3,500 research outputs found
Towards conformationally-locked difluorosugar analogues : an unexpected sense of dihydroxylation
Difluorinated cyclooctenones, synthesised using RCM, can be used as templates for stereoselective oxidative transformations to products that undergo transannular reactions to afford conformationally-locked analogues of 2-deoxy-2,2-difluorosugars with different stereochemical relationships between the C-2 and C-3 hydroxyl groups
Dimensions of oral health related quality of life measured by EQ-5D+ and OHIP-14
BACKGROUND: The aims of the study were to compare the dimensions of oral-health-related quality-of-life measured by a generic health state measure, the EuroQol, and a specific oral health measure, the Oral Health Impact Profile. METHODS: Data were collected in 2001–02 from a random sample of South Australian dentists using mailed self-complete questionnaires. Dentists recorded the diagnosis of dental problems and provided patients with self-complete questionnaires to record the nature, severity and duration of symptoms using the EuroQol (EQ-5D+) and 14-item version of the Oral Health Impact Profile (OHIP-14) instruments. RESULTS: Data were available from 375 patients (response rate = 72%). The EuroQol items of mobility, self care and usual activities formed a separate cluster of variables, as did anxiety/depression and cognition, while pain clustered with items from the OHIP physical pain subscale. OHIP items tended to form clusters consistent with the subscales of social disability, physical disability, physical pain, functional limitation and psychological discomfort. The OHIP handicap items clustered between the OHIP social disability and physical disability subscales. The OHIP psychological disability items split between the social disability and psychological discomfort subscales. CONCLUSIONS: The observed clusters of variables empirically supported most of the conceptual dimensions of the OHIP. Both instruments covered symptom experience of pain indicating overlapping domains. However there was partial separation of the generic and specific items, EuroQol covered daily activities such as self-care and usual activities and OHIP covered oral health-specific aspects of functional limitation and physical disability as well as psychological and social aspects of disability and handicap
Virus-Host Co-evolution: Determining the Origin of Human Cytomegalovirus US27 and US28
G protein-coupled receptors (GPCR) are the largest family of cell surface proteins, found in organisms from yeast to humans. Human cytomegalovirus (HCMV) is a widespread pathogen that is particularly skilled at evading immune detection and defense mechanisms, largely due to extensive co-evolution with its host’s immune system. One aspect of this co-evolution involves the acquisition of four virally encoded GPCR homologs: US27, US28, UL33 and UL78. In this research, phylogenetic analysis was used to investigate the origins of the US27 and US28 genes, which are adjacent in the viral genome. The results indicate that both US27 and US28 share the same common ancestor, human chemokine receptor CX3CR1, suggesting that a single human gene was captured and a viral gene duplication event occurred. While the evolutionary purpose of the gene duplication event remains unclear, experimental evidence indicates that each gene has evolved distinct, important functions during virus infection
Among-site variability in the stochastic dynamics of East African coral reefs
Coral reefs are dynamic systems whose composition is highly influenced by
unpredictable biotic and abiotic factors. Understanding the spatial scale at
which long-term predictions of reef composition can be made will be crucial for
guiding conservation efforts. Using a 22-year time series of benthic
composition data from 20 reefs on the Kenyan and Tanzanian coast, we studied
the long-term behaviour of Bayesian vector autoregressive state-space models
for reef dynamics, incorporating among-site variability. We estimate that if
there were no among-site variability, the total long-term variability would be
approximately one third of its current value. Thus among-site variability
contributes more to long-term variability in reef composition than does
temporal variability. Individual sites are more predictable than previously
thought, and predictions based on current snapshots are informative about
long-term properties. Our approach allowed us to identify a subset of possible
climate refugia sites with high conservation value, where the long-term
probability of coral cover <= 0.1 was very low. Analytical results show that
this probability is most strongly influenced by among-site variability and by
interactions among benthic components within sites. These findings suggest that
conservation initiatives might be successful at the site scale as well as the
regional scale.Comment: 97 pages, 49 figure
Periodontal Disease in Five and Six Year Old Children
Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/141478/1/jper0019.pd
Are Lengthy and Boilerplate Risk Factor Disclosures Inadequate? An Examination of Judicial and Regulatory Assessments of Risk Factor Language
Prior research finds that lengthy and boilerplate risk factor disclosures are associated with negative capital market consequences. Yet regulators and users of financial statements continue to criticize corporate risk factor disclosures as excessively long and boilerplate. We investigate two potential sources of firms’ incentives to issue lengthy, boilerplate risk factor disclosures by examining how judicial and regulatory assessments of firms’ risk factor disclosures correlate with measures of disclosure length and disclosure boilerplate. Our results suggest that lengthy and more boilerplate risk factor disclosures are less likely to be considered inadequate under judicial and regulatory review. Specifically, risk factor disclosures that are lengthier and less specific are less likely to be flagged as inadequate for safe harbor purposes under the Private Securities Litigation Reform Act. In addition, more standardized risk factor disclosures are less likely to be targeted by an SEC comment letter during the SEC’s filing review process
New Horizons: Long-Range Kuiper Belt Targets Observed by the Hubble Space Telescope
We report on Hubble Space Telescope (HST) observations of three Kuiper Belt
Objects (KBOs), discovered in our dedicated ground-based search campaign, that
are candidates for long-range observations from the New Horizons spacecraft:
2011 JY31, 2011 HZ102, and 2013 LU35. Astrometry with HST enables both current
and future critical accuracy improvements for orbit precision, required for
possible New Horizons observations, beyond what can be obtained from the
ground. Photometric colors of all three objects are red, typical of the Cold
Classical dynamical population within which they reside; they are also the
faintest KBOs to have had their colors measured. None are observed to be binary
with HST above separations of ~0.02 arcsec (~700 km at 44 AU) and {\Delta}m
less than or equal to 0.5.Comment: Pages: 11, Figures: 2, Tables: 3, Icarus, available online May 2014
(http://dx.doi.org/10.1016/j.icarus.2014.04.014
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