Spiciness

We define and present algorithms for spiciness, which is an oceanographic variable whose isopycnal variations reflect isopycnal water-mass contrasts in density units. Discussion of spiciness in the oceanographic literature has often concentrated on its supposed orthogonality to isopycnals on the salinity-temperature diagram and how this orthogonal nature means that spiciness is a “passive” thermodynamic variable. Here we show that this “orthogonal” property is devoid of physical meaning. Moreover, it is emphasized that the notion of “orthogonality” on the salinity-temperature diagram does not give rise to a passive thermodynamic variable. Rather, the passive nature of variations of any thermodynamic variable is gained by evaluating those variations along isopycnals so that, for example, the isopycnal variations of both Absolute Salinity and Conservative Temperature are passive. The advantage of using isopycnal variations of our definition of spiciness is that this measures the passive spatial variations of water-mass properties in density units. The spiciness variables presented here have been derived using the equation of state from the International Thermodynamic Equation of Seawater – 2010

Ultrafast harmonic mode-locking of monolithic compound-cavity laser diodes incorporating photonic-bandgap reflectors

We present the first demonstration of reproducible harmonic mode-locked operation from a novel design of monolithic semiconductor laser comprising a compound cavity formed by a 1-D photonic-bandgap (PBG) mirror. Mode-locking (ML) is achieved at a harmonic of the fundamental round-trip frequency with pulse repetition rates from 131 GHz up to a record high frequency of 2.1 THz. The devices are fabricated from GaAs-Al-GaAs material emitting at a wavelength of 860 nm and incorporate two gain sections with an etched PBG reflector between them, and a saturable absorber section. Autocorrelation studies are reported which allow the device behavior for different ML frequencies, compound cavity ratios, and type and number of intra-cavity reflectors to be analyzed. The highly reflective PBG microstructures are shown to be essential for subharmonic-free ML operation of the high-frequency devices. We have also demonstrated that the single PBG reflector can be replaced by two separate features with lower optical loss. These lasers may find applications in terahertz; imaging, medicine, ultrafast optical links, and atmospheric sensing

Lifetimes of Shockley electrons and holes at the Cu(111) surface

A theoretical many-body analysis is presented of the electron-electron inelastic lifetimes of Shockley electrons and holes at the (111) surface of Cu. For a description of the decay of Shockley states both below and above the Fermi level, single-particle wave functions have been obtained by solving the Schr\"odinger equation with the use of an approximate one-dimensional pseudopotential fitted to reproduce the correct bulk energy bands and surface-state dispersion. A comparison with previous calculations and experiment indicates that inelastic lifetimes are very sensitive to the actual shape of the surface-state single-particle orbitals beyond the $\bar\Gamma$ (${\bf k}_\parallel=0$) point, which controls the coupling between the Shockley electrons and holes.Comment: 4 pages, 3 figures, to appear in Phys. Rev.

Parenteral antibiotics at home

Giving parenteral antibiotics to patients at home compared to in hospital presents unique challenges

Does the nonlinearity of the equation of state impose an upper bound on the buoyancy frequency?

Mixing in the ocean is usually accompanied by a net reduction in volume caused by the nonlinear nature of the equation of state. This contraction-on-mixing at a certain depth implies that the whole water column above this depth slumps a little and so suffers a reduction in gravitational potential energy. Under certain circumstances the gravitational potential energy of the entire water column can decrease as a consequence of mixing activity at a certain depth. We examine Fofonoff\u27s hypothesis that in these circumstances the net reduction of gravitational potential energy of the whole water column causes a local increase in the turbulent mixing activity at the location of the original mixing. Fofonoff proposed that this increased local mixing diffuses the local property gradients until the criterion for positive feedback is no longer satisfied, so providing an upper bound for the vertical stratification in the ocean. Bearing in mind the relatively inefficient nature of turbulent mixing at causing diapycnal fluxes (the majority of the turbulent kinetic energy goes directly into internal energy), we find that the criterion for positive feedback is a factor of approximately seven more difficult to achieve than has been realized to date. An examination of oceanic data shows that while Fofonoff\u27s original criterion for positive feedback is often exceeded, the more appropriate criterion is almost never approached. The positive feedback hypothesis assumes that the reduction in the gravitational potential energy of the whole water column appears at the location of the original mixing as an increase in the turbulent mixing activity. We show that this very focused oceanic response is extremely difficult to justify. For example there is no such feedback in a strictly one-dimensional water column; rather all of the reduction in gravitational potential energy appears as an increase in internal energy at the depth of the original mixing and there is no possibility of any positive feedback to increase the turbulent mixing. As the positive feedback hypothesis is lacking a convincing theoretical basis and is not supported by oceanic data, we do not believe that it acts as an effective upper bound on oceanic stratification

Patient choice at the point of GP referral: Department of Health

1 The Department of Health has a Public Service Agreement target to ensure that by the end of 2005 every hospital appointment in the National Health Service in England (the NHS) will be booked for the convenience of the patient, making it easier for patients and their General Practitioners (GPs) to choose the hospital and consultant that best meets their need. The Department aims to provide patients with the opportunity to choose between four to five healthcare providers for elective hospital treatment by December 2005. In consultation with their GP, patients should be able to choose, from a menu of NHS and independent sector healthcare providers, their preferred location for treatment. Patients should also be able to book the time and date of their initial outpatient appointment within 24 hours of the decision to refer the patient for treatment. This target will apply to around 9.4 million patients referred for hospital treatment by their GP each year, around four per cent of the total estimated 241 million GP consultations. 2 Choice at referral can contribute to a more patientfocused health service, bringing benefits to both patients and the NHS. But providing such a choice will not happen by accident. There are a number of dependencies and interactions with other policies that need to be managed. Information Technology (IT) systems need to be developed and modified and significant cultural, organisational and behavioural changes will need to be made by patients, NHS organisations and staff. 3 This report examines whether the Department is on track to deliver choice at the point of referral successfully by the target date of December 2005. Our work has found that: a Progress has been made towards delivering choice at referral through establishing the required organisational infrastructure, commissioning new IT systems and modifications to existing ones, and providing support for the NHS organisations that will deliver it. b The engagement of GPs is currently low and is a key risk which the Department must address to deliver choice successfully. The Department plans to address this risk through a campaign to inform and engage GPs during 2005 and it will need to monitor carefully the progress of this campaign. c Choice at referral will be delivered most efficiently and effectively through electronic booking (e-booking, also known as Choose and Book), in which the Electronic Booking Service, commissioned by the Department’s National Programme for IT (NPfIT), is linked to upgraded or new computer systems in hospitals and GPs’ surgeries. However, e-booking will not be universally available by December 2005. Until e-booking is fully adopted choice will have to be provided in other, less efficient, ways. d Parts of the NHS still have much to do if they are to deliver choice. A significant minority of Primary Care Trusts do not yet have adequate plans in place to manage the introduction of choice and some may struggle to manage the required new commissioning arrangements. 4 Our more detailed findings are as follows. Progress has been made towards delivering choice at referral 5 The Department believes that choice is affordable. Additional annual infrastructure and transaction costs are estimated to be £122 million – or 1.4 per cent of the current total expenditure on elective care. The main aim of introducing choice is to improve services for patients, but it should lead to increased efficiencies in primary and secondary care services worth an estimated £71 million, off-setting some of these costs. 6 It is essential that choice is supported by other elements of system reform including e-booking, payment by results, commissioning and appropriate capacity. Modelling exercises have shown that the system reforms should work in harmony with one another. Payment by results should enable the transfer of funding to follow the patient and there should be sufficient capacity across the system to enable choice to be effective. 7 Much of the organisational infrastructure that is required for choice is in place and there is clear accountability for the delivery of the programme. To strengthen detailed national programme management arrangements the Department created, on 22 December 2004, a new post of National Implementation Director for Choose and Book, with effect from 10 January 2005. The new Director will be responsible for overseeing the implementation of choice within the NHS whilst the National Programme for IT Group Programme Director for Choose and Book will continue to be responsible for Choose and Book technology development and deployment, patient access and Choose and Book contract management. 8 The Department has provided different types of support to the NHS – for example, ten pilot schemes have been run to test the policy in practice. It has set up a system for periodically measuring progress and used this to establish the position at the end of October 2004, creating a baseline against which to monitor future progress. 9 Research has identified what information patients will want to base their choices on, and the Department is seeking to provide this. While it is unlikely that full information will be available for December 2005, the majority of those aspects identified by patients as being the most important, such as waiting times and basic access information, will be in place. The Department plans to increase the information available over time. The key risk to the delivery of choice is the engagement of GPs 10 Choice cannot be delivered without support from GPs but our survey of GPs found that around half of GPs know very little about it and 61 per cent feel either very negative or a little negative. GPs’ concerns include practice capacity, workload, consultation length and fears that existing health inequalities will be exacerbated. The Department has deliberately held back its main effort to inform and engage GPs about choice until it has had a working e-booking system to show GPs, but it intends to mount a campaign to inform and engage GPs during 2005. Until e-booking is fully adopted choice will be supported by other mechanisms 11 The Department has commissioned Atos Origin to develop a national system for e-booking, which will be linked to upgraded or new Patient Administration Systems in hospitals and IT systems in GPs’ surgeries to provide an overall service known as e-booking. The National Programme for IT has planned the roll out of e-booking on an incremental basis to minimise risk, and to link it by the end of 2005 to some 60 to 70 per cent of hospital systems and GP practices. 12 E-booking is the most effective and efficient way of delivering the Department’s plans for choice, and alternative booking mechanisms offer poorer value for money. Atos Origin has delivered a functioning system and the first booking using e-booking was made in July 2004. However the roll-out of e-booking has been slower than planned and at the end of December 2004 only 63 bookings had been made. Problems have included the reluctance of users to work with an unreliable end-to-end system, limited progress in linking to GP and hospital systems, and the limited number of GPs willing to use the system. 13 The Department believes that new releases of software have addressed the reliability of the whole end-to-end system and that having a fully operational system will encourage GPs to engage with e-booking. The roll-out of changes to hospital systems to allow them to link to e-booking is gathering pace and four types of GP systems can now link to e-booking, although the largest supplier has not yet agreed an implementation plan. A combined team of Departmental and NHS personnel are working with the three main existing GP system suppliers to agree a national deployment schedule. This work should be completed by February 2005, along with a nationally negotiated commercial arrangement. The Department is also developing and trialling contingency plans against further delays, as well as alternatives to the fully integrated Choose and Book solution. Parts of the NHS still have much to do 14 Programme management arrangements in the NHS are incomplete. While most Primary Care Trusts expect to be able to deliver the choice target, there is variability in their overall performance. As many as a quarter of Primary Care Trusts currently forecast that they will not deliver the choice targets. In addition, some Primary Care Trusts may struggle to manage the new commissioning arrangements and two-thirds have yet to commission the required number of providers. The department is developing a framework of support to assist trusts to overcome these obstacles. 15 The Department needs urgently to address the low level of GP support for their plans for implementing choice at referral, and should: I Press on urgently with its plans for informing GPs about the implementation of choice at referral and its impact on GPs and patients. II Monitor the views of GPs, for example by a regular survey, repeating key questions from our own survey, to assess the rate of progress being achieved towards the level of support needed to meet its target of full implementation by December 2005. III Consider whether further action is needed to secure the required level of GP support, once GPs are fully informed on what choice at referral involves. 16 The Department should also: IV Complete its planned benefits realisation plan for choice at referral by the summer of 2005, along with a monitoring mechanism and quantified targets. V Keep under regular and close review the progress of its planned implementation of choice through implementing e-booking and consider the scope for accelerating the roll-out of e-booking to make it available everywhere by December 2005. VI If it becomes clear that it is not possible to deliver e-booking everywhere by December 2005, the Department should: a monitor closely the development of the interim solutions to ensure that they meet their delivery dates; and b ensure that the implementation of interim solutions does not detract from the priority of bringing in fully integrated e-booking systems as soon as possible. VII Establish an evaluation framework for Primary Care Trust commissioning to assist Strategic Health Authorities in assessing the capacity and skills of Primary Care Trusts in this area and securing improvements in capacity and skills where necessary

Researching the Aftermath of Slavery in Mainland East Africa: Methodological, Ethical, and Practical Challenges

This article examines ethical, practical, and methodological challenges in researching the aftermath of slavery in continental East Africa away from the coastal plantation belt. Interest in post-slavery there is recent and inspired by the apparent contrast with West Africa, where the issue is much more salient. The article explains this silence by highlighting politically-motivated avoidance of the issue in colonial sources and the preference of post-colonial historians for ‘useful’ pasts. Further, it questions the balance of successful integration and continuing marginalization reflected in the apparent obsolescence of slavery. It argues that tracing the trajectories of ex-slaves requires attention to all forms of social inequality and dependency, to the potential status implications for informants of speaking about slavery, and to the variety of terms and fields of meaning relevant to freedom, unfreedom and dependency. Recent research in this vein shows that slave antecedents remain a matter of aibu, shame, and that ex-slaves’ disappearance as a social category took lifelong efforts on their part. While the social valence of slave antecedents is relatively limited in mainland East Africa, slavery remains a problematic and painful heritage that demands great circumspection by researchers

Curating media learning: Towards a porous expertise

This article combines research results from a range of projects with two consistent themes. Firstly, we explore the potential for curation to offer a productive metaphor for the convergence of digital media learning across and between home / lifeworld and formal educational / systemworld spaces – or between the public and private spheres. Secondly, we draw conclusions from these projects to argue that the acceptance of transmedia literacy practices as a site for rich educational work – in media education and related areas – can only succeed if matched by a convergence of a more porous educator–student expertise