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Superconducting traveling wave parametric amplifiers (TWPAs) are broadband near-quantum limited microwave amplifiers commonly used for qubit readout and a wide range of other applications in quantum technologies. The performance of these amplifiers depends on achieving impedance matching to minimize reflected signals. Here, we apply a microwave calibration technique to extract the S-parameters of a Josephson junction based TWPA in-operando. This enables reflections occurring at the TWPA and its extended network of components to be quantified, and we find that the in-operation performance can be well described by the off-state measured S-parameters. [ABSTRACT FROM AUTHOR]

Parents of children with neurodevelopmental conditions (NDC) are at risk of experiencing elevated levels of parental stress. Access to robust instruments to assess parental stress is important in both clinical and research contexts. Objective: We aimed to evaluate the psychometric properties of a Swedish version of the Parental Stress Scale (PSS), completed by parents of 3- to 17-year-old children, with and without NDCs.

MgB2 nanobridges were fabricated by e-beam lithography and Ar-ion beam milling. Nanobridges of widths ranging from 60 nm to 1 μm and 3 μm in length were realized by Ar-ion beam milling using amorphous carbon as etching mask. The processing did not harm the superconducting properties appreciably. High values of the critical current density, more than 10 MA/cm2, were measured for bridges with widths down to 60 nm. Current-voltage (I-V) characteristics showed a behavior typical of a bridge going normal, after the critical current is exceeded, and remaining normal as the current is decreased to a lower switch back value due to Joule heating. We could also observe switching behavior in some bridges indicating formation of normal hotspots in the bridges before they returned to their superconducting state. Alternative explanations may include natural grain boundaries in the film or the movement of Abrikosov vortices. The current-voltage (I-V) characteristics showing critical current densities up to 5×107A/cm2 indicates excellent film properties in the nanobridges. [ABSTRACT FROM AUTHOR]

Recent experiments have indicated surface spins in superconducting devices to be associated with both flux- and charge noise. In particular, for superconducting resonators, where the frequency noise is dominated by the electric field from the resonator coupling to spurious two-level material defects, information on noise in applied magnetic fields is lacking. Here, we present measurements of frequency noise in a superconducting resonator with a centre frequency f 0 = 6.1 GHz in fields exceeding the Zeeman splitting of surface spins (up to 310 mT), showing that the charge-induced noise is unaffected by the applied magnetic field. [ABSTRACT FROM AUTHOR]

Noise and decoherence due to spurious two-level systems located at material interfaces are long-standing issues for solid-state quantum devices. Efforts to mitigate the effects of twolevel systems have been hampered by a lack of knowledge about their chemical and physical nature. Here, by combining dielectric loss, frequency noise and on-chip electron spin resonance measurements in superconducting resonators, we demonstrate that desorption of surface spins is accompanied by an almost tenfold reduction in the charge-induced frequency noise in the resonators. These measurements provide experimental evidence that simultaneously reveals the chemical signatures of adsorbed magnetic moments and highlights their role in generating charge noise in solid-state quantum devices. [ABSTRACT FROM AUTHOR]

Objectives: To evaluate how a snack influences the blood glucose profile during treatment with preprandial regular human insulin.Design: In a randomized study a mid-morning snack either was or was not served. Insulin was given 30 min before the usual breakfast of the patients. Plasma free insulin and blood glucose were repeatedly determined for 5 h.Setting: Outpatient clinic at a university hospital.Subjects: Twenty patients with type 1 diabetes treated with multiple injections of regular insulin (Actrapid) and eight non-diabetic subjects.Interventions: A mid-morning snack either was or was not served 2 h after the usual morning insulin injection.Main Outcome Measures: A difference in the blood glucose profile after a mid-morning snack.Results: With a snack there was no difference in blood glucose fasting and at 12.30 h, whilst without a snack there was a decrease of almost 4 mmol L-1, several patients experienced low blood glucose and three had hypoglycaemia. An extended peak of free insulin was reached 30 min after the insulin injection with a slow decrease to the fasting level after 5 h. After the insulin injection a significant decrease in blood glucose occurred within 30-45 min.Conclusions: A snack 2 h after the insulin injection results in a smoother blood glucose profile and reduces the risk of hypoglycaemia in patients with type 1 diabetes treated with preprandial regular human insulin. Furthermore, the recommended interval of 30 min between insulin injection and a meal may be too long. [ABSTRACT FROM AUTHOR]

We demonstrate the coupling of rare-earth ions locally implanted in a substrate (Gd3+ in Al2O3) to a superconducting NbN lumped-element micro-resonator. The hybrid device is fabricated by a con-trolled ion implantation of rare-earth ions in well-defined micron-sized areas, aligned to lithograph-ically defined micro-resonators. The technique does not degrade the internal quality factor of the resonators which remain above 105. Using microwave absorption spectroscopy, we observe electron-spin resonances in good agreement with numerical modelling and extract corresponding coupling rates of the order of 1 MHz and spin linewidths of 50-65 MHz [ABSTRACT FROM AUTHOR]

We experimentally and theoretically study the frequency shift of a driven cavity coupled to a superconducting charge qubit. In addition to previous studies, here we also consider drive strengths large enough to energetically allow for quasiparticle creation. Quasiparticle tunnelling leads to the inclusion of more than two charge states in the dynamics. To explain the observed effects, we develop a master equation for the microwave dressed charge states, including quasiparticle tunnelling. A bimodal behaviour of the frequency shift as a function of gate voltage can be used for sensitive charge detection. However, at weak drives, the charge sensitivity is significantly reduced by nonequilibrium quasiparticles, which induce transitions to a non-sensitive state. Unexpectedly, at high-enough drives, the quasiparticle tunnelling enables a very fast relaxation channel to the sensitive state. In this regime, the charge sensitivity is thus robust against externally injected quasiparticles and the desired dynamics prevail over a broad range of temperatures. We find very good agreement between the theory and experiment over a wide range of drive strengths and temperatures. [ABSTRACT FROM AUTHOR]

Slow noise processes, with characteristic timescales ~1 s, have been studied in planar superconducting resonators. A frequency-locked loop is employed to track deviations of the resonator center frequency with high precision and bandwidth. Comparative measurements are made in varying microwave drive and temperature, and between bare resonators and those with an additional dielectric layer. All resonators are found to exhibit flicker frequency noise which increases with decreasing microwave drive. We also show that an increase in temperature results in a saturation of flicker noise in resonators with an additional dielectric layer, while bare resonators stop exhibiting flicker noise, instead showing a random frequency walk process. [ABSTRACT FROM AUTHOR]

We present a new application and implementation of the Pound-locking technique for the interrogation of superconducting microresonators. We discuss how by comparing against stable frequency sources this technique can be used to characterize properties of resonators that cannot be accessed using traditional methods. Specifically, by analyzing the noise spectra and the Allan deviation, we obtain valuable information about the nature of the noise in superconducting planar resonators. This technique also greatly improves the read-out accuracy and measurement throughput compared to conventional methods [ABSTRACT FROM AUTHOR]

Theoretical exploration of network structure significance requires a range of different networks for comparison. Here, we present a new method to construct networks in a spatial setting that uses spectral methods in combination with a probability distribution function. Nearly all previous algorithms for network construction have assumed randomized distribution of links or a distribution dependent on the degree of the nodes. We relax those assumptions. Our algorithm is capable of creating spectral networks along a gradient from random to highly clustered or diverse networks. Number of nodes and link density are specified from start and the structure is tuned by three parameters (γ, σ, κ). The structure is measured by fragmentation, degree assortativity, clustering and group betweenness of the networks. The parameter γ regulates the aggregation in the spatial node pattern and σ and κ regulates the probability of link forming. [ABSTRACT FROM AUTHOR]

Objective: To study whether administration of 1.25 and 5.0 mg ramipril daily, compared with placebo treatment, reduces the urinary albumin excretion rate (UAER) in normotensive patients with type 1 diabetes.Research Design and Methods: Ramipril was administered double blind at two different doses (1.25 [n = 19] and 5.0 mg [n = 18]), and compared with placebo (n = 18) after a single-blind placebo period of 1-4 weeks. The patients (total, n = 55; women, n = 14) were followed for 2 years. To document an effect on the renin-angiotensin system, ACE activity and plasma-renin activity (PRA) were measured. In addition, 24-h ambulatory blood pressure (BP) was recorded at baseline and repeated after 1 and 2 years using a Spacelab 90207 ambulatory BP recording device (Spacelab, Redmont, CA).Results: Both doses of ramipril were sufficient to reduce ACE activity and to increase PRA significantly as compared with placebo (P < 0.05 for both). On the other hand, neither ambulatory nor clinic BP was affected by either dose of ramipril compared with the placebo group. There was no progression of UAER in the placebo group during the 2 years of the study. Analysis of covariance showed no differences in UAER between the three treatment groups at year 1 (P = 0.94) or year 2 (P = 0.97), after adjusting for baseline. Furthermore, there were no statistically significant changes from baseline UAER within any of the three treatment groups.Conclusions: Treatment with ramipril did not affect microalbuminuria or clinic or ambulatory BP in this study. On the basis of the present study, we question the clinical use of ACE inhibitors in stably normotensive patients with type 1 diabetes and microalbuminuria in whom a concomitant reduction in BP is not demonstrated. [ABSTRACT FROM AUTHOR]

SummaryAims To study whether changes in endogenous insulin secretion at the same glycaemic control affect the plasma concentrations of lipoproteins in patients with Type 2 diabetes mellitus. Methods Fifteen patients, age 59 ± 2 years (mean ± sem), body weight 86.3 ± 3.0 kg, body mass index 29.6 ± 0.9 kg/m2 were treated with sulphonylurea and insulin in combination or with insulin alone in a randomized, double-blind, crossover study. All patients were treated with a multiple daily injection regimen with the addition of glibenclamide 10.5 mg daily or placebo tablets. Results During combination therapy, the dose of insulin was 25% less (P < 0.002) and there was a 29% increase in plasma C-peptide concentration (P = 0.01). Plasma levels of free insulin were not changed. Plasma levels of sex hormone-binding globulin (SHBG) and insulin-like growth factor-binding protein (IGFBP)-1 were lowered. There were no differences in the 24-h blood glucose profiles or HbA1c (6.0 ± 0.2 vs. 6.3 ± 0.2%; P = 0.16). Body weight was similar. There was a significant decrease in plasma LDL cholesterol (3.04 ± 0.24 vs. 3.41 ± 0.21 mmol/l; P = 0.04), apolipoprotein A1 and of lipoprotein(a) but an increase in VLDL-triglycerides (1.36 ± 0.31 vs. 0.96 ± 0.16 mmol/l; P = 0.02) during combination therapy. The ratio between LDL cholesterol and apolipoprotein B concentrations was significantly lower during combination therapy (P < 0.01). Conclusions Combination therapy with insulin and sulphonylureas increases portal insulin supply and thereby alters liver lipoprotein metabolism when compared with insulin therapy alone. [ABSTRACT FROM AUTHOR]

We describe measurements on microwave coplanar resonators designed for quantum bit experiments. Resonators have been patterned onto sapphire and silicon substrates, and quality factors in excess of a million have been observed. The resonant frequency shows a high sensitivity to magnetic field applied perpendicular to the plane of the film, with a quadratic dependence for the fundamental, second, and third harmonics. Frequency shift of hundreds of linewidths can be obtained with no change in the quality factor. [ABSTRACT FROM AUTHOR]