| 1. |
- Schael, S, et al.
(författare)
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Precision electroweak measurements on the Z resonance
- 2006
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Ingår i: Physics Reports. - : Elsevier BV. - 0370-1573 .- 1873-6270. ; 427:5-6, s. 257-454
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Forskningsöversikt (refereegranskat)abstract
- We report on the final electroweak measurements performed with data taken at the Z resonance by the experiments operating at the electron-positron colliders SLC and LEP. The data consist of 17 million Z decays accumulated by the ALEPH, DELPHI, L3 and OPAL experiments at LEP, and 600 thousand Z decays by the SLID experiment using a polarised beam at SLC. The measurements include cross-sections, forward-backward asymmetries and polarised asymmetries. The mass and width of the Z boson, m(Z) and Gamma(Z), and its couplings to fermions, for example the p parameter and the effective electroweak mixing angle for leptons, are precisely measured: m(Z) = 91.1875 +/- 0.0021 GeV, Gamma(Z) = 2.4952 +/- 0.0023 GeV, rho(l) = 1.0050 +/- 0.0010, sin(2)theta(eff)(lept) = 0.23153 +/- 0.00016. The number of light neutrino species is determined to be 2.9840 +/- 0.0082, in agreement with the three observed generations of fundamental fermions. The results are compared to the predictions of the Standard Model (SM). At the Z-pole, electroweak radiative corrections beyond the running of the QED and QCD coupling constants are observed with a significance of five standard deviations, and in agreement with the Standard Model. Of the many Z-pole measurements, the forward-backward asymmetry in b-quark production shows the largest difference with respect to its SM expectation, at the level of 2.8 standard deviations. Through radiative corrections evaluated in the framework of the Standard Model, the Z-pole data are also used to predict the mass of the top quark, m(t) = 173(+10)(+13) GeV, and the mass of the W boson, m(W) = 80.363 +/- 0.032 GeV. These indirect constraints are compared to the direct measurements, providing a stringent test of the SM. Using in addition the direct measurements of m(t) and m(W), the mass of the as yet unobserved SM Higgs boson is predicted with a relative uncertainty of about 50% and found to be less than 285 GeV at 95% confidence level. (c) 2006 Elsevier B.V. All rights reserved.
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| 4. |
- Johansson, Boo, et al.
(författare)
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Cognitive abilities in late life, proximity to death and distance from birth
- 2006
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Ingår i: Cognitive abilities in late life, proximity to death and distance from birth. Paper presented at the 18th Nordic Congress in Gerontology, Jyväskylä, Finland..
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Konferensbidrag (refereegranskat)abstract
- Intra-individual change and continuity in cognitive abilities were examined as a conditional function of distance from birth (chronological age) and death in two Swedish population-based samples drawn from the H70 (70+; age-homogenous design) and the OCTO Twin (80+; age-heterogeneous design) studies. Examined cognitive domains included mental speed, memory, fluid, and crystallized abilities Three alternative time-based modelling approaches were used to fit the data a) an age-related approach b) a time-to–death-related approach, and c) a dual time structure component ap-proach including both age- and death-related time components. The death-related time structure accounts better for the data and age-related changes were largely attenuated when accounting for death-related changes, but death-related changes were relatively unaffected by the age-related sources of variance. The results emphasize that the reliance on age as a basic time structure in cognitive aging re-search can be doubtful and the importance of identifying diseases, co-morbidity and other health-related factors that account for cognitive decline in later life. Future studies need to identify and evaluate more specifically the time-related processes that increase the likelihood of death and produce decline in brain and cognitive functioning in later life.
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| 5. |
- Piccinin, M, et al.
(författare)
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Cross-national coordinated analysis (IALSA) of age, sex, and education effects on change in MMSE scores
- 2006
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Ingår i: 59th Annual Scientific Meeting of the Gerontological Society of America, Dallas, TX, USA..
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Konferensbidrag (refereegranskat)abstract
- In a cross-national, multi-study (ALSA, CLS, H-70, HOPE, NAS, OCTO-Twin, LASA) analysis, we systematically address concerns regarding the effect of educational attainment on Mini-Mental Status Exam (MMSE) scores in a descriptive comparison of between-person dif-ferences and within-person age changes. We describe the coordinated analysis process and the first results from the IALSA network. Marked country and birth cohort differences in educa-tional attainment required a flexible modeling approach: median years in school ranged from 6 in LASA and the older Swedish cohorts to 12 in CLS and NAS. For studies with similarly coded education, higher educated participants scored higher and showed less decline. Ignoring the impact of declining health, on average, at age 80, men with six years of education scored between 25 and 27 on the MMSE and declined about 0.3 points per year. Older individuals tend to score lower and decline at a faster rate. Gender differences were mixed.
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| 6. |
- Proctor, D.N, et al.
(författare)
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Longitudinal changes in physical functional performance among the oldest old: insight from a study of Swedish twins
- 2006
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Ingår i: Aging Clinical and Experimental Research. ; 18:6, s. 517-530
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Tidskriftsartikel (refereegranskat)abstract
- The primary purpose was to characterize mean and individual-level patterns of change in physical functional performance over eight years (2 year intervals) in a community dwelling sample of Swedish twins (579 men and women aged 79-96 years at baseline). RESULTS: Mixed linear models revealed linear rates of decline for handgrip strength (grip) and time to complete five chair stands, and accelerating decline for peak expiratory flow rate (PEFR) for both sexes. Significant random effects were found for intercept and time for grip and PEFR tests, indicating differences between participants initially and over time. Individual differ-ences in chairstand performance were significant for initial status only. Age at baseline was predictive of initial status in grip, PEFR and chair performance (women only), but not rate of change. Measures of body size at baseline were predictive of individual variation in initial grip (height), PEFR (weight in men, height in women), and chair performance (height), but had less consistent associations with changes in test performance over time. In the deceased sub-sample (85% of participants), having been further from death was related to less steep de-clines in grip, but not PEFR or chair performance. Twins from the same pair were related in initial status (twin level variance ~30-70%), but they were not generally related in rate of change. CONCLUSIONS: These results indicate that changes in physical functional perform-ance in an elderly, community dwelling population vary across individuals in a test and sex-dependent manner. Constitutional variables (age, sex, body size) are predictive of baseline performance, but explain little variance in change over time. Initial status and rate of change in grip strength had the strongest association with proximity from death, indicating that while PEFR and repeated chair stand time are useful tests to assess function, grip strength appears to be a particularly useful biomarker in the oldest- old.
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| 7. |
- Thorvaldsson, Valgeir, 1976, et al.
(författare)
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Effects of repeated testing in a longitudinal age-homogeneous study of cognitive aging
- 2006
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Ingår i: Journal of Gerontology: Psychological Sciences. ; , s. 348-354
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Tidskriftsartikel (refereegranskat)abstract
- Estimates of gains related to repeated test exposure (retest effects) and within-person cogni-tive changes are confounded in most longitudinal studies because of the nonindependent time structures underlying both processes. Recently developed statistical approaches rely on be-tween-person age differences to estimate effects of repeated testing. This study, however, demonstrates how retest effects can be evaluated at the group level in an age-homogeneous population-based study by use of a sampling-based design approach in which level and change of cognitive performance of previous participants, measured at ages 70, 75, 79, 81, 85, 88, 90, 92, 95, 97, and 99 years, were compared with performances of survivors of a rep-resentative sample identified and drawn from the same original population cohort but invited for the first time at age 85 with subsequent measurements at ages 88, 90, 92, 95, 97, and 99. The comparisons revealed a trend toward retest effects on two out of five cognitive meas-urements. The study demonstrates how a design-based approach can provide valuable in-sights into continuous learning processes embedded in population average aging trajectories that are not confounded with cohort and mortality-related selective attrition
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| 8. |
- Thorvaldsson, Valgeir, 1976, et al.
(författare)
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Estimating the effects of repeated test exposure by a design-based sampling approach
- 2006
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Ingår i: The 2006 Cognitive Aging Conference, Atlanta, GA, USA..
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Konferensbidrag (refereegranskat)abstract
- Estimates of gains related to repeated test exposure and aging-related within-person cognitive changes are confounded in most longitudinal studies because of the nonindependent time structures underlying both processes. Statistical approaches for estimating separate retest effects rely on between-person age differences to estimate effects of repeated testing. This study demonstrates how retest effects can be evaluated at the group-level using a sampling-based design approach where level and change of cognitive performance of previous participants in an age-homogeneous population-based study, measurement at ages 70, 75, 79, 81, 85, 88, 90, 92, 95, 97, and 99, were compared with performances of survivors of a representative sample identified and drawn from of the same original population cohort but invited from the first time at age 85 with subsequent measurements at age 88, 90, 92, 95, 97, and 99. The comparisons revealed a small trend toward retest effects on most of the cognitive measurements. The study demonstrates how a design-based approach can provide valuable insights into continuous learning processes embedded in population average aging trajectories that are not confounded with cohort and mortality-related selective attrition. Implicit assumptions of both statistical and design-based approaches are discussed.
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| 9. |
- Thorvaldsson, Valgeir, 1976, et al.
(författare)
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Onset of terminal decline in cognitive abilities in individuals without dementia.
- 2008
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Ingår i: Neurology. - : Ovid Technologies (Wolters Kluwer Health). - 1526-632X .- 0028-3878. ; 71:12, s. 882-7
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE: To identify time of onset and rate of mortality-related change (terminal decline) in cognitive abilities in later life. METHOD: The sample consisted of 288 individuals without dementia (born 1901-1902) drawn from the population of Göteborg, Sweden. Participants were followed from age 70 until death, with up to 12 measurement occasions on three cognitive abilities. Change-point analysis was performed using an automated piecewise linear mixed modeling approach to identify the inflection point indicating accelerated within-person change related to mortality. A profile likelihood method was used to identify the change point that best fit the data for each of three cognitive abilities. RESULTS: Onset of terminal decline was identified 6.6 years prior to death for verbal ability, 7.8 years for spatial ability, and 14.8 years for perceptual speed. CONCLUSIONS: There is substantial acceleration in cognitive decline many years prior to death among individuals without dementia. Time of onset and rate of terminal decline vary considerably across cognitive abilities.
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| 10. |
- Cébe-Suarez, Stéphanie, et al.
(författare)
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Orf virus VEGF-E NZ2 promotes paracellular NRP-1/VEGFR-2 coreceptor assembly via the peptide RPPR
- 2008
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Ingår i: The FASEB Journal. - : Wiley. - 0892-6638 .- 1530-6860. ; 22:8, s. 3078-3086
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Tidskriftsartikel (refereegranskat)abstract
- Vascular endothelial growth factors (VEGFs) interact with the receptor tyrosine kinases (RTKs) VEGFR-1, -2, and -3; neuropilins (NRPs); and heparan sulfate (HS) proteoglycans. VEGF RTKs signal to downstream targets upon ligand-induced tyrosine phosphorylation, while NRPs and HS act as coreceptors that lack enzymatic activity yet modulate signal output by VEGF RTKs. VEGFs exist in various isoforms with distinct receptor specificity and biological activity. Here, a series of mammalian VEGF-A splice variants and orf virus VEGF-Es, as well as chimeric and mutant VEGF variants, were characterized to determine the motifs required for binding to NRP-1 in the absence (VEGF-E) or presence (VEGF-A(165)) of an HS-binding sequence. We identified the carboxyterminal peptides RPPR and DKPRR as the NRP-1 binding motifs of VEGF-E and VEGF-A, respectively. RPPR had significantly higher affinity for NRP-1 than DKPRR. VEGFs containing an RPPR motif promoted HS-independent coreceptor complex assembly between VEGFR-2 and NRP-1, independent of whether these receptors were expressed on the same or separate cells grown in cocultures. Functional studies showed that stable coreceptor assembly by VEGF correlated with its ability to promote vessel formation in an embryoid body angiogenesis assay.
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