A Note on Credit-Worthiness Tests

Banks often have to determine the credit worthiness, i.e. the ability to repay the loan, of their customers ex-ante. According to the theory of imperfect diagnosis, it can be rational not to use an informative diagnosis result, even though it can be acquired without costs. We call this non-contingent behavior: The decision whether to grant a loan or not is independent of the diagnosis result. Hence, it can be rational to grant a loan to a particular applicant, even if the specific diagnosis result is negative. -- Banken müssen häufig vorab über die Kreditwürdigkeit ihrer Kunden entscheiden, also deren Fähigkeit, gewährte Kredite nebst Zinsen zurückzuzahlen. Gemäß der Theorie imperfekter Entscheidungen kann es rational sein, ein Signal selbst dann nicht bei der Entscheidung zu berücksichtigen, wenn es informativ und kostenlos verfügbar ist. Dieses Verhalten nennen wir "nichtkontingent": Die Entscheidung über die Kreditgewährung ist dann unabhängig vom Diagnoseergebnis. Demnach kann es sogar rational sein, einen Kredit zu gewähren, wenn das Diagnosesignal negativ ist.Diagnosis Theory,Imperfect Decision Making,Adverse Selection,Banks,Credit Rationing

Inhomogeneous nuclear spin polarization induced by helicity-modulated optical excitation of fluorine-bound electron spins in ZnSe

Optically-induced nuclear spin polarization in a fluorine-doped ZnSe epilayer is studied by time-resolved Kerr rotation using resonant excitation of donor-bound excitons. Excitation with helicity-modulated laser pulses results in a transverse nuclear spin polarization, which is detected as a change of the Larmor precession frequency of the donor-bound electron spins. The frequency shift in dependence on the transverse magnetic field exhibits a pronounced dispersion-like shape with resonances at the fields of nuclear magnetic resonance of the constituent zinc and selenium isotopes. It is studied as a function of external parameters, particularly of constant and radio frequency external magnetic fields. The width of the resonance and its shape indicate a strong spatial inhomogeneity of the nuclear spin polarization in the vicinity of a fluorine donor. A mechanism of optically-induced nuclear spin polarization is suggested based on the concept of resonant nuclear spin cooling driven by the inhomogeneous Knight field of the donor-bound electron.Comment: 12 pages, 11 figure

Strong seasonal differences of bacterial polysaccharide utilization in the North Sea over an annual cycle

Marine heterotrophic bacteria contribute considerably to global carbon cycling, in part by utilizing phytoplankton-derived polysaccharides. The patterns and rates of two different polysaccharide utilization modes - extracellular hydrolysis and selfish uptake - have previously been found to change during spring phytoplankton bloom events. Here we investigated seasonal changes in bacterial utilization of three polysaccharides, laminarin, xylan and chondroitin sulfate. Strong seasonal differences were apparent in mode and speed of polysaccharide utilization, as well as in bacterial community compositions. Compared to the winter month of February, during the spring bloom in May, polysaccharide utilization was detected earlier in the incubations and a higher portion of all bacteria took up laminarin selfishly. Highest polysaccharide utilization was measured in June and September, mediated by bacterial communities that were significantly different from spring assemblages. Extensive selfish laminarin uptake, for example, was detectible within a few hours in June, while extracellular hydrolysis of chondroitin was dominant in September. In addition to the well-known Bacteroidota and Gammaproteobacteria clades, the numerically minor verrucomicrobial clade Pedosphaeraceae could be identified as a rapid laminarin utilizer. In summary, polysaccharide utilization proved highly variable over the seasons, both in mode and speed, and also by the bacterial clades involved

Space Charge Limited 2-d Electron Flow between Two Flat Electrodes in a Strong Magnetic Field

An approximate analytic solution is constructed for the 2-d space charge limited emission by a cathode surrounded by non emitting conducting ledges of width Lambda. An essentially exact solution (via conformal mapping) of the electrostatic problem in vacuum is matched to the solution of a linearized problem in the space charge region whose boundaries are sharp due to the presence of a strong magnetic field. The current density growth in a narrow interval near the edges of the cathode depends strongly on Lambda. We obtain an empirical formula for the total current as a function of Lambda which extends to more general cathode geometries.Comment: 4 pages, LaTex, e-mail addresses: [email protected], [email protected]

Magneto-elastic coupling in La(Fe, Mn, Si)₁₃H<i>y</i> within the Bean-Rodbell model

First order magnetic phase transition materials present a large magnetocaloric effect around the transition temperature, where these materials usually undergo a large volume or structural change. This may lead to some challenges for applications, as the material may break apart during field change, due to high internal stresses. A promising magnetocaloric material is La(Fe, Mn, Si)13Hy, where the transition temperature can be controlled through the Mn amount. In this work we use XRD measurements to evaluate the temperature dependence of the unit cell volume with a varying Mn amount. The system is modelled using the Bean-Rodbell model, which is based on the assumption that the spin-lattice coupling depends linearly on the unit cell volume. This coupling is defined by the model parameter η, where for η > 1 the material undergoes a first order transition and for η  ≤ 1 a second order transition. We superimpose a Gaussian distribution of the transition temperature with a standard deviation σ T 0 , in order to model the chemical inhomogeneity. Good agreement is obtained between measurements and model with values of η  ∼ 1.8 and σ(T0) = 1.0 K