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We construct families of translationally invariant, nearest-neighbour Hamiltonians on a 2D square lattice of d-level quantum systems (d constant), for which determining whether the system is gapped or gapless is an undecidable problem. This is true even with the promise that each Hamiltonian is either gapped or gapless in the strongest sense: it is promised to either have continuous spectrum above the ground state in the thermodynamic limit, or its spectral gap is lower-bounded by a constant. Moreover, this constant can be taken equal to the operator norm of the local operator that generates the Hamiltonian (the local interaction strength). The result still holds true if one restricts to arbitrarily small quantum perturbations of classical Hamiltonians. The proof combines a robustness analysis of Robinson’s aperiodic tiling, together with tools from quantum information theory: the quantum phase estimation algorithm and the history state technique mapping Quantum Turing Machines to Hamiltonians.
To assess experience, physical infrastructure, and capabilities of high-level isolation units (HLIUs) planning to participate in a 2018 global HLIU workshop hosted by the US National Emerging Special Pathogens Training and Education Center (NETEC).
Design:
An electronic survey elicited information on general HLIU organization, operating costs, staffing models, and infection control protocols of select global units.
Setting and participants:
The survey was distributed to site representatives of 22 HLIUs located in the United States, Europe, and Asia; 19 (86%) responded.
Methods:
Data were coded and analyzed using descriptive statistics.
Results:
The mean annual reported budget for the 19 responding units was US$484,615. Most (89%) had treated a suspected or confirmed case of a high-consequence infectious disease. Reported composition of trained teams included a broad range of clinical and nonclinical roles. The mean number of HLIU beds was 6.37 (median, 4; range, 2–20) for adults and 4.23 (median, 2; range, 1–10) for children; however, capacity was dependent on pathogen.
Conclusions:
Responding HLIUs represent some of the most experienced HLIUs in the world. Variation in reported unit infrastructure, capabilities, and procedures demonstrate the variety of HLIU approaches. A number of technical questions unique to HLIUs remain unanswered related to physical design, infection prevention and control procedures, and staffing and training. These key areas represent potential focal points for future evidence and practice guidelines. These data are important considerations for hospitals considering the design and development of HLIUs, and there is a need for continued global HLIU collaboration to define best practices.
The police murder of George Floyd in Minneapolis in May 2020 (just twenty-two city blocks from where I write) sparked global demonstrations and renewed long-standing struggles for change. At the southern border, government agents separated migrant children from their families and confined detainees in cages. Politicization of the pandemic made Asian Americans targets of violent racist outbursts. Indigenous women continued to suffer disproportionate harm with little attention to their plight. Finally, the right-wing insurrection at the U.S. Capitol in Washington, DC, in January 2021 marked the moment as especially volatile.
A major challenge of airway management is safe care of the patient with a narrowed airway. Small tracheal tubes offer one solution but pose a problem with ventilation. While inspiration may be achieved by use of a high-pressure source to overcome airway resistance, two problems exist: first, the high-pressure source demands technical excellence and exposes the patient to a high risk of barotrauma; second, conventional (passive) exhalation through a narrow tube is slow and cannot achieve a normal minute ventilation with a tracheal tube of less than 4.5 mm diameter. Recently technical developments have led to the ability to assist expiration and make it, like inspiration, an active process. This technology is used in the Ventrain manual ventilator, the 2.4 mm wide Tritube tracheal tube and the Evone automatic ventilator. These new devices and the applied technology enable solutions for safe management of the narrowed upper airway.
We implemented universal severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) testing of patients undergoing surgical procedures as a means to conserve personal protective equipment (PPE). The rate of asymptomatic coronavirus disease 2019 (COVID-19) was <0.5%, which suggests that early local public health interventions were successful. Although our protocol was resource intensive, it prevented exposures to healthcare team members.
The past decade has witnessed the advent of nanophotonics, where light–matter interaction is shaped, almost at will, with human-made designed nanostructures. However, the design process for these nanostructures has remained complex, often relying on the intuition and expertise of the designer, ultimately limiting the reach and penetration of this groundbreaking approach. Recently, there has been an increasing number of studies in applying machine learning techniques for the design of nanostructures. Most of these studies engage deep learning techniques, which entail training a deep neural network (DNN) to approximate the highly nonlinear function of the underlying physical process of the interaction between light and the nanostructures. At the end of the training, the DNN allows for on-demand design of nanostructures (i.e., the model can infer nanostructure geometries for desired light spectra). In this article, we review previous studies for designing nanostructures, including recent advances where a DNN is trained to generate a two-dimensional image of the designed nanostructure, which is not limited to a closed set of nanostructure shapes, and can be trained for the design of any geometry. This allows for better generalization, with higher applicability for real-world design problems.
The Single Ventricle Reconstruction Trial randomised neonates with hypoplastic left heart syndrome to a shunt strategy but otherwise retained standard of care. We aimed to describe centre-level practice variation at Fontan completion.
Methods:
Centre-level data are reported as median or median frequency across all centres and range of medians or frequencies across centres. Classification and regression tree analysis assessed the association of centre-level factors with length of stay and percentage of patients with prolonged pleural effusion (>7 days).
Results:
The median Fontan age (14 centres, 320 patients) was 3.1 years (range from 1.7 to 3.9), and the weight-for-age z-score was −0.56 (−1.35 + 0.44). Extra-cardiac Fontans were performed in 79% (4–100%) of patients at the 13 centres performing this procedure; lateral tunnels were performed in 32% (3–100%) at the 11 centres performing it. Deep hypothermic circulatory arrest (nine centres) ranged from 6 to 100%. Major complications occurred in 17% (7–33%). The length of stay was 9.5 days (9–12); 15% (6–33%) had prolonged pleural effusion. Centres with fewer patients (<6%) with prolonged pleural effusion and fewer (<41%) complications had a shorter length of stay (<10 days; sensitivity 1.0; specificity 0.71; area under the curve 0.96). Avoiding deep hypothermic circulatory arrest and higher weight-for-age z-score were associated with a lower percentage of patients with prolonged effusions (<9.5%; sensitivity 1.0; specificity = 0.86; area under the curve 0.98).
Conclusions:
Fontan perioperative practices varied widely among study centres. Strategies to decrease the duration of pleural effusion and minimise complications may decrease the length of stay. Further research regarding deep hypothermic circulatory arrest is needed to understand its association with prolonged pleural effusion.
Timely access to care services is crucial to support people with dementia and their family carers to live well. Carers of people with dementia (N = 390), recruited from eight countries, completed semi-structured interviews about their experiences of either accessing or not using formal care services over a 12-month period in the Access to Timely Formal Care (Actifcare) study. Participant responses were summarised using content analysis, categorised into clusters and frequencies were calculated. Less than half of the participants (42.3%) reported service use. Of those using services, 72.8 per cent reported timely access and of those not using services 67.2 per cent were satisfied with this situation. However, substantial minorities either reported access at the wrong time (27.2%), or feeling dissatisfied or mixed feelings about not accessing services (32.8%). Reasons for not using services included use not necessary yet, the carer provided support or refusal. Reasons given for using services included changes in the condition of the person with dementia, the service's ability to meet individual needs, not coping or the opportunity to access services arose. Facilitators and barriers to service use included whether participants experienced supportive professionals, the speed of the process, whether the general practitioner was helpful, participant's own proactive attitude and the quality of information received. To achieve timely support, simplified pathways to use of formal care services are needed.
We present the second data release (DR2) of the SkyMapper Southern Survey, a hemispheric survey carried out with the SkyMapper Telescope at Siding Spring Observatory in Australia, using six optical filters: u, v, g, r, i, z. DR2 is the first release to go beyond the
$\sim\!18$
mag (10
$\sigma$
) limit of the Shallow Survey released in the first data release (DR1), and includes portions of the sky at full survey depth that reach
$>\!21$
mag in g and r filters. The DR2 photometry has a precision as measured by internal reproducibility of 1% in u and v, and 0.7% in griz. More than 21 000
$\deg^2$
have data in some filters (at either Shallow or Main Survey depth) and over 7 000
$\deg^2$
have deep Main Survey coverage in all six filters. Finally, about 18 000
$\deg^2$
have Main Survey data in i and z filters, albeit not yet at full depth. The release contains over 120 000 images, as well as catalogues with over 500 million unique astrophysical objects and nearly 5 billion individual detections. It also contains cross-matches with a range of external catalogues such as Gaia DR2, Pan-STARRS1 DR1, GALEX GUVcat, 2MASS, and AllWISE, as well as spectroscopic surveys such as 2MRS, GALAH, 6dFGS, and 2dFLenS.
Concise and informative, this guide is for doctors preparing to specialise in stroke care and strokologists looking for rapid but in-depth scientific guidance on stroke management. This third edition is fully revised to ensure that medical professionals are completely up-to-date in this fast-moving field. Its practical and problem-based approach covers all important issues of prevention, diagnosis, and treatment of cerebrovascular diseases, and reviews epidemiology and risk assessment. This new edition features expanded sections on topics of stroke unit management, thrombolysis, neurointerventions, cognitive impairment, secondary prevention and rehabilitation, and includes new chapters on neurointensive care and small vessel disease. Comprehensive in its coverage, the textbook includes acute assessment, imaging and emergency interventions. The authors are renowned experts in their field and have been working together in a teaching faculty for the European Master in Stroke Medicine Programme, which is supported by the European Stroke Organisation and the World Stroke Organisation.