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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

Vyhodnocení růstové schopnosti potomstva býků specializovaných masných plemen skotu

Večeře, Martin January 2019 (has links)
The thesis is focused on the growth intensity of Aberdeen Angus, Charolais and Limousine. In experiment A, 152 male animals were monitored. These bulls came from organic and conventional breeding. For bulls, the date of birth, birth weight, father's line, date of sale, and live weight of bulls at sale were followed. Experiment B included 88 female heifers. Within each breed heifers came from conventional and organic breeding. Heifers were monitored for birth date, birth weight, father's line, weight at 120 and 210 days. Significant differences (p < 0.01) were found in the evaluation of the weights of individual monitored parameters between bulls and heifers, which are confirmed by the rule that females have lower birth weight (37 kg) than males (40 kg). However, at 120 days of age, weights were higher in heifers (177 kg) compared to bulls (148 kg). In the evaluation of breeding effect, the highest (p < 0.01) weights were found in Charolais (bulls 163 kg, heifers 187 kg).
2

Výsledky plodnosti po inseminaci a embryotransferu u skotu / Fertility Results in Beef Cattle: Insemination v. Embryo Transfer

KOČOVSKÁ, Michaela January 2015 (has links)
This thesis focuses on the fertility and fertility results in a monitored breeding herd of Limousin beef cattle. It includes a brief discussion of calf birth weights, their viability, and the time of calving. Taking this information into account, the main objective of this thesis is to present concise and accurate information regarding the age of purebred and crossbred heifers when they are first included in the reproduction process. The thesis also aims to evaluate the pregnancy success rates for insemination, embryo transfer, and natural breeding. Finally, the thesis tracks the calving difficulties experienced by cows and heifers after artificial reproduction methods and natural breeding. The conclusion includes calf birth weight figures and identifies the weight difference between newborn bulls and heifers. The results were evaluated using basic statistical characteristics. The collected data was analyzed according to the breeding method used and taking into account whether a cow or a heifer was involved. The age of purebred heifers during their first breeding is 26.1 months. The age of crossbred heifers included in the reproduction process as embryo recipients was 22.6 months. In the case of natural breeding, the crossbred heifers were first included at the age of 28 months due to the seasonality of the breeding season. The pregnancy success rate for first breeding by insemination is comparable to that for embryo transfer 62% and 63% respectively; in the case of natural breeding, the success rate is 92%. The highest number of easy births was determined for natural breeding (95%), followed by insemination (89%), and embryo transfer (only 61%). The birth weight of heifers was 2 kg less than that of bulls, and thus the number of easy births was higher. The average birth weight in 2014 was 41 kg. The top calving time was between midnight and 4:00 am (30% of the breeding cows).
3

Analýza chování vybraných kategorií skotu / Analysis of the behaviour of selected categories of breeding cows

VESELÁ, Tereza January 2014 (has links)
The aim of this thesis was to assess the differences in behavior of the two categories of beef cattle of Limousine breed, reared in the system without market production of milk, specifically heifers and cows with calves. Two seasons were selected (summer and winter) for the observation and the accent was on observing basic categories of behavior, such as feed intake, rest, standing and movement. The place where the research took place was the farm "Černěveský háj" located on the boundary of Strakonice, Prachatice and Budějovice district. Both behavioral studies were conducted for whole twenty-four hours. For night monitoring hunting camera with programmable video recording was used. The recorded data were written to the ethogram using descriptive interval method with length of interval of 10 minutes. During both observations the fundamental rules of ethology were respected. Traced values were evaluated by absolute time, its percentage and frequency and were subsequently completed with appropriate description. The results from this ethological research of heifers and cows with calves during two different seasons show that older cows have more regular and more keep basic categories of behavior during the day and more extend their regular behavior even throughout the year. Older subjects are able to make better use of pasture than heifers and address to it more time of the day (40% resp. 35%). During consummation of preserved feed ration heifers shortened their feed intake compared to cows (39% resp. 31%). By heifers there was also significant movement restriction, but to a lesser extent than in the case of cows. At the same time heifers prolonged period of rest from 33% to 50%. In conclusion, the obtained results show that the area in which the cows are kept is suitable for raising beef cattle without market production of milk. The breeder could only focus more on supplementing of graze with elements supporting natural welfare of beef cattle in year-round grazing.
4

The Role of Informal Transit in New York City: A Case Study of Commuter Vans in Eastern Queens

January 2017 (has links)
abstract: Informal public transport is commonplace in the developing world, but the service exists in the United States as well, and is understudied. Often called "dollar vans", New York's commuter vans serve approximately 120,000 people every day (King and Goldwyn, 2014). While this is a tiny fraction of the New York transit rider population, it is comparable to the total number of commuters who ride transit in smaller cities such as Minneapolis/St Paul and Phoenix. The first part of this study reports on the use of commuter vans in Eastern Queens based on a combination of surveys and a ridership tally, all conducted in summer 2016. It answers four research questions: How many people ride the vans? Who rides the commuter vans? Why do they ride commuter vans? Do commuter vans complement or compete against formal transit? Commuter van ridership in Eastern Queens was approximately 55,000 with a high percentage of female ridership. Time and cost savings were the main factors influencing commuter van ridership. Possession of a MetroCard was shown to negatively affect the frequency of commuter van ridership. The results show evidence of commuter vans playing both a competing and complementary role to MTA bus and subway transit. The second part of this study presents a SWOT analysis results of commuter vans, and the policy implications. It answers 2 research questions: What are the main strengths, weaknesses, opportunities and threats of commuter vans in Eastern Queens? and How do the current policies, rules and regulations affect commuter van operation? The SWOT analysis results show that the commuter van industry is resilient, performs a necessary service, and, with small adjustments that will help reduce operating costs and loss of profits have a chance of thriving in Eastern Queens and the rest of New York City. The study also discusses the mismatch between policy and practice offering recommendations for improvement to ensure that commuter vans continue to serve residents of New York City. / Dissertation/Thesis / Masters Thesis Urban and Environmental Planning 2017
5

Vehicle-to-Vehicle Inductive Charge Transfer Feasibility and Public Health Implications

Dutta, Promiti January 2021 (has links)
There has been an increased push away from the traditional combustion-engine powered vehicle due to environmental, health, and political concerns. As a result, alternative methods of transportation such as electric vehicles (EVs) have gaining popularity in the market. However, the EVs are not penetrating the market as quickly as expected, due in part to a combination of range, charge anxiety, and their financial costs. EVs cannot travel far due to limited driving range and require longer charge times than combustion-engine powered vehicles to recharge. Coupled with a lacking infrastructure for charging, the feasibility of an all-electric transportation market is still not possible. We propose a novel system in which we study and characterize the feasibility of increasing the effective driving range of a battery electric vehicle by utilizing inductive charge transfer to create an ad-hoc charging network where vehicles can “share” charge with one another. The application of wireless charge transfer from vehicle-to-vehicle (V2V) is the first of its kind and does not require any changes to current metropolitan infrastructures. Through the use of computer networking and communications algorithms, we analyze real-world commuter and taxi data to determine the potential effectiveness of such a system. We propose a participation and incentive mechanism to encourage participation in this network that enables the system to be functional.To illustrate proof of principle for V2V charging at traffic lights, we simulate a simplified model in which vehicles only exchange charge at traffic lights without coordination with other vehicles. Using a greedy heuristic, vehicles only exchange charge if they happen to meet another vehicle that has charge to share. The heuristic is greedy since decisions are made at each iteration with longer optimality not being considered. We are able to demonstrate an increase in effective driving range of EVs using these simplistic assumptions. In this thesis, we develop and quantify a complete simulation framework, which allows EVs to operate using charge sharing. We analyze data from the United States Department of Transportation, New York City Taxi and Limousine Commission, and Regional New York City data sources to understand the cumulative driving distance distributions for passenger/commuter vehicles and taxicabs in large metropolitan areas such as New York City. We show that the driving distributions can best be represented as heavy-tail distribution functions with most commuter vehicles not requiring additional charge during a typical day’s usage of their vehicle as compared to taxicabs, which regularly travel more than 100 miles during a 12-hour shift. We develop and parameterize several variables for input into our simulation framework including driving distance, charge exchange heuristics, models for determining pricing of charge units, traffic density, and geographic location. The inclusion of these parameters helps to build a framework that can be utilized for any metropolitan area to determine the feasibility of EVs. We have performed extensive evaluation of our model using real data. Our current simulations indicate that we can increase the effective distance that an electric vehicle travels by a factor of at least 2.5. This increased driving range makes EVs a more feasible mode of transportation for fleet vehicles such as taxicabs that rely heavily on commuting long cumulative distances. We have identified areas for future improvement to add further parameters to make the model even more sensitive. Finally, we focus on the application of our charge sharing framework in a real-world application for utilizing this methodology for the New York City bus system. In partnership with the New York City MTA, we launched a feasibility study of converting the currently majority hybrid bus fleet into a complete electric bus fleet with charging available at bus stops during scheduled bus stops. Unlike the earlier charge sharing framework, this simulation focuses on discrete distances that are traveled by the bus before having an opportunity to charge at the next bus stop. In this scenario, a large source of variability is the amount of time that the bus is able to stop at a bus stop for charging since this is determined by the amount of time needed to successfully embark and disembark the passengers at the given bus stop. This particular variability impacts how much charge the bus is able to gain during any given stop. We conclude with a list of opportunities for future work in expanding the model with additional parameters and conclusions of our work. Further, we identify areas of further research that outline the potential positive and negative outcomes from a charge sharing system that can be extended to various other applications including micro-mobility applications such as electric scooters and bicycles.

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