54 research outputs found
Depositiemodule en correctiefactor in Lagrangiaans EMEP-model
No full textAvailable at the Metheorological Synthesizing Centre-West, DNMI, P.O. Box 43, Blindern, N-0313 Oslo 3, Norway<br>This report provides a description of the new parameterisation of the dry deposition processes that has been included in the Lagrangian acid deposition model of the Meteorological Synthesizing Centre - West of EMEP. The new parameterisation includes a state-of-art method for calculating dry deposition velocities that depend on the actual land use data. This method has been developed at the National Institute of Public Health and the Environment (RIVM), the Netherlands. The Implementation of the method in the EMEP model was carried out in cooperation with RIVM and the University of Bergen, Norway. In addition to the deposition velocity, a new procedure for the local-scale deposition correction developed earlier at the MSC-W was implemented in the model.DGM/L
The ELANA technique: Constructing a high flow bypass using a non-occlusive anastomosis on the ICA and a conventional anastomosis on the SCA in the treatment of a fusiform giant basilar trunk aneurysm
No full textA patient with a partially thrombosed fusiform giant basilar trunk aneurysm presented with devastating headache and symptoms of progressive brain stem compression. Having an aneurysm inaccessible for endovascular treatment, and after failing a vertebral artery balloon occlusion test, he was offered bypass surgery in order to exclude the aneurysm from the cerebral circulation and relieve his symptoms. A connection between the intracranial internal carotid artery and the superior cerebellar artery was created whereupon the basilar artery was ligated just distally to the aneurysm. The proximal anastomosis on the internal carotid artery was made using the excimer laser-assisted non-occlusive anastomosis (ELANA) technique, while a conventional end-to-side anastomosis was used for the distal anastomosis on the superior cerebellar artery. Intra-operative flowmetry showed a flow through the bypass of 40 ml/min after ligation of the basilar artery. An angiogram 24 hours later showed normal filling of the bypass and the vessels supplied by it, but also disclosed a subtotal occlusion of the proximal ipsilateral middle cerebral artery with delayed filling distally. The patient, who had a known thrombogenic coagulopathy, died the following day. Autopsy showed no signs of ischemia in the territories supplied by the bypass, but a thrombus in the proximal middle cerebral artery and massive acute hemorrhagic infarction with swelling in its territory and uncal herniation. Multiple fresh thrombi were found in the lungs. The ELANA anastomosis showed re-endothelialisation without thrombus formation on the inside
Fit Minded College Edition-Podcasts: Feasibility of using a Facebook page to promote physical activity in female college students as compared to a website discussion board
No full textabstract: Background: The purpose of this study was to determine the feasibility of using Facebook as compared to a discussion board in an online, web-based intervention, Fit Minded College Edition-Podcasts (FMCEP), to improve physical activity and self-worth in female college students.
Methods: Participants (n=55) were randomly assigned to either a private Facebook group (FB) or the Fit Minded discussion board (DB) to participate in discussion of health and wellness related podcasts. FMCEP was a 6-week intervention guided by the self-determination theory (SDT) to target autonomy, relatedness and competence. Each week participants were instructed to complete three tasks: (1) listen to an assigned podcast, (2) complete a workbook assignment, and (3) participate in FB or DB online discussion. Participants completed assessments at baseline and post-intervention (6-weeks).
Results: Self-reported physical activity (p=0.032, η2= 0.193) and physical self-worth (p<0.001, η2=0.747) increased significantly over time, but no difference was seen between the groups for both physical activity (p=0.266, η2= 0.056) and physical self-worth (p=0.485, η2=0.024). Website use (measured by mean number of engagements per day, each week) declined across the 6-week intervention in the DB group but was consistent in the FB group.
Conclusion: These findings suggest web-based interventions, guided by SDT, can improve physical activity and physical self-worth among female college students, and the Facebook group may be more feasible and effective. Future studies are needed to optimize web-based physical activity interventions in college females
Hydrodynamic-sea ice couplings in the Barents Sea and their consequences for marine productivity
No full textNo abstracts are to be cited without prior reference to the author. During the past decades the Barents Sea experienced pronounced changes in hydrodynamic-, biogeochemical and higher trophic level conditions. The sea ice cover showed a long-term decreasing trend, which seems to have slightly stabilized during the recent years (Karaskov et al., 2013). Barents Sea temperature is characterized by significant multidecadal variability, which correlates to the Atlantic Multidecadal Oscillation AMO (e.g. Levitus, et al., 2009) and covariations with cyclone activity have been identified in earlier studies (e.g. Sorteberg and Kvingedal, 2006). These long-term variations in oceanographic conditions are accompanied by pronounced variations in the ecosystem with a.o. an increase in fish abundance and an expansion of key stocks northwards (e.g. Stiansen et al., 2009). Based on model simulations of contrasting years, it has earlier been suggested that sea ice retreat will result in increasing primary production in the Barents Sea (e.g. Wassmann et al., 2006). We investigate long-term variations in bottom up controls on the lower trophic level production in the Barents Sea by employing a regional physical-biological model for a multi-decadal simulation. We will illustrate the impact of climatic forcing on lower trophic level production in the Barents Sea and discuss the variations in dominant climatic drivers over the decades
Cerebral autoregulation dynamics in humans
No full textWe studied the response of cerebral blood flow to acute step decreases in arterial blood pressure noninvasively and nonpharmacologically in 10 normal volunteers during normocapnia, hypo-capnia, and hypercapnia. The step (approximately 20 mm Hg) was induced by rapidly deflating thigh blood pressure cuffs following a 2-minute inflation above systolic blood pressure. Instantaneous arterial blood pressure was measured by a new servo-cuff method, and cerebral blood flow changes were assessed by transcranial Doppler recording of middle cerebral artery blood flow velocity. In hypocapnia, full restoration of blood flow to the pretest level was seen as early as 4.1 seconds after the step decrease in blood pressure, while the response was slower in normocapnia and hypercapnia. The time course of cerebrovascular resistance was calculated from blood pressure and blood flow recordings, and rate of regulation was determined as the normalized change in cerebrovascular resistance per second during 2.5 seconds just after the step decrease in blood pressure. The reference for normalization was the calculated change in cerebrovascular resistance that would have nullified the effects of the step decrease in arterial blood pressure on cerebral blood flow. The rate of regulation was 0.38, 0.20, and 0.11/sec in hypocapnia, normocapnia, and hypercapnia, respectively. There was a highly significan
Cognitive Functioning and Health Related Quality of Life after Treatment of Intracranial
No full textCognitive Functioning and Health Related Quality of Life after Treatment of Intracranial Aneurysms Background: Each year between 8 and 10 per 100 000 people in Norway will suffer an aneurysmal subarachnoid hemorrhage (SAH). Cognitive dysfunction is the most common form of neurological impairment after an aneurysmal SAH with as many as 65% experiencing changes in cognitive functioning as a result of their aneurysmal SAH. In addition a large percentage of patients also experience changes in their daily functioning through reduced Health Related Quality of Life (HRQOL) and inability to return to work. A number of studies have focused on determining the medical causes of these changes in cognitive and HRQOL but so far no consensus have been reached. Aims: The specific aims of the present study were: 1) to explore the time-course of improvement in cognitive dysfunctions the first year after an aneurysmal SAH, 2) to investigate whether an aneurysmal SAH cause a global or focal damage, with special emphasis on the effect of Anterior Communicating Artery (ACoA) aneurysms on frontal lobe functioning, 3) to evaluate the effect of surgery of unruptured intracranial aneurysms (UIAs) compared to ruptured intracranial aneurysms on cognitive function and HRQOL, 4) to explore the cognitive functioning and HRQOL in patients in clinical condition Hunt & Hess grade V after aneurysmal SAH. Material and methods: All patients included in the studies were treated for either an aneurysmal SAH or an UIA at the Department of Neurosurgery at Rikshospitalet University Hospital from January 1st 2002 to June 30th 2007. In study I, 32 patients in clinical condition Hunt & Hess grade I-V were included. In study II, 24 patients in clinical condition Hunt & Hess grade I-III with ruptured ACoA aneurysm or 22 patients in clinical condition Hunt & Hess grade I-III with a ruptured MCA aneurysm were included. In study III, 15 patients with unruptured MCA aneurysm and 22 patients with ruptured MCA aneurysms in clinical condition Hunt & Hess grade I-III were included and finally in Study IV, 26 patients in clinical condition Hunt & Hess grad V aneurysmal SAH were included. Data was collected on medical status using CT/MR, patient journals and clinical interviews by neurosurgeons at 3 and 12 months post aneurysmal SAH/surgery for UIAs. Patients also had a clinical psychological interview. They were tested using a comprehensive neuropsychological test battery and they answered two HRQOL questionnaires (SF-36 & GHQ-30). In Study I, patients were tested neuropsychologically at 3, 6 and12 months after SAH. In Study II, patients were tested neuropsychologically at 12 months. In study III, the UIA patients were tested neuropsychologically pre-operatively, as well as 3 and 12 months post-surgery, while the aneurysmal SAH MCA patients were tested neuropsychologically 3 and 12 months post-aneurysmal SAH. Finally, in Study IV patients were tested neuropsychologically 12 months after their aneurysmal SAH. Statistical comparisons on medical, neuropsychological and HRQOL data were conducted using non-parametric statistical analysis (Mann-Whitney). In addition effect sizes were calculated using Cohens’D. Raw scores for each neuropsychological test were converted into scaled scores based on published norms for each test and then converted to z-scores for easier comparison. Results: We found mild to moderate cognitive deficits in patients in a good outcome (Glasgow Outcome Scale 4-5), with the largest deficits on motor speed and memory function, but close to normal intellectual functioning. Motor functioning seemed to improve rapidly in the first 6 months post-aneurysmal SAH while verbal memory first improved between 6 and 12 months after aneurysmal SAH. Clinical and radiological parameters reflecting the bleed and patient management could be linked to neuropsychological outcome. Our data indicated that an aneursymal SAH cause a global damage, but focal damage could be seen in some cases. For example, we suggested that ACoA patients with medial frontal damage had problems with initiation of problem solving behavior. Elective surgery of unruptured intracranial aneurysm did not cause any substantial permanent cognitive dysfunctions, but had a significant effect on the patients HRQOL. Finally, among patients in clinical condition Hunt & Hess grade V after aneurysmal SAH lower age, higher education and no hydrocephalus in the acute stages had better cognitive outcome. Conclusions: This study showed that many patients with ruptured intracranial aneurysms have cognitive deficits and problems with HRQOL as a result of their aneurysmal SAH. The cognitive deficits improved over time although not always to the pre-morbid level. The cognitive problems were most likely caused by the bleed itself rather than the treatment of the ruptured aneurysm. A focus on cognitive and HRQOL problems in the follow-up of aneurysmal SAH patients is essential and neuropsychological testing should be an integrated part of the treatment of aneurysmal SAH patients
Do all cloned animals age in the same way - telomeres and telomerase, is there any difference?
No full textIn discussions regarding modern biotechnology, cloning is the word commonly associated with this field of knowledge. This is a direct result of the world famous cloning of "Dolly" in 1997. Even though, the technology have been developed several years ago it is still in its infancy, and years might go by before good solutions are developed. What has to be noticed is that only a small percentage of cloning experiments will lead to viable offspring, and in addition, the lifespan of cloned animals seems to be shorter than their donor ancestors and sibling from normal reproduction. "Dolly's" early death led to many questions, among them; did the cloning process accelerate aging? Subsequently, many studies have been performed to find a reason for Dolly early aging. As a result, it was stated that this animal inherited shortened telomeres from the donor cell, and that was the reason for the rapid aging process. Since then many various animals have been successfully cloned. Different observations suggest that the age of the donor cell used in somatic cell nuclear transfer technique not necessarily affect the aging of cloned animals. The telomere length in animals that underwent the cloning procedure vary based on species, age, gender, cell type, culturing environment and so on. It is also important to consider genetic facts in donor animals, when telomere length seems to vary within the species. It is shown that telomere length can give an indication on cell senescence, but is not necessarily related to the aging of the organism. Different results presented in the articles imply that there is no straightforward answer when comes to early aging of cloned animals. Still there are many unanswered questions. Future research will provide us with deeper knowledge of these mechanisms, necessary for optimizing of the cloning procedure
Assessment of cerebral autoregulation dynamics from simultaneous arterial and venous transcranial Doppler recordings in humans.
No full textWe investigated the validity of transcranial Doppler recordings for the analysis of dynamic responses of cerebral autoregulation. We found no significant differences in percentage changes among maximal (centerline) blood flow velocity, cross-sectional mean blood flow velocity, and signal power-estimated blood flow during 24-mm Hg stepwise changes in arterial blood pressure. We investigated blood flow propagation delays in the cerebral circulation with simultaneous Doppler recordings from the middle cerebral artery and the straight sinus. The time for a stepwise decrease in blood flow to propagate through the cerebral circulation was only 200 msec. Brief (1.37-second) carotid artery compression tests also demonstrated that the volume compliance effects of the cerebral vascular bed were small, only about 2.2% of normal blood flow in 1 second. Furthermore, transients associated with inertial and volume compliance died out after 108 msec. We also investigated the hypothesis that autoregulatory responses are influenced by hyperventilation using the same brief carotid artery compressions. One second after release, the flow index increased by 17% during normocapnia and 36% during hypocapnia. After 5 seconds, the flow index demonstrated a clear oscillatory response during hypocapnia that was not seen during normocapnia. These results suggest that the intact human cerebral circulation in the absence of pharmacological influences does not function as predicted from pial vessel observations in animals.</jats:p
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