334 research outputs found

    Milk progesterone as a tool to improve fertility in dairy cows

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    Milk progesterone offers an opportunity to objectively study fertility in dairy cows, in contrast to traditional measures of dairy cow fertility, which in general are highly influenced by on-farm management decisions. The aim of this thesis was to study how milk progesterone could be used as a genetic and management tool to improve fertility in dairy cows. Progesterone-based measures were influenced by different systematic factors, e.g. breed, parity, season, housing and lameness, studied in a dataset from a Swedish experimental herd. The repeatabilities were higher for progesterone-based measures compared with traditional measures of fertility based on insemination data. If a cow had an atypical progesterone profile in one lactation, the risk of an atypical profile in the next lactation was increased. Genetic parameters for progesterone measures based on different milk sampling intervals were estimated in a British dataset. Heritability estimates were moderate, but decreased with increased sampling intervals. It was shown that progesterone analysis of monthly milk samples, resembling milk sampling as in the current Swedish milk recording system, could be used to increase the accuracy of genetic evaluation for an earlier start of cyclical ovarian activity after calving. Inclusion of monthly milk sampling for progesterone analysis in predictive models could also be used to identify cows with delayed ovarian cyclicity with a high accuracy already two months after calving. This enables an earlier treatment of ovarian dysfunction and therefore, probably, a shorter calving interval. In conclusion, this thesis shows that milk progesterone may be used for improved management and genetic evaluation of dairy cow fertility

    Model Reduction using a Frequency-Limited H2-Cost

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    We propose a method for model reduction on a given frequency range, without the use of input and output filter weights. The method uses a nonlinear optimization approach to minimize a frequency limited H2 like cost function. An important contribution in the paper is the derivation of the gradient of the proposed cost function. The fact that we have a closed form expression for the gradient and that considerations have been taken to make the gradient computationally efficient to compute enables us to efficiently use off-the-shelf optimization software to solve the optimization problem.Comment: Submitted to Systems and Control Letter

    How to become the Leader of the Mobile Telecom Industry

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    Five main observations have been made. First, the integration is likely to continue within the mobile telecom industry. Second, the value creation process will change significantly during the next few years. Third, the operators must reinvent their position in the value chain to maintain high profitability. Fourth, ecosystem keystones will capture most of the value. Fifth, flexibility will become even more important in the future. Both horizontal and vertical integration makes the companies larger and less flexible, which in turn makes it more difficult for them to adapt to the market and the rapidly changing consumer needs. However, it is through size, integration and cooperations that a company can take a keystone advantage position. To become a so called keystone, and be able to capture most of the value created within the industry, it is important to have the customer in focus and apply co-creation and the customers-as-innovators approach. By taking in the consumer early in a product development process, the risk of losing flexibility to changing consumer needs can be reduced. Currently, it is the operators and the mobile phone brands that are competing for the position as keystone within the mobile telecom industry

    Phase metrology with multi-cycle two-colour pulses

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    Strong-field phenomena driven by an intense infrared (IR) laser depend on during what part of the field cycle they are initiated. By changing the sub-cycle character of the laser electric field it is possible to control such phenomena. For long pulses, sub-cycle shaping of the field can be done by adding a relatively weak, second harmonic of the driving field to the pulse. Through constructive and destructive interference, the combination of strong and weak fields can be used to change the probability of a strong-field process being initiated at any given part of the cycle. In order to control sub-cycle phenomena with optimal accuracy, it is necessary to know the phase difference of the strong and the weak fields precisely. If the weaker field is an even harmonic of the driving field, electrons ionized by the field will be asymmetrically distributed between the positive and negative directions of the combined fields. Information about the asymmetry can yield information about the phase difference. A technique to measure asymmetry for few-cycle pulses, called Stereo-ATI (Above Threshold Ionization), has been developed by [Paulus G G, et al 2003 Phys. Rev. Lett. 91]. This paper outlines an extension of this method to measure the phase difference between a strong IR and its second harmonic

    A comprehensive transition matrix model for projecting production and resource consumption in reindeer herds

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    A deterministic herd model was developed for projecting the dynamic changes in reindeer herd size and structure under defined harvest policies. The model distinguishes between females, males and castrates up to an optional number of age-classes. Calves are further classified based on the age and status (present/absent) of their mother. The yearly cycle is divided up into a maximum of 11 time steps, including five grazing seasons. The model is described in general terms using the Leslie matrix approach in order to suit different computer implementations. The conventional Leslie matrix solution was extended so that nonlinear features and stochastic variation in performance parameters could be considered. Computational procedures for making detailed economic evaluations of harvest output and herd feed requirements or consumption are given. This general purpose model can be tailored to specific study conditions. An advantage of this is that the sensitivity to necessary approximations can be tested with the general purpose model. The model is intended for use in both research and extension work

    Growth and relationship of live weight to body measurements in semi-domesticated reindeer (Rangifer tarandus tarandus L.)

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    Estimation of live weight from measurements of body dimensions is useful in many management activities with domestic animals. In present study live weight was measured from 2932 female and 1037 male semi-domesticated reindeer (Rangifer tarandus tarandus L.) during different seasons in 1969-85. The age of reindeer varied between 1 day and 14 yrs. Back length (along back from second spinous process to base of tail) and chest girth (just behind front legs) were taken also from 1490 female and 510 male reindeer. The growth of reindeer from birth to adulthood was cumulative consisting of a rapid weight accretion during summers followed by a weight loss or stasis during winters. The mathematical analyses of the growth based on exponential solutions gave average values for growth of female and male reindeer. Body weight of females increased until the age of 4.5 yrs and that of males until the age of 5.5 yrs. During winter and spring body weight of hinds decreased 10 to 15 kg and that of stags 30 to 50 kg in different age groups. Significant linear regressions were found between live weight and back length (r = 0.809 and 0.892), live weight and chest girth (r = 0.860 and 0.872) and live weight and combined body measure (back length + chest girth) (r = 0.877 and 0.941) and live weight and body volume (r = 0.905 and 0.954, respectively) in female and male reindeer. Exponential regressions gave, however, the best estimations of live weight with combined body measure

    Leads Companion - En Androidapp för säljarna på Telavox

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    This report describes a bachelor thesis project realized as the final exercise in the Computer Science program at Lunds Tekniska Högskola, Campus Helsingborg. The thesis work was done as an Android app-development project at Telavox in Malmö, a company active in the IP-Telephony business. The purpose of the project was to develop an Android application to be used by the sellers at the company. The application is an implementation of an already existing web interface which is part of the company’s administrative system. An investigation about how elements of game-ification can be implemented in the application was also part of the project. The proposed users of the app are often located in areas with only 2G-mobile network coverage. Because of this methods for diminishing negative user experience due to long load times have been studied. The report shows that by using Lazy Load the amount of data communicated, and as a result load times, between server and client can be lowered. The conclusion is that to be able to use Lazy Load a restructuring of how the work is divided between server and client has to be made. In the developed app a different approach has been taken by the use of a cache file which hides load times from the user. The report also shows how it is possible by the use of the framework Fragments from Android API to develop an Android app targeted for devices with a broad range of screen sizes without the need to create several layout files for specific devices

    Influence of Plastic Dissipation on Apparent Fracture Energy Determined by a Three-Point Beding Test

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    A three-point bending test used for determining the fracture energy in modus I for wood perpendicular to the grain is studied, If the height of the specimen is varied, the results show a size effect, The specimens used in testing have been analyzed by finite element calculations with an anisotropic elasto-plastic material model in order to determine the influence of plastic dissipation. Analysis has been performed for three sizes of specimens where the height and length have been varied. The computational results are compared with experimental results

    Perceived Changes in Communicative Interaction in Atypical Parkinsonism

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    The aim of this study was to examine if atypical parkinsonism affects the communicative ability in conversational interaction. Fifteen persons close to individuals with atypical parkinsonism answered a questionnaire, “Assessment of Change in Communicative Interaction” (ACCI), estimating perceived change in interactive skills compared to before the onset of the disease. The study also examined if perceived change correlated with disease duration. The results showed that at group level, the participants experienced change in many aspects of conversational interaction, particularly regarding the affected person's speech, body communication, response latency, phrase length, word finding, and ability to make themselves understood. There was no correlation between perceived change and disease duration. In conclusion, results indicated that the communicative interaction of individuals with atypical parkinsonism is significantly affected and that information elicited from significant others can help define specific problem areas or foci of concern that need to be targeted in communicative intervention or at least considered in interaction with these persons

    MPLS based recovery mechanisms

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    Multi-protocol label switching (MPLS) integrates the label swapping forwarding paradigm with network layer routing. To deliver reliable service, MPLS requires a set of procedures to provide protection of the traffic carried on different paths. This requires that the label switching routers (LSRs) support fault detection, fault notification, and fault recovery mechanisms, and that MPLS signaling supports the configuration of recovery. The purpose of this work is to evaluate the different recovery mechanisms proposed by the IETF, by literature study and simulation experiments