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Tengsl lífvísa í heila- og mænuvökva við einkennandi meingerð Alzheimer-sjúkdóms og vitræna skerðingu
No full textThe focus has shifted in recent years from clinical towards a biological definition of Alzheimer’s disease (AD), as pathophysiological changes precede the clinical symptoms by decades. In vivo brain imaging and cerebrospinal fluid (CSF) biomarkers have been at the center of this change. The core biomarkers are amyloid beta (Aβ), phosphorylated tau (P-tau) and total tau (T-tau), reflecting signature aspects of AD pathology (Aβ plaques, neurofibrillary tangles and neurodegeneration). Although the diagnostic accuracies of these markers are satisfactory, their levels reach a plateau at later stages of the disease and do not associate well with the progression of cognitive impairment. The discovery of novel biomarkers is therefore of importance for a better understanding of different biological processes driving the pathology and clinical manifestation of the disease. The overall objective of the project was to evaluate the relationships of selected CSF biomarkers with signature AD pathology and cognitive functions among individuals at the symptomatic pre- or early stages of dementia.
Recent findings suggest that dysfunction in neuroinflammation, lipid metabolism and cholinergic neurons play a critical part in the pathogenesis of AD. In this study, we measured novel biomarkers reflecting these different biological processes. Subjects were recruited from The Icelandic MCI study, which included individuals referred to the Landspitali University Hospital (LUH) Memory Clinic. The criteria for inclusion were a score between 24-30 on the Mini-Mental State Examination (MMSE) and a score of 4.0 or less on the Informant Questionnaire on Cognitive Decline in the Elderly (IQCODE) at the first visit. For this project, only subjects who underwent lumbar puncture were recruited from the cohort. All subjects were categorized as having a CSF AD profile reflecting signature AD pathology or non-AD profile, based on a cut-off point (0.52) between the ratio of T-tau and Aβ42 values in CSF.
The aim of Paper I was to evaluate the association of CSF biomarkers reflecting neurodegeneration (neurofilament light [NFL]) and inflammation (chitinase-3-like protein 1 [YKL-40], S100 calcium-binding protein B [S100B], glial fibrillary acidic protein [GFAP]) with CSF AD profile and cognitive decline. Our results showed that although the markers did not accurately differentiate between the two CSF profiles, they associated in different ways with certain cognitive domains. These relationships were mainly observed among subjects with a CSF AD profile, where higher levels of NFL associated with deficits in verbal episodic memory and higher levels of GFAP with deficits in processing speed.
The aim of Paper II was to identify lipid species best distinguishing between CSF profiles (AD and non-AD), and to examine their relationships with measures reflecting AD-related processes (neurodegeneration, inflammation, impairment in verbal episodic memory). Untargeted CSF lipidomic analysis was performed for the detection of mass-to-charge ratio (m/z) features, by the application of ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS). Out of 1008 features detected, eight were selected as best differentiating between the two CSF profiles. One out of the eight features was assigned to a lipid species (C18 ceramide), as it was the only one to be confirmed with high confidence. Lower levels of Aβ42 and higher levels of T-tau related to higher levels of C18 ceramide. Additionally, a positive relationship was found beween levels of inflammatory marker S100B and C18 ceramide.
The aim of Paper III was to assess the association between the activity of cholinesterase enzymes acetylcholine (AChE) and butyrylcholinesterase (BuChE) in CSF and measures reflecting AD-related processes (amyloidosis, neurodegeneration, inflammation, impairment in verbal episodic memory). CSF AChE and BuChE activity did not associate with amyloid status in the brain. Higher levels of T-tau and P-tau related to higher activity of AChE, and to a lesser extent, higher activity of BuChE. Higher levels of inflammatory markers S100B and YKL-40 also related to higher levels of both AChE and BuChE activity.
Overall, these results indicate the potential value of novel CSF biomarkers regarding diagnosis, progression and treatment of AD at the early stages of the disease. Higher levels of C18 ceramide related to AD pathology and inflammatory processes, indicating a potential as a therapeutic target and an additional diagnostic marker. The activity of ACh-degrading cholinergic enzymes related to inflammatory and neurodegenerative processes. Proteins NFL and GFAP, measured in CSF, are promising markers for cognitive decline and progression among individuals with signature AD pathology
Creative Mathematics - Professional Development in an Icelandic Compulsory School
Get PDFCreativity is an important component in education. Modern society with an unknown future calls for creative individuals who develop new ideas and solve problems in a creative manner. Computers have taken over much of the routine work in mathematics and other sciences, but these fields call for creativity, cooperation, and perseverance. However, mathematics taught in schools often lacks creativity and focuses on solving routine problems with given algorithms. Although some teachers see the value of creativity for mathematics learning, they struggle to foster this important component in their classrooms. This action research focused on a professional development program in an Icelandic compulsory school. The program intends to support teachers to foster creativity in their mathematics classrooms. The teachers partake in seminars and work towards bringing their learning into their classrooms. Data was gathered from seminars and work with teachers. The data was analyzed qualitatively and included interviews, surveys, videos, field notes, and reflective journals. Case studies were chosen to see how the teachers explain the effect of the program on their views, pedagogy, teaching practices and student learning. The case studies revealed that professional development on creative learning can influence teachers’ pedagogy and practice. The results further brought to light aspects for learning that have been developed into a model for creative mathematics learning. This model brings together the components of play and games, hands-on learning, and conversation in mathematics. These aspects helped the teachers bring the students to deeper learning modalities that connect to creative mathematics learning for the students. By partaking in this process, the teachers found that their views, teaching, and student learning were altered. They described barriers of time, student group size, learning space, standardized tests and limiting teaching materials. These research results and development of the PD program have value for teachers, teacher educators, those planning professional development, school management and policy makers.Sköpun skiptir sköpum fyrir menntun. Nútímasamfélag kallar eftir einstaklingum sem geta þróað nýjar hugmyndir og leyst vandamál óvissrar framtíðar. Tölvur hafa tekið yfir mikið af hefðbundnum aðgerðum í stærðfræði og vísindum en þörf er á sköpun, samvinnu og þrautseigju fyrir framþróun þessara greina. Þrátt fyrir það er stærðfræðin sem kennd er í skólum oft ekki skapandi og byggist á því að leysa hefðbundin verkefni með fyrirfram gefnum reikniritum. Jafnvel þó að sumir kennarar sjái gildi þess að leggja áherslu á sköpun í stærðfræðinámi eiga þeir erfitt með að efla þennan mikilvæga þátt í kennslu sinni. Þessi starfendarannsókn snýr að starfsþróun í íslenskum grunnskóla. Starfsþróunin leitast við að styðja kennara til þess að efla sköpun í stærðfræðinámi. Gögnum var safnað frá námskeiðum og í vinnu með kennurum. Gögnin voru greind með eigindlegum aðferðum og byggðu á viðtölum, könnunum, myndböndum, vettvangsnótum og ígrundunardagbókum. Tilvik voru valin til þess að skoða hvernig kennararnir lýstu áhrifum starfsþróunarinnar á viðhorf sín, uppeldisfræði, kennslu og nám nemenda sinna. Tilvikin leiddu í ljós að starfsþróun í skapandi stærðfræði getur haft áhrif á kennslu og nám. Auk þess komu í ljós þættir fyrir nám sem hafa verið settir fram sem líkan fyrir skapandi stærðfræðinám. Líkanið tengir saman verklega vinnu, leik og samræður í stærðfræði. Þessir þættir hjálpuðu kennurunum að búa nemendum skapandi nám. Með þátttöku í þessu ferli sáu kennararnir að viðhorf þeirra, kennsla og nám nemenda þróaðist. Þeir lýstu takmörkunum eins og tíma, stærð nemendahóps, kennslurými, samræmdum prófum og takmarkandi kennsluefni. Þessar niðurstöður og starfsþróunarprógrammið sem var þróað hafa gildi fyrir kennara, skólastjórnendur og þá sem skipuleggja kennaranám, starfsþróun, kennsluskrár og námsefni.Aðstoðarkennarastyrkur Háskóla Íslands 2020-2021
Rannsóknarsjóður Kennarasambands Íslands 2019-2021
Þróunarsjóður Skóla- og frístundasviðs 2018-2020
Sjóður Steingríms Arasonar Háskóla Íslands 201
Optimal protocol for spin-orbit torque switching of a perpendicular nanomagnet
Get PDF©2022 American Physical SocietyIt is demonstrated by means of the optimal control theory that the energy cost of the spin-orbit torque induced reversal of a nanomagnet with perpendicular anisotropy can be strongly reduced by proper shaping of both in-plane components of the current pulse. The time dependence of the optimal switching pulse that minimizes the energy cost associated with joule heating is derived analytically in terms of the required reversal time and material properties. The optimal reversal time providing a tradeoff between the switching speed and energy efficiency is obtained. A sweet-spot balance between the fieldlike and dampinglike components of the spin-orbit torque is discovered; it permits for a particularly efficient switching by a down-chirped rotating current pulse whose duration does not need to be adjusted precisely.Funded by the Russian Science Foundation (Grant No.19-72-10138), the Icelandic Research Fund (Grant No. 184949), the University of Iceland Research Fund (Grant No. 15673), and the Swedish Research Council (Grant No. 2020-05110).Peer Reviewe
Næringartengd lífmerki hjá barnshafandi konum og tengsl við meðgöngusykursýki
No full textBackground: Gestational diabetes mellitus (GDM) is one of the most common
complications diagnosed in pregnancy and is associated with several adverse
outcomes for mothers and their offspring. Several factors, both genetic and
environmental, are thought to affect a person’s risk of being diagnosed with
GDM. Increased age, overweight and obesity, sedentary lifestyle, a previous
history of GDM or giving birth to a child with macrosomia and family history of
diabetes are among known risk factors. Recent studies have indicated that diet
can also affect GDM risk, regardless of a women’s body mass index (BMI) and
other known risk factors.
Aim: This PhD thesis aimed to (a) examine dietary intake and nutritional status in
early pregnancy by means of a subjective diet screening questionnaire as well as
objective biomarkers (papers I-IV) and (b) explore associations with gestational
diabetes (papers I-III). Further aim was to compare results from the diet
screening questionnaire to biomarker results (papers I-IV).
Specifically, the aims were to: Determine the women´s intake of vitamin D,
measure serum 25-hydroxyvitamin (25OHD) and investigate associations to risk
of GDM diagnosis. Investigate associations between early pregnancy whole
grain intake, with the use of a whole grain biomarker and diet screening
questionnaire and explore associations to GDM diagnoses later in pregnancy.
Determine dietary intake as well as plasma fatty acid profiles in early pregnancy
and assess associations to later GDM diagnoses. Compare results of the diet
screening questionnaire to those derived from biomarkers of consumption.
Methods: Subjects were women attending ultrasound screening at the
Ultrasound Department at Landspitali - National University Hospital in their 11th to
14th week of pregnancy, from October 20178 to March 2018. During their visits,
the women answered a diet screening questionnaire as well as questions
regarding age, height, weight and background in addition to providing blood
and spot urine samples. The samples were analysed for concentrations of plasma
fatty acids, plasma alkylresorcinols (a biomarker for whole grain intake), and
serum 25OHD. Data on weight and gestational diabetes diagnoses were later
gathered from their medical records.
Results: GDM was diagnosed in 127 women (14.9%). Only 14.9% of the women
adhered to the recommendation of consuming two portions of whole grains daily
(Paper II). The women’s median intake of lean fish was approximately once
weekly, and their intake of fatty fish was approximately once monthly (Paper III).
Approximately one-third of the cohort had S-25OHD concentrations below
adequate levels (< 50 nmol/L) during the first trimester of pregnancy, thereof
5% had deficient concentrations (25OHD <30 nmol/L). However, no clear
vi
association was observed between S-25OHD and GDM (Paper I). Overall diet
quality in early pregnancy appeared to be lower among the women later
diagnosed with GDM (Paper III). The relative risk (RR) of being diagnosed with
GDM was 50% (95% CI: 0.27, 0.90) lower among individuals in the highest
quartile compared to those in the lowest quartile of plasma ARs (P-trend = 0.01)
after adjusting for age, pre-pregnancy BMI≥25 kg/m2
, parity, education,
smoking during pregnancy, and family history of diabetes. There was a
significant dose-response relationship between AR levels and GDM risk (Paper
II).
The total concentration of fatty acids (FAs) was significantly higher in women
diagnosed with GDM when compared to women without this diagnosis, as were
the concentrations of all types of FA—except for long-chain n-3 fatty acids
EPA+DHA. The mean adjusted difference for total FA between the women with
and without GDM was 133 μg/mL (95% CI 33 to 233) (Paper III).
There was a positive correlation between the women’s intake of all fish and total
omega-3 supplements and the concentrations of plasma omega-3 FA (r=0.34 P
<0.001). The women with a daily intake of cod liver oil or omega-3 oil
supplements displayed higher concentrations of EPA and DHA compared to
those who never used these supplements (median: 108 vs. 91 and 103 vs 90
μg/ml, respectively). A positive correlation was seen between reported intake of
vitamin D supplements and S-25OHD concentrations (r=0.31 P <0.001), and
higher reported frequency of whole grain intake was associated with a significant
increase in plasma AR concentrations (Papers I-IV).
Conclusion: These results indicate several opportunities to improve the diet and
vitamin D status of pregnant women in Iceland. The women who were not
diagnosed with GDM appear to have a slightly better adherence to dietary
recommendations overall. The role of vitamin D was not as clear in this context.
The associations of whole grain intake to GDM risk were established by
measuring plasma AR concentration, something that has not been done
previously in a pregnancy cohort. Our findings also indicate that the diet
screening questionnaire used in our study, is a tool that can be used to estimate
food consumption of selected food groups and intake of specific nutrients
during pregnancy.Rannsóknasjóður Háskóla Íslands og Vísindasjóður Landpítal
Mál á mannsævi : 70 ára þróun tilbrigða í framburði – einstaklingar og samfélag
Get PDFÁgrip: Í rannsókninni Mál á mannsævi er sjónum beint að tilbrigðum í íslenskum framburði, nánar tiltekið eftirtöldum fjórum pörum þar sem fyrrnefnda afbrigðið er sjaldgæfara á landsvísu og útbreiðsla þess að mestu tengd afmörkuðum landsvæðum: Harðmæli/linmæli, raddaður/óraddaður framburður, hv-/kv-framburður og skaftfellskur einhljóðaframburður/tvíhljóðaframburður. Þróunin er skoðuð frá ýmsum hliðum og markmiðið í senn að kanna hvaða breytingar hafa orðið á tíðni og dreifingu landshlutabundnu afbrigðanna á kjarnasvæðum sínum allt frá fyrri hluta 20. aldar og hvernig mál einstaklinga hefur þróast yfir æviskeiðið og varpa um leið almennu ljósi á málbreytingar.
Efniviðurinn samanstendur af þremur framburðarrannsóknum sem unnið var að á 70 ára tímabili. Tvær þær fyrri, rannsókn Björns Guðfinnssonar á 5. áratug 20. aldar og RÍN, Rannsókn á íslensku nútímamáli, frá 9. áratugnum, voru viðamiklar. Þær bjóða upp á ítarlega athugun á þróun tilbrigðaparanna á þessu skeiði, ekki síst vegna þess að grannskoðun á gögnum Björns leiddi í ljós að niðurstöðurnar má túlka á nákvæmari hátt en hingað til hefur verið unnt. Þróunin er skoðuð í ljósi málfræðilegra einkenna breytileikans, viðhorfa til afbrigða, sem könnuð voru sérstaklega í tengslum við rannsóknina og þróunar samfélagsins. Þannig er leitast við að skyggnast víða eftir skýringum.
Vinna hófst við síðustu rannsóknina árið 2010, RAUN, Málbreytingar í rauntíma í íslensku hljóðkerfi og setningagerð. Með henni er hægt að varpa ljósi á framhald fyrri þróunar, en að nokkru leyti verður sú mynd grófari en á fyrra skeiðinu. Á hinn bóginn býður RAUN upp á svokallaðan rauntímasamanburð því að einstaklingar sem tóku þátt í henni voru áður meðal þátttakenda í fyrri rannsóknum. Elsta fólkið skiptir tugum og í fjölbreyttu úrvali rauntímarannsókna er fáheyrt að svo stór hópur hafi tekið þátt í rannsóknum sem spanna jafnlangt tímabil. Efniviðurinn er nýttur til að skoða málþróun yfir æviskeiðið frá ýmsum sjónarhornum og leita svara við spurningum sem snúa að þessum tilteknu framburðarafbrigðum en hafa einnig almennara gildi. Spurt er hvort sum afbrigði frekar en önnur sæki á eða hörfi yfir æviskeiðið og hvort málfræðilegir þættir eða félagslegir geti átt hlut að máli. Um leið er leitast við að varpa nokkru ljósi á eðli slíkra ævibreytinga, hversu móttækilegt málkerfið sé fyrir breytingum á fullorðinsárum og hvaða kraftar séu þar að verki.
Af þessu má ráða að engin ein tilgáta eða sýn á málfræði og málbreytingar ræður ferðinni í rannsókninni, en það er ekki síst markmiðið að sýna fram á mikilvægi þess að einskorða sig ekki við þröngt sjónarhorn. Þá er sérstaklega horft til þess að félagsmálfræðingar og málkunnáttufræðingar hafa ekki að öllu leyti gengið í takt í rannsóknum sínum, viðhorfum og leit að skýringum á málbreytingum. Hér er róið á mið beggja þessara hópa, reynt að tvinna saman frekar en skilja að. Af þessum sökum er víða komið við í fræðilegri umfjöllum um málbreytingar, stiklað á stóru frekar en að kafa djúpt í einstök atriði. Þannig fæst mynd af víðfeðmi þessa rannsóknarsviðs þó að margra þátta sé ógetið.Abstract: The research project Mál á mannsævi (“Language in a lifetime”) focuses on the development of four variables or pairs of phonological variants in Icelandic, where one member of each pair is regional. There are two variants from North Iceland, so-called hard speech (“harðmæli” in Icelandic) which is characterized by aspirated stops after a long vowel in words like api, [a:pʰɪ] (‘monkey’), aka, [a:kʰa] (‘drive’), éta, [jɛ:tʰa] (‘eat’), which contrasts with soft speech (“linmæli”), lacking such aspiration. Then there is voiced pronunciation (“raddaður fram-burður”) with voiced sonorants before an aspirated stop in forms like hempa, [hɛmpʰa] (‘cassock’), vanta, [vantʰa] (‘need’), hjálpa, [çaulpʰa] (‘help’). In voiceless pronunciation (“óraddaður framburður”) the sonorants are unvoiced and the stops unaspirated. The variants soft speech and voiceless pronunciation are used by the majority in Iceland. From the south-eastern region there are also two variants. The hv-pronunciation (“hv-framburður”) in words like hvalur, [xa:lʏr̥] (‘whale’) has a voiceless velar fricative [x] in initial position, as opposed to the more common kv-pronunciation (“kv-framburður”) with [khv] in this position. Then there is the monophthongal pronunciation (“skaftfellskur einhljóða¬framburður”) which is a traditional name for long vowels in words like bogi, [pɔ:jɪ] (‘bow’), stigi, [stɪ:jɪ] (‘ladder’), as opposed to the more common diphthongal pronunciation (“tvíhljóða¬framburður”).
The development of these variables is examined from different points of view. The descriptive goal is to find out how the frequency and distribution of each regional variant has changed since the first half of the 20th century. The theoretical goal is twofold: To determine the effect of the different forces that can influence linguistic changes in a speech community and to shed a general light on language change in individuals during their lifespan.
The materials consist of three studies on pronunciation that were conducted over a 70-year period. The first two – a study by Björn Guðfinnsson in the 1940s, and Research on Phonological Variation in Modern Icelandic (acronym: RÍN, “Rannsókn á íslensku nútímamáli”) from the 1980s – were extensive. They offer detailed information on the development of the variables, especially because an examination of Guðfinnsson’s data has revealed that the results can be interpreted more accurately now than was previously possible. The development is studied by focusing on the different linguistic characteristics of the variants on the one hand and by examining sociolinguistic and social factors such as speakers’ attitudes towards the variants and the varying developments of the society in the relevant areas on the other. Thus, the study considers a broad range of internal and external factors in formulating an explanation.
Work began on the last study in 2010, Linguistic Change in Real Time in the Phonology and Syntax of Icelandic (acronym: RAUN, “Málbreytingar í rauntíma í íslensku hljóðkerfi og setningagerð”). With this addition to the earlier studies we can see the continuation of previous developments, but in some ways that image will be less clear than in the earlier period. However, RAUN offers so-called real-time analysis because individuals who participated in it were previously among the participants in Guðfinnsson’s study and/or RÍN. This material is used to view language change over the course of a lifetime from various perspectives and answer questions regarding these pronunciation variants but also has a more general value. The question is why some of the regional variants recede faster than others in the course of a lifetime. To what extent are linguistic factors and to what extent are social forces involved? Thus, the study seeks to shed some light on the nature of such lifetime changes, how responsive the language system is to changes in adulthood, and what forces are at work.
Because of this broad perspective, no single hypothesis or model of language change guides the journey in the study, and an important goal is to demonstrate the importance of not confining yourself to a narrow perspective. Underlying is the view that some kind of a bridge is needed between sociolinguists and generativists as they often use very different methods in their research and search for clarification of linguistic change. For this reason, the theoretical discussion about language change is wide-ranging, covering many topics, rather than delving deeply into a narrow area. We then gain a view of the breadth of this field of research, even though many factors go unmentioned.
The conclusions of the study are multifarious. One can, for example, detect an interesting concordance between urbanisation and economic development on the one hand and dialectical changes on the other, particularly in northern Iceland where these links could be studied in detail. The study also revealed an unexpected development of hard speech in later years, and there is an argument that the social status of this variant has changed or is changing. This local variant is fading but at the same time shows signs of strengthening during a lifetime in much the same way as “clear speech” (skýrmæli). Then it is argued that lifespan changes are more frequent earlier in life and that linguistic factors can influence the diffusion of language change. An important result is the fact that the coexistence of two variants of the same variable can have different effects on the linguistic environment depending on the nature of their differences. In some instances the differences are arguably rule-governed or regular, e.g. the difference between the voiced and voiceless pronunciation of the sonorants in words like hempa, vanta and hjálpa mentioned above. In other cases the differences are lexical, as the difference between the hv-and kv-pronunciation of words like hver ‘geyser’, where the kv-pronunciation makes hver homophonous with kver ‘booklet’, creating a confusing linguistic environment for those acquiring language in an area where both hv- and kv-pronunciaion exist. This difference in linguistic environment can lead to one change being more resilient than another for both new generations and adult speakers, or even for one of the groups and not the other.
The general conclusion of the thesis is therefore that the diffusion of language change is subject to both social and linguistic forces, which sometimes amplify one another
Identification of quality and environmental hotspots during pelagic fishmeal and fish oil production. Exploring process changes toward higher-value products and promoting positive environmental impacts by choice of energy sources
Get PDFÍ dag eru uppsjávartegundir, hliðarstraumar frá vinnslustærri fisktegunda og annar
meðafli uppistaðan í því hráefni sem unnið er í fiskmjöl og lýsi. Fiskmjöl og lýsi eru helst notuð sem fóður í fiskeldi, en þar sem verð á fiskmjöli hefur lækkað síðasta áratuginn og hlutur fiskmjöls hefur minnkað í fiskeldisfóðri, þarf að finna nýjar leiðir til að nýta hráefnið á hagkvæman hátt. Mikið hefur verið lagt í að bæta kælingu á hráefni uppsjávarveiðiskipa sem skila sér í betri gæðum þegar aflinn kemur í vinnsluna. Þessi þróun hefur þó ekki skilað sér í fiskmjöls- og lýsisvinnsluna, sem hefur lítið breyst síðan á sjöunda áratugnum.
Þessi rannsókn varpar ljósi á núverandi ástand á hráefninu og þeim gæðabreytingum sem eiga sér stað í hverju vinnsluþrepi í fiskmjöls- og lýsisframleiðslunni (Grein I-II), ásamt því að meta áhrif breytilegs hitastigs í sjóðara á gæði (Grein I), kannar hvernig framleiðsluferlið höndlar mismunandi hráefni (Grein II), rannsakar eiginleika hliðarstrauma m.t.t. próteingæða (Grein III), kannar umhverfisáhrif á framleiðslu fiskmjöls og lýsis úr loðnu með mismunandi orkugjöfum (Grein IV) og kannar hvort hægt sé að nota nærinnrauða litrófsgreiningu (NIR) til gæðamælinga og ferlastýringar í fiskmjöls- og lýsisframleiðslunni (Grein V). Greinarnar leggja grunninn að bættum fiskmjöls- og lýsisferlum og auka þekkingu á vinnsluferlunum sem mun nýtast við þróun þeirra næstu árin.
Þessi rannsókn sýndi jafnframt fram á að fituinnihald í fiskmjöli sem framleitt er í hefðbundnu fiskmjöls- og lýsisframleiðsluferli er breytilegt, en það mældist á bilinu frá 2% upp í 20%. Þröskuldur á fituinnihaldi fyrir hágæða fiskprótein miðast við fituinnhald innan við 0,5%, sem gefur til kynna að róttækar breytingar í vinnsluferlinu þurfa að eiga sér stað ef varan á að uppfylla kröfur til manneldis. Innihald himnufitu í fiskmjöli mældist hátt, sem bendir til þess að aðskilnaður fitunnar frá þurrefninu sé ekki nægur. Hins vegar benti magn frírra fitusýra til þess að niðurbrot af hráefninu var talsvert. Lækkun á hitastigi í sjóðara var rannsökuð til að skoða hvort fita skilaði sér betur frá þurrefninu, og fengust meiri gæði fiskmjöls við 85°C samanborið við 90° og 95°C (Grein I). Bent er á að bæta þurfi niðurbrot hráefnisins í fyrstu skrefum fiskmjöls og lýsisvinnslunnar, auk þess sem gufunin skilaði ekki eins lágu vatnsinnihaldi og búist var við (Grein I-II).
Fitu- og próteingæði voru rannsökuð í mismunandi hliðarstraumum og í hverju
vinnsluþrepi, og niðurstöður þessara rannsókna leggja grunn að vöruþróun á nýjum
afurðum og endurhönnun á vinnsluferlinum. Leysanleiki próteina í saltlausn (SSP) og styrkleiki lífrænna amín-sambanda minnkuðu í gegnum framleiðsluna, sem hafði áhrif á gæði fiskmjölsins, og benda til niðurbrots, líklega vegna mikils hita í vinnslunni (Grein II). Trímetýlamín (TMA) fylgdi vökvahlið vinnslunnar og jókst í gegnum framleiðsluna, en hagnstæð þróun sást í styrki dímetýlamíns (DMA). Þessi þróun gæti skýrst af flóknum niðurbrotsferlum trímetýlamínoxíð (TMAO) yfir í TMA og DMA, auk mikils hitaálags i vinnslunni.
Bættir vinnsluferlar, með lækkun hitastigs í sjóðara (Grein 1), sýndu fram á betri gæði fiskmjöls. Það gaf tilefni til að kanna hvort slík lækkun hitastigs skilaði mögulegum umhverfislegum ávinningi. Til þess að meta slíkan ávinning varlífsferilsgreiningu beitt, en aðerðin er stöðluð aðferðafræði. Lífsferilsgreining metur umhverfisáhrif umfram losun gróðurhúsalofttegunda og í þessari greiningu voru greind umhverfisáhrifin sem hljótast frá veiðum til og með vinnslu fiskmjölsins. Áhersla var lögð á að skoða áhrif mismunandi orkugjafa til vinnsluhlutans (fiskmjölsframleiðslunnar). Um orkufrekan iðnað er að ræða og því mikilvægt að kanna mismun á umhverfisáhrifum fiskmjölsframleiðslu knúinni með endurnýjanlegri orku annars vegar, sem og orku framleiddri með brennslu jarðefnaeldsneytis hins vegar. Það var gert til að sýna fram á mögulegan umhverfislegan ávinning af því ef fiskmjöl er framleitt með endurnýjanlegri orku. Til viðbótar, voru umhverfisáhrif af fiskmjölframleiðslu á Íslandi reiknuð miðað við mismunandi orkugjafa fyrir vinnsluárið 2018. Niðurstöður lífsferilgreiningarinnar sýndu að þrátt fyrir að lækkun hitastigs í sjóðara hafi einungis numið um 5°C, þá skilar slík lækkun minnkuðum umhverfisáhrifum sama hver orkugjafinn er. Það sýnir því að þróun vinnsluferla fiskmjöls, með áherslu á lækkun hitastigs vinnsluferla, gefur umtalsverðan ávinning við minnkun umhverfisáhrifa af fiskmjölsframleiðslu (Grein IV). Áhersla
framtíðarþróunar vinnsluferla í fiskmjölsframleiðslu ætti því að vera á enn frekari lækkun hitastigs í vinnsluferlum, án þess þó að minnka gæði vörunnar. Auk þess leiddi lífsferilsgreiningin í ljós að veiðarnar og vinnslan höfðu mest umhverfisáhrif (Grein IV). Áhrif mismunandi orkugjafa voru skilgreind út frá umhverfislegum áhrifum, sem kemur sér vel þegar skipta á út eða endurbæta vinnsluskref í vinnslunni. Auk þess voru talsverð umhverfisleg áhrif frá þeim hreinsiefnum sem notuð eru í vinnslunni, og er ráðlagt að skipta þeim út fyrir umhverfisvænni efni eða takmarka notkun þeirra. Þar sem vinnsluafköstin eru mikil, og endurhönnun eða gæðaeftirlit ferla á sér stað er mikill fjárhagslegur og umhverfislegur sparnaður fólginn í hraðari mælingum og eftirliti á gæðaþáttum í vinnslunni. Nútíma framleiðslukröfur gera ráð fyrir miklum áreiðanleika mælinga og einsleitari afurðum en áður. Litrófsgreiningar hafa verið nýttar í fjölbreyttum tilgangi við mati á framleiðsluferlum, þar á meðal nærinnrauð litrófsgreining (NIR) sem gæðaeftirlit á lokaafurðum í fiskmjöls- og lýsisframleiðslu. Í rannsókninni var NIR litrófsgreining notuð til að spá fyrir um breytingar á efnainnihald vinnslustrauma í gegnum vinnsluna alla. Spálíkön fyrir vatns- og fituinnihald, þurrefni, fosfólípíð, mettaðar fitusýrur, einómettaðar fitusýrur og fjölómettaðar fitusýrur, dókósahexaensýru (DHA) og eíkósapentaensýru (EPA) voru búin til með góðum árangri. Nýting á NIR litrófsgreiningu flýtir þannig greiningu mælinga umtalsvert og minnkar notkun á leysum og öðrum búnaði, og skilar sér í auðveldari stýringu vinnsluferilsins.Today, small pelagic species, side-streams from the production of larger fishes intended for human consumption, and other by-catch are currently processed into fishmeal and fish oil. Fishmeal and fish oil are presently mainly used as feed, primarily for aquaculture, but fishmeal prices have declined over the last decade. Great effort towards improving handling on board the fishing vessels has resulted in higher quality of the catch reaching the harbor. Meanwhile, the fishmeal and fish oil production processes have remained similar since the 1960s. Hence, this thesis aims to shed light on the current state of the raw material and the quality changes occurring during each operational step of the production (Paper I-II), to assess the effect of cooking temperature on the fishmeal quality (Paper I), investigates how the production process handles different raw materials (Paper II), investigates promising protein rich side-streams for the production of higher value products (Paper III), investigates the environmental impacts of producing 1 tonne of fishmeal and fish oil (Paper IV), and investigates if Near infrared spectroscopy (NIR) can be used as a monitoring tool during the fishmeal and fish oil production. The papers, I-V, also lay a foundation for redesigning purposes of the currently operated fishmeal and fish oil factories.
The study demonstrates that the traditional fishmeal and fish oil production processes currently returns high-lipid fishmeal from raw material ranging between 2% to 20% lipids. The lipid content should be less than 0.5% fat content to classify as
high-quality fishmeal, indicating that extracting lipids from the raw material is inefficient, and drastic changes need to happen if the products are intended for human consumption. Although a lower cooking temperature is proposed for higher quality fishmeal (Paper I), attention towards higher lipid separation during the initial production steps is suggested for a more effective breakdown of the raw materials. Further improvements suggest adjusting the evaporation step, as the concentrate was relatively high in water content compared to the other solid streams entering the drying steps (press cake, sludge, and concentrate) (Paper I-II).
Protein quality was investigated in promising side-streams, where salt soluble proteins content (SSP) decreased throughout the production, affecting the solubility of the fishmeal (Paper III). The same trend was observed in biogenic amines, indicating protein decomposition, possibly due to extensive heat treatment. The press-cake (solid stream) had the lowest amount of volatile nitrogen compounds during production from both the fatty and lean raw material. Trimethylamine (TMA) followed the liquid stream, increasing throughout the production, and reaching the highest values in the fishmeal, while the opposite trend was observed in Dimethylamine (DMA) concentrations. These trends could be the result of trimethylamine oxide degradation into TMA and DMA due to high thermal exposure during processing.
The effects of changing the cooking temperature on the fishmeal quality and processing efficiency were investigated, both on a quality basis and the effect on the environment. Lowering the cooking temperature by 5°C resulted in higher lipid quality fishmeal (Paper II), and overall lower environmental impacts (Paper IV). Furthermore, the environmental impacts were studied with environmental hot-spot analysis, assessed with the Life Cycle Assessment methodology in a cradle-to-gate study, based on the functional unit “the production of 1 tonne of capelin fishmeal including fish oil from cradle to factory gate, produced in Iceland in 2018. The assessment showed that the raw material acquisition was the highest environmental hotspot, contributing the most to almost all impact categories, followed by the production process. The assessed processing steps contributing the least to the assessed environmental impacts were packaging and back-up power, which effects were negligible, but cleaning agents (assessed with waste) were the highest contributors in many impact categories. The focus of the study included the effect of different energy sources for operating the fishmeal production, on the overall
environmental impacts, and changes in the environmental hotspots (Paper IV). Furthermore, Paper IV identified optimization potentials for lower energy consumption, e.g. using purse seiner compared to trawling, during the raw material acquisition. Identified steps with potential for lower environmental impacts of fishmeal and fish oil production lie within the drying and evaporation steps, and includes exchanging the current cleaning agents for more eco-friendly cleaning agents or limiting their use altogether. The environmental impacts of cleaning and waste were independent of the assessed energy sources for the processing.
In processes, such as fishmeal and fish oil production processes, with high throughput, and process redesigning, and quality monitoring are ongoing there is great financial and environmental gain to achieve by applying fast and robust monitoring techniques. Modern demands further require both higher precision in quality monitoring and higher product consistency than before. Spectroscopic analytical techniques have been used for a wide variety of quality assurance applications, including the use of near infrared spectroscopy to evaluate fishmeal and oil end-product quality. In the current study were NIR spectroscopy used to assess chemical composition of the streams throughout the whole process. Prediction models based on NIR data were successful in predicting water- and lipid content, fat free dry matter, phospholipids, along with the fatty acid classes (SFA, MUFA, PUFA), including docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) with acceptable precision. The application of NIR spectroscopy during the fishmeal and fish oil production provides faster analysis and minimizes the use of solvents, chemicals and instruments, which is reflected in easier process control and monitoring.
Increasing the quality of the raw material and reducing the environmental impacts requires excessive measurements, emphasizing the need for robust measuring methods to secure quicker and less costly analysis, e.g., the lipid quality and the separation from the water and FFDM. Assessing changes aimed to lower the environmental impact may not only reduce the energy cost but encourage sustainable practice and responsible production, as demonstrated in this thesis.AVS, Tækniþróunarsjóður, BIOZOOSTAIN, Rannsóknarsjóður HÍ, Matís og Síldarvinnsla
Initiating interactions in the toddler peer group: Embodied conversation starters
Get PDFTwo-year old children often express their understanding and intentions
through embodied interactions as they co-produce social relationships.
This article presents findings from an ethnomethodological study using
conversation analysis to explore turn-taking in toddlers’ interactions in a
preschool in Iceland. Here, we focus on how toddlers initiate interaction
through touch and gaze. These findings demonstrate that toddlers are adept
at reading social cues from their peers and are competent at turn-taking
and repair in embodied interactions resulting in significant exchanges in the
peer group. As such, this article contributes to a growing body of research
that demonstrates toddler’s competencies in organizing their own social
worlds through embodied strategies that co-construct peer relationships
in competent ways.Peer Reviewed; publishe
Concussion history among Icelandic female athletes : mental health, cognition and possible concussion biomarkers
Get PDFConcussion symptoms are complex. They are non-specific to a concussion, and there is
no gold standard for diagnosis and evaluation. For most, symptoms will resolve in days
or weeks following a concussion. However, symptoms can become more serious, lasting
for months or even years, considerably affecting quality of life. Long-lasting concussion
symptoms can include worse mental health and cognitive function, impaired sleep, and
ocular and vestibular problems. Sports are a significant risk factor for concussions.
Previous concussions, medical history and background, age and gender are also factors
influencing the prevalence and the sequela of concussion and progression of symptoms.
Despite being underrepresented in the concussion literature, many studies have found
that women are more at risk of sustaining a concussion and have more severe symptoms.
All of the participants in this study were Icelandic female athletes, retired and still active.
All had been playing at the highest level in their sport in Iceland. The aims of this Thesis
were to 1) examine the usefulness of self-report of concussion history and test if
different methods of obtaining self-report would affect the report given and the
relationship with an outcome variable; 2) examine concussion history and symptoms
among retired and still active female athletes and the relationship with mental health and
cognitive abilities; 3) validate self-reported concussion history and symptoms by
assessing phycological responses and physical markers in a virtual reality environment.
Self-reported history varied according to the method used to elicit concussion history.
This change indicates a lack of concussion knowledge and that detailed questioning
might be preferable when asking for a self-report of concussion history. This change and
how groups were formed depending on concussion count affected the relationship with
current symptoms. History of concussion was connected to poorer impulse control, more
current post-concussion symptoms and more problems with sleep, as well as more
anxiety and depression symptoms. Retired athletes with a concussion history tended to
have a worse outcome. When evaluating concussion symptoms and responses in a virtual
reality environment, biological signals showed discriminative powers when comparing
those with and without a concussion history. This supports their use as possibleiv
biomarkers for concussion. The Random forest algorithm predicted concussion history
with over 90% accuracy.
Overall, the findings support the use of self-report while assessing concussion history
and symptoms among female athletes with the appropriate framework. However, the
limitations of self-report and how they can affect results are also recognised. In addition,
results suggest that concussion history is connected to worse mental health and poorer
impulse control. The findings also highlight the use of a multimodal approach to
concussion assessment and support the use of several biological measures as possible
biomarkers for concussion. Results also underline the importance of including
technology from different fields in concussion assessmentEinkenni sem hafa verið kennd við heilahristing eru flókin, þau eru ekki sértæk fyrir
heilahristing og það er engin ein algild leið til þess að greina og meta heilahristing.
Flestir jafna sig á einkennum á nokkrum dögum eða vikum. Hins vegar, geta einkenni
orðið mjög slæm, varað í nokkra mánuði eða ár og haft mikil áhrif á lífsgæði.
Langtímaafleiðingar eftir heilahristing geta verið verri líðan og hugræn geta, verri svefn
og vandi með augnhreyfingar og jafnvægi. Íþróttir eru einn þeirra áhættuþátta sem hefur
mikið vægi þegar kemur að heilahristing, þó ekki fylgi öllum íþróttum jafn mikil áhætta.
Fyrri heilahristingssaga, heilsa og bakgrunnur hafa jafnframt áhrif, en einnig aldur og
kyn. Allt eru þetta þættir sem hafa áhrif á algengi og afleiðingar heilahristings. Þrátt fyrir
að konur eru ekki eins mikið rannsakaðar og karlar gefa margar rannsóknir til kynna að
konur séu í meiri hættu á því að fá heilahristing og glími við alvarlegri einkenni.
Allir þátttakendur í þessari rannsókn voru íslenskar íþróttakonur sem annað hvort voru
enn að æfa og keppa í efstu deildum í sinni íþrótt, eða voru hættar. Markmið þessa
verkefnis voru að 1) skoða gagnsemi þess að fá þátttakendur sjálfa til að greina frá
heilahristingssögu sinni ásamt því að meta hvort mismunandi aðferðir við að fá fram
heilahristingssögu hafi áhrif á það sem er uppgefið og tengsl við fylgibreytur; 2) skoða
heilahristingssögu og einkenni meðal íþróttakvenna, sem eru hættar og þeirra sem eru
enn virkar, og meta samband við líðan og hugræna getu; 3) staðfesta mat á eigin
heilahristingssögu og einkennum með því að skoða svörun og líffræðileg merki sem
safnað var í sýndarveruleika.
Mat á heilahristingssögu breyttist á milli aðstæðna og var háð því hvaða upplýsingar
voru gefnar og hvernig þáttakandi var beðinn um að rifja upp. Þessi breyting bendir til
þekkingarleysis á heilahristing og að nákvæmari spurningar um heilahristingssögu séu
mikilvægur hluti af gagnasöfnun þegar nota á sjálfsmat. Þessi breyting og það hvernig
hópar voru myndaðir út frá fjölda heilahristinga hafði áhrif þegar tengslin við fylgibreytu
voru metin. Tengsl voru á milli heilahristingssögu og stýrifærni, núverandi
heilahristingseinkenna, meiri svefnvanda, og kvíða-og þunglyndiseinkenna. Þeim
íþróttakonum sem áttu sögu um heilahristing og voru hættar keppni gekk í mörgum
vi
tilvikum verr en öðrum hópum. Merki frá nemum sem mældu líffræðilega svörun við
áreiti í sýndarveruleika gáfu ennfremur til kynna að hægt var að greina á milli þeirra sem
greindu frá sögu um heilahristing og þeirra sem ekki greindu frá heilahristingssögu.
Niðurstöður stiðja því að hægt sé nota þessi merki sem viðmið við mat á
heilahristingseinkennum. Með notkun Random forest reikniritsins var hægt að spá fyrir
um heilahristingssögu með yfir 90% nákvæmni.
Þegar á heildina er litið gefa niðurstöður þessa verkefnis til kynna að hægt sé að styðjast
við sjálfsmat á einkennum og heilahristingssögu. Þó er mikilvægt að vera meðvitaður um
þær takmarkanir sem kunna að fylgja þessari aðferð og áhrifum á niðurstöður. Að auki
benda niðurstöður til þess að tengsl séu á milli heilahristingssögu og verri andlegrar
heilsu og að hluta til stýrifærni. Niðurstöður undirstrika einnig mikilvægi þessa að notast
við fleiri en eina mælingu við mat á einkennum og mikilvægi þess að nýta aðferðir sem
koma úr ólíkum áttum við mat á heilahristing. Með því opnast fleiri möguleikar á
mögulegum greiningarviðmiðum fyrir heilahristin
Into the Enclosure: Collective Memory and Queer History in the Icelandic Documentary “People like That”
Get PDFThis article criticizes an acclaimed Icelandic documentary film series from 2019, People Like That („Svona fólk“), which has become the quasi-canonical history of the country‘s gay and lesbian rights struggle. The series tells the story of the forward march of normalizing progress and change from below, starting in the late 1970s and breaking through with the achievement of registered partnership in 1996. This article views the series as an attempt to create a collective memory corresponding to Iceland‘s new self-image as a queer utopia and Nordic equality paradise. While avoiding historicist criticism, the article presents new stories and memories from the documentary series‘ own archive, which has been partly released online, and sources unexplored by the series, such as queer journals and reports by the state and the National Church on homosexuality from the 1990s. From these stories, different narratives of Iceland‘s recent past emerge, in which homonormativity is imposed by the Icelandic state and National Church in the 1990s and conceded by Iceland‘s National Queer Organization, resulting in a registered partnership legislation that some homosexual Icelanders saw not as a victory but as a loss of power. The contrast between these stories and those of People Like That foregrounds the politics of remembrance and forgetting and exposes the seldom discussed conditions for Icelandic homosexuals‘ inclusion into the nation in the 1990s.Icelandic Centre for ResearchPeer Reviewe
Cross-cutting palaeo-ice streams in NE-Iceland reveal shifting Iceland Ice Sheet dynamics
Get PDFIce streams are thought to have regulated the past Iceland Ice Sheet (IIS) during and following the Last Glacial Maximum (LGM) by discharging ice and sediment from the interior of the ice sheet towards the shelf edge. Previous assessments of ice streams within the IIS have produced contradictory reconstructions of ice sheet dynamics and location of ice divides. Here, we reconstruct palaeo-ice streams in NE-Iceland based on detailed mapping of streamlined subglacial bedforms (SSBs) and other glacial lineations. The morphometrics, distribution and orientation of the SSBs indicate the flow-sets of several cross-cutting palaeo-ice streams and the location and migration of ice divides, while high density and packing of SSBs possibly suggest the axial zones of the ice streams. North-trending flow-sets suggest that during maximum glaciation and ice-sheet thickness, ice flow within the study area was largely unaffected by underlying topography allowing ice to flow northwards across valleys and fjords. This ice flow direction correlates with the orientation of previously identified troughs on the north-eastern shelf and indicates that an E-W orientated ice divide was located to the south of the study area. During deglaciation and ice sheet thinning, a N-S orientated ice divide was located to the west of the study area, and palaeo-ice streams became confined to valleys and fjords, so that associated flow-sets crosscut the older ones. The absolute ages of these flow-sets are uncertain, but the simplest interpretation is that the older ones pertain to the LGM and the younger ones to the following deglaciation. This study sheds light on the dynamics and evolution of palaeo-ice streams within the IIS and highlights the importance of further efforts to understand the subglacial processes responsible for the formation of the streamlined subglacial bedforms as well as to constrain the evolution of shelf glaciation and chronology of ice stream retreat.University of Iceland Research Fund, the Icelandic Road and Coastal Administration, and the Energy Research Fund of Landsvirkjun.Pre-print (óritrýnt handrit