Digitized adiabatic quantum computing with a superconducting circuit.

Quantum mechanics can help to solve complex problems in physics and chemistry, provided they can be programmed in a physical device. In adiabatic quantum computing, a system is slowly evolved from the ground state of a simple initial Hamiltonian to a final Hamiltonian that encodes a computational problem. The appeal of this approach lies in the combination of simplicity and generality; in principle, any problem can be encoded. In practice, applications are restricted by limited connectivity, available interactions and noise. A complementary approach is digital quantum computing, which enables the construction of arbitrary interactions and is compatible with error correction, but uses quantum circuit algorithms that are problem-specific. Here we combine the advantages of both approaches by implementing digitized adiabatic quantum computing in a superconducting system. We tomographically probe the system during the digitized evolution and explore the scaling of errors with system size. We then let the full system find the solution to random instances of the one-dimensional Ising problem as well as problem Hamiltonians that involve more complex interactions. This digital quantum simulation of the adiabatic algorithm consists of up to nine qubits and up to 1,000 quantum logic gates. The demonstration of digitized adiabatic quantum computing in the solid state opens a path to synthesizing long-range correlations and solving complex computational problems. When combined with fault-tolerance, our approach becomes a general-purpose algorithm that is scalable.

[Gestational diabetes mellitus : prelude of risks not to be misunderstood]. / Le diabète gestationnel. Prélude de risques à ne pas méconnaître.

Gestational diabetes mellitus is a common complication in pregnant women. It is diagnosed between the 24th and 28th last menstrual period thanks to an oral glucose tolerance test with 75 g of glucose. Although blood glucose levels usually return to normal after childbirth, it can lead to some medium- and long-term complications, including cardiovascular, metabolic and renal complications. Early detection of various risk factors related to these complications would avoid some negative consequences for women with background of gestational diabetes.

Le diabète gestationnel est une complication fréquente chez la femme enceinte. Il est diagnostiqué entre la 24ème et la 28ème semaine d'aménorrhée grâce à la réalisation d'une hyperglycémie provoquée par voie orale avec 75 g de glucose. Même si la glycémie se normalise après l'accouchement dans la plupart des cas, un antécédent de diabète gestationnel peut entraîner différentes complications à moyen et long termes, notamment sur le plan cardiovasculaire, métabolique et rénal. Un dépistage précoce des différents facteurs de risque liés à ces complications permettrait d'éviter certaines conséquences néfastes pour les femmes après un diabète gestationnel.

[The value of human resources: experience of critical care nurses during the COVID-19 epidemic]. / El valor del recurso humano: experiencia de profesionales enfermeros de cuidados críticos durante la pandemia por COVID-19.

The COVID-19 pandemic has caused an unprecedented health crisis. Pressure on the National Health System has created unique demand particularly in certain services and care units like the critical care units. Objective: To learn about the experience of nurses in caring for people with coronavirus in critical care units. Method: A qualitative phenomenological study that constitutes the second phase of a mixed methodology project. We conducted interviews with 17 nurses caring for patients affected by COVID-19 in critical care units. The interviews were audio-recorded, transcribed, and analysed using thematic discourse analysis. Results: This article shows the findings around the theme "the value of human resources" which is nuanced through sub-themes "it's not the beds, it's the expert staff", "shouldering the patient's burden", and suffering because "they have not cared well". Discussion: Expert nurses have emerged as leading professionals in the care of the critical patient during the COVID-19 pandemic. This leadership is executed from a profile framed in an inclusive philosophy where wisdom, agility and intuition are the key elements underpinning problem identification and solving in a creative way, while adapting to the needs of the patient and healthcare team as they emerge. Conclusions: Expert nurses have played an advanced role in the management of care and human resources by exercising effective leadership in the clinical setting. Care has been hampered due to the crisis, which causes nurses moral distress because they have been unable to meet standards of quality and excellence in care.

State preservation by repetitive error detection in a superconducting quantum circuit.

Quantum computing becomes viable when a quantum state can be protected from environment-induced error. If quantum bits (qubits) are sufficiently reliable, errors are sparse and quantum error correction (QEC) is capable of identifying and correcting them. Adding more qubits improves the preservation of states by guaranteeing that increasingly larger clusters of errors will not cause logical failure-a key requirement for large-scale systems. Using QEC to extend the qubit lifetime remains one of the outstanding experimental challenges in quantum computing. Here we report the protection of classical states from environmental bit-flip errors and demonstrate the suppression of these errors with increasing system size. We use a linear array of nine qubits, which is a natural step towards the two-dimensional surface code QEC scheme, and track errors as they occur by repeatedly performing projective quantum non-demolition parity measurements. Relative to a single physical qubit, we reduce the failure rate in retrieving an input state by a factor of 2.7 when using five of our nine qubits and by a factor of 8.5 when using all nine qubits after eight cycles. Additionally, we tomographically verify preservation of the non-classical Greenberger-Horne-Zeilinger state. The successful suppression of environment-induced errors will motivate further research into the many challenges associated with building a large-scale superconducting quantum computer.

Demonstrating a Continuous Set of Two-Qubit Gates for Near-Term Quantum Algorithms.

Quantum algorithms offer a dramatic speedup for computational problems in material science and chemistry. However, any near-term realizations of these algorithms will need to be optimized to fit within the finite resources offered by existing noisy hardware. Here, taking advantage of the adjustable coupling of gmon qubits, we demonstrate a continuous two-qubit gate set that can provide a threefold reduction in circuit depth as compared to a standard decomposition. We implement two gate families: an imaginary swap-like (iSWAP-like) gate to attain an arbitrary swap angle, θ, and a controlled-phase gate that generates an arbitrary conditional phase, ϕ. Using one of each of these gates, we can perform an arbitrary two-qubit gate within the excitation-preserving subspace allowing for a complete implementation of the so-called Fermionic simulation (fSim) gate set. We benchmark the fidelity of the iSWAP-like and controlled-phase gate families as well as 525 other fSim gates spread evenly across the entire fSim(θ,ϕ) parameter space, achieving a purity-limited average two-qubit Pauli error of 3.8×10^{-3} per fSim gate.

Observation of topological transitions in interacting quantum circuits.

Topology, with its abstract mathematical constructs, often manifests itself in physics and has a pivotal role in our understanding of natural phenomena. Notably, the discovery of topological phases in condensed-matter systems has changed the modern conception of phases of matter. The global nature of topological ordering, however, makes direct experimental probing an outstanding challenge. Present experimental tools are mainly indirect and, as a result, are inadequate for studying the topology of physical systems at a fundamental level. Here we employ the exquisite control afforded by state-of-the-art superconducting quantum circuits to investigate topological properties of various quantum systems. The essence of our approach is to infer geometric curvature by measuring the deflection of quantum trajectories in the curved space of the Hamiltonian. Topological properties are then revealed by integrating the curvature over closed surfaces, a quantum analogue of the Gauss-Bonnet theorem. We benchmark our technique by investigating basic topological concepts of the historically important Haldane model after mapping the momentum space of this condensed-matter model to the parameter space of a single-qubit Hamiltonian. In addition to constructing the topological phase diagram, we are able to visualize the microscopic spin texture of the associated states and their evolution across a topological phase transition. Going beyond non-interacting systems, we demonstrate the power of our method by studying topology in an interacting quantum system. This required a new qubit architecture that allows for simultaneous control over every term in a two-qubit Hamiltonian. By exploring the parameter space of this Hamiltonian, we discover the emergence of an interaction-induced topological phase. Our work establishes a powerful, generalizable experimental platform to study topological phenomena in quantum systems.

Obstacles to compassion-giving among nursing and midwifery managers: an international study.

AIM: To explore nursing and midwifery managers' views regarding obstacles to compassion-giving across country cultures. BACKGROUND: The benefit of compassionate leadership is being advocated, but despite the fact that health care is invariably conducted within culturally diverse workplaces, the interconnection of culture, compassion and leadership is rarely addressed. Furthermore, evidence on how cultural factors hinder the expression of compassion among nursing and midwifery managers is lacking. METHODS: Cross-sectional, exploratory, international online survey involving 1 217 participants from 17 countries. Managers' responses on open-ended questions related to barriers for providing compassion were entered and thematically analysed through NVivo. RESULTS: Three key themes related to compassion-giving obstacles emerged across countries: 1. related to the managers' personal characteristics and experiences; 2. system-related; and 3. staff-related. CONCLUSIONS: Obstacles to compassion-giving among managers vary across countries. An understanding of the variations across countries and cultures of what impedes compassion to flourish in health care is important. IMPLICATIONS FOR NURSING PRACTICE AND POLICY: Nursing mangers should wisely use their power by adopting leadership styles that promote culturally competent and compassionate workplaces with respect for human rights. Policymakers should identify training and mentoring needs to enable the development of managers' practical wisdom. Appropriate national and international policies should facilitate the establishment of standards and guidelines for compassionate leadership, in the face of distorted organizational cultures and system-related obstacles to compassion-giving.

Diabatic Gates for Frequency-Tunable Superconducting Qubits.

We demonstrate diabatic two-qubit gates with Pauli error rates down to 4.3(2)×10^{-3} in as fast as 18 ns using frequency-tunable superconducting qubits. This is achieved by synchronizing the entangling parameters with minima in the leakage channel. The synchronization shows a landscape in gate parameter space that agrees with model predictions and facilitates robust tune-up. We test both iswap-like and cphase gates with cross-entropy benchmarking. The presented approach can be extended to multibody operations as well.

Fluctuations of Energy-Relaxation Times in Superconducting Qubits.

Superconducting qubits are an attractive platform for quantum computing since they have demonstrated high-fidelity quantum gates and extensibility to modest system sizes. Nonetheless, an outstanding challenge is stabilizing their energy-relaxation times, which can fluctuate unpredictably in frequency and time. Here, we use qubits as spectral and temporal probes of individual two-level-system defects to provide direct evidence that they are responsible for the largest fluctuations. This research lays the foundation for stabilizing qubit performance through calibration, design, and fabrication.

Nanoparticles confined to a spherical surface in the presence of an external field: Interaction forces and induced microstructure.

The structural response of a set of charged nanoparticles confined to move on a spherical surface under the influence of an external field is studied by Brownian Dynamics (BD) simulations and by an integral equation approach (IEA). Considering an identical nanoparticle as the source of the external field, we analyze the force exerted by the N confined particles on the external one, as well as the corresponding potential energy, focusing on their dependence on the distance of the external particle to the center of the sphere r0. The connection of the force and potential to the equilibrium local distribution of the adsorbed particles, that is, the microstructure within the spherical monolayer induced by the external nanoparticle, which is also dependent on r0, is elucidated by this analysis. It is found that the external particle needs to surmount a considerable potential barrier when moving toward the spherical surface, although much smaller than the one generated by a uniform surface distribution with an equivalent amount of charge. This is understood in terms of the correlation hole within the confined monolayer induced by the external particle. Another interesting conclusion is that the IEA provides an accurate, almost quantitative, description of the main features observed in the BD results, yet it is much less computationally demanding. The connection of these results with the overall chemical equilibrium of charged surfactant nanoparticles in the context of Pickering emulsions is also briefly discussed.

Observation of Classical-Quantum Crossover of 1/f Flux Noise and Its Paramagnetic Temperature Dependence.

By analyzing the dissipative dynamics of a tunable gap flux qubit, we extract both sides of its two-sided environmental flux noise spectral density over a range of frequencies around 2k_{B}T/h≈1 GHz, allowing for the observation of a classical-quantum crossover. Below the crossover point, the symmetric noise component follows a 1/f power law that matches the magnitude of the 1/f noise near 1 Hz. The antisymmetric component displays a 1/T dependence below 100 mK, providing dynamical evidence for a paramagnetic environment. Extrapolating the two-sided spectrum predicts the linewidth and reorganization energy of incoherent resonant tunneling between flux qubit wells.

The Langmuir-Hinshelwood approach for kinetic evaluation of cucurbit[7]uril-capped gold nanoparticles in the reduction of the antimicrobial nitrofurantoin.

In this work, gold nanoparticles protected by the macrocycle cucurbit[7]uril were used as a catalyst in the reduction of the hazardous antimicrobial nitrofurantoin. 4-Nitrophenol was also employed as the substrate of the reduction for comparative purposes. The kinetic data were modeled to the Langmuir-Hinshelwood equation to know the affinities of the reactants for the surface and the real kinetic constants, a comparison at the molecular level that is made for the first time. From the results, it was observed that the adsorption of nitrofurantoin was stronger than that of 4-nitrophenol whilst the kinetic constant on the surface was higher for 4-nitrophenol than for nitrofurantoin. Additionally, shifts in the nanoparticle surface plasmon band permitted insights to be obtained into the adsorption rate and strength. The reaction induction times were also investigated and were highly dependent on the borohydride concentration and, due to the higher surface affinity of nitrofurantoin compared with 4-nitrophenol, an increase in nitrofurantoin concentration increased the induction time, while a lag phase was not observed for 4-nitrophenol.

Measurement-Induced State Transitions in a Superconducting Qubit: Beyond the Rotating Wave Approximation.

Many superconducting qubit systems use the dispersive interaction between the qubit and a coupled harmonic resonator to perform quantum state measurement. Previous works have found that such measurements can induce state transitions in the qubit if the number of photons in the resonator is too high. We investigate these transitions and find that they can push the qubit out of the two-level subspace, and that they show resonant behavior as a function of photon number. We develop a theory for these observations based on level crossings within the Jaynes-Cummings ladder, with transitions mediated by terms in the Hamiltonian that are typically ignored by the rotating wave approximation. We find that the most important of these terms comes from an unexpected broken symmetry in the qubit potential. We confirm the theory by measuring the photon occupation of the resonator when transitions occur while varying the detuning between the qubit and resonator.

Design of a holographic tracking module for long-range retroreflector free-space systems.

Weight reduction and low power consumption are key requirements in the next generation of unmanned aerial vehicles (UAVs). To communicate with an operator, a secured link between the UAV and a ground-based station is desirable. To realize these links, retroreflecting free-space optics is potentially attractive as it offers light weight and low complexity at the UAV. However, the base station requires a high-performance tracking module to enable a steady illumination of the UAV retroreflector. In this paper, we present the design and implementation of a tracking system, which consists of coarse tracking and holographic fine tracking modules working cooperatively. Using this system, experimental field trials were carried out by mounting a multiple-quantum-well-based modulated retroreflector on a commercial UAV. A 2 Mbps optical link was achieved with a bit error rate of ∼2×10-4 at a link range of 300 m.

Using cornstarch in microparticulate diets for larvicultured tropical gar (Atractosteus tropicus).

Aquaculture in Mexico has been developed by the cultivation of commercial species. In Tabasco, the cultivation of native species is mainly limited by the lack of nutrition studies to support its crop profitability. Among these species is the tropical gar (Atractosteus tropicus), which has great potential for cultivation. However, the nutritional value of carbohydrates in diets for this species which contribute to improved growth and survival, have not been evalulated,. Thus, in the present investigation, isoprotein and isolipid diets have been designed based on the substitution of cellulose by corn starch (D1: 0% starch-15% cellulose, D2: 7.5% starch-7.5% cellulose and D3: 15% starch-0% cellulose) and compared with a commercial trout diet (45% protein and 16% lipids). A total of 1800 larvae (0.008 ± 0.002 g and 10.5 ± LT 0.126 mm) were used, distributed in a recirculation system in order to evaluate growth and survival for 30 days. The results show higher growth and survival of 97% of larvae fed the D3 diet, while cannibalism in the species was mitigated. Major digestive enzyme activities occurred (acid protease, alkaline protease, trypsin, chymotrypsin, leucine aminopeptidase, carboxypeptidase A, lipase, α-glucosidase and amylase) for larvae fed D3. It is concluded that the contribution of corn starch (15%) replacing cellulose in the diet improves growth and survival of this species.

International study on nurses' views and experiences of compassion.

BACKGROUND: Compassion is considered the cornerstone of nursing practice. However, the recent failures in delivering high-quality compassionate nursing care in the UK's National Health Service have brought the topic of compassion to the attention of the public, service providers, policy makers and academics. AIM: The aim of this study was to explore the nurses' views and experiences of a number of compassion-related issues in nursing and describe similarities and differences at an international level as well as from the different nursing roles of the participating nurses. METHODS: An exploratory, cross-sectional descriptive study, using the International Online Compassion Questionnaire. A total of 1323 nurses from 15 countries completed the questionnaire. RESULTS: The majority of participants (59.5%) defined compassion as "Deep awareness of the suffering of others and wish to alleviate it" but definitions of compassion varied by country. Of participants, 69.6% thought compassion was very important in nursing and more than half (59.6%) of them argued that compassion could be taught. However, only 26.8% reported that the correct amount and level of teaching is provided. The majority of the participants (82.6%) stated that their patients prefer knowledgeable nurses with good interpersonal skills. Only 4.3% noted that they are receiving compassion from their managers. A significant relationship was found between nurses' experiences of compassion and their views about teaching of compassion. CONCLUSION: Our study is unique in identifying the views and experiences of nurses from 15 different countries worldwide. The findings reveal that compassion is neither addressed adequately in nursing education nor supported in the practice environment by managers. LIMITATIONS: Self-report bias was inherent to our survey study design. Furthermore, the individual cultural differences and similarities in the findings are difficult to extrapolate owing to the fact that our analysis was at country level, as well as at the level of the participating nurses. IMPLICATIONS FOR NURSING POLICY: Understanding the influence of culture on nurses' views about compassion is critical in the current multicultural healthcare environment and merits further research. This will potentially drive changes in nursing education (ensuring that compassion is taught to nurses) and in the way healthcare leaders and managers foster a compassionate culture within their organizations (e.g. by leading by example and compassionate to their staff).

Development of digestive tract and enzyme activities during the early ontogeny of the tropical gar Atractosteus tropicus.

Changes in digestive enzyme activity and histology were studied in Atractosteus tropicus embryos, larvae and juvenile periods. Alkaline protease, chymotrypsin, carboxypeptidase A, lipase and α-amylase were detected in all periods and gradually increased until reaching the maximum peak in juveniles; meanwhile, acid protease was first detected at 5 days after hatching (dah) when first feeding started and trypsin and leucine aminopeptidase activities were detected from 19 dah, their values being increased gradually until reaching a maximum value at 31 dah. Acid and alkaline phosphatase activities increased from yolk-sac absorption (3 dah) until day 31 after hatching. Zymogram for acid protease showed two bands in active forms (0.4 and 0.5 Rfs) from day 5 after hatching and a third protease form (0.3 Rf) that appears at 31 dah. Two active forms (26.3 and 24.9 kDa) were detected using SDS-PAGE alkaline proteases zymogram at 5 dah, and an additional active form (44.1 kDa) was detected at 7 dah. Regarding the histological development of the digestive system, the exocrine pancreas containing zymogen granules was already visible at 3 dah, whereas at 5 dah first gastric glands were already detected in the stomach. Between 7 and 9 dah, the digestive tract of A. tropicus resembled that of a juvenile specimen with a well-developed and short oesophagus, stomach divided into a glandular and non-glandular (pyloric) stomach, folded intestine with pyloric caeca and a well-developed spiral valve (posterior intestine). Considering this, larvae of A. tropicus are capable of digesting several foods from yolk absorption (3 dah), maximizing its activities at 15 dah, age at which the organisms maximize its capability to absorb nutrients from diets provided.

Optimal quantum control using randomized benchmarking.

We present a method for optimizing quantum control in experimental systems, using a subset of randomized benchmarking measurements to rapidly infer error. This is demonstrated to improve single- and two-qubit gates, minimize gate bleedthrough, where a gate mechanism can cause errors on subsequent gates, and identify control crosstalk in superconducting qubits. This method is able to correct parameters so that control errors no longer dominate and is suitable for automated and closed-loop optimization of experimental systems.

Qubit Architecture with High Coherence and Fast Tunable Coupling.

We introduce a superconducting qubit architecture that combines high-coherence qubits and tunable qubit-qubit coupling. With the ability to set the coupling to zero, we demonstrate that this architecture is protected from the frequency crowding problems that arise from fixed coupling. More importantly, the coupling can be tuned dynamically with nanosecond resolution, making this architecture a versatile platform with applications ranging from quantum logic gates to quantum simulation. We illustrate the advantages of dynamical coupling by implementing a novel adiabatic controlled-z gate, with a speed approaching that of single-qubit gates. Integrating coherence and scalable control, the introduced qubit architecture provides a promising path towards large-scale quantum computation and simulation.

Partial characterization of digestive proteases in tropical gar Atractosteus tropicus juveniles.

Tropical gar (Atractosteus tropicus) is an economically and socially important freshwater species from Southeastern Mexico, with a high aquaculture potential. With this in mind, the purpose of this study was to characterize the digestive proteases of tropical gar juveniles through biochemical and electrophoretic analyses. Twenty specimens with an average weight of 73.6 ± 12.7 g were used to obtain stomach and intestinal tissue from which multienzymatic extracts were prepared. The general activities of the acid and alkaline proteases were evaluated, as well as the specific activities of trypsin, chymotrypsin, leucine aminopeptidase and carboxypeptidase A. The effect of the pH and temperature on the proteases was also analyzed, together with the composition of the multienzymatic extracts using protease inhibitors and electrophoretic tests. Results showed that A. tropicus have a functional stomach in which protein hydrolysis starts with pepsin and which contains endo- and exopeptidases (trypsin, chymotrypsin, leucine aminopeptidase and carboxypeptidase A) and proteases that are resistant to high temperatures (45 and 55 °C for alkaline and acid proteases, respectively) and pH values. Using zymogram technique, we found two acid protease isoforms (0.35 and 0.71 rf) and five alkaline protease isoforms (83.7, 43.7, 27.5, 24.0 and 19.4 kDa), which decrease or disappear with the different inhibitors. Thus, this species is considered to be a carnivore capable of adapting to its environment by consuming different types of proteins from preys and also could adapt rapidly to consume a compound diet with different animal protein sources.