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SUMMARYThe Flores thrust forms the west segment (∼450 km) of a very active, ∼E–W striking, ∼800-km-long backarc thrust along the east Sunda Arc. In 2018, a deadly earthquake sequence composed of ~110 M4+ events rattled the Indonesian island of Lombok near the Flores thrust and caused tremendous damage on the island, however what is the nature of rupturing during this earthquake sequence remains unknown. Here, using a total of 2120 km of high-resolution seismic profiles covering ∼300 km of the Flores thrust off Bali, Lombok and Sumbawa, in addition to earthquake data and InSAR measurements, we investigated the active thrusting during this earthquake sequence. Our seismic interpretation and structural mapping show that offshore north of Lombok and Bali, the remarkable Flores thrust is essentially blind, deforming the seabed by folds, not faults. The Lombok earthquakes were all shallow thrust events with depth 7) that occur directly on the offshore blind thrusts, not beneath the island like the Lombok sequence. The proximity of the Rinjani volcano and thrust earthquakes suggests a possible role of volcanic activity (e.g. magmatic fluids and gas migration, stress change induced by pressurized magma chamber) in inducing the Lombok earthquakes.

The uppermost oceanic crust composes of Layers 2A and 2B, and the boundary between them is debated to be a lava/dike transition or a hydrothermal alteration boundary within the lava unit. Here, we present the analyses of ultralong multichannel seismic data along a 1,500 km long profile covering 0–75 Ma of the oceanic lithosphere on the African plate in the equatorial Atlantic Ocean. We find that the Layer 2A is observed along the whole profile, with its urn:x-wiley:ggge:media:ggge22094:ggge22094-math-0001 velocity increasing from 2.5 km/s near the ridge axis to urn:x-wiley:ggge:media:ggge22094:ggge22094-math-00024 km/s at urn:x-wiley:ggge:media:ggge22094:ggge22094-math-00034 Ma with slight variations thereafter. We also find that the sediment thickness increases rapidly from 0 m at the ridge axis to 170 m at 4 Ma, suggesting that there is a link between the high sedimentation rate and the increase in Layer 2A velocity. These observations indicate that crust younger than 4 Myr may be influenced by active hydrothermal circulation. The observed thickness of Layer 2A decreases from urn:x-wiley:ggge:media:ggge22094:ggge22094-math-0004850 m near the ridge axis to urn:x-wiley:ggge:media:ggge22094:ggge22094-math-0005600 m at 15 Ma with no significant changes beyond. We also find an increase in Layer 2B velocity from 5.1 km/s at 4 Myr to 5.5 km/s at 46 Myr, suggesting that passive hydrothermal circulation may extend deeper than Layer 2A/2B boundary. We propose Layer 2A/2B boundary to be a lava/dike transition at the ridge axis and a hydrothermal alteration boundary within the extrusive section away from the ridge axis. Published version

Lithosphere-asthenosphere boundary (LAB) has generally been estimated using surface tomography (Priestley and McKenzie, 2006; Auer et al., 2014), surface waves anisotropy (Plomerova et al, 2002; Burgos et al., 2014) and receiver function methods (Kumar and Kawakatsu, 2011; Rychert et al., 2012), indicating a change in the S-wave velocity. Recently, some limited studies have shown that LAB could be imaged using seismic reflection imaging method (Stern et al., 2015; Mehouachi and Singh, 2018), requiring a sharp P-wave velocity contrast. Here, we present a continuous seismic reflection image of the LAB from 2-to-75-Ma in the Equatorial Atlantic Ocean over the African plate along a 1400 km long profile using a 12 km long offset multi-channel multi-component (hydrophone and three component acceleration) seismic data. Optimal de-ghosting by summation of pressure (P) and vertical acceleration (Az) components has improved the bandwidth of the data by removing the notches (Vassallo et al., 2013). Further advanced processing consisted of noise removal in shot and receiver domains followed by low frequency boost-up. Trace interpolation followed by wavenumber filtering was performed in the common-midpoint domain to achieve a higher signal-to-noise ratio and flat events enhancement. Post-stack processing mainly consisted of frequency-space deconvolution, dip filtering and data-adaptive edge-preserving modified Kuwahara filter. We find two prominent reflections: The upper varies from ~12 km (3.5 s) two-way time (TWT) below the seafloor at 2 Myr to ~78 km (20 s) TWT below the seafloor at 75 Myr. For 27-to-47-Myr old lithosphere, we image a second almost flat continuous reflection from 21 s to 22 s TWT below the seafloor (~82 km). This event is not prominent for 49-to-75-Myr old lithosphere, probably due to the influence of the mantle thermal anomalies from St.Helena/Cameroon. There is also evidence of some other reflections between these two reflections, which also dip towards older age. The crust-mantle boundary or the Moho is also fairly imaged throughout the profile with crustal thickness ranging between 1.4 – 2.7 s TWT. We interpret the uppermost reflection as the base of lithosphere, the top of the LAB, and the lower reflection as the base of the LAB, while the reflections between these as sheared melt sheets. Our results provide the very first image of the whole LAB system continuously as it deepens and thins away from the ridge axis. In this presentation, we will discuss different implications of these images and provide a comprehensive model of the oceanic LAB over normal oceanic lithosphere.

The northern Indian Ocean has been widely recognized as an area of broadly distributed deformation within the composite India‐Australia‐Capricorn plate, hosting several diffuse boundary zones and a diffuse triple junction. The occurrence, along reactivated fracture zones, of the exceptionally large (Mw=8.6 and Mw=8.2) 2012 Wharton Basin strike‐slip earthquakes, however, questions whether this composite plate is breaking apart along a discrete boundary. Using recent bathymetric and seismic data, we analyze the most prominent fracture zone (F6a), whose structural trace is particularly well‐expressed. We identify sixty kilometric‐scale pull‐apart basins with geometric properties (length/width ratios) similar to those observed along continental strike‐slip plate boundaries. Four of the pull‐aparts formed above narrow, sub‐vertical faults extending into the oceanic crust. Within the broad Wharton deformation zone, the significant slip rates (0.8 to 2.5 mm/yr) and unusually large co‐seismic displacements recorded along F6a suggest that it may be a nascent plate boundary. Plain Language Summary Oceanic plates are usually rigid and aseismic, except along their boundaries. In 2012, two extraordinary earthquakes with magnitudes M>8, typical of plate boundary events, occurred in the Wharton Basin, inside the India‐Australia‐Capricorn plate, slicing the seafloor along straight, old fracture zones bearing evidence of active tectonic deformation. Using submarine relief and seismic data, we study the freshest fracture zone (F6a) to examine whether it might qualify as a nascent plate boundary between India and Australia. We find that localized cracks along it and narrow rectangular basins (pull‐aparts) resemble those along large continental strike‐slip boundary faults, supporting the inference that the composite Indo‐Australian plate is breaking apart. Key Points Sixty kilometric‐scale, pull‐apart basins show aspect ratios similar to those observed along crustal‐scale strike‐slip faults At least four deep pull‐aparts rooted into lithospheric faults illustrate a progressive localization of deformation along F6a Sinistral slip rates < 2 mm/yr and exceptionally large 2012 co‐seismic slip support the evolution of F6a into a nascent plate boundary

SUMMARY Full waveform inversion (FWI) is a powerful method to estimate high-resolution physical parameters of the subsurface by iteratively minimizing the misfit between the observed and synthetic seismic data. Standard FWI algorithms measure seismic misfit between amplitude-preserved seismic data (true-amplitude FWI). However, in order to mitigate the variations in sources and recording systems acquired on complex geological structures and the physics that cannot be modelled using an approximation of the seismic wave equation, the observed and synthetic seismic data are normalized trace-by-trace and then used to perform FWI. Trace-by-trace normalization removes the amplitude effects related to offset variations and only keeps the phase information. Furthermore, trace-by-trace normalization changes the true amplitude difference because of different normalization factors used for the corresponding synthetic and observed traces. In this paper, we study the performance of true-amplitude FWI and trace-normalized-residual-based FWI in the time domain. The misfit function of trace-normalized-residual-based FWI is defined such that the adjoint source used in gradient calculation is the trace-normalized seismic residual. We compare the two inversion schemes with synthetic seismic data simulated on laterally invariant models and the more complex 2-D Marmousi model. In order to simulate realistic scenarios, we perform the elastic FWI ignoring attenuation to noisy seismic data and to the synthetic data modelled using a viscoelastic modelling scheme. Comparisons of seismic data and adjoint sources show that trace-by-trace normalization increases the magnitude of seismic data at far offsets, which are usually more cycle-skipped than those at near offsets. The inverted results on linear-gradient models demonstrate that trace-by-trace normalization increases the non-linearity of FWI, so an initial model with sufficient accuracy is required to guarantee the convergence to the global minimum. The inverted results and the final seismic residuals computed using seismic data without trace-by-trace normalization demonstrate that true-amplitude FWI provides inverted models with higher accuracy than trace-normalized-residual-based FWI, even when the unknown density is updated using density–velocity relationship in inversion or in the presence of noise and complex physics, such as attenuation.

Published slip distribution models, based on geodetic, seismological and tsunami data, of the Mw 7.8, 2010 Mentawai tsunami earthquake offshore south-central Sumatra, suggest that the large tsunami wave was generated by a narrow swath of high seafloor uplift along the accretionary wedge front, implying higher vertical throw than that consistent with slip on the shallow-dipping megathrust. Here we present high-resolution seismic reflection profiles across the 2010 rupture zone that image the youngest deformation at the accretionary wedge front. The profiles reveal conjugate, steeply-dipping, active thrust faults that branch upwards from the megathrust and bound triangular pop-ups. The seismologically determined co-seismic slip (≥10 m) on the 6°-dipping decollement probably caused a comparable amount of upward expulsion of these ∼3 km–wide, flat-topped pop-ups. Co-seismic throw on the ≈60° dipping thrusts that bound the pop-up plateaus maximize the uplift of the seafloor and overlying water-column, providing an additional localised tsunami source. Tsunami simulations show that such combined deformation, i.e. the broad-scale seafloor displacement caused by slip on the megathrust and the localized 8–10 m seafloor uplift across a 6–9 km-wide pop-up belt involving up to three pop-ups, is able to reproduce the 2010 tsunami amplitude measured by a DART buoy, and observed run-up heights in the Mentawai Islands. This simple mechanism, observed in analogue sandbox shortening experiments, may thus efficiently generate the oversize waves that characterize Tsunami-Earthquakes. Systematic mapping of pop-ups along accretionary wedge fronts may help identify trench segments prone to produce the special class of seismic events that spawn exceptionally large tsunamis. Published version The Mega-Tera experiment is an international project between the Earth Observatory of Singapore (EOS), the Indonesian Institute of Sciences, Schmidt Ocean Institute (SOI) and the Institut de Physique du Globe de Paris. SOI provided the R/V Falkorfor the experiment and EOS funded the renting of the seismic equipment. The French participation was funded by IPG Paris and INSU-CNRS. This study is also supported by Guangdong Province Introduced In-novative R&D Team of Geological Processes and Natural Disasters around the South China Sea (2016ZT06N331), the National key Research and Development Program of China (2017YFC1500101) and National Natural Science Foundation of China (41976197). We would like to thank the Captain and the team of R/V Falkorfor their help and support during the experiment. We thank B. Be-unaiche, E. Duyck and C. Deplus for discussions and help with backscatter data processing. We thank G. Lamarche for com-ments on an earlier version of the manuscript, as well as two anonymous reviewers and editor J.P. Avouac for their construc-tive comments on this version, and E. Hill for discussions. Raw and processed EM302 (multibeam echo-sounder) data are avail-able at http://www.marine -geo .org /tools /new _search /index .php ?&output _info _all =on &entry _id =FK150523. Seismic reflection data are available upon request. SRTM and GEBCO data were accessed in October 2014 here: http://www2 .jpl .nasa .gov /srtmand http://www.gebco .net. This is Earth Observatory of Singapore publication number 287.

Sumatra subduction zone is one of the most seismically active zones on Earth. After having produced three Mw > 8.4 earthquakes and several Mw > 7.5 earthquakes, including the Mw = 7.8 2010 tsunami earthquake, the northern Mentawai segment is still locked and is capable of generating a great earthquake, possibly a disastrous tsunami. We analyzed ultralong offset seismic reflection data from this locked zone to characterize the nature of the accretionary prism and the plate interface using a combination of traveltime tomography, full waveform inversion, and prestack depth migration. In order to enhance the refractions, we downward extrapolate the streamer data to the seafloor, allowing the refraction arrivals to be observed from near‐zero offset up to far offset, and use a traveltime tomography to determine the background velocity in the upper sediments. Starting from these velocities, we perform a multiscale elastic full waveform inversion to determine the detailed P wave velocity structure of the subsurface. Based on this velocity, we perform a prestack depth migration to obtain seismic image in the depth domain and compute the porosity of the sediments to determine fluid content along faults. Our results show a low‐velocity subduction channel with high porosity at the plate interface that connects the likely active frontal thrusts at the toe of accretionary wedge, suggesting that the frontal section of the prism is seismogenic. We have also observed a low‐velocity layer in the middle of wedge separating old sediments below from new sediments above, defining the roots of bivergent thrust faults up to the seafloor, which can be interpreted as a psudo‐décollement. Published version

The lithosphere–asthenosphere boundary is the most extensive boundary on Earth, separating the mobile plate above from the convecting mantle below, but its nature remains a matter of debate. Using an ultra-deep seismic reflection technique, here we show a systematic seismic image of two deep reflectors that we interpret as the upper and lower limits of the lithosphere–asthenosphere boundary beneath a 40–70-million-year-old oceanic lithosphere in the Atlantic Ocean. These two reflections correspond to 1,260 °C and 1,355 °C isotherms and bound a low-velocity channel, suggesting that the lithosphere–asthenosphere boundary is thermally controlled. We observe a clear age dependency of this sublithospheric channel: its depth increases with age from 72 km where it is 40-Myr-old to 88 km where it is 70-Myr-old, whereas its thickness decreases with age from 18 km to 12 km. We suggest that partial melting, facilitated by water, is the main mechanism responsible for the low-velocity channel. The required water concentration for melting increases with age; nevertheless, its corresponding total mass remains relatively constant, suggesting that most of the volatiles in the oceanic sublithospheric channel originate from a horizontal flux near the ridge axis.

Opium poppy belongs to the family − ‘Papaveraceae’ and is well known mainly for its pharmaceutically important alkaloids and seeds. In order to delineate the gene-effects conditioning the expression of seed yield and straw alkaloids, six crosses viz. IS 14 × Sampada, I 14 × Mtu, Sampada × Sujata, CIM Ajay × Dfr 44, Sapna × Sanchita and SPS 49 × TS 1 involving the eleven parents, were sampled for P1, P2 and F1 (=P1 × P2) non segregating, and F2 (=F1), BCP1 (=F1 × P1), and BCP2 (=F1 × P2) segregating generations. The days to flowering (50%) and plant height showed all the three type of interactions (i, j, l) in three crosses, namely C1 − IS 14 × Sampada and C2 − I 14 × Mtu but the traits peduncle length, codeine and thebaine content showed in other three crosses as C1 − IS 14 × Sampada, C2 − I 14 × Mtu, C3 − Sampada × Sujata and C4 − CIM Ajay × Dfr 44 in order. The two type of interactions additive × additive and additive × dominance interactions (i, j,) exhibited by the C6 − SPS 49 × TS 1 for plant height and thebaine content, C5 − Sapna × Sanchita for peduncle length, codeine and narcotine content. The genetic basis of character expression indicated that the interacting crosses showing non-allelic interactions particularly duplicate epistasis in most of the crosses. While most of those without epistatic interactions exhibited superiority over parental mean. On the basis of study results the two specific cross combinations like Sampada × Sujata and CIMAP Ajay × Dfr 44 are selected to ensure tangible superiority for the most economic traits like high seed yield and poppy straw/capsule husk alkaloids including other contributing traits also like early flowering, capsule index for poppy crop improvement programme.

Propagation of fault rupture to the seafloor is a likely cause of enhanced tsunami generation during megathrust earthquakes. New, high‐resolution seismic reflection profiles and swath bathymetry collected across the northern limit of the Mw 7.8, 25 October 2010 Mentawai tsunami earthquake rupture reveal significant and systematic lateral variations in both the stratigraphic level of the frontal Sunda megathrust and the vergence of its frontal ramp faults. Where ramp faults are uniformly seaward vergent, the décollement resides on top of a strong reflector marking the inferred top of pelagic sediments. Where ramp faults are bivergent (both landward and seaward), the décollement is localized within the subducting clastic sequence, above a xseismically transparent unit inferred to be distal fan muds. Where ramp faults are uniformly landward vergent, the décollement is directly on top of the oceanic crust of the subducting Investigator Fracture Zone. Enhanced surface uplift and tsunamigenesis during the 2010 tsunamigenic earthquake appear to have coincided with propagation of rupture into frontal areas with well‐developed structural bivergence. Frontal bivergence is a geological signal of low basal traction during accrual of slip, and offshore of Sumatra this structural style may mark areas of enhanced tsunami hazard posed by small‐magnitude, shallow megathrust ruptures that propagate into the incoming terrigenous sequence at near‐trench levels. NRF (Natl Research Foundation, S’pore) MOE (Min. of Education, S’pore) Published version

Sweet basil (Ocimum basilicum), a member of the Lamiaceae, is used as an ornamental as well as a culinary herb. It is a rich source of the phenolic compound methyl chavicol and is used as a traditional medicinal plant in India, where the crop is grown on ~2,500 ha annually (4). The species is native to India, where it has been cultivated for >5,000 years. During the rainy season, August of 2013, a severe leaf blight was observed on 30- to 45-day-old sweet basil plants in experimental fields (approximately 5 ha) at the CSIR-CIMAP and adjoining areas in Lucknow. Initial symptoms comprised small, irregular, necrotic lesions that coalesced into a leaf blight. Infected parts of the leaves turned black during wet and humid conditions. The incidence of symptoms ranged from 20 to 30%. Infected leaf samples were cut into small pieces and surface-sterilized with 1% sodium hypochlorite for 1 min, followed by two rinses in sterilized, distilled water. The leaf pieces were then blotted dry with sterilized filter paper, placed onto potato dextrose agar (PDA), and incubated at 28°C for 3 to 5 days. Blackish-brown fungal colonies developed. Microscopic examination revealed the presence of brown conidiophores that were cylindrical, septate, unbranched, and straight or geniculate near the apex. Conidia were three-septate, mostly curved at the third cell from the base, which was usually larger and darker than the other cells; intermediate cells were brown or dark brown; terminal cells were subhyaline or pale brown and 16 to 23.5 × 8.5 to 11.5 μm (the average size of 100 conidia was 19.9 × 10.18 μm). On the basis of these characteristics, the fungus was identified as Cochliobolus lunatus (anamorph Curvularia lunata (Wakk.) Boedijin) (1,2). The identification was confirmed by sequencing the internal spacer (ITS) region of ribosomal DNA (rDNA). Genomic DNA was extracted from five fungal isolates, using the 5 Prime Archive Pure DNA Cell/Tissue kit, and subjected to a polymerase chain reaction (PCR) assay with the universal primers ITS1 and ITS4 (5). The amplified product was cloned and sequenced. An NCBI-BLASTn search showed greatest homology (98% similarity) with the ITS sequence of C. lunatus (GenBank Accession No. DQ836800). The sequence was deposited in Genbank (KM272001). A pathogenicity test was carried out using 10, 30-day-old sweet basil (cv. CIM Soumya) plants in pots, by spraying a spore suspension (105 spores/ml) onto the leaves of each plant. Five plants treated similarly with sterilized, distilled water served as a control treatment. The plants were kept at 27 ± 2°C and 85 ± 3% RH for 8 to 10 days. Small, irregular, necrotic lesions appeared after 4 days on all inoculated leaves, while leaves of control plants remained asymptomatic. Fungi re-isolated from inoculated leaves resembled C. lunatus on the basis of microscopic and sequence data, fulfilling Koch's postulates. The fungus was not re-isolated from the control plants. C. guatemalensis has been reported to cause a leaf spot on sweet basil in Korea (3). To our knowledge, this is the first report of a sweet basil leaf blight caused by C. lunatus in India. C. lunatus has the potential to reduce the yield of sweet basil. References: (1) L. M. Liu et al. Plant Dis. 98:686, 2014. (2) D. S. Manamgoda et al. Fungal Divers. 56:131, 2012. (3) J. H. Park et al. Plant Dis. 96:580, 2012. (4) H. A. A. Taie et al. Not. Bot. Hort. Agrobot. Cluj. Napoca 38:119, 2010. (5) T. J. White et al. Page 315 in: PCR Protocols: A Guide to Methods and Applications. M. A. Innis et al., eds. Academic Press, San Diego, 1990.

Oleo–gum–resin of Boswellia serrata Roxb. (Burseraceae) was collected from Shivpuri forest situated in northwestern district of Madhya Pradesh, India. The commercial samples were purchased from Mandsaur and Neemuch districts (the major herbal markets of Madhya Pradesh) for comparative study of their essential oils. The average essential oil contents in the commercial Neemuch samples (11.1%) were much better as compared to the wild collection from Shivpuri (6.1%) as well as commercial collection from Mandsaur (6.9%). The commercial samples contained higher percentage of monoterpene hydrocarbons (81.9–88.1%) including α-thujene (61.4–69.8%) as the major compound. The wild habitat contained higher percentage of oxygenated monoterpenoids/benzenoids (15.7%) and sesquiterpenes (19.2%) including α-terpineol (7.8%), terpinyl isobutyrate (5.1%), and eudesmol (11.5%). Further, the antimicrobial activities of these collections showed remarkable variation among the essential oils. On the other hand, wild habi...

The genus Withania comprises 23 species, among which only two [W. somnifera (Ashwagandha) and W. coagulans (Ashutoshbooti)] have been reported from India. Withania spp. dried roots are widely used in traditional system of medicine. Optimal germination potential is essential for commercial growers to justify buying premium-priced seed and ensure acceptable performance of their crop. An experiment was initiated to determine seed germination potential and vigor index of W. somnifera and W. coagulans at three constant (15°C, 20°C, and 25°C) and one alternating (15/35°C) temperature (10/14 h) regimes in Petri dishes, with daily 16 h light (180 lx)/8 h dark photoperiod. Highest germination percentage (92%) and seedling vigor index II (0.2583) were observed at 15/35°C, followed by 15°C (90.7% and 0.1207, respectively) in W. somnifera. Vigor index I was highest (344.5) at 15°C, followed by 15/35°C (319.7) in W. somnifera. In the case of W. coagulans, highest germination percentage (65%), seedling vigor in...

The Wharton Basin in the Indian Ocean is one of the most extensively deforming ocean basins, as confirmed by the occurrence of several very large earthquakes starting from January 12, 2012 with Mw 7.2 followed by the great earthquakes of April 11, 2012 with Mw 8.6 and Mw 8.2. Although the Mw 7.2 and Mw 8.2 earthquakes seem to have ruptured the re-activated N–S striking fracture zones, the largest event (Mw 8.6) required the rupturing of several faults, oblique to each other, in a very complex manner. In order to understand the nature of deformation in these earthquakes rupture zones, we recently acquired 90 000 km2 of bathymetry, 11 400 km of sub-bottom profiling, gravity and magnetic data covering the rupture areas of the 2012 earthquakes east of the Ninety-East Ridge, in the northwestern Wharton Basin. These new data reveal six N8°E striking re-activated fracture zones (F5b, F6a, f6b, F7a, F7b and F8), where the fracture zone F6a can be followed for over 400 km and seems to be most active. The epicenters of the Mw 8.6 and Mw 8.2 earthquakes lie on the fracture zones F6a and F7b, respectively. The newly observed fracture F5b in the east is short, and has an extensional basin at its southern tip. The fracture zone F8 defines the eastern boundary of the Ninety-East Ridge. The presence of en echelon faults and pull-apart basins indicate left-lateral motion along these fracture zones. In between these fracture zones, we observe pervasive 290° striking right-lateral shear zones at 4–8 km intervals; one of which has cut through a seamount that might have ruptured during the Mw 8.6 earthquake. We also observe another N20°E striking left-lateral shear zones in the vicinity of F7b and F8, which is coincident with the strike of one of the nodal planes of the Mw 8.6 focal mechanism. These N20°E striking shear zones are interpreted as R Riedel shears and the N290°E striking shear zones as R′ Riedel shears. These shear zones are formed by a series of N335°E striking en echelon normal faults. Our data also show the presence of N65°E striking thrust faults east of the Ninety-East Ridge, orthogonal to the regional principal direction of compression. Furthermore, extensive bending-related faulting is also observed close to the Sumatra trench with normal faults also striking at N335°E, similar to the normal faults that form the shear zones. Normal faults with a similar orientation are also present at the southern tip of F5b. We explain all these observations with a single coherent model of deformation in the Wharton Basin, where a dominant part of the regional NW–SE compressional stress is accommodated along the N8°E re-activated fracture zones, and the rest is distributed along shear zones, thrust and normal faults between these fracture zones. The thrust and normal faults are orthogonal to each other and define the direction of principal compressive and extensive stresses in the region whereas the two shear zone systems form a conjugate pair. NRF (Natl Research Foundation, S’pore) MOE (Min. of Education, S’pore) Published version

Current study aims to explore natural anti-phytopathogenic compounds for plant disease management. Syzygium cumini essential oil and its isolated compounds were screened for their antifungal assay against two phytopathogenic fungi, Rhizoctonia solani AG 4HG-III and Choanephora cucurbitarum . The chemical composition of oil the isolated oil was identified by gas chromatography and gas chromatography/mass spectrometry. Compounds such as 7-hydroxycalamenene, 7-acetoxycalamenene, 1-epi-cubenol, and α-terpineol showed an inhibition, ca. 95%, 80%, 76%, and 82%, respectively, against R . solani whereas 95%, 70%, 92%, and 100% against C . cucurbitarum in contact phase. In addition, high ocimene rich column fractions showed 70% and 87% inhibition against R . solani and C . cucurbitarum , respectively, in volatile phase. The findings of the present study suggest that the isolated 7-hydroxycalamenene, 7-acetoxycalamenene, 1-epi-cubenol, α-terpineol, and ( Z )-β- & ( E )-β-ocimene have a potential to be used as antifungal agents for the effective control of fungal diseases in medicinal plants. We report 7-acetoxycalamenene as novel compound from natural source for first time.

A conjugate system of faults (shear and reactivated fracture zones) accommodates intraplate deformation in the Wharton Basin., The deformation at well-defined, narrow plate boundaries depends on the relative plate motion, but how the deformation takes place within a distributed plate boundary zone remains a conundrum. This was confirmed by the seismological analyses of the 2012 great Wharton Basin earthquakes [moment magnitude (Mw) 8.6], which suggested the rupture of several faults at high angles to one another. Using high-resolution bathymetry and seismic reflection data, we report the discovery of new N294°E-striking shear zones, oblique to the plate fabric. These shear zones are expressed by sets of normal faults striking at N335°E, defining the direction of the principal compressional stress in the region. Also, we have imaged left-lateral strike-slip faults along reactivated N7°E-oriented oceanic fracture zones. The shear zones and the reactivated fracture zones form a conjugate system of faults, which accommodate present-day intraplate deformation in the Wharton Basin.

In the present study, we compared the effects of Al

Fifty land races were collected from Uttar Pradesh, Madhya Pradesh, and Rajasthan in India. 19 genetic stocks were examined for genetic diversity to identify parents for hybridization. Eventually, n2 diallel cross progenies were generated from the five diverse parents. Both additive and non-additive genetic variances were observed. The role of extra-nuclear factors such as cytoplasmic inheritance was very perceptible. The association between heterosis and average divergence was not very distinct. These parents also manifested better combining ability in desirable direction. After field evaluation trials, one recombinant from the heterotic hybrid 1×4 was released as concentrated poppy straw variety CIMAP AJAY in 2011.

Twentyone genotypes of pyrethrum were studied for genetic variability. The highest genotypic and phenotypic coefficient of variations was recorded for cinerin II concentration at 55.53 and 57.27 followed by pyrethrin II at 48.97 and 48.99 lowest for total assay at 25.46 and 28.25, respectively. Six traits showed high heritability 94.01% to 99.90%, the highest being for pyrethrin II (99.90%). Pyrethrin I with total assay and pyrethrin II with jasmolin II were positively associated. Pyrethrin I and II made the highest direct and indirect contribution to total assay, hence may form a good selection criterion for flowers yields and qualitative traits.

A good extent of variation was observed for all the traits among 41 accessions of Ammi visnaga. Morphological variability for stem colour and umbel mutant with centre red to pink was detected. Maximum GCV and high heritability and genetic advance as percentage of mean were observed for biological yield followed by harvest index, seed yield, which may provide good amount of advance expected from selection because these traits may be possibly governed due to additive gene effects. The genotypic correlation in general, was higher than phenotypic; positive significant correlation was observed between seed yield and number of primary branches, harvest index; biological yield and number of umbel, number of primary branches. A high direct positive effect on seed yield was of biological yield followed by harvest index and primary branches. Therefore, composite populations through poly-cross nursery of desired accessions and recurrent selection recommended for genetic improvement in Bishop's weed.

Forty genetic stocks of vetiver (Vetiveria zizanioides L. Nash) were screened for high oil yield. The considerable amount of natural and genetic variability in morpho-metric traits was recorded. The estimate of heritability (^h2BS %) and corresponding genetic advance (GA), both were high for plant height (^h2BS % = 98.48 and GA = 64.83). Genetic (G) and phenotypic (P) associations coefficients among the seven traits indicated that plant height was highly and significantly correlated with tillers/plant (0.399**G, 0.389**P); fresh root with dry root yield (0.905**G, 0.769**P) and oil content with oil yield (0.397**G, 0.390**P) at both genotypic and phenotypic level. The plant height with root length was also positively correlated with each other at both genetic (G) and phenotypic (P) levels (0.282*G, 0.278*P). The path coefficient under study revealed that the highest direct contribution to total oil yield was made by fresh root yield (0.514) followed by oil content (0.386), tillers/plant (0.149) and root length (0.086) in percent.

The purpose of this investigation was to try to understand the antibacterial mechanism of L-(−)-usnic acid isolated for the first time from fruticose lichen Usnea subfloridana using clinical isolates of methicillin-resistant Staphylococcus aureus (MRSA). The minimum inhibitory concentration (MIC) of L-(−)-usnic acid against the clinical isolates of MRSA and reference strain S. aureus MTCC-96 (SA-96) was in the range 25–50 μg/ml. Treatment of both reference and clinical strains (MRSA-ST 2071) with four-fold MIC concentrations (100–200 μg/ml) of L-(−)-usnic acid reduced the viability of cells without damaging the cell wall. However, the loss of 260 nm absorbing material and increase in propidium iodide uptake was observed in both of the strains. Similarly, a combined effect of L-(−)-usnic acid (25–50 μg/ml) and 7.5 % NaCl resulted in a reduced number of viable cells within 24 h in comparison to the control. These observations clearly indicate that L-(−)-usnic acid exerts its action by disruption of the bacterial membrane. Further, in vivo efficacy showed that L-(−)-usnic acid significantly (p < 0.001) lowered the microbial load of spleen at doses ranging from 1 to 5 mg/kg. Further, toxicity studies in infected mice at doses 20 times higher than the efficacious dose indicated L-(−)usnic acid to be safe. Paradoxically, L-(−)usnic acid exhibited changes in serum triglycerides, alkaline phosphatase (ALKP) and liver organ weight in the healthy mice administered with only 25 mg/kg body weight. The results obtained in this study showed that natural L-(−)-usnic acid exerts its antibacterial activity against MRSA by disruption of the cell membrane. Further, the natural L-(−)-usnic acid was found to be safe up to 100 mg/kg body weight, thereby, making it a probable candidate for treating S. aureus infections.

Not uploaded.Key words: M.tuberculosis; Niacin; Nitrate; Catalase; PNBDOI: 10.3126/jnhrc.v5i2.2472Journal of Nepal Health Research Council (JNHRC) Vol. 5, No.2, October 2007 55-61

Effect of Boron on Quality and Yield of Wheat Grains (RR 21)

An unusual pattern of two bottom simulating reflections (BSRs) has been observed on seismic profiles from the continental margin offshore Western Norway. One of these reflections (BSR1) extends over large areas and has the characteristics of the classical BSR, that is a phase-reversed reflection from the base of the gas-hydrate stability zone. The second BSR (BSR0) occurs at approximately 70 ms two-way travel time beneath BSR1 and is here called a double BSR. The distribution of BSR0 is more local than that of BSR1 and it does not show the phase-reversal relative to the sea floor reflection that is characteristic for a BSR at the gas hydrate-free gas boundary. Results from an industrial borehole, from full waveform inversion of multichannel seismic data, from high-frequency ocean bottom hydrophones, and interpretation of seismic profiles, clearly indicate that BSR1 is reflected from the base of the methane hydrate equilibrium field. Results from full waveform inversion indicate that BSR0 corresponds to a 16–20 m zone where the velocity drops from about 1.8 km/s to a minimum of 1.4 km/s and then increases again. The low velocity of 1.4 km/s suggests the presence of free gas. The results support the hypothesis that BSR0 is a reflection from the base of gas hydrates containing hydrocarbons with a heavier molecular weight in addition to methane gas. Interference of reflections from the top and base of the low-velocity zone associated with BSR0 explain why BSR0 is not phase-reversed.

A simple reversed-phase liquid chromatographic method is developed for the simultaneous quantitation of the anticancerous drugs vincristine, vinblastine, and their precursors catharanthine and vindoline using a Merck Chromolith Performance reversed-phase high-performance liquid chromatography column. A better resolution is obtained in comparison with available particulate-type C18 columns. The column provides good reproducibility and peak symmetry. Chromatography is carried isocratically with a mobile phase of acetonitrile-0.1M phosphate buffer containing 0.5% glacial acetic acid (21:79, v/v; pH 3.5) at a flow rate of 1.2 mL/min and UV detection at 254 nm. Parameters such as linearity, limits of quantitation (LOQ) and detection (LOD), precision, accuracy, recovery, and robustness are studied. The method is selective and linear for alkaloid concentration in the range 0.25 microg-25 microg/mL. The LOQ and LOD are 25, 46, 56, and 32 microg/mL and 8, 14, 18, and 10 microg/mL, respectively. The results of accuracy studies are good. Values for coefficient of variation are 2.50, 1.82, 1.33, and 1.13, respectively. The percent recovery of the alkaloids was found to be 96%, 97%, 98%, and 98%, respectively. Peak purity and homogeneity of these compounds in plant extract is studied using a photodiode-array detector. This simple and rapid method of analysis is applied for the determination of these alkaloids in a large number of leaf extracts of Catharanthus roseus..

SUMMARY A tomographic inversion method is presented for the determination of 3-D velocity and interface structure from a wide range of body-wave seismic traveltime data types. It is applicable to refraction, wide-angle reflection, normal-incidence and multichannel seismic data, and is best suited to a combination of these that provides good independent constraints on seismic velocities and interface depths. The inversion process seeks a layer‐interface minimum-structure model that is able to explain the given data satisfactorily by inverting to minimize data misfit and model roughness norms simultaneously. This regularized inversion, and the use of smooth functions to describe velocities and depths, allows the highly non-linear tomographic problem to be approximated as a series of linear steps. The inversion process begins by optimizing the fit to the data of a highly-smoothed initial model. In each subsequent step, structure is allowed to develop in the model with successively greater detail evolving until a satisfactory fit to the data is obtained. Parameter uncertainties for the final model are then estimated using an a posteriori covariance matrix analysis. Smooth layer‐interface models are parametrized using regular grids of velocity and depth nodes from which spline-interpolated interface surfaces and velocity fields are defined. Forward modelling is achieved using ray perturbation theory and a two-point ray tracing method that is optimized for a large number of closely-spaced shot or receiver points. The method may be used to generate 1- and 2-D models (from, for example vertical seismic profile data or 2-D surveys) in which the 3-D geometry of a survey is correctly accounted for. The ability of the method to resolve typical target structures is tested in a synthetic salt dome inversion. From a set of noisy traveltime data, the model converges quickly to a well-resolved final model from different starting models. The application of this method to real data is demonstrated with a combined 3-D inversion of refraction and reflection data which provide P-wave velocity constraints on the methane hydrate stability zone in the Cascadia Margin offshore Vancouver Island.

The essential oil of Melaleuca decora twigs has been obtained by hydrodistillation and analysed by GC-FID, GC/MS and (1)H-, (13)C-NMR experiments. The most abundant class of compounds in M. decora twig oil was phenylpropanoids represented by methyl eugenol (92.4%) as the most exclusive constituent. In terms of molecular diversity, phenylpropanoids dominate M. decora essential oil with low terpenoid (3.9%) proportion.

Summary We present a new method of traveltime tomography. In this method, the traveltime between source and receiver is described by an analytical function, which consists of a series expansion of geometrical coordinates of the source and receiver locations. As the traveltime is derived from the eikonal equation, the analytical function must also satisfy the eikonal equation. This condition imposes a strong constraint on the uniqueness of the analytical function. The coefficients of the series expansion are estimated by minimizing the misfit between the observed and the analytical time function in a least-squares sense. Once the coefficients of the series expansion are known, the eikonal equation, which turns out to also be in the form of a series expansion, provides the velocity in the medium. Thus there are two analytical functions, one defining the traveltime and the other defining the slowness, and they can be used for pre-stack depth migration and velocity model definition. The feasibility of this approach is first tested on a synthetic data set and then applied to a real data set. This new method of tomography and pre-stack migration provides a significant gain in computation time compared with ray-tracing techniques. The method can easily be extended to incorporate reflection data and has potential for solving 3-D seismic reflection and global seismology inverse problems.

The mean time for 50% germination at 20 °C of 12 Indian wheat (Triticum aestivum) cultivars was nearly halved, from 51 h to 27 h, by soaking seed in water for 8 h prior to sowing. A delay of 24 h without further soaking, intended to simulate postponement of sowing, reduced the time saved by priming to 16%. Priming had no effect on final germination percentage. These results were used in the design of 275 on-farm, farmer-managed, participatory trials of seed priming in wheat during the 1997–98 and 1998–99 rabi (post-monsoon) seasons. In forty-one trials in tribal areas of Bihar and West Bengal states of India, seed priming gave a 13% grain yield advantage for farmers growing wheat in marginal areas with low levels of agricultural inputs. Mean benefits from seed priming of wheat in nine trials in Chitwan, Nepal were 17%. In high potential areas of Gujarat, India, 205 trials had higher rates of input use. Yield benefit from priming in these trials averaged only 5% but constituted an extra 200 kg ha−1 grain at little or no cost. In 20 trials on marginal land, with slightly saline irrigation water in Ahmadwala, Pakistan, an average yield increase of 36% was obtained using seed primed with a 0.2% gypsum solution. Collaborating farmers reported that priming wheat seed overnight resulted in faster, more complete emergence, more vigorous early growth, better tillering, earlier flowering, larger ears, earlier maturity and higher yields. In addition, many farmers also reported that foliage in primed plots was a darker shade of green than that in non-primed plots, suggesting that primed plants may have been using nitrogen more efficiently. Seed priming was popular with farmers, most of whom reported that they would prime wheat seed the following year. A survey in Gujarat in 1998–99 of 63 farmers who had tested priming in 1997–98 showed that, while 65% had primed some of their own seed, none had primed more than 50 kg, suggesting that there were practical difficulties in priming larger volumes of seed.

A sensitivity study of elastic parameters in amplitude-variation-with-slowness (AVS) for small- and large-offset seismic data is presented. In order to handle the non-linearity associated with waveform or amplitude beyond the critical slowness, an inversion algorithm based on Bayes' theory is used. A genetic algorithm was used to obtain the a posteriori probability density (PPD) function. The sensitivity analysis is performed on synthetic data containing P-wave as well as converted S-wave reflections. Four different two-layer models, which represent the typical range of AVS responses associated with the gas-sands normally encountered in exploration, were used to examine how well the elastic parameters can be inverted for different parametrizations by comparing the PPD functions. The sensitivity study results suggest that including wide-angle data in the inversion can greatly enhance the quality of inversion. The converted S-wave reflections can provide valuable extra information that can be used to extract elastic parameters. The results with noisy data demonstrate that the contrast of density and three velocity ratios can be estimated robustly with wide-angle reflection data.

Quantifying the melt distribution and crustal structure across ridge-axis discontinuities is essential for understanding the relationship between magmatic, tectonic and petrologic segmentation of mid-ocean-ridge spreading centres. The geometry and continuity of magma bodies beneath features such as overlapping spreading centres can strongly influence the composition of erupted lavas and may give insight into the underlying pattern of mantle flow. Here we present three-dimensional images of seismic reflectivity beneath a mid-ocean ridge to investigate the nature of melt distribution across a ridge-axis discontinuity. Reflectivity slices through the 9 degrees 03' N overlapping spreading centre on East Pacific Rise suggest that it has a robust magma supply, with melt bodies underlying both limbs and ponding of melt beneath large areas of the overlap basin. The geometry of melt distribution beneath this offset is inconsistent with large-scale, crustal redistribution of melt away from centres of upwelling. The complex distribution of melt seems instead to be caused by a combination of vertical melt transport from the underlying mantle and subsequent focusing of melt beneath a magma freezing boundary in the mid-crust.

Seismological studies indicate that the inner core of Earth is anisotropic for compressional waves ( P waves), and has low shear wave ( S wave) velocity, and high seismic attenuation. Using an effective medium theory for composite materials, we show that the presence of a volume fraction of 3 to 10% liquid in the form of oblate spheroidal inclusions aligned in the equatorial plane between iron crystals is sufficient to explain the aforementioned seismic phenomena. Variation of S -wave velocity between the polar axis and equatorial plane is more sensitive to the addition of liquid than that of P waves. The liquid could arise from the presence of dendrites or a mixture of elements other than iron that exist in liquid form under inner-core conditions.

On the northern Cascadia subduction margin, the multichannel seismic amplitude-versus-offset (AVO) behavior of a bottom-simulating reflector (BSR) suggests a P wave velocity change from high-velocity hydrate-bearing sediment to lower velocity sediment containing a small amount of free gas. The observed nonlinear AVO behavior, constant or slightly decreasing amplitudes at near-to-mid offsets and a large-amplitude increase at far offsets, can be reproduced in the models if an S wave velocity enhancement is assumed as expected from hydrate cementation. The AVO behavior of the hydrate BSR is found not to be as useful as was earlier thought for determining the amount of free gas below the BSR. This is because Poisson's ratio change below the BSR due to gas is likely very small in high-porosity unconsolidated sediments. The uncertainty in the models is large, as there is no reliable S wave velocity information for the sediments containing hydrate or gas. AVO modeling alone is not sufficient to distinguish different velocity models across the BSR. Our interpretation of the BSR amplitude behavior is that a P wave velocity increase above the BSR is the main cause of the BSR reflection amplitude increase at large incidence angles. Caution must be taken in applying AVO analysis, as little is known about S wave velocities. However, subtle differences in BSR amplitude behavior and reflection waveform can provide constraints through very careful full waveform inversion. A well-defined reference velocity-depth profile is also required to represent water-saturated sediment unaffected by either hydrate or free gas. Using full waveform velocity inversion, a high-resolution velocity model for the hydrate BSR has been derived. The best fit model for the seismic data near the Ocean Drilling Program (ODP) sites 889/890 consists of a high-velocity zone above the BSR and a thin low-velocity layer below, in agreement with the ODP downhole velocity data.

We have applied full waveform inversion to wide-aperture seismic reflection data from the southern East Pacific Rise near 14°S. The data contain clear compressional wave and doubly converted shear wave arrivals that provide good constraints on the P and S-wave velocities (Vp, Vs, and hence Poisson's ratio σ) and seismic attenuation (Qp, Qs) structure of seismic layer 2. Layer 2A is highly attenuating (Qp = 18–30 and Qs = 8–15) and layer 2B is moderately attenuating (Qp = 30–50 and Qs = 20–25). Our results show high σ at the seafloor and in layer 2A (σ = 0.48). Across the top of the 2A/B transition the rapid increase in Vp is accompanied by a sharp drop in σ to 0.25 within just 200 m of the seafloor. We perform simple calculations to gain an insight into the porosity and crack distribution with depth. These calculations suggest that porosity is in excess of 30% in layer 2A but reduces to 6–7% at the top of the 2A/B transition and to about 5% at a depth of 600 m below seafloor within layer 2B. Our results suggest that there is an increase in the average aspect ratio with depth across the 2A/B transition. The most likely explanation is that numerous thin cracks either mechanically close or are infilled at depth. Our results show there to be an abrupt change in the pore structure across the 2A/B transition which is consistent with a lithologic transition from extrusives to dykes but is equally consistent with a transition (mechanical or hydrothermal) within the extrusive pile.

The determination of along-axis variations in melt properties within the crustal axial magma chamber beneath fast spreading axes is important for understanding melt delivery from the mantle, eruption history along the ridge crest, and the process of crustal accretion. Seismic reflection images1,2,3,4 have shown the molten sill to be continuous along the ridge crest for many tens of kilometres with varying widths (250–4,500?m), but variations in its seismic properties and thickness have remained elusive, despite several attempts to constrain these properties5,6,7. Here we report that the melt sill along the southern East Pacific Rise, which is about 50?m thick, undergoes abrupt changes in its internal properties, ranging from pure melt to mush. The 60-km-long ridge-crest segment near 14°?00′?S is characterized by three 2–4-km sections containing pure melt embedded within a magma chamber rich in mush. These small pure melt pockets may represent a fresh supply of magma from the mantle, capable of erupting and forming the upper crust. Conversely, the 80–90% of the magma chamber which is mushy is unlikely to erupt and may influence the lower-crustal accretion.

Summary Bottom simulating reflectors (BSRs) at the base of the hydrate stability zone are often observed in marine seismic reflection data. The compressional (P-)wave velocity structure of a BSR offshore Costa Rica was analysed by applying a full-waveform inversion technique. The resulting velocity profile indicates that the BSR is caused by a thin low-velocity layer, suggesting the presence of at least a small amount of free gas in the sediment pore space. In undisturbed sediment sections, BSRs offshore Costa Rica are observed over much of the continental margin. They frequently occur at shallow depths beneath the seafloor, usually ~ 100–400 m; at some locations BSRs appear to intersect the seafloor. This was interpreted as an indication that hydrates in the study area form partly from methane which was produced beneath the hydrate stability zone and migrated upwards. In the study area, the vertical movement of the hydrate stability zone relative to a given point in the sediment column, one of the potential factors leading to BSR formation or suppression, is controlled by both sedimentation and vertical tectonism. Both processes may hence play a role in controlling BSR distribution. BSRs are absent in areas which have been affected by slumping, except where the sedimentary section above the BSR remained intact during slumping. This indicates that slope failure can cause the destruction of BSRs.

Four compounds, stigmasterol, stigmasterol-β-D-glucopyranoside, luteolin-7-0-glucopyranoside and dotriacontanoic acid isolated from Vernonia cinerea have shown significant antifeedant activity based on percent feeding-deterrence and effective doses (ED50) against two lepidopterous insects, Spodoptera litura and Spilosoma obliqua. © 1998 John Wiley & Sons, Ltd.

In 1992, British Institutions' Reflection Profiling Syndicate conducted a two-ship coincident near-vertical and wide-angle experiment to determine the detailed velocity structure of the continental crust in the Central North Sea. The results show a near-surface high velocity gradient layer (P-wave velocity reaches 6.0 km/s at ∼5 km depth), a high-velocity zone (6.5 km/s) at 10–15 km depth, a 19-km-thick upper crust and the Moho at a depth of 32–34 km along the 135-km profile. The travel-time and amplitude of wide-angle data require the presence of a dipping reflector originating at the Moho (32 km depth) and continuing down to 38 km in the mantle. The velocity between 19 and 24 km depth is slightly lower (6.1 km/s) than that in the upper crust. The waveform modelling of the combined normal-incidence and wide-angle data requires a number of alternating high- and low-velocity layers in the lower crust (19–33 km). The velocity contrast in the lower part of the lower crust (29–33 km) is large, of the order of 1 km/s (6.5–7.5 km/s). There are a few alternating high- (8.2 km/s) and low-velocity (7.5 km/s) layers in the upper part of the mantle (33–36 km). The high velocity (6.5 km/s) in the upper crust may be due to a high grade of metamorphism, and it may have been formed during the subduction process. The low-velocity (6.1 km/s) in the upper part of the lower crust might be caused by the presence of meta-sediments. The large velocity variations (6.5–7.5 km/s) in the lower part of the lower crust suggest the presence of mafic materials, and may result from under-plating of mafic materials from the mantle. The fractionation of melt can also produce the layering in the upper part of the mantle that is observed from seismic analyses.

In a survey at Lucknow, India, the seedlings of plant species which are prescribed in the Indian traditional system of medicine for a variety of infectious diseases were found to predominate on fresh or decomposing cattle dung, a harsh medium for plant growth due to high microbial load and other abiotic factors. Plants of most of the common species did not occur on the cattle dung heaps. It was hypothesized that plant species which are able to grow on cattle dung may have antimicrobial compounds in their seeds to protect them from microbial attack. In confirmation, the seeds of 15 of the coprophilous (kopros--dung, philein--to love) plant species, identified as occurring most frequently on fresh/decomposing cattle dung were directly tested against eight bacterial and three fungal strains. Interestingly, seeds of all the examined species exhibited antimicrobial activity. The seeds of the species found more frequently on the cattle dung heaps possessed higher levels of antimicrobial activities.

We have applied waveform inversion to multichannel seismic reflection data collected at the East Pacific Rise at 9°40'N in order to determine the precise velocity structure of the magma body causing the axial magma chamber reflection. Our analysis supports the idea of a molten sill as previously suggested from forward modeling of seismic data from this location. Our inverted solution has a 30-m-thick sill with a P wave seismic velocity of 2.6 km s -1 . Although not well constrained by the data we believe that the S wave velocity in the sill is not significantly different from 0.0 km s -1 . The low P- and S- wave velocities in the sill imply that it contains less than 30% crystals. The molten sill is underlain by a velocity gradient in which the P wave velocity increases from 2.6 to 3.5 km s -1 over a vertical distance of 50-m. The shape of our velocity-depth profile implies that accretion of material to the roof of the sill is minor compared to accretion to the floor. The underlying velocity gradient zone may represent crystal settling under gravity. We suggest that only material from the 30-m-thick layer can erupt.

Migration velocity analysis, a method for determining long wavelength velocity structure, is a critical step in prestack imaging. Solution of this inverse problem is made difficult by a multimodal objective function; a parameter space often vast in extent; and an evaluation procedure for candidate solutions, involving the calculation of depth-migrated image gathers, that can be prohibitively expensive. Recognizing the global nature of the problem, we employ a genetic algorithm (GA) in the search for the optimum velocity model. In order to describe a model efficiently, regions of smooth variation are identified and sparsely parametrized. Region boundaries are obtained via map migration of events picked on the zero-offset time section. Within a region, which may contain several reflectors, separate components describe long and short wavelength variations, eliminating from the parameter space, models with large velocity fluctuations. Vital to the success of the method is rapid model evaluation, achieved by generating image gathers only in the neighbourhood of specific reflectors. Probability of a model, which we seek to maximize, is derived from the flatness of imaged events. Except for an initial interpretation of the zero-offset time section, our method is automatic in that it requires no picking of residual moveout on migrated gathers. Using an example data set from the North Sea, we show that it is feasible to solve for all velocity parameters in the model simultaneously: the method is global in this respect also.

The essential oil composition of Murraya exotica leaves and flowers from CIMAP Research Farm, Lucknow, were analysed by GC and GC-MS, which resulted in the identification of 56 and 72 constituents, representing 99.8% and 99.2% of the oils, respectively. The leaf oil showed ( £ )-nerolidol (27.8%), α-zingiberene (10.0%), β-caryophyllene (9.7%), (E,E) farnesol (8.9%) and δ-elemene (5.1%) as the major constituents, while the flower oil showed (E,E,E)-α-springene (23.8%), ( £ )-nerolidol (18.7%), (E,E) α-farnesene (13.2%), methyl palmitate (6.8%) and germacrene B (5.9%) as the major constituents.

In this work, cultivated Pimenta racemosa from North Indian plains was studied for its leaf volatile composition twice in year at two distinct seasons (spring and autumn) using GC-FID, enantio-GC-FID, GC/MS and 1H-, 13C-NMR and DEPT experiments. Phenylpropanoid was the abundant class of compounds represented by eugenol (72.9%) followed by chavicol (7.7%) whereas myrcene (9.6%) and limonene (3.8%) were identified as the most exclusive terpene constituents in spring collection. The autumn sample was recorded with highest eugenol (92.9%) proportion. Notably, presence of chavicol differentiates this oil from Pimenta dioica. An enantiomeric excess for (S)-(-)-limonene (41.1-45.3%) and (R)-(-)-linalool (86.7-89.9%) was recorded over (R)-(+)-limonene and (S)-(+)-linalool, respectively when separated on 6-tert-butyldimethylsilyl-2,3-diethyl-β-cyclodextrin chiral phase. Moreover, both the monoterpene derivatives occur as enantiomeric mixture in P. racemosa leaf essential oil.