786 research outputs found
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Large-effect flowering time mutations reveal conditionally adaptive paths through fitness landscapes in Arabidopsis thaliana.
Contrary to previous assumptions that most mutations are deleterious, there is increasing evidence for persistence of large-effect mutations in natural populations. A possible explanation for these observations is that mutant phenotypes and fitness may depend upon the specific environmental conditions to which a mutant is exposed. Here, we tested this hypothesis by growing large-effect flowering time mutants of Arabidopsis thaliana in multiple field sites and seasons to quantify their fitness effects in realistic natural conditions. By constructing environment-specific fitness landscapes based on flowering time and branching architecture, we observed that a subset of mutations increased fitness, but only in specific environments. These mutations increased fitness via different paths: through shifting flowering time, branching, or both. Branching was under stronger selection, but flowering time was more genetically variable, pointing to the importance of indirect selection on mutations through their pleiotropic effects on multiple phenotypes. Finally, mutations in hub genes with greater connectedness in their regulatory networks had greater effects on both phenotypes and fitness. Together, these findings indicate that large-effect mutations may persist in populations because they influence traits that are adaptive only under specific environmental conditions. Understanding their evolutionary dynamics therefore requires measuring their effects in multiple natural environments
Insights into the mechanism for gold catalysis: behaviour of gold(i) amide complexes in solution
We report the synthesis and activity of new mononuclear and dinuclear gold amide complexes . The dinuclear complexes and were characterised by single crystal X-ray analysis. We also report solution NMR and freezing point depression experiments to rationalise their behaviour in solution and question the de-ligation process invoked in gold catalysis
Morphological features of distribution of branches of the ethmoid arteries on from the shape of the orbit
To study the topography of the lattice of the arteries of the labyrinth and their relationship to the form of the orbit was carried out anthropometric measurements by the method of V. N. Shevkunenko, A. M. Eselevich, T. V. Zolotareva, G. N. Toporov. To determine the shape of the orbit was measured by the following parameters: 1 - the height of the entrance to the eye socket - the distance between the upper and lower walls of the orbit; 2 - entrance width - the distance between the inner and outer walls of the orbit; 3 - the depth - the distance between the inner boundary of the entrance into the orbit to the optic canal
Building on the past, shaping the future: The environmental mutagenesis and genomics society
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/97167/1/em21765.pd
Rates of self-reported delinquency among Western Australian male and female high school students: the malefemale gender gap
The Adapted Self-Report Delinquency Scale (ASDS) was administered to 328 adolescents (174 males and 154 females) from eight high schools in Perth, Western Australia. The ages of the sample ranged from 13 to 17 years. Males reported a greater percentage level of involvement than females in 36 of 40 individual delinquent behaviours comprising the ASDS. A between-subjects multivariate analysis of variance using a Bonferroni adjusted alpha revealed a significant multivariate main effect of gender, F(6, 318) = 3.98, p < 0.001, partial η2 = 0.08. No significant main effect of age was evident. Univariate F-tests revealed that males scored significantly higher than females on only one of seven delinquent factors (physical aggression). These data are discussed in light of established evidence showing male predominance in delinquency, recent reports suggesting a male-female gender gap, and theories that have attempted to explain this disparity in offending among males and females
The effectiveness of interventions to change six health behaviours: a review of reviews
Background: Several World Health Organisation reports over recent years have highlighted the high incidence of chronic diseases such as diabetes, coronary heart disease and cancer. Contributory factors include unhealthy diets, alcohol and tobacco use and sedentary lifestyles. This paper reports the findings of a review of reviews of behavioural change interventions to reduce unhealthy behaviours or promote healthy behaviours. We included six different health-related behaviours in the review: healthy eating, physical exercise, smoking, alcohol misuse, sexual risk taking (in young people) and illicit drug use. We excluded reviews which focussed on pharmacological treatments or those which required intensive treatments (e. g. for drug or alcohol dependency).
Methods: The Cochrane Library, Database of Abstracts of Reviews of Effectiveness (DARE) and several Ovid databases were searched for systematic reviews of interventions for the six behaviours (updated search 2008). Two reviewers applied the inclusion criteria, extracted data and assessed the quality of the reviews. The results were discussed in a narrative synthesis.
Results: We included 103 reviews published between 1995 and 2008. The focus of interventions varied, but those targeting specific individuals were generally designed to change an existing behaviour (e. g. cigarette smoking, alcohol misuse), whilst those aimed at the general population or groups such as school children were designed to promote positive behaviours (e. g. healthy eating). Almost 50% (n = 48) of the reviews focussed on smoking (either prevention or cessation). Interventions that were most effective across a range of health behaviours included physician advice or individual counselling, and workplace- and school-based activities. Mass media campaigns and legislative interventions also showed small to moderate effects in changing health behaviours. Generally, the evidence related to short-term effects rather than sustained/longer-term impact and there was a relative lack of evidence on how best to address inequalities.
Conclusions: Despite limitations of the review of reviews approach, it is encouraging that there are interventions that are effective in achieving behavioural change. Further emphasis in both primary studies and secondary analysis (e.g. systematic reviews) should be placed on assessing the differential effectiveness of interventions across different population subgroups to ensure that health inequalities are addressed.</p
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Competing Risks of Cardiovascular Versus Noncardiovascular Death During Long‐Term Follow‐Up After Acute Coronary Syndromes
Background: Understanding the relative risk of cardiovascular versus noncardiovascular death is important for designing clinical trials. These risks may differ depending on patient age, sex, and type of acute coronary syndrome (ACS). Methods and Results: IMPROVE‐IT (Improved Reduction of Outcomes: Vytorin Efficacy International Trial) was a randomized controlled trial of simvastatin plus either ezetimibe or placebo following stabilized ACS. Cause of death was adjudicated by an independent committee. We compared the cumulative incidence of cardiovascular and noncardiovascular death for patients with unstable angina/non‐ST‐segment elevation myocardial infarction (UA/NSTEMI) and ST‐segment elevation myocardial infarction (STEMI), in those <65 and ≥65 years old, and males and females, over 7 years of follow‐up. Of 18 131 patients, the presenting event was STEMI for 5190 (29%) and UA/NSTEMI for 12 941 (71%); 10 173 (56%) patients were <65 years old and 7971 (44%) were ≥65 years old at presentation. UA/NSTEMI patients were older than STEMI patients, with more cardiovascular and noncardiovascular risk factors. In STEMI patients, the cumulative incidence of cardiovascular death was higher for ∼4 years following the index event, after which noncardiovascular death predominated. In UA/NSTEMI patients, the cumulative incidence of cardiovascular death remained higher than noncardiovascular death over the full follow‐up period. Patients ≥65 years old and <65 years old had a higher incidence of cardiovascular death than noncardiovascular death over the entirety of follow‐up. Female patients had a higher incidence of cardiovascular death than noncardiovascular death for ∼6 years following the index event; male patients had a higher incidence of cardiovascular death than noncardiovascular death over the entirety of follow‐up. Conclusions: Among post‐ACS patients enrolled in a long‐term clinical trial, the relative incidence of cardiovascular and noncardiovascular death differed based on type of ACS presentation and sex, but not age. These findings further delineate long‐term prognosis after ACS and should inform the design of future cardiovascular outcomes trials
The clustering of galaxies in the SDSS-III Baryon Oscillation Spectroscopic Survey : baryon acoustic oscillations in the Data Releases 10 and 11 Galaxy samples
We present a one per cent measurement of the cosmic distance scale from the detections of the baryon acoustic oscillations (BAO) in the clustering of galaxies from the Baryon Oscillation Spectroscopic Survey, which is part of the Sloan Digital Sky Survey III. Our results come from the Data Release 11 (DR11) sample, containing nearly one million galaxies and covering approximately 8500 square degrees and the redshift range 0.2 < z < 0.7. We also compare these results with those from the publicly released DR9 and DR10 samples. Assuming a concordance Λ cold dark matter (ΛCDM) cosmological model, the DR11 sample covers a volume of 13 Gpc3 and is the largest region of the Universe ever surveyed at this density. We measure the correlation function and power spectrum, including density-field reconstruction of the BAO feature. The acoustic features are detected at a significance of over 7σ in both the correlation function and power spectrum. Fitting for the position of the acoustic features measures the distance relative to the sound horizon at the drag epoch, rd, which has a value of rd,fid = 149.28 Mpc in our fiducial cosmology. We find DV = (1264 ± 25 Mpc)(rd/rd,fid) at z = 0.32 and DV = (2056 ± 20 Mpc)(rd/rd,fid) at z = 0.57. At 1.0 per cent, this latter measure is the most precise distance constraint ever obtained from a galaxy survey. Separating the clustering along and transverse to the line of sight yields measurements at z = 0.57 of DA = (1421 ± 20 Mpc)(rd/rd,fid) and H = (96.8 ± 3.4 km s−1 Mpc−1)(rd,fid/rd). Our measurements of the distance scale are in good agreement with previous BAO measurements and with the predictions from cosmic microwave background data for a spatially flat CDM model with a cosmological constant.Publisher PDFPeer reviewe
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