1. |
- Hyvonen, R., et al.
(författare)
-
The likely impact of elevated [CO2], nitrogen deposition, increased temperature and management on carbon sequestration in temperate and boreal forest ecosystems: a literature review
- 2007
-
Ingår i: New Phytologist. - Cambridge : Wiley. - 0028-646X .- 1469-8137. ; 173:3, s. 463-480
-
Forskningsöversikt (refereegranskat)abstract
- Temperate and boreal forest ecosystems contain a large part of the carbon stored on land, in the form of both biomass and soil organic matter. Increasing atmospheric [CO2], increasing temperature, elevated nitrogen deposition and intensified management will change this C store. Well documented single-factor responses of net primary production are: higher photosynthetic rate (the main [CO2] response); increasing length of growing season (the main temperature response); and higher leaf-area index (the main N deposition and partly [CO2] response). Soil organic matter will increase with increasing litter input, although priming may decrease the soil C stock initially, but litter quality effects should be minimal (response to [CO2], N deposition, and temperature); will decrease because of increasing temperature; and will increase because of retardation of decomposition with N deposition, although the rate of decomposition of high-quality litter can be increased and that of low-quality litter decreased. Single-factor responses can be misleading because of interactions between factors, in particular those between N and other factors, and indirect effects such as increased N availability from temperature-induced decomposition. In the long term the strength of feedbacks, for example the increasing demand for N from increased growth, will dominate over short-term responses to single factors. However, management has considerable potential for controlling the C store.
|
|
2. |
- Baezner, H, et al.
(författare)
-
Association of gait and balance disorders with age-related white matter changes: the LADIS study.
- 2008
-
Ingår i: Neurology. - : Ovid Technologies (Wolters Kluwer Health). - 1526-632X .- 0028-3878. ; 70:12, s. 935-42
-
Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE: In the Leukoaraiosis and Disability (LADIS) Study, 11 European centers are evaluating the role of age-related white matter changes (ARWMC) as an independent determinant of the transition to disability in the elderly (65 to 84 years). We aimed at determining the influence of ARWMC on different objective measures of gait and balance. METHODS: Six hundred thirty-nine nondisabled individuals were prospectively enrolled and are being followed-up for 3 years. Subjects are graded in three standardized categories of ARWMC (mild, moderate, and severe) according to central MRI reading. Quantitative tests of gait and balance include the Short Physical Performance Battery (SPPB; range: 0 [poor] to 12 [normal]), a timed 8-m walk, and a timed single leg stance test. RESULTS: In cross-sectional analysis, deficiencies in gait and balance performance were correlated with the severity of ARWMC (SPPB: 10.2 +/- 2.1 in the mild, 9.9 +/- 2.0 in the moderate, 8.9 +/- 2.6 in the severe group; p < 0.001). Walking speed correlated with the severity of ARWMC (1.24 +/- 0.28 m/second in the mild, 1.18 +/- 0.32 m/second in the moderate, and 1.09 +/- 0.31 m/second in the severe group; p < 0.001). Balance was best in individuals with mild ARWMC (single leg stance time: 18.9 +/- 10.8 seconds) compared with moderate and severe ARWMC (16.4 +/- 10.8 and 13.6 +/- 11.2 seconds) (p < 0.001). Physically inactive individuals had a higher risk of a pathologic SPPB score (moderate vs mild ARWMC: odds ratio 1.60, 95% CI 1.02 to 2.52; severe vs mild ARWMC: odds ratio 1.75, 95% CI 1.09 to 2.80). CONCLUSIONS: Our findings support a strong association between the severity of age-related white matter changes and the severity of gait and motor compromise. Physical activity might have the potential to reduce the risk of limitations in mobility.
|
|
3. |
- Blahak, C, et al.
(författare)
-
Deep frontal and periventricular age related white matter changes but not basal ganglia and infratentorial hyperintensities are associated with falls: cross sectional results from the LADIS study.
- 2009
-
Ingår i: Journal of neurology, neurosurgery, and psychiatry. - : BMJ. - 1468-330X .- 0022-3050. ; 80:6, s. 608-13
-
Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Global age related white matter changes (ARWMC) are associated with progressive gait disturbances and falls, hypothesised to result from interruptions of cortico-subcortical circuits controlling balance, posture and locomotion. METHODS: The location of ARWMC in a large cohort of elderly non-disabled individuals with reported falls was analysed, using the cross sectional data of the Leukoaraiosis and Disability (LADIS) study. Detailed anatomical distributions of ARWMC assessed by MRI studies were analysed with respect to falls and balance performance. RESULTS: The severity of global ARWMC was significantly associated with a history of falls in the year prior to study inclusion (22.2% in the mild, 31.6% in the moderate and 37.3% in the severe ARWMC group according to the Fazekas scale; p = 0.002). Analysing the anatomical distribution of ARWMC, using the semiquantitative Scheltens scale, in multivariate analysis, periventricular (p = 0.006) and frontal deep (p = 0.033) ARWMC were independently associated with falls. Furthermore, logistic regression identified frontal deep (p = 0.003) ARWMC, but not basal ganglia and infratentorial hyperintensities, as significantly associated with balance disturbances. CONCLUSION: The association of frontal and periventricular ARWMC with falls supports the hypothesis that interruption of frontal subcortical motor circuits lead to balance disturbances and hence to an increased risk for falls in ARWMC.
|
|
4. |
- Teodorczuk, A., et al.
(författare)
-
White matter changes and late-life depressive symptoms - Longitudinal study
- 2007
-
Ingår i: BRITISH JOURNAL OF PSYCHIATRY. - : Royal College of Psychiatrists. - 0007-1250 .- 1472-1465. ; 191, s. 212-217
-
Tidskriftsartikel (refereegranskat)abstract
- Evidence from cross-sectional studies suggests a link between cerebral age-related white matter changes and depressive symptoms in older people, although the temporal association remains unclear.AimsTo investigate age-related white matter changes on magnetic resonance imaging (MRI) as an independent predictor of depressive symptoms at 1 year after controlling for known confounders.MethodIn a pan-European multicentre study of 639 older adults without significant disability, MRI white matter changes and demographic and clinical variables, including cognitive scores, quality of life, disability and depressive symptoms, were assessed at baseline. Clinical assessments were repeated at 1 year.ResultsUsing logistic regression analysis, severity of white matter changes was shown to independently and significantly predict depressive symptoms at 1 year after controlling for baseline depressive symptoms, quality of life and worsening disability (P<0.01).ConclusionsWhite matter changes pre-date and are associated with the development of depressive symptoms. This has implications for treatment and prevention of depression in later life.
|
|
5. |
- Balocco, C, et al.
(författare)
-
Microwave detection at 110 GHz by nanowires with broken symmetry
- 2005
-
Ingår i: Nano Letters. - : American Chemical Society (ACS). - 1530-6992 .- 1530-6984. ; 5:7, s. 1423-1427
-
Tidskriftsartikel (refereegranskat)abstract
- By using arrays of nanowires with intentionally broken symmetry, we were able to detect microwaves up to 110 GHz at room temperature. This is, to the best of our knowledge, the highest speed that has been demonstrated in different types of novel electronic nanostructures to date. Our experiments showed a rather stable detection sensitivity over a broad frequency range from 100 MHz to 110 GHz. The novel working principle enabled the nanowires to detect microwaves efficiently without a dc bias. In principle, the need for only one high-resolution lithography step and the planar architecture allow an arbitrary number of nanowires to be made by folding a linear array as many times as required over a large area, for example, a whole wafer. Our experiment on 18 parallel nanowires showed a sensitivity of approximately 75 mV dc output/mW of nominal input power of the 110 GHz signal, even though only about 0.4% of the rf power was effectively applied to the structure because of an impedance mismatch. Because this array of nanowires operates simultaneously, low detection noise was achieved, allowing us to detect -25 dBm 110 GHz microwaves at zero bias with a standard setup.
|
|
6. |
|
|
7. |
|
|
8. |
|
|
9. |
- Miranda, B, et al.
(författare)
-
Self-perceived memory impairment and cognitive performance in an elderly independent population with age-related white matter changes.
- 2008
-
Ingår i: Journal of neurology, neurosurgery, and psychiatry. - : BMJ. - 1468-330X .- 0022-3050. ; 79:8, s. 869-73
-
Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVES: To determine whether self-perceived memory impairment is associated with the severity of white matter changes (WMC) and is related to cognitive impairment. METHODS: Data were drawn from the multinational Leukoaraiosis and Disability Study (LADIS), which investigates the impact of WMC on global functioning. WMC severity was rated using the Fazekas scale. Medial temporal lobe atrophy (MTA) was scored visually and mean values were calculated. The neuropsychological battery consisted of the Mini-Mental State Examination, a modified version of the VADAS-Cog, Trail making and Stroop tests. A question about self-perceived memory impairment was used as a measure for presence of memory complaints. Cognitive performance was analysed test-by-test and in three main domains: memory, executive functions and speed/motor control. The Geriatric Depression Scale (GDS) was used as a measure of depressive symptoms. RESULTS: Six hundred and thirty-eight subjects were included in this study. No association was found between memory complaints and the severity of WMC. Subjects with memory complaints (n = 399) had a higher GDS score [t((637)) = -7.15; p<0.02] and performed worse on almost all cognitive tests and on the three cognitive domains. Multiple linear regression showed that the worse performance on the memory domain was associated with memory complaints independently of depressive symptoms, WMC severity and MTA (R(2) = 0.183; F = 17.09, beta = -0.126; p<0.05). CONCLUSION: In a sample of non-disabled elderly subjects with WMC, self-perceived memory impairment is significantly associated with objective memory impairment independently of the WMC severity, depressive symptoms and MTA.
|
|
10. |
|
|