292 research outputs found
Method of joining metals of significantly different expansion rates
To join a refractory metal to a dissimilar high-temperature metal, braze a section of high elasticity, high ductility metal /such as columbium or columbium alloy/ between the metals to be joined, using a fork-type joint to hold the braze and transition member in place during expansion
Investigating the Environment of Mg II Absorption Line Systems With the Sloan Digital Sky Survey
We study the properties of 1880 Mg II absorption line systems using only the photometric data cataloged by the Sloan Digital Sky Survey. To compensate for the lack of redshift information, we develop several background subtraction techniques to isolate galaxies physically associated with the absorption systems. These methods were tested on a set of mock catalogs to ensure that they yield correct results when applied to a set of data.
Upon measuring the absolute magnitude distribution and luminosity function of neighbours of these absorbers, we find a distribution whose shape matches a fiducial model based on a luminosity function at a similar redshift. On scales 0.02 − 0.5 Mpc/h, we find that strong systems have more neighbours than weak ones; when the scale is increased to 0.02 − 1 Mpc/h, weak systems have more neighbours.
Our measured Mg II absorber—neighbouring galaxy projected cross-correlation function demonstrates evidence of a break at ∼ 100 kpc/h (comoving), but is consistent with a single power law over the range 40 kpc/h ≤ rp ≤ 880 kpc/h. The cross-correlation functions of the weak and strong subsamples have similar slopes, but the amplitude of the weak one is higher than that of the strong one.
We use the galaxies closest in angular separation to absorbers to constrain the properties of candidate hosts. The mean absorber–galaxy centre separation is ∼ 30 kpc/h; we also find that strong systems lie closer to the centre of their host galaxies than weak systems
Convolution and deconvolution based estimates of galaxy scaling relations from photometric redshift surveys
In addition to the maximum likelihood approach, there are two other methods
which are commonly used to reconstruct the true redshift distribution from
photometric redshift datasets: one uses a deconvolution method, and the other a
convolution. We show how these two techniques are related, and how this
relationship can be extended to include the study of galaxy scaling relations
in photometric datasets. We then show what additional information photometric
redshift algorithms must output so that they too can be used to study galaxy
scaling relations, rather than just redshift distributions. We also argue that
the convolution based approach may permit a more efficient selection of the
objects for which calibration spectra are required.Comment: 7 pages, 4 figures, accepted for publication in MNRAS; v2 includes a
new section and other minor change
Plasma Membrane Repair Is Mediated by Ca2+-Regulated Exocytosis of Lysosomes
AbstractPlasma membrane wounds are repaired by a mechanism involving Ca2+-regulated exocytosis. Elevation in intracellular [Ca2+] triggers fusion of lysosomes with the plasma membrane, a process regulated by the lysosomal synaptotagmin isoform Syt VII. Here, we show that Ca2+-regulated exocytosis of lysosomes is required for the repair of plasma membrane disruptions. Lysosomal exocytosis and membrane resealing are inhibited by the recombinant Syt VII C2A domain or anti-Syt VII C2A antibodies, or by antibodies against the cytosolic domain of Lamp-1, which specifically aggregate lysosomes. We further demonstrate that lysosomal exocytosis mediates the resealing of primary skin fibroblasts wounded during the contraction of collagen matrices. These findings reveal a fundamental, novel role for lysosomes: as Ca2+-regulated exocytic compartments responsible for plasma membrane repair
Technology and Opportunity: People with Serious Mental Illness and Social Connection
Objective: Little information exists regarding how individuals with serious mental illness use technology and whether this usage facilitates social connections. This study contributes to filling this knowledge gap by examining ways in which a sample of persons with serious mental illness use cell phones and the Internet. Methods: Interviews with 50 consumers living in supported housing were asked about their use of cell phones and computers and their perceptions of social connections. Results: Cell phones and computers allowed greater linkage with social, medical, mental health, and employment resources. Nearly all obtained phones through publicly funded programs. “Running out of minutes” was common and associated with disrupted communication and safety concerns. Few people owned computers, resulting in restricted access. Conclusion: Policymakers should consider providing free or discounted hardware, subsidizing unlimited plans, and promoting computer literacy
Expert Assertions Through Community Annotation Jamborees
Although there is significant optimism that community involvement can drive genome curation, results to date are disappointing. The Human Genome and Saccharomyces Genome Databases both tried community annotation experiments and few community contributions were obtained. JCVI’s own early experiences with community curation were also largely unsuccessful. Although community curation tools were publicly available on JCVI web resources and much effort was made by JCVI personnel to advertise these resources, little curation was actually submitted. Starting in late 2007, JCVI’s model for community curation changed. Instead of simply providing curation tools on websites and advertising their utility at meetings and conferences, JCVI instituted a community curation jamboree model. 

Annotation jamborees are an excellent form of outreach to the community. JCVI’s experience conducting jamborees is highly successful, demonstrating that jamborees are effective tools for incorporating expert annotation data into existing genome submissions, updating existing annotation, tagging annotation with updated experimental references and providing the community with opportunities to become familiar with JCVI’s annotation procedures and curation tools. Jamborees provide a means to directly interact with the community and integrate their research expertise into genomic data sets. Jamboree participants are encouraged to provide their expert input by focusing on their genes and gene families of interest, particularly those with supporting experimental evidence. Through JCVI’s NIAID Bioinformatics Resource Center, Pathema ("http://pathema.jcvi.org":http://pathema.jcvi.org), JCVI hosted two annotation jamborees incorporating expert annotation into Entamoeba and Burkholderia genome projects. These jamborees resulted in curation of 1,565 functional assignments, 3,499 Gene Ontology terms, 129 gene structures, and 296 experimental references for 11 genome projects representative of the Pathema data set. Researchers who contributed to annotation at these jamborees are being submitted as contributing authors on annotation update submissions made to GenBank for those organisms. Additionally, the annotation associated with the submission is recognized as part of community curation efforts and collaboration, and all updates and contributions are reflected on the Pathema web resource.

The networking and personal communication that occurs throughout a jamboree facilitates a forum for research and data exchange, solicitation of user feedback and the establishment of new community collaborations. Although integrating and updating annotation data is important, it is our experience that the interactions that occur and collaborations that are formed are the most beneficial long-term results of jamboree efforts. Collaborations we established as a direct result of jamboree activity include continued community annotation, custom data analyses and general informatics support not otherwise solicited by the researcher. For the jamborees JCVI recently hosted, we established successful collaborations with four researchers who continued to provide curation from their own institute
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