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The purpose of this paper is to study whether Swedish admission policies successful in selecting the best-performing students. The Swedish universities select students based on two different instruments, which each form a separate admission group. A regression model is recommended to estimate the achievement differences for the marginally accepted students between the admission groups and is applied to a sample of 9024 Swedish university entrants in four different fields of education. Marginally accepted students in the group selected by school grades on average perform better than students accepted by an admission test, suggesting that a small reallocation of study positions towards the grade admission group may increase overall academic achievement. However, the achievement difference appears to vary concerning university programme selectivity. We found that increasing selection by grades in less competitive programmes would improve overall achievement, while we do not find any effect for highly competitive programmes.

This paper analyses the associations between computer use in schools and at home and test scores by using TIMSS data covering over 900,000 children in fourth grade. When controlling for school fixed effects, pupils who use computers at school, especially those who use them frequently are found to achieve less than students who never use computers. Daily computer use at home is negatively associated with test scores, although monthly, and sometimes weekly, use is positively associated with pupil performance. There is no significant difference between subjects and only small gender and country differences are observed. Moreover, the result suggests that the negative association of computer use at school is larger among low-performing pupils than for high-performing pupils. The findings suggest a negative association of computer use at school and test scores but do not reject the possibility that computers have a positive impact on test scores if computers are used optimally. Funding: Handelsbanken (P2016-0299).

The susceptibility of cloud droplet number concentration (CDNC) to cloud condensation nuclei (CCN) number concentration is one of the major factors controlling the aerosol indirect forcing. In this study we investigate the sensitivity of CDNC to CCN concentrations using long term in-situ observations from three stations (Puijo, Pallas, Zeppelin) locating in Finland and Arctic. These stations represent semiurban, remote and Arctic remote environments with differences in typical updraft velocity conditions as well as in aerosol number concentrations. We compare the in-situ observations with three large scale models (ECHAM-M7, ECHAM-SALSA and NorESM) having differences in aerosol presentation while the activation parametrization is the same in all three model setups. In the comparison we use CDNC and CCN model outputs of the gridbox corresponding to the location and the height for each station. In addition, we compare the updraft velocities from the models and stations when they are available. Our current observational results show very high susceptibility of CDNC and CCN in all investigated stations. The agreement between the large scale models and observations was very good for Puijo and Pallas stations, but for the Arctic station (Zeppelin) the modelled CDNC susceptibility to CCN was much lower than the observed. This might be related to the recent results demonstrating that Aitken mode particles can active to cloud droplets at Zeppelin station (Bulatovic et al., 2021; Karlsson et al., 2021). In addition, at Zeppelin CDNC exhibits very low values which are below the lower bound imposed by ECHAM.References:Bulatovic, I., Igel, A. L., Leck, C., Heintzenberg, J., Riipinen, I., and Ekman, A. M. L.: The importance of Aitken mode aerosol particles for cloud sustenance in the summertime high Arctic – a simulation study supported by observational data, Atmos. Chem. Phys., 21, 3871–3897, https://doi.org/10.5194/acp-21-3871-2021, 2021.Karlsson, L., Krejci, R., Koike, M., Ebell, K., and Zieger, P.: A long-term study of cloud residuals from low-level Arctic clouds, Atmos. Chem. Phys., 21, 8933–8959, 2021.

The amount of ice versus supercooled water in clouds is important for their radiative properties and role in climate feedbacks. Hence, knowledge of the concentration of ice-nucleating particles (INPs) is needed. Generally, the concentrations of INPs are found to be very low in remote marine locations allowing cloud water to persist in a supercooled state. We had expected the concentrations of INPs at the North Pole to be very low given the distance from open ocean and terrestrial sources coupled with effective wet scavenging processes. Here we show that during summer 2018 (August and September) high concentrations of biological INPs (active at >−20°C) were sporadically present at the North Pole. In fact, INP concentrations were sometimes as high as those recorded at mid-latitude locations strongly impacted by highly active biological INPs, in strong contrast to the Southern Ocean. Furthermore, using a balloon borne sampler we demonstrated that INP concentrations were often different at the surface versus higher in the boundary layer where clouds form. Back trajectory analysis suggests strong sources of INPs near the Russian coast, possibly associated with wind-driven sea spray production, whereas the pack ice, open leads, and the marginal ice zone were not sources of highly active INPs. These findings suggest that primary ice production, and therefore Arctic climate, is sensitive to transport from locations such as the Russian coast that are already experiencing marked climate change., Journal of Geophysical Research: Atmospheres, 127 (6), ISSN:0148-0227, ISSN:2169-897X

The physical and chemical properties of aerosol particles are important for the formation of cloud droplets and ice crystals. This is especially true for pristine regions such as the Arctic, where particle number concentrations are often very low. Observations from these regions are still sparse due to the technical challenges involved.Here, we present recent results of detailed in-situ observations of aerosols and clouds performed on board the Swedish icebreaker Oden over the central Arctic Ocean in 2018. We show that Aitken-mode particles, i.e. particles below 70 nm diameter, contribute significantly to cloud-forming particles (here termed cloud residuals), especially towards autumn with the start of the freeze-up of the sea ice. These cloud-forming Aitken-mode particles coincided with air that spent more time over the ice, while accumulation-mode dominated cloud residuals showed more of an oceanic influence, as shown using air back trajectory analysis. At the same time, the Aitken-mode dominated cloud residuals were associated with changes in the average chemical composition of the accumulation mode showing an increased organic contribution, in contrast to the accumulation-mode dominated cloud residuals, which showed an increased sulfate contribution. The Hoppel-minima in both whole-air and cloud residual size distributions was almost unchanged, suggesting only little addition of aerosol mass due to aqueous-phase cloud processing. Our highly detailed observations of aerosol-cloud interactions over the central Arctic Ocean close to the North Pole provide valuable insights into the properties and the origin of particles that are relevant for cloud formation in this remote region of our planet.This work is currently in review at the Journal of Geophysical Research (JGR).

Predictions of cloud droplet activation in the late summertime (September) central Arctic Ocean are made using κ-Köhler theory with novel observations of the aerosol chemical composition from a high-resolution time-of-flight chemical ionization mass spectrometer with a filter inlet for gases and aerosols (FIGAERO-CIMS) and an aerosol mass spectrometer (AMS), deployed during the Arctic Ocean 2018 expedition onboard the Swedish icebreaker Oden. We find that the hygroscopicity parameter κ of the total aerosol is 0.39 ± 0.19 (mean ± std). The predicted activation diameter of ∼25 to 130 nm particles is overestimated by 5%, leading to an underestimation of the cloud condensation nuclei (CCN) number concentration by 4–8%. From this, we conclude that the aerosol in the High Arctic late summer is acidic and therefore highly cloud active, with a substantial CCN contribution from Aitken mode particles. Variability in the predicted activation diameter is addressed mainly as a result of uncertainties in the aerosol size distribution measurements. The organic κ was on average 0.13, close to the commonly assumed κ of 0.1, and therefore did not significantly influence the predictions. These conclusions are supported by laboratory experiments of the activation potential of seven organic compounds selected as representative of the measured aerosol.

The amount of ice versus supercooled water in clouds is important for their radiative properties and role in climate feedbacks. Hence, knowledge of the concentration of ice-nucleating particles (INPs) is needed. Generally, the concentrations of INPs are found to be very low in remote marine locations allowing cloud water to persist in a supercooled state. We had expected the concentrations of INPs at the North Pole to be very low given the distance from open ocean and terrestrial sources coupled with effective wet scavenging processes. Here we show that during summer 2018 (August and September) high concentrations of biological INPs (active at >−20°C) were sporadically present at the North Pole. In fact, INP concentrations were sometimes as high as those recorded at mid-latitude locations strongly impacted by highly active biological INPs, in strong contrast to the Southern Ocean. Furthermore, using a balloon borne sampler we demonstrated that INP concentrations were often different at the surface versus higher in the boundary layer where clouds form. Back trajectory analysis suggests strong sources of INPs near the Russian coast, possibly associated with wind-driven sea spray production, whereas the pack ice, open leads, and the marginal ice zone were not sources of highly active INPs. These findings suggest that primary ice production, and therefore Arctic climate, is sensitive to transport from locations such as the Russian coast that are already experiencing marked climate change.

The summertime high Arctic is an extremely low-aerosol region, where even small inputs of particles can have significant impacts on cloud formation and therefore on the surface energy budget. The relative importance of new particle formation from gas phase precursors and primary sea spray production in this region remains uncertain, as does the role of atmospheric transport. We made direct, time-resolved composition measurements of Aitken mode (~20-60 nm diameter) aerosol over the high Arctic pack ice in August-September 2018, including during an intense Aitken mode formation event on August 30-31. The event particles contained both primary sea spray materials (sodium, potassium, and polysaccharide-like organics) and secondary components (non-sea-salt sulfate, methanesulfonic acid, non-sea-salt iodine, and secondary organics), most of which could be quantified on the basis of analytical standards. The composition is consistent with primary sea spray that had been atmospherically processed, and the aerosol size distribution dynamics imply the action of a process by which larger atmospheric particles or aggregates broke up to form smaller particles. Hypotheses to explain the results will be discussed.

11 pags., 4 figs., New particle formation in the Arctic atmosphere is an important source of aerosol particles. Understanding the processes of Arctic secondary aerosol formation is crucial due to their significant impact on cloud properties and therefore Arctic amplification. We observed the molecular formation of new particles from low-volatility vapors at two Arctic sites with differing surroundings. In Svalbard, sulfuric acid (SA) and methane sulfonic acid (MSA) contribute to the formation of secondary aerosol and to some extent to cloud condensation nuclei (CCN). This occurs via ion-induced nucleation of SA and NH and subsequent growth by mainly SA and MSA condensation during springtime and highly oxygenated organic molecules during summertime. By contrast, in an ice-covered region around Villum, we observed new particle formation driven by iodic acid but its concentration was insufficient to grow nucleated particles to CCN sizes. Our results provide new insight about sources and precursors of Arctic secondary aerosol particles., The authors acknowledge European Research Council (GASPARCON, Grant no. 714621 and COALA, Grant no. 638703), Academy of Finland (Project nos. 296628, 306853, 317380, 316114, and 320094), INTERACT, European Regional Development Fund (project MOBTT42), Austrian Science Fund (FWF, Project J3951-N36), the European Union's Horizon 2020 Research and Innovation Program (Grant no. 689443) via project iCUPE (Integrative and Comprehensive Understanding on Polar Environments) and Project ERC-2016- COG 726349 CLIMAHAL, National Research Foundation (NRF) of the Ministry of Science, ICT and Future Planning (NRF-2018R1A2A1A19019281), Knut-and-Alice-Wallenberg Foundation within the Arctic Climate Across Scales (Project No. \,2016.0024), the Swedish EPA's (Naturvårdsverket) Environmental monitoring program (Miljöövervakning), the Swedish Research Council FORMAS (Project "Interplay between water, clouds and Aerosols in the Arctic," \# 2016-01427), Climate Change Tower – Integrated Project of the National Research Council of Italy and the National Interest Project by the Italian Minister of Education, University and Research (PRIN2007 and PRIN2009). The authors thank Department of Earth System Sciences and Technologies for the Environment, Department of Earth Sciences and Technology of the Environment of CNR and the doctoral program in atmospheric sciences at the University of Helsinki for financial support. Aarhus University acknowledge financial support from Danish Ministry of Environment and food and Ministry of Climate, Energy and Utilities by means of DANCEA.

To constrain uncertainties in radiative forcings associated with aerosol--cloud interactions, improved understanding of Arctic cloud formation is required, yet long-term measurements of the relevant cloud and aerosol properties remain sparse. We present the first long-term study of cloud residuals, i.e. particles that were involved in cloud formation, and ambient aerosol particles in Arctic low-level clouds measured at Zeppelin Observatory, Svalbard. A detailed evaluation of the ground-based counter-flow virtual impactor inlet system is also presented. Cloud residuals as small as 15 nm are routinely observed especially during the dark period and are potentially linked to ice, supporting prior work suggesting that classical droplet activation is not the only relevant process in the formation of Arctic low-level clouds. The reported measurements and findings provide a new basis for improving our understanding of Arctic clouds and for developing robust parameterisations of mixed-phase clouds in Earth system models.

11 pags., 4 figs.-- Correction: https://www.nature.com/articles/s41467-020-19533-y, In the central Arctic Ocean the formation of clouds and their properties are sensitive to the availability of cloud condensation nuclei (CCN). The vapors responsible for new particle formation (NPF), potentially leading to CCN, have remained unidentified since the first aerosol measurements in 1991. Here, we report that all the observed NPF events from the Arctic Ocean 2018 expedition are driven by iodic acid with little contribution from sulfuric acid. Iodic acid largely explains the growth of ultrafine particles (UFP) in most events. The iodic acid concentration increases significantly from summer towards autumn, possibly linked to the ocean freeze-up and a seasonal rise in ozone. This leads to a one order of magnitude higher UFP concentration in autumn. Measurements of cloud residuals suggest that particles smaller than 30 nm in diameter can activate as CCN. Therefore, iodine NPF has the potential to influence cloud properties over the Arctic Ocean., The Swedish Polar Research Secretariat (SPRS) provided access to the I/B Oden and logistical support in collaboration with the U.S. National Science Foundation. This work was supported by the Swiss National Science Foundation (grant no. 200021_169090), the Swiss Polar Institute, the BNP Paribas Swiss Foundation (Polar Access Fund 2018), the Knut-and Alice-Wallenberg Foundation within the ACAS project (Arctic Climate Across Scales, project no. 2016.0024), the Bolin Centre for Climate Research (RA2), the Swedish Research Council (project nos. 2018-05045 and 2016-05100) and by the Natural Environment Research Council (grant no. NE/R009686/1). J.S. holds the Ingvar Kamprad Chair, sponsored by Ferring Pharmaceuticals. A.S.-L. acknowledges the funding from the European Research Council Executive Agency under the European Union’s Horizon 2020 Research and Innovation program (Project ‘ERC-2016-COG 726349 CLIMAHAL’). Funding of the expedition AO2018 was provided to Caroline Leck by the NSF and SPRS’s Cost sharing Understanding Arctic Ocean 2018 Reg. no. 2018-113, and by the Swedish Research Council projects nos. 824-2013-222 and 2016-03518. We are grateful to Xu-Cheng He (University of Helsinki, Finland) for the insightful discussions about iodine NPF and for helping with the calibration of the nitrate CIMS. We would like to thank Michael Wheeler and Richard Leaitch (Environment and Climate Change Canada) for lending the CVI inlet and the technical support and Silvia Henning (TROPOS, Germany) for lending and calibrating the cloud condensation nuclei counter. We also thank Heini Wernli (ETH Zürich, Switzerland) for calculating the air mass backtrajectories, Barbara Brooks (National Centre for Atmospheric Science, U.K.) for processing the FSSP data and John Prytherch (Stockholm University, Sweden) for processing temperature and wind speed data. We acknowledge the CABM network for providing the iodine measurement at Alert and CFS Alert for maintaining infrastructure for Alert location.

Abstract The study of a freezing droplet is interesting in areas, where the understanding of build up of ice is important, for example, on wind turbines, airplane wings and roads. In this work, the main focus is to study the internal motion inside freezing water droplets using particle image velocimetry and to reveal if mechanisms such as natural convection and Marangoni convection have a noticeable influence on the flow within the droplet. The flow has successfully been visualized and measured for the first 25% of the total freezing time of the droplet when the velocity in the water is the highest and when the characteristic vortices can be seen. After this initial time period, the high amount of ice in the droplet scatters the PIV light sheet too much and the images retrieved are not suitable for analysis. Initially, it can be seen that the Marangoni effects have a large impact on the internal flow, but after about 15% of the total freezing time, the flow turns indicating increased effects of natural convection on the flow. Shortly after this time, almost no internal flow can be seen. Graphic abstract

The flow within freezing water droplets is here numerically modelled assuming fixed shape throughout freezing. Three droplets are studied with equal volume but different contact angles and two cases are considered, one including internal natural convection and one where it is excluded, i.e. a case where the effects of density differences is not considered. The shape of the freezing front is similar to experimental observations in the literature and the freezing time is well predicted for colder substrate temperatures. The latter is found to be clearly dependent on the plate temperature and contact angle. Including density differences has only a minor influence on the freezing time, but it has a considerable effect on the dynamics of the internal flow. To exemplify, in the vicinity of the density maximum for water (4 ∘C) the velocities are about 100 times higher when internal natural convection is considered for as compared to when it is not.

Purpose The purpose of this study was to describe how patients with chronic pain experience physical activity and exercise (PA&E). Method This qualitative interview study included 16 women and two men suffering from chronic pain and referred to a multimodal pain rehabilitation program. Semi-structured interviews were conducted and qualitative content analysis was used to analyze the interviews. Results One main theme emerged: “To overcome obstacles and to seize opportunities to be physically active despite chronic pain.” This main theme was abstracted from five themes: “Valuing a life with physical activity,” “Physical activity and exercise – before and after pain,” “A struggle – difficulties and challenges,” “The enabling of physical activity,” and “In need of continuous and active support.” Conclusion Although these participants valued PA&E, they seldom achieved desirable levels, and performance of PA&E was undermined by difficulties and failure. The discrepancy between the intention to perform physical activity and the physical activity accomplished could be related to motivation, self-efficacy, and action control. The participants desired high-quality interaction with healthcare providers. The findings can be applied to chronic pain rehabilitation that uses PA&E as treatment.

BackgroundIn peripheral tissue, several substances influence pain and pain modulation. Exercise has been found to decrease pain and improve function for chronic pain conditions, but how and why exe ...

Chronic pain is common in western countries and entails considerable consequences for the afflicted individuals as well as for the society. Furthermore, chronic pain is complex including an advanced interplay between biological-, psychological- and social aspects. Treatment of chronic pain attempts to decrease pain intensity and increase physical-, psychological- and social functioning. However, the treatment of chronic pain is still not optimized. Different types of physical activity and exercise (PA&E) are commonly applied as non-pharmacological treatment strategies for chronic pain, but the most efficient type and dose of PA&E are unclear. In addition, adherence to prescribed PA&E is often troublesome, which further complicates the application of PA&E as treatment for chronic pain. The aim of this thesis is to increase the knowledge about PA&E as treatment for chronic pain regarding pain intensity, biochemical substances, adherence and attitudes. The findings of this thesis were that a long-term, home-based PA&E intervention comprising strength exercises as well as stretch exercises decreased pain intensity and increased function in women with chronic neck- and shoulder pain. Using microdialysis technique, differences in pain modulatory biochemical substances were found, before the intervention, in painful trapezius muscle compared to pain-free trapezius muscle. In addition, alterations in pain modulatory substances in painful trapezius muscle after the intervention were found, which possibly could imply peripheral physiological effects of PA&E. Furthermore, psychological factors could be associated to the effects of and adherence to the PA&E intervention. An intention to be physically active were expressed by patients with chronic pain, but a discordance between the intention and PA&E-behaviour were evident, even though the PA&E were experienced as valuable. In conclusion, this thesis strengthens the importance of PA&E as treatment for chronic pain. Especially, this thesis increases the knowledge about; possible peripheral pain inhibitory effects after long-term exercise; how psychological factors might affect the results of PA&E; and also about important behavioural aspects that might affect adherence to prescribed PA&E. This thesis highlights the need of more research on physiological pain inhibitory effects of long-term PA&E in chronic pain. Furthermore, improved methods for ensured adherence to prescribed PA&E are necessary in order to optimize the effect of PA&E as treatment for chronic pain.

Chronic widespread pain (CWP), including fibromyalgia syndrome (FM), is associated with prominent negative consequences. CWP has been associated with alterations in the central processing of nociception. Whereas some researchers consider CWP/FM as a central hyperexcitability pain condition, others suggest that the central alterations are maintained by peripheral nociceptive input. Microdialysis can be used in vivo to study muscle alterations in chronic myalgia.: The aim of the study was to investigate the plasma and interstitial concentrations of metabolites and algesics in the trapezius muscle of women with CWP and in pain-free women (CON).Seventeen women with CWP and 24 CON went through a clinical examination and completed a questionnaire; the pressure pain thresholds in the upper and lower extremities were registered. Microdialysis was conducted in the trapezius muscle, and a blood sample was drawn. Muscle blood flow, interstitial muscle concentrations, and plasma concentrations of lactate, pyruvate, glutamate, glucose, and glycerol (not in the plasma) were determined.CWP patients had significantly increased interstitial muscle (P=0.02 to 0.001) and plasma (P=0.026 to 0.017) concentrations of lactate and glutamate. No significant differences existed in blood flow between CWP and CON. The interstitial concentrations-but not the plasma levels-of glutamate and lactate correlated significantly with aspects of pain such as pressure pain thresholds of the trapezius (R=0.22) and tibialis anterior (R=0.18) and the mean pain intensity (R=0.10) in CWP but not in CON.The present study supports the suggestion that aspects of pain and central alterations in CWP/FM are influenced by peripheral tissue alterations.

To describe what patients with chronic pain expect from a multimodal pain rehabilitation programme.Qualitative interviews were used to uncover expectations about a multimodal rehabilitation programme offered at the Pain and Rehabilitations Centre, The University Hospital; Linköping, Sweden. Sixteen women and two men (mean age 37 years; standard deviation 10 years) with chronic benign pain participated. The interviews were analysed using qualitative content analyses.To participate actively in the multimodal pain rehabilitation programme and to learn adequate coping strategies to improve daily life emerged as a main category. It was based on the following four categories comprising expectations about: participating actively in the programme, interacting with the professionals and fellow patients, cognitive effects of the programme and tools for coping, and explicit effects from the programme.Many patients expressed expectations which may reflect that the information before the programme had started rehabilitation process at the time point for this study. The results could be applied in rehabilitation programmes by acknowledging expectations to interact with professional team members and fellow patients, by early addressing of positive and negative expectations about the future pain and by incorporating and strengthen expectations of learning to cope with pain. Implications for Rehabilitation Patients' expectations to interact with professional team members and fellow patients by participating actively in the pain rehabilitation programme should be acknowledged in each rehabilitation situation. Patients expressed both positive and negative expectations about their future pain situation and these expectations should be addressed as early as possible in the rehabilitation screening process. Patients' expectations of learning to cope with pain should be incorporated and strengthened in multimodal pain rehabilitation programmes.

The microdialysis technique is a method for sampling endogenous molecules from the interstitial compartments of varying tissues and relies on diffusion of molecules between the tissue and a perfusate via a membrane. Such samples do not allow determination of the true interstitial concentration but only a certain percentage. This gives rise to one of the most crucial parameter that needs to be considered for a dependable microdialysis; the relative recovery. Relative recovery states the efficiency of which an analyte is extracted from its external medium. Aim. To investigate the relative recovery of small molecules (20 kDa) such as lactate, fluid recovery and the reproducibility of the relative recovery at group and individual level of the microdialysis technique applied in muscle.Using in vivo microdialysis of the trapezius muscle of 65 women from two separate occasions 4-6 months apart. Relative recovery of small molecules was measured from samples collected every 20 min during a period of 220 min.Good reproducibility at group level of catheters with cut-offs 100 and 20kDa were found. Furthermore, there was a high and steady relative recovery with an overall good fluid recovery. Poor reproducibility was found at the individual level for both catheters.This study demonstrates that when using microdialysis in skeletal muscle relative recovery is stable over time and is not affected by low-force exercise. Although there is a good reproducibility at group level this is not the case at the individual level. Thus in vivo, the relative recovery should be determined for each test subject and at each test occasion.

U-Pb baddeleyite geochronology and geochemistry of mafic cobbles from the similar to 300 Ma Dwyka diamictite on the western boundary of the Kalahari Basin provide new insights into the sub-Kalahari basement. Palaeo-ice flow directions indicate that the origin of the Dwyka diamictite deposits on the border between South Africa and Namibia is from beneath the Kalahari sands to the east or north-east. This work shows that the mafic cobbles from three localities near Rietfontein come from intrusions related to the Umkondo Large Igneous Province (LIP), located in the Kheis or Rehoboth Provinces. The lack of Banded Iron Formation (BIF) cobbles in these glacial diamictites indicates that their source region lies west or north of the BIF-dominated Griqualand West Basin of the Kaapvaal Craton. The four dated mafic cobbles give U-Pb ages of 1111-1123 Ma, coeval with dolerites of the Umkondo LIP. The cobbles experienced greenschist fades metamorphism before the Dwyka glaciation, but are unfoliated. The geochemistry of the cobbles indicates that they are genetically similar and have a within-plate setting. They show many similarities to the Umkondo LIP dolerites and the coeval Rouxville Formation, an upper unit of the Koras Group. The most likely sources of the cobbles are the mafic intrusives and lavas along the Kalahari Line, southern equivalents of the similar to 1.11 Ga Tshane and Xade complexes or intrusive and extrusive mafic units related to the Umkondo LIP, now concealed beneath the Kalahari sands. (C) 2011 Elsevier By. All rights reserved.

Godkänd; 2014; 20140923 (andbra)

Background Different types of exercises can help manage chronic neck pain. Supervised exercise interventions are widely used, but these protocols require substantial resources. The aim of this trial, which focused on adherence, was to evaluate two home exercise interventions. Methods This parallel group randomized controlled trial included 57 women randomly allocated into two groups – a strength training group (STRENGTH, 34 subjects) and a stretching group (STRETCH, 23 subjects). The interventions focused on the neck and shoulder muscles and lasted for 12 months. The STRENGTH group performed weight training and ended each session with stretching exercises. These stretching exercises constituted the entirety of the STRETCH group’s training session. Both groups were instructed to exercise three times per week. All the participants kept an exercise diary. In addition, all participants were offered support via phone and e-mail. The primary outcomes were pain intensity and function. The trial included a four- to six-month and a twelve-month follow-up. A completer in this study exercised at least 1,5 times per week during eight unbroken weeks. A responder in this study reported clinically significant improvements on pain and function. The statistical analyses used the Mann Whitney U-test, Wilcoxon signed-rank test, and X 2 test. Results At four- to six-months, the numbers of completers were 19 in the STRENGTH group and 17 in the STRETCH group. At twelve months, the corresponding numbers were 11 (STRENGTH) and 10 (STRETCH). At four- to six-months, the proportions of subjects reporting clinically important changes (STRENGTH and STRETCH) were for neck pain: 47% and 41%, shoulder pain: 47% and 47%, function: 37% and 29%. At twelve months, the corresponding numbers were for neck pain: 45% and 40%, shoulder pain: 55% and 50%, function: 55% and 20%. Conclusions No differences in the two primary outcomes between the two interventions were found, a finding that may be due to the insufficient statistical power of the study. Both interventions based on home exercises improved the two primary outcomes, but the adherences were relatively low. Future studies should investigate ways to improve adherence to home exercise treatments. Trial registration ClinicalTrials.gov Id: NCT01876680

BACKGROUND: N-acylethanolamines (NAEs) are endogenous compounds that regulate inflammation and pain. These include the cannabinoid ligand anandamide (AEA) and the peroxisome proliferator-activated receptor-α ligand palmitoylethanolamide (PEA). Little is known as to the levels of NAEs in pain states in human, particularly in the skeletal muscle. The aim of this study was to investigate the levels of these lipid mediators in muscle dialysate from women with chronic neck-/shoulder pain compared to healthy controls. METHODS: Eleven women with chronic neck-/shoulder pain and eleven healthy women participated in this study. All participants went through microdialysis procedures in the trapezius muscle. Muscle dialysate samples were collected during four hours and analysed by nano liquid chromatography tandem mass spectrometry (nLC-MS/MS). RESULTS: We were able to detect AEA, PEA, N-stearoylethanolamine (SEA) and 2-arachidonoylglycerol (2-AG) in a single chromatographic run. Of the NAEs studied, PEA and SEA were clearly detectable in the muscle microdialysate samples. The muscle dialysate levels of PEA and SEA were significantly higher in myalgic subjects compared to healthy controls. CONCLUSION: This study demonstrates that microdialysis in combination with mass spectrometry can be used for analysing NAE's in human muscle tissue regularly over time. Furthermore the significant group differences in the concentration of PEA and SEA in this study might fill an important gap in our knowledge of mechanisms in chronic myalgia in humans. In the long run this expanded understanding of nociceptive and anitinociceptive processes in the muscle may provide a base for ameliorating treatment and rehabilitation of pain.

Detailed knowledge of the physical and chemical properties and sources of particles that form clouds is especially important in pristine areas like the Arctic, where particle concentrations are often low and observations are sparse. Here, we present in situ cloud and aerosol measurements from the central Arctic Ocean in August-September 2018 combined with air parcel source analysis. We provide direct experimental evidence that Aitken mode particles (particles with diameters less than or similar to 70 nm) significantly contribute to cloud condensation nuclei (CCN) or cloud droplet residuals, especially after the freeze-up of the sea ice in the transition toward fall. These Aitken mode particles were associated with air that spent more time over the pack ice, while size distributions dominated by accumulation mode particles (particles with diameters greater than or similar to 70 nm) showed a stronger contribution of oceanic air and slightly different source regions. This was accompanied by changes in the average chemical composition of the accumulation mode aerosol with an increased relative contribution of organic material toward fall. Addition of aerosol mass due to aqueous-phase chemistry during in-cloud processing was probably small over the pack ice given the fact that we observed very similar particle size distributions in both the whole-air and cloud droplet residual data. These aerosol-cloud interaction observations provide valuable insight into the origin and physical and chemical properties of CCN over the pristine central Arctic Ocean., Journal of Geophysical Research: Atmospheres, 127 (11), ISSN:0148-0227, ISSN:2169-897X

The remote central Arctic during summertime has a pristine atmosphere with very low aerosol particle concentrations. As the region becomes increasingly ice-free during summer, enhanced ocean-atmosphere fluxes of aerosol particles and precursor gases may therefore have impacts on the climate. However, large knowledge gaps remain regarding the sources and physicochemical properties of aerosols in this region. Here, we present insights into the molecular composition of semi-volatile aerosol components collected in September 2018 during the MOCCHA (Microbiology-Ocean-Cloud-Coupling in the High Arctic) campaign as part of the Arctic Ocean 2018 expedition with the Swedish Icebreaker Oden. Analysis was performed offline in the laboratory using an iodide High Resolution Time-of-Flight Chemical Ionization Mass Spectrometer with a Filter Inlet for Gases and AEROsols (FIGAERO-HRToF-CIMS). Our analysis revealed significant signal from organic and sulfur-containing compounds, indicative of marine aerosol sources, with a wide range of carbon numbers and O : C ratios. Several of the sulfur-containing compounds are oxidation products of dimethyl sulfide (DMS), a gas released by phytoplankton and ice algae. Comparison of the time series of particulate and gas-phase DMS oxidation products did not reveal a significant correlation, indicative of the different lifetimes of precursor and oxidation products in the different phases. This is the first time the FIGAERO-HRToF-CIMS was used to investigate the composition of aerosols in the central Arctic. The detailed information on the molecular composition of Arctic aerosols presented here can be used for the assessment of aerosol solubility and volatility, which is relevant for understanding aerosol–cloud interactions., Molecular-level analysis of High Arctic aerosols sampled on a cruise to the North Pole shows: (1) a wide range of semi-volatile organic compounds, (2) no clear relationship between DMS oxidation products in the gas- and particle-phase