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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Investigation of Automated Activity Monitoring Systems for Reproduction in Dairy Cattle

Neves, Rafael 26 July 2011 (has links)
This thesis is an investigation of the reproductive performance of dairy herds managed using automated activity monitoring systems for heat detection (AHD) in comparison to herds using timed artificial insemination programs (TAI). Two approaches were taken: a randomized clinical trial and a retrospective cross-sectional study. In the field trial, pregnancy risk (PR) was not different between the AHD (14.6%) and TAI program (15.9%). Overall, time to pregnancy, time to 1st service and time to 2nd service were not different between breeding programs. In the observational study, annual herd-summary reproductive performance in farms using AHD and TAI were not different. Finally, a retrospective analysis in herds that were using AHD for more than one year compared the years before and after adoption of the system. A significant increase of PR and insemination risk was found. In conclusion, AHD systems had comparable reproductive performance to TAI-based programs. / Ontario Ministry of Agriculture, Food and Rural Affairs. Gencor and SCR Engineers Ltd.
2

Factors influencing nightly activity of deer mice (Peromyscus maniculatus) in tallgrass prairie

Rehmeier, Ryan L. January 1900 (has links)
Doctor of Philosophy / Department of Biology / Donald W. Kaufman / Glennis A. Kaufman / Little is known about nightly activity patterns of nocturnal small mammals under natural conditions, and how these activity patterns might be affected by photoperiod, season, and sex, age, and reproductive status of individuals. The main objectives of this research were: 1) to find an appropriate method for marking individual deer mice (Peromyscus maniculatus) so that their activity could be monitored remotely; 2) to design a portable activity-monitoring system to investigate temporal patterns of shelter use by deer mice under natural conditions; 3) to determine the influence of environmental conditions such as photoperiod and season on nightly activity of deer mice; and 4) to compare effects of demographic or physiological factors such as sex, age, and reproductive status on nightly activity of deer mice at artificial burrows in tallgrass prairie. In general, commencement of activity was correlated positively with timing of sunset, and time of retirement to the burrow was correlated positively with sunrise. Among adults, males first emerged from the burrow earlier and made more trips of shorter duration in a night than did females, although total duration of trips was similar. Return visits and subsequent stays typically were shorter for males than females, but total time spent in the burrow and retirement time relative to sunrise were similar for both sexes. Young deer mice emerged significantly later, made more trips of shorter duration, spent less total time outside, and retired to their burrow earlier than adults. Reproductive females emerged later, made fewer trips of generally longer duration, and spent shorter total amounts of time away from the burrow each night than non-reproductive females. Return visits of reproductive females were of longer duration than non-reproductives, but total time spent inside and time of retirement for the night did not differ relative to reproductive status. From parturition through lactation, activity of females showed a number of directional trends. Results suggest that under natural conditions, activity patterns of deer mice are highly variable but responsive to both the changing physical environment and internal conditions related to sex-specific maximization of fitness.
3

Salvia suspension cultures as production systems for oleanolic and ursolic acid

Haas, Christiane, Hengelhaupt, Karl-Christoph, Kümmritz, Sibylle, Bley, Thomas, Pavlov, Atanas, Steingroewer, Juliane 26 January 2017 (has links) (PDF)
Oleanolic and ursolic acid (OA and UA) are triterpenic acids with diverse biological activities that are of interest to the pharmaceutical industry. To investigate the scope for producing these compound using cell suspension cultures of Salvia species, calli from S. officinalis, S. virgata and S. fruticosa were induced using several plant growth regulator (PGR) combinations. Eleven lines were selected for suspension induction from a pool of calli. Six suspension cultures were established successfully and cultivated in the Respiration Activity MOnitoring System® (RAMOS®) to obtain online data on their growth kinetics and to establish appropriate sampling schedules for the determination of their OA and UA production. Based on their observed growth behaviour, OA and UA contents, and aggregation properties, one suspension culture from each studied Salvia species was selected for further optimisation. The μmax values for these suspension cultures ranged from 0.20 to 0.37°d-1, their OA and UA contents were greater than 1.3 and 1.2 mg g-1, respectively, and they afforded maximum volumetric yields of 21.0 mg l-1 for OA and 32.8 mg l-1 for UA. These results will be useful in the development of a refined Salvia suspension-based process for OA and UA production.
4

Salvia suspension cultures as production systems for oleanolic and ursolic acid

Haas, Christiane, Hengelhaupt, Karl-Christoph, Kümmritz, Sibylle, Bley, Thomas, Pavlov, Atanas, Steingroewer, Juliane January 2014 (has links)
Oleanolic and ursolic acid (OA and UA) are triterpenic acids with diverse biological activities that are of interest to the pharmaceutical industry. To investigate the scope for producing these compound using cell suspension cultures of Salvia species, calli from S. officinalis, S. virgata and S. fruticosa were induced using several plant growth regulator (PGR) combinations. Eleven lines were selected for suspension induction from a pool of calli. Six suspension cultures were established successfully and cultivated in the Respiration Activity MOnitoring System® (RAMOS®) to obtain online data on their growth kinetics and to establish appropriate sampling schedules for the determination of their OA and UA production. Based on their observed growth behaviour, OA and UA contents, and aggregation properties, one suspension culture from each studied Salvia species was selected for further optimisation. The μmax values for these suspension cultures ranged from 0.20 to 0.37°d-1, their OA and UA contents were greater than 1.3 and 1.2 mg g-1, respectively, and they afforded maximum volumetric yields of 21.0 mg l-1 for OA and 32.8 mg l-1 for UA. These results will be useful in the development of a refined Salvia suspension-based process for OA and UA production.

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