283 research outputs found

    Hot Isostatic Press (Hip) Vitrification of Radwaste Concretes

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    Properly formulated and properly ``canned`` radwaste concretes can be readily hot-isostatically-pressed (HIPed) into materials that exhibit performance equivalent to typical radwaste-type glasses. The HIPing conditions (temperature/pressure) required to turn a concrete waste form into a ``vitrified`` waste form are quite mild and therefore consistent with both safety and high productivity. This paper describes the process and its products with reference to its potential application to Idaho Chemical Processing Plant (ICPP) reprocessing wastes

    The Edit Distance to k-Subsequence Universality

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    A word u is a subsequence of another word w if u can be obtained from w by deleting some of its letters. In the early 1970s, Imre Simon defined the relation ?_k (called now Simon-Congruence) as follows: two words having exactly the same set of subsequences of length at most k are ?_k-congruent. This relation was central in defining and analysing piecewise testable languages, but has found many applications in areas such as algorithmic learning theory, databases theory, or computational linguistics. Recently, it was shown that testing whether two words are ?_k-congruent can be done in optimal linear time. Thus, it is a natural next step to ask, for two words w and u which are not ?_k-equivalent, what is the minimal number of edit operations that we need to perform on w in order to obtain a word which is ?_k-equivalent to u. In this paper, we consider this problem in a setting which seems interesting: when u is a k-subsequence universal word. A word u with alph(u) = ? is called k-subsequence universal if the set of subsequences of length k of u contains all possible words of length k over ?. As such, our results are a series of efficient algorithms computing the edit distance from w to the language of k-subsequence universal words

    Ionization dynamics in expanding clusters studied by XUV pump probe spectroscopy

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    he expansion and disintegration dynamics of xenon clusters initiated by the ionization with femtosecond soft x ray extreme ultraviolet XUV pulses were studied with pump probe spectroscopy using the autocorrelator setup of the Free Electron LASer in Hamburg FLASH facility. The ionization by the first XUV pulse of 92 eV photon energy 8 1012 W cm amp; 8722;2 leads to the generation of a large number of quasi free electrons trapped by the space charge of the cluster ions. A temporally delayed, more intense probe 4 1013 W cm amp; 8722;2 pulse substantially increases a population of nanoplasma electrons providing a way of probing plasma states in the expanding cluster by tracing the average charge of fragment ions. The results of the study reveal a timescale for cluster expansion and disintegration, which depends essentially on the initial cluster size. The average charge state of fragment ions, and thus the cluster plasma changes significantly on a timescale of 1 3 p

    Measuring Bird Damage to Three Fruit Crops: A Comparison of Grower and Field Estimates

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    Birds are common pests in fruit orchards. They frequently consume and damage fruit resulting in decreased yields for growers. The true extent of damage is difficult to measure. Producer surveys are often implemented to estimate damage, but the accuracy of these estimates is uncertain. We compared damage estimates obtained through field studies with estimates from a producer survey for three fruit crops: wine grapes, sweet cherries, and ‘Honeycrisp’ apples. We also analyzed relationships between use of various damage management methods and levels of bird damage. We found wine grape and sweet cherry growers accurately assessed bird damage, while ‘Honeycrisp’ apple growers may overestimate damage. Growing region appears to be an important damage predictor for wine grape and sweet cherry crops. Significant relationships between management methods and damage were positive, suggesting growers only use these methods when bird damage is substantial

    Toward Human-Carnivore Coexistence: Understanding Tolerance for Tigers in Bangladesh

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    Fostering local community tolerance for endangered carnivores, such as tigers (Panthera tigris), is a core component of many conservation strategies. Identification of antecedents of tolerance will facilitate the development of effective tolerance-building conservation action and secure local community support for, and involvement in, conservation initiatives. We use a stated preference approach for measuring tolerance, based on the ‘Wildlife Stakeholder Acceptance Capacity’ concept, to explore villagers’ tolerance levels for tigers in the Bangladesh Sundarbans, an area where, at the time of the research, human-tiger conflict was severe. We apply structural equation modeling to test an a priori defined theoretical model of tolerance and identify the experiential and psychological basis of tolerance in this community. Our results indicate that beliefs about tigers and about the perceived current tiger population trend are predictors of tolerance for tigers. Positive beliefs about tigers and a belief that the tiger population is not currently increasing are both associated with greater stated tolerance for the species. Contrary to commonly-held notions, negative experiences with tigers do not directly affect tolerance levels; instead, their effect is mediated by villagers’ beliefs about tigers and risk perceptions concerning human-tiger conflict incidents. These findings highlight a need to explore and understand the socio-psychological factors that encourage tolerance towards endangered species. Our research also demonstrates the applicability of this approach to tolerance research to a wide range of socio-economic and cultural contexts and reveals its capacity to enhance carnivore conservation efforts worldwide
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