1,219 research outputs found
Atmospheric composition affects heat- and mass-transfer processes
For environmental control system functions sensitive to atmospheric composition, components are test-operated in helium-oxygen and nitrogen-oxygen mixtures, pure oxygen, and air. Transient heat- and mass-transfer tests are conducted for carbon dioxide adsorption on molecular sieve and for water vapor adsorption on silica gel
Controlled Quantum Secret Sharing
We present a new protocol in which a secret multiqubit quantum state
is shared by players and controllers, where
is the encoding state of a quantum secret sharing scheme. The players may be
considered as field agents responsible for carrying out a task, using the
secret information encrypted in , while the controllers are
superiors who decide if and when the task should be carried out and who to do
it. Our protocol only requires ancillary Bell states and Bell-basis
measurements.Comment: 6 pages, 0 figure, RevTeX4; published version with minor change
Some Directions beyond Traditional Quantum Secret Sharing
We investigate two directions beyond the traditional quantum secret sharing
(QSS). First, a restriction on QSS that comes from the no-cloning theorem is
that any pair of authorized sets in an access structure should overlap. From
the viewpoint of application, this places an unnatural constraint on secret
sharing. We present a generalization, called assisted QSS (AQSS), where access
structures without pairwise overlap of authorized sets is permissible, provided
some shares are withheld by the share dealer. We show that no more than
withheld shares are required, where is the minimum number
of {\em partially linked classes} among the authorized sets for the QSS. Our
result means that such applications of QSS need not be thwarted by the
no-cloning theorem. Secondly, we point out a way of combining the features of
QSS and quantum key distribution (QKD) for applications where a classical
information is shared by quantum means. We observe that in such case, it is
often possible to reduce the security proof of QSS to that of QKD.Comment: To appear in Physica Scripta, 7 pages, 1 figure, subsumes
arXiv:quant-ph/040720
How to share a quantum secret
We investigate the concept of quantum secret sharing. In a ((k,n)) threshold
scheme, a secret quantum state is divided into n shares such that any k of
those shares can be used to reconstruct the secret, but any set of k-1 or fewer
shares contains absolutely no information about the secret. We show that the
only constraint on the existence of threshold schemes comes from the quantum
"no-cloning theorem", which requires that n < 2k, and, in all such cases, we
give an efficient construction of a ((k,n)) threshold scheme. We also explore
similarities and differences between quantum secret sharing schemes and quantum
error-correcting codes. One remarkable difference is that, while most existing
quantum codes encode pure states as pure states, quantum secret sharing schemes
must use mixed states in some cases. For example, if k <= n < 2k-1 then any
((k,n)) threshold scheme must distribute information that is globally in a
mixed state.Comment: 5 pages, REVTeX, submitted to PR
What potential has tobacco control for reducing health inequalities? The New Zealand situation
In this Commentary, we aim to synthesize recent epidemiological data on tobacco and health inequalities for New Zealand and present it in new ways. We also aim to describe both existing and potential tobacco control responses for addressing these inequalities. In New Zealand smoking prevalence is higher amongst Māori and Pacific peoples (compared to those of "New Zealand European" ethnicity) and amongst those with low socioeconomic position (SEP). Consequently the smoking-related mortality burden is higher among these populations. Regarding the gap in mortality between low and high socioeconomic groups, 21% and 11% of this gap for men and women was estimated to be due to smoking in 1996–99. Regarding the gap in mortality between Māori and non-Māori/non-Pacific, 5% and 8% of this gap for men and women was estimated to be due to smoking. The estimates from both these studies are probably moderate underestimates due to misclassification bias of smoking status. Despite the modest relative contribution of smoking to these gaps, the absolute number of smoking-attributable deaths is sizable and amenable to policy and health sector responses. There is some evidence, from New Zealand and elsewhere, for interventions that reduce smoking by low-income populations and indigenous peoples. These include tobacco taxation, thematically appropriate mass media campaigns, and appropriate smoking cessation support services. But there are as yet untried interventions with major potential. A key one is for a tighter regulatory framework that could rapidly shift the nicotine market towards pharmaceutical-grade nicotine (or smokeless tobacco products) and away from smoked tobacco
Aurora kinase A drives the evolution of resistance to third-generation EGFR inhibitors in lung cancer.
Although targeted therapies often elicit profound initial patient responses, these effects are transient due to residual disease leading to acquired resistance. How tumors transition between drug responsiveness, tolerance and resistance, especially in the absence of preexisting subclones, remains unclear. In epidermal growth factor receptor (EGFR)-mutant lung adenocarcinoma cells, we demonstrate that residual disease and acquired resistance in response to EGFR inhibitors requires Aurora kinase A (AURKA) activity. Nongenetic resistance through the activation of AURKA by its coactivator TPX2 emerges in response to chronic EGFR inhibition where it mitigates drug-induced apoptosis. Aurora kinase inhibitors suppress this adaptive survival program, increasing the magnitude and duration of EGFR inhibitor response in preclinical models. Treatment-induced activation of AURKA is associated with resistance to EGFR inhibitors in vitro, in vivo and in most individuals with EGFR-mutant lung adenocarcinoma. These findings delineate a molecular path whereby drug resistance emerges from drug-tolerant cells and unveils a synthetic lethal strategy for enhancing responses to EGFR inhibitors by suppressing AURKA-driven residual disease and acquired resistance
Ethical and regulatory implications of the COVID-19 pandemic for the medical devices industry and its representatives
The development and deployment of medical devices, along with most areas of healthcare, has been signifcantly impacted by the COVID-19 pandemic. This has had variable ethical implications, two of which we will focus on here. First, medical device regulations have been rapidly amended to expedite approvals of devices ranging from face masks to ventilators. Although some regulators have issued cessation dates, there is inadequate discussion of trig‑ gers for exiting these crisis standards, and evidence that this may not be feasible. Given the relatively low evidence standards currently required for regulatory approval of devices, this further indefnite reduction in standards raises serious ethical issues. Second, the pandemic has disrupted the usual operations of device representatives in hospi‑ tals, providing an opportunity to examine and refne this potentially ethically problematic practice. In this paper we explain and critically analyse the ethical implications of these two pandemic-related impacts on medical devices and propose suggestions for their management. These include an endpoint for pandemic-related adjustments to device regulation or a mechanism for continued refnement over time, together with a review of device research conducted under crisis conditions, support for the removal and replacement of emergency approved devices, and a review of device representative credentialling.Brette Blakely, Wendy Rogers, Jane Johnson, Quinn Grundy, Katrina Hutchison, Robyn Clay, Williams, Bernadette Richards, and Guy Madder
Plasma Deposited Diamond-Like Carbon Films for Large Neutralarrays
To understand how large systems of neurons communicate, we need to develop methods for growing patterned networks of large numbers of neurons. We have found that diamond-like carbon thin films formed by energetic deposition from a filtered vacuum arc carbon plasma can serve as ''neuron friendly'' substrates for the growth of large neural arrays. Lithographic masks can be used to form patterns of diamond-like carbon, and regions of selective neuronal attachment can form patterned neural arrays. In the work described here, we used glass microscope slides as substrates on which diamond-like carbon was deposited. PC-12 rat neurons were then cultured on the treated substrates and cell growth monitored. Neuron growth showed excellent contrast, with prolific growth on the treated surfaces and very low growth on the untreated surfaces. Here we describe the vacuum arc plasma deposition technique employed, and summarize results demonstrating that the approach can be used to form large patterns of neurons
Carbon nanotube substrates enhance SARS-CoV-2 spike protein ion yields in matrix assisted laser desorption-ionization mass spectrometry
Nanostructured surfaces enhance ion yields in matrix assisted laser
desorption-ionization mass spectrometry (MALDI-MS). The spike protein complex,
S1, is one fingerprint signature of Sars-CoV-2 with a mass of 75 kDa. Here, we
show that MALDI-MS yields of Sars-CoV-2 spike protein ions in the 100 kDa range
are enhanced 50-fold when the matrix-analyte solution is placed on substrates
that are coated with a dense forest of multi-walled carbon nanotubes, compared
to yields from uncoated substrates. Nanostructured substrates can support the
development of mass spectrometry techniques for sensitive pathogen detection
and environmental monitoring
Master planned estates : parish or panacea?
Master planned estates in Australia emerge from two major directions: one aims to address the inadequacies of 1970s suburbanisation and the other comes from governments and developers seeking to realise alternatives. The very idea of master planning has a longer history, one that arguably dates back to 19th-century Utopian Socialism and Baron Haussmann\u27s redesign of Paris, which involved a large-scale, comprehensive alternative vision realised by a sanctioned authority. Master planning thereby partakes of both utopianism and authoritarianism. These associations have infused the discussion and construction of Australian master planned estates rendering them both pariah and panacea. But research and my own experience suggests that they are far more panaceas than pariahs
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