A Xenon Condenser with a Remote Liquid Storage Vessel

We describe the design and operation of a system for xenon liquefaction in which the condenser is separated from the liquid storage vessel. The condenser is cooled by a pulse tube cryocooler, while the vessel is cooled only by the liquid xenon itself. This arrangement facilitates liquid particle detector research by allowing easy access to the upper and lower flanges of the vessel. We find that an external xenon gas pump is useful for increasing the rate at which cooling power is delivered to the vessel, and we present measurements of the power and efficiency of the apparatus.Comment: 22 pages, 7 figures Corrected typos in authors lis

Efficient UC Commitment Extension with Homomorphism for Free (and Applications)

Homomorphic universally composable (UC) commitments allow for the sender to reveal the result of additions and multiplications of values contained in commitments without revealing the values themselves while assuring the receiver of the correctness of such computation on committed values. In this work, we construct essentially optimal additively homomorphic UC commitments from any (not necessarily UC or homomorphic) extractable commitment. We obtain amortized linear computational complexity in the length of the input messages and rate 1. Next, we show how to extend our scheme to also obtain multiplicative homomorphism at the cost of asymptotic optimality but retaining low concrete complexity for practical parameters. While the previously best constructions use UC oblivious transfer as the main building block, our constructions only require extractable commitments and PRGs, achieving better concrete efficiency and offering new insights into the sufficient conditions for obtaining homomorphic UC commitments. Moreover, our techniques yield public coin protocols, which are compatible with the Fiat-Shamir heuristic. These results come at the cost of realizing a restricted version of the homomorphic commitment functionality where the sender is allowed to perform any number of commitments and operations on committed messages but is only allowed to perform a single batch opening of a number of commitments. Although this functionality seems restrictive, we show that it can be used as a building block for more efficient instantiations of recent protocols for secure multiparty computation and zero knowledge non-interactive arguments of knowledge

A prototype liquid Argon Time Projection Chamber for the study of UV laser multi-photonic ionization

This paper describes the design, realization and operation of a prototype liquid Argon Time Projection Chamber (LAr TPC) detector dedicated to the development of a novel online monitoring and calibration system exploiting UV laser beams. In particular, the system is intended to measure the lifetime of the primary ionization in LAr, in turn related to the LAr purity level. This technique could be exploited by present and next generation large mass LAr TPCs for which monitoring of the performance and calibration plays an important role. Results from the first measurements are presented together with some considerations and outlook.Comment: 26 pages, 27 figure

Searching for energetic cosmic axions in a laboratory experiment: testing the PVLAS anomaly

Astrophysical sources of energetic gamma rays provide the right conditions for maximal mixing between (pseudo)scalar (axion-like) particles and photons if their coupling is as strong as suggested by the PVLAS claim. This is independent of whether or not the axion interaction is standard at all energies or becomes supressed in the extreme conditions of the stellar interior. The flux of such particles through the Earth could be observed using a metre long, Tesla strength superconducting solenoid thus testing the axion interpretation of the PVLAS anomaly. The rate of events in CAST caused by axions from the Crab pulsar is also estimated for the PVLAS-favoured parameters.Comment: 5 pages, 3 figur

Blood lactose after dairy product intake in healthy men.

The absence of a dedicated transport for disaccharides in the intestine implicates that the metabolic use of dietary lactose relies on its prior hydrolysis at the intestinal brush border. Consequently, lactose in blood or urine has mostly been associated with specific cases in which the gastrointestinal barrier is damaged. On the other hand, lactose appears in the blood of lactating women and has been detected in the blood and urine of healthy men, indicating that the presence of lactose in the circulation of healthy subjects is not incompatible with normal physiology. In this cross-over study we have characterised the postprandial kinetics of lactose, and its major constituent, galactose, in the serum of fourteen healthy men who consumed a unique dose of 800 g milk or yogurt. Genetic testing for lactase persistence and microbiota profiling of the subjects were also performed. Data revealed that lactose does appear in serum after dairy intake, although with delayed kinetics compared with galactose. Median serum concentrations of approximately 0·02 mmol/l lactose and approximately 0·2 mmol/l galactose were observed after the ingestion of milk and yogurt respectively. The serum concentrations of lactose were inversely correlated with the concentrations of galactose, and the variability observed between the subjects' responses could not be explained by the presence of the lactase persistence allele. Finally, lactose levels have been associated with the abundance of the Veillonella genus in faecal microbiota. The measurement of systemic lactose following dietary intake could provide information about lactose metabolism and nutrient transport processes under normal or pathological conditions

X-ray emission during the muonic cascade in hydrogen

We report our investigations of X rays emitted during the muonic cascade in hydrogen employing charge coupled devices as X-ray detectors. The density dependence of the relative X-ray yields for the muonic hydrogen lines (K_alpha, K_beta, K_gamma) has been measured at densities between 0.00115 and 0.97 of liquid hydrogen density. In this density region collisional processes dominate the cascade down to low energy levels. A comparison with recent calculations is given in order to demonstrate the influence of Coulomb deexcitation.Comment: 5 pages, Tex, 4 figures, submitted to Physical Review Letter

The patient's perspective of placebo use in daily practice: a qualitative study

QUESTIONS UNDER STUDY: The use of placebo outside of randomised controlled trials raises ethical and legal issues. So far, patients' perspectives have been considered only in quantitative studies. These studies did not distinguish between pure placebos (no pharmacological effect) and impure placebos (pharmacological ingredient, but no disease-specific effect). The aim of our study was to explore patients' conceptualisation, experiences and attitudes regarding the use of placebos in daily clinical practice. METHODS: Qualitative study with a convenience sample of 12 patients and semistructured interviews. The interviews were digitally recorded; full transcripts were obtained. The information was analysed in accordance with the qualitative content analysis method. RESULTS: The definition of placebo given by the participants mostly matched the common understanding of a pure placebo. Most participants supposed that placebos were mainly effective in diseases in which psychological influences play an important role. Furthermore, most participants believed that placebos themselves mainly worked via psychological effects. The acceptance of a hypothetical earlier use of a placebo depended on the success of the therapy. CONCLUSION: Patients were not aware of the differences between pure and impure placebos. Even regarding pure placebos, patients were more open than many physicians would expect. Trust between the patient and the general practitioner is an important element of the acceptance of a placebo. Appropriate communication could further increase the acceptance. Further research is needed to adapt the information given to the patient about possible placebo therapy

Neutrino oscillation physics at an upgraded CNGS with large next generation liquid Argon TPC detectors

The determination of the missing $U_{e3}$ element (magnitude and phase) of the PMNS neutrino mixing matrix is possible via the detection of \numu\to\nue oscillations at a baseline $L$ and energy $E$ given by the atmospheric observations, corresponding to a mass squared difference $E/L \sim \Delta m^2\simeq 2.5\times 10^{-3} eV^2$. While the current optimization of the CNGS beam provides limited sensitivity to this reaction, we discuss in this document the physics potential of an intensity upgraded and energy re-optimized CNGS neutrino beam coupled to an off-axis detector. We show that improvements in sensitivity to $\theta_{13}$ compared to that of T2K and NoVA are possible with a next generation large liquid Argon TPC detector located at an off-axis position (position rather distant from LNGS, possibly at shallow depth). We also address the possibility to discover CP-violation and disentangle the mass hierarchy via matter effects. The considered intensity enhancement of the CERN SPS has strong synergies with the upgrade/replacement of the elements of its injector chain (Linac, PSB, PS) and the refurbishing of its own elements, envisioned for an optimal and/or upgraded LHC luminosity programme.Comment: 37 pages, 20 figure

Neurocognitive function in patients with atrial fibrillation undergoing pulmonary vein isolation.

BACKGROUND Atrial fibrillation (AF) is associated with cognitive dysfunction. However, neurocognitive function in AF patients undergoing pulmonary vein isolation (PVI) has not been well studied. The aim of this analysis is to compare neurocognitive function in patients who did or did not undergo PVI. MATERIALS AND METHODS We used data from the Swiss Atrial Fibrillation Cohort study (Swiss-AF), a prospective, observational, multicenter study in Switzerland. Patients with documented AF were enrolled and data of 1,576 patients without history of PVI and with complete information on PVI status and neurocognitive function were used. Information on PVI was collected at baseline and during 1 year of follow-up. Neurocognitive testing was performed at baseline and after 1 year of follow-up, using the Montreal Cognitive Assessment (MoCA), trail making test (TMT) A and B, digit symbol substitution test (DSST) and semantic fluency test (SFT). To investigate the association of PVI with neurocognitive function, we use propensity score matching (1:3) and inverse probability of treatment weighting (IPTW). RESULTS The mean age of this population was 74 ± 8 years, 27.1% were women. Overall, 88 (5.5%) patients underwent PVI during 1 year of follow-up. Using ITPW (n = 1576), PVI was weakly associated with the MoCA score after adjusting for time since PVI, baseline MoCA score and other covariates (β (95%CI) 1.19 (0.05; 2.32), p = 0.04). In the propensity matched comparison (n = 352), there was no significant association between PVI and the MoCA score (β (95%CI) 1.04 (-0.19; 2.28), p = 0.1). There were no significant associations between PVI and cognitive function when using the TMT A and B, DSST or SFT independent of the method used. CONCLUSION In this population of AF patients, there was no consistent evidence of an association between PVI and neurocognitive function. CLINICAL TRIAL REGISTRATION [https://clinicaltrials.gov/], identifier [NCT02105844]

First results on light readout from the 1-ton ArDM liquid argon detector for dark matter searches

ArDM-1t is the prototype for a next generation WIMP detector measuring both the scintillation light and the ionization charge from nuclear recoils in a 1-ton liquid argon target. The goal is to reach a minimum recoil energy of 30\,keVr to detect recoiling nuclei. In this paper we describe the experimental concept and present results on the light detection system, tested for the first time in ArDM on the surface at CERN. With a preliminary and incomplete set of PMTs, the light yield at zero electric field is found to be between 0.3-0.5 phe/keVee depending on the position within the detector volume, confirming our expectations based on smaller detector setups.Comment: 14 pages, 10 figures, v2 accepted for publication in JINS