Probing Decoherence with Electromagnetically Induced Transparency in Superconductive Quantum Circuits

Superconductive quantum circuits (SQCs) comprise quantized energy levels that may be coupled via microwave electromagnetic fields. Described in this way, one may draw a close analogy to atoms with internal (electronic) levels coupled by laser light fields. In this Letter, we present a superconductive analog to electromagnetically induced transparency (S-EIT) that utilizes SQC designs of present day experimental consideration. We discuss how S-EIT can be used to establish macroscopic coherence in such systems and, thereby, utilized as a sensitive probe of decoherence.Comment: 5 pages, 3 figure

Impact of time-ordered measurements of the two states in a niobium superconducting qubit structure

Measurements of thermal activation are made in a superconducting, niobium Persistent-Current (PC) qubit structure, which has two stable classical states of equal and opposite circulating current. The magnetization signal is read out by ramping the bias current of a DC SQUID. This ramping causes time-ordered measurements of the two states, where measurement of one state occurs before the other. This time-ordering results in an effective measurement time, which can be used to probe the thermal activation rate between the two states. Fitting the magnetization signal as a function of temperature and ramp time allows one to estimate a quality factor of 10^6 for our devices, a value favorable for the observation of long quantum coherence times at lower temperatures.Comment: 14 pages, 4 figure

DC measurements of macroscopic quantum levels in a superconducting qubit structure with a time-ordered meter

DC measurements are made in a superconducting, persistent current qubit structure with a time-ordered meter. The persistent-current qubit has a double-well potential, with the two minima corresponding to magnetization states of opposite sign. Macroscopic resonant tunneling between the two wells is observed at values of energy bias that correspond to the positions of the calculated quantum levels. The magnetometer, a Superconducting Quantum Interference Device (SQUID), detects the state of the qubit in a time-ordered fashion, measuring one state before the other. This results in a different meter output depending on the initial state, providing different signatures of the energy levels for each tunneling direction. From these measurements, the intrawell relaxation time is found to be about 50 microseconds.Comment: 17 pages, 7 figure

Novel gallium(III) complexes transported by MDR1 P-glycoprotein: potential PET imaging agents for probing P-glycoprotein-mediated transport activity in vivo

AbstractBackground: Multidrug resistance (MDR) mediated by expression of MDR1 P-glycoprotein (Pgp) represents one of the best characterized barriers to chemotherapy in cancer patients. Positron emission tomography (PET) agents for analysis of Pgp-mediated drug transport activity in vivo would enable noninvasive assessment of chemotherapeutic regimens and MDR gene therapy.Results: Candidate Schiff-base phenolic gallium(III) complexes were synthesized from their heptadentate precursors and gallium(III)acetylacetonate. Crystal structures demonstrated a hexacoordinated central gallium with overall trans-pseudo-octahedral geometry. Radiolabeled 67Ga-complexes were obtained in high purity and screened in drug-sensitive (Pgp−) and MDR (Pgp+) tumor cells. Compared with control, lead compound 6 demonstrated antagonist-reversible 55-fold lower accumulation in Pgp-expressing MDR cells. Furthermore, compared with wild-type control, quantitative pharmacokinetic analysis showed markedly increased penetration and retention of 6 in brain and liver tissues of mdr1a/b(−/−) gene disrupted mice, correctly mapping Pgp-mediated transport activity at the capillary blood–brain barrier and hepatocellular biliary cannalicular surface in vivo.Conclusions: These results indicate that gallium(III) complex 6 is recognized by MDR1 Pgp as an avid transport substrate, thereby providing a useful scaffold to generate 68Ga radiopharmaceuticals for molecular imaging of Pgp transport activity in tumors and tissues in vivo using PET

BlinkML: Efficient Maximum Likelihood Estimation with Probabilistic Guarantees

The rising volume of datasets has made training machine learning (ML) models a major computational cost in the enterprise. Given the iterative nature of model and parameter tuning, many analysts use a small sample of their entire data during their initial stage of analysis to make quick decisions (e.g., what features or hyperparameters to use) and use the entire dataset only in later stages (i.e., when they have converged to a specific model). This sampling, however, is performed in an ad-hoc fashion. Most practitioners cannot precisely capture the effect of sampling on the quality of their model, and eventually on their decision-making process during the tuning phase. Moreover, without systematic support for sampling operators, many optimizations and reuse opportunities are lost. In this paper, we introduce BlinkML, a system for fast, quality-guaranteed ML training. BlinkML allows users to make error-computation tradeoffs: instead of training a model on their full data (i.e., full model), BlinkML can quickly train an approximate model with quality guarantees using a sample. The quality guarantees ensure that, with high probability, the approximate model makes the same predictions as the full model. BlinkML currently supports any ML model that relies on maximum likelihood estimation (MLE), which includes Generalized Linear Models (e.g., linear regression, logistic regression, max entropy classifier, Poisson regression) as well as PPCA (Probabilistic Principal Component Analysis). Our experiments show that BlinkML can speed up the training of large-scale ML tasks by 6.26x-629x while guaranteeing the same predictions, with 95% probability, as the full model.Comment: 22 pages, SIGMOD 201

Multicentre, randomised controlled trial to investigate the effects of parental touch on relieving acute procedural pain in neonates (Petal)

This is the final version. Available on open access from BMJ Publishing via the DOI in this record. Data availability statement: Data sharing not applicable as no data sets generated and/or analysed for this study. Not applicable.INTRODUCTION: Newborn infants routinely undergo minor painful procedures as part of postnatal care, with infants born sick or premature requiring a greater number of procedures. As pain in early life can have long-term neurodevelopmental consequences and lead to parental anxiety and future avoidance of interventions, effective pain management is essential. Non-pharmacological comfort measures such as breastfeeding, swaddling and sweet solutions are inconsistently implemented and are not always practical or effective in reducing the transmission of noxious input to the brain. Stroking of the skin can activate C-tactile fibres and reduce pain, and therefore could provide a simple and safe parent-led intervention for the management of pain. The trial aim is to determine whether parental touch prior to a painful clinical procedure provides effective pain relief in neonates. METHODS AND ANALYSIS: This is a multicentre randomised controlled trial. A total of 112 neonates born at 35 weeks' gestation or more requiring a blood test in the first week of life will be recruited and randomised to receive parental stroking either preprocedure or postprocedure. We will record brain activity (EEG), cardiac and respiratory dynamics, oxygen saturation and facial expression to provide proxy pain outcome measures. The primary outcome will be the reduction of noxious-evoked brain activity in response to a heel lance. Secondary outcomes will be a reduction in clinical pain scores (Premature Infant Pain Profile-Revised), postprocedural tachycardia and parental anxiety. ETHICS AND DISSEMINATION: The study has been approved by the London-South East Research Ethics Committee (ref: 21/LO/0523). The results will be widely disseminated through peer-reviewed publications, international conferences and via our partner neonatal charities Bliss and Supporting the Sick Newborn And their Parents (SSNAP). If the parental tactile intervention is effective, recommendations will be submitted via the National Health Service clinical guideline adoption process. STUDY STATUS: Commenced September 2021. TRIAL REGISTRATION NUMBER: NCT04901611; 14 135 962.Wellcome TrustBlis

Writing Russia's future: paradigms, drivers, and scenarios

The development of prediction and forecasting in the social sciences over the past century and more is closely linked with developments in Russia. The Soviet collapse undermined confidence in predictive capabilities, and scenario planning emerged as the dominant future-oriented methodology in area studies, including the study of Russia. Scenarists anticipate multiple futures rather than predicting one. The approach is too rarely critiqued. Building on an account of Russia-related forecasting in the twentieth century, analysis of two decades of scenarios reveals uniform accounts which downplay the insights of experts and of social science theory alike