Full Counting Statistics of Multiple Andreev Reflections in incoherent diffusive superconducting junctions

We present a theory for the full distribution of current fluctuations in incoherent diffusive superconducting junctions, subjected to a voltage bias. This theory of full counting statistics of incoherent multiple Andreev reflections is valid for arbitrary applied voltage. We present a detailed discussion of the properties of the first four cumulants as well as the low and high voltage regimes of the full counting statistics. The work is an extension of the results of Pilgram and the author, Phys. Rev. Lett. 94, 086806 (2005).Comment: Included in special issue Spin Physics of Superconducting heterostructures of Applied Physics A: Materials Science & Processin

Multiple Andreev Reflection and Giant Excess Noise in Diffusive Superconductor/Normal-Metal/Superconductor Junctions

We have studied superconductor/normal metal/superconductor (SNS) junctions consisting of short Au or Cu wires between Nb or Al banks. The Nb based junctions display inherent electron heating effects induced by the high thermal resistance of the NS boundaries. The Al based junctions show in addition subharmonic gap structures in the differential conductance dI/dV and a pronounced peak in the excess noise at very low voltages V. We suggest that the noise peak is caused by fluctuations of the supercurrent at the onset of Josephson coupling between the superconducting banks. At intermediate temperatures where the supercurrent is suppressed a noise contribution ~1/V remains, which may be interpreted as shot noise originating from large multiple charges.Comment: 7 pages, 7 figures, extended versio

Barriers and strategies affecting the utilisation of primary preventive services for people with physical disabilities:a qualitative inquiry

Individuals with physical disabilities are less likely to utilise primary preventive healthcare services than the general population. At the same time they are at greater risk for secondary conditions and as likely as the general population to engage in health risk behaviours. This qualitative exploratory study had two principal objectives: (1) to investigate access barriers to obtaining preventive healthcare services for adults with physical disabilities and (2) to identify strategies to increase access to these services. We conducted five focus group interviews with adults (median age: 46) with various physically disabling conditions. Most participants were male Caucasians residing in Virginia, USA. Study participants reported a variety of barriers that prevented them from receiving the primary preventive services commonly recommended by the US Preventive Services Task Force. We used a health services framework to distinguish structural–environmental (to include inaccessible facilities and examination equipment) or process barriers (to include a lack of disability-related provider knowledge, respect, and skilled assistance during office visits). Participants suggested a range of strategies to address these barriers including disability-specific continuing education for providers, the development of accessible prevention-focused information portals for people with physical disabilities, and consumer self-education, and assertiveness in requesting recommended services. Study findings point to the need for a more responsive healthcare system to effectively meet the primary prevention needs of people with physical disabilities. The authors propose the development of a consumer- and provider-focused resource and information kit that reflects the strategies that were suggested by study participants

Subnuclear Localization and Cajal Body Targeting of Transcription Elongation Factor TFIIS in Amphibian Oocytes

We have examined the localization and targeting of the RNA polymerase II (pol II) transcription elongation factor TFIIS in amphibian oocyte nuclei by immunofluorescence. Using a novel antibody against Xenopus TFIIS the major sites of immunostaining were found to be Cajal bodies, nuclear organelles that also contain pol II. Small granular structures attached to lampbrush chromosomes were also specifically stained but the transcriptionally active loops were not. Similar localization patterns were found for the newly synthesized myc-tagged TFIIS produced after injection of synthetic transcripts into the cytoplasm. The basis of the rapid and preferential targeting of TFIIS to Cajal bodies was investigated by examining the effects of deletion and site-specific mutations. Multiple regions of TFIIS contributed to efficient targeting including the domain required for its binding to pol II. The localization of TFIIS in Cajal bodies, and in particular the apparent involvement of pol II binding in achieving it, offer further support for a model in which Cajal bodies function in the preassembly of the transcriptional machinery. Although our findings are therefore consistent with TFIIS playing a role in early events of the transcription cycle, they also suggest that this elongation factor is not generally required during transcription in oocytes