Opin vísindi
Opin vísindi er varðveislusafn vísindaefnis og doktorsritgerða í opnum aðgangi á vegum íslenskra háskóla og Landsbókasafns Íslands - Háskólabókasafns.
Opinn aðgangur að rannsóknaniðurstöðum er í samræmi við 10. gr. laga nr. 3/2003 um opinberan stuðning við vísindarannsóknir sem og kröfur innlendra og erlendra rannsóknasjóða. Markmiðið með opnum aðgangi er að niðurstöður rannsókna séu aðgengilegar sem flestum óhindrað og án endurgjalds á rafrænu formi. Vistun í varðveislusafninu er varanleg og ætlað að tryggja aðgang að vísindaefni íslenskra háskóla í opnum aðgangi um ókomna tíð. Varðveislusafnið Opin vísindi er tengt við rannsóknagáttina IRIS og rannsóknaniðurstöður í opnum aðgangi sem eru skráðar í IRIS eru um leið vistaðar og gerðar aðgengilegar til framtíðar í varðveislusafninu. Með því að safna þessu efni saman í eitt safn verður aðgangur að því einfaldur og þægilegur fyrir alla sem vilja kynna sér það og geta þannig notið þess öfluga vísindastarfs sem fram fer í háskólum landsins.
Varðveislusafnið er OpenAIRE / OpenAIREplus samhæft og samrýmist kröfum sem gerðar eru um birtingu rannsóknaniðurstaðna úr verkefnum sem styrkt eru úr evrópsku rannsóknaáætlununum FP7 og H2020.
Varðveislusafnið notar opna hugbúnaðinn DSpace.
Opinn aðgangur að rannsóknaniðurstöðum er í samræmi við 10. gr. laga nr. 3/2003 um opinberan stuðning við vísindarannsóknir sem og kröfur innlendra og erlendra rannsóknasjóða. Markmiðið með opnum aðgangi er að niðurstöður rannsókna séu aðgengilegar sem flestum óhindrað og án endurgjalds á rafrænu formi. Vistun í varðveislusafninu er varanleg og ætlað að tryggja aðgang að vísindaefni íslenskra háskóla í opnum aðgangi um ókomna tíð. Varðveislusafnið Opin vísindi er tengt við rannsóknagáttina IRIS og rannsóknaniðurstöður í opnum aðgangi sem eru skráðar í IRIS eru um leið vistaðar og gerðar aðgengilegar til framtíðar í varðveislusafninu. Með því að safna þessu efni saman í eitt safn verður aðgangur að því einfaldur og þægilegur fyrir alla sem vilja kynna sér það og geta þannig notið þess öfluga vísindastarfs sem fram fer í háskólum landsins.
Varðveislusafnið er OpenAIRE / OpenAIREplus samhæft og samrýmist kröfum sem gerðar eru um birtingu rannsóknaniðurstaðna úr verkefnum sem styrkt eru úr evrópsku rannsóknaáætlununum FP7 og H2020.
Varðveislusafnið notar opna hugbúnaðinn DSpace.
Nýlega bætt við
Determining Cluster-Specific Differences in the Number of Days Required to Reliably Predict Habitual Physical Activity : Intraclass Correlation Resampling Analysis
(2026) Murphy, Conor Jordan; Jouan, Gabriel M.; Friðgeirsdóttir, Katrin Y.; Islind, Anna Sigridur; Saavedra, Jose M.; Óskarsdóttir, María; Arnardóttir, Erna Sif; Department of Engineering; Department of Sport Science; Department of Computer Science
Background: Previous research has attempted to determine the minimum number of days of accelerometry required to reliably reflect an individual’s physical activity. However, human behaviors on a day-to-day basis can be highly variable. As a consequence, the number of days required to reliably predict habitual physical activity is dependent on the variability that exists within an individual. There is a concern that adopting generic recommendations from previous research could provide unreliable estimates by failing to represent individuals with specific physical activity patterns. Objective: The main aim of this study was to identify clusters of individuals with distinct physical activity patterns and to determine if the number of days of accelerometry data required to reliably estimate short- (7 days) and medium-term (28 days) physical activity differed between each unique cluster. Methods: Accelerometry data were retrieved from 2 independent research studies. Participants during each study had their physical activity recorded using a Withings Scanwatch (Withings Health Solutions). Following a data eligibility process, agglomerative hierarchical clustering was used to identify clusters of individuals based on their physical activity. The clusters were determined using 4 dimensions; mean, SD, skewness, and kurtosis of the step count data. Intraclass correlation coefficients (ICCs) of step count were then calculated within each physical activity cluster. A series of ICCs were computed by separately comparing the average step count across the full periods (7 and 28, for the short- and medium-term analysis, respectively) to a series of averaged subsamples (ranging from 1-6 days and 1-27 days, for the short- and medium-term analysis, respectively). For each subsample, 500 random combinations were generated and compared, providing a distribution of ICCs for each subsample. An ICC of ≥0.80 identified when the subsample of days was sufficient to achieve appropriate reliability. Results: Of 258 participant datasets, 149 were eligible for the short-term analysis and 64 were eligible for the medium-term analysis. Following agglomerative hierarchical clustering, 4 and 3 clusters of sufficient size (n≥12) were identified in the short-term and medium-term analyses, respectively. When considering the short-term analysis, to achieve a mean ICC score greater than or equal to 0.80, using all randomized combinations, the number of days ranged from 2 to 6 days depending on the physical activity cluster. For the medium-term analysis, the number of days required to achieve a mean ICC score greater than or equal to 0.80 ranged from 6 to 11 days. The short-term analysis clusters displayed more diversity in physical activity patterns than the medium-term analysis. Conclusions: Physical activity patterns influence the number of days required to estimate habitual physical activity. Thus, to avoid unreliable estimates of physical activity, which could significantly impact the interpretation of results, researchers should be mindful of the physical activity patterns of their sample before adopting generic recommendations.
Covenant Prices of U.S. Corporate Bonds
(2026-09) Handler, Lukas; Jankowitsch, Rainer; Weiss, Patrick; Department of Business and Economics
In this paper, we analyze the key drivers of bond covenant prices by employing a novel measurement approach based on secondary market data. We find that covenant prices vary significantly over time and are associated with market-wide credit risk, volatility, and macroeconomic variables. Apart from the time-series dynamics, there is also significant variation across bond and firm characteristics. In particular, covenant prices increase with the riskiness of bonds and are higher for firms that have more growth options, more tangible assets, and are smaller. Furthermore, we document a positive correlation between the prices of covenants and their subsequent inclusion rates.
Coping, Civilian Transition, and Gambling Harm Severity in UK Armed Forces Veterans
(2026-03) Ekenna, Adanma; Dekel, Dana; Engward, Hilary; Godier-MacBard, Lauren; Kay, Christopher; Kersey, Thomas; Fossey, Matt; Dymond, Simon; Department of Psychology
Veterans are prone to experiencing both mental health challenges and harm from gambling, yet little is known about the psychosocial factors that may increase risk. This study examined predictors of gambling harm severity in a sample of UK Armed Forces veterans with a focus on coping styles and reintegration into civilian employment. A cross-sectional survey was conducted among 414 former personnel using validated measures of gambling behavior, coping, and mental health symptoms including alcohol use. Of the 226 (54.6%) who had gambled in the past year, 3.1% had scores suggestive of problem gambling. Results showed that 46% of participants exhibited symptoms suggestive of posttraumatic stress disorder (PTSD), while 8.4% reported severe anxiety, 10.2% severe depression, and 11.1% high-risk alcohol use. Gambling harm severity was positively predicted by difficulties adapting to civilian employment and maladaptive coping strategies such as self-blame and substance use, while use of informational support was found to be protective. Given higher rates of primary care engagement among veterans, routine screening for gambling-related harm in such settings may improve early detection and intervention. The findings underscore the need for integrated mental health services that consider both psychological and social determinants of gambling harm severity in veterans during the military-to-civilian transition.
Constructing a corporate governance index for SMEs : How it mediates the access to finance-performance relationship
(2026-03) Bilyay-Erdoğan, Seda; Demir, Ender; Cevheroğlu Acar, Merve Gizem; Ozkan, Irem; Department of Business and Economics
SMEs play a vital role in employment, innovation, and competitiveness worldwide, yet their governance structures remain underexplored in academic research. Existing studies on corporate governance predominantly focus on large publicly traded firms, leaving a gap in our understanding of how governance mechanisms operate in SMEs. To fill this gap, the primary purpose of this study is to introduce a novel and comprehensive corporate governance index tailored specifically to SMEs. Using stratified sampling, we conducted a structured survey of 469 SMEs across diverse sectors and firm sizes in Türkiye. This index comprises six subdimensions: board structure, family involvement, female participation, digitalization, corporate accountability, and succession, and its internal validity is confirmed with Cronbach's alpha values above 0.70 for the overall index and most subindices. The second purpose of this study is to investigate the relationship between access to finance and SME performance, emphasizing the mediating role of corporate governance. Using cross-sectional regression analysis, our results show that access to finance significantly improves SME performance. We also find that corporate governance not only enhances performance directly but also mediates this positive association. To the best of our knowledge, this is the first study to demonstrate that access to finance influences SME performance through both direct and indirect channels. Overall, our findings highlight that effective governance structures are essential to maximize the benefits of access to finance. This finding underscores the role of institutional and managerial factors in enhancing firm-level competitiveness by enabling SMEs to leverage access to finance and governance practices to achieve sustainable growth.
A Rotation-Controlled Anisotropic Hourglass Metasurface for Multiband Reflective Linear-to-Circular and Cross- Polarization Conversion
(2026) Nasir, Muhammad; Koziel, Slawomir; Pietrenko-Dabrowska, Anna; Department of Engineering
This paper presents and experimentally validates a multifunctional anisotropic metasurface (MS) that exhibits linear-to-linear (LTL) reflective cross-polarization (RCP) and circular polarization conversion (CPC) responses across multiple frequency ranges. The proposed MS integrates a single-layer design consisting of 45° oriented truncated circular ring and an hourglass-like structure, providing four LTL-RCP conversion bands (2.41 - 2.48, 3.16 - 3.46, 5.80 - 6.59, and 11.64 - 13.75) GHz with polarization conversion ratio (PCR) exceeding 95%, and seven CPC bands (2.33 - 2.38, 2.55 - 2.99, 3.69 - 5.37, 7.13 - 10.92, 13.95 - 14.25, 14.93 - 15.17, and 15.31 - 15.56) GHz with the axial ratio (AR) less than 3 dB, covering the S-, C-, X-, and Ku-bands. By only adjusting the angle of the hourglass structure at 15° within the same structure, LTL-RCP with PCR greater than 95% is realized in the frequency bands from 13.71 to 14.64 GHz, along with ≤ 3 dB of AR is achieved at four additional CPC bands at (2.20 - 2.36, 2.95 - 8.41, 10.84 - 12.30, and 14.84 - 15.06) GHz. The polarization conversion mechanisms are explained through detailed surface-current distributions analysis and full-wave electromagnetic (EM) simulations. Furthermore, the proposed concept is validated through the measurements of the fabricated prototype consisting of 8× 13 -unit cells. The measurement results are in excellent agreement with the simulation predictions. The proposed MS design demonstrates a simple yet effective solution for achieving tunable multi-band polarization manipulation without structural modification, making it suitable for advanced EM communication applications.
Flokkar í Opnum vísindum
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- University of Iceland
- University of Akureyri
- Bifröst University
- Hólar University College
- IRIS
- Agricultural University of Iceland
- National and University Library of Iceland
- Iceland University of the Arts