946 research outputs found

    Device independent quantum key distribution secure against coherent attacks with memoryless measurement devices

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    Device independent quantum key distribution aims to provide a higher degree of security than traditional QKD schemes by reducing the number of assumptions that need to be made about the physical devices used. The previous proof of security by Pironio et al. applies only to collective attacks where the state is identical and independent and the measurement devices operate identically for each trial in the protocol. We extend this result to a more general class of attacks where the state is arbitrary and the measurement devices have no memory. We accomplish this by a reduction of arbitrary adversary strategies to qubit strategies and a proof of security for qubit strategies based on the previous proof by Pironio et al. and techniques adapted from Renner.Comment: 13 pages. Expanded main proofs with more detail, miscellaneous edits for clarit

    Six new species of Utricularia (Lentibulariaceae) from Northern Australia

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    Six new species of Utricularia (Lentibulariaceae) are recognised from northern Australia. Descriptions of the new species Utricularia albertiana R.W.Jobson & Baleeiro, U. bidentata R.W.Jobson & Baleeiro, U. hamata R.W.Jobson & M.D.Barrett, U. magna R.W.Jobson & M.D.Barrett, U. papilliscapa R.W.Jobson & M.D.Barrett, and U. limmenensis R.W.Jobson (Lentibulariaceae) are provided. Diagnostic features for all six species are illustrated, and distribution, habitat, and conservation status are discussed

    The Role of Spokesperson in Ambiguous and Complex Crises: The CDC and Anthrax

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    This study evaluates the role of spokespersons in complex organizations facing ambiguous crises. Specifically, the Centers for Disease Control and Prevention’s (CDC) response to the anthrax crisis in 2001 is offered as a case study. A content analysis of the print media coverage of the anthrax crisis reveals that many claiming affiliation with the CDC spoke on behalf of the organization, resulting in what appeared to be a fragmented CDC message. The study concludes that the CDC’s failure to provide a central spokesperson contributed to the ambiguity of the situation

    Motion analysis of match-play in elite U12 to U16 age-group soccer players

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    The aim of this study was to quantify the motion demands of match-play in elite U12 to U16 age-group soccer players. Altogether, 112 players from two professional soccer clubs at five age-group levels (U12–U16) were monitored during competitive matches (n=14) using a 5 Hz non-differential global positioning system (NdGPS). Velocity thresholds were normalized for each age-group using the mean squad times for a flying 10 m sprint test as a reference point. Match performance was reported as total distance, high-intensity distance, very high-intensity distance, and sprint distance. Data were reported both in absolute (m) and relative (m min-1) terms due to a rolling substitute policy. The U15 (1.35±0.09 s) and U16 (1.31±0.06 s) players were significantly quicker than the U12 (1.58±0.10 s), U13 (1.52±0.07 s), and U14 (1.51±0.08 s) players in the flying 10 m sprint test (P U12, U13, U14), high-intensity distance (U16 > U12, U13, U14, U15), very high-intensity distance (U16 4 U12, U13), and sprint distance (U16 > U12, U13) than their younger counterparts (P<0.05). When the data are considered relative to match exposure, few differences are apparent. Training prescription for youth soccer players should consider the specific demands of competitive match-play in each age-group
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