Will present day glacier retreat increase volcanic activity? Stress induced by recent glacier retreat and its effect on magmatism at the Vatnajokull ice cap, Iceland

Global warming causes retreat of ice caps and ice sheets. Can melting glaciers trigger increased volcanic activity? Since 1890 the largest ice cap of Iceland, Vatnajokull, with an area of similar to 8000 km(2), has been continuously retreating losing about 10% of its mass during last century. Present-day uplift around the ice cap is as high as 25 mm/yr. We evaluate interactions between ongoing glacio-isostasy and current changes to mantle melting and crustal stresses at volcanoes underneath Vatnajokull. The modeling indicates that a substantial volume of new magma, similar to 0.014 km(3)/yr, is produced under Vatnajokull in response to current ice thinning. Ice retreat also induces significant stress changes in the elastic crust that may contribute to high seismicity, unusual focal mechanisms, and unusual magma movements in NW-Vatnajokull

Perceived stress and musculoskeletal pain are prevalent and significantly associated in adolescents : An epidemiological cross-sectional study

Background: Long-term musculoskeletal pain and negative stress are health risks with adverse long-term health effects, and these health risks seem to increase among young people. The mechanisms behind this are unclear. There is a need for a better understanding of perceived stress and musculoskeletal pain among adolescents, in order to improve health promotion and treatment approaches in this group. Methods: Objectives were to evaluate the current prevalence of perceived stress and musculoskeletal pain in 15 and 16 year olds, to explore stress-pain associations and the probability that perceived stress (PSQ) was related to the reporting of pain and variations in pain, and to investigate possible differences in stress between different types of musculoskeletal pain in the adolescents. A cross-sectional study was conducted. Elementary schools participated. The outcomes were stress (Perceived stress questionnaire; PSQ) and musculoskeletal pain (pain/no pain, pain sites, pain duration and pain intensity (Visual analogue scale; VAS). Results: Fifty-one point two percent (N = 422) reported pain, of which 70.8 % reported long-term pain. Some more girls (57.9 %) reported pain. 22.0 % of the study population reported moderate to severe stress (PSQ ≥ 0.45), of which 79.6 % were bothered by pain (Pearson Chi-square 38.47, p ≤ .001). All stress and pain variables were significantly associated (p < .01). The strongest association appeared between pain intensity (VAS) and stress (PSQ) (r = 0.40). Perceived stress (PSQ) was associated with the reporting of pain among the adolescents (Odds Ratio [OR] 1.68) and could explain some of the variation in pain intensity (VAS; β = 0.15, p < .001) and number of pain sites (β = 0.14, p < .01), according to the regression analyses. There were no mean differences in stress (PSQ) between different types of musculoskeletal pain. Conclusions: There was high prevalence of musculoskeletal pain, long-term pain and moderate to severe stress (PSQ ≥ 0.45) in this study sample. Perceived stress (PSQ) was related to the reporting of musculoskeletal pain among the adolescents and could explain some of the variation in pain intensity (VAS) and number of pain sites. There were no differences in stress levels (PSQ) between different types of musculoskeletal pain in the adolescents.Open Access - This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated

Repair of distal biceps brachii tendon ruptures: long term retrospective follow-up for two-incision technique

Neðst á síðunni er hægt að nálgast greinina í heild sinni með því að smella á hlekkinn View/OpenINTRODUCTION: Rupture of the distal tendon of the biceps muscle is a rare injury. If unrepaired the patient will be left with weakness of supination of the arm and flexion in the elbow. Long term results for the 2-incision approach for tendon reinsertion are few but in this study we describe the long term, clinical, functional, and subjective results of surgical repair using the 2-incision method described by Boyd and Anderson. MATERIAL AND METHODS: All patients who were operated at FSA hospital during the years 1986-2000 because of rupture of the distal tendon of the biceps muscle were asked to participate in the study. Twelve of 16 patients accepted and answered the DASH questionnaire. Strength was tested with handheld dynamometer and ROM where measured. Radiograph was taken of the affected arm. RESULTS: From 1986 through 2006 we operated on 16 patients because of rupture of the distal biceps tendon, one female and 15 male. Mean age at the time of rupture was 46 years (24-53).The average follow up were seven years (1-17). Ten of 12 patients were operated within two weeks from the injuries. No difference in strength was found between operated and non-operated arms. Late repair was associated with high DASH score and poor subjective results. Six patients developed heterotopic ossification but none of them developed radioulnar synostosis. One reoperation because entrapment of the median nerve was done. CONCLUSIONS: Despite heterotopic ossification and a small ROM deficit the Boyd and Anderson technique for repair of distal biceps ruptures yields good long term results in a low volume rural hospital. Early diagnosis and tendon reinsertion is of great importance to avoid persistent anterior elbow pain and poor subjective results.Inngangur: Slit á fjærsin tvíhöfðavöðva upphandleggs (biceps brachi) er sjaldgæfur áverki og árangur af aðgerðum því lítt þekktur. Lýst er árangri af aðgerðum þar sem fjærsin tvíhöfðavöðva upphandleggs er endurfest með aðgerð kenndri við Boyd og Anderson. Þá eru notaðar tvær leiðir til að komast að sininni og endurfesta. Efniviður og aðferðir: Þeir sem höfðu slitið fjærsin tvíhöfðavöðva upphandleggs á árunum 1986-2006 og gengist undir aðgerð á Sjúkrahúsi Akureyrar voru beðnir að taka þátt í rannsókninni sem fólst í líkamsskoðun, hreyfiferils- og styrktarmælingum, svörun spurningalista og rö ntgenmyndatöku af olnboga og framhandlegg. Niðurstöður: Sextán manns (15 karlar, 1 kona), meðalaldur 46 ár (24-53) gengust undir aðgerð þar sem sinin var endurfest með aðferð Boyds og Andersons. Tólf sjúklingar samþykktu að taka þátt í rannsókninni, allt rétthendir karlmenn. Tíu af 12 sjúklingum gengust undir aðgerðina innan tveggja vikna frá áverkanum (0-80 dagar). Allar sinarnar greru eftir að þær voru endurfestar. Munur var ekki tölfræðilega marktækur á styrk í aðgerðararmi og þeim armi sem ekki var gerð aðgerð á. Meðal DASH-stigun var 11,7 sem telst lágt. Helmingur sjúklinga hafði merki um beinnýmyndun í mjúkvefjum. Ályktun: Þrátt fyrir beinnýmyndun í mjúkvefjum og væga hreyfiskerðingu í aðgerðararminum virðist langtímaárangur aðgerðartækni þeirra Boyds og Andersons góður. Rétt greining og aðgerð fljótlega eftir áverka virðist vera lykilatriði til þess að sjúklingum farnist vel

Post-eruptive gravity changes from 1990 to 1996 at Krafla volcano, Iceland

The 1975–1984 Krafla rifting episode was a major lava- and dyke-producing event associated with the release of extensional strain accumulated over more than 200 years at the divergent plate boundary in North Iceland. The present work provides a unique example of gravity decreases and increases sustained over a long period following a major eruptive episode at a rift volcano. After height correction, persistent net gravity decreases over the source of observed Mogi-type deflation occur with gravity increases occurring further away from this centre of deformation. Gravity decreases are interpreted in terms of drainage from a shallow magma chamber. The net gravity decreases require that at least 4×1010 kg of magma must have been drained during the 6-year observation period. Assuming a density of 2700 kg m−3, this magma would occupy 1.5×107 m3 and by analogy with results obtained for Kilauea, this implies a magma chamber volume change of 4.1×106 m3. This is consistent with the chamber volume change deduced from ground deformation data assuming a Poisson's ratio of 0.25 and a Mogi source. Net gravity increases are more spatially extensive and are most likely caused by migration of the steam–water interface and/or closure of micro-fractures in lavas above the magma chamber during post-eruptive cooling and contraction. We present a model for the Krafla magma chamber in which a cooling, contracting and draining magma body causes subsidence at the surface. These results contrast with observations from the Askja caldera, Iceland, where post-eruptive deflation has been shown to be accompanied by negligible net gravity changes above the Mogi-type source in the caldera. Long-term post-eruptive deflation and magma drainage have not been observed at subduction-related volcanoes; this may be a function of a difference in magma viscosity

Successful resuscitation of a pulseless young woman with pulmonary embolus in rural Iceland

Neðst á síðunni er hægt að nálgast greinina í heild sinni með því að smella á hlekkinn View/Open Allur texti - Full textA 27 year old woman suffered a witnessed cardiac arrest in rural Iceland and regained pulse after one hour's resuscitation. She was transported by an air ambulance to a tertiary medical center in Reykjavik where she was diagnosed with a large pulmonary embolus. After 24 hours therapeutic hypothermia she was rewarmed and extubated two days later. She was discharged from the hospital after two weeks neurologically intact. This case illustrates that even in rural circumstances the chain of survival works if all the links are strong, with early access, early resuscitation and early advanced care.27 ára kona fékk krampakippi og varð skyndilega púlslaus á Möðrudal á Fjöllum, fjarri heilbrigðisþjónustu. Eftir klukkustundar endurlífgun þreifaðist púls að nýju. Hún var flutt með sjúkraflugi á Landspítala þar sem hún var greind með stórt blóðrek í lungum. Hún var kæld í 24 klukkustundir og útskrifaðist af sjúkrahúsi á 14. degi án skerðingar á heilastarfsemi. Jafnvel við erfiðar aðstæður fjarri heilbrigðisþjónustu getur lífskeðjan reynst sterk þegar boð um aðstoð berast hratt, endurlífgun hefst án tafar og sérhæfð meðferð er veitt eins fljótt og hægt er

The effect of aerobic exercise on speed and accuracy task components in motor learning

Acute exercise has an influence on human cognition, and both theoretical approaches and previous investigations suggest that the learning process can be facilitated. A distinction has been made however, between the predominately positive effects on task speed compared to both the negative and null effects on aspects of task accuracy. The aim of this study was to investigate the effect of moderate-intensity aerobic exercise conducted before each practice trial (3 × week) for a period of four weeks, on speed and accuracy components in a novel keyboard typing task. To this end, young adults (n = 26) where randomized to a non-exercise resting group (control) or an exercise group (ergometer cycling at 65% of age-predicted maximal heart rate). Immediately after exercise or resting, participants practiced keyboard typing through specialized online software for a total of 2 h across the study period. All participants improved their speed and accuracy in the keyboard typing task. At 7-day retention, no differences were found between groups. Thus, the degree of improvement on both speed and accuracy task components was not significantly different between the exercise and control group. Further studies are warranted to establish the specific relationship between aerobic exercise and task components in motor learning and retention.publishedVersio

Performance of a revised capnodynamic method for cardiac output monitoring

Cardiac output (CO) monitoring is ideal for guiding fluid, vasopressor and inotropic therapy for sufficient oxygen delivery and may improve outcome in high risk surgery. In this context, many minimally-and non-invasive methods have emerged during recent years, however, they appear less reliable when compared to the thermodilution methods during rapid changes in vascular volume and resistance, a common feature during major surgery. The capnodynamic method calculates non-shunted cardiac output, the effective pulmonary blood flow (COEPBF), on the basis of a capnodynamic equation describing the mole balance of CO2 transported to and from the lungs. By prolonging three out of every nine breaths in mechanically ventilated patients, COEPBF is automatically and continuously calculated with each new breath. In previous studies the capnodynamic method with inspiratory holds provided CO mon-itoring, however with unacceptable accuracy and precision during lung injury and elevated positive end-expiratory pressure (PEEP). In this thesis we evaluated the revised capnodynamic method with expiratory holds in four separate studies. In a large animal model (study I-III), COEPBF was compared to a gold stan-dard flowmeter placed around the pulmonary trunk during different hemodynamic, ventila-tory, respiratory and metabolic challenges. Finally, COEPBF was compared to transpulmonary thermodilution in patients undergoing high risk abdominal cancer surgery. The capnodynamic method showed overall acceptable agreement and good trending abil-ities in a variety of conditions familiar to a perioperative team. The agreement was tempo-rarily disrupted after ischemia-reperfusion, however reestablished within five minutes. The accuracy was marginally affected during lung injury, both at high shunt fractions and after recruitment manoeuvre with PEEP adjustment. However, both precision and trending ability were maintained. In high risk patients, COEPBF showed good accuracy, acceptable precision and good trending ability in various conditions. The performance was especially robust after individualized lung recruitment and PEEP adjustment. COEPBF may provide continuous CO monitoring with short response time, good trending abilities and acceptable agreement to guide hemodynamic treatment during surgery

Lens magnification by CL0024+1654 in the U and R band

[ABRIDGED] We estimate the total mass distribution of the galaxy cluster CL0024+1654 from the measured source depletion due to lens magnification in the R band. Within a radius of 0.54Mpc/h, a total projected mass of (8.1+/-3.2)*10^14 M_sol/h (EdS) is measured, which corresponds to a mass- to-light ratio of M/L(B)=470+/-180. We compute the luminosity function of CL0024+1654 in order to estimate contamination of the background source counts from cluster galaxies. Three different magnification-based reconstruction methods are employed using both local and non-local techniques. We have modified the standard single power-law slope number count theory to incorporate a break and applied this to our observations. Fitting analytical magnification profiles of different cluster models to the observed number counts, we find that the cluster is best described either by a NFW model with scale radius r_s=334+/-191 kpc/h and normalisation kappa_s=0.23+/-0.08 or a power-law profile with slope xi=0.61+/-0.11, central surface mass density kappa_0=1.52+/-0.20 and assuming a core radius of r_core=35 kpc/h. The NFW model predicts that the cumulative projected mass contained within a radius R scales as M(<R)=2.9*10^14*(R/1')^[1.3-0.5lg (R/1')] M_sol/h. Finally, we have exploited the fact that flux magnification effectively enables us to probe deeper than the physical limiting magnitude of our observations in searching for a change of slope in the U band number counts. We rule out both a total flattening of the counts with a break up to U_AB<=26.6 and a change of slope, reported by some studies, from dlog N/dm=0.4->0.15 up to U_AB<=26.4 with 95% confidence.Comment: 19 pages, 12 figures, submitted to A&A. New version includes more robust U band break analysis and contamination estimates, plus new plot

Self-Efficacy, Flow, Affect, Worry and Performance in Elite World Cup Ski Jumping

The present study investigated the relationship between self-efficacy, flow, positive- and negative affect, worry and ski jumping performance, as well as the degree of influence these psychological factors have on ski jumping performance in specific competitions and overall World Cup ranking. World Cup ski jumpers (N = 40) responded to four questionnaires in the middle of the World Cup season, reporting their subjective experience during a competitive setting over a period of three consecutive days. Social Cognitive Theory (SCT) and Flow Theory was used as main conceptual frameworks. Self-efficacy was moderately related to ski jumping performance, both overall World Cup ranking (r = −0.37) and the results from the first out of three individual ski flying competitions (r = −0.36) and explained approximately 14% of the variance in the overall World Cup. Flow was moderately related to ski jumping performance, both overall World Cup ranking (Flow-Focus) (r = −0.34), and individual ski flying results from the first competition (Flow-Arousal) (r = −0.36). The Flow-Arousal explained approximately 13% of the variance in ski flying results. Worry was highly related to ski jumping performance in the second (r = 0.60) and third (r = 0.52) competition, indicating that approximately 36 and 27% of the variance in ski flying results could be accounted for by levels of worry, respectively. Negative affect was moderately related to ski flying performance (r = 0.34). These results show that psychological factors that regulate emotional states may be of importance for World Cup ski jumping performance, and that appropriate coping strategies, constructive mindset and motivation, appears to be essential in this regard. To our knowledge, this is the first study on the relationship between these psychological factors and ski jumping performance among World Cup athletes. The study adds important information about some of the dynamic features of emotional and psychological mechanisms involved during elite ski jumping performance