208 research outputs found
Multifaceted Faculty Network Design and Management: Practice and Experience Report
We report on our experience on multidimensional aspects of our faculty's
network design and management, including some unique aspects such as
campus-wide VLANs and ghosting, security and monitoring, switching and routing,
and others. We outline a historical perspective on certain research, design,
and development decisions and discuss the network topology, its scalability,
and management in detail; the services our network provides, and its evolution.
We overview the security aspects of the management as well as data management
and automation and the use of the data by other members of the IT group in the
faculty.Comment: 19 pages, 11 figures, TOC and index; a short version presented at
C3S2E'11; v6: more proofreading, index, TOC, reference
Purification and characterization of an alcohol dehydrogenase from 1,2-propanediol-grown Desulfovibriostrain HDv
The sulfate-reducing bacterium Desulfovibrio strain HDv (DSM 6830) grew faster on (S)- and on (R, S)-1,2-propanediol (”max 0.053 hâ1) than on (R)-propanediol (0.017 hâ1) and ethanol (0.027 hâ1). From (R, S)-1,2-propanediol-grown cells, an alcohol dehydrogenase was purified. The enzyme was oxygen-labile, NAD-dependent, and decameric; the subunit mol. mass was 48 kDa. The N-terminal amino acid sequence indicated similarity to alcohol dehydrogenases belonging to family III of NAD-dependent alcohol dehydrogenases, the first 21 N-terminal amino acids being identical to those of the Desulfovibrio gigas alcohol dehydrogenase. Best substrates were ethanol and propanol (Km of 0.48 and 0.33 mM, respectively). (R, S)-1,2-Propanediol was a relatively poor substrate for the enzyme, but activities in cell extracts were high enough to account for the growth rate. The enzyme showed a preference for (S)-1,2-propanediol over (R)-1,2-propanediol. Antibodies raised against the alcohol dehydrogenase of D. gigas showed cross-reactivity with the alcohol dehydrogenase of Desulfovibrio strain HDv and with cell extracts of six other ethanol-grown sulfate-reducing bacteria.
Erythrocyte biomarker-based validation of a diet history method used in a dietary intervention trial
Whole-genome sequencing to understand the genetic architecture of common gene expression and biomarker phenotypes.
Initial results from sequencing studies suggest that there are relatively few low-frequency (<5%) variants associated with large effects on common phenotypes. We performed low-pass whole-genome sequencing in 680 individuals from the InCHIANTI study to test two primary hypotheses: (i) that sequencing would detect single low-frequency-large effect variants that explained similar amounts of phenotypic variance as single common variants, and (ii) that some common variant associations could be explained by low-frequency variants. We tested two sets of disease-related common phenotypes for which we had statistical power to detect large numbers of common variant-common phenotype associations-11 132 cis-gene expression traits in 450 individuals and 93 circulating biomarkers in all 680 individuals. From a total of 11 657 229 high-quality variants of which 6 129 221 and 5 528 008 were common and low frequency (<5%), respectively, low frequency-large effect associations comprised 7% of detectable cis-gene expression traits [89 of 1314 cis-eQTLs at P < 1 Ă 10(-06) (false discovery rate âŒ5%)] and one of eight biomarker associations at P < 8 Ă 10(-10). Very few (30 of 1232; 2%) common variant associations were fully explained by low-frequency variants. Our data show that whole-genome sequencing can identify low-frequency variants undetected by genotyping based approaches when sample sizes are sufficiently large to detect substantial numbers of common variant associations, and that common variant associations are rarely explained by single low-frequency variants of large effect
Natural Products Chemistry and Taxonomy of the Marine Cyanobacterium Blennothrix cantharidosmum
A Papua New Guinea field collection of the marine cyanobacterium Blennothrix cantharidosmum was investigated for its cytotoxic constituents. Bioassay-guided isolation defined the cytotoxic components as the known compounds lyngbyastatins 1 and 3. However, six new acyl proline derivatives, tumonoic acids DâI, plus the known tumonoic acid A were also isolated. Their planar structures were defined from NMR and MS data, while their stereostructures followed from a series of chiral chromatographies, degradation sequences, and synthetic approaches. The new compounds were tested in an array of assays, but showed only modest antimalarial and inhibition of quorum sensing activities. Nevertheless, these are the first natural products to be reported from this genus, and this inspired a detailed morphologic and 16S rDNA-based phylogenetic analysis of the producing organism
High Resolution Images of Orbital Motion in the Trapezium Cluster: First Scientific Results from the MMT Deformable Secondary Mirror Adaptive Optics System
We present the first scientific images obtained with a deformable secondary
mirror adaptive optics system. We utilized the 6.5m MMT AO system to produce
high-resolution (FWHM=0.07'') near infrared (1.6 um) images of the young (~1
Myr) Orion Trapezium theta 1 Ori cluster members. A combination of high spatial
resolution and high signal to noise allowed the positions of these stars to be
measured to within ~0.003'' accuracies. Including previous speckle data
(Weigelt et al. 1999), we analyze a six year baseline of high-resolution
observations of this cluster. Over this baseline we are sensitive to relative
proper motions of only ~0.002''/yr (4.2 km/s at 450 pc). At such sensitivities
we detect orbital motion in the very tight theta 1 Ori B2B3 (52 AU separation)
and theta 1 Ori A1A2 (94 AU separation) systems. Such motions are consistent
with those independently observed by Schertl et al. (2003) with speckle
interferometry, giving us confidence that these very small (~0.002''/yr)
orbital motions are real. All five members of the theta 1 Ori B system appear
likely gravitationally bound. The very lowest mass member of the theta 1 Ori B
system (B4) has K' ~11.66 and an estimated mass of ~0.2 Msun. There was very
little motion (4+/-15 km/s) detected of B4 w.r.t B1 or B2, hence B4 is possibly
part of the theta 1 Ori B group. We suspect that if this very low mass member
is physically associated it most likely is in an unstable (non-hierarchical)
orbital position and will soon be ejected from the group. The theta 1 Ori B
system appears to be a good example of a star formation ``mini-cluster'' which
may eject the lowest mass members of the cluster in the near future. This
``ejection'' process could play a major role in the formation of low mass stars
and brown dwarfs.Comment: To appear in the December 10, 2003 issue of the Astrophysical Journal
21 pages, 14 figures (some in color, but print OK in B&W
A systematic review on 'Foveal Crowding' in visually impaired children and perceptual learning as a method to reduce Crowding
Contains fulltext :
102577.pdf (publisher's version ) (Open Access)Background - This systematic review gives an overview of foveal crowding (the inability to recognize objects due to surrounding nearby contours in foveal vision) and possible interventions. Foveal crowding can have a major effect on reading rate and deciphering small pieces of information from busy visual scenes. Three specific groups experience more foveal crowding than adults with normal vision (NV): 1) children with NV, 2) visually impaired (VI ) children and adults and 3) children with cerebral visual impairment (CVI). The extent and magnitude of foveal crowding as well as interventions aimed at reducing crowding were investigated in this review. The twofold goal of this review is : [A] to compare foveal crowding in children with NV, VI children and adults and CVI children and [B] to compare interventions to reduce crowding. Methods - Three electronic databases were used to conduct the literature search: PubMed, PsycINFO (Ovid), and Cochrane. Additional studies were identified by contacting experts. Search terms included visual perception, contour interaction, crowding, crowded, and contour interactions. Results - Children with normal vision show an extent of contour interaction over an area 1.5-3x as large as that seen in adults NV. The magnitude of contour interaction normally ranges between 1-2 lines on an acuity chart and this magnitude is even larger when stimuli are arranged in a circular configuration. Adults with congenital nystagmus (CN) show interaction areas that are 2x larger than those seen adults with NV. The magnitude of the crowding effect is also 2x as large in individuals with CN as in individuals with NV. Finally, children with CVI experience a magnitude of the crowding effect that is 3x the size of that experienced by adults with NV. Conclusions - The methodological heterogeneity, the diversity in paradigms used to measure crowding, made it impossible to conduct a meta-analysis. This is the first systematic review to compare crowding ratios and it shows that charts with 50% interoptotype spacing were most sensitive to capture crowding effects. The groups that showed the largest crowding effects were individuals with CN, VI adults with central scotomas and children with CVI. Perceptual Learning seems to be a promising technique to reduce excessive foveal crowding effects.14 p
Impact of foods enriched with n-3 long-chain polyunsaturated fatty acids on erythrocyte n-3 levels and cardiovascular risk factors
Consumption of fish or fish oils rich in the n-3 long chain PUFA EPA and DHA may improve multiple risk factors for CVD. The objective of this study was to determine whether regular consumption of foods enriched with n-3 long-chain PUFA can improve n-3 long-chain PUFA status (erythrocytes) and cardiovascular health. Overweight volunteers with high levels of triacylglycerols (TG; >1.6 mmol/l) were enrolled in a 6-month dietary intervention trial conducted in Adelaide (n 47) and Perth (n 39), and randomised to consume control foods or n-3-enriched foods to achieve an EPA + DHA intake of 1 g/d. Test foods were substituted for equivalent foods in their regular diet. Erythrocyte fatty acids, plasma TG and other CVD risk factors were monitored at 0, 3 and 6 months. There were no significant differences between groups for blood pressure, arterial compliance, glucose, insulin, lipids, C-reactive protein (CRP) or urinary 11-dehydro-thromboxane B2 (TXB2) over 6 months, even though regular consumption of n-3-enriched foods increased EPA + DHA intake from 0.2 to 1.0 g/d. However, the n-3 long-chain PUFA content of erythrocytes increased by 35 and 53 % at 3 and 6 months, respectively, in subjects consuming the n-3-enriched foods. These increases were positively associated with measures of arterial compliance and negatively associated with serum CRP and urinary 11-dehydro-TXB2 excretion. Sustainable increases in dietary intakes and erythrocyte levels of n-3 long-chain PUFA can be achieved through regular consumption of suitably enriched processed foods. Such increases may be associated with reduced CV risk.Karen J. Murphy, Barbara J. Meyer, Trevor A. Mori, Valerie Burke, Jackie Mansour, Craig S. Patch, Linda C. Tapsell, Manny Noakes, Peter A. Clifton, Anne Barden, Ian B. Puddey, Lawrence J. Beilin and Peter R. C. How
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