Hydra feeding response is a very primitive olfactory-like behavior present in a multicellular organism. We investigated the role of nitric oxide (NO) in the induction and control of hydra feeding response. Under basal conditions, hydra specimens produce detectable amounts of nitrite (NO2-), the breakdown product of NO. When hydra were incubated with reduced glutathione (GSH), the typical activa...

Hydra can be obtained from either of the following websites; Hydra is an adaptive particle-particle, particle-mesh plus smoothed particle hydro-dynamics N-body simulation program. It can be used with either periodic or isolated boundary conditions. A compiler flag allows the gas calculation to be turned off, converting Hydra to a collisionless mode. An installation guide comes with the release ...

For the first time effects of norflurazon on green (Hydra viridissima Pallas, 1766) and brown hydra (Hydra oligactis Pallas, 1766) in high- and low-light conditions were investigated in order to establish the extent of damage that this substance inflicts, with special emphasis on the "bleaching effect" and the effect on hydra-algae symbiosis. Green hydra is a typical example of an endosymbiotic...

Abstract We introduce L-hydra (landmarked hyperbolic distance recovery and approximation), a method for embedding network- or distance-based data into space, which requires only the measurements to few ‘landmark nodes’. This landmark heuristic makes applicable large-scale graphs improves upon previously introduced methods. As mathematical justification, we show that point configuration in $d$-d...

HYDRA simulates a variety of experiments carried out at the National Ignition Facility and other high energy density physics facilities. It has packages to simulate radiation transfer, atomic physics, hydrodynamics, laser propagation, and a number of other physics effects. HYDRA has over one million lines of code, includes MPI and thread-level (OpenMP and pthreads) parallelism, has run on a var...

In 1909, several years before the famous `Organizer' experiments of Spemann and Mangold, Ethel Browne demonstrated induction of a secondary axis in hydra by grafting a hypostome. Based on this and subsequent work, in the late sixties, Lewis Wolpert proposed the theory of morphogen gradients and positional information. We have studied secondary axis induction by hypostome and foot tissue using t...

Hydra is among the most primitive organisms possessing a nervous system and chemosensation for detecting reduced glutathione (GSH) for capturing the prey. The movement of prey organisms causes mechanosensory discharge of the stinging cells called nematocysts from hydra, which are inserted into the prey. The feeding response in hydra, which includes curling of the tentacles to bring the prey tow...

Symbiotic associations are of broad significance in evolution and biodiversity. Green Hydra is a classic example of endosymbiosis. In its gastrodermal myoepithelial cells it harbors endosymbiotic unicellular green algae, most commonly from the genus Chlorella. We reconstructed the phylogeny of cultured algal endosymbionts isolated and maintained in laboratory conditions for years from green Hyd...

In Hydra four high performance processors communicate via a shared secondary cache. The shared cache is implemented using multichip module (MCM) packaging technology. The Hydra multiprocessor is designed to efficiently support automatically parallelized programs that have high degrees of fine grained sharing. This paper motivates the Hydra multiprocessor design by reviewing current trends in ar...

Stable endosymbiosis depends upon balanced growth of the symbionts. In green hydra, coincident patterns of host and algal mitotic index suggest that coordinated reproduction provides for balanced growth. However, when hydra shrink during food shortage, the population of endosymbiotic algae in a green hydra must likewise decline in size. Thus far, no mechanism of reducing the size of the endosym...