Flow patterns around old sunspots and flare activity

New magnetic flux emerges significantly more probably in already existing solar active regions. Based on the the Debrecen Observatory photographic observations, several active regions are collected, where at least one large, X-class flare was recorded, and emergence of new activity, birth and quick motion of new umbrae was observed in the vicinity of old spots, the new activity emerged in the center of the old active region. Newly emerging magnetic flux in older sunspot groups can be distinguished by its quicker and generally westward proper motions. Umbrae of the new activity do not coalesce with older umbrae of the same polarity, but both elastic and inelastic collisions between them can be observed. Spots of the emerging new activity can flow around old unipolar spots (presumably shallower structures, “ω-loops”) westward, like a hydrodynamic flow around a cylinder, forming a wake behind it. Collision of different polarities in the wake can lead to large flares. The presence of old spots disturbs the normal emergence of the new activity, so motions of the new spots are distorted by the flow, the new emerging “Ω-loop” can be stuck between the umbrae of the old, tight dipole, the orientation of the new dipole can be distorted by as much as 180◦. The general direction of the flow around the old spots seems to depend on the latitude, the angle between the motion axis and the E-W direction grows with the latitude. The intensive flare activity seems to be connected strongly with the newly emerging magnetic flux; interacting of differently oriented dipoles and the difference of the orientation of the emerging new dipole from the ordinary Hale-Nicholson orientation is also significant. Simply large gradients of magnetic fields (δ-configuration) are not enough, dynamical processes (emergence of new flux, shearing or colliding motions of umbrae of different magnetic polarity) must also be present for large flares

A version of Tutte's polynomial for hypergraphs

Tutte's dichromate T(x,y) is a well known graph invariant. Using the original definition in terms of internal and external activities as our point of departure, we generalize the valuations T(x,1) and T(1,y) to hypergraphs. In the definition, we associate activities to hypertrees, which are generalizations of the indicator function of the edge set of a spanning tree. We prove that hypertrees form a lattice polytope which is the set of bases in a polymatroid. In fact, we extend our invariants to integer polymatroids as well. We also examine hypergraphs that can be represented by planar bipartite graphs, write their hypertree polytopes in the form of a determinant, and prove a duality property that leads to an extension of Tutte's Tree Trinity Theorem.Comment: 49 page

Goussia trichogasteri n. sp. (Apicomplexa: Eimenidae) infecting the aquarium-cultured golden gourami Trichogaster trichopterus trichopterus

Goussia trichogasteri n. sp. is described from the gut of the aquarium fish Trichogaster trichopterus trichopterus. Gamogonic stages develop epicellularly in the gut epithelium. Oocysts are shed in early stage of sporulation. Sporulated oocysts are characterised by having centrally locating oocyst residua. The whole development of the species takes place in the aquarium