Hedge funds, credit risk transfer and financial stability.

Over the past decade, central bankers and financial institution supervisors have sharpened their focus on the increasingly important role that private pools of investment funds play in global financial markets. The growth in these pools has contributed significantly to market efficiency and financial stability by expanding liquidity in many financial markets, improving price discovery, and, ultimately, lowering the costs of capital. Private investment pools and the alternative investment strategies they pursue have contributed to a signifi cant expansion of the global markets and have helped accelerate the evolution in traded credit products such as credit derivatives, collateralized debt obligations, and the securitization of an increasing array of traditionally illiquid assets. However, because of the lack of transparency and an established regime of supervision of these investment vehicles, policymakers and supervisors have become concerned about customer protection and the potential for systemic risk. This paper discusses some of the key issues confronting supervisors in light of the recent growth of private investment pools and the rapid developments in the area of credit risk transfer, with a particular focus on the implications of these trends regarding systemic risk and financial stability.

TTC5 is required to prevent apoptosis of acute myeloid leukemia stem cells

Using a screening strategy, we identified the tetratricopeptide repeat (TPR) motif protein, Tetratricopeptide repeat domain 5 (TTC5, also known as stress responsive activator of p300 or Strap) as required for the survival of human acute myeloid leukemia (AML) cells. TTC5 is a stress-inducible transcription cofactor known to interact directly with the histone acetyltransferase EP300 to augment the TP53 response. Knockdown (KD) of TTC5 induced apoptosis of both murine and human AML cells, with concomitant loss of clonogenic and leukemia-initiating potential; KD of EP300 elicited a similar phenotype. Consistent with the physical interaction of TTC5 and EP300, the onset of apoptosis following KD of either gene was preceded by reduced expression of BCL2 and increased expression of pro-apoptotic genes. Forced expression of BCL2 blocked apoptosis and partially rescued the clonogenic potential of AML cells following TTC5 KD. KD of both genes also led to the accumulation of MYC, an acetylation target of EP300, and the form of MYC that accumulated exhibited relative hypoacetylation at K148 and K157, residues targeted by EP300. In view of the ability of excess cellular MYC to sensitize cells to apoptosis, our data suggest a model whereby TTC5 and EP300 cooperate to prevent excessive accumulation of MYC in AML cells and their sensitization to cell death. They further reveal a hitherto unappreciated role for TTC5 in leukemic hematopoiesis

Modulation spectroscopy at non‐normal incidence with emphasis on the vacuum‐uv spectral region

Expressions are given to analyze modulation spectra taken at non‐normal incidence. These expressions are used to determine the optimum angle of incidence to maximize the signal‐to‐noise ratio. Significant improvements are shown to be obtained in the vacuum‐uv spectral region by making measurements at relatively large angles of incidence. We apply these expressions to evaluate the field‐induced change in the dielectric function for the 20.5–21.0‐eV core‐level doublet in GaP from Schottky‐barrier electroreflectance data. The line shape obtained is consistent with that of a field‐modulated M 0critical point modified by a Coulomb attraction between the core hole and the excited electron

Submicrosecond comparisons of time standards via the Navigation Technology Satellites (NTS)

An interim demonstration was performed of the time transfer capability of the NAVSTAR GPS system using a single NTS satellite. Measurements of time difference (pseudo-range) are made from the NTS tracking network and at the participating observatories. The NTS network measurements are used to compute the NTS orbit trajectory. The central NTS tracking station has a time link to the Naval Observatory UTC (USNO,MC1) master clock. Measurements are used with the NTS receiver at the remote observatory, the time transfer value UTC (USNO,MC1)-UTC (REMOTE, VIA NTS) is calculated. Intercomparisons were computed using predicted values of satellite clock offset and ephemeus

Electroreflectance of GaAs and GaP to 27 eV using synchrotron radiation

Electroreflectrance (ER) spectra of GaAs and GaP, taken with the Schottky-barrier method, exhibit to 27 eV the strong structural enchancement and high resolution characteristic of similar measurements below 6 eV. Above 20 eV, a new set of critical points is observed between the flat valence bands derived from the Ga 3d core levels and the local extrema of the sp3 conduction bands. The attained resolution, of the order of 100 meV, enables us to resolve clearly the spin-orbit splitting of 0.45 eV of the 3d-derived valence bands. The following critical-point energies have been determined in GaAs and GaP, respectively. sp3 valence conduction: E1′, 6.63 ± 0.05 eV, and 6.80 ± 0.05 eV; E1′+Δ1′, 6.97 ± 0.05 eV (GaAs only); E0\u27\u27(Γv15→Γc12), 10.53 eV, and 9.38 ± 0.1 eV; E0\u27\u27\u27(Γv15→Γc1), 8.33 ± 0.1 eV, and 10.27 ± 0.1 eV, E1\u27\u27, 9.5 ± 0.2 eV, and 10.7 ± 0.2 eV. E5, E6, and E7 structures are observed at 15.1, 16.7, and 17.9 eV in GaAs, and at 14.7, 16.1, and 18.6 eV in GaP. Relative values of 3d core to sp3 conduction-band matrix elements are estimated for several states and show that the lowest 3d core-level ER structures arise from transitions terminating at the Xc1conduction-band minimum. We calculate an exciton or core-hole interaction shift of 150 meV for GaP and 200 meV for GaAs, which indicates that core-hole effects are probably small for these materials. Spectral features with initial structure less than 100 meV in width are observed above 20 eV, showing that broadening effects are much smaller in this energy range than previously believed

Electroreflectance of GaSb from 0.6 to 26 eV

Schottky barrier electroreflectance spectra are reported for GaSb from 0.6 to 26 eV. Accurate energies are determined for a number of critical points between the sp3 and Ga−3d valence bands and the conduction bands. The energy of XV7 is shown to lie at least 3 eV below ΓV8. This is below the value obtained from local pseudopotential calculations and the x-ray photoemission assignments, but follows a trend previously established by nonlocal pseudopotential calculations for Ge and GaAs. The Ga 3d-XC6 exciton binding energy is of the order of 100 meV

Line shape and symmetry analysis of core-level electroreflectance spectra of GaP

No dependence of electroreflectance line shapes upon polarization direction or crystal orientation is found for any core-level electroreflectance structure from the Ga 3dv core levels to the conduction bands in GaP. Matrix-element effects that are responsible for anisotropy in sp3 valence-conduction-band electroreflectance spectra appear to be too weak to be detected in core-level spectra. The result may be general. The field-induced modulation line shape, Δε1, for the Ga 3dv32,52−Xc6 critical points is obtained from the dependence of the spectra and the generalized Seraphin coefficients upon angle of incidence. The line shape is further analyzed to obtain the Δε1 spectrum for Ga 3dv52−Xc6 alone. This procedure yields a spin-orbit splitting Δ3d=0.43±0.02 eV. A weighting of 0.65 ± 0.05 is also obtained for the j=32band relative to the j=52 band. This is in good agreement with the 4:6 ratio expected on d-band occupancy, showing that the matrix elements are also independent of j. The line shape of Δε1 is in good agreement with that predicted by the lifetime-broadened, Coulomb-enhanced Franz-Keldysh theory given by Blossey. The line shape shows a broadening of 160 meV for this transition, and a momentum matrix element about 1/3 as large as that characteristic of sp3 valence-conduction-band transitions

Ordering and Absolute Energies of the L6c and X6c Conduction Band Minima in GaAs

Resolved critical point structures in Schottky-barrier electroreflectance spectra of Ga3dV-sp3 conduction band transitions in the 20-22-eV range provide a direct proof that the L6C equivalent minima lie approximately 170±30 meVbelow the X6C minima in GaAs. This ordering, opposite to that assumed and apparently supported by previous experiments, is in fact consistent with these experiments and provides natural explanations for many formerly puzzling features of GaAs

Temperature Coefficients of Energy Separations between Ga 3d Core Levels and sp3 Valence-Conduction Bands in GaP

The measured temperature coefficients of the energy separations between the Ga 3d core levels and the top (Γ8V) and bottom (X6C) of the sp3 valence and conduction bands in GaP between 110 K and 295 K are (+1.0±0.5)×10−4 eV K−1and (-2.4±0.5)×10−4 eV K−1, respectively. They are described within experimental accuracy by the Debye-Waller, hydrostatic, self-energy, and spatially averaged screened-ion core potential interactions of the sp3 bands alone. No significant core-level contribution is observed