Final state effects on superfluid 4^{\bf 4}He in the deep inelastic regime

A study of Final State Effects (FSE) on the dynamic structure function of superfluid $^4$He in the Gersch--Rodriguez formalism is presented. The main ingredients needed in the calculation are the momentum distribution and the semidiagonal two--body density matrix. The influence of these ground state quantities on the FSE is analyzed. A variational form of $\rho_2$ is used, even though simpler forms turn out to give accurate results if properly chosen. Comparison to the experimental response at high momentum transfer is performed. The predicted response is quite sensitive to slight variations on the value of the condensate fraction, the best agreement with experiment being obtained with $n_0=0.082$. Sum rules of the FSE broadening function are also derived and commented. Finally, it is shown that Gersch--Rodriguez theory produces results as accurate as those coming from other more recent FSE theories.Comment: 20 pages, RevTex 3.0, 11 figures available upon request, to be appear in Phys. Rev.

Development of NOx Sensors for Heavy Vehicle Applications

The primary gaseous pollutants (excluding CO{sub 2}) produced by combustion of low-sulfur diesel fuel oxides of nitrogen (NO{sub x}), carbon monoxide (CO), and hydrocarbons (C{sub y}H{sub z}). The last two of these can be readily ameliorated by an oxidation catalyst in the O{sub 2}-rich environment of diesel exhaust but NO{sub x} can not.[1] For this reason NO{sub x} remediation strategies such as selective catalytic reduction (SCR) [2, 3] and the lean NO{sub x} trap (LNT) [4, 5] are being actively pursued. The ideal implementation of these strategies would employ NO{sub x} sensors to control reagent injection in the case of SCR and trap regeneration in the case of LNT. Two different NO{sub x} sensors for this application are at or near commercialization: An amperometric NO{sub x} sensor developed by NGK [6] and a 'mixed potential' NO{sub x} sensor developed by Riken [7]. The NGK sensor works by passing the sampled exhaust through a series of two chambers. In the first chamber O{sub 2} is pumped from the exhaust and in the second, NO{sub x} is decomposed electrochemically and the current from this decomposition is measured in order to determine [NO{sub x}]. Since the NO{sub x} concentrations can be small, on the 10's of ppm levels, the currents produced by decomposing the NO{sub x} can be small and difficult to measure accurately. The Riken sensor functions by passing the exhaust over a 'conversion electrode' that converts the NO{sub x} to NO{sub 2}. This NO{sub 2} is then sensed by a mixed potential sensing element.[8-10] Researchers at Ford evaluated the NGK sensor and observed the above shortcoming (poor for low [NO{sub x}]) as well as others [11] (e.g., asymmetric response to NO vs. NO{sub 2}) and were unable to obtain samples of the Riken sensor. Therefore a CRADA was initiated between Ford an ORNL to investigate the development of NO{sub x} sensors for diesel exhaust applications

Beyond the binary collision approximation for the large-qq response of liquid 4^4He

We discuss corrections to the linear response of a many-body system beyond the binary collision approximation. We first derive for smooth pair interactions an exact expression of the response $\propto 1/q^2$, considerably simplifying existing forms and present also the generalization for interactions with a strong, short-range repulsion. We then apply the latter to the case of liquid $^4$He. We display the numerical influence of the $1/q^2$ correction around the quasi-elastic peak and in the low-intensity wings of the response, far from that peak. Finally we resolve an apparent contradiction in previous discussions around the fourth order cumulant expansion coefficient. Our results prove that the large-$q$ response of liquid $^4$He can be accurately understood on the basis of a dynamical theory.Comment: 19 p. Figs. available on reques

Mortality in people with coeliac disease: Long-term follow-up from a Scottish cohort

Background: Few studies have determined the very long-term mortality risks in adult and childhood-diagnosed coeliac disease. Objective: We quantified mortality risks in coeliac disease and determined whether age at diagnosis, or time following diagnosis, modified these risks. Methods: Standardised mortality ratios were determined using data from a cohort of 602 coeliac patients assembled between 1979�1983 from Lothian, Scotland, and followed up from 1970�2016. Results: All-cause mortality was 43 higher than in the general population. Excess deaths were primarily from haematological malignancies (standardised mortality ratio, 4.77) and external causes (standardised mortality ratio, 2.62) in adult and childhood-diagnosed cases respectively. Mortality risks declined steadily with time in adult-diagnosed cases (standardised mortality ratio, 4.85 in first year compared to 0.97, 25 years post-diagnosis). Beyond 15 years, this group had a significantly reduced risk of any malignancy (standardised mortality ratio, 0.57 (95 confidence interval: 0.33�0.92)). In contrast, for childhood-diagnosed cases an increased risk existed beyond 25 years (standardised mortality ratio, 2.24). Conclusions: Adult-diagnosed coeliac patients have a temporarily increased mortality risk mainly from malignant lymphomas and a decreased risk of any malignancy beyond 15 years post-diagnosis. In contrast, childhood-diagnosed cases are at an increased risk of mortality mainly from external causes, and have long-term mortality risks that requires further investigation. © Author(s) 2018

Determination of Coal Permeability Using Pressure Transient Methods

Coalbed methane is a significant natural resource in the Appalachian region. It is believed that coalbed methane production can be enhanced by injection of carbon dioxide into coalbeds. However, the influence of carbon dioxide injection on coal permeability is not yet well understood. Competitive sorption of carbon dioxide and methane gases onto coal is a known process. Laboratory experiments and limited field experience indicate that coal will swell during sorption of a gas and shrink during desorption of a gas. The swelling and shrinkage may change the permeability of the coal. In this study, the permeability of coal was determined by using carbon dioxide as the flowing fluid. Coal samples with different dimensions were prepared for laboratory permeability tests. Carbon dioxide was injected into the coal and the permeability was determined by using pressure transient methods. The confining pressure was variedto cover a wide range of depths. The permeability was also determined as a function of exposure time of carbon dioxide while the confining stress was kept constant. CT scans were taken before and after the introduction of carbon dioxide. Results show that the porosity and permeability of the coal matrix was very low. The paper presents experimental data and theoretical aspects of the flow of carbon dioxide through a coal sample during pressure transient tests. The suitability of the pressure transient methods for determining permeability of coal during carbon dioxide injection is discussed in the paper

Randomness Increases Order in Biological Evolution

n this text, we revisit part of the analysis of anti-entropy in Bailly and Longo (2009} and develop further theoretical reflections. In particular, we analyze how randomness, an essential component of biological variability, is associated to the growth of biological organization, both in ontogenesis and in evolution. This approach, in particular, focuses on the role of global entropy production and provides a tool for a mathematical understanding of some fundamental observations by Gould on the increasing phenotypic complexity along evolution. Lastly, we analyze the situation in terms of theoretical symmetries, in order to further specify the biological meaning of anti-entropy as well as its strong link with randomness

Factorization of integrals, defining the beta-function, into integrals of total derivatives in N=1 SQED, regularized by higher derivatives

Some calculations in supersymmetric theories, made with the higher derivative regularization, show that the beta-function is given by integrals of total derivatives. This is qualitatively explained for the N=1 supersymmetric electrodynamics in all orders.Comment: 14 page

Low Q^2 Jet Production at HERA and Virtual Photon Structure

The transition between photoproduction and deep-inelastic scattering is investigated in jet production at the HERA ep collider, using data collected by the H1 experiment. Measurements of the differential inclusive jet cross-sections dsigep/dEt* and dsigmep/deta*, where Et* and eta* are the transverse energy and the pseudorapidity of the jets in the virtual photon-proton centre of mass frame, are presented for 0 < Q2 < 49 GeV2 and 0.3 < y < 0.6. The interpretation of the results in terms of the structure of the virtual photon is discussed. The data are best described by QCD calculations which include a partonic structure of the virtual photon that evolves with Q2.Comment: 20 pages, 5 Figure

Hadron Production in Diffractive Deep-Inelastic Scattering

Characteristics of hadron production in diffractive deep-inelastic positron-proton scattering are studied using data collected in 1994 by the H1 experiment at HERA. The following distributions are measured in the centre-of-mass frame of the photon dissociation system: the hadronic energy flow, the Feynman-x (x_F) variable for charged particles, the squared transverse momentum of charged particles (p_T^{*2}), and the mean p_T^{*2} as a function of x_F. These distributions are compared with results in the gamma^* p centre-of-mass frame from inclusive deep-inelastic scattering in the fixed-target experiment EMC, and also with the predictions of several Monte Carlo calculations. The data are consistent with a picture in which the partonic structure of the diffractive exchange is dominated at low Q^2 by hard gluons.Comment: 16 pages, 6 figures, submitted to Phys. Lett.

Energy Flow in the Hadronic Final State of Diffractive and Non-Diffractive Deep-Inelastic Scattering at HERA

An investigation of the hadronic final state in diffractive and non--diffractive deep--inelastic electron--proton scattering at HERA is presented, where diffractive data are selected experimentally by demanding a large gap in pseudo --rapidity around the proton remnant direction. The transverse energy flow in the hadronic final state is evaluated using a set of estimators which quantify topological properties. Using available Monte Carlo QCD calculations, it is demonstrated that the final state in diffractive DIS exhibits the features expected if the interaction is interpreted as the scattering of an electron off a current quark with associated effects of perturbative QCD. A model in which deep--inelastic diffraction is taken to be the exchange of a pomeron with partonic structure is found to reproduce the measurements well. Models for deep--inelastic $ep$ scattering, in which a sizeable diffractive contribution is present because of non--perturbative effects in the production of the hadronic final state, reproduce the general tendencies of the data but in all give a worse description.Comment: 22 pages, latex, 6 Figures appended as uuencoded fil