Current fluctuations near to the 2D superconductor-insulator quantum critical point

Systems near to quantum critical points show universal scaling in their response functions. We consider whether this scaling is reflected in their fluctuations; namely in current-noise. Naive scaling predicts low-temperature Johnson noise crossing over to noise power $\propto E^{z/(z+1)}$ at strong electric fields. We study this crossover in the metallic state at the 2d z=1 superconductor/insulator quantum critical point. Using a Boltzmann-Langevin approach within a 1/N-expansion, we show that the current noise obeys a scaling form $S_j=T \Phi[T/T_{eff}(E)]$ with $T_{eff} \propto \sqrt{E}$. We recover Johnson noise in thermal equilibrium and $S_j \propto \sqrt{E}$ at strong electric fields. The suppression from free carrier shot noise is due to strong correlations at the critical point. We discuss its interpretation in terms of a diverging carrier charge $\propto 1/\sqrt{E}$ or as out-of-equilibrium Johnson noise with effective temperature $\propto \sqrt{E}$.Comment: 5 page

Community responses to seawater warming are conserved across diverse biological groupings and taxonomic resolutions

Temperature variability is a major driver of ecological pattern, with recent changes in average and extreme temperatures having significant impacts on populations, communities and ecosystems. In the marine realm, very few experiments have manipulated temperature in situ, and current understanding of temperature effects on community dynamics is limited. We developed new technology for precise seawater temperature control to examine warming effects on communities of bacteria, microbial eukaryotes (protists) and metazoans. Despite highly contrasting phylogenies, size spectra and diversity levels, the three community types responded similarly to seawater warming treatments of +3°C and +5°C, highlighting the critical and overarching importance of temperature in structuring communities. Temperature effects were detectable at coarse taxonomic resolutions and many taxa responded positively to warming, leading to increased abundances at the community-level. Novel field-based experimental approaches are essential to improve mechanistic understanding of how ocean warming will alter the structure and functioning of diverse marine communities

Josephson effects in MgB2 meta masked ion damage junctions

Ion beam damage combined with nanoscale focused ion beam direct milling was used to create manufacturable SNS type Josephson junctions in 100 nm thick MgB$_{2}$ with T$_{C}$ of 38 K. The junctions show non-hysteretic current - voltage characteristics between 36 and 4.2 K. Experimental evidence for the dc and ac Josephson effects in MgB$_{2}$ metal masked ion damage junctions are presented. This technique is particularly useful for prototyping devices due to its simplicity and flexibility of fabrication and has a great potential for high-density integration.Comment: 12 pages, 4 figures, RevTeX4, submitted to AP

Professional Social Work Supervision: The Relationship with Social Worker Retention and Self-Efficacy

Licensed social workers offer services including mental health, case management, hospice and palliative care, and community-based support services. However, research is limited regarding dynamics that promote social worker retention and continuous social service provision. Using self-efficacy theory, this study intended to examine relationships between supervision satisfaction, supervisor characteristics, employee self-efficacy, and retention among licensed social workers. This study was based on secondary data analysis and involved using a cross-sectional correlational survey design. Secondary data were retrieved from the National Association of Social Work Center for Workforce Studies. Licensed social workers were asked questions involving their satisfaction with supervision received, profession of supervisor, plans to remain within the profession, and their career as a licensed social worker. Availability of supervision and satisfaction with support and guidance received from supervisors had a significant relationship with level of self-efficacy. Other findings indicated no association between supervisor discipline and self-efficacy; therefore, it can be assumed that licensed social worker self-efficacy is related to availability of supervision and satisfaction with support and guidance received from supervisors, but not necessarily the profession of supervisors. Results of this study will contribute to knowledge regarding retention of licensed social workers and dynamics related to supervision within the social work profession

Tumor-derived exosomes confer antigen-specific immunosuppression in a murine delayed-type hypersensitivity model

Exosomes are endosome-derived small membrane vesicles that are secreted by most cell types including tumor cells. Tumor-derived exosomes usually contain tumor antigens and have been used as a source of tumor antigens to stimulate anti-tumor immune responses. However, many reports also suggest that tumor-derived exosomes can facilitate tumor immune evasion through different mechanisms, most of which are antigen-independent. In the present study we used a mouse model of delayed-type hypersensitivity (DTH) and demonstrated that local administration of tumor-derived exosomes carrying the model antigen chicken ovalbumin (OVA) resulted in the suppression of DTH response in an antigen-specific manner. Analysis of exosome trafficking demonstrated that following local injection, tumor-derived exosomes were internalized by CD11c+ cells and transported to the draining LN. Exosome-mediated DTH suppression is associated with increased mRNA levels of TGF-β1 and IL-4 in the draining LN. The tumor-derived exosomes examined were also found to inhibit DC maturation. Taken together, our results suggest a role for tumor-derived exosomes in inducing tumor antigen-specific immunosuppression, possibly by modulating the function of APCs. © 2011 Yang et al

Production of α1,3-galactosyltransferase-deficient pigs

The enzyme α1,3-galactosyltransferase (α1,3GT or GGTA1) synthesizes α1,3galactose (α1,3Gal) epitopes (Galα1,3Galβ1,4GlcNAc-R), which are the major xenoantigens causing hyperacute rejection in pig-to-human xenotransplantation. Complete removal of α1,3Gal from pig organs is the critical step toward the success of xenotransplantation. We reported earlier the targeted disruption of one allele of the α1,3GT gene in cloned pigs. A selection procedure based on a bacteria[toxin was used to select for cells in which the second allele of the gene was knocked out. Sequencing analysis demonstrated that knockout of the second allele of the α1,3GT gene was caused by a T-to-G single point mutation at the second base of exon 9, which resulted in inactivation of the α1,3GT protein. Four healthy α1,3GT double-knockout female piglets were produced by three consecutive rounds of cloning. The piglets carrying a point mutation in the α1,3GT gene hold significant value, as they would allow production of α1,3Gal-deficient pigs free of antibiotic-resistance genes and thus have the potential to make a safer product for human use

Measurement of Viscosity in Liquids Using Reflection Coefficient: Phase Difference Method

Measurement of viscosity of fluids is a critical parameter in determining the state of the fluid (ie. edible products), and the state of the forming solid (ie. molten metals and glasses). Experiments to measure viscosity using ultrasound, have been carried out since as early as 1951 [1]. Ultrasound has potentially offered a non-invasive, in-line method of property and process monitoring [2,3]. Early research has demonstrated that viscosity measurement can be accomplished by ultrasound using different linear and nonlinear techniques [4]. This paper is devoted to furthering the technique called shear reflectance method [5]

Echo in Optical Lattices: Stimulated Revival of Breathing Oscillations

We analyze a stimulated revival (echo) effect for the breathing modes of the atomic oscillations in optical lattices. The effect arises from the dephasing due to the weak anharmonicity being partly reversed in time by means of additional parametric excitation of the optical lattice. The shape of the echo response is obtained by numerically simulating the equation of motion for the atoms with subsequent averaging over the thermal initial conditions. A qualitative analysis of the phenomenon shows that the suggested echo mechanism combines the features of both spin and phonon echoes.Comment: 13 pages, 3 figure

Deconstructing interventions: approaches to studying behavior change techniques across obesity interventions

Deconstructing interventions into the specific techniques that are used to change behavior represents a new frontier in behavioral intervention research. This paper considers opportunities and challenges in employing the Behavior Change Techniques Taxonomy (BCTTv1) developed by Michie and colleagues, to code the behavior change techniques (BCTs) across multiple interventions addressing obesity and capture dose received at the technique level. Numerous advantages were recognized for using a shared framework for intervention description. Coding interventions at levels of the social ecological framework beyond the individual level, separate coding for behavior change initiation vs. maintenance, fidelity of BCT delivery, accounting for BCTs mode of delivery, and tailoring BCTs, present both challenges and opportunities. Deconstructing interventions and identifying the dose required to positively impact health-related outcomes could enable important gains in intervention science