428 research outputs found
Effect of a multimodal high intensity exercise intervention in cancer patients undergoing chemotherapy: randomised controlled trial
Objective To assess the effect of a multimodal group exercise intervention, as an adjunct to conventional care, on fatigue, physical capacity, general wellbeing, physical activity, and quality of life in patients with cancer who were undergoing adjuvant chemotherapy or treatment for advanced disease
Stable oxygen isotope variability in two contrasting glacier river catchments in Greenland
Analysis of stable oxygen isotope (δ18O) characteristics is a useful tool to investigate water provenance in glacier river systems. In order to attain knowledge on the diversity of δ18O variations in Greenlandic rivers, we examined two contrasting glacierised catchments disconnected from the Greenland Ice Sheet (GrIS). At the Mittivakkat Gletscher river, a small river draining a local temperate glacier in southeast Greenland, diurnal oscillations in δ18O occurred with a 3 h time lag to the diurnal oscillations in run-off. The mean annual δ18O was −14.68 ± 0.18 ‰ during the peak flow period. A hydrograph separation analysis revealed that the ice melt component constituted 82 ± 5 % of the total run-off and dominated the observed variations during peak flow in August 2004. The snowmelt component peaked between 10:00 and 13:00 local time, reflecting the long travel time and an inefficient distributed subglacial drainage network in the upper part of the glacier. At the Kuannersuit Glacier river on the island Qeqertarsuaq in west Greenland, the δ18O characteristics were examined after the major 1995–1998 glacier surge event. The mean annual δ18O was −19.47 ± 0.55 ‰. Despite large spatial variations in the δ18O values of glacier ice on the newly formed glacier tongue, there were no diurnal oscillations in the bulk meltwater emanating from the glacier in the post-surge years. This is likely a consequence of a tortuous subglacial drainage system consisting of linked cavities, which formed during the surge event. Overall, a comparison of the δ18O compositions from glacial river water in Greenland shows distinct differences between water draining local glaciers and ice caps (between −23.0 and −13.7 ‰) and the GrIS (between −29.9 and −23.2 ‰). This study demonstrates that water isotope analyses can be used to obtain important information on water sources and the subglacial drainage system structure that is highly desired for understanding glacier hydrology
The Supernova Legacy Survey 3-year sample: Type Ia Supernovae photometric distances and cosmological constraints
We present photometric properties and distance measurements of 252 high
redshift Type Ia supernovae (0.15 < z < 1.1) discovered during the first three
years of the Supernova Legacy Survey (SNLS). These events were detected and
their multi-colour light curves measured using the MegaPrime/MegaCam instrument
at the Canada-France-Hawaii Telescope (CFHT), by repeatedly imaging four
one-square degree fields in four bands. Follow-up spectroscopy was performed at
the VLT, Gemini and Keck telescopes to confirm the nature of the supernovae and
to measure their redshifts. Systematic uncertainties arising from light curve
modeling are studied, making use of two techniques to derive the peak
magnitude, shape and colour of the supernovae, and taking advantage of a
precise calibration of the SNLS fields. A flat LambdaCDM cosmological fit to
231 SNLS high redshift Type Ia supernovae alone gives Omega_M = 0.211 +/-
0.034(stat) +/- 0.069(sys). The dominant systematic uncertainty comes from
uncertainties in the photometric calibration. Systematic uncertainties from
light curve fitters come next with a total contribution of +/- 0.026 on
Omega_M. No clear evidence is found for a possible evolution of the slope
(beta) of the colour-luminosity relation with redshift.Comment: (The SNLS Collaboration) 40 pages, 32 figures, Accepted in A&
Prospects and pitfalls of gravitational lensing in large supernova surveys
To investigate the effect of gravitational lensing of supernovae in large
ongoing surveys, we simulate the effect of gravitational lensing magnification
on individual supernovae using observational data input from two large
supernova surveys. To estimate the magnification due to matter in the
foreground, we simulate galaxy catalogs and compute the magnification along
individual lines of sight using the multiple lens plane algorithm. The dark
matter haloes of the galaxies are modelled as gravitational lenses using
singular isothermal sphere or Navarro-Frenk-White profiles. Scaling laws
between luminosity and mass, provided by Faber-Jackson and Tully-Fisher
relations, are used to estimate the masses of the haloes.
While our simulations show that the SDSSII supernova survey is marginally
affected by gravitational lensing, we find that the effect will be measurable
in the SNLS survey that probes higher redshifts. Our simulations show that the
probability to measure a significant (3 sigma) correlation between the Hubble
diagram residuals and the calculated lensing magnification is ~95% in the SNLS
data. Moreover, with this data it should be possible to constrain the
normalisation of the masses of the lensing galaxy haloes at the 1 sigma and 2
sigma confidence level with ~30% and ~60% accuracy, respectively.Comment: 7 pages, 4 figures, submitted to A &
Supernova Legacy Survey: Using Spectral Signatures To Improve Type Ia Supernovae As Distance Indicators
GMOS optical long-slit spectroscopy at the Gemini-North telescope was used to
classify targets from the Supernova Legacy Survey (SNLS) from July 2005 and May
2006 - May 2008. During this time, 95 objects were observed. Where possible the
objects' redshifts (z) were measured from narrow emission or absorption
features in the host galaxy spectrum, otherwise they were measured from the
broader supernova features. We present spectra of 68 confirmed or probable SNe
Ia from SNLS with redshifts in the range 0.17 \leq z \leq 1.02. In combination
with earlier SNLS Gemini and VLT spectra, we used these new observations to
measure pseudo-equivalent widths (EWs) of three spectral features - CaII H&K,
SiII and MgII - in 144 objects and compared them to the EWs of low-redshift SNe
Ia from a sample drawn from the literature. No signs of changes with z are seen
for the CaII H&K and MgII features. Systematically lower EW SiII is seen at
high redshift, but this can be explained by a change in demographics of the SNe
Ia population within a two-component model combined with an observed
correlation between EW SiII and photometric lightcurve stretch.Comment: 49 pages including 2 online-only appendices, accepted for publication
in MNRA
SNLS3: Constraints on Dark Energy Combining the Supernova Legacy Survey Three Year Data with Other Probes
We present observational constraints on the nature of dark energy using the
Supernova Legacy Survey three year sample (SNLS3) of Guy et al. (2010) and
Conley et al. (2011). We use the 472 SNe Ia in this sample, accounting for
recently discovered correlations between SN Ia luminosity and host galaxy
properties, and include the effects of all identified systematic uncertainties
directly in the cosmological fits. Combining the SNLS3 data with the full WMAP7
power spectrum, the Sloan Digital Sky Survey luminous red galaxy power
spectrum, and a prior on the Hubble constant H0 from SHOES, in a flat universe
we find omega_m=0.269+/-0.015 and w=-1.061+0.069-0.068 -- a 6.5% measure of the
dark energy equation-of-state parameter w. The statistical and systematic
uncertainties are approximately equal, with the systematic uncertainties
dominated by the photometric calibration of the SN Ia fluxes -- without these
calibration effects, systematics contribute only a ~2% error in w. When
relaxing the assumption of flatness, we find omega_m=0.271+/-0.015,
omega_k=-0.002+/-0.006, and w=-1.069+0.091-0.092. Parameterizing the time
evolution of w as w(a)=w_0+w_a(1-a), gives w_0=-0.905+/-0.196,
w_a=-0.984+1.094-1.097 in a flat universe. All of our results are consistent
with a flat, w=-1 universe. The size of the SNLS3 sample allows various tests
to be performed with the SNe segregated according to their light curve and host
galaxy properties. We find that the cosmological constraints derived from these
different sub-samples are consistent. There is evidence that the coefficient,
beta, relating SN Ia luminosity and color, varies with host parameters at
>4sigma significance (in addition to the known SN luminosity--host relation);
however this has only a small effect on the cosmological results and is
currently a sub-dominant systematic.Comment: Accepted for publication in ApJ. Data available from
https://tspace.library.utoronto.ca/snl
Faecal occult blood screening and reduction of colorectal cancer mortality: a case-control study
To estimate the efficacy of screening on colorectal cancer mortality, a population-based case–control study was conducted in well-defined areas of Burgundy (France). Screening by faecal occult blood test prior to diagnosis in cases born between 1914 and 1943 and who died of colorectal cancer diagnosed in 1988–94 was compared with screening in controls matched with the case for age, sex and place of residence. Cases were less likely to have been screened than controls, with an odds ratio (OR) of 0.67 [95% confidence interval (CI) 0.48–0.94]. The negative overall association did not differ by gender or by anatomical location. The odds ratio of death from colorectal cancer was 0.64 (95% CI 0.46–0.91) for those screened within 3 years of case diagnosis compared with those not screened. It was 1.14 (95% CI 0.50–2.63) for those screened more than 3 years before case diagnosis. There was a negative association between the risk of death from colorectal cancer and the number of participations in the screening campaigns. The inverse association between screening for faecal occult blood and fatal colorectal cancer suggests that screening can reduce colorectal cancer mortality. This report further supports recommendations for population-based mass screening with faecal occult blood test. © 1999 Cancer Research Campaig
The uptake and effect of a mailed multi-modal colon cancer screening intervention: A pilot controlled trial
Abstract Background We sought to determine whether a multi-modal intervention, which included mailing a patient reminder with a colon cancer decision aid to patients and system changes allowing direct access to scheduling screening tests through standing orders, would be an effective and efficient means of promoting colon cancer screening in primary care practice. Methods We conducted a controlled trial comparing the proportion of intervention patients who received colon cancer screening with wait list controls at one practice site. The intervention was a mailed package that included a letter from their primary care physician, a colon cancer screening decision aid, and instructions for obtaining each screening test without an office visit so that patients could access screening tests directly. Major outcomes were screening test completion and cost per additional patient screened. Results In the intervention group, 15% (20/137) were screened versus 4% (4/100) in the control group (difference 11%; (95%; CI 3%;18% p = 0.01). The cost per additional patient screened was estimated to be $94. Conclusion A multi-modal intervention, which included mailing a patient reminder with a colon cancer decision aid to patients and system changes allowing patients direct access to schedule screening tests, increased colon cancer screening test completion in a subset of patients within a single academic practice. Although the uptake of the decision aid was low, the cost was also modest, suggesting that this method could be a viable approach to colon cancer screening
Prevalence, predictors and prognostic implications of PR interval prolongation in patients with heart failure
Aims:
To determine the prevalence, incidence, predictors and prognostic implications of PR interval prolongation in patients referred with suspected heart failure.
Methods and Results:
Consecutive patients referred with suspected heart failure were prospectively enrolled. After excluding patients with implantable cardiac devices and atrial fibrillation, 1420 patients with heart failure and reduced ejection fraction (HeFREF) [age: median 71 (interquartile range IQR: 63-78) years; men: 71%; NT-ProBNP: 1319 (583-3378) ng/L], 1094 with heart failure and normal ejection fraction (HeFNEF) [age: 76 (70-82) years; men: 47%; NT-ProBNP: 547 (321-1171) ng/L], and 1150 without heart failure [age: 68 (60-75) years; men: 51%; NT-ProBNP: 86 (46-140) ng/L] were included.
The prevalence of first degree heart block [heart-rate corrected PR interval (PRc) >200 ms] was higher in patients with heart failure (21% HeFREF, 20% HeFNEF, 9% without heart failure). In patients with HeFREF or HeFNEF, longer baseline PRc was associated with greater age, male sex, and longer QRS duration and, in those with HeFREF, treatment with amiodarone or digoxin.
Patients with heart failure in the longest PRc quartile had worse survival compared to shorter PRc quartiles but PRc was not independently associated with survival in multivariable analysis. For patients without heart failure, shorter baseline PRc was independently associated with worse survival.
Conclusion:
PRc prolongation is common in patients with HeFREF or HeFNEF and associated with worse survival, although not an independent predictor of outcome. The results of clinical trials investigating the therapeutic potential of shortening the PR interval by pacing are awaited
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