Computer aids and human second reading as interventions in screening mammography: two systematic reviews to compare effects on cancer detection and recall rate

Background: There are two competing methods for improving the accuracy of a radiologist interpreting screening mammograms: computer aids (CAD) or independent second reading. Methods: Bibliographic databases were searched for clinical trials. Meta-analyses estimated impacts of CAD and double reading on odds ratios for cancer detection and recall rates. Sub-group analyses considered double reading with arbitration. Results: Ten studies compared single reading with CAD to single reading. Seventeen compared double to single reading. Double reading increases cancer detection and recall rates. Double reading with arbitration increases detection rate (CI: 1.02-1.15) and decreases recall rate (CI: 0.92-0.96). CAD does not have a significant effect on cancer detection rate (CI: 0.96-1.13) and increases recall rate (95% CI: 1.09-1.12). However, there is considerable heterogeneity in the impact on recall rate in both sets of studies. Conclusion: The evidence that double reading with arbitration enhances screening is stronger than that for single reading with CAD

Physical implementations of quantum absorption refrigerators

Absorption refrigerators are autonomous thermal machines that harness the spontaneous flow of heat from a hot bath into the environment in order to perform cooling. Here we discuss quantum realizations of absorption refrigerators in two different settings: namely, cavity and circuit quantum electrodynamics. We first provide a unified description of these machines in terms of the concept of virtual temperature. Next, we describe the two different physical setups in detail and compare their properties and performance. We conclude with an outlook on future work and open questions in this field of research.Comment: Patrick P. Potts was formerly known as Patrick P. Hofe

Fundamental limits on low-temperature quantum thermometry with finite resolution

While the ability to measure low temperatures accurately in quantum systems is important in a wide range of experiments, the possibilities and the fundamental limits of quantum thermometry are not yet fully understood theoretically. Here we develop a general approach to low-temperature quantum thermometry, taking into account restrictions arising not only from the sample but also from the measurement process. We derive a fundamental bound on the minimal uncertainty for any temperature measurement that has a finite resolution. A similar bound can be obtained from the third law of thermodynamics. Moreover, we identify a mechanism enabling sub-exponential scaling, even in the regime of finite resolution. We illustrate this effect in the case of thermometry on a fermionic tight-binding chain with access to only two lattice sites, where we find a quadratic divergence of the uncertainty. We also give illustrative examples of ideal quantum gases and a square-lattice Ising model, highlighting the role of phase transitions.Comment: Published version. Main text: 12 pages, 5 figures; see also related work by K. Hovhannisyan and L. A. Correa at arXiv:1712.0308

On Holiday! Policy and provision for disabled children and their families

This summary describes some findings from the On Holiday! study, carried out by the Thomas Coram Research Unit between 2004 and 2006 and funded by DfES. The study investigated the experiences of disabled children and their families outside school time and especially during the school holidays. The study took an approach informed by a social model of disability, one which emphasises the social construction of disability, rather than impairment

A meta-narrative review of electronic patient records

This session comprises four papers that consider how systematic review methods may be developed in order to make the best use of complex evidence in education and health. The methods and approaches reflected upon in these papers are not drawn from a single research tradition, but share a common goal of broadening the methodological scope of systematic reviews and better understanding the utilisation of knowledge produced in this way. The first paper (Henry Potts) reports an ongoing review using a meta-narrative approach to make sense of the diverse sources of knowledge regarding electronic patient records. The review method has stressed the importance of understanding knowledge from within the research tradition in which it was produced; it is argued that this has important implications for the way that evidence is utilised in the policy making process. The second paper (Geoff Wong) reflects upon the experience of using an explicit realist approach in the synthesis of the evidence in Internet based learning. This realist synthesis offers a method of making sense of the highly heterogeneous and context dependent evidence which exists in this field thus enabling greater insights into what makes such educational interventions ‘work’. The third paper (Rod Sheaff) reports a review of the predominantly qualitative research literature on organisational structures and their impacts upon policy outcomes in health systems. A scoping study found 14389 relevant papers of which 1568 were selected for review. These studies were very variable in the amount and quality of the qualitative data, hence 'evidence', which they reported. The paper describes an attempt to adapt realist methods so as to synthesise such bodies of research in ways which take account of this variation in the strength of qualitative evidence. The fourth paper (Mark Pearson) draws upon the work of Donald Campbell and colleagues in order to gain a fuller understanding of how systematic reviews are utilised in the policy making process. It is argued that interpretive approaches to understanding policy making (such as rhetorical analysis) need to be tempered with a more nuanced understanding of research validity. The case is made that interpretive approaches not only can, but should, be melded with research validity to increase understanding of the policy making process

Certifying Non-Classical Behavior for Negative Keldysh Quasi-Probabilities

We introduce an experimental test for ruling out classical explanations for the statistics obtained when measuring arbitrary observables at arbitrary times using individual detectors. This test requires some trust in the measurements, represented by a few natural assumptions on the detectors. In quantum theory, the considered scenarios are well captured by von Neumann measurements. These can be described naturally in terms of the Keldysh quasi-probability distribution (KQPD), and the imprecision and backaction exerted by the measurement apparatus. We find that classical descriptions can be ruled out from measured data if and only if the KQPD exhibits negative values. We provide examples based on simulated data, considering the influence of a finite amount of statistics. In addition to providing an experimental tool for certifying non-classicality, our results bestow an operational meaning upon the non-classical nature of negative quasi-probability distributions such as the Wigner function and the full counting statistics.Comment: Published version. The author was previously known as Patrick P. Hofe

New critical frontiers for the Potts and percolation models

We obtain the critical threshold for a host of Potts and percolation models on lattices having a structure which permits a duality consideration. The consideration generalizes the recently obtained thresholds of Scullard and Ziff for bond and site percolation on the martini and related lattices to the Potts model and to other lattices.Comment: 9 pages, 5 figure

Pollination services in the UK: how important are honeybees?

Pollination services are known to provide substantial benefits to human populations and agriculture in particular. Although many species are known to provide pollination services, honeybees (Apis mellifera) are often assumed to provide the majority of these services to agriculture. Using data from a range of secondary sources, this study assesses the importance of insect pollinated crops at regional and national scales and investigates the capacity of honeybees to provide optimal pollination services to UK agriculture. The findings indicate that insect pollinated crops have become increasingly important in UK crop agriculture and, as of 2007, accounted for 20% of UK cropland and 19% of total farmgate crop value. Analysis of honeybee hive numbers indicates that current UK populations are only capable of supplying 34% of pollination service demands even under favourable assumptions, falling from 70% in 1984. In spite of this decline, insect pollinated crop yields have risen by an average of 54% since 1984, casting doubt on long held beliefs that honeybees provide the majority of pollination services. Future land use and crop production patterns may further increase the role of pollination services to UK agriculture, highlighting the importance of measures aimed at maintaining both wild and managed species

Carbon incorporation in ZnSe grown by metalorganic chemical vapor deposition

Carbon incorporation in ZnSe films grown by metalorganic chemical vapor deposition is reported. Secondary‐ion mass spectrometry measurements in ZnSe films grown from methylallylselenide and dimethylzinc show an enhanced carbon accumulation at the interface between ZnSe and GaAs. The carbon incorporation in the bulk ZnSe increases with the VI/II ratio and for a value of VI/II=3–4, the amount of incorporated carbon abruptly jumps to concentrations of 10^(21) cm^(−3), whereupon the films become polycrystalline. A new shallow peak I^C at 2.7920 eV dominates the near‐band‐edge low‐temperature photoluminescence spectra of all carbon‐contaminated ZnSe films. The intensity and linewidth of I^C increase with the VI/II ratio in a similar manner to the carbon concentration. This peak is proposed to be due to the radiative decay of excitons bound to a complex defect, which is associated with the presence of carbon in the films