2,520 research outputs found
Formation of caustics in Dirac-Born-Infeld type scalar field systems
We investigate the formation of caustics in Dirac-Born-Infeld type scalar
field systems for generic classes of potentials, viz., massive rolling scalar
with potential, and inverse
power-law potentials with . We find that in the case
of\texttt{} exponentially decreasing rolling massive scalar field potential,
there are multi-valued regions and regions of likely to be caustics in the
field configuration. However there are no caustics in the case of exponentially
increasing potential. We show that the formation of caustics is inevitable for
the inverse power-law potentials under consideration in Minkowski space time
whereas caustics do not form in this case in the FRW universe.Comment: 16 pages, 14 figures, major revision, conclusions strengthen, to
appear in PR
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Educational neuroscience: Neural structure-mapping and the promise of oscillations
A critical goal for educational neuroscience is to specify causal developmental mechanisms of learning. In-depth understanding of neural information coding and transmission should enable understanding of how sensory systems build the cognitive systems critical for education–language, attention, memory-over developmental time. Cortical oscillatory encoding processes may offer mechanistic insights into how developmental trajectories unfold. All educators are familiar with children who show mastery of taught information one week, yet subsequently appear to lose it. Oscillatory research shows that sensory information that arrives out of phase with ongoing oscillations does not reach awareness, while complex combinations of bottom-up and top-down phase-phase and phase-power relations enable context and prior knowledge to influence current performance. Oscillatory studies of language are used to illustrate the promise of oscillations research for education.MRC (G0902375)This is the author accepted manuscript. The final version is available from Elsevier via http://dx.doi.org/10.1016/j.cobeha.2016.05.011
Tidal and diel influence on zooplankton occurrence in the Mandovi estuary, Goa
Distribution and abundance of zooplankton over the tidal cycle were studied in the Mandovi estuary, Goa, during August and December 1971 and May 1972. Tide induced salinity fluctuations were obvious with high values during spring tides. Salinity was low during August, apparently due to precipitation and land run off but increased subsequently. The mean biomass values for the day and night collections were 13.6 and 19.8 ml/100 m super(3) respectively. Occurrence of most of the zooplankton taxa and species was related to diel rhythm and tidal oscillations. However, overall mean zooplankton standing stock at both the stations were same (16.3 ml/100 m super(3)) indicating that estuarine zooplankton maintained their position during tidal exchanges. Variations in occurrence of common groups and species of zooplankton over the tidal cycle are discussed
Socio-economic dimension of fish farming in Assam
Information on socio-economic framework of the fish farmer
community forms a benchmark for policy formulation to develop this
economically backward sector. Very few studies have been conducted on the
socio-economic aspect of fish farming. Two districts of Assam, Darrang and
Nagaon, were selected for this study where 120 respondents from each district
were selected randomly. The characteristics representing the personnel and
socio-economic attributes of the fish farmers are presented in this paper. The
socio-economic status of fish farmers has to be improved by bringing the
modern concepts of fish farming to the doorstep of farmers
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