Engineering current density over 5 kA mm-2 at 4.2 K, 14 T in thick film REBCO tapes

We report on remarkably high in-field performance at 4.2 K achieved in >4 μm thick rare earth barium copper oxide (REBCO) samples with Zr addition. Two different samples have been measured independently at Lawrence Berkeley National Laboratory and the National High Magnetic Field Laboratory, achieving critical current densities (J ) of 12.21 MA cm and 12.32 MA cm at 4.2 K, 14 T (), respectively, which corresponds to equivalent critical current (I ) values of 2247 and 2119 A/4 mm. These I values are about two times higher than the best reported performance of REBCO tapes to date and more than five times higher than the commercial HTS tapes reported in a recent study. The measured J values, with a pinning force of ∼1.7 T N m are almost identical to the highest value reported for thin (∼1 μm thick) REBCO at the field and temperature, but extended to very thick (>4 μm) films. This results in an engineering current density (J ) above 5 kA mm at 4.2 K, 14 T, which is more than five times higher than Nb Sn and nearly four times higher than the highest reported value of all superconductors other than REBCO at this field and temperature. The reported results have been achieved by utilizing an advanced metal organic chemical vapor deposition system. This study demonstrates the remarkable level of in-field performance achievable with REBCO conductors at 4.2 K and strong potential for high-field magnet applications. c c c c e 3 -2 -2 -3 -

Rutherford cables with anisotropic transverse resistance

Putting a resistive core into the center of a Rutherford cable increases resistance between strands in the crossover direction, which greatly reduces the coupling currents, even when the resistance to adjacent turns remains small. This allows one to improve stability by soldering strands together or using porous metal, without incurring a penalty of increased coupling. We describe our manufacturing methods and an experimental measurement of coupling

Tripled critical current in racetrack coils made of Bi-2212 Rutherford cables with overpressure processing and leakage control

We fabricated three racetrack coils (RC1, RC2, and RC3) from Bi-2212 Rutherford cables (17-strand, thickness × width = 1.44 mm × 7.8 mm, strand diameter = 0.8 mm) and applied overpressure processing heat treatment (OPHT). The quench currents of RC1 and RC2 reached 5268 A and 5781 A, respectively, despite them still, surprisingly, exhibiting some Bi-2212 leakage to the surface. After removing most of the leakages using a simple-to-implement insulation scheme, the quench current of RC3 improved to 6485 A, which is about three times the average quench current of a dozen racetrack coils that had been fabricated and reacted using the conventional 1 bar heat treatment. The results confirm the effectiveness of the OPHT technology and the new leakage control scheme for coils made from Bi-2212 Rutherford cables. Coils exhibited an increased quench current with increasing the current ramp rate from 5 to 200 A s ; they were quite stable against point and transient disturbances, and were capable of adsorbing persistent Joule heating at ∼80 mW for >15 s before quenching. These behaviors are different from Nb-Ti and Nb Sn accelerator magnets. Overall, our results provide a critical evaluation and verification of Bi-2212 wire and magnet technologies (wire, insulation, heat treatment, coil fabrication, and coil operation), reveal crucial new stability features of Bi-2212 magnets, and demonstrate technological options for it to become a practical high-field magnet technology. -1

Analysis of benthic infauna communities and sedimentation patterns of a proposed fill site and nearby regions in the Columbia River Estuary

The Port of Astoria has proposed to fill a 32.4 hectare inter- and subtidal area at the mouth of Youngs Bay, Columbia River, Oregon. The possible effects of this fill on the biota and sedimentation patterns of this area were studied from 31 August 1975 to 29 February 1976. Part I, the biological studies, analyzed the quantity of benthic life at the fill site in comparison to that in the lower 28 miles of the Columbia River estuary. The sediment textures of benthos samples were analyzed to determine sediment-fauna relations; salinity-temperature measurements were made at selected sites. Fish life at the fill site was also sampled to determine species composition and the relation of fish stomach contents to benthic life. Studies on sedimentation patterns (based on dredging records, photographs, and sediment samples taken in Slip 2 of the port docks) aimed at identifying undesirable sediment deposits which might occur because of the fill. The dominant benthic taxa at most stations were amphipods and polychaetes, although oligochaetes were abundant at some muddy stations. Amphipod densities in the lower river varied from about 200/m2 in deep areas to between 5,000 and 50,000/m2 in shallow, fine sediment areas such as Youngs Bay and extensive shoaling areas. These areas of high density, which include the fill site, were dominated by the tube-building amphipod Corophium. Twenty-five species of fish have been captured in this and previous work in Youngs Bay. Food habit studies have shown Corophium to be eaten in large quantities by many of these species. Using density estimates and river bathymetry as guides, it was very roughly estimated that 0.8 percent of the amphipod standing crop in the study area (CRM 0-28) occurred at the fill site, which represents 0.09 percent of this area. Net sediment transport seems to be from the Columbia River into Youngs Bay, but transport out of Youngs Bay does occur and may contribute greatly to sediment deposition in Slips 1 and 2. Sediment samples from Slip 2 were mud, but this changed abruptly to coarse sand at the slip mouth. This shows that slip sediments arise from suspended fine mud and not from coarser-grained bed-load sediments. There is little that can be done to prevent such deposition. The proposed extension would probably not affect this problem, but might alter the flow of water around the port. More extensive investigations of circulation and suspended sediment content should be made

The rhesus macaque is three times as diverse but more closely equivalent in damaging coding variation as compared to the human

Abstract Background As a model organism in biomedicine, the rhesus macaque (Macaca mulatta) is the most widely used nonhuman primate. Although a draft genome sequence was completed in 2007, there has been no systematic genome-wide comparison of genetic variation of this species to humans. Comparative analysis of functional and nonfunctional diversity in this highly abundant and adaptable non-human primate could inform its use as a model for human biology, and could reveal how variation in population history and size alters patterns and levels of sequence variation in primates. Results We sequenced the mRNA transcriptome and H3K4me3-marked DNA regions in hippocampus from 14 humans and 14 rhesus macaques. Using equivalent methodology and sampling spaces, we identified 462,802 macaque SNPs, most of which were novel and disproportionately located in the functionally important genomic regions we had targeted in the sequencing. At least one SNP was identified in each of 16,797 annotated macaque genes. Accuracy of macaque SNP identification was conservatively estimated to be >90%. Comparative analyses using SNPs equivalently identified in the two species revealed that rhesus macaque has approximately three times higher SNP density and average nucleotide diversity as compared to the human. Based on this level of diversity, the effective population size of the rhesus macaque is approximately 80,000 which contrasts with an effective population size of less than 10,000 for humans. Across five categories of genomic regions, intergenic regions had the highest SNP density and average nucleotide diversity and CDS (coding sequences) the lowest, in both humans and macaques. Although there are more coding SNPs (cSNPs) per individual in macaques than in humans, the ratio of dN/dS is significantly lower in the macaque. Furthermore, the number of damaging nonsynonymous cSNPs (have damaging effects on protein functions from PolyPhen-2 prediction) in the macaque is more closely equivalent to that of the human. Conclusions This large panel of newly identified macaque SNPs enriched for functionally significant regions considerably expands our knowledge of genetic variation in the rhesus macaque. Comparative analysis reveals that this widespread, highly adaptable species is approximately three times as diverse as the human but more closely equivalent in damaging variation.http://deepblue.lib.umich.edu/bitstream/2027.42/112453/1/12863_2011_Article_1004.pd

Monkey-based Research on Human Disease: The Implications of Genetic Differences

Assertions that the use of monkeys to investigate human diseases is valid scientifically are frequently based on a reported 90–93% genetic similarity between the species. Critical analyses of the relevance of monkey studies to human biology, however, indicate that this genetic similarity does not result in sufficient physiological similarity for monkeys to constitute good models for research, and that monkey data do not translate well to progress in clinical practice for humans. Salient examples include the failure of new drugs in clinical trials, the highly different infectivity and pathology of SIV/HIV, and poor extrapolation of research on Alzheimer’s disease, Parkinson’s disease and stroke. The major molecular differences underlying these inter-species phenotypic disparities have been revealed by comparative genomics and molecular biology — there are key differences in all aspects of gene expression and protein function, from chromosome and chromatin structure to post-translational modification. The collective effects of these differences are striking, extensive and widespread, and they show that the superficial similarity between human and monkey genetic sequences is of little benefit for biomedical research. The extrapolation of biomedical data from monkeys to humans is therefore highly unreliable, and the use of monkeys must be considered of questionable value, particularly given the breadth and potential of alternative methods of enquiry that are currently available to scientists

Cholinergic Interneurons Mediate Fast VGluT3-Dependent Glutamatergic Transmission in the Striatum

The neurotransmitter glutamate is released by excitatory projection neurons throughout the brain. However, non-glutamatergic cells, including cholinergic and monoaminergic neurons, express markers that suggest that they are also capable of vesicular glutamate release. Striatal cholinergic interneurons (CINs) express the Type-3 vesicular glutamate transporter (VGluT3), although whether they form functional glutamatergic synapses is unclear. To examine this possibility, we utilized mice expressing Cre-recombinase under control of the endogenous choline acetyltransferase locus and conditionally expressed light-activated Channelrhodopsin2 in CINs. Optical stimulation evoked action potentials in CINs and produced postsynaptic responses in medium spiny neurons that were blocked by glutamate receptor antagonists. CIN-mediated glutamatergic responses exhibited a large contribution of NMDA-type glutamate receptors, distinguishing them from corticostriatal inputs. CIN-mediated glutamatergic responses were insensitive to antagonists of acetylcholine receptors and were not seen in mice lacking VGluT3. Our results indicate that CINs are capable of mediating fast glutamatergic transmission, suggesting a new role for these cells in regulating striatal activity

The ecology of human-caused mortality for a protected large carnivore

Mitigating human-caused mortality for large carnivores is a pressing global challenge for wildlife conservation. However, mortality is almost exclusively studied at local (within-population) scales creating a mismatch between our understanding of risk and the spatial extent most relevant to conservation and management of wide-ranging species. Here, we quantified mortality for 590 radio-collared mountain lions statewide across their distribution in California to identify drivers of human-caused mortality and investigate whether human-caused mortality is additive or compensatory. Human-caused mortality, primarily from conflict management and vehicles, exceeded natural mortality despite mountain lions being protected from hunting. Our data indicate that human-caused mortality is additive to natural mortality as population-level survival decreased as a function of increasing human-caused mortality and natural mortality did not decrease with increased human-caused mortality. Mortality risk increased for mountain lions closer to rural development and decreased in areas with higher proportions of citizens voting to support environmental initiatives. Thus, the presence of human infrastructure and variation in the mindset of humans sharing landscapes with mountain lions appear to be primary drivers of risk. We show that human-caused mortality can reduce population-level survival of large carnivores across large spatial scales, even when they are protected from hunting