2,391 research outputs found
Failing to respond to health promotion imperatives could scupper or hamper National Health Insurance efforts
Towards run-time monitoring of web services conformance to business-level agreements
Web service behaviour is currently specified in a mixture of ways, often using methods that are only partially complete. These range from static functional specifications, based on interfaces in WSDL and preconditions in RIF, to business process simulations using executable process-based models such as BPEL, to detailed quality of service (QoS) agreements laid down in a service level agreement (SLA). This paper recognises that something similar to a SLA is required at the higher business level to govern the contract between service producers, brokers and consumers. We call this a business level agreement (BLA) and within this framework, seek to unify disparate aspects of functional specification, QoS and run-time verification. We propose that the method for validating a web service with respect to its advertised BLA should be based on run-time service monitoring. This is a position paper towards defining these goals
Tripartite interactions between two phase qubits and a resonant cavity
The creation and manipulation of multipartite entangled states is important
for advancements in quantum computation and communication, and for testing our
fundamental understanding of quantum mechanics and precision measurements.
Multipartite entanglement has been achieved by use of various forms of quantum
bits (qubits), such as trapped ions, photons, and atoms passing through
microwave cavities. Quantum systems based on superconducting circuits have been
used to control pair-wise interactions of qubits, either directly, through a
quantum bus, or via controllable coupling. Here, we describe the first
demonstration of coherent interactions of three directly coupled
superconducting quantum systems, two phase qubits and a resonant cavity. We
introduce a simple Bloch-sphere-like representation to help one visualize the
unitary evolution of this tripartite system as it shares a single microwave
photon. With careful control and timing of the initial conditions, this leads
to a protocol for creating a rich variety of entangled states. Experimentally,
we provide evidence for the deterministic evolution from a simple product
state, through a tripartite W-state, into a bipartite Bell-state. These
experiments are another step towards deterministically generating multipartite
entanglement in superconducting systems with more than two qubits
Decoherence, Autler-Townes effect, and dark states in two-tone driving of a three-level superconducting system
We present a detailed theoretical analysis of a multi-level quantum system
coupled to two radiation fields and subject to decoherence. We concentrate on
an effect known from quantum optics as the Autler-Townes splitting, which has
been recently demonstrated experimentally [M. A. Sillanpaa et al., Phys. Rev.
Lett. 103, 193601 (2009)] in a superconducting phase qubit. In the three-level
approximation, we derive analytical solutions and describe how they can be used
to extract the decoherence rates and to account for the measurement data.
Better agreement with the experiment can be obtained by extending this model to
five levels. Finally, we investigate the stationary states created in the
experiment and show that their structure is close to that of dark states.Comment: 16 pages, 8 figure
Circuit QED scheme for realization of the Lipkin-Meshkov-Glick model
We propose a scheme in which the Lipkin-Meshkov-Glick model is realized
within a circuit QED system. An array of N superconducting qubits interacts
with a driven cavity mode. In the dispersive regime, the cavity mode is
adiabatically eliminated generating an effective model for the qubits alone.
The characteristic long-range order of the Lipkin-Meshkov-Glick model is here
mediated by the cavity field. For a closed qubit system, the inherent second
order phase transition of the qubits is reflected in the intensity of the
output cavity field. In the broken symmetry phase, the many-body ground state
is highly entangled. Relaxation of the qubits is analyzed within a mean-field
treatment. The second order phase transition is lost, while new bistable
regimes occur.Comment: 5 pages, 2 figure
Managing Patients With Heart Failure: A Qualitative Study of Multidisciplinary Teams With Specialist Heart Failure Nurses
PURPOSE The purpose of this study was to explore the perceptions and experiences of health care clinicians working in multidisciplinary teams that include specialist heart failure nurses when caring for the management of heart failure patients.
METHODS We used a qualitative in-depth interview study nested in a broader ethnographic study of unplanned admissions in heart failure patients (HoldFAST). We interviewed 24 health care clinicians across primary, secondary, and community care in 3 locations in the Midlands, South Central, and South West of England.
RESULTS Within a framework of the role and contribution of the heart failure specialist nurse, our study identified 2 thematic areas that the clinicians agreed still represent particular challenges when working with heart failure patients. The first was communication with patients, in particular explaining the diagnosis and helping patients to understand the condition. The participants recognized that such communication was most effective when they had a long-term relationship with patients and families and that the specialist nurse played an important part in achieving this relationship. The second was communication within the team. Multidisciplinary input was especially needed because of the complexity of many patients and issues around medications, and the participants believed the specialist nurse may facilitate team communication. CONCLUSIONS The study highlights the role of specialist heart failure nurses in delivering education tailored to patients and facilitating better liaison among all clinicians, particularly when dealing with the management of comorbidities and drug regimens. The way in which specialist nurses were able to be caseworkers for their patients was perceived as a method of ensuring coordination and continuity of care
Optically Selected BL Lacertae Candidates from the Sloan Digital Sky Survey Data Release Seven
We present a sample of 723 optically selected BL Lac candidates from the SDSS
DR7 spectroscopic database encompassing 8250 deg^2 of sky; our sample
constitutes one of the largest uniform BL Lac samples yet derived. Each BL Lac
candidate has a high-quality SDSS spectrum from which we determine
spectroscopic redshifts for ~60% of the objects. Redshift lower limits are
estimated for the remaining objects utilizing the lack of host galaxy flux
contamination in their optical spectra; we find that objects lacking
spectroscopic redshifts are likely at systematically higher redshifts.
Approximately 80% of our BL Lac candidates match to a radio source in
FIRST/NVSS, and ~40% match to a ROSAT X-ray source. The homogeneous
multiwavelength coverage allows subdivision of the sample into 637 radio-loud
BL Lac candidates and 86 weak-featured radio-quiet objects. The radio-loud
objects broadly support the standard paradigm unifying BL Lac objects with
beamed radio galaxies. We propose that the majority of the radio-quiet objects
may be lower-redshift (z<2.2) analogs to high-redshift weak line quasars (i.e.,
AGN with unusually anemic broad emission line regions). These would constitute
the largest sample of such objects, being of similar size and complementary in
redshift to the samples of high-redshift weak line quasars previously
discovered by the SDSS. However, some fraction of the weak-featured radio-quiet
objects may instead populate a rare and extreme radio-weak tail of the much
larger radio-loud BL Lac population. Serendipitous discoveries of unusual white
dwarfs, high-redshift weak line quasars, and broad absorption line quasars with
extreme continuum dropoffs blueward of rest-frame 2800 Angstroms are also
briefly described.Comment: 24 pages, 14 figures, 8 tables. Accepted for publication in A
Coherent quantum state storage and transfer between two phase qubits via a resonant cavity
A network of quantum-mechanical systems showing long lived phase coherence of
its quantum states could be used for processing quantum information. As with
classical information processing, a quantum processor requires information bits
(qubits) that can be independently addressed and read out, long-term memory
elements to store arbitrary quantum states, and the ability to transfer quantum
information through a coherent communication bus accessible to a large number
of qubits. Superconducting qubits made with scalable microfabrication
techniques are a promising candidate for the realization of a large scale
quantum information processor. Although these systems have successfully passed
tests of coherent coupling for up to four qubits, communication of individual
quantum states between qubits via a quantum bus has not yet been demonstrated.
Here, we perform an experiment demonstrating the ability to coherently transfer
quantum states between two superconducting Josephson phase qubits through a
rudimentary quantum bus formed by a single, on chip, superconducting
transmission line resonant cavity of length 7 mm. After preparing an initial
quantum state with the first qubit, this quantum information is transferred and
stored as a nonclassical photon state of the resonant cavity, then retrieved at
a later time by the second qubit connected to the opposite end of the cavity.
Beyond simple communication, these results suggest that a high quality factor
superconducting cavity could also function as a long term memory element. The
basic architecture presented here is scalable, offering the possibility for the
coherent communication between a large number of superconducting qubits.Comment: 17 pages, 4 figures (to appear in Nature
“Knowledge I seek because culture doesn’t work anymore … It doesn’t work, death comes”: the experiences of third-generation female caregivers (gogos) in South Africa discussing sex, sexuality and HIV and AIDS with children in their care
Background
Sexual reproductive health communication between parents and children has been shown to promote safer sexual choices. In many South African households, third-generation female caregivers, often grandmothers or other older females, locally known as gogos, are primary caregivers of children due to parents being deceased or absent. Subsequently, the responsibility of talking about sex and related issues has shifted to these gogos. This study explored the experiences of gogos living in Alexandra, Johannesburg on talking about sex, sexuality and HIV and AIDS with children aged 10–18 years that are in their care.
Methods
Ten primary caregivers were purposively selected. Data were collected through in-depth individual interviews. Thematic analysis was performed and inductive codes and themes identified.
Results
All gogos selected found it difficult to discuss sex, sexuality and HIV and AIDS due to culture and traditional values impacting on personal experiences as well as generation and gender barriers. Perceived low self-efficacy due to low levels of knowledge and limited skills in speaking about sex, sexuality and HIV and AIDS also contributed to low levels of sexual reproductive health communication.
Conclusions
This study highlights the need for interventions that focus on improving gogos’ knowledge about sexual reproductive health in addition to providing them with the skills to talk about sex, sexuality and HIV and AIDS with children in their care
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