Why do banks promise to pay par on demand?

We survey the theories of why banks promise to pay par on demand and examine evidence about the conditions under which banks have promised to pay the par value of deposits and banknotes on demand when holding only fractional reserves. The theoretical literature can be broadly divided into four strands: liquidity provision, asymmetric information, legal restrictions, and a medium of exchange. We assume that it is not zero cost to make a promise to redeem a liability at par value on demand. If so, then the conditions in the theories that result in par redemption are possible explanations of why banks promise to pay par on demand. If the explanation based on customers’ demand for liquidity is correct, payment of deposits at par will be promised when banks hold assets that are illiquid in the short run. If the asymmetric-information explanation based on the difficulty of valuing assets is correct, the marketability of banks’ assets determines whether banks promise to pay par. If the legal restrictions explanation of par redemption is correct, banks will not promise to pay par if they are not required to do so. If the transaction explanation is correct, banks will promise to pay par value only if the deposits are used in transactions. After the survey of the theoretical literature, we examine the history of banking in several countries in different eras: fourth-century Athens, medieval Italy, Japan, and free banking and money market mutual funds in the United States. We find that all of the theories can explain some of the observed banking arrangements, and none explain all of them

Obeticholic acid for the treatment of non-alcoholic steatohepatitis: interim analysis from a multicentre, randomised, placebo-controlled phase 3 trial

Background Non-alcoholic steatohepatitis (NASH) is a common type of chronic liver disease that can lead to cirrhosis. Obeticholic acid, a farnesoid X receptor agonist, has been shown to improve the histological features of NASH. Here we report results from a planned interim analysis of an ongoing, phase 3 study of obeticholic acid for NASH. Methods In this multicentre, randomised, double-blind, placebo-controlled study, adult patients with definite NASH,non-alcoholic fatty liver disease (NAFLD) activity score of at least 4, and fibrosis stages F2–F3, or F1 with at least oneaccompanying comorbidity, were randomly assigned using an interactive web response system in a 1:1:1 ratio to receive oral placebo, obeticholic acid 10 mg, or obeticholic acid 25 mg daily. Patients were excluded if cirrhosis, other chronic liver disease, elevated alcohol consumption, or confounding conditions were present. The primary endpointsfor the month-18 interim analysis were fibrosis improvement (≥1 stage) with no worsening of NASH, or NASH resolution with no worsening of fibrosis, with the study considered successful if either primary endpoint was met. Primary analyses were done by intention to treat, in patients with fibrosis stage F2–F3 who received at least one dose of treatment and reached, or would have reached, the month 18 visit by the prespecified interim analysis cutoff date. The study also evaluated other histological and biochemical markers of NASH and fibrosis, and safety. This study is ongoing, and registered with ClinicalTrials.gov, NCT02548351, and EudraCT, 20150-025601-6. Findings Between Dec 9, 2015, and Oct 26, 2018, 1968 patients with stage F1–F3 fibrosis were enrolled and received at least one dose of study treatment; 931 patients with stage F2–F3 fibrosis were included in the primary analysis (311 in the placebo group, 312 in the obeticholic acid 10 mg group, and 308 in the obeticholic acid 25 mg group). The fibrosis improvement endpoint was achieved by 37 (12%) patients in the placebo group, 55 (18%) in the obeticholic acid 10 mg group (p=0·045), and 71 (23%) in the obeticholic acid 25 mg group (p=0·0002). The NASH resolution endpoint was not met (25 [8%] patients in the placebo group, 35 [11%] in the obeticholic acid 10 mg group [p=0·18], and 36 [12%] in the obeticholic acid 25 mg group [p=0·13]). In the safety population (1968 patients with fibrosis stages F1–F3), the most common adverse event was pruritus (123 [19%] in the placebo group, 183 [28%] in the obeticholic acid 10 mg group, and 336 [51%] in the obeticholic acid 25 mg group); incidence was generally mild to moderate in severity. The overall safety profile was similar to that in previous studies, and incidence of serious adverse events was similar across treatment groups (75 [11%] patients in the placebo group, 72 [11%] in the obeticholic acid 10 mg group, and 93 [14%] in the obeticholic acid 25 mg group). Interpretation Obeticholic acid 25 mg significantly improved fibrosis and key components of NASH disease activity among patients with NASH. The results from this planned interim analysis show clinically significant histological improvement that is reasonably likely to predict clinical benefit. This study is ongoing to assess clinical outcomes

Correlation experiments in photon-induced nuclear fission

The nuclear fission process is highly complex and proceeds in heavy actinide and trans-actinide nuclei either spontaneously or induced by various reactions. Photon-induced reactions are particularly well understood due to the well-known electromagnetic interaction and because only dipole and electric quadrupole excitations are possible. This dissertation presents three developments for correlation experiments in photon-induced nuclear fission and demonstrates the feasibility of such correlation experiments with bremsstrahlung and monochromatic photons in the entrance channel, measuring the full fission-fragment mass distribution with ionization chambers. First, to increase the experimental luminosity for in-beam experiments a multi-target Frisch-grid ionization chamber (FGIC) has been developed. Second, the pulse-height defect (PHD) in different gas mixtures of Ar and CF4 has been determined relative to the reference gas P-10. Third, a positionsensitive FGIC has been constructed that allows the azimuthal fragment emission angle to be determined. The performance of the newly constructed multi-target FGIC, holding up to three targets simultaneously, was tested by an experiment utilizing bremsstrahlunginduced fission on 238U and 232Th at E0 = 8.5MeV, performed at the Darmstadt High-Intensity Photon Setup (DHIPS). Information on the mass, total kinetic energy (TKE) and polar angular distribution of the fission fragments was determined by means of the double kinetic energy technique and the drift-time method, whereas the average TKE of the fission fragments was calibrated relative to established data. The extracted pre-neutron mass distributions for 238U(γ,f) and 232Th(γ,f) are in good agreement with literature data. For the 232Th data an excellent agreement of the shape of TKE distribution with the shape of the literature data is observed. The measured angular distributions were fitted and parametrized by a function which describes the theoretically expected angular distribution. For 238U considerable E2 contributions are detected, whereas for 232Th a clear dipole pattern is evident. The assessment of Ar+CF4 mixtures as a counting-gas in ionization chambers was conducted by using a twin FGIC and fission fragments emitted in 252Cf(sf). As fission fragments emitted in 252Cf(sf) are well studied, a reliable comparison with established data as a basis for a PHD calibration procedure was possible. A universal function describing the PHD in different mixtures of Ar+CF4 was found and was used to calculate pre-neutron mass and TKE distributions. An excellent agreement between average pre-neutron fission-fragment masses measured in all counting-gases and literature is demonstrated with deviations smaller than 0.25 amu. The TKE distributions are in good agreement with established data, and calculated ⟨TKE⟩ values are, within uncertainties, in good agreement with the recommended value of 184.15MeV. To build a more compact multi-target FGIC, one may profit from the high stopping power of the Ar+CF4 mixtures. However, a pressure dependence in the pulse-height data showed that with regard to stopping power no benefit is gained by using Ar+CF4 instead of P-10. The performance of the position-sensitive FGIC was studied by investigating measured fission-fragment mass and TKE distributions as well as angular distributions from 238U(γ,f) at Eγ = 11.2MeV and Eγ = 8.0MeV excitation energy with linearly and circularly polarized γ-ray beams. The experiment was performed at the High Intensity γ-ray Source (HIγS), at the Triangle Universities Nuclear Laboratory (TUNL). Fission-fragment mass and TKE distributions were studied by applying the double kinetic energy technique, and angular distributions were extracted by applying the drift-time method and the read-out of the position-sensing anode structure. Calculated pre-neutron mass and TKE distributions were compared to literature data yielding good agreement. The presented fission-fragment yield as a function of TKE and pre-neutron mass number was used to extract information of fission-mode weights for the standard modes, super-long and super-short mode. A predominant standard-2 mode contribution as expected from theory is evident. The extracted super-short mode contribution of 0.1% has not been observed before in reference data and might be the first evidence of the existence of the super-short mode in light actinides. The fission-fragment polar angular distribution for 238U(γ⃗cir,f) at Eγ = 11.2MeV was analyzed for various mass splits in the fragment pre-neutron mass distribution and is in very good agreement to literature data. The evidence for a working position-sensitive structure is provided by the successful measurement of the fission-fragment azimuthal angle φ, which was measured in coincidence to the polar angle θ. For nearly 100% polarized photons, a distinct anisotropic distribution is observed, with a minimum at φ = 90◦. Normalized values for the contribution of the dipole fission channels are calculated as σγ,f (1−, 0) = 0.484 ± 0.007, σγ,f (1−, 1) = 0.439 ± 0.019 and σγ,f (1+, 1) = 0.078 ± 0.019, using the measured angular distribution coefficients. Prompt fission neutrons (PFN) were measured in coincidence with fission fragments from 238U using four liquid scintillator neutron detectors arranged around the FGIC. Neutron and γ-ray signals are distinguished by means of pulse-shape discrimination and time-of-flight information. The total neutron number detected in each liquid scintillator detector, respectively, is in the order of magnitude of previous estimations. This demonstrates the feasibility to measure prompt-neutron observables in a thin-target in-beam experiment

Performance of a twin position-sensitive Frisch-grid ionization chamber for photofission experiments

A position-sensitive twin Frisch-grid ionization chamber has been constructed for future photofission experiments using nearly monochromatic, linearly polarized gamma-ray beams. By exchanging the anode plates in the standard ionization chamber on both sides by an array of grid- and strip-anodes, which are rotated by 90° relative to each other and read out by means of resistive charge division, a position sensitivity is achieved that allows the azimuthal fragment emission angle and hence the fission axis orientation to be determined. The performance of this gaseous detector has been studied using the well-known 252Cf spontaneous fission process. The fission axis orientation could be determined relative to an arbitrary axis in space with a resolution better than 7° FWHM. Measured pre-neutron mass and total kinetic energy distributions are consistent with literature, which ensures that the mass and energy resolution for fission fragments is not affected by the position-sensitive structure

Performance of a twin position-sensitive Frisch-grid ionization chamber for photofission experiments

A position-sensitive twin Frisch-grid ionization chamber has been constructed for future photofission experiments using nearly monochromatic, linearly polarized gamma-ray beams. By exchanging the anode plates in the standard ionization chamber on both sides by an array of grid- and strip-anodes, which are rotated by 90° relative to each other and read out by means of resistive charge division, a position sensitivity is achieved that allows the azimuthal fragment emission angle and hence the fission axis orientation to be determined. The performance of this gaseous detector has been studied using the well-known 252Cf spontaneous fission process. The fission axis orientation could be determined relative to an arbitrary axis in space with a resolution better than 7° FWHM. Measured pre-neutron mass and total kinetic energy distributions are consistent with literature, which ensures that the mass and energy resolution for fission fragments is not affected by the position-sensitive structure

Tests of ionization chambers for future photofission experiments*

A recent set-up of a multi-cathode Frisch-grid ionization chamber and experimental results of a proof-of-principle experiment are presented. Preliminary data on the obtained polar angular and mass distributions as well as total kinetic energy of fission fragments produced in neutron-induced fission of 232Th and 238U are discussed that show that the chamber has been operated successfully. For the additional measurement of the azimuthal angular distribution, a design of segmented anodes has been tested. Preliminary data do not allow a suffcient reconstruction of the azimuthal angle

Tests of ionization chambers for future photofission experiments

A recent set-up of a multi-cathode Frisch-grid ionization chamber and experimental results of a proof-of-principle experiment are presented. Preliminary data on the obtained polar angular and mass distributions as well as total kinetic energy of fission fragments produced in neutron-induced fission of 232Th and 238U are discussed that show that the chamber has been operated successfully. For the additional measurement of the azimuthal angular distribution, a design of segmented anodes has been tested. Preliminary data do not allow a suffcient reconstruction of the azimuthal angle