1,127 research outputs found

    Truth Under Fire: The War and the Media

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    Over the last hundred years, the relationship between war and mass communication has become increasingly elaborate. Governments and private-sector organizations have found more and more ways to use the media in wartime, and the range of available technologies has expanded to include print, film, radio, television, and the Internet. The system that exists today, at the start of the twenty-first century, is the product of many twists and turns over the decades: an accretion of some strategies for wartime use of mass communication and a rejection of others. An understanding of this evolution is a starting point for crafting policies to minimize the perverse effects and realize the positive potential that mass communication holds

    A note on bounds for the cop number using tree decompositions

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    In this short note, we supply a new upper bound on the cop number in terms of tree decompositions. Our results in some cases extend a previously derived bound on the cop number using treewidth

    A dynamic systems approach to infant facial action

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    Journal ArticleWhat does it mean when a baby smiles? Is it an expression of enjoyment, a signal to a partner that rewards effective caretaking, or simply a muscular contraction? Do physically different types of smiles indicate different things? Should the social context in which an infant smiles inform our understanding of the smile? To address these questions, we apply insights and ideas from a dynamic systems perspective to anatomical, social interactive, and neurophysiological data on the development of infant facial action (Fogel, 1993; Fogel & Thelen, 1987; Thelen, 1995; Thelen & Smith, 1994)

    Hyperopic Cops and Robbers

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    We introduce a new variant of the game of Cops and Robbers played on graphs, where the robber is invisible unless outside the neighbor set of a cop. The hyperopic cop number is the corresponding analogue of the cop number, and we investigate bounds and other properties of this parameter. We characterize the cop-win graphs for this variant, along with graphs with the largest possible hyperopic cop number. We analyze the cases of graphs with diameter 2 or at least 3, focusing on when the hyperopic cop number is at most one greater than the cop number. We show that for planar graphs, as with the usual cop number, the hyperopic cop number is at most 3. The hyperopic cop number is considered for countable graphs, and it is shown that for connected chains of graphs, the hyperopic cop density can be any real number in $[0,1/2].

    UHF Modulation and Fourier Transform Differential Time Domain Techniques for Measuring Strain Via Fiber Optics

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    The design and manufacture of future space transportation and delivery systems will be strongly driven by safety, cost, maintenance and reliability considerations. Advanced composite structural components are likely to be a key element in realizing these system objectives. Composites have the additional potential of enabling the embedment of sensors for system health monitoring, which supports requirements for low cost safety, maintenance and repair diagnosis

    A Fiber Optic RF Resonant Cavity Sensor for Strain Sensing-Forrcs

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    A fiber optic vibration and strain sensor described by Rogowski et al [1] implemented a radio frequency (rf) phase locked loop in an optical strain gauge bonded to or embedded in a composite structure. A laser is modulated at radio frequency by a voltage controlled oscillator. The phase delay through the optical fiber transmission line is compared to the source oscillator, and the resulting error signal shifts the oscillator, locking the phase. Strain in the specimen (a composite panel) produces a change in optical phase length in the fiber. Tracking the frequency change gives a measure of the integrated strain transduced into the fiber from the strained panel. Strain level sensitivity on the order of 0.1 microstrains has been reported [1]. However, considerable confusion surrounds the performance of the reported sensor, since noise presumed to arise from cladding/core mode interference and splice reflections makes significant filtering necessary, reducing the bandwidth of the sensor, e.g., increasing the response time to detect strains [2]. This limits vibration control applications

    The Flash Pattern of Photosynthetic Oxygen Evolution after Treatment with Low Concentrations of Hydroxylamine as a Function of the Previous S1/S0-Ratio Further Evidence that NH2OH Reduces the Water Oxidizing Complex in the Dark

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    Flash induced oxygen evolution patterns of isolated PS II complexes from the cyanobacterium Synechococcus were measured with a Joliot-type electrode. By suitable preflash and dark adaptation procedures, samples were prepared in the state S1 (100%), as well as enriched in S0 (60% S0, 40% S,). After treatment with low concentrations of NH2OH (≤ 100 μм), the two flash patterns were identical. This is further evidence for a reduction of the water oxidizing complex by hydroxylamine in the dark. Two reduced states (S-1 and S-2) below S0 are formed by this reduction

    All smiles are positive, but some smiles are more positive than others.

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    Disagreement as to whether all smiling or specific types of smiling index positive emotion early in life was addressed by examining when infants produced different types of smiling and other facial expres-sions. Thirteen infants were observed weekly from 1 to 6 months of age. Smiling alone—without cheek raising or mouth opening—was relatively more likely than periods without smiling both when mothers were smiling and when infants were gazing at their mothers ' faces. Cheek-raise (Duchenne) smiling was relatively more likely than smiling alone only when mothers were smiling. Open-mouth (play) smiling was relatively more likely than smiling alone only when infants were gazing directly at mothers ' faces. Smiling involving both cheek raising and mouth opening was relatively likely both when mothers were smiling and when infants were gazing at mothers ' faces and became increasingly likely with age when both conditions co-occurred. The cheek-raise and open-mouth dimensions of smiling appear to be associated with, respectively, the amplification of processes of sharing positive affect and of visual engagement that are present to a lesser degree in smiling alone. In infancy, positive emotions such as joy are hypothesized to motivate and organize desired actions (Blehar, Lieberman, & Ainsworth, 1977; Cohn, Campbell, & Ross, 1991; Malatesta, Cul

    Reducing Protected Lands in a Hotspot of Bee Biodiversity: Bees of Grand Staircase-Escalante National Monument

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    Grand Staircase-Escalante National Monument is a federally protected area found in central southern Utah. Designated in 1996 by President William J. Clinton, it was recently reduced in size by President Donald J. Trump in a proclamation that turned the one large monument into three smaller ones. A long-term, standardized study of the bees had been conducted from 2000–2003, revealing 660 species. The bee communities of the area are characterized by being spatially heterogeneous; most of the bees occur in isolated areas, with only a few being both abundant and widespread. Here we examine what affect the recent resizing of the monument has on the number, and ecology, of the bees now excluded from monument boundaries. Using the new monument boundaries and the geographic coordinates associated with each bee, we derived new species lists for each of the three monuments, and compared them to each other, and to the excluded lands. All three monuments now protect unique faunas, with Bray–Curtis similarity values not exceeding 0.59%. Each monument now harbors species not found in the other two monuments. We found that 84 bee species are no longer protected by any of the three monuments. These 84 species were not concentrated in one area that is now excluded, but were scattered throughout the newly excluded lands. For some of the excluded bee species, there is no evidence that they are rare or imperiled, being widespread throughout the west. However, there is a concentration of bees in the southern and eastern former monument lands that represent range extensions from nearby hot deserts. In addition to numerous range extensions, the list of excluded bees also contains several undescribed species (newly discovered species that have not yet been named and described by taxonomists) and morphospecies (individuals that are morphologically distinct, but that require additional research before species designations can be made). This indicates that the bee communities housed in these excluded areas would benefit from additional scientific inquiry. The areas now excluded from monument protections house a greater proportion of the original GSENM bee community than any of the three new monument units. We conclude this paper by discussing what the smaller monuments might mean for bee conservation in this hot spot of bee biodiversity and suggest that bee communities here and elsewhere should be taken into account when conservation decisions are being made
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