 3D Navier-Stokes equations unchanged, a dramatic change in small-scale statistics is detected at decreasing the fractal dimension DF . Already at fractal dimension DF = 2.8, a global self-similar behaviour is observed in the inertial range of scales, the consequence of such transition are the restoration of the scaling symmetry and vorticity distribution that becomes close to Gaussian. We relate the results to the different roles of local vs non-local interactions in the energy transfer range
Microhyla kodial Vineeth & Radhakrishna & Godwin & Anwesha & Rajashekhar & Aravind 2018, sp. nov.
No full textMicrohyla kodial sp. nov. (Fig. 3 A & B) Zoobank ID. urn:lsid:zoobank.org:pub: B78E690B-D70D-44CF-B88B-F2023A22F78D Holotype. NCBS-AY587, an adult female collected from marshy areas in Baikampady, Mangaluru, Dakshina Kannada District, Karnataka, India (12.9518 o N, 74.8089 o E; alt 6 m amsl), by VKK, RUK and NAA, 20:00–22:00 h on 28 th September 2016. Suggested common name: Mangaluru narrow-mouthed frog Etymology. This species is named after Mangaluru city, coastal city of Karnataka, India from where the species has been collected. Mangaluru is known as Kodial in Konkani language. The specific name is an invariable noun in the nominative singular in apposition to generic name. Paratypes. Four females (NCBS-AY588 to NCBS-AY591 ) and five males (NCBS-AY592 to NCBS-AY596), collected from the type locality on 28 th September 2016 between 20:00-22:00h by VKK, RUK and NAA. Diagnosis. The new species is assigned to Microhylidae by the possession of median spiracle in the tadpole stage (Matsui et al. 2013), and to the genus Microhyla owing to the following set of diagnostic characters as described by Parker (1934), Inger (1989) Matsui et al. (2013), Wijayathilaka et al. (2016), Seshadri et al. (2016a) & Khatiwada et al. (2017): Small sized adults with slender body and narrow head; eyes reduced with circular pupil; lack of small spine-like projection of skin at heel and elbow; supratympanic fold present; fingers without webbing; toes with basal webbing; vomerine teeth absent; tongue obovate, entire and free at the base; snout less than twice the diameter of eye; indistinct canthus rostralis; tympanum hidden by skin; palmar tubercles distinct; distinct ovoid shaped inner metatarsal tubercle and rounded outer metatarsal tubercle. Microhyla kodial sp. nov. can be distinguished from all other Microhyla from South and Southeast Asia by the following set of characters: (i) A small sized frog (SVL; male: 16.9–17.4 mm, n = 5 and female: 18.0– 20.4 mm, n = 5); (ii) snout rounded in dorsal and ventral view, canthus rostralis indistinct, snout protrudes beyond mouth in ventral view; (iii) tongue obovate with tip pointed, margin smooth, lingual papilla absent; (iv) absence of lateral dermal fold (dark band) from behind the eye to groin; (v) absence of vertebral stripe (dorsal median line); (vi) absence of superciliary tubercles; (vii) tympanum indistinct hidden by skin; (viii) supratympanic fold present; (ix) head triangular, wider than long; (x) olive-green band on head, forms an arch at about half-length of upper eyelid between the eyes, this distinct band continues as a pattern on dorsum till the vent; (xi) skin tuberculated on dorsum, venter smooth; (xii) grayish-black throat in males; (xiii) first finger is longer than half the length of second finger; (xiv) finger and toe disc without dorsal median groove; (xv) palmar tubercles are well developed, with outer being round and large and inner small and ovoid; (xvi) webbing is absent between the fingers, webbing between the toes is basal; (xvii) inner and outer metatarsal tubercle present, inner metatarsal tubercle is ovoid, half the length of outer metatarsal tubercle which is almost rounded in shape. Description of holotype (Voucher No. NCBS–AY587, measurements in mm, Fig. 4 A–K; Table 2). Smallsized, adult female (SVL = 18.3). Head small, triangular, wider than long (HW = 4.5; HL = 4.0). Snout acute and rounded in both dorsal and ventral views; rounded in lateral view, upper jaw protrudes slightly in ventral view. Snout length (SL = 2.2) 1.22 times longer than the horizontal diameter of the eye (EL = 1.8). Canthus rostralis indistinct, loreal region concave. Interorbital space sloping towards snout, 1.9 times larger than maximum width of upper eyelid and 1.36 times wider than internarial distance (IUE = 1.9; UEW = 1.0; IN = 1.4). The distance between posterior margins of eyes 1.47 times that of anterior margins (IBE = 4.4; IFE = 3.0). Nostrils are rounded, without any flap, closer to tip of snout than to eye (NS = 0.7; EN = 1.4). Tongue relatively large, obovate, free at base and with smooth margin, lingual papilla absent. Vomerine ridge absent. Tympanum indistinct, supratympanic fold prominent; extending from posterior corner eye to near the insertion of forelimb axilla. Eyes small (EL = 1.8), pupil-rounded. Paratype 5 Paratype 6 Paratype 7 Paratype 8 Paratype 9 Mean±SD Holotype Paratype 1 Paratype 2 Paratype 3 Paratype 4 Mean±SD (592) (593) (594) (595) (596) (587) (588) (589) (590) (591) Male Male Male Male Male Female Female Female Female Female SVL 16.9 17.2 17.4 16.9 17.4 17.16±0.25 18.3 19.2 18 20.4 19.9 19.16±1.02 HW 4.3 4.4 4.3 4.4 4.5 4.38±0.08 4.5 4.7 4.8 4.6 4.7 4.66±0.11 HL 4 3.9 3.8 4 3.9 3.92±0.08 4 4.1 4.2 4.2 4.3 4.16±0.11 HD 2.4 2.1 2.7 2 2.1 2.26±0.28 2.7 2.6 2.6 2.6 2.7 2.64±0.05 IUE 1.8 1.8 1.9 1.7 1.6 1.76±0.11 1.9 2.2 2.1 2 2.1 2.06±0.11 UEW 0.9 1.1 1.2 0.9 1 1.02±0.13 1 1 1.1 1.1 1.2 1.08±0.08 SL 2.5 2.1 2.3 2 1.9 2.16±0.24 2.2 2.2 2.1 2.1 2 2.12±0.08 EL 1.6 1.5 1.8 1.6 1.5 1.6±0.12 1.8 2 1.9 1.7 1.9 1.86±0.11 MN 3.5 2.9 3.4 3 3.1 3.18±0.25 3.9 3.6 3.2 3.4 3.5 3.52±0.25 MFE 2.9 2.4 2.9 2.3 2.2 2.54±0.33 2.4 2 2.3 2.3 2.1 2.22±0.16 MBE 2.1 1.3 1.5 1.7 1.6 1.64±0.29 1.7 1.6 1.7 1.5 1.3 1.56±0.16 IN 1.3 1.4 1.4 1.4 1.4 1.38±0.04 1.4 1.4 1.5 1.5 1.4 1.44±0.05 IFE 3.1 3 3.1 2.9 2.7 2.96±0.16 3 3.1 3.1 3.3 2.9 3.08±0.14 IBE 4.2 4.2 4.4 4.1 4.1 4.2±0.12 4.4 4.6 4.5 4.6 4.8 4.58±0.14 NS 0.7 0.6 0.7 0.7 0.7 0.68±0.04 0.7 0.9 0.8 0.7 0.8 0.78±0.08 EN 1.4 1.4 1.3 1.2 1.3 1.32±0.08 1.4 1.2 1.2 1.2 1.3 1.26±0.08 FLL 2.5 2.6 2.7 2.4 3 2.64±0.23 3.1 3.2 2.9 3.1 3 3.06±0.11 HAL 3.5 3.8 3.5 3 3.8 3.52±0.32 3.9 4.1 3.5 2.7 3.9 3.62±0.55 FD1 0.1 0.2 0.1 0.1 0.2 0.14±0.05 0.1 0.2 0.1 0.2 0.2 0.16±0.05 FD2 0.2 0.3 0.2 0.2 0.2 0.22±0.04 0.2 0.2 0.2 0.3 0.3 0.24±0.05 FD3 0.3 0.2 0.2 0.2 0.1 0.2±0.07 0.3 0.2 0.2 0.2 0.3 0.24±0.05 FD4 0.2 0.2 0.2 0.2 0.2 0.2±0 0.3 0.3 0.2 0.3 0.3 0.28±0.04 FW1 0.1 0.1 0.1 0.2 0.1 0.12±0.04 0.1 0.2 0.1 0.2 0.2 0.16±0.05 FW2 0.2 0.2 0.2 0.2 0.2 0.2±0 0.2 0.2 0.2 0.3 0.3 0.24±0.05 FW3 0.2 0.2 0.2 0.2 0.1 0.18±0.04 0.2 0.2 0.2 0.3 0.3 0.24±0.05 FW4 0.2 0.1 0.2 0.2 0.2 0.18±0.04 0.2 0.2 0.2 0.3 0.3 0.24±0.05 FIL 0.6 0.7 0.6 0.6 0.6 0.62±0.04 0.8 0.7 0.7 0.9 0.8 0.78±0.08 ……continued on the next page Forelimb shorter than hand length (FLL = 3.1; HAL = 3.9). Fingers short, relative lengths of fingers I<II<IV<III (FIL = 0.8; FIIL = 1.2; FIII L = 2.1; FIVL = 1.7). Discs on fingertips are not prominent and are seen only on third and fourth finger (FD1 = 0.1, FD2 = 0.1, FD3 = 0.3, FD4 = 0.3; FW1 = 0.1, FW2 = 0.2, FW3 = 0.2, FW4 = 0.2). Foot discs are devoid of dorsal median groove. Ventral median grooves present in each finger, rising from the distal end, distal notch is conspicuous. Webbing between fingers absent. Palmar tubercles well developed and distinct; outer palmar tubercle is large and round, the inner palmar tubercle is small and ovoid. Subarticular tubercles distinct and are ovoid in shape (finger: i = 1, ii = 1, iii = 2, iv = 2). Nuptial pad is absent. Hind limbs are longer than forelimbs. Shank 2.97 times longer than wide (ShL= 8.6, TW= 2.9), longer than thigh length (TL = 8.0) and shorter than foot length (FOL = 9.1). Heel to tip of fourth toe (TFOL= 12.9) about 2.39 times longer than fourth toe length (TIVL = 5.4). Relative toe length I<II<V<III<IV (TIL = 1.1; TIIL = 2.0; TIIIL = 3.5; TIVL = 5.4; TVL = 3.2). Toe tips are dilated (TD1 = 0.2, TD2 = 0.3, TD3 = 0.4, TD4 = 0.4, TD5 = 0.3; ToW1 = 0.2, ToW2 = 0.2, ToW3 = 0.3, ToW4 = 0.3, ToW5= 0.2). Toe discs are devoid of dorsal median groove. Ventral median groove is present on toes. Webbing between toes is basal, does not extend beyond the base of proximal subarticular tubercle. Metatarsal tubercles well developed and distinct. Inner metatarsal tubercle is ovoid, half the length of (IMT = 0.5) outer metatarsal tubercle which is rounded in shape (OMT = 1.0). Subarticular tubercle present (toe: i = 1, ii = 1, iii = 2, iv = 3, v = 2). Skin texture and colour in preservative. Skin of dorsum, snout, between eyes, sides of head, upper part of flanks, forelimbs and hind limbs is slight to moderately tuberculated; ventral skin is smooth. Dorsal coloration pale gray; upper eyelid is dark gray in color. A light olive-green band between the eyes. Forelimbs and hind limbs light brown with dark brown cross bands. Cross bands are distinct in shank and foot. Ventral region pale cream colored; throat has white blotches near the margins of lower jaw and lower margin of the upper jaw; light yellow pigmentation at the junction of forelimbs. Limbs are pale in color compared to the body. Skin texture and color in life. Skin has small to medium sized tubercles all over the dorsum, faint tubercles on foot (not visible in preserved specimens). Skin on the underside is smooth. Overall grayish-brown in color with thick dark olive-green band on head, forming an arch at about half-length of upper eyelid between the eyes, this distinct band continues as a pattern on dorsum till the vent. Dark olive-green to dark-brown cross bands are prominent in forearm, feet, thigh, shank and toes. Supratympanic fold shows black pigmentation. Iris brown/black with golden yellow mottles. Pupil black. Ventral parts creamish-white throughout. Variation. Sexes dimorphic, females larger than males (SVL: males, 16.9–17.4 mm, n = 5; females, 18.0– 20.4 mm, n = 5). Grayish-black subgular vocal sac present in males. Gravid females contained un-pigmented eggs, which were visible in the belly near the groin. Advertisement call description. Microhyla kodial sp. nov. makes characteristic sounds with continuous notes ‘Ttrrrt…… ttrrrt….ttrrrt….’. It is observed that there are 2 to 7 pulses in each call (6±2 pulses, n= 50) with pulse rate of 14.97±1.38 pulses/s. Average dominant frequency was 3752.16±233.06 Hz (range: 3359.20–4220.50 Hz) and call duration was 0.33± 0.07 s. (range: 0.11– 0.42 s.). Waveform and spectrogram of sample calls of Microhyla kodial sp. nov. is shown in Fig. 5. Summary statistics for call characteristics is given in the Table 4. A video clip of advertisement call of M. kodial is at https://youtu.be/B0Bj8xWng8kPublished as part of Vineeth, Kumar K., Radhakrishna, U. K., Godwin, R. D., Anwesha, Saha, Rajashekhar, K. Patil & Aravind, N. A., 2018, A new species of Microhyla Tschudi, 1838 (Anura: Microhylidae) from West Coast of India: an integrative taxonomic approach, pp. 151-179 in Zootaxa 4420 (2) on pages 156-161, DOI: 10.11646/zootaxa.4420.2.1, http://zenodo.org/record/376975
Inter-vortex spacing in superfluid turbulence: temperature and Reynolds number dependences
No full textThe typical spacing between superfluid vortices in an isothermal turbulent tangle is proportional to the integral scale H rescaled by the quantum Reynolds number Re_K=H.V/K to the power of 3/4, where K is the quantum of circulation around of single vortex [Salort et al.,EPL 2011]. This empirical relation can be seen as the quantum-turbulence version of the corresponding well-know equation giving Kolmogorov dissipative scale in classical turbulence. In 2014, we studied the temperature dependence of the numerical factor (d/H).Re_K^{3/4} in 4He by joint numerical and experimental analysis of steady state turbulence over a wide temperature interval (1.2 - 2.16 K) [Babuin et al., EPL 2014]. Agreement between the two analyses was found good except at the very ends of this temperature interval. We will discuss this issue by presenting additional experimental data obtained by post-processing of superfluid experiments published between 1975 and 1998
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