Field quality in the twin aperture D2 dipoles for LHC under asymmetric excitation

Twin aperture D2 magnets are one of the several types of dipoles to be built by BNL for the interaction regions of LHC. To minimize the number of dipole correctors required in the interaction regions, D2 will also be used as part of the steering system. Consequently, the operating fields in the two apertures may differ by up to ~10at 7 TeV operation and ~33at injection in order to compensate for the strengths of the correctors that would otherwise be required. Such asymmetric excitation of the two apertures may induce undesirable field harmonics. The saturation behavior of various harmonics is studied using POISSON and OPERA-2D. It is shown that the changes in harmonics resulting from the anticipated asymmetry are within tolerable limits. (2 refs)

Superconducting magnets

Superconducting dipole magnets for high energy colliders are discussed. As an example, the magnets recently built for the Relativistic Heavy Ion Collider at Brookhaven are reviewed. Their technical performance and the cost for the industry-built production dipoles are given. The cost data is generalized in order to extrapolate the cost of magnets for a new machine

Unemployment, negative equity, and strategic default

Using new household-level data, we quantitatively assess the roles that job loss, negative equity, and wealth (including unsecured debt, liquid assets, and illiquid assets) play in default decisions. In sharp contrast to prior studies that proxy for individual unemployment status using regional unemployment rates, we find that individual unemployment is the strongest predictor of default. We find that individual unemployment increases the probability of default by 5 - 13 percentage points, ceteris paribus, compared with the sample average default rate of 3.9 percent. We also find that only 13.9 percent of defaulters have both negative equity and enough liquid or illiquid assets to make one month's mortgage payment. This finding suggests that "ruthless" or "strategic" default during the 2007 - 09 recession was relatively rare and that policies designed to promote employment, such as payroll tax cuts, are most likely to stem defaults in the long run rather than policies that temporarily modify mortgages

Can't pay or won't pay? Unemployment, negative equity, and strategic default

Prior research has found that job loss, as proxied for by regional unemployment rates, is a weak predictor of mortgage default. In contrast, using micro data from the PSID, this paper finds that job loss and adverse financial shocks are important determinants of mortgage default. Households with an unemployed head are approximately three times as likely to default as households with an employed head. Similarly, households that experience divorce, report large outstanding medical expenses, or have had any other severe income loss are much more likely to default. While household-level employment and financial shocks are important drivers of mortgage default, our analysis shows that the vast majority of financially distressed households do not default. More than 80 percent of unemployed households with less than one month of mortgage payment in savings are current on their payments. We argue that this has important implications for theoretical models of mortgage default as well as for loss mitigation policies. Finally, this paper provides some of the first direct evidence on the extent of strategic default. Wealth data suggest a limited scope for strategic default, with only one-third of underwater defaulters having enough liquid assets to cover one month´s mortgage payment

No interactions between heparin and atacicept, an antagonist of B cell survival cytokines.

The TNF family ligands, B cell activating factor of the TNF family (BAFF, also known as B lymphocyte stimulator, BLyS) and a proliferation-inducing ligand (APRIL), share the transmembrane activator and calcium-modulator and cyclophilin ligand (CAML)-interactor (TACI) as one of their common receptors. Atacicept, a chimeric recombinant TACI/IgG1-Fc fusion protein, inhibits both ligands. TACI and APRIL also bind to proteoglycans and to heparin that is structurally related to proteoglycans. It is unknown whether the portion of TACI contained in atacicept can bind directly to proteoglycans, or indirectly via APRIL, and whether this could interfere with the anti-coagulant properties of heparin. Binding of atacicept and APRIL to proteoglycan-positive cells was measured by FACS. Activities of heparin and atacicept were measured with activated factor Xa inhibition and cell-based assays. Effects of heparin on circulating atacicept was monitored in mice. Atacicept did not bind to proteoglycan-positive cells, but when complexed to APRIL could do so indirectly via APRIL. Multimers of atacicept obtained after exposure to cysteine or BAFF 60-mer bound directly to proteoglycans. Atacicept alone, or in complex with APRIL, or in a multimeric form did not interfere with heparin activity in vitro. Conversely, heparin did not influence inhibition of BAFF and APRIL by atacicept and did not change circulating levels of atacicept. Lack of detectable interference of APRIL-bound or free atacicept on heparin activity makes it unlikely that atacicept at therapeutic doses will interfere with the function of heparin in vivo