Dynamical simplices and Fra\"iss\'e theory

We simplify a criterion (due to Ibarluc\'ia and the author) which characterizes dynamical simplices, that is, sets $K$ of probability measures on a Cantor space $X$ for which there exists a minimal homeomorphism of $X$ whose set of invariant measures coincides with $K$. We then point out that this criterion is related to Fra\"iss\'e theory, and use that connection to provide a new proof of Downarowicz' theorem stating that any Choquet simplex is affinely homeomorphic to a dynamical simplex. The construction enables us to prove that there exist minimal homeomorphisms of a Cantor space which are speedup equivalent but not orbit equivalent, answering a question of D. Ash

Evidence of a naturally occurring inhibitor possibly limiting Dermocystidium marinum in Virginia

Dermocystidium marinum, a fungus parasite common in oysters on the eastern shore of Chesapeake Bay, suddenly dissapeared at the beginning of the marsh and bay system of\u27 the outer Virginia coast. No D. marinum was found on the outer coast (Seaside) although temperatures and salinities seem to be optimal. Introduction of populations of infected oysters seem to lose the dieease, but individuals do not. What seems to be a water derived inhibitor was found in a few water samples collected at Wachapreague on the Seaside. Comparable inhibition was not found in Chesapeake Bay water. The inhibitor is difficult to demonstrate and its nature is uncertain. It is suggested that the inhibitor may keep the disease from invading Virginia\u27s outer bays

Winter mortalities of oysters on the Eastern Shore of Virginia, 1959-1961

During the winter of 1960-61 exceptional mortalities occurred among certain oysters on the Virginia Seaside. These mortalities were greatest among James River oysters held intertidally and South Carolina imports placed below low tide level. Intertidal native oysters suffered small mortalities but among subtidal native or James River oysters only the very oldest, with extensive disease histories, showed any winter mortality. (...

Studies on oyster scavengers and their relation to the fungus Dermocystidium marinum

Dermocystidium marinum, a parasitic fungus of oysters, was demonstrated from the stomach of the snail, Urosalpinx cinerea, from the stomach, intestine, and body of three fishes, Gobiosoma bosci, Chasmodes bosquianus, and Opsanus tau, and from the body, especially setae, of two crabs, Neopanope texana and Rhithropanopeus harrisii. All animals containing D. marinum had scavenged oysters infected by the fungus. A few oysters became lightly infected when kept in aquaria with fishes that ·had been fed infected oyster tissue. In one tidal inlet of Chesapeake Bay, Virginia, Eurypanopeus depressus was the most abundant scavenger, followed by Nassarius vibex, Gobiosoma bosci, and Panopeus herbstii. Killed oysters on this reef were consumed by scavengers in less tiian one day in temperatures over 24 C. At temperatures above 18 C, dead oyster tissue never remained long enough to decay. Theoretical methods of transmission of D. marinum by scavengers are discussed. It is concluded that nearly aIl dying oysters are consumed by animals during periods of normal mortality, so their parasites must pass through the digestive systems of scavengers

Studies on oyster scavengers and their relation to the fungus disease Dermocystidium marinum

Within the past decade there have been several studies on the biological structure of oyster reefs. These studies, however, gave few insights into the dynamics of oyster communities. The extensive studies of Hedgpeth (1953) , Gunter (1955), and Parker (1955, 1969) in Texas and Korringa (1951) in Holland were largely concerned with sessile forms, and the highly motile fishes went almost unnoticed. While these studies clearly emphasized imrmotile organisms, the present study leans in the opposite direction. This study started from casual observations of oyster fishes, and progressed to comparisons of mortality of oysters with activity of other members in the community

Studies on the Mud Crabs (Xanthidae) of the Eastern Shore of Virginia

Small xanthid crabs are among the most abundant members of estuarine communities, and doubtless they have important influence in several communities. In Chesapeake Bay and environs mud crabs are one of the most conspicious members of the oyster community, and they must comprise a large biomass, despite their small size. Collections and observations were made at 11 localities visited at least once a month on the Eastern Shore of Virginia from August 1959 through November 1960, with some scattered study until August 1961

Checklist of fishes of Area M-3

Monthly fish collections were made with seines, nets, trawls, etc. at various stations throughout East Bay, West Bay, and lower Galveston Bay (Area M-3), Texas. Associated data on hydrography and other environmental parameters were also recorded. These data serve to document the occurrence, relative abundance, and life history of fish species in the study area, as well as their relationship to hydrography

Ecological studies related to pollution

Hydrological parameters were recorded from stations in the Texas City Ship Channel and the Offatts Bayou region of the Galveston Bay System. Miscellaneous ecological data on the fish populations and other marine life in the area were also collected. These baseline data were used for ecological comparisons with other unpolluted areas

ideal typical process of competition and customer analysis on the example of the events offered in Lutherstadt Wittenberg

Die vorliegende Bachelorarbeit wurde in dem Fachbereich Wirtschaftswissen-schaften zu dem Thema „Idealtypischer Prozess einer Konkurrenz- und Kunden-analyse am Beispiel der Veranstaltungsangebote in Lutherstadt Wittenberg“ ge-schrieben. Die Arbeit ist so konzipiert, dass der Leser sowohl einen Überblick über die wissenschaftliche, als auch von der praktischen Seite bekommt. Daneben kann die Arbeit dazu dienen, die Aussagekraft von Marktforschungsuntersuchun-gen kritisch zu betrachten, sowie die Leistungsfähigkeit der Unternehmen, welche Veranstaltungsangebote für das Freizeit- und Gesellschaftsbedürfnis anbieten, kennen zu lernen. Für die Durchführung eigener Untersuchungen bedarf es in der Regel methodischer Kenntnisse sowie Erfahrungen, die über die schriftliche Arbeit hinausgehen. Die Arbeit zeigt gesammeltes Wissen, welches in verständlicher Weise verfasst wurde. Schwerpunkt lag dabei auf der kritischen Betrachtung von Praxis und Wissenschaft. Die Bachelorarbeit soll die Basis für eine darauf folgende Neugründung eines Un-ternehmens darstellen. Die Arbeit wird eine strategische Positionierung beinhalten. Gekoppelt mit einer kunden- und konkurrenzbezogenen Analyse, die die Basis einer Neugründung ist