Fast Gate-Based Readout of Silicon Quantum Dots Using Josephson Parametric Amplification.

Spins in silicon quantum devices are promising candidates for large-scale quantum computing. Gate-based sensing of spin qubits offers a compact and scalable readout with high fidelity, however, further improvements in sensitivity are required to meet the fidelity thresholds and measurement timescales needed for the implementation of fast feedback in error correction protocols. Here, we combine radio-frequency gate-based sensing at 622 MHz with a Josephson parametric amplifier, that operates in the 500-800 MHz band, to reduce the integration time required to read the state of a silicon double quantum dot formed in a nanowire transistor. Based on our achieved signal-to-noise ratio, we estimate that singlet-triplet single-shot readout with an average fidelity of 99.7% could be performed in 1 µs, well below the requirements for fault-tolerant readout and 30 times faster than without the Josephson parametric amplifier. Additionally, the Josephson parametric amplifier allows operation at a lower radio-frequency power while maintaining identical signal-to-noise ratio. We determine a noise temperature of 200 mK with a contribution from the Josephson parametric amplifier (25%), cryogenic amplifier (25%) and the resonator (50%), showing routes to further increase the readout speed.

Strongly Correlated Charge Transport in Silicon Metal-Oxide-Semiconductor Field-Effect Transistor Quantum Dots.

Quantum shot noise probes the dynamics of charge transfers through a quantum conductor, reflecting whether quasiparticles flow across the conductor in a steady stream, or in syncopated bursts. We have performed high-sensitivity shot noise measurements in a quantum dot obtained in a silicon metal-oxide-semiconductor field-effect transistor. The quality of our device allows us to precisely associate the different transport regimes and their statistics with the internal state of the quantum dot. In particular, we report on large current fluctuations in the inelastic cotunneling regime, corresponding to different highly correlated, non-Markovian charge transfer processes. We have also observed unusually large current fluctuations at low energy in the elastic cotunneling regime, the origin of which remains to be fully investigated.

Electrical Control of g-Factor in a Few-Hole Silicon Nanowire MOSFET.

Hole spins in silicon represent a promising yet barely explored direction for solid-state quantum computation, possibly combining long spin coherence, resulting from a reduced hyperfine interaction, and fast electrically driven qubit manipulation. Here we show that a silicon-nanowire field-effect transistor based on state-of-the-art silicon-on-insulator technology can be operated as a few-hole quantum dot. A detailed magnetotransport study of the first accessible hole reveals a g-factor with unexpectedly strong anisotropy and gate dependence. We infer that these two characteristics could enable an electrically driven g-tensor-modulation spin resonance with Rabi frequencies exceeding several hundred mega-Hertz.

A method for evaluating the evolution of clogging: application to the Pampulha Campus infiltration system (Brazil).

In order to evaluate the hydraulic performance of stormwater infiltration trenches, a study was undertaken to assess clogging and its distribution between the bottom and the sides. The method used was based on the calibration of the hydraulic resistance event by event according to Bouwer's model and applied to a demonstration trench in Belo-Horizonte monitored in the framework of the European Project Switch. The calibration was performed by minimizing the distance between measured and modeled infiltration flow rates and by using continuous measurements of rainfall, inflow, water temperature and depth in the trench. The study showed that the methodology and particularly Bouwer's model was able to produce satisfactory results. It revealed a significant clogging evolution within a year, with global resistance increasing by a factor of 9. A significant difference between the bottom and the sides was observed; the bottom being more rapidly prone to clogging. Sudden fluctuations of the hydraulic resistance of the bottom were found that could be explained by very high concentrations of total suspended solids from inflows (about 2,000 mg/L). Clogging of the sides evolves over the time but with a very low rate.

Ecotoxicological characterisation of sediments from stormwater retention basins.

Retention-detention basins are important structures for managing stormwater. However, their long-term operation raises the problem of managing the sediments they accumulate. Potential uses for such sediments have been envisaged, but each sediment must be characterised beforehand to verify its harmlessness. In this paper we address this issue through the development of a battery of bioassays specifically adapted to such sediments. We tested the method on samples taken from four retention basins in the region of Lyon (France). This battery focuses on the toxic effects linked to both the solid phase (ostracod and Microtox(®) solid-phase tests) and the liquid-phase (interstitial water) of sediments (rotifer and Microtox(®) liquid-phase tests). The results obtained permit the sorting of sediments presenting little toxicity, and which could therefore be potentially exploitable, from those from more polluted areas presenting higher toxicity that limits their use.

First case of cyproterone acetate induced multiple meningiomas in identical female twins: A case report.

Meningiomas are the most common tumors of the central nervous system. Most meningiomas are benign and occur mainly in middle-aged women. Only a few cases of meningiomas in identical twins have been reported. Cyproterone acetate (Androcur® Bayer Healthcare SAS) (CPA) is an antiandrogenic progestin used to treat female hirsutism in some countries including France. We report a case of identical twin sisters who developed multiple, atypically located meningiomas in the setting of long-term CPA use. Eighteen-month follow-up showed spontaneous decrease of meningiomas after cessation of CPA. This case illustrates CPA's ability to induce development of atypically located meningiomas that differ even between identical twins, confirms benefit of surgical abstention, and raises questions regarding security of use of CPA.

Unilateral or bilateral adrenalectomy in PPNAD: six cases from a single family followed up over 40 years.

The most frequent endocrine Carney complex manifestation is a bilateral primary pigmented nodular adrenocortical disease and bilateral adrenalectomy (BA) is therefore its main treatment. In this study, a 40 years follow-up of six members of the same family with heterozygous PRKAR1A germline mutation, is reported over two generations. The first cases, two sisters with severe hyperandrogenism and Cushing syndrome (CS) diagnosed in 1972 at age 14 and 25, were successfully treated with unilateral adrenalectomy (UA). Their two brothers were then diagnosed, one with a CS-related severe osteoporosis treated with BA and the other with CS treated with UA. The second generation was diagnosed with CS signs at 7 and 21 years of age and were treated with BA and UA respectively. Out of the four patients treated with UA, the only event possibly related to CS was spontaneous episode of pulmonary embolism, 30 years after surgery. Hormonal evaluation revealed either eucortisolism in one patient or partial adrenal deficiency in two and mild hypercortisolism in one patient. For the two patients with BA, one of them accidentally died. The second one, surprisingly, recovered progressively normal cortisol secretion and circadian variation. Steroid substitution was stopped 6 years after her surgery and we demonstrated by iodocholesterol scintigraphy the presence of bilateral adrenal remnants. In conclusion, our results of long term evolution of PPNAD patients show that UA in this subset of patients could be considered to treat CS.

Multicriteria decision-aid method to evaluate the performance of stormwater infiltration systems over the time.

Nowadays, stormwater infiltration systems are frequently used because of their ability to reduce flows and volumes in downstream sewers, decrease overflows in surface waters and make it possible to recharge groundwater. Moreover, they come in various forms with different uses. Despite these advantages the long term sustainability of these systems is questionable and their real performances have to be assessed taking into account various and sometimes conflicting aspects. To address this problem a decision support system is proposed. It is based on a multicriteria method built to help managers to evaluate the performance of an existing infiltration system at different stages of its lifespan and identify whether it performs correctly or not, according to environmental, socio-economic, technical and sanitary aspects. The paper presents successively: the performance indicators and the way they were built, the multicriteria method to identify if the system works properly and a case study.

Multicriteria procedure for the design and the management of infiltration systems.

Infiltration systems are frequently used as an option to manage urban storm drainage. By reducing flows and volumes in downstream sewers or in surface waters, they decrease the overflows and make it possible to recharge groundwater. They come in various forms with different uses; therefore, their performance is diverse and integrates multiple aspects. Consequently, a multicriteria approach was developed in order to quantify the performance of these systems and to help in decision making problems. For that purpose, a list of performance indicators integrating technical, economical, environmental and social aspects was developed. The performances were defined with the help of a working group composed of engineers from different technical or strategic departments from Greater Lyon and researchers from different fields. The paper presents the last version of the performance indicators tested according to a set of quality requirements: availability of data, relevance, fidelity, precision, sensitivity/robustness. This critical review of the set of indicators has led us to redefine a certain number of indicators, identify numerous biases and allow putting forward general instructions for criterion or indicator construction. The last phase is to propose multicriteria decision aid methods; a procedure using ELECTRE methods should be used.

Long-term hydraulic and pollution retention performance of infiltration systems.

Infiltration techniques are now widely used to manage stormwater in urban areas. These techniques are used and recognized around the world for their many advantages, such as decreasing stormwater flow in sewer systems and recharging groundwater. But numerous cases of infiltration devices that failed after a few years of operation are still being reported. This study, which is based on site-monitoring of operational infiltration systems, is part of the Field Observatory for Urban Water Management (OTHU). The main goals of this study are to improve knowledge of long-term hydraulic behaviour, especially as concerns the clogging speed and the quality of the runoff. This article will present the site, the monitoring process and the model that will be used to assess the hydraulic behaviour. First results of the calibration of the model show that the model is able to assess the hydraulic behaviour of the basin when it is clogged (average value of hydraulic resistance 17.1 h) and when it has been scraped (hydraulic resistance less than 3.8 h). However, further data are needed in order to validate the model. We also show that the experimental setup is well designed to assess the water volume and the sediment brought to the basin with low uncertainties.

Temporal evolution and spatial distribution of heavy metals in a stormwater infiltration basin--estimation of the mass of trapped pollutants.

Infiltration systems are widely used to manage stormwater in urban areas but questions about their long term sustainability need to be addressed. The possible pollution of the groundwater and the concentration of pollutant trapped in the soil are of major interest. This article focuses on the concentration of heavy metals found in the top layer of an infiltration basin. Two sampling campaigns have been undertaken 10 months apart and 200 samples were collected and analysed for lead (Pb), zinc (Zn) and copper (Cu). High concentrations were measured at the surface of the system; pollutant build up over time is clearly evident, especially in the lower lying areas, as well as higher concentrations in the oldest part of the system. Finally, the total mass of heavy metals trapped in the top layer of the systems are evaluated.

Hydraulic performance of biofilters for stormwater management: first lessons from both laboratory and field studies.

In order to improve knowledge on stormwater biofiltration systems, the Facility for Advancing Water Biofiltration (FAWB) was created at Monash University in Melbourne, Australia. One of the aims of FAWB is to improve hydraulic performance of biofilters, given that there are numerous cases of infiltration devices failing after a few years of operation. Experiments were conducted in the field to evaluate the performance of existing systems, and in the lab to understand the factors that influence hydraulic behavior over time. The field experiments show that 43% of tested systems are below nominal Australian guidelines for hydraulic conductivity. The preliminary lab results show a decrease in hydraulic conductivity during the first weeks of operation (mu=66% reduction), although most remain within acceptable limits. Influences of the size of the biofilter relative to its catchment and the importance of the type of media, on the evolution of hydraulic conductivity, are examined.

Comparison between two methodologies for urban drainage decision aid.

The objective of the present work is to compare two methodologies based on multicriteria analysis for the evaluation of stormwater systems. The first methodology was developed in Brazil and is based on performance-cost analysis, the second one is ELECTRE III. Both methodologies were applied to a case study. Sensitivity and robustness analyses were then carried out. These analyses demonstrate that both methodologies have equivalent results, and present low sensitivity and high robustness. These results prove that the Brazilian methodology is consistent and can be used safely in order to select a good solution or a small set of good solutions that could be compared with more detailed methods afterwards.

A CMOS silicon spin qubit.

Silicon, the main constituent of microprocessor chips, is emerging as a promising material for the realization of future quantum processors. Leveraging its well-established complementary metal-oxide-semiconductor (CMOS) technology would be a clear asset to the development of scalable quantum computing architectures and to their co-integration with classical control hardware. Here we report a silicon quantum bit (qubit) device made with an industry-standard fabrication process. The device consists of a two-gate, p-type transistor with an undoped channel. At low temperature, the first gate defines a quantum dot encoding a hole spin qubit, the second one a quantum dot used for the qubit read-out. All electrical, two-axis control of the spin qubit is achieved by applying a phase-tunable microwave modulation to the first gate. The demonstrated qubit functionality in a basic transistor-like device constitutes a promising step towards the elaboration of scalable spin qubit geometries in a readily exploitable CMOS platform.

Statistical analysis of pollution in stormwater infiltration basins.

In order to characterize soil pollution in stormwater infiltration basins, four basins of the Lyon area were selected and sampled. Altogether, 66 soil samples were collected. Each sample was analyzed for pH, cationic exchange capacity, particle size distribution, total organic carbon, total nitrogen, total phosphorus, metals, total hydrocarbons and polycyclic aromatic hydrocarbons (PAHs). Data was explored in a classic way (soil profiles) and using multivariate analysis techniques. Two methods were applied: Principal Component Analysis (PCA) and Cluster Analysis (CA). Main results are presented in this paper. Pollutant concentrations decrease rapidly with depth while pH and grain size increase. Sustainable concentrations are reached at a 50-cm depth, even after 21 years of operation. Multivariate analysis shows how pollution affects each sampling depth.

Performance-costs evaluation for urban storm drainage.

The design process of urban stormwater systems incorporating BMPs involves more complexity unlike the design of classic drainage systems for which just the technique of pipes is likely to be used. This paper presents a simple decision aid methodology and an associated software (AvDren) concerning urban stormwater systems, devoted to the evaluation and the comparison of drainage scenarios using BMPs according to different technical, sanitary, social environmental and economical aspects. This kind of tool is particularly interesting so as to help the decision makers to select the appropriate alternative and to plan the investments especially for developing countries, with important sanitary problems and severe budget restrictions.

Event-based quantification of emerging pollutant removal for an open stormwater retention basin - loads, efficiency and importance of uncertainties.

Up to now, emerging contaminants have not been further-studied in in-situ stormwater best management practices and especially in detention basins. In this article, the efficiency of a dry stormwater detention basin was investigated regarding the removal of 7 alkylphenols and alkylphenol ethoxylates, 9 polybrominated diphenyl ethers, 45 pesticides and bisphenol A. Concentrations of contaminants were obtained by chemical analysis on dissolved and particulate phase distinctly. The removal efficiency was assessed on total, dissolved and particulate phase accounting for the global chain of uncertainty with a 95% confidence interval. Results showed that pesticides (rather hydrophilic) are not trapped in the detention basin but are released contrarily to B209 which is mostly in particulate phase. Alkylphenols and alkylphenol ethoxylates are present in both phases and the efficiency is storm event-dependent. Uncertainty consideration in efficiency determination revealed efficiency data, usually presented by raw values are not relevant to conclude on the performance of a detention basin. In this case study, efficiency data with a 95% confidence interval indicate that only 35%, 50% and 41% of campaigns showed an impact (in trapping or releasing) of the detention basin on alkylphenols and ethoxylates, polybrominated diphenyl ethers and pesticides respectively.

Probing the limits of gate-based charge sensing.

Quantum computation requires a qubit-specific measurement capability to readout the final state of individual qubits. Promising solid-state architectures use external readout electrometers but these can be replaced by a more compact readout element, an in situ gate sensor. Gate-sensing couples the qubit to a resonant circuit via a gate and probes the qubit's radiofrequency polarizability. Here we investigate the ultimate performance of such a resonant readout scheme and the noise sources that limit its operation. We find a charge sensitivity of 37 µe Hz(-1/2), the best value reported for this technique, using the example of a gate sensor strongly coupled to a double quantum dot at the corner states of a silicon nanowire transistor. We discuss the experimental factors limiting gate detection and highlight ways to optimize its sensitivity. In total, resonant gate-based readout has advantages over external electrometers both in terms of reduction of circuit elements as well as absolute charge sensitivity.

Inhibitors of messenger RNA and protein synthesis affect differently serotonin arylalkylamine N-acetyltransferase activity in clock-controlled and non clock-controlled fish pineal.

The pineal organ of fish contains photoreceptor cells. In some species (e.g., pike) each photoreceptor is a cellular circadian system which contains a photoreceptive unit, the clock and an output unit. In others (e.g., trout) the clock is lacking. The main rhythmic output of the pineal photoreceptor is melatonin, an internal 'zeitgeber' of the organisms. The nocturnal rise in melatonin secretion results from an increase in the activity of the arylalkylamine-N-acetyltransferase (AA-NAT) which converts serotonin to N-acetylserotonin. In the present study we investigated the effects of transcription and translation inhibitors on AA-NAT activity in pike and trout pineal organs in culture. Cycloheximide, anisomycin, and puromycin inhibited the rise in AA-NAT activity observed during the first 2, 4 or 6 h of the dark phase, in both species. Actinomycin D was active only in the pike. Six hours of treatment during the first half of the night induced inhibition of AA-NAT activity, providing that forskolin (an adenylyl cyclase stimulator) was present in the culture medium. When the treatment was run for 3, 6 or 12 h, starting at midday of a 12L/12D cycle, basal and forskolin-stimulated AA-NAT activity (measured at midnight) were dramatically reduced. Such a treatment had no effect on trout AA-NAT activity. It is concluded that: (1) the dark-induced rise in AA-NAT activity and melatonin secretion are dependent on newly synthesized protein in both pike and trout pineal; (2) AA-NAT regulation takes place at the translational and post-translational levels in both species; (3) AA-NAT regulation occurs also at the transcriptional level in the pike, but not in the trout; and (4) the cAMP-dependent activation of AA-NAT requires transcription in the pike, not in the trout. The presence of a cell population acting as a circadian clock in the pike pineal, but not in the trout pineal, can explain the difference between these two species. Thus, we suggest that the clock mechanism operates at the genetic level in these cells. Further comparative studies between clock-controlled and non-clock-controlled pineals might prove interesting to demonstrate the difference between these two regulatory pathways.

Impact of viral hemorrhagic disease on a wild population of European rabbits in France.

An outbreak of rabbit viral hemorrhagic disease (RVHD) and of myxomatosis occurred in a free-living population of rabbits (Oryctolagus cuniculus) near Paris (France) in 1995. Annual mortality rates were 88% in adults and 99% in juveniles. There was no difference in mortality rates between males and females. Since most adults were protected with myxoma antibodies after May, they probably died of RVHD. Mortality lasted throughout the year despite high proportions of rabbits having developed myxomatosis and RVHD antibodies, which suggests that the combination of the two diseases and the immunosuppressive characteristics of myxoma virus could be responsible for the mortality caused by RVHD. The proportion of juveniles with RVHD antibodies increased with their weight. Seroconversion against RVHD occurred in spring and autumn.