82,609 research outputs found

    Essentially Derived Varieties in Ornamentals

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    The concept of Essentially derived varieties (EDVs) was introduced in the UPOV 1991 act to protect the interests of the breeder of the initial variety. When a variety is considered as an EDV, authorisation for commercial exploitation is needed from the breeder of the initial variety. There is considerable debate going on about which approaches to use for determining essential derivation and also which thresh-olds should be used in the different plant species. For determining whether a variety should be considered essentially derived from an existing variety two conceptually different approaches can be taken. The first one is based on genetic conformity, the second is more a forensic approach. For the implementation of the EDV concept using the conformity approach it is important that similarities between unrelated varieties can clearly be separated from essentially derived varieties. In the forensic approach the high genetic similarity between original variety and mutant is taken as a starting point. The basic idea is to calculate the probability that a second, putatively derived, variety would have a profile identical to the initial variety, given an independent breeding history. Both approaches will be illustrated and ways to implement the EDV concept will be discusse

    Mathematical methods and models for radiation carcinogenesis studies

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    Research on radiation carcinogenesis requires a twofold approach. Studies of primary molecular lesions and subsequent cytogenetic changes are essential, but they cannot at present provide numerical estimates of the risk of small doses of ionizing radiations. Such estimates require extrapolations from dose, time, and age dependences of tumor rates observed in animal studies and epidemiological investigations, and they necessitate the use of statistical methods that correct for competing risks. A brief survey is given of the historical roots of such methods, of the basic concepts and quantities which are required, and of the maximum likelihood estimates which can be derived for right censored and double censored data. Non-parametric and parametric models for the analysis of tumor rates and their time and dose dependences are explained

    Secure agent data integrity shield

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    In the rapidly expanding field of E-Commerce, mobile agent is the emerging technology that addresses the requirement of intelligent filtering/processing of information. This paper will address the area of mobile agent data integrity protection. We propose the use of Secure Agent Data Integrity Shield (SADIS) as a scheme that protects the integrity of data collected during agent roaming. With the use of a key seed negotiation protocol and integrity protection protocol, SADIS protects the secrecy as well as the integrity of agent data. Any illegal data modification, deletion, or insertion can be detected either by the subsequent host or the agent butler. Most important of all, the identity of each malicious host can be established. To evaluate the feasibility of our design, a prototype has been developed using Java. The result of benchmarking shows improvement both in terms of data and time efficiency
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