The October 1998 Flood of the Upper Guadalupe River System, Central Texas

The October 1998 flood on the upper Guadalupe River system was produced by a 24-hour precipitation amount of 483 mm at one station, over 380 mm at several other stations, and up to 590 mm over five days, precipitation amounts greater than the 100-year storm as prescribed in Weather Bureau Technical Papers 40 (1961) and 49 (1964). This study uses slope-area discharge estimates and published discharge and precipitation data to analyze flow characteristics of the three major branches of the Guadalupe River on the Edwards Plateau. The main channel of the Guadalupe has a single large flood-control structure at Canyon Dam and five flood dams on the tributary Comal River. On the upper San Marcos River there are five detention dams that regulate 80% of its drainage. The Blanco River, which has no structural controls, generated a peak discharge of 2,970 m3/s from a 1,067 km2 basin. Downstream of Canyon Dam, the Guadalupe River generated a peak discharge greater than 3,000 m3/s from an area of 223 km2. The event exceeded the capacity of both the Comal River and San Marcos flood-control projects and produced spills that inundated areas greater than the 100-year floodplain defined by the Federal Emergency Management Agency.

The Specific Status of the Narrow-Skulled Vole (Subgenus Stenocranius Kashchenko) in North America

On morphological and zoogeographical grounds, discussed in the present paper, it is concluded that the narrow-skulled vole in North America, previously designated Microtus (Stenocranius) miurus Osgood, is conspecific with the Eurasian M. (Stenocranius) gregalis Pallas. Fourteen subspecies in Eurasia and 5 in North America are now recognized, but it is probable that the number in Eurasia will be reduced through future investigation. The Eurasian subspecies of this vole comprise two major groups, of which one occupies the tundra zone and the other occurs across central Asia below latitude 60° N; their geographic ranges are largely separate but evidently become confluent in northeastern Siberia. The members of the northern group of Eurasian subspecies and the North American forms are closely related; the present distribution of the latter indicates post-glacial dispersal from the Amphiberingian Refugium. It is believed that the tundra-inhabiting voles in Eurasia likewise survived the Pleistocene glaciations in northern refugia, while the members of the southern group of subspecies probably represent populations that survived south of the limits of the continental glaciers. The ranges of the two Eurasian groups probably have become confluent during post-glacial time in northeastern Siberia as a result of the southward spread of the northern forms. At least, the subspecies having the intervening range closely resembles members of the northern group. Some of the ecological and ethological characteristics of these voles are briefly discussed. The chromosome number of one of the North American subspecies of narrow-skulled vole was determined to be 54; this is the first time that the chromosomes of a member of the subgenus Stenocranius have been investigated. A karyogram has been included. German abstract: Auf morphologischen und tiergeographischen Grundlagen, die in dieser Arbeit besprochen wurden, ist festgestellt worden, daß die schmalschädlige Wiihlmaus in Nordamerika, friiher Microtus (Stenocranius) miurus Osgood bezeichnet, mit der palaearktischen Art M. (Stenocranius) gregalis Pallas identisch ist. Zur Zeit gelten 14 Unterarten in Eurasien und 5 in Nordamerika als unterscheidbar; vermutlich aber wird die Zahl der palaearktischen Unterarten durch eingehendere Untersuchungen künftig vermindert werden. Auf Grund ihrer Verbreitung bilden die palaearktischen Unterarten zwei beinahe vollständig getrennte Gruppen. Die Wühlmäuse der nördlichen Gruppe bewohnen die Tundrazone, während die Vertreter der zweiten Gruppe über Mittelasien südlicher als 60° N.B. verbreitet sind. Die Verbreitungsgebiete der zwei Gruppen verbinden sich anscheinend. Die nordamerikanischen schmalschädligen Wühlmäuse sind mit den in der Tundrazone vorkommenden palaearktischen Formen nahe verwandt; sie haben sich wahrscheinlich während der Postglazialzeit aus dem Amphiberingschen Refugium verbreitet. Möglicherweise überlebten die tundrabewohnenden Wühlmäuse Eurasiens die Eiszeit ebenfalls in vereinzelten Refugien in Nordostsibirien, während die Formen der südlichen Gruppe sie jenseits der Grenzen des Festlandsgletschers überlebten. Wahrscheinlich wurden die zwei Verbreitungsgebiete dieser Art in Eurasien erst während der Postglazialzeit durch das Vordringen der nordischen Formen verbunden, da eine nähere Verwandtschaft zwischen den nördlichen und der dazwischenliegenden Unterart besteht. Einige ökologische und ethologische Eigentümlichkeiten dieser Wühlmäuse werden kurz besprochen. Es wurde festgestellt, daß eine der nordamerikanischen Unterarten der schmalschädligen Wühlmaus 54 Chromosomen hat; sie ist der einzige Vertreter der Untergattung Stenocranius, dessen Chromosomen untersucht worden sind.

Perception of the Internet as an Enabler of Scholarship among Postgraduate Students of the University of Ibadan, Oyo State, Nigeria

This paper investigates postgraduate students' perceptions of the Internet as an enabler of scholarship.The specific objectives of the study are: to ascertain the perception held by the postgraduate students on the Internet usage as an enabler of scholarship, and to determine what interventions are necessary to facilitate postgraduate students' adoption of the Internet as a tool for learning and research. The subjects of study are the postgraduate students of the University of Ibadan, Nigeria. A random sample of 100 students was selected with representation from each faculty of the university. A questionnaire instrument with a 12-item scale was designed and administered. Data analysis was done using the chi-square statistical method. The results show that majority of the postgraduate students have positive perceptions of the Internet as an enabler of information sourcing for learning and research. However some of these students have low self-efficacy in Internet use for information sourcing.