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Probing dynamics of an electron-spin ensemble via a superconducting resonator

We study spin relaxation and diffusion in an electron-spin ensemble of nitrogen impurities in diamond at low temperature (0.25-1.2 K) and polarizing magnetic field (80-300 mT). Measurements exploit mode- and temperature-dependent coupling of hyperfine-split sub-ensembles to the resonator. Temperature-independent spin linewidth and relaxation time suggest that spin diffusion limits spin relaxation. Depolarization of one sub-ensemble by resonant pumping of another indicates fast cross-relaxation compared to spin diffusion, with implications on use of sub-ensembles as independent quantum memories.Comment: 5 pages, 5 figures, and Supplementary Information (2 figures

Modeling and Testing Superconducting Artificial CPW Lines Suitable for Parametric Amplification

Achieving amplification with high gain and quantum-limited noise is a difficult problem to solve. Parametric amplification using a superconducting transmission line with high kinetic inductance is a promising technology not only to solve this problem but also adding several benefits. When compared with other technologies, they have the potential of improving power saturation, achieving larger fractional bandwidths and operating at higher frequencies. In this type of amplifiers, selecting the proper transmission line is a key element in their design. Given current fabrication limitations, traditional lines such as coplanar waveguides (CPW), are not ideal for this purpose since it is difficult to make them with the proper characteristic impedance for good matching and slow-enough phase velocity for making them more compact. Capacitively-loaded lines, also known as artificial lines, are a good solution to this problem. However, few design rules or models have been presented to guide their accurate design. This fact is even more crucial considering that they are usually fabricated in the form of Floquet lines that have to be designed carefully to suppress undesired harmonics appearing in the parametric process. In this article we present, firstly, a new modelling strategy, based on the use of electromagnetic-simulation software, and, secondly, a first-principles model that facilitate and speed the design of CPW artificial lines and of Floquet lines made out of them. Then, we present comparisons with experimental results that demonstrate their accuracy. Finally, the theoretical model allows to predict the high-frequency behaviour of the artificial lines showing that they are good candidates for implementing parametric amplifiers above 100 GHz.Comment: 7 pages, 11 figures, submitted to IEEE Transactions on Applied Superconductivit

Composition and Potency Characterization of Mycobacterium avium subsp. paratuberculosis Purified Protein Derivatives

Mycobacterium avium subsp. paratuberculosis (MAP) purified protein derivatives (PPDs) are immunologic reagents prepared from cultured filtrates of the type strain. Traditional pro-duction consists of floating culture incubation at 37°C, organism inactivation by autoclaving, coarse filtration, and protein precipitation. Three traditional production PPDs were used in this study including lot 9801, which served as a reference and has been used in the field for decades. Alternative production PPDs (0902A and 0902B), in which the autoclaving step was removed, were also analyzed in this study. SDS-PAGE analysis revealed protein smearing in traditional PPDs, but distinct bands were observed in the alternative PPD preparations. Antibody bound distinct protein bands in the alternative PPDs by immunoblot analysis, whereas an immunoreactive smear was observed with the traditional PPDs. Mass spectrometry identified 194 proteins among three PPD lots representing the two different production methods, ten of which were present in all PPDs examined. Selected proteins identified by mass spectrometry were recombinantly expressed and purified from E. coli and evaluated by the guinea pig potency test. Seven recombinant proteins showed greater erythema as compared to the reference PPD lot 9801 in paired guinea pigs and were able to stimulate interferon-gamma production in blood from Johne’s positive animals. These results suggest that autoclaving culture suspensions is not a necessary step in PPD production and specific proteins could supplant the PPD antigen for intradermal skin testing procedures and for use as in-vitro assay reagents

Composition and Potency Characterization of Mycobacterium avium subsp. paratuberculosis Purified Protein Derivatives

Mycobacterium avium subsp. paratuberculosis (MAP) purified protein derivatives (PPDs) are immunologic reagents prepared from cultured filtrates of the type strain. Traditional pro-duction consists of floating culture incubation at 37°C, organism inactivation by autoclaving, coarse filtration, and protein precipitation. Three traditional production PPDs were used in this study including lot 9801, which served as a reference and has been used in the field for decades. Alternative production PPDs (0902A and 0902B), in which the autoclaving step was removed, were also analyzed in this study. SDS-PAGE analysis revealed protein smearing in traditional PPDs, but distinct bands were observed in the alternative PPD preparations. Antibody bound distinct protein bands in the alternative PPDs by immunoblot analysis, whereas an immunoreactive smear was observed with the traditional PPDs. Mass spectrometry identified 194 proteins among three PPD lots representing the two different production methods, ten of which were present in all PPDs examined. Selected proteins identified by mass spectrometry were recombinantly expressed and purified from E. coli and evaluated by the guinea pig potency test. Seven recombinant proteins showed greater erythema as compared to the reference PPD lot 9801 in paired guinea pigs and were able to stimulate interferon-gamma production in blood from Johne’s positive animals. These results suggest that autoclaving culture suspensions is not a necessary step in PPD production and specific proteins could supplant the PPD antigen for intradermal skin testing procedures and for use as in-vitro assay reagents

CSM-180 - An SQL Interface for the IFS/2 Knowledge-Baseserver: Release 2

A version of the IFS/2, known as the IFS/Q, has been designed to give direct support to SQL programs running on a host computer. This report gives detailed specifications of one external and two internal software and firmware interfaces which have been created for IFS/Q. Release 2 differs from Release 1 mainly in the Interface B details (see section 4). We have also tidied up the IFS/Q library procedures, which are described in a companion document - (see ref 9); for convenience this is included as Appendix B to this report

CLIMATIC VARIABILITY OF THE SOUTH PACIFIC OCEAN DURING 1900–2010 IN THE ENVIRONMENTAL RECORDS OF WEST ANTARCTICA

In this work, we present the climatic evolution of the South Pacific Ocean from 1900 to 2010 and its environmental influence over West Antarctica. We analyzed the sea surface temperature, mean sea level pressure, and meridional wind (at 850 hPa) of the South Pacific Ocean using ERA-20C reanalysis (European Center for Medium-Range Weather Forecasts) and compared these parameters with the regional temperature obtained indirectly (by proxy) from two ice cores from the West Antarctic ice sheet (Mount Johns and Ferrigno). The sea surface temperature increased in almost the entire South Pacific Ocean from 1900 to 2010; in the equatorial Pacific, it increased by 2.1 °C from 1916 to 1997, while in the middle latitudes of the South Pacific, it increased by 1.1 °C from 1923 to 2001. This increase occurred concurrently with a positive trend in the Southern Annular Mode and a change the mean sea level pressure anomaly from 1960 onwards. This atmospheric pressure increased at middle latitudes and decreased around Antarctica in the circumpolar low-pressure zone, strengthening the Amundsen Sea Low and changing the pattern of the meridional wind anomaly (at 850 hPa) between medium and high latitudes in the South Pacific. Furthermore, since 1960, a greater flow from north to south (onshore) has predominated from the southeast South Pacific to the north of West Antarctica. Such changes caused a reduction in the sea ice extent in the Amundsen and Bellingshausen Seas and an increase in average atmospheric temperature primarily in the coastal region of West Antarctica, as demonstrated by the Ferrigno ice core record. Conversely, the Mount Johns region did not show the same trend in atmospheric temperature, as it was influenced mainly by cold air masses from the Antarctic ice shee