An addressable quantum dot qubit with fault-tolerant control fidelity

Exciting progress towards spin-based quantum computing has recently been made with qubits realized using nitrogen-vacancy (N-V) centers in diamond and phosphorus atoms in silicon, including the demonstration of long coherence times made possible by the presence of spin-free isotopes of carbon and silicon. However, despite promising single-atom nanotechnologies, there remain substantial challenges in coupling such qubits and addressing them individually. Conversely, lithographically defined quantum dots have an exchange coupling that can be precisely engineered, but strong coupling to noise has severely limited their dephasing times and control fidelities. Here we combine the best aspects of both spin qubit schemes and demonstrate a gate-addressable quantum dot qubit in isotopically engineered silicon with a control fidelity of 99.6%, obtained via Clifford based randomized benchmarking and consistent with that required for fault-tolerant quantum computing. This qubit has orders of magnitude improved coherence times compared with other quantum dot qubits, with T_2* = 120 mus and T_2 = 28 ms. By gate-voltage tuning of the electron g*-factor, we can Stark shift the electron spin resonance (ESR) frequency by more than 3000 times the 2.4 kHz ESR linewidth, providing a direct path to large-scale arrays of addressable high-fidelity qubits that are compatible with existing manufacturing technologies

Increased circulating ANG II and TNF-α represents important risk factors in obese Saudi adults with hypertension irrespective of diabetic status and BMI

Central adiposity is a significant determinant of obesity-related hypertension risk, which may arise due to the pathogenic inflammatory nature of the abdominal fat depot. However, the influence of pro-inflammatory adipokines on blood pressure in the obese hypertensive phenotype has not been well established in Saudi subjects. As such, our study investigated whether inflammatory factors may represent useful biomarkers to delineate hypertension risk in a Saudi cohort with and without hypertension and/or diabetes mellitus type 2 (DMT2). Subjects were subdivided into four groups: healthy lean controls (age: 47.9±5.1 yr; BMI: 22.9±2.1 Kg/m2), non-hypertensive obese (age: 46.1±5.0 yr; BMI: 33.7±4.2 Kg/m2), hypertensive obese (age: 48.6±6.1 yr; BMI: 36.5±7.7 Kg/m2) and hypertensive obese with DMT2 (age: 50.8±6.0 yr; BMI: 35.3±6.7 Kg/m2). Anthropometric data were collected from all subjects and fasting blood samples were utilized for biochemical analysis. Serum angiotensin II (ANG II) levels were elevated in hypertensive obese (p<0.05) and hypertensive obese with DMT2 (p<0.001) compared with normotensive controls. Systolic blood pressure was positively associated with BMI (p<0.001), glucose (p<0.001), insulin (p<0.05), HOMA-IR (p<0.001), leptin (p<0.01), TNF-α (p<0.001) and ANG II (p<0.05). Associations between ANG II and TNF-α with systolic blood pressure remained significant after controlling for BMI. Additionally CRP (p<0.05), leptin (p<0.001) and leptin/adiponectin ratio (p<0.001) were also significantly associated with the hypertension phenotype. In conclusion our data suggests that circulating pro-inflammatory adipokines, particularly ANG II and, TNF-α, represent important factors associated with a hypertension phenotype and may directly contribute to predicting and exacerbating hypertension risk

OrgML - a domain specific language for organisational decision-making

Effective decision-making based on precise understanding of an organisation is critical for modern organisations to stay competitive in a dynamic and uncertain business environment. However, the state-of-the-art technologies that are relevant in this context are not adequate to capture and quantitatively analyse complex organisations. This paper discerns the necessary information for an organisational decision-making from management viewpoint, discusses inadequacy of the existing enterprise modelling and specification techniques, proposes a domain specific language to capture the necessary information in machine processable form, and demonstrates how the collected information can be used for a simulation-based evidence-driven organisational decision-making

Fabrication of super-hydrophobic nickel film on copper substrate with improved corrosion inhibition by electrodeposition process

Inspired by the famous “lotus effect”, we have fabricated the super-hydrophobic surfaces with nickel film on copper substrates using a one-step electrodeposition method. By adjusting processing time, water contact angle of as-prepared surfaces can reach as high as 160.3 ± 1.5° with small rolling angle of 3.0 ± 0.5°, showing excellent super-hydrophobicity. After the deposition of nickel coating, the pristine copper surfaces became much rough with packed cauliflower-/thorn-like clusters. This unique surface texture contributed to trapping large amount of air and forming the air cushion underneath the water droplet, which can prevent the liquids contacting the copper substrate. The examination of surface chemical compositions implied that the deposited super-hydrophobic coating consisted of nickel crystals and nickel myristate. In this research, the formation mechanism of the electrodeposited super-hydrophobicity was extensively explained based on the analyses of surface texture and surface chemistry. Moreover, the corrosion resistance of the as-fabricated super-hydrophobic surface was estimated by the potentiodynamic polarization tests as well as the electrochemical impedance spectroscopy (EIS) measurements. The results demonstrate that the super-hydrophobic nickel coating showed excellent corrosion inhibition in simulated seawater solution. The existence of the super-hydrophobic coating could be regarded as a barrier and thus provide a perfect air-liquid interface that inhibits the penetration of the corrosive ions. This facile and effective method of electrodeposition process offers a promising approach for mass production of super-hydrophobic surfaces on various metals

The bashful and the boastful : prestigious leaders and social change in Mesolithic Societies

The creation and maintenance of influential leaders and authorities is one of the key themes of archaeological and historical enquiry. However the social dynamics of authorities and leaders in the Mesolithic remains a largely unexplored area of study. The role and influence of authorities can be remarkably different in different situations yet they exist in all societies and in almost all social contexts from playgrounds to parliaments. Here we explore the literature on the dynamics of authority creation, maintenance and contestation in egalitarian societies, and discuss the implications for our interpretation and understanding of the formation of authorities and leaders and changing social relationships within the Mesolithic

Single electron emission in two-phase xenon with application to the detection of coherent neutrino-nucleus scattering

We present an experimental study of single electron emission in ZEPLIN-III, a two-phase xenon experiment built to search for dark matter WIMPs, and discuss applications enabled by the excellent signal-to-noise ratio achieved in detecting this signature. Firstly, we demonstrate a practical method for precise measurement of the free electron lifetime in liquid xenon during normal operation of these detectors. Then, using a realistic detector response model and backgrounds, we assess the feasibility of deploying such an instrument for measuring coherent neutrino-nucleus elastic scattering using the ionisation channel in the few-electron regime. We conclude that it should be possible to measure this elusive neutrino signature above an ionisation threshold of $\sim$3 electrons both at a stopped pion source and at a nuclear reactor. Detectable signal rates are larger in the reactor case, but the triggered measurement and harder recoil energy spectrum afforded by the accelerator source enable lower overall background and fiducialisation of the active volume

Host-Based Th2 Cell Therapy for Prolongation of Cardiac Allograft Viability

Donor T cell transfusion, which is a long-standing approach to prevent allograft rejection, operates indirectly by alteration of host T cell immunity. We therefore hypothesized that adoptive transfer of immune regulatory host Th2 cells would represent a novel intervention to enhance cardiac allograft survival. Using a well-described rat cardiac transplant model, we first developed a method for ex vivo manufacture of rat host-type Th2 cells in rapamycin, with subsequent injection of such Th2.R cells prior to class I and class II disparate cardiac allografting. Second, we determined whether Th2.R cell transfer polarized host immunity towards a Th2 phenotype. And third, we evaluated whether Th2.R cell therapy prolonged allograft viability when used alone or in combination with a short-course of cyclosporine (CSA) therapy. We found that host-type Th2.R cell therapy prior to cardiac allografting: (1) reduced the frequency of activated T cells in secondary lymphoid organs; (2) shifted post-transplant cytokines towards a Th2 phenotype; and (3) prolonged allograft viability when used in combination with short-course CSA therapy. These results provide further support for the rationale to use “direct” host T cell therapy for prolongation of allograft viability as an alternative to “indirect” therapy mediated by donor T cell infusion

Quantification of atopy, lung function and airway hypersensitivity in adults

<p>Abstract</p> <p>Background</p> <p>Studies in children have shown that concentration of specific serum IgE (sIgE) and size of skin tests to inhalant allergens better predict wheezing and reduced lung function than the information on presence or absence of atopy. However, very few studies in adults have investigated the relationship of quantitative atopy with lung function and airway hyperresponsiveness (AHR).</p> <p>Objective</p> <p>To determine the association between lung function and AHR and quantitative atopy in a large sample of adults from the UK.</p> <p>Methods</p> <p>FEV₁ and FVC (% predicted) were measured using spirometry and airway responsiveness by methacholine challenge (5-breath dosimeter protocol) in 983 subjects (random sample of 800 parents of children enrolled in a population-based birth cohort enriched with 183 patients with physician-diagnosed asthma). Atopic status was assessed by skin prick tests (SPT) and measurement of sIgE (common inhalant allergens). We also measured indoor allergen exposure in subjects' homes.</p> <p>Results</p> <p>Spirometry was completed by 792 subjects and 626 underwent methacholine challenge, with 100 (16.0%) having AHR (dose-response slope>25). Using sIgE as a continuous variable in a multiple linear regression analysis, we found that increasing levels of sIgE to mite, cat and dog were significantly associated with lower FEV₁ (mite p = 0.001, cat p = 0.0001, dog p = 2.95 × 10^-8). Similar findings were observed when using the size of wheal on skin testing as a continuous variable, with significantly poorer lung function with increasing skin test size (mite p = 8.23 × 10^-8, cat p = 3.93 × 10^-10, dog p = 3.03 × 10^-15, grass p = 2.95 × 10^-9). The association between quantitative atopy with lung function and AHR remained unchanged when we repeated the analyses amongst subjects defined as sensitised using standard definitions (sIgE>0.35 kUa/l, SPT-3 mm>negative control).</p> <p>Conclusions</p> <p>In the studied population, lung function decreased and AHR increased with increasing sIgE levels or SPT wheal diameter to inhalant allergens, suggesting that atopy may not be a dichotomous outcome influencing lung function and AHR.</p