4,594 research outputs found
Moderating Urbanization and Managing Growth: How Can Colombo Prevent the Emerging Chaos?
This paper examines urbanization trends, the growth of Colombo and its present state of development. It looks at the approaches to the planned interventions in the city and demonstrates how a uni-directional urban development has had a detrimental impactColombo, urban development, managing urbanization, planning, housing,
Light transmission through and its complete stoppage in an ultra slow wave optical medium
Light Wave transmission -- its compression, amplification, and the optical
energy storage -- in an Ultra Slow Wave Medium (USWM) is studied analytically.
Our phenomenological treatment is based entirely on the continuity equation for
the optical energy flux, and the well known distribution-product property of
Dirac delta-function. The results so obtained provide a clear understanding of
some recent experiments on light transmission and its complete stoppage in an
USWM.
Keywords : Ultra slow light, stopped light, slow wave medium, EIT.Comment: (single-column 5pages PDF). Simple class-room phenomenological model
of stopped light. Comments most welcom
Collective force generated by multiple biofilaments can exceed the sum of forces due to individual ones
Collective dynamics and force generation by cytoskeletal filaments are
crucial in many cellular processes. Investigating growth dynamics of a bundle
of N independent cytoskeletal filaments pushing against a wall, we show that
chemical switching (ATP/GTP hydrolysis) leads to a collective phenomenon that
is currently unknown. Obtaining force-velocity relations for different models
that capture chemical switching, we show, analytically and numerically, that
the collective stall force of N filaments is greater than N times the stall
force of a single filament. Employing an exactly solvable toy model, we
analytically prove the above result for N=2. We, further, numerically show the
existence of this collective phenomenon, for N>=2, in realistic models (with
random and sequential hydrolysis) that simulate actin and microtubule bundle
growth. We make quantitative predictions for the excess forces, and argue that
this collective effect is related to the non-equilibrium nature of chemical
switching.Comment: New J. Phys., 201
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