44 research outputs found
Dynamics of an Unbounded Interface Between Ordered Phases
We investigate the evolution of a single unbounded interface between ordered
phases in two-dimensional Ising ferromagnets that are endowed with
single-spin-flip zero-temperature Glauber dynamics. We examine specifically the
cases where the interface initially has either one or two corners. In both
examples, the interface evolves to a limiting self-similar form. We apply the
continuum time-dependent Ginzburg-Landau equation and a microscopic approach to
calculate the interface shape. For the single corner system, we also discuss a
correspondence between the interface and the Young tableau that represents the
partition of the integers.Comment: 9 pages, 11 figures, 2-column revtex4 format. V2: references added
and discussion section expanded slightly. Final version for PRE. V3: A few
small additional editorial change
Detector Description and Performance for the First Coincidence Observations between LIGO and GEO
For 17 days in August and September 2002, the LIGO and GEO interferometer
gravitational wave detectors were operated in coincidence to produce their
first data for scientific analysis. Although the detectors were still far from
their design sensitivity levels, the data can be used to place better upper
limits on the flux of gravitational waves incident on the earth than previous
direct measurements. This paper describes the instruments and the data in some
detail, as a companion to analysis papers based on the first data.Comment: 41 pages, 9 figures 17 Sept 03: author list amended, minor editorial
change
Cloning of a cDNA encoding bovine erythropoietin and analysis of its transcription in selected tissues
A bobine cDNA encoding erythropoietin (Epo) was isolated by polymerase chain reaction (PCR) amplification and screening of a bovine kidney cDNA library. The sequenced cDNA has a length of 1312 bp and an open reading frame that encodes a predicted 192-amino-acid (aa) protein, including a putative signal sequence of 25 aa. A mature protein of 167 aa (18.4 kDa) results upon cleavage of the putative signal peptide. The deduced bovine mature Epo peptide exhibits 96, 88, 83, 82 and 79 sequence identity to that of sheep, swine, human, monkey and rat, respectively. The expression of the bovine Epo gene in tissues from a severely anemic calf, bovine fetus and a healthy steer was analysed by a competitive RT-PCR method. In kidneys of the severely anemic calf, Epo mRNA levels increased 60-fold relative to that from the kidneys of the healthy steer. Epo mRNA levels were threefold higher in the liver of the bovine fetus than that in its kidneys. Low levels of Epo transcripts were detected in RNA from spleen of the severely anemic calf and the bovine fetus. No Epo transcripts were detectable in spleen from the healthy steer
Analysis of erythropoietin and erythropoietin receptor genes expression in cattle during acute infection with Trypanosoma congolense
Acute Trypanosoma congolense infection induced moderate, transient anemia in N'Dama cattle (trypanotolerant) and severe anemia in Boran cattle (trypanosusceptible). Erythropoietin receptor (EpoR) was cloned and sequenced from the two breeds of cattle. A single position mutation of Tyr in the Boran to His in the N'Dama predicted amino acid sequence was revealed. The mRNA transcription of erythropoietin (Epo) in kidneys and EpoR in the bone marrow of infected cattle was determined by competitive reverse transcription and the polymerase chain reaction (RT-PCR). Through Epo mRNA transcription increased in the kidneys during infection, the increase was not significantly different (p>0.05) between the two breeds of infected cattle. The level of EpoR transcripts in the bone marrow of infected N'Damas was significantly higher p<0.05) than that detected in the marrows from infected Boran cattle. While infection seem to increase levels of transcription of IL-1 alfa and beta, and TNF alfa in kidneys from both Boran and N'Dama cattle, no significant difference was detected in the level of mRNAs of these cytokines in the kidney from the two breed of cattle. The amount of IFN mRNA transcripts were not changed with infection in N'Dama cattle, while on the contrary a significant higher levels of IFN was found in kidneys from infected Boran cattle as compared to the infected N'Dama cattle. In this study the increease in the level of TNF alfa mRNA in the marrows of the two infected breeds was not different. This implies there is no negative effect of TNF alfa on hematopoiesis during acute infection. These findings suggest that the levels of Epo and EpoR in the infected Boran cattle were inadequate for their degree of anemia, which might be due in part to high expression of IFN during acute infection with T. congolense