Analysis of General Power Counting Rules in Effective Field Theory

We derive the general counting rules for a quantum effective field theory (EFT) in $\mathsf{d}$ dimensions. The rules are valid for strongly and weakly coupled theories, and predict that all kinetic energy terms are canonically normalized. They determine the energy dependence of scattering cross sections in the range of validity of the EFT expansion. We show that the size of cross sections is controlled by the $\Lambda$ power counting of EFT, not by chiral counting, even for chiral perturbation theory ($\chi$PT). The relation between $\Lambda$ and $f$ is generalized to $\mathsf{d}$ dimensions. We show that the naive dimensional analysis $4\pi$ counting is related to $\hbar$ counting. The EFT counting rules are applied to $\chi$PT, low-energy weak interactions, Standard Model EFT and the non-trivial case of Higgs EFT.Comment: V2: more details and examples added; version published in journal. 17 pages, 4 figures, 2 table

Hybrid Superconducting Neutron Detectors

A new neutron detection concept is presented that is based on superconductive niobium (Nb) strips coated by a boron (B) layer. The working principle of the detector relies on the nuclear reaction 10B+n $\rightarrow$ $\alpha$+ 7Li , with $\alpha$ and Li ions generating a hot spot on the current-biased Nb strip which in turn induces a superconducting-normal state transition. The latter is recognized as a voltage signal which is the evidence of the incident neutron. The above described detection principle has been experimentally assessed and verified by irradiating the samples with a pulsed neutron beam at the ISIS spallation neutron source (UK). It is found that the boron coated superconducting strips, kept at a temperature T = 8 K and current-biased below the critical current Ic, are driven into the normal state upon thermal neutron irradiation. As a result of the transition, voltage pulses in excess of 40 mV are measured while the bias current can be properly modulated to bring the strip back to the superconducting state, thus resetting the detector. Measurements on the counting rate of the device are presented and the future perspectives leading to neutron detectors with unprecedented spatial resolutions and efficiency are highlighted.Comment: 8 pages 6 figure

Integrating Superconductive and Optical Circuits

We have integrated on oxidized silicon wafers superconductive films and Josephson junctions along with sol-gel optical channel waveguides. The fabrication process is carried out in two steps that result to be solid and non-invasive. It is demonstrated that 660 nm light, coupled from an optical fibre into the channel sol-gel waveguide, can be directed toward superconducting tunnel junctions whose current-voltage characteristics are affected by the presence of the radiation. The dependence of the change in the superconducting energy gap under optical pumping is discussed in terms of a non-equilibrium superconductivity model.Comment: Document composed of 7 pages of text and 3 figure

Permeation of Ternary Mixture Containing H2S, CO2 and CH4 in Aquivion® Perfluorosulfonic Acid (PFSA) Ionomer Membranes

Aquivion (R) E87-12S Perfluorosulfonated acid ionomer material (PFSA) has been studied as a membrane technology for natural gas sweetening from CO2 , H2S due to its interesting chemical and mechanical stability and good separation performance for polar compounds in humid environments. In the present work, permeation of the H2S/CO2/CH4 ternary mixture in this short-side PFSA chain was investigated at pressures up to 10 bar, temperatures up to 50 degrees C, and in a range of relative humidity (RH) from 20% to 90%. The results obtain confirm the strong dependence of Aquivion (R) on water activity and temperature, and its ability to separate gases based on their water solubility without substantial differences between pure and mixed gas experiments. Indeed, even when tested in ternary mixture, the permeation behavior remains similar to that observed for pure components and binary mixtures. In particular, the permeability of H2S is higher than that of CO(2 )and methane CH4, reaching values of 500 Barrer at 50 degrees C and 80% RH, against 450 and 23 Barrer for the other two gases respectively. Additionally, when tested at higher pressures of up to 10 bar under humid conditions, the membrane properties remained largely unchanged, thus confirming the overall stability and durability of Aquivion (R) E87-12S in acid environments

Multiple Components in Narrow Planetary Rings

The phase-space volume of regions of regular or trapped motion, for bounded or scattering systems with two degrees of freedom respectively, displays universal properties. In particular, drastic reductions in the volume (gaps) are observed at specific values of a control parameter. Using the stability resonances we show that they, and not the mean-motion resonances, account for the position of these gaps. For more degrees of freedom, exciting these resonances divides the regions of trapped motion. For planetary rings, we demonstrate that this mechanism yields rings with multiple components.Comment: 4 pages, 7 figures (some in colors

Double beta decay to excited states of daughter nuclei

In this paper we review results obtained in the searches of double beta decays to excited states of the daughter nuclei and illustrate the related experimental techniques. In particular, we describe in some detail the only two cases in which the transition has been observed; that is the 2β^− (0^+ → 0^+_1 ) decay of 100Mo and 150Nd nuclides. Moreover, the most significant results in terms of lower limits on the half-life are also summarized

Lung transplantation in patients 70 years old or older: Have outcomes changed after implementation of the lung allocation score?

ObjectiveThe objective of the present study was to evaluate whether the outcomes of lung transplantation in patients aged 70 years or older have changed after implementation of the lung allocation score in May 2005.MethodsPatients aged 70 years or older undergoing primary lung transplantation from 1995 to 2009 were identified from the United Network for Organ Sharing registry. The primary stratification was the pre-lung allocation score era versus lung allocation score era. Risk-adjusted multivariate Cox regression and Kaplan-Meier analyses were conducted to evaluate the effect of age 70 years or older on 1-year post-transplant mortality compared with a reference cohort of patients aged 60 to 69 years.ResultsOf the overall 15,726 adult lung transplantation patients in the study period, 225 (1.4%) were 70 years old or older and 4634 (29.5%) were 60 to 69 years old. The patients aged 70 years or older were a larger cohort of overall lung transplantation patients in the lung allocation score era compared with before the lung allocation score era (3.1% vs 0.3%, P < .001). In the risk-adjusted Cox analysis, age 70 years or older was a significant risk factor for 1-year post-lung transplantation mortality in the pre-lung allocation score era (hazard ratio, 2.00; 95% confidence interval, 1.10-3.62, P = .02) but not in the lung allocation score era (hazard ratio, 1.02; 95% confidence interval, 0.71-1.46; P = .92). Similarly, Kaplan-Meier 1-year survival was significantly reduced in patients 70 years old or older versus 60 to 69 years old in the pre-lung allocation score era (56.7% vs 76.3%, P = .006) but not in the lung allocation score era (79.0% vs 80.0%, P = .72).ConclusionsRecipients aged 70 years or older were a larger proportion of overall lung transplantation patients after implementation of the lung allocation score. Although associated with significantly increased post-lung transplantation mortality in the pre-lung allocation score era, age 70 years or older is currently associated with outcomes comparable to those of patients aged 60 to 69 years. Therefore, age 70 years or older should not serve as an absolute contraindication to lung transplantation in the lung allocation score era