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

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

The genome and transcriptome of the enteric parasite Entamoeba invadens, a model for encystation

BACKGROUND: Several eukaryotic parasites form cysts that transmit infection. The process is found in diverse organisms such as Toxoplasma, Giardia, and nematodes. In Entamoeba histolytica this process cannot be induced in vitro, making it difficult to study. In Entamoeba invadens, stage conversion can be induced, but its utility as a model system to study developmental biology has been limited by a lack of genomic resources. We carried out genome and transcriptome sequencing of E. invadens to identify molecular processes involved in stage conversion. RESULTS: We report the sequencing and assembly of the E. invadens genome and use whole transcriptome sequencing to characterize changes in gene expression during encystation and excystation. The E. invadens genome is larger than that of E. histolytica, apparently largely due to expansion of intergenic regions; overall gene number and the machinery for gene regulation are conserved between the species. Over half the genes are regulated during the switch between morphological forms and a key signaling molecule, phospholipase D, appears to regulate encystation. We provide evidence for the occurrence of meiosis during encystation, suggesting that stage conversion may play a key role in recombination between strains. CONCLUSIONS: Our analysis demonstrates that a number of core processes are common to encystation between distantly related parasites, including meiosis, lipid signaling and RNA modification. These data provide a foundation for understanding the developmental cascade in the important human pathogen E. histolytica and highlight conserved processes more widely relevant in enteric pathogens

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

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

Structure of the germline genome of Tetrahymena thermophila and relationship to the massively rearranged somatic genome

The germline genome of the binucleated ciliate Tetrahymena thermophila undergoes programmed chromosome breakage and massive DNA elimination to generate the somatic genome. Here, we present a complete sequence assembly of the germline genome and analyze multiple features of its structure and its relationship to the somatic genome, shedding light on the mechanisms of genome rearrangement as well as the evolutionary history of this remarkable germline/soma differentiation. Our results strengthen the notion that a complex, dynamic, and ongoing interplay between mobile DNA elements and the host genome have shaped Tetrahymena chromosome structure, locally and globally. Non-standard outcomes of rearrangement events, including the generation of short-lived somatic chromosomes and excision of DNA interrupting protein-coding regions, may represent novel forms of developmental gene regulation. We also compare Tetrahymenas germline/soma differentiation to that of other characterized ciliates, illustrating the wide diversity of adaptations that have occurred within this phylum.</p