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More than the shoulder? Kinematics of the jump throw and factors influencing shoulder problems in handball
(University of Iceland, School of Health Sciences, Faculty of Medicine, 2025-11-21) Árnason, Kári; Kristín Briem, Atli Ágústsson; Læknadeild (HÍ); Faculty of Medicine (UI); Heilbrigðisvísindasvið (HÍ); School of Health Sciences (UI)
Aims: Shoulder problems are common in handball and known risk factors include decreased shoulder rotational strength, limited shoulder rotational mobility, and sudden increases in training and competition load. The throwing motion is a large movement, and previous research has linked proximal segments´ force production to throwing velocity. Nevertheless, the influence of lower body strength and trunk rotation power (TRP) on shoulder problems in handball players has not been investigated prospectively. Similarly, the association between internal shoulder load (subjective perception of load) vs. external shoulder load (e.g. number of throws in a match) measurements and shoulder problems among handball players is unknown. Despite the jump throw being the most common throwing technique in handball, very few motion analyses of it have been conducted. Moreover, the extent to which proximal segments’ kinematics influence more distal segments, such as the shoulder, is unknown, as are possible kinematic differences between different positions. The aims of this thesis were to examine the association between pre-season strength and power in the lower body and trunk, and shoulder problems among handball players, to perform a 3D motion analysis of the jump throw and, to investigate whether internal or external shoulder load measurements were more consistently associated with shoulder problems. Increased knowledge of this topic might influence injury prevention via better load management, either by ensuring adequate pre-season strength and power or by regulating training/competition shoulder load.Methods: This thesis is based on results from three research papers. Paper I included 42 male handball players. Pre-season measurements of peak lower body strength, peak trunk rotation power (TRP), and peak external and internal rotation strength in the throwing shoulder were conducted before the 2022–2023 season. Participants were followed throughout a whole regular season (31 weeks), where they answered a weekly questionnaire specially designed to document the prevalence and severity of overuse problems, and an additional question regarding participation-related shoulder load (PSL – subjective experience of shoulder load (internal load)) during the previous week. Paper II involved 31 female handball players. The same pre-season protocol as used in paper I was conducted before the 2023–2024 season and participants answered the same questionnaire throughout the season (29 weeks). Performance data, including the total number of shots per player in all league matches were collected from HBstatz (official statistical provider for the Icelandic Handball Federation) and defined as external shoulder load. For paper I and II, the association between pre-season strength and power and the prevalence and severity of shoulder problems was assessed with the Spearman´s rho correlation coefficient. The influence of pre-season strength and power on the association between internal and external shoulder load, and the severity of shoulder problems was examined with a mixed model ANOVA. Paper III involved a 3D motion analysis of 41 male top-division players performing a jump throw, conducted before the 2022–2023 season. The correlation between proximal and distal segments´ kinematics was assessed and differences in jump throw kinematics between playing positions were analysed with an independent t-test. The explanatory strength of proximal segments´ kinematics on the variance in shoulder internal rotation (IR) angular velocity was assessed by using a stepwise regression model. Results: The results from paper I (male players) showed a negative correlation between pre-season ER strength and the prevalence of shoulder problems (rs=-0.34, p=0.029). A main effect was observed showing a positive relationship between PSL and the severity of shoulder problems (p<0.001). A significant interaction was observed between PSL and pre-season TRP in terms of their influence on the severity of shoulder problems, as males with pre-season TRP one standard deviation (SD) below the group´s mean had a stronger association between the severity score and PSL. The findings from paper II (female players) showed a positive correlation between peak lower body strength (rs=0.40, p=0.03) and peak ER shoulder strength (rs=0.38, p=0.04), and the prevalence of substantial shoulder problems. A main effect was again observed for PSL, with higher PSL associated with higher severity score (p<0.001). However, a negative association was found between the external shoulder load and the severity of shoulder problems (p=0.04). A significant interaction was observed between PSL and peak lower body strength, TRP, and ER shoulder strength in terms of their influence on the severity of shoulder problems. Female players with pre-season strength and power one SD above the group´s mean showed a stronger association between the severity score and PSL. Paper III showed that hip and pelvis kinematics explained 44% of the variance in shoulder IR angular velocity. Significant differences were found between positions with center/back players displaying higher angular velocities in all measured segments, except trunk rotation, and greater range of motion excursion in the hips, pelvis, and trunk compared to wing/pivot players. Conclusions: The findings suggest that low pre-season TRP in male players may make the throwing shoulder more vulnerable for an increase in load. Pre-season training should therefore emphasize TRP training for male players. However, the results highlight the complex interaction between multiple risk factors for shoulder problems in female players and suggest that PSL (internal load) is more consistently associated with shoulder problems in handball, compared to external load. The results also underscore the role of proximal segments´ kinematics in terms of an efficient jump throw performance, and that different on-field demands likely influence kinematic differences between central/back vs wing/pivot players. It is therefore important to tailor strength training accordingly to each player’s on-field demands.
Verk
Munnleg lokapróf í háskólakennslu : Kostir áskoranir og upplifun nemenda
(2025-09-29) Kristjánsdóttir, Vera Kristín Vestmann; Viðskiptadeild
Munnleg lokapróf eru sjaldgæf í íslensku háskólakerfi þrátt fyrir aldalanga sögu. Sumar rannsóknir benda til þess að þau bjóði upp á dýpri innsýn í þekkingu og hæfni nemenda og geti þannig endurspeglað námsárangur með öðrum hætti en hefðbundin skrifleg próf. Í þessari grein er fjallað um munnleg próf sem matsaðferð í háskólakennslu, skoðaðir bæði kostir þeirra og áskoranir. Áhersla er lögð á upplifun nemenda, streitu og prófkvíða, auk þess sem borinn er saman árangur nemenda í munnlegum og skriflegum prófum. Rannsóknin byggir á spurningakönnun sem lögð var fyrir nemendur í námskeiði í viðskiptafræði við Háskólann á Akureyri, þar sem munnlegt lokapróf var tekið upp í stað hefðbundins skriflegs prófs. Niðurstöður sýna að þrátt fyrir að margir nemendur upplifi kvíða tengdan munnlegum prófum, meta þeir reynsluna yfirleitt jákvæða eftir á. Upplifun nemenda af að þreyta munnlegt próf reyndist marktækt ólík eftir því hvort þeir upplifðu streitu í prófinu eða ekki. Meirihluti þátttakenda taldi að munnlegt próf krefðist dýpri skilnings og þeir hefðu þar af leiðandi undirbúið sig betur fyrir prófið. Gögnin sýna einnig að meðaleinkunnir voru hærri hjá þeim nemendum sem þreyttu munnlegt próf en hjá fyrri árgöngum sem tóku hefðbundið skriflegt próf. Rannsóknin dregur fram mikilvægi þess að styðja nemendur í gegnum nýjar matsaðferðir og að munnleg próf geti stuðlað að réttlátara námsmati. Niðurstöðurnar styðja við fyrri rannsóknir sem benda til þess að munnleg próf geti verið áhrifaríkari leið til að meta dýpri skilning en skrifleg próf og efli mikilvæga hæfni fyrir atvinnulífið.
Verk
Teachers' Attitudes and Perceptions of the Usefulness of AI in Academia: How should universities respond to a changing Educational Landscape?
(IATED Academy, 2025) Schram, Ásta Bryndís; Jóhannesdóttir, Sigurbjörg; Einarsson, Hafsteinn; Bjarnadóttir, María Kristín; Rogers, Bethany Louise; Gómez Chova, Luis; González Martínez, Chelo; Lees, Johanna; Faculty of Sociology, Anthropology and Folkloristics; Faculty of Industrial Engineering, Mechanical Engineering and Computer Science; Faculty of Philosophy, History and Archaeology; Health Sciences
Gervigreind (AI) er hratt að umbreyta háskólamenntun og kallar á að háskólar endurskoði kennslufræðilega umgjörð, stuðningskerfi og siðareglur. Þrátt fyrir aukna notkun gervigreindarverkfæra í fræðilegu samhengi hafa háskólar oft brugðist við á viðbragðsfrekan hátt og einblínt þröngt á fræðilegan heiðarleika í stað heildrænna innleiðingarstefna. Í þessari rannsókn eru könnuð viðhorf, notkunarmynstur og stuðningsþarfir kennara við Háskóla Íslands í tengslum við notkun gervigreindar í kennslu og niðurstöðurnar veita grunnupplýsingar sem nýtast til framtíðarstefnumótunar og þróunar kennarastuðnings. Vorið 2025 var lagður fyrir spurningalisti með 79 atriðum og sex opnum spurningum til 2.003 háskólakennara, þar á meðal stundakennara. Alls bárust 339 svör (17% svarhlutfall; 33% meðal fastráðinna kennara). Megindleg gögn voru greind með lýsandi tölfræði og eigindleg svör með þemagreiningu með ályktandi nálgun. Niðurstöður sýna að þótt meirihluti þátttakenda hafi jákvætt viðhorf til gervigreindar er samþætting hennar í kennslufræði enn lítil. Flestir nota gervigreind til stuðningsverkefna, svo sem til að fá hugmyndir að verkefnum (39%), þróa kennsluefni (35%), búa til prófspurningar (30%) eða hanna matsviðmið (24%). Fáir kennarar nota gervigreind í flókin verkefni á borð við hermilíkön, gagnaúrvinnslu eða þjálfun spjallvéla. ChatGPT var langalgengasta verkfærið (62%), næst á eftir komu Copilot (29%) og Gemini (14%). Hæsta áskriftartíðni var einnig hjá ChatGPT (12%), síðan Claude (3%) og bæði Scite og Copilot 365 með 2%. Helstu hindranir í innleiðingu voru áhyggjur af misnotkun nemenda (89%), fleipri gervigreindar (76%), siðferðilegum álitaefnum (71%), persónuvernd (69%) og hlutdrægni í svörum (68%). Kennarar bentu einnig á skort á leiðbeiningum og upplýsingum frá stofnun (62%), skort á stuðningi (49%) og takmarkaða eigin þekkingu (48%). Í opnum svörum kom skýrt fram þörf fyrir heildstæðar þjálfunaráætlanir, faggreinasértækan og persónubundinn stuðning, háskólagreiddan aðgang að gervigreindarverkfærum og skýrar reglur um siðferðilega og kennslufræðilega notkun. Kennarar voru varfærnislega bjartsýnir á möguleika gervigreindar til að auka skilvirkni og skapandi nálganir í kennslu en lögðu áherslu á mikilvægi mannlegra þátta í námi. Rannsóknin varpar ljósi á mikilvægt bil milli áhuga og raunverulegrar innleiðingar og bendir til þess að háskólar þurfi að stíga út fyrir viðbragðsmiðuð skref og þróa trausta, þverfaglega umgjörð fyrir samþættingu gervigreindar. Þessi frumrannsókn veitir grunnupplýsingar um reynslu kennara við Háskóla Íslands og undirstrikar brýna þörf fyrir aðgerðir af hálfu skólans. Háskólinn þarf að forgangsraða verklegri þjálfun, siðferðilegri leiðsögn og stuðningi við innviði til að tryggja að kennarar séu vel undirbúnir til að starfa í hratt breytilegu menntunarlandslagi. Framhaldsrannsóknir ættu að kanna mun á viðhorfum milli fræðigreina, aldurshópa og starfshlutfalla, auk þess að fylgjast með langtímaþróun eftir því sem gervigreind verður meira samþætt fræðastarfi.
Verk
Understanding Hydrogen Sulfide Mineral Storage: Joint Geophysical Surveying and Geochemical Modeling at the Nesjavellir Geothermal Site, Iceland
(University of Iceland, School of Engineering and Natural Sciences, Faculty of Earth Sciences, 2025-12-05) Ciraula, Daniel; Halldór Geirsson; Faculty of Earth Sciences; Jarðvísindadeild; School of Engineering and Natural Sciences; Verkfræði- og náttúruvísindi
The physical and chemical processes that occur in the subsurface as fluids and rocks interact play a central role in shaping subsurface geochemical systems. However, capturing these fluid-rock interactions in the field is difficult, as these processes occur hidden from direct observation. Both geochemical and geophysical methods provide complementary insights into the complex fluid-rock interactions, but the disciplines are not commonly used together. This thesis aims to integrate reactive transport geochemical modeling with time-lapse geophysical surveying to better understand and monitor fluid-rock interactions associated with hydrogen sulfide (H₂S) mineral storage in basalt, focusing on the Nesjavellir geothermal site (SW Iceland). In the mineral storage approach, injected H₂S reacts with basalt-sourced iron to form the mineral pyrite. The direct current and induced polarization (DCIP) geophysical method is sensitive to pyrite abundance through the chargeability parameter and is therefore evaluated as a novel monitoring tool for H₂S mineral storage. This research integrates DCIP surveying with reactive transport models that couple fluid flow and transport with geochemical reactions to predict the fluid-rock interactions and provide insight into geochemical processes controlling the DCIP response. Reactive transport models presented here show that H₂S mineral storage is effective under the current injection conditions, with up to 87% of the injected H₂S mineralizing as pyrite over 25 years of continuous injection. Consequently, H₂S contamination of the nearby Lake Thingvellir is expected to be minimal (<0.013 µmol/L). However, faults with high permeability pose a potential risk for contaminating the surface water. Lithologic and hydrologic controls strongly impact H₂S mineralization: it is greatest in high-permeability hyaloclastites with abundant basaltic glass and in fresh, olivine-rich lava flows; high porosity and temperature accelerate iron release and pyrite formation; and permeability governs the spatial distribution of pyrite precipitation, although high fluid flow in permeable zones can limit the fluid-rock interactions required for pyrite formation. H₂S mineralization is maximized in high-permeability hyaloclastites containing abundant basaltic glass and fresh lava flows containing abundant Fe-rich olivine. High porosity and elevated temperature accelerate basalt dissolution and iron release, enhancing H₂S mineralization. Permeability controls the spatial distribution of H₂S-rich water and subsequent pyrite precipitation. However, high fluid flow rates in permeable zones can limit fluid-rock interactions. Inversion of the 3D flow model constrained by borehole fluid temperature data reveals high permeabilities up to 9.7×10⁻¹¹ m² in hyaloclastite units. The permeability values agree with estimates derived from a petrophysical relationship linking permeability, changes in electrical resistivity between 1985 and 2020, and smectite abundance, as predicted by reactive transport simulations over the same period. Multiple-porosity models indicate that slow, diffusion-dominated transport in the rock matrix enhances fluid–rock interactions, with up to 97% of the total pyrite formation occurring within the rock matrix. This highlights the importance of considering diffusive processes in multiple-porosity frameworks to accurately simulate H₂S mineral storage in fractured basalt. Assessing DCIP monitoring capabilities at Nesjavellir shows increases in chargeability in wireline DCIP logs from injection wells injecting H₂S-rich water at rates of 12.5-149 L/s. The wireline measurements, taken 40 days apart, capture changes consistent with reactive transport model predictions of pyrite formation within 3.25 m of the borehole. In contrast, DCIP surface measurements show no significant change in chargeability following six months of continuous injection. Field-scale reactive transport models illustrate that low signal-to-noise ratios at the injection depths and small chargeability responses from dispersed pyrite mineralization limit the monitoring capability of surface DCIP. Synthetic DCIP datasets generated from reactive transport models show that cross-borehole DCIP surveying improves upon the surface DCIP approach by measuring chargeability changes at injection depths, but the method remains limited by data noise and weak chargeability signals. Overall, this thesis provides innovative ways of integrating geochemical and geophysical approaches and provides a comprehensive, non-invasive approach to enhance hydrogeological monitoring capabilities.
Verk
Resolution by case syncretism in Icelandic passives
(Graduate Linguistics Student Association, 2024-12-06) Snorrason, Oddur; Wood, Jim; Sigurðsson, Einar Freyr; Stofnun Árna Magnússonar í íslenskum fræðum; The Árni Magnússon Institute for Icelandic Studies