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- McDonnell, J.J., et al.
(författare)
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How old is streamwater? : Open questions in catchment transit time conceptualization, modelling and analysis
- 2010
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Ingår i: Hydrological Processes. - : John Wiley & Sons. - 0885-6087 .- 1099-1085. ; 24:12, s. 1745-1754
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Tidskriftsartikel (refereegranskat)abstract
- The time water spends travelling subsurface through a catchment to the stream network (i.e. the catchment water transit time) fundamentally describes the storage, flow pathway heterogeneity and sources of water in a catchment. The distribution of transit times reflects how catchments retain and release water and solutes that in turn set biogeochemical conditions and affect contamination release or persistence. Thus, quan- tifying the transit time distribution provides an important constraint on biogeochemical processes and catchment sensitivity to anthropogenic inputs, contamination and land-use change. Although the assumptions and limitations of past and present transit time modelling approaches have been recently reviewed (McGuire and McDonnell, 2006), there remain many fundamental research challenges for understanding how transit time can be used to quantify catchment flow processes and aid in the development and testing of rainfall–runoff models. In this Commen- tary study, we summarize what we think are the open research questions in transit time research. These thoughts come from a 3-day workshop in January 2009 at the International Atomic Energy Agency in Vienna. We attempt to lay out a roadmap for this work for the hydrological commu- nity over the next 10 years. We do this by first defining what we mean (qualitatively and quantitatively) by transit time and then organize our vision around needs in transit time theory, needs in field studies of tran- sit time and needs in rainfall – runoff modelling. Our goal in presenting this material is to encourage widespread use of transit time information in process studies to provide new insights to catchment function and to inform the structural development and testing of hydrologic models.
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| 4. |
- Chang, S. M., et al.
(författare)
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Efficacy and safety of angiotensin receptor blockade are not modified by aspirin in patients with chronic heart failure: a cohort study from the Candesartan in Heart failure--Assessment of Reduction in Mortality and morbidity (CHARM) programme
- 2010
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Ingår i: European Journal of Heart Failure. - 1388-9842. ; 12:7, s. 738-745
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Tidskriftsartikel (refereegranskat)abstract
- AIMS: It is unknown whether there is an interaction between aspirin and angiotensin receptor blockers on outcomes in patients with heart failure (HF). METHODS AND RESULTS: The efficacy and safety of candesartan vs. placebo was assessed in 7599 patients with symptomatic HF and reduced or preserved left ventricular ejection fraction enrolled in the CHARM programme according to baseline aspirin use. Patients were randomized to candesartan or matching placebo and were followed for a median of 38 months. Aspirin was used in 4246 (55.9%) of patients at baseline. When compared with placebo, candesartan use was associated with lower event rates for cardiovascular (CV) death or HF hospitalization (primary outcome) in both the aspirin group (28 vs. 31.9%, HR 0.81, 95% CI 0.72-0.90) and non-aspirin group (33 vs. 38%, HR 0.81, 95% CI 0.72-0.91). Baseline aspirin use did not modify the effectiveness of candesartan in reducing the risk of CV death or HF hospitalization in CHARM overall (P = 0.64) or in the CHARM individual trials. In addition, there was no significant interaction between aspirin therapy and candesartan in terms of discontinuation of study drug due to adverse reactions (P = 0.72). CONCLUSION: There appears to be no significant modification of the benefit of candesartan on CV mortality and morbidity outcomes or safety by concomitant use of aspirin in patients with chronic HF.
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- Kim, Dong-Hyun, et al.
(författare)
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Pooled analyses of 13 prospective cohort studies on folate intake and colon cancer
- 2010
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Ingår i: Cancer Causes and Control. - : SPRINGER. - 0957-5243 .- 1573-7225. ; 21:11, s. 1919-1930
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Tidskriftsartikel (refereegranskat)abstract
- Studies of folate intake and colorectal cancer risk have been inconsistent. We examined the relation with colon cancer risk in a series of 13 prospective studies. Study- and sex-specific relative risks (RRs) were estimated from the primary data using Cox proportional hazards models and then pooled using a random-effects model. Among 725,134 participants, 5,720 incident colon cancers were diagnosed during follow-up. The pooled multivariate RRs (95% confidence interval [CI]) comparing the highest vs. lowest quintile of intake were 0.92 (95% CI 0.84-1.00, p-value, test for between-studies heterogeneity = 0.85) for dietary folate and 0.85 (95% CI 0.77-0.95, p-value, test for between-studies heterogeneity = 0.42) for total folate. Results for total folate intake were similar in analyses using absolute intake cutpoints (pooled multivariate RR = 0.87, 95% CI 0.78-0.98, comparing a parts per thousand yen560 mcg/days vs. < 240 mcg/days, p-value, test for trend = 0.009). When analyzed as a continuous variable, a 2% risk reduction (95% CI 0-3%) was estimated for every 100 mu g/day increase in total folate intake. These data support the hypothesis that higher folate intake is modestly associated with reduced risk of colon cancer.
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- Petersen, Gloria M, et al.
(författare)
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A genome-wide association study identifies pancreatic cancer susceptibility loci on chromosomes 13q22.1, 1q32.1 and 5p15.33
- 2010
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Ingår i: Nature Genetics. - : Springer Science and Business Media LLC. - 1061-4036 .- 1546-1718. ; 42:3, s. 224-228
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Tidskriftsartikel (refereegranskat)abstract
- We conducted a genome-wide association study of pancreatic cancer in 3,851 affected individuals (cases) and 3,934 unaffected controls drawn from 12 prospective cohort studies and 8 case-control studies. Based on a logistic regression model for genotype trend effect that was adjusted for study, age, sex, self-described ancestry and five principal components, we identified eight SNPs that map to three loci on chromosomes 13q22.1, 1q32.1 and 5p15.33. Two correlated SNPs, rs9543325 (P = 3.27 x 10(-11), per-allele odds ratio (OR) 1.26, 95% CI 1.18-1.35) and rs9564966 (P = 5.86 x 10(-8), per-allele OR 1.21, 95% CI 1.13-1.30), map to a nongenic region on chromosome 13q22.1. Five SNPs on 1q32.1 map to NR5A2, and the strongest signal was at rs3790844 (P = 2.45 x 10(-10), per-allele OR 0.77, 95% CI 0.71-0.84). A single SNP, rs401681 (P = 3.66 x 10(-7), per-allele OR 1.19, 95% CI 1.11-1.27), maps to the CLPTM1L-TERT locus on 5p15.33, which is associated with multiple cancers. Our study has identified common susceptibility loci for pancreatic cancer that warrant follow-up studies.
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