On-line high-precision carbon position-specific stable isotope analysis: a review

Since the first commercial availability of gas chromatographs coupled with a combustion furnace and an isotope ratio mass spectrometry in 1990, compound-specific stable isotope analysis of organic molecules has been at the origin of scientific breakthroughs in a wide range of research fields. The presence of non-reacting atoms, however, can mask changes in molecular stable isotopic signatures; position-specific isotope analysis (PSIA) is the study of intramolecular isotopic variations. After a brief consideration of the potential and prospect of this new level in isotopic studies, in this study, we review few existing custom-built systems for on-line PSIA using continuous flow isotope ratio mass spectrometry instrumentation and how researchers have addressed issues related to this technique. Molecular fragmentation processes observed and optimised for various molecules are also discussed for on-line PSIA, as it would provide information on their application to new compounds

Costs of Participation in the School Administration Manager (SAM) Process

Analyzes variations in school districts' implementation costs, by model, of the school administration manager process to help principals increase the time they spend on instructional leadership. Explores funding sources

Thermal expansion of the spin-1/2 Heisenberg-chain compound Cu(C4_4H4_4N2_2)(NO3_3)2_2

Compounds containing magnetic subsystems representing simple model spin systems with weak magnetic coupling constants are ideal candidates to test theoretical predictions for the generic behavior close to quantum phase transitions. We present measurements of the thermal expansion and magnetostriction of the spin-1/2-chain compound copper pyrazine dinitrate Cu(C$_4$H$_4$N$_2$)(NO$_3$)$_2$. Of particular interest is the low-temperature thermal expansion close to the saturation field $H_c \simeq 13.9 \mathrm{T}$, which defines a quantum phase transition from the gapless Luttinger liquid state to the fully saturated state with a finite excitation gap. We observe a sign change of the thermal expansion for the different ground states, and at the quantum critical point $H_c$ the low-temperature expansion approaches a $1/\sqrt{T}$ divergence. Thus, our data agree very well with the expected quantum critical behaviour.Comment: 4 pages, 3 figures; to appear in the proceedings of the ICM 09 held in Karlsruhe, German

Modelling the Evolution of Credit Spreads in the United States

The authors use Jarrow and Turnbull's (1995) reduced-form methodology to model the evolution of the term structure of interest rates in the United States for different credit classes and different industries. The authors also estimate a liquidity function for each credit class and industry. Using data from individual firms, the authors estimate the probability of default under the natural measure and compare it with the estimated default frequencies produced by KMV.Financial markets; Market structure and pricing

Default Dependence: The Equity Default Relationship

The paper examines three equity-based structural models to study the nonlinear relationship between equity and credit default swap (CDS) prices. These models differ in the specification of the default barrier. With cross-firm CDS premia and equity information, we are able to estimate and compare the three models. We find that the stochastic barrier model performs better than the constant and uncertain barrier models in terms of both in-sample fit and out-of-sample forecasting of CDS premia. In addition, we demonstrate a linkage between the default barrier, jump intensity, and barrier volatility estimated from our models and firm-specific variables related to default risk, such as credit ratings, equity volatility, and leverage ratios.Econometric and statistical methods; Financial markets

Structure and Magnetic Properties of a 1D Alternating Cu(II) Monomer―Paddlewheel Chain

One-dimensional metal–organic coordination polymers make up a class of compounds with potential towards the development of practical, new magnetic materials. Herein, a rare example of an ABBABB coupled linear chain comprised of alternating dicopper(II) tetraacetate units bridged to copper(II) acetate monomer units via axial η2:η1:µ2 coordinated acetate is reported. Examination of the structure, determined by small molecule X-ray crystallography, shows that each Cu(II) ion is in a dx2–y2 magnetic ground state. Magnetic susceptibility and magnetization data were collected and, consistent with the structural interpretation, demonstrate that the Cu(II) dimer (paddlewheel) exhibits classic antiferromagnetic exchange, while the S = 1/2 Cu(II) monomer is uncompensated in the ground state (low temperature regime.) Data were therefore fitted to a modified Bleaney-Bowers model, and results were consistent with the only other reported chain in this class for which magnetic data are available

Insuring the Healthy or Insuring the Sick? The Dilemma of Regulating the Individual Health Insurance Market -- Short Case Studies of Six States

Looks at a range of regulatory strategies used to make individual health insurance policies more accessible and affordable. Assesses the effectiveness of regulatory reforms in Iowa, Kansas, Kentucky, Massachusetts, New Jersey, and Washington