Characterizations of electrical properties of highT(sub c) superconducting materials

The automated data acquisition system developed in the Space Science Laboratory at Marshall Space Flight Center for measuring electrical properties of high temperature superconductors is described. The acquisition system, consisting of a computer and computer-controlled hardware, allows large numbers of voltage, current, temperature, and magnetic measurements to be performed on bulk and thin film samples. Typical results are shown characterizing transition temperature (T sub c), critical current density (J sub c), and magnetic properties of bulk high T(sub c) materials as a function of temperature

Planar thin film SQUID with integral flux concentrator

A thin film SQUID is disclosed having improved flux concentration combined with simplicity of design and fabrication. The SQUID starts with a wafer like substrate having simple planar geometry. A large area of superconducting film is coated on the substrate, with a small open or uncoated area remaining at its center to define a SQUID loop, and a gap in the film formed, beginning at the outer circumferential edge of the substrate and extending radially inward to the open area. A Josephson junction is formed across the gap near the open area to interrupt the electrical continuity of the SQUID loop. A coil is attached to the surface of the substrate, electrically insulated from the superconducting film, and is energized to induce flux within the SQUID which is concentrated within the open area

Redefining Gonadotropin-Releasing Hormone (GnRH) Cell Groups in the Male Syrian Hamster: Testosterone Regulates GnRH mRNA in the Tenia Tecta

Gonadotropin-releasing hormone (GnRH) regulates the production of testosterone via the hypothalamic-pituitary-gonadal axis and testosterone, in turn, regulates the GnRH system via negative feedback. We compared testosterone regulation of GnRH mRNA expression in four anatomically defined GnRH cell groups in juvenile and adult male Syrian hamsters, including a rostral population of GnRH cells in the tenia tecta. In situ hybridization histochemistry (ISHH) was used to measure GnRH mRNA in brains from castrated juveniles and adults treated with 0 mg or 2.5 mg testosterone pellets for one week. ISHH was performed on coronal sections using a 35 S-cRNA probe generated from Syrian hamster GnRH cDNA. Testosterone treatment resulted in a significant reduction in mean area of GnRH neurones covered by silver grains within the tenia tecta, but only a trend toward decreased GnRH mRNA in the diagonal band of Broca/organum vasculosum of the lamina terminalis (DBB/OVLT), medial septum (MS), and caudal preoptic area (cPOA). The effects of testosterone were independent of age. Frequency distribution analyses unveiled a significant reduction in the number of heavily labelled cells following testosterone treatment within the tenia tecta and MS. Simple regression analyses revealed a significant positive correlation between plasma luteinizing hormone concentrations and GnRH mRNA only in the tenia tecta. These data indicate that, overall, GnRH mRNA is modestly reduced by testosterone, and the most robust attenuation of GnRH mRNA occurs within the tenia tecta. This is the first report to link mechanisms of steroid negative feedback with tenia tecta GnRH neurones, providing a new focus for investigating brain region-specific steroidal regulation of GnRH synthesis.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/75357/1/j.0007-1331.2002.00787.x.pd

Processing of strong flux trapping high T(subc) oxide superconductors: Center director's discretionary fund

Magnetic suspension effect was first observed in samples of YBa2Cu3O7/AgO(Y-123/AgO) composites. Magnetization measurements of these samples show a much larger hysteresis which corresponds to a large critical current density. In addition to the Y-123AgO composites, recently similar suspension effects in other RE-123/AgO, where RE stands for rare-Earth elements, were also observed. Some samples exhibit even stronger flux pinning than that of the Y-123/AgO sample. An interesting observation was that in order to form the composite which exhibits strong flux trapping effect the sintering temperature depends on the particular RE-123 compound used. The paper presents the detailed processing conditions for the formation of these RE-123/AgO composites, as well as the magnetization and critical field data

Measurements of the optical properties of thin films of silver and silver oxide

The optical properties of silver films and their oxides are measured to better characterize such films for use as sensors for atomic oxygen. Good agreement between properties of measured pure silver films and reported optical constants is observed. Similar comparisons for silver oxide have not been possible because of a lack of reported constants, but self-consistencies and discrepancies in our measured results are described

Advice to clinicians on communication from adolescents and young adults with cancer and parents of children with cancer

Effective communication is integral to patient and family-centered care in pediatric and adolescent and young adult (AYA) oncology and improving healthcare delivery and outcomes. There is limited knowledge about whether AYAs and parents have similar communication preferences and needs. By eliciting and comparing communication advice from AYAs and parents, we can identify salient guidance for how clinicians can better communicate. We performed secondary analysis of semi-structured interviews from 2 qualitative communication studies. In one study, 80 parents of children with cancer during treatment, survivorship, or bereavement were interviewed. In the second study, AYAs with cancer during treatment or survivorship were interviewed. We asked AYAs and parents to provide communication advice for oncology clinicians. Using thematic analysis, we identified categories of advice related to three overarching themes: interpersonal relationships, informational preferences, and delivery of treatment, resources, and medical care. AYAs and parents provided similar advice about the need for compassion, strong connections, hopefulness, commitment, and transparent honesty However, AYAs placed additional emphasis on clinicians maintaining a calm demeanor

New constraints on light axion-like particles using Chandra transmission grating spectroscopy of the powerful cluster-hosted quasar H1821+643

Axion-like particles (ALPs) are predicted by several Beyond the Standard Model theories, in particular, string theory. In the presence of an external magnetic field perpendicular to the direction of propagation, ALPs can couple to photons. Therefore, if an X-ray source is viewed through a magnetized plasma, such as a luminous quasar in a galaxy cluster, we may expect spectral distortions that are well described by photon–ALP oscillations. We present a 571 ks combined high- and low-energy transmission grating Chandra observation of the powerful radio-quiet quasar H1821+643, hosted by a cool-core cluster at redshift 0.3. The spectrum is well described by a double power-law continuum and broad+narrow iron line emission typical of type-1 active galactic nuclei (AGNs), with remaining spectral features 6.3 × 10−13 GeV−1 for most ALP masses <10−12 eV. Our results are moderately more sensitive to constraining ALPs than the best previous result from Chandra observations of the Perseus cluster, albeit with a less constrained field model. We reflect on the promising future of ALP studies with bright AGNs embedded in rich clusters, especially with the upcoming Athena mission

Evo-devo of human adolescence: beyond disease models of early puberty

Despite substantial heritability in pubertal development, much variation remains to be explained, leaving room for the influence of environmental factors to adjust its phenotypic trajectory in the service of fitness goals. Utilizing evolutionary development biology (evo-devo), we examine adolescence as an evolutionary life-history stage in its developmental context. We show that the transition from the preceding stage of juvenility entails adaptive plasticity in response to energy resources, other environmental cues, social needs of adolescence and maturation toward youth and adulthood. Using the evolutionary theory of socialization, we show that familial psychosocial stress fosters a fast life history and reproductive strategy rather than early maturation being just a risk factor for aggression and delinquency. Here we explore implications of an evolutionary-developmental-endocrinological-anthropological framework for theory building, while illuminating new directions for research

Seeing like the international community: how peacebuilding failed (and survived) in Tajikistan

Post-print version. 18 month embargo by the publisher. Article will be released April 2010.The international community claims transformative power over post-conflict spaces via the concept of peacebuilding. International actors discursively make space for themselves in settings such as the Central Asian state of Tajikistan which endured a civil war during the 1990s and has only seen an end to widespread political violence in recent years. With the work of James C. Scott, this paper challenges the notion that post-conflict spaces are merely the objects of international intervention. It reveals how, even in cases of apparent stability such as that of Tajikistan, international actors fail to achieve their ostensible goals for that place yet make space for themselves in that place. International peacebuilders may provide essential resources for the re-emergence of local forms of order yet these symbolic and material resources are inevitably re-interpreted and re-appropriated by local actors to serve purposes which may be the opposite of their aims. However, despite this ‘failure’ of peacebuilding it nevertheless survives as a discursive construction through highly subjective processes of monitoring and evaluation. So maintained, peacebuilding is a constitutive element of world order where the necessity of intervention for humanitarian, democratic and statebuilding ends goes unchallenged. This raises the question of what or where – in spatial terms – is the locus of international intervention: the local recipients of peacebuilding programmes (who are the ostensible targets) or ‘the International Community’ itself (whose space is re-inscribed as that of an imperfect but necessary regulator of world order)