Hjemmet

For piano. Badly torn. Cover signed in the upper right hand corner by Ingeborg Rusten (Birgit\u27s stepmother) and Birgit Krohn.https://scholarexchange.furman.edu/krohn-album3/1005/thumbnail.jp

THE BATTLE OF THE SEXES IN SCIENCE FICTION: FROM THE PULPS TO THE JAMES TIPTREE, JR. MEMORIAL AWARD

In this thesis I argue that science fiction is not a genre exclusively made up of written texts but a community or series of communities. I examine the science fiction community's engagement with questions of femeninity, masculinity, sex and sexuality over the past seventy years, that is from 1926 until 1996. My examination of this engagement is centred on the battle of the sexes, the lives of James Tiptree, Jr. and the Award named in Tiptree's honour. I make connections between contemporary feminist science fiction and the earliest pulp science fiction engagements with sex and sexuality

Effect of Carbon-Doping in Bulk Superconducting MgB2 Samples

Bulk superconducting samples of MgB2 were prepared by solid state reaction of stoichiometric quantities of Mg turnings and B in a sealed Ta cylinder at 890 C for 2 hours. The as-synthesized MgB2 samples had a Tc of 39 K, as defined as the onset of diamagnetism. The crystal symmetry was found to be hexagonal with lattice parameters, a=3.0856 A, and c=3.5199 A, similar to the literature values. To study the effect of carbon doping in MgB2, various C-containing samples of x varying from 0 to 1.00 in MgB2-xCx were prepared. Magnetic characterizations indicate that the Tc onset is same for pure and C-doped samples for x = 0.05, and 0.10. However, the shielding signal decreased monotonically with C content, apparently due to the presence of carbon on the grain boundaries that isolates grains and prevents flow of supercurrents on the perimeter.Comment: 10 pages, 3 figure

Significant enhancement of irreversibility field in clean-limit bulk MgB2

Low resistivity ("clean") MgB2 bulk samples annealed in Mg vapor show an increase in upper critical field Hc2(T) and irreversibility field Hirr(T) by a factor of 2 in both transport and magnetic measurements. The best sample displayed Hirr above 14 T at 4.2 K and 6 T at 20 K. These changes were accompanied by an increase of the 40 K resistivity from 1.0 to 18 microohm-cm and a lowering of the resistivity ratio from 15 to 3, while the critical temperature Tc decreased by only 1-2 K. These results point the way to make prepare MgB2 attractive for magnet applications.Comment: 3 pages, 4 figures, submitted to Applied Physics Letter

Characterisation of Parkinson’s Disease risk gene, GTP Cyclohydrolase I, in zebrafish

GTP Cyclohydrolase I (GCH1) is a known Parkinson’s Disease (PD) risk gene, identified in sporadic and familial PD cases. Additionally, mutations in GCH1 are a causative factor for the childhood-onset disorder dopa-responsive dystonia (DRD). GCH1 catalyses the rate-limiting step in the synthesis of tetrahydrobiopterin (BH4), which is an essential cofactor for the synthesis of dopamine and other catecholaminergic neurotransmitters. We hypothesised that GCH1 deficiency may lead to dopaminergic cell degeneration, and thus development of PD, as a direct result of metabolic dopamine deficiency. We generated a gch1 mutant zebrafish line (gch1-/-) to investigate this hypothesis, and to explore additional pathomechanisms by which GCH1 deficiency may contribute to PD risk. gch1-/- zebrafish develop neurotransmitter deficits by 5 dpf, a hypoactive motor phenotype by 8 dpf, and mortality by 12 dpf. Despite striking neurotransmitter deficits, dopaminergic neurons show no evidence of degeneration, however, protein levels of the dopamine-producing enzyme, tyrosine hydroxylase, are depleted. Gene expression analysis from larval brains revealed metabolic dysregulation, induction of matrix metalloproteinases, and inflammatory activation in gch1-/-. Morphological analysis and functional activity assays of microglial activation identified a heightened activation state of microglia in gch1-/-, indicative of a neuroinflammatory phenotype. we reject our hypothesis that dopamine deficiency directly predisposes to degeneration, as despite severe biochemical deficits we do not observe a reduction in the number of dopaminergic neurons in Gch1-deficient zebrafish; however, this project identifies 2 mechanisms – tyrosine hydroxylase (TH) depletion, and neuroinflammation - in Gch1-deficient larvae, which both represent potential pathological mechanisms which may lead to neurodegeneration. We propose that in cases of GCH1-deficiency, PD symptoms appear at an early subclinical stage of nigral degeneration as a result of dopamine deficiency, and this is exacerbated by depletion of TH protein

Development of high critical current density in multifilamentary round-wire Bi2Sr2CaCu2O8+x by strong overdoping

Bi2Sr2CaCu2O8+x is the only cuprate superconductor that can be made into a round-wire conductor form with a high enough critical current density Jc for applications. Here we show that the Jc(5 T,4.2 K) of such Ag-sheathed filamentary wires can be doubled to more than 1.4x10^5 A/cm^2 by low temperature oxygenation. Careful analysis shows that the improved performance is associated with a 12 K reduction in transition temperature Tc to 80 K and a significant enhancement in intergranular connectivity. In spite of the macroscopically untextured nature of the wire, overdoping is highly effective in producing high Jc values.Comment: 4 figure