Parallel remote state preparation for fully device-independent verifiable blind quantum computation

We introduce a device-independent two-prover scheme in which a classical verifier is able to use a simple untrusted quantum measurement device (the client device) to securely delegate a quantum computation to an untrusted quantum server. To do this, we construct a parallel self-testing protocol to perform device-independent remote state preparation of $n$ qubits and compose this with the unconditionally secure universal verifiable blind quantum computation (VBQC) scheme of J. F. Fitzsimons and E. Kashefi [Phys. Rev. A 96, 012303 (2017)]. Our self-test achieves a multitude of desirable properties for the application we consider, giving rise to practical and fully device-independent VBQC. It certifies parallel measurements of all cardinal and intercardinal directions in the $XY$-plane as well as the computational basis, uses few input questions (of size logarithmic in $n$ for the client and a constant number communicated to the server), and requires only single-qubit measurements to be performed by the client device.Comment: 55 pages, 3 figure

Practical parallel self-testing of Bell states via magic rectangles

Self-testing is a method to verify that one has a particular quantum state from purely classical statistics. For practical applications, such as device-independent delegated verifiable quantum computation, it is crucial that one self-tests multiple Bell states in parallel while keeping the quantum capabilities required of one side to a minimum. In this work, we use the $3 \times n$ magic rectangle games (generalizations of the magic square game) to obtain a self-test for $n$ Bell states where the one side needs only to measure single-qubit Pauli observables. The protocol requires small input sizes (constant for Alice and $O(\log n)$ bits for Bob) and is robust with robustness $O(n^{5/2} \sqrt{\varepsilon})$, where $\varepsilon$ is the closeness of the ideal (perfect) correlations to those observed. To achieve the desired self-test we introduce a one-side-local quantum strategy for the magic square game that wins with certainty, generalize this strategy to the family of $3 \times n$ magic rectangle games, and supplement these nonlocal games with extra check rounds (of single and pairs of observables).Comment: 29 pages, 6 figures; v3 minor corrections and changes in response to comment

Nonlocal games and their device-independent quantum applications

Device-independence is a property of certain protocols that allows one to ensure their proper execution given only classical interaction with devices and assuming the correctness of the laws of physics. This scenario describes the most general form of cryptographic security, in which no trust is placed in the hardware involved; indeed, one may even take it to have been prepared by an adversary. Many quantum tasks have been shown to admit device-independent protocols by augmentation with "nonlocal games". These are games in which noncommunicating parties jointly attempt to fulfil some conditions imposed by a referee. We introduce examples of such games and examine the optimal strategies of players who are allowed access to different possible shared resources, such as entangled quantum states. We then study their role in self-testing, private random number generation, and secure delegated quantum computation. Hardware imperfections are naturally incorporated in the device-independent scenario as adversarial, and we thus also perform noise robustness analysis where feasible. We first study a generalization of the Mermin–Peres magic square game to arbitrary rectangular dimensions. After exhibiting some general properties, these "magic rectangle" games are fully characterized in terms of their optimal win probabilities for quantum strategies. We find that for m×n magic rectangle games with dimensions m,n≥3, there are quantum strategies that win with certainty, while for dimensions 1×n quantum strategies do not outperform classical strategies. The final case of dimensions 2×n is richer, and we give upper and lower bounds that both outperform the classical strategies. As an initial usage scenario, we apply our findings to quantum certified randomness expansion to find noise tolerances and rates for all magic rectangle games. To do this, we use our previous results to obtain the winning probabilities of games with a distinguished input for which the devices give a deterministic outcome and follow the analysis of C. A. Miller and Y. Shi [SIAM J. Comput. 46, 1304 (2017)]. Self-testing is a method to verify that one has a particular quantum state from purely classical statistics. For practical applications, such as device-independent delegated verifiable quantum computation, it is crucial that one self-tests multiple Bell states in parallel while keeping the quantum capabilities required of one side to a minimum. We use our 3×n magic rectangle games to obtain a self-test for n Bell states where one side needs only to measure single-qubit Pauli observables. The protocol requires small input sizes [constant for Alice and O(log n) bits for Bob] and is robust with robustness O(n⁵/²√ε), where ε is the closeness of the ideal (perfect) correlations to those observed. To achieve the desired self-test, we introduce a one-side-local quantum strategy for the magic square game that wins with certainty, we generalize this strategy to the family of 3×n magic rectangle games, and we supplement these nonlocal games with extra check rounds (of single and pairs of observables). Finally, we introduce a device-independent two-prover scheme in which a classical verifier can use a simple untrusted quantum measurement device (the client device) to securely delegate a quantum computation to an untrusted quantum server. To do this, we construct a parallel self-testing protocol to perform device-independent remote state preparation of n qubits and compose this with the unconditionally secure universal verifiable blind quantum computation (VBQC) scheme of J. F. Fitzsimons and E. Kashefi [Phys. Rev. A 96, 012303 (2017)]. Our self-test achieves a multitude of desirable properties for the application we consider, giving rise to practical and fully device-independent VBQC. It certifies parallel measurements of all cardinal and intercardinal directions in the XY-plane as well as the computational basis, uses few input questions (of size logarithmic in n for the client and a constant number communicated to the server), and requires only single-qubit measurements to be performed by the client device

Preoperative Bowel Preparation Prior to Elective Bowel Resection or Ostomy Closure in the Pediatric Patient Population Has No Impact on Outcomes. A Prospective Randomized Study

The role of preoperative bowel prep in the pediatric surgical population is uncertain. We performed a randomized prospective study to evaluate noninferiority between the presence or absence of a preoperative bowel prep in elective pediatric bowel surgery on postoperative outcomes. Patients aged three months to 18 years were recruited and randomized to the bowel prep group or the no bowel prep group. Patients were evaluated in-hospital and at postoperative clinic visits. Thirty-two patients were recruited; 18 in the bowel prep group and 14 in the no bowel prep group. There was no statistical difference (P > 0.05) in complications between the groups. Complications were observed in five patients in each group (27.8% and 35.7%, respectively). In the bowel prep group, two (11.1%) had wound infection (vs three, 21.4%), 0 had an intra-abdominal abscess (vs one, 7.1%), one (5.6%) had sepsis (vs one, 7.1%), one (5.6%) had an anastomotic leak (vs 0), and three (16.7%) had a bowel obstruction (vs one, 7.1%). There were no extra-abdominal complications. There were no significant differences in complications between the two groups. Further research is warranted, but may require a multi-institutional trial to recruit sufficient numbers to make conclusions about the significance of the need for bowel prep

Potential impacts of general practitioners working in or alongside emergency departments in England: Initial qualitative findings from a national mixed-methods evaluation

Objectives To explore the potential impacts of introducing General Practitioners into Emergency Departments (GPED) from the perspectives of service leaders, health professionals and patients. These 'expectations of impact' can be used to generate hypotheses that will inform future implementations and evaluations of GPED. Design Qualitative study consisting of 228 semistructured interviews. Setting 10 acute National Health Service (NHS) hospitals and the wider healthcare system in England. Interviews were undertaken face to face or via telephone. Data were analysed thematically. Participants 124 health professionals and 94 patients and carers. 10 service leaders representing a range of national organisations and government departments across England (eg, NHS England and Department of Health) were also interviewed. Results A range of GPED models are being implemented across the NHS due to different interpretations of national policy and variation in local context. This has resulted in stakeholders and organisations interpreting the aims of GPED differently and anticipating a range of potential impacts. Participants expected GPED to affect the following areas: ED performance indicators; patient outcome and experience; service access; staffing and workforce experience; and resources. Across these 'domains of influence', arguments for positive, negative and no effect of GPED were proposed. Conclusions Evaluating whether GPED has been successful will be challenging. However, despite uncertainty surrounding the direction of effect, there was agreement across all stakeholder groups on the areas that GPED would influence. As a result, we propose eight domains of influence that will inform our subsequent mixed-methods evaluation of GPED

General practitioners and emergency departments (GPED) - Efficient models of care: A mixed-methods study protocol

© Author(s) (or their employer(s)) 2018. Re-use permitted under CC BY. Published by BMJ. Introduction Pressure continues to grow on emergency departments in the UK and throughout the world, with declining performance and adverse effects on patient outcome, safety and experience. One proposed solution is to locate general practitioners to work in or alongside the emergency department (GPED). Several GPED models have been introduced, however, evidence of effectiveness is weak. This study aims to evaluate the impact of GPED on patient care, the primary care and acute hospital team and the wider urgent care system. Methods and analysis The study will be divided into three work packages (WPs). WP-A; Mapping and Taxonomy: Mapping, description and classification of current models of GPED in all emergency departments in England and interviews with key informants to examine the hypotheses that underpin GPED. WP-B; Quantitative Analysis of National Data: Measurement of the effectiveness, costs and consequences of the GPED models identified in WP-A, compared with a no-GPED model, using retrospective analysis of Hospital Episode Statistics Data. WP-C; Case Studies: Detailed case studies of different GPED models using a mixture of qualitative and quantitative methods including: non-participant observation of clinical care, semistructured interviews with staff, patients and carers; workforce surveys with emergency department staff and analysis of available local routinely collected hospital data. Prospective case study sites will be identified by completing telephone interviews with sites awarded capital funding by the UK government to implement GPED initiatives. The study has a strong patient and public involvement group that has contributed to study design and materials, and which will be closely involved in data interpretation and dissemination. Ethics and dissemination The study has been approved by the National Health Service East Midlands - Leicester South Research Ethics Committee: 17/EM/0312. The results of the study will be disseminated through peer-reviewed journals, conferences and a planned programme of knowledge mobilisation

Do general practitioners working in or alongside the emergency department improve clinical outcomes or experience? A mixed-methods study

OBJECTIVES: To examine the effect of general practitioners (GPs) working in or alongside the emergency department (GPED) on patient outcomes and experience, and the associated impacts of implementation on the workforce. DESIGN: Mixed-methods study: interviews with service leaders and NHS managers; in-depth case studies (n=10) and retrospective observational analysis of routinely collected national data. We used normalisation process theory to map our findings to the theory's four main constructs of coherence, cognitive participation, collective action and reflexive monitoring. SETTING AND PARTICIPANTS: Data were collected from 64 EDs in England. Case site data included: non-participant observation of 142 clinical encounters; 467 semistructured interviews with policy-makers, service leaders, clinical staff, patients and carers. Retrospective observational analysis used routinely collected Hospital Episode Statistics alongside information on GPED service hours from 40 hospitals for which complete data were available. RESULTS: There was disagreement at individual, stakeholder and organisational levels regarding the purpose and potential impact of GPED (coherence). Participants criticised policy development and implementation, and staff engagement was hindered by tensions between ED and GP staff (cognitive participation). Patient 'streaming' processes, staffing and resource constraints influenced whether GPED became embedded in routine practice. Concerns that GPED may increase ED attendance influenced staff views. Our quantitative analysis showed no detectable impact on attendance (collective action). Stakeholders disagreed whether GPED was successful, due to variations in GPED model, site-specific patient mix and governance arrangements. Following statistical adjustment for multiple testing, we found no impact on: ED reattendances within 7 days, patients discharged within 4 hours of arrival, patients leaving the ED without being seen; inpatient admissions; non-urgent ED attendances and 30-day mortality (reflexive monitoring). CONCLUSIONS: We found a high degree of variability between hospital sites, but no overall evidence that GPED increases the efficient operation of EDs or improves clinical outcomes, patient or staff experience. TRIAL REGISTRATION NUMBER: ISCRTN5178022

General practitioners working in or alongside the emergency department : the GPED mixed-methods study

Background: Emergency care is facing a steadily rising demand. In response, hospitals have implemented new models of care that locate general practitioners in or alongside the emergency department. Objectives: We aimed to explore the effects of general practitioners working in or alongside the emergency department on patient care, the primary care and acute hospital team, and the wider system, as well as to determine the differential effects of different service models. Design: This was a mixed-methods study in three work packages. Work package A classified current models of general practitioners working in or alongside the emergency department in England. We interviewed national and local leaders, staff and patients to identify the hypotheses underpinning these services. Work package B used a retrospective analysis of routinely available data. Outcome measures included waiting times, admission rates, reattendances, mortality and the number of patient attendances. We explored potential cost savings. Work package C was a detailed mixed-methods case study in 10 sites. We collected and synthesised qualitative and quantitative data from non-participant observations, interviews and a workforce survey. Patients and the public were involved throughout the development, delivery and dissemination of the study. Results: High-level goals were shared between national policy-makers and local leads; however, there was disagreement about the anticipated effects. We identified eight domains of influence: performance against the 4-hour target, use of investigations, hospital admissions, patient outcome and experience, service access, workforce recruitment and retention, workforce behaviour and experience, and resource use. General practitioners working in or alongside the emergency department were associated with a very slight reduction in the rate of reattendance within 7 days; however, the clinical significance of this was judged to be negligible. For all other indicators, there was no effect on performance or outcomes. However, there was a substantial degree of heterogeneity in these findings. This is explained by the considerable variation observed in our case study sites, and the sensitivity of service implementation to local factors. The effects on the workforce were complex; they were often positive for emergency department doctors and general practitioners, but less so for nursing staff. The patient-streaming process generated stress and conflict for emergency department nurses and general practitioners. Patients and carers were understanding of general practitioners working in or alongside the emergency department. We found no evidence that staff concerns regarding the potential to create additional demand were justified. Any possible cost savings associated with reduced reattendances were heavily outweighed by the cost of the service. Limitations: The reliability of our data sources varied and we were unable to complete our quantitative analysis entirely as planned. Participation in interviews and at case study sites was voluntary. Conclusions: Service implementation was highly subject to local context and micro-level influences. Key success factors were interprofessional working, staffing and training, streaming, and infrastructure and support

Neuropathology of wild-type and nef-attenuated T cell tropic simian immunodeficiency virus (SIVmac32H) and macrophage tropic neurovirulent SIVmac17E-Fr in cynomolgus macaques

The neuropathology of simian immunodeficiency (SIV) infection in cynomolgus macaques (Macaca fascicularis) was investigated following infection with either T cell tropic SIVmacJ5, SIVmacC8 or macrophage tropic SIVmac17E-Fr. Formalin fixed, paraffin embedded brain tissue sections were analysed using a combination of in situ techniques. Macaques infected with either wild-type SIVmacJ5 or neurovirulent SIVmac17E-Fr showed evidence of neuronal dephosphorylation, loss of oligodendrocyte and CCR5 staining, lack of microglial MHC II expression, infiltration by CD4+ and CD8+ T cells and mild astrocytosis. SIVmacJ5-infected animals exhibited activation of microglia whilst those infected with SIVmac17E-Fr demonstrated a loss of microglia staining. These results are suggestive of impaired central nervous system (CNS) physiology. Furthermore, infiltration by T cells into the brain parenchyma indicated disruption of the blood brain barrier (BBB). Animals infected with the Δnef-attenuated SIVmacC8 showed microglial activation and astrogliosis indicative of an inflammatory response, lack of MHC II and CCR5 staining and infiltration by CD8+ T cells. These results demonstrate that the SIV infection of cynomolgus macaque can be used as a model to replicate the range of CNS pathologies observed following HIV infection of humans and to investigate the pathogenesis of HIV associated neuropathology