| 1. |
- Abend, Sven, et al.
(författare)
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Terrestrial very-long-baseline atom interferometry : Workshop summary
- 2024
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Ingår i: AVS Quantum Science. - : American Institute of Physics (AIP). - 2639-0213. ; 6:2
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Forskningsöversikt (refereegranskat)abstract
- This document presents a summary of the 2023 Terrestrial Very-Long-Baseline Atom Interferometry Workshop hosted by CERN. The workshop brought together experts from around the world to discuss the exciting developments in large-scale atom interferometer (AI) prototypes and their potential for detecting ultralight dark matter and gravitational waves. The primary objective of the workshop was to lay the groundwork for an international TVLBAI proto-collaboration. This collaboration aims to unite researchers from different institutions to strategize and secure funding for terrestrial large-scale AI projects. The ultimate goal is to create a roadmap detailing the design and technology choices for one or more kilometer--scale detectors, which will be operational in the mid-2030s. The key sections of this report present the physics case and technical challenges, together with a comprehensive overview of the discussions at the workshop together with the main conclusions.
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| 2. |
- Dyrby, Tim B, et al.
(författare)
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Segmentation of age-related white matter changes in a clinical multi-center study.
- 2008
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Ingår i: NeuroImage. - : Elsevier BV. - 1053-8119. ; 41:2, s. 335-45
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Tidskriftsartikel (refereegranskat)abstract
- Age-related white matter changes (WMC) are thought to be a marker of vascular pathology, and have been associated with motor and cognitive deficits. In the present study, an optimized artificial neural network was used as an automatic segmentation method to produce probabilistic maps of WMC in a clinical multi-center study. The neural network uses information from T1- and T2-weighted and fluid attenuation inversion recovery (FLAIR) magnetic resonance (MR) scans, neighboring voxels and spatial location. Generalizability of the neural network was optimized by including the Optimal Brain Damage (OBD) pruning method in the training stage. Six optimized neural networks were produced to investigate the impact of different input information on WMC segmentation. The automatic segmentation method was applied to MR scans of 362 non-demented elderly subjects from 11 centers in the European multi-center study Leukoaraiosis And Disability (LADIS). Semi-manually delineated WMC were used for validating the segmentation produced by the neural networks. The neural network segmentation demonstrated high consistency between subjects and centers, making it a promising technique for large studies. For WMC volumes less than 10 ml, an increasing discrepancy between semi-manual and neural network segmentation was observed using the similarity index (SI) measure. The use of all three image modalities significantly improved cross-center generalizability compared to neural networks using the FLAIR image only. Expert knowledge not available to the neural networks was a minor source of discrepancy, while variation in MR scan quality constituted the largest source of error.
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| 3. |
- Gouw, Alida A, et al.
(författare)
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On the etiology of incident brain lacunes: longitudinal observations from the LADIS study.
- 2008
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Ingår i: Stroke; a journal of cerebral circulation. - 1524-4628. ; 39:11, s. 3083-5
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND AND PURPOSE: We investigated regional differences in MRI characteristics and risk factor profiles of incident lacunes over a 3-year period. METHODS: Baseline and 3-year follow-up MRI were collected within the LADIS study (n=358). Incident lacunes were characterized with respect to brain region, their appearance within pre-existent white matter hyperintensities (WMH), surrounding WMH size, and risk factors. RESULTS: 106 incident lacunes were observed in 62 patients (58 subcortical white matter [WM], 35 basal ganglia, and 13 infratentorial). Incident subcortical WM lacunes occurred more often within preexisting WMH (P=0.01) and were mostly accompanied by new and expanded WMH (P<0.001), compared to incident basal ganglia and infratentorial lacunes. Risk factors for incident subcortical WM lacunes were history of hypertension and stroke, whereas atrial fibrillation predicted incident basal ganglia/infratentorial lacunes. CONCLUSIONS: Differences in relation to WMH and risk factor profiles may suggest that incident lacunes in the subcortical WM have a different pathogenesis than those in the basal ganglia and infratentorial region.
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| 4. |
- Gouw, Alida A, et al.
(författare)
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Progression of white matter hyperintensities and incidence of new lacunes over a 3-year period: the Leukoaraiosis and Disability study.
- 2008
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Ingår i: Stroke; a journal of cerebral circulation. - 1524-4628. ; 39:5, s. 1414-20
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND AND PURPOSE: We studied the natural course of white matter hyperintensities (WMH) and lacunes, the main MRI representatives of small vessel disease, over time and evaluated possible predictors for their development. METHODS: Baseline and repeat MRI (3-year follow-up) were collected within the multicenter, multinational Leukoaraiosis and Disability study (n=396). Baseline WMH were scored on MRI by the Fazekas scale and the Scheltens scale. WMH progression was assessed using the modified Rotterdam Progression scale (absence/presence of progression in 9 brain regions). Baseline and new lacunes were counted per region. WMH and lacunes at baseline and vascular risk factors were evaluated as predictors of WMH progression and new lacunes. RESULTS: WMH progressed (mean+/-SD=1.9+/-1.8) mostly in the subcortical white matter, where WMH was also most prevalent at baseline. The majority of new lacunes, which were found in 19% of the subjects (maximum=9), also appeared in the subcortical white matter, mainly of the frontal lobes, whereas most baseline lacunes were located in the basal ganglia. Baseline WMH and lacunes predicted both WMH progression and new lacunes. Furthermore, previous stroke, diabetes, and blood glucose were risk factors for WMH progression. Male sex, hypertension, systolic blood pressure, previous stroke, body mass index, high-density lipoprotein, and triglyceride levels were risk factors for new lacunes. CONCLUSIONS: WMH and lacunes progressed over time, predominantly in the subcortical white matter. Progression was observed especially in subjects with considerable WMH and lacunes at baseline. Moreover, the presence of vascular risk factors at baseline predicted WMH progression and new lacunes over a 3-year period.
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| 5. |
- Ikram, M. Arfan, et al.
(författare)
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Common variants at 6q22 and 17q21 are associated with intracranial volume
- 2012
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Ingår i: Nature Genetics. - : Springer Science and Business Media LLC. - 1061-4036 .- 1546-1718. ; 44:5, s. 539-544
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Tidskriftsartikel (refereegranskat)abstract
- During aging, intracranial volume remains unchanged and represents maximally attained brain size, while various interacting biological phenomena lead to brain volume loss. Consequently, intracranial volume and brain volume in late life reflect different genetic influences. Our genome-wide association study (GWAS) in 8,175 community-dwelling elderly persons did not reveal any associations at genome-wide significance (P < 5 x 10(-8)) for brain volume. In contrast, intracranial volume was significantly associated with two loci: rs4273712 (P = 3.4 x 10(-11)), a known height-associated locus on chromosome 6q22, and rs9915547 (P = 1.5 x 10(-12)), localized to the inversion on chromosome 17q21. We replicated the associations of these loci with intracranial volume in a separate sample of 1,752 elderly persons (P = 1.1 x 10(-3) for 6q22 and 1.2 x 10(-3) for 17q21). Furthermore, we also found suggestive associations of the 17q21 locus with head circumference in 10,768 children (mean age of 14.5 months). Our data identify two loci associated with head size, with the inversion at 17q21 also likely to be involved in attaining maximal brain size.
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| 6. |
- Jokinen, Hanna, et al.
(författare)
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Longitudinal cognitive decline in subcortical ischemic vascular disease--the LADIS Study.
- 2009
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Ingår i: Cerebrovascular diseases (Basel, Switzerland). - : S. Karger AG. - 1421-9786 .- 1015-9770. ; 27:4, s. 384-91
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Cross-sectional studies have indicated that subcortical ischemic vascular disease (SIVD), as defined according to imaging criteria, is associated with a specific clinical and cognitive profile. Much less is known about the long-term cognitive consequences of SIVD. The aim of the study was to investigate the longitudinal cognitive performance and incident dementia in subjects with and without SIVD in a sample of older adults with white matter lesions. METHODS: In the Leukoaraiosis and Disability (LADIS) study, 639 participants were examined with annual clinical and neuropsychological evaluations for 3 years. The subjects meeting the MRI criteria of SIVD at baseline were compared to the other subjects of the sample with linear mixed models. RESULTS: The overall level of cognitive performance over the follow-up period was inferior in multiple cognitive domains in SIVD subjects as compared to the reference group. The subjects with SIVD presented significantly steeper decline of performance in the Stroop test (parts I and II), Trail Making A test, Verbal fluency test, and Mini-Mental State Examination. They also had a threefold risk of developing dementia during follow-up independently of age, sex, education and medial temporal lobe atrophy. CONCLUSIONS: SIVD, as a manifestation of cerebral small vessel disease, is related to progressive cognitive impairment and a considerable risk of developing dementia. SIVD seems to specifically contribute to the deterioration of psychomotor speed, executive control, and global cognitive function.
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| 7. |
- Jokinen, Hanna, et al.
(författare)
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MRI-defined subcortical ischemic vascular disease: baseline clinical and neuropsychological findings. The LADIS Study.
- 2009
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Ingår i: Cerebrovascular diseases (Basel, Switzerland). - : S. Karger AG. - 1421-9786 .- 1015-9770. ; 27:4, s. 336-44
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Subcortical ischemic vascular disease (SIVD) is a common, but often overlooked cause of vascular cognitive impairment. Diagnostic research criteria for SIVD are based on magnetic resonance imaging (MRI) findings including substantial white matter lesions (WML) and multiple lacunar infarcts. Empirical studies validating these imaging criteria are still few. The purpose of the study was to describe the clinical and cognitive characteristics of the MRI-defined SIVD in a mixed sample of functionally independent elderly subjects with WML. METHODS: The subjects of the Leukoaraiosis and Disability (LADIS) study, aged 65-84 years, underwent comprehensive clinical and neuropsychological examinations, and brain MRI at the baseline assessment. The subjects meeting the SIVD imaging criteria (n = 89) were compared to the other subjects of the sample (n = 524). RESULTS: SIVD was associated with lower education, hypertension and, independently, with obesity. The subjects with SIVD had more often motor impairment, a history of falls, and subtle impairment in activities of daily living, but they did not differ for depressive symptoms. SIVD subjects performed significantly inferiorly in tests of global cognitive function, psychomotor speed, attention and executive functions, verbal fluency, and working memory. CONCLUSION: In this population of nondisabled older adults with WML, SIVD was related to specific clinical and functional characteristics. Neuropsychological features included psychomotor slowing as well as deficits in attention and executive functions.
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| 8. |
- Metcalfe, Travis S., et al.
(författare)
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Magnetic and Rotational Evolution of rho CrB from Asteroseismology with TESS
- 2021
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Ingår i: Astrophysical Journal. - : Institute of Physics Publishing (IOPP). - 0004-637X .- 1538-4357. ; 921:2
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Tidskriftsartikel (refereegranskat)abstract
- During the first half of main-sequence lifetimes, the evolution of rotation and magnetic activity in solar-type stars appears to be strongly coupled. Recent observations suggest that rotation rates evolve much more slowly beyond middle age, while stellar activity continues to decline. We aim to characterize this midlife transition by combining archival stellar activity data from the Mount Wilson Observatory with asteroseismology from the Transiting Exoplanet Survey Satellite (TESS). For two stars on opposite sides of the transition (88 Leo and rho CrB), we independently assess the mean activity levels and rotation periods previously reported in the literature. For the less active star (rho CrB), we detect solar-like oscillations from TESS photometry, and we obtain precise stellar properties from asteroseismic modeling. We derive updated X-ray luminosities for both stars to estimate their mass-loss rates, and we use previously published constraints on magnetic morphology to model the evolutionary change in magnetic braking torque. We then attempt to match the observations with rotational evolution models, assuming either standard spin-down or weakened magnetic braking. We conclude that the asteroseismic age of rho CrB is consistent with the expected evolution of its mean activity level and that weakened braking models can more readily explain its relatively fast rotation rate. Future spectropolarimetric observations across a range of spectral types promise to further characterize the shift in magnetic morphology that apparently drives this midlife transition in solar-type stars.
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| 9. |
- Pantoni, Leonardo, et al.
(författare)
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Leukoaraiosis predicts hidden global functioning impairment in nondisabled older people: the LADIS (Leukoaraiosis and Disability in the Elderly) Study.
- 2006
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Ingår i: Journal of the American Geriatrics Society. - : Wiley. - 0002-8614 .- 1532-5415. ; 54:7, s. 1095-101
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVES: To determine whether leukoaraiosis severity is independently associated with differences in global functioning in nondisabled elderly patients. DESIGN: Cross-sectional data analysis from an ongoing longitudinal multicenter and multinational study. SETTING: The Leukoaraiosis and Disability Study, a collaboration aimed at assessing leukoaraiosis as an independent predictor of the transition to disability in older people. PARTICIPANTS: Six hundred thirty-nine nondisabled subjects (288 men, 351 women, mean age+/-standard deviation 74.1+/-5.0) with magnetic resonance imaging-detected leukoaraiosis of different severity and presenting with one of the following: mild cognitive or motor disturbances, minor cerebrovascular events, or mood alterations or in whom leukoaraiosis was incidentally identified. MEASUREMENTS: Centralized assessment of leukoaraiosis severity according to the three severity degrees of the Fazekas scale; Disability Assessment for Dementia (DAD) Scale for measurement of global functioning. RESULTS: At baseline, 44% of participants had a mild, 31% a moderate, and 25% a severe degree of leukoaraiosis. A significant trend toward declining performance on the DAD Scale was apparent with increasing leukoaraiosis score severity (total score=98.8, 98.6, 97.5, respectively, in the three leukoaraiosis categories, analysis of variance P=.002). Similar trends were obtained for basic (P=.01) and instrumental (P<.001) function items. The statistical significance of these differences was confirmed in a multiple linear regression analysis correcting for numerous factors known to influence disability in older people. Executive function test performance declined along with increasing leukoaraiosis severity and was significantly related to DAD total score. CONCLUSION: Even in nondisabled elderly patients, levels of functional ability are related to white matter lesion severity. Executive dysfunction may mediate this relationship.
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| 10. |
- Ropele, Stefan, et al.
(författare)
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Quantitation of brain tissue changes associated with white matter hyperintensities by diffusion-weighted and magnetization transfer imaging: the LADIS (Leukoaraiosis and Disability in the Elderly) study.
- 2009
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Ingår i: Journal of magnetic resonance imaging : JMRI. - : Wiley. - 1053-1807 .- 1522-2586. ; 29:2, s. 268-74
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Tidskriftsartikel (refereegranskat)abstract
- PURPOSE: To explore the value of diffusion-weighted imaging (DWI) and magnetization transfer imaging (MTI) for the improved detection and quantification of cerebral tissue changes associated with ageing and white matter hyperintensities (WMH). MATERIALS AND METHODS: DWI (n = 340) and MTI (n = 177) were performed in nine centers of the multinational Leukoaraiosis And DISability (LADIS) study investigating the impact of WMH on 65- to 85-year-old individuals without prior disability. We assessed the apparent diffusion coefficient (ADC) and magnetization transfer ratio (MTR) of normal appearing brain tissue (NABT) and within WMH and related them to subjects' age and WHM severity according to the Fazekas score. RESULTS: ADC and MTR values showed a significant inter-site variation, which was stronger for the MTR. After z-transformation multiple regression analysis revealed WMH severity and age as significant predictors of global ADC and MTR changes. Only lesional ADC, but not MTR was related to WMH severity. CONCLUSION: ADC and MTR are both sensitive for age and WMH related changes in NABT. The ADC is more sensitive for tissue changes within WMH and appears to be more robust for multicenter settings.
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| 11. |
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| 12. |
- Taal, H. Rob, et al.
(författare)
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Common variants at 12q15 and 12q24 are associated with infant head circumference
- 2012
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Ingår i: Nature Genetics. - : Springer Science and Business Media LLC. - 1061-4036 .- 1546-1718. ; 44:5, s. 532-538
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Tidskriftsartikel (refereegranskat)abstract
- To identify genetic variants associated with head circumference in infancy, we performed a meta-analysis of seven genome-wide association studies (GWAS) (N = 10,768 individuals of European ancestry enrolled in pregnancy and/or birth cohorts) and followed up three lead signals in six replication studies (combined N = 19,089). rs7980687 on chromosome 12q24 (P = 8.1 x 10(-9)) and rs1042725 on chromosome 12q15 (P = 2.8 x 10(-10)) were robustly associated with head circumference in infancy. Although these loci have previously been associated with adult height(1), their effects on infant head circumference were largely independent of height (P = 3.8 x 10(-7) for rs7980687 and P = 1.3 x 10(-7) for rs1042725 after adjustment for infant height). A third signal, rs11655470 on chromosome 17q21, showed suggestive evidence of association with head circumference (P = 3.9 x 10(-6)). SNPs correlated to the 17q21 signal have shown genome-wide association with adult intracranial volume(2), Parkinson's disease and other neurodegenerative diseases(3-5), indicating that a common genetic variant in this region might link early brain growth with neurological disease in later life.
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