| 1. |
- Hanstock, Helen, 1989-, et al.
(författare)
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A heat-and-moisture exchanging mask may increase the physiological demands of submaximal exercise in -15 degrees Celsius.
- 2020
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Ingår i: Book of Abstracts of the 25th Annual Congress of the European College of Sport Science – 28th - 30th October 2020. - 9783981841435 ; , s. 75-76
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Konferensbidrag (refereegranskat)abstract
- INTRODUCTION: Winter endurance athletes such as cross-country skiers have an increased prevalence of asthma (Eriksson et al., 2018, Scand J Med Sci Sport). Heat-and-moisture exchangers (HMEs) such as masks and mouthpieces with a filter to facilitate warming and humidification of inspired air may protect the airways from injury during exercise in cold, dry climates. However, if there is evidence of impaired exercise capacity, athletes will likely avoid using such devices. The aim of this study was to investigate the influence of an HME mask (AirTrim Sport, Vapro AB, Västerås, Sweden) on heart rate (HR), breathing rate (BR), muscle oxygenation (SmO2) and perceived exertion at fixed submaximal workloads. METHODS: 23 active, healthy participants without asthma aged 31 ± 8 years (15 men, 8 women) performed a familiarisation test followed by two experimental trials with and without HME in a randomised, crossover design. All tests were performed at a 4% gradient on a motorised treadmill and consisted of a submaximal incremental warm-up followed by a maximal, self-paced 4-min running time trial (TT). During the familiarisation test, participants wore a portable oxygen uptake system (Metamax 3B, Cortex Biophysik, Leipzig, Germany) with the TT used to derive VO2peak. Submaximal VO2 was interpolated to derive speeds estimated to elicit 65, 70, 75 and 90% of VO2peak. In two subsequent trials performed in a climate chamber at -15 degrees Celsius, participants ran for 5 min at speeds equivalent to 65, 70 and 75% VO2peak, 3 min at 90% and 12 min at 65% VO2peak. HR and BR were monitored via a chest harness (LifeMonitor, Equivital, Cambridge, UK); mean SmO2 from the right and left quadriceps was derived using near infra-red sensors (MOXY, Fortiori Design, Hutchinson MN, USA). Data were summarised as 1 min epochs, taken from 90 to 30 s before the end of each stage. Borg 6-20 rating of perceived exertion (RPE) was reported 1 min before the end of each stage. Data were analysed using repeated-measures ANOVA and linear mixed models. The study was approved by the regional ethical review board and conducted according to the Declaration of Helsinki. RESULTS: HR was 2.5 beats/min higher during the HME trial (95% CI: 0.3 - 4.6, p=.03). In the male participants only, SmO2 was lower during the HME trial than control (-2.3%, 95% CI: -0.1 - -4.5, p=.04). The female participants reported higher RPE (0.65 AU) during the HME trial (p=.009). There was no difference in BR between the HME and control trials. CONCLUSION: Despite potentially small increases in dead space and resistance to breathing, an HME did not affect BR during submaximal exercise in -15 degrees C. However, higher HR during exercise with an HME, as well as lower SmO2 in the male participants and higher RPE in the female participants, indicates slightly higher physiological stress during steady-state exercise with an HME. It would therefore be relevant to investigate whether an HME affects maximal exercise capacity in sub-zero temperatures.
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| 3. |
- Lundesjö Kvart, Susanne, 1969-
(författare)
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Konsten att undervisa ryttare : En studie om ridlärares pedagogiska praktik
- 2020
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This thesis concerns how riding teachers’ reflect upon their teaching and how they teach. The overall aim of the thesis is to contribute with knowledge about how riding lessons are organized, regarding both the accomplishment of lessons as activity systems and the interactional organization of instructional work. Horseback riding can be understood as an embodied and practical knowledge, and includes communication and collaboration between horse and rider, sometimes referred to as equestrian feel (Dashper, 2016). Two different theoretical perspectives were applied to explore how such knowledge is taught. Activity theory (Engeström, 1987) was used to analyze interviews with and observations of ten riding teachers about their understanding and implementation of their pedagogical practice. Teachers’ and students’ interactions during riding lessons were examined using an ethnomethodological and conversation analytic approach (Goodwin, 2000; Schegloff, 1996). The analyses were based on video-recordings of ten group lessons and 40 one-on-one riding lessons.The results show that riding lessons can be conceptualized as activity systems where the focus of teaching constantly changes; from horse to student to routine. Traditions and safety regulations are shown to generate contradictions that may hinder the teachers from developing their teaching. However, the teachers express a wish to use more student collaborative methods, and display an intention to communicate with students about equestrian feel. Another result unveils how the teacher and the individual students, within the mobile context of riding lessons, make instructional sequences possible by co-creating instructional spaces. A third result illuminates the participants’ collaborative work to make equestrian feel available for instruction. The teacher molds equestrian feel through online instructions, i.e., instructions produced during the students’ active riding. These instructions shift focus between the students’ seat and influence, the horse’s actions and the student’s embodied feel. Moreover, the teachers are shown to use visual, verbal and embodied resources as they interpret equestrian feel for the student. In sum, the studies shed light on the complex art of teaching practical and embodied knowledge of riding.
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| 4. |
- Persson, Christina, 1959, et al.
(författare)
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Scandcleft Project Trial 3: Comparison of Speech Outcomes in Relation to Sequence in 2-Stage Palatal Repair Procedures in 5-Year-Olds With Unilateral Cleft Lip and Palate.
- 2020
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Ingår i: The Cleft palate-craniofacial journal : official publication of the American Cleft Palate-Craniofacial Association. - : SAGE Publications. - 1545-1569. ; 57:3, s. 352-363
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Tidskriftsartikel (refereegranskat)abstract
- To compare speech outcome following different sequencing of hard and soft palate closure between arms and centers within trial 3 and compare results to peers without cleft palate.A prospective randomized clinical trial.Two Norwegian and 2 British centers.One hundred thirty-six 5-year-olds with unilateral cleft lip and palate were randomized to either lip and soft palate closure at 3 to 4 months and hard palate closure at 12 months (arm A) or lip and hard palate closure at 3 to 4 months and soft palate closure at 12 months (arm D).A composite measure of velopharyngeal competence (VPC), overall assessment of VPC from connected speech (VPC-Rate). Percentage of consonants correct (PCC), active cleft speech characteristics (CSCs), subdivided by oral retracted and nonoral errors, and developmental speech characteristics (DSCs).Across the trial, 47% had VPC, with no statistically significant difference between arms within or across centers. Thirty-eight percent achieved a PCC score of >90%, with no difference between arms or centers. In one center, significantly more children in arm A produced ≥3 active CSCs (P < .05). Across centers, there was a statistically significant difference in active CSCs (arm D), oral retracted CSCs (arm D), and DSCs (arms A and D).Less than half of the 5-year-olds achieved VPC and around one-third achieved age-appropriate PCC scores. Cleft speech characteristics were more common in arm A, but outcomes varied within and across centers. Thus, outcome of the same surgical method can vary substantially across centers.
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| 5. |
- Persson, Helén
(författare)
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Problemet med unga i grupp
- 2020
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Ingår i: Populär Historia. - 1102-0822. ; 29:6, s. 64-65
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Recension (populärvet., debatt m.m.)abstract
- Recension av Martin Ericsson och Andrés Brink Pintos, Den bråkiga staden. Ungdomsupplopp och ungdomspolitik i efterkrigstidens Stockholm
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| 6. |
- Persson, Helén
(författare)
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Tron på spöken är ett evigt fenomen
- 2020
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Ingår i: Populär Historia. - 1102-0822. ; 29:2, s. 67-67
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Recension (populärvet., debatt m.m.)abstract
- Recension av Magnus Västerbro, Vålnadernas historia - spöken, skeptiker och drömmen om den odödliga själen
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| 7. |
- Rincon, Jonathan, 1991-, et al.
(författare)
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Mineralogy, textural characteristics and mineral chemistry of remobilised sulphides and sulphosalts in the Rävliden Norra VMS deposit, Skellefte district, northern Sweden
- 2020
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Ingår i: EGU General Assembly 2020. - : Copernicus GmBH.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Remobilisation of sulphides in metamorphosed volcanic-hosted massive sulphide deposits has been investigated in many VMS districts with regards to scale, mineral assemblages, texture and relative competence of minerals under certain p-t conditions (Gilligan & Marshall, 1987; Marshall & Gilligan, 1987). Examples of syn-tectonic remobilisation can be found at the Rävliden Norra (RVN) volcanic-hosted massive sulphide in the Skellefte district. At Rävliden, polymetallic sulphide mineralization occurs at the transition from meta-volcanic rocks of the Skellefte group rocks to the overlying Vargfors group, comprising volcaniclastic metasedimentary rocks and graphitic shales. This contribution details features of mesoscale (0.1-50 cm) remobilisation of sulphides, such as sulphide-rich veins, tension gashes, ball-ore, massive sulphides with cataclastic texture, and micro-scale features such as infilling of pressure shadows, displaying evidences of brittle and ductile deformation. Sulphide-rich veins containing sphalerite, galena, and a relative high content of Ag-sulphosalts (e.g. freibergite, pyrargyrite, pyrostilpnite) are hosted in the hanging wall (HW) of the RVN mineralization. Brittle deformation is shown in accessory quartz and calcite as bulging recrystallization, grain boundary migration and deformation lamellae or twinning. Ductile expressions include ball-ore (i.e. “durchbewegung”) textures, typically made up of two components, one composed of clasts of graphite shale or tremolite-, actinolite-, talc-altered meta-volcanic rocks and the other comprising a matrix of massive sulphide mineralization. In the massive sulphide matrix of sphalerite, chalcopyrite or pyrrhotite, micro-scale tension gashes and/or pressure shadows occur around clasts infilled by pyrrhotite, chalcopyrite, galena, freibergite, boulangerite, or gudmundite. A similar mineralogy is observed in ore lenses in the ore zone, comprising sphalerite, galena and Ag-Sb-As sulphosalts, hosted structurally above chalcopyrite + pyrrhotite stringer zones in the footwall (FW). Sulphosalts and galena present a high silver content relative to other VMS deposits in the district. This is evidenced by SEM and EMPA analysis in both HW and FW ore lenses. Argentopyrite, sternbergite and stephanite are also locally present in the HW as minor silver species hosted in veins. Inclusions of freibergite in galena contain Ag with average values of 18.4 wt. % in the HW (n=5), 18 wt. % in the massive sphalerite and ball-ore (n= 15), and 20.2 wt. % in the chalcopyrite + pyrrhotite stringer zone (n= 5). Similarly, Pb is 0.2 wt. %, 0.3 wt. %, and 0.4 wt. %, respectively. For sphalerite, Fe is on average 8.0 wt. % (n=3), 7.4 wt. % (n = 11), and 8.3 wt. % (n=3), respectively. Our preliminary results suggest that mineralization in the HW is remobilized from the main ore and textural relationships support a hypothesis that remobilisation involved a relative silver-enrichment in paragenetically later assemblages. At least two stages of deformation in the deposit can be recognized. In the first stage, sphalerite- and chalcopyrite-rich mineralization was deformed along with tremolite and talc to form a S1 foliation. The second stage involved folding of S1, and remobilisation of galena, chalcopyrite and Ag-Sb-As sulphosalts as veins or breccia infill in the HW or filling tension gaps or ball-ore, in the FW. These are often parallel to S2 crenulation or axial planes.
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| 8. |
- Rincon, Jonathan, 1991-, et al.
(författare)
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Textural and chemical characterization of sulphide minerals for improved beneficiation and exploration at the Rävliden Norra VMS deposit, Skelleftedistrict, Sweden
- 2020
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Ingår i: Abstracts and Proceedings of the Geological Society of Norway. - Oslo : Norsk Geologisk Forening. ; , s. 179-180
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Konferensbidrag (refereegranskat)abstract
- The Rävliden Norra VMS deposit, represents one of the most important new discoveries in the Skellefte district (SD) in this decade. The mineralization is hosted at the transition between Skellefte group rocks (SG), dominated by coherent rhyolitic and dacitic meta-volcanic rocks, and the Vargfors group (VG), composed of metasedimentary graphitic shale interbedded with crystal-rich, monomictic to polymictic, clast-supported mass flow deposits. The ore lenses contain massive sphalerite + galena + pyrite + pyrrhotite + chalcopyrite ± Ag-Sb-Pbsulphosalts, structurally and stratigraphically above chalcopyrite + pyrrhotite stringer mineralization. The hanging wall rocks (VG) host pyrite + pyrrhotite ± arsenopyrite mineralization. Alteration in the footwall rocks, consists of sericite, chlorite, quartz, pyrite, tremolite, actinolite, carbonate and talc. The hanging wall is less altered with limited sericite or chlorite associated with minor carbonate alteration. Post ore modifications occur as, e.g. sulphides in pressure shadows, infilling of syntectonic tension gashes, “durchbewegung” texture, and sulphide-rich veins that crosscut hanging wall rocks. Significant changes in the distribution and deportment of trace and precious elements within the deposit are evident, however the implications of these on mineral processing performance and exploration vectoring has not previously been assessed in other VMS deposits in the SD. To this end, the presence of pyrite and remobilised sulphides in both hanging wall and footwall of the Rävliden Norra mineralizations, provides an opportunity to evaluate enrichment or depletion of elements hosted in the sulphide lattices or as inclusions using LA-ICP-MS. In-situ SIMS analyses in sulphide phases will allow discrimination between sedimentary and hydrothermal sulphur in the system. An investigation into the deportment of In, Ga and Ge in sphalerite and galena, will be the first assessment of these critical elements in a VMS deposit in the SD. Ultimately, integration of elemental distribution and mineral features, such as modal mineralogy, liberation degree, and grain size, with processing variables, e.g. mineral recovery, grade or flotation kinetics; will provide a better understanding of the ore performance during concentration and beneficiation.
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| 9. |
- Tutt, Alasdair, et al.
(författare)
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A heat-and-moisture-exchanging mask affects each sex differently during exercise in sub-zero conditions
- 2020
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Konferensbidrag (refereegranskat)abstract
- Purpose: To identify how performance is affected during maximal exercise in sub-zero conditions with the use of a heat-and-moisture-exchanging mask between men and women.Methods: 23 healthy participants (eight female, 15 male; age 18-53 y) performed two simulated four-minute competition efforts including a graded warm-up at -15℃ in randomized order either with or without mask first. Breathing frequency, heart rate and velocity were measured constantly. Capillary blood samples were collected 2 min pre-and post-maximal test.Results: There was an overall negative effect of the mask on performance for both sexes (Women: -5 ± 21m; Men: -17 ± 30m, p = 0.033). Female participants accumulated more blood lactate than men during the effort with mask (9.3 ± 3.1 vs. 7.8 ± 1.4 mmol⋅L-1, p = 0.044 ). Men had an increased breathing frequency in the first 80-s of the time trial with the mask (p < 0.05). Women exhibited more even pacing, whilst men tended towards a negative pacing strategy, this observation was not affected by the mask. There was no change in heart rate between trials in either sex.Conclusions: Competition performance in both sexes is hindered by wearing a mask in sub-zero conditions. The mechanisms through which this hindrance occurs are different between sexes.Practical applications: Men and women should consider whether using a mask in short competition efforts is worthwhile for them at -15℃. Future research is required around longer competitions in sub-zero conditions.
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| 10. |
- Tutt, Alasdair, et al.
(författare)
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Heat-and-moisture exchanging masks : Advantage or a hindrance during exercise in sub-zero conditions?
- 2020
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Ingår i: Book of Abstracts of the 25th Annual Congress of the European College of Sport Science, 28th - 30th October, 2020.. - 9783981841435 ; , s. 49-50
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Konferensbidrag (refereegranskat)abstract
- INTRODUCTION: Heat-and-moisture exchanging masks (HMEs) are commonly used by athletes experiencing cold-air induced airway obstructions such as exercise-induced asthma to negate symptoms in training and competition. These masks have been demonstrated as an effective intervention at wide ranging intensity levels and duration for preventing airway obstructions (3). A large proportion of cross-country skiers experience asthma symptoms whilst training and competing in cold conditions (1, 2). As large numbers of athletes in cross country skiing and other outdoor winter endurance sports train and compete in cold conditions around the globe, links have been inferred between prolonged cold air inhalation and the development of exercise-induced asthma (2). The aim of this study was to investigate the effect of an HME on the performance (defined as distance completed) of healthy people during a maximal self-paced exercise test. METHODS: Twenty-three healthy, well-trained participants (eight females, 15 males; age 18-53 y) performed two simulated competition efforts at -15 degrees Celsius in randomized order either with or without mask first. The protocol was 5 min each at 65, 70 and 75% of VO2 Max followed by 3 min at 90% VO2 Max and a further 12 min at 65% before a 5 min pause to simulate a competition warm up followed by a 4 min maximal self-paced running test. A t-test was performed to compare performance outcomes. Two-way repeated measures ANOVA was used to examine effects of trial order and gender on performance. Linear regressions were used to investigate relationships between key physiological and biometric data and the effect of the HME on performance. All statistical analyses were performed with R using the jamovi interface. The study was conducted according to the declaration of Helsinki and approved by the regional ethics committee. RESULTS: Participants ran significantly further without HME (Mean: 931m, SD: 106m) than with HME (Mean: 918m, SD: 110m, p=0.039). No significant effect of trial order was observed (p=0.816). Body mass negatively correlated with the magnitude of the effect of the mask on performance; participants with higher body mass had a greater negative effect of the mask (r2 = 0.215, p= 0.026). No relationships were found between the effect of the HME and sex, age, ventilation, absolute or relative VO2peak. CONCLUSION: Our findings suggest that HME usage hinders maximal running performance in healthy subjects to an extent that may be sufficient to alter competition outcomes. Potential effects of sex, body mass and performance level should also be investigated further. References: 1. Larsson, K. et al. (1993), Br Med J, 307(6915), pp. 1326–1329. 2. Eriksson, L. M. et al. (2018), Scand J Med Sci Sport, 28(1), pp. 180–186. doi: 10.1111/sms.12879. 3. Nisar, M. et al. (1992), Thorax, 47(6), p. 446. doi: 10.1136/thx.47.6.446.
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