7,387 research outputs found
The Impact of the Tau Mutation on Reproductive Function in the Golden Hamster
The tau mutation affects the circadian system of the golden hamster primarily by decreasing the period of the activity cycle from 24 to 20 hours. To study the effect of this mutation on reproductive function in the golden hamster, 3 experiments have been designed. In the first experiment, wild-type and tau female hamsters will be maintained in conditions of 14:10 LD and 11.7:8.3 LD, respectively. Blood samples will be taken and analyzed by radioimmunoassay (RIA) to determine the timing of the proestrus LH surge. In the second experiment, wild-type and tau males will be transferred to shortened photoperiods of 10:14 LD and 8.3:11.7 LD, respectively, and testicular length and width will be used as a measure of the onset of testicular regression and subsequent recrudescence. In the final experiment, wild-type and tau females will be transferred to conditions of 10:14 LD and 8.3:11.7 LD, respectively, and the time to the onset of anestrus will be recorded. It is expected that in the tau females, the preovulatory LH surge will occur 8.4 hours after lights-on. The onset of gonadal regression, recrudescence, and anestrus will occur 16.7% [(24 hours - 20 hours)/24 hours] sooner in the mutant hamster when measured in absolute time. When the time to the onset of these processes is measured in light cycles, however, it is probable that these events occur within the same number of light cycles in both the wild-types and the tau hamsters. The basic hypothesis is that the main impact of the tau mutation will be on the timing of these specific reproductive phenomena, but the fundamental physiological characteristics of these events will remain unaffected. These results would suggest that the timing of the preovulatory LH surge and the occurrence of gonadal regression, recrudescence, and anestrus in a shortened photoperiod are driven by the same neural oscillator that regulates the period of the activity cycle in the golden hamster
Shopper Questionnaire Surveys at Convenience Foodstores in West Yorkshire
This report sets out the preliminary findings of a series of
questionnaire shopper surveys at five convenience foodstores in
West Yorkshire. The surveys, which form the second phase of a
current research study, followed an earlier series of surveys,
the results of which were given in a report produced earlier this
year 1 .
The questionnaire surveys were carried out in May-June 1983
and the information obtained comprised that on the shopper and
shopper's household together with trip, travel mode and
attitudinal data
Trip Generation of Selected Industrial Groups.
This paper determines the factors influencing commercial vehicle trip generation for selected industrial groups, and quantifies their effects using multiple regression analysis. Two methods of selecting the groups were adopted: one using eight of the Standard Industrial Classes; and one which attempted to put industries having similar vehicle generation characteristics into the same group, by subdividing SIC groups or by grouping together industries with similar manufacturing or trading processes. The survey combined an initial interview of firm's management about the operations of the firm with a recording by the firm of their travel data, using a sample of firms in the West Yorkshire metropolitan area. Of 22 relationships developed, 15 were considered acceptable descriptors of the variations in trip making, but only in 3 cases did a single variable (such as total floor area or total employees) account for more than 70 percent of the variation, and no single variable type gave the best fit for the various groups investigated
Parking and Vehicle Activity Surveys at Large Convenience Foodstores in West Yorkshire: Results and Guidelines for Design
This report sets out the main results and conclusions of a series of vehicular activity,and parking surveys at thirteen convenience food stores in West Yorkshire. The surveys, carried out in the period February - June 1982, were undertaken at stores ranging from a typical high street supermarket to large superstores. Data on vehicular flows and-parking indices were obtained at twelve stores; in addition registration number surveys were completed at three stores to allow customer parking durations to be determined
- …