25 research outputs found
Workers of the primitively eusocial wasp Ropalidia marginata do not perceive their queen across a wire mesh partition
Queens of primitively eusocial wasps generally have active and behaviourally dominant queens who use physical aggression to suppress worker reproduction. Although a Ropalidia marginata queen is strikingly docile and behaviourally non-dominant, she is completely successful in maintaining reproductive monopoly. R. marginata queens must achieve such reproductive monopoly by some means other than overt physical aggression. Upon loss or removal of the queen, one of the workers (referred to as the potential queen) becomes extremely aggressive and will eventually go on to become the next queen of the colony, if the original queen is not returned. The fact that potential queens are not discernible in the presence of the queen but become obvious within minutes after removal of the queen raises the question of how workers in general and the potential queens in particular, perceive the presence or absence of their queens. Here, we have conducted experiments in which we separate half of the workers from their queen by a wire mesh screen and study their behavioural response to such separation. We demonstrate that the presence of the queen is not perceived across the wire mesh screen, which suggests that if the queen uses a pheromone to signal her presence, then that pheromone is not very volatile
Classical Electron Model with Negative Energy Density in Einstein-Cartan Theory of Gravitation
Experimental result regarding the maximum limit of the radius of the electron
\sim 10^{-16} cm and a few of the theoretical works suggest that the
gravitational mass which is a priori a positive quantity in Newtonian mechanics
may become negative in general theory of relativity. It is argued that such a
negative gravitational mass and hence negative energy density also can be
obtained with a better physical interpretation in the framework of
Einstein-Cartan theory.Comment: 12 Latex pages, added refs and conclusion
Relativistic Electromagnetic Mass Models: Charged Dust Distribution in Higher Dimensions
Electromagnetic mass models are proved to exist in higher dimensional theory
of general relativity corresponding to charged dust distribution. Along with
the general proof a specific example is also sited as a supporting candidate.Comment: Latex, 7 pages. Accepted in Astrophysics and Space Scienc
Relativistic anisotropic charged fluid spheres with varying cosmological constant
Static spherically symmetric anisotropic source has been studied for the
Einstein-Maxwell field equations assuming the erstwhile cosmological constant to be a space-variable scalar, viz., . Two
cases have been examined out of which one reduces to isotropic sphere. The
solutions thus obtained are shown to be electromagnetic in origin as a
particular case. It is also shown that the generally used pure charge
condition, viz., is not always required for constructing
electromagnetic mass models.Comment: 15 pages, 3 eps figure