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- Gottsäter, Anders, et al.
(author)
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Cardiovascular autonomic neuropathy associated with carotid atherosclerosis in Type 2 diabetic patients.
- 2003
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In: Diabetic Medicine. - : Wiley. - 1464-5491 .- 0742-3071. ; 20:6, s. 495-499
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Journal article (peer-reviewed)abstract
- AimsTo clarify if cardiovascular autonomic neuropathy is associated with carotid artery atherosclerotic plaques in Type 2 diabetic patients. MethodsCardiovascular autonomic nerve function was related to carotid artery ultrasound in 61 Type 2 diabetic patients 5-6 years after diagnosis of diabetes. ResultsCardiovascular autonomic neuropathy [abnormal age corrected expiration/inspiration (E/I) ratio or acceleration index (AI)] was found in 13/61 (21%) patients. Patients with cardiovascular autonomic neuropathy showed increased degree of stenosis in the common carotid artery (24.6 ± 13.2% vs. 14.7 ± 9.2%; P = 0.014) and a tendency towards a higher plaque score (4.0 ± 1.7 vs. 3.2 ± 1.6; P = 0.064). Controlled for age, AI correlated inversely with degree of stenosis (r = -0.39; P = 0.005), plaque score (r = -0.39; P = 0.005), and mean (r = -0.33; P = 0.018) and maximum (r = -0.39; P = 0.004) intima-media thickness in the common carotid artery. In contrast, E/I ratio correlated only slightly with mean intima-media thickness in the common carotid artery (r = -0.28; P = 0.049). ConclusionsCardiovascular autonomic neuropathy was associated with carotid atherosclerosis in Type 2 diabetic patients. Abnormal E/I ratios reflect efferent structural damage to parasympathetic nerves whereas abnormal AI reflects afferent autonomic dysfunction possibly due to impaired baroreceptor sensitivity secondary to carotid atherosclerosis.
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| 2. |
- Bengtsson, Göran, et al.
(author)
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Irregular walks and loops combines in small-scale movement of a soil insect : implications for dispersal biology
- 2004
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In: Journal of Theoretical Biology. - : Elsevier BV. - 0022-5193 .- 1095-8541. ; 231:2, s. 299-306
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Journal article (peer-reviewed)abstract
- Analysis of small-scale movement patterns of animals we may help to understand and predict movement at a larger scale, such as dispersal, which is a key parameter in spatial population dynamics. We have chosen to study the movement of a soil-dwelling Collembola, Protaphorura armata, in an experimental system consisting of a clay surface with or without physical obstacles. A combination of video recordings, descriptive statistics, and walking simulations was used to evaluate the movement pattern. Individuals were found to link periods of irregular walk with those of looping in ahomogeneous environment as well as in one structured to heterogeneity by physical obstacles. The number of loops varied between 0 and 44 per hour from one individual to another and some individuals preferred to make loops by turning right and others by turning left. P. armata spent less time at the boundary of small obstacles compared to large, presumably because of a lower probability to track the steepness of the curvature as the individual walks along a highly curved surface. Food deprived P. armata had amore winding movement and made more circular loops than those that were well fed. The observed looping behaviour is interpreted in the context of systematic search strategies and compared with similar movement patterns found in other species.
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| 3. |
- Bengtsson, Göran, et al.
(author)
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Statistical analysis of the influence of conspecifics on the dispersal of a soil collembola.
- 2002
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In: Theoretical Population Biology. - : Elsevier BV. - 1096-0325 .- 0040-5809. ; 61:2, s. 97-113
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Journal article (peer-reviewed)abstract
- The evidence for dispersal activity among soil-living invertebrates comes mainly from observations of their movement on artificial substrates or of colonisation of defaunated soils in the field. In an attempt to elucidate the dispersal pattern of soil collembolans in the presence of conspecifics, statistical analyses were undertaken to describe and simulate the movement of groups of Onychiurus armatus released in trays of homogeneous soil. A chi(2) test was used to reject the null hypothesis that individuals moved independently of each other and uniformly in all directions. The mean radial distance moved (1-2 cm day(-1)) and the radial standard deviation varied temporally and with the density of conspecifics. To capture the interaction between the moving individuals, four dispersal models (pure diffusion, diffusion with drift interaction, drift interaction and synchronised diffusion, and drift interaction and behavioural mood), were formulated as stochastic differential equations. The parameters of the models were estimated by minimising the deviance between the observed replicates and replicates that were simulated using the models. The dynamics of movement were best described by modelling the drift interaction as dependent on whether individuals were in a social or an asocial mood.
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| 4. |
- Evans, Chris, et al.
(author)
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Baltic iron and the British iron industry in the eighteenth century
- 2002
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In: Economic history review. - 0013-0117 .- 1468-0289. ; 55:4, s. 642-665
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Journal article (peer-reviewed)abstract
- Before the revolution in coal technology that swept the British iron industry in the last years of the eighteenth century, native ironmasters were unable to meet the burgeoning demand for malleable bar iron. The shortfall was made good by imports of bar iron from the Baltic, first from Sweden, then from Russia. This article presents new empirical evidence on the role played by Baltic iron in the Georgian economy. It also considers the impact of Swedish and Russian iron on domestic ironmasters as they sought organizational, as well as technological, ways to overcome the energy constraints facing the industry.
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