1,258 research outputs found
Holography of a Composite Inflaton
We study the time evolution of a brane construction that is holographically
dual to a strongly coupled gauge theory that dynamically breaks a global
symmetry through the generation of an effective composite Higgs vev. The D3/D7
system with a background magnetic field or non-trivial gauge coupling (dilaton)
profile displays the symmetry breaking. We study motion of the D7 brane in the
background of the D3 branes. For small field inflation in the field theory the
effective Higgs vev rolls from zero to the true vacuum value. We study what
phenomenological dilaton profile generates the slow rolling needed, hence
learning how the strongly coupled gauge theory's coupling must run. We note
that evolution of our configuration in the holographic direction, representing
the phyiscs of the strong interactions, can provide additional slowing of the
roll time. Inflation seems to be favoured if the coupling changes by only a
small amount or very gently. We speculate on how such a scenario could be
realized away from N=4 gauge theory, for example, in a walking gauge theory.Comment: 13 pages, 12 figures; v2: Added reference
An improved competitive inhibition enzymatic immunoassay method for tetrodotoxin quantification
Quantifying tetrodotoxin (TTX) has been a challenge in both ecological and medical research due to the cost, time and training required of most quantification techniques. Here we present a modified Competitive Inhibition Enzymatic Immunoassay for the quantification of TTX, and to aid researchers in the optimization of this technique for widespread use with a high degree of accuracy and repeatability
Beverage patterns and trends among school-aged children in the US, 1989-2008
<p>Abstract</p> <p>Background</p> <p>High intake of sugar-sweetened beverages in childhood is linked to increased risk of obesity and type II diabetes later in life. Using three nationally representative surveys of dietary intake, we investigated beverage patterns and trends among US school-aged children from 1989/91 to 2007/08.</p> <p>Methods</p> <p>3, 583 participants ages 6-11 y old were included. We reported per capita trends in beverage consumption, percent consuming, and amount per consumer for the following categories of beverages: sugar-sweetened beverages (SSB), caloric nutritional beverages (CNB) and low calorie beverages (LCB). Statistically significant differences were tested using the Student's t test in Stata 11.</p> <p>Results</p> <p>While per capita kcal contribution from total beverages remained constant over the study period, per capita consumption of SSBs increased and CNBs decreased in similar magnitude. The substantial increase in consumption of certain SSBs, such as fruit drinks and soda, high fat high sugar milk, and sports drinks, coupled with the decrease in consumption of high fat low sugar milk was responsible for this shift. The percent consuming SSBs as well as the amount per consumer increased significantly over time. Per capita intake of total milk declined, but the caloric contribution from high fat high sugar milk increased substantially. Among ethnicities, important differences in consumption trends of certain SSBs and 100% juice indicate the complexity in determining strategies for children's beverage calorie reduction.</p> <p>Conclusions</p> <p>As upward trends of SSB consumption parallel increases in childhood obesity, educational and policy interventions should be considered.</p
Accumulating Variation at Conserved Sites in Potyvirus Genomes Is Driven by Species Discovery and Affects Degenerate Primer Design
Unknown and foreign viruses can be detected using degenerate primers targeted at conserved sites in the known viral gene sequences. Conserved sites are found by comparing sequences and so the usefulness of a set of primers depends crucially on how well the known sequences represent the target group including unknown sequences. Methodology/Principal Findings: We developed a method for assessing the apparent stability of consensus sequences at sites over time using deposition dates from Genbank. We tested the method using 17 conserved sites in potyvirus genomes. The accumulation of knowledge of sequence variants over 20 years caused ‘consensus decay ’ of the sites. Rates of decay were rapid at all sites but varied widely and as a result, the ranking of the most conserved sites changed. The discovery and reporting of sequences from previously unknown and distinct species, rather than from strains of known species, dominated the decay, indicating it was largely a sampling effect related to the progressive discovery of species, and recent virus mutation was probably only a minor contributing factor. Conclusion/Significance: We showed that in the past, the sampling bias has misled the choice of the most conserved target sites for genus specific degenerate primers. The history of sequence discoveries indicates primer designs should be update
Predictors of positive blood culture and deaths among neonates with suspected neonatal sepsis in a tertiary hospital, Mwanza- Tanzania
Neonatal sepsis is a significant cause of morbidity and mortality in neonates. Appropriate clinical diagnosis and empirical treatment in a given setting is crucial as pathogens of bacterial sepsis and antibiotic sensitivity pattern can considerably vary in different settings. This study was conducted at Bugando Medical Centre (BMC), Tanzania to determine the prevalence of neonatal sepsis, predictors of positive blood culture, deaths and antimicrobial susceptibility, thus providing essential information to formulate a policy for management of neonatal sepsis. This was a prospective cross sectional study involving 300 neonates admitted at BMC neonatal unit between March and November 2009. Standard data collection form was used to collect all demographic data and clinical characteristics of neonates. Blood culture was done on Brain Heart Infusion broth followed by identification of isolates using conventional methods and testing for their susceptibility to antimicrobial agents using the disc diffusion method. Among 770 neonates admitted during the study period; 300 (38.9%) neonates were diagnosed to have neonatal sepsis by WHO criteria. Of 300 neonates with clinical neonatal sepsis 121(40%) and 179(60%) had early and late onset sepsis respectively. Positive blood culture was found in 57 (47.1%) and 92 (51.4%) among neonates with early and late onset neonatal sepsis respectively (p = 0.466). Predictors of positive blood culture in both early and late onset neonatal sepsis were inability to feed, lethargy, cyanosis, meconium stained liquor, premature rupture of the membrane and convulsion. About 49% of gram negatives isolates were resistant to third generation cephalosporins and 28% of Staphylococcus aureus were found to be Methicillin resistant Staphylococcus aureus (MRSA). Deaths occurred in 57 (19%) of neonates. Factors that predicted deaths were positive blood culture (p = 0.0001), gram negative sepsis (p = 0.0001) and infection with ESBL (p = 0.008) or MRSA (p = 0.008) isolates. Our findings suggest that lethargy, convulsion, inability to feed, cyanosis, PROM and meconium stained liquor are significantly associated with positive blood culture in both early and late onset disease. Mortality and morbidity on neonatal sepsis is high at our setting and is significantly contributed by positive blood culture with multi-resistant gram negative bacteria
Can Communicating Personalised Disease Risk Promote Healthy Behaviour Change? A Systematic Review of Systematic Reviews.
: The assessment and communication of disease risk that is personalised to the individual is widespread in healthcare contexts. Despite several systematic reviews of RCTs, it is unclear under what circumstances that personalised risk estimates promotes change in four key health-related behaviours: smoking, physical activity, diet and alcohol consumption.
: The present research aims to systematically identify, evaluate and synthesise the findings of existing systematic reviews.
: This systematic review of systematic reviews followed published guidance. A search of four databases and two-stage screening procedure with good reliability identified nine eligible systematic reviews.
: The nine reviews each included between three and 15 primary studies, containing 36 unique studies. Methods of personalising risk feedback included imaging/visual feedback, genetic testing, and numerical estimation from risk algorithms. The reviews were generally high quality. For a broad range of methods of estimating and communicating risk, the reviews found no evidence that risk information had strong or consistent effects on health-related behaviours. The most promising effects came from interventions using visual or imaging techniques and with smoking cessation and dietary behaviour as outcomes, but with inconsistent results. Few interventions explicitly used theory, few targeted self-efficacy or response efficacy, and a limited range of Behaviour Change Techniques were used.
: Presenting risk information on its own, even when highly personalised, does not produce strong effects on health-related behaviours or changes which are sustained. Future research in this area should build on the existing knowledge base about increasing the effects of risk communication on behaviour.The present research was funded partly by Research Capability Funding from NIHR CLAHRC Greater Manchester and the charity Prevent Breast Cancer
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