5,745 research outputs found
Maximal entanglement of squeezed vacuum states via swapping with number-phase measurement
We propose a method to refine entanglement via swapping from a pair of
squeezed vacuum states by performing the Bell measurement of number sum and
phase difference. The resultant states are maximally entangled by adjusting the
two squeezing parameters to the same value. We then describe the teleportation
of number states by using the entangled states prepared in this way.Comment: 4 pages, 1 PS figure, RevTe
Evaluating antibiotics for use in medicine using a poloxamer biofilm model
BACKGROUND: Wound infections, due to biofilms, are a constant problem because of their recalcitrant nature towards antibiotics. Appropriate antibiotic selection for the treatment of these biofilm infections is important. The traditional in vitro disc diffusion method for antibiotic selection uses bacterial cultures grown on agar plates. However, the form of bacterial growth on agar is not representative of how bacteria grow in wounds and other tissue sites as here bacteria grow naturally in a biofilm. The aim of this research was to test a more appropriate method for testing antimicrobial efficacy on biofilms and compare with the standard methods used for antibiotic sensitivity testing. METHODS: Outer Membrane Protein analysis was performed on E.coli, Staphylococcus aureus, Pseudomonas aeruginosa, Proteus mirabilis and Acinetobacter juni when grown on Mueller Hinton agar ('quasi-biofilm state') and 30% Poloxamer hydrogel ('true- biofilm state). Susceptibility to antibiotics on 28 clinical isolates was determined using the modified Kirby Bauer disc diffusion method, on agar and 30% Poloxamer. RESULTS: Similar outer membrane proteins [OMPs] were identified in bacteria grown in a biofilm state and on a 30% poloxamer hydrogel, which were very different to the OMPs identified in bacteria grown on Mueller-Hinton agar and broth. There was a significant difference between the means of the clearance zones around the antibiotic discs on standard agar and poloxamer gels [P < 0.05]. The zones of clearance were generally smaller for poloxamer-grown bacteria than those grown on standard agar. Diffusion distances of various antibiotics through agar and 30% poloxamer showed no significant difference [P > 0.05]. CONCLUSION: The findings of this experiment suggest that poloxamer gel could be used as an appropriate medium on which to conduct biofilm antibiotic susceptibility tests as it enables bacteria to be grown in a state representative of the infected surface from which the culture was taken
Using ultra-thin parylene films as an organic gate insulator in nanowire field-effect transistors
We report the development of nanowire field-effect transistors featuring an
ultra-thin parylene film as a polymer gate insulator. The room temperature,
gas-phase deposition of parylene is an attractive alternative to oxide
insulators prepared at high temperatures using atomic layer deposition. We
discuss our custom-built parylene deposition system, which is designed for
reliable and controlled deposition of <100 nm thick parylene films on III-V
nanowires standing vertically on a growth substrate or horizontally on a device
substrate. The former case gives conformally-coated nanowires, which we used to
produce functional -gate and gate-all-around structures. These give
sub-threshold swings as low as 140 mV/dec and on/off ratios exceeding at
room temperature. For the gate-all-around structure, we developed a novel
fabrication strategy that overcomes some of the limitations with previous
lateral wrap-gate nanowire transistors. Finally, we show that parylene can be
deposited over chemically-treated nanowire surfaces; a feature generally not
possible with oxides produced by atomic layer deposition due to the surface
`self-cleaning' effect. Our results highlight the potential for parylene as an
alternative ultra-thin insulator in nanoscale electronic devices more broadly,
with potential applications extending into nanobioelectronics due to parylene's
well-established biocompatible properties
Emphasizing responder speed or accuracy modulates but does not abolish the distractor-induced quitting effect in visual search
Acknowledgements This research project was initially presented at the 2023 Australasian Experimental Psychology Conference (Lawrence et al., 2023c April 12â14). The authors would like to acknowledge the feedback and insights provided by Professor Allison Waters throughout the conceptualization and execution of this project. Funding This research was supported by a Griffith University New Researcher Grant awarded to RKL.Peer reviewedPublisher PD
Teleportation-based number state manipulation with number sum measurement
We examine various manipulations of photon number states which can be
implemented by teleportation technique with number sum measurement. The
preparations of the Einstein-Podolsky-Rosen resources as well as the number sum
measurement resulting in projection to certain Bell state may be done
conditionally with linear optical elements, i.e., beam splitters, phase
shifters and zero-one-photon detectors. Squeezed vacuum states are used as
primary entanglement resource, while single-photon sources are not required.Comment: 9 pages, 4 figures, Misprints are corrected. 3 figures for number sum
measurement are added. Discussion on manipulations are expanded. Calculations
for success probabilities are added. Fig.4 is adde
Beyond-adiabatic Quantum Admittance of a Semiconductor Quantum Dot at High Frequencies: Rethinking Reflectometry as Polaron Dynamics
Semiconductor quantum dots operated dynamically are the basis of many quantum
technologies such as quantum sensors and computers. Hence, modelling their
electrical properties at microwave frequencies becomes essential to simulate
their performance in larger electronic circuits. Here, we develop a
self-consistent quantum master equation formalism to obtain the admittance of a
quantum dot tunnel-coupled to a charge reservoir under the effect of a coherent
photon bath. We find a general expression for the admittance that captures the
well-known semiclassical (thermal) limit, along with the transition to lifetime
and power broadening regimes due to the increased coupling to the reservoir and
amplitude of the photonic drive, respectively. Furthermore, we describe two new
photon-mediated regimes Floquet broadening, determined by the dressing of the
QD states, and broadening determined by photon loss in the system. Our results
provide a method to simulate the high-frequency behaviour of QDs in a wide
range of limits, describe past experiments, and propose novel explorations of
QD-photon interactions
Tailoring teleportation to the quantum alphabet
We introduce a refinement of the standard continuous variable teleportation
measurement and displacement strategies. This refinement makes use of prior
knowledge about the target state and the partial information carried by the
classical channel when entanglement is non-maximal. This gives an improvement
in the output quality of the protocol. The strategies we introduce could be
used in current continuous variable teleportation experiments.Comment: 16 pages, 6 figures, RevTeX, made changes as recommended by referee,
other minor textual corrections, resubmitted to Phys. Rev.
Oil palm land conversion in ParĂĄ, Brazil, from 2006-2014: evaluating the 2010 Brazilian Sustainable Palm Oil Production Program.
Global models of biophysical suitability for oil palm consistently rank Brazil as having the greatest potential for expansion, with estimates as high as 238 Mha of suitable lands. In 2010, Brazil launched the Sustainable Palm Oil Production Program (SPOPP) to incentivize oil palm development without deforestation on as much as 30Mha. Here we examine oil palm expansion before and after the SPOPP?s launch. In ParÂŽa, the major oil palm producing state in Brazil, we analyze the extent and change in oil palm cultivation from 2006−2014 using satellite imagery, ground-truthed verification, site-based interviews, and rural environmental (land) registration data. Between 2006−2014, oil palm area (≥9 ha) expanded >200% to ∼219 000 ha. Of the ∼148 000 ha of oil palm developed, ∼91% converted pasturelands while ∼8% replaced natural vegetation, including intact and secondary forests. Although >80% of all oil palm parcels rest <0.5 km from intact forests, direct conversion of intact forests declined from ∼4% pre-SPOPP (2006−2010) to <1% post-SPOPP (2010−2014). Despite low and declining deforestation rates associated with oil palm expansion in ParÂŽa, our results also show a low area of oil palm development overall compared with reported land suitability. To explore potential contributing factors, we conducted semi-structured interviews with researchers, company representatives, and government officials involved in the sector to characterize the perceived factors influencing oil palm development and the role of agro-ecological suitability mapping among them. Interviews indicated that: (1) individual effects of suitability mapping efforts to encourage oil palm expansion on cleared areas, i.e. without deforestation, cannot be disentangled from pre-existing public and private deforestation reduction initiatives; and, (2) socio-economic constraints, e.g. high relative production costs and limited familiarity with this crop, appear to partially explain the major discrepancy between estimated potential suitable areas with realized oil palm development
Systematic review of the methods used in economic evaluations of targeted physical activity and sedentary behaviour interventions
The burden of noncommunicable diseases (NCD) on health systems worldwide is substantial. Physical inactivity and sedentary behaviour are major risk factors for NCD. Previous attempts to understand the value for money of preventative interventions targeting physically inactive individuals have proved to be challenging due to key methodological challenges associated with the conduct of economic evaluations in public health. A systematic review was carried out across six databases (Medline, SPORTSDiscus, EconLit, PsychINFO, NHS EED, HTA) along with supplementary searches. The review examines how economic evaluations published between 2009-March 2017 have addressed methodological challenges with the aim of bringing to light examples of good practice for future studies. Fifteen economic evaluations from four high-income countries were retrieved; there is a dearth of studies targeting sedentary behaviour as an independent risk factor from physical activity. Comparability of studies from the healthcare and societal perspectives were limited due to analystsâ choice in cost categories, valuation technique and time horizon differing substantially. The scarcity of and inconsistencies across economic evaluations for these two behaviours have exposed a mismatch between calls for more preventative action to tackle NCD and the lack of information available on how resources may be optimally allocated in practice. Consequently, this paper offers a table of recommendations on how future studies can be improved
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