We extend the excluded Kn minor theorem of Robertson and Seymour to infinite graphs, and deduce a structural characterization of the infinite graphs that have no Kא0 minor. The latter is a refinement of an earlier characterization of Robertson, Seymour and the second author.

A faunal overview is presented of the molluscan families Amphibulimidae, Megaspiridae, Odontostomidae, Orthalicidae, Simpulopsidae in Bolivia, Ecuador, and Peru. These Central Andean countries are known for their biodiverse malacofauna, of which the superfamily Orthalicoidea takes relatively a large share. In this paper the five families containing 103 (sub)species, for which systematic informa...

Variational integrals containing several functions of one independent variable subjected moreover to an underdetermined system of ordinary differential equations (the Lagrange problem) are investigated within a survey of examples. More systematical discussion of two crucial examples from Part I with help of the methods of Parts II and III is performed not excluding certain instructive subcases ...

the authors describe two interesting and seldom cases of atrophia gyrata j and believe it to be a congenital hereditary disease with a recessive character. like retinitis pigmentosa, it does not affect the central posterior parts of the retina but the lesions are around the periphery. the visual fields are narrowed. they discuss; the similarity of this disease with atrophia gyrata described by ...

introduction more than 90% of drinking water in cities around the world and about 40% of the agricultural water supply from groundwater resources.,thus, groundwater quality consideration issue is inevitable . one of the most important parameter which can show the quality of drinking water is nitrate concentration. nitrate enters the groundwater and surface water through the decomposition of hum...