10 research outputs found
FractalAnalyzer: A MATLAB Application for Multifractal Seismicity Analysis
No full textEarthquakes are seismic phenomena caused by the sudden release of energy in the Earth’s crust. Their effects range from ground shaking to faulting. Geological and geophysical studies, especially in light of plate tectonic theory have been used to explain the occurrence of earthquakes. Thus from the point of view of statistical fractals, earthquakes cannot be interpreted as random independent events (i.e., having Poisson distribution). Rather, it is observed that the events of the same sequence are clustered in time and space (Shlien and Toksoz, 1970; Vere?Jones, 1970; Smalley et al., 1987; De Natale et al., 1988; Roy and Mondal, 2012a,b).Precision and Microsystems EngineeringMechanical, Maritime and Materials Engineerin
Monitoring the strata behavior in the Destressed Zone of a shallow Indian longwall panel with hard sandstone cover using Mine-Microseismicity and Borehole Televiewer data
No full textHimalayan hazard study on the basis of stress and strain state of 1991 Uttarkashi earthquake using Coulomb stress transfer model
No full textUttarkashi region of Himalaya was struck by a destructive earthquake (Mw = 6.8) on 19 October 1991 with its epicentre located at 30.78°N latitude and 78.77°E longitude. Here, we use Coulomb stress model for the study of this major event. Coulomb 3.1 application is used to generate the earthquake model and develop the stress change maps of the region. The 1991 Uttarkashi earthquake and succeeding earthquakes of Mb > 3.5 are used for the study. One of the motives of this work is to correlate the main shock and the successive minor earthquakes that have occurred in the region. Further, we have studied the 1999 Chamoli earthquake using this model and attempted to relate its occurrence with the Uttarkashi earthquake based on propagation of strain energy. The study of Uttarkashi 1991 earthquake by this method supports the main shock and its controlling effect on the later earthquakes’ observations in the nearby region with the view that many zones of such shock can occur in the future. This model is also used to predict the direction of propagation of strain energy, thereby locating the region that will be affected by the future shocks
Prognosticating buried potential mineral deposits in virgin areas of Odisha and adjoining regions, India, using 3D Euler’s deconvolution technique on gravity data for detailed exploration in future
No full textIntegration of Production Logging and Digital Entry Fluid Imaging Tool in Bombay Offshore
No full textOn the fractional solubility of copper in marine aerosols : toxicity of aeolian copper revisited
No full textAuthor Posting. © American Geophysical Union, 2010. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Geophysical Research Letters 37 (2010): L20601, doi:10.1029/2010GL044817.Paytan et al. (2009) argue that the atmospheric deposition of aerosols lead to copper concentrations that are potentially toxic to marine phytoplankton in a large area of tropical and subtropical North Atlantic Ocean. A key assumption in their model is that all marine aerosols (mineral dust and anthropogenic particles) have a high (40%) fractional solubility of copper. Our data show that the fractional solubility of copper for Saharan dust over the Sargasso Sea and Bermuda is significantly lower (1–7%). In contrast, anthropogenic aerosols with non-Saharan sources have significantly higher values (10–100%). Hence, the potential Cu toxicity in the tropical and subtropical North Atlantic should be re-estimated, given the low fractional solubility of Cu in the Saharan dust that dominates aerosol deposition to this region.This research was supported by U.S.
National Science Foundation (Chemical Oceanography) grants OCE‐
549954 (E.R.S), OCE‐0222053 and OCE‐0550594 (P.N.S) and OCE‐
0222046 and OCE‐0550592 (T.M.C)
Temporal progression of photosynthetic-strategy in phytoplankton in the Ross Sea, Antarctica
No full textAuthor Posting. © The Author(s), 2015. This is the author's version of the work. It is posted here for personal use, not for redistribution. The definitive version was published in Journal of Marine Systems 166 (2017): 87-96, doi:10.1016/j.jmarsys.2016.08.014.The bioavailability of iron influences the distribution, biomass and productivity of
phytoplankton in the Ross Sea, one of the most productive regions in the Southern
Ocean. We mapped the spatial and temporal extent and severity of iron-limitation of
the native phytoplankton assemblage using long- (>24 h) and short-term (24 h) iron-
addition experiments along with physiological and molecular characterisations during
a cruise to the Ross Sea in December-February 2012. Phytoplankton increased their
photosynthetic efficiency in response to iron addition, suggesting proximal iron
limitation throughout most of the Ross Sea during summer. Molecular and
physiological data further indicate that as nitrate is removed from the surface ocean the
phytoplankton community transitions to one displaying an iron-efficient photosynthetic
strategy characterised by an increase in the size of photosystem II (PSII) photochemical
cross section (σPSII) and a decrease in the chlorophyll-normalised PSII abundance.
These results suggest that phytoplankton with the ability to reduce their photosynthetic
iron requirements are selected as the growing season progresses, which may drive the
well-documented progression from Phaeocystis antarctica- assemblages to diatom-dominated phytoplankton. Such a shift in the assemblage-level photosynthetic strategy
potentially mediates further drawdown of nitrate following the development of iron
deficient conditions in the Ross Sea.This research was supported by grants from the National
Science Foundation (ANT-0944254 to W.O.S., ANT-0944174 to P.N.S.), and a NERC
PhD studentship to TRK
Controls on dissolved cobalt in surface waters of the Sargasso Sea : comparisons with iron and aluminum
No full textAuthor Posting. © American Geophysical Union, 2012. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Global Biogeochemical Cycles 26 (2012): GB2020, doi:10.1029/2011GB004155.Dissolved cobalt (dCo), iron (dFe) and aluminum (dAl) were determined in water
column samples along a meridional transect (~31°N to 24°N) south of Bermuda in
June 2008. A general north-to-south increase in surface concentrations of dFe (0.3–1.6 nM) and dAl (14–42 nM) was observed, suggesting that aerosol deposition is a significant source of dFe and dAl, whereas no clear trend was observed for near-surface dCo concentrations. Shipboard aerosol samples indicate fractional solubility values of 8–100% for aerosol Co, which are significantly higher than corresponding estimates of the solubility of aerosol Fe (0.44–45%). Hydrographic observations and analysis of time series rain samples from Bermuda indicate that wet deposition accounts for most (>80%) of the total aeolian flux of Co, and hence a significant proportion of the atmospheric input of dCo to our study region. Our aerosol data imply that the atmospheric input of dCo to the Sargasso Sea is modest, although this flux may be more significant in late summer. The water column dCo profiles reveal a vertical distribution that predominantly reflects ‘nutrient-type’ behavior, versus scavenged-type behavior for dAl, and a hybrid of nutrient- and scavenged-type behavior for dFe. Mesoscale eddies also appear to impact on the vertical distribution of dCo. The effects of biological removal of dCo from the upper water column were apparent as pronounced sub-surface minima (21 ± 4 pM dCo), coincident with maxima in Prochlorococcus abundance. These observations imply that Prochlorococcus plays a major role in removing dCo from the euphotic zone, and that the availability of dCo may regulate Prochlorococcus growth in the Sargasso Sea.This study
was supported by a University of Plymouth, Marine Institute scholarship to
R.U.S., a U.S. National Science Foundation grant to P.N.S. (OCE-0550594),
T.M.C. (OCE-0550592) and E.R.S. (OCE-0549954), and a European Commission
Marie Curie Outgoing International Fellowship under contract
PIOF-GA-2009-235418 SOLAIROS for S.J.U.2012-11-1
Verbal aggression, physical aggression and inappropriate sexual behaviour following brain injury
No full textTwo critical issues concerning serious disorders of interpersonal behaviour following brain injury were investigated over four studies. For the first time, verbal aggression, physical aggression and inappropriate sexual behaviour were shown to be better conceptualised as distinct forms of disordered behaviour, rather than reflecting a single dimension of behavioural dyscontrol. Study 1 demonstrated the psychometric reliability and validity of the BIRT Aggression Rating Scale (BARS) – a new observational tool with which to systematically and contemporaneously record aggressive behaviours. Study 2 used data from the BARS and measures of inappropriate sexual behaviour exhibited by 152 participants with brain injury undergoing residential neurobehavioural rehabilitation. Principal component analysis revealed a clear separation between aggression and inappropriate sexual behaviour. Furthermore, a distinction between verbal and physical aggression was also justified. These results were replicated in study 3 using observed behavioural recordings on the BARS and the St Andrew’s Sexual Behaviour Assessment (SASBA) in a separate larger sample. It is recommended that these distinctions be reflected in future research.
The second critical issue was addressed across the four studies and concerned the neurocognitive correlates of each type of behaviour. Males showed an increased risk for all three behaviours, while poorer verbal skills, impaired self-awareness and poorer social participation were consistently associated with both types of aggression only. Other measures of neurocognitive function and emotional status were not significant predictors within multivariate analyses. Study 4 addressed potential links to executive function in a subsample of 86 participants. Excessive rule violations on the D-KEFS Tower Test were associated with the presence of verbal aggression and inappropriate sexual behaviour. Scores on the D-KEFS Verbal Fluency Test had an unexpectedly positive relationship with the presence of all three behavioural conditions, perhaps indicating the importance of behavioural drive. The implications for clinical work and further research are discussed
