674 research outputs found

    The European Space Agency standard for space packet utilisation

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    This paper presents the ESA concept for the use of CCSDS defined Telemetry and Telecommand Packets at the application level. These Packets are used to monitor and control remotely a space born application. This concept is defined in a Packet Utilisation Standard (PUS) which should become applicable for all ESA missions using Packets. The production of this standard is under the responsibility of an ESA standardization group called 'COES'

    Temperature dependence of the electron spin g factor in GaAs

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    The temperature dependence of the electron spin gg factor in GaAs is investigated experimentally and theoretically. Experimentally, the gg factor was measured using time-resolved Faraday rotation due to Larmor precession of electron spins in the temperature range between 4.5 K and 190 K. The experiment shows an almost linear increase of the gg value with the temperature. This result is in good agreement with other measurements based on photoluminescence quantum beats and time-resolved Kerr rotation up to room temperature. The experimental data are described theoretically taking into account a diminishing fundamental energy gap in GaAs due to lattice thermal dilatation and nonparabolicity of the conduction band calculated using a five-level kp model. At higher temperatures electrons populate higher Landau levels and the average gg factor is obtained from a summation over many levels. A very good description of the experimental data is obtained indicating that the observed increase of the spin gg factor with the temperature is predominantly due to band's nonparabolicity.Comment: 6 pages 4 figure

    Patient Outcomes in Palliative Care - South Australia, July - December 2018

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    The Australian palliative care sector is a world leader in using routine clinical assessment information to guide patient centred care and measure patient and family outcomes. Providers of palliative care are commended for their commitment to excellence in delivering evidence-based, patient-centred care by using the routine Palliative Care Outcomes Collaboration (PCOC) assessment framework and contributing patient data toward national outcome measurement and benchmarking. PCOC acknowledges the dedication and willingness of clinicians to improve the care of patients, their families and caregivers. The information collected is not just data - it represents the real-life outcomes of over 40,000 Australians who die an expected death every year. While the focus of this report is on the most recent information relating to July to December 2018, results over the last three years are also presented to highlight achievements and improvement in outcomes. The most recent information corresponds to 23,333 patients, having 29,931 episodes of care and 70,135 palliative care phases from 127 services who provide palliative care in hospital / hospice or in the person\u27s home

    Public values for energy system change

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    In this paper we discuss the importance of framing the question of public acceptance of sustainable energy transitions in terms of values and a ‘whole-system’ lens. This assertion is based on findings arising from a major research project examining public values, attitudes and acceptability with regards to whole energy system change using a mixed-method (six deliberative workshops, n=68, and a nationally representative survey, n = 2441), interdisciplinary approach. Through the research we identify a set of social values associated with desirable energy futures in the UK, where the values represent identifiable cultural resources people draw on to guide their preference formation about particular aspects of energy system change. As such, we characterise public perspectives as being underpinned by six value clusters relating to efficiency and wastefulness, environment and nature, security and stability, social justice and fairness, autonomy and power, and processes and change. We argue that this ‘value system’ provides a basis for understanding core reasons for public acceptance or rejection of different energy system aspects and processes. We conclude that a focus on values that underpin more specific preferences for energy system change brings insights that could provide a basis for improved dialogue, more robust decision- making, and for anticipating likely points of conflict in energy transitions

    A profile of patients receiving palliative care in Western Australia for January - June 2019

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    The Palliative Care Outcomes Collaboration (PCOC) is a national program that aims to improve the quality and outcomes of palliative care in Australia. This is achieved via a standardised clinical language that supports a national data collection. This report provides a high level profile of 4,181 patients who received palliative care in Western Australia during July to December 2018 and had their pain, symptom, family / carer and psychological / spiritual issues assessed as part of routine clinical care

    Electron and hole states in quantum-dot quantum wells within a spherical 8-band model

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    In order to study heterostructures composed both of materials with strongly different parameters and of materials with narrow band gaps, we have developed an approach, which combines the spherical 8-band effective-mass Hamiltonian and the Burt's envelope function representation. Using this method, electron and hole states are calculated in CdS/HgS/CdS/H_2O and CdTe/HgTe/CdTe/H_2O quantum-dot quantum-well heterostructures. Radial components of the wave functions of the lowest S and P electron and hole states in typical quantum-dot quantum wells (QDQWs) are presented as a function of radius. The 6-band-hole components of the radial wave functions of an electron in the 8-band model have amplitudes comparable with the amplitude of the corresponding 2-band-electron component. This is a consequence of the coupling between the conduction and valence bands, which gives a strong nonparabolicity of the conduction band. At the same time, the 2-band-electron component of the radial wave functions of a hole in the 8-band model is small compared with the amplitudes of the corresponding 6-band-hole components. It is shown that in the CdS/HgS/CdS/H_2O QDQW holes in the lowest states are strongly localized in the well region (HgS). On the contrary, electrons in this QDQW and both electron and holes in the CdTe/HgTe/CdTe/H_2O QDQW are distributed through the entire dot. The importance of the developed theory for QDQWs is proven by the fact that in contrast to our rigorous 8-band model, there appear spurious states within the commonly used symmetrized 8-band model.Comment: 15 pages, 5 figures, E-mail addresses: [email protected], [email protected]

    Development of an eight-band theory for quantum-dot heterostructures

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    We derive a nonsymmetrized 8-band effective-mass Hamiltonian for quantum-dot heterostructures (QDHs) in Burt's envelope-function representation. The 8x8 radial Hamiltonian and the boundary conditions for the Schroedinger equation are obtained for spherical QDHs. Boundary conditions for symmetrized and nonsymmetrized radial Hamiltonians are compared with each other and with connection rules that are commonly used to match the wave functions found from the bulk kp Hamiltonians of two adjacent materials. Electron and hole energy spectra in three spherical QDHs: HgS/CdS, InAs/GaAs, and GaAs/AlAs are calculated as a function of the quantum dot radius within the approximate symmetrized and exact nonsymmetrized 8x8 models. The parameters of dissymmetry are shown to influence the energy levels and the wave functions of an electron and a hole and, consequently, the energies of both intraband and interband transitions.Comment: 36 pages, 10 figures, E-mail addresses: [email protected], [email protected]

    Public understanding in Great Britain of ocean acidification

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    Public engagement with climate change is critical for maintaining the impetus for meaningful emissions cuts. Ocean acidification (OA) is increasingly recognized by marine scientists as an important, but often overlooked, consequence of anthropogenic emissions1, 2. Although substantial evidence now exists concerning people’s understanding of climate change more generally3, very little is known about public perceptions of OA. Here, for the first time, we characterize in detail people’s understanding of this topic using survey data obtained in Great Britain (n = 2,501) during 2013 and 2014. We draw on theories of risk perception and consider how personal values influence attitudes towards OA. We find that public awareness of OA is very low compared to that of climate change, and was unaffected by the publication of the IPCC Fifth Assessment Report. Using an experimental approach, we show that providing basic information can heighten concern about OA, however, we find that attitude polarization along value-based lines may occur if the topic is explicitly associated with climate change. We discuss the implications of our findings for public engagement with OA, and the importance of learning lessons from communications research relating to climate change
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