75,235 research outputs found
Saturation in ânonmagneticâ stainless steel
Scientific equipment often uses ânonmagneticâ stainless steel, relying on the steelâs nonmagnetic behavior to leave external magnetic fields unaltered. However, stainless steelâs permeability can rise significantly when it is welded or machined, possibly perturbing an external field. Such perturbations will diminish well above the stainless steelâs saturation point. The authors measured the permeability of both welded and machined 304 stainless steel as a function of an external magnetic field, and found that both saturate at fields of approximately 0.25 T
Sovereign debt (re)structuring-Where do we stand?
Argentinaâs debt default in 2001 moved the international community to launch initiatives to develop procedures for the orderly restructuring of unsustainable sovereign debt. These initiatives come against the backdrop of the increase in public debt in emerging market economies over the last decade, of large-scale fi nancial crises linked to the level or structure of sovereign debt and, a recent development, of several cases of sovereign default on international bonds. These developments pose two challenges. Firstly, the complexity of sovereign debt dynamics makes it necessary to strengthen international institutionsâ assessment capacity. The International Monetary Fund (IMF) has thus launched initiatives to improve the assessment of debt sustainability and balance sheet weaknesses. Secondly, the developments have prompted the re-examination of IMF facilities for managing debt crises. The absence of a clear framework in this area could create a moral hazard risk, as the international community could be tempted to avoid necessary restructuring by granting substantial fi nancial assistance. In practice, defining such a framework is complex, given that reforms in the area of restructuring influence the way in which debts are structured. In fact, the features of sovereign debt aim to reconcile two requirements: first, ensuring that the sovereign debtor honours the terms of the debt contract if it has the means to do so (ex ante efficiency); second, making sure that the cost of default is not excessive when the sovereign debtor is effectively unable to pay back (ex post effi ciency). The international community currently favours a market-based approach. Its first pillar is a result of the development and spread of collective action clauses (CAC), following the Quarles Report by the Group of 10. Incorporated into debt contracts, CAC aim to reduce the problems arising in inter-creditor co-ordination, by defi ning, in advance, the decision rules applicable in the event of re-negotiation. The âPrinciples for Stable Capital Flows and Fair Debt Restructuring in Emerging Marketsâ, whose defi nition was fostered notably by the Governor of the Banque de France and the Group of 20, form the second pillar. They supply guidelines for the parties involved to steer the exchange of information and facilitate co-ordination between debtors and creditors. The market-based approach is not exclusive of a formal regime, e.g. the IMFâs Sovereign Debt Restructuring Mechanism (SDRM), where such a regime is feasible. In the market-based approach, the IMF acts as an expert via the supply of information and analyses, and also as a âmonitorâ via the negotiation and monitoring of programmes. The provision of loans, which is in principle limited, aims mainly to facilitate renegotiation by giving credibility to the sovereignâs policy. By contrast, a more formal regime would suppose limiting IMF involvement, so as to guarantee the independence of the mechanism. Whatever the case, the efficiency of the overhauled restructuring framework, which is built on contractual provisions and general principles rather than on a formal regime, will depend on the Fundâs capacity to fully perform its three functions.
DCP-collected absolute target reflectance signatures assist accurate interpretation of ERTS-1 imagery
Data collection platforms (DCP's) are being used at a Black Hills, South Dakota, test site (MMC 226A) to record radiometric measurements needed to determine solar and atmospheric parameters that affect ERTS-1 multispectral scanner radiance measurements. A total of 72 channels of analog data transmitted from an unattended ground truth site via three DCP's at least six times a day. The system has operated with only minor problems since September, sending forth daily measurements of biophysical responses and atmospheric conditions. Comparisons of scene radiance data calculated from ERTS images with that measured on the ground show the image-measured values to be 35 percent higher for the green channel and 20 percent higher for the red channel for the same scene targets. Radiance values for channels 6 and 7 are nearly the same from the ground data and from the imagery
Spectral disentangling with Spectangular
The paper introduces the software Spectangular for spectral disentangling via
singular value decomposition with global optimisation of the orbital parameters
of the stellar system or radial velocities of the individual observations. We
will describe the procedure and the different options implemented in our
program. Furthermore, we will demonstrate the performance and the applicability
using tests on artificial data. Additionally, we use high-resolution spectra of
Capella to demonstrate the performance of our code on real-world data. The
novelty of this package is the implemented global optimisation algorithm and
the graphical user interface (GUI) for ease of use. We have implemented the
code to tackle SB1 and SB2 systems with the option of also dealing with
telluric (static) lines
Maturation of nuclear lamin A involves a specific carboxy-terminal trimming, which removes the polyisoprenylation site from the precursor; implications for the structure of the nuclear lamina.
Lamin A, a nuclear lamina protein of differentiated cells, is synthesized as a precursor of the mature molecule. Protein sequencing of the carboxyterminal 14 kDa fragment shows a lack of the last 18 residues predicted by cDNA sequencing. The carboxy-terminal proteolytic maturation explains previous biochemical results including the loss of the polyisoprenylation site now located to the CXXM motif at the end of the chain. This view and earlier results on lamin B predict multiple post-translational modifications shared by lamins A and B. While retained by lamin B, which is present in all cells, they are lost by maturation from lamin
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