Market Discipline by Depositors: A Summary of the Theoretical and Empirical Arguments

Fifty-four banks failed in the first quarter of 1987, more than in any quarter since 1933. Because bank failures are linked to bank risk, most of the regulatory proposals offered to control the growing number of bank failures are designed to encourage depositors to exert market discipline on bank officers and directors, thereby decreasing bank risk and lowering the incidence of bank failure. For policies relying on depositor discipline to be effective, depositors\u27 assets must be exposed to some risk, so that depositors will have an incentive to check the soundness of the banks in which they have deposited their money. At present, however, bank failure policy uses federal bailouts and arranged mergers for most failing banks, providing essentially complete protection for all depositors, regardless of the size of their deposits. This policy reduces the effectiveness of depositor discipline. In addition, the policy removes the incentive for bank managers to limit risk-taking, in effect subsidizing poorly managed, risky banks, and increases the likelihood of bank failures

Prospects for probing the gluon density in protons using heavy quarkonium hadroproduction

We examine carefully bottomonia hadroproduction in proton colliders, especially focusing on the LHC, as a way of probing the gluon density in protons. To this end we develop some previous work, getting quantitative predictions and concluding that our proposal can be useful to perform consistency checks of the parameterization sets of different parton distribution functions.Comment: LaTeX, 14 pages, 6 EPS figure

Intravascular ultrasound aids in the performance of endovascular repair of abdominal aortic aneurysm

AbstractPurpose: The purpose of this retrospective review was to assess the accuracy of aortic measurements with intravascular ultrasound scan (IVUS) compared with computed tomographic (CT) scan and to assess the role of IVUS in the performance of endovascular repair of abdominal aortic aneurysms (AAAs). Methods: Seventy-eight patients undergoing repair of AAA with the AneuRx stent graft (Medtronic AVE, Inc, Santa Rosa, Calif) underwent measurement with CT scan and IVUS. The initial selection of stent graft size was made on the basis of the CT scan measurements, but the final decision for size was made on the basis of the IVUS measurements. Standard measurements of a phantom tube obtained with IVUS, CT scan, and digital caliper were also compared. Results: IVUS measurements of the phantom standard agreed closely with CT scan measurements. However, stent graft size initially selected with CT measurement was altered in 28% of cases on the basis of intraoperative IVUS measurements. No type I endoleaks were encountered in our series, and no aortic cuffs were necessary for endoleak repair. Conclusion: IVUS accurately measures the aorta for selection of stent grafts for endovascular repair of AAA and may prevent type I endoleaks and remedial procedures for their repair. (J Vasc Surg 2003;37:615-8

Rapid self-assembly of brush block copolymers to photonic crystals

The reduced chain entanglement of brush polymers over their linear analogs drastically lowers the energetic barriers to reorganization. In this report, we demonstrate the rapid self-assembly of brush block copolymers to nanostructures with photonic bandgaps spanning the entire visible spectrum, from ultraviolet (UV) to near infrared (NIR). Linear relationships were observed between the peak wavelengths of reflection and polymer molecular weights. This work enables “bottom-up” fabrication of photonic crystals with application-tailored bandgaps, through synthetic control of the polymer molecular weight and the method of self-assembly. These polymers could be developed into NIR-reflective paints, to combat the “urban heat island effect” due to NIR photon thermalization

Hole dynamics and photoemission in a t-J model for SrCu_2(BO_3)_2

The motion of a single hole in a t-J model for the two-dimensional spin-gap compound SrCu_2(BO_3)_2 is investigated. The undoped Heisenberg model for this system has an exact dimer eigenstate and shows a phase transition between a dimerized and a Neel phase at a certain ratio of the magnetic couplings. We calculate the photoemission spectrum in the disordered phase using a generalized spin-polaron picture. By varying the inter-dimer hopping parameters we find a cross-over between a narrow quasiparticle band regime known from other strongly correlated systems and free-fermion behavior. The hole motion in the Neel-ordered phase is also briefly considered.Comment: 4 pages, 3 fig

Optogenetic strategies to investigate neural circuitry engaged by stress

Optogenetic techniques have given researchers unprecedented access to the function of discrete neural circuit elements and have been instrumental in the identification of novel brain pathways that become dysregulated in neuropsychiatric diseases. For example, stress is integrally linked to the manifestation and pathophysiology of neuropsychiatric illness, including anxiety, addiction and depression. Due to the heterogeneous populations of genetically and neurochemically distinct neurons in areas such as the bed nucleus of the stria terminalis (BNST), as well as their substantial number of projections, our understanding of how neural circuits become disturbed after stress has been limited. Using optogenetic tools, we are now able to selectively isolate distinct neural circuits that contribute to these disorders and perturb these circuits in vivo, which in turn may lead to the normalization of maladaptive behavior. This review will focus on current optogenetic strategies to identify, manipulate, and record from discrete neural circuit elements in vivo as well as highlight recent optogenetic studies that have been utilized to parcel out BNST function

Stereocomplex Formation of Densely Grafted Brush Polymers

In this report, we explore the capability of macromolecules to interdigitate into densely grafted molecular brush copolymers. We demonstrate that by using the tendency for stereocomplexation between poly(l-lactide) and poly(d-lactide) as a driving force complementary linear polymers and brush copolymers can form a stereocomplex. However, stereocomplex formation between complementary brush copolymers is restricted and only partially observed when the side chains are of a critical molecular weight

Field dependent thermodynamics and Quantum Critical Phenomena in the dimerized spin system Cu2(C5H12N2)2Cl4

Experimental data for the uniform susceptibility, magnetization and specific heat for the material Cu2(C5H12N2)2Cl4 (abbreviated CuHpCl) as a function of temperature and external field are compared with those of three different dimerized spin models: alternating spin-chains, spin-ladders and the bilayer Heisenberg model. It is shown that because this material consists of weakly coupled spin-dimers, much of the data is insensitive to how the dimers are coupled together and what the effective dimensionality of the system is. When such a system is tuned to the quantum critical point by application of a field, the dimensionality shows up in the power-law dependences of thermodynamic quantities on temperature. We discuss the temperature window for such a quantum critical behavior in CuHpCl.Comment: Revtex, 5 pages, 4 figures (postscript

The Effect of the Pairing Interaction on the Energies of Isobar Analog Resonances in 112−124^{112-124}Sb and Isospin Admixture in 100−124^{100-124}Sn Isotopes

In the present study, the effect of the pairing interaction and the isovector correlation between nucleons on the properties of the isobar analog resonances (IAR) in $^{112-124}$Sb isotopes and the isospin admixture in $^{100-124}$Sn isotopes is investigated within the framework of the quasiparticle random phase approximation (QRPA). The form of the interaction strength parameter is related to the shell model potential by restoring the isotopic invariance of the nuclear part of the total Hamiltonian. In this respect, the isospin admixtures in the $^{100-124}$Sn isotopes are calculated, and the dependence of the differential cross section and the volume integral $J_{F}$ for the Sn($^{3}$He,t)Sb reactions at E($^{3}$He)$=200$ MeV occurring by the excitation of IAR on mass number A is examined. Our results show that the calculated value for the isospin mixing in the $^{100}$Sn isotope is in good agreement with Colo et al.'s estimates $(4-5$, and the obtained values for the volume integral change within the error range of the value reported by Fujiwara et al. (53$\pm$5 MeV fm$^{3}$). Moreover, it is concluded that although the differential cross section of the isobar analog resonance for the ($^{3}$He,t) reactions is not sensitive to pairing correlations between nucleons, a considerable effect on the isospin admixtures in $N\approx Z$ isotopes can be seen with the presence of these correlations.Comment: 16 pages, 5 EPS figures and 2 tables, Late

Anharmonic double-phonon excitations in the interacting boson model

Double-$\gamma$ vibrations in deformed nuclei are analyzed in the context of the interacting boson model. A simple extension of the original version of the model towards higher-order interactions is required to explain the observed anharmonicities of nuclear vibrations. The influence of three- and four-body interactions on the moments of inertia of ground- and $\gamma$-bands, and on the relative position of single-$\gamma$ and double-$\gamma$ bands is studied in detail. As an example of a realistic calculation, spectra and transitions of the highly $\gamma$-anharmonic nuclei $^{164}$Dy, $^{166}$Er, and $^{168}$Er are interpreted in this approach.Comment: 38 pages, TeX (ReVTeX). 15 ps figures. Submitted to Phys. Rev.