900 research outputs found
Infrared remote sensing of cometary parent volatiles from the ground, air, and space
A balanced view of the present generation of infrared instruments for cometary compositional studies is presented. Ground-based instruments are compared with airborne and spaceborne capabilities. An attempt to give examples of the unique science achievable with each is made, and particular emphasis is on the unique aspects of a dedicated Cometary Composition Telescope in earth orbit for investigating the chemical and structural heterogeneity of the cometary nucleus
Unbounded randomness certification using sequences of measurements
Unpredictability, or randomness, of the outcomes of measurements made on an
entangled state can be certified provided that the statistics violate a Bell
inequality. In the standard Bell scenario where each party performs a single
measurement on its share of the system, only a finite amount of randomness, of
at most bits, can be certified from a pair of entangled particles
of dimension . Our work shows that this fundamental limitation can be
overcome using sequences of (nonprojective) measurements on the same system.
More precisely, we prove that one can certify any amount of random bits from a
pair of qubits in a pure state as the resource, even if it is arbitrarily
weakly entangled. In addition, this certification is achieved by near-maximal
violation of a particular Bell inequality for each measurement in the sequence.Comment: 4 + 5 pages (1 + 3 images), published versio
Almost quantum correlations
Quantum theory is not only successfully tested in laboratories every day but also constitutes a robust theoretical framework: small variations usually lead to implausible consequences, such as faster-than-light communication. It has even been argued that quantum theory may be special among possible theories. Here we report that, at the level of correlations among different systems, quantum theory is not so special. We define a set of correlations, dubbed 'almost quantum', and prove that it strictly contains the set of quantum correlations but satisfies all-but-one of the proposed principles to capture quantum correlations. We present numerical evidence that the remaining principle is satisfied too. © 2015 Macmillan Publishers Limited
Teachers\u27 perceptions of online modules to promote professional learning of ICT
Online professional learning has the potential to be a cost effective, flexible approach that can reach large numbers of teachers. However, there are many factors that need to be evaluated in developing successful online approaches that impact on teaching pedagogy and student learning. This paper outlines one phase of a research study conducted on behalf of an Australian state-based Department of Education to evaluate the transfer of professional learning from online modules about the integration of ICT to the practices of K-12 classroom teachers
Pharmacodynamic Activity of Ceftobiprole Compared with Vancomycin versus Methicillin-Resistant \u3cem\u3eStaphylococcus aureus\u3c/em\u3e (MRSA), Vancomycin-Intermediate \u3cem\u3eStaphylococcus aureus\u3c/em\u3e (VISA) and Vancomycin-Resistant \u3cem\u3eStaphylococcus aureus\u3c/em\u3e (VRSA) Using an In Vitro Model
Background This study compared the pharmacodynamics of ceftobiprole and vancomycin against methicillin-resistant Staphylococcus aureus (MRSA), vancomycin-intermediate S. aureus (VISA) and vancomycin-resistant S. aureus (VRSA) using an in vitro model.
Methods Two methicillin-susceptible S. aureus (MSSA), two community-associated (CA)-MRSA, one healthcare-associated (HA)-MRSA, three VISA and two VRSA were studied. The pharmacodynamic model was inoculated with a concentration of 1 × 106 cfu/mL and ceftobiprole dosed every 8 h (at 0, 8 and 16 h) to simulate the fCmax and t1/2 obtained after 500 mg intravenous (iv) every 8 h dosing (fCmax, 30 mg/L; t1/2, 3.5 h). Vancomycin was dosed every 12 h (at 0 and 12 h) to simulate fCmax and t1/2 obtained after 1 g iv every 12 h dosing (fCmax, 20 mg/L; t1/2, 8 h). Samples were collected over 24 h to assess viable growth.
Results Ceftobiprole T \u3e MIC of ≥100% (ceftobiprole MICs, ≤2 mg/L) was bactericidal (≥3 log10 killing) against MSSA, CA-MRSA, HA-MRSA, VISA and VRSA at 16 and 24 h. Vancomycin fAUC24/MIC of 340 (vancomycin MIC, 1 mg/L for MSSA and MRSA) resulted in a 1.8–2.6 log10 reduction in colony count at 24 h. Vancomycin fAUC24/MIC of 85–170 (vancomycin MIC, 2–4 mg/L for VISA) resulted in a 0.4–0.7 log10 reduction at 24 h. Vancomycin fAUC24/MIC of 5.3 (vancomycin MIC, 64 mg/L for VRSA) resulted in a limited effect.
Conclusions Ceftobiprole T \u3e MIC of ≥100% (ceftobiprole MICs, ≤2 mg/L) was bactericidal (≥3 log10 killing) against MSSA, CA-MRSA, HA-MRSA, VISA and VRSA at 16 and 24 h. Vancomycin was bacteriostatic against MSSA, MRSA and VISA, while demonstrating no activity against VRSA
Non-adaptive Measurement-based Quantum Computation and Multi-party Bell Inequalities
Quantum correlations exhibit behaviour that cannot be resolved with a local
hidden variable picture of the world. In quantum information, they are also
used as resources for information processing tasks, such as Measurement-based
Quantum Computation (MQC). In MQC, universal quantum computation can be
achieved via adaptive measurements on a suitable entangled resource state. In
this paper, we look at a version of MQC in which we remove the adaptivity of
measurements and aim to understand what computational abilities still remain in
the resource. We show that there are explicit connections between this model of
computation and the question of non-classicality in quantum correlations. We
demonstrate this by focussing on deterministic computation of Boolean
functions, in which natural generalisations of the Greenberger-Horne-Zeilinger
(GHZ) paradox emerge; we then explore probabilistic computation, via which
multipartite Bell Inequalities can be defined. We use this correspondence to
define families of multi-party Bell inequalities, which we show to have a
number of interesting contrasting properties.Comment: 13 pages, 4 figures, final version accepted for publicatio
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