12,315 research outputs found

    A Note on Coincidence Isometries of Modules in Euclidean Space

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    It is shown that the coincidence isometries of certain modules in Euclidean nn-space can be decomposed into a product of at most nn coincidence reflections defined by their non-zero elements. This generalizes previous results obtained for lattices to situations that are relevant in quasicrystallography.Comment: 8 page

    RCIA and the Formation of Liturgical Piety

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    (Excerpt) Here is what I think the formation of liturgical piety means. You will recognize at once, I believe, these words which in December 1988 will celebrate their 25th birthday, words taken from the Constitution on the Sacred Liturgy, the first work of Vatican II. In what seems to me to be the very clearest and most amazing statement of its own zeal for putting the renewal of the liturgy as its first and foundational work, the Council said

    What Gets Changed? Sam Gets Changed?

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    (Excerpt) Most of what I learn about ritual and liturgy and church I learn from places that aren\u27t about ritual and liturgy and church-novels and poems and music and dance-and from people who don\u27t know the jargon but often know the Lord and the church. The tide of this presentation comes from one such fellow named Sam. He is a member of St. Henry Church on the southwest side of Cleveland. You\u27ll see a little of that church later on in this hour. We were there last fall, some of us from LTP, to make a video about the communion rite at Sunday mass. We had been looking for some parish where they really did the rite, and here we found one. So on one weekend we shot the video at their church and the producer interviewed a dozen or so parishioners and the clergy

    Reproductive Den Habitat Characterization of American Badgers (\u3cem\u3eTaxidea taxus\u3c/em\u3e) in Central California

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    The American badger (Taxidea taxus) is a species of special concern in California, and, as such, conservation measures are necessary. The goal of this study was to identify potential reproductive den habitat characteristics in order to more accurately predict critical reproductive habitat in central California grasslands. A paired study design was used to examine differences between reproductive and non-reproductive sites, and logistical regression was used to analyze the variables and produce two predictive models, one with biotic factors and one with abiotic factors. Badgers in central Californian grasslands appear to rely on both biotic and abiotic factors when selecting locations for reproductive den sites. Predictive biotic variables included amount of ground vegetation, presence of predators, presence of prey, and nearest shrub width. Predictive abiotic variables included distance to a drainage point and slopes at 10, 30, and 40 m from the den entrance. Integrating information from these models into conservation efforts will identify critical reproductive habitat and help form viable conservation strategies for the species

    Comparative statics for a three player differential game in resource economics - the case of exhaustible resources and varying allocations of initial stocks

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    Differential games combine strategic interactions between agents and optimization concerning time. Decisions made in the past determine the present and even the future .in pay off as well as in the opportunities available . for oneself and for the rival players, eventually too. Unfortunately, due to high complexity it is hard to find a Nash-equilibrium within a differential game and it is even harder to get some results in comparative statics. It is the purpose of the paper at hand to present findings concerning comparative statics in a differential game discussed by Wacker and Blank (1999). Comparative statics become available due to a routine solving for the open-loop Nash equilibrium for each parameter combination under consideration. A description of the routine . a 4 step simulation run which approximates the equilibrium numerically . was presented in an earlier Working Paper. In the earlier Paper Excel was applied as it is a wild spread tool. Here again Excel, its Solver and Macros constitute the main instruments; they are used to get repeated simulation runs for varying parameter constellations. The findings presented here concern varying allocations in initial stocks. Generalization to comparative statics in further parameters is in progress.

    Magic numbers in the discrete tomography of cyclotomic model sets

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    We report recent progress in the problem of distinguishing convex subsets of cyclotomic model sets Λ\varLambda by (discrete parallel) X-rays in prescribed Λ\varLambda-directions. It turns out that for any of these model sets Λ\varLambda there exists a `magic number' mΛm_{\varLambda} such that any two convex subsets of Λ\varLambda can be distinguished by their X-rays in any set of mΛm_{\varLambda} prescribed Λ\varLambda-directions. In particular, for pentagonal, octagonal, decagonal and dodecagonal model sets, the least possible numbers are in that very order 11, 9, 11 and 13.Comment: 6 pages, 1 figure; based on the results of arXiv:1101.4149 [math.MG]; presented at Aperiodic 2012 (Cairns, Australia

    Information can kill

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    Recent advances in understanding links between genes and the susceptibility to particular diseases have considerably increased the scope for predictive diagnosis. Methods. We analyse how the introduc- tion of predictive diagnosis affects patients�decisions to undergo medical screenings relying on a �rational choice�model. Findings. We show that predictive diagnosis can increase the number of fatalities from a deadly disease. Interpretation. Our result shows the necessity of careful further analysis and debate about the pros and cons of predictive diagnosis and the publication of medical research in general

    Solution of a uniqueness problem in the discrete tomography of algebraic Delone sets

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    We consider algebraic Delone sets Λ\varLambda in the Euclidean plane and address the problem of distinguishing convex subsets of Λ\varLambda by X-rays in prescribed Λ\varLambda-directions, i.e., directions parallel to nonzero interpoint vectors of Λ\varLambda. Here, an X-ray in direction uu of a finite set gives the number of points in the set on each line parallel to uu. It is shown that for any algebraic Delone set Λ\varLambda there are four prescribed Λ\varLambda-directions such that any two convex subsets of Λ\varLambda can be distinguished by the corresponding X-rays. We further prove the existence of a natural number cΛc_{\varLambda} such that any two convex subsets of Λ\varLambda can be distinguished by their X-rays in any set of cΛc_{\varLambda} prescribed Λ\varLambda-directions. In particular, this extends a well-known result of Gardner and Gritzmann on the corresponding problem for planar lattices to nonperiodic cases that are relevant in quasicrystallography.Comment: 21 pages, 1 figur

    Comparison of two sampling protocols and four home-range estimators using radio-tracking data from urban badgers Meles meles

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    Radio-telemetry is often the method of choice for studies of species whose behaviour is difficult to observe directly. However, considerable debate has ensued about the best way of deriving home-range estimates. In recent years, kernel estimators have become the most widely used method, together with the oldest and simplest method, the minimum convex polygon (MCP). More recently, it has been suggested that the local convex hull (LCH) might be more appropriate than kernel methods in cases where an animal’s home range includes a priori inaccessible areas. Yet another method, the Brownian bridge (BB), explicitly uses autocorrelated data to determine movement paths and, ultimately, home ranges or migration routes of animals. Whereas several studies have used simulation techniques to compare these different methods, few have used data from real animals. We used radio-telemetric data from urban badgers Meles meles to compare two sampling protocols (10-minute vs at least 30-minute inter-fix intervals) and four home-range estimators (MCP, fixed kernels (FK), LCH and BB). We used a multi-response permutation procedure and randomisation tests to compare overall patterns of fixes and degree of overlap of home ranges estimated using data from different sampling protocols, and a general linear model to compare the influence of sampling protocols and home-range estimator on the size of habitat patches. The shape of the estimated home ranges was influenced by sampling protocol in some cases. By contrast, the sizes and proportions of different habitats within home ranges were influenced by estimator type but not by sampling protocol. LCH performed consistently better than FK, and is especially appropriate for patchy study areas containing frequent no-go zones. However, we recommend using LCH in combination with other methods to estimate total range size, because LCH tended to produce smaller estimates than any other method. Results relating to BB are preliminary but suggest that this method is unsuitable for species in which range size is small compared to average travel speed.Marie-Curie Intra-European Fellowship (BSSUB - 24007); Defra WSC contract WM0304; Wildlife Biology granted the permit to upload the article to this repositor
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