3,350 research outputs found

    Expression, Purification, Crystallization and Preliminary X-Ray Analysis of \u3cem\u3ePseudomonas aeuginosa\u3c/em\u3e AlgX

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    AlgX is a periplasmic protein required for the production of the exopolysaccharide alginate in Pseudomonas sp. and Azotobacter vinelandii. AlgX has been overexpressed and purified and diffraction-quality crystals have been grown using iterative seeding and the hanging-drop vapor-diffusion method. The crystals grew as flat plates with unit-cell parameters a=46.4, b=120.6, c=86.9Å, β=95.7°. The cyrstals exhibited the symmetry of space group P21 and diffracted to a minimimum d-spacing of 2.1Å. On the basis of the Matthews coefficient (VM=2.25Å3 Da-1), two molecules were estimated to be present in the asymmetric unit

    Thinking Bigger and Better about "Bad Apples": Evolutionary Industrial/Organizational psychology and the Dark Triad

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    The focal article by Guenole (2014) correctly contends that industrial– organizational (I–O) psychology has been overly reliant on the Big Five or the five-factor model (Benet-Martínez & John, 1998). Although popular and useful, the Big Five also tends to be limited in two important ways. The Big Five is a set of atheoretically derived, descriptive adjectives, and it tends to better tap ‘‘positive’’ aspects of people’s personality over ‘‘negative’’ or ‘‘darker’’ sides. A number of authors have highlighted the importance of examining ‘‘darker’’ aspects of people’s personality both outside (Jonason, Li, Webster, & Schmitt, 2009; Lee & Ashton, 2005; Paulhus & Williams, 2002) and within (Hogan & Hogan, 2001; Jonason, Slomski, & Partyka, 2012) the workplace. As potential mechanisms to explore the ‘‘darker’’ aspects of the workplace, the author of the focal article suggests the Dark Triad of personality (i.e., narcissism, psychopathy, and Machiavellianism). Although the focal article was not solely about these three, we use them as examples to illustrate a broader point: An evolutionary perspective can provide a foundational theory through which workplace phenomenon can be examined with greater richness

    A peroxidase homologue and novel plastocyanin located by proteomics to the Arabidopsis chloroplast thylakoid lumen

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    AbstractA study by two-dimensional electrophoresis showed that the soluble, lumenal fraction of Arabidopsis thaliana thylakoids can be resolved into 300 protein spots. After subtraction of low-intensity spots and accounting for low-level stromal contamination, the number of more abundant, lumenal proteins was estimated to be between 30 and 60. Two of these proteins have been identified: a novel plastocyanin that also was the predominant component of the total plastocyanin pool, and a putative ascorbate peroxidase. Import studies showed that these proteins are routed to the thylakoid lumen by the Sec- and delta pH-dependent translocation pathways, respectively. In addition, novel isoforms of PsbO and PsbQ were identified

    A Web of Expectations: Evolving Relationships in Community Participatory Geoweb Projects.

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    This article was first published in ACME: An International Journal for Critical Geographies in 2015, available online: http://ojs.unbc.ca/index.php/acme/article/view/1235/1030.New forms of participatory online geospatial technology have the potential to support citizen engagement in governance and community development. The mechanisms of this contribution have predominantly been cast in the literature as ‘citizens as sensors’, with individuals acting as a distributed network, feeding academics or government with data. To counter this dominant perspective, we describe our shared experiences with the development of three community-based Geospatial Web 2.0 (Geoweb) projects, where community organizations were engaged as partners, with the general aim to bring about social change in their communities through technology development and implementation. Developing Geoweb tools with community organizations was a process that saw significant evolution of project expectations and relationships. As Geoweb tool development encountered the realities of technological development and implementation in a community context, this served to reduce organizational enthusiasm and support for projects as a whole. We question the power dynamics at play between university researchers and organizations, including project financing, both during development and in the long term. How researchers managed, or perpetuated, many of the popular myths of the Geoweb, namely that it is inexpensive and easy to use (thought not to build, perhaps) impacted the success of each project and the sustainability of relationships between researcher and organization. Ultimately, this research shows the continuing gap between the promise of online geospatial technology, and the realities of its implementation at the community level.Peer-reviewe

    Thalamic medial dorsal nucleus atrophy in medial temporal lobe epilepsy: A VBM meta-analysis

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    Purpose: Medial temporal lobe epilepsy (MTLE) is associated with MTLE network pathology within and beyond the hippocampus. The purpose of this meta-analysis was to identify consistent MTLE structural change to guide subsequent targeted analyses of these areas. Methods: We performed an anatomic likelihood estimation (ALE) meta-analysis of 22 whole-brain voxel-based morphometry experiments from 11 published studies. We grouped these experiments in three ways. We then constructed a meta-analytic connectivity model (MACM) for regions of consistent MTLE structural change as reported by the ALE analysis. Key findings: ALE reported spatially consistent structural change across VBM studies only in the epileptogenic hippocampus and the bilateral thalamus; within the thalamus, the medial dorsal nucleus of the thalamus (MDN thalamus) represented the greatest convergence (Pb0.05 corrected for multiple comparisons). The subsequent MACM for the hippocampus and ipsilateral MDN thalamus demonstrated that the hippocampus and ipsilateral MDN thalamus functionally co-activate and are nodes within the same network, suggesting that MDN thalamic damage could result from MTLE network excitotoxicity. Significance: Notwithstanding our large sample of studies, these findings aremore restrictive thanprevious reports and demonstrate the utility of our inclusion filters and of recently modified meta-analyticmethods in approximating clinical relevance. Thalamic pathology is commonly observed in animal and human studies, suggesting it could be a clinically useful indicator. Thalamus-specific research as a clinical marker awaits further investigation

    Advanced Caution and Warning System

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    The current focus of ACAWS is on the needs of the flight controllers. The onboard crew in low-Earth orbit has some of those same needs. Moreover, for future deep-space missions, the crew will need to accomplish many tasks autonomously due to communication time delays. Although we are focusing on flight controller needs, ACAWS technologies can be reused for on-board application, perhaps with a different level of detail and different display formats or interaction methods. We expect that providing similar tools to the flight controllers and the crew could enable more effective and efficient collaboration as well as heightened situational awareness

    A Geochemical Study of Marine Sediments from the Mac. Robertson Shelf, East Antarctica: Initial Results and Palaeoenvironmental Implications

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    Sediments from the Antarctic continental margin may provide detailed palaeoenvironmental records for Antarctic shelf waters during the late Quaternary. Here we present results from a palaeoenvironmental study of two sediment cores recovered from the continental shelf off Mac. Robertson Land, East Antarctica. These gravity cores were collected approximately 90 km apart from locations on the inner and outer shelf. Both cores are apparently undisturbed sequences of diatom ooze mixed with fine, quartz-rich sand. Core stratigraphies have been established from radiocarbon analyses of bulk organic carbon. Down-core geochemical determinations include the lithogenic components Al and Fe, biogenic components opal and organic carbon, and palaeo-redox proxies Mn, Mo and U. We use the geochemical data to infer past variations in the deposition of biogenic and lithogenic materials, and the radiocarbon dates to estimate average sediment accumulation rates. The Holocene record of the outer-shelf core suggests three episodes of enhanced diatom export production at about 1.8, 3.8 and 5.5 ka BP, as well as less pronounced bloom episodes which occurred over a shorter period. Average sediment accumulation rates at this location range from 13.7 cm ka-1 in the late Pleistocene-early Holocene to 82 cm ka-1 in the late Holocene, and suggest that the inferred episodes of enhanced biogenic production lasted 100- 1000 years. In contrast, data for the inner-shelf core suggest that there has been a roughly constant proportion of biogenic and lithogenic material accumulating during the middle to late Holocene, with a greater proportion of biogenic material relative to the outer shelf. Notably, there is an approximately 7-fold increase in average sediment accumulation rate (from 24.5 to 179 cm ka-1 ) at this inner-shelf location between the middle and late Holocene, with roughly comparable increases in the mass accumulation rates of both biogenic and lithogenic material. This may represent changes in sediment transport processes, or reflect real increases in pelagic sedimentation in this region during the Holocene. Our results suggest quite different sedimentation regimes in these two shelf locations during the middle to late Holocene

    Repetitive Stimulation of the Pituitary with Growth-Hormone-Releasing Hormone Alters the Proportion of 22 and 20 Kilodalton Human-Growth Hormone Released

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    Background/Aims. 20 Kilodalton-hGH (20 K-hGH) is the second most abundant pituitary GH variant after 22 K-hGH. In the steady state the proportion of 20 : 22 K-hGH appears constant; does this proportion change with repetitive somatotroph stimulation? Methods. Forty adult males were randomised to receive a GHRH(1–29)NH2 bolus (0.5 μg/kg (n = 20) or 1.0 μg/kg (n = 20)), preceded or followed by a saline bolus, 1 week apart. Four to six weeks later, 10 subjects received 0.5 μg/kg GHRH(1–29)NH2 at 0, 60, 120, and 180 minutes. Clearance rate of 22 and 20 K-hGH was measured in 10 subjects. Results. Total amount/proportion of 22 K-hGH/20 K-hGH secreted was similar for both GHRH(1–29)NH2 doses. Repetitive stimulation reduced the amount of 22 K-hGH released whereas the amount of 20 K-hGH did not change significantly leading to an increase in the proportion of 20 K-hGH (P = .05). Half-life of 20 and 22 K-hGH were not significantly different (P = .55). Conclusions. Repetitive stimulation of the somatotroph may alter the proportion of GH variant released

    HST Imaging Polarimetry of the Gravitational Lens FSC10214+4724

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    We present imaging polarimetry of the extremely luminous, redshift 2.3 IRAS source FSC10214+4724. The observations were obtained with HST's Faint Object Camera in the F437M filter, which is free of strong emission lines. The 0.7 arcsec long arc is unresolved to 0.04 arcsec FWHM in the transverse direction, and has an integrated polarization of 28 +/- 3 percent, in good agreement with ground-based observations. The polarization position angle varies along the arc by up to 35 deg. The overall position angle is 62 +/- 3 deg east of north. No counterimage is detected to B = 27.5 mag (3σ3\sigma), giving an observed arc to counterimage flux ratio greater than 250, considerably greater than the flux ratio of 100 measured previously in the I-band. This implies that the configuration of the object in the source plane at the B-band is different from that at I-band, and/or that the lensing galaxy is dusty.Comment: 17 pages, 3 figures. Accepted for publication in Astronomical Journal, February 199
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