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Origin and age of the near-rift Fjallgarðar Volcanic Ridge, Northeast Iceland
(University of Iceland, School of Engineering and Natural Sciences, Faculty of Earth Sciences, 2026-09) Löw, Noëmi; Sæmundur Ari Halldórsson; Faculty of Earth Sciences (UI); Jarðvísindadeild (HÍ); School of Engineering and Natural Sciences (UI); Verkfræði- og náttúruvísindasvið (HÍ)
The Fjallgarðar Volcanic Ridge (FVR) is a ~200 km long subglacially erupted volcanic ridge east of and parallel to the Northern Rift Zone in Iceland. Despite its size and prominent geomorphology, its origin and relationship to nearby volcanic systems and rift zone segments remain poorly constrained. This thesis investigates the origin and age of the FVR through an integrated study - petrology, geochemistry, radiogenic and helium isotope characteristics, and 40Ar/39Ar geochronological dating. The results reveal that the FVR was active between ~790 and ~100 ka and erupted exclusively during glacial periods. Two compositionally distinct basalt groups are identified throughout the FVR: a depleted tholeiitic suite and a more enriched suite. The depleted group dominated the early phase of FVR volcanism, where the geochemical and isotopic compositions suggest a clear link to source materials associated with the Icelandic mantle plume. In contrast, the enriched group, which appeared at ~400 ka, preserves geochemical characteristics of the Kverkfjöll volcano, underneath which magmas were stored before being transported laterally through longdistance dyke propagation to the FVR. The trace element and isotope data suggests that the depleted FVR basalt group was likely generated from upwelling of the plume material beneath Central Iceland and transported to the FVR analogously to the magmas from Kverkfjöll. In tandem, the depleted magmas may also have formed beneath a thicker lithospheric lid beneath or east of the FVR after plume-derived material bypassed the main rift melting zone and dispersed beneath northeastern Iceland during a period of enhanced plume flux.
Verk
Per- and polyfluoroalkyl substances (PFASs) meet Arctic and sub-Arctic marine diatoms and associated symbionts
(Háskólinn á Akureyri, 2026-10) Arulananthan, Ashani; Vilhelmsson, Oddur Þór; Scholz, Bettina; Sigurbjörnsdóttir, Margrét Auður; Rolfsson, Óttar; Grossart, Hans Peter; Karsten, Ulf; Centre for Doctoral Studies
Á undanförnum áratugum hafa fjölflúorsetin alkýlefni (PFAS) komið fram sem útbreidd mengunarefni, sem hafa greinst jafnvel á afskekktum svæðum á borð við Norðurskautið og Suðurskautslandið, með víðtæk áhrif á heilsu manna og vistkerfa. Sérstakar áhyggjur hafa vaknað vegna útbreiðslu PFAS og mögulegra áhrifa þeirra á lykillífverur í fæðuvefjum, svo sem kísilþörunga, sem eru stór hópur svifþörunga og gegna lykilhlutverki í lífefnafræðilegum hringrásum með því að standa undir um 20% af frumframleiðslu jarðar. Markmið þessarar ritgerðar var að rannsaka áhrif PFAS á tvær vistfræðilega ólíkar tegundir sjávarkísilþörunga, uppsjávartegundina Thalassiosira pseudonana og botnlægu tegundina Cylindrotheca closterium, og meta áhrif þeirra á lífeðlisfræði þörunganna, genatjáningu þeirra og á sambýlisörverur þeirra. Báðar tegundirnar voru ræktaðar í viðurvist langkeðja PFAS efnasambanda yfir styrkhallanda í skammtímatilraunum, auk langvarandi snertingar við PFASblöndu í styrk áþekkum þeim sem mælist í sjó á Norðurslóðum. Mældir voru lífeðlisfræðilegir þættir tengdir vexti, ljóstillífun, oxunarálagi og frumuefnasamsetningu. Þessar niðurstöður voru síðan samþættar greiningum á genatjáningu, markvissri efnaskiptagreiningu innan frumna (endometabolome) og breytingum á bakteríusamfélögum tengdum kísilþörungunum. Skammtímatilraunirnar sýndu marktæka vaxtarhömlun hjá báðum tegundum við háa (100 mg/L) og miðlungs (1 mg/L) PFAS-styrki, þar sem blöndur höfðu sterkari áhrif en einstök efni. Viðbrögðin voru þó tegundasértæk. C. closterium reyndist næmari fyrir perflúoraðri karboxýlsýrum (PFCAs; C8-C12), en T. pseudonana varð fyrir meiri áhrifum af PFAS-efnum með kolefniskeðjur lengri en C11. PFAS-útsetning dró úr ljóstillífunarvirkni, blaðgrænumagni og próteininnihaldi, en jók á sama tíma streituvísa eins og prólín og heildarvirkni andoxunarkerfa. Við langvarandi útsetningu fyrir PFAS-blöndu (0,9 ng/L) náðu vaxtarhraðar sér aftur á strik eftir 14 daga og urðu sambærilegir við samanburðarhópa, sem bendir til mögulegra aðlögunar- eða uppbótarviðbragða. Á sameindastigi sýndi T. pseudonana víðtæk áhrif PFAS á marga grunnefnaskiptaferla, en svörun C. closterium var markvissari og einkenndist einkum af aukinni virkni ABC-flutningspróteina og breytingum í miðlægum kolefnaefnaskiptum. Breytingar í efnaskiptum og genatjáningu hjá T. pseudonana bentu til tilfærslu frá vaxtarhvetjandi ástandi með mikla köfnunarefnisþörf yfir í streituaðlagaða svipgerð sem lagði meiri áherslu á viðhald oxunar-jafnvægis, viðgerð frumuhimna og myndun verndandi afleiddra efnasambanda fremur en áframhaldandi vöxt. PFAS-útsetning leiddi einnig til endurskipulagningar bakteríusamfélaga tengdra kísilþörungunum á hýsilháðan hátt, þó án verulegra breytinga á alfa-fjölbreytni, sem bendir til breytinga á samfélagsgerð frekar en hruns samfélaganna.
Verk
A qualitative analysis of the experience of gambling harm and accessing support among United Kingdom Armed Forces personnel
(2025-12) Champion, Hannah; Biggar, Blair; Jones, Matthew; Larcombe, Justyn; Fossey, Matt; Dymond, Simon; Department of Psychology
Background: Military personnel (both currently serving and veterans) are vulnerable to harm from gambling, yet many are reluctant to seek help. The aims of this study were to explore the lived experience of gambling and gambling harm in currently serving members of the UK Armed Forces and to seek to improve military-specific gambling harm information and support. Methods: Semi-structured interviews were undertaken with self-selected currently serving personnel from the UK Armed Forces. Interview questions focus on lived experience of gambling harm, motivators and triggers around gambling, and awareness of gambling information and support. Results: Thematic analysis identified four main themes: (1) sociocultural pathways to gambling harm; (2) influencing factors unique to military life; (3) obstacles to early intervention and support; and (4) facilitators of help and support. Conclusions: Findings showed that the nature and extent of gambling harm within the UK Armed Forces may not be fully acknowledged, and that currently serving personnel face barriers accessing safer gambling information and support. Specifically, there was a lack of education around the nature of gambling harm, identifying it, how to go about seeking help, and from whom. The normalisation of potentially harmful behaviour, stigmatising attitudes, and concerns around anonymity serve as further barriers to help-seeking. There is a need to raise awareness, reduce stigma, and enhance support for gambling harm within the UK Armed Forces.
Verk
AppCon : Mitigating evasion attacks to ML cyber detectors
(2020-04-01) Apruzzese, Giovanni; Andreolini, Mauro; Marchetti, Mirco; Colacino, Vincenzo Giuseppe; Russo, Giacomo; Department of Computer Science
Adversarial attacks represent a critical issue that prevents the reliable integration of machine learning methods into cyber defense systems. Past work has shown that even proficient detectors are highly affected just by small perturbations to malicious samples, and that existing countermeasures are immature. We address this problem by presenting AppCon, an original approach to harden intrusion detectors against adversarial evasion attacks. Our proposal leverages the integration of ensemble learning to realistic network environments, by combining layers of detectors devoted to monitor the behavior of the applications employed by the organization. Our proposal is validated through extensive experiments performed in heterogeneous network settings simulating botnet detection scenarios, and consider detectors based on distinct machine-and deep-learning algorithms. The results demonstrate the effectiveness of AppCon in mitigating the dangerous threat of adversarial attacks in over 75% of the considered evasion attempts, while not being affected by the limitations of existing countermeasures, such as performance degradation in non-adversarial settings. For these reasons, our proposal represents a valuable contribution to the development of more secure cyber defense platforms.
Verk
A novel mobile application to examine impaired vigilance through digital means
(2025-12) Pahari, Purbanka; Schmitz, Lisa; Richert, Elena; Jóhannsdóttir, Kamilla Rún; Kristbergsdóttir, Hlín; Korkalainen, Henri; Töyräs, Juha; Leppänen, Timo; Nikkonen, Sami; Arnardottir, Erna Sif; Islind, Anna Sigridur; Department of Engineering; Department of Psychology; Department of Computer Science
The psychomotor vigilance task (PVT) is a three to thirty-minute test widely used to measure alertness and vigilance. However, only a few comprehensively validated PVTs are currently available through digital means, e.g., mobile devices. Thus, the present study aimed to investigate the usefulness of a novel three-minute PVT (PVTSR) delivered through a touchscreen mobile device. The present study comprised 41 healthy or undiagnosed with obstructive sleep apnea participants recruited through local advertisement in Reykjavik, Iceland between 2021 and 2022. First, participants completed an in-lab ten-minute standard PVT (PVTstd) on a computer with the Inquisit software at Reykjavik University Sleep Institute. Later, the same participants completed a three-minute PVTSR in the Sleep Revolution mobile application at home. With a paired sample t-test, differences between the PVT outputs, i.e., mean reaction time (RT) and median RT, were compared between PVTstd and PVTSR. In addition, effect sizes and Pearson correlations between the PVTstd and PVTSR outcomes were evaluated. The average mean RT (PVTstd: 350.2 ms; PVTSR: 424.1 ms) and median RT (PVTstd: 334.4 ms; PVTSR: 415.2 ms) were significantly (p < 0.001) shorter in PVTstd compared to PVTSR. The effect sizes for mean RT and median RT were 0.70 and 0.79, respectively. In addition, the correlations of mean RT (r = 0.96, 95% confidence interval (CI): 0.92–0.98) and median RT (r = 0.94, 95% CI: 0.89–0.97) between PVTstd and PVTSR were high. Although median and mean reaction times were systematically higher when measured with the mobile application, there was a strong correlation between the methods’ outcomes. After accounting for this systematic increase, the novel PVTSR approach shows potential for evaluating impaired vigilance. With future fine-tuning to adjust for the systematic delay, this readily available three-minute test could enable long-term follow-up of impaired vigilance in participants’ homes.

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